934 research outputs found

    A review of advancements in synthesis, manufacturing and properties of environment friendly biobased Polyfurfuryl Alcohol Resin and its Composites

    Get PDF
    The quest for environmentally friendly and sustainable materials in the production of fibre reinforced composite materials has led to the use of biobased materials, which are easily accessible and renewable. Biomass-derived chemicals, their derivatives, and their applications have become increasingly prevalent in various industries and processes, greatly contributing to the goal of ecological sustainability. The biobased Polyfurfuryl Alcohol (PFA) resin is one of such polymeric materials that is gaining attention for composite applications due to its endearing Fire Smoke and Toxicity properties. Derived from agricultural by products such as sugar cane bagasse, it has been known for applications within the foundry, coating, and wood industries. However, there has been a growing interest in its use for fibre reinforced composite applications. For this reason, this work intends to provide a comprehensive review of the PFA resin in relationship to fibre reinforced composites applications. The work provides an in-depth discussion on the synthesis, curing process, manufacturing, and properties of the PFA resin as well as its composites

    Bearing performance and damage characteristics of rein-infused thermoplastic 3D woven composites bolted joints

    Get PDF
    This paper presents a comprehensive study on the single-bolt single-shear (SBSS) and double-bolt single shear (DBSS) lap joint performance of resin-infused thermoplastic 3D fibre-reinforced composite (FRC) in on-axis (0°and 90°) and off-axis (45°) configurations. The bearing performance and failure mechanisms are compared with thermoset 3D-FRC. The resin-infused thermoplastic 3D-FRC bolted joint shows improved bearing performance in terms of higher ultimate bearing strength, stiffness loss strength, and reduced damage severity than its thermoset counterpart. Additionally, this paper presents a detailed study on the intermediate and final failure mechanisms, obtained from scanning electron microscopy of the interrupted and ultimate bearing tests, to understand damage progression in SBSS and BDSS lap joints at the submicron level. The major damage characteristics of a thermoplastic 3D-FRC bolted joint include plastic deformation and plastic kinking at the hole front tip, which improve the bearing capacity and reduce stress concentration, damage severity, and its deleterious effects

    Predicting the effect of voids on mechanical properties of woven composites.

    Get PDF
    An accurate yet easy to use methodology for determining the effective mechanical properties of woven fabric reinforced composites is presented. The approach involves generating a representative unit cell geometry based on randomly selected 2D orthogonal slices from a 3D X-ray micro-tomographic scan. Thereafter, the finite element mesh is generated from this geometry. Analytical and statistical micromechanics equations are then used to calculate effective input material properties for the yarn and resin regions within the FE mesh. These analytical expressions account for the effect of resin volume fraction within the yarn (due to infiltration during curing) as well as the presence of voids within the composite. The unit cell model is then used to evaluate the effective properties of the composite.DelPHE 780 Project funded by UK Department of International Development (DFID), through British Council managed DelPHE scheme

    Forming low-cost, high quality carbon tows for automotive application.

    Get PDF
    Carbon fiber reinforced composites are widely used in many industries due to their high performance. Its application in the aerospace industry has increased significantly, however, in mass produced automobile sector it is still limited. The current production of carbon fiber tow is slow and capital intensive. Thus, carbon manufactures produce higher tow counts to increase production rate to reduce its cost. In order to offset the higher cost of carbon fiber composite, an innovative and unique approach has been developed. The higher tow count carbon spools are split into smaller tow counts. Due to the delicate nature of carbon fiber, it is important to control the filamentation during that process. Different splitting process line strategies have been developed in this research work for understanding the process limitations and challenges involved. The process was made feasible for production by developing a fully automated process line with a laser feedback system. The system splits a 12K spool into two 6K tows. The quality of the 6K split tows has been determined statistically by recording real time data from the laser during the splitting process. It was demonstrated that the proposed process effectively controls filamentation and produces consistent tow quality.Company research funding by Bentley Motors Limite

    Prevalence and Profile of Nonalcoholic Fatty Liver Disease in Lean Adults: Systematic Review and Meta-Analysis.

