Hydrogen Fire Detection System Features Sharp Discrimination

Hydrogen fire detection system discovers fires by detecting the flickering ultraviolet radiation emitted by the OH molecule, a short-lived intermediate combustion product found in hydrogen-air flames. In a space application, the system discriminates against false signals from sunlight and rocket engine exhaust plume radiation

Control of elasticity in cast elastomeric shock/vibration isolators

Elasticity is determined by isolators physical dimensions and by type of elastomer used. Once elastomer is selected and cast between two concentric tubes of device, isolator elasticity will remain fixed. Isolators having same dimensions can be built to different elasticity requirements using same elastomer

The Effect of Ice Formations on Propeller Performance

Measurements of propeller efficiency loss due to ice formation are supplemented by an analysis to establish the magnitude of efficiency losses to be anticipated during flight in icing conditions. The measurements were made during flight in natural icing conditions; whereas the analysis consisted of an investIgation of changes in blade-section aerodynamic characteristics caused by ice formation and the resulting propeller efficiency changes. Agreement in the order of magnitude of eff 1- ciency losses to be expected is obtained between measured and analytical results. The results indicate that, in general, efficiency losses can be expected to be less than 10 percent; whereas maximum losses, which will be encountered only rarely, may be as high as 15 or 20 percent. Reported. losses larger than 15 or 20 percent, based on reductions in airplane performance, probably are due to ice accretions on other parts of the airplane. Blade-element theory is used in the analytical treatment, and calculations are made to show the degree to which the aerodynamic characteristics of a blade section. must be altered to produce various propeller efficiency losses. The effects of ice accretions on airfoil-section characteristics at subcritical speeds and their influence on drag-divergence Mach number are examined, and. the attendant maximum efficiency losses are computed. The effect of kinetic heating on the radial extent of ice formation is considered, and its influence on required length of blade heating shoes is discussed. It is demonstrated how the efficiency loss resulting from an icing encounter is influenced by the decisions of the pilot in adjusting the engine and propeller controls

Accessing the Relative Sustainability of Point-of-Use Water Disinfection Technologies through Costs and Environmental Impacts

According to the World Health Organization, 785 million people lack access to basic drinking water facilities, and 144 million people rely on surface water which is prone to microbial contamination. Point-of-use (POU) water disinfection technologies can be adopted to help address these issues by treating water at the household level; however, navigating various POU disinfection technologies for a given water source or location can be difficult. While numerous conventional POU technologies exist (e.g., boiling water, POU chlorination), new emerging POU technologies (e.g., using novel materials or advanced processes) have been coined by developers to be lower cost with higher treatment capacity. It is unclear if these claims are substantiated and how novel technologies stack up against conventional ones in terms of cost and environmental impacts when considering a necessary level of disinfection for human health. This research compares POU technologies using quantitative sustainable design methods to assess four different POU treatment technologies. The technologies evaluated include chlorination using sodium hypochlorite, silver nanoparticle-enabled ceramic water filter, ultraviolet mercury lamps, and ultraviolet light-emitting diodes. This study leverages open-source Python packages to assess the relative sustainability using techno-economic analysis, life cycle assessment, and disinfection efficacy. Uncertainty is included in all input parameters, and sensitivity analysis (i.e., Spearman\u27s rank correlation) is used to identify which assumptions influence outcomes. The study assumes a household size of 6 people, and a lifecycle of 5 years. Escherichia coli is used as an indicator microbe in characteristic surface and ground waters. We set raw water types to capture the impact of water quality parameters (e.g., turbidity and total organic carbon) on sustainability. Per capita cost (USD∙cap-1∙yr-1) and global warming potential (kg CO2eq∙cap-1∙yr-1) are tracked as sustainability indicators. Study results can potentially inform decision makers, non-profit organizations, and future research on sustainable approaches to safe drinking water through POU technologies

Increasing security of supply by the use of a local power controller during large system disturbances

