bluuebunny/crossref_metadata_2025 huggingface dataset:
User Fee Impact on Equitable Access to Care: A Review
Authors: Sharma Anupama
Published: March 2012

Access to care and equity are the two most pertinent issues for policy-makers of the current era. In developing countries, health care is continuously facing budget constraints as central governments’ expenditures do not reach peripheral level of health care. Lack of resources and emphasis on systems’ sustainability has supported the concept of user charges. However, the World Health Organisation (WHO) has recently urged developing countries to not rely on user fee as a source of fund, based on the economic theory that high prices induce negative demand, especially for vulnerable populations, which invariably raises the issue of user fee widening inequity.

This article reviews the evidences from low and middle-income countries to analyze various political agendas supporting user fee policies and their impact on health facilities in terms of utilization and availability of resources in view of barriers to access. The evidences highlighted that access to care is largely affected by unavailability of resources in most African countries whereas India grapples continuously with governance issues for improving efficiency of health care facilities. The success of the concept of user fee lies in careful examination of health care system-capacity issues, providing a support mechanism for the vulnerable and restructuring user fee policy around efficiency rather than cost-recovery mechanism.
Transplant Management from a Vendor’s Perspective
Authors: Mendoza Roger Lee
Published: March 2012

The purpose of this article is to examine organ trafficking and transplant management from a supplier’s or vendor’s perspective, and identify its corresponding health policy implications. A probability sample of living organ vendors from Colombia was surveyed using interviewer-administered questionnaires. The study found that trafficking and relative abundance in the supply of human organs in developing countries, like Colombia, are encouraged by brokered and compensation-based markets involving unrelated organ buyers and sellers, many of whom were foreigners at the time of this study. The state’s regulatory capacity is undermined by patron-client ties, ineffectiveness and corruption in law-enforcement, public tolerance/indifference and the unintended consequences of health policies. A proactive and developmental role for the state requires efficient and creative monitoring and regulatory approaches in light of ever-changing trading rules and operations. Without directly addressing the ambiguity and continuity of underground and legitimate organ transplantation systems, reform efforts will achieve limited success against the backdrop of perfect supply elasticities associated with living donors.
Construction of a nonlinear dynamic characteristic model of pneumatic artificial rubber muscle manipulator using the magnetorheological (MR) brake
Authors: Tomori Hiroki , Midorikawa Yuichiro , Nakamura Taro
Published: March 2012

An artificial rubber muscle as an actuator was paid attention in this study because the manipulator was found to be safe to human when it comes in contact with human. However, this actuator vibrates easily with a late response because of the applied air pressure. Then, the magnetorheological brake that uses the magnetorheological fluid with an early response is built into the joint and controls the vibration. In this article, we have grasped the dynamic characteristics of a manipulator by the construction of a model for improvement in the control performance of the magnetorheological brake. Furthermore, the simulation was performed using the model, and efficient braking of the magnetorheological brake was examined.
Differential Item Functioning for Lesbians, Bisexual, and Heterosexual Women in the Center for Epidemiological Studies Depression Scale
Authors: Birnholz Justin L. , Young Michael A.
Published: March 2012

This study assessed whether the Center for Epidemiological Studies Depression Scale (CES-D) functions equivalently in assessing depressive symptom severity in lesbian, bisexual, and heterosexual women. Using differential item functioning methods, the authors examined (a) whether there is a bias in CES-D total scores and in individual item scores and (b) whether there are differences across female sexuality groups in the construct of depression assessed by the CES-D. Data were collected anonymously online from 273 women. The CES-D total score was unbiased across groups, but there were biases and construct differences in some individual symptoms. Thus, the findings suggest not only that researchers and clinicians can feel secure in using the CES-D in women of different sexual orientations but also that there may be interesting group differences in the manifestation of particular depressive symptoms.
Secondary and Tertiary Support Systems in Schools Implementing School-Wide Positive Behavioral Interventions and Supports
Authors: Debnam Katrina J. , Pas Elise T. , Bradshaw Catherine P.
Published: March 2012

More than 14,000 schools nationwide have been trained in School-Wide Positive Behavioral Interventions and Supports (SWPBIS), which aims both to reduce behavior problems and to promote a positive school climate. However, there remains a need to understand the programs and services provided to children who are not responding adequately to the universal level of support. Data from 45 elementary schools implementing SWPBIS were collected using the School-wide Evaluation Tool and the Individual Student Systems Evaluation Tool (I-SSET) to assess the use of school-wide, Tier 2, and Tier 3 support systems. The I-SSET data indicated that nearly all schools implemented federally mandated Tier 2 and Tier 3 supports (e.g., functional behavioral assessment, student support teams), but few schools implemented other evidence-based programs for students with more intensive needs. School-level demographic characteristics were correlated with the implementation of some aspects of universal SWPBIS, but not with the Tier 2 or 3 supports. Implications of these findings for professional development are discussed.
Bilateral fusion of a supernumerary kidney in a cat
Authors: Silva Juneo Freitas , Boeloni Jankerle Neves , Cima Adriana Monteiro , Serakides Rogéria , Ocarino Natália M
Published: March 2012

