bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of the forces in different regions during hobbing and their effect on distortion
Authors: Kohlhoff T. 
Published: June 2009

AbstractBy hobbing, distortion potential is induced into the workpiece, which leads to distortion of the gear teeth in the subsequent heat treatment process. To investigate the generation of distortion by hobbing precisely, the analysing methods have to be adapted to the process. To be able to choose adequate methods, preliminary investigations are accomplished to analyse the dimension and shape of the machining induced distortion. Since the hobbing process is divided into three regions with different process conditions, the influence of these differences on the distortion has to be considered. Therefore a variation of the facewidth is performed and the occurring forces are measured to analyse the process conditions. The results are used to derive suitable research and analysing methods.
Influence of clamping conditions on distortion during heating of bearing rings
Authors: Surm H. , Hoffmann F. 
Published: June 2009

AbstractIn experimental examinations, the change in roundness deviations of bearing rings due to quench hardening was exclusively determined by the used clamping technique during turning, which led to a characteristic manufacturing residual stress state. In the present paper, the influence of manufacturing residuals stresses on distortion was studied by means of finite element analysis. Therefore, a typical residual stress distribution in a bearing ring after machining was generated in a first simulation procedure. The calculated residual stress profiles were in good agreement with XRD‐measurements. In a second step, a homogeneous heating up to transformation temperature Ac1was simulated. Stress relief can be attributed to local plastic deformation if the local equivalent stress approached the temperature dependent yield strength. Rearrangement of stresses in the complete ring can be correlated to temperature dependent change in roundness deviation. From the comparison of the simulated roundness deviation with experimental results, it could be concluded that plastic deformation by stress relief during heating could be a significant distortion mechanism regarding the roundness deviation of bearing rings.
In‐process measurement system based on laser triangulation during heat treatment
Authors: Gafsi H. , Goch G. 
Published: June 2009

AbstractThis paper presents the calibration and the use of a laser triangulation system for non‐contact measurements of workpiece geometry changes during heat treatment. The system was developed within the scope of the Collaborative Research Centre SFB570 of the Deutsche Forschungsgemeinschaft to provide geometrical information obtained in hot environments (temperatures up to 900 °C) for the verification of heat treatment simulations. Due to its in‐process‐measurement capability, this system also enables the closed‐loop control of distortion compensation. It will be applied in a furnace specially designed for heating steel rings symmetrically or asymmetrically.The developed calibration routine, which includes the application of gauge rings with different diameters, is described and the obtained uncertainties are discussed. Measurement results of an austenitic cylindrical ring are compared with reference dilatometry data to validate the calibration routine.
The heat treatment of steel – a mathematical control problem
Authors: Hömberg D. , Kern D. 
Published: June 2009

AbstractThe goal of this paper is to show how the heat treatment of steel can be modelled in terms of a mathematical optimal control problem. The approach is applied to laser surface hardening and the cooling of a steel slab including mechanical effects. Finally, it is shown how the results can be utilized in industrial practice by a coupling with machine‐based control.
Similarities and differences in heat treatment simulation of aluminium alloys and steels
Authors: Kessler O. , Reich M. 
Published: June 2009

AbstractAluminium alloys are nowadays applied in light weight constructions of many areas, e.g. transportation. Several manufacturing technologies are used in production chains of aluminium components. For improvements in strength heat treatments are carried out with aluminium alloys (precipitation hardening) as well as with steels (martensitic hardening). Besides the intended microstructures and properties, dimension and shape changes as well as residual stresses of the components are heat treatment results. Simulation tools based on the finite element method help to predict heat treatment results without extensive tests. Among other inputs one necessary pre‐requisite is a detailed database for the material. This database must contain the fundamental material parameters like heat conductivity, specific heat capacity, density, thermal expansion coefficient, modulus of elasticity, Poisson´s ratio and strain hardening, all of them depending on phases and temperature. Further, models for phase transformations and precipitation processes must be implemented. For steels heat treatment simulations of complex components are already possible. Some heat treatment parameters and material parameters of steels and aluminium alloys differ significantly. Aluminium alloys usually exhibit lower solution annealing temperatures, higher cooling rates, higher heat conductivity, higher thermal expansion coefficient, lower modulus of elasticity and lower strength. Further, the material database is partially missing for aluminium alloys, especially precipitation models. Exemplarily heat treatment simulations focused on the material parameters of aluminium alloys will be presented and similarities as well as differences compared to steels will be discussed.
Simulation of the distortion manipulation of gear wheel teeth by thermal pre‐stressing
Authors: Pretorius T. , Vollertsen F. 
Published: June 2009

