bluuebunny/crossref_metadata_2025 huggingface dataset:
Selection of Adaptive Power Control Parameters for a Cold Milling Machine and its Simulation
Authors: Ma Peng-yu , Hu Yong-biao , Zhang Xin-rong
Published: April 2008

The influence on the power consumption of the cold milling machine and the load feature of the engine are firstly analyzed. The selection of the most effective control parameter to make good use of the engine power is studied theoretically. Based on these analyses, a simulation model of the cold milling machine is designed with the software AMEsim4.2. Whether the engine power utilization of the cold milling machine is reasonable or not is verified through simulations in which the adaptive power control system is used. The results show that using the work speed of the cold milling machine as the control parameter is reasonable and effective; the engine of the milling machine can be set to work at its rated power by the self-adjustment of the adaptive power control system. In this case, the rated power utilization ratio of the engine is improved more than 10.2% and the machine productivity is raised at least 6.32% in various working conditions. The theoretical basis and novel practical methodology can be employed in utilizing the engine power and increasing the machine productivity.
Professional Development Issues for School Psychologists
Authors: Wnek Andrew C. , Klein Gabrielle , Bracken Bruce A.
Published: April 2008

This study queried practicing school psychologists in the United States about the extent to which advances in the field have improved their individual service provision and fostered a desire for additional professional development. The researchers surveyed 1,000 members of the largest professional organization for school psychologists in the United States (NASP) and examined 336 survey respondents' perceptions as a total sample and by demographic subgroups. The results highlight the uniformity of US psychologists' perceptions, nationwide, regardless of respondents' demographic characteristics. The researchers conclude that school psychologists should more actively advocate for and influence the direction of future training initiatives and local, state, national and international organizations should provide professional development in alignment with the needs of practicing psychologists.
Strategies for Implementing Performance Measurement in Behavioural Health Care Organisations
Authors: Colton David
Published: April 2008

Performance measurement provides a basis for demonstrating accountability and a foundation for performance improvement. Nonetheless, practitioners tend to be cautious of attempts to assess the efficiency and effectiveness of behavioural services, particularly given the qualitative nature of some treatment interventions (such as process-oriented therapies) and the limita-tions associated with many mental health instruments. This article examines the rationale for resisting performance measurement and then describes actions that behavioural health care organisations can take to create a systematic approach to collecting and using these measures to improve organisational effectiveness and client services. Examples from the author's work setting, a publicly funded psychiatric hospital for children and adolescents, are provided to demonstrate how these actions have been operationalised.
Livelihood, Poverty and Morbidity
Authors: Meher Rajkishor
Published: April 2008

The tribals of the Orissa not only deserve a sustainable form of livelihood, but also proper access to adequate health care facilities, as poverty and morbidity go together to cause vicious circle. Because of a higher incidence of poverty, tribals fail to acquire adequate calories, nutrition and vitamins to keep them immune from various diseases. On the other hand, poverty further diminishes their earning capability due to the affliction of various seasonal and endemic diseases round the year. Hence, for the capacity building of poor tribals to enable them to come out of the poverty trap, apart from livelihood-sustaining measures in an era of economic liberalisation and globalisation, strengthening of public health care facilities in tribal areas needs foremost attention. More so as tribals are usually found to be residing in environmentally adverse and physically less accessible areas, with scattered human settlements, and are more vulnerable to various types of endemic, contagious and seasonal diseases due to mass poverty, ignorance and absence of proper health care in-frastructure and services. Based on the field data collected on different occasions in different tribal districts of Orissa for various research studies and also from published secondary data, this article makes an attempt to analyse the livelihood patterns and living conditions of the tribals of Orissa, and the concomitant morbidity and status of health care services in the tribal regions of the state. The article also critically examines the existing health care policy of the state and its efficacy and relevance for the downtrodden in the present context of economic reforms, and the withdrawal of the state from subsidised health care services.
Unmet Needs for Medical Care for Sick Children in Rural Bangladesh
Authors: Alam Nurul
Published: April 2008

While a country's health policy aims to provide health services to all who need them, very little in known about unmet need for medical care from users’ perspectives in Bangladesh. This study examines unmet medical need of 2,123 under-15 sick children by illness and child's socio-economic characteristics in rural Bangladesh. The 1996 health and socio-economic survey conducted in Matlab (Peterson et al. 1996) recorded children's chronic and acute morbidity and unmet needs for medical services in mothers’ views to combat illness. The survey also recorded household socio-economic data. Logistic regression was used to examine the effects of illness and household socio-economic characteristics on unmet medical need for sick children.