A rare case of bilateral fusion of a supernumerary kidney was found during the necropsy of a female, 8-year-old, mixed breed cat that died as a result of azotemia and chronic enteritis. Apart from enteritis, necropsy revealed four kidneys, two in the sublumbar left region and two in the sublumbar right region, with cortical and medullary regions well individualized and independent; however, the pelvis was partially fused, giving rise to a single ureter. The kidneys were small, whitish and firm, with irregular surfaces. Microscopically, all kidneys displayed normal renal glomeruli and tubules among the immature renal glomeruli and tubules with characteristics of hypoplasia. Foci of glomerulosclerosis, nephrocalcinosis and interstitial fibrosis were also observed.
An assessment of the performance of grip enhancing agents used in sports applications
Authors: Carré Matt J , Tomlinson Sarah E , Collins James W , Lewis Roger
Published: March 2012

The performances of four grip enhancing agents, powdered and liquid chalk, rosin and Venice turpentine, were assessed using a bespoke finger friction rig and compared against an agent-free finger. The effectiveness of these agents was measured in dry, damp and wet conditions, to simulate the different environments in which the agents are used. The tests were first done on a polished steel surface and then the powdered and liquid chalk and agent-free finger were tested on sandstone. The tests on the steel showed that in a dry condition, only the Venice turpentine significantly increased the coefficient of friction, compared to no application of agent, with the rosin and powdered chalk actually decreasing the coefficient of friction. It is thought that the reduction in the coefficient of friction is caused by the solid particles acting as a lubricant between the two surfaces. When the fingers were wet, only the granular powder-based agents increased the coefficient of friction. This is because the Venice turpentine cannot adhere well to a wet finger, and therefore is not as effective. When the surface is wet, there is very little difference between the agents due to the water separating the finger surface from the steel. The tests on the sandstone showed no real difference between the lubricants or the different conditions, except for the dry, chalk-free finger, which had a decreased coefficient of friction due to the lubricating properties of the sandstone particles. These results highlight that the use of grip enhancing agents should take into account the moisture in the contact, as in dry conditions, the grip may be optimum when there is no agent used. It also shows that in different sports, different grip enhancing agents should be used.
Study on the influence of critical shear stress on wall slip of spiral oil wedge journal bearing
Authors: Wang Li-Li , Lu Chang-Hou , Ge Pei-Qi , Chen Shu-Jiang
Published: March 2012

With the application of sleeve bearing in high speed, super-high speed and narrow-gap conditions, and the emergence of non-metallic bearing materials, the conventional no-slip boundary condition can be broken down. Critical shear stress is a main parameter in the numerical computation of wall slip. The four modified Reynolds equations for the two-dimensional spiral oil wedge sleeve bearing is established based on the critical shear stress model, in which the circumferential and axial wall slip of the sleeve and axial surface are considered. The shear stress angle is used to compute the circumferential and axial shear stress component and slip velocity. The results show the special structure of spiral oil wedge and the increase of eccentricity ratio make slip more difficult to occur. With the decrease of initial limiting shear stress, pressure, carrying capacity and friction drag decrease. Wall slip has an effect on the oil film rupture position, positive pressure area, and pressure peak. Wall slip occurs first in the large shear stress, the small clearance, and the envelop zone. The slip position and area influence each other in the sleeve and axial surface.
Path-dependent analysis of elastic sphere contact subjected to tangential loading with varying directions
Authors: Huang Shiping , Misra Anil
Published: March 2012

The Cattaneo–Mindlin solutions of contact between elastic spheres and their recent extensions do not consider the sequential application of arbitrarily directed shear forces in the contact tangential plane. For this loading condition, the contact tractions simultaneously undergo loading and unloading. This article presents a path-dependent analysis wherein we use superposition at each loading step to obtain the contact tangential traction, and, subsequently the tangential displacement and compliance. The methodology is illustrated by example calculation of contact shear force–displacement relationship, which shows the formation of hysteretic loop and the noncoaxiality of the shear forces and displacements.
Microstructural characterization of laser-irradiated bulk copper under dry sliding conditions
Authors: Raillard Brice , Gachot Carsten , Hans Michael , Leibenguth Peter , Mücklich Frank
Published: March 2012

The functionalization of surfaces for tribological applications is still a challenging task. There are numerous techniques for improving the friction and wear behaviour of metallic surfaces ranging from different coatings to textured surfaces. A promising approach for textured surfaces is the usage of laser interference patterning by a pulsed nanosecond Nd:YAG laser. Copper samples have been laser patterned using the laser interference metallurgy process. The resulting topographies were evaluated by white light interferometry and scanning electron microscopy in order to study the homogeneity of the structures at both macro- and micro-scales. Electron backscattering diffraction and transmission electron microscopy were performed in order to study the microstructural and oxide layer modifications induced by laser irradiation. Electron backscattering diffraction measurement did not show fine grains but a small proportion of misorientation due to the high quenching rate. Transmission electron microscopy did not allow to observe oxide layers. The friction and wear behaviour of bulk copper samples structured by laser interference metallurgy have been studied under dry sliding conditions using a tribometer in linear reciprocating sliding mode. Friction coefficient measurements revealed that patterned surfaces present a reduction in friction of up to 70% compared to untreated samples due to their good bearing properties and the reduction of the contact area.
Do voters follow the recommendations of voter advice application websites? A study of the effects of kieskompas.nl on its users’ vote choices in the 2010 Dutch legislative elections
Authors: Wall Matthew , Krouwel André , Vitiello Thomas
Published: March 2012

