Multipurpose controller synthesis in discrete LQG optimal systems

This paper presents a design algorithm to synthesize a discrete-time linear-quadratic-gaussian (LQG) optimal controller that simultaneously ensures (i) input–output decoupling; (ii) pole and zero placement; and (iii) robust stability in the presence of plant perturbation. Two weighting matrices Q(Z) and R(Z) of the quadratic cost functional are shaped to synthesize an optimal controller to achieve the stated design goals.     

Computer-Assisted Identification of Bacteria on Hot-Boned and Conventionally Processed Beef

Mesophilic and psychotrophic bacteria (706 isolates) obtained from hot-boned and conventionally processed beef at the time of fabrication and after 14-day vacuum storage at 2°C were analyzed by computer-assisted numerical taxonomy (108 attributes per isolate). There was no significant difference in terms of the number of phenons between hot-boned and conventionally processed beef both at the time of fabrication and after storage. Before storage, 24 mesophilic phenons and 11 psychrotrophic phenons were characterized. After storage in vacuum bags, there were 13 mesophilic phenons and 6 psychrotrophic phenons. The after storage flora consisted mainly of Streptococcus and Lactobacillus from both hot-boned and conventionally processed beef.     

液压挤压对复合铸造Al3003/Al4004包覆材料显微组织的影响(英文)

研究液压对混合复合铸造Al 3003/Al 4004包覆材料微观组织变化的影响。复合铸造Al 3003/Al 4004包覆材料试样为圆形,由Al 3003(外部)和Al 4004(内部)材料组成。采用液压设备,在温度423 K、挤压比5的条件下制造试样。在挤压之前,Al 4004材料的直径为80 mm,Al 3003材料的厚度为35 mm,在挤压后,2种材料的直径和厚度分别为30 mm和5 mm。研究了2个试样的微观组织和硬度。在挤压之前,复合铸造Al 3003/Al 4004包覆材料横截面的硬度以抛物线的形式向中心增大。然而,在挤压后,Al 4004材料的硬度几乎没有变化。在挤压之前,Al 3003和Al 4004材料的界面存在大量直径超过1 mm的大空洞,这些大空洞随着液压过程的进行而消失。     

Linear Programming and Response Surface Methodology to Optimize Surimi Gel Texture

A formulation optimization study was conducted on surimi gels prepared with starch, and/or raw egg white employing the stepwise method (SM), linear programming (LP), and response surface methodology (RSM). At 78% moisture, the greatest gel strengthening and reduction of expressible moisture occurred at 8% starch, 6% egg white, or a combination of 5% starch and 5% egg white for SM, 5.33% starch and 4.33% egg white for LP, and 3.5% starch and 5% egg white for RSM. RSM resulted in gels with the greatest strength (compressive and penetration forces), followed by LP and SM. The RSM enabled more accurate prediction of textural behavior of final product at various ingredient combinations than the SM or LP.     

基于PenTile RGBWTM算法的高像素密度a-Si TFT移动液晶显示屏

采用传统的移动设备设计规则,基于PenTile RGBWTM算法开发了a-Si TFT移动液晶显示屏。将AFFS模式和PenTile RGBWTM算法相结合,制作的TFT液晶屏获得了超过200 cd/ m2的高亮度,500∶1的高对比度,以及达到VGA标准,可以清晰显示互联网网页的高分辨率。     

A SURVEY OF ARYLAMINE N-ACETYLTRANSFERASE ACTIVITY IN COMMON FRUITS AND VEGETABLES

The N-acetyltransferase activity was determined in 58 common fruits and vegetables. The assay was based on acetylation of 2-aminofluorene or p-amino-benzoic acid, followed by high pressure liquid chromatographic analysis of products and remaining nonacetylated substrate. The highest specific activities were observed in Balsam pear which contained 17.37 ± 1.45 N-acetyl aminofluorene nmole/min/mg protein and 46.27 ± 6.87 N-acetyl p-aminobenzoic acid nmole/min/mg protein. N-acetyltransferase activities within the remaining 57 foodstuffs analyzed ranged from none detected to 3.39 ± 0.72 N-acetyl aminofluorene nmole/min/mg protein and none detected to 32.45 ± 6.55 N-acetyl p-aminobenzoic acid nmole/min/mg protein. This is the first demonstration of acetyl CoA: arylamine N-acetyltransferase activity in common foodstuffs.     