The results reveal that unmet need for medical care was 5.4 per cent for children with acute illnesses, and 30.2 per cent for children with chronic illnesses. It was lower for girls than for boys. Economic inequalities existed: odds ratio of unmet medical need for children in top one-third of households was 0.42 (95 per cent CI = 0.28–0.64) times the unmet medical need for children in lowest one-third. The critically high unmet needs for children's chronic morbidity reveal that the chronic disease control programme needs urgent revisiting and strengthening.
Strategies for implementing Health-Promoting Schools in a province in China
Authors: Aldinger Carmen , Zhang Xin-Wei , Liu Li-Qun , Guo Jun-Xiang , Yu Sen Hai  , Jones Jack
Published: April 2008

After successful pilot projects in 10 schools (four schools with tobacco control and six schools with nutrition interventions, plus 10 control schools), Health and Education officials in Zhejiang Province, China, decided to scale up Health-Promoting Schools (HPS) systematically over the entire province, starting with an initial cohort of 51 additional schools, reaching from primary to vocational schools. Interviews with school personnel during the first phase of scaling up illuminated the key pre-implementation, implementation, and monitoring and evaluation activities. Pre-implementation activities included choosing an entry point, setting up a special HPS committee, and establishing a work plan. Implementation activities included conducting mobilization meetings, prioritizing health, popularizing the HPS concept, ensuring community cooperation and participation, acting as role models, offering training, and using new teaching and learning methods. Monitoring and evaluation activities included process, baseline, and final evaluations and changing standards of evaluation to a more holistic evaluation that schools go through to become Health-Promoting Schools. Schools also reported that they faced — and overcame — a number of challenges including understanding and integrating the HPS concept and lack of professional development and support. Results revealed that schools transitioned from a passive model of education to interactive pedagogy put priority on health and viewed it as a co-responsibility, reshaped assessment to a more holistic approach and called for more training and technical support. Participants mentioned that they gained knowledge and skills and developed a deeper understanding about health. Health impact was also demonstrated, for instance in reduced injuries and reduced smoking, and educational impact was demonstrated, for instance in improved relationships of children to parents and teachers, improved social qualities, and improved teacher satisfaction. (Promot Educ, 2008; 15 (1): pp. 24-29)
“Un risque, ça va ! Trois risques, bonjour les dégâts?” Les difficultés de l'éducation pour la santé à prévenir des risques comportementaux multiples
Authors: Peretti-Watel Patrick , Obadia Yolande , Arwidson Pierre , Moatti Jean-Paul
Published: April 2008

L'éducation pour la santé peut avoir des effets inattendus, voire des effets pervers, notamment lorsqu'elle s'attaque d'une part à des risques de pathologies multiples et d'autre part à un même facteur de risque qui peut être relié à plusieurs pathologies différentes. Certains effets inattendus peuvent être consécutifs à une information préventive trop abondante, ou trop ciblée. Dans le premier cas, l'information peut susciter un relativisme face à tel ou tel risque sanitaire, ou être utilisée par certains intérêts pour s'opposer à des objectifs de santé publique. Lorsque l'information est trop ciblée, elle peut alimenter des réactions discriminatoires à l'égard de groupes à risque, ce qui peut se traduire par un déni du risque chez ceux qui ne se considèrent pas concernés par cet étiquetage. Ensuite, des actions préventives ont parfois un effet inattendu, ou pas d'effet du tout, parce que la conduite visée est fonctionnelle pour l'individu. Lorsqu'on veut prévenir une conduite à risque, il faut donc prendre en compte les menaces qu'elle sert à éviter (les risques concurrents), ainsi que les autres conduites risquées qui permettent d'atteindre les mêmes objectifs (les risques substituables). Pour comprendre et éviter ces divers écueils, il faut admettre que le public a des connaissances et des croyances, souvent enracinées dans l'expérience quotidienne et donc difficiles à remettre en cause. Il faut aussi replacer la conduite à risque visée dans son contexte, en identifiant sa fonction, les risques concurrents et les risques substituables, ce qui requiert d'approfondir le dialogue avec les sciences sociales. A l'avenir, la nécessité d'une approche globale des problèmes de santé se fera de plus en plus sentir, puisque la prévention des risques comportementaux porte de plus en plus sur des facteurs de risque multiples d'une même pathologie ainsi que sur la prévention concomitante de pathologies multiples. (Promot Educ 2008;15(1): 40-45).
Early Detection of an Acute Cerebral Event During Cardiopulmonary Bypass Using a Bispectral Index Monitor
Authors: Leggat Christopher S. , Fischer Gregory W.
Published: April 2008

A case in which the bispectral index monitor underwent an acute change that was most likely the earliest indicator of an intraoperative stroke during replacement of an aortic valve is discussed in this study. The timely response to this intraoperative event may have facilitated a better outcome by virtue of more rapid interventions to limit the severity of the injury.
South Asian Parents' Constructions of Praising Their Children
Authors: Paiva Nupur Dhingra
Published: April 2008

