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1

An Approach to Optimize Size Parameters of Forging by Combining Hot-Processing Map and FEM  

NASA Astrophysics Data System (ADS)

The size parameters of 6061 aluminum alloy rib-web forging were optimized by using hot-processing map and finite element method (FEM) based on high-temperature compression data. The results show that the stress level of the alloy can be represented by a Zener-Holloman parameter in a hyperbolic sine-type equation with the hot deformation activation energy of 343.7 kJ/mol. Dynamic recovery and dynamic recrystallization concurrently preceded during high-temperature deformation of the alloy. Optimal hot-processing parameters for the alloy corresponding to the peak value of 0.42 are 753 K and 0.001 s-1. The instability domain occurs at deformation temperature lower than 653 K. FEM is an available method to validate hot-processing map in actual manufacture by analyzing the effect of corner radius, rib width, and web thickness on workability of rib-web forging of the alloy. Size parameters of die forgings can be optimized conveniently by combining hot-processing map and FEM.

Hu, H. E.; Wang, X. Y.; Deng, L.

2014-11-01

2

Large forging manufacturing process  

DOEpatents

A process for forging large components of Alloy 718 material so that the components do not exhibit abnormal grain growth includes the steps of: a) providing a billet with an average grain size between ASTM 0 and ASTM 3; b) heating the billet to a temperature of between 1750.degree. F. and 1800.degree. F.; c) upsetting the billet to obtain a component part with a minimum strain of 0.125 in at least selected areas of the part; d) reheating the component part to a temperature between 1750.degree. F. and 1800.degree. F.; e) upsetting the component part to a final configuration such that said selected areas receive no strains between 0.01 and 0.125; f) solution treating the component part at a temperature of between 1725.degree. F. and 1750.degree. F.; and g) aging the component part over predetermined times at different temperatures. A modified process achieves abnormal grain growth in selected areas of a component where desirable.

Thamboo, Samuel V. (Latham, NY); Yang, Ling (Niskayuna, NY)

2002-01-01

3

Impedance analysis of forging process and strategy study on compliance for forging manipulator  

NASA Astrophysics Data System (ADS)

In the field of heavy forging, there are numerous researches on deformation rule in forging process by FEM simulation, however, not many scholars take the equipment constraint and the mutual reaction load between the forging manipulator clamp and the forging blank into account, which will impact on safety of manipulator body and quality of forging blank. This paper presents an impedance model to describe the load and formulates compliance strategies correspondingly to reduce the mutual reaction load for forging manipulator. Firstly, an FEM model of forging process is built. Meanwhile, the clamp of forging manipulator is added to the model as movement constraint and interaction part between the manipulator and the forming process. Secondly, a typical forging process is simulated by changing the movement constraint, and then an impedance model is established to describe the relationship between the load and movement constraint. Finally, two kinds of compliance strategies are formulated according to the impedance model, one is called free compliance, and the other is initiative/passive compliance. The simulation results show that compliance strategies reduce the load amounting to 5 000 kN in z direction between the manipulator clamp and the forging blank obviously, which may lead to serious accidents, such as the capsizing of forging manipulator, the fracture of manipulator clamp, and so on. The proposed research simulates the more real forging process, gets the initiative/passive compliance strategy which is more simple and suitable to the real producing and better for forming a forging process planning and control system in the modern production, and improves the quality and efficiency of heavy forging.

Zhang, Pu; Yao, Zhenqiang; Du, Zhengchun

2013-07-01

4

Simulation and analysis of hot forging process for industrial locking gear elevators  

NASA Astrophysics Data System (ADS)

In this paper hot forging process for industrial locking gear elevators is simulated and analyzed. An increase in demand of industrial locking gear elevators with better quality and lower price caused the machining process to be replaced by hot forging process. Production of industrial locking gear elevators by means of hot forging process is affected by many parameters such as billet temperature, geometry of die and geometry of pre-formatted billet. In this study the influences of billet temperature on effective plastic strain, radius of die corners on internal stress of billet and thickness of flash on required force of press are investigated by means of computer simulation. Three-dimensional modeling of initial material and die are performed by Solid Edge, while simulation and analysis of forging are performed by Super Forge. Based on the computer simulation the required dies are designed and the workpieces are formed. Comparison of simulation results with experimental data demonstrates great compatibility.

Maarefdoust, M.; Kadkhodayan, M.

2010-06-01

5

Microstructural Evaluation of Forging Parameters for Superalloy Disks  

NASA Technical Reports Server (NTRS)

Forgings of nickel base superalloy were formed under several different strain rates and forging temperatures. Samples were taken from each forging condition to find the ASTM grain size, and the as large as grain (ALA). The specimens were mounted in bakelite, polished, etched and then optical microscopy was used to determine grain size. The specimens ASTM grain sizes from each forging condition were plotted against strain rate, forging temperature, and presoak time. Grain sizes increased with increasing forging temperature. Grain sizes also increased with decreasing strain rates and increasing forging presoak time. The ALA had been determined from each forging condition using the ASTM standard method. Each ALA was compared with the ASTM grain size of each forging condition to determine if the grain sizes were uniform or not. The forging condition of a strain rate of .03/sec and supersolvus heat treatment produced non uniform grains indicated by critical grain growth. Other anomalies are noted as well.

Falsey, John R.

2004-01-01

6

Prediction of Final Material State in MultiStage Forging Processes  

Microsoft Academic Search

Multi-stage forging processes are used to manufacture reservoirs for high pressure hydrogen and tritium storage. The warm-forging process is required to produce required macro and microscale forged material properties of 304 and 21-6-9 stainless steel. Strict requirements on the forged material strength, grain size and grain flow are necessitated to inhibit the diffusion of gas which inevitably leads to material

Michael L. Chiesa; Arthur A. Brown; Bonnie R. Antoun; Jakob T. Ostien; Richard A. Regueiro; Douglas J. Bammann; Nancy Y. Yang

2004-01-01

7

Process modelings and simulations of heavy castings and forgings  

NASA Astrophysics Data System (ADS)

The Materials Process Modeling Division, IMR, CAS has been promoting for more than 10 years research activities on modeling and experimental studies on heavy castings and forgings. In this report, we highlight some selected achievements and impacts in this area: To satisfy domestic strategic requirements, such as nuclear and hydraulic power, marine projects and high speed rail, we have developed a number of casting and forging technologies, which combine advanced computing simulations, X-ray real time observation techniques and industrial-scaled trial experiments. These technologies have been successfully applied in various industrial areas and yielded a series of scientific and technological breakthroughs and innovation. Important examples of this strategic research include the hot-processing technologies of the Three Gorge water turbine runner, marine crankshaft manufacturers, backup rolls for hot rolling mills and the production of hundreds-ton steel ingot.

Li, Dianzhong; Sun, Mingyue; Wang, Pei; Kang, Xiuhong; Fu, Paixian; Li, Yiyi

2013-05-01

8

Simulation Of Phase Transformation In Hot Forging Dies During A Precision Forging Process By Means Of Finite-Element-Analysis  

NASA Astrophysics Data System (ADS)

The Finite-Element-Analysis (FEA) is of major importance for the design and improvement of forging processes. In this field, FEA is traditionally used to predict die fill, residual stresses and forming forces. The intention of the work presented in this paper is the development of an advanced simulation model for the description of phase transformation processes in forging dies based on FEA. This simulation model enables the prediction of die wear, since the hardness of the surface layer could be predicted. Due to the mechanical and thermal interactions with the work piece, the temperature in certain regions of the die surface layer exceeds the austenitizing (Ac1b) temperature. After the lubrication, following the forging cycle, a fast cooling of the die surfaces takes place, so that martensite is generated in the surface layer. Below this layer, the temperature is higher than the annealing one, but lower than the Ac1b temperature of the forging die steel, which leads to soft annealing of this region. A precision forging process will be simulated to predcit this change of microstructure. The FEA includes the modelling of mechanical and thermal interactions between the work piece and the dies and the cooling through a lubrication medium. Finally, in order to calculate the microstructure, specific developed subroutines are implemented in a commercial FE-code.

Doege, E.; Behrens, B.-A.; Schaefer, F.

2004-06-01

9

Numerical simulation and experimental study for the die forging process of a high-speed railway brake disc hub  

NASA Astrophysics Data System (ADS)

With the aim of manufacturing a near-net shape forging product of a brake disk hub for the high-speed railway, the die forging process was designed and optimized in this study. Firstly, based on the measured stress-strain curves at different strain rates and the thermal-physical parameters of 40Cr A steel, a finite element model for the forging process of a high-speed railway brake disc hub was established. Then, the temperature, stress and strain fields were studied and analyzed at the pre-forging and the finial-forging stages. Besides, in order to trace the stress and strain evolution, five points at different positions were chosen on the billet, and the comparison of the state conditions was made among these points. The results have demonstrated that the product can be well formed by an elaborately designed three-stage forging process, which may reduce the metal machine allowance and the producing cost effectively. Finally, an industrial trial was made and a machined product with sound quality was obtained.

Sun, Mingyue; Xu, Bin; Zhang, Long; LI, Dianzhong

2013-05-01

10

First Results of Energy Saving at Process Redesign of Die Forging Al-Alloys  

NASA Astrophysics Data System (ADS)

The contribution deals with eco-friendly solutions for shortened production chains of forging light alloys. During the die forging operations a remarkable amount of material goes into the flash and later on into chips during finish machining. These low value side products are rich with embedded energy therefore recycling or reprocessing could be very energy saving procedure. In cooperation with a die forging company a shortened reprocessing cycle has been studied starting from re-melting the forging flash and without additional heating to cast preforms for subsequent die forging. As such preforms have not as good formability characteristics as those done from extruded billets the isothermal forging process has been adopted. First results showed that without cracks and other defects the formability is sufficient for a broad spectrum of forgings. To improve the formability a homogenization process of cast preforms has been implemented. As the process started immediately after casting, amount of additional energy for heating was minimized. To reduce voids forging process was redesigned in a way to assure greater hydrostatic pressures in parts during forging. First results were promising therefore research is going towards improving processes without adding significantly more energy as it is needed for casting with homogenization and die forging.

Pepelnjak, Tomaž; Kuzman, Karl; Kokol, Anton

2011-05-01

11

First Results of Energy Saving at Process Redesign of Die Forging Al-Alloys  

SciTech Connect

The contribution deals with eco-friendly solutions for shortened production chains of forging light alloys. During the die forging operations a remarkable amount of material goes into the flash and later on into chips during finish machining. These low value side products are rich with embedded energy therefore recycling or reprocessing could be very energy saving procedure.In cooperation with a die forging company a shortened reprocessing cycle has been studied starting from re-melting the forging flash and without additional heating to cast preforms for subsequent die forging. As such preforms have not as good formability characteristics as those done from extruded billets the isothermal forging process has been adopted. First results showed that without cracks and other defects the formability is sufficient for a broad spectrum of forgings.To improve the formability a homogenization process of cast preforms has been implemented. As the process started immediately after casting, amount of additional energy for heating was minimized. To reduce voids forging process was redesigned in a way to assure greater hydrostatic pressures in parts during forging. First results were promising therefore research is going towards improving processes without adding significantly more energy as it is needed for casting with homogenization and die forging.

Pepelnjak, Tomaz; Kuzman, Karl [Faculty of Mechanical Engineering, Askerceva 6, SI-1000 Ljubljana (Slovenia); Kokol, Anton [Kovinar-forging company, Kovaska cesta 12, SI-3205 Vitanje (Slovenia)

2011-05-04

12

Quality of Simulation Packages for Flashless Hot Forging Operations  

Microsoft Academic Search

The development of new forming processes in the field of hot forging technology includes many difficulties due to the large number of parameters constituting the process. By developing a process the design engineer has to consider both technical and economical limits in order to obtain competitive forgings. Pre- ferred process parameters include small number of forging steps, less tool abrasion,

Hans Christoph Altmann; Wim J. Slagter

13

Forging Advisor  

SciTech Connect

Many mechanical designs demand components produced to a near net shape condition to minimize subsequent process steps. Rough machining from slab or bar stock can quickly and economically produce simple prismatic or cylindrical shapes. More complex shapes can be produced by laser engineered net shaping (LENS), casting , or forging. But for components that require great strength in mission critical applications, forging may be the best or even the only option. However, designers of these parts may and often do lack the detailed forging process knowledge necessary to understand the impact of process details such as grain flow or parting line placement on both the forging process and the characteristics of the forged part. Economics and scheduling requirements must also be considered. Sometimes the only viable answer to a difficult problem is to re-design the assembly to reduce loading and enable use of other alternatives.

Kerry Barnett

2003-03-01

14

Study of Residual Stresses in the Barrel Processed by the Radial Forging  

Microsoft Academic Search

When the gun fires in rapid firing rate, serious factors such as the high ambient temperatures, thermal transients and corrosive-erosive environment existing at the bore surface limit the barrel life. Therefore, most of the current gunpsilas rifling is produced by the radial forging process of the high-alloy steel. The residual stresses in the forged product directly affect the fatigue strength,

Liu Lili; Fan Lixia

2009-01-01

15

Approximate-model based estimation method for dynamic response of forging processes  

NASA Astrophysics Data System (ADS)

Many high-quality forging productions require the large-sized hydraulic press machine (HPM) to have a desirable dynamic response. Since the forging process is complex under the low velocity, its response is difficult to estimate. And this often causes the desirable low-velocity forging condition difficult to obtain. So far little work has been found to estimate the dynamic response of the forging process under low velocity. In this paper, an approximate-model based estimation method is proposed to estimate the dynamic response of the forging process under low velocity. First, an approximate model is developed to represent the forging process of this complex HPM around the low-velocity working point. Under guaranteeing the modeling performance, the model may greatly ease the complexity of the subsequent estimation of the dynamic response because it has a good linear structure. On this basis, the dynamic response is estimated and the conditions for stability, vibration, and creep are derived according to the solution of the velocity. All these analytical results are further verified by both simulations and experiment. In the simulation verification for modeling, the original movement model and the derived approximate model always have the same dynamic responses with very small approximate error. The simulations and experiment finally demonstrate and test the effectiveness of the derived conditions for stability, vibration, and creep, and these conditions will benefit both the prediction of the dynamic response of the forging process and the design of the controller for the high-quality forging. The proposed method is an effective solution to achieve the desirable low-velocity forging condition.

Lei, Jie; Lu, Xinjiang; Li, Yibo; Huang, Minghui; Zou, Wei

2015-03-01

16

Prediction of Final Material State in Multi-Stage Forging Processes  

NASA Astrophysics Data System (ADS)

Multi-stage forging processes are used to manufacture reservoirs for high pressure hydrogen and tritium storage. The warm-forging process is required to produce required macro and microscale forged material properties of 304 and 21-6-9 stainless steel. Strict requirements on the forged material strength, grain size and grain flow are necessitated to inhibit the diffusion of gas which inevitably leads to material embrittlement. Accurate prediction of the final material state requires modeling of each of the forging stages and tracking the material state evolution through each deformation and reheating stage. An internal state variable constitutive model, capable of predicting the high strain rate, temperature dependent material behavior, is developed to predict final material strength and microstructure. History dependent, internal state variables are used to model the isotropic and kinematic hardening, grain size and recrystallization. Numerical methodologies were developed to track and remap material state from one forging stage analysis to the next including the effects of relaxation during reheating. Multi-stage, uniaxial, compression tests were performed over a range of temperatures, strain rates, and strains to validate the constitutive model and methodology. Tensile specimens were taken from several forgings and compared to model predictions.

Chiesa, Michael L.; Brown, Arthur A.; Antoun, Bonnie R.; Ostien, Jakob T.; Regueiro, Richard A.; Bammann, Douglas J.; Yang, Nancy Y.

2004-06-01

17

1 INTRODUCTION The cold forging processes, including extrusion,  

E-print Network

, have been widely used to realize the net-shape manufacture in the transportation industry. The friction are generally coated with zinc phosphate and soap and lubricated with oil to reduce the friction during forging [1]. For reduction of the cost and time of manufacture, almost all of manufacturers and research

Paris-Sud XI, Université de

18

Automatic simulation of a sequence of hot-former forging processes by a rigid-thermoviscoplastic finite element method  

SciTech Connect

A fully automatic forging simulation technique in hot-former forging is presented in this paper. A rigid-thermoviscoplastic finite element method is employed together with automatic simulation techniques. A realistic analysis model of the hot-former forging processes is given with emphasis on thermal analysis and simulation automation. The whole processes including forming, dwelling, ejecting, and transferring are considered in the analysis model and various cooling conditions are embedded in the analysis model. The approach is applied to a sequence of three-stage hot former forging process. Nonisothermal analysis results are compared with isothermal ones and the effect of heat transfer on predicted metal flows is discussed.

Joun, M.S. [Gyeongsang National Univ., Chinju (Korea, Republic of). Dept. of Mechanical Engineering; Moon, H.K. [Hanwha Machinery Co., Changwon (Korea, Republic of). Research Center; Shivpuri, R. [Ohio State Univ., Columbus, OH (United States). Dept. of Industrial, Welding and Systems Engineering

1998-10-01

19

Vacuum-assisted rheo-forging process of A356 aluminum alloys  

Microsoft Academic Search

In recent years, various rheo-forming methods have been developed to produce products with improved mechanical properties. To this end, rheo-forging of metal offers not only superior mechanical strength but also requires much lower machine loads than solid forming processes. However, there are many problems, such as air indraft during the stirring of the molten metal as well as the expense

H. H. Kim; C. G. Kang

2008-01-01

20

Computer-assisted Rheo-forging Processing of A356 Aluminum Alloys  

SciTech Connect

Die casting process has been used widely for complex automotive products such as the knuckle, arm and etc. Generally, a part fabricated by casting has limited strength due to manufacturing defects by origin such as the dendrite structure and segregation. As an attempt to offer a solution to these problems, forging has been used as an alternative process. However, the forging process provides limited formability for complex shape products. Rheo-forging of metal offers not only superior mechanical strength but also requires significantly lower machine loads than solid forming processes. In order to produce semi-solid materials of the desired microstructure, a stirring process is applied during solidification of A356 aluminum molten state. This paper presents the results of an A356 aluminum alloy sample, which were obtained by experiment and by simulation using DEFORM 3D V6.1. Samples of metal parts were subsequently fabricated by using hydraulic press machinery. In order to compare the influence of loading method, two types of samples were fabricated: (1) samples fabricated under direct loading die sets (2) those fabricated under indirect loading die sets. The formability and defects, which were predicted by FEM simulation, were similar to those of samples used in practice.

Kim, H. H. [Department of Mechanical and Precision Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Kang, C. G. [School of Mechanical Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)

2010-06-15

21

Computer-assisted Rheo-forging Processing of A356 Aluminum Alloys  

NASA Astrophysics Data System (ADS)

Die casting process has been used widely for complex automotive products such as the knuckle, arm and etc. Generally, a part fabricated by casting has limited strength due to manufacturing defects by origin such as the dendrite structure and segregation. As an attempt to offer a solution to these problems, forging has been used as an alternative process. However, the forging process provides limited formability for complex shape products. Rheo-forging of metal offers not only superior mechanical strength but also requires significantly lower machine loads than solid forming processes. In order to produce semi-solid materials of the desired microstructure, a stirring process is applied during solidification of A356 aluminum molten state. This paper presents the results of an A356 aluminum alloy sample, which were obtained by experiment and by simulation using DEFORM 3D V6.1. Samples of metal parts were subsequently fabricated by using hydraulic press machinery. In order to compare the influence of loading method, two types of samples were fabricated: (1) samples fabricated under direct loading die sets (2) those fabricated under indirect loading die sets. The formability and defects, which were predicted by FEM simulation, were similar to those of samples used in practice.

Kim, H. H.; Kang, C. G.

2010-06-01

22

A filling analysis of the forging process of semi-solid aluminum materials considering solidification phenomena  

Microsoft Academic Search

A new forming technology has been developed to fabricate near-net shape products using light metal. Semi-solid forming technology has some advantages compared with conventional forming processes such as die casting, squeeze casting and hot\\/cold forging. In this study, the numerical analysis of semi-solid filling is carried out and corresponding experiments are undertaken for semi-solid materials (SSM) of solid fraction fS=30%

C. G Kang; J. S Choi; D. W Kang

1998-01-01

23

Searches for new alkylation catalysts, processes forge ahead  

SciTech Connect

As a result of the hazardous properties of hydrofluoric acid (HF), HF alkylation has been the subject of much recent controversy. The safety and environmental requirements associated with the HF alkylation processes continue to drive industry to develop new alkylation technologies. In fact, several major process licensors are well on their ways to bringing these new technologies to market. The new alkylation processes under development center around new, less-harmful catalysts. Although this work is progressing rapidly, an update of the status of some of these new processes will keep refiners abreast of the new options they may soon have for building new alkylation units or retrofitting existing ones. The process development and economics are described for a Topsoe/Kellogg fixed bed alkylation process and the Kerr-McGee homogeneous alkylation technology process.

Rhodes, A.

1994-08-22

24

Experimental and Numerical Investigation of Forging Process to Reproduce a 3D Aluminium Foam Complex Shape  

SciTech Connect

Metallic foams represent one of the most exciting materials introduced in the manufacturing scenario in the last years. In the study here addressed, the experimental and numerical investigations on the forging process of a simple foam billet shaped into complex sculptured parts were carried out. In particular, the deformation behavior of metallic foams and the development of density gradients were investigated through a series of experimental forging tests in order to produce a selected portion of a hip prosthesis. The human bone replacement was chosen as case study due to its industrial demand and for its particular 3D complex shape. A finite element code (Deform 3D) was utilized for modeling the foam behavior during the forging process and an accurate material rheology description was used based on a porous material model which includes the measured local density. Once the effectiveness of the utilized Finite Element model was verified through the comparison with the experimental evidences, a numerical study of the influence of the foam density was investigated. The obtained numerical results shown as the initial billet density plays an important role on the prediction of the final shape, the optimization of the flash as well as the estimation of the punch load.

Filice, Luigino; Gagliardi, Francesco; Umbrello, Domenico [Department of Mechanical Engineering, University of Calabria, P. Bucci, 87036 Rende (Serbia and Montenegro) (Italy); Shivpuri, Rajiv [Department of Industrial, Welding and System Engineering, Ohio State University, 1971 Neil Avenue, 210 Baker Systems, Columbus, OH 43210-1217 (United States)

2007-05-17

25

A Combined Radial Forging-Forward Extrusion Forming Process of Alternator Poles  

NASA Astrophysics Data System (ADS)

A combined radial forging-forward extrusion forming process of alternator poles is proposed based on an analysis of the structure of alternator poles as well as the forming die sets. First, a thick-bottom base of the alternator poles is obtained through radial forging. The middle boss and claw teeth are then formed through forward extrusion. A 3D coupled thermomechanical finite element model is employed. Billet deformation, metal flow, and forming load are obtained. The results show that the middle boss cavity is filled earlier and the process is no longer simultaneous extrusion during the second forming step. Then, the forming load increases sharply. An improved process that controls the metal flow in the middle boss cavity and aids in pushing the metal into the corners of the claw teeth cavity is proposed. The middle boss and claw teeth cavities can be filled simultaneously. The sharp increase of the forming load in the final forming stage is avoided. Simulative and experimental results show that the improved process can considerably reduce the final forming load to form a well-shaped product.

Yang, Cheng; Zhao, Shengdun; Zhang, Jianjun

2014-01-01

26

Development of Replacements for Phoscoating Used in Forging, Extrusion and Metal Forming Processes  

SciTech Connect

Many forging, extrusion, heading and other metal forming processes use graphite-based lubricants, phosphate coatings, and other potentially hazardous or harmful substances to improve the tribology of the metal forming process. The application of phosphate-based coatings has long been studied to determine if other synthetic ''clean'' lubricants could provide the same degree of protection afforded by phoscoatings and its formulations. So far, none meets the cost and performance objectives provided by phoscoatings as a general aid to the metal forming industry. In as much as phoscoatings and graphite have replaced lead-based lubricants, the metal forming industry has had previous experience with a legislated requirement to change processes. However, without a proactive approach to phoscoating replacement, many metal forming processes could find themselves without a cost effective tribology material necessary for the metal forming process

Kerry Barnett

2003-03-01

27

Advanced numerical models for the thermo-mechanical-metallurgical analysis in hot forging processes  

NASA Astrophysics Data System (ADS)

In the paper a literature review of the numerical modeling of thermo-mechanical-metallurgical evolutions of a metal in hot forging operations is presented. In particular models of multiaxial loading tests are considered for carbon steels. The collected examples from literature regard phases transformations, also martensitic transformations, morphologies evolutions and transformation plasticity phenomena. The purpose of the tests is to show the correlation between the mechanical and the metallurgical behavior of a carbon steel during a combination of several types of loads. In particular a few mechanical tests with heat treatment are analyzed. Furthermore, Ti-6Al-4V titanium alloy is considered. Such material is a multi-phasic alloy, at room temperature made of two main different phases, namely Alpha and Beta, which evolve during both cooling and heating stages. Several numerical applications, conducted using a commercial implicit lagrangian FEM code are presented too. This code can conduct tri-coupled thermo-mechanical-metallurgical simulations of forming processes. The numerical model has been used to carry out a 3D simulation of a forging process of a complex shape part. The model is able to take into account the effects of all the phenomena resulting from the coupling of thermal, mechanical and metallurgical events. As simulation results strongly depend on the accuracy of input data, physical simulation experiments on real-material samples are carried out to characterize material behavior during phase transformation.

Ducato, Antonino; Fratini, Livan; Micari, Fabrizio

2013-05-01

28

Forging; Heat Treating and Testing; Technically Oriented Industrial Materials and Process 1: 5898.05.  

ERIC Educational Resources Information Center

The course provides students with advanced and exploratory experience in the area of plastic deformation of metals and in the changing of the physical characteristics of metals by the controlled application and timed removal of heat. Course content includes goals, specific objectives, safety in forge work, forging tools and equipment, industrial…

Dade County Public Schools, Miami, FL.

29

Influence of minimum quantity lubrication parameters on tool wear and surface roughness in milling of forged steel  

NASA Astrophysics Data System (ADS)

The minimum quantity of lubrication (MQL) technique is becoming increasingly more popular due to the safety of environment. Moreover, MQL technique not only leads to economical benefits by way of saving lubricant costs but also presents better machinability. However, the effect of MQL parameters on machining is still not clear, which needs to be overcome. In this paper, the effect of different modes of lubrication, i.e., conventional way using flushing, dry cutting and using the minimum quantity lubrication (MQL) technique on the machinability in end milling of a forged steel (50CrMnMo), is investigated. The influence of MQL parameters on tool wear and surface roughness is also discussed. MQL parameters include nozzle direction in relation to feed direction, nozzle elevation angle, distance from the nozzle tip to the cutting zone, lubricant flow rate and air pressure. The investigation results show that MQL technique lowers the tool wear and surface roughness values compared with that of conventional flood cutting fluid supply and dry cutting conditions. Based on the investigations of chip morphology and color, MQL technique reduces the cutting temperature to some extent. The relative nozzle-feed position at 120°, the angle elevation of 60° and distance from nozzle tip to cutting zone at 20 mm provide the prolonged tool life and reduced surface roughness values. This fact is due to the oil mists can penetrate in the inner zones of the tool edges in a very efficient way. Improvement in tool life and surface finish could be achieved utilizing higher oil flow rate and higher compressed air pressure. Moreover, oil flow rate increased from 43.8 mL/h to 58.4 mL/h leads to a small decrease of flank wear, but it is not very significant. The results obtained in this paper can be used to determine optimal conditions for milling of forged steel under MQL conditions.

Yan, Lutao; Yuan, Songmei; Liu, Qiang

2012-05-01

30

Measurement system for hot heavy forgings and its calibration  

NASA Astrophysics Data System (ADS)

Dimensional measurement of hot heavy forgings is desirable to permit real-time process control, but usually is inconvenient because of the difficulty in working with very hot workpieces. This paper presents an approach based on Two-dimensional Laser Range Sensor (TLRS). Firstly, the measurement system can be obtained by assembling TLRS, an axis of rotation, and a servo motor, which rotates and scans forgings in different planes. Then, the coordinates of points of forging's surface can be obtained in coordinate system in scanning plane. Secondly, the origin of Measurement Coordinate System (MCS) at the centre of rotation of TLRS can be located. According to the transformation between Sensor Coordinate System (SCS) and MCS, coordinates of points in different SCS can be transferred into the fixed MCS. Next, the final points of forging's surface in MCS can be obtained. Hence models of hot heavy forgings can be reconstructed by using Triangulated Irregular Network and optimized by employing Delaunay rules. Finally, different parameters of forgings, such as lengths and diameters, can be measured. In order to calibrate the measurement system, a pyramid is proposed to compute the transformation matrix between SCS and MCS based on the projective geometry theory. The new method has been verified by experiments in both the laboratory and the forging workshop. The experimental results indicate that it is much more practical for the real time on-site measurement of hot heavy forgings. This research lays a desirable foundation for the further work.

Du, Yueyang; Du, Zhengchun

2011-05-01

31

Efficient process design for closure and healing of voids in open die forging of superhigh C-steel shaft  

NASA Astrophysics Data System (ADS)

In this study, simulation and experimental works are carried out to propose the efficient forging process design for manufacturing workroll made of 1.5wt%C high carbon steel. New forging process design is composed of incremental upsetting, diffusion boding and cogging process for efficient void closure and healing. Since the voids lie along the longitudinal direction of the ingot, the ingot is gradually deformed only in its radial direction during incremental upsetting until void closure takes place. After that, the closed voids are healed by diffusion bonding process in order to assign the strong bonding strength to the closed void and to prevent the re-opening of the closed voids during successive incremental upsetting and cogging process. Experimental works are also carried out to validate the proposed forging process design. In addition, the effect of temperature of diffusion bonding on bonding strength of the closed void is investigated. Finally, the analyses on microstructure at the diffusion-bonded interface and mechanical properties by tensile test are carried out as well. It was found out through simulation and experimental works that the quick void closure takes place by incremental upsetting and the closed void is strongly joined by diffusion bonding. It was confirmed that the process design proposed in this study can be applicable to manufacture the super high carbon workroll with microstructurally soundness.

Kang, Seong-Hoon; Lim, Hyung-Cheol; Lee, Howon; Lee, Young-Seon

2013-05-01

32

Processing and properties of superclean ASTM A508 Cl. 4 forgings  

SciTech Connect

Steels with improved resistance to temper embrittlement are now being produced using ``superclean`` steelmaking technology. This technology involves the use of scrap control, proper electric arc furnace and ladle refining furnace practices to produce steel with very low Mn, Si, P, S and other residual impurities such as Sn, As and Sb. This technology has been applied on a production basis to modified ASTM A508 Cl- 4 material intended for high temperature pressure vessel forgings. Processing and properties of this superclean material are reviewed. In addition, the cleanliness and mechanical properties are compared to conventionally melted A508 Cl. 4 material. The ``superclean`` A508 Cl. 4 mod. was found to meet all specification requirements. In addition, the superclean material was found to possess superior upper shelf CVN properties, a lower FATT{sub 50} and NDTT, along with superior microcleanliness compared to conventional material. Finally, the superclean material was found to be immune to temper embrittlement based on the short-term embrittlement treatments examined.

Hinkel, A.V.; Handerhan, K.J. [Ellwood City Forge, PA (United States); Manzo, G.J. [Ellwood Group Inc., PA (United States). Steel Division; Simkins, G.P. [Westinghouse Electric Corp., Pittsburgh, PA (United States)

1988-12-31

33

Detection of composite forged image  

Microsoft Academic Search

With the development of digital technology, original analog photograph has been increasingly replaced by digital image, and the forgery of digital image has become more and more easy and diversiform. For the most common blur operations of composite forged image, this paper presents a localization approach of forged region based on detection of image edge. First of all, we process

Zhen Zhang; Zhou Yu; BaiNa Su

2010-01-01

34

Effect of forging parameters on low cycle fatigue behaviour of Al/basalt short fiber metal matrix composites.  

PubMed

This paper deals with metal matrix composites (MMCs) of Al 7075 alloy containing different weight percentage (2.5, 5, 7.5, and 10) basalt short fiber reinforcement and unreinforced matrix alloy. The samples were produced by the permanent stir casting technique. The casting ingots were cut into blanks to be forged in single stage and double stage, using MN press and graphite-based lubricant. The microstructures and fatigue properties of the matrix alloy and MMC samples were investigated in the as cast state and in the single and double stage forging operations. The microstructure results showed that the forged sample had a uniform distribution of the basalt short fiber throughout the specimens. Evaluation of the fatigue properties showed that the forged samples had higher values than those of the as cast counterparts. After forging, the enhancement of the fatigue strength of the matrix alloy was so significant and high in the case of 2.5 and 5.0?wt. percentage basalt short fiber reinforced MMC, and there was no enhancement in 7.5 and 10?weight percentages short fiber reinforced MMCs. The fracture damage was mainly due to decohesion at the matrix-fiber interface. PMID:24298207

Karthigeyan, R; Ranganath, G

2013-01-01

35

Effect of Forging Parameters on Low Cycle Fatigue Behaviour of Al/Basalt Short Fiber Metal Matrix Composites  

PubMed Central

This paper deals with metal matrix composites (MMCs) of Al 7075 alloy containing different weight percentage (2.5, 5, 7.5, and 10) basalt short fiber reinforcement and unreinforced matrix alloy. The samples were produced by the permanent stir casting technique. The casting ingots were cut into blanks to be forged in single stage and double stage, using MN press and graphite-based lubricant. The microstructures and fatigue properties of the matrix alloy and MMC samples were investigated in the as cast state and in the single and double stage forging operations. The microstructure results showed that the forged sample had a uniform distribution of the basalt short fiber throughout the specimens. Evaluation of the fatigue properties showed that the forged samples had higher values than those of the as cast counterparts. After forging, the enhancement of the fatigue strength of the matrix alloy was so significant and high in the case of 2.5 and 5.0?wt. percentage basalt short fiber reinforced MMC, and there was no enhancement in 7.5 and 10?weight percentages short fiber reinforced MMCs. The fracture damage was mainly due to decohesion at the matrix-fiber interface. PMID:24298207

Karthigeyan, R.; Ranganath, G.

2013-01-01

36

Effect of gate shape and forging temperature on the mechanical properties in the injection forging process of semi-solid aluminum material  

Microsoft Academic Search

Semi-solid materials (SSM) were fabricated under two fabrication conditions by mechanical stirring. Re-heating conditions of SSM with the two fabrication methods (mechanical and electro-magnetic stirring) were studied with two holding times and three re-heating temperatures. SSM forging was conducted with three different die temperatures (Tdie=250, 300 and 350°C) and two gate types (straight gate and orifice gate). The mechanical properties

C. G Kang; J. S Choi

1998-01-01

37

Bioresorbable composite screws manufactured via forging process: pull-out, shear, flexural and degradation characteristics.  

PubMed

Bioresorbable screws have the potential to overcome some of the complications associated with metallic screws currently in use. Removal of metallic screws after bone has healed is a serious issue which can lead to refracture due to the presence of screw holes. Poly lactic acid (PLA), fully 40 mol% P(2)O(5) containing phosphate unidirectional (P40UD) and a mixture of UD and short chopped strand random fibre mats (P40 70%UD/30%RM) composite screws were prepared via forging composite bars. Water uptake and mass loss for the composite screws manufactured increased significantly to ?1.25% (P=0.0002) and ?1.1% (P<0.0001), respectively, after 42 days of immersion in PBS at 37 °C. The initial maximum flexural load for P40 UD/RM and P40 UD composite screws was ?60% (P=0.0047) and ?100% (P=0.0037) higher than for the PLA screws (?190 N), whilst the shear load was slightly higher in comparison to PLA (?2.2 kN). The initial pull-out strengths for the P40 UD/RM and PLA screws were similar whereas that for P40 UD screws was ?75% higher (P=0.022). Mechanical properties for the composite screws decreased initially after 3 days of immersion and this reduction was ascribed to the degradation of the fibre/matrix interface. After 3 days interval the mechanical properties (flexural, shear and pull-out) maintained their integrity for the duration of the study (at 42 days). This property retention was attributed to the chemical durability of the fibres used and stability of the matrix properties during the degradation process. It was also deemed necessary to enhance the fibre/matrix interface via use of a coupling agent in order to maintain the initial mechanical properties acquired for the required period of time. Lastly, it is also suggested that the degrading reinforcement fibres may have the potential to buffer any acidic products released from the PLA matrix. PMID:23262309

Felfel, R M; Ahmed, I; Parsons, A J; Rudd, C D

2013-02-01

38

Process Damping Parameters  

NASA Astrophysics Data System (ADS)

The phenomenon of process damping as a stabilising effect in milling has been encountered by machinists since milling and turning began. It is of great importance when milling aerospace alloys where maximum surface speed is limited by excessive tool wear and high speed stability lobes cannot be attained. Much of the established research into regenerative chatter and chatter avoidance has focussed on stability lobe theory with different analytical and time domain models developed to expand on the theory first developed by Trusty and Tobias. Process damping is a stabilising effect that occurs when the surface speed is low relative to the dominant natural frequency of the system and has been less successfully modelled and understood. Process damping is believed to be influenced by the interference of the relief face of the cutting tool with the waveform traced on the cut surface, with material properties and the relief geometry of the tool believed to be key factors governing performance. This study combines experimental trials with Finite Element (FE) simulation in an attempt to identify and understand the key factors influencing process damping performance in titanium milling. Rake angle, relief angle and chip thickness are the variables considered experimentally with the FE study looking at average radial and tangential forces and surface compressive stress. For the experimental study a technique is developed to identify the critical process damping wavelength as a means of measuring process damping performance. For the range of parameters studied, chip thickness is found to be the dominant factor with maximum stable parameters increased by a factor of 17 in the best case. Within the range studied, relief angle was found to have a lesser effect than expected whilst rake angle had an influence.

Turner, Sam

2011-12-01

39

New Trends in Forging Technologies  

NASA Astrophysics Data System (ADS)

Limited natural resources increase the demand on highly efficient machinery and transportation means. New energy-saving mobility concepts call for design optimisation through downsizing of components and choice of corrosion resistant materials possessing high strength to density ratios. Component downsizing can be performed either by constructive structural optimisation or by substituting heavy materials with lighter high-strength ones. In this context, forging plays an important role in manufacturing load-optimised structural components. At the Institute of Metal Forming and Metal-Forming Machines (IFUM) various innovative forging technologies have been developed. With regard to structural optimisation, different strategies for localised reinforcement of components were investigated. Locally induced strain hardening by means of cold forging under a superimposed hydrostatic pressure could be realised. In addition, controlled martensitic zones could be created through forming induced phase conversion in metastable austenitic steels. Other research focused on the replacement of heavy steel parts with high-strength nonferrous alloys or hybrid material compounds. Several forging processes of magnesium, aluminium and titanium alloys for different aeronautical and automotive applications were developed. The whole process chain from material characterisation via simulation-based process design to the production of the parts has been considered. The feasibility of forging complex shaped geometries using these alloys was confirmed. In spite of the difficulties encountered due to machine noise and high temperature, acoustic emission (AE) technique has been successfully applied for online monitoring of forging defects. New AE analysis algorithm has been developed, so that different signal patterns due to various events such as product/die cracking or die wear could be detected and classified. Further, the feasibility of the mentioned forging technologies was proven by means of the finite element analysis (FEA). For example, the integrity of forging dies with respect to crack initiation due to thermo-mechanical fatigue as well as the ductile damage of forgings was investigated with the help of cumulative damage models. In this paper some of the mentioned approaches are described.

Behrens, B.-A.; Hagen, T.; Knigge, J.; Elgaly, I.; Hadifi, T.; Bouguecha, A.

2011-05-01

40

On Extrusion Forging and Extrusion Rolling of Thin Metal Sheets  

E-print Network

Sheet metal surfaces with pin-fin features have potential fluid and thermal applications. Extrusion forging process and extrusion rolling process can be used to create such surface features on sheet metals. Extrusion forging process is a metal...

Feng, Zhujian

2013-01-10

41

High-energy rate forgings of wedges :  

SciTech Connect

The wedge geometry is a simple geometry for establishing a relatively constant gradient of strain in a forged part. The geometry is used to establish gradients in microstructure and strength as a function of strain, forging temperature, and quenching time after forging. This geometry has previously been used to benchmark predictions of strength and recrystallization using Sandias materials model for type 304L austenitic stainless steel. In this report, the processing conditions, in particular the times to forge and quench the forged parts, are summarized based on information recorded during forging on June 18, 2013 of the so-called wedge geometry from type 316L and 21Cr-6Ni-9Mn austenitic stainless steels.

Reynolds, Thomas Bither; Everhart, Wesley; Switzner, Nathan T; Balch, Dorian K.; San Marchi, Christopher W.

2014-05-01

42

The effect of processing upon the fracture behavior of cast and forged low alloy steel wellhead components  

E-print Network

vi viii INTRODUCTION Evaluating Material for Forged Components Comparing Castings and Forgings MATERIALS AND METHODS EXPERIMENTAL RESULTS 6 15 29 59 Results 1'rom Wrought Components Results from Cast Components Results from Subsequently... at several temperatures for material from the 4140 23 cm (9") diameter bar. Table 8 ? Values of K and tearing resistance (TR) 66 Jc at several temperatures for material from 4140 15 cm (6") diameter bar. vii Page Table 9 ? Values of KJ and tearing...

Desadier, Christopher Earl

1987-01-01

43

Phased Array Ultrasonic Inspection of Titanium Forgings  

SciTech Connect

Aerospace forging inspections typically use multiple, subsurface-focused sound beams in combination with digital C-scan image acquisition and display. Traditionally, forging inspections have been implemented using multiple single element, fixed focused transducers. Recent advances in phased array technology have made it possible to perform an equivalent inspection using a single phased array transducer. General Electric has developed a system to perform titanium forging inspection based on medical phased array technology and advanced image processing techniques. The components of that system and system performance for titanium inspection will be discussed.

Howard, P.; Klaassen, R.; Kurkcu, N. [GE Aviation, 1 Neumann Way, Mail Drop Q8, Cincinnati, OH 45208 (United States); Barshinger, J.; Chalek, C.; Nieters, E.; Sun, Zongqi [GE Global Research, 1 Research Circle, Niskayuna, NY 12309 (United States); Fromont, F. de [GE Inspection Technologies, 50 Industrial Park Road, Lewistown, PA 17044 (United States)

2007-03-21

44

Superplastic forging nitride ceramics  

DOEpatents

A process is disclosed for preparing silicon nitride ceramic parts which are relatively flaw free and which need little or no machining, said process comprising the steps of: (a) preparing a starting powder by wet or dry mixing ingredients comprising by weight from about 70% to about 99% silicon nitride, from about 1% to about 30% of liquid phase forming additive and from 1% to about 7% free silicon; (b) cold pressing to obtain a preform of green density ranging from about 30% to about 75% of theoretical density; (c) sintering at atmospheric pressure in a nitrogen atmosphere at a temperature ranging from about 1,400 C to about 2,200 C to obtain a density which ranges from about 50% to about 100% of theoretical density and which is higher than said preform green density, and (d) press forging workpiece resulting from step (c) by isothermally uniaxially pressing said workpiece in an open die without initial contact between said workpiece and die wall perpendicular to the direction of pressing and so that pressed workpiece does not contact die wall perpendicular to the direction of pressing, to substantially final shape in a nitrogen atmosphere utilizing a temperature within the range of from about 1,400 C to essentially 1,750 C and strain rate within the range of about 10[sup [minus]7] to about 10[sup [minus]1] seconds[sup [minus]1], the temperature and strain rate being such that surface cracks do not occur, said pressing being carried out to obtain a shear deformation greater than 30% whereby superplastic forging is effected.

Panda, P.C.; Seydel, E.R.; Raj, R.

1988-03-22

45

Enhancement of Aluminum Alloy Forgings through Rapid Billet Heating  

SciTech Connect

Forging is a manufacturing process in which metal is pressed, pounded or squeezed under great pressure and, often, under high strain rates into high-strength parts known as forgings. The process is typically performed hot by preheating the metal to a desired temperature before it is worked. The forging process can create parts that are stronger than those manufactured by any other metal working process. Forgings are almost always used where reliability and human safety are critical. Forgings are normally component parts contained inside assembled items such airplanes, automobiles, tractors, ships, oil drilling equipment, engines missiles, and all kinds of capital equipment Forgings are stronger than castings and surpass them in predictable strength properties, producing superior strength that is assured, part to part.

Kervick, R.; Blue, C. A.; Kadolkar, P. B.; Ando, T.; Lu, H.; Nakazawa, K.; Mayer, H.; Mochnal, G.

2006-06-01

46

Mechanical Testing Development for Reservoir Forgings  

SciTech Connect

The goal of this project was to determine the machining techniques and testing capabilities required for mechanical property evaluation of commercially procured reservoir forgings. Due to the small size of these specific forgings, specialized methods are required to adequately machine and test these sub-miniature samples in accordance with the requirements of ASTM-E8 and ASTM-E9. At the time of project initiation, no capability existed at Federal Manufacturing & Technologies (FM&T) to verify the physical properties of these reservoirs as required on the drawing specifications. The project determined the sample definitions, machining processes, and testing procedures to verify the physical properties of the reservoir forgings; specifically, tensile strength, yield strength, reduction of area, and elongation. In addition, a compression test method was also developed to minimize sample preparation time and provide a more easily machined test sample while maintaining the physical validation of the forging.

Wenski, E.G.

2000-05-22

47

A PACVD duplex coating for hot-forging applications  

Microsoft Academic Search

The tribological loading of forging tools is caused by the relative motion between the plastically deformed work piece and the die. In comparison to many other forming processes, hot forging has an especially disadvantageous tribological system, combining thermal, mechanical and chemical loadings. The advantages of hard coatings, which are well known for cutting tools, are to a much lesser extent

V. Leskovšek; B. Podgornik; M. Jenko

2009-01-01

48

Partners: Forging Strong Relationships.  

ERIC Educational Resources Information Center

This newsletter issue asserts that sound, effective relationships in which diverse groups of people and organizations work together toward a common goal are the basis of the collaborative efforts in education that can accomplish change. The first article, "Partners: Forging Strong Relationships" (Sarah E. Torian), briefly describes the efforts of…

Spears, Ellen, Ed.

1999-01-01

49

Near-Net Forging Technology Demonstration Program  

NASA Technical Reports Server (NTRS)

Significant advantages in specific mechanical properties, when compared to conventional aluminum (Al) alloys, make aluminum-lithium (Al-Li) alloys attractive candidate materials for use in cryogenic propellant tanks and dry bay structures. However, the cost of Al-Li alloys is typically five times that of 2219 aluminum. If conventional fabrication processes are employed to fabricate launch vehicle structure, the material costs will restrict their utilization. In order to fully exploit the potential cost and performance benefits of Al-Li alloys, it is necessary that near-net manufacturing methods be developed to off-set or reduce raw material costs. Near-net forging is an advanced manufacturing method that uses elevated temperature metal movement (forging) to fabricate a single piece, near-net shape, structure. This process is termed 'near-net' because only a minimal amount of post-forge machining is required. The near-net forging process was developed to reduce the material scrap rate (buy-to-fly ratio) and fabrication costs associated with conventional manufacturing methods. The goal for the near-net forging process, when mature, is to achieve an overall cost reduction of approximately 50 percent compared with conventional manufacturing options for producing structures fabricated from Al-Li alloys. This NASA Marshall Space Flight Center (MSFC) sponsored program has been a part of a unique government / industry partnership, coordinated to develop and demonstrate near-net forging technology. The objective of this program was to demonstrate scale-up of the near-net forging process. This objective was successfully achieved by fabricating four integrally stiffened, 170- inch diameter by 20-inch tall, Al-Li alloy 2195, Y-ring adapters. Initially, two 2195 Al-Li ingots were converted and back extruded to produce four cylindrical blockers. Conventional ring rolling of the blockers was performed to produce ring preforms, which were then contour ring rolled to produce 'contour preforms'. All of the contour preforms on this first-of-a-kind effort were imperfect, and the ingot used to fabricate two of the preforms was of an earlier vintage. As lessons were learned throughout the program, the tooling and procedures evolved, and hence the preform quality. Two of the best contour preforms were near- net forged to produce a process pathfinder Y-ring adapter and a 'mechanical properties pathfinder' Y-ring adapter. At this point, Lockheed Martin Astronautics elected to procure additional 2195 aluminum-lithium ingot of the latest vintage, produce two additional preforms, and substitute them for older vintage material non-perfectly filled preforms already produced on this contract. The existing preforms could have been used to fulfill the requirements of the contract.

Hall, I. Keith

1996-01-01

50

Friction and wear in hot forging of steels  

SciTech Connect

In the field of hot forging of steels, the mastering of wear phenomena enables to save cost production, especially concerning tools. Surfaces of tools are protected thanks to graphite. The existing lubrication processes are not very well known: amount and quality of lubricant, lubrication techniques have to be strongly optimized to delay wear phenomena occurrence. This optimization is linked with hot forging processes, the lubricant layers must be tested according to representative friction conditions. This paper presents the first part of a global study focused on wear phenomena encountered in hot forging of steels. The goal is the identification of reliable parameters, in order to bring knowledge and models of wear. A prototype testing stand developed in the authors' laboratory is involved in this experimental analysis. This test is called Warm and Hot Upsetting Sliding Test (WHUST). The stand is composed of a heating induction system and a servo-hydraulic system. Workpieces taken from production can be heated until 1200 deg. C. A nitrided contactor representing the tool is heated at 200 deg. C. The contactor is then coated with graphite and rubs against the workpiece, leaving a residual track on it. Friction coefficient and surface parameters on the contactor and the workpiece are the most representative test results. The surface parameters are mainly the sliding length before defects occurrence, and the amplitude of surface profile of the contactor. The developed methodology will be first presented followed by the different parts of the experimental prototype. The results of experiment show clearly different levels of performance according to different lubricants.

Daouben, E. [LAMIH UMR CNRS 8530 - Universite de Valenciennes, Le Mont Houy - 59313 Valenciennes Cedex 9 (France); CONDAT Lubrifiants- Avenue Frederic Mistral, 38670 Chasses sur Rhones (France); Dubar, L.; Dubar, M.; Deltombe, R.; Dubois, A. [LAMIH UMR CNRS 8530 - Universite de Valenciennes, Le Mont Houy - 59313 Valenciennes Cedex 9 (France); Truong-Dinh, N. [CONDAT Lubrifiants- Avenue Frederic Mistral, 38670 Chasses sur Rhones (France); Lazzarotto, L. [CETIM - Etablissement de Saint Etienne 7, rue de la Presse - BP 802, 42952 Saint Etienne Cedex 9 (France)

2007-04-07

51

Superplastic forging nitride ceramics  

DOEpatents

The invention relates to producing relatively flaw free silicon nitride ceramic shapes requiring little or no machining by superplastic forging This invention herein was made in part under Department of Energy Grant DE-AC01-84ER80167, creating certain rights in the United States Government. The invention was also made in part under New York State Science and Technology Grant SB1R 1985-10.

