bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of the Flushing Response in the Relationship Between Alcohol Consumption and Insulin Resistance
Authors: Jung Jin‐Gyu , Kim Jong‐Sung , Oh Mi‐Kyeong
Published: July 2010

Background:  Facial flushing responses to drinking, because of intolerance to alcohol, are observed in some people, especially Asians. This study examined the role of flushing responses in the relationship between alcohol consumption and insulin resistance (IR).

Methods:  Participants in this cross‐sectional analysis included 624 Korean men (80 nondrinkers, 306 nonflushing drinkers, and 238 flushing drinkers) who were free of cardiovascular disease and diabetes. Data on the flushing response to drinking and alcohol consumption were collected from medical records. IR was estimated using the Homeostasis Model Assessment (HOMAIR). On the basis of comparisons with nondrinkers, the risk of IR according to the quantity of alcohol consumed per week was analyzed among nonflushers and flushers.

Results:  After adjusting for age, exercise status, smoking status, BMI, waist circumference, blood pressure, high‐density lipoprotein cholesterol, and triglycerides using a logistic regression model, we found a low risk of IR among nonflushers who consumed ≤4 drinks (1 drink = 14 g of alcohol) per week (OR = 0.3). In contrast, a higher risk of IR was associated with nonflushers who consumed >20 drinks per week (OR = 3.5). On the other hand, only a higher risk of IR was associated with flushers who consumed >12 drinks per week (>12 to 20 drinks: OR = 4.7; >20 drinks: OR = 3.5).

Conclusions:  The amount of drinking associated with the development of IR in flushers was lower than in nonflushers. Additionally, no positive effect of moderate drinking on IR was observed in flushers. The findings support acetaldehyde‐derived mechanisms in the development of alcohol‐related IR.
Coronary Left Main and Non‐Left Main Bifurcation Angles: How are the Angles Modified by Different Bifurcation Stenting Techniques?
Authors: GODINO COSMO , AL‐LAMEE RASHA , ROSA CLAUDIO LA , MORICI NUCCIA , LATIB AZEEM , IELASI ALFONSO , MARIO CARLO DI , SANGIORGI GIUSEPPE M. , COLOMBO ANTONIO
Published: July 2010

Background: Investigation of the correlation between bifurcation angles and outcomes is limited with discordant results. The aim of this study is to investigate left main (LM) and non‐left main (N‐LM) bifurcation angles and their modification after percutaneous coronary intervention (PCI). Measurement of all three angles adds to our understanding of bifurcation anatomy and the resultant effect of different stenting techniques.

Methods and Results: All three bifurcation angles were described according to the European Bifurcation Club definition: the A (proximal bifurcation angle), the B (distal bifurcation angle) and the C (main branch angle). Measurements were performed in 75 LM and 140 N‐LM bifurcations. In LM bifurcations baseline mean values of C, A, and B were 151°± 28°, 131°± 32°, and 78 ± 28°, respectively. In bifurcations with 2 stents the B significantly decreased by a mean of 10° (P = 0.003) and A increased by 10° (P = 0.006). Crush stenting significantly decreased B (A – 14°; P = 0.020) and increased A (A + 21°; P = 0.005), particularly non‐true bifurcations. In N‐LM bifurcations mean values for C, A, and B were 156°± 19°, 144°± 22°, and 60°± 20°, respectively. Similar to LM bifurcations, the B became narrower mainly at the expense of the A, which became wider. In both types of bifurcations the greatest variation in A and B was found following 2‐stent techniques performed in T‐shaped (≥70°) bifurcations.

Conclusions: In both LM and N‐LM bifurcations we found a significant difference in A and B pre‐ and post‐PCI. This difference was driven by the 2‐stent technique and was most evident with a baseline bifurcation angle ≥70°. The Crush technique caused the largest angle variation post‐procedure, particularly in non‐true LM bifurcations.(J Interven Cardiol 2010;23:382–393)
Macrophages heterogeneity in atherosclerosis – implications for therapy
Authors: Wilson Heather M.
Published: July 2010

