Study of Deformation Phenomena in TRIP/TWIP Steels by Acoustic Emission and Scanning Electron Microscopy

Modern metastable steels with TRIP/TWIP effects have a unique set of physical-mechanical properties. They combine both high-strength and high-plasticity characteristics, which is governed by processes activated during deformation, namely, twinning, the formation of stacking faults, and martensitic transformations. To study the behavior of these phenomena in CrMnNi TRIP/TWIP steels and stainless CrNiMo steel, which does not have these effects in the temperature range under study, we used the method of acoustic emission and modern methods of signal processing, including the cluster analysis of spectral-density functions. The results of this study have been compared with a detailed microstructural analysis performed with a scanning electron microscope using electron backscatter diffraction (EBSD).     

Genetic Variation in Jasmonic Acid- and Spider Mite-Induced Plant Volatile Emission of Cucumber Accessions and Attraction of the Predator <Emphasis Type="Italic">Phytoseiulus persimilis</Emphasis>

Cucumber plants (Cucumis sativus L.) respond to spider–mite (Tetranychus urticae) damage with the release of specific volatiles that are exploited by predatory mites, the natural enemies of the spider mites, to locate their prey. The production of volatiles also can be induced by exposing plants to the plant hormone jasmonic acid. We analyzed volatile emissions from 15 cucumber accessions upon herbivory by spider mites and upon exposure to jasmonic acid using gas chromatography—mass spectrometry. Upon induction, cucumber plants emitted over 24 different compounds, and the blend of induced volatiles consisted predominantly of terpenoids. The total amount of volatiles was higher in plants treated with jasmonic acid than in those infested with spider mites, with (E)-4,8-dimethyl-1,3,7-nonatriene, (E,E)-α-farnesene, and (E)-β-ocimene as the most abundant compounds in all accessions in both treatments. Significant variation among the accessions was found for the 24 major volatile compounds. The accessions differed strongly in total amount of volatiles emitted, and displayed very different odor profiles. Principal component analysis performed on the relative quantities of particular compounds within the blend revealed clusters of highly correlated volatiles, which is suggestive of common metabolic pathways. A number of cucumber accessions also were tested for their attractiveness to Phytoseiulus persimilis, a specialist predator of spider mites. Differences in the attraction of predatory mites by the various accessions correlated to differences in the individual chemical profiles of these accessions. The presence of genetic variation in induced plant volatile emission in cucumber shows that it is possible to breed for cucumber varieties that are more attractive to predatory mites and other biological control agents.     

Feed water pretreatment for desalination plants

Effective membrane pretreatment is a crucial requirement for trouble free and cost effective RO desalination. Pretreatment construction costs are significant and may reach as much as 10%-20% of the total desalination plant capital costs. This paper presents a general review of the central factors involved in assessing raw water quality. The main foulant categories are described and the various unit operations commonly applied are reviewed. Pretreatment aspects of desalination offer fertile grounds for advancing desalination technologies. Promising research directions are highlighted.     

Recombinant tropomyosin from Penaeus aztecus (rPen a 1) for measurement of specific immunoglobulin E antibodies relevant in food allergy to crustaceans and other invertebrates

Immunoglobulin E (IgE)-mediated food allergy to crustaceans and mollusks is relatively common and affected individuals typically react to a range of different species. The only known major allergen of shrimp was first described over 20 years ago and later identified as the muscle protein tropomyosin. This protein may be useful as a defined and relevant diagnostic marker for allergic sensitization to invertebrate foods. In order to generate an assay reagent suitable for this purpose, tropomyosin from the shrimp Penaeus aztecus (Pen a 1) was produced as a recombinant protein in Escherichia coli and characterized with respect to IgE antibody binding properties in comparison to natural shrimp tropomyosin. Hexahistidine-tagged rPen a 1 accumulated as a predominantly soluble protein in the E. coli expression host and a two-step chromatographic procedure provided a high yield of pure and homogeneous protein. rPen a 1 displayed chromatographic and folding characteristics similar to those of purified natural shrimp tropomyosin. Serum preincubation with serial protein dilutions revealed similar capacity of recombinant and natural tropomyosin to compete with immobilized shrimp extract for IgE binding. rPen a 1 was further shown to extensively and specifically compete for IgE binding to extracts of other crustacean species, house dust mite and German cockroach.     

