Effect of Chemical Structure and Molecular Weight on High-Temperature Stability of Some Fomblin Z-Type Lubricants

High-temperature stability of a series of Z-type PFPE lubricants with different MW and end-groups have been studied by TGA, GPC, and FT-IR. It was found that, in air and at elevated temperatures, the weight-loss of low-MW Zdols is due to evaporation while the weight-loss of high-MW Zdols is initiated by thermal oxidative decomposition. The experimental results also show that the end-groups have a significant effect on the decomposition mechanism. For Zdols that have hydroxyl end-groups, the initiation of decomposition reaction is oxidative in nature. For Zs that have perfluoromethyl end-groups, the decomposition is a thermal depolymerization reaction.     

Aerated membrane‐attached biofilm reactor as an effective tool for partial nitrification in pretreatment of anaerobic ammonium oxidation (ANAMMOX) process

BACKGROUND: A laboratory‐scale membrane aeration bioreactor was employed to treat synthetic ammonium‐rich wastewater to yield an appropriate NH₄⁺/NO₂^? ratio for anaerobic ammonium oxidation (ANAMMOX). The main objectives of this study were to steadily obtain 50% partial nitrification in batch experiments, to evaluate the effects of aeration and to identify the dominant bacterial community of the biofilm for partial nitrification. RESULTS: Some of the ammonium in the synthetic wastewater was partially nitrified. A suitable NH₄⁺/NO₂^? ratio (1:1 to 1:1.3) for the ANAMMOX process was obtained after 24 h. The dissolved oxygen (DO) level in the treated water was very low (below 0.6 mg L^?1). Both the appropriate NH₄⁺/NO₂^? ratio and the low DO level make this bioreactor an ideal pretreatment system for ANAMMOX. In addition, a molecular biotechnology method was applied to prove that the ammonia‐oxidizing bacteria dominated the biofilm. CONCLUSION: This system achieved surprising cost savings in the aeration process compared with traditional aeration systems. The combination of this system with the subsequent ANAMMOX process has great potential as a favorable short‐cut in the treatment of ammonium‐rich wastewater. Copyright © 2007 Society of Chemical Industry     

Parallel VLSI design for a real-time video-impulse noise-reduction processor

High-quality televisions (TVs) such as improved digital TV, enhanced TV, and high-definition TV have become popular in recent years. However, impulse noise affects TV broadcasts. This paper proposes an efficient noise-removal algorithm using an adaptive digital signal-processing approach. Simulations have demonstrated that the new adaptive algorithm could efficiently reduce impulse noise even in highly corrupted images. In order to achieve real-time implementation, a cost-effective architecture is proposed using a parallel structure and pipelined processing. The proposed processor can achieve the throughput rate of 45M pixels/s using only 4k gates and two line buffers. Unlike median-filtering chips, this processor provides better filtering quality and its circuit is much less complex.     

Compatibility of a nonthoracotomy lead system with a biphasic implantable cardioverter-defibrillator. Cadence-Endotak 60-Series IDE investigators

This prospective multicenter study was conducted under the Food and Drug Administration Investigational Device Exemption to evaluate the safety and efficacy of the combination of the Cadence implantable defibrillator (Ventritex, Inc.) and 60-series Endotak C leads (Cardiac Pacemakers, Inc.). Implantation was attempted in 148 patients with hemodynamically compromising ventricular tachycardia or fibrillation (VF), or with pace-terminable ventricular tachycardia. The system was successfully implanted in 97% of patients, with 96% of implants in a transvenous-lead-alone configuration. At implantation, the defibrillation threshold was 455 +/- 94 V (14 +/- 6 J) for lead-alone patients and 532 +/- 40 V (19 +/- 3 J) for those requiring a subcutaneous patch. VF conversion efficacy was reconfirmed in patients who underwent a 3-month chronic induction study. The system successfully detected all 763 induced arrhythmias and terminated 99.5% of them; after system modification, successful conversion was demonstrated in the 2 patients who initially had induced episodes requiring external defibrillation (1 lead revision; 1 reprogramming). All spontaneous episodes were terminated with an implantable-cardioverter defibrillator. Postshock VF redetection times were significantly shorter than initial detection times (4.5 +/- 1.8 seconds detection, 2.1 +/- 0.7 seconds redetection; p<0.0001). During an 8-month mean follow-up (range 1 to 31 months), 2 unwitnessed deaths were classified as sudden cardiac deaths, and 11 patients experienced a total of 12 complications, none of which was associated with the Cadence-Endotak combination.     