Introduction

Current concepts in monocyte heterogeneity

Pro‐atherogenic role of plaque macrophages

Anti‐atherogenic role of plaque macrophages

Macrophage heterogeneity and in vitro classification

Macrophage heterogeneity within atherosclerotic plaques

Macrophage heterogeneity in obesity and    obesity‐associated disorders

Macrophage modulation by pathogens and tumours

Pharmacological modulation of macrophage function

Macrophages as a target to non‐invasively image vulnerable plaques

Summary

Atherosclerosis is a chronic inflammatory disease occurring within the artery wall and is an underlying cause of cardiovascular complications, including myocardial infarction, stroke and peripheral vascular disease. Its pathogenesis involves many immune cell types with a well accepted role for monocyte/macrophages. Cholesterol‐loaded macrophages are a characteristic feature of plaques and are major players in all stages of plaque development. As well as modulating lipid metabolism, macrophages secrete inflammatory cytokines, chemokines and reactive oxygen and nitrogen species that drive pathogenesis. They also produce proteases and tissue factor that contribute to plaque rupture and thrombosis. Macrophages are however heterogeneous cells and when appropriately activated, they phagocytose cytotoxic lipoproteins, clear apoptotic bodies, secrete anti‐inflammatory cytokines and synthesize matrix repair proteins that stabilize vulnerable plaques. Pharmacological modulation of macrophage activity therefore represents a potential therapeutic strategy for atherosclerosis. The aim of this review is to provide an overview of the current understanding of the different macrophage subsets and their monocyte precursors, and, the implications of these subsets for atherosclerosis. This will present a foundation for highlighting novel opportunities to exploit the heterogeneity of macrophages as important diagnostic and therapeutic targets for atherosclerosis and its associated diseases.
Paracetamol in early infancy: the risk of childhood allergy and asthma
Authors: Bakkeheim Egil , Mowinckel Peter , Carlsen Kai Håkon , Håland Geir , Carlsen Karin C Lødrup
Published: July 2010

Aim:  We investigated whether paracetamol exposure in pregnancy and until 6 months of age was associated with allergic disease in school children.

Methods:  In a prospective birth cohort study in Oslo, 1016 children included at birth were re‐investigated at 10 years. Paracetamol exposure in pregnancy and until 6 months of age was registered. Outcomes at 10 years included current asthma, a history of asthma, allergic sensitization and allergic rhinitis.

Results:  Maternal paracetamol use in the first trimester increased the risk for allergic rhinitis at 10 years OR (odds ratio) (95%CI) 2.30 (1.06, 4.97) in boys and girls. Paracetamol use until 6 months in girls increased the risk for allergic sensitization OR 2.20 (1.15, 4.22) and a history of asthma OR 2.20 (1.13, 4.30). The ORs for allergic sensitization and history of asthma in girls remained unchanged adjusting for upper or lower airway infections during the first 6 months of life.

Conclusion:  Paracetamol exposure in pregnancy was associated with allergic rhinitis, but not with asthma or allergic sensitization at 10 years of age. Paracetamol used until 6 months of age was associated with allergic sensitization and having a history of asthma in girls at 10 years of age, even considering concomitant airway infections.
Urinary aquaporin‐2 excretion during ibuprofen or indomethacin treatment in preterm infants with patent ductus arteriosus
Authors: Li Yanhong , Zelenina Marina , Plat‐Willson Geneviève , Marcoux Marie‐Odile , Aperia Anita , Casper Charlotte
Published: July 2010

Aim:  Water channel AQP2 is the target for vasopressin (AVP) and a major determinant of urinary concentrating capacity. In mature kidneys, prostaglandins counteract the effect of AVP on AQP2 expression at functional sites. We investigated whether disturbances in water homeostasis in infants with patent ductus arteriosus (PDA) treated with prostaglandin inhibitors can be attributed to activation of AQP2.

Methods:  In 53 infants with symptomatic PDA (gestational age 24–33 weeks), 30 receiving ibuprofen and 23 indomethacin starting at 2–15 days of life, clinical and biochemical data were collected before treatment and after each dose of the drugs. Urinary AQP2 was determined by dot immunoblotting.

Results:  Urinary AQP2 level and osmolality were decreased in both groups. Urinary osmolality was overall low and correlated inversely with fluid uptake. In ibuprofen group, there was no correlation of AQP2 level with urinary osmolality.

Conclusion:  There was no AQP2 upregulation in the infants. The low urinary osmolality and dissociation between urinary osmolality and urinary AQP2 level indicate that the fluid retention sometimes observed in PDA infants treated with prostaglandin inhibitors is not caused by increased levels of functional AQP2. Thus, knowledge about the renal physiology of the adult cannot always be transferred to the infant kidney.
Family Policy: Becoming a Field of Inquiry and Subfield of Social Policy
Authors: Bogenschneider Karen , Corbett Thomas J.
Published: July 2010

This decade review centers on 2 disconnects between rhetoric and reality. First, public investments in families continue to grow, yet family policy is still not a term widely used by policymakers or the public. Second, social science studies increased in number and sophistication, with some family sensitive and others policy relevant. Few focus on both, which is what is most needed if research is to inform family policy. In exploring these disconnects, we summarize recent trends in family policies and the influence of research on family policymaking. We suggest a rationale for family policy and illustrate its value using the examples of early childhood, welfare reform, and parent education policies. We conclude with suggested next steps.
Incontinence: Assessment, Diagnosis, and Management in Two Rehabilitation Units for Older People
Authors: Coffey Alice , McCarthy Geraldine , McCormack Brendan , Wright Jayne , Slater Paul
Published: July 2010

Background: Incontinence of both bladder and bowel is a major health care problem and adversely affects the lives of many people living at home or in health service facilities. The prevalence and severity of incontinence is a global concern that has, in recent years, prompted investigation across several countries. Current approaches to continence care indicate an emphasis on safety and reduction of risk, rather than on detailed individualised assessment and management.

Aim: To show approaches to assessment, diagnosis, and management of urinary and faecal incontinence in two rehabilitation settings for older people in Ireland. The study forms part of a larger 2‐year case study to identify the determinants of practice “context” that enable or hinder proactive approaches to promoting continence and the treatment of incontinence in rehabilitation settings for older people.

