bluuebunny/crossref_metadata_2025 huggingface dataset:
Meropenem‐Induced Vanishing Bile Duct Syndrome
Authors: Schumaker Annabel L. , Okulicz Jason F.
Published: March 2011

Vanishing bile duct syndrome (VBDS) is a rare and potentially life‐threatening disorder in which progressive destruction and disappearance of small intrahepatic bile ducts occur, with resultant cholestasis. The mechanism by which biliary epithelial cells are damaged and intrahepatic bile ducts are lost has not been fully elucidated. However, many etiologies have been reported, and several drugs have been implicated. Meropenem is a widely used, well‐tolerated broad‐spectrum carbapenem antibiotic indicated for the treatment of intraabdominal infections, complicated skin and skin structure infections, and pediatric bacterial meningitis. We describe what we believe is the first reported case of meropenem‐induced VBDS. A 60–year‐old woman was diagnosed with VBDS after being treated with meropenem for a left temporal lobe brain abscess. Three weeks after starting the drug, the patient developed mixed hepatocellular and cholestatic liver injury with jaundice and pruritus. Meropenem‐induced liver injury was suspected, and the drug was discontinued. Diagnostic tests ruled out other causes of cholestasis, including infectious and immunologic conditions. A liver biopsy, performed due to persistent liver injury, demonstrated an absence of bile ducts, which, in conjunction with the patient's clinical course, was consistent with the diagnosis of VBDS. Several months after the cessation of meropenem, the patient's liver function test results improved. Use of the Naranjo adverse drug reaction probability scale indicated a probable relationship (score of 6) between the patient's development of VBDS and meropenem therapy. A high index of suspicion is necessary to diagnose VBDS and other types of drug‐induced liver injury. Clinicians should consider VBDS as a potential diagnosis in patients receiving meropenem who have prolonged cholestasis, especially after other more probable causes have been excluded.
The SAFE index: using a threshold population target to measure relative species threat
Authors: Clements Gopalasamy Reuben , Bradshaw Corey JA , Brook Barry W , Laurance William F
Published: March 2011

The International Union for Conservation of Nature (IUCN) Red List is arguably the most popular measure of relative species threat, but its threat categories can be ambiguous (eg “Endangered” versus “Vulnerable”) and subjective, have weak quantification, and do not convey the threat status of species in relation to a minimum viable population target. We propose a heuristic measure that describes a “species' ability to forestall extinction”, or the SAFE index. We compare the abilities of the SAFE index with those of another numerically explicit metric – percentage range loss – to predict IUCN threat categories using binary and ordinal logistic regression. Generalized linear models showed that the SAFE index was a better predictor of IUCN threat categories than was percentage range loss. We therefore advocate use of the SAFE index, possibly in conjunction with IUCN threat categories, because the former indicates the “distance from extinction” of a species, while implicitly incorporating population viability as a variable.
Lateral Clavicular Autograft for Repair of Reverse Hill-Sachs Defect
Authors: Shenoy Ravikiran , Kamineni Srinath
Published: March 2011

Posterior dislocations of the shoulder joint can result in an impression fracture over the anteromedial humeral head, termed the reverse Hill-Sachs lesion, the presence of which can contribute to recurrent dislocations. Methods described to repair this defect include using allografts, iliac crest and coracoid process autografts, and bone graft substitutes. We describe a novel technique using the lateral end of the ipsilateral clavicle as an autograft in a 78 year old man with a reverse Hill Sachs lesion. This graft can be harvested through the same incision and does not compromise the stability of the acromioclavicular joint or any future shoulder arthroplasty.
Effect of a Direct Thrombin Inhibitor Compared with Dalteparin and Unfractionated Heparin on Human Osteoblasts
Authors: Winkler Tobias , Perka Carsten , Matziolis Dörte , Matziolis Georg
Published: March 2011

Purpose:

Osteoporosis is a relevant problem after long term administration of unfractionated heparin (UFH) and low molecular weight heparin. Melagatran is a representative of a new group of direct thrombin inhibitors with comparable data in the prevention of thromboembolic events after orthopaedic surgery. The aim of ourin vitrostudy was to investigate the effect of a direct thrombin inhibitor compared with dalteparin and UFH on human osteoblasts.

Materials and Methods:

Melagatran, dalteparin and UFH were added to primary osteoblast cultures in their therapeutic range and two decimal powers below and above. Cell number, protein synthesis, mitochondrial and alkaline phosphatase activity and collagen type I synthesis were evaluated.

Results:

Melagatran showed the least influence on protein synthesis and cell proliferation with a reduction of cell number to 83.5 ± 9% (p = 0.027) of the control group only in the highest investigated concentration after 15 days of incubation.

Mitochondrial and alkaline phosphatase activity and collagen type I synthesis in osteoblasts incubated with melagatran and dalteparin showed similar patterns. UFH showed the most pronounced influence on cellular metabolism.

