IntroductionAppropriate antibiotic prescription practices for pharyngitis slow anti-microbial resistance. Unnecessary antibiotic prescribing and non-adherence to practice guidelines remain a clinical problem. The objective of this study was to examine the relationship between group A Streptococcus (GAS) throat culture testing and antibiotic prescriptions at 10 free clinics in the Tampa Bay Area serving the uninsured population.MethodsA retrospective cohort study was conducted using data from patient charts from January 2018 to December 2019. We obtained data regarding a chief complaint related to strep pharyngitis: sore throat, enlarged tonsils, pharyngeal erythema, and/or cervical lymphadenopathy. The frequency and relative proportions of throat swab administration and antibiotic prescription were also analyzed.ResultsOf the 12,005 patients serviced during the study period, 245 (2.0%) reported one or more of the chief complaints related to strep pharyngitis. Of the patients reporting pharyngitis, the mean age was 40.2 years, with 66% being female. Of the patients receiving antibiotics for pharyngitis symptoms, 93 (91.2%) did not receive a throat swab. Patients receiving a throat swab showed a significantly increased odds of antibiotic prescription . Patients reporting symptoms of pharyngitis commonly had other comorbidities, including smoking (14.7%) and diabetes (13.5%).ConclusionThe large proportion of patients receiving antibiotics for pharyngitis symptoms reveals the need for provider counseling on current recommendations of antibiotic prescription practices, which state that a throat swab with a rapid antigen detection test and/or culture should be performed for all patients where bacterial symptoms of rhinorrhea, cough, and/or oral ulcers are present. Another potential area of improvement indicated by this study may be providing additional supplies of throat swabs for these underserved clinics. Further research is needed to understand the root causes of providers' non-compliant prescribing patterns in the free clinics and to assess the role of the uninsured population in reducing anti-microbial resistance. Evidence shows that antibiotic over-prescribing practices lead to increased anti-microbial resistance . Over thOne particular area from which to approach the growing threat of anti-microbial resistance is a prescription of antibiotics for acute upper respiratory infections, particularly streptococcal pharyngitis “sore throats.” In 2012, the Infectious Diseases Society of America (IDSA) released guidelines for the diagnosis of group A Streptococcus (GAS) pharyngitis, which state that throat swab along with a rapid antigen detection test (RADT) and/or culture should be performed for all patients where bacterial symptoms, such as rhinorrhea, cough, oral ulcers, and/or ulcers, are present. Following a negative RADT, children and adolescents should receive a back-up throat culture. This culture is not necessary for adults as there is a low incidence of GAS pharyngitis in the adult population .However, many providers do not follow these antibiotic prescription clinical guidelines. In 2006, Machlin and Carper reported that 22% of children with a chief complaint of sore throat were prescribed an antibiotic prescription before receiving a throat swab . Luo et Our study aims to provide a baseline understanding of how antibiotics are being prescribed in free clinics of the Tampa Bay Area.2 tests for categorical variables; missing values were not included in tests of significance. The association between throat swab completion and antibiotic prescription is presented as an odds ratio (OR) and 95% confidence interval (CI).This retrospective cohort study includes all consecutive uninsured patients served at 10 free clinics in the Tampa Bay area in Florida between January 1, 2018, and December 31, 2019. Free clinics are non-profit organizations that rely on volunteer physicians, students, and staff that usually serve vulnerable, low-income, and uninsured/underinsured patients unable to receive care in the usual outpatient setting. Trained undergraduate and medical students conducted a retrospective chart review to identify patients reporting a sore throat, enlarged tonsils, pharyngeal erythema, and/or cervical lymphadenopathy as a major complaint, whether those patients completed a throat swab, and whether those patients were prescribed an antibiotic. We compared demographics  and comorbidities  between patients who received a throat swab and patients who did not receive a throat swab. To test differences between these two groups, we used Welch’s t-test for numeric variables and χStudy data were collected and managed using REDCap electronic data capture tools hosted at the University of South Florida ,10. DataDuring the study period, 12,005 patients were served across 10 clinics. Of these, 245 (2.0%) patients who reported a sore throat, enlarged tonsils, pharyngeal erythema, and/or cervical lymphadenopathy as a major complaint were included for analysis. Of the 245 patients complaining of a sore throat, 102 (41.6%) were prescribed an antibiotic Table .Dedicated efforts toward antibiotic stewardship can reduce unnecessary prescription of antibiotics and decrease healthcare costs and anti-microbial resistance. Pharyngitis in particular provides a useful lens through which prescription practices can be assessed since this pathology can be viral or bacterial in etiology, with only bacterial etiologies warranting antibiotic treatment. Our study contributes to the available body of literature by assessing the current prescription practices of antibiotics in the Tampa Bay Area's uninsured population. Based on our findings, the prescription of antibiotics was associated with the completion of a throat swab. However, of the cases studied, 91.2% of patients received antibiotics for pharyngitis symptoms without a throat swab, revealing that there is still room for provider counseling on current antibiotic prescription recommendations. Currently, the American Academy of Family Physicians (AAFP) recommends clinicians to use a validated clinical decision calculator  followed by a RADT if clinical decision-making scores indicate. Antibiotics are then only prescribed given positive RADT or high scores . HoweverHowever, compliance with antibiotic prescription clinical guidelines among providers serving the uninsured has not been well-studied in the literature. A study conducted by Sarpong et al. found that uninsured patients use fewer antibiotics than insured patients. They also found that socioeconomic status and racial-ethnic differences can contribute to the difference in prescription practices . This isOne possible reason for the difference in prescription practices of antibiotics to the uninsured is that many uninsured individuals obtain unprescribed antibiotics from other countries or unsound sources within the United States -20. The The most notable limitations of our study were the limited sample size and low overall frequency of throat swab completion. Also, our study was limited in that the methodology did not examine the root causes of non-adherent antibiotic prescribing practices such as lack of patient education on antibiotic prescription practices or providers’ concern about the difficulty of following up with patients after test results are returned. It is also possible that scarce financial resources at these free clinics were a barrier to adequate throat swab supplies or that insufficient training resources were made available to promote provider antibiotic stewardship. Nevertheless, our study illustrates that free clinics need more support to be able to follow appropriate screening guidelines.Our study found that only a small percentage of patients who were prescribed an antibiotic completed a throat swab, inversely correlating antibiotic prescription with a throat swab. The uncommon utilization of throat swabs suggests a need for increased support of free clinics to improve prescription practices. Although these results suggest an inverse relationship between antibiotic prescription and throat swabs, more research should be conducted to assess other factors that may be contributing to antibiotic over-prescription and specific gaps in the uninsured population that create obstacles for the appropriate treatment of pharyngitis in this vulnerable population.


However, there are still certain issues with the dosage and efficiency of nanomaterials. Therefore, in order to establish the current state of knowledge in this field, this review gathers most recent results about the performance of LWC modified with nanomaterials. The review is divided into sections about the influence of nanoparticles on the fresh properties of concrete and their influence on the mechanical and durability characteristics. The paper studies in depth the most common approach to nanomaterials in concrete technology and proposes areas for further development.The use of lightweight concrete (LWC) for structural and non-structural applications has attracted great interest in recent years. The main benefits include reduced deadload of structural elements and generally lower production and transportation costs. However, a decrease in concrete density often leads to a decrease in strength and durability. Typically, concretes are mostly modified with mineral additives such as silica fume or fly ash. Because of the recent developments in nanotechnology, research attention has turned to the possibility of improving concrete properties with nanomaterials, i.e., nano-SiO Waste management is a crucial factor for decreasing environmental contamination. One of the best solutions to minimize this issue is reusing and recycling the materials and by-products from various branches of the industry. A good example of recycling is the production of fly ash (FA), where 19 M tons in 2012 were produced in just one European country—Turkey . It is projected that the amount of FA production could grow by more than 30% by 2020 . Among t3. LWCs can be divided into six density classes, from 800 kg/m3 with a grading of 200 kg upwards [Lightweight concrete (LWC), according to the EN 206-1 , is defi upwards . The use upwards ,11,12. S upwards . There a upwards .2 emissions. It also means a lower specific energy consumption due to the limited use of cement, one of the major carbon dioxide producers [Lightweight aggregate concrete (LWAC), in addition to the above-mentioned advantages, exhibits a lower early-age shrinkage compared with ordinary concrete, caused by the internal curing effect ,16, loweroducers ,21.3 and sufficient mechanical strength for structural applications [In previous decades, lightweight aggregate concrete (LWAC) has been successfully developed and improved. The main interest has been focused on lightweight cementitious composites with a density lower than 1500 kg/mications ,22,23. Eications ,25,26. Lications .2 are emitted during its production process. About 90% of the cumulative energy needed for concrete production is spent during the production of cement [2 and produces additional calcium silicate hydrate (C-S-H) gel. Additional C-S-H gel results in a denser microstructure, which leads to an improvement in the properties of hardened cementitious materials [In order to address the above-mentioned issues and increase the durability of LWAC, researchers have looked towards mineral additives. LWAC can be easily