This paper describes intelligent ways in which distributed generation and local loads can be controlled during large system disturbances, using Local Power Controllers. When distributed generation is available, and a system disturbance is detected early enough, the generation can be dispatched, and its output power can be matched as closely as possible to local microgrid demand levels. Priority-based load shedding can be implemented to aid this process. In this state, the local microgrid supports the wider network by relieving the wider network of the micro-grid load. Should grid performance degrade further, the local microgrid can separate itself from the network and maintain power to the most important local loads, re-synchronising to the grid only after more normal performance is regained. Such an intelligent system would be a suitable for hospitals, data centres, or any other industrial facility where there are critical loads. The paper demonstrates the actions of such Local Power Controllers using laboratory experiments at the 10kVA scale

Prosthesis coupling

A coupling for use in an apparatus for connecting a prosthesis to the bone of a stump of an amputated limb is described which permits a bio-compatible carbon sleeve forming a part of the prosthesis connector to float so as to prevent disturbing the skin seal around the carbon sleeve. The coupling includes a flexible member interposed between a socket that is inserted within an intermedullary cavity of the bone and the sleeve. A lock pin is carried by the prosthesis and has a stem portion which is adapted to be coaxially disposed and slideably within the tubular female socket for securing the prosthesis to the stump. The skin around the percutaneous carbon sleeve is able to move as a result of the flexing coupling so as to reduce stresses caused by changes in the stump shape and/or movement between the bone and the flesh portion of the stump

Analysis of surface tris (2,3-dibromopropyl) phosphate on chlorobutyl rubber SCAPE suits

Tris (2,30-dibromopropyl) phosphate was used to confer flame retardant properties on butyl rubber formulations used in protective clothing such as the self-contained atmospheric protective ensembles (SCAPE suits) worn at Kennedy Space Center in support of Apollo, Skylab, and Apollo-Soyuz missions since 1966. Because tris (2,3-dibromopropyl) phosphate is mutagenic, surface concentrations of the compound in SCAPE suits were investigated as were as potential methods of removing or isolating it. Analytical procedures for determining surface concentrations of the tris compound on non-porous materials are described. Soap-and-water washing is the most efficient method of removing the compound from fabricated SCAPE suits and unused material

The Effects of Allium Sativum and Zingiber Officinale Extracts on Shigella Dysenteriae Isolated from Ready-To-Eat Fried Chicken Sold in Ihiala L.G.A, Anambra State

A number of reports have shown that foods vended on streets including fast foods meant for immediate consumption can have high incidence of pathogenic bacteria which can pose serious public health problems to the consumers and may result to different disease conditions. This study was undertaken to evaluate the effects of Allium sativum and Zingiber officinale seed extracts on Shigella dysenteriae isolated from ready-to-eat fried chicken sold in Ihiala L.G.A., Anambra State. A total of 21 samples were collected from street hawkers (9 samples) and fast foods (12 samples) joints and plated on Salmonella Shigella Agar (SSA) using pour plated method at appropriate growth conditions. The bacterial isolate was characterized and identified using colonial descriptions and biochemical reactions. The phytochemical constituents of the extracts of Allium sativum and Zingiber officinale were determined quantitatively using spectrophotometric method. Tube dilution method was used to determine the Minimal Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) using double-fold serial dilutions at concentrations 25mg/ml to 400mg/ml. The phytochemical analysis of Allium sativum and Zingiber officinale extracts revealed the presence of alkaloids, saponins, flavonoids, tannins, phenolics, steroids and cardiac glycosides. The ethanolic extracts of both plants showed more activity (9.00 mm, 10.70 mm) than their aqueous extracts (7.30 mm, 7.70 mm) and their activity differed significantly (p< 0.05) from that of the ciprofloxacin (21.30 mm). The MICs (200 mg/ml, 400 mg/ml; 200 mg/ml, 400 mg/ml) and MBCs (400 mg/ml, Nil; 400 mg/ml, Nil) values revealed the inhibitory activities of ethanolic and aqueous extracts of Allium sativum and Zingiber officinale and cidal activities of their ethanolic extracts. The study recommends personal and environmental hygiene as preventive measures against bacterial contamination of foods and suggests that Allium sativum and Zingiber officinale could be used as alternative therapy for diseases associated with Shigella dysenteriae