Conclusions:

Melagatran showed less inhibitory in vitro effects on human osteoblasts than dalteparin or UFH. The presented study gives first hints that direct thrombin inhibitors may help prevent heparin-induced negative effects on bone metabolism.
Comparing Functional Outcome of Triangle Tilt Surgery Performed Before Versus After Two Years of Age
Authors: Nath Rahul K , Somasundaram Chandra , Mahmooduddin Faiz
Published: March 2011

Background:

Many patients each year who are born with obstetric brachial plexus injuries eventually do not achieve complete recovery. As a result of the primary nerve injuries, these patients will often develop bony deformities involving the shoulder joint as a secondary consequence. The triangle tilt surgery has been shown to be an effective procedure to correct these deformities and has been performed on patients ranging in age from less than a year old to adolescence. The purpose of this retrospective study is to compare outcomes of triangle tilt surgery performed on patients before the age of 2 years versus after 2 years of age to determine an optimal age to operate on these children.

Methods:

36 patients with deformities developed secondarily from the initial obstetric brachial plexus injury in this study were divided into 2 groups. Group 1, those who had undergone triangle tilt surgery at < 2 yrs of age (16 patients). Group 2, those who were operated at > 2 yrs of age (20 patients). Group 1 age range: 9 months to 23 months, average: 18 months. Group 2 age range: 26 months to 9 years, average: 6 years.

Results:

Significant differences were found between the 2 groups (0-2 yrs vs > 2yrs) in regards to overall changes (pre- to post-op) in Mallet score, external rotation score, hand-to-mouth score, and supination angle.

Discussion:

This study demonstrates that triangle tilt surgery had better outcomes on clinical functioning if performed before the age of 2 years, however, improvement in clinical functioning can still be achieved if the triangle tilt surgery is performed after the age of 2 years as well. A possible mechanism to explain this phenomenon is the increased potential for anatomical remodeling if the triangle tilt surgery is performed at a younger age, thereby leading to significant functional improvement.
Pain Behavior Changes Following Disc Puncture Relate to Nucleus Pulposus Rather than to the Disc Injury Per Se: An Experimental Study in Rats
Authors: Nilsson Elin , Nakamae Toshio , Olmarker Kjell
Published: March 2011

It has previously been demonstrated that disc puncture in the rat induced changes in grooming and wet dog shakes, two behavioral changes that may be linked to discomfort and neuropathic pain. In this study the aim was to separate the effects of disc injury and the epidural presence of nucleus pulposus. Following anesthesia, the L4-5 disc was exposed using a dorsal approach. Ten rats received a superficial disc injury without nucleus pulposus leakage and ten rats received nucleus pulposus from a donor rat without disc injury. In ten animals the L4-5 disc was punctured using a ventral approach, with 10 corresponding controls. Spontaneous behavior was assessed after surgery. The data was matched to historical control of dorsal sham surgery and disc puncture. The study showed that the effects of nucleus pulposus were more pronounced than the effects induced by the disc injury. Ventral disc puncture did not induce any behavioral changes different from sham exposure. In conclusion, the data from the study indicate that behavioral changes induced by disc puncture are more likely to relate to the epidural presence of nucleus pulposus than the disc injury per se.
Epidemiology of Knee and Hip Arthroplasty: A Systematic Review§
Authors: Singh Jasvinder A
Published: March 2011

We present a systematic review of epidemiologic studies of Total Knee Arthroplasty (TKA) and Total Hip Arthroplasty (THA). The studies summarized in this systematic review provide us with estimates of arthroplasty utilization rates, underlying disease frequency and its trends and differences in utilization rates by age, gender and ethnicity among other factors. Among these, many studies are registry-based that assessed utilization rates using data from major orthopedic centers that may provide some understanding of underlying diagnosis and possibly time-trends. Several studies are population-based cross-sectional, which provide estimates of prevalence of TKA and THA. Population-based cohort studies included in this review provide the best estimates of incidence and utilization rates, time-trends and differences in these rates by important patient characteristics (age, gender, ethnicity and others). This article reviews the current published literature in the area and highlights the main findings.
Diagnosis and Management of Infected Total Knee Arthroplasty§
Authors: Kalore Niraj V , Gioe Terence J , Singh Jasvinder A
Published: March 2011

Infection following total knee arthroplasty can be difficult to diagnose and treat. Diagnosis is multifactorial and relies on the clinical picture, radiographs, bone scans, serologic tests, synovial fluid examination, intra-operative culture and histology. Newer techniques including ultrasonication and molecular diagnostic studies are playing an expanded role. Two-stage exchange arthroplasty with antibiotic cement and 4-6 weeks of intravenous antibiotic treatment remains the most successful intervention for infection eradication. There is no consensus on the optimum type of interval antibiotic cement spacer. There is a limited role for irrigation and debridement, direct one-stage exchange, chronic antibiotic suppression and salvage procedures like arthrodesis and amputation. We examine the literature on each of the diagnostic modalities and treatment options in brief and explain their current significance.
Total Shoulder Arthroplasty
Authors: Sanchez-Sotelo Joaquin
Published: March 2011