In this article we investigate the electoral effects of a prominent Dutch Voter Advice Application site ( www.kieskompas.nl ). Our research design combines factual data on the recommendations received by users from the site’s log files with users’ responses to pre-advice and post-election survey items. We find that the effects of online recommendations on vote choice depend on the congruence of the recommended party with the users’ pre-existing preferences. When the site recommended a party that was being seriously contemplated by the user, the user was demonstrably more likely to go on to vote for the recommended party. We find that this effect was not visible among voters who indicated that they were only seriously considering one party for their vote choice when they visited the site.
Compliance with requests by children with autism: the impact of sentence type
Authors: Kissine Mikhail , De Brabanter Philippe , Leybaert Jacqueline
Published: March 2012

This study assesses the extent to which children with autism understand requests performed with grammatically non-imperative sentence types. Ten children with autism were videotaped in naturalistic conditions. Four grammatical sentence types were distinguished: imperative, declarative, interrogative and sub-sentential. For each category, the proportion of requests complied with significantly exceeded the proportion of requests not complied with, and no difference across categories was found. These results show that children with autism do not rely exclusively on the linguistic form to interpret an utterance as a request.
Translation and validation of the developmental, dimensional and diagnostic interview (3Di) for diagnosis of autism spectrum disorder in Thai children
Authors: Chuthapisith Jariya , Taycharpipranai Pasinee , Ruangdaraganon Nichara , Warrington Richard , Skuse David
Published: March 2012

This study aimed to examine the effectiveness of a translated version of the short version of the Developmental, Dimensional and Diagnostic Interview (3Di) in discriminating children with autism spectrum disorders (ASDs) from typically developing children. Two groups, comprising 63 children with clinically ascertained ASDs and 67 typically developing children, were interviewed with the short 3Di translated version. Mean 3Di scale scores in each domain of autistic symptoms (social reciprocity, communication, and repetitive/stereotyped behaviors) were significantly higher in the ASD group than in the typically developing group. The optimal receiver operating characteristics curve cut-off scores were found to be 10, 8, and 3 for social reciprocity domain, communication domain, and repetitive/stereotyped behaviors domain, respectively, which are identical to the original English standardization. Corresponding sensitivities and specificities were 76.2% and 80.9% for the social reciprocity domain; 85.7% and 73.5% for the communication domain; and 66.7% and 80.9% for the repetitive behaviors domain. The areas under the curve were 0.89 (95% CI = 0.84–0.94), 0.88 (95% CI = 0.82–0.94), and 0.79 (95% CI = 0.71–0.87), respectively. The short 3Di-Thai version is found to be a useful diagnostic instrument for differentiating between clinically diagnosed children with ASDs and typically developing children, although further replication is needed.
A continuous false belief task reveals egocentric biases in children and adolescents with Autism Spectrum Disorders
Authors: Begeer Sander , Bernstein Daniel M. , van Wijhe Jonas , Scheeren Anke M. , Koot Hans M.
Published: March 2012

This study reports on a new false belief measure in a sample of 124 children and adolescents with or without high functioning autism (HFASD). In the classic paradigm, a participant predicts in which of two discrete locations a deceived protagonist will look for an object. In the current Sandbox task, the object is buried and reburied in a sandbox, thus creating a continuum between locations. Compared to typically developing individuals (n=62), those with HFASD (n=62) showed a larger egocentric bias on the Sandbox task. They failed to take the protagonist’s false belief into account, despite their adequate ability to infer advanced mental states. This indicates that sensitive measures can reveal subtle first order Theory of Mind impairments in HFASD individuals.
Bilateral traumatic renal artery dissection
Authors: Shiber Joseph , Fontane Emily
Published: March 2012

We present a case of bilateral renal artery dissection, with the related computed tomographic images, caused by blunt torso trauma. Discussion includes the etiologies of this type of injury, the diagnostic modalities, and treatment options.
Factors affecting chronic obstructive pulmonary disease early rehospitalization
Authors: Nantsupawat T , Limsuwat C , Nugent K
Published: March 2012

