Supercritical fluid extraction of oil from potato chips: Two scale comparison and mathematical modeling

Oil was extracted from fried chipped potatoes using supercritical carbon dioxide. The goals of the study were to determine the effect of process parameters on the extraction, explore the scalability of the process, and determine useful kinetic parameters. Extraction conditions range 27.6–41.4 MPa (4000–6000 PSI), 35–80 °C and solvent flow rate of 0.5–5.0 g CO₂/min. Up to 100% of the oil was recovered from the potato chips at the highest pressure and temperature conditions. Two process conditions were chosen for comparison of performance with a larger scale (1:5) system, maintaining the same CO₂ flow rate to feed mass ratio. Good agreement between scales was seen at the higher pressure and temperature settings. Kinetic parameters, calculated using a literature model, indicated that, as expected, the extraction is limited by internal diffusion.     

Fault Tolerant Suffix Trees

Classical algorithms and data structures assume that the underlying memory is reliable, and the data remain safe during or after processing. However, the assumption is perilous as several studies have shown that large and inexpensive memories are vulnerable to bit flips. Thus, the correctness of output of a classical algorithm can be threatened by a few memory faults. Fault tolerant data structures and resilient algorithms are developed to tolerate a limited number of faults and provide a correct output based on the uncorrupted part of the data. Suf- fix tree is one of the important data structures that has widespread applications including substring search, super string problem and data compression. The fault tolerant version of the suffix tree presented in the literature uses complex techniques of encodable and decodable error-correcting codes, blocked data structures and fault-resistant tries. In this work, we use the natural approach of data replication to develop a fault tolerant suffix tree based on the faulty memory random access machine model. The proposed data structure stores copies of the indices to sustain memory faults injected by an adversary. We develop a resilient version of the Ukkonen’s algorithm for constructing the fault tolerant suffix tree and derive an upper bound on the number of corrupt suffixes.     

Genome-Wide Identification of Aquaporin Genes in Adzuki Bean (Vigna angularis) and Expression Analysis under Drought Stress

The adzuki bean Vigna angularis (Wild.) is an important leguminous crop cultivated mainly for food purposes in Asian countries; it represents a source of carbohydrates, digestible proteins, minerals, and vitamins. Aquaporins (AQPs) are crucial membrane proteins involved in the transmembrane diffusion of water and small solutes in all living organisms, including plants. In this study, we used the whole genome sequence of the adzuki bean for in silico analysis to comprehensively identify 40 Vigna angularis aquaporin (VaAQP) genes and reveal how these plants react to drought stress. VaAQPs were compared with AQPs from other closely-related leguminous plants, and the results showed that mustard (Brassica rapa) (59), barrel medic (Medicago truncatula) (46), soybean (Glycine max) (66), and common bean (Phaseolus vulgaris L.) (41) had more AQP genes. Phylogenetic analysis revealed that forty VaAQPs belong to five subfamilies, with the VaPIPs (fifteen) subfamily the largest, followed by the VaNIPs (ten), VaTIPs (ten), VaSIPs (three), and VaXIPs (two) subfamilies. Furthermore, all AQP subcellular locations were found at the plasma membrane, and intron–exon analysis revealed a relationship between the intron number and gene expression, duplication, evolution, and diversity. Among the six motifs identified, motifs one, two, five, and six were prevalent in VaTIP, VaNIP, VaPIP, and VaXIP, while motifs one, three, and four were not observed in VaPIP1-3 and VaPIP1-4. Under drought stress, two of the VaAQPs (VaPIP2-1 and VaPIP2-5) showed significantly higher expression in the root tissue while the other two genes (VaPIP1-1 and VaPIP1-7) displayed variable expression in leaf tissue. This finding revealed that the selected VaAQPs might have unique molecular functions linked with the uptake of water under drought stress or in the exertion of osmoregulation to transport particular substrates rather than water to protect plants from drought. This study presents the first thorough investigation of VaAQPs in adzuki beans, and it reveals the transport mechanisms and related physiological processes that may be utilized for the development of drought-tolerant adzuki bean cultivars.     

Improved process monitoring using the CUSUM and EWMA-based multiscale PCA fault detection framework

Process monitoring techniques are of paramount importance in the chemical industry to improve both the product quality and plant safety. Small or incipient irregularities may lead to severe degradation in complex chemical processes, and the conventional process monitoring techniques cannot detect these irregularities. In this study to improve the performance of monitoring, an online multiscale fault detection approach is proposed by integrating multiscale principal component analysis (MSPCA) with cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control charts. The new Hotelling's T² and square prediction error (SPE) based fault detection indices are proposed to detect the incipient irregularities in the process data. The performance of the proposed fault detection methods was tested for simulated data obtained from the CSTR system and compared to that of conventional PCA and MSPCA based methods. The results demonstrate that the proposed EWMA based MSPCA fault detection method was successful in detecting the faults. Moreover, a comparative study shows that the SPE-EWMA monitoring index exhibits a better performance with lower values of missed detections ranging from 0% to 0.80% and false alarms ranging from 0% to 21.20%.     

