Characterization of a short microchannel device for surface cooling

The development of microchannel devices is expanded widely due to the demand for small scale electronic devices. In order to increase the capability of the electronic devices, high heat transfer performance with low energy consumption cooler is required. This study is focusing on the characterization of new short microchannel for surface cooling purposes with the channel dimension of 800 μm wide, 200 μm length, 100 μm depth and total area of one cm2. Deionized water is used as the transport medium. A map of microchannel characteristics is plotted in term of average thermal resistance, pumping power, power supplied and mass flow rate of the fluid. From this mapping, it is shown that the thermal resistance decreased as the pumping power decreased. The results also show that the heat flux has not affected the value of pumping power. The different for each heat flux value is ranged between 3 to 4 %. The mapping presented in this study provides potential characteristics information and conditions to apply this particular microchannel for surface cooling

Pre-treatment of laundry greywater by steel slag for safe disposal

Direct discharge of laundry greywater without any water pre-treatment in the drainage system has become a common practice in Malaysia. The study aimed to utilise steel slag as an adsorbent material for commercial laundry shop runoff (CLSR) to reduce chemical oxygen demand (COD) and total phosphorus (TP). Optimisation of the pollutants removal efficiency in CSLR by steel slag used Response Surface Methodology (RSM) using independent variables; different percentages of CLSR with tap water and contact time. The highest removal efficiency obtained for COD was 54.49% at 100% CLSR with tap water and 60 minutes of contact time. TP removal efficiency was 45.45% at 10% CLSR with tap water and 90 minutes of contact time. Thus, steel slag can increase the pH value, reducing the COD and TP values from CLSR in a short period. Hence, steel slag has the potential to be included in the “pre-treatment” system for CLSR based on its performance at COD and TP removal efficiency. From RSM, the model F�value and P-value for COD and TP were 5.89 and 10.62, 0.0166 and 0.0036, respectively. These values validated that the model was significant. Therefore, the study can contribute to the safe disposal of untreated laundry greywater to minimise environmental degradation

Fabrication, characterization and degradation of electrospun poly(?-caprolactone) infused with selenium nanoparticles

Polycaprolactone (pcl) is widely used in the fabrication of nanofibers through electrospinning technique. Pcl is a biodegradable material that is economical, simple and can be scaled up for industrial production. In this study, pcl was infused with selenium nanoparticles (senps) via electrospinning to fabricate pcl-senps nanofiber. Field emission scanning electron microscopy (fesem) images of the samples revealed ‘aligned fibers’ was successfully fabricated with a diameter size of less than 350 nm and an average diameter of 185 nm. The presence of se in the nanofiber was confirmed by energy dispersive x-ray analysis (edx) and raman spectra. Based on the x-ray diffraction (xrd) pattern, the structure of pcl did not change and remains in the pcl-senps nanofibers. The functional groups of pcl, as indicated by infrared (ir) spectra remained the same after senps infusion. These results demonstrated that the physical and chemical properties of pcl nanofibers were not affected by the infusion of senps. In addition, the hydrophobicity of the pcl decreased slightly in the presence of senps. The first month after degradation, disorganized and fibrous fibers of pcl-senps nanofiber were observed followed by the formation of large fiber clumps as degradation time increased. An agglomerated senps made pcl-senps nanofiber pores looser and easier to be hydrolyzed after 4 months of degradation. The sticky surface of pcl-senps nanofiber shows acceleration in the hydrolysis process after 24th weeks of degradation. The presence of senps enhanced the degradation behavior as well as reducing the degradation time to break into pieces, starting after 6 months of degradation. The ‘aligned’ pcl-senps nanofiber, which can mimic the natural tissue extracellular matrix (ecm) morphology, can potentially be used in biomedical applications such as tissue engineering, wound dressing, biomedicine, sensor and filtration application

Numerical evaluation of thermo-hydraulic performance in fin-and-tube compact heat exchangers with different tube cross-sections

This study examined numericallythe Thermal-hydrodynamic properties of airflow in the fin-and-tube compact heat exchangers (FTCHEs) with considering different shapes of tubes in lowReynoldsnumbers. The influence of applying flat, oval and circular tube adjustments on the thermal and hydraulic characteristics of air flow were analyzed on the in-line tube arrangements. Establishing standard conditions, the study compared different geometries based on circular tubes of 10.459 mm diameter tubes with 25.4 mm longitudinal pitches and 25.4 mm transverse pitches. The other geometries of tubes were assumed in a stable and constant state preparing the same heat transfer surface area per unit volume as that of the nominal case. The results showed that the FTCHE with flat tubes gives the best area goodness factor (j/f) with in a certainrange of Reynoldsnumbers. In addition, FTCHE with flat tubes shown the best thermo-hydraulic performance and a significant augmentation of up to 10.83% and 35.63% in the average area goodness factor achieved accompanied by a decrease in the average friction factor of 17.02% and 43.41% in the flat tube case compared to the oval and circle tube shapes, respectively. It is concluded that the average area goodness factorfor the oval tube is about 25.04% higher than that of the circular tube, while the average friction factor for the oval tube is about 26.9% lower than that of the circular tube. This means that the flat tube has a better-combined thermal-hydraulic performance than the oval and circle tube

A review of Websites and Mobile Applications for People with Autism Spectrum Disorders: Towards Shared Guidelines

Many studies show the effective positive impact of using computer technologies to support the lives of users with autism spectrum disorders (ASD), for simplifying interaction with other people, for organising daily activities, for improving relation with family and friends. Despite that, only a restricted part of the current websites is accessible for people with ASD. In this paper, we discuss a set of guidelines that should be followed by designers while developing websites or mobile applications for users with ASD. We review many of the existing websites and applications in order to check which comply with all, or parts of these guidelines. We finally highlight current common limitations and address new challenging research directions. \ua9 ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2017

Influence of modified air on combustion characteristics in meso-scale vortex combustor

The need to supply power for miniaturized mechanical devices opens exciting new opportunities for combustion, especially in the field of micro-power generation. Because of the need for power supply devices with high-specific energy (small-size, low weight, long duration) and power. Meso/micro scale combustion has been considered as a potential solution for many small-volumes and energy demanding systems, such as power supplies for portable device. In this study the structure of turbulent diffusion flames in a meso scale combustor with different oxygen concentration has been investigated using a new design of vortex combustor. Methane gas was used as a fuel. Numerical investigations have been performed on the temperature distribution, swirl number, heat loss, and emitter efficiency in vortex combustion. The results have been obtained for various O2 concentrations in the air as oxidizer. The results shows that thermal flame behaves depend strongly on the oxygen content in the oxidizer. When the oxygen concentration increases from 15% to 30%, the flame temperature of the meso-combustion rises in all cases. Emitter efficiency is very high in the meso-combustor with high O2 concentration in oxidizer

Comprehensive review on high hydrogen permselectivity of palladium based membranes: part ii -hydrogen permeation flux under concentration polarisation influence

This article completes the presentation of various techniques reducing concentration polarisation in palladium based membranes for supplying ultrahigh purity hydrogen to a polymer electrolyte fuel cell (PEFC), such as the implementation of baffles and the use of microchannel configuration. The present paper also reviews and reports the current methods for estimating hydrogen permeation flux under concentration polarisation influence, which will be a useful guide for academics and industrial practitioners

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

Background: The EMPA KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population. Methods: EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110. Findings: Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5–2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62–0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16–1·59), representing a 50% (42–58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1). Interpretation: In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease. Funding: Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council