Public resources to answer pertinent research questions about the impact of illness and treatment on people with mental health problems are limited. To target funds effectively and efficiently and maximize the health benefits to populations, prioritizing research areas is needed. Research agendas are generally driven by researcher and funder priorities, however, there is growing recognition of the need to include user‐defined research priorities to make research more relevant, needs‐based and efficient.To gain consensus on top priorities for research into early intervention in psychosis through a robust, democratic process for prioritization enlisting the views of key stakeholders including users, carers and healthcare professionals. We also sought to determine which user‐prioritized questions were supported by scientific evidence.We used a modified nominal group technique to gain consensus on unanswered questions that were obtained by survey and ranked at successive stages by a steering group comprising users, carer representatives and clinicians from relevant disciplines and stakeholder bodies. We checked each question posed in the survey was unanswered in research by reviewing evidence in five databases .Two hundred and eighty‐three questions were submitted by 207 people. After checking for relevance, reframing and examining for duplicates, 258 questions remained. We gained consensus on 10 priority questions; these largely represented themes around access and engagement, information needs before and after treatment acceptance, and the influence of service‐user (SU) priorities and beliefs on treatment choices and effectiveness. A recovery SUtheme identified specific self‐management questions and more globally, a need to fully identify factors that impact recovery.Published research findings indicated that the priorities of service users, carers and healthcare professionals were aligned with researchers' and funders' priorities in some areas and misaligned in others providing vital opportunities to develop research agendas that more closely reflect users' needs.Initial results were presented at stakeholder workshops which included service‐users, carers, health professionals and researchers during a consensus workshop to prioritize research questions and allow the opportunity for feedback. Patient and public representatives formed part of the steering group and were consulted regularly during the research process. Research agendas are typically agreed upon at strategic levels by government officials and experts. Few strategic research plans exemplify community participation and the criteria and mechanisms that guide how decisions are made lack transparency.Uncertainty can influence patient outcomes across all areas of decision‐making in mental health including assessing intake acceptance, assigning diagnoses, attributing causal explanations and treatment and care planning.Researchers are beginning to acknowledge that scientifically important questions may not be directly relevant to patientsThe aim of this project was to generate a set of user‐identified research priorities for individuals in the early phase of psychosis. This is a fertile area of research. The development of specialist research units, regional, pan‐continental, and international networks, field‐specific conferences, journals and citation indices evidence this. Some researchers argue that bringing research interest and priorities closer to the need and demand for services is essential to identify and prioritize gaps in knowledge,2Using mixed methods, we systematically identified and prioritized unanswered questions in early psychosis research. We implemented a staged process of surveying to gather priorities, systematic literature searches to determine unanswered questions and a modified nominal group workshop to determine priorities. Our methods were informed by the recommendations of Chalmers et al.2.1http://www.vip.bmh.manchester.ac.uk/).The steering group (VIP‐SG) was established to shape the survey question and design the survey, determine the scope of the project and comment on the processes and procedures for identifying, ranking, and prioritizing uncertainties, agreeing on methods and providing expertise in gaining final consensus. The VIP‐SG comprised service user representatives, clinical representatives, information specialists, leadership and administrative support. Representatives were selected for their involvement with relevant professional groups to represent multiple professional disciplines, user–researcher involvement, and user and carer representation.We identified key themes among relevant policies, guidelines and performance targets as a starting point for discussions around the scope of the project, initially asking the group to consider the appropriateness of the themes and generate further discussion. These included the Mental Health Programme Implementation Guide 2001,2.2Responses to questions were gathered during two phases of the survey and these were delivered online on both occasions. We piloted the survey in the first phase to identify any implementation issues and ensure high‐quality data. The Phase 1 survey was developed by the VIP‐SG adopting a comprehensive approach to generating uncertainties reflecting the wide‐ranging research areas within EI. These included all aspects of illness, recovery, and treatment given that psychotic illnesses are complex, and outcomes of psychosis and subthreshold illnesses framed in a transdiagnostic framework are heterogeneous. Questions were developed in six themes covering community engagement, recovery, treatment refractoriness, effective interventions, EI and physical health improvement . The first author reviewed submissions twice, initially developing indicative questions and on the second review developing and assigning each question to a theme and subtheme which were used to organize the data and identify duplicates. Indicative questions were developed where there were multiple questions with similar meanings and these were assigned red, amber and green classifications based on the degree of confidence held by the researcher regarding how accurately the question retained its intended meaning based on the participants' submission. A consensus meeting between L. R. and R. L. M. was held to determine iterative questions and questions, not in remit which was removed, for example, questions out of scope, philosophical questions not answerable by research and basic research. Iterative questions are determined following an iterative process of refining the questions and the purpose was twofold; we aimed to refine questions to ensure they were researchable and answerable and to ensure that we retained the meaning of each question posed, whether framed in commentary or question, to the greatest extent possible. When respondents asked about NHS service access we considered an effectiveness question to precede this, that is, if a question asked about cognitive behavioural therapy (CBT) access we included a question about whether CBT was effective. Other examples include home treatment, routine physical health screening, public and targeted education, self‐management and supported employment. The iterative process of refining and reformulating questions was based on the agreement between two researchers (L. R. and R. L. M.). See Table 2.4The search strategy was developed by an information specialist (O. S.) consulting with the wider specialist library team at Central Manchester Foundation NHS Trust and the first author (L. R.). For each question a systematic search of the literature was conducted in Medline, EMBASE, Cinahl, PsycINFO, Cochrane Database of Systematic Reviews and the Cochrane Controlled Register of Trials (CENTRAL) where applicable. Specific search strategies were developed for each database and for each question, using a combination of keywords and MeSH/Map terms to include the following: ‘psychosis’, ‘first‐episode psychosis’, ‘early intervention’ and question‐specific keywords. No limits were set on the publication date and level 1 evidence was retrieved comprising systematic reviews, meta‐analyses or qualitative metasyntheses . We included reviews that focused on psychosis and schizophrenia spectrum diagnoses to extract information about first‐episode illnesses if available. Searches were conducted by a team of five information specialists at Manchester Royal Infirmary Library at Central Manchester Foundation Trust and Wythenshawe Academy Library at University Hospital of South Manchester NHS Foundation Trust between February and May 2018. In addition, representatives from VIP‐SG were asked to contribute papers they believed were relevant to answering the questions we obtained. L. R. checked the results and supplemented them with known systematic reviews that were not obtained during searches where available. The search results were analysed and evidence summaries were developed for each question where available and a question was considered to have met the certainty criterion if a systematic review concluded that there was sufficient evidence to answer the question.2.5All questions taken forward to prioritization were ranked in order of the 30 most important questions via an online survey by each VIP‐SG member and these were collated to develop a shortlist of priorities among treatment and illness uncertainties. VIP‐SG members, patients and carers were then recruited to participate in the final prioritization workshop using a modified nominal group technique. Attendees ordered the organization of questions where necessary, voted on their priorities among similarly themed questions and gained consensus on final priorities through small‐group discussions. The final 10 were agreed upon by the entire group during the consensus workshop which comprised service‐users, carers, healthcare professionals, advocates and researchers. Each member was allocated equal voting weight.2.6We adhered to ethical principles contained in organizational policies, but no identifying personal data were obtained and approval by University Research Ethics Committee was not required.33.1Two hundred and seven people answered all or part of the free‐text surveys; there were 80 responses to the Phase 1 survey and 137 responses to the Phase 2 survey. See Table 3.2It took 248 h of librarian time to conduct searches of the databases against the iterative questions comprising over 1000 searches. Relevant systematic reviews were returned in searches for 52 (18.4%) of the iterative questions and the number of available reviews for each question that had a review ranged from 1 to 10 reviews with varying degrees of evidence provided in each review. There were several areas where the evidence was extensive and robust which were also equivocal given the nature of the question posed, for example, no outcome identified, too broad to consider the findings to answer the question wholly or not first‐episode specific. These areas were the effect of lifestyle and diet interventions, the effect of public education campaigns on enhancing awareness, increasing help‐seeking and reducing the duration of untreated psychosis, the effect of family interventions, the effect of interventions to promote occupation, labour force participation, recreation and social network enhancement, prevention of psychosis, tailored interventions to manage weight gain, the effect of psychological interventions and cognitive remediation, influence of cannabis use and causal mechanisms in psychosis. There were reviews that gathered data on schizophrenia, but conclusions could not be drawn about the first episode or the early phase of illness, for example, managing sexual risk and safety, the effect of home‐based treatment and the long‐term effect of novel