Moisture and heat transfer in hybrid weft knitted fabric with artificial intelligence

One of the most important properties of clothes is their ability to help the body's thermal system to keep the body temperature in its natural range, even if the environmental conditions or physical activities are outside the body's ideal range. Perspiring is one of the most important effects of physical activities in warm weather for shedding the body's excessive heat. Therefore, the basic requirement of a fabric worn next to the skin is to transfer this moisture to the atmosphere to reach comfort through the avoidance of a feeling of wetness and clamminess and also through the generation of a situation for the best surface evaporation of moisture. The main goal of this study was to achieve a kind of fabric that guarantees comfort for the body by good heat and moisture transport. To achieve this goal, a group of double‐surface fabrics containing hydrophilic and hydrophobe fibers were knitted, and their simultaneous heat and moisture transport was evaluated with the help of a perspiration‐simulation machine; the results were analyzed as transfer process plots. Also, the transmission of heat and moisture was evaluated for all of the samples by differential modeling as an artificial neural network. Effective parameters on heat and moisture transfer were taken into consideration with modeling and statistical methods. The results were analyzed to find a suitable fabric with optimum comfort. The final results showed that a fabric made of micropolyester filaments and cotton yarns on the bottom and top surfaces, respectively, had the best heat and moisture transfer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Leakage of Metallic Ball Seat Valves with Anisotropic Surfaces

Metallic ball seat valves are an essential component of many hydraulic systems. They are used for many different purposes such as pressure relief valves or check valves. Despite their universal usage, their sealing mechanism is not yet fully understood. In previous works, a successful method for the simulation of the fluid leakage of metallic ball seat valves has been developed and confirmed experimentally. The method is based on Persson's contact mechanics theory, which is based on surface roughness power spectrum C(q). This theory takes a wide range of roughness values at different length scales into account. The previous method has been restricted to isotropic surfaces, but most surfaces of practical interest are highly anisotropic. A method for the calculation of pressure flow factors using Persson's method is presented. Based on these, a model for the leakage calculation can be developed. The simulation results are validated using an experiment.     

Multi-Path Reasoning in a Database

Rules have been used in a database context for several purposes:deductive database queries, active database triggers, and productionsystem programs. Exploring the search space for non-deterministicrule programs, however, has generally been available only in largemonolithic systems intended for artificial intelligence applications.The goal of this research is to provide multi-path reasoning fornon-deterministic rule programs in a database environment. Themotivation for this work includes the increasing use ofdatabase-style triggers to assist data-intensive applications, e.g.,the human genome project and the Intelligent Integration ofInformation (I ³) Program.A non-deterministic rule program is one where there is more than oneterminal state. Such programs are generally not consideredappropriate for database queries where the focus is on rules programsor techniques that guarantee a unique fixed point. Butnon-deterministic programs are commonly used for various heuristicsearch problems such as the traveling salesperson problem. With anon-deterministic program, it is particularly important to beflexible about the order in which the search space is exploredbecause exhaustive search is generally not feasible. Thecontributions of this research are: the representation of themulti-path search tree within a database and the ability for theproblem solver to control the search process for a non-deterministicrule program.     

Energy Detector in Ultra Wideband Systems Using Phase Compensation Technique

Energy detectors have the advantage of simple structure and inexpensive price. Due to the low signal to noise ratio (SNR) of the received signal in ultra-wideBand (UWB) system, these desirable advantages can be achieved at the expense of non-trivial performance degradation. This paper presents a phase compensation (PC) technique to improve the performance of energy detector in UWB systems. In PC-UWB, the frequency dependent phase of the system response at the transmitter is extracted and its opposite spectral phase is used as prefilter. Because of Low complexity, cost and energy consumption of energy detectors, PC techniques has extensive potential for future of UWB communication systems. Measurement results show that the use of PC-UWB leads to signal power concentration at the receiver, which reduces the number of RAKE fingers required in coherent detection as well as achieves a higher data rate with less intersymbol interference. However time reversal UWB can achieve secure data transmission, but its performance is worse than PC-UWB. Simulation results show that phase compensation reduces the inter symbol interference impacts. Therefore it is possible to use a simple receiver with insignificant performance degradation. It is also shown that PC-UWB considerably outperforms TR-UWB and has satisfying performance in SNR greater than 13 dB.     

