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1

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

2

Large forging manufacturing process  

DOEpatents

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

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

2002-01-01

3

Forging process design for risk reduction  

Microsoft Academic Search

In this dissertation, forging process design has been investigated with the primary concern on risk reduction. Different forged components have been studied, especially those ones that could cause catastrophic loss if failure occurs. As an effective modeling methodology, finite element analysis is applied extensively in this work. Three examples, titanium compressor disk, superalloy turbine disk, and titanium hip prosthesis, have

Yongning Mao

2009-01-01

4

Microstructure optimization in design of forging processes  

Microsoft Academic Search

A new approach based on sensitivity analysis for optimizing the microstructure development during the forging processes is proposed in this work. The analytical sensitivities of the recrystallization volume fraction and dynamically recrystalized grain size with respect to the design variables are derived. The mean grain size in each finite element is introduced so that the complex recrystallization mechanics, such as

Zhenyan Gao; Ramana V. Grandhi

2000-01-01

5

Computer-aided process design and simulation for forging of turbine blades  

Microsoft Academic Search

Turbine and compressor blades for jet engines and gas turbines are forged from high-strength alloys and require close control of the process parameters. The design and manufacture of the dies require particular attention, for they impart their geometry to the final product. For precision forging, the die surface must be corrected for local elastic deflections and thermal shrinkage. Considering turbine

Nuri Akgerman; David J. Kasik

1974-01-01

6

Preform design of a generic turbine disk forging process  

Microsoft Academic Search

This work uses the finite-element-based inverse die contact tracking method to design the preform die shapes of a generic turbine-disk forging process. First, for a one-stage forging process, folding defects, extensive flash and underfill resulting from using an improper initial billet size are investigated. Trial forward simulations are performed while varying the height-to-diameter ratio and the optimal aspect ratio of

Guoqun Zhao; Zhenduo Zhao; Tonghai Wang; Ramana V. Grandhi

1998-01-01

7

Computer-aided modeling tools for forging process feasibility studies  

SciTech Connect

Equations were developed to express stress distributions for a variety of deformation configurations. Strain equations were developed as they apply to forged workpieces, as were strain rate equations. The flow stress equation was introduced. The shear criterion was established to minimize the amount of energy that deforming metal flow consumes. An equation was developed relating flash width and thickness using the concept of constant volume. Force equations were developed for lateral and converging flow. From these equations, the closed-die axisymmetric forging process was simulated in two cases: constant ram speed and constant strain rate. Fortran programs were developed for both cases. Software employed to present on-screen interactive graphics was FIGARO by MEGATEK. The feasibility of producing a particular part was studied by comparing net shape, near net shape, and conventional forging/machining methods. A near net shape design with some machining was recommended as most economical.

El-Gizawy, A.S. (Missouri Univ., Columbia, MO (United States). Dept. of Mechanical and Aerospace Engineering)

1992-03-01

8

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

NASA Astrophysics Data System (ADS)

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

Pepelnjak, Tomaž; Kuzman, Karl; Kokol, Anton

2011-05-01

9

Application of finite element method and artificial neural network to the die design of radial forging processes  

Microsoft Academic Search

This investigation adopts the finite element method (FEM) and the artificial neural network (ANN) to plan the radial forging of work-hardened materials to yield the optimal designed die. The process parameters considered herein are die corner radius (R), ring gap height (H), friction factor (m), work-hardening coefficient (n), gap between the billet and die (c) and the punch load (f).

Su-Hai Hsiang; Huey-Lin Ho

2004-01-01

10

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

11

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

Microsoft Academic Search

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

Liu Lili; Fan Lixia

2009-01-01

12

Sensitivity Analysis and Optimization Algorithms for 3D Forging Process Design  

NASA Astrophysics Data System (ADS)

This paper presents several approaches for preform shape optimization in 3D forging. The process simulation is carried out using the FORGE3® finite element software, and the optimization problem regards the shape of initial axisymmetrical preforms. Several objective functions are considered, like the forging energy, the forging force or a surface defect criterion. Both deterministic and stochastic optimization algorithms are tested for 3D applications. The deterministic approach uses the sensitivity analysis that provides the gradient of the objective function. It is obtained by the adjoint-state method and semi-analytical differentiation. The study of stochastic approaches aims at comparing genetic algorithms and evolution strategies. Numerical results show the feasibility of such approaches, i.e. the achieving of satisfactory solutions within a limited number of 3D simulations, less than fifty. For a more industrial problem, the forging of a gear, encouraging optimization results are obtained.

Do, T. T.; Fourment, L.; Laroussi, M.

2004-06-01

13

Design of a forging processing route for a gas turbine compressor disc in IMI 834  

NASA Astrophysics Data System (ADS)

A computer model for simulating the forging process capable of determining the mechanical and microstructural behavior of the material during processing is described. The model is based on a fully, thermally coupled, visco-plastic finite element approach for eight noded quadratic isoparametric elements. It is concluded that the use of the advanced forging model makes it possible to test and optimize die shapes and blow patterns before any metal is committed for use. This eliminates the need for iterative forging trials and drastically reduces development times.

Clark, G. S.

14

Prediction of Final Material State in Multi-Stage Forging Processes  

NASA Astrophysics Data System (ADS)

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

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

2004-06-01

15

Analysis and Optimization of the Radial Forging Process for Manufacturing Gun Barrels.  

National Technical Information Service (NTIS)

The objective of this Phase I study was to establish quantitative relations between process variables in radial forging of gun barrels. Thus, a basis would be established for optimizing the process conditions. The slab method of analysis has been used to ...

G. D. Lahoti R. Altan

1974-01-01

16

Cold forging of high strength aluminum alloys and the development of new thermomechanical processing  

Microsoft Academic Search

Cold forging is a process suitable for manufacturing low-cost and high quality automotive components in high strength aluminium alloys. This method is particularly suitable for parts with narrow geometrical tolerances, good concentricity, smooth surface finish and for near net shape products. However, an increasing request for producing components at a lower cost requires even more economical production processes. Forming in

Ola Jensrud; Ketill Pedersen

1998-01-01

17

Development of ion-implanted hard coatings for industrial applications in low lubricated cold forging processes  

Microsoft Academic Search

Cold forging is characterized by high abrasive and adhesive tool wear. Therefore chemical vapour deposited (CVD) and physical vapour deposited (PVD) coatings are used. In the future, for environmental and economical reasons, a progressive reduction in the use of lubricants will be required, or even dry manufacturing processes. As a consequence, the tool surface must substitute for the properties of

F. Seidel; H.-R. Stock; P. Mayr

1996-01-01

18

Processing and properties of hot-forged bulk superconductors  

SciTech Connect

(Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) and TlBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Tl-1223) bars were hot forged in air at 820--850C. Final stresses of 2--3 MPa were sufficient to produce >95% dense Bi-2223 bars. In contrast, stresses to {approx}42 MPa were able to produce only 75--80% dense Tl-1223 bars. The Bi-2223 bars were more phase-pure and exhibited much stronger c-axis textures than the Tl-1223. Maximum critical current densities at 77 K were 8 {times} 10{sup 4} A/cm{sup 2} for the Bi-2223 and 2 {times} 10{sup 4}/cm{sup 2} for the Tl-1223. Fracture strength and toughness values were 140 MPa and 2.9 MPa{radical}m for the Bi-2223 and 50 MPa and 0.5 MPa{radical}m for the Tl-1223.

Goretta, K.C.; Lanagan, M.T.; Picciolo, J.J.; Youngdahl, C.A.; Balachandran, U. [Argonne National Lab., IL (United States); Chen, Nan [Illinois Superconductor Corp., Mount Prospect, IL (United States)

1995-12-31

19

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

Microsoft Academic Search

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

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

1998-01-01

20

3D FEM simulation of the multi-stage forging process of a gas turbine compressor blade  

Microsoft Academic Search

Due to the complicated three-dimensional geometry and the non-steady state contact between the workpiece and the die surface, the simulation of blade forging process performed so far has been restricted to two-dimensional plane-strain problems or simplified three-dimensional deformational cases throughout which some simplifications and assumptions are employed. This study attempts to simulate an entire forging process of a gas turbine

Cheng Lv; Liwen Zhang; Zhengjun Mu; Qingan Tai; Quying Zheng

2008-01-01

21

The effects of casting and forging processes on joint properties in friction-welded AISI 1050 and AISI 304 steels  

Microsoft Academic Search

The aim of the present study was to investigate the effects of investment casting and forging process on the microstructure\\u000a and mechanical properties of friction weldments, AISI 1050–AISI 304. A continuous-drive friction welding device with the automatic\\u000a control ability of friction time and forging pressure was designed and constructed. Factorial design of experiments was performed\\u000a to join investment cast AISI

Tolga Y. Sunay; Mumin Sahin; Sabri Altintas

2009-01-01

22

Application of CAE in cold forging and heat treatment processes for manufacturing of precision helical gear part  

Microsoft Academic Search

In this study, numerical simulations, using the general-purpose process simulation software DEFORM-3D\\/HT, were carried out for the design of the cold forged precision helical gear used for the automotive steering part. The helical gear forging was carried out using the designed die set. From the simulation results, forming load, normal pressure, effective strain distributions on the workpiece, and stress distributions

Soo-Young Kim; Satoshi Kubota; Masahito Yamanaka

2008-01-01

23

Changes in magnetic parameters of neutron irradiated SA 508 Cl. 3 reactor pressure vessel forging and weld surveillance specimens  

NASA Astrophysics Data System (ADS)

Irradiation-induced changes in the magnetic parameters and mechanical properties were measured and compared to explore possible correlations for reactor pressure vessel (RPV) forging and weld surveillance Charpy specimens which were irradiated to the neutron fluence of 2.3×1019 n/cm2 (E>1.0 MeV) in a typical pressurized water reactor environment at 290 °C. For mechanical property parameters, Vickers microhardness, tensile and Charpy impact tests were performed and saturation magnetization (Ms), remanence (Mr), coercivity (Hc), and Barkhausen noise amplitude (BNA) were measured for magnetic parameters for both unirradiated and irradiated specimens, respectively. Results of mechanical property measurements showed an increase in yield and tensile strength, Vickers microhardness, 30 ft. lb indexed RTNDT and a decrease in Charpy upper-shelf energy irrespective of forging and weld metals. Hysteresis loops appeared to turn clockwise, resulting in an increase in Hc, and BNA appeared to decrease after irradiation. Both magnetic parameters showed viable correlations to the changes in mechanical parameters (Vickers microhardness, Charpy upper shelf energy) due to irradiation. Even limited, the present study seems to show additional possibilities for the application of this magnetic method in monitoring the mechanical parameter changes due to neutron irradiation.

Chi, Se-Hwan; Chang, Kee-Ok; Hong, Jun-Hwa; Kuk, Il-Hiun; Kim, Chong-Oh

1999-04-01

24

Study on Pot Forming of Induction Heater Type Rice Cookers by Forging Cast Process  

NASA Astrophysics Data System (ADS)

This paper describes a study result on pot fabrication by the forging cast process of stainless steel with aluminum. Rice cooked with the new bowl-shaped pot for the induction heater type rice cookers is better tasting than rice cooked with the conventional cylindrical one, due to the achievement of better heat conduction and convection. The conventional pot is made of the clad sheet, consisting of stainless steel and aluminum. However, it is rather difficult to form a bowl shape from the clad sheet, primarily due to the problem of a material spring back. The fabrication of a new type of a pot was made possible by means of the adoption of a forging cast process instead of the clad sheet. In this process, iron powder is inserted between stainless steel and aluminum in order to alleviate the large difference on the coefficient of expansion between each material. It was made clear that the application of two kinds of iron particle, namely 10 ?m size powder on the stainless steel side and 44 ?m on the aluminum side, enables the joints to become strong enough. The joint strength of the new pot by this fabrication process was confirmed by the tests of the shear strength and the fatigue tests together with the stress analysis.

Ohnishi, Masayuki; Yamaguchi, Mitsugi; Ohashi, Osamu

25

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

SciTech Connect

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

Kerry Barnett

2003-03-01

26

Liquid State Forging: Novel Potentiality to Produce High Performance Components, Process, Plant and Tooling  

NASA Astrophysics Data System (ADS)

The paper deals about a new patented process able to the production of high resistance and high toughness parts, taking into consideration also the tooling need. The molten alloy is introduced into the die cavity at low pressure, then the alloy is forged. The forging action takes place during the alloy solidification process, favouring the reduction of the duration of the process and the production of parts characterised by very high mechanical and ductility properties. The very high mechanical characteristics of the produced parts are obtained thank to their very low porosity content, as well as to their unique microstructure features. Moreover, the process allow the optimisation of the yield of the alloy, in fact the feeding system and the risers are practically absent, this means minimum production of scraps to be recycled. After a short description of the main features of the equipment and of the process, the work take into consideration the aluminium based produced parts, in their as cast state and after T6 heat treatment, comparing their characteristics with those obtainable by the most traditional low pressure and gravity casting processes. In particular, samples for the evaluation of the mechanical properties have been machined from the produced parts to obtain their tensile strength, together with their ductility characteristics. The maximum attained hardness values have also been evaluated. Tensile strength higher than 440 MPa, with elongation up to 18% with hardness higher than 125 HB are easily attainable on Al alloys type A356. Light microscopy observations performed on the transverse section of polished samples and the analysis of the fracture surfaces after mechanical tests allowed to focus the attention on the microstructure details and to highlight the ductile aspects of the fracture to confirm the high quality and high performance of the produced parts.

Rosso, M.; Zago, A.; Claus, P.; Motoiu, P.

2007-04-01

27

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.

28

Industrial Process Design for Manufacturing Inconel 718 Extremely Large Forged Rings  

NASA Astrophysics Data System (ADS)

Inconel 718 is a Ni-Fe-based superalloy that has been central to the gas turbine industry since its discovery in 1963. While much more difficult to process than carbon or stainless steels, among its superalloy peers Inconel 718 has relatively high forgeability and has been used to make discs, rings, shells, and structural components. A metal forming process design algorithm is presented to incorporate key criteria relevant to superalloy processing. This algorithm was applied to conceptual forging and heat treating extremely large rings of Inconel 718 of diameter 1956 mm (77in) and weight 3252 kg (7155 lb). A 3-stage standard thermomechanical (TMP) processing was used, where Stage 1 strain varied from 0.1190 to 0.2941, Stage 2 from 0.0208 to 0.0357 and Stage 3 from 0.0440 to 0.0940. This was followed by heat treatment of a solution anneal (954°C/1750°F for 4 hour hold), air cool, then a double aging (718°C/1325°F for 8 hour hold; furnace cool to 621°C/1150°F 56°C/100°F per hr; 18 hour total time for both steps). Preliminary mechanical testing was performed. Average yield strength of 951 MPa/138 ksi (longitudinal) and 979 MPa/142 ksi (axial) was achieved. Tensile strengths were 1276 MPa/185 ksi (longitudinal) and 1255 MPa/182 ksi (axial). Elongations and reduction of areas attained were, respectively, 18 (long) and 25 (axial) and 28 (long) and 27 (axial).

Ambielli, John F.

29

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

30

Process demonstration and cost analysis of a mass production forging technique for automotive turbine wheels: Phase II. Final report, January 1975--March 1977  

SciTech Connect

Low cost fabrication of integrally-bladed automotive turbine wheels utilizing the GATORIZING forging process was demonstrated. The capability of the forging process was characterized as to blade shape, and the effect of the blade shape on Chrysler baseline engine turbine efficiency was analytically defined. Actual baseline engine turbine wheels were fabricated from IN100 and AF2-1DA for evaluation. A mass production cost estimate was generated for manufacturing large production quantities.

Allen, M.M.; Larson, K.J.; Walker, B.H.

1977-07-01

31

Consolidation of nanostructured metal powders by rapid forging: Processing, modeling, and subsequent mechanical behavior  

Microsoft Academic Search

Fe-10Cu powders containing 20-nm grains were produced by attritor milling of elemental powders in argon. A rapid powder forging\\u000a technique was developed to consolidate the powders into fully dense compacts while maintaining nanoscale grain sizes. Grain\\u000a growth during the consolidation was controlled by reducing the time of exposure at elevated temperature to a few minutes or\\u000a less, a technique which

G. R. Shaik; W. W. Milligan

1997-01-01

32

Consolidation of nanostructured metal powders by rapid forging: Processing, modeling, and subsequent mechanical behavior  

Microsoft Academic Search

Fe?10Cu powders containing 20-nm grains were produced by attritor milling of elemental powders in argon. A rapid powder forging\\u000a technique was developed to consolidate the powders into fully dense compacts while maintaining nanoscale grain sizes. Grain\\u000a growth during the consolidation was controlled by reducing the time of exposure at elevated temperature to a few minutes or\\u000a less, a technique which

G. R. Shaik; W. W. Milligan

1997-01-01

33

Process Damping Parameters  

NASA Astrophysics Data System (ADS)

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

Turner, Sam

2011-12-01

34

Mechanical Properties and Microstructure of Thin Plates of A6061 Wrought Aluminum Alloy Using Rheology Forging Process with Electromagnetic Stirring  

NASA Astrophysics Data System (ADS)

We propose the possibility of fabricating A6061 thin plates using the rheology forging process. Electromagnetic stirring (EMS) is used to fabricate a semi-solid slurry. A thin plate is formed by injecting the slurry into the forging die. When the punch speed used to compress the slurry is low, turbulent flow occurs. When the punch speed is high, laminar flow occurs, and the solid and liquid phases move simultaneously. For a pressure of 150 MPa or below, incomplete filling behavior and cracks occur. For a pressure of 200 MPa or above, a durable formed product can be obtained. However, the differences between the mechanical properties according to the application of EMS and pressure are slight. The microstructure of the slurry without EMS has an unclear distinction between the liquid phase and solid phase. However, the microstructure of the thin plates formed by using this slurry has a clear distinction between the liquid and solid with respect to the spheroid shapes. The tensile strength and elongation for a thin plate formed with a punch speed of 300 mm/s and pressure of 250 MPa with EMS slurry are 169 MPa and 11.0 pct, respectively. After T6 heat treatment, the tensile strength improves to 305 MPa.

Jin, Chul Kyu; Bolouri, Amir; Kang, Chung Gil

2013-12-01

35

Mechanical Properties and Microstructure of Thin Plates of A6061 Wrought Aluminum Alloy Using Rheology Forging Process with Electromagnetic Stirring  

NASA Astrophysics Data System (ADS)

We propose the possibility of fabricating A6061 thin plates using the rheology forging process. Electromagnetic stirring (EMS) is used to fabricate a semi-solid slurry. A thin plate is formed by injecting the slurry into the forging die. When the punch speed used to compress the slurry is low, turbulent flow occurs. When the punch speed is high, laminar flow occurs, and the solid and liquid phases move simultaneously. For a pressure of 150 MPa or below, incomplete filling behavior and cracks occur. For a pressure of 200 MPa or above, a durable formed product can be obtained. However, the differences between the mechanical properties according to the application of EMS and pressure are slight. The microstructure of the slurry without EMS has an unclear distinction between the liquid phase and solid phase. However, the microstructure of the thin plates formed by using this slurry has a clear distinction between the liquid and solid with respect to the spheroid shapes. The tensile strength and elongation for a thin plate formed with a punch speed of 300 mm/s and pressure of 250 MPa with EMS slurry are 169 MPa and 11.0 pct, respectively. After T6 heat treatment, the tensile strength improves to 305 MPa.

Jin, Chul Kyu; Bolouri, Amir; Kang, Chung Gil

2014-06-01

36

A Study of the Mechanics of Closed-die Forging. Important Factors in Selection and Use of Equipment for Forging.  

National Technical Information Service (NTIS)

The increasing degree of sophistication observed in the forging industry requires a sound and fundamental understanding of equipment capabilities and characteristics. The equipment behavior influences the forging process since it determines the feasibilit...

T. Altan H. J. Henning A. M. Sabroff

1969-01-01

37

Necklace structure obtained by forging Astroloy supersolidus-sintered preforms  

Microsoft Academic Search

A new and original densification process of nickel-based superalloys consists in forging supersolidus-sintered preforms. From the coarse-grained structure of the material sintered in the presence of a liquid phase, forging at a high deformation ratio can lead to a duplex structure (usually called “necklace” structure) as can be obtained by conventional HIP + forge or cast\\/wrought routes. Optimal forging conditions

M. Jeandin

1982-01-01

38

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.

39

Simulation of 7050 Wrought Aluminum Alloy Wheel Die Forging and its Defects Analysis based on DEFORM  

NASA Astrophysics Data System (ADS)

Defects such as folding, intercrystalline cracking and flow lines outcrop are very likely to occur in the forging of aluminum alloy. Moreover, it is difficult to achieve the optimal set of process parameters just by trial and error within an industrial environment. In producing 7050 wrought aluminum alloy wheel, a rigid-plastic finite element method (FEM) analysis has been performed to optimize die forging process. Processing parameters were analyzed, focusing on the effects of punch speed, friction factor and temperature. Meanwhile, mechanism as well as the evolution with respect to the defects of the wrought wheel was studied in details. From an analysis of the results, isothermal die forging was proposed for producing 7050 aluminum alloy wheel with good mechanical properties. Finally, verification experiment was carried out on hydropress.

Shi-Quan, Huang; You-Ping, Yi; Yu-Xun, Zhang

2010-06-01

40

Phased Array Ultrasonic Inspection of Titanium Forgings  

NASA Astrophysics Data System (ADS)

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

Howard, P.; Klaassen, R.; Kurkcu, N.; Barshinger, J.; Chalek, C.; Nieters, E.; Sun, Zongqi; Defromont, F.

2007-03-01

41

Phased Array Ultrasonic Inspection of Titanium Forgings  

SciTech Connect

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

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

2007-03-21

42

Influence of the nitriding time in the wear behaviour of an AISI H13 steel during a crankshaft forging process  

Microsoft Academic Search

The influence of nitriding time in the wear behaviour of an AISI H13 hot work steel used on forging dies has been studied. AISI H13 steel was nitrided by a patented sursulf bath, varying nitriding time from 1 to 24h. Optical microscopy and microhardness deep profile through the nitrided layer were performed for each nitriding time. Standard pin-on-disk wear test

G. Castro; A. Fernández-Vicente; J. Cid

2007-01-01

43

Estimation of friction under forging conditions by means of the ring-on-disc test  

SciTech Connect

In order to understand the tribological processes and interactions in the tool-workpiece-interface systematically, basic experiments that allow an independent variation of influencing parameters are necessary. The ring-on-disc test is a popular model experiment that is often used in tribological analyses at low normal contact pressures.The scope of the paper is an analysis of the applicability of the ring-on-disc test for high normal pressures as used in forging processes, using aluminium AA6082 as workpiece material. It turned out, that this test is a convenient method to measure friction under forging conditions.

Buchner, Bernhard; Umgeher, Andreas; Buchmayr, Bruno [University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria)

2007-04-07

44

Isothermal Forging and Its Effect on the Microstructure of Powder Route Nickel Alloy AP1.  

National Technical Information Service (NTIS)

The influence of initial billet hot isostatic pressing treatment and forging parameters on the microstructure of isothermally formed powder AP1 were investigated. Strain, strain rate, and forging temperature were varied using a microprocessor controlled s...

C. Wilkinson

1986-01-01

45

Mechanical Testing Development for Reservoir Forgings  

SciTech Connect

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

Wenski, E.G.

2000-05-22

46

Principles of Incremental Forging.  

National Technical Information Service (NTIS)

Plasticine, lead and commercial purity aluminum were demonstrated to be suitable room temperature analog materials for the simulation of hot forging materials such as alloy steels and titanium alloys in axially symmetric upsetting experiments with materia...

P. H. Abramowitz J. A. Schey

1970-01-01

47

NEW FORGE WELDING OF ALUMINUM AND MAGNESIUM ALLOYS  

Microsoft Academic Search

A new forge-welding process for weldng high-strength aluminum and ; magnesium alloys has been developed. This forge welding consists of heating the ; parts to be welded to a temperature which is high enough to allow good uniform ; flow of the materials without cracking and yet the temperature is sufficiently ; low that the samples are not overaged or

L. A. Cook; D. G. Shafer

1958-01-01

48

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

49

Friction and wear in hot forging of steels  

SciTech Connect

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

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

2007-04-07

50

Hot Cutting of Real-Time Cast-Forged GS Ductile Iron for Automotive Rods  

NASA Astrophysics Data System (ADS)

In the global economy context, automotive industry suppliers have to keep a constant advance on products design and manufacturing process. Concerning automotive rods, the substitution of forged steel by spherical graphite iron (SG iron) with high mechanical properties constitutes a valid economic alternative. Such rods are produced using a complex coupled process: casting and forging followed by an austempered heat treatment. The forging operation is capable to shape the cast rod which introduces hot deformation to increase mechanical properties of net-shape SG iron rod. However, the intermediate re-heating between casting and forging must be avoided to keep competitive manufacturing costs. A major concern of this new process development is the cracks produced in rod's surface which are consecutive to hot spruing involved after casting operations. This issue is addressed in this paper which discusses the physical mechanisms involved in the hot ductile damage of SG iron. Hot cutting tests were performed to simulate the spruing operation which shows the close interactions between microstructure, machining parameters and resulting damages. The damage mechanisms in terms of crack initiation and its growth have been studied with respect to the constituent phases (austenite+graphite nodules), the cut surface morphology and the hot cutting performance.

Fouilland, Laurence; Mansori, Mohamed El

2011-01-01

51

Welded preforms for forging  

Microsoft Academic Search

While tailor-welded preforms are commonly used in sheet forming, to date, similar technology has not been developed for bulk forming. In the present paper, the results of a study that was conducted to investigate the feasibility of solid-state welded preforms in forging is presented. Both same-metal and bi-metal combinations were considered and results indicate that in general friction welded preforms

Joseph Domblesky; Frank Kraft; Benjamin Druecke; Bart Sims

2006-01-01

52

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

NASA Astrophysics Data System (ADS)

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

Babu, Sailesh

53

Roughness parameter selection for novel manufacturing processes.  

PubMed

This work proposes a method of roughness parameter (RP) selection for novel manufacturing processes or processes where little knowledge exists about which RPs are important. The method selects a single parameter to represent a group of highly correlated parameters. Single point incremental forming (SPIF) is used as the case study for the manufacturing process. This methodology was successful in reducing the number of RPs investigated from 18 to 8 in the case study. PMID:23460493

Ham, M; Powers, B M

2014-01-01

54

Influence Of Forming Machine Stiffness On Product Quality In Hot Forging Operations  

NASA Astrophysics Data System (ADS)

The quality of forged components is strictly dependent on the micro-structural phenomena occurring during the manufacturing chain that may cause significant changes in the physical and mechanical features of the final product. Some of these changes take place during the deformation phase and depend on the forming machine characteristics in term of machine kinematics, total elastic deflections of the press system and contact-time. The press stiffness influences the velocity-versus-time curve under load, varying the contact pressure and the heat transfer between the tools and the workpiece and, consequently, the global process conditions. This paper deals with the evaluation of the influence that the forging machine exerts on the process parameters and the quality of the final component in terms of its microstructure distribution after forging. The approach is based on a simulative environment that combines experimental measurements, FE simulation and inverse analysis techniques. A case study, in which operating conditions approximate hot forging of a turbine aerofoil section, is presented. Results of experiments show the influence of machine characteristics on the quality of final product.

Croin, M.; Ghiotti, A.; Bruschi, S.

2007-04-01

55

PARAMETER DESIGN FOR SHEET METAL HYDROFORMING PROCESSES  

Microsoft Academic Search

Summary This paper presents results of a cooperative research programme on the development of new offline process design methods for sheet metal hydroforming processes. Fundamental investigations regarding the influence of process parameters and their interplay are discussed. Parameters are to be chosen such that the high-pressure sheet metal forming process is optimised with respect to multiple quality characteristics (multi-response) i.e.