Panda, Prakash C. (Ithaca, NY); Seydel, Edgar R. (Ithaca, NY); Raj, Rishi (Ithaca, NY)

1988-03-22

52

A material based approach to creating wear resistant surfaces for hot forging  

NASA Astrophysics Data System (ADS)

Tools and dies used in metal forming are characterized by extremely high temperatures at the interface, high local pressures and large metal to metal sliding. These harsh conditions result in accelerated wear of tooling. Lubrication of tools, done to improve metal flow drastically quenches the surface layers of the tools and compounds the tool failure problem. This phenomenon becomes a serious issue when parts forged at complex and are expected to meet tight tolerances. Unpredictable and hence uncontrolled wear and degradation of tooling result in poor part quality and premature tool failure that result in high scrap, shop downtime, poor efficiency and high cost. The objective of this dissertation is to develop a computer-based methodology for analyzing the requirements hot forging tooling to resist wear and plastic deformation and wear and predicting life cycle of forge tooling. Development of such is a system is complicated by the fact that wear and degradation of tooling is influenced by not only the die material used but also numerous process controls like lubricant, dilution ratio, forging temperature, equipment used, tool geometries among others. Phenomenological models available u1 the literature give us a good thumb rule to selecting materials but do not provide a way to evaluate pits performance in field. Once a material is chosen, there are no proven approaches to create surfaces out of these materials. Coating approaches like PVD and CVD cannot generate thick coatings necessary to withstand the conditions under hot forging. Welding cannot generate complex surfaces without several secondary operations like heat treating and machining. If careful procedures are not followed, welds crack and seldom survive forging loads. There is a strong need for an approach to selectively, reliably and precisely deposit material of choice reliably on an existing surface which exhibit not only good tribological properties but also good adhesion to the substrate. Dissertation outlines development of a new cyclic contact test design to recreate intermittent tempering seen in hot forging. This test has been used to validate the use of tempering parameters in modeling of in-service softening of tool steel surfaces. The dissertation also outlines an industrial case study, conducted at a forging company, to validate the wear model. This dissertation also outlines efforts at Ohio State University, to deposit Nickel Aluminide on AISI H13 substrate, using Laser Engineered Net Shaping (LENS). Dissertation reports results from an array of experiments conducted using LENS 750 machine, at various power levels, table speeds and hatch spacing. Results pertaining to bond quality, surface finish, compositional gradients and hardness are provided. Also, a thermal-based finite element numerical model that was used to simulate the LENS process is presented, along with some demonstrated results.

Babu, Sailesh

53

Computer-Aided Design of Manufacturing Chain Based on Closed Die Forging for Hardly Deformable Cu-Based Alloys  

NASA Astrophysics Data System (ADS)

Two copper-based alloys were considered, Cu-1 pct Cr and Cu-0.7 pct Cr-1 pct Si-2 pct Ni. The thermal, electrical, and mechanical properties of these alloys are given in the paper and compared to pure copper and steel. The role of aging and precipitation kinetics in hardening of the alloys is discussed based upon the developed model. Results of plastometric tests performed at various temperatures and various strain rates are presented. The effect of the initial microstructure on the flow stress was investigated. Rheologic models for the alloys were developed. A finite element (FE) model based on the Norton-Hoff visco-plastic flow rule was applied to the simulation of forging of the alloys. Analysis of the die wear for various processes of hot and cold forging is presented as well. A microstructure evolution model was implemented into the FE code, and the microstructure and mechanical properties of final products were predicted. Various variants of the manufacturing cycles were considered. These include different preheating schedules, hot forging, cold forging, and aging. All variants were simulated using the FE method and loads, die filling, tool wear, and mechanical properties of products were predicted. Three variants giving the best combination of forging parameters were selected and industrial trials were performed. The best manufacturing technology for the copper-based alloys is proposed.

Pietrzyk, Maciej; Kuziak, Roman; Pidvysots'kyy, Valeriy; Nowak, Jaros?aw; W?glarczyk, Stanis?aw; Drozdowski, Krzysztof

2013-07-01

54

Advanced rotor forgings for high-temperature steam turbines. Volume 1. Ingot and forging production. Final report  

Microsoft Academic Search

Three advanced steel-melting processes - low-sulfur vacuum silicon deoxidation, electroslag remelting, and vacuum carbon deoxidation (VCD) - were applied to produce three CrMoV (ASTM A470, Class 8) steel forgings for steam turbine application. Ingots weighing about 100 t each were produced using these three processes, and rotors were forged with final weights of about 30 t each. Compared to the

V. P. Swaminathan; J. E. Steiner; A. Mitchell

1986-01-01

55

Selection of informative parameters of vibroacoustic processes  

NASA Technical Reports Server (NTRS)

The problem of selecting informative parameters of vibro-acoustic processes and the construction of apparatus for their determination are discussed. It is assumed that the processes being investigated are structurally uniform and either purely random or contain not very many determinative components.

Koshek, L. N.

1973-01-01

56

Surveillance of industrial processes with correlated parameters  

DOEpatents

A system and method for surveillance of an industrial process. The system and method includes a plurality of sensors monitoring industrial process parameters, devices to convert the sensed data to computer compatible information and a computer which executes computer software directed to analyzing the sensor data to discern statistically reliable alarm conditions. The computer software is executed to remove serial correlation information and then calculate Mahalanobis distribution data to carry out a probability ratio test to determine alarm conditions.

White, Andrew M. (Skokie, IL); Gross, Kenny C. (Bolingbrook, IL); Kubic, William L. (Sante Fe, NM); Wigeland, Roald A. (Olympia Fields, IL)

1996-01-01

57

Surveillance of industrial processes with correlated parameters  

DOEpatents

A system and method for surveillance of an industrial process are disclosed. The system and method includes a plurality of sensors monitoring industrial process parameters, devices to convert the sensed data to computer compatible information and a computer which executes computer software directed to analyzing the sensor data to discern statistically reliable alarm conditions. The computer software is executed to remove serial correlation information and then calculate Mahalanobis distribution data to carry out a probability ratio test to determine alarm conditions. 10 figs.

White, A.M.; Gross, K.C.; Kubic, W.L.; Wigeland, R.A.

1996-12-17

58

Hot shape forging of gas turbine disk using microstructure prediction and finite element analysis  

Microsoft Academic Search

The Waspaloy, a Ni-based superalloy, has been widely used for forging material of gas turbine disk since it requires the high\\u000a tensile strength at high temperature and good resistance to low cycle fatigue. The purpose of this study is to develop a forging\\u000a process of turbine disk that satisfies the hot deformation characteristics of Waspaloy. Generally, the hot forging of

Do-Jin Cha; Dong-Kwon Kim; Jong-Rae Cho; Won-Byong Bae

2011-01-01

59

Simulation and analysis of rotary forging a ring workpiece using finite element method  

Microsoft Academic Search

The methods of dealing with some key problems in analyzing a rotary forging process with a finite element method are given. The presented mechanical model of the finite element analysis is in accordance with the actual conditions of the rotary forging process. A three-dimensional rigid–plastic finite element analysis code is developed in FORTRAN language and used to analyze the rotary

Wang Guangchun; Zhao Guoqun

2002-01-01

60

Prediction of Microstructure in High-Strength Ductile Forging Parts  

SciTech Connect

Governmental, environmental and economic demands call for lighter, stiffer and at the same time cheaper products in the vehicle industry. Especially safety relevant parts have to be stiff and at the same time ductile. The strategy of this project was to improve the mechanical properties of forging steel alloys by employing a high-strength and ductile bainitic microstructure in the parts while maintaining cost effective process chains to reach these goals for high stressed forged parts. Therefore, a new steel alloy combined with an optimized process chain has been developed. To optimize the process chain with a minimum of expensive experiments, a numerical approach was developed to predict the microstructure of the steel alloy after the process chain based on FEM simulations of the forging and cooling combined with deformation-time-temperature-transformation-diagrams.

Urban, M.; Back, A.; Hirt, G. [Institute of Metal Forming (IBF), RWTH Aachen University, Aachen (Germany); Keul, C.; Bleck, W. [Institute of Ferrous Metallurgy (IEHK), RWTH Aachen University, Aachen (Germany)

2010-06-15

61

Effects of process parameters on hydrothermal carbonization  

NASA Astrophysics Data System (ADS)

In recent years there has been increased research activity in renewable energy, especially upgrading widely available lignicellulosic biomass, in a bid to counter the increasing environmental concerns related with the use of fossil fuels. Hydrothermal carbonization (HTC), also known as wet torrefaction or hot water pretreatment, is a process for pretreatment of diverse lignocellulosic biomass feedstocks, where biomass is treated under subcritical water conditions in short contact time to produce high-value products. The products of this process are: a solid mass characterized as biochar/biocoal/biocarbon, which is homogeneous, energy dense, and hydrophobic; a liquid stream composed of five and six carbon sugars, various organic acids, and 5-HMF; and a gaseous stream, mainly CO2. A number of process parameters are considered important for the extensive application of the HTC process. Primarily, reaction temperature determines the characteristics of the products. In the solid product, the oxygen carbon ratio decreases with increasing reaction temperature and as a result, HTC biochar has the similar characteristics to low rank coal. However, liquid and gaseous stream compositions are largely correlated with the residence time. Biomass particle size can also limit the reaction kinetics due to the mass transfer effect. Recycling of process water can help to minimize the utility consumption and reduce the waste treatment cost as a result of less environmental impact. Loblolly pine was treated in hot compressed water at 200 °C, 230 °C, and 260 °C with 5:1 water:biomass mass ratio to investigate the effects of process parameters on HTC. The solid product were characterized by their mass yields, higher heating values (HHV), and equilibrium moisture content (EMC), while the liquid were characterized by their total organic carbon content and pH value.

Uddin, Md. Helal

62

Heat Recovery in the Forge Industry  

E-print Network

Department of Energy figures reveal that in 1979 the forging and stamping operations were the primary consumers of energy (27%) within the 'Fabricated Metals Products Industry' (SIC 34). Industrial furnaces utilized by the forging industry often...

Shingledecker, R. B.

1982-01-01

63

Transatlantic Perspectives Forging Legitimizing Coalitions  

E-print Network

Transatlantic Perspectives Forging Legitimizing Coalitions: Comparing EU/U.S. Financial Consumer Policy | Tags: Economic & Financial Policy, History What is the role of non-state actors--corporate and civic--in influencing and redirecting regulatory reforms? How do critical junctures like financial

Boyer, Edmond

64

Nonstationary magnetotelluric data processing with instantaneous parameter  

NASA Astrophysics Data System (ADS)

Nonstationarity in electromagnetic data affects the computation of Fourier spectra and therefore the traditional estimation of the magnetotelluric (MT) transfer functions (TF). We provide a TF estimation scheme based on an emerging nonlinear, nonstationary time series analysis tool, called empirical mode decomposition (EMD) and show that this technique can handle nonstationary effects with which traditional methods encounter difficulties. In contrast to previous works that employ EMD for MT data processing, we argue the advantages of a multivariate decomposition, highlight the possibility to use instantaneous parameters, and define the homogenization of frequency discrepancies between data channels. Our scheme uses the robust statistical estimation of transfer functions based on robust principal component analysis and a robust iteratively reweighted least squares regression with a Huber weight function. The scheme can be applied with and without aid of any number of available remote reference stations. Uncertainties are estimated by iterating the complete robust regression, including the robust weight computation, with a bootstrap routine. We apply our scheme to synthetic and real data (Southern Africa) with and without nonstationary character and compare different processing techniques to the one presented here. As a conclusion, nonstationary noise can heavily affect Fourier-based MT data processing but the presented nonstationary approach is nonetheless able to extract the impedances.

Neukirch, M.; Garcia, X.

2014-03-01

65

Development of high purity large forgings for nuclear power plants  

NASA Astrophysics Data System (ADS)

The recent increase in the size of energy plants has been supported by the development of manufacturing technology for high purity large forgings for the key components of the plant. To assure the reliability and performance of the large forgings, refining technology to make high purity steels, casting technology for gigantic ingots, forging technology to homogenize the material and consolidate porosity are essential, together with the required heat treatment and machining technologies. To meet these needs, the double degassing method to reduce impurities, multi-pouring methods to cast the gigantic ingots, vacuum carbon deoxidization, the warm forging process and related technologies have been developed and further improved. Furthermore, melting facilities including vacuum induction melting and electro slag re-melting furnaces have been installed. By using these technologies and equipment, large forgings have been manufactured and shipped to customers. These technologies have also been applied to the manufacture of austenitic steel vessel components of the fast breeder reactors and components for fusion experiments.

Tanaka, Yasuhiko; Sato, Ikuo

2011-10-01

66

HYDROGEN-ASSISTED FRACTURE IN FORGED TYPE 304L AUSTENITIC STAINLESS STEEL  

SciTech Connect

Austenitic stainless steels generally have good resistance to hydrogen-assisted fracture; however, structural designs for high-pressure gaseous hydrogen are constrained by the low strength of this class of material. Forging is used to increase the low strength of austenitic stainless steels, thus improving the efficiency of structural designs. Hydrogen-assisted racture, however, depends on microstructural details associated with manufacturing. In this study, hydrogen-assisted fracture of forged type 304L austenitic stainless steel is investigated. Microstructural variation in multi-step forged 304L was achieved by forging at different rates and temperatures, and by process annealing. High internal hydrogen content in forged type 304L austenitic stainless steel is achieved by thermal precharging in gaseous hydrogen and results in as much as 50% reduction of tensile ductility.

Switzner, Nathan; Neidt, Ted; Hollenbeck, John; Knutson, J.; Everhart, Wes; Hanlin, R. [University of Missouri-Kansas City] [University of Missouri-Kansas City; Bergen, R. [Precision Metal Products] [Precision Metal Products; Balch, D. K. [Sandia Natl Laboratory] [Sandia Natl Laboratory

2012-09-06

67

A Study on the Microstructure Change with Modification and Cast-forging in Hypereutectic Al-Si Alloys  

Microsoft Academic Search

For application of cast-forging process with Al-Si hypereutectic alloys, casting experiments are carried out by adding P and Sr to Al-Si hypereutectic alloys for eutectic and primary Si refinement treatment. We experimented on the mechanical properties according to microstructural changes, forging ability test and also investigated the mechanical properties after forging. The finest microstructure could be observed respectively when 0.075

E. S. Kim; K. M. Lim; Y. H. Kim; K. H. Lee

2006-01-01

68

A new approach to model the fatigue anisotropy due to non-metallic inclusions in forged steels  

E-print Network

fatigue crack initiation mechanisms. The anisotropic character of the fatigue resistance of forged: anisotropic, forging, manganese sulphide inclusions, high cycle fatigue, linear elastic fracture mechanics stress amplitude , : material parameter for the Dang Van criterion 1 T : fatigue strength at 2x106 cycles

Paris-Sud XI, Université de

69

27 CFR 447.22 - Forgings, castings, and machined bodies.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Forgings, castings, and machined bodies. 447.22 ...Import List § 447.22 Forgings, castings, and machined bodies. Articles...partially completed state (such as forgings, castings, extrusions, and machined...

2013-04-01

70

22 CFR 121.10 - Forgings, castings and machined bodies.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false Forgings, castings and machined bodies. 121.10 Section...of Articles § 121.10 Forgings, castings and machined bodies. Articles on...partially completed state (such as forgings, castings, extrusions and machined...

2011-04-01

71

22 CFR 121.10 - Forgings, castings and machined bodies.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Forgings, castings and machined bodies. 121.10 Section...of Articles § 121.10 Forgings, castings and machined bodies. Articles on...partially completed state (such as forgings, castings, extrusions and machined...

2010-04-01

72

27 CFR 447.22 - Forgings, castings, and machined bodies.  

Code of Federal Regulations, 2012 CFR

... 2010-04-01 true Forgings, castings, and machined bodies. 447.22 ...Import List § 447.22 Forgings, castings, and machined bodies. Articles...partially completed state (such as forgings, castings, extrusions, and machined...

2012-04-01

73

22 CFR 121.10 - Forgings, castings and machined bodies.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Forgings, castings and machined bodies. 121.10 Section...of Articles § 121.10 Forgings, castings and machined bodies. Articles on...partially completed state (such as forgings, castings, extrusions and machined...

2013-04-01

74

27 CFR 447.22 - Forgings, castings, and machined bodies.  

Code of Federal Regulations, 2014 CFR

... 2014-04-01 false Forgings, castings, and machined bodies. 447.22 ...Import List § 447.22 Forgings, castings, and machined bodies. Articles...partially completed state (such as forgings, castings, extrusions, and machined...

2014-04-01

75

22 CFR 121.10 - Forgings, castings and machined bodies.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 false Forgings, castings and machined bodies. 121.10 Section...of Articles § 121.10 Forgings, castings and machined bodies. Articles on...partially completed state (such as forgings, castings, extrusions and machined...

2012-04-01

76

27 CFR 447.22 - Forgings, castings, and machined bodies.  

Code of Federal Regulations, 2011 CFR

... 2010-04-01 true Forgings, castings, and machined bodies. 447.22 ...Import List § 447.22 Forgings, castings, and machined bodies. Articles...partially completed state (such as forgings, castings, extrusions, and machined...

2011-04-01

77

Effect of processing parameters on autoclaved PMR polyimide composites  

NASA Technical Reports Server (NTRS)

A study was conducted to determine the effect of processing parameters on the processability and properties of autoclaved fiber reinforced PMR polyimide composites. Composites were fabricated from commercially available graphite fabric and glass fabric PMR polyimide prepreg materials. Process parameters investigated included degree of resin advancement, heating rate, and cure pressure. Composites were inspected for porosity by ultrasonic C scan and photomicrographic examination. Processing characteristics for each set of process parameters and the effect of process parameters on composite mechanical properties at room temperature and 600 F are described.

Vannucci, R. D.

1977-01-01

78

Evaluation of Control Parameters for the Activated Sludge Process  

ERIC Educational Resources Information Center

An evaluation of the use of the parameters currently being used to design and operate the activated sludge process is presented. The advantages and disadvantages for the use of each parameter are discussed. (MR)

Stall, T. Ray; Sherrard, Josephy H.

1978-01-01

79

Reactor pressure vessel with forged nozzles  

DOEpatents

Inlet nozzles for a gravity-driven cooling system (GDCS) are forged with a cylindrical reactor pressure vessel (RPV) section to which a support skirt for the RPV is attached. The forging provides enhanced RPV integrity around the nozzle and substantial reduction of in-service inspection costs by eliminating GDCS nozzle-to-RPV welds.

Desai, Dilip R. (Fremont, CA)

1993-01-01

80

Deformation Mechanisms in Tube Billets from Zr-1%Nb Alloy under Radial Forging  

NASA Astrophysics Data System (ADS)

Features of the deformation process by cold radial forging of tube billets from Zr-1%Nb alloy were reconstructed on the basis of X-ray data concerning their structure and texture. The cold radial forging intensifies grain fragmentation in the bulk of billet and increases significantly the latent hardening of potentially active slip systems, so that operation only of the single slip system becomes possible. As a result, in radially-forged billets unusual deformation and recrystallization textures arise. These textures differ from usual textures of ?-Zr by the mutual inversion of crystallographic axes, aligned along the axis of tube.

Perlovich, Yuriy; Isaenkova, Margarita; Fesenko, Vladimir; Krymskaya, Olga; Zavodchikov, Alexander

2011-05-01

81

Deformation Mechanisms in Tube Billets from Zr-1%Nb Alloy under Radial Forging  

SciTech Connect

Features of the deformation process by cold radial forging of tube billets from Zr-1%Nb alloy were reconstructed on the basis of X-ray data concerning their structure and texture. The cold radial forging intensifies grain fragmentation in the bulk of billet and increases significantly the latent hardening of potentially active slip systems, so that operation only of the single slip system becomes possible. As a result, in radially-forged billets unusual deformation and recrystallization textures arise. These textures differ from usual textures of {alpha}-Zr by the mutual inversion of crystallographic axes, aligned along the axis of tube.

Perlovich, Yuriy; Isaenkova, Margarita; Fesenko, Vladimir; Krymskaya, Olga [National Research Nuclear University 'Moscow Engineering Physics Institute', Kashirskoe shosse, 31, Moscow, 115409 (Russian Federation); Zavodchikov, Alexander [Perm Research Technological Institute, Hasan Heroes street, 41, Perm, 614990 (Russian Federation)

2011-05-04

82

Processing parameters affecting sorghum noodle qualities  

E-print Network

Processing variables of 100% sorghum noodles were investigated to determine effects on noodle quality. A dough was created by microwave heating a flour with 1 % salt (1 00 g): water (90 ml) mixture to 950C with a microwave. The dough was put through...

Kunetz, Christine Frances

1997-01-01

83

Department of Industrial Engineering Spring 2012 Lyophilization Process Parameter Study  

E-print Network

PENNSTATE Department of Industrial Engineering Spring 2012 Lyophilization Process Parameter Study Overview Life Technologies is a global leader in producing biotechnology products that improve the quality

Demirel, Melik C.

84

Temporal parameter sensitivity guided verification of process dynamics  

NASA Astrophysics Data System (ADS)

To ensure reliable results of a hydrological model, it is essential that the model reproduces the hydrological processes adequately. Information about process dynamics is provided by looking at the temporal sensitivities of the corresponding model parameters. For this, the temporal dynamics of parameter sensitivity are used to describe the dominance of parameters for each time step. The parameter dominance is then related to the corresponding hydrological process, since the temporal parameter sensitivity represents the modelled hydrological process. For a reliable model application it has to be verified that the modelled hydrological processes match the expectations of real-world hydrological processes. We present a framework, which distinguishes between a verification of single model components and of the overall model behaviour. We analyse the temporal dynamics of parameter sensitivity of a modified groundwater component of a hydrological model. The results of the single analysis for the modified component show that the behaviour of the parameters of the modified groundwater component is consistent with the idea of the structural modifications. Additionally, the appropriate simulation of all relevant hydrological processes is verified as the temporal dynamics of parameter sensitivity represent these processes according to the expectations. Thus, we conclude that temporal dynamics of parameter sensitivity are helpful for verifying modifications of hydrological models.

Pfannerstill, M.; Guse, B.; Reusser, D.; Fohrer, N.

2015-02-01

85

Collective mass parameters in the nuclear fission process  

Microsoft Academic Search

The theory of nuclear fission process is considered. The effective mass parameters are calculated as a function of the following collective coordinates: the separation between the centres of harmonic oscillators, the mass asymmetry parameter and the necking parameter. Numerical calculations are carried out for the fission of236U and238U nuclei. Symmetric and asymmetric cases are considered. From the present calculation we

A. Osman; A. M. Abdel-Latif

1988-01-01

86

Strength computation of forged parts taking into account strain hardening and damage  

NASA Astrophysics Data System (ADS)

Modern non-linear simulation software, such as FORGE 3 (registered trade mark of TRANSVALOR), are able to compute the residual stresses, the strain hardening and the damage during the forging process. A thermally dependent elasto-visco-plastic law is used to simulate the behavior of the material of the hot forged piece. A modified Lemaitre law coupled with elasticiy, plasticity and thermic is used to simulate the damage. After the simulation of the different steps of the forging process, the part is cooled and then virtually machined, in order to obtain the finished part. An elastic computation is then performed to equilibrate the residual stresses, so that we obtain the true geometry of the finished part after machining. The response of the part to the loadings it will sustain during it's life is then computed, taking into account the residual stresses, the strain hardening and the damage that occur during forging. This process is illustrated by the forging, virtual machining and stress analysis of an aluminium wheel hub.

Cristescu, Michel L.

2004-06-01

87

Improvement of hot forging manufacturing with PVD and DUPLEX coatings  

Microsoft Academic Search

The application of a DUPLEX treatment, which included low pressure pulsed plasma nitriding of AISI H11 tool steel dies and PVD BALINIT® FUTURA-TiN\\/TiAlN multilayered coating, was studied as a possible technology to improve the process of hot forging of steel components. The quality of the DUPLEX treatment was determined by laboratory analyses of coated test plates, which were treated together

Boris Navinšek; Peter Panjan; Frank Gorenjak

2001-01-01

88

29 CFR 1910.218 - Forging machines.  

Code of Federal Regulations, 2010 CFR

...forge shop or die shop. (i) Thermostatic control of heating elements shall be provided to maintain proper melting temperature...manner that they will not fly off or fall in event of failure. (3) Hammers and presses. (i) All...

2010-07-01

89

29 CFR 1910.218 - Forging machines.  

Code of Federal Regulations, 2011 CFR

...forge shop or die shop. (i) Thermostatic control of heating elements shall be provided to maintain proper melting temperature...manner that they will not fly off or fall in event of failure. (3) Hammers and presses. (i) All...

2011-07-01

90

29 CFR 1910.218 - Forging machines.  

Code of Federal Regulations, 2013 CFR

...forge shop or die shop. (i) Thermostatic control of heating elements shall be provided to maintain proper melting temperature...manner that they will not fly off or fall in event of failure. (3) Hammers and presses. (i) All...

2013-07-01

91

29 CFR 1910.218 - Forging machines.  

Code of Federal Regulations, 2014 CFR

...forge shop or die shop. (i) Thermostatic control of heating elements shall be provided to maintain proper melting temperature...manner that they will not fly off or fall in event of failure. (3) Hammers and presses. (i) All...

2014-07-01

92

29 CFR 1910.218 - Forging machines.  

Code of Federal Regulations, 2012 CFR

...forge shop or die shop. (i) Thermostatic control of heating elements shall be provided to maintain proper melting temperature...manner that they will not fly off or fall in event of failure. (3) Hammers and presses. (i) All...

2012-07-01

93

T3PS: Tool for Parallel Processing in Parameter Scans  

E-print Network

T3PS is a program that can be used to quickly design and perform parameter scans while easily taking advantage of the multi-core architecture of current processors. It takes an easy to read and write parameter scan definition file format as input. Based on the parameter ranges and other options contained therein, it distributes the calculation of the parameter space over multiple processes and possibly computers. The derived data is saved in a plain text file format readable by most plotting software. The supported scanning strategies include: grid scan, random scan, Markov Chain Monte Carlo, numerical optimization. Several example parameter scans are shown and compared with results in the literature.

Maurer, Vinzenz

2015-01-01

94

Managing Credit Lines Using Markov Decision Processes with Unknown Parameters  

NASA Astrophysics Data System (ADS)

In this research we apply Markov decision processes with unknown parameters to managing credit lines. We propose a new managing credit lines method which maximizes total discounted reward with reference to a Bayes criterion.

Maeda, Yasunari; Masui, Fumito; Suzuki, Masakiyo

95

Effect of processing parameters on reaction bonding of silicon nitride  

NASA Technical Reports Server (NTRS)

Reaction bonded silicon nitride was developed. The relationship between the various processing parameters and the resulting microstructures was to design and synthesize reaction bonded materials with improved room temperature mechanical properties.

Richman, M. H.; Gregory, O. J.; Magida, M. B.

1980-01-01

96

Estimation of Clustering Parameters Using Gaussian Process Regression  

PubMed Central

We propose a method for estimating the clustering parameters in a Neyman-Scott Poisson process using Gaussian process regression. It is assumed that the underlying process has been observed within a number of quadrats, and from this sparse information the distribution is modelled as a Gaussian process. The clustering parameters are then estimated numerically by fitting to the covariance structure of the model. It is shown that the proposed method is resilient to any sampling regime. The method is applied to simulated two-dimensional clustered populations and the results are compared to a related method from the literature. PMID:25383766

Rigby, Paul; Pizarro, Oscar; Williams, Stefan B.

2014-01-01

97

Optimal levels of process parameters for products with multiple characteristics  

Microsoft Academic Search

The purpose of off-line quality control is to design robust products using robust manufacturing processes before the actual manufacturing of the product. Most of the research work has focused on determining the optimal level settings of process parameters for products with a single quality characteristic. In this paper, we employ the loss function approach to determine the optimal level settings

E. A. ELSAYED; ARGON CHEN

1993-01-01

98

Stainless-steel elbows formed by spin forging  

NASA Technical Reports Server (NTRS)

Large seamless austenitic stainless steel elbows are fabricated by spin forging /rotary shear forming/. A specially designed spin forging tool for mounting on a hydrospin machine has been built for this purpose.

1964-01-01

99

1. MIDDLE FORGE DISPLAY, ACROSS FROM BUILDING NO. 114 on ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. MIDDLE FORGE DISPLAY, ACROSS FROM BUILDING NO. 114 on FARLEY AVE. MARKER ON DISPLAY ITSELF READS: FORGE AND TOOLS, USED AT MIDDLE FORGE LOCATED AT PICATINNY LAKE OUTLETS 1749 TO 1880. NEARBY MARKER READS: THE MIDDLE FORGE. THE MT. HOPE IRONWORKS INCLUDING A TRACT CALLED THE MIDDLE FORGE, SUPPLIED ORDNANCE MATERIAL TO THE CONTINENTAL ARMY IN THE AMERICAN REVOLUTION. GENERAL WASHINGTON INSPECTED THE FACILITY. THE WAR DEPARTMENT PURCHASED THE MIDDLE FORGE PORPERTY FOR AN ARMY POWDER DEPOT IN 1879-80. THE FORGE AND TOOLS WERE RECOVERED AT THE ACTUAL SITE NEAR PICATINNY PEAK. THROUGH THE YEARS, THE MIDDLE FORGE DISPLAY CAME TO BE THE UNOFFICIAL SYMBOL OF PICATINNY ARSENAL. -- HISTORICAL OFFICE NO DATE - Picatinny Arsenal, State Route 15 near I-80, Dover, Morris County, NJ

100

[A method of temperature measurement for hot forging with surface oxide based on infrared spectroscopy].  

PubMed

High temperature large forging is covered with a thick oxide during forging. It leads to a big measurement data error. In this paper, a method of measuring temperature based on infrared spectroscopy is presented. It can effectively eliminate the influence of surface oxide on the measurement of temperature. The method can measure the surface temperature and emissivity of the oxide directly using the infrared spectrum. The infrared spectrum is radiated from surface oxide of forging. Then it can derive the real temperature of hot forging covered with the oxide using the heat exchange equation. In order to greatly restrain interference spectroscopy through included in the received infrared radiation spectrum, three interference filter system was proposed, and a group of optimal gap parameter values using spectral simulation were obtained. The precision of temperature measurement was improved. The experimental results show that the method can accurately measure the surface temperature of high temperature forging covered with oxide. It meets the requirements of measurement accuracy, and the temperature measurement method is feasible according to the experiment result. PMID:22827063

Zhang, Yu-cun; Qi, Yan-de; Fu, Xian-bin

2012-05-01

101

Inclusion engineering for improved fatigue response in forged AISI 4140 steel  

SciTech Connect

Small elemental additions to a steel melt can increase the flow stress of MnS inclusions, making them less deformable during hot working. This condition, called inclusion shape control, is a powerful tool for improving transverse fatigue life of 4140 steel. This research explored the effects of forging on changing the shape and distribution of MnS inclusions, and their role as fatigue initiation sites. The steels in the test matrix were chosen to examine forging effects on inclusions in steel with high and low sulfur levels. One heat had been treated for inclusion shape control. Billets, 127-mm (5-in.) in diameter and 248-mm (9.7-in) high, from bar stock of three heats of inert-gas-shielded/bottom poured (IGS) AISI 4140 steel were upset forged at 1,200 C (2,200 F) to a 50% reduction. A two-dimensional FEM program was used to model the forging process. FEM results at discrete elements were compared with the fatigue response of specimens machined from actual forgings to contain those elements in their gage sections. Both transverse and longitudinal fatigue specimens were machined, and heat treated to obtain a tempered martensite microstructure of approximately 38 HRC. The specimens were tested in tension cycling (R = 0.1) at {sigma}{sub max} = 825 to 965 MPa (120 to 140 ksi). Fatigue results were normalized to a single stress level using a modified Smith-Watson-Topper function. The normalized results were correlated with position in the forgings and calculated effective strains due to forging at those locations. Metallography and fractography were also used to examine inclusion morphologies in regions of low and high local effective strains.

Collins, S.R. [NUPRO Co., Willoughby, OH (United States); Michal, G.M. [Case Western Reserve Univ., Cleveland, OH (United States)

1995-12-31

102

Co-Operative Training in the Sheffield Forging Industry  

ERIC Educational Resources Information Center

Purpose: The purpose of this paper is to give details of an operation carried out in Sheffield to increase the recruitment of young men into the steel forging industry. Design/methodology/approach: The Sheffield Forges Co-operative Training Scheme was designed to encourage boys to enter the forging industry and to provide them with training and…

Duncan, R.

2008-01-01

103

Inverse Problems and Parameter Identification in Image Processing  

E-print Network

4 Inverse Problems and Parameter Identification in Image Processing Jens F. Acker5 , Benjamin Holschneider1 , Jaroslav Hron5 , Claudia Kondermann4 , Michail Kulesh1 , Peter Maass3 , Nadine Olischl¨ager2 for Applied Mathematics, University of Dortmund, Vogelpothsweg 87, 44227 Dortmund, Germany {jens

Garbe, Christoph S.

104

Characteristics of electric parameters in aluminium alloy MAO coating process  

Microsoft Academic Search

Characteristics of electric parameters in the microarc oxidation (MAO) process of aluminium alloy at constant voltage were studied by a homemade data collecting system. The experimental results show that (1) the variations of the cathodic and anodic current amplitudes and the effective working current reflect obviously five different stages in the course of treatment and (2) variations of the dynamic

B H Long; H H Wu; B Y Long; J B Wang; N D Wang; X Y Lü; Z S Jin; Y Z Bai

2005-01-01

105

Determination of Optimal Parameters for SKD11 CNC Turning Process  

Microsoft Academic Search

This study investigated the optimization of a CNC turning process for SKD11 (JIS). The design of experiments (DOE) method with an orthogonal array was applied. Nine experimental runs were performed based on the orthogonal array. The surface properties of roughness average and roughness maximum and the roundness were studied; the analysis of variance (ANOVA) was adapted to investigate which parameters

Chorng-Jyh Tzeng; Yung-Kuang Yang

2008-01-01

106

On the correlations between model process parameters in statistical modeling  

Microsoft Academic Search

1 ABSTRACT Statistical modeling in the design of today's high performance integrated circuits (IC's) is a necessity to produce competitive products with short development time. The use of backward propagation of variance (BPV) (1,2) has proven its worth among other approaches proposed for the statistical modeling. This methodology introduces physically based process and geometry-dependent parameters (PGPs) for each device that

Jirí Slezák; Martin Kejhar

2004-01-01

107

Stellar atmospheric parameter estimation using Gaussian process regression  

NASA Astrophysics Data System (ADS)

As is well known, it is necessary to derive stellar parameters from massive amounts of spectral data automatically and efficiently. However, in traditional automatic methods such as artificial neural networks (ANNs) and kernel regression (KR), it is often difficult to optimize the algorithm structure and determine the optimal algorithm parameters. Gaussian process regression (GPR) is a recently developed method that has been proven to be capable of overcoming these difficulties. Here we apply GPR to derive stellar atmospheric parameters from spectra. Through evaluating the performance of GPR on Sloan Digital Sky Survey (SDSS) spectra, Medium resolution Isaac Newton Telescope Library of Empirical Spectra (MILES) spectra, ELODIE spectra and the spectra of member stars of galactic globular clusters, we conclude that GPR can derive stellar parameters accurately and precisely, especially when we use data preprocessed with principal component analysis (PCA). We then compare the performance of GPR with that of several widely used regression methods (ANNs, support-vector regression and KR) and find that with GPR it is easier to optimize structures and parameters and more efficient and accurate to extract atmospheric parameters.

Bu, Yude; Pan, Jingchang

2015-02-01

108

Effect of Process Parameters on Catalytic Incineration of Solvent Emissions  

PubMed Central

Catalytic oxidation is a feasible and affordable technology for solvent emission abatement. However, finding optimal operation conditions is important, since they are strongly dependent on the application area of VOC incineration. This paper presents the results of the laboratory experiments concerning four most central parameters, that is, effects of concentration, gas hourly space velocity (GHSV), temperature, and moisture on the oxidation of n-butyl acetate. Both fresh and industrially aged commercial Pt/Al2O3 catalysts were tested to determine optimal process conditions and the significance order and level of selected parameters. The effects of these parameters were evaluated by computer-aided statistical experimental design. According to the results, GHSV was the most dominant parameter in the oxidation of n-butyl acetate. Decreasing GHSV and increasing temperature increased the conversion of n-butyl acetate. The interaction effect of GHSV and temperature was more significant than the effect of concentration. Both of these affected the reaction by increasing the conversion of n-butyl acetate. Moisture had only a minor decreasing effect on the conversion, but it also decreased slightly the formation of by products. Ageing did not change the significance order of the above-mentioned parameters, however, the effects of individual parameters increased slightly as a function of ageing. PMID:18584032

Ojala, Satu; Lassi, Ulla; Perämäki, Paavo; Keiski, Riitta L.

2008-01-01

109

Hot forging to produce pore-free near-net-shape ceramic composites  

SciTech Connect

Researchers have demonstrated that it is possible to hot forge ceramic composites without damaging the whisker reinforcement and to reduce flaw size and population. Hot forging was investigated for the systems A1203, A1203/ZrO2, mullite, AlN, and SiC with reinforcements of SiCw and TiB2. The system Al203/SiCw was demonstrated to be forgeable at 1400 C which is 500 C lower than hot pressing temperatures. At high strain rates of greater than 0.1/sec, the density achieved was 99.7 percent with strength values comparable to hot pressing. The hot forging of ceramic-whisker composites offers the opportunity to produce low cost components and, because the process reduces the size and population of flaws, it can result in better mechanical properties with greater reliability.

Shulman, H.S.; Withers, J.C.; Loutfy, R.O.

1988-08-01

110

Parameters in selective laser melting for processing metallic powders  

NASA Astrophysics Data System (ADS)

The paper presents results of studies on Selective Laser Melting. SLM is an additive manufacturing technology which may be used to process almost all metallic materials in the form of powder. Types of energy emission sources, mainly fiber lasers and/or Nd:YAG laser with similar characteristics and the wavelength of 1,06 - 1,08 microns, are provided primarily for processing metallic powder materials with high absorption of laser radiation. The paper presents results of selected variable parameters (laser power, scanning time, scanning strategy) and fixed parameters such as the protective atmosphere (argon, nitrogen, helium), temperature, type and shape of the powder material. The thematic scope is very broad, so the work was focused on optimizing the process of selective laser micrometallurgy for producing fully dense parts. The density is closely linked with other two conditions: discontinuity of the microstructure (microcracks) and stability (repeatability) of the process. Materials used for the research were stainless steel 316L (AISI), tool steel H13 (AISI), and titanium alloy Ti6Al7Nb (ISO 5832-11). Studies were performed with a scanning electron microscope, a light microscopes, a confocal microscope and a ?CT scanner.

Kurzynowski, Tomasz; Chlebus, Edward; Ku?nicka, Bogumi?a; Reiner, Jacek

2012-03-01

111

Thermo-Mechanical Processing Parameters for the INCONEL ALLOY 740  

SciTech Connect

In 2000, a Cooperative Research and Development Agreement (CRADA) was undertaken between the Oak Ridge National Laboratory (ORNL) and the Special Metals Corporation (SMC) to determine the mechanical property response of the IN740 alloy to help establish thermo-mechanical processing parameters for the use of this alloy in supercritical and ultra-critical boiler tubes with the potential for other end uses. SMC had developed an alloy, commercially known as INCONEL alloy 740, which exhibited various beneficial physical, mechanical, and chemical properties. As part of SMC's on-going efforts to optimize this alloy for targeted boiler applications there was a need to develop an understanding of the thermo-mechanical response of the material, characterize the resulting microstructure from this processing, and possibly, utilize models to develop the appropriate processing scheme for this product.

Ludtka, G.M.; Smith, G.

2007-11-19

112

FATIGUE PERFORMANCE COMPARISON AND LIFE PREDICTION OF FORGED STEEL AND DUCTILE CAST IRON CRANKSHAFTS  

Microsoft Academic Search

The objective of this study was to compare the durability of crankshafts from two competing manufacturing processes, as well as to perform dynamic load and stress analysis, and optimization. The crankshafts used in the study were forged steel and ductile cast iron from a one-cylinder gasoline engine. Strain-controlled monotonic and fatigue tests as well as impact tests were performed on

JONATHAN WILLIAMS; FARZIN MONTAZERSADGH; ALI FATEMI

2007-01-01

113

The influence of thickness of CrN coating on the durability of hot forging dies  

NASA Astrophysics Data System (ADS)

This article presents results which enabled the determination of the role of CrN coating and the influence of its thickness on the effectiveness of hybrid layer "nitrided layer / CrN coating" in the process of increasing the durability of forging dies. Dies coated with hybrid layers "nitrided layer / CrN coating" with various CrN coating thickness were — after different maintenance periods — subjected to metallographic testing, 3D shape testing and SEM analysis. Hardness distribution was also determined. The obtained results revealed that for all tested dies, independently from CrN coating thickness, the main mechanisms of their destruction was mechanical and thermal fatigue, and plastic deformation. It has been shown that the main role of CrN coating in the hybrid layer "nitrided layer / PVD coating" is to counteract a high temperature influence the source of which is forging on die material. In order to do so the CrN coating should be characterized by a considerably lower thermal conductivity coefficient to steel and low hardness so that it can efficiently resist fatigue processes in the forging process. Based on testing conducted by means of the sin 2 ? method, it was revealed that internal stresses are vitally important for CrN coating for fatigue resistance of hybrid layer "nitrided layer / CrN coating" during the forging process.

Smolik, Jerzy

2011-06-01

114

Automated, robotized forge-press systems viewed  

NASA Astrophysics Data System (ADS)

Models of industrial robots with load-lifting capacities of 0.08, 0.63, 1.25, 3.5, 10 and 40 kilograms, as well as manipulators with load-lifting capacities of 16 and 50 kilograms for forging rolls were developed. Robot equipment is being developed as the creation of unit design industrial robots. The unit principle of robot design increases their reliability, reduces manufacturing costs, and times for introduction. Requirements for new equipment are discussed.

Khmelnitskiy, M. N.

1985-03-01

115

Drug recrystallization using supercritical anti-solvent (SAS) process with impinging jets: Effect of process parameters  

Microsoft Academic Search

The aim of this study is to improve mixing in supercritical anti-solvent process (SAS) with impinging jets in order to form finer particles of sulfathiazole, a poorly water-soluble drug. The influence of several process parameters upon the powder characteristics is studied. Parameters are jets' velocity (0.25ms?1 to 25.92ms?1), molar ratio solvent\\/CO2 (2.5% to 20%), temperature (313K to 343K), pressure (10MPa

Stéphanie Careno; Olivier Boutin; Elisabeth Badens

116

Determination of Stress-Rupture Parameters for Four Heat-Resisting Alloys  

NASA Technical Reports Server (NTRS)

Stress-rupture data for four heat-resisting alloys are analyzed according to equations of the theory of rate processes. A method for determining the four parameters of structure and composition is demonstrated and the four parameters are determined for each of the alloys: forged S816, cast S816, cast S590, and cast Vitallium. It is concluded that parameters can be determined for an alloy provided sufficient reliable experimental data are available.

Lidman, William G.

1947-01-01

117

Unraveling the Processing Parameters in Friction Stir Welding  

NASA Technical Reports Server (NTRS)

In friction stir welding (FSW), a rotating threaded pin tool is translated along a weld seam, literally stirring the edges of the seam together. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path or paths is required. In this study, various markers are used to trace the flow paths of the metal. X-ray radiographs record the segmentation and position of the wire. Several variations in the trajectories can be differentiated within the weld zone.

Schneider, Judy; Nunes, Arthur C., Jr.

2005-01-01

118

Characteristics, Process Parameters, and Inner Components of Anaerobic Bioreactors  

PubMed Central

The anaerobic bioreactor applies the principles of biotechnology and microbiology, and nowadays it has been used widely in the wastewater treatment plants due to their high efficiency, low energy use, and green energy generation. Advantages and disadvantages of anaerobic process were shown, and three main characteristics of anaerobic bioreactor (AB), namely, inhomogeneous system, time instability, and space instability were also discussed in this work. For high efficiency of wastewater treatment, the process parameters of anaerobic digestion, such as temperature, pH, Hydraulic retention time (HRT), Organic Loading Rate (OLR), and sludge retention time (SRT) were introduced to take into account the optimum conditions for living, growth, and multiplication of bacteria. The inner components, which can improve SRT, and even enhance mass transfer, were also explained and have been divided into transverse inner components, longitudinal inner components, and biofilm-packing material. At last, the newly developed special inner components were discussed and found more efficient and productive. PMID:24672798

Abdelgadir, Awad; Chen, Xiaoguang; Liu, Jianshe; Xie, Xuehui; Zhang, Jian; Zhang, Kai; Wang, Heng; Liu, Na

2014-01-01

119

Sensitivity analysis on parameters and processes affecting vapor intrusion risk.  

PubMed

A one-dimensional numerical model was developed and used to identify the key processes controlling vapor intrusion risks by means of a sensitivity analysis. The model simulates the fate of a dissolved volatile organic compound present below the ventilated crawl space of a house. In contrast to the vast majority of previous studies, this model accounts for vertical variation of soil water saturation and includes aerobic biodegradation. The attenuation factor (ratio between concentration in the crawl space and source concentration) and the characteristic time to approach maximum concentrations were calculated and compared for a variety of scenarios. These concepts allow an understanding of controlling mechanisms and aid in the identification of critical parameters to be collected for field situations. The relative distance of the source to the nearest gas-filled pores of the unsaturated zone is the most critical parameter because diffusive contaminant transport is significantly slower in water-filled pores than in gas-filled pores. Therefore, attenuation factors decrease and characteristic times increase with increasing relative distance of the contaminant dissolved source to the nearest gas diffusion front. Aerobic biodegradation may decrease the attenuation factor by up to three orders of magnitude. Moreover, the occurrence of water table oscillations is of importance. Dynamic processes leading to a retreating water table increase the attenuation factor by two orders of magnitude because of the enhanced gas phase diffusion. PMID:22392684

Picone, Sara; Valstar, Johan; van Gaans, Pauline; Grotenhuis, Tim; Rijnaarts, Huub

2012-05-01

120

Numerical life prediction of mechanical fatigue for hot forging tools  

Microsoft Academic Search

In the forging industry, tools represent an important part in term of production and costs. Enhancing their life cycle is\\u000a then a challenging issue. Several mechanical and thermal mechanisms are responsible for hot forging tools damage such as wear,\\u000a thermal and mechanical fatigue. This work will be focused only on the mechanical fatigue life prediction for hot forging tools.\\u000a Both

Katia Mocellin; Matthieu Ferraro; Vincent Velay; Roland Logé; Farhad Rézaï-Aria

2009-01-01

121

Optimizing noise control strategy in a forging workshop.  

PubMed

In this paper, a computer program based on a genetic algorithm is developed to find an economic solution for noise control in a forging workshop. Initially, input data, including characteristics of sound sources, human exposure, abatement techniques, and production plans are inserted into the model. Using sound pressure levels at working locations, the operators who are at higher risk are identified and picked out for the next step. The program is devised in MATLAB such that the parameters can be easily defined and changed for comparison. The final results are structured into 4 sections that specify an appropriate abatement method for each operator and machine, minimum allowance time for high-risk operators, required damping material for enclosures, and minimum total cost of these treatments. The validity of input data in addition to proper settings in the optimization model ensures the final solution is practical and economically reasonable. PMID:24934422

Razavi, Hamideh; Ramazanifar, Ehsan; Bagherzadeh, Jalal

2014-01-01

122

TRITIUM AGING EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF FORGED STAINLESS STEEL  

SciTech Connect

The fracture toughness properties of Type 21-6-9 stainless steel were measured for forgings in the unexposed, hydrogen-exposed, and tritium-exposed-and-aged conditions. Fracture toughness samples were cut from conventionally-forged and high-energy-rate-forged forward-extruded cylinders and mechanically tested at room temperature using ASTM fracture-toughness testing procedures. Some of the samples were exposed to either hydrogen or tritium gas (340 MPa, 623 K) prior to testing. Tritium-exposed samples were aged for up to seven years and tested periodically in order to measure the effect on fracture toughness of {sup 3}He from radioactive tritium decay. The results show that hydrogen-exposed and tritium-exposed samples had lower fracture- toughness values than unexposed samples and that fracture toughness decreased with increasing decay {sup 3}He content. Forged steels were more resistant to the embrittling effects of tritium and decay {sup 3}He than annealed steels, although their fracture-toughness properties depended on the degree of sensitization that occurred during processing. The fracture process was dominated by microvoid nucleation, growth and coalescence; however, the size and spacing of microvoids on the fracture surfaces were affected by hydrogen and tritium with the lowest-toughness samples having the smallest microvoids and finest spacing.

Morgan, M

2008-04-14

123

The Elements: Forged in Stars  

NSDL National Science Digital Library

All the stars in the universe, including the Sun, are nuclear furnaces fueled by fusion. Beginning with the fusion of hydrogen and continuing with fusion of successively heavier elements, stars form all the naturally occurring elements heavier than hydrogen and helium. This video segment illustrates the critical role that stars play in creating the elements, and describes the process of nucleosynthesis, in which increasingly heavier elements up through iron are formed, at which point the star collapses and explodes in a supernova, during which elements heavier than iron are created. The segment is three minutes forty-two seconds in length. A background essay and discussion questions are included.

124

76 FR 66996 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Forging...  

Federal Register 2010, 2011, 2012, 2013, 2014

...OMB Review; Comment Request; Forging Machines ACTION: Notice...request (ICR) titled, ``Forging Machines,'' to the Office of Management and...document periodic inspections of forging machines, guards, and...

2011-10-28

125

76 FR 31585 - Forged Stainless Steel Flanges From India: Notice of Rescission of Antidumping Duty...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Administration [A-533-809] Forged Stainless Steel Flanges From India: Notice of...the antidumping duty order on forged stainless steel flanges from India. The period...the antidumping duty order on forged stainless steel flanges from India. See...

2011-06-01

126

75 FR 67110 - Forged Stainless Steel Flanges From India and Taiwan  

Federal Register 2010, 2011, 2012, 2013, 2014

...Forged Stainless Steel Flanges From India and Taiwan AGENCY: United States International...on forged stainless steel flanges from India and Taiwan...on forged stainless steel flanges from India and Taiwan would be likely to lead to...

