bluuebunny/crossref_metadata_2025 huggingface dataset:
Chromatin remodelling and chromosome damage distribution
Authors: Martínez-López W , Di Tomaso M V
Published: August 2006

Histone acetylation/deacetylation constitute the most relevant chromatin remodelling mechanism to control DNA access to nuclear machinery as well as to mutagenic agents. Thus, these epigenetics mechanisms could be involved in processing DNA lesions into chromosomal aberrations. Although radiation-induced DNA lesions are believed to occur randomly, in most cases chromosome breakpoints appear distributed in a non-random manner. In order to study the distribution of chromosome damage induced by clastogenic agents in relation to chromosome histone acetylation patterns, an experimental model based on treating Chinese hamster cells with endonucleases and ionizing radiations as well as immunolabelling metaphase chromosomes with antibodies to acetylated histone H4 was developed. The analysis of intra- and interchromosome breakpoint distribution has been carried out on G-banded chromosomes, and results obtained were correlated with chromosome acetylated histone H4 profiles. A co-localization of intrachromosomal breakpoints induced by AluI, BamHI and DNase I as well as by neutrons and g-rays was observed. Radiation- and endonuclease-induced breakpoints tend to cluster in less condensed chromosome regions (G-light bands) that show the highest levels of acetylated histone H4. The analysis of interchromosomal distribution of radiation-induced lesions showed a concentration of breakpoints in Chinese hamster chromosomes with particular histone acetylation patterns. The fact that chromosome breakpoints occur more frequently in transcriptionally competent chromosome regions suggests that chromatin conformation and nuclear architecture could play a role in the distribution of chromosome lesions.
Dietary di(2-ethylhexyl)phthalate-impaired glucose metabolism in experimental animals
Authors: Martinelli Marcela I , Mocchiutti Norberto O , Bernal Claudio A
Published: August 2006

The effects of chronic intake of di(2-ethylhexyl)phthalate (DEHP) on the main intermediate glycolytic metabolites in liver and gastrocnemius muscle were investigated in experimental animals. Male Wistar rats (90 -100 g) were fed for 21 days either with a standard chow or the same diet supplemented with 2% (w/w) of DEHP. The DEHP-fed rats had an altered in vivo glucose tolerance associated with abnormal glucose intermediate metabolite contents in liver and skeletal muscle. In these rats, the hepatic content of glucose-6 -phosphate (G-6 -P), fructose-6 -phosphate, pyruvate, lactate, glucose-1 -phosphate and glycogen decreased. At the same time, the G-6 -P content decreased while the pyruvate and lactate levels increased in skeletal muscle. These data, along with the high plasma glucose concentration and the normal lactate blood levels of this group, could indicate that DEHP-fed rats could present a deficiency in muscle glucose and lactate transport, a reduction of the flux through muscle hexokinase and hepatic glucokinase, and a reduction in glycogen synthesis.
Effect of gallic acid on renal biochemical alterations in male Wistar rats induced by ferric nitriloacetic acid
Authors: Prasad Lakshmi , Khan Tajdar Husain , Jahangir Tamanna , Sultana Sarwat
Published: August 2006

The present study is an effort to identify a potent chemopreventive agent against various diseases (including cancer) in which oxidative stress and cell proliferation plays an important causative role. This study was designed to investigate the effect of gallic acid against ferric nitrilotriacetic acid (Fe-NTA)-induced carcinogen/drug metabolizing phase I and phase II enzymes, anti-oxidative parameters, kidney markers, tumour promotion markers and lipid peroxidation (LPO) in kidney of male Wistar rats. Fe-NTA (9 mg Fe/kg body weight, intraperitoneally) caused significant depletion in the detoxification and antioxidant enzyme armoury with concomitant elevation in renal LPO, serum creatinine, blood urea nitrogen, hydrogen peroxide generation, ornithine decarboxylase activity and [3H]thymidine incorporation into renal DNA. However, pretreatment of animals with gallic acid (10 and 20 mg/kg body weight) resulted in a significant decrease in the levels of the parameters measured (P < 0.001). Renal glutathione content (P < 0.001), glutathione metabolizing enzyme (P < 0.001) and antioxidant enzyme levels were also recovered to a significant level (P < 0.001). The enhanced reduced glutathione level and enzyme activities involved in xenobiotic metabolism and maintaining antioxidant status of cells are suggestive of a chemopreventive efficacy of gallic acid against Fe-NTA-mediated oxidative stress, toxicity and cell proliferative response in Wistar rats.
Delta-aminolevulinic acid dehydratase inhibition and oxidative stress in relation to blood lead among urban adolescents
Authors: Ahamed M , Verma S , Kumar A , Siddiqui M KJ
Published: August 2006

