bluuebunny/crossref_metadata_2025 huggingface dataset:
Aggressiveness of Cancer Care Near the End of Life: Is It a Quality-of-Care Issue?
Authors: Earle Craig C. , Landrum Mary Beth , Souza Jeffrey M. , Neville Bridget A. , Weeks Jane C. , Ayanian John Z.
Published: August 2008

The purpose of this article is to review the literature and update analyses pertaining to the aggressiveness of cancer care near the end of life. Specifically, we will discuss trends and factors responsible for chemotherapy overuse very near death and underutilization of hospice services. Whether the concept of overly aggressive treatment represents a quality-of-care issue that is acceptable to all involved stakeholders is an open question.
Evaluation of End-of-Life Cancer Care From the Perspective of Bereaved Family Members: The Japanese Experience
Authors: Miyashita Mitsunori , Morita Tatsuya , Hirai Kei
Published: August 2008

Surveying bereaved family members could enhance the quality of end-of-life cancer care in inpatient palliative care units (PCUs). We systematically reviewed nationwide postbereavement studies of PCUs in Japan and attempts to develop measures for evaluating end-of-life care from the perspective of bereaved family members. The Care Evaluation Scale (CES) for evaluating the structures and processes of care, and the Good Death Inventory (GDI) for evaluating the outcomes of care were considered suitable methods. We applied a shortened version of the CES to three nationwide surveys from 2002 to 2007. We developed the CES as an instrument to measure the structures and processes of care and the GDI as an outcomes measure for end-of-life cancer care from the perspective of bereaved family members. We conducted three nationwide surveys in 1997, 2001, and 2007 (n = 850, 853, and 5,301, respectively). Although six of the 10 areas of the CES showed significant improvements between the two time points investigated, we identified considerable potential for further progress. Feedback from surveys of bereaved family members might help to improve the quality of end-of-life cancer care in inpatient PCUs. However, the effectiveness of feedback procedures remains to be confirmed. Furthermore, there is a need to extend the ongoing evaluation process to home care hospices and general hospitals, including cancer centers, identify the limitations of end-of-life care in all settings, and develop strategies to overcome them.
Evidence-Based Standards for Cancer Pain Management
Authors: Dy Sydney M. , Asch Steven M. , Naeim Arash , Sanati Homayoon , Walling Anne , Lorenz Karl A.
Published: August 2008

High-quality management of cancer pain depends on evidence-based standards for screening, assessment, treatment, and follow-up for general cancer pain and specific pain syndromes. We developed a set of standards through an iterative process of structured literature review and development and refinement of topic areas and standards and subjected recommendations to rating by a multidisciplinary expert panel. Providers should routinely screen for the presence or absence and intensity of pain and should perform descriptive pain assessment for patients with a positive screen, including assessment for likely etiology and functional impairment. For treatment, providers should provide pain education, offer breakthrough opioids in patients receiving long-acting formulations, offer bowel regimens in patients receiving opioids chronically, and ensure continuity of opioid doses across health care settings. Providers should also follow up on patients after treatment for pain. For metastatic bone pain, providers should offer single-fraction radiotherapy as an option when offering radiation, unless there is a contraindication. When spinal cord compression is suspected, providers should treat with corticosteroids and evaluate with whole-spine magnetic resonance imaging scan or myelography as soon as possible but within 24 hours. Providers should initiate definitive treatment (radiotherapy or surgical decompression) within 24 hours for diagnosed cord compression and should follow up on patients after treatment. These standards provide an initial framework for high-quality evidence-based management of general cancer pain and pain syndromes.
Evidence-Based Recommendations for Cancer Fatigue, Anorexia, Depression, and Dyspnea
Authors: Dy Sydney M. , Lorenz Karl A. , Naeim Arash , Sanati Homayoon , Walling Anne , Asch Steven M.
Published: August 2008

Purpose

The experience of patients with cancer often involves symptoms of fatigue, anorexia, depression, and dyspnea.

Methods

We developed a set of standards through an iterative process of structured literature review and development and refinement of topic areas and standards and subjected recommendations to rating by a multidisciplinary expert panel.

Results

For fatigue, providers should screen patients at the initial visit, for newly identified advanced cancer, and at chemotherapy visits; assess for depression and insomnia in newly identified fatigue; and follow up after treatment for fatigue or a secondary cause. For anorexia, providers should screen at the initial visit for cancer affecting the oropharynx or gastrointestinal tract or advanced cancer, evaluate for associated symptoms, treat underlying causes, provide nutritional counseling for patients undergoing treatment that may affect nutritional intake, and follow up patients given appetite stimulants. For depression, providers should screen newly diagnosed patients, those started on chemotherapy or radiotherapy, those with newly identified advanced disease, and those expressing a desire for hastened death; document a treatment plan in diagnosed patients; and follow up response after treatment. For general dyspnea, providers should evaluate for causes of new or worsening dyspnea, treat or symptomatically manage underlying causes, follow up to evaluate treatment effectiveness, and offer opioids in advanced cancer when other treatments are unsuccessful. For dyspnea and malignant pleural effusions, providers should offer thoracentesis, follow up after thoracentesis, and offer pleurodesis or a drainage procedure for patients with reaccumulation and dyspnea.

