bluuebunny/crossref_metadata_2025 huggingface dataset:
Phenotypes of obstructive lung disease
Authors: Janson C.
Published: September 2008

Recently, there has been much emphasis on the fact that there are many different phenotypes in asthma and chronic obstructive pulmonary disease (COPD). The aim of this review is to investigate some aspects of phenotyping in these two diseases.

Epidemiological studies show a quite different risk factor pattern in allergic and non‐allergic asthma. Several studies also indicated that there are pathophysiological differences between these two types of asthma: such as eosinophil inflammation in allergic and neutrophil predominance in non‐allergic asthma. Neutrophil inflammation may also be a marker of severe asthma. At least one study indicates that non‐allergic asthmatics are less responsive to inhaled corticosteroids than allergic asthmatics. Recently, it has been emphasized that COPD also has manifestations other than lung function decline and that this also needs to be taken into account in severity characterisation. Dyspnea, weight loss, psychological status and co‐morbidity are factors that seem to be of large prognostic importance independently of the level of airflow obstruction in COPD.

Progress has been made in understanding how asthma develops, but effective measures for primary preventions is still lacking. Better phenotyping in asthma will hopefully enable us to make progress in this area. Phenotyping is also important for assessment of prognosis in both asthma and COPD.

Please cite this paper as: Janson C. Phenotypes of obstructive lung disease. The Clinical Respiratory Journal 2008; 2: 88–91.
Economics of COPD: literature review and experiences from field work
Authors: Nielsen R. , Klemmetsby M. , Gulsvik A.
Published: September 2008

Introduction:  The burden of diseases should be described in terms of costs. The available literature gives imprecise estimates of costs of chronic obstructive pulmonary disease (COPD) in the Nordic populations. Previous studies have methodological weaknesses related to choice of disease criteria, the use of highly selected populations and insufficient specification of the cost process. There are no robust estimates concerning the economics of COPD in Norway.

Methods:  We have conducted a 1 year follow‐up cost of illness study in a general population, recruiting eversmoking Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 2+ COPD patients and eversmokers without COPD. We have used diaries to recollect data, and comprehensive questionnaires to cover all costs of COPD.

Results:  The main challenges were the participants' unwillingness to complete diaries, the large amount of information and the logistics related to following up 476 individuals on four occasions during one year.

Conclusions:  We doubt the effect of diaries. However, we recommend a detailed planning of logistics and to emphasize main cost drivers.

Please cite this paper as: Nielsen R, Klemmetsby M and Gulsvik A. Economics of COPD: literature review and experiences from field work. The Clinical Respiratory Journal 2008; 2: 104–110.
Asthma in school age: prevalence and risk factors by time and by age
Authors: Bjerg A. , Rönmark E.
Published: September 2008

Background:  Childhood is the most important age for asthma development. Recent reports indicate that the prevalence of asthma in children has plateaued after having increased for decades.

Aims:  To study prevalence and risk factor patterns of asthma by age and by time.

Methods:  In 1996, all children in grade 1–2 (age 7–8) in three cities in Northern Sweden were invited to an expanded International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. A total of 3430 children (97%) participated yearly until 2000 (age 11–12). A subset (n = 2454) was invited to skin‐prick testing in 1996 and 2000 with 88% and 90% participation. In 2006, another cohort (n = 2704) was identified and studied by identical methods with 96% participation. A total of 1700 children (90% of invited) were skin‐prick tested.

Results and comments:  From age 7–8 to 11–12, the prevalence of physician‐diagnosed asthma increased, 5.7%–7.7% (P < 0.01) while current wheeze decreased, 11.7%–9.4% (P < 0.01), indicating a less diverse spectrum of symptoms with age. The yearly remission from asthma was 10% (lasting remission 5%), largely determined by allergic sensitisation. Allergic sensitisation (OR 5) and a family history of asthma (OR 3) were important risk factors for asthma at age 7–8 and 11–12. However, several other significant risk factors at age 7–8 (low birth weight, respiratory infections and house dampness) lost importance until age 11–12. Maternal and paternal asthma were equally important risk factors (OR 3–4) at age 7–8. Sibling asthma was only a marker of parental disease.

Future perspectives:  Through comparison with the 2006 cohort, trends in prevalence and in risk factors from 1996 to 2006 will be studied.

Please cite this paper as: Bjerg A and Rönmark E. Asthma in school age: prevalence and risk factors by time and by age. The Clinical Respiratory Journal 2008; 2: 123–126.
FinEsS‐Stockholm and the Stockholm adult asthma study
Authors: Ekerljung L. , Lundbäck B.
Published: September 2008

Two major studies on asthma and respiratory symptoms are presently in progress in Stockholm. The FinEsS‐studies has been ongoing since 1996, with a follow‐up study preformed in 2006 and a new cohort selected in 2007. The FinEsS studies focus on prevalence and incidence of asthma and respiratory symptoms in a general population. Clinical follow‐up surveys will also target COPD. Further aims include remission and relapse of disease and symptoms and their determinants. The Stockholm adult Asthma Study (SaAS) began in the spring of 2007 and data is being collected presently. The SaAS study focus on the medical care and medication given to asthmatics in Stockholm, and the study population consists of asthmatics found in the two Swedish cohort studies.

