The availability of daylight from tropical skies—a case study of Malaysia

In Malaysia, no long-term daylight data are measured. It was only recently that the need to measure the availability of daylight became urgent when the importance of daylighting in buildings was rediscovered. The hourly daylight availability has been simulated for the Malaysian sky using daylight modelling techniques based on empirical and measured solar irradiation and cloud cover data. This paper presents the techniques involved in producing exterior illuminance data. These data were then compared with measured illuminance at Shah Alam and Bangi, Malaysia. The global illuminance levels are generally high, with values exceeding 80,000 lux at noon during the months when solar irradiation is highest. Even during the months when the ground receives less solar irradiation, the peak illuminance can reach 60,000 lux. Applications and uses of such data are in daylighting design, both for visual and thermal comfort, task illuminance and energy-conscious design of buildings. Recommendations are made at the end of the paper on the various climatic data that are required to be measured for overall daylighting design applications.     

Changes of the corneal endothelium after ultraviolet-B exposure in previously photokeratectomized eyes

The photorefractive effect of excimer lasers is based on an interaction between the 193-nm ultraviolet-C laser beam and the stromal chromophore molecules. Recently, in some patients an increase of subepithelial haze and a regression of refractive effect has been observed following suntanning (UV-B exposure). The aim of the study was to find out the possible endothelial damage caused by photoablation with increasing depth and the effect of subsequent UV-B exposure on previously photokeratactomized eyes. Altogether 12 chinchilla rabbits were treated. Four animals received a -5.0 D PRK; four animals a -15.0 D PRK and four animals a -30.0 D PRK treatment. The endothelial average number, size and variation were determined two weeks post-PRK. Three weeks following PRK, a half of the animals received a 1 J/cm2 ultraviolet-B radiation in a constant dermatological UV-chamber. The endothelial morphology was measured the same way with automated specular microscopy two weeks after UV-B irradiation. After PRK treatment there was no statistically demonstrable change in endothelial morphology. On the other hand, after UV-B radiation all eyes showed a decrease in endothelial number and an increase in size and variation. The ratio of hexagonality decreased, and endothelial rosette formation appeared. The early morphological changes resembled the physiological aging changes. Conditions (deep stromal photoablation, cumulative effect of suntanning or solarium treatments) may exaggerate the physiological aging processes leading to subsequent pleomorphism, polymegatism and cell loss. This may accelerate corneal dysfunction.     

Scientific Workflow Makespan Minimization in Edge Multiple Service Providers Environment

The edge computing model offers an ultimate platform to support scientific and real-time workflow-based applications over the edge of the network. However, scientific workflow scheduling and execution still facing challenges such as response time management and latency time. This leads to deal with the acquisition delay of servers, deployed at the edge of a network and reduces the overall completion time of workflow. Previous studies show that existing scheduling methods consider the static performance of the server and ignore the impact of resource acquisition delay when scheduling workflow tasks. Our proposed method presented a meta-heuristic algorithm to schedule the scientific workflow and minimize the overall completion time by properly managing the acquisition and transmission delays. We carry out extensive experiments and evaluations based on commercial clouds and various scientific workflow templates. The proposed method has approximately 7.7% better performance than the baseline algorithms, particularly in overall deadline constraint that gives a success rate.

     

Eco‐friendly synthesis of silver nanoparticles and its larvicidal property against fourth instar larvae of Aedes aegypti

In this study, larvicidal activity of silver nanoparticles (AgNPs) synthesised using apple extract against fourth instar larvae of Aedes aegypti was determined. As a result, the AgNPs showed moderate larvicidal effects against Ae. aegypti larvae (LC₅₀  = 15.76 ppm and LC₉₀  = 27.7 ppm). In addition, comparison of larvicidal activity performance of AgNPs at high concentration prepared using two different methods showed that Ae. aegypti larvae was fully eliminated within the duration of 2.5 h. From X‐ray diffraction, the AgNP crystallites were found to exhibit face centred cubic structure. The average size of these AgNPs as estimated by particle size distribution was in the range of 50–120 nm. The absorption maxima of the synthesised Ag showed characteristic Ag surface plasmon resonance peak. This green synthesis provides an economic, eco‐friendly and clean synthesis route to Ag.Inspec keywords: silver, nanofabrication, X‐ray diffraction, zoology, particle size, nanoparticles, biomedical materials, nanomedicineOther keywords: time 2.5 h, size 50 nm to 120 nm, silver nanoparticle, larvicidal property, instar larvae, Aedes aegypti, larvicidal effect, larvicidal activity performance, X‐ray diffraction, nanoparticle particle size distribution, absorption maxima, silver surface plasmon resonance peak     

国内首艘溢油应急清污船

国内首艘配有内置式收油机的专业溢油应急清污船，通过了有关部门审查，由长江船舶设计院进行设计，预计2008年可投入使用。     

Characterization of Clay Particle Surfaces for Contaminant Sorption in Soil Barriers Using Flow Microcalorimetry

Clays such as kaolinite and bentonite are widely used in various industries as sorbents. The sorptive characteristics of clays are exploited when they are used in contaminant barrier systems. To use clays effectively, their surface characteristics need to be known; especially, when they are used for contaminant sorption. Available surface area of clay minerals and the characteristics that depend on it are very sensitive to environmental changes such as those that can be induced by changes in the composition of pore fluid. Flow microcalorimetry with a down-stream concentration was used to determine the heats and amounts of adsorption of acids and bases on the clays. Test results presented herein revealed that both kaolinite and bentonite exhibit significantly different adsorption isotherms and heat of wetting under high pH and low pH conditions. Kaolinite has the capacity to adsorb both acidic and basic molecules almost equally. However, it has a tendency to adsorb more base than acid because of its stronger complexation capacity with acids than with bases. On the other hand, bentonite has a tendency to adsorb more acidic than basic molecules per gram. These results also indicate that both kaolinite and bentonite have different heats of wetting characteristics. As the concentrations of the acids and bases increase, the heat of wetting of kaolinite decreases while that of bentonite increases.     

Effects of feeding bentonite clay upon ochratoxin A–induced immunosuppression in broiler chicks

A presence of mycotoxins in feed is one of the most alarming issues in the poultry feed industry. Ochratoxins, produced by several Aspergillus and Penicillium species, are important mycotoxin regarding the health status of poultry birds. Ochratoxins are further classified into to several subtypes (A, B, C, etc) depending on their chemical structures, but ochratoxin A (OTA) is considered the most important and toxic. Bentonite clay, belonging to phyllosilicates and formed from weathering of volcanic ashes, has adsorbent ability for several mycotoxins. The present study was designed to study the effects of bentonite clay upon OTA-induced immunosuppression in broiler chicks. For this, 480 day-old broiler chicks were procured from a local hatchery and then different combinations of OTA (0.15, 0.3, or 1.0 mg/kg) and bentonite clay (5, 10, and 20 g/kg) were incorporated into their feed. At 13, 30, and 42 days of age, parameters such as antibody responses to sheep red blood cells, in situ lymphoproliferative responses to mitogen (PHA-P), and in situ phagocytic activity (i.e., via carbon clearance) were determined respectively. The results indicated there was a significant reduction of total antibody and immunoglobulin titres, lymphoproliferative responses, and phagocytic potential in OTA-treated birds, suggesting clear immunosuppression by OTA in birds in a dose-dependent manner. These results were also significantly lower in all combination groups (OTA with bentonite clay), suggesting few to no effects of feeding bentonite clay upon OTA- induced alterations in different immune parameters.