modified by supplementary cementitious materials (SCMs), which can improve the microstructure and thus the overall strength and durability . The conf cement ,30. In tf cement ,32,33. Hf cement  at a micf cement ,36,37. Aaterials ,39.Optimization of the mixture designs of LWCs towards the production of high-performance materials with improved mechanical properties, as well as resistance against aggressive environments, is the main topic of interest for researchers and industry. Lightweight high-performance concrete (LWHPC) elements have a distinctive fine pore structure and overall low porosity that corresponds to an improvement in the mechanical properties and durability ,41. The The permeability of concrete is considered as a representative property related to the overall durability of concrete ,45. BecaLightweight concrete, because of its low density, is also a good insulator; the general scope of the thermal properties of lightweight concrete was summarized by Loudon . He repo3 of cement and a density of 1400 kg/m3. A low density was obtained thanks to use of the expanded clay and expanded glass. The 28-day compressive strength of the concrete reached 24 MPa, which is sufficient for structural applications.Yu et al. investigated the durability of ultra-lightweight concrete composite (ULWC) mixes with the fine LWA that had a low open porosity . They fo3 by substituting the NWA with PET by 30% to 60% of its volume. The corresponding compressive strength at 28 days varied between 9.5 to 25.3 MPa. The former mix had the potential to be used as an insulation material, while the latter could be considered for the production of structural elements.Ling et al.  studied 2, nano-Fe2O3, nano-Al2O3, nano-SiO2, carbon nanotubes/fibers [To date, the incorporation of micro-sized SCMs into LWC has been widely researched. In recent years, there has been growing interest in nano-scale particle applications in LWC technology ,65. Thess/fibers , and zins/fibers . Among as/fibers ,69,70,71s/fibers . Dependis/fibers ; therefoNanosilica is known to be an extremely reactive additive ,77. It aVarious approaches towards the incorporation of NS in cement-based composites have been proposed. These include either the addition of NS in the form of a dry powder or a colloidal suspension. The colloidal form of NS has a much better dispersity compared with the powder, increasing its overall efficiency . At an eAlthough, the effects of nanosilica on the properties of normal-weight cement-based composites have been widely studied and reviewed by many researchers, studies related to the LWC are still limited. To date, there have been several studies reporting the influence of NS on the properties of LWC, but no guidelines or summaries have been proposed. Therefore, this review aimed to fill the gap in the state-of-art and presents the recent developments in the field of modification of LWC with NS, as well as to propose further directions and possible applications for the concrete industry.To date, many studies related to the rheological properties of cement-based composites modified with nanosilica are available ,93,94; h2 particles adsorb partially water molecules, negatively influencing the workability. Water molecules are typically attracted to the NS particles because of their high affinity and high specific surface area. This leads to a state where increasing the w/b ratios decreases the required dosage of SP. At the same time, increasing the w/b ratio results in a decrease in density. For instance, the optimum dosage of SP in a mixture with 1 wt.% NS changed from 9.45 kg/m3 (density of 1910 kg/m3) to 4.05 kg/m3 of SP (density of 1878 kg/m3), while the w/c ratio changed from 0.35 to 0.45. This is because the available free water increased with the increase in the w/c ratio. On the contrary, adding NS  eliminates bleeding and segregation in LWC. This concurred in the findings of Jalal et al. [2 can slightly reduce the frictional forces among the particles and improve packing, which leads to an increase in the accessible lubricating water.Based on the cited articles, it is clear that the superplasticizer dose needs to be increased with the increase in the NS content. A simultaneous decrease in the stabilizer dosages with the increase in NS content was required in order to achieve a reasonable flowability. This is caused by the fact that the viscosity of the fresh mixture would increase with the increment of NS dosage, as shown in l et al. , who stal et al. ,100,101.The V-funnel test, for which the results were presented by Naniz et al. , was useAnother method for testing the rheological properties is the J-ring test, presented in The U-box test is a method used to assess the filling and passing ability of concrete. The test reflects the conditions where the concrete needs to fill a formwork with dense reinforcement. Similar to previously described tests, the majority of mixes containing nanosilica performed worse in the L-Box test. This means that the addition of NS decreased the filling and passing ability. Analysing the results summarized in 3, which can eventually result in a higher cost of produced concrete. With the increase in SP dosages, the total amount of viscosity modifying admixtures (VMA) should be decreased, as it influences the workability in a similar manner to NS. Therefore, various parameters should be taken in account when designing LWCs. The necessary amounts of SP required for maintaining the rheological properties of fresh mix often exceed the optimal and maximal dosage recommended by the manufacturers. Moreover, a high dosage of polycarboxylate (PCE) plasticizer can result in a retardation of the hydration process, which limits its use in prefabricated concrete. Therefore, calorimetric studies should be considered as a supplementary tool to evaluate the combined effect of NS and PCE on the hydration process and setting time of mixtures.The use of increased amounts of NS requires a simultaneous increase in the SP content of up to 22 kg/mTo date, NS was found to have a spectacular effects on the mechanical performance of NWC in early age, as well as its long-term strength. The nucleating effect of silica nanoparticles  results As mentioned above, most research confirms a positive influence of nanosilica on the mechanical properties of concrete. Based on the collected literature data, it was found that the compressive strength of mixes containing NS was higher than the control ones. The effect of the NS content on the strength development of LWC is presented in According to Naniz et al. , replaciSimilar to the compressive strength, the splitting tensile strength and flexural strength of concrete have been improved by the addition of NS . The effSimilarly, Atmaca et al.  reportedAn interesting approach was presented by Vargas et al. . Accordi2 on shrinkage was statistically insignificant. During first 7 days, all the shrinkage curves were almost identical. The difference in the value of shrinkage was visible after 90 days, the average measured total shrinkage increased by 2.2%, 3.9%, and 5.4% for LWAC with ceramsite from Nantong with 1 wt.%, 2 wt.%, and 3 wt.% nano-SiO2 addition, respectively [Whenever the mechanical properties are in consideration it is worth to mention and discuss the aspect of shrinkage. The effect of lightweight aggregate on total shrinkage is well studied. Because of the internal curing effect, LWA helps to reduce the total shrinkage ,110. In ectively . The ratectively . Even smectively .Research presented by Sikora et al.  showed tNanosilica was found to have a substantial effect on the refinement of the pore structure of cement paste; thus, produced NWC is less porous and permeable ,112. HowWhen analysing above-mentioned articles, a common conclusion can be drawn that the NS particles reduce the size of capillary pores and modify the pore structure. According to Atmaca N. et al. , the red2 were more compact than that of the reference LWAC. Similar results were obtained by Elrahman M.A. et al. [2, the border between the paste matrix and the ITZ could not be measured. This, on the other hand, could lead to a water penetration depth that decreased by up to 43% according to Du H. [2 [Another influence of NS on the microstructure of cement composites was reported by Wang X.F. et al. . They fo. et al. . For a cto Du H. . The addDu H. [2 . These pDu H. [2 , resultiAnother often applied method that allows for evaluating the durability of concrete is the ultrasound pulse velocity. Higher velocities obtained from the test indicate that the tested specimen has a low porosity, and thus a potentially higher durability . For insThe study of Du et al.  on the eAs reported by researchers, NS reduces the size of capillary pores, changes the pore structure, and reduces overall sorptivity ,22,72,954). For up to 4 weeks, all of the specimens exhibited comparable expansion (Vargas et al.  evaluatexpansion . AfterwaThe use of nanosilica in LWC refines the pore structure of the cementitious matrix and the ITZ by increasing the formation of C-S-H. This densification of the cementitious matrix leads to a smaller porosity and lower water absorption. Depending on the study, the use of NS led to increases in the compressive strength of lightweight concrete of up to 20%. It is also proven that nanosilica is more efficient than silica fume, even in smaller dosages. It is recommended to limit the amount of nanosilica to maximum of 5 wt.% cement in order to obtain the optimal improvement for all of the properties. On the other hand, it has to be remembered that adding nanosilica to a concrete mixture always decreases the workability and flowability. To maintain workability and flowability, a significant amount of PCE superplasticizer needs to be used, often exceeding manufacturer recommendations about dosage. Even though NS is not a new material and has been studied in recent years, there are still areas that need to be properly investigated, especially regarding its use in lightweight concrete. There were only a few papers where the freeze−thaw resistance or influence of different artificial aggregates were investigated. Intensive investigation needs to be done on all aspects of durability in the context of possible 3D printing with lightweight concrete modified with nanosilica particles.Academic studies should result not only in a theoretical knowledge, but should provide practical and industrial applications. This is why LWCs with NS need to be further investigated, as current knowledge indicates that nanomaterials can be successfully incorporated in concrete prefabrication technology. Based on recent papers, it is already known that LWCs have a different structure, pore system, and mechanical and physical properties, but with addition of NS, all of their disadvantages can be minimalized. What needs to be investigated in the foreseeable future is the scale effect, cost analyses in terms of industrial application, and modification of LWCs with NS to make them suitable for 3D printing. Until now, most of studies have been conducted on standard laboratory samples, which does not reflect the behaviour of mass elements. In many studies the amounts of PCE plasticizers in mixes were significantly increased, which limits the use of these mixes outside the laboratory because of elevated costs. This is why LWCs with NS need to be investigated on a bigger scale with economic evaluation.