While praise is considered an important element in moulding children's behaviour and is central to parent-training advice in the UK today, the literature from nonwestern cultures suggests that some communities do not view praise as positive. There is currently a dearth of systematic knowledge about how minority ethnic parents in Britain view praise. This qualitative study used thematic analysis to explore the childrearing beliefs of immigrant parents from South Asian backgrounds living in inner-city London, with a focus on their constructions of praising their preschool children. The emerging themes suggest that participants see young children's behaviour as instinctual and view instruction as the main parenting strategy required. Demonstrations of physical warmth and tangible rewards were widely used. While verbal praise was used to encourage compliance, these parents advised caution, saying that praising children risked the development of psychological attributes that were culturally judged as dysfunctional. There was relatively little emphasis on the individual child's ability but more on its effect on others in the hierarchy. These themes have some fundamental implications for the practice of clinical psychology in multicultural communities.
Taking a Systemic Perspective on Cognitive Assessments and Reports: Reflections of a Paediatric and Adolescent Psychology Service
Authors: Griffin Angela , Christie Deborah
Published: April 2008

This article discusses current approaches in the neuropsychological assessment of children and young people. An audit of assessments found that nearly a quarter of referrals for neuropsychological assessments could have been resolved more effectively without completing a cognitive assessment. The audit also found that families and young people often found the report difficult to understand or unhelpful. We highlight the difficulties we have had with specific aspects of this process in a paediatric and adolescent medicine psychology service, and discuss the approaches we have taken in the light of feedback from children, young people and parents. The article describes how a systemic framework has been used in processing and responding to referrals. It also gives case examples illustrating how systemic theory and principles have been incorporated into the written reports. Families have responded very favourably to the use of creative and child friendly language in the feedback.
Early and Middle Adolescents' Autonomy Development: Impact of Maternal HIV/AIDS
Authors: Murphy Debra A. , Greenwell Lisa , Resell Judith , Brecht Mary-Lynn , Schuster Mark A.
Published: April 2008

Progression toward autonomy is considered of central importance during the adolescent period. For young adolescents with an HIV-infected parent, there may be additional challenges. This study investigated current autonomy among early and middle adolescents affected by maternal HIV ( N = 108), as well as examined longitudinally the children's responsibility taking when they were younger (age 6—11; N = 81) in response to their mother's illness and their current autonomy as early/middle adolescents. In analyses of self-care and family autonomy, children with greater attachment to their mothers had higher autonomy, and there was a trend for children who drink or use drugs alone to have lower autonomy. In analyses of management autonomy, attachment to peers was associated with higher autonomy. Trajectory group findings indicate that those children who had taken on more responsibility for instrumental caretaking roles directly because of their mother's illness showed better autonomy development as early and middle age adolescents. Therefore, `parentification' of young children with a mother with HIV may not negatively affect later autonomy development.
Young People at Risk of Offending: Their Views on a Specialist Mental Health Service in South East London
Authors: Naylor Chris , Lincoln John , Goddard Nick
Published: April 2008

This article explores the views of young people regarding their involvement with a specialist mental health service for adolescents who offend or are at risk of offending. The main aims are to shed light on means of engaging this group in therapeutic work, and to illustrate the use of qualitative techniques in the evaluation of health services. Twenty clients and ex-clients were interviewed using a semistructured schedule. Responses were analysed using a thematic indexing technique. Findings show that the majority felt the service had helped them to some extent, despite initial resistance to referral. Five factors which helped practitioners overcome this resistance were identified: (1) A manner which demonstrates respect and commitment; (2) being able to operate flexibly and offer outreach appointments; (3) clinical effectiveness; (4) making therapeutic sessions seem personally relevant; and (5) explaining clearly the role of the service. Attention should be paid to these areas if mental health services are to support this challenging client group.
Thinking beyond moral panic
Authors: Hier Sean P.
Published: April 2008

This article conceptualizes processes of moralization as rational, dialectic constructions of self and other that are transmitted through everyday discourses of risk management and harm avoidance. One explanation is provided for how volatile moralizing discourses, as a temporary extension of moralization in everyday life, are transmitted through configurations of grievance and risk under neo-liberalism. The article offers insights into the diverse ways in which moralization operates, and it critically assesses moral panic theory's continued use in criminological research.
Decoding 'encoding'
Authors: Doran Nob
Published: April 2008

A generation ago, Hall et al.'s (1978) work Policing the Crisis gave a sophisticated analysis of the British media's mundane ability to 'encode' events so as to help produce a moral panic about mugging. Although this work remains relatively neglected in its home country, it has begun to be utilized for empirical analysis in North America. This article suggests, however, that Hall et al.'s analysis remains a poor import. This is not, however because of its age or cultural specificity. Instead Policing the Crisis fails, quite simply because it repeats in its own analysis the same 'ideological practices' (albeit at a higher logical level), which it discovered in its empirical investigation of the British media.
Angiography and embolisation in blunt splenic injury: a review
Authors: Klapheke WP , Harbrecht BG
Published: April 2008

The surgical care of patients has evolved over the last 50 years. Operative intervention in the face of blunt spleen injury has been supplanted by non-operative techniques. Two of the newest techniques, angiography and embolisation, are reviewed in this article with references to patient selection, technique used and outcomes. Furthermore, current weaknesses in the data available are discussed in order to provide surgeons with a complete overview of the techniques.
Scapula fractures: A review
Authors: Theivendran Kanthan , McBryde Callum W , Massoud Samir N
Published: April 2008