U. Gather; W. Homberg; M. Kleiner; Ch. Klimmek; S. Kuhnt

56

Isothermal Roll Forging of T55 Compressor Blades.  

National Technical Information Service (NTIS)

The objective of this manufacturing technology program was to demonstrate feasibility to produce T55 compressor blades by isothermal roll forging within 0.010 inch of drawing tolerances. This objective was accomplished through process definition and appli...

F. K. Rose A. G. Metcalfe

1977-01-01

57

Forging of Powder Metallurgy Gears.  

National Technical Information Service (NTIS)

The objective of this program was to produce a very near-net shape spur gear by isothermal forging of a powder metallurgy 4600 grade preform. Die fill and densification on test coupons were complete at a forging temperature of 1650F (900C), pressure of 10...

B. L. Ferguson D. T. Ostberg

1980-01-01

58

Establishment of a Computer-Aided Design (CAD)/Computer-Aided Manufacturing (CAM) Process for the Production of Cold Forged Gears.  

National Technical Information Service (NTIS)

In Phase I of the program, computer-aided design techniques have been developed to design the dies for cold forging spur and helical gears. The geometry of the spur and the helical has been obtained from the kinematics of the hobbing/shaper machines and c...

D. J. Kuhlmann P. S. Raghupathi T. Altan

1984-01-01

59

A numerical simulation of super-plastic die forging process for Zr-based bulk metallic glass spur gear  

Microsoft Academic Search

Because of the high strength and hardness at room temperature, the processing of bulk metallic glasses (BMGs) is very difficult whether by machining or by plastic forming, and the applications of BMGs are restricted. The development of super-plastic precise forming technology, utilizing viscous flowing property of BMGs exhibited in super-cooled liquid region, will lead to wider applications of the alloys.

Zhihao Zhang; Jianxin Xie

2006-01-01

60

Automatic feature extraction from micrographs of forged superalloys  

NASA Astrophysics Data System (ADS)

The manual determination of metallurgical parameters of forged superalloys can be dramatically improved by automatic, image-processing-based feature extraction. With the proposed methods, the typical errors during grain size estimation for Inconel 718 and Allvac 718Plus ™ , caused by twins and other artifacts like scratches, can be eliminated. Different processing strategies for grain size estimation allow the application of a wide range of ASTM grain size numbers from G3 to G12 with the typical variations in the manifestation of metallurgical details and the magnification-related limitations of image quality. Intercept counting strategies show advantages for samples with pronounced anisotropy and can produce detailed statistics on grain orientation. In addition to a single grain size number, grain size histograms offer a more precise description of the material properties.

Berhuber, E.; Rinnhofer, A.; Stockinger, M.; Benesova, W.; Jakob, G.

2008-07-01

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

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

1996-01-01

63

Nontactile registration of process parameters in a continuous rolling process  

NASA Astrophysics Data System (ADS)

Industrial automation, robotics and automatic inspections include the processing of image sequences. The data rate can be very high in dynamic image systems and often real-time processing requires the use of special hardware. As an example for a typical image processing problem the following paper presents a visual motion detection systems which allows non- tactile registration of process parameters in a continuous rolling process. During an image sequence analysis the motion and the dimension of hot tubes will be measured on-line by a real-time image processing system. The motion is detected and measured by observing the translation of specific templates on the surface within a sequence of grey-scale images. This motion is analyzed by using a correlation procedure. The introduction of a state space model for the process parameters which includes a-priori knowledge and dynamic knowledge of the rolling process allows a compact motion description.

Weller, Uwe

1993-08-01

64

Process parameters calibration in 3D tube hydroforming processes  

NASA Astrophysics Data System (ADS)

In tube hydroforming the concurrent actions of pressurized fluid and mechanical feeding allow to obtain tube shapes characterized by complex geometries such as different diameters sections and/or bulged zones. What is crucial in such processes is the proper design of operative parameters aimed to avoid defects (for instance shape defects or ductile fractures). The main process parameters are material feeding history (i.e. the punches velocity history) and internal pressure path during the process. In more complex three dimensional processes, also the action of a counterpunch is generally useful to reduce thinning in particular in expansion zones of the tube (i.e. T or Y shaped tubes). The good calibration of these parameters allows the optimal design of the process; in fact many researches have proposed different approaches to the optimization of these parameters. Generally, the main goals in the optimization approaches concern the control of thinning and the reaching of the desired final shape. In this paper, a fully three dimensional tube hydroforming operation is studied, aimed to produce a T-shaped tube. A numerical simulations campaign was developed in order to analyze the influence of process parameters on the final product quality; in particular, the influence of the pressure path was considered in order to evaluate the effects of wrinkling phenomenon on thickness distribution. The basic idea is that the possibility to determine useful wrinkles at an early stage of the process may lead to better results in terms of maximum thinning on the final part. The numerical investigations led to a knowledge base about the process mechanics and the influence of wrinkling behavior which is very effective in order to implement an optimization procedure on the process parameters.

di Lorenzo, R.; Ingarao, G.; Micari, F.

2007-04-01

65

Effect of Deformation Rate on JBK-75 Stainless Steel Forgings.  

National Technical Information Service (NTIS)

A parametric study was conducted to evaluate the effect of forging rate and forging temperature on the strength and microstructure of a precipitation-hardened, austenitic stainless steel forging. High and low forging rates were achieved using a high energ...

B. C. Odegard

1987-01-01

66

Fitting function representation for strain fields and its application to the optimizing process  

NASA Astrophysics Data System (ADS)

A fitted function method to describe the strain fields during forging was discussed to optimize the homogeneous distribution of strain in the axial forging zones during successive stretching. The results are verified by experiment and numerical simulation, and the deviations between experiment and simulation are less than 24%. Therefore, the fitted function method can be applied to optimize the stretching process for large forgings. The optimal value of feed determined by the analytic method ensures that the degree of inhomogeneity in strain in the axial ingot zone is less than 6%. This work provides a mathematic model to optimize technological parameters in stretch forging of large ingots.

Chen, Kun; Liu, Ke-jia; Wei, Li-qun; Yang, Yi-tao

2014-06-01

67

Prediction of Microstructure in High-Strength Ductile Forging Parts  

NASA Astrophysics Data System (ADS)

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

Urban, M.; Keul, C.; Back, A.; Bleck, W.; Hirt, G.

2010-06-01

68

Parameter identification in multinomial processing tree models.  

PubMed

Multinomial processing tree models form a popular class of statistical models for categorical data that have applications in various areas of psychological research. As in all statistical models, establishing which parameters are identified is necessary for model inference and selection on the basis of the likelihood function, and for the interpretation of the results. The required calculations to establish global identification can become intractable in complex models. We show how to establish local identification in multinomial processing tree models, based on formal methods independently proposed by Catchpole and Morgan (1997) and by Bekker, Merckens, and Wansbeek (1994). This approach is illustrated with multinomial processing tree models for the source-monitoring paradigm in memory research. PMID:20805606

Schmittmann, Verena D; Dolan, Conor V; Raijmakers, Maartje E J; Batchelder, William H

2010-08-01

69

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

70

Simulation of microstructures for Alloy 718 blade forging using 3D FEM simulator  

Microsoft Academic Search

Mechanical properties of Ni–Cr–Fe-based Alloy 718 depend very much on the grain size, as well as the presence of strengthening phases, ?? and ??. The grain size of superalloy parts can be controlled by the thermo-mechanical processes, including heating, forging and cooling sequences. In order to predict the evolution of grain size in Alloy 718 blade forging, a series of

Young-Sang Na; Jong-Taek Yeom; Nho-Kwang Park; Jai-Young Lee

2003-01-01

71

Forging preform design with shape complexity control in simulating backward deformation  

Microsoft Academic Search

This paper presents a preform design method which employs an alternative boundary node release criterion in the finite element simulation of backward deformation of forging processes. The method makes use of the shape complexity factor which provides an effective measure of forging difficulty. The objective is to release die contacting nodes in a sequence which will minimize the geometric complexity

Guoqun Zhao; Ed Wright; Ramana V. Grandhi

1995-01-01

72

Comparison of Aluminum Alloy 7050, 7049, MA52, and 7175-T736 Die Forgings.  

National Technical Information Service (NTIS)

Die forgings in aluminum alloys 7050, 7049, and MA52 were fabricated and evaluated for resistance to stress-corrosion cracking, quench sensitivity, and fracture toughness. In addition, all Alcoa data on 7050, 7049, and special process 7175-T7X die forging...

J. T. Staley

1973-01-01

73

New Trends in Forging Technologies  

Microsoft Academic Search

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

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

2011-01-01

74

Social Studies: Forging a Nation.  

ERIC Educational Resources Information Center

Forging a Nation, a curriculum guide for teachers of grades 7 through 9 as they plan instructional programs in American Studies, is part of a total effort to revise curriculum to fit the quinmester administrative organization of schools. Primary emphasis is upon using the topic of the American Revolution as a basis for studying conflict and…

Hanson, Paul S.

75

A novel method for predicting the grain size of superalloy forgings based on the fuzzy method and the FEM  

Microsoft Academic Search

Grain size is one of the important indexes for characterizing the microstructures and properties of superalloy forgings. Under the condition that the quality of the raw material is specified, the grain size of superalloy forgings is the result of synthetic inter action of thermomechanical parameters. Thus, the relationship between grain size and thermomechanical parameters belongs to the fuzzy concept for

Z. J. Luo; Q. Yang; D. Liu

2000-01-01

76

Development of high purity large forgings for nuclear power plants  

NASA Astrophysics Data System (ADS)

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

Tanaka, Yasuhiko; Sato, Ikuo

2011-10-01

77

Nonstationary magnetotelluric data processing with instantaneous parameter  

NASA Astrophysics Data System (ADS)

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

Neukirch, M.; Garcia, X.

2014-03-01

78

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

79

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

80

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

81

Design for Manufacturability: Design for Forging, Part II.  

National Technical Information Service (NTIS)

Practical design recommendations for conventional forgings are presented as part of a research project entitled 'Design for Forging Handbook.' The material is based on information from forging users, producers, and technical associations. Recommendations ...

A. Rigioni C. Poli G. Boothroyd

1981-01-01

82

Parameter space exploration with Gaussian process trees  

Microsoft Academic Search

Computer experiments often require dense sweeps over input parameters to obtain a qualitative understanding of their response. Such sweeps can be prohibitively expensive, and are unnecessary in regions where the response is easy predicted; well-chosen designs could allow a mapping of the response with far fewer simulation runs. Thus, there is a need for computationally inexpensive surrogate models and an

Robert B. Gramacy; Herbert K. H. Lee; William G. Macready

2004-01-01

83

Residual stress in 7449 aluminium alloy forgings  

Microsoft Academic Search

The through thickness residual stress distributions within three 120mm thick rectilinear forgings, made from the high strength aluminium alloy 7449 have been measured using both neutron diffraction and deep hole drilling. Neutron diffraction measurements were made on two instruments, one using a pulsed spallation neutron source, the other a steady state reactor source. Heat treatment of the forgings included a

J. S. Robinson; S. Hossain; C. E. Truman; A. M. Paradowska; D. J. Hughes; R. C. Wimpory; M. E. Fox

2010-01-01

84

Reactor pressure vessel with forged nozzles  

DOEpatents

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

Desai, Dilip R. (Fremont, CA)

1993-01-01

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

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

87

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

88

Approach to a Markovian Realization of Two-Parameter Processes.  

National Technical Information Service (NTIS)

The Markovian realization problem for a two-parameter process, when the pasts are defined by an increasing sequence of left half-planes, is considered. Explicit results for processes with rational spectral densities are given.

H. Korezlioglu P. Loubaton

1986-01-01

89

Parameter Optimization of Ultrasonic Machining Process Using Nontraditional Optimization Algorithms  

Microsoft Academic Search

The optimum selection of process parameters is essential for advanced machining processes, as these processes incur high initial investment, tooling cost, and operating and maintenance costs. This article presents optimization aspects of an important advanced machining process known as ultrasonic machining (USM). The objective considered is maximization of material removal rate (MRR) subjected to the constraint of surface roughness. The

Ravipudi Venkata Rao; P. J. Pawar; J. P. Davim

2010-01-01

90

29 CFR 1910.218 - Forging machines.  

Code of Federal Regulations, 2010 CFR

...fly off or fall in event of failure. (3) Hammers and presses. (i) All hammers shall be positioned or installed in such a manner...factor Maximum recommended weight of forging hammer for timber used Maximum allowable length...

2009-07-01

91

29 CFR 1910.218 - Forging machines.  

Code of Federal Regulations, 2010 CFR

...fly off or fall in event of failure. (3) Hammers and presses. (i) All hammers shall be positioned or installed in such a manner...factor Maximum recommended weight of forging hammer for timber used Maximum allowable length...

2010-07-01

92

Selecting forged aluminum for automotive applications  

SciTech Connect

With the current and future efforts to downsize automobiles and reduce their weight, strong lightweight materials, in various product forms, are being substituted for many traditionally ferrous components. One of the substitute materials is aluminum, which although itself is not new to automobiles is finding novel applications as forgings in critical chassis and suspension areas. The 1984 Corvette provides an excellent example of how the use of forged aluminum can reduce unsprung and overall weight as well as improve performance without compromising the integrity of the vehicle. Using aluminum as forgings permits taking maximum advantage of its high strength-to-weight ratio, excellent ductility and toughness, and good corrosion resistance. This paper discusses the various considerations to be entertained when looking at aluminum forgings for automotive applications and the benefits of planning for these lightweight parts early in the design phase.

Holtz, M.A.; Davis, J.; Crawford, D.

1984-01-01

93

Laser 3D Machining with Variable Process Parameters  

NASA Astrophysics Data System (ADS)

An experimental study is presented to investigate the effects of laser cutting conditions on kerf geometry with variable process parameters. Laser traverse speed, laser power and laser focal position related to the specimen quality are varied during the cutting process to simulate the situations encountered in practice. Various trends of the kerf geometrical features in terms of the varying process parameters are presented and analyzed, and shown to be reasonable. Discussions are also given on kerf geometry control in situations where variable cutting parameters are used.

Wang, Xuyue; Wang, J.

2011-01-01

94

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

95

Design for manufacturability: Design for forging, part 2  

NASA Astrophysics Data System (ADS)

Practical design recommendations for conventional forgings are presented. Recommendations are considered for the design of individual features such as ribs, depressions, and holes. Forging tolerances and allowances, as well as forging drafting practices, are explained. Included are some guidelines for evaluating parting line location. Forging design data sheets are described. including a brief explanation of how they were obtained. The use of the handbook is illustrated by means of a practical example, outlining all of the necessary steps in the design of a forged product. The appendix contains a list of forging terms and their definitions.

Rigioni, A.; Boothroyd, G.

1981-04-01

96

The two-parameter Poisson–Dirichlet point process  

Microsoft Academic Search

The two-parameter Poisson–Dirichlet distribution is a probability distribution on the totality of positive decreasing sequences with sum 1 and hence considered to govern masses of a random discrete distribution. A characterization of the associated point process (that is, the random point process obtained by regarding the masses as points in the positive real line) is given in terms of the

Kenji Handa

2009-01-01

97

Efficient Parameter Estimation for Self-Similar Processes  

Microsoft Academic Search

Asymptotic normality of the maximum likelihood estimator for the parameters of a long range dependent Gaussian process is proved. Furthermore, the limit of the Fisher information matrix is derived for such processes which implies efficiency of the estimator and of an approximate maximum likelihood estimator studied by Fox and Taqqu. The results are derived by using asymptotic properties of Toeplitz

Rainer Dahlhaus

1989-01-01

98

High Integrity Forgings of Aluminum and Titanium Alloys.  

National Technical Information Service (NTIS)

The primary objective of this program was to establish the mechanical property and economic advantage of precision aluminum alloy and titanium alloy aerospace structural forging. The mechanical and fracture properties of the aluminum precision forging wer...

M. V. Hyatt D. H. Pasley I. Goodlet C. P. Yohn

1977-01-01

99

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

100

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

101

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

Microsoft Academic Search

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

Michael B. Prime; Mark A. Newborn; John A. Balog

2003-01-01

102

Spray forming of Ti 48.9Al (at.%) and subsequent hot isostatic pressing and forging  

Microsoft Academic Search

Binary Ti 48.9Al (at.%) has been processed via two different processing routes, both comprising the spray forming technology: (i) spray forming followed by hot isostatic pressing (HIP) and subsequent thermal treatments and (ii) spray forming and subsequent high temperature forging. After each process step, the material is characterized by porosity measurements, microstructural investigations and tensile tests. The as sprayed state

Rainer Gerling; F. P. Schimansky; G. Wegmann; J. X. Zhang

2002-01-01

103

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

PubMed

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

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

2012-05-01

104

Screw thread parameter measurement system based on image processing method  

NASA Astrophysics Data System (ADS)

In the industrial production, as an important transmission part, the screw thread is applied extensively in many automation equipments. The traditional measurement methods of screw thread parameter, including integrated test methods of multiparameters and the single parameter measurement method, belong to contact measurement method. In practical the contact measurement exists some disadvantages, such as relatively high time cost, introducing easily human error and causing thread damage. In this paper, as a new kind of real-time and non-contact measurement method, a screw thread parameter measurement system based on image processing method is developed to accurately measure the outside diameter, inside diameter, pitch diameter, pitch, thread height and other parameters of screw thread. In the system the industrial camera is employed to acquire the image of screw thread, some image processing methods are used to obtain the image profile of screw thread and a mathematics model is established to compute the parameters. The C++Builder 6.0 is employed as the software development platform to realize the image process and computation of screw thread parameters. For verifying the feasibility of the measurement system, some experiments were carried out and the measurement errors were analyzed. The experiment results show the image measurement system satisfies the measurement requirements and suitable for real-time detection of screw thread parameters mentioned above. Comparing with the traditional methods the system based on image processing method has some advantages, such as, non-contact, easy operation, high measuring accuracy, no work piece damage, fast error analysis and so on. In the industrial production, this measurement system can provide an important reference value for development of similar parameter measurement system.

Rao, Zhimin; Huang, Kanggao; Mao, Jiandong; Zhang, Yaya; Zhang, Fan

2013-08-01

105

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

106

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

107

NEW TOOL STEEL FOR WARM AND HOT FORGING  

Microsoft Academic Search

Currently there are few tool steels which are particularly s uitable for warm forging. A number of hot work tool steels, high speed steels and even cold work tool steels are used. Compared to hot forging (>1050 ?C) the loads required may be doubled. Compared to cold forging, the workpiece temper- ature is high (600 ?C-900 ?C), and therefore thermal

K. Fisher; H. Schweiger; J. Hasenberger; H. Dremel

108

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

109

Data processing and parameter extraction for cutting tool inspection  

NASA Astrophysics Data System (ADS)

The increase in awareness of the need to improve quality control on part machining efficiency has led to a great deal of research aimed at cutting tool geometry analysis. This paper presents a framework of preprocessing point-based data and extracting parameters after feature detection and data segmentation for cutting tool inspection, assuming unorganized measurement data. The data processing method, including data decimating, smoothing, normal and curvature estimating, denoising, sorting, as well as re-sampling, are exploited to meet the demands for high quality, data simplification for geometric analysis. We will discuss the geometry analysis for parameter extraction, including key feature point detection and key area segmentation based on general reverse engineering solutions and specific cutting tool characteristics. Based on the presented simplification methods using virtual slicing and rotary axial projection data, some cutting tool dimensional parameters can be extracted directly. Alternately, based on 2D points on a given cross section, a plurality of curves can be generated, and optimized by minimizing deviations between the set of points and the plurality of curves. Section parameters can then be extracted from the optimized curves. Furthermore, the methods and processes of multi-section based spatial parameter extraction will be illustrated. This paper presents experimental results and field tests. The experimental results show that the preprocessing is very robust and the parameter extraction results agree with what is expected.

Chen, T.; Du, X. M.; Zheng, J. M.; Harding, K. G.

2009-08-01

110

Analysis of GNSS receiver signal processing modification of scintillation parameters  

NASA Astrophysics Data System (ADS)

GNSS receivers have gained tremendous popularity in ionosphere and space weather monitoring. The output of GNSS receivers and resulting ionosphere scintillation indicators, however, are only convoluted scintillation signals and the receiver system function. This presentation will discuss different receiver signal processing algorithms impact on scintillation signal parameters. Scintillation signals from simulations and real data collected at high latitude and equatorial will be used to illustrate the receiver processing effects.

Morton, Y.

2013-12-01

111

Forging Collaborative Partnerships: The Waterloo Neighborhood Project.  

ERIC Educational Resources Information Center

The Forging Collaborative Partnerships Project in Waterloo, Iowa is a collaborative venture to assist voluntary agencies in developing tools and strategies to strengthen collaborative relationships among public and nonprofit child welfare agencies and other key stakeholders as they adopt a family-focused philosophy. This monograph details how the…

Gruenewald, Anne

112

Optimization of process parameters of mechanical type advanced machining processes using genetic algorithms  

Microsoft Academic Search

Generally, unconventional or advanced machining processes (AMPs) are used only when no other traditional machining process can meet the necessary requirements efficiently and economically because use of most of AMPs incurs relatively higher initial investment, maintenance, operating, and tooling costs. Therefore, optimum choice of the process parameters is essential for the economic, efficient, and effective utilization of these processes. Process

Neelesh K. Jain; V. K. Jain; Kalyanmoy Deb

2007-01-01

113

Determination of Optimal Parameters for SKD11 CNC Turning Process  

Microsoft Academic Search

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

Chorng-Jyh Tzeng; Yung-Kuang Yang

2008-01-01

114

Effect of Forging Strain Rate and Deformation Temperature on the Mechanical Properties of Warm-Worked 304L Stainless Steel  

SciTech Connect

Stainless steel 304L forgings were produced with four different types of production forging equipment – hydraulic press, mechanical press, screw press, and high-energy rate forging (HERF). Each machine imparted a different nominal strain rate during the deformation. The final forgings were done at the warm working (low hot working) temperatures of 816 ?C, 843 ?C, and 871 ?C. The objectives of the study were to characterize and understand the effect of industrial strain rates (i.e. processing equipment), and deformation temperature on the mechanical properties for the final component. Some of the components were produced with an anneal prior to the final forging while others were deformed without the anneal. The results indicate that lower strain rates produced lower strength and higher ductility components, but the lower strain rate processes were more sensitive to deformation temperature variation and resulted in more within-part property variation. The highest strain rate process, HERF, resulted in slightly lower yield strength due to internal heating. Lower processing temperatures increased strength, decreased ductility but decreased within-part property variation. The anneal prior to the final forging produced a decrease in strength, a small increase in ductility, and a small decrease of within-part property variation.

Nathan T Switzner

2010-02-01

115

Influence of material and process parameters on bursting during hydroforming process  

Microsoft Academic Search

Bursting is predicted using a 3D-necking criterion based on local instability analysis. First, forming limit diagram (FLD) are built to validate the approach and the influence of material parameters is illustrated. Secondly, the criterion is implemented in a finite element code devoted to the simulation of hydroforming processes. Bursting predictions are presented and the influence of process parameters is studied.

A. Lejeune; N. Boudeau; J. C. Gelin

2003-01-01

116

Upstream processes in antibody production: evaluation of critical parameters.  

PubMed

The demand for monoclonal antibody for therapeutic and diagnostic applications is rising constantly which puts up a need to bring down the cost of its production. In this context it becomes a prerequisite to improve the efficiency of the existing processes used for monoclonal antibody production. This review describes various upstream processes used for monoclonal antibody production and evaluates critical parameters and efforts which are being made to enhance the efficiency of the process. The upstream technology has tremendously been upgraded from host cells used for manufacturing to bioreactors type and capacity. The host cells used range from microbial, mammalian to plant cells with mammalian cells dominating the scenario. Disposable bioreactors are being promoted for small scale production due to easy adaptation to process validation and flexibility, though they are limited by the scale of production. In this respect Wave bioreactors for suspension culture have been introduced recently. A novel bioreactor for immobilized cells is described which permits an economical and easy alternative to hollow fiber bioreactor at lab scale production. Modification of the cellular machinery to alter their metabolic characteristics has further added to robustness of cells and perks up cell specific productivity. The process parameters including feeding strategies and environmental parameters are being improved and efforts to validate them to get reproducible results are becoming a trend. Online monitoring of the process and product characterization is increasingly gaining importance. In total the advancement of upstream processes have led to the increase in volumetric productivity by 100-fold over last decade and make the monoclonal antibody production more economical and realistic option for therapeutic applications. PMID:17920803

Jain, Era; Kumar, Ashok

2008-01-01

117

Sensors and the Influence of Process Parameters and Thin Films  

NASA Astrophysics Data System (ADS)

Design of semiconductor silicon sensors is based on physical principles and the variation of geometry and material parameters. Normally in MEMS design a conversion method from non electrical input to an electrical output signal is chosen to get a good linear sensor. During miniaturization and increase of the accuracy the device behaves no more linear. For different function (e.c. sensitivity, resolution) and quality parameters (e.c. drift, burst pressure) of a device temperature coefficients (TC) nonlinearities, hysteresis and so on take place. Additional during characterization you find offsets and other effects, not described in your physical model of the device. The reason for this is that in thin films values, like the k-factor of metallic resistance, are influenced of process parameters, inhomogeneities in the capacity are influenced by process steps or geometry parameters have influence to void generation. For sensor design this all has to be modeled, that means we have to investigate microscopic effects. The influence of thin layers to function of a sensor is shown for Yaw rate sensors, pressure sensors, mass flow sensors and chemical sensors.

Krauss, Hans-Reiner

118

Fermentation parameters influencing higher alcohol production in the tequila process  

Microsoft Academic Search

In the fermentation process of tequila, the type of yeast strain, the temperature (30 or 35°C) and the C\\/N ratio (62 or 188) had a significant influence in the level of higher alcohols produced. On the contrary, other parameters like nitrogen source [urea or (NH)SO] and inoculum amount (5% or 10%), have little or no influence on the production of

Leticia Pinal; Humberto Gutie´rrez; Jaime Alvarez-Jacobs

1997-01-01

119

ThermoMechanical Processing Parameters for the INCONEL ALLOY 740  

Microsoft Academic Search

In 2000, a Cooperative Research and Development Agreement (CRADA) was undertaken between the Oak Ridge National Laboratory (ORNL) and the Special Metals Corporation (SMC) to determine the mechanical property response of the IN740 alloy to help establish thermo-mechanical processing parameters for the use of this alloy in supercritical and ultra-critical boiler tubes with the potential for other end uses. SMC

G. M. Ludtka; G. Smith

2007-01-01

120

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

121

Friction-induced work hardening of cobalt-base hardfacing deposits for hot forging tools  

Microsoft Academic Search

Cobalt-base materials are widely used as weld hardfacing deposits in hot forging industry. When the cobalt-base hardfacing alloys are deposited using the MIG welding process, the weld energy with the sequences of the welding are at least the two important variables which influence the behaviour of most hardfacing deposits in service conditions. The purpose of this work is to consider

L. Fouilland; M. El Mansori; A. Massaq

2009-01-01

122

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

2012-02-01

123

Slot Forge Furnace demonstration. Final report  

SciTech Connect

A Hague International Slot Forge Furnace was tested and installed to demonstrate a high performance energy conserving slot forge furnace in an industrial environment. This furnace was used to heat 2-1/2'' round x 31-1/8'' long bars in preparation for an upsetting operation. Each piece was heated twice, in separate operations, and upset on both ends. The Hague International Model IV Slot Forge Furnace used in the program was designed with a nominal throughput capacity of 3000 lbs/h. Due to production requirements the demonstration furnace was operated in the range of 3800 lbs/h. A base case furnace adjacent to the Hague furnace operated simultaneously. Fuel consumption and steel throughput data for both furnaces were collected and analyzed. A heating rate of 746 Btu/lb for the Hague furnace and 1620 Btu/lb for the base case furnace was demonstrated. Data demonstrated the Hague furnace's ability to save 54% of the fuel consumed by the base case furnace.