Conclusion

These standards provide a framework for evidence-based screening, assessment, treatment, and follow-up for cancer-associated symptoms.
Evidence-Based Recommendations for Cancer Nausea and Vomiting
Authors: Naeim Arash , Dy Sydney M. , Lorenz Karl A. , Sanati Homayoon , Walling Anne , Asch Steven M.
Published: August 2008

The experience of patients living with cancer and being treated with chemotherapy often includes the symptoms of nausea and vomiting. To provide a framework for high-quality management of these symptoms, we developed a set of key targeted evidence-based standards through an iterative process of targeted systematic review, development, and refinement of topic areas and standards and consensus ratings by a multidisciplinary expert panel as part of the RAND Cancer Quality–Assessing Symptoms Side Effects and Indicators of Supportive Treatment Project. For nausea and vomiting, key clinical standards included screening at the initial outpatient and inpatient visit, prophylaxis for acute and delayed emesis in patients receiving moderate to highly emetic chemotherapy, and follow-up after treatment for nausea and vomiting symptoms. In addition, patients with cancer and small bowel obstruction were examined as a special subset of patients who present with nausea and vomiting. The standards presented here for preventing and managing nausea and vomiting in cancer care should be incorporated into care pathways and should become the expectation rather than the exception.
Measuring Supportive Care in Medical Oncology Practice: Lessons Learned From the Quality Oncology Practice Initiative
Authors: McNiff Kristen K. , Neuss Michael N. , Jacobson Joseph O. , Eisenberg Peter D. , Kadlubek Pamela , Simone Joseph V.
Published: August 2008

We provide a brief review of the use of quality measures to assess supportive care in the medical oncology office. Specifically, we discuss the development and implementation of supportive care measures in the Quality Oncology Practice Initiative (QOPI), a voluntary quality measurement and improvement program of the American Society of Clinical Oncology. QOPI has demonstrated that medical oncologists voluntarily engage in self-assessment and often select measures related to supportive care for measurement and improvement. Results to date have demonstrated that there is room for improvement in this domain. Because supportive care measures appropriate for use through structured chart review in the outpatient oncology setting are not generally available in the published literature, measures have been developed and tested through the program. Additional measures are in development for implementation in QOPI in 2008.
Role of Hormones, Genes, and Environment in Human Cryptorchidism
Authors: Foresta Carlo , Zuccarello Daniela , Garolla Andrea , Ferlin Alberto
Published: August 2008

Cryptorchidism is the most frequent congenital birth defect in male children (2–4% in full-term male births), and it has the potential to impact the health of the human male. In fact, although it is often considered a mild malformation, it represents the best-characterized risk factor for reduced fertility and testicular cancer. Furthermore, some reports have highlighted a significant increase in the prevalence of cryptorchidism over the last few decades. Etiology of cryptorchidism remains for the most part unknown, and cryptorchidism itself might be considered a complex disease. Major regulators of testicular descent from intraabdominal location into the bottom of the scrotum are the Leydig-cell-derived hormones testosterone and insulin-like factor 3. Research on possible genetic causes of cryptorchidism has increased recently. Abundant animal evidence supports a genetic cause, whereas the genetic contribution to human cryptorchidism is being elucidated only recently. Mutations in the gene for insulin-like factor 3 and its receptor and in the androgen receptor gene have been recognized as causes of cryptorchidism in some cases, but some chromosomal alterations, above all the Klinefelter syndrome, are also frequently involved. Environmental factors acting as endocrine disruptors of testicular descent might also contribute to the etiology of cryptorchidism and its increased incidence in recent years. Furthermore, polymorphisms in different genes have recently been investigated as contributing risk factors for cryptorchidism, alone or by influencing susceptibility to endocrine disruptors. Obviously, the interaction of environmental and genetic factors is fundamental, and many aspects have been clarified only recently.
Resolving the Conundrum of Islet Transplantation by Linking Metabolic Dysregulation, Inflammation, and Immune Regulation
Authors: Huang Xiaolun , Moore Daniel J. , Ketchum Robert J. , Nunemaker Craig S. , Kovatchev Boris , McCall Anthony L. , Brayman Kenneth L.
Published: August 2008

