Betatron harmonic radiation from harmonic undulators

Abstract

In this paper we discuss the spectral properties of undulator radiation with a harmonic undulator field to include the off-axis field structure in the analysis. The analysis is aimed to clarify the role of betatron oscillation in a harmonic undulator which arise when the electrons are emitted off the undulator axis.     

Generation of optimal control policy for flexible manufacturing cells: A Petri net approach

For flexible manufacturing cells (FMCs), the major control problem is to determine the optimal part routeing and machines dispatching policy. In this research, we present a methodology for generating optimal operating strategies for FMCs. The methodology is built on two techniques: stochastic timed Petri net (STPN) and Markov decision process (MDP). The operating strategy devised with the proposed methodology is deadlock-free and provides the best performance given a set of system parameters (machines, parts, machining times, etc.). Generation of programmable logic controller (PLC) codes is greatly facilitated as the generated strategy can be mapped directly to a ladder diagram representing the PLC code. The objective of real-time optimal control could then be achieved with this type of controller. An example is provided to illustrate the methodology.     

Prospects of highly efficient AlGaInP based surface emitting typering-LED for 50 and 156 Mb/s POF data link systems

The detail design and performance of the surface emitting type visible light emitting diode (LED) is described for using in the plastic optical fiber (POF)-based data links. The diode showed brightness as high as 3.5 mW@100 mA (dc) and also exhibited the beam divergence angle as low as 10° with using of well designed plastic lens. The using of LED with plastic lens helps to attain also the coupling efficiency over 70% with POF. The temperature rise of the ring LED under operation is also estimated to be 9 and 6°C less than the conventional diode at 50 and 35 mA bias currents, respectively. Transmission experiments reveal that the diode is suitable for 50 and 156 Mb/s 100 m POF-based data links     

Linearized Model of Object Caching and Heuristic Solution

Object-oriented (OO) technologies have become widely adopted in enterprise applications due to the additional functionality and flexibility they provide to these applications. At the same time, however, OO technologies also require significant amounts of computational power to support, greatly impacting the performance and scalability of such applications. A very popular solution to mitigate this problem is object caching. In this paper, we show how the application of object caching maps into an optimization problem. In particular, we focus on the design-time decision of determining which objects should be candidates for caching. Choosing the cacheable objects is an important decision since it can have a significant impact on application performance. We formulate this problem as a linear integer program and present a heuristic solution approach. We also demonstrate, through a set of experiments, that our heuristic provides solutions that are reasonably close to optimal. Our contribution is a model and an efficient solution approach for this model that can help application developers to make more informed cacheability decisions and thereby improve application performance and scalability.     

Invasion-inhibitory antibodies inhibit proteolytic processing of apical membrane antigen 1 of Plasmodium falciparum merozoites

Apical membrane antigen 1 (AMA-1) is a promising vaccine candidate for Plasmodium falciparum malaria. Antibodies against AMA-1 of P. falciparum (PfAMA-1) interrupt merozoite invasion into RBCs. Initially localized within the apical complex, PfAMA-1 is proteolytically processed and redistributed circumferentially on merozoites at about the time of their release and invasion into RBCs. An 83-kDa precursor form of PfAMA-1 is processed to 66-kDa and then to 48- and 44-kDa products. We show that, even at low concentrations, IgG antibodies against correctly folded recombinant PfAMA-1 cross-linked and trapped the 52-, 48-, and 44-kDa proteolytic products on merozoites. These products are normally shed into the culture medium. At higher concentrations antibodies inhibited invasion into RBCs and caused a reduction in the amount of 44- and 48-kDa products, both on merozoites and in the culture medium. A corresponding increase also occurred in the amount of the 66- and 52-kDa forms detected on the merozoites. These antibodies also prevented circumferential redistribution of AMA-1. In contrast, monovalent invasion-inhibitory Fab fragments caused accumulation of 66- and 52-kDa forms, with no cross-linking, trapping, or prevention of redistribution. Antibodies at low concentrations can be used as trapping agents for intermediate and soluble forms of AMA-1 and are useful for studying proteolytic processing of AMA-1. With this technique, it was confirmed that protease inhibitor chymostatin and Ca2+ chelators can inhibit the breakdown of the 66-kDa form. We propose that antibodies to AMA-1 capable of inhibiting erythrocyte invasion act by disrupting proteolytic processing of AMA-1.     

Activated carbon + HFC 134a based two stage thermal compression adsorption refrigeration using low grade thermal energy sources

A thermodynamic analysis is presented for the two stage thermal compression process for an adsorption refrigeration cycle with HFC-134a as the working fluid and activated carbon as the adsorbent. Three specimens of varying achievable packing densities were evaluated. The influence of evaporating, condensing/adsorption and desorption temperatures was assessed through three performance indicators, namely, the uptake efficiency, the coefficient of performance and the exergetic efficiency. Conditions under which a two stage thermal compression process performs better than the single stage unit are identified. It is concluded that two stage thermal compression will be a viable proposition when the heat source temperature is low or when adsorption characteristics are weak or when adequate packing densities are difficult to realize.     

Biting behaviour and biting rhythm of potential Japanese encephalitis vectors in Assam

Studies on biting behaviour and biting cycles of medically important mosquitoes were carried out in Madhupur village and Tarajan tea estate of upper Assam. Collections were made off human baits outdoors and indoors and off cattle bait outdoors from August 1991 to July 1992. Human bait collections were performed using the 'stationary direct bait' technique. A total of 9,072 adult host seeking female mosquitoes representing 26 species and 5 genera were collected off baits of which 36.9% were collected off human baits and the rest from cattle. All mosquitoes were primarily zoophilic, although significant numbers were collected biting man outdoors. Biting preferences of important Japanese encephalitis (JE) vectors for man and cattle were studied using outdoor man:outdoor cattle ratio (attraction ratio = AR). Culex quinquefasciatus was attracted towards human baits the most (AR = 8.1:1), followed by Cx. bitaeniorhynchus (AR = 1.6:1) and Mansonia annulifera (AR = 1.3.1). The hourly biting activity of important JE vectors throughout the night on two bait types was also studied using three point moving averages. Hierarchical agglomerative cluster analysis was used to compare and classify mosquitoes on the basis of their similarity in biting rhythms.     

Synthesis and characterization of conducting poly (1-aminonaphthalene), poly (2-aminonaphthalene) and poly (aniline-co-1-aminonaphthalene)

Poly (1&2)-aminonaphthalene and poly (aniline-co-1-aminonaphthalene) have been synthesized in high yields by chemical oxidative polymerization method. The polymers are soluble in polar solvents such as DMSO, NMP etc. In PNA-2 as head-to-tail coupling cannot occur, the electrical conductivity is lower than PNA-1. The copolymer exhibits distinct morphology, higher viscosity, characteristic exciton peak, appreciable thermal stability and electrical conductivity compared to PNA-1.