Shoulder arthroplasty has been the subject of marked advances over the last few years. Modern implants provide a wide range of options, including resurfacing of the humeral head, anatomic hemiarthroplasty, total shoulder arthroplasty, reverse shoulder arthroplasty and trauma-specific implants for fractures and nonunions. Most humeral components achieve successful long-term fixation without bone cement. Cemented all-polyethylene glenoid components remain the standard for anatomic total shoulder arthroplasty. The results of shoulder arthroplasty vary depending on the underlying diagnosis, the condition of the soft-tissues, and the type of reconstruction. Total shoulder arthroplasty seems to provide the best outcome for patients with osteoarthritis and inflammatory arthropathy. The outcome of hemiarthroplasty for proximal humerus fractures is somewhat unpredictable, though it seems to have improved with the use of fracture-specific designs, more attention to tuberosity repair, and the selective use of reverse arthroplasty, as well as a shift in indications towards internal fixation. Reverse shoulder arthroplasty has become extremely popular for patients with cuff-tear arthropathy, and its indications have been expanded to the field of revision surgery. Overall, shoulder arthroplasty is a very successful procedure with predictable pain relief and substantial improvements in motion and function.
Simple and improved regioselective brominations of aromatic compounds using N-benzyl N,N-dimethyl anilinium peroxodisulfate in the presence of potassium bromide under mild reactions conditions
Authors: Ghasemnejad-Bosra Hassan , Ramzanian-Lehmali Frhad , Jafari Somaye
Published: March 2011

A simple, efficient, and mild method for the selective bromination of some
activated aromatic compounds using N-benzyl N,N dimethyl anilinium
peroxodisulfate in the presence of potassium bromide in non-aqueous solution
is reported. The results obtained revealed good to excellent selectivity
between the ortho and para positions of phenols and methoxyarenes.
Engineering intelligent systems on the knowledge formalization continuum
Authors: Baumeister Joachim , Reutelshoefer Jochen , Puppe Frank
Published: March 2011

Engineering intelligent systems on the knowledge formalization continuum

In spite of their industrial success, the development of intelligent systems is still a complex and risky task. When building intelligent systems, we see that domain knowledge is often present at different levels of formalization—ranging from text documents to explicit rules. In this paper, we describe the knowledge formalization continuum as a metaphor to help domain specialists during the knowledge acquisition phase. To make use of the knowledge formalization continuum, the agile use of knowledge representations within a knowledge engineering project is proposed, as well as transitions between the different representations, when required. We show that a semantic wiki is a flexible tool for engineering knowledge on the knowledge formalization continuum. Case studies are taken from one industrial and one academic project, and they illustrate the applicability and benefits of semantic wikis in combination with the knowledge formalization continuum.
Defining the semantics of rule-based Web applications through model-driven development
Authors: Cañadas Joaquín , Palma José , Túnez Samuel
Published: March 2011

Defining the semantics of rule-based Web applications through model-driven development

Rule languages and inference engines incorporate reasoning capabilities to Web information systems. This paper presents an approach for the specification and development of Web applications performing the usual functionalities of data management and incorporating a rule engine for reasoning capabilities. The proposed approach is based on the definition of a high-level representation of the semantics of rule-based applications through a formalism for conceptual modeling combining lightweight ontologies and production rules. These models are used as the source for a model-driven method that applies several transformations to conceptual models generating the rule-based Web application code in an automatic process. As a result, the rule-based Web application embeds a rule engine suitable for deducing information by applying an inference process. The structure of the information managed by the Web application is based on ontology classes, whereas the logical expressions applied in reasoning are obtained from production rules of the model. A rule-based Web application has been developed and evaluated using a supporting tool that implements the ideas presented in this paper.
A method for learning scenario determination and modification in intelligent tutoring systems
Authors: Kozierkiewicz-Hetmańska Adrianna , Nguyen Ngoc
Published: March 2011

A method for learning scenario determination and modification in intelligent tutoring systems

Computers have been employed in education for years. They help to provide educational aids using multimedia forms such as films, pictures, interactive tasks in the learning process, automated testing, etc. In this paper, a concept of an intelligent e-learning system will be proposed. The main purpose of this system is to teach effectively by providing an optimal learning path in each step of the educational process. The determination of a suitable learning path depends on the student's preferences, learning styles, personal features, interests and knowledge state. Therefore, the system has to collect information about the student, which is done during the registration process. A user is classified into a group of students who are similar to him/her. Using information about final successful scenarios of students who belong to the same class as the new student, the system determines an opening learning scenario. The opening learning scenario is the first learning scenario proposed to a student after registering in an intelligent e-learning system. After each lesson, the system tries to evaluate the student's knowledge. If the student has a problem with achieving an assumed score in a test, this means that the opening learning scenario is not adequate for this user. In our concept, for this case an intelligent e-learning system offers a modification of the opening learning scenario using data gathered during the functioning of the system and based on a Bayesian network. In this paper, an algorithm of scenario determination (named ADOLS) and a procedure for modifying the learning scenario AMLS with auxiliary definitions are presented. Preliminary results of an experiment conducted in a prototype of the described system are also described.
System matrix computation for iterative reconstruction algorithms in SPECT based on direct measurements
Authors: Borys Damian , Szczucka-Borys Katarzyna , Gorczewski Kamil
Published: March 2011

