bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiopathologic Mechanisms Involved in Mare Endometrosis
Authors: Rebordão MR , Galvão A , Szóstek A , Amaral A , Mateus L , Skarzynski DJ , Ferreira‐Dias G
Published: October 2014

Contents

Endometrosis is a degenerative chronic process, characterized by paramount fibrosis development in mare endometrium. This condition is one of the major causes of subfertility/infertility in mares. As in other organs, fibrosis might be a pathologic sequel of many chronic inflammatory diseases. However, aetiology and physiopathologic mechanisms involved in endometrial fibrosis are still controversial. This review presents new hypotheses based on our newest data. As the first line of innate immune defence, systemic neutrophils arrive in the uterus at mating or in the presence of pathogens. A novel paradigm is that neutrophils cast out theirDNAin response to infectious stimuli and form neutrophil extracellular traps (NETs). We have shown that bacterial strains ofStreptococcus zooepidemicus, Escherichia coliorStaphylococcus capitis, known to cause endometritis in mares were able to induceNETs releasein vitroby equinePMNto different extents. An intriguing dilemma is the dual action ofNETs. WhileNETs play a desirable role fighting micro‐organisms in mare uterus, they may also contribute to endometrial fibrosis. A long‐termin vitroexposure of mare endometrium explants toNETs components (myeloperoxidase, elastase and cathepsin G) up‐regulated fibrosis markersTGFβand Tissue inhibitor of metalloproteinase (TIMP‐1). Also, pro‐fibrotic cytokines regulated collagen deposition and fibrosis. Changes in expression of connective tissue growth factor (CTGF), interleukins (IL)1‐α,IL‐1β,IL‐6 and receptors in endometrium with different degrees of fibrosis and/or inflammation were observed. A putative role ofCTGF,ILandNETs components in endometrosis development should be considered. Additionally, we speculate that in sustained endometritis in mares, prostaglandins may not only cause early luteolysis or early pregnancy loss, but may also be related to endometrial fibrosis pathogenesis by stimulating collagen deposition.
Modelling central metabolic fluxes by constraint‐based optimization reveals metabolic reprogramming of developing Solanum lycopersicum (tomato) fruit
Authors: Colombié Sophie , Nazaret Christine , Bénard Camille , Biais Benoît , Mengin Virginie , Solé Marion , Fouillen Laëtitia , Dieuaide‐Noubhani Martine , Mazat Jean‐Pierre , Beauvoit Bertrand , Gibon Yves
Published: October 2014

Modelling of metabolic networks is a powerful tool to analyse the behaviour of developing plant organs, including fruits. Guided by our current understanding of heterotrophic metabolism of plant cells, a medium‐scale stoichiometric model, including the balance of co–factors and energy, was constructed in order to describe metabolic shifts that occur through the nine sequential stages of Solanum lycopersicum (tomato) fruit development. The measured concentrations of the main biomass components and the accumulated metabolites in the pericarp, determined at each stage, were fitted in order to calculate, by derivation, the corresponding external fluxes. They were used as constraints to solve the model by minimizing the internal fluxes. The distribution of the calculated fluxes of central metabolism were then analysed and compared with known metabolic behaviours. For instance, the partition of the main metabolic pathways (glycolysis, pentose phosphate pathway, etc.) was relevant throughout fruit development. We also predicted a valid import of carbon and nitrogen by the fruit, as well as a consistent CO2 release. Interestingly, the energetic balance indicates that excess ATP is dissipated just before the onset of ripening, supporting the concept of the climacteric crisis. Finally, the apparent contradiction between calculated fluxes with low values compared with measured enzyme capacities suggest a complex reprogramming of the metabolic machinery during fruit development. With a powerful set of experimental data and an accurate definition of the metabolic system, this work provides important insight into the metabolic and physiological requirements of the developing tomato fruits.
Cyperus rotundus control using a mechanical digger and solar radiation
Authors: Hershenhorn J , Zion B , Smirnov E , Weissblum A , Shamir N , Dor E , Achdari G , Ziadna H , Shilo A
Published: October 2014

Cyperus rotundus (purple nutsedge) is considered one of the most noxious weeds affecting agricultural areas worldwide. With its fast growth rate, it competes with annual crops for water, minerals, light and space. It excretes allelopathic materials that impede crop development. Controlling this weed is difficult and is done mostly by manual weeding, cultivation and herbicides, with limited effectiveness. A method was developed for the control of C. rotundus. A machine penetrates the soil and rearranges it, so that the tubers are lifted to the upper soil layer, where they are left exposed to the hot summer climate, dehydrate and die. The method was tested in seven field experiments on various soil types. Two months after the experimental plots were irrigated, 70–100% weed control was observed. The machine's speed (at 1.2 or 1.8 km h−1) and the number of treatments (one, or two treatments a month apart) did not influence the level of weed control. The method has a very high potential to replace manual weeding and application of herbicides. Further work will test whether the treatment has a long‐term effect or should be repeated every season.
Quantitative reproductive potential of Heterodera schachtii on weeds typical for late summer fallow in sugar beet rotations
Authors: Meinecke A , Westphal A
Published: October 2014