Please cite this paper as: Ekerljung L and Lundbäck B. FinEsS‐Stockholm and the Stockholm adult asthma study. The Clinical Respiratory Journal 2008; 2: 127–128.
Comparison of Treatment Result and Compliance between Private Practice Medicaid and Non‐Medicaid Orthodontic Patients – A Brief Communication
Authors: Dickens Steven , Beane Richard A. , Caplan Daniel J. , Vann, Jr. William
Published: September 2008

Treatment result and compliance for orthodontic Medicaid patients were assessed and compared to non‐Medicaid patients of similar initial severity. All 55 North Carolina practices providing orthodontic treatment covered by Medicaid were asked to submit their last five Medicaid cases and five non‐Medicaid cases of similar initial treatment complexity. Nine practices agreed to participate. Initial models, final models, and progress notes were obtained for all subjects. Casts were scored using the Peer Assessment Rating (PAR) Index to assess initial and posttreatment orthodontic status, and progress notes were reviewed for compliance data. No clinically important differences were seen between the Medicaid and non‐Medicaid groups with respect to initial PAR, final PAR, percent PAR reduction, broken appointments, broken appliances, or poor oral hygiene. In this study, Medicaid and non‐Medicaid patients did not differ substantially with respect to effectiveness of treatment received or their compliance with treatment.
Isolation and characterization of microsatellite markers in an endemic Hawaiian planthopper (Nesosydne chambersi: Delphacidae)
Authors: GOODMAN KARI ROESCH , MORRIS VERONICA RUTH FRANCO , WELTER STEPHEN C. , RODERICK GEORGE K.
Published: September 2008

We have isolated and characterized 17 microsatellite loci for the endemic Hawaiian planthopper Nesosydne chambersi (Delphacidae), a member of a large Hawaiian Nesosydne radiation. Thirty individuals from one population and 10 individuals from two populations across the species’ range were tested to investigate polymorphism. The observed loci contained two to nine alleles per locus. Expected heterozygosity within this species ranged from 0.2 to 0.85. These markers will be used to assess intraspecific differentiation and population structure within N. chambersi.
Comparison of anterior chamber depth measurements taken with the Pentacam, Orbscan IIz and IOLMaster in myopic and emmetropic eyes
Authors: Utine Canan Asli , Altin Feyza , Cakir Hanefi , Perente Irfan
Published: September 2008

Purpose:  This study determined to assess the degree of agreement between anterior chamber depth (ACD) measurements obtained using three different devices and to analyse the relationship between ACD and spherical equivalent (SE) refraction.

Methods:  In this cross‐sectional study, 42 eyes of 42 patients with a mean SE of − 4.69 ± 4.61 D (range 0.00 D to − 14.88 D) were analysed. Measurements of ACD between the corneal epithelium and the anterior surface of the crystalline lens, obtained using the Pentacam, Orbscan IIz and IOLMaster, were compared. The relationships between SE and ACD measurements obtained with different devices were also investigated. The results were analysed using Bland−Altman analyses, single‐sample t‐test and Pearson’s correlation test.

Results:  Orbscan ACD measurements were an average of 0.05 mm less than Pentacam measurements (p = 0.01). IOLMaster measurements were an average of 0.06 mm less than Orbscan measurements (p < 0.001). None of the ACD values measured by any of the devices were correlated with increasing SE (p > 0.05 for all). There was a weak positive correlation between SE and the difference in ACD measurements with Pentacam and Orbscan (p = 0.04); however, the differences between Pentacam and IOLMaster ACD measurements and Orbscan and IOLMaster ACD measurements seemed to be independent of SE (p = 0.17 and p = 0.54, respectively).

Conclusions:  The ACD in clinically normal eyes is measured differently by various non‐ultrasonic devices. However, the observed mean error between these modalities is too small to create any noticeable difference in refractive outcome. No significant relationship was found between SE and ACD measurements obtained by Pentacam, Orbscan or IOLMaster.
The role of optical coherence tomography in the detection of pituitary adenoma
Authors: Johansson Charlotta , Lindblom Bertil
Published: September 2008

Purpose:  To analyse retinal nerve fibre layer (RNFL) thickness in eyes with compression of the optic chiasm by a pituitary adenoma. RNFL thickness was analysed with optical coherence tomography (OCT) and compared to visual field measurements using high‐pass resolution perimetry (HRP).

Methods:  Sixteen eyes from eight patients with pituitary adenoma were studied. All had bitemporal visual field depression caused by compression of the optic chiasm. Patients were submitted to an ophthalmic examination more than 14 months after surgery (seven patients had undergone trans‐sphenoidal and one trans‐cranial adenomectomy). The examination included HRP, fundus photography and measurement of the peripapillar RNFL thickness using OCT.