None

1981-02-01

124

Estimating demographic parameters using hidden process dynamic models.  

PubMed

Structured population models are widely used in plant and animal demographic studies to assess population dynamics. In matrix population models, populations are described with discrete classes of individuals (age, life history stage or size). To calibrate these models, longitudinal data are collected at the individual level to estimate demographic parameters. However, several sources of uncertainty can complicate parameter estimation, such as imperfect detection of individuals inherent to monitoring in the wild and uncertainty in assigning a state to an individual. Here, we show how recent statistical models can help overcome these issues. We focus on hidden process models that run two time series in parallel, one capturing the dynamics of the true states and the other consisting of observations arising from these underlying possibly unknown states. In a first case study, we illustrate hidden Markov models with an example of how to accommodate state uncertainty using Frequentist theory and maximum likelihood estimation. In a second case study, we illustrate state-space models with an example of how to estimate lifetime reproductive success despite imperfect detection, using a Bayesian framework and Markov Chain Monte Carlo simulation. Hidden process models are a promising tool as they allow population biologists to cope with process variation while simultaneously accounting for observation error. PMID:22373775

Gimenez, Olivier; Lebreton, Jean-Dominique; Gaillard, Jean-Michel; Choquet, Rémi; Pradel, Roger

2012-12-01

125

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

126

Optimizing noise control strategy in a forging workshop.  

PubMed

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

Razavi, Hamideh; Ramazanifar, Ehsan; Bagherzadeh, Jalal

2014-01-01

127

Characteristics, Process Parameters, and Inner Components of Anaerobic Bioreactors  

PubMed Central

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

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

2014-01-01

128

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.

2011-03-28

129

Exploring control parameters of two photon processes in solutions#  

PubMed Central

Two-photon microscopy depends extensively on the two-photon absorption cross-sections of biologically relevant chromophores. High repetition rate (HRR) lasers are essential in multiphoton microscopy for generating satisfactory signal to noise at low average powers. However, HRR lasers generate thermal distortions in samples even with the slightest single photon absorption. We use an optical chopper with HRR lasers to intermittently ‘blank’ irradiation and effectively minimize thermal effects to result in a femtosecond z-scan setup that precisely measures the two-photon absorption (TPA) cross-sections of chromophores. Though several experimental factors impact such TPA measurements, a systematic effort to modulate and influence TPA characteristics is yet to evolve. Here, we present the effect of several control parameters on the TPA process that are independent of chromophore characteristics for femtosecond laser pulse based measurements; and demonstrate how the femtosecond laser pulse repetition rate, chromophore environment and incident laser polarization can become effective control parameters for such nonlinear optical properties.

GOSWAMI, DEBABRATA; NAG, AMIT

2013-01-01

130

Evaluation of High Energy Rate Forged Gears with Integral Teeth.  

National Technical Information Service (NTIS)

The fatigue properties of gears forged with integral teeth were compared with those of gears machined from bar stock and gears machined from simple upset forgings. The gears tested were manufactured from both air melt and vacuum-melt 9310 steel and tested...

F. L. Parkinson

1967-01-01

131

Microfractography in failure analysis of cold forging dies  

Microsoft Academic Search

In this paper microfractographic features in fracture surfaces for tensile, fatigue, impact and three point bending of cold forging die steels with Rockwell C scale hardness number of 52–68 is presented. The emphasis is placed upon the stretched zone formation ahead of fatigue crack and the relation between the stretched zone width and fracture toughness of these cold forging die

R. Ebara; K. Takeda; Y. Ishibashi; A. Ogura; Y. Kondo; S. Hamaya

2009-01-01

132

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

133

SENSITIVITY ANALYSIS OF PROCESSING PARAMETERS BY DIRECT DIFFERENTIATION METHOD FOR LASER SURFACE HARDENING TREATMENT  

Microsoft Academic Search

The present study deals with an application of the finite element method to the sensitivity analysis of processing parameters for laser surface hardening treatment. Computing the sensitivity of temperature distributions to changes in processing parameters allows one to determine the more effective input parameters for laser surface hardening treatment. The interesting processing parameters are taken as the characteristic beam radius

S.-H. Lee; Y.-S. Yang

2001-01-01

134

The effect of hot isostatic pressing parameters on microstructure and mechanical properties of Eurofer powder HIPed material  

NASA Astrophysics Data System (ADS)

The production of reduced activation ferritic/martensitic (RAFM) steel by powder metallurgy and high isostatic pressing (HIP) offers numerous advantages for different nuclear applications. The objective of this work is to optimise the Eurofer powder HIP process in order to obtain RAFM solid HIPed steel with similar mechanical properties to those of a forged material. Starting from the forged solid Eurofer steel batch, the material is atomized and the Eurofer powder is characterized in terms of granulometry, chemical composition, surface oxides, etc. Different compaction HIP cycle parameters in the temperature range (950-1100 °C) are tested. The chemical composition of the HIPed material is comparable to the initial forged Eurofer. All the obtained materials are fully dense and the microstructure of the compacted material is well martensitic. The prior austenite grain size seems to be constant in this temperature range. The mechanical tests performed at room temperature reveal acceptable hardness, tensile and Charpy impact properties regarding the ITER specification.

Gentzbittel, J. M.; Chu, I.; Burlet, H.

2002-12-01

135

Portable computer measuring systems for automatic process parameter acquisition in garment sewing processes  

Microsoft Academic Search

A measuring system for automatic process parameter acquisition in garment sewing operations has been presented. The measuring equipment is based upon the usage of a very powerful portable notebook IBM compatible personal computer, equipped with an AD converter, measuring instruments and adequate software packages for data storing and analysis. Characteristics of measuring instruments and sensors have also been given, together

Dubravko Rogale; Zvonko Drag?evi?

1998-01-01

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

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

NASA Astrophysics Data System (ADS)

The aim of this study is to improve mixing in supercritical anti-solvent process (SAS) with impinging jets in order to form finer particles of sulfathiazole, a poorly water-soluble drug. The influence of several process parameters upon the powder characteristics is studied. Parameters are jets' velocity (0.25 m s-1 to 25.92 m s-1), molar ratio solvent/CO2 (2.5% to 20%), temperature (313 K to 343 K), pressure (10 MPa to 20 MPa) and sulfathiazole concentration in the organic solution (0.5% to 1.8%). Two solvents are used: acetone and methanol. Smaller particles with a more homogeneous morphology are obtained from acetone solutions. For the smallest jets' velocity, corresponding to a non-atomized jet, the stable polymorphic form is obtained, pure or in mixture. At this velocity, pressure is the most influential parameter controlling the polymorphic nature of the powder formed. The pure stable polymorph is formed at 20 MPa. Concerning the particle size, the most influential parameters are temperature and sulfathiazole concentration. The use of impinging jets with different process parameters allows the crystallization of four polymorphs among the five known, and particle sizes are varied. This work demonstrates the studied device ability of the polymorph and the size control. A comparison with the classical SAS process shows that particle size, size distribution and morphology of particles crystallized with impinging jets are different from the ones obtained with classical SAS introduction device in similar operating conditions. Mean particle sizes are significantly smaller and size distributions are narrower with impinging jets device.

Careno, Stéphanie; Boutin, Olivier; Badens, Elisabeth

2012-03-01

138

FMCW-radar Signal Processing and Parameter Estimation.  

National Technical Information Service (NTIS)

This report concerns the development of a real time algorithm to estimate the path parameters of a threat target, for protection of military hardware. The target is assumed to move in a straight line with parameters pass distance, pass time and target vel...

R. Aljasmi

2002-01-01

139

Technical bases for precipitate hydrolysis process operating parameters  

SciTech Connect

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

Bannochie, C.J.

1992-10-05

140

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

141

Deformation characteristics of isothermally forged UDIMET 720 nickel-base superalloy  

Microsoft Academic Search

The hot deformation behavior of nickel-base superalloy UDIMET 720 in solution-treated conditions, simulating the forging process\\u000a of the alloy, was studied using hot compression experiments. Specimens were deformed in the temperature range of 1000 C to\\u000a 1175 C with strain rates of 10?3 to 1 s?1 and total strain of 0.8. Below 1100 C, all specimens showed flow localization as

H. Monajati; A. K. Taheri; M. Jahazi; S. Yue

2005-01-01

142

Forming of hollow gear-shafts with pressure-assisted injection forging (PAIF)  

Microsoft Academic Search

Hollow gear-shafts were formed with a radial extrusion configuration, which involves the use of polymers as the pressurising media—pressure-assisted injection forging (PAIF). The process was qualified with definition of the forming-limit diagrams established with reference to three typical loading paths (histories of the injection and pressurisation). Forming was effected with the qualified procedures and pressurizing media. The results demonstrated feasibility

Yanling Ma; Yi Qin; Raj Balendra

2005-01-01

143

SHIFTS RECOGNITION IN CORRELATED MANUFACTURING PROCESS PARAMETERS USING NEURAL NETWORK  

Microsoft Academic Search

Because of the existence of the autocorrelation in the data series, traditional statistical process control (SPC) techniques of control charting are not applicable in many process industries. Therefore how to reduce the process variability obtained through the use of SPC techniques has been discussed for years in process industries. Techniques are needed to serve the same functions as SPC control

Chih-Chou Chiu; Ming-Hsien Yang

2001-01-01

144

Optimization research of process parameters for Laser Direct Rapid Forming metal parts based on genetic algorithm  

Microsoft Academic Search

The optimization research of process parameters for Laser Direct Rapid Forming (LDRF) metal parts, is a research focus of rapid prototyping technology. The article discussed in detail for solving the optimum process parameters of LDRF technology for the selection approach of strategy of genetic algorithm, the quantitative relationship model was established between process parameters of forming pieces and the part

Wang Jianbin; Chen binghuang

2010-01-01

145

Technical bases for precipitate hydrolysis process operating parameters  

SciTech Connect

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

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

1992-11-09

146

Technical bases for precipitate hydrolysis process operating parameters. Revision 1  

SciTech Connect

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

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

1992-11-09

147

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.

2014-05-01

148

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

149

Development of Large Size Fully Automated Forging Press Line.  

National Technical Information Service (NTIS)

Large parts with such complicated configurations as steering knuckle, call for a higher degree of rigidity than any commercially available standard type automated forging presses can meet. Therefore, it is vital to increase the rigidity of the stamping ma...

I. Mizutani T. Karata K. Takebayashi H. Nakamura

1988-01-01

150

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

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

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

151

A marvel of medieval Indian metallurgy: Thanjavur's forge-welded iron cannon  

NASA Astrophysics Data System (ADS)

In this article, metallurgical aspects of a 17th century forge-welded iron cannon at Thanjavur are addressed, including an analysis of manufacturing methodology based on careful observation of its constructional details. Microstructural examination of iron from the cannon reveals that the iron was extracted from ore by the direct process. Thus, the cannon was fabricated by forge welding and not by casting. Electrochemical polarization studies indicate that the corrosion rate of the cannon iron can be compared to that of 0.05% carbon mild steel under complete immersion conditions. However, the atmospheric corrosion resistance of the cannon is far superior to that of modern steel and can be attributed to the formation of an adherent protective passive film. It is concluded that this cannon constitutes a marvel of medieval Indian metallurgical skill.

Balasubramaniam, R.; Saxena, A.; Anantharaman, Tanjore R.; Reguer, S.; Dillmann, P.

2004-01-01

152

Reducing residual stress in 2014 aluminium alloy die forgings  

Microsoft Academic Search

Closed die forgings manufactured from 2014 aluminium alloys have been subject to both standard and non-standard heat treatments in order to reduce the as-quenched residual stress magnitudes. Warm water (60°C) and boiling water quenches are investigated. The influence of changing the surface finish of the forgings during boiling water quenching on the mechanical properties and residual stress has also been

D. A. Tanner; J. S. Robinson

2008-01-01

153

A study of selected parameters in solid propellant processing  

NASA Technical Reports Server (NTRS)

A propellant processing study to identify and control unplanned variation in composite solid propellant properties has shown that burning rate increases with process mixing but is not sensitve to process temperature. Different vertical propellant mixes of the same type were shown to provide different conditions of mixing at the pot wall because of differences in gearing, sometimes resulting in a stagnant wall film. Poor propellant produced in the stagnant wall film was attributed to poor mixing because of viscosity effects and wall film geometry. A control strategy based on briefly heating the wall was demonstrated. The study showed the need for improved process controls, good process instruments, and good propellant testing.

Mckay, R. A.

1986-01-01

154

Optimisation of processing parameters in laser sintering of metallic powders  

Microsoft Academic Search

Optimisation of laser sintering of submicron metal powders has been studied in connection with unsteady heat transfer in a porous powder layer under conditions of rapid phase transformations. The heating rate, cooling rate and depth of the sintered layer are estimated after analysis of geometrical characteristics of the metallic powder. The computer simulation revealed that the control parameters of the

G A Gordeev; V E Ankudinov; M D Krivilyov; E V Kharanzhevskiy

2012-01-01

155

Signal Processing for Longitudinal Parameters of the Tevatron Beam.  

National Technical Information Service (NTIS)

We describe the system known as the Tevatron SBD which is used to provide information on the longitudinal parameters of coalesced beam bunches in the Tevatron. The system has been upgraded over the past year with a new digitizer and improved software. The...

S. Pordes, J. Crisp, B. Fellenz, R. Flora, A. Para, A. V. Tollestrup

2005-01-01

156

Computer simulation to predict stresses, working pressures and deformation modes in incremental forging of spur gear forms  

Microsoft Academic Search

Incremental upset-forging of spur gear forms around the surfaces of short length axisymmetric billets of different length to diameter ratios is simulated using a free body equilibrium approach based on the slab method of analysis. The mechanics of the process are analysed employing both the mixed cylindrical and Cartesian coordinate systems as well as an entirely cylindrical coordinate system. The

N. R. Chitkara; M. A. Bhutta

1996-01-01

157

Production of bimetallic joints between gray cast iron and steel by forging and explosion with subsequent thermal cycling  

Microsoft Academic Search

The possibility of producing strong bimetallic joints with interaction between different compositions of gray cast irons, which contain different shapes of graphite and which have a ferritic or austenitic matrix, and carbon steel is investigated. Elementary processes that take place in the vicinity of the free contacting surfaces of the metals during forging, explosion, and thermal cycling are studied. Treatment

Yu. N. Taran; V. Ya. Slobodskoi; S. I. Gubenko; V. V. Sobolev; O. I. Konobritskaya

1991-01-01

158

Optimization of green sand casting process parameters by using Taguchi’s method  

Microsoft Academic Search

This paper analyses various significant process parameters of the green sand casting process. An attempt has been made to obtain optimal settings of the green sand casting process in order to yield the optimum quality characteristics of the spheroidal graphite (SG) cast iron rigid coupling castings. The process parameters considered are: green strength, moisture content, permeability and mould hardness. The

S. Guharaja; A. Noorul Haq; K. M. Karuppannan

2006-01-01

159

Process parameters influence on friction coefficient in sheet forming operations  

Microsoft Academic Search

In conventional sheet forming processes, such as stamping or drawing, significant contact phenomena take place between workpiece\\u000a and die surfaces. Especially, relative motion and normal loads generate friction which influences some aspects of processes\\u000a such as material flow, tools wear and life and total force needed to complete the process. In the current paper an experimental\\u000a test campaign has been

E. Ceretti; A. Fiorentino; C. Giardini

2008-01-01

160

Upstream processes in antibody production: Evaluation of critical parameters  

Microsoft Academic Search

The demand for monoclonal antibody for therapeutic and diagnostic applications is rising constantly which puts up a need to bring down the cost of its production. In this context it becomes a prerequisite to improve the efficiency of the existing processes used for monoclonal antibody production. This review describes various upstream processes used for monoclonal antibody production and evaluates critical

Era Jain; Ashok Kumar

2008-01-01

161

Load Bearing Response of HR Molded Foam as a Function of Processing and Testing Parameters  

Microsoft Academic Search

There are critical processing and testing parameters which have major impacts upon the apparent firmness of HR molded polyurethane foam. Inadequate control of these parameters hinders the ability of the molder to meet narrow IFD specifications. This paper addresses five of these parameters and defines model equations which are useful in predicting load response to specific control parameters. In addition,

K. D. Cavender; M. R. Kinkelaar

1996-01-01

162

Signal processing for longitudinal parameters of the Tevatron beam  

SciTech Connect

We describe the system known as the Tevatron SBD [1] which is used to provide information on the longitudinal parameters of coalesced beam bunches in the Tevatron. The system has been upgraded over the past year with a new digitizer and improved software. The quantities provided for each proton and antiproton bunch include the intensity, the longitudinal bunch profile, the timing of the bunch with respect to the low-level RF, the momentum spread and the longitudinal emittance. The system is capable of 2 Hz operation and is run at 1 Hz.

Pordes, S.; Crisp, J.; Fellenz, B.; Flora, R.; Para, A.; Tollestrup, A.V.; /Fermilab

2005-05-01

163

On Functional Central Limit Theorems for Certain Continuous Time Parameter Stochastic Processes.  

National Technical Information Service (NTIS)

Weak invariance principles for certain continuous time parameter stochastic processes are considered. In particular, the case of continuous time parameter martingale and reverse martingale sequences are treated elaborately and the weak convergence in sup-...

P. K. Sen Y. Tsong

1978-01-01

164

Reservoir and operational parameters influence in SAGD process  

Microsoft Academic Search

Thermal processes are used to improved heavy oil recovery, and they could be based on the steam injection, i.e. cyclic or continuous injection. The continuous injection has many variations, and has been studied both theoretically and experimentally (in pilot projects and in full field applications). One of the technologies that is being studied is one variation of the continuous injection,

J. L. M. Barillas; T DUTRAJR; W. Mata

2006-01-01

165

Low-pressure die casting of magnesium alloy AM50: Response to process parameters  

Microsoft Academic Search

Low-pressure die casting (LPDC) process has been successfully used to produce sound magnesium alloy AM50 castings. The influence of process parameters: filling time, pressure holding time, die temperature, holding pressure and casting temperature, on the mechanical properties, microstructure and density of LPDC castings were studied. The optimal process parameters for LPDC casting have been experimentally determined as follows: filling time

Penghuai Fu; Alan A. Luo; Haiyan Jiang; Liming Peng; Yandong Yu; Chunquan Zhai; Anil K. Sachdev

2008-01-01

166

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

167

Drell-Yan process and factorization in impact parameter space  

SciTech Connect

The cross section for Drell-Yan pair production in the limit of small x{sub target} is derived in the rest frame of the target hadron. Our calculation is based on the fundamental quantity {sigma}({rho}), the cross section for the scattering of a q{bar q} pair with fixed transverse separation {rho} off a hadronic target. As in deep inelastic scattering the result can be given in terms of integrals of {sigma}({rho}). This is consistent with well-known factorization theorems and also relates higher-twist terms in both processes. An analysis of the angular distribution of the produced lepton shows that additional integrals of {sigma}({rho}) can be obtained in the Drell-Yan process, which are not measurable in inclusive deep inelastic scattering. {copyright} {ital 1997} {ital The American Physical Society}

Brodsky, S.J.; Hebecker, A.; Quack, E. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)] [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)

1997-03-01

168

Influence of daughter radionuclides on Purex-process parameters  

Microsoft Academic Search

Experimental and calculated data are presented which concern the limiting influence of239Np,237U,233Pa,234Th,228Th (with daughter radionuclides) on the final decontamination of uranium, plutonium and neptunium from -emitters in Purex-process for NPP fuel reprocessing. It was found, in particular, that in the investigated flowsheet228Th follows neptunium(IV) and233Pa accompanies plutonium. The influence of accumulated daughter -emitters on ionization characteristics of end products in

B. Ya. Zilberman; V. M. Mosyazh; V. A. Starchenko

1990-01-01

169

Geomechanical Parameters in Fracturing Process of Layered Rocks  

NASA Astrophysics Data System (ADS)

Hydraulic fracturing is crucial to geothermal and hydrocarbon recovery. Predicting performance based on rock characteristics (micro and macro) is essential to effective stimulation. We studied two extreme rock types: 1) Lyons sandstone, a brittle, low porosity, low permeability, weakly anisotropic material and 2) pyrophyllite, a strongly anisotropic metamorphic rock similar chemically and mechanically to shale, having extremely low porosity and permeability. Mineralogy, porosity, permeability, mercury capillary pressure, grain size, ?-CT imaging and elastic anisotropy analysis describe these rocks. Brazilian disk tests were carried to observe the fracture initiation and propagation under tension. Fracture propagation velocity is measured using a high speed digital camera. Strain gauges and acoustic emission (AE) sensors recorded deformation leading to and during failure. SEM imaging and surface profilometry were used to study the post-failure fracture systems and failed surface topology. The fracture process zone (FPZ) is mapped and evaluated using a mosaic of stitched SEM images. The fracture permeability was measured as a function of effective stress and compared to fracture permeability models. The effect of anisotropy on fracturing (Mode I and Mode II fractures) was also investigated rotating the fabric direction of the tested disks relative to the loading axis through increments of 15 degrees. Results indicate differences in fracturing process of these two rock types. Pyrophyllite displays a localized ductile behavior in the process zone resulting in a narrower fracture with a higher propagation velocity and far less AE activity. Pyrophyllite shows 70 % higher tensile strength compared to Lyons sandstone even though it becomes ductile at much lower pressures. The sandstone shows a wide brittle fracture with larger FPZ and better permeability at elevated effective pressures. The greater number of AE activity associated with higher energy events confirms the statistical analysis of microcracks formation inferred from SEM mosaics. The brittleness leads also to the dependence of failure on fabric dependent tensile strength. We observe twice as much Mode II fracturing (layer activation) at lower stress levels for Lyons sandstone. The rock microstructure, lamination, and brittleness control the break down pressure. They also influence the FPZ and laminations reactivation which affect the fracture conductivity and stimulated reservoir volume (SRV).

Mighani, S.; Sondergeld, C. H.; Rai, C. S.

2013-12-01

170

Surface-based IRST: a selection process for sensor parameter values  

Microsoft Academic Search

The parameter values for a Navy's IRST (infrared search and track) sensor are determined by (1) the operational requirements, (2) the available best technology, and (3) past experience with IRST system design. The selection process for the parameter values is illustrated by use of a set of operational requirements representative of the North Sea. Initial values of the optics parameters

Bjorn F. Andresen; Oded Ben-David; Shlomo Glazer; Shmuel Roth; Baruch Levy

1997-01-01

171

Modelling of Deformation and Microstructural Changes in P/M Rene 95 under Isothermal Forging Conditions.  

National Technical Information Service (NTIS)

The changes in microstructure induced by forging and their influence on flow strength in hot isostatically pressed P/M Rene 95 as revealed by constant true strain compression tests under simulated isothermal forging conditions are discussed. Results are p...

O. Alniak D. D. Morphy T. Terada A. K. Koul J. Immarigeon

1988-01-01

172

A study on the micro-formability of Al 5083 superplastic alloy using micro-forging method  

Microsoft Academic Search

Micro-formability of superplastic Al 5083 alloy as a candidate material for micro-forming was investigated by varying the forming parameters such as time, load and temperature. Micro-forging machine and Si micro-dies with V-groove were employed for micro-forming test. Micro-formability was estimated by comparing Rf values (=Af\\/Ag), where Ag is cross-sectional area of V-groove, and Af the filled area by micro-formed sample.

S. G. Kang; Y. S. Na; K. Y. Park; J. E. Jeon; S. C. Son; J. H. Lee

2007-01-01

173

Thermal analysis of laser surface transformation hardening—optimization of process parameters  

Microsoft Academic Search

This paper deals with the optimization of process parameters for maximum productivity (given by the product of scanning velocity and cross feed) in laser transformation hardening. The process parameters considered are laser beam power, P; laser beam diameter, Db; and the heat intensity distribution, namely, normal, bimodal, or uniform. A thermal analysis of the laser surface transformation hardening of gears

R. Komanduri; Z. B. Hou

2004-01-01

174

Evaluation of spherically invariant random process parameters as discriminators for speaker verification  

Microsoft Academic Search

In this work, we are interested in the potential use of spherically invariant random processes (SIRPs), described by two parameters, for speaker identification. These random processes have been shown to be a more statistically-accurate model for speech than Laplace and Gamma probability density functions. Computation of the two SIRP parameters is fast and simple and storage requirements are obviously small.

Joseph San Filippo; Phillip DeLeon

2004-01-01

175

Automatization Of The Control Technological Processes Of Optical Fiber Components Parameters  

Microsoft Academic Search

Object of researches are the control processes of optical fiber components parameters. The purpose of researches is development of the theory and methods bases which allow solving of the scientific -applied problem of the control processes automation of constructive -technological parameters in manufacture, installation and exploitation of passive optical fiber components, to create of theoretical and practical base for modules

A. Filipenko; I. Nevludov; O. Sicheva

2007-01-01

176

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

177

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

NASA Astrophysics Data System (ADS)

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

Lyphout, Christophe; Nylén, Per; Östergren, Lars

2011-01-01

178

Order formation processes of complex systems including different parity order parameters  

NASA Astrophysics Data System (ADS)

In the present study, we focus on the parity of the order parameters and clarify the order formation process in a system including two order parameters. Each order parameter shows different parity under a gauge transformation, namely even and odd order parameters. For example, in a spin-glass model, the even order parameter corresponds to the spin-glass order parameter while the odd one corresponds to the magnetization. We introduce phenomenologically a set of Langevin equations to express the ordering process under a white Gaussian noise. Using two kinds of Fokker–Planck equations, we analyze the order formation process and the entropy production. Furthermore, we show the noise dependence of the onset time.

Hashizume, Yoichiro; Suzuki, Masuo; Okamura, Soichiro

2014-06-01

179

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

180

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

181

Forging Consensus for Implementing Youth Socialization Policy in Northwest China  

ERIC Educational Resources Information Center

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

Fairbrother, Gregory P.

2011-01-01

182

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

183

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

184

Valley Forge National Historical Park Natural Resource Condition Assessment.  

National Technical Information Service (NTIS)

Valley Forge NHP is a member of the Mid-Atlantic Inventory and Monitoring Network, one of 32 such networks developed and operated by the National Park Service throughout the country. These networks are charged with coordinating the inventory and long-term...

J. Kozak K. Brubaker L. S. Sherwin M. May P. Sharpe

2013-01-01

185

Anisotropic Embrittlement in High-Hardness ESR 4340 Steel Forgings.  

National Technical Information Service (NTIS)

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...

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

1982-01-01

186

Forging New Global Alliances: Emerging Markets and Advanced Economies  

Microsoft Academic Search

Forging new global alliances or new legal and institutional frameworks through international cooperation could help solve the 2007–2009 financial crisis by addressing the most vulnerable aspects of the current financial system and infrastructure. These aspects are liquidity, which is at the heart of the stability of the financial system; trust and transparency, with better disclosure of banks’ institutional arrangements for

Ceslav Ciobanu; David Bejou

2009-01-01

187

Effective Tooling Designs for Production of Precision Forgings.  

National Technical Information Service (NTIS)

The aim of the two-phase program is to demonstrate that nonsymmetric rib-and-web type configurations can be hot forged to precision dimensions with better die life through the use of reinforcing components surrounding the die inserts. Efforts consisted of...

