19672 research outputs found
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Modified photo-current response of an organic photodiode by using V2O5 in both hole and electron transport layers
No full textIn this study, we demonstrate a novel approach to use vanadium pentaoxide (V2O5) as a single material that can simultaneously function as both electron blocking and transport layers (EBLs and ETLs) in an organic photo-detector (OPD). Composite of V2O5 and PEDOT:PSS was introduced as hole transport layer (HTL) whereas, single V2O5 film was utilised as an ETL. The resultant device had the ITO/PEDOT:PSS+V2O5/PCDTBT:PC71BM/ V2O5/Al architecture and exhibited a new range of photo-current as well as showed an enhanced photo-response. For comparison, we also fabricated devices with ITO/PCDTBT:PC71BM/Al, ITO/PEDOT:PSS/PCDTBT:PC71BM/Al and ITO/PEDOT:PSS+V2O5/PCDTBT:PC71BM/Al architectures. The device with ITO/PCDTBT:PC71BM/Al architecture showed a photo-response in the range of ∼2.3 (OFF) to ∼6.7 mA/cm2 (ON) which increased to almost double after the inclusion of PEDOT:PSS as an HTL and reached to ∼2.3 and ∼12.6 mA/cm2 in OFF and ON states, respectively. In the third variant of devices with the addition of V2O5 in PEDOT:PSS to form a composite HTL, the photo-response narrowed down to ∼5.4 (OFF) and ∼12.6 mA/cm2 (ON). Lastly, the new approach with the addition of an ultrathin V2O5 layer as an ETL along with composite HTL demonstrated a new range of photo-current with enhanced photo-response in the range of 13.2 mA/cm2 (OFF) and ∼20.7 mA/cm2 (ON). The findings of the current work suggest that addition of V2O5 based ETL has tuned both photo-current and response range of the OPDs. In addition, inclusion of V2O5 into the PEDOT:PSS could effectively block the electrons due to its large band-gap
Do religiosity, gender and educational background influence zakat compliance? The case of Malaysia
No full textPurpose: The purpose of this paper is to examine the influence of religiosity, gender and Islamic educational background of Muslims on zakat compliance. It also aims to identify which dimensions of religiosity are significantly related to zakat compliance. Design/methodology/approach: The study uses a self-administered questionnaire that was distributed to working Muslims individuals in Klang Valley, Malaysia. Analysis of the data was based on 690 usable questionnaires. Findings: The findings show that religiosity had a significant influence on zakat compliance and three dimensions of religiosity, namely obligation, virtues and vices, and optional ritual, were significantly related to zakat compliance. Gender was also significantly related to zakat compliance, but in a negative direction, suggesting that Muslim working females are less compliant to zakat obligations compared to their male counterparts. It is found that formal Islamic educational background had no significant influence on zakat compliance. Practical implications: Given the importance of zakat collection to the growth of the economy and society, the findings of this paper might provide some insights to Muslim-majority countries and zakat institutions which areas require more attention to encourage zakat payment among Muslims. Originality/value: Compared to prior zakat studies, the findings of this study were derived from a larger sample size of Muslim working respondents. Furthermore, this study also identifies which dimensions of religiosity are significantly related to zakat compliance. Hence this study enriches the scarce literature on zakat and religiosity
A new approach to evaluate the impact of thermophysical properties of nanofluids on heat transfer and pressure drop
No full textIn this paper, an experimental and numerical study was conducted to evaluate the impacts of momentum and thermal diffusivity comparing to the thermal conductivity of various types of nanofluids on turbulent forced convection heat transfer. 1%, 2%, and 3% volumetric concentrations of different nanofluids such as Al2O3-DW, SiO2-DW, and Cu-DW were considered in this study and their properties were evaluated numerically at the flow inlet temperature of 30 °C. The experimental works were conducted with distilled water as a working fluid to validate the 2-D numerical model. A two-dimensional domain was constructed using ANSYS-Fluent package, and the standard k–ε turbulence model was employed to solve the continuity, momentum, and energy equations. The flow was maintained in the Reynolds range between 6000 and 12,000, and the data obtained experimentally were validated by results from empirical correlations. The numerical solutions for the average Nusselt number and pressure drop presents a good agreement with the experimental results as the average error was less than 5% for both the cases of heat transfer and pressure loss data. The results showed that Al2O3-DW nanofluid has the best enhancement in convection heat transfer coefficient compared with the DW and other nanofluids of the same concentration while Cu-DW nanofluids shown the lowest enhancement though it shown the highest value of thermal conductivity. Also, the results showed that the product of kinematic and dynamic viscosities had the greatest effect on pressure drop in the fluid domain
