Instruction Set Extensions for Matrix Decompositions on Software Defined Radio Architectures

Emerging wireless applications consistently demand higher data rates. Unfortunately, it is challenging to achieve high data rates within the limited amount of available frequency spectrum. Hence, enhanced spectral efficiency and link reliability within the available frequency spectrum are of the utmost importance in current and next generation wireless protocols. To attain high spectral efficiency and link reliability, wireless protocols employ increasingly complex 2-dimensional techniques that involve computationally-intensive matrix operations. Multiple-Input Multiple-Output (MIMO) communication is an example of a promising technique employed by wireless protocols to deliver higher data rates at the cost of increased algorithmic complexity. Application Specific Integrated Circuits (ASICs) have traditionally been used to implement compute-intensive wireless protocols. The wireless industry has been gradually moving towards an alternative programmable platform called Software Defined Radio (SDR) due to its significant benefits, such as reduced development costs, and accelerated time-to-market. The computationally-intensive matrix operations used in current and next generation wireless protocols are extremely expensive to implement in SDR platforms with conventional Digital Signal Processor (DSP) instruction sets. Hence there is a need for novel instructions, hardware designs and algorithm enhancements to enable higher spectral efficiency on SDR platforms. In this paper, we propose Single Instruction Multiple Data (SIMD) CoOrdinate Rotation DIgital Computer (CORDIC) instruction set extensions with CORDIC hardware support to speedup computationally-intensive matrix decomposition algorithms. The CORDIC instruction set extensions have been implemented on the Sandbridge Sandblaster SB3000 SDR platform and evaluated on conventional algorithms used for decomposing a closed loop 4-by-4 Worldwide Interoperability for Microwave Access (WiMAX) MIMO channel into independent Single-Input Single-Output (SISO) channels. Our experimental results on the closed-loop MIMO channel decomposition using CORDIC instructions demonstrate more than 6x speedup over a Sandblaster baseline implementation that uses state-of-the-art SIMD DSP instructions. The CORDIC instructions also provide similar numerical accuracy when compared to the baseline implementation. The techniques we propose in this paper are also applicable to other SDR and embedded processor architectures.     

Growth of the Dysprosium–Barium–Copper Oxide Superconductor Nanoclusters in Biopolymer Gels

Clusters of DyBa₂Cu₃O_7?y high T_C type II nanosuperconductor were prepared by sol–gel method in the presence of biopolymer chitosan. At the first step, the precursor and biopolymer were aggregated into amorphous matrix and then hydrogels were formed by thermogelling. Nucleation and growth of discrete nanoparticles is controlled by the biopolymer gel owing to retention of the fibrous nature of the chitosan at high temperatures up to 500?°C. After heating to 900?°C and complete decomposition of BaCO₃, nanoparticles of DyBa₂Cu₃O_7?y superconductor with diameter of 10–20?nm in the form of nanoclusters are prepared. Critical temperature (T_c) of the nanoparticles was found to be above 83?K. Characterizations of specimens were performed using scanning electron microscopy and transmission electron microscopy, supported by other techniques including XRD diffraction, energy dispersive X-ray, FT-IR spectrum and magnetic susceptibility measurements.     

常温下双循环厌氧反应器处理中药废水的性能及污泥特性研究

分析了双循环(DC)厌氧反应器在常温下处理中药废水的可行性,并对常温下DC反应器内颗粒污泥特性进行了研究。结果表明,当温度由30℃降为20℃时,DC厌氧反应器出水COD可维持在300mg/L以下,去除率为95%左右;出水挥发性脂肪酸(VFA)的质量浓度虽由原来的66.2mg/L增大到256.2mg/L,但并未出现VFA的显著累积,产气量为仍为12~14L/d。颗粒污泥胞外聚合物(EPS)的组分均以蛋白和多糖为主,同时辅酶F420的吸收峰非常显著,表明常温下反应器内颗粒污泥的产甲烷活性良好。但温度的降低造成了颗粒污泥中铁与镁离子含量的降低,同时影响了颗粒污泥中的微生物群落,使索氏甲烷丝菌成为优势菌属。     

CSTR反应器抗扰动能力的稳态模拟与动态模拟

本文以环氧丙烷PO水合法制1,2-丙二醇为例,对CSTR抗扰动能力进行了稳态及动态模拟的对比研究,分析了进料温度扰动对PO转化率的影响。结果表明:若进料温度升高,稳态与动态模拟结果一致,PO转化率增幅较小;当进料温度降温幅度4.00K时,稳态与动态模拟结果一致,PO转化率减幅较小;当进料温度降温幅度≥4.00K但高于熄火温度时,稳态模拟结果显示CSTR仍处于较高PO转化率状态,转化率变化较小,但动态模拟结果表明此时CSTR已从高PO转化率状态跌至低PO转化率状态,稳态与动态模拟结果不符;当进料温度降至熄火温度以下时,稳态与动态模拟结果一致,CSTR均从高PO转化率状态跌至低PO转化率状态。通过对比可知,动态模拟比稳态模拟能更真实地反映CSTR的抗扰动能力。     