pharmacological treatments at this stage of illness. There were several qualitative metasyntheses exploring views about medication effectiveness, choice and lifestyle interventions, positive aspects of psychotic experiences, and the role of social support and networks during early psychosis. None of the systematic reviews reported a conclusive answer and we brought forward all questions for prioritization.n = 4), caregivers/family members (n = 4), clinicians/clinical leads (n = 8), policy administrators (n = 1) and educators (n = 2). See Table From 258 priority questions, there were 237 that were endorsed at least once by members of the steering group. Members of the group ranked their top 30 priority questions and once collated, we took forward 42 questions for final prioritization; included questions were endorsed four or more times. The final consensus workshop was attended by service‐users (tors n =  and educ4A final list of 10 priorities was obtained by consensus agreement by stakeholders comprising users of EI services and clinicians and can be considered an important record of user‐defined uncertainties providing intelligence concerning unanswered questions fundamental to the EI paradigm. Knowledge of uncertainties and unanswered questions is a necessary foundation for identifying future directions in research and can support international research efforts towards advancing early psychosis care and treatment. A key uncertainty involved preventing delays and promoting access to treatment and few reviews focused on this despite its centrality to the EI paradigm. Remarkably few studies examined the needs of users for information before gaining access to treatment or school‐based programmes to detect emerging psychosis. Meta‐analytic and narrative reviews emerged evaluating complex, multifocal interventions, discrete professional and patient levels initiatives and different service configurations for shortening delays in accessing care.Prioritizing reducing delays aligns strongly with national research strategy and frameworks recommending a focus on prevention, earlier detection and treatment of mental illnessThe top 10 emphasized an absence of evidence for interventions to enhance community participation and increase users' ability to self‐manage. Reviews obtained in searches largely dealt with recovery using researcher‐defined outcomes.Indeed, a prominent question considered by the consensus group asked specifically about how research funding decisions were made, this question was not retained in the final 10 but captures the essence of this project in that ultimately these priorities will be used by funders and researchers to identify future research priorities and carve out strategic pathways to conduct research of relevance to service users, carers and healthcare professionals. Prioritization is only of value if research follows5This project was a substantial group effort from the VIP‐SG to engage relevant stakeholders in identifying priorities. Targeted activities such as stakeholder review with collaborative networks for applied research, engagement and presentation to user involvement groups, service‐user research groups and charities, and a strong online and social media presence have been a successful strategy eliciting pertinent questions from interested groups. Many questions posed were specific to the field and while relevant, iterative questions tended towards questioning the effectiveness, value and availability of general mental healthcare and treatment.To promote nontokenistic involvement, efforts need to be taken to curb power imbalance and ensure active involvement from service users in mixed stakeholder groups.Lastly, methodologies used to obtain evidence to answer user‐defined questions were predominantly articulated through an experience or values‐based lens before identifying iterative questions. A qualitative inquiry may be best suited to answering these questions but is misaligned with the level 1 evidence that is sought to determine whether there is sufficient evidence in support of particular questions. Among the available level 1 evidence, methods for determining whether a question is answered or not can be subjective and available methodologies require greater scientific consideration as well as an understanding of the necessity for this in user‐defined priorities. In terms of including qualitative evidence, including metasyntheses may mitigate against the mismatch between the available evidence and user‐identified priorities somewhat as there is an increasing acceptance of these synthesis methods in healthcare decision‐making.6Service‐user, carer and healthcare professional defined priorities focused on enhancing evidence for increasing community participation, ability to self‐manage and promoting recovery in daily life. Published research findings indicated that the priorities of service users, carers and healthcare professionals were aligned with researchers and funders in some areas and misaligned in others providing vital opportunities to develop research agendas that more closely reflect users' needs.Laoise Renwick drafted the manuscript. Laoise Renwick was responsible for the organization and preparation of the manuscript. Laoise Renwick was responsible for the concept of the priority‐setting exercise in collaboration with Rebecca Lauren Morris. Olivia Schaff devised the search strategy, and Olivia Schaff and Laoise Renwick at the Trust conducted the searches. Caitlin McWilliams and Susan Ramsdale assisted with project management. Laoise Renwick and Rebecca Lauren Morris were responsible to question development. Laoise Renwick had oversight of the steering committee, ranking and consensus workshop.The authors have no conflicts of interest to declare.Supporting information.Click here for additional data file.Supporting information.Click here for additional data file.


Comorbidities in sarcoidosis are common, especially cardiovascular and pulmonary diseases.In the diagnostic workup, a distinction must be made between sarcoidosis-related complaints and complaints caused by other separate disorders. It can be very difficult to distinguish between complications of sarcoidosis and other concomitant conditions.The coexistence of multiple conditions may complicate the diagnosis of sarcoidosis, affect its natural course and response to treatment.Sarcoidosis is a heterogeneous disease, which can affect virtually every body organ, even though lungs and intra thoracic lymph nodes are almost universally affected. The presence of noncaseating granulomas is the histopathological hallmark of the disease, and clinical picture depends on the organs affected. Data about interaction between sarcoidosis and comorbidities, such as cardiovascular and pulmonary diseases, autoimmune disorders, malignancy and drug-related adverse events are limited. Several lung conditions can be associated with sarcoidosis, such as pulmonary hypertension and fibrosis, making it difficult sometimes the differentiation between complications and distinctive pathologies. Their coexistence may complicate the diagnosis of sarcoidosis and contribute to the highly variable and unpredictable natural history, particularly if several diseases are recognised. A thorough assessment of specific disorders that can be associated with sarcoidosis should always be carried out, and future studies will need to evaluate sarcoidosis not only as a single disorder, but also in the light of possible concomitant conditions. Sarcoidosis is a heterogeneous disorder affecting several organs and tissues, although the lungs and intrathoracic lymph nodes are the most common localizations of the disease. The histopathological hallmarks are non-necrotising granulomas that may have some distinctive features from other granulomatous disorders, though in some cases they can be indistinguishable . It is gTo this end, a literature search was conducted by searching public databases .Sarcoidosis AND Lungs OR respiratory system OR pulmonary disease;Sarcoidosis AND Heart OR Cardiovascular system OR Cardiovascular risk OR Cardiovascular disease;Sarcoidosis AND autoimmune system OR autoimmunity;Sarcoidosis AND tumours OR neoplastic disease OR lymphoma OR haematologic disorder;Sarcoidosis AND endocrine system OR thyroid disease OR diabetes mellitus OR diabetes OR obesity OR overweight;Sarcoidosis OR Sarcoidosis-like reaction AND drugs OR therapy OR drug treatment OR cortisone therapy OR glucocorticoids OR methotrexate OR azathioprine OR leflunomide OR biological agents OR tumour necrosis factor-alpha inhibitors.Search queries were:Duplicated papers or papers that were not adherent to the topic of the review were excluded.The exact prevalence of sarcoidosis associated pulmonary hypertension (SAPH) remains uncertain due to significant variability in diagnostic methods and criteria used as well as the populations studied. Overall, PH affects 1–6% of sarcoidosis patients , but it th World Symposium, SAPH is placed in Group 5.2 along with other forms of PH deemed to multifactorial and/or unclear pathophysiologic mechanisms  study) had originally reported a prevalence of 5% of cardiac sarcoidosis (CS) . In the The clinical presentation of CS is highly variable as with all forms of sarcoidosis. It can range from an incidentally ECG or echocardiographic abnormality without any symptoms to heart failure and sudden cardiac death depending on the location of granulomatous inflammation. Advanced atrioventricular block  and ventricular tachycardia are the most common ECG abnormalities, while supraventricular arrhythmias may or may not be related with CS. Sudden cardiac death is well reported in the sarcoidosis population even in patients with preserved left ventricular function. In advanced forms of the disease, heart failure develops from extensive myocardial fibrosis and/or inflammation.The diagnosis of CS is often challenging. The lack of a diagnostic gold standard has been highlighted and several diagnostic guidelines have been published to address this issue . EndomyoThe role of CMR is invaluable for the diagnosis and management of CS. CMR is the gold standard tool in providing an accurate assessment of the myocardial structure and morphology as well as tissue characterisation. The detection of late gadolinium enhancement (LGE) on CMR in specific patterns compatible with CS is considered a hallmark of CS. CMR can also detect edoema. T2- weighted sequencing, which is associated with inflammatory activity, has prognostic implications and can be reflective of disease regression during treatment . CMR is FDG-PET scan is useful to detect the presence of active myocardial inflammation, and is usually performed if CMR shows evidence of cardiac involvement or there is a high degree of clinical suspicion of CS . DespiteUnfortunately, there is no optimal strategy developed to screen the sarcoidosis population for cardiac involvement. The American Thoracic Society clinical practice guidelines recommend that all sarcoidosis patients should be interrogated for cardiac symptoms including palpitations, episodes of syncope and pre-syncope as well as  chest pain at every outpatient clinic visit (if possible) and have a 12-lead ECG at baseline . NonetheManagement of CS is focussing on a) eliminating the existing myocardial inflammation, b) supporting the myocardial function when remodelling has occurred and c) preventing future life-threatening arrhythmias. The 10-year survival in CS was recently reported at 90% . Core meThe association between sarcoidosis and autoimmune disorders has been described in several case reports and in large cohorts studies . ConsideA more recent study on a European cohort of 1737 patients found 16% of patients presenting at least one associated immune-mediated disease, with