Results:  In spite of temporal visual field depression, not all eyes showed reduced RNFL thickness by OCT. This was also true for some eyes in which RNFL was judged to be reduced on fundus photographs. Contrary to our expectations, RNFL thickness in the nasal quadrant was normal in nine of the 16 eyes. Corresponding figures for the superior, inferior and temporal quadrants were eight, six and five, respectively. The overall RNFL thickness, as measured by OCT, did not correlate well with neural capacity, which is an index of remaining retino‐cortical neural channels in HRP.

Conclusion:  RNFL thickness as measured with OCT was reduced in most, but not all, eyes with temporal field depression caused by chiasmal compression. The pattern of RNFL loss did not correlate well with the visual field defect. Sensitivity of RNFL thickness measurement in OCT was low. The method has limited value in the diagnosis of pituitary tumour compression.
Chaotic Vibrations of Sector-Type Spherical Shells
Authors: Krysko A. V. , Awrejcewicz J. , Papkova I. V.
Published: September 2008

In this work, chaotic vibrations of shallow sector-type spherical shells are studied. A sector-type shallow shell is understood as a shell defined by a sector with associated boundary conditions and obtained by cutting a spherical shell for a given angle θk, or it is a sector of a shallow spherical cap associated with the mentioned angle. Both static stability and complex nonlinear dynamics of the mentioned mechanical objects subjected to transversal uniformly distributed sign-changeable load are analyzed, and the so-called vibration charts and scales regarding the chosen control parameters are reported. In particular, scenarios of transition from regular to chaotic dynamics of the mentioned shells are investigated. A novel method to control chaotic dynamics of the studied flexible spherical shells driven by transversal sign-changeable load via synchronized action of the sign-changeable antitorque is proposed and applied. All investigations are carried out within the fields of qualitative theory of differential equations and nonlinear dynamics.
Unsteady Hydromagnetic Generalized Couette Flow of a Non-Newtonian Fluid With Heat Transfer Between Parallel Porous Plates
Authors: Attia Hazem Ali , Sayed-Ahmed Mohamed Eissa
Published: September 2008

The unsteady magnetohydrodynamics flow of an electrically conducting viscous incompressible non-Newtonian Casson fluid bounded by two parallel nonconducting porous plates is studied with heat transfer considering the Hall effect. An external uniform magnetic field is applied perpendicular to the plates and the fluid motion is subjected to a uniform suction and injection. The lower plate is stationary and the upper plate is suddenly set into motion and simultaneously suddenly isothermally heated to a temperature other than the lower plate temperature. Numerical solutions are obtained for the governing momentum and energy equations taking the Joule and viscous dissipations into consideration. The effect of the Hall term, the parameter describing the non-Newtonian behavior, and the velocity of suction and injection on both the velocity and temperature distributions are studied.
Solutions for Transient Heat Conduction With Solid Body Motion and Convective Boundary Conditions
Authors: McMasters Robert L. , Beck James V.
Published: September 2008

The analytical solution for the problem of transient thermal conduction with solid body movement is developed for a parallelepiped with convective boundary conditions. An effective transformation scheme is used to eliminate the flow terms. The solution uses Green’s functions containing convolution-type integrals, which involve integration over a dummy time, referred to as “cotime.” Two types of Green’s functions are used: one for short cotimes comes from the Laplace transform and the other for long cotimes from the method of separation of variables. A primary advantage of this method is that it incorporates internal verification of the numerical results by varying the partition time between the short and long components. In some cases, the long-time solution requires a zeroth term in the summation, which does not occur when solid body motion is not present. The existence of this zeroth term depends on the magnitude of the heat transfer coefficient associated with the convective boundary condition. An example is given for a two-dimensional case involving both prescribed temperature and convective boundary conditions. Comprehensive tables are also provided for the nine possible combinations of boundary conditions in each dimension.
Flush-Mounted Steady-Periodic Heated Film With Application to Shear-Stress Measurement
Authors: Cole Kevin D.
Published: September 2008

Surface-mounted heated films have been used for fluid-flow measurement for many years. Recently unsteady heating of such surface films has been explored experimentally. In this paper steady-periodic heating of a surface-mounted film is studied analytically. Wall effects and axial heat conduction in the fluid are included. The temperature is found as an exact integral expression constructed from separate Green’s function formulations in the fluid flow and in the solid wall that are matched at the fluid-solid interface. Results for temperature, obtained by quadrature, are reported for several flow speeds and several steady-periodic frequencies. The results show that steady-periodic heating has potential for shear-stress measurement because the heating frequency may be tuned to maximize the temperature response at the shear stress of interest. Thermal calibration of these sensors is discussed, and simulated calibration curves are given.
Cardiac Alternans Arising From an Unfolded Border-Collision
Bifurcation
Authors: Zhao Xiaopeng , Schaeffer David G. , Berger Carolyn M. , Krassowska Wanda , Gauthier Daniel J.
Published: September 2008

