bluuebunny/crossref_metadata_2025 huggingface dataset:
Switching from long-term benzodiazepine therapy to pregabalin in patients with generalized anxiety disorder: a double-blind, placebo-controlled trial
Authors: Hadley Sallie J , Mandel Francine S , Schweizer Edward
Published: June 2011

To evaluate the efficacy of pregabalin in facilitating taper off chronic benzodiazepines, outpatients ( N = 106) with a lifetime diagnosis of generalized anxiety disorder (current diagnosis could be subthreshold) who had been treated with a benzodiazepine for 8–52 weeks were stabilized for 2–4 weeks on alprazolam in the range of 1–4 mg/day. Patients were then randomized to 12 weeks of double-blind treatment with either pregabalin 300–600 mg/day or placebo while undergoing a gradual benzodiazepine taper at a rate of 25% per week, followed by a 6-week benzodiazepine-free phase during which they continued double-blind study treatment. Outcome measures included ability to remain benzodiazepine-free (primary) as well as changes in Hamilton Anxiety Rating Scale (HAM)-A and Physician Withdrawal Checklist (PWC). At endpoint, a non-significant higher proportion of patients remained benzodiazepine-free receiving pregabalin compared with placebo (51.4% vs 37.0%). Treatment with pregabalin was associated with significantly greater endpoint reduction in the HAM-A total score versus placebo (−2.5 vs +1.3; p < 0.001), and lower endpoint mean PWC scores (6.5 vs 10.3; p = 0.012). Thirty patients (53%) in the pregabalin group and 19 patients (37%) in the placebo group completed the study, reducing the power to detect a significant difference on the primary outcome. The results on the anxiety and withdrawal severity measures suggest that switching to pregabalin may be a safe and effective method for discontinuing long-term benzodiazepine therapy.
Clinically unintended medication switches and inability to prescribe preferred medications under Medicare Part D
Authors: West Joyce C , Rae Donald S , Mojtabai Ramin , Rubio-Stipec Maritza , Kreyenbuhl Julie A , Alter Carol L , Crystal Stephen
Published: June 2011

Medicare Part D has expanded medication access; however, there is some evidence that dually eligible psychiatric patients have experienced medication access problems. The aim of this study was to characterize medication switches and access problems for dually eligible psychiatric patients and associations with adverse events, including emergency department visits, hospitalizations, homelessness, and incarceration. Reports on 986 systematically sampled, dually eligible patients were obtained from a random sample of practicing psychiatrists. A total of 27.6% of previously stable patients had to switch medications because clinically indicated and preferred refills were not covered or approved. An additional 14.0% were unable to have clinically indicated/preferred medications prescribed because of drug coverage/approval. Adjusting for case-mix, switched patients ( p = 0.0009) and patients with problems obtaining clinically indicated medications ( p = 0.0004) had significantly higher adverse event rates. Patients at greatest risk were prescribed a medication in a different class or could not be prescribed clinically-indicated atypical antipsychotics, other antidepressants, mood stabilizers, or stimulants. Patients with problems obtaining clinically preferred/indicated antipsychotics had a 17.6 times increased odds ( p = 0.0039) of adverse events. These findings call for caution in medication switches for stable patients and support prescription drug policies promoting access to clinically indicated medications and continuity for clinically stable patients.
Relaxin polymorphisms associated with metabolic disturbance in patients treated with antipsychotics
Authors: Munro Janet , Skrobot Olivia , Sanyoura May , Kay Victoria , Susce Margaret T , Glaser Paul EA , de Leon Jose , Blakemore Alexandra IF , Arranz Maria J
Published: June 2011

People with schizophrenia have an increased risk of metabolic syndrome, with consequent elevated morbidity and mortality, largely due to cardiovascular disease. Metabolic disorders comprise obesity, dyslipidemia and elevated levels of triglycerides, hypertension, and disturbed insulin and glucose metabolism. The elevated risk of metabolic syndrome in individuals suffering from schizophrenia is believed to be multifactorial, related to a genetic predisposition, lifestyle characteristics and treatment with antipsychotic medications. Relaxin 3 (RLN3, also known as INSL7) is a recently identified member of the insulin/relaxin superfamily that plays a role in the regulation of appetite and body weight control. RLN3 stimulates relaxin-3 receptor 1 (relaxin/insulin-like family peptide receptor 3, RXFP3) and relaxin receptor 2 (relaxin/insulin-like family peptide receptor 4, RXFP4). We have investigated the role of ten polymorphisms in these genes ( RLN3 rs12327666, rs1982632, and rs7249702, RLN3R1 rs42868, rs6861957, rs7702361, and rs35399, and RLN3R2 rs11264422, rs1018730 and rs12124383) in the occurrence of metabolic syndrome phenotypes (obesity, diabetes, hypercholesterolemia, hypertrigyceridemia, and hypertension) in a cross-sectional cohort of 419 US Caucasian patients treated with antipsychotic drugs. We found several associations between relaxin polymorphisms and hypecholesterolemia, obesity and diabetes, suggesting a role for the relaxin/insulin pathway in the development of metabolic disturbance observed in patients treated with antipsychotics.
Adaptive compression for 3D laser data
Authors: Smith Mike , Posner Ingmar , Newman Paul
Published: June 2011