Chimneys are structures designed to convey exhaust gases from heating devices to the outside of buildings. The materials from which they are made have a great impact on their fire safety, as well as on the safety of the whole building. As current trends in the construction industry are moving towards improving the environmental impact and fire safety, changes to building materials are constantly being introduced. This also applies to the development of chimney technology, as there is still a recognised need for new solutions when it comes to materials used in the production of chimney systems. This article presents the findings of tests carried out on a chimney made from innovative perlite concrete blocks. Four different perlite concrete blocks that differed in bulk densities were analysed. The obtained results were then compared with widely used leca (lightweight expanded clay aggregate) concrete blocks. The test results confirmed high insulation properties of the perlite concrete block, from which the innovative chimney casing was made. The fire safety level was maintained even in high temperatures that occur during soot fire (1000 °C). These properties were retained despite there being no additional insulation of the flue duct. Even though the thermal load decreased the compressive strength of the chimney blocks, they still displayed sufficient average strength of 4.03 MPa. Additionally, the test results confirmed the possibility of recovering heat from the chimney with the efficiency of 23–30%, which constitutes a considerable increase compared to chimneys made from leca concrete blocks. Chimneys are architectural structures designed to convey exhaust gases from heating devices to the outside of buildings. The materials from which they are made have a great impact on the fire safety of those structures, and of the whole building. The side effect of fuel combustion  is the formation of sediments and soot on the internal walls of the flue. When it comes to solid fuels, the exhaust gases themselves are characterised by high temperatures, often reaching 600 °C. In the event of soot combustion, the temperature inside the chimney reaches over 1000 °C. A considerable part of fires is started due to heat radiation from the chimney onto flammable structural elements of the building. This creates significant threat to the residents of buildings heated by fuel-based equipment. Hence, it is vital that the chimney has the highest possible level of insulation. Ecology is just as important as fire safety. The sole purpose of a traditional chimney is to convey smoke into the atmosphere. These chimneys are usually made of brick, insulated steel pipes, and leca (lightweight expanded clay aggregate) concrete blocks with a ceramic duct insulated with wool. Currently, multi-layered chimneys, where the air layer plays a vital part, are becoming increasingly common. The role of the air layer is to feed air into the combustion chamber. This air receives heat from the flue duct, which decreases the temperature of the casing. Furthermore, when fed into the heating appliance, the heated air increases its efficiency. However, the vast majority of scientific literature is focused on chimneys without air layers.One of the most commonly used chimneys is the double-walled steel chimney, which was thoroughly tested by Leppanen et al. ,2,3 and Brick chimneys have also been analysed for fire safety. Peacock  determinSilcock and Shields  focused Thus far, studies have depicted analyses concerning the effect of high temperatures on the physical properties of lightweight concrete ,23, inclMaraveas et al. ,29 demonAnother aspect of scientific research is the analysis of chimneys aimed at improving the efficiency of heating appliances, e.g., through heat recovery, which has a positive effect on the environment. Such analyses concerning steel combustion air flues used in low temperature gas appliances were described by Czerski et al. ,32.Chimneys with leca concrete casings are insulated with mineral wool whose smouldering decreases the building’s fire safety . Since tThis article presents findings that determine the properties of chimneys with a ceramic duct surrounded by innovative perlite concrete casing, which has not been used in chimney technology before. Special attention has been paid to the effects of perlite concrete block casing and increased thermal insulation on the efficiency of energy recovery and fire safety. The study also includes an analysis of the blocks’ compressive strength before and after soot fire simulation. The purpose of the study was to find a material with optimised parameters of thermal insulation which would prevent the temperature on the casing from exceeding 100 °C during soot fire and guarantee compressive strength greater than the weight of 100 m high chimney column, i.e., 1.14 MPa. This study had never been done by other researchers. Moreover, the above-mentioned analyses take into consideration both fire safety and the ability to recover heat from the chimney’s air space. The findings of the study are compared with the traditional chimney made of leca concrete blocks insulated with mineral wool.The subject of the study presented herein was a chimney system comprised of three layers : (i) iso3, and their compressive strength varies from 3–3.5 MPa [3, its thermal conductivity coefficient λ starts at 0.09 W/m·K, and its strength ranges from 0.7 to 10 MPa [The main study concerns the innovative perlite concrete block, and the findings are compared with the parameters of widely used leca concrete blocks. Although chimneys made of leca concrete blocks are characterised by sufficient resistance to soot fire, they must be coupled with additional layers of insulation. They are also characterised by relatively low insulation when it comes to heat recovery . Their d–3.5 MPa ,34,35. A–3.5 MPa ,34. Expao 10 MPa .The blocks which constitute the casing of the analysed chimney were made from a concrete mix in which perlite was the main insulant. No studies of this type of chimney casing had ever been presented in any publications before. This is why the first parameter that we determined was the thermal conductivity, which is characteristic of a perlite aggregate in its loose unsettled state. In this case, it was 0.057 W/m·K. The characteristics of the physical properties of the aggregate (perlite) prepared by the supplier are presented in 3, characterised in 3 were obtained. The specific amount of perlite as well as the types and specific amounts of chemical admixtures are not presented herein due to the protection of this data by the manufacturer (trade secret). The different densities of the perlite were obtained by using different grain sizes, as well as different operation durations and frequencies of the vibration press. The mixing was done in Sicoma 1125/750  planetary mixer, and the casting and compacting was done with the use of an MFS TYTAN 3 vibration press  for concrete prefabrication.As a result of the initial analysis, four perlite-based concrete mixes (no. 3–6) were selected for further detailed analysis. The samples of perlite concrete blocks were made from concrete mixes composed of: (i) 240 kg CEM 42.5R cement  characterised by faster setting time and high early strength ; (ii) 330 kg of unwashed sand with fraction of 0–2 mm. This fraction is used due to perlite’s grain size (approx. 1 mm) and had been determined as a result of optimising aggregates to obtain proper compaction; (iii) 135–156 litres water; (iv) perlite added in the range of 1–1.2 mThe blocks produced according to the aforementioned method underwent curing in a maturing facility. Thanks to the fact that the curing process took place in a controlled environment, the ambient conditions, i.e., temperature of 35–45 °C and humidity exceeding 95%, could be properly maintained. After 30 days of maturing, the samples were analysed.After determining the perlite’s thermal conductivity in loose state  were removed and their temperatures were measured on two sides. The measurements were taken in a steady state in a custom-made test chamber . The temperature differences measured during the tests were marked as ΔThe strength of the product was tested by compressing corners which had been cut out from the blocks in line with standard EN 12446:2003 . The pro3. The granulate consisted of grains of the following sizes: 0.5 mm (20% of the granulate); 0.2 mm (17.6% of the granulate); 0.1 mm (42.1% of the granulate); 0.063 mm (26.2% of the granulate) and less than 0.063 mm (13.9% of the granulate). The product was characterised by low water absorption and low permeability, and was resistant to soot fire. The duct was characterised by conductivity of 0.5 W/mK [The next layer of the chimney was an isostatic ceramic duct which constituted the flue lining. The lining was made from ceramic granulate with the use of isostatic pressing (pressure of approx. 450–500 bars). The bulk density of the granulate was 121.3 g/dm0.5 W/mK .When analysing the obtained results of the block’s thermal conductivity, it was noted that the perlite concrete samples were characterised by a 20% lower conductivity than the samples containing expanded clay. This lends support to the production of blocks from this type of material. The measurement findings also indicated that the thermal conductivity of the samples decreased significantly along with a decrease of the block’s bulk density .The exhaust duct of the chimney was made from isostatic ceramics and had the diameter of 160 mm. Its air space was 25 mm in its narrowest point. The external dimensions of the block were 360 × 360 mm . The hei3  with foil for the duration of the tests a. Since The test stand used for experimental testing is shown in The appliance used for the experimental testing was a stove prototype with a closed combustion chamber b. The stThe experimental tests made it possible to conclude whether resigning from thermal insulation of a flue duct would affects the functioning of the chimney. Similar ceramic-and-concrete systems have been already studied. However, the flue was additionally insulated with mineral wool, and the block was made of leca concrete . The tesThe tests involved measuring the temperatures of the air and the exhaust, as well as the temperature of the chimney casing. The temperature of the air in the air duct and the temperature of the exhaust were measured with the use of a multi-channel temperature recorder produced by Czach . The velocity of the airflow at the inlet to the stove and the velocity of the exhaust at the outlet of the chimney was measured with flow meter TSI-9555P.After building the stand and sealing it with foil , the mai(Stage 1) Kindling—at this stage, special attention was paid to the ease of fire initiation in the stove. Another important aspect of the observation was obtaining the appropriate chimney draught and air intake to the stove. In order to be sure that the air for combustion was provided from the air duct rather than leaks, the provided air was coloured. Thanks to transparent control points, it was possible to observe the flow of the coloured air and exhaust.(Stage 2) Conditioning—after kindling, for over 2 h the exhaust temperature was maintained at over 150 °C at the outlet of the chimney. This was done in order to warm up the system and to remove moisture from the chimney to stabilise testing conditions.