Large Duty Research Articles

Peran Pemimpin dalam Pengambilan Keputusan

In an educational institution, company or organization, of course there is a leader who manages all the smooth processes of the activities planned by the institution. A wise leader doesn't just rule, regulate and spread big promises without taking action. Active contribution from a leader is highly recommended and expected, in order to achieve all expected visions and goals. Leaders are chosen because they have more knowledge, skills and creativity than other individuals. Large duties, responsibilities and mandates will not be imposed on ordinary people. The role of leaders is very large in an organization, one of which is decision making. The decisions taken determine the conditions and situation of the organization's future development. For this reason, the role of leaders is required in making the right decisions, prioritizing common interests, and for the welfare of the organization,

Research on reverberation characteristics analysis and suppression methods for active continuous detection

Compared with the traditional active detection with monopulse periodic emission mode, active continuous detection has the advantages of large emission duty ratio and continuous acquisition of process information. It can effectively overcome the disadvantages of high false alarm probability, poor environment adaptation ability and low detection efficiency in traditional active detection, so then improving the system detection ability. But active continuous detection is also facing more serious reverberation. In order to further improve capacity, the adaptable reverberation characteristics and detection methods are carried out in this paper. On the basis of theoretical modelling, the relationship between the characteristics of the active continuous detection reverberation and the signal form, the hydrological environment and the emission power are studied. The time frequency characteristics of reverberation and the attenuation law with distance of reverberation are mastered. A reverberation suppression method based on adaptive beamforming of sub-band steered minimum variance algorithm (SSMV) is studied for active continuous detection. Considering signal bandwidth and fast convergence, etc. The relationship between sub-array partition and reverberation suppression ability is analyzed. The validity of reverberation characteristic analysis is verified by simulation, the performance of the method of reverberation suppression is verified by sea trial data processing.

Cross-layer design for reducing delay and maximizing lifetime in industrial wireless sensor networks

Low delay and long lifetime are a very important issue for industrial wireless sensor networks (IWSNs) in which it require long-time monitoring of industrial sites and respond quickly to events that is monitored; therefore, high delay communications can cause serious damage to property and personnel at industrial field. Due to delay, lifetime, and other performance involved to multiple layers, it is difficult to optimize from a single layer. Therefore, a cross-layer design optimal scheme for reducing delay and maximizing lifetime (RDML) scheme is proposed for IWSNs which is from several layers such as transmitted power, duty cycle, and node deployment positions to optimize the network performance of delay and lifetime etc. Firstly, due to the node which sends a packet within a cycle, different duty cycle leads to different selection of the modulation level, resulting in different power consumption efficiency of transmitting data. Through careful analysis, the optimal value of the duty cycle is given which has the lowest energy consumption per bit. In fact, the energy consumption of the node is not balanced. Therefore, an optimization method of changing the duty cycle is proposed. In this paper, larger duty cycle is chosen for nodes with residual energy to improve the reliability of data transmission, reducing the probability of data retransmission, so that the network delay can be reduced in IWSNs. Third, based on the previous analysis, a network optimization deployment algorithm is proposed, which not only maximizes the energy efficiency of a single node but also maximizes the network lifetime and the total network energy efficiency. Both our comprehensive theoretical analysis results indicate that the performance of RDML scheme is better than the previous studies. Relative to equal distance and optimal duty cycle scheme, the RDML scheme can reduce the delay by 19–30% and increase the lifetime by more than 43%.

Performance comparison of single-stage mixed-refrigerant Joule–Thomson cycle and reverse Brayton cycle for cooling 80 to 120 K temperature-distributed heat loads

Thermodynamic performance comparison of single-stage mixed-refrigerant Joule–Thomson cycle (MJTR) and pure refrigerant reverse Brayton cycle (RBC) for cooling 80 to 120 K temperature-distributed heat loads was conducted in this paper. Nitrogen under various liquefaction pressures was employed as the heat load. The research was conducted under nonideal conditions by exergy analysis methods. Exergy efficiency and volumetric cooling capacity are two main evaluation parameters. Exergy loss distribution in each process of refrigeration cycle was also investigated. The exergy efficiency and volumetric cooling capacity of MJTR were obviously superior to RBC in 90 to 120 K temperature zone, but still inferior to RBC at 80 K. The performance degradation of MJTR was caused by two main reasons: The high fraction of neon resulted in large entropy generation and exergy loss in throttling process. Larger duty and WLMTD lead to larger exergy losses in recuperator.