System matrix computation for iterative reconstruction algorithms in SPECT based on direct measurements

A method for system matrix calculation in the case of iterative reconstruction algorithms in SPECT was implemented and tested. Due to a complex mathematical description of the geometry of the detector set-up, we developed a method for system matrix computation that is based on direct measurements of the detector response. In this approach, the influence of the acquisition equipment on the image formation is measured directly. The objective was to obtain the best quality of reconstructed images with respect to specified measures. This is indispensable in order to be able to perform reliable quantitative analysis of SPECT images. It is also especially important in non-hybrid gamma cameras, where not all physical processes that disturb image acquisition can be easily corrected. Two experiments with an 131I point source placed at different distances from the detector plane were performed allowing the detector response to be acquired as a function of the point source distance. An analytical Gaussian function was fitted to the acquired data in both the one- and the two-dimensional case. A cylindrical phantom filled with a water solution of 131I containing a region of "cold" spheres as well as a uniform solution (without any spheres) was used to perform algorithm evaluation. The reconstructed images obtained by using four different of methods system matrix computation were compared with those achieved using reconstruction software implemented in the gamma camera. The contrast of the spheres and uniformity were compared for each reconstruction result and also with the ranges of those values formulated by the AAPM (American Association of Physicists in Medicine). The results show that the implementation of the OSEM (Ordered Subsets Expectation Maximization) algorithm with a one-dimensional fit to the Gaussian CDR (Collimator-Detector Response) function provides the best results in terms of adopted measures. However, the fit of the two-dimensional function also gives satisfactory results. Furthermore, the CDR function has the potential to be applied to a fully 3D OSEM implementation. The lack of the CDR in system matrix calculation results in a very noisy image that cannot be used for diagnostic purposes.
A concept of drive and control system of a novel device for people evacuating from large passenger ships
Authors: Dymarski Czesław
Published: March 2011

A concept of drive and control system of a novel device for people evacuating from large passenger ships

Year-after-year increasing number and size of sea-going passenger ships make it necessary to search for novel methods of evacuation of passengers from such large objects or to improve those which have been applied so far. This paper presents a concept of one of the original methods, in which, a.o., chain lifts have been applied to hold up life boats during voyage as well as to launch them in case of evacuation. Technical assumptions and requirements as well as schematic diagram of the hydraulic drive and control system of the lift, is presented.
Analysis of fracture toughness of modified timber
Authors: Kyzioł Lesław
Published: March 2011

Analysis of fracture toughness of modified timber

This paper presents results of fracture toughness tests on DCB specimens made of natural and modified pine wood. The energy release coefficients Ga were calculated for both the materials under TL and RL crack propagation modes and the 1st mode of loading. Relations between the energy release coeffcients GaI and the stress intensity factors KaI have been determined. The obtained test results are presented in the form of tables and diagrams.
Dutiful Daughters and Colonial Discourse in Jane West's A Gossip's Story
Authors: Rehbein Angela
Published: March 2011

In A Gossip's Story and a Legendary Tale (1796), Jane West engages with both the contemporary ideology and the political reality of the British empire by explicitly supporting British overseas trade while acknowledging the precarious nature of a transatlantic empire. For West, the female body is a potent site through which to explore colonialist ideologies. The fates of various female characters reinforce ideas about feminine virtue and sexual regulation shaped by British contact with the Atlantic world, thus promoting a moral code that would come to define the empire. If young women do represent the British subject in didactic fiction of this period, with the father figure representing state authority, West's portrayal of these characters in A Gossip's Story against the backdrop of British Caribbean colonies alters our understanding of the national culture she promotes. A Gossip's Story's overt message —the importance of filial duty—urges its female readers not just to be good daughters, but to be good daughters of the British empire.
Pierre Brunet, patriote durtalois (1753-1799)
Authors: Chereau Claude
Published: March 2011

Pierre Brunet, born in the family ofa tile maker in Durtal (north of Anjou ), is a typical republican countryman. His eight children died very young and himself, an ordinary craftsman, was early in financial difficulties. Assuming responsabilities in the organisation of the commune of Durtal, then in the national guard and in the local political club, he hounded the royalists down continually from 1793 to 1796. The «chouans» tempted many times to murder him and they succeeded at the end of the Directoire. His fellow citizens, who needed hom to protect them, did not defend him too much.
Ns3 Protease of Genotype 3 Subtype H HCV Identified in Southeastern France
Authors: Colson Philippe , Gayet Stéphane , Gerolami René
Published: March 2011