In Europe, sugar beet is often produced in a 3‐year rotation with cereals, leaving stubble fields fallow from cereal harvest until primary tillage in autumn in the year prior to sugar beet production. The weed flora on such fields could include host plants of Heterodera schachtii that is one of the most important pests of sugar beet. Crop sequences with non‐hosts and cover cropping with resistant cruciferous hosts during this period have been crucial for its management. Availability of resistant and tolerant sugar beet cultivars could entice growers to forego cover cropping, exacerbating weed problems during the fallow period. The objective of this study was to determine the reproductive potential of H. schachtii on weeds that develop during this period. Under glasshouse conditions, reproduction on 39 plant species was compared with that on oilseed radish and sugar beet of differing nematode host status. In 2 years in field microplots, 18 previously tested species were grown in H. schachtii‐infested soil during the typical fallow period at 60 plants m−2, and nine of these species were also grown at 180 plants m−2. There were variable results between years after 8 weeks of growth, but most weeds allowed lower reproduction (<10%) than the susceptible sugar beet; only Stellaria media at 180 plants m−2 and Thlaspi arvense at both plant densities increased nematodes. Such weed densities may seldom occur under commercial conditions; thus, weed management for nematological considerations during the stubble period may have limited importance.
Recent Advances in Machining of Austempered Ductile Iron to Avoid Machining Induced Microstructural Phase Transformation Reaction
Authors: Polishetty Ashwin , Littlefair Guy
Published: October 2014

Austempered Ductile Iron (ADI) is a type of nodular, ductile cast iron subjected to heat treatments — austenitising and austempering. Whilst machining is conducted prior to heat treatment and offers no significant difficulty, machining post heat treatment is demanding and often avoided. Phase transformation of retained austenite to martensite leading to poor machinability characteristics is a common problem experienced during machining. Study of phase transformations is an investigative study on the factors — plastic strain (εp) and thermal energy (Q) which effect phase transformations during machining. The experimental design consists of face milling grade 1200 at variable Depth of Cut (DoC) range from 1 to 4 mm, coolant on/off, at constant speed, 1992 rpm and feed rate, 0.1 mm/tooth. Plastic strain (εp) and martensite content (M) at fracture point for each grade was evaluated by tensile testing. The effect of thermal energy (Q) on phase transformations was also verified through temperature measurements at DoC 3 and 1 mm using thermocouples embedded into the workpiece. Finally, the amount of plastic strain (εp) and thermal energy (Q) responsible for a given martensite increase (M) during milling was related and calculated using a mathematical function, M = f (εp, Q). The future work of the thesis involves an in-depth study on the new link discovered through this research: mathematical model relating the role of plastic strain and thermal energy in martensite formation.
Technology and Mechanical Properties of Samples Obtained by Injection From Arboform L, V3 Nature Reinforced With Aramid Fibers
Authors: Nedelcu Dumitru , Carausu Constantin , Ciofu Ciprian
Published: October 2014

The use of recyclable materials has become an important trend in all activity areas, reason why material based on liquid wood called Arbofill, Arboblend and Arboform will replace plastic in different applications in the near future. The new materials are the main substances that have an important effect on company development and require some simple or complex manufacturing technologies. In case of Arboform L, V3 Nature the injected parts can be obtained using the same injection machines used for the injection of plastic materials. The technological injection parameters, such as: injection pressure, injection time, cooling time, mold temperature, etc., are different. The experimental research focused on tensile strength, friction coefficients, SEM analysis, XRD analysis and EDAX analysis. Considering all of these experimental results the Arboform L, V3 Nature reinforced with aramid fibers could replace the following plastic materials PA12, PVDF, ECTFE, PA66, PA12, PC, PP, PP GF 30, etc. Also taking into account all the results obtained, this material can replace plastic materials in many applications, such as: ornaments, including for cars, connectors, switches etc., electrical industry, different mobile accessories, computers, televisions, mobile phone cases, etc. The material obtained from Arboform reinforced with aramid fibers (5% percent) improved the injection process despite of easy decreasing of mechanical properties.
Integrated Real-Time Event Based Cost Modeling of Battery Manufacturing System
Authors: Li Yang , Chang Qing
Published: October 2014

Information of battery manufacturing system is becoming increasingly transparent, detailed and real-time. Despite the big potential in improving productivity, the advantages of information are not fully realized due to a lack of system level modeling. Motivated by this need, we develop an integrated system modeling approach to quantify the systematic impact of stations and supporting activities with a unified index called event based cost (EBC). The analysis provides a severity ranking of stations and supporting activities. A case study is conducted to demonstrate the application of the model in a battery production system and its ability to facilitate decision making.
An Enhanced Microstructure-Level Finite Element Machining Model for Carbon Nanotube (CNT)-Polymer Composites
Authors: Jiang Lingyun , Nath Chandra , Samuel Johnson , Kapoor Shiv G.
Published: October 2014