The Centers for Medicare and Medicaid Services has identified early rehospitalization of patients with chronic obstructive pulmonary disease (COPD) exacerbations as a performance measure for hospital care. We retrospectively reviewed patients with COPD who were admitted to University Medical Center, Lubbock, Texas, USA, between October 2010 and March 2011. There were 81 COPD patients with 103 hospitalizations. The mean age was 73.9 years. Pulmonary function tests using the Global initiative for chronic Obstructive Lung Disease criteria had been done in 36 patients (44.4%) and revealed 1 mild (2.8%), 7 moderate (19.4%), 20 severe (55.6%), and 8 very severe (22.2%) cases. Only 38.4% of the patients had prior influenza vaccine. Most patients were treated with antibiotics (81.8%) and corticosteroids (87.9%). The mean length of stay was 4.9 days, and 4 patients died. Most of the patients were discharged home (63.6%) with a median follow-up interval of 14 days. Thirty-two percent did not have long-acting bronchodilators and/or inhaled corticosteroids prescribed on discharge. There were 14 early rehospitalizations within 30 days. Logistic regression analysis indicated that a history of coronary artery disease (odds ratio (OR) 6.4, 95% confidence interval (CI) 1.1–37.4) and unilateral pulmonary infiltrates (OR 12.8, 95% CI 1.9–86.4) significantly increased the early rehospitalization rates. Acute exacerbations of COPD in patients with a history of ischemic heart disease or unilateral pulmonary infiltrates are at increased risk for early readmission. These risk factors should be identified during hospitalization; early follow-up or other interventions may reduce readmissions. Influenza vaccine, maintenance bronchodilators and/or inhaled corticosteroids, and pulmonary function tests were underused, and these standards of care should be provided to improve care.
Testing the Relation Between Fidelity of Implementation and Student Outcomes in Math
Authors: Crawford Lindy , Carpenter Dick M. , Wilson Mary T. , Schmeister Megan , McDonald Marilee
Published: March 2012

The relation between fidelity of implementation and student outcomes in a computer-based middle school mathematics curriculum was measured empirically. Participants included 485 students and 23 teachers from 11 public middle schools across seven states. Implementation fidelity was defined using two constructs: fidelity to structure and fidelity to process. Because of the nested nature of the data, we used a two-level hierarchical linear model for analysis. Four variables, all categorized as fidelity to structure variables, proved significant—total time in intervention ( p <.001), concentration of time in intervention ( p = .03), direct observation of intervention fidelity ( p = .04), and pretest score ( p <.001). Fidelity to process was found to be nonsignificant. The importance of measuring the relation between implementation fidelity and student outcomes is discussed as well as implications for researchers and teachers.
Perceptions of HIV Risk Among Internet-Using, HIV-Negative Barebacking Men
Authors: Klein Hugh , Tilley David L.
Published: March 2012

The current study examines the risk perceptions of HIV-negative men who have sex with men (MSM) who use the Internet to seek unprotected sex. The research questions include the following: How great do these men perceive their HIV risk to be? Are their perceptions based on HIV knowledge or related to their risk behaviors? What factors are associated with greater/lesser perceived risk? Results revealed that more than half of the men believed that they had no or only a slight chance of contracting HIV. Risk perceptions were not related to HIV knowledge or to involvement in HIV risk practices. Four factors were identified as being associated with greater perception of HIV risk: self-identity as a sexual “bottom,” having sex while high, greater use of bareback-focused websites, and younger age. Internet-using HIV-negative men who have sex with men tend to underestimate their risk for acquiring HIV, and interventions need to help them accurately assess their risk.
Barbershops as Venues to Assess and Intervene in HIV/STI Risk Among Young, Heterosexual African American Men
Authors: Baker Jillian Lucas , Brawner Bridgette , Cederbaum Julie A. , White Shawn , Davis Zupenda M. , Brawner William , Jemmott Loretta Sweet
Published: March 2012

African Americans, particularly men, are disproportionately affected by the HIV epidemic. Inconsistent condom use and concurrent sexual partnerships are risk factors; there is limited investigation on how these factors influence HIV risk engagement in young, heterosexual, African American men. To identify contextual risk factors that place young men (18-24 years) at risk for HIV infection, one focus group was conducted with 13 men, and questionnaires were administered to 48 men. Participants were 18 to 24 years old and were recruited from local barbershops. The majority engaged in noncondom use (83%) and had multiple sexual partners (64%). Qualitative themes revealed noncondom use “when in the moment” and enhanced condom use with casual partners. This study provided an understanding of participants’ attitudes, intentions, and behaviors as they related to HIV risk and revealed the need for culturally relevant, theory-based HIV prevention programs to reduce HIV transmission among this population.
Providers’ Attitudes Toward Human Papillomavirus Vaccination in Young Men
Authors: Perkins Rebecca B. , Clark Jack A.
Published: March 2012

Providers’ attitudes toward male human papillomavirus (HPV) vaccination may influence the implementation of new guidelines. Although 24 of 31 (77%) Pediatric and Family Medicine providers interviewed between 2009 and 2010 favored vaccinating males, only 3 (12%) offered vaccination. Providers who did not offer vaccination felt that parents would not be interested in vaccinating sons and were largely unaware of serious HPV-related disease in males.
Male Perpetrators, the Gender Symmetry Debate, and the Rejection–Abuse Cycle
Authors: Brown Jac
Published: March 2012

