bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature Robust PCA Based Stress Monitoring Approach
Authors: Quiroga Jabid , Quiroga John , Mujica Luis , Villamizar Rodolfo , Ruiz Magda
Published: October 2016

In this paper, a guided wave temperature robust PCA-based stress monitoring methodology is proposed. It is based on the analysis of the longitudinal guided wave propagating along the path under stress. Slight changes in the wave are detected by means of PCA via statistical T2 and Q indices. Experimental and numerical simulations of the guided wave propagating in material under different temperatures have shown significant variations in the amplitude and the velocity of the wave. This condition can jeopardize the discrimination of the different stress scenarios detected by the PCA indices. Thus, it is proposed a methodology based on an extended knowledge base, composed by a PCA statistical model for different discrete temperatures to produce a robust classification of stress states under variable environmental conditions. Experimental results have shown a good agreement between the predicted scenarios and the real ones
Measure of Nonlocal Response in Multiscale Gradient Modeling
Authors: Lesičar Tomislav , Tonković Zdenko , Sorić Jurica
Published: October 2016

Realistic description of heterogeneous material behavior demands more accurate modeling at multiple scales. Multiscale scheme employing second-order homogenization requires C1 continuity at the macrolevel, while classical continuum is usually kept at the microlevel (C1-C0 homogenization). However, due to C1-C0 transition, consistency of macroscale variables is violated. This research proposes a new second-order homogenization scheme employing C1 continuity at both scales. Discretization is performed by the C1 finite element and Aifantis gradient elasticity theory. A new gradient boundary conditions are derived. The relation between the Aifantis length scale and the RVE size has been found. The new procedure is tested on a benchmark example. After successful development of the C1-C1 multiscale scheme, the next step is an extension to consistent scaling of the microscale strain localization towards a macroscopic fracture.
Effect of Shot Peening on Fatigue Behavior of AISI 4340 in Different Loading Conditions
Authors: Torres Marcelo A.S. , Harada D.T. , Baptista Carlos Antonio Reis Pereira , Cindra Fonseca Maria P.
Published: October 2016

Shot peening is a method widely used to improve the fatigue strength of materials, through the creation of a compressive residual stress field (CRSF) in their surface layers. In the present research the gain in fatigue life of AISI 4340 steel, obtained by shot peening treatment, is evaluated under the three different hardnesses used in landing gear. Rotating bending fatigue tests and alternating tension tests were conducted and the CRSF was measured by x-ray tensometry prior and after interrupted fatigue tests. The evaluation of fatigue life after shot peening in relation to the relaxation of CRSF, of the crack initiation sites and surface roughness is done.
Effect of the Crack Surface Friction on the Field Strength of Bi-Material-Interfacial Crack
Authors: Li You Tang , Liu Lei
Published: October 2016

The stress field, displacement field and stress intensity factor are discussed based on elastic theory in this paper. The finite element model for interface crack of bi-material is set up, the friction phenomena of interface between two materials is simulated. The effect of crack size ratio and friction factor of crack surface on crack tip displacement, equivalent effective stress and stress intensity factor are analyzed. The results show that with the increase of the crack surface friction coefficient, the displacement and equivalent effective stress of the crack tip, and stress intensity factor will also increase under the condition of the same crack size. If the crack surface friction is ignored, the results will be not precise and are not in conformity with the practical engineering, even the significant impacts will disappear in the research for crack initiation, extension and fracture.
Modelling of Energy Dissipation during Fracture of Concrete Notched Beams: Proportion of the Effective Crack and the Fracture Process Zone Consumption
Authors: Klon Jiří , Veselý Václav
Published: October 2016

The paper presents an analysis aiming at capturing the phenomenon of quasi-brittle fracture based on the record of the fracture tests on notched specimens. A method of separation of the energy amounts released for the crack advance and that dissipated within the volume of the sizeable nonlinear zone at the crack tip – the fracture process zone– is introduced. The approach is tested on selected data of published experimental campaigns accompanied with own conducted numerical simulations.
A Novel Numerical Formulation for Crystal Plasticity
Authors: Benedetti Ivano , Gulizzi Vincenzo
Published: October 2016

Crystal plasticity plays a crucial role in the mechanics of polycrystalline materials and it is commonly modeled within the framework of the crystal plasticity finite element method (CPFEM). In this work, an alternative formulation for small strains crystal plasticity is presented. The method is based on a boundary integral formulation for polycrystalline problems and plasticity is addressed using an initial strains approach. Voronoi-type micro-morphologies are considered in the polycrystalline case. A general grain-boundary incremental/iterative algorithm, embedding the flow and hardening rules for crystal plasticity, is developed. The key feature of the method is the expression of the micro-mechanical problem in terms of inter-granular variables only, resulting in a reduction of the number of DoFs, which may be appealing in multi-scale applications. Some numerical results, showing the potential of the technique, are presented and discussed.
A MeshFree Micromechanical Analysis for Twill Composite
Authors: Li L. , Aliabadi M.H.
Published: October 2016