a frequency almost 2-fold higher than in the general population . This suInterestingly, the above mentioned two large cohorts, of similar size but of Eastern and Western origin, strongly agree in indicating that around one out of six sarcoidosis patient may present an associated immune-mediated complication ,95. WhenIt is interesting to note that the authors of the above cited Spanish study used the term “immune-mediated” rather than autoimmune diseases, including in the list the two most common primary antibody deficiencies of the adulthood, namely Common Variable Immunodeficiency (CVID) and selective IgA deficiency. CVID, in particular, was found as the immune-mediated disease with the highest degree of association with sarcoidosis . The defIn conclusion, the occurrence of systemic granulomatous disease in the context of immunodeficiency, autoimmunity and immune dysregulation, chronic infection-driven immune stimulation, as well as after administration of monoclonal antibodies and small molecule inhibitors during the treatment of other autoimmune diseases deserves further mechanistic investigations, highlighting once more the complexity of the pathogenetic pathways underlying sarcoidosis granulomatous inflammation.An association between sarcoidosis and malignancy has been suspected for a long time. Brincker initially hypothesised the importance of this comorbidity in 1972 by observing an association between sarcoidosis cases and lymphomas . The asset al, who followed more than 500 sarcoidosis patients for a long period and similarly did not find a significantly increased incidence of malignant lymphoma  . M. M154]. Second-line agents, such as MTX, an agent originally intended for antineoplastic use, be used as an alternative to GCs ,164,165.To date, in the treatment of sarcoidosis GCs and MTX are the two most commonly used drugs. Currently, the ongoing PREDMETH study - a randomised controlled trial - aims to investigate the effectiveness and tolerability of MTX compared with prednisone as first-line therapy in patients with pulmonary sarcoidosis . The demAzathioprine (AZA) is a purine antagonist that is often used in the management of sarcoidosis when MTX is contra-indicated, such as in pregnancy, or has failed to induce significant improvement. AZA exerts an anti-inflammatory effect by reducing the proliferation of B- and T-cells. Most common ADRs include infections, gastro-intestinal complaints, hepatic function decline and bone marrow depression, but fever and fatigue may also occur. These latter symptoms can be hard to distinguish from sarcoidosis-associated symptoms, but their rapid resolution following drug discontinuation support an AZA-associated phenomenon. AZA is metabolised by thiopurine S-methyltransferase (TPMT), and patients with low TPMT levels can develop severe neutropenia. TPMT genotyping is therefore advised before starting treatment with AZA to reveal patients susceptible to toxicity .Monoclonal antibodies targeting TNF-α, particularly infliximab and adalimumab, are recommended as third-line treatment. Most commonly reported ADRs include infections. Concomitant use of immunosuppressants such as MTX reduces the risk of neutralising antibodies against TNF-α inhibitors and increases drug efficacy . A studyBeside the treatment of sarcoidosis polypharmacy by itself may have a substantial influence. Thus, drug-induced ADRs may cause additional comorbidities in patients with sarcoidosis . Drug-inBesides rare gastrointestinal (GI) manifestations of sarcoidosis (e.g. from the direct involvement of GI system from sarcoidosis lesions), some studies have indeed demonstrated that sarcoidosis is associated with an increased risk events such as upper GI ulcer and/or haemorrhage and diverticulitis. These manifestations, however, are more likely to be side effects of drugs such as NSAIDs and biologic agents. In particular, long-term use of NSAIDs to control chronic symptoms such as musculoskeletal pain, is associated with cyclooxygenase-1 (COX-1) inhibition, reduction of prostaglandins production and increased hazard of gastroduodenal ulcers. The observation that patients using biologic agents have the highest risk of upper GI events supports the hypothesis that dysregulation of the immune system represents a concomitant disease mechanism .In summary, it is important to consider the option of drug-induced damage, especially as the clinical situation deteriorated after the introduction of a certain drug. Patients should be closely monitored for the development of potential ADRs or drug-induced comorbidities. The variability in drug response among patients including sarcoidosis is multifactorial. Therefore, increased recognition and a high index of suspicion are key to proper diagnosis and prompt withdrawal of the offending drug where the mainstay of treatment is drug cessation. Though, early recognising and managing drug-induced morbidity is a real clinical challenge. A tailored approach that can be adopted in clinical practice, based on the disease severity and risk profiles, is warranted. There is a need to develop trials investigating the role of genomic variations in not only disease susceptibility and predicting prognosis, but also treatment response, and in tailoring drug treatment for individual patients. Comorbidities or ADRs of drugs used in the treatment of sarcoidosis are sometimes very hard to differentiate from symptoms of sarcoidosis itself, which may lead to diagnostic issues.The study of the possible interactions between sarcoidosis and other comorbidities is a field of great interest. The coexistence of multiple conditions complicates the diagnosis of the disease and might be responsible, at least in part, for the highly variable natural history of sarcoidosis, particularly if more than one diseases is present. Therefore, a thorough evaluation of all disorders that may coexist with sarcoidosis should be carried out.In particular, assessment organs at high risk of comorbidities, such as heart and lungs, is highly recommended. In turn, functional assessment of these major organs, if involved, should be performed in order to timely initiate appropriate treatment to mitigate disease manifestations and prevent long-term complications. Attention should also be paid to non-specific organ-related symptoms, such as fatigue and pain, which may be caused by adverse drug reactions rather than sarcoidosis. Future studies on sarcoidosis should specifically focus on the presence of comorbidities. In particular, population-based cohort studies should investigate the risk of comorbidities in patients with sarcoidosis, with the aim to predict the long-term risk of comorbidities and related outcomes.


A humidity sensor is a crucial device in daily life; therefore, in the present study, a novel humidity sensor was designed to increase its specific surface area to improve its humid sensing capacity and conductivity. Titanium dioxide nanoparticles (TiNP) consisting of zero-dimensional nanospheres and one-dimensional nanotubes were prepared by anodic oxidation. Rod-shaped cellulose nanocrystals (CNCs) with average length and diameter of 60 nm and 800 nm, respectively, were obtained by enzymatic hydrolysis and high pressure homogenization. TiNP/CNC composite films exhibited superior hydrophilicity and large specific surface areas based on Fourier transform infrared spectroscopy and nitrogen adsorption–desorption results. The humidity sensing characteristics of sensors based on TiNP/CNC flexible composite films with varying contents of TiNP were investigated under a relative humidity range of 11–97%. The 6% TiNP/CNC-based humidity sensor exhibited high humidity response, rapid response/recovery speed, and high stability. Furthermore, the humidity sensing mechanism of TiNP/CNC composite films was analyzed based on the density functional theory. TiNP/CNC-based humidity sensors could be applied in flexible and wearable electronics. Humidity (water vapor) is one of the key meteorological elements that indicate the amount of water vapor in the air and the degree of wetness. Humidity regulation influences many aspects of daily life, such as human health, living environment, and product storage ,2,3. TheIn general, in addition to humidity sensors possessing excellent humidity sensing properties, flexible humidity sensors fabricated with humidity-sensitive materials, interdigital electrode parameters, and flexible substrates, have a unique role in promoting the development of wearable devices . To achiSome researchers have observed that cellulose generally occurs in the form of cellulose fiber, cellulosic paper, or cellulosic film, which when combined with other materials creates a conductive network for humidity sensors . However2) is one of the well-known semiconductor oxides, and has attracted the attention of researchers due to its remarkable properties, including low cost, non-toxicity, and high stability [2 can be a suitable candidate for humidity sensing due to its high responsive conductivity and hydrophilic properties. Notably, the sensing properties of TiO2 materials largely depend on their morphologies, which in turn, are determined by the preparation methods [2 nanomaterials can vary from quantum dots, nanofibers, nanotubes, nanosheets to nanoflowers, and other nanostructures depending on their various synthesis methods, such as hydrothermal synthesis, template-assisted synthesis, and chemical decomposition, among others [2 nanomaterials with relatively large surface areas have numerous porous sites and exhibit better electron transitions, which implies that they may have superior humidity sensing properties.Although CNCs can act as effective scaffold materials for humidity sensing, the choice of humidity-sensitive materials also directly affects sensor performance. To date, a variety of materials, including porous ceramics, semiconducting metal oxides, polymers, metallic nanowires, and carbon-based nanomaterials, have been explored as humidity sensing materials ,15. Titatability . Further methods . The geog others . TiO2 na2 nanoparticles (TiNP) consisting of zero-dimensional (0-D) nanospheres and one-dimensional (1-D) nanotubes were synthesized by anodic oxidation. They can provide several adsorption channels for H2O molecules and facilitate the rapid adsorption and desorption of H2O molecules. The CNCs were obtained by enzymatic hydrolysis combined with high pressure homogenization. The biodegradable CNC materials were used for the preparation of an integrated humidity sensor to enhance the mechanical properties of the composite material and to further improve the sensing properties of the sensor because of the water molecules adsorption capacity of CNCs. Afterwards, material characterizations of TiNP/CNC composite films were performed using a field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and nitrogen (N2) adsorption–desorption analyses. Furthermore, humidity sensing properties of flexible humidity sensors fabricated using TiNP/CNC composite films at room temperature and RH of 11–97% were investigated. Finally, the humidity sensing mechanism of TiNP/CNC composite films was analyzed based on the density functional theory (DFT).In the present study, multidimensional TiO2 nanotube arrays were initially grown via electrochemical anodization of Ti metal foil (0.1 mm) grown in a glycol solution with 0.55 wt% ammonium fluoride and 20 wt% deionized water at 30 V for 6 h. Subsequently, the anodized Ti foil was annealed at 450 °C for 2 h. The calcined nanotube arrays were then broken down and ground manually to obtain TiNP with residual nanotube fragments.Highly ordered and uniform TiOAfter swelling in 50% aqueous propanetriol solution for 2 h, the cotton pulp was pretreated by enzymatic hydrolysis. Based on a total enzyme concentration of 10 U/mL, with cellulase and xylanase combined at a concentration ratio of 9:1, the pretreated pulp was obtained following hydrolysis at 50 °C for 12 h, followed by successive washing and centrifugation cycles. Afterward, final CNC suspensions were sonicated in a high pressure micro jet homogenizer  at 25,000 psi for 15 min.The aqueous CNC obtained was then diluted with ultrapure water to a concentration of 0.1 wt%. Thereafter, CNC dispersions  were blended with TiNP and dispersed using an ultrasonic disruptor  at 50% amplitude for 5 min.Subsequently, the TiNP/CNC composite films with various ratios were prepared by vacuum-assisted filtration using polyvinylidene fluoride membrane filters with pore sizes of 0.22 μm. After filtration, the formed TiNP/CNC gels were pressed to dry in an ambient laboratory atmosphere and then peeled off from the filter membranes. The TiNP/CNC sensors were developed by processing gold interdigitated electrodes on the composite films based on ion sputtering. The synthesis and fabrication processes of TiNP/CNC-based humidity sensors are illustrated in The surface morphology of the TiNP/CNC nanocomposite films was analyzed using a field emission scanning electron microscope , which was equipped with an energy-dispersive spectrometer for characterizing the chemical composition of TiNP/CNC nanocomposite films. XRD patterns were measured using an XRD spectrometer  with Cu Kα radiation operated at 40 kV and 40 mA in the 2θ range of 10°–80°.