Outage Capacity for Secondary Users Due to Bandwidth Fluctuations: Multicarrier Versus Single Carrier

In this work we study the channel capacity from the point of view of a secondary user that shares the bandwidth of the channel with a primary user using dynamic spectrum access in cognitive radio.The secondary user sees bandwidth fluctuations (i.e, at any given time the bandwidth can be available or not) that impact its channel capacity. We study the outage capacity for the secondary user considering two scenarios in which the secondary user uses either a single carrier modulation for the case in which bandwidth fluctuates over the complete transmission band, and a multicarrier modulation for the case in which bandwidth fluctuations are over various transmission subbands. We derive expressions for the outage capacity of the secondary user for both single carrier and multicarrier. Results show that: (1) The outage capacity for single carrier can be higher than for multicarrier, but with a higher outage probability for single carrier than for multicarrier. In fact, a low value of outage probability for single carrier requires a duty cycle for the secondary user close to one, but this has the problem that it leaves a very short duty cycle for the primary user. (2) Although for the secondary user the outage capacity for multicarrier is smaller than for single carrier, for multicarrier lower values of the outage probability can be achieved even for short values of the duty cycle of the secondary user, allowing larger duty cycle values of the primary user. (3) For multicarrier, the outage capacity is more sensitive to changes in the duty cycle than to changes in the outage probability. To obtain a larger outage capacity with low values of both the outage probability and the duty cycle, it requires the use of a large number of subbands.

Development of a 90°/180° Upender for Large and Heavy Workpiece by Using Airbags-Drived Flipping Worktable

There is a serious security problem in the process of workpieces flipping, which restricts the increase of production capacity in manufacturing process of large workpieces applied in nuclear power equipment. The shapes and characteristics of flipping workpieces were analyzed; the general model of workpieces outer contour was established. The design goals of heavy castings and forgings cold-work turnover mechanism were formulated based on the requirements of turning process, then the basic constraint-face was build and the geometric constraint-model was uniformed. A novelty 3- DOF planar serial mechanism of heavy upender was proposed whose overall configuration consists of three movements, that is roll, mobile, folding turn, which can realize the double function of turning 90 ° and 180 ° of large workpiece as hollow cylindrical, conical and spherical crown three types. On this basis, the airbags-drived flipping worktable was designed; Topological optimization of flipping worktable was further conducted. Its key technology will provide useful ideas and references for the development of large heavy duty positioner and turnover machine with its other related equipment.

Variation in spatial and temporal kinematics of level, vertical and inverted locomotion on a stinkbug Erthesina fullo

In the learning of locomotion behavior of a stinkbug Erthesina fullo, the seeked principle of its locomotion can be an important inspiration on the design of six-legged robot. To achieve this goal, in this paper, locomotion behavior of stinkbugs on glass and plastic foam are recorded. Hereby, variation in spatial and temporal kinematics of level, vertical and inverted locomotion is analyzed. Differential leg function and adhesive mechanism as well as the advantage of non-isometric legs of insects are presented. With increasing stride frequency, the speed of level, vertical and inverted locomotion can be higher without adjusting stride length. Variation in gait characteristics between level and vertical locomotion is very little, but lower speed and larger duty factor of inverted locomotion can be occurred while climbing on glass. On the surface of vertical and inverted plastic foam, stinkbugs cannot walk steady and agilely due to its adhesive mechanism.