This paper presents homogenization of twill woven composites. It includes presenting formulated geometrical unit cell models, establishing meshfree micromechanical and CDM models for twill woven composites. The results cover meshfree nodal distributions, meshfree yarn geometries, predicted mechanical properties, effectiveness of yarn waviness, non-linear stress-strain relation of unit cell, stress distributions inside unit cell volume, and necessary comparisons with existing literatures.
Online Remaining Fatigue Life Prognosis for Composite Materials Based on Strain Data and Stochastic Modeling
Authors: Eleftheroglou N. , Zarouchas D.S. , Loutas T.H. , Alderliesten Rene C. , Benedictus R.
Published: October 2016

The present study utilizes a state-of-the-art stochastic modeling with structural health monitoring (SHM) data derived from strain measurements, in order to assess the remaining useful life (RUL) online in composite materials under fatigue loading. Non-Homogenous Hidden Semi Markov model (NHHSMM) is a suitable candidate with a rich mathematical structure capable of describing the composite’s multi-state damage evolution in time. The proposed model uses as input SHM data in the form of strain measurements obtained from the Digital Image Correlation (DIC) technique to a coupon-level constant amplitude fatigue test campaign. The obtained from the stochastic model RUL estimations are compared with the actual RUL and the effectiveness of the prognosis is discussed.
Displacement Correlation Technique for Interface Crack by FEM
Authors: Hinneh Perry , Wen Pi Hua
Published: October 2016

Interface crack is evaluated using modified quarter point crack tip displacement method. Quarter point elements around the crack tip were employed in the Finite Element (ABAQUS) analysis to determine the near crack tip grid point displacements. In this study, a technique is adopted in which the crack opening displacement of the near crack tip grid point is forced to satisfy a known constraint. The linear term in the distance around the crack tip is reduced to zero. The complex stress intensity factor for interface crack is determined using the quarter point and the displacement correlation technique. It is well observed that FEM produce a less reliable displacement approximation around interface crack tip. However, this report will show that the use of near crack tip open displacement as determined by the standard finite element method can be utilised to give satisfactory result for the interface stress intensity factors K1 and K2.
A Dual BEM Formulation for Thermo-Magneto-Piezo-Electric 2D Fracture Problems
Authors: Carrasco-Vela G. , García-Sánchez Felipe , Sáez Andrés , Rodríguez-Tembleque Luis
Published: October 2016

A hypersingular approach of the boundary element formulation -BEM- is presented for the analysis of the temperature in fracture problems of multifield materials. A fundamental solution based on the extended Stroh formalism is considered. Hypersingular integrals arising in the traction boundary and heat flux integral equations are computed through a regularization technique causing that only regular integrals are computed numerically. The generality of the method allows the study of 2D solids with no shape restrictions. Generalized intensity factors -IFs- are accurately computed from nodal values next to crack tip. Finally, the possibilities of the presented approach are discussed in order to apply it for the assessment of the influence of temperature in fracture problems for materialspresenting mechanical, magnetic and/or electrical coupling
Micromechanical Boundary Element Modelling of Transgranular and Intergranular Cohesive Cracking in Polycrystalline Materials
Authors: Geraci G. , Aliabadi M.H.
Published: October 2016

In this paper a cohesive formulation is proposed for modelling intergranular and transgranular damage and microcracking evolution in brittle polycrystalline materials. The model uses a multi region boundary element approach combined with a dual boundary element formulation. Polycrystalline microstructures are created through a Voronoi tessellation algorithm. Each crystal has an elastic orthotropic behaviour and specific material orientation. Transgranular surfaces are inserted as the simulation evolves and only in those grains that experience stress levels high enough for the nucleation of a new potential crack. Damage evolution along (inter-or trans-granular) interfaces is then modelled using cohesive traction separation laws and, upon failure, frictional contact analysis is introduced to model separation, stick or slip.
Moreover some physical consideration based on cohesive energies were made, in order to guarantee the cohesive model in consideration was appropriate for the purpose of this work.
Finally numerical simulations have been performed to demonstrate the validity of the proposed formulation in comparison with experimental observations and literature results.
Micromechanical Modeling of Crack Initiation and Propagation in the Ductile-Brittle Transition Region
Authors: Anh Giang Ngoc , Hütter Geralf , Kuna Meinhard
Published: October 2016

In the present study the crack initiation and propagation is investigated in the ductile-brittle transition region by means of a microscopic model. In particular, the particles in the process zone in front of the crack tip are resolved discretely in finite element simulations. The competing mechanisms of particle debonding and possible subsequent void growth as well as particle breakage and cleavage of the metallic matrix are incorporated explicitly in the micromechanical model by means of a cohesive zone. This approach accounts for the complex interactions of the mechanisms and allows to simulate all stages of crack initiation and propagation at all relevant temperatures.
Characterisation of Fracture and HAC Resistance of an Individual Microstructural Constituent with Micro-Cantilever Testing
Authors: Costin Walter , Lavigne Olivier , Kotousov Andrei G.
Published: October 2016

