Nonuniformity Effect of Surface-Nanocrystalline Materials in Nanoindentation Test

In the present research, microstructures of the surface-nanocrystalline Al alloy material are observed and measured based on the transmission electron microscopy (TEM) technique, and the corresponding mechanical behaviors are investigated experimentally and theoretically. In the experimental research, the nanoindentation test method is used, and the load and microhardness curves are measured, which strongly depend on the grain size and grain size nonuniformity. Two kinds of the nanoindentation test methods are adopted: the randomly selected loading point method and the continuous stiffness method. In the theoretical modeling, based on the microstructure characteristics of the surface-nanocrystalline Al alloy material, a dislocation pile-up model considering the grain size effect and based on the Mott theory is presented and used. The hardness-indent depth curves are predicted and modeled.

Can the change in the composition of the US GDP explain the Great Moderation? A test via oil price shocks

The paper investigates whether the growing GDP share of the services sector can contribute to explain the great moderation in the US. We identify and analyze three oil price shocks and use a SVAR analysis to measure their economic impact on the US economy at both the aggregate and the sectoral level. We find mixed support for the explanation of the great moderation in terms of shrinking oil shock volatilities and observe that increases (decreases) in oil shock volatilities are contrasted by a weakening (strengthening) in their transmission mechanism. Across sectors, services are the least affected by any oil shock. As the contribution of services to the GDP volatility increases over time, we conclude that a composition effect contributed to moderate the conditional volatility to oil shocks of the US GDP.

Desenvolvimento e validação de sistema multiplex X-STR para identificação humana por DNA

Novas metodologias de análise molecular voltadas para estudos populacionais, clínicos, evolutivos, da biodiversidade e identificação forense foram desenvolvidas com base em marcadores microssátelites ou STR Short Tandem Repeats. Os marcadores STR, que estão amplamente espalhados nos genomas e se caracterizam por apresentar alto grau de polimorfismo, podem ser analisados a partir da amplificação por PCR (Reação em Cadeia da polimerase). A análise foi facilitada a partir do desenvolvimento de sistemas de amplificação simultânea de múltiplos STR (multiplex STR) e com a detecção automatizada dos produtos de amplificação marcados por fluorescência. Recentemente, o uso de marcadores STR do cromossomo X (X-STR) tornou-se significativo na prática forense. Devido ao seu modo de transmissão, os X-STR são úteis em situações particulares de investigação de relações de parentesco, apresentando vantagens sobre o uso de STR autossômicos. Este estudo teve como principal objetivo o desenvolvimento e validação de sistema multiplex, denominado LDD (X-STR) Decaplex, capaz de amplificar dez loci X-STR (DXS7133, DXS7424, DXS8378, DXS6807, DXS7132, DXS10074, DXS7423, DXS8377, GATA172D05 e DXS10101) para aplicação em genética populacional, identificação e análises forenses. Utilizando o LDD (X-STR) Decaplex 170 indivíduos autodenominados afrodescendentes, não aparentados geneticamente, foram genotipados. As freqüências alélicas e genotípicas não apresentaram desvio do equilíbrio de Hardy-Weinberg e estão em concordância com aquelas observadas em outros estudos. Os haplótipos observados foram únicos em indivíduos de amostra masculina. A análise de desequilíbrio de ligação não revelou associação entre os marcadores X-STR. A diversidade genética foi elevada, variando entre 0,6218 para o locus DXS7133 a 0,9327 para o locus DXS8377. Os parâmetros de Probabilidade de Vinculação (PV), Índice de Vinculação (IV), Poder de Exclusão (PE), Poder de Discriminação e Razão de Verossimilhança foram também elevados, demonstraram que os dez X-STRs são altamente polimórficos e discriminativos na população estudada. A concentração mínima de DNA para a amplificação dos loci do LDD (X-STR) Decaplex é de 0,5 ng e verificamos que amplificação por PCR pode ser afetada quando são adicionados mais de 5 ng de DNA nas reações. Os percentuais de bandas stutter foram elevados para os loci DXS7132 e DXS8377. No teste de reprodutibilidade observamos consistência entre as tipagem de diferentes amostras biológicas, incluindo as de restos mortais. No teste de mistura a proporção limite em que observamos a coexistência de duas espécies biológicas foi de 2,5:1ng (feminino-masculino). Os resultados evidenciaram que os loci do LDD (X-STR) Decaplex são altamente informativos, consistindo, em conjunto, uma ferramenta importante em estudos de identificação humana e de relações de parentesco.

