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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

Effects of Forging Process Parameters on Microstructure Evolution of Aluminum Alloy 7050  

SciTech Connect

The objective of this work is to investigate the behavior of microstructure evolution of aluminum alloy 7050 under the condition of different forging process parameters by means of combining materials physical model with finite element code. For the purpose of establishing constitutive equation and physical model of microstructure evolution, the isothermal compression test were performed by machine Gleeble 1500 on the condition of temperatures ranging from 250 deg. C to 450 deg. C and constant strain rates of 0.01s-1, 0.1s-1, 1s-1 and 10s-1. The behaviors of microstructure evolutions of aluminum alloy 7050 under difference process parameters were studied by metallographic observations. The experiment results showed that recrystallization during forming process occurred at the critical strain and the volume fraction of recrystallization changed with the temperature and strain rate. According to the results of isothermal compression test, a constitutive equation and an empirical model of DRX were obtained. A finite element code DEFORM 3D was used to analyze the influence of different forging process parameters on the behavior of microstructure evolution in details. The present model and simulation method can be served as a useful tool to predict and control the properties and shape of aluminum alloy 7050 components during forging.

Yi Youping; Shi Yan; Yang Jihui; Lin Yongcheng [School of Mechanical and Electrical Engineering, Central South University, 410083 Changsha (China)

2007-04-07

3

Effects of Forging Process Parameters on Microstructure Evolution of Aluminum Alloy 7050  

NASA Astrophysics Data System (ADS)

The objective of this work is to investigate the behavior of microstructure evolution of aluminum alloy 7050 under the condition of different forging process parameters by means of combining materials physical model with finite element code. For the purpose of establishing constitutive equation and physical model of microstructure evolution, the isothermal compression test were performed by machine Gleeble 1500 on the condition of temperatures ranging from 250°C to 450°C and constant strain rates of 0.01s-1, 0.1s-1, 1s-1 and 10s-1. The behaviors of microstructure evolutions of aluminum alloy 7050 under difference process parameters were studied by metallographic observations. The experiment results showed that recrystallization during forming process occurred at the critical strain and the volume fraction of recrystallization changed with the temperature and strain rate. According to the results of isothermal compression test, a constitutive equation and an empirical model of DRX were obtained. A finite element code DEFORM 3D was used to analyze the influence of different forging process parameters on the behavior of microstructure evolution in details. The present model and simulation method can be served as a useful tool to predict and control the properties and shape of aluminum alloy 7050 components during forging.

Yi, Youping; Shi, Yan; Yang, Jihui; Lin, Yongcheng

2007-04-01

4

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

5

Deformation processes in forging ceramics  

NASA Technical Reports Server (NTRS)

The deformation processes involved in the forging of refractory ceramic oxides were investigated. A combination of mechanical testing and forging was utilized to investigate both the flow and fracture processes involved. Deformation studies of very fine grain Al203 revealed an apparent transition in behavior, characterized by a shift in the strain rate sensitivity from 0.5 at low stresses to near unity at higher stresses. The behavior is indicative of a shift in control between two dependent mechanisms, one of which is indicated to be cation limited diffusional creep with significant boundary enhancement. The possible contributions of slip, indicated by crystallographic texture, interface control of the diffusional creep and inhomogeneous boundary sliding are also discussed. Additional experiments indicated an independence of deformation behavior on MgO doping and retained hot pressing impurities, at least for ultrafine grained material, and also an independence of test atmosphere.

Cannon, R. M.; Rhodes, W. H.

1973-01-01

6

1 INTRODUCTION The cold forging processes, including extrusion,  

E-print Network

1 INTRODUCTION The cold forging processes, including extrusion, drawing, upsetting, and heading has a large effect on the cold forging, because it not only changes the forming force but also methods were invented to evaluate the friction condition during cold forging, such as ring compression

Paris-Sud XI, Université de

7

Cold forging process design based on the induction of analytical knowledge  

Microsoft Academic Search

In this paper, a cold forging process design method based on the induction of analytical knowledge is proposed. The analysis engine, which is a finite-element-based program, is used to analyze various multi-stage cold forging processes based on pre-defined process condition parameters and tooling geometry. According to the simulation results, a knowledge-acquisition procedure is instituted, i.e. a neural network model is

Quang-Cherng Hsu; Rong-Shean Lee

1997-01-01

8

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

9

Applying case-based reasoning to cold forging process planning  

Microsoft Academic Search

On the basis of the practical situation of cold forging process planning, the disadvantages of a rule-based solution are discussed, and a case-based reasoning-based cold forging process planning (CFPP) system model is proposed. Several key problems involved are analyzed, among which a feature-based part representation scheme and a two-level retrieval mechanism are introduced to solve the problems of case representation

Yonggang Lei; Yinghong Peng; Xueyu Ruan

2001-01-01

10

Processing and structure of high-energy-rate-forged 21-6-9 and 304L forgings  

SciTech Connect

Two 304L and three Nitronic 40 (21-6-9) high energy rate processed forgings were studied to determine interrelationships that exist between forging history, mechanical properties, microstructure, macrostructure, and substructure. A striking observation is the wide variation in properties and structure between different forgings and also between different locations within an individual forging. Variations were related to either finishing temperature of the last forming stage or to the forming sequence. For example, lower finishing temperatures resulted in higher dislocation densities and therefore higher strengths. Higher finishing temperatures promoted dynamic recrystallization, lower dislocation densities, and lower strengths. With respect to forming sequence, locations in the forging which are formed first undergo a number of additional thermal cycles while the rest of the part is being formed. These areas are usually recrystallized and have lower dislocation densities, and therefore lower strengths relative to locations formed later in the sequence.

Mataya, M.C.; Carr, M.J.; Krenzer, R.W.; Krauss, G.

1981-08-10

11

Processing and structure of high-energy-rate-forged 21-6-9 and 304L forgings  

SciTech Connect

Two 304L and three Nitronic 40 (21-6-9) high energy rate processed forgings were studied to determine interrelationships that exist between forging history, mechanical properties, microstructure, macrostructure, and substructure. A striking observation is the wide variation in properties and structure between different forgings and also between different locations within an individual forging. Variations were related to either finishing temperature of the last forming stage or to the forming sequence. For example, lower finishing temperatures resulted in higher dislocation densities and therefore higher strengths. Higher finishing temperatures promoted dynamic recrystallization, lower dislocation densities, and lower strengths. With respect to forming sequence, locations in the forging which are formed first undergo a number of additional thermal cycles while the rest of the part is being formed. These areas are usually recrystallized and have lower dislocation densities.

Mataya, M.C.; Carr, M.J.; Krenzer, R.W.; Krauss, G.

1981-08-10

12

New surface processes for cold forging of steels  

Microsoft Academic Search

The authors present a new generation of surface processings for cold forging of steels. These coatings, designed to replace phosphatation, are easy to implement and less polluting. A drawing–seizure test procedure is also proposed to evaluate the tribological performances of these new coatings more objectively and to compare them to standard zinc phosphatation. Test results, including the occurrence of boundary

L Dubar; J. P Bricout; C Wierre; P Meignan

1998-01-01

13

Numerical Simulation and Optimization of the Forging Process Jean-Loup Chenot1  

E-print Network

hal-00677694,version1-9Mar2012 Author manuscript, published in "International Cold Forging CongressNumerical Simulation and Optimization of the Forging Process Jean-Loup Chenot1 , Pierre the effectiveness of the procedure with the FORGE3 computer code. The optimization criterion can be on the forming

Paris-Sud XI, Université de

14

Geometry-oriented knowledge-based system for preliminary process design of cold-forged parts  

Microsoft Academic Search

This paper presents an integrated architecture of a geometry-oriented knowledge-based process-design system (GEOPDE) for multistage\\u000a cold forging of solid and hollow parts. It deals with the unit processes of upsetting, forward extrusion, backward extrusion\\u000a and with combinations of these processes. By using the notion of group technology, the forging processes and forging part\\u000a geometries are classified. With Prolog as the

Q. C. Hsu; R. S. Lee

1991-01-01

15

Construction of PC-based expert system for cold forging process design  

Microsoft Academic Search

Cold forging process design is a field where the theory has not been established until present, and it depends on skilled designers with long time experience and intuition. Consequently, it is difficult for designers with shallow experience to cope, since process design needs time and cost. Thus, computer-based expert system for cold forging process design targeted to beginners has been

Tsutao Katayama; Masami Akamatsu; Yoji Tanaka

2004-01-01

16

Automate and accelerate build and release processes IBM Rational Build Forge  

E-print Network

n n n n n n n Automate and accelerate build and release processes IBM Rational Build Forge-wide builds throughout the software delivery lifecycle IBM Rational® Build Forge® soft- ware automates complex build and release processes to take software and systems development to new levels of automation

17

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

18

An Intelligent Computation Approach to Process Planning in Multiple-Step Cold Forging  

Microsoft Academic Search

An intelligent computation approach to time and cost reduction in process planning of cold forging operations is illustrated. The problem taken into consideration is the generation of optimized working sequences in the fabrication of multi-diameter shafts through multiple-step cold forging. A supervised learning neural network paradigm was employed in order to identify the technologically feasible working sequences to be considered

R. Teti; A. Langella; D. D'Addona

1999-01-01

19

Proposal to study stem forgings  

SciTech Connect

Reservoir designs consist of two primary features including the stem(s) and the body segment. The stem is either an integral part of the reservoir or is joined at some point in the fabrication sequence. The current interest is in high strength stems for advanced reservoir designs. The processing necessary to achieve these strength levels may result in heavily cold worked microstructures which may not interface well with the stem requirements. For instance, cold worked 316 plate stock has shown decreased hydrogen compatibility when contrasted to the annealed version in laboratory tests. More recently, Precision Forge produced a 100 ksi yield strength, 304L stem forging with a heavily deformed microstructure which also may show decreased compatibility in hydrogen. The proposed forging contract will evaluate the influence of forging parameters on the microstructure and mechanical properties of 304L and 316 stem forgings. A summary of the data available on 304L stem forgings is shown graphically. The yield strength values are shown for each set of forging parameters. Tensile tests and microstructural examination will be conducted to complete the information for 304L and create a similar graph for 316 stem forgings.

Odegard, B.C.

1982-06-25

20

An expert system for cold forging process design based on a depth-first search  

Microsoft Academic Search

Due to the non-deterministic nature of process sequence design for multi-stage cold forging, various process designs are available depending on the initial billet geometry and the order of basic processes such as forward\\/backward extrusion, upsetting and trimming process. Therefore, various process sequences should be determined and compared to obtain an optimal solution. For this purpose, a depth-first search, a searching

Hong-Seok Kim; Yong-Taek Im

1999-01-01

21

Expert system for multi-stage cold-forging process design with a re-designing algorithm  

Microsoft Academic Search

Cold forging has recently become one of the competitive technologies in manufacturing. In order to improve the productivity of cold forging at low production cost, an integrated systems approach is necessary in handling the material preparation and the optimum process design considering the forming machines, tooling, and operation, including quality control. As the first step toward this approach, an expert

Hong-Seok Kim; Yong-Taek Im

1995-01-01

22

Numerical modeling of axi-symmetrical cold forging process by ``Pseudo Inverse Approach''  

NASA Astrophysics Data System (ADS)

The incremental approach is widely used for the forging process modeling, it gives good strain and stress estimation, but it is time consuming. A fast Inverse Approach (IA) has been developed for the axi-symmetric cold forging modeling [1-2]. This approach exploits maximum the knowledge of the final part's shape and the assumptions of proportional loading and simplified tool actions make the IA simulation very fast. The IA is proved very useful for the tool design and optimization because of its rapidity and good strain estimation. However, the assumptions mentioned above cannot provide good stress estimation because of neglecting the loading history. A new approach called "Pseudo Inverse Approach" (PIA) was proposed by Batoz, Guo et al.. [3] for the sheet forming modeling, which keeps the IA's advantages but gives good stress estimation by taking into consideration the loading history. Our aim is to adapt the PIA for the cold forging modeling in this paper. The main developments in PIA are resumed as follows: A few intermediate configurations are generated for the given tools' positions to consider the deformation history; the strain increment is calculated by the inverse method between the previous and actual configurations. An incremental algorithm of the plastic integration is used in PIA instead of the total constitutive law used in the IA. An example is used to show the effectiveness and limitations of the PIA for the cold forging process modeling.

Halouani, A.; Li, Y. M.; Abbes, B.; Guo, Y. Q.

2011-05-01

23

Process design of the cold forging of a billet by forward and backward extrusion  

Microsoft Academic Search

The process design of a forward and backward extruded axi-symmetric part has been studied. The important factors in the cold forging of an intricate part are the shape of the initial billet, possibility produced as a single-stage operation, as well as the shape of the pre-form. On the basis of theoretical knowledge on process design, numerical simulation of the cold

Hae Yong Cho; Gyu Sik Min; Chang Yong Jo; Myung Han Kim

2003-01-01

24

An investigation of a new near-beta forging process for titanium alloys and its application in aviation components  

Microsoft Academic Search

In this paper, the authors present a new near-beta forging process, in which materials are heated at about 15°C below the beta transus, to improve the combined properties of titanium alloys. Materials processed by the near-beta forging process, followed by rapid water-cooling, then high temperature toughening and low temperature strengthening heat treatments, produce a new kind of microstructure for titanium

Y. G. Zhou; W. D. Zeng; H. Q. Yu

2005-01-01

25

Manufacturing of Precision Forgings by Radial Forging  

SciTech Connect

Radial forging is a multi purpose incremental forging process using four tools on the same plane. It is widely used for the forming of tool steels, super alloys as well as titanium- and refractory metals. The range of application goes from reducing the diameters of shafts, tubes, stepped shafts and axels, as well as for creating internal profiles for tubes in Near-Net-Shape and Net-Shape quality. Based on actual development of a weight optimized transmission input shaft, the specific features of radial forging technology is demonstrated. Also a Finite Element Model for the simulation of the process is shown which leads to reduced pre-processing effort and reduced computing time compared to other published simulation methods for radial forging. The finite element model can be applied to quantify the effects of different forging strategies.

Wallner, S.; Harrer, O.; Buchmayr, B. [Chair of Metal Forming, Department Product Engineering, University of Leoben, Franz Josef Strasse 18, 8700 Leoben (Austria); Hofer, F. [GFM GmbH, Ennser Strasse 14, 4403 Steyr (Austria)

2011-01-17

26

Fabrication and densification enhancement of SiC-particulate-reinforced copper matrix composites prepared via the sinter-forging process  

NASA Astrophysics Data System (ADS)

The fabrication of copper (Cu) and copper matrix silicon carbide (Cu/SiCp) particulate composites via the sinter-forging process was investigated. Sintering and sinter-forging processes were performed under an inert Ar atmosphere. The influence of sinter-forging time, temperature, and compressive stress on the relative density and hardness of the prepared samples was systematically investigated and subsequently compared with that of the samples prepared by the conventional sintering process. The relative density and hardness of the composites were enhanced when they were prepared by the sinter-forging process. The relative density values of all Cu/SiCp composite samples were observed to decrease with the increase in SiC content.

Shabani, Mohammadmehdi; Paydar, Mohammad Hossein; Moshksar, Mohammad Mohsen

2014-09-01

27

A simplified pseudo inverse approach for damage modeling in the cold forging process  

NASA Astrophysics Data System (ADS)

This paper presents a simplified numerical method called "Pseudo Inverse Approach" (PIA) for damage prediction in metal forging process modeling and optimization. The approach is based on the knowledge of the final part shape. Some intermediate configurations are introduced and corrected by using a free surface method to consider the deformation paths. Based on the equivalent stress notion and tensile curve, a robust direct algorithm of plasticity is formulated and implemented. The plasticity is coupled with the ductile damage by using a strain based ductile damage model. The forging results obtained by the PIA are compared to those obtained by an incremental approach to show the efficiency and accuracy of the PIA, as well as the abilities to make the damage prediction.

Halouani, A.; Li, Y. M.; Abbès, B.; Guo, Y. Q.

2013-05-01

28

A Simplified Inverse Approach for the Simulation of Axi-Symmetrical Cold Forging Process  

NASA Astrophysics Data System (ADS)

This paper presents the formulation of an axi-symmetric element based on an efficient method called "Inverse Approach" (I.A.) for the numerical modeling of cold forging process. In contrast to the classical incremental methods, the Inverse Approach exploits the known shape of the final part and executes the calculation from the final part to the initial billet. The assumptions of the proportional loading and the simplified tool actions make the I.A. calculation very fast. The metal's incompressibility is ensured by the penalty method. The comparison with ABAQUS® and FORGE® shows the efficiency and limitations of the I.A. This simplified method will be a good tool for the preliminary preform design.

Halouani, A.; Li, Y. M.; Abbès, B.; Guo, Y. Q.

2011-01-01

29

Processing-structure relationship in open die hot forged W-Hf-Ti  

SciTech Connect

The processing-structure relationship in a series of presintered W-Hf-Ti alloys open die hot forged at 1,300--1,350 C has been examined. The alloys were prepared with W levels varying from 60--95 wt% while keeping the Hf/Ti ratio constant at 1:3. The alloys were fabricated from elemental powders by mechanical mixing, cold isostatic pressing and sintering at 1,500 C before open die hot forging. Other alloy compositions within this W range were also produced to determine if altering the Hf and Ti ratio to 1:2 and 1:1 had any effect on the microstructures produced after hot forging. Microstructural observations using optical microscopy and scanning electron microscopy revealed that the structures were composed of a complex mixture of 3 microconstituents in the high-W containing alloys. W grains were typically surrounded by a thin layer composed of a less W-rich phase containing some Ti. It appeared as if this less W-rich layer (in several of the compositions) isolated the W particles from each other. Interspersed among these W-rich phases was a Ti-rich phase which contained a very fine dispersion of W-rich particles. X-ray diffraction experiments confirmed that a W solid solution and a Ti solid solution were present in each alloy. In addition, W{sub 2}Hf was detected in the alloys that had a Hf/Ti ratio of 1:2 and 1:1.

Pletka, B.J.; Subhash, G.; Edelman, D. [Michigan Technological Univ., Houghton, MI (United States); Dowding, R.J. [Army Research Lab., Aberdeen Proving Grounds, MD (United States)

1996-06-01

30

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.

31

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

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

A study on the automated process planning system for cold forging of non-axisymmetric parts using FVM simulation  

Microsoft Academic Search

A process planning system for cold forging of non-axisymmetric parts of comparatively simple shape was developed in this study. Programs for the system have been written with Visual LISP in AutoCAD. When a product is drawn on AutoCAD, it needs that the shape of the product is drawn with the solid line and the hidden line, and with the plane

B. K Lee; H. H Kwon; H. Y Cho

2002-01-01

34

Effect of precipitates on microstructures and properties of forged Mg–10Gd–2Y–0.5Zn–0.3Zr alloy during ageing process  

Microsoft Academic Search

The precipitate behavior during forging and ageing process of Mg–10Gd–2Y–0.5Zn–0.3Zr alloy has been investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The mechanical properties of the alloy after forging and ageing process have been evaluated using Vickers hardness and room-temperature tensile tests. The results show that precipitation of 14H-type long period stacking order (LPSO) phase is the

X. Z. Han; W. C. Xu; D. B. Shan

2011-01-01

35

FE simulation as a must tool in cold\\/warm forging process and tool design  

Microsoft Academic Search

This paper describes the brief history and the current status of practical use of FE simulations with examples. Key points for practical use of FE simulation as a daily work tool in forging area is also discussed followed by future approaches for more effective use of the FE simulation.

Hyunkee Kim; Tetsuji Yagi; Masahito Yamanaka

2000-01-01

36

Research on orbital cold forging for the edge cam of automobile fuel injection pump  

NASA Astrophysics Data System (ADS)

The experimental investigation and theoretical analysis of an orbital cold forging of an edge cam was explored. The effects of blank shape and the process parameters on the edge cam forming are discussed. Photoplastic technology was successfully applied to the simulation of an orbital cold forging process applied to an edge cam. The China-made polycarbonate (PCBA) was used as a simulation material, and a 3-D strain distribution was obtained inside the model materials, which provided theoretical guidance for optimizing process parameters on the orbital cold forging of the edge cam. The factors that caused a crack were identified and the deformation laws in orbital cold forging of an edge cam were clarified. The metal flow line, hardness, microstructures and accuracy of the orbital cold forged edge cam were found to meet the required service properties of the product.

Chi, Zhang; Bo, Xu

2005-12-01

37

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

38

Process Modeling In Cold Forging Considering The Process-Tool-Machine Interactions  

NASA Astrophysics Data System (ADS)

In this paper, a methodic approach is presented for the determination and modeling of the axial deflection characteristic for the whole system of stroke-controlled press and tooling system. This is realized by a combination of experiment and FE simulation. The press characteristic is uniquely measured in experiment. The tooling system characteristic is determined in FE simulation to avoid experimental investigations on various tooling systems. The stiffnesses of press and tooling system are combined to a substitute stiffness that is integrated into the FE process simulation as a spring element. Non-linear initial effects of the press are modeled with a constant shift factor. The approach was applied to a full forward extrusion process on a press with C-frame. A comparison between experiments and results of the integrated FE simulation model showed a high accuracy of the FE model. The simulation model with integrated deflection characteristic represents the entire process behavior and can be used for the calculation of a mathematical process model based on variant simulations and response surfaces. In a subsequent optimization step, an adjusted process and tool design can be determined, that compensates the influence of the deflections on the workpiece dimensions leading to high workpiece accuracy. Using knowledge on the process behavior, the required number of variant simulations was reduced.

Kroiss, Thomas; Engel, Ulf; Merklein, Marion

2010-06-01

39

Saugus Iron Works Forge  

USGS Multimedia Gallery

The Saugus Iron Works forge, which used a large hammer to compress the iron. Forging strenghened the iron, which, right out of the blast furnace, was brittle. The Saugus River, which powered the forge, can be seen in the background....

40

The effects of processing bath parameters on the quality and performance of zinc phosphate stearate coatings  

Microsoft Academic Search

In cold metal-forging processes, low-friction coatings often provide the main part of the lubrication. In many cases, zinc phosphate stearate (ZPS) coatings are used. Many parameters affect the coatings' quality and performance. In this paper the typical Brinell indentation test is used to answer two industrial requirements: first, to reveal the sensitivity of the coating with regard to the ageing

L Lazzarotto; C Maréchal; L Dubar; A Dubois; J Oudin

1999-01-01

41

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

42

Injection forging: engineering and research  

Microsoft Academic Search

Injection forging is a nett-shape manufacturing process which enables the forming of complex component-forms that are difficult to form by conventional metal-conversion processes. The state-of-the-art of the research in this subject is reviewed with reference to different process configurations, forming limits, energy\\/pressure requirements, process modelling and product forms.

Raj Balendra; Yi Qin

2004-01-01

43

Influence of Process Parameters on the Mechanical Behavior of an Ultrafine-Grained Al Alloy  

NASA Astrophysics Data System (ADS)

Aluminum alloys with nanocrystalline (NC) and ultrafine grain (UFG) size are of interest because of their strengths that are typically 30 pct greater than conventionally processed alloys of the same composition. In this study, UFG AA 5083 plate was prepared by quasi-isostatic (QI) forging of cryomilled powder, and the microstructure and mechanical behavior was investigated and compared with the behavior of coarse-grained AA 5083. Forging parameters were adjusted in an effort to strengthen the UFG material while retaining some tensile ductility. Different forging parameters were employed on three plates, with approximate dimensions of 254 mm diameter and 19 mm thickness. The overarching goal of the current effort was to increase strength through minimized grain growth during processing while maintaining ductility by breaking up prior particle boundaries (PPBs) with high forging pressures. Mechanical tests revealed that strength increased inversely with grain size, whereas ductility for some of the experimental materials was preserved at the level of the conventional alloy. The application of the Hall-Petch relationship to the materials was studied and is discussed in detail with consideration given to strengthening mechanisms other than grain size, including dispersion (Orowan), solid solution, and dislocation strengthening.

Topping, Troy D.; Ahn, Byungmin; Li, Ying; Nutt, Steven R.; Lavernia, Enrique J.

2012-02-01

44

Forged-on wellheads prove reliable  

SciTech Connect

Forged-on wellheads require approximately 1 hour installation compared to 3 to 5 hours for a conventional slip-on and weld wellhead. A cold forging process eliminates the need for welding the casinghead to the initial casing string. Discussed here are field installation, advantages and disadvantages from the operator's viewpoint, and some of the tool improvements made since the field tests.

Howard, J.A. (Tenneco Oil Co., Lafayette, La. (US))

1989-01-01

45

Effect of Various Heat Treatment Processes on Fatigue Behavior of Tool Steel for Cold Forging Die  

NASA Astrophysics Data System (ADS)

Effects of various heat treatment processes, including "Q/T (quenching and tempering)", "Q/CT/T (Quenching, cryogenic treatment and tempering)", "Q/T (quenching and tempering) + Ti-nitriding" and "Q/CT/T (Cryogenic treatment and tempering) + Ti-nitriding", on S-N fatigue behavior of AISI D2 tool steel were investigated. The optical micrographs and Vicker's hardness values at near surface and core area were examined for each specimen. Uniaxial fatigue tests were performed by using an electro-magnetic resonance fatigue testing machine at a frequency of 80 Hz and an R ratio of -1. The overall resistance to fatigue tends to decrease significantly with Ti-nitriding treatment compared to those for the general Q/T and Q/CT/T specimens. The reduced resistance to fatigue with Ti-nitriding is discussed based on the microstructural and fractographic analyses.

Jin, S. U.; Kim, S. S.; Lee, Y. S.; Kwon, Y. N.; Lee, J. H.

46

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

E-print Network

Page Fig. 1 - Typical wellhead assembly. Fig. 2 ? Ini'luence of forging reduction ratio upon 16 longitudinal (RAL) and transverse (RAT) reduction in area values. Fig. 3 ? Effect of notch root radius upon the apparent fracture toughness of two...-integral vs. crack length for a 126 specimen with R-L orientation from the 23 cm diameter barstock. xiv Page Fig. 53 - Schematic of flaw configuration in simple 147 leak-before-break analysis. INTRODUCTION A typical wellhead assembly for production...

Desadier, Christopher Earl

2012-06-07

47

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

48

Controlled Forging of a Nb Containing Microalloyed Steel for Automotive Applications  

NASA Astrophysics Data System (ADS)

Controlled forging of microalloyed steels is a viable economical process for the manufacture of automotive parts. Ferrite grain refinement and precipitation hardening are the major microstructural parameters to enhance the mechanical properties of the forged components. In the current study, a modified thermomechanical treatment for additional ferrite grain refinement is developed by exploiting the effect of Nb in increasing the T NR (no recrystallization temperature) and via phase transformation from a pancaked austenite. This is accomplished by performing the final passes of forging below the T NR temperature followed by a controlled cooling stage to produce a mixture of fine grained ferrite, small scaled acicular ferrite as well as a limited amount of martensite. The effect of processing parameters in terms of forging strain, cooling rate and aging condition on the microstructure and mechanical properties of a medium carbon, Nb containing microalloyed steel is investigated. An attempt is made to identify a suitable microstructure that provides a proper combination of high strength and good impact toughness. The processing-microstructure relationships for the proposed novel forging procedure are discussed, and directions for further improvements are outlined.

Nakhaie, Davood; Hosseini Benhangi, Pooya; Fazeli, Fateh; Mazinani, Mohammad; Zohourvahid Karimi, Ebrahim; Ghandehari Ferdowsi, Mahmoud Reza

2012-12-01

49

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

50

Static and Dynamic Modelling of Materials Forging Coryn A.L. Bailer-Jones, David J.C. MacKay  

E-print Network

reliably predict the microstructures of forged materials. We analyse two types of forging, cold forging. For the cold forging problem we employ the Gaussian process model. This probabilistic model can be seenStatic and Dynamic Modelling of Materials Forging Coryn A.L. Bailer-Jones, David J.C. Mac

Bailer-Jones, Coryn

51

A finite element analysis of cold-forging dies using two- and three-dimensional models  

Microsoft Academic Search

The cold-forging process analysed in this paper deals with the production of a hexagonal shape on the head of a bolt. The process utilises a die known as a “Standard Trim Die” which is forced at velocity onto the workpiece to form the bolt head. This process is a combination of cutting and forging. By definition, a cold-forging operation occurs

Conor McCormack; John Monaghan

2001-01-01

52

Precision design of roll-forging die and its application in the forming of automobile front axles  

Microsoft Academic Search

Roll-forging is an efficient way to produce long or thin metal parts, and the design of rolling die is a sophisticated problem duo to the complex relative motions of dies and forging piece. In the first part of this paper, the kinematic relation between the surface of rolling die and that of forging piece during the roll-forging process are analysed,

Zhong-Yi Cai

2005-01-01

53

31. FORGE, ANVIL, POWER FORGE HAMMER (FRONT TO BACK), AND ...  

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

31. FORGE, ANVIL, POWER FORGE HAMMER (FRONT TO BACK), AND DOORWAY INTO MAIN SHOP-LOOKING SOUTHWEST. - W. A. Young & Sons Foundry & Machine Shop, On Water Street along Monongahela River, Rices Landing, Greene County, PA

54

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

55

Model for radial forging of superalloys  

SciTech Connect

The goal of process modeling is to optimize existing processes, design new processes, and determine causes and/or corrective actions for specific manufacturing problems. Models for most of Allvac`s processes have now been developed, using a combination of in-house proprietary computer codes and commercially available software. This article describes how process modeling has been successfully applied at Allvac in the key process of radial forging.

Minisandram, R.S. [Teledyne Allvac, Monroe, NC (United States)

1995-10-01

56

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

57

Cold Forging Die Design: Recent Advanced and Future Trends  

NASA Astrophysics Data System (ADS)

Die design in the forging process become crucial as the production cost and accuracy of the forged part being tighten. The study present a review of the current advanced of die design used in forging process and the system associated with in order to enhance the design process and performance of the die. At the end of this study future challenges of the die design area and the approach taken to develop a support system that can fulfilled the customer demand is also outlined.

Abdullah, A. B.; Samad, Z.

58

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

59

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

60

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

61

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

62

Parameter adaptive estimation of random processes  

NASA Technical Reports Server (NTRS)

This paper is concerned with the parameter adaptive least squares estimation of random processes. The main result is a general representation theorem for the conditional expectation of a random variable on a product probability space. Using this theorem along with the general likelihood ratio expression, the least squares estimate of the process is found in terms of the parameter conditioned estimates. The stochastic differential for the a posteriori probability and the stochastic differential equation for the a posteriori density are found by using simple stochastic calculus on the representations obtained. The results are specialized to the case when the parameter has a discrete distribution. The results can be used to construct an implementable recursive estimator for certain types of nonlinear filtering problems. This is illustrated by some simple examples.

Caglayan, A. K.; Vanlandingham, H. F.

1975-01-01

63

Sensitivity analysis of submerged arc welding process parameters  

Microsoft Academic Search

Selection of process parameters has great influence on the quality of a welded connection. Mathematical modelling can be utilized in the optimization and control procedure of parameters. Rather than the well-known effects of main process parameters, this study focuses on the sensitivity analysis of parameters and fine tuning requirements of the parameters for optimum weld bead geometry. Changeable process parameters

Serdar Karao?lu; Abdullah Seçgin

2008-01-01

64

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

65

Expert system of cold forging defects using risk analysis tree network with fuzzy language  

Microsoft Academic Search

The authors have developed an expert system for detecting the risk of forging defects and their causes in cold processes. The system employs risk analysis for a computer-aided process planning system. In addition, the authors investigated topics that affect typical forging defects. Based on the investigation, the authors developed risk analysis tree networks to evaluate the risk potential and describe

T Ohashi; M Motomura

2000-01-01

66

29 CFR 1910.218 - Forging machines.  

Code of Federal Regulations, 2010 CFR

...in Table O-11. (2) Hydraulic forging presses. When dies are being changed...to hot trimming presses. (2) Cold trimming presses. Cold trimming...flywheel shall be at rest. (i) Other forging equipment —(1)...

2010-07-01

67

29 CFR 1910.218 - Forging machines.  

Code of Federal Regulations, 2012 CFR

...in Table O-11. (2) Hydraulic forging presses. When dies are being changed...to hot trimming presses. (2) Cold trimming presses. Cold trimming...flywheel shall be at rest. (i) Other forging equipment —(1)...

2012-07-01

68

29 CFR 1910.218 - Forging machines.  

Code of Federal Regulations, 2013 CFR

...in Table O-11. (2) Hydraulic forging presses. When dies are being changed...to hot trimming presses. (2) Cold trimming presses. Cold trimming...flywheel shall be at rest. (i) Other forging equipment —(1)...

2013-07-01

69

29 CFR 1910.218 - Forging machines.  

...in Table O-11. (2) Hydraulic forging presses. When dies are being changed...to hot trimming presses. (2) Cold trimming presses. Cold trimming...flywheel shall be at rest. (i) Other forging equipment —(1)...