Although type 1 diabetes cannot be prevented or reversed, replacement of insulin production by transplantation of the pancreas or pancreatic islets represents a definitive solution. At present, transplantation can restore euglycemia, but this restoration is short-lived, requires islets from multiple donors, and necessitates lifelong immunosuppression. An emerging paradigm in transplantation and autoimmunity indicates that systemic inflammation contributes to tissue injury while disrupting immune tolerance. We identify multiple barriers to successful islet transplantation, each of which either contributes to the inflammatory state or is augmented by it. To optimize islet transplantation for diabetes reversal, we suggest that targeting these interacting barriers and the accompanying inflammation may represent an improved approach to achieve successful clinical islet transplantation by enhancing islet survival, regeneration or neogenesis potential, and tolerance induction. Overall, we consider the proinflammatory effects of important technical, immunological, and metabolic barriers including: 1) islet isolation and transplantation, including selection of implantation site; 2) recurrent autoimmunity, alloimmune rejection, and unique features of the autoimmune-prone immune system; and 3) the deranged metabolism of the islet transplant recipient. Consideration of these themes reveals that each is interrelated to and exacerbated by the other and that this connection is mediated by a systemic inflammatory state. This inflammatory state may form the central barrier to successful islet transplantation. Overall, there remains substantial promise in islet transplantation with several avenues of ongoing promising research. This review focuses on interactions between the technical, immunological, and metabolic barriers that must be overcome to optimize the success of this important therapeutic approach.
Dlx3 is a crucial regulator of hair follicle differentiation and cycling
Authors: Hwang Joonsung , Mehrani Taraneh , Millar Sarah E. , Morasso Maria I.
Published: August 2008

Dlx homeobox transcription factors regulate epidermal, neural and osteogenic cellular differentiation. Here, we demonstrate the central role of Dlx3 as a crucial transcriptional regulator of hair formation and regeneration. The selective ablation of Dlx3 in the epidermis results in complete alopecia owing to failure of the hair shaft and inner root sheath to form, which is caused by the abnormal differentiation of the cortex. Significantly, we elucidate the regulatory cascade that positions Dlx3 downstream of Wnt signaling and as an upstream regulator of other transcription factors that regulate hair follicle differentiation, such as Hoxc13 and Gata3. Colocalization of phospho-Smad1/5/8 and Dlx3 is consistent with a regulatory role for BMP signaling to Dlx3 during hair morphogenesis. Importantly, mutant catagen follicles undergo delayed regression and display persistent proliferation. Moreover, ablation of Dlx3 expression in the telogen bulge stem cells is associated with a loss of BMP signaling, precluding re-initiation of the hair follicle growth cycle. Taken together with hair follicle abnormalities in humans with Tricho-Dento-Osseous (TDO) syndrome, an autosomal dominant ectodermal dysplasia linked to mutations in the DLX3 gene, our results establish that Dlx3 is essential for hair morphogenesis, differentiation and cycling programs.
V2a and V2b neurons are generated by the final divisions of pair-producing progenitors in the zebrafish spinal cord
Authors: Kimura Yukiko , Satou Chie , Higashijima Shin-ichi
Published: August 2008

The p2 progenitor domain in the ventral spinal cord gives rise to two interneuron subtypes: V2a and V2b. Delta-Notch-mediated cell-cell interactions between postmitotic immature neurons have been implicated in the segregation of neuron subtypes. However, lineage relationships between V2a and V2b neurons have not been reported. We address this issue using Tg[vsx1:GFP]zebrafish, a model system in which high GFP expression is initiated near the final stage of p2 progenitors. Cell fates were followed in progeny using time-lapse microscopy. Results indicate that the vast majority, if not all, of GFP-labeled p2 progenitors divide once to produce V2a/V2b neuron pairs,indicating that V2a and V2b neurons are generated by the asymmetric division of pair-producing progenitor cells. Together with evidence that Notch signaling is involved in the cell fate specification process, our results strongly suggest that Delta-Notch interactions between sister cells play a crucial role in the final outcome of these asymmetric divisions. This mechanism for determining cell fate is similar to asymmetric divisions that occur during Drosophila neurogenesis, where ganglion mother cells divide once to produce distinct neurons. However, unlike in Drosophila, the divisional axes of p2 progenitors in zebrafish were not fixed. We report that the terminal division of pair-producing progenitor cells in vertebrate neurogenesis can reproducibly produce two distinct neurons through a mechanism that may not depend on the orientation of the division axis.
Component repair using laser direct metal deposition
Authors: Pinkerton A J , Wang W , Li L
Published: August 2008

Recent studies have indicated that laser direct metal deposition can be used for repairing deep or internal cracks and defects in metallic components. In order to implement the method, it is necessary to machine a groove or slot to the depth of the defect and refill it. This work investigates advantages and potential problems with the technique and compares the results from using two different slot geometries: one rectangular and one triangular in cross-section. H13 hot-work tool steel components are used and H13 powder is deposited using a 1.5 kW diode laser and lateral nozzle. Different combinations of deposition parameters are tested and each sample is analysed in terms of mass deposition rate, deposition microstructure, evidence of porosity, size of the heat-affected zone, and microhardness. Results are evaluated using statistical techniques and the important parameters that control each variable are identified. The work provides evidence that the method can produce high-quality repairs, but porosity at the boundaries between the original part and the added material is a problem.
Optimization of material requirement planning by fuzzy multi-objective linear programming
Authors: Noori S , Feylizadeh M R , Bagherpour M , Zorriassatine F , Parkin R M
Published: August 2008