Following an electrical stimulus, the transmembrane voltage of cardiac tissue rises rapidly and remains at a constant value before returning to the resting value, a phenomenon known as an action potential. When the pacing rate of a periodic train of stimuli is increased above a critical value, the action potential undergoes a period-doubling bifurcation, where the resulting alternation of the action potential duration is known as alternans in medical literature. Existing cardiac models treat alternans either as a smooth or as a border-collision bifurcation. However, recent experiments in paced cardiac tissue reveal that the bifurcation to alternans exhibits hybrid smooth∕nonsmooth behaviors, which can be qualitatively described by a model of so-called unfolded border-collision bifurcation. In this paper, we obtain analytical solutions of the unfolded border-collision model and use it to explore the crossover between smooth and nonsmooth behaviors. Our analysis shows that the hybrid smooth∕nonsmooth behavior is due to large variations in the system’s properties over a small interval of the bifurcation parameter, providing guidance for the development of future models.
Generalization of the Energetic Coefficient of Restitution for Contacts in Multibody Systems
Authors: Najafabadi Seyed Ali Modarres , Kövecses József , Angeles Jorge
Published: September 2008

This paper introduces a new interpretation of the energetic coefficient of restitution, especially applicable to contact involving multibody systems. This interpretation generalizes the concept of the energetic coefficient of restitution and allows for consideration of simultaneous multiple-point contact scenarios. Such a generalization is obtained by an analysis of energy absorption and restitution during impact, using a decomposition technique, which exactly decouples the kinetic energy associated with the normal and tangential directions of the contact pairs. The main advantages of the new definition and its potential applications are highlighted.
Stabilization of Biped Walking Robot Using the Energy Shaping Method
Authors: Yazdi Ehsan Azadi , Alasty Aria
Published: September 2008

The biped walking robot demonstrates a stable limit cycle on shallow slopes. In previous researches, this passive gait was shown to be sensitive to ground slope and initial conditions. In this paper, we discuss the feedback stabilization of a biped robot by the “energy shaping” technique. Two designs are proposed to reduce the sensitivity of the biped walking robot to slope and initial conditions. In the first design, a moving mass actuator is located on each link of the robot. The actuators are used to shape the potential energy of the biped robot so that it tracks the potential energy of a known passive gait of a similar biped robot on a different slope. Although the method is applied to a simple kneeless planar biped, our results are completely generalizable and may be applied to general n-link bipeds. The second design uses a momentum wheel, which is placed on the hip of the robot to shape the energy of the biped. We use the controlled Lagrangian method to design the controller, and the simulation is carried out to show its performance. In the controlled Lagrangian method, either the total energy or the Lagrangian of the uncontrolled system is modified so that the Euler–Lagrange equations derived from this modified expression, called the controlled Lagrangian function, describe the closed loop equations of the system.
Numerical Simulation of Transient Multiphase Field During Hybrid Plasma-Laser Deposition Manufacturing
Authors: Kong Fanrong , Zhang Haiou , Wang Guilan
Published: September 2008

The hybrid plasma-laser deposition manufacturing (PLDM) process is developed based on the plasma deposition manufacturing (PDM) technology. PLDM belongs to the three-dimensional (3D) welding technology and involves the laser power as an augmented heat resource. Compared to PDM technology, the PLDM process has many advantages such as a higher power density, higher processing precision, refined microstructure, and improved mechanical performance of forming components. There exist complicated physical and metallurgical interaction mechanisms due to the combination of PLDM along with the rapid melting and solidification process. Moreover, the interaction between the laser and plasma arc also directly influences the forming quality and precision of the 3D metal components. Therefore, the proposed work is a preliminary attempt to study the transport phenomena in the PLDM process, in which the heat transfer, fluid flow, and molten powder depositing processes have been investigated in detail. The numerical study is performed by using a pressure-based finite volume difference technique after making appropriate modifications of the algorithm. The associated solid/liquid phase transformation process is involved by using an enthalpy-porosity method, and the level-set approach is introduced to track the evolution of weld surface of the deposition layer with powder feeding. An experimentally based hybrid heat input model is developed to involve the influence of the interaction of laser and arc plasma on the redistributed energy absorption by the material. Corresponding experiments of the PLDM process are performed using the same parameters as in the computations, showing a good qualitative agreement.
Development of Miniature Gripper Using Buckling Phenomenon of Long Column
Authors: Muramatsu N.
Published: September 2008

