An efficient metal-free hydrophilic carbon as a counter electrode for dye-sensitized solar cells

This study presents a new cost-effective metal-free counter electrode (CE) for dye-sensitized solar cells (DSSCs). CE was prepared by doctor blading a hydrophilic carbon (HC) particle on a fluorine-doped tin oxide substrate. Thereafter, HC CE was characterized using X-ray diffraction, profilometry, four-point probe testing, and cyclic voltammetry. A 2 μm thick HC CE revealed a comparable catalytic activity to that of the Pt electrode under the same experimental conditions. DSSC based on HC CE was analyzed and showed J s c of 6.87 mA/cm2 close to that of DSSC with Pt CE (7.0 mA/cm2). More importantly, DSSC based on HC CE yielded a power conversion efficiency (η) of 2.93% under AM 1.5 irradiation (100 mW/cm2), which was comparable to that of DSSC based on standard Pt CE. These findings suggest that HC CE could be a promising CE for low-cost DSSCs

Comparison of spatial auto correlation analysis methods for investigating the distribution pattern of diabetes type II patients in Iskandar Malaysia

Spatial statistics have been widely used in epidemiology studies in order to investigate and monitor the outbreak in endemic area. However, there is less application of spatial statistics in the study on built environment and diseases outbreak. It is significant to conduct such a study since non-communicable diseases have been rising over past four decades and have a strong positive relation to the built environment, particularly in the rapid urbanizing area. Therefore, this study aims to measure the geographical distribution and determine the pattern of the patients in urbanizing area. Two methods of Moran’s I and Getis-Ord G Statistics, that have been used extensively in the epidemiology are compared on diabetes type II patients data both in global and local scales. A total of 496 patients diagnosed with diabetes type II in 154 neighbourhoods of Iskandar Malaysia (IM) have been evaluated. This study compares the results of two methods based on built environment criteria. The study evaluates their applicability is such a study to identify the best method and scale to be considered in study on built environment-related epidemiology

Optimization of dye extraction from Cordyline fruticosa via response surface methodology to produce a natural sensitizer for dye-sensitized solar cells

AbstractIn the present work, the application of response surface methodology (RSM) for the optimization of process parameters in the chlorophyll extraction from Cordyline fruticosa leaves was performed. The absorbance of the extract obtained from the extraction process under different conditions was estimated using the D-optimal design in RSM. Three different process parameters such as the nature of organic solvent based on their boiling point (ethanol, methanol, and acetonitrile), pH (4–8) and extraction temperature (50–90°C) were optimized for chlorophyll extraction. The effects of these parameters on the absorbance or concentration of the extract were evaluated using ANOVA results of quadratic polynomial regression. The results showed a high R2 and adjusted R2 correlation coefficients of 0.9963 and 0.9921 respectively. Moreover, the analysis of the final quadric model based on the design experiments indicated an optimal extraction condition of pH of 7.99, extraction temperature of 78.33°C, and a solvent boiling point, 78°C. The predicted absorbance was 1.006, which is in good agreement with the experimentally obtained result of 1.04 at 665nm wavelength. The application of pigment obtained under the optimal condition was further evaluated as a sensitizer for the dye sensitized solar cells. Maximum solar conversion efficiency (η) of 0.5% was achieved for the C. fruticosa leaf extract obtained under the optimum extraction conditions. Furthermore, the exposure of the leaf pigment to 100mW/cm2 simulated sunlight yielded a short circuit photocurrent density (Isc) of 1.3mA, open circuit voltage (Voc) of 616mV, and a fill factor (ff) of 60.16%

Hierarchical multiple regression modelling on predictors of neighbourhood satisfaction in violence-induced segregated urban environments

Violence-induced segregated urban environments (VISUE) are quite unique urban centres for their characteristic of neighbourhood sharing among residents before the resultant parting triggered by violence. Yet, not much is known about the neighbourhood satisfaction of inhabitants in this type of urban setting. Such knowledge can provide hints on the factors to be prioritized in planning for improvement of neighbourhood satisfaction of residents in these cities. This paper thus examines the key predictors of neighbourhood satisfaction in a VI-SUE. Household heads (n = 289), cutting across the three identifiable types of neighbourhoods in Jos, Nigeria, expressed their level of satisfaction on a 71-item self-administered structured survey instrument. The principal component analysis with varimax rotation option explored 10 factors to represent the examined attributes of the neighbourhood environment. The third (final) in the sequence of hierarchical regression models estimated, indicates that none of the socio-economic and demographic attributes and dwelling attributes is significant in pre-dicting neighbourhood satisfaction in VISUE. Three factors: neighbourhood safety and stability, social relationships, and neighbourhood facilities and services, emerge as the key predictors of neighbourhood satisfaction. On the basis of these findings, these three attributes are required to be given precedence in any policy action aiming to improve residents’ satisfaction with their neighbourhoods in VI-SUE

Photocatalytic Degradation of Methylene Blue under UV Light Irradiation on Prepared Carbonaceous TiO

