To investigate the occurrence of sick leave (SL) and the impact of clinical and socioeconomic factors on SL in early axial spondyloarthritis (axSpA).Patients with a clinical diagnosis of axSpA from the DEvenir des Spondyloarthrites Indifférenciées Récentes (DESIR) cohort with work-related data and up to 5-year follow-up were studied. Incidence, time to first SL and potential role of baseline and time-varying clinical and socioeconomic factors  were analysed. Univariable analyses, followed by collinearity and interaction tests, guided subsequent multivariable time-varying Cox survival model building.In total, 704 axSpA patients were included (mean (SD) age 33.8 (8.6); 46% men). At baseline, 80% of patients were employed; of these, 5.7% reported being on SL. The incidence of SL among those at risk during the study period  was 0.05 (95% CI 0.03 to 0.06) per 1000 days of follow-up. Mean (SD) time to first SL was 806 (595) days (range: 175–2021 days). In multivariable models, male gender (HR 0.41 (95% CI 0.20 to 0.86)) and higher education (HR 0.48 (95% CI 0.24 to 0.95)) were associated with lower hazard of SL, while higher disease activity (HR 1.49 (95% CI 1.04 to 2.13)), older age, smoking and use of tumour necrosis factor inhibitors were associated with higher hazard of SL.In this early axSpA cohort of young, working-age individuals, male gender and higher education were independently associated with a lower hazard of SL, whereas older age and higher disease activity were associated with higher hazard of SL. The findings suggest a role of socioeconomic factors in adverse work outcomes, alongside active disease. Data on sick leave as an adverse work outcome in axial spondyloarthritis (axSpA) are sparse and generally limited to established radiographic axSpA.With a focus on socioeconomic factors, this study identifies personal contextual factors such as lower education, older age and female gender to be independently associated with a higher hazard of sick leave.This study provides evidence for the association between high disease activity and sick leave in early axSpA.In early axSpA, older age, female gender and lower educational attainment are associated with higher sick leave and should therefore be considered when tailoring care and supporting individuals in their work role.From the early stages of the disease, it is important to consider personal contextual factors and control disease activity in an attempt to avoid sick leave.Axial spondyloarthritis (axSpA) is a disease of young individuals, typically of working age.5–9The findings of studies to date that have sought to examine specifically SL, vary widely in the literature and across countries.18Studies in longstanding r-axSpA suggest that lower social class as reflected by lower educational status, manual/physically demanding jobs, associate with unfavourable work outcomes.Acknowledging the general lack of data in early disease and using one of the most well-established early axSpA cohorts in Europe, the DEvenir des Spondyloarthrites Indifférenciées Récentes (DESIR) cohort, we wished to explore the occurrence of SL and the impact of clinical and socioeconomic factors on SL.Data from the French prospective, nationwide, multicentre (n=25 centres) DESIR cohort  were used.Free-text information provided in the case-reporting form (CRF) was also used where available to supplement the information and help group patients into working and non-working categories. Written informed consent was obtained from participating patients before inclusion into the study.Information on SL was based on self-report and obtained every 6 months during the first 2 years of follow-up and yearly thereafter via three main routes: (a) questions where the patients were asked to report that they were on SL; (b) questions asking for a date of SL; (c) text information provided by patients including reasons for not working.A patient was categorised as being in ‘first sick leave’ from the time point for which they first reported SL, until the last time point on which they reported SL and the date that was given was the same as (or within one month of) the date they reported for their first SL. A patient was categorised as being in ‘recurrent sick leave’ if they reported SL and a date was given that was more than one month after the date they reported for their first SL.Patient responses varied and discrepancies were noted in the way patients completed the relevant questions on SL and date for this. For example, despite a record of SL, a date was not always provided and vice versa. When a patient reported SL as the reason for not working but did not provide a date in the relevant question on the CRF for SL, the date of SL was imputed as the mid-date between the current date of consultation (at which they reported being on SL) and their previous date of consultation. Patients retired, those with work disability and those with a date of SL prior to their baseline date of consultation, were considered as not ‘at-risk’ for the SL outcome. They may have though contributed to the analyses of SL over time during the period they were ‘at risk’, for example, when work disability occurred during the follow-up. Inaccuracies in the dates of SL reported and also its duration  prompted a restriction in the analysis to factors associated with the first episode of SL .Socioeconomic variables were among the main independent variables of interest, along with clinical variables. The majority of variables were assessed at the same time points as those of SL; some only at baseline (see below). Variables were used in their time-varying form  where appropriate to ensure optimal use of the data available.Socioeconomic variables included age, gender, educational status (low (primary or secondary education) vs high (university education)), ethnicity (Caucasian vs other), job type  vs white-collar ), marital status (married/in couple vs not) and parental status (number of children), included in their time-varying form.Clinical outcomes of interest included measures of disease activity, function and spinal mobility, all included in their time-varying form. For disease activity, the Ankylosing Spondylitis Disease Activity Score (ASDAS) with C reactive protein (CRP) and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) were used. Laboratory measures of inflammation included CRP measured in mg/L in its continuous form, as well as in a binary form of the variable to indicate raised (>6 mg/L) versus non-raised CRP at every visit. Measures of physical function included the Bath Ankylosing Spondylitis Functional Index (BASFI) and for mobility, the Bath Ankylosing Spondylitis Metrology Index (BASMI).Other variables included in the analysis in their time-varying form, included smoking (current vs non-current smoker since last visit), history of extra-musculoskeletal manifestations, namely uveitis, psoriasis and inflammatory bowel disease (IBD). Disease characteristics recorded at entry into the study and used in their baseline form, included: symptom duration studied as a continuous variable; presence of Human Leukocyte Antigen B27 (HLA-B27) and hip involvement. Imaging outcomes studied included sacroiliac joints (SIJ) radiographs using the modified New York grading 22Comorbidity burden was reflected in a comorbidity ‘count’ variable that was computed to include the following comorbidities: chronic pulmonary disease, ischaemic heart disease, pericarditis, heart failure, cardiac valve disease including aortic insufficiency, heart rhythm disorders, hypertension, cerebrovascular accidents, diabetes, gastric ulcers/perforation/haemorrhage, lymphoproliferative disease, organ neoplastic disease, depression/anxiety .Treatment variables were analysed in their time-varying form: non-steroidal anti-inflammatory drugs (NSAIDs) based on computation of the Assessment of SpondyloArthritis international Society (ASAS) NSAID Score (0–400),Descriptive statistics for baseline characteristics of patients in the study population and those ‘at-risk for sick leave’ at any point during follow-up were applied. The incidence rate of SL from those ‘at-risk’ of the outcome (SL) among the total study population was calculated based on the total at-risk observation time, in days. In other words, this was the sum of the days that each patient was at risk  or reaching the 5-year follow-up).2 or Fisher’s exact test for categorical variables.Patients who at any point during the at-risk period developed SL (‘Ever sick leave’) were compared with those who did not report SL during the at-risk observation period (‘Never sick leave’). These groups excluded patients reporting SL at baseline and those retired. Comparisons between the ‘Ever sick leave’ versus the ‘Never sick leave’ categories were undertaken using the Wilcoxon test for continuous variables (skewed distribution) and either the χTime-varying cox survival analysis was used to study time to first SL for all patients who were at risk of SL at any time point during the 5 years of DESIR. A patient was considered a ‘failure’ at the date of consultation at which they first reported SL. The multivariable model analyses were guided by relevant interaction analyses, namely between disease activity (ASDAS) or function (BASFI) and each of the following: age, gender and education. Where statistically relevant interactions (p<0.150) were identified, model stratification was performed to assess the clinical relevance. A multistep technique was followed to identify the most parsimonious, multivariable models for the impact of clinical and socioeconomic factors on SL. First, univariable analysis was undertaken with SL as the dependent outcome. Variables with a p<0.20 were subsequently tested in stepwise forward Cox regression models. Socioeconomic and clinical variables were entered first as main variables of interest. Variables were retained in the models if significant at the p<0.05 level or if identified as confounders of the socioeconomic variables (resulting in a change of the HR by >15%). Collinearity checks were also undertaken between individual variables, followed by testing of the final models for multicollinearity and violation of proportional hazards. Separate models have been constructed with the main clinical variables  where necessary, to allow for the individual effects of these variables to be explored.Sensitivity analyses were performed in the subgroup of patients fulfilling the ASAS classification criteria,A total of 704 (99%) patients in DESIR had provided information on work-related data and could be studied. At baseline, the mean (SD) age of the eligible study population was 33.8 (8.6), with 46% being men and 90% of Caucasian ethnicity. Higher (university) education was attained by 59%. At baseline, mean (SD) ASDAS was 2.7 (0.9), BASFI 3.0 (2.3) and BASMI 2.4 (1.0). The study population was categorised into patients who were in employment (including those on SL), a total of 561 patients (80%), or unemployed . Baseline characteristics for the study population are shown in 10.1136/rmdopen-2021-001685.supp1Supplementary dataOf 561 working at baseline, 5.7% (n=32) reported being on SL already at study baseline. Of the total study population, 88% (n=620) were at risk of a future episode of SL over the study period and were included in the time-to-event analyses of SL. Patients reported being in and out of SL at various time points throughout the study. The distribution of first and recurrent SL episodes over the 5 years of follow-up is shown in In total, 43 (7%) of patients reported SL for the