Effects of nonlinear thermal radiation on the efficiency of building integrated photovoltaic systems with nanofluid cooling.

The nonlinear effects of thermal radiation on the free convection flow of certain nanofluids along a heated wall are studied numerically using an original finite-difference method. Nanofluids are used to improve the performance of flat and curved integrated photovoltaic modules. The partial differential equations governing the flow are difficult to solve due to the strong non-linearity of the radiative term. In contrast to previous studies, the problem is solved directly without linearization by Rosseland's nonlinear approximation. The proposed numerical method is validated with results from the literature. The effects of nonlinearity and various physical parameters such as time, volume fraction and radiation parameter on the velocity, temperature, Nusselt number and skin friction coefficient of the CuO-water nanofluid are analyzed and presented graphically. A comparative study between the solutions given by the linear and non-linear problems reveals that Rosseland's linear approximation is no longer valid when the effect of thermal radiation is significant. On the other hand, the non-linear model better reflects the physical phenomena involved in the cooling process. Finally, a comparison of the performance of five nanofluids (CuO, Ag, Al2O3, Cu and TiO2 in water) shows that the Cu-water nanofluid performs best, with a high heat transfer rate and low shear stresses.

Comprehensive pan-cancer analysis reveals VSIR as a candidate immunologic, diagnostic, and prognostic biomarker.

OBJECTIVES: Being a checkpoint, the expression level of V-set immunoregulatory receptor (VSIR) serves as an indicator of the extent of immunosuppression. Our objective was to undertake a pan-cancer analysis to examine the expression, genetic alterations, prognosis, and immunologic features associated with VSIR. METHODS: The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), GEPIA2, UALCAN, OncoDB, Human Protein Atlas (HPA), STRING, DAVID, cell culture, clinical sample collection, and reverse transcription quantitative polymerase chain reaction (RT-qPCR) were used. RESULTS: This study comprehensively assessed VSIR across 33 cancers using TCGA and GTEx databases. Differential expression analysis revealed elevated VSIR in several cancers, notably in cholangiocarcinoma, esophageal carcinoma, kidney renal cell carcinoma, and liver hepatocellular carcinoma, while decreased expression was observed in various others. Prognostic analysis highlighted its significant association with reduced overall survival (OS) in ESCA and LIHC. Investigation into cancer stages demonstrated a correlation between VSIR expression and stage in ESCA and LIHC. Promoter methylation analysis indicated decreased VSIR methylation levels in tumors, implicating a role in oncogenesis. Furthermore, subcellular localization predictions, Tumor Mutational Burden (TMB), and Microsatellite Instability (MSI) correlations revealed intriguing insight into VSIR's function. Notably, a positive correlation was identified between VSIR expression and various immune cells in both cancers. Protein-protein interaction (PPI) network construction and gene enrichment analysis elucidated VSIR-associated dysregulated pathways, emphasizing its possible involvement in diverse pathways. Finally, experimental validation using LIHC clinical samples and cell lines confirmed elevated VSIR expression, supporting its oncogenic role. CONCLUSION: Collectively, these findings present a comprehensive understanding of VSIR's diverse roles and potential clinical implications in ESCA and LIHC.

Unveiling the unexplored novel signatures for osteoporosis via a detailed bioinformatics and molecular experiments based approach.

