Sample records for forging process parameters

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

    Microsoft Academic Search

    Nuri Akgerman; David J. Kasik

    1974-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    Maarefdoust, M.; Kadkhodayan, M.

    2010-06-01

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

  3. Precision forging processes for high-duty automotive components

    Microsoft Academic Search

    B.-A. Behrens; E. Doege; S. Reinsch; K. Telkamp; H. Daehndel; A. Specker

    2007-01-01

    Precision forging is defined as a flashless near net-shape forging operation which generates high quality parts concerning surface quality and dimensional accuracy. In the past, precision forging processes have been industrially established for axis-symmetric parts, e.g. gearwheels and steering pinions. Further development of the technology to more complex parts, e.g. helical gears, connecting rods and crankshafts is expected to lead

  4. Ductile fracture prediction in cold forging process chains

    Microsoft Academic Search

    P. F. Bariani; S. Bruschi; A. Ghiotti; M. Simionato

    2011-01-01

    The paper presents a new approach for the prediction of ductile fracture occurrence in multi-stage cold forging process chains. The approach combines the fracture criterion proposed by Xue and Wierzbicky with a linear damage accumulation law. Thanks to this feature, the approach is capable of predicting both the location where the failure events occur under the action of external loading

  5. Experimental study on process of precision forging of an aluminium-alloy rotor

    Microsoft Academic Search

    Debin Shan; Fang Liu; Wenchen Xu; Yan Lu

    2005-01-01

    This paper describes the process of precision forging of an aluminium-alloy rotor with 23 radial twist blades. Fully-enclosed die forging with isothermal condition was carried out to form the complexity shape rotor. A combined female die was designed to solve the die releasing. Several forming schemes were employed to reduce the forging pressure or to improve the die fill in

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

    NASA Astrophysics Data System (ADS)

    Pepelnjak, Tomaž; Kuzman, Karl; Kokol, Anton

    2011-05-01

    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.

  7. Material Behavior Based Hybrid Process for Sheet Draw-Forging Thin Walled Magnesium Alloys

    SciTech Connect

    Sheng, Z.Q.; Shivpuri, R. [Industrial, Welding and System Engineering at the Ohio State University, Columbus, Oh, 43210 (United States)

    2005-08-05

    Magnesium alloys are conventionally formed at the elevated temperatures. The thermally improved formability is sensitive to the temperature and strain rate. Due to limitations in forming speeds, tooling strength and narrow processing windows, complex thin walled parts cannot be made by traditional warm drawing or hot forging processes. A hybrid process, which is based on the deformation mechanism of magnesium alloys at the elevated temperature, is proposed that combines warm drawing and hot forging modes to produce an aggressive geometry at acceptable forming speed. The process parameters, such as temperatures, forming speeds etc. are determined by the FEM modeling and simulation. Sensitivity analysis under the constraint of forming limits of Mg alloy sheet material and strength of tooling material is carried out. The proposed approach is demonstrated on a conical geometry with thin walls and with bottom features. Results show that designed geometry can be formed in about 8 seconds, this cannot be formed by conventional forging while around 1000s is required for warm drawing. This process is being further investigated through controlled experiments.

  8. Process Modelling of IN718 for Free Forging

    SciTech Connect

    Yoshida, Hiroaki; Hatta, Takeshi; Hironaka, Tomohisa; Isogawa, Sachihiro [Research and Development Lab., Daido Steel Co., Ltd., 2-30 Daido-cho, Minami-ku, Nagoya (Japan); Sekiguchi, Hideaki [Shibukawa Plant, Daido Steel Co., Ltd., 500 Ishihara, Shibukawa (Japan)

    2007-05-17

    Ni based alloy IN718 is important material used for engine shafts, turbine disks of gas turbine engines. The grain refining of the IN718 becomes important because of the improvement of reliability. We have developed newly advanced {delta} process to obtain the grain of less than 22.5 {mu} m (ASTM No.8.0) even after solution treatment. Furthermore we have developed the microstructural prediction system of IN718 for the process modelling. In this paper, the advanced {delta} process and it's process modelling in the turbine disk forging were reported. As the result, we could obtain successful fine microstructure less than 22.5 {mu} m after solution treatment in turbine disk.

  9. Intelligent and controlled cooling technology and equipment research using to bearing ring part forging grinding process

    Microsoft Academic Search

    Zailin Ge; Yulong Ge; Yang Nianshen; Wang Dongju

    2010-01-01

    Combinating with the phenomena of excessive carbide mesh, micro-cracks and etc. in bearing ring forging parts becaus of cooling technology backwardness, study of new smart and controlled cooling technology and equipment to achieve cooling process automation, intelligent production process quality control, process equipment to ensure their quality. Through enterprise trial production testing, forging microstructure refinement after the cooling part, mesh

  10. Hot Forging of a Cladded Component by Automated GMAW Process

    NASA Astrophysics Data System (ADS)