This paper concerns the creation of efficient surface representations from laser point clouds created by a push broom laser system. We produce a continuous, implicit, non-parametric and non-stationary representation with an update time that is constant. This allows us to form predictions of the underlying workspace surfaces at arbitrary locations and densities. The algorithm places no restriction on the complexity of the surfaces and automatically prunes redundant data via an information theoretic criterion. This criterion makes the use of Gaussian Process Regression a natural choice. We adopt a formulation which handles the typical non-functional relation between XY location and elevation allowing us to map arbitrary environments. Results are presented that use real and synthetic data to analyse the trade-off between compression rate and reconstruction error. We attain decimation factors in excess of two orders of magnitude without significant degradation in fidelity.
Design and optimization strategies for muscle-like direct-drive linear permanent-magnet motors
Authors: Ruddy Bryan P , Hunter Ian W
Published: June 2011

We report a new approach to the design of direct-drive linear permanent-magnet motors for use in general-purpose robotic actuation, with particular attention to applications in bird-scale flapping-wing robots. We show a simple, quantitative analytical modeling framework for this class of actuators, and demonstrate inherent scaling properties that allow the production of motors with force densities and efficiencies comparable to those of biological muscles. We illustrate the effectiveness of our model with finite-element analysis and a comparison with commercially available motors, and discuss future plans for experimental validation. We show how this model leads to a set of practical design specifications for muscle-like motors, and examine the resulting trade-off between thermal management and motor fabrication complexity.
Sampling-based algorithms for optimal motion planning
Authors: Karaman Sertac , Frazzoli Emilio
Published: June 2011

During the last decade, sampling-based path planning algorithms, such as probabilistic roadmaps (PRM) and rapidly exploring random trees (RRT), have been shown to work well in practice and possess theoretical guarantees such as probabilistic completeness. However, little effort has been devoted to the formal analysis of the quality of the solution returned by such algorithms, e.g. as a function of the number of samples. The purpose of this paper is to fill this gap, by rigorously analyzing the asymptotic behavior of the cost of the solution returned by stochastic sampling-based algorithms as the number of samples increases. A number of negative results are provided, characterizing existing algorithms, e.g. showing that, under mild technical conditions, the cost of the solution returned by broadly used sampling-based algorithms converges almost surely to a non-optimal value. The main contribution of the paper is the introduction of new algorithms, namely, PRM* and RRT* , which are provably asymptotically optimal, i.e. such that the cost of the returned solution converges almost surely to the optimum. Moreover, it is shown that the computational complexity of the new algorithms is within a constant factor of that of their probabilistically complete (but not asymptotically optimal) counterparts. The analysis in this paper hinges on novel connections between stochastic sampling-based path planning algorithms and the theory of random geometric graphs.
What postcolonial theory doesn’t say
Authors: Lazarus Neil
Published: June 2011

This article proposes that there is a category error at the heart of ‘postcolonial studies’ as an academic field. There has been a notable failure in the field to situate the historical projects of colonialism and imperialism in the determinant contexts of the inception, consolidation and development of the modern world system, whose developmental logic is that of combined and uneven development. Even on the best postcolonialist accounts, imperialism is typically situated in civilisational terms and refers to ‘the West’ rather than to capitalism. The social and temporal power identified through this means is a euphemism. The idea of ‘the West’, as it is deployed in postcolonial studies, inevitably issues in a dematerialised — and, for that matter, unhistorical — understanding of the forces powering the world system over the course of the past 500 years. This case is argued through reviewing work by Edward Said, Andre Gunder Frank, Benita Parry, Fredric Jameson, Susan Bassnett, V. Y. Mudimbe, Rey Chow and novelists such as Ngugi wa Thiong’o and Ousmane Sembène, inter alia.
The end of Swedish exceptionalism? Citizenship, neoliberalism and the politics of exclusion
Authors: Schierup Carl-Ulrik , Ålund Aleksandra
Published: June 2011

Sweden, where some 20 per cent of the population is either foreign born or second generation, has long been known internationally as the model of a tolerant, egalitarian, multicultural welfare state, which extended substantial citizenship, welfare and labour rights to all within its borders, including immigrants. However, under the twin pressures of neoliberalism and the EU’s commitment to ‘managed migration’, this Swedish exceptionalism has been, and continues to be, substantially eroded. The shortcomings of the earlier multicultural settlement of the 1960s and 1970s, a growing extremist populism, the growth of an unprotected, semi-clandestine sector of the labour market, combined with high levels of youth unemployment and urban segregation, have led to unprecedented rioting and violence in Swedish cities. The voices of minority ethnic youth, many of them Muslim, should be heeded as rejecting the exclusivism of current political trends.
The shaping of Islam and Islamophobia in Belgium
Authors: Zemni Sami
Published: June 2011