2010-11-01

127

Sustained release microspheres of ropinirole hydrochloride: effect of process parameters.  

PubMed

An emulsion solvent evaporation method was employed to prepare microspheres of ropinirole hydrochloride, a highly water soluble drug, by using ethylcellulose and PEG with the help of 32 full factorial design. The microspheres were made by incorporating the drug in a polar organic solvent, which was emulsified using liquid paraffin as an external oil phase. Effects of various process parameters such as viscosity of the external phase, selection of the internal phase, surfactant selection and selection of stirring speed were studied. Microspheres were evaluated for product yield, encapsulation efficiency and particle size. Various drug/ethylcellulose ratios and PEG concentrations were assayed. In vitro dissolution profiles showed that ethylcellulose microspheres were able to control release of the drug for a period of 12 h. PMID:22202196

Avachat, Amelia M; Bornare, Pralhad N; Dash, Rakesh R

2011-12-01

128

Optimisation of shock absorber process parameters using failure mode and effect analysis and genetic algorithm  

NASA Astrophysics Data System (ADS)

The various process parameters affecting the quality characteristics of the shock absorber during the process were identified using the Ishikawa diagram and by failure mode and effect analysis. The identified process parameters are welding process parameters (squeeze, heat control, wheel speed, and air pressure), damper sealing process parameters (load, hydraulic pressure, air pressure, and fixture height), washing process parameters (total alkalinity, temperature, pH value of rinsing water, and timing), and painting process parameters (flowability, coating thickness, pointage, and temperature). In this paper, the process parameters, namely, painting and washing process parameters, are optimized by Taguchi method. Though the defects are reasonably minimized by Taguchi method, in order to achieve zero defects during the processes, genetic algorithm technique is applied on the optimized parameters obtained by Taguchi method.

Mariajayaprakash, Arokiasamy; Senthilvelan, Thiyagarajan; Vivekananthan, Krishnapillai Ponnambal

2013-07-01

129

The influence of process parameters on electromigration lifetime statistics  

NASA Astrophysics Data System (ADS)

Even after the successful introduction of Cu-based metallization, the electromigration failure risk has remained one of the important reliability concerns for advanced process technologies mostly due to ever increasing operating current densities. The main factors that require understanding are the activation energy related to the dominating diffusion mechanism, the median lifetimes, and the lognormal standard deviation sigma of experimentally obtained lifetime distributions. This study investigates the effect of different process parameters on electromigration lifetime statistics in Cu interconnects. First, the failure distributions of single damascene interconnects with smaller line height are examined, followed by an analysis of the influence of different passivation layers on electromigration statistics. A third part focuses on samples with dual damascene technology. It is observed that the first two process modifications change the median time to failure but do not alter the sigma value. Geometrical and kinetic models developed to describe the electromigration characteristics in Cu/SiN interconnects are successfully employed to explain this observation. These models imply that the lifetime statistics depend on variations in void sizes, geometrical and experimental factors of the electromigration test, and kinetic aspects of the mass transport process. The sigma value in dual damascene interconnects is found to be larger compared to corresponding single damascene structures as a result of an increase in possible void shapes and sizes for void growth into the via in addition to evolution along the line. Furthermore, simulations of expected characteristics of lifetime distributions for future technology nodes using the above models and current electromigration data are discussed.

Hauschildt, M.; Gall, M.; Justison, P.; Hernandez, R.; Ho, P. S.

2008-08-01

130

Advanced rotor forgings for high-temperature steam turbines. Volume 2. Mechanical property evaluation. Final report. [CrMoV steels  

Microsoft Academic Search

Three advanced steel-melting processes - low-sulfur vacuum silicon deoxidation, electroslag remelting, and vacuum carbon deoxidation (VCD) - were applied to produce three CrMoV (ASTM A470, Class 8) steel forgings for steam turbine application. Ingots weighing about 100 t each were produced using these three processes, and rotors were forged with final weights of about 30 t each. Compared to the

V. P. Swaminathan; J. D. Landes

1986-01-01

131

17. Forge building, fuel storage shed, and foundry, 1906 Photocopied ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. Forge building, fuel storage shed, and foundry, 1906 Photocopied from a photograph by Thomas S. Bronson, 'Group at Whitney Factory, 5 November 1906,' NHCHSL. The most reliable view of the fuel storage sheds and foundry, together with a view of the forge building. - Eli Whitney Armory, West of Whitney Avenue, Armory Street Vicinity, Hamden, New Haven County, CT

132

Hot Superplastic Powder Forging for Transparent nanocrystalline Ceramics  

SciTech Connect

The program explored a completely new, economical method of manufacturing nanocrystalline ceramics, Hot Superplastic Powder Forging (HSPF). The goal of the work was the development of nanocrystalline/low porosity optically transparent zirconia/alumina. The high optical transparency should result from lack of grain boundary scattering since grains will be smaller than one tenth the wavelength of light and from elimination of porosity. An important technological potential for this process is manufacturing of envelopes for high-pressure sodium vapor lamps. The technique for fabricating monolithic nanocrystalline material does not begin with powder whose particle diameter is <100 nm as is commonly done. Instead it begins with powder whose particle diameter is on the order of 10-100 microns but contains nanocrystalline crystallites <<100 nm. Spherical particles are quenched from a melt and heat treated to achieve the desired microstructure. Under a moderate pressure within a die or a mold at temperatures of 1100C to 1300C densification is by plastic flow of superplastic particles. A nanocrystalline microstructure results, though some features are greater than 100nm. It was found, for instance, that in the fully dense Al2O3-ZrO2 eutectic specimens that a bicontinuous microstructure exists containing <100 nm ZrO2 particles in a matrix of Al2O3 grains extending over 1-2 microns. Crystallization, growth, phase development and creep during hot pressing and forging were studied for several compositions and so provided some details on development of polycrystalline microstructure from heating quenched ceramics.

Cannon, W. Roger

2006-05-22

133

An axisymmetric forging approach to preform design in ring rolling using a rigid–viscoplastic finite element method  

Microsoft Academic Search

In this paper, a new method for approximately predicting the deformation of material in ring rolling is presented. The plastic flow of material in ring rolling is assumed to be axisymmetric and thus the ring rolling process is considered as a sequence of consecutive forging processes. The problem, having tool velocity as well as material velocity field as unknown variables,

M. S. Joun; J. H. Chung; R. Shivpuri

1998-01-01

134

Meta-Model Based Optimisation Algorithms for Robust Optimization of 3D Forging Sequences  

SciTech Connect

In order to handle costly and complex 3D metal forming optimization problems, we develop a new optimization algorithm that allows finding satisfactory solutions within less than 50 iterations (/function evaluation) in the presence of local extrema. It is based on the sequential approximation of the problem objective function by the Meshless Finite Difference Method (MFDM). This changing meta-model allows taking into account the gradient information, if available, or not. It can be easily extended to take into account uncertainties on the optimization parameters. This new algorithm is first evaluated on analytic functions, before being applied to a 3D forging benchmark, the preform tool shape optimization that allows minimizing the potential of fold formation during the two-stepped forging sequence.

Fourment, Lionel [CEMEF, Ecole des Mines de Paris, BP 207, 06 904 Sophia Antipolis Cedex (France)

2007-04-07

135

Technical bases for precipitate hydrolysis process operating parameters  

SciTech Connect

This report provides the experimental data and rationale in support of the operating parameters for precipitate hydrolysis specified in WSRC-RP-92737. The report is divided into two sections, the first dealing with lab-scale precipitate hydrolysis experimentation while the second part addresses large-scale runs conducted to demonstrate the revised operating parameters in the Precipitate Hydrolysis Experimental Facility (PHEF).

Bannochie, C.J.

1992-10-05

136

Thermomechanical Response of the Rotary Forged Wha Over a Wide Range of Strain Rates and Temperatures  

NASA Astrophysics Data System (ADS)

This paper is to understand and model the thermomechanical response of the rotary forged WHA, uniaxial compression and tension tests are performed on cylindrical samples, using a material testing machines and the split Hopkinson bar technique. True strains exceeding 40% are achieved in these tests over the range of strain rates from 0.001/s to about 7,000/s, and at initial temperatures from 77K to 1,073K. The results show: 1) the WHA displays a pronounced changing orientation due to mechanical processing, that is, the material is inhomogeneous along the section; 2) the dynamic strain aging occurs at temperatures over 700K and in a strain rate of 10-3 1/s; 3) failure strains decrease with increasing strain rate under uniaxial tension, it is about 1.2% at a strain rate of 1,000 1/s; and 4) flow stress of WHA strongly depends on temperatures and strain rates. Finally, based on the mechanism of dislocation motion, the parameters of a physically-based model are estimated by the experimental results. A good agreement between the modeling prediction and experiments was obtained.

Guo, W. G.; Qu, C.; Liu, F. L.

137

Technical bases for precipitate hydrolysis process operating parameters. Revision 1  

SciTech Connect

This report provides the experimental data and rationale in support of the operating parameters for tetraphenylborate precipitate hydrolysis specified in WSRC-RP-92-737. The report is divided into two sections, the first dealing with lab-scale precipitate hydrolysis experimentation while the second part addresses large-scale runs conducted to demonstrate the revised operating parameters in the Precipitate Hydrolysis Experimental Facility (PHEF). The program was in conjunction with reducing the nitrite ion level in DWPF feed.

Bannochie, C.J.; Lambert, D.P.

1992-11-09

138

Technical bases for precipitate hydrolysis process operating parameters  

SciTech Connect

This report provides the experimental data and rationale in support of the operating parameters for tetraphenylborate precipitate hydrolysis specified in WSRC-RP-92-737. The report is divided into two sections, the first dealing with lab-scale precipitate hydrolysis experimentation while the second part addresses large-scale runs conducted to demonstrate the revised operating parameters in the Precipitate Hydrolysis Experimental Facility (PHEF). The program was in conjunction with reducing the nitrite ion level in DWPF feed.

Bannochie, C.J.; Lambert, D.P.

1992-11-09

139

Texture Development During Equal Channel Angular Forging of BCC Metals  

SciTech Connect

Equal channel angular forging (ECAF) has been proposed as a severe plastic deformation technique for processing metals, alloys, and composites [e.g. Segal, 1995] (Fig. 1). The technique offers two capabilities of practical interest: a high degree of strain can be introduced with no change in the cross-sectional dimensions of the work-piece, hence, even greater strains can be introduced by re-inserting the work-piece for further deformation during subsequent passes through the ECAF die. Additionally, the deformation is accomplished by simple shear (like torsion of a short tube) on a plane whose orientation, with respect to prior deformations, can be controlled by varying the processing route. There is a nomenclature that has developed in the literature for the typical processing routes: A: no rotations; B{sub A}: 90 degrees CW (clockwise), 90 degrees CCW (counterclockwise), 9O degrees CW, 90 degrees CCW...; Bc: 90 degrees CW, 90 degrees CW, 90 degrees CW...; and C: 180 degrees, 18 0 degrees.... The impact of processing route on the subsequent microstructure [Ferasse, Segal, Hartwig and Goforth, 1997; Iwahashi, Horita, Nemoto and Langdon, 1996] and texture [Gibbs, Hartwig, Cornwell, Goforth and Payzant, 1998] has been the subject of numerous experimental studies.

Agnew, S.R.

1999-08-08

140

FEA Based Tool Life Quantity Estimation of Hot Forging Dies Under Cyclic Thermo-Mechanical Loads  

NASA Astrophysics Data System (ADS)

Hot forging dies are exposed during service to a combination of cyclic thermo-mechanical, tribological and chemical loads. Besides abrasive and adhesive wear on the die surface, fatigue crack initiation with subsequent fracture is one of the most frequent causes of failure. In order to extend the tool life, the finite element analysis (FEA) may serve as a means for process design and process optimisation. So far the FEA based estimation of the production cycles until initial cracking is limited as tool material behaviour due to repeated loading is not captured with the required accuracy. Material models which are able to account for cyclic effects are not verified for the fatigue life predictions of forging dies. Furthermore fatigue properties from strain controlled fatigue tests of relevant hot work steels are to date not available to allow for a close-to-reality fatigue life prediction. Two industrial forging processes, where clear fatigue crack initiation has been observed are considered for a fatigue analysis. For this purpose the relevant tool components are modelled with elasto-plastic material behaviour. The predicted sites, where crack initiation occurs, agree with the ones observed on the real die component.

Behrens, B.-A.; Bouguecha, A.; Schäfer, F.; Hadifi, T.

2011-01-01

141

The effects of STI process parameters on the integrity of dual gate oxides  

Microsoft Academic Search

The reliability of dual gate oxide has been investigated in terms of dual gate oxide and shallow trench isolation (STI) process parameters. The thick oxide constructed by the dual gate oxide process shows intrinsic inferior quality to single-step grown thin oxide due to differences in its fabrication process, mainly the double-growth scheme. A larger susceptibility to STI process parameters is

Hoon Lim; Seung-Jae Lee; Jong-Mil Youn; Tae-Hong Ha; Jin-Ho Kim; Bong-Hyun Choi; Ki-Joon Kim; Ho-Jin Kim; Kyeong-Tae Kim; Hyun-Geun Byun

2001-01-01

142

Numerical Investigation of Process Parameters on External Inversion of Thin-Walled Tubes  

NASA Astrophysics Data System (ADS)

In this paper, a computational study of development of external inversion mode of deformation of round-metallic aluminum tubes over a fixed profile die is presented. Inversion mode of deformation is analyzed in detail by using a finite element code FORGE2. The proposed finite element model for this purpose idealizes the deformation as axisymmetric. Six-noded triangular elements are used to discretize the domain. The material is modeled as rigid-viscoplastic. Typical variations of the equivalent strain rate and equivalent strain along the length of the deforming tube are studied to predict the development of inversion mode of deformation. The influence of the friction present at the contact interface between the tube and the die is also examined to suggest a successful inversion of tube. Energy absorbed in overcoming the frictional stresses between the tube-die interfaces is compared with the total energy required in the inversion of tube. A few predicted results which include the geometry of inverted tube load-compression variation during inversion process are compared with their experimental counterparts to validate the computational model.

Gupta, P. K.

2014-08-01

143

Roll compaction process modeling: Transfer between equipment and impact of process parameters.  

PubMed

In this study, the roll compaction of an intermediate drug load formulation was performed using horizontally and vertically force fed roll compactors. The horizontally fed roll compactor was equipped with an instrumented roll technology allowing the direct measurement of normal stress at the roll surface, while the vertically fed roll compactor was equipped with a force gauge between the roll axes. Furthermore, characterization of ribbons, granules and tablets was also performed. Ribbon porosity was primarily found to be a function of normal stress, exhibiting a quadratic relationship thereof. A similar quadratic relationship was also observed between roll force and ribbon porosity of the vertically fed roll compactor. The predicted peak pressure (Pmax) using the Johanson model was found to be higher than the measured normal stress, however, the predicted Pmax correlated well with the ribbon relative density/porosity and the majority of downstream properties of granules and tablets, demonstrating its use as a scale-independent parameter. A latent variable model was developed for both the horizontal and vertical fed roll compactors to express ribbon porosity as a function of geometric and process parameters. The model validation, performed with new data, resulted in overall good predictions. This study successfully demonstrated the scale up/transfer between two different roll compactors and revealed that the combined use of design of experiments, latent variable models and in silico predictions result in better understanding of the critical process parameters in roll compaction. PMID:25701630

Souihi, Nabil; Reynolds, Gavin; Tajarobi, Pirjo; Wikström, Håkan; Haeffler, Gunnar; Josefson, Mats; Trygg, Johan

2015-04-30

144

Sensor Data Acquisition and Processing Parameters for Human Activity Classification  

PubMed Central

It is known that parameter selection for data sampling frequency and segmentation techniques (including different methods and window sizes) has an impact on the classification accuracy. For Ambient Assisted Living (AAL), no clear information to select these parameters exists, hence a wide variety and inconsistency across today's literature is observed. This paper presents the empirical investigation of different data sampling rates, segmentation techniques and segmentation window sizes and their effect on the accuracy of Activity of Daily Living (ADL) event classification and computational load for two different accelerometer sensor datasets. The study is conducted using an ANalysis Of VAriance (ANOVA) based on 32 different window sizes, three different segmentation algorithm (with and without overlap, totaling in six different parameters) and six sampling frequencies for nine common classification algorithms. The classification accuracy is based on a feature vector consisting of Root Mean Square (RMS), Mean, Signal Magnitude Area (SMA), Signal Vector Magnitude (here SMV), Energy, Entropy, FFTPeak, Standard Deviation (STD). The results are presented alongside recommendations for the parameter selection on the basis of the best performing parameter combinations that are identified by means of the corresponding Pareto curve. PMID:24599189

Bersch, Sebastian D.; Azzi, Djamel; Khusainov, Rinat; Achumba, Ifeyinwa E.; Ries, Jana

2014-01-01

145

27 CFR 447.22 - Forgings, castings, and machined bodies.  

Code of Federal Regulations, 2010 CFR

...Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION IMPORTATION OF ARMS, AMMUNITION AND IMPLEMENTS OF WAR The U.S. Munitions Import List § 447.22 Forgings, castings,...

2010-04-01

146

DETAIL VIEW OF BLACKSMITH'S FORGE AND WORK AREA ON WEST ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL VIEW OF BLACKSMITH'S FORGE AND WORK AREA ON WEST SIDE OF UPPER TRAM TERMINAL, LOOKING EAST. FORGE IS IN FOREGROUND, WITH THE ANVIL BLOCK JUST TO THE RIGHT AND BEHIND IT. A TRAM CAR IS UPSIDE DOWN TO THE LEFT OF THE FORGE. THE PIPE GOING INTO THE FORGE ON THE RIGHT CARRIED COMPRESSED AIR TO BLOW THE COALS. AT CENTER RIGHT ON THE TRAM TERMINAL ARE THE OPENING AND CLOSING MECHANISMS FOR THE ORE BUCKETS. AT CENTER LEFT IS A BRAKE WHEEL. THE ANCHOR POINTS FOR THE STATIONARY TRAM CABLES ARE JUST BELOW THIS WHEEL. THE FRONT END OF THE TERMINAL IS JUST OFF FRAME ON THE RIGHT. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

147

The Processes and Parameters of Fine Art Phd Examination  

ERIC Educational Resources Information Center

The merger of art schools into academic institutions and the consequent proliferation of higher degree courses in the visual arts has created pressure for these courses to justify that their research content 'measures up' to more traditional research practices. This study aimed to identify the parameters for PhD examination and research practices…

Dally, K.; Holbrook, A.; Graham, A.; Lawry, M.

2004-01-01

148

Estimation of physical parameters for dynamic processes with application to an industrial robot  

Microsoft Academic Search

The unknown parameters of physical laws which govern the dynamics of processes can be gained from measured input and output signals in a two step procedure. First the parameters of differential equations are estimated and then the physical parameters are calculated based on algebraic relations. After considering the model structures a suitable parameter estimation method for continuous time signals is

R. ISERMANN

1992-01-01

149

The Networked Forge: New Environments for Libre Software Development  

Microsoft Academic Search

Libre (free, open source) software forges (sites hosting the development infrastructure for a collection of projects) have\\u000a been stable in architecture, services and concept since they become popular during the late 1990s. During this time several\\u000a problems that cannot be solved without dramatic design changes have become evident. To overcome them, we propose a new concept,\\u000a the “networked forge”, focused

Jesús M. González-barahona; Andrés Leonardo Martínez; Alvaro Polo; Juan José Hierro; Marcos Reyes; Javier Soriano; Rafael Fernández

2008-01-01

150

Quenching and Cold-Work Residual Stresses in Aluminum Hand Forgings : Contour Method Measurement and FEM Prediction  

SciTech Connect

The cold-compression stress relief process used to reduce the quench-induced stresses in high-strength aerospace aluminum alloy forgings does not fully relieve the stresses. This study measured and predicted the residual stress in 7050-T74 (solution heat treated, quenched, and artificially overaged) and 7050-T7452 (cold compressed prior to aging) hand forgings. The manufacturing process was simulated by finite element analysis. First, a thermal analysis simulated the quench using appropriate thermal boundary conditions and temperature dependent material properties. Second, a structural analysis used the thermal history and a temperature and strain-rate dependent constitutive model to predict the stresses after quenching. Third, the structural analysis was continued to simulate the multiple cold compressions of the stress relief process. Experimentally, the residual stresses in the forgings were mapped using the contour method, which involved cutting the forgings using wire EDM and then measuring the contour of the cut surface using a CMM. Multiple cuts were used to map different stress components. The results show a spatially periodic variation of stresses that results from the periodic nature of the cold work stress relief process. The results compare favorably with the finite element prediction of the stresses.

Prime, M. B. (Michael B.); Newborn, M. A. (Mark A.); Balog, J. A. (John A.)

2003-01-01

151

A CAPP framework with optimized process parameters for rotational components  

Microsoft Academic Search

Process planning, as a critical stage integrating the design and manufacturing phase in a manufacturing environment, has been automated to meet the needs for higher productivity and lower production cost. Being an input to various systems such as scheduling and routing, process planning results are of great importance in the manufacturing stage. Though feature extraction and sequence optimization have been

R. Siva Sankar; P. Asokan; G. Prabhaharan; A. V. Phani

2008-01-01

152

Parameter Optimization Design for Touch Panel Laser Cutting Process  

Microsoft Academic Search

Cutting is an essential process in touch panel manufacturing, which concerns the effectiveness of whole touch panel manufacturing process and reliability of final application products. An alternative is laser cutting technology, which is expected to eclipse conventional cutting method in terms of cost and quality. The laser cutting quality of touch panel is determined by the appropriation of value settings

Chao-Ton Su; Yu-Hsiang Hsiao; Chia-Chin Chang

2012-01-01

153

Forging the future: the public health imperative.  

PubMed Central

During the 1980s, national policy promoted military expenditures and downsized domestic programs. These priorities, along with tax reform and deregulation, created a "domestic gulf crisis" with a new wave of vulnerable populations--poor children, the homeless, the elderly, and the uninsured. Our lack of a national health program compounds the problem. The 1990s will be a decade of change and challenge. To forge a healthier and stronger future for our nation, we must implement five public health imperatives: (1) We must have a national health program that is universal, comprehensive, and prevention-oriented, with built-in assurances for quality, efficiency, and a strong public health infrastructure. (2) We must have a comprehensive national health education and promotion program for all schoolchildren. (3) Women must have freedom of choice. (4) Prevention and public health must become one of our country's highest health priorities. (5) The federal government must increase its leadership, commitments, and resources to reach the goals set forth in Healthy Communities 2000 and Healthy People 2000. PMID:8484444

Allukian, M

1993-01-01

154

Adaptive filter solution for processing lidar returns: optical parameter estimation.  

PubMed

Joint estimation of extinction and backscatter simulated profiles from elastic-backscatter lidar return signals is tackled by means of an extended Kalman filter (EKF). First, we introduced the issue from a theoretical point of view by using both an EKF formulation and an appropriate atmospheric stochastic model; second, it is tested through extensive simulation and under simplified conditions; and, finally, a first real application is discussed. An atmospheric model including both temporal and spatial correlation features is introduced to describe approximate fluctuation statistics in the sought-after atmospheric optical parameters and hence to include a priori information in the algorithm. Provided that reasonable models are given for the filter, inversion errors are shown to depend strongly on the atmospheric condition (i.e., the visibility) and the signal-to-noise ratio along the exploration path in spite of modeling errors in the assumed statistical properties of the atmospheric optical parameters. This is of advantage in the performance of the Kalman filter because they are often the point of most concern in identification problems. In light of the adaptive behavior of the filter and the inversion results, the EKF approach promises a successful alternative to present-day nonmemory algorithms based on exponential-curve fitting or differential equation formulations such as Klett's method. PMID:18301520

Rocadenbosch, F; Vázquez, G; Comerón, A

1998-10-20

155

Evolution of the Ultrasonic Inspection of Heavy Rotor Forgings Over the Last Decades  

NASA Astrophysics Data System (ADS)

All types of heavy forgings that are used in energy machine industry, rotor shafts as well as discs, retaining rings or tie bolts are subject to extensive nondestructive inspections before they are delivered to the customer. Due to the availability of the parts in simple shapes, these forgings are very well suited for full volmetric inspections using ultrasound. In the beginning, these inspections were carried out manually, using straight beam probes and analogue equipment. Higher requirements in reliability, efficiency, safety and power output in the machines have lead to higher requirements for the ultrasonic inspection in the form of more scanning directions, higher sensitivity demands and improved documentation means. This and the increasing use of high alloy materials for ever growing parts, increase the need for more and more sophisticated methods for testing the forgings. Angle scans and sizing technologies like DGS have been implemented, and for more than 15 years now, mechanized and automated inspections have gained importance since they allow better documentation as well as easier evaluation of the recorded data using different views (B- C- or D-Scans), projections or tomography views. The latest major development has been the availability of phased array probes to increase the flexibility of the inspection systems. Many results of the ongoing research in ultrasonic's have not been implemented yet. Today's availability of fast computers, large and fast data storages allows saving RF inspection data and applying sophisticated signal processing methods. For example linear diffraction tomography methods like SAFT offer tools for 3D reconstruction of inspection data, simplifying sizing and locating of defects as well as for improving signal to noise ratios. While such methods are already applied in medical ultrasonic's, they are still to be implemented in the steel industry. This paper describes the development of the ultrasonic inspection of heavy forgings from the beginning up to today at the example of Saarschmiede GmbH explains the difficulties in implementing changes and gives an outlook over the current progression.

Zimmer, A.; Vrana, J.; Meiser, J.; Maximini, W.; Blaes, N.

2010-02-01

156

Dimensionless Numbers Expressed in Terms of Common CVD Process Parameters  

NASA Technical Reports Server (NTRS)

A variety of dimensionless numbers related to momentum and heat transfer are useful in Chemical Vapor Deposition (CVD) analysis. These numbers are not traditionally calculated by directly using reactor operating parameters, such as temperature and pressure. In this paper, these numbers have been expressed in a form that explicitly shows their dependence upon the carrier gas, reactor geometry, and reactor operation conditions. These expressions were derived for both monatomic and diatomic gases using estimation techniques for viscosity, thermal conductivity, and heat capacity. Values calculated from these expressions compared well to previously published values. These expressions provide a relatively quick method for predicting changes in the flow patterns resulting from changes in the reactor operating conditions.

Kuczmarski, Maria A.

1999-01-01

157

A new solution to parameter adaptive estimation of random processes  

NASA Technical Reports Server (NTRS)

This paper is concerned with the development of an adaptive state estimator that is capable of tracking switched linear plants that undergo rapid configuration changes. The particular adaptive estimator developed here is called the Sliding Window Detector/Estimator (SWDE) algorithm. Unlike previous algorithms, the SWDE algorithm is designed specifically for the switched-linear plant problem. It uses a joint detection/estimation approach to give a very close approximation to the unrealizable optimum switched-linear estimator. An extremely reliable and accurate estimator can be constructed by combining a modified Parameter Adaptive Estimation (PAE) algorithm with SWDE. The algorithm has been fully verified by extensive computer simulation, and the implementation advantages afforded by this method make it suitable for use in a wide variety of applications.

Zwicke, P. E.; Van Landingham, H. F.; Moose, R. L.

1982-01-01

158

Implant for in-vivo parameter monitoring, processing and transmitting  

DOEpatents

The present invention relates to a completely implantable intracranial pressure monitor, which can couple to existing fluid shunting systems as well as other internal monitoring probes. The implant sensor produces an analog data signal which is then converted electronically to a digital pulse by generation of a spreading code signal and then transmitted to a location outside the patient by a radio-frequency transmitter to an external receiver. The implanted device can receive power from an internal source as well as an inductive external source. Remote control of the implant is also provided by a control receiver which passes commands from an external source to the implant system logic. Alarm parameters can be programmed into the device which are capable of producing an audible or visual alarm signal. The utility of the monitor can be greatly expanded by using multiple pressure sensors simultaneously or by combining sensors of various physiological types.

Ericson, Milton N. (Knoxville, TN); McKnight, Timothy E. (Greenback, TN); Smith, Stephen F. (London, TN); Hylton, James O. (Clinton, TN)

2009-11-24

159

Texture evolution in Al-Li 2195 alloy during net shape roll forging  

SciTech Connect

The quest to manufacture low-cost, large complex structures with minimum material wastage has instigated research into near-net shape (NNS) technologies. In this paper, the microstructural and texture evolution in Al-Li 2195 alloy resulting from a specific NNS processing called roll forging was evaluated. The processing consists of five stages and combines conventional ingot conversion (stages I and II), back extrusion (stage III) and ring rolling to produce hollow cylinder (stage IV). Considerable potential exists for the property enhancement of the components produced by this processing method if a better understanding of the evolution of microstructure and texture is developed.

Kalu, P.N.; Zhang, Lan [FAMU-FSU Coll. of Engineering, Tallahassee, FL (United States). Dept. of Mechanical Engineering] [FAMU-FSU Coll. of Engineering, Tallahassee, FL (United States). Dept. of Mechanical Engineering

1998-06-12

160

Optimization of process parameters for the manufacturing of rocket casings: A study using processing maps  

NASA Astrophysics Data System (ADS)

Maraging steels possess ultrahigh strength combined with ductility and toughness and could be easily fabricated and heat-treated. Bulk metalworking of maraging steels is an important step in the component manufacture. To optimize the hot-working parameters (temperature and strain rate) for the ring rolling process of maraging steel used for the manufacture of rocket casings, a systematic study was conducted to characterize the hot working behavior by developing processing maps for ?-iron and an indigenous 250 grade maraging steel. The hot deformation behavior of binary alloys of iron with Ni, Co, and Mo, which are major constituents of maraging steel, is also studied. Results from the investigation suggest that all the materials tested exhibit a domain of dynamic recrystallization (DRX). From the instability maps, it was revealed that strain rates above 10 s-1 are not suitable for hot working of these materials. An important result from the stress-strain behavior is that while Co strengthens ?-iron, Ni and Mo cause flow softening. Temperatures around 1125 °C and strain rate range between 0.001 and 0.1 s-1 are suitable for the hot working of maraging steel in the DRX domain. Also, higher strain rates may be used in the meta-dynamic recrystallization domain above 1075 °C for high strain rate applications such as ring rolling. The microstructural mechanisms identified from the processing maps along with grain size analyses and hot ductility measurements could be used to design hot-working schedules for maraging steel.

Avadhani, G. S.

2003-12-01

161

A Multiresolution Method for Parameter Estimation of Diffusion Processes  

PubMed Central

Diffusion process models are widely used in science, engineering and finance. Most diffusion processes are described by stochastic differential equations in continuous time. In practice, however, data is typically only observed at discrete time points. Except for a few very special cases, no analytic form exists for the likelihood of such discretely observed data. For this reason, parametric inference is often achieved by using discrete-time approximations, with accuracy controlled through the introduction of missing data. We present a new multiresolution Bayesian framework to address the inference difficulty. The methodology relies on the use of multiple approximations and extrapolation, and is significantly faster and more accurate than known strategies based on Gibbs sampling. We apply the multiresolution approach to three data-driven inference problems – one in biophysics and two in finance – one of which features a multivariate diffusion model with an entirely unobserved component. PMID:25328259

Kou, S. C.; Olding, Benjamin P.; Lysy, Martin; Liu, Jun S.

2014-01-01

162

The Effects of Forming Parameters on Conical Ring Rolling Process  

PubMed Central

The plastic penetration condition and biting-in condition of a radial conical ring rolling process with a closed die structure on the top and bottom of driven roll, simplified as RCRRCDS, were established. The reasonable value range of mandrel feed rate in rolling process was deduced. A coupled thermomechanical 3D FE model of RCRRCDS process was established. The changing laws of equivalent plastic strain (PEEQ) and temperature distributions with rolling time were investigated. The effects of ring's outer radius growth rate and rolls sizes on the uniformities of PEEQ and temperature distributions, average rolling force, and average rolling moment were studied. The results indicate that the PEEQ at the inner layer and outer layer of rolled ring are larger than that at the middle layer of ring; the temperatures at the “obtuse angle zone” of ring's cross-section are higher than those at “acute angle zone”; the temperature at the central part of ring is higher than that at the middle part of ring's outer surfaces. As the ring's outer radius growth rate increases at its reasonable value ranges, the uniformities of PEEQ and temperature distributions increase. Finally, the optimal values of the ring's outer radius growth rate and rolls sizes were obtained. PMID:25202716

Meng, Wen; Zhao, Guoqun; Guan, Yanjin

2014-01-01

163

The effects of forming parameters on conical ring rolling process.  

PubMed

The plastic penetration condition and biting-in condition of a radial conical ring rolling process with a closed die structure on the top and bottom of driven roll, simplified as RCRRCDS, were established. The reasonable value range of mandrel feed rate in rolling process was deduced. A coupled thermomechanical 3D FE model of RCRRCDS process was established. The changing laws of equivalent plastic strain (PEEQ) and temperature distributions with rolling time were investigated. The effects of ring's outer radius growth rate and rolls sizes on the uniformities of PEEQ and temperature distributions, average rolling force, and average rolling moment were studied. The results indicate that the PEEQ at the inner layer and outer layer of rolled ring are larger than that at the middle layer of ring; the temperatures at the "obtuse angle zone" of ring's cross-section are higher than those at "acute angle zone"; the temperature at the central part of ring is higher than that at the middle part of ring's outer surfaces. As the ring's outer radius growth rate increases at its reasonable value ranges, the uniformities of PEEQ and temperature distributions increase. Finally, the optimal values of the ring's outer radius growth rate and rolls sizes were obtained. PMID:25202716

Meng, Wen; Zhao, Guoqun; Guan, Yanjin

2014-01-01

164

Catching sparks from well-forged neutralinos  

NASA Astrophysics Data System (ADS)

In this paper we present a new search technique for electroweakinos, the superpartners of electroweak gauge and Higgs bosons, based on final states with missing transverse energy, a photon, and a dilepton pair, ?+?-+? +E T . Unlike traditional electroweakino searches, which perform best when m?˜2 ,3 0-m?˜1 0,m?˜ ±-m?˜1 0>mZ , our search favors nearly degenerate spectra; degenerate electroweakinos typically have a larger branching ratio to photons, and the cut m???mZ effectively removes on shell Z boson backgrounds while retaining the signal. This feature makes our technique optimal for "well-tempered" scenarios, where the dark matter relic abundance is achieved with interelectroweakino splittings of ˜20 - 70 GeV . Additionally, our strategy applies to a wider range of scenarios where the lightest neutralinos are almost degenerate, but only make up a subdominant component of the dark matter—a spectrum we dub well forged. Focusing on bino-Higgsino admixtures, we present optimal cuts and expected efficiencies for several benchmark scenarios. We find bino-Higgsino mixtures with m?˜2 ,3 0?190 GeV and m?˜2 ,3 0-m?˜1 0?30 GeV can be uncovered after roughly 600 fb-1 of luminosity at the 14 TeV LHC. Scenarios with lighter states require less data for discovery, while scenarios with heavier states or larger mass splittings are harder to discriminate from the background and require more data. Unlike many searches for supersymmetry, electroweakino searches are one area where the high luminosity of the next LHC run, rather than the increased energy, is crucial for discovery.

Bramante, Joseph; Delgado, Antonio; Elahi, Fatemeh; Martin, Adam; Ostdiek, Bryan

2014-11-01

165

Parameter Optimisation of a Vacuum Plasma Spraying Process Using Boron Carbide  

NASA Astrophysics Data System (ADS)

This study determines the optimal processing parameters for vacuum plasma spraying boron carbide (B4C), employing an integrated approach based on the Taguchi design method, a neural network, and a genetic algorithm (GA). The proposed method comprises two stages. In the first stage, the Taguchi design method is used to establish a preliminary solution for the optimal set of processing parameters. In the second stage, the experimental results acquired from the Taguchi trials are used to construct a neural network model of the spraying process. A GA is then used to establish the optimal combination of processing parameters. The experimental results show that the coating void content of the specimen prepared using the processing parameters identified by the GA is significantly lower than that of the specimen prepared using the processing parameters identified by the Taguchi method alone.

Lin, Chun-Ming

2012-09-01

166

A stochastic process approach of the drake equation parameters  

NASA Astrophysics Data System (ADS)

The number N of detectable (i.e. communicating) extraterrestrial civilizations in the Milky Way galaxy is usually calculated by using the Drake equation. This equation was established in 1961 by Frank Drake and was the first step to quantifying the Search for ExtraTerrestrial Intelligence (SETI) field. Practically, this equation is rather a simple algebraic expression and its simplistic nature leaves it open to frequent re-expression. An additional problem of the Drake equation is the time-independence of its terms, which for example excludes the effects of the physico-chemical history of the galaxy. Recently, it has been demonstrated that the main shortcoming of the Drake equation is its lack of temporal structure, i.e., it fails to take into account various evolutionary processes. In particular, the Drake equation does not provides any error estimation about the measured quantity. Here, we propose a first treatment of these evolutionary aspects by constructing a simple stochastic process that will be able to provide both a temporal structure to the Drake equation (i.e. introduce time in the Drake formula in order to obtain something like N(t)) and a first standard error measure.

Glade, Nicolas; Ballet, Pascal; Bastien, Olivier

2012-04-01

167

The Influence of Process Parameters on Lactic Acid Fermentation in Laboratory Scale Fermenter  

Microsoft Academic Search

The purpose of this study was to study the influence of process parameters on the Lactic Acid Fermentation by Lactobacillus rhamnosus in laboratory scale fermenter. The experiment was designed by Taguchi Method using STATISTICA software. Three parameters have been chosen as the main parameters that affect significantly to the growth of L. rhamnosus; the agitation speed of the impeller, dissolve

Maizirwan Mel; Mohd Ismail Abdul Karim; Parveen Jamal; Mohamad Ramlan Mohamed Salleh; Ruzi Aini Zakaria

2006-01-01

168

Study of the microstructure and mechanical properties of Al6061 aluminum alloys rheo-forged by vacuum pump  

Microsoft Academic Search

Rheo-forging of metal offers not only superior mechanical strength but also requires significantly lower machine loads than solid forming processes. In order to produce semi-solid materials that have the desired microstructure, a stirring process is applied during solidification from molten state. During this process, air indraft can occasionally result in degradation of the mechanical properties of the semi-solid materials. As

H. H. Kim; C. G. Kang

2008-01-01

169

High Temperature, Slow Strain Rate Forging of Advanced Disk Alloy ME3  

NASA Technical Reports Server (NTRS)

The advanced disk alloy ME3 was designed in the HSR/EPM disk program to have extended durability at 1150 to 1250 F in large disks. This was achieved by designing a disk alloy and process producing balanced monotonic, cyclic, and time-dependent mechanical properties. combined with robust processing and manufacturing characteristics. The resulting baseline alloy, processing, and supersolvus heat treatment produces a uniform, relatively fine mean grain size of about ASTM 7, with as-large-as (ALA) grain size of about ASTM 3. There is a long term need for disks with higher rim temperature capabilities than 1250 F. This would allow higher compressor exit (T3) temperatures and allow the full utilization of advanced combustor and airfoil concepts under development. Several approaches are being studied that modify the processing and chemistry of ME3, to possibly improve high temperature properties. Promising approaches would be applied to subscale material, for screening the resulting mechanical properties at these high temperatures. n obvious path traditionally employed to improve the high temperature and time-dependent capabilities of disk alloys is to coarsen the grain size. A coarser grain size than ASTM 7 could potentially be achieved by varying the forging conditions and supersolvus heat treatment. The objective of this study was to perform forging and heat treatment experiments ("thermomechanical processing experiments") on small compression test specimens of the baseline ME3 composition, to identify a viable forging process allowing significantly coarser grain size targeted at ASTM 3-5, than that of the baseline, ASTM 7.

Gabb, Timothy P.; OConnor, Kenneth

2001-01-01

170

The Application of Multi-layer Perception Networks in the Parameters Optimization of Stamping Forming Process  

Microsoft Academic Search

In the stamping process of high-strength steels, how to adjust each processing parameters to meet the needs of parts deformed is the key problem to be solved in the craft of stamping forming. The main work in this paper is to gain the optimum parameters by making use of neural network to fit experimental datum of stamping. In the experiment

Fengli Huang

2008-01-01

171

HepForge: A lightweight development environment for HEP software  

E-print Network

Setting up the infrastructure to manage a software project can become a task as significant writing the software itself. A variety of useful open source tools are available, such as Web-based viewers for version control systems, "wikis" for collaborative discussions and bug-tracking systems, but their use in high-energy physics, outside large collaborations, is insubstantial. Understandably, physicists would rather do physics than configure project management tools. We introduce the CEDAR HepForge system, which provides a lightweight development environment for HEP software. Services available as part of HepForge include the above-mentioned tools as well as mailing lists, shell accounts, archiving of releases and low-maintenance Web space. HepForge also exists to promote best-practice software development methods and to provide a central repository for re-usable HEP software and phenomenology codes.

A. Buckley; J. M. Butterworth; E. Nurse; W. J. Stirling; B. Waugh; M. R. Whalley

2006-05-04

172

Forging limits for an aluminum matrix composite: Part II. Analysis  

NASA Astrophysics Data System (ADS)

Plasticity analysis has been carried out to calculate the forging limits of a particulate-reinforced aluminum matrix composite under various forging conditions. A geometric defect (i.e., variation in cross-sectional area) that can concentrate stresses and strain and accelerate local deformation was assumed to represent all possible defects in this material. Thus, in effect, the local stress concentrations around nondeformable particles, inhomogeneous distribution of particles and grain sizes, porosity and cracked particles, etc., were assumed to be simulated adequately by such a defect factor. The analysis followed a method suggested by Marciniak and Kuczynski (MK) to determine the strain path within the defect region of the composite during multiaxial deformation. A relationship of stress, strain, and strain rate obtained from the uniaxial tension test was used for the calculation of the strains. To terminate the plasticity analysis, a rateindependent fracture criterion was used that is based on Cockcroft’s model of a constant work performed by the tensile component of stress. It was found that the calculated results predicted the experimental forging limits for 2014 Al/15 vol pct A12O3 reasonably well. At 400 °C and a slow strain rate (0.015 s~’), the predicted curve was higher than the experimental result. This was probably because the fracture mechanism, and thus fracture criterion, changed with temperature. The effect of assumed defect factor on predicted forging limits was also studied. It was found that the size of the defect factor did not significantly change the forging limits at 300 °C for strain rates from 0.015 s to 0.5 s-1; however, it did have a large effect on the forging limit at 400 °C for the lower strain rate of 0.015 s-1.

Syu, D.-G. C.; Ghosh, A. K.

1994-09-01

173

48 CFR 252.225-7025 - Restriction on acquisition of forgings.  

Code of Federal Regulations, 2010 CFR

...225-7025 Restriction on acquisition of forgings. As prescribed...clause: Restriction on Acquisition of Forgings (DEC 2009...subsection 225.7102-3 of the Defense Federal Acquisition Regulation Supplement. (d) The...

2010-10-01

174

Relationships Between Process Parameters, Microstructure, and Adhesion Strength of HVOF Sprayed IN718 Coatings  

NASA Astrophysics Data System (ADS)

Fundamental understanding of relationships between process parameters, particle in-flight characteristics, and adhesion strength of HVOF sprayed coatings is important to achieve the high coating adhesion that is needed in aeronautic repair applications. In this study, statistical Design of Experiments (DoE) was used to identify the most important process parameters that influence adhesion strength of IN718 coatings sprayed on IN718 substrates. Special attention was given to the parameters combustion ratio, total gas mass flow, stand-off distance and external cooling, since these parameters were assumed to have a significant influence on particle temperature and velocity. Relationships between these parameters and coating microstructure were evaluated to fundamentally understand the relationships between process parameters and adhesion strength.

Lyphout, Christophe; Nylén, Per; Östergren, Lars

2011-01-01

175

An Advanced User Interface Approach for Complex Parameter Study Process Specification in the Information Power Grid  

NASA Technical Reports Server (NTRS)

The creation of parameter study suites has recently become a more challenging problem as the parameter studies have now become multi-tiered and the computational environment has become a supercomputer grid. The parameter spaces are vast, the individual problem sizes are getting larger, and researchers are now seeking to combine several successive stages of parameterization and computation. Simultaneously, grid-based computing offers great resource opportunity but at the expense of great difficulty of use. We present an approach to this problem which stresses intuitive visual design tools for parameter study creation and complex process specification, and also offers programming-free access to grid-based supercomputer resources and process automation.

Yarrow, Maurice; McCann, Karen M.; Biswas, Rupak; VanderWijngaart, Rob; Yan, Jerry C. (Technical Monitor)

2000-01-01

176

FATIGUE PERFORMANCE COMPARISON AND LIFE PREDICTION OF FORGED STEEL AND DUCTILE CAST IRON CRANKSHAFTS  

E-print Network

1 FATIGUE PERFORMANCE COMPARISON AND LIFE PREDICTION OF FORGED STEEL AND DUCTILE CAST IRON. The crankshafts used in the study were forged steel and ductile cast iron from a one-cylinder gasoline engine fatigue strength than the ductile cast iron, while component tests showed that the forged steel crankshaft

Fatemi, Ali

177

76 FR 30200 - Forging Machines; Extension of the Office of Management and Budget's (OMB) Approval of...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Docket No. OSHA-2011-0064] Forging Machines; Extension of the Office of Management...requirements contained in the Forging Machines Standard (29 CFR 1910.218). The...serious injury by ensuring that forging machines used by them are in safe operating...

2011-05-24

178

Proceedings of Student Research Day, CSIS, Pace University, May 9th, 2003 Forged Handwriting Detection  

E-print Network

Proceedings of Student Research Day, CSIS, Pace University, May 9th, 2003 Forged Handwriting of the writer, but handwriting experts are often required to differentiate between authentic and forged signatures. For this reason it is important to build an objective system to identify forged handwriting

Tappert, Charles

179

Some features on hot forging of powder metallurgy sintered high strength 4%titanium carbide composite steel preforms under different stress state conditions  

Microsoft Academic Search

In this paper, the authors propose mathematical expressions for the determination of different stress ratio parameters under plane and triaxial stress state conditions. Experiments were carried out to evaluate the hot forging features in the high strength sintered powder metallurgy 4%titanium carbide composite steel performs under different stress states, namely, plane stress and triaxial stress states. Cylindrical compacts with aspect

R. Narayanasamy; V. Senthilkumar; K. S. Pandey

2008-01-01

180

Effects of Processing Parameters on the Forming Quality of C-Shaped Thermosetting Composite Laminates in Hot Diaphragm Forming Process  

NASA Astrophysics Data System (ADS)

In this study, the effects of processing temperature and vacuum applying rate on the forming quality of C-shaped carbon fiber reinforced epoxy resin matrix composite laminates during hot diaphragm forming process were investigated. C-shaped prepreg preforms were produced using a home-made hot diaphragm forming equipment. The thickness variations of the preforms and the manufacturing defects after diaphragm forming process, including fiber wrinkling and voids, were evaluated to understand the forming mechanism. Furthermore, both interlaminar slipping friction and compaction behavior of the prepreg stacks were experimentally analyzed for showing the importance of the processing parameters. In addition, autoclave processing was used to cure the C-shaped preforms to investigate the changes of the defects before and after cure process. The results show that the C-shaped prepreg preforms with good forming quality can be achieved through increasing processing temperature and reducing vacuum applying rate, which obviously promote prepreg interlaminar slipping process. The process temperature and forming rate in hot diaphragm forming process strongly influence prepreg interply frictional force, and the maximum interlaminar frictional force can be taken as a key parameter for processing parameter optimization. Autoclave process is effective in eliminating voids in the preforms and can alleviate fiber wrinkles to a certain extent.

Bian, X. X.; Gu, Y. Z.; Sun, J.; Li, M.; Liu, W. P.; Zhang, Z. G.

2013-10-01

181

Optimization and Simulation of Machining Parameters in Radial-axial Ring Rolling Process  

Microsoft Academic Search

Ring rolling is a complicated process, in which rolling parameters influence directly the quality of ring. It is a process method with high productivity and few waste of material, widely used in transportation industry including automotive, shipbuilding, aerospace etc. During the rolling process of large-sized parts, crinkle and hollows often appear on surface, due to inconsistence of rolling motions with

Shuiyuan Tang; Jiping Lu; Hongli Fan; Ruizhao Du; Zhonghua Jiang; Ning Ma

2011-01-01

182

Probabilistic parameter estimation of activated sludge processes using Markov Chain Monte Carlo.  

PubMed

One of the most important challenges in making activated sludge models (ASMs) applicable to design problems is identifying the values of its many stoichiometric and kinetic parameters. When wastewater characteristics data from full-scale biological treatment systems are used for parameter estimation, several sources of uncertainty, including uncertainty in measured data, external forcing (e.g. influent characteristics), and model structural errors influence the value of the estimated parameters. This paper presents a Bayesian hierarchical modeling framework for the probabilistic estimation of activated sludge process parameters. The method provides the joint probability density functions (JPDFs) of stoichiometric and kinetic parameters by updating prior information regarding the parameters obtained from expert knowledge and literature. The method also provides the posterior correlations between the parameters, as well as a measure of sensitivity of the different constituents with respect to the parameters. This information can be used to design experiments to provide higher information content regarding certain parameters. The method is illustrated using the ASM1 model to describe synthetically generated data from a hypothetical biological treatment system. The results indicate that data from full-scale systems can narrow down the ranges of some parameters substantially whereas the amount of information they provide regarding other parameters is small, due to either large correlations between some of the parameters or a lack of sensitivity with respect to the parameters. PMID:24384542

Sharifi, Soroosh; Murthy, Sudhir; Takács, Imre; Massoudieh, Arash

2014-03-01

183

A review of pharmaceutical extrusion: critical process parameters and scaling-up.  

