bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in Memory Function and Neuronal Activation Associated with Atorvastatin Therapy
Authors: Parker Beth A. , Polk Donna M. , Rabdiya Vimal , Meda Shashwath A. , Anderson Karen , Hawkins Keith A. , Pearlson Godfrey D. , Thompson Paul D.
Published: March 2011

A small number of case studies have reported statin‐induced dementia or memory loss that resolves with cessation of statin therapy. However, such reports have not, to our knowledge, been substantiated by objective measures of changes in brain function during statin treatment and after discontinuation of the drug. We describe a 65‐year‐old man who reported cognitive complaints (memory complaints and mood changes) after taking atorvastatin 10 mg/day for 1 year. He had no history of alcohol consumption, major head trauma, psychiatric problems, or memory impairment. Cognitive testing (Hopkins Verbal Learning Test‐Revised, Brief Visuospatial Memory Test‐Revised, and Wechsler Adult Intelligence Scale, third edition, digit symbol coding and digit span tests) and assessment of neuronal activation using functional magnetic resonance imaging (fMRI) were performed during a working memory task (Sternberg Task) while he was receiving atorvastatin therapy. The patient demonstrated altered neuronal activation (reduced activation of the dorsolateral prefrontal cortex during the encoding task phase and hyperactivation of multiple areas of the prefrontal cortex during the recognition task phase) and reduced performance on the cognitive tests, which was consistent with his cognitive symptoms. These measurements were repeated 2 months after discontinuation of the drug. The patient exhibited improved cognitive test performance and fMRI patterns similar to those expected in a healthy individual. The patient also reported subjective improvement of his cognitive complaints within days of cessation of atorvastatin, which persisted at follow‐up 5 months later (while refraining from any statin use in the interim). To our knowledge, this is the first case report to describe objective cognitive and fMRI findings substantiating statin‐associated effects on the central nervous system, and it provides preliminary evidence that fMRI may be a useful technique for evaluating cognitive function in adults treated with statins.
Falsely Elevated Tacrolimus Levels Caused by Immunoassay Interference Secondary to β‐Galactosidase Antibodies in an Infected Liver Transplant Recipient
Authors: Knorr John P. , Grewal Kevin S. , Balasubramanian Manjula , Young Nancy , Zaki Radi , Khanmoradi Kamrin , Araya Victor , Ortiz Jorge
Published: March 2011

Careful interpretation of tacrolimus levels is essential to ensure optimal immunosuppressive therapy while avoiding toxicity. Interference with tacrolimus assays may be an underreported event that has the potential to result in negative patient outcomes through unnecessary modifications of therapy. We describe a 55–year‐old liver transplant recipient who had falsely elevated tacrolimus levels that led to the eventual disruption of his immunosuppressive therapy and subsequent rejection of his allograft. Although his increased tacrolimus levels did not correlate with clinical signs and symptoms of tacrolimus toxicity, interruption of therapy in this patient was supported by an acute infection and a slight elevation in serum creatinine concentration. Tacrolimus levels were analyzed by using an antibody conjugated magnetic immunoassay method, and levels as high as 79.7 ng/ml were observed, despite discontinuation of tacrolimus. We conducted an evaluation for assay interference by using an alternative assay method (microparticle enzyme immunoassay), by testing plasma samples that were not hemolyzed, and by analyzing levels of an unrelated drug that uses the same technology as the initial tacrolimus assay. β‐Galactosidase antibodies were ultimately confirmed as the cause of the immunoassay interference. In patients receiving tacrolimus, spuriously high tacrolimus levels should be carefully evaluated, and drastic adjustments to therapy should be made only within the context of clinical toxicity.
Multiple Myeloma Treatment Strategies with Novel Agents in 2011: A European Perspective
Authors: Ludwig Heinz , Beksac Meral , Bladé Joan , Cavenagh Jamie , Cavo Michele , Delforge Michel , Dimopoulos Meletios , Drach Johannes , Einsele Hermann , Facon Thierry , Goldschmidt Hartmut , Harousseau Jean-Luc , Hess Urs , Kropff Martin , Leal da Costa Fernando , Louw Vernon , Magen-Nativ Hila , Mendeleeva Larisa , Nahi Hareth , Plesner Torben , San-Miguel Jesús , Sonneveld Pieter , Udvardy Miklos , Sondergeld Pia , Palumbo Antonio
Published: March 2011

The arrival of the novel agents thalidomide, bortezomib, and lenalidomide has significantly changed our approach to the management of multiple myeloma and, importantly, patient outcomes have improved. These agents have been investigated intensively in different treatment settings, providing us with data to make evidence-based decisions regarding the optimal management of patients. This review is an update to a previous summary of European treatment practices that examines new data that have been published or presented at congresses up to the end of 2010 and assesses their impact on treatment practices.
External Quality Assessment for KRAS Testing Is Needed: Setup of a European Program and Report of the First Joined Regional Quality Assessment Rounds
Authors: Bellon Ellen , Ligtenberg Marjolijn J.L. , Tejpar Sabine , Cox Karen , Hertogh Gert , Stricker Karin , Edsjö Anders , Gorgoulis Vassilis , Höfler Gerald , Jung Andreas , Kotsinas Athanassios , Laurent-Puig Pierre , López-Ríos Fernando , Hansen Tine Plato , Rouleau Etienne , Vandenberghe Peter , Krieken Johan J.M. , Dequeker Elisabeth
Published: March 2011

Learning Objectives

After completing this course, the reader will be able to: Identify the most frequent errors made in KRAS testing in this study and the possible consequences for a patient.Describe factors that could increase the chance of an error during KRAS testing.

