Experimental Characterisation of GLass Aluminum REinforced (GLARE™) laminates

Fibre metal laminates such as GLARE™ have found promising application in the aerospace industry. These laminates were developed at the structures and materials laboratory of Delft University of Technology, Netherlands. GLARE™ is a material belonging to the family of Fibre Metal Laminates consisting of thin aluminum layers bonded with unidirectional S2-Glass fibres with an adhesive. Aluminum and S2-Glass when combined as a hybrid material can provide best features of the both metals and composites. These materials have excellent fatigue, impact and damage tolerance characteristics and a lower density compared to aluminum. GLARE™ has found major application in front and aft upper fuselage, leading edges of empennages of advanced civil aircrafts like A380. This document looks into the evaluation of two configuration of GLARE™ for its mechanical and impact characteristics. The mechanical characterisation was carried out for tensile, compression, Flexure, ILSS, Open Hole Tension, Open Hole Compression and Shear (Iosipescu). The impact behaviour were characterised based on a low velocity drop weight impact carried on these laminates. The study shows that the basic properties evaluated were more dictated by the property of the S2-Glass used. The studies show that GLARE™ laminates posses’ high impact damage resistance compared to other composite material. All the test datas generated for this study will be brought out in this document

Motivating Science Students by Acknowledging the Uncertainty of Certainties

In the days of Aristotle, science was considered to be nearly synonomous with philosophy; indeed the philosophers were the only ones who indulged in any form of science besides those who practiced the black art or some form of witchcraft. Then when science is said to have come into its own, science and philosophy drifted farther and farther apart, until they were considered to be entirely incompatible. We are now at the threshold of a new erra, as science and philosophy are drawing closer together again. We hear it said now that one cannot be a creative scientist unless he possesses a cultivated imagination; that these scientists who pursue observations and logic are constantly plagued by "facts" which they refuse to disregard. Materials for this study, were chosen primarily from journals and periodicals in which writers were concerned with the dilemma and inconsistancy in which scientists find themselves at times. Many of these ideas were accumulated from the many remarks of my colleagues and professor with whom this writer has discussed these problems. It seems that very little of this new thought concerning the merging science and philosophy, has drifted into the classrooms of our elementary, junior high, and high schools. It would seem only natural that many of these students would like to know of this recapitulation taking place. Perhaps they could be motivated into some serious considerations of the definitions and the presumptions of science. They could very easily be thrilled to realize that science with all of its accomplishments could be considered to be in a dilemma. They could be mystified to the point of awe, when confronted with the suggestion that common sense is not the same as logic and that the latter is merely a matter of habit, education or communication. There are instances in all branches and at all levels of science when these uncertainties can be mentioned with good possibilities of motivation.Natural Scienc

Charge depletion of n(+)-In0.53Ga0.47As potential wells by background acceptor doping

Published versio

The home environment : influences on the health of young-old and old-old adults in Australia

The physical and societal characteristics of home have been established as important in influencing the health and wellbeing of older adults, yet these have rarely been explored together. There is also limited research into variation across age groups, with older adults often examined as a homogenous group of those 65 years and over. This study advances the knowledge base by using the concept of person–environment (P-E) fit to analyse differences in personal and home environment (physical and societal) characteristics between young-old (65–74 years) and old-old (75 and above) age groups, and to assess how these characteristics influence their self-perceived health. This cross-sectional study draws upon survey data from 1,999 older adult participants from the Australian Housing Conditions Dataset. Descriptive statistics and inferential analysis were used to assess for significant differences between age groups and a binomial logistic regression was utilised to examine influences on health. The analysis found that the factors which influence health varies appreciably between age groups. For the young-old financial strain, being on the fixed-income pension and hypertension were important contributing factors, in contrast for the old-old gender (being male), having depression and the home being modified for disability were key influences. For both age groups heart disease was a contributing factor to perceived health. The results indicate the important contribution to knowledge of incorporating a wide range of person and environment characteristics when exploring P-E fit for older adults. The inclusion of societal aspects, such as financial strain, fixed-income pension, tenure and access to community aged care services when exploring influences on health, arises as a key conclusion of the study. In terms of impact, this research is significant given rising inequalities globally and specifically in the Australian context, the need for policy measures to address income inequality, and its health and social implications for older households.https://www.cambridge.org/core/journals/ageing-and-societyFinancial Managemen

Ultrafast control of donor-bound electron spins with single detuned optical pulses

The ability to control spins in semiconductors is important in a variety of fields including spintronics and quantum information processing. Due to the potentially fast dephasing times of spins in the solid state [1-3], spin control operating on the picosecond or faster timescale may be necessary. Such speeds, which are not possible to attain with standard electron spin resonance (ESR) techniques based on microwave sources, can be attained with broadband optical pulses. One promising ultrafast technique utilizes single broadband pulses detuned from resonance in a three-level Lambda system [4]. This attractive technique is robust against optical pulse imperfections and does not require a fixed optical reference phase. Here we demonstrate the principle of coherent manipulation of spins theoretically and experimentally. Using this technique, donor-bound electron spin rotations with single-pulse areas exceeding pi/4 and two-pulses areas exceeding pi/2 are demonstrated. We believe the maximum pulse areas attained do not reflect a fundamental limit of the technique and larger pulse areas could be achieved in other material systems. This technique has applications from basic solid-state ESR spectroscopy to arbitrary single-qubit rotations [4, 5] and bang-bang control[6] for quantum computation.Comment: 15 pages, 4 figures, submitted 12/2008. Since the submission of this work we have become aware of related work: J. Berezovsky, M. H. Mikkelsen, N. G. Stoltz, L. A. Coldren, and D. D. Awschalom, Science 320: 349-352 (2008