(Stage 3) Main testing—these analyses lasted for over 4 h. During this time, the temperature of the exhaust at the outlet was maintained at 150–285 °C and the readings were taken every 15 min. The fire safety was studied on a 2.6 m high model, in line with standard EN 13063-1:2005+A1:2007 , accordiThe test stand  consisteA); on the circumference of a wooden ring (TB–TJ), and (iii) on the surface of the blocks (TK–TL) at the heights of 0.55 m, 1.10 m, and 1.80 m respectively. The temperature sensor on the surface of the blocks was additionally insulated on the outside with mineral wool, which limited heat radiation and provided less favourable conditions.Temperature sensors were distributed as follows : (i) at The hot exhaust was gradually fed into the chimney for 30 min until obtaining a temperature of 700 °C (testing temperature during simulation of the operation conditions is 100 °C higher than the temperature determined by the manufacturer–T600), as recommended by standard EN 13063–1:2005+A1:2007 . TemperaApart from a high level of insulation, a chimney should also have a proper load-bearing capacity. This is why fire testing was followed by tests of the compressive strength  of perliInformation on the strength of brand-new blocks can be used as reference values. Testing strength after applying fire load to the structure made it possible to conclude whether a block would continue to carry loads safely after a fire. The tests involved analysing 6 blocks from each group . The first set of trials was done on those blocks which had not been subjected to thermal testing. They were treated as reference blocks and marked as 1R–6R. The remaining blocks had been under fire load during thermal testing and they were marked as 1F–6F. PERRIER hydraulic machine with a pressing strength of 2000 kN, equipped with a road transformer converter Ptx 200 made by Peltron, and a precision pressure converter type P-30 made by WIKA. Measurements and data acquisition have been performed by the MGC plus system by Hottinger Baldwin Messtechnik  equipped with an amplification module ML801 B. The load was applied at a speed of 1 kN/s.This part of the tests mainly involved observation of the performance of the air layer while air was fed into the stove in order to ventilate the combustion chamber. The second aspect of this part of the analysis was the evaluation and determination of the efficiency of heat recovery from chimney loss (removed with exhaust). No problems were observed with obtaining the appropriate chimney draught during kindling. The smoke was properly discharged, and subsequent stages of combustion were passed without any problems. It was concluded that the system worked correctly, the air was fed into the stove through the air duct and conveyed into the atmosphere through the ceramic flue. The tests were carried out with the combustion chamber closed and open. Below are photographs of the test , includiThe temperatures of the air fed into the stove and the discharged exhaust were measured . Additio3 of exhaust was flowing through the flue per hour. At the same time, the flow of air through the air space was measured and found to be 0.45 m/s, which means that 0.012 m3 of air was flowing through the air space per hour. The same measurements were repeated with an open damper at the inlet to the stove. At that time, the flow rate in the flue duct increased to 0.98 m/s, which means that 0.043 m3 of exhaust was flowing through the flue per hour. The flow of air through the air space was 1.60 m/s, which means that 0.044 m3 of air was flowing through the air space per hour. After opening the inlet, the temperature increased to 215 °C. The measurements confirm normal flow of the discharged exhaust. At the same time, the amount of air provided to the combustion chamber was sufficient for the purposes of fuel combustion. These results justify the possibility of heat recovery and further analysis of the efficiency of the recovered heat.The flow of the exhaust and air was measured after two hours of testing. The flow measurements were taken when the inlet to the stove was closed and the exhaust temperature at the inlet reached 173 °C. At that time, the flow rate in the flue duct was 0.27 m/s, which means that 0.012 mtη, was determined with the use of the following Equation (1):Based on the obtained results, the thermal efficiency of the chimney The maximum temperature values recorded on the casing of the chimney and on the wooden elements located at distance x = 50 mm from the chimney are presented in Based on the analysis of fire safety, it may be concluded that the tested chimney made from perlite concrete blocks meets significantly higher requirements than standard EN 13063-1:2005+A1:2007 . During The next stage of the tests was a 30-min simulation of soot fire, during which exhaust at a temperature exceeding 1000 °C was fed into the chimney. Again, the limit values of the temperature on the surface of the block and on the wooden elements located 5 cm from the chimney were not exceeded, reaching 67 °C on the block and 29 °C on the wooden structure, respectively. In order to provide even more restrictive conditions, the thermocouple on the block was insulated with mineral wool (which limits cooling due to ambient air–stricter conditions compared to standard conditions). The maximum temperature recorded at that point during fire testing was 86 °C. This confirms the high insulation level, and at the same time the fire safety of the designed chimney even in case of failure due to soot fire in the chimney.The obtained results confirm a higher fire safety level of perlite concrete blocks compared to leca concrete casings commonly used in chimneys. Despite an additional insulation in the form of mineral wool, after 30 min of testing, the temperature of the casings of the chimneys made of leca concrete reached 70 °C, and the temperature of the wooden structure reached 36 °C .The damage to the block after applying test load is shown in The defects created when applying vertical load were observed along the entire internal circumference of each block . The shaFor blocks marked as R (reference), the arithmetic average of compressive strength was 5.53 MPa, and the variability index was determined to be 4%. As for the blocks subjected to fire load (1F–6F), the arithmetic average of compressive strength was 4.03 MPa, and the variability index was determined to be 15%. Both trials were characterised by a variability index lower than 25%, which means that their variability was low.3 [According to standard EN 12446:2003 , the tes3 ,23.The results of the experimental tests of efficiency, fire safety and compressive strength allowed the following conclusions:1. Perlite concrete is an innovative material which has rarely been used in chimney technology. Its application increases the level of insulation and fire safety in comparison with other concretes that have been widely used in chimney technology .2. It is possible to recover more heat from perlite concrete chimneys with an air space than from popular leca concrete chimneys. The recovery efficiency determined in the course of our experimental tests was at least 23%. In the case of a leca concrete chimney, this efficiency is determined at 5.5%.-during fire safety tests in extended operating conditions (exposure to 700 °C with declared temperature of T600) for the duration of 210 min reached 82 °C on the block, and did not exceed 26 °C on the wooden structure located 50 mm away from the chimney,-during soot fire simulation (introduction of exhaust at over 1000 °C to the flue) reached 67 °C on the block, and 29 °C on the wooden structure located 50 mm away from the chimney.3. The use of perlite concrete in the production of a chimney casing and the use of an air space as insulation ensures fire safety even without additional layers of insulation . Maximum temperature:4. Although the perlite concrete block was weakened due to exposure to very high temperatures that can be present in a chimney during a soot fire, it still displayed (over 3 times) higher compressive strength parameters than it is required by applicable standards. Moreover, the lowest value of its compressive strength (3.07 MPa) after subjecting the block to high temperatures is comparable to the average compressive strength declared by the manufacturers of widely used leca concrete blocks (3 MPa). It is worth emphasising that the average compressive strength of the analysed block was approx. 1 MPa higher than that of blocks readily available on the market.5. The lower mass of perlite concrete blocks has a considerable effect on the cost of transport to the construction site. The costs of chimneys with perlite concrete casings are further lowered by the ability to resign from mineral wool. Additionally, in case of application of the air layer in the chimney, resignation from wool insulation increases the chimney’s fire safety. Furthermore, lighter blocks facilitate chimney construction, and the structure of perlite concrete blocks allows easier and more aesthetically pleasing machining compared to leca concrete blocks.


Prosthetic joint infections (PJI) are one of the most serious complication of arthroplasty. The management of PJI needs a multidisciplinary collaboration between orthopaedic surgeon, infectious disease specialist and microbiologist. In France, the management of PJI is organized around reference centres (CRIOACs). Our main objective was to perform an audit through a questionnaire survey based on clinical cases, to evaluate how French physicians manage PJI. Eligible participants were all physicians involved in care of patients presenting a PJI. Physicians could answer individually, or collectively during a multidisciplinary team meeting dedicated to PJI. The survey consisted as three questionnaires organized in a total of six clinical cases.S. aureus pre-operative documentation. One-stage exchange strategy was widely preferred in all clinical cases, with no difference between CRIOACs and other centres. Rifampicin was prescribed for S. aureus PJI, in a situation with (90–92%) or without any prosthesis (70%). There was no consensus for the total antibiotic regimen duration, with prescriptions from six to 12 weeks for a majority of respondents.Answers from the CRIOACs to the three questionnaires were 92, 77, and 53%. Between 32 and 39% of respondents did not administer antibiotic prophylaxis despite positive Surgical strategy for the management of PJI was homogenous with a preference for a one-stage exchange strategy. Medical management was more heterogenous, which reflects the heterogeneity of those infections and difficulties to perform studies with strong conclusions.The online version contains supplementary material available at 10.1186/s12879-021-06075-x. Prosthetic joint infections (PJI) are one of the most serious complication of arthroplasty . Those iOne of the main issues in PJI management is the high heterogeneity of clinical situation: heterogeneity on the localization, on the delay  .In France, in 2008, hospitalization for PJI accounted for 0.2% of all hospitalization . The manOur main objective was to perform an audit through a questionnaire survey based on clinical cases, to evaluate how French physicians declare managing PJI in daily care.(Centre de Référence des Infections Ostéo-Articulaires complexes (CRIOACs)). This CRIOACs network consists of nine reference centres, each coordinating at least two of the 21 associated centres.For PJI management France is organized, since 2008, in a large network of Reference centres specialized in the management of PJI All physicians and hospitals in France can contact one of the CRIOACs, to ask for a patient management advice, or for a patient transfer to a specialized centre. The list of all CRIOACs is available on the ministry of health website .