EFFECT OF CHLORINE TREATMENT ON CUT WATER CRESS AND ONION

Chlorine treatment was evaluated for cut vegetables to reduce microbial populations and improve keeping quality. Water cress and onion were selected because they are representative vegetables having high potential for processing into cut prepared products. Cut water cress had a high initial microbial contamintion of 10^7.5 cfu/g, while cut onion had only 10^1.7 cfu/g. The cut produce was treated by soaking in chlorine solutions of different concentrations at 25C for 1 min. Treatment with ≤100 ppm chlorine effectively reduced the microbial load of the produce without significant quality losses. High concentrations of chlorine resulted in greater microbial proliferation after 7 days, ascorbic acid destruction and significant color change in stored cut vegetables. The effectiveness of chlorine treatment was limited to short-term storage of precut vegetables, and did not provide extended shelf-life.     

Application of signal processing techniques to the detection of tip vortex cavitation noise in marine propeller

The tip vortex cavitation and its relevant noise has been the subject of extensive researches up to now. In most cases of experimental approaches, the accurate and objective decision of cavitation inception is primary, which is the main topic of this paper. Although the conventional power spectrum is normally adopted as a signal processing tool for the analysis of cavitation noise, a faithful exploration cannot be made especially for the cavitation inception. Alternatively, the periodic occurrence of bursting noise induced from tip vortex cavitation gives a diagnostic proof that the repeating frequency of the bursting contents can be exploited as an indication of the inception. This study, hence, employed the Short-Time Fourier Transform (STFT) analysis and the Detection of Envelope Modulation On Noise (DEMON) spectrum analysis, both which are appropriate for finding such a repeating frequency. Through the acoustical measurement in a water tunnel, the two signal processing techniques show a satisfactory result in detecting the inception of tip vortex cavitation.     

Cr-Si粉末冶金工艺及其物理-力学性能

粉末冶金制作法主要有热压(HP)、热等静压(HIP)及常压烧结(Sinter)三种.采用热压及热等静压法可以很容易地得到高致密化的高温金属硅化物,但若要进行大尺寸的产品烧结,必须提升生产设备的规格和能力,例如加大热压机力吨位、扩大热压炉腔体等,致使设备投资及生产成本相对昂贵.所以大部分厂商宁可采用常压烧结法,虽然该法的高致密化工艺条件不易控制,却因可以制作大尺寸金属硅化物,加上设备投资及生产成本相对降低,使许多大厂已投入相当大的人力和物力在开发此工艺.该文作者试用不同真空烧结温度,造成Cr-Si合金粉末烧结性质的差异,探讨稳定而可大量生产的可行性;并通过对温度的控制,来改善Cr-Si的物理性质与力学性质.结果表明,提高烧结温度会使Cr-Si合金产生部分液相烧结的现象,从而使孔隙率显著下降;但显微结构也随之有偏析与晶粒粗化的现象.     

Effects of honing treatment on AIP-TiN and TiAlN coated end-mill for high speed machining

The objective of this work is to compare the tool performance of TiN and TiAlN coated carbides end-mills deposited by an arc ion plating (AIP) method, using honing treatment to polish the cutting edge surface sleekly. The curve of surface roughness versus honing time showed a rapid improvement initially and thereafter became steady, manifesting a saturation effect. The optimal honing time related to surface roughness was determined to be approximately 20 s. As the surface roughness increased, the critical loads reduced. At an average surface roughness (Ra) of 0.028 μm, the highest critical loads of TiN and TiAlN coating layers were 98 and 114 N, respectively. Tool performances of uncoated and coated tools were conducted under high speed machining (HSM) of AISI D2 cold-worked die steel (62 HRC). Consequently, the TiAlN coated end-mill using honing treatment showed excellent tool life under HSM conditions.