Fractures of the scapula are uncommon and are generally the result of high energy trauma with associated serious injuries. A majority can be managed conservatively but significant displacement of fracture fragments especially involving the glenoid articular surface may require operative fixation to prevent serious functional disability. This review discusses the diagnosis, classification and treatment of these injuries.
Popular news in the 21st century Time for a new critical approach?
Authors: Harrington Stephen
Published: April 2008

This article is a brief review and critique of the main scholarly approaches to thinking about popular forms of news in the late 20th and early 21st centuries, particularly in regards to broadcast television. Rather than advocating the merits of either popular or `hard' news, it discusses the possibility of finding (or revisiting) a critical approach to popular news and current affairs1 journalism that charts a suitable middle ground: one that can accommodate the emergence of popular informational programs (e.g. The Awful Truth, The Daily Show) and one that moves away from the sometimes too simplistic binary discourses that have tended to become characteristic of recent debates over `tabloidization'.
The legitimacy and moral authority of the National News Council (USA)
Authors: Ugland Erik
Published: April 2008

As an institution designed to resolve disputes between the public and the American news media and to assess the ethical standards of the mainstream media, the National News Council (1973-84) was, at least in the USA, a ground-breaking institution. This study suggests, however, that the Council's work was anything but revolutionary, and that it probably did more to entrench the received tenets of American journalism than to either validate or refashion them. By applying a conventional set of ethical standards in its resolution of disputes, by repeatedly emphasizing the First Amendment rights of the media respondents, by violating its by-laws and allowing the media members of the Council to dominate its membership, and by ruling in the vast majority of cases against the public complainants, the Council's work provides grist for those who might question its legitimacy and its value as a model of authentic press-public collaboration.
Normative navigation in the news media
Authors: Bro Peter
Published: April 2008

Past models of norms in news reporting have been characterized by the particular geographical and historical, practical and theoretical context from which they have been constructed. This has limited their interdisciplinary applicability and, in the light of normative developments in recent years, it has become increasingly clear that we need a more contemporary explanatory model to capture current developments on both sides of the Atlantic. Such a normative model - drawing on the dichotomies of active or passive journalism, and deliberative or representative journalism - is introduced in this article. This model can be used as an analytical tool by researchers and as an operational tool by news providers with a need for a normative navigation instrument, and as such it may help create or reshape a common culture between two increasingly interrelated professions: news reporters and researchers.
Theological Education in Africa in the Post-1998 Lambeth Conference
Authors: Galgalo Joseph D. , Mombo Esther
Published: April 2008

Since 1998 there has been a revived interest in theology among Anglicans around the world. Rowan Williams has encouraged this with the promotion of a Theological Education for the Anglican Communion Commission. The Global South primates have called for a rejection of the Western paradigm of Anglican theology in the context of the current debates about sexuality. The key Lambeth resolution on sexuality at the 1998 conference carries with it significant assumptions and challenges about theological method. There has been a renewed focus on context in doing theology. These changes can be seen in the case of Kenya where there has been a determined effort to re-cast the theological curriculum. Theology has also become more popular among lay people and theological work is expanding and flourishing.
Wear resistance and damping capacity of semisolid processed hypoeutectic grey cast iron
Authors: Ramadan M. , Nomura H. , Takita M.
Published: April 2008

The wear resistance and damping capacity of hypoeutectic grey cast iron (carbon equivalent =3·59%) were investigated as a function of the relative amount of primary fraction of solid. In the present study the authors have used a cooling plate to produce semisolid iron slurry. Sand mould castings with 14 mm strip thickness were used in the present study. For comparison, damping capacity was also carried out on ordinary ductile iron specimen made from Y block with 15 mm thickness. The wear resistance of grey cast iron was improved using the semisolid processing. The wear rate of grey iron decreases as the fraction of solid increases until 0·12. Further increase of fraction of solid increases the wear rate due to formation of interconnected fine graphite type D. Frictional wear mechanism of iron casting is strongly affected by shape, size and arrangement of graphite precipitates. For semisolid casting at high loading, increasing the sliding speed increases the rate of oxidation and consequently changes the wear mechanism. The damping capacity of semisolid grey cast iron is lower than ordinary grey iron but higher than ductile iron for all strain amplitude ranges. The damping capacity of both ordinary and semisolid grey cast iron increases with strain amplitude.
Inhomogeneous deformation in metallic glasses
Authors: Zhang Y.
Published: April 2008