Method: The Royal College of Physicians Audit Scheme was used to record the assessment and management of urinary and faecal incontinence. This scheme also includes questions regarding resources available to enable effective continence management. Over 6 months, 220 patients who suffered from incontinence participated in two study sites: a 78‐bed rehabilitation unit in Northern Ireland and an 80‐bed rehabilitation unit in Southern Ireland.

Results: Findings indicated that 60% of incontinent patients had urinary incontinence, 3% faecal incontinence, and 37% mixed urinary and faecal incontinence; however, a specific continence assessment and specific rationale for treatment decisions or continuation of care were lacking. The focus was on continence containment rather than on proactive management. The examination of resources available for continence promotion and management showed that even though guidelines for continence management were available to staff in one unit, there was a dearth of appropriate education or support for staff in continence care.

Implications for Practice: Because incontinence remains an issue for older people and the clinical implications of sustained incontinence are multifaceted, strategies should focus on the development of practice towards evidence‐based multidisciplinary approaches to continence promotion and management.
Analysis of junior doctor supervision in Australasian emergency departments
Authors: Orman Scott A , Thornton Vanessa J
Published: July 2010

Background:  Supervision of junior doctors in ED is vital but limited literature exists on how it is provided.

Objective:  To assess Australasian ED supervision and review regional legislature supervision requirements.

Methods:  Between December 2008 and June 2009 emails containing a link to a cross‐sectional survey were sent to Directors of Emergency Medicine Training in all Australasian ED accredited for advanced training. Non‐responding ED were subsequently contacted by telephone or email. Regional legislature supervision requirements were obtained from postgraduate medical councils.

Results:  A total of 103 (98.1%) of 105 ED participated. Senior review in person was mandatory in 43.2% of ED for patients of PGY1 (postgraduate year 1 doctors) and 6.1% of ED for patients of PGY2 (P < 0.001). Of ED without mandatory review, 13% had written guidelines detailing which patients required review. When ED consultants were on‐site, they most commonly provided supervision in 60.2% of ED and shared supervision equally with registrars in 35.7% of ED; when consultants were off‐site registrars most commonly provided supervision in 87.6% of ED. Fewer major regional/rural base hospitals had 24 h PGY3 or above supervision than major referral and urban district hospitals (82.6% vs 100% and 100%, P < 0.01). Regional legislature requirements varied with no universal guidelines.

Conclusion:  There are significant differences between supervision requirements for PGY1 and PGY2. A minority of ED in Australasia do not have 24 h supervision by PGY3 or higher. Few ED have written guidelines for supervising PGY1 and PGY2. The majority of registrar supervision occurs without consultant oversight. Legislature requirements for supervision in ED are variable between regions.
Measuring secretion in chromaffin cells using electrophysiological and electrochemical methods
Authors: Borges R. , Camacho M. , Gillis K. D.
Published: July 2010

Our present understanding of exocytosis of catecholamines has benefited tremendously from the arrival of single‐cell electrochemical methods (amperometry and voltammetry), electrophysiological techniques (whole‐cell and patch capacitance) and from the combination of both techniques (patch amperometry). In this brief review, we will outline the strengths and limitations of amperometric and electrophysiological methods and highlight the major contribution obtained with the use of these techniques in chromaffin cells.
Actions Taken to Reduce Sodium Intake Among Adults With Self‐Reported Hypertension: HealthStyles Survey, 2005 and 2008
Authors: Ayala Carma , Tong Xin , Valderrama Amy , Ivy Andrae , Keenan Nora
Published: July 2010

J Clin Hypertens (Greenwich). 2010;12:793‐799. © 2010 Wiley Periodicals, Inc.

Consuming high amounts of dietary sodium is associated with hypertension. The authors analyzed the HealthStyles 2005 and 2008 survey for behaviors to lower blood pressure related to dietary sodium, including the reduction of sodium intake and reading food labels for sodium content among hypertensives. All estimates were based on self‐reported data. The relative percent change (RPC) in the prevalence of these behaviors between 2005 and 2008 was assessed. During the 3‐year period, there were increases in the prevalence of reducing dietary sodium (RPC=17.2%, 56.6% in 2008 vs 48.3% in 2005; P<.05) and reading food labels for sodium content (RPC=7.9%, 53.0% vs 49.1%; P<.05). In 2005, the proportion of hypertensive adults who reported reducing dietary sodium was higher for persons 65 years and older, for blacks, for those with income <$25,000, and for those with more than a high school education compared with those in their comparison groups. In 2008, those aged 65 years and older had the highest percentage, while Hispanics and blacks had essentially the same percentage for reducing sodium. Based on 2005 and 2008 HealthStyles surveys, about half of hypertensive patients reported reducing their intake of sodium and reading food labels for salt. Health care providers should emphasize the importance of knowing the daily recommended limit for dietary sodium to help adults lower this intake.
Limbal conjunctival plaques and idiopathic eosinophilic conjunctivitis
Authors: Wolfe J. E. , Utter M. E. , Boyle A. G. , Habecker P. L.
Published: July 2010