first time during the 5 years of follow-up , with the mean (SD) time to SL being 806 (595) days, minimum 175 days, maximum 2021 days (5.5 years). A first SL was reported by 25% of patients at 364 days of follow-up: by 50% and 75% at 545 and 1172 days, respectively. The SL incidence rate across the study follow-up and among those at risk of SL was 0.05 (95% CI 0.03 to 0.06) per 1000 days calculated in a total person-days of observation of 913 559. The latter represents the total time (in days) of all patients (n=620) at risk for SL (from entering the at-risk period to the end of follow-up or to the first ‘failure’).Significant differences were noted in the baseline characteristics of patients who reported SL at any point during the study (‘Ever sick leave’) compared with those who never did (‘Never sick leave’). This was notable for socioeconomic factors where for example older age, more females, lower education, being in married/couple relationship were seen in those who were ‘Ever’ on SL. Similarly, higher disease activity and more use of NSAIDs were seen in those in the ‘Ever sick leave’ group . AlthougNo clinically relevant interactions were identified that necessitated model stratification. Several clinical and socioeconomic variables were univariably associated with SL; for instance, higher education was associated with a lower hazard of SL with a HR of 0.33 (95% CI 0.17 to 0.61) .In multivariable models, time-varying higher disease activity was associated with more SL. Specifically, every unit increase in ASDAS was associated with a 49% increase in the hazard of SL. Similarly, older age, smoking and use of TNFi, were associated with a higher hazard of SL. In separate models and unlike disease activity, functional ability (BASFI) and spinal mobility (BASMI) were not significantly independently predictive of SL. Across all models, male gender and higher education were associated with a lower hazard of SL: in the ASDAS model, with a 59%  and 52%  decrease in the hazard of SL, respectively. Smoking strongly associated with a higher hazard of SL (HR >2.5) across all models. The use of TNFi was significantly associated with a higher hazard of SL and in the case of the BASFI model, steroid use was also significantly associated with a higher hazard of SL. The effect of education in the main model is also graphically shown in Baseline characteristics of the ASAS criteria fulfilling subgroup of DESIR  are shown in This study, based on data from an early axSpA cohort of young, working-age individuals, reveals two main observations. First, that the incidence of SL in early axSpA is low and second, that both clinical and socioeconomic factors independently associate with SL. Specifically, across the study group, higher (university) education and male gender independently associated with a lower hazard of SL and older age and higher disease activity with higher hazard of SL. The findings suggest a role of socioeconomic factors, alongside active disease, in an important, yet generally poorly studied adverse work outcome: SL. The higher hazard of SL in those with higher disease activity even in the early stages of disease, suggests room for ‘intervention’ to prevent this adverse work outcome, especially in an era of biologics and other advanced therapies.The association between education and SL is one that has been reported before, although in established disease and with education as a modifier of the association between disease activity or function and SL as opposed to an independent predictor.Despite a consistency in our findings of worse disease activity relating to more SL with previous studiesOur study has several clinical implications, both from an individual as well as a societal perspective. The undertaking of SL is to a large extent a decision of the individual and could relate to underlying personal contextual factors. This may explain why educational status has been found in our study and in previous studies to be significantly associated with SL. The potential impact of this outcome on the health and social security system could also be substantial; in this respect, relevant education of both employees and employers but also rheumatologists, could play a role in guiding effective interventions to improve work ability and reduce SL. In addition, with previous reports suggesting a first episode of SL to predict future episodes of SL,On the other hand, the contextual dependence of SL, could also represent a drawback. For example, individuals are likely to take more SL, if there is the financial safety net that allows them to do so. Social security systems and available support to employees varies across countries, thus limiting the generalisability of results. For example, in France individuals are entitled to paid SL, including extended SL, for serious or long illnesses, provided there is adequate supportive information. Paid SL can be up to 12 months, usually capped at 360 days within 3 years; however, paid SL can be granted for up to 3 years.So, an important limitation of our study findings is the potential lack of generalisability of results. However, it is worth noting that, a study on SL across three nations showed no effect of country of residence on this outcome.Longitudinal data are necessary to look at potential factors that associate with SL, especially when they provide the possibility to study time-dependent variation of potential explanatory variables. In this regard, the DESIR cohort becomes uniquely relevant, especially in the study of socioeconomic factors which may have long-term influence on adverse work outcomes such as SL. We purposefully placed emphasis on the study of socioeconomic alongside clinical data, taking advantage of the recording of the former data in DESIR, which has led to the most parsimonious models being ones that indicate both socioeconomic and clinical factors to be contributory to SL. Furthermore, and as highlighted above, considering that most studies to date have focused on determinants of SL in established axSpA (r-axSpA),In conclusion, this study has shown that the incidence of SL in this early axSpA cohort of young, working-age individuals is low. It also provides a deeper understanding of factors beyond clinical disease that associate with adverse work outcomes. The study suggests that, beyond the disease itself and its activity, socioeconomic factors associated with a potentially reversible adverse work outcome: SL. Thus, an appreciation of personal contextual factors and their potential independent association with SL, could allow the tailoring of care around individual needs and support people in their work role.


Background: Heroin addiction and withdrawal have been associated with an increased risk for infectious diseases and psychological complications. However, the changes of metabolites in heroin addicts during withdrawal remain largely unknown.Methods: A total of 50 participants including 20 heroin addicts with acute abstinence stage, 15 with protracted abstinence stage and 15 healthy controls, were recruited. We performed metabolic profiling of plasma samples based on ultraperformance liquid chromatography coupled to tandem mass spectrometry to explore the potential biomarkers and mechanisms of heroin withdrawal.Results: Among the metabolites analyzed, omega-6 polyunsaturated fatty acids , omega-3 polyunsaturated fatty acids , aromatic amino acids , and intermediates of the tricarboxylic acid cycle  were significantly reduced during acute heroin withdrawal. Although majority of the metabolite changes could recover after months of withdrawal, the levels of alpha-aminobutyric acid, alloisoleucine, ketoleucine, and oxalic acid do not recover.Conclusions: In conclusion, the plasma metabolites undergo tremendous changes during heroin withdrawal. Through metabolomic analysis, we have identified links between a framework of metabolic perturbations and withdrawal stages in heroin addicts. Heroin, an illegal, highly addictive drug, is extremely harmful to human physical and mental health , 2. HeroNeuroimaging studies have shown that dysfunction of the nucleus accumbens functional network is present in long-term withdrawal (> 3 years) heroin-dependent individuals . CompareIncreasing data indicate that the metabolic changes of fatty acids (FAs) are involved in a variety of neurodegenerative diseases and neuropsychiatric diseases –17. FAs The advances in metabolomics provide powerful tools for profiling global biochemical changes in disease and treatment, which simultaneously identify and quantify hundreds to thousands of metabolites, providing an excellent opportunity to profile the metabolic changes in a high-throughput manner. Although brain tissues or cerebrospinal fluid are ideal biological samples for research on neuropsychiatric disorders, they cannot be practically obtained because of ethical and safety concerns. In comparison, blood samples can be acquired at minimal risk and cost. Furthermore, because the concentration of peripheral blood metabolites is closely related to pharmacological or toxicological effects, and because it can reflect the current state of the organism, metabolites in the peripheral blood are increasingly used to discover disease biomarkers , 25. In A total of 35 male heroin addicts including 20 with acute abstinence stage (ABS) and 15 with protracted abstinence stage (PABS), as well as 15 healthy controls (HCs), were recruited and analyzed in this work. The demographic characteristics of the participants are presented in Using UPLC-MS/MS, 129 endogenous plasma metabolites  were identified, including 43 AAs, 51 FAs, eight short-chain FAs (SCFAs), and 27 OAs . The oveMultivariate statistical analysis was performed to compare the differences in plasma metabolic profiling among the three groups. As shown in the score plot of PLS-DA , a clearTo obtain additional data about the differential metabolites of each group, we adopted univariate and multi-dimensional statistical methods and screened out the differential metabolites that met the double standard. These metabolites were the most reliable differential markers and may become potential biomarkers. The final list of screened differential metabolites, which met the set threshold (VIP ≥ 1 and p < 0.05), are displayed in We developed a pathway analysis bubble plot based on different metabolite results obtained from comparison of two group each, combined with pathway enrichment analysis and pathway topology analysis to facilitate biological interpretation and thereby reveal the most relevant pathways involved in heroin withdrawal , 3D, 3F.In this study, we implemented UPLC-MS/MS–based metabolomics approaches to investigate the alterations of metabolites in the peripheral blood of heroin addicts undergoing withdrawal in different stages. This study aimed to identify potential biomarkers and elucidate the possible mechanism involving heroin withdrawal from a metabolic perspective.The clinical characteristics of depressive and anxiety symptoms are closely related to blood levels of PUFAs , 29. In Emerging studies have shown that n-3 PUFAs support health and reduce the risk of chronic diseases , 36. LowAromatic AAs include phenylalanine (Phe), tyrosine (Tyr), and tryptophan (Trp). Phe can be transformed into Tyr through phenylalanine hydroxylase, and Tyr could be metabolized further into neurotransmitters, such as dopamine, norepinephrine, epinephrine, and melanin, through the action of tyrosine hydroxylase. Trp could be metabolized through the kynurenine and serotonin pathways to