BACKGROUND: Osteoporosis (OP) stands as a prevalent bone ailment affecting the elderly, globally. The identification of reliable diagnostic markers crucially aids OP clinical management. METHODS: Utilizing the GEO database (GSE35959), we acquired expression profiles for OP and normal samples. Differential expression genes (DEGs) and hub genes were pinpointed through STRING, GEO2R, and Cytoscape. The competing endogenous RNA (ceRNA) network was constructed using miRTarBase, miRDB, and MiRcode databases. Gene Ontology (GO) and KEGG pathway enrichment analyses were performed via DAVID. Validation involved clinical OP samples from the Pakistani population, with Real-Time Quantitative Polymerase Chain Reaction (RT-qPCR) assessing hub gene expression. RESULTS: A total of 2124 differentially expressed genes (DEGs) were identified between OP and normal samples in GSE35959. The selected hub genes among these DEGs were Splicing Factor 3a Subunit 1 (SF3A1), Ataxin 2 Like (ATXN2L), Heat Shock Protein 90 Beta Family Member 1 (HSP90B1), Cluster of Differentiation 74 (CD74), DExH-Box Helicase 29 (DHX29), ALG5 Dolichyl-Phosphate Beta-Glucosyltransferase (ALG5), NudC Domain Containing 2 (NUDCD2), and Ras-related protein Rab-2A (RAB2A). Expression validation of these genes on the Pakistani OP patients revealed significant up-regulation of SF3A1, ATXN2L, and CD74 and significant (P < 0.05) down-regulation of HSP90B1, DHX29, ALG5, NUDCD2, and RAB2A in OP patients. Receiver operating characteristic (ROC) analysis demonstrated that these hub genes displayed considerable diagnostic accuracy for detecting OP. The ceRNA network analysis of the hub genes revealed some important hub genes' regulatory miRNAs and lncRNAs. Via KEGG analysis, hub genes were found to be enriched in N-Glycan biosynthesis, Thyroid hormone synthesis, IL-17 signaling pathway, Prostate cancer, AMPK signaling pathway, Spliceosome, Estrogen signaling pathway, and Fluid shear stress and atherosclerosis, etc., pathways. CONCLUSION: The identified eight hub genes in the present study could reliably distinguish OP patients from normal individuals, which may provide novel insight into the diagnostic research of OP.

Transcriptomics data integration and analysis to uncover hallmark genes in hypertrophic cardiomyopathy.

INTRODUCTION: Hypertrophic cardiomyopathy (HCM) is a heterogeneous disease that mainly affects the myocardium. In the current study, we aim to explore HCM-related hub genes through the analysis of differentially expressed genes (DEGs) between HCM and normal sample groups. METHODS: The GSE68316 and GSE36961 expression profiles were obtained from the Gene Expression Omnibus (GEO) database for the identification of DEGs, to explore hub genes, and to perform their expression analysis. Clinical HCM and control tissue samples were taken for expression and promoter methylation validation analysis via RNA-sequencing (RNA-seq) and targeted bisulfite sequencing (bisulfite-seq) analyses. Then, other different bioinformatics tools were employed to perform STRING, lncRNA-miRNA-mRNA regulatory networks, gene enrichment, and drug prediction analyses. RESULTS: In total, the top 20 DEGs, including 10 up-regulated and 10 down-regulated, were obtained from GSE68316. Out of the 20 DEGs, we subsequently identified the 8 most important hub genes including 5 up-regulated genes (EPB42, UQCRH, CA1, PFDN5, and LSM5) and 3 down-regulated genes (RPS24, TNS1, and RPL26). Expression and promoter methylation dysregulation of these genes were further validated on clinical HCM samples paired with controls. Next, we further investigated hub genes' regulatory 6 miRNAs (has-mir-1-3p, has-mir-129-5p, has-mir-16-5p, has-mir-23b-3p, has-mir-27-3p, and has-mir-182-5p) and miRNAs regulatory 4 lncRNAs (NUTMB2-AS1, NEAT1, XIST, and GABPB1-AS1) in this study via the lncRNA-cricRNA-miRNA-mRNA regulatory network. Later on, gene enrichment analysis revealed that hub genes were enriched in various important pathways including Nitrogen metabolism, Ribosome, RNA degradation, Cardiac muscle contraction, and Coronavirus disease, etc. Finally, the drug prediction analysis highlighted different potential candidate drugs for altering the expression of hub genes in the treatment of HCM. CONCLUSION: In summary, the identification of key hub genes and their enrichment analysis in the current study may shed light on the mechanisms behind the occurrence and development of HCM.

Continuity of care in primary healthcare settings among patients with chronic diseases in Saudi Arabia.

Introduction: Maintaining continuity of care is one of the most critical components of providing great care in primary health care. This study aimed to explore continuity of care and its predictors in primary healthcare settings among patients with chronic diseases in Saudi Arabia. Method: Face-to-face cross-sectional interviews were conducted with patients with chronic diseases who had at least four visits to primary care facilities in Riyadh, Saudi Arabia, between November 1, 2022 and March 3, 2023. We determined patients' continuity of care levels using the Bice-Boxerman continuity of care index. A Tobit regression model was used to determine the effects of several factors on the continuity of care index. Results: The interviews were conducted with 193 respondents with chronic diseases of interest. The mean continuity of care index of the entire sample was 0.54. Those with asthma had the highest median continuity of care index at 0.75 (interquartile range, 0.62-0.75), whereas those diagnosed with thyroid disease had a much lower continuity of care index (0.47) (interquartile range, 0.3-0.62). Tobit regression model findings showed that employed respondents with poorer general health had a negative effect on continuity of care index levels. By contrast, a higher continuity of care index was significantly associated with elderly respondents, urban residents, and those diagnosed with dyslipidemia, diabetes, hypertension, or asthma. Conclusions: According to our findings, the continuity of care level in Saudi Arabia's primary healthcare setting is low. The data demonstrate how continuity of care varies among study group characteristics and that improving continuity of care among chronic disease patients in Saudi Arabia is multifaceted and challenging, necessitating a coordinated and integrated healthcare delivery approach.