2014-07-01

70

29 CFR 1910.218 - Forging machines.  

Code of Federal Regulations, 2011 CFR

...in Table O-11. (2) Hydraulic forging presses. When dies are being changed...to hot trimming presses. (2) Cold trimming presses. Cold trimming...flywheel shall be at rest. (i) Other forging equipment —(1)...

2011-07-01

71

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

72

Department of Industrial Engineering Spring 2012 Lyophilization Process Parameter Study  

E-print Network

PENNSTATE Department of Industrial Engineering Spring 2012 Lyophilization Process Parameter Study of human life. They developed a lyophilization process to freeze-dry products for shipping at ambient temperatures. Throughout this parameter study, Team Life Support analyzed the lyophilization process

Demirel, Melik C.

73

Saugus Iron Works Forge and Mill  

USGS Multimedia Gallery

A view of the forge at Saugus Iron Works, as well as the rolling and slitting mill. The forge used a large hammer to compress the iron. Forging strenghened the iron, which, right out of the blast furnace, was brittle. The rolling and slitting mill would make bars of iron that could be cut into thing...

74

A Knowledge base model for complex forging die machining Bernardin Mawussi a,b  

E-print Network

the complexity and the finishing requirements of die shapes in order to limit machining operation (Doege1 A Knowledge base model for complex forging die machining Bernardin Mawussi a,b , Laurent Tapie a die. These evolutions, combined with High Speed Machining (HSM) process of forging die lead

Paris-Sud XI, Université de

75

Simulation of cold forging under consideration of residual stresses induced by preceding drawing  

NASA Astrophysics Data System (ADS)

Preforming steps may have a significant influence on the subsequent metal flow and damage behaviour in cold forging. Also the residual stress in the final part may be influenced by preforming operations. But, in numerical analyses of cold forging processes the preforming operations e.g. preceding drawing are most of the time neglected. Based on an exemplary cold forging process the present study shows the influence of a prior drawing process on the behavior of subsequent forging. For this purpose an elastic-plastic calculation is done using the commercial software Deform™. It is shown that considering a preceding drawing process has a significant influence on the computed material flow, damage behavior and die load during forging. Examination of the residual stress distribution after forging shows crucial deviations between the results obtained with or without preceding drawing. Further simulation studies show that after drawing there is also an influence of the forging direction related to the drawing direction on the simulation results. To verify the results obtained from the computations, forging trials are performed using primary material manufactured in a drawing operation.

Hatzenbichler, Thomas; Buchmayr, Bruno; Walzl, Alexander

2011-01-01

76

Failure analysis of cold forging dies using FEA  

Microsoft Academic Search

The results presented within this paper represent part of a larger collaborated investigation being conducted by Trinity College, Dublin and an industrial partner. The particular cold forging process analysed was the method used to ‘trim’ a hexagonal shape on the head of a fastener. The fastener head geometry is achieved by forcing the die, known as a trim die because

Conor MacCormack; John Monaghan

2001-01-01

77

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

78

The development and production of thermo-mechanically forged tool steel spur gears  

NASA Technical Reports Server (NTRS)

A development program to establish the feasibility and applicability of high energy rate forging procedures to tool steel spur gears was performed. Included in the study were relatively standard forging procedures as well as a thermo-mechanical process termed ausforming. The subject gear configuration utilized was essentially a standard spur gear having 28 teeth, a pitch diameter of 3.5 inches and a diametral pitch of 8. Initially it had been planned to use a high contact ratio gear design, however, a comprehensive evaluation indicated that severe forging problems would be encountered as a result of the extremely small teeth required by this type of design. The forging studies were successful in achieving gear blanks having integrally formed teeth using both standard and thermo-mechanical forging procedures.

Bamberger, E. N.

1973-01-01

79

Thermo-mechanical modeling of the electrically-assisted manufacturing (EAM) technique during open die forging  

NASA Astrophysics Data System (ADS)

This thesis contains all of the steps which allow the Electrically-Assisted Manufacturing (EAM) technique to be experimentally explored and analytically modeled for an electrically-assisted forging operation. Chapter 1 includes the problem statement, proposed solution, and literature reviews on EAM. Chapter 2 describes a thorough background on the EAM technique, highlights prior EAM research, and explains the research approach taken for this thesis. The coupled thermo-mechanical modeling strategy, along with the introduction of the Electroplastic Effect Coefficient (EEC) is provided in Chapter 3. Chapter 4 explains the two different approaches to determine the EEC profiles when modeling a particular metal. The simplified EAF mechanical model for electrically-assisted forging is presented in Chapter 5. Also in this chapter, the same modeling methodology (i.e. thermo-mechanical, EEC, etc.) is used to predict loads for an electrically-assisted bending (EAB) process. The following chapters explore how different material- and process-based parameters affect the EAF technique. Chapter 6 examines how different workpiece contact areas affect EAF effectiveness, along with an exploration of how well different metal forming lubricants perform with EAF. Chapter 7 explores if there is a difference in the thermal or mechanical profiles of specimens undergoing EAF forging tests with different average grain sizes. Chapter 8 examines the same effects as the previous chapter on specimens with varying levels of prior cold work. The materials- and process-based simplifications and sensitivities of the proposed modeling strategy are outlined in Chapter 9. Chapters 10-14 include the science behind the electroplastic effect, conclusions, future work, broader impacts, and intellectual merit, respectively. The overall intention of this thesis is to show the candidate's ability to take an idea for a new manufacturing process, prove that it works, and then understand and model the process such that it may be competitive within relevant industries.

Salandro, Wesley A.

80

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

81

Laser-dispersing of forging tools using AlN-ceramics  

NASA Astrophysics Data System (ADS)

Forging tools for aluminum work pieces show an increased adhesive wear due to cold welding during the forging process. Laser dispersing offers at this point a great potential to fabricate protective layers or tracks with tailored properties that reduce abrasive or adhesive wear at the surface of highly stressed components. Using different process strategies, four metal ceramic compounds applied on two substrate geometries were investigated regarding their structural and mechanical properties and their performance level. The subsequent forging tests have pointed out a positive effect and less adhesive residuals on the laser dispersed tool surface.

Noelke, C.; Luecke, M.; Kaierle, S.; Wesling, V.; Overmeyer, L.

2014-02-01

82

Assessment of NASA Dual Microstructure Heat Treatment Method for Multiple Forging Batch Heat Treatment  

NASA Technical Reports Server (NTRS)

NASA dual microstructure heat treatment technology previously demonstrated on single forging heat treat batches of a generic disk shape was successfully demonstrated on a multiple disk batch of a production shape component. A group of four Rolls-Royce Corporation 3rd Stage AE2100 forgings produced from alloy ME209 were successfully dual microstructure heat treated as a single heat treat batch. The forgings responded uniformly as evidenced by part-to-part consistent thermocouple recordings and resultant macrostructures, and from ultrasonic examination. Multiple disk DMHT processing offers a low cost alternative to other published dual microstructure processing techniques.

Gayda, John (Technical Monitor); Lemsky, Joe

2004-01-01

83

Analysis of the elastic characteristics at forging die for the cold forged dimensional accuracy  

Microsoft Academic Search

Systematic understanding of dimensional difference between forging tools and forged components is tried by both experimental and FEM analysis. The difference is mainly influenced by the elastic deflections of the die and the elastic recovery of the forged part. Since the die is continuously deformed during the loading, unloading, and ejecting stage, the elastic strains of die are measured at

Youngseon Lee; Junghwan Lee; T Ishikawa

2002-01-01

84

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

85

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

86

Sensitivity of cloud condensation nuclei activation processes to kinetic parameters  

E-print Network

Sensitivity of cloud condensation nuclei activation processes to kinetic parameters P. Y. Chuang1 circumstances. Here the sensitivity of particle activation to parameters that are related to kinetic processes adiabatic parcel models. We conclude that activation is not very sensitive to the thermal accommodation

Chuang, Patrick Y.

87

Parameter estimation for suspended sediment transport processes under random waves  

Microsoft Academic Search

This paper presents a parameter estimation method for suspended sediment transport processes subject to random wave environments. An objective function was constructed based on measurements of suspended sediment concentration profiles and the governing equation of sediment transport. The Chebyshev least square method was employed to approximate the process parameters, i.e. vertical eddy diffusivity (?) and net vertical velocity (w). The

Onyx W. H. Wai; Yue Shan Xiong; Sean O'Neil; Keith W. Bedford

2001-01-01

88

Decomposition of forging die for high speed machining Laurent Tapie 1, 2, Bernardin Kwamivi Mawussi 1, 2  

E-print Network

. The introduction of close die forging process in order to limit re-machining operation (Fig. 1) increases and topology must be taken into account during these machining operations with a high leveled refinement-1- Decomposition of forging die for high speed machining Laurent Tapie 1, 2, Bernardin Kwamivi

Paris-Sud XI, Université de

89

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

90

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

91

Partially observable Markov decision processes with imprecise parameters  

Microsoft Academic Search

This study extends the framework of partially observable Markov decision processes (POMDPs) to allow their parameters, i.e., the probability values in the state transition functions and the observation functions, to be imprecisely specified. It is shown that this extension can reduce the computational costs associated with the solution of these problems. First, the new framework, POMDPs with imprecise parameters (POMDPIPs),

Hideaki Itoh; Kiyohiko Nakamura

2007-01-01

92

Influence of processing parameters on the quality of soycurd (tofu)  

Microsoft Academic Search

Tofu, a non-fermented soybean curd is a nutritious and digestible product with a high quality protein. Tofu making procedure\\u000a includes soaking of beans, grinding, filtering, boiling, coagulating and moulding. The flavour, quality and the texture of\\u000a tofu produced is significantly influenced by its processing parameters. Studies were carried out on the processing parameters\\u000a like solid content of milk, thermal treatment

C. R. Rekha; G. Vijayalakshmi

93

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

94

Optimisation of submerged arc welding process parameters in hardfacing  

Microsoft Academic Search

In this paper, a feedforward neural network is used to model submerged arc welding (SAW) processes in hardfacing. The relationships between process parameters (arc current, arc voltage, welding speed, electrode protrusion, and preheat temperature) and welding performance (deposition rate, hardness, and dilution) are established, based on the neural network. A simulated annealing (SA) optimisation algorithm with a performance index is

H. L. Tsai; Y. S. Tarng; C. M. Tseng

1996-01-01

95

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

96

Microstructure evolution in a 316L stainless steel subjected to multidirectional forging and unidirectional bar rolling  

NASA Astrophysics Data System (ADS)

The formation of ultrafine-grained structures was studied in a 316L stainless steel during severe plastic deformation. The steel samples were processed up to a total amount of strain of 4 at ambient temperature using two different methods, i.e., multidirectional forging and unidirectional bar rolling. The large strain developed upon cold working resulted mechanical twinning and partial martensitic transformation. The latter was readily developed during multidirectional forging. After straining to the total amount of strain of 4, the austenite fractions comprised approximately- 0.45 as well as 0.15 in the rolled and forged samples, respectively. Both the multidirectional forging and bar rolling led to extensive grain refinement. The uniform microstructures consisting of austenite and ferrite crystallites with the transverse size of 60 nm and 30 nm were evolved at a total amount of strain of 4 in the rolled and forged samples, respectively. The grain refinement by severe plastic deformation was accompanied by an increase for the microhardness to 5380 and 4970 MPa for the forged and rolled samples, respectively.

Odnobokova, M.; Kipelova, A.; Belyakov, A.; Kaibyshev, R.

2014-08-01

97

Inverse Problems and Parameter Identification in Image Processing  

Microsoft Academic Search

Many problems in imaging are actually inverse problems. One reason for this is that conditions and parameters of the physical\\u000a processes underlying the actual image acquisition are usually not known. Examples for this are the inhomogeneities of the\\u000a magnetic field in magnetic resonance imaging (MRI) leading to nonlinear deformations of the anatomic structures in the recorded\\u000a images, material parameters in

Jens F. Acker; Benjamin Berkels; Kristian Bredies; Mamadou S. Diallo; Marc Droske; Christoph S. Garbe; Matthias Holschneider; Jaroslav Hron; Claudia Kondermann; Michail Kulesh; Peter Maass; Nadine Olischläger; Heinz-Otto Peitgen; Tobias Preusser; Martin Rumpf; Karl Schaller; Frank Scherbaum; Stefan Turek

98

Optimization of process parameters in stereolithography using genetic algorithm  

NASA Astrophysics Data System (ADS)

Stereolithography is the most popular RP process in which intricate models are directly constructed from a CAD package by polymerizing a plastic monomer. The application range is still limited, because dimensional accuracy is still inferior to that of conventional machining process. The ultimate dimensional accuracy of a part built on a layer-by-layer basis depends on shrinkage which depend on many factors such as layer thickness, hatch spacing, hatch style, hatch over cure and fill cure depth. The influence of the above factors on shrinkage in X and Y directions fit to the nonlinear pattern. A particular combination of process variables that would result same shrinkage rate in both directions would enable to predict shrinkage allowance to be provided on a part and hence the CAD model could be constructed including shrinkage allowance. In this concern, the objective of the present work is set as determination of process parameters to have same shrinkage rate in both X and Y directions. A genetic algorithm (GA) is proposed to find optimal process parameters for the above objective. This approach is an analytical approach with experimental sample data and has great potential to predict process parameters for better dimensional accuracy in stereolithography process.

Chockalingam, K.; Jawahar, N.; Vijaybabu, E. R.

2003-10-01

99

Two photon absorption coefficients and processing parameters for photoresists  

Microsoft Academic Search

The two photon absorption (TPA) process is currently used to write high resolution microstructures for a variety of applications.\\u000a Key parameters required to predict the final structure formation for this process are experimentally determined and reported\\u000a in this article for two commercially available resists, Ormocore and SU-8. The measured TPA coefficients measured at 800 nm\\u000a for Ormocore and SU-8 are 27 ? 6

Zahidur R. Chowdhury; Robert Fedosejevs

2008-01-01

100

Spray automated balancing of rotors - How process parameters influence performance  

NASA Technical Reports Server (NTRS)

This paper addresses the application of spray-automated balancing of rotors, and the influence that various operating parameters will have on balancing performance. Spray-automated balancing uses the fuel-air repetitive explosion process to imbed short, discrete bursts of high velocity, high temperature powder into a rotating part at an angle selected to reduce unbalance of the part. The shortness of the burst, the delay in firing of the gun, the speed of the disk and the variability in speed all influence the accuracy and effectiveness of the automated balancing process. The paper evaluates this influence by developing an analytical framework and supplementing the analysis with empirical data obtained while firing the gun at a rotating disk. Encouraging results are obtained, and it is shown that the process should perform satisfactorily over a wide range of operating parameters. Further experimental results demonstrate the ability of the method to reduce vibration levels induced by mass unbalance in a rotating disk.

Smalley, A. J.; Baldwin, R. M.; Fleming, D. P.; Yuhas, J. S.

1989-01-01

101

a Study of the Mechanical Characteristics of Ultrasonic Cold Forged SKD61  

NASA Astrophysics Data System (ADS)

Ultrasonic Cold Forging (UCF) technology is a method that to induces intensive plastic deformation on a material surface, so that the structure of the material becomes very fine from the surface to a certain depth. It improves the mechanical properties, hardness, compressive residual stress, and the wear and fatigue characteristics of the surface. In this study, UCF technology is applied to a cutting tool on a rolling process at a steel mill. At first, the ultrasonic cold forged specimens of SKD-61 are prepared and tested to verify the effects of UCF technology with regard to the mechanical properties, UCF is applied to the trimming knives of the cold rolling process. It is found that UCF improves the mechanical properties effectively and it is a pratical method that can improve the service time needed for the trimming knives. The productivity of the cold rolling process can be increased by the application of the ultrasonic cold forged trimming knives.

Suh, Chang-Min; Song, Gil-Ho; Park, Hae-Doo; Pyoun, Young Shick

102

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

103

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

104

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

105

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

106

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

107

76 FR 168 - Heavy Forged Hand Tools From China  

Federal Register 2010, 2011, 2012, 2013

...731-TA-457-A-D (Third Review)] Heavy Forged Hand Tools From China AGENCY: United States...antidumping duty orders on heavy forged hand tools from China...antidumping duty orders on heavy forged hand tools from China would be likely to...

2011-01-03

108

76 FR 50755 - Heavy Forged Hand Tools From China  

Federal Register 2010, 2011, 2012, 2013

...731-TA-457-A-D (Third Review)] Heavy Forged Hand Tools From China Determinations On the...antidumping duty orders on heavy forged hand tools from China would be likely to lead...August 2011), entitled Heavy Forged Hand Tools From China: Investigation...

2011-08-16

109

Hardening behaviour law versus rigid perfectly plastic law: application to a cold forging tool steel  

Microsoft Academic Search

A hardening stress strain law is determined for the AISI M2 cold forging tool steel. The experimental part is based on the Brinell indentation test. The numerical part consists in the simulation of the Brinell indentation test under increasing load cases. For each load case, parameters of the behaviour law are adjusted in order to make the numerical diameter of

A Verleene; L Dubar; A Dubois; M Dubar; J Oudin

2002-01-01

110

Wear Characteristics of cu Ofhc Material Prepared by Orbital Forging and Ecap  

NASA Astrophysics Data System (ADS)

The paper is focused on the wear mechanism of orbital forged and equal-channel angular extruded Cu OFHC (oxygen-free high thermal conductivity) material. The wear behaviour of the Cu OFHC material is investigated through pin-on-disc tests. Two different processing conditions have been used, equal-channel angular processing (ECAP) and orbital (radial) forging. The wear investigations in this orbital formed material are unique; additionally wear properties show interesting wear characteristics. Particular attention has also been paid to the friction coefficient and to the role of the wear rate.

Bidulský, R.; Actis Grande, M.; Bidulská, J.; Kva?kaj, T.; Doni?, T.

111

A new material for cold forging tools  

Microsoft Academic Search

A new tool material for cold forging applications was developed using numerical simulation techniques (FEM) for the design and a powder metallurgical route (HIP) for the production. The basic idea was to find an optimized microstructure of the two phase material by simulating different distributions of hard particles within the metal matrix. On the micro-scale, loading was applied by a

H. Berns; A. Melander; D. Weichert; N. Asnafi; C. Broeckmann; A. Gro?-Weege

1998-01-01

112

Fatigue life of cold-forging dies with various values of hardness  

Microsoft Academic Search

Four selected die materials commonly used in the cold-forging process were examined in the present study to obtain the relationship between the hardness and the die fatigue life. The die materials were first heat-treated by a developed process to obtain different values of hardness, while the ductility was retained at a favorable level. The material properties of these die materials

Yi-Che Lee; Fuh-Kuo Chen

2001-01-01

113

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

114

Decomposition of forging die for high speed machining  

E-print Network

Today's forging die manufacturing process must be adapted to several evolutions in machining process generation: CAD/CAM models, CAM software solutions and High Speed Machining (HSM). In this context, the adequacy between die shape and HSM process is in the core of machining preparation and process planning approaches. This paper deals with an original approach of machining preparation integrating this adequacy in the main tasks carried out. In this approach, the design of the machining process is based on two levels of decomposition of the geometrical model of a given die with respect to HSM cutting conditions (cutting speed and feed rate) and technological constrains (tool selection, features accessibility). This decomposition assists machining assistant to generate an HSM process. The result of this decomposition is the identification of machining features.

Tapie, Laurent

2009-01-01

115

Identification of optimum process parameters for hot extrusion using finite element simulation and processing maps  

NASA Astrophysics Data System (ADS)

The mechanical properties of a processed material depend to a great extent on the microstructural evolution during hot working. A thorough understanding of the various metallurgical processes with respect to the process parameters, namely temperature and strain rate are essential to decide the optimum parameters of processing. An attempt is made in this study to use the predictions of a processing map developed based on dynamic materials model and finite element simulation of the hot extrusion process to identify the optimum processing conditions. In the present simulation, a two-dimensional, axisymmetric, non-isothermal, rigid-plastic analysis was employed for the billet and the extrusion tooling, namely the ram and the container were considered as rigid bodies. The distribution of strains and strain rates in hot extrusion were predicted using a finite element analysis package (Marc 2000). This paper discusses the use of a processing map with the output of the finite element analysis to design the process.

Sivaprasad, P. V.; Venugopal, S.; Davies, C. H. J.; Prasad, Y. V. R. K.

2004-03-01

116

Correlations of Melt Pool Geometry and Process Parameters During Laser Metal Deposition by Coaxial Process Monitoring  

NASA Astrophysics Data System (ADS)

One major demand of today's laser metal deposition (LMD) processes is to achieve a fail-save build-up regarding changing conditions like heat accumulations. Especially for the repair of thin parts like turbine blades is the knowledge about the correlations between melt pool behavior and process parameters like laser power, feed rate and powder mass stream indispensable. The paper will show the process layout with the camera based coaxial monitoring system and the quantitative influence of the process parameters on the melt pool geometry. Therefore the diameter, length and area of the melt pool are measured by a video analytic system at various parameters and compared with the track wide in cross-sections and the laser spot diameter. The influence of changing process conditions on the melt pool is also investigated. On the base of these results an enhanced process of the build-up of a multilayer one track fillet geometry will be presented.

Ocylok, Sörn; Alexeev, Eugen; Mann, Stefan; Weisheit, Andreas; Wissenbach, Konrad; Kelbassa, Ingomar

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

On-line estimation of concentration parameters in fermentation processes*  

PubMed Central

It has long been thought that bioprocess, with their inherent measurement difficulties and complex dynamics, posed almost insurmountable problems to engineers. A novel software sensor is proposed to make more effective use of those measurements that are already available, which enable improvement in fermentation process control. The proposed method is based on mixtures of Gaussian processes (GP) with expectation maximization (EM) algorithm employed for parameter estimation of mixture of models. The mixture model can alleviate computational complexity of GP and also accord with changes of operating condition in fermentation processes, i.e., it would certainly be able to examine what types of process-knowledge would be most relevant for local models’ specific operating points of the process and then combine them into a global one. Demonstrated by on-line estimate of yeast concentration in fermentation industry as an example, it is shown that soft sensor based state estimation is a powerful technique for both enhancing automatic control performance of biological systems and implementing on-line monitoring and optimization. PMID:15909338

Xiong, Zhi-hua; Huang, Guo-hong; Shao, Hui-he

2005-01-01

119

Effect of isothermal forging on microstructure and fatigue behavior of blended elemental Ti-6Al-4V powder compacts  

NASA Astrophysics Data System (ADS)

The effect of isothermal hot forging (IHF) on microstructure, pore closure, and tensile and fatigue properties of Ti-6A1-4V blended elemental cold pressed and sintered powder compacts was investigated. Two types of sponge fines were used: (a) high chloride produced by the Hunter sodium reduction process (HP) and (b) low chloride produced by the electrolytic process (EP). The as-sintered HP compacts were 99 pct dense while the EP compacts were only 92 pct dense. All sintered preforms were isothermally hot forged below the beta transus temperature and reached almost full density. The microstructure of the HP forged compacts consisted of fine equiaxed alpha, while the EP forged compacts exhibited a coarse lenticular alpha structure after 30 pct reduction and a partially recrystallized structure after 68 pct reduction. It was found that EP compacts forged to a 30 pct reduction exhibited a low fatigue limit of 172 MPa (25 ksi), since the lenticular alpha morphology and the residual porosity resulted in premature fatigue crack initiation. On the other hand, a higher fatigue strength of 485 MPa (70 ksi) was obtained for EP compacts forged to a 78 pct reduction due to the mixed equiaxed/lenticular alpha morphology as well as removal of stress concentration features such as interparticle pore interfaces.

Weiss, I.; Eylon, D.; Toaz, M. W.; Froes, F. H.

1986-03-01

120

Effect of isothermal forging on microstructure and fatigue behavior of blended elemental Ti-6Al-4V powder compacts  

SciTech Connect

The effect of isothermal hot forging (IHF) on microstructure, pore closure, and tensile and fatigue properties of Ti-6Al-4V blended elemental cold pressed and sintered powder compacts was investigated. Two types of sponge fines were used: (1) chloride produced by the Hunter sodium reduction process (HP) and (2) low chloride produced by the electrolytic process (EP). The as-sintered HP compacts were 99 pct dense while the EP compacts were only 92 pct dense. All sintered preforms were isothermally hot forged below the beta transus temperature and reacted almost full density. The microstructure of the HP forged compacts consisted of fine equiaxed alpha, while the EP forged compacts exhibited a coarse lenticular alpha structure after 30 pct reduction and a partially recrystallized structure after 68 pct reduction. It was found that EP compacts forged to a 30 pct reduction exhibited a low fatigue limit of 172 MPa (25 ksi), since the lenticular alpha morphology and the residual porosity resulted in premature fatigue crack initiation. On the other hand, a higher fatigue strength of 485 MPa (70 ksi) was obtained for EP compacts forged to a 78 pct reduction due to the mixed equiaxed/lenticular alpha morphology as well as removal of stress concentration features such as interparticle pore interfaces. 26 references.

Weiss, I.; Eylon, D.; Toaz, M.W.; Froes, F.H.

1986-03-01

121

Optimization of drying process parameters for cauliflower drying.  

PubMed

The different sizes (3, 4 and 5 cm) of hybrid variety of cauliflower (variety no. 71) were dehydrated in thin layer at three temperatures of 55, 60 and 65 °C with velocities of 40, 50 and 60 m/min. Dehydrated samples were analyzed for vitamin C, rehydration ratio and browning. Statistical analysis indicated that drying time was dependent on initial size of cauliflower, drying air temperature and velocity, but rehydration ratio was significantly affected by the combined effect of temperature and airflow velocity. Vitamin C content of the dried cauliflower samples were significantly affected by temperature only and non enzymatic browning was function of temperature, airflow velocity, and combined effect of temperature and airflow velocity. Optimization of the drying process parameters for the given constraints resulted in 60.10(0)C, 59.28 m/min, 3.35 cm. The predicted responses for the optimized combination of process parameters were time, vitamin C content, rehydration ratio, and browning values of 491.22 min (time), 289.86 mg/100 g (Vitamin C), 6.91 ( rehydration ratio), and 0.14 (browning), respectively with the desirability factor of 0.787. PMID:24425888

Gupta, Manoj Kumar; Sehgal, V K; Arora, Sadhna

2013-02-01

122

Fundamental aspects for the evaluation of the fatigue behaviour of cold forging tools  

Microsoft Academic Search

The service life of cold forging tools is mainly limited by high-cycle fatigue (HCF). The prediction of the expectable tool life is an essential precondition for an optimisation of the tool resistance against fatigue and the evaluation of optimisation measures during early design stages. In this context, the numerical process simulation (primarily the finite element method) enables the calculation of

B. Falk; U. Engel; M. Geiger

2001-01-01

123

An Inverse Approach for the Design of the Optimal Preform Shape in Cold Forging  

Microsoft Academic Search

In closed die forging the preform design plays a critical role for the success of the process: in fact it must ensure that in the finishing step the desired product is obtained without shape defects such as underfilling or folding and with a minimum material loss into the flash. In the paper an inverse approach is applied to the preform

R. Di Lorenzo; F. Micari

1998-01-01

124

Simulation model for hot and cold forging by mixed methods including adaptive mesh refinement  

Microsoft Academic Search

Uses a rigid viscoplastic formulation to simulate hot and cold forging processes. The finite element solution uses mixed methods in which the independent variables can be velocities, pressures and deviatoric stresses. Uses interface elements both in the mechanical and the thermal analysis, to take into account the effects of contact and friction, thermal conductivity of lubricants and heat generated by

J. César de Sá; Luisa Costa Sousa; Maria Luisa Madureira

1996-01-01

125

Fatigue and mechanical characteristics of nano-structured tool steel by ultrasonic cold forging technology  

Microsoft Academic Search

Ultrasonic cold forging technology (UCFT) utilizing ultrasonic vibration energy is a method to induce severe plastic deformation to a material surface, therefore, the structure of the material surface becomes a nano-crystal structure from the surface to a certain depth. It improves the mechanical properties; hardness, compressive residual stress, wear and fatigue characteristics. Applying UCFT to a rolling process in the

Chang-Min Suh; Gil-Ho Song; Min-Soo Suh; Young-Shik Pyoun

2007-01-01

126

Evaluation of friction condition in cold forging by using T-shape compression test  

Microsoft Academic Search

Friction plays an important role in metal forming, and numerical simulation of forging processes requires precise informations about the material properties and the value of the friction factor m or coefficient ?. This paper describes the T-shape compression, a new friction testing method by combined compression and extrusion of a cylinder between a flat punch and a V-grooved die. It

Q. Zhang; E. Felder; S. Bruschi

2009-01-01

127

Fracture of Magnesium Alloy in Cold Forging  

Microsoft Academic Search

In order to clarify the forming limit of magnesium alloy in cold forging, the workability of magnesium alloy AZ31B (Mg-3%Al-1%Zn) is examined by upsetting and backward extrusion. In the upsettability test, shear type fracture occurs at a small equivalent strain of about 0.15 at temperatures lower than 170°C. At a higher temperature, the flow stress curve has a peak at

R. Matsumoto; T. Kubo; K. Osakada

2007-01-01

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 perils and pitfalls of mining SourceForge  

Microsoft Academic Search

SourceForge provides abundant accessible data from Open Source Software development projects, making it an attractive data source for software engineering research. However it is not without theoretical peril and practical pit- falls. In this paper, we outline practical lessons gained from our spidering, parsing and analysis of SourceForge data. SourceForge can be practically difficult: projects are de- funct, data from

James Howison; Kevin Crowston

2004-01-01

130

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.

131

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

132

Analysis of process parameters of micro fluid-jet polishing on the processing effect  

NASA Astrophysics Data System (ADS)

Micro fluid-jet polishing technology is a new kind of ultra-smooth machining method which proposed on the basis of float polishing principle and combined with small tool polishing. This article will use micro jet ultra-smooth machine which developed by ourselves to develop the process experiment for plane elements. In the experiment, the material removal rate and surface roughness are taken as the assessment index, and the orthogonal experiment method is used to study the processing effect of different process parameters, such as the spindle speed, the pressure of the grinding head and the abrasive concentration. On the basis of the experimental results and combined with the micro jet polishing mechanism, the processing effect law of the various process parameters is analyzed. It shows that, the influence of polishing pressure and abrasive concentration on the removal efficiency is single, that is to say, the removal efficiency can be increased either by increasing the polishing pressure or by increasing the concentration of the slurry. However, the influence of the grinding speed on removal efficiency is not simple, the removal efficiency can be increased by increasing the grinding speed in the certain range, if continue to increase, the removal efficiency will decrease. The influence of the process parameters on the roughness is more complex, but it can be summarized grossly as follows: if the roughness is required to reduce quickly, the large polishing pressure and high concentration slurry can be chosen, but it has a large depth of removal; if the roughness is required to reduce and the removal depth is as small as possible, the little polishing pressure and the dilute polishing liquid can be chosen, but it has a long polishing time. So in the actual processing, the process parameters should be adjusted according to different machining needs, to finally reach the optimization.

Wang, Shaozhi; Liu, Jian; Zhang, Linghua

2013-08-01

133

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

Federal Register 2010, 2011, 2012, 2013

...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

134

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

Federal Register 2010, 2011, 2012, 2013

...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

135

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

Federal Register 2010, 2011, 2012, 2013

...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

136

Effects of process parameters in plastic, metal, and ceramic injection molding processes  

NASA Astrophysics Data System (ADS)

Plastic injection molding has been widely used in the past and is a dominant forming approach today. As the customer demands require materials with better engineering properties that were not feasible with polymers, powder injection molding with metal and ceramic powders has received considerable attention in recent decades. To better understand the differences in the plastic injection molding, metal injection molding, and ceramic injection molding, the effects of the core process parameters on the process performances has been studied using the state-of-the-art computer-aided engineering (CAE) design tool, PIMSolver® The design of experiments has been conducted using the Taguchi method to obtain the relative contributions of various process parameters onto the successful operations.

Lee, Shi W.; Ahn, Seokyoung; Whang, Chul Jin; Park, Seong Jin; Atre, Sundar V.; Kim, Jookwon; German, Randall M.