This article is available for continuing medical education credit at CME.TheOncologist.com

The use of epidermal growth factor receptor–targeting antibodies in metastatic colorectal cancer has been restricted to patients with wild-type KRAS tumors by the European Medicines Agency since 2008, based on data showing a lack of efficacy and potential harm in patients with mutant KRAS tumors. In an effort to ensure optimal, uniform, and reliable community-based KRAS testing throughout Europe, a KRAS external quality assessment (EQA) scheme was set up. The first large assessment round included 59 laboratories from eight different European countries. For each country, one regional scheme organizer prepared and distributed the samples for the participants of their own country. The samples included unstained sections of 10 invasive colorectal carcinomas with known KRAS mutation status. The samples were centrally validated by one of two reference laboratories. The laboratories were allowed to use their own preferred method for histological evaluation, DNA isolation, and mutation analysis. In this study, we analyze the setup of the KRAS scheme. We analyzed the advantages and disadvantages of the regional scheme organization by analyzing the outcome of genotyping results, analysis of tumor percentage, and written reports. We conclude that only 70% of laboratories correctly identified the KRAS mutational status in all samples. Both the false-positive and false-negative results observed negatively affect patient care. Reports of the KRAS test results often lacked essential information. We aim to further expand this program to more laboratories to provide a robust estimate of the quality of KRAS testing in Europe, and provide the basis for remedial measures and harmonization.
Stability and Hopf bifurcation analysis for a Lotka-Volterra predator-prey model with two delays
Authors: Xu Changjin , Liao Maoxin , He Xiaofei
Published: March 2011

Stability and Hopf bifurcation analysis for a Lotka-Volterra predator-prey model with two delays

In this paper, a two-species Lotka-Volterra predator-prey model with two delays is considered. By analyzing the associated characteristic transcendental equation, the linear stability of the positive equilibrium is investigated and Hopf bifurcation is demonstrated. Some explicit formulae for determining the stability and direction of Hopf bifurcation periodic solutions bifurcating from Hopf bifurcations are obtained by using normal form theory and center manifold theory. Some numerical simulations for supporting the theoretical results are also included.
Neural network based feedback linearization control of a servo-hydraulic vehicle suspension system
Authors: Pedro Jimoh , Dahunsi Olurotimi
Published: March 2011

Neural network based feedback linearization control of a servo-hydraulic vehicle suspension system

This paper presents the design of a neural network based feedback linearization (NNFBL) controller for a two degree-of-freedom (DOF), quarter-car, servo-hydraulic vehicle suspension system. The main objective of the direct adaptive NNFBL controller is to improve the system's ride comfort and handling quality. A feedforward, multi-layer perceptron (MLP) neural network (NN) model that is well suited for control by discrete input-output linearization (NNIOL) is developed using input-output data sets obtained from mathematical model simulation. The NN model is trained using the Levenberg-Marquardt optimization algorithm. The proposed controller is compared with a constant-gain PID controller (based on the Ziegler-Nichols tuning method) during suspension travel setpoint tracking in the presence of deterministic road disturbance. Simulation results demonstrate the superior performance of the proposed direct adaptive NNFBL controller over the generic PID controller in rejecting the deterministic road disturbance. This superior performance is achieved at a much lower control cost within the stipulated constraints.
Triangulating Principal Effectiveness
Authors: Grissom Jason A. , Loeb Susanna
Published: March 2011

While the importance of effective principals is undisputed, few studies have identified specific skills that principals need to promote school success. This study draws on unique data combining survey responses from principals, assistant principals, teachers, and parents with rich administrative data to determine which principal skills correlate most highly with school outcomes. Factor analysis of a 42-item task inventory distinguishes five skill categories, yet only one of them, the principals’ Organization Management skills, consistently predicts student achievement growth and other success measures. Analysis of evaluations of principals by assistant principals supports this central result. The analysis argues for a broad view of principal leadership that includes organizational management skills as a key complement to the work of supporting curriculum and instruction.
School Start Times and the Sleep–Wake Cycle of Adolescents
Authors: Kirby Matthew , Maggi Stefania , D’Angiulli Amedeo
Published: March 2011

The authors have integrated the major findings on the sleep–wake cycle and its performance correlates in adolescents. Basic research shows that lack of synchronicity between early school start times and the circadian rhythm of adolescents (and the sleep debt accumulated as a result) involves several cognitive correlates that may harm the academic performance of adolescent students. The authors therefore examined findings from pilot interventions in which schools delayed their start times; specifically, they examined the effects on students, including potential pitfalls and strategies to consider for effective scheduling change. There is sufficient evidence that adolescent students would benefit from delaying school start times and that this change can be implemented with tolerable consequences if adequately strategized by school districts and communities.
Indulgences et sensibilité ultramontaine dans la France du XVIIIe siècle : à partir du cas breton
Authors: Provost Georges
Published: March 2011