produce biologically active compounds, such as serotonin, melatonin, and niacin. Heroin damages the reward system by affecting the activities of dopaminergic, gamma-aminobutyric acid (GABA), serotonergic, and cholinergic neurotransmitters in the central nervous system , 42. As The TCA cycle is carried out in the mitochondrial matrix of the human body. It is the final metabolic pathway of the three main nutrients  and is the hub of energy metabolism. Our results suggest that, during acute heroin withdrawal, oxoglutaric acid and isocitric acid are significantly reduced. The two are important intermediate products of the TCA cycle. The synthesis of oxoglutaric acid from isocitric acid is an important rate-limiting step in the TCA cycle. The reduction of these metabolites indicates that the TCA cycle is largely affected, mitochondrial function is impaired, energy metabolism is weakened, and productivity is reduced during heroin withdrawal. This finding suggests that the TCA cycle is downregulated during acute heroin withdrawal. However, the results of animal experiments are contrary to this. Results from Zheng et al.  show thaIn addition, we found that pyruvic acid  in PABS showed a significant downward trend compared with HCs and ABS. The human brain is a highly metabolized organ, and its energy requirements are almost entirely derived from the metabolism of glucose and pyruvic acid . In our Heroin has a lasting effect on the metabolism of the human body. Even after several months of heroin withdrawal, four metabolites  remain unrecovered. Alpha-aminobutyric acid is closely related to the metabolism of glutathione in the body . GlutathCompared with other diseases, human metabolomics data in the field of drug addiction remain limited. Our data support the findings from previous animal studies and we found that metabolism of heroin addicts in the acute withdrawal period is significantly different from that in the late withdrawal period. In particular, the metabolism of essential FAs, neurotransmitter precursors and energy production pathways were obviously abnormal, and these insights might provide a strategy for intervention in heroin addicts during withdrawal.In this case-control study, a total of 35 men with heroin withdrawal were recruited from a joint program of drug detoxification and rehabilitation in the First Affiliated Hospital of Kunming Medical University and the Kunming Drug Rehabilitation Center from January 2018 to October 2019, including 20 patients with acute abstinence stage (ABS) and 15 patients with protracted abstinence stage (PABS). All patients had a clear history of heroin use that was confirmed by urine screening tests. Fifteen age-, sex-, and body mass index–matched non-heroin-use volunteers were enrolled as healthy controls (HCs). All protocols and recruitment procedures described in this study were approved by the Research Ethics Committee of the First Affiliated Hospital of Kunming Medical University (2018-L-42), and the study was conducted according to the tenets of the Declaration of Helsinki. All participants provided written informed consent before enrollment.Blood samples were collected and stored in the First Affiliated Hospital of Kunming Medical University Biobank using standard procedures. Peripheral venous blood was collected from fasted participants with heroin withdrawal and from HCs between 08:00 and 10:00 AM using Vacutainer blood collection tubes with EDTA as an anticoagulant. The anticoagulant-treated blood samples were gently mixed by inverting the tube several times. Blood samples were then centrifuged at 3,000 g for 10 min at 4° C. The upper layer, containing plasma, was transferred to a 2-mL Eppendorf tube (500 μL per tube) and immediately stored at −80° C until use. The protocols for preparation and derivatization of plasma samples were based on a previously published method, with minor modifications. In brief, 50 μL of plasma was weighed and transferred to a new 1.5-mL tube, and 20 μL of methanol/chloroform/water (3:1:1) was added. The sample was homogenized with zirconium oxide beads for 3 min and then was centrifuged at 18,000 g for 20 min. The supernatant was transferred to a 96-well plate, and 20 μL of freshly prepared derivative reagents was added to each well. The plate was sealed, and the derivatization was carried out at 30° C for 60 min. After derivatization, 350 μL of supernatant was transferred to a new 96-well plate with 15 μL internal standards in each well. Serial dilutions of derivatized stock standards were added to the left well. Finally, the plate was sealed for UPLC-MS/MS analysis.Demographic, continuous variables were expressed as the mean ± standard deviation. We used the Wilcoxon test to analyze continuous variables and either the Fisher test or chi squared test to analyze categorical variables. A p value < 0.05 was considered statistically significant. The raw data files generated by UPLC-MS/MS were processed using the iMAP platform . Partial least squares-discriminant analysis (PLS-DA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were also performed. PCA is an unsupervised data analysis. It can be used to evaluate whether possible abnormal samples and outliers were present through the aggregation/separation of observation points. Each point represents a sample. If points exceed the 95% confidence interval, they will appear outside the ellipse and may be an outlier sample. PC1 is the first principal component of the model, and PC2 is the second principal component of the model. OPLS-DA was used to distinguish the differences in metabolic profiles between the two groups. In the OPLS-DA score plot, the abscissa P1 represents the first predicted principal component of the model, the ordinate O1 represents the first orthogonal component of the model, and the percentage in parentheses represents the interpretation rate of the principal component. The variable importance in projection (VIP) was obtained according to the OPLS-DA model. Metabolites with VIPs of ≥ 1 and p < 0.05 were regarded as statistically significant.  The heat plot of metabolites was formed with the iMAP platform, after unit variance scaling for each metabolite. To explore the related metabolic pathway disruptions in more detail, iMAP platform, Human Metabolome Database, and the Kyoto Encyclopedia of Genes and Genomes were used.Supplementary Figure 1Supplementary Table 1Supplementary Table 2


Chlorella vulgaris (CV) and Spirulinaplatensis (SP)) powders were investigated in respect to their thermal stability after γ-irradiation. The material durability under accelerated degradation was qualified by chemiluminescence and gelation, which prove the contribution of inorganic filler and microalgae extracts on the increase of hybrid thermal stability, as well as the interaction between added components (POSS and CV or SP). The activation energies and the durabilities under accelerated degradation were calculated, indicating their suitable usage as appropriate materials in various applications. The reported results indicate the improvement effect of both microalgal powders on the oxidation strength, but the contribution of Spirulinaplatensis grabs attention on its efficient effects upon the prevention of degradation under accelerated aging conditions. The thermal performances of the tested EPDM based hybrids are remarkably ameliorated, if the certain formulation includes Ov-POSS (5 phr) and Spirulinaplatensis (2 phr), certifying its suitability for the pertinent applications.The EPDM (ethylene-propylene-diene monomer) hybrids with improved thermal and radiation strengths containing 1 and 5 phr of polyhedral oligomeric silsesquioxane  and/or 2 phr of microalgae ( As it may be noticed from the literature, the investigations on the extension of material life generate several papers presenting interesting faces of material properties. Most of them, suitable for general or specific applications, disregard the characterization of the material response to the action of various degradation conditions due to energetic transfer onto products. In the cases of polymer materials used in food preservation and handling, medical and pharmaceutical wear, engineering products, and automotive, aircraft, or rail materials, the stability studies provide valuable data for manufacturers and customers and create favorable conditions for the application of heat and radiation sterilizations.The considerable interest on the polyhedral oligomeric silsesquioxane (POSS) hybrids for the extension of the potential application areas of plastics manufacture is inspired by many papers ,2,3 as t1.5) moieties allow the penetration of free radicals into the special structure of POSS. It was previously demonstrated [Among the promising and compatible inorganic fillers, POSS shows a particular cage effect in respect to the fragments resulting from the degradation of polymers because the large holes created by the scission of  on the protection of ethylene-propylene-diene monomer against oxidation are discussed. The expected effects of the present additives are related to the decrease in the oxidation rates, as well as the effective interaction between the coupling powders, whose concern may be characterized by the activation energies and corresponding durabilities. These innovative antioxidant systems consisting of an inorganic compound and natural blends of polyphenols provide an excellent target for the manufacture of ecological nanomaterial products assisted by γ-processing. Their application areas may be broadened over medical wear, food packaging and beverage and drug bottles, toys, gaskets, O-rings and pipes in the food industry, or medical equipment sustained by the prevention of oxidation degradation and a good biocompatibility.The antioxidant activity of algae is commonly demonstrated by their addition in food as the natural component of biological protection. The low irradiation doses less than 1 kGy are usually concerned with the generation of free radicals causing the damage of radiation bio-oxidation . The extThe present results, which illustrate the appropriate prevention of degradation in ethylene-propylene elastomer by polyhedral oligomeric silsesquioxane, complete the previously reported information in the cases of polyurethanes or epoxy resins, as well as extend the studies on the blends consisting of EPDM and hydrogenated acrylonitrile-butadiene rubber  or with Chlorella vulgaris and Spirulinaplatensis were provided by R & D National Institute of Chemistry and Petrochemistry . They were added in the present formulations as the received component. Polyhedral oligomeric silsesquioxane  as vinyl-POSS (Ov-POSS) was purchased from Sigma-Aldrich . Chlorella sp. microalgae in powder form has the following chemical composition (w/w%): fats 11%, of which 2% are saturated forms; carbohydrates 25%, of which sugars are 1%; proteins 56%; and natrium chloride 0.1%, while the powder of Spirulina sp. microalgae contains fats 8%, of which 1% are saturated structures; carbohydrates 13% of which sugars are 2%; proteins 67%; and natrium chloride 1.1%.Raw ethylene-propylene diene monomer was manufactured by LANXESS  as KELTAN 8340/A type, whose diene (5-ethylene-2-norbornene) content was initially 5 phr. The used microalgal extracts of Chlorella vulgaris and Spirulina platensis, or couples of them .The EPDM samples were prepared from the pre-purified elastomer, assuring the elimination of manufacturing additives by the dissolution of neat material in chloroform and the separation of insoluble fraction by filtration