During the machining of carbon nanotube (CNT)–polymer composites, the interface plays a critical role in the load transfer between polymer and CNT. Therefore, the interface for these composites has to be explicitly considered in the microstructure–level finite element (FE) machining model, so as to better understand their machinability and the interfacial failure mechanisms. In this study, a microstructure–level FE machining model for CNT–polymer composites has been developed by considering the interface as the third phase, in addition to the polymer and the CNT phases. For the interface, two interfacial properties, viz., interfacial strength and fracture energy have been included. To account for variable temperature and strain rate over the deformation zone during machining, temperature– and strain rate–dependent mechanical properties for the interface and the polymer material have also been included in the model. It is found that the FE machining model predicts cutting force within 6% of the experimental values at different machining conditions and CNT loadings. The cutting force data reveals that the model can accurately capture the CNT pull-out/protrusion, and the subsequent surface damage. Simulated surface damage characteristics are supported by the surface topographies and roughness values obtained from the machining experiments. The study suggests that the model can be utilized to design the new generation of CNT-polymer composites with specific interfacial properties that minimize the surface/subsurface damage and improve the surface finish.
Comparison of Microscale Rapid Prototyping Techniques for Microfluidic Applications
Authors: Hoople Gordon D. , Rolfe David A. , McKinstry Katherine C. , Noble Joanna R. , Dornfeld David A. , Pisano Albert P.
Published: October 2014

Recent developments in microfluidics have opened up new interest in rapid prototyping with features on the microscale. Microfluidic devices are traditionally fabricated using photolithography, however this process can be time consuming and challenging. Laser ablation has emerged as the preferred solution for rapid prototyping of these devices. This paper explores the state of rapid prototyping for microfluidic devices by comparing laser ablation to micromilling and 3D printing. A microfluidic sample part was fabricated using these three methods. Accuracy of the features and surface roughness were measured using a surface profilometer, scanning electron microscope, and optical microscope. Micromilling was found to produce the most accurate features and best surface finish down to ∼100 μm, however it did not achieve the small feature sizes produced by laser ablation. 3D printed parts, though easily manufactured, were inadequate for most microfluidics applications. While laser ablation created somewhat rough and erratic channels, the process was within typical dimensions for microfluidic channels and should remain the default for microfluidic rapid prototyping.
Technological Heredity and Accuracy of the Cross-Section Shapes of the Hydro-Cylinder Cylindrical Surfaces
Authors: Kryvyi Petro D. , Dzyura Volodymyr O. , Tymoshenko Nadiya M. , Krupa Volodymyr V.
Published: October 2014

It was proposed to estimate the accuracy of the hydro-cylinder cross-section shapes basing on the analysis of the circle diagram of their inner cylindrical surfaces, formed by the manufacturing operations, such as rough and semi-finishing boring and finishing paying-out, taking advantage of the method of deflection approximation from the circle by the Fourier’s trigonometric series in the gap [0, 2π].

Characteristics of the deflection dispersion of the radius-vector as the random value (average value, dispersion, amplitude spectrum) have been obtained for every circle diagram separately. It is proposed to present these characteristics as random values.

Dependences for finding mathematic expectation and dispersion for the lot of parts, machined at every of the available manufacturing operation, have been obtained for certain number of samples and circle diagrams, taking advantage of the small sampling theory, the method of rectangular engagement in particular.

The effectiveness of manufacturing operations has been estimated according to the Student and Fisher t-test. Availability of the advantageous or disadvantageous manufacturing heredity of the hydrocylinder cross-section shape has been found.

As the result of carried out experimental investigations and processing of the obtained statistic data on the inner cylindrical surface of the truck hoist crane hydrocylinder KTA-25, produced by the company “Drogobych truck crane plant” (Ukraine), the need to improve the manufacturing operation of the semi-finishing boring has been analysed.
Numerical Simulation of the Austenitizing Process in Hypoeutectoid Fe-C Steels
Authors: Liu Dehao , Wang Gang , Nie Zhenguo , Rong Yiming (Kevin)
Published: October 2014

For predicting of diffusive phase transformations during the austenitizing process in hypoeutectoid Fe-C steels, a two-dimensional model has been developed. The diffusion equations are solved within each phase (α and γ) using an explicit finite volume technique formulated using a square grid. The discrete α/γ interface is represented by special volume elements α/γ. The result showing the dissolution of ferrite particles in the austenite matrix are presented at different stages of the phase transformation. Specifically, the influence of the microstructure scale and heating rate on the transformation kinetics has been investigated. Final austenitization temperature calculated with this 2D model is compared with predictions of a simpler one dimensional (1D) front-tracking calculation.
Finite Element Study on Chip Formation and Force Response in Two-Dimensional Orthogonal Cutting of Rock
Authors: Che Demeng , Han Peidong , Peng Bo , Ehmann Kornel F.
Published: October 2014