The author discusses the way in which Islam has been cast as a political problem in Belgium and how Muslims have, particularly in Flanders, become framed by politicians and commentators in the media as a threat. The actual socioeconomic difficulties that Muslims (particularly those of Turkish and Moroccan descent) face are being redrawn as problems stemming from their culture and religion. State agencies are trying to shape the political organisation that will represent Belgian Muslims, as the issue of Islam is increasingly debated in terms of the ‘clash of civilisations’, and secularism and the Enlightenment are linked in public debate with a Christian Europe.
Latin American cleaners fight for survival: lessons for migrant activism
Authors: Hearn Julie , Bergos Monica
Published: June 2011

This article documents the significant successes and major setbacks of a campaign led by Latin American cleaners for union recognition and better pay and conditions at the University of London. It shows how they overcame fear, resignation, intimidation, racism, poverty and cultural and linguistic alienation to find their political agency. However, their collective empowerment was met by dismissals and deportations. The article argues that there are a number of important lessons for the trade union movement to learn; namely, the need to have specific legal and campaigning strategies in place to defend its migrant activists as well as calling for the regularisation of ‘irregular’ workers. In sum, the struggle for immigrant rights is at the cutting edge of the global working-class fightback.1
From emigrant Spain to immigrant Spain
Authors: Arocena Felipe
Published: June 2011

Spain is undergoing a process of intense demographic change towards a more diverse society brought about by massive immigration over the last decade that includes a high proportion of Latin Americans. Pejoratively dubbed ‘sudacas’, they are moving in the opposite direction to the Spanish who went to Latin America 100 years ago. Multicultural Spain has two main facets: the historical regional minorities in Catalonia, Galicia and the Basque Country, elements of which have waged struggles for national autonomy; and the recent immigrant minorities, notably the Latin Americans, North Africans and Romanians.
David Edgar’s Testing the Echo
Authors: Reinelt Janelle , Hewitt Gerald
Published: June 2011

David Edgar is Britain’s leading anti-racist playwright and a prominent commentator. His contribution as a political writer and public social critic has been analysed by Janelle Reinelt and Gerald Hewitt in their forthcoming book, The Political Theatre of David Edgar: negotiation and retrieval (Cambridge University Press, 2011). The piece below is based on excerpts that focus on Testing the Echo, a recent play on Britishness by Edgar.
UK: racial violence and the night-time economy
Authors: Burnett Jon
Published: June 2011

This article examines the prevalence of racial violence in the UK’s night-time economy. Fifty-five racial attacks are documented over a six-month period, showing the risks faced by members of the public and workers at taxi firms, takeaways, convenience stores and service stations. It argues that flexible and highly casualised labour conditions, combined with increasing numbers of immigration raids, exacerbate the risk of racial violence.
Using the Level of Service Inventory-Revised to Improve Assessment and Treatment in Drug Court
Authors: Guastaferro Wendy P.
Published: June 2011

More than 2,000 drug courts in the United States provide supervision and substance-abuse treatment to thousands of offenders. Yet the treatment continuum from assessment to aftercare is underexplored. The effectiveness of the Level of Service Inventory–Revised (LSI-R) as a risk assessment tool is well established. However, fewer studies have considered its use in guiding treatment strategies. In using the LSI-R, the drug court program relied on the structured interview protocol (not the risk classification scores) to identify criminogenic needs that then helped determine placement in a high- or low-needs treatment track. To evaluate the effectiveness of these treatment placement decisions, this research used the LSI-R scores to examine individual and group differences ( N = 182). Significant and substantive differences at the individual and group levels were found thus providing empirical support for using the LSI-R as a link between assessment and treatment. Implications for developing standards and practice protocols for drug courts are discussed.
Aspiration problems for the Indian rural poor: Research on self-help groups and micro-finance
Authors: Morgan Jamie , Olsen Wendy
Published: June 2011

Our paper explores how poor rural households in India are increasingly accumulating debt through micro-finance initiatives channelled through local self-help groups (SHGs). The aim of micro-finance and SHGs is to provide a cheap source of capital for investment in self-sustaining economic practices — typified by the Velugu programme. However, the reality of micro-finance has been more complicated. It has created a class- and caste-related debt-dependency and vulnerability whilst also channelling poor households, and women in particular, into subordinate areas of the economy, which ultimately serve to maintain fundamental inequalities in Indian society. The initiatives may, in addition, be viewed as aspects of broader processes of financialisation.
From transition crisis to the global crisis: Twenty years of capitalism and labour in the Central and Eastern EU new member states
Authors: Onaran Özlem
Published: June 2011