through Whatman paper. For the preparation of daughter solutions, the protector powders were individually added. They were obtained by the addition of either vinyl-POSS, 60Co source in air at room temperature. The applied dose rate was 0.6 kGy h−1. The γ-exposure was accomplished by the permanent sample rotation that provides a homogenous irradiation. All the samples were handled in a desiccator for avoiding the action of environmental agents to modify the sample structuring between different stages of investigation.All samples contain two concentrations of vinyl-POSS (1 and 5 phr), while the microalgal extracts have a concentration of 2 phr. From these separate solutions, the liquids were poured into round aluminum trays. The dried, thin pellicles were obtained by solvent evaporation at room temperature. For the accelerated degradation, the samples were γ-exposed in irradiation machinery  equipped with The γ-exposure of samples was accomplished as a proper manner for an accelerated degradation, where the concentration of scission fragments is high enough for reliable experiments of durability.For the evaluation of oxidation degrees two investigation techniques of chemiluminescence were applied. A chemiluminescence spectrometer  was used to characterize the progress of oxidation by isothermal and non-isothermal measurements . The bas−1) were applied. The temperature readings have an average error of ± 0.5 °C. The progress of oxidation can be watched because the CL intensity is proportional with the concentration of peroxyl radicals, the former precursor of oxygenated degradation products [For the isothermal determinations, several temperatures  were selected, considering the convenient oxidation rates. For the non-isothermal determinations, four heating rates . refT is the reference temperature (170 °C) for the evaluation of durability.The evaluation of durability was carried out using the same relationship, where Due to the high reproducibility of CL spectra, only one spectrum was recorded for each composition under foreseen measurement conditions.For the evaluation of faith degree for the experimental measurements, i.e., the CL intensity versus temperature, five experiments for the inflexion point of the oxidation  were done. The found values expressed in °C were: 171, 172, 168, 166, 172. The standard deviation was σ = 3.1.p, was calculated with the Equation (2):im and fm are the initial and final weights of bags containing sample , while om is the weight of empty bag. The polymer mass (im or fm) was reconsidered after the abstraction of fillers contributions from the weight listed on the scale screen.The evaluation of crosslinking levels was conducted by dissolution of soluble fraction contained in polymer phase. This procedure was accomplished by the boiling of copper fabric bags containing polymer hybrids (about 0.2 g each) in toluene in a Soxhlet unit for 24 h. For each point, three bags were processed. The bags were weighted before and after boiling with an analytical scale (error ± 0.1 mg). Each value of insoluble fraction was obtained from three similar samples. The insoluble fraction evaluated with an error of ±0.7%, P(x)/Q(x), the ratio between the scission radiochemical yield, P(x), and crosslinking radiochemical yield, Q(x), and the insoluble fractions (p) figures were converted into sol fraction, S, by their abstraction from unity. From the application of Charlesby-Pinner relationship (Equation (3)) [q0, U2,0, and D are initial crosslinking density, initial degree of polymerization, and irradiation dose (kGy), respectively.For the characterization of the evolution of crosslinking by the values of ion (3)) , the intThe representation of sol values provided the equations of crosslinking from which the slopes were calculated.SEM assay on the Ov-POSS powder was accomplished with a scanning electron microscope SEM Aurega , type field emission. All presented images have the magnification of 20,000.2 [The consequences of radiation processing of ethylene-propylene elastomers are satisfactorily explained by a radical mechanism ,36,37,382 . AccordiThe inorganic structure of Ov-POSS seems to be stable over a large range of degradation conditions. However, this feature of the polyhedral oligomeric silsesquioxane was scarcely investigated . Our SEMThe polymer crosslinking progresses by the contribution of unsaturation existing in vinyl structure of Ov-POSS or in the EPDM macromolecules as the added diene (5-ethylidene 2-nornbornene), where initial concentration in the major component is 5 phr. The hardening of crystals is associated with their damage, by which the break and detachment of crystal small pieces lead to the worsening of stabilization efficiency.The non-isothermal CL spectrum recorded on row POSS powder  indicateAt the irradiation dose of 25 kGy, the maximal dose for sterilization, the oxidation of powder becomes effective at 80 °C, while a higher dose of 100 kGy causes a strike reduction of the debut of oxidation down to 50 °C. At the same time, the corresponding increase of temperatures causing an advanced fragmentation rate is achieved. However, the ESR investigations did not reveal any signal so that we may presume that radical feature of the degradation intermediates of POSS is screened by the vinyl units in an electronic interaction with π bonds. An exponential dependence of the CL intensities on a certain moment of degradation  that validate these hybrids as interesting formulations for the conservation of material integrity and oxidation states. The confirmation of this trend in the delaying of oxidation is addressed , when the oxidation of materials begins to be measurable . The neaow level c, and thThe comparison between the radiation resistances of modified EPDM by the increase in the oxidation strength of γ-irradiated polymer samples orders these formulations in the following order:However, the discrepancy between the protection activities of the two studied microalgal extracts is minimal. Their applications as the agents for oxidation preventing are recommended, as well as the analogous contribution of Ov-POSS.The effect of heating rate on the progress of oxidation in EPDM as an example of polyolefins may be analyzed by the heights of oxidation maximum in the temperature range from 140 °C to 160 °C. The more intense the heat transfer, the higher the CL emission intensity. At the same time, the greater heating rate shifts this maximum toward higher temperatures, which may be explained by the impossibility of degradation fragments to meet suddenly with diffuse oxygen.The non-isothermal spectra recorded during the thermal oxidation of EPDM modified with microalgal extracts also reveals their relevant contributions to the prevention of oxidation at the temperatures exceeding 150 °C . While tChlorella vulgaris, and Spirulinaplatensis act upon oxidation, the slopes of lines describing the evolution of durability are greater than the similar value obtained for pristine polymer.The resistance of EPDM to the thermal oxidation is dependent on the restraining efficiency of additive. The competition between the scission and crosslinking of polymer macromolecules is the factor that determines the occupied place in the two separate groups: degradable or crosslinkable compounds, respectively. The evolution of insoluble content of polymers allows characterizing the stability under γ-irradiation. From The improvement in the material integrity after the action of degradation factors (heat and ionizing radiation) is achieved not only by the inactivation of free radical reactivity but also by the increase in the insoluble fraction, which is responsible by the reconstruction of macromolecules and prevents the diffusion of molecular oxygen that feeds degradation.The degradation of EPDM is a prominent process, where an appropriate compound for the delaying oxidation is absent. The addition of a certain inorganic filler (Ov-POSS) and microalgal extracts proves their prevention potential in respect to oxidative degradation. If the protection mechanisms of Ov-POSS and microalgal extracts are totally different , their cThe stabilization efficiency places the investigated compounds in a certain order, which explains their usefulness for the preservation of product entirety. The highest stability is achieved by means of Ov-POSS (5 phr). A good durability performance is also obtained by the presence of microalgal extracts (2 phr), but this modification has an enormous advantage consisting of their encouraging feature of biocompatibility. The proposed procedure for the manufacture of higher durability of EPDM-based products involves the advantageous effects related to the enlarging the application areas due to the satisfactory consequences on the delaying oxidation, on the maintaining product integrity, on the low costs of item production.The co-operation actions of the two kinds of oxidation protectors are based on the complementary effects that involve two different manners for the inactivation of free radical reactivity in respect to molecular oxygen. If a γ-irradiation processing is applied, the material stability increases accordingly.Microalgae extracts are a potential source for several activities, including the improvement of the applications involving bioactive compounds ,50. The Chlorella vulgaris and Spirulina platensis. They act efficiently on the delay of oxidative degradation by the blocking the reactivity of free radicals. The chemiluminescence determinations, as well as the crosslinking investigation, prove the involvement of these structures in the withdrawing degradation intermediates from their oxidation. While the isothermal CL measurements allow remarking on the increase in the values of oxidation induction time for all modified formulation, except the composition of EPDM samples containing Ov-POSS 1 phr, the non-isothermal CL measurements define the contribution of studied additives to the delaying oxidation by the higher figures of onset oxidation temperatures. These kinds of assays make differences between the two microalgal extracts that show a shoulder at about 100–120 °C and the retarded evolution of oxidation on the higher temperature range. The conclusive proof of protection features is the values set of activation energies required by the degradation of EPDM component, and the increase in the insoluble fraction of γ-irradiated EPDM-based samples undoubtedly sustain the decay of free radicals by recombination, instead of their oxidation. The association of one tested microalgal extract with vinyl-POSS is a profitable solution for the achieving the high-performance stability with which the products may have an extended durability.This paper presents the satisfactory improvement of thermal and radiochemical stabilities by the addition of some appropriate compounds, vinyl-POSS and microalgae: The degree of oxidative degradation in EPDM-based materials is effectively diminished by the two different withdrawing matters: the blocking of radical intermediates inside the free hole of tetrahedral configuration (Ov-POSS) or the scavenging free radicals by the alkoxyl structure of phenolic components of microalgal extracts. The coupling of these stabilization mechanisms offers a proper version of stability improvement for polymer materials.The γ-irradiation assay demonstrates that the proposed solutions for the manufacture of high-performance materials by the presence of Ov-POSS and/or microalgal extracts may be acceptable for the products subjected to γ-processed or γ-sterilized articles.