The understanding of the rock-cutter interaction is essential for efficient rock cutting/drilling performed with polycrystalline diamond compact (PDC) cutters in petroleum engineering and gas exploration. Finite element modeling of the rock cutting process still remains a challenge due to the complex material properties of rock, rock fracture and chip formation phenomena and large force oscillations during the dominant brittle cutting mode. A finite element study was conducted to investigate the chip formation and force responses in two-dimensional orthogonal cutting of rock. The Drucker-Prager model that incorporates a simple shear strain failure criterion was exploited to simulate the interactions between the rock and the cutter. A fully instrumented rock cutting testbed was developed to enable the measurements of the three orthogonal force components and of the uni-axial acceleration in the cutting direction along rectilinear tool-paths to evaluate the simulation results. The chip formation phenomena and force response predictions derived by the FEM simulations were in good agreement with the experimental tests.
Multi-Scale Finite Element Modeling of Alumina Ceramics Undergoing Laser-Assisted Machining
Authors: Dong Xiangyang , Shin Yung C.
Published: October 2014

Alumina ceramics, due to their excellent properties of high hardness, corrosion resistance and low thermal expansion coefficient, are important industrial materials with a wide range of applications, but these materials also present difficulty in machining with low material removal rates and high tool wear. This study is concerned with laser-assisted machining (LAM) of high weight percentage of alumina ceramics to improve the machinability by a single point cutting tool while reducing the cutting forces. A multi-scale model is developed for simulating the machining of alumina ceramics. In the polycrystalline form, the properties of alumina ceramics are strongly related to the glass interface existing in their microstructure, particularly at high temperatures. The interface is characterized by a cohesive zone model (CZM) with the traction-separation law while the alumina grains are modeled as continuum elements with isotropic properties separated by the interface. Bulk deformation and brittle failure are considered for the alumina grains. Molecular dynamics (MD) simulations are carried out to obtain the atomistic structures and parameterize traction-separation laws for the interfaces of different compositions of alumina ceramics at high temperatures. The generated parameterized traction-separation laws are then incorporated into a finite element model in Abaqus to simulate the intergranular cracks. For validation purposes, simulated results of the multi-scale approach are compared with the experimental measurements of the cutting forces. The model is successful in predicting cutting forces with respect to the different weight percentage and composition of alumina ceramics at high temperatures in LAM processes.
High Production Rate Synthesis of CdS Nanoparticles Using a Reverse Oscillatory Flow Method
Authors: Peterson Daniel A. , Padmavathi C. , Paul Brian K.
Published: October 2014

A reverse oscillatory flow (ROF) mixing system is discussed having a reaction channel 460 μm high by 152 mm wide for high flow rate processing of nanoparticle chemistries. The ROF system is demonstrated to produce CdS nanoparticles at a production rate of 115.7 g/hour with a coefficient of variation for particle size down to 19%. These production rates are substantially higher than those achieved using other microchannel mixers while maintaining comparable size distributions. Advantages of the ROF approach include the use of larger microchannels which make the reactor easier to fabricate and less vulnerable to clogging.
Monitoring the Parameter Effects of Surface Grinding Process Using Temperature, Acoustic Emission and Force Measurement
Authors: Yin Guoxu , Nisal Tejas , Marinescu Ioan D. , Bugtai Nilo T.
Published: October 2014

Temperature, forces and acoustic emission measurements are employed for research into the mechanics of grinding and for process monitoring. Temperature measurement in grinding presents a number of challenges especially in wet grinding. Fluid can affect the precision of the measurement when using infrared technique or make a short circuit when using grindable thermocouple. This paper highlights the previous temperature measurement methods and introduces a new one for measuring. Acoustic Emission technique has the capability to provide efficient real-time knowledge and monitoring of the grinding process. AERMS values were used to analyses the process characteristics. This paper explores the relations between temperature, force, acoustic emission and roughness.
Predictive Force Modeling in MQL (Minimum Quantity Lubrication) Grinding
Authors: Shao Yamin , Liang Steven Y.
Published: October 2014

Using grinding fluid is the most common strategy to generate cooling and lubrication during the grinding process. However, economic and environmental drawbacks have been noticed for conventional flood cooling. MQL, which is to apply minimum amount of lubricant directly into the contact zone, is an alternative to deal with those concerns. In order to advance the MQL technique into practical manufacturing situations, understanding of the process and evaluation of the performance is necessary. This paper presents the predictive modeling of MQL grinding force through considerations of boundary lubrication condition, single grit interaction, wheel topography, material properties, and dynamic effects. The friction coefficient was first calculated based on boundary lubrication theory. Subsequently, the single grit interaction is studied considering both chip formation and ploughing mechanisms. Then the undeformed chip thickness distribution and dynamic grit density has been calculated for extrapolating the single grit interaction to the whole wheel. Finally, the predicted tangential and normal forces were presented and compared to surface grinding experiment data.
Exploration of a New Approach for Calibrating Grinding Power Model
Authors: Shi Zhongde , Guo Changsheng , Attia Helmi
Published: October 2014