F. A. Simonen J. R. Becker J. R. Douglas

1972-01-01

188

Electronic Portfolios in Teacher Education: Forging a Middle Ground  

ERIC Educational Resources Information Center

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

Strudler, Neal; Wetzel, Keith

2012-01-01

189

Effect of process parameters on friction stir welding of aluminum alloy 2219-T87  

Microsoft Academic Search

In this work, successful friction stir welding of aluminum alloy 2219 using an adapted milling machine is reported. The downward\\u000a or forging force was found to be dependent upon shoulder diameter and rotational speed whereas longitudinal or welding force\\u000a on welding speed and pin diameter. Tensile strength of welds was significantly affected by welding speed and shoulder diameter\\u000a whereas welding

Kanwer S. Arora; Sunil Pandey; Michael Schaper; Rajneesh Kumar

2010-01-01

190

Parameter estimation for abrasive water jet machining process using neural networks  

Microsoft Academic Search

The abrasive water jet machining process, a material removal process, uses a high velocity jet of water and an abrasive particle\\u000a mixture. The estimation of appropriate values of the process parameters is an essential step toward an effective process performance.\\u000a This has led to the development of numerous mathematical and empirical models. However, the complexity of the process confines\\u000a the

Pratik J. Parikh; Sarah S. Lam

2009-01-01

191

Nonadherence to the isochrony principle in forged signatures.  

PubMed

Highly programmed skilled movements are executed in such a way that their kinematic features adhere to certain rules referred to as minimization principles. One such principle is the isochrony principle, which states that the duration of voluntary movement remains approximately constant across a range of movement distances; that is, movement duration is independent of movement extent. The concept of isochrony suggests that some information stored in the motor program is constant, thus reducing the storage demands of the program. The aim of the present study was to examine whether forged signatures can be distinguished from genuine signatures on the basis of isochrony kinematics. Sixty writers were asked to write their own signatures and to forge model signatures representing three different writing styles: text-based, stylized, and mixed. All signatures were digitized to enable high precision dynamic analyses of stroke kinematics. Vertical stroke duration and absolute amplitude were measured for each pen stroke of the signatures using MovAlyzeR(®) software. Slope coefficients derived from simple regression models of the relationship between stroke duration and amplitude served as our measure of isochrony. The slope coefficient reflects the degree to which stroke duration increases in relation to stroke amplitude. Higher coefficients indicate greater increases in stroke duration for a given stroke amplitude and thus violate the isochrony principle. We hypothesized that the duration-amplitude coefficients for forged signatures would be significantly greater than for genuine signatures suggesting non-adherence to the isochrony principle. Results indicated that regardless of the style of the writer, genuine signatures were associated with low slope coefficients Pen strokes forming forged signatures had significantly greater duration-amplitude slope coefficients than genuine signatures. These findings suggest that when forging signatures, writers execute pen movements having steeper duration-amplitude relationships than for genuine signatures. PMID:23084659

Caligiuri, Michael P; Mohammed, Linton A; Found, Bryan; Rogers, Doug

2012-11-30

192

Development of an integrated neural network system for prediction of process parameters in metal injection moulding  

Microsoft Academic Search

In this present work attempts have been made to develop an integrated neural network system for prediction of process parameters such as injection pressure and injection time in metal injection moulding (MIM) process. The current system has been developed by integrating the different aspects of MIM process. The aspects that are addressed in this system are the physical model of

Prasad K. D. V Yarlagadda

2002-01-01

193

An IRT Model with a Parameter-Driven Process for Change  

Microsoft Academic Search

An IRT model with a parameter-driven process for change is proposed. Quantitative differences between persons are taken into\\u000a account by a continuous latent variable, as in common IRT models. In addition, qualitative interindividual differences and\\u000a autodependencies are accounted for by assuming within-subject variability with respect to the parameters of the IRT model.\\u000a In particular, the parameters of the IRT model

Frank Rijmen; Paul De Boeck

2005-01-01

194

EUV resist simulation based on process parameters of pattern formation reaction  

NASA Astrophysics Data System (ADS)

We simulated the process parameters of a pattern formation reaction that included during-the-exposure and post exposure bake (PEB) processes using an originally developed simulator. From the simulation results, the relationship between process parameters of pattern formation reaction and quencher concentration has been clarified. Moreover, we simulated the present target process parameters of extreme ultraviolet (EUV) resist for breaking the RLS trade-off. In this simulation, the process parameters were calculated from lithographic results (sensitivity, LWR, and CD) using real SEM images. This methodology was used to determine the process parameters required to break the RLS trade-off to obtain the required lithographic target of the EUV resist. We simulated the present lithography performance target using the process parameters of pattern formation reactions. These simulation results showed that a large reaction radius is necessary to break the RLS trade-off. Furthermore, we confirmed that increasing the PEB temperature leads to an improvement in the reaction radius. However, there is a discrepancy between the target radius and the controllable range of reaction radius that can be obtained by varying the PEB temperature.

Sugie, Norihiko; Itani, Toshiro; Kozawa, Takahiro

2014-04-01

195

Numerical self-regulation of time-dependent parameters in tube hydroforming processes  

NASA Astrophysics Data System (ADS)

Large expansion in tube hydroforming processes is only achievable with proper combination of inner pressure and axial compression applied on the tube. To avoid bursting in T-branches additional radial force controlled punches are necessary. A suboptimal layout of the corresponding time-dependent parameters results in wrinkling or ruptures. Successful tube hydroforming processes demand optimization of the pressure-time diagram as well as the prescribed displacement or force schedules of the forming tools, which is by no means an easy task. Most current processes are based on the trial and error method and are usually influenced by some random factors. A new algorithm to automatically optimize the process parameters in the tube hydroforming processes is presented in this work. This algorithm combines the FEM process calculation with the parameter determination according to the basic physical principles. The coupled PID-control is established.

Holecek, M.; Hora, P.

2005-08-01

196

S?S Process Location Parameter Adaptive Estimator Based on Data Censoring  

Microsoft Academic Search

The task of location parameter estimation by means of adaptive censored procedure in S?S noise environment is considered. Based on the carried out research it is proposed to use the percentile coefficient of kurtosis and median absolute deviation as parameters able to describe processes with S?S pdf in case of absence of a priori knowledge about its statistical characteristics. The

A. A. Roenko; V. V. Lukin; I. Djurovic

2007-01-01

197

A distributed probabilistic system for adaptive regulation of image processing parameters  

Microsoft Academic Search

A distributed optimization framework and its application to the regulation of the behavior of a network of interacting image processing algorithms are presented. The algorithm parameters used to regulate information extraction are explicitly represented as state variables associated with all network nodes. Nodes are also provided with message-passing procedures to represent dependences between parameter settings at adjacent levels. The regulation

V. Morino; G. L. Foresti; C. S. Regazzoni

1996-01-01

198

Preliminary Evaluation of an F100 Engine Parameter Estimation Process Using Flight Data.  

National Technical Information Service (NTIS)

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 ...

T. A. Maine G. B. Gilyard H. H. Lambert

1990-01-01

199

Influence of processing parameters on nanomaterials synthesis efficiency by a carbothermal reduction process  

Microsoft Academic Search

In this work, the influence of synthesis parameters on the synthesis efficiency of tin oxide nanomaterials was studied by\\u000a using the carbothermal reduction method in a sealed tube furnace. The parameters were the starting material, temperature and\\u000a time of synthesis as well as the gas flux. The starting material was tin dioxide mixed with carbon black in a molar proportion

Pedro Henrique Suman; Marcelo Ornaghi Orlandi

2011-01-01

200

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

201

An integrated system for setting the optimal parameters in IC chip-package wire bonding processes  

Microsoft Academic Search

The wire bonding process is the key process in an IC chip-package. It is an urgent problem for IC chip-package industry to\\u000a improve the wire bonding process capability. In this study, an integrated system is proposed to identify and control parameters\\u000a in the wire bonding process in order to achieve high level performance and quality. First, an experimental design with

Tung-Hsu Hou; Shyh-Huei Chen; Tzu-Yu Lin; Kun-Ming Huang

2006-01-01

202

Optimization of material and process parameter for minimizing defect in implementation of MFHM process  

Microsoft Academic Search

Silicon-containing material has recently attracted attention as new hard mask material. We have studied the applicability of MFHM (Multi-Functional Hard Mask)\\/SOC (Spin on Carbon) materials as an alternative to the BARC\\/SiON\\/ amorphous carbon (a-C) process. This process is very useful in terms of cost reduction and process simplicity compared to a-C process. Evaluation results have showed good lithographic and etch

Kilyoung Lee; Junggun Heo; Keundo Ban; Hyungsuk Seo; Geunsu Lee; Wonkyu Kim; Junhee Cho; Junhyeub Sun; Sungkwon Lee; Cheolkyu Bok; Seungchan Moon; Jinwoong Kim

2007-01-01

203

Friction-stir welding of AA 2198 butt joints: mechanical characterization of the process and of the welds through DOE analysis  

Microsoft Academic Search

In this study, rolled plates of AA 2198 T3 aluminium alloy are friction-stir welded in butt configuration varying two fundamental\\u000a process parameters: rotational and welding speeds. Two sets of empirical models based on regression analysis are developed.\\u000a The first one predicts the stationary values of the in-plane and downwards forging welding forces in dependence of the process\\u000a parameters under investigation.

Ciro Bitondo; Umberto Prisco; Antonino Squilace; Pasquale Buonadonna; Gennaro Dionoro

2011-01-01

204

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

205

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

206

Forging of Refractory Metals in a Vacuum.  

National Technical Information Service (NTIS)

The creation of a vacuum or a neutral environment in the process of heating and processing ingots is the most progressive procedure for protecting refractory metals against oxidization and gas saturation. The advantages of this method are the creation of ...

S. B. Pevzner N. I. Korneev I. G. Skugarev A. S. Tugushev Y. V. Malashenko

1967-01-01

207

Gaussian process inference for estimating pharmacokinetic parameters of dynamic contrast-enhanced MR images.  

PubMed

In this paper, we propose a new pharmacokinetic model for parameter estimation of dynamic contrast-enhanced (DCE) MRI by using Gaussian process inference. Our model is based on the Tofts dual-compartment model for the description of tracer kinetics and the observed time series from DCE-MRI is treated as a Gaussian stochastic process. The parameter estimation is done through a maximum likelihood approach and we propose a variant of the coordinate descent method to solve this likelihood maximization problem. The new model was shown to outperform a baseline method on simulated data. Parametric maps generated on prostate DCE data with the new model also provided better enhancement of tumors, lower intensity on false positives, and better boundary delineation when compared with the baseline method. New statistical parameter maps from the process model were also found to be informative, particularly when paired with the PK parameter maps. PMID:23286178

Wang, Shijun; Liu, Peter; Turkbey, Baris; Choyke, Peter; Pinto, Peter; Summers, Ronald M

2012-01-01

208

Gaussian Process Inference for Estimating Pharmacokinetic Parameters of Dynamic Contrast-Enhanced MR Images  

PubMed Central

In this paper, we propose a new pharmacokinetic model for parameter estimation of dynamic contrast-enhanced (DCE) MRI by using Gaussian process inference. Our model is based on the Tofts dual-compartment model for the description of tracer kinetics and the observed time series from DCE-MRI is treated as a Gaussian stochastic process. The parameter estimation is done through a maximum likelihood approach and we propose a variant of the coordinate descent method to solve this likelihood maximization problem. The new model was shown to outperform a baseline method on simulated data. Parametric maps generated on prostate DCE data with the new model also provided better enhancement of tumors, lower intensity on false positives, and better boundary delineation when compared with the baseline method. New statistical parameter maps from the process model were also found to be informative, particularly when paired with the PK parameter maps.

Wang, Shijun; Liu, Peter; Turkbey, Baris; Choyke, Peter; Pinto, Peter; Summers, Ronald M.

2014-01-01

209

Modelling And Optimization Of Process Parameters For Tig Welding Of Aluminium-65032 Using Response Surface Methodology  

NASA Astrophysics Data System (ADS)

Tungsten inert gas welding is one of the widely used techniques for joining ferrous and non ferrous metals. TIG welding offers several advantages like joining of dissimilar metals, low heat affected zone, absence of slag etc. The aim of this paper is to investigate the effect of TIG welding process parameters on welding of Aluminium-65032. Response Surface Methodology was used to conduct the experiments. The parameters selected for controlling the process are welding speed, current and gas flow rate. Strength of welded joints were tested by a UTM. Percent elongation was also calculated to evaluate the ductility of the welded joint. From the results of the experiments, mathematical models have been developed to study the effect of process parameters on tensile strength and percent elongation. Optimization was done to find optimum welding conditions to maximize tensile strength and percent elongation of welded specimen. Confirmation tests were also conducted to validate the optimum parameter settings.

Palani, P. K.; Saju, M.

2013-03-01

210

A neural network system for the prediction of process parameters in pressure die casting  

Microsoft Academic Search

In this work an artificial intelligent neural network system is developed to generate the process parameters for the pressure die casting process. The scope of this work includes analysing a physical model of the pressure die casting filling stage based on the governing equations of die cavity filling, and the collection of feasible casting data for the training of the

Prasad K. D. V. Yarlagadda; Eric Cheng Wei Chiang

1999-01-01

211

Analysis of process parameters for steady operations in methane mild combustion technology  

Microsoft Academic Search

The main process parameters affecting combustors of all types are analyzed in the range of interest concerning mild combustion processes for methane oxidation. They are studied by means of direct comparison between experimental measurements made in a Jet Stirred Flow Reactor and numerical predictions based on a kinetic scheme developed for general use. Wide ranges of both inlet temperature (875–1275K)

M. de Joannon; A. Cavaliere; T Faravelli; E. Ranzi; P. Sabia; A. Tregrossi

2005-01-01

212

Effects of laser sintering processing parameters on the microstructure and densification of iron powder  

Microsoft Academic Search

The densification behavior and the attendant microstructural features of iron powder processed by direct laser sintering were investigated. The effects of processing parameters such as laser power, scan rate, scan line spacing, thickness of layer, scanning geometry and sintering atmosphere were studied. A specific energy input (?) was defined using the “energy conservation” rule to explore the effects of the

A Simchi; H Pohl

2003-01-01

213

Optimization of pulsed TIG welding process parameters on mechanical properties of AA 5456 Aluminum alloy weldments  

Microsoft Academic Search

The present work pertains to the improvement of mechanical properties of AA 5456 Aluminum alloy welds through pulsed tungsten inert gas (TIG) welding process. Taguchi method was employed to optimize the pulsed TIG welding process parameters of AA 5456 Aluminum alloy welds for increasing the mechanical properties. Regression models were developed. Analysis of variance was employed to check the adequacy

A. Kumar; S. Sundarrajan

2009-01-01

214

Numerical studies on controlling of process parameters in friction stir welding  

Microsoft Academic Search

A thermo-mechanical model is developed to predict the material deformations and temperature histories in the friction stir welding (FSW) process. Based on this model, the effects of the welding parameters on temperatures and material behaviors are investigated. Numerical results indicate that the maximum temperature in the FSW process can be increased with the increase of the rotating speed. The increase

Z. Zhang; H. W. Zhang

2009-01-01

215

Influence of Cell Support and Operating Parameters on the Competitiveness of High-Temperature Electrolysis Process  

Microsoft Academic Search

This work focuses on hydrogen production by high-temperature electrolysis and the influence of operating parameters for cathode- or electrolyte-supported cells, used to build the electrolyzer, on the process competitiveness. The rigorous modeling of the electrical and thermal behavior of planar cells was performed and integrated into our program to estimate the hydrogen production cost, accounting process investment, and operation costs.

R. Rivera-Tinoco; C. Bouallou

2010-01-01

216

JOINT ESTIMATION OF STATE VARIABLES AND KINETICS PARAMETERS OF A DENITRIFICATION PROCESS  

Microsoft Academic Search

This work was a contribution to the attempts aiming to solve the problems of estimation in biotechnological processes. These problems are related to the difficulty of on-line measurements of biological variables and to the fact that bioreactors are nonlinear time-varying processes with parameters uncertainties. For overcoming measurement difficulties, we proposed an adaptive estimation algorithm. This estimator is a combination of

KARIM DAHECH; TARAK DAMAK; AHMED TOUMI

217

Effect of microfabrication processes on surface roughness parameters of silicon surfaces  

Microsoft Academic Search

Surface roughness parameters affect the real area of contact and hence the friction in micro\\/nanoscale systems. Few studies have addressed the interplay between surface roughness of processed surfaces using prevalent microfabrication processes and their anticipated tribological behavior. In this paper, the effects of different etchants on the surface roughness of a Si (100) surface were investigated using atomic force microscopy.

Sharath Chandrasekaran; Sriram Sundararajan

2004-01-01

218

Improved electroless process of copper coating ceramics. 1. Some parameters of coating glass substrates  

Microsoft Academic Search

The shortcomings of the available electroless processes, such as scarcity of information on the controlling parameters, bath\\u000a instability, poor film adhesivity and film contamination are reported. The process described in this paper differs from the\\u000a conventional process not only in the raw materials used but also in the operational details. The criteria of choice of such\\u000a materials are discussed. Further,

L. G. Bhatgadde; S. Mahapatra

1980-01-01

219

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

220

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

221

Applications and perspectives of multi-parameter flow cytometry to microbial biofuels production processes.  

PubMed

Conventional microbiology methods used to monitor microbial biofuels production are based on off-line analyses. The analyses are, unfortunately, insufficient for bioprocess optimization. Real time process control strategies, such as flow cytometry (FC), can be used to monitor bioprocess development (at-line) by providing single cell information that improves process model formulation and validation. This paper reviews the current uses and potential applications of FC in biodiesel, bioethanol, biomethane, biohydrogen and fuel cell processes. By highlighting the inherent accuracy and robustness of the technique for a range of biofuel processing parameters, more robust monitoring and control may be implemented to enhance process efficiency. PMID:22257766

da Silva, Teresa Lopes; Roseiro, José Carlos; Reis, Alberto

2012-04-01

222

Multi-objective optimization of forming parameters for tube hydroforming process based on the Taguchi method  

Microsoft Academic Search

Tube hydroforming is an attractive manufacturing technology which is now widely used in many industries, especially the automobile\\u000a industry. The purpose of this study is to develop a method to analyze the effects of the forming parameters on the quality\\u000a of part formability and determine the optimal combination of the forming parameters for the process. The effects of the forming

Bing Li; T. J. Nye; Don R. Metzger

2006-01-01

223

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

224

Modeling of dynamic material behavior in hot deformation: Forging of Ti-6242  

NASA Astrophysics Data System (ADS)

A new method of modeling material behavior which accounts for the dynamic metallurgical processes occurring during hot deformation is presented. The approach in this method is to consider the workpiece as a dissipator of power in the total processing system and to evaluate the dissipated power co-content J = ?o ? ? ? d? from the constitutive equation relating the strain rate (?) to the flow stress (?). The optimum processing conditions of temperature and strain rate are those corresponding to the maximum or peak in J. It is shown that J is related to the strain-rate sensitivity ( m) of the material and reaches a maximum value (J max) when m = 1. The efficiency of the power dissipation (J/J max) through metallurgical processes is shown to be an index of the dynamic behavior of the material and is useful in obtaining a unique combination of temperature and strain rate for processing and also in delineating the regions of internal fracture. In this method of modeling, no a priori knowledge or evaluation of the atomistic mechanisms is required, and the method is effective even when more than one dissipation process occurs, which is particularly advantageous in the hot processing of commercial alloys having complex microstructures. This method has been applied to modeling of the behavior of Ti-6242 during hot forging. The behavior of ? + ? and ? preform microstructures has been exam-ined, and the results show that the optimum condition for hot forging of these preforms is obtained at 927 °C (1200 K) and a strain rate of 1CT•3 s•1. Variations in the efficiency of dissipation with temperature and strain rate are correlated with the dynamic microstructural changes occurring in the material.

Prasad, Y. V. R. K.; Gegel, H. L.; Doraivelu, S. M.; Malas, J. C.; Morgan, J. T.; Lark, K. A.; Barker, D. R.

1984-10-01

225

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

226

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

PubMed

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

Hwang, Min-Gu; Har, Dong-Hwan

2013-01-01

227

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

228

Effects of process parameters and material properties on deformation process in tube hydroforming  

Microsoft Academic Search

In this paper, factors affecting wall thickness distribution of the hydroformed tube are confirmed by FEM simulation and experimental work. The process model involves simple hydroforming of a square expanded product from a round tube using combined axial load and internal pressure. As factors, the stress ratio which is defined as nominal axial stress to nominal circumferential stress, coefficient of

Ken-ichi Manabe; Masaaki Amino

2002-01-01

229

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

SciTech Connect

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

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

2005-05-01

230

Effect of process parameters on pad damage during Au and Cu ball bonding processes  

Microsoft Academic Search

Cu wire bonding is one of the hottest trends in electronic packaging due to the cost and the electrical and thermal performance advantages of Cu wire over Au wire. However, there are many challenges to Cu wire bonding, one of which is the increased stress transmitted to the bond pad during ball bonding process. This high stress is not desirable

I. Qin; A. Shah; C. Huynh; M. Meyer; M. Mayer; Y. Zhou

2009-01-01

231

Effect of processes and processing parameters on 3-D braided preforms for composites  

Microsoft Academic Search

A general comparison about the processes, the structures and tensile properties of two 3-D braiding techniques are presented in this paper. The yarn orientation, braid width, braider curvature at fabric surface, and yarn volume fraction of both the 4-step and 2-step braids are analytically predicted in terms of the normalized cycle length which is directly related to the machine operating

W. Li; A. E. Shiekh

1988-01-01

232

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

NASA Astrophysics Data System (ADS)

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.; Ou, H.; Armstrong, C. G.

2011-05-01

233

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

234

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

235

Optimization of Injection Molding Processing Parameters for LCD Light-Guide Plates  

NASA Astrophysics Data System (ADS)

Liquid crystal display (LCD) light-guide plate injection molding has always had the unexpected deformation issue which results in variations in the quality of the resulting products. The main cause for this lies in the setting of the processing parameters. The objective of this paper is to combine grey relational analysis (GRA) with the Taguchi method to optimize multiple-quality injection molding processing parameter combination. First, a L18(21 × 37) orthogonal array was used to plan out the processing parameters that would affect the injection molding process. Then GRA was applied to resolve the drawback of single quality characteristics in the Taguchi method, and then the optimized processing parameter combination was obtained for multiple quality characteristics from the response table and the response graph from GRA. The quality characteristics of this experiment were the depth and angle of the light-guide plate V-cut microstructure. Signal-to-noise ratio (SN ratio) calculation and analysis of variance (ANOVA) would be performed to look into the results obtained from the experiment. From ANOVA the significant factors could be obtained which had the greatest effect on the light-guide plate quality characteristics, in other words, by controlling these factors, the quality characteristics of the LCD light-guide plate could be effectively controlled. Finally, the reliability and reproducibility of the experiment was verified by confirming a confidence interval (CI) of 95%.

Kuo, Chung-Feng Jeffrey; Su, Te-Li

2007-10-01

236

Optimisation of Shape Parameters and Process Manufacturing for an Automotive Safety Part  

NASA Astrophysics Data System (ADS)

In recent years, the weight and the cost of automotive vehicles have considerably increased due to the importance devoted to safety systems. It is therefore necessary to reduce the weight and the production cost of components by improving their shape and manufacturing process. This work deals with a numerical approach for optimizing the manufacturing process parameters of a safety belt anchor using a genetic algorithm (NSGA II). This type of component is typically manufactured in three stages: blanking, rounding of the edges by punching and finally, bending with a 90° angle. In this study, only the rounding and the bending will be treated. The numerical model is linked to the genetic algorithm in order to optimize the process parameters. This is implemented by using ABAQUS© script files developed in the Python programming language. The algorithm modifies the script files and restarts the FEM analysis automatically. Lemaitre's damage model is introduced in the material behaviour laws and implemented in the FEM analysis by using a FORTRAN subroutine. The influence of two process parameters (die radius and the rounding punch radius) and five shape parameters were investigated. The objective functions are (i) the material damage state at the end of the forming process, (ii) the stress field and (iii) the maximum Von Mises stress in the folded zone.

Gildemyn, Eric; Dal Santo, Philippe; Potiron, Alain; Saïdane, Delphine

2007-05-01

237

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

238

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

239

Influence of processing parameters on micro injection molded weld line mechanical properties of polypropylene (PP)  

Microsoft Academic Search

As a hot fabrication technology for micro scale parts, micro injection molding is receiving increasing market attention. Improving\\u000a mechanical properties of micro parts should be an important issue in the micro injection molding process. The relation between\\u000a weld line strength in micro injection molding parts and processing parameters is investigated. A visual mold with variotherm\\u000a unit is designed and constructed,

Lei Xie; Gerhard Ziegmann

2009-01-01

240

Sesame cake protein hydrolysis by alcalase: Effects of process parameters on hydrolysis, solubilisation, and enzyme inactivation  

Microsoft Academic Search

We investigated the effects of process parameters (substrate concentration, enzyme concentration, temperature and pH) on the\\u000a hydrolysis and solubilization of sesame cake protein as well as enzyme stability. The sesame cake protein was hydrolyzed by\\u000a Alcalase enzyme (a bacterial protease produced by a selected strain of Bacillus Licheniformis) that was chosen among five commercial enzymes examined. The optimum process conditions

Elçin Demirhan; Dilek K?l?ç Apar; Belma Özbek

2011-01-01

241

Optimization of the processing parameters in melt blending of thermoplastic polyurethane and poly dimethyl siloxane rubber  

Microsoft Academic Search

This article emphasizes the optimization of processing parameters required for the blending of polyether-based thermoplastic polyurethane (TPU) and poly dimethyl siloxane (PDMS) rubber. Taguchi methodology was adapted as a statistical tool in the design of experiment to optimize processing conditions on the basis of tensile strength and impact strength for 50:50 blend of TPU and PDMS. L9 (33) orthogonal array

Jineesh Ayippadath Gopi; Golok Bihari Nando

2012-01-01

242

Effects of Melt Pool Variables and Process Parameters in Laser Direct Metal Deposition of Aerospace Alloys  

Microsoft Academic Search

Despite considerable advances in of laser direct metal deposition (LDMD) process optimization, there is rather limited work reported on the effects of melt pool variables on the final deposit characteristics. This article considers the effects of process parameters and melt pool characteristics on the deposition of Inconel 718 powder on a Ti-6Al-4 V thin wall. A 1.5 kW diode laser and LDMD

Kamran Shah; Andrew J. Pinkerton; Ahmad Salman; Lin Li

2010-01-01

243

Optimisation of SU8 processing parameters for deep X-ray lithography  

Microsoft Academic Search

The negative photoresist SU-8 has been recognised as an unique resist, equally useful for conventional UV lithography as well as deep X-ray lithography (DXRL) applications [2, 7, 12, 17, 18]. One of the major limitations in the use of SU-8 in lithographic processes is the occurrence of internal stress [15]. The processing parameters investigated for DXRL of SU-8 included resist

R. L. Barber; M. K. Ghantasala; R. Divan; K. D. Vora; E. C. Harvey; D. C. Mancini

2005-01-01

244

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

NASA Technical Reports Server (NTRS)

An adaptive-performance-seeking control system which optimizes the quasi-steady-state performance of the F-15 propulsion system is discussed. 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 Kalman 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

245

Optimization of laser processing techniques and parameters for laser transformation hardening with multi-objectives  

NASA Astrophysics Data System (ADS)

The new idea of the optimum controlling of laser processing technique and parameters with multi-objectives and multi-variables was put forth. With the comprehensive discussion about the quality index of laser transformation hardening (LTH), a hierarchical structure of the LTH quality index system and a decision-making framework model of the quality control were set up. Then, based on the conclusions of the sensitivities of LTH parameters' influences on the case indexes, the principle of LTH's parameters optimization was discussed by means of fuzzy decision method. With the combination of the principle and the sectionlly changing scanning velocity technique, which can effectively the uniformity of longitudinal case-distribution, a decision-making framework for optimal controlling on the laser scanning technique and the parameters with multi-objectives were put forward. An optimization model was developed and the validity of the model was verified both by theoretical computation and experimental results.