Preparation and characterization of a novel pyrrole-benzophenone copolymerized silica nanocomposite as a reagent in a visual immunologic-agglutination test.

Biological sensing is explored through novel stable colloidal dispersions of pyrrole-benzophenone and pyrrole copolymerized silica (PPy-SiO(2)-PPyBPh) nanocomposites, which allow covalent linking of biological molecules through light mediation. The mechanism of nanocomposite attachment to a model protein is studied by gold labeled cholera toxin B (CTB) to enhance the contrast in electron microscopy imaging. The biological test itself is carried out without gold labeling, i.e., using CTB only. The protein is shown to be covalently bound through the benzophenone groups. When the reactive PPy-SiO(2)-PPyBPh-CTB nanocomposite is exposed to specific recognition anti-CTB immunoglobulins, a qualitative visual agglutination assay occurs spontaneously, producing as a positive test, PPy-SiO(2)-PPyBPh-CTB-anti-CTB, in less than 1 h, while the control solution of the PPy-SiO(2)-PPyBPh-CTB alone remained well-dispersed during the same period. These dispersions were characterized by cryogenic transmission microscopy (cryo-TEM), scanning electron microscopy (SEM), FTIR and X-ray photoelectron spectroscopy (XPS).

An improved TM method for full two-port calibration of the asymmetric test fixtures

Three known standards, including at least one transmission standard, are normally required for the full two-port calibration of test fixtures. Based on the triple-through method, a new general-purpose calibration procedure using only one known reflection standard is proposed in this paper. The experimental results show that our method call provide a simple and accurate approach to fall two-port calibration of the asymmetric test fixtures. (c) 2005 Wiley Periodicals, Inc.

Phase uncertainty in calibrating microwave test fixtures

The problem of phase uncertainty arising in calibration of the test fixtures is investigated in this paper, It is shown that the problem exists no matter what kinds of calibration standards are used. It is also found that there is no need to determine the individual S-parameters of the test fixtures. In order to eliminate the problem of phase uncertainty, three different precise (known) reflection standards or one known reflection standard plus one known transmission standard should be used to calibrate symmetrical test fixtures. For the asymmetrical cases, three known standards, including at least one transmission standard, should be used. The thru-open-match (TOM) and thru-short-match (TSM) techniques are the simplest methods, and they have no bandwidth limitation. When the standards are imprecise (unknown), it is recommended to use any suitable technique, such as the thru-reflect-line, line-reflect-line, thru-short-delay, thru-open-delay,line-reflect-match, line-reflect-reflect-match, or multiline methods, to accurately determine the values of the required calibration terms and, in addition, to use the TOM or TSM method with the same imprecise standards to resolve the phase uncertainty.

Single ridge waveguide electroabsorption modulated DFB laser for 2.5Gb/s transmission

In this paper we proposed a single ridge waveguide electroabsorption modulated distributed feedback laser (EML) for long-haul high-speed optical fiber communication system. This EML was successfully fabricated by two step metal organic vapor phase epitaxy (MOVPE) including selective area growth (SAG) and helium partially implantation. No obvious changes of the threshold current (< 0.2 mA), extinction ratio (< 0.1 dB), output power (< 0.2 dBm) and isolation resistance were achieved in the preliminary aging test. With 2.5 Gb/s NRZ modulation, no power penalty was observed after the optical signal was transmitted through 280 Km normal single mode fiber.

Construction and test of Wien-filter combined with RIBLL

A recoil separator Wien-filter which was developed for the Radioactive Ion Beam Line in Lanzhou (RIBLL) as an extension is described. It consists of 2 quadruple triplets and a standard Wien-filter. It was designed for study of the fusion-evaporation reactions. The overall design, background suppression, the transmission efficiency, the angular acceptance and the momentum acceptance have been described. All the performances fulfil the designed requirements. Based on the test results, with some modifications the investigations of the nuclei with Z <= 110 and the drip-line nuclei in the medium-heavy mass region can be carried out with this facility.