This paper developed the element technologies for commercialization of the miniature gripper which was considered in the previous paper. There, making use of buckling phenomenon of a long column was tried for the opening and closing mechanism of the miniature gripper. As a result, it was verified which was useful as the opening and closing mechanism of the fingers because it does not need a special mechanism for displacement enlargement, so unique, original and simple. The results obtained are as follows. (1) In the manufacturing of a multi-finger hand, the way for a blank cut from the elastic plate by wire-cut electrical discharge machine to be bent like a telescopic umbrella folded was devised. According to the way, not only will the finger with uneven division or variant be manufactured, but also could further miniaturization be made in similarity. (2) As for the adjustment technique of the gripping force, a positioning nut enabled translational displacement of a screw axis nut to be mechanically set. Consequently, the gripping force changes corresponding to the closing amount of the finger with 0 to maximum (solid contact). (3) In the application of this opening and closing mechanism, a pair of electric tweezers, which finger is automatically opened and closed approximately 5mm by one way rotation drive of a motor, was prototyped. Reciprocating translational displacement h0 of the hand center was realized by simple spherical cam mechanism comprising two small steel balls only with eccentricity each other which are in contact. Radii rc and rf of the steel balls of the prototype are 0.5mm, maximum lift h0 0.3mm and eccentricity 0.357mm.
The Evolution of Engineering and Technology View in P. R. China
Authors: Yi De-Gang , Zhao Xin-Li , Zhang Chao , Qi Zhong-Ying
Published: September 2008

In China, the national engineering and technology view has great influences on formulating and executing all kinds of engineering and technology developing strategies, policies and plans. The People’s Republic of China has been founded for more than 50 years. During this period Chinese science and technology, economy and society have gained remarkable changes, yet, there were many frustrations and backslides in the progress of development either. The evolution of engineering and technology view in P. R. China is characterized by “period”. This kind of “period” is correlated tightly with the political and economic conditions home and abroad, reflecting the ideologies of different period, and plays a very important role on the direction, scale and speed of the development of engineering and technology in each period. This paper divided the engineering and technology view into 6 periods from the foundation of P.R. China, analyzed them periodically according to cases and statistical data, and compared them. Finally, this paper carried on a further discussion and prediction on the engineering and technology view of the new century.
Simulation of Single and Multiple Impinging Jet Cooling and Comparison With Experimental Data
Authors: Gordeev S. , Heinzel V. , Slobodchuk V.
Published: September 2008

A number of turbulence models offered by the commercial code STAR-CD have been tested on the measurements published in the literature with the objective to compare their capabilities for the simulation of a flow and heat transfer in multiple impinging jets. Numerical predictions of the single jet and jet array air impinging heat transfer have been compared with experimental data. The comparison shows that only turbulence models with additional limiters for turbulence production in the stagnation zone are able to correctly predict the jet impingement heat transfer. Suga’s k-ε turbulence model with Yap-correction, k-ε RNG, V2F and SST turbulence models with different near wall modifications are in acceptable agreement with experiments. The deviations from the experimental data, which provide all the turbulence models, are analyzed.
Thermo-Hydrodynamic Analysis of Rough Journal Bearing
Authors: Bahzad A. , Abdel-Latif L. A. , El-Butch A. M. A.
Published: September 2008

Temperature rise in modern hydrodynamic bearings reaches so high values and none of the engineering surface is perfectly smooth, therefore, the results obtained from the solution of Reynolds equation alone doesn’t give a true picture of the bearing behavior. In this work, the Reynolds equation is solved iteratively with the energy and heat transfer equations using finite difference technique and some roughness patterns have been assumed for the inner surface of the bearing and the outer surface of the journal to assess their effects on the bearing performance characteristics. A comparison between the behavior of smooth and rough bearings has been conducted. It is found that the presence of roughness asperities has a considerable influence on the bearing performance characteristics. The most important conclusions are that, roughness effects are more pronounced at higher values of eccentricity ratio and the effect of transverse roughness is to increase the load capacity, whereas longitudinal roughness causes a decrease in load as compared to a smooth bearing.
A Decentralized Adaptive Neural Controller for Active Vehicle Suspension Systems
Authors: Chiou Kuo-Ching , Huang Shiuh-Jer
Published: September 2008

A decentralized adaptive neural controller (DANC) for active vehicle suspension systems using singular perturbation method is developed in this paper. In order to reduce the neural network (NN) weight’s number, the DANC is designed based on the decentralized single input single output (SISO) NN. The active suspension system SIMO characteristic is decoupled into two time-scale separated SISO systems via the singular perturbation technique for achieving a compromise between riding comfort and handing performance. The structure of this MIMO model-free controller is derived from the Lyapunov stability theory to monitor the system for tracking a user-defined reference model. The experimental results are discussed and compared with that of the passive suspension.
Experimental and Analytical Modeling of Phase Change Micropump
Authors: Saidi M. H. , Sadjadi B. , Safaei H. , Pirouzpanah S.
Published: September 2008

In this research a phase change micropump as a novel type of non-mechanical micropumps has been investigated. A one dimensional model has been developed to describe the pumping mechanism and assess the working characteristics of the micropump. Conservation of mass, momentum and energy have been employed to obtain an algebraic equation for the flow rate which depends on seven non-dimensional numbers. The governing equation has been solved to study the effect of various operating parameters on the micropump performance. To verify the analytical approach, an experimental set up has been constructed. The results show that the theoretical model is in reasonable agreement with the experimental investigations and can describe the pumping mechanism properly. This analytical approach can be used in the design and fabrication of more efficient micropumps.
Critical Penetration Depth for Nano/Micro Indentation Test to Determine Elastic-Plastic Film Properties Deposited on Hard Substrates
Authors: Chiba Norimasa , Ogasawara Nagahisa , Anghel Constantin Razvan , Chen Xi
Published: September 2008