HCV displays considerable levels of nucleotide and amino acid diversity. Recently, the relevance of natural polymorphisms in worldwide isolates has been addressed in view of future protease inhibitor (PI)-based treatments; genotype- and subtype-specific natural polymorphisms within HCV NS3 protease were identified at amino acid sites associated either with resistance to PIs or with compensatory mutations. Here, we describe a case of chronic infection with HCV of genotype 3 subtype h (HCV-3h), formerly only described from three patients originating from Somalia, and we provide the first NS3 protease sequence for such strains. NS3 protease sequences of HCV-3h recovered in the present study harbour specific amino acid residues not encountered in other reference HCV genotypes and subtypes at nine of the 181 NS3 protease positions; none of these amino acids are known to confer resistance to PIs. Of note, 5’ untranslated region sequence-based genotyping classifies them into genotype 1.
Critical Thickness and Dynamic Stiffness for Chatter Avoidance in Thin Floors Milling
Authors: Campa Francisco Javier , López de Lacalle Luis Norberto , Urbicain Gorka , Lamikiz Aitzol , Seguy Sébastien , Arnaud Lionel
Published: March 2011

A common problem in the aeronautical industry is the chatter vibration due to the lack of dynamic stiffness in the milling of thin walls and thin floors. The present work proposes a method for chatter avoidance in the milling of flexible thin floors with a bull nose end mill. It allows the calculation of the thickness previous to finish milling or the minimum dynamic stiffness that the floor must have to avoid the chatter vibration appearance. To obtain these values, the stability model algorithm has been inverted to estimate the thickness or the dynamic stiffness required in a floor to allow a stable milling. This methodology has been validated satisfactorily in several experimental tests.
Cutting Performances of Diamond Coated Milling Tools in Machining Aluminum Alloy
Authors: Wang Liang , Zhang Jian Guo , Shen Bin , Sun Fang Hong
Published: March 2011

CVD diamond films are deposited on cobalt cemented tungsten carbide (WC-Co) endmills using hot filament chemical vapor deposition (HFCVD) method. Scanning electron microscope (SEM) and Raman spectroscopy are used to characterize the as-deposited diamond films. To evaluate the cutting performances of as-fabricated CVD diamond coated endmills, dry milling tests are conducted using aluminum alloy as the workpiece material. The uncoated WC-Co endmills are also adopted in the milling tests for the sake of comparability. The experimental results show that the build-up edge formed on the uncoated WC-Co endmills at very early stage of the cutting tests. Comparatively, CVD diamond coated endmills present an excellent anti-adhering property. The result suggests that depositing diamond coating on WC-Co endmills is a viable way to improve their cutting performances in machining of aluminum alloy materials
Cluster Analysis on Vibration Characteristic in High Speed Ball-End Milling Hardened Steel
Authors: Jiang Bin , Yang S.C. , Yang Yin Jin , Zheng Min Li , Sun P.
Published: March 2011

Aim at the uncertainty of vibration behavior in high speed ball-end milling hardened steel, carried out the experiment of high speed milling hardened steel and modal analysis of cutter, studied vibration behavior of cutter and workpiece, and established vibration behavior sequence of high speed milling hardened steel. Using gray system theory, did gray cluster analysis of vibration characteristics, explored the correlation among cutter vibration, workpiece vibration and surface roughness characteristics, put forward the method of characterizing vibration characteristics in high speed ball-end milling hardened steel. The results show that high frequency vibrations of cutter and workpiece are caused by the interaction of centrifugal and dynamic cutting force, the increase of cutter overhang enhances high frequency vibration of cutter, the characteristic of cutter vibration changes from low frequency vibration to interaction of low frequency vibration and high frequency vibration. Using cutters with different overhang, surface roughness of high speed milling hardened steel has similar characteristics, surface roughness in row spacing direction can characterize low frequency vibration of cutter, and surface roughness in feed can characterize resonance characteristic of cutter caused by high frequency vibrations of cutter and workpiece.
Cutting Force Model Prediction Considering Cutting Edge Parameters Base on Genetic Algorithm
Authors: Wang Yu , Wang L.Q. , Li Y.F. , Zhai Yuan Sheng , Liu X.L.
Published: March 2011

During precise hard cutting, back cutting depth and feed rate are relatively small. Study on the influence of PCBN (Polycrystalline Cubic Boron Nitride) cutting tools edge (chamfer edge or cutting edge radius) on cutting force is important. As the effect of cutting edge on mechanism of shear slip plane is very complicated, so to study the effect of consider cutting edge parameters and cutting parameters by genetic algorithm on cutting force, to build up cutting force model of precise hard cutting. It is feasible to predict cutting force by genetic algorithm with experiment.
Experimental Study of Titanium Alloy Micro-Holes by EDM Fuzzy Control System
Authors: Wang Yu Kui , Geng X.S. , Wang Zhen Long , Shan D.B.
Published: March 2011

Aiming at machining deep micro-holes in titanium alloy, an experimental approach for EDM adopted a fuzzy control system was introduced. The fuzzy control system based on statistics of discharge states, that pulse interval and jumping height as control parameters, was self-developed. The suitable parameter for the deep micro-hole EDM process can be handily adjusted and modified in visual MATLAB fuzzy editor. A lot of experiments for titanium alloy micro-hole machining were performed on the EDM machine tool adopting the fuzzy control system. A titanium alloy deep micro-hole with 80μm in diameter and 15 in the ratio of depth-diameter is obtained. The process and results of experiments show that the process stability and efficiency be improved; due to the fuzzy control system and its suitable control parameters are applied.
Analysis of Elastic Deformation of Axial Foil Hydrodynamic Thrust Bearing Used in Turbine Generator
Authors: Wang Yu Kui , Zeng Z.Q. , Wang Zhen Long , Huang Y.S.
Published: March 2011