Issu de l'observation d'un renouveau spectaculaire de la tradition médiévale de l'indulgence dans la Bretagne des XVIIe et XVIIIe siècles, cet article vise à replacer l'exemple breton dans l'ensemble du royaume grâce à une exploitation des archives romaines pour les deux dernières décennies de l'ancien Régime : celles-ci confirment la forte demande des diocèses bretons, participant d'une France Ultramontaine unie à Rome par de puissants liens institutionnels. L'indulgence révèle ainsi, au sein du catholicisme français, la diversité des sensibilités, sinon les inégalités de la ferveur, dès avant la Révolution.
Violence et discours au XVIIIe siècle
Authors: Pitou Frédérique
Published: March 2011

The study of complaints for « assault and battery » fîled in courts allows us to get an insight into the frequency of violence and its double meaning. It can be of the common-place, every sort, a harmless glitch in ordinary social relations ; it can also be the first response to an aggression from the outside. But the tales reconstituted here conform to a certain number of standards of the genre. They provide information less on violence itself and the reasons of violent behaviours (which they try on the contrary to conceal) than on the manner of reporting violence, through a rhetoric that must be efficient in a court hearing. The behaviours likely to win the magistrates' sympathy are well-known and the complaints display the canons of the model behaviours, as spread well beyond the court hearings. Besides, the meanderings of the procedure seem to be well understood, even in the most popular classes, and the ordinary plaintiffs are far from being lost. The answers given to the judge during the examination witness the implementation of highly coherent strategies and make use of rhetoric in a fairly deft manner. One may even assume that the popular language, as reported in the court' s records, with its common use of hackeyed phrases or even ready-made retorts, as a mean not to stay or not to answer, is perfectly suited to court dealings, even shaped by them.
Un collectionneur provincial vu par ses contemporains : le Président de Robien (1698-1756)
Authors: Aubert Gauthier
Published: March 2011

Les collections du président au parlement de Bretagne Christophe-Paul de Robien (1698-1756) ont jusqu'ici été étudiées à partir de ce qui nous est parvenu des saisies révolutionnaires de 1794, événement fondateur des musées de Rennes. L'exploitation des témoignages écrits et iconographiques de ceux qui, au XVIIIe siècle, ont vu les collections Robien permet une nouvelle approche dans laquelle la notion de perception est privilégiée, et qui met en avant plus le collectionneur que les collections. Dès lors, l'image d'une collection jugée intéressante par ses œuvres d'art et ses objets exotiques cède la place à celle d'un amateur avant tout d'histoire naturelle et d'antiquités, collectionnant dans un esprit empruntant aux Lumières et à la Renaissance. Enfin, il apparaît que, pour les contemporains, une collection de cette ampleur était unique en Bretagne au XVIIIe siècle.
Les magistrats de la cour d'appel d'Angers : entre méritocratie et auto-reproduction d'une compagnie judiciaire de province (1848-1883)
Authors: Bernaudeau Vincent
Published: March 2011

The study of social trajectories, economic positions and standings education of these hundred and nine magistrates having sat at the Court of Angers between 1848 and 1883, underlines the persistence of the angevin judicial corps' self reproduction rather than the real «démocratisation » of magistrate' s profession. Family, recommendations and fortune still widely condition the admission to the career during the second half of the XIXth century and the development of the meritocracy can not erase the predisposition to professional heredity of a corps which incarnates social preservation.
Environmental control of the annual erect phase of Nemalion helminthoides (Rhodophyta) in the field
Authors: Pato Lorena S. , Martínez Brezo , Rico José M.
Published: March 2011

In temperate areas, lack of nutrients during summer, particularly N, is the main limiting factor of macroalgal growth. However, Nemalion helminthoides (Velley) Batters in northern Spain is conspicuous in the field during this time (from mid-May to late-July). Therefore, we assumed that its nutrient requirements are low enough to be sustained by transient nutrient inputs and we hypothesized that the physiological condition of the thalli was transiently improved when nutrient pulses occurred. A range of proxies for physiological condition (internal N, C, proteins and phycobilins), growth and phenological status of N. helminthoides were measured over time and related to temporal variations in nutrient availability, irradiance, temperature and daylength. Data were analyzed using a multivariate approach (redundancy analysis). Transient nutrient inputs were mainly due to freshwater runoff and wind-driven upwelling events; however, these pulses did not lead to any short-term improvement in the physiological condition of the algae because in such dominant nutrient limiting conditions plants divert transient available resources directly to growth and reproduction. Probably because of the strong endogenous nature of the N. helminthoides life-history, only daylength and temperature were found to be major environmental factors: increasing daylength was associated with growth, sexual maturation, fertilization and the increment of internal N and C, the amount of proteins and phycobilins. Decreasing daylength together with increasing temperature were correlated with spore release and senescence. This research suggests that N. helminthoides requires a high light dose to sustain growth and reproduction, and therefore it must grow and reproduce in summer even though it has to overcome nutrient deprivation during this period.
Effects of organic pollution in the distribution of annelid communities in the Estero de Urías coastal lagoon, Mexico
Authors: Ferrando Agustín , Mendez Nuria
Published: March 2011