(Société Française de la Hanche et du Genou (SFHG)), 2) National network of research in infectious diseases ), 3) The CRIOAC centers emailing list. All physicians who subscribed to one  emailing list(s) received an invitation email (sent by JC and TF) including information about the study and a link to the online survey. Total number of physicians who received the invitation email is too difficult to establish. Therefore, we estimated the response rate over the number of CRIOACs who answered among the total number of CRIOACs in France (N = 30).Eligible participants were all physicians involved in care of patients presenting a PJI, with no restriction regarding their speciality . We restricted the list to the physicians who subscribed to one of those emailing lists: 1) French society of hip and knee Physicians could answer individually, or collectively during a multidisciplinary team meeting dedicated to PJI (one answer per meeting independently of the number of physicians taking part to the meeting).The survey was divided in three questionnaires sent in a 5 months period. Each questionnaire was divided in three parts: 1) an introduction to characterize the participant(s); 2) the first clinical case; 3) the second clinical case , the second one on February 2019 (invitation sent the 5th of March 2019), and the third one on May 2019 (invitation sent the 20th of May 2019). The three questionnaires were closed on the 30th of June 2019. Reminders for the previous questionnaires were sent in each email invitation. Participation in the survey was voluntary, anonymous and without any financial compensation.All methods were carried out in accordance with the French Comission Nationale de l’informatique et des Libertés (CNIL) guidelines. All protocols were approved by the scientific committee of the French bone and joint infections national reference center network (CRIOAc). Informed consent was obtained from all health-care providers who participate to this survey.Data from thrice surveys were extracted from the SurveyMonkey® platform, imported in an Excel® spread sheet and analysed with the R® software (version 3.5.1). Continuous variables were presented as means (and standard deviations), or as medians (and interquartile ranges) depending on the variable’s distribution. Categorical variables were described as absolute numbers and percentages.Univariate analyses were performed, using fisher exact test or chi square test were needed.All answers were considered. If several physicians from the same institution answered individually (and not as a multidisciplinary team meeting), their answers were weighted to overcome the weight of one reference center compared to the weight of selection bias. For instance, when two physicians from the same institution answered individually, each of their answer weighted for 0.5).p-values presented in the All answers presented in the We sent thrice questionnaires to the three emailing lists detailed in the S. aureus infection , 94% of respondents (50.75/54.25) were not performing a systematic nasal decolonization with mupirocin (without performing anterior nare swab), and 42% (22.75/54.25) were detecting S. aureus from anterior nare swab and treating the carrying patients.In a situation with a patient presenting an history of invasive S. aureus acute arthritis who requires a prosthesis on the same knee (Q1C2), 32% (17.5/54.25) did not administer antibiotic prophylaxis, with no difference between CRIOACs  and other centres , p-value = 0.406. For a patient presenting a late PJI with a positive S. aureus pre-operative needle puncture, in case of 1-stage exchange strategy, 39% (13.5/34.5) did not administer antibiotic prophylaxis, with a significant difference between CRIOACs , and other centres , p-value = 0.023.For a patient with a history of Concerning late PJI , most of respondents chose a 1-stage exchange strategy (72–91%) compared to 2-stage exchange strategy (9–20%) or debridement with removal of mobile components via an open arthrotomy (23%) (Table Concerning early PJI (Q3C1), 94% of respondents (48.5/51.5) chose a debridement with removal of mobile components via an open arthrotomy, 4% (2/51.5) chose a 1-stage exchange strategy, 2% (1/51.5) chose a debridement via an arthroscopy without any removal, and none of the respondents chose a 2-stage exchange strategy.p-value = 1; Q3C2: 5% (1.5/27.5) vs. 22% (2.5/11.5), p-value = 0.562). The 1-stage exchange strategy was more chosen for the S. aureus infections. There was a significant difference between the choice of a 1-stage exchange strategy for a S. aureus PJI and a E. faecalis PJI (p = 0.02), and between a S. aureus and a gram-positive cocci in chains documentation (p = 0.007). However, there was no difference between CRIOAC and non-CRIOAC centres.There was no difference between CRIOACs and other centres to choose between a 1-stage or a 2-stage exchange strategy (Q2C2: 22% (4/18.5) of 2-stage exchange strategy for non CRIOACs vs. 21% (4/19.5) for CRIOACs, Antibiotic impregnated bone cement was used in case of 1-stage or 2-stage exchange strategy  of respondents did not consider this positive puncture to choose post-operative antibiotic therapy.Concerning MSSA bone and joint infection (BJI)/PJI  for a late chronic PJI, after a positive Concerning late PJI with a pre-operative documentation (Q2C2 and Q3C2), most respondents chose a broad-spectrum antibiotic : respondents were giving priority to a regimen associating fluoroquinolone and rifampicin (70–90%) (Table Concerning the prescription of rifampicin for S. aureus PJI (Q2C1), clindamycin was a frequent choice if fluoroquinolone or rifampicin were not available , but the MLSB inducible phenotype was considered , then cotrimoxazole  was the first alternative.For S. agalactiae PJI the use of dual therapy was common . Dual therapy including rifampicin was chosen among 44% (18.5/39.5) of the responders.For Concerning total antibiotic regimen duration: 1) After a 1-stage exchange surgery, total antibiotic regimen duration was for Q2C1: 4–6 weeks , 6–8 weeks , 8–12 weeks , or 6 months ; and for Q3C2: 6 weeks , 8 weeks , or 12 weeks .2) After a 2-stage exchange surgery (Q2C2), total antibiotic regimen duration was 8 weeks  , 10 weeks , or 12 weeks  .3) After a debridement via an arthroscopy without mobile components exchange (Q1C1 and Q3C1), total antibiotic regimen duration varied between 3 weeks and 3 months , 22% of respondents did not consider this positive result to choose the post-operative antibiotic therapy. For a late S. agalactiae PJI, 12% started an antibiotic therapy before surgery, based on the pre-operative needle puncture. Even with the pre-operative identification of a bacteria , 45 and 47% of respondents, added an antibiotic therapy against MRSA to the penicillin therapy. Few studies have compared the microbiologic concordance between pre-operative and per-operative samples. In the work of Goulenok et al., only presented in congress, concordance between both exams was 85% [In case of a positive  was 85% , and in  was 85% . The cho was 85% .p-value = 0.004). However, several works showed that after a PJI treatment, a failure can occur with the same bacteria, or with another one, which enhance the importance of all infections prevention. Giving the functional damages and the financial burden of PJI, from our point of view it seems more prudent to administer antibiotic prophylaxis at the cost of microbiological samples.In two clinical cases (Q1C2 and Q2C1), questions on antibiotic prophylaxis showed that respectively 32 and 39% of respondents did not prescribe antibiotic prophylaxis before performing microbiological sample. The main reason is probably the risk to sterilise microbiological samples. A literature review from Wouthuyzen-Bakker et al. pooled all studies comparing patient with and without antibiotic prophylaxis . In the S. aureus PJI (Q2C1 and Q3C1), with respectively 92 and 90% of respondents who were giving priority to an oral regimen associating fluoroquinolone and rifampicin. The crucial role of rifampicin for PJI treatment has already been demonstrated several times [S. aureus are clear with a high level of evidence (A-I) [B inducible phenotype in S. aureus significantly influence the selection of antibiotics in our survey. However, data regarding clindamycin resistance emergence in such situation in still lacking and a recent report from a French team analysing the outcome of S. aureus BJI with such phenotype treated with clindamycin is reassuring when another antibiotic is associated [S. aureus, cotrimoxazole, clindamycin and fusidic acid are the three drugs chosen after rifampin and fluoroquinolone. This is in accordance with the body evidence of antibiotic diffusion in bone and the accumulation of efficacy data of those drugs for BJI [Rifampicin was preferred in all situation with a al times . Recommes PJI Q2C and Q3C1ce (A-I) . The presociated . Finally for BJI . Despite for BJI  it will S. agalactiae PJI.Despite a significant impact on the outcome  in the lS. aureus PJI, after a 1-stage exchange surgery, American recommendations suggest a total duration of antibiotic regimen of 3 months [In our survey, after a 1-stage exchange surgery, total antibiotic regimen duration was from 6 to 8 weeks , or 12 weeks . After a 2-stage exchange surgery, total antibiotic regimen duration was 8 weeks (including 2 weeks after reimplantation) . After a debridement via an arthroscopy without mobile components exchange (Q3C1) 3 months (68%). A recent literature review by Yen et al., in 2019 analysed 10 studies that compared short-course (4 to 8 weeks) versus long-course (4 weeks to 6 months) antibiotic regimen . It incl3 months . They coOur study is a pilot study. It is original, since it was dedicated to all physicians involved in the management of PJI, and because we distinguished CRIOACs in the management of PJI with other centres, and individual answers with answers during a multidisciplinary meeting dedicated to PJI. The survey was sent through three different emailing lists and therefore touched the utmost concerned physicians. The data were weighted to overcome the selection bias and to avoid large centres to be over-represented.Our work also has some limitations. First, the response rate is hard to evaluate since we do not know precisely how many physicians received the invitation emails. The response rate from the CRIOACs decreased during time . This is probably due weariness, since our survey was spread over few months. Then, the characteristics of the respondents to the third questionnaire were very different to those in the first and second questionnaires. More respondents were answering as individuals, and less respondents were part of CRIOACs.Surgical strategy for the management of PJI with common clinical and bacteriological backgrounds was homogenous with a preference for one-stage strategy. Medical management was more heterogenous with a wide range of duration of post-operative antibiotic duration, or total antibiotic duration. This heterogeneity in medical PJI management reflects the heterogeneity of those infections and difficulties to perform studies with strong conclusions, and therefore to publish high level of evidence recommendations.Additional file 1.Additional file 2.Additional file 3.