PubMed

Hot melt extrusion has been a widely used process in the pharmaceutical area for three decades. In this field, it is important to optimize the formulation in order to meet specific requirements. However, the process parameters of the extruder should be as much investigated as the formulation since they have a major impact on the final product characteristics. Moreover, a design space should be defined in order to obtain the expected product within the defined limits. This gives some freedom to operate as long as the processing parameters stay within the limits of the design space. Those limits can be investigated by varying randomly the process parameters but it is recommended to use design of experiments. An examination of the literature is reported in this review to summarize the impact of the variation of the process parameters on the final product properties. Indeed, the homogeneity of the mixing, the state of the drug (crystalline or amorphous), the dissolution rate, the residence time, can be influenced by variations in the process parameters. In particular, the impact of the following process parameters: temperature, screw design, screw speed and feeding, on the final product, has been reviewed. PMID:25541517

Thiry, J; Krier, F; Evrard, B

2015-02-01

184

Statistical analysis of process parameters in drilling of AL\\/SIC P metal matrix composite  

Microsoft Academic Search

This paper presents a statistical analysis of process parameters for surface roughness in drilling of Al\\/SiCp metal matrix\\u000a composite. The experimental studies were conducted under varying spindle speed, feed rate, drill type, point angle of drill,\\u000a and heat treatment. The settings of drilling parameters were determined by using Taguchi experimental design method. The level\\u000a of importance of the drilling parameters

Gül Tosun

2011-01-01

185

Forging Consensus for Implementing Youth Socialization Policy in Northwest China  

ERIC Educational Resources Information Center

The goal of this article is to examine how the provincial education media in China play a role of forging consensus among local actors responsible for the implementation of new centrally-promulgated youth socialization policy. In doing so, it also explores the tension among three of the Chinese state's claims to legitimacy: economic development,…

Fairbrother, Gregory P.

2011-01-01

186

Effect of Combustion Air Preheat on a Forged Furnace Productivity  

E-print Network

A basic thermal analysis of a gas fired forge furnace can determine the fuel savings from exhaust energy recovery/combustion air preheat on a furnace operating at a single condition, for example, high fire. What this analysis is not able...

Ward, M. E.; Bohn, J.; Davis, S. R.; Knowles, D.

1984-01-01

187

Family Health and Financial Literacy--Forging the Connection  

ERIC Educational Resources Information Center

Families are at-risk of or experiencing a diminished quality of living and life in current economic times and difficult decisions are required. Health and financial literacy are the basis for wise personal and public decision making. Family and consumer sciences (FCS) professionals can forge connections between health and financial literacy to…

Braun, Bonnie; Kim, Jinhee; Anderson, Elaine A.

2009-01-01

188

Electronic Portfolios in Teacher Education: Forging a Middle Ground  

ERIC Educational Resources Information Center

At a time when implementation of electronic portfolios (EPs) is expanding, the issues of clarifying their purposes continue to plague teacher education programs. Are student-centered uses of EPs compatible with program assessment and accreditation efforts? Is this an either/or situation, or can a productive middle ground be forged? This article…

Strudler, Neal; Wetzel, Keith

2012-01-01

189

The Valley Forge Encampment: Epic on the Schuylkill.  

ERIC Educational Resources Information Center

Valley Forge, outside Philadelphia (Pennsylvania), has long been recognized as the site of a great victory of the human spirit. Eleven thousand men including Blacks and Indians resided there during the winter of 1777-78 and triumphed over cold, starvation, nakedness, disease, and uncertainty. The encampment site was unprepared for the tattered,…

Trussell, John B. B., Jr.

190

Control of carbon nanotube stiffness via tunable fabrication process parameters that determine CNT geometry  

E-print Network

This paper presents tunable process parameters that may be used to control the geometry of multi-walled carbon nanotubes (MWCNTs). The results may be used to grow MWCNTs with desired stiffness properties. This is important ...

Cullinan, Michael A. (Michael Arthur)

2008-01-01

191

Bayesian wavelet approaches for parameter estimation and change point detection in long memory processes  

E-print Network

the exact variance-covariance matrix of given ARFIMA(p, d, q) process and transforming them into wavelet domains using two dimensional discrete wavelet transform (DWT2). Metropolis algorithm is used for sampling the model parameters from the posterior...

Ko, Kyungduk

2005-11-01

192

The effect of milling parameters on starch hydrolysis of milled malt in the brewing process  

Microsoft Academic Search

The effect of milling parameters on the hydrolysis of starch during the mashing process was investigated. Hammer milling was compared against roll milling. Roll gap settings, roll speed, speed differential were also analysed, as well as comparing four- to six-roll milling. The parameter of differential speed was also studied through grist particle size distribution. Employing a 65°C infusion type mashing

Z. Mousia; R. C. Balkin; S. S. Pandiella; C. Webb

2004-01-01

193

Plant parameters for plant functional groups of western rangelands to enable process-based simulation modeling  

Technology Transfer Automated Retrieval System (TEKTRAN)

Regional environmental assessments with process-based models require realistic estimates of plant parameters for the primary plant functional groups in the region. “Functional group” in this context is an operational term, based on similarities in plant type and in plant parameter values. Likewise...

194

Optimization of image process parameters through factorial experiments using a flat panel detector  

NASA Astrophysics Data System (ADS)

In the optimization process of lumbar spine examinations, factorial experiments were performed addressing the question of whether the effective dose can be reduced and the image quality maintained by adjusting the image processing parameters. A 2k-factorial design was used which is a systematic and effective method of investigating the influence of many parameters on a result variable. Radiographic images of a Contrast Detail phantom were exposed using the default settings of the process parameters for lumbar spine examinations. The image was processed using different settings of the process parameters. The parameters studied were ROI density, gamma, detail contrast enhancement (DCE), noise compensation, unsharp masking and unsharp masking kernel (UMK). The images were computer analysed and an image quality figure (IQF) was calculated and used as a measurement of the image quality. The parameters with the largest influence on image quality were noise compensation, unsharp masking, unsharp masking kernel and detail contrast enhancement. There was an interaction between unsharp masking and kernel indicating that increasing the unsharp masking improved the image quality when combined with a large kernel size. Combined with a small kernel size however the unsharp masking had a deteriorating effect. Performing a factorial experiment gave an overview of how the image quality was influenced by image processing. By adjusting the level of noise compensation, unsharp masking and kernel, the IQF was improved to a 30% lower effective dose.

Norrman, Eva; Geijer, Håkan; Persliden, Jan

2007-09-01

195

Roles of the influential parameters in the incineration process using centrality concept of graph theory  

NASA Astrophysics Data System (ADS)

The dioxin furan is byproducts of the incineration process in which becomes a major concern to the public. In this paper, the role of the influential parameters affecting the Dioxin Furan Emission (DFE) in the incineration process was discussed. A total of seven selected incinerators in Malaysia were considered in the study. The incineration plant was categorized into the type of waste incinerated during the process, i.e. sludge and biomedical waste. Six parameters comprise of temperature, nitrogen oxide, sulphur dioxide, carbon dioxide, oxygen and moisture content were identified as the influential parameters affecting the DFE of the incineration process. Multiple Linear Regression (MLR) models were initially developed to relate the DFE and the influential parameters in each category of incinerators. These models served as the basis for the construction of the graphical models representing the interaction of the influential parameters in the process. Centrality concept was then used on these graphical models to describe the role of the parameters in the process.

Awatif, W. A.; Sabariah, B.; Rashid, M.; Normah, M.

2014-06-01

196

Optimization of a Cu CMP process modeling parameters of nanometer integrated circuits  

NASA Astrophysics Data System (ADS)

A copper chemical mechanical polishing (Cu CMP) process is reviewed and analyzed from the view of chemical physics. Three steps Cu CMP process modeling is set up based on the actual process of manufacturing and pattern-density-step-height (PDSH) modeling from MIT. To catch the pattern dependency, a 65 nm testing chip is designed and processed in the foundry. Following the model parameter extraction procedure, the model parameters are extracted and verified by testing data from the 65 nm testing chip. A comparison of results between the model predictions and test data show that the former has the same trend as the latter and the largest deviation is less than 5 nm. Third party testing data gives further evidence to support the great performance of model parameter optimization. Since precise CMP process modeling is used for the design of manufacturability (DFM) checks, critical hotspots are displayed and eliminated, which will assure good yield and production capacity of IC.

Wenbiao, Ruan; Lan, Chen; Tianyu, Ma; Jingjing, Fang; He, Zhang; Tianchun, Ye

2012-08-01

197

Effect of spray drying processing parameters on the insecticidal activity of two encapsulated formulations of baculovirus  

Technology Transfer Automated Retrieval System (TEKTRAN)

The aim of this work was to evaluate the effect of spray dryer processing parameters on the process yield and insecticidal activity of baculovirus to support the development of this beneficial group of microbes as biopesticides. For each of two baculoviruses [granulovirus (GV) from Pieris rapae (L....

198

Fixed-point based autoregressive parameter estimation for space time adaptive processing  

Microsoft Academic Search

Space time adaptive processing (STAP) is useful in radar processing to detect a target by filtering the clutter and the additive thermal noise. A derived version based on a multichannel autoregressive (M-AR) model of the clutter has the advantage of reducing the computational cost. Nevertheless, the estimation of the AR matrix parameters is a key issue because the clutter is

Julien Petitjean; Eric Grivel; Patrick Roussilhe

2010-01-01

199

The kinetic parameters and safe operating conditions of nitroglycerine manufacture in the CSTR of Biazzi process  

Microsoft Academic Search

Nitroglycerine has been widely used as an ingredient of explosives and propellants for a long time. It is produced by the glycerine nitration reaction. Many fire and explosion incidents have occurred during its manufacturing process owing to its severe thermal instability in both the nitration reaction and the purification processes. The kinetic parameters of this reaction and the criteria for

Kai-Tai Lu; Kuo-Ming Luo; Tsao-Fa Yeh; Peng-Chu Lin

2008-01-01

200

Online distributed state and parameter estimation for feedback control of a curing process  

Microsoft Academic Search

Radiation-based processes can help realize environmentally sound alternative approaches for curing coating materials. To ensure quality of cure with feedback control, the determination of target cure status remains a difficult challenge, particularly when the radiant source needs to move in space for automating the process. In this paper, the problem is cast as a distributed nonlinear state and parameter estimation

Fan Zeng; Beshah Ayalew

2010-01-01

201

Multi-Response Optimization of Process Parameters for Low-Pressure Cold Spray Coating Process Using Taguchi and Utility Concept  

NASA Astrophysics Data System (ADS)

Most of the existing multi-response optimization approaches focus on the subjective and practical know-how of the process. As a result, some confusion and uncertainty are introduced in the overall decision-making process. In this work, an approach based on a Utility theory and Taguchi quality loss function has been applied to the process parameters for low-pressure cold spray process deposition of copper coatings, for simultaneous optimization of more than one response characteristics. In the present paper, two potential response parameters, i.e., coating thickness and coating density, have been selected. Utility values based on these response parameters have been analyzed for optimization using the Taguchi approach. The selected input parameters of powder feeding arrangement, substrate material, air stagnation pressure, air stagnation temperature, and stand-off distance significantly improve the Utility function (raw data) comprising quality characteristics (coating thickness and coating density). The percentage contribution of the parameters to achieve a higher value of Utility function is substrate material (50.03%), stand-off distance (28.87%), air stagnation pressure (6.41%), powder feeding arrangement (4.68%), and air stagnation temperature (2.64%).

Goyal, Tarun; Sidhu, T. S.; Walia, R. S.

2014-01-01

202

Effects of the Deslagging Process on some Physicochemical Parameters of Honey  

PubMed Central

Some physicochemical parameters of honey have been introduced by the International Honey Commission to evaluate its quality and origin but processes such as heating and filtering can affect these parameters. In traditional Iranian medicine, deslagging process involves boiling honey in an equal volume of water and removing the slag formed during process. The aim of this study was to determine the effects of deslagging process on parameters of color intensity, diastase evaluation, electrical conductivity, pH, free acidity, refractive index, hydroxy methyl furfural (HMF), proline and water contents according to the International Honey Committee (IHC) standards. The results showed that deslagged honey was significantly different from control honey in terms of color intensity, pH, diastase number, HMF and proline content. It can be concluded that the new standards are needed to regulate deslagged honey.

Ranjbar, Ali Mohammad; Sadeghpour, Omid; Khanavi, Mahnaz; Shams Ardekani, Mohammad Reza; Moloudian, Hamid; Hajimahmoodi, Mannan

2015-01-01

203

Investigation of effective parameters on surface roughness in thermomechanical tube spinning process  

Microsoft Academic Search

Tube spinning process is recognized as an effective process for fabricating of thin wall cylindrical parts, with precision\\u000a tolerances, high surface quality and desired mechanical property. In this research, the influences of major parameters of\\u000a thermomechanical tube spinning process such as preform thickness, percentage of thickness reduction, mandrel rotational speed,\\u000a feed rate of rollers, solution treatment time and aging treatment

A. R. Fazeli; Majid Ghoreishi

2009-01-01

204

Correlation of Process Parameters and Part Properties in Laser Sintering using Response Surface Modeling  

NASA Astrophysics Data System (ADS)

Due to the advancements during the last decade, the laser sintering process has achieved a high technical level, allowing for Rapid Manufacturing in some applications. However, processes still show poor repeatability of part quality, process interruptions or defective parts. The knowledge needed to avoid such problems is still insufficient. Literature provides only few detailed correlations between process parameters and part properties. Therefore, an approach using response surface methodology was chosen to correlate part properties with main influencing factors. Aim of the analyses was to predict and to improve part properties based on an enhanced process understanding.

Wegner, Andreas; Witt, Gerd

205

COUPLING CONSTRAINT BOUNDARY MAPPING IN THE PROCESS DESIGN PARAMETER SPACE WITH COMMERCIAL PROCESS SIMULATOR TO ESTIMATE PROCESS DESIGN RELIABILITY  

E-print Network

of BP’s estimated for the second geometrical case study……………………………………….. 59 Figure 3.5 CB in parameter space for third geometrical case……………………. 60 Figure 3.6 CB in parameter space for fourth geometrical case study……………. 60 Figure 3.7 M/I design....6 OPT PDR estimates for the case studies with two uncertain parameters when %1=OP? …………………………………………… 42 Table 2.7 OPT PDR estimates for designs with more than two uncertain parameters when fifty BP’s are used in the CBA…………………….. 42 Table 2...

Myers, Elim Rosalva

2010-01-25

206

Influence of several experimental parameters on inter and intra specific mating process efficiency.  

PubMed

In this study we investigated the influence that several experimental parameters may product on the mating process efficiency. We used the ordinary mating technique described by other authors and we examined the effect of temperature, media and plasmid size on the number of recipient cells transformed by mating procedure. The results showed that the most important parameter influencing the efficiency of the mating transformation is the media, associated with the size of the plasmid to be transferred. PMID:2555654

Sambri, V; Lovett, M A

1989-10-01

207

Effects of layer thickness and binder saturation level parameters on 3D printing process  

Microsoft Academic Search

Various parameters, such as binder properties, printing layer thickness, powder size, and binder saturation level, have effects\\u000a on the strength and surface finish of the three-dimensional printing (3D printing) process. The objective of this research\\u000a is to study the effects of two parameters of layer thickness and binder saturation level on mechanical strength, integrity,\\u000a surface quality, and dimensional accuracy in

Mohammad Vaezi; Chee Kai Chua

2011-01-01

208

Effects of electrolyte parameters on the iron\\/steel cathode potential in the chlorate process  

Microsoft Academic Search

This study focuses on how different electrolyte parameters of the chlorate process affect the cathode potential for hydrogen\\u000a evolution on iron in a wide current-density range. The varied parameters were pH, temperature, mass transport conditions and\\u000a the ionic concentrations of chloride, chlorate, chromate and hypochlorite. At lower current densities, where cathodic protection\\u000a of the electrode material is important, the pH

Linda Nylén; Ann Cornell

2009-01-01

209

Crack toughness evaluation of hot pressed and forged beryllium.  

NASA Technical Reports Server (NTRS)

Fracture toughness tests at room temperature were made on three-point loaded beryllium bend specimens cut from hot pressed block and a forged disk. These specimens had plane proportions conforming to ASTM E 399 and covered a thickness range of from 1/32 to 1/2 in. Two sets of bend specimens were tested, one having fatigue cracks and the other 0.5 mil radius notches. One objective of the investigation was the development of techniques to produce fatigue cracks in accordance with the procedures specified in ASTM E 399. This objective was achieved for the hot pressed material. In plane cracks were not consistently produced in the specimens cut from forged stock.

Jones, M. H.; Bubsey, R. T.; Brown, W. F., Jr.

1973-01-01

210

Mammalian cell culture process for monoclonal antibody production: nonlinear modelling and parameter estimation.  

PubMed

Monoclonal antibodies (mAbs) are at present one of the fastest growing products of pharmaceutical industry, with widespread applications in biochemistry, biology, and medicine. The operation of mAbs production processes is predominantly based on empirical knowledge, the improvements being achieved by using trial-and-error experiments and precedent practices. The nonlinearity of these processes and the absence of suitable instrumentation require an enhanced modelling effort and modern kinetic parameter estimation strategies. The present work is dedicated to nonlinear dynamic modelling and parameter estimation for a mammalian cell culture process used for mAb production. By using a dynamical model of such kind of processes, an optimization-based technique for estimation of kinetic parameters in the model of mammalian cell culture process is developed. The estimation is achieved as a result of minimizing an error function by a particle swarm optimization (PSO) algorithm. The proposed estimation approach is analyzed in this work by using a particular model of mammalian cell culture, as a case study, but is generic for this class of bioprocesses. The presented case study shows that the proposed parameter estimation technique provides a more accurate simulation of the experimentally observed process behaviour than reported in previous studies. PMID:25685797

Seli?teanu, Dan; ?endrescu, Dorin; Georgeanu, Vlad; Roman, Monica

2015-01-01

211

Mammalian Cell Culture Process for Monoclonal Antibody Production: Nonlinear Modelling and Parameter Estimation  

PubMed Central

Monoclonal antibodies (mAbs) are at present one of the fastest growing products of pharmaceutical industry, with widespread applications in biochemistry, biology, and medicine. The operation of mAbs production processes is predominantly based on empirical knowledge, the improvements being achieved by using trial-and-error experiments and precedent practices. The nonlinearity of these processes and the absence of suitable instrumentation require an enhanced modelling effort and modern kinetic parameter estimation strategies. The present work is dedicated to nonlinear dynamic modelling and parameter estimation for a mammalian cell culture process used for mAb production. By using a dynamical model of such kind of processes, an optimization-based technique for estimation of kinetic parameters in the model of mammalian cell culture process is developed. The estimation is achieved as a result of minimizing an error function by a particle swarm optimization (PSO) algorithm. The proposed estimation approach is analyzed in this work by using a particular model of mammalian cell culture, as a case study, but is generic for this class of bioprocesses. The presented case study shows that the proposed parameter estimation technique provides a more accurate simulation of the experimentally observed process behaviour than reported in previous studies. PMID:25685797

Seli?teanu, Dan; ?endrescu, Dorin; Georgeanu, Vlad

2015-01-01

212

TECHNICAL NOTE: Adhesive bonding of microfluidic chips: influence of process parameters  

NASA Astrophysics Data System (ADS)

In this note, the influence of process parameters for adhesive bonding as a versatile approach for the sealing of polymer microfluidic chips is investigated. Specifically, a process chain comprising pre-processing, adhesive transfer as well as post-processing is presented and parameter recommendations are provided. As a device for adhesive transfer, a modified laminator is utilized which transfers thin layers of adhesive onto the chip surface, only via a silicone roll. Using this device and a high temperature (Tg > 100 °C) epoxy adhesive, adhesive layers in the range of 2-4 µm can be reproducibly transferred (CV < 4%). For best bonding results, it is recommended to provide 2.5 µm thin layers of adhesive in combination with a subsequent evacuation step at 10 mbar for 3 h. Further, it is proposed to integrate capture channels near large, featureless areas to compensate for variations in processing and thus prevent clogging of channels.

Riegger, Lutz; Strohmeier, Oliver; Faltin, Bernd; Zengerle, Roland; Koltay, Peter

2010-08-01

213

Influence of different plasma nitriding treatments on the wear and crack behavior of forging tools evaluated by Rockwell indentation and scratch tests  

Microsoft Academic Search

Forging tools are often showing short lifetimes compared to cold forming tools e.g. for sheet metal forming. This is based on the process conditions where high local surface temperatures are alternating with chilling conditions due to the spray cooling with water based cooling lubricants. The resulting thermal shock is provoking fatigue of the tool material in the near surface regions.

H. Paschke; M. Weber; P. Kaestner; G. Braeuer

2010-01-01

214

Statistical analysis of process parameters to eliminate hot cracking of fiber laser welded aluminum alloy  

NASA Astrophysics Data System (ADS)

This paper investigates hot cracking rate in Al fiber laser welding under various process conditions and performs corresponding process optimization. First, effects of welding process parameters such as distance between welding center line and its closest trim edge, laser power and welding speed on hot cracking rate were investigated experimentally with response surface methodology (RSM). The hot cracking rate in the paper is defined as ratio of hot cracking length over the total weld seam length. Based on the experimental results following Box-Behnken design, a prediction model for the hot cracking rate was developed using a second order polynomial function considering only two factor interaction. The initial prediction result indicated that the established model could predict the hot cracking rate adequately within the range of welding parameters being used. The model was then used to optimize welding parameters to achieve cracking-free welds.

Wang, Jin; Wang, Hui-Ping; Wang, Xiaojie; Cui, Haichao; Lu, Fenggui

2015-03-01

215

Design of experiment (DOE) method considering interaction effect of process parameters for optimization of copper chemical mechanical polishing (CMP) process  

Microsoft Academic Search

Chemical mechanical polishing (CMP) has been widely accepted for the metallization of copper interconnection in ultra-large scale integrated circuits (ULSIs) manufacturing. It is important to understand the effect of the process variables such as turntable speed, head speed, down force and back pressure on copper CMP. They are very important parameters that must be carefully formulated to achieve desired the

Nam-Hoon Kim; Min-Ho Choi; Sang-Yong Kim; Eui-Goo Chang

2006-01-01

216

Hot forging of a nickel-base superalloy  

Microsoft Academic Search

Compression tests were carried out to investigate the hot-deformation behavior of nickel-based Alloy 718. The tests were conducted in the temperature range 982–1066°C and the strain rate range 5×10?4–5.0s?1. Pancakes were also made by multi-step forging and their microstructures were compared with specimen-base compression tests.Hot-deformation behavior was led mainly by dynamic recrystallization as well as by dynamic recovery. Dynamic recrystallization

N. K. Park; I. S. Kim; Y. S. Na; J. T. Yeom

2001-01-01

217

Structural variations in heat treated low alloy steel forgings  

Microsoft Academic Search

A study has been made of the microstructures of two low alloy Cr–Mo–Ni–V steel forgings in the quenched and tempered condition. Optical metallography of variously etched specimens, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and X-ray diffraction were used to characterize the tempered martensite microstructures. Variations in prior austenite grain size and martensite lath structure have been related

S Maropoulos; N Ridley; S Karagiannis

2004-01-01

218

Effects of Process Parameters on Replication Accuracy of Microinjection Molded Cyclic Olefins Copolymers Parts  

NASA Astrophysics Data System (ADS)

In this study, the effects of various processing parameters of microinjection molding on the replication accuracy of the micro featured fluidic platform used for DNA/RNA tests are investigated. LIGA-like processes were utilized to prepare a silicon-based SU-8 photoresist, followed by electroforming to make a Ni-Co-based stamp. A cyclic olefin copolymer (COC) was used as the injection molding material. The molding parameters associated with the replication accuracy of micro channel parts were investigated. It was found that for microinjection molded devices, the replication accuracies of the imprint width and depth increase with increasing of mold temperature, melt temperature, injection velocity, and packing pressure.

Lin, Hsuan-Liang; Chen, Chun-Sheng; Lee, Ruey-Tsung; Chen, Shia-Chung; Chien, Rean-Der; Jeng, Ming-Chang; Hwang, Jiun-Ren

2013-04-01

219

Parameter estimation by fixed point of function of information processing intensity  

NASA Astrophysics Data System (ADS)

We present a new method of estimating the dispersion of a distribution which is based on the surprising property of a function that measures information processing intensity. It turns out that this function has a maximum at its fixed point. Fixed-point equation is used to estimate the parameter of the distribution that is of interest to us. The main result consists in showing that only part of available experimental data is relevant for the parameters estimation process. We illustrate the estimation method by using the example of an exponential distribution.

Jankowski, Robert; Makowski, Marcin; Piotrowski, Edward W.

2014-12-01

220

Effect of Process Parameters on Abnormal Grain Growth during Friction Stir Processing of a Cast Al Alloy  

SciTech Connect

The effects of process parameters and friction stir processing (FSP) run configurations on the stability of nugget microstructure at elevated temperatures were evaluated. Cast plates of an Al-7Si- 0.6Mg alloy were friction stir processed using a combination of tool rotation rates and tool traverse speeds. All single pass runs showed some extent of abnormal grain growth (AGG), whereas multi-pass runs were more resistant to AGG. Additionally, higher tool rpm was found to be beneficial for controlling AGG. These effects were analyzed by comparing the result of this work with other published results and AGG models.

Jana, Saumyadeep; Mishra, Rajiv S.; Baumann, John A.; Grant, Glenn J.

2010-11-25

221

Influence of Processing Parameters on the Flow Path in Friction Stir Welding  

NASA Technical Reports Server (NTRS)

Friction stir welding (FSW) is a solid phase welding process that unites thermal and mechanical aspects to produce a high quality joint. The process variables are rpm, translational weld speed, and downward plunge force. The strain-temperature history of a metal element at each point on the cross-section of the weld is determined by the individual flow path taken by the particular filament of metal flowing around the tool as influenced by the process variables. The resulting properties of the weld are determined by the strain-temperature history. Thus to control FSW properties, improved understanding of the processing parameters on the metal flow path is necessary.

Schneider, J. A.; Nunes, A. C., Jr.

2006-01-01

222

Optimization of LPDC Process Parameters Using the Combination of Artificial Neural Network and Genetic Algorithm Method  

NASA Astrophysics Data System (ADS)

In this article, the low-pressure die-cast (LPDC) process parameters of aluminum alloy thin-walled component with permanent mold are optimized using a combining artificial neural network and genetic algorithm (ANN/GA) method. In this method, an ANN model combining learning vector quantization (LVQ) and back-propagation (BP) algorithm is proposed to map the complex relationship between process conditions and quality indexes of LPDC. The genetic algorithm is employed to optimize the process parameters with the fitness function based on the trained ANN model. Then, by applying the optimized parameters, a thin-walled component with 300 mm in length, 100 mm in width, and 1.5 mm in thickness is successfully prepared and no obvious defects such as shrinkage, gas porosity, distortion, and crack were found in the component. The results indicate that the combining ANN/GA method is an effective tool for the process optimization of LPDC, and they also provide valuable reference on choosing the right process parameters for LPDC thin-walled aluminum alloy casting.

Zhang, Liqiang; Li, Luoxing; Wang, Shiuping; Zhu, Biwu

2012-04-01

223

The effects of process parameters on injection-molded PZT ceramics part fabrication- compounding process rheology.  

SciTech Connect

Solid solutions of lead-based perovskites are the backbone materials of the piezoelectric components for transducer, actuator, and resonator applications. These components, typically small in size, are fabricated from large sintered ceramic slugs using grinding and lapping processes. These operations increase manufacturing costs and produce a large hazardous waste stream, especially when component size decreases. To reduce costs and hazardous wastes associated with the production of these components, an injection molding technique is being investigated to replace the machining processes. The first step in the new technique is to compound an organic carrier with a ceramic powder. The organic carrier is a thermoplastic based system composed of a main carrier, a binder, and a surfactant. Understanding the rheology of the compounded material is necessary to minimize the creation of defects such as voids or cavities during the injection-molding process. An experiment was performed to model the effects of changes in the composition and processing of the material on the rheological behavior. Factors studied included: the surfactant of the organic carrier system, the solid loading of the compounded material, and compounding time. The effects of these factors on the viscosity of the material were investigated.

Halbleib, Laura L.; Yang, Pin; Mondy, Lisa Ann; Burns, George Robert

2005-05-01

224

Effect of laser processing parameters on the structure of ductile iron  

Microsoft Academic Search

Laser processing of structure sensitive hypereutectic ductile iron, a cast alloy employed for dynamically loaded automative components, was experimentally investigated over a wide range of process parameters: from power (0.5–2.5 kW) and scan rate (7.5–25 mm s?1) leading to solid state transformation, all the way through to melting followed by rapid quenching. Superfine dendritic (at 105 °C s?1) or feathery

S. P. Gadag; M. N. Srinivasan; B. L. Mordike

1995-01-01

225

Parameter comparison of two small-scale natural gas liquefaction processes in skid-mounted packages  

Microsoft Academic Search

Two typical types of small-scale natural gas liquefaction process in skid-mounted package were designed and simulated. The key parameters of the two processes were compared, and the matching of the heating and cooling curves in heat exchangers was also analyzed. The results show that the N2–CH4 expander cycle precedes the mixed-refrigerant cycle on the premise of lacking propane pre-cooling. Large

Wen-sheng Cao; Xue-sheng Lu; Wen-sheng Lin; An-zhong Gu

2006-01-01

226

A novel forged image detection method using the characteristics of interpolation.  

PubMed

Development of digital image-editing programs has enabled us to be widely exposed to forged digital images surrounding us. Such forged images have been dispersed through the Internet, newspaper articles, and magazines, and in particular, the information contained in these unverified images happened to be regarded as true. As a result, the forged images provided wrong information for individuals and society, thus sometimes creating social issues. In order to solve such problems, this study was aimed to suggest the methods of identifying the veracity of forged images. In this way, it suggested re-interpolation algorithm. Namely, the study re-interpolated in identical arbitrary values both the interpolated and un-interpolated regions based on the interpolation used a lot in forged, confirmed discrete fourier transform (DFT) characteristics of these two regions, and embodied a detection map for the final forged images, using the subtraction value between two regions in DFT characteristics. PMID:22931351

Hwang, Min-Gu; Har, Dong-Hwan

2013-01-01

227

Direct extrusion process analysis with proposed numerical modeling improvements - product quality, process parameters, and microstructure prediction  

Microsoft Academic Search

A numerical modeling and simulation analysis was performed on the hot-direct extrusion process with the finite element modeling (FEM) software package, DEFORM(TM) 3-D for three case studies. The research demonstrated that a commercially available, industry-accepted numerical simulation software package can predict the material response and microstructure development with simple simulated state variables (i.e. strain, strain rate, and temperature) and easily

Luigi de Pari Jr.

2009-01-01

228

Multiobjective optimization in structural design with uncertain parameters and stochastic processes  

NASA Technical Reports Server (NTRS)

The application of multiobjective optimization techniques to structural design problems involving uncertain parameters and random processes is studied. The design of a cantilever beam with a tip mass subjected to a stochastic base excitation is considered for illustration. Several of the problem parameters are assumed to be random variables and the structural mass, fatigue damage, and negative of natural frequency of vibration are considered for minimization. The solution of this three-criteria design problem is found by using global criterion, utility function, game theory, goal programming, goal attainment, bounded objective function, and lexicographic methods. It is observed that the game theory approach is superior in finding a better optimum solution, assuming the proper balance of the various objective functions. The procedures used in the present investigation are expected to be useful in the design of general dynamic systems involving uncertain parameters, stochastic process, and multiple objectives.

Rao, S. S.

1984-01-01

229

Aperiodic signals processing via parameter-tuning stochastic resonance in a photorefractive ring cavity  

SciTech Connect

Based on solving numerically the generalized nonlinear Langevin equation describing the nonlinear dynamics of stochastic resonance by Fourth-order Runge-Kutta method, an aperiodic stochastic resonance based on an optical bistable system is numerically investigated. The numerical results show that a parameter-tuning stochastic resonance system can be realized by choosing the appropriate optical bistable parameters, which performs well in reconstructing aperiodic signals from a very high level of noise background. The influences of optical bistable parameters on the stochastic resonance effect are numerically analyzed via cross-correlation, and a maximum cross-correlation gain of 8 is obtained by optimizing optical bistable parameters. This provides a prospective method for reconstructing noise-hidden weak signals in all-optical signal processing systems.

Li, Xuefeng, E-mail: lixfpost@163.com [School of Science, Xi'an University of Post and Telecommunications, Xi'an, 710121 (China)] [School of Science, Xi'an University of Post and Telecommunications, Xi'an, 710121 (China); Cao, Guangzhan; Liu, Hongjun [Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710119 (China)] [Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710119 (China)

2014-04-15

230

MODELING AND OPTIMIZATION OF PROCESS PARAMETERS FOR DELAMINATION IN DRILLING GLASS FIBER REINFORCED PLASTIC (GFRP) COMPOSITES  

Microsoft Academic Search

Glass fiber-reinforced composite materials are used in varieties of applications due to their excellent properties. Drilling is an indispensable process for this kind of materials. Delamination due to drilling is an important concern and is to be reduced. In the present work, drilling tests were carried out on computer numeric control (CNC) drilling machine. The parameters considered for the drilling

B. Latha; V. S. Senthilkumar; K. Palanikumar

2011-01-01

231

Effect of Die Dimensions on Extrusion Processing Parameters and Properties of DDGS-Based Aquaculture Feeds  

Technology Transfer Automated Retrieval System (TEKTRAN)

The goal of this study was to investigate the effect of die nozzle dimensions, barrel temperature profile, and moisture content on DDGS-based extrudate properties and extruder processing parameters. An ingredient blend containing 40% distillers dried grains with solubles (DDGS), along with soy flou...

232

Effect of processing parameters on surface finish for fused deposition machinable wax patterns  

NASA Technical Reports Server (NTRS)

This report presents a study on the effect of material processing parameters used in layer-by-layer material construction on the surface finish of a model to be used as an investment casting pattern. The data presented relate specifically to fused deposition modeling using a machinable wax.

Roberts, F. E., III

1995-01-01

233

Analysis of the film stacking processing parameters for PLLA/flax fibre biocomposites  

E-print Network

1 Analysis of the film stacking processing parameters for PLLA/flax fibre biocomposites P. Ouagne et al. [1] showed that biodegradable PLLA (L-polylactide acid)/flax fibres mat composites exhibiting, the compaction of flax mats requires a higher load than for glass mats of similar areal weight. The transverse

Brest, Université de

234

Recursive parameter estimation of an autoregressive process disturbed by white noise  

Microsoft Academic Search

The problem of estimating parameters of an autoregressive process based on the data corrupted by unknown white noise is considered. We shall mainly discuss two methods, the one based on the Yule–Walker equations and the other based on the modified least-squares estimation previously proposed by Sagara and Wada. The latter is based on the fact that a consistent estimator may

HIDEAKI SAKAI; MASAHIRO ARASE

1979-01-01

235

Effect of fabrication process parameters on the apex-radius of STM tungsten nanotip.  

PubMed

Scanning tunneling microscope (STM) has found a wide application in nanoscience and nanotechnology. This microscope uses an ultra-sharp metallic tip for image acquisition. Resolution of STM images depends largely on the radius of the tip apex; the smaller the radius the higher the resolution. In the present research, an experimental set-up was designed and implemented for fabrication of STM tungsten nanotip using electrochemical-etching method with the aim of optimization of nanotip fabrication process parameters by using Taguchi method. These parameters are electrolyte concentration, immersion length of the tungsten wire, inner diameter of the cathode tube, and the process voltage. It was found that the optimum level of the process parameters for gaining minimum radius of the nanotip apex is electrolyte concentration of 2 M/lit, wire immersion length of 4 mm, cathode tube inner diameter of 55 mm, and voltage of 3.5 V within the range of experiments. By setting the process parameters on the optimum level, the radius of the nanotip apex was decreased by five times in comparison to the mean value of the experimental results. The radius of the nanotip apex was improved down to about 10 nm under the optimum conditions. SCANNING 31: 65-74, 2009. (c) 2009 Wiley Periodicals, Inc. PMID:19191264

Tahmasebipour, Gh; Hojjat, Y; Ahmadi, V; Abdullah, A

2009-01-01

236

A neural network approach to characterize pattern parameters in process control charts  

Microsoft Academic Search

Abnormal patterns on manufacturing process control charts can reveal potential quality problems due to assignable causes at an early stage, helping to prevent defects and improve quality performance. In recent years, neural networks have been applied to the pattern recognition task for control charts. The emphasis has been on pattern detection and identification rather than more detailed pattern parameter information,

R.-S. Guh; J. D. T. Tannock

1999-01-01

237

Parameter-Specific Ring Oscillator for Process Monitoring at the 45 nm Node  

E-print Network

, the nomenclature used for the RO monitors is described in Table 1. The ROs are grouped into categories according to the process parameter that is being monitored: C= Control (with one dummy poly on each side of the gate), I Table 1. Nomenclature used for RO monitors Each RO is replicated 12 times with other circuits in a local

Nikolic, Borivoje

238

An IRT Model with a Parameter-Driven Process for Change  

ERIC Educational Resources Information Center

An IRT model with a parameter-driven process for change is proposed. Quantitative differences between persons are taken into account by a continuous latent variable, as in common IRT models. In addition, qualitative inter-individual differences and auto-dependencies are accounted for by assuming within-subject variability with respect to the…

Rijmen, Frank; De Boeck, Paul; van der Maas, Han L. J.

2005-01-01

239

Estimating dynamic transmission parameters of the SIR model based on a kernel-based Gaussian process  

NASA Astrophysics Data System (ADS)

In this paper a new approach for estimating parameters used in the SIR model is given. The Gaussian processes is used for modeling fluctuation of the new infected individuals. We introduce a Gaussian kernel for measuring the correlation within the reported new infected individuals. Numerical results show that the proposed method gives stable estimation with respect to noise level of the new infected data.

Indratno, S. W.; Shabrina, A.

2014-02-01

240

Net-Shape Forging of Aerofoil Blade based on Flash Trimming and Compensation methods  

SciTech Connect

In this research, an automatic blade forging die shape optimisation system was developed by using direct compensation and flash trimming algorithms and integrating with the DEFORM 3D software package. To validate the developed system, a 3D blade forging case problem was simulated and optimised with and without the consideration of trimming simulation. The results were compared with actual measurement data of the forged aerofoil blade with excellent results obtained with the fast trimming simulation procedure used.

Lu, B. [Department of Plasticity Forming Engineering, Shanghai Jiao Tong University, Shanghai, 200030 (China); Ou, H. [Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Armstrong, C. G. [School of Mechanical and Aerospace Engineering, Queen's University Belfast, Belfast, BT9 5AH (United Kingdom)

2011-05-04

241

Residual Stresses in 21-6-9 Stainless Steel Warm Forgings  

SciTech Connect

Forging residual stresses are detrimental to the production and performance of derived machined parts due to machining distortions, corrosion drivers and fatigue crack drivers. Residual strains in a 21-6-9 stainless steel warm High Energy Rate Forging (HERF) were measured via neutron diffraction. The finite element analysis (FEA) method was used to predict the residual stresses that occur during forging and water quenching. The experimentally measured residual strains were used to calibrate simulations of the three-dimensional residual stress state of the forging. ABAQUS simulation tools predicted residual strains that tend to match with experimental results when varying yield strength is considered.

Everhart, Wesley A.; Lee, Jordan D.; Broecker, Daniel J.; Bartow, John P.; McQueen, Jamie M.; Switzner, Nathan T.; Neidt, Tod M.; Sisneros, Thomas A.; Brown, Donald W.

2012-11-14

242

Direct extrusion process analysis with proposed numerical modeling improvements - product quality, process parameters, and microstructure prediction  

NASA Astrophysics Data System (ADS)

A numerical modeling and simulation analysis was performed on the hot-direct extrusion process with the finite element modeling (FEM) software package, DEFORM(TM) 3-D for three case studies. The research demonstrated that a commercially available, industry-accepted numerical simulation software package can predict the material response and microstructure development with simple simulated state variables (i.e. strain, strain rate, and temperature) and easily measured initial material characteristics (e.g. grain diameter). The predicted state variables provided insight into sources for limited extrudate quality, aided in processing improvements, and were the primary variables used to predict material response. The analysis began with studying the influence of tool misalignment and the degree of billet upset on extrudate dimensional quality, measured in terms of tube eccentricity, for a copper tube case study. Under ideal upset and tool alignment conditions, the simulated eccentricity was minimized. If the mandrel had a misalignment that was within tolerance, the eccentricity initially was minor in comparison to the eccentricity produced toward the end of extrusion. Consequently, through the use of DEFORM(TM) 3-D the extrusion mechanics were understood and sources for tube eccentricity were identified. In the second case study, a flow stress model was developed as a function of the state variables for an as-cast homogenized magnesium alloy. The modeled flow stress curve reasonably agreed with experimental compression flow stress data. The model was then implemented into DEFORM(TM) 3-D to utilize the simulated state variables to examine the extrusion of an automobile structural component. It was concluded that once the initial material characteristics are accounted for in the flow stress model it will more accurately and efficiently predict the flow stress response for the actual material being considered than a generic experimental flow stress-based material library entry in DEFORM(TM) 3-D. The third case study assessed an aluminum alloy's microstructure response to hot-direct extrusion processing conditions. The DEFORM(TM) 3-D simulated state variables were incorporated into a dynamic recrystallization (DRX) model that with reasonable accuracy predicted the surface grain structure evolution when compared to experimental results. By knowing the grain structure response the surface physical properties of the extrudate can be deduced.

de Pari, Luigi, Jr.

2009-11-01

243

A predictive thermal dynamic model for parameter generation in the laser assisted direct write process  

NASA Astrophysics Data System (ADS)

The laser assisted direct write (LADW) method can be used to generate electrical circuitry on a substrate by depositing metallic ink and curing the ink thermally by a laser. Laser curing has emerged over recent years as a novel yet efficient alternative to oven curing. This method can be used in situ, over complicated 3D contours of large parts (e.g. aircraft wings) and selectively cure over heat sensitive substrates, with little or no thermal damage. In previous studies, empirical methods have been used to generate processing windows for this technique, relating to the several interdependent processing parameters on which the curing quality and efficiency strongly depend. Incorrect parameters can result in a track that is cured in some areas and uncured in others, or in damaged substrates. This paper addresses the strong need for a quantitative model which can systematically output the processing conditions for a given combination of ink, substrate and laser source; transforming the LADW technique from a purely empirical approach, to a simple, repeatable, mathematically sound, efficient and predictable process. The method comprises a novel and generic finite element model (FEM) that for the first time predicts the evolution of the thermal profile of the ink track during laser curing and thus generates a parametric map which indicates the most suitable combination of parameters for process optimization. Experimental data are compared with simulation results to verify the accuracy of the model.

Shang, Shuo; Fearon, Eamonn; Wellburn, Dan; Sato, Taku; Edwardson, Stuart; Dearden, G.; Watkins, K. G.

2011-11-01

244

Identification of sensitive parameters in the modeling of SVOC reemission processes from soil to atmosphere.  

PubMed

Semi-volatile organic compounds (SVOCs) are subject to Long-Range Atmospheric Transport because of transport-deposition-reemission successive processes. Several experimental data available in the literature suggest that soil is a non-negligible contributor of SVOCs to atmosphere. Then coupling soil and atmosphere in integrated coupled models and simulating reemission processes can be essential for estimating atmospheric concentration of several pollutants. However, the sources of uncertainty and variability are multiple (soil properties, meteorological conditions, chemical-specific parameters) and can significantly influence the determination of reemissions. In order to identify the key parameters in reemission modeling and their effect on global modeling uncertainty, we conducted a sensitivity analysis targeted on the 'reemission' output variable. Different parameters were tested, including soil properties, partition coefficients and meteorological conditions. We performed EFAST sensitivity analysis for four chemicals (benzo-a-pyrene, hexachlorobenzene, PCB-28 and lindane) and different spatial scenari (regional and continental scales). Partition coefficients between air, solid and water phases are influent, depending on the precision of data and global behavior of the chemical. Reemissions showed a lower variability to soil parameters (soil organic matter and water contents at field capacity and wilting point). A mapping of these parameters at a regional scale is sufficient to correctly estimate reemissions when compared to other sources of uncertainty. PMID:24954563

Loizeau, Vincent; Ciffroy, Philippe; Roustan, Yelva; Musson-Genon, Luc

2014-09-15

245

Meltlets® of Soy Isoflavones: Process Optimization and the Effect of Extrusion Spheronization Process Parameters on Antioxidant Activity  

PubMed Central

In the current research work an attempt was made to develop “Melt in mouth pellets” (Meltlets®) containing 40% herbal extract of soy isoflavones that served to provide antioxidants activity in menopausal women. The process of extrusion–spheronization was optimized for extruder speed, extruder screen size, spheronization speed, and time. While doing so the herbal extract incorporated in the pellet matrix was subjected to various processing conditions such as the effect of the presence of other excipients, mixing or kneading to prepare wet mass, heat generated during the process of extrusion, spheronization, and drying. Thus, the work further investigates the effect of these processing parameters on the antioxidant activity of the soy isoflavone herbal extract incorporated in the formula. Thereby, the antioxidant activity of the soya bean herbal extract, Meltlets® and of the placebo pellets was evaluated using DPPH free radical scavenging assay and total reduction capacity. PMID:24302800

Deshmukh, Ketkee; Amin, Purnima

2013-01-01

246

The influence of process parameters on the laser-induced coloring of titanium  

NASA Astrophysics Data System (ADS)

This paper presents the results of the measurements and analysis of the influence of laser process parameters on the color obtained. The study was conducted for titanium (Grade 2) using a commercially available industrial pulsed fiber laser. It was determined how a variety of different laser process parameters, such as laser power, the scanning speed of the material, the temperature of the material, the size of the marked area, and the position of the sample, relative to both the focal plane and the center of the working field of the system, affect the repeatability of the colors created. For an objective assessment of color changes, an optical spectrometer and the CIE color difference parameter were used. Our paper explains why the tolerance of process parameters highly depends on the specific color. Additionally, a comparison of the results for titanium with those obtained for stainless steel in a previous study is presented. Based on this analysis, a number of necessary modifications are proposed to laser systems commonly used for monochrome marking in order to improve repeatability in color marking.

Anto?czak, Arkadiusz J.; St?pak, Bogusz; Kozio?, Pawe? E.; Abramski, Krzysztof M.

2014-06-01

247

Translational Research: Forging a New Cultural Identity  

PubMed Central

More than a decade ago, Dr. Joseph Goldstein called attention to the increasing dissociation between scientific advances and their translation into improved health with his pithy analysis of the biotechnology industry: “1 new gene per day, 1 new company per week, 1 new drug per year.”1 Unfortunately, the gap continues to grow, with increasing concerns about whether the enormous increase in knowledge brought about by the sequencing of the human genome and other scientific advances are being matched by the translational effort. For example, a recent review by the Congressional Budget Office found that the dramatic increase in inflation-adjusted funding of biomedical research since 1970 by the pharmaceutical industry and the National Institutes of Health (NIH), in addition to the influx of capital from the biotechnology industry, has had only a minor impact on the number of truly new drugs approved by the Food and Drug Administration each year.2 The outlook for the immediate future does not appear to be much brighter, with declining numbers of new drugs being submitted for regulatory approval3 and the investment community expressing grave concerns about the prospects for both the biotechnology and pharmaceutical industries.4,5 It is not surprising, therefore, that there has been intense focus on how to successfully bridge the gap between scientific discovery and the development of new strategies to diagnose, treat, and prevent disease; this process is now commonly called translational research. PMID:18828172

Coller, Barry S.

2009-01-01

248

Identification of sorption processes and parameters for radionuclide transport in fractured rock  

NASA Astrophysics Data System (ADS)

SummaryIdentification of chemical reaction processes in subsurface environments is a key issue for reactive transport modeling because simulating different processes requires developing different chemical-mathematical models. In this paper, two sorption processes (equilibrium and kinetics) are considered for modeling neptunium and uranium sorption in fractured rock. Based on different conceptualizations of the two processes occurring in fracture and/or matrix media, seven dual-porosity, multi-component reactive transport models are developed. The process models are identified with a stepwise strategy by using multi-tracer concentration data obtained from a series of transport experiments. In the first step, breakthrough data of a conservative tracer (tritium) obtained from four experiments are used to estimate the flow and non-reactive transport parameters (i.e., mean fluid residence time in fracture, fracture aperture, and matrix tortuosity) common to all the reactive transport models. In the second and third steps, by fixing the common non-reactive flow and transport parameters, the sorption parameters (retardation factor, sorption coefficient, and kinetic rate constant) of each model are estimated using the breakthrough data of reactive tracers, neptunium and uranium, respectively. Based on the inverse modeling results, the seven sorption-process models are discriminated using four model discrimination (or selection) criteria, Akaike information criterion ( AIC), modified Akaike information criterion ( AICc), Bayesian information criterion ( BIC) and Kashyap information criterion ( KIC). These criteria suggest the kinetic sorption process for modeling reactive transport of neptunium and uranium transport in both fracture and matrix. This conclusion is confirmed by two chemical criteria, the half reaction time and Damköhler number criterion.

Dai, Zhenxue; Wolfsberg, Andrew; Reimus, Paul; Deng, Hailin; Kwicklis, Edward; Ding, Mei; Ware, Doug; Ye, Ming

2012-01-01

249

Influence of introduction devices on crystallisation kinetic parameters in a supercritical antisolvent process  

NASA Astrophysics Data System (ADS)

Supercritical CO2 antisolvent processes developed in this work are based on two different introduction devices: the Concentric Tube Antisolvent Reactor (a capillary centred in a larger tube) and the Impinging Jet Technology (organic solution and supercritical CO2 impinging face to face). Griseofulvin pharmaceutical compound is chosen to test those two processes. The different experimental results indicate the same trends as classical supercritical antisolvent process for the evolution of particle size and particle size distribution with process parameters (mainly concentrations and flow rates). The second and main part is dedicated to the use of these experimental results for deriving modelling evaluation. Concerning this part, it is first shown that, in a first approximation, these processes can be represented by a continuous, mixed suspension and mixed product removal crystallizer. This allows modelling the mass particle size distribution. It also allows giving some numerical data on kinetics parameters (nucleation and growth). Secondly, general kinetic laws are derived for each process. In particular in the case of the impinging jet technology, the energy dissipated in the medium by the flow rates must be included in the crystallisation kinetic law.

Boutin, Olivier

2012-03-01

250

Effects of HVOF Process Parameters on the Properties of Ni-Cr Coatings  

NASA Astrophysics Data System (ADS)

This research examined the influence of processing parameters on the structure of a Ni-50Cr coating applied by high-velocity oxy-fuel spraying onto stainless steel specimens. This type of coating is normally used as protection against heat and corrosion encountered in power plant and marine boilers, and oil refinery heaters. A statistical design of experiments identified fuel and oxygen flow rates and spraying distance as the most influential parameters controlling the in-flight characteristics of the powder particles prior to impact. The effects of these parameters on the porosity level, oxide content, and microhardness of the coatings were then investigated in more detail. These results indicated that the oxide content and hardness of the coatings were dependent on the gas combustion ratio but not on spraying distance. The porosity level and amount of unmelted particles were reduced at the longest spraying distance.

Saaedi, J.; Coyle, T. W.; Arabi, H.; Mirdamadi, S.; Mostaghimi, J.