Hypnic Jerks, Major Depressive Disorder, and Antidepressant Use: A Possible Relationship.

The term hypnic jerks (also known as sleep starts or hypnagogic jerks) refers to a physiological phenomenon that accompanies sleep-wake transitions and can occur in healthy individuals of any age. Various physiological and stressful stimuli can precipitate hypnic jerks and contribute to their frequency and amplitude, e.g., stress, fatigue, stimulants like caffeine, and certain medications. Hypnic jerks are usually benign, but they can be intensified in certain situations, interfering with sleep onset and causing insomnia. Here we reported the case of a patient who suffered from intensified hypnic jerks that led to the development of major depressive disorder. Although the depressive symptoms improved on escitalopram 20 mg, the hypnic jerks increased significantly. Clonazepam was found to be very effective in reducing the hypnic jerks and stabilizing his condition.

Post-traumatic Stress Disorder and Its Associated Risk Factors Among Emergency Healthcare Workers: A Saudi Cross-Sectional Analytical Study.

BACKGROUND: Post-traumatic stress disorder (PTSD) is a psychiatric disease characterized by exposure to threatened death or serious injury and directly experiencing or witnessing the event. Many healthcare professionals have had PTSD, but emergency physicians may be particularly susceptible. To our knowledge, no study has been performed in Saudi Arabia to identify the prevalence and associated risk factors of PTSD among emergency staff. OBJECTIVE: This study aims to determine the prevalence and risk factors of post-traumatic stress disorder (PTSD) among emergency healthcare workers (HCWs) in Saudi Arabia. METHODS: A cross-sectional analytical study will be conducted in emergency departments around Saudi Arabia in all regions. The study population will include healthcare workers in emergency departments who work and presently live in Saudi Arabia. The survey was divided into two sections. The first section focuses on the emergency personnel's demographic data; the second concentrates on screening for post-traumatic stress disorder using the PTSD checklist for DSM-5 (PCL-5). RESULTS: Our population included 519 emergency healthcare staff, including males (51.4%) and females (48.6%). Most emergency HCWs worked in the Ministry of Health Hospitals (58%). The highest diagnosed psychological disorders among emergency staff were anxiety (19.3%) and mood disorders (10.2%). The prevalence of PTSD among emergency workers in Saudi Arabia was 14.1%. The prevalence of PTSD was significantly higher among emergency HCWs who had chronic diseases, emergency workers with anxiety or mood disorders, emergency staff who were using psychiatric medication (p<0.001), and those with psychotic disorders (p=0.002). CONCLUSION: The prevalence of PTSD among emergency healthcare workers in Saudi Arabia is estimated to be 14.1%, and pre-existing mental illnesses are associated with a higher risk of PTSD.

Enhanced and Proficient Soft Template Array of Polyaniline-TiO2 Nanocomposites Fibers Prepared Using Anionic Surfactant for Fuel Cell Hydrogen Storage.

Porous TiO2-doped polyaniline and polyaniline nanocomposite fibers prepared by the in situ polymerization technique using anionic surfactant in an ice bath were studied. The prepared nanocomposites were characterized by FTIR spectroscopy and XRD patterns for structural analysis. The surface morphology of the polyaniline and its nanocomposites was examined using SEM images. DC conductivity shows the three levels of conductivity inherent in a semiconductor. Among the nanocomposites, the maximum DC conductivity is 5.6 S/cm for 3 wt.% polyaniline-TiO2 nanocomposite. Cyclic voltammetry shows the properties of PANI due to the redox peaks of 0.93 V and 0.24 V. Both peaks are due to the redox transition of PANI from the semiconductor to the conductive state. The hydrogen absorption capacity is approximately 4.5 wt.%, but at 60 °C the capacity doubles to approximately 7.3 wt.%. Conversely, 3 wt.% PANI-TiO2 nanocomposites have a high absorption capacity of 10.4 wt.% compared to other nanocomposites. An overall desorption capacity of 10.4 wt.% reduced to 96% was found for 3 wt.% TiO2-doped PANI nanocomposites.