The Estero de Urías coastal lagoon is subjected to several anthropogenic activities and has been characterized since 1997 through the study of benthic fauna. We analyzed the spatial and temporal distribution of annelids and their relationships with environmental variables (depth, sediment temperature, grain size and organic matter) in order to determine the current degree of perturbation. Density, species richness, diversity, dominance, biomass, and the application of classification and ordination techniques allowed us to distinguish 5 zones: 1) a non-perturbed zone at the mouth of the lagoon, 2) a slightly perturbed zone surrounded by mangroves and shrimp farms, 3) a temporarily perturbed zone close to the effluent of the thermoelectric plant, 4) a perturbed zone in front of the slaughterhouse and fish factory, and 5) a very perturbed zone subjected to sewage and industrial input. Only minor changes in granulometry and faunal composition were observed in comparison with previous data from the same area, suggesting that the lagoon is still perturbed due to the effect of anthropogenic activities.
Incidence and significance of cystic structures in the ovaries of gadoid fish
Authors: Domínguez-Petit Rosario , Alonso-Fernández Alexandre , Saborido-Rey Fran
Published: March 2011

Fish regulate egg production by atresia. Sometimes, oocytes are encapsulated in cystic structures that might remain in the ovary for months, altering female reproductive potential in future spawning seasons. Ovaries of Atlantic cod (Gadus morhua, L.) from the Flemish Cap and European hake (Merluccius merluccius, L.) from the Galician Shelf (NW Spain) were analysed from 1999 to 2006. The prevalence and abundance of ovarian cysts were estimated. Cyst prevalence increased with female size and/or age for both species, and decreased with high condition factor in hake. Cyst intensity does not correlate with any analysed factor. The size/age structure of spawning stock biomass and female condition could affect the prevalence of cysts in the ovaries, though it does not seem to affect cyst intensity in the ovary. Further research is needed to determine cyst resorption time and the impact that it has on egg production and consequently on stock reproductive potential.
Size-fractionated phytoplankton biomass and production in the tropical Atlantic
Authors: Moreno-Ostos Enrique , Fernández Ana , Huete-Ortega María , Mouriño-Carballido Beatriz , Calvo-Díaz Alejandra , G. Morán Xosé Anxelu , Marañón Emilio
Published: March 2011

Two meridional transects were conducted in the tropical and subtropical Atlantic to describe (i) the spatial variability of total and size-fractionated (picophytoplankton and phytoplankton > 2 μm) chlorophyll a (chl a) concentration and primary production, (ii) the relative contribution of each phytoplankton size fraction to total biomass and carbon fixation, and (iii) the spatial variability of size-fractionated phytoplankton growth rate (P/B) and assimilation number (P/chl a) in the ocean. The highest chl a for both size fractions was observed in the Western Tropical Atlantic province (WTRA), while the lowest chl a was found in the upper mixed layer (UML) of the South Atlantic Tropical gyre (SATL). A similar pattern was found for carbon fixation. Within the SATL, the highest picophytoplankton contribution to total production was recorded at the Deep Chlorophyll Maximum (DCM), while the contribution of phytoplankton > 2 μm was higher in the UML. Additionally, the relative contribution of large phytoplankton to total integrated primary production was higher than its contribution to total biomass. Both size fractions depicted maximum P/B and P/chl a in WTRA surface waters. In the SATL province, phytoplankton > 2 μm showed the highest P/B and P/chl a along the UML, while picophytoplankton P/B and P/chl a peaked around the DCM. We suggest that the differential impact of light on small and large phytoplankton may help to explain the contrasting dynamics of the two size classes.
Study on the Cutting Force of Inconel 718 Machined by Different Cutting Tools
Authors: Geng Guo Sheng , Xu Jiu Hua , Fu Y.C. , Yang B. , Su L.L.
Published: March 2011

Inconel 718 is widely used in aerospace, nuclear power and gas turbine industries. On the other side, it is well known as one of the most difficult-to-cut super alloy and its efficient machining assumes a lot of importance. Therefore, this paper presents an experimental investigation on the cutting force of Inconel 718 machined with several different kinds of cutting tools. Both single-factor and orthogonal experiments were carried out with cemented carbide, cermet and CBN tools. The effects of cutting tools and cutting parameters on the cutting force are investigated and the optimal cutting conditions are recommended.
The Identification of Vibration Characteristics for Hardened Steel Based on Wavelet Energy Spectrum in High-Speed Milling
Authors: Wang Yan Xin , Liu Xian Li , Yue C.X. , Xiao Fei , Sun P.
Published: March 2011

A method to identify the effect of tool overhang on vibration signal is put forward to study machining process of large hardened steel automobile mold by wavelet energy spectrum. Firstly, collect the machinery vibration signal on milling by displacement sensor, then make a wavelet transform on time signal and calculate the wavelet energy spectrum of each frequency range. Finally, extract energy value of the right frequency by the method of homogenization. It is confirmed by experimental data that this method can recognize vibration feature and abnormal condition of cutting tool in high speed milling process of hardened steel fleetly and efficiently.
Temperature Variables Selection for Thermal Error Modeling of Heavy-Duty CNC Milling-Boring Machine Tools
Authors: Cui Gang Wei , Gao D. , Wang L. , Yao Y.X.
Published: March 2011