In metallic glasses, the combination of metallic bonding with an amorphous structure gives excellent mechanical properties such as high yield stress and yield strain compared with conventional polycrystalline alloys. It is, therefore, of great interest to exploit bulk metallic glasses (BMGs) as structural materials, particularly as many are now available in bulk form. The plastic deformation of BMGs is generally inhomogeneous, severely localised into shear bands with a characteristic thickness of only ∼10 nm. This shear instability is associated with work softening and impedes the exploitation of the otherwise desirable mechanical properties of metallic glasses in structural applications. Recent progress in understanding work softening in metallic glasses and the consequent formation of shear bands is reviewed, considering both experimental work and molecular dynamics simulations. The basic phenomena of plastic deformation in BMGs are briefly introduced. The initiation of shear bands, their propagation, and associated structural changes within the bands are considered. Recent advances in tailoring the microstructure of metallic glasses to increase their plasticity are also presented. The mechanisms of forming shear bands in different material systems are compared, highlighting the distinct plastic deformation mechanisms in BMGs.
Effect of extrusion parameters on microstructure and mechanical properties of ZK30 Mg Alloy
Authors:   Govind, Nair K. S. , Mittal M. C. , Sikand R. , Gupta A. K.
Published: April 2008

Mg alloys are the lightest structural metallic materials, and are very attractive for aerospace applications. But their applications are limited owing to their poor workability, moderate strength and poor corrosion resistance. ZK30 Mg alloy (Mg–3·0Zn–0·5Zr (wt-%)) shows better strength and workability due to the presence of fine grains than conventional Mg–Al–Zn base wrought alloys. In the present study homogenised billets of this alloy were extruded into square tubes at various temperatures and ram speeds to determine the regime of uniform deformation and best mechanical properties. Material exhibited dynamic recrystallisation under all the conditions studied. Increase in the extrusion temperature improves the homogeneity of deformation but further increase in temperature (>400°C) causes abnormal grain growth. Increase in ram speed is also found to enhance uniform deformation but further increase in ram speed (>8 mm s−1) causes adiabatic heating and flow localisation. Based on the findings of the present study, an optimum process parameter regime was finalised for homogeneous deformation and best mechanical properties.
Characterisation of thin section dissimilar weld joint comprising austenitic and ferritic stainless steels
Authors: Bala Srinivasan P. , Satish Kumar M. P.
Published: April 2008

Autogenous gas tungsten arc welding to produce a dissimilar weld comprising austenitic and ferritic stainless steels was attempted. Defect free welds with over matching mechanical properties could be accomplished with a resultant weld metal consisting of a dual phase structure (ferrite and austenite). The pitting corrosion behaviour of the weld metal/heat affected zone, assessed as a ‘composite zone’, was found to be inferior to the rest of the regions in this dissimilar weldment, in both the acidic and neutral chloride solutions of different concentrations.
Investigation of tensile strength of hydroxyapatite with various porosities by diametral strength test
Authors: Evis Z. , Ozturk F.
Published: April 2008

It is appropriate to administer the diametral test to biomedical materials used in dental applications because stresses formed on dental implants are similar to those that formed in this test. To show this similarity, an experimental study of diametral strength testing of hydroxyapatite was performed. The influence of porosity on hydroxyapatite was investigated experimentally to determine how the diametral strength was affected. Hydroxyapatite was air sintered at 1100°C for 1 h with porosities ranging from 1 to 32%. The results indicated that hydroxyapatite with improved densification had higher diametral strength values. X-ray diffraction analysis showed that sintered samples were pure hydroxyapatite.
Effect of complexing agents on properties of electroless Ni–P deposits
Authors: Cheng Y. H. , Zou Y. , Cheng L. , Liu W.
Published: April 2008

In the present study, the authors studied the effect of complexing agents on the formation and properties of electroless Ni–P coatings having high phosphorus. The experimental results indicated that the composition of Ni–P deposits was decided mainly by main salt (nickel sulphate) and reducing agent (sodium hypophosphite), the amount of complexing agents did not have important influence on phosphorus content. However, the amount of complexing agents could affect the surface morphology, plating rate and microstructure of electroless Ni–P deposits. By adjusting the complexing agents in plating bath, the high phosphorus (11–12 wt-%)Ni–P coatings consisting of almost fully amorphous phase or the mixture of amorphous and nanocrystalline phase could be obtained. The possible reason of forming nanocrystalline phase was explained through the concentration fluctuation causing by lots of complexing agents. The formation of nanocrystalline phase not only increased the hardness of electroless Ni–P deposits, but also improved the thermal stability.
Prediction of effective elastic modulus of plain weave multiphase and multilayer silicon carbide ceramic matrix composite
Authors: Xu Y. J. , Zhang W. H. , Wang H. B.
Published: April 2008

The bottom up multiscale finite element modelling that is based on the sequential consideration of the fibre/interface/matrix scale and the tow/matrix/coat scale is employed to predict the effective elastic modulus of the plain wave multiphase and multilayer silicon carbide ceramic matrix composite. Instead of using the homogenisation method, the strain energy based method that is advantageous in computing efficiency and numerical implementation is adopted for the multiscale analysis and evaluation of effective properties. First, the effective properties of tows are computed on the fibre/interface/matrix scale. They are then incorporated into the tow/matrix/coat scale to evaluate the effective properties of the composite. Numerical results obtained by the proposed method and model show a good agreement with the results measured experimentally.
Using carbon nanotubes to enhance creep performance of lead free solder
Authors: Nai S. M. L. , Wei J. , Gupta M.
Published: April 2008