In this paper, an elastic deformation of the axial foil hydrodynamic thrust bearing used in 100KW gas turbine generator is studied. The finite element model of the foil hydrodynamic thrust bearing was established using Solidworks and ANSYS. The foil hydrodynamic thrust bearing which considered foil deformation was analyzed and calculated based on the results of the approximate calculation. The FEA model considered the interaction of plane foil deformation and wave foil. The wave foil was not hypothesized as the linear distributed spring when set up the finite element model. The ANSYS results have demonstrated that the deformation of foil bearing designed based on the result of numerical calculation can meet the requirement of minimal film thickness of bearing lubricant layer.
A Steel Plate Correction Method of NC Flame Cutting Based on Edge Detection
Authors: Jiang Y.C. , Wang J.F. , Zhang L.J. , Huang B.S.
Published: March 2011

In order to overcome the low efficiency and precision disadvantages of steel plate position manual correction in the NC(numerical control) Flame Cutting, a high efficient steel plate position correction method is proposed by detecting the edge of steel plate images. Based on the development environment of OpenCV, the video of steel plate is captured based on the DirectShow Technology and the edge linear equation of steel plate is obtained by detecting the steel plate image edge with Canny algorithm and the angle between the equation and the x axis is obtained. The steel plate correction algorithm is designed, and based on the deviation angle of the steel plate, and rotation transformation of related processing images, the steel plate corrections is conducted automatically. The experimental testing of steel plate correction is done and the results show that the method can well done the steel plate correction and the error lower than 0.3 degree and can satisfy the flame cutting process requirement and have a great theory and economic value.
Research on Thermodynamic Characteristics in High-Speed Machining System
Authors: Wan Yi , Liu Zhan Qiang , Ai Xing , Wu Z.X.
Published: March 2011

High-speed machining is investigated in a new viewpoint, thermodynamic theory. Many phenomena in cutting, such as heat conduction, chemical reaction, diffusion and so on, can be studied with thermodynamic theory. In this paper, entropy generation and entropy flow in cutting system are revealed as well as the interaction of sub processes. As a case study, the oxidation of cemented carbide tool was studied in thermodynamic theory and experiments. The results show that thermodynamic theory is effective.
Analytical Method for Softness Abrasive Flow Field Based on Low Reynolds K-ε Model
Authors: Yuan Qiao Ling , Ji Shi Ming , Tan Da Peng , Zhang Li
Published: March 2011

As it was difficult to solve the near wall characteristics of flow field in softness abrasive flow machining (SAFM) on mould structural surface, a method for simulation the flow characteristics based on the low Re number k-ε model was proposed in this paper. The U-shaped tube was used as specific simulation object. The motion law of particles and related parameters were calculated and the precision machining mechanism of SAFM was discussed. Simulation results show that the micro cutting of abrasive flow mainly appears as the transposition of cutting location influenced by the particle pressure, and as the variation of machining efficiency influenced by near-wall particle velocity. Thus via control of the inlet velocity and its corresponding machining time, it is supposed to work out the machining process according with the machining requirements. By tracking near-wall particles, it can be confirm that the movement of near-wall abrasive particles is similar to stream-wise vortices. The cutting traces on workpiece surfaces assume disorderly arrangement, so the feasibility of SAFM method can be reaffirmed.
Control Algorithm Study for some Optical Tracking Measurement System with Low Mechanical Resonance Frequency
Authors: Bi Yong Li , Wang Zhong Xian
Published: March 2011

For some optical tracking measurement systems, because their size, weight and space structure are very strict restrictions, DC servo motors have to drive the loads through the several stages of gear transmission. For such a nonlinear controlled object, it is difficult to obtain acceptable control performance applying the traditional controller design method. In the paper, firstly, establish such a non-linear system dynamic model, and consider intelligent control algorithm to inhibit mechanical resonance effect for the control system performance. In order to achieve real-time control easily, the paper suggests a fuzzy numeric model with the self-regulating factor based on analytic expression for such a non-linear system. The result demonstrates that the fuzzy controller is very effective in applications. This work provides a new thought for a controller design to inhibit the low mechanical resonance frequency.
Stability Research on High Speed Milling of Aviation Aluminum Alloy
Authors: Guo Yan Yan , He Wan Tao , Zhao Can
Published: March 2011

The stability of cutting system is an important research in high-speed machining area. It is widely used in engineering practice. First, this paper studies the milling forces and their change law when milling aluminum alloy through orthogonal experiment. And it solves the milling coefficients. Second, it modal parameters of milling system such as natural frequency, modal mass and equivalent stiffness by hammer experiment. On this basis, it draws the stability lobe about the spindle speed and radial depth of cut and verifies the accuracy of the stability lobe.
Fuzzy Comprehensive Evaluation of Aluminum Alloy 7475 High-Speed Milling Parameter Optimization
Authors: Lin Ai Qin , Zheng Min Li , Gu Yan , Fan C.G.
Published: March 2011