A 4‐year‐old Welsh pony crossbred gelding was examined for acute onset of blepharospasm, epiphora and corneal oedema. Ophthalmic examination identified 2 conjunctival plaques located near the superior limbus of the left eye. The plaques did not resolve following treatment with topical triple antibiotic ointment, topical atropine ointment and oral flunixin meglumine and therefore a conjunctival biopsy was performed. Histology of the biopsy resulted in a diagnosis of eosinophilic conjunctivitis, which was treated with a topical corticosteroid ointment. Plaques resolved after 73 days of therapy but lesions did not improve with concurrent treatment with anthelmintics early in the course of therapy. Failure to identify an aetiological agent led to a diagnosis of idiopathic eosinophilic conjunctivitis. The conjunctival plaques have not recurred in the 10 months following discontinuation of therapy.
Reduction of Particle Number and Mass Emissions of a Modern Off-Road Diesel Engine
Authors: Niemi Seppo , Pippola Jukka , Nousiainen Pekka , Laure´n Mika
Published: July 2010

The oxides of nitrogen (NOx) and particulate matter (PM) form the main challenge for diesel engine exhaust cleaning. Despite the emissions reduction, the fuel economy should be kept at a sufficient level to also prevent CO2 increase. In the present project, a turbocharged, inter-cooled, common-rail, direct-injection, off-road diesel engine, largely used in tractors, forest machines etc., is optimized to make the engine comply with the US EPA Tier 4i/4 emissions legislation. The present study focused on pulse turbocharging and open-flow or partial diesel particulate filter system (pDPF). PM mass and PM number concentrations were determined both up- and downstream the pDPF. The engine was operated according to the steady and transient non-road emissions cycles (NRSC, Non-Road Steady Cycle; NRTC, Non-Road Transient Cycle, respectively). The main aim of the current study was to reduce PM emissions since a catalyst based on SCR technology was selected for NOx removal. Clear benefits in PM emissions were achieved with pulse turbocharging, especially during the transient engine operation. A very slight increase in the brake specific NOx (BSNOx) was detected with both studied pulse manifolds while PM decreased by 20% or more. CO also decreased clearly with Pulse 1 but HC remained almost constant. The opacity peaks recorded during the NRTC measurement also decreased considerably compared with the baseline constant-pressure turbocharging. The pDPF also proved efficient both for particle number levels and PM mass. In steady-state engine operation, the DOC containing filter system removed exhaust CO and HC effectively. BSNOx also decreased slightly. The exhaust particle number generally decreased usually the more, the larger the particles. Over the transient cycle with the pDPF, the weighed PM decreased by 77% and was clearly below the US EPA Tier 4i limit. The filter also reduced smoke opacity peaks effectively. The BSNOx decreased more than in the steady cycle, as did CO and HC.
Slide Bearing Types for Combustion Engines Designed for Upcoming Emission Regulations
Authors: Langbein Falko , Loidl Matthias , Eberhard Alexander , Mergen Robert
Published: July 2010

Intelligent handling of our limited energy resources and the demand to reduce emissions are today the main drivers for developing efficient combustion engines. Therefore slide bearings and also other parts of the powertrain are facing major challenges caused by: Significantly increased operating pressure, temperature and sliding speed as well as the use of new lubricants and fuels. Furthermore, a ban of hazardous elements (e.g. lead, cadmium) in the applied materials is looming. With respect to above mentioned facts, the mechanical and tribological boundary conditions for bearings in future engines are subjected to change immensely. These changes can only be met by new lining materials and bearing types. From the standpoint of strength, the main critical factors are the soft phases — mainly tin and lead — added to both aluminum and copper based bearing alloys to obtain the necessary tribological behavior. Soft phases are limited in their temperature stability and in addition, lead is an environmental critical element and is restricted. For upcoming engine generations even novel aluminum-tin alloys will reach their performance limits and the classical leaded-bronze material as basis for tri-metal and sputter coatings can no longer cope with the life-time expectations. In addition, corrosion issues will come up due to new oil additives in truck and high speed engines. The present paper proposes, for the application in high speed and truck engines, new slide bearing types with appropriate characteristics and the desired performance required by engine designers: A high strength, thermally stable aluminum alloy with excellent mechanical properties by using re-crystallization inhibition mechanisms; a series of new solutions on the basis of a lead-free bronze linings having brilliant thermo-mechanical process capabilities resulting in high strength properties. Adequate tribological behavior is gained by combination of the new lining alloys with different surface layers. Fundamental working principles, development work and first application results of the new bearing types are presented in relation to existing solutions.
Experimental Investigation of an Organic Rankine Cycle Prototype Plant Being Developed to Boost the Electric Output of Gas Engine Power Stations
Authors: Ast Gabor , Kopecek Herbert , Gomez Jose , Huck Pierre , Frey Thomas , Wilmsen Bernd , Gruber Friedrich
Published: July 2010

