727 research outputs found
Separation, Bioactivity and Dissipation of Enantiomers of the Organophosphorus Insecticides Fenamiphos
No full textOral administration of milk from cows immunized with human intestinal bacteria leads to significant improvements of symptoms and signs in patients with oral submucous fibrosis.
No full textPhotosynthetic Mechanisms of Weeds in Taiwan
No full textOne hundred and one species (in 36 families) of weeds on cultivated land in Taiwan were investigated for the occurrence of Kranz leaf anatomy and activities of key enzymes of C-4 photosynthesis to determine their photosynthetic mechanisms. Based on the anatomical and biochemical analyses, 75 species were found to possess the C-3 and 26 species the C-4 pathway of photosynthetic CO2 fixation. Among the 26 C-4 species, 15 species are in Gramineae, 6 in Cyperaceae, 2 each in Euphorbiaceae and Amaranthaceae, and 1 in Portulacaceae. Two C-4 species in the Gramineae, namely Digitaria radicosa (Presl) Miq. and Sporobolus fertilis (Steud.) Clayton, were recorded as C-4 plants for the first time. The biochemical subdivisions of these C-4 weeds were also determined. As in the natural C-4 populations, the NADP-malic enzyme subtype of C-4 photosynthesis dominates the list of C-4 weeds on this island (62%), while the PEP carboxykinase subtype is relatively rare (12%). NAD-malic enzyme subtype has an intermediate representation (26%). The high proportion of weeds in Taiwan being C-3 plants is noteworthy, and it may be accounted for by the high precipitation in this subtropical island
Analysis of Single Buffer Random Polling System With State-Dependent Input Process and Server/Station Breakdowns
No full textModels and analytical techniques are developed to evaluate the performance of two variations of single buffers (conventional and buffer relaxation system) multiple queues system. In the conventional system, each queue can have at most one customer at any time and newly arriving customers find the buffer full are lost. In the buffer relaxation system, the queue being served may have two customers, while each of the other queues may have at most one customer. Thomas Y.S. Lee developed a state-dependent non-linear model of uncertainty for analyzing a random polling system with server breakdown/repair, multi-phase service, correlated input processes, and single buffers. The state-dependent non-linear model of uncertainty introduced in this paper allows us to incorporate correlated arrival processes where the customer arrival rate depends on the location of the server and/or the server's mode of operation into the polling model. The author allows the possibility that the server is unreliable. Specifically, when the server visits a queue, Lee assumes that the system is subject to two types of failures: queue-dependent, and general. General failures are observed upon server arrival at a queue. But there are two possibilities that a queue-dependent breakdown (if occurs) can be observed; (i) is observed immediately when it occurs and (ii) is observed only at the end of the current service. In both cases, a repair process is initiated immediately after the queue-dependent breakdown is observed. The author's model allows the possibility of the server breakdowns/repair process to be non-stationary in the number of breakdowns/repairs to reflect that breakdowns/repairs or customer processing may be progressively easier or harder, or that they follow a more general learning curve. Thomas Y.S. Lee will show that his model encompasses a variety of examples. He was able to perform both transient and steady state analysis. The steady state analysis allows us to compute several performance measures including the average customer waiting time, loss probability, throughput and mean cycle time.</jats:p
[[alternative]]The effect of precipitation hardening heat treatment on mechanical properties of A206 aluminum alloy
No full text[[abstract]]本研究主要是探討析出硬化處理對於A206鋁合金之顯微組織和機械性質之
影響。實驗結果指出，固溶處理後於常溫自然時效24小時，再進行155
.degree.Ｃ之人工時效處理時，強度最佳者發生在時效25-30小時處，其
抗拉性質約為:T.S.=43-45 kg/square millimetre，Y.S.=28-29 kg/
square millimet ，El.=12-8%。於188.degree.Ｃ 進行人工時效時，強
度最佳者發生在時效8-12小時處，其抗拉性質約為 :T.S.=42-43 kg/
square millimetre，Y.S.=36-37 kg/square millimetre，El.=8-6%。比
較155.degree.Ｃ和 188.degree.Ｃ時效處理之抗拉性質可知，二者之抗
拉強度近似，但前者所得之降伏強度較後者約低20-30%，而前者之伸長率
則為後者之1.5-2倍。在鑄造狀態下，CuAl2呈大顆粒之島嶼狀，主要析出
在晶界上，而少部份在晶粒內。在晶界處亦可發現孔洞。為使CuAl2能完
全固溶，故固溶時間 (在527.degree.Ｃ之固溶溫度)應在16小時以上。經
固溶處理後，孔洞仍舊存在，但有球化及細化之傾向。另在晶界處可發現
共晶再熔化現象。為避免此問題，除了固溶處理時之升溫速率及爐溫需嚴
加控制外，建議以二段式或三段式加熱，且第一段之溫度最好設定在500.