High-speed cutting is a complexity and uncertainty process .The cutting parameters optimization is ambiguous. In this paper, based on the orthogonal experiment of high-speed milling aluminum alloy 7475, we use fuzzy comprehensive evaluation to optimize the parameters high-speed milling of aluminum alloy 7475 in the indication of surface roughness, cutting force, material removal rate. We have got cutting parameters optimal that is highly processing quality and productivity. Compared optimal results with orthogonal experimental results, we found that the optimal result is reliable. The study shows that fuzzy comprehensive evaluation method can optimize the parameters of high-speed milling of aluminum alloy 7475 accurately. This method has also a good application effect to other materials and great significance to guide actual production.
Research on Instantaneous Cutting Force of High Speed Ball-End Milling Cutter
Authors: Qi Chang Xing , Jiang Bin , Zheng Min Li , Yang Y.J. , Sun P.
Published: March 2011

For the instability of ball-end milling cutter in high speed milling, instantaneous cutting process of high speed milling hardened steel was studied. The model of instantaneous cutting layer parameters of high speed ball-end cutter was established, and the influence of cutting speed and inclination angles on instantaneous cutting layer parameters were obtained. Using the model, instantaneous cutting force was studied, and high speed milling experiment was processed. Results show that the increase of cutting speed makes the change rate of cutting layer parameters increasing, leads to the energy concentration in cutting process, and increases the impact on milling cutter. The increase of inclination angle makes the instantaneous cutting layer parameters show a trend of decrease and the decrease of cutting thickness more rapidly, which caused instantaneous unit cutting force to increase and the instantaneous main cutting force appears increasing trend, and the cutting process become unstable.
Research on Effects of Cutting Vibration on Surface Appearance
Authors: Jia Dong Kai , Wu S. , Wang Yan Xin , Yan F.G. , Li Y.F.
Published: March 2011

A model is established with considering the vibration effect of microstructure on milling surface formation, the impact of vibration on surface profile formation is also studied, which is simulated by the approach of vibration displacement in actual measurement. The on line monitoring of cutting vibration can be realized efficiently by the above method, and it is a coincident microstructure of milling surface between simulation and actual processing. In the result, it is cutting vibration that plays an main role in microstructure of milling surface formation with the known cutting parameters.
Cutting Force and Processing Parameters Optimization of Plunge Milling for Die Steel
Authors: Zhou Y.M. , Wang Cheng Yong , Yang Q.Y. , Song Y.X.
Published: March 2011

Plunge milling is used to remove excessive material rapidly in roughing machining. The cutter feed in the direction of machine spindle which has the highest structural rigidity. Through the single factor experiment of plunge milling a P20 die steel, this paper investigates the influence of side step, forward step, cutting speed, feed per tooth on cutting force. On this basis, the principles of optimization of interpolation milling parameters are proposed. This guidance of mold production practice has significant reference value.
Experimental Study and Modeling of Milling Force during High-Speed Milling of SiCp/Al Composites Using Regression Analysis
Authors: Huang Shu Tao , Yu X.L. , Zhou Li
Published: March 2011

SiCp/Al composites with high volume fraction and large particles are very difficult to machine. In this present study, high-speed milling experiments were carried out on the SiCp/Al composites by the three factors-levels orthogonal experiment method, and multiple linear regression analysis was employed to establish milling force model. The results show that the milling forces decrease with the increasing of the milling speed or increase with the increasing of the feed rate and depth of milling. The influence of milling depth on the milling forces in directions of x, y is the most significant, while the influence of the feed rate on the z-milling forces are the most significant. The calculation values from the milling force model are consistent with the experimental values. The results will provide a reliable theoretical guidance for milling of SiCp/Al composites, and it is feasible to predict the milling force during the milling of SiCp/Al by using this model.
Parameters Optimization of Turning Free Cutting Steel Based on the Coupling Method of Response Surfaces
Authors: Liu Zhi Qiang , Cai Xiao Jiang , Han Shu , Chen Ming , An Qing Long
Published: March 2011

Turning parameters are subject to processing efficiency, cutting force and surface quality, etc. A method, called the coupling method of response surfaces, is presented in this paper to select cutting parameters subjected to several constraints. An experiment of turning free cutting steel is made in order to set up the model. The results from the optimal selection provide a basis prototype for the cutting parameters. It can meet the needs of the turning process in industrial production.
Optimization of Cutting Parameters for Desirable Surface Roughness in End-Milling Hardened AISI H13 Steel under a Certain Metal Removal Rate
Authors: Ding Tong Chao , Zhang Song , Li Z.M. , Wang Yuan Wei
Published: March 2011

In this paper, the orthogonal experiments and the optimization experiments with the same metal removal rate are designed to investigate the main effects and primary interaction of cutting parameters on surface roughness and to search the optimal cutting parameter under a certain removal rate when end-milling hardened AISI H13 steel with the PVD coated carbide insert. The empirical model for surface roughness based on the orthogonal experiments and the optimization experiments with the same metal removal rate and the optimal cutting parameter were all verified. Under a certain metal removal rate, the combination of high cutting speed, small axial depth of cut and high feed, small radial depth of cut generates the best surface roughness in hard milling of AISI H13.
Experimental Research on Dry Cutting 34CrNiMo6
Authors: Yang Hao , Wang Xi Bin , Xie Li Jing , Pei J.J. , Wang T.
Published: March 2011