In vitro analysis of PI3K pathway activation genes for exploring novel biomarkers and therapeutic targets in clear cell renal carcinoma.

OBJECTIVES: The regulation of various cellular functions such as growth, proliferation, metabolism, and angiogenesis, is dependent on the PI3K pathway. Recent evidence has indicated that kidney renal clear cell carcinoma (KIRC) can be triggered by the deregulation of this pathway. The objective of this research was to investigate 25 genes associated with activation of the PI3K pathway in KIRC and control samples to identify four hub genes that might serve as novel molecular biomarkers and therapeutic targets for treating KIRC. METHODS: Multi-omics in silico and in vitro analysis was employed to find hub genes related to the PI3K pathway that may be biomarkers and therapeutic targets for KIRC. RESULTS: Using STRING software, a protein-protein interaction (PPI) network of 25 PI3K pathway-related genes was developed. Based on the degree scoring method, the top four hub genes were identified using Cytoscape's Cytohubba plug-in. TCGA datasets, KIRC (786-O and A-498), and normal (HK2) cells were used to validate the expression of hub genes. Additionally, further bioinformatic analyses were performed to investigate the mechanisms by which hub genes are involved in the development of KIRC. Out of a total of 25 PI3K pathway-related genes, we developed and validated a diagnostic and prognostic model based on the up-regulation of TP53 (tumor protein 53) and CCND1 (Cyclin D1) and the down-regulation of PTEN (Phosphatase and TENsin homolog deleted on chromosome 10), and GSK3B (Glycogen synthase kinase-3 beta) hub genes. The hub genes included in our model may be a novel therapeutic target for KIRC treatment. Additionally, associations between hub genes and infiltration of immune cells can enhance comprehension of immunotherapy for KIRC. CONCLUSION: We have created a new diagnostic and prognostic model for KIRC patients that uses PI3K pathway-related hub genes (TP53, PTEN, CCND1, and GSK3B). Nevertheless, further experimental studies are required to ascertain the efficacy of our model.

The impact of low self-esteem on academic achievement and the behaviors related to it among medical students in Saudi Arabia.

OBJECTIVES: To measure the prevalence of low self-esteem among medical students in Saudi Arabia and determine its impact on their behaviors and academic achievement. METHODS: We hypothesized that the level of self-esteem reflected on the student's academic performance and linked to some of their behaviors. A cross-sectional study was carried out among students of the medical colleges in Saudi Arabia. A self-administered questionnaire was distributed electronically using social media platforms, socio-demographic data, Rosenberg's self-esteem scale, and a questionnaire about self-esteem-related behaviors. RESULTS: Of 1099 participants (55.9% females and 50% males), 24.1% showed low self-esteem. Independent significant predictors of low self-esteem were female gender and diagnosis with mental illness. Increasing GPA was associated with better self-esteem. Participating in students' study groups and attending self-development programs were estimated to be the protective factors against low self-esteem. CONCLUSION: One-quarter of medical students are assumed to have low self-esteem. Improved GPA ratings positively influence self-esteem, while attending students' study groups and self-development programs were identified as protective factors for low self-esteem. Further studies are needed to shed more light on this important topic.