Alterations in Mesenteric Lymph Node T Cell Phenotype and Cytokine Secretion are Associated with Changes in Thymocyte Phenotype after LP-BM5 Retrovirus Infection

In this study, mouse MLN cells and thymocytes from advanced stages of LP-BM5 retrovirus infection were studied. A decrease in the percentage of IL-7+ cells and an increase in the percentage of IL-16+ cells in the MLN indicated that secretion of these cytokines was also altered after LP-BM5 infection. The percentage of MLN T cells expressing IL-7 receptors was significantly reduced, while the percentage of MLN T cells expressing TNFR-p75 and of B cells expressing TNFR-p55 increased. Simultaneous analysis of surface markers and cytokine secretion was done in an attempt to understand whether the deregulation of IFN-Υ secretion could be ascribed to a defined cell phenotype, concluding that all T cell subsets studied increased IFN-Υ secretion after retrovirus infection. Finally, thymocyte phenotype was further analyzed trying to correlate changes in thymocyte phenotype with MLN cell phenotype. The results indicated that the increase in single positive either CD4+CD8- or CD4- CD8+ cells was due to accumulation of both immature (CD3- ) and mature (CD3+) single positive thymocytes. Moreover, single positive mature thymocytes presented a phenotype similar to the phenotype previously seen on MLN T cells. In summary, we can conclude that LP-BM5 uses the immune system to reach the thymus where it interferes with the generation of functionally mature T cells, favoring the development of T cells with an abnormal phenotype. These new T cells are activated to secrete several cytokines that in turn will favor retrovirus replication and inhibit any attempt of the immune system to control infection

Searching for network modules

When analyzing complex networks a key target is to uncover their modular structure, which means searching for a family of modules, namely node subsets spanning each a subnetwork more densely connected than the average. This work proposes a novel type of objective function for graph clustering, in the form of a multilinear polynomial whose coefficients are determined by network topology. It may be thought of as a potential function, to be maximized, taking its values on fuzzy clusterings or families of fuzzy subsets of nodes over which every node distributes a unit membership. When suitably parametrized, this potential is shown to attain its maximum when every node concentrates its all unit membership on some module. The output thus is a partition, while the original discrete optimization problem is turned into a continuous version allowing to conceive alternative search strategies. The instance of the problem being a pseudo-Boolean function assigning real-valued cluster scores to node subsets, modularity maximization is employed to exemplify a so-called quadratic form, in that the scores of singletons and pairs also fully determine the scores of larger clusters, while the resulting multilinear polynomial potential function has degree 2. After considering further quadratic instances, different from modularity and obtained by interpreting network topology in alternative manners, a greedy local-search strategy for the continuous framework is analytically compared with an existing greedy agglomerative procedure for the discrete case. Overlapping is finally discussed in terms of multiple runs, i.e. several local searches with different initializations.Comment: 10 page

Cytomegalovirus Infection of the Cervix Detected By Cytology and Histology: A Report of Five Cases

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72846/1/j.1365-2303.1993.tb00094.x.pd

Single Gene Deletions of Orexin, Leptin, Neuropeptide Y, and Ghrelin Do Not Appreciably Alter Food Anticipatory Activity in Mice

Timing activity to match resource availability is a widely conserved ability in nature. Scheduled feeding of a limited amount of food induces increased activity prior to feeding time in animals as diverse as fish and rodents. Typically, food anticipatory activity (FAA) involves temporally restricting unlimited food access (RF) to several hours in the middle of the light cycle, which is a time of day when rodents are not normally active. We compared this model to calorie restriction (CR), giving the mice 60% of their normal daily calorie intake at the same time each day. Measurement of body temperature and home cage behaviors suggests that the RF and CR models are very similar but CR has the advantage of a clearly defined food intake and more stable mean body temperature. Using the CR model, we then attempted to verify the published result that orexin deletion diminishes food anticipatory activity (FAA) but observed little to no diminution in the response to CR and, surprisingly, that orexin KO mice are refractory to body weight loss on a CR diet. Next we tested the orexigenic neuropeptide Y (NPY) and ghrelin and the anorexigenic hormone, leptin, using mouse mutants. NPY deletion did not alter the behavior or physiological response to CR. Leptin deletion impaired FAA in terms of some activity measures, such as walking and rearing, but did not substantially diminish hanging behavior preceding feeding time, suggesting that leptin knockout mice do anticipate daily meal time but do not manifest the full spectrum of activities that typify FAA. Ghrelin knockout mice do not have impaired FAA on a CR diet. Collectively, these results suggest that the individual hormones and neuropepetides tested do not regulate FAA by acting individually but this does not rule out the possibility of their concerted action in mediating FAA