2010-03-01

251

Plasma and mechanical properties and process parameter selection criteria for laser rapid manufacturing  

NASA Astrophysics Data System (ADS)

Laser-based techniques to fabricate parts from non- polymer material have been developed in the past years. These processes are referred to as Solid Freeform Fabrication, Rapid Manufacturing, Positive Shaping, Rapid Tooling, and Near-Net Shape Fabrication. Data concerning the energy transfer from the processing laser beam to the material powder, such as the metal vapor-plasma plume temperature and plume absorption coefficient, the efficiency of laser energy transfer and mathematical analysis for the thermal and dimensional process characteristics are unavailable. Furthermore, guidelines to select process parameters (power, scanning speed, and powder feed rate) have not been investigated. The above-mentioned part fabrication techniques are not fully useful without predictive capability to calculate the geometries of the fabricated parts or the expected yield and ultimate strengths. Similarly, any operator needs a set of process parameter selection rules to identify stable operating conditions that result in a continuous powder deposition. Furthermore, it is difficult to determine for any material or alloy the operating conditions that result in a stable powder deposition process. Therefore, it is highly desirable to have a set of selection rules to determine the stable operating regime for any material based on the known stable process parameters of a given material. A one-dimensional model to calculate the thermal and dimensional process characteristics is developed. The model accounts for the transmission of the laser beam through the plume, energy transfer in the molten phase and the Stefan conditions at the solid-liquid and liquid- vapor interfaces. The model is used to determine the amount of energy transferred from the laser beam to the powder. A set of dimensionless numbers characterizing the powder deposition process is identified using Buckingham's ?-Theorem. These numbers are used to represent the stable and unstable operating regimes and to apply the stable operating conditions of a known material to other materials. Mechanical properties such as yield and ultimate strengths of laser-fabricated stainless steel (SS 304) parts have been measured and correlated to the operating conditions through the dimensionless similarity parameters. A model, accounting for directionally preferred solidification, to calculate the residual stresses generated in the part during solidification is developed.

Kahlen, Franz-Josef

2000-08-01

252

SourceForge.net: Project of the Month  

NSDL National Science Digital Library

SourceForge, described as the most prominent repository of open source software, selects an outstanding contribution to recognize on its Project of the Month Web site. As with all open source projects, the software can be freely downloaded, used, and modified. Examples of past projects of the month include an instant messaging client, a 3D game developing kit, and a tool for porting applications from UNIX to the Macintosh OS X operating system. A description of the project and an interview with the project's creator showcase the software.

253

SAR image post-processing for the estimation of fractal parameters  

NASA Astrophysics Data System (ADS)

In this paper a fractal based processing for the analysis of SAR images of natural surfaces is presented. Its definition is based on a complete direct imaging model developed by the authors. The application of this innovative algorithm to SAR images makes possible to obtain complete maps of the two key parameters of a fractal scene: the fractal dimension and the increment standard deviation. The fractal parameters extraction is based on the estimation of the power spectral density of the SAR amplitude image. From a theoretic point of view, the attention is focused on the retrieving procedure of the increment standard deviation, here presented for the first time. In the last section of the paper, the application of the introduced processing to high resolution SAR images is presented, with the relevant maps of the fractal dimension and of the increment standard deviation.

Di Martino, Gerardo; Riccio, Daniele; Ruello, Giuseppe; Zinno, Ivana

2011-11-01

254

Post-processing of seismic parameter data based on valid seismic event determination  

DOEpatents

An automated seismic processing system and method are disclosed, including an array of CMOS microprocessors for unattended battery-powered processing of a multi-station network. According to a characterizing feature of the invention, each channel of the network is independently operable to automatically detect, measure times and amplitudes, and compute and fit Fast Fourier transforms (FFT's) for both P- and S- waves on analog seismic data after it has been sampled at a given rate. The measured parameter data from each channel are then reviewed for event validity by a central controlling microprocessor and if determined by preset criteria to constitute a valid event, the parameter data are passed to an analysis computer for calculation of hypocenter location, running b-values, source parameters, event count, P- wave polarities, moment-tensor inversion, and Vp/Vs ratios. The in-field real-time analysis of data maximizes the efficiency of microearthquake surveys allowing flexibility in experimental procedures, with a minimum of traditional labor-intensive postprocessing. A unique consequence of the system is that none of the original data (i.e., the sensor analog output signals) are necessarily saved after computation, but rather, the numerical parameters generated by the automatic analysis are the sole output of the automated seismic processor.

McEvilly, Thomas V. (733 Alvarado Rd., Berkeley, CA 94705)

1985-01-01

255

Statistical optimization of process parameters on biohydrogen production from glucose by Clostridium sp. Fanp2  

Microsoft Academic Search

Statistically based experimental designs were applied to optimizing process parameters for hydrogen production from glucose by Clostridium sp. Fanp2 which was isolated from effluent sludge of anaerobic hydrogen-producing bioreactor. The important factors influencing hydrogen production, which identified by initial screening method of Plackett–Burman, were glucose, phosphate buffer and vitamin solution. The path of steepest ascent was undertaken to approach the

C. M. Pan; Y. T. Fan; Y. Xing; H. W. Hou; M. L. Zhang

2008-01-01

256

Calculation of process parameters in the manufacture of a panel with a corrugated core  

NASA Astrophysics Data System (ADS)

A method is presented for calculating the parameters of a process for producing multilayer curved panels with a lightweight corrugated core. The method provides a way to achieve precision in panel manufacture by shaping the core in accordance with the required curvature during the forming of the core. The structure and the density of the core can be varied in accordance with the desired functional application of the panels.

Khaliulin, V. I.; Desiatov, V. E.

257

Subsonic flight test evaluation of a propulsion system parameter estimation process for the F100 engine  

NASA Technical Reports Server (NTRS)

Integrated engine-airframe optimal control technology may significantly improve aircraft performance. This technology requires a reliable and accurate parameter estimator to predict unmeasured variables. To develop this technology base, NASA Dryden Flight Research Facility (Edwards, CA), McDonnell Aircraft Company (St. Louis, MO), and Pratt & Whitney (West Palm Beach, FL) have developed and flight-tested an adaptive performance seeking control system which optimizes the quasi-steady-state performance of the F-15 propulsion system. This paper presents flight and ground test evaluations of the propulsion system parameter estimation process used by the performance seeking control system. The estimator consists of a compact propulsion system model and an extended Kalman filter. The extended Laman filter estimates five engine component deviation parameters from measured inputs. The compact model uses measurements and Kalman-filter estimates as inputs to predict unmeasured propulsion parameters such as net propulsive force and fan stall margin. The ability to track trends and estimate absolute values of propulsion system parameters was demonstrated. For example, thrust stand results show a good correlation, especially in trends, between the performance seeking control estimated and measured thrust.

Orme, John S.; Gilyard, Glenn B.

1992-01-01

258

Effects of material variables and process parameters on properties of investment casting shells  

NASA Astrophysics Data System (ADS)

Manufacture of investment casting shells is a complex process. The choice of raw materials - refractory powders or grains, binders and additives - affects the properties of investment casting shells. In this study, different systems of shells were prepared, according to a design of experiments, with commercially available raw materials that differ in chemistry, particle size or particle size distribution. Shell strength was measured in green, fired and cooled, and hot conditions and the results were analyzed for strength -- material property relation. Various microstructures of polished cross sections of these shells were characterized using scanning electron microscope. It was determined that the amount of matrix holding the stucco grains was dominant factor affecting green strength. Fired and hot strengths were observed to vary depending on interactions between different phases of matrix and stucco. In addition to the material properties, control of shell building parameters is critical to achieve quality shells. Process parameters affect strength of the shell by providing a means to change the relative amounts of stucco, slurry and porosity. To study the microstructural variations, shells were prepared by varying process parameters like slurry viscosity and stucco size. Data from image analysis of different microstructures were correlated to their respective fired strengths. It was determined that the shells prepared from high viscosity slurry and fine stucco had the highest strength.

Tumurugoti, Priyatham

259

Science Education and Outreach: Forging a Path to the Future ASP Conference Series, Vol. **VOLUME**, c 2010  

E-print Network

Science Education and Outreach: Forging a Path to the Future ASP Conference Series, Vol. **VOLUME timely to think about the successes of the year and, as this ASP annual meeting title indicates, forge

Hillenbrand, Lynne

260

Structural changes of radial forging die surface during service under thermo-mechanical fatigue  

Microsoft Academic Search

Radial forging is one of the modern open die forging techniques and has a wide application in producing machine parts. During operation at high temperatures, severe temperature change associated with mechanical loads and the resultant wearing of the die surface lead to intense variation in strain on the die surface. Therefore, under this operating condition, thermo-mechanical fatigue (TMF) occurs on

Fardin Nematzadeh; Mohammad Reza Akbarpour; Amir Hosein Kokabi; Seyed Khatiboleslam Sadrnezhaad

2009-01-01

261

Treatment of simulated industrial wastewater by photo-Fenton process. Part I: The optimization of process parameters using design of experiments (DOE)  

Microsoft Academic Search

The study reported the application of the photo-Fenton process for the treatment of simulated industrial wastewater upon pretreatment by the dark-Fenton process. The process efficiency which depends on several important process parameters such as initial pH, iron catalyst and oxidant concentration, and the UV irradiation type, was investigated. To consider the combined effects of studied process parameters, three-factor three-level Box–Behnken

Marina Dopar; Hrvoje Kusic; Natalija Koprivanac

2011-01-01

262

Quantitative analysis of beam delivery parameters and treatment process time for proton beam therapy  

SciTech Connect

Purpose: To evaluate patient census, equipment clinical availability, maximum daily treatment capacity, use factor for major beam delivery parameters, and treatment process time for actual treatments delivered by proton therapy systems. Methods: The authors have been recording all beam delivery parameters, including delivered dose, energy, range, spread-out Bragg peak widths, gantry angles, and couch angles for every treatment field in an electronic medical record system. We analyzed delivery system downtimes that had been recorded for every equipment failure and associated incidents. These data were used to evaluate the use factor of beam delivery parameters, the size of the patient census, and the equipment clinical availability of the facility. The duration of each treatment session from patient walk-in and to patient walk-out of the treatment room was measured for 82 patients with cancers at various sites. Results: The yearly average equipment clinical availability in the last 3 yrs (June 2007-August 2010) was 97%, which exceeded the target of 95%. Approximately 2200 patients had been treated as of August 2010. The major disease sites were genitourinary (49%), thoracic (25%), central nervous system (22%), and gastrointestinal (2%). Beams have been delivered in approximately 8300 treatment fields. The use factor for six beam delivery parameters was also evaluated. Analysis of the treatment process times indicated that approximately 80% of this time was spent for patient and equipment setup. The other 20% was spent waiting for beam delivery and beam on. The total treatment process time can be expressed by a quadratic polynomial of the number of fields per session. The maximum daily treatment capacity of our facility using the current treatment processes was estimated to be 133 {+-} 35 patients. Conclusions: This analysis shows that the facility has operated at a high performance level and has treated a large number of patients with a variety of diseases. The use factor of beam delivery parameters varies by disease site. Further improvements in efficiency may be realized in the equipment- and patient-related processes of treatment.

Suzuki, Kazumichi; Gillin, Michael T.; Sahoo, Narayan; Zhu, X. Ronald; Lee, Andrew K.; Lippy, Denise [Departments of Radiation Physics and Radiation Oncology, University of Texas, MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); The Proton Therapy Center Houston, Ltd., L.L.P., 1840 Old Spanish Trail, Houston, Texas 77054 (United States)

2011-07-15

263

Ultrasonic phased arrays for nondestructive inspection of forgings  

SciTech Connect

Ultrasonic examinations on large forgings like rotor shafts for turbines or components for nuclear reactors are carried out at various manufacturing stages and during in-service inspections. During the manufacture, most of the inspections are carried out manually. Special in-service conditions, such as those at nuclear pressure vessels, have resulted in the development of mechanized scanning equipment. Ultrasonic probes have improved, and well-adapted sound fields and pulse shapes and based on special imaging procedures for the representation of the reportable reflectors have been applied. Since the geometry of many forgings requires the use of a multitude of angles for the inspections in-service and during manufacture, phased-array probes can be used successfully. The main advantages of the phased-array concept, e.g. the generation of a multitude of angles with the typical increase of redundancy in detection and quantitative evaluation and the possibility to produce pictures of defect situations, will be described in this contribution.

Wuestenberg, H.; Rotter, B. (Bundesanstalt fuer Materialforschung undpruefung, Berlin (Germany)); Klanke, H.P. (Vereinigte Schmiedegesellschaft, Osnabarueck (Germany)); Harbecke, D. (Krautkraemer, Huerth (Germany))

1993-06-01

264

Parameter Sensitivity and Laboratory Benchmarking of a Biogeochemical Process Model for Enhanced Anaerobic Dechlorination  

NASA Astrophysics Data System (ADS)

A detailed model to simulate trichloroethene (TCE) dechlorination in anaerobic groundwater systems has been developed and implemented through PHAST, a robust and flexible geochemical modeling platform. The approach is comprehensive but retains flexibility such that models of varying complexity can be used to simulate TCE biodegradation in the vicinity of nonaqueous phase liquid (NAPL) source zones. The complete model considers a full suite of biological (e.g., dechlorination, fermentation, sulfate and iron reduction, electron donor competition, toxic inhibition, pH inhibition), physical (e.g., flow and mass transfer) and geochemical processes (e.g., pH modulation, gas formation, mineral interactions). Example simulations with the model demonstrated that the feedback between biological, physical, and geochemical processes is critical. Successful simulation of a thirty-two-month column experiment with site soil, complex groundwater chemistry, and exhibiting both anaerobic dechlorination and endogenous respiration, provided confidence in the modeling approach. A comprehensive suite of batch simulations was then conducted to estimate the sensitivity of predicted TCE degradation to the 36 model input parameters. A local sensitivity analysis was first employed to rank the importance of parameters, revealing that 5 parameters consistently dominated model predictions across a range of performance metrics. A global sensitivity analysis was then performed to evaluate the influence of a variety of full parameter data sets available in the literature. The modeling study was performed as part of the SABRE (Source Area BioREmediation) project, a public/private consortium whose charter is to determine if enhanced anaerobic bioremediation can result in effective and quantifiable treatment of chlorinated solvent DNAPL source areas. The modelling conducted has provided valuable insight into the complex interactions between processes in the evolving biogeochemical systems, particularly at the laboratory scale.

Kouznetsova, I.; Gerhard, J. I.; Mao, X.; Barry, D. A.; Robinson, C.; Brovelli, A.; Harkness, M.; Fisher, A.; Mack, E. E.; Payne, J. A.; Dworatzek, S.; Roberts, J.

2008-12-01

265

An evaluation of process parameters to improve coating efficiency of an active tablet film-coating process.  

PubMed

Effects of material and manufacturing process parameters on the efficiency of an aqueous active tablet film-coating process in a perforated pan coater were evaluated. Twenty-four batches representing various core tablet weights, sizes, and shapes were coated at the 350-500 kg scale. The coating process efficiency, defined as the ratio of the amount of active deposited on tablet cores to the amount of active sprayed, ranged from 86 to 99%. Droplet size and velocity of the coating spray were important for an efficient coating process. Factors governing them such as high ratios of the suspension spray rate to atomization air flow rate, suspension spray rate to pattern air flow rate, or atomization air flow rate to pattern air flow rate improved the coating efficiency. Computational fluid dynamics modeling of the droplets showed that reducing the fraction of the smaller droplets, especially those smaller than 10 ?m, resulted in a marked improvement in the coating efficiency. Other material and process variables such as coating suspension solids concentration, pan speed, tablet velocity, exhaust air temperature, and the length of coating time did not affect the coating efficiency profoundly over the ranges examined here. PMID:22301427

Wang, Jennifer; Hemenway, Jeffrey; Chen, Wei; Desai, Divyakant; Early, William; Paruchuri, Srinivasa; Chang, Shih-Ying; Stamato, Howard; Varia, Sailesh

2012-05-10

266

Research into Oil-based Colloidal-Graphite Lubricants for Forging of Al-based Alloys  

SciTech Connect

The presented paper describes the topical problem in metal forging production. It deals with the choice of an optimal lubricant for forging of Al-based alloys. Within the scope of the paper, the properties of several oil-based colloidal-graphite lubricants were investigated. The physicochemical and technological properties of these lubricants are presented. It was found that physicochemical properties of lubricant compositions have an influence on friction coefficient value and quality of forgings.The ring compression method was used to estimate the friction coefficient value. Hydraulic press was used for the test. The comparative analysis of the investigated lubricants was carried out. The forging quality was estimated on the basis of production test. The practical recommendations were given to choose an optimal oil-based colloidal-graphite lubricant for isothermal forging of Al-based alloy.

Petrov, A.; Petrov, P.; Petrov, M. [Moscow State Technical University 'MAMI', Department of Autobody making and metal forging, B.Semenovskaya 38, 107023, Moscow (Russian Federation)

2011-05-04

267

Controlled drug release from melt-extrudates through processing parameters: A chemometric approach.  

PubMed

The objective of this study was to tailor a drug release profile through the adjustment of some key processing parameters involved in melt-extrusion: die temperature, shear rate, die length and drug particle size. Two experimental designs were selected, namely a 2-level full factorial design to examine the effects and significance of the processing factors, and a central composite design of the surface responses to find the best set of factor levels to obtain given specifications of drug release. Extrudates of poly(ethylene-co-vinyl acetate) and phenylpropanolamine hydrochloride were prepared using a ram extruder. Drug release profiles from the matrix systems were fitted using a power law, for which a new mathematical expression of a burst release was provided. The burst release and exponent were selected as the responses. The processing factors had a drastic influence on the drug release. Within the domain that was investigated, the burst release and the exponent varied from 6 to 54% and 0.1 to 0.4, respectively, resulting in a time requires for 50% drug release extending from hours to weeks. These results demonstrated the possibilities of modulating the release profile by means of the processing parameters rather than through the classical approach of altering the formulation. PMID:25543111

Sarraf, Abraham G; Cherkaoui, Samir; Jordan, Olivier; Gurny, Robert; Doelker, Eric

2015-03-15

268

Display device for indicating the value of a parameter in a process plant  

DOEpatents

An advanced control room complex for a nuclear power plant, including a discrete indicator and alarm system (72) which is nuclear qualified for rapid response to changes in plant parameters and a component control system (64) which together provide a discrete monitoring and control capability at a panel (14-22, 26, 28) in the control room (10). A separate data processing system (70), which need not be nuclear qualified, provides integrated and overview information to the control room and to each panel, through CRTs (84) and a large, overhead integrated process status overview board (24). The discrete indicator and alarm system (72) and the data processing system (70) receive inputs from common plant sensors and validate the sensor outputs to arrive at a representative value of the parameter for use by the operator during both normal and accident conditions, thereby avoiding the need for him to assimilate data from each sensor individually. The integrated process status board (24) is at the apex of an information hierarchy that extends through four levels and provides access at each panel to the full display hierarchy. The control room panels are preferably of a modular construction, permitting the definition of inputs and outputs, the man machine interface, and the plant specific algorithms, to proceed in parallel with the fabrication of the panels, the installation of the equipment and the generic testing thereof.

Scarola, Kenneth (Windsor, CT); Jamison, David S. (Windsor, CT); Manazir, Richard M. (North Canton, CT); Rescorl, Robert L. (Vernon, CT); Harmon, Daryl L. (Enfield, CT)

1993-01-01

269

Visualizing the influence of the process parameters on the keyhole dimensions in plasma arc welding  

NASA Astrophysics Data System (ADS)

The keyhole status and its dimensions are critical information determining both the process quality and weld quality in plasma arc welding (PAW). It is of great significance to measure the keyhole shape and size and to correlate them with the main process parameters. In this study, a low-cost vision system is developed to visualize the keyhole at the backside of the test-pieces in PAW. Three stages of keyhole evolution, i.e. initial blind stage (non-penetrated keyhole), unstable stage with momentarily disappeared keyhole and quasi-steady open keyhole stage (fully-penetrated keyhole), are measured in real-time during the PAW tests on stainless steel test-pieces of thickness 8 mm. Based on the captured images of keyhole under different welding conditions, the correlations of the main welding process parameters (welding current, welding speed, plasma gas flow rate) with the keyhole length, width and area are visualized through vision measurement. It lays a solid foundation for implementing keyhole stability control and process optimization in keyhole PAW.

Liu, Z. M.; Wu, C. S.; Chen, M. A.

2012-10-01

270

Determination Of Kinetic Parameters Of Combustion Processes Using Optical Detection Techniques  

NASA Astrophysics Data System (ADS)

The increased use of dirty fuels such as coal and oil shale in station-ary combustors has increased the necessity for controlling NOx emissions. A potential method to accomplish this goal is the thermal deN0x process, where ammonia added to the combustion exhaust gas chemically converts nitric oxide to harmless products (N2 and H20). A complete understanding of the chemical processes occurring has been hampered by a lack of detailed high-temperature kinetic data. Using a high-temperature fast flow reactor equipped with a variety of optical detection devices, key rate parameters and product channels are determined for this process, and, in conjunction with computer modeling, a consistent comprehensive model is developed which describes the features of the NHi/NOx chemical system.

Silver, Joel A.

1981-08-01

271

76 FR 5331 - Forged Stainless Steel Flanges From India and Taiwan: Final Results of Sunset Reviews and...  

Federal Register 2010, 2011, 2012, 2013, 2014

...A-533-809, A-583-821] Forged Stainless Steel Flanges From India and Taiwan...the antidumping duty orders on forged stainless steel flanges from India and Taiwan...antidumping duty orders on certain forged stainless steel flanges from India and...

2011-01-31

272

78 FR 8587 - Heraeus Kulzer, LLC., Including On-Site Leased Workers from People Link Staffing, Forge Staffing...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Including On-Site Leased Workers from People Link Staffing, Forge Staffing, Career Transitions...including on-site leased workers from People Link Staffing and Forge Staffing, South Bend...including on-site leased workers from People Link Staffing, Forge Staffing, Career...

2013-02-06

273

A self-adaptive parameter optimization algorithm in a real-time parallel image processing system.  

PubMed

Aiming at the stalemate that precision, speed, robustness, and other parameters constrain each other in the parallel processed vision servo system, this paper proposed an adaptive load capacity balance strategy on the servo parameters optimization algorithm (ALBPO) to improve the computing precision and to achieve high detection ratio while not reducing the servo circle. We use load capacity functions (LC) to estimate the load for each processor and then make continuous self-adaptation towards a balanced status based on the fluctuated LC results; meanwhile, we pick up a proper set of target detection and location parameters according to the results of LC. Compared with current load balance algorithm, the algorithm proposed in this paper is proceeded under an unknown informed status about the maximum load and the current load of the processors, which means it has great extensibility. Simulation results showed that the ALBPO algorithm has great merits on load balance performance, realizing the optimization of QoS for each processor, fulfilling the balance requirements of servo circle, precision, and robustness of the parallel processed vision servo system. PMID:24174920

Li, Ge; Zhang, Xuehe; Zhao, Jie; Zhang, Hongli; Ye, Jianwei; Zhang, Weizhe

2013-01-01

274

Neutron coincidence measurements when nuclear parameters vary during the multiplication process  

SciTech Connect

In a recent paper, a physical/mathematical model was developed for neutron coincidence counting, taking explicit account of neutron absorption and leakage, and using dual probability generating function to derive explicit formulae for the single and multiple count-rates in terms of the physical parameters of the system. The results of this modeling proved very successful in a number of cases in which the system parameters (neutron reaction cross-sections, detection probabilities, etc.) remained the same at the various stages of the process (i.e. from collision to collision). However, there are practical circumstances in which such system parameters change from collision to collision, and it is necessary to accommodate these, too, in a general theory, applicable to such situations. For instance, in the case of the neutron coincidence collar (NCC), the parameters for the initial, spontaneous fission neutrons, are not the same as those for the succeeding induced fission neutrons, and similar situations can be envisaged for certain other experimental configurations. This present document shows how the previous considerations can be elaborated to embrace these more general requirements.

Lu, Ming-Shih; Teichmann, T.

1995-07-01

275

Estimation of the soil strength parameters in Tertiary volcanic regolith (NE Turkey) using analytical hierarchy process  

NASA Astrophysics Data System (ADS)

Costly and time consuming testing techniques and the difficulties in providing undisturbed samples for these tests have led researchers to estimate strength parameters of soils with simple index tests. However, the paper focuses on estimation of strength parameters of soils as a function of the index properties. Analytical hierarchy process and multiple regression analysis based methodology were performed on datasets obtained from soil tests on 41 samples in Tertiary volcanic regolith. While the hierarchy model focused on determining the most important index properties affecting on strength parameters, regression analysis established meaningful relationships between strength parameters and index properties. The negative polynomial correlations between the friction angle and plasticity properties, and the positive exponential relations between the cohesion and plasticity properties were determined. These relations are characterized by a regression coefficient of 0.80. However, Terzaghi bearing capacity formulas were used to test the model. It is important to see whether there is any statistically significant relation between the calculated and the observed bearing capacity values for model testing. Based on the model, the positive linear correlation characterized by the regression coefficient of 0.86 were determined between bearing capacity values obtained by direct and indirect methods.

Ersoy, Hakan; Karsli, Melek Betül; Çellek, Seda; Kul, Bilgehan; Baykan, ?dris; Parsons, Robert L.

2013-12-01

276

Consolidation processing parameters and alternative processing methods for powder metallurgy Al-Cu-Mg-X-X alloys  

NASA Technical Reports Server (NTRS)

The effects of varying the vacuum degassing parameters on the microstructure and properties of Al-4Cu-1Mg-X-X (X-X = 1.5Li-0.2Zr or 1.5Fe-0.75Ce) alloys processed from either prealloyed (PA) or mechanically alloyed (M) powder, and consolidated by either using sealed aluminum containers or containerless vacuum hot pressing were studied. The consolidated billets were hot extruded to evaluate microstructure and properties. The MA Li-containing alloy did not include Zr, and the MA Fe- and Ce-containing alloy was made from both elemental and partially prealloyed powder. The alloys were vacuum degassed both above and below the solution heat treatment temperature. While vacuum degassing lowered the hydrogen content of these alloys, the range over which the vacuum degassing parameters were varied was not large enough to cause significant changes in degassing efficiency, and the observed variations in the mechanical properties of the heat treated alloys were attributed to varying contributions to strengthening by the sub-structure and the dispersoids. Mechanical alloying increased the strength over that of alloys of similar composition made from PA powder. The inferior properties in the transverse orientation, especially in the Li-containing alloys, suggested deficiencies in degassing. Among all of the alloys processed for this study, the Fe- and Ce-containing alloys made from MA powder possessed better combinations of strength and toughness.

Sankaran, K. K.

1987-01-01

277

Optimizing Process Parameters to Produce Single Phase YBa2Cu3O7 Powder  

NASA Technical Reports Server (NTRS)

Process parameters such as temperature and time are varied to obtain single phase (pure) YBa2Cu307 powders. X-ray diffraction patterns of superconducting and nonsuperconducting powders are observed in situ in normal and elevated temperature environments to confirm known strong peaks that are unique to YBa2Cu307. Peaks vary in magnitude as a result of superconducting - nonsuperconducting phase transitions. Known strong peaks serve as our basis in monitoring transitional changes. Peak isotherms obtained experimentally are correlated with theoretical models to identify the weighting factor that characterizes the optimum isotherm. By isolating the parameters under which 100% peak growth occurs most rapidly, we obtain the optimum isotherm. The choices made for firing temperature and atmosphere were determined to be the primary factors necessary to ensure sample purity.

Hurley, J. S.; Haimang, S. O.; Karikari, E. K.; Bassey, A.; SaDi, A.; Smith, M.

1996-01-01

278

Effect of process parameters on sidewall damage in deep silicon etch  

NASA Astrophysics Data System (ADS)

Sidewall damage caused in deep reactive ion silicon etch was investigated by varying etch cycle time, bias power, etch pressure and SF6 flow rate using the Bosch process in a uniquely designed, inductively coupled plasma reactor. The effects of these process parameters on the etch profile and sidewall angle were also studied for high density metal–insulator–metal capacitor structure. By choosing the proper etch cycle time of 2?s, it was observed that the sidewall damage was very sensitive to these etch process parameters. As bias power increased, the sidewall damage increased gradually. Especially, at the bias power of 500?W, a dual bowing shape with severe sidewall damage was seen, which might be due to a combination of two mechanisms: the formation of a redeposition region and a secondary ion etch effect. With increasing pressure, the sidewall damage was not always located in a specific depth range but distributed along almost the whole trench sidewall. An etch pressure below 80?mTorr was favorably recommended for reducing the extent of the sidewall damage. In addition, we found that an appropriate SF6 flow rate was also very beneficial to the realization of a smooth trench sidewall when it was controlled within an appropriate range. Based on these investigations, an acceptable etch condition could be selected to achieve a nearly vertical etch profile as well as a smooth sidewall surface.

Meng, Lingkuan; Yan, Jiang

2015-03-01

279

A Method to set process parameters of local squeeze in HPDC  

NASA Astrophysics Data System (ADS)

In HPDC processes, pressurization of the mushy regions via local squeeze pins and plunger during the intensification stage is very important to decrease porosity defects. In order to better understand the process and to be able to set the process parameters more properly, we developed a simulation code to solve the flow field of mushy regions and porosity formation based on the following main assumptions: 1) Local squeeze pins and plunger tip can be treated as pressure boundaries, while the squeeze pins are treated as moving boundaries. 2)The intensification and local squeeze pressure can propagate inside regions where the solid fraction is less than critical values. 3) In the pressurized regions, the cast metal is treated as a Newtonian fluid and both the solid and liquid flow together when the solid fraction is low, and the D'Arcy flow only exists when the solid fraction goes higher. 3) Only the liquid flows in the unpressurized regions, following the D'Arcy's law. 4) Porosities grow in elements when the pressure decreases below critical values depending on the element condition. The simulation was applied to HPDC castings and showed that the pressure-duration was similar to the measured one though the simulated pressure drop in the pressurized region was much smaller than the measured one. The pressure drop, pressure-duration and pin-penetration depth were discussed and the simulation seems to be helpful to determine local squeeze parameters. Future challenges are also discussed.

Ohnaka, I.; Zhu, J. D.; Sugiyama, A.; Kinoshita, F.

2012-07-01

280

Bioresorbable devices made of forged composites of hydroxyapatite (HA) particles and poly- L-lactide (PLLA): Part I. Basic characteristics  

Microsoft Academic Search

Compounds that had neither calcined nor sintered hydroxyapatite (u-HA) particles (particulate size 0.2–20?m, averaging 3.0?m, Ca\\/P=1.69, and containing CO2-3) uniformly distributed in a poly-L-lactide (PLLA, M?v: 400KDa) matrix with a content of 20–50wt% (with 10% increment) were reinforced into composites by a forging process, which was a unique compression molding, and were then machined on a lathe in order to

Y Shikinami; M Okuno

1999-01-01

281

Physiological description of multivariate interdependencies between process parameters, morphology and physiology during fed-batch penicillin production.  

PubMed

Optimization of productivity and economics of industrial bioprocesses requires characterization of interdependencies between process parameters and process performance. In the case of penicillin production, as in other processes, process performance is often closely interlinked with the physiology and morphology of the organism used for production. This study presents a systematic approach to efficiently characterize the physiological effects of multivariate interdependencies between bioprocess design parameters (spore inoculum concentration, pO2 control level and substrate feed rate), morphology, and physiology. Method development and application was performed using the industrial model process of penicillin production. Applying traditional, statistical bioprocess analysis, multivariate correlations of raw bioprocess design parameters (high spore inoculum concentration, low pO2 control as well as reduced glucose feeding) and pellet morphology were identified. A major drawback of raw design parameter correlation models; however, is the lack of transferability across different process scales and regimes. In this context, morphological and physiological bioprocess modeling based on scalable physiological parameters is introduced. In this study, raw parameter effects on pellet morphology were efficiently summarized by the physiological parameter of the biomass yield per substrate. Finally, for the first time to our knowledge, the specific growth rate per spore was described as time-independent determinant for switching from pellet to disperse growth during penicillin production and thus introduced as a novel, scalable key process parameter for pellet morphology and process performance. PMID:24616429

Posch, Andreas E; Herwig, Christoph

2014-01-01

282

Influence of processing parameters on the structure and properties of barium strontium titanate ceramics  

SciTech Connect

Barium strontium titanate (BST) with the molar formula (Ba{sub 0.8}Sr{sub 0.2}TiO{sub 3}) has been prepared by two different processing methods: mixed-oxide (BST-MO) and reaction-sintering (BST-RS). X-ray powder diffraction study shows differences in grain size and crystal symmetry for both these ceramics. The former shows a tetragonal symmetry while the latter presents a cubic symmetry. The occurrence of polar micro-regions associated with the higher chemical non-homogeneous distribution of ion defects from the influence of the processing parameters is the main reason for the higher peak dielectric constant (K{sub m}), the higher remanent polarization (P{sub r}), the higher coercive field (E{sub c}), the higher peak current density (J{sub m}), and the lower temperature of peak dielectric constant (T{sub m}) in BST-MO ceramics.

Yun Sining [School of Material Science and Engineering, Xi'an University of Architecture and Technology, Xi'an 710055 (China); Department of Materials Physics, School of Science, Xi'an Jiaotong University, Xi'an 710049 (China)], E-mail: alexsyun1974@yahoo.com.cn; Wang Xiaoli [Department of Materials Physics, School of Science, Xi'an Jiaotong University, Xi'an 710049 (China); Xu Delong [School of Material Science and Engineering, Xi'an University of Architecture and Technology, Xi'an 710055 (China)

2008-08-04

283

Low-dose capsule filling of inhalation products: critical material attributes and process parameters.  

PubMed

The aim of the present work was to identify the material attributes and process parameters of a dosator-nozzle capsule filling machine that are critical in low-fill weight capsule filling for inhalation therapies via hard-gelatin capsules. Twelve powders, mostly inhalation carriers, some fines and one proprietary active pharmaceutical ingredient (API), were carefully characterized and filled into size 3 capsules. Since different process conditions are required to fill capsules with powders that have very different material attributes, the powders were divided into two groups. A design of experiments (DOE) based exclusively on process parameters was developed for each group, to identify the critical material attributes (CMA) and critical process parameters (CPP). The fill weight (4-45 mg) of the group I powders (larger particles, higher density, better flowability and less cohesion) correlated with the nozzle diameter (1.9-3.4mm), the dosing chamber length (2.5-5mm), the powder layer depth (5-12.5mm) and the powder density (bulk and tapped density). The RSDs were acceptable in most cases, even for very low doses. The fill weight (1.5-21 mg) of group II powders (very fine and low dense particles with a particle size <10 ?m, poor flowability and higher cohesion) depended also on the nozzle diameter (1.9-2.8mm), the dosing chamber length (2.5-5mm) and the powder layer depth (5-10mm), albeit in a different way, indicating that for these powders dosator filling was not volumetric. Moreover, frictional (wall friction angle) and powder-flow characteristics (bulk density and basic flowability energy) have an influence on the mass. Thus, in summary, group I and group II powders can be filled successfully via dosator systems at low fill weights. However, the group II powders were more challenging to fill, especially without automated process control. This study is the first scientific qualification of dosator nozzles for low-fill weight (1-45 mg) capsule filling. PMID:25087508

Faulhammer, Eva; Fink, Marlies; Llusa, Marcos; Lawrence, Simon M; Biserni, Stefano; Calzolari, Vittorio; Khinast, Johannes G

2014-10-01

284

The Influence of Formulation and Manufacturing Process Parameters on the Characteristics of Lyophilized Orally Disintegrating Tablets  

PubMed Central

Gelatin is a principal excipient used as a binder in the formulation of lyophilized orally disintegrating tablets. The current study focuses on exploiting the physicochemical properties of gelatin by varying formulation parameters to determine their influence on orally disintegrating tablet (ODT) characteristics. Process parameters, namely pH and ionic strength of the formulations, and ball milling were investigated to observe their effects on excipient characteristics and tablet formation. The properties and characteristics of the formulations and tablets which were investigated included: glass transition temperature, wettability, porosity, mechanical properties, disintegration time, morphology of the internal structure of the freeze-dried tablets, and drug dissolution. The results from the pH study revealed that adjusting the pH of the formulation away from the isoelectric point of gelatin, resulted in an improvement in tablet disintegration time possibly due to increase in gelatin swelling resulting in greater tablet porosity. The results from the ionic strength study revealed that the inclusion of sodium chloride influenced tablet porosity, tablet morphology and the glass transition temperature of the formulations. Data from the milling study showed that milling the excipients influenced formulation characteristics, namely wettability and powder porosity. The study concludes that alterations of simple parameters such as pH and salt concentration have a significant influence on formulation of ODT. PMID:24310589

Jones, Rhys J.; Rajabi-Siahboomi, Ali; Levina, Marina; Perrie, Yvonne; Mohammed, Afzal R.

2011-01-01

285

Crack toughness evaluation of hot pressed and forged beryllium  

NASA Technical Reports Server (NTRS)

Beryllium fracture toughness test specimens were fatigue cracked using reversed cycling with a compression load two to three times the tension load. In worked beryllium, textures may be produced which result in fatigue cracks that are out of plane with the starter notch. Specimens of hot pressed stock exhibited load displacement records which were nonlinear throughout their course. Fracture specimens of both hot pressed and forged stock showed essentially no reduction of thickness and the fracture surfaces were flat and normal to the load axis. However, the stress intensity factor at maximum load increased with decreasing thickness. Load-displacement and electric potential records for the hot pressed beryllium specimens exhibited several anomalies such as negative residual crack mouth displacements and a decrease in electrical potential with increasing load.

Jones, M. H.; Bubsey, R. T.; Brown, W. F., Jr.

1971-01-01

286

Numerical study of the process parameters in spark plasma sintering (sps)  

NASA Astrophysics Data System (ADS)

Spark plasma sintering (SPS) is one of the most widely used sintering techniques that utilizes pulsed direct current together with uniaxial pressure to consolidate a wide variety of materials. The unique mechanisms of SPS enable it to sinter powder compacts at a lower temperature and in a shorter time than the conventional hot pressing, hot isostatic pressing and vacuum sintering process. One of the limitations of SPS is the presence of temperature gradients inside the sample, which could result in non-uniform physical and microstructural properties. Detailed study of the temperature and current distributions inside the sintered sample is necessary to minimize the temperature gradients and achieve desired properties. In the present study, a coupled thermal-electric model was developed using finite element codes in ABAQUS software to investigate the temperature and current distributions inside the conductive and non-conductive samples. An integrated experimental-numerical methodology was implemented to determine the system contact resistances accurately. The developed sintering model was validated by a series of experiments, which showed good agreements with simulation results. The temperature distribution inside the sample depends on some process parameters such as sample and tool geometry, punch and die position, applied current and thermal insulation around the die. The role of these parameters on sample temperature distribution was systematically analyzed. The findings of this research could prove very useful for the reliable production of large size sintered samples with controlled and tailored properties.

Chowdhury, Redwan Jahid

287

Deterministic flows of order-parameters in stochastic processes of quantum Monte Carlo method  

NASA Astrophysics Data System (ADS)

In terms of the stochastic process of quantum-mechanical version of Markov chain Monte Carlo method (the MCMC), we analytically derive macroscopically deterministic flow equations of order parameters such as spontaneous magnetization in infinite-range (d(= ?)-dimensional) quantum spin systems. By means of the Trotter decomposition, we consider the transition probability of Glauber-type dynamics of microscopic states for the corresponding (d + 1)-dimensional classical system. Under the static approximation, differential equations with respect to macroscopic order parameters are explicitly obtained from the master equation that describes the microscopic-law. In the steady state, we show that the equations are identical to the saddle point equations for the equilibrium state of the same system. The equation for the dynamical Ising model is recovered in the classical limit. We also check the validity of the static approximation by making use of computer simulations for finite size systems and discuss several possible extensions of our approach to disordered spin systems for statistical-mechanical informatics. Especially, we shall use our procedure to evaluate the decoding process of Bayesian image restoration. With the assistance of the concept of dynamical replica theory (the DRT), we derive the zero-temperature flow equation of image restoration measure showing some 'non-monotonic' behaviour in its time evolution.

Inoue, Jun-ichi

2010-06-01

288

Milling Process FEM Simulation for Identification of Material Parameters Directly from Experiments  

SciTech Connect

An identification procedure for the determination of material parameters that are used for the FEM simulation of milling processes is proposed. This procedure is based on the coupling of a numerical identification procedure and FEM simulations of milling operations. The experimental data result directly from measurements performed during milling experiments. A special device has been instrumented and calibrated to perform force and torque measurements, directly during machining experiments in using a piezoelectric dynamometer and a high frequency charge amplifier. The forces and torques are stored and low pass filtered if necessary, and these data provide the main basis for the identification procedure which is based on coupling 3D FEM simulations of milling and optimization/identification algorithms. The identification approach is mainly based on the Surfaces Response Method in the material parameters space, coupled to a sensitivity analysis. A Moving Least Square Approximation method is used to accelerate the identification process. The material behaviour is described from Johnson-Cook law. A fracture model is also added to consider chip formation and separation. The FEM simulations of milling are performed using explicit ALE based FEM code. The inverse identification method is here applied on a 304L stainless steel and the first results are presented.

Maurel, A.; Fontaine, M.; Thibaud, S.; Michel, G.; Gelin, J. C. [FEMTO-ST Institute / Applied Mechanics Laboratory, ENSMM, 26 rue de l'Epitaphe, 25000 Besancon (France)

2007-05-17

289

The role of interior watershed processes in improving parameter estimation and performance of watershed models.  

PubMed

Watershed models typically are evaluated solely through comparison of in-stream water and nutrient fluxes with measured data using established performance criteria, whereas processes and responses within the interior of the watershed that govern these global fluxes often are neglected. Due to the large number of parameters at the disposal of these models, circumstances may arise in which excellent global results are achieved using inaccurate magnitudes of these "intra-watershed" responses. When used for scenario analysis, a given model hence may inaccurately predict the global, in-stream effect of implementing land-use practices at the interior of the watershed. In this study, data regarding internal watershed behavior are used to constrain parameter estimation to maintain realistic intra-watershed responses while also matching available in-stream monitoring data. The methodology is demonstrated for the Eagle Creek Watershed in central Indiana. Streamflow and nitrate (NO) loading are used as global in-stream comparisons, with two process responses, the annual mass of denitrification and the ratio of NO losses from subsurface and surface flow, used to constrain parameter estimation. Results show that imposing these constraints not only yields realistic internal watershed behavior but also provides good in-stream comparisons. Results further demonstrate that in the absence of incorporating intra-watershed constraints, evaluation of nutrient abatement strategies could be misleading, even though typical performance criteria are satisfied. Incorporating intra-watershed responses yields a watershed model that more accurately represents the observed behavior of the system and hence a tool that can be used with confidence in scenario evaluation. PMID:25603246

Yen, Haw; Bailey, Ryan T; Arabi, Mazdak; Ahmadi, Mehdi; White, Michael J; Arnold, Jeffrey G

2014-09-01

290

Reducing PAH emissions from the iron ore sintering process by optimizing its operation parameters.  

PubMed

This study set out to reduce polycyclic aromatic hydrocarbon (PAH) emissions from the iron ore sintering process by optimizing its operation parameters obtained from the Taguchi experimental design. Four operating parameters, including the water content (Wc; range = 6.0-7.0 wt %), suction pressure (Ps; range = 1000-1400 mmH2O), bed height (Hb; range = 500-600 mm), and type of hearth layer (HL; including sinter, hematite, and limonite) were selected and conducted on a pilot-scale sinter pot to simulate various sintering operating conditions of a real-scale sinter plant. We found that the resultant optimal combination (Wc = 6.5 wt %, Hb = 600 mm, Ps = 1400 mmH2O, and HL = limonite) could reduce the emission factor of total BaP equivalent concentration (EF(BaPeq)) up to 57.6% in comparison with the current operating condition of a real-scale sinter plant (Wc = 6.5 wt %, Hb = 550 mm, Ps = 1200 mmH2O, and HL = sinter). Through the ANOVA analysis, we found that Ps and Hb were the top two parameters affecting total EF(BaPeq) (accounting, respectively, for 70.9% and 21.2% of the total contribution of the four selected parameters). By examining both the sinter productivity and sinter strength, the values obtained from the optimal combination were quite comparable to those of the current operating condition. The above results further confirm the applicability of the obtained optimal combination for the real-scale sinter plant. PMID:19603662

Chen, Yu-Cheng; Tsai, Perng-Jy; Mou, Jin-Luh

2009-06-15

291

Engine Performance of Precision-forged, Electropolished and Machined Blades of Nimonic 80 and 80A Alloys  

NASA Technical Reports Server (NTRS)

An investigation was conducted to determine the effect of electropolishing precision-forged blades and of machining blades from oversize forgings on the engine performance of Nimonic 80 and Nimonic 80A turbine blades. These blades, along with precision-forged blades, were run in a J33-9 turbojet engine. The tests resulted in the following conclusions: (1) Electropolishing of precision-forged blades did not improve engine life relative to the life of nonelectropolished blades. (2) Machining blades from oversize forgings did not improve the engine life of precision-forged blades. (3) The precision-forging and heat-treating practice used in fabricating the blades investigated was such that the surface roughness and oxide penetration was so slight, approximately 0.0005 inch in depth, as to preclude any benefits derived from surface removal by electropolishing or machining.

Sikora, Paul F; Johnston, James R

1955-01-01

292

Modeling and parameter identification of the simultaneous saccharification-fermentation process for ethanol production.  

PubMed

Despite many environmental advantages of using alcohol as a fuel, there are still serious questions about its economical feasibility when compared with oil-based fuels. The bioethanol industry needs to be more competitive, and therefore, all stages of its production process must be simple, inexpensive, efficient, and "easy" to control. In recent years, there have been significant improvements in process design, such as in the purification technologies for ethanol dehydration (molecular sieves, pressure swing adsorption, pervaporation, etc.) and in genetic modifications of microbial strains. However, a lot of research effort is still required in optimization and control, where the first step is the development of suitable models of the process, which can be used as a simulated plant, as a soft sensor or as part of the control algorithm. Thus, toward developing good, reliable, and simple but highly predictive models that can be used in the future for optimization and process control applications, in this paper an unstructured and a cybernetic model are proposed and compared for the simultaneous saccharification-fermentation process (SSF) for the production of ethanol from starch by a recombinant Saccharomyces cerevisiae strain. The cybernetic model proposed is a new one that considers the degradation of starch not only into glucose but also into dextrins (reducing sugars) and takes into account the intracellular reactions occurring inside the cells, giving a more detailed description of the process. Furthermore, an identification procedure based on the Metropolis Monte Carlo optimization method coupled with a sensitivity analysis is proposed for the identification of the model's parameters, employing experimental data reported in the literature. PMID:17935346

Ochoa, Silvia; Yoo, Ahrim; Repke, Jens-Uwe; Wozny, Günter; Yang, Dae Ryook

2007-01-01

293

Characterization of large 2219 aluminum alloy hand forgings for the space shuttle solid rocket booster  

NASA Technical Reports Server (NTRS)

The mechanical properties, including fracture toughness, and stress corrosion properties of four types of 2219-T852 aluminum alloy hand forgings are presented. Weight of the forgings varied between 450 and 3500 lb at the time of heat treatment and dimensions exceeded the maximum covered in existing specifications. The forgings were destructively tested to develop reliable mechanical property data to replace estimates employed in the design of the Space Shuttle Solid Rocket Booster (SRB) and to establish minimum guaranteed properties for structural refinement and for entry into specification revisions. The report summarizes data required from the forgers and from the SRB Structures contractor.

Brennecke, M. W.

1978-01-01

294

Effect of Electron Beam Freeform Fabrication (EBF3) Processing Parameters on Composition of Ti-6-4  

NASA Technical Reports Server (NTRS)

The Electron Beam Freeform Fabrication (EBF3) process developed at NASA Langley Research Center was evaluated using a design of experiments approach to determine the effect of processing parameters on the composition and geometry of Ti-6-4 deposits. The effects of three processing parameters: beam power, translation speed, and wire feed rate, were investigated by varying one while keeping the remaining parameters constant. A three-factorial, three-level, fully balanced mutually orthogonal array (L27) design of experiments approach was used to examine the effects of low, medium, and high settings for the processing parameters on the chemistry, geometry, and quality of the resulting deposits. Single bead high deposits were fabricated and evaluated for 27 experimental conditions. Loss of aluminum in Ti-6-4 was observed in EBF3 processing due to selective vaporization of the aluminum from the sustained molten pool in the vacuum environment; therefore, the chemistries of the deposits were measured and compared with the composition of the initial wire and base plate to determine if the loss of aluminum could be minimized through careful selection of processing parameters. The influence of processing parameters and coupling between these parameters on bulk composition, measured by Direct Current Plasma (DCP), local microchemistries determined by Wavelength Dispersive Spectrometry (WDS), and deposit geometry will also be discussed.

Lach, Cynthia L.; Taminger, Karen; Schuszler, A. Bud, II; Sankaran, Sankara; Ehlers, Helen; Nasserrafi, Rahbar; Woods, Bryan

2007-01-01

295

Effects of Process Parameters on Ultrasonic Micro-Hole Drilling in Glass and Ruby  

NASA Astrophysics Data System (ADS)

Brittle materials such as ceramics, glasses and oxide single crystals find increasing applications in advanced micro-engineering products. Machining small features in such materials represents a manufacturing challenge. Ultrasonic drilling constitutes a promising technique for realizing simple micro-holes of high diameter-to-depth ratio. The process involves impacting abrasive particles in suspension in a liquid slurry between tool and work piece. Among the process performance criteria, the drilling time (productivity) is one of the most important quantities to evaluate the suitability of the process for industrial applications. This paper summarizes recent results pertaining to the ultrasonic micro-drilling process obtained with a semi-industrial 3-axis machine. The workpiece is vibrated at 40 kHz frequency with an amplitude of several micrometers. A voice-coil actuator and a control loop based on the drilling force impose the tool feed. In addition, the tool is rotated at a prescribed speed to improve the drilling speed as well as the hole geometry. Typically, a WC wire serves as tool to bore 200 ?m diameter micro-holes of 300 to 1,000 ?m depth in glass and ruby. The abrasive slurry contains B4C particles of 1 ?m to 5 ?m diameter in various concentrations. This paper discusses, on the basis of the experimental results, the influence of several parameters on the drilling time. First, the results show that the control strategy based on the drilling force allows to reach higher feed rates (avoiding tool breakage). Typically, a 8 um/s feed rate is achieved with glass and 0.9 ?m/s with ruby. Tool rotation, even for values as low as 50 rpm, increases productivity and improves holes geometry. Drilling with 1 ?m and 5 ?m B4C particles yields similar productivity results. Our future research will focus on using the presented results to develop a model that can serve to optimize the process for different applications.