The critical indentation depth to obtain proper elastic-plastic properties of thin film when the indentation tests are done on film/substrate system with sharp indenters is investigated. We focus on the characterization problem of soft film material, whose material properties are unknown, deposited on hard substrates. The critical depth is analyzed based on the finite element analysis (FEA) results. In order to extract the mechanical properties of the film from those of the film/substrate compound, we have to restrict the maximum penetration depth within a certain value. In this paper the relation between the load, P, and the depth, h, is analyzed in a power law relation, P = Chm, where the exponent m is a function of h. From extensive FEA results, we found that this exponent m starts to depart from 2 faster with increasing indenter apex angle and increasing hardening exponent of the film material. This means that the critical indentation depth decreases with increasing indenter apex angle and increasing hardening exponent. Based on this analysis, we propose a simple formula to evaluate the critical penetration depth h0, as a function of apex angle, θ, of the indenter: h0/d = 0.243cot θ, where d is the film thickness.
Experimental and Numerical Analyses of Mixed Mode Crack Initiation Angle
Authors: Al Bin Mousa Jafar , Merah Nesar , Eleiche Abdel-Salam , Arif Abul-Fazal
Published: September 2008

This paper presents a study for predicting crack initiation angle in the case of mixed mode fracture i.e., opening and sliding mode. Experimental and numerical analyses were carried out using photoelasticity and ANSYS finite element program, respectively. Polycarbonate specimens with a thickness of 3mm and different angles of inclinations namely 0° and 22.5° were considered in this analysis. Predicting the crack initiation angles is dependent on the value of stress in the vicinity of the crack tip. As a result, stress intensity factor is considered as the most significant parameter in this regard because it represents the stress level at the crack tip. In experimental analysis Schroedl and Smith method is used to calculate the pure opening mode stress intensity factor (KI) and Smith and Smith method for the mixed mode case (KI & KII). Then, SIF’s for straight and inclined crack are determined numerically using ANSYS. After that, the values of stress intensities are incorporated in minimum strain energy density criterion (S-Criterion) to find the crack’s angle of initiation.
Design of a Small Snow Gun for Limited Area Using CFD
Authors: Morency Franc¸ois , Halle´ Ste´phane , Dreger Slawomir , Jacques Daniel
Published: September 2008

Most of the ski resorts rely on man made snow for early opening of the slope in fall and improve snow cover all winter. This paper present tools and relation useful for conceptual and preliminary sizing of a fan snow gun. Once an initial shape is obtained, design is enhanced using numerical simulation of fluid flow by CFD commercial flow solver. Proposed simple relations are helpful but still need further improvement. As design get more complex and precise, CFD solutions become more attractive. With actual CFD tools, it should be possible to run 3D simulation of a fan snow gun.
Dynamics of Beams Using a Geometrically Exact Elastic Rod Approach
Authors: Alamo Fredy Coral , Weber Hans Ingo
Published: September 2008

The dynamics of a long slender beam, intrinsically straight, is addressed systematically for 3-D problems using the Cosserat rod theory. The model developed allows for bending, extension/compression and torsion, thus enabling the study of the dynamics of various types of elastic deformations. In this work a linear constitutive relation is used, also, the Bernoulli hypothesis is considered and the shear deformations are neglected. The fundamental problem when using any finite element (FE) formulation is the choice of the displacement functions. When using Cosserat rod theory this problem is handled using approximate solutions of the nonlinear equations of motion (in quasi-static sense). These nonlinear displacement functions are functions of generic nodal displacements and rotations. Based on the Lagrangian approach formed by the kinetic and strain energy expressions, the principle of virtual work is used to derive the nonlinear ordinary differential equations of motion that are solved numerically. As an application, a curved rod, formed by many straight elements is investigated numerically. When using the Cosserat rod approach, that take into account all the geometric nonlinearities in the rod, the higher accuracy of the dynamic responses is achieved by dividing the system into a few elements which is much less than the traditional FE methods, this is the main advantage when using this approach. Overall, the Cosserat model provides an accurate way of modelling long slender beams and simulation times are greatly reduced through this approach.
Analysis of the Sensitivity to Vibrations of an Optical Torquemeter
Authors: Bonfanti Marco , Lo Savio Fabio
Published: September 2008

The present paper reports an investigation into the effect of bending and torsional vibrations on the torsional angle measurements given by an optical laser torquemeter, already described at the ICEM12 (2004). The aim was to demonstrate that vibrations present do not have an excessive effect on the torque measurements, due to the intrinsic operating characteristics of the torquemeter. In order to render the device able to detect such vibrations, its structure and the signal acquisition and processing system were modified. High magnitude vibrations, found only rarely in a common rotating system, were then generated artificially.
Hybrid Driveline Concepts for Front and Rear Wheel Drive Cars
Authors: Ho¨hn Bernd-Robert , Pflaum Hermann , Tomic Daniel
Published: September 2008