degree.Ｃ以下，而最後固溶溫度不可超過530.degree.Ｃ。在鑄造過程中
，為避免滯流(misrun)和熱裂(hot tear)現象，必須適當控制澆鑄溫度(
對金屬模而言)。此外，鑄件及流路設計亦須加以考慮。
Underwater spark discharge with long transmission line for cleaning horizontal wells
No full textA transmission line is discussed for application in an underwater spark-discharge technique in the cleaning of a horizontal well by incorporating a power-transmission model into the simulation. The pulsed-spark-discharge technique has been proposed for clogged-well rehabilitation, because it removes incrustations that are attached to well screens by using strong pressure waves that are generated by the rapid expansion of a spark channel. To apply the pulsed-spark-discharge technique to the cleaning of horizontal wells, the coaxial cable between the pulsed power supply and the spark gap as a load needs to be extended to a few hundred meters. Prior to field application, pulsed-spark-discharge experiments were conducted and the role of the transmission line was examined using an improved simulation model. In the model, a non-linear interaction of the spark channel and the capacitor bank is described by the pulse-forming action of the coaxial cable. Based on the accurate physical properties of the water plasma, such as the equation of state and electrical conductivity within the region of interest, the amount of energy contributed to the development of a shock wave was evaluated. The simulation shows that if the initial conditions of the spark channel are the same, no further reduction in strength of the pressure wave occurs, even if the cable length is increased above 50 m. Hence, the degraded peak pressure that was observed in the experiments using the longer cable is attributed to a change in the initial condition of the spark channel. The parametric study suggests that the low initial charging voltage, the high ambient water pressure, and the long cable length yield the low initial spark-channel density, which results in a reduced peak pressure. The simulation of line charging is presented to discuss the principle of disturbing the pre-breakdown process by an extended cable. © 2017 Author(s).OAIID:RECH_ACHV_DSTSH_NO:T201719639RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A080568CITE_RATE:0DEPT_NM:에너지시스템공학부EMAIL:[email protected]_YN:NN
A Study of Zeolite Membrane Material Balance and Commercialization Potential
No full textabstract: The United States and most of the world is pushing to significantly reduce carbon emissions, with many countries intent on fostering carbon negative energy processes to offset ozone depletion and climate changes. 30% of the U.S. greenhouse gas emissions are generated from the combustion of fossil fuels to generate electricity1. Current commercial IGCC carbon capture processes employ a capital and operating cost intensive water-gas shift reaction facilitated by a high temperature reactor followed by a low temperature reactor and an amine absorber to separate the hydrogen and carbon dioxide streams to capture the carbon. Dr. Jerry Y.S. and his laboratory at Arizona State have developed a hydrogen permselective MFI type ZSM-5 zeolite membrane reactor that effectively facilities the water gas shift reaction with high conversion and separates the CO2 and H2 streams during reaction to generate ultrapure retentate and permeate streams. The membrane, formed by secondary free growth, is synthesized on an ultrapure a-alumina membrane support currently purchased from an outside vendor. The purpose of this study was to design an α-alumina support processing plant with capability to supply one full-scale commercial reactor annually with membranes. The design yielded a DCFRoR of 71% for a 20-year project life. A zeolite membrane processing material balance was conducted using alumina support as the raw material. The study showed very low material costs and consumption rates for all materials except a gas used to refine the membrane after processing. The results of both studies were favorable enough to suggest further study
Democratization and Institutionalization-- A Reflection of Latin American Experience
No full text本文適過解放、自由化、民主化的名詞解析，以比較眼光分析拉丁美洲的民主化困局。作者以此一分析架構，初步檢討拉丁美洲「民主─威權」循環模式的成因及轉型的關鍵因素，可做為分析拉丁美洲政局的一項參考架構。This essay compares and analyses the concepts of liberation, liberalization, democratizations and their interactions in Latin American politics. According to this analytical framework, the author makes a preliminary analysis of the “democracy-authoritarianism-democracy” cycle in the Latin political history. This essay also discusses the causes and consequences of liberalization and democratization during the 1970’s and 1980’s
Development of a soft x-ray (SXR) array diagnostic system on versatile experiment spherical torus (VEST)
No full text© 2022 Author(s).A new soft x-ray (SXR) array diagnostic system has been developed on versatile experiment spherical torus (VEST) for measurements of 2D SXR emissivity profile and identification of poloidal mode structure. Through tomographic inversion techniques, 2D SXR emissivity profile can be acquired from the line-integrated SXR data, which enables the visualization of mode structure of plasma instability, such as the magnetohydrodynamics mode. The SXR array diagnostic system consists of two 20-channel arrays positioned at the middle and the top on the same poloidal plane for horizontal and vertical lines of sight, respectively. Each array of the diagnostic system uses absolute extreme ultraviolet photodiode array as the detector. To apply appropriate filters (up to four) for different energy regimes without breaking the vacuum, a filter wheel and its rotatable vacuum feed-through are installed behind the pinhole. SXR data are acquired with a digitizer at the sampling rate of up to 125 MHz. Finally, we discuss initial measurement data obtained from Ohmic plasma in VEST.N
A bibliometric analysis of the performance of Water Research
Full text link[[abstract]]This paper presents a detailed chronological survey of papers published in the journal titled Water Research which started publication since 1967. This current investigation reviews publication patterns between 1967 and 2008. An analysis of the research performance according to publication output, distribution of words in article title, author keywords, and keywords plus. Performances of countries, institutes, and authors, including total, single, collaborative, first author, and corresponding author publications were analyzed. The most-frequently cited articles each year and the articles of the highest impact in 2008 were also reported. Results showed that ‘‘activated sludge’’ was the most frequently used author keyword, followed by ‘‘adsorption,’’ and ‘‘drinking water.’’ Authors from 114 different countries/territories published in the journal, with the most articles submitted by authors from the USA
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