Schorderet, Alain; Deghilage, Emmanuel; Agbeviade, Kossi

2011-05-01

296

Model-based identifiable parameter determination applied to a simultaneous saccharification and fermentation process model for bio-ethanol production.  

PubMed

In this work, a methodology for the model-based identifiable parameter determination (MBIPD) is presented. This systematic approach is proposed to be used for structure and parameter identification of nonlinear models of biological reaction networks. Usually, this kind of problems are over-parameterized with large correlations between parameters. Hence, the related inverse problems for parameter determination and analysis are mathematically ill-posed and numerically difficult to solve. The proposed MBIPD methodology comprises several tasks: (i) model selection, (ii) tracking of an adequate initial guess, and (iii) an iterative parameter estimation step which includes an identifiable parameter subset selection (SsS) algorithm and accuracy analysis of the estimated parameters. The SsS algorithm is based on the analysis of the sensitivity matrix by rank revealing factorization methods. Using this, a reduction of the parameter search space to a reasonable subset, which can be reliably and efficiently estimated from available measurements, is achieved. The simultaneous saccharification and fermentation (SSF) process for bio-ethanol production from cellulosic material is used as case study for testing the methodology. The successful application of MBIPD to the SSF process demonstrates a relatively large reduction in the identified parameter space. It is shown by a cross-validation that using the identified parameters (even though the reduction of the search space), the model is still able to predict the experimental data properly. Moreover, it is shown that the model is easily and efficiently adapted to new process conditions by solving reduced and well conditioned problems. PMID:23749438

López C, Diana C; Barz, Tilman; Peñuela, Mariana; Villegas, Adriana; Ochoa, Silvia; Wozny, Günter

2013-01-01

297

Variation of thermal and mechanical properties of KMPR due to processing parameters  

NASA Astrophysics Data System (ADS)

We present a study of the thermal and mechanical properties of the negative photoresist KMPR and the influence of processing conditions on those properties. The process parameters chosen all relate to the cross-linking level of the photoresist: the UV exposure dose, the baking temperature and the bake length. The stability of KMPR at high temperatures was also examined. The glass transition temperature was measured using dynamic mechanical analysis, with a maximum measured value of 128 °C achieved in our tests. Relating the glass transition temperature to the cross-linking level of the material, exposure doses higher than 2 J cm-2 were shown to have a negligible effect on the cross-linking (for 80 ?m thick films). Using thermogravitmetric analysis, KMPR has been shown to lose significant mass when heated above 200 °C. Young's modulus of KMPR was measured to be between 2.0 GPa for samples hard-baked at 100 °C and 2.7 GPa for samples baked at 150 and 200 °C. Creep behavior for KMPR held under strain was studied for samples prepared under a range of processing temperatures. Finally the thermally-induced cross-linking of unexposed KMPR was studied, with samples post-exposure baked at 150 °C, or 120 °C for at least an hour, cross-linking sufficiently to prevent development.

Reynolds, Matthew; Elias, Anastasia; Elliott, Duncan G.; Backhouse, Christopher; Sameoto, Dan

2012-12-01

298

Property and microstructure evaluation as a function of processing parameters: Large HY-80 steel casting for a US Navy submarine  

Microsoft Academic Search

Processing techniques can significantly alter the properties of a material and can ultimately determine whether a component will perform its function safely. This effort involves the investigation of the processing parameters of HY-80 steel castings; specifically a large HY-80 submarine casting that failed while in service due to improper processing. Samples taken from the failed casting were evaluated in the

John E. Holthaus; Michelle G. Koul; Angela L. Moran

2006-01-01

299

Gaussian processes retrieval of leaf parameters from a multi-species reflectance, absorbance and fluorescence dataset.  

PubMed

Biochemical and structural leaf properties such as chlorophyll content (Chl), nitrogen content (N), leaf water content (LWC), and specific leaf area (SLA) have the benefit to be estimated through nondestructive spectral measurements. Current practices, however, mainly focus on a limited amount of wavelength bands while more information could be extracted from other wavelengths in the full range (400-2500nm) spectrum. In this research, leaf characteristics were estimated from a field-based multi-species dataset, covering a wide range in leaf structures and Chl concentrations. The dataset contains leaves with extremely high Chl concentrations (>100?gcm(-2)), which are seldom estimated. Parameter retrieval was conducted with the machine learning regression algorithm Gaussian Processes (GP), which is able to perform adaptive, nonlinear data fitting for complex datasets. Moreover, insight in relevant bands is provided during the development of a regression model. Consequently, the physical meaning of the model can be explored. Best estimates of SLA, LWC and Chl yielded a best obtained normalized root mean square error of 6.0%, 7.7%, 9.1%, respectively. Several distinct wavebands were chosen across the whole spectrum. A band in the red edge (710nm) appeared to be most important for the estimation of Chl. Interestingly, spectral features related to biochemicals with a structural or carbon storage function (e.g. 1090, 1550, 1670, 1730nm) were found important not only for estimation of SLA, but also for LWC, Chl or N estimation. Similar, Chl estimation was also helped by some wavebands related to water content (950, 1430nm) due to correlation between the parameters. It is shown that leaf parameter retrieval by GP regression is successful, and able to cope with large structural differences between leaves. PMID:24792473

Van Wittenberghe, Shari; Verrelst, Jochem; Rivera, Juan Pablo; Alonso, Luis; Moreno, José; Samson, Roeland

2014-05-01

300

Selection of process parameters for producing high quality defatted sesame flour at pilot scale.  

PubMed

The present work was undertaken to study the effect of pearling duration, soaking time, steaming duration and drying temperature on the quality of sesame seeds and mechanically extracted partially defatted sesame cake. On the basis of quality attributes i.e. high protein, low crude fibre, low residual oil and low oxalic acid, the optimum process parameters were selected. The combination of 20 min of pearling duration, 15 min of soaking, 15 min of steaming at 100 kPa pressure and drying at 50 °C yielded high quality partially defatted protein rich sesame flour as compared to untreated defatted sesame flour. The developed high quality partially defatted protein rich sesame flour may be used in various food applications as a vital ingredient to increase the nutritional significance of the prepared foodstuffs. PMID:25745256

Manikantan, M R; Sharma, Rajiv; Yadav, D N; Gupta, R K

2015-03-01

301

Optimization of Machining Process Parameters for Surface Roughness of Al-Composites  

NASA Astrophysics Data System (ADS)

Metal matrix composites (MMCs) have become a leading material among the various types of composite materials for different applications due to their excellent engineering properties. Among the various types of composites materials, aluminum MMCs have received considerable attention in automobile and aerospace applications. These materials are known as the difficult-to-machine materials because of the hardness and abrasive nature of reinforcement element-like silicon carbide particles. In the present investigation Al-SiC composite was produced by stir casting process. The Brinell hardness of the alloy after SiC addition had increased from 74 ± 2 to 95 ± 5 respectively. The composite was machined using CNC turning center under different machining parameters such as cutting speed (S), feed rate (F), depth of cut (D) and nose radius (R). The effect of machining parameters on surface roughness (Ra) was studied using response surface methodology. Face centered composite design with three levels of each factor was used for surface roughness study of the developed composite. A response surface model for surface roughness was developed in terms of main factors (S, F, D and R) and their significant interactions (SD, SR, FD and FR). The developed model was validated by conducting experiments under different conditions. Further the model was optimized for minimum surface roughness. An error of 3-7 % was observed in the modeled and experimental results. Further, it was fond that the surface roughness of Al-alloy at optimum conditions is lower than that of Al-SiC composite.

Sharma, S.

2013-10-01

302

Effect of Process Parameters on Friction Force and Material Removal in Oxide Chemical Mechanical Polishing  

NASA Astrophysics Data System (ADS)

The relationship between sliding friction and material removal was investigated using a sensor to measure dynamic friction force according to process parameters such as pressure, velocity, conditioning, abrasive concentration, and slurry pH during oxide chemical mechanical polishing (CMP). Friction force and material removal linearly depend on applied load and relative velocity. A high relative velocity also has an effect on the boundary condition between the wafer and the pad, and friction force reduces with increase in relative velocity. Friction force reduces with polishing time during oxide CMP with ex situ conditioning because of the changes in pad roughness parameters such as Ra, Rp, Rpk, and Rsk. Thus, the in situ conditioning method increases removal rate and improves nonuniformity. Friction force can be uniformly distributed on the oxide wafer as abrasive concentration increases owing to the reduction in friction force loaded on one abrasive particle, improving the nonuniformity of removal rate. In oxide CMP using alkali-based slurry, the effective formation and mechanical removal of the Si-OH bond layer on the SiO2 surface also affect the temporal decrease in friction force and result in a higher removal rate, in comparison with the results of a high friction force and a low removal rate in oxide CMP using neutral-based slurry.

Park, Boumyoung; Lee, Hyunseop; Kim, Youngjin; Kim, Hyoungjae; Jeong, Haedo

2008-12-01

303

Morphometric parameters of living human in-vitro fertilization embryos; importance of the asynchronous division process.  

PubMed

A total of 304 human pronuclear zygotes and cleaved embryos from the 2- to 9-cell stages, obtained during invitro fertilization attempts, were photographed and retrospectively analysed after transfer for their morphology and size in relation to their developmental stage, using the Imagenia programme of a Biocom 500 image analyser. Morphometric parameters were calculated from the perimeters, surface measurements, theoretical diameters and circularity factors for the different structures analysed. This report provides the morphometric characteristics of living embryos. For the whole population the mean values were: 157.4 microns for the external zona pellucida diameter, 121.8 microns for the internal zona pellucida diameter, 17.9 microns for the thickness of the zona pellucida and 117.2 microns for the embryo cell mass diameter. The morphometric characteristics of the pronuclear-stage population were significantly different from the cleaved cell stages. If the zona pellucida and cell mass embryo diameters increased slowly from the 2- to 9-cell stages, embryonic external diameters were higher and zona pellucida thicknesses were lower in odd than even number blastomere embryos. Preliminary results show that in cases where implantation occurs, the embryo has a lower zona pellucida thickness. A comparison of the different embryo cell stages confirmed the existence of an asynchronous division process during early embryo development. Global results show no evidence of morphometric differences between subpopulations of the embryos according to their microscopic grading. Deviations from the normal asynchronous division process, however, appear to be a new parameter to take into account during embryo scoring.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7657766

Roux, C; Joanne, C; Agnani, G; Fromm, M; Clavequin, M C; Bresson, J L

1995-05-01

304

Critical process parameters of an acetal-based deep-UV photoresist  

NASA Astrophysics Data System (ADS)

The present paper gives a first introduction into the resist scheme and the chemistry of a newly developed acetal-based, positive tone deep UV photoresist, called RS 1594/E. The material consists of a phenolic polymer, a dissolution inhibitor, and a photoactive compound. The dissolution inhibition of the polymer is achieved using a poly-N,O-acetal, which undergoes an efficient acid catalyzed bond cleavage. The radiation induced catalytic reaction starts at ambient temperatures and the latent image stabilizes in a dark reaction. The process is completed by the application of a post exposure bake resulting in the formation of highly soluble dissolution promoting fragments, namely aldehyde and alcohol derivatives. The properties of the main resist components have been studied in detail and their influence on the lithographic performance is discussed. In addition, new critical process parameters have been identified and their impact on the lithographic performance of RS 1594/E was analyzed. The dissolution rate ratio between exposed and unexposed resist areas, the post exposure bake temperature, and the delay time between exposure and post exposure bake were determined as the most significant parameters and are discussed in more detail. Prolonged intervals are found to be mainly responsible for the increased formation of an insoluble surface inhibition layer (`T-topping') and a significant linewidth decrease. Compared to state-of-the-art materials, RS 1594/E shows a noticeable improvement in delay time behavior. Even after 60 minutes delay between exposure and PEB acceptable results may be achieved without any formation of `T- shaped' profiles, and a nearly constant linewidth. The surface inhibition effect is markedly reduced by the use of certain organic additives and an optimized photoacid generator. SEM pictures of 0.24 micrometers , 0.26 micrometers , and 0.28 micrometers line and space patterns demonstrate the excellent resolution capability of RS 1594/E.

Roeschert, Horst; Przybilla, Klaus J.; Spiess, Walter; Wengenroth, Horst; Pawlowski, Georg

1992-06-01

305

Optimization of residual stresses in MMC's through the variation of interfacial layer architectures and processing parameters  

NASA Technical Reports Server (NTRS)

The objective of this work was the development of efficient, user-friendly computer codes for optimizing fabrication-induced residual stresses in metal matrix composites through the use of homogeneous and heterogeneous interfacial layer architectures and processing parameter variation. To satisfy this objective, three major computer codes have been developed and delivered to the NASA-Lewis Research Center, namely MCCM, OPTCOMP, and OPTCOMP2. MCCM is a general research-oriented code for investigating the effects of microstructural details, such as layered morphology of SCS-6 SiC fibers and multiple homogeneous interfacial layers, on the inelastic response of unidirectional metal matrix composites under axisymmetric thermomechanical loading. OPTCOMP and OPTCOMP2 combine the major analysis module resident in MCCM with a commercially-available optimization algorithm and are driven by user-friendly interfaces which facilitate input data construction and program execution. OPTCOMP enables the user to identify those dimensions, geometric arrangements and thermoelastoplastic properties of homogeneous interfacial layers that minimize thermal residual stresses for the specified set of constraints. OPTCOMP2 provides additional flexibility in the residual stress optimization through variation of the processing parameters (time, temperature, external pressure and axial load) as well as the microstructure of the interfacial region which is treated as a heterogeneous two-phase composite. Overviews of the capabilities of these codes are provided together with a summary of results that addresses the effects of various microstructural details of the fiber, interfacial layers and matrix region on the optimization of fabrication-induced residual stresses in metal matrix composites.

Pindera, Marek-Jerzy; Salzar, Robert S.

1996-01-01

306

Modifying welding process parameters can reduce the neurotoxic potential of manganese-containing welding fumes.  

PubMed

Welding fumes (WF) are a complex mixture of toxic metals and gases, inhalation of which can lead to adverse health effects among welders. The presence of manganese (Mn) in welding electrodes is cause for concern about the potential development of Parkinson's disease (PD)-like neurological disorder. Consequently, from an occupational safety perspective, there is a critical need to prevent adverse exposures to WF. As the fume generation rate and physicochemical characteristics of welding aerosols are influenced by welding process parameters like voltage, current or shielding gas, we sought to determine if changing such parameters can alter the fume profile and consequently its neurotoxic potential. Specifically, we evaluated the influence of voltage on fume composition and neurotoxic outcome. Rats were exposed by whole-body inhalation (40 mg/m(3); 3h/day × 5 d/week × 2 weeks) to fumes generated by gas-metal arc welding using stainless steel electrodes (GMA-SS) at standard/regular voltage (25 V; RVSS) or high voltage (30 V; HVSS). Fumes generated under these conditions exhibited similar particulate morphology, appearing as chain-like aggregates; however, HVSS fumes comprised of a larger fraction of ultrafine particulates that are generally considered to be more toxic than their fine counterparts. Paradoxically, exposure to HVSS fumes did not elicit dopaminergic neurotoxicity, as monitored by the expression of dopaminergic and PD-related markers. We show that the lack of neurotoxicity is due to reduced solubility of Mn in HVSS fumes. Our findings show promise for process control procedures in developing prevention strategies for Mn-related neurotoxicity during welding; however, it warrants additional investigations to determine if such modifications can be suitably adapted at the workplace to avert or reduce adverse neurological risks. PMID:25549921

Sriram, Krishnan; Lin, Gary X; Jefferson, Amy M; Stone, Samuel; Afshari, Aliakbar; Keane, Michael J; McKinney, Walter; Jackson, Mark; Chen, Bean T; Schwegler-Berry, Diane; Cumpston, Amy; Cumpston, Jared L; Roberts, Jenny R; Frazer, David G; Antonini, James M

2015-02-01

307

DataForge: A DDI-Enabled Toolkit for Researchers and Data Managers  

E-print Network

, and performing other useful operations around statistical datasets, to support data management, dissemination, or analysis activities. DataForge will initially be made available as desktop based products under both freeware and commercial licenses, with web based...

Gregory, Arofan; Heus, Pascal; Gager, J

2013-04-02

308

75 FR 70689 - Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum-Greenwood Forge Division; Currently...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Administration [TA-W-70,376] Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum- Greenwood Forge Division; Currently Known...2, 2009, applicable to workers of Kaiser Aluminum Fabricated Products, LLC, Kaiser...

2010-11-18

309

75 FR 20859 - Notice of Realty Action, Independence National Historical Park, Pennsylvania and Valley Forge...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Independence National Historical Park, Pennsylvania and Valley Forge National Historical Park, Pennsylvania AGENCY: National Park Service, Department...Federal land in Philadelphia County, Pennsylvania, for a 78- acre parcel of...

2010-04-21

310

The optimal cutting-parameter selection of heavy cutting process in side milling for SUS304 stainless steel  

Microsoft Academic Search

This paper presents an optimal cutting-parameter design of heavy cutting in side milling for SUS304 stainless steel. The orthogonal\\u000a array with grey-fuzzy logics isapplied to optimize the side milling process with multiple performance characteristics. A grey-fuzzy\\u000a reasoning grade obtained from the grey-fuzzylogics analysis is used as a performance index to determine the optimal cutting\\u000a parameters. The selected cutting parameters are

Chang Ching-Kao; H. S. Lu

2007-01-01

311

Numerical investigations on the fatigue failure of forging tools due to thermo-mechanical cyclic loading  

Microsoft Academic Search

During service hot forging dies are exposed to a combination of cyclic thermo-mechanical, tribological and chemical loads.\\u000a Besides abrasive and adhesive wear on the die surface, fatigue crack initiation with subsequent fracture is one of the most\\u000a frequent cause of failure. Fatigue cracks in forging dies are caused by local elasto-plastic strains due to cyclic mechanical\\u000a and thermal loads. Aiming

B.-A. Behrens; A. Bouguecha; H. W. Raedt; M. Sc. T. Hadifi

2010-01-01

312

Nine percent nickel steel heavy forging weld repair study. [National Transonic Wind Tunnel fan components  

NASA Technical Reports Server (NTRS)

The feasibility of making weld repairs on heavy section 9% nickel steel forgings such as those being manufactured for the National Transonic Facility fan disk and fan drive shaft components was evaluated. Results indicate that 9% nickel steel in heavy forgings has very good weldability characteristics for the particular weld rod and weld procedures used. A comparison of data for known similar work is included.

Young, C. P., Jr.; Gerringer, A. H.; Brooks, T. G.; Berry, R. F., Jr.

1978-01-01

313

An integrated approach to optimise parameter design of multi-response processes based on Taguchi method and artificial intelligence  

Microsoft Academic Search

The Taguchi robust parameter design has been widely used over the past decade to solve many single-response process parameter\\u000a designs. However, the Taguchi method is unable to deal with multi-response problems that are of main interest today, owing\\u000a to increasing complexity of manufacturing processes and products. Several recent studies have been conducted in order to solve\\u000a this problem. But, they

Tatjana V. Sibalija; Vidosav D. Majstorovic

314

Application of Taguchi optimization technique in determining plastic injection molding process parameters for a thin-shell part  

Microsoft Academic Search

This paper deals with the application of Taguchi optimization technique to reduce warpage problem related to the shrinkage variation depended on process parameters during production of thin-shell plastic components for orthose part. For this purpose, a number of MoldFlow analyses are carried out by utilizing the combination of process parameters based on three-level of L27 and L9 Taguchi orthogonal design.

Hasan Oktem; Tuncay Erzurumlu; Ibrahim Uzman

2007-01-01

315

* Corresponding author: Mines ParisTech, B. P. 207 -F-06 904 Sophia-Antipolis, France -jean-loup.chenot@ mines-paristech.fr FINITE ELEMENT MODELLING OF FORGING  

E-print Network

-Antipolis, France - jean-loup.chenot@ mines-paristech.fr FINITE ELEMENT MODELLING OF FORGING AND OTHER METAL FORMING____________________ * Corresponding author: Mines ParisTech, B. P. 207 - F-06 904 Sophia PROCESSES J-L Chenot1 *, L. Fourment1 , R. Ducloux2 and E. Wey2 . 1 CEMEF, Mines ParisTech and CNRS UMR7635

Boyer, Edmond

316

Mathematical Model of Solid Food Pasteurization by Ohmic Heating: Influence of Process Parameters  

PubMed Central

Pasteurization of a solid food undergoing ohmic heating has been analysed by means of a mathematical model, involving the simultaneous solution of Laplace's equation, which describes the distribution of electrical potential within a food, the heat transfer equation, using a source term involving the displacement of electrical potential, the kinetics of inactivation of microorganisms likely to be contaminating the product. In the model, thermophysical and electrical properties as function of temperature are used. Previous works have shown the occurrence of heat loss from food products to the external environment during ohmic heating. The current model predicts that, when temperature gradients are established in the proximity of the outer ohmic cell surface, more cold areas are present at junctions of electrodes with lateral sample surface. For these reasons, colder external shells are the critical areas to be monitored, instead of internal points (typically geometrical center) as in classical pure conductive heat transfer. Analysis is carried out in order to understand the influence of pasteurisation process parameters on this temperature distribution. A successful model helps to improve understanding of these processing phenomenon, which in turn will help to reduce the magnitude of the temperature differential within the product and ultimately provide a more uniformly pasteurized product. PMID:24574874

2014-01-01

317

Influence of the process parameters on the replication of microstructured freeform surfaces  

NASA Astrophysics Data System (ADS)

Surfaces of technical parts are getting more and more attention in terms of functionalization. By modification, additional functionality is given to the part, e.g. self-cleaning effect or antireflection behavior. Nowadays mainly flat surfaces are structured which is a consequence of the available production methods. However, the demand of micro structured free form surfaces is increasing, enabling novel products. A major problem in the mass production (e.g. injection molding) of structured freeform surfaces is to demold these structures without ripping or deforming them due to occurring undercuts. Recently a novel concept was developed which overcomes this limitation. A nickel substrate containing a structure composed of lines orientated in two different directions, one orientated in melt flow direction, the other one perpendicular to that, but both with a cross-section of approximately 45 ?m × 55 ?m (w × h) was used as a premaster to cast a flexible master. This master made of poly(dimethylsiloxane) (PDMS) was mounted on a bending edge in an injection mold cavity. Within this paper the influence of process parameters on the replication grade of the structure lines depending on the structure orientation was evaluated, varying the holding pressure, melt and mold temperature using statistical design of experiment methods. The replication grade was evaluated by characterizing the shape of the structure lines along the entire process chain, using an infinite focus system. The results show, that the melt temperature has the biggest influence on the dimensions of the structures, the mold temperature only a slight one.

Burgsteiner, M.; Müller, F.; Lucyshyn, T.; Kukla, C.; Holzer, C.

2014-05-01

318

Investigation of critical core formulation and process parameters for osmotic pump oral drug delivery.  

PubMed

Push-pull osmotic pump (PPOP) tablets of a practically insoluble model drug were developed and the effect of various formulation and process parameters on tablet performance was evaluated in order to identify critical factors. The formulation factors such as the viscosity grade of polyethylene oxide as the primary polymer as well as the level and location of osmogen within the bilayer tablets led to a difference in performance of osmotic tablets and hence should be critically evaluated in the design of such dosage forms. Modification of granulation process, i.e., the granulating liquid composition or drying method of granules, did not impact the drug release from the osmotic tablets at the evaluated scale of this study. The influence of varying dose and aqueous solubility of other model drugs (i.e., theophylline, acetaminophen, and verapamil HCl) on the developed PPOP template was also investigated. Results showed that irrespective of the perceived complexity of development and manufacturing of osmotic pumps, the osmotic tablets in this study demonstrated a robust and yet flexible platform in accommodating different types of drug candidates, regardless of solubility, for the dose levels below 25% w/w of the pull layer formulation. PMID:24222269

Missaghi, Shahrzad; Patel, Piyush; Farrell, Thomas P; Huatan, Hiep; Rajabi-Siahboomi, Ali R

2014-02-01

319

Topographic study of sputter-deposited film with different process parameters  

SciTech Connect

In this study, molecular dynamics simulation is employed to investigate the surface topography of thin films produced by the sputtering process for different parameters such as substrate temperature, incident energy, and incident angle. Interface width is used to quantify the quality of the deposited film. The Morse potential is used to model the atomic interaction between atoms. From the results of this study, it is found that for lower substrate temperature, lower incident energy, and larger incident angle, the growing film structure tends toward a three-dimensional columnar structure, and a rougher film is produced. Conversely, for higher substrate temperature, higher incident energy, and smaller incident angle, the growing film structure tends toward a two-dimensional (Frank{endash}van der Merwe) quasi-layer-by-layer structure, and a smoother film is produced. Finally, average surface kinetic energy is found to be an important factor in determining the surface properties produced in the process. Generally, the produced film is smoother when the average surface kinetic energy is larger. {copyright} 2001 American Institute of Physics.

Ju, Shin-Pon; Weng, Cheng-I; Chang, Jee-Gong; Hwang, Chi-Chuan

2001-06-15

320

Effects of Flux Precoating and Process Parameter on Welding Performance of Inconel 718 Alloy TIG Welds  

NASA Astrophysics Data System (ADS)

The purpose of this study is to investigate the effect of activating flux on the depth-to-width ratio (DWR) and hot cracking susceptibility of Inconel 718 alloy tungsten inert gas (TIG) welds. The Taguchi method is employed to investigate the welding parameters that affect the DWR of weld bead and to achieve optimal conditions in the TIG welds that are coated with activating flux in TIG (A-TIG) process. There are eight single-component fluxes used in the initial experiment to evaluate the penetration capability of A-TIG welds. The experimental results show that the Inconel 718 alloy welds precoated with 50% SiO2 and 50% MoO3 flux were provided with better welding performance such as DWR and hot cracking susceptibility. The experimental procedure of TIG welding process using mixed-component flux and optimal conditions not only produces a significant increase in DWR of weld bead, but also decreases the hot cracking susceptibility of Inconel 718 alloy welds.

Lin, Hsuan-Liang; Wu, Tong-Min; Cheng, Ching-Min

2014-01-01

321

Optimizing Vacuum Assisted Resin Transfer Moulding (VARTM) Processing Parameters to Improve Part Quality  

NASA Astrophysics Data System (ADS)

The Low Cost Composites (LCC) group at Carleton University is studying out-of-autoclave composite manufacturing processes such as Vacuum Assisted Resin Transfer Moulding (VARTM) and Closed Cavity Bag Moulding (CCBM). These processes are used to produce inexpensive and high performance components for the GeoSurv II, an Unmanned Aerial Vehicle (UAV) being developed at Carleton University. This research has focused on optimizing VARTM processing parameters to reduce the weight and improve the strength and surface finish of GeoSurv II composite components. A simulation was developed to model resin flow through in VARTM infusions and was used to simulate mould filling and resin emptying of the GeoSurv II inverted V-empennage and mission avionics hatch. The resin infusion schemes of these parts were designed to ensure full preform resin saturation, and minimize thickness variations. An experimental study of the effects of the presence of a corner on composite thickness, void content, and strength was conducted. It was found that inside corners result in local increases in thickness and void content due to poor preform compaction. A novel bagging technique was developed to improve corner compaction, and this technique was shown to reduce thickness variability and void content. The strength, void content, and thickness variation were found to be heavily dependent on corner radius, with corner radii greater than 6.4 mm displaying the greatest improvement in performance for the layups considered. The design of the empennage and hatch mould incorporated the results of this study to improve the quality of these components.

Polowick, Christopher

322

Power ultrasound-assisted cleaner leather dyeing technique: influence of process parameters.  

PubMed

The application of power ultrasound to leather processing has a significant role in the concept of "clean technology" for leather production. The effect of power ultrasound in leather dyeing has been compared with dyeing in the absence of ultrasound and conventional drumming. The power ultrasound source used in these experiments was ultrasonic cleaner (150 W and 33 kHz). The effect of various process parameters such as amount of dye offer, temperature, and type of dye has been experimentally found out. The effect of presonication of dye solution as well as leather has been studied. Experiments at ultrasonic bath temperature were carried out to find out the combined thermal as well as stirring effects of ultrasound. Dyeing in the presence of ultrasound affords about 37.5 (1.8 times) difference as increase in % dye exhaustion or about 50% decrease in the time required for dyeing compared to dyeing in the absence of ultrasound for 4% acid red dye. About 29 (1.55 times) increase in % dye exhaustion or 30% reduction in time required for dyeing was observed using ultrasound at stationary condition compared with conventional dynamic drumming conditions. The effect of ultrasound at constant temperature conditions with a control experiment has also been studied. The dye exhaustion increases as the temperature increases (30-60 degrees C) and better results are observed at higher temperature due to the use of ultrasound. Presonication of dye solution or crust leather prior to the dyeing process has no significant improvement in dye exhaustion, suggesting ultrasound effect is realized when it is applied during the dyeing process. The results indicate that 1697 and 1416 ppm of dye can be reduced in the spent liquor due to the use of ultrasound for acid red (for 100 min) and acid black (for 3 h) dyes, respectively, thereby reducing the pollution load in the effluent stream. The color yield of the leather as inferred from the reflectance measurement indicates that dye offer can be halved when ultrasound is employed to promote dyeing. Scanning electron microscopy analysis of the cross section of the dyed leather indicates that fiber structure is not affected due to the use of ultrasound under the given process conditions. The present study clearly demonstrates that ultrasound can be used as a tool to improve the rate of exhaustion of dye, reduce pollution load in the spent effluent liquor, and improve the quality of leather produced. The study also offered provision to employ optimum levels of chemicals and increases percentage exhaustion for a given time, thereby limiting the pollution load in the tannery effluent, which is of great social concern. PMID:15046369

Sivakumar, Venkatasubramanian; Rao, Paruchuri Gangadhar

2004-03-01

323

Estimating seismic-source rate parameters associated with incomplete catalogues and superimposed Poisson-renewal generating processes  

NASA Astrophysics Data System (ADS)

A probabilistic model is presented to quantify parameters that define the exceedance rates of earthquake magnitudes. Incompleteness of seismic catalogues and superposition of Poisson-renewal earthquake generation processes are both taken into account within a Bayesian framework. The formulation can be transformed into the parameter estimation of single Poisson or renewal process. The incomplete exceedance rate parameters are estimated from incomplete data, so that the estimated values are equal to those of the complete rate. Two cases are studied: the first one corresponds to a seismic source in the Gulf of Mexico and the other to a seismic source in the southern Pacific coast of Mexico.

Alamilla, Jorge L.; Vai, Rossana; Esteva, Luis

2015-01-01

324

Hot forging of graphite-carbide composites. Final report  

SciTech Connect

This project was aimed at hot shaping of titanium carbide/graphite and vanadium carbide/graphite composite materials by heating them to above 2000 degrees celsius and pressing into an electrographite die. The sample was to be a preformed cylinder of powdered graphite mixed with powdered titanium or vanadium, lightly sintered. The preform would be heated in a hot press and the titanium or vanadium would react with some of the graphite to form titanium or vanadium carbide. The remaining (excess) graphite would form a composite with the carbide, and this could then be deformed plastically at temperatures well below the onset of plasticity in pure graphite. There were to be two major thrusts in the research: In the first, an electron beam furnace at Sandia Laboratory was to be used for rapid heating of the sample, which would then be transferred into the press. The second thrust was to be entirely at Alabama A and M University, and here they intended to use a heated, controlled atmosphere press to forge the graphite/carbide preforms at a steady temperature and measure their viscosity as a function of temperature. This report discusses the progress made on this project.

Jenkins, G.M.; Holland, L.R.

1998-07-15

325

NOVEL VAPOR-DEPOSITED LUBRICANTS FOR METAL-FORMING PROCESSES  

EPA Science Inventory

The report gives results of a preliminary laboratory study of the feasibility of using vapor-phase lubrication to lubricate industrial metal forging dies. (NOTE: the forging and shaping of metal parts is one of many metal fabricating processes that may generate volatile organic c...

326

Determining the kinematic parameters of a moving imaging sensor by processing spatial and temporal intensity changes  

Microsoft Academic Search

A method for the determination of the instantaneous kinematic parameters of an image-forming sensor moving relative to an optically structured environment was developed. The parameters are the roll, pitch and yaw rate, the angle of attack and yaw, and the orientation relative to a surface. Constraint equations between the intensity changes and the motion parameters were derived. Linear solutions of

Helmut Zinner

1986-01-01

327

Comparison of pitting fatigue life of ausforged and standard forged AISI M-50 and AISI 9310 spur gears  

NASA Technical Reports Server (NTRS)

Standard forged and ausforged spur gears made of vacuum-induction-melted, consumable-electrode, vacuum-arc-remelted AISI M-50 steel were tested under conditions that produced fatigue pitting. The gears were 8.89 cm (3.5 in.) in pitch diameter and had tip relief. The M-50 standard forged and ausforged test results were compared with each other. They were then compared with results for machined vacuum-arc-remelted AISI 9310 gears tested under identical conditions. Both types of M-50 gears had lives approximately five times that of the 9310 gears. The life at which 10 percent of the M-50 ausforged gears failed was slightly less than that at which the M-50 standard forged gears failed. The ausforged gears had a slightly greater tendency to fail by tooth fracture than did the standard forged gears, most likely because of the better forging and grain flow pattern of standard forged gears.

Townsend, D. P.; Bamberger, E. N.; Zaretsky, E. V.

1975-01-01

328

Impacts of High-Pressure Diecasting Process Parameters on Greenhouse Gas Emissions  

NASA Astrophysics Data System (ADS)

The impacts of some high-pressure diecasting (HPDC) process parameters on greenhouse gas (GHG) emissions are quantified using life cycle analysis (LCA) for both aluminum and magnesium alloys. The study was conducted according to ISO 14040 standards and was based on an automotive component made on cold-chamber HPDC machines operating in typical mass production environments. The aluminum alloy foundry was located in Australia; the magnesium alloy foundry was located in the United States. In both cases, emissions were found to reduce with an increasing HPDC process yield. However, yield variations had only a modest impact on GHG emissions in the aluminum alloy HPDC, due to the excellent in-plant recycling of the alloy and the relatively low emissions from primary aluminum production compared with primary magnesium production. In contrast, for the magnesium alloy, significant reductions in emissions were recorded as the yield increased. This outcome was attributed to the considerable savings achieved in raw material quantities sourced from high-emitting primary production and the use of lower amounts of SF6, a GHG with a very high global warming potential (GWP). These results were found to hold irrespective of changes to the ratio between the primary and secondary alloys in the raw material mix, although the magnitude of the impact was reduced considerably with reductions in the primary alloy component. In the case of the magnesium alloy HPDC, decreases in quality assurance (QA) rejects and cycle times were also found to contribute toward reduced emissions, although their influences were an order of magnitude lower than that of the yield improvements.

Gunasegaram, D. R.; Tharumarajah, A.

2009-08-01

329

Predicting final product properties of melt extruded solid dispersions from process parameters using Raman spectrometry.  

PubMed

Raman spectrometry was utilized to estimate degraded drug percentage, residual drug crystallinity and glass-transition temperature in the case of melt-extruded pharmaceutical products. Tight correlation was shown between the results obtained by confocal Raman mapping and transmission Raman spectrometry, a PAT-compatible potential in-line analytical tool. Immediate-release spironolactone-Eudragit E solid dispersions were the model system, owing to the achievable amorphization and the heat-sensitivity of the drug compound. The deep investigation of the relationship between process parameters, residual drug crystallinity and degradation was performed using statistical tools and a factorial experimental design defining 54 different circumstances for the preparation of solid dispersions. From the examined factors, drug content (10, 20 and 30%), temperature (110, 130 and 150°C) and residence time (2.75, 11.00 and 24.75min) were found to have significant and considerable effect. By forming physically stable homogeneous dispersions, the originally very slow dissolution of the lipophilic and poorly water-soluble spironolactone was reasonably improved, making 3minute release possible in acidic medium. PMID:24929869

Vigh, Tamás; Drávavölgyi, Gábor; Sóti, Péter L; Pataki, Hajnalka; Igricz, Tamás; Wagner, István; Vajna, Balázs; Madarász, János; Marosi, György; Nagy, Zsombor K

2014-09-01

330

Process parameter effects on material removal in magnetorheological finishing of borosilicate glass.  

PubMed

We investigate the effects of processing parameters on material removal for borosilicate glass. Data are collected on a magnetorheological finishing (MRF) spot taking machine (STM) with a standard aqueous magnetorheological (MR) fluid. Normal and shear forces are measured simultaneously, in situ, with a dynamic dual load cell. Shear stress is found to be independent of nanodiamond concentration, penetration depth, magnetic field strength, and the relative velocity between the part and the rotating MR fluid ribbon. Shear stress, determined primarily by the material mechanical properties, dominates removal in MRF. The addition of nanodiamond abrasives greatly enhances the material removal efficiency, with the removal rate saturating at a high abrasive concentration. The volumetric removal rate (VRR) increases with penetration depth but is insensitive to magnetic field strength. The VRR is strongly correlated with the relative velocity between the ribbon and the part, as expected by the Preston equation. A modified removal rate model for MRF offers a better estimation of MRF removal capability by including nanodiamond concentration and penetration depth. PMID:20357881

Miao, Chunlin; Lambropoulos, John C; Jacobs, Stephen D

2010-04-01

331

Influence of processing parameters on disintegration of Chlorella cells in various types of homogenizers.  

PubMed

The following bead mills used for disruption of the microalga Chlorella cells were tested: (1) Dyno-Mill ECM-Pilot, grinding chamber volume 1.5 L; KDL-Pilot A, chamber volume 1.4 L; KD 20 S, chamber volume 18.3 L; KD 25 S, chamber volume 26 L of Willy A. Bachofen, Basel, Switzerland, (2) LabStar LS 1, chamber volume 0.6 L of Netzsch, Selb, Germany, (3) MS 18, chamber volume 1.1 L of FrymaKoruma, Neuenburg, Germany. Amount of disrupted cells decreased with increasing Chlorella suspension feed rate and increased up to about 85% of the beads volume in the grinding chamber of the homogenizers. It also increased with agitator speed and number of passes of the algae suspension through the chamber. The optimum beads diameter was 0.3-0.5 mm in the homogenizers Dyno-Mill and LabStar LS 1 and 0.5-0.7 mm in the homogenizer MS 18. While the degree of the cell disruption decreased with increasing cell density in Dyno-Mill and LabStar, the cell disruption in the MS 18 increased. Depending on processing parameters, more than 90% of algae cells were disrupted by passing through the bead mills and bacteria count in algae suspension was reduced to about two orders. PMID:18758766

Doucha, J; Lívanský, K

2008-12-01

332

Analysis of the non-Markov parameter in continuous-time signal processing  

NASA Astrophysics Data System (ADS)

The use of statistical complexity metrics has yielded a number of successful methodologies to differentiate and identify signals from complex systems where the underlying dynamics cannot be calculated. The Mori-Zwanzig framework from statistical mechanics forms the basis for the generalized non-Markov parameter (NMP). The NMP has been used to successfully analyze signals in a diverse set of complex systems. In this paper we show that the Mori-Zwanzig framework masks an elegantly simple closed form of the first NMP, which, for C1 smooth autocorrelation functions, is solely a function of the second moment (spread) and amplitude envelope of the measured power spectrum. We then show that the higher-order NMPs can be constructed in closed form in a modular fashion from the lower-order NMPs. These results provide an alternative, signal processing-based perspective to analyze the NMP, which does not require an understanding of the Mori-Zwanzig generating equations. We analyze the parametric sensitivity of the zero-frequency value of the first NMP, which has been used as a metric to discriminate between states in complex systems. Specifically, we develop closed-form expressions for three instructive systems: band-limited white noise, the output of white noise input to an idealized all-pole filter,f and a simple harmonic oscillator driven by white noise. Analysis of these systems shows a primary sensitivity to the decay rate of the tail of the power spectrum.

Varghese, J. J.; Bellette, P. A.; Weegink, K. J.; Bradley, A. P.; Meehan, P. A.

2014-02-01

333

Method of validating measurement data of a process parameter from a plurality of individual sensor inputs  

DOEpatents

A method for generating a validated measurement of a process parameter at a point in time by using a plurality of individual sensor inputs from a scan of said sensors at said point in time. The sensor inputs from said scan are stored and a first validation pass is initiated by computing an initial average of all stored sensor inputs. Each sensor input is deviation checked by comparing each input including a preset tolerance against the initial average input. If the first deviation check is unsatisfactory, the sensor which produced the unsatisfactory input is flagged as suspect. It is then determined whether at least two of the inputs have not been flagged as suspect and are therefore considered good inputs. If two or more inputs are good, a second validation pass is initiated by computing a second average of all the good sensor inputs, and deviation checking the good inputs by comparing each good input including a present tolerance against the second average. If the second deviation check is satisfactory, the second average is displayed as the validated measurement and the suspect sensor as flagged as bad. A validation fault occurs if at least two inputs are not considered good, or if the second deviation check is not satisfactory. In the latter situation the inputs from each of all the sensors are compared against the last validated measurement and the value from the sensor input that deviates the least from the last valid measurement is displayed.

Scarola, Kenneth (Windsor, CT); Jamison, David S. (Windsor, CT); Manazir, Richard M. (North Canton, CT); Rescorl, Robert L. (Vernon, CT); Harmon, Daryl L. (Enfield, CT)

1998-01-01

334

Optimization of processing parameters for the analysis and detection of embolic signals.  

PubMed

The fast Fourier transform (FFT), which is employed by all commercially available ultrasonic systems, provides a time-frequency representation of Doppler ultrasonic signals obtained from blood flow. The FFT assumes that the signal is stationary within the analysis window. However, the presence of short duration embolic signals invalidates this assumption. For optimal detection of embolic signals if FFT is used for signal processing, it is important that the FFT parameters such as window size, window type, and required overlap ratio should be optimized. The effect of varying window type, window size and window overlap ratio were investigated for both simulated embolic signals, and recorded from patients with carotid artery stenosis. An optimal compromise is the use of a Hamming or Hanning window with a FFT size of 64 (8.9 ms) or 128 (17.9 ms). A high overlap ratio should also be employed in order not to miss embolic events occurring at the edges of analysis windows. The degree of overlap required will depend on the FFT size. The minimum overlap should be 65% for a 64-point window and 80% for a 128-point window. PMID:10996772

Aydin, N; Markus, H S

2000-09-01

335

Optimization and mechanical accuracy reliability of a new type of forging manipulator  

NASA Astrophysics Data System (ADS)

Researches on forging manipulator have enormous influence on the development of the forging industry and national economy. Clamp device and lifting mechanism are the core parts of forging manipulator, and have been studied for longer time. However, the optimization and mechanical accuracy reliability of them are less analyzed. Based on General Function( G F) set and parallel mechanism theory, proper configuration of 10t forging manipulator is selected firstly. A new type of forging manipulator driven by cylinders is proposed. After solved mechanical analysis of manipulator's core mechanisms, expressions of force of cylinders are carried out. In order to achieve smaller force afforded by cylinders and better mechanical characteristics, some particular sizes of core mechanisms are optimized intuitively through the combined use of the genetic algorithms(GA) and GUI interface in MATLAB. Comparing with the original mechanisms, optimized clamp saves at least 8 percent efforts and optimized lifting mechanism 20 percent under maximum working condition. Finally, considering the existed manufacture error of components, mechanical accuracy reliability of optimized clamp, lifting mechanism and whole manipulator are demonstrated respectively based on fuzzy reliability theory. Obtained results show that the accuracy reliability of optimized clamp is bigger than 0.991 and that of optimized lifting mechanism is 0.995. To the whole manipulator under maximum working condition, that value exceeds 0.986 4, which means that optimized manipulator has high motion accuracy and is reliable. A new intuitive method is created to optimize forging manipulator sizes efficiently and more practical theory is utilized to analyze mechanical accuracy reliability of forging manipulator precisely.

Chen, Kang; Ma, Chunxiang; Zheng, Maoqi; Gao, Feng

2015-03-01

336

Identification for the optimal working parameters of Al–Zn–Mg–Cu alloy with the processing maps based on DMM  

Microsoft Academic Search

As an important parameter in metal forming process, workability can be evaluated by means of processing maps on the basis\\u000a of dynamic material model, which are constructed from experimentally generated stress variation with respect to strain, strain\\u000a rate, and temperature. To obtain the processing map, hot compression tests were performed over a range of temperatures 573?723 K\\u000a and strain rates 0.01?10 s?1.

Guo-Zheng Quan; Beom-Soo Kang; Tae-Wan Ku; Woo-Jin Song

337

Evaluation and Optimization Method of High Speed Cutting Parameters Based on Cutting Process Simulation  

Microsoft Academic Search

The choice of reasonable cutting parameters is very important for the application of high speed cutting technology. Cutting\\u000a parameters optimization is a contradiction optimization problem of multi-objectives including cutting efficiency, tool wear\\u000a and machining quality etc. In order to simplify the complicated problem, a new dimensionless comprehensive evaluation method\\u000a of cutting parameters based on cutting multi-dimension characteristics including cutting force,

Zhijun Wu; Daochun Xu; Pingfa Feng; Dingwen Yu; Chenglong Zhang

2009-01-01

338

Forging School-Scientist Partnerships: A Case of Easier Said than Done?  

NASA Astrophysics Data System (ADS)

Since the early 1980s, a number of initiatives have been undertaken worldwide which have involved scientists and teachers working together in projects designed to support the science learning of students. Many of these have attempted to establish school-scientist partnerships. In these, scientists, teachers, and students formed teams engaged in mutually beneficial science-based activities founded on principles such as equal recognition and input, and shared vision, responsibility and risk. This article uses two partnership programmes run by a New Zealand Science Research Institute, to illustrate the challenges faced by scientists and teachers as they attempted to forge meaningful and effective partnerships. It argues that achieving the theorised position of a shared partnership space at the intersection of the worlds of scientists and teachers is problematic, and that scientists must instead be prepared to penetrate deeply into the world of the classroom when undertaking any such interactions. Findings indicate epistemological differences, curriculum and school systems and issues, and teacher efficacy and science knowledge significantly affect the process of partnership formation. Furthermore, it is argued that a re-thinking of partnerships is needed to reflect present economic and education environments, which are very different to those in which they were originally conceived nearly 30 years ago. It suggests that technology has an important role to play in future partnership interactions.

Falloon, Garry

2013-12-01

339

Forging Hispanic communities in new destinations: A case study of Durham, NC1  

PubMed Central

The Chicago School of urban sociology and its extension in the spatial assimilation model have provided the dominant framework for understanding the interplay between immigrant social and spatial mobility. However, the main tenets of the theory were derived from the experience of pre-war, centralized cities; scholars falling under the umbrella of the Los Angeles school have recently challenged the extent to which they are applicable to the contemporary urban form, which is characterized by sprawling, decentralized, and multi-nucleated development. Indeed, new immigrant destinations, such as those scattered throughout the American Southeast, are both decentralized and lack prior experience with large scale immigration. Informed by this debate this paper traces the formation and early evolution of Hispanic neighborhoods in Durham, NC, a new immigrant destination. Using qualitative data we construct a social history of immigrant neighborhoods and apply survey and census information to examine the spatial pattern of neighborhood succession. We also model the sorting of immigrants across neighborhoods according to personal characteristics. Despite the many differences in urban form and experience with immigration, the main processes forging the early development of Hispanic neighborhoods in Durham are remarkably consistent with the spatial expectations from the Chicago School, though the sorting of immigrants across neighborhoods is more closely connected to family dynamics and political economy considerations than purely human capital attributes. PMID:24482612

Flippen, Chenoa A.; Parrado, Emilio A.

2013-01-01

340

Optimum Process Parameters for the Treatment of Landfill Leachate Using Powdered Activated Carbon Augmented Sequencing Batch Reactor (SBR) Technology  

Microsoft Academic Search

The sequencing batch reactor (SBR) process was used for the treatment of raw landfill leachate. Optimum preliminary parameters of leachate\\/activated sludge ratio, powdered activated carbon (PAC) dosage, and settling time were studied. Optimum obtained parameters (mixing ratio of 10%, PAC dosage of 10 g\\/L, and settling time of 1.5 h) were applied on two types of SBRs, namely, non-powdered and powdered activated

Shuokr Qarani Aziz; Hamidi Abdul Aziz; Mohd Suffian Yusoff

2011-01-01

341

Parametric appraisal of process parameters for adhesion of plasma sprayed nanostructured YSZ coatings using Taguchi experimental design.  

PubMed

This paper presents the application of the Taguchi experimental design in developing nanostructured yittria stabilized zirconia (YSZ) coatings by plasma spraying process. This paper depicts dependence of adhesion strength of as-sprayed nanostructured YSZ coatings on various process parameters, and effect of those process parameters on performance output has been studied using Taguchi's L16 orthogonal array design. Particle velocities prior to impacting the substrate, stand-off-distance, and particle temperature are found to be the most significant parameter affecting the bond strength. To achieve retention of nanostructure, molten state of nanoagglomerates (temperature and velocity) has been monitored using particle diagnostics tool. Maximum adhesion strength of 40.56 MPa has been experimentally found out by selecting optimum levels of selected factors. The enhanced bond strength of nano-YSZ coating may be attributed to higher interfacial toughness due to cracks being interrupted by adherent nanozones. PMID:24288490

Mantry, Sisir; Mishra, Barada K; Chakraborty, Madhusudan

2013-01-01

342

Parametric Appraisal of Process Parameters for Adhesion of Plasma Sprayed Nanostructured YSZ Coatings Using Taguchi Experimental Design  

PubMed Central

This paper presents the application of the Taguchi experimental design in developing nanostructured yittria stabilized zirconia (YSZ) coatings by plasma spraying process. This paper depicts dependence of adhesion strength of as-sprayed nanostructured YSZ coatings on various process parameters, and effect of those process parameters on performance output has been studied using Taguchi's L16 orthogonal array design. Particle velocities prior to impacting the substrate, stand-off-distance, and particle temperature are found to be the most significant parameter affecting the bond strength. To achieve retention of nanostructure, molten state of nanoagglomerates (temperature and velocity) has been monitored using particle diagnostics tool. Maximum adhesion strength of 40.56?MPa has been experimentally found out by selecting optimum levels of selected factors. The enhanced bond strength of nano-YSZ coating may be attributed to higher interfacial toughness due to cracks being interrupted by adherent nanozones. PMID:24288490

Mantry, Sisir; Mishra, Barada K.; Chakraborty, Madhusudan

2013-01-01

343

Development of Processing Parameters for Organic Binders Using Selective Laser Sintering  

NASA Technical Reports Server (NTRS)

This document describes rapid prototyping, its relation to Computer Aided Design (CAD), and the application of these techniques to choosing parameters for Selective Laser Sintering (SLS). The document reviews the parameters selected by its author for his project, the SLS machine used, and its software.