This review article examined the gender symmetry debate in light of recent research relating to the feminist and family research perspectives on intimate partner violence, providing a context for rethinking perpetrator programs. The concept of coercive control is considered as an explanatory factor in an attempt to integrate the feminist and family research perspectives. The limited effectiveness of perpetrator programs is examined. Research highlighting potential factors that could improve the effectiveness of perpetrator programs is introduced, followed by a discussion of the rejection–abuse cycle, one attempt to incorporate current research into a more inclusive program. The rejection–abuse cycle identifies a pattern of perpetrator behavior, which links rejection, threat to self, defense against threat, and abuse. Finally, suggestions for changing perpetrator programs are elaborated, incorporating past research, which would make them appropriate for both male and female perpetrators. These implications are contextualized within a meta-theory to provide greater clarity for the development of future perpetrator programs.
Imaginings of Space in Immigration Law
Authors: Volpp Leti
Published: March 2012

The law of immigration rests upon the space of the nation-state and on how the movement of bodies in and out of that space is legally imagined. Whether formal legal doctrine recognizes a human body as inside or outside a nation’s territory is deeply consequential. Yet this formal doctrine presumes the nation-state to be a natural and innocent space absent of systems of domination. Case studies of concrete spatial locations demonstrate the social production of space. The case of a Danish reform coupling restrictions on forced marriage with a minimum habitat requirement indicates how space and immigration are produced in relation to gendered notions of race, linking the micro-space of the home with the macro-space of the homeland. The case of African Americans and poor relief in late eighteenth century Massachusetts, whereby immigrant origins were invented to evade town fiscal responsibility, shows how governmental space and immigration are produced as legal fictions. The Commentary concludes with a discussion of cosmopolitanism’s yearning for an ethical place-lessness, and of the challenge posed to nation-state sovereignty and legal imaginings of space by noncitizens whom the state seeks to cast out.
Experimental and numerical analysis of the boundary layer on a vertical plate at low temperature differences
Authors: Držík Milan , Mihálka Peter , Matiašovský Peter
Published: March 2012

The problem of heat convection from surface to air at very low temperature differences has been solved by experimental/numerical approach. The laser-based probing technique of laser beam deviation detection was developed for the measurement of air refractive index gradients. The data obtained were processed by interactive coupling with numerical modelling tools. As it was approved, the key properties of the boundary layer such as temperature and temperature gradient profiles can be analysed in detail and the impact of various factors can be studied. The numerical simulation and the experimental data comparison had shown good coincidence; nevertheless, at a temperature difference of only few degrees, the influence of ambient air movement has to be considered in simulation process. The presented boundary layer analysis can be successfully applied at specific conditions of building physics with the low temperature differences.
Effect of hot rolling on microstructure and transformation cycling behaviour of equiatomic NiTi shape memory alloy
Authors: Ahadi A , Rezaei E , Karimi Taheri A
Published: March 2012

In this study, a near equiatomic NiTi shape memory alloy was hot rolled at 800°C using the thickness reductions of 30 and 50. Optical and transmission electron microscopy, together with X-ray diffraction were used to demonstrate the microstructural changes associated with the hot rolling at different thickness reductions. Repeated transformation cycling was employed to investigate the evolution of R phase during cycling. Microstructural observations revealed the presence of deformation twins embedded in an elongated grain matrix in the hot rolled material. Moreover, it was found that with increasing degree of thickness reduction, the size and number of deformation twins increased throughout the grains. After transformation cycling, higher values of Δ HA→R were noticed in the 50 hot rolled material in comparison to the annealed condition. Transmission electron microscopy microstructure of the 50 hot rolled material transformation cycled up to 50 cycles showed that R phase packets are frequently observed near grain boundaries. The observation of R phase packets near the grain boundaries in the hot rolled material was attributed to the high stress concentrations at these regions.
Preparation and antioxidation properties of glass/yttrium silicates/SiC multilayer coating in both air and combustion atmosphere
Authors: Huang J-F , Wang Y-Q , Zeng X-R , Cao L-Y , Xiong X-B
Published: March 2012

Yttrium silicate coating for SiC precoated C/C composite was prepared by a hydrothermal electrophoretic deposition process. The yttrium silicate coating was sealed with a borosilicate glass outer layer. Phase compositions, surface and cross-section microstructures of the as prepared multilayer coatings were characterised by X-ray diffractometer and scanning electron microscopy. The influences of hydrothermal electrophoretic deposition factors on the phase, microstructure and oxidation resistance of the multilayer coated C/C composites were particularly investigated. Results show that the hydrothermal electrophoretic resulting coating is composed of crystallites with a main phase of Y2Si2O7 and Y2SiO5. The thickness and density of the coatings are improved with the increase in deposition voltage and hydrothermal temperature. Compared with the pack cementation SiC monolayer coating, the as prepared multilayer coatings exhibit better antioxidation property. When oxidation in air and combustion atmosphere, the coated C/C composites lose weight by a linear and a parabolic law respectively. The prepared multilayer coating can effectively protect the C/C composites in combustion atmosphere at 1773 K for 85 h. The flexural strength of the coated specimen arrives at the lowest value at about 1123 K in combustion atmosphere.
Thermally diffused antimony and zinc coatings on magnesium alloys AZ31
Authors: Chen Y , Liu T M , Lu L W , Wang Z C
Published: March 2012