2011-09-01

137

Analysis and prevention of cracking phenomenon occurring during cold forging of two AISI 1010 steel pulleys  

Microsoft Academic Search

This study is concerned with the effects of microstructural parameters on the cracking phenomenon occurring during cold forging\\u000a of two AISI 1010 steels that were fabricated by converter steel making and electric furnace steel making, respectively. This\\u000a allowed a comparison between microstructures that contained a small or large amount of nitrogen. Detailed microstructural\\u000a analyses of the cracked region showed that

Dong-Kuk Kim; Suk Young Kang; Sunghak Lee; Kyung Jong Lee

1999-01-01

138

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

139

Cold forging of sintered iron-powder preforms  

Microsoft Academic Search

The paper reports on an investigation into various aspects of cold forging of iron-powder preforms which have been compacted and sintered from atomised iron powder. An upperbound solution is constructed for determining the die pressures developed during the cold forging of iron powder under axisymmetric and plane-strain condition. The results so obtained are discussed critically to illustrate the interaction of

G. Sutradhar; A. K. Jha; S. Kumar

1995-01-01

140

Finite element analysis of prestressed die set in cold forging  

Microsoft Academic Search

An application-oriented finite-element approach to forging die structural analysis is presented in this paper. The die set structural analysis problem is formulated as a contact problem with both shrink fit and preloaded clamping considered, solved iteratively by a varying penalty method. The loading condition is extracted automatically from forging simulation. A predicted solution is compared with analytical one and two

M. S. Joun; M. C. Lee; J. M. Park

2002-01-01

141

On the utilisation of ductile fracture criteria in cold forging  

Microsoft Academic Search

In most cold forging operations, formability is limited by ductile fracture. This paper describes the utilisation of ductile fracture criteria in conjunction with the finite element method to predict when and where material is likely to fracture during cold forging. Several previously published ductile fracture criteria are selected, and their values of critical damage at the levels of deformation at

J Landre; A Pertence; P. R Cetlin; J. M. C Rodrigues; P. A. F Martins

2003-01-01

142

Process Parameters for Infrared Processing of FePt Nanoparticle Films  

NASA Astrophysics Data System (ADS)

Pulse thermal processing (PTP) of FePt nanoparticle films was studied using a high density infrared (HDI) plasma arc lamp. FePt nanoparticle films on silicon substrates were processed using 0.25- second infrared (IR) pulses. The processing was aimed at reaching a peak target temperature for multiple pulses of 550 °C. Numerical simulations of the heat transfer for the PTP were performed to determine the operating power levels for the plasma arc lamp. Infrared measurements were conducted to obtain experimental data for the surface temperature of the FePt nanofilm. Parameters needed for the heat-transfer model were identified based on the experimental temperature results. Following the model validation, several numerical simulations were performed to estimate the power levels. It was shown that the FePt nanoparticle films were successfully processed using the power levels provided by the heat-transfer analysis.

Sabau, Adrian S.; Kadolkar, Puja B.; Dinwiddie, Ralph B.; Ott, Ronald D.; Blue, Craig A.

2007-04-01

143

Investigation on process parameters of flexible stretch forming process using orthogonal experiment design  

NASA Astrophysics Data System (ADS)

The flexible stretch forming process (FSFP), is useful sheet metal forming method to produce the small batch three dimensional surfaces. Elastic recovery is one of the very important factors to influence the shape accuracy. The main purpose of this paper is to investigate the influence of design parameters on the elastic recovery. The prestrain, the punch size, the objective radius of surface and thickness of the elastic pad are selected as the design parameters. The value of elastic recovery is selected to evaluate the shape accuracy. The orthogonal experiment design is adopted to investigate the relationship between shape accuracy and design parameters. The analysis of variances (ANOVA) is applied to analyze the value of elastic recovery. The optimal combination is PS3R3PR2T2, which is 0.01 for the prestrain, 500mm for the objective surface radius, 10mm for punch radius and 5mm for elastic pad thickness. The orthogonal experiment design and ANOVA approach may provide a useful guidance to determine design parameters and improve the forming quality in FSFP.

Liu, Pan; Ku, Tae-Wan; Kim, Jeong; Kang, Beom-Soo

2013-12-01

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

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

146

Mechanical behavior of cast and forged magnesium alloys and their microstructures  

Microsoft Academic Search

Effects of manufacturing processes on microstructure and mechanical properties of magnesium alloys AM60 and AZ31B were investigated. The magnesium alloy AM60 was produced by high-pressure die cast (HPDC) with two different casting processors but AZ31B was produced by forging. Casting defects were investigated with SEM observations for the specimens obtained from the two casting processors. The fatigue tests were conducted

Hong Tae Kang; Terry Ostrom

2008-01-01

147

Optimization of spray quenching for aluminum extrusion, forging, or continuous casting  

Microsoft Academic Search

A review of the current understanding of heat transfer from quenched alloy products to water sprays is presented. A numerical\\u000a example is described to demonstrate how controlled spray cooling of products containing sections of differing thicknesses\\u000a significantly reduces thermal gradients. A semi-expert computer-aided design (CAD) system is proposed for optimizing the process\\u000a of spray quenching following extrusion, forging, or continuous

T. A. Deiters; I. Mudawar

1989-01-01

148

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

149

Towards Ubiquitous Acquisition and Processing of Gait Parameters  

Microsoft Academic Search

\\u000a Gait analysis is the process of measuring and evaluating gait and walking spatio-temporal patterns, namely of human locomotion.\\u000a This process is usually performed on specialized equipment that is capable of acquiring extensive data and providing a gait\\u000a analysis assessment based on reference values. Based on gait assessments, therapists and physicians can prescribe medications\\u000a and provide physical therapy rehabilitation to patients

Irvin Hussein López-Nava; Angélica Muñoz-Meléndez

2010-01-01

150

Critical current densities in Bi-2223 sinter forgings.  

SciTech Connect

(Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) bars, prepared by sinter forging, exhibited good phase purity and strong textures with the c axes of the Bi-2223 grains parallel to the forging direction. The initial zero-field critical current density (J{sub c}) of the bars was 10{sup 3} A/cm{sup 2}, but because the forged bars were uncoated, this value decreased with repeated thermal cycling. J{sub c} as a function of applied magnetic field magnitude and direction roughly followed the dependencies exhibited by Ag-sheathed Bi-2223 tapes, but the forged bars were more strongly dependent on field strength and less strongly dependent on field angle.

Balachandran, U.; Fisher, B. L.; Goretta, K. C.; Harris, N. C.; Murayama, N.

1999-07-23

151

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

152

Individual Cognitive Parameter Setting Based on Black Stork Foraging Process  

Microsoft Academic Search

Abstract—Cognitive learning factor is an important param- eter in particle swarm optimization algorithm(PSO). Although many selection strategies have been proposed, there is still much work need to do. Inspired by the black stork foraging process, this paper designs a new cognitive selection strategy, in which the whole swarm is divided into adult and infant particle, and each kind particle has

Zhihua Cui

2009-01-01

153

PROCESS PLANNING METHOD FOR MASK PROJECTION STEREOLITHOGRAPHY UNDER PARAMETER UNCERTAINTY  

Microsoft Academic Search

Summary Mask Projection Stereolithography (MPSLA) is a high resolution, additive manufacturing process, which has potential applications in a number of areas like MEMS packaging, tissue scaffolding, micro fluidics, etc. The MPSLA technology is only about a decade old and so, most research in this field has been experimental in nature. In this proposal, a plan to analytically model the MPSLA

AMEYA LIMAYE

154

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

155

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

156

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

157

Influence of processing parameters on morphology of polymethoxyflavone in emulsions.  

PubMed

Polymethoxyflavones (PMFs) are groups of compounds isolated from citrus peels that have been documented with wide arrays of health-promoting bioactivities. Because of their hydrophobic structure and high melting point, crystallized PMFs usually have poor systemic bioavailability when consumed orally. To improve the oral efficiency of PMFs, a viscoelastic emulsion system was formulated. Because of the crystalline nature, the inclusion of PMFs into the emulsion system faces great challenges in having sufficient loading capacity and stabilities. In this study, the process of optimizing the quality of emulsion-based formulation intended for PMF oral delivery was systematically studied. With alteration of the PMF loading concentration, processing temperature, and pressure, the emulsion with the desired droplet and crystal size can be effectively fabricated. Moreover, storage temperatures significantly influenced the stability of the crystal-containing emulsion system. The results from this study are a good illustration of system optimization and serve as a great reference for future formulation design of other hydrophobic crystalline compounds. PMID:25537008

Ting, Yuwen; Li, Colin C; Wang, Yin; Ho, Chi-Tang; Huang, Qingrong

2015-01-21

158

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

159

BIOPHYSICAL PARAMETER ESTIMATION WITH ADAPTIVE GAUSSIAN PROCESSES G. Camps-Valls1  

E-print Network

BIOPHYSICAL PARAMETER ESTIMATION WITH ADAPTIVE GAUSSIAN PROCESSES G. Camps-Valls1 , L. G) for the estimation of biophysical parameters from acquired multispectral data. The standard GP formulation is used membrane state confirm GPs as adequate, alternative non- parametric methods for biophysical parameter

Camps-Valls, Gustavo

160

Optimization of process parameters for ultrasonic drilling of advanced engineering ceramics using the Taguchi approach  

Microsoft Academic Search

The effect of process parameters on the cutting ratio (ratio of material removal rate to tool wear rate) for ultrasonic drilling of alumina-based ceramics using silicon carbide abrasive was studied. The parameters considered were workpiece material, tool material, grit size of the abrasive, power rating, and slurry concentration. Taguchi’s optimization approach was used to obtain the optimal parameters. The significant

R. S. Jadoun; Pradeep Kumar; B. K. Mishra; R. C. S. Mehta

2006-01-01

161

Cycle Time Reduction for Optimization Of Injection Molding Machine Parameters for Process Improvement  

Microsoft Academic Search

Injection molding is a worldwide business that companies around the world use as a predominant method in manufacturing. Optimizing the parameters of the injection molding machine is critical to improve manufacturing processes. This research focuses on the optimization of injection molding machine parameters using one material. Suggestions for process improvements are made based on the results of a designed experiment.

James Henderson; Aaron K. Ball; James Z. Zhang

162

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

163

Non-destructive Testing of Forged Metallic Materials by Active Infrared Thermography  

NASA Astrophysics Data System (ADS)

Nowadays, infrared thermography is considered as the reference method in many applications such as safety, the inspection of electric installations, or the inspection of buildings' heat insulation. In recent years, the evolution of both material and data-processing tools also allows the development of thermography as a real non-destructive testing method. Thus, by subjecting the element to be inspected to an external excitation and by analyzing the propagation of heat in the examined zone, it is possible to highlight surface or subsurface defects such as cracks, delaminations, or corrosion. One speaks then about active infrared thermography. In this study, some results obtained during the collective studies carried out by CETIM and the University of Reims for the forging industry are presented. Various experimental possibilities offered by active thermography are presented and the interest in this method in comparison with the traditional non-destructive testing methods (penetrant testing and magnetic particle inspection) is discussed. For example, comparative results on a forged cracked hub, a steering joint, and a threaded rod are presented. They highlight the interest of infrared thermography stimulated by induction for forged parts.

Maillard, S.; Cadith, J.; Bouteille, P.; Legros, G.; Bodnar, J. L.; Detalle, V.

2012-11-01

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

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

166

Analysis of Leaf Parameters Measurement of Cucumber Based on Image Processing  

Microsoft Academic Search

This paper discusses image processing is carried on measuring cucumber leaf parameters. Leaf area of cucumber is determined with image processing, which results are compared with the results of grid counting, paper weighing and leaf area meter method. Leaf maximum length and leaf maximum width of cucumber are determined with image processing, which results are compared with the results of

You-wen Tian; Xiao-juan Wang

2009-01-01

167

Advancements in on-line monitoring and control of parameters in knitting and sewing processes  

Microsoft Academic Search

This paper presents a summary of the developments in process control in textile processes at the University of Minho, by a multidisciplinary research group involving three different departments (Textile, Electronic and Mechanical Engineering). The studies target the automatic process parameter monitoring and control in the areas of industrial sewing and knitting.

Helder Carvalho; André Catarino; Miguel Carvalho; Luís Silva; Fernando Ferreira; Ana Rocha; João Monteiro; Filomena Soares

168

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

169

ME 6222: Manufacturing Processes and Systems Prof. J.S. Colton GIT 2011  

E-print Network

Processes and Systems Prof. J.S. Colton © GIT 2011 9 Characteristics · Similar to closed die forging · Forging ­ slug (bulk) is forging ­ flash (extrusion) is waste · Extrusion ­ extrusion (flash) is part Types · Direct · Indirect · Tubular · Hydrostatic · Cold Impact #12;ME 6222: Manufacturing Processes

Colton, Jonathan S.

170

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

171

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

172

Process Parameters and Energy Use of Gas and Electric Ovens in Industrial Applications  

E-print Network

of sintering billets which are made from a broad range of materials such as PTFE and other fluoropolymers, elastomers, themosets, themoplastics and composites. The purpose of this study was to compare the process parameters under similar conditions...

Kosanovic, D.; Ambs, L.

173

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...

174

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

E-print Network

The main goal of this research is to estimate the model parameters and to detect multiple change points in the long memory parameter of Gaussian ARFIMA(p, d, q) processes. Our approach is Bayesian and inference is done on wavelet domain. Long memory...

Ko, Kyungduk

2005-11-01

175

Short Note Impact of Earthquake Rupture Extensions on Parameter Estimations of Point-Process Models  

Microsoft Academic Search

Online Material: Sensitivity to scaling of the d-parameter and to inhomogeneous background activity, and possible correlation between the largest magnitude and es- timated ?-value. Abstract Stochastic point processes are widely applied to model spatiotemporal earthquake occurrence. In particular, the epidemic type aftershock sequence (ETAS) model has been shown to successfully reproduce the short-term clustering of earth- quakes. An important parameter

S. Hainzl; A. Christophersen; B. Enescu

2008-01-01

176

High-temperature mechanical properties of sinter-forged silicon nitride with ytterbia additive  

Microsoft Academic Search

Anisotropic silicon nitride with ytterbia additive was successfully fabricated by using a sinter-forging technique. The sinter-forged specimen had a strongly anisotropic microstructure where rod-like silicon nitride grains preferentially aligned perpendicular to the forging direction. The specimen exhibited higher strength and higher fracture energy compared to the conventionally hot-pressed specimen. These superior mechanical properties of the sinter-forged silicon nitride were attributed

Naoki Kondo; Yoshikazu Suzuki; Tatsuya Miyajima; Tatsuki Ohji

2003-01-01

177

Application of L cr Waves to Evaluate Residual Stresses in the RIM of Railroad Forged Wheels  

Microsoft Academic Search

The process of manufacturing wrought railroad wheels consists of forging heated blocks of steel, which are machined, heated,\\u000a and quenched to reach the correct level of the mechanical properties to be used in railroads. The process generates compressive\\u000a hoop stresses in the wheel rim. In field conditions, the original stress pattern can be changed mainly by overheating, which\\u000a is caused

Auteliano A. Santos; Guilherme F. M. dos Santos; Francisco C. de Santos; Marcilio H. Andrino; João M. Rosário

2009-01-01

178

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

Federal Register 2010, 2011, 2012, 2013

...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

179

Optimizing Friction Stir Welding via Statistical Design of Tool Geometry and Process Parameters  

NASA Astrophysics Data System (ADS)

This article considers optimization procedures for friction stir welding (FSW) in 5083-H321 aluminum alloy, via control of weld process parameters and tool design modifications. It demonstrates the potential utility of the "force footprint" (FF) diagram in providing a real-time graphical user interface (GUI) for process optimization of FSW. Multiple force, torque, and temperature responses were recorded during FS welding using 24 different tool pin geometries, and these data were statistically analyzed to determine the relative influence of a number of combinations of important process and tool geometry parameters on tensile strength. Desirability profile charts are presented, which show the influence of seven key combinations of weld process variables on tensile strength. The model developed in this study allows the weld tensile strength to be predicted for other combinations of tool geometry and process parameters to fall within an average error of 13%. General guidelines for tool profile selection and the likelihood of influencing weld tensile strength are also provided.

Blignault, C.; Hattingh, D. G.; James, M. N.

2012-06-01

180

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

181

Phase Evolution in Fe-Mn-Si Shape Memory Alloys due to Forging Speed  

NASA Astrophysics Data System (ADS)

The objective of this investigation is to compare the crystallographic characteristics of two different compositions of Fe-Mn-Si alloys forged with the newly designed and constructed High Energy Rate Forming (HERF) hammer with conventional hydraulic and mechanical presses. The degree of martensite formation may depend on metal forming conditions. For both of the alloys, one of the specimens was investigated in as "prepared form", the other specimen was investigated after air cooling with homogenization treatment and three specimens were deformed in different velocities after homogenization treatments. The changes which occurred in the transformation parameters of two FeMnSi alloys with different compositions due to the effects of thermal and mechanical procedures have been studied by using X-ray diffraction. In the alloy specimens cooled to different conditions from the high-temperature ? phase region, ??? and ?????? martensitic transformations were observed. The lattice parameters (LP) of fcc ? and hcp ? structures were determined, and changes in forging speed on the LPs were found.

Eskil, Murat; Kanca, Erdogan

2013-09-01

182

Experimental analysis of nano-structured materials forging by using plane-shape dies  

NASA Astrophysics Data System (ADS)

In recent years some severe plastic deformation processes have been developed with the aim of obtaining a material with micrometric grain size or even nanometric, such as: ECAE (Equal channel angular extrusion), HPT (High pressure torsion) and CCDR (Continuous combined drawing and rolling), among others. The aim of this work is to study the forging of the 5083 aluminium alloy, previously deformed plastically by ECAE using plane shape dies. This will be done at different temperatures measuring the final properties of the obtained material. A comparison with the AA 5083 full annealed, without ECAE deformation, will be made.

Puertas, I.; Luis, C. J.; Salcedo, D.; Pérez, I.

2012-04-01

183

Process parameter influence on performance of friction taper stud welds in AISI 4140 steel  

Microsoft Academic Search

Friction taper stud welding is a new variant of friction welding which has been developed from the principles of friction hydro-pillar processing. This paper considers the effect of weld process parameters on weld defects, macrostructure and mechanical properties in AISI 4140 steel. It also presents 3D residual stress data for a typical friction taper stud weld. Applied downwards force, rotational

D. G. Hattingh; D. L. H. Bulbring; A. Els-Botes; M. N. James

2011-01-01

184

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.

185

16. Forge building and fuel storage shed from the southwest, ...  

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

16. Forge building and fuel storage shed from the southwest, c.1918 Photocopied from a photograph in the collection of William F. Applegate, 43 Grandview Avenue, Wallingford, Connecticut. - Eli Whitney Armory, West of Whitney Avenue, Armory Street Vicinity, Hamden, New Haven County, CT

186

Forging an Identity over the Life-Course  

ERIC Educational Resources Information Center

Using a social constructionist approach, this study explores the self-perceptions of young men who, when at school, were classed as boys with social, emotional and behavioural difficulties (SEBD). The aim is to understand how these perceptions were forged throughout the young men's life-courses resulting in changing self-identities. The study also…

Spiteri, Damian

2009-01-01

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

Cold forging of gears: experimental and theoretical investigation  

Microsoft Academic Search

This paper draws from fundamental research on precision forging for the development of a flexible tool system for producing gear parts. The overall investigation makes use of conventional spur gears. Fundamental research is undertaken by using virtual prototyping modeling techniques based on the finite element method. The utilization of such techniques provides a better insight into the deformation mechanics during

M. L Alves; J. M. C Rodrigues; P. A. F Martins

2001-01-01

189

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

190

Evaluation of new cold forging lubricants without zinc phosphate precoat  

Microsoft Academic Search

Zinc phosphate coatings plus metal soap lubrication system is required in nearly all steel cold forging operations. However, the chemical byproducts of this lubricant system are difficult to dispose of and have a negative environmental impact. In order to replace zinc phosphate based lubricants partially or completely, candidate lubricants were sought from lubricant manufacturers worldwide. The performance evaluation of these

Mark Gariety; Gracious Ngaile; Taylan Altan

2007-01-01

191

Consolidation and Forging Methods for a Cryomilled Al Alloy  

NASA Astrophysics Data System (ADS)

The method used to consolidate a cryogenically ball-milled powder is critical to the retention of superior strength along with acceptable tensile ductility in the bulk product. In this study, gas-atomized Al 5083 powder was cryomilled, hot vacuum degassed, and consolidated by hot isostatic pressing (HIP) or by quasi-isostatic (QI) forging to produce low-porosity billets. The billets were then forged, either at high strain rate (without a die) or quasi-isostatically, and subsequently hot rolled to produce three 6.5-mm-thick plates. Despite extended periods at elevated temperatures and differences between the consolidation/deformation methods, a similar predominantly ultrafine grain microstructure was obtained in all three plates. The plates possessed similar ultimate tensile strengths, about 50 pct greater than standard work-hardened Al 5083. However, in terms of fracture toughness, there were significant differences between the plates. Debonding at prior cryomilled powder particle surfaces was an important fracture mechanism for “HIPped” material, leading to low toughness for crack surfaces in the plane of the plate. This effect was minimized by the implementation of double QI forging, producing plate with good isotropic fracture toughness. The type of particle boundary deformation during forging and the influence of impurities appeared to be more important in determining fracture toughness than the presence of ˜10 vol pct coarser micron-sized grains.

Newbery, A. P.; Ahn, B.; Hayes, R. W.; Pao, P. S.; Nutt, S. R.; Lavernia, E. J.

2008-09-01

192

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

193

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

194

Experimental Determination of Process Parameters and Material Data for Numerical Modeling of Induction Hardening  

NASA Astrophysics Data System (ADS)

Induction surface hardening is a widely used manufacturing process to improve the mechanical properties of components. However, better process understanding as well as process development requires numerical modeling. The modeling itself depends on the input data in terms of process parameters and the material behavior. Data acquisition is a rather difficult task due to very short processing times, as seen in contour hardening of gears. The article will give an overview over critical aspects regarding the acquisition of input data. A short presentation of the numerical model used to compare experimental and numerical results shall promote better understanding for improving the modeling or reducing the model complexity necessary for good predictability.

Schwenk, Maximilian; Hoffmeister, Jürgen; Schulze, Volker

2013-07-01

195

Mechanistic basis for the effects of process parameters on quality attributes in high shear wet granulation.  

PubMed

Three model compounds were used to study the effect of process parameters on in-process critical material attributes and a final product critical quality attribute. The effect of four process parameters was evaluated using design of experiment approach. Batches were characterized for particle size distribution, density (porosity), flow, compaction, and dissolution rate. The mechanisms of the effect of process parameters on primary granule properties (size and density) were proposed. Water amount showed significant effect on granule size and density. The effect of impeller speed was dependent on the granule mechanical properties and efficiency of liquid distribution in the granulator. Blend density was found to increase rapidly during wet massing. Liquid addition rate was the least consequential factor and showed minimal impact on granule density and growth. Correlations of primary properties with granulation bulk powder properties (compaction and flow) and tablet dissolution were also identified. The effects of the process parameters on the bulk powder properties and tablet dissolution were consistent with their proposed link to primary granule properties. Understanding the impact of primary granule properties on bulk powder properties and final product critical quality attributes provides the basis for modulating granulation parameters in order to optimize product performance. PMID:22981985

Badawy, Sherif I F; Narang, Ajit S; LaMarche, Keirnan; Subramanian, Ganeshkumar; Varia, Sailesh A

2012-12-15

196

Approach for long term environmental parameters monitoring process using data acquisition devices and high level applications for data processing  

NASA Astrophysics Data System (ADS)

Present paper describes a long term monitoring process of few environmental parameters for evaluating green energy potential (wind energy and solar energy) of a small geographical area (~ 32 km2). The monitoring approach presented in this paper consists in: real-time data acquisition process using two real-time data acquisition devices (DAQ); a wireless network used for long distance data transmission in order to send all acquired data to a remote location for processing; Virtual Instrument (VI's) applications used for controlling data acquisition devices and the acquisition process; a network protocol analyzer used for a detailed analysis of the communication protocols and data packets; the management of the huge volume of sensor data by using a high level software application; long term sensor monitoring using a complex graphic software application. The measured environment parameters are the following: wind speed, wind direction, temperature, sun intensity and illumination, steel pylon vibrations on three axes.

Croitoru, Bogdan; Boca, Loredana; Abrudean, Mihail; Joldes, Remus

2010-11-01

197

The effect of processing parameters on the propensity for central fracturing in piercing  

Microsoft Academic Search

Successful competition in the seamless tubular products market demands improvements in surface and dimensional quality in\\u000a products from seamless pipe mills. It is reported that pass design, piercer setup and operating parameters have critical effects\\u000a on both dimensional and surface quality. Defects which form during the piercing process are the result of these mechanical\\u000a parameters (which control the localized stress

Emin Erman

1987-01-01

198

Taguchi’s optimization of process parameters for production accuracy in ultrasonic drilling of engineering ceramics  

Microsoft Academic Search

This paper presents a study of the effect of process parameters on production accuracy obtained through ultrasonic drilling\\u000a of holes in alumina based ceramics using silicon carbide abrasive. Production accuracy in ultrasonic drilling involves both\\u000a dimensional accuracy (hole oversize) and form accuracy (out-of-roundness and conicity). The parameters considered are workpiece\\u000a material, tool material, grit size of the abrasive, power rating

R. S. Jadoun; Pradeep Kumar; B. K. Mishra

2009-01-01

199

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.

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

2015-01-01

200

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

201

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

202

UCMS - A new signal parameter measurement system using digital signal processing techniques. [User Constraint Measurement System  

NASA Technical Reports Server (NTRS)

The User Constraint Measurement System (UCMS) is a hardware/software package developed by NASA Goddard to measure the signal parameter constraints of the user transponder in the TDRSS environment by means of an all-digital signal sampling technique. An account is presently given of the features of UCMS design and of its performance capabilities and applications; attention is given to such important aspects of the system as RF interface parameter definitions, hardware minimization, the emphasis on offline software signal processing, and end-to-end link performance. Applications to the measurement of other signal parameters are also discussed.

Choi, H. J.; Su, Y. T.

1986-01-01

203

Intelligent Modeling Combining Adaptive Neuro Fuzzy Inference System and Genetic Algorithm for Optimizing Welding Process Parameters  

NASA Astrophysics Data System (ADS)

Modified 9Cr-1Mo ferritic steel is used as a structural material for steam generator components of power plants. Generally, tungsten inert gas (TIG) welding is preferred for welding of these steels in which the depth of penetration achievable during autogenous welding is limited. Therefore, activated flux TIG (A-TIG) welding, a novel welding technique, has been developed in-house to increase the depth of penetration. In modified 9Cr-1Mo steel joints produced by the A-TIG welding process, weld bead width, depth of penetration, and heat-affected zone (HAZ) width play an important role in determining the mechanical properties as well as the performance of the weld joints during service. To obtain the desired weld bead geometry and HAZ width, it becomes important to set the welding process parameters. In this work, adaptative neuro fuzzy inference system is used to develop independent models correlating the welding process parameters like current, voltage, and torch speed with weld bead shape parameters like depth of penetration, bead width, and HAZ width. Then a genetic algorithm is employed to determine the optimum A-TIG welding process parameters to obtain the desired weld bead shape parameters and HAZ width.

Gowtham, K. N.; Vasudevan, M.; Maduraimuthu, V.; Jayakumar, T.

2011-04-01

204

Analysis of Process Parameters Affecting Spray-Dried Oily Core Nanocapsules Using Factorial Design  

Microsoft Academic Search

The purpose of this work was to optimize the process parameters required for the production of spray-dried oily core nanocapsules\\u000a (NCs) with targeted size and drug yield using a two-level four-factor fractional factorial experimental design (FFED). The\\u000a coded process parameters chosen were inlet temperature (X\\u000a 1), feed flow rate (X\\u000a 2), atomizing air flow (X\\u000a 3), and aspiration rate (X

Tao Zhang; Bi-Botti C. Youan

2010-01-01

205

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

206

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

207

Roll Forming of AHSS: Numerical Simulation and Investigation of Effects of Main Process Parameters on Quality  

NASA Astrophysics Data System (ADS)

The roll forming process is one of the main processes of producing straight profiles in many industrial sectors. The introduction of Advanced High Strength Steels (AHSS), such as the DP and TRIP-series, into the production of roll-formed profiles has emerged new challenges. The combination of a higher yield strength with a lower total elongation of AHSS, brings new challenges to the roll forming process. In the current study, the numerical simulation of a V-section profile has been implemented. The effect of the main process parameters, such as the roll forming line velocity, rolls inter-distance, roll gap and rolls diameter on quality characteristics is investigated.

Salonitis, Konstantinos; Paralikas, John; Chryssolouris, George

208

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

209

Impacts of process parameters on CIGS solar cells prepared by selenization process with Se Vapor  

Microsoft Academic Search

The CuIn1-xGaxSe2 (CIGS) films are prepared by the selenization process including the deposition of the metal precursors followed by heating the metal precursors in a Se overpressure. The impacts of Se deposition rates on the morphology, grain growth, and atomic ratios of the resulting CIGS films are investigated. The CIGS films prepared at the high Se flow rate exhibit the

Chia-Hua Huang; Y. C. Shih; Wen-Jie Chuang; Chun-Ping Lin

2010-01-01

210

Parallel Optimization of Forging Processes for Optimal Material Properties  

E-print Network

* , Reese E. Jones+ , Kenneth J. Perano# , Tamara G. Kolda& *Sandia National Laboratories, Engineering Mechanics Modeling and Simulation Department, MS9042, PO Box 969, Livermore, CA 94550, USA + Sandia National # Sandia National Laboratories, Advanced Software R&D Department, MS9915, PO Box 969, Livermore, CA 94550

Kolda, Tamara G.

211

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

212

Effect of Process Parameter on Barium Titanate Stannate (BTS) Materials Sintered at Low Sintering  

NASA Astrophysics Data System (ADS)

Ba(Ti1-xSnx)O3 solid solutions with (x = 0.15, 0.20, 0.30 and 0.40) are synthesized using conventional solid state reaction method. Formation of solid solutions in the range 0 ? x ?0.40 is confirmed using X-ray diffraction technique. Single phase solid solutions with homogeneous grain distribution are observed at relatively low sintering by controlling process parameters viz. sintering time. Composition at optimized temperature (1150 °C) sintered by varying the sintering time, stabilize in cubic perovskite phase. The % experimental density increase with increasing the time of sintering instead of increasing sintering temperature. The lattice parameter increases by increasing the tin composition in the material. This demonstrates that process parameter optimization can lead to single phase at relatively lower sintering-a major advantage for the materials used as capacitor element in MLCC.

Shukla, Alok; Bajpai, P. K.

2011-11-01

213

Orthogonal experiment and analysis on process parameters of bowl feed polishing (BFP)  

NASA Astrophysics Data System (ADS)

With the development of science and technology, the demand for high-precision product is increasing continuously. Ultra-smooth surface with sub-nanometer roughness has extensive applications in the field of soft X-ray optics, high power laser and laser gyro. Bowl feed polishing (BFP) technology is an effective ultra-smooth surface processing method, but the polishing process of BFP which is affected by a lot of factors is extremely complex and difficult to control. It is important to understand the effect of the process variables such as abrasive particle size, concentration of abrasive particle, speed of polishing pad, acidity and polishing time in the process of BFP. They are very important parameters that must be carefully formulated to achieve desired material removal rates and surface roughness. Using a design of experiment (DOE) approach, this study was performed investigating the main effect of the each parameter during K9 BFP. A better understanding of the interaction behavior between the various parameters and the effect on removal rate and surface roughness is achieved by using the statistical analysis techniques. In the experimental tests, the optimized parameters combination for BFP which were derived from the statistical analysis could be found for material removal rate and better surface roughness through the above experiment results.

Meng, Kai; Wan, Yongjian; Xu, Qinglan; Yang, Yang

2013-08-01

214

Liquid Antisolvent Recrystallization of Phenylbutazone and the Effect of Process Parameters  

Microsoft Academic Search

Phenylbutazone was crystallized from solutions by the liquid antisolvent recrystallization technique. Acetone was used as a solvent, and distilled water was selected as an antisolvent. The influence of processing parameters, such as drug concentration, temperature, injection rate of drug solution, and mixing method of drug solution with antisolvent, on the particle size distribution were investigated. Furthermore, to examine the variation

Su-Jin Park; Sang-Do Yeo

2011-01-01

215

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...