This study was conducted to evaluate the flexural performance of hollow core slabs (HCS) incorporating the effect of surface roughness. The HCSs are suitable for long span structures due to reduced self-weight. The specimens were HCS with topping concrete and the variables were cross sectional height and surface roughness. The tests were conducted on simply supported beams under four-point loads. The results showed that specimens with interface roughness applied in the lengthwise direction of members exhibited ductile flexural behavior up to peak load than those with interface roughness applied in the member width direction. Their flexural strength was also higher by 1–7% on average, indicating that they are advantageous in improving structural performance. Society is changing rapidly with the development of technology and information, and the construction industry is exerting efforts to deviate from traditional labor-intensive methods. Against this backdrop, methods and structural systems that make on-site management convenient and minimize the number of on-site tasks have come under the spotlight. Structural members are gradually becoming more simplified and they are expected to be applied to structures in the form of affordable modules.Prestressed concrete hollow core slabs (HCS) are members with reduced self-weight due to the hollow core formed in the center of the cross section, providing enhanced structural efficiency. The HCSs are widely used across Europe and North America because their upper and lower tendons allow them to have flexural performance superior to that of reinforced concrete slabs ,5,6,7,8.However, several factors must be considered when applying the HCS on-site. Since the HCS members are manufactured through extrusion of high strength concrete, which has low slump on a long line bed of 90–180 m, shear reinforcement arrangement is difficult and shear capacity must be assessed in consideration of the thin webs arising from the hollow cores ,12,13,14In previous studies ,20,21,22As such, to evaluate the effect of the interface roughness of HCS with topping concrete on structural performance, this study conducted flexural tests with cross sectional height and interface roughness direction as variables. The experimental results were compared to predictions based on design criteria ,24,25,26crM) of prestressed concrete members that allow cracks to form, including HCS, can be obtained as:Various design codes ,24,25,26nM) of the HCS depends on calculation of the tendon stress (psf). Strain compatibility conditions are used when The nominal flexural strength  has less than the minimum required shear connection and is characterized by a clean contact surface with no suspended particles and an intentionally roughened surface. The second (2) has greater than the minimum required shear connection, a clean contact surface with no suspended particles and a surface that was not intentionally roughened. The third (3) has greater than the minimum required shear connection, a clean contact surface with no suspended particles and a surface that was intentionally roughened and has a depth of approximately 6 mm. The horizontal shear strength of the first and second types is calculated by Equation (5) and that of the third type by Equation (6):As shown in Equation (7), The components for the EC 2  approach3, and absorption rates of 1.07% and 1.10%, respectively.To evaluate the structural performance of the HCS in consideration of topping concrete, two types of concrete used to fabricate topping concrete and HCS specimens were mixed with target design strengths of 27 and 49 MPa, respectively. The coarse aggregates used in the concrete mix were crushed aggregates with a maximum size of 19 mm and crushed sand with a maximum size of 5 mm for fine aggregates. The coarse and fine aggregates had specific gravity values under oven-dry of 2.57 and 2.59 g/cmEighteen concrete cylinders, measuring Φ100 mm × 200 mm, were fabricated for testing to estimate the compressive strength of HCS and topping concrete and the curing was performed under the same conditions as specimens ,28. The To secure the cross-sectional performance expected of the HCS, this study used prestressed strands with diameters (Φ) of 12.7 and 9.5 mm to fabricate the specimens ,30. The h) and interface roughness as variables, as shown in To evaluate the structural performance of the HCS in consideration of topping concrete, the specimens were designed with height (a/d) in the range of 4.65–8.47, which prevented shear failure from occurring before flexural behavior.As shown in To reflect the preferred on-site arrangement in relation to the HCS cross-section, CF200 (CN200) had strands as tendons ,30, withShear reinforcement was not considered for any of the specimens, so as to all the conducting of flexural tests to examine the effect of specimen height and interface roughness on structural performance. When fabricating the specimens, jacking force was set at 65% of the tendon tensile strength. While reinforcement was arranged and integrated before casting topping concrete to ensure continuity of HCS slabs during the on-site application, this study considered only topping concrete in order to evaluate structural performance in relation to interface roughness.As shown in a/d).The load-deflection relationships of the HCS with topping concrete are presented in The experimental results of the HCS with topping concrete are shown in a/d) of 4.65, while the other specimens had a higher ratio of 5.19.For CF320, flexural cracks formed at an average load of 354.8 kN and deflection averaged 5.16 mm. The peak load of CF320 was 595.8 kN on average and the corresponding deflection was 24.56 mm. During the formation of flexural cracks, CC320 and CN320 were under average loads of 382.5 kN and 363.2 kN, and deflections were 5.24 mm and 4.13 mm, respectively. The average peak loads of CC320 and CN320 were 631.2 kN and 633.5 kN, and the deflections were 30.55 mm and 27.20 mm, respectively. Compared to other specimens, as shown in During the formation of flexural cracks, the load and deflection of CF400 averaged 295.5 kN and 6.28 mm, respectively. The load and deflection at peak load were 518.0 kN and 60.49 mm on average. The load and deflection of CN400 during the flexural crack formation were 329.3 kN and 6.20 mm on average, while the same values at peak load averaged 539.9 kN and 58.13 mm, respectively.As shown in a/d), horizontal shear cracks were observed in some CF320 specimens with interface roughness applied in the member width direction, but not in CC320 and CN320 specimens with interface roughness applied in the member length direction.crM) of the H200 series averaged 158.6 kN·m for CF200 and 152.5 kN·m for CN200. The predicted average crack moment was 164.0 kN·m for CF200 and 165.7 kN·m for CN200, which translates to experimental-to-predicted ratios of 0.97 and 0.92, respectively. For the H320 series, the average crack moment values obtained experimentally were 368.1 kN·m and 378.5 kN·m for CF320 and CC320, respectively. The predicted crack moment values were 406.4 kN·m and 390.6 kN·m, translating to experimental-to-predicted ratios of 0.91 and 0.97, respectively. The average experimental and predicted crack moments of CN320 were 376.8 kN·m and 396.8 kN·m, which gives a ratio of 0.95. For the H400 series, the average crack moments based on experimental results were 443.2 kN·m for CF400 and 494.0 kN·m for CN400, and the predicted crack moments were 436.2 kN·m and 446.8 kN·m, respectively. That is, the experimental-to-predicted ratios were 1.02 and 1.11, respectively. The reason why the crack moment ratio of the H200 and H320 series is lower than the H400 series that some cracks bear the initial load.As shown in nM) of the H200 series obtained from experiments was on average 289.3 kN·m for CF200 and 294.5 kN·m for CN200. The predicted nominal flexural strength averaged 272.3 kN·m and 275.1 kN·m, giving ratios of 1.06 and 1.07, respectively. For the H320 series, the experimental nominal flexural strengths were 618.2 kN·m for CF320 and 627.0 kN·m for CC320. The predicted nominal flexural strengths were 632.8 kN·m and 612.1 kN·m, which translate to experimental-to-predicted ratios of 0.98 and 1.03, respectively. The average experimental and predicted nominal flexural strength values of CN320 were 657.3 kN·m and 628.5 kN·m, translating to a ratio of 1.05 on average. For the H400 series, the average nominal flexural strengths based on experiments were 777.1 kN·m for CF400 and 809.9 kN·m for CN400. The predicted nominal flexural strengths were 732.1 kN·m and 749.0 kN·m, which give ratios of 1.06 and 1.08, respectively.As shown in As shown in hv) of each specimen was calculated using horizontal shear force at the interface based on experimental results as shown in Equation (8). Due to the equilibrium of forces, horizontal shear force is the same as the compressive force (C) or tensile force (T) if the interface is in the tensile area in consideration of equivalent stress block depth (a). However, if the interface is in the compressive area, it can be calculated using the compressive force (cC) acting on topping concrete. For most HCS with topping concrete, the interface is likely to be in the tensile area because the equivalent stress block depth coincides with the topping concrete layer.To review the horizontal shear strength of the HCS with topping concrete in relation to interface roughness direction, the horizontal shear strength (As shown in a/d) regardless of interface roughness direction and shape. If the flexural behavior is dominant, it is considered necessary to secure sufficient horizontal shear strength for fully composite.The experimental results showed that the CC series and CN series, with interface roughness achieved by applying grooves in the member length direction, had superior deformation performance, flexural strength, and structural performance compared to the CF series, in which grooves were applied in the member width direction. The application of interface roughness in the lengthwise direction is presumed to facilitate force transfer, but further research should be conducted using diverse variables for more accurate prediction. Another possible direction is to explore methods of evaluating the horizontal shear strength of specimens with interface roughness applied in the lengthwise direction. As shown in To evaluate the structural performance of the HCS with topping concrete, this study conducted flexural tests using the cross-sectional height and interface roughness (length and width directions) as variables. Comparing the experimental results to predictions based on design criteria, the following conclusions were obtained.The HCS with topping concrete exhibited ductile flexural behavior up to the peak load regardless of the cross-sectional height and direction of interface roughness. For the H200 series and H320 series, specimens with interface roughness applied in the member length direction regardless of interface roughness area had deformation higher by about 11–27% at peak load than specimens with interface roughness applied in the width  direction. As such, the peak deflection of the HCS with topping concrete can be improved by applying interface roughness in the length direction of members and increasing the roughness area.Comparing the crack moment and flexural strength of the HCS with topping concrete to predictions based on KCI 2017 and ACI 318-19, the experimental-to-predicted ratios averaged 0.91−1.11 for crack moment and 0.98-1.08 for flexural strength. The predictions were fairly accurate for HCS with topping concrete, regardless of the cross-sectional height and interface roughness. Moreover, the flexural strength values obtained from experiments were higher than the crack moment values by 1.64−1.93 on average, thereby satisfying the requirement of flexural moment having to be at least 1.2 times larger than crack moment in order to induce ductile failure, as specified in KCI 2017 and ACI 318-19.The flexural strength of HCS with topping concrete was about 1–7% higher on average in the CN series, which applied grooves in the length direction of the members, compared to the CF series in which interface roughness was applied in the width direction of the members. When interface roughness is applied in the length direction, the structural performance requirement can be met even if the number of grooves is reduced by about 28%.The horizontal shear strength acting at the interface during the flexural failure, obtained from the interfacial horizontal shear force of HCS with topping concrete, was 1.04 times larger than the horizontal shear strength proposed in the design codes (except EC 2), such as KCI 2017, ACI 318-19, and the PCI Design Handbook. All specimens avoided horizontal shear failure before flexural failure and satisfied the flexural strength requirement. The required horizontal shear strength for composite connections specified in EC 2 is also presumed to have been satisfied, thus satisfying the horizontal shear strength requirement at the interface for composite connections. Further research should be conducted using diverse variables to achieve outstanding structural performance even with interface roughness applied in the lengthwise direction. A more rational method of evaluating horizontal shear strength should be developed, as well.