Material requirement planning (MRP) has evolved from a simplistic representation in the 1980s to today's manufacturing resource planning (MRPII) and enterprise resource planning (ERP) systems in order to meet changing business demands. The persisting momentous drive for lowest costs and highest quality dictates that MRP is deployed in an optimal manner. Multi-objective linear programming (MOLP), which is used simultaneously to optimize decisions through trade-offs between two or more conflicting objectives, has not been reported in MRP-related literature. As an extension of work reported by Yenisey [1], where optimization of material flow in MRP had been presented, a fuzzy multi-objective linear programming (f-MOLP) model is used where two objectives, namely minimization of total cost and minimization of total time of MRP, are targeted. The objective is to find the optimum production rate for each end-product at each period in accordance with the objectives and related constraints. The proposed f-MOLP is solved for two sets of conditions consisting of symmetric and asymmetric cases. The corresponding results show that the proposed models can help manufacturers make better decisions when facing uncertainty about objective functions as well as the constraints set. Degrees of satisfaction demonstrate the applicability of the proposed approach in the context of MRP.
Some aspects of centrifugal force assisted abrasive flow machining of 2014 Al alloy
Authors: Reddy Malla K , Sharma A K , Kumar P
Published: August 2008

Finish machining of precision components constitutes one of the most challenging and expensive stages in a manufacturing process. Abrasive flow machining (AFM) is a non-traditional machining technique that deburrs, polishes, and radiuses surfaces and edges by flowing an abrasive-laden medium over these areas. The process is used in particular for internal shapes that are difficult to process by other non-conventional machining processes. A low material removal rate happens to be one serious limitation of this process. This paper discusses a few of the issues arising when attempting to enhance the capabilities of the conventional AFM process. In this process, a centrifugal force is imparted to the abrasive particles in the medium, making the process a hybrid one. The set-up has been suitably modified for this purpose, and the resulting process is called centrifugal force assisted abrasive flow machining (CFAAFM). The effect of key parameters on the performance of the process has been studied through response surface methodology (RSM). Relationships were developed for material removal and percentage improvement in surface finish of cast Al alloy (2014) cylindrical components. Analysis of variance (ANOVA) has been applied to identify significant parameters. Experimental results indicate the significantly improved performance of CFAAFM over AFM in terms of enhanced surface finish and material removal. It was observed that the combination of a high extrusion pressure and a higher speed of the centrifugal force generating (CFG) rod is more favourable to obtain a higher degree of surface finish, while the combination of a larger grain size and a higher speed of the CFG rod causes higher material removal.
Optimization of machining of automotive components with polycrystalline cubic boron nitride
Authors: Kountanya R K , Boppana P
Published: August 2008

While superhard cutting tools are being used increasingly in automotive plants worldwide, their adoption within the automotive supply chain is not universal. Important issues relating to successful implementation of superhard cutting tool materials in such applications include the ageing effect of grey iron, proper edge preparation of the cutting tools, and cutting conditions adopted. The paper examines quantitatively, the ageing effect on machinability of grey iron with polycrystalline cubic boron nitride (PCBN) cutting tools. The findings confirm that tool life increases with higher idle time after shakeout of the casting and the threshold period of 100 h is applicable to PCBN tools also. The benefits of using superhard cutting tools, including savings in increased uptime and cost per part and their impact on system costs, are considered in an illustrative case study. Here, it was found that imparting a wiper to the tool can beneficially increase tool life to the point of making PCBN economical to use over ceramic cutting tools and can result in relatively high savings for the plant.
Shape characteristics of microstructures in femtosecond laser multi-pulse ablation of metals
Authors: Wang W J , Mei X S , Jiang G D , Yang C J
Published: August 2008

In femtosecond laser multi-pulse ablation, the ablated surface and the fluence irradiated on this surface are ever changing. Thus, the simple summarization of single pulse ablation is not an accurate shape forecast method and the influence of beam spot change must be considered. In this paper, a new simulation method is proposed to forecast the microstructure shape, in which fluence distribution, ablation directions, and ablation rates of each pulse on the ablated surface are determined according to the spatial propagation characteristics of laser and two logarithmic ablation models. Further, the microstructure shape is obtained by accumulating the effects of all pulses. Three kinds of ablation — on-focus ablation, off-focus convergent beam ablation, and divergent beam ablation — are investigated using the proposed method. Simulation results show that the influence of beam spot change on microstructure shape is obvious. In convergent beam ablation, the structure has a sharp bottom, and the sidewall changes from concave to convex with the increase of pulses. In contrast, the structure obtained by divergent beam ablation has a much higher draft-angle and flatter bottom. On-focus ablation can be regarded as parallel beam ablation when ablations proceed within the Rayleigh range and the profile keeps to the parabola function. In experiments, microstructures are machined with three kinds of ablation in typical metals, and it is proved that the proposed structure-developing model is a valid shape forecast method when vaporization is the main ablation mechanism.
A study of roll gap adjustment due to roll wear in groove rolling: Experiment and modelling
Authors: Byon S M , Lee Y
Published: August 2008