To explore lead-induced oxidative stress among urban adolescents, the present study, the first from India, was designed to determine the proportion of urban adolescents with blood lead > 10 μg/dL and its impact on selected oxidative stress parameters and delta-aminolevulinic acid dehydratase (δ-ALAD) inhibition, which could be used as biomarkers of lead intoxication. A total of 39, urban, male adolescents, drawn from Lucknow and adjoining areas, were recruited to determine lead, d-ALAD, malondialdehyde (MDA) and glutathione (GSH) in blood and catalase (CAT) in RBCs. Mean level of blood lead was 9.96 ± 3.63 μg/dL (4.62 - 18.64); 43% of adolescents crossed the Centre for Disease Control (CDC) intervention level of 10 mg/dL blood lead. On the basis of blood lead levels (BLLs), adolescents were categorized into two groups: Group I and Group II had a blood lead < 10 μg/dL (7.40 ± 1.62) and < 10 μg/dL (13.27 ± 2.67), respectively, with significantly different mean values (P < 0.001). Age, sex, body mass index (BMI), Hb level (malnutrition), and area of living as confounders of lead exposure and toxicity were not statistically different between the two groups. However, d-ALAD activity was significantly lower (P < 0.001), while CAT activity was higher in Group II than in Group I (P < 0.01). MDA level was also significantly higher in Group II compared to Group I (P < 0.001). There were significant negative correlation of BLL with d-ALAD (r = -0.592, P < 0.001), and positive correlations with CAT (r= -0.485, P < 0.01) and MDA (r = -0.717, P < 0.001). Interestingly, d-ALAD, in turn, had significant negative correlations with CAT (r = -0.456, P <0.01) and MDA (r = -0.507, P < 0.01). Results of the present pilot study provide clues to the possible low level of lead-induced oxidative stress in urban adolescents, suggesting that lead-induced d-ALAD inhibition can also be an indicator of oxidative stress. The potential of oxidative stress parameters to be used as biomarkers of lead toxicity warranted further investigation.
Moral Deliberation in Psychiatric Nursing Practice
Authors: Abma Tineke A , Widdershoven Guy AM
Published: August 2006

Moral deliberation has been receiving more attention in nursing ethics. Several ethical conversation models have been developed. This article explores the feasibility of the so-called CARE (Considerations, Actions, Reasons, Experiences) model as a framework for moral deliberation in psychiatric nursing practice. This model was used in combination with narrative and dialogical approaches to foster discourse between various stakeholders about coercion in a closed admission clinic in a mental hospital in the Netherlands. The findings demonstrate that the CARE model provides a substantial framework for structuring moral deliberations. Narratives and dialogue are useful tools for broadening issues in conversations, to engage various stakeholders (including patients), and to gain shared understandings.
Nurses' Fears and Professional Obligations Concerning Possible Human-to-Human Avian Flu
Authors: Tzeng Huey-Ming , Yin Chang-Yi
Published: August 2006

This survey aimed to illustrate factors that contribute to nurses' fear when faced with a possible human-to-human avian flu pandemic and their willingness to care for patients with avian flu in Taiwan. The participants were nursing students with a lesser nursing credential who were currently enrolled in a bachelor degree program in a private university in southern Taiwan. Nearly 42% of the nurses did not think that, if there were an outbreak of avian flu, their working hospitals would have sufficient infection control measures and equipment to prevent nosocomial infection in their working environment. About 57% of the nurse participants indicated that they were willing to care for patients infected with avian influenza. Nurses' fear about an unknown infectious disease, such as the H5N1 influenza virus, could easily be heightened to levels above those occurring during the 2003 severe acute respiratory syndrome outbreak in Taiwan.
Opportunities and Obstacles for Good Work in Nursing
Authors: Miller Joan F
Published: August 2006

Good work in nursing is work that is scientifically effective as well as morally and socially responsible. The purpose of this study was to examine variables that sustain good work among entering nurses (with one to five years of experience) and experienced professional nurses despite the obstacles they encounter. In addition to role models and mentors, entering and experienced nurses identified team work, cohesiveness and shared values as levers for good work. These nurses used prioritization, team building and contemplative practices to overcome obstacles. Entering professional nurses tended to avoid conflict in the work setting. Experienced nurses reported forming teams of decision makers who share similar values to resolve conflict. These findings have implications for nurse education and nursing practice. Reflection on the importance of values and virtue in sustaining good work is important. Entering professional nurses should be encouraged to seek positive role models and reflect on the lessons that can be learned from experienced exemplary nurses.
An Iranian Perspective on Patients' Rights
Authors: Joolaee Soodabeh , Nikbakht-Nasrabadi Alireza , Parsa-Yekta Zohreh , Tschudin Verena , Mansouri Iman
Published: August 2006