In the present study, the influence of multiwalled carbon nanotubes (CNTs) on the creep performance of 95·8Sn–3·5Ag–0·7Cu lead free solder is investigated. Composite solders containing varying weight percentages of CNTs were synthesised. Solder joints were fabricated and subjected to a series of tests under testing temperatures ranging from 25 to 125°C and applied stresses ranging from 4 to 18 MPa. Creep results revealed that solders containing CNTs exhibited significantly improved creep resistance and also creep time to failure increased. Stress exponents of composite solders were higher than that of monolithic solder. In general, stress exponent was found to increase with increasing applied stress and with decreasing testing temperature. The range of activation energies of composite solder with 0·01 wt-%CNT addition was found to be comparable to that of monolithic Sn–Ag–Cu. However, as the amount of CNT increased to 0·04 wt-%, the range of activation energies increased accordingly.
Analysis of machining of laser hardened M42 tool steel using computational techniques
Authors: Jackson M. J. , Whitfield M. D.
Published: April 2008

The mutual interactions between M42 tool steel and a multipoint cutting tool creates significant opportunities to understand how dry milling of laser hardened materials affects machining conditions especially at the microscale. The present work not only compares various computational approaches to the solution of shear plane and tool face temperatures during dry machining, but also discusses how the accompanying machining attributes react to large changes in the coefficient of friction caused by changes in the type of coated cutting tool used for machining in the form of changes in the coefficient of sliding friction. The paper accounts for the changes in material properties during machining as a function of increasing temperature and also shows how stresses and strains are affected by significant changes in the magnitude of the coefficient of friction.
Irreversible thermodynamics modelling of plastic deformation of metals
Authors: Huang M. , Rivera-Díaz-del-Castillo P. E. J. , Bouaziz O. , van der Zwaag S.
Published: April 2008

Irreversible thermodynamics is employed to describe plastic deformation of metallic single crystals and coarse grained polycrystals. Dislocations are assumed to increase the crystal entropy via processes of dislocation generation, glide and annihilation. It is postulated that the entropy progresses according to the relationship d S/d γ= κ( C/T)d τ/d γ, where S is the entropy of the deformed metal, γ is the shear strain, κ is a scaling factor measuring the average distance between dislocations, C is a material dependent constant, T is the absolute temperature and τ is the shear stress. A succinct expression for dislocation evolution is obtained; it is qualitatively similar to that proposed by Kocks and Mecking ( Prog. Mater. Sci., 2003, 48, 171–273) on a phenomenological basis. The model is applied to the description of the deformation behaviour of Cu and Al with good results.
Weld microstructure and shape of laser–arc hybrid welding
Authors: Gao M. , Zeng X. Y. , Hu Q. W. , Yan J.
Published: April 2008

A series of CO2 laser–metal inert gas arc hybrid welding experiment was carried out to investigate the effects of laser/arc energy ratio and groove parameters on the shape and microstructure of hybrid weld. The results showed that increasing arc current and groove cross-section area can reduce dimension difference of laser zone and arc zone by enhancing the uniform of energy distribution in molten pool. The arc current can speed the melted metal flow to the pool root and drive more heat to the pool below by the arc pressure, and groove area can reduce the resistance of melted metal flowing to the pool root. The microstructure of hybrid weld is simultaneously determined by the total line energy of hybrid welding and energy ratio of laser/arc ( ER LA), and only under the proper or relatively smaller total line energy ER LA has obvious effects on microstructure. Increasing the ER LA can increase the tendency of hybrid weld to obtain structure with higher hardness. Furthermore, the mechanical performance of the hybrid weld with lower ER LA is good.
Effect of welding consumables on tensile and impact properties of shielded metal arc welded high strength, quenched and tempered steel joints
Authors: Magudeeswaran G. , Balasubramanian V. , Balasubramanian T. S. , Reddy G. Madhusudhan
Published: April 2008

Quenched and tempered (Q&T) steels are widely used in the construction of military vehicles due to its high strength to weight ratio and high hardness. These steels are prone to hydrogen induced cracking in the heat affected zone (HAZ) after welding and HAZ softening. The use of austenitic stainless steel (ASS) consumables to weld the above steel was the only remedy because of higher solubility for hydrogen in austenitic phase. Recent studies proved that high nickel steel (HNS) and low hydrogen ferritic (LHF) steel consumables can be used to weld Q&T steels, which can give very low hydrogen levels in the weld deposits. In this investigation an attempt has been made to study the effect of welding consumables on tensile and impact properties of high strength, Q&T steel joints. Three different consumables, namely ASS, LHF steel and HNS have been used to fabricate the joints by shielded metal arc welding (SMAW) process. The joints fabricated using LHF steel electrodes showed superior transverse tensile properties than other joints. The joints fabricated using HNS electrodes exhibited better impact properties than other joints. The joints fabricated by LHF steel electrodes exhibited lesser degree of HAZ softening, while HNS joints exhibited the maximum HAZ softening due to the difference in weld thermal cycle.
Influence of deceleration phase on properties of friction welded pipelines using intermediate ring
Authors: Faes K. , Dhooge A. , de Baets P. , Afschrift P.
Published: April 2008