Effect of Channel Estimation Error on Time Reversal UWB Communication System

In this paper, effects of channel estimation error on time reversal (TR) UWB systems are investigated. In time reversal, a signal is prefiltered by using a time reversed complex conjugate of the channel impulse response as a transmitter prefilter. To investigate the effect of channel estimation error, an error function is added to TR-UWB prefilter. Analytical and simulation results show that channel estimation error degrade the performance. The signal-to-interference plus noise ratio decreases with increasing error variance. It is shown that the channel performance is degraded about 0.5 dB in CM1 and 1.3 dB in CM4 channel.     

Stability and a control strategy of a multilink musculoskeletalmodel with applications in FES

Introduces a relegated control strategy for point-to-point movement of musculoskeletal systems driven by redundant actuators. The actuator system is partitioned to two functional groupings referred to as gravity compensators and movement generators. Unlike dynamic optimization methods, relegation of control enables real-time computation of control signals to the muscle actuators. It is shown that this strategy significantly reduces the degree of coactivation needed to stabilize the movement. The real-time nature of this strategy coupled with reduced coactivation makes the proposed strategy amenable for multichannel control of paraplegics through functional electrical stimulation. Simulations of a three-link sagittal system are conducted to test the algorithm for a bowing movement     

Design of a lightweight and anonymous authenticated key agreement protocol for wireless body area networks

Wireless body area networks (WBANs) are a network designed to gather critical information about the physical conditions of patients and to exchange this information. WBANs are prone to attacks, more than other networks, because of their mobility and the public channel they use. Therefore, mutual authentication and privacy protection are critical for WBANs to prevent attackers from accessing confidential information of patients and executing undetectable physical attacks. In addition, in the authentication and key agreement process, messages should be transferred anonymously such that they are not linkable. In this paper, we first indicate that one of the most recently introduced authentication protocol is vulnerable to the wrong session key agreement attack and desynchronization attack. Second, we propose a lightweight authentication and key agreement protocol, which can withstand the well‐known attacks and provide the anonymity feature. Eventually, we analyze the security of our proposed protocol using both Automated Validation of Internet Security Protocols and Applications (AVISPA) and random oracle model and compare its performance with the related works. The results demonstrate the superiority of our proposed protocol in comparison with the other protocols.     

Electrospun polyvinylidene pyrolidone/gelatin membrane impregnated with silver sulfadiazine as wound dressing for burn treatment

Nanofibrous membranes used for burn treatment have become widely popular due to their large surface area and high porous structure. In this study, electrospinning was used to fabricate a blended nanofibrous membrane of polyvinylidene pyrolidone (PVP) and gelatin, to use as wound dressing. The physical and mechanical properties of this novel membrane were investigated using SEM, FTIR and tensile tests. Results showed that poor mechanical properties of gelatin, which are preferred in medical applications for curing burns as they allow for antigen activity and skin repair, can be enhanced by adding PVP in the solution. Silver sulfadiazine (AgSD), an antibacterial agent, was also impregnated into the PVP/gelatin nanofibrous structure during electrospinning. The membrane thus fabricated showed antibacterial activities against both the Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. AgSD release behaviour of fabricated samples indicated short-term drug delivery. It was concluded that the proposed drug-loaded membrane can be used as wound dressing, specifically, in treating skin burns.     

Total Long-Chain n-3 Fatty Acid Intake and Food Sources in the United States Compared to Recommended Intakes: NHANES 2003–2008

The American Heart Association recommends consuming fish (particularly oily fish) at least two times per week, which would provide ≈ 0.5 g/day of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) for cardiovascular disease risk reduction. Previous analyses indicate that this recommendation is not being met; however, few studies have assessed different ethnicities, subpopulations requiring additional n-3 fatty acid intake (i.e., children and pregnant and/or lactating women), or deciles of intake. Data from the National Health and Nutrition Examination Survey 2003–2008 was used to assess n-3 fatty acid intake from foods and supplements in the US population, according to age, sex, and ethnicity. A unique “EPA equivalents” factor, which accounts for potential conversion of shorter-chain n-3 fatty acids, was used to calculate total long-chain n-3 fatty acid intake. Data are reported for 24,621 individuals. More than 90% consumed less than the recommended 0.5 g/day from food sources (median = 0.11 g/day; mean = 0.17 g/day). Among the top 15% of n-3 fatty acid consumers, fish was the largest dietary contributor (71.2%). Intake was highest in men aged 20 years or more, and lowest in children and women who are or may become pregnant and/or are lactating. Among ethnicities, intake was lowest in Mexican-Americans. Only 6.2% of the total population reported n-3 fatty acid supplement use, and this did not alter median daily intake. Additional strategies are needed to increase awareness of health benefits (particularly among Mexican-Americans and women of childbearing age) and promote consumption of oily fish or alternative dietary sources to meet current recommendations.