Optimal dynamic transport selection for wireless portable devices

Recent technological advances in mobile computing and wireless communication have made portable devices, such as PDA, laptops, and wireless modems to be very compact and affordable. On the other hand, wireless networks have gained such wide popularity that new network infrastructure is continually introduced. It is thus likely that many of the future portable devices will be equipped with multiple wireless modems such as Bluetooth and 802.11 WLAN, in order to increase device inter‐operability. The availability of multiple modems can leverage the performance of the communication traffic generated by the applications, for example Internet access. We envision a tool for managing the device connection through these modems. At the core of this tool is an optimization engine that splits packet traffic across a subset of the available transports so that user's performance metrics are maximized. This paper describes a mathematical model for such an optimization problem considering its applicability to small portable devices. Relevant quality of service (QoS) parameters such as bandwidth, average delay, and energy consumption are covered in the model. The mathematical formulation is validated using a simulated environment. The experimental results have demonstrated the effectiveness of our model and captured the inter‐relationship among the quality parameters. Copyright © 2006 John Wiley & Sons, Ltd.     

Uncertainty in a nested relational database model

Some database models have already been developed to deal with complex values but they have constrains that data stored is precise and queries are crisp. However, as many researchers have pointed out, there is a need to present, manipulate, and query complex and uncertain data of various non-traditional database applications such as oceanography, multimedia, meteorology, office automation systems, engineering designs, expert database systems and geographic information systems. In this paper, we present a logical database model, which is an extension of a nested relational data model (also known as an NF² data model), for representing and manipulating complex and uncertain data in databases. We also introduce a possible physical representation of such complex and uncertain values in databases and describe the query processing of the model that we discuss here.     

Investigation of the reflector temperatures of a space craft thermionic reactor

In a fast incore thermionic spacecraft reactor for nuclear propulsion, the temperature rise due to the neutron heating in the reflector control drums is investigated. The reactor is fuelled with (U-Ta)C, consisting of 80UC-20TaC with a sinter density of 80% and controlled with the help of rotating drums imbedded into the beryllium reflector. The control drums contain natural B₄C strips (with 20% ¹⁰B and 80% ¹¹B) and produce nuclear heat via neutron absorption in ¹⁰B. The neutronic analysis has been conducted in S₁₆-P₃ and S₈-P₃ approximation with the help of one- and two-dimensional neutron transport codes ANISN and DORT, respectively. Calculations are conducted for a reactor with a core radius of 22 cm and core height of 35 cm leading to 50 kW_el in power phase. Reflector drums with 100% natural B₄C in form of strips (drum diameter=13.5 cm, strip width=5 mm) at the outer periphery of the radial reflector of 16 cm thickness would make possible reactivity changes of Δk_eff,max=10.7% without a significant distortion of the fission power profile during all phases of the space mission. A reduction of the B₄C in the strips to 20 and 10% would still allow a reactivity change of Δk_eff,max=8.4 and 7.7%, respectively, amply sufficient for an effective control of a fast reactor during all phases of the space mission. By a nuclear thermal thrust around F=5000 N and a specific impulse of 670 s⁻¹ at an hydrogen exit temperature around 1900 K, the maximum temperature in the drums rises to 1023 K, with 100% natural B₄C content in the strips, far below the melting point of beryllium. The maximum drum temperature is depressed to 663 and 519 K, with 20 and 10% natural B₄C content in the strips, respectively.     

Effect of finite and different ground‐plane widths on quasistatic parameters of asymmetrical coplanar waveguides

Fast, accurate, and simple closed‐form expressions are presented for calculating the quasistatic TEM parameters of asymmetrical coplanar waveguides (ACPWs) with finite and different ground planes. The effect of the ground‐plane width and the asymmetry in the ground‐plane widths and in the spacings of ACPWs on the line parameters is investigated by using the formulas derived by conformal mapping techniques. Comparisons are also made between the present results and the results available in the literature for both the conventional coplanar waveguide (CPW) and the ACPW. The results in this article are in very good agreement with the results derived by the conformal mapping technique, by the variational formulation, and by the spectral‐domain method. It has been shown that the asymmetry of both ground planes and spacings leads to a significant change of the quasi‐TEM parameters with respect to cases of the finite and infinite ground planes. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 383–389, 2000.     