Wu, Gang; Hong, Lei

2008-03-01

246

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

NASA Astrophysics Data System (ADS)

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

Li, Xuefeng; Cao, Guangzhan; Liu, Hongjun

2014-04-01

247

Simple and Efficient Estimation of Parameters of Non-Gaussian Autoregressive Processes.  

National Technical Information Service (NTIS)

A new technique for the estimation of autoregressive filter parameters of a non-Gaussian autoregressive process is proposed. The probability density function of the driving noise is assumed to be known. The new technique is a two-stage procedure motivated...

S. M. Kay D. Sengupta

1986-01-01

248

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

PubMed

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

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

2009-01-01

249

A DISTRIBUTED PARAMETER APPROACH TO THE DYNAMICS OF ROTARY DRYING PROCESSES  

Microsoft Academic Search

A nonequilibrium distributed parameter model for rotary drying and cooling processes described by a set of partial differitial equations with nonlinear algebraic constraints is developed in this work. These equations arise from the multi–phase heat and mass balances on a typical rotary dryer. A computational algorithm is devekped by employing a polynonial approximation ( orthogonal collocation) with a glotal splinc

E. Y. Wang; I. T. Cameron; I. D. Lister; P. L. Dougla

1993-01-01

250

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

Microsoft Academic Search

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

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

2011-01-01

251

Prediction of forming limits and parameters in the tube hydroforming process  

Microsoft Academic Search

Determination of process limits and parameters for hydroforming was conducted applying widely known plasticity, membrane and thin-thick walled tube theories. Analytical predictions were compared with experimental findings. Simple but useful analytical models to predict buckling, wrinkling and bursting as well as axial force, internal pressure, counter force and thinning in tube hydroforming were verified with experimental results.

Muammer Koç; Taylan Altan

2002-01-01

252

Prediction of forming limits and parameters in the tube hydroforming process  

Microsoft Academic Search

Determination of process limits and parameters for hydroforming was conducted applying widely known plasticity, membrane and thin-thick walled tube theories. Analytical predictions were compared with experimental findings. Simple but useful analytical models to predict buckling, wrinkling and bursting as well as axial force, internal pressure, counter force and thinning in tube hydroforming were verified with experimental results. ? 2001 Elsevier

Muammer Koca; Taylan Altan

2002-01-01

253

Process and control loop performance monitoring through detection of abrupt parameter changes  

Microsoft Academic Search

The paper is concerned with process and controller loop performance monitoring through model validation and detection of abrupt changes of model parameters. The local approach for detection of abrupt changes is adopted in the paper as a computational framework for the change detection. This approach has the ability to detect small changes quite effectively. To enhance its robustness in the

B. Huang

1999-01-01

254

Process parameters optimization for friction stir welding of RDE40 aluminium alloy using Taguchi technique  

Microsoft Academic Search

Taguchi approach was applied to determine the most influential control factors which will yield better tensile strength of the joints of friction stir welded RDE-40 aluminium alloy. In order to evaluate the effect of process parameters such as tool rotational speed, traverse speed and axial force on tensile strength of friction stir welded RDE-40 aluminium alloy, Taguchi parametric design and

A. K. LAKSHMINARAYANAN; V. BALASUBRAMANIAN

2008-01-01

255

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

256

Optimisation of process parameters for bioreduction of azo dyes using Bacillus firmus under batch anaerobic condition  

Microsoft Academic Search

A new dye decolourising bacterial strain was isolated from textile wastewater and identified as Bacillus firmus. The study indicated that the bacterium could efficiently decolourise different azo dyes under static culture conditions. Characterisation of the efficiency of azo dye reduction by this isolate using both spectral and HPLC analysis was found to be a function of process parameters which include

C. J. Ogugbue; T. Sawidis

2011-01-01

257

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

NASA Astrophysics Data System (ADS)

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

Indratno, S. W.; Shabrina, A.

2014-02-01

258

Experiment study of temperature parameter effect on bonding process and quality in thermosonic wire bonding  

Microsoft Academic Search

An experiment study of temperature parameter on bonding process and bonding quality in thermosonic wire bonding was performed in this paper. The experiment method was based on changing regularly bonding temperature and gaining the bonding strength by shearing gold ball joint by a high precision gauge. The experiment results and analysis can find out the relationship of bonding temperature and

Long Zhili; Han Lei; Wu Yunxin; Zhong Jue

2005-01-01

259

OPTIMIZATION OF PROCESS PLANNING PARAMETERS FOR ROTATIONAL COMPONENTS BY GENETIC ALGORITHMS  

Microsoft Academic Search

In CAPP systems process parameter optimization is one of the key areas for research and development. Traditional techniques have very limited scope because of the complexity of the optimization problem. Due to the rapid development of computer technology Genetic Algorithms (GAs), which are robust search algorithm, have been found to be suitable and efficient tools for optimization in such cases.

Nafis Ahmad; Anwarul Haque

2001-01-01

260

Optimization of the process parameters for the removal of phosphate from drinking water by electrocoagulation  

Microsoft Academic Search

The present studies provide the purification of drinking water containing phosphate by electrocoagulation process using zinc as the anode and stainless steel as the cathode. The experimental parameters like electrolyte pH, temperature and current density, and so forth, on the removal efficiency of phosphate were carried out. The adsorption capacity was evaluated using both Langmuir and Freundlich isotherm models. The

Subramanyan Vasudevan; Jothinathan Lakshmi; Ganapathy Sozhan

2009-01-01

261

The computer-aided hot-forging simulation of P/M connecting rods  

NASA Astrophysics Data System (ADS)

Computer-aided engineering simulation techniques using a computational method are increasingly being applied to the simulation of powder metallurgy (P/M) component processing. This emerging area of applied research in the P/M industry offers the promise of a cheaper and more reliable route to part design, analysis, and development. In order to meet this goal, simulation tools that take into account the physics and mechanics of the deformation process have to be developed. This article reports one such simulation procedure as applied to the hot forging of a P/M connecting rod on a three-dimensional model. This review focuses briefly on the development of a new model, which in the study is basedon the finite-element method. Thestudy brings out a perspective for understanding the mechanical behavior of the porous material within the scope of a P/M industrial component such as a connecting rod.

Jinka, Ashoka G. K.

1995-08-01

262

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

263

Seminar on Copper and Copper Alloy Forged and Pressed Components: Proceedings of the Seminar Held in Pune, December 1-2, 1977.  

National Technical Information Service (NTIS)

Various papers presented at the seminar covered the following topics: Application of Forged and Pressed Copper and Copper Alloy Components; Copper Base Alloy Forgings for High Pressure Applications; Materials for Forged and Pressed Components; Copper and ...

1977-01-01

264

Application of image-processing software to characterize the photomask key parameters for future technologies  

NASA Astrophysics Data System (ADS)

The intent of photomask metrology has always been to understand the relationship between the features on the photomask and the design data. This desire has been actuated by the necessity to close the loop between the photomask process steps and the wafer lithography. As the Si technology approaches 0.25 micron and beyond, and the employment of resolution enhancement techniques (OPC and phase shifting mask) to extend the capability of optical lithography, both the photomask critical dimension control and pattern fidelity become important and challenging. Describing the features accurately on the photomask is critical to ensure the quality of photomasks. In this paper, the image processing software is examined for measuring and characterizing key photomask parameters, such as edge roughness, edge defects, isolated defects, corner rounding, and contacts. With this image processing software, the effect of mask processing on those key mask parameters, and the impact of those key parameters on defect printability were characterized. Thus, the application of image processing software will contribute immensely to photomask metrology.

Tran, An; Schmidt, Michael R.; Farnsworth, Jeff N.; Yan, Pei-Yang

1997-08-01

265

Computerized Optimization of the Process Parameters in Laser-Assisted Milling  

NASA Astrophysics Data System (ADS)

Machining advanced materials, e.g. titanium alloys, usually results in a short tool life. Laser-assisted milling represents an innovative method to enhance machinability with less tool wear and an increased material removal rate. The material is heated locally and thereby softened before machining. This paper describes a thermo-mechanical simulation of a laser-assisted milling process in order to achieve a controlled heat impact. For that purpose the influence of different material parameters on the temperature field was analyzed computationally. The penetration depth of the laser induced heat and the thermally induced internal loads were investigated considering the loss of material and thus of heat during the milling process. Finally, the laser and the milling parameters were adapted for a real laser-assisted process.

Wiedenmann, R.; Langhorst, M.; Zaeh, M. F.

266

Parameter estimation of integrating and time delay processes using single relay feedback test.  

PubMed

Autotuning using relay feedback is widely used to identify low order integrating plus dead time (IPDT) systems as the method is simple and is operated in closed-loop without interrupting the production process. Oscillatory responses from the process due to ideal relay input are collected to calculate ultimate properties of the system that in turn are used to model the responses as functions of system model parameters. These theoretical models of relay response are validated. After adjusting the phase shift, input and output responses are used to find land mark points that are used to formulate algorithms for parameter estimation of the process model. The method is even applicable to distorted relay responses due to load disturbance or measurement noise. Closed-loop simulations are carried out using model based control strategy and performances are calculated. PMID:21777915

Panda, Rames C; Vijayan, V; Sujatha, V; Deepa, P; Manamali, D; Mandal, A B

2011-10-01

267

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

PubMed

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

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

2014-09-15

268

Effect of particle size, forging and ageing on the mechanical fatigue characteristics of Al6082\\/SiC p metal matrix composites  

Microsoft Academic Search

Addition of inexpensive silicon carbide particulates (SiCp) in the aluminium alloy matrix results in materials with properties non-obtainable in monolithic materials. The forging process\\u000a results in improved properties as well as forms a shape of the final product. The age-hardening processes accelerate the coarse\\u000a hardening process of the composites and improve strength and ductility. The size, morphology and volume fraction

Raja Thimmarayan; G. Thanigaiyarasu

2010-01-01

269

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

PubMed Central

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

Deshmukh, Ketkee; Amin, Purnima

2013-01-01

270

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

271

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

272

Parameter identification of process simulation models as a means for knowledge acquisition and technology transfer  

NASA Astrophysics Data System (ADS)

Process simulation models are usually empirical, therefore there is an inherent difficulty in serving as carriers for knowledge acquisition and technology transfer, since their parameters have no physical meaning to facilitate verification of the dependence on the production conditions; in such a case, a 'black box' regression model or a neural network might be used to simply connect input-output characteristics. In several cases, scientific/mechanismic models may be proved valid, in which case parameter identification is required to find out the independent/explanatory variables and parameters, which each parameter depends on. This is a difficult task, since the phenomenological level at which each parameter is defined is different. In this paper, we have developed a methodological framework under the form of an algorithmic procedure to solve this problem. The main parts of this procedure are: (i) stratification of relevant knowledge in discrete layers immediately adjacent to the layer that the initial model under investigation belongs to, (ii) design of the ontology corresponding to these layers, (iii) elimination of the less relevant parts of the ontology by thinning, (iv) retrieval of the stronger interrelations between the remaining nodes within the revised ontological network, and (v) parameter identification taking into account the most influential interrelations revealed in (iv). The functionality of this methodology is demonstrated by quoting two representative case examples on wastewater treatment.

Batzias, Dimitris F.; Ifanti, Konstantina

2012-12-01

273

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

274

Optimization of the Solution and Processing Parameters for Strontium Titanate Thin Films for Electronic Devices  

NASA Astrophysics Data System (ADS)

Metallo-organic solution deposition (MOSD) and spin-coating were used to deposit strontium titanate (SrTiO3 or STO) thin films on Si and metalized Si substrates. In addition, a thermodynamic model was constructed based on the Landau polynomial for the free energy. Using this model, the thin film strain due to the difference in thermal expansion coefficients (TECs) of the film and substrate was calculated, as well as its effect on the permittivity and tunability. It was found that a large tensile thermal strain develops in the STO/Si material system, and this strain significantly lowers the dielectric response as compared to bulk STO. A multi-dimensional parameter optimization process was used to systematically vary the solution, deposition, and processing parameters of the STO thin films. These parameters include the precursor solution heating, solution molarity/concentration, solution aging, spin-coating recipe, pyrolysis procedure/temperature, annealing temperature, and annealing oxygen environment. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (SE), and dielectric/insulating measurements were used to characterize the STO thin film devices. By optimizing various deposition parameters, such as the solution molarity and the pyrolysis temperature, the tensile stress induced from the difference in TECs of the film and substrate, which was predicted by the thermodynamic theory, can be reduced or completely eliminated. This stress relaxation is achieved through the tailoring of compressive "growth stresses" by optimizing the precursor solution molarity as well as the post-deposition heat treatment processing. By utilizing the multi-dimensional parameter optimization process, high-quality, electronic-grade thin film STO can be deposited via the affordable, simple, and industry-standard MOSD technique.

Weiss, Claire Victoria

275

Role of process parameters in the texture evolution of TiN films deposited by hollow cathode discharge ion plating  

Microsoft Academic Search

TiN coatings deposited by various physical vapor deposition (PVD) processes often exhibit certain preferred orientations, which are heavily affected by process parameters. This investigation thoroughly examines the preferred orientation of TiN film deposited by a hollow cathode discharge (HCD) ion plating system. The roles of process parameters in determining the preferred orientation of TiN films were studied. Process parameters such

Y. M Chen; G. P Yu; J. H Huang

2001-01-01

276

17Oexcess in meteoric water: as a new isotopic parameter to decipher water cycle processes  

NASA Astrophysics Data System (ADS)

Classical water stable isotopes (dD and d18O) have been used for more than 50 years with the aim to understand the links between water cycle and climate. They provide information on either temperature or precipitation changes depending on the latitudes. Their combination, in the so-called d-excess, brings some information on climatic conditions occurring during non equilibrium processes along air masses histories (evaporation over the Oceans, reevaporation of droplets in convective systems, continental recycling or ice crystals formation). Recently, the possibility to measure with high precision d17O in water has enabled to introduce a new parameter, 17Oexcess, resulting from the combination of d18O and d17O. According to both observations and modeling works, this new isotopic parameter is able to decipher some of the non equilibrium processes: when measured in ice core, it is expected to be a more direct tracer of relative humidity of the oceanic evaporative regions than d-excess. In order to better understand what controls this new parameter as well as to extract the maximum climatic information from the combination of 17Oexcess and d-excess, we present different original studies combining these two parameters in several key regions. First, data collected in Niger, West Africa, at scales ranging from the convective system to the seasonal cycle confirm the strong influence of relative humidity on 17Oexcess through the rain reevaporation process. Second, seasonal cycles in the Zongo Valley (Tropical Bolivia) suggest that rain recycling along air masses trajectories have different signatures on d-excess and 17Oexcess leading to decipher the different processes. Third, we study how local processes (precipitation, sublimation) in polar region (Greenland) can affect 17Oexcess archived in ice core with respect to d-excess records through (1) isotopic measurements of vapor versus precipitation collected at the NEEM station and (2) seasonal cycles measured from snow pits.

Landais, A.; Guillevic, M.; Steen-Larsen, H.; Vimeux, F.; Bouygues, A.; Falourd, S.; Risi, C. M.; Bony, S.

2009-12-01

277

High-Strength and Toughness Forging Steels for Automobile Underbody Parts to be Produced without Subsequent Heat Treatment.  

National Technical Information Service (NTIS)

High strength and toughness forging steels that can be used in the as-forged state are finding wide application in the production of mechanical parts of automobiles, industrial machinery, etc. without subsequent heat treatment (quenching and tempering). T...

Y. Koyasu H. Takada T. Takahashi H. Takeda N. Ishii

1990-01-01

278

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

Federal Register 2010, 2011, 2012, 2013

...A-570-803] Heavy Forged Hand Tools, Finished or Unfinished, With...Timken), as clarified by Diamond Sawblades Mfrs. Coalition v...1374 (Fed. Cir. 2010) (Diamond Sawblades), the Department...review on heavy forged hand tools, finished or unfinished,...

2012-07-06

279

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

NASA Astrophysics Data System (ADS)

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

Boutin, Olivier

2012-03-01

280

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

281

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

282

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

283

The structure and properties of forged composite high-speed steel: Titanium carbide  

Microsoft Academic Search

The structure of a powder composite (carbide steel) based on high-speed steel with dispersed inclusions of titanium carbide\\u000a and obtained by forging powdered billets is investigated. The elemental and chemical composition of the material is determined.\\u000a The physicomechanical properties of the forged carbide steels obtained are compared with those obtained by other methods.

L. I. Svistun; D. V. Dmitrenko; R. L. Plomod’yalo; G. G. Serdyuk

2009-01-01

284

Current steel forgings and their properties for steam generator of nuclear power plant  

Microsoft Academic Search

Current steel forgings used for the construction of steam generators (SGs) for a nuclear power plant (NPP) were introduced from the following three (3) features. (1) Integral type steel forgings such as (i) primary head integrated with nozzles, manways and supports, (ii) steam drum head integrated with nozzle and handhole, (iii) conical shell integrated with cylindrical sections and handholes, have

Komei Suzuki; Ikuo Sato; Mikio Kusuhashi; Hisashi Tsukada

2000-01-01

285

Effect of Alloying Elements on Thermal Wear of Cast Hot-Forging Die Steels  

Microsoft Academic Search

The effect of main alloying elements on thermal wear of cast hot-forging die steels was studied. The wear mechanism was discussed. The results show that alloying elements have significant influences on the thermal wear of cast hot-forging die steels. The wear rates decrease with an increase in chromium content from 3% to 4% and molybdenum content from 2% to 3%,

Shu-qi WANG; Kang-min CHEN; Xiang-hong CUI; Qi-chuan JIANG; Bian HONG

2006-01-01

286

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

NASA Astrophysics Data System (ADS)

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

Kahlen, Franz-Josef

2000-08-01

287

Optimization of Atmospheric Plasma Spray Process Parameters using a Design of Experiment for Alloy 625 coatings  

NASA Astrophysics Data System (ADS)

Alloy 625 is a Ni-based superalloy which is often a good solution to surface engineering problems involving high temperature corrosion, wear, and thermal degradation. Coatings of alloy 625 can be efficiently deposited by thermal spray methods such as Air Plasma Spraying. As in all thermal spray processes, the final properties of the coatings are determined by the spraying parameters. In the present study, a D-optimal experimental design was used to characterize the effects of the APS process parameters on in-flight particle temperature and velocity, and on the oxide content and porosity in the coatings. These results were used to create an empirical model to predict the optimum deposition conditions. A second set of coatings was then deposited to test the model predictions. The optimum spraying conditions produced a coating with less than 4% oxide and less than 2.5% porosity. The process parameters which exhibited the most important effects directly on the oxide content in the coating were particle size, spray distance, and Ar flow rate. The parameters with the largest effects directly on porosity were spray distance, particle size, and current. The particle size, current, and Ar flow rate have an influence on particle velocity and temperature but spray distance did not have a significant effect on either of those characteristics. Thus, knowledge of the in-flight particle characteristics alone was not sufficient to control the final microstructure. The oxidation index and the melting index incorporate all the parameters that were found to be significant in the statistical analyses and correlate well with the measured oxide content and porosity in the coatings.

Azarmi, F.; Coyle, T. W.; Mostaghimi, J.

2008-03-01

288

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

289

Applying an interferometric exposure model to analyze the influences of process parameters on the linewidth  

NASA Astrophysics Data System (ADS)

We utilize a modified interferometric exposure model, enhanced with the Beer-Lambert law, to study how some process parameters influence the structural dimensions within the whole exposure area. An experimental apparatus is built to verify the accuracy of this model. The simulation results indicate that when the incident angle is larger than 15°, the effect of the beam deformation cannot be neglected. One cannot readily obtain periodic structures with the same dimensions during static exposure because of the Gaussian distribution of the light intensity. The theoretical results match the experimental ones quite well. The variation of Dill's parameter A has a greater influence on the transmittance and the linewidth when A is decreasing. If a poor contrast fringe is exposed in the photoresist, it will not only cause a greater nonuniformity of the structural dimensions but also a decreased aspect ratio in the structure after the development process.

Chien, Cheng-Wei; Chen, Jyh-Chen; Lee, Ju-Yi

2006-11-01

290

Critical operational parameters for zero sludge production in biological wastewater treatment processes combined with sludge disintegration.  

PubMed

Mathematical models were developed to elucidate the relationships among process control parameters and the effect of these parameters on the performance of anoxic/oxic biological wastewater processes combined with sludge disintegrators (A/O-SD). The model equations were also applied for analyses of activated sludge processes hybrid with sludge disintegrators (AS-SD). Solubilization ratio of sludge in the sludge disintegrator, alpha, hardly affected sludge reduction efficiencies if the biomass was completely destructed to smaller particulates. On the other hand, conversion efficiency of non-biodegradable particulates to biodegradable particulates, beta, significantly affected sludge reduction efficiencies because beta was directly related to the accumulation of non-biodegradable particulates in bioreactors. When 30% of sludge in the oxic tank was disintegrated everyday and beta was 0.5, sludge reduction was expected to be 78% and 69% for the A/O-SD and AS-SD processes, respectively. Under this condition, the sludge disintegration number (SDN), which is the amount of sludge disintegrated divided by the reduced sludge, was calculated to be around 4. Due to the sludge disintegration, live biomass concentration decreased while other non-biodegradable particulates concentration increased. As a consequence, the real F/M ratio was expected to be much higher than the apparent F/M. The effluent COD was maintained almost constant for the range of sludge disintegration rate considered in this study. Nitrogen removal efficiencies of the A/O-SD process was hardly affected by the sludge disintegration until daily sludge disintegration reaches 40% of sludge in the oxic tank. Above this level of sludge disintegration, autotrophic biomass concentration decreases overly and TKN in the effluent increases abruptly in both the A/O-SD and AS-SD processes. Overall, the trends of sludge reduction and effluent quality according to operation parameters matched well with experimental results found in literatures. PMID:16061269

Yoon, Seong-Hoon; Lee, Sangho

2005-09-01

291

Predicting Simulation Parameters of Biological Systems Using a Gaussian Process Model.  

PubMed

Finding optimal parameters for simulating biological systems is usually a very difficult and expensive task in systems biology. Brute force searching is infeasible in practice because of the huge (often infinite) search space. In this article, we propose predicting the parameters efficiently by learning the relationship between system outputs and parameters using regression. However, the conventional parametric regression models suffer from two issues, thus are not applicable to this problem. First, restricting the regression function as a certain fixed type (e.g. linear, polynomial, etc.) introduces too strong assumptions that reduce the model flexibility. Second, conventional regression models fail to take into account the fact that a fixed parameter value may correspond to multiple different outputs due to the stochastic nature of most biological simulations, and the existence of a potentially large number of other factors that affect the simulation outputs. We propose a novel approach based on a Gaussian process model that addresses the two issues jointly. We apply our approach to a tumor vessel growth model and the feedback Wright-Fisher model. The experimental results show that our method can predict the parameter values of both of the two models with high accuracy. PMID:23482410

Zhu, Xiangxin; Welling, Max; Jin, Fang; Lowengrub, John

2012-12-01

292

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

293

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

294

Optimization of Atmospheric Plasma Spray Process Parameters using a Design of Experiment for Alloy 625 coatings  

Microsoft Academic Search

Alloy 625 is a Ni-based superalloy which is often a good solution to surface engineering problems involving high temperature\\u000a corrosion, wear, and thermal degradation. Coatings of alloy 625 can be efficiently deposited by thermal spray methods such\\u000a as Air Plasma Spraying. As in all thermal spray processes, the final properties of the coatings are determined by the spraying\\u000a parameters. In

F. Azarmi; T. W. Coyle; J. Mostaghimi

2008-01-01

295

Formulation of a practical algorithm for parameter estimation with process and measurement noise  

NASA Technical Reports Server (NTRS)

A new formulation is proposed for the problem of parameter estimation in dynamic systems with both process and measurement noise. The formulation applies to continuous-time state space system models with discrete-time measurements. Previous formulations of this problem encountered several theoretical and practical difficulties which are overcome by the new formulation. The most important element of the new formulation is a reparameterization of the unknown noise covariances. A computer program that implements the new formulation is available.

Maine, R. E.; Iliff, K. W.

1983-01-01

296

Effect of process parameters on the synthesis of YAG nano-crystallites in supercritical solvent  

Microsoft Academic Search

Nano-scaled aluminum yttrium garnet (YAG) powders with a spherical morphology were prepared by a mixed-solvo-thermal method under moderate reaction conditions using inexpensive starting materials. The effects of the changing process parameters on phase evolution, constitute and morphology of the resulting samples were characterized by X-ray diffraction (XRD), DTA–TG, transmission electronic microscope (TEM) and HRTEM techniques. The results show that pure

Xia Li; Qiang Li; Jiyang Wang; Shunliang Yang

2006-01-01

297

Effects of processing parameters on the temperature field of selective laser melting metal powder  

Microsoft Academic Search

Based on temperature-dependent thermophysical parameters and nonlinear phase transformation from powder to liquid, a three-dimensional\\u000a transient thermal finite model of selective laser melting process is developed. Commercial ANSYS software is used to simulate\\u000a the distribution of the temperature field in selective laser melting. The simulation results show that a lower scan speed,\\u000a higher laser power, and a lower scan interval

Ruidi Li; Yusheng Shi; Jinhui Liu; Huashan Yao; Wenxian Zhang

2009-01-01

298

Effect of processing parameters on the microstructure and mechanical behavior of silica-calcium phosphate nanocomposite  

Microsoft Academic Search

Silica-calcium phosphate nanocomposite (SCPC) is a bioactive ceramic characterized by superior bone regenerative capacity\\u000a and resorbability when compared to traditional bioactive ceramics. The aim of the present study is to evaluate the effect\\u000a of processing parameters on the microstructure and mechanical properties of SCPC. Cylinders were prepared by pressing the\\u000a ceramic powder at 200, 300 or 400 MPa and sintering at

Xueran Liu; Ahmed EI-Ghannam

2010-01-01

299

Optimization of Injection Molding Processing Parameters for LCD Light-Guide Plates  

Microsoft Academic Search

Liquid crystal display (LCD) light-guide plate injection molding has always had the unexpected deformation issue which results\\u000a in variations in the quality of the resulting products. The main cause for this lies in the setting of the processing parameters.\\u000a The objective of this paper is to combine grey relational analysis (GRA) with the Taguchi method to optimize multiple-quality\\u000a injection molding

Chung-Feng Jeffrey Kuo; Te-Li Su

2007-01-01

300

The effect of process parameters on kinetics and mechanisms of Co removal by bone char  

Microsoft Academic Search

Bone char powder, composed mainly of poorly crystalline hydroxyapatite (Ca10(PO4)6(OH)2), carbon and CaCO3, has potential applicability in the removal of Co ions from contaminated effluents. In the present study, the influence of process parameters: particle size, agitation speed, initial pH and initial sorbate concentration, onto kinetics and mechanism of Cosorption was studied and discussed. In order to describe and compare

Slavko D. Dimovi?; Ivana D. Smi?iklas; Marija Z. Šljivi?-Ivanovi?; Ilija B. Ple?aš; Latinka Slavkovi?-Beškoski

2011-01-01

301

The effects of process parameters on spatter deposition in laser percussion drilling  

Microsoft Academic Search

This paper reports on the characterisation and analysis of spatter deposition during laser drilling in Nimonic 263 alloy for various laser processing parameters using a fibre-optic delivered 400 W Nd:YAG laser. The principal findings are a large proportion of the spatter (approx. > 70%) was deposited due to the initial laser pulses (before beam breakthrough) required to drill a through-hole.