With nowadays rising fuel prices and increasing regulations on CO2 emissions [1, 2] Organic Rankine Cycle (ORC) plants are potential candidates to utilize the waste heat of large stationary combustion engines and convert it into additional electricity, hence boosting the net electric output power and increase the efficiency of the overall power plant. ORCs have the potential to increase the engine net power output by up to 10% without additional fuel consumption. Here our group presents the experimental results of an ORC prototype plant [3]. The facility was designed to take about 250 kW of heat at about 100°C as an input and turn it into electric power of several kilowatts. A water boiler was used as heat source to simulate the hot engine coolant of a gas engine. Both, steady state system response and plant behavior at the complete operating envelope of cycle pump and turbine have been analyzed. The system response data shows linear behavior around the operating point for the most system outputs. Only pressure ratio over the expander and net electric efficiency demonstrate a nonlinear behavior. The plant operation maps reveal that respecting the typical boundary conditions still at least one degree of freedom is not constrained and can be used for operating conditions optimization.
Further Development and Experimental Analysis of a New Common Rail FIS Without Accumulator
Authors: Catania Andrea Emilio , Ferrari Alessandro
Published: July 2010

An innovative hydraulic layout for Common Rail (CR) fuel injection systems (FIS) without accumulator was further developed and assessed. The rail was removed and replaced by a high-pressure pipe junction to have faster dynamic system response during engine transients, smaller pressure induced stresses and reduced production costs. Compared to a commercial rail, whose internal volume ranges from 20 to 40 cm3, the junction provided a hydraulic capacitance of about 2 cm3 with the main function of connecting the pump delivery to the electroinjector feeding pipes. The modified injection system was realized and subjected to experimentation under engine-like working conditions on a high performance Moehwald-Bosch test bench. The injection performance of the new system with different hydraulic layouts was shown to be generally similar to those of a commercial CR system. Besides, for multiple injections, the new layout dynamics were substantially improved by a reduced dependence of the overall injected fuel amount on dwell-time (DT) during sequential injection events. This was achieved by selecting injector supplying pipes with an internal diameter and length out of the present production range. The results supported the findings that the rail capacitance was not a key parameter in pressure wave disturbance attenuation.
A Study on the Performance of Combustion in a HCCI Engine Using n-Heptane by a Multi-Zone Model
Authors: Guo Hongsheng , Li Hailin , Neill W. Stuart
Published: July 2010

A study of n-heptane combustion in an HCCI engine was carried out by a multi-zone numerical simulation that covers a complete engine cycle. A reaction mechanism that includes 177 chemical species and 1638 reactions was used. The results of the numerical simulations were compared to existing experimental data for a range of air/fuel ratios, compression ratios and engine speeds. It is shown that the numerical simulation is able to reasonably capture the experimental cylinder pressure data over a wide range of operation conditions. It also provides a qualitative trend of CO emissions. The numerical simulation overpredicted the combustion at some operating conditions, such as at extremely high air/fuel ratios and higher engine speeds. Some differences were observed between the experimental and numerical data for NOX emissions. The numerical simulation predicted a monotonic decrease in NOX emissions as air/fuel ratio increased or compression ratio decreased, while an increase in NOX emissions was observed experimentally when combustion became very weak at extremely high air/fuel ratios or low compression ratios. It is suggested that further experiments and numerical simulations should be performed to explain this discrepancy.
Analysis of In-Plane Modal Characteristics of an Annular Disk With Multiple Point Supports
Authors: Bashmal S. , Bhat R. , Rakheja S.
Published: July 2010

In-plane free vibrations of an isotropic, elastic annular disk constrained at some points on the inner and outer boundaries are investigated. The presented study is relevant to various practical problems including disks clamped by bolts along the inner and outer edges or the railway wheel vibrations. The boundary characteristic orthogonal polynomials are employed in the Rayleigh-Ritz method to obtain the frequency parameters and the associated mode shapes. The boundary characteristic orthogonal polynomials are generated for the free boundary conditions of the disk while artificial springs are used to realize clamped conditions at discrete points. The frequency parameters for different point constraint conditions are evaluated and compared with those computed from a finite element model to demonstrate the validity of the proposed method. The computed mode shapes are presented for a disk with different point constraints at the inner and outer boundaries to demonstrate the free in-plane vibration behavior of the disk. Results show that addition of point supports causes some of the modes to split into two different frequencies with different mode shapes. The effects of different orientations of multiple point supports on the frequency parameters and mode shapes are also discussed.
Application of Neural Networks for Estimation of Tyre/Road Forces
Authors: Boada Maria Jesus L. , Boada Beatriz L. , Garcia-Pozuelo Daniel , Diaz Vicente
Published: July 2010

The behaviour of the tyre plays an important role in the vehicle handling. Thus for the analysis of vehicles and road safety, it is necessary to take into account the forces and moments generated at contact match. An accurate tyre model that estimates these forces and moments it is highly essential for the studies of vehicle dynamics and control. Much of the tyre models neglect the coupling of the forces in different directions. They describe the tyre-forces generated at the pure-slip conditions of braking, driving or cornering. Nevertheless, a steering maneuver during braking, generally, decreases the braking stiffness, the longitudinal peak force, and its corresponding slip value. A model for the interaction between the slip in both directions is therefore inevitable for more advanced vehicle simulations. In this work, a recursive lazy learning method based on neural networks is proposed in order to model the tyre force generation at combined slip. Experimental results obtained after training show that the neural model learns to model the tyre behaviour without difficulty.
Studying Your Students as They Learn: A Case Study of CAD Education
Authors: Hamade R. F.
Published: July 2010