Electrode catalysts behavior during direct ethanol fuel cell life-time test

In the present paper, a 60 h life-time test of a direct ethanol fuel cell (DEFC) at a current density of 20 mA cm(-2) (the beginning 38 h) and 40 mA cm(-2) (the last 22 h) was carried out. After the life-time test, the MEA could not achieve the former performance. X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX) were employed to characterize the anode and cathode catalyst before and after the life-time test. The XRD and TEM results showed that the particle size of the anode catalyst increased from 2.3 to 3.3 nm and the cathode from 3.0 to 4.6 nm. The EDX results of PtSn/C anode catalysts before and after the life-time test indicated that the content of the oxygen and tin, especially the content of the platinum, decreased prominently after the life-time test. The results suggest that the agglomeration of electrocatalysts, the destruction of the anode catalyst together with the fuel/water crossover from anode to cathode concurrently contribute to the performance degradation of the DEFC. (C) 2005 Elsevier B.V. All rights reserved.

Coherent wavelength division multiplexing: a novel transmission format for high spectral density optical communication networks

In this thesis a novel transmission format, named Coherent Wavelength Division Multiplexing (CoWDM) for use in high information spectral density optical communication networks is proposed and studied. In chapter I a historical view of fibre optic communication systems as well as an overview of state of the art technology is presented to provide an introduction to the subject area. We see that, in general the aim of modern optical communication system designers is to provide high bandwidth services while reducing the overall cost per transmitted bit of information. In the remainder of the thesis a range of investigations, both of a theoretical and experimental nature are carried out using the CoWDM transmission format. These investigations are designed to consider features of CoWDM such as its dispersion tolerance, compatibility with forward error correction and suitability for use in currently installed long haul networks amongst others. A high bit rate optical test bed constructed at the Tyndall National Institute facilitated most of the experimental work outlined in this thesis and a collaboration with France Telecom enabled long haul transmission experiments using the CoWDM format to be carried out. An amount of research was also carried out on ancillary topics such as optical comb generation, forward error correction and phase stabilisation techniques. The aim of these investigations is to verify the suitability of CoWDM as a cost effective solution for use in both current and future high bit rate optical communication networks

FREQUENCY SELECTIVE SURFACE WITH DUAL BAND SWITCHABLE REFLECTION AND TRANSMISSION CHARACTERISTICS

A pin diode-loaded active doubly periodic flat strip FSS is shown to act as a dynamic screen. It is shown that by means of d.c. bias control, we can utilize the screen in, (1) transmission mode as a dual band electromagnetic shutter, or with the inclusion of a ground plane in reflection mode, (is (2) it dual band refection canceller. (3) an amplitude shift keying (ASK) spatial modulator. The properties of the FSS are characterized using a specially designed parallel plate waveguide simulator that permits normal incidence excitation of the FSS under test. (C) 2009 Wiley Periodicals. Inc. Microwave Opt Technol Lett 51: 2059-2061, 2009; Published online in Wiley Inter-Science (www. interscience.wiley.com). DOI 10.1002/mop.24547

Risk factors for the introduction and within-herd transmission of Mycobacterium avium subspecies paratuberculosis (MAP) infection in 59 Irish dairy herds

Since 1994, Irish cattle have been exposed to greater risks of acquiring Mycobacterium avium subspecies paratuberculosis (MAP) infection as a consequence of the importation of over 70,000 animals from continental Europe. In recent years, there has been an increase in the number of reported clinical cases of paratuberculosis in Ireland. This study examines the prevalence of factors that promote the introduction and within-herd transmission of Mycobacterium avium subspecies paratuberculosis (MAP) on selected Irish dairy farms in the Cork region, and the association between these factors and the results of MAP screening tests on milk sock filter residue (MFR). A total of 59 dairy farms, selected using non-random methods but apparently free of endemic paratuberculosis, were enrolled into the study. A questionnaire was used to collect data about risk factors for MAP introduction and transmission. The MFR was assessed on six occasions over 24 months for the presence of MAP, using culture and immunomagnetic separation prior to polymerase chain reaction (IMS-PCR). Furthermore, blood samples from all entire male and female animals over one year of age in 20 herds were tested by ELISA. Eighteen (31%) farms had operated as closed herds since 1994, 28 (47%) had purchased from multiple sources and 14 (24%) had either direct or indirect (progeny) contact with imported animals. Milk and colostrum were mixed on 51% of farms, while 88% of farms fed pooled milk. Thirty (51%) herds tested negative to MFR culture and IMS-PCR, 12 (20%) were MFR culture positive, 26 (44%) were IMS-PCR positive and seven (12%) were both culture and IMS-PCR positive. The probability of a positive MFR culture was significantly associated with reduced attendance at calving, and with increased use of individual calf pens and increased (but not significantly) if multiple suckling was practised. There was poor agreement between MFR culture and MFR IMS-PCR results, but moderate agreement between MFR culture and ELISA test results. This study highlights a lack of awareness among Irish dairy farmers about the effect of inadequate biosecurity on MAP introduction. Furthermore, within-herd transmission will be facilitated by traditional calf rearing and waste management practices. The findings of viable MAP in the presence of known transmission factors in non-clinically affected herds could be a prelude to long-term problems for the Irish cattle and agri-business generally.