This paper focuses on the application of miniaturized fracture tests to evaluate the fracture and hydrogen assisted cracking (HAC) resistance of a selected microstructural constituent (acicular ferrite, AF) which only occurs in microscopic material volumes. Site-specific Focused Ion Beam (FIB) micro-machining was used to fabricate sharply notched micro-cantilevers into a region fully constituting of AF. The micro-cantilevers were subsequently tested under uncharged and hydrogen charged conditions with a nanoindenter. The load displacement curves were recorded and analysed with a simplified plastic hinge model for the uncharged specimen, as AF demonstrated an essentially ductile behaviour. The simplified model assisted with FE simulations provided values of the critical plastic crack tip opening displacement (CTOD). A value of the conditional fracture toughness was thereby determined as 12.1 MPa m1/2. With LEFM, a threshold stress intensity factor, Kth, to initiate hydrogen crack propagation in AF was found to range between 1.56 MPa m1/2 and 4.36 MPa m1/2. All these values were significantly below the corresponding values reported for various ferrous alloys in standard macro-tests. This finding indicates that the fracture and HAC resistance at the micro-scale could be very different than at the macro-scale as not all fracture toughening mechanisms may be activated at this scale level.
Comparative Study of Microstructure and High Temperature Low Cycle Fatigue Behaviour of Nickel Base Superalloys Inconel 713LC and MAR-M247
Authors: Šulák Ivo , Obrtlík Karel , Čelko Ladislav
Published: October 2016

The present work is focused on the study of microstructure and low cycle fatigue behavior of the first generation nickel-base superalloy IN 713LC (low carbon) and its promising second generation successor MAR-M247 HIP (hot isostatic pressing) at 900 °C. Microstructure of both alloys was studied by means of scanning electron microscopy (SEM). The microstructure of both materials is characterized by dendritic grains, carbides and casting defects. Size and morphology of precipitates and casting defects were evaluated. Fractographic observations have been made with the aim to reveal the fatigue crack initiation place and relation to the casting defects and material microstructure. Low cycle fatigue tests were conducted on cylindrical specimens in symmetrical push-pull cycle under strain control with constant total strain amplitude and strain rate at 900 °C in air. Hardening/softening curves, cyclic stress-strain curve and fatigue life data of both materials were obtained. Cyclic stress-strain curve of MAR M247 is shifted approximately to 120 MPa higher stress amplitudes in comparison with IN 713LC. Significantly higher fatigue life of MAR-M247 has been observed in Basquin representation. On the other hand IN 713LC shows prolonged lifetime compared with MAR-M247 in the Coffin-Manson representation. Results obtained from high temperature low cycle fatigue tests are discussed.
Effect of Media Degradation on Finishing Characteristics in Abrasive Flow Machining
Authors: Sato Takashi , Soh Edwin , Nakayama Yuuichiro , Shinagawa Miki , Fukuchi Yasuhiko
Published: October 2016

Abrasive flow machining (AFM) is one of the most promising technologies for internal finishing and de-burring for features with complex geometry. This study investigates the effect of media degradation on finishing characteristics achieved using the AFM process. A total of 50 experiments, using Inconel 718 cylindrical coupons machined by Wire-Electron Discharge Machining (WEDM), were conducted employing the same process conditions while using a single batch of AFM media. Experimental results indicate that media degradation has minor influence on surface roughness, but more significant influence on material removal and media flow rate. Material removal decreases exponentially with increasing cumulative media flow volume despite media flow rate increasing. There is a linear correlation between material removal and media flow rate. As a result, material removal can be estimated from media flow rate which can be monitored easily.
Effects of Electricity Parameters on Surface Quality of Reaction Bonded Silicon Carbide Ceramic with Electrical Discharge Diamond Grinding
Authors: Rao Xiao Shuang , Zhang Fei Hu , Li Chen
Published: October 2016

With some conductivity and low grinding affectivity, a hybrid machining process termed electrical discharge diamond grinding (EDDG) is applied to the precision machining of reaction bonded silicon carbide (RB-SiC) ceramic. As there is electrical spark in the hybrid machining process, the electrical parameters are varied to explore their effects on the surface quality of RB-SiC ceramic with EDDG. In this paper, the experiments of different polarity and gap voltage with EEDG were investigated, and the microstructure and surface roughness on the machined surface of RB-SiC ceramic were analyzed. The surface morphology and micro-cracks were examined with a scanning electron microscope, and the surface roughness was measured with a confocal scanning laser microscope. It is found that surface roughness initially increases and then decreases with increase of the gap voltages and is higher with negative polarity than that with positive polarity. The micromorphology Micro-cracks were observed on the surface machined and are outstanding in re-solidified zone with EDDG.
Experimental Research of Cluster Magnetorheological Finishing on Anodic Oxide Film of Aluminum
Authors: Chen Run , Lu Jia Bin , Yan Qiu Sheng , Xiao Xiao Lan , Li De Yuan
Published: October 2016

