Changes in the structural localization of glycogen during glucose resorption

Quantitative changes in the glycogen granula contents of the dog's small intestinal mucosa were investigated with light microscopy using Best-carmin dying. In fasting animals the glycogen could be detected in a patchy arrangement in the supranuclear cytoplasmic region of the enterocytes. During glucose abasorption glycogen appeared in continually increasing quantities also in the lamina propria. Injecting Glucagon (50-100 microgram/15') into the artery of the intestinal loop during glucose absorption, glycogen totally disappeared from the enterocytes, while it remained unchanged in the cells of the lamina propria.     

End-to-end fair rate optimization in wired-cum-wireless networks

In this paper, we address the end-to-end rate optimization problem in a wired-cum-wireless network, where CSMA/CA based wireless LANs extend a wired backbone and provide access to mobile users. The objective is to achieve proportional fairness amongst the end-to-end sessions in the network. Since the network contains wireless links whose attainable throughput is a (non-convex and non-separable) function of MAC protocol parameters, the problem requires joint optimization at both the transport and the link layers. A dual-based algorithm is proposed in this paper to solve this cross-layer rate optimization problem. It is implemented in the distributed manner, and works at the link layer to adjust scheduling rates for the wireless links in the basic service sets, and at the transport layer to adjust end-to-end session rates. We prove rigorously that the proposed algorithm converges to the globally optimal rates. Simulation results are provided to support our conclusions.     

Throughput and Fairness Guarantees Through Maximal Scheduling in Wireless Networks

The question of providing throughput guarantees through distributed scheduling, which has remained an open problem for some time, is addressed in this paper. It is shown that a simple distributed scheduling strategy, maximal scheduling, attains a guaranteed fraction of the maximum throughput region in arbitrary wireless networks. The guaranteed fraction depends on the ldquointerference degreerdquo of the network, which is the maximum number of transmitter-receiver pairs that interfere with any given transmitter-receiver pair in the network and do not interfere with each other. Depending on the nature of communication, the transmission powers and the propagation models, the guaranteed fraction can be lower-bounded by the maximum link degrees in the underlying topology, or even by constants that are independent of the topology. The guarantees are tight in that they cannot be improved any further with maximal scheduling. The results can be generalized to end-to-end multihop sessions. Finally, enhancements to maximal scheduling that can guarantee fairness of rate allocation among different sessions, are discussed.     

Leakage flux saturation effects on the transient performance of wound-rotor induction motors

The prediction of induction machine performance has traditionally been based on the constant parameter models. This approach was later replaced by considering saturation in the main flux paths. However, such models have not been sufficiently accurate for certain transient conditions such as on-line starting and short-circuit. So, an accurate study of their performance should necessarily consider the magnetic saturation effect both in the main and leakage flux paths. In this paper, an experimental procedure to determine the machine parameters and saturation characteristics is adopted. The adopted experimental procedure facilitates the measurement of both stator and rotor leakage reactance saturation characteristics. Two models of saturated induction motors are developed to predict the transient performance of a laboratory wound-rotor induction motor. The results calculated by the proposed models considering and ignoring the leakage flux saturation are compared with the experimental results. The model that considers saturation in the leakage flux paths produces more accurate transient responses.     

Acrylonitrile‐butadiene‐styrene nanocomposites filled with nanosized alumina

A polymer nanocomposite was produced by acrylonitrile‐butadiene‐styrene (ABS) and α‐alumina was prepared through sol‐gel process using aluminum nitrate and citric acid. The particle size was analyzed by X‐ray diffraction and scanning electron microscopy (SEM) studies. The nanocomposites were characterized through tensile strength, Young's modulus, strain% at break, flexural strength, flexural modulus, and impact strength. The ABS/Al₂O₃ nanocomposites are found to have slightly higher Young's modulus, but lower tensile strength, strain% at break, flexural and impact strength than the virgin ABS. But its flexural modulus increases with increasing Al₂O₃ content in ABS matrix. The d‐spacing was calculated in nanocomposites to evaluate the interaction between Al₂O₃ and ABS. The particle distributions in nanocomposites were studied by SEM. The fractured surfaces of tensile test samples were also examined through SEM and show that the ductile fracture of ABS is converted to brittle fracture with addition of Al₂O₃. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Stress relaxation behavior of glass fiber‐reinforced polyester composites prepared by the newly proposed rubber pressure molding

Stress‐relaxation behavior of glass fiber‐reinforced polyester composites, prepared by a recently developed manufacturing method called rubber pressure molding (RPM), is investigated with special reference to the effect of environmental temperature (−70°C to +100°C), fiber volume fraction (30–60%), and initial load level (1–5 kN). It is found that the stress‐relaxation rate decreases with an increase in the applied load of composites and a decrease in temperature. Below glass transition temperature, the rate of stress relaxation increases with an increase in volume fraction of fibers in the composites, whereas above glass transition temperature, it increases with a decrease in the volume fraction of fibers. The experimental results for a given composites are summarized by four values, the slopes of the two straight lines (two separate relaxation processes), and their intercepts upon the stress axis. Both the slopes are dependent upon the applied load, temperature, and volume fraction of fibers in the composites. Relaxation times in both primary and secondary are calculated over the wide range of temperatures, loads, and volume fraction of fibers in the composites. It depends strongly on the temperature, but does not depend strongly on the applied load and volume fraction of fibers. The performances of the composites are also evaluated through conventional compression‐molding process. The rate of stress relaxation is small when the composites are made of newly proposed RPM technique when compared with the conventional process. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Optimal approximation of asymmetric type fractional-order bandpass Butterworth filter using decomposition technique

In this letter, the optimal rational approximation of fractional-order bandpass Butterworth filter (FOBBF) is presented. The transfer function of the FOBBF is decomposed into a multiplication of first-order and second-order terms. As a result, the design stability conditions can be easily satisfied using only the variable boundary constraints. The proposed technique generalizes the symmetric fractional-order roll-off characteristic as only a special case of the asymmetric one. Several examples are presented to validate the modeling efficacy.