This paper is concerned with the reliable calibration of the grinding power model. The power model used in the present paper is expressed by formulae with grinding parameters as input arguments, and a number of model constants representing a given wheel, workpiece, and grinding fluid combination. The model constants are calibrated using measured grinding forces and power, taking into consideration of the chip formation, sliding, and plowing components of the power. These correspond to the constants of specific chip formation energy uch, the coefficient of friction μ and average contact pressure pa, and the plowing force per unit width F′pl, respectively. A new generalized experimental approach was developed in this study to reflect the physical meaning of the model. Compared with other approaches, this approach does not require a pre-knowledge of the wheel wear flat area value and the regime of the average contact pressure. The proposed approach includes measurements of forces and power from surface grinding tests with a fixed set of grinding parameters conducted at different wheel dullness levels for calibrating the constant μ, as well as tests with variable workspeeds at each of the wheel dullness level for calibrating the other constants. As an application example, it was applied to calibrating the power model for grinding of a nickel-based alloy with oil as grinding fluid and electroplated CBN wheels. The calibrated model was then validated through tests under different grinding conditions.
Experimental Study on Friction Stir Welding of Dissimilar Al 6061 to Trip 780/800 Steel
Authors: Liu Xun , Lan Shuhuai , Ni Jun
Published: October 2014

Friction stir welding (FSW) of dissimilar Al 6061 and TRIP 780/800 steel has been performed under different process parameters, including tool rotational speed, welding speed as well as the relative position of the tool axis to the abutting edge. Temperature and mechanical welding force was recorded during the process. Welding speed has an insignificant effect on either the maximum temperature or welding force. However, it can directly change the length of high temperature duration, which will accordingly influence temperature distribution in the weld and the microstructure. Higher rotational speed can effectively elevate weld temperature through greater amount of heat input. Metallurgical observations on weld cross sections perpendicular to the joint line was performed using both optical and scanning electron microscope. Microstructure evolution was analyzed and related to the force and temperature measurement results during the FSW process.
An Investigation of the Effect of Nitrogen Phase on Cryogenic Machining Performance and a Case Study on Machining of Inconel 718 Alloy
Authors: Pusavec Franci , Courbon Cedric , Rech Joel , Kopac Janez , Jawahir I. S.
Published: October 2014

Sustainable manufacturing trends dictate the need for cleaner processes that are environmentally benign and with no adverse health effects. Cryogenic machining in recent times has emerged as such an effective and clean manufacturing process. In this field, a strong collaboration among partnering researches in the EU and US has been established. Prior research has proven that cooling effect in such sustainable machining operation is significant, while the lubrication effect is still either marginal or questionable. The nitrogen phase that is delivered to the cutting zone has a significant effect on this. The constant phase of the delivered fluid is first necessary condition to avoid the occurrence of thermal shocks. The first step in this direction for phase control is to be able to sense and accurately quantify the phase of the cryogenic fluid at the delivery. Therefore, this paper aims at presenting new experimental results on the use of a novel optical nitrogen phase sensor from the investigation of its robustness and response time. Additionally, a case study has been performed to show how the nitrogen phase affects the tribological properties of Inconel 718 alloy against a carbide tool. To examine this, experiments have been performed with a specially designed open tribometer to characterize the macroscopic friction coefficient and heat partition coefficient in the contact surface versus sliding velocity. Also, a simplified FEM model of cryogenic machining has been constructed to simulate the behavior of the machining process when delivering different phases of nitrogen. The delivered cryogenic fluid has been characterized in gas and liquid phases. It has been shown that liquid nitrogen can improve friction conditions more efficiently than gas phase nitrogen. Liquid phase has in general lower temperature and more dominant capability for heat evacuation and better lubrication properties than the gas phase, with the novel sensor being shown as capable of robustly characterizing the phase of the cryogenic fluid in the delivery itself.
Sub-Surface Crack Analysis for Diamond Slurry Lapping of Sapphire Wafers
Authors: Chen Chao-Chang A. , Tu Wei-Kang , Yang Jyun-Kai
Published: October 2014