    Rafiq, Muhammad; Langlois, Laurent; Bigot, Régis

    2011-01-01

    Weld cladding is employed to improve the service life of engineering components by increasing corrosion and wear resistance and reducing the cost. The acceptable multi-bead cladding layer depends on single bead geometry. Hence, in first step, the relationship between input process parameters and the single bead geometry is studied and in second step a comprehensive study on multi bead clad layer deposition is carried out. This paper highlights an experimental study carried out to get single layer cladding deposited by automated Gas Metal Arc Welding (GMAW) process and to find the possibility of hot forming of the cladded work piece to get the final hot formed improved structure. GMAW is an arc welding process that uses an arc between a consumable electrode and the welding pool with an external shielding gas and the cladding is done by alongside deposition of weld beads. The experiments for single bead were conducted by varying the three main process parameters wire feed rate, arc voltage and welding speed while keeping other parameters like nozzle to work distance, shielding gas and its flow rate and torch angle constant. The effect of bead spacing and torch orientation on the cladding quality of single layer from the results of single bead deposition was studied. Effect of the dilution rate and nominal energy on the cladded layer hot bending quality was also performed at different temperatures.

  11. Semisolid die forging process, microstructures and properties of AZ31 magnesium alloy mobile telephone shells

    NASA Astrophysics Data System (ADS)

    Guan, Ren-Guo; Chen, Li-Qing; Cao, Fu-Rong; Zhao, Zhan-Yong; Ren, Yong

    2011-12-01

    A semisolid slurry of AZ31 magnesium alloy was prepared by vibrating wavelike sloping plate process, and the semisolid die forging process, microstructures, and properties of the magnesium alloy mobile telephone shell were investigated. The semisolid forging process was performed on a YA32-315 four-column universal hydraulic press. The microstructures were observed by optical microscopy, the hardness was analyzed with a model 450SVD Vickers hardometer, the mechanical properties was measured with a CMT5105 tensile test machine, and the fractograph of elongated specimens was observed by scanning electron microscopy (SEM). The results reveal that with the increase of die forging force, the microstructures of the product become fine and dense. A lower preheating temperature and a longer dwell time are favorable to the formation of fine and dense microstructures. The optimum process conditions of preparing mobile telephone shells with excellent surface quality and microstructures are a die forging force of 2000 kN, a die preheating temperature of 250°C, and a dwell time of 240 s. After solution treatment at 430°C and aging at 220°C for 8 h, the Vickers hardness is 61.7 and the ultimate tensile strength of the product is 193 MPa. Tensile fractographs show the mixing mechanisms of quasi-cleavage fracture and ductile fracture.

  12. Thermo-mechanically coupled FE analysis and sensitivity study of simultaneous hot\\/cold forging process with local inductive heating and cooling

    Microsoft Academic Search

    Anton Matzenmiller; Christoph Bröcker

    The numerical investigation of the production of a stub shaft is presented, where the highly innovative metal forming technology\\u000a of the simultaneous hot and cold forging is applied in combination with a hardening process performed directly in the closed\\u000a forging dies after the forging step similar to press hardening of sheet metal. This complex forging process is completely\\u000a analysed by

  13. Manufacturing of Precision Forgings by Radial Forging

    SciTech Connect

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

    2011-01-17

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

  14. Computer-assisted Rheo-forging Processing of A356 Aluminum Alloys

    SciTech Connect

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

    2010-06-15

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

  15. Precision forging of spur gears with inside relief

    Microsoft Academic Search

    J. C Choi; Y Choi

    1999-01-01

    Conventional closed-die forgings as applied to the forging of spur gears require high forging pressure. In this paper, a precision forging technology has been developed for the forging of spur gears with alloy steel (SCM415). The technology developed includes two steps in the forging process. Well-shaped products are forged successfully using a lower forging pressure than that of conventional forging.

  16. 3D FEM simulation of the multi-stage forging process of a gas turbine compressor blade

    Microsoft Academic Search

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

    2008-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    1999-04-01

    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 2.3×1019n/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.

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

    SciTech Connect

    Kerry Barnett

    2003-03-01

    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

  19. Processing and development of aluminum-silicon powder metallurgy alloys for hot forging technologies

    NASA Astrophysics Data System (ADS)

    Mosher, Winston G. E.

    The growing field of aluminum powder metallurgy (PM) brings promise to an economical and environmental demand for the production of high strength, light weight aluminum engine components. To tackle the limited selection of readily available light alloy blends, an experimental hypoeutectic AlSi alloy was chosen for study. The optimal processing route for this alloy was determined and the mechanical properties were examined. In an effort to further enhance the mechanical properties of the alloys, post sinter forging was investigated. This body of work consists of an introduction to relevant topics in PM, aluminum alloys, and forging followed by three sections of results and discussion. Each represents an accepted or submitted Journal Manuscript intended for journal publication. These sections deliver detailed experimental procedures, results and discussion for the development of the experimental PM alloy Al-65i, a comparison of hot deformation behaviours of Al-65i and Alumix-231 Al5i PM alloys, and their mechanical properties observed upon hot densification. A final section was added to summarize the important findings from each experiment. In the development of Al-65i, the alloy was able to achieve a high sintered density approaching 98%, and a yield strength of 232 MPa in the T6 condition. Upon hot upset forging, the experimental alloy achieved an average density of 99.6% (+/- 0.2%) while the commercial alloy (Alumix-231) achieved 98.3% (+/- 0.6%) of its theoretical density. It was found that the experimentally obtained peak flow stresses for each material studied could be very closely approximated using the semi-empirical Zener-Hollomon models. Upon hot densification it was found that all the mechanical properties of the Al-65i alloy were significantly enhanced. However, due to the fracturing of 5i particles during deformation, Alumix-231 experienced a reduction in density and UT5, while making improvements in ductility.