This paper analyses the developments in wages, employment and income distribution in the Central and Eastern European new member states twenty years after transition to capitalism, divided into three periods: 1) the transition crisis; 2) post-transition growth; and 3) the crisis episode of 2008-9. Total employment has at best stagnated or slightly decreased. Modest wage increases have fallen behind productivity increases. Furthermore, the global crisis has led to employment losses in all countries, and real wages have already started to decrease in several countries.
The backward march of labour halted? Or, what is to be done with ‘union organising’? The cases of Britain and the USA
Authors: Gall Gregor , Fiorito Jack
Published: June 2011

This article evaluates the phenomenon and dynamics of union organising. It neither presents a critique of variants of union organising nor a preferred version of union organising as the solution. Rather, it provides some of the intellectual resources needed to create theoretically informed practice. It examines critiques of union organising to foreground discussion of the two key hallmarks of union organising to date; namely, officer domination and externally-led organising. This opens out the argument to consider a number of under-explored areas for the more expansive and ambitious version of union organising. Thereafter, it examines cross-cutting issues between the two countries and the absence of class consideration from union organising.
The TEKEL resistance movement: Reminiscences on class struggle
Authors: Özuğurlu Metin
Published: June 2011

This study presents some theoretical considerations of the TEKEL workers’ resistance movement in Turkey, focusing on four points. Those are: working-class formation in tension with identity formation; precariousness, which is examined by employing analytical distinctions between forms and modes of employment; the struggle for rights as a new pattern of class struggle; and the neoliberal citizenship regime, which implies sweeping labourers as a class away from the ‘political society’ in favour of engagement with their cultural identities.
The rising mafioso capitalists, opportunities, and the case of Turkey
Authors: Selçuk Fatma Ülkü
Published: June 2011

This article attempts to examine the mafiosi’s potential economic and political power with the help of two analytical tools: the mafioso mode of production, and mafioso capitalists. In evaluating the actual power of the mafiosi, the article presents empirical information on Turkey and other countries. It acknowledges that although the mafioso (capitalist) bosses hold the direct command of armed power, neither their antagonism nor their alliance with the conventional bourgeoisie can be essentialised. The results and prospects are evaluated in a way that stresses the need for a change in our worldviews in order to construct a more compassionate world.
Electronic governance and hybrid libraries in Namibia
Authors: Uutoni Wilhelm , Yule Wilson , Nengomasha Cathrine T.
Published: June 2011

A nation that is information empowered is capable of contributing to the democratic process. Governments are realizing more the importance of information and communication technologies (ICTs) as governing tools. Libraries have always been valued institutions within societies as trusted sources of information; and are becoming e-government access points relied on by both the patrons and government agencies (Jaeger and Fleischmann, 2007). They assist in finding information and some provide computer access and free Internet access. It is not surprising that with electronic governance (e-governance), libraries; in particular public libraries are expected to provide citizens with access and guidance in using e-government websites, forms and services. The paper is based on a study commissioned by International Federation of Library Associations and Institutions (IFLA) and carried out by the Department of Information and Communication Studies in 2009 on electronic governance and hybrid libraries in Africa. One of the study objectives was to investigate the existence and the role of hybrid libraries in e-governance in Africa. The study, which included a survey of several southern African countries and a case study of Namibia, employed the use of questionnaires for data collection. The paper focuses on the Namibian case study. The authors conclude that there is great potential for libraries to provide and promote e-governance but this is faced with many challenges, which include technological and human and financial resources.
Library assistants as situated learners: How they can learn more effectively
Authors: To Teresa
Published: June 2011

Many libraries are working hard to facilitate user learning, but in fact, staff learning is even more important. It is the staff members who implement plans and services, and it is their adaptability to the growing world that will directly affect the success and effectiveness of library functions. The staff are therefore expected to upgrade their knowledge and skills continuously in order to contribute and enhance the library’s roles and services in meeting the increasing user needs. This paper presents a research on Library Assistants (LA) as situated learners and how they learn in a university library in Hong Kong. LAs are core members of libraries and they often carry out a whole spectrum of duties and services that are indispensable. The most crucial target of this research is to explore, analyse and interpret the learning issue of the LAs and provide the administrators of the Library with some useful recommendations on how to facilitate a more effective learning environment for staff.
Operationalizing Management Citizenship Behavior and Testing Its Impact on Employee Commitment, Satisfaction, and Mental Health
Authors: Rubin Beth A. , Brody Charles J.
Published: June 2011