The aim of this phenomenological research study carried out in Iran was to capture the meaning of patients' rights from the lived experiences of patients and their companions. To achieve this, 12 semistructured interviews were conducted during 2005 in a teaching hospital in Tehran with patients and/or their companions. In addition, extensive field notes were compiled during the interviews. The data were analyzed using Benner's thematic analysis. The themes captured were classified into three main categories, with certain themes identified within each category. The categories were: (1) the concept of patients' rights; (2) barriers to patients' rights; and (3) facilitators of patients' rights. The distinctive themes within each of the categories were identified as: (1a) receiving real care, (1b) focus on the patient, and (1c) equality and accessibility; (2a) dissatisfaction with caregivers, and (2b) specific work environment limitations; (3a) the patient's companion, (3b) a responsible system, and (3c) the public's awareness of rights. Although certain themes identified closely resemble those identified in international patients' bills of rights, the current study focused on themes that are particularly relevant to the Iranian sociocultural context.
Belgian Nurses' Views on Codes of Ethics: Development, Dissemination, Implementation
Authors: Verpeet Ellen , de Casterlé Bernadette Dierckx , Lemiengre Joke , Gastmans Chris
Published: August 2006

The aim of this study was to explore how Belgian nurses view issues related to the development, dissemination and implementation of a code of ethics for nurses. Fifty nurses took part in eight focus groups. The participants stated that, on the whole, a code of ethics for nurses would be useful. They stressed that a code should be a practical and useful instrument developed by nurses for nurses, and that it should be formulated and presented in a practical way, just as educational courses dealing specifically with codes of ethics require a practical approach to be effective. They emphasized that the development of a code should be an ongoing process, enabling nurses to provide input as they reflect on the ethical issues dealt with in the code and apply the code in their practice. Finally, they stressed the need for support at institutional level for the effective implementation of a code.
Conditions for Patient Participation and Non-Participation in Health Care
Authors: Eldh Ann Catrine , Ekman Inger , Ehnfors Margareta
Published: August 2006

This study explored patients' experiences of participation and non-participation in their health care. A questionnaire-based survey method was used. Content analysis showed that conditions for patient participation occurred when information was provided not by using standard procedures but based on individual needs and accompanied by explanations, when the patient was regarded as an individual, when the patient's knowledge was recognized by staff, and when the patient made decisions based on knowledge and needs, or performed self-care. Thus, to provide conditions for true patient participation, professionals need to recognize each patient's unique knowledge and respect the individual's description of his or her situation rather than just inviting the person to participate in decision making.
Understanding Privacy in Occupational Health Services
Authors: Heikkinen Anne , Wickström Gustav , Leino-Kilpi Helena
Published: August 2006

The aim of this study was to gain a deeper understanding of privacy in occupational health services. Data were collected through in-depth theme interviews with occupational health professionals (n=15), employees (n=15) and employers (n=14). Our findings indicate that privacy, in this context, is a complex and multilayered concept, and that companies as well as individual employees have their own core secrets. Co-operation between the three groups proved challenging: occupational health professionals have to consider carefully in which situations and how much they are entitled to release private information on individual employees for the benefit of the whole company. Privacy is thus not an absolute right of an individual, but involves the idea of sharing responsibility. The findings open up useful new perspectives on ethical questions of privacy and on the development of occupational health practices.
Zones of indistinction: bio-political contestations in the urban arena
Authors: Gandy Matthew
Published: August 2006

This essay explores the idea of ‘bio-politics’ in relation to the modern city. The concept is traced through its original Foucauldian formulation to more recent explorations of the relationship between the body and the city. We explore the idea through the emergence of discourses on hygiene, public health and differing conceptions of ‘urban order’. We find that the bio-political dynamics of urban space encompass both juridical and dispersed sources of power in modern societies. It is concluded that existing conceptions of power in urban space need to take account of those diffuse sources of power that enable the modern city to function in spite of its contradictory dynamics. We also need to contend with those ‘zones of indistinction’ which appear to lie outside conventional urban discourse yet reveal much about the hidden dimensions of urban modernity.
The vital city: public analysis, dairies and slaughterhouses in nineteenth-century Britain
Authors: Otter Chris
Published: August 2006

Despite the premises of classical political economy, which urged limited intervention in the production and circulation of vital commodities, nineteenth-century British government became heavily involved in the urban food supply. This paper explores three areas where such governmental intervention was evident: the constitution of a network of public analysts devoted to the chemical sampling of foodstuffs, the increasing regulation of the dairy industry, and the construction of public abattoirs. Although these regulatory systems suggest an active, interventionary form of government, they can still be seen as broadly liberal in nature: they usually involved a substantial degree of delegation, pragmatism and negotiation, and their implementation was slow and geographically patchy. Nonetheless, substantial changes in urban nutritional practices can be discerned by 1900. By this time, little food was produced within British cities: much came from remote parts of Britain or overseas, and the supply was far more technologically-mediated than in earlier centuries. In the milk and meat trades, we can see the first moves towards industrialisation. Securing the vitality of the city, therefore, had entailed the development of distinct regulatory strategies and the emergence of new nutritional geographies, both of which would significantly shape the dietary history of the twentieth century.
Kitchen sink dramas: women, modernity and space in Weimar Germany
Authors: Jerram Leif
Published: August 2006