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

    NASA Astrophysics Data System (ADS)

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

    2007-04-01

    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.

  1. Industrial Process Design for Manufacturing Inconel 718 Extremely Large Forged Rings

    NASA Astrophysics Data System (ADS)

    Ambielli, John F.

    2011-12-01

    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).

  2. Processing and properties of superclean ASTM A508 Cl. 4 forgings

    SciTech Connect

    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

    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.

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

    NASA Astrophysics Data System (ADS)

    Chi, Zhang; Bo, Xu

    2005-12-01

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

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

    PubMed Central

    Karthigeyan, R.; Ranganath, G.

    2013-01-01

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

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

    PubMed

    Karthigeyan, R; Ranganath, G

    2013-01-01

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

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

    E-print Network

    Desadier, Christopher Earl

    1987-01-01

    the determination of the J-integral at the initiation of crack growth. The advantage of this method is that accurate assessments of Table 5. Standard Composition of ASTM A 487 4Q and Compositions of Cast hlaterials Tested A487-4Q Weight C Mn P 8 Si Ni Cr... as to style and content by: W. L. Bradl (Chairman of Co ittee) ornwe (Member) D. N. Li tie (Member) C. F. ettl oroug (Head of Department) May 1987 ABSTRACT The Effect of processing Upon the Fracture Behavior of Cast and Forged Low Alloy Steel...

  7. Process Damping Parameters

    NASA Astrophysics Data System (ADS)

    Turner, Sam

    2011-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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.

  9. On Extrusion Forging and Extrusion Rolling of Thin Metal Sheets 

    E-print Network

    Feng, Zhujian

    2013-01-10

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

  10. Validation via FEM and plasticine modeling of upper bound criteria of a process-induced side-surface defect in forgings

    Microsoft Academic Search

    Y. H Moon; C. J Van Tyne

    2000-01-01

    Finite element analysis and plasticine modeling has been performed for an axisymmetric forging with a double ram action to validate the results of upper bound analysis which provided the geometric and processing conditions that can be used to avoid the development of unacceptable side-surface cracks. The finite element analysis, by using NIKE2D, an implicit finite deformation FEM program, has provided

  11. Effects of manipulator compliant movements on the quality of free forgings based on FEM simulation

    Microsoft Academic Search

    Xiaoming He

    In heavy forging, a manipulator is indispensable to help the precision of the forging process. The manipulator holds forging\\u000a workpiece during the forming process, but whether manipulator compliant movements have effects on forging quality of workpiece\\u000a is still unknown. A method to evaluate the effects of manipulator compliant movements on the forging quality qualitatively\\u000a is presented in this paper. Forging

  12. High-energy rate forgings of wedges :

    SciTech Connect

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

    2014-05-01

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

  13. A comparison of the properties of SPD-processed AA6061 by equal-channel angular pressing, multi-axial compressions\\/forgings and accumulative roll bonding

    Microsoft Academic Search

    Balakrishna Cherukuri; Teodora S. Nedkova; Raghavan Srinivasan

    2005-01-01

    Commercially available AA-6061 in the annealed condition was subject to severe plastic deformation (SPD) processing by equal-channel angular pressing (ECAP), multi-axial compression\\/forgings (MAC\\/F) and accumulative roll bonding (ARB) at room temperature to approximately the same accumulated strain (?4). Micro-hardness testing showed that materials processed by ECAP, MAC\\/F and ARB followed the same trend. The tensile properties of MAC\\/F- and ARB-processed

  14. On Extrusion Forging and Extrusion Rolling of Thin Metal Sheets

    E-print Network

    Feng, Zhujian

    2013-01-10

    forming process that combines extrusion and forging into one operation. In extrusion forging, the pin-fin surface feature is created by compressing the work-piece using a punch with designed cavities. Experiments and numerical analysis were conducted...

  15. Simple three-dimensional laser radar measuring method and model reconstruction for hot heavy forgings

    NASA Astrophysics Data System (ADS)

    Du, Zhengchun; Du, Yueyang

    2012-02-01

    Dimensional measurement of hot heavy forgings is desirable to permit real-time process control, but usually it is inconvenient because of the difficulty in working with very hot workpieces. We present a new three dimensional (3D) measuring approach based on a two-dimensional laser range sensor (TLRS). First, the measurement system is obtained by assembling a TLRS, an axis of rotation, and a servo motor, which rotates the scan plane of the laser ranger sensor and lets the TLRS scan forgings in different planes. Therefore, the coordinates of forging surface points can be obtained in a sensor coordinate system (SCS). According to the transformation matrix between the SCS and measurement coordinate system (MCS), coordinates of points in different SCSs can be transferred into one fixed MCS. Hence the actual 3D models of hot heavy forgings can be reconstructed by using a triangulated irregular network and be optimized by employing improved Delaunay rules. Different parameters of forgings, such as lengths and diameters, can be measured based on the 3D model. The new method is verified by experiments in both the laboratory and the forging workshop. The experimental results indicate that it is much more practical and convenient for the real-time, onsite measurement of hot heavy forgings.