One principal approach to achieve self-compacting properties is the increased amount of finer constituents of the mixture. This, in turn, increases cement consumption leading to higher greenhouse gas emissions. Pozzolanic materials, like rice husk ash or calcined highly kaolinitic clays, have gained increased attention as supplementary cementitious materials in self-compacting concrete production. These materials could be viable alternative supplementary cementitious materials for sub-Saharan Africa which already lacks fly ash, slag and silica fume. This current effort reviews the impact of rice husk ash and calcined clays for the production of self-compacting concrete. Special focus is on their impact on rheological, mechanical and durability properties of self-compacting concrete. Rice husk ash and, in particular, calcined highly kaolinitic clays are introduced as technical and cost-effective supplementary materials for use in self-compacting. The review disclosed a lack of knowledge when it comes to the use of low-kaolinitic calcined clays as sole SCM or together with rice husk ash, which could be a very promising combination for e.g., several countries in Africa. Further studies are needed on the rheological properties, shrinkage, creep, and durability of self-compacting concrete produced with other calcined common clays and their blend with rice husk ash. The potential of various pozzolanic materials as partial replacements for cement in self-compacting concrete (SCC) production was established in previous studies. In order to continue with the trend of research on the use of rice husk ash (RHA) and metakaolin—one of the calcined clays—as a supplementary cementitious material (SCM) for SCC production, and to point out the missing gaps for further studies, the following review starts with introducing the concept of SCC and the SCM for its production, then a brief overview is given of the characteristics of rice husk ash and calcined clays as pozzolanic SCM. It is followed by a detailed literature study focusing on the fresh, mechanical, and durability properties of SCC with RHA, calcined clays, or a blend of both materials. In reinforced concrete, a sufficient concrete cover usually serves to protect the reinforcement from adverse weather effects, harmful substances, and to improve durability. A dense microstructure can only be achieved if the concrete flows properly and embeds the reinforcement closely, fills all gaps and corners of formwork without any kind of obstruction. To achieve these attributes, concrete that requires very little compaction only was first produced and used in Europe in the early 1970s ,3,4.The flow of SCC, measured as the total spread of the mixture particles purely under the influence of gravity, is normally achieved by controlling the water–powder ratio and applying high range water-reducing admixtures (HRWR) . BesidesSCC can be classified into three types. The powder type: here, the fluidity of SCC is achieved by a reduction in coarser aggregate content and the addition of high-range water reducers. While the segregation resistance is achieved by increasing the percentage of fines ,3,7. ThiThe optimization of mix design towards self-compacting properties leads to superior qualities over conventional, vibrated concrete . The modDespite its technological advantages, the market share of SCC is small due to some obstacles especially in developing countries ,16. FirsMix design of SCC entails either a large reduction of coarse aggregate and an increased powder content ,23 or a 2 release. Right now, it is already hardly available in Africa or South America . Tr. Tr63]. Although, when obtained from an uncontrolled burning, the formation of crystalline silica is possible leading to poor pozzolanic properties and high water and superplasticizer (SP) demand ,70. Ganesanet et al.  observed4) tetrahedral and (AlO6) octahedral sheets that are connected via OH-groups and aluminum cations [Metakaolin (MK), as the most famous representative of calcined clays, is the metaphase of the phyllosilicate kaolinite after calcination. The calcination temperature (500–650 °C) is chosen based on the dehydroxylation temperature of kaolinite. Kaolinite is a 1:1 phyllosilicate consisting of  and plastic viscosity (µ) across the globe have been summarized in the form of rheographs and a workability box by ,102,103.Benaicha et al.  proposedRheological measurements on self-compacting mortar produced with RHA as clinker replacement revealed increased yield stress and viscosity due to an increase in water demand . Ling etAlthough both RHA and MK have good potential to be used as SCM in concrete production due to their superior pozzolanic reactivity, their use as clinker substitute in SCC production results in a significant decrease in slump flow and an increase in viscosity. Consequently, when both materials are to be added to SCC higher dosage of SP is required.RHA addition up to 10 wt.% of binder was found to increase the compressive strength of SCC ,31,106. It becomes clear from Metakaolin can lead to an acceleration of cement hydration and strength development when properly treated and added to cement . An incrTernary blends of RHA and MK were found to improve both early and later compressive strength development in SCC as reported by ,110. A hUltrasonic pulse velocity (UPV) is a proper parameter for testing the homogeneity and integrity of concrete non-destructively. Increased UPV values correspond to the densification in the internal structure of the SCC . Higher Özcan and Kaymak , observeThe mechanism of achieving SCC entails a reduction in size and quantity of coarser aggregate content of the mixture, this raised concern that SCC may have lower values of modulus of elasticity, which in turn will affect the deformation characteristics of the concrete . SeveralShrinkage and creep behavior are important attributes to be studied when introducing any pozzolanic material as SCM. This is related to high water evaporation rates, especially in dry conditions, due to slow hydration kinetics resulting in high free plastic shrinkage compared to SCC without SCMs . So far,Few papers deal with the impact of RHA on shrinkage behavior of SCC ,122. BotWith the addition of MK at 15 wt.%, the drying plastic shrinkage value of SCC increased by about 20 % since MK contributes to the high water evaporation rate of the system and consequently the tendency of higher sensitivity to drying ,127. SCCNesvetaev et al. , studiedSimilarly, a reduction in water absorption of SCC was noticed for all replacement levels  of MK as shown in Sorptivity of SCC produced without the addition of SCMs was found to be very high compared to CVC and was attributed to the higher binder content of SCC . HoweverThe use of RHA (up to a replacement level of 25 wt.% of cement) was found to decrease the porosity of SCC and, thereby, to lower its permeability ,136. ThiThe rapid chloride permeability test (RCP), by passing an electric charge through concrete specimens, is used to assess the chloride penetration resistance of concrete according to  and as well, limits its impact on the dynamic modulus of elasticity of SCC subjected to F-T cycles. The durability factor, determined based on ASTM C 666-15 method of SCC without RHA subjected to up to 300 F-T (+4 to −18 °C and subsequently −18 to +4 °C for 5 h) cycles was found to be 56%. When RHA was used as cement replacement at 15 wt.%, the durability factor increased to 80% . SCC witDuan et al.  observed3, thereby promoting the precipitation of hemi/monocarboaluminate AFm phases of binder hydrates [3, cement) without an adverse effect on its strength and durability. The use of both RHA and metakaolin as a partial replacement for cement increases the water demand of the blended system [Both RHA and metakaolin are pozzolanic and are used as a SCM for SCC production ,32,33,34hydrates ,30,115. d system ,46,123 ad system ,74,75, rMetakaolin was found to be the most commonly used calcined clay for the production of SCC thus far. The suitability of other clayey materials such as calcined clay waste, calcined red mud, and calcined common clays with low kaolinite content for the production of SCC was not yet explored.Rice husk ash and metakaolin are pozzolanic materials and have the potentials to be used as supplementary cementitious materials in self-compacting concrete production. The potentials of rice husk ash as a viscosity-modifying agent in concrete production is also established.Both rice husk ash and metakaolin have high water demand compared to cement. Therefore, their use as a supplementary cementitious material in SCC entails the application of a high dosage of superplasticizers.Rice husk ash was found to be very effective in increasing self-compacting concrete strength due to its high content of reactive amorphous silica and higher specific surface area. Metakaolin, on the other hand, was also found to improve early strength development due to its fast pozzolanic reaction.The optimal replacement level for both the binary blend with RHA and MK is usually between 15 and 20 wt.%. However, with a ternary blend with RHA and MK, larger cement replacements of between 20 to 40 wt.% are possible.Studies on the effect of ternary blends of rice husk ash and metakaolin on shrinkage and creep behavior of SCC were not found by the authors.Although researchers have presented results of the durability of SCC produced with a blend of rice husk ash and metakaolin, there is a need to further study the effect of these materials on porosity, carbonation and freeze-thaw resistance of SCC.The review disclosed a lack of knowledge when it comes to the use of low-kaolinitic calcined clays as sole SCM or together with rice husk ash which could be a very promising combination for e.g., several countries in Africa.Greenhouse gas emissions and environmental problems could be reduced by partially replacing cement with RHA and metakaolin.The following conclusions were drawn from the findings of the study:The effect of RHA on the rheological properties of SCC in terms of yield stress, plastic viscosity, shear-thickening behavior, and workability retention was reported in the literature. However, such detailed studies were not found on a binary blend with calcined common clays nor a ternary blend of RHA and calcined common clay. The fracture mechanism and durability  of SCC produced with RHA and calcined common clays as a partial replacement for cement needs to be further investigated as well.