This article uses historical evidence about the competing designs of kitchens in 1920s German social housing to argue that historians (and, to an extent, geographers) have overlooked the coercive capacity of space to compel certain forms of social relationship. Such has been the potency of the ‘cultural’ model in history and geography that the ‘material’ world has been cloaked by language and symbol. Bourgeois politicians, planners and reformers in 1920s Germany were not only compelled to think about domestic space for the poor for the first time, but had to actually produce the physical space if they wanted to make their ideologies ‘live’. This article also shows that if we disaggregate the space of the home into its constituent parts (rather than simply contrasting the private and the public realms), different gender ideologies could be designed into domestic space, forcing families to adopt ways of living and patterns of sociability according to the priorities of, variously, ‘Americanizers’, socialists, conservatives and liberals. The kitchen designs of Frankfurt are well known, but in fact those of Munich were probably more widespread, and so this work further serves to decentre the canon of Modernism which dominates much discussion of Weimar building.
Urban design and civic spaces: nature at the Parc des Buttes-Chaumont in Paris
Authors: Strohmayer Ulf
Published: August 2006

Transcending the dualism between ‘nature’ and ‘culture’ has been one of the central aims of geographical knowledge during the last decade or so. The present paper adds to this growing body of literature by focusing on the construction of a key space of the French Second Empire (1852-1870), the Parc des Buttes-Chaumont in the newly created 19th arrondissement in Paris. The paper argues that the nexus between culture and nature-what has been described most fittingly as ‘social nature’ in the literature-can profitably be approached through the lenses afforded by a reformulated concept of labour. Taking cues from Don Mitchell’s conceptual notion of ‘dead labour’, the paper explores the impact of both technology and design on an emerging urban nature that was to be centrally implicated in the naturalization of many values within an emerging bourgeois, Western world with its emphasis on the commodification of increasing parts of everyday life. Ostensibly non-commodified urban park landscapes were implicated in this process precisely because they embodied a notion of ‘labour’ that was-and continues to be-both necessary and homogeneous and thus akin to the sense of labour developing in the world of commerce at the same time.
Germs, genes and postcolonial geographies: reading the return of tuberculosis to Leicester, UK, 2001
Authors: Bell Morag , Brown Tim , Faire Lucy
Published: August 2006

This paper is inspired by an outbreak of pulmonary tuberculosis in the British East Midlands city of Leicester in 2001. In an era characterized by unprecedented advances in Western medical science an event of this kind might appear surprising. It challenges the feeling of wellbeing held in many Western countries, particularly in relation to diseases that appear both temporally and spatially distant. The paper examines how the event was reported in regional and national newspaper media and considers the significance attached to scale in the interactions between experts, the media and the public. In our analysis we mobilize a particular reading based on two biological metaphors, the membrane and the gene. We use this reading to reconsider the connectivity between disease, nation and identity in a world that is increasingly fluid, mobile, anxious and uncertain.
Materialist returns: practising cultural geography in and for a more-than-human world
Authors: Whatmore Sarah
Published: August 2006

This paper surveys the return to materialist concerns in the work of a new generation of cultural geographers informed by their engagements with science and technology studies and performance studies, on the one hand, and by their worldly involvements in the politically charged climate of relations between science and society on the other. It argues that these efforts centre on new ways of approaching the vital nexus between the bio (life) and the geo (earth), or the ‘livingness’ of the world, in a context in which the modality of life is politically and technologically molten. It identifies some of the major innovations in theory, style and application associated with this work and some of the key challenges that it poses for the practice of cultural geography.

Thinking is neither a line drawn between subject and object nor a revolving of one around the other. Rather thinking takes place in the relationship of territory and earth... involving a gradual but thorough displacement from text to territory.1
A Shock Factor Based Approach for the Damage Assessment of Plane Plates Subjected to Underwater Explosion
Authors: Rajendran R , Narasimhan K
Published: August 2006

The energy of an underwater shock wave primarily depends on the charge quantity and the stand-off. The shock factor, which is an indicator of the shock energy, is important in that the kick of velocity developed by a plate is dependent upon it. This investigation introduces the term ‘effective shock factor’, which is the shock factor to the power of 1.03 multiplied by the square root of the coupling factor, to establish the relationship between it and the elastic and yield response of plane plates of circular and rectangular geometries. Experiments were carried out on a high-strength steel plate of 300 mm × 250 mm × 8 mm for comparison. Published results on circular and rectangular plates are compared with the prediction.
Gross Plastic Deformation of Axisymmetric Pressure Vessel Heads
Authors: Camilleri D , Hamilton R , Mackenzie D
Published: August 2006