216

A neural network approach for selection of powder metallurgy materials and process parameters  

Microsoft Academic Search

The artificial neural network (NN) methodology presented in this paper has been developed for selection of powder and process parameters for Powder Metallurgy (PM) part manufacture. This methodology differs from the statistical modelling of mechanical properties in that it is not necessary to make assumptions regarding the form of the functions relating input and output variables. Employment of a NN

R. P. Cherian; L. N. Smith; P. S. Midha

2000-01-01

217

PROCESS PARAMETERS AND ENERGY USE OF GAS AND ELECTRIC OVENS IN INDUSTRIAL APPLICATIONS  

E-print Network

, thermoplastics and composites. The purpose of this study was to compare the process parameters under similar of Industrial Technologies to provide energy, waste, and productivity assessments, at no charge, to small and mid size manufacturers. During its 15 year history, the UMass IAC staff has performed plant

Massachusetts at Amherst, University of

218

Parameter Distributions for Speech Signals Modeled with Spherically-Invariant Random Processes  

E-print Network

for co-channel speech sep- aration and compare to a database of actual speech signals [5]. II. UsingParameter Distributions for Speech Signals Modeled with Spherically-Invariant Random Processes (SIRPs) have been used as a statistical model for speech and shown to better fit mea- sured probability

De Leon, Phillip

219

Optimal Selection of Sensors & Controller Parameters for Economic Optimization of Process Plants  

E-print Network

Optimal Selection of Sensors & Controller Parameters for Economic Optimization of Process Plants and nuc,dof = 0 (Existing) Design sensor networks using conven- tional methods such as maximizing precision, etc. If active constraints are perfectly controllable and nuc,dof > 0 (Obj. 1) Design sensor

Skogestad, Sigurd

220

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

221

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

222

Process Parameters Optimization for Energy Saving in Paper Machine Dryer Section  

Microsoft Academic Search

Due to high energy consumption in the Chinese paper industry, this study considers higher-energy efficiency for the multicylinder dryer section of paper machines. A common situation in the Chinese paper industry is that energy is consumed in extensive mode. In order to improve the energy efficiency of the paper machine dryer section, deeper analysis and optimization of process parameters are

Yugang Li; Huanbin Liu; Jigeng Li; Jinsong Tao

2011-01-01

223

Performance Assessment Method for a Forged Fingerprint Detection Algorithm  

NASA Astrophysics Data System (ADS)

The threat of invasion of privacy and of the illegal appropriation of information both increase with the expansion of the biometrics service environment to open systems. However, while certificates or smart cards can easily be cancelled and reissued if found to be missing, there is no way to recover the unique biometric information of an individual following a security breach. With the recognition that this threat factor may disrupt the large-scale civil service operations approaching implementation, such as electronic ID cards and e-Government systems, many agencies and vendors around the world continue to develop forged fingerprint detection technology, but no objective performance assessment method has, to date, been reported. Therefore, in this paper, we propose a methodology designed to evaluate the objective performance of the forged fingerprint detection technology that is currently attracting a great deal of attention.

Shin, Yong Nyuo; Jun, In-Kyung; Kim, Hyun; Shin, Woochang

224

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

225

Extension of the forming limits in cold and warm forging by the FE based fracture analysis with the integrated damage model of effective stresses  

Microsoft Academic Search

In this article the simulations of different cold and warm forging processes, based on the application of the finite element software MSC.SuperForm 2002, are presented with special emphasis on the occurrence of fracture in the ductile material failure of the ferrous materials used. The model of effective stresses (MES) was modified and integrated into the FE simulations of various manufacturing

A Behrens; H Just

2002-01-01

226

Determination of a suitable parameter field for the active fluid jet polishing process  

NASA Astrophysics Data System (ADS)

In 2012 a well-known company in the field of high precision optics assigned the University of Applied Sciences Deggendorf to determine a suitable parameter field for the active fluid jet polishing (AFJP) process in order to reach a surface accuracy of at least lambda / 5. The active fluid jet polishing is a relatively new and an affordable sub-aperture polishing process. For a fast and precise identification of the parameter field a considered design of experiment is necessary. The available control variables were the rotational speed of the nozzle, the distance between the test object and the jet, the feed rate, the material of the pin inside the nozzle and the material of the test object itself. In order to reach a significant data density on the one hand and to minimize the number of test runs on the other hand a meander shaped tool path was chosen. At each blank nine paths had been driven whereby at each path another parameter combination was picked. Thus with only one test object nine parameter settings may be evaluated. For the automatized analysis of the tracks a software tool was developed. The software evaluates ten sections which orthogonally intersect the nine tracks on the test-lens. The significant measurement parameters per section are the width and the height of each path as well as the surface roughness within the polished tracks. With the aid of these parameters and further statistical evaluations a suitable parameter field for the goal to find a constant and predictable removal spot was determined. Furthermore up to now over 60 test runs have been successfully finished with nine parameter combinations in each case. As a consequence a test evaluation by hand would be very time-consuming and the software facilitates it dramatically.

Maurer, Roland; Biskup, Heiko; Trum, Christian; Rascher, Rolf; Wünsche, Christine

2013-09-01

227

A New Friction and Lubrication Test for Cold Forging  

Microsoft Academic Search

This paper presents a new friction and lubrication test for cold forging. The test allows controlled variation of the surface expansion in the range 0-2000%, the tool temperature in the range 20-270°C and the sliding length between 0 and infinite. Friction is decreasing with increasing temperature in the range 30-150°C. Above this temperature range friction increases. As regards lubricant performance

N. Bay; O. Wibom; J. Aa. Nielsen

1995-01-01

228

Sinter-forging characteristics of fine-grained zirconia  

Microsoft Academic Search

Powder preforms of zirconia, containing 2.85 mol% yttria, were sinter-forged in simple uniaxial compression at 1400°C by applying constant displacement rates to the specimens. Shear and densification strains and the uniaxial stress were measured as a function of time. In contrast with alumina and silicon nitride, zirconia appears to densify by a dislocation mechanism. As a consequence, the densification rate

Prakash C. Panda; Jenqdaw Wang; Rishi Raj

1988-01-01

229

A determination of microbial parameters of a coconut processing pilot plant  

E-print Network

A DETERMINATION OF MICROBIAL PARAMETERS OF A COCONUT PROCESSING PILOT PLANT A Thesis by Theresa Marie Kajs Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER..., Im-G4) in the production process were held at 35 C for up to 8 hours 62 19 Changes in microbiological indices when certain intermediate products (Im-M(BC)4A, Im-M(AC)4A) in the production process were held at 35 C for up to 8 hours 63 20...

Kajs, Theresa Marie

1975-01-01

230

Influence of process parameters on tablet bed microenvironmental factors during pan coating.  

PubMed

Recent studies have shown the importance of monitoring microenvironmental conditions (temperature, relative humidity) experienced by the tablet bed during a pan coating process, thereby necessitating the need to understand how various process parameters influence these microenvironmental conditions. The process parameters studied in this work include exhaust air temperature, spray rate, inlet airflow rate, gun-to-bed distance, coating suspension percent solids, and atomization and pattern air pressure. Each of these process parameters was found to have an impact on the tablet bed relative humidity (RH), as measured using PyroButton data logging devices. A higher tablet bed RH was obtained with an increase in spray rate and atomization air pressure and with a decrease in exhaust air temperature, inlet airflow rate, gun-to-bed distance, suspension percent solids, and pattern air pressure. Based on this work, it can be concluded that the tablet bed thermodynamic conditions are a cumulative effect of the various process conditions. A strong correlation between the tablet bed RH and the frequency of tablet coating defect (logo bridging) was established, with increasing RH resulting in a higher percent of logo bridging events. PMID:24323824

Pandey, Preetanshu; Bindra, Dilbir S; Felton, Linda A

2014-04-01

231

The Effect of Process Parameters on the Microstructure and Mechanical Properties of Semisolid Cast Al6061  

NASA Astrophysics Data System (ADS)

An examination of the microstructure and mechanical properties of aluminum 6061 alloy samples produced by a miniature cooling slope is presented. The effects of several process parameters including pouring rate, cooling slope angle, superheat and cooling slope length on the microstructure and mechanical characteristics of the samples were investigated. An attempt was made to use the two-level factorial design method to determine the relationships between the process parameters and the properties of the semisolid aluminum 6061 alloy manufactured by the miniature cooling slope. Finally, an optimum processing region was identified. The interaction between the cooling slope length and the pouring rate (BC); the interaction among the superheat, the pouring rate, and the cooling slope length (ABC); and the cooling slope length (C), in the order mentioned, were identified as the most important effects.

Hajihashemi, Mahdi; Niroumand, Behzad; Shamanian, Morteza

2014-12-01

232

Forging And Milling Contribution On Residual Stresses For A Textured Biphasic Titanium Alloy  

SciTech Connect

Ti-10V-2Fe-3Al is a biphasic titanium alloy ({alpha}+{beta}) used in aeronautical applications for its mechanical properties, such as its yield strength of 1200 MPa and it weighs 40% less than steel. This alloy is particularly useful for vital parts with complex geometry, because of its high forging capability. In order to predict the capability for fatigue lifetime, the designers need to know the residual stresses. X-Ray diffraction is the main experimental technique used to determine residual stresses on the surface. In this case, stress levels are primarily influenced by the complex forging and milling process. On this alloy in particular, it may be difficult to characterize stress due to modification of the microstructure close to the surface. Results obtained by x-ray analysis depend on the correct definition of the shape of the diffraction peaks. The more precisely defined the position of the peak, the more accurately the stresses are evaluated. This paper presents a method to detect if residual stresses can be characterized by x-ray diffraction. The characterization of hardness seems to be a relevant technique to quickly analyze the capability of x-ray diffraction to determine residual stresses.

Deleuze, C. [Arts et Metiers ParisTech, MecaSurf, 2, Cours des Arts et Metiers, 13617 Aix en Provence (France); Eurocopter, EQTTL, Aeroport International Marseille France, 13725 Marignane Cedex (France); Fabre, A.; Barrallier, L. [Arts et Metiers ParisTech, MecaSurf, 2, Cours des Arts et Metiers, 13617 Aix en Provence (France); Molinas, O. [Eurocopter, EQTTL, Aeroport International Marseille France, 13725 Marignane Cedex (France)

2011-01-17

233

Forging tool shape optimization using pseudo inverse approach and adaptive incremental approach  

NASA Astrophysics Data System (ADS)

This paper presents a simplified finite element method called "Pseudo Inverse Approach" (PIA) for tool shape design and optimization in multi-step cold forging processes. The approach is based on the knowledge of the final part shape. Some intermediate configurations are introduced and corrected by using a free surface method to consider the deformation paths without contact treatment. A robust direct algorithm of plasticity is implemented by using the equivalent stress notion and tensile curve. Numerical tests have shown that the PIA is very fast compared to the incremental approach. The PIA is used in an optimization procedure to automatically design the shapes of the preform tools. Our objective is to find the optimal preforms which minimize the equivalent plastic strain and punch force. The preform shapes are defined by B-Spline curves. A simulated annealing algorithm is adopted for the optimization procedure. The forging results obtained by the PIA are compared to those obtained by the incremental approach to show the efficiency and accuracy of the PIA.

Halouani, A.; Meng, F. J.; Li, Y. M.; Labergère, C.; Abbès, B.; Lafon, P.; Guo, Y. Q.

2013-05-01

234

Forging And Milling Contribution On Residual Stresses For A Textured Biphasic Titanium Alloy  

NASA Astrophysics Data System (ADS)

Ti-10V-2Fe-3Al is a biphasic titanium alloy (?+?) used in aeronautical applications for its mechanical properties, such as its yield strength of 1200 MPa and it weighs 40% less than steel. This alloy is particularly useful for vital parts with complex geometry, because of its high forging capability. In order to predict the capability for fatigue lifetime, the designers need to know the residual stresses. X-Ray diffraction is the main experimental technique used to determine residual stresses on the surface. In this case, stress levels are primarily influenced by the complex forging and milling process. On this alloy in particular, it may be difficult to characterize stress due to modification of the microstructure close to the surface. Results obtained by x-ray analysis depend on the correct definition of the shape of the diffraction peaks. The more precisely defined the position of the peak, the more accurately the stresses are evaluated. This paper presents a method to detect if residual stresses can be characterized by x-ray diffraction. The characterization of hardness seems to be a relevant technique to quickly analyze the capability of x-ray diffraction to determine residual stresses.

Deleuze, C.; Fabre, A.; Barrallier, L.; Molinas, O.

2011-01-01

235

A new method for determination of parameters in sewer pollutant transformation process model.  

PubMed

Understanding pollutant transformation in sewers is important in controlling odor emission from pressure mains as well as in assessing organic pollutant removal capacity of gravity sewers. Sewer process models have thus been developed to quantify the pollutant transformation processes under various sewer conditions. The quantification largely depends on model parameter values, in particular the kinetic and stoichiometric parameters related to microbial activities. The current approaches not only involve a large amount of experimental work but also may induce significant errors when microbial reactions cannot be differentiated effectively during the experiments. Therefore, this study is aimed at developing a new method that can reduce experimental work significantly. The proposed method utilizes a genetic algorithm (GA) to enable the determination with a single set of batch experiments. To study the feasibility of the proposed method, a set of 72-hr batch experiments was first conducted for determining the parameters of a sewer model developed in this study, which adopted a full version of the International Water Association (IWA) Activated Sludge Model No. 3 (ASM3) to describe the microbial activities in sewers. The results were then verified with two different sets of the batch experiments. Furthermore, dynamic variation data of dissolved oxygen level were collected at the outlet of a 1.5-km gravity sewer to validate the determined parameters. All the results showed that the proposed parameter determination method is effective. PMID:18290531

Jiang, F; Leung, H W D; Li, S Y; Lin, G S; Chen, G H

2007-11-01

236

Laser Trimming of CuAlMo Thin-Film Resistors: Effect of Laser Processing Parameters  

NASA Astrophysics Data System (ADS)

This paper reports the effect of varying laser trimming process parameters on the electrical performance of a novel CuAlMo thin-film resistor material. The films were prepared on Al2O3 substrates by direct-current (DC) magnetron sputtering, before being laser trimmed to target resistance value. The effect of varying key laser parameters of power, Q-rate, and bite size on the resistor stability and tolerance accuracy were systematically investigated. By reducing laser power and bite size and balancing this with Q-rate setting, significant improvements in resistor stability and resistor tolerance accuracies of less than ±0.5% were achieved.

Birkett, Martin; Penlington, Roger

2012-08-01

237

Estimation of Temperature Dependent Parameters of a Batch Alcoholic Fermentation Process  

NASA Astrophysics Data System (ADS)

In this work, a procedure was established to develop a mathematical model considering the effect of temperature on reaction kinetics. Experiments were performed in batch mode in temperatures from 30 to 38°C. The microorganism used was Saccharomyces cerevisiae and the culture media, sugarcane molasses. The objective is to assess the difficulty in updating the kinetic parameters when there are changes in fermentation conditions. We conclude that, although the re-estimation is a time-consuming task, it is possible to accurately describe the process when there are changes in raw material composition if a re-estimation of parameters is performed.

de Andrade, Rafael Ramos; Rivera, Elmer Ccopa; Costa, Aline C.; Atala, Daniel I. P.; Filho, Francisco Maugeri; Filho, Rubens Maciel

238

Workability in forging of powder metallurgy compacts  

Microsoft Academic Search

The power metallurgy (PM) technique is now applied widely to many industries and materials. To obtain more reliable PM products, many secondary processes are applied to PM preforms. The problem of deformation and fracture of PM preforms still needs a considerable amount of investigation.In this work, the effect of the relative density on the forming limit of PM compacts in

M. Abdel-Rahman; M. N. El-Sheikh

1995-01-01

239

Evaluation of critical process parameters for intra-tablet coating uniformity using terahertz pulsed imaging.  

PubMed

The purpose of this study was to evaluate the intra-tablet coating uniformity and the identification of critical process parameters in an active pan coating process using terahertz pulsed imaging (TPI). A design of experiments (DoE) was performed with drum load, drum speed, spray rate, run duration and spray pressure as factors. Different measures of intra-tablet uniformity were investigated: the average thickness on the individual tablet faces, spatial variation in layer thickness over the tablet surface, and the coefficient of variation (CV(intra)). Data analysis revealed that the process parameters in the investigated parameter space had hardly any influence on the difference in layer thickness of the tablet faces and centre band. No increase or decrease in layer thickness--as described in the literature--was found towards the edges of the tablet face. In overwetted process conditions a higher layer thickness at the centre band edges could be observed. Still, the highest variability in coating thickness was found along the circumference of the centre band rather than the height. In general, higher CV(intra) of layer thickness were found on the centre bands in comparison with the tablet faces. The analysis of the DoE model revealed that the run duration had the highest influence on the CV(intra) on the tablet faces. TPI showed high potential in the assessment of intra-tablet uniformity and layer thickness distributions over the whole tablet surface. It was successfully used to identify critical process parameters regarding intra-tablet coating uniformity. PMID:23872179

Brock, Daniela; Zeitler, J Axel; Funke, Adrian; Knop, Klaus; Kleinebudde, Peter

2013-11-01

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

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

242

A preliminary evaluation of an F100 engine parameter estimation process using flight data  

NASA Technical Reports Server (NTRS)

The parameter estimation algorithm developed for the F100 engine is described. The algorithm is a two-step process. The first step consists of a Kalman filter estimation of five deterioration parameters, which model the off-nominal behavior of the engine during flight. The second step is based on a simplified steady-state model of the compact engine model (CEM). In this step, the control vector in the CEM is augmented by the deterioration parameters estimated in the first step. The results of an evaluation made using flight data from the F-15 aircraft are presented, indicating that the algorithm can provide reasonable estimates of engine variables for an advanced propulsion control law development.

Maine, Trindel A.; Gilyard, Glenn B.; Lambert, Heather H.

1990-01-01

243

Impact of Baryonic Processes on Weak Lensing Cosmology: Higher-Order Statistics and Parameter Bias  

E-print Network

We study the impact of baryonic physics on cosmological parameter estimation with weak lensing surveys. We run a set of cosmological hydrodynamics simulations with different galaxy formation models. We then perform ray-tracing simulations through the total matter density field to generate 100 independent convergence maps of 25 deg$^2$ field-of-view, and use them to examine the ability of the following three lensing statistics as cosmological probes; power spectrum, peak counts, and Minkowski Functionals. For the upcoming wide-field observations such as Subaru Hyper Suprime-Cam (HSC) survey with a sky coverage of 1400 deg$^2$, the higher-order statistics provide tight constraints on the matter density, density fluctuation amplitude, and dark energy equation of state, but appreciable parameter bias is induced by the baryonic processes such as gas cooling and stellar feedback. When we use power spectrum, peak counts, and Minkowski Functionals, the relative bias in the dark energy equation of state parameter $w$ ...

Osato, Ken; Yoshida, Naoki

2015-01-01

244

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

245

Mechanical properties and microstructure of Al-Li-Cu-Mg-Zr die forgings  

NASA Astrophysics Data System (ADS)

Four forgings of Al 8090 alloy were evaluated for strength, toughness, and stress corrosion resistance. A microstructural evaluation was also conducted. The forgings easily met the strength requirements for Al 7075-T73 but only just met the 7 pct minimum elongation requirement. The stress corrosion threshold was less than 35 MPa in the short transverse orientation, a value that is far below the 310 MPa minimum often required for Al 7075-T73. Fracture in areas which received low forging reductions was intergranular, while fracture in more heavily forged areas was also along subgrain boundaries. Possible mechanisms for the low toughness and stress corrosion resistance of Al-Li alloys are discussed.

Webster, Donald; Kirkbride, Richard

1986-11-01

246

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

247

The sensitivity of energy requirements to process parameters for CuInSe2 module production  

Microsoft Academic Search

The energy input requirements for thin-film PV (photovoltaic) modules are discussed, using CuInSe2-based cells as an example. Energy payback times and energy ratios are calculated over a range of insolation levels for various semiconductor deposition techniques. The sensitivity of the energy requirements to single and double process parameter variations for the stacked elemental layer technique is also investigated

K. M. Hynes; N. M. Pearsall; R. Hill

1991-01-01

248

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

249

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

250

Hydraulic parameters in eroding rills and their influence on detachment processes  

NASA Astrophysics Data System (ADS)

In many experiments as well in laboratory as in field experiments the correlations between the detachment rate and different hydraulic parameters are calculated. The used parameters are water depth, runoff, shear stress, unit length shear force, stream power, Reynolds- and Froude number. The investigations show even contradictory results. In most soil erosion models like the WEPP model, the shear stress is used to predict soil detachment rates. But in none of the WEPP datasets, the shear stress showed the best correlation to the detachment rate. In this poster we present the results of several rill experiments in Andalusia from 2008 and 2009. With the used method, it is possible to measure the needed factors to calculate the mentioned parameters. Water depth is measured by an ultrasonic sensor, the runoff values are calculated by combining flow velocity and flow diameter. The parameters wetted perimeter, flow diameter and hydraulic radius can be calculated from the measured rill cross sections and the measured water levels. In the sample density values, needed for calculation of shear stress, unit length shear force and stream power, the sediment concentration and the grain density are are considered. The viscosity of the samples was measured with a rheometer. The result of this measurements shows, that there is a very high linear correlation (R² = 0.92) between sediment concentration and the dynamic viscosity. The viscosity seems to be an important factor but it is only used in the Reynolds-number-equation, in other equations it is neglected. But the viscosity value increases with increasing sediment concentration and hence the influence also increases and the in multiclications negiligible viscosity value of 1 only counts for clear water. The correlations between shear stress, unit length shear force and stream power at the x-axis and the detachment rate at the ordinate show, that there is not one fixed parameter that always displays the best correlation to the detachment rate. The best hit does not change from one experiment to another, it changes from one measuring point to another. Different processes in rill erosion are responsible for the changing correlations. In some cases no one of the parameters shows an acceptable correlation to the soil detachment, because these factors describe fluvial processes. Our experiments show, that not the fluvial processes cause the main sediment procduction in the rills, but bank failure or knickpoint and headcut retreat and these processes are more gravitative than fluvial. Another sediment producing process is the abrupt spill over of plunge pools, a process not realy fluvial and not realy gravitativ. In some experiments, the highest sediment concentrations were measured at the slowly flowing waterfront that only transports the loose material. But all these processes are not considered in soil erosion models. Hence, hydraulic parameters alone are not sufficient to predict detachment rates. They cover the fluvial incising in the rill's bottom, but the main sediment sources are not considered satisying in its equations.

Wirtz, Stefan; Seeger, Manuel; Zell, Andreas; Wagner, Christian; Wengel, René; Ries, Johannes B.

2010-05-01

251

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

252

Polyoxylglycerides and glycerides: effects of manufacturing parameters on API stability, excipient functionality and processing.  

PubMed

Lipid-based formulations are a viable option to address modern drug delivery challenges such as increasing the oral bioavailability of poorly water-soluble active pharmaceutical ingredients (APIs), or sustaining the drug release of molecules intended for chronic diseases. Esters of fatty acids and glycerol (glycerides) and polyethylene-glycols (polyoxylglycerides) are two main classes of lipid-based excipients used by oral, dermal, rectal, vaginal or parenteral routes. These lipid-based materials are more and more commonly used in pharmaceutical drug products but there is still a lack of understanding of how the manufacturing processes, processing aids, or additives can impact the chemical stability of APIs within the drug product. In that regard, this review summarizes the key parameters to look at when formulating with lipid-based excipients in order to anticipate a possible impact on drug stability or variation of excipient functionality. The introduction presents the chemistry of natural lipids, fatty acids and their properties in relation to the extraction and refinement processes. Then, the key parameters during the manufacturing process influencing the quality of lipid-based excipients are provided. Finally, their critical characteristics are discussed in relation with their intended functionality and ability to interact with APIs and others excipients within the formulation. PMID:24607211

Jannin, Vincent; Rodier, Jean-David; Musakhanian, Jasmine

2014-05-15

253

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.

2002-01-01

254

Production of furfural from pentosan-rich biomass: analysis of process parameters during simultaneous furfural stripping.  

PubMed

Among the furan-based compounds, furfural (FUR) shows interesting properties as building-block or industrial solvent. It is produced from pentosan-rich biomass via xylose cyclodehydration. The current FUR production makes use of homogeneous catalysts and excessive amounts of steam. The development of greener furfural production and separation techniques implies the use of heterogeneous catalysts and innovative separation processes. This work deals with the conversion of corncobs as xylose source to be dehydrated to furfural. The results reveal differences between the use of direct corncob hydrolysis and dehydration to furfural and the prehydrolysis and dehydration procedures. Moreover, this work focuses on an economical analysis of the main process parameters during N2-stripping and its economical comparison to the current steam-stripping process. The results show a considerable reduction of the annual utility costs due to use of recyclable nitrogen and the reduction of the furfural purification stages. PMID:23810948

Agirrezabal-Telleria, I; Gandarias, I; Arias, P L

2013-09-01

255

Plasma parameter analysis of the Langmuir decay process via Particle-in-Cell simulations  

NASA Astrophysics Data System (ADS)

The beam-plasma mechanism, based on the Langmuir decay process, has been proposed to explain naturally enhanced ion-acoustic lines (NEIALs), which are spectral distortions in incoherent scatter radar (ISR) data frequently observed in the vicinity of auroral arcs. In this work the effect of the Langmuir decay process on the ISR spectrum is studied and compared with an analytical model for different plasma parameters by using an electrostatic parallel particle-in-cell (EPPIC) code. Simulations show that the code is working in accordance with theory for a wide range of beam and plasma values and that the features of the spectrum are sensitive to changes of those values. These results suggest that the EPPIC code might be used to build a spectrum-plasma parameter model which will allow estimation of beam and plasma parameters from observed spectra. Simulations also confirm that background electron density (ne) plays an important role in determining the maximum detectable wavenumber of the enhancement. Specifically, results demonstrate that an increase in ne makes the enhancements of the ion acoustic more likely line at large wavenumbers, a finding consistent with statistical studies showing more frequent NEIAL occurrence near solar maximum. Finally, the simulations expose some inaccuracies of the current theoretical model in quantifying the energy passed from the beam to the Langmuir waves as well as with the range of enhanced wavenumbers. These differences may be attributable to the weak Langmuir turbulent regime assumption used in the theory.

Diaz, M. A.; Zettergren, M.; Semeter, J. L.; Oppenheim, M.

2012-08-01

256

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

257

A Graphics Processing Unit-enabled, High-resolution Cosmological Microlensing Parameter Survey  

NASA Astrophysics Data System (ADS)

In the era of synoptic surveys, the number of known gravitationally lensed quasars is set to increase by over an order of magnitude. These new discoveries will enable a move from single-quasar studies to investigations of statistical samples, presenting new opportunities to test theoretical models for the structure of quasar accretion disks and broad emission line regions (BELRs). As one crucial step in preparing for this influx of new lensed systems, a large-scale exploration of microlensing convergence-shear parameter space is warranted, requiring the computation of O(105) high-resolution magnification maps. Based on properties of known lensed quasars, and expectations from accretion disk/BELR modeling, we identify regions of convergence-shear parameter space, map sizes, smooth matter fractions, and pixel resolutions that should be covered. We describe how the computationally time-consuming task of producing ~290,000 magnification maps with sufficient resolution (10,0002 pixel map-1) to probe scales from the inner edge of the accretion disk to the BELR can be achieved in ~400 days on a 100 teraflop s-1 high-performance computing facility, where the processing performance is achieved with graphics processing units. We illustrate a use-case for the parameter survey by investigating the effects of varying the lens macro-model on accretion disk constraints in the lensed quasar Q2237+0305. We find that although all constraints are consistent within their current error bars, models with more densely packed microlenses tend to predict shallower accretion disk radial temperature profiles. With a large parameter survey such as the one described here, such systematics on microlensing measurements could be fully explored. ), an international collaboration supported by the Australian Research Council.

Bate, N. F.; Fluke, C. J.

2012-01-01

258

A GRAPHICS PROCESSING UNIT-ENABLED, HIGH-RESOLUTION COSMOLOGICAL MICROLENSING PARAMETER SURVEY  

SciTech Connect

In the era of synoptic surveys, the number of known gravitationally lensed quasars is set to increase by over an order of magnitude. These new discoveries will enable a move from single-quasar studies to investigations of statistical samples, presenting new opportunities to test theoretical models for the structure of quasar accretion disks and broad emission line regions (BELRs). As one crucial step in preparing for this influx of new lensed systems, a large-scale exploration of microlensing convergence-shear parameter space is warranted, requiring the computation of O(10{sup 5}) high-resolution magnification maps. Based on properties of known lensed quasars, and expectations from accretion disk/BELR modeling, we identify regions of convergence-shear parameter space, map sizes, smooth matter fractions, and pixel resolutions that should be covered. We describe how the computationally time-consuming task of producing {approx}290,000 magnification maps with sufficient resolution (10,000{sup 2} pixel map{sup -1}) to probe scales from the inner edge of the accretion disk to the BELR can be achieved in {approx}400 days on a 100 teraflop s{sup -1} high-performance computing facility, where the processing performance is achieved with graphics processing units. We illustrate a use-case for the parameter survey by investigating the effects of varying the lens macro-model on accretion disk constraints in the lensed quasar Q2237+0305. We find that although all constraints are consistent within their current error bars, models with more densely packed microlenses tend to predict shallower accretion disk radial temperature profiles. With a large parameter survey such as the one described here, such systematics on microlensing measurements could be fully explored.

Bate, N. F.; Fluke, C. J., E-mail: cfluke@swin.edu.au [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122 (Australia)

2012-01-10

259

Role of processing parameters on morphology, resistance and composition of laser fired contacts  

NASA Astrophysics Data System (ADS)

Laser processing is a single step, attractive alternative to current multi-step formation of ohmic contacts between an aluminum metallization layer and a silicon substrate in solar cell devices. However, small changes in laser parameters such as pulse duration, power density and laser wavelength can result in significant differences in the contact geometry and electrical properties. Here, the effects of power density and pulse duration on the morphology, resistance and surface concentration of laser fired contacts (LFCs) are examined experimentally. The minimum fluence threshold for forming a contact with measureable resistance through the 100nm SiO2 layer is determined to be 8 J/cm2. In addition, when forming the contact, an outer rim region accumulates on the surface that is comprised of aluminum and silicon. As a result, the entire contact is actually governed by the size of an inner crater region plus this outer rim material, which is in contrast to results reported in the literature for nanosecond pulse durations. These results are in good agreement with independent results reported in the literature for LFCs processed on wafers with substantially different base resistivity and using significantly different processing parameters.

Raghavan, A.; Palmer, T. A.; Domask, A.; Mohney, S.; Reutzel, E. W.; DebRoy, T.

2013-09-01

260

Characterization of wet granulation process parameters using response surface methodology. 1. Top-spray fluidized bed.  

PubMed

Randomized full-factorial designs (3(2)) were used to investigate the effects of processing conditions in the top-spray fluidized bed (TSFB) on the granulation of acetaminophen powder (USP) using 5% polyvinylpyrrolidone (w/w) as the binder. Measured granule properties included the following: mean size and size distribution, specific surface area, bulk density, tapped density, flow rate through an orifice, angle of repose, residual moisture content, and percent overs (> 2 mm). The granules were then compressed (500, 1000, 1500 lbs) into tablets (9-mm shallow concave) using an instrumented rotary press and analyzed for both physical properties and drug-release characteristics. All experimental batches were run in triplicate to reduce the possibility of erroneous results and to increase the confidence in the resulting empirical relationships derived using response-surface methodology. Measured responses were then related to process parameters using two-factor and three-factor linear, interactions, and quadratic regression models. These models were used to generate three-dimensional response surfaces for use in the final analyses. Coefficients of determination (R2) ranging from 0.08 to 0.81 were obtained, indicating that only a portion of the variation in the data could be explained by the changes in process parameter settings during granulation and tableting. The best overall model fits were observed for mean granule size, size distribution, bulk density, tapped density, percent drug dissolution, tablet disintegration time, and tablet friability. PMID:7965672

Lipps, D M; Sakr, A M

1994-07-01

261

Beer fermentation: monitoring of process parameters by FT-NIR and multivariate data analysis.  

PubMed

This work investigates the capability of Fourier-Transform near infrared (FT-NIR) spectroscopy to monitor and assess process parameters in beer fermentation at different operative conditions. For this purpose, the fermentation of wort with two different yeast strains and at different temperatures was monitored for nine days by FT-NIR. To correlate the collected spectra with °Brix, pH and biomass, different multivariate data methodologies were applied. Principal component analysis (PCA), partial least squares (PLS) and locally weighted regression (LWR) were used to assess the relationship between FT-NIR spectra and the abovementioned process parameters that define the beer fermentation. The accuracy and robustness of the obtained results clearly show the suitability of FT-NIR spectroscopy, combined with multivariate data analysis, to be used as a quality control tool in the beer fermentation process. FT-NIR spectroscopy, when combined with LWR, demonstrates to be a perfectly suitable quantitative method to be implemented in the production of beer. PMID:24594186

Grassi, Silvia; Amigo, José Manuel; Lyndgaard, Christian Bøge; Foschino, Roberto; Casiraghi, Ernestina

2014-07-15

262

76 FR 24856 - Heavy Forged Hand Tools (i.e., Axes & Adzes, Bars & Wedges, Hammers & Sledges, and Picks...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-803] Heavy Forged Hand Tools (i.e., Axes & Adzes, Bars & Wedges, Hammers...review of the antidumping duty orders on heavy forged hand tools (``Hand Tools'') (i.e., Axes & Adzes, Bars &...