How can employers create conditions that foster satisfied, psychologically healthy, and committed employees? To answer that, the authors build on Hodson’s concept of management citizenship behavior (MCB). The authors incorporate managers’ ethical and family-supportive behaviors as essential components of MCB. The authors operationalize these constructs using data from the National Survey of the Changing Workforce. The study results demonstrate strong positive effects of MCB on employees’ commitment, job satisfaction, and mental health and support the inclusion of the additional components. This research contributes to the literature on worker attitudes and behaviors has clear implications for managers concerned with these enhancing the workplace.
Pain, Disability, and Depression in Osteoarthritis
Authors: Parmelee Patricia A. , Harralson Tina L. , McPherron Jesse A. , DeCoster Jamie , Schumacher H. Ralph
Published: June 2011

Objectives: A cross-sectional study examined how race and sex affect associations among osteoarthritis (OA) pain, disability, and depression in 363 older adults with diagnosed knee OA. Method: African American (Black; N = 94) and non-Hispanic White (White; N = 269) men and women self-reported pain, disability, depressive symptoms, arthritis history, general health, and demographic information. Results: Women experienced greater pain and marginally greater disability than men; African Americans reported greater disability and marginally greater pain than non-Hispanic Whites. These effects varied with education, health, and arthritis history. In ordinary least squares regression analyses, race and pain independently predicted depression. Significant interactions of race, sex, and disability were driven by a lack of relationship between depression and disability among African American men. Discussion: Race and sex influence affective response to OA pain and disability in complex ways, with African American men showing paradoxical effects. Further research is needed to elucidate mechanisms of this moderation effect.
Organizational Learning and Marketing Capability Development
Authors: Liu Gordon , Ko Wai-Wai
Published: June 2011

Social enterprise is a hybrid form of profit- and social benefit–seeking organization whereby traditional nonprofit organizations pursue both their social mission and business opportunities. To embrace this new strategic direction shift, the nonprofit organizations need to develop new competences that will enable them to respond to the changes in the business model. The article investigates the learning mechanisms through which social enterprises develop a marketing capability to deploy their resources in the marketplace as the drivers of competitive advantage in their commercial practice. We study eight cases of U.K.-based charity retailers to address the role of knowledge accumulation, articulation, and codification process in the evolution of marketing capability development. We identify, among other things, that the critical process of organizational learning for social enterprise is to transfer the experience into organization-specific knowledge under the social aspects of constraints.
State-Level Differences in Volunteerism in the United States
Authors: Rotolo Thomas , Wilson John
Published: June 2011

The volunteer rate in the United States varies from a high of 44% in Utah to a low of 18% in a bordering state, Nevada. Hierarchical nonlinear modeling techniques are used to test various theories such as demographic, institutional and cultural theory to explain general, religious, and secular volunteering with a nationally representative sample of nearly 300,000 respondents in 50 states. Household composition, race heterogeneity, and the density of nonprofit organizations influence the general volunteering rate. Religious volunteering is influenced by household composition, race heterogeneity, the density of religious congregations, and the religiosity of the residents of the state. The secular volunteer rate is influenced by household composition, race heterogeneity, and the density of nonprofit organizations.
Sequential imperfect preventive maintenance policy with random maintenance quality under reliability limit
Authors: Wang Z , Yang J , Wang G , Zhang G
Published: June 2011

To determine the optimal maintenance number for a system with random maintenance quality in infinite time horizon, a sequential imperfect preventive maintenance model considering reliability limit is proposed. The proposed model is derived from the combination of the Kijima type virtual age model and the failure rate adjustment model. Maintenance intervals of the proposed model are obtained through an iteration method when both failure rate increase factor and maintenance restoration factor are random variables with a uniform distribution. The optimal maintenance policy is presented by minimizing the long-run average cost rate. A real numerical example for the failures of numerical control equipment is given to demonstrate the proposed model. Finally, a discussion is presented to show how the optimal average cost rate depends on the different cost parameters. The results show that in order to satisfy the practical requirements of high reliability, it is necessary and worthwhile to consider the system's reliability limit in preventive maintenance practice.
Effect of rotational speeds on microstructure and mechanical properties of friction stir-welded 7075-T6 aluminium alloy
Authors: Rezaei H , Mirbeik M H , Bisadi H
Published: June 2011

In this article, effects of rotational speed on the microstructure and mechanical properties of friction stir-welded 7075-T6 Al alloys were investigated. Good correlation existed between the rotational speeds and weld properties. It was found that with increase in the rotational speed, higher pick temperatures and wider thickness of the heat-affected zone were obtained, and then grain coarsening, dissolution, and accumulation of hardening precipitates in grain boundaries. The average grain size of nugget increased from 6.8 to 8.9 µm, with increasing rotary speed from 600 to 1550 r/min. In addition, the best mechanical properties were obtained at moderate rotational speed of 825 r/min while ultimate tensile strength and elongation were 405 MPa and 6.1 per cent, respectively. Also, it was observed that at low welding speed of 60 mm/min, the weld properties are found to be dominated by the thermal cycle rather than the plastic deformation induced by tool, so as to make a reduction in hardness and strength of the weld when using higher rotational speeds.
Active steering of a tractor–semi-trailer
Authors: Odhams A M C , Roebuck R L , Jujnovich B A , Cebon D
Published: June 2011

This paper develops a path-following steering control strategy for an articulated heavy goods vehicle. The controller steers the axles of the semi-trailer so that its rear end follows the path of the fifth wheel coupling: for all paths and all speeds. This substantially improves low-speed manoeuvrability, off-tracking, and tyre scrubbing (wear). It also increases high-speed stability, reduces ‘rearward amplification’, and reduces the propensity to roll over in high-speed transient manoeuvres.