    Get PDF
    Data on prevalence and profile of nonalcoholic fatty liver disease (NAFLD) among individuals who are lean (normal body mass index) is unclear. Published data from studies comparing lean with obese NAFLD or with healthy subjects on prevalence, comorbidities, liver chemistry and histology, and metabolic/inflammatory markers were analyzed. Data were reported as odds ratio and 95% confidence interval for categorical variables and difference of means for continuous variables. Analysis of 53 studies on 65,029 subjects with NAFLD (38,084 lean) and 249,544 healthy subjects showed a prevalence of lean NAFLD at 11.2% in the general population. Among individuals with NAFLD, the prevalence of lean NAFLD was 25.3%. Lean NAFLD versus healthy subjects had higher odds for abnormalities on metabolic profile, including metabolic syndrome and its components, renal and liver function, and patatin-like phospholipase domain-containing protein 3 (PNPLA3) G allele; and inflammatory profile, including uric acid and C-reactive protein. The abnormalities were less severe among lean versus obese NAFLD on metabolic syndrome with its components, renal and liver chemistry, liver stiffness measurement, PNPLA3 and transmembrane 6 superfamily member 2 polymorphisms, and uric acid levels as markers of inflammation. Lean NAFLD had less severe histologic findings, including hepatocyte ballooning, lobular inflammation, NAFLD activity score, and fibrosis stage. Limited data also showed worse outcomes between obese versus lean NAFLD. Conclusion: Lean NAFLD is a distinct entity with metabolic, biochemical, and inflammatory abnormalities compared to healthy subjects and a more favorable profile, including liver histology of steatohepatitis and fibrosis stage, compared to obese NAFLD. We suggest that prospective multicenter studies examine long-term hepatic and extrahepatic outcomes in individuals with lean NAFLD

    An interactive health communication application for supporting parents managing childhood long-term conditions: outcomes of a randomized controlled feasibility trial

    Get PDF
    Background: Families living with chronic or long-term conditions such as chronic kidney disease (CKD), stages 3-5, face multiple challenges and respond to these challenges in various ways. Some families adapt well while others struggle, and family response to a condition is closely related to outcome. With families and professionals, we developed a novel condition-specific interactive health communication app to improve parents’ management ability—the online parent information and support (OPIS) program. OPIS consists of a comprehensive mix of clinical caregiving and psychosocial information and support. Objective: The purpose of this study was to (1) assess feasibility of a future full-scale randomized controlled trial (RCT) of OPIS in terms of recruitment and retention, data collection procedures, and psychometric performance of the study measures in the target population, and (2) investigate trends in change in outcome measures in a small-scale RCT in parents of children with CKD stages 3-5. Methods: Parents were recruited from a pediatric nephrology clinic and randomly assigned to one of two treatment groups: usual support for home-based clinical caregiving (control) or usual support plus password-protected access to OPIS for 20 weeks (intervention). Both groups completed study measures at study entry and exit. We assessed feasibility descriptively in terms of recruitment and retention rates overall; assessed recruitment, retention, and uptake of the intervention between groups; and compared family condition management, empowerment to deliver care, and fathers’ involvement between groups. Results: We recruited 55 parents of 39 children (42% of eligible families). Of those, about three-quarters of intervention group parents (19/26, 73%) and control group parents (22/29, 76%) were retained through completion of 20-week data collection. The overall retention rate was 41/55 (75%). The 41 parents completing the trial were asked to respond to the same 10 questionnaire scales at both baseline and 20 weeks later; 10 scores were missing at baseline and nine were missing at 20 weeks. Site user statistics provided evidence that all intervention group parents accessed OPIS. Analysis found that intervention group parents showed a greater improvement in perceived competence to manage their child’s condition compared to control group parents: adjusted mean Family Management Measure (FaMM) Condition Management Ability Scale intervention group 44.5 versus control group 41.9, difference 2.6, 95% CI -1.6 to 6.7. Differences between the groups in the FaMM Family Life Difficulty Scale (39.9 vs 36.3, difference 3.7, 95% CI -4.9 to 12.2) appeared to agree with a qualitative observation that OPIS helped parents achieve understanding and maintain awareness of the impact of their child’s condition. Conclusions: A full-scale RCT of the effectiveness of OPIS is feasible. OPIS has the potential to beneficially affect self-reported outcomes, including parents’ perceived competence to manage home-based clinical care for children with CKD stage 3-5. Our design and methodology can be transferred to the management of other childhood conditions. Trial Registration: International Standard Randomized Controlled Trial Number (ISRCTN): 84283190; http://www.controlled-trials.com/ISRCTN84283190 (Archived by WebCite at http://www.webcitation.org/6TuPdrXTF)