AbstractAn additional process step in the production process chain of steel components, the thermal induced pre‐stressing, has been developed. This new process step enables the manipulation of the distortion potential of the components before it is released in the hardening process at the end of the process chain. In order to predict the final distortion of the component in dependence on the process parameters of the thermal pre‐stressing a simulation model has been developed, which also includes the final heat treatment (hardening process). The model accounts for the stress and deformation due to the generation of thermal strain as well as those due to phase transformations. A first implementation was done using the geometry of an idealized gear wheel tooth (finger sample). After optimization, with special focus on the calculation time, the application for realistic gear wheel teeth has been implemented.
Deep brain stimulation and cognitive functions in Parkinson's disease: A three‐year controlled study
Authors: Zangaglia Roberta , Pacchetti Claudio , Pasotti Chiara , Mancini Francesca , Servello Domenico , Sinforiani Elena , Cristina Silvano , Sassi Marco , Nappi Giuseppe 
Published: June 2009

AbstractThere is debate over the cognitive and behavioral effects of deep brain stimulation (DBS) of the subthalamic nucleus (STN) in advanced Parkinson's disease (PD). To evaluate these effects, we performed a prospective, naturalistic controlled, 3‐year follow‐up study. A total of 65 PD patients were enrolled, of whom 32 underwent STN‐DBS (PD‐DBS) and 33, even though eligible for this treatment, declined surgery and chose other therapeutic procedures (PD‐control). Motor and neuropsychological functions were assessed in all the subjects at baseline (T0) and 36 months (T36). The PD‐DBS patients were also evaluated at 1, 6, 12, and 24 months after surgery (T1, T6, T12, and T24). At T1, compared with T0, the PD‐DBS patients recorded worse logical executive function task and verbal fluency (FAS) scores, whereas their performance of memory tasks remained stable. At T12, their cognitive profile had returned within the pre‐DBS range, thereafter remaining stable until T36. FAS scores at T36 were significantly worse in the PD‐DBS compared with the PD‐control patients. This is the first long‐term naturalistic controlled study of cognitive functions in PD patients submitted to STN‐DBS. Our results confirm previous reports of a worsening of verbal fluency after DBS, but show that STN‐DBS seems to be relatively safe from a cognitive standpoint, as the short‐term worsening of frontal‐executive functions was found to be transient. © 2009 Movement Disorder Society
Essential tremor in Parkinson's disease kindreds from a population of similar genetic background
Authors: Spanaki Cleanthe , Plaitakis Andreas 
Published: June 2009

AbstractTo investigate the possible association between essential tremor (ET) and Parkinson's disease (PD) we conducted a prospective clinical and epidemiological study in a population of similar genetic background. The first‐degree relatives of 303 PD probands and 249 controls from Crete were evaluated for the presence of ET. In addition, the possible co‐occurrence of ET and PD in the same family or in the same individual was investigated. Results showed that ET was present in the relatives of PD patients more often than in those of controls (OR:3.64, P < 0.001). The risk was even greater (OR: 4.48) when the affected proband had tremor‐dominant or mixed PD. Female relatives and siblings of PD patients were more likely to have ET than male relatives and parents of PD patients (OR: 4.36 v/s 2.89 and 4.49 v/s 2.74, respectively). Twelve subjects had both ET and PD phenotypes. While this may have occurred by chance, a number of families were identified in which ET and PD were coinherited through the same parental line. Hence, in certain families ET and PD are genetically related probably sharing common hereditary predisposition. © 2009 Movement Disorder Society
Is impact of fatigue an independent factor associated with physical activity in patients with idiopathic Parkinson's disease?
Authors: Elbers Roy , van Wegen Erwin E.H. , Rochester Lynn , Hetherington Victoria , Nieuwboer Alice , Willems Anne‐Marie , Jones Diana , Kwakkel Gert 
Published: June 2009