The design of a novel experimental heavy goods vehicle with three independent hydraulically actuated steering axles is presented. The path-following controller is tested on the experimental vehicle, at low and high speeds. The field test results are compared with vehicle simulations and found to agree well.

The benefits of this steering control approach are quantified. In a low-speed ‘roundabout’ manoeuvre, low-speed off-tracking was reduced by 73 per cent, from 4.25 m for a conventional vehicle to 1.15 m for the experimental vehicle; swept-path width was reduced by 2 m (28 per cent); peak scrubbing tyre forces were reduced by 83 per cent; and entry tail-swing was eliminated. In an 80 km/h lane-change manoeuvre, peak path error for the experimental vehicle was 33 per cent less than for the conventional vehicle, and rearward amplification of the trailer was 35 per cent less. Increasing the bandwidth of the steering actuators improved the high-speed dynamic performance of the vehicle, but at the expense of increased oil flow.
An empirical approach to predicting heat transfer within single- and twin-skin automotive exhaust systems
Authors: Bannister C D , Brace C J , Taylor J , Brooks T , Fraser N
Published: June 2011

This paper describes the further development of an exhaust system model based on the experimental characterization of heat transfer in a series of different pipe sections. Building on previous work published in this journal by the present authors, this study was undertaken to improve the operating range, accuracy, and usability of the original model as well as to introduce the ability to model twin-skin exhaust sections with an air gap.

Convective heat transfer relationships for nine stainless steel exhaust bend sections of various wall thicknesses and radii were experimentally characterized over a range of steady state conditions. In each case a correlation between the observed Reynolds number Re and the Nusselt number Nu was developed. Based on measured experimental data, a generic model was built using MATLAB/Simulink; this model is capable of predicting the relationship between the Nusselt number and the Reynolds number for previously unseen pipe geometries falling within the experimental design range. To develop the usefulness of the model further, 15 twin-skin test sections, intended to represent a range of geometries applicable to production automotive gasoline exhaust systems, were also fabricated and characterized. Within the model, both skins of each pipe section were split into five axial elements and five radial elements with the inner and outer skins linked via the modelling of free convection and radiation between them.

The predicted Reynolds–Nusselt relationships for each bend section and twin-skin configuration were validated using transient experimental data over a portion of the US06 drive cycle. The final model demonstrated an improved accuracy of exhaust gas temperature predictions, compared with the previous model iterations, with typical errors of less than ±1 per cent and a mean error over the US06 cycle of +0.2 per cent.
Space control law design in adaptive cruise control vehicles using model predictive control
Authors: Marzbanrad J , Karimian N
Published: June 2011

Driver assistance systems (DAS) are being broadly utilized in view of the fact that driver workloads will be decreased in DAS-equipped vehicles. A variety of DASs have been designed, and adaptive cruise control (ACC), as a type of DAS, is the subject of the present paper. The ACC designers’ main concerns are to provide comfort, which is characterized by minimized jerky movement and driver workload, and safety, which is characterized by the ACC system’s collision avoidance (CA) capability within its region of operation (determined on the basis of rigorous discussions derived from the relevant literature). Furthermore, ACC designers typically use more than one control law for ACC-equipped vehicles because the ACC must react differently to variations in driving conditions. In view of these points, it may be seen that, in utilizing ACC, the driver’s operating workload will be more that of a supervisor than an operator, owing to the longitudinal automation ability of ACC. In addition, an on-line control law can operate a vehicle in all driving conditions. The space control law developed in the current paper explains the compromise between safety and comfort.