One of the difficult issues in thermal error modeling is to select appropriate temperature variables. In this paper, two selection strategies are introduced to overcome this difficulty. After measuring the temperatures and thermal errors of a heavy-duty CNC milling-boring machine tool by a laser tracker, four temperature variables which are the foundation of thermal error modeling are selected for each feed axis from fifteen temperature variables according to major factor strategy and non-interrelated strategy.
The Study on Three-Dimensional Roughness of Machined Surface in High Speed Milling of SiCp/Al Composites
Authors: Wang Yang Jun , Zhou M. , Zhao Y.H.
Published: March 2011

For the purpose of investigating the effect on surface micro-topography of cutting parameters in high speed milling of SiCp/Al Composites, the high speed milling experiments were performed .The machined surface was measured by Taylor Hobson roughness tester and OLS3000 Confocal Laser Scanning Microscope. The acquired surface data was dealt with the three-dimensional roughness method. The three-dimensional root-mean-square deviation of the surface Sq and two-dimensional root-mean-square deviation Rq were compared. The effects of cutting parameters on three-dimensional roughness parameter were also investigated. The results showed that both feed rate and depth of cut have a little effect on the value of three-dimensional roughness parameter，and the cutting speed is the main affecting factor.
Analysis of the Nanoscale Manipulation Using Near-Field Optical Tweezers Combined with AFM Probe
Authors: Liu Bing Hui , Yang Li Jun , Tang J. , Wang Yang , Yuan Ju Long
Published: March 2011

In recent years, optical manipulators based on forces exerted by enhanced evanescent field close to near-field optical probes have provided the access to nonintrusive manipulation of nanometric particles. However, the manipulation capability is restricted to the intensity enhancement of the probe tip due to low emitting efficiency. Here a near-field optical trapping scheme using the combination of an optical fiber probe and an AFM metallic probe is developed theoretically. Calculations are made to analyze the field distributions including tip interaction and the trapping forces in the near-field region by applying a direct calculation of Maxwell stress tensor using three-dimensional FDTD. The results show that the scheme is able to trap particle at the nanoscale with lower laser intensity than that required by conventional near-field optical tweezers.
Research on Dynamic Constitutive Relation of Materials Taking Account of Damage Evolution and Fracture Law for High Speed Cutting
Authors: Li J.Q. , Dong Tao Tao , Wang Min Jie
Published: March 2011

The adiabatic shear, which may produce serrated chip, usually occurs for a large number of materials in high speed machining. Adiabatic shear band is an important damage model for metals under high-velocity deformation process. The damage evolution of micro-voids in adiabatic shear bands resulted in material fracture finally. Now the thermal softening effect, the strain rate harding effect and the strain harding effect have been discussed extensively in literature, but there is very little research on its damage effect. Based on the experiments of predecessors, this paper presents a new damage evolution equation that is dependent on strain, strain rate and is suitable for the description of voids damage evolution in adiabatic shear band. The corresponding rate-dependent constitutive relation taking account of damage evolution and temperature are proposed. The predicted results are in good agreement with the experiment datum.
The Experimental Study about the Influence of Extrusion System Parameters on Textured Degree of High Moisture Content Fibriform Imitated Meat
Authors: Sun P.L. , Jiang L.Z. , Sun Y. , Sun Z.L. , Xie T.M. , Cao Y.
Published: March 2011

The high-emulation meat with 60% ~ 80% moisture content made use of high humidity extrusion technology was prepared with soybean protein isolate, defatted soybean meal and wheat gluten as main raw materials. The effect of extrusion system parameters (extrusion temperature, screw rpm , moisture content and soybean protein isolate content) on product textured degree was studied. Results showed that: the influence of the moisture content on the product textured degree was the most important, and screw speed was less influential. The textured degree of high moisture content fibriform imitated meat increased first and then decreased with the increasing of extrusion temperature, screw rpm, moisture content and soybean protein isolate content. So, better textured degree could be received by increasing the parameters to advisable numerical value, and the product would have an obvious fibroid structure. The conclusion could also be used as a value reference in the production of high-emulation meat of livestock and poultry. At present, we are committed to produced emulation meat with soy protein. High moisture extraction[1] is jointly developed by Clextral Co. France and Pro. Co.Ltd was one way of producing simulation meat. This technology, with special cooling die head twin-screw extruder for main equipment, prepared textured soy protein production at the moisture content of material higher than 45%. It had been discovered that with the increase of moisture content of textured soy protein the textured rate of production would be increased. The elastic, resiliency and fibroid structure would be much more like the animal meat. At present, extrusion of material moisture higher than 60% could not be achieved in the domestic. The twin-screw extruding technology on soy protein with moisture content 60%~80% was studied in this subject. Production condition of high moisture content fibrous imitated meat would be established and technical features would be supplied to domestic extruding equipment through the influence of extruding temperature, material moisture content, screw speed and material composition on soy protein molecular recombination and fibrosis.
Analysis on the Microstructure of Carbide Reamers after the Cryogenic Treatment
Authors: Niu Qiu Lin , An Qing Long , Chen Ming , Liu Gang , Wang Cheng Yong
Published: March 2011