Infection-control strategies for preventing the transmission of meticillin-resistant Staphylococcus aureus (MRSA) in nursing homes for older people (Review)

Background: Nursing homes for older people provide an environment likely to promote the acquisition and spread of meticillin-resistant Staphylococcus aureus (MRSA), putting residents at increased risk of colonisation and infection. It is recognised that infection control strategies are important in preventing and controlling MRSA transmission.

Objectives: The objective of this review was to determine the effects of infection control strategies for preventing the transmission of MRSA in nursing homes for older people.

Search strategy: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2009, Issue 2), the Cochrane Wounds Group Specialised Register (searched May 29th, 2009). We also searched MEDLINE (from 1950 to May Week 4 2009), Ovid EMBASE (1980 to 2009 Week 21), EBSCO CINAHL (1982 to May Week 4 2009), British Nursing Index (1985 to May 2009), DARE (1992 to May 2009), Web of Science (1981 to May 2009), and the Health Technology Assessment (HTA) website (1988 to May 2009). Research in progress was sought through Current Clinical Trials (www.controlled-trials.com), Medical Research Council Research portfolio, and HSRPRoj (current USA projects). SIGLE was also searched in order to identify atypical material which was not accessible through more conventional sources.

Selection criteria: All randomised and controlled clinical trials, controlled before and after studies and interrupted time series studies of infection control interventions in nursing homes for older people were eligible for inclusion.

Data collection and analysis: Two authors independently reviewed the results of the searches.

Main results: Since no studies met the selection criteria, neither a meta-analysis nor a narrative description of studies was possible.

Authors' conclusions: The lack of studies in this field is surprising. Nursing homes for older people provide an environment likely to promote the acquisition and spread of infection, with observational studies repeatedly reporting that being a resident of a nursing home increases the risk of MRSA colonisation. Much of the evidence for recently-issued United Kingdom guidelines for the control and prevention of MRSA in health care facilities was generated in the acute care setting. It may not be possible to transfer such strategies directly to the nursing home environment, which serves as both a healthcare setting and a resident's home. Rigorous studies should be conducted in nursing homes, to test interventions that have been specifically designed for this unique environment.

Network Usage Determination for Transmission Cost Allocation using a Transformer Analogy

This study presents a new method for determining the transmission network usage by loads and generators, which can then be used for transmission cost/loss allocation in an explainable and justifiable manner. The proposed method is based on solid physical grounds and circuit theory. It relies on dividing the currents through the network into two components; the first one is attributed to power flows from generators to loads, whereas the second one is because of the generators only. Unlike almost all the available methods, the proposed method is assumption free and hence it is more accurate than similar methods even those having some physical basis. The proposed method is validated through a transformer analogy, and theoretical derivations. The method is verified through application to the IEEE 30 bus system and the IEEE 118 test system. The results obtained verified many desirable features of the proposed method. Being more accurate in determining the network usage, in an explainable transparent manner, and in giving accurate cost signals, indicating the best locations to add loads and generation, are among the many desirable features.

A new method for transmission loss allocation considering the circulating currents between generators

A new method is presented for transmission loss allocation based on the separation of transmission loss caused by load and the loss due to circulating currents between generators. The theoretical basis for and derivation of the loss formulae are presented using simple systems. The concept is then extended to a general power system using the Ybus model. Details of the application of the proposed method to a typical power system are presented along with results from the IEEE 30 bus test system. The results from both the small system and the standard IEEE test system demonstrate the validity of the proposed method.