Mobasher, Amir A.

2003-01-01

344

A simulation-based design parameter study in the stamping process of an automotive member  

Microsoft Academic Search

This paper is concerned with the quantitative effect of design parameters on a stamped part of the autobody. The considered parameters in this paper are the blank holding force, the draw-bead force and the blank size, which greatly affect the metal flow during stamping. The indicators of formability selected in this paper are failures such as tearing, wrinkling and the

Jung-Han Song; Hoon Huh; Se-Ho Kim

2007-01-01

345

TDNiCr (ni-20Cr-2ThO2) forging studies  

NASA Technical Reports Server (NTRS)

Elevated temperature tensile and stress rupture properties were evaluated for forged TDNiCr (Ni-20Cr-2ThO2) and related to thermomechanical history and microstructure. Forging temperature and final annealed condition had pronounced influences on grain size which, in turn, was related to high temperature strength. Tensile strength improved by a factor of 8 as grain size changed from 1 to 150 microns. Stress-rupture strength was improved by a factor of 3 to 5 by a grain size increase from 10 to 1000 microns. Some contributions to the elevated temperature strength of very large grain material may also occur from the development of a strong texture and a preponderance of small twins. Other conditions promoting the improvement of high temperature strength were: an increase of total reduction, forging which continued the metal deformation inherent in the starting material, a low forging speed, and prior deformation by extrusion. The mechanical properties of optimally forged TDNiCr compared favorably to those of high strength sheet developed for space shuttle application.

Filippi, A. M.

1974-01-01

346

Determining the kinematic parameters of a moving imaging sensor by processing spatial and temporal intensity changes  

NASA Astrophysics Data System (ADS)

A method for the determination of the instantaneous kinematic parameters of an image-forming sensor moving relative to an optically structured environment was developed. The parameters are the roll, pitch and yaw rate, the angle of attack and yaw, and the orientation relative to a surface. Constraint equations between the intensity changes and the motion parameters were derived. Linear solutions of these equations are the pure parameters, which are nonlinear functions of the motion parameters. The latter were obtained analytically by solving a 3x3 eigenvalue problem. An algorithm was implemented, and its accuracy and robustness were tested with various artificial and natural image sequences. The method proves to be robust and accurate enough for robot navigation. Flight simulations of an airborne vehicle show that this system can replace inertial as well as ranging systems.

Zinner, Helmut

347

Identification of Friction Parameters from the Inverse Analysis of a Direct Extrusion Test  

SciTech Connect

This work proposes to use a special upsetting test and an optimal direct extrusion one performed to identify the constitutive equation of the material behavior and the friction coefficients directly from the load-stroke curves. The proposed friction test has the advantage to permit to take into account contact phenomena corresponding to new specimen surfaces created during a real bulk cold forming process. A lot of numerical simulations are made with the commercial software FORGE2 in order to study the influence of some design and process parameters. Different friction laws will be identified starting from the classical Coulomb and Tresca ones. All the parameter identifications are made using the Inverse Analysis principle.

Adinel, Gavrus; Thien, Pham Duc [LGCGM Laboratory, EA 3913, INSA de RENNES, UEB, CS70839, F-35708, Rennes-Cedex 7 (France); Henri, Francillette [SCR/CM, UMR 6226, INSA de RENNES, UEB, CS70839, F-35708, Rennes-Cedex 7 (France)

2011-01-17

348

Processing of thermal parameters for the assessment of geothermal potential of sedimentary basins  

NASA Astrophysics Data System (ADS)

The growing interest on renewable energy sources is stimulating new efforts aimed at the assessment of geothermal potential in several countries, and new developments are expected in the near future. In this framework, a basic step forward is to focus geothermal investigations on geological environments which so far have been relatively neglected. Some intracontinental sedimentary basins could reveal important low enthalpy resources. The evaluation of the geothermal potential in such geological contexts involves the synergic use of geophysical and hydrogeological methodologies. In sedimentary basins a large amount of thermal and hydraulic data is generally available from petroleum wells. Unfortunately, borehole temperature data are often affected by a number of perturbations which make very difficult determination of the true geothermal gradient. In this paper we addressed the importance of the acquisition of thermal parameters (temperature, geothermal gradient, thermal properties of the rock) and the technical processing which is necessary to obtain reliable geothermal characterizations. In particular, techniques for corrections of bottom-hole temperature (BHT) data were reviewed. The objective was to create a working formula usable for computing the undisturbed formation temperature for specific sedimentary basins. As test areas, we analysed the sedimentary basins of northern Italy. Two classical techniques for processing temperature data from oil wells are customarily used: (i) the method by Horner, that requires two or more measurements of bottom-hole temperatures carried out at the same depth but at different shut-in times te and (ii) the technique by Cooper and Jones, in which several physical parameters of the mud and formation need to be known. We applied both methods to data from a number of petroleum explorative wells located in two areas of the Po Plain (Apenninic buried arc and South Piedmont Basin - Pedealpine homocline). From a set of about 40 wells having two or more temperature measurements at a single depth we selected 18 wells with BHTs recorded at te larger than 3.5 hours; the time span between two measurements varies from 1 to 21 hours. In total 71 couples of BHT-te data are available; the mud circulation time is lower or equal to 4.5 hours. Corrections require the knowledge of thermal parameters. We attempted to remedy the existing deficiency of thermal conductivity data of sedimentary rocks with a series of laboratory measurements on several core samples recovered from wells. Moreover, we developed a model for calculating the thermal conductivity of the rock matrix as a function of mineral composition based on the fabric theory and experimental thermal conductivity data. As the conductivity of clay minerals, which are present in most formations, is poorly defined, we applied an inverse approach, in which mineral conductivities are calculated one by one, on condition that the sample bulk thermal conductivity, the porosity and the amount of each mineral phase are known. Analyses show that formation equilibrium temperatures computed with the Horner method are consistent with those obtained by means of the Cooper and Jones method, which gives on average temperatures lower than 2 C only for shut-in times < 10 hours. The corrected temperatures compared with temperatures measured during drill-stem tests show that the proposed corrections are rather accurate. The two data sets give coherent results and the inferred average geothermal gradient is 21.5 mK/m in the Apenninic buried arc area and 25.2 mK/m in the South Piedmont Basin-Pedealpine homocline area. The problem with the Horner method is that it implicitly assumes no physical property contrast between circulating mud and formation, and that the borehole is infinitesimally thin, i.e. it acts as a line source. This has been criticized by many authors. The accuracy of the predicted temperatures depends on the reliability and accuracy of BHT, shut-in time and mud circulation time, and the error increases with the decrease of the shut-in time. On the ot

Pasquale, V.; Chiozzi, P.; Gola, G.; Verdoya, M.

2009-04-01

349

Modeling the X-ray Process, and X-ray Flaw Size Parameter for POD Studies  

NASA Technical Reports Server (NTRS)

Nondestructive evaluation (NDE) method reliability can be determined by a statistical flaw detection study called probability of detection (POD) study. In many instances, the NDE flaw detectability is given as a flaw size such as crack length. The flaw is either a crack or behaving like a crack in terms of affecting the structural integrity of the material. An alternate approach is to use a more complex flaw size parameter. The X-ray flaw size parameter, given here, takes into account many setup and geometric factors. The flaw size parameter relates to X-ray image contrast and is intended to have a monotonic correlation with the POD. Some factors such as set-up parameters, including X-ray energy, exposure, detector sensitivity, and material type that are not accounted for in the flaw size parameter may be accounted for in the technique calibration and controlled to meet certain quality requirements. The proposed flaw size parameter and the computer application described here give an alternate approach to conduct the POD studies. Results of the POD study can be applied to reliably detect small flaws through better assessment of effect of interaction between various geometric parameters on the flaw detectability. Moreover, a contrast simulation algorithm for a simple part-source-detector geometry using calibration data is also provided for the POD estimation.

Koshti, Ajay M.

2014-01-01

350

Modeling the X-Ray Process, and X-ray Flaw Size Parameter for POD Studies  

NASA Technical Reports Server (NTRS)

Nondestructive evaluation (NDE) method reliability can be determined by a statistical flaw detection study called probability of detection (POD) study. In many instances the NDE flaw detectability is given as a flaw size such as crack length. The flaw is either a crack or behaving like a crack in terms of affecting the structural integrity of the material. An alternate approach is to use a more complex flaw size parameter. The X-ray flaw size parameter, given here, takes into account many setup and geometric factors. The flaw size parameter relates to X-ray image contrast and is intended to have a monotonic correlation with the POD. Some factors such as set-up parameters including X-ray energy, exposure, detector sensitivity, and material type that are not accounted for in the flaw size parameter may be accounted for in the technique calibration and controlled to meet certain quality requirements. The proposed flaw size parameter and the computer application described here give an alternate approach to conduct the POD studies. Results of the POD study can be applied to reliably detect small flaws through better assessment of effect of interaction between various geometric parameters on the flaw detectability. Moreover, a contrast simulation algorithm for a simple part-source-detector geometry using calibration data is also provided for the POD estimation.

Khoshti, Ajay

2014-01-01

351

Valuation method for effects of hot stamping process parameters on product properties using hot forming simulator  

Microsoft Academic Search

Hot stamping is one of the hot forming processes for manufacturing products of lightweight construction such as lightweight vehicles. Knowledge on the characteristics of the hot stamping process is significant in designing and optimizing the process conditions, dies and tools; however, until now, the characteristics of this process, such as the relationships between a product property and die temperature and

Katsuyoshi Ikeuchi; Jun Yanagimoto

2011-01-01

352

Effect of process parameters on deep drawing of Ti-6Al-4V alloy using finite element analysis  

NASA Astrophysics Data System (ADS)

Deep drawing process depends on the large number of process parameters and their interdependence. Optimization of process parameters in deep drawing is a vital task to reduce manufacturing cost and understand their influence on the deformation behaviour of the sheet metal. In this paper, significance of important process parameters namely, punch speed, blank holder pressure (BHP) and temperature on the deep-drawing characteristics of a Ti-6Al-4V alloy are investigated. Taguchi technique was employed to identify the influence of these parameters on thickness distribution. The finite element model of deep drawing process has been built up and analyzed using Dynaform version 5.6.1 with LS-Dyna version 971 as solver. Based on the predicted thickness distribution of the deep drawn circular cup and analysis of variance (ANOVA) results, it is concluded that punch speed has the greatest influence on the deep drawing of Ti-6Al-4V alloy blank sheet. Temperature and BHP effect are negligible in deep drawing of Ti-6Al-4V alloy at low warm temperatures (less than 450°C) but it may contribute to a significant extent at higher temperature. Also thickness distribution is predicted using artificial neural network (ANN). It is observed that the predicted thickness distribution is in good agreement with the experimental data.

Kotkunde, Nitin; Deole, Aditya D.; Gupta, A. K.; Singh, S. K.

2013-12-01

353

Evaluation of Die Chilling Effects during Forging of Nimonic-80A Superalloy  

SciTech Connect

Nimonic-80A is a kind of nickel-based superalloys which is used in high temperature components of land gas turbines. In this paper, the influence of four design factors: die temperature, strain rate, friction coefficient and geometry size of ring sample over the variation of internal diameters (VID) and forging load (FL) was studied. It was done by means of design methodology based on DOE-designated full factorial and FE simulations. FEM and experimental results showed that the variation of internal diameters and forging load had inverse proportion to the die temperature. Regression models were developed by using the response surface methodology (RSM) for VID and FL. Rate of the dynamic recrystallization varied depending on different amounts of die temperature. The results can be used in the semi-isothermal forging of complex part of the Nimonic-80A.

Shahriari, D. [Mapna Group, Mavadkaran Eng. Co., R and D Dept., Tehran (Iran, Islamic Republic of); Manufacturing Group, Mechanical Engineering Department, Faculty of Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Mechanical Engineering Department, Manufacturing Group, Iran University of Science and Technology in Arak Technical and Engineering School, Arak (Iran, Islamic Republic of); Sadeghi, M. H.; Amiri, A. [Manufacturing Group, Mechanical Engineering Department, Faculty of Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Cheraghzadeh, M. [Mapna Group, Mavadkaran Eng. Co., R and D Dept., Tehran (Iran, Islamic Republic of)

2010-06-15

354

Gas and Heat Transport Parameters for Sands during Drying and Wetting Processes in the Capillary Water Zone  

NASA Astrophysics Data System (ADS)

Gas and heat transport parameters such as soil-gas diffusion coefficient (Dp), air permeability (ka), and thermal conductivity (kT) are governing parameters for gas and heat transport behaviors in soils. Degree of water-saturation at different water potentials highly affects these gas and heat transport parameters. In this study, the effects of drying and wetting processes in the capillary water zone (water matric potential ranging from 0 to - 100 cm H2O) on the Dp, ka, and kT were investigated using different sand size fractions with different particle shapes and compaction levels (i.e., bulk density). Based on the measured data, threshold air-filled porosities for Dp and ka, air-filled pore-tortuosiy, and effective pore diameter for gas transport under drying and wetting processes, and their relations with particles shape, particle size, and compaction levels were discussed.

Sasanuma, K.; Hamamoto, S.; Kawamoto, K.; Sakaki, T.; Komatsu, T.

2012-12-01

355

Model-based analysis of coupled equilibrium-kinetic processes: indirect kinetic studies of thermodynamic parameters using the dynamic data.  

PubMed

Thermodynamic studies of equilibrium chemical reactions linked with kinetic procedures are mostly impossible by traditional approaches. In this work, the new concept of generalized kinetic study of thermodynamic parameters is introduced for dynamic data. The examples of equilibria intertwined with kinetic chemical mechanisms include molecular charge transfer complex formation reactions, pH-dependent degradation of chemical compounds and tautomerization kinetics in micellar solutions. Model-based global analysis with the possibility of calculating and embedding the equilibrium and kinetic parameters into the fitting algorithm has allowed the complete analysis of the complex reaction mechanisms. After the fitting process, the optimal equilibrium and kinetic parameters together with an estimate of their standard deviations have been obtained. This work opens up a promising new avenue for obtaining equilibrium constants through the kinetic data analysis for the kinetic reactions that involve equilibrium processes. PMID:25723920

Emami, Fereshteh; Maeder, Marcel; Abdollahi, Hamid

2015-05-01

356

Process parameter selection for optimizing the weld pool geometry in the tungsten inert gas welding of stainless steel  

Microsoft Academic Search

In this paper, the selection of process parameters for obtaining an optimal weld pool geometry in the tungsten inert gas (TIG) welding of stainless steel is presented. Basically, the geometry of the weld pool has several quality characteristics, for example, the front height, front width, back height and back width of the weld pool. To consider these quality characteristics together

S. C Juang; Y. S Tarng

2002-01-01

357

Sensitivity analysis and parameter estimation in a model of anaerobic waste water treatment processes with substrate inhibition  

Microsoft Academic Search

Anaerobic waste water treatment processes are commonly presented by the fifth order Hill and Barth non-linear model, describing three main stages of anaerobic digestion. The model investigated in the present work is a modified version of the Hill and Barth model, which includes substrate inhibition of growth of methanogenic bacteria. Parameter estimation of this model is a difficult problem because

N. A. Noykova; M. Gyllenberg

2000-01-01

358

Laser transmission welding of ABS: Effect of CNTs concentration and process parameters on material integrity and weld formation  

NASA Astrophysics Data System (ADS)

This paper reports a study of the laser transmission welding of polymeric joints composed by two ABS (acrylonitrile/butadiene/styrene) sheets, one transparent (natural ABS) and the other absorbent (filled by different percentages of carbon nanotubes (CNTs)). The objective of this work is to analyze the effect of process parameters and CNTs concentrations on weld formation and mechanical resistance of the weld joints.

Rodríguez-Vidal, E.; Quintana, I.; Gadea, C.

2014-04-01

359

Lipase-catalysed acylglycerol synthesis of glycerol and n ? 3 PUFA from tuna oil: Optimisation of process parameters  

Microsoft Academic Search

Enzymatic synthesis of acylglycerols from glycerol and n?3 polyunsaturated fatty acids concentrates, prepared from tuna oil, was optimised by response surface methodology. Acylglycerol synthesis was performed using Lipozyme Novo 435 under different reaction conditions according to the experiment design. Five factors were chosen to optimise the process parameters of lipase-catalysed synthesis. The results indicated that the esterification degree was above

Shucheng Liu; Chaohua Zhang; Pengzhi Hong; Hongwu Ji

2007-01-01

360

31 CFR 355.11 - What should I do if the endorsement on my check is forged or unauthorized?  

Code of Federal Regulations, 2010 CFR

...What should I do if the endorsement on my check is forged or unauthorized? 355.11...DEBT REGULATIONS GOVERNING FISCAL AGENCY CHECKS § 355.11 What should I do if the endorsement on my check is forged or unauthorized? If we...

2010-07-01

361

Modeling and analysis of the effects of processing parameters on the performance characteristics in the high pressure die casting process of Al–SI alloys  

Microsoft Academic Search

The high pressure die casting (HPDC) process has achieved remarkable success in the manufacture of aluminum–silicon (Al–SI)\\u000a alloy components for the modern metal industry. Mathematical models are proposed for the modeling and analysis of the effects\\u000a of machining parameters on the performance characteristics in the HPDC process of Al–SI alloys which are developed using the\\u000a response surface methodology (RSM) to

Ko-Ta Chiang; Nun-Ming Liu; Te-Chang Tsai

2009-01-01

362

Optimization of injection molding process parameters using combination of artificial neural network and genetic algorithm method  

Microsoft Academic Search

Injection molding is the most widely used process in manufacturing plastic products. Since the quality of injection molded plastic parts are mostly influenced by process conditions, how to determine the optimum process conditions becomes the key to improving the part quality. In this paper, a combining artificial neural network and genetic algorithm (ANN\\/GA) method is proposed to optimize the injection

Changyu Shen; Lixia Wang; Qian Li

2007-01-01

363

The Development of a Ceramic Mold for Hot-Forging of Micro-Magnets  

SciTech Connect

A new mold material has been developed for use in making rare-earth permanent magnet components with precise dimensions in the 10 to 1000 µm range by hot-forging. These molds are made from molds poly(methyl)methacrylate (PMMA) made by deep x-ray lithography (DXRL). An alumina bonded with colloidal silica has been developed for use in these molds. This material can be heated to 950°C without changing dimensions where it develops the strength needed to withstand the hot-fmging conditions (750°C, 100 MPa). In addition, it disintegrates in HF so that parts can be easily removed after forging.

Christenson, Todd; Garino, Terry

1999-06-25

364

Phased Array Inspection of Titanium Disk Forgings Targeting no. 1/2 FBH Sensitivity  

SciTech Connect

The phased array implementation of a focused zoned ultrasonic inspection to achieve a >3dB signal-to-noise for no. 1/2 flat bottom holes (FBH) in titanium is reported. Previous work established the ultrasound focusing required to achieve the targeted sensitivity. This work reports on the design of a phased array transducer capable of maintaining the needed focus to the depths required in the forging inspection. The performance of the phased array inspection is verified by examining signal-to-noise of no. 1/2 FBHs contained in coupons cut from actual forgings.

Roberts, R.A.; Friedl, J. [Center for NDE, Iowa State University, Ames, IA 50011 (United States)

2005-04-09

365

The tribological behaviour of detonation sprayed coatings: the importance of coating process parameters  

Microsoft Academic Search

The tribological performance of thermal spray coatings depends on a host of properties like coating composition, nature of phases and their distribution, microstructure, porosity and residual stress. All these properties, in turn, determine the hardness of the coating, which is conventionally used as the primary correlating parameter for evaluating wear resistance. To assess such an interrelationship in the case of

G. Sundararajan; D. Sen; G. Sivakumar

2005-01-01

366

Procedure for identifying pulse wave parameters in computer processing of photoplethysmographic signal  

Microsoft Academic Search

Measurement and monitoring of the physical parameters of human blood circulation occupies an important position in the complex problem of automating clinical investigation and diagnosis of cardiovascular diseases. The wide occurrence of these diseases and the increasing interest of physicians and physiologists in hemodynamic study of various aspects of human activity necessitate development of high-efficiency methods and systems for real-time

T. R. Shikhmamedov; B. I. Podlepetskii

1993-01-01

367

Parameter estimation and model comparison for stochastic epidemiological processes in a Bayesian framework  

NASA Astrophysics Data System (ADS)

We compare two stochastic epidemiological models in a Bayesian framework, both models performing on the same simulated data set. In some cases of data obtained under one model with specific parameter values the model comparison favours the model not underlying the simulated data.

Mateus, Luis; Stollenwerk, Nico; Zambrini, Jean Claude

2012-09-01

368

Processes and parameters involved in modeling radionuclide transport from bedded salt repositories. Final report. Technical memorandum  

Microsoft Academic Search

The parameters necessary to model radionuclide transport in salt beds are identified and described. A proposed plan for disposal of the radioactive wastes generated by nuclear power plants is to store waste canisters in repository sites contained in stable salt formations approximately 600 meters below the ground surface. Among the principal radioactive wastes contained in these canisters will be radioactive

D. E. Evenson; T. A. Prickett; P. A. Showalter

1979-01-01

369

The effect of hydrodynamic dispersion parameters on process optimization of S-109 partial waste retrieval  

SciTech Connect

The removal of cesium by draining the supernate and interstitial salt solution from the salt-cake while fresh water is continuously being added at the top of the tank requires modeling of the transport in variably saturated porous media, and possibly includes a diffusion component. The uncertainties in this method are based on the highly inhomogeneous properties of the salt-cake and limited knowledge of the drainage and transport parameters, more specifically, its hydraulic constraints and hydrodynamic dispersion properties. The hydraulic parameters of the salt-cake (hydraulic conductivity and van Genuchten parameters) have significance with respect to tank drainage and re-saturation and determine the kinetics of the flow through the salt waste. The unsaturated properties are needed in order to assess not only the time frame of tank drainage but also the equilibrium conditions. One of the most important parameters for determining the transport properties of the porous media is the hydrodynamic dispersion tensor. The hydrodynamic dispersion can be applied to describe the spreading of cesium mass spatially and temporally. It combines effects from local variations in pore fluid velocity dispersion and molecular diffusion. In this study, the hydrodynamic dispersion parameters, the Peclet number for molecular diffusion, and the resulting uncertainties have been estimated from pilot scale column experiments using S-109 salt-cake simulant. A 2-D axisymmetric finite element model has been developed to couple the flow in variably saturated regime with transport of non-reacting cesium. The model used unsaturated hydraulic properties as determined from previous experimental work. The study performed sensitivity analysis of the hydrodynamic dispersion factor and provided information about its significance with respect to cesium temporal and spatial distribution. The model was used to compare relevant operating parameters during the replacement of cesium rich supernatant with fresh water. The effects of hydrodynamic dispersion variations were analyzed to predict the uncertainty of the volumes that must be added and pumped for the concentration of cesium to drop below the limits required by the Demonstration Bulk Vitrification System (DBVS) facility. These parameters were used to determine the most optimal drainage scenarios, which are driven by minimization of the Double Shell Tank (DST) space needed. (authors)

Tachiev, F.; Yaari, G.; Foster, N. [Florida International Univ., Miami (United States); Blaine, B. [CH2MHILL (United States)

2007-07-01

370

LIDAR Data Acquisition and Processing for assessing critical fuel parameters: the case study of Bosco dell  

NASA Astrophysics Data System (ADS)

In the last decades, the abandonment of rural areas has caused an increasing accumulation of fuels (the organic matter available for ignition and combustion) which is considered very critical for the whole Mediterranean Basin because fire ignition and propagation depend strongly on the availability and structure of wild land fuels. Detailed information on fuel properties (e.g. fuel load, spatial arrangement, structure, status etc.) and fuel distribution are essential for supporting (i) fuel management, (ii) fire behaviour prediction (iii) real-time fire suppression tactics and (iv) logistics decisions. Airborne full-waveform laser scanning (ALS) is a potential tool for accurately and effectively assessing critical fuel parameters (including canopy bulk density, canopy height, canopy fuel weight, and canopy base height) over forest areas. The LIDAR is an active high resolution technology capable to provide accurate three dimensional forest structure measurements. The aim of this paper is to develop the use of lidar (LIght Detection and Ranging) remote sensing for accurately and effectively assessing fuel critical parameters in a natural protected area (Bosco dell'Incoronata) located in the Apulia Region (Southern Italy). Lidar data acquisition was carried out on April 2008 for both Bosco dell'Incoronata and surrounding areas. An integrated approach was used to identify and characterize critical fuel parameters using a combination of lidar height bins and ortophotos. Estimates of fuel properties were compared with in-situ data collected at the same time (more or less) as the LIDAR data acquisition. Specific goals of our analysis include: (1) developing lidar derived products and the methodology to use them for assessing critical fuel parameters, and (2) producing spatially explicit digital fuel maps. The obtained results pointed out that LIDAR-based fuel properties and prediction models can be fruitfully used for mapping critical fuel parameters (including canopy bulk density, canopy height, canopy fuel weight, and canopy base height) over extensive forest areas.

Guariglia, A.; Zampino, A.; Lasaponara, R.; Lanorte, A.

2009-04-01

371

Effect of HVOF Processing Parameters on the Properties of NiCoCrAlY Coatings by Design of Experiments  

NASA Astrophysics Data System (ADS)

The effect of three principal, independent, high-velocity oxygen fuel (HVOF)-processing parameters on the properties of NiCoCrAlY coatings deposited using commercial powders is reported here. The design of experiments (DoE) technique at a two-level factorial and a central composite rotatable design was used to analyze and optimize the HVOF spraying process. The deposition parameters investigated were (1) fuel flow, (2) oxygen flow, and (3) stand-off distance. The effect of these processing variables was evaluated using selected responses, including porosity and oxide content, residual stresses, and deposition efficiency. Coatings with low porosity as well as with low residual stress were obtained using high fuel-rich conditions at a stand-off distance between 250 and 300 mm. At shorter and longer stand-off distances, respectively, either excessive flattening of splats or un-molten condition occurred, resulting in high levels of porosity and residual stress. The response surface, the empirical relationships among the variables, and the response parameters allowed the selection of optimum deposition parameters and the improvement of coating properties.

Ruiz-Luna, H.; Lozano-Mandujano, D.; Alvarado-Orozco, J. M.; Valarezo, A.; Poblano-Salas, C. A.; Trápaga-Martínez, L. G.; Espinoza-Beltrán, F. J.; Muñoz-Saldaña, J.

2014-08-01

372

Effect of processing parameter and filler content on tensile properties of multi-walled carbon nanotubes reinforced polylactic acid nanocomposite  

NASA Astrophysics Data System (ADS)

Polymer nanocomposite of multi-walled carbon nanotubes (MWCNT) nanoparticles incorporated with polylactic acid (PLA) and liquid natural rubber (LNR) as compatibilizer were prepared via melt blending method using the Haake Rheomix internal mixer. In order to obtain the optimal processing parameter, the nanocomposite with 89 wt % of PLA was blended with 10 wt % of LNR and 1 wt % of MWCNTs were mixed with various mixing parameter condition; mixing temperature, mixing speed and mixing time. The optimum processing parameter of the composites was obtained at temperature of 190°C, rotation speed of 90 rpm and mixing time of 14 min. Next, the effect of MWCNTs loading on the tensile properties of nanocomposites was investigated. The nanocomposites were melt blended using the optimal processing parameter with MWCNTs loading of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4 wt %. The result showed that the sample with 3.5 wt % of MWCNTs gave higher tensile strength and Young's modulus. The SEM micrographs confirmed the effect of good dispersion of MWCNTs and their interfacial bonding in PLA nanocomposites. However, the elongation at break decreased with increasing the percentage of MWCNTs.

Ali, Adilah Mat; Ahmad, Sahrim Hj.

2013-05-01

373

Influence of some formulation and process parameters on the stability of lysozyme incorporated in corn flour- or corn starch-based extruded materials prepared by melt blending processing.  

PubMed

In order to obtain an antimicrobial biodegradable material, corn flour was extruded with 1% of lysozyme. Since the limited stability of natural preservatives such as lysozyme is a common bottleneck to the elaboration of active biomaterials by melt blending processes, the influence of formulation and of extrusion processing temperature on its residual enzymatic activity was investigated. To assess the contribution of process parameters such as temperature, shear stress and of related formulation parameters such as glycerol and moisture contents, the stability of lysozyme following its extrusion or its thermoforming with plasticized corn starch or thermal treatments in aqueous glycerol solutions was also studied. Increasing glycerol content from 25% to 30% significantly limited inactivation of lysozyme during extrusion, while increasing initial moisture content of the mixture from 14.5% to 28.5% had the opposite effect. These observations open the possibility to prepare active materials retaining more than 60±7% of initial lysozyme activity. PMID:25442947

Jbilou, Fouzia; Galland, Sophie; Telliez, Camille; Akkari, Zied; Roux, Roselyne; Oulahal, Nadia; Dole, Patrice; Joly, Catherine; Degraeve, Pascal

2014-12-01

374

Influence of Laser Processing Parameters on Microstructure and Corrosion Kinetics of Laser-Treated ZE41 Magnesium Alloy  

NASA Astrophysics Data System (ADS)

In the present study, surface melting of a magnesium alloy, ZE41, was performed with an Nd:YAG laser using different laser parameters. The microstructure of the laser-treated and untreated specimens was analyzed by optical and scanning electron microscopy and X-ray diffraction. Corrosion resistance of the different laser-treated specimens along with the untreated alloy was characterized using electrochemical impedance spectroscopy and weight loss measurements in 0.001 M sodium chloride solution. Although the laser processing parameters influenced the microstructure and the melt depth of the laser-treated zone, these had little effect on the corrosion resistance of the alloy.

Chakraborty Banerjee, P.; Singh Raman, R. K.; Durandet, Y.; McAdam, G.

2013-05-01

375

The Energy Quanta and the Entropy — New Parameters for Identification of the Machining Processes  

Microsoft Academic Search

The contribution presents some new findings in search for a more comprehensive description of the machining processes, such as turning, milling and drilling. The experimentally determined power spectra of the input, transformation and output energy are used for computing the energy quanta and the entropy of the processes. It is shown, that the change of the entropy allows to explain

J. Peklenik; S. Dolinšek

1995-01-01

376

Standardization of process parameters for a chemical reaction using neutron activation analysis technique  

Microsoft Academic Search

The chemical process to convert polyepichlorohydrin (PECH) into a glycidyl azide polymer (GAP) has been standardized by measuring the relative concentrations of nitrogen, chlorine and oxygen with the fast neutron activation analysis technique. For comparison PECH and GAP samples were also analysed by IR spectroscopy. The results indicate that, for standardization of the present chemical process, the fast neutron activation

P. A. Dokhale; V. N. Bhoraskar

1996-01-01

377

Femtosecond laser ablation properties of transparent materials: impact of the laser process parameters on the machining throughput  

NASA Astrophysics Data System (ADS)

High average power, high repetition rate femtosecond lasers with ?J pulse energies are increasingly used for bio-medical and material processing applications. With the introduction of femtosecond laser systems such as the SpiritTM platform developed by High Q Lasers and Spectra-Physics, micro-processing of solid targets with femtosecond laser pulses have obtained new perspectives for industrial applications [1]. The unique advantage of material processing with subpicosecond lasers is efficient, fast and localized energy deposition, which leads to high ablation efficiency and accuracy in nearly all kinds of solid materials. The study on the impact of the laser processing parameters on the removal rate for transparent substrate using femtosecond laser pulses will be presented. In particular, examples of micro-processing of poly-L-lactic acid (PLLA) - bio-degradable polyester and XensationTM glass (Schott) machined with SpiritTM ultrafast laser will be shown.

Matylitsky, V. V.; Hendricks, F.; Aus der Au, J.

2013-03-01

378

Numerical simulation of ring rolling process - Application to superalloy 718 parts  

Microsoft Academic Search

Numerical simulation has become a powerful tool that enables to save costs and time in the design and manufacturing of forged parts for aircraft engines. A complete simulation ``package'' based on the software code Forge® is used at Snecma to predict the properties of such parts and optimize the manufacturing processes. In order to have a good prediction of the

D. Chabin; P. Y. Emptas; M. Bouzaiane

2007-01-01

379

Improved CD uniformity as a function of developer chemistry and process parameters derived from a statistically designed experiment  

NASA Astrophysics Data System (ADS)

A series of experiments was run to determine the chemical and process effects on CD uniformity for Dynachem's new dyed photoresist, NOVA 2050 AR, when developed with metal ion free and metal ion type developers. The matrix of experiments included variations in spray time and puddle time, but with the constraint that all experiments had the same total time for spray and puddle times. In order to do this type of matrix it was necessary to make an unusual use of a mixture model to devise the experimental design. The design was devised to look at the effects of one-puddle, twopuddle, three-puddle and all-spray processes. Also, the effect of using either metal ion free or metal type developers was examined by running the matrix with Dynalith EPD-85 and DE-3 (0.5%) as respective examples of the two developer types. Before beginning the above matrix the baseline parameters for nozzle position, puddle time, spray time, spray speed, pre-wet time, spray pressure and spray time were determined via a Plackett- Burinan design of experiments. These three studies when compiled and analyzed with the statistical software package, RS-l, served to separate the effects of process parameters and developer type according to their effect on CD uniformity. These results suggest that three-puddle metal ion free develop processes were superior. Graphs will be shown that illustrate which parameters are the most influential concerning CD uniformity. A mathematical model will be presented that will allow the calculation of the standard deviation for CD uniformity with 95% confidence for any given set of spray and puddle times. These data and models will thereby give guidance to the process engineer how to best use developer type and process in order to obtain the best CD uniformity for a 1.0 micron process.

Christensen, Lorna D.; Bell, Ken L.; Acuna, Nadine A.

1990-06-01

380

Effect of process parameters on properties of argon–nitrogen plasma for titanium nitride film deposition  

SciTech Connect

In this study, the effect of working pressure and input power on the physical properties and sputtering efficiencies of argon–nitrogen (Ar/N{sub 2}) plasma in direct current magnetron discharge is investigated. The discharge in Ar/N{sub 2} is used to deposit TiN films on high speed steel substrate. The physical plasma parameters are determined by using Langmuir probe and optical emission spectroscopy. On the basis of the different reactions in the gas phase, the variation of plasma parameters and sputtering rate are explained. A prominent change of electron temperature, electron density, ion density, and degree of ionization of Ar is found as a function of working pressure and input power. The results also show that increasing working pressure exerts a negative effect on film deposition rate while increasing input power has a positive impact on the same. To confirm the observed physical properties and evaluate the texture growth as a function of deposition parameters, x-ray diffraction study of deposited TiN films is also done.

Saikia, Partha; Kakati, Bharat [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782 402, Kamrup, Assam (India)] [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782 402, Kamrup, Assam (India)

2013-11-15

381

Influence of laser parameters on quality of microholes and process efficiency  

NASA Astrophysics Data System (ADS)

To enable the direct-spinning process of super-micro fibres (< 0.5 dtex) suitable for novel medical, hygienical and technical products microhole arrays with diameters down to 25 ?m in very high quality are required. Using ultrashort pulses together with a helical drilling optics microholes with high accuracy were manufactured in metals of a thickness in the range of 0.3 mm. However, the required process time for a single microhole ranges up to several ten seconds. Simple energy balance considerations show that higher averaged powers - either achieved with larger pulse energies or an increased repetition rate - considerable reduce the process time. In this case plasma formation and heat accumulation show an increased formation of melt and recast. Thus, the objective is to increase the productivity while maintaining consistent quality of the microholes. With this aim, the influence of pulse energy and repetition rate on the borehole geometry, processing quality and process efficiency was investigated for helical drilling. In the present research work a TruMicro 5250 laser source (tp = 8 ps, ?=515 nm, fR=800 kHz) was used. To determine the process time of the microhole the transmitted laser radiation was recorded. A systematic evaluation of the process quality and process time dependent on pulse energy and repetition rate will be presented in this contribution. First laser manufactured spinning nozzles with microhole diameters down to 25 ?m processed in 0.24 mm thick AuPt alloy were used to fabricate unique super-micro fibres with yarn counts down to 0.2 dtex.

Feuer, A.; Kunz, C.; Kraus, M.; Onuseit, V.; Weber, R.; Graf, T.; Ingildeev, D.; Hermanutz, F.

2014-03-01

382

Standardization of process parameters for a chemical reaction using neutron activation analysis technique  

NASA Astrophysics Data System (ADS)

The chemical process to convert polyepichlorohydrin (PECH) into a glycidyl azide polymer (GAP) has been standardized by measuring the relative concentrations of nitrogen, chlorine and oxygen with the fast neutron activation analysis technique. For comparison PECH and GAP samples were also analysed by IR spectroscopy. The results indicate that, for standardization of the present chemical process, the fast neutron activation analysis technique is superior to IR spectroscopy. In this paper the techniques used to analyse the samples are described in detail but the information on the actual chemical process adopted is provided in brief.

Dokhale, P. A.; Bhoraskar, V. N.

1996-08-01

383

Characterization of Cracking and Crack Growth Properties of the C5A Aircraft Tie-Box Forging  

NASA Technical Reports Server (NTRS)

Detailed destructive examinations were conducted to characterize the integrity and material properties of two aluminum alloy (7075-T6) horizontal stabilizer tie box forgings removed.from US. Air Force C5A and C5B transport aircraft. The C5B tie box forging was,found to contain no evidence of cracking. Thirteen cracks were found in the CSA,forging. All but one of the cracks observed in the C5A component were located along the top cap region (one crack was located in the bottom cap region). The cracks in the C5A component initiated at fastener holes and propagated along a highly tunneled intergranular crack path. The tunneled crack growth configuration is a likelv result of surface compressive stress produced during peening of the .forging suijace. The tie box forging ,fatigue crack growth, fracture and stress corrosion cracking (SCC) properties were characterized. Reported herein are the results of laboratory air ,fatigue crack growth tests and 95% relative humidity SCC tests conducted using specimens machined from the C5A ,forging. SCC test results revealed that the C5A ,forging material was susceptible to intergranular environmental assisted cracking: the C5A forging material exhibited a SCC crack-tip stress-intensity factor threshold of less than 6 MPadn. Fracture toughness tests revealed that the C5A forging material exhibited a fracture toughness that was 25% less than the C5B forging. The C5A forging exhibited rapid laboratory air fatigue crack growth rates having a threshold crack-tip stress-intensity factor range of less than 0.8 MPa sup m. Detailed fractographic examinations revealed that the ,fatigue crack intergranular growth crack path was similar to the cracking observed in the C5A tie box forging. Because both fatigue crack propagation and SCC exhibit similar intergranular crack path behavior, the damage mechanism resulting in multi-site cracking of tie box forgings cannot be determined unless local cyclic stresses can be quantified.

Piascik, Robert S.; Smith, Stephen W.; Newman, John A.; Willard, Scott A.

2003-01-01

384

Ultrasonic Processing of Materials  

Microsoft Academic Search

The purpose of this project was to determine the impact of a new breakthrough technology, ultrasonic processing, on various industries, including steel, aluminum, metal casting, and forging. The specific goals of the project were to evaluate core principles and establish quantitative bases for the ultrasonc processing of materials, and to demonstrate key applications in the areas of grain refinement of

Thomas T. Meek; Qingyou Han; Xiaogang Jian; Hanbing Xu

2005-01-01

385

T & I--Metalworking, Forging. Kit No. 55. Instructor's Manual [and] Student Learning Activity Guide.  

ERIC Educational Resources Information Center

An instructor's manual and student activity guide on forging are provided in this set of prevocational education materials which focuses on the vocational area of trade and industry (metalworking). (This set of materials is one of ninety-two prevocational education sets arranged around a cluster of seven vocational offerings: agriculture, home…

Lake, Robert J.

386

HotEye (tm) Based Coordinate Measuring Machine for Forging Industry  

SciTech Connect

The objective of this project is to develop a 3 dimensional measurement system for the domestic forging industry based on HotEye{trademark}. This technology will allow high definition camera to accurately image a red hot object. The project marries conventional Coordinate Measurement Machine ''CMM'' technology to HotEye{trademark} technology to permit the accurate measurement of forged parts while they are at high temperature. Being able to take such measurements will dramatically reduce the amount of scrap produced by the domestic forging industry. This industry wastes a significant amount of energy because of the high rate of scrap it produces. OGT will: (1) Develop a 3D measurement sensor head that will work on a part at a temperature up to 1,450 C with an accuracy of 0.1mm or better and with a scanning speed of less than 10 seconds for an area of 100mm x 100mm. (2) Develop a Virtual-Fixturing software package to alleviate the need of precise hard fixturing. (3) Integrate the 3D measurement sensor head and the Virtual-Fixturing software into a standard CMM, both hardware (replacing the probes) and software (data format and user interface match) so that the system can automatically perform a complete preprogrammed measurement of a hot product. (4) Test and evaluate the system in a forging facility.

OG Technologies

2003-06-09

387

iPads as Placed Resources: Forging Community in Online and Off line Spaces  

ERIC Educational Resources Information Center

The article focuses on the notion of tablet technologies as placed resources (Prinsloo, 2005; Prinsloo & Rowsell, 2012) by exploring how an international research project in Australia, Canada, and the United States forged community through online spaces. There is a tendency in media and in literature to romanticize technologies like iPads as a…

Rowsell, Jennifer; Saudelli, Mary Gene; Scott, Ruth Mcquirter; Bishop, Andrea

2013-01-01

388

Social Work and Engineering Collaboration: Forging Innovative Global Community Development Education  

ERIC Educational Resources Information Center

Interdisciplinary programs in schools of social work are growing in scope and number. This article reports on collaboration between a school of social work and a school of engineering, which is forging a new area of interdisciplinary education. The program engages social work students working alongside engineering students in a team approach to…

Gilbert, Dorie J.

2014-01-01

389

Modelling the role of non metallic inclusions on the anisotropic fatigue behaviour of forged steel  

E-print Network

. This study aims at describing the high cycle fatigue response of a forged bainitic steel. This material manganese-sulfide inclusion clusters are the origin of crack initiation and the fatigue strength drops Cycle Fatigue. Keywords: High cycle fatigue; Anisotropy; Manganese Sulphide Inclusions; Probability

Paris-Sud XI, Université de

390

Multiaxial fatigue criterion accounting for anisotropy in forged components , Y. Chastel1  

E-print Network

Multiaxial fatigue criterion accounting for anisotropy in forged components M. Milesi1 , Y. Chastel-olivier.bouchard@ensmp.fr ABSTRACT: Numerical modelling of fatigue behavior for anisotropic structures has become critical for de elementary volume. It can then be used to improve and refine the Papadopoulos fatigue criterion by taking

Boyer, Edmond

391

Gradient, Non-Gradient and Hybrid Algorithms for Optimizing 3D Forging Sequences with Uncertainties  

E-print Network

in order to minimize the potential of fold formation. Keywords: Optimization Algorithm, Response Surface be substituted to the exact evaluations of the objective function within costly global algorithmsGradient, Non-Gradient and Hybrid Algorithms for Optimizing 3D Forging Sequences with Uncertainties

Paris-Sud XI, Université de

392

[Methodological study on calibrating and validating model parameters of MUCT processes at low C/N ratio].  

PubMed

Basing on ASM2d, established a mathematical model to describe the transformation of COD, TN, NH4(+)-N and TP. In terms of comparison between simulation and observed values, the kinetics and stoichiometric parameters were established in MUCT process treating a wastewater with low C/N ratio. The results showed that, the q(PHA), K(A), K(pp), Y(PO4(3-), micro(AUT) and eta(NO3(-) were 2.90 g x (g x d)(-1), 3.85 g x m(-3), 1.35 g x (g x d)(-1), 0.35, 1.6 and 0.8, respectively. The typical parameters given by the ASM2d were used as others kinetic and stoichiometric parameters. PMID:22295643

Wang, Xiao-Ling; Yin, Jun; Li, Shu-Kuan; Wei, Xin-Dong; Gao, Shang

2011-11-01

393

Processing Raw Data with Sequencher 1. Trim sequences using the "barcode parameters"  

E-print Network

sequencher project with the primers used to sequence. Contig these with the bigProcessing Raw Data with Sequencher 1. Trim sequences using the "barcode everything else into one big one ­ usually I use 60% similarity here, and 30

Mathis, Wayne N.

394

Key considerations for optimization of formulation and melt-extrusion process parameters for developing thermosensitive compound.  

PubMed

The melt-extrusion process is currently applied in the pharmaceutical field in the manufacturing of a variety of dosage forms and formulations, including solid dispersions. Though this technology is considered efficient and continuous, there are potential challenges of which, additional thermal degradation of drug substance because heat stress and shear forces are of a primary concern. This paper attempts to understand the impact of thermal and/or mechanical components of the melt-extrusion process on the stability of a thermosensitive drug substance during scale-up. The overall degradation profile of the drug substance was correlated with the various physical changes made to the extruder as well as the process temperature. The results suggested that the degradation profile of a thermosensitive drug substance could be controlled by proper design of screw assemblies and by optimization of screw rotations per minute, process temperature, and feed rate during development and scale-up. PMID:21284576

Ghosh, Indrajit; Vippagunta, Radha; Li, Shoufeng; Vippagunta, Sudha

2012-01-01

395

Effect of process parameters on bond formation during ultrasonic consolidation of aluminum alloy 3003  

Microsoft Academic Search

Ultrasonic consolidation (UC) is a novel additive manufacturing process wherein three-dimensional metallic objects are fabricated layer by layer in an automated fashion from thin metal foils. The process has immense potential for fabrication of injection molding tooling with conformai cooling channels, fiber-reinforced composites, multi-material structures, smart structures, and others. The proportion of bonded area in relation to the total interface

G. D. Janaki Ram; Y. Yang; B. E. Stucker

2006-01-01

396

Changes in Interface Parameters and Tensile Properties in Copper as a Consequence of Iterative Processing  

NASA Astrophysics Data System (ADS)

Both one-step and subsequent multistep grain boundary engineering processing of copper have been investigated. Specimens were tensile tested to failure after each stage of processing, and the microhardness was measured. These properties were linked to measurements of both the grain boundary misorientation and grain boundary plane distribution in order to provide insight into the mechanisms of microstructure evolution. Analysis of the stress-strain behavior revealed the balance between deformation and microstructure restoration occurring during processing. An increase in work hardening and a reduction in ductility were observed with successive processing iterations, indicating an accumulation of retained strain. This brought about stagnation in the microstructure, whereby no new ?3s were generated and grain boundary migration was stabilized. It was shown that ?3 boundaries are effective agents for dislocation pileup, and this strain-retention ability plays an important role in the early stages of iterative processing. Analysis of the data in terms of “incorporated” and “nonincorporated” ?3s indicated that iterative treatments are mechanistically different from one-step treatments. It was also shown that the ?9 and ?27 boundaries added to the microstructure as a consequence of iterative processing were not “special,” because they were on irrational boundary planes.

Coleman, Mark; Randle, Valerie

2008-09-01

397

Evaluation of the Deformation Behavior of a Semi-solid Hypereutectic Al-Si Alloy Compressed in a Drop-Forge Viscometer  

NASA Astrophysics Data System (ADS)

The rheological behavior of an Al-25 mass pct Si alloy, i.e., a hypereutectic Al-Si alloy, was investigated to determine its processability under semi-solid forming conditions. To measure the viscosity of the semi-solid alloy, a parallel-plate drop-forge viscometer similar to that devised by Yurko and Flemings was developed. Drop-forge experiments revealed that the viscosity initially decreased as the shear rate increased and subsequently increased as the shear rate decreased. Thus, the viscosity reached a minimum at approximately the maximum shear rate. The summarized relationship between the viscosity, ? [Pa s], and the shear rate, dot{? } [s-1], can be described by the power-law model ? = 1.78 × 107 dot{? } -1.5. The decrease in viscosity as a function of the shear rate derived from this equation depends on both the temperature and the applied force but not the duration of deformation. A convex curve was obtained when the effective duration of deformation, i.e., the actual compression time, was plotted as a function of the viscosity and the effective duration of deformation reached a maximum at approximately ? = 30 kPa s ( dot{? } = 70 s-1). The origin of this profile can be attributed to a combination of both a moderate working time and an adequate deformation, which resulted from a decrease in the deformation resistance accompanied by a lowering of the viscosity. The viscosity at the maximum effective duration of deformation thus corresponds to the transition point for the change in the flow process dominant factor from plastic forming (forging) to casting. Therefore, the viscosity ? = 30 kPa s is believed to be the optimum viscosity for the semi-solid forming of the Al-25 mass pct Si alloy. The approximate temperature condition can be ranged from 855 K to 859 K (582 °C to 586 °C).

Fukui, Yasuyoshi; Nara, Daisaku; Kumazawa, Noriyoshi

2015-02-01

398

Optimal one-parameter observables for the Abelian Z? in e+e-??+?- process  

NASA Astrophysics Data System (ADS)

To detect off-shell Abelian Z? boson in e+e-??+?-, we propose one-parameter observables with the best value-to-uncertainty ratio. The observables are constructed by angular integration of the differential cross-section with smooth weight functions. The value-to-uncertainty ratio is used as a criterion to select the unique weight function leading to the observable with the best statistical power for data analysis. The observables allow to select either vector or axial-vector Z? couplings to leptons. The obtained observable can be useful in future experiments at lepton colliders such as the ILC.

Gulov, Alexey

2014-10-01

399

Effect of fabrication parameters on the pore concentration of the aluminum metal foam, manufactured by powder metallurgy process  

Microsoft Academic Search

In this paper, the effect of fabrication parameters on the pore concentration of aluminum metal foam manufactured by powder\\u000a metallurgy process is studied. Aluminum metal foam specimens were fabricated from the mixture of aluminum powders (mean particle\\u000a size 60 ?m) and NaCl at 10,20,30,40(wt) % content under 200, 250, 300, MPa Pressures. All specimens were then sintered at\\u000a 630°C for 2.5

Sermin Ozan; Seda Bilhan

2008-01-01

400

Study of Antioxidant Capacity and Quality Parameters in An Orange Juice–Milk Beverage After High-Pressure Processing Treatment  

Microsoft Academic Search

The aim of this study was to obtain a beverage with a high content of bioactive compounds. Therefore, a mixture of orange\\u000a juice and milk was prepared. The effect of high-pressure processing (HPP), four different pressures (100, 200, 300, and 400 MPa),\\u000a four treatment times for each pressure (120, 300, 420, and 540 s) on antioxidant compounds, and quality parameters was studied.