Decomposition of energetic chemicals contaminated with iron or stainless steel

Contamination of chemicals or reaction mixtures with iron or stainless steel is likely to take place during chemical processing. If energetic and thermally unstable chemicals are involved in a manufacturing process, contamination with iron or stainless steel can impact the decomposition characteristics of these chemicals and, subsequently, the safety of the processes, and should be investigated. The goal of this project was to undertake a systematic approach to study the impact of iron or stainless steel contamination on the decomposition characteristics of different chemical classes. Differential scanning calorimetry (DSC) was used to study the decomposition reaction by testing each chemical pure, and in mixtures with iron and stainless steel. The following classes of energetic chemicals were investigated: nitrobenzenes, tetrazoles, hydrazines, hydroxylamines and oximes, sulfonic acid derivatives and monomers. The following non-energetic groups were investigated for contributing effects: halogens, hydroxyls, amines, amides, nitriles, sulfonic acid esters, carbonyl halides and salts of hydrochloric acid. Based on the results obtained, conclusions were drawn regarding the sensitivity of the decomposition reaction to contamination with iron and stainless steel for the chemical classes listed above. It was demonstrated that the most sensitive classes are hydrazines and hydroxylamines/oximes. Contamination of these chemicals with iron or stainless steel not only destabilizes them, leading to decomposition at significantly lower temperatures, but also sometimes causes increased severity of the decomposition. The sensitivity of nitrobenzenes to contamination with iron or stainless steel depended upon the presence of other contributing groups: the presence of such groups as acid chlorides or chlorine/fluorine significantly increased the effect of contamination on decomposition characteristics of nitrobenzenes. The decomposition of sulfonic acid derivatives and tetrazoles was not impacted by presence of iron or stainless steel.     

Heat tolerance of Salmonella enterica serovars Agona, Enteritidis, and Typhimurium in peanut butter

Recent large foodborne outbreaks caused by Salmonella enterica serovars have been associated with consumption of foods with high fat content and reduced water activity, even though their ingredients usually undergo pasteurization. The present study was focused on the heat tolerance of Salmonella enterica serovars Agona, Enteritidis, and Typhimurium in peanut butter. The Salmonella serovars in the peanut butter were resistant to heat, and even at a temperature as high as 90 degrees C only 3.2-log reduction in CFU was observed. The obtained thermal inactivation curves were upwardly concave, indicating rapid death at the beginning (10 min) followed by lower death rates and an asymptotic tail. The curves fitted the nonlinear Weibull model with beta parameters < 1, indicating that the remaining cells have a lower probability of dying. beta at 70 degrees C (0.40 +/- 0.04) was significantly lower than beta at 80 degrees C (0.73 +/- 0.19) and 90 degrees C (0.69 +/- 0.17). Very little decrease in the viable population (less than 2-log decrease) was noted in cultures that were exposed to a second thermal treatment. Peanut butter is a highly concentrated colloidal suspension of lipid and water in a peanut meal phase. We hypothesized that differences in the local environments of the bacteria, with respect to fat content or water activity, explained the observed distribution and high portion of surviving cells (0.1%, independent of the initial cell number). These results demonstrate that thermal treatments are inadequate to consistently destroy Salmonella in highly contaminated peanut butter and that the pasteurization process cannot be improved significantly by longer treatment or higher temperatures.     

A study on UV-protection property of poly(vinyl alcohol)-montmorillonite composite nanofibers

The aim of this research is to investigate the possibility of barrier effect of poly(vinyl alcohol) (PVA)/montmorillonite (MMT) nanofiber, against the UV radiation in different electrospinning situations. For this purpose, nanofibers with different weight ratio of PVA and nanoclay (MMT) were electrospun under different circumstances, and the amount of protect that is created by the nanofiber web against UV radiation by examining the rate of degradation of methylene blue dye that was protected by the same web was estimated. The UV-vis spectrometry was used for the analysis of methylene blue color. In order to investigate the morphology and miscibility of PVA-MMT composite nanofiber, X-ray diffraction, scanning election microscope, and Fourier transform infrared spectrometer have been used. Thermal gravimetric analysis is used to investigate and explore how nanofibers behave against heat.     

β-Amyloid Targeting with Two-Dimensional Covalent Organic Frameworks: Multi-Scale In-Silico Dissection of Nano-Biointerface

Cytotoxic aggregation of misfolded β-amyloid (Aβ) proteins is the main culprit suspected to be behind the development of Alzheimer's disease (AD). In this study, Aβ interactions with the novel two-dimensional (2D) covalent organic frameworks (COFs) as therapeutic options for avoiding β-amyloid aggregation have been investigated. The results from multi-scale atomistic simulations suggest that amine-functionalized COFs with a large surface area (more than 1000 m²/gr) have the potential to prevent Aβ aggregation. Gibb's free energy analysis confirmed that COFs could prevent protofibril self-assembly in addition to inhibiting β-amyloid aggregation. Additionally, it was observed that the amine functional group and high contact area could improve the inhibitory effect of COFs on Aβ aggregation and enhance the diffusivity of COFs through the blood-brain barrier (BBB). In addition, microsecond coarse-grained (CG) simulations with three hundred amyloids reveal that the presence of COFs creates instability in the structure of amyloids and consequently prevents the fibrillation. These results suggest promising applications of engineered COFs in the treatment of AD and provide a new perspective on future experimental research.     

半密闭灭弧腔室内电弧运动特性的三维仿真和实验

在配网线路防雷中,利用多个半密闭灭弧腔室串联将长空气间隙电弧分段淬灭的多腔室灭弧结构因其优异的灭弧性能,受到学者的广泛关注.在应用于配网线路雷电防护时,多腔室灭弧结构中的气体间隙被击穿后,冲击电弧在半密闭灭弧腔室内的运动特性直接影响该结构的灭弧性能.为了研究冲击电弧在灭弧腔室内的运动特性,该文将气流场、流体传热场、电磁...