−1 region, and was performed using a FTIR spectrometer . The N2 adsorption–desorption experiments were performed using an automatic gas adsorption analyzer , with samples being degassed at 60 °C for 12 h to determine TiNP/CNC nanocomposite film porosity and specific surface area. Specific surface area was calculated using the Brunauer–Emmett–Teller (BET) equation and pore size distribution was calculated based on the Barrett–Joyner–Halenda (BJH) method.FTIR spectroscopy was used to identify functional groups in the TiNP/CNC nanocomposite films in the 4000–800 cm2 (33%), KCO3 (43%), MgNO3 (54%), KI (67%), NaCl (75%), KCl (84%), and KNO3 (97%). To achieve optimized sensing performance, six groups of TiNP concentrations  were used to fabricate the sensors, and the electrical signals were measured using a gas sensing measurement system .The characteristics of TiNP/CNC-based humidity sensors under various humidity conditions were determined by placing them in series of closed bottles with saturated solutions of different salts at room temperature. The various humidity conditions created by saturated solutions of different salts were as follows: LiCl (11%), MgCl0 is the initial resistance of the sensor at 11% RH and R is the final resistance at testing RH level.The response of the TiNP/CNC-based humidity sensor was calculated using Equation (1) as follows:2O) molecules on TiO2 surface, a representative (101) surface of anatase TiO2 thin film was considered [2 (101) surface was modeled by a periodic (2 × 2) slab with two O–Ti–O layers.To explore the adsorption behavior of water  surface has two types of atoms: the topmost atoms are five-fold coordinated Ti atoms  and two-fold coordinated O atoms (O2c), which have the highest probability of reacting with gases [6c) and three-fold coordinated O atoms (O3c).The anatase TiOth gases . The oth23p63d24s2, O 2s22p4, and H 1s, respectively. To calculate the adsorption energy, Eads of H2O molecules on anatase TiO2 (101) surface, the following expression was used:2O) surface, while E(slab) and E2O), (103), (004), (112), (200), (105), (211), and (204) crystal planes of anatase phase of TiO2, respectively (JCPDS-21-1272) [2 and CNCs were not altered after forming a composite.XRD was used to test the crystal structure of the 6% TiNP/CNC composite films. XRD spectra of TiNP/CNC composite films are illustrated in 21-1272) . Moreove21-1272) . Therefo−1 are ascribed to the -OH group absorption peaks, whereas those observed at 2894 cm−1 resulted from C–H stretching in methylene groups [−1. The broad absorption band observed in the 3100–3600 cm−1 region can be attributed to the stretching mode of the -OH group. The -OH group is hydrophilic, and can indicate the capacity of a sample to adsorb H2O molecules [The FTIR spectrum of 6% TiNP/CNC composite film is illustrated in e groups . The chaolecules .2 adsorption–desorption experiments were performed. The N2 adsorption–desorption isotherms and pore size distributions of pure CNC and of 6% TiO2/CNC composite films are illustrated in 2/g and 12.39 m2/g, respectively. The values indicated that the CNC films had considerably low porosity due to CNC aggregation. In contrast, 6% TiNP/CNC composite film exhibited relatively high surface areas, suggesting that TiO2 nanocrystals considerably hindered the stacking of CNC particles. The porous structure of TiO2 nanotubes also increases the specific surface area of the composite films. The 6% TiNP/CNC composite film exhibited type IV nitrogen adsorption isotherms when compared to pure CNCs , short response and recovery times, and high repeatability . TherefoThe humidity sensing capacity of TiNP/CNC composite films was investigated based on a RH range of 11–97%, which was achieved by using various saturated salt solutions at room temperature.2O molecules coming into contact with the composite film structure; in turn, response of the sensors decreases considerably. The highest TiNP/CNC-based humidity sensor response was observed when TiNP content was 6%.The dynamic response curve of the 6% TiNP/CNC-based humidity sensor under 11–97% RH conditions is illustrated in 2O molecules, which are one of the key indicators of the practical application value of a sensor.The response and recovery times for the 6% TiNP/CNC-based humidity sensors to 43% RH are 34 s and 18 s, respectively, as illustrated in 2. It can be seen in 2O molecules through hydrogen bonding; the interwoven network of CNC and multidimensional structure of TiNP gives more channels for H2O molecules.Repeatability and long-term stability are also key parameters of humidity sensors for practical sensing applications. The responses of the 6% TiNP/CNC-based humidity sensors are evaluated in five sensing cycles at 33%, 54%, and 75% RH a. The re2O molecules easily adsorbed on the TiO2/CNC composite film, and the interwoven network and TiNP structure give more channels for H2O molecules. To elucidate the humidity sensing mechanism of TiO2/CNC-based humidity sensors, the interaction between H2O molecules and anatase TiO2 (101) surface was investigated. The optimized geometries of H2O molecules adsorbed on anatase TiO2 (101) surfaces with four adsorption sites are illustrated in CNC is rich in hydroxyl groups, which makes H2O adsorption and surface relaxation, except those at the Ti6c site. The adsorption structure diagram of Ti6c revealed that one of the H atoms split from H2O and diffused to the adjacent bridging oxygen surface, indicating the formation of an O–H bond at the surface [ads), adsorption length (Da) (defined as the length between the gas molecules and the nearest atom on anatase TiO2 (101) surface), bond length (RO-H1 and RO-H2), bond angle (∠H–O–H), and band gap (Eg) are summarized in The atomic structures were almost identical after H surface . The ads2O molecules on the Ti5c site of TiO2 surface was −0.693 eV, which is consistent with the experimental results (−0.72 eV) of previous studies [2O and anatase TiO2 (101) surfaces were characterized by negative Eads values, which suggests that the exothermic process does not require additional energy, with the system becoming more stable after adsorption. Moreover, the adsorption energy value of H2O on the Ti5c site was higher than those on other sites. The adsorption energy of the O3c site was similar (−0.690 eV) to that of the Ti5c site; however, the adsorption bond length of the O3c site (2.896 Å) was significantly longer than that of the Ti5c site (2.313 Å). Shorter bond lengths observed between H2O molecules and anatase TiO2 (101) surfaces imply that there were stronger interactions between H2O molecules and TiO2 surface, and therefore a more stable adsorption conformation. Furthermore, when H2O adsorption at the Ti6c site causes a relatively large relaxation of the TiO2 structure, the Ti–O bond between the O atom below the TiO2 surface and the subsurface Ti atom is broken and the O atom position significantly shifts upward . The band gap of TiO2 decreased to 2.491 eV when H2O molecules were adsorbed on the Ti5c site.The calculated band gap values of TiOe system . The ban2O molecules on the Ti5c site of anatase TiO2 (101) surface at the initial stage. To further reveal the effect of each subsystem on molecular orbital density, projected density of states (PDOS) of TiO2 surface after adsorption of H2O molecules are shown in Therefore, response of the TiNP/CNC-based humidity sensor is stimulated by the chemical adsorption of H2O adsorption. New energy levels are formed in the energy band structure of TiO2 when H2O molecules are adsorbed. The chemisorption process of H2O molecules results in the formation of an adsorption complex ) [ complex b. The adion (3)) ,37.2H2O2O molecule is adsorbed through hydrogen bonding between two neighboring OH groups. The condensed topmost H2O molecules cannot move freely due to restrictions associated with the two hydrogen bonds [3O+) in the H2O layer becomes a challenge, which leads to low conductivity [Subsequently, another Hen bonds . During uctivity . The TiN2O molecules are ionized under an electrostatic field, in turn, generating numerous H3O+ as charge carriers with an increase in humidity levels (Equation (4)) [During the following stage, Hion (4)) .H3O+→H22O molecules on the physisorbed layer, which behaves like a normal liquid. Therefore, the hopping of protons through adjacent H3O+ increases conductivity [2O molecules with OH groups to form a physisorbed layer, where carriers can be transferred easily, in turn, decreasing resistance [2O molecules, which accelerates response speed [Afterwards, increasing humidity levels lead to adsorption of more Huctivity . A furthsistance . In addise speed . Therefo-) on CNC surface, more H2O molecules can be adsorbed on the surface. After the multi-level nanostructured TiO2 is compounded with CNC, spherical TiO2 particles form a porous structure with adjacent CNCs, which has good adsorption capacity and facilitates the formation of a continuous H2O layer, in addition to serving as a direct conduction pathway for the improvement of the sensing membrane conductivity. Tubular TiO2 also provides several adsorption channels for H2O molecules, which is conducive to the rapid adsorption and desorption of H2O molecules. Therefore, TiNP/CNC composite nanostructures enhance humidity sensing properties.Notably, due to the presence of certain hydrophilic functional groups  and 1-D residual nanotubes (average pore diameter of 200 nm) of TiO2O molecules. The band gap, adsorption energy, and PDOS of optimized TiO2 were calculated before and after adsorption of H2O molecules.The humidity sensing characteristics of the TiNP/CNC-based humidity sensors with various TiNP contents (1–12 wt%) were analyzed. The results revealed that the 6% TiNP/CNC-based humidity sensor exhibited remarkable sensing characteristics, including high response in a wide RH detection range (11–97% RH), rapid response and recovery time, as well as high reproducibility and stability. This highlights the advantages of using TiNP/CNC composite films in the fabrication of high quality humidity sensors at room temperature. Furthermore, DFT calculations were performed to determine the sensing mechanism of TiNP/CNC composite films based on interaction with H2O layer and act as a direct conduction pathway for the enhancement of humidity sensing performance of the flexible TiNP/CNC composite films. In addition, TiNP/CNC-based humidity sensors confer the following advantages: flexibility for application in wearable devices, non-toxic for human use, low cost, and simple manufacturing technology, in addition to degradability and non-polluting properties. Therefore, flexible humidity sensors fabricated from TiNP/CNC composite films could be a potential strategy for developing multifunctional humidity sensors due to their high response and wide RH detection range capacities.The nanostructure of the TiNP/CNC composite films enhanced the humidity sensing properties of the sensors. The interlaced CNC and multidimensional TiNP structures have superior adsorption properties, which facilitate the formation of a continuous H