D. K. Y. Low; L. Li; P. J. Byrd

2000-01-01

302

Parameter optimization in a methane detection system using a broadband source and interferometric signal processing  

Microsoft Academic Search

A D-fiber evanescent field methane sensor has been reported by Culshaw et al., where a sinusoidally modulated Fabry-Perot interferometer was used for signal processing. To optimize the sensitivity, it is essential to establish a relation between output signal, methane concentration, and certain other key parameters. Previous work with open-path cells, which use a sawtooth driven Fabry-Perot interferometer, shows a noise-limited

Wei Jin; George Stewart; Brian Culshaw; Stuart C. Murray; David Pinchbeck

1994-01-01

303

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

PubMed Central

The purpose of this work was to optimize the process parameters required for the production of spray-dried oily core nanocapsules (NCs) with targeted size and drug yield using a two-level four-factor fractional factorial experimental design (FFED). The coded process parameters chosen were inlet temperature (X1), feed flow rate (X2), atomizing air flow (X3), and aspiration rate (X4). The produced NCs were characterized for size, yield, morphology, and powder flowability by dynamic light scattering, electron microscope, Carr’s index, and Hausner ratio measurement, respectively. The mean size of produced NCs ranged from 129.5 to 444.8 nm, with yield varying from 14.1% to 31.1%. The statistical analysis indicated an adequate model fit in predicting the effect of process parameters affecting yield. Predicted condition for maximum yield was: inlet temperature 140°C, atomizing air flow 600 L/h, feed flow rate 0.18 L/h, and aspiration air flow set at 100%, which led to a yield of 30.8%. The morphological analysis showed the existence of oily core and spherical nanostructure. The results from powder flowability analysis indicated average Carr’s index and Hausner ratio of 42.77% and 1.76, respectively. Spray-dried oily core NCs with size lower than 200 nm were successfully produced, and the FFED proved to be an effective approach in predicting the production of spray-dried NCs of targeted yield.

Zhang, Tao

2010-01-01

304

Setting priorities in health care organizations: criteria, processes, and parameters of success  

PubMed Central

Background Hospitals and regional health authorities must set priorities in the face of resource constraints. Decision-makers seek practical ways to set priorities fairly in strategic planning, but find limited guidance from the literature. Very little has been reported from the perspective of Board members and senior managers about what criteria, processes and parameters of success they would use to set priorities fairly. Discussion We facilitated workshops for board members and senior leadership at three health care organizations to assist them in developing a strategy for fair priority setting. Workshop participants identified 8 priority setting criteria, 10 key priority setting process elements, and 6 parameters of success that they would use to set priorities in their organizations. Decision-makers in other organizations can draw lessons from these findings to enhance the fairness of their priority setting decision-making. Summary Lessons learned in three workshops fill an important gap in the literature about what criteria, processes, and parameters of success Board members and senior managers would use to set priorities fairly.

Gibson, Jennifer L; Martin, Douglas K; Singer, Peter A

2004-01-01

305

Multiobjective Optimization of Friction Stir Welding Process Parameters on Aluminum Alloy AA 5083 Using Taguchi-Based Grey Relation Analysis  

Microsoft Academic Search

This article presents the optimization of process parameters in friction stir welding (FSW) of Aluminum Alloy AA 5083 with multiple responses based on orthogonal array with grey relational analysis. The L9 orthogonal array of Taguchi experimental design is used for optimizing the FSW process parameters on tensile strength of FSW welds and total input power required for the process. The

Sundaravel Vijayan; R. Raju; S. R. K Rao

2010-01-01

306

Focusing aberration corrections for ultrasonic inspections of disk forgings when using a surface compensating mirror and segmented annular phased array  

Microsoft Academic Search

Phased array transducers are playing an increasing role in ultrasonic nondestructive evaluation inspection applications, and one area of their use is in the inspection of critical jet engine components such as titanium alloy turbine disk forgings. Inspection of these forging disks is performed during stages of their manufacturing, particularly at an intermediate stage when the forging disk has a deliberate

Jon Hiram Friedl Jr.

2010-01-01

307

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

308

A Digital Image Processing Based Methodology for the Extraction of the Quantitative Parameters of a Superficial Drainage Basin  

Microsoft Academic Search

This work presents the necessary steps to obtain the quantitative parameters of a superficial drainage basin, using digital image processing techniques such as segmentation and mathematical morphology.

Camillo Jorge Santos Oliveira

2001-01-01

309

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

310

Laser parameters for silicon solar cell processing: a simulation of heat transfer and material modification  

NASA Astrophysics Data System (ADS)

In this paper we present a simple technique for approximating laser process parameters needed for laser processing of crystalline silicon solar cells. The calculation computes the changes of silicon material properties during the time of laser-material interaction. As the laser pulse energy modifies optical and thermal properties of silicon, the chronological segmentation illustrates the temperature rise within the irradiated volume and indicates the time needed for melting or evaporation. Depending on the desired material modification, commercially available laser sources are analyzed regarding their process suitability. Simulating the laser system performance reveals its theoretical output and determines its expected efficiency. Simulations in this paper correlate well to experimental data and are done for different fields of interest: a) ablation rate during laser drilling for EWT cells, using IR wavelengths in the order of 1 ?s b) depth and width of laser grooves as used for Laser Grooved Buried Contact cells (LGBC) or edge isolation, using wavelengths in the IR and VIS c) process windows during selective laser doping with 532 nm using PSG as sole phosphorous source d) laser parameters needed for Laser-Fired Contacts (LFC).

Baier, T.; Glaeser, G.; Wanka, H.

2012-10-01

311

Effect of processing parameters on the electrochemical properties of a polymer electrolyte prepared by the phase inversion process  

NASA Astrophysics Data System (ADS)

Porous polymer membranes based on poly(vinylidene fluoride-co-hexafluoropropylene) were prepared by the phase inversion process, and the effect of processing parameters, such as the type of solvent and concentration of the polymer solution, on the membrane morphology and electrochemical properties of a polymer electrolyte (PE) was investigated. The membranes prepared were characterized by scanning electron microscopy and differential scanning calorimetry. PEs were prepared by soaking the porous membrane in 1 M LiPF6 in ethylene carbonate/dimethyl carbonate, and their electrochemical performance was studied. The polymer concentration and/or non-solvent greatly influenced the morphology and electrochemical performance of the PE. A conductivity of ~10-3 S cm-1 and charge/discharge capacities of ~140 mAh g-1 for the Li/LiFePO4 cell were obtained.

Zhao, Xiaohui; Kim, Dul-Sun; Raghavan, Prasanth; Ahn, Jou-Hyeon; Ahn, Hyo-Jun; Ryu, Ho-Suk; Cho, Gyu-Bong; Noh, Jung-Pil

2010-05-01

312

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

313

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

PubMed

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

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

2013-01-01

314

A Self-Adaptive Parameter Optimization Algorithm in a Real-Time Parallel Image Processing System  

PubMed Central

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

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

2013-01-01

315

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

316

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

NASA Technical Reports Server (NTRS)

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

Sankaran, K. K.

1987-01-01

317

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

318

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

319

Statistical optimization of process parameters for landfill leachate treatment using electro-Fenton technique.  

PubMed

Mature landfill leachate is typically non-biodegradable and contains high concentration of refractory organics. The aim of this research was to optimize operating parameters in electro-Fenton process, for the removal of recalcitrant organics from semi-aerobic landfill leachate using response surface methodology (RSM). Effectiveness of important process parameters H(2)O(2)/Fe(2+) molar ratio, current density, pH and reaction time were determined, optimized and modeled successfully. Significant quadratic polynomial models were obtained (R(2)=0.9972 and 0.9984 for COD and color removals, respectively). Numerical optimization based on desirability function were employed; in a 43 min trial 94.07% of COD and 95.83% of color were removed at pH 3 and H(2)O(2)/Fe(2+) molar ratio 1, while current density was 49 mA/cm(2). The results indicate that E-Fenton process was an effective technology for semi-aerobic landfill leachate treatment. PMID:20022166

Mohajeri, Soraya; Aziz, Hamidi Abdul; Isa, Mohamed Hasnain; Zahed, Mohammad Ali; Adlan, Mohd Nordin

2010-04-15

320

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

321

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

SciTech Connect

The parameters necessary to model radionuclide transport in salt beds are identified and described. A proposed plan for disposal of the radioactive wastes generated by nuclear power plants is to store waste canisters in repository sites contained in stable salt formations approximately 600 meters below the ground surface. Among the principal radioactive wastes contained in these canisters will be radioactive isotopes of neptunium, americium, uranium, and plutonium along with many highly radioactive fission products. A concern with this form of waste disposal is the possibility of ground-water flow occurring in the salt beds and endangering water supplies and the public health. Specifically, the research investigated the processes involved in the movement of radioactive wastes from the repository site by groundwater flow. Since the radioactive waste canisters also generate heat, temperature is an important factor. Among the processes affecting movement of radioactive wastes from a repository site in a salt bed are thermal conduction, groundwater movement, ion exchange, radioactive decay, dissolution and precipitation of salt, dispersion and diffusion, adsorption, and thermomigration. In addition, structural changes in the salt beds as a result of temperature changes are important. Based upon the half-lives of the radioactive wastes, he period of concern is on the order of a million years. As a result, major geologic phenomena that could affect both the salt bed and groundwater flow in the salt beds was considered. These phenomena include items such as volcanism, faulting, erosion, glaciation, and the impact of meteorites. CDM reviewed all of the critical processes involved in regional groundwater movement of radioactive wastes and identified and described the parameters that must be included to mathematically model their behavior. In addition, CDM briefly reviewed available echniques to measure these parameters.

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

1979-07-01

322

Science Education and Outreach: Forging a Path to the Future  

NASA Astrophysics Data System (ADS)

The International Year of Astronomy and the Year of Science provide singular opportunities to focus public attention on science in general and the universe in particular in 2009. But what happens on January 1, 2010? How can the science and science education communities build on the initiatives and successes of 2009 to create sustainable programs and efforts to continue to advance science education and literacy objectives for the longer term? The presenter will relate how these questions will be addressed at the annual meeting of the Astronomical Society of the Pacific in Millbrae, California, September 12-16, and how the meeting will provide an opportunity for the science, astronomy, and science education and outreach communities to contribute to the discussion and to share their answers and perspectives with the larger community, and to identify ways in which we can forge that future path together.

Manning, James G.

2009-05-01

323

Formulation and implementation of a practical algorithm for parameter estimation with process and measurement noise  

NASA Technical Reports Server (NTRS)

A new formulation is proposed for the problem of parameter estimation of dynamic systems with both process and measurement noise. The formulation gives estimates that are maximum likelihood asymptotically in time. The means used to overcome the difficulties encountered by previous formulations are discussed. It is then shown how the proposed formulation can be efficiently implemented in a computer program. A computer program using the proposed formulation is available in a form suitable for routine application. Examples with simulated and real data are given to illustrate that the program works well.

Maine, R. E.; Iliff, K. W.

1980-01-01

324

Removing arsenic from coal under ultrasonic and microwave radiation: The influence of processing parameter  

SciTech Connect

Arsenic is one of the trace elements in coal that we are most concerned about because of its toxicity and environmental persistence. Poisoning is endemic in China and is widespread and locally very severe, which is receiving increased attention throughout the world. In this study, an oxidation method was applied for removing arsenic from two Chinese coals (Yima and Datong) under ultrasonic and microwave radiation. There are many processing parameters that impact the effect of removing arsenic from coal: power of ultrasonic, time in ultrasonic, time in microwave radiation, and the concentration of coal, and these were considered with several levels in this article.

Mi, J.; Ren, J.; Zhang, H.J.; Xie, K.C. [Taiyuan University, Taiyuan (China)

2008-07-01

325

Formulation of Dacarbazine-loaded Cubosomes—Part II: Influence of Process Parameters  

Microsoft Academic Search

The purpose of this study is to investigate the combined influence of process parameters (independent variables) such as homogenization\\u000a speed (X\\u000a 1), duration (X\\u000a 2), and temperature (X\\u000a 3) during the preparation of dacarbazine-loaded cubosomes. Box–Behnken design was used to rationalize the influence of these\\u000a three factors on two responses, namely particle size (Y\\u000a 1) and encapsulation efficiency (Y\\u000a 2).

Di Bei; Jacob Marszalek; Bi-Botti C. Youan

2009-01-01

326

Effect of sintering process parameters on the properties of 3Y-PSZ ceramics  

NASA Astrophysics Data System (ADS)

The effect of sintering process parameters on the properties of 3 mol% yttria partially stability zirconia (3Y-PSZ) ceramics has been investigated. The relative density of the sintered pellet rapidly increases from 70.5 to 93.6% with rose temperature from 1473 to 1573 K. In addition, the relative density only slightly increases from 94.9 to 96.6 %, when rose sintered temperature from 1573 to 1773 K. This result shows that no significant influence on the densification behavior when sintering at 1573 to 1773 K for 2 h. The Vickers hardness and toughness also increase with the sintered temperature.

Chu, H. L.; Wang, C. L.; Lee, H. E.; Sie, Y. Y.; Chen, R. S.; Hwang, W. S.; Wang, M. C.

2013-12-01

327

A study of process parameters of LSM and LSM–YSZ composite cathode films prepared by screen-printing  

Microsoft Academic Search

A screen-printing technique was developed to fabricate porous cathode film for solid oxide fuel cells. Several key process parameters such as the selection of binders, the mesh of screen, sintering temperature and sintering time were investigated and reported. SEM results showed that the selected process parameters exerted obvious influences on the structure of the screen-printed cathode film. Impedance spectra data

Jinhua Piao; Kening Sun; Naiqing Zhang; Shen Xu

2008-01-01

328

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

PubMed

Optimization of productivity and economics of industrial bioprocesses requires characterization of interdependencies between process parameters and process performance. In the case of penicillin production, as in other processes, process performance is often closely interlinked with the physiology and morphology of the organism used for production. This study presents a systematic approach to efficiently characterize the physiological effects of multivariate interdependencies between bioprocess design parameters (spore inoculum concentration, pO2 control level and substrate feed rate), morphology, and physiology. Method development and application was performed using the industrial model process of penicillin production. Applying traditional, statistical bioprocess analysis, multivariate correlations of raw bioprocess design parameters (high spore inoculum concentration, low pO2 control as well as reduced glucose feeding) and pellet morphology were identified. A major drawback of raw design parameter correlation models; however, is the lack of transferability across different process scales and regimes. In this context, morphological and physiological bioprocess modeling based on scalable physiological parameters is introduced. In this study, raw parameter effects on pellet morphology were efficiently summarized by the physiological parameter of the biomass yield per substrate. Finally, for the first time to our knowledge, the specific growth rate per spore was described as time-independent determinant for switching from pellet to disperse growth during penicillin production and thus introduced as a novel, scalable key process parameter for pellet morphology and process performance. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:689-699, 2014. PMID:24616429

Posch, Andreas E; Herwig, Christoph

2014-05-01

329

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

NASA Technical Reports Server (NTRS)

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

Brennecke, M. W.

1978-01-01

330

Response Surface Method for the Rapid Design of Process Parameters in Tube Hydroforming  

NASA Astrophysics Data System (ADS)

This paper deals with the optimization of tube hydroforming parameters in order reduce defects which may occur at the end of forming process such as necking and wrinkling. We propose a specific methodology based on the coupling between an inverse method for the rapid simulation of tube hydroforming process, and a Response Surface Method based on diffuse approximation. The response surfaces are built using Moving Least Squares approximations and constructed within a moving region of interest which moves across a predefined discrete grid of authorized experimental designs. An application of hydroforming of a bulge from aluminium alloy 6061-T6 tubing has been utilized to validate our methodology. The final design is validated with ABAQUS Explicit Dynamic commercial code.

Chebbah, M. S.; Naceur, H.; Hecini, M.; Belouettar, S.

2007-05-01

331

Cardiac sensitivity in children: Sex differences and its relationship to parameters of emotional processing.  

PubMed

In adults, the level of ability to perceive one's own body signals plays an important role for many concepts of emotional experience as demonstrated for emotion processing or emotion regulation. Representative data on perception of body signals and its emotional correlates in children is lacking. Therefore, the present study investigated the cardiac sensitivity of 1,350 children between 6 and 11 years of age in a heartbeat perception task. Our main findings demonstrated the distribution of cardiac sensitivity in children as well as associations with interpersonal emotional intelligence and adaptability. Furthermore, independent of body mass index, boys showed a significantly higher cardiac sensitivity than girls. We conclude that cardiac sensitivity in children appears to show weaker but similar characteristics and relations to emotional parameters as found in adults, so that a dynamic developmental process can be assumed. PMID:24810627

Koch, Anne; Pollatos, Olga

2014-09-01

332

Processing parameters associated with scale-up of balloon film production  

NASA Technical Reports Server (NTRS)

A method is set forth for assessing strain-rate profiles that can be used to develop a scale-up theory for blown-film extrusion. Strain rates are evaluated by placing four ink dots on the stalk of an extruded bubble to follow the displacements of the dots as a function of time. The instantaneous Hencky strain is obtained with the displacement data and plotted for analysis. Specific attention is given to potential sources of error in the distance measurements and corrections for these complex bubble geometries. The method is shown to be effective for deriving strain-rate data related to different processing parameters for the production of balloon film. The strain rates can be compared to frostline height, blow-up ratio, and take-up ratio to optimize these processing variables.

Simpson, D. M.; Harrison, I. R.

1993-01-01

333

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

334

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

SciTech Connect

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

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

2008-08-04

335

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

PubMed Central

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

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

2011-01-01

336

The influence of formulation and manufacturing process parameters on the characteristics of lyophilized orally disintegrating tablets.  

PubMed

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

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

2011-01-01

337

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.

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

2013-01-01

338

Parameters and the analytic process: a contribution to the theory of the "mature transference".  

PubMed

This case presentation deals with a patient whose preoedipally and oedipally determined deficit in directing libido and aggression toward the world, and resulting resistance to the analytic process, required the use of a "reducible" parameter designed to help him harness libido and aggression in the service of intellectual interest. The peculiar conformation of the patient's Oedipus complex, superimposed on a developmental deficit, led to profound resistance to genetic oedipal and preoedipal interpretations of the paternal and maternal transferences, respectively. The resistance took the form of an avowed lack of intellectual interest in the analytic work which paralleled his lack of interest both in his career and in his interpersonal relationships. The use of a technical parameter involving the provision of advice on an issue of pressing concern and a subsequent "preinterpretive enactment" dealing with the nature of psychoanalytic interpretation were instrumental in securing a "mature transference" (Stone, 1961) and in controlling the resistance-based regression. Via the instrumentality of the parameter, the case provides a concrete exemplification of Kanzer's (1975, p. 49) claim that "even the patient's antagonism toward therapy. . . may play a constructive part in the treatment." PMID:3988571

Fields, M

1985-01-01

339

Measurements of gas parameters in plasma-assisted supersonic combustion processes using diode laser spectroscopy  

SciTech Connect

We report a procedure for temperature and water vapour concentration measurements in an unsteady-state combustion zone using diode laser absorption spectroscopy. The procedure involves measurements of the absorption spectrum of water molecules around 1.39 {mu}m. It has been used to determine hydrogen combustion parameters in M = 2 gas flows in the test section of a supersonic wind tunnel. The relatively high intensities of the absorption lines used have enabled direct absorption measurements. We describe a differential technique for measurements of transient absorption spectra, the procedure we used for primary data processing and approaches for determining the gas temperature and H{sub 2}O concentration in the probed zone. The measured absorption spectra are fitted with spectra simulated using parameters from spectroscopic databases. The combustion-time-averaged ({approx}50 ms) gas temperature and water vapour partial pressure in the hot wake region are determined to be 1050 K and 21 Torr, respectively. The large signal-to-noise ratio in our measurements allowed us to assess the temporal behaviour of these parameters. The accuracy in our temperature measurements in the probed zone is {approx}40 K. (laser applications and other topics in quantum electronics)

Bolshov, Mikhail A; Kuritsyn, Yu A; Liger, V V; Mironenko, V R [Institute for Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow region (Russian Federation); Leonov, S B; Yarantsev, D A [Institute of Thermal Physics of Extreme States, Associated Institute of High Temperaturs, Russian Academy of Sciences (Russian Federation)

2009-09-30

340

Optimization of microcrystalline silicon thin film solar cell isolation processing parameters using ultraviolet laser  

NASA Astrophysics Data System (ADS)

This study used ultraviolet laser to perform the microcrystalline silicon thin film solar cell isolation scribing process, and applied the Taguchi method and an L 18 orthogonal array to plan the experiment. The isolation scribing materials included ZnO:Al, AZO transparent conductive film with a thickness of 200 nm, microcrystalline silicon thin film at 38% crystallinity and of thickness of 500 nm, and the aluminum back contact layer with a thickness of 300 nm. The main objective was to ensure the success of isolation scribing. After laser scribing isolation, using the minimum scribing line width, the flattest trough bottom, and the minimum processing edge surface bumps as the quality characteristics, this study performed main effect analysis and applied the ANOVA (analysis of variance) theory of the Taguchi method to identify the single quality optimal parameter. It then employed the hierarchical structure of the AHP (analytic hierarchy process) theory to establish the positive contrast matrix. After consistency verification, global weight calculation, and priority sequencing, the optimal multi-attribute parameters were obtained. Finally, the experimental results were verified by a Taguchi confirmation experiment and confidence interval calculation. The minimum scribing line width of AZO (200 nm) was 45.6 ?m, the minimum scribing line width of the microcrystalline silicon (at 38% crystallinity) was 50.63 ?m and the minimum line width of the aluminum thin film (300 nm) was 30.96 ?m. The confirmation experiment results were within the 95% confidence interval, verifying that using ultraviolet laser in the isolation scribing process for microcrystalline silicon thin film solar cell has high reproducibility.

Kuo, Chung-Feng Jeffery; Tu, Hung-Min; Liang, Shin-Wei; Tsai, Wei-Lun

2010-09-01

341

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

NASA Astrophysics Data System (ADS)

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

Inoue, Jun-ichi

2010-06-01

342

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

343

Kesan Penggunaan Jenis Tepung terhadap Kelikatan dan Parameter Pemprosesan Produk Goreng Bersalut (Effect of Flour Type on the Viscosity and Processing Parameter of a Fried Coated Product)  

Microsoft Academic Search

This study was done to determine the effect of using wheat, rice and sago flour at two different flour : water ratio on the viscosity and processing parameters of battered, fried banana. Batter was prepared by mixing wheat, rice and sago flour with water at two ratios of 1 : 1 and 1 : 2 (flour : water). Banana (Musa

MEUTIA SANDRA; MOHAMAD YUSOF MASKAT; AIDA WAN; AMINAH ABDULLAH

344

An analysis of cavity growth during open-die hot forging of Ti-6Al-4V  

NASA Astrophysics Data System (ADS)

The effect of local deformation conditions on the cavitation behavior of Ti-6Al-4V during open-die forging was quantified using optical metallography and continuum finite-element-method (FEM) analysis of pancake forgings. The observations were interpreted using meso- and microscopic-scale models, which were used to predict the average cavity size as well the size of the largest cavities. The mesoscale model gave excellent predictions of the average cavity size at different locations of the workpiece, but grossly underestimated the size of the largest cavities by an order of magnitude. On the other hand, the micromechanical model, which accounted for the effect of local colony orientation on cavity growth, was capable of predicting the size of the largest cavities very well. Because the large cavities are the most deleterious with respect to subsequent processing and service performance, it was concluded that micromechanical models should be used to design primary hot working processes in order to minimize the size and number of such cavities.

Nicolaou, P. D.; Semiatin, S. L.

2005-06-01

345

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

346

Baseline Water Quality Data Inventory and Analysis Valley Forge National Historical Park. Volume I of III.  

National Technical Information Service (NTIS)

This document presents the results of surface-water-quality data retrievals for Valley Forge National Historical Park from six of the United States Environmental Protection Agency's (EPA) national databases: (1) Storage and Retrieval (STORET) water qualit...

2003-01-01

347

Machinability of Microalloyed Bar Steels for Hot Forged Components without Subsequent Heat Treatment.  

National Technical Information Service (NTIS)

Machinability of microalloyed bar steels for hot forged components without subsequent heat treatment is investigated in turning and drilling. Machinability in turning of ferrite-pearlite microalloyed steels is equivalent to that of quenched and tempered s...

T. Sampei T. Shiraga K. Matsumoto S. Ishizaki H. Kido

1990-01-01

348

Development of High-Toughness Mircoalloyed Steel Bar for Hot Forged Components without Subsequent Heat Treatment,  

National Technical Information Service (NTIS)

To achieve a wide application of microalloyed steel bar for hot forged components without subsequenct heat treatment, improvement of toughness was discussed, and microalloyed steel with a ferritic-pearlitic structure and with a low carbon bainitic structu...

T. Shiraga K. Matsumoto S. Suzuki M. Ishiguro H. Kido

1988-01-01

349

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

350

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

351

A study of double exposure process design with balanced performance parameters for line/space applications  

NASA Astrophysics Data System (ADS)

As the semiconductor fabrication groundrule has reached the 32nm node, in general there are several possible approaches for the photolithography solution such as the double exposure with 1.35 NA immersion, the high refractive index immersion, the extremely ultra violet (EUV) lithography, nanoimprint lithography etc. Among the four, the easiest approach seems to be the double exposure method at an effective numerical aperture (NA) of 1.35. However, there are still challenges in the design and optimization of the process, such as, the use of appropriate illumination condition, the choice of a good photoresist, and the design of an optical proximity correction (OPC) strategy. Besides these considerations, there is a question as whether we really need the double etch process. To study the double exposure mechanism, we have used a 248 nm deep-UV exposure tool and several well chosen photoresist (one is for Space application and the other is for Line application) to study the photo performance parameters in the merge of two photo exposures. At a numerical aperture (NA) around 0.7, the minimum groundrule we can achieve is the one for a 75 nm logic process with minimum pitch around 220 nm. One approach will be that the features with pitches wider than 440 nm are completed in a single exposure, which includes various isolated lines and spaces, line and space ends, two-dimensional structures, etc. This strategy essentially puts the single exposure pattern under the 0.18 um logic like pitches where mild conventional illumination can produce a balanced performance. Under typical illumination conditions, the photolithographic process under 0.18 um like ground rule is well understood and the optical proximity correction is not complicated. The remaining issues are in the dense pitches, where the double exposure kicks in. We have demonstrated that the double exposure with single development can achieve a process window large enough for a 75 nm logic like process and the OPC behavior such as line through pitch is manageable although OPC correction strategy may require substantial improvement to accommodate two individual exposures. In this paper, we will demonstrate the result of our study of the basic photolithographic performance indicators, such as the exposure latitude (EL), the depth of focus (DOF), the CD through pitch, the line edge roughness (LER) and the mask error factor (MEF) for the optimized process. And we will discuss the choice of photoresists for this special application. It seems that a photoresist with a balanced performance for both the line and space is necessary to realize a good double exposure process. In this paper, we will also present our simulation result of effective resist diffusion length to explore the limit of such approach.

Zhu, Jun; Wu, Peng; Wu, Qiang; Ding, Hua; Li, Xin; Sun, Changjiang

2007-03-01

352

Self-sustaining smoldering combustion for NAPL remediation: laboratory evaluation of process sensitivity to key parameters.  