Surface coating often alters or improves the performances of materials. In Mg alloys, surface treatment plays a key role in rendering them appropriate for widespread applications. Here, a thermal diffusion method of antimony and zinc is applied to deal with the surface of Mg alloys AZ31 in order to improve their functionalities. It is found that several compounds are newly generated in the coating layers, which, as a result, enhance the mechanical property and corrosion resistance considerably. By taking into account a variety of treatment temperatures and times, the sample treated by the mixed Sb and Zn powder at 753 K for 6 h is found to exhibit optimal comprehensive properties with a hardness of over 200 HV and the strongest corrosion resistance. This technique may be important for the technological improvement of surfaces of engineering Mg alloys.
Inhibition of manganese oxidising bacterial adhesion on pretreated stainless steel surfaces
Authors: George R P , Muraleedharan P , Tamilvani S , Brijitta J , Tata B V R , Kamachi Mudali U
Published: March 2012

AISI type 304 stainless steel (SS) specimens in solution annealed and cleaned and passivated conditions were exposed to laboratory culture of Leptothrix sp. Epifluorescence studies and total viable count analysis of these specimens showed that bacterial density and biofilm coverage were the least on cleaned and passivated SS surfaces. To confirm whether MnS inclusions play a role in this, adhesion studies at applied potentials, surface characterisation studies using SEM and EDAX analysis and pitting studies with ferric chloride were carried out. These studies clearly revealed the removal of MnS inclusions. This removal leads to a significant reduction in the adhesion of Leptothrix sp. The significance of the present study is that pretreatment of SS by cleaning and passivation inhibited the adhesion of Leptothrix sp. This reduction in adhesion is responsible for the increased corrosion resistance of SS under biofilms in aqueous environments.
High temperature oxidation behaviour of Cr/Co–Al coated superalloy
Authors: Rahman A , Chawla V , Jayaganthan R , Chandra R , Tewari V K , Ambardar R
Published: March 2012

The high temperature oxidation behaviour of nanostructured Cr/Co–Al coatings on Superni-718 substrate, deposited by sputtering, has been investigated. Cyclic high temperature oxidation tests were conducted on bare and coated samples at 900°C for up to 100 cycles. The results showed that a dense scale formed on the coated samples during thermal cycling at the peak temperature of 900°C. The external scale exhibited good spallation resistance during cyclic oxidation testing. The improvement in oxide scale spallation resistance is believed to be the fine grained structure of the coating. The Cr/Co–Al coating on the superalloy substrate showed better performance of cyclic high temperature oxidation resistance due to its possession of β-CoAl phase as Al reservoir and the formation of Al2O3 and spinel phases, such as CoCr2O4 and CoAl2O4, in the scale.
Hot corrosion of nanostructured Cr/Co–Al coatings
Authors: Rahman A , Chawla V , Jayaganthan R , Chandra R , Ambardar R
Published: March 2012

Nanostructured Cr/Co–Al coatings on Superni-718 superalloy substrate are deposited by direct current/radio frequency magnetron sputtering. The microstructure and hot corrosion behaviour of sputtered Cr/Co–Al coatings on Superni-718 superalloy have been investigated in molten salt of 40 wt-%Na2SO4+60 wt-%V2O5 at 900°C. The results showed that a dense scale formed on the coated samples during thermal cycling. The spinel phases of CoCr2O4, CoAl2O4 and NaAlO2 are present in the scale of the corroded coating, resulting in an effective inhibition of O and S diffusion. The sputtered coatings showed better performance of hot corrosion due to its possession of β-CoAl phases (as Al reservoir) in the outer layer of the coating and Cr as an intermediate layer. The relevant corrosion mechanisms are discussed.
Oxidation resistant Si–Mo–Al coating for C/SiC coated carbon/carbon composites at high temperature
Authors: Zhang Y-L , Li H-J , Yao X-Y , Li K-Z , Qiang X-F
Published: March 2012

A Si–Mo–Al coating for protecting carbon/carbon (C/C) composites against oxidation at elevated temperature was prepared on the surface of the C/SiC coated C/C composites by slurry method. The phase composition, microstructure and oxidation resistance of the coating at 1773 K in air were investigated. The results show that the as prepared coating was mainly composed of SiC, MoSi2, Mo(Si,Al)2 and Si. The coating provided excellent oxidation protective ability at 1773 K in air and can effectively protect the C/C composites from oxidation for 150 h. The failure of the coating at 1873 K in air is attributed to the spalling of the glass layer during the oxidation tests.
Effect of nanomechanical and microstructural properties on annealed multilayer Si0·8Ge0·2–Si films
Authors: Lin T-Y , Tsai C-H , Yau W-H , Chou C-P
Published: March 2012

In this study, ultrahigh vacuum chemical vapour deposition was employed to deposit multilayered silicon–germanium (SiGe) films. Subsequently, we take those samples for ex situ thermal treatments in the furnace system (400 and 500°C). The periodic multilayer SiGe with different annealing conditions measured by a commercial nanoindenter observed the slight increase in hardness. The cross-section profile and the microstructure of SiGe multilayer films were characterised by means of atomic force microscopy and transmission electron microscopy. The effect of the thermodynamics of the thin film/substrate system is evidenced by annealing treatment. It is demonstrated that the SiGe multilayer films are more susceptible to plastic deformation while annealing treatments are carried out. The misfit dislocations in the critical pile-up event were observed in the periodical SiGe multilayer that can be relaxed at thermal annealing, thus providing the nanomechanical performance.
Evaluation of corrosion resistance and cytotoxicity of electrodeposited gold on various types of intermediate layers
Authors: dos Santos W A T , Assis S L , Rogero S O , Terada M , Costa I
Published: March 2012