2011-05-03

263

The influence of generator actuation mode and process parameters on the performance of finish EDM of a tool steel  

Microsoft Academic Search

The AISI P20 steel is applied by the tooling industry as material for injection molding. It is known that the EDM process parameters technology installed at the majority of CNC EDM machines do not cover some of the necessities of the tooling industry concerning process parameters for a wide range of workpiece materials. Considering this situation, the customers are required

F. L. Amorim; W. L. Weingaertner

2005-01-01

264

Vibration control in forge hammers. [by shock wave damping in foundation platform  

NASA Technical Reports Server (NTRS)

Special measures are discussed for calculating, designing and executing a forge hammer foundation, so that the vibrations that occur during its working will not be transmitted to neighboring machinery, workrooms and offices. These vibrations are harmful to the workers near the forge hammer.

Moise, F.; Lazarescu, C.

1974-01-01

265

DECOMPOSITION OF FORGING DIES FOR MACHINING PLANNING Laurent TAPIE, Bernardin Kwamivi MAWUSSI, Bernard ANSELMETTI  

E-print Network

planning in the case of high speed machining finishing operations. This method lies on a machining featureDECOMPOSITION OF FORGING DIES FOR MACHINING PLANNING Laurent TAPIE, Bernardin Kwamivi MAWUSSI, Bernard ANSELMETTI Abstract: This paper will provide a method to decompose forging dies for machining

Boyer, Edmond

266

A critical evaluation of the double cup extrusion test for selection of cold forging lubricants  

Microsoft Academic Search

The performance evaluation of cold forging lubricants and coatings as well as determination of the friction coefficients is necessary for production as well as finite element (FE) simulations. The double cup extrusion test (DCET) has been widely used to evaluate cold forging lubricants, since it was believed to accurately emulate the practical conditions (severity of deformation and surface expansion) found

Timothy Schrader; Manas Shirgaokar; Taylan Altan

2007-01-01

267

Experimental and analytical evaluation for elastic deformation behaviors of cold forging tool  

Microsoft Academic Search

Since the dimensional accuracy of forged parts are largely influenced by elastic behaviors of the tool material. The characteristics of elastic deformation at a forming tool are evaluated for a cold forged alloyed steel by experiment and FEM analysis.Elastic strain at the tool is measured dynamically using strain gauges attached to the surface of die for a ball stud mass-produced

Young-Seon Lee; Jung-Hwan Lee; Jong-Ung Choi; T Ishikawa

2002-01-01

268

The influence of lubrication on the surface finish of cold forged components  

Microsoft Academic Search

To establish the influence of lubrication on the surface finish of cold forged components a series of workpieces made of copper, aluminium and heading steel were forged within hexagonal and square shaped dies. Tests were performed under non-lubricated, or “Dry”, and lubricated conditions. It was found that the surface finish was influenced by both the lubrication conditions and the particular

J. Monaghan; M. O'Reilly

1996-01-01

269

Analysis of the friction and wear behaviour of hot work tool steel for forging  

Microsoft Academic Search

A significant part of the energy in forging is used to break the interfacial junctions due to friction between the tool and the workpiece. The life of hot-forging tools is usually limited by complex interactive mechanisms under cyclic loading such as abrasive, adhesive and scaling wear, thermal and mechanical fatigue, and plastic deformation.This contribution deals with the wear mechanisms of

O Barrau; C Boher; R Gras; F Rezai-Aria

2003-01-01

270

FEM simulation for cold press forging forming of the round-fin heat sink  

NASA Astrophysics Data System (ADS)

In this paper, the finite element method is used to investigate the forming process of cold press forging for the round-fin heat sink in the automotive lighting. A series of simulations on the round-fin heat sink forming using the program DEFORM were carried out. The blank thickness and friction coefficient on the formation of round-fin were studied, and the tooling structure with counterpressure on the heat sink formation was also investigated. The results show that the blank thickness is very good for the round-fin formation, and the thicker the blank is, the better the round-fin can be formed; and also When both the punch-blank interface and the die-blank interface have the same value of friction factor, the larger value of friction factor is in favor of round-fin forming, the further investigation reveals that the friction at the punch-blank interface has more significant effect on preventing the initiation of flow-through compared with the friction at the die-blank interface, which implies that the punch-blank interface has more significant effect on the material flow in the formation of round-fin. Meanwhile, The tooling structure with counterpressure is helpful to the formation of round-fin heat sink, which not only ensures the height of each round-fin on the heat sink is uniform but also retards the initiation of flow-through on the reverse side of round-fin. In addition, the experiments of press forging process were conducted to validate the finite element analysis, and the simulation results are in good agreement with the experimental data.

Wang, Kesheng; Han, Yu; Zhang, Haiyan; Zhang, Lihan

2013-05-01

271

Anisotropie embrittlement in high-hardness ESR 4340 steel forgings  

NASA Astrophysics Data System (ADS)

ESR 4340 steel forgings tempered to a hardness of HRC 55 exhibit a severe loss of tensile ductility in the short transverse direction which is strain-rate and humidity dependent. The anisotropy is also reflected in blunt-notch Charpy impact energy, but is absent in the sharp-crack fracture toughness. Brittle behavior is associated with regions of smooth intergranular fracture which are aligned with microstructural banding. Scanning Auger microprobe analysis indicates some intergranular segregation of phosphorus and sulfur in these regions. The anisotropic embrittlement is attributed to an interaction of nonequilibrium segregation on solidification with local equilibrium segregation at grain boundaries during austenitizing. This produces defective regions of enhanced intergranular impurity segregation which are oriented during forging. The regions are prone to brittle fracture under impact conditions and abnormal sensitivity to environmental attack during low strain-rate deformation. A relatively sparse distribution of these defects (˜10cm-3) accounts for the discrepancy between smooth bar and blunt-notch tests vs sharp-crack tests. Isotropie properties are restored by homogenization treatment. For application of these steels at extreme hardness levels, homogenization treatment is essential.

Olson, G. B.; Anctil, A. A.; Desisto, T. S.; Kula, E. B.

1983-08-01

272

Development of forging technology for PWR primary piping  

SciTech Connect

The purpose of this presentation is to give information on the changes in the design and manufacture of Primary Piping for electronuclear boilers of the Pressurized Water Reactor type (PWR) which has resulted in the making of one-piece forged lines including stub pipes and arcs. The optimization of these items is aimed at improving the life of the new power stations as well as guaranteeing their safety, while reducing inspection and maintenance requirements in service. The demonstration of the manufacturing feasibility has just been completed. It has taken material form in the installation, on the CIVAUX 1 section, of the first one-piece cold leg in the world. It will shortly be followed by the installation on the CIVAUX 2 section of a complete loop of bent forged pipes. Therefore, this new know-how is going to be incorporated in the French Rules (RCC-M) and can be directly taken into consideration both in the next work to be done and in the design and definition of a future nuclear reactor.

Morin, F. [Electricite de France, Evry (France); Badeau, J.P. [Creusot Loire Industrie, Le Creusot (France); Lambs, R. [Framatome, La Defense (France)

1996-12-01

273

Evaluation of the influence of granulation processing parameters on the granule properties and dissolution characteristics of a modified release drug  

Microsoft Academic Search

Understanding the relationship between high shear wet granulation processing parameters and the characteristics of intermediate and final products is crucial in the ability to apply quality by design (QbD) and process analytical technologies (PAT) to secondary pharmaceutical processes. This research examined a high shear wet granulation process and subsequent manufacturing of a tablet containing a biopharmaceutics classification system (BCS) class

D. T. Ring; J. C. O. Oliveira; A. Crean

2011-01-01

274

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

275

Employment of the covariance matrix in parameter estimation for stochastic processes in cell biology  

NASA Astrophysics Data System (ADS)

The dynamics of movements of biological cells can be described with models from correlated stochastic processes. In order to overcome problems from correlated and insufficient data in the determination of the model parameters of such processes we employ the covariance matrix of the data. Since the covariance suffers itself from statistical uncertainty it is corrected by a renormalization treatment [1]. For the example of normal and fractional Brownian motion, which allows both to access all quantities on full theoretical grounds and to generate data similar to experiment, we discuss our results and those of previous works by Gregory [2] and Sivia [3]. The presented approach has the potential to estimate the aging correlation function of observed cell paths and can be applied to more complicated models.

Preuss, R.; Dieterich, P.

2013-08-01

276

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

277

Metallurgical processing and pulsed reactor fuel performance  

Microsoft Academic Search

Metallurgical methods for improving fuel performance were studied. It was concluded that fatigue failure is responsible for fuel fractures and that changes in fuel processing are the most practical means of achieving improvement. A hot forging step was chosen for investigation. Four prototype fuel plates of depleted U-10Mo alloy were produced, two by conventional casting and two by upset forging

J. P. Hickerson Jr.; J. P. Jr

1974-01-01

278

Neuropsychological parameters indexing executive processes are associated with independent components of ERPs.  

PubMed

Lesion studies have indicated that at least the three executive processes can be differentiated in the frontal lobe: Energization, monitoring and task setting. Event related potentials (ERPs) in Go/NoGo tasks have been widely used in studying executive processes. In this study, ERPs were obtained from EEG recorded during performance of a cued Go/NoGo task. The Contingent Negative Variation (CNV) and P3NoGo waves were decomposed into four independent components (ICs), by applying Independent Component Analysis (ICA) to a collection of ERPs from 193 healthy individuals. The components were named IC CNVearly, IC CNVlate, IC P3NoGoearly and IC P3NoGolate according to the conditions and time interval in which they occurred. A sub-group of 28 individuals was also assessed with neuropsychological tests. The test parameters were selected on the basis of studies demonstrating their sensitivity to executive processes as defined in the ROtman-Baycrest Battery for Investigating Attention (ROBBIA) model. The test scores were categorized into the domain scores of energization, monitoring and task setting and correlated with the amplitudes of the individual ICs from the sub-group of 28 individuals. The energization domain correlated with the IC CNVlate and IC P3NoGoearly. The monitoring domain correlated with the IC P3NoGolate, while the task setting domain correlated with the IC CNVlate. The IC CNVearly was not correlated with any of the neuropsychological domain scores. The correlations between the domains and ICs remained largely unchanged when controlling for full-scale IQ. This is the first study to demonstrate that executive processes, as indexed by neuropsychological test parameters, are associated with particular event-related potentials in a cued Go/NoGo paradigm. PMID:25448863

Brunner, Jan Ferenc; Olsen, Alexander; Aasen, Ida Emilia; Løhaugen, Gro C; Håberg, Asta K; Kropotov, Juri

2015-01-01

279

Impact of processing parameters on the haemocompatibility of Bombyx mori silk films  

PubMed Central

Silk has traditionally been used for surgical sutures due to its lasting strength and durability; however, the use of purified silk proteins as a scaffold material for vascular tissue engineering goes beyond traditional use and requires application-orientated biocompatibility testing. For this study, a library of Bombyx mori silk films was generated and exposed to various solvents and treatment conditions to reflect current silk processing techniques. The films, along with clinically relevant reference materials, were exposed to human whole blood to determine silk blood compatibility. All substrates showed an initial inflammatory response comparable to polylactide-co-glycolide (PLGA), and a low to moderate haemostasis response similar to polytetrafluoroethylene (PTFE) substrates. In particular, samples that were water annealed at 25 °C for 6 h demonstrated the best blood compatibility based on haemostasis parameters (e.g. platelet decay, thrombin-antithrombin complex, platelet factor 4, granulocytes-platelet conjugates) and inflammatory parameters (e.g. C3b, C5a, CD11b, surface-associated leukocytes). Multiple factors such as treatment temperature and solvent influenced the biological response, though no single physical parameter such as ?-sheet content, isoelectric point or contact angle accurately predicted blood compatibility. These findings, when combined with prior in vivo data on silk, support a viable future for silk-based vascular grafts. PMID:22079005

Seib, F. Philipp; Maitz, Manfred F.; Hu, Xiao; Werner, Carsten; Kaplan, David L.

2013-01-01

280

77 FR 39997 - Heavy Forged Hand Tools, Finished or Unfinished, With or Without Handles From the People's...  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-570-803] Heavy Forged Hand Tools, Finished or Unfinished, With or...antidumping duty review on heavy forged hand tools, finished or unfinished, with or...United States). \\2\\ See Heavy Forged Hand Tools, Finished or Unfinished, With...

2012-07-06

281

76 FR 31631 - Heavy Forged Hand Tools From China; Scheduling of Expedited Five-Year Reviews Concerning the...  

Federal Register 2010, 2011, 2012, 2013

...731-TA-457-A-D Third Review] Heavy Forged Hand Tools From China; Scheduling of Expedited...Antidumping Duty Orders on Heavy Forged Hand Tools From China. AGENCY: United States...antidumping duty orders on heavy forged hand tools from China would be likely to...

2011-06-01

282

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

Federal Register 2010, 2011, 2012, 2013

...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

283

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

284

Effect of processing parameters on the formation of spherical multinuclear microcapsules encapsulating peppermint oil by coacervation.  

PubMed

The gelatin/gum arabic multinuclear microcapsules encapsulating peppermint oil were prepared by coacervation. The effect of various processing parameters, including the core/wall ratio, wall material concentration, pH value, as well as stirring speed on the morphology, particle size distribution, yield and loading was investigated. When the wall material concentration or the core/wall ratio increased, the morphology of multinuclear microcapsules changed from spherical to irregular and the average particle size increased, the optimal wall material concentration and the core/wall ratio were 1% and 2:1, respectively. The multinuclear spherical microcapsules with desired mean particle size can be manufactured by modulating the pH value and stirring speed. The ideal preparation conditions were pH 3.7 at 400 rpm of stirring speed. The yield of multinuclear microcapsules encapsulating peppermint oil by coacervation was approximately 90% and the processing parameters had very slight influence on the yield. When transglutaminase was used as the cross-linker instead of formaldehyde, morphology, mean particle size, yield and loading remained the same as that hardening with formaldehyde, but the particle size distribution became narrower. PMID:17763057

Dong, Z J; Touré, A; Jia, C S; Zhang, X M; Xu, S Y

2007-11-01

285

Optimization of cold rolling process parameters in order to increasing rolling speed limited by chatter vibrations  

PubMed Central

Chatter has been recognized as major restriction for the increase in productivity of cold rolling processes, limiting the rolling speed for thin steel strips. It is shown that chatter has close relation with rolling conditions. So the main aim of this paper is to attain the optimum set points of rolling to achieve maximum rolling speed, preventing chatter to occur. Two combination methods were used for optimization. First method is done in four steps: providing a simulation program for chatter analysis, preparing data from simulation program based on central composite design of experiment, developing a statistical model to relate system tendency to chatter and rolling parameters by response surface methodology, and finally optimizing the process by genetic algorithm. Second method has analogous stages. But central composite design of experiment is replaced by Taguchi method and response surface methodology is replaced by neural network method. Also a study on the influence of the rolling parameters on system stability has been carried out. By using these combination methods, new set points were determined and significant improvement achieved in rolling speed.

Heidari, Ali; Forouzan, Mohammad R.

2012-01-01

286

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

287

Effect of process parameters on density of magnesium alloy parts by low-pressure expendable pattern casting  

Microsoft Academic Search

The combination of magnesium alloys with the low-pressure expendable pattern casting (LP-EPC) process would bright future for application of magnesium alloys. The researches are focused on the effect of process parameters on the internal casting quality of magnesium alloy parts. AZ91D magnesium alloy castings were produced for different combinations of the LP-EPC process parameters. Specifically, pouring temperature, vacuum, filling velocity

LI Ji-qiang; DONG Xuan-pu

288

Occupational noise exposure in small scale hand tools manufacturing (forging) industry (SSI) in Northern India.  

PubMed

Occupational noise has been recognized as hazardous for the human beings. A high noise level in forging shops is considered to lower the labour productivity and cause illness however occupational noise is being accepted as an integral part of the job. The present study has been carried out in 5 small scale hand tool forging units (SSI) of different sizes in Northern India in Punjab. Noise levels at various sections were measured. OSHA norms for hearing conservation has been incorporated which includes an exchange rate of 5 dB (A), criterion level at 90 dB (A), criterion time of 8 h, threshold level=80 dB (A), upper limit=140 dB (A) and with F/S response rate. Equivalent sound pressure level (L(eq)) has been measured in various sections of these plants. Noise at various sections like hammer section, cutting presses, punching, grinding and barrelling process was found to be >90 dB (A), which is greater than OSHA norms. A cross-sectional study on the basis of questionnaire has been carried out. The results of which revealed that 68% of the workers are not wearing ear protective equipments out of these 50% were not provided with PPE by the company. About 95% of the workers were suffering speech interference though high noise annoyance was reported by only 20%. It has been established that the maximum noise exposure is being taken by the workers as they are working more than 8h a day for six days per week. More than 90% workers are working 12 to 24 h over time per week which lead to very high noise exposure i.e. 50 to 80% per week higher than exposure time/week in USA or European countries(15, 16)). PMID:19672017

Singh, Lakhwinder Pal; Bhardwaj, Arvind; Deepak, K K; Bedi, Raman

2009-08-01

289

POD of ultrasonic detection of synthetic hard alpha inclusions in titanium aircraft engine forgings  

SciTech Connect

The probability of detection (POD) of inspection techniques is a key input to estimating the lives of structural components such as aircraft engines. This paper describes work conducted as a part of the development of POD curves for the ultrasonic detection of synthetic hard alpha (SHA) inclusions in titanium aircraft engine forgings. The sample upon which the POD curves are to be based contains four types of right circular SHAs that have been embedded in a representative titanium forging, as well as a number of flat bottomed holes (FBHs). The SHAs were of two sizes, number 3 and number 5, with each size including seeds with nominal nitrogen concentrations of both 3 and 17 wt. %. The FBHs included sizes of number 1, number 3, and number 5. This discreteness of the data poses a number of challenges to standard processes for determining POD. For example, at each concentration of nitrogen, there are only two sizes, with 10 inspection opportunities each. Fully empirical, standard methodologies such as a circumflex versus a provide less than an ideal framework for such an analysis. For example, there is no way to describe the beam limiting effect whereby the signal no longer increases the flaw grows larger than the beam, one can only determine POD at the two concentration levels present in the block, and confidence bounds tend to be broad because of the limited data available for each case. In this paper, we will describe strategies involving the use of physics-based models to overcome these difficulties by allowing the data from all reflectors to be analyzed by a single statistical model. Included will be a discussion of the development of the physics-based model, its comparison to the experimental data (obtained at multiple sites with multiple operators) and its implications regarding the statistical analysis, whose details will be given in a separate article by Li et al. in this volume.

Thompson, R. B. [Center for Nondestructive Evaluation and Departments of Materials Science and Aerospace Engineering, Iowa State University, Ames, IA 50011 (United States); Meeker, W. Q. [Center for Nondestructive Evaluation and Department of Statistics, Iowa State University, Ames, IA 50011 (United States); Brasche, L. J. H. [Center for Nondestructive Evaluation, Iowa State University, Ames, IA 50011 (United States)

2011-06-23

290

The effect of process parameters on the Liquid Flame Spray generated titania nanoparticles.  

PubMed

Nanoparticles have become important in many applications. It is essential to be able to control the particle size because the properties of nanoparticles change dramatically with particle size. An efficient way to generate nanoparticles is via aerosol processes. In this study we used Liquid Flame Spray consisting of liquid precursor droplets sprayed into a high-speed hydrogen/oxygen flame where they evaporate, vapours react and nucleate to form titania nanoparticles. Using flame methods, also dopants and sensitizers can easily be introduced in order to, e.g. improve the photocatalytic activity of the nanomaterial. To obtain a practical guideline in order to tailor the final nanoparticle size in the process, we have systematically studied the effects of different process parameters on the particle size of titania. Titania is used, e.g. as a photocatalyst, and then both particle size and crystal structure are important when looking at the efficiency. In this work, the generated nanoparticle size has been measured by aerosol instrumentation and the particle morphology has been verified with transmission electron microscopy. In Liquid Flame Spray method, there are several adjustable parameters such as precursor feed rate into the flame; concentration of the precursor; precursor material itself as well as solvent used in the precursor; mass flow of combustion gases and also the mechanical design of the torch used. We used metal organic based titanium precursors in alcohol solvents, predominantly ethanol and 2-propanol. Large differences in particle production between the precursors were found. Differences could also be seen for various solvents. As for precursor feed in the flame, the more mass is introduced the larger the nanoparticles are, i.e. precursor concentration and precursor feed rate have an impact on particle size. A similar phenomenon can be discovered for the combustion gas flow rates. Torch design also plays an important role in controlling the particle size. PMID:17950664

Aromaa, Mikko; Keskinen, Helmi; Mäkelä, Jyrki M

2007-11-01

291

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

292

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

293

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

294

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

295

Optimization of process parameters for the production of spray dried Ber (Ziziphus jujube L.) powder.  

PubMed

The study covers effect of operating variables of spray dryer i.e. inlet temperature (170, 180, 190, 200 and 210 °C,), aspirator blower capacity (40, 50, 60, 70 and 80 %) and feed pump capacity (9, 12, 15, 18, and 21 %) and processing parameters of feed i.e. total soluble solid (TSS) of feed (7.5 %) and encapsulating material, maltodextrin (4, 6, 8, 10, and 12 %), aerosil (1.0 %), citric acid (0.25 %) upon the physical properties (colour, packed density and hygroscopicity) of powder were observed. After complete evaluation and analysis of all the attributes for physical properties i.e. colour, packed density (0.45 g/cc) and hygroscopicity (0.17 g/g dry matter), it was concluded that best quality of Ber powder were obtained at inlet air temperature 190 °C, aspirator blower capacity 60 %, feed pump capacity 15 %, encapsulating material 8 %. PMID:25477666

Singh, V K; Pandey, Sheela; Pare, Akash; Singh, R B

2014-12-01

296

Choosing the parameters of the process of producing naphthalene for production of phthalic anhydride  

SciTech Connect

Phthalic anhydride production rates in the USSR require that added source of adequate purity of naphthalene feedstock be developed. Optimization studies of the feasibility of producing C/sub 10/H/sub 8/-feedstock by hydrocracking (500 Kpa; Al-Ca-Mo catalyst) from naphthalene-wash oil fraction from coal tar (Kemerovo Coke Works), using a benzene diluent (to suppress the formation of benzene homologues), reported herein provide process conditions which will permit commercial producton of high quality C/sub 10/H/sub 8/ and also sulfur-free benzene for caprobactum production. Optimum conditions were defined using the full factorial experiment method (independant variables: temperature and space-velocity), by regression analysis of output parameters (yields (%) of hyrogenate, C/sub 10/H/sub 8/, H/sub 2/, hydrocarbon gases, and coke and the melting point of the C/sub 10/H/sub 8/ fraction). At optimum conditions the yield of C/sub 10/H/sub 8/ was 105% of its feedstock content. These data reveal that in the range of conditions studied, temperature and space velocity exert opposing effects on the output parameters and that the system is nearly in the steady state condition.

Katsobashvili, Y.R.

1982-11-06

297

Evaluating the impact of cell culture process parameters on monoclonal antibody N-glycosylation.  

PubMed

Bioreactor process parameters influence the N-linked glycosylation profile of the produced monoclonal antibodies. A systematic assessment of their impact is a prerequisite for providing controllability over glycosylation, one of the most critical quality attributes of therapeutic antibodies. In this study we investigated the effect of single and combined chemical and mechanical stress parameters on the glycan microheterogeneity of an IgG1 antibody using a shift-experiment procedure in batch cultures. The N-linked glycosylation profile of the murine IgG1 was found to be highly complex since it included terminal galactosylation and sialylation, as well as variable core-fucosylation. Within a pH range of 6.8 to 7.8 differences in galactosylation and sialylation of approximately 50% were obtained. Variation of dissolved oxygen tension (10-90% air saturation) resulted in a maximum variability of 20% in galactosylation and 30% in sialylation. In contrast, no significant effect on the glycosylation profile was observed when osmolarity increased from 320 to 420mOsm/kg and sparging from 0.05 to 0.2vvm. In this study a better understanding of bioprocess-related factors affecting critical quality attributes under the scope of QbD is provided and can bring us one step closer towards desired and targeted glycosylation for future therapeutic proteins. PMID:25173615

Ivarsson, Marija; Villiger, Thomas K; Morbidelli, Massimo; Soos, Miroslav

2014-08-28

298

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

299

Hypertension and hematologic parameters in a community near a uranium processing facility  

SciTech Connect

Background: Environmental uranium exposure originating as a byproduct of uranium processing can impact human health. The Fernald Feed Materials Production Center functioned as a uranium processing facility from 1951 to 1989, and potential health effects among residents living near this plant were investigated via the Fernald Medical Monitoring Program (FMMP). Methods: Data from 8216 adult FMMP participants were used to test the hypothesis that elevated uranium exposure was associated with indicators of hypertension or changes in hematologic parameters at entry into the program. A cumulative uranium exposure estimate, developed by FMMP investigators, was used to classify exposure. Systolic and diastolic blood pressure and physician diagnoses were used to assess hypertension; and red blood cells, platelets, and white blood cell differential counts were used to characterize hematology. The relationship between uranium exposure and hypertension or hematologic parameters was evaluated using generalized linear models and quantile regression for continuous outcomes, and logistic regression or ordinal logistic regression for categorical outcomes, after adjustment for potential confounding factors. Results: Of 8216 adult FMMP participants 4187 (51%) had low cumulative uranium exposure, 1273 (15%) had moderate exposure, and 2756 (34%) were in the high (>0.50 Sievert) cumulative lifetime uranium exposure category. Participants with elevated uranium exposure had decreased white blood cell and lymphocyte counts and increased eosinophil counts. Female participants with higher uranium exposures had elevated systolic blood pressure compared to women with lower exposures. However, no exposure-related changes were observed in diastolic blood pressure or hypertension diagnoses among female or male participants. Conclusions: Results from this investigation suggest that residents in the vicinity of the Fernald plant with elevated exposure to uranium primarily via inhalation exhibited decreases in white blood cell counts, and small, though statistically significant, gender-specific alterations in systolic blood pressure at entry into the FMMP.

Wagner, Sara E., E-mail: swagner@uga.edu [College of Public Health, Department of Epidemiology and Biostatistics, Paul D. Coverdell Center for Biomedical and Health Sciences, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602-7396 (United States); Burch, James B. [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States) [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States); South Carolina Statewide Cancer Prevention and Control Program, Columbia, SC (United States); WJB Dorn Veteran's Affairs Medical Center, Columbia, SC (United States); Bottai, Matteo [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States)] [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States); Pinney, Susan M. [College of Medicine, Department of Environmental Health, University of Cincinnati, Cincinnati, OH (United States)] [College of Medicine, Department of Environmental Health, University of Cincinnati, Cincinnati, OH (United States); Puett, Robin [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States) [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States); South Carolina Statewide Cancer Prevention and Control Program, Columbia, SC (United States); Arnold School of Public Health, Department of Environmental Health Sciences, University of South Carolina, Columbia, SC (United States); Porter, Dwayne [Arnold School of Public Health, Department of Environmental Health Sciences, University of South Carolina, Columbia, SC (United States)] [Arnold School of Public Health, Department of Environmental Health Sciences, University of South Carolina, Columbia, SC (United States); Vena, John E. [College of Public Health, Department of Epidemiology and Biostatistics, Paul D. Coverdell Center for Biomedical and Health Sciences, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602-7396 (United States)] [College of Public Health, Department of Epidemiology and Biostatistics, Paul D. Coverdell Center for Biomedical and Health Sciences, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602-7396 (United States); Hebert, James R. [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States) [Arnold School of Public Health, Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC (United States); South Carolina Statewide Cancer Prevention and Control Program, Columbia, SC (United States)

2010-11-15

300

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 (40mg/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 (25V; RVSS) or high voltage (30V; 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

301

The Neutral Atmosphere Parameters on Measurements Using the Artificial Periodic Irregularities. Techniques, processing, results.  

NASA Astrophysics Data System (ADS)

The measurements with the aid of the artificial periodic irregularities (APIs) were begun in 1990. The APIs are created in the ionosphere illuminated by a high power HF radio wave of a frequency below the critical one. The APIs diagnostics is based upon observation of the Bragg backscatter of the pulsed probe radio waves from the periodic structure. The amplitudes and phases of the probe signals back scattered by the APIs are measured. At the E-region heights the APIs relax in the ambipolar diffusion process. Based on this fact we could determine the neutral atmosphere parameters suggesting that the processes of isothermal on small scales (3-5 km) and the electron, ion and neutral temperatures are equal at the E-region heights. The atmospheric height scale H and the neutral atmospheric temperature T are determined on the height dependence of the relaxation times tau(z). The altitude step is about 3 km. Whole height interval of the measurements of ? is equal to about 20-30 km. Selecting small height intervals step by step we obtain altitude dependences T(z), nu(z) and rho(z). Such a way was employed because the steady state is achieved on the scales 20-30 km for a long time. We obtained a lot of information about dynamical phenomena in the lower thermosphere. These results are presented in the report. Firstly, there were temperature profiles with minimum about 100-140 K above 100 km in the equinoctial periods. But in summer of 1999 temperature maximum was observed on z = 100 km. Secondary, there were often profiles with the wave-like variations and with the vertical scale of about to 4-6 km. The temporal variations of the atmospheric parameters had periods from 15 minutes to some hours. These variations caused by the propagation of the internal gravity and tide waves. Planetary waves produce the longer temporal variations. Thirdly, we observed some cases of the instability growth. The dependencies of the atmospheric parameters on the solar and geomagnetic activity were analyzed also. The work was supported in part by Russian Foundation for Basic Research, projects 13-02-97067, 13-05-00511 and 13-02-12074.

Tolmacheva, Ariadna V.; Bakhmetieva, Nataliya V.; Grigoriev; Kalinina, Elena E.

302

Prediction of relationships between hydrostatic coefficients and processing parameters of porous PZT ceramics by radial basis function  

Microsoft Academic Search

The high hydrostatic coefficients of porous piezoelectric materials provide the reduced acoustic impedance for the effective coupling with water medium as well as biological tissues. The hydrostatic strain coefficient (dh), voltage coefficients (gh) and longitudinal piezoelectric coefficient (d33) of porous piezoelectric materials has a strong dependence on processing parameters such as porosity parameter, polymer percentage, density and poling voltage. In

B. Praveenkumar; C. Vijayakumar; H. H. Kumar; D. K. Kharat

2009-01-01

303

The powder sintering and isothermal forging of Ti-10V-2Fe-3Al  

NASA Astrophysics Data System (ADS)

The synthetic technology of powder sintering and isothermal forging was explored to prepare a powder Ti-10V-2Fe-3Al (Ti-1023) alloy. Hydride-dehydride powder was provided from unqualified Ti-1023 ingot alloy because of “beta fleck” defect. After cold isostatic pressing and sintering, the compact presented uniform chemical composition, but lamella alpha microstructure. Isothermal forging technology was used to further densify the sintered compact and improve the microstructure and properties. The final forged compact exhibited equiaxed, recrystallized, and fined alpha phase microstructure, and excellent tensile properties at room temperature.

Guo, Hongzhen; Zhao, Zhanglong; Duan, Chunyan; Yao, Zekun

2008-11-01

304

The Effect of Corner Radii and Part Orientation on Fatigue Life of Closed-Forging Die  

NASA Astrophysics Data System (ADS)

An approach to optimal design of cold forging die is presented in this paper. The closed forging of the Universal joint was generated using three-dimensional CAD modeling software namely Solid works and analysis of stress and fatigue life were carried out. This study focused on the effects of corner radius of the die and part orientations to fatigue life of the die. The forging load is obtained by using Simplified Slab Method. The result indicate that corner radius and part orientation gives significant effect to reduction of stress on the die, thus increase the service life of the die.

Abdullah, A. B.; Ling, K. S.; Samad, Z.; Sahudin, S.

305

A study of processing parameters in thermal-sprayed alumina and zircon mixtures  

NASA Astrophysics Data System (ADS)

A method of plasma spraying of alumina and zircon mixtures to form ZrO2-mullite composites has been proposed and developed. The feedstock is prepared by a combination of mechanical alloying, which allows formation of fine-grained, homogeneous solid-solution mixtures, followed by plasma spheroidization that yields rapid solidified microstructures and enhanced compositional homogeneity. The effects of ball-milling duration and milling media were studied. It was found that zirconia is a more efficient milling media and that increasing milling duration enhanced the dissociation of zircon. Flame spray and plasma spray processes were used to spheroidize the spray-dried powders. The temperature of the flame spray was found to be insufficient to melt the powders completely. The processing parameters of the plasma spray played an important role in zircon decomposition and mullite formation. Increasing the arc current or reducing secondary gas pressure caused more zircon to decompose and more mullite to form after heat treatment at 1200 °C for 3 h. Dissociation of zircon and the amount of mullite for med can be enhanced significantly when using the more efficient, computerized plasma-spraying system and increasing the ball-milling duration from 4 to 8 h.

Li, Y.; Khor, K. A.

