224 research outputs found
Abiotic Controls on Soil Enzyme Activity and Community Composition of Micro-eukaryotes: A Comparison of Arctic, Temperate and Tropical Peatlands
Tribological investigation of frictional behaviour of mild steel under canola bio-lubricant conditions
In this study, two stock engine oils were developed using different blends of a vegetable oil (canola oil), mixed with fully synthetic oil (0 %, 20 %, 40 %, 60 %, and 80 % of synthetic oil). The viscosity of the prepared blends was determined at different temperatures (20 ºC – 80 ºC). Tribological experiments were conducted, according to the conditions of the prepared lubricants, to investigate the influence of the newly developed oil on the frictional characteristics of mild steel material against stainless steel subjected to adhesive wear loading. Scanning electron microscopy was used to examine the worn surface of the mild steel. The results revealed that blending the canola oil with synthetic oil increases the viscosity of the lubricants. Moreover, the viscosity of the canola oil and its blends with synthetic oil is controlled by the environmental temperature since increasing the temperature reduces viscosity. The experimental results revealed that the frictional coefficient of the mild steel was dependent on the applied load and velocity rather than the sliding distance. In addition, pure canola oil as a lubricant was able to compete in performance with a blend of 80 % synthetic and 20 % canola oils
A Study on Consumer Preferences for E Shopping with reference to Bahraini Consumers
Technology based Internet has shortened the gap between continents, countries, cities, towns and villages and people. Different parts of the people have similar tastes, perceptions, styles and accessibility. Now Online shopping has opened the doors of globalization as it facilitate all the information about the product from anywhere around the world and it can be accessed 24/7. Therefore organizations have changed their selling and buying strategy. An even consumer preferences also has changed in terms of choices, quality, services, selling and buying. The main reason behind this is that, most of the electronic devices apps are well connected to the internet. Therefore, consumers are showing very enthusiastic behavior to buy and sell their chosen product. Keeping these benefits in their mind consumers are acting very smart and showing lots of interest to do online shopping, why because its saves time, easy payment and it will display many options to choose best of the best of his choice of product. The present study is to know which factors are influences Bahraini consumers to go for E shopping. The study further discloses that which professions are showing interest in E shopping in Bahrain. The Researchers dropped their suggestions for E tailors and consumers so that it can be implemented for further success. Key words: E shopping, consumers, payment mode, purchase mode
Effect of Aging Process in Different Solutions on Kenaf Fibre Structure and Its Interfacial Adhesion in Epoxy Composites
A Multi-Layer Approach For Detection Of Selective Forwarding Attacks In Wireless Sensor Networks
Wireless sensor networks (WSNs) are increasingly used due to their broad range of important applications in both military and civilian domains. Security is a major threat in WSNs. WSNs are prone to several types of security attacks. Sensor nodes have limited capacities and are deployed in dangerous locations; therefore, they are vulnerable to different types of attacks, including wormhole, sinkhole, and selective forwarding attacks. Security attacks are classified as data traffic and routing attacks. These security attacks could affect the most significant applications of WSNs, namely, military surveillance, traffic monitoring, and healthcare. Therefore, many approaches were suggested in literature to detect security attacks on the network layer in WSNs. The network layer is of paramount significance to the security of WSNs to prevent exploitation of their confidentiality, privacy, availability, integrity, and authenticity. Reliability, energy efficiency, and scalability are strong constraints on sensor nodes that affect the security of WSNs. Because sensor nodes have limited capabilities in most of these areas, selective forwarding attacks cannot be easily detected in networks. In this dissertation, an approach to selective forwarding detection (SFD) is suggested. The approach has three layers: MAC pool IDs, rule-based processing, and anomaly detection. It maintains the safety of data transmission between a source node and base station while detecting selective forwarding attacks. Furthermore, the approach is reliable, energy efficient, and scalable
The Experimental Investigation of The performance of Phosphor Coating
Different screen printing parameters have a distinct effect on the quality of coating that is created. This experimental work looked to measure these parameters. It is divided into two parts where the first part measured the surface wettability of various substrates Wettability measurement was performed through measuring the contact angle between the droplet and the substrate surface. Varying the UV exposure time by putting substrate in the UV ozone cleaner has a considerable effect on the wettability of the surface. Water was supplied to a PEDOT: PSS substrate via Fibro DAT 1100 which is attached to a camera and a computer for capturing and analyzing coatings for the spread of a water droplet on the substrate surface. From these analyses, the main aim is to measure the contact angle between the droplet and the substrate surface which indicates the surface wettability. Some factors may affect the wettability of the surface such as varying the UV time and varying the hold time. As a result, increasing these times will decrease the contact angle where a small contact angle indicates a favorable wettability. The second part measured the electrical resistance and transparency of the printed ink after various printing experiments such as implementing UV treatment, changing the ink and changing the mesh ruling. The Rheometer device was used to test the properties of the specimen. Where this device can be used to measure the properties of the specimen such as the shear modules, in this paper the plate was used to effect on the specimens, where different readings are recorded for these specimens. Also, 24 samples were prepared and the electrical resistance for these samples was measured in this paper. As a result, the electrical resistance for treated samples was greater than that for untreated samples; the electrical resistance of Elentan ink was greater than that for PEDOT at the same conditions. Changing the screen size from (61-64) to (40-100) increase the value of resistance at the same conditions. For the transparency measurements the Elentan ink had a higher transparency than PEDOT ink. The paper also carried out an analysis for the relation between the thickness of the phosphor layer and the lamp output, where the relation was inversely proportion
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Design procedure for brushless doubly-fed machine used as a limited speed-range pump drive
The continuing desire of industry to further improve process efficiency,
through tighter control and energy conservation, has prompted users to pay closer
attention to Adjustable Speed Drives (ASDs). The conventional ASDs consist of
induction or synchronous motors controlled by power electronic controllers through
the adjustment of supply frequency and line voltage. The drawback of these
conventional ASDs lies in the high cost of the power electronic controllers which
have the same rating as that of the machine itself.