The publication activity of 38 German general/visceral surgery university departments, documented by first or last authorship from staff surgeons (chief and consultants), was evaluated.The observation period extended from 2007 to 2017 and all PubMed-listed publications were considered. Impact factor (IF) was evaluated through the publishing journal’s 5-year IF in 2016, as was the IF for each individual publication. Ranking was expressed in quartiles.Chirurg, followed by Langenbeck’s Archives of Surgery with 274 (5.8%) publications. Pancreas-related topics led in terms of publication number and IF generated per individual publication.The staff surgeons of the 38 departments comprised 442 surgeons, of which only 351 (79.4%) were active as first or last authors. Four thousand six hundred and ninety-nine publications published in 702 journals were recorded. The four leading departments in publication number published as much as the last 20 departments . The mean of the first (most active) department quartile was 19.6 publications, the second 15.4, the third 11.0, and the last quartile 7.6 per publishing surgeon. The total cumulative impact factor was 14,130. When examining the mean number of publications per publishing surgeons per the 10 year period, the mean of the first quartile was 57.9 cumulative IF, the second 45.0, the third 29.5, and the fourth quartile 17.1. With 352 (7.5%) publications, the most frequently used journal was A significant difference in publication performance of individual departments was apparent that cannot be explained by staff number. This indicates that there are as yet unknown factors responsible for minor publication activity in many university departments. Reputation and funding of university hospital departments increasingly depends on publication performance. Considerable difference in the publication performance of individual departments has been demonstrated by Putzer et al.  in the fThe present study was designed to investigate the publication activity in German university visceral surgery. To enable future comparisons of the different surgical disciplines, the methodology of Schubert et al. , Haffke The publication performance of staff surgeons consisting of the chief and consultants of all 38 German general and visceral surgery university departments was recorded. Staffing was drawn from department websites and the key date for all consideration (staffing and publications) was July 1, 2017, with the observation period spanning 10 years from January 1, 2007. Only staff members listed on the department’s website on July 1st were considered as first or last authors. Staff members who had previously left the department were not considered, so that a snapshot on July 1, 2017 was taken. The total number of publications during the entire period 2007 through 2017 was compiled. Publications were recorded when listed in PubMed (Medline) in the form of original papers and reviews with an abstract. There were no exclusion criteria with regard to the choice of topics by the authors. Comments and answers to inquiries were excluded. For each member of the staff surgeons claiming first or last authorship, all publications fulfilling these requirements were recorded . Duplicate attribution for individual publications from the same department, where first and last authorship were claimed by staff surgeons, was factored out in calculating the department’s total publication number, the total impact factor, publishing journal, and publication focus. If an author changed jobs during the 10-year period, the author's publication output was assigned to the department where the author was employed as of July 1, 2017. In a second step, the journal’s 5-year impact factor (IF) for 2016 was recorded via the “Web of Science” under “Journal Citation Reports,” “Journals by Rank,” or “Select Journals.” Journals unlisted in the “Journal Citation Reports” database or for which a 5-year impact factor for 2016 could not be determined were not considered, nor were Eigenfactor scores taken into consideration.HepatobiliaryColorectal Upper gastrointestinal tract PancreasTransplantation Due to the multitude of surgical fields, a compromise was necessary to determine publication focus. The five most common focal points were:All other fields (including endocrine surgery) were grouped under the heading “other”.The departments were ranked from 1 to 38 according to publication number , total acquired IF, and IF of individual publications. Quartiles were created for each ranked parameter, whereby quartiles 1 and 2 each consisted of 9 departments and quartiles 3 and 4 consisted of 10 departments each. Quartile 1 reflected the greatest, quartile 4 the least publication activity. Since the departments were not uniformly ranked for all four parameters, the quartile in which a department appears is parameter dependent.t test, P < 0.05 being chosen as the level of significance. Correlation between parameters was calculated using the Pearson correlation coefficient (r). Values < 0.3 were interpreted as a weak relationship, between 0.3 and 0.6 as a moderate relationship and > 0.6 as a close relationship, assuming a significance of P < 0.05. The quartiles were examined for differences using the Kruskal–Wallis test and Mann–Whitney U test.Range and interquartile range (IQR) are expressed. Groups were checked for significant differences using Student’s P ≈ 0.50). Larger and smaller departments did not differ significantly in the percentage of their publication-active members.The publication activity of the individual departments is shown in Table According to publication activity, departments were assigned to appropriate quartiles, with quartile 1 as most and quartile 4 as least active. To avoid a bias in benchmarking due to the number of members in the department, the number of publications was calculated per publishing member. Considerable differences between the university departments were apparent Fig.  and B. Tr = 0.762; P < 0.05). A moderate correlation between the number of department members and IF per publication was also apparent .The total (cumulative) impact factor for a total of 4699 publications was 14,130. The generated IF per department ranged from 1906 to 35. The mean cumulative IF per department was 372 . The IF per member ranged from 73.3 to 4.9; the mean was 32.0 (median 29.3) per member. As apparent for the sum of publications, the sum of the cumulative impact factor for a department depended on the number of members (correlation coefficient The mean of the first quartile (most active) for the cumulative IF per member, was 51.5 , the second was 34.6 , the third was 24.2 , and the last was 10.3  Fig. . The leaThe IF span for single publications achieved by a department ranged on average from 4.3 to 1.3. The mean IF per publication was 3.0, the median 2.7. The range of the first quartile was from 4.3 to 3.4 with a mean of 3.7 Fig. .The secoChirurg published most frequently with a C-IF of 210.This was followed by Langenbeck’s Archives of Surgery with 274 (5.8%) publications and a C-IF of 634.9 and the Zentralblatt für Chirurgie with 234 (4.98%) publications and a C-IF of 141. Further information regarding publication frequency is shown in Table The 4699 publications appeared in a total of 702 PubMed-listed journals. No more than 10 publications appeared in 630 (89.7%) journals. In 312 journals (44.4%), only one publication appeared. The 20 most frequently used journals are listed in Table Annals of Surgery took first place in terms of generated IF, with a C-IF of 922 , even though it only ranked fifth according to the number of publications. In terms of both frequency and C-IF, Langenbeck’s Archives of Surgery placed second with a C-IF of 635 . The British Journal of Surgery was third, with a C-IF of 353 , and 15th in number of publications . Although Welsch et al.  has subjr ≈ 0.090, P ≈ 0.591) .Regardless of the parameter , there was considerable difference in department performance. For example, 9 of the 38 departments (1st quartile with the highest number of publications) accounted for approximately 3 times as many publications per member, compared to the last 10 departments (4th quartile) Fig. . Differe91) Fig. . The IF In the present analysis, results were divided into quartiles for benchmarking. Quartiles for each parameter were created separately, meaning that a department in quartile 1 with regard to its publication activity could appear in quartile 2 with respect to IF (and vice versa). Putzer et al. [Significant differences in publication number have also been revealed for German anesthesiology university hospital departments, whereby it was assumed, but not analyzed, that the publication number depended on the number of members in the department . SchwarzDiffering publication activity of academic institutions, such as that shown here for Germany, has also been encountered in other countries. Kahn et al.  undertooThe academic productivity of 75 spine surgery fellowship-programs from 2011 to 2014 in the USA was analyzed by Schoenfeld et al.  The totaGeographic differences in both academic promotion and scholarly productivity was noted by Svider et al.  among acIn their comparison of cardiology, cardiac surgery, and general surgery, Schwarzer et al.  observedThe present investigation has limitations, which have been pointed out in the analysis of publication activity in vascular surgery . Only fiAnother controversial factor applicable to the present investigation is that analogous to previous investigations –5, 7, puIf significant differences in publication performance of the departments examined in the present investigation cannot be explained by size alone, then other reasons must be sought for the disparity. The argument that department members lack time to publish to varying degrees has been negated by Schwarzer et al.  on the gManifold circumstances leading to more or less publication activity are conceivable and may vary from university to university. Different organizational and structural forms can influence the emphasis put on scientific activity. An increasing focus on performance-oriented clinical patient care in Germany, with limited research resources and insufficient promotion of science-supporting structures in surgical departments, may also be responsible for sparse scientific activity and may vary greatly from region to region. The increasing shortage of applicants for new surgical positions could also have some effect on scientific activity. Internationally compared, the high percentage of publication-inactive managing team members could explain the moderate position in terms of population that German general/visceral surgery occupies in PubMed-listed publications. Identification of the problems leading to sparse scientific activity should be the goal of future studies and could be approached by national and international comparison not only with other surgical fields, but also with fields outside surgery.The publication performance of staff surgeons in academic German general/visceral surgery departments, measured in terms of first and last authorship in PubMed-listed publications, show considerable variation that cannot be explained by the number of department members. Comparative analysis of publication performance provides an objective means of reflecting scientific activity. Further national and international comparative studies should be initiated to identify the causes behind disparity in scientific activity in academic medicine.