A new welding method for fully automatic welding of pipelines has been developed. The proposed welding procedure is a new variant of the well known friction welding process. An intermediate ring is rotated in between the pipes to be welded to generate the required heat to realise the weld. In the first part of the present paper, the working principles of the new welding process are briefly described. Since a literature survey revealed that the deceleration phase has an influence on the mechanical properties and heat affected zone microstructure of friction welds, the enhancement of the mechanical properties by controlling the deceleration was investigated for the welding process. The influence of the deceleration phase on the properties of the welds is discussed. The pipes used were 3 in. pipes (outer diameter: 88˙9 mm) with a wall thickness of 7˙6 mm, made of the pipeline steel API-5L X42. Three welding ring materials were used: a thermomechanically rolled steel, a quenched and tempered steel and a normalised fine grained steel. The parameters studied were the duration of the deceleration and the rotation speed at which forging is performed.
Laser welding of zinc coated steel: An alternative to resistance spot welding
Authors: Dasgupta A. K. , Mazumder J.
Published: April 2008

Laser lap welding of zinc coated steel using copper is found to be a promising alternative to resistance spot welding. Copper, which acts as an alloying element for zinc, is sandwiched between the lapped sheets in powder form. Such introduction of copper not only ensures a zero gap, but also assists in reducing violent vaporisation of zinc, the main cause of porosity and spattering during laser welding of zinc coated steel. Emission spectroscopy data recorded during the welding experiments validate the effect of copper on zinc vaporisation. Mechanical tests show acceptable results for laser welds made with copper. Moreover, minimal residual copper in the weld zone, and its extended solid solubility in iron due to non-equilibrium processing rules out the possibility of hot cracking. Concerns regarding electrochemical corrosion due to addition of copper in the weld are addressed and the results are found to be favourable. It is further shown that the fatigue life of a laser weld is ∼25% higher than a standardised spot weld for the same strain energy release rate. Finally, an equivalent laser weld specification is given for the zinc coated steel used in this study.
Method for predicting risk of cracking during weld repair of heat resistant cast steels
Authors: Duchosal A. , Deschaux-Beaume F. , Bordreuil C. , Fras G. , Lours P.
Published: April 2008

Owing to their low ductility at room temperature, heat resistant cast austenitic stainless steels are very sensitive to weld cracking. Cracks are formed in brittle zones of the heterogeneous microstructure constituted by the carbide rich interdendritic spaces. In order to identify the operating factors affecting the cracking propensity of such steels during welding, a three step method, based on numerical simulation, is presented. First, the macroscopic temperature and stress fields are determined by a finite element calculation, considering a homogeneous material. In a second step, a localisation criterion is defined to identify critical zones, according to the macroscopic fields determined in the first step. Then, the heterogeneous microstructure of the cast steel is modelled in a ‘representative cell’, and the thermomechanical history of the critical zone previously identified is applied as boundary condition, in order to determine the local stress field. The cracking is then supposed to occur when the maximal principal stress in the interdendritic zone of the representative cell reaches the cleavage stress of the carbides, determined using SEM in situ tensile tests. This method is used to predict cracking during multipass weld repair of bulk samples, under various welding conditions. A comparison is carried out between experiment and simulation to validate the method.
Improvement of mechanical properties of aluminium–copper alloy (AA2219) GTA welds by Sc addition
Authors: Seshagiri P. C. , Nair B. S. , Reddy G. M. , Rao K. S. , Bhattacharya S. S. , Rao K. P.
Published: April 2008

Aluminium alloy AA2219 is a high strength alloy widely used for aerospace application. One of the drawbacks of most of the high strength aluminium alloys is that they suffer from poor weldability. However, AA2219 is an exception due to the presence of more copper that helps in healing cracks by providing extra eutectics. Although AA2219 has excellent weldability, the strength of a welded joint is only 35–45% of the base metal. The loss of strength is due to the dissolution of the strengthening precipitates during melting. Therefore, there is a need to improve the fusion zone strength of AA2219 welds. In this study, an attempt was made experimentally to use different gas tungsten arc welding (GTAW) techniques and modify the filler chemistry with addition of scandium (Sc) and zirconium (Zr) in order to improve the mechanical properties of the AA2219 weld joints. The application of the GTAW DCEN with Sc and Zr to the filler wire proved to be the most economical and perhaps the optimal choice for welding AA2219 aluminium alloys. Addition of Sc and Zr to the fusion zone during welding enhanced grain refinement in the GTAW welds leading to better mechanical properties when compared to welding with conventional AA2319 filler.
Residual stresses in resistance spot welded steel joints
Authors: Khanna S. K. , Long X.
Published: April 2008