In this paper, the refined plate theory (RPT), Hamilton’s principle, and isogeometric analysis (IGA) are applied to investigate the static bending, free vibration and buckling behaviors of functionally graded graphene-platelet-reinforced piezoelectric (FG-GRP) plates resting on a Winkler elastic foundation. The graphene platelets (GPLs) are distributed in polyvinylidene fluoride (PVDF) as a power function along the plate thickness direction to generate functionally gradient materials (FGMs). The modified Halpin–Tsai parallel model predicts the effective Young’s modulus of each graphene-reinforced piezoelectric composite plate layer, and the rule of the mixture can be used to calculate the effective Poisson’s ratio, mass density, and piezoelectric properties. Under different graphene distribution patterns and boundary conditions, the effects of a plate’s geometric dimensions, GPLs’ physical properties, GPLs’ geometric properties and the elastic coefficient of the Winkler elastic foundation on deflections, frequencies and bucking loads of the FG-GRP plates are investigated in depth. The convergence and computational efficiency of the present IGA are confirmed versus other studies. Furthermore, the results illustrate that a small amount of GPL reinforcements can improve the FG-GRP plates’ mechanical properties, i.e., GPLs can improve the system’s vibration and stability characteristics. The more GPL reinforcements spread into the surface layers, the more effective it is at enhancing the system’s stiffness. Functionally gradient materials (FGMs), first developed in 1987, are composite materials with two or more distinct phases. FGMs provide designers with a range of options to distribute strength and stiffness in an appropriate manner ,3,4. NovOn the other hand, piezoelectric ceramic, one kind of smart material, has excellent electro-mechanical coupling behaviors. Piezoelectric sensors can convert mechanical energy to electrical energy, making them beneficial in civil engineering, automotive and aerospace . With th1-continuity of the displacement fields, which presents challenges to the traditional finite element analysis (FEA) framework [1-continuity of displacement fields required by RPT. In recent years, researchers have frequently used IGA to analytically calculate the mechanical properties of functionally graded composites. On the basis of IGA and TSDT, Kiani et al. [Many scholars have proposed theoretical models that combine shear deformation theory  with varramework . Furtherramework  originalramework ,44, T-spi et al. ,46 invesi et al.  utilizedi et al.  combinedi et al.  investigTo the best of the authors’ knowledge, no literature is available for the analysis of functionally graded graphene-platelet-reinforced piezoelectric structures based on isogeometric analysis. As a result, the purpose of this work is to investigate the static bending, free vibration and buckling behaviors of functionally graded graphene-platelet-reinforced piezoelectric plates embedded on a Winkler elastic foundation using isogeometric analysis and refined plate theory. The object of this paper is to development isogeometric analysis of graphene-reinforced functionally gradient piezoelectric plates resting on Winkler elastic foundations. This paper is organized as follows. In a, width b, and thickness h on Winkler elastic foundation is established. The FG-GRP plate is supposed to be made of a multi-layer polymer composite reinforced by graphene platelets, where the GPL reinforcements are functionally graded along the thickness direction with a power law distribution. Furthermore, the thickness of each independent layer may be described as As illustrated in In this research, three graphene distribution patterns are generated by smoothly varying the graphene volume fractions along the thickness direction, as shown in The total graphene volume fraction is expressed as k-th layer of the FG-GRP plate can be written as follows:The volume fraction in the The U type:The X type:The O type:k-th layer asG and M symbolize graphene platelet and matrix material, and As demonstrated by Layek et al. , GPL reik-th layer may be predicted byFurthermore, the effective material properties, such as Poisson’s ratio, density, piezoelectric constant, and dielectric constant for the The displacement fields The in-plane strain and transverse shear strains corresponding to the displacement fields are shown ask-th layer constitutive relationship is represented asAccording to the generalized Hooke’s law, the For the FG-GRP plate, the constitutive equation is expressed asAccording to Equations (9)–(13), the FG-GRP plate’s mid-plane internal force The internal force The Galerkin weak form of the governing equations is calculated using the Hamilton principle .(18)δ∫tn and p denote the ith knot, the number of basic functions, and the polynomial order, respectively.The main elements of the B-spline curve are a set of control points According to the Cox–de Boor recursive formula , the B-sIt should be noted that the ratio 0/0 in the preceding Equation (20) is given as zero.The B-spline basis function is mostly made up of specified spline basis function orders and related knot vectors, and its expression is expressed as follows:The B-spline function can be a particular case of the NURBS function when weights of control points are constant. The bi-variate NURBS basis functions are written asThe NURBS spline surfaces are defined by supplying knot vectors and control points in two parameter directions, and the derivative of IP.By adopting the NURBS basis functions, the approximate mechanical displacement field Taking Equation (25) into Equation (9) yieldsith sublayer,After approximating the potential field, the system can be discretized into several sublayer elements along the thickness direction . The appHere, assuming that each individual piezoelectric layer has the same potential at the same height, we may obtain the electric field of each sublayer unit by substituting Equation (28) into Equation (13).U is the applied voltage to the upper and lower surfaces.The governing equation of motion of the FG-GRP plate can be found by inserting Equations (12), (26) and (30) into Equation (18):The element stiffness matrix for buckling analysis can be represented as:The edges of the FG-GRP plate are subjected to a uniaxial load and biaxial loads, as shown in To evaluate the impact of the Winkler elastic foundation, the additional matrix Eliminating the potential and assembling elements, the governing equations of FG-GRP are represented as:The governing equations for static analysis, free vibration and buckling behaviors are obtained as followsIn this section, static analysis, free vibration and buckling behaviors of FG-GRP plates on Winkler elastic foundation are investigated by isogeometric analysis. Unless otherwise specified, an FG-GRP plate with geometric size multiple . Furthermultiple  are:EgplThe following dimensionless formula is used in this paper unless otherwise specified:Firstly, the convergence of the IGA technique is examined by adopting Firstly, the FG-GRP plates are modelled with 7 × 7, 11 × 11 and 19 × 19 control points as shown in o et al. . It can N, more GPL reinforcements are spread on both sides of the plate to enhance the stiffness of the system. While for the other one, the O type plays opposite roles on the stiffness and dimensionless central deflections. Simultaneously, with increasing the number of layers N, the percentage deflection changes corresponding to the X and O types gradually converge when The effective material properties for the composite are determined by the length and thickness of the graphene reinforcements but have nothing to do with the width in Halpin Tsai’s parallel model . AssuminThe impact of the Winkler elastic coefficients In what follows, the influence of detailed parameters on free vibration analysis for an FG-GRP plate with As shown in The effect of the Winkler elastic coefficient on the dimensionless vibration frequencies of the FG-GRP plate is shown in To explore the impact of detailed parameters on the buckling behaviors, the uniaxial or biaxial in-plane forces must be applied to the piezoelectric plates.x and y directions is loaded from four directions, limiting the load it can carry. Next, the normalized critical buckling load The impact of the length-to-width ratio Isogeometric analysis integrated with the refined plate theory is utilized in this paper to analyze the static bending, free vibration and buckling behaviors of functionally graded graphene-platelet-reinforced piezoelectric plates on Winkler elastic foundations. When Hamilton’s principle is combined with isogeometric analysis, the isogeometric finite element governing equations of the functionally graded graphene-platelet-reinforced piezoelectric plate are obtained on the basis of the refined plate theory. Comparisons with other studies validate the accuracy and convergence of the present isogeometric analysis. Furthermore, the influences of a plate’s geometrical parameters, the elastic coefficient, and GPLs’ physical and geometric properties on the percentage change of central deflections, frequencies and critical buckling loads of a functionally graded graphene-platelet-reinforced piezoelectric plate are thoroughly investigated under different boundary conditions and graphene distribution patterns.The results of this paper indicate that adding a small amount of GPL not only decreases the central deflections, but also increases the vibration frequencies and critical buckling loads of functionally graded graphene-platelet-reinforced piezoelectric plates. Additionally, the X type represents the optimum distribution form, i.e., the higher the graphene volume fractions spread into the surface layer, the more effective it is to enhance the stiffness of the system. Additionally, increasing the graphene length-to-thickness ratio can significantly enhance system stiffness, that is, the longer and thinner the GPLs are, the more obvious the reinforcement is. In terms of a plate’s geometrical parameters, the effect of a functionally graded graphene-platelet-reinforced piezoelectric plate’s aspect ratio on central deflections, vibration frequencies and critical buckling loads should be handled differently depending on the graphene distribution pattern. For the X type, increasing the aspect ratio or plate surface area can improve system stiffness. In terms of the impacts of boundary conditions on the system, the stiffness of the functionally graded graphene-platelet-reinforced piezoelectric plate under the CCCC boundary condition is the highest one, followed by CCSS, CSSS, and SSSS. Furthermore, the dimensionless critical buckling load subjected to the uniaxial force is approximately twice as large as that subjected to the biaxial force. Effectively increasing the elastic coefficient of the Winkler elastic foundation can obtain a remarkable reinforcement effect on the plate stiffness.