Having observed mechanical engineering seniors at the American University of Beirut (AUB) go about learning computer-aided design (CAD) in a formal setting, the instructors always wondered why some students acquire CAD skills with relative ease while some others seem to struggle. For this reason, a methodical study was launched in order to address this issue. Hence, and in order to “study the students as they learn” was accomplished by following 74 mechanical engineering seniors (it took three academic years including AY 2008–09 in order to have access to this relatively large number of trainees) as they went through a semester-long formal training on a commercial computer-aided design (CAD) package (Pro/Engineer, version Wildfire). The study methodically explored the trainees’: (1) technical background, (2) behavioral attributes (willingness-to-learn), and their (3) learning preferences. Investigating the technical background included quantifying the trainees’ relevant technical competencies specifically: basic math foundation, advanced math foundation, CAD-related mathematical foundation, computer science and engineering foundation, methodologies related to CAD, graphics foundation, and mechanical design foundation. Determining the trainees’ behavioral attributes included exploring their initial attitude towards learning of CAD, perception and imagination, and gauging their actual behavior (practice and CAD skills learned) throughout the training. Trainees’ learning styles were determined according to the index of learning styles, ILS [1]. Furthermore, and in order to assess the trainees’ progress in CAD knowledge acquisition, competency tests were conducted at four intervals throughout the semester-long study (2, 4, 7, and 12 weeks). The assessment involved hands-on building of CAD test parts of comparable complexity. At the conclusion of the study, statistical methods were used to correlate the trainees’ attributes with their monitored performance. Only a fraction (17 out of a class of 74 trainees or about one in four) of the trainees were found to fit the “star CAD trainee” mold which was defined in this study as someone who is fast on the tube as well as perceptive enough to be see through the procedure of building progressively more sophisticated CAD models. A profile of this “star CAD trainee” character emerges as an individual who is technically competent and perceptive, with personal drive and positive attitude, and who possesses active, sensor, sequential and visualizing learning styles.
Multi-Objective Optimization of Pin-Fin Heatsinks
Authors: Horiuchi Keisuke , Nishihara Atsuo , Sugimura Kazuyuki
Published: July 2010

The multi-objective optimization of pin-fin heatsinks using a Kriging approximation model is presented based on systematic experimental results. Thermal resistance and pressure drop are the objective functions in this study. Pareto solutions to the objective functions are illustrated. We derived the design rules for the diameter, height, and pitches for the uniform staggered arrays of pin-fin heatsinks by correlating the objective functions with design variables. We also analyzed the contribution of all design variables to the thermal resistance as well as the pressure drop. We found that both the thermal resistance and the pressure drop are the most sensitive to the ratio of transverse pitch to pin-fin diameter.
An Automated Cyclic Particle Extractor
Authors: Chuang Han-Sheng , Wereley Steven T. , Jacobson Stephen C.
Published: July 2010

Based on diffusion mechanism, a program-controlled cyclic particle extraction on an integrated PDMS microfluidic platform is presented. The platform comprises on-chip pneumatic peristaltic pumps and valves connected to a PC-based relay board, hence allowing programmable manipulations. The main concept is cycling a sample stream along with an extraction stream multiple times to enhance the particle separation. A sample solution containing 3-μm and 0.5-μm particles was utilized to demonstrate the process. The average flow rate was 4.75 mm/s and the extraction channel length was 84.3 mm. The relatively accumulative concentration for the 0.5-μm particle was 7.52% at the 1st cycle and became 37.99% at the 10th cycle. The result shows an expected improvement of particle concentration after the cyclic extraction. Higher efficiency can be achieved with more cycles.
Numerical Modeling and Experimental Study of Hot-Embossing Process for Manufacturing of Microcomponents
Authors: Marcotte Jean-Philippe , Kabanemi Kalonji K. , He´tu Jean-Franc¸ois
Published: July 2010

Hot embossing is a compression molding technique used for high replication accuracy of small features. One of the most sensitive phases of the process is the de-embossing stage during which the patterned part has to be demolded. In this paper, the demolding stage is considered as a frictional contact problem between a rigid mold insert and a viscoelastic polymer sheet as it deforms and cools inside a mold under an applied force. The contact is modeled with a modified Coulomb’s law of dry friction while a generalized Maxwell model is used to describe the polymer behavior during embossing, cooling and de-embossing stages. The heat transfer between the mold insert and the patterned polymer sheet is solved through a domain decomposition method. A finite element approximation based on a penalized technique is proposed and analyzed. The purpose of this modeling approach is to predict dimensional stability and residual shape of microcomponents in the hot embossing process. Such a prediction will allow one to assign appropriate processing conditions that minimize geometrical imperfections and increase replication accuracy.
Riding Mower Injury Prevention (An Alternative Design for No-Mow-In-Reverse)
Authors: Ferrone Christopher W. , Przybyla Julie A. , Orseske Matthew T.
Published: July 2010

Overwhelmingly, research indicates that there are thousands of injuries each year related to the use of lawn mowers. Riding mowers have specific injury scenarios such as when a child is run over by the riding lawn mower when it is in reverse with the cutting blades engaged. In conjunction with ANSI B71.1 implemented in 1986, various designs have been employed to attempt to reduce or eliminate this injury pattern. An alternative design has been built which incorporates both mechanical means and human factors methods to accomplish this goal. This paper will outline the existing commercially available designsA as well as the authors’ alternative design by comparing each design feature and its corresponding safety philosophy.
Fire: Cause and Origin of Heavy Vehicles (Mechanical and Forensic Methods)
Authors: Ferrone Christopher W.
Published: July 2010