In the tandem groove rolling process, when a certain amount of wear on the work roll exists and the roll speed is not changed, the roll gap, i.e. the section height, should be adjusted to keep a mass balance between stands, i.e. multiply the exit cross-sectional area by the roll speed between stands. To investigate the actual relationship between the amount of wear on the work roll and the subsequent exit cross-sectional area variation, the authors designed wear contours and machined them on the original roll groove, i.e. on the roll groove with no wear. They then performed a pilot hot rolling test using a work roll with a worn-down groove and one with a groove with no wear, and measured the exit cross-sectional area of the workpiece while the roll gap changed.

To predict the amount of roll gap adjustment that compensates wear, a model for roll gap adjustment is proposed. In the proposed model, the authors introduced the concept of equivalent roll gap adjustment, which reduces the increased exit cross-sectional area owing to wear up to a base exit cross-sectional area of the workpiece.

Results reveal that the exit cross-sectional area calculated by the roll gap adjustment model is in good agreement with the exit cross-sectional area measured. It has been found from the pilot hot rolling test that variation in exit cross-sectional area is almost linearly proportional to roll gap change while the roll gap decreases from a datum roll gap to about half of the datum one.
An evaluation of heat partition in the high-speed turning of AISI/SAE 4140 steel with uncoated and TiN-coated tools
Authors: Akbar F , Mativenga P T , Sheikh M A
Published: August 2008

In manufacturing by machining, thermal loads on cutting tools can have a major influence on tool wear and hence process cost, especially at higher cutting speeds. An investigation has been undertaken to determine heat partition into the cutting tool for high-speed machining of AISI/SAE 4140 high-strength alloy steel with uncoated and TiN-coated tools. The cutting tests have been performed at cutting speeds ranging between 100 and 880 m/min with a feed rate of 0.1 mm/rev and a constant depth of cut of 2.5 mm. Cutting temperatures are measured experimentally using an infrared thermal imaging camera. The sticking and sliding regions are investigated from an examination of the tool—chip contact region using a scanning electron microscope (SEM). In addition, non-uniform heat intensity is modelled according to the contact phenomena. In this work, evaluation of the fraction of heat flowing into the cutting tool is carried out by iteratively reducing the available heat flux until the finite element method (FEM) temperatures are simultaneously matched at multiple points with the experimentally measured temperatures. This paper elucidates on the differences in thermal shielding for uncoated and TiN-coated tools. It is found that heat partition into the cutting tool decreases from a fraction of 0.41 to 0.17 for conventional cutting speeds and increases from 0.19 to 0.24 for high-speed machining when using uncoated carbide cutting tools. On the other hand, with TiN-coated tools, heat partition varies from 0.35 down to 0.095 for the whole range of cutting speeds. These results clearly show that the use of TiN-coated tools generally reduces heat partition into the cutting tool, but does so more significantly in high-speed machining (HSM) as compared with conventional machining speeds. The driver behind this study on heat partition in machining with TiN coatings is the design of coatings with enhanced thermal shielding properties.
Analysis of circumferentially welded thin-walled cylinders to investigate the effects of varying clamping conditions
Authors: Malik A M , Qureshi Ejaz M , Dar N U , Khan I
Published: August 2008

Arc fusion welding predominates in the welding industry as a reliable joining method and has been the subject of investigations by researchers for decades. To ensure in-service structural integrity, optimization of weld-induced imperfections such as welding deformations and residual stresses is critically desirable in circumferentially welded thin-walled cylinders owing to their wide applications in aerospace and aeronautical structures, pressure vessels, and nuclear engineering fields. In this research, computational methodologies for sequentially coupled non-linear transient thermomechanical analysis of the complex arc welding of thin-walled cylinders of stainless steel (AISI 304) are presented. Detailed three-dimensional finite element (FE) simulations with a single V butt-weld joint configuration of 150 mm outer diameter and 3 mm wall thickness cylinders are carried out to investigate the effects of varying structural boundary conditions (mechanical constraints) on weld-induced distortions and residual stress fields. Basic FE models are validated with carefully recorded and properly instrumented experimental data for temperature distribution, deformations, and residual stresses. Predicted and measured welding distortions and residual stresses are compared and discussed in detail. The results reveal that axial deformations are strongly dependent on the degree of restraints. Low-restraint structures exhibit high axial shrinkage, and vice versa. Diametral/radial shrinkage for different clamping conditions show no significant variation. Further, residual stresses show a weak dependence on the degree of restraints. Although the stress levels slightly vary in magnitude, a similar trend is observed for all the structural clamping conditions studied.
Equilibrium and compatibility simulation of plunge centreless grinding
Authors: Jameson J R , Farris T N , Chandrasekar S
Published: August 2008