Gold plated surfaces are widely applied in several technical and decorative fields. The two main issues regarding the discussion on the field of precious metal coatings concern the increase in the use of thinner gold layers and ‘Ni free’ substrates. In order to ensure the quality of the final products, the effects of the plated surfaces on their performance require thorough and accurate research. In this paper, the corrosion resistance of gold plated nickel, copper and bronze was investigated by electrochemical methods specifically potentiodynamic polarisation and electrochemical impedance spectroscopy in phosphate buffered saline. The cytotoxicity of the gold plated substrates was also evaluated and compared. The results showed that the substrate related to the best corrosion resistance and cytotoxicity among the tested ones was bronze, and the one with the lowest performance was nickel.
Effect of PEO power modes on structure and corrosion resistance of ceramic coatings on AZ91D Mg alloy
Authors: Yao Z P , Wang D L , Xia Q X , Zhang Y J , Jiang Z H , Wang F P
Published: March 2012

The aim of this work is to investigate the effects of different power modes [constant current (CC), constant voltage (CV) and constant power (CP)] on the structure and corrosion resistance of the plasma electrolytic oxidation ceramic coatings containing Ca and P on AZ91D Mg alloy. The phase composition, morphology and element distribution of the coatings were studied by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The corrosion resistance of the coatings in the simulated body fluid was examined by electrochemical impedance spectroscopy and polarisation curve methods. The results showed that the coatings were of porous structure and mainly composed of MgO. The thickness, surface roughness, the size of the surface micropores and the amount of MgO were all increased with the cell voltage under the same power mode or increased in the sequence CV>CC>CP under the different power modes. The corrosion resistance of coatings was related to the structure characteristics, which were determined by different power modes. Among the different power modes, the corrosion resistance of the coatings is generally increased in the sequence CV>CP>CC, and under the same mode, the proper increase in the cell voltage is liable for improving the corrosion resistance of the coatings.
Ni–Al–Ti coatings obtained by microwave assisted combustion synthesis
Authors: Rosa R , Veronesi P , Poli G , Leonelli C , Corradi A B , Casagrande A , Boromei I
Published: March 2012

Microwaves at 2·45 GHz have been used to ignite the self-propagating high temperature synthesis of Ni and Al powder mixtures (50∶50 at-%) to produce a duplex intermetallic coating on Ti substrates. Owing to the high β-NiAl synthesis reaction enthalpy and the energy provided by the electromagnetic field, the newly formed aluminide is in the liquid phase. Thus, it can react with the underlying Ti substrate, forming a ternary eutectic at the interface, belonging to the Ni–Al–Ti system. The peculiar interlocking microstructure of such ternary layer is responsible for an increase in toughness and hardness compared to the parent NiAl coating. Moreover, the ternary layer's oxidation resistance was tested, showing the possibility of replacing the functionality of hard and brittle NiAl, but limitedly up to 750°C. This can be ascribed to the relatively low Al content in the ternary layer, which hinders the formation of a continuous and protective Al2O3 scale. For this reason, the increase in Al content, or the addition of further elements such as Cr or Si, in the starting powder mixture, helps improve the oxidation resistance of the complex intermetallic coating at the interface, up to the tested temperature of 900°C.
In2O3:H transparent conductive oxide films with high mobility and near infrared transparency for optoelectronic applications
Authors: Koida T , Sai H , Kondo M
Published: March 2012

Hydrogen doped In2O3 (In2O3:H) films show high conductivity, small dispersion of refractive index and very low extinction coefficient in the visible to near infrared wavelengths. The improved properties make this transparent conducting oxide an ideal candidate for a window electrode of optoelectronic devices. This article describes the control of microstructure of In2O3:H, the relationship between the structure and transport properties and the Si based solar cells incorporating the In2O3:H window electrode.
Effect of cyclic indentation on epitaxial GaN films
Authors: Tsai C-H , Yau W-H
Published: March 2012

This paper describes the mechanisms of Berkovich nanoindentation induced mechanical deformation of GaN films under various loading–reloading cycles, analysed using cathodoluminescence, atomic force microscopy (AFM) and SEM. The AFM and SEM studies revealed that bursts, due to the nucleation of dislocations, occurred after nine loading–reloading cycles; these bursts resulted in incipient slip bands and/or the to and fro motion of mobile dislocations under the stress field. Cathodoluminescence analysis indicated the generation of individual dislocations and residual deformation on the GaN film; the decrease in hardness H can be used to determine the material properties of films undergoing repeated loading–reloading cycles.
Residual stress measurement of low temperature plasma surface alloyed layer using X-ray diffraction techniques
Authors: Thaiwatthana S , Jantaping N , Limthongkul P
Published: March 2012