ACC controllers are, typically, designed on two levels to increase the system capabilities: the upper level and the lower level. The upper-level controller comprises speed and space control laws, the latter of which computes the reference acceleration profile on the basis of the measured range, range-rate, and speed and acceleration of an ACC-equipped vehicle. Following reference acceleration, the desired range and range-rate will be achieved. The lower-level controller controls throttle and brake actuators to track the reference acceleration profile. In this paper, the desired acceleration in any time step is obtained by formulation of a constrained optimal control problem (QP) and employing a receding horizon control (RHC) strategy. Three baseline scenarios and the high-acceleration/deceleration driving cycle LA92 are considered to evaluate the control law. Note that the model predictive control (MPC) algorithm shows an advantage over other controllers in terms of safety and comfort. All working steps are executed using Matlab® software.
Axle whine phenomenon in light trucks: a combined numerical and experimental investigation
Authors: Koronias G , Theodossiades S , Rahnejat H , Saunders T
Published: June 2011

Axle whine is a continuous, steady state tonal sound, emitted from the differential unit’s hypoid gears. It is essentially induced by torque variations. This can be as a result of resonant conditions or torque fluctuations caused by engine order vibrations, compounded by gear transmission error. The principal mechanism of gear whine noise generation is, therefore, through transmission of vibration from the gear shafts and bearings to the differential housing, which is radiated as noise. Furthermore, interactions between the differential unit, axles and driveshafts often generate excessive tonal noises, which are the result of coupled bending and torsional resonances of assembled components. These resonances induce a magnification effect upon the noise source itself through exciting the gear shafts and distorting the alignment of the gear sets. Axle whine noise has become an important noise, vibration and harshness (NVH) concern, because of the nature of the noise; further compounded by the human aural system, which is highly sensitive in tonal memory. The result is continuously increasing warranty costs or use of expensive palliatives to mitigate the phenomenon. In this paper, a combined experimental and numerical investigation of axle whine in a rear-wheel-drive light truck is presented. The aim is to reveal some root causes of the drivetrain’s NVH behaviour, which can be related to the amplification/reduction of axle whine vibration and noise. Correlation of the experimental results with the vibration modes of the drivetrain has shown that for vehicle coasting conditions a number of modes are excited, which can interact with the vibrations of the hypoid gear pair. Finally, some light is shed on the role that differential bulk oil temperature plays in the severity of the ensuing vibration.
Robust control for the air path of a downsized engine
Authors: Colin G , Chamaillard Y , Bellicaud B
Published: June 2011

This paper presents a simple method for designing a robust controller that can be used on non-linear systems, here the air path of a downsized engine. This computationally inexpensive controller is thus obtained faster and more systematically than the usual look-up-table-based controllers. The successive steps of the method are: system identification, system normalization and linearization, nominal model design, model uncertainty design, and controller design with property verification. This robust controller is applied to the air path of a downsized spark ignition engine, i.e. intake manifold pressure control and boost pressure control.
Seeing a disaster as an opportunity – harnessing the energy of disaster survivors for change
Authors: Archer Diane , Boonyabancha Somsook
Published: June 2011

Disasters have tragic consequences, and people with the least resources at hand to rebuild their lives are often the worst affected. The traditional response to disasters is to provide immediate relief, without considering how the process of rebuilding lives and communities can be a positive opportunity for change. This opportunity can be facilitated in two ways: first, by having a clear understanding of how disaster survivors are not victims but agents for change; and second, by providing the tools and techniques to facilitate the change process. Case studies from Asia demonstrate how disaster-affected communities have rebuilt not only their homes but also their livelihoods, and have been empowered as a result.
Postgraduate Transnational Education in Nonbusiness Subjects: Can it Fit Conceptualizations of Curriculum Internationalization?
Authors: Chan Benjamin Tak-Yuen
Published: June 2011

The issue of teaching and learning in transnational education has increasingly received attention through studies about “curriculum internationalization.” To date, many of the examples and theorizations about curriculum internationalization are provided by business courses. This is largely a function of trade and commercial activities being inherently amenable to globalization forces, and hence facilitating the business subjects to adopt an international focus in curriculum planning and design. This article argues that curriculum internationalization also has significance for postgraduate science and social science programs delivered across borders, citing pharmacy and education as examples. However, the objectives of curriculum internationalization in these two are not narrowly focused on the functionalist notion of employability and performance as is found for business programs. Rather, they are considered to contribute toward the convergence of professionalization process of pharmacists worldwide for a postgraduate clinical pharmacy program, and the extension of a community of researchers to novice student researchers located overseas in the case of a professional doctorate in education. This difference in objectives calls for the construction of a more robust model of curriculum internationalization to guide international educators in their practice.
The Nurse’s Medication Day
Authors: Jennings Bonnie Mowinski , Sandelowski Margarete , Mark Barbara
Published: June 2011

The medication administration stage of the medication-use process is especially vulnerable to error because errors are least likely to be caught before reaching the patient. Medication administration, however, remains poorly understood. In this article we describe medication administration as observed in an ethnographic study conducted on one medical unit and one surgical unit. A central finding was that medication administration entailed a complex mixture of varied and often competing demands that temporally structured the nurses’ entire workday. Articulation work was evident in time management strategies nurses used to handle demands from institutional policies, technical devices, patients, the physical environment, and the medications themselves. The average number of doses of medication per patient was more than double the number policy groups have indicated. Medication administration is not simply the giving of drugs, nor does it have clearly defined temporal boundaries. Because of its inseparability from other nurses’ work, medication administration inherently entails interruption, thereby calling into question the current emphasis on reducing interruptions as a tactic to decrease medication errors.
Factors affecting e-book reader awareness, interest, and intention to use
Authors: Jung Jaemin , Chan-Olmsted Sylvia , Park Bellnine , Kim Youngju
Published: June 2011