A novel method for chip formation analyses in deep hole drilling with small diameters

Recent trends of downsizing and miniaturization of components, e.g. in the automotive industry for the manufacturing of fuel injectors or in the medical industry for the production of bone screws or surgical instruments, increase the importance of mechanical deep hole drilling with small diameters. Unfortunately, there are still some open challenges regarding this process. In addition to the unfavorable ratio of the cutting edge rounding to the achievable feed rates and undeformed chip thicknesses which results in significant mechanical tool loads, the control of the chip formation and the removal constitutes a major difficulty. The slender tool dimensions, especially the small cross sections of the chip flutes, necessitate a favorable chip formation to achieve the required process safety and productivity. Therefore, analyses of the chip formation, when machining difficult-to-cut materials provide the means for an effective process design. This analysis, however, is particularly difficult due to the closed operating zone. Quick-stop devices used for the chip formation analyses so far are limited in the tool diameter respectively the revolution speed. Furthermore the informative value is limited, because a quick-stop test takes a significant time to stop and thus the instantaneous cutting conditions during the tool retraction are altered. To overcome these restrictions, a new method for the analysis of the chip formation in small diameter deep hole drilling is presented in this paper. It is based on the utilization of a high-speed camera and tailored material samples. The experimental set-up and the results of first analyses conducted under minimum quantity lubrication are presented. The chip formation process is analyzed for the single-lip gun drilling of the nickel-based alloy Inconel718 and the bainitic steel 20MnCrMo7.     

Neutrinos from photo-hadronic interactions in Pks2155-304

The high-peaked BL Lac object Pks2155-304 shows high variability at multiwavelengths, i.e. from optical up to TeV energies. A giant flare of around 1 h at X-ray and TeV energies was observed in 2006 [1]. In this context, it is essential to understand the physical processes in terms of the primary spectrum and the radiation emitted, since high-energy emission can arise in both leptonic and hadronic processes. In this contribution, we investigate the possibility of neutrino production in photo-hadronic interactions. In particular, we predict a direct correlation between optical and TeV energies at sufficiently high optical radiation fields. We show that in the blazar Pks2155-304, the optical emission in the low-state is sufficient to lead to photo-hadronic interactions and therefore to the production of high-energy photons.     

Grafting of Maleic Anhydride Copolymers onto Cellulose Acetate and Methyl Cellulose

A high level of control over grafting reactions onto cellulose derivatives was achieved by an acyl transfer reaction mechanism. Ethylene/maleic anhydride copolymer (EMA) and styrene/maleic anhydride copolymer (SMA) were grafted onto cellulose acetate (CA) and methyl cellulose (MC) in a simple and effective way under homogeneous reaction conditions. While pyridine, a commonly used catalyst for the reaction of an anhydride with an alcohol to form an ester, gave an inconveniently long reaction time, N-methylimidazole (NMID) and 4-(N,N-dimethylamino)pyridine (DMAP) were found to increase greatly the rate of esterification.     

Tablet Adoption with Smart School Website Technology

Teachers play a key role in adoption of technologies for classroom use. This study surveyed teachers regarding their intention to use tablet technology to interact with students and other teachers through smart school websites technology. The Unified Theory of Acceptance and Use of Technology (UTAUT) served as the theoretical framework for this study, which was then augmented with context-specific determinants of adoption that captured teachers’ perceptions of the effects of technology on interactions with students and peers. The results showed no resistance among teachers with regard to trying different ways of working with tablets to achieve better learning, unlike other studies using the UTAUT constructs that have found negative reactions to implementing new technologies in the workplace. This is a crucial finding, since teacher appraisals affect the ways in which this technology can be employed to foster learning through technology facilitated interactions.     

Phonological universals constrain the processing of nonspeech stimuli.

Domain-specific systems are hypothetically specialized with respect to the outputs they compute and the inputs they allow (Fodor, 1983). Here, we examine whether these 2 conditions for specialization are dissociable. An initial experiment suggests that English speakers could extend a putatively universal phonological restriction to inputs identified as nonspeech. A subsequent comparison of English and Russian participants indicates that the processing of nonspeech inputs is modulated by linguistic experience. Striking, qualitative differences between English and Russian participants suggest that they rely on linguistic principles, both universal and language-particular, rather than generic auditory processing strategies. Thus, the computation of idiosyncratic linguistic outputs is apparently not restricted to speech inputs. This conclusion presents various challenges to both domain-specific and domain-general accounts of cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

SULFUR FILTER BY INTERMETALLIC MEDIA

ABSTRACT

Two types of filter are developed. One is for the removal of sulfur compounds in petroleum and its derived products. The other is for upgrading, which is to lower the amount of asphaltene. Although research in selectivity and life cycle estimation of intermetallic media is still continuing, the mechanisms behind this technology are based upon the concept of nanotechnology and the principle of membrane mimetic chemistry.