The gross plastic deformation and associated plastic loads of four axisymmetric torispherical pressure vessels are determined by two criteria of plastic collapse: the ASME twice elastic slope (TES) criterion and the recently proposed plastic work curvature (PWC) criterion. Finite element analysis was performed assuming small and large deformation theory and elastic-perfectly plastic and bilinear kinematic hardening material models. Two plastic collapse modes are identified: bending-dominated plastic collapse of the knuckle region in small deformation models and membrane-dominated plastic collapse of the cylinder or domed end in large deformation models. In both circumstances, the PWC criterion indicates that a plastic hinge bending mechanism leads to gross plastic deformation and is used as a parameter to identify the respective plastic loads. The results of the analyses also show that the PWC criterion leads to higher design loads for strain hardening structures than the TES criterion, as it takes account of the effect of strain hardening on the evolution of the gross plastic deformation mechanism.
An Experimental and Computational Study of the Crushing of Metallic Hemispherical Shells Between Two Rigid Flat Platens
Authors: Gupta P. K , Gupta N. K
Published: August 2006

The axial compression of aluminium spherical shells with a ratio of mean radius to wall thickness ranging from 15 to 50 was carried out between two rigid flat parallel platens. Quasi-static tests were conducted on an Instron machine (model 1197) of 50 t capacity. Spherical shells of different radius and thickness were tested in order to identify their collapse modes and to study the associated energy absorption capacity. In experiments, all shells were found to collapse owing to the formation of inward dimpling associated with a rolling plastic hinge. The deformation of the shells was also studied and analysed with the help of the finite element code FORGE2. Predicted variations in different components of strain and stress are presented. Experimental and computed results are compared. Some of the obtained results are also compared with the solutions proposed in earlier studies. On the basis of the findings of the experiments and computational model, the basic mechanism of deformation of shells is presented and discussed.
Application of Bragg Grating Sensors in Dental Biomechanics
Authors: Carvalho L , Silva J. C. C , Nogueira R. N , Pinto J. L , Kalinowski H. J , Simúes J. A
Published: August 2006

This paper describes the use of fibre Bragg grating (FBG) sensors to measure strains at a mandible surface that are caused by static or impact loads on a dental implant. The measuring apparatus uses a fixed optical filter reference scheme and is able to detect dynamic signals with frequency components of up to 10 kHz. A dried implanted cadaveric mandible was used with strain gauges and FBG sensors placed at the outer surface in the direction of the longitudinal axis of the implant. The implants were loaded statically and dynamically and uniaxial strains recorded. The study demonstrates the ability of the FBG as a biomechanical sensor.
A Parameter Identifying a Kalman Filter Observer for Vehicle Handling Dynamics
Authors: Hodgson G , Best M C
Published: August 2006

The paper presents a method for designing a non-linear (i.e. extended) Kalman filter that is also parameter adaptive and hence capable of online identification of its model. The filter model is deliberately simple in structure and low order, yet includes non-linear, load-varying tyre force calculations to ensure accuracy over a range of test conditions. Shape parameters within the (Pacejka) tyre model are adapted rapidly in real time, to maintain excellent state reconstruction accuracy, and provide valuable real-time lateral and vertical tyre force information. The filter is tested in both simulated and test vehicle environments and provides good results. The paper also provides an illustration of the importance of good Kalman filter design practice in terms of selection and tuning of the noise matrices, particularly in terms of the influence of model/sensor error cross-correlations.
Determination of the Crush Stiffness Coefficients of a Typical Aftermarket Frontal Protective Guard Used in Light Trucks and Vans with Comparisons between Guard Stiffness and Frontal Vehicle Crush Coefficients
Authors: McCoy M L , Lankarani H M
Published: August 2006

Crush stiffness coefficients were determined for a typical I-beam constructed frontal grill guard used in the aftermarket on vehicles classified as light trucks or vans. These crush coefficients were determined by virtual impacts of a typical guard construction into a rigid barrier using finite element analysis (FEA) methods and collision stiffness computations. It was found that the addition of a frontal protection guard is capable of significantly changing the frontal stiffness of the vehicle to which it is attached. The federal motor vehicle safety standards (FMVSSs) require vehicles to give a certain crash response in order to protect occupants. Engineers have designed features such as frontal and rear crash zones to dissipate crash energies to meet the FMVSS requirements. Changing the stiffness of the vehicle by the addition of a frontal guard may alter the crash response and airbag deployment of the vehicle to which it is attached, along with the crash response of the guard-struck vehicle. The determination of the crush stiffness coefficients for a frontal guard will allow a comparison with the engineered frontal stiffness of vehicles in order to start the examination of the effect of frontal guard stiffness on crashworthiness of the collision partners. In addition, the determination of these coefficients will allow accident reconstructionists to assess the change in velocity of vehicles involved in collisions with frontal guards from guard crush damage.
Dent Resistance of Aluminium and Magnesium Alloys
Authors: Peixinho N , Pinho A C M
Published: August 2006