校园重访:反省台湾大学1980年代的校园规划

就 198 0年代《台大校园规划》的历史条件、形成脉络、主要内容与执行过程 ,讨论其结果与一些经验 ,并反省它的影响、限制与历史意义。 1980年代的台湾大学校园规划是台湾大学校方有意识地运用校园规划以管理校园成长的起点。在此分析其过程 ,总结其教训 ,不但对大学校园规划有积极意义 ,而且在规划理论与实务方面 ,对历史地面临快速发展的大机构 (institu tions) ① 、城市与区域所面对的挑战 ,也希望有一定程度的启发     

Sound field analysis and simulation for fluid machines

Fluid machines, such as pumps, fans, and internal combustion engines, are widely used in duct systems for air-conditioning, cooling, ventilating, heat releasing, and dust collecting. Vibration and noise will be created when the fluid machine works with fans at various rotating speeds. Noise problems associated with fan installation are a concern in fluid machines. Methods to analyze the sound field and simulation of fan installation are, therefore, important for the design to reduce the noise output from fluid machines. The sound field is simulated by using the boundary element method (BEM), which is a numerical technique to reduce the boundary integral equations using the fundamental solution and Green’s transfer functions, for sound field analysis in this paper. For the sound field analysis, the geometry of the fluid machines (the axial fan and centrifugal fan) and the acoustic properties are modeled in Beasy software based on the boundary element method technology. The 1/1 octave frequency band from 63 Hz to 8 kHz ranges are selected on sound field analysis. The sound pressure of the fan and the motor in each octave band are calculated by the parameters of rotating speed, flow volume, horse power and number of blades used. The results show that there is a high level sound pressure inside the housing of the axial fan due to the sound source located there. The higher sound pressure level is observed on both the inlet and outlet. The results for the centrifugal fan are the higher the frequency, the heavier energy that is found to radiate around the sound source.     

Methods for Locating Stray-Signal Sources in Anechoic Chambers

Two complementary numerically efficient frequency-domain methods for locating stray-signal sources in anechoic chambers are investigated and applied in combination to actual measurement data. Both methods use single-frequency near-field data collected on a planar surface and process them to reconstruct field values (images) elsewhere. The first method, which is based on the fact that the probe output satisfies the Helmholtz equation, uses plane waves to backpropagate the scan-plane data and is well suited for fast-Fourier-transform (FFT)-based rapid reconstruction of images on planar surfaces parallel to the scan plane. The second method uses the simple spherical-wave focusing technique and is flexible, in that, it can be used to generate images on either planar or nonplanar surfaces from the data collected on either planar or nonplanar surfaces. When data and image points are both located on a regular grid, the method can be implemented using the FFT-based fast convolution technique. Both methods include a spatial filter for isolating selected plane-wave spectrum components. The two methods are used in combination to successfully locate the strong multiple-bounce stray signals that degrade the quiet zone of a near-field bistatic radar cross-section facility. Subsequent scan data confirm that the suppression of these stray signals indeed substantially improves the quality of the quiet zone. The spherical-focusing method is also used to evaluate the effectiveness of the various absorber configurations applied to selected edges of the reflector to control edge-diffracted fields. It is shown that the reduction of the edge-diffracted fields further improves the quiet zone.     

Rayleigh scattering limits for low-level bidirectional reflectance distribution function measurements: corrigendum.

In previous research [C. C. Asmail et al. Appl. Opt. 33, 6084-6091 (1994)] an estimate was given of the low-level bidirectional reflectance distribution function (BRDF) limit due to Rayleigh scattering from the air molecules within the detector field of view. Although the underlying model was correct, a fault in the derivation led to a conclusion that contains an erroneous angular factor. A cosine factor in the equivalent BRDF derived by Asmail et al. [Appl. Opt. 33, 6084-6091 (1994)], which was considered unphysical in that treatment, is incorrect and can obscure the correction in certain circumstances. The treatment below calculates the scattered flux from the gas molecules in the field of view and compares it with the flux scattered from a sample in the same incident beam.     

A factor analysis based selection process for predicting successful university color guard club members

The purpose of this paper is to determine how to place students in the most appropriate club, to save training time and expenses, and maximize club performance. To this end, this research utilizes the example of the color guard club at Chienkuo Technology University (CTU). First, the authors researched the characteristics needed to be a color guard member. Second, a series of tests for measuring these characteristics was designed. Third, the authors administered the tests to all the club members and recorded the results. Fourth, after the club members had received one year of training, the authors ran regression analysis by using data from the tests of those who successfully passed the training. From this, the authors obtained a regression model. The authors then ran logistic regression analysis and discriminant analysis on the test data of all initial color guard club members, including those who eventually passed the training and those who eventually withdrew, to establish screening norms. Last, using factor analysis, the authors found the latent factors. These factors, along with the screening norms, can serve as a foundation for future selection of color guard members. This process of selecting club members scientifically may be adopted by other clubs in order to match students and clubs most effectively.     

Adaptive video coding control for real-time H.264/AVC encoder

In this paper, we present a new adaptive video coding control for real-time H.264/AVC encoding system. The main techniques include: (1) the initial quantization parameter (QP) decision scheme is based on Laplacian of Gaussian (LoG) operators; (2) the MB-level QP calculation is based on the spatio-temporal correlation, in which the computation is less than the quadratic model used by H.264/AVC; (3) the adaptive GOP structure is proposed, in which the I-frame is adaptively replaced by an enhancement P-frame to improve the coding efficiency; (4) the scene change is detected with the complexity of adjacent inter-frames and the appropriate QP is re-calculated for the scene-change frame. The proposed algorithm is not only to save the computational complexity but also to improve coding quality. Compared to the JM12.4 reference under various sequences testing, the proposed algorithm can decrease coding time by 64.5% and improve PSNR by 1.52 dB while keeping the same bit-rate.