The cryogenic treatment is an extension of the cold processing technology by which the material properties could be changed. This provides a new method for people to improving the performance of the cutting tools and prolonging the tool life. The micro-structure of two unknown types of carbide reamers after different cryogenic treatment was introduced in this paper. From the metallographic microstructure, SEM microstructure, EDS spectrum analysis and the hardness measurement, the detailed analysis on the microstructure of the reamers (1# and 2#) was provided in this paper. The results show that the matrix materials of the two reamers were the WC-Co cemented carbide, and they were the ultra-fine grain carbide (＜500nm); 2# reamer belonged to the high Co cemented carbide reamer. By the cryogenic treatment, the hardness of two reamers has increased. And the value of the hardness for 1# reamer was higher than that for 2#.
Research on Dynamic Characteristics of High-Speed Machining Aluminum Alloy Blades
Authors: Liu Y.B. , Zhang Yong De , Zhao Can
Published: March 2011

High-speed machining aluminum alloy blades, often can generate chatter. The static modal experiment and dynamic cutting test method was used to get the influence factors. It studied the change of blade modal during the material removal process according the experiments since the thin blade and large influence to its stability of the removal of blank. Through the study it was found that there are two modes of blades within the scope of sensor’s detecting. Blade modal frequency appears to first increase then decrease during the material removal process with little vibration. The dynamic experiment analysis the factor of cutting force in five-axis milling process and messures five-axis machining cutting force in various parameters. It was observe that distribution of 3-dimension cutting forces in cutting path. It was found that the distribution rule of cutting force. Resultant cutting force was increased with cutting speed increased.
Modeling of Thrust Force and Tool Wear and Optimization of Process Parameters in Drilling Nickel-Based Alloy GH536
Authors: Wang M.H. , Huang Shu Tao
Published: March 2011

. In this study, the prediction models of thrust force, tool wear and torque in drilling nickel-based alloy GH536 are developed based genetic algorithm and drilling experiments. Tool wear value is used as constraint condition and maximum cutting efficiency as goal to optimize drilling process parameters. In addition, the relationship between tool life and cutting efficiency is analyzed by exploiting the tool wear prediction model. The results of the analysis show that under the condition of efficiency remains unchanged, the tool life can be increased by increasing drilling speed and appropriately reducing feed rate, these results are consistent with the optimized process parameters.
Research on Fabrication Technology and Hydraulic Performance of Multi-Point Gear Flow Dividers
Authors: Li Xi Bing , Liu X.L. , Shi Z.M. , Hu Q.M. , Wang S.G.
Published: March 2011

With the rapid development of static-press technique, multi-point constant oil supply system has been widely applied into bearing the work table of large CNC vertical turning machine. A group method has been proposed through the analysis of the operating principle, structural features and manufacturing method of multi-point gear flow dividers. Then the diversion characteristics of the twelve point gear flow dividers manufactured through this method are compared with those of the dividers alike both at home and abroad. The experimental results show that the multi-point gear flow dividers manufactured through this group method not only have good diversion accuracy , but reduce the manufacturing cost and assure workbench’s running stability as well as high quality and precision products.
Combining Multiaxis Machining and Burnishing in Complex Parts
Authors: López de Lacalle Luis Norberto , Rodríguez Adrián , Lamikiz Aitzol , Celaya Ainhoa
Published: March 2011

In this paper the ball burnishing as a finishing process for sculptured surfaces is studied. This technique is a quick, easy and economical process for a significant improvement of high-end parts. Aiming at the burnishing of complex parts, different strategies are possible. In this case two strategies are presented: continuous burnishing (CB) using 5-axis interpolation and patch burnishing (PB) using 3+2 axis interpolation. Two parts have been previously machined in five-axis and then finished using ball burnishing techniques. The first one is an AISI 1045 hemisphere and the second one is a DIN 1.2379 part (64 HRC). Surface quality has been evaluated for both strategies obtaining a significant improvement of surface roughness and hardness.
Research on Ram Thermal Deformation Real-Time Compensation of Large Floor Type Boring-Milling Machine
Authors: Lu Yong , Gao Dong , Liu Yi Lei , Sun Z.
Published: March 2011

Ram is a very important component of heavy-duty floor type boring-milling machine, and thermal deformation is a significant source causing errors in machining process. The law of thermal deformation of ram is researched for real-time compensation for thermal deformation error of ram. Meanwhile, DRF function compensation is proposed based on 840D NC system. Real-time error compensator is made and proved to be available by experiment.
Simulation for Sinusoidal Spindle Speed Variation Cutting in Time Domain Based on Simulink
Authors: Mao Kuan Min , Zhang Min , Zhu Ming , Yin Ling
Published: March 2011

This paper presents a simulink block diagram which is constructed on the basis of a classical nonlinear mechanical model of machine tool chatter vibration. With varying amplitude ratio and frequency ,sinusoidal spindle speed variation (S3V) cutting process is investigated in time domain, which tests and verifies the feasibility of chatter suppression by S3V method.
Cutting Force, Cutting Temperature and Tool Wear in End Milling of Powder Metallurgy Nickel-Based Superalloy FGH95
Authors: Du J. , Liu Zhan Qiang
Published: March 2011