  16. Forging of Advanced Disk Alloy LSHR

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Gayda, John; Falsey, John

    2005-01-01

    The powder metallurgy disk alloy LSHR was designed with a relatively low gamma precipitate solvus temperature and high refractory element content to allow versatile heat treatment processing combined with high tensile, creep and fatigue properties. Grain size can be chiefly controlled through proper selection of solution heat treatment temperatures relative to the gamma precipitate solvus temperature. However, forging process conditions can also significantly influence solution heat treatment-grain size response. Therefore, it is necessary to understand the relationships between forging process conditions and the eventual grain size of solution heat treated material. A series of forging experiments were performed with subsequent subsolvus and supersolvus heat treatments, in search of suitable forging conditions for producing uniform fine grain and coarse grain microstructures. Subsolvus, supersolvus, and combined subsolvus plus supersolvus heat treatments were then applied. Forging and subsequent heat treatment conditions were identified allowing uniform fine and coarse grain microstructures.

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

    SciTech Connect

    Huang Shiquan; Yi Youping; Zhang Yuxun [School of Mechanical and Electrical Engineering, Central South University, Changsha 410083 (China)

    2010-06-15

    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.

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

    SciTech Connect

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

    2007-04-07

    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.

  19. Forging Long Shafts On Disks

    NASA Technical Reports Server (NTRS)

    Tilghman, Chris; Askey, William; Hopkins, Steven

    1989-01-01

    Isothermal-forging apparatus produces long shafts integral with disks. Equipment based on modification of conventional isothermal-forging equipment, required stroke cut by more than half. Enables forging of shafts as long as 48 in. (122 cm) on typical modified conventional forging press, otherwise limited to making shafts no longer than 18 in. (46cm). Removable punch, in which forged material cools after plastic deformation, essential novel feature of forging apparatus. Technology used to improve such products as components of gas turbines and turbopumps and of other shaft/disk parts for powerplants, drive trains, or static structures.

  20. A study on the forging of external spur gears: upper-bound analyses and experiments

    Microsoft Academic Search

    J. C Choi; Y Choi

    1998-01-01

    In this study, the forging processes of spur gears have been investigated. The forging processes of spur gears have been classified into two types of operations, guiding one and clamping one in this investigation. Two types of forging have been analyzed by using upper bound method. The relative average punch pressure have been calculated and compared with each others for

  1. Partners: Forging Strong Relationships.

    ERIC Educational Resources Information Center

    Spears, Ellen, Ed.

    1999-01-01

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

  2. Flow simulation and solidification phenomena of AC4CH aluminum alloy in semi-solid forging process by explicit MPS method

    NASA Astrophysics Data System (ADS)

    Regmi, Amit; Shintaku, Hiroki; Sasaki, Tsutomu; Koshizuka, Seiichi

    2015-05-01

    Semi-solid forging (SSF) is a powerful manufacturing technology to fabricate near-net shaped products in automotive industries. During SSF process, the filling behavior and solidification process of AC4CH aluminum alloy is presented in this paper. The explicit MPS method program solving Navier-Stokes equation is coupled with heat transfer and solidification has been used to predict the filling pattern and temperature distribution of semi-solid material (SSM). The non-Newtonian rheological model was used as the constitutive equation of SSM. In this study, numerical analysis of SSF was carried out in box cavity with various flange thickness (4, 8, 12 and 16 mm) and corresponding experiments were undertaken for AC4CH aluminum alloy with solid fraction less than 0.5. The numerical results of SSM filling pattern and solidification phenomena in flange were validated with the experimental results. During solidification process, flow calculation was stopped and only thermal calculation was carried out. The shrinkage defect was well predicted near the lower mid area of the box cavity with flange thickness 16 mm.

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

    NASA Astrophysics Data System (ADS)

    Babu, Sailesh

    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.