This study presents results concerning the stiffness and denting resistance of 6111-T4 aluminium alloy and AZ31B-H24 magnesium alloy. Experimental results of dynamic denting are compared with numerical simulations performed using LS-DYNA software. The experimental tests were performed on 0.9 and 1.09 mm thick plates clamped in a circular area with a diameter of 80 mm. Dynamic denting was accomplished by dropping different indenters from heights ranging from 0.36 to 1.7 m. The obtained experimental results enabled the properties of the two light alloys tested to be compared. The results of the numerical simulations display a good correlation with experiments if dynamic effects are introduced into the constitutive equation of the material through the Cowper-Symonds coefficients.
Anti-Lock Braking Control of a Hybrid Brake-By-Wire System
Authors: Anwar S
Published: August 2006

This paper presents a non-linear sliding mode type controller for slip regulation in a braking event for a hybrid electromagnetic-electrohydraulic brake-by-wire (BBW) system. The anti-lock braking system (ABS) controller modifies the brake torque command generated by a supervisory controller based on a driver request via the brake pedal sensor. The brake torque command is then generated by a closed-loop actuator control algorithm to control the eddy current brake (ECB) and electrohydraulic brake (EHB) systems. The proposed control algorithm shows very good slip regulation in a braking event on low friction coefficient surfaces when compared with non-ABS braking. It has been observed that the eddy current brake provided most of the torque while the electrohydraulic brake compensated for the difference between ABS torque command and estimated ECB torque. The result is a very smooth ABS stop minimizing the noise, vibration, and harshness (NVH) of current hydraulic ABS systems. It is also shown that the closed-loop system is stable in the sense of Lyapunov stability theory.
Turbo-Cool Turbocharging System for Spark Ignition Engines
Authors: Wang Lin-Shu , Yang Shiyou
Published: August 2006

The problem of matching a turbocharging system to a piston engine is investigated. The variable-geometry turbine (VGT) turbocharger used for spark ignition (SI) engine application is studied in some detail. A critical factor that has been overlooked in considering VGT turbochargers for SI engine application in the past is the backpressure to the piston engine and, consequently, the resulting residual gas and its effect on the temperature of the in-cylinder mixture at the beginning of combustion. That is, VGT turbocharger operation affects engine backpressure, which affects the in-cylinder mixture temperature, which affects the tendency for engine knock, which limits engine performance. The higher backpressure also raises the turbine entry temperature. A new turbocharging system named Turbo-Cool is proposed in this paper. The Turbo-Cool turbocharging system utilizes more complete exhaust gas expansion in the turbine to achieve a higher engine effective expansion ratio (EER) in a straightforward manner. The novelty of the concept is that the excess power from higher exhaust gas expansion through the turbine (rather than being considered as an object for power recovery, as in the classical turbocompound concept) is used for conditioning intake charge air for the purpose of engine loss reduction. The validation of the proposed concept is carried out using a commercial engine simulation code. The simulation results show that the Turbo-Cool turbocharging system and the VGT turbocharger are indispensable to each other in producing engine performance of superior brake mean effective pressure (b.m.e.p.) and excellent torque back-up, as well as improved engine efficiency. It is argued that the Turbo-Cool turbocharging system is a basic design that might bring about the full potential benefits of turbocharging for SI engines.
Eco-Diesel Engine Fuelled with Rapeseed Oil Methyl Ester and Ethanol. Part 2: Comparison of Emissions and Efficiency for Two Base Fuels: Diesel Fuel and Ester
Authors: Kowalewicz A
Published: August 2006

A comparison has been made of the efficiency and emissions from a single-cylinder naturally aspirated direct injection compression ignition engine when fuelled either with diesel fuel (DF) or rapeseed oil methyl ester (RME) and additionally with ethanol in different proportions injected into the inlet port during the suction stroke. Investigations were performed at two constant loads, high and low. At each load the proportions of ethanol and base fuel were changed in such a way that the load was held constant. At each load the engine operated at a constant speed and for three injection timings. The obtained results were similar for both fuels, but in the case of RME there were lower carbon dioxide and smoke emissions and in some operating conditions NO x emission was observed. The aim of the ethanol injection, which was produced with air premixed with a homogeneous mixture in the cylinder, was to promote and accelerate combustion of DF/RME droplets, resulting in shorter combustion of the total fuel. The second objective of ethanol addition was to decrease the emissions of smoke and carbon dioxide, because as ethanol burns its combustion products have more H2 O and less CO2. The aim was to provide a sufficient effective energetic fraction of ethanol in order to reach a satisfactory decrease in emissions, which was found to be about 25 per cent for RME and about 20 per cent for diesel fuel.
A Cat-and-Mouse Type Rotary Engine: Engine Design and Performance Evaluation
Authors: Sakita Masami
Published: August 2006

This paper describes the overall design of a cat-and-mouse type rotary engine, and its performance evaluation. The rotary engine is equipped with a toroidal or quasi-toroidal working chamber, in which two sets of piston assemblies rotate around the piston shaft at different speeds. While one piston assembly decelerates, the other accelerates. These actions allow the piston assembly pair to increase or decrease the subchamber volumes. As part of this work, two computer models were developed, one for the proposed rotary engine and the other for a conventional reciprocating engine, and the performance of the rotary engine was compared against that of the reciprocating engine. The analysis results using the computer models indicate that the proposed rotary engine should be able to generate substantially higher bmep than the engines available in the market if the proposed engine is able to operate as intended.
Application of Synchronization and Continuous Control to a Chaotic Automotive Wiper System
Authors: Chang Shun-Chang
Published: August 2006