By means of an Evans diagram, it was possible to estimate the value of the cathodic Tafel constant (cb) to be 180 mV dec−1, and the current limit yielded an limi value of 0.98 µA/cm2. On the other hand, the corrosion potential would lie most likely in the −900 mVAg/AgCl to −1000 mVAg/AgCl range, whilst the bounds for the most probable corrosion rate were 0.61 µA/cm2 to 0.22 µA/cm2. The experiments conducted revealed clear evidence of corrosion-induced pitting that will be assessed in subsequent research.The number of reinforced concrete structures subject to anoxic conditions such as offshore platforms and geological storage facilities is growing steadily. This study explored the behaviour of embedded steel reinforcement corrosion under anoxic conditions in the presence of different chloride concentrations. Corrosion rate values were obtained by three electrochemical techniques: Linear polarization resistance, electrochemical impedance spectroscopy, and chronopotenciometry. The corrosion rate ceiling observed was 0.98 µA/cm Corrosion is the primary cause of shortened reinforced concrete structure service life ,2,3, proThe basic semi-reactions taking place in embedded steel corrosion are iron oxidation and oxygen reduction, as per Equations (1) and (2):In underground/water environments, however, given the low levels of oxygen, the cathodic reaction is more likely to involve water reduction and hydrogen formation (Equation (3)):Ag/AgCl. The inference of such low values is that corrosion is governed cathodically [A number of authors have reported perceptible decay in underwater/ground structures ,12, recoodically ,13.Reinforced concrete corrosion research often resorts to potentiodynamic polarisation tests, which deliver corrosion rates nearly instantaneously.i (µA/cm2) is the net free current density, i.e., the sum of the anodic (ai) and cathodic (ci) components; corri (µA/cm2) is the corrosion current density; V (V) is the steel electric potential; corrE (V) is the free corrosion electric potential; and ab is the anodic and cb (V/dec) the cathodic slope of the Tafel curve. Anodic current is conventionally deemed to be positive and cathodic negative.The parameters most commonly yielded in polarisation tests are corrosion potential and corrosion current density. In processes involving polarisation activation only, corrosion current density can be related to the potentiostat-measured current density with the following expression, known as the Butler–Volmer equation (Equation (4)):The table shows results obtained on mortar or concrete specimens ,24,25,26Many authors claim that the corrosion rate of steel under low oxygen conditions is less than 10 µm/year. This measure has been corroborated by several studies. For example, Taniguchi et al.  reported3 cubic concrete specimens prepared with type I 42.5R cement, batched at 350 kg of cement per m3 of concrete. The aggregate dosage per m3 of concrete was AF-0/4 766.00 kg/m3, AG-4/12 823.60 kg/m3, and AG-12/20 325.60 kg/m3, whilst the water/cement ratio was 0.45. The mixing water used contained chlorides in the form of sodium chloride (NaCl) at concentrations ranging from 0% to 2%, referred to cement weight. Specimens E01 and E02 had no chloride in the mixing water, whilst specimens E11 and E12 bore 1 wt% Cl- and E21 and E22 2 wt% of the ion. Duplicate specimens were prepared of all the materials. The tests were conducted on six 10 × 10 × 10 cm2.All specimens were fitted with a 6 mm B500SD steel bar. The photo in 2.After curing in a humidity chamber for 1 d, the specimens were removed from the moulds and placed in a 30 g/L NaCl solution to conduct the electrochemical tests. The entire assembly was stored in a glovebox where the oxygen was displaced by flowing nitrogen. The glovebox oxygen content was determined indirectly by measuring COAg/AgCl and −850 mVAg/AgCl [The oxygen concentration in the glovebox atmosphere was less than 1% throughout the experiment. Such a low oxygen content was verified with chronoamperometric readings at potentials of −750 mVVAg/AgCl . The resRp) values from which corrosion rate can be calculated. The EIS and CP findings can also be used to determine the resistance drop (ΩR) value. All the readings were recorded on a Metrohm Autolab PGSTAT204 potentiostat/galvanostat. In the electrochemical cell used, saturated concrete was the medium, a steel bar the working electrode, stainless steel mesh the auxiliary electrode, and saturated Ag/AgCl solution the reference electrode. The electrochemical readings were logged over 232 days on duplicate samples.Three techniques were deployed to assess specimen electrochemical behaviour: linear polarisation resistance (LPR); electrochemical impedance spectroscopy (EIS); and chronopotentiometry (CP). All three measure the open circuit corrosion potential (OCP) and polarisation resistance (LPR) and subsequently to calculate the corrosion rate [Rp was taken as the slope on the electric potential—cell current (minus the resistance drop) curve  curve . Corrosiequation :(5)icorred steel  and A isEIS consists of applying an electric potential of varying frequency to an electrochemical cell and measuring the complex field of the resulting current. The present study applied 37 frequencies ranging from 1 kHz to 5 mHz with an amplitude of 0.010 V ,21. The −5 A and the resulting potential is monitored. Here, the linear polarisation resistance was calculated assuming the response to fit the curve for the equivalent circuit shown in In this test, current is pulsed through the cell at an intensity of 2.0 × 10This potentiodynamic electrochemical technique delivers current density across a wide range of potentials. Cyclic polarization can be used to find the Tafel slope as well as steel corrosion, pitting, and passivation rates. Here, the range defined was −1.2 V to 0.8 V, scanned at a rate of 0.1667 mV/s. Cyclic polarization tests were performed on all samples under anoxic conditions at the end of the corrosion tests.After the electrochemical tests, concrete specimens were broken to visualise the surface condition of the steel bars under an Olympus SZ261 trinocular stereomicroscope.corri) for specimen E21 under anoxic conditions over a total of 232 days. The values calculated from all three techniques used in the study are plotted . As the figure shows, the findings were very similar for all three techniques and most lay within the shaded area bounded by double and half the mean corrosion rate.2 [corri > 0.2 μA/cm2) and passive (corri < 0.2 μA/cm2) behaviour were observed to alternate in the specimens studied, irrespective of the chloride content in the mixing water.The threshold corrosion current density established to distinguish between activated and passivated concrete-embedded steel is 0.2 µA/cm2 . Periods2 activation threshold for concrete-embedded steel.The corrosion rate over time plots in Ag/AgCl. Moreover, during much of the test time, potentials were below −350 mVAg/AgCl, the threshold for distinguishing between passivated and activated concrete-embedded steel. Under the anoxic conditions used here, however, due to the change in the cathodic reaction and H2 release [Ag/AgCl. The experimental findings for specimen E21 are given by way of example, for all the specimens tested exhibited similar behaviour throughout the test period.The mean of the three corrosion rates found with the techniques described and the mean corrosion potentials  are graphed in  release ,8, the s2 are shown without colour. Only the specimens with no chloride in the mixing water exhibited passive behaviour at the outset. Although the timing differed, given the intermittent activation and passivation observed for the three groups, their behaviour was deemed not to differ substantially.The time intervals when the specimens were active and passive graphed in corrP) assuming uniform corrosion [FeW is the molecular weight of Fe, n the number of electrons transferred, F the Faraday constant, and ρ is iron density.Section loss  observed was −250 mV.Polarisation curves were found for the 232-day-old specimens while still in an anoxic environment to study their liability to pitting and to determine the experimental Tafel slope values. One of the potentiodynamic curves plotted for a scanning range of −1.2 V to 0.8 V is shown in terature ,26,29. Aterature , for theAfter the electrochemical tests, concrete specimens were broken to visualise the surface. As the example in The Evans diagram in limi:Mathematical calculations were performed to fit all the data to a Tafel curve, factoring in the effect of the current limit, cb was calculated to be 180 mV dec−1, a value consistent with those reported in the literature [limi, was 0.98 µA/cm2. Most of the values lay in the interval bounded by double and half the fitted curve values. Many of those that did not lie in that interval were obtained at early test ages when the concrete contained small amounts of oxygen due to specimen preparation.The cathodic Tafel constant terature ,26,29 anConcrete resistivity measurements made in an anoxic environment in all the specimens with the Wenner method ,31,32,33x’ axis, potential on the ‘y’ axis, and the number of measurements recorded on the ‘z’ axis. As the figure shows, irrespective of the chloride content in the concrete, the potential was most likely to lie in the −900 mVAg/AgCl to −1000 mVAg/AgCl range. The bounds for the most probable corrosion rate, in turn, were 0.61 µA/cm2 to 0.22 µA/cm2 or equivalently, 7.0 µm/year to 2.6 µm/year. Normalising the values in An analysis of the empirical data, assuming all formed part of a single population, yielded the distribution shown in Rp values obtained with the three techniques denoted high reproducibility. Under anoxic conditions, the potentials measured were less than −350 mVAg/AgCl practically throughout the test, even when the corrosion rate exhibited presumably passive values.The similarity among the Under the working conditions used here, the steel was not permanently passivated. The corrosion rate, however, was independent of the chlorides present in the concrete. There are small differences that are not significant to distinguish this effect.limi value of 0.98 µA/cm2. At 180 mV dec−1, the cathodic Tafel constant (cb) found is consistent with the values reported in the literature and the mean values obtained from the polarisation curve.Graphed on an Evans-type diagram, the experimental findings used to calculate the current limit yielded an Ag/AgCl to −1000 mVAg/AgCl range, whilst the bounds for the most probable corrosion rate were 0.61 µA/cm2 to 0.22 µA/cm2.The mathematical formula applied to fit the data established the theoretical values for estimating corrosion rate, affording a fuller understanding of structural durability in anoxic environments. The same formula showed that irrespective of the concrete chloride content, the potential would lie most likely in the −900 mVAlthough corrosion was assumed here to be uniform for the intents and purposes of corrosion depth calculations, the experiments conducted revealed clear evidence of corrosion-induced pitting that will be assessed in subsequent research.