The demand for natural aggregates (river sand) is increasing day by day, leading to the destruction of the environment, a burden that will be passed on to young people. Further, wastes from various industries are being dumped in landfills, which poses serious environmental problems. In order to ensure sustainability, both the issues mentioned above can be solved by utilizing industrial waste as aggregate replacement in the concrete construction industry. This research is done to find out the results using two substances viz., waste foundry sand (WFS) and coconut shell (CS) substitute for river sand and coarse aggregate. Many researchers have found the maximum benefits of substituted substances used in cement, which has material consistency. This current observation explores these strong waste properties of waste-infused concrete and cement, which experience shrinkage from drying out. The replacement levels for waste foundry sand were varied, between 10%, 20%, and 30%, and for CS, it was 10% and 20%. The experimental outcomes are evident for the strength, which increases by using WFS, whereas the strength decreases by increasing the CS level. The concrete that experiences shrinkage from drying out is included in the waste material, showing a higher magnitude of drying shrinkage than conventional concrete. Concrete is a continuously evolving material used to fulfill the projected civil infrastructure requirements of the 21st century. Sustainability and durability are the desirable characteristics of concrete infrastructure. There is an increasing concern about the use of natural resources and river sand mining for concrete production. The depletion of natural resources for civil infrastructure construction should be reduced and given high precedence by infrastructure designers. Adaption of sustainable construction materials along with durability are grand challenges for current and future civil engineers. Over the past few decades, researchers have experimented with different wastages obtained from industries such as foundry sand, steel slag, copper slag, palm oil clinker, etc., for river sand used as a substitute for concrete. More research was done on the first and third material out of the wastages mentioned above. Foundry sand, a by-product from the metal casting industry, is generated in large quantities and dumped as an environmentally degrading landfill. Foundry sand is more suitable for the replacement of fine aggregate when compared to other industrial wastes, which are fresh as well as hardened substances of cement. Khatib has widely studied this effect .The fresh properties and hardened properties such as slump, compression strength, split tensile strength and flexural strength were found as per IS 516:1959. The experimentation was undergone for the first phase, in which coconut shell was partially replaced for coarse aggregate. The test was then conducted for fresh concrete and hardened concrete. The optimum percentage of replacement was derived. For fresh concrete, a slump test was conducted for various replacement. The tests conducted for hardened concrete are compressive strength, split tensile strength, flexural strength, and modulus of elasticity after 28 days of curing. The following testing methods are explained in detail.The slump cone test is the basic test adopted to examine the fresh concrete property using its consistency. The slump value obtained is used to determine the workability of the fresh mix for further usage. The slump cone test was performed as per IS 1199: 1959. The apparatus consists of a mold with a height of 30 cm and a top and bottom diameter of 10 cm and 20 cm, respectively; along with a tamping rod of 16 mm diameter and 0.6 m long. The mold is filled in four layers by tamping each layer with 25 blows with the rounded end of the tamping rod. In order to measure the slump value, the mold should be cleaned outside and raised immediately after levelling the top surface. After the concrete has subsided, the slump value was measured as the difference of height between the top surface of the mold and the highest point of the specimen. For the shallow condition, the degree of workability was very low and the slump value was minimum. The light reinforced section degree of workability was low and the slump value was between 25 and 75 mm. The heavily reinforced section degree of workability was medium and the slump value was between 75 and 100 mm. The heavily reinforced section without vibration, i.e., Tremie concrete degree of workability was high and slump value was between 100 and 150 mm. The degree of workability of heavy reinforced section was shown in 2 per minute) till the failure of the specimen. The load at which the specimen failed was noted as either failure load or ultimate compressive load. The compressive strength of the specimen was calculated by dividing the failure load or ultimate compressive load by its cross-sectional area. For each mix, three cubes were cast and tested, and the average value was taken as the final compressive strength. The test samples of the compressive strength of concrete and plastic failure or load carrying capacity of compressive strength of concrete is shown in Compressive strength is one of the commonly measured hardened concrete properties, used to depict the ability of the material to carry compressive loads without cracking or deflection. Cubes of size 100 mm × 100 mm × 100 mm were cast as per IS 516:1959 to test the compressive strength of concrete. The cast specimens were placed in a compression testing machine of capacity 200 kN and the load was applied gradually (140 kg/cm2 per minute) until a longitudinal split of the cylinder is observed. The load at which the cylinder splits is taken as the failure load. It is mandatory that at least minimum three specimens should be subjected for every trail and the average strength is taken as the split tensile strength.Although the compressive strength itself is enough to verify the efficiency of the concrete, further confirmations in the opposite directions of responses due to tensile loads should also be checked. Cylindrical specimens of diameter 150 mm and 300 mm length are molded as per IS 516:1959 and subjected to water curing for a period of 28 days. The cylindrical specimens after curing are mounted on the compression testing machine and the load is gradually increased (70 to 140 kg/cm2 per minute min) applied at a spacing of 1/3 of the specimen length. The beams were tested on a standard flexural strength testing machine of minimum capacity 50 kN.Flexural strength represents the load bearing capacity of the concrete prism of size 100 mm × 100 mm × 500 mm cast as per IS 516:1959, subjected to bending due to a two-point load .The first phase of experimentation provides the experimental findings of concrete with coconut shell as a partial replacement of coarse aggregate. A detailed discussion on the fresh and hardened concrete properties of CS concrete was made in order to find the optimum percentage of replacement.The fresh concrete property of the CS concrete is measured using the slump cone test. The conventional concrete shows a slump value of 50 mm, whereas the concrete with 5% of CS shows a decrease in slump value as 47 mm. Further, the slump values of all CS concrete have shown a decrease in slump and the maximum decrease in slump was observed for CS concrete with 25% coconut shell. The slump value obtained for different ratios of CS concrete is provided in 2 value (0.7677), i.e 76.77% accuracy on the developed polynomial equation.The compressive strength of concrete without coconut shell was obtained as 28.3 MPa. With the addition of 5%, 10%, and 15% CS, there is an increase in compressive strength value as 29.5, 30.1, and 31.5, respectively, which is 4.24%, 6.36%, and 11.31% higher than the conventional concrete. The compressive strength value has started decreasing with the further addition of CS by 4.24% and 7.42% for 20% and 25% CS in concrete. The change in variation of compressive strength was plotted as a polynomial function, as shown in The split tensile strength concrete with different percentages of CS was given in 2 value of 0.7591, which means the equation can predict split tensile strength of CS concrete with an accuracy of 75.91.The split tensile strength of concrete without coconut shell was obtained as 2.83 MPa. With the addition of 5%, 10%, and 15% CS, there is an increase in split tensile strength value as 2.89, 2.97, and 3.05, respectively, which is 2.12%, 4.95%, and 7.77% higher than the conventional concrete. The split tensile strength value started decreasing with the further addition of CS by 0.71% and 2.83% for 20% and 25% CS in concrete. The relation between the split tensile strength and percentage of coconut shell was plotted as a polynomial function, as shown in 2 value (0.7069), i.e., a 70.69% accuracy on the developed polynomial equation to predict the flexural strength of CS concrete.The flexural strength of concrete without coconut shell was obtained as 3.88 MPa. With the addition of 5%, 10%, 15%, and 20% CS, there is an increase in flexural strength value as 3.98, 4.12, 4.28, and 3.89, respectively, which is 2.58%, 6.19%, 10.31%, and 0.26% higher than the conventional concrete. The flexural strength value of 25% CS has alone shown a decrease in strength by 1.55%. Flexural strength results have shown a different trend when compared to compressive strength and split tensile strength. The flexural strength concrete with different percentages of CS are given in 2 value of 0.7826, which means the equation can predict the split tensile strength of CS concrete with an accuracy of 78.26.In phase one, the experimental work on the partial replacement of coconut shell with coarse aggregate in concrete was worked out. The results of fresh and hardened properties of concrete were found using a slump cone test, compressive strength, split tensile strength, flexural strength, and modulus of elasticity, and the optimum percentage of replacement for coarse aggregate with CS was found to be 15%. Although the flexural strength decreased for 20% of CS, and as the percentage increase in strength was less, 15% CS concrete was taken as the optimum % replacement following the trend of compressive strength and split tensile strength. The reason behind this is that coconut shell along with the fibers form a layer around the concrete pores, which improves the strength of the concrete. The concrete mixture workability is calculated through the standard slump cone test, subsequently for the second phase of the experimentation, these outcomes can be entered into the above table. A total of 20% CS shows a decreasing trend in strength for all percentages of WFS. 2 value more than 0.9. The high value of R2 indicates that there exists a strong relationship between the percentage addition of WFS and CS with that of the strength values.M13 exhibits a higher flexural strength when compared to other mixes. Only a marginal decrease in flexural strength was found for concrete made with 20% CS and all the values are less than 10%. A linear relationship in the form of y = ax + b is used for fitting the figures with a correlation coefficient RThe compressive strength of concrete calculated for 28 days was analyzed with the flexural strength of concrete. The experimental value of the flexural strength of concrete for 28 days was referred with the values according to IS 456:2000. The values obtained were shown in 2 value (0.94).The second phase of the experimentation of split tensile strength contains various percentages of WFS as well as CS, as shown in This split tensile strength for 10% CS was more in comparison with 20% CS. Similar to compressive strength and flexural strength, there exists a high correlation coefficient for split tensile strength as well, as shown in sh is the drying shrinkage strain (mm/mm), CRi is the initial comparator value of the specimen, CR is the comparator value, and L is the model’s gauge stretch. The drying shrinkage strains were calculated based on the equation below (2).