Test and Evaluation of Stiffness of a Pin Turning Device for Large Marine Engine Crankshafts

In order to prevent unwanted excited vibrations and to secure better machining precision in large size heavy duty machine tools dynamic stiffness is one of the most desirable and critical properties. In the past decades, many researches on machine tool stiffness test and evaluation methodology have been made. However any methodology for a Pin Turning Device (PTD), which is a special kind of turning lathe for machining big size crankshaft pins, is rarely found among them. This study proposes a test and evaluation process of stiffness of a PTD by measuring frequency response function at the tool center point (TCP). For conformance proving for the proposed methodology, stiffness of a PTD obtained by the proposed method with impact hammer test (IHT) has been compared with that determined by FEM.

Analysis of R134a–DMAC vapour absorption refrigeration system with add-on components

Abstract R134a–DMAC vapour absorption refrigeration system (VARS) needs rectifier. Because of incomplete rectification, a small amount of DMAC is carried to evaporator. It results in a temperature gradient and also formation of residual liquid in the evaporator. This liquid causes cooling loss which can be recovered significantly by using liquid vapour heat exchanger (LVHX). The same cooling temperature can be attained at a range of evaporator pressures due to the temperature gradient. For fixed cooling temperature, the system COP enhances with evaporator pressure. The enhancement rate is more when efficiencies of rectifier and LVHX are high. Efficient solution heat exchanger (SHX) is vital owing to its large heat duty. Rectifier loses its importance if high efficiency LVHX is used. Roles of these three components increase at low cooling and high sink temperatures.

Influence of Demographics on Computerized Cognitive Testing in a Military Sample

Computerized cognitive testing with software programs such as the Automated Neuropsychological Assessment Metrics (ANAM) have long been used to assess cognition in military samples. This study describes demographic influences on computerized testing performance in a large active duty military sample (n = 2366). Performance differences between men and women were minimal on most ANAM subtests, but there was a clear speed/accuracy trade-off, with men favoring speed and women favoring accuracy on the Continuous Performance Test (CPT) subtest. As expected, reaction time increased with age on most subtests, with the exception of Mathematical Processing Test (MTH). Higher education resulted in significant but minimal performance increases on Code Substitution (CDS), Matching to Sample (MSP), and Memory Search (STN) subtests. In contrast, substantial performance differences were seen between education groups on the MTH subtest. These data reveal that it is important to consider demographic factors, particularly age, when using ANAM to draw conclusions about military samples. These results also point to the importance of exploring demographic influences for all reaction time–based computerized assessment batteries.

Influence of high frequency pulse current on properties of electroformed nanocrystalline Ni–Mn alloys

The refinement of the grain size of electroformed deposits is an important way to improve the properties of the deposits. In the present study, Ni–Mn alloys in which the grain sizes approached ∼100 nm or below were electroformed by using a high frequency pulse power supply. The influence of the average deposition current density and pulse parameters on microhardness and tensile properties of the pulse electroformed Ni–Mn alloys was studied. The results show that the current parameters influence the properties of the alloys by changing their Mn content and grain size. With increase in average current density, microhardness and strength of the alloys increase and the elongation ratio decreases because of the increment of Mn content of the alloys and the decrement of grain size of the alloys. A shorter pulse on time and larger duty cycle contribute to higher microhardness and strength of the alloys.

AN UNEQUAL ACTIVISM FOR AN UNEQUAL EPIDEMIC?1

This paper observes that a substantially large moral duty of dealing with the AIDS situation in Africa has been placed on the drug companies and argues that this approach is inequitable. Using the poverty-AIDS relationship and the human rights framework it argues for a more balanced AIDS activism, which puts equal pressure on all potential stakeholders in the war against AIDS. It argues that this redistribution of the HIV/AIDS moral burden is perhaps the only hope for curbing the African AIDS epidemic that continues to ravage communities on that continent.