  4. Forging of compressor blades: Temperature and ram velocity effects

    Microsoft Academic Search

    A. Saigal; K. Zhen; T. S. Chan

    1995-01-01

    Forging is one of the most widely used manufacturing process for making high-strength, structurally integrated, impact and creep-resistant Ti-6Al-4V compressor blades for jet engines. In addition, in modern metal forming technology, finite element analysis method and computer modeling are being extensively employed for initial evaluation and optimization of various processes, including forging. In this study, DEFORM, a rigid viscoplastic two-dimensional

  5. Forging an Identity: An Insider-outsider Study of Processes Involved in the Formation of Organizational Identity

    Microsoft Academic Search

    Dennis A. Gioia; Kristin N. Price; Aimee L. Hamilton; James B. Thomas

    2010-01-01

    We investigated the processes involved in forming an organizational identity, which we studied during the founding of a distinctive new college by using an interpretive, insider-outsider research approach. The emergent grounded theory model suggests that organizational identity formed via the interplay of eight notable processes, four of which occurred in more-or-less sequential, stage-like fashion —(1) articulating a vision, (2) experiencing

  6. Tool Path Design of Incremental Open-Die Disk Forging Using Physical Modeling

    NASA Astrophysics Data System (ADS)

    Lee, Sung-Uk; Yang, Dong-Yol

    A small-batch product of large-sized parts is usually manufactured using incremental open-die forging. In order to control the overall change in the shape of a part, it is essential to be able to predict the shape changes that occur during each step. This paper addresses shape changes of a material according to the forging path. Rapid prediction of metal flows for continuing incremental deformation using theoretical methods is difficult. Accordingly, instead of a theoretical approach, an experiment that tests the tendency of the metal flow for development of forming processes is required. For the sake of convenience, simulative experiments are carried out using plasticine at room temperature. In present study, the tool movement is dominant parameters to with respect to changing the shape of the workpiece.

  7. Finite Element Simulation of the Tool Steel Stress Response As Used In a Hot Forging

    NASA Astrophysics Data System (ADS)

    Hjertsén, David; Sjöström, Johnny; Bergström, Jens; Näsström, Mats

    2004-06-01

    Hot-work forging tools are subjected to severe and complex loading conditions (cyclic stress/strain conditions, varying strain rates, varying temperature, environmental damage), leading to short die life. There is also a temperature and time dependant material response to consider. Presently, hot-forging of a steel crankshaft is approached by a combined experimental and numerical simulation study of a hot-work tool steel. The forging conditions were investigated by thermal measurements and damage analysis. Laboratory testing by isothermal fatigue in the temperature range 200 - 600 °C was performed. An elasto-plastic kinematic and isotropic hardening model (according to Chaboche) was used to model the material behaviour where the material parameters were derived from the experimental part. Viscoplastic effects are not accounted for in the material model as they have minor influence on the stress-strain relation in the experimental setup. The model was implemented in a FEM program (MSC.Marc) using a semi-implicit time integration scheme according to Shih and Ortiz, and evaluated by modelling of the isothermal fatigue tests. The FE-results managed to describe the materials general behavior, the correlation between the experimental simulated values were however not satisfactory due to influence of factors in the parameter derivation. Important features of the material behaviour are the cyclic softening and its dependence of the temperature, and also the strain path history. The long-term goal is to fully analyze the hot-forging die in service by numerical simulation and to study the influence of manufacturing processes on die properties.

  8. Investigations on Forging Dies with Ceramic Inserts by means of Finite-Element-Analysis

    NASA Astrophysics Data System (ADS)

    Behrens, B.-A.; Schäfer, F.; Bistron, M.

    2007-05-01

    The tools in hot forging processes are exposed to high thermal and mechanical loadings. Tempering of the tool edge layer occurs as a result of thermal loadings. This leads to a gradual hardness loss of the tool material and increase of wear over forging cycles. Hence, the tool life in hot forging is mainly limited by wear. An extension of the die service life can be achieved by the use of ceramic inserts. The integration of ceramics into the die base plate made of hot-work steel is realised by active brazing, whereby it possible to apply ceramic in region with high wear. It has to be ensured in the design process of ceramic inserts for forging dies that no critical tensile stresses occur in the ceramics. A reliable design of the ceramic inserts is possible only through consideration of brazing and forming process. The development of a Finite-Element-model for the design of forging dies with ceramic inserts is the intention of the work presented in this paper. At first the forging process with a conventional die is analyzed concerning abrasive die wear to identify regions with high wear risk applying a modified Archard model. Based on the results of wear calculation, a forging die with ceramic inserts is investigated in terms of joint stresses at the end of the active brazing process. Subsequently, the forging process considering the residual stresses caused by joining is simulated in order to obtain the die stress in use.

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

    SciTech Connect

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

    1986-05-01

    Three advanced steel-melting processes - low-sulfur vacuum silicon deoxidation, electroslag remelting, and vacuum carbon deoxidation (VCD) - were applied to produce three CrMoV (ASTM A470, Class 8) steel forgings for steam turbine application. Ingots weighing about 100 t each were produced using these three processes, and rotors were forged with final weights of about 30 t each. Compared to the conventionally produced forgings, the advanced technology forgings show better tensile ductility and better uniformity along the radial and longitudinal directions. Charpy upper-shelf energy shows about 40% improvement, and no temper embrittlement was found using step-cooled and isothermal-aging treatments. Significant improvement in fracture toughness (K/sub IC/ and J/sub IC/) is realized for these forgings. Low-cycle fatigue life is better at high temperatures because of the absence of nonmetallic inclusions. Creep strength shows slight improvement. However, creep ductility is improved, probably because of low residual elements. The VCD forgings show excellent creep ductility, even with long lives. Both the toughness and creep properties are equal to or better than those of oil-quenched rotors produced by European practices. These improvements are attributed to cleaner steel, better control of ingot solidification, low residual elements (especially very low sulfur content), and the associated reduction of nonmetallic inclusions. These three rotors have been placed in service in three operating power plants in units rated at 520 MW each. Volume 1 of this report covers ingot and forging production, and volume 2 covers mechanical property evaluation.