−6 mm/mm.The shrinkage strain values of mix M11 were very close to the CC. Similarly, the percentage variation of strain values for mix M21 are between 2.2% and 3.5% for all ages of curing. The higher shrinkage strain values for M11–M32 mixes were attributed to factors such as the compressibility of aggregates, presence of clay, and excessive humidity of WFS and CS aggregates. Nevertheless, all the mixtures’ shrinkage values stayed within the limit of 800 × 100In phase two of the experimental work, the combination of both foundry sand and coconut shell remains a partial replacement for fine aggregate and coarse aggregate undergone in a concrete mix. The replacement of foundry sand, up to the 30%, remains as a filler in forming void free concrete. Improving the durability and the strength of concrete in a mechanical test was the main goal. As far as coconut shell is concerned, we have already shown in phase one that a 15% replacement shows optimum value. In combination of both coconut shell and foundry sand in same concrete, a 25% replacement of foundry sand and 15% replacement of coconut shell remains the optimum value of replacement of aggregates in concrete ,20,21,22The SEM analysis images are given for four categories. For normal concrete, concrete with coconut shell 15% replacement for coarse aggregate are shown in An increase in the percentage of waste materials in concrete decreases its workability, which is revealed through a slump cone test. The reason behind this could be due to the finer particles of WFS and water absorption of CS;Amalgamation of WFS in concrete increases the strength, whereas the CS inclusion reduces the durability of concrete. Concrete durability is increased by WFS particles, which fills up the void space and makes the concrete denser;The polynomial equations were derived to study the relationship between the percentage of CS and the strength properties. All the strength properties exhibited more than a 70% correlation with the CS%;A linear regression equation was framed to study the different relationship parameters, such as %FS vs. compressive strength, split tensile strength, flexural strength, and also compressive strength vs. flexural strength with high correlation levels (above 90%);The difference between the measured experimental values and the values predicted based on codal equations (IS456) were also studied and compared;−6 mm/mm;At the time of extending wastages in concrete, the drying shrinkage of concrete also increases. Because of excessive humidity of WFS and CS aggregates, the magnitude of drying shrinkage increases. Nevertheless, all the mixtures’ shrinkage values stay within the limit of 800 × 100Through the micro-structural characterization, the reason behind the increase in mechanical properties was found. The addition of CS of more than a certain limit leads to a decrease in the strength properties due to the smooth surface and delamination between the layers of concrete. The addition of FS showed better characteristics than CS concrete. Moreover, CS-FS concrete exhibited superior properties over individual replacements due to the formation of a dense matrix.In summary, the study concludes the following findings:


Published information suggests room for improvement in antibiotics prescribed on discharge from the emergency department (ED). The objective of this study was to evaluate antibiotic prescribing in the ED for uncomplicated infections of the lower respiratory tract (LRTI), urinary tract (UTI), and skin and skin structure (SSTI).≥ 18 years old and uncomplicated LRTI, UTI, or SSTI. Exclusion: hospital admission. Appropriate prescribing was defined having all three of the following correct per local and national guidelines: antibiotic selection, dose, and duration. Correct duration: 5 days for LRTI and SSTI; 3 days for trimethoprim-sulfamethoxazole (TMP-SMX), 5 days for nitrofurantoin (NFT), and 7 days for beta-lactams for UTIs. Endpoints within 7 days: antibiotic escalation, readmission to ED or hospital, any outpatient contact, and report of adverse drug event (ADE). Endpoints within 90 days: Clostridioides difficile infection (CDI). Descriptive and bivariable statistics were performed.IRB-approved retrospective cross-sectional study of patients discharged from the ED from January to June 2019 at 6 locations. Inclusion: Inappropriate prescribing: 77% (304) vs. appropriate 23% (89). Infection type: 47.8% SSTI, 30% UTI, and 22.1% LRTI. SSTI was associated with the greatest proportion of inappropriate prescribing at 89.4% . Comparisons for inappropriate vs. appropriate groups: 15.8% vs. 22.5% for beta-lactam allergy and 23.4% vs. 19.1% for cultures drawn in ED. Most common antibiotics for inappropriate vs. appropriate: first generation cephalosporin at 70.1% vs. 7.3% (p< 0.05), TMP-SMX at 14.3% vs. 12.2% (p=0.75), and NFT at 7.8% vs. 65.9% (p< 0.05). Prescriptions considered inappropriate were primarily driven by excess duration . Endpoints for inappropriate vs. appropriate groups: antibiotic escalation at 6.6% (2.8% were due to cultures drawn in the ED) vs. 1.1% (p=0.06), readmission at 8.6% vs. 9.0% (p=0.9), any outpatient contact at 18.4% vs. 19.1% (p=0.89), and report of ADE at 1.3% vs. 1.1%. No CDI in either group. Figure 1. Appropriateness of Discharge Prescriptions by Infection Type, N = 393Figure 2. Subset Analysis: Reasons for Inappropriate Prescribing, n = 304The main reason for inappropriate prescribing in the ED was excess duration of therapy, making this an area of opportunity for future antibiotic stewardship improvement.Rachel Kenney, PharmD, Medtronic, Inc.  Susan L. Davis, PharmD, Nothing to disclose


The NISC engineering composite exhibits nacreous BM structural similarity, high compressive strength of 68.5 MPa, compress modulus of 42.0 GPa, Mohs hardness of 5.5, Young’s modulus of 41.5 GPa, and shear modulus of 18.4 GPa, higher than pure concrete. More interestingly, the hypervelocity impact tests reveal the penetration capability of our NISC target material is obviously stronger than that of pure concrete, enhanced up to about 46.8% at the striking velocity of 1 km/s and approximately 30.9% at the striking velocity of 2 km/s, respectively, by examining the damages of targets, the trajectories, penetration depths, and residual projectiles. This mechanically integrated enhancement can be attributed to the nacre-like BM structural architecture derived from assembling the special steel-bar array frame-reinforced concrete platelets. This study highlights a key role of nacre-like structure design in promoting the enhanced hypervelocity impact resistance of steel–concrete composites.Steel–concrete (SC) composite widely used in military defensive project is due to its impressive mechanical properties, long-lived service, and low cost. However, the growing use of hypervelocity kinetic weapons in the present war puts forward higher requirements for the anti-explosion and penetration performance of military protection engineering. Here, inspired by the special ‘brick-and-mortar’ (BM) structural feature of natural nacre, we successfully construct a nacre-inspired steel–concrete (NISC) engineering composite with 2510 kg/m However, with the gradual emergence of variously advanced offensive hypersonic weapons (the striking velocity reaches possible up to 2 km/s), the penetration capability and destructive effect of projectiles have been greatly improved. Notably, the impact resistance of traditional reinforced concrete structures such as steel–concrete armours has been not enough to satisfy with the protective requirements of these critical facilities6. Therefore, the exploitation of advanced protective steel–concrete (SC) materials and structures with light weight, robust mechanical performance, and excellent anti-penetration capability has become an important research field7.Concrete composite as one of inorganic materials has key role to society, including in civil building construction, mechanical engineering, and military facilities  structure in nacreous layer comprised of 95 vol.% of platelets of inorganic aragonite (CaCO3) and 5 vol.% of a protein15. The impressive fracture toughness of natural nacre makes it one of the most widely studied biomaterials which can achieve a toughness, orders of magnitude greater than either of its constituents16, and meanwhile, the BM design strategy is a unique inspiration for numerous material scientists. Many researchers’ groups have intelligently utilized the strategy to prepare various nacre-like hybrid composites including long fiber, thin films, and centimeter-sized bulk materials, which even obtain more outstanding mechanical properties compare with those of the nacreous layer22. Therefore, by understanding this advantage in the fascinating spatial structural heterogeneity of natural nacre, it will guide some new high-performance engineering composite materials which can be potentially applied in military facilities and civil building engineering. However, in spite of two decades of research effort, this nacre-inspired strategy mainly focuses on the preparation of small (centimeter)-sized composite materials23. Obviously, large-sized, nacre-inspired composite bulks have wider practical applications in military facilities in comparisons with small-sized composites. With respect to concrete composite materials, although a number of protective SC composite barriers with various structural features have been developed in previous reported works26, there is no example using this nacre-inspired designed strategy to create high anti-penetration performance SC composite architectures.In nature, numerous shock-resistant biomaterials such as mollusk shells, bone, and mammalian tooth enamel comprise primarily some inorganic substances and are used for structural purposesIn this work, inspired by the BM structural feature of natural nacre, we successfully construct large-sized, protective nacre-like steel–concrete (NISC) composite targets with unique macroscopic lamellar architectures. Our approach is based on the precise controlling assembly of steel-bar array frame-reinforced concrete building blocks on a pre-defined process routine to create architected nacreous macrostructure. During the construction process, we solve two critical challenges: developing the mechanically high-performance steel-meshed building blocks and optimizing the enhanced interfacial interactions between the adjacent lamellar building blocks in the NISC structures. Static mechanical tests reveal that our NISC composite materials achieve compressive strength of 68.5 MPa, compress modulus of 42.0 GPa, Mohs hardness of 5.5, Young’s modulus of 41.5 GPa, and shear modulus of 18.4 GPa, greatly higher than the pure concrete. More importantly, based on the hypervelocity impact tests for examining the damages of targets, the trajectories, penetration depths, and residual projectiles, we demonstrate that the anti-penetration capability of our NISC target material is obviously stronger than that of pure concrete, enhanced up to about 46.8% at the striking velocity of 1 km/s and approximately 30.9% at the striking velocity of 2 km/s, respectively. The excellent mechanical combination can be due to the nacre-like BM structural architecture assembled from the special steel-bar array frame-reinforced concrete platelet glued by a soft organic matrix. Predictably, the successful preparation of large-sized, nacre-inspired SC composite materials will guide us to design and construct building construction and facilities satisfying the protective requirements.28. In this work, we copy nacreous structural features to construct a protective NISC composite material that can embody a higher static mechanical properties and more excellent anti-penetration performance. Firstly, a 5 mm-diameter steel-bar array frame as a reinforced phase prepared by the welding process, consisting of sixteen quadrates (7 × 7 cm) on a plane and a rebar array consisted from sixteen steel bars (30 mm height) located at solder junction perpendicular to the frame plane, as shown in Fig. 16. Thirdly, a ~ 5 mm polyurethane polymeric layer is coated on the surface of the steel-bar frame reinforced concrete platelet to form the polymer-coated steel–concrete structural unit. Noticeably, the thickness of nacreous platelet is approximately 0.3–0.5 μm and the deposition of a 20–30 nm protein layer is intercalated aragonite platelets16. Therefore, we designed that the thickness ratio of the SBRC platelet to the polymer layer was 10:1 based on the best optimized thickness ratio of aragonite platelet to organic layer in natural nacre. An important step is to select the polymers with mechanical attributes similar to the interfaces in natural mollusk shell. Several polymers such as methyl silicone resin and polyethylene we tested in tension are