Idiopathic pulmonary fibrosis (IPF) is the “mother” of all idiopathic fibrotic interstitial lung diseases (ILDs), the most common and clinically severe, and although it invariably presents an ominous prognosis, its clinical course is highly unpredictable, lasting at diagnosis from months to almost a decade . Acute dAlthough Hamman and Rich are considered the first to describe, in the early thirties, the new diffuse interstitial fibrotic lung clinical entity, presumably IPF , its fir2/FiO2 ≤ 300, presenting with “influenza-like symptoms and/or cough and fever; leukocytosis and high CRP; with biopsy proven, at least in two of them; and UIP histology and acute lung injury (ALI)” (The modern history of IPF-AEs begins probably in 1993 when Yashuhiro Kondoh reported a case series of three patients with IPF fulfilling ARDS criteria including PaOy (ALI)” . The “aby (ALI)” . Since ay (ALI)” .Thirteen years later, in an international expert’s report on IPF, the idiopathic nature of IPF-AEs constitutes the first hypothesis on their etiology, though the dilemma “do acute exacerbations of IPF represent a distinct pathobiological manifestation of the primary disease process or are they caused by occult complications such as infection and aspiration” dominates the key questions remaining for future research . In the However, the aforementioned considerations regarding theory and practice of IPF-AEs were not universally adopted, and our group of investigators in a review article based on own clinical observation sustained that in the clinical context of a rapidly deteriorating IPF patient, clinicians are faced with three different scenarios: first, the progression toward the “final end” of the disease where spontaneous breathing becomes unsupportable because of the excessive fibrotic lung derangement and where palliation of breathlessness appears the only option; second, the development of a new clinical complication , reversible when promptly diagnosed and appropriately treated; and third, the true development of ARDS upon IPF . In thisN-acetylcysteine versus placebo “was associated with increased all-cause mortality, all-cause hospitalizations, and treatment-related severe adverse events; deaths and hospitalizations happened early in the combination-therapy group,” and finally, AEs developed only in the treatment arm of the study  in both arms . However, clinicians and researchers seem persuaded for the need of a new randomized controlled trial to address the efficacy and safety of steroids alone in IPF-AEs in the future   .Several considerations including ethical ones may arise in the designing of new studies on steroids: an arm of the placebo without antimicrobials may not be ethical and using antimicrobials in both arms is against testing the hypothesis of the idiopathic nature of IPF-AEs; but do we really need new trials? Both the PANTER and EXAFIP trials are consistent regarding their results: the PANTHER trial demonstrated that in stable IPF, the combination of steroids and immunosuppressants is associated with increased mortality and induces AEs , and theIn conclusion, for some, controversy still surrounds the treatment of IPF-AEs, but not for all . “Well a


In addition, this pressure sensor has excellent durability (>2000 cycles) and shorter response times (490 ms), which has broad research prospects in human health detection and motion detection.With the improvement of science and technology, flexible sensors have become a hot research topic. Flexible sensors have broad application in human health detection and motion detection and other fields. In this paper, the silk fibroin/graphene nanofiber membranes were prepared by double needle electrospinning. In addition, the high sensitivity of the three-dimensional composite hierarchy was obtained by superimposing a monolayer silk fibroin/graphene nanofiber membrane, which was prepared via double needle electrospinning. In addition, the three-dimensional hierarchy was encapsulated by polydimethylsiloxane to prepare a pressure sensor. The sensitivity of the pressure sensor can achieve 7.7 Pa The sensor is very crucial as a man–machine interaction interface . The phy−1) and a wide operating range (0–20 kPa). The strain sensor showed excellent sensitivity (strain coefficients 22.6–83.7) and 27% large working strain.Graphene (Gr), a two-dimensional carbon material which consists of a single layer of SP  carbon aSilk is a natural protein fiber, which possesses unique combined merits such as programmable biodegradability, good biocompatibility, and large-scale sustainable production. Compared with other biocompatible and biodegradable biomaterials, such as polycaprolactone (PCL), polylactic acid (PLA), poly(lactic-co-glycolic acid) (PLGA), etc., silk is a natural protein and is easy to obtain at a low cost. However, for natural biomaterials, silk has good regenerative properties and can be processed into various forms of materials . Thus, sElectrospinning is a common technique for preparing nano-sized fibers. Electrospinning is possibly not as new as forcespinning (FS) or the centrifugal spinning method for the fabrication of nanofibers. However, the electrospinning technology is more mature and reliable. Furthermore, the prepared nanofibers are more uniform. In addition, the fiber orientation is adjustable . Thus, i3CH2OH  was obtained from Chuandong Chemical Co. Ltd., Chongqing, China. Polyvinylpyrrolidone  was obtained from Aladdin Chemical Co. Ltd., Shanghai, China.Silk fibroin extracted from silkworm cocoons provided by the Southwest University. 1,1,1,3,3,3-Hexafluoro-2-propanol  was obtained from Aladdin Chemical Co. Ltd., Shanghai, China. Graphene , was obtained from Aochuang technology Co. Ltd., Shenzhen, China. CH2CO3 (0.05 wt%) for 30 min each time. Then, they were washed with deionized water to remove the sericin before drying. Silk fibroin fibers were dissolved in CaCl2/EtOH/H2O solution . After 5 days of dialysis, the SF solution was centrifuged at 8000 r/min for 10 min. Then, the desired SF solids were obtained by freeze-drying SF solution at −40 °C. The preparation process is shown in The cocoons were cut into pieces and boiled twice in NaThe weight of 3.2 g silk fibroin was dissolved in 20 mL of HFIP. Electrospinning solution A was obtained. The optimal dispersion ratio of graphene and PVP is 1:3 (As shown in Twenty milliliters of solution A (SF/HFIP) and 20 mL of solution B (Gr/PVP/ethanol) were put into two syringes for electrospinning at the same time. The distance between the syringe needle and the roller was 15 cm, and the syringe was propelled at a speed of 2.0 mL/h. Voltage parameters have positive voltage of 20 KV and negative voltage of 2 KV, respectively. The preparation process is shown in The production process of SF/Gr sensor was divided into three steps. The first step was to extract silk fibroin from a silkworm cocoon. Then, electrospinning solution was prepared. Graphene was poured into anhydrous ethanol. The PVP was added as a dispersant and sonication for 2 h to make graphene disperse evenly in anhydrous ethanol. Secondly, SF/Gr nanofiber membrane was prepared by electrostatic spinning. Finally, SF/Gr nanofiber membrane was encapsulated by PDMS to obtain an SF/Gr flexible pressure sensor.The surface morphology of SF/Gr nanofiber membranes was analyzed by SEM . The porosity and diameter distribution of nanofibers were analyzed using the software ImageJ  by SEM images. In addition, the water contact angle of nanofiber membranes was characterized by an Optical Contact Angle Tester . The thermostability was performed on TG 209F3 Thermogravimetric Analyzer from NETZSCH , amide II (1600–1500 cm−1), and amide III (1350–1200 cm−1), respectively. As can be seen from −1, 1517 cm−1, and 1240 cm−1. There are three characteristic peaks of PVP, which should appear in the vicinity of 1290 cm−1, 1660 cm−1 and 1463 cm−1, respectively. They are attributed to the stretching vibration of CN, C=O, and CH2 bond, respectively. As can be seen from −1. The other two characteristic peaks may not appear because silk fibroin protein has the same groups in the same position. This may lead to the fusion of the peaks. It can be seen that the addition of graphene and PVP has almost no effect on the structure of silk fibroin. Graphene has almost no activity in the infrared spectrum. It can be judged that PVP and graphene are physically bound to silk fiber.Four membranes were tested by the infrared spectrometer . Silk fiThe mechanical properties of the four nanofiber membranes are shown in S) is calculated as S = (Δ0I/I)/ΔP. I0 is the initial current of the sensor under no pressure. ΔI is the relative change of current when the sensor is subjected to pressure. ΔP is applied pressure. As shown in −1. Therefore, the SF/Gr sensor named Gr10 mg-3 was selected for follow-up research.The sensing performance of pressure sensors can be evaluated by response time, sensitivity, stability, etc. The sensitivity test system consists of two parts. The first part is the pressure applying system, which is supplied by a universal stretcher machine. The second part is an electrical signal monitoring system, which consists of an electrochemistry workstation and computer. When the SF/Gr sensor is subjected to pressure, the transmitted electrical signal changes with the change of resistance due to the deformation of the three-dimensional network structure inside the sensor. The sensitivity  of the sensor circuit consists of the volume resistance (vR) of the graphene sheet, the resistance of silk fiber and PVP fiber (GPR), and the contact resistance between the graphene sheets (CR). Copper foil is a conductive metal, and its resistance can be ignored. The calculation formula is as follows:The SF/Gr pressure sensor model is shown in the figure below. The total resistance . Therefore, it can be approximated that the change of the total resistance is caused by contact resistance of graphene. The sensor circuit can be modeled (S = (I − I0/I0)/ΔP. With the increase of graphene concentration, the graphene sheets dispersed more densely in the fiber network and the more graphene was contacted under pressure. In addition, the resistance value was decreased. The I was increased, while I0 was close to 0. Therefore, the sensitivity showed an increasing trend. The sensitivity variation trend of Gr10 mg-1, Gr15 mg-1, and Gr20 mg-1 could prove this conclusion  composite membranes were prepared by electrospinning. The morphology, porosity, water contact angle, and diameter distribution of SF/Gr nanofiber membranes were characterized. The results suggested that SF/Gr nanofiber membranes possess good mechanical properties to make into 3D flexible sensors. Thus, the graphene/silk fibroin nanofiber membrane was packaged by PDMS into a pressure sensor. The prepared SF/Gr pressure sensor has a sensitivity of 7.7 Pa