2002-06-01

306

Optimization of processing parameters and metrology for novel NCA negative resists for NGL  

NASA Astrophysics Data System (ADS)

It is expected that EUV resists must simultaneously pattern 20-nm half-pitch and below, with an LWR of <1.8 nm, and a sensitivity of 5-20 mJ/cm2. In order to make a resist perform optimally, new resist chemistry is required. One such approach being investigated by us is the development of polymeric non-CAR negative photo resists for sub 16 nm technology which is directly sensitive to radiation without utilizing the concept of chemical amplification (CARs). These resist designs are accomplished by homopolymers which are prepared from monomers containing sulfonium groups. We have achieved 20 nm patterns by e-beam lithography using this system. Here we will discuss in detail process parameters such as: spinning conditions for film thicknesses <50 nm and resulting surface topographies, baking regimes, exposure conditions and protocols on sensitivity, contrast, resolution and LER/LWR. Etch resistance data on these thin films will also be provided. Our results are aimed to provide a clear understanding of how these critical steps in the lithographic imaging process will affect extendibility of the non-CAR resist concept to sub 20 nanoscale features. Photodynamics and EUV exposure data will be covered.

Singh, Vikram; Satyanarayana, V. S. V.; Kessler, Felipe; Scheffer, Francine R.; Weibel, Daniel E.; Sharma, Satinder K.; Ghosh, Subrata; Gonsalves, Kenneth E.

2014-04-01

307

Formulation parameters of crystalline nanosuspensions on spray drying processing: a DoE approach.  

PubMed

Nanocrystalline suspensions offer a promising approach to improve dissolution of BCS class II/IV compounds. Spray drying was utilized as a downstream process to improve the physical and chemical stability of dried nanocrystals. The effect of nanocrystalline suspension formulation variables on spray-drying processing was investigated. Naproxen and indomethacin nanocrystalline formulations were formulated with either Dowfax 2A1 (small molecule) or HPMC E15 (high molecular weight polymer) and spray drying was performed. A DoE approach was utilized to understand the effect of critical formulation variables, i.e. type of stabilizer, type of drug, ratio of drug-to-stabilizer and drug concentration. The powders were analyzed for particle size, moisture content, powder X-ray diffraction and dissolution. A dialysis sac adapter for USP apparatus II was developed which provided good discrimination between aggregated and non-aggregated formulations. Nanocrystal aggregation was dependent on the drug-to-stabilizer ratio. The glass transition temperature and the charge effect played a dominant role on spray-dried powder yield. Those formulations with low drug-to-excipient ratios were less aggregating and showed faster dissolution compared to those formulations with high drug-to-excipient ratios. All stable (less aggregated) formulations were subjected to accelerated storage stability testing. The Flory-Huggins interaction parameter (between drug and excipients) correlated with the spray-dried nanocrystal formulations stability. PMID:24447788

Kumar, Sumit; Xu, Xiaoming; Gokhale, Rajeev; Burgess, Diane J

2014-04-10

308

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

309

Modeling the Influence of Process Parameters and Additional Heat Sources on Residual Stresses in Laser Cladding  

NASA Astrophysics Data System (ADS)

In laser cladding thermal contraction of the initially liquid coating during cooling causes residual stresses and possibly cracks. Preweld or postweld heating using inductors can reduce the thermal strain difference between coating and substrate and thus reduce the resulting stress. The aim of this work is to better understand the influence of various thermometallurgical and mechanical phenomena on stress evolution and to optimize the induction-assisted laser cladding process to get crack-free coatings of hard materials at high feed rates. First, an analytical one-dimensional model is used to visualize the most important features of stress evolution for a Stellite coating on a steel substrate. For more accurate studies, laser cladding is simulated including the powder-beam interaction, the powder catchment by the melt pool, and the self-consistent calculation of temperature field and bead shape. A three-dimensional finite element model and the required equivalent heat sources are derived from the results and used for the transient thermomechanical analysis, taking into account phase transformations and the elastic-plastic material behavior with strain hardening. Results are presented for the influence of process parameters such as feed rate, heat input, and inductor size on the residual stresses at a single bead of Stellite coatings on steel.

Brückner, F.; Lepski, D.; Beyer, E.

2007-09-01

310

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

311

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

SciTech Connect

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 {mu}m diameter micro-holes of 300 to 1,000 {mu}m depth in glass and ruby. The abrasive slurry contains B4C particles of 1 {mu}m to 5 {mu}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 {mu}m/s with ruby. Tool rotation, even for values as low as 50 rpm, increases productivity and improves holes geometry. Drilling with 1 {mu}m and 5 {mu}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 [Ecole Polytechnique Federale de Lausanne (EPFL), School of Engineering (STI), Mechanical Systems Design Laboratory - LCSM, Station No. 9, CH-1015 Lausanne (Switzerland)

2011-05-04

312

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

313

Bolt Manufacture: Process Selection  

E-print Network

Processes and Systems Prof. J.S. Colton © GIT 2009 6 #12;Powder ProcessingPowder Processing · Cold Dual action press ME 6222: Manufacturing Processes and Systems Prof. J.S. Colton © GIT 2009 8 #12;Cold / HeadingRolling / Heading · Roll the threads · Upset forge the headg ME 6222: Manufacturing Processes

Colton, Jonathan S.

314

Analysis of Axisymmetrical Compression Processes by the Finite Element Method  

NASA Astrophysics Data System (ADS)

In the study of compression processes, analytical methods use to be applied under plane strain conditions due to limitations of their own formulation. However, axisymmetrical workpieces are more commonly used in industrial processes, so the use of numerical methods is often neccesary. In this sense, the Finite Element Method (FEM) is a powerful numerical tool that can simulate more realistic conditions of these processes. In the study of compression processes between parallel flat dies (such as forging or indentation) several parameters are usually involved. The friction on the flat die-workpiece interface is is one of the most important parameters to be considered. Additionally, other factors mainly related to the geometrical dimensions of the problem are also relevant. Mainly, attending to the geometry of the problem different cases can be defined. Thus, the indentation and the forging of a cylindrical billet can be similarly studied assuming different dimensions of the dies and the workpiece, in each case. Thus, when the diameter of the workpiece is longer than the diameter of the die, indentation processes are developed. On the contrary, forging processes are distinguished when the diameter of the workpiece is shorter than the diameter of the die. In order to identify different cases to be solved for both types of compression processes a shape factor has been considered. This is defined as the ratio between the diameter and the height of the workpiece that is used to relate two dimensions of the process. Different axisymmetrical compression processes have been analysed by FEM in order to study the influence of the shape factor on the calculation of the required forces and contact pressure distributions. Results are compared between forging and indentation problems. The main conclusion of this study is that, for the same material, a change of the geometry can cause different values of the required energy to carry out the plastic deformation and also, different contact pressure distributions. With a right selection of the geometrical parameters, a more economical process and the extension of the tool life can be achieved.

Camacho, A. M.; Marin, M.; Sevilla, L.; Sebastian, M. A.

2007-05-01

315

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

Federal Register 2010, 2011, 2012, 2013

...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

316

5. VIEW OF 20TON STEAMPOWERED FORGE HAMMER Manufactured by Chambersburg ...  

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

5. VIEW OF 20-TON STEAM-POWERED FORGE HAMMER Manufactured by Chambersburg Engineering Company, Chambersburg, Pennsylvania - Juniata Shops, Blacksmith Shop No. 1, East of Fourth Avenue at Second Street, Altoona, Blair County, PA

317

Experiments in hot-rolling and forging of ductile cast iron  

SciTech Connect

The Bureau of Mines investigated hot-rolling and forging characteristics of experimental ductile iron castings both sand and permanent-mold, made with charges containing up to 70% foundry pig iron and 95% steelmaking pit iron. Between 1550 and 1950/sup 0/F, most castings could be rolled to 90% reduction or forged to 70% reduction without serious cracking. Charge and composition have less bearing on workability than on subsequent properties. Permanent mold castings could be worked as readily as sand castings at 1750 and 1950/sup 0/F. Plasticity improved with temperature. Small billets were also forged cold to 50% reduction without cracking. The feasibility of die-forging and bar-rolling of ductile iron was evaluated in trial tests conducted under a Bureau contract. Although workability and ductility of ductile iron are inferior to those of steel, more advantage could be taken of ductile iron's plasticity to work rough shapes to final dimensions.

Neumeier, L.A.; Betts, B.A.; Crosby, R.L.

1980-01-01

318

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

Microsoft Academic Search

The creation of parameter study suites has recently become a more challenging problem as the parameter studies have 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 seeking to combine several successive stages of parameterization and computation. Simultaneously, grid-based computing offers immense resource

Maurice Yarrow; Karen M. Mccann; Rupak Biswas; Rob F. Van Der Wijngaart

2000-01-01

319

The use of grey-based Taguchi methods to determine submerged arc welding process parameters in hardfacing  

Microsoft Academic Search

In this paper, the use of grey-based Taguchi methods for the optimization of the submerged arc welding (SAW) process parameters in hardfacing with considerations of multiple weld qualities is reported. In this new approach, the grey relational analysis is adopted to solve the SAW process with multiple weld qualities. A grey relational grade obtained from the grey relational analysis is

Y. S. Tarng; S. C. Juang; C. H. Chang

2002-01-01

320

Spray granulation: importance of process parameters on in vitro and in vivo behavior of dried nanosuspensions.  

PubMed

The use of fluid bed granulation for drying of pharmaceutical nanoparticulates on micron-sized granule substrates is a relatively new technique, with limited understanding in the current literature of the effects of process parameters on the physical properties of the dried nanoparticle powders. This work evaluated the effects of spray mode, spray rate and atomizing pressure for spray granulation of drug nanosuspensions through a systematic study. Naproxen and a proprietary Novartis compound were converted into nanosuspensions through wet media milling and dried onto a mannitol based substrate using spray granulation. For naproxen, various physical properties of the granules, as well as the in vitro re-dispersion and dissolution characteristics of the nano-crystals, were measured. It was found that the spray mode had the most drastic effect, where top spray yielded smaller re-dispersed particle sizes and faster release rates of drug from granules than bottom spray. This was attributed to the co-current spraying in bottom spray resulting in denser, homogenous films on the substrate. Similar in vitro results were obtained for the proprietary molecule, Compound A. In vivo studies in beagle dogs with Compound A showed no significant difference between the liquid and the dried forms of the nanosuspension in terms of overall AUC, differences were observed in the tmax which correlated with the rank ordering observed from the in vitro dissolution profiles. These findings make spray granulation amenable to the production of powders with desired processing and handling properties, without compromising the overall exposure of the compound under investigation. PMID:23916460

Figueroa, Carlos E; Bose, Sonali

2013-11-01

321

Mechanical properties of a forged Fe–25Al–2Ta steam turbine blade  

Microsoft Academic Search

The mechanical properties of samples taken from different parts of a 650 mm long steam turbine blade forged from Fe–25Al–2Ta (in at.%) by conventional forging on a counterblow hammer were examined. The hardness, brittle-to-ductile transition temperatures (BDTT), the yield stress in compression and in tension, and the creep behaviour were studied and compared with the same material in the as-cast and

P. Hanus; E. Bartsch; M. Palm; R. Krein; K. Bauer-Partenheimer; P. Janschek

2010-01-01

322

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

323

Influence of ion source configuration and its operation parameters on the target sputtering and implantation process  

SciTech Connect

In the work, investigation of the features and operation regimes of sputter enhanced ion-plasma source are presented. The source is based on the target sputtering with the dense plasma formed in the crossed electric and magnetic fields. It allows operation with noble or reactive gases at low pressure discharge regimes, and, the resulting ion beam is the mixture of ions from the working gas and sputtering target. Any conductive material, such as metals, alloys, or compounds, can be used as the sputtering target. Effectiveness of target sputtering process with the plasma was investigated dependently on the gun geometry, plasma parameters, and the target bias voltage. With the applied accelerating voltage from 0 to 20 kV, the source can be operated in regimes of thin film deposition, ion-beam mixing, and ion implantation. Multi-component ion beam implantation was applied to {alpha}-Fe, which leads to the surface hardness increasing from 2 GPa in the initial condition up to 3.5 GPa in case of combined N{sub 2}-C implantation. Projected range of the implanted elements is up to 20 nm with the implantation energy 20 keV that was obtained with XPS depth profiling.

Shalnov, K. V.; Kukhta, V. R.; Uemura, K. [Nagata Seiki Co, 8-2, Kamisuwa, Tsubame-shi, Niigata-ken, 959-0181 (Japan); Ito, Y. [Nagaoka University of Technology, Nagaoka, 940-2188 (Japan)

2012-06-15

324

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

325

Influence of ion source configuration and its operation parameters on the target sputtering and implantation process.  

PubMed

In the work, investigation of the features and operation regimes of sputter enhanced ion-plasma source are presented. The source is based on the target sputtering with the dense plasma formed in the crossed electric and magnetic fields. It allows operation with noble or reactive gases at low pressure discharge regimes, and, the resulting ion beam is the mixture of ions from the working gas and sputtering target. Any conductive material, such as metals, alloys, or compounds, can be used as the sputtering target. Effectiveness of target sputtering process with the plasma was investigated dependently on the gun geometry, plasma parameters, and the target bias voltage. With the applied accelerating voltage from 0 to 20 kV, the source can be operated in regimes of thin film deposition, ion-beam mixing, and ion implantation. Multi-component ion beam implantation was applied to ?-Fe, which leads to the surface hardness increasing from 2 GPa in the initial condition up to 3.5 GPa in case of combined N(2)-C implantation. Projected range of the implanted elements is up to 20 nm with the implantation energy 20 keV that was obtained with XPS depth profiling. PMID:22755619

Shalnov, K V; Kukhta, V R; Uemura, K; Ito, Y

2012-06-01

326

The method of general dimensional analysis applied to the determination of the parameters of the process of nitriding  

SciTech Connect

In the field of process characteristics for thermochemical treatments there is a contradiction between the great number of the parameters, that the experiment pointed out as determinants of the acquired results, and the small number of such kind of parameters that the Fick`s analytical laws can correlate. It can be ascertained that, a great deal of the complexity of diffusion processes is focused on the diffusion constant, as in the case of convection, where the coefficient of convection reflects the complexity of the process. The general dimensional analysis, created by the Romanian School of Experimental Physics as a development on a superior level of Rayleigh and Buckingham`s methods, can gather without exception, in analytical relations, all the parameters of the process of diffusion. The authors apply the method in the case of nitriding in nitrogen atmosphere with addition of ammonia.

Samoila, C.; Bot, D. [Transilvania-Univ. of Brasov (Romania)

1995-12-31

327

Optimization of injection molding process parameters using integrated artificial neural network model and expected improvement function method  

Microsoft Academic Search

In this study, an adaptive optimization method based on artificial neural network model is proposed to optimize the injection\\u000a molding process. The optimization process aims at minimizing the warpage of the injection molding parts in which process parameters\\u000a are design variables. Moldflow Plastic Insight software is used to analyze the warpage of the injection molding parts. The\\u000a mold temperature, melt

Huizhuo Shi; Yuehua Gao; Xicheng Wang

2010-01-01

328

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...

329

Anisotropic embrittlement in high-hardness ESR 4340 steel forgings  

SciTech Connect

ESR 4340 steel forgings tempered to a hardness of HRC 55 exhibit a severe loss of tensile ductility in the short transverse direction which is strain-rate and humidity dependent. The anisotropy is also reflected in blunt-notch Charpy impact energy, but is absent in the sharp-crack fracture toughness. Brittle behavior is associated with regions of smooth intergranular fracture aligned with microstructural banding Scanning Auger microprobe analysis indicates intergranular segregation of phosphorus and sulfur. The anisotropic embrittlement is attributed to an interaction of nonequilibrium segregation on solidification with local equilibrium segregation at grain boundaries during austenitizing. The regions are prone to brittle fracture under impact conditions and abnormal sensitivity to environmental attack during low strain-rate deformation. A relatively sparse distribution of these defects accounts for the discrepancy between smooth bar and blunt-notch tests vs sharp-crack tests. Isotropic properties are restored by homogenization treatment. For application of these steels at extreme hardness levels, homogenization treatment is essential.

Olson, G.B.; Anctil, A.A.; DeSisto, T.S.; Kula, E.B.

1983-08-01

330

Optimization of process parameters for foam-mat drying of papaya pulp.  

PubMed

Experiments were carried out to optimize the process parameters for production of papaya powder using foam-mat drying. Papaya pulp was foamed by incorporating methyl cellulose (0.25, 0.5, 0.75 and 1 %, w/w), glycerol-mono-stearate (1, 2, 3 and 4 %, w/w) and egg white (5, 10, 15 and 20 %, w/w) as foaming agents. The maximum stable foam formation was 72, 90 and 125% at 0.75 % methyl cellulose, 3 % glycerol-mono-stearate and 15 % egg white respectively with 9°Brix pulp and whipping time of 20 min. The foamed pulp was dried at air temperature of 60, 65 and 70 °C with foam thickness of 2, 4, 6, 8 and 10 mm in a batch type cabinet dryer. The drying time required for foamed papaya pulp was lower than non-foamed pulp at all selected temperatures. Biochemical analysis results showed a significant reduction in ascorbic acid, ?-carotene and total sugars in the foamed papaya dried product at higher foam thickness (6, 8 and 10 mm) and temperature (65 and 70 °C due to destruction at higher drying temperature and increasing time. There was no significant change in other biochemical constituents such as pH and acidity. The organoleptic and sensory evaluation of the quality attributes of papaya powder obtained from the pulp of 9°Brix added with 3 % glycerol-mono-stearate, whipped for 20 min and dried with a foam thickness of 4 mm at a temperature of 60 °C was found to be optimum to produce the foam-mat dried papaya powder. PMID:25328192

Kandasamy, Palani; Varadharaju, N; Kalemullah, S; Maladhi, D

2014-10-01

331

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

332

Optimization of Welding Parameters of Submerged Arc Welding Using Analytic Hierarchy Process (AHP) Based on Taguchi Technique  

NASA Astrophysics Data System (ADS)

The present paper reports a new procedure using an analytic hierarchy process (AHP) based Taguchi method for the selection of the best welding parameters to fabricate submerged arc welding of plain carbon steel. Selection of best welding parameters is an unstructured decision problem involving process parameters for multiple weldments. In the present investigation, three process parameter variables i.e. wire feed rate (Wf), stick out (So) and traverse speed (Ts) and the three response parameters i.e. penetration, bead width and bead reinforcement have been considered. The objective of the present work is thus to improve the quality of the welded elements by using AHP analysis based Taguchi method. Taguchi L16 orthogonal array is used to perform with less number of experimental runs. Taguchi approach is insufficient to solve a multi response optimization problem. In order to overcome this limitation, a multi criteria decision making method, AHP is applied in the present study. The optimal condition to have a quality weld (i.e. bead geometry) is found at 210 mm/min of wire feed rate, 15 mm of stick out and 0.75 m/min of traverse speed and also observed that the effect of wire feed rate on the overall bead geometry properties is more significant than other welding parameters. Finally, a confirmatory test has been carried out to verify the optimal setting so obtained.

Sarkar, A.; Roy, J.; Majumder, A.; Saha, S. C.

2014-04-01

333

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

334

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

335

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

336

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

337

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

338

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

2015-01-01

339

Effect of impulse vibration and noise on vasomotor function of peripheral blood vessels among pneumatic forge hammer operators.  

PubMed

An evaluation of the effect of impulse vibration and noise on vasomotor function of blood vessels among pneumatic forge hammer operators has been presented based on thermal tests (cooling). The study covered the following groups of workers; pneumatic forge hammer operators (I), pneumatic forging hammer operators (II), hammer operator's assistants (III), operators of forging presses and machines (IV) and the control group. The results of the study showed that in groups I and III it was impulse noise not vibration that caused changes in the functioning of peripheral blood vessels. PMID:9150980

Solecki, L

1995-01-01

340

ME 4210: Manufacturing Processes and Engineering -Prof. J.S. Colton GIT 2011  

E-print Network

Topics for final exam · Casting · Deformation processing ­ forging ­ extrusion · Sheet Metal Bending and Engineering - Prof. J.S. Colton © GIT 2011 6 Deformation processing · Forging · Extrusion #12;ME 4210 strain ­ not plane strain · Cold ­ strain hardening · Hot ­ strain rate · Plasticity, no elasticity #12

Colton, Jonathan S.

341

A NOVEL AUTO-PARAMETERS SELECTION PROCESS FOR IMAGE SEGMENTATION Yunzhi Jianga,b  

E-print Network

in recent years. Keywords: Image Segmentation; Multilevel Thresholding; Stratified Sampling; Tabu Search 1, the existing techniques that use the multilevel thresholding method in image segmentation are computationally parameter selection technique called an automatic multilevel thresholding algorithm using stratified

Cao, Longbing

342

Tensile behavior of an austenitic stainless steel subjected to multidirectional forging  

NASA Astrophysics Data System (ADS)

The mechanical behavior of a chromium-nickel austenitic stainless steel with submicrocrystalline structures produced by multidirectional forging (MDF) to a total strain of ~ 4 at temperatures of 700 and 600°C was studied. This processing resulted in the formation of uniform ultrafine grained structure with an average crystallite size of 360 and 300 nm, respectively, and high dislocation density. The tensile tests were carried out in a wide temperature range 20-650°C. At ambient temperature, the yield stress (YS) comprised 900 MPa and 730 MPa in the samples subjected to MDF at 600 and 700°C, respectively. It should be noted that this strength was achieved along with elongations of 16% and 22% in the samples subjected to MDF at 600 and 700°C. The YS decreased and elongation-to-failure tends to increase with increasing test temperature and approaching 235 MPa and 51%, respectively, at 650°C. Effect of temperature on mechanical behavior of stainless steel with submicrocrystalline structure is discussed.

Tikhonova, M.; Sorokopudova, J.; Bondareva, E.; Belyakov, A.; Kaibyshev, R.

2014-08-01

343

Three-dimensional resistivity tomography of Vulcan's forge, Vulcano Island, southern Italy  

NASA Astrophysics Data System (ADS)

9,525 DC resistivity measurements were taken along 9 profiles crossing the volcanic edifice of La Fossa di Vulcano (the forge of God Vulcan in ancient Roman mythology), Vulcano Island (Italy) using a total of 958 electrode locations. This unique data set has been inverted in 3D by minimizing the L2 norm of the data misfit using a Gauss-Newton approach. The true 3D inversion was performed using parallel processing on an unstructured tetrahedral mesh containing 75,549 finite-element nodes and 398,208 elements to accurately model the topography of the volcanic edifice. The 3D tomogram shows a very conductive body (>0.1 S/m) comprised inside the Pietre Cotte crater with conductive volumes that are consistent with the position of temperature and CO2 anomalies at the ground surface. This conductive body is interpreted as the main hydrothermal body. It is overlaid by a resistive and cold cap in the bottom of the crater. The position of the conductive body is consistent with the deformation source responsible for the observed 1990-1996 deflation of the volcano associated with a decrease of hydrothermal activity.

Revil, A.; Johnson, T. C.; Finizola, A.

2010-08-01

344

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

345

Statistical analysis and optimization of process parameters in Ti6Al4V laser cladding using Nd:YAG laser  

NASA Astrophysics Data System (ADS)

The process parameters of laser cladding have great effect on the clad geometry and dilution. This investigation focuses on the influence of laser power (400-600 W), scanning speed (500-700 mm/min) and powder feed rate (30-60 rev/min) on the shape factor and the cladding-bead geometry (layer width, layer height and molten depth) with regard to injecting Ti6Al4V (TC4) powder on TC4 substrate. The experimental design technique, central composite design (CCD) and response surface methodology (RSM) are used to build the mathematical model. By means of the developed model tested by the analysis of variance (ANOVA) method, the relationship between process parameters and output responses and the interaction among the process parameter are analyzed and discussed in detail. The analysis results indicate that powder feed rate is the dominant factor on the width and height of cladding coating while laser scanning speed has the strongest effect on molten depth of substrate. Finally, the validation results show that the calculated values are in good agreement with measured responses within the allowable range of cladding parameters being used. This makes it possible to acquire a good parameter combination for dilution control. Based on the results of optimization, it is observed that the low level of laser power and high level of laser scanning speed can produce cladding coatings with good quality when powder feed rate is around the center value.

Sun, Yuwen; Hao, Mingzhong

2012-07-01

346

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

347

Processing parameters influencing the sintering of alumina in a conventional and 14 GHz microwave furnace  

SciTech Connect

Experimental design and measurement results are presented for processing conditions that affect the final density of conventionally-sintered and microwave-sintered alumina. The microwave-sintered specimens were processed in a 14 GHz multimoded cavity. Statistical experimental design methods were used to examine the roles of process temperature, soak time, and heating rate in both furnaces. Future experiments are outlined to ascertain if optimum processing conditions also translate to improvements in engineering properties such as fracture strength and indentation toughness.

Grellinger, D.J.; Booske, J.H.; Freeman, S.A.; Cooper, R.F. [Univ. of Wisconsin, Madison, WI (United States)

1995-12-31

348

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

349

Optimisation of Lime-Soda process parameters for reduction of hardness in aqua-hatchery practices using Taguchi methods.  

PubMed

This paper presents the optimisation of Lime-Soda process parameters for the reduction of hardness in aqua-hatchery practices in the context of M. rosenbergii. The fresh water in the development of fisheries needs to be of suitable quality. Lack of desirable quality in available fresh water is generally the confronting restraint. On the Indian subcontinent, groundwater is the only source of raw water, having varying degree of hardness and thus is unsuitable for the fresh water prawn hatchery practices (M. rosenbergii). In order to make use of hard water in the context of aqua-hatchery, Lime-Soda process has been recommended. The efficacy of the various process parameters like lime, soda ash and detention time, on the reduction of hardness needs to be examined. This paper proposes to determine the parameter settings for the CIFE well water, which is pretty hard by using Taguchi experimental design method. Orthogonal Arrays of Taguchi, Signal-to-Noise Ratio, the analysis of variance (ANOVA) have been applied to determine their dosage and analysed for their effect on hardness reduction. The tests carried out with optimal levels of Lime-Soda process parameters confirmed the efficacy of the Taguchi optimisation method. Emphasis has been placed on optimisation of chemical doses required to reduce the total hardness using Taguchi method and ANOVA, to suit the available raw water quality for aqua-hatchery practices, especially for fresh water prawn M. rosenbergii. PMID:24749379

Yavalkar, S P; Bhole, A G; Babu, P V Vijay; Prakash, Chandra

2012-04-01

350

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

351

Selection of EDM Process Parameters Using Biogeography-Based Optimization Algorithm  

Microsoft Academic Search

Amongst the nontraditional machining processes, electric discharge machining (EDM) is considered to be one of the most important processes for machining intricate and complex shapes in various electrically conductive materials, including high-strength, temperature-resistant (HSTR) alloys, especially in aeronautical and automotive industries. For achieving the best performance of the EDM process, it is imperative to carry out parametric design which involves

Rajarshi Mukherjee; Shankar Chakraborty

2012-01-01

352

Effect of Die Strength and Work Piece Strength on the Wear of Hot Forging Dies  

NASA Astrophysics Data System (ADS)

The effect of the strength ratio extracted from an Archard model for wear is used to describe the wear rates expected in hot forging dies. In the current study, the strength ratio is the strength of the hot forging die to the strength of the work piece. Three hot forging die steels are evaluated. The three die steels are FX, 2714, and WF. To determine the strength of the forging die, a continuous function has been developed that describes the yield strength of three die steels for temperatures from 600 to 700 °C and for times up to 20 h (i.e., tempering times of up to 20 h). The work piece material is assumed to be AISI 1045. Based on the analysis, the wear resistance of WF should be superior and FX should be slightly better than 2714. Decreasing the forging temperature increases the strength ratio, because the strength of the die surface increases faster than the flow strength of AISI 1045. The increase in the strength ratio indicates a decrease in the expected wear rate.

Levy, B. S.; Van Tyne, C. J.

2015-01-01

353

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

354

Processing of materials—monolithic to composites  

Microsoft Academic Search

A multimillion rupee 500-ton hydraulic extrusion\\/forging facility established at NPL, New Delhi, has been used to undertake\\u000a extensive studies in forming, the process of plastically deforming, which is the most important way of shaping materials.\\u000a Wrought materials are used extensively for making useful products employing extrusion and forging, the two important secondary\\u000a processing techniques used to convert materials into useful

Anil K Gupta

1995-01-01

355

Joining Part 1g ME 6222: Manufacturing Processes and Systems  

E-print Network

: Manufacturing Processes and Systems Prof. J.S. Colton © GIT 2009 3 #12;Welding using interfacial shear - Cold (forged) against each other to complete the bond. ME 6222: Manufacturing Processes and Systems Prof. J

Colton, Jonathan S.

356

Selection of EDM Process Parameters Using Biogeography-Based Optimization Algorithm  

Microsoft Academic Search

Amongst the non-traditional machining processes, electric discharge machining (EDM) is considered to be one of the most important processes for machining intricate and complex shapes in various electrically conductive materials, including high-strength, temperature-resistant (HSTR) alloys, especially in aeronautical and automotive industries. For achieving the best performance of the EDM process, it is imperative to carry out parametric design which involves

Rajarshi Mukherjee; Shankar Chakraborty

2011-01-01

357

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

358

The Order Parameter and the Servo Process of Safety Management System of Coal Mine Construction Project  

Microsoft Academic Search

In order to solve the order parameter of safety management system of coal mine construction project, to find out movement role of the system, this paper analyzes the sub-systems and the interaction between the various elements of safety management system in the coal mine construction project and builds the cooperative evolution mathematical model. At the same time, the paper also

Jingyang Zhang; Songjiang Wang

2011-01-01

359

Processing of crystals with controlled lattice parameter gradient by the LHPG technique  

Microsoft Academic Search

The existing methods to prepare crystals with controlled lattice parameters gradients are based on techniques that use accurate programmable temperature control and, often, a crucible. Little efforts have been made to adapt a crucibleless technique to prepare this kind of materials. Here we report on a procedure to design and grow crystals of any multinary oxide system having this property

L. B. Barbosa; D. Reyes Ardila; E. M. Kakuno; R. H. Camparin; C. Cusatis; J. P. Andreeta

2003-01-01

360

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

361

A review of signal processing used in the implementation of the pulse oximetry photoplethysmographic fluid responsiveness parameter.  

PubMed

?POP is a physiological parameter derived from the respiration-induced change in the pulse oximetry plethysmographic (POP) waveform or "pleth." It has been proposed as a proxy for pulse pressure variation used in the determination of the response to intravascular volume expansion in hypovolemic patients. Many studies have now reported on the parameter, and many research groups have constructed algorithms for its computation from the first principles where the implementation details have been described. This review focuses on the signal processing aspects of ?POP, as reported in the literature, and aims to provide a comprehensive summary of the wide-ranging algorithmic strategies that have been attempted in its computation. A search was conducted for articles concerning the use of ?POP as a fluid responsiveness parameter. In particular, articles concerning the correlation between ?POP and pulse pressure variation were targeted. Comments and replies to comments by the authors in which signal processing aspects were discussed were also included in the review. The parameter is first defined, and a history of the early work surrounding pleth-based fluid responsiveness parameters is presented. This is followed by an overview of the signal processing methods used in the reported studies, including details of exclusion criteria, manual filtering (preprocessing), gain change issues, acquisition details, selection of registration periods, averaging methods, physiological influences on the pleth, and comments by the investigators themselves. It is concluded that to develop a robust, fully automated ?POP algorithm for use in the clinical environment, more rigorous signal processing is required. Specifically, signals should be evaluated over significant periods of time, with emphasis on the quality and temporal relevance of the information. PMID:25405691

Addison, Paul S

2014-12-01

362

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

363

The optimization of processing parameters used to form aluminum oxide-styrene acrylate composite capacitors  

Microsoft Academic Search

The dielectric characteristics, thickness and the glass transition temperature of composite dielectric coatings containing electrophoretically deposited styrene acrylate plus anodically formed aluminum oxide can be altered by varying the processing conditions. The processing conditions varied here include: (1) the nature of the anodic aluminum oxide (barrier vs porous AlâOâ), (2) the thickness of the aluminum oxide, and (3) the curing

J. K. G. Panitz; W. G. Yelton

1989-01-01

364

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

365

On-Line Processing of Unidirectional Fiber Composites Using Radiative Heating: II. Radiative Properties, Experimental Validation and Process Parameter Selection  

Microsoft Academic Search

Experimental validation is presented for a detailed thermal model (described in Paper I) for on-line processing of unidirectional fiber composites by surface or volumetric radiative heating. Surface and volumetric radiative properties of unidirectional graphite\\/epoxy and glass\\/epoxy are presented: measurements of the complex refractive index of an uncured and cured 3501-6 epoxy resin as a function of wavelength; semi-empirical extinction and

Bih-Cherng Chern; Tess J. Moon; John R. Howell

2002-01-01

366

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

367

Sequential Processing of Data: The Future of Inverse Modeling and Parameter Estimation? (Outstanding Young Scientist Lecture)  

NASA Astrophysics Data System (ADS)

Several recent contributions to the hydrologic literature have demonstrated an inability of standard model evaluation criteria to adequately distinguish between different parameter sets and competing model structures, particulary when dealing with highly complex environmental models and significant structural error. The widespread approach to model evaluation that summarizes the mismatch, En = {ek;k = 1,...,n} = Yn -˜Yn between n model predictions, Yn and corresponding observations, ˜Yn in a single aggregated measure of length of the residuals, F not only introduces equifinality but also complicates parameter estimation. Here we introduce the Differential Evolution Particle Filter (DEPF) to better reconcile models with observations. Our method uses sequential likelihood updating to provide a recursive mapping of {e1,...,en}? F . As main building block DEPF uses the DREAM adaptive MCMC scheme presented in Vrugt et al. (2008, 2009). Two illustrative case studies using conceptual hydrologic modeling show that DEPF (1) requires far fewer particles than conventional Sequential Monte Carlo approaches to work well in practice, (2) maintains adequate particle diversity during all stages of filter evolution, (3) provides important insights into the information content of discharge data and non-stationarity of hydrologic model parameters, and (4) is embarrassingly parallel and therefore designed to solve computationally demanding hydrologic models. Our DEPF code follows the formal Bayesian paradigm, yet readily accommodates informal likelihood functions or signature indices if those better represent the salient features of the data and simulation model.