AbstractTo investigate the longitudinal association between fatigue and physical activity in Parkinson's disease (PD) and determine whether this association is distorted by potential confounders. Data from baseline, 3, 6, and 12 week assessments in a single blind randomized clinical trial with cross‐over design were used (N = 153). The Multidimensional Fatigue Inventory (MFI) was used to assess fatigue and an activity monitor to measure amount of physical activity (defined as % dynamic activity during each monitoring session). Time‐independent and time‐dependent factors were investigated for their possible univariate association with dynamic activity. Random coefficient analysis was applied. Candidate confounders were successively added to the longitudinal association model to determine if the association between dynamic activity and fatigue was distorted. A proportional change beyond 15% was considered to be significant. Fatigue was significantly associated with physical activity (β = −0.099, SE = 0.032, P = 0.002). This association was not significantly distorted by type of intervention, age, gender, social support, disease duration, disease severity, motor impairment, cognition, anxiety, or medication intake. Depression caused proportional change of 22.2% in the regression coefficient of MFI. After controlling for depression, a significant association between MFI and dynamic activity remained (β = −0.121, SE = 0.036, P = 0.000). The association found between fatigue and dynamic activity suggests that patients who experience higher levels of fatigue are less physically active. However, the total explained variance of dynamic activity by fatigue alone was small, suggesting that fatigue is only a minor factor in the complex of behavioral aspects that affect the amount of physical activity in patients with PD. © 2009 Movement Disorder Society
‘Extra information a bit further down the line’: Rheumatoid arthritis patients' perceptions of developing educational material about the cardiovascular disease risk
Authors: John Holly , Hale Elizabeth D. , Treharne Gareth J. , Carroll Douglas , Kitas George D. 
Published: June 2009

AbstractObjective: There are no patient education programmes addressing the increased risk of cardiovascular disease (CVD) associated with rheumatoid arthritis (RA). This is the second in a pair of studies exploring stakeholder perceptions of developing such educational material. Healthcare professionals' perceptions were explored in the first study; here, we explore the perceptions of people with RA.Methods: Semi‐structured interviews were held individually with 18 people with RA, purposively sampled to include participants with no co‐morbid history of CVD, those with CVD risk factors and those who had experienced a CVD event. The interview transcripts were analysed using interpretative phenomenological analysis.Results: Four superordinate themes were identified: experiences of living with RA; reactions to learning about co‐morbid CVD; implementing lifestyle changes; and expectations of education. Participants found being diagnosed with RA a devastating experience and were mostly unaware of their increased risk of CVD co‐morbidity. They explained how information about CVD would be overwhelming and irrelevant at diagnosis, but they would have coped with ‘extra information a bit further down the line’.Conclusion: There is a need to develop educational material or programmes. Their design must consider factors which facilitate lifestyle change, such as motivation or receiving personalized advice, and factors that inhibit change, such as depression or fatalism. Emphasizing the positive effects that some CVD lifestyle changes may have on RA symptom control may be particularly persuasive. Group education would be a popular format. These findings can be directly translated into clinical practice. Copyright © 2009 John Wiley & Sons, Ltd.
Changes in hemiplegic grasp following distributed repetitive intervention: a case series
Authors: Conti Gerry E. , Schepens Stacey L. 
Published: June 2009