At the Gear Research Center (FZG) of the Technical University of Munich concepts for hybrid drivelines are developed. The concepts discussed are based on automated manual transmission design. For the electric power flow the same gears are used in opposite torque flow direction compared to combustion engine power flow to enable good acceleration at low driving speed. In order to reduce fuel consumption the electric motor is also used for energy recuperation during deceleration of the vehicle. This energy may be stored by a battery or by double layer capacitors depending on the requirements (full/mild hybrid concept). In addition the driveline concept enables boosting during gear change of the automated manual transmission to reduce traction loss during gear change. Transmission concepts for front and rear wheel drive cars will be presented. Drivability is shown by simulations of the hybrid system behavior.
A Life Cycle Cost Analysis Approach for Selection of a Typical Heavy Usage Multistage Centrifugal Pump
Authors: Waghmode Laxman Y. , Birajdar Ravindra S. , Joshi Shridhar G.
Published: September 2008

It is well known that the pumps are the largest consumers of industrial motor energy and account for more than 25% of electricity consumption. The life cycle cost of a pump is the total lifetime cost associated with procurement, installation, operation, maintenance and its disposal. For majority of heavy usage pumps, the lifetime energy and/or maintenance cost will dominate the life cycle costs. Hence a greater understanding of all the cost components making up the total life cycle costs should provide an opportunity to achieve a substantial savings in energy and maintenance costs. This will further enable optimizing pumping system efficiency and improving pump and system reliability. Therefore in this context, the life cycle cost analysis of heavy usage pumps is quite important. This paper focuses on an application of a methodology of determining the life cycle cost of a typical heavy usage multistage centrifugal pump. In this case, all the cost components associated with the pump-set have been determined and classified under different categories. The data with regard to initial investment costs, operation costs, maintenance and repair costs and disposal costs for the pump considered for this case study was collected from the concerned pump manufacturer along with the unit cost of each component, quantity used and their weights. By applying the principles of reliability and maintainability engineering and using the data obtained from the design, manufacturing and maintenance departments, the component-wise values of MTBF (Mean Time Between Failures) and MTTR (Mean Time To Repair) were estimated. The results of the life cycle cost analysis of the specimen pump were compared with the life cycle costs of similar pumps reported in the literature. From this comparison of results, it can be concluded that, the initial cost of the pump is the only a fraction of the total life cycle cost. The operating cost of the pump dominates the life cycle costs especially in case of heavy usage pumps. The maintenance cost varies approximately from 0.6 to 2.5 times the initial cost of the pump. The life cycle cost of the pump varies approximately from 12 to 33 times the initial cost of the pump. The operation and maintenance cost is almost 92 to 97 per cent of the life cycle cost. The detailed analysis carried out in this paper is expected to provide guidelines to the pump manufactures/practicing engineers in selecting a heavy usage multistage centrifugal pump based on the total lifetime cost rather than only on initial price.
Near Optimal Grinding Process Design Using Neural Network and Real Coded Genetic Algorithm
Authors: Mukherjee Indrajit , Ray Pradip Kumar
Published: September 2008

A typical grinding process is an essential manufacturing operation and has been considered to be a precise and economical means of shaping the parts into the final products with required surface finish and high dimensional accuracy. The need to economically process hard and tough materials which can withstand varying stress conditions to ensure prolonged service life of parts has become a real challenge for researchers and practitioners. In this context, with the advance development and automation of grinding processes, use of appropriate modelling and optimization techniques has been continually emphasized. In view different types of end product and process requirements in grinding processes, optimization often becomes non-linear, multiple response constrained problem with multi-modal distribution of response quality characteristics. The objective of this study is to apply back propagation neural network modelling technique for prediction of a computer numeric-controlled (CNC) rough grinding process behaviour, and thereby determine overall near optimal process design using real coded genetic algorithm. The study proposes an integrated approach using back propagation neural network algorithm, composite desirability function, and real-coded genetic algorithm. The effectiveness and suitability of the approach is determined based on data analysis of a single-pass 6-cylinder engine liner CNC rough grinding (honing) operation in a leading automotive manufacturing unit in India.
A New Lumped-Mass Vehicle Ride Model Considering Body Flexibility
Authors: Goodarzi Avesta , Jalali Amir
Published: September 2008

Ride comfort is one of the most important criteria by which people judge the total quality of the car. Traditionally to investigate the vehicle ride comfort, some well-known classical lumped-mass models are used. In these models such as quarter car model, half car model and full vehicle model, body flexibility has been ignored and sprung mass (vehicle body) assumed to be rigid. This assumption can reduce the model accuracy, specially in the case of long vehicles such as vans, buses and trucks. To impose body flexibility in the ride analysis, recently some numerical FEM-based models have been introduced, but they are complex and non-parametric. In this paper the effects of body flexibility on the vehicle vibration behavior has been studied based on an analytical approach. For this purpose, a new simple and parametric lumped-mass 8 DOF model has been developed. Comparison of the results of natural frequency analysis and forced vibration analysis for this model with the corresponding results of so called “rigid model” or “classic model” is very informative. As the results are shown, body flexibility strongly influenced on the acceleration and displacement responses of the vehicle so that it is necessary to considering this term at the early stages of the vehicle design.
Transition to Turbulence in a Czochralski Convective Flow
Authors: Rahal Samir , Azuma Hisao
Published: September 2008