Sapphire or mono-crystalline aluminum oxide wafers have been popularly adopted as the substrates of epi-layer process for the rapid growing demands of high-brightness light emitting diode (HB LED) industry. The HB LED devices for solid-state illumination have attracted immerse investigation of sub-surface crack problem induced in sapphire wafer processing. The diamond lapping has been recognized as a critical process for affecting the final polishing of sapphire wafers. This paper is to investigate the sub-surface damage layer induced by the diamond slurry lapping processes of sapphire wafers with two kinds of benchmark diamond slurries with different properties. All test wafers have been measured by dial gauge to observe the variation of thickness first and then the surface topography and subsurface properties have been inspected by coherence interferometer, CCI-Lite (Taylor Hobson, UK) instrument and then dual-focus focused ion beam, FIB (FEI Quanta 3D FEG) for sub-surface crack observation. The diamond slurry is composed with diamond abrasive grits and carrier for lapping with resin copper grooved plate. In this study, two slurries are noted as F and S both with the nominal diamond grit size 3 micron. The carriers are glycol based with viscosity ranged around 20 cP in room temperature and the viscosity-temperature plots have been measured for such slurry. Experimental results have shown that the 3D average surface roughness, Sa is obtained as 9.12 nm for sapphire wafer lapped by F slurry and as 6.63 nm lapped by S slurry. Thus the relationship of particle size distribution (PSD) of diamond grits and also the viscosity-temperature effect can be considered as key factors to MRR and surface quality of diamond lapping process of sapphire wafers. The sub-surface cracks can then be observed by FIB instrument and then quantified to evaluate the effects of diamond lapping process in order to shorten the further polishing time.
Multiaxial Stress Tests on Lightweight Materials in Support of Material Modeling and Accurate Sheet Forming Simulations
Authors: Kuwabara Toshihiko
Published: October 2014

This presentation is a review of mechanical test methods for accurately measuring the anisotropic plastic deformation behavior of metal sheets and tubes subjected to multiaxial stress states. Special attention is given to the measurement and modeling of the anisotropic plastic deformation behavior of lightweight metals commonly used in industry and to the validation of the material models based on anisotropic yield functions for large plastic strain ranges. The effects of the material models used in the metal forming simulations on the improvement of the predictive accuracy for forming defects are also discussed.
Simulation-Based Optimization of Electricity Demand Response for Sustainable Manufacturing Systems
Authors: Cuyler Leah , Sun Zeyi , Li Lin
Published: October 2014

Electricity demand response is considered a promising tool to balance the electricity demand and supply during peak periods. It can effectively reduce the cost of building and operating those peaking power generators that are only run a few hundred hours per year to satisfy the peak demand. The research on the electricity demand response implementation for residential and commercial building sectors has been very mature. Recently, it has also been extended to the manufacturing sector. In this paper, a simulation-based optimization method is developed to identify the optimal demand response decisions for the typical manufacturing systems with multiple machines and buffers. Different objectives, i.e. minimizing the power consumption under the constraint of system throughput, and maximize the overall earnings considering the tradeoff between power demand reduction and potential production loss, are considered. Different energy control decisions are analyzed and compared regarding the potential influence on the throughput of manufacturing system due to the different control actions adopted by throughput bottleneck machine.
A Novel Multi-Material Additive Manufacturing Technique for Fabricating Laminated Polymer Nanocomposite Structures
Authors: Spackman Clayson , Picha Kyle , Gross Garrett G. , Nowak James F. , Smith Phil J. , Zheng Jian , Samuel Johnson , Mishra Sandipan
Published: October 2014

The objective of this research is to develop a novel, multi-material additive manufacturing technique for fabricating laminated polymer nancomposite structures that have characteristic length-scales in the tens of millimeters range. The 3D printing technology presented in this paper combines the conventional inkjet-based printing of ultraviolet (UV) curable polymers with the deposition of either aligned or random nano-scale fiber mats, in between each printed layer. The fibers are first generated using an electrospinning process that produces the roll of fibers. These fibers are then transferred to the part being manufactured using a stamping operation. The process has been proven to manufacture multi-material laminated nanocomposites having different 3D geometries. The dimensional accuracy of the parts is seen to be a function of the interaction between the different UV-curable polymer inks. In general, the addition of the nanofibers in the form of laminates is seen to improve the mechanical properties of the material, with the Young’s modulus and the ultimate breaking stress showing the most improvement. The pinning and deflection of micro-cracks by the nano-scale fiber mats has been identified to be the underlying mechanism responsible for these improved mechanical properties. The thermogravimetric analysis reveals that these improvements in the mechanical properties are obtained without drastically altering the thermal degradation pattern of the base polymer.
Microstructure-Based 3D FE Modeling for Micro Cutting Ferritic-Pearlitic Carbon Steels
Authors: Abouridouane M. , Klocke F. , Lung D.
Published: October 2014

The mechanics of the cutting process on the microscopic level differ fundamentally from the conventional macro cutting. For example, the tool edge radius influences the cutting mechanism in micro machining significantly with regard to the effective rake angle, the minimum chip thickness, the dominance of ploughing, and the related elasto-plastic deformation of the workpiece material. These phenomena, known as size effects, have a profound impact on the cutting force, process stability, and resulting surface finish in micro cutting. Therefore, microstructural effects in microscale cutting require quite different assumptions to be made concerning underlying material behaviour during micro cutting and have led to the need for new modeling approaches to account for such effects.