NONISOLATED MULTIPHASE HALF-BRIDGE-BUCK TOPOLOGY WITH INHERENT CURRENT SHARING CAPABILITY AND SOFT-SWITCHING AND COUPLED-INDUCTORS CURRENT-DOUBLER

Point-of-load DC–DC converter requirements and design are increasingly becoming stricter than ever. This is due to the required tight dynamic tolerances allowed for supply voltages and high dynamic performance demand coupled with very high power density. Moreover, as the required converter output voltage becomes smaller, higher voltage step-down ratio is required, which results in smaller switching duty cycle in the nonisolated topologies. Step-down transformer with large turns ratio is used in the isolated topologies to step-down the voltage and keep larger duty cycle. Most of the nonisolated DC–DC topologies are buck-derived and unfortunately work at hard-switching which degrades the efficiency. DC–DC interleaved buck topologies were proposed but are highly sensitive to interleaved phases asymmetry and require high performance current sharing loop. In this paper, a nonisolated multiphase nonisolated half-bridge-buck topology is presented. This topology makes it possible to achieve soft-switching, works at larger switching duty cycle with lower output voltages, and does not require current sharing loop because of the inherent current sharing capability. Moreover, a coupled-inductor current doubler topology is also presented in this paper allowing higher step-down ratio and lower output current ripple. Theoretical analysis and experimental results are presented.

Kronig–Penney model for periodically segmented waveguides

Physical insight into the propagation characteristics of periodically segmented waveguides can be obtained by viewing the guiding layer as a thin slab of an idealized infinite medium with periodic layers along the direction of propagation. One can analyze the properties of this infinite medium using a formal analogy with the Kronig-Penney model used to describe the propagation of electron wave functions in a periodic crystal potential. The model correctly gives the effective refractive index of the layer, gives insight into the electric field profiles at different points on the dispersion curve, and leads to a qualitative explanation of why the optical loss diminishes at both large and small duty cycles.

CAGE as a predictor of hazardous alcohol consumption in U.S. Army personnel.

Sensitivities, specificities, and odds ratios for hazardous drinking for various cut scores on the CAGE are computed for a large sample active duty Army personnel. Contrasts on these properties are made between the standard CAGE and a "modified CAGE" consisting of standard CAGE items and two other items dealing with problematic drinking. The role of demographic variables--gender, ethnicity, marital status, rank category, and age in mediating relationships of both versions of the screening test to hazardous drinking--is also explored. At a cutoff score of one endorsed item, odds ratios were highest for female personnel and commissioned officers.

In Situ Observation of Growing Process of Particles in Silane Plasmas and Their Effects on Amorphous Silicon Deposition

AbstractIn rf silane plasmas, growing process and behavior of dust particles and presence of negative ions are studied by square-wave-amplitude-modulating an rf discharge voltage. By combining the rf modulation method with Mie scattering methods, particle behavior together with temporal evolutions of particle size and density is revealed. While the rf modulation is effective for the suppression of particle growth, small particles are found to exist still in the discharge space for a larger duty cycle. Further, particles seem to be suspended around an rf electrode by counter balance between an electrostatic force due to time-averaged sheath electric field and a force increasing with particle size. The development of particle growth also affects the rf discharge itself, resulting in inhomogeneity of film properties. Negative ion detection is carried out as a first step for studying whether they cause the particle formation. It is found that negative ions are formed in rf silane discharges even for a low concentration of 0.5%SiH4 and their formation is due to attachment to dissociated radicals rather than dissociative attachment of SiH4.

In Situ Observation of Growing Process of Particles in Silane Plasmas and Their Effects on Amorphous Silicon Deposition

ABSTRACTIn rf silane plasmas, growing process and behavior of dust particles and presence of negative ions are studied by square-wave-amplitude-modulating an rf discharge voltage. By combining the rf modulation method with Mie scattering methods, particle behavior together with temporal evolutions of particle size and density is revealed. While the rf modulation is effective for the suppression of particle growth, small particles are found to exist still in the discharge space for a larger duty cycle. Further, particles seem to be suspended around an rf electrode by counter balance between an electrostatic force due to time-averaged sheath electric field and a force increasing with particle size. The development of particle growth also affects the rf discharge itself, resulting in inhomogeneity of film properties. Negative ion detection is carried out as a first step for studying whether they cause the particle formation. It is found that negative ions are formed in rf silane discharges even for a low concentration of 0.5%SiH4 and their formation is due to attachment to dissociated radicals rather than dissociative attachment of SiH4.