The polishing experiments of anodic oxide film of aluminum were performed to research the influence of polishing parameters on the surface roughness and material removal rate in the cluster magnetorheological finishing (MRF). Experimental results demonstrate that a mirror effect can be reached when the anodic oxide film of aluminum is polished by the Cluster MRF. The roughness of the workpiece surface after polishing for 15 min is decreased from Ra 0.575μm to Ra 4.13nm and the material removal rate is 0.653mg/min. With the extension of the polishing time, the surface roughness rapidly declines at first and then slowly decreases. When the machining time is more than 15min, the anodic oxide film of aluminum is easily worn out, resulting in a sharp increase in the surface roughness. The machining gap between the workpiece and the polishing plate influences the polishing effect of anodic oxide film of aluminum. With the increase of the machining gap, the material removal rate decreases and the surface roughness increases. A good surface quality can be got at the machining gap of 1.1mm. The type and size of abrasive particles will directly affect the polishing effect of anodic oxide film of aluminum, and when using CeO2 abrasive with the particle size of W3, a higher material removal rate and a smaller surface roughness can be obtained.
Estimation of Unsteady and Steady Polishing Force in Magnetic Abrasive Finishing Using a Permanent Magnet End-Mill Tool
Authors: Ma Lei , Furuki Tatsuya , Wu Wei , Hirogaki Toshiki , Aoyama Eiichi
Published: October 2016

Stable finishing is considered difficult to achieve using conventional magnetic abrasive because of its unstable polishing characteristics. In this paper, three different shapes of iron particles are used to produce a magnetic brush to improve stability. The unsteady and steady polishing force produced under the magnetic field of an end-mill type tool is discussed. We also develop prototype equipment combining a high speed camera with a force sensor to analyse micro-changes in the magnetic brush while machining. The relationship between the unsteady or steady polishing force and the polishing capability of the magnetic brush is explored in an attempt to construct a model for predicting polishing forces.
Ultrasonic-Vibration-Assisted Micromachining of Sapphire
Authors: Wakabayashi Hiroki , Koike Ryo , Kakinuma Yasuhiro , Aoyama Tojiro , Shimada Hiroyuki , Hamada Seiji
Published: October 2016

Sapphire is an attractive engineering material for the cover glass of smartphones and wristwatches because of its high hardness and resistance to corrosion, wear, and heat. However, the high rate of tool wear and brittle chippings around the holes are serious problems associated with drilling sapphire. To enhance the accuracy and efficiency of the drilling process on sapphire, this paper presents a novel tool-path strategy using helical milling along with various tool path patterns. Experimental results show that the proposed method successfully reduces brittle chippings around the holes.
Analysis of the Temperature Field of the Diamond Wheel Dressed Using Laser Assisted Ultrasonic-Vibration Combined Dressing Method
Authors: Yang Zhi Bo , Zhang Zhen , Yang Rui Yun , Liu Ai Ju
Published: October 2016

During the dressing process of diamond wheel using laser/ultrasonic-vibration combined dressing method, the removal mode of the local materials on the surface of wheel with the use of laser’s heating effect transits from brittle fracture to plastic flow, so that the wear of diamond dresser can be reduced and the dressing efficiency and surface dressing quality can be improved. Using ANSYS analysis software, the three-dimensional units were used and the nonlinearity of the material’s thermophysical properties was taken into account, and thereby, the finite element model of the temperature field of the diamond wheel heated by the laser during the dressing process was constructed. Then, the distributions of the temperature field on the surface and section of the wheel under different technological parameter were acquired. Moreover, the temperature distribution of the dressed wheel under actual working conditions was measured using infrared temperature measurement method. The results indicate that, under the same working conditions, the simulation results using finite element model fit well with the measured values, i.e., the finite element model has important guiding significance to the selection of technological parameters in dressing.
Fundamental Investigation of Ultrasonic Assisted Pulsed Electrochemical Grinding of Ti-6Al-4V
Authors: Li Si Si , Wu Yong Bo , Nomura Mitsuyoshi
Published: October 2016

Aiming at the development of a novel grinding technology for the highly efficient machining of difficult to machine materials such as Ti-6Al-4V, an ultrasonic assisted pulsed electrochemical grinding (UAECG) method was proposed. The current work is to reveal the fundamental grinding characteristics of the UAECG of Ti-6Al-4V by experimentally investigating the effect of vibration amplitude on grinding forces, actual material removal and work-surface roughness under different process parameters such as the input voltage and rotational speed. Summarizing the obtained results revealed that the grinding forces in UAECG are significantly smaller than those in conventional grinding (CG).
Characterisation of the Femtosecond Laser Micro-Grooving Process for Germanium Substrates
Authors: Li Lin , Wang Jun , Li Huai Zhong
Published: October 2016

An experimental study is reported to characterise the femtosecond (FS) laser grooving process for Germanium (Ge) substrates. The effects of process parameters, including laser fluence, pulse repetition rate and scan speed, on the groove characteristics, material removal rate (MRR) and heat affected zone (HAZ) size are discussed. It is shown that with properly selected process parameters, high quality micro-grooves can be obtained on Ge wafers. Recommendations are finally made on the selection of the most appropriate process parameters for FS micro-grooving of Ge substrates.
Machinability Improvement on High Speed Ultrasonic Turning - The Effect of Tool Oscillating Direction and Tool Chip Shape
Authors: Hara Keisuke , Sasaki Ryo , Isobe Hiromi
Published: October 2016