This study involves the investigation of altering the photocatalytic activity of TiO2 using composite materials. Three different forms of modified TiO2, namely, TiO2/activated carbon (AC), TiO2/carbon (C), and TiO2/PANi, were compared. The TiO2/carbon composite was obtained by pyrolysis of TiO2/PANi prepared by in situ polymerization method, while the TiO2/activated carbon (TiO2/AC) was obtained after treating TiO2/carbon with 1.0 M KOH solution, followed by calcination at a temperature of 450°C. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TG-DTA), Brunauer-Emmet-Teller (BET), and UV-Vis spectroscopy were used to characterize and evaluate the prepared samples. The specific surface area was determined to be in the following order: TiO2/AC > TiO2/C > TiO2/PANi > TiO2 (179 > 134 > 54 > 9 m2 g−1). The evaluation of photocatalytic performance for the degradation of methylene blue under UV light irradiation was also of the same order, with 98 > 84.7 > 69% conversion rate, which is likely to be attributed to the porosity and synergistic effect in the prepared samples

Breathing exercise for hypertensive patients: A scoping review

Background: Non-pharmacological management of hypertension includes weight loss, alcohol and sodium restriction, regular exercise, and relaxation. In people with overweight hypertension, systolic blood pressure (SBP) and diastolic blood pressure (DBP) can be decreased via exercise and weight loss together. Breathing exercises are one method of relaxing.Objectives: The aim of this scoping review is to map the information that is currently available about the advantages of breathing exercises in decreasing blood pressure in hypertension patients.Methods: This scoping review adheres to Arksey and O’Malley’s framework, which entails identifying review questions, seeking pertinent evidence, choosing pertinent studies, mapping data, and discussing, concluding, and reporting the findings. The PRISMA flowchart is used to show how the evidence search process works.Results: As a result, 339 articles in total were retrieved from the three databases. 20 papers total were included in this review after screening. In 14 of the 20 investigations, participants with stage 1 and stage 2 essential hypertension, two with pre-hypertension, and four with Isolated Systolic Hypertension (ISH) were studied. The respondents’ ages ranged from 18 to 75. The systolic blood pressure declined by 4–54.22 mmHg, while the diastolic blood pressure dropped by 3–17 mmHg.Conclusion: Slow breathing can be used as an alternate, non-pharmacological therapy for hypertension individuals to reduce blood pressure.Systematic Review Registration: (https://osf.io/ta9u6/)

Review of Polymer, Dye-Sensitized, and Hybrid Solar Cells

The combination of inorganic nanoparticles semiconductor, conjugated polymer, and dye-sensitized in a layer of solar cell is now recognized as potential application in developing flexible, large area, and low cost photovoltaic devices. Several conjugated low bandgap polymers, dyes, and underlayer materials based on the previous studies are quoted in this paper, which can provide guidelines in designing low cost photovoltaic solar cells. All of these materials are designed to help harvest more sunlight in a wider range of the solar spectrum besides enhancing the rate of charge transfer in a device structure. This review focuses on developing solid-state dye-synthesized, polymer, and hybrid solar cells

Utilization of natural dyes from Zingiber officinale leaves and Clitoria ternatea flowers to prepare new photosensitisers for dye-sensitised solar cells

Chlorophyll and ternatin were extracted from Zingiber officinale leaves and Clitoria ternatea flowers respectively. These natural dyes were applied as sensitisers in TiO2-based dye-sensitised solar cells (DSSCs). Among 10 different solvents, the ethanol extracts revealed the highest absorption spectra of natural dyes extracted from Z. officinale and C. ternatea. A major effect of temperature increase was the increased extraction yield. High chlorophyll and ternatin yields were obtained under extraction temperatures of 80 °C and 70 °C, respectively. A notable decrease in C. ternatea dye concentration at temperatures >70 °C was also observed. High dye concentrations were obtained using acidic extraction solutions, particularly those with a pH value of 4. Experimental results showed that the DSSC fabricated with chlorophyll extracted from Z. officinale leaves exhibited a conversion efficiency of 0.30%, open-circuit voltage (Voc) of 0.56 V, short-circuit current (Isc) of 0.8 mA/cm−2 and fill factor (FF) of 57.93%. The DSSC sensitized with ternatin from C. ternatea flowers displayed a conversion efficiency of 0.13%, Voc of 0.54 V, Isc of 0.3 mA/cm−2 and FF of 81.82%

Effects of deposition time on of cobalt sulfide thin film electrode formation

Cobalt sulfide counter electrodes (CE) were prepared using the electrodeposition and ionic exchange deposition method on the fluorine doped tin oxide (FTO). Time deposition effect of thin film were analyzed by using a field emission scanning X-ray diffraction (XRD), field emission electron microscope (FESEM), atomic force microscopic (AFM), and profilometry. The electrocatalytic activities of electrode were measured using cyclic voltammetry (CV) analysis. The growth of cobalt sulfide structure was confirmed by XRD. Therefore, the optimum deposition time of cobalt sulfide thin film electrode at 10 min was exhibiting the higher electrocatalytic activity with cathodic current and surface roughness of -3.36 mA.cm-2 and 34 nm, respectively