Screening of four signature genes for clinical testing through bioinformatics and in vitro methods in head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSC) is the 6th most common cancer around the globe; its underlying molecular mechanisms and accurate molecular markers are still lacking. In this study, we explored hub genes and their potential signaling pathways through which these genes participate in the development of HNSC. The GSE23036 gene microarray dataset was attained from the GEO (Gene Expression Omnibus) database. Hub genes were identified via the Cytohubba plug-in application of the Cytoscape. The Cancer Genome Atlas (TCGA) datasets and cell lines (HOK and FuDu) were used to evaluate expression variations in the hub genes. Moreover, promoter methylation, genetic alteration, gene enrichment, miRNA network, and immunocyte infiltration analysis were also performed to confirm the oncogenic role and biomarker potential of the hub genes in HNSC patients. Based on the hub gene analysis results, four hub genes, including KNTC1 (Kinetochore Associated 1), CEP55 (Centrosomal protein of 55 kDa), AURKA (Aurora A Kinase), and ECT2 (Epithelial Cell Transforming 2), with the highest degree scores were denoted as hub genes. All these four genes were significantly up-regulated in HNSC clinical samples and cell lines relative to their counterparts. Overexpression of KNTC1, CEP55, AURKA, and ECT2 was also associated with poor survival and various clinical parameters of the HNSC patients. Methylation analysis through targeted bisulfite sequencing of HOK and FuDu cell lines revealed that the overexpression of KNTC1, CEP55, AURKA, and ECT2 hub genes was due to their promoter hypomethylation. Moreover, higher expressions of KNTC1, CEP55, AURKA, and ECT2 were positively correlated with the abundance of the CD4+ T cells and macrophage while with the reduction of CD8+ T cells in HNSC samples. Finally, gene enrichment analysis showed that all hub genes are involved in "nucleoplasm, centrosome, mitotic spindle, and cytosol" pathways. In conclusion, the KNTC1, CEP55, AURKA, and ECT2 genes could be potential biomarkers for HNSC patients and provide a novel insight into the diagnosis and treatment of the disease.

Onsite enhancement of REEEC solar photovoltaic performance through PCM cooling technique.

The efficiency of solar panels decreases as the temperature increases and heat dissipation becomes a serious problem in hot environments such as the Arabian desert. This paper investigates the use of a phase change material (PCM-OM37P) to maintain panel temperatures close to ambient. The enhancement of the GCL-P6/60265W solar panel efficiency was demonstrated at the University of Tabuk Renewable Energy and Energy Efficiency Center (REEEC). As these solar panel arrays are remotely monitored, we were able to demonstrate the validity of our cooling solution. During peak times, a drop voltage of at least 0.6V has been realized using the PCM for cooling the PV panel. This corresponds to a cooling temperature of 5 to 6°C. This difference in operating voltages between the PCM-cooled and the reference PV panels translates into a power enhancement percentage (PEP) of about 3%. The PEP value was underestimated due to the PV string configuration where the operating electrical current is taken as the average value for both PV panels.

Thermal effect on curved photovoltaic panels: Model validation and application in the Tabuk region.

This paper aimed to investigate the temperature effect on photovoltaic (PV) cell parameters. The PV cell parameters such as series and parallel resistances, diode ideality factor, and diode saturation current, are not considered in the reported stepwise modeling. The present work aims to improve available models used in the modeling and simulation of PV modules to support the researcher and power project developer. All the required temperature-dependent parameters are determined to model the simulated PV module with high accuracy using Simulink/MATLAB software. To validate the method, a 36-cell-50W solar panel with different radii of curvature is set up to assess solar power outputs under varying irradiance and temperature conditions. For the present application, the Tabuk region (Saudi Arabia) is chosen based on its location and climatic conditions. The method provided conformity to the measured power outputs for varying Global Horizontal Irradiance (GHI) and temperature conditions. The maximum power output of the PV module increases from 14.4 W to 25.8 W when the received solar power density varies from 307 W/m2 to 526 W/m2 depending on the level of curvature starting from a semi-cylindrical shape to a vaulted shape to a flat shape. The curved PV module shows slightly higher power variation with temperature as compared to the flat one. Above 25°C, the power output is about 20% less at a maximum temperature of 65°C. When the temperature drops below 25°C, the power outputs increase about 6% and 11.5% for corresponding temperatures of 15°C and 5°C, respectively.