This study investigates the complex dynamic behaviour of an automotive wiper system by determining time responses, Poincaré maps and frequency spectra. The largest Lyapunov exponent is estimated from the synchronization properties to identify periodic and chaotic motions. Finally, the synchronization and the continuous control are applied to control chaotic motions. Accordingly, this study considers the non-linear dynamics and chaotic control of an automotive wiper system, which consists of two blades driven by a DC motor via the two connected four-bar linkages. Some simulation results are presented to confirm the feasibility of the proposed method.
Oxygen-Enriched Combustion of the First Cycle During Cold Start in a Liquefied Petroleum Gas Spark-Ignition Engine
Authors: Li Gong , Li Liguang , Qiao Xinqi , Xiao Guangfei , Qiu Dongping
Published: August 2006

The first firing cycle is very important for cold-start. Misfire of the first firing cycle can lead to significant hydrocarbon (HC) emissions and affect the subsequent cycles. Research has proved that the oxygen-enriched intake air (OEA) method is a useful technique to reduce cold-phase HC and carbon monoxide (CO) emissions from automotive gasoline engines. However, few researchers have studied oxygen-enriched combustion characteristics based on the first firing cycle analysis during cold-start. The present paper presents a comparison of atmospheric air with OEA in the combustion of the first cycle during cold-start in a liquefied petroleum gas spark-ignition engine. Cylinder pressure, engine speed, HC, CO, and nitric oxide (NO) emissions were collected. The heat release rate of atmospheric air and OEA combustion are calculated. Test results show that atmospheric air and OEA have similar high transients in HC emissions at cold-start. However, OEA reduces CO emissions and increases NO emissions. Comparing the heat release rate curves, oxygen-enriched combustion can lead to heat release earlier and higher than normal air combustion.
In-Cylinder Friction Reduction Using a Surface Finish Optimization Technique
Authors: Rahnejat H , Balakrishnan S , King P D , Howell-Smith S
Published: August 2006

The paper describes the importance of reducing frictional losses in internal combustion (IC) engines, thereby improving engine efficiency. One of the main sources contributing significantly to engine friction is the interaction between the piston compression and oil rings and the cylinder bore/liner. Improving the tribological performance in these conjunctions has the greatest potential for performance improvement in the IC engine. Traditionally, the approaches used to tackle this problem have relied heavily on empirical engineering judgement. These have resulted in many inconclusive studies, involving a large number of alternatives, including the introduction of cylinder liners with surface modification work and/or with special coatings. This paper highlights a fundamental investigation of surface modification and coating and its impact on frictional performance. The study combines numerical and experimental approaches. Very good agreement is found between the conclusions of numerical predictions and those of engine test bed work.
Constant Force Restraints for Frontal Collisions
Authors: Paulitz T J , Blackketter D M , Rink K K
Published: August 2006

This paper presents a model demonstrating the concept of a constant force restraint (CFR) system for frontal collisions. A three-bodied dynamic model of a 50th percentile anthropometric test dummy (ATD) in a 35 mile/h frontal collision was made using Lagrangian dynamics and verified with test data from the NHTSA. The model was used to compare visco-elastic and constant force seatbelt models in a 1998 Chevy Malibu. The viscoelastic seatbelt simulation was able to reproduce accurately the shape and magnitude of pelvis, chest, and head accelerations when compared to test data. The constant force seatbelt simulation showed reductions in pelvis, chest, and head accelerations by 56, 62, and 63 per cent respectively. The peak lap belt force was reduced by 60 per cent. Relative head rotation was reduced by 16°. A CFR system has the potential to reduce the risk of injury significantly by reducing forces and accelerations on the occupant. These results show great potential to reduce head injury criteria and could be applied to adaptive restraint systems by tuning the CFR to the occupant and crash.
Robust Design of an Automobile Front Bumper Using Design of Experiments
Authors: Lee Kwon-Hee , Bang Il-Kwon
Published: August 2006

Bumpers are structural components installed to reduce physical damage to the front and rear ends of a passenger motor vehicle from low-speed collisions. Damage and protection assessments are the commonly used design criteria in bumper design. For damage assessment, the relative displacements representing stiffness performance are defined and examined. At the protodesign stage for a new car, finite element (FE) analysis is often utilized to predict the stiffness of a bumper. However, conventional bumper analysis through FEM outputs a constant stiffness even though the stiffness has some distribution due to uncertainties. In this research, the uncertainties are assumed to be the tolerances of thicknesses. Under this uncertain condition, the displacements representing stiffness are calculated by approximate statistics and by worst-case analysis. Then, a robust design is determined by design of experiments (DOE) using the orthogonal array strategy to find the design having a minimum weight of bumper within the stiffness constraints. In this research, the thicknesses of the inner beam, outer beam, and stay are treated as design variables. The robust design procedure for a bumper, considering the uncertain thicknesses, is presented.
Liquid Spring Shock Absorber with Controllable Magnetorheological Damping
Authors: Hong S-R , Wang Gang , Hu Wei , Wereley N M
Published: August 2006