Residual stresses in spot welded joints play an important role in affecting the durability of the joint. This paper reviews the numerical models used to predict the spatial and temporal generation of residual stresses and the experimental measurements to investigate the state of such stresses in spot welded steel sheets. The effect of residual stress on the fatigue strength of a spot welded joint has also been presented. Factors and methods that can favourably change the residual stress distribution in a spot welded joint to improve its fatigue strength have been summarised.
The usefulness of twenty-four molecular markers in predicting treatment outcome with combination therapy of amodiaquine plus sulphadoxine-pyrimethamine against falciparum malaria in Papua New Guinea
Authors: Marfurt Jutta , Müller Ivo , Sie Albert , Oa Olive , Reeder John C , Smith Thomas A , Beck Hans-Peter , Genton Blaise
Published: April 2008

Background

In Papua New Guinea (PNG), combination therapy with amodiaquine (AQ) or chloroquine (CQ) plus sulphadoxine-pyrimethamine (SP) was introduced as first-line treatment against uncomplicated malaria in 2000.

Methods

We assessed in vivo treatment failure rates with AQ+SP in two different areas in PNG and twenty-four molecular drug resistance markers of Plasmodium falciparum were characterized in pre-treatment samples. The aim of the study was to investigate the association between infecting genotype and treatment response in order to identify useful predictors of treatment failure with AQ+SP.

Results

In 2004, Day-28 treatment failure rates for AQ+SP were 29% in the Karimui and 19% in the South Wosera area, respectively. The strongest independent predictors for treatment failure with AQ+SP were pfmdr1 N86Y (OR = 7.87, p < 0.01) and pfdhps A437G (OR = 3.44, p < 0.01). Mutations found in CQ/AQ related markers pfcrt K76T, A220S, N326D, and I356L did not help to increase the predictive value, the most likely reason being that these mutations reached almost fixed levels. Though mutations in SP related markers pfdhfr S108N and C59R were not associated with treatment failure, they increased the predictive value of pfdhps A437G. The difference in treatment failure rate in the two sites was reflected in the corresponding genetic profile of the parasite populations, with significant differences seen in the allele frequencies of mutant pfmdr1 N86Y, pfmdr1 Y184F, pfcrt A220S, and pfdhps A437G.

Conclusion

The study provides evidence for high levels of resistance to the combination regimen of AQ+SP in PNG and indicates which of the many molecular markers analysed are useful for the monitoring of parasite resistance to combinations with AQ+SP.
Sensing applications of micro- and nanoelectromechanical resonators
Authors: Niebelschütz F , Cimalla V , Brückner K , Stephan R , Tonisch K , Hein M A , Ambacher O
Published: April 2008

The sensitivity of micro- and nanoscale resonator beams for sensing applications in ambient conditions was investigated. Micro-electromechanical (MEMS) and nanoelectromechanical systems (NEMS) were realized using silicon carbide (SiC) and polycrystalline aluminium nitride (AlN) as active layers on silicon substrates. Resonant frequencies and quality factors in vacuum as well as in air were measured. The sensitivity behaviour under ambient conditions with a mass loading in the range of picogram (pg) was verified and measurements with biological mass loading were performed. In addition, the sensitivity to pressure variations was analysed.
Superhydrophobic surfaces by dynamic nanomasking and deep reactive ion etching
Authors: Song Ying , Zou Min
Published: April 2008

This paper reports a study on fabricating superhydrophobic surfaces with micro- and nanohierarchical topography by dynamic nanomasking (DNM) and deep reactive ion etching (DRIE). In this study, thin layers of gold (Au) were sputtered on silicon (Si) wafers followed by annealing the samples in a conventional furnace to break the thin films into Au nanoparticles attached to the Si surfaces. These randomly distributed nanoparticles served as dynamic nanomasks during DRIE processes, in which sulphur hexafluoride (SF6) and octofluorocyclobutane (C4F8) were used as etching and polymerization gases, respectively. Surface topography and wetting properties of the samples were characterized by scanning electron microscopy (SEM) and a video-based optical contact angle meter (VOCAM). SEM images show that this technique created micro-sized craters with Au nanoparticles residing on the ridges of the microstructures. The largest water contact angle (WCA) obtained by this method is about 163°. The surface superhydrophobicity is attributed to the combination of micro- and nano-hierarchical topography and surface polymerization.
Synthesis and Properties of Novel Oligodeoxynucleotides Containing 6,3′-Methanodeoxyuridine
Authors: Moriguchi Tomohisa , Yamato Fumisada , Shinozuka Kazuo
Published: April 2008

This paper deals with the synthesis and properties of novel oligodeoxynucleotide containing 6,3′-methanodeoxyuridine which is connected between C-6 of pyrimidine base and C-3′ of deoxyribose by a methylene group. The modified base was successfully introduced into the oligodeoxynucleotide by the standard method. The modified oligodeoxynucleotide formed the less stable duplex with both complementary DNA and RNA. The CD spectra indicated that the duplex formed the noncanonical duplex structure distinct from the A-form or B-form structure.