Vrugt, Jasper A.

2010-05-01

368

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

369

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

370

Microstructural evolution of a delta containing nickel-base superalloy during heat treatment and isothermal forging  

E-print Network

can result in hot shortness and cracking, whilst the forging stresses at low temperatures become unacceptably high, requiring specialised dies, and can lead to inhomogeneous deformation of the alloy as well as fracture of the forging [13... and 8.3 mm length taken from the as-HIP compact. Specimens were inserted into the pre–heated furnace and given a 35 minute soak, to ensure thermal equilibrium. Compression testing was completed using a servo-hydraulic ESH 016606 rig, with two N...

Mignanelli, P. M.; Jones, N. G.; Perkins, K. M.; Hardy, M. C.; Stone, H. J.

2014-11-06

371

The effect of processing parameters on oil content of corn tortilla chips  

E-print Network

with super-heated steam to produce potato chips with 23'/o fat. This is about 50'%%d lower than controls. Other processes involve coating raw potatoes with chemical compounds, such as polyvinylpyrrolidone, to prevent oil adsorption (Prosise and Ramsey...

Dudley, Peta Rock

2012-06-07

372

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

373

The effect of process parameters on audible acoustic emissions from high-shear granulation.  

PubMed

Product quality in high-shear granulation is easily compromised by minor changes in raw material properties or process conditions. It is desired to develop a process analytical technology (PAT) that can monitor the process in real-time and provide feedback for quality control. In this work, the application of audible acoustic emissions (AAEs) as a PAT tool was investigated. A condenser microphone was placed at the top of the air exhaust on a PMA-10 high-shear granulator to collect AAEs for a design of experiment (DOE) varying impeller speed, total binder volume and spray rate. The results showed the 10 Hz total power spectral densities (TPSDs) between 20 and 250 Hz were significantly affected by the changes in process conditions. Impeller speed and spray rate were shown to have statistically significant effects on granulation wetting, and impeller speed and total binder volume were significant in terms of process end-point. The DOE results were confirmed by a multivariate PLS model of the TPSDs. The scores plot showed separation based on impeller speed in the first component and spray rate in the second component. The findings support the use of AAEs to monitor changes in process conditions in real-time and achieve consistent product quality. PMID:22564031

Hansuld, Erin M; Briens, Lauren; Sayani, Amyn; McCann, Joe A B

2013-02-01

374

Numerical Simulation of Damage during Forging with Superimposed Hydrostatic Pressure by Active Media  

SciTech Connect

The effective reduction of energy consumption and a reasonable treatment of resources can be achieved by minimizing a component's weight using lightweight metals. In this context, aluminum alloys play a major role. Due to their material-sided restricted formability, the mentioned aluminum materials are difficult to form. The plasticity of a material is ascertained by its maximum forming limit. It is attained, when the deformation causes mechanical damage within the material. Damage of that sort is reached more rapidly, the greater the tensile strength rate in relation to total tension rate. A promising approach of handling these low ductile, high-strength aluminum alloys within a forming process, is forming with a synchronized superposition of comprehensive stress by active media such as by controlling oil pressure. The influence of superimposed hydrostatic pressure on the flow stress was analyzed as well as the formability for different procedures at different hydrostatic pressures and temperature levels. It was observed that flow stress is independent of superimposed hydrostatic pressure. Neither the superimposed pressure has an influence on the plastic deformation, nor does a pressure dependent material hardening due to increasing hydrostatic pressure take place. The formability increases with rising hydrostatic pressure. The relative gain at room temperature and increase of the superimposed pressure from 0 to 600 bar for tested materials was at least 140 % and max. 220 %. Therefore in this paper, based on these experimental observations, it is the intended to develop a numerical simulation in order to predict ductile damage that occurs in the bulk forging process with superimposed hydrostatic pressure based Lemaitre's damage model.

Behrens, B.-A.; Hagen, T.; Roehr, S.; Sidhu, K. B. [Institute for Metal Forming and Metal-Forming Machines, Leibniz University of Hanover, An der Universitaet 2, 30823 Garbsen (Germany)

2007-05-17

375

Optimization and Modeling of Process Parameters for Lipase Production by Bacillus brevis  

Microsoft Academic Search

Statistical evaluation of fermentation conditions and nutritional factors by Plackett–Burman two-level factorial design followed\\u000a by optimization of significant parameters using response surface methodology for lipase production by Bacillus brevis was performed in submerged batch fermentation. Temperature, glucose, and olive oil were found to be the significant factors\\u000a affecting lipase production. Maximum lipase activity of 5.1 U ml?1 and cell mass of 1.82 g l?1

Aravindan Rajendran; Viruthagiri Thangavelu

376

The effect of process parameters on the thermal conditions during moving mold ESR  

SciTech Connect

Several experimental melts were conducted using a moving mold electroslag remelting furnace. The conditions of electrode immersion depth, slag cap thickness, and melt current were varied. Mold wall temperatures and slag pool temperatures were measured and the heat flux through the mold wall was calculated. The relationships between varying ESR melt parameters and the resultant thermal conditions were examined. The thermal profile of the mold, the heat transfer to the mold coolant total and fractional, and the formation of a slag skin were studied.

Heilman, J.E. [Carpenter Technology Corp., Reading, PA (United States); Damkroger, B.K. [Sandia National Labs., Albuquerque, NM (United States)

1994-09-01

377

Phase behavior and process parameters effects on the characteristics of precipitated theophylline using carbon dioxide as antisolvent  

Microsoft Academic Search

Microparticles of theophylline were recrystallized using the high-pressure antisolvent technique. A mixture of ethanol and dichloromethane with a volumetric ratio of 1:1 was used as solvents, and compressed CO2 as antisolvent. The effects of process parameters (temperature, flow rate of solution and antisolvent, drying rate, initial solution concentration, diameter and length of the capillary expansion tube, and pressure gradient between

Elton Franceschi; Marcos H. Kunita; Marcus V. Tres; Adley F. Rubira; Edvani C. Muniz; Marcos L. Corazza; Cláudio Dariva; Sandra R. S. Ferreira; J. Vladimir Oliveira

2008-01-01

378

Optimization of Processing Parameters During Laser Cladding of ZE41AT5 Magnesium Alloy Castings Using Taguchi Method  

Microsoft Academic Search

A continuous wave 4 kW Nd:YAG laser welding system was employed to clad single beads on machined 6.2-mm thick ZE41A-T5 aerospace magnesium alloy sand castings using nominal 1.6-mm filler rods of the parent metal. Based on the quality criterion of minimum dilution ratio, the Taguchi experimental method was used to optimize different process parameters and to identify the dominating factors. It

X. Cao; M. Xiao; M. Jahazi; J. Fournier; M. Alain

2008-01-01

379

Effectiveness of low power dual-V t designs in nano-scale technologies under process parameter variations  

Microsoft Academic Search

This paper explores the effectiveness of dual-Vt design under aggressive scaling of technology, which results in significant increase in all components of leakage (subthreshold, gate and junction tunneling) while having large variations in process parameters. The present way of realizing high-Vt devices results in high junction tunneling leakage compared to low-Vt devices, which in turn may result in negligible leakage

Amit Agarwal; Kunhyuk Kang; Swarup K. Bhunia; James D. Gallagher; Kaushik Roy

2005-01-01

380

Mueller-matrix processing of biological tissues polarization images and reconstruction of parameters phase and amplitude anisotropy  

NASA Astrophysics Data System (ADS)

A new azimuthally stable polarimetric method for processing of microscopic images of optically anisotropic structures of different biological layers histological sections is proposed. A new model of phase anisotropy definition of biological tissues by using superposition of Mueller matrices of linear birefringence and optical activity is proposed. The matrix element M44 has been chosen as the main information parameter, which value is independent of rotation angle of both sample and probing beam polarization plane.

Ushenko, V. O.; Prysyazhnyuk, V. P.; Dubolazov, O. V.; Karachevtsev, A. O.; Motrich, A. V.; Sobko, O. V.; Olar, O. I.

2014-09-01

381

Influence of process parameter variation on the reflectivity of sputter-deposited W-C multilayer diffraction gratings  

NASA Technical Reports Server (NTRS)

Multilayer W-C diffraction gratings with nominal d spacings of 35 A have been fabricated by magnetron sputter deposition. The peak and integrated reflectivities of these films have been measured with Al K-alpha X-rays and compared to theoretical values. The rms surface roughness has been evaluated. The influence of several sputtering-system process parameters on the reflectivities has been investigated.

Sager, B.; Benson, P.; Jahoda, K.; Jacobs, J. R.; Bloch, J. J.

1986-01-01

382

Computational Analysis of the Effects of Process Parameters on Molten Pool Transport in Cu-Ni Dissimilar Laser Weld Pool  

Microsoft Academic Search

A three-dimensional, transient numerical model is used for analyzing the effects of process parameters such as laser power and the laser scanning speed on turbulent momentum, heat and mass transport in a typical dissimilar metal weld pool of a copper-nickel binary couple. The conservation equations are solved in a coupled manner using a semi-implicit pressure linked algorithm in the framework

Alexandros K. Skouras; Nilanjan Chakraborty; Suman Chakraborty

2010-01-01

383

Site-specific analysis of radiological and physical parameters for cobbly soils at the Gunnison, Colorado, processing site. Revision 1  

SciTech Connect

The remedial action at the Gunnison, Colorado, processing site is being performed under the Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978. Under UMTRCA, the US Environmental Protection Agency (EPA) is charged with the responsibility of developing appropriate and applicable standards for the cleanup of radiologically contaminated land and buildings at 24 designated sites, including the Gunnison, Colorado, inactive processing site. Section 108 of Public Law 95-604 states that the US Department of Energy (DOE) shall ``select and perform remedial actions at the designated processing sites and disposal sites in accordance with the general standards`` prescribed by the EPA. Regulations governing the required remedial action at inactive uranium processing sites were promulgated by the EPA in 1983 and are contained in 40 CFR Part 192 (1993), Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings. This document describes the radiological and physical parameters for the remedial action of the soil.

Not Available

1994-01-01

384

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

385

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

386

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

387

Application of the severity parameter for predicting viscosity during hydrothermal processing of dewatered sewage sludge for a commercial PFBC plant.  

PubMed

Dewatered sewage sludge (approximately 80% water, but with low fluidity) was liquidized by hydrothermal treatment in order to make coal-water paste (CWP) for use in a pressurized-fluidized-bed-combustion (PFBC) power plant. Prediction of the viscosity of the dewatered sewage sludge during batch reactor hydrothermal liquefaction is important in order to avoid inputting excess energy. A single parameter, the severity parameter, has been used to predict viscosity during the hydrothermal process. The relationship between the viscosity of the slurry made from dewatered sewage sludge and the severity value was investigated. Viscosity reduction was associated with an increase in the severity value and was dependent on reaction temperature and time. It was concluded that predicting the viscosity of dewatered sewage sludge during the hydrothermal process by means of the severity parameter is possible. This method is expected to provide a useful guideline for choosing reaction conditions based on prediction of the viscosity of the sludge slurry during the hydrothermal process. PMID:19850471

Yanagida, Takashi; Fujimoto, Shinji; Minowa, Tomoaki

2010-03-01

388

Stability of ultrafine-grained microstructure in fcc metals processed by severe plastic deformation  

E-print Network

was investigated for Cu samples processed by Equal-Channel Angular Pressing (ECAP), High-Pressure Torsion (HPT such as Equal-Channel Angular Pressing (ECAP), High-Pressure Torsion (HPT), Multi-Directional Forging (MDF), Multi-Directional Forging and Twist Extrusion at room temperature (RT). It is found that HPT results

Gubicza, Jenõ

389

FORMABILITY INVESTIGATIONS FOR THE HOT STAMPING PROCESS Y. Dahan 1&2,*  

E-print Network

, a numerical model of these hot stamping tests has been developed with finite element softwares (Forge2® , Forge3® and Abaqus). The numerical simulations confirm the location and the magnitude of the blank by the cold tools. The cooling rate of this process step allows obtaining the desired martensitic

Paris-Sud XI, Université de

390

A note on the consistent estimation of spatial-temporal point process parameters  

E-print Network

Schoenberg Department of Statistics, University of California, Los Angeles, CA 90095­1554, USA. phone: 310-Science Building Los Angeles, CA 90095­1554, USA. 1 #12;Abstract For models used to describe spatial. In point process models for earthquake occurrences, for instance, the distribution of earthquake mag

Schoenberg, Frederic Paik (Rick)

391

An evolutionary approach to parameter optimisation of submerged arc welding in the hardfacing process  

Microsoft Academic Search

The Submerged Arc Welding (SAW) process finds wide industrial application due to its easy applicability, high current density and ability to deposit a large amount of weld metal using more than one wire at the same time. It is highly emphasised in manufacturing especially because of its ability to restore worn parts. SAW is characterised by a large number of

Amar Patnaik; Sandhyarani Biswas; S. S. Mahapatra

2007-01-01

392

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...

393

Electrochemical machining of super-hydrophobic Al surfaces and effect of processing parameters on wettability  

NASA Astrophysics Data System (ADS)

Super-hydrophobic aluminum (Al) surfaces were successfully fabricated via electrochemical machining in neutral NaClO3 electrolyte and subsequent fluoroalkylsilane (FAS) modification. The effects of the processing time, processing current density, and electrolyte concentration on the wettability, morphology, and roughness were studied. The surface morphology, chemical composition, and wettability of the Al surfaces were investigated using scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS), white-light interferometry, roughness measurements, X-ray diffraction (XRD), Fourier-transform infrared spectrometry (FTIR), and optical contact angle measurements. The results show that hierarchical rough structures and low surface energy films were present on the Al surfaces after electrochemical machining and FAS modification. The combination of the rough structures and the low surface energy materials plays a crucial role in achieving super-hydrophobicity. Compared with the anodic oxidation and chemical etching method, the method proposed in our work does not require strong acid or alkali, and causes less harm to the environment and operators but with high processing efficiency. The rough structures required by the super-hydrophobic surfaces were obtained at 30-s processing time and the best super-hydrophobicity with 164.6? water contact angle and 2? tilting angle was obtained at 360 s. The resulting super-hydrophobic Al surfaces have a long-time stability in air and an excellent resistance to corrosive liquids.

Song, Jin-long; Xu, Wen-ji; Liu, Xin; Lu, Yao; Sun, Jing

2012-09-01

394

Seychelles' sea cucumber fishery: Data on processed products and other parameters  

Microsoft Academic Search

The sea cucumber fishery in the Seychelles has recently experienced rapid development. In order to imple - ment a management plan for this fishery, more data are needed on the fished products, their processing and general socioeconomics. In this article, we present new data on the sea cucumber products obtained from the five main holothurian species fished. These data will

Riaz Aumeeruddy; Chantal Conand

2007-01-01

395

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

396

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

397

Influence of Process Parameters on Microstructure and Mechanical Properties of Friction-Stir-Processed Mg-Gd-Y-Zr Casting  

NASA Astrophysics Data System (ADS)

Mg-10Gd-3Y-0.5Zr (wt pct) casting was subjected to friction stir processing (FSP) at a constant rotation rate of 800 rpm and varied travel speeds of 25, 50, and 100 mm/minute. FSP resulted in the generation of fine-grained microstructure and fundamental dissolution of coarse Mg5(Gd,Y) phase at the grain boundaries, thereby enhancing the tensile properties significantly at both room and elevated temperatures. The grain size of the FSP samples decreased with the increasing travel speed, whereas the microstructure heterogeneity with the banded structure (onion rings) became evident at a higher travel speed. Tensile elongation of the FSP samples increased as the travel speed increased, whereas the highest strengths were obtained at the medium travel speed of 50 mm/minute. Higher strengths and greater elongations were observed for the FSP samples in the transverse direction (TD) than in the longitudinal direction (LD). After post-FSP aging, the strengths of the FSP samples were increased significantly with the TD and LD exhibiting the same strengths; however, the elongation was decreased remarkably with the TD having higher elongation than the LD. A variation of the tensile properties was discussed in detail based on the microstructure heterogeneity and fracture surfaces.

Yang, Q.; Xiao, B. L.; Ma, Z. Y.

2012-06-01

398

EVOLUTION OF BRIGHTEST CLUSTER GALAXY STRUCTURAL PARAMETERS IN THE LAST {approx}6 Gyr: FEEDBACK PROCESSES VERSUS MERGER EVENTS  

SciTech Connect

We present results on the evolution of the structural parameters of two samples of brightest cluster galaxies (BCGs) in the last 6 Gyr. The nearby sample of BCGs consists of 69 galaxies from the WINGS survey spanning a redshift range of 0.04 < z < 0.07. The intermediate-redshift (0.3 < z < 0.6) sample is formed by 20 BCGs extracted from the Hubble Space Telescope archive. Both samples have similar spatial resolution and their host clusters have similar X-ray luminosities. We report an increase in the size of the BCGs from intermediate to local redshift. However, we do not detect any variation in the Sersic shape parameter in both samples. These results prove to be robust since the observed tendencies are model independent. We also obtain significant correlations between some of the BCG parameters and the main properties of the host clusters. More luminous, larger, and centrally located BCGs are located in more massive and dominant galaxy clusters. These facts indicate that the host galaxy cluster has played an important role in the formation of their BCGs. We discuss the possible mechanisms that can explain the observed evolution of the structural parameters of the BCGs. We conclude that the main mechanisms that can explain the increase in size and the non-evolution in the Sersic shape parameter of the BCGs in the last 6 Gyr are feedback processes. This result disagrees with semi-analytical simulation results supporting the idea that merging processes are the main mechanism responsible for the evolution of the BCGs up until the present epoch.

Ascaso, B. [Department of Physics, University of California, Davis, One Shields Avenue, Davis, CA 95616 (United States); Aguerri, J. A. L.; Varela, J.; Cava, A. [Instituto de Astrofisica de Canarias, C/VIa Lactea s/n, 38200 La Laguna, Tenerife (Spain); Bettoni, D. [INAF-Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, 35122 Padova (Italy); Moles, M. [Instituto de Astrofisica de Andalucia-CSIC, Glorieta de la Astronomia s/n, 18008 Granada (Spain); D'Onofrio, M. [Dip. Astronomia, Universita di Padova, Vicolo Osservatorio 2, 35122 Padova (Italy)

2011-01-10

399

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

400

Study of effect of process parameters on titanium sheet metal bending using Nd: YAG laser  

NASA Astrophysics Data System (ADS)

Laser Bending is a new non-contact technique of forming sheet-metal components. This method has been extended to bend Titanium components in industry. In Titanium laser bending process serious issues such as oxide film formation and subsequent deleterious changes in material properties are encountered. This paper investigates methods to minimize oxidation with minimal change in bending results for Grade-2 Titanium. Inert gas shielding is used as a means of reducing oxidation. Different gas flow conditions, nozzle positions and inert gas combinations are used to enhance the bend quality and bend angle. These process changes lead to final bending angle increase and decrease in width of Heat Affected Zone (HAZ), section thickness of sheet at HAZ and surface hardness. Also as Grade-2 Titanium is highly reflective, different coatings have been used to improve the absorption of laser beam which resulted in further increase in bending angle.

Shidid, D. P.; Gollo, M. Hoseinpour; Brandt, M.; Mahdavian, M.

2013-04-01

401

Effects of processed parameters on the magnetic performance of a powder magnetic core  

NASA Astrophysics Data System (ADS)

The goal of this study is to develop a high magnetic flux density and low iron loss powder magnetic core with insulated layer coating on pure iron powders of varying sizes. After processing the phosphate treatment, the insulated layer Zn3(PO4)2 was coated onto the iron powder surface. It not only maintained the magnetic flux density of pure iron, but also enhanced the electrical resistivity of the magnetic core by reducing eddy current loss, which allowed a wider frequency range. In addition, the annealing treatment after the compression process raised the magnetic flux density of the magnetic core; however, an annealing temperature above 200 °C caused the binder to decompose, resulting in decreased electrical resistivity. Experimental results indicate that the best magnetic performances were achieved with a powder magnetic core of fine and coarse iron powder proportion of 2:1, phosphate treatment of 90 s, and an annealing temperature of 200 °C.

Xie, Ding-Zhou; Lin, Kuan-Hong; Lin, Shun-Tian

2014-03-01

402

Effect of Titanium Carbide particle addition in the aluminium composite on EDM process parameters  

Microsoft Academic Search

Machining of hard materials such as metal matrix composites (Al\\/TiC) to a high degree of accuracy and surface finish is difficult. Electrical discharge machining (EDM) is an important process for machining difficult-to-machine materials like metal matrix composites. EDM is an effective tool in shaping such difficult-to-machine materials. The objective of this work is to investigate the effect of current (C),

Velusamy Senthilkumar; Bidwai Uday Omprakash

2011-01-01

403

Optimization of Process Parameters of Chemical Bath Deposition of Cd1-XZnxS Thin Film  

Microsoft Academic Search

Chemical bath deposition of Cd1-xZnxS is achieved by the slow release of sulphide ions and the controlled release of cadmium and zinc ions in solution. However the difference in the solubility products of CdS and ZnS by several orders usually narrows the chalcogenide operating window, this coupled with the difference in their stability constant makes Cd1-xZnxS CBD process very difficult.

Kasim Uthman ISAH; Narayanan HARIHARAN; Anthony OBERAFO

404

Power parameters of the impact pressing process of an incompact wire stock  

Microsoft Academic Search

A mathematical model of the impact pressing process of an incompact wire stock via a conical matrix has been proposed. It\\u000a is based on a superposition of solutions for two problems: pressing of powder material in a cylindrical press mold and impact\\u000a pressing of an incompressible material. The model allows one to determine the minimum velocity of the instrument proper

A. P. Polyakov

2007-01-01

405

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

Microsoft Academic Search

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

Alain Schorderet; Emmanuel Deghilage; Kossi Agbeviade

2011-01-01

406

Modeling and Optimization of Process Parameters for Defect Toleranced Drilling of GFRP Composites  

Microsoft Academic Search

Drilling is a frequently practiced machining process for fiber-reinforced plastics (FRP) in industry owing to the need for component assembly in mechanical structures. Drilling experiments are performed on a (0\\/±45\\/90)2s 3-mm-thick glass fiber-reinforced laminate using 4-, 6- and 8-mm-diameter HSS drills. The machining response of the quasi-isotropic laminate was studied by monitoring the thrust and torque. The performance of the

S. Arul; D. Samuel Raj; L. Vijayaraghavan; S. K. Malhotra; R. Krishnamurthy

2006-01-01

407

Optimization of photo-Fenton process parameters on carbofuran degradation using central composite design  

Microsoft Academic Search

Carbofuran, one of the most toxic and biorefractory carbamate compounds, is widely used in insecticides in Taiwan (9–18% of total insecticides production per year). In the present study, a central composite design experiment was used to study the effect of photo-Fenton treatment on carbofuran solution and to optimize the process variables such as carbofuran concentration (1–100 mg L), H2O2 dosage

Li A. LU; Ying S. Ma; Achlesh Daverey; Jih G. Lin

2012-01-01

408

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

409

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

410

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

411

Science Education and Outreach: Forging a Path to the Future ASP Conference Series, Vol. 431  

E-print Network

Science Education and Outreach: Forging a Path to the Future ASP Conference Series, Vol. 431 Guevara,3 and Scott Randol3 1Space Sciences Laboratory, University of California, Berkeley, 7 Gauss Way, Berkeley, CA 94720-7450, USA 2Center for Science Education, Space Sciences Laboratory, University

Fillingim, Matthew

412

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

413

Forging a Pedagogy of Teacher Education: The Challenges of Moving from Classroom Teacher to Teacher Educator  

ERIC Educational Resources Information Center

This paper reports an investigation of the challenges a former classroom teacher encountered when compelled by experiences as a supervisor of student teachers to forge a distinct pedagogy of teacher education. A qualitative self-study methodology was used to identify and examine the competing tensions that surfaced as the author made the…

Ritter, Jason K.

2007-01-01

414

Mapping Global Consciousness: Portuguese Imperialism and the Forging of Modern Global Sensibilities  

Microsoft Academic Search

This article concerns the Portuguese forging of globalization, globality, and forms of global consciousness in the early modern period. In the now voluminous Anglophone literature on globalization, depiction of the Portuguese contribution to such matters is generally muted, if not ignored altogether, in favour of accounts of Columbus's famous voyage and the Spanish conquest of the Americas as the constitutive

David Inglis

2011-01-01

415

Td 4: Optimisation avec contraintes Paul Dorbec, Cedric Bentz, David Forge  

E-print Network

Td 4: Optimisation avec contraintes Paul Dorbec, C´edric Bentz, David Forge 2 juin 2009 1 Conditions de Kuhn et Tucker Nous cherchons `a minimiser la fonction f : R2 - R (x1, x2) - x3 1 - x2 2 sc. g1

Dorbec, Paul

416

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

417

A comparative evaluation of the theoretical failure criteria for workability in cold forging  

Microsoft Academic Search

This paper evaluates various theoretical failure criteria pertaining to workability in cold forging reported in the published literature for their reliability and sensitivity in predicting the occurrence of ductile fracture in metalworking. Finite element (FE) simulation of the published upsetting experiments on cylindrical test specimens was performed to determine the threshold values attained by various criteria at the fractured locations,

A Venugopal Rao; N Ramakrishnan; R Krishna kumar

2003-01-01

418

Effect of friction on barrelling in square billets of aluminium during cold upset forging  

Microsoft Academic Search

This work deals with the generation of data on cold upset forging of square billets of annealed aluminium under different frictional conditions. Three different aspect ratios and constant load levels were considered for the above said upsetting experiment. The calculations were made on the assumption that the curvature of the barrel followed the geometry of circular arc. The measured radius

K. Manisekar; R. Narayanasamy; S. Malayappan

2006-01-01

419

Tool life in cold forging – an example of design improvement to increase service life  

Microsoft Academic Search

The production cost for cold forgings depends significantly on the tool life. This paper summarizes an investigation of different alternatives to improve the life of a tungsten carbide insert used in a cold forming operation performed on an automatic cold header. These alternatives were as follows: (a) double tapered insert, (b) split insert design, and (c) change of insert material.

Victor Vazquez; Daniel Hannan; Taylan Altan

2000-01-01

420

Numerical modelling of cyclic plasticity and fatigue damage in cold-forging tools  

Microsoft Academic Search

Industrial cold-forging tools with complex geometry are very likely to be exposed to local plastic deformation near stress concentrating details. The accumulation of plastic deformation resulting from the cyclic loading conditions leads to fatigue damage and eventually to generation of a crack in the surface of the die. To study the effect of die prestressing on fatigue damage development, a

Thomas Ørts Pedersen

2000-01-01

421

Improvement of tool life in cold forging by locally optimized surfaces  

Microsoft Academic Search

Cold forging tools are exposed to extremely high loads. Depending on the most critical combination of the dominant factors characterizing the load which can be different even within the same tool, different damaging mechanisms will be initiated at least one of which is finally limiting tool life by either wear or fatigue. Since these failure mechanisms are mostly initiated on

K. Wagner; A. Putz; U. Engel

2006-01-01

422

Development of a flexible tool system for small quantity production in cold forging  

Microsoft Academic Search

Among the technical tasks that have to be fulfilled in order to carry out economically feasible small quantity production in cold forging, low tool costs, short design lead time and quick tool change systems are some of the most important issues. The present paper describes a flexible tool system, which makes it possible to operate with the eight basic cold

L. S. Nielsen; S. Lassen; C. B. Andersen; J. Grønbæk; N. Bay

1997-01-01

423

A Life Study of Ausforged, Standard Forged and Standard Machined AISI M-50 Spur Gears  

NASA Technical Reports Server (NTRS)

Tests were conducted at 350 K (170 F) with three groups of 8.9 cm (3.5 in.) pitch diameter spur gears made of vacuum induction melted (VIM) consumable-electrode vacuum-arc melted (VAR), AISI M-50 steel and one group of vacuum-arc remelted (VAR) AISI 9310 steel. The pitting fatigue life of the standard forged and ausforged gears was approximately five times that of the VAR AISI 9310 gears and ten times that of the bending fatigue life of the standard machined VIM-VAR AISI M-50 gears run under identical conditions. There was a slight decrease in the 10-percent life of the ausforged gears from that for the standard forged gears, but the difference is not statistically significant. The standard machined gears failed primarily by gear tooth fracture while the forged and ausforged VIM-VAR AISI M-50 and the VAR AISI 9310 gears failed primarily by surface pitting fatigue. The ausforged gears had a slightly greater tendency to fail by tooth fracture than the standard forged gears.

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

1975-01-01

424

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

425

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.

426

Determination of the initial billet geometry for a forged product using neural networks  

Microsoft Academic Search

In the paper, the authors propose a new technique to determine the initial billet geometry for the forged products using a function approximation in neural networks. A three-layer neural network is used and the back-propagation algorithm is employed to train the network. The billet geometry is determined by applying the ability of the function approximation of neural networks to determine

D. J Kim; B. M Kim; J. C Choi

1997-01-01

427

Interior of shop, detail of 8,000 pound forging hammer, looking ...  

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

Interior of shop, detail of 8,000 pound forging hammer, looking west - Bethlehem Steel Corporation, South Bethlehem Works, Tool Steel-Electric Furnace Shop, Along Lehigh River, North of Fourth Street, West of Minsi Trail Bridge, Bethlehem, Northampton County, PA

428

Interior of shop, detail of 8,000 pound forging hammer (this ...  

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

Interior of shop, detail of 8,000 pound forging hammer (this hammer was probably manufactured the Chambersburg Engineering Company of Chambersburg, Pennsylvania), looking east - Bethlehem Steel Corporation, South Bethlehem Works, Tool Steel-Electric Furnace Shop, Along Lehigh River, North of Fourth Street, West of Minsi Trail Bridge, Bethlehem, Northampton County, PA

429

Low cost forged Y-pattern valves control hot corrosive/erosive gases  

SciTech Connect

The Morgantown Energy Technology Center in Morgantown, West Virginia is a research facility of the US Department of Energy (DOE) that does research on fossil fuels utilization and conversion to provide improved and environmentally acceptable energy sources. One area of investigation in the Morgantown facility is the use of gaseous fuels derived from coal from fluidized-bed and fixed-bed gasification technologies. The corrosive and slightly erosive gases and vapors at about 1000F and from 100 to 300 psi are treated in an experimental desulfurization unit to produce fuel gas with greatly enhanced environmental characteristics. The valves in use were constructed of Type 347 stainless steel, a stabilized version of 316 SS, and cost about $6000 for the 2'' size and about $4000 for the 1'' size. Despite the high cost, the valve sometimes became difficult or impossible to operate due to metal failures. The Technology Center had a number of new Class 1500 Y-pattern (angle-style) globe valves in inventory. The control valve body and bonnet are forged chrome moly steel (ASTM-H182-F22), the stem assembly is a 13% chrome alloy with an erosion resistant hard faced disc, and the seat ring is a cobalt-base alloy fused in place as an integral part of the body. Stem packing as an either wire inserted molded asbestos or Grafoil flexible graphite. The Y-pattern globe valves in 1 and 2'' sizes, which were judged potentially suitable and on hand, were installed in the experimental desulfization unit as well as in the connecting hot gas piping system to a new coal gasification process. The Class 1500 Y-pattern valves have provided reliable control of the hot corrosive and erosive gas streams with very little maintenance.

Gaines, A.

1987-06-01

430

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

431

The removal of the trivalent chromium from the leather tannery wastewater: the optimisation of the electro-coagulation process parameters.  