Pilot-Scale Verification and Analysis of Iron Release Flux Model

An original model by Mutoti in 2003 was developed mathematically, and empirically, to predict the increase in total iron concentration in distribution systems. This model, referred to as a flux model, relates the increase in iron concentration in a reach of unlined or galvanized iron pipe to the surface area of the pipe in contact with the water. A flux term, defined with a dimension of mass per area per time was used. The effects of water chemistry, pipe material and hydraulic conditions were incorporated into the flux term. This paper describes the verification of the flux model using independent pilot data obtained with variable water quality under worst case, laminar flow conditions. The original model accurately predicted iron release for this independent verification data, with an overall R2 of 0.80. For laminar flow conditions, the increase in iron concentration is proportional to the flux and the hydraulic residence time, and is inversely proportional to the pipe diameter.     

Ring rupture strength and hardness of sintered hot-forged 1.5Mo alloyed carbon steels

The effect of fractional density and height-to-diameter ratio (aspect ratio) on radial crushing strength for sintered hot-upsetted Fe–0.8%C as well as Fe–0.8%C–0.5%Mo powder metallurgy rings were investigated. Rings of predetermined geometry were machined from the hot deformed preforms of different initial densities. It was found that increasing density of the rings had increased the radial crushing strength irrespective of compositions. Further, it was observed that the hardness values were continuously increasing with increasing fractional density. Increasing the aspect ratio of preforms substantially increased the hardness values for any theoretical density attained. It was also observed from fractographs that majority of the rings crushed in a brittle manner.     

Switchable circular disk antenna for RCS and mobile communications applications

In this paper, we describe the operation of a low profile, 3 mm deep, circular disk antenna which requires a small ground plane, and incorporates a shorting bar which can be rotated. The position of the shorting bar determines the return loss and radiation characteristics of the antenna element. In one mode at 2.34 GHz the antenna exhibits a return loss of better than -25 dB, 5 dBi gain, and a conical/monopole beam pattern suitable for radar tracking/mobile communications applications. When the short circuit is positioned at 90 degrees the return loss at 3.52 GHz becomes -18 dB, 7 dBi gain, and the antenna exhibits normal linear polarized broadside cosine radiation characteristics. In addition when the short circuit is positioned at zero degrees at 3.52 GHz the antenna gives -1 dB return loss and by reciprocity will act as a reflector to incoming energy. Theoretical results are provided in support of the experimental results observed and are used to explain the operating mechanisms of the antenna.     

Isolation and identification of Aeromonas species from human stools

One thousand and three diarrhoeal stool samples were processed in our laboratory during the period 1996/1997 for the presence of enteric pathogens especially Aeromonas spp., which has emerged as a new agent causing diarrhoea. Ampicillin sheep blood agar was found to be the best medium for the isolation of Aeromonas spp. from stool specimens. Enteric pathogens were found in 200 (20%) stools, of which Aeromonas spp. was the second commonest pathogen isolated amounting to 21% of isolates. This study clearly indicates that Aeromonas spp. must be looked for in every diarrhoeal stool samples, specially in children below 10 years of age. Isolation and identification is cost effective and easy, if the given protocol is observed.     

Robust static allocation of resources for independent tasks under makespan and dollar cost constraints

Heterogeneous computing (HC) systems composed of interconnected machines with varied computational capabilities often operate in environments where there may be inaccuracies in the estimation of task execution times. Makespan (defined as the completion time for an entire set of tasks) is often the performance feature that needs to be optimized in such systems. Resource allocation is typically performed based on estimates of the computation time of each task on each class of machines. Hence, it is important that makespan be robust against errors in computation time estimates. In this research, the problem of finding a static mapping of tasks to maximize the robustness of makespan against the errors in task execution time estimates given an overall makespan constraint is studied. Two variations of this basic problem are considered: (1) where there is a given, fixed set of machines, (2) where an HC system is to be constructed from a set of machines within a dollar cost constraint. Six heuristic techniques for each of these variations of the problem are presented and evaluated.     

将无线网络技术的性能再提升

文章介绍了业界正发展的一种超越时分或频分复用限制的多进多出(MIMO)无线局域网技术新概念,它在速度和容量上实现量的飞跃,甚至要接近有线网络技术。