The occurrence of large scale fires involving heavy vehicles and equipment remains a problem. Methods need to be developed in order to determine the cause and origin of these fires. A method combining mechanical engineering, basic mechanics along with forensic techniques and investigation standards has been developed, in a single source format, to assist in determining the cause of large scale fires. Techniques used in the overall method are; the machines’ mechanical and electrical function, the scenario of facts, operational profile, prior maintenance, the construction of the machine and reconstruction of the accident. This paper will use individual case study examples to illustrate the techniques to be used in the analysis.
Low Cost Fabrication of Thin Film Carbon Nanotubes With Various Transparencies
Authors: Tantang H. , Loh C. L. , Ong J. Y. , Wei J. , Li L. J.
Published: July 2010

Carbon nanotube was known for years to possess extraordinary properties, one of them is its high mobility and current carrying capability. Hence the most direct application that could make use this property would be electrodes. The main advantages of making use of carbon nanotube as electrodes are: low material cost due to abundant raw materials, solution process able, and could be used for application requiring transparencies. However, despite its simple procedure, there are many fabrication parameters that require thorough investigation, starting from selection of raw materials, solubilization methods, and deposition methods. In addition to that there are post fabrication steps that need to be carried out to obtain desirable properties of electrodes. Herein, we report fabrication method of carbon nanotube electrodes using air-gun spraying. Fabrication parameters and post fabrication steps were investigated to obtain high conductivity electrodes. Electrodes with different range of transparencies was fabricated starting from 85% transmittance at 550 nm, which could be used as replacement of common transparent electrodes (i.e ITO), up to totally opaque films, which can be used as interconnects.
Homoclinic Orbit Bifurcation of a Rotating Truncated Conical Shell
Authors: Dai Liming , Chen Changping
Published: July 2010

This is a study on Homoclinic bifurcation and subharmonic bifurcation of a truncated conical shallow shell rotating around a single axle and excited by a transverse periodic load. A systematic numerical approach is used to study the nonlinear motion of the system. The conditions under which bifurcations occur are determined on the basis of the characteristics of the rotating shell. Hamilton’s singular distributions are also investigated in details.
Feasibility Assessment of a Kalman Filter Approach to Fault Detection and Fault-Tolerance in a Highly Unstable System: The RIT Heart Pump
Authors: Gillespie Erin M. , Walter Wayne
Published: July 2010

The purpose of this project is to assess the feasibility of a Kalman Filter approach for fault detection in a highly unstable system, specifically a heart pump that is currently under development at RIT. Simulations and experimental work were completed to determine the effects of possible position sensor fault conditions on the system; that information was then used in conjunction with a pair of Kalman filters to create a method of detecting faults and providing fault-tolerant operation. The estimator system was designed and tested using SIMULINK™. The simulations showed the filters were able to calculate and remove bias caused by any type of position sensor error, provided the estimated plant model is nearly identical to the actual plant model. Sensitivity analysis showed that the fault detection/fault-tolerance method is extremely sensitive to discrepancies between the estimated plant model and actual pump behavior. Consequently, it is considered unfeasible for implementation on a real system. Experimental results confirmed these findings, demonstrating the drawbacks of model-based fault detection and tolerance methods.
Effect of Textured Hydrophobic Surfaces on Microchannel Flow
Authors: Ogata Satoshi , Shimizu Keigo
Published: July 2010

We studied the effect of textured hydrophobic surfaces on drag reduction in Newtonian laminar flow through a rectangular channel. Fine fabrication was given to the test wall surfaces so that the groove pattern and the groove area ratio may be changed methodically, and their surfaces are coated with PTFE. Drag reduction was estimated by pressure loss measurement in 0.5×5 mm and 12×12 mm channels. Visualization experiment was carried out to reveal a mechanism of drag reduction from the form of air-water interface standpoint. A series of experiments showed that the air-water contact area ratio and the air layer thickness influence the drag reduction, and the maximum drag reduction ratio is 15.6%.
Nonlinear Static Research of an Electrically Actuated Piezoelectric Laminated Microbeam
Authors: Chen Changping , Jiang Yejie , Dai Liming
Published: July 2010

The paper presents a nonlinear static research for an electrically actuated piezoelectric laminated micro-beam. On the basis of the Euler-Bernoulli hypothesis, and the responses under electric force [a purely direct current (DC)] are investigated. By using the Taylor series expansion, a set of governing equations of nonlinear integro-differential type is derived. Then using the Galerkin method, an analytical is presented. Numerical examples show, when a purely DC is applied, there exist an instantaneous pull-in voltage, the effect of the pull-in phenomenon have the relation not with elastic parameter but with voltage on the piezoelectric layer.
Validation of an Acoustic Finite Element Model of an Automobile Passenger Compartment
Authors: Lee Sangyun , Park Kwangseo , Sung Shung H. , Nefske Donald J.
Published: July 2010