PubMed

The capacity of the electro-coagulation (EC) process for the treatment of the wastewater containing Cr3+, resulting from a leather tannery industry placed in Medellin (Colombia), was evaluated. In order to assess the effect of some parameters, such as: the electrode type (Al and/or Fe), the distance between electrodes, the current density, the stirring velocity, and the initial Cr3+ concentration on its efficiency of removal (%RCr+3), a multifactorial experimental design was used. The %RCr3+ was defined as the response variable for the statistical analysis. In order to optimise the operational values for the chosen parameters, the response surface method (RSM) was applied. Additionally, the Biological Oxygen Demand (BOD5), the Chemical Oxygen Demand (COD), and the Total Organic Carbon (TOC) were monitored during the EC process. The electrodes made of aluminium appeared to be the most effective in the chromium removal from the wastewater under study. At pH equal to 4.52 and at 28°C, the optimal conditions of Cr3+ removal using the EC process were found, as follows: the initial Cr3+ concentration=3,596 mg/L, the electrode gap=0.5 cm, the stirring velocity=382.3 rpm, and the current density=57.87 mA/cm2. At those conditions, it was possible to reach 99.76% of Cr3+ removal, and 64% and 61% of mineralisation (TOC) and COD removal, respectively. A kinetic analysis was performed in order to verify the response capacity of the EC process at optimised parameter values. PMID:21278458

GilPavas, E; Dobrosz-Gómez, I; Gómez-García, M Á

2011-01-01

432

Robust estimation of the parameters of a disturbed non-stationary Gaussian process  

E-print Network

A typical problem in the detection of the gravitational waves in the data of gravitational antennas is the non-stationarity of the Gaussian noise (and so the varying sensitivity) and the presence of big impulsive disturbances. In such conditions the estimation of the standard deviation of the Gaussian process done with a classical estimator applied after a "rough" cleaning of the big pulses often gives poor results. We propose a method based on a matched filter applied to an AR histogram of the absolute value of the data

Sergio Frasca; Pia Astone

2009-05-15

433

A study of the properties of functional parameters of spatial processes for spectral estimation  

E-print Network

2p(. ) as 2 i(si ? sj) = var(Z(si) ? Z(sj)). Similarly, define the covariogram C(. ) as C(si ? sj) = cov(Z(si), Z(sj)). We then have the relationship between the variogram and covariogram 2p(h) = 2(C(0) ? C(h)) for h E R . These functions... want to simulate a realization of a process Z(. ) at location s and that Z(. ) has covariogram C(. ). We can also assume that under fairly general conditions, f+ ~C(h) ~dh ( oo. Thus, there exists a function g(. ) such that r+oo C(h) = J g(a) cos...

Fayolle, Jean-Michel

1992-01-01

434

Numerical methods for improving sensitivity analysis and parameter estimation of virus transport simulated using sorptive-reactive processes  

USGS Publications Warehouse

Using one- and two-dimensional homogeneous simulations, this paper addresses challenges associated with sensitivity analysis and parameter estimation for virus transport simulated using sorptive-reactive processes. Head, flow, and conservative- and virus-transport observations are considered. The paper examines the use of (1) observed-value weighting, (2) breakthrough-curve temporal moment observations, and (3) the significance of changes in the transport time-step size. The results suggest that (1) sensitivities using observed-value weighting are more susceptible to numerical solution variability, (2) temporal moments of the breakthrough curve are a more robust measure of sensitivity than individual conservative-transport observations, and (3) the transport-simulation time step size is more important than the inactivation rate in solution and about as important as at least two other parameters, reflecting the ease with which results can be influenced by numerical issues. The approach presented allows more accurate evaluation of the information provided by observations for estimation of parameters and generally improves the potential for reasonable parameter-estimation results. ?? 2004 Elsevier B.V. All rights reserved.

Barth, G.; Hill, M.C.

2005-01-01

435

Effect of Process Parameters on Particle Removal Efficiency in Poly(vinyl alcohol) Brush Scrubber Cleaning  

NASA Astrophysics Data System (ADS)

Wafer cleaning is one of the most critical processes in the semiconductor device manufacturing. Poly(vinyl alcohol) (PVA) brush scrubber cleaning is much attractive when compared with traditional wet-batch cleaning which causes the cross-contamination among the wafers in a bath and environmental issues with huge amount of chemical and deionized water (DIW) usages. The mechanical forces generated from PVA brush contact can remove the particles on a wafer surface under low concentration of chemical solution without cross-contamination. In this research, we monitored the change of the dynamic forces including normal and friction force generated by PVA brush contacts during cleaning process, and also investigated the effects of scrubbing conditions of PVA brush overlap and velocity, and the surface tension (low- or high-hydrophilic) of the wafer on the particle removal efficiency. The results show that the driving mechanism to remove the particle on a wafer surface can be changed by the PVA brush overlap and velocity condition such as the hydrodynamic drag force in the brush soft contact condition and friction force in the brush hard contact condition. The particle removal efficiency is higher under the low-hydrophilic surface having a low surface tension compared to high-hydrophilic surface.

An, Joonho; Lee, Hyunseop; Kim, Hyoungjae; Jeong, Haedo

2012-02-01

436

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

437

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

438

On psychobiology in psychoanalysis - salivary cortisol and secretory IgA as psychoanalytic process parameters  

PubMed Central

This study investigates the psychobiological impact of psychoanalysis in its four-hour setting. During a period of five weeks, 20 subsequent hours of psychoanalysis were evaluated, involving two patients and their analysts. Before and after each session, saliva samples were taken and analysed for cortisol (sCortisol) and secretory immunoglobuline A (sIgA). Four time-series (n=80 observations) resulted and were evaluated by "Pooled Time Series Analysis" (PTSA) for significant level changes and setting-mediated rhythms. Over all sessions, sCortisol levels were reduced and sIgA secretion augmented parallel to the analytic work. In one analytic dyad a significant rhythm within the four-hour setting was observed with an increase of sCortisol in sessions 2 and 3 of the week. Psychoanalysis may, therefore, have some psychobiological impact on patients and analysts alike and may modulate immunological and endocrinological processes. PMID:19742067

Euler, Sebastian; Schimpf, Heinrich; Hennig, Jürgen; Brosig, Burkhard

2005-01-01

439

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

440

Taurine improves the wound healing process in cutaneous leishmaniasis in mice model, based on stereological parameters  

PubMed Central

Background: Cutaneous Leishmaniasis is a self-limiting disease caused by protozoan parasites of the genus Leishmania, which affects the skin with full-thickness wounds, which are prone to scar formation even after treatment. Taurine (Tu) is one of the most abundant amino acids that has antioxidant and anti-inflammatory effects, which play an important role in the process of wound healing. Herein, we have investigated the effects of Tu on cutaneous Leishmaniasis wounds and L. major promastigotes. Materials and Methods: Eighteen mice were induced with Leishmaniasis wounds (with L. Major) on the base of their tails and divided into three groups, T1: Treated with Tu injection, T2: Treated with Tu gel, and C: No treatment. Treatments were carried out every 24 hours for 21 days. The volume densities of the collagen bundles and vessels, vessel's length density and diameter, and fibroblast populations were estimated by stereological methods. Flow cytometry was used in order to investigate the direct Tu effect on parasites. The Mann-Whitney U test was used and P ? 0.05 was considered to be statistically significant. Results: The numerical density of the fibroblasts, volume density of the collagen bundles, and length densities of the vessels in groups T1 and T2 were significantly higher than in group C (P < 0.05). The fibroblast numerical density of group T1 was higher than that of group T2 (P = 0.02). Incidentally, Tu had no direct effect on L. major parasites according to the flow cytometry analysis. Conclusion: Tu showed the ability to improve the wound healing process and tissue regeneration although it had no direct anti-leishmaniasis effect. PMID:25337534

Ashkani-Esfahani, Soheil; Zarifi, Fariba; Asgari, Qasem; Samadnejad, Asal Zargari; Rafiee, Shima; Noorafshan, Ali

2014-01-01

441

Multiobjective Optimization of Atmospheric Plasma Spray Process Parameters to Deposit Yttria-Stabilized Zirconia Coatings Using Response Surface Methodology  

NASA Astrophysics Data System (ADS)

Atmospheric plasma spraying is used extensively to make Thermal Barrier Coatings of 7-8% yttria-stabilized zirconia powders. The main problem faced in the manufacture of yttria-stabilized zirconia coatings by the atmospheric plasma spraying process is the selection of the optimum combination of input variables for achieving the required qualities of coating. This problem can be solved by the development of empirical relationships between the process parameters (input power, primary gas flow rate, stand-off distance, powder feed rate, and carrier gas flow rate) and the coating quality characteristics (deposition efficiency, tensile bond strength, lap shear bond strength, porosity, and hardness) through effective and strategic planning and the execution of experiments by response surface methodology. This article highlights the use of response surface methodology by designing a five-factor five-level central composite rotatable design matrix with full replication for planning, conduction, execution, and development of empirical relationships. Further, response surface methodology was used for the selection of optimum process parameters to achieve desired quality of yttria-stabilized zirconia coating deposits.

Ramachandran, C. S.; Balasubramanian, V.; Ananthapadmanabhan, P. V.

2011-03-01

442

Investigation into the effect of overlap factors and process parameters on surface roughness and machined depth during micro-turning process with Nd:YAG laser  

NASA Astrophysics Data System (ADS)

One of the emerging laser material processing technologies to process cylindrical shaped materials is the laser micro-turning process. This process is used to machine micro-turned groove or surface on the difficult-to-process materials for a specific length of turn along its axis. The present experimental study investigates the laser micro-turning operation of a cylindrical shaped aluminum oxide (Al2O3) ceramic to explore the effect of successive spot overlap and circumferential overlap on the surface roughness (Ra) criterion. Moreover, depth of machining has also been studied by varying various process parameters such as pulse frequency, workpiece rotating speed and laser beam average power. Various amounts of spot overlap have been accomplished by different combined settings of related parameters i.e. workpiece rotating speed and pulse frequency. In contrast, various circumferential overlap between successive rotational scan widths have been achieved by varying the rotational speed and also axial feed rate of the workpiece. Surface roughness (Ra) and machined depth have been measured as output response for machining at various parametric combinations. Analyses have been made through different plots of surface roughness (Ra) and machined depth to study the influence of these overlaps and different process parameters. The experimental results revealed that surface roughness decreases with the increase of both the overlap factors. It is observed from the results that with the increase in circumferential overlap, roughness of the machined surface decreases for each workpiece rotating speed setting. Further, wide spot crater is achieved at a higher value of average power. Minimum surface roughness is achieved as 5.25 µm at average power 10 W, pulse frequency 3000 Hz, workpiece rotating speed 400 rpm and Y feed rate 0.3 mm/s. The achieved machined depth is high at a low speed of rotation and pulse frequency settings. With the increase of average power of laser beam, the machined depth is found to increase linearly. The maximum micro-turning depth is achieved as 0.146 mm at parametric combination of average power of 10 W, pulse frequency of 3000 Hz, workpiece rotating speed of 400 rpm and Y feed rate of 0.3 mm/s.

Kibria, G.; Doloi, B.; Bhattacharyya, B.

2014-08-01

443

The Relevance Of The Preform Design In Coining Processes Of Cupronickel Alloy  

SciTech Connect

Coining is a forging process in which a metallic disk, characterized by a low volume-surface ratio, is deformed with the aim to impress 3D images on its three surfaces. Due to the large production volumes and, at the same time, to the high quality standards required to the final products in terms of final dimensions, tolerances and surface finishing, such closed-die, cold forging process requires a careful evaluation and choice of the proper operative parameters. In particular, along with technological parameters as the die velocity, die stroke and lubrication, which, in turn, contribute to affect the pressure values on the die surfaces, and thus the press choice, geometrical parameters as the side ring inner diameter and, above all, the preform geometry, strongly affect the quality of the obtained parts. In this paper, a 3D FEM model for coining processes is proposed, that is Lagrangian implicit, rigid-viscoplastic. The relationships between the obtained geometry and the starting preform shape is numerically investigated, allowing, through the analysis of the effective stresses, strain, and strain rate on the coin, as well as of the loads on the dies, to highlight the significance of the perform design in order to obtain a final product that satisfies the strict geometrical tolerances required. It is found that the best results on the final part are obtained with chamfered preform geometries, though larger values of force on the dies are observed.

Buffa, G.; Fratini, L.; Micari, F. [Dipartimento di Tecnologia Meccanica, Produzione e Ingegneria Gestionale, University of Palermo, Viale delle Scienze 90128 Palermo (Italy)

2007-05-17

444

The Relevance Of The Preform Design In Coining Processes Of Cupronickel Alloy  

NASA Astrophysics Data System (ADS)

Coining is a forging process in which a metallic disk, characterized by a low volume-surface ratio, is deformed with the aim to impress 3D images on its three surfaces. Due to the large production volumes and, at the same time, to the high quality standards required to the final products in terms of final dimensions, tolerances and surface finishing, such closed-die, cold forging process requires a careful evaluation and choice of the proper operative parameters. In particular, along with technological parameters as the die velocity, die stroke and lubrication, which, in turn, contribute to affect the pressure values on the die surfaces, and thus the press choice, geometrical parameters as the side ring inner diameter and, above all, the preform geometry, strongly affect the quality of the obtained parts. In this paper, a 3D FEM model for coining processes is proposed, that is Lagrangian implicit, rigid-viscoplastic. The relationships between the obtained geometry and the starting preform shape is numerically investigated, allowing, through the analysis of the effective stresses, strain, and strain rate on the coin, as well as of the loads on the dies, to highlight the significance of the perform design in order to obtain a final product that satisfies the strict geometrical tolerances required. It is found that the best results on the final part are obtained with chamfered preform geometries, though larger values of force on the dies are observed.

Buffa, G.; Fratini, L.; Micari, F.

2007-05-01

445

Floating basaltic lava balloons - constrains on the eruptive process based on morphologic parameters  

NASA Astrophysics Data System (ADS)

The 1998-2001 submarine Serreta eruption brought to science a new challenge. This eruption took place offshore of Terceira Island (Azores), on the so-called Serreta Submarine Ridge, corresponding to a basaltic fissure zone with alkaline volcanism, within a tectonic setting controlled by an hyper-slow spreading rift (the Terceira Rift). The inferred eruptive centers are alignment along a NE-SW direction over an area with depths ranging from 300 to more than 1000 meters. The most remarkable products of this eruption, were large basaltic balloons observed floating at the sea surface. Those balloons, designated as Lava Balloons, are spherical to ellipsoidal structures, ranging from 0.4 up to about 3 m in length, consisting of a thin lava shell enveloping a closed hollow interior, normally formed by a single large vesicle, or a few large convoluted vesicles, that grants an overall density below water density. The cross section of the lava shell usually ranges between 3 and 8 cm and has a distinct layered structure, with different layers defined by different vesicularity, bubble number density and crystal content. The outermost layer is characterized by very small vesicles and high bubble number density whereas the innermost layer has larger vesicles, lower bubble number density and higher crystal content. These observations indicate that the rapidly quenched outer layer preserved the original small vesicles present on the magma at the time of the balloon's formation while the inner layer continued to evolve, producing higher crystal content and allowing time for the expansion of vesicles inward and their efficient coalescence. The outer surface of the balloons exhibits patches of very smooth glassy surface and areas with striation and grooves resulting from small scale fluidal deformation. These surface textures are interpreted as the result of the extrusion process and were produced in a similar manner to the striation found on subaerial toothpaste lavas. Such characteristics are indicative that the outer surface of the balloon quenched as it was being extruded and preserved the scars of a squeeze-up process. On this outer surface, several superficial expansion cracks reveal that after its generation the balloon endured some expansion before reaching the sea surface, most likely due to hydrostatic decompression during its rise. The entire shell of the balloons shows bends and folds resulting from large ductile deformations, also suggesting an origin as an effusive process of squeezing-up a large vesicle through a fissure in a thin lava crust, similarly to the extrusion of a gas filled lava toe. Actually, the volume of the lava shell is not enough to produce all the gas in the balloons interior. More likely, at an earlier stage, degassing of magma as an open system allowed gas to segregate and accumulate to form large vesicles. The development of very large vesicles would be favored by a ponding system such as a lava lake.

Pacheco, J. M.; Zanon, V.; Kueppers, U.

2011-12-01

446

High-intensity pulsed electric fields processing parameters affecting polyphenoloxidase activity of strawberry juice.  

PubMed

High-intensity pulsed electric fields (HIPEF) were applied to strawberry juice to study the feasibility of inactivating polyphenoloxidase (PPO). Response surface methodology was used to evaluate the effect of HIPEF processing, in which total treatment time (1000 to 2000 ?s), pulse frequency (50 to 250 Hz), pulse width (1.0 to 7.0 ?s), and polarity (monopolar or bipolar) were the controlled variables at a constant electric field of 35 kV/cm. The proposed 2nd-order response functions were accurate enough to fit experimental results. Strawberry juice PPO was strongly reduced within the range of assayed conditions. HIPEF treatments were more effective in bipolar than in monopolar mode in inactivating PPO. Treatments of longer duration resulted in reductions of the enzyme activity. Moreover, it was feasible to minimize residual PPO activity (down to 2.5%) by selecting bipolar treatments at frequencies higher than 229 Hz and pulse widths between 3.23 and 4.23 ?s for a constant total treatment time of 2000 ?s. PMID:21535531

Aguiló-Aguayo, Ingrid; Soliva-Fortuny, Robert; Martín-Belloso, Olga

2010-09-01

447

Gelatin-GAG electrospun nanofibrous scaffold for skin tissue engineering: Fabrication and modeling of process parameters.  

PubMed

Electrospinning is a very useful technique for producing polymeric nanofibers by applying electrostatic forces. In this study, fabrication of novel gelatin/GAG nanofibrous mats and also the optimization of electrospinning process using response surface methodology were reported. At optimization section, gelatin/GAG blend ratio, applied voltage and feeding rate, their individual and interaction effects on the mean fiber diameter (MFD) and standard deviation of fiber diameter (SDF) were investigated. The obtained model for MFD has a quadratic relationship with gelatin/GAG blend ratio, applied voltage and feeding rate. The interactions of blend ratio and applied voltage and also applied voltage and flow rate were found significant but the interactions of blend ratio and flow rate were ignored. The optimum condition for gelatin/GAG electrospinning was also introduced using the model obtained in this study. The potential use of optimized electrospun mat in skin tissue engineering was evaluated using culturing of human dermal fibroblast cells (HDF). The SEM micrographs of HDF cells on the nanofibrous structure show that fibroblast cells can highly attach, grow and populate on the fabricated scaffold surface. The electrospun gelatin/GAG nanofibrous mats have a potential for using as scaffold for skin, cartilage and cornea tissue engineering. PMID:25579974

Pezeshki-Modaress, Mohamad; Mirzadeh, Hamid; Zandi, Mojgan

2015-03-01

448

Effect of inlet and outlet flow conditions on natural gas parameters in supersonic separation process.  

PubMed

A supersonic separator has been introduced to remove water vapour from natural gas. The mechanisms of the upstream and downstream influences are not well understood for various flow conditions from the wellhead and the back pipelines. We used a computational model to investigate the effect of the inlet and outlet flow conditions on the supersonic separation process. We found that the shock wave was sensitive to the inlet or back pressure compared to the inlet temperature. The shock position shifted forward with a higher inlet or back pressure. It indicated that an increasing inlet pressure declined the pressure recovery capacity. Furthermore, the shock wave moved out of the diffuser when the ratio of the back pressure to the inlet one was greater than 0.75, in which the state of the low pressure and temperature was destroyed, resulting in the re-evaporation of the condensed liquids. Natural gas would be the subsonic flows in the whole supersonic separator, if the mass flow rate was less than the design value, and it could not reach the low pressure and temperature for the condensation and separation of the water vapor. These results suggested a guidance mechanism for natural gas supersonic separation in various flow conditions. PMID:25338207

Yang, Yan; Wen, Chuang; Wang, Shuli; Feng, Yuqing

2014-01-01

449

Effect of Inlet and Outlet Flow Conditions on Natural Gas Parameters in Supersonic Separation Process  

PubMed Central

A supersonic separator has been introduced to remove water vapour from natural gas. The mechanisms of the upstream and downstream influences are not well understood for various flow conditions from the wellhead and the back pipelines. We used a computational model to investigate the effect of the inlet and outlet flow conditions on the supersonic separation process. We found that the shock wave was sensitive to the inlet or back pressure compared to the inlet temperature. The shock position shifted forward with a higher inlet or back pressure. It indicated that an increasing inlet pressure declined the pressure recovery capacity. Furthermore, the shock wave moved out of the diffuser when the ratio of the back pressure to the inlet one was greater than 0.75, in which the state of the low pressure and temperature was destroyed, resulting in the re-evaporation of the condensed liquids. Natural gas would be the subsonic flows in the whole supersonic separator, if the mass flow rate was less than the design value, and it could not reach the low pressure and temperature for the condensation and separation of the water vapor. These results suggested a guidance mechanism for natural gas supersonic separation in various flow conditions. PMID:25338207

Yang, Yan; Wen, Chuang; Wang, Shuli; Feng, Yuqing

2014-01-01

450

Effects of selected process parameters on the morphology of poly(ethylene terephthalate) preforms and bottles  

SciTech Connect

Small-angle X-ray scattering (SAXS) studies and polarized optical microscopy were undertaken to explore possible morphological explanations for the poor mechanical strength in the petaloid bases of poly(ethylene terephthalate) bottles. With a standard commercial production line, one set of injection-molded preforms was overpacked by 1.1 wt % to investigate the effect on the molecular morphology with respect to a set of control samples. Both sets of preforms showed highly crystalline and oriented areas corresponding to the injection gate region. The main body of the control preform was amorphous, and although the overpacked preform was essentially amorphous, there was some evidence for weak crystallinity. The SAXS patterns of the bottle petaloid base blown from the corresponding preforms produced similar SAXS patterns for overpacked and control bottle bases, indicating that the commercial process is robust at least to this degree of overpacking. Optical microscopy showed detailed crystalline features around the gate region and thin crystalline layers sandwiched between a quenched skin layer in direct contact with the cold mold walls and the main flow of material into the mold.

Hanley, Tracey; Sutton, David; Karatchevtseva, Inna; Cookson, David; Burford, Robert; Knott, Robert (ANSTO); (UC)

2008-10-03

451

Effect of Processing Parameters on Pore Structure and Thickness of Anodic Aluminum Oxide (AAO) Tubular Membranes.  

PubMed

Nanoporous anodic aluminum oxide (AAO) tubular membranes were fabricated from aluminum alloy tubes in sulfuric and oxalic acid electrolytes using a two-step anodization process. The membranes were investigated for characteristics such as pore size, interpore distance and thickness by varying applied voltage and electrolyte concentration. Morphology of the membranes was examined using light optical and scanning electron microscopy and characterized using ImageJ software. Results showed that membranes having narrow pore size and uniform pore distribution with parallel channel arrays were obtained. The pore sizes were ranging from 14 to 24 nm and the wall thicknesses as high as 76 microm. It was found that the pore size increased in direct proportion with the applied voltage and inversely with the electrolyte concentration while the interpore distance increased linearly with the applied voltage. It was also observed that increase in acid concentration increased tubular membrane wall thickness that improved mechanical handling. By using anodic alumina technology, robust ceramic tubes with uniformly distributed pore-structure and parallel nano-channels of lengths and sizes practical for industrial applications were reliably produced in quantity. PMID:19578471

Belwalkar, A; Grasing, E; Van Geertruyden, W; Huang, Z; Misiolek, W Z

2008-07-01

452

Optimization of laser beam welding process parameters to attain maximum tensile strength in AZ31B magnesium alloy  

NASA Astrophysics Data System (ADS)

An empirical relationship is developed to predict tensile strength of the laser beam welded AZ31B magnesium alloy by incorporating process parameters such as laser power, welding speed and focal position. The experiments were conducted based on a three factor, three level, central composite face centered design matrix with full replications technique. The empirical relationship can be used to predict the tensile strength of laser beam welded AZ31B magnesium alloy joints at 95% confidence level. The results indicate that the welding speed has the greatest influence on tensile strength, followed by laser power and focal position.

Padmanaban, G.; Balasubramanian, V.

2010-11-01

453

Development of Alloy and Superalloy Large Shafts by Friction Welding Process  

NASA Astrophysics Data System (ADS)

The aim of this study is to examine the process parameters of superalloy and alloy steel inertia welding using FE simulation and to evaluate the mechanical properties of a welded joint. FE simulation was carried out to optimize the inertia welding process parameters. Disk of rotor shaft and head of exhaust valve spindle are made by the hot closed die forging. Dissimilar inertia welding for large exhaust valve spindle manufacturing composed of the Nimonic 80 A valve head of 540 mm diameter and the SNCrW valve stem of 115 mm diameter, and for large rotor shaft manufacturing composed of the 310 mm diameter disk and the 140 mm diameter shaft were carried out with optimal process parameter conditions obtained simulation result. Inertia friction welded joint part was joined by inertia friction welder, MTI model 400. Mechanical and metallurgical properties of welded joints were evaluated by using microstructure, tensile, hardness and fatigue tests.

Jeong, H. S.; Cho, J. R.; Choi, S. K.; Oh, J. S.; Kim, E. N.

2010-06-01

454

Evaluation of Centrifugal Casting Process Parameters for In Situ Fabricated Functionally Gradient Fe-TiC Composite  

NASA Astrophysics Data System (ADS)

A gradient Fe-TiC composite was successfully produced via combination of in situ reaction with centrifugal casting techniques. Additionally, some of the effective parameters of the centrifugal casting process have been studied. Cast iron and ferrotitanium, which were used as raw materials, were melted using a high-frequency induction furnace coupled with centrifugal equipment. The microstructure and phase characterization of the fabricated composite was studied by scanning electron microscopy, optical microscopy, and X-ray diffraction. The results show that the production of a pearlite matrix composite reinforced by TiC particles is feasible. The distribution of TiC in the pearlitic matrix is completely uneven as a result of density difference between molten medium and TiC in the centrifugal casting process.

Rahimipour, Mohammad Reza; Sobhani, Manoochehr

2013-10-01

455

Effects of Processing Parameters on the Grain Refinement of Magnesium Alloy by Equal-Channel Angular Extrusion  

NASA Astrophysics Data System (ADS)

The Mg-3 pct Al-1 pct Zn (AZ31) alloy has been used as a model material for understanding the grain-refinement process of a Mg alloy fabricated by equal-channel angular extrusion (ECAE). The effects of ECAE processing parameters on grain refinement have also been studied; it was found that these effects are quite different from those for fcc metals. A multitemperature extrusion procedure has been developed, which can produce an ultrafine-grained AZ31 alloy having a grain size 0.37 ?m. For the AZ31 alloy, this ultrafine-grained alloy has a record high strength accompanied by reasonably good tensile ductility. The success of the development of this ECAE procedure proves that ECAE can offer a good opportunity for the development of high-strength Mg alloys.

Ding, S. X.; Chang, C. P.; Kao, P. W.

2009-02-01

456

Effect of Variation in Process Parameters on the Formation of Freckle in INCONEL 718 by Vacuum Arc Remelting  

NASA Astrophysics Data System (ADS)

In order to study the effect of variation in process parameters on the final ingot of INCONEL 718 during vacuum arc remelting, a 508-mm-diameter vacuum arc remelting (VAR) ingot of INCONEL 718 was produced under conditions of variation in electrode diameter and arc gap. It was sectioned and analyzed in the as-cast state. Freckle was found in the midradius and center regions when the electrode diameter and arc gap changed. The experimental results were discussed in relation to composition, current distribution, and fluid flow. Freckle formation was found to be associated with large changes in melting conditions probably resulting in significant perturbation of the fluid flow in the melt pool and mushy zone. Instability in the solidification process may contribute to the initiation and formation of freckle defects in INCONEL 718 ingot.

Wang, Xianhui; Ward, R. Mark; Jacobs, Mike H.; Barratt, Mark D.

2008-12-01

457

Standardization of process parameters for microwave assisted convective dehydration of ginger.  

PubMed

Ginger (Zingiber Officinale, Cv. Suprava) slices (4 mm thick) were dehydrated at 25°, 40°, 50° and 60 °C with three different microwave power levels, viz. 120, 240, and 360 W in microwave assisted convective dryer up to 0.07 g moisture/g dry solid to observe the feasibility of microwave assisted convective drying for ginger. The samples were also dried without application of microwaves (0 W) at the above air temperatures. The final product quality was compared in terms of rehydration characteristics, oleoresin and volatile oil contents, hardness, color and organoleptic quality. The maximum rehydration ratio of 3.86?±?0.06 was obtained at 50 °C without application of microwaves and was followed by 120 W-40 °C combination treatment (3.64?±?0.15). The minimum rehydration ratio was 2.34?±?0.20 for 360 W with 60 °C. The yield of oleoresin content was higher for 120 W as compared to other power levels, which ranged between 5.12?±?0.85% and 6.34?±?0.89%. The maximum retention of oleoresin was observed in case of 120 W-40 °C. The samples dried with microwave power level of 120 W also gave better yields of volatile oil as compared to other power levels. The best color was observed at 120 W-50 °C and 120 W-60 °C conditions with Hunter 'a' (redness) values at 0.50?±?0.03 and 0.35?±?0.03, respectively. The sensory analysis also indicated that drying at 120 W-50 °C and 240 W-50 °C combinations gave the most acceptable quality product. Drying ginger with 120 W-50 °C combination helped in a saving of 53% and 44% in drying time as compared to hot air drying at 50° and 60 °C, respectively. Drying at 240 W-50 °C also gave a reasonably acceptable quality product with a net saving of 91% and 89% in drying time as compared to hot air drying at 50° and 60 °C, respectively. However, on the basis of rehydration characteristics, the acceptable process conditions were hot air drying at 50° or 60 °C, or with the 120 W-40 °C combination. PMID:24741160

Mohanta, B; Dash, S K; Panda, M K; Sahoo, G R

2014-04-01

458

OREGON STATE UNIVERSITY (OSU) TRAINING RESEARCH ISOTOPE GENERAL ATOMICS (TRIGA) OVERPACK CLOSURE WELDING PROCESS PARAMETER DEVELOPMENT & QUALIFICATION  

SciTech Connect

Spent Nuclear Fuel (SNF) from the Oregon State University (OSU) TRIGA{reg_sign} Reactor is currently being stored in thirteen 55-gallon drums at the Hanford Site's low-level burial grounds. This fuel is soon to be retrieved from buried storage and packaged into new containers (overpacks) for interim storage at the Hanford Interim Storage Area (ISA). One of the key activities associated with this effort is final closure of the overpack by welding. The OSU fuel is placed into an overpack, a head inserted into the overpack top, and welded closed. Weld quality, for typical welded fabrication, is established through post-weld testing and nondestructive examination (NDE); however, in this case, once the SNF is placed into the overpack, routine testing and NDE are not feasible. An alternate approach is to develop and qualify the welding process/parameters, demonstrate beforehand that they produce the desired weld quality, and then verify parameter compliance during production welding. Fluor engineers have developed a Gas Tungsten Arc Welding (GTAW) technique and parameters, demonstrating that weld quality requirements for closure of packaged SNF overpacks are met, using this alternate approach. The following reviews the activities performed for this development and qualification effort.

CANNELL, G.R.

2006-09-11

459

Comparison of process parameter optimization using different designs in nanoemulsion-based formulation for transdermal delivery of fullerene  

PubMed Central

This research aims to formulate and to optimize a nanoemulsion-based formulation containing fullerene, an antioxidant, stabilized by a low amount of mixed surfactants using high shear and the ultrasonic emulsification method for transdermal delivery. Process parameters optimization of fullerene nanoemulsions was done by employing response surface methodology, which involved statistical multivariate analysis. Optimization of independent variables was investigated using experimental design based on Box–Behnken design and central composite rotatable design. An investigation on the effect of the homogenization rate (4,000–5,000 rpm), sonication amplitude (20%–60%), and sonication time (30–150 seconds) on the particle size, ?-potential, and viscosity of the colloidal systems was conducted. Under the optimum conditions, the central composite rotatable design model suggested the response variables for particle size, ?-potential, and viscosity of the fullerene nanoemulsion were 152.5 nm, ?52.6 mV, and 44.6 pascal seconds, respectively. In contrast, the Box–Behnken design model proposed that preparation under the optimum condition would produce nanoemulsion with particle size, ?-potential, and viscosity of 148.5 nm, ?55.2 mV, and 39.9 pascal seconds, respectively. The suggested process parameters to obtain optimum formulation by both models yielded actual response values similar to the predicted values with residual standard error of <2%. The optimum formulation showed more elastic and solid-like characteristics due to the existence of a large linear viscoelastic region. PMID:25258528

Ngan, Cheng Loong; Basri, Mahiran; Lye, Fui Fang; Fard Masoumi, Hamid Reza; Tripathy, Minaketan; Karjiban, Roghayeh Abedi; Abdul-Malek, Emilia

2014-01-01

460
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