Ultrasonic cutting is a technique that can improve machinability such as fine surface, reduce tool worn out and etc. To improve processing speed of ultrasonic cutting is difficult due to the effects of tool oscillation are invalidated when cutting speed exceeds maximum tool oscillating velocity. In previous report, high speed principal direction ultrasonic turning experiments for stainless steel were carried out to improve processing speed and products quality. In ultrasonic turning, tool worn out and built up edge generation were reduced compare with ordinary turning. In this study, the effects of tool oscillating direction and tool chip shape for cutting properties of soft magnetic stainless steel were investigated. Cutting properties such as turned surface roughness, cutting force and ejected chip were compared.
Effects of Grinding Fluid Excited by Ultrasonic Vibration
Authors: Trung Hieu Nguyen , Ishimatsu Jun , Isobe Hiromi
Published: October 2016

Ultrasonic excited fluid has been researched for machining of hard-to-grind materials. Ultrasonic vibration is applied to grinding fluid by an ultrasonic oscillating comb-shape effecter with integrated nozzle. Grinding fluid discharges from a nozzle placed between the comb’s feet and passes through the vacant space between comb teeth. By this setup, flowing grinding fluid can be continuously excited by ultrasonic vibration. Based on the principle of an ultrasonic washing machine, impulsive force caused by cavitation bubble will reduce the adhesion of chips on the cutting face of grain and chip pockets. Some effects of ultrasonic excited grinding fluid have been recorded such as reducing grinding heat in the case of grinding for Titanium alloy and decreasing in grinding force, improving surface roughness in the case of grinding for Aluminum and stainless alloy. However, the reason of better grinding performance is still unknown. Therefore, experiments conducted with different type of grinding fluids with and without ultrasonic vibration are needed. Pure Titanium, which considered a hard-to-cut material, is chosen as work material. Grinding forces and grinding heat during grinding will be measured and evaluated to clarify the mechanism of ultrasonic excited grinding fluid.
Experimental Investigation and Optimization in Rotary Ultrasonic Drilling of C/C Composites
Authors: Yuan Song Mei , Wu Qi
Published: October 2016

C/C composites are widely used in aviation and aerospace due to their low density, superior specific strength, special elastic modulus at elevated temperatures, small thermal expansion coefficient and high fracture toughness. However, there are numerous problems such as delamination, chipping, poor machining quality and tool wear in drilling of C/C composites due to inhomogeneous, anisotropic, wear resistance and varying thermal properties of the composites. In this paper, related experiments on rotary ultrasonic drilling of C/C composites using diamond core drill were conducted to compare the drilling force and machining quality of ultrasonic drilling with conventional drilling, analyze the rotary ultrasonic drilling mechanism and research the influence of spindle speed, feed rate and ultrasonic amplitude on the drilling force. Experimental results showed that rotary ultrasonic drilling can significantly improve the removal of the chips thus preventing the core drill blockage, effectively reduce the drilling force and improve processing quality. In addition, the drilling force decreased with increasing of spindle speed and ultrasonic amplitude, while it increased with increasing of feed rate. Finally, the cutting parameters were optimized by consideration of the drilling force and efficiency.
Deformation Twinning of Molecular Dynamics Simulation in a Ternary Titanium Alloy under Nanoindentation
Authors: Huang Si Ling , Zhang Zhen Yu , Cui Jun Feng , Yang Song , Guo Xiao Guang
Published: October 2016

Nanotwinned (nt) metals exhibit excellent mechanical, electrical and thermal properties, and therefore attract much attentions. To fabricate large area nt surface, the fundamental mechanisms of deformation twinning induced by molecular dynamics (MD) are necessary to be explored. Nevertheless, MD of nt metals currently focus mainly on nt copper (Cu) and other single element metals with face-centered cubic (fcc) structure. In addition, MD simulations are usually performed on a built nt model, rather than from a single crystal, due to the difficulty of forming nanotwins. In this study, a single crystal is constructed in a ternary titanium (Ti) alloy with hexagonal closed-packed (hcp) lattice cell. Deformation twinning of MD simulation is performed in a ternary Ti alloy under nanoindentation from the built single crystal. Zonal structure is found during loading under nanoindentation, and nanograins transforms into nanotwins. Deformation twinning is significant to understanding the formation of nanotwins, as well as fabricating large area nt surface on a Ti alloy.
Mechanical Property and Characterization on Diamond Films Deposited on WC-Co Substrates
Authors: Zhou Hong Xiu , Li Ming Lei , Yuan Bo Ya
Published: October 2016