PubMed

Smoldering combustion has been introduced recently as a potential remediation strategy for soil contaminated by nonaqueous phase liquids (NAPLs). Published proof-of-concept experiments demonstrated that the process can be self-sustaining (i.e., requires energy input only to start the process) and achieve essentially complete remediation of the contaminated soil. Those initial experiments indicated that the process may be applicable across a broad range of NAPLs and soils. This work presents the results of a series of bench-scale experiments that examine in detail the sensitivity of the process to a range of key parameters, including contaminant concentration, water saturation, soil type, and air flow rates for two contaminants, coal tar and crude oil. Smoldering combustion was observed to be self-sustaining in the range 28,400 to 142,000 mg/kg for coal tar and in the range 31,200 to 104,000 mg/kg for crude oil, for the base case air flux. The process remained self-sustaining and achieved effective remediation across a range of initial water concentrations (0 to 177,000 mg/kg water) despite extended ignition times and decreased temperatures and velocities of the reaction front. The process also exhibited self-sustaining and effective remediation behavior across a range of fine to coarse sand grain sizes up to a threshold maximum value between 6 mm and 10 mm. Propagation velocity is observed to be highly dependent on air flux, and smoldering was observed to be self-sustaining down to an air Darcy flux of at least 0.5 cm/s for both contaminants. The extent of remediation in these cases was determined to be at least 99.5% and 99.9% for crude oil and coal tar, respectively. Moreover, no physical evidence of contamination was detected in the treatment zone for any case where a self-sustaining reaction was achieved. Lateral heat losses to the external environment were observed to significantly affect the smoldering process at the bench scale, suggesting that the field-scale lower bounds on concentration and air flux and upper bound on grain size were not achieved; larger scale experiments and field trials where lateral heat losses are much less significant are necessary to define these process limits for the purposes of field application. This work provides valuable design data for pilot field trials of both in situ and ex situ smoldering remediation applications. PMID:21351763

Pironi, Paolo; Switzer, Christine; Gerhard, Jason I; Rein, Guillermo; Torero, Jose L

2011-04-01

353

New manufacturing techniques of large forged shell rings for pressure vessels  

Microsoft Academic Search

A 250 ton hollow ingot was made for experimental purposes so that the properties of a large-sized hollow ingot could be simulated.\\u000a The investigation results indicated that this ingot was suitable for forged shell rings of nuclear reactor pressure vessels\\u000a (RPV). They were used in the manufacture of forged shell rings for an RPV of a 1300 MW type PWR

K. Saito; A. Namba; K. Aso; N. Abe; J. Nagai; A. Ejima

1987-01-01

354

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

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

355

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

356

Tailoring wet explosion process parameters for the pretreatment of cocksfoot grass for high sugar yields.  

PubMed

The pretreatment of lignocellulosic biomass is crucial for efficient subsequent enzymatic hydrolysis and ethanol fermentation. In this study, wet explosion (WEx) pretreatment was applied to cocksfoot grass and pretreatment conditions were tailored for maximizing the sugar yields using response surface methodology. The WEx process parameters studied were temperature (160-210 °C), retention time (5-20 min), and dilute sulfuric acid concentration (0.2-0.5 %). The pretreatment parameter set E, applying 210 °C for 5 min and 0.5 % dilute sulfuric acid, was found most suitable for achieving a high glucose release with low formation of by-products. Under these conditions, the cellulose and hemicellulose sugar recovery was 94 % and 70 %, respectively. The efficiency of the enzymatic hydrolysis of cellulose under these conditions was 91 %. On the other hand, the release of pentose sugars was higher when applying less severe pretreatment conditions C (160 °C, 5 min, 0.2 % dilute sulfuric acid). Therefore, the choice of the most suitable pretreatment conditions is depending on the main target product, i.e., hexose or pentose sugars. PMID:23709291

Njoku, S I; Ahring, B K; Uellendahl, H

2013-08-01

357

Influence of process parameters on phosphorus recovery by struvite formation from urine.  

PubMed

Batch experiments were conducted to examine the influence of various process parameters on phosphorus (P) recovery by struvite formation from urine. The results showed that the Mg/P molar ratio is one of the most important parameters affecting P recovery. The Mg/P molar ratio of 1.3 was found the most reasonable for struvite formation, and the P removal efficiency reached more than 96.6%. An increase in pH of urine solutions from 8.7 to 10.0 did not significantly affect P removal, but the quality of crystal formed at pH 10.0 was poor based on scanning electron microscopy analysis. A longer mixing time positively affected struvite formation, and compared to without mixing, the P removal efficiency increased from 72.7 to 97.3% after 5 min of mixing. The addition of seed material had no influence on the P removal efficiency, but contributed to the formation of struvite clusters. PMID:24334893

Liu, Xiaoning; Hu, Zhengyi; Zhu, Chunyou; Wen, Guoqi; Meng, Xianchao; Lu, Jia

2013-01-01

358

Determination of Optimal Technological Parameters of a Compaction Process: Case Study  

NASA Astrophysics Data System (ADS)

Pelletizing as a complicated compaction process is under continuous improvement. One of the problems - determination of optimal technological parameters to attain a sufficiently high density of pellets - is solved in this paper. The statistical model of density depending on four technological factors is built based on data obtained through a central composite design. Canonical analysis is used to find the stationary point, and as the received point is a saddle point, the optimal setting is determined by means of ridge analysis. Special attention is paid to the uncertainty associated with the indirect measurement of the pellet density. Substantial differences in the density exist between pellets created under the same conditions, and especially the type-A uncertainty must be taken into consideration

Jarošová, E.; Kureková, E.

2013-01-01

359

Influence of processing parameters on synthesis of nano-sized AlN powders  

NASA Astrophysics Data System (ADS)

The synthesis feasibility of nanocrystalline AlN via a modified carbothermal reduction-nitridation route from a low-temperature combustion precursor containing alumina and carbon was studied in detail. The spotlight was focused on optimizing various process parameters such as ignition temperature, the amount of NH 4NO 3 as combustion aids, type of monose (glucose, starch and glucose) and calcinations temperature. The powders were characterized for specific surface area, XRD, TEM and DTA/TG thermal analysis. The results showed that nano-sized single-phase AlN was obtained regardless of the addition amount of NH 4NO 3, ignition temperature and the type of carbon source introduced in the precursor solution. The nitridation temperature employing an as-burned precursor was 1400-1500°C lower than that in the conventional CRN route (>1600°C).

Kuang, JiaCai; Zhang, ChangRui; Zhou, XinGui; Wang, SiQing

2004-03-01

360

Combustion synthesis and effects of processing parameters on physical properties of {alpha}-alumina  

SciTech Connect

Fine particle porous {alpha}-alumina has been prepared by a wet chemical method of combustion synthesis using an aqueous precursor containing aluminum nitrate (oxidizer) and carbohydrazide, an organic fuel as starting materials. The aluminum nitrate and carbohydrazide were reacted exothermically at 400--600 C. The synthesis of {alpha}-alumina ({alpha}-Al{sub 2}O{sub 3}) was used as a model for understanding the effects of processing parameters on physical properties such as surface area, average pore size, and residual carbon content. The porous powders were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area analysis and elemental analysis. The decomposition of the starting materials was investigated using differential thermal and thermogravimetric analyses (DTA/TGA). It has been shown that the furnace temperature, fuel/oxidizer ratio, and precursor water content can be tailored to produce powders with different physical properties.

Collins, M.V.; Hirschfeld, D.A.; Shea, L.E.

2000-01-04

361

Effects of process parameters on sheet resistance uniformity of fluorine-doped tin oxide thin films.  

PubMed

An alternative indium-free material for transparent conducting oxides of fluorine-doped tin oxide [FTO] thin films deposited on polyethylene terephthalate [PET] was prepared by electron cyclotron resonance - metal organic chemical vapor deposition [ECR-MOCVD]. One of the essential issues regarding metal oxide film deposition is the sheet resistance uniformity of the film. Variations in process parameters, in this case, working and bubbler pressures of ECR-MOCVD, can lead to a change in resistance uniformity. Both the optical transmittance and electrical resistance uniformity of FTO film-coated PET were investigated. The result shows that sheet resistance uniformity and the transmittance of the film are affected significantly by the changes in bubbler pressure but are less influenced by the working pressure of the ECR-MOCVD system. PMID:22221518

Hudaya, Chairul; Park, Ji Hun; Lee, Joong Kee

2012-01-01

362

Parameters of scalar resonances from the combined analysis of data on processes ?????, KK¯, ?? and J /? decays  

NASA Astrophysics Data System (ADS)

A combined analysis of data on the isoscalar S-wave processes ?????, KK¯, ?? and on decays J /?????, ?KK¯ from the DM2, Mark III, and BES II Collaborations is performed to study f0 mesons. The method of analysis is based on analyticity and unitarity and uses an uniformization procedure. In the analysis limited only to the multichannel ??-scattering data, two possible sets of parameters of the f0(500) were found: In both cases the mass was about 700 MeV but the total width was either about 680 or 1040 MeV. The extension of the analysis using only the DM2 and Mark III data on the J /? decays does not allow us to choose between these sets. However, the data from BES II on the di-pion mass distribution in the decay J /????+?- clearly prefer the wider f0(500) state. Spectroscopic implications from the results of the analysis are also discussed.

Surovtsev, Yurii S.; Bydžovský, Petr; Kami?ski, Robert; Lyubovitskij, Valery E.; Nagy, Miroslav

2014-02-01

363

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

364

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

NASA Technical Reports Server (NTRS)

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

Pindera, Marek-Jerzy; Salzar, Robert S.

1996-01-01

365

Deformation, recrystallization, strength, and fracture of press-forged ceramic crystals.  

NASA Technical Reports Server (NTRS)

Sapphire and ruby were very difficult to press-forge because they deformed without cracking only in a limited temperature range before they melted. Spinel crystals were somewhat easier and MgO, CaO, and TiC crystals much easier to forge. The degree of recrystallization that occurred during forging (which was related to the ease and type of slip intersections) varied from essentially zero in Al2O3 to complete (i.e., random polycrystalline bodies were produced) in CaO. Forging of bi- and polycrystalline bodies produced incoherent bodies as a result of grain-boundary sliding. Strengths of the forged crystals were comparable to those of dense polycrystalline bodies of similar grain size. However, forged and recrystallized CaO crystals were ductile at lower temperatures than dense hot-pressed CaO. This behavior is attributed to reduced grain-boundary impurities and porosity. Fracture origins could be located, indicating that fracture in the CaO occurs internally as a result of surface work hardening caused by machining.-

Rice, R. W.

1972-01-01

366

Forging convictions: the effects of active participation in a clinical trial.  

PubMed

This qualitative study explored non-specific influences on participation in, and outcomes of, a randomised controlled trial. It was nested within a single-blind clinical trial of western acupuncture which compared real acupuncture with two types of placebo control administered to National Health Service (NHS) patients awaiting hip and knee replacement surgery in England. Data collection (2004-2008) was based on narrative-style interviews and participant observation. The results indicate that trial recruitment and retention depend on a set of convictions forged largely as a result of contextual factors peripheral to the intervention, including the friendliness and helpfulness of research centre staff and status of the administering practitioner. These convictions also influence the reporting of the study outcomes, particularly if participants experience uncertainties when choosing an appropriate response. The findings suggest that participants in clinical trials are actively involved in shaping the research process, rather than passive recipients of treatment. Thus the outcomes of trials, notably those involving contact interventions, should be regarded not as matters of fact, but as products of complex environmental, social, interpretive and biological processes. In this paper, we develop and present a 'theory of active research participation' which offers a framework for understanding the impact of non-specific processes in clinical trials. PMID:21636195

Scott, Clare; Walker, Jan; White, Peter; Lewith, George

2011-06-01

367

Influence of process parameters on yield and composition of gluten fractions obtained in a laboratory scale dough batter procedure  

Microsoft Academic Search

The influence of process parameters during the dough formation step on wheat flour gluten agglomeration and composition in a laboratory scale gluten–starch separation process was studied. In the process, in which a dough was transformed into a batter then poured over a set of vibrating sieves (400, 250 and 125 ?m), increasing water contents, mixing times and speeds during dough

S. A Frederix; C. M Courtin; J. A Delcour

2004-01-01

368

Influence of material and process parameters on the development of necking and bursting in flange and tube hydroforming  

Microsoft Academic Search

Necking and bursting are current defects that appear and limit the flange and tube hydroforming processes. The linear stability analysis has been extended to 3D stress states in order to detect these defects during hydroforming processes. Numerical predictions are compared with experiments to illustrate the validity of the approach. In addition, the influence of material and process parameters on the

N. Boudeau; A. Lejeune; J. C. Gelin

2002-01-01

369

Processing parameter effect on the splat diameters of the droplets produced by liquid metal atomization using De Laval nozzle  

Microsoft Academic Search

Liquid metal atomization with De Laval nozzle is not a widely used technique to produce metallic powders. It appears as a versatile process to manufacture different particle sizes according to the processing parameters (gas pressure, melt nozzle diameter, De Laval nozzle diameter, etc.). However, few studies have focused on the understanding of the different stages of the process. During the

O. Khatim; M. P. Planche; L. Dembinski; Y. Bailly; C. Coddet

2010-01-01

370

Characterization Of An EBL System: The Influence Of Process Parameters On Thickness Resist And Engraving Shapes  

SciTech Connect

In LIGA process, the low flexibility due to the use of masks might be overcome using the electron beam of a scansion electron microscope (SEM) instead of the synchrotron radiation. In this way, through the vector control of the beam, it is possible to irradiate a specific path on the resist without using any mask. Anyway, it is important to remark that the Electron Beam Lithography (EBL) can not include all the applications of the X-ray LIGA technique but it could be a valid alternative only for some specific uses. In particular, some limits concerning the impression of high thickness resists are expected. An EBL system based on a SEM was recently implemented by the authors and some tests were carried out to characterize the device performances. Aim of this work is to asses the system performances in terms of maximum impressible thickness resist and shape of the engraved entities. Several tests were carried out by varying the resist thickness and the process parameters.

D'Urso, G.; Longo, M.; Ravasio, C.; Maccarini, G. [University of Bergamo-Dept. of Design and Technologies-Viale Marconi 5, Dalmine (Italy)

2011-01-17

371

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

372

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.

2014-01-01

373

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

374

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

375

Can standard surface EMG processing parameters be used to estimate motor unit global firing rate?  

NASA Astrophysics Data System (ADS)

The relations between motor unit global firing rates and established quantitative measures for processing the surface electromyogram (EMG) signals were explored using a simulation approach. Surface EMG signals were simulated using the reported properties of the first dorsal interosseous muscle in man, and the models were varied systematically, using several hypothetical relations between motor unit electrical and force output, and also using different motor unit firing rate strategies. The utility of using different EMG processing parameters to help estimate global motor unit firing rate was evaluated based on their relations to the number of motor unit action potentials (MUAPs) in the simulated surface EMG signals. Our results indicate that the relation between motor unit electrical and mechanical properties, and the motor unit firing rate scheme are all important factors determining the form of the relation between surface EMG amplitude and motor unit global firing rate. Conversely, these factors have less impact on the relations between turn or zero-crossing point counts and the number of MUAPs in surface EMG. We observed that the number of turn or zero-crossing points tends to saturate with the increase in the MUAP number in surface EMG, limiting the utility of these measures as estimates of MUAP number. The simulation results also indicate that the mean or median frequency of the surface EMG power spectrum is a poor indicator of the global motor unit firing rate.

Zhou, Ping; Zev Rymer, William

2004-06-01

376

The effect of filtering processes on surface roughness parameters and their correlation with the measured friction, Part II: porcelain tiles  

Microsoft Academic Search

It is known that surface roughness affects friction, but it is unclear which surface characteristics are better correlated with friction. Moreover, the filter process used in a surface roughness measurement affects the values of surface parameters and, therefore, affects surface representations. The effect of filter selection on the surface parameters of unglazed quarry tiles and their correlation with the measured

Wen-Ruey Chang

2000-01-01

377

The Flow Behavior and Microstructural Evolution of Ti-5Al-5Mo-5V-3Cr during Subtransus Isothermal Forging  

NASA Astrophysics Data System (ADS)

High-strength metastable ? alloys, for example, Ti-5Al-5Mo-5V-3Cr, have replaced steel as the material of choice for large components, such as the main truck beam on the latest generation of airframes. The production of these components is carried out by hot near-net-shape forging, during which process variable control is essential to achieve the desired microstructural condition and subsequent mechanical properties. The flow behavior and microstructural evolution during subtransus isothermal forging of Ti-5Al-5Mo-5V-3Cr has been investigated for two different starting microstructures and analysis has incorporated previously published results. The flow behavior, irrespective of initial microstructural condition, is found to be very similar at strains ?0.35. It is thought that this is due to a common microstructural state being reached, where dynamic recovery of the ? phase is the dominating deformation mechanism. At strains <0.35, the flow behavior is believed to be dominated by the morphology and volume fraction of the ? phase. Small globular ? particles are thought to have little effect on the flow behavior, while the observed flow softening is directly linked to the fragmentation of acicular ? precipitates.

Jones, N. G.; Dashwood, R. J.; Dye, D.; Jackson, M.

2009-08-01

378

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...

379

Process-parameter optimization of Sb 2 O 3 films in the ultraviolet and visible region for interferometric applications  

Microsoft Academic Search

The influence of different evaporation process parameters on the optical properties and constants of thin Sb2O3 films in the ultraviolet and visible region from 250 to 800 nm has been investigated. The most dominant parameters, namely the substrate temperature, rate of evaporation, and ambient oxygen pressure used during the deposition process and the post-annealing temperatures were optimised which resulted in

N. K. Sahoo; K. V. S. R. Apparao

1996-01-01

380

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

Microsoft Academic Search

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

Hasan Oktem; Tuncay Erzurumlu; Ibrahim Uzman

2007-01-01

381

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

382

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

383

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

384

Formulation Optimization and Processing Parameter Establishment of Canned Chicken in Kacangma Herbal Soup (Pengoptimaan Formulasi dan Pembangunan Parameter Pemprosesan untuk Ayam Berkaleng dalam Sup Herba Kacangma)  

Microsoft Academic Search

The formulation of chicken in kacangma herbal soup, a traditional delicacy of Sarawak was developed. Processing parameters for the canned product was established. The product was canned and retorted at 121°C in an overpressure retort to achieve commercial sterility. A three-component constrained mixture according to a symmetrical-simplex interior design was used to determine the optimum formulation. Result showed that a

CHUA HUN PIN; AMINAH ABDULLAH

385

Effect of formulation and manufacturing parameters on process cheese food functionality--I. Trisodium citrate.  

PubMed

The objective of this research was to use a Rapid Visco Analyzer to study the effect of natural cheese age, trisodium citrate (TSC) concentration, and mixing speed on process cheese food (PCF) functionality. In this study 3 replicates of natural cheese were manufactured, and a portion of each cheese was subjected to 6 different PCF manufacturing treatments at 2, 4, 6, 12, and 18 wk of ripening. These treatments were factorial combinations of 3 levels of TSC (i.e., 2.0, 2.5, and 3.0%) and 2 mixing speeds during manufacture (450 and 1,050 rpm). Functional properties of the PCF evaluated included manufacturing properties [apparent viscosity after manufacture (VAM)], unmelted textural properties (firmness), melted cheese flow properties [hot apparent viscosity (HAV)], and cheese thickening during cooling [time at 5000 cP (T5)]. All 4 parameters (VAM, firmness, HAV, and T5) were significantly affected by natural cheese age and mixing speed, whereas VAM, HAV, and T5 were also significantly influenced by the amount of TSC. The VAM and firmness decreased as cheese age increased, whereas T5 values increased as cheese age increased. Similarly, VAM, HAV, and firmness values increased because of the increased mixing speed, whereas T5 values decreased. The age x mixing speed interaction was significant for VAM and firmness. The age x concentration of the TSC interaction term was significant for VAM, whereas the age x age x TSC concentration term was significant for HAV. The results demonstrate that natural cheese age, mixing speed during manufacture, and concentration of TSC have a significant impact on process cheese functionality. PMID:16772554

Purna, S K Garimella; Pollard, A; Metzger, L E

2006-07-01

386

Influence of process parameters on the weld lines formation in rapid heat cycle molding  

NASA Astrophysics Data System (ADS)

The insufficient entanglement of the molecular chains at the v-notch of a weld line impairs the mechanical strength and the surface quality of a plastic product. The rapid heat cycle molding technology (RHCM) has been recently used to enhance surface appearance of the parts, by thermally cycling the mold surface temperature. The mold temperature is the key of RHCM technology because it significantly affects productivity, energy efficiency and the quality of the final polymer part. In this work the influence of mold temperature on the weld lines depth and roughness were studied. Three different materials were tested. To investigate the influence of process parameters, a special mold insert was designed and manufactured. Weld lines geometry and roughness were quantitatively characterized by means of a profilometer. Experimental results show that is possible to increase the temperature to 10° C lower than the glass transition to obtain a high-gloss parts without weld lines with a significant reduction of cycle time and energy consumption.

Fiorotto, Marco; Lucchetta, Giovanni

2011-05-01

387

Influence of formulation and process parameters on pellet production by powder layering technique.  

PubMed

The goal of the present study was to evaluate the influence of the formulation and operating conditions on pellet preparation by pan technique. To this end, a new pelletization process, typified by the application of powdered drug on sugar-based cores using the GS coating system was studied. Inert cores were intermittently treated with micronized drug powder and adhesive solution. This treatment led to the formation of multiple layers of drug particles around an inert core resulting in the production of pellets that can further be coated by different polymers to obtain modified release formulations. Different procedures have been used to evaluate a series of important parameters such as initial core weight; speed of powder application; speed, type, and position of the atomizers; atomization degree; temperature; and air cap. Good yield of drug layering was obtained by adjusting the quantity of both the drug powder to apply and the binder solution. Pellets obtained following the optimal operating conditions (defined in a pre-formulation study) were film coated with the acrylic polymer Eudragit L30D in order to produce a model formulation consisting of enteric polymer-coated pellets containing ibuprofen. During its preparation, the formulation showed no degradation of the drug; moreover, a low percentage of residual humidity was obtained, indicating that this system is very efficient for the production of highly stable formulations. This study showed the good performance of the GS automated pan-coating system in obtaining enteric coated pellets prepared by powder layering technique using aqueous solutions. PMID:14727842

Nastruzzi, C; Cortesi, R; Esposito, E; Genovesi, A; Spadoni, A; Vecchio, C; Menegatti, E

2000-01-01

388

Process Parameters in Resistance Projection Welding for Optical Transmission Device Package  

NASA Astrophysics Data System (ADS)

The effects of main process parameters and electrode materials on joint quality (charging voltage and operating force) were investigated using detailed metallurgical examination and the helium leak test. The electrode materials used for resistance projection welding were brass and Cr-Cu alloy. The TO-Can components (cap and header) were nickel-coated SPCC steel. The results indicated that when the operating pressure increased, the electrode displacement increased, causing expulsion and distortion of the welds. The nugget area increased with the increase of charging voltage; however, it decreased with the increase of operating pressure. Results from the optical microscopy analysis showed that a larger acceptable welding range was achieved by using Cr-Cu electrodes. TO-Can in the acceptable and expulsion range successfully passed the helium leak rate of less than 5 × 10-8 mbar L/s. For commercial purposes, where dimensions have to be exact and without deformation, the TO-Can components produced in the expulsion zone cannot be used.

Huang, Her-Yueh; Tseng, Kuang-Hung

2011-03-01

389

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

390

Mdodeling a nitrite-dependent anaerobic methane oxidation process: parameters identification and model evaluation.  

PubMed

Nitrite-dependent anaerobic methane oxidation (n-damo) is a recently discovered process that is intermediated by n-damo bacteria that oxidize methane with nitrite to generate nitrogen gas. In this work, a kinetic model based on Monod type kinetics and diffusion-reaction model was developed to describe the bioprocess. Some key kinetic parameters needed in the model were obtained from a series of batch activity tests and a sequencing batch reactor (SBR) operation over 100 days. The growth rate, decay rate, methane affinity constant, nitrite affinity constant and inhibition constant were 0.0277±0.0022 d(-1), 0.00216±0.00010 d(-1), 0.092±0.005 mmol L(-1), 0.91±0.09 mmol L(-1) and 4.1±0.5 mmol L(-1) for n-damo bacteria at 30 °C, respectively. The results showed that the model could simulate actual performance of the SBR in the first 76 days, that methane was not a limiting factor at atmospheric pressure for its high affinity, and that the optimum nitrite concentration was 1.92 mmol L(-1). PMID:23994967

He, Zhanfei; Cai, Chen; Geng, Sha; Lou, Liping; Xu, Xiangyang; Zheng, Ping; Hu, Baolan

2013-11-01

391

Effects of process parameters on the properties of biocompatible ibuprofen-loaded microcapsules.  

PubMed

The objective of this study was to obtain an optimum formulation for microencapsulating Ibuprofen. This was achieved by investigating various factors which influenced the microcapsule size. Considering Ibuprofen as a lipophilic model drug, biocompatible Ibuprofen-loaded microcapsules in the size range of 20-60microm were prepared by the water in oil emulsion-solvent evaporation method. An aqueous surfactant phase was used as the continuous external phase (W), a biocompatible organic solvent dissolving Ibuprofen was used as oil phase (O), in addition with a low boiling solvent. The biocompatible polymeric microcapsule membrane was composed of Eudragit RSPO or Ethylcellulose. The influence of various process parameters, such as the volatile organic solvent, the oily core, the stirring rate, on the characteristics of microcapsules was investigated. The encapsulation yield of Ibuprofen close to 100%, whatever the polymer type, was determined by UV-vis experiments, in accordance with the results obtained by (13)C NMR spectroscopy. An innovative technique, DSC-based thermoporosimetry, was used for the estimation of the loading rate of Ibuprofen. The results indicated that this developed analytical method had to be improved since DSC-transitions accounted to free and enclosed Ibuprofen were observed and altered the accuracy of the results. PMID:19084583

Valot, P; Baba, M; Nedelec, J-M; Sintes-Zydowicz, N

2009-03-18

392

The effects of process parameters on spatter deposition in laser percussion drilling  

NASA Astrophysics Data System (ADS)

This paper reports on the characterisation and analysis of spatter deposition during laser drilling in Nimonic 263 alloy for various laser processing parameters using a fibre-optic delivered 400 W Nd:YAG laser. The principal findings are a large proportion of the spatter (approx. > 70%) was deposited due to the initial laser pulses (before beam breakthrough) required to drill a through-hole. Short pulse widths, low peak powers and high pulse frequencies generated smaller spatter deposition areas. At high pulse frequencies, the spatter distribution/thickness can be altered as a result of laser-ejected material interaction. Focal plane positions between -0.5 and +1.5 mm produced relatively similar spatter areas of about 14 mm2. As a result of the reduction in the material removed per pulse, a longer focal length of 160 mm generated smaller areas of spatter deposition in comparison to a shorter focal length of 120 mm. In addition, a generic relationship between the spatter area and dentrance/ dexit with increasing total laser energy has been established.

Low, D. K. Y.; Li, L.; Byrd, P. J.

2000-07-01

393

Effect of wheat processing on rumen characteristics and rumen parameters in Holstein-Friesian calves.  