Finite rotations in dynamics of beams and implicit time-stepping schemes

We examine theoretical and computational aspects of three-dimensional finite rotations pertinent to the dynamics of beams. The model problem chosen for consideration is the Reissner beam theory capable of modelling finite strains and finite rotations in geometrically exact manner. Special emphasis is placed on clarifying the geometry aspects, finite rotation updates and the associated linearization procedure pertaining to different choices of rotation parameters. The latter is shown to play an important role in constructing the optimal implementation of a time-stepping scheme. © 1998 John Wiley & Sons, Ltd.     

Metabolic fingerprint of patients showing responsiveness to treatment of septic shock in intensive care unit

Magnetic Resonance Materials in Physics, Biology and Medicine - An early metabolic signature associated with the responsiveness to treatment can be useful in the better management of septic shock...     

Selection of Wind Turbine Systems for the Sultanate of Oman

The Sultanate of Oman has been dealing with a severe renewable energy issue for the past few decades, and the government has struggled to find a solution. In addition, Oman’s strategy for converting power generation to sources of renewable energy includes a goal of 60 percent of national energy demands being met by renewables by 2040, including solar and wind turbines. Furthermore, the use of small-scale energy from wind devices has been on the rise in recent years. This upward trend is attributed to advancements in wind turbine technology, which have lowered the cost of energy from wind. To calculate the internal and external factors that affect the small-scale energy of wind technologies, the study used a fuzzy analytical hierarchy process technique for order of preference by similarity to an ideal solution. As a result, in the decision model, four criteria, seventeen sub-criteria, and three resources of renewable energy were calculated as options from the viewpoint of the Sultanate of Oman. This research is based on an examination of statistics on energy produced by wind turbines at various locations in the Sultanate of Oman. Further, six distinct miniature wind turbines were investigated for four different locations. The outcomes of this study indicate that the tiny wind turbine has a lot of potential in the Sultanate of Oman for applications such as homes, schools, college campuses, irrigation, greenhouses, communities, and small businesses. The government should also use renewable energy resources to help with the renewable energy issue and make sure that the country has enough renewable energy for its long-term growth.     

Effects of repeated frying on physicochemical characteristics,oxidative stress,and free radical scavenging potential of canola oil and ghee

The repeated use of cooking oils and ghee for the deep frying of food materials may affect their nutritional quality. The present study evaluated the effect of repeated frying on the physicochemical characteristics and antiradical potential of canola oil and ghee. The oil and ghee were used for frying of fish and chicken for 2, 4, 6, 8, and 10 frying cycles followed by the analysis of physicochemical, oxidative stress, and antiradical parameters. Regression analysis of the data showed a frying cycle-dependent significant linear increase in saponification (R² = 0.9507–0.9748), peroxide and acid values (R² = 0.956–0.9915), and malondialdehyde (MDA) production (R² = 0.9058–0.9557) of canola oil and ghee subjected to fish and chicken frying but exponential increase in saponification value (R² = 0.9778) and MDA production (R² = 0.7407) of canola oil and ghee used for fish frying. The increase in the number of frying cycles linearly decreased the iodine value (R² = 0.9781–0.9924), and 1, 1-diphenyl-2-picrylhydrazyl, hydroxyl, and 2, 2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging potential (R² = 0.9089–0.9979) of canola oil and ghee. Repeated frying in cooking oil and ghee increases oxidative stress and decreases their physicochemical and antioxidant qualities. Canola oil was comparatively more oxidative resistant than canola ghee. The regression equations derived from regression analysis will guide researchers to conduct similar types of univariate studies.     

Nanoarchitectonics: Porous Hydrogel as Bio-sorbent for Effective Remediation of Hazardous Contaminants

The increasing use of heavy metals, dyes, and other metallic or chemical elements causes crucial environmental pollution. Sewage that contains these heavy metals and dyes is discharged into the atmosphere and goes directly into the food cycle, causing cancerous diseases and health deterioration in living organisms. The supreme concern of today’s research is to treat wastewater and effectively remove the hazardous dye molecules from aqueous media and other environmental matrices. Nowadays, technologies are applied to rectify organic and inorganic pollutants from sewage. Among them, adsorption is a fascinating way because it is environmentally friendly, feasible, and economical biomaterials. Chitosan (CS) as bio-sorbent is endowed with valuable characteristics, such as biodegradability, biocompatibility, high reactivity, low-cost, and functional groups (–OH and NH₂) on its surface. CS is used for many applications, either as a single component or composite form. The use of CS as bio-adsorbents is beneficial over regular adsorbents. Chitosan-based hydrogel is one of the very important bio-adsorbents. All these bio-adsorbents are highly used to eradicate toxic dyes, digest harmful industrial sewage, and eliminate pesticides, climatic hazardous waste, and contaminated materials from the environment.