The structure and ultrastructure of the egg capsule of Brachyptera risi (Plecoptera,Nemouroidea, Taeniopterygidae) with some remarks concerning choriogenesis

The organization of the egg capsule of the euholognathan stonefly, which represents the family Taeniopterygidae (Nemuroidea) was investigated using light and electron microscopy techniques. The presence of a complex, multilayered egg capsule, composed of a vitelline envelope, multilayered chorion, and extrachorion is described. The morphology of the eggshell of Brachyptera risi was compared with that of euholognthan and systellognathan egg coverings and the ground plan of the egg capsule in Plecoptera was discussed. Microsc. Res. Tech. 78:180–186, 2015. © 2014 Wiley Periodicals, Inc.     

Synthesis and evaluation of swelling kinetics of electric field responsive poly(vinyl alcohol)‐g‐polyacrylic acid/OMNT nanocomposite hydrogels

Novel electro‐responsive nanocomposite hydrogels were prepared by the radical graft polymerization reaction of partially neutralized acrylic acid on poly(vinyl alcohol) and organically modified MMT nanoclay (OMMT) using glutaraldehyde as a crosslinker and potassium initiator. The structures of the hydrogels were confirmed by using Fourier transform infrared, X‐ray diffraction, and scanning electron microscopy study. The nanocomposite hydrogels were characterized by evaluating such molecular weight between crosslinks, (Mc) crosslinking density (ρ), and mesh size (ξ). The effects of various parameters on the swelling behavior of the hydrogels were studied. The thermogravimetric analysis indicated that introduction of clay resulted in an increase in thermal stability. Finally, the electric stimuli responsive measurement indicates the bending of hydrogel toward the cathode in an aqueous solution of NaCl. POLYM. COMPOS., 36:34–41, 2015. © 2014 Society of Plastics Engineers     

Catastrophic Failures in Power Systems: Causes, Analyses, and Countermeasures

Catastrophic failures of power systems are phenomena which occur with some regularity throughout the world. It is recognized that these cannot be prevented, although with the use of newer developments in power engineering, in communication systems, and in computer engineering it would be possible to reduce their frequency and their impact on society. Analyses of many blackouts point to some salient features which are common to most such events: power systems under stress because of high load levels or outages of important facilities, some initiating event-usually a fault, often followed by cascading effects due to unwanted operation of some protection systems. In particular, the role of hidden failures (HFs) in protection systems in propagating power system disturbances has become clearer with some of the recent research reported in the literature. This paper explores further the issue of HFs of protection systems and possible countermeasures. Regarding the countermeasures, adapting the protection systems so that they would change their operational logic from OR to a VOTING protocol has been discussed in the literature, and is well within the capability of present technology. Other hardware solutions, such as "Hidden Failure Monitoring and Protection Systems," have also been discussed in the literature. Most of these countermeasures will require intensive use of communication networks. Communication infrastructure will be utilized for real-time data transfer, as well as for slower speed data gathering tasks related to the condition of the power system. In this paper, we concentrate on the communication facilities and their applications for providing countermeasures against catastrophic failures of power systems.     

Storing and retrieving software components: a refinement basedsystem

Software libraries are repositories which contain software components; as such, they represent a precious resource for the software engineer. As software libraries grow in size, it becomes increasingly difficult to maintain adequate precision and recall with informal retrieval algorithms. In this paper, we discuss the design and implementation of a storage and retrieval structure for software components that is based on formal specifications and on the refinement ordering between specifications     

Effects of electrodeposited zinc coating on the formability of drawing-quality aluminum-killed sheet steel

Although sheet formability depends significantly on the properties of the base metal, surface coatings used for corrosion protection can affect the friction at the tool/sheet interface and, therefore, influence the amount of deformation. In an effort to better understand the effects of surface coatings on formability, limiting dome height testing was done on samples of drawing- quality aluminum- killed sheet steel with laboratory- produced electrodeposited zinc coatings of different characteristics. The results showed that the formability of zinc- coated products was reduced compared to the uncoated steel in all strain states. It was also shown that zinc coating crystallographic texture strongly influences sheet forming behavior and may be as important a parameter as surface roughness in friction characterization. The material in this article is intended for general information only. Any use of this material in relation to any specific application should be based on independent examination and verification of its unrestricted availability for such use and a determination of suitability for the application by professionally qualified personnel. No license under any USX Corporation patents or other proprietary interest is implied by the publication of this paper. Those making use of or relying upon the material assume all risks and liability arising from such use or reliance.     

Outage Performance of Dual-Hop AF Relay Channels with Co-Channel Interferences over Rayleigh Fading

This paper studies the outage performance of a dual-hop amplify-and-forward (AF) relay fading channel in an interference-limited environment. The relay and destination nodes are corrupted by multiple co-channel Rayleigh interferences. New exact closed-form expressions for the outage probability for channel-state-information (CSI)—assisted relay, in which gain is dependent on previous hop CSI and interference, are derived. Monte Carlo simulations are performed to verify the obtained theoretical results. For the cases where the number of interferers at the relay and the destination node is equal, we derive novel expressions for outage probability upper and lower bounds.     

Analysis of Acoustic Emission energy release during static fatigue tests at intermediate temperatures on Ceramic Matrix Composites: Towards rupture time prediction

Ceramic Matrix Composites (CMCs) such as woven SiC_f/[Si–B–C] are used in aeronautical engines. Expected lifetimes in service conditions are tens of thousands of hours and therefore unattainable in laboratory tests. This paper shows the potential of Acoustic Emission (AE) based approach to lifetime prediction of CMCs. The energy of AE events is used as a measure of stress-induced damage during static fatigue at intermediate temperatures. The energy released by sources was determined from the signal energy received by two sensors, the effects of attenuation due to propagation distance were eliminated. A method for real-time analysis of energy release has been developed. It allows the identification of a characteristic time at 55% of the measured rupture time. This characteristic time reflects a local critical behavior described by the Benioff law and it indicates a second damage phase when subcritical crack growth in fibers is predominant.     

Refolding of biotech therapeutic proteins expressed in bacteria: review

The efficiency of the protein refolding process lies in identification of the optimal conditions. However, a number of challenges need to be overcome to achieve this. This review first describes the protein refolding process that is utilized presently for production of protein therapeutics. Next, it discusses the various shortcomings that exist with respect to the present approach. The focus of the paper is on presentation of the significant advancements that have been made in the past decade in the various aspects of protein folding, including use of bioinformatics, mechanistic modeling, analytical monitoring, process optimization, use of additives, high throughput development, on‐column refolding, Quality by Design (QbD), Process Analytical Technology (PAT), and process intensification. Finally, an approach is proposed that incorporates the best practices that have been identified in the various areas. The paper is expected to be of interest to those in academia and industry working in the area of protein refolding. © 2013 Society of Chemical Industry.