FGH95 is one kind of high-strength, thermal-resistant nickel-based superalloys fabricated by powder metallurgy (PM). It plays an increasingly important role in the development and manufacture of turbine discs. Due to the extreme toughness and work hardening characteristics of this kind of superalloy, the problem of machining FGH95 is one of ever-increasing magnitudes. This paper investigates the influence of cutting parameters on the cutting force, cutting temperature and tool wear during the end milling of PM nickel-based superalloy FGH95. The empirical formula for cutting force and cutting temperature of FGH95 are given out. Experimental results show that the cutting speed among milling parameters has the greatest influence on cutting forces and cutting temperatures. It is shown that the major tool wear mechanisms are combination interactions of abrasive wear, adhesion wear, micro-breakout and chipping.
Finite Element Analysis and Calculation of Load Capacity on Aerostatic Thrust Bearing
Authors: Shu P.C. , Xiao S.H. , Wu H.
Published: March 2011

For the design and application of ultra-high speed aerostatic spindle, it is often difficult to determine the load capacity of bearing gas film because of nonlinear problem, especially when the gas film is very thin. As ultra-high speed aerostatic spindle is working, rotational velocity of spindle ranges up to 300,000 rpm, while Reynolds number of air flow also increases in aerostatic bearing, so we need to consider the impact of gas inertia on the load capacity. In order to improve design accuracy of ultra-high speed aerostatic spindle, it is vitally necessary to consider hydrodynamic effect of aerostatic bearings. By using finite element analysis software ANSYS software as analysis platform, through finite element the analysis of the internal flow field of aerostatic thrust bearing, this paper obtains the relationship of rotation speed and load capacity of aerostatic thrust bearing.
Finite Element Simulation of Heavy Cutting Process
Authors: Yue Cai Xu , Liu Xian Li , Zhao Zhong Yang , Li K.Q. , Ma T.Y.
Published: March 2011

As heavy cutting is widely used in the energy field of China, it has important significance to study the cutting mechanism. Based on this reason, this paper has overcome limitations of the traditional cutting method, established a reasonable boundary conditions by using finite element analysis software Third Wave, and used accurate material constitutive model to build finite element simulation model on heavy cutting process, The effect of the cutting parameters to the cutting process is studied by simulation results, and chip formation is analyzed. The results provide a theoretical basis for the optimization on heavy cutting conditions.
Study on the Machinability Characteristics of Superalloy K424 during High Speed Turning
Authors: Xiao M.H. , He N. , Li L. , Qiu B.G. , Su Y.
Published: March 2011

The present paper is an attempt of an experimental investigation on the machinability of superalloy, K424 during high speed turning using different ceramic inserts under different cutting speed and cooling/lubricating condition. The effect of machining parameters on the tool wear was examined through SEM micrographs.The experimental results show that, round Al2O3＋SiCW KY4300R ceramic insert shows the best cutting performance in cutting the superalloy K424 , and it should be used in rather higher speed. Cold nitrogen gas is not recommended when machining nickel-based alloy with ceramic tools. SEM and EDS analysis shows that the ceramic tool was severely controlled by tool nose and depth-of-cut notch wear, followed by flaking and chipping.
Design and Simulation of Ground Test Platform for Microsatellite Docking Mechanism
Authors: Lai Yi Nan , Zhao M.J. , Dai Y. , Lai M.Z. , Lai X.
Published: March 2011

According to the requirements of the ground demonstration test for small-sized docking mechanism, a set of ground test platform was designed, which can simulate the weightless environment of space and provide six degrees of freedom for the docking mechanism. This paper elaborated the structure and working process of the test platform, and used the way of rigid-flexible coupling to analysis the test platform in dynamics simulation by ADAMS. The mechanical properties of the platform’s key parts during the collision process were obtained
Application of Continuous Wavelet Features and Multi-Class Sphere SVM to Chatter Prediction
Authors: Wu Shi , Jia D.K. , Liu X.L. , Yan F.G. , Li Y.F.
Published: March 2011

A cutting chatter forecast method based on continuous wavelet feature and multi-class spherical Support Vector Machines is studied in this paper. The method based on continuous wavelet transform extracts the cutting vibration signal feature and uses multi-class spherical Support Vector Machines to discern the chatter. In order to simplify computational complexity when binary classification SVM turn to multi-class classification, the algorithm makes every kind of samples have a spherical SVM. In the feature space identified the test sample and spherical SVM centre distance as a decision-making function. Experiments show that using combine spherical SVM with continuous wavelet feature Vector has good recognition effect in the milling chatter recognition system. Chatter inoculation forecast accuracy reaches 95%, and chatter outbreak forecast accuracy reaches 97.5%.
Modeling and Predicting Cutting Force in Precision Hard Turning
Authors: Chen Tao , Yan F.G. , Hu J.S. , Ding Yun Peng , Han H.Y.
Published: March 2011