The aim of this study is to recognize the flow states and the transition mechanisms between them in a simulated Czochralski convective system. We considered the influence of the crystal rotation effects (up to Reynolds number, Re = 3.9 × 103) and the buoyancy (up to Rayleigh number, Ra = 7.2 × 107) on the flow. Using velocity fields, obtained by an ultrasonic method, the corresponding 2D Fourier spectra and a correlation function; steady, quasi-periodic and turbulent states were recognized as the Reynolds number was increased. The orthogonal decomposition method was applied to these velocity fields. The numbers of modes involved in the dynamics of turbulent states were calculated. From these results, we have concluded that the rotation effects tend to stabilize the flow, and the thermal gradients play a destabilizing role.
Determination of Velocity Profiles of Sand Particles in Jetting Bed
Authors: Ounnar A. , Arrar J. , Bentahar F.
Published: September 2008

In the present study, the hydrodynamic behaviour of the submerging jet from nozzle in particular medium by determining the velocity profiles is presented. The experimental part is carried out on a 250 mm column filled with sand particles of 230 μm mean diameter and 2576 kg/m3 density. The central vertically ascending jet air is obtained from a nozzle with 15 mm diameter. Three different nozzles with lengths of 80 mm, 40 mm and 0 mm from above the distribution grid were used. The present work shows that the jet fundamental properties and the self similarity of the reduced velocity profiles remain constant in the process and its use in a solid particles bed favours fluidization phenomena. The self similarity of the reduced velocity profiles is thus an intrinsic property in the steady state flow of the jets in a particular medium, whatever the longitudinal axis, the length of the nozzle, the initial jet velocity and the bed state (aerated or fluidized).
Experimental Identification of a Motorcycle Rider 3D Movements on a Running Vehicle
Authors: Bocciolone M. , Cheli F. , Leo E. , Pezzola M.
Published: September 2008

The aim of the research is to identify the movements of a race motorcycle rider while running on a race track. It is well known how the inertial characteristics of human body are comparable to the motorcycle ones. It is necessary to understand the body-vehicle interactions to describe the dynamical behaviour of the complete system. A numerical model of pilot-vehicle system, in a multi body logic, is being developed, using the results of this research. The tested motorcycle is equipped by a fixed original measurements system, characterised by five cable-extension position transducer (voltage divider type). The pilot’s back is equipped by a rigid ergal staff, constrained by a multi cross belts system, on which two target points are placed, with pre defined distance. These targets are pointed by the five sensors. Through the use of a non linear numerical model it is possible to identify the translational and the cardanic rotational 3D movements of the rider body. To proceed with the procedure validation and calibration, an anthropomorphic arm robot was used. The targets staff was constrained on the end effector, the sensors system was ground fixed and incremental displacements and rotations were programmed. Some results finally obtained in a first experimental session are reported.
Wire-Driven Pneumatic Actuation of a New 6-DOF Haptic Master
Authors: Ferraresi Carlo , Carello Massimiliana , Pescarmona Francesco , Grassi Roberto
Published: September 2008

The paper presents the results of a work carried out by the Department of Mechanics of Politecnico di Torino, concerning the study and development of a six degrees of freedom force reflecting master structure for teleoperation (haptic device) to be controlled by an operator. The latter imposes the six-dimensional linear and angular displacement of a handle, controlling a remote slave robot or interacting with virtual reality. On the other hand, the operator receives a force feedback related to the environment in which the slave robot or virtual device operates. Since the actuators must be force controlled in order to generate a resultant corresponding to the desired wrench, pneumatic actuation has been chosen because it is particularly suitable to the application and quite economical.
Oil Whip and Unstable Whirling in Anisotropic Rotors on Lubricated Bearings
Authors: Genta Giancarlo , Amati Nicola
Published: September 2008

The dynamics of rotors running on lubricated bearings is complex. While the linearized analysis allows to study the stability in the small and phenomena like oil whirl and oil whip, more complex behaviour, that may include chaotic motion, requires a fully nonlinear analysis. Since lubricated bearings behave like anisotropic supports, complex whirling pattern can be expected when the rotor is anisotropic. The aim of the present paper is to investigate to what extent the anisotropy of the rotor affects its dynamic behaviour. In particular, the interactions between the instability ranges due to rotating anisotropy and to oil whip are searched. The rotor models are built using DYNROT FEM code to build the basic rotor model and to obtain linearized solutions. The linear model of the rotor is then mated to nonlinerar bearing models and integrated numerically in time. Time domain results allow to draw some general conclusions applicable to simplified models as well as to real-world rotors.