Polypropylene (PP), as a general thermoplastic polymer, is broadly used in different fields. However, the high flammability, melt dripping and poor mechanical properties of PP are a constraint to the expansion of its applications. In this paper, PP composites containing a combination of a phenethyl-bridged DOPO derivative (PN-DOPO) and organic montmorillonite (OMMT) were prepared via melt blending. The synergistic effects of PN-DOPO and OMMT on the flame retardancy, thermal stability and mechanical properties of PP composites were investigated systematically. The results showed that 20 wt% addition of PN-DOPO with OMMT improved the flame retardancy of PP composites. In particular, the introduction of 17 wt% PN-DOPO and 3 wt% OMMT increased the LOI values of the PP matrix from 17.2% to 23.6%, and the sample reached the V-0 level and reduced the heat release rate and total heat release. TGA indicated that OMMT could improve the thermal stability of the PP/PN-DOPO blends and promote the char residues of PP systems. Rheological behaviour showed a higher storage modulus, loss modulus and complex viscosity of PP/PN-DOPO/OMMT composites, suggesting a more effective network structure. In addition, the tensile strength, flexural properties and impact strength of the PP/PN-DOPO/OMMT composites actually increased for a good dispersion effect. Combined with the char layer analysis, the introduction of OMMT promoted more continuous and compact structural layers containing an aluminium–silicon barrier and phosphorus-containing carbonaceous char in the condensed phase. OMMT can improve the flame retardancy, thermal stability and mechanical properties of PP, and, thus, PN-DOPO/OMMT blends can serve as an efficient synergistic system for flame-retarded PP composites. Polypropylene (PP), a general thermoplastic, is used in automotives, buildings, transportation and electronic devices owing to its excellent electrical insulation properties, corrosion resistance, comprehensive mechanical properties and easy processability ,2,3. HowIn order to improve the fire resistance of the PP matrix, phosphorus-, silicon- or nitrogen-based flame retardants are usually added into the matrix. The intumescent flame retardants (IFR) composed of charring agents, a gas source and acid sources have attracted interest because of their anti-dripping, low toxicity, low smoke and eco-friendly characteristics ,7. NeverAmong the commercial halogen-free FRs, phosphorus-based compounds possess unique advantages, such as a high chemical resistance, the nonproduction of toxicants and no transfer. Recently, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and its derivatives have attracted much attention because of their excellent flame-retardant efficiency, high reaction activity and low addition ,15. DOPOOMMT can form a barrier on the surface of a polymer during combustion and can improve the physical and mechanical properties of the polymer matrix at low concentrations. Furthermore, the thermal stability of flame-retarded composites increases with the increasing OMMT amount ,27,28. WBased on our previous reports, a novel phenethyl-bridged DOPO derivative (PN-DOPO) was prepared. The effects of PN-DOPO on the flame-retardant and thermal properties of the polymeric matrix, such as polyamide, epoxy resins and polylactide, were examined ,33,34,35In this study, PP/PN-DOPO/OMMT composites were prepared through melt mixing. The synergistic flame-retarded effect, thermal stability and rheological behaviour of PN-DOPO combined with OMMT on PP was evaluated. The composition structure and morphology of char residues were investigated systematically. Furthermore, the possible synergistic effect of PN-DOPO and OMMT on the flammability and mechanical properties of flame-retarded PP were also discussed.Polypropylene resin (F401) was purchased from Yangzi Petroleum Chemical Company  with a melt flow index of 2.5 g/min . The FR, phenethyl-bridged DOPO derivatives  at 190 °C with a screw speed of 50 rpm for 6 min. The UL-94 vertical combustion test was performed according to ASTM D3801 with a sample size of 130.0 × 13.0 × 3.2 mm. The LOI values were obtained using the LOI instrument according to ASTM D2863-06. The sample dimensions were 130.0 × 6.5 × 3.2 mm. Microscale combustion calorimeter (MCC) tests were conducted using an MCC-2 instrument . The powder samples (approximately 5–7 mg) were heated from 40 °C to 650 °C at a heating rate of 1 °C/s in an aluminium crucible. The heating atmosphere is a mixture of nitrogen flowing at 80 mL/min and oxygen flowing at 20 mL/min.The thermal stability of the samples was analysed via thermogravimetric analysis (TGA)  under nitrogen atmosphere at a flow rate of 60 mL/min. Each sample (approximately 6–10 mg) was heated from 30 °C to 700 °C at 10 °C/min heating rate.The morphology of the char residues after UL-94 tests was obtained via SEM  at an acceleration voltage of 10 kV.Energy dispersive spectrometry (EDS)  was performed to characterise the chemical composition of the residues. EDS analyses were recorded on SEM equipped with an EDS accessory under high vacuum conditions at a voltage of 30 kV.−8 mbar. The C, O, P, Si and Al on the char residue of the samples were investigated.X-ray photoelectron spectroscopy (XPS)  was performed using an Al Kα source at a base pressure of 1.0 × 10The rheological behaviour of samples was analysed using a Rheometric Analyzer  using parallel plates with diameters of 35 mm. Dynamic frequency sweep tests were measured at 190 °C using 1% strain in an angular frequency range of 0.1–100 rad/s.The mechanical properties of flame-retarded PP composites were measured using a CMT6104 universal testing machine . The tensile tests were measured according to ASTM D-638 using an extensometer. The flexural tests were performed according to ASTM D-790. For each sample, the results were an average of five specimens, and the range of standard deviations was within 5%. A notched Izod impact test was experimented using a pendulum impact tester  according to ASTM D-256.1 and t2 in the UL-94 test decreased gradually with increasing PN-DOPO content. Dripping was no longer observed when the PN-DOPO content was 15 wt%, and a UL-94 V-1 rating was attained. For PP/20 wt% PN-DOPO, the LOI value increased to 23.1% and attained a UL-94 test V-0 rating. The improvement in the flame retardancy of PP/PN-DOPO composites was apparent in the UL94 and LOI flammability test. This behaviour is mainly attributable to the principal gas phase activity of the DOPO derivatives [The UL-94 test and LOI measurement are widely used to evaluate the flame retardancy of polymers. ivatives .OMMT was incorporated into the PP/PN-DOPO composites to improve the flame-retardancy efficiency further and decrease the need for high loadings (20 wt%). The loading of PN-DOPO/PMMT compounds was maintained at 20 wt% in the PP samples. When 1 wt% and 3 wt% OMMT replaced the same content of PN-DOPO, respectively, the V-0 rating was reached, and the variation in LOI values was not evident. With increases in the OMMT amount, the UL-94 rating of V-1 was achieved for both PP-7 and PP-8. Moreover, the LOI values were slightly increased to 24.0% and 23.8%, respectively, which were higher than that of PP-3. However, for only 7 wt% OMMT content, the LOI value of PP-9 was 20.3%, and no rating was reached.As shown in pHRR), could be obtained from MCC tests [The MCC test is an effective method to investigate the combustion properties of polymers. The combustion behaviour of PP composites was analysed using MCC tests. Some important parameters, such as the specific HRR, total heat release (THR) and temperature of peak HRR  originated mainly from the P–O and P=O bonds. From the spectrum of PP/7%OMMT, the C1s spectra featured two bands with binding energies of 284.6 and 285.7 eV. For O1s spectra, the 532.3 eV peak can be attributed to the –O– bond. The 533.6 eV binding energy was ascribed to the C=O groups in carbonyl compounds. A single peak at 102.8 eV in the Si2p spectrum was assigned to the Si–O bond in clay platelets. The Si–O–Si structure generally acts as an enhanced framework for char formation and provides a synergistic effect on flame-retarded composites [XPS can be used to examine the chemical structure of char residues. The composition of residues was also characterised by XPS. ectively ,50. The mposites .1s spectra have three bands with binding energies of 284.7, 285.7 and 288.1 eV. The 284.7 and 285.7 eV peaks were assigned to the C–H or C–C groups and C–O group, respectively. Furthermore, the binding energies of 288.1 eV can be attributed to the C=O or carbonyl groups [From the spectrum of PP/17%PN-DOPO/3%OMMT, the Cl groups . Hence, Overall, XPS confirmed that the hybrid of phosphorus-, silicon- and aluminium-containing compounds could promote a more continuous and compact char layer. The char layer can effectively decelerate the mass and heat transfer between the solid and gas phases. In this case, the PP/PN-DOPO/OMMT composite exhibited a synergistic flame-retardant effect on char formation.The influence of the melt flow characteristics on the combustion behaviour of flame-retarded composites’ nanoclay-containing and phosphorus-containing FRs was investigated ,52. The Similar trends are observed in the complex viscosity of PP and flame-retarded PP composites . The visBased on the above results, the possible synergistic flame-retardant effect between OMMT and PN-DOPO can be discussed as follows. For pure PP, it burnt out without leaving any char residue, accompanied with vigorous dripping during combustion. For PP/PN-DOPO blends, the char residue of the sample with broken holes and many voids in the cavity structure was observed owing to gas phase quenching at the initial stage of combustion ,31. WithThe mechanical properties were investigated to evaluate the effects of OMMT/PN-DOPO compounds on PP. The mechanical properties of composites depend on the compatibility of the fillers within the matrix. This OMMT layer and flame retardant played a reinforcing role in PP composites. Additionally, the tensile strength and flexural property of composites were improved  with theIn conclusion, when OMMT and PN-DOPO were applied to flame-retarded PP, the composites imparted a presented significant synergistic flame-retardant effect on the combustion behaviour, melt viscosity, thermal stability and char formation. In addition, they also enhanced the mechanical properties, such as tensile strength, flexural properties and impact strength, compared with the PP/PN-DOPO system.Different ratios of PN-DOPO combined with OMMT were blended into PP to improve the flame retardancy of the samples. The effects of PN-DOPO/OMMT compounds on the flame retardancy, thermal stability and mechanical properties of the composites and the char morphology of the samples after burning were investigated systematically. When adding 17%PN-DOPO and 3%OMMT, the LOI value for PP/PN-DOPO/ OMMT composites increased to 23.6%, and the UL-94 test reached the V-0 level. The pHRR and THR values of the sample were reduced by 27.5% and 13.0%, respectively, compared with those of PP. TGA showed that the combination of PN-DOPO and OMMT could improve the thermal stability and the content of residues of the PP systems. PN-DOPO/OMMT blends could promote a more continuous and compact structural layer with a high yield of the aluminium–silicate barrier and phosphorus-containing carbonaceous compounds. Furthermore, the PP/PN-DOPO/OMMT composites showed higher tensile strength, flexural properties and impact strength than those of the GFPA6T/PN-DOPO mixtures. In summary, OMMT can be a highly effective and promising synergistic agent to improve the flame retardancy and mechanical properties of flame-retarded PP composites.