X-ray diffraction (XRD) techniques including stress measurement were applied to untreated, low temperature plasma nitrided and low temperature plasma carburised AISI 304 austenitic stainless steels treated at 425°C for 12 h in H2/N2 and H2/CH4 gases respectively. Relationships between surface microhardness and XRD peak broadening were established. The results also showed that both surface treated layers were under a compressive residual stress. The compressive residual stresses of the low temperature plasma nitrided and the low temperature plasma carburised layers were 2·19 and 1·58 GPa.
Structure and properties of CrxN coating
Authors: Basu A , Dutta Majumdar J , Manna I
Published: March 2012

In the present study, an attempt has been made to produce a coating of mixed nitride (CrN and Cr2N) of ultrafine size on a low alloy high carbon steel by a two-stage hybrid process comprising electrodeposition of Cr (45–85 μm) followed by gas nitriding in controlled atmosphere (using a gas mixture of NH3/Ar = 1∶3) in the temperature range 750–950°C for 2–6 h. The nitrided surface records extremely high hardness (∼19 GPa), enhanced wear resistance and residual compressive stress. Potentiodynamic polarisation test in a 3·56 wt-% NaCl solution shows an improvement in corrosion resistance due to formation of noble nitride. However, presence of brittle nitride phases and related surface roughness seems to deteriorate both tribological and corrosion properties.
Surface structure and electrical properties of Ag based low emissivity film by vacuum magnetron sputtering
Authors: Yang J K , Zhao H L , Li Y X , Dong L Z , Li C , Zhang F C
Published: March 2012

Ag based low emissivity film was deposited on glass by vacuum magnetron sputtering and then post-treated in the glass tempering tempering furnace at 650–700°C for 4, 5 and 6 min respectively. The structural and electrical properties have been investigated as a function of post-treatment time. The results show that with increasing heated time, the structure of the film gradually crystallises and Ag2O (111) appears. The resistivity and sheet resistance have a sharp increase from as deposited to heat treated films and then decrease with increasing time. The calculated emissivity is 0·16 for the as deposited film, increases to 0·39 heated for 4 min and decreases to 0·14 heated for 6 min.
Enhanced magnetic properties in lean rare earth Pr2Fe14B/Fe3B nanocomposite alloys
Authors: Zhang P Y , Pan M X , Ge H L , Yang H F
Published: March 2012

The Pr lean Pr2Fe14B/Fe3B nanocomposite alloys were prepared by melt spinning method and subsequent thermal annealing. The effect of annealing temperature on the magnetic properties and the microstructure of these magnets has been investigated. The results show that the optimal magnetic property of Pr2Fe14B/Fe3B nanocomposite alloy with a high coercivity Hc = 211·4 kA m−1, a large remanence Mr = 1·18 T and a large energy product ( BH)max = 73·9 kJ m−3 has been obtained by controlling the annealing temperature in the amorphous alloy. The enhanced ( BH)max is mainly attributed to the increase in the intergrain exchange coupling effect due to the refined nanocrystal microstructure. This demonstrates that the control of the nanocrystal microstructure in the amorphous alloys plays a significant role for the further improvement of the magnetic properties of these magnets.
Control of particle size and surface properties of fluorinated acrylate microemulsion
Authors: Chen L J , Wu F Q
Published: March 2012

Fluorinated acrylate microemulsion was prepared via co-polymerising methyl methacrylate, butyl acrylate and dodecafluoroheptyl methacrylate that were stabilised by polyethylene glycol mono- p-nonyl phenyl ether and sodium dodecyl benzene sulphonate and initiated by potassium persulphate. Many factors, which had an influence on the particle size and its distribution, had been investigated. It was possible to produce nanoparticles <100 nm and with narrower size distributions using the semicontinuous seeded emulsion polymerisation. Fourier transform infrared spectroscopy confirmed the structure of the microemulsion. The appearance of the microemulsion was translucent and accompanied with blue fluorescence. The stability of the microemulsion was very high. The solid content of the microemulsion was 38·65%. The contact angle of the film was not very high.
On microstructure and fatigue characterisation of cast iron alloyed with PTA deposits
Authors: Shi K Y , Hu S B , Zheng H F
Published: March 2012

In this paper, TiC–W–Cr powders were alloyed on grey cast iron by plasma transferred arc (PTA). The alloying samples were characterised with reference to the microstructure, microhardness, fatigue life and fatigue crack growth. From the results, it is indicated that two distinguishing region, i.e. alloying zone and heat affected zone, were formed on the surface after PTA alloying. The alloying zone mainly consists of primary austenite, martensite, a eutectic of (Fe,Cr)7C3 carbide and austenite as well as the uniformly distributed unmelted TiC particles. Plasma transferred arc alloying TiC–W–Cr eliminated the stress concentration at the edge of graphite and produced hard carbide, resulting in frequent crack deflection. As a result, the Weibull distribution of fatigue life demonstrated that PTA alloying TiC–W–Cr exhibited longer lives compared to matrix and PTA hardening without reinforcement, but more scattered. In addition, on the basis of the careful observation of fatigue crack growth, it was shown that the fatigue crack growth rate could be retarded by PTA alloying TiC–W–Cr at a low stress intensity, but speeded up at high stress intensity due to the brittleness.