A computer simulation of plunge centreless grinding is presented. The key assumption is that the forces on the workpiece equilibrate fast enough to treat the process as a sequence of equilibrium states. Equilibrium forces are calculated at each time step, allowing machine and contact deflections to be accounted for when imposing compatibility upon the workpiece. Machine deflections of the grinding wheel, workblade, and regulating wheel are assumed proportional to the applied forces, with constants obtainable from independent experiments. Contact deflections are calculated with a Hertzian analysis and known material properties. Empirical data relating grinding force to actual depth of cut iteratively ‘close the loop’ between equilibrium and compatibility. Results of the simulation technique include histories of the workpiece shape, apparent and actual depths of cut, all forces on the workpiece, and all contact and machine deflections. It is shown that regenerative lobing is influenced by the specific grinding energy, and that actual depth of cut might be much lower, and specific grinding energy significantly higher, than in comparable surface grinding processes. It is pointed out that the application of additional, known forces to the top of the workpiece could allow equilibrium and compatibility in centreless grinding to be controlled.
Experimental investigation on the momentumless wake using trailing edge blowing
Authors: Wu Y , Zhu X , Du Z
Published: August 2008

A developed plate stator model with and without trailing edge blowing (TEB) is studied using experimental methods. Wake characteristics of flow over the stator in the three-dimensional wake regimes are studied using hot-wire anemometry (HWA) and particle image velocimetry (PIV) techniques. First, the mean velocity profiles have been measured in the wake of the stator using HWA. Four wake characteristics have been obtained through momentum thickness judgments: pure wake, weak wake, momentumless wake, and jet. These velocity profiles show some differences in momentum deficit for the four cases. Then, the velocity spectra of the pure wake and momentumless wake obtained through the HWA measurements showed that TEB can eliminate the shedding vortex of the stator. Characteristic length scales based on the wake turbulent intensity profiles showed that the momentumless wake can reduce the wake width and depth. PIV measurement is carried out to measure the flow field of the four wakes. Finally, the application of TEB approaching momentumless wake status is used on an industrial ventilation low-pressure axial fan to assess noise reduction. The results show that TEB can make the outlet of the stator uniform, reduce velocity fluctuation, destroy the vorticity structure downstream of the stator, and reduce interaction noise level of the stator and rotor.
Dual quaternion-based inverse kinematics of the general spatial 7R mechanism
Authors: Gan D , Liao Q , Wei S , Dai J S , Qiao S
Published: August 2008

The theory of dual quaternion and its use in serial mechanisms are described in this paper. A closed-form solution to the inverse kinematic analysis of the general 7-link 7R mechanism is presented. Dixon's resultant is used and the input—output equation is expressed in the form of a 6×6 determinant equated to zero, and the formulae to determine other angular displacements are expressed in the closed form. Numerical example confirms these theoretical results. The whole process is very simple and easy to program, which supplies a new method for the real use of the 7R mechanism.
Profilometry by projecting sinusoidal stripe patterns with motion blurring
Authors: Chang M
Published: August 2008

This paper proposes a method of projecting sinusoidal fringe patterns for measuring a three-dimensional shape. In the proposed method, fringe patterns are plated on a piece of glass with chromium, and each stripe of the fringe pattern is composed of small sinusoidal segments. The glass is placed on the image plane of an optical projection system. By linearly moving the glass along the direction of the stripe pattern, the projection system generates the motion-blurring phenomenon, and as a result, produces a blurred-stripe pattern whose intensity profile is sinusoidal along the direction perpendicular to the stripe pattern. Experimental results are provided for three different types of fringe patterns: rectangle, diamond, and sinusoid. Sinusoidal phase-shifted patterns generated by the proposed method produce smaller phase angle errors.
Performance analysis and optimal design of fast tool servo used for machining microstructured surfaces
Authors: Yang Y , Chen S , Huo D , Cheng K
Published: August 2008

Ultra-precision machining with a fast tool servo (FTS) is one of the leading methodologies for the fabrication of microstructured surfaces. FTS is an independently operated positioning device that plays an important role in the machining system. The complexity of surface features and the surface quality depend largely on the behaviour of FTS. In this paper, according to the analysis of required performance, a novel FTS is developed with structural parameters optimized by the finite-element analysis (FEA) method. Finally, a series of tests are carried out to evaluate the performance of the FTS and validate the value obtained by the FEA software. The results show that the FTS has a travel of 20 μm, a positioning resolution of 5 nm, a static stiffness of 33.62 N/μm, and a dominant natural frequency of 2191 Hz and demonstrate the validity of the optimal design method.
Dynamic behaviour of wind turbine blades
Authors: Hsu Ming-Hung
Published: August 2008