  10. A study on the forging of spur gears

    Microsoft Academic Search

    J. C. Choi; Y. Choi; K. D. Hur; C. H. Kim

    1996-01-01

    In this paper, the forging of spur gears have been analysed by using the upper-bound method. The tooth profile of the gear consists of an involute curve and a circular arc shaped fillet. A kinematically admissible velocity field is newly proposed. Numerical calculations have been carried out to investigate the effects of various parameters, such as module, number of teeth,

  11. DESIGN AND MANUFACTURE OF STRAIGHT BEVEL GEAR FOR PRECISION FORGING DIE BY DIRECT MILLING

    Microsoft Academic Search

    K. Kawasaki; K. Shinma

    2008-01-01

    In the manufacture of straight bevel gears, a precision forging method has been mainly used in recent years and the precision forging die has been usually manufactured using electric discharge machining. However, it is difficult to content the high productivity and low manufacturing cost using electric discharge machining because the gears are produced through a process of several steps. In

  12. Critical process parameters for UCO kernel production

    SciTech Connect

    DeVelasco, R.I.

    1988-09-20

    UCO kernel fabrication was previously demonstrated at 2 kg per batch. The limiting factors were the size of the sintering furnace and the UCO drop columns. The former UCO drop columns also showed considerable variability in the quality of gelled microspheres. A larger-size sintering furnace and a set of drop columns with an improved design were installed in 1987. The new set of drop columns and sintering furnace, in conjunction with other modular-sized equipment, were designed to produce the reference batch size of 5.5 kg of UCO kernels containing 5 kg of heavy metal (HM). The new equipment was utilized in the manufacture of several 2 kg batches of UCO kernels and ran well. In the process development reported here, the batch size was scaled-up to 5.5 kg. While the equipment is performing as expected, some of the process parameters still need to be optimized. In the body of this document is a description of the process to make UCO kernels via Gel Supported Precipitation (GSP) technology and the critical parameters that were changed to scale-up the kernel batch size to 5.5 kg, while meeting product specifications.

  13. New Trends in Forging Technologies

    Microsoft Academic Search

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

    2011-01-01

    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

  14. Transatlantic Perspectives Forging Legitimizing Coalitions

    E-print Network

    Boyer, Edmond

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

  15. Development of high purity large forgings for nuclear power plants

    NASA Astrophysics Data System (ADS)

    Tanaka, Yasuhiko; Sato, Ikuo

    2011-10-01

    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.

  16. [Research on the inner wall condition monitoring method of ring forgings based on infrared spectra].

    PubMed

    Fu, Xian-bin; Liu, Bin; Wei, Bin; Zhang, Yu-cun; Liu, Zhao-lun

    2015-01-01

    In order to grasp the inner wall condition of ring forgings, an inner wall condition monitoring method based on infrared spectra for ring forgings is proposed in the present paper. Firstly, using infrared spectroscopy the forgings temperature measurement system was built based on the three-level FP-cavity LCTF. The two single radiation spectra from the forgings' surface were got using the three-level FP-cavity LCTF. And the temperature measuring of the surface forgings was achieved according to the infrared double-color temperature measuring principle. The measuring accuracy can be greatly improved by this temperature measurement method. Secondly, on the basis of the Laplace heat conduction differential equation the inner wall condition monitoring model was established by the method of separating variables. The inner wall condition monitoring of ring forgings was realized via combining the temperature data and the forgings own parameter information. Finally, this method is feasible according to the simulation experiment. The inner wall condition monitoring method can provide the theoretical basis for the normal operating of the ring forgings. PMID:25993823

  17. Nonstationary magnetotelluric data processing with instantaneous parameter

    NASA Astrophysics Data System (ADS)

    Neukirch, M.; Garcia, X.

    2014-03-01

    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.

  18. Industrial forging applications of shaping simulation using modeling clay

    NASA Astrophysics Data System (ADS)

    Ravassard, P.; Bournicon, C.

    1982-09-01

    The use of Plasticine and similar modeling materials to simulate forgings is advocated. It permits low cost studies of complex processes for manufacturing or training purposes without interfering with work schedules of real machines. Criteria for choosing a clay, construction of dies, equipment, and laboratory procedures are described.

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

    NASA Technical Reports Server (NTRS)

    Bamberger, E. N.

    1973-01-01

    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.