Prevalence of pharmacological and non-pharmacological coping mechanisms for anxiety management during the COVID-19 pandemic: investigating the transition to online learning among medical students.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic had a devastating effect on college students worldwide. Here, the authors aimed to determine the prevalence of anxiety and its related coping strategies, provide a theoretical basis for understanding self-prescription, and identify the factors contributing to stress and anxiety in medical students during the pandemic. METHODS: The authors conducted a cross-sectional study among medical students in Saudi Arabia from September to November 2020. They assessed anxiety using the GAD-7 scale based on seven core symptoms. The authors also examined perceived psychological stress using a single-item measure of stress, the factors contributing to stress during the transition to online learning and examinations, and related coping strategies. The Statistical Package for Social Sciences (SPSS) version 26.0 was used to examine the data for both descriptive and inferential analyses. Chi-square test, one-way ANOVA, and univariate linear regression were used to test the research hypotheses. RESULTS: The authors collected and analyzed data from 7116 medical students distributed across 38 medical colleges. Among them, 40% reported moderate to severe anxiety symptoms. Pre-clinical and female students experienced more stress than clinical and male students. 12.19% (n = 868) of respondents reported using medication during their college years. Among those, 58.9% (n = 512) had moderate to severe anxiety, and the most commonly used drug was propranolol (45.4%, n = 394). Among the studied sample, 40.4% (n = 351) decreased their medication use after switching to online teaching. Most students used these medications during the final exam (35.8%, n = 311) and before the oral exam (35.5%, n = 308). In terms of coping strategies, males were much more likely to use substances than females, who mainly resorted to other strategies. CONCLUSIONS: This study provides a national overview of the impact of COVID-19 on the mental health of medical students. The results indicated that the pandemic is associated with highly significant levels of anxiety. These findings can provide theoretical evidence for the need for supportive psychological assistance from academic leaders in this regard.

Prevalence and associated factors of alexithymia among medical students: A cross-sectional study from Saudi Arabia.

OBJECTIVES: To assess the prevalence of alexithymia and its associated factors among medical students at King Saud University (KSU), Riyadh, Kingdom of Saudi Arabia. METHODS: A cross-sectional study was conducted at KSU, including 420 medical students from all years of medical college (i.e., first to the fifth year), by using an electronic questionnaire distributed during August 2021. The questionnaire consisted of sociodemographic-related questions and the 20-item Toronto alexithymia scale (a validated scale in the literature). RESULTS: The prevalence of alexithymia among the participants was found to be 26.9%. A statistically significant association between alexithymia and gender (p=0.013) was found. A diagnosis with any psychiatric condition (p=0.026), history of abuse during childhood (p=0.006), and lack of physical activity were associated with alexithymia. CONCLUSION: The prevalence of alexithymia among medical students at KSU was significantly higher than general population in literatures. It was indicated in the results that being female, having a psychiatric condition or history of childhood abuse, and lack of physical activity were all associated with alexithymia. We recommend increasing awareness of and screening for alexithymia and its associated factors among medical students.

New Insights into Listeria monocytogenes Antimicrobial Resistance, Virulence Attributes and Their Prospective Correlation.

Listeriosis is one of the most common foodborne diseases caused by Listeria monocytogenes (L. monocytogenes). A poor prognosis has been recorded for the invasive listeriosis, especially neurolisteriosis. In several countries throughout the world, foodborne infections with L. monocytogenes exceeded the legal safety limits in animal sourced foods. Therefore, we decided to investigate the variability, virulence and antimicrobial resistance profiles of this pathogen. Both phenotypic and genotypic methods were used for identifying L. monocytogenes isolates and confirming their virulence profiles. The antimicrobial resistances and their correlation analysis with the existence of virulence genes were detected. Additionally, sequencing and phylogenetic analysis based on L. monocytogenes inlA and inlB genes were undertaken. The prevalence rate (11.9%) and the resistance profiles of L. monocytogenes were shocking. The multi-drug resistance (MDR) phenotypes were common among our isolates (64.9%). Fortunately, the resistance phenotypes were always associated with low virulence arrays and the MDR strains possessed low virulence fitness. Herein, the high genotypic and phenotypic diversity of L. monocytogenes isolates and their weak clonality and adaptability highlighted the difficulty in controlling and managing this pathogen. Therefore, it is important to add more restriction guidelines from national authorities on the consumption of ready to eat foods.

Synthesis of Starch-Grafted Polymethyl Methacrylate via Free Radical Polymerization Reaction and Its Application for the Uptake of Methylene Blue.

In this research, a new biodegradable and eco-friendly adsorbent, starch-grafted polymethyl methacrylate (St-g-PMMA) was synthesized. The St-g-PMMA was synthesized by a free radical polymerization reaction in which methyl methacrylate (MMA) was grafted onto a starch polymer chain. The reaction was performed in water in the presence of a potassium persulfate (KPS) initiator. The structure and different properties of the St-g-PMMA was explored by FT-IR, 1H NMR, TGA, SEM and XRD. After characterization, the St-g-PMMA was used for the removal of MB dye. Different adsorption parameters, such as effect of adsorbent dose, effect of pH, effect of initial concentration of dye solution, effect of contact time and comparative adsorption study were investigated. The St-g-PMMA showed a maximum removal percentage (R%) of 97% towards MB. The other parameters, such as the isothermal and kinetic models, were fitted to the experimental data. The results showed that the Langmuir adsorption and pseudo second order kinetic models were best fitted to experimental data with a regression coefficient of R2 = 0.93 and 0.99, respectively.