Cutting tools of WC-Co are widely used in cutting field. Nevertheless, its wear resistance and lifetime are not qualified for the high performance cutting. Therefore, diamond films are deposited on WC-Co substrates to overcome its disadvantages. In this paper we investigate the effects of the pretreatment on substrates and as-deposited WC-Co samples by using a hot filament chemical vapor deposition (HFCVD) reactor. Prior to deposition, the WC-Co substrates were submitted to surface roughening by Murakami reagent and to surface binder removal by Caro’ acid with varied durations. Surface roughness Ra determined by AFM varied from 110 to 279 nm. The diamond films are characterized by scanning electron microscopy (SEM) and Raman spectroscopy, whose results present a sharp peak at 1336 cm-1 indicating sp3 diamond. The adhesion between the diamond films and substrates was evaluated by pull-off tests with the highest adhesion strength is 26.92 MPa. Cracked interface is characterized between diamond films and substrates, using SEM and energy dispersive spectroscopy (EDS) to analyze the adhesion performance.
Oxide Film Generation during Titanium Alloy Turning in Oxygen-Enriched Atmosphere
Authors: Wan Yi , Liu Zhan Qiang , Zhang Rui , Wang Zhen
Published: October 2016

The physical and chemical properties of bio-titanium alloy implant surface play an important role on corrosion resistance and biological activity. New turning processes under oxygen-rich atmosphere were presented to obtain required titanium dioxide layer, which can protect implants from corrosion. The thickness of the oxidation film were observed using Auger Electronic Spectrum (AES). Then the corrosion resistance was tested in simulated body fluid by electrochemical corrosion. The results showed that the thickness of oxidation film by turning in oxygen-rich 80% was 69 nm, which was 4.6 times of that under natural conditions (15 nm). The thickness of processing surface oxidation film was increased by turning process under oxygen-rich atmosphere, indicating that this process could slow down the speed of titanium alloy corrosion and significantly improve the corrosion resistance.
Processing Single Crystal SiC with Semi-Consolidated Polishing Film
Authors: Lu Jing , Hu Guang Qiu , Guo Hua , Xu Xi Peng
Published: October 2016

Single crystal SiC has been considered as a leading wide band gap semiconductor for its excellent properties even in severe environments. While the outstanding chemical and mechanical inertness also makes it a difficult to process material. In this work, a flexible machining method was proposed to polish 6H-SiC wafers with semi-consolidated diamond tools prepared by sol-gel technology. To confirm the machining mechanism of this newly developed method, free abrasive polishing slurry and fixed abrasive lapping film were also used for comparative experiments. The results indicated that high quality wafer surface with roughness of Ra 0.962 nm was achieved by using semi-consolidated polishing film with diamond grit size of 1 μm. And compared to the other two machining methods, the abrasive in this flexible tool would take a retraction when polishing, leading to a smoother and scratch-free surface of the work piece.
Effects of Cutting Atmosphere on High-Speed End Milling Process for Titanium Alloy Ti6Al4V
Authors: Kondo Eiji , Goto Daisuke , Nishimura Yuki , Nakao Mitsuhiro
Published: October 2016

As titanium alloys have a high strength-to-weight ratio and superior corrosion resistance, they are widely used in the aerospace, biomedical, and automotive industries. However, these alloys exhibit very poor machinability, which results in problems such as short tool life. This study investigates the effect of the cutting atmosphere on tool wear during high-speed end milling of the titanium alloy Ti6Al4V. Dry cutting, cold air jet cutting, cutting fluid mist jet cutting, and cutting fluid flush cutting were considered in order to determine the optimum cutting atmosphere and conditions. For down-cutting speeds of 200−300 m/min, the cutting atmosphere and cutting speed were adopted as experimental parameters. Down-cutting was performed in order to measure the width of the tool flank wear land as the cutting length was increased. The results indicated that the optimum cutting method was cold air jet cutting. For a cutting length of 500 mm, this method produced a narrower flank wear land than dry cutting. In addition, for longer cutting lengths of up to 4000 mm, the wear rate for cold air jet cutting was less than or equal to that for dry cutting, and no chipping or excessive wear was observed.
Development of the Axial Splitting Process for Small Diameter Brass Tubes
Authors: Nakanishi Eitoku , Sugiura Koji , Tezuka Masashi , Koda Yuya , Yoshino Ichiro , Hachikawa Shuichi
Published: October 2016

We developed the equipment for splitting the long and small diameter tube, with using a splitting tool which was previously developed [1]. The splitting target is brass tube. Its length is about 500mm and the diameter is about 19mm. Because of the high aspect ratio, it is considered to cause a buckling easily. The developed equipment has a special gripping device for the long brass tube. Also the end of the long brass tube is gripped by the unique jig. As a result, it is shown that the brass tube (500mm length, 19mm of diameter and the thickness of the wall is 1.2mm) can be split in axial direction along its full length by using the developed tool and equipment.
Experimental Research on Small-Diameter Deep-Hole Drilling of Austenite Stainless Steel
Authors: Kodama Hiroyuki , Okuda Koichi , Yamaguchi Toshiya
Published: October 2016