By dry cutting 34CrNiMo6, hard-machined material, with carbide cutting tool and ceramic cutting tool, experimental analysis was carried out in tool wear and cutting force. Cutting tool wear in the process is researched in order to obtain the cutting tool wear patterns and analyze the influencing factors. Meanwhile, it is found that the cutting force with the cutting parameters (cutting speed, cutting depth, feed) changes regularly, and then the experience formula of cutting force can be established.
Tool Wear Prediction when Maching Ti6Al4V Using Different Tool Materials
Authors: Fan Yi Hang , Zheng Min Li , Cheng Ming Ming , Zhang D.Q.
Published: March 2011

The tool life is different when using different tool materials machine Ti6Al4V under different cutting conditions. Based on the experiments of cutting Ti6Al4V using different tool materials, the tool wear prediction model is established with BP neural network theory. The wear prediction model is verified by further experiments. The results show that there is a valid prediction interval when using BP neural network predicts tool wear. When the cutting speed is in the vicinity of the training sample data, the relative error of the tool wear prediction and experimental results is less than 10%, which can meet the actual production. The tool wear prediction model is helpful for cutting tool material selection, cutting speed optimization and predomination the time of changing tool accurately when cutting titanium alloy.
Tool with Heavy-Duty Machining Tube Section of the Fatigue Analysis
Authors: Yu Zhong Guang , Liu Xian Li , Zhai Yuan Sheng , He Geng Huang , Li M.
Published: March 2011

Because the tube festivals surface is not round, uneven, so the cutting tool is under impact unceasingly in cutting process. Cutting tool is extremely easy to have fatigue failure, therefore it is very necessary to use finite element numerical analysis software ANSYS to carry on numerical simulation analysis for heavy lathe tool intensity static. The force of cutting tool and distributed rule of definite cutting tool internal stress strain could be precisely got by using FEM, thus the analysis results could improve cutting tool stress condition and the structural design provides the theory basis
Calculation of Indentation Hardness Based on Indentation Energy
Authors: Zhou L. , Guo Yong Ze , Liao Z.R. , Liang X.R. , Pan G.Q.
Published: March 2011

Comparing advantages and disadvantages of Oliver-Pharr method, microhardness method and indentation energy method, this article propses the improvement of indentation energy method. The improvement of indentation energy method mainly takes the calculation of energy and pile-up and sink-in phenomenon into account. Using Abaqus to simulate the indentation of aluminum with Vicker indenter, process and analyse data from simulation . By comparing different methods of hardness calculation , analyse the effect of improvement of hardness calculation.
Finite Element Method Modeling Approaches in Grinding
Authors: Zhang H.L. , Guo H.
Published: March 2011

In the present paper, a three-dimensional finite element model was used for simulating the grinding force at different cutting conditions. The effects of the wheel speed, feed and grinding depth on the grinding force per unit width were analyzed in detail. The results show that both the normal force and tangential force increase linearly with the increasing of feed and grinding depth, however, with the increasing of wheel speed, the grinding force decreases gradually. The predicted normal and tangential grinding forces were compared with those experimentally obtained and the results show reasonable agreement quantitatively.
Simulation of Residual Stress in Ultrasonic Vibration Assisted Micro-Milling
Authors: Hu Hai Jun , Sun Ya Zhou , Lu Z.S.
Published: March 2011

The machining-induced residual stresses are strongly dependent on the work-piece material and the chosen process parameters. A 2D finite element (FE) model of ultrasonic vibration assisted micro-milling (UVAMM) is established using ABAQUS. Johnson-Cook’s work-piece material and shear failure principle are used, while friction between tool and work-piece uses modified Coulomb’s law whose sliding friction area is combined with sticking friction. By means of FE analysis, the influence rules of spindle speed, vibration frequency and work-piece material on the surface residual stresses are obtained, which provides a basis for choosing optimal process parameters and improving the longevity and reliability of micro-component.
Aeroacoustic Performance Evaluation of Milling Cutters Based on the Flow Field on the Cutter Surface
Authors: Ji Chun Hui , Liu Zhan Qiang
Published: March 2011

Many workers all over the world suffer significant hearing loss as well as psychological and physical stress as a result of exposure to high levels of aeroacoustic noise. Dipole sources are the major noise sources in aeroacoustic noise generation in rotating face milling cutters. A noise model based on the Ffowcs Williams-Hawkings Equation is used to predict aeroacoustic noise; the noise predicted was 2.5dB less than the experimental observations. Flow field of cutter surface was numerically simulated by the resolution of the Navier-Stokes equations (CFD) and five zones on cutter surface were founded to be the important noise source. The broadband noise spreads over a broad range of frequencies and contributes significantly to overall noise, but the discrete noise at the rotational frequency is usually higher and more detrimental to the body.