too brittle or weak (leading to poor energy absorption) , are successfully obtained by the above assembly technique, named by NISC-100 and NISC-300, respectively.Natural nacre material with highly ordered BM microstructure can inspire a new path to construct some advanced engineering materials with outstanding mechanical properties Fig. , especia27.The whole preparation process of the NISC composite material is simply shown in Fig. x axis) direction in Fig. x axis direction revealed that the NISC composite achieved a better bending resistance capability compared with pure concrete. The maximum Young’s modulus and shear modulus of the NISC composite are clearly enhanced, up to 41.5 GPa and 18.4 GPa, respectively, superior to those of the pure concrete (36.6 ± 4.5 GPa and 15.6 ± 2.0 GPa)  direction, as shown in Fig. x axis direction than those of pure concrete along z axis direction, demonstrating that our NISC material is anisotropic. In this case, the optimal steel–concrete composite achieves an exceptional mechanical combination, which can potentially be utilized as an ideal target material.In addition, we found that, although flexural strength (about 58.3 MPa) of the NISC composite was distinctly higher than that of pure concrete (approximately 35.2 MPa), its Maximum Young’s modulus (about 25.6 MPa) was slightly lower than that of pure concrete (approximately 29.4 MPa), based on the three-point bending tests along the platelet stacking (v = 1 km/s and 2 km), as shown in Figs. 29. To capture the shape and dimensions of the impact craters more precisely, the silicone casting method was used to reconstruct the 3D crater and the projectile trajectory within the pure concrete, as shown in Fig. j-shaped crater followed by a cylindrical tunnel could be clearly observed. And then, typical concrete targets were carefully cut along the penetration boreholes, the sectional views of the typical concrete targets are exhibited in Fig. 30. However, when the striking velocity was enhanced up to 2 km/s, the bullet hole in the pure concrete was obviously broaden, up to about 15 mm. Clearly, the tunneling diameter under was larger than that of the projectile, confirming the assumptions made by several researcher’s groups30. Several large cracks propagated around the bullet hole (these large cracks passed through the whole target), a large area of the surficial concrete around the bullet hole was seriously destroyed. And a heavy damaged state could be observed within the concrete target. These results verified that it wasn’t unaffordable for the common concrete against hypervelocity impacts.The anti-penetration capabilities of the NISC composite targets are then systematically investigated by the hypervelocity impact tests to compare with that of the pure concrete under different striking velocities (v0 = 1 km/s (top) and v0 = 2 km/s (bottom)). Obviously, compared to the unfired projectile, the length and mass of residual projectile reduced a greater or lesser degree. The residual length and mass of 1 km/s recovered projectile  and 2 km/s recovered projectile  are 25.1 mm/5.48 g and 12.3 mm/3.56 g . Also, a ~ 5 cmole Fig. D–I. Alth2 (NISC-100 and NISC-300), 48.55/73.08 mm (NISC-100 and NISC-300), respectively, obviously lower than those of the pure concrete . However, at a striking velocity of 2 km/s, the trajectory depth, penetration depth, residual length and mass of the projectile, impact crater area, and impact crater diameter of the NISC target materials were 102.3 mm (NISC-300), 97 mm (NISC-300), 10/9.11 mm and 2.96/2.72 (NISC-100 and NISC-300), 4018.27/3541.7 mm2 (NISC-100/NISC-300), and 71.53/67.15 mm (NISC-100 and NISC-300), respectively, notably lower than those of the pure concrete . Simultaneously, we also found that the impact parameters of NISC-300 were lower than those NISC-100, suggesting that with increasing of the thickness of the bioinspired target, the impact resistance capability could be gradually enhanced.In addition, to quantitatively estimate the impact resistance capability of the bioinspired composite target, some important parameters  are summarized and compared in Fig. 31. Thus, the static mechanical improvement of a material is benefit to enhance its impact resistance capability to a great extent. Besides, we also account for the discontinuity in rebar when assembling the SBRC platelet. For small sized projectile , the anti-penetration effect is stronger when hitting the rebar frame than that when hitting the concrete matrix. However, for large sized projectile (Ф > 7), we consider that the discontinuity in rebar of the composite target can be ignored.Based on the above static mechanics and anti-penetration capabilities of NISC composites, it is generally confirmed that our nacre-like BM structural design, together with the special steel-bar array frame as a reinforced phase, are synergistically conducive to further enhance the load-bearing and impact resistance capabilities of a concrete material. As for static mechanical tests, compared with the homogeneous structure of the pure concrete, on the one hand, the soft interlayer design generates larger nonlinear deformations over large volumes and show higher fracture toughness, on the other hand, the steel-bar array frame in concrete dramatically achieves higher strength and modulus/stiffness. Therefore, the coeffect of the BM structural design and steel-bar array frame results in the impressive mechanical properties of our NISC composites. Similarly, in terms of the impact tests, the high-performance SBRC platelet resists the hypervelocity impact, in other word, the damage of the one-dimensional impact is mostly confined surrounding steel-bar array frame of the concrete target, and the soft interlayer efficiently absorb the impact energy33. These projectiles were demonstrated to be eroded after the penetration tests, showing that the penetration process entered into the eroding stage for these projectiles/target integrations during the above striking velocity ranges34. Generally, when the striking velocity of a penetration weapon is relatively low , the projectile deformation and failure can be negligible during the whole penetration process, therefore the penetration capability can be predicted through considering the projectile as a rigid body29. However, with respect to our hypervelocity impact tests, the projectile must be blunted and even eroded owing to high pressure generated at the projectile/target interface, resulting in a drastic reduction of projectile penetration performance. Correspondingly, when the initial velocity of projectiles is 1 km/s, the blunted lengths of the recovered projectiles within NISC-100 and NISC-300 are 27.5% and 23.1%, respectively, while the relative mass losses are 14.2% and 13.0%. During the penetration process the projectile must be partially deformed but not eroded. Furthermore, when the initial velocity of projectile is enhanced up to 2 km/s, the blunted lengths and mass loss are visibly exacerbated, reach 62.1% and 65.5%, respectively. The residual length and mass loss of projectile increase and decrease with the rising of striking velocity, respectively. Similarly, during our penetration tests, the projectile occurs a large deformation and serious erosion, which can be considered as eroding projectile penetration. Besides, through comparing penetration depth of pure concrete with that of the NISC target, we reckon that, the penetration resistance capability of the NISC target material can be enhanced up to about ~ 46.8% at the striking velocity of 1 km/s and ~ 30.9% at the striking velocity of 2 km/s, respectively. This large enhancement in the impact resistance of the bioinspired concrete material can be attributed to the co-effect of the special steel-bar framework-reinforced concrete design and nacre-like BM structural architecture.In recent years, many researchers’ groups have performed high strength steel  projectile penetration experiments on concrete targets, in which the strengths of targets of projectiles were ranged from 37.4 MPa to 65.6 MPa, corresponding striking velocities were ranged from 660 to 1225 m/s, respectivelyYp) and target resistance (Rt), can be successfully used in the eroding projectile penetrations into metallic targets, where both projectile strength (Yp) and target resistance (Rt) have explicit analytical expressions36. In recent years, an extended dynamic spherical cavity expansion model (EDCEM) was presented by introducing a hyperbolic yield criterion and Murnaghan the equation of state (EOS) to successfully be applied to predict the one-dimension resistance of concrete-like materials for the one-dimension eroding projectile penetration problem29. However, the eroding penetration model is only validated for concrete-like homogeneous composite materials. For our nacre-like, heterogeneous SC composite materials there is still no available recognized model to predict the penetration depth of projectile under ultra-high velocity impacting tests. Therefore, the eroding penetration model for bioinspired heterogeneous SC composite to ultra-high projectile impact should be developed in the near future.As for theoretically predicting the penetration depth derived from high-speed projectile, Alekseevskii-Tate (A-T) model, as a 1D modified hydrodynamic model considering of contributions of projectile strength  was purchased from Xi’an Qinling Cement Factory. Silver sand (1.6–2.2 mm), high performance water-reducing agents, galvanized iron sheet (Thickness = 1.5 mm), steel bar (R = 8 mm) were purchased from building material market. Methyl silicone resin and curing agent were purchased from Hubei Xinsihai Chemical Co. LTD. Polyethylene (PE) were purchased from Aladdin Chemical Co. LTD. Polyurethane (PU) and curing agent were purchased from Shenzhen Youruiqi Technology Co. LTD. Besides, concrete mixers, cutting machines, forklifts, electric welding, and custom plastic molds were also used to prepare these target materials.To prepare nacre-like steel concrete composite target, we firstly constructed the steel-bars array frame (Size: 280 mm × 280 mm × 25 mm), which is composed of sixteen quadrates (7 cm × 7 cm) on a plane and a rebar array consisted from sixteen steel bars (30 mm height) located at solder junction perpendicular to the frame plane. Secondly, the well-mixed concrete . The working size of the specimens is shown in Table 2 gas is pushed into the sealed vessel by a compressor until to a designed pressure. Next, the value of N2 vessel is opened and the plunger is accelerated in the pump tube which is filled with high-pressure hydrogen gas. At the end of the first-stage pump tube is a conical section, leading down to the second-stage 20 mm caliber launching tube that fires the projectiles. In this conical section, there is a rupture disk with a “ + ” pattern scored into the middle surface. When the hydrogen develops sufficient pressure to burst the scored section of rupture disk, the hydrogen flows through the hole and accelerates the projectiles with sabots located in the second-stage launching tube. After the projectiles are pulled out of the launching tube, the sabots are separated from the projectiles aerodynamically in the separation chamber filled with nitrogen gas (see some detailed process in SI)).As shown in Fig. v is measured from a Photron SA5 high-speed camera placed in the projectile trajectory, as shown in Supplementary Fig. In the target chamber, the targets are placed with their impact surfaces perpendicular to the gun barrel. The striking velocity 3, machining tolerance ± 0.01 mm, and staining treatment. During shooting at a striking velocity of 2 km/s, owing to the relatively large mass of the projectile and the insufficient carrying capacity of the sabots (the elastomer), the projectile would reverse attack the projectile during firing, resulting in substandard incident velocity and even scratching the gun tube. Therefore, a 2 mm × 10 mm titanium alloy gasket is added to reduce the damage of the elastomer. The diameter of the elastomer is 12.65–12.75 mm, so that the total mass of the whole projectile is slightly increased.The projectile with sabots and its dimension parameter are shown in Fig. According to the condition of normal impact, upper support and rear support are provided for the relatively thick target materials, as shown in Supplementary Fig. Supplementary Video 1.Supplementary Video 2.Supplementary Video 3.Supplementary Information.