AbstractThe purpose of this pilot study was to investigate the efficacy of a distributed model of repetitive and focused intervention on grasp force, and clinical and functional hand measures in persons with chronic hemiplegia and limited hand recovery from self‐reported stroke.A case series design was used. Focused repetitive unilateral and bilateral interventions were provided in a distributed manner (three times a week for 6 weeks) to three persons with upper limb hemiplegia of more than 1 year. Data from instrumented grasp force, and clinical and functional measures were obtained at weeks 0, 3, 6 and 9.Each participant improved in at least one measure of grasp force, as well as in clinical skill and function. All participants improved in the quality of handwriting. Improved outcomes remained above baseline levels following 3 weeks of non‐intervention. The findings are compatible with current evidence of adaptive cortical plasticity following increased repetition. The findings show that, for these three persons, distributed repetitive practice was sufficient to effect change.Localization by cerebral area affected is not possible, nor is it possible to parse the effectiveness of any component of the intervention.A larger group study is warranted to determine whether similar results may be found for other persons with chronic hemiplegia. Future studies should incorporate kinematic handwriting analysis and a greater range of functional tasks. Copyright © 2009 John Wiley & Sons, Ltd.
Behind closed doors: systematic analysis of breast cancer consultation communication and predictors of satisfaction with communication
Authors: Hack Thomas F. , Pickles Tom , Ruether J. Dean , Weir Lorna , Bultz Barry D. , Degner Lesley F. 
Published: June 2009

AbstractObjective: The purpose of this investigation was to explicate the content of primary adjuvant treatment consultations in breast oncology and examine the predictive relationships between patient and oncologist consultation factors and patient satisfaction with communication.Methods: The recorded consultations of 172 newly diagnosed breast cancer patients from four Canadian cancer centers were randomly drawn from a larger subset of 481 recordings and examined by three coders using the Medical Interaction Process System (MIPS); a system that categorizes the content and mode of each distinct utterance. The MIPS findings, independent observer ratings of patient and oncologist affective behavior, and derived consultation ratios of patient centeredness, patient directedness, and psychosocial focus, were used to predict patient satisfaction with communication post‐consultation and at 12‐weeks post‐consultation.Results: Biomedical content categories were predominant in the consultations, accounting for 88% of all utterances, followed by administrative (6%) and psychosocial (6%) utterances. Post‐consultation satisfaction with communication was significantly higher for older patients, those with smaller primary tumors and those with longer consultations. Smaller tumor, lack of patient assertiveness during the treatment consultation and having the consultation with a radiation rather than medical oncologist were significantly predictive of greater satisfaction at 12‐weeks post‐consultation.Conclusions: Adjuvant treatment consultations are characterized by a high degree of information‐giving by the physician, a predominance of biomedical discussion and relatively minimal time addressing patients' psychosocial concerns. Controlled trials are needed to further identify and address the contextual features of these consultations that enhance patient satisfaction. Copyright © 2009 John Wiley & Sons, Ltd.
The impact of different definitions and reference groups on the prevalence of cognitive impairment: a study in postmenopausal breast cancer patients before the start of adjuvant systemic therapy
Authors: Schilder Christina M. , Seynaeve Caroline , Linn Sabine C. , Boogerd Willem , Gundy Chad M. , Beex Louk V. , van Dam Frits S. , Schagen Sanne B. 
Published: June 2009

AbstractObjective: Several prospective studies into the effects of adjuvant systemic therapy on cognitive functioning suggest that a proportion of breast cancer patients show cognitive deficits already before the start of systemic therapy. Owing to, among others, methodological inconsistency, studies report different rates of this pre‐treatment cognitive impairment. We examined the impact of four different criteria of cognitive impairment and two types of reference groups (a study‐specific healthy reference group versus published normative data) on the prevalence of cognitive impairment.Methods: Two hundred and five postmenopausal breast cancer patients underwent a battery of neuropsychological tests before the start of endocrine therapy, 124 healthy subjects underwent the same tests. Proportions of cognitive impaired patients were calculated for each of four criteria for cognitive impairment, using (1) study‐specific healthy controls and (2) published norms of healthy controls as reference groups.Results: The prevalence of cognitive impairment varied greatly with the strictness of the criterion, as expected, but also was dependent on the reference group used. Cognitive impairment, relative to published norms, ranged from 1% for the strictest to 36.6% for the less strict criterion, cognitive impairment relative to study‐specific healthy controls, ranged from 13.7 to 45.4% for the same criteria.Conclusion: This study highlights contrasting proportions of cognitive impairment by using different criteria for cognitive impairment and different reference groups. (Dis)advantages of the methods using a criterion for cognitive impairment, and of the use of published norms versus a study‐specific reference group are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
InAlN‐barrier HFETs with GaN and InGaN channels
Authors: Liberis J. , Matulionienė I. , Matulionis A. , Šermukšnis E. , Xie J. , Leach J. H. , Morkoç H. 
Published: June 2009