This study attempts to identify the predictors of e-book reader diffusion with regard to consumer awareness, interest, and intention to use. Specifically, it assesses the relative influence of demographics, media usage/ownership, and personal traits/perception variables in the technology-adoption process. A national consumer survey conducted in South Korea, a leading country in the proliferation of e-book use, found that e-book reader awareness, interest, and adoption intention correlated positively with age, education, income, perceived need for print media, digital media ownership, personal innovativeness, and the perceived attributes of e-book readers. Regarding the relative effects of variable blocks, the most influential factors in predicting e-book reader awareness, e-book reader interest, and intention to use were demographics, personal innovativeness, and the perceived attributes of e-book readers, respectively.
Effects of different cetane number enhancement strategies on HCCI combustion and emissions
Authors: Hosseini V , Neill W S , Guo H , Chippior W L , Fairbridge C , Mitchell K
Published: June 2011

Cetane number is the accepted indicator for quantifying the autoignition characteristics of diesel fuels in compression ignition engines. Diesel fuel specifications typically require a minimum cetane number to achieve satisfactory combustion behaviour in conventional diesel engines. In contrast, a high cetane number fuel may not be beneficial for implementing high efficiency, clean combustion strategies such as homogeneous charge compression ignition (HCCI). The purpose of this study was to investigate cetane number effects on HCCI combustion and emissions. The experiments were conducted in a single-cylinder, variable compression ratio, cooperative fuel research engine operated in HCCI combustion mode. The fuels were finely atomized and partially vaporized in the intake manifold. The base fuel was a low cetane refining stream derived from oil sands sources. Three different methods were employed to increase the base fuel cetane number, namely hydroprocessing, cetane improver addition, and blending with a renewable fuel component. Results show that the three methods of cetane number enhancement produce significantly different HCCI combustion behaviour. The hydroprocessed fuels exhibited more stable and complete combustion than the base fuel, which resulted in a wider operating region, reduced carbon monoxide, unburned hydrocarbon, and nitrogen oxide (NO x) emissions, and lower indicated specific fuel consumption (ISFC). The main disadvantages of the hydroprocessed fuels were the higher exhaust gas recirculation rates required to retard the combustion phasing, which limits the maximum indicated mean effective pressure for a given intake pressure, and increased knock intensity due to a faster combustion process. In comparison, the other two methods of fuel cetane enhancement increased ISFC compared to the base fuel. The addition of nitrate cetane improver resulted in higher NO x emissions, while blending with a renewable fuel component increased hydrocarbon emissions. The experimental data provide evidence that the magnitude and phasing of low temperature heat release, as well as fuel volatility, play important roles in HCCI combustion.
Numerical modelling of diesel spray auto-ignition and combustion
Authors: Dhuchakallaya I , Watkins A P
Published: June 2011

This work presents the development and implementation of a spray combustion model based on the spray size distribution moments approach to spray modelling. The governing equations for both the gas and liquid phases are solved by the finite volume method based on an Eulerian framework. The model used in the auto-ignition and combustion analysis is a combination of the probability density function and eddy break-up approaches. This scheme is developed in order to effectively validate both ignition and combustion phases. It is designed to compromise between the chemical reaction rate when dealing with the auto-ignition mode, and the turbulence reaction rate which dominates the combustion mode using a reaction progress variable which represents the reaction level. These average reaction rate source terms in transport equations for species are evaluated by a probability density function averaging approach. The developed ignition and combustion model is shown to have significant potential as a numerical tool for predicting the phenomena involved in spray combustion in diesel engines.
Prediction of soot particle size distribution for turbulent reacting flow in a diesel engine
Authors: Lee J , Sung N W , Huh K Y
Published: June 2011

There is increasing interest in obtaining the size distribution as well as the number density and mass fraction of soot particles created by diesel engines. This study addresses this problem and particle size distributions are computed and validated in typical operating conditions of a diesel engine. The program KIVA is modified and integrated with CHEMKIN in order to be able to consider detailed gas phase kinetics and soot precursors using the conditional moment closure (CMC) model for turbulence/chemistry coupling. The soot simulator, SWEEP is then used to calculate the size distribution as a post-processing step at any given mixture fraction. The conditional results obtained at a mixture fraction of 0.12 are generally consistent with measurements over a range of engine operating conditions. However, the effect of differential diffusion in the probability density function weighted quantities affects the quality of the results obtained as a function of engine speed.