    Partial pressure of carbon dioxide (pCO2) and air-water CO2 exchange in the tropical semidiurnal estuarine system

    Get PDF
    Time-series observations of the Vellar estuary between May 2013 and December 2019 showed clear variability with respect to space and time in the distribution of nutrients, partial pressure of carbon dioxide (pCO2) and air-water CO2 exchange. Lower and higher salinities revealed significant seasonality in estuarine pCO2, as well as variations in the seasonal pattern due to the freshwater discharges during monsoon rainfall. The pCO2 attained the highest levels (8457 µatm) during monsoon which coincided with the lowest pH (7.498) and the undersaturation of pCO2 (322 µatm) was observed with maximum pH (8.182) during pre-monsoon. The Principal Component Analysis (PCA) identified four components that accounted for 77.28 % of the total variance and explained the significant influence of nutrients, chlorophyll and temperature on pCO2 distribution. Similarly, the multiple linear regression analysis showed significant influence of environmental variables on pCO2 variability with a R2 of 0.957, SEE±230.816, p < 0.001. The surveyed area of the Vellar estuary had an overall pCO2 of 1068 µatm and was supersaturated with regard to the atmospheric pCO2 throughout the year, with an average CO2 flux of 4.13±5.59 mmol C m-2 d-1 to the atmosphere. During the study period, the Vellar estuary actively supplied 650.2 mol C m-2 Y-1 to the atmosphere. Hence, the metabolic balance of the estuarine ecosystem is aided by land derived organic carbon accompanied with freshwater flows from the Vellar river, constituting the estuary as a substantial source of atmospheric CO2

    Bounds for Lepton Flavor Violation and the Pseudoscalar Higgs in the General Two Higgs Doublet Model using g−2g-2 muon factor

    Full text link
    Current experimental data from the g−2g-2 muon factor, seems to show the necessity of physics beyond the Standard Model (SM), since the difference between SM and experimental predictions is 2.6σ\sigma . In the framework of the General Two Higgs Doublet Model (2HDM), we calculate the muon anomalous magnetic moment to get lower and upper bounds for the Flavour Changing (FC) Yukawa couplings in the leptonic sector. We also obtain lower bounds for the mass of the pseudoscalar Higgs (mA0m_{A^0}) as a function of the parameters of the model.Comment: 12 pages, RevTex4, 5 figures. Improved presentation, updated experimental data, amplified analysis, new figures added. Subbmited to Phys. Rev.

    Snapshot PCR surveillance for SARS-CoV-2 in hospital staff in England

    Get PDF
    Background: Significant nosocomial transmission of SARS-CoV-2 has been demonstrated. Understanding the prevalence of SARS-CoV-2 carriage amongst HCWs at work is necessary to inform the development of HCW screening programmes to control nosocomial spread. / Methods: Cross-sectional ‘snapshot’ survey from April-May 2020; HCWs recruited from six UK hospitals. Participants self-completed a health questionnaire and underwent a combined viral nose and throat swab, tested by Polymerase Chain Reaction (PCR) for SARS-CoV-2 with viral culture on majority of positive samples. / Findings: Point prevalence of SARS-CoV-2 carriage across the sites was 2.0% (23/1152 participants), median cycle threshold value 35.70 (IQR:32.42–37.57). 17 were previously symptomatic, two currently symptomatic (isolated anosmia and sore throat); the remainder declared no prior or current symptoms. Symptoms in the past month were associated with threefold increased odds of testing positive (aOR 3.46, 95%CI 1.38–8.67; p = 0.008). SARS-CoV-2 virus was isolated from only one (5%) of nineteen cultured samples. A large proportion (39%) of participants reported symptoms in the past month. / Interpretation: The point-prevalence is similar to previous estimates for HCWs in April 2020, though a magnitude higher than in the general population. Based upon interpretation of symptom history and testing results including viral culture, the majority of those testing positive were unlikely to be infectious at time of sampling. Development of screening programmes must balance the potential to identify additional cases based upon likely prevalence, expanding the symptoms list to encourage HCW testing, with resource implications and risks of excluding those unlikely to be infectious with positive tests. / Funding: Public Health England
    • …
    corecore