The Brush less Doubly-Fed Machine (BDFM) ASD has proven, both
analytically and experimentally, to provide a cost effective and a wide range of
precise speed control. The experimental BDFM prototypes built to date were
designed and constructed individually based on designers' experience with self-cascaded
machines. The success with these prototypes has promoted the idea of
standardizing the design procedure for all future BDFMs. This thesis offers a
general design procedure for the BDFM, which can serve as a first step in
standardizing the manufacturing process of this machine. The procedure is
presented in the form of a demonstration, by applying it to the design of a 60-hp,
600 to 900 r/min, 460-volts BDFM pump drive to replace the currently utilized
conventional 60-hp wound rotor induction motor ASD. An ideal design, which
determines machine details such as physical dimensions, slot specifics and
conductor details based on conservative magnetic and electric loading assumptions,
is one form of the design procedure. The other form, the practical design, involves
utilizing a specified physical dimensions and slot details to determine the associated
conductors' details and to insure the compliance of machine loadings with up-to-date
industrial standards. In both procedures, the design will be made to satisfy, if
not to exceed, the existing conventional drive performance
Recent trends in biodiesel production from commonly used animal fats
Changes in climate due to the enormous amount of carbon dioxide emissions have really encouraged the development of energy sources that are renewable, sustainable, and eco-friendly. The development of alternative energy sources can also be attributed to the rapid decrease in resources of fossil energy. Biodiesel has gained significant interest in recent years due to its fossil fuel–like properties and sustainable and eco-friendly characteristics. However, most biodiesels are expensive because of the high cost of feedstock largely based on edible vegetable oil sources. The use of animal fats waste as cost effective feedstock in biodiesel production has gained considerable attention in recent years. Although, most studies regarding the use of animal wastes as feedstock in biodiesel production are still in the early stages, the advantages of this type of feedstock have been highlighted in the literature. However, most studies have not focus on the recent advances in the use of animal fats waste. The studies on the use of novel approach have been reported in isolation. Therefore, this current study attempts to highlight recent developments of the most commonly used animal fats waste in the production of biodiesel. In addition, emphasis was given to the most appropriate production technique, catalyst, energy requirement, and optimum reaction conditions
Melittin Exerts Beneficial Effects on Paraquat-Induced Lung Injuries in Mice by Modifying Oxidative Stress and Apoptosis
Melittin (MEL) is a 26-amino acid peptide with numerous biological activities. Paraquat (PQ) is one of the most widely used herbicides, although it is extremely toxic to humans. To date, PQ poisoning has no effective treatment, and therefore the current study aimed to assess for the first time the possible effects of MEL on PQ-induced lung injuries in mice. Mice received a single intraperitoneal (IP) injection of PQ (30 mg/kg), followed by IP treatment with MEL (0.1 and 0.5 mg/kg) twice per week for four consecutive weeks. Histological alterations, oxidative stress, and apoptosis in the lungs were studied. Hematoxylin and eosin (H&E) staining indicated that MEL markedly reduced lung injuries induced by PQ. Furthermore, treatment with MEL increased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity, and decreased malonaldehyde (MDA) and nitric oxide (NO) levels in lung tissue homogenates. Moreover, immunohistochemical staining showed that B-cell lymphoma-2 (Bcl-2) and survivin expressions were upregulated after MEL treatment, while Ki-67 expression was downregulated. The high dose of MEL was more effective than the low dose in all experiments. In summary, MEL efficiently reduced PQ-induced lung injuries in mice. Specific pharmacological examinations are required to determine the effectiveness of MEL in cases of human PQ poisoning
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