Sequences and Structures of Retinal Proteins

The past few years have been an exciting period in the field of the structure of retinal proteins, especially the visual pigments. A significant achievement is the 9 Å projection map of bovine rhodopsin. This not only provides knowledge of the three-dimensional structure of visual pigments, but also establishes a more reliable basis for the structural modeling of all the G-protein-coupled receptors. The modeling of such three-dimensional structures will eventually lead to a better understanding of the function of visual pigments and other G-protein-coupled receptors. Our goal in this article is to draw attention to recent developments in the structure of retinal proteins, with special emphasis on visual pigments. By combining a wide range of existing experimental data with the results of theoretical calculations, a new three-dimensional structure of visual pigments, which differs from the models which have so far been reported, is proposed.     

ACID EFFECTS ON TOLUENE-ACETONE-WATER SYSTEM

The effect of the addition of acids on the ternary system of toluene-acetone-water was experimentally investigated at 30°C. Generally, the degree of solute recovery was dependent on acid concentration and its type. The tie-line data has been correlated by Hand's plots as well as by the Eisen-Joffe equation and the coefficients for the latter are presented.     

Dynamic stability and optimal excitation control of doubly excited synchronous machine: Influence of load characteristics

This paper is concerned with the effects of connected loads on the optimal excitation control and dynamic stability of power systems, incorporating doubly excited synchronous generators. The system studied is made up of a generating unit with local load and a transmission line connecting the machine to an infinite bus.A number of operating conditions are examined, and different system parameters used in order to identify effects attributable to the regulators, tie-line reactance, and the characteristics of the local load. For purposes of comparison, corresponding results of dynamic stability studies are also presented for the system with a conventional synchronous machine.     

Gilbert-Varshamov bound for Euclidean space codes overdistance-uniform signal sets

In this correspondence, in an extension of Piret's bound for codes over phase-shift keying (PSK) signal sets, we investigate the application of the Gilbert-Varshamov (GV) bound to a variety of distance-uniform (DU) signal sets in Euclidean space. It is shown that four-dimensional signal sets matched to binary tetrahedral, binary octahedral, and binary icosahedral groups lead to better bounds compared to the bounds for signal sets matched to dicyclic groups with the same number of signal points and comparable symmetric PSK signal sets     

Effects of moisture and other contaminants in friction composites

The role of water and other contaminants like salt water, iso-octane, and ethylene glycol on neat resin, composites, and friction materials have been investigated. The maximum solvent uptake and the diffusion coefficient of the solvent in these systems were determined and the experimental data was fitted to a Fickian model. The nature of the diffusion process was determined in each case and deviations from Fickian behavior were accounted for. For the neat resin and the composites, the diffusion coefficients of the liquids were of the order of 10^?10 cm²/s. After exposure to these contaminants, mechanical properties of all the systems were determined and a general degradation in properties was found. The flexural strength and fracture toughness showed reduction in values while the flexural modulus was not affected.     

FA composition of crude oil recovered from catfish viscera

The FA composition of crude catfish oil recovered from whole viscera, digestive tract, liver, gallbladder, and visceral storage fat was determined and compared with that of fillet and nugget (abdominal portion). About 34% crude fat (wet basis) could be recovered from the whole catfish viscera. FA found in crude catfish visceral oil were C14∶0, C16∶0, C16∶1, C18∶0, C18∶1, C18∶2, C18∶3, C20∶0, C20∶1, C20∶2, C20∶3, C20∶4, and C22∶6, the predominant FA being C18∶1, C16∶0, C18∶2, and C18∶0. Catfish visceral oil was characterized by a high level of unsaturated FA, which was similarly found in fillet and nugget. Total unsaturated FA in visceral oil amounted to 261.3 mg/g (dry basis) compared to that of fillet (259.3 mg/g) and nugget, (307.6 mg/g). The whole viscera contained 4.2 mg/g DHA compared to that of gallbladder (9.2 mg/g), fillet (9.3 mg/g), and nugget, (10.7 mg/g). The total n−3 FA in the whole and/or portioned visceral ranged from 4.3 to 20.9 mg/g.     

Study of fluid flow and residence-time distribution in a continuous slab casting mould

The fluid-flow pattern and residence-time distribution (r.t.d.) of the fluid in a continuous casting mould have been studied using a water model. The two recirculating zones below the discharge ports have been found to be asymmetric. The effect of casting speed, discharge port diameter, shroud well depth and the immersion depth on r.t.d. have been investigated. The r.t.d. curve has been well represented by a model of two backmix cells of equal volume in series. The exit of the fluid has been found to be non-uniform across the cross-section of the mould. The fluid-flow pattern has been observed to change with time in a random fashion. Dead volume of upto 31.8% has been found with smaller discharge ports.     

Miniaturization of low cycle fatigue‐testing of single crystal superalloys at high temperature for uncoated and coated specimens

A newly developed miniature specimen and respective fixture for high temperature low cycle fatigue testing of nickel based single crystal superalloys is presented. Miniaturization allows the preparation of test specimens in all main crystallographic orientations of the cubic nickel crystal using laboratory sized material samples and enables excellent utilization of the costly material. The specimen geometry is optimized by means of parameter studies employing numerical calculations such that for the main crystallographic orientations the stress concentration at the fillet between gauge length and specimen head is minimized, and failure is likely to occur within the gauge length. The designed fixture allows easy specimen mounting and provides sufficient support for applying an extensometer for strain measurement. Protective metallic coatings against oxidation can be applied on the specimen by plasma spraying for studying the effect of coatings on the fatigue lifetime. The functionality of the specimen geometry and fixture design for low cycle fatigue testing is demonstrated for temperatures up to 950 °C.     

Zero-Degree algorithm for Internet GateWay placement in backbone wireless mesh networks

Internet GateWays (IGWs) are responsible for connecting the backbone wireless mesh networks (BWMNs) to the Internet/wired backbone. An IGW has more capabilities than a simple wireless mesh router (WMR) but is more expensive. Strategically placing the IGWs in a BWMN is critical to the Wireless Mesh Network (WMN) architecture. In order to solve the problem of IGWs placement in BWMNs, a novel algorithm is proposed in this paper. The new algorithm is involved in placing a minimum number of IGWs so that the Quality of Service (QoS) requirements are satisfied. Different from existing algorithms, this new algorithm incrementally identifies IGWs and prioritively assigns wireless mesh routers (WMRs) based on the computed degree of WMRs to identified IGWs. Performance evaluation results show that proposed algorithm outperforms other alternative algorithms by comparing the number of gateways placed in different scenarios. Furthermore, having control of the distribution of IGWs in order to locate them closest to available Internet/wired network connection points is an added advantage of this algorithm.