An acoustic finite-element model of an automobile passenger compartment that represents the more complicated vehicle interior acoustic characteristics is developed and experimentally assessed using loudspeaker excitation. The acoustic finite-element model represents the passenger compartment cavity, trunk compartment cavity, front and rear seats, parcel shelf, door volumes, and IP (Instrument Panel) volume. The model accounts for the coupling between the compartment cavity and trunk cavity through the rear seat and parcel shelf, and the coupling between the compartment cavity and the door and IP panel volumes. Modal analysis tests of a vehicle were conducted using loudspeaker excitation to identify the compartment cavity modes and sound pressure response at a large number of interior locations. Comparisons of the predicted versus measured mode frequencies, mode shapes, and sound pressure response at the occupant ear locations are made to assess the accuracy of the model to 400 Hz.
Numerical Simulation of Boundary Layer Separation Flow for Airfoil in a Wind Turbine
Authors: Liao Quan , Cui Wenzhi , Li Longjian , Zhang Yihua
Published: July 2010

The characteristic of static stall for an airfoil is very important for the design of wind turbine. As long as the detailed information of boundary layer separation flow around an airfoil is obtained, the static stall characteristics could be predicted appropriately. In this paper, both two dimensional (2D) and three dimensional (3D) mathematical models are implemented to simulate fluid flow around a NREL S809 airfoil. The steady state compressible Reynolds-Averaged Navier-Stokes equations are adopted and solved numerically in this paper. Both one-equation and two-equation turbulence models (i.e., Spalart-Allmaras and k-ω Shear Stress Transport models) are adopted, respectively, to solve the turbulent viscosity in this paper. The simulation results show that more detailed vortex structures are obtained by using 3D Spalart-Allmaras turbulence model at high attack angle as compared to the two-equation k-ω SST turbulence model, and the obtained aerodynamic performance of an airfoil with Spalart-Allmaras model agrees well with the available experimental data. Therefore, it seems that the 3D Spalart-Allmaras turbulence model is more capable to demonstrate the 3D characteristics of boundary layer separation flow than the k-ω SST model, and it is more efficient to predict the characteristics of static stall for the airfoil. Meanwhile, the simulation results also reveal that the 3D characteristics of separation flow play a very important role for the aerodynamic performance of airfoil after the static stall, and then the 2D mathematical model is no longer suitable to simulate the boundary layer separation flow around the airfoil.
A New Lattice Boltzmann Model for Phase Transition Process
Authors: Li Longjian , Zeng Jianbang , Liao Quan , Cui Wenzhi
Published: July 2010

A new lattice Boltzmann model, which is based on Shan-Chen (SC) model, is proposed to describe liquid-vapor phase transitions. The new model is validated through simulation of the one-component phase transition process. Compared with the simulation results of van der Waals fluid and the Maxwell equal-area construction, the results of new model are closer to the analytical solutions than those of SC model and Zhang model. Since the range of temperature and the maximum density ratio are increased, and the value of maximum spurious current is between those of SC and Zhang models, it is believed that this new model has better stability than SC and Zhang models. Therefore, the application scope of this new model is expanded. According to the principle of corresponding states in Engineering Thermodynamics, the simulations of water and ammonia phase transition process are implemented by using this new model with different equations of state. Compared to the experimental data of water and ammonia, the results show that the Peng-Robinson equation of state is more suitable to describe the water, ammonia and other substances phase transition process. Therefore, these simulation results have great significance for the real engineering applications.
Dynamic Modeling of the Gearbox Transmission for the Wind Turbine
Authors: Ma Chao-feng , Liu Kai , Cui Ya-hui , Liang Wen-hong
Published: July 2010

In this paper, the dynamic model of the gearbox transmission for the wind turbine is proposed. The influence factor method is used to derive of the system’s dynamic equations, the natural characteristics of the transmission are obtained and the results are discussed. Finally, the influence of basic parts’ moment inertia on the natural characteristic is analyzed.
A Three-Dimensional Finite Element Stress Analysis and Strength Prediction of CFRP Adhesive Laminated Plates Subjected to Static and Impact Out-of-Plane Loadings
Authors: Noshita Yukiya , Sawa Toshiyuki , Omiya Yuya
Published: July 2010

Stress distributions in CFRP adhesive laminated plates subjected to static and impact out-of-plane loadings are analyzed using a three-dimensional finite-element method (FEM). For establishing an optimum design method of the laminated plates, the effects of some factors are examined. As the results, it is found that the maximum value of the von Mises equivalent stress σ eqv occurs at the edge of the CFRP’s interfaces. The maximum value of interface shear stress r i at CFRP interface decreases as the reinforced Young’s modulus and the thickness increases. However, the maximum value of σ eqv at the adhesive layer decreases as the reinforced Young’s modulus and the thickness decreases. In addition, the maximum value of r i at the CFRP’s interface of lower reinforced laminates under impact loadings shows opposite characteristics to those under static loadings. For verification of the FEM calculations, experiments were carried out to measure the strains at the interfaces and the laminates plates strengths. Concerning strain and strength prediction based on von Mises equivalent stress, fairly good agreements were found between the numerical and the experimental results. The FEM results of impacted strain are in fairly good consistent with the measured results. Discussion is made on the effects of some factors on interface stress distributions.