Fabrication and Characterization of Flexible Solid Polymers Electrolytes for Supercapacitor Application.

In this work, solid flexible polymer blend electrolytes (PBE) composed of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) with different amounts of sodium thiocyanate (NaSCN) salt mixed in double-distilled water (solvent) are prepared via solution casting method. The obtained films are characterized using several techniques. The study of the surface morphology of the polymer blend salt complex films via the POM technique reveals the presence of amorphous regions due to the NaSCN effect. FTIR spectra studies confirm the complex formation between PVA, PVP, and NaSCN. The addition of 20 wt% NaSCN salt in the composition PVA: PVP (50:50 wt%) polymer blend matrix leads to an increase in the number of charge carriers and thus improves the ionic conductivity. The ionic conductivity of each polymer blend electrolyte was studied using the electrochemical impedance spectroscopy (EIS) method. The highest room temperature ionic conductivity of 8.1 × 10-5 S/cm S cm-1 is obtained for the composition of PVA: PVP (50:50 wt%) with 20 wt% NaSCN. LSV test shows the optimized ion-conducting polymer blend electrolyte is electrochemically stable up to 1.5 V. TNM analysis reveals that 99% of ions contribute for the conductivity against 1% of electrons only in the highly conductive polymer electrolyte PVA: PVP (50:50 wt%) + 20 wt% NaSCN. A supercapacitor device was fabricated using the optimized ion-conducting polymer blend film and graphene oxide (GO) coated electrodes. The GCD curve clearly reveals the behavior of an ideal capacitor with less Faradic process and low ESR value. The columbic efficiency of the GO-based system is found to be 100%, the GO-based electrode exhibits a specific capacitance of 12.15 F/g and the system delivers the charge for a long duration. The specific capacitance of the solid-state supercapacitor cell was found to be 13.28 F/g via the CV approach close to 14.25 F/g obtained with EIS data at low frequency.

The Impact of Polymer Electrolyte Properties on Lithium-Ion Batteries.

In recent decades, the enhancement of the properties of electrolytes and electrodes resulted in the development of efficient electrochemical energy storage devices. We herein reported the impact of the different polymer electrolytes in terms of physicochemical, thermal, electrical, and mechanical properties of lithium-ion batteries (LIBs). Since LIBs use many groups of electrolytes, such as liquid electrolytes, quasi-solid electrolytes, and solid electrolytes, the efficiency of the full device relies on the type of electrolyte used. A good electrolyte is the one that, when used in Li-ion batteries, exhibits high Li+ diffusion between electrodes, the lowest resistance during cycling at the interfaces, a high capacity of retention, a very good cycle-life, high thermal stability, high specific capacitance, and high energy density. The impact of various polymer electrolytes and their components has been reported in this work, which helps to understand their effect on battery performance. Although, single-electrolyte material cannot be sufficient to fulfill the requirements of a good LIB. This review is aimed to lead toward an appropriate choice of polymer electrolyte for LIBs.

Interlayer Defect Detection in Intra-Ply Hybrid Composite Material (GF/CF) Using a Capacitance-Based Sensor.

Combining two types of reinforcement fiber in a common matrix may lead to different failure modes such as micro-cracks between the layers when the structure is subjected to lower stress levels. Real-time damage detection should be integrated into the hybrid composite structure to provide structural integrity and mitigate this problem. This paper outlines the working mechanisms and the fabrication of an integrated capacitive sensor in an intra-ply hybrid composite (2 × 2 twill weave). Uniaxial tensile and flexural tests were conducted to characterize the proposed sensor and provide self-sensing functionality (smart structure). The sensitivity and repeatability of the capacitive sensor were measured to be around 1.3 and 185 µΔC/Co, respectively. The results illustrate that onset of damage between layers can be detected by in situ monitoring. It can be seen that the initial damage was detected at the turning point where the relative change in capacitance begins to reduce while the load increases. Finite element modeling was also constructed to analyze the test results and explain the reasons behind the turning point. It was shown that the carbon yarns experienced high transverse shear stress (τxz) in the crimp region, leading to inter-fiber cracks.