  20. Bounded-parameter Markov Decision Processes, June 16, 2000 1 Bounded-parameter Markov Decision Processes

    E-print Network

    Dean, Thomas

    @ecn.purdue.edu Email: {sml, tld}@cs.brown.edu Web: http://www.ece.purdue.edu/~givan Web: http://www.cs.brown.edu/~{sml, tld} Abstract In this paper, we introduce the notion of a bounded-parameter Markov decision process

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

    NASA Technical Reports Server (NTRS)

    Gayda, John (Technical Monitor); Lemsky, Joe

    2004-01-01

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

  2. Overview and Analysis of the Meltblown Process and Parameters

    Microsoft Academic Search

    Kathryn C. Dutton

    This paper is a comprehensive review of the meltblown process and parameters. The meltblown process is complex because of the many parameters and interrelationships between those parameters. Due to the competitiveness of the industry, process settings and polymers used are secretive, but there are several key researchers that have published studies on the interactions of meltblown variables. A majority of

  3. Effect of processing parameters on autoclaved PMR polyimide composites

    NASA Technical Reports Server (NTRS)

    Vannucci, R. D.

    1977-01-01

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

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

    SciTech Connect

    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

    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.

  5. Evaluation of Control Parameters for the Activated Sludge Process

    ERIC Educational Resources Information Center

    Stall, T. Ray; Sherrard, Josephy H.

    1978-01-01

    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)

  6. Processing parameters affecting sorghum noodle qualities 

    E-print Network

    Kunetz, Christine Frances

    1997-01-01

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

  7. Research of knowledge-based hammer forging design support system

    Microsoft Academic Search

    Chen Xuewen; Zuo Siyu; Chen Jun; Ruan Xueyu

    2005-01-01

    Die design is experience-extensive in the field of plasticity engineering, in which knowledge and experience play a very important role in supporting the design process. In order to make good use of the accumulated engineering knowledge, the methodology of knowledge-based hammer forging design support is elaborated in detail, including: engineering knowledge representation, knowledge acquisition and knowledge-based design support techniques. Based

  8. Improvement of hot forging manufacturing with PVD and DUPLEX coatings

    Microsoft Academic Search

    Boris Navinšek; Peter Panjan; Frank Gorenjak

    2001-01-01

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

  9. Sensitivity of cloud condensation nuclei activation processes to kinetic parameters

    E-print Network

    Chuang, Patrick Y.

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

  10. Forging Industry Technical Conference, Cleveland, Ohio, 2002 FATIGUE PERFORMANCE EVALUATION OF FORGED VERSUS

    E-print Network

    Fatemi, Ali

    competitions to forged steel steering knuckle are cast iron and cast aluminum steering knuckles. The overall consideration in the design and performance evaluation of materials, components, and structures since about 90 properties of forgings and competitive products such as castings. Mechanical properties evaluated mainly

  11. Forging the Ideal Liberal LearningForging the Ideal Liberal Learning (Goals of Education)

    E-print Network

    Miyashita, Yasushi

    Active Learning of English for Science Students 3CWPCritical Writing Program 4 New Textbooks for Life1 Forging the Ideal Liberal LearningForging the Ideal Liberal Learning (Goals of Education the Ideal Liberal Learning 1 (Structuring of Knowledge) 2005 GFK lectures since 2005 #12;3 GFK

  12. Making randomised trials more efficient: report of the first meeting to discuss the Trial Forge platform.

    PubMed

    Treweek, Shaun; Altman, Doug G; Bower, Peter; Campbell, Marion; Chalmers, Iain; Cotton, Seonaidh; Craig, Peter; Crosby, David; Davidson, Peter; Devane, Declan; Duley, Lelia; Dunn, Janet; Elbourne, Diana; Farrell, Barbara; Gamble, Carrol; Gillies, Katie; Hood, Kerry; Lang, Trudie; Littleford, Roberta; Loudon, Kirsty; McDonald, Alison; McPherson, Gladys; Nelson, Annmarie; Norrie, John; Ramsay, Craig; Sandercock, Peter; Shanahan, Daniel R; Summerskill, William; Sydes, Matt; Williamson, Paula; Clarke, Mike

    2015-01-01

    Randomised trials are at the heart of evidence-based healthcare, but the methods and infrastructure for conducting these sometimes complex studies are largely evidence free. Trial Forge ( www.trialforge.org ) is an initiative that aims to increase the evidence base for trial decision making and, in doing so, to improve trial efficiency.This paper summarises a one-day workshop held in Edinburgh on 10 July 2014 to discuss Trial Forge and how to advance this initiative. We first outline the problem of inefficiency in randomised trials and go on to describe Trial Forge. We present participants' views on the processes in the life of a randomised trial that should be covered by Trial Forge.General support existed at the workshop for the Trial Forge approach to increase the evidence base for making randomised trial decisions and for improving trial efficiency. Agreed upon key processes included choosing the right research question; logistical planning for delivery, training of staff, recruitment, and retention; data management and dissemination; and close down. The process of linking to existing initiatives where possible was considered crucial. Trial Forge will not be a guideline or a checklist but a 'go to' website for research on randomised trials methods, with a linked programme of applied methodology research, coupled to an effective evidence-dissemination process. Moreover, it will support an informal network of interested trialists who meet virtually (online) and occasionally in person to build capacity and knowledge in the design and conduct of efficient randomised trials.Some of the resources invested in randomised trials are wasted because of limited evidence upon which to base many aspects of design, conduct, analysis, and reporting of clinical trials. Trial Forge will help to address this lack of evidence. PMID:26044814

  13. Effect of processing parameters on reaction bonding of silicon nitride

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    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.