PubMed

In this experiment, effect of wheat processing on rumen conditions and development were investigated. Fifty-six neonatal Holstein-Friesian calves (22 male and 34 female) were fed calf starters and post-weaning diets containing 35 (pre-weaning) and 21.90% (post-weaning) popped wheat (PW), steam-flaked wheat (SFW), dry-rolled wheat (DRW) or ground wheat (GW) till 12?weeks of age. Calves were weaned at the end of 9th week, and a post-weaning-specific starter diets were fed for 1?month. Rumen liquor was analysed in days 30, 60 and 90 of the experiment to determine volatile fatty acids (VFA), pH and ammonia nitrogen concentrations. Twelve male calves (three calves/treatment) were slaughtered, and digestive tract was emptied. Forestomach empty weight and rumen parameters were assessed. Results indicated that calves received PW had the highest total VFA, acetate, propionate, butyrate, ammonia nitrogen, rumen wall thickness, papilla width and density. Calves fed DRW experienced the lowest rumen pH throughout the experiment probably because high proportion of fine particles in GW. Calves consuming PW apparently had more functional rumen in comparison with other groups. PMID:22882188

Mirghaffari, S S; Karkoodi, K; Mirza-Aghazadeh, A; Maheri-Sis, N

2012-08-11

394

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

PubMed

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

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

2010-04-01

395

The influence of VAR processes and parameters on white spot formation in Alloy 718  

SciTech Connect

Significant progress has occurred lately regarding the classification, characterization, and formation of white spots during vacuum arc remelting (VAR). White spots have been generally split into three categories: discrete white spots, which are believed to be associated with undissolved material which has fallen in from the shelf, crown, or torus regions; dendritic white spots, usually associated with dendrite clusters having fallen from the electrode; and solidification white spots, believed to be caused by local perturbations in the solidifications conditions. Characteristics and proposed formation mechanisms of white spots are reviewed and discussed in context of physical processes occurring during VAR, such as fluid flow and arc behavior. Where possible, their formation mechanisms will be considered with respect to specific operating parameters. In order to more fully understand the formation of solidification white spots, an experimental program has been begun to characterize the solidification stability of Alloy 718 and variants with respect to changes in growth rate and thermal environment. A description of the experimental program and preliminary results are included.

Damkroger, B.K.; Kelley, J.B.; Schlienger, M.E.; Van Den Avyle, J.A.; Williamson, R.L.; Zanner, F.J.

1994-05-01

396

Effect of Process Parameters on the Structure and Properties of Galvanized Sheets  

NASA Astrophysics Data System (ADS)

The effect of galvanizing parameters on the structure (spangle size and coating microstructure) and properties (formability and corrosion resistance) of galvanized sheets was studied in a hot dip process simulator (HDPS) in a conventional Pb bearing (0.08-0.10%) zinc bath by varying zinc bath Al level (0.10-0.28%), bath temperature (718-743 K), dipping time (1.5-3.5 s), wiping gas flow rate (200-450 lpm), nozzle distance (15-17 mm) and wiping delay time (0.1-2.1 s). Al level in the range of 0.18-0.24% in combination with dipping time of 1.5-2.5 s and bath temperature of 718-733 K results in superior formability ( E cv: ~9.3 mm) of the composite (thickness: 0.8 mm). High post-dip cooling rates (~25 K/s) suppress spangle growth (spangle size: ~2 mm). The spangle size of the GI sheet strongly influences the corrosion rate which increases from 5.8 to 9.2 mpy with a decrease in spangle size from 17.5 to 3 mm. By controlling the Al level (0.20%) in zinc bath and bath temperature (733 K), the corrosion rate of mini-spangle GI sheet can be controlled to a level of 5.5 mpy.

Shukla, S. K.; Saha, B. B.; Triathi, B. D.; Avtar, Ram

2010-07-01

397

Optimising FSW process parameters to minimise defects and maximise fatigue life in 5083-H321 aluminium alloy  

Microsoft Academic Search

This paper presents a systematic approach to optimising FSW process parameters (tool rotational speed and feed rate) through consideration of frictional power input. Frictional power governs the tensile strength and the fatigue life in this 5083-H321 alloy through its effect on plastic flow processes in the thermo-mechanically affected zone (TMAZ) of the weld. Although, a close relationship therefore exists between

H. Lombard; D. G. Hattingh; A. Steuwer; M. N. James

2008-01-01

398

Investigation of Optimum Process Parameters on the Sheet Hydroforming of Titanium \\/ Aluminum Clad Metal for Battery Housing  

Microsoft Academic Search

This research presents an optimization implement to improve the clad metal formability and design cycle efficiency in sheet hydroforming process (SHF). An integration of finite element FE code (ABAQUS) and optimization code (SmartDO) has been presented for SHF with the consideration of response smoothing technology which can solve the optimum process parameters and avoid the local minimum by surmounting the

Huang-Chi Tseng; Zong-Chun Wu; Chinghua Hung; Ming-Hu Lee; Chin-Chuan Huang

399

The use of artificial intelligence technique for the optimisation of process parameters used in the continuous casting of steel  

Microsoft Academic Search

The productivity and quality of a continuous caster depend mainly on process parameters, i.e. casting speed, casting temperature, steel composition and cleanliness of the melt, water flow rates in the different cooling zones, etc. This work presents the development of an algorithm, which incorporates heuristic search techniques for direct application in metallurgical industries, particularly those using continuous casting process for

Carlos A. Santos; Jaime A. Spim Jr; Maria C. F. Ierardi; Amauri Garcia

2002-01-01

400

Automatic data processing based on the skewness statistic parameter for subsurface defect detection by active infrared thermography  

Microsoft Academic Search

Non-destructive testing (NDT) by active infrared thermography requires of data processing techniques in order to: i. improve the thermal contrast between defective and non-defective areas, and ii. reduce the large quantity of images recorded during the inspection without losing relevant information. In this paper, the use of the skewness statistic parameter is proposed for the automatic processing of thermographic sequences

F. J. Madruga; C. Ibarra-Castanedo; O. M. Conde; J. M. López-Higuera; X. Maldague

401

Impact of kinetic parameters on heat transfer modeling for a pultrusion process  

NASA Astrophysics Data System (ADS)

An examination is conducted of pultrusion heat model predictions for various parameters of resin chemical kinetics; these parameters' values affect model heat-transfer results and model predictions. Attention is given to the applicability of DSC kinetic parameters to resin cure modeling, by comparing the predicted product cure temperature profiles and resin degree-of-cure values with pultrusion experiment results obtained for both carbon and glass reinforcements, different pull speeds and fiber volumes, and various die temperature profiles.

Gorthala, R.; Roux, J. A.; Vaughan, J. G.; Donti, R. P.; Hassouneh, A.

402

Identification of forged Bank of England £20 banknotes using IR spectroscopy.  

PubMed

Bank of England notes of £20 denomination have been studied using infrared spectroscopy in order to generate a method to identify forged notes. An aim of this work was to develop a non-destructive method so that a small, compact Fourier transform infrared spectrometer (FT-IR) instrument could be used by bank workers, police departments or others such as shop assistants to identify forged notes in a non-lab setting. The ease of use of the instrument is the key to this method, as well as the relatively low cost. The presence of a peak at 1400 cm(-1) arising from ?asym (CO3(2-)) from the blank paper section of a forged note proved to be a successful indicator of the note's illegality for the notes that we studied. Moreover, differences between the spectra of forged and genuine £20 notes were observed in the ?(OH) (ca. 3500 cm(-1)), ?(C-H) (ca. 2900 cm(-1)) and ?(C=O) (ca. 1750 cm(-1)) regions of the IR spectrum recorded for the polymer film covering the holographic strip. In cases where these simple tests fail, we have shown how an infrared microscope can be used to further differentiate genuine and forged banknotes by producing infrared maps of selected areas of the note contrasting inks with background paper. PMID:24176248

Sonnex, Emily; Almond, Matthew J; Baum, John V; Bond, John W

2014-01-24

403

Microencapsulation by coacervation of poly(lactide-co-glycolide) IV. Effect of the processing parameters on coacervation and encapsulation  

Microsoft Academic Search

Attention has been paid to phase separation of poly (lactide-co-glycolide) solutions in CH2Cl2 induced by the addition of a silicone oil in order to promote protein microencapsulation. Since the process is very fast, the system is anytime out of equilibrium. The effect of the main processing parameters on the microencapsulation process has been analyzed and has highlighted that kinetics of

N. Nihant; C. Grandfils; R. Jérôme; P. Teyssié

1995-01-01

404

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

Microsoft Academic Search

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

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

405

Using radial basis function neural networks to recognize shifts in correlated manufacturing process parameters  

Microsoft Academic Search

Traditional statistical process control (SPC) techniues of control charting are not applicable in many process industries because data from these facilities are autocorrelated. Therefore the reduction in process variability obtained through the use of SPC techniques has not been realized in process industries. Techniques are needed to serve the same function as SPC control charts, that is to identify process

Deborah F. Cook; Chih-Chou Chiu

1998-01-01

406

A window-based image processing technique for quantitative and qualitative analysis of road traffic parameters  

Microsoft Academic Search

Traffic information is an important tool in the planning, maintenance, and control of any modern transport system. Of special interest to traffic engineers are parameters of traffic flow such as volume, speed, type of vehicle, queue parameters, traffic movements at junctions, etc. Various algorithms, mainly based on background differencing techniques, have been applied for this purpose. Since background-based algorithms are

M. Fathy; M. Y. Siyal

1998-01-01

407

Determination of a constant membrane structure parameter in forward osmosis processes  

Microsoft Academic Search

The membrane structure parameter (S) is an intrinsic membrane parameter used to determine the degree of internal concentration polarization (ICP) in the porous support structure of forward osmosis (FO) membranes, and is crucial in evaluations of FO membrane performance. Although S values only depend on membrane properties, and should be close to a constant value, experiments to determine the S

Ji Jung Lee; Sangho Lee; Joon Ha Kim

2011-01-01

408

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

Microsoft Academic Search

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

Shuokr Qarani Aziz; Hamidi Abdul Aziz; Mohd Suffian Yusoff

2011-01-01

409

Optimisation of processing and microstructural parameters of LSM cathodes to improve the electrochemical performance of anode-supported SOFCs  

Microsoft Academic Search

To improve the electrochemical performance of LSM-based anode-supported single cells, a systematic approach was taken for optimising processing and materials parameters. Four parameters were investigated in more detail: (1) the LSM\\/YSZ mass ratio of the cathode functional layer, (2) the grain size of LSM powder for the cathode current collector layer, (3) the thickness of the cathode functional layer and

V. A. C. Haanappel; J. Mertens; D. Rutenbeck; C. Tropartz; W. Herzhof; D. Sebold; F. Tietz

2005-01-01

410

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

411

Rule-based software tool to specify the manufacturing process parameters for a contoured EB-PVD coating  

NASA Astrophysics Data System (ADS)

A rule-based design software tool has been developed to specify the manufacturing process parameters to fabricate a contoured electron beam physical vapor deposited (EB-PVD) partially stabilized zirconia (PSZ) thermal barrier coating (TBC) on a curved surface. The expert data for this tool was developed from model predictions based on an experimentally verified, theoretical model of coating deposition rates as a function of position in the PVD vapor cloud (Knudsen cosine law). The predictive model was used for a wide variety of process parameters, including shadowing and non-uniform angular rotational velocity, to develop a database of contoured coating profiles (forward chaining). A coating profile matching routine was developed to identify the process parameters that yield a coating profile that matches the designers coating profile. The focus of this presentation will be on the software tool with emphasis on the expert database development and the coating thickness profile matching for a curved surface.

Weir, William C.; Sisson, Richard D.; Bose, Sudhangshu

2000-10-01

412

Modeling the x-ray process and x-ray flaw size parameter for POD studies  

NASA Astrophysics Data System (ADS)

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.

2014-03-01

413

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

414

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

415

Modeling of Texture Evolution during Hot Forging of Alpha/Beta Titanium Alloys  

NASA Astrophysics Data System (ADS)

Texture development during the subtransus hot forging of alpha/beta titanium alloys with an equiaxed-alpha microstructure was modeled using the Los Alamos polycrystalline plasticity (LApp) code and a {left< {111} rightrangle } pencil-glide polycrystalline plasticity code coupled with the finite-element-method (FEM) program DEFORM. The methodology treated the partitioning of the imposed strain between the alpha and beta phases, and thus enabled the prediction of the distinct deformation textures developed in the primary alpha and beta matrix during hot working. Two variant selection rules in conjunction with the beta deformation texture were also examined to establish a method for predicting the transformation texture of secondary alpha developed as a result of beta decomposition during cooldown following forging or heat treatment. The approach was validated via an industrial-scale trial comprising hot pancake forging of Ti-6Al-4V.

Glavicic, M. G.; Goetz, R. L.; Barker, D. R.; Shen, G.; Furrer, D.; Woodfield, A.; Semiatin, S. L.

2008-04-01

416

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

417

On the Estimation of Process Parameters in the Taguchi's Approach to the On-line Control Procedure for Attributes  

NASA Astrophysics Data System (ADS)

Under the model proposed by Nayebpour and Woodall [5] for Taguchi's on-line control procedure for attributes, estimators for the process parameter vector are derived both from the Classical (maximum likelihood) and Bayesian standpoints. The likelihood function is generated by the detection time of the first defective item under the control procedure. Under the Classical standpoint, a case of nonidentifiability is disclosed. Under the Bayesian standpoint, posterior probability distributions for the process parameters are determined by taking into account independent beta prior distributions.

Borges, Wagner S.; Esteves, Luis Gustavo; Wechsler, Sergio

2008-11-01

418

The Determination of Optimum Forging Conditions for the Production of High Strength-High Impact Toughness Automotive Parts  

Microsoft Academic Search

The influences of various reheating and forging temperatures as well as cooling rates on the microstructure and mechanical properties, particularly impact energy, during the forging of a Nb-V microalloyed steel to be used for automotive safety parts were investigated. Increasing the prior austenite grain size increased the volume percent of acicular ferrite and reduced pearlite content in the microstructure even

A. R. Khodabandeh; M. Jahazi; S. Yue; S. T. Aghdashi

2006-01-01

419

A Method for Measuring the Hardness of the Surface Layer on Hot Forging Dies Using a Nanoindenter  

Microsoft Academic Search

The properties and characteristics of the surface layer of forging dies are critical for understanding and controlling wear. However, the surface layer is very thin, and appropriate property measurements are difficult to obtain. The objective of the present study is to determine if nanoindenter testing provides a reliable method, which could be used to measure the surface hardness in forging

P. Mencin; C. J. van Tyne; B. S. Levy

2009-01-01

420

Process Parameters on the Crystallization and Morphology of Hydroxyapatite Powders Prepared by a Hydrolysis Method  

NASA Astrophysics Data System (ADS)

The effects of process parameters on the crystallization and morphology of hydroxyapatite (Ca10(PO4)6(OH)2, HA) powders synthesized from dicalcium phosphate dihydrate (CaHPO4·2H2O, DCPD) using a hydrolysis method have been investigated. X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) were used to characterize the synthesized powders. When DCPD underwent hydrolysis in 2.5 NaOH solution (Na(aq)) at 303 K to 348 K (30 °C to 75 °C) for 1 hour, the XRD results revealed that HA was obtained for all the as-dried samples. The SEM morphology of the HA powders for DCPD hydrolysis produced at 348 K (75 °C) shows regular alignment and a short rod shape with a size of 200 nm in length and 50 nm in width. With DCPD hydrolysis in 2.5 M NaOH(aq) holding at 348 K (75 °C) for 1 to 24 hours, XRD results demonstrated that all samples were HA and no other phases could be detected. Moreover, the XRD results also show that all the as-dried powders still maintained the HA structure when DCPD underwent hydrolysis in 0.1 to 5 M NaOH(aq) at 348 K (75 °C) for 1 hour. Otherwise, the full transformation from HA to octa-calcium phosphate (OCP, Ca8H2(PO4)6·5H2O) occurred when hydrolysis happened in 10 M NaOH(aq). FT-IR spectra analysis revealed that some carbonated HA (Ca10(PO4)6(CO3), CHA) had formed. The SEM morphology results show that the 60 to 65 nm width of the uniformly long rods with regular alignment formed in the HA powder aggregates when DCPD underwent hydrolysis in 2.5 M NaOH(aq) at 348 K (75 °C) for 1 hour.

Wang, Moo-Chin; Hon, Min-Hsiung; Chen, Hui-Ting; Yen, Feng-Lin; Hung, I.-Ming; Ko, Horng-Huey; Shih, Wei-Jen

2013-07-01

421

Analysis of process parameters in the laser deposition of YBa2Cu3O7 superconducting films by using SVR  

NASA Astrophysics Data System (ADS)

There are several process parameters in the growth of YBa2Cu3O7 superconducting films by using pulsed laser deposition (PLD). The relationship between the response and process parameters is highly nonlinear and quite complicated. It is very valuable to quantitatively estimate the response under different deposition parameters. In this study, according to an experimental data set on the superconducting transition temperature (Tc) and relative resistance ratio (rR) of 17 samples of YBa2Cu3O7 films deposited under various parameters, the support vector regression (SVR) combined with particle swarm optimization (PSO), was proposed to predict the Tc and rR for YBa2Cu3O7 films. The prediction performance of SVR was compared with that of multiple regression analysis (MRA) models. The results strongly support that the generalization ability of SVR model consistently surpasses that of MRA via leave-one-out cross validation (LOOCV). The mean absolute percentage errors for Tc and rR are 0.37% and 1.51% respectively via LOOCV test of SVR. Sensitivity analysis discovered the most sensitive parameters affecting the Tc and rR. This study suggests that the established SVR model can be used to accurately foresee the Tc and rR. And it can be used to optimizing the deposition parameters in the development of YBa2Cu3O7 films via PLD.

Cai, C. Z.; Xiao, T. T.; Tang, J. L.; Huang, S. J.

2013-10-01

422

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

423

Effect of Process Parameters, Casting Thickness, and Alloys on the Interfacial Heat-Transfer Coefficient in the High-Pressure Die-Casting Process  

Microsoft Academic Search

The heat transfer at the metal-die interface is believed to have great influence on the solidification process and cast structure\\u000a of the high-pressure die-casting (HPDC) process. The present article focused on the effects of process parameters, casting\\u000a thickness, and alloys on the metal-die interfacial heat-transfer coefficient (IHTC) in the HPDC process. Experiment was carried\\u000a out on a cold-chamber die-casting machine

Zhi-Peng Guo; Shou-Mei Xiong; Bai-Cheng Liu; Mei Li; John Allison

2008-01-01

424

Biodegradation Technology for VOC Removal from Airstreams. Phase 2. Determination of Process Design Parameters and Constraints.  

National Technical Information Service (NTIS)

The purpose of Phase II was to optimize the operation of the biofilter, by obtaining and using information on several process variables. Batch experiments were conducted to determine the fate of target compounds and the rates of various removal processes....

S. J. Ergas K. A. Kinney E. Morgenroth Y. Davidova K. M. Scow D. P. Y. Chang E. D. Schroeder

1995-01-01

425

Effect of process parameters on porosity distributions in high-pressure die-cast AM50 Mg-alloy  

Microsoft Academic Search

High-pressure die-casting is the preferred manufacturing process for cast Mg-alloy components used for numerous applications. High-pressure die-cast components usually contain micro-porosity that adversely affects their mechanical properties. In this contribution, the effects of three important process parameters, gate velocity, intensification pressure, and melt temperature on the micro-porosity distributions in high-pressure die-cast AM50 Mg-alloy are quantitatively characterized. The amounts of total

S. G. Lee; A. M. Gokhale; G. R. Patel; M. Evans

2006-01-01

426

Influence of processing parameters on particulate dispersion in direct laser sintered WC–Co p\\/Cu MMCs  

Microsoft Academic Search

Homogenizing the particulate dispersion in the matrix is an important consideration in obtaining high-quality particulate reinforced metal matrix composites (MMCs) using direct metal laser sintering (DMLS). In this paper, the effects of processing parameters in terms of laser power, scan speed, and powder layer thickness on the particulate dispersion in the DMLS-processed submicron WC–Cop\\/Cu1All the subscript “p” indicates powder form.1

Dongdong Gu; Yifu Shen; Jun Xiao

2008-01-01

427

The development of multi-response experimental designs for process parameter optimization  

Microsoft Academic Search

Purpose – The selection of the optimal process target for a manufacturing process is critically important as it directly affects the defect rate, rejection and rework costs, and the loss to customers. A recent review of process target literature suggests that future work should incorporate models using multiple quality characteristics. Thus, the purpose of this paper is to create a

Paul L. Goethals; Byung Rae Cho

2011-01-01

428

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

Microsoft Academic Search

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

Changyu Shen; Lixia Wang; Qian Li

2007-01-01

429

Effect of CO 2 laser cutting process parameters on edge quality and operating cost of AISI316L  

NASA Astrophysics Data System (ADS)

Laser cutting is a popular manufacturing process utilized to cut various types of materials economically. The width of laser cut or kerf, quality of the cut edges and the operating cost are affected by laser power, cutting speed, assist gas pressure, nozzle diameter and focus point position as well as the work-piece material. In this paper CO 2 laser cutting of stainless steel of medical grade AISI316L has been investigated. Design of experiment (DOE) was implemented by applying Box-Behnken design to develop the experiment lay-out. The aim of this work is to relate the cutting edge quality parameters namely: upper kerf, lower kerf, the ratio between them, cut section roughness and operating cost to the process parameters mentioned above. Then, an overall optimization routine was applied to find out the optimal cutting setting that would enhance the quality or minimize the operating cost. Mathematical models were developed to determine the relationship between the process parameters and the edge quality features. Also, process parameters effects on the quality features have been defined. Finally, the optimal laser cutting conditions have been found at which the highest quality or minimum cost can be achieved.

Eltawahni, H. A.; Hagino, M.; Benyounis, K. Y.; Inoue, T.; Olabi, A. G.

2012-06-01

430

Rule-based software tool to specify the manufacturing process parameters for a contoured EB-PVD coating  

Microsoft Academic Search

A rule-based design software tool has been developed to specify the manufacturing process parameters to fabricate a contoured electron beam physical vapor deposited (EB-PVD) partially stabilized zirconia (PSZ) thermal barrier coating (TBC) on a curved surface. The expert data for this tool was developed from model predictions based on an experimentally verified, theoretical model of coating deposition rates as a

William C. Weir; Richard D. Sisson; Sudhangshu Bose

2000-01-01

431

REMOVAL OF METHYL ORANGE AND METHYLENE BLUE DYE FROM WATER USING COLLOIDAL GAS APHRON—EFFECT OF PROCESSES PARAMETERS  

Microsoft Academic Search

Colloidal gas aphron (CGA) was used in a flotation column to remove methyl orange and methylene blue dye from water. The effect of process parameters, i.e., surfactant type and concentration, CGA flow rate, CGA diameter and gas holdup, pH, residence time, and salt concentration, were studied through measurements of percent dye removal. The overall percent removal of methyl orange and

S. Basu; P. R. Malpani

2001-01-01

432

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

433

Modeling the effects of cutting parameters in MQL-employed finish hard-milling process using D-optimal method  

Microsoft Academic Search

In any finish milling process the minimization of surface roughness is the prime objective, and if the workpiece belongs to the category of ultra-hard steels then the objective of maximizing tool life also gains considerable importance. In this research work, the effects of four parameters, namely, hardened steel's microstructure, workpiece inclination angle, cutting speed, and radial depth of cut were

Asif Iqbal; He Ning; Iqbal Khan; Li Liang; Naeem Ullah Dar

2008-01-01

434

Effect of process parameters on material removal rate in chemical mechanical polishing of Si(1 0 0)  

Microsoft Academic Search

The effect of changing process parameters on the material removal rate in chemical mechanical polishing (CMP) of Si(100) is examined. A bench-top machine and silica based slurries were used. The removal rate increases sublinearly with the applied pressure, plate speed, and slurry silica concentration. The removal rate increases in the beginning for new stock removal pads. This is in contrast

Markus Forsberg

2005-01-01

435

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

Microsoft Academic Search

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

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

2009-01-01

436

Influence of process parameters on SAC305 lead-free solder powder produced by centrifugal atomization  

Microsoft Academic Search

In the present work, a centrifugal atomizer was constructed in order to study the effects of operating parameters: rotating speed, melt feed rate, shape and size of atomizer, and oxygen content in the atomizer chamber, on the characters of SAC305 powder. It was evidenced from the experimental results that the median size of the atomized powders became smaller with increasing

Thawatchai Plookphol; Sirikul Wisutmethangoon; Sarawut Gonsrang

2011-01-01

437

Tests for Parameter Instability in Regressions with 1(1) Processes  

Microsoft Academic Search

This article derives the large-sample distributions of Lagrange multiplier (LM) tests for parameter instability against several alternatives of interest in the context of cointegrated regression models. The fully modified estimator of Phillips and Hansen is extended to cover general models with stochastic and deterministic trends. The test statistics considered include the SupF test of Quandt, as well as the LM

Bruce E. Hansen

1992-01-01

438

Effects of reaction parameters on boron carbide powder production by the carbothermic process  

Microsoft Academic Search

Experiments were carried out to determine suitable reaction parameters for carbothermic production of boron carbide from relatively fine reactants and relatively low temperatures, compared with traditional production in an Acheson furnace or in an electric arc furnace. Effects of carbon type and particle size, boron oxide particle size, boron oxide-to-carbon ratio, and temperature were determined.

D. L. Belitskus; R. J. Campbell; S. Y. Tzeng

1991-01-01

439

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

Microsoft Academic Search

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

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

1979-01-01

440

Physiological Parameters Measurement Based on Wheelchair Embedded Sensors and Advanced Signal Processing  

Microsoft Academic Search

This paper presents a multisensing system with wireless communication capabilities embedded on a smart wheelchair that can measure physiological parameters such as heart rate and respiratory rate in an unobtrusive way. Ballistocardiography (BCG) sensors and a three-axis inertial microelectromechanical system accelerometer are embedded on the seat or in the backrest of the wheelchair and the acquired data are transmitted by

Octavian A. Postolache; P. M. B. Silva Girao; Joaquim Mendes; Eduardo C. Pinheiro; Gabriela Postolache

2010-01-01

441

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

SciTech Connect

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

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

2007-07-01

442

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

443

Maize-Based Gluten-Free Bread: Influence of Processing Parameters on Sensory and Instrumental Quality  

Microsoft Academic Search

The performance of maize bread with spongy texture is still a technological challenge due to the absence of a natural network\\u000a required for holding the carbon dioxide released during the fermentation process. The objective of this research was to investigate\\u000a the influence of different maize varieties (regional and hybrid), milling process (electric and water mill), formulation and\\u000a processing variables on

Carla Brites; Maria João Trigo; Carla Santos; Concha Collar; Cristina M. Rosell

2010-01-01

444

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

445

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

446

Comparison of Mechanical Properties of 105mm M68 Gun Tube Forgings.  

National Technical Information Service (NTIS)

105mm M68 gun tube forgings are supplied at present by two vendors and the Watervliet Arsenal rotary system. A study was initiated to compare mechanical properties of the most recent vendor-supplied tubes with those supplied by them in the past. The vendo...

H. J. Powis

1980-01-01

447

Fuel-Efficient Forge Furnaces: Buyer incentives ease introduction and highlight benefits.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. A program of the accelerated introduction of high-performance forge furnaces has demonstrated that huge amounts of fuel can be saved--as much as 65 percent of the fu...

1983-01-01

448

iPads as Placed Resources: Forging Community in Online and Off line Spaces  

ERIC Educational Resources Information Center

The article focuses on the notion of tablet technologies as placed resources (Prinsloo, 2005; Prinsloo & Rowsell, 2012) by exploring how an international research project in Australia, Canada, and the United States forged community through online spaces. There is a tendency in media and in literature to romanticize technologies like iPads as a…

Rowsell, Jennifer; Saudelli, Mary Gene; Scott, Ruth Mcquirter; Bishop, Andrea

2013-01-01

449

Metallurgical Observations of a French A508 Class 3 Forging with Respect to Transition Toughness Behaviour.  

National Technical Information Service (NTIS)

A detailed chemical, microstructural and fractographic examination has been conducted on three large fracture toughness specimens chosen to represent the bounds of toughness at 5 C observed in a thick-section A508 Class 3 steel forging. Bulk and local che...

S. G. Druce J. M. Titchmarsh G. Jordan A. James

1985-01-01

450

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

451

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 with three groups of 8.9 cm pitch diameter spur gears made of vacuum-induction melted (VIM), vacuum-arc remelted (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. However, 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.; Zaretsky, E. V.; Bamberger, E. N.

1975-01-01

452

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.