Evolution of the Lipe Hydraseal Self Contained Fluid Clutch

The Lipe Hydraseal is a new fluid clutch concept to transmit engine torque to the transmission more efficiently than previously existing methods. It can be applied to various types of vehicle from passenger cars to large heavy duty trucks or off-road equipment. It offers the smooth coupling, long life and efficiencies of an oil spray clutch without the inherent installation difficulties.

Biochemistry in New Zealand: the rewards and frustrations

When the excitement of undertaking research in North America and Europe has been experienced, the contrasts on returning to New Zealand, a far-flung outpost of biochemistry, are at first quite overwhelming. A more balanced view of the two environments emerges, however, after some period of adjustment to the conditions in New Zealand. While certain aspects of the Northern scene are missed intensely, there are rewards in working in an atmosphere where the pressures ‘to produce’ to enable job survival are considerably lower. Biochemical research in New Zealand is carried out by three principal types of laboratory : government, university or industry-oriented. The Department of Scientific and Industrial Research (DSIR) and the Ministry of Agriculture and Fisheries are government departments engaged in research. They employ biochemists and other scientists to carry out applied agricultural research relevant to New Zealand and in addition to work on some basic but allied problems. In addition, research institutes such as the Wool Research Organisation of New Zealand (Inc.) (WRONZ) and the Meat Industry Research Institute conduct research into those animal products essential to the New Zealand economy. Biochemistry is taught in six of the seven universities in New Zealand (see the accompanying map). However, the involvement varies from a relatively small commitment to a significant one with quite large departments of about fifteen academic staff. The university biochemists endeavour to pursue active research programmes. They possess a great deal of independence in choice of research and can pursue interesting problems without a great deal of pressure to produce publishable results at a hurried rate. Within the university or medical-school environments there are also units or groups of scientists studying medically related problems. These groups, which include some biochemists and are funded by the Medical Research Council of New Zealand (MRC), are gradually being disbanded, however, and the research personnel assimilated into university departments of similar interests. Can a research group without postdoctoral fellows and without ready access to international meetings be viable? Clearly it is much more difficult to maintain standards, to advance rapidly in one’s area and to make a significant contribution to biochemistry under these conditions. There are very few postdoctoral fellows throughout all research institutes in New Zealand and only a handful are biochemists. Because of the isolation of New Zealand from the major conference venues, the cost of regular attendance at international meetings is prohibitive. To some extent the DSIR overcomes these difficulties by the nature of the various sections of the Department. Each section employs a number of highly qualified people working in the same area who have the majority of their time available for research. Unfortunately biochemists within universities do not have this advantage. With a large teaching load and administrative duties it is difficult for an academic biochemist to be involved directly in carrying out his research programmes himself. The universities do not provide technical help for research. In the absence of a science equivalent of the Medical Research Council to fund research many biochemists are therefore without technicians. This means the load of the research, in the absence of ‘postdocs’, falls on the doctoral students. In general, therefore, a New Zealand biochemist graduating with a PhD will be extremely well-trained and have undertaken a rigorous research programme. Paradoxically this weakness of the overall situation for university biochemists has resulted in the production of independent innovative graduates who perform extremely well when they move into the active world centres of biochemistry. To date, money has not been made available for such graduate students to attend meetings even within New Zealand and so they have very limited opportunities to present their work. While the DSIR biochemist has a number of colleagues he can interact with on a day-to-day co-operative basis and has time to do so, the university-employed biochemist with greater independence tends to have fewer people who either have intimate knowledge of his field or have the time for close interaction. Poletti (1973) in an article on scientific research in New N221

Operating Duty of Lightning Arrester Against Switching Surges

Lightning arrester sparkover, caused by a switching surge, is considered. Under some circumstances large arrester currents flow and impose heavy duty upon the arrester characteristic elements and the series gap. Therefore, it is necessary to study previous relationships between the follow current and the circuit conditions and to test the current interruption ability of the arrester under various conditions.