This paper proposes a new approach to modeling the cutting force, based on friction behavior on tool-chip interface in precision hard turning. The modeling touches on such researches as into experimental relationship between cutting force and cutting load on tool-chip friction interface, equivalent transformation of radius cutting edge, transformation between orthogonal cutting and 3D cutting, and calculating cutting force coefficient. The model has realized the transformation from orthogonal cutting to oblique cutting, then to 3D cutting, which can make calculation results of all parameters in orthogonal cutting model transplant into complex 3D cutting. The experiments indicate accuracy and effectiveness of the cutting force prediction model
The Impeller Five-Axis NC Machining Simulation Based on UG NX 7.5
Authors: Huang J.C. , Liu Xian Li , Jia D.K. , Li W.D. , Guo K.
Published: March 2011

To improve the processing efficiency and Surface qualityof impeller. Impeller processing difficulties as a major object of study were researched by this paper. Using UG7.5 impeller processing module, Based on the impeller feature division idea and to optimize the impeller machining path.Finally, Through it carried out the tool path generation and simulation and verify the feasibility of processing. To effectively enhance programming efficiency and processing quality.
Vibration Modeling and Analysis of Large Thin-Walled Cylinder Workpiece in Turning Ring Groove of Inner Hole
Authors: Zhang Ji Jun , Liu Xian Li , Zhai Yuan Sheng , He G.H. , Zhang J.L.
Published: March 2011

The chatter between tool and workpiece has become a problem that urgently need to be solved in modern manufacturing system development.This paper analyzes the main factors in affecting the flutter when to turn ring groove of inner hole for large stainless steel thin-walled pieces. take normal direction of workpiece cutting surface as modeling direction, consider processing status of the large cylinder workpiece with large diameter, large height, small wall thickness and vertical large overhang. Based on vibration theory, establish a vibration dynamic mathematical model for large thin-walled parts in turning process, investigate the flutter in processing, provide a useful reference for solving the vibration problem of large cylinder parts in processing.
Establishing of Constitutive Equation of ZGMn13 Steel and Cutting Simulation Test
Authors: Xu Li , Teng Tao , Yang L. , Fan Jia
Published: March 2011

Constitutive equation of material has an important influence on the simulation results in the finite element simulation. In this paper, Johnson-Cook constitutive equation parameters of the high manganese steel ZGMn13 have been derived from the data of compression tests and split Hopkinson pressure bar test. Based on this equation, the finite element simulation of ZGMn13 steel cutting has been done. This Johnson-Cook constitutive model of high manganese steel ZGMn13 can accurately describe the plastic behavior of the material.
The Mechanical Behavior of Carbon Steel in the Super High-Speed Cutting State
Authors: Zhang Zhi Jun , Li J.Q. , Huang Shu Tao
Published: March 2011

From the research of the mechanical behavior of the carbon steel in the super high-speed cutting state and then obtaining the microstructure in the different super high-speed cutting state, the cutting mechanism of the carbon steel in the super high-speed cutting process is explored. And from the interaction between the strain-stress and the strain-temperature, the mechanical behavior of the carbon steel in the high-speed cutting state and the cutting mechanism in the super high-speed state effected by the mechanical behavior are explored.
The Analysis of Saw-Tooth Chip Formation in High Speed Machining through Material Micro-Hardness Measurement
Authors: Su Guo Sheng , Liu Zhan Qiang
Published: March 2011

The material micro-hardness is used to reflect the plastic deformation within the localized shear band and the segment of saw-tooth chip. A high strength alloy steel Aermet 100 is taken as the workpiece material. The saw-tooth chip roots are obtained by cutting operation. The material micro-harnesses along the shortly initiated localized shear band, across the shortly initiated localized shear band and fully developed localized shear band, and within the segment are examined and analyzed. The localized shear band initiation and propagation are revealed by a new proposed model. The results show the localized shear band initiates firstly at the tool tip end of the primary shear band, and consequently another localized shear nucleates at the free surface end of the primary shear band. These two localized shears propagate face to face until the whole localized shear band is formed.
Comparison Research on the Structural Elements of Two Business Models with the Different Performance Level
Authors: Hu Bao Liang
Published: March 2011

This paper identifies structural element differences between the business model(BM) with relatively high-level performance and BM with relatively low-level performance through comparison of two cases of the BM with relatively high-level performance and two cases of the BM with relatively low-level performance in terms of ten aspects such as cost structure, revenue mechanism, value proposition, target market, competitive strategy, value configuration, value network, entrepreneur team, capital structure and core competence.
Operational-Mission-Oriented Method for Equipment Support Resource Verification
Authors: Chen Le , Yu Yong Li , Shu Zheng Ping , Li Dong Dong , Li Yuan
Published: March 2011

With elaborating the research evolvement of equipment support resource verification, this paper demonstrated the significance of operational mission to this research. It decomposed Equipment Support System (ESS) into three subsystems: operational mission system, support object system and support resources system. According to the theories of Integrated Logistics Support, the overall parameter model was established to depict the relationship and impact mechanism of ESS’s components. Focusing on the key parameter: mean logistic delay time (MLDT), this paper proposed a transformation model to convert operational mission requirements to equipment support requirements.Transformation model can predict and ascertain all support resources needed to accomplish operational mission scientifically.