This paper presents a three-dimensional finite element approach to incorporate microstructure into micro cutting simulation based on the concept of a representative volume element (RVE) and constitutive material modeling as well as using the Lagrangian formulation proposed in the implicit FE code Deform 3D™. Micro drilling and micro milling tests using solid carbide tools with different diameters (d = 50 μm − 1 mm) were performed on ferrite-pearlite two-phase steel AISI 1045 for the verification of the developed 3D multiphase FE computation model regarding chip formation, feed force, and torque. The developed 3D multiphase FE model was successfully used to predict size effects in micro cutting.
Surface Integrity Studies in Ball End Milling of Thin Shaped Cantilever Inconel 718
Authors: Bhopale Nandkumar N. , Pawade Raju S.
Published: October 2014

The paper presents the surface integrity analysis in ball end milling of thin shaped cantilever plate of Inconel 718. It is noticed that the workpiece deflection has significantly contributed to machined surface integrity in terms of surface topography and subsurface microhardness. The ball end milling performed with 15° workpiece inclination with horizontal tool path produced higher surface integrity which varies with the location of machined surface region. In general, the mid portion of the machined plate shows lower surface roughness and microhardness with less surface defects.
Development Status of Cloud Manufacturing in China
Authors: Zhang Lin , Mai Jingeng , Tao Fei , Luo Yongliang , Ren Lei
Published: October 2014

Facing technological innovation and structural transformation challenges in depth development of China’s manufacturing industry, the concept of cloud manufacturing (CMfg) was proposed and got government’s support. This paper reviews the development status of CMfg in China. On the one hand, a number of research institutions studied systematically on theories and key technologies of CMfg, such as application patterns and platform architectures, resource matching, service composition and sharing, manufacturing cloud integrated management, etc. And on the other hand, some cloud manufacturing service platforms were build and applied in small and medium-sized enterprises and group enterprises, such as group enterprise CMfg service platform for the complicated aerospace products, CMfg service platform of aerospace technology group, group enterprise CMfg service platform for manufacturing and management, cloud application in growing enterprise management informatization, CMfg service platform for mould and flexible material industry, CMfg service platform for new product R&D of car parts, CMfg service platform for steel industry chain collaboration, CMfg service platform for mould industry in Ningbo, etc.
Optimal Machining Parameter Selection Based on Real-Time Machine Monitoring Using IEC 61499 Function Blocks for Use in a Cloud Manufacturing Environment: A Case Study for Face Milling
Authors: Tapoglou Nikolaos , Mehnen Jörn , Doukas Michael , Mourtzis Dimitris
Published: October 2014

Optimization of manufacturing processes is one of the key challenges towards a sustainable manufacturing environment. The components manufactured nowadays are usually divided into small batches of highly customized parts. These parts are usually machined using the traditional approach for machining on CNC machines. This approach involves the creation of a static G-code for every component that is manufactured, which is dispatched to the machines either manually or through a LAN network. In this paper a new approach in machine tool programming is presented. The proposed system is based on IEC 61499 function blocks to create last-minute feature based code for machining respecting actual machine status. The proposed system optimizes cutting parameters and delivers optimized code with respect to machining time. The function block approach is ideal for on-controller implementation while also allowing through its web based option the embedding into a cloud manufacturing environment. A cloud platform accommodates the machine availability monitoring module for increasing shop-floor awareness and allowing for the correct decisions at the right time. The machining process of face milling was selected as a case study for demonstrating the functionality of the proposed system. The results of the case study are visualized and verified using simulation software.
Optimal Machining Parameter Selection in Titanium Milling Using a Decision Analytic Framework
Authors: Karandikar Jaydeep , Tyler Chris , Abbas Ali , Schmitz Tony
Published: October 2014

The paper presents a decision analytic framework for optimal machining parameter selection in titanium milling, considering uncertainty in tool life and stability. An influence diagram showing the decision situation, the corresponding uncertainties and the value was developed. The objective was to select optimum machining parameters to minimize machining cost while considering uncertainty in tool life and stability. The uncertainties were characterized using a probability distribution taking into account all available information. The cost associated with tool failure and unstable cutting conditions was incorporated in the cost formulation. A process probability tree showing the uncertainties and the corresponding costs was constructed. The optimal machining parameters were selected which minimize the expected machining cost. Results show a 90% reduction in machining cost as compared to manufacturer recommended parameters. A discussion section regarding inference and experimental design is included.
Evaluating the Performance of Current Self-Pierce Rivet Technology for the Joining of High Strength Steel and Aluminum Alloys
Authors: Van Hall S. N. , Findley K. O. , Campbell A. M.
Published: October 2014