Wind power does not generate pollution and is a clean source. The dynamic problems associated with wind turbine blades are formulated using the differential quadrature method. The Euler—Bernoulli beam paradigm is used to characterize wind turbine blades. The differential quadrature technique is utilized to transform partial differential equations, which presents the dynamic behaviour of wind turbine blades, into a discrete eigenvalue problem. The effects of the number of sample points on the accuracy of the calculated natural frequencies are studied. Numerical results show that the rotational speed impacts significantly the first frequency of the wind turbine blade. The pitch angle could not markedly affect wind turbine blade frequencies.
Steady laminar flow of blood through successive restrictions in circular conduits of small diameter
Authors: Nag D , Datta A
Published: August 2008

In this paper, numerical results on steady laminar flow of blood through an artery having two successive identical axisymmetric restrictions are presented, at varying degrees of restrictions. Physically, such a flow has features in common with steady blood flow through an artery with multiple stenoses. Additionally, results are presented for the blood flow through an artery in the presence of a single restriction, for comparison. The artery has been modelled as a tube with a rigid wall. The rheological characteristics of blood have been assumed both as Newtonian and non-Newtonian. Three different non-Newtonian models of blood — power law, Quemada, and Carreau—Yasuda models — have been considered in the analysis. The haemodynamic effects of the restrictions on the axial velocity distribution, recirculation zones formed downstream to the restrictions, the wall shear stress, and the pressure drop in the artery have been analysed. The irreversible pressure loss coefficient is calculated from the pressure drop and its variation with the degree of stenosis is obtained.
Low-frequency damping of metal panels in ambient air
Authors: Walker S J I , Aglietti G S , Cunningham P
Published: August 2008

Mathematical models of structural dynamics are widely used and applied in many branches of science and engineering, and it has been argued that many of the shortfalls with these models are due to the fact that the physics of joint dynamics are not properly represented. Experimental analyses are, therefore, widely used to underpin any work in this area. The most renowned model for predicting the damping resulting from air pumping is based on a significant quantity of experimental data and was generally developed and applied to high frequency vibrations of jointed or stiffened panels. This publication applies this model to low frequency panel vibrations by assessing the accuracy of the model for these systems. It is concluded that the theoretical model for high stiffness joints, although generally over approximating the damping magnitude, gives a good conservative estimate of the increase in damping due to air pumping for low frequency vibrations.
Measurements of Reynolds stresses in centrifugal compressor vaned diffusers
Authors: Pinarbasi A , Guleren K M , Ozturk A
Published: August 2008

A phase lock loop sampling technique has been developed in order to perform detailed measurements for the flow field downstream of a turbomachinery rotor. Measurements have been carried out in the vaned diffuser of a low-speed centrifugal compressor using a triple hot wire anemometer. The phase lock loop technique employed in this work has provided a comprehensive representation of the complex three-dimensional unsteady flow in these diffusers. The diffuser vanes were found to have a significant influence on the flow in the vaneless space. The mixing out of the blade wakes is enhanced and accordingly the Reynolds stress levels drop rapidly between the impeller exit and the vane leading edge. The results provide an insight into the flow mechanisms responsible for the losses and hence can be used to develop better design strategies in the future. The flow also exhibits high levels of anisotropy, especially at the mid-vane positions. This suggests that basic Reynolds-averaged Navier—Stokes (RANS) models, including standard one- or two-equation models, might not be sufficient to accurately model the flow in centrifugal compressor diffusers.
Analysis and design of a four-cable-driven parallel manipulator for planar and spatial tasks
Authors: Ottaviano E
Published: August 2008

In this paper, the design and kinematic performances are presented for a parallel manipulator with four driven cables. Kinetostatic analysis has been performed for both planar and spatial operations of the manipulator as based on a geometrical approach. A low-cost prototype has been built and an application is proposed to show the feasibility of the system design and its operation.
Flow over two tandem wall-mounted cubes using large eddy simulation
Authors: Farhadi M , Sedighi K
Published: August 2008

Flow over tandem surface-mounted cubes in a channel were investigated numerically using large eddy simulation (LES). The selective structure function model used for the determination of eddy viscosity appears in the subgrid scale stress terms in momentum equations. Flow over this geometry has very complex phenomena such as several horseshoe vortices and recirculation regions. The main objective of this study is identifying the features of flow past two in-line wall-mounted cubes in a channel for Reynolds number 22 000. The LES results obtained are in reasonable agreement with the experiment both qualitatively and quantitatively. The time-averaged streamlines and velocity vectors were compared with the experiment of Martinuzzi and Havel [9], which showed good correspondence. The S/ H length has negligible influence on the turbulence levels in the region upstream and above the first cube in the separation zone. However, in the vortex core downstream of, and above the second cube, elevated levels of turbulence were found for both u′ u′ and v′ v′ especially when the inter-obstacle spacing is increased. A result of this study also includes time-averaged contours of turbulent intensity and some details of flow parameters such as the Strouhal number and drag coefficient.
Improvement of induction motor fault diagnosis performance by using genetic algorithm-based feature selection
Authors: Nguyen N-T , Lee H-H
Published: August 2008