AbstractAdvantages and drawbacks of InN‐containing GaN‐based heterostructure field‐effect transistors (HFETs) are reviewed. The main attention is paid to fundamental processes and experimental observations associated with hot‐electron transport in two‐dimensional electron gas (2DEG) channels subjected to high electric fields. Complementary information is obtained from fluctuations. When interface roughness and alloy scattering are minimized, an important transport limitation originates from additional scattering of hot electrons by non‐equilibrium longitudinal optical (LO) phonons (hot phonons) governed by the hot‐phonon temperature and the hot‐phonon decay into acoustic phonons. The ultrafast decay is observed for high supplied power where the hot‐phonon lifetime of ∼60 fs is found. The optimal 2DEG density for the fastest decay of hot phonons is estimated and associated with LO‐phonon–plasmon resonance. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
SiC avalanche photodiodes and photomultipliers for ultraviolet and solar‐blind light detection
Authors: Vert Alexey , Soloviev Stanislav , Sandvik Peter 
Published: June 2009

AbstractSilicon carbide (SiC) is known for its large bandgap and suitability to make direct conversion ultraviolet photo‐detectors. These devices show appreciable quantum efficiencies in the 240–350 nm wavelength range in combination with low dark currents. This paper presents recent study results of 4H‐SiC avalanche photodiodes and solid‐state photomultiplier arrays. The material quality is an issue that has to be addressed. It has been found that a large number of defects in the device structure could substantially affect the single‐photon avalanche diodes yield, while regular photodiodes yield is more immune to the presence of defects. Some single‐photon avalanche photodiodes have demonstrated low dark count rates in the range of several kHz and single photon detection efficiency of more than 10% at 266 nm in the solar‐blind wavelengths range. A novel SiC‐based 12‐pixel photomultiplier array was demonstrated for the first time. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Receptor binding activities of Chlorella on cysteinyl leukotriene CysLT, glutamate AMPA, ion channels, purinergic P2Y, tachykinin NK2receptors and adenosine transporter
Authors: Cheng Fong‐Chi , Feng Jin‐Jye , Chen Kuo‐Hsin , Imanishi Hideyo , Fujishima Masaki , Takekoshi Hideo , Naoki Yo , Shimoda Minoru 
Published: June 2009

AbstractA Chlorella powder was tested in a total of 129in vitroreceptor binding assay systems. The results showed a potent inhibition of this powder on cysteinyl leukotriene CysLT2, and glutamate AMPA in a dose‐concentration manner with IC50mean ± SEM values of 20 ± 4.5 µg/mL and 44 ± 14 µg/mL, respectively. Other moderate and weak activities reflected in competitive binding experiments were seen versus adenosine transporter; calcium channel L‐type, benzothiazepine; gabapentin; kainate, NMDA‐glycine; inositol trisphosphate IP3; cysteinyl CysLT1, LTB4; purinergic P2Y; tachykinin NK2; serotonin 5‐HT2Band prostanoid, thromboxane A2. Together, the results suggest that the various inhibitory effects of Chlorella powder in these receptor binding assays could reflect its actions in modulating Ca2+‐dependent signal related targets and might be relevant to the mechanisms of its biological effects. These results reveal important potential biochemical activities that might be exploited for the prevention or treatment of several pathologies. From these results, the possible therapeutic usage of the product is discussed. Copyright © 2009 John Wiley & Sons, Ltd.