  14. ODE parameter inference using adaptive gradient matching with Gaussian processes

    E-print Network

    Filippone, Maurizio

    predicted from the differen- tial equations, offer a computationally ap- pealing shortcut to the inferenceODE parameter inference using adaptive gradient matching with Gaussian processes F. Dondelinger M Parameter inference in mechanistic models based on systems of coupled differential equa- tions is a topical

  15. Continuous simulation of hypothetical physics processes with multiple free parameters

    E-print Network

    Jiahang Zhong; Run-Sheng Huang; Shih-Chang Lee

    2012-05-31

    We propose a new approach to simulate hypothetical physics processes which are defined by multiple free parameters. Compared to the conventional grid-scan approach, the new method can produce accurate estimations of the detector acceptance and signal event yields continuously over the parameter space with fewer simulation events. The performance of this method is illustrated with two realistic cases.

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

    Microsoft Academic Search

    C. R. Rekha; G. Vijayalakshmi

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

  17. Concurrent optimization of machining process parameters and tolerance allocation

    Microsoft Academic Search

    V. Janakiraman; R. Saravanan

    2010-01-01

    With the advent use of sophisticated and high-cost machines coupled with higher labor costs, concurrent optimization of machining\\u000a process parameters and tolerance allocation plays a vital role in producing the parts economically. In this paper, an effort\\u000a is made to concurrently optimize the manufacturing cost of piston and cylinder components by optimizing the operating parameters\\u000a of the machining processes. Design

  18. Estimation of Clustering Parameters Using Gaussian Process Regression

    PubMed Central

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

    2014-01-01

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

  19. Optimization of squeeze cast parameters of LM6 aluminium alloy for surface roughness using Taguchi method

    Microsoft Academic Search

    P. Vijian; V. P. Arunachalam

    2006-01-01

    The ability to produce near net shape components with good surface finish is made possible by means of squeeze casting, a hybrid metal forming process combining features of both casting and forging in a single operation. The primary objective of this paper is to analyze the influence of the process parameters on surface roughness in squeeze casting of LM6 aluminium

  20. Microstructure Evolution of Superalloy for Large Exhaust Valve during Hot Forging

    NASA Astrophysics Data System (ADS)

    Jeong, H. S.; Cho, J. R.; Park, H. C.

    2004-06-01

    The nickel-based alloy Nimonic 80A possesses strength, and corrosion, creep and oxidation resistance at high temperature. These products are used for aerospace, marine engineering and power generation, etc. The control of forging parameters such as strain, strain rate, temperature and holding time is important because the microstructure change in hot working affects the mechanical properties. It is necessary to understand the microstructure variation evolution. The microstructure change evolution occurs by recovery, recrystallization and grain growth phenomena. The dynamic recrystallization evolution has been studied in the temperature range 950-1250°C and strain rate range 0.05-5s-1 using hot compression tests. The metadynamic recrystallization and grain growth evolution has been studied in the temperature range 950-1250°C and strain rate range 0.05, 5s-1, holding time range 5, 10, 100, 600 sec using hot compression tests. Modeling equations are developed to represent the flow curve, recrystallized grain size, recrystallized fraction and grain growth phenomena by various tests. Parameters of modeling equation are expressed as a function of the Zener-Hollomon parameter. The modeling equation for grain growth is expressed as a function of initial grain size and holding time. The developed modeling equation was combined with thermo-viscoplastic finite element modeling to predict various microstructure change evolution during thermo mechanical processing. The predicted grain size in developed FE simulation results is compared with results obtained in various tests. In order to obtain a final microstructure and good mechanical properties in forging, the FEM would become a useful tool in the simulation of the microstructure development.

  1. Non-isothermal FEM analyses of large-strain back extrusion forging

    SciTech Connect

    Flower, E.C.; Hallquist, J.O.; Shapiro, A.B.

    1986-06-19

    Back extrusion forging is a complex metal forming operation dominated by large-strain, non-isothermal deformation. NIKE2D, a fully vectorized implicit finite-element program developed at Lawrence Livermore National Laboratory, was applied to a two-stage isothermal back extrusion forging process. Modeling of the forging process required special features in the FEM code such as friction and interactive rezoning that allows for remeshing of the distorted mesh while maintaining a complete history of all the state variables. To model conditions of the non-isothermal forging process required implementing TOPAZ2D, our LLNL-developed two-dimensional implicit finite element code for heat conduction analysis, as a subroutine into NIKE2D. The fully coupled version maintains all the original features of both codes and can account for the contribution of heat generation during plastic deformation. NIKE/TOPAZ-2D was applied to the piercing operation of the back extrusion forging process. The thermal deformation history of the die, punch, and workpiece and the effective plastic strains were calculated.

  2. Stainless-steel elbows formed by spin forging

    NASA Technical Reports Server (NTRS)

    1964-01-01

    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.

  3. Heat Recovery in the Forge Industry

    E-print Network

    Shingledecker, R. B.

    1982-01-01

    to