The performance of a current self-pierce rivet (SPR) alloy, 10B37 boron steel, at commercial processing conditions has been evaluated in two case studies; the joining of USIBOR 1500 high strength steel to heat-treated 6000 series aluminum and the utilization of standard rivet and die combinations to join multiple different sheet metal stack ups. The mechanical properties of the rivet and related wire (raw material) were also assessed over the commercial automotive hardness range to draw correlations between rivet performance and material properties. Analysis of the rivet failures from attempts to join USIBOR 1500 to 6000 series aluminum indicated rivets with hardness values below 550 HV exhibited buckling of the rivet legs and rivets with hardness values above 550 HV developed fractures at the tail of the rivet. The fractures were consistent with those observed when attempting to join an alternate sheet metal stack up with a standard rivet and die combination. These fractures most likely form as a result of a hoop stress that develops at the rivet tail during flaring into the bottom substrate. It is inferred that embrittlement at prior austenite grain boundaries contributes to the formation of these fractures in rivets with hardness values in excess of 550 HV, causing limited performance in tension and the development of fractures along the circumference of the rivet after insertion. In order to provide satisfactory joining of these two different joining scenarios, an alternate alloy must be employed for use as a self-pierce rivet which has higher ductility than the current alloy at the strength levels required to prevent buckling of the rivet legs.
A Feature Based Method for Product-Oriented Representation to Manufacturing Resources in Cloud Manufacturing
Authors: Liu Xu , Li Yingguang , Wang Wei , Wang Lihui
Published: October 2014

In cloud manufacturing, resources are encapsulated into manufacturing services to be provided in the manufacturing cloud. Resources representation is the basis for resources encapsulation. However, traditional representation methods to manufacturing resources mainly focus on the static description and/or current status of equipment. Research in product-oriented representation to manufacturing capabilities is limited. As a result, the evaluation to resources in the manufacturing cloud is indirect which will complicate the decision making in service determination. This paper presents a feature based method for manufacturing resources representation. Machining features will be first extracted from the part model based on a predefined feature category. Then capabilities of resources linked by the manufacturing cloud to machine the part will be generated by computing the capabilities to machine the features based on a knowledge base composed of the rules to define resource capabilities. With this method, capabilities of manufacturing resources will be associated with certain product and the selection of service from the manufacturing cloud will be greatly facilitated.
Relationship Between Implementation of TQM, JIT, TPM and SCM and Manufacturing Performance: Empirical Evidences From Indian Context
Authors: Wakchaure V. D. , Nandurkar K. N. , Kallurkar S. P.
Published: October 2014

Earlier empirical studies on joint implementation of different combinations of Total Quality Management (TQM), Just-in-Time (JIT), Total Productive Maintenance (TPM), and Supply Chain Management (SCM) concluded that the high performing manufacturing plants have implemented practices from more than one manufacturing program. All these programs are complementary in nature. However, there is no study that provides empirical examination of TQM, JIT, TPM and SCM within single framework and broader perspective is missing. In this paper ‘Integrated Manufacturing Practices’ framework is presented based on synergistic relationship among TQM, JIT, TPM and SCM. The data of 155 manufacturing plants in India is analyzed using Discriminant Analysis (DA). The result of the analysis shows that the practices from each of the paradigm has significant loading on each of the performance measure. The findings demonstrate the importance of implementing the TQM, JIT, TPM and SCM synergistically to enhance overall performance of the manufacturing plants.
Review: Dimensional Accuracy in Additive Manufacturing Processes
Authors: Lee Pil-Ho , Chung Haseung , Lee Sang Won , Yoo Jeongkon , Ko Jeonghan
Published: October 2014

This paper reviews the state-of-the-art research related to the dimensional accuracy in additive manufacturing (AM) processes. It is considered that the improvement of dimensional accuracy is one of the major scientific challenges to enhance the qualities of the products by AM. This paper analyzed the studies for commonly used AM techniques with respect to dimensional accuracy. These studies are classified by process characteristics, and relevant accuracy issues are examined. The accuracies of commercial AM machines are also listed. This paper also discusses suggestions for accuracy improvement. With the increase of the dimensional accuracy, not only the application of AM processes will diversify but also their value will increase.
Effect of Paste Properties on Extrudate Freezing Time in Freeze-Form Extrusion Fabrication Processes
Authors: Li Mingyang , Landers Robert G. , Leu Ming C.
Published: October 2014

During the freeze–form extrusion fabrication process for aqueous–based pastes, the sub–zero temperature environment aids the part in maintaining its shape by freezing the water present in the paste. However, while some pastes can be frozen properly, other pastes using the same extrusion strategy may be kept in semi–liquid state and cause the part to deform or even collapse. Therefore, different dwell times are needed between layers for different pastes, which may substantially increase part build time. In this paper, a simplified one–dimensional model was developed and validated by the commercial code Fluent. The paste temperature and paste freezing time were computed for various process parameters via numerical simulation using this model. As the layer number increases, the paste freezing time reaches a steady state. The relationship between the steady state freezing time and the paste material and solids loading was studied. The simulations show the paste freezing time decreases due to the increase in paste thermal conductivity, solids loading and total time between layers.