An automotive suspension strut is investigated that utilizes compressible magnetorheological (CMR) fluid. A CMR strut consists of a double-ended rod in a hydraulic cylinder and a bypass comprising tubing and an MR valve. The diameter of the rods on either side of the piston are set to be different in order to develop spring force by compressing the MR fluid hydrostatically as a result of varying shaft volume in the hydraulic cylinder. The MR bypass valve is adopted to develop a controllable damping force. A hydromechanical model of the CMR strut is derived by considering lumped hydraulic parameters such as compliances of chambers inside the cylinder and flow resistances through the MR bypass valve. The spring force and nominal spring rate owing to fluid compressibility and the controllable flow resistance and pressure drop in the bypass were analytically investigated on the basis of the model. Finally, a CMR strut, filled with silicone oil-based MR fluid, is fabricated and tested. The spring force and variable damping force of the CMR strut are clearly observed in the measured data, and compare favourably with the analytical model. Additionally, characteristics of a double-rod strut whose rod diameters are the same, so that the shaft volume in the hydraulic cylinder is constant, are analysed and compared with a CMR strut whose rod diameters are different.
An Automotive Engine Charge-Air Intake Conditioner System: Analysis of Fuel Economy Benefits in a Gasoline Engine Application
Authors: Taitt D W , Garner C P , Swain E , Blundell D , Pearson R J , Turner J W G
Published: August 2006

A combination of analytical techniques has been used to quantify the potential fuel economy benefits of an automotive engine charge-air intake conditioner system applied to a spark-ignited gasoline engine. This system employs a compressor, intercooler, and expander to provide increased charge density with the possibility of reducing charge-air temperature below sink temperature. This reduction in charge-air temperature provides the potential for improved knock resistance at full load; thereby allowing the possibility of increasing compression ratio with corresponding benefits in thermodynamic cycle efficiency and part-load fuel economy. The four linked and interfaced models comprised a first-law thermodynamic model of the charge-air conditioner system, a one-dimensional engine cycle simulation, a two-zone combustion model, and a knock criterion model. An analysis was carried out under full load at 3000 r/min and showed that a charge-air conditioner system - with compressor, intercooler, and expander efficiencies of 0.8 - allowed the compression ratio to be increased by approximately half a ratio, which gave up to 1.5 per cent reduction in brake specific fuel consumption at 2000 r/min 2 bar brake mean effective pressure when compared with a conventional pressure charger intercooler system with no expander.
Intraoperative Knee Anthropometrics: Correlation with Cartilage Wear
Authors: Rooney N , Fitzpatrick D P , Beverland D E
Published: August 2006

Accurate knee morphology is of value in determining the correct sizing of prosthetic implants. Intraoperative measurement of key linear dimensional variables was carried out on 196 Caucasian knees (osteoarthritic patients: 68 male and 128 female). Of the 196 knees measured, 70 had extensive cartilage degeneration. Statistical analysis was carried out on this large sample size of data. Summary statistics and correlation coefficients between variables were determined and compared between subgroups. Male knees were on average larger than female knees. Higher correlation was found between variables for males than between variables for females. Overall, the patellar dimensions were seen to correlate least well with other anatomical variables. High correlation between femoral variables supports current femoral sizing procedure, although routine patellar resection practices are called into question. Average values for the 70 knees with extensive cartilage degeneration were significantly smaller ( P < 0.01) than their counterparts for the other 126 knees. For a measurement not containing cartilage, such as femoral epicondylar width, this difference cannot be accounted for by the loss of cartilage owing to wear. This suggests that, for similar height and weight, a naturally narrower femoral epicondylar width may be associated with severe osteoarthritis.
Virtual Reality and a Haptic Master-Slave Set-Up in Post-Stroke Upper-Limb Rehabilitation
Authors: Houtsma J A , Van Houten F J A M
Published: August 2006

Since the number of stroke patients is ever growing, and since studies show that the patients can benefit from more exercise, the possible use of virtual reality and haptic devices in the rehabilitation of stroke patients is researched. Besides offering more independent and challenging exercise possibilities, the inherent registration capabilities of the haptic devices open up the possibility of monitoring patients' motions in an objective way. This research results in the implementation of a VR mock-up of an exercise in which patients use both hands and a stick to push away a ball, that is tossed at them. In this mock-up, two FCS HapticMasters are used in a master-slave set-up to mimic the behaviour of the stick. The implementation of the scene shows that there are currently limitations, in the hardware as well as in the software, that cause the virtual exercise to behave differently to the real-life exercise. Consequences for the therapeutic value are subject to further research.