Acute and 28-day sub-acute intravenous toxicity studies of 1’-S-1′-acetoxychavicol acetate in rats
No full text1′-S-1′-acetoxychavicol acetate (ACA) has been previously reported to reduce tumor volume in nude mice, at an effective dose of 1.56 mg/kg body weight. However, the detailed toxicological profile for ACA has not yet been performed. Herein, we investigated the toxicity of intravenous administration of ACA in male and female Sprague-Dawley rats, both acutely (with single doses of 2.00, 4.00 and 6.66 mg/kg body weight, for 14 days), and sub-acutely (with weekly injections of 0.66, 1.33, and 2.22 mg/kg, for 28 days). In both toxicity studies, treatment with ACA did not affect behavior, food/water intake or body weight, nor did it induce any changes in clinically relevant hematological and biochemical parameters or mortality, suggesting that the LD 50 of ACA was higher than 6.66 mg/kg body weight, regardless of sex. Sub-acutely, there was however, mild focal inflammation of kidneys and lobular hepatitis, but these were not associated with significant functional adverse effects. Therefore, the no-observed-adverse-effect level (NOAEL) for intravenous administration of ACA in the present 28-day sub-acute study was 2.22 mg/kg body weight, in both male and female rats. These findings provide useful information regarding the safety of ACA use in a healthy, non-tumor-bearing rat model
Anthropometric measurements among four Asian countries in designing sitting and standing workstations
No full textAn anthropometric database for sitting and standing dimensions for Malaysian operators was developed based on the measurements from 146 male and 168 female participants (18–45 years old). The anthropometric data were subsequently compared to those from three selected Asian countries, focussing on the sitting and standing posture dimensions. Thirty-six anthropometric dimensions were selected for comparison based on common availability among the four countries. The results indicated that the Indonesians were the tallest (male: 172 cm, female: 159 cm) among the four countries, whereas the Filipinos were the shortest for both male and female (male: 167 cm, female: 153.9 cm). Filipinos and Malaysian data were almost similar and appear to have the smallest values for eye height (male: 155 cm, female: 143 cm) and elbow height (male: 104 cm, female: 96 cm). The knowledge of variations in the population is useful in designing sound workstations and facilities for the betterment of the industrial environment
Effect of compatibiliser on the properties of polypropylene/glass fibre/nanoclay composites
No full textGlass fibre (GF), nanoclay (NC) and hybrid composites compatibilised with maleic anhydride polypropylene (MAPP) were prepared by extrusion and injection moulding. The fourier transform infra-red spectra revealed the characteristic absorption peaks of MAPP in the compatibilised GF and NC composites. A decrement in the peak intensity of X-ray diffraction patterns of NC composite was obtained as the MAPP content increased indicating a partial exfoliation of NC. The thermogravimetric analysis showed that the incorporation of MAPP into hybrid composites reduced the thermal stability of the material. The dynamic mechanical analysis showed an increase in the storage modulus in the hybrid composites with lower content of MAPP due to the enhancement in the interfacial adhesion between the GF, NC and PP matrix
A New Black Fly Species of the Simulium (Gomphostilbia) duolongum Subgroup (Diptera: Simuliidae) from Vietnam, and Molecular Comparisons with Related Species Using the COI Barcoding Gene
No full textSimulium (Gomphostilbia) yvonneae sp. nov. is described based on adults, pupae, and mature larvae from Vietnam. This new species belongs to the Simulium duolongum subgroup in the S. batoense species-group of the subgenus Gomphostilbia Enderlein. It is distinguished by having a relatively larger number of male upper-eye facets in 16 vertical columns and 16 horizontal rows and a pupal gill with eight filaments arranged as 3+(1+2)+2 from dorsal to ventral, of which two filaments of the ventral pair are 1.8 times as long as the longest filament of the middle and dorsal triplets. Morphological comparisons are made to distinguish this new species from all 22 related species. The genetic distinctiveness of this new species in the S. duolongum subgroup is also presented based on the DNA barcoding COI gene. © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved
Comparing retainers constructed on conventional stone models and on 3D printed models: a randomized crossover clinical study
No full textObjectives: The aim of this study was to compare vacuum-formed thermoplastic retainers (VFRs) constructed on stone models (VFR-CV) and those constructed on three-dimensional (3D) printed models (VFR-3D) based on patients’ perspective and post-treatment stability. Study design: The research was designed as a crossover, randomized control trial. Materials and methods: Subjects comprised patients receiving fixed appliances at a teaching institution and indicated for VFRs. Post-treatment stone models were scanned with a structured-light scanner. A fused deposition modelling machine was used to construct acrylonitrile-butadiene-styrene (ABS)-based replicas from the 3D scanned images. VFRs were fabricated on the original stone and printed models. Analysis comprised independent t-tests and repeated measures analysis of variance. Randomization: Subjects were allocated to two groups using Latin squares methods and simple randomization. A week after debond, subjects received either VFR-CV first (group A) or VFR-3D first (group B) for 3 months, then the interventions were crossed over for another 3 months. Blinding: In this single-blinded study, subjects were assigned a blinding code for data entry; data were analysed by a third party. Outcome measures: The primary outcome measured was oral health-related quality of life (OHRQoL) based on Oral Health Impact Profile-14 (OHIP-14). Secondary outcome was post-treatment stability measured using Little’s Irregularity Index (LII). Results: A total of 30 subjects (15 in each group) were recruited but 3 dropped out. Analysis included 13 subjects from group A and 14 subjects from group B. Group A showed an increase in LII (P < 0.05) after wearing VFR-CV and VFR-3D, whereas group B had no significant increase in LII after wearing both VFRs. Both groups reported significant improvement in OHRQoL after the first intervention but no significant differences after the second intervention. LII changes and OHIP-14 scores at T2 and T3 between groups, and overall between the retainers were not significantly different. No harm was reported during the study. Conclusion: VFRs made on ABS-based 3D printed models showed no differences in terms of patients’ OHRQoL and stability compared with conventionally made retainers. © The Author(s) 2018. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved
Implementation of phase controlled impact device for enhancement of frequency response function in operational modal testing
No full textThis paper studies how to enhance frequency response function (FRF) estimation in the presence of harmonic disturbances during operational modal testing. A novel technique which utilizes impact-synchronous time averaging (ISTA) called impact-synchronous modal analysis (ISMA) was introduced where modal analysis can be performed in the presence of ambient forces. The phase angle information of the harmonic signal at the impact events is shown to be a key factor in enhancing the effectiveness of this technique. However, lack of knowledge and control of impact with respect to the phase angle of the disturbances using conventional impact hammer in ISMA has limited the effectiveness and practicality of this novel technique. A portable and automated phase controlled impact device is introduced in the effort to eliminate non-synchronous components with minimal possible impacts applied. This device makes use of the feeding phase angle information of responses from the cyclic load back to the device and imparts the impact at the correct time/phase which is always non-synchronous with respect to the phase of response from cyclic load. A reduced number of averages thereby expedite the overall modal testing procedure, an improved of FRF estimation and a good correlation of modal extraction data with benchmark data shown in this study has highlighted the advantages of ISTA using the proposed device
Ancient schwannoma of cervical sympathetic chain masquerading as carotid body tumour
No full textSchwannoma of cervical sympathetic chain is a rare cause of neck swelling. We report a 73- year-old male presented with anterior neck triangle swelling mimicking a carotid body tumour. Surgical excision was done, and the histopathological examination reported as ancient schwannoma. We would like to discuss the important differential diagnoses and highlight the possibility of an ancient schwannoma of cervical sympathetic chain masquerading as carotid body tumour. Also, to emphasise the importance of imaging for pre-operative planning and counselling