Graphene is one of the most promising two-dimensional nanomaterials with broad applications in many fields. However, the variations and fluctuations in the material and geometrical properties are challenging issues that require more concern. In order to quantify uncertainty and analyze the impacts of uncertainty, a stochastic finite element model (SFEM) is proposed to propagate uncertainty for carbon atomic interactions under resonant vibration. Compared with the conventional truss or beam finite element models, both carbon atoms and carbon covalent bonds are considered by introducing plane elements. In addition, the determined values of the material and geometrical parameters are expanded into the related interval ranges with uniform probability density distributions. Based on the SFEM, the uncertainty propagation is performed by the Monte Carlo stochastic sampling process, and the resonant frequencies of graphene are provided by finite element computation. Furthermore, the correlation coefficients of characteristic parameters are computed based on the database of SFEM. The vibration modes of graphene with the extreme geometrical values are also provided and analyzed. According to the computed results, the minimum and maximum values of the first resonant frequency are 0.2131 and 16.894 THz, respectively, and the variance is 2.5899 THz. The proposed SFEM is an effective method to propagate uncertainty and analyze the impacts of uncertainty in the carbon atomic interactions of graphene. The work in this paper provides an important supplement to the atomic interaction modeling in nanomaterials. Graphene is a two-dimensional nanomaterial with promising potential in a wide range of applications. The quantitative analysis methods for the extraordinary properties of graphene mainly include both the experimental and numerical aspects . CompareThe finite element method has long-term development in terms of nonlinear problem solutions, parallel computing, dynamic motion modeling, etc. . The higIn this paper, the stochastic finite element model (SFEM) is proposed for resonant frequency computation and uncertainty propagation. Both the carbon atoms and the carbon covalent bonds are taken into consideration. The method descriptions, including geometrical configuration, material parameters, and computational method, are presented in According to the experimental measurements and observations, the periodic honeycomb lattice of graphene is presented in The assumptions and characteristics of the advanced finite plane element model of graphene are as follows.(a)The finite plane element model projects the precise three-dimensional structure in (b)The finite plane element model is an advanced method with a similar computational competence to the truss and beam finite element model of graphene, as shown in (c)L, 1R, and 2R are the length of the carbon covalent bonds, the radius of the carbon atoms, and twice the width of the carbon covalent bonds, respectively;The related geometrical parameters in the finite plane element model presented in (d)Since the carbon atoms and carbon covalent bonds in graphene are described as different geometrical components, the corresponding material parameters can be assigned to them;(e)The carbon atoms and carbon covalent bonds, as presented in L, 1R, and 2R are equal to 0.27 nm, 0.05 nm, and 0.032 nm, respectively. The typical examples are provided according to the changes in related geometrical parameters. For example, when L is as short as 0.1 nm, the period characteristic hexagon in graphene is presented in L is extruded to 0.4 nm, the period characteristic hexagon in graphene is presented in 2R also evidently impacts the configuration of the period hexagon cell in graphene and then influences the entire intrinsic lattice description. In 2R equals 0.01 nm and 0.04 nm, respectively. Therefore, the proposed geometrical configuration of the finite plane element is flexible to represent different shapes and combinations.In the initial geometrical model of graphene, the values of In addition to the related geometrical parameters in the finite plane element model of graphene, the material parameters are listed in E1 and P1 are presented in R1 and L are presented in The Monte Carlo stochastic simulation propagates the uncertainty of the parameters in the specific value intervals according to the uniform distribution. As presented in The plane element used in the finite element model of graphene is a two-dimensional 8-node quadrilateral element, as shown in u represents the displacement. The fundamental equations are derived from the element formulations and based on the principle of virtual work [ijσ is the Cauchy stress component, V and s are the volumes of the deformed body and the surface of the deformed body on which tractions are prescribed, respectively.The shape functions of the two-dimensional 8-node quadrilateral element in the finite plane element model are expressed as,ual work ,(2)∫vσiW can be indicated by:The internal virtual work Element formulations are obtained by differentiating this virtual work expression. In derivation, only linear differential terms are kept, and all higher-order terms are ignored, so that finally a linear set of equations can be obtained. In addition, the material constitutive law is used to create the relationship between stress increment and strain increment.Therefore, the Cauchy stress rate is:iv is the velocity and ix is the coordinates.According to the constitutive law, the stress change due to straining can be expressed as:The Cauchy stress rate can be written as:The hydrostatic pressure The competitive merits of the finite element model used for the numerical investigation of graphene are the economics of computational cost and feasibility of computation of a massive number of atoms. The resonant frequency computation by the finite plane element model based on Monte Carlo stochastic simulation is programmed in the following flowchart.As shown in Based on the Monte Carlo simulation, the stochastic sampling is performed within the specific interval ranges of the geometrical and material parameters, and the statistical results are presented in Compared with the reported results, the mean values of the resonant frequency of the first vibration mode are evidently larger than the expected value. However, it is worth noting that the minimum resonant frequency of the first vibration mode is as small as 0.2131 THz. In addition, the maximum resonant frequency of the first vibration mode is extended to 16.894 THz. Therefore, the results in the reported references ,21,22,23In order to describe the results more exactly, the probability density distributions of the resonant frequency of the stochastic samples are also presented in the histograms with the fitting curves, as shown in 1R, 2R, and L are the more critical factors to impact the resonant frequency of graphene. In other words, the length and the width of the carbon covalent bonds are essential in the finite plane element model of graphene. This consequence reaches good agreements with the assumption of the reported beam or truss finite element model of graphene [The correlation coefficients of geometrical and material parameters in the finite plane element model of graphene are computed by the Pearson and Spearman methods, as presented in graphene ,11,23. In addition, the widths of the carbon covalent bonds have positive correlation coefficients, while the lengths of the carbon covalent bonds present negative values. For the negative correlation coefficients, the Young’s modulus of carbon atoms in 1R, 2R, and L in 1E and 2E in 1V, 2V, 1P, and 2P present evident variations in Furthermore, the Young’s modulus of carbon covalent bonds has more evident impacts on resonant frequency than that of carbon atoms in In addition to the resonant frequency of graphene, the vibration modes are also computed by the finite plane element model of graphene. According to the above results, the length and width of the carbon covalent bonds are the more important factors influencing the resonant frequency of graphene. The extreme values of the geometrical parameters are introduced in the finite plane element model of graphene to compare the vibration modes. The differences in the vibration modes of the first four resonant vibration modes are presented and compared, as presented in Furthermore, the resonant vibration modes in The proposed stochastic finite plane element model of graphene is an effective alternative to the currently available approaches with competitive competencies in terms of computational performances and result consistency. In short, the following key points can be concluded based on the results.(1)The commonly shared nodes in carbon atoms and carbon covalent bonds in the two-dimensional 8-node quadrilateral element keep the geometrical connection and mechanical compatibility well.(2)The interval ranges of resonant frequencies computed by the finite plane element model completely include the results in the reported literature.(3)The correlation coefficients computed by the Pearson and Spearman methods have substantial agreements with small discrepancies in the geometrical and material parameters.(4)The length and the width of the carbon covalent bonds in the finite plane element model of graphene are the essential factors that impact the resonant frequencies.(5)The proposed finite element model not only has merits in terms of computational expense and feasibility in the massive stochastic sampling process but also is flexible in presenting the precise vibration modes of graphene with consideration of both carbon atoms and covalent bonds.