Francisco J. Barba; Clara Cortés; María J. Esteve; Ana Frígola

401

Effects of process parameters on the soldering behavior of the eutectic Sn-Zn solder on Cu substrate  

Microsoft Academic Search

The effects of process parameters such as flux, dipping temperature and the heat-treatment on the soldering behaviors of the eutectic solder (composition: 91Sn-9Zn) hot-dipped on Cu substrates were investigated. The most suitable flux as tested was oleic acid for the eutectic Sn-Zn solder system hot-dipped on Cu substrate for the solder coverage. The adhesion strength obtained increased from 9.6±0.6 MPa

Shan-Pu Yu; Hsiu-Ju Lin; Min-Hsiung Hon; Moo-Chin Wang

2000-01-01

402

Influences of process parameters on tensile strength of friction stir welded cast A319 aluminium alloy joints  

Microsoft Academic Search

Fusion welding of cast A319 (Al-Si-Cu) alloy will lead to many problems including porosity, micro-fissuring, and hot cracking.\\u000a Friction Stir Welding (FSW) can be used to weld A319 alloy without these defects. In this investigation, an attempt has been\\u000a made to study the effect of FSW process parameters on the tensile strength of A319 alloy welded joints. Joints were made

M. Jayaraman; R. Sivasubramanian; V. Balasubramanian; S. Babu

2009-01-01

403

Taguchi's off line method and Multivariate loss function approach for quality management and optimization of process parameters -A review  

NASA Astrophysics Data System (ADS)

Off-line quality control is considered to be an effective approach to improve product quality at a relatively low cost. The Taguchi method is one of the conventional approaches for this purpose. Through this approach, engineers can determine a feasible combination of design parameters such that the variability of a product's response can be reduced and the mean is close to the desired target. The traditional Taguchi method was focused on ensuring good performance at the parameter design stage with one quality characteristic, but most products and processes have multiple quality characteristics. The optimal parameter design minimizes the total quality loss for multiple quality characteristics. Several studies have presented approaches addressing multiple quality characteristics. Most of these papers were concerned with maximizing the parameter combination of signal to noise (SN) ratios. The results reveal the advantages of this approach are that the optimal parameter design is the same as the traditional Taguchi method for the single quality characteristic; the optimal design maximizes the amount of reduction of total quality loss for multiple quality characteristics. This paper presents a literature review on solving multi-response problems in the Taguchi method and its successful implementation in various industries.

Bharti, P. K.; Khan, M. I.; Singh, Harbinder

2010-10-01

404

Developing LBM Process Parameters for Ti-6Al-4V Thin Wall Structures and Determining the Corresponding Mechanical Characteristics  

NASA Astrophysics Data System (ADS)

The Laser Beam Melting (LBM) process technology within the family of Additive Manufacturing technology is characterized by its ability to fabricate fully dense 3D structures directly from micro-sized metal powder. With the current state of the art, Ti-6Al-4V has been processed using LBM machine systems constituting a laser with a beam diameter of about 100 ?m. In order to fabricate structures with smaller wall thicknesses, processing of Ti-6Al-4V is attempted on the LBM machine system, Realizer SLM 50 consisting of a laser with a beam diameter 10 ?m. The proposed paper presents the development of process parameters for fabricating fully dense Ti-6Al-4V 3D structures using the LBM machine system, Realizer SLM 50. Further experiments are carried out to determine the wall thickness and mechanical properties achievable using the selected process parameters. Analysis and scientific arguments are presented to explain the influence of building direction and heat treatment on mechanical properties.

Ahuja, Bhrigu; Schaub, Adam; Karg, Michael; Lechner, Michael; Merklein, Marion; Schmidt, Michael

405

Determination of thermodynamic and transport parameters of naphthenic acids and organic process chemicals in oil sand tailings pond water.  

PubMed

Oil sand tailings pond water contains naphthenic acids and process chemicals (e.g., alkyl sulphates, quaternary ammonium compounds, and alkylphenol ethoxylates). These chemicals are toxic and can seep through the foundation of the tailings pond to the subsurface, potentially affecting the quality of groundwater. As a result, it is important to measure the thermodynamic and transport parameters of these chemicals in order to study the transport behavior of contaminants through the foundation as well as underground. In this study, batch adsorption studies and column experiments were performed. It was found that the transport parameters of these chemicals are related to their molecular structures and other properties. The computer program (CXTFIT) was used to further evaluate the transport process in the column experiments. The results from this study show that the transport of naphthenic acids in a glass column is an equilibrium process while the transport of process chemicals seems to be a non-equilibrium process. At the end of this paper we present a real-world case study in which the transport of the contaminants through the foundation of an external tailings pond is calculated using the lab-measured data. The results show that long-term groundwater monitoring of contaminant transport at the oil sand mining site may be necessary to avoid chemicals from reaching any nearby receptors. PMID:23736740

Wang, Xiaomeng; Robinson, Lisa; Wen, Qing; Kasperski, Kim L

2013-07-01

406

Relationships Between LRI Process Parameters and Impact and Post-Impact Behaviour of Stitched and Unstitched NCF Laminates  

NASA Astrophysics Data System (ADS)

The general context of the development of out-of-autoclave processes in the aeronautics industry raises the question of the possible links between these new processes and impact behaviour. In this study, a Taguchi table was used in a design of experiment approach to establish possible links. The study focused on the liquid resin infusion process applied to laminates made with stitched or unstitched quadri-axial carbon Non-Crimp Fabric (NCF). On the basis of previous studies and an analysis of the literature, five process parameters were selected (stitching, curing temperature, preform position, number of highly porous media, vacuum level). The impact energy was set at 35 J in order to obtain enough residual dent depth. The parameters analysed during and after impact were: maximum displacement of the impactor, energy absorbed, permanent indentation depth, and delaminated surface. Then, compression after impact tests were performed and the corresponding average stress was measured. The interactions found by statistical analysis show a very high sensitivity to stitching, which was, of course, expected. A very significant influence of curing temperature and a significant influence of preform position were also found on the permanent indentation depth and a physical explanation is provided. Globally, it was demonstrated that the resin infusion process itself did not influence the impact behaviour.

Njionhou, Alvine; Berthet, Florentin; Castanié, Bruno; Bouvet, Christophe

2012-12-01

407

Modeling and Analysis of Process Parameters for Evaluating Shrinkage Problems During Plastic Injection Molding of a DVD-ROM Cover  

NASA Astrophysics Data System (ADS)

Plastic injection molding plays a key role in the production of high-quality plastic parts. Shrinkage is one of the most significant problems of a plastic part in terms of quality in the plastic injection molding. This article focuses on the study of the modeling and analysis of the effects of process parameters on the shrinkage by evaluating the quality of the plastic part of a DVD-ROM cover made with Acrylonitrile Butadiene Styrene (ABS) polymer material. An effective regression model was developed to determine the mathematical relationship between the process parameters (mold temperature, melt temperature, injection pressure, injection time, and cooling time) and the volumetric shrinkage by utilizing the analysis data. Finite element (FE) analyses designed by Taguchi (L27) orthogonal arrays were run in the Moldflow simulation program. Analysis of variance (ANOVA) was then performed to check the adequacy of the regression model and to determine the effect of the process parameters on the shrinkage. Experiments were conducted to control the accuracy of the regression model with the FE analyses obtained from Moldflow. The results show that the regression model agrees very well with the FE analyses and the experiments. From this, it can be concluded that this study succeeded in modeling the shrinkage problem in our application.

Öktem, H.

2012-01-01

408

Analysis of process parameter effect on DIBL in n-channel MOSFET device using L27 orthogonal array  

NASA Astrophysics Data System (ADS)

In this research, the effect of the process parameters variation on drain induced barrier lowering (DIBL) was investigated. The fabrication of the transistor device was performed using TCAD simulator, consisting of ATHENA and ATLAS modules. These two modules were combined with Taguchi method to optimize the process parameters. The setting of process parameters was determined by using the orthogonal array of L27 in Taguchi Method. In NMOS device, the most dominant or significant factors for S/N Ratio are halo implant energy, S/D implant dose and S/D implant energy. Meanwhile, the S/N Ratio values of DIBL after the optimization approaches for array L27 is 29.42 dB. In L27 experiments, DIBL value for n-channel MOSFET device after optimizations approaches is +37.8 mV. The results obtained were satisfied to be small as expected. As conclusions, by setting up design of experiment with the Taguchi Method and TCAD simulator, the optimal solutions on DIBL for the robust design recipe of 32nm n-channel MOSFET device was successfully achieved.

Salehuddin, F.; Kaharudin, K. E.; Zain, A. S. M.; Yamin, A. K. Mat; Ahmad, I.

2014-10-01

409

Selection of Wire Electrical Discharge Machining Process Parameters on Stainless Steel AISI Grade-304 using Design of Experiments Approach  

NASA Astrophysics Data System (ADS)

Wire electrical discharge machining (WEDM) is a specialized thermal machining process capable of accurately machining parts of hard materials with complex shapes. Parts having sharp edges that pose difficulties to be machined by the main stream machining processes can be easily machined by WEDM process. Design of Experiments approach (DOE) has been reported in this work for stainless steel AISI grade-304 which is used in cryogenic vessels, evaporators, hospital surgical equipment, marine equipment, fasteners, nuclear vessels, feed water tubing, valves, refrigeration equipment, etc., is machined by WEDM with brass wire electrode. The DOE method is used to formulate the experimental layout, to analyze the effect of each parameter on the machining characteristics, and to predict the optimal choice for each WEDM parameter such as voltage, pulse ON, pulse OFF and wire feed. It is found that these parameters have a significant influence on machining characteristic such as metal removal rate (MRR), kerf width and surface roughness (SR). The analysis of the DOE reveals that, in general the pulse ON time significantly affects the kerf width and the wire feed rate affects SR, while, the input voltage mainly affects the MRR.

Lingadurai, K.; Nagasivamuni, B.; Muthu Kamatchi, M.; Palavesam, J.

2012-06-01

410

Optimization of processing parameters and ingredients for development of low-fat fibre-supplemented paneer.  

PubMed

Increasing demand of low calorie and high fibre containing products give impetus to dairy industry for development of a well palatable low calorie dairy products like paneer. The objective of the present study was to develop low-fat fibre-supplemented paneer. The ingredients were chosen for low-fat fibre- supplemented paneer to reduce the cost and calorie content besides providing the functional benefits. Optimization of ingredients was carried out in terms of independent variables viz wheat bran (0.4-0.8 %), maltodextrin (1-5 %), coagulation temperature (60-80 °C) and amount of citric acid solution (150-210 ml). Response Surface Methodology (RSM) was used to design the experiments and to select the optimum levels of ingredients. Paneer was made by using different levels of ingredients by coagulating hot milk using citric acid solution followed by pressing and dipping in chilled water for texturization. These parameters were evaluated in terms of physico-chemical parameters viz water activity, pH and acidity. Instrumental texture profile analysis (TPA) of paneer during optimization trials was done using TAXT 2i Texture Analyzer. The textural responses namely hardness, adhesiveness, springiness, cohesiveness, gumminess and chewiness were measured via Texture Analyzer. The sensory properties namely flavor, appearance, body and texture, mouth feel and overall acceptability of paneer samples were evaluated by a semi-trained panel of judges using 9-point hedonic scale. Full second order polynomial was developed to predict each response. All the textural and sensory responses were statistically analysed. PMID:25694679

Singh, G; Kumar, A; Kumbhar, B K; Dar, B N

2015-02-01

411

The impact of material attributes and process parameters on the micronisation of lactose monohydrate.  

PubMed

Dry powder inhalers (DPIs), which are important medicines for drug delivery to the lungs, require drug particles in the respirable size range of 1-6 ?m for optimal lung deposition. Drugs administered by the oral route also derive benefit from particles in this size range owing to their large surface area to volume ratio, which provides potential for rapid dissolution. Micronisation used in the production of particles, however often leads to heterogeneous product containing mechanically activated surfaces with amorphous content. This study was therefore carried out to evaluate the effect of particle properties of three grades of lactose monohydrate, with sizes above and below the brittle-ductile transition (dcrit) and their interaction with process variables on the quality of micronised material. Following an experimental design, the impact of three factors (grinding pressure, injector pressure and feed rate) on the particulate attributes of micronised powders produced from the different size grades was assessed. Processing conditions were shown to be important determinants of powder properties only for the coarsest starting material. Ultrafine material was achieved by processing finer grade feed stock below dcrit. However the resultant product was more crystalline and transformed on heating to the anhydrous state with markedly reduced onset temperature with lower energy surfaces than powders produced from larger sized starting material. Thus the propensity for micronisation of lactose monohydrate can be altered through control of starting materials and optimal settings for process variables. PMID:21295125

Shariare, M H; de Matas, M; York, P; Shao, Q

2011-04-15

412

Optimal Process Control Parameters Estimation in Aluminium Extrusion for Given Product Characteristics  

Microsoft Academic Search

This paper investigates a technique to nd an optimal set of conditions for an isothermal process to extrude a product for a given shape and material properties with minimal defects. The inputs to this model are: the product geometry and its mate- rial data such as o w curve and microstructure during dynamic recrystallization. This is an inverse problem and

P. Kathirgamanathan; T. Neitzert

413

Motion compensated image processing and optimal parameters for egg crack detection using modified pressure  

Technology Transfer Automated Retrieval System (TEKTRAN)

Shell eggs with microcracks are often undetected during egg grading processes. In the past, a modified pressure imaging system was developed to detect eggs with microcracks without adversely affecting the quality of normal intact eggs. The basic idea of the modified pressure imaging system was to ap...

414

Effect of process parameters on the production of lactic acid bacteria in batch fermentation  

Microsoft Academic Search

The effect of aeration and type of neutralising agent on the growth of lactic acid bacteria, isolated from a typical Italian cheese, was investigated in laboratory fermenters, with the aim of defining process conditions for the production of autochthonous cul- tures to be used as starters in traditional cheese-making. Batch fermentation trials were carried out using six different bacterial species

Emanuele ZANNINI; Sara SANTARELLI; Andrea OSIMANI; Luana DELL' AQUILA; Francesca CLEMENTI

415

Study of sponge cake batter baking process. II. Modeling and parameter estimation  

Microsoft Academic Search

A 1D model for heat and mass transfer within a sponge cake batter during a baking process, based on the qualitative analysis of the transfer mechanisms reported in part I of this paper, is presented. With respect to previous literature reports concerning cake baking modeling, the model takes additionally into account the gas phase internal convective flux, the vapo-condensation heat

Mathieu Lostie; Roman Peczalski; Julien Andrieu; Michel Laurent

2002-01-01

416

Signal Processing 88 (2008) 339348 Estimation of slowly varying parameters in nonlinear systems  

E-print Network

that, in turn, are used to construct a special class of probabilistic finite state automata (PFSA of finite state automata, pattern recognition, and information theory, and relies on the following two basic as a Markov process on a finite- dimensional state space, SDF is constructed as a finite state automaton

Ray, Asok

417

The correlations between processing parameters and magnetic properties of an iron–resin soft magnetic composite  

Microsoft Academic Search

In this study, internal microstrain of an iron–resin composite produced by powder metallurgy has been calculated using the Williamson–Hall method. The effects of microstrain evolution during different processing conditions on magnetic properties such as coercive force and hysteresis loss have been investigated. The results show that there are regular and similar changes of coercivity and hysteresis loss. Both of these

I. Hemmati; H. R. Madaah Hosseini; A. Kianvash

2006-01-01

418

Process Parameters and Energy Use of Gas and Electric Ovens in Industrial Applications  

E-print Network

The study was conducted to evaluate the energy use of natural gas and electric ovens in the production of polymer bearings and components. Tests were conducted to evaluate and compare the performance of natural gas and electric ovens in the process...

Kosanovic, D.; Ambs, L.

419

Adaptive hybrid optimization strategy for calibration and parameter estimation of physical process models  

NASA Astrophysics Data System (ADS)

A new adaptive hybrid optimization strategy, entitled squads, is proposed for complex inverse analysis of computationally intensive physics-based models. Typically, models are calibrated and model parameters are estimated by minimization of the discrepancy between model simulations characterizing the system and existing observations requiring a substantial number of model evaluations. Squads is designed to be computationally efficient and robust in identification of the global optimum (i.e. maximum or minimum value of an objective function). It integrates global and local optimization using Adaptive Particle Swarm Optimization (APSO) and Levenberg-Marquardt (LM) optimization using adaptive rules based on runtime performance. The global strategy (APSO) optimizes the location of a set of solutions (particles) in the parameter space. The local strategy (LM) is applied only to a subset of the particles at different stages of the optimization based on the adaptive rules. After the LM adjustment of the subset of particle positions, the updated particles are returned to APSO. Therefore, squads is a global strategy that utilizes a local optimization speedup. The advantages of coupling APSO and LM in the manner implemented in squads is demonstrated by comparisons of squads performance against Levenberg-Marquardt (LM), Particle Swarm Optimization (PSO), Adaptive Particle Swarm Optimization (APSO; i.e. TRIBES), and an existing hybrid optimization strategy (hPSO). All the strategies are tested on 2D, 5D and 10D Rosenbrock and Griewank polynomial test functions and a synthetic hydrogeologic application to identify the source of a contaminant plume in an aquifer. Tests are performed using a series of runs with random initial guesses for the estimated parameters. The performance of the strategies are compared based on their robustness, defined as the percentage of runs that identify the global optimum, and their efficiency, quantified by a statistical representation of the number of function evaluations performed prior to identification of the global optimum. Squads is observed to have better performance than the other strategies for the test functions and the hydrogeologic application when both robustness and efficiency are taken into consideration.

Vesselinov, Velimir V.; Harp, Dylan R.

2012-12-01

420

Scientific predictability of solid rocket performance: Analyses of the processing parameters  

NASA Astrophysics Data System (ADS)

The objective is to present a computational model of the suspensions composing uncured composite solid propellant. Highly concentrated suspensions of more than 50 pct. solid volume were examined with attendence to bimodal mixtures. Study of propellant processing was conducted to determine how this model can be applied to processing. Experimental work was conducted to supply data for comparison to the computational results. This involved data gathered from an orifice viscometer on viscosity and flow behavior. This model is a tool to study goodness of mixing throughout the processing stages of the propellant. The study into processing focused both on mixing and casting of the suspension. By studying this model for concentration, velocity and thermal behaviors, a better understanding of how well the propellant composition progresses in processing was obtained. A multiple mixture approach was taken. This involved a continuum description for the mixture and each constituent. A Fortran program was written to construct this routine. It was run on both a VAXstation 3100, Model 40 using VMS Digital operating system, and a SUN IPX, using SUN UNIX operating system. The code examined two-dimensional monomodal and bimodal mixture flows through a pipe. It examined concentration between 65 and 75 pcts. Due to the high concentration, it was necessary to apply all inertial and viscous terms within each constituent and the entire mixture. Proper boundary conditions and initial conditions to produce stable runs were found. Both monomodal and biomodal computational results showed good correlations with the experimental data, although a slight dilatation was produced by the program. No dilatation appeared in the experimental work.

Perez, Daniel Lizarraga

421

Identification of sensitive parameters in the modeling of SVOCs reemission processes from soil to atmosphere  

NASA Astrophysics Data System (ADS)

Many studies have shown that semi-volatile organic compounds (SVOCs) are subject to Long-Range Atmospheric Transport (LRAT) and that such a transport may occur through a series of deposition-reemission events at the soil surface-air interface. This periodic movement of pollutants between soil and atmosphere is called the 'grasshopper effect'. Thus, it appears necessary to take into account the exchange between soil and atmosphere to properly simulate the fate of these pollutants at regional or global scale. The prediction of reemission from soils is however associated with large uncertainties, which can be schematically classified into three main sources : (i) natural variability, including nature of soil (organic matter content, porosity, water content) and meteorological conditions ; (ii) uncertainty about intrinsic properties of chemicals, like degradation rate or partitioning between environmental components, which govern the dynamics of chemicals in air and soils ; (iii) model structure, and particularly the discretization of soil compartment. Considering this background, a major challenge is to identify the most sensitive sources of uncertainty in modelling the reemission of chemicals from soils, in order to know where the priority has to be set for upgrading SVOC dispersion estimation. To answer this question, we studied a multi-layer soil model, including exchanges between soil and atmosphere. A sensitivity analysis was conducted by affecting probability density functions for each of model parameters. Four chemicals were selected (Benzo(a)Pyrene, PCB-28, Lindane and Hexachlorobenzene) because of their contrasted behaviors in soils, as expected by their partition and degradation properties. For this first exercise, simple emission scenarii were considered, i.e. a period of constant concentration in air (where realistic concentrations were estimated for each chemical from monitoring data provided by EMEP) followed by a zero-concentration in air. Although these scenarii are obviously simplified, they were selected to identify sensitive parameters in two extreme conditions, i.e. constant emission in the atmosphere over a long period, and follow-up of ban regulation. Results show that the rank of sensitive parameters depends on the intrinsic properties of the investigated substances, in particular on their mobility potential in soils and their ability to volatilize. Despite such differences, general patterns can however be observed: for all the substances, organic matter content in the soil is one of the most sensitive parameters in the simulation of reemission fluxes in both contamination conditions (i.e. charge and discharge periods). Instead, the number of layers used in the model for simulating the transfer of pollutants in the soil profile is less influential. These results allowed defining priorities in LRAT modeling strategy, highlighting in particular that mapping organic matter in soils instead of using a generic value could significantly improve the reemission estimation.

Loizeau, Vincent; Ciffroy, Philippe; Musson Genon, Luc; Roustan, Yelva

2013-04-01

422

Stevia rebaudiana Bertoni as a natural antioxidant/antimicrobial for high pressure processed fruit extract: processing parameter optimization.  

PubMed

Response surface methodology was used to evaluate the optimal high pressure processing treatment (300-500 MPa, 5-15 min) combined with Stevia rebaudiana (Stevia) addition (0-2.5% (w/v)) to guarantee food safety while maintaining maximum retention of nutritional properties. A fruit extract matrix was selected and Listeria monocytogenes inactivation was followed from the food safety point of view while polyphenoloxidase (PPO) and peroxidase (POD) activities, total phenolic content (TPC) and antioxidant capacity (TEAC and ORAC) were studied from the food quality point of view. A combination of treatments achieved higher levels of inactivation of L. monocytogenes and of the oxidative enzymes, succeeding in completely inactivating POD and also increasing the levels of TPC, TEAC and ORAC. A treatment of 453 MPa for 5 min with a 2.5% (w/v) of Stevia succeeded in inactivating over 5 log cycles of L. monocytogenes and maximizing inactivation of PPO and POD, with the greatest retention of bioactive components. PMID:24262555

Barba, Francisco José; Criado, María Nieves; Belda-Galbis, Clara Miracle; Esteve, María José; Rodrigo, Dolores

2014-04-01

423

Some Working Parameters and Energy Use in a Pistachio Nut Processing Plant: A Case Study  

NASA Astrophysics Data System (ADS)

This study was performed with the objective to investigate the work process, work capacity, work effectiveness, energy consumption and labor force requirements of basic units such as washing, dehulling, sorting, separating, roasting and packing in a pistachio processing plant which has been mechanized in the last years. As a result of this study, the work capacity in washing, sorting, breaking, drying, separating units was found to be 1.5, 1.5, 2, 1, 1.6 t h-1, respectively. The work effectiveness in sorting and breaking units was found to be 95% and that of separating unit was 99%. The total energy consumption of the units was found to be 20.42 kW h-1 and the total labor force requirement was found to be five workers.

Polat, Refik; Erol Ak, Bekir; Acar, Izzet

424

Photochemical degradation of ciprofloxacin in UV and UV/H?O? process: kinetics, parameters, and products.  

PubMed

Photochemical degradation of fluoroquinolone ciprofloxacin (CIP) in water by UV and UV/H?O? were investigated. The degradation rate of CIP was affected by pH, H?O? dosage, as well as the presence of other inorganic components. The optimized pH value and H?O? concentration were 7.0 and 5 mM. Carbonate and nitrate both impeded CIP degradation. According to liquid chromatography-tandem mass spectrometry analysis, four and 16 products were identified in UV and UV/H?O? system, respectively. Proposed degradation pathways suggest that reactions including the piperazinyl substituent, quinolone moiety, and cyclopropyl group lead to the photochemical degradation of CIP. Toxicity of products assessed by Vibrio qinghaiensis demonstrated that UV/H?O? process was more capable on controlling the toxicity of intermediates in CIP degradation than UV process. PMID:23054793

Guo, Hong-Guang; Gao, Nai-Yun; Chu, Wen-Hai; Li, Lei; Zhang, Yong-Ji; Gu, Jin-Shan; Gu, Yu-Liang

2013-05-01

425

Influence of Punch Geometry on Process Parameters in Cold Backward Extrusion  

NASA Astrophysics Data System (ADS)

In cold extrusion of steel tools make direct contact with the metal to be extruded. Those tools are exposed to high contact stresses which, in certain cases, may be limiting factors in applying this technology. The present paper was bound to the influence of punch head design on radial stress at the container wall in the process of cold backward extrusion. Five different punch head geometries were investigated. Radial stress on the container wall was measured by pin load cell technique. Special tooling for the experimental investigation was designed and made. Process has been analyzed also by FE method. 2D models of tools were obtained by UGS NX and for FE analysis Simufact Forming GP software was used. Obtained results (experimental and obtained by FE) were compared and analyzed. Optimal punch head geometry has been suggested.

Plan?ak, M.; Bariši?, B.; Car, Z.; Movrin, D.

2011-01-01

426

Influence of process parameters during pulsed Nd:YAG laser cutting of nickel-base superalloys  

Microsoft Academic Search

Although CO2 lasers have been widely employed for commercial sheet metal cutting operations, increased recognition of the processing benefits afforded by pulsed Nd:YAG lasers has recently fuelled interest in the latter. Pulsed Nd:YAG laser cutting differs from conventional continuous wave laser cutting as it involves overlapping of a series of individual spots generated by each pulse. In this paper, a

G. Thawari; J. K. Sarin Sundar; G. Sundararajan; S. V. Joshi

2005-01-01

427

Dry Matter Loss During Nixtamalization of a White Corn Hybrid: Impact of Processing Parameters  

Microsoft Academic Search

Cereal Chem. 77(2):254-258 Nixtamalization is the primary step in the production of products such as corn chips, tortilla chips, tacos, and corn tortillas. The process involves cooking and steeping of corn in lime and excess water to produce nixta- mal. Commercial nixtamalization results in 5-14% corn solids loss in the liquid generated during cooking-steeping and washing. Loss of corn solids

D. Sahai; I. Surjewan; J. P. Mua; M. O. Buendia; M. Rowe; D. S. Jackson

2000-01-01

428

Chemical and petroleum and gas processing plant selection of certain parameters for designing sublimation facilities  

SciTech Connect

One of the promising methods of obtaining the ultradisperse powders used in industry is the sublimation method. The authors attempt to establish the relation between the product dispersion and the processing conditions, and to construct on this basis a method of designing sublimation plants with direct introduction of the solution into a vacuum. The study is made for single component aqueous salt solutions having concentrations less than eutectic.

Brazhnikov, S.M.; Serova, L.A.; Karabanov, A.V.

1987-11-01

429

The effect of processing parameters on oil content of corn tortilla chips  

E-print Network

and oil content of chips during the frying process . . . 4 - Relationship between moisture content of tortilla pieces before 39 frying and oil content of tortilla chips 44 5 - Relationship between moisture content of tortilla pieces dried at 50'C... before frying and oil content of tortilla chips 46 6 - Relationship between moisture content of tortilla pieces dried at 60'C before frying and oil content of tortilla chips. . . . . . . . 7 - Relationship between moisture content of tortilla pieces...

Dudley, Peta Rock

1993-01-01

430

Characterization of residual stresses in heat treated Ti-6Al-4V forgings by machining induced distortion  

NASA Astrophysics Data System (ADS)

To provide a solid base for improved material exploitation in dimensioning calculations it is necessary to determine the stress state in the part prior to service loading. In order to achieve higher material strength at elevated temperatures, the surface temperature gradient with respect to time has to be sufficiently high during heat treatment. This results in non-negligable residual stresses that can reduce the allowable load level upon which yielding occurs. For titanium alloys there are two common heat treatments, namely solution treatment and mill annealing. The latter one is the method of choice within the presented project. Mill annealing is utilized in order to significantly reduce the residual stresses in the parts without loosing much of the improved strength at elevated temperatures. Quantification of residual stresses is done by solving an inverse problem. From the measurement of distortion, induced by dividing the investigated part, the residual stress state can be calculated via analytical modeling or correlation with finite element models. To assure a minimum perturbation of the residual stress state during specimen production, dividing of the part is accomplished by electric discharge machining. The parts of interest are v-shaped prisms with a length of approximatly 450 mm and a thickness in the cross sectional area from about 20 mm to 45 mm. Figure 1(a) shows the forged part and 1(b) the dimensions of the cross section in millimeters as well as the material properties considered in the finite element model. The heat exchange between the part and the environment is modelled as heat transfer by convection superimposed with heat radiation. Since the parts are exposed to air during forging and heat treatment, the surface develops a strongly adhesive oxide layer, the so called alpha-case. After forging the parts are cooled in air and heat treated at a temperature of 720° C for a duration of 120 min. Subsequent air cooling and removing the alpha-case by shot peening and chemical treatment in a mixture of nitric and hydroflouric acid finishes the processing. The residual stress state in the parts is quantified through correlation of results obtained by finite element simulations and high precision deflection experiments. Experimental measuring errors are minimized by using the capability of the wire cutting machine to measure locations on the specimens with respect to the fixed machine coordinate system. A sophisticated design of cutting operations allows an analysis of the part without removing the fixture and hence makes it possible to achieve a very high accuracy of the displacement measurements of about 4 µm. The quality of the obtained results also depends on the finite element models describing the mechanics of the experimental investigations as precise as possible. Since numerical modeling of shot peening and chemical milling is rather complicated, the whole processing route of the shapes is simplified assuming that the individual contribution of all process steps to the residual stress state can be described by virtual heat transfer coefficients. The overall virtual heat transfer coefficient for the whole processing route is calculated from the linear superposition of the individual heat transfer coeffcients for each processing step. Detailed analysis of the obtained overall virtual heat transfer coefficients in comparison with experimentally obtained ones shows, that other processing steps besides the heat treatment considerably influence the residual stress state. In order to make the conducted simulation scheme applicable in practise, advanced finite element modeling techniques are developed. The experimentally derived deflection curves are correlated to the finite element results via a least square fit.

Regener, B.; Krempaszky, C.; Werner, E.

2010-06-01

431

Liquefaction of lignocellulosic biomass: solvent, process parameter, and recycle oil screening.  

PubMed

The liquefaction of lignocellulosic biomass is studied for the production of liquid (transportation) fuels. The process concept uses a product recycle as a liquefaction medium and produces a bio-oil that can be co-processed in a conventional oil refinery. This all is done at medium temperature (? 300 °C) and pressure (? 60 bar). Solvent-screening experiments showed that oxygenated solvents are preferred as they allow high oil (up to 93% on carbon basis) and low solid yields (? 1-2% on carbon basis) and thereby outperform the liquefaction of biomass in compressed water and biomass pyrolysis. The following solvent ranking was obtained: guaiacol>hexanoic acid ? n-undecane. The use of wet biomass results in higher oil yields than dry biomass. However, it also results in a higher operating pressure, which would make the process more expensive. Refill experiments were also performed to evaluate the possibility to recycle the oil as the liquefaction medium. The recycled oil appeared to be very effective to liquefy the biomass and even surpassed the start-up solvent guaiacol, but became increasingly heavy and more viscous after each refill and eventually showed a molecular weight distribution that resembles that of refinery vacuum residue. PMID:24265195

van Rossum, Guus; Zhao, Wei; Castellvi Barnes, Maria; Lange, Jean-Paul; Kersten, Sascha R A

2014-01-01

432

Influence of Processing Parameters on Induced Energy, Mechanical and Corrosion Properties of FSW Butt Joint of 7475 AA  

NASA Astrophysics Data System (ADS)

Friction stir welding (FSW), a promising solid state joining process invented at TWI in 1991, was used to join 9 mm thick 7475 aluminum alloy which is considered essentially unweldable by fusion processes. In the present work, the process parameters such as tool rotational speed were varied from 300 to 1000 rpm for a travel speed of 50 mm/min and the influence of process parameters in terms of energy input on microstructure, hardness, tensile strength, and the corrosion property of 7475 aluminum joints was evaluated and analyzed. The maximum tensile strength of FSW joints was obtained at rotational speed of 400 rpm and traverse speed of 50 mm/min (59.2 kJ) which attributed maximum stirred zone area and maximum hardness. The maximum corrosion resistance properties of weld in 3.5% NaCl solution, however, were obtained at rotational speed of 1000 rpm and traverse speed of 50 mm/min. Furthermore, for a given weld, stirred zone showed improved corrosion properties than TMAZ.

Gupta, Rajesh Kumar; Das, Hrishikesh; Pal, Tapan Kumar

2012-08-01

433

Validation of cresis synthetic aperture radar processor and optimal processing parameters  

NASA Astrophysics Data System (ADS)

Sounding the ice sheets of Greenland and Antarctica is a vital component in determining the effect of global warming on sea level rise. Of particular importance are measurements of the bedrock topography of the outlet glaciers that transport ice from the ice sheet's interior to the margin where it calves into icebergs, contributing to sea level rise. These outlet glaciers are difficult to sound due to crevassing caused by the relatively fast movement of the ice in the glacial channel and higher signal attenuation caused by warmer ice. The Center for Remote Sensing of Ice Sheets (CReSIS) uses multi-channel airborne radars which employ methods for achieving better resolution and signal-to-noise ratio (SNR) to better sound outlet glaciers. Synthetic aperture radar (SAR) techniques are used in the along-track dimension, pulse compression in the range dimension, and an antenna array in the cross-track dimension. CReSIS has developed the CReSIS SAR processor (CSARP) to effectively and efficiently process the data collected by these radars in each dimension. To validate the performance of this processor a SAR simulator was developed with the functionality to test the implementation of the processing algorithms in CSARP. In addition to the implementation of this simulator for validation of processing the data in the along-track, cross-track and range dimensions, there are a number of data-dependent processing steps that can affect the quality of the final data product. CSARP was tested with an ideal simulated point target in white Gaussian noise. The SNR change achieved by range compression, azimuth compression, array combination with and without matched filtering, and lever arm application were all within .2 dB of the theoretical expectation. Channel equalization, when paired with noise-based matched filtering, provided 1-2 dB of gain on average but significantly less than the expected gain. Extending the SAR aperture length to sound bedrock will improve the along-track resolution, but at the expense of SNR. Increasing the taper of a window in the fast-time and slow-time will slightly improve the SNR of the data. Changing the relative permittivity used to process the data improved the resulting SNR by no more than 0.025 dB for the test dataset.

Smith, Logan Sanders

434

Hyperspectral Data Processing and Mapping of Soil Parameters: Preliminary Data from Tuscany (Italy)  

NASA Astrophysics Data System (ADS)

Hyperspectral imaging has become a very powerful remote sensing tool for its capability of performing chemical and physical analysis of the observed areas. The objective of this study is to retrieve and characterize clay mineral content of the cultivated layer of soils, from both airborne hyperspectral and field spectrometry surveys in the 400-2500 nm spectral range. Correlation analysis is used to examine the possibility to predict the selected property using high-resolution reflectance spectra and images. The study area is located in the Mugello basin, about 30 km north of Firenze (Tuscany, Italy). Agriculturally suitable terrains are assigned mainly to annual crops, marginally to olive groves, vineyards and orchards. Soils mostly belong to Regosols and Cambisols orders. About 80 topsoil samples scattered all over the area were collected simultaneously with the flight of SIM.GA hyperspectral camera from Selex Galileo. The quantitative determination of clay minerals content in soil samples was performed by means of XRD and Rietveld refinement. An ASD FieldSpec spectroradiometer was used to obtain reflectance spectra from dried, crushed and sieved samples under controlled laboratory conditions. Different chemometric techniques (multiple linear regression, vertex component analysis, partial least squares regression and band depth analysis) were preliminarily tested to correlate mineralogical records with reflectance data. A one component partial least squares regression model yielded a preliminary R2 value of 0.65. A similar result was achieved by plotting the absorption peak depth at 2210 versus total clay mineral content (band-depth analysis). A complete hyperspectral geocoded reflectance dataset was collected using SIM.GA hyperspectral image sensor from Selex-Galileo, mounted on board of the University of Firenze ultra light aircraft. The approximate pixel resolution was 0.6 m (VNIR) and 1.2 m (SWIR). Airborne SIM.GA row data were firstly transformed into at-sensor radiance values, where calibration coefficients and parameters from laboratory measurements are applied to non-georeferred VNIR/SWIR DN values. Then, geocoded products are retrieved for each flight line by using a procedure developed in IDL Language and PARGE (PARametric Geocoding) software. When all compensation parameters are applied to hyperspectral data or to the final thematic map, orthorectified, georeferred and coregistered VNIR to SWIR images or maps are available for GIS application and 3D view. Airborne imagery has to be corrected for the influence of the atmosphere, solar illumination, sensor viewing geometry and terrain geometry information, for the retrieval of inherent surface reflectance properties. Then, different geophysical parameters can be investigated and retrieved by means of inversion algorithms. The experimental fitting of laboratory data on mineral content is used for airborne data inversion, whose results are in agreement with laboratory records, demonstrating the possibility to use this methodology for digital mapping of soil properties.

Garfagnoli, F.; Moretti, S.; Catani, F.; Innocenti, L.; Chiarantini, L.

2010-12-01

435

CO2 laser cutting: analytical dependence of the roughness of the cut edge on the experimental parameters and process monitoring  

NASA Astrophysics Data System (ADS)

Over the last few years laser cutting has been widely introduced in industrial production lines, mainly due to the high processing speeds. In the present work a fundamental aspect of the cutting process of metals has been considered: the formation of periodic striations on the cut edge that greatly affects the quality of the treated samples. Therefore this paper is devoted to the study of the roughness of the cut surfaces with a particular attention to the dependence of this parameters on the working conditions. For a better understanding of the variables involved in the process, a comparison of the experimental data with the results of an analytical model has been performed. Furthermore a real time monitoring of the infrared emission coming from the interaction zone has been carried out by means of an electrooptic device properly developed for the measurements of the local temperature. A correlation between these data and the roughness measurements has been found.

Sforza, Patrizia; Santacesaria, Vincenzo

1994-09-01

436

The effects of process parameters on yield and properties of iron nanoparticles from ferrocene in a low-pressure plasma  

NASA Astrophysics Data System (ADS)

The effects of process parameters on iron nanoparticle formation and properties while using ferrocene as a precursor in a low-pressure capacitively coupled plasma are investigated. The L18 array of the Taguchi method, followed by the L4 array, is used with the notional objective of increasing the yield of nanoparticles. A study of the size, shape and composition of the particles (using transmission electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, x-ray diffraction, CHON and inductively coupled plasma-atomic emission spectroscopy analysis) gives an insight into the role played by various process parameters. Pressure is the most critical parameter in increasing nanoparticle yield, whereas hydrogen flow plays a key role in determining the nanoparticle size and composition. Atomic hydrogen helps in removing amorphous carbon and reducing the nanoparticle size. RF power plays an important role in the dissociation of ferrocene thus also affecting the composition. Nanoparticles obtained using optimized conditions are a mixture of Fe3O4 and Fe2O3 with cluster size 25-40 nm in diameter that are further made up of 2-4 nm crystallites. Magnetic property measurements indicate that the nanoparticles are super-paramagnetic in nature.

Panchal, V.; Lahoti, G.; Bhandarkar, U.; Neergat, M.

2011-08-01

437

Exploring the effects of pulsed electric field processing parameters on polyacetylene extraction from carrot slices.  

PubMed

The effects of various pulsed electric field (PEF) parameters on the extraction of polyacetylenes from carrot slices were investigated. Optimised conditions with regard to electric field strength (1-4 kV/cm), number of pulses (100-1500), pulse frequency (10-200 Hz) and pulse width (10-30 ?s) were identified using response surface methodology (RSM) to maximise the extraction of falcarinol (FaOH), falcarindiol (FaDOH) and falcarindiol-3-acetate (FaDOAc) from carrot slices. Data obtained from RSM and experiments fitted significantly (p < 0.0001) the proposed second-order response functions with high regression coefficients (R2) ranging from 0.82 to 0.75. Maximal FaOH (188%), FaDOH (164.9%) and FaDOAc (166.8%) levels relative to untreated samples were obtained from carrot slices after applying PEF treatments at 4 kV/cm with 100 number of pulses of 10 ?s at 10 Hz. The predicted values from the developed quadratic polynomial equation were in close agreement with the actual experimental values with low average mean deviations (E%) ranging from 0.68% to 3.58%. PMID:25738537

Aguiló-Aguayo, Ingrid; Abreu, Corina; Hossain, Mohammad B; Altisent, Rosa; Brunton, Nigel; Viñas, Inmaculada; Rai, Dilip K

2015-01-01

438

Effect of Breadmaking Process on In Vitro Gut Microbiota Parameters in Irritable Bowel Syndrome  

PubMed Central

A variety of foods have been implicated in symptoms of patients with Irritable Bowel Syndrome (IBS) but wheat products are most frequently cited by patients as a trigger. Our aim was to investigate the effects of breads, which were fermented for different lengths of time, on the colonic microbiota using in vitro batch culture experiments. A set of in vitro anaerobic culture systems were run over a period of 24 h using faeces from 3 different IBS donors (Rome Criteria–mainly constipated) and 3 healthy donors. Changes in gut microbiota during a time course were identified by fluorescence in situ hybridisation (FISH), whilst the small -molecular weight metabolomic profile was determined by NMR analysis. Gas production was separately investigated in non pH-controlled, 36 h batch culture experiments. Numbers of bifidobacteria were higher in healthy subjects compared to IBS donors. In addition, the healthy donors showed a significant increase in bifidobacteria (P<0.005) after 8 h of fermentation of a bread produced using a sourdough process (type C) compared to breads produced with commercial yeasted dough (type B) and no time fermentation (Chorleywood Breadmaking process) (type A). A significant decrease of ?-Proteobacteria and most Gemmatimonadetes species was observed after 24 h fermentation of type C bread in both IBS and healthy donors. In general, IBS donors showed higher rates of gas production compared to healthy donors. Rates of gas production for type A and conventional long fermentation (type B) breads were almost identical in IBS and healthy donors. Sourdough bread produced significantly lower cumulative gas after 15 h fermentation as compared to type A and B breads in IBS donors but not in the healthy controls. In conclusion, breads fermented by the traditional long fermentation and sourdough are less likely to lead to IBS symptoms compared to bread made using the Chorleywood Breadmaking Process. PMID:25356771

Costabile, Adele; Santarelli, Sara; Claus, Sandrine P.; Sanderson, Jeremy; Hudspith, Barry N.; Brostoff, Jonathan; Ward, Jane L.; Lovegrove, Alison; Shewry, Peter R.; Jones, Hannah E.; Whitley, Andrew M.; Gibson, Glenn R.

2014-01-01

439

Effect of breadmaking process on in vitro gut microbiota parameters in irritable bowel syndrome.  

PubMed

A variety of foods have been implicated in symptoms of patients with Irritable Bowel Syndrome (IBS) but wheat products are most frequently cited by patients as a trigger. Our aim was to investigate the effects of breads, which were fermented for different lengths of time, on the colonic microbiota using in vitro batch culture experiments. A set of in vitro anaerobic culture systems were run over a period of 24 h using faeces from 3 different IBS donors (Rome Criteria-mainly constipated) and 3 healthy donors. Changes in gut microbiota during a time course were identified by fluorescence in situ hybridisation (FISH), whilst the small-molecular weight metabolomic profile was determined by NMR analysis. Gas production was separately investigated in non pH-controlled, 36 h batch culture experiments. Numbers of bifidobacteria were higher in healthy subjects compared to IBS donors. In addition, the healthy donors showed a significant increase in bifidobacteria (P<0.005) after 8 h of fermentation of a bread produced using a sourdough process (type C) compared to breads produced with commercial yeasted dough (type B) and no time fermentation (Chorleywood Breadmaking process) (type A). A significant decrease of ?-Proteobacteria and most Gemmatimonadetes species was observed after 24 h fermentation of type C bread in both IBS and healthy donors. In general, IBS donors showed higher rates of gas production compared to healthy donors. Rates of gas production for type A and conventional long fermentation (type B) breads were almost identical in IBS and healthy donors. Sourdough bread produced significantly lower cumulative gas after 15 h fermentation as compared to type A and B breads in IBS donors but not in the healthy controls. In conclusion, breads fermented by the traditional long fermentation and sourdough are less likely to lead to IBS symptoms compared to bread made using the Chorleywood Breadmaking Process. PMID:25356771

Costabile, Adele; Santarelli, Sara; Claus, Sandrine P; Sanderson, Jeremy; Hudspith, Barry N; Brostoff, Jonathan; Ward, Jane L; Lovegrove, Alison; Shewry, Peter R; Jones, Hannah E; Whitley, Andrew M; Gibson, Glenn R

2014-01-01

440

Processing and flammability parameters of bismaleimide and some other thermally stable resin matrices for composites  

NASA Technical Reports Server (NTRS)

The effect of processing variables on the flammability and mechanical properties of state-of-the-art and advanced resin matrices for graphite composites were studied. Resin matrices which were evaluated included state-of-the-art epoxy, phenolic-novolac, phenolic-Xylok, two types of bismaleimides, benzyl, polyethersulfone, and polyphenylsulfone. Comparable flammability and thermochemical data on graphite-reinforced laminates prepared with these resin matrices are presented, and the relationship of some of these properties to the anaerobic char yield of the resins is described.

Kourtides, D. A.

1984-01-01

441

Influence of initial composition and processing parameters on the critical current density of BPSCCO pit tapes  

SciTech Connect

Studies on bulk and Ag sheathed tapes of BPSCCO superconducting materials have been conducted. The results show that Bi{sub 1.8}Pb{sub 0.4}Sr{sub 2}Ca{sub 2.2}Cu{sub 3}O{sub y} prepared through the sol-gel process and vacuum calcined under O{sub 2}-rich dynamic flow conditions give most favorable results. Importance of AC susceptibility (x{prime})-temperature (T) measurements became evident in evaluating the quality of the tapes.

Damodaran, A.D.; Warrier, K.G.K.; Mukherjee, P.S.; Mani, T.V.; Sarma, M.S.; Augustine, S. [Regional Research Lab., Trivandrum (India); Swaminathan, G.; Venugopal, K.; Dhananjayan, M.V.T. [BHEL, Hyderabad (India)

1994-12-31

442

Effect of process parameters on temperature distribution in twin-electrode TIG coupling arc  

NASA Astrophysics Data System (ADS)

The twin-electrode TIG coupling arc is a new type of welding heat source, which is generated in a single welding torch that has two tungsten electrodes insulated from each other. This paper aims at determining the distribution of temperature for the coupling arc using the Fowler-Milne method under the assumption of local thermodynamic equilibrium. The influences of welding current, arc length, and distance between both electrode tips on temperature distribution of the coupling arc were analyzed. Based on the results, a better understanding of the twin-electrode TIG welding process was obtained.

Zhang, Guangjun; Xiong, Jun; Gao, Hongming; Wu, Lin

2012-10-01

443

Influence of process parameters on properties of reactively sputtered tungsten nitride thin films  

SciTech Connect

Tungsten nitride (WN{sub x}) thin films were produced by reactive dc magnetron sputtering of tungsten in an Ar-N{sub 2} gas mixture. The influence of the deposition power on the properties of tungsten nitride has been analyzed and compared with that induced by nitrogen content variation in the sputtering gas. A combined analysis of structural, electrical and optical properties on thin WN{sub x} films obtained at different deposition conditions has been performed. It was found that at an N{sub 2} content of 14% a single phase structure of W{sub 2}N films was formed with the highest crystalline content. This sputtering gas composition was subsequently used for fabricating films at different deposition powers. Optical analysis showed that increasing the deposition power created tungsten nitride films with a more metallic character, which is confirmed with resistivity measurements. At low sputtering powers the resulting films were crystalline whereas, with an increase of power, an amorphous phase was also present. The incorporation of an excess of nitrogen atoms resulted in an expansion of the W{sub 2}N lattice and this effect was more pronounced at low deposition powers. Infrared analysis revealed that in WN{sub x} films deposited at low power, chemisorbed N{sub 2} molecules did not behave as ligands whereas at high deposition power they clearly appeared as ligands around metallic tungsten. In this study, the influence of the most meaningful deposition parameters on the phase transformation reaction path was established and deposition conditions suitable for producing thermally stable and highly crystalline W{sub 2}N films were found.

Addonizio, Maria L.; Castaldo, Anna; Antonaia, Alessandro; Gambale, Emilia; Iemmo, Laura [ENEA, Portici Research Centre, Piazzale E. Fermi 1, I-80055, Portici (Italy)

2012-05-15

444

Continuous-wave fiber laser cutting of aluminum thin sheets: effect of process parameters and optimization  

NASA Astrophysics Data System (ADS)

One-millimeter-thick Al 1050 sheets were cut using a 2-kW fiber laser operating in continuous-wave (CW) mode. An experimental approach that consisted of fitting the regression models by means of response surface methodology was adopted. The effects of cutting speed, assist gas pressure, and focal position on roughness arithmetic mean value were investigated. The desirability function was applied for the simultaneous optimization of cut quality and operating costs. The full potential of the CW mode high processing speeds and of the better absorptivity of 1-?m laser radiation for highly reflective materials are employed at the same time. Cutting aluminum with fiber laser increases the cutting speed and gives a cut quality comparable with results obtained with CO2 and Nd:YAG lasers that represent the most established laser sources for this application.

Scintilla, Leonardo Daniele

2014-06-01

445

Numerical Study of In-flight Particle Parameters in Low-Pressure Cold Spray Process  

NASA Astrophysics Data System (ADS)

A 2-D model of the low-pressure cold spray with a radial powder feeding was established using CFD software in this study. The flow field was simulated for both propellant gases of nitrogen and helium. To predict the in-flight particle velocity and temperature, discrete phase model was introduced to simulate the interaction of particle and the supersonic gas jet. The experimental velocity of copper powder with different sizes was used to validate the calculated one for low-pressure cold spray process. The results show that the computational model can provide a satisfactory prediction of the supersonic gas flow, which is consistent with the experimental Schlieren photos. It was found that similar velocity was obtained with the drag coefficient formula of Henderson and with that of Morsi and Alexander. As the shape factor was estimated, the reasonable prediction of velocity for non-spherical particle can be obtained, to compare with the experimental results.

Ning, Xian-Jin; Wang, Quan-Sheng; Ma, Zhuang; Kim, Hyung-Jun

2010-12-01