In this study, features are extracted from time vibration signals for the purpose of diagnosing motor faults. On the basis of the specific distance criterion, a simple genetic algorithm (GA) is employed to evaluate and select the optimized features for induction motor fault classification. The selected features are applied to the decision tree and the k-nearest neighbour (k-NN) algorithm in order to show the efficiency of the proposed feature selection method. The diagnostic results show that the optimal feature selection is useful to improve the fault diagnosis performance.
A Review of exoskeleton-type systems and their key technologies
Authors: Yang C-J , Zhang J-F , Chen Y , Dong Y-M , Zhang Y
Published: August 2008

The exoskeleton-type system is a brand new type of man—machine intelligent system. It fully combines human intelligence and machine power so that machine intelligence and human operator's power are both enhanced. Therefore, it achieves a high-level performance that neither could separately. This paper describes the basic exoskeleton concepts from biological system to man—machine intelligent systems. It is followed by an overview of the development history of exoskeleton-type systems and their two main applications in teleoperation and human power augmentation. Besides the key technologies in exoskeleton-type systems, the research is presented from several viewpoints of the biomechanical design, system structure modelling, cooperation and function allocation, control strategy, and safety evaluation.
Implementation of Whitehouse's method for calculating properties of self-affine fractal profiles
Authors: Thomas T R , Rosén B-G
Published: August 2008

Many software packages for roughness analysis offer the possibility of calculating the fractal dimension D of surface profiles by techniques, which assume them to be self-similar and therefore uniquely defined by D. However, fractal profiles are not self-similar but self-affine, so that two profiles of quite different roughnesses may share the same fractal dimension. To distinguish between them requires the calculation of an additional scaling factor, the so-called topothesy Λ. Traditionally, D and Λ are derived laboriously from the slope and intercept of the profile's structure function. A quicker and more convenient derivation from standard roughness parameters has been suggested by Whitehouse. Based on this derivation, it is here shown that D and Λ depend on two dimensionless numbers: the ratio of the mean peak spacing to the rms roughness and the ratio of the mean local peak spacing to the sampling interval. Using this approach, values of D and Λ are calculated from the measurements on surface profiles produced by polishing, plateau honing, and various single-point machining processes. Different processes are shown to occupy different regions in D–Λ space, and polished surfaces show a relationship between D and Λ, which is independent of the surface material.
An analysis of turbulent film boiling on a sphere with variable wall temperature
Authors: Hu H-P
Published: August 2008

The present theoretical study investigates turbulent film boiling on a sphere immersed in a stagnant saturated liquid. By assuming the cosine function, the condition of variable wall temperature is expressed. The study includes the analysis of non-linear vapour velocity, vapour temperature, thermal property, and Eddy diffusivity in the vapour film; the radiation effect, temperature ratio, and the Rayleigh number are all considered. The result shows that in a free-convection film, when film boiling has higher Rayleigh number, the turbulent film boiling has a better heat transfer efficiency than the laminar one. Finally, a comparison between the results of the present study and those reported in previous studies is presented. It is found that a good agreement exists between them.
Vibration characteristic of laminated sandwich plates with soft core based on an improved higher-order zigzag theory
Authors: Pandit M K , Sheikh A H , Singh B N
Published: August 2008

This paper presents an improved higher order zigzag theory for vibration of laminated sandwich plates. It ensures continuity of transverse shear stresses at all the layer interfaces and transverse shear stress-free condition at the top and bottom surfaces apart from core compressibility. The through-thickness variation of in-plane displacements is assumed to be cubic, whereas transverse displacement varies quadratically across the core, which is modelled as a three-dimensional elastic continuum. An efficient C0 finite element is developed for the implementation of the plate theory. The model is validated using three-dimensional elasticity solutions and some other relevant results available in the literature.
Parametric study on friction-induced coupled oscillator
Authors: Kang Jaeyoung
Published: August 2008

This paper investigates the dynamic instability of a sliding oscillator subjected to non-linear friction force. The dynamic instability is determined by the system eigenvalues of the linearized equation of motion. Mode-coupling type instability and negative slope type instability are considered to be the mechanism generating the friction-induced vibration. The mode coupling between two vibration modes strongly depends on the system parameters such as the spring inclination angle. The conditions for the divergence and dynamic instability are presented in the mathematical form. The damping coefficient of an inclined support arm is seen to determine the modal damping separation influencing on the dynamic instability.
Optimal performance of an endoreversible chemical engine with diffusive mass transfer law
Authors: Chen L , Xia D , Sun F
Published: August 2008

The performance of an isothermal endoreversible chemical engine, in which the mass transfer obeys diffusive law, is analysed and optimized in this paper. The analytical relations about power output and efficiency, as well as the optimal relation between the power output and efficiency of the isothermal chemical engine are derived by using finite-time thermodynamics. Moreover, the optimal operating regions are studied. The results obtained herein can provide some new theoretical guidelines for the optimal design and development of a class of chemical engines.