Experiments were conducted with the main objective of improving the precision of drilling small-diameter, deep holes in austenite stainless steel (JIS SUS304). In the experiments, the step feed amount, rotation speed, and feed rate were varied and the thrust force and cutting temperature were measured to investigate the effect of cutting conditions on hole properties in drilling small-diameter deep holes. The results show that a combination of step feed amount and feed rate can reduce thrust force and drilling time, and that making the step feed small can suppress the cutting temperature.
Effect of Cutting Speed on the Face Milling of CFRP Using a PCD Tool
Authors: Kitajima Takayuki , Horiuchi Takumi , Yui Akinori , Ito Yosuke
Published: October 2016

Carbon-fiber-reinforced plastic (CFRP) is used in various industries such as aerospace and automobile industries because of its high mechanical characteristics. However, this material is difficult to cut. Tool wear and delamination frequently occur during the drilling or cutting of CFRP. In previous studies, we developed a CFRP cutting tool using polycrystalline diamond (PCD). The PCD tool exhibited excellent cutting performance at cutting speeds as low as <120 m/min. In this study, the authors investigated the effect of cutting speed on the face milling of CFRP by using the developed PCD tool.
Tapping Performance by Use of Strong Alkali Ion Water
Authors: Iwai Manabu , Yamada Masahide , Suzuki Kiyoshi
Published: October 2016

The authors have been conducting a research to apply strong alkali ion water (pH12 or so) to a working fluid for material removal processing. This is to cope with various problems relating to the existing water-soluble working fluid such as coolant putridity and the associated deterioration of factory environments and increased disposal costs of working fluids as well as to improve machining efficiency and tool life. In this study, the strong alkali ion water was applied to the tapping (M10) of stainless steel (SUS440C). As a result, use of the strong alkali ion water was found to contribute to the tool life improvement.
Spin Turning of Hardened Steel Using a Rod Tool Made of Cemented Carbide and On-Machine Forming of Rod Tool
Authors: Koga Fumio , Ninomiya Shinichi , Suzuki Kiyoshi
Published: October 2016

Use of a tool driven by a spin turning method on a 5 axis turning center has an advantage in suppressing a tool wear in the external turning of hard-to-machine materials. However, it is important not easy to control a radial runout of the tool periphery in the spin turning. In this research, a simple rod shaped tungsten carbide was applied as a rotating tool to the turning of a hardened steel workpiece (HRC63). In addition, on-machine grinding method was proposed as a measure to minimize a radial runout of the rotating tool. With this technique, a well suited rake angle, relief angle or chip breaker profile could be easily given to the tool. In spin turning of the hardened steel with a WC rod tool, roughness value of the worked surface was reduced and tool wear was suppressed in comparison with the turning without tool rotation. In addition, it was shown that correction of the tool runout and forming of the tool rake face could be done on the machine.
Estimation of Machining Error Caused by Deflection of Tool Using Cutting Force in Ball End Milling of Inclined Surface
Authors: Shimana Kenji , Kondo Eiji , Yoshimitsu Shinichi , Kobaru Yuya , Yamashita Shunichi
Published: October 2016

For a cutting process using a low-rigidity end mill, it is very important to be able to estimate the machining error caused by the deflection of the tool. The purpose of this study is to establish a method for the real-time estimation of the machining error caused by the deflection of the tool at the cutting point of a ball-end mill. The method was verified by comparing the estimated deflection and the machining error when milling an inclined surface. It was concluded that the machining errors in ball-end milling of inclined surfaces can be estimated from the normal force at the moment when the radial direction of the peripheral cutting edge is normal to the feed direction of the tool.
Centrifugal Internal Grinding by Assembled Wheel with Radially Mobile Segments
Authors: Blurtsyan David
Published: October 2016

Productivity of internal grinding processes is limited by wheel-workpiece contact area and high temperature generated during grinding. Existing internal grinding methods do not guarantee presence of coolant liquid in the heat generation zone. Usually coolant liquid from external nozzles could not penetrate turbulent air flow around grinding wheel. Assembled wheel with radially mobile segments allows increasing contact area but needs to be supported by more efficient heat evacuation system. New grinding wheel and method of internal grinding are developed and evaluated. New tool generates high speed hydrodynamic circular flow and dynamic wedges of coolant liquid in the cutting zones.
Evaluation of Electrochemical Properties, Study of Chemical and Mechanical Stability Supported with Ionic Transport and Surface Charge Density Mechanism of PVC Based Cobalt Tungstate Cation Exchange Membrane
Authors: Ali Khan Mohammad Mujahid , Khan Anish
Published: October 2016

The chemical and mechanical stability of membrane play a important role for understanding the mechanism and applications of cobalt tungstate cation exchange membrane. The PVC based cobalt tungstate (CT) membrane has been prepared by different methods like sol-gel, die-casting and others material processing techniques. It has been prepared through the mixing of PVC with cobalt tungstate into a definite ratio (1:3) that shows good mechanical stability. Moreover, the paper is concerned with physico-chemical and electro-chemical characterization of membrane, namely fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical studies. The results of characterization and electrochemical studies offered the potential industrial applications of membrane in different areas.
Materials and Methods of Contraception
Authors: Khanam Deeba
Published: October 2016

Contraception means interference in the process of ovulation, fertilization or implantation. This is an old practice and dates back to ancient times and continues to modify and remodify itself according to the social customs and demands of the society. This chapter discusses various forms and methods of contraception, their efficacy, advantages and disadvantages of their use, their importance in present scenario and their impact on the society. Unwanted pregnancies and their termination attempt can be hazardous if not dealt in proper way, so avoidance of pregnancy is considered the best way out for physical and mental health of the patient and thereby focuses the importance of contraception practice and health education.
A Novel Biodegradable Cinnamic Acid Grafted Carboxymethyl Cellulose Based Flocculant for Water Treatment
Authors: Pal Pinki , Pandey J.P. , Rahul Rahul , Sen Gautam
Published: October 2016

Cinnamic acid grafted carboxymethyl cellulose (CMC-g-P (CA)) has been synthesized by microwave assisted technique, which is an alliance of microwave radiation with chemical free radical initiator (CAN) to commence grafting. The novel graft copolymer has been characterized by physicochemical techniques – FTIR spectroscopy, intrinsic viscosity measurement, elemental analysis (C, H and N), SEM micrograph and TGA study. The flocculation efficacy and range of turbidity during the sedimentation stage for synthesized material has been investigated in kaolin suspension by ‘Jar test’ procedure. The optimal dosage of CMC-g-P (CA) as flocculant in kaolin suspension is at 10 ppm and it showed lowest range of turbidity (176-61 NTU) during sedimentation stage.
Multiple organ failure as onset of Mediterranean spotted fever: a review based on a case
Authors: Mansueto Pasquale , Seidita Aurelio , Bongiovì Accursia , Catalano Tiziana , Pirrone Giuseppe , Cusimano Claudia , D'Alcamo Alberto , Carroccio Antonio
Published: October 2016

Mediterranean spotted fever (MSF) is an infectious disease endemic in the southern regions of Italy, with an incidence of about 400 cases/year. The bacteria responsible of the disease is Rickettsia conorii, transmitted to humans by Rhipicephalus sanguineus, the common dog tick. The infection usually manifests with a characteristic symptomatologic triad: fever, exanthema and the so called tache noire, which is the typical eschar at the site of the tick bite. Immunoglobulin M (IgM) and IgG enzymelinked immunosorbent assay and the gold standard micro-immunofluorescent assay, allow serological diagnosis. We report the case of a man suffering from MSF, whose atypical presentation and false-negative diagnostic tests delayed consistently diagnosis and therapy. Afterwards we review the literature about this topic.
Adult bacterial myositis: report of a single-center series of 26 cases
Authors: Gallucci Fernando , Ronga Ilaria , Di Pietto Francesco , Amato Gerardino , Buono Rosario , Uomo Generoso
Published: October 2016

Bacterial infections involving muscle are quite uncommon and generally require specific predisposing factors. Bacterial myositis is more rarely described in the typical kind of patients observed in Internal Medicine (presence of multiple co-morbidities, partial/limited immune-deficiency, advanced age). Twenty-six patients suffering from bacterial myositis (8 women and 18 men; mean age 58.5 years, range 27-82) observed in a single Internal Medicine Unit were reported. Muscles involved were ileopsoas, thigh, paravertebral, gluteus, calf, forearm and rectus abdomen. Simultaneous presence of arthritis was registered in 17 patients and all patients presented relevant comorbidity. Main cultured bacteria were Staphylococcus aureus, Escherichia coli, other Gram-negative bacteria, Streptococcus spp. Multi-drug-resistance was observed in 14 out 26 (53.8%). Computed tomography, ultrasound and magnetic resonance imaging were utilized for diagnostic purposes. Antibiotic treatment was administered to all patients. Surgical debridement and drainage were performed in 12 patients; 7 patients were treated with percutaneous aspiration and drainage. At discharge, relevant functional impairment was present in 17 patients (65.3%). Four patients died (in-hospital mortality 7.6%, global mortality at three months 15.3%). Management of bacterial myositis is difficult and its prognosis is poor. In the near future, this demanding infection will be more frequently observed in Internal Medicine setting as comorbidity, which is very often the main characteristic of these patients.
Comparison between latex and microscopic agglutination test for detection of human leptospiral antibodies
Authors: Sakhaee Ehsanollah , Golchin Mehdi , Davoodian Zahra
Published: October 2016

Leptospirosis, notably Weil’s syndrome, is an often severe, acute febrile illness caused by microorganisms of the genus Leptospira. The microscopic agglutination test (MAT) is the basic method for the sero-diagnosis of leptospirosis, as the test has a high sensitivity and can be used for classification, but has some disadvantages. Therefore, we have explored latex agglutination test (LAT) for use as a practical and rapid for sero-diagnosis of human leptospirosis and compared the applicability of commercial tests MAT and LAT in the detection of specific antibodies against Leptospira interrogans in human.
Procalcitonin: handle with care
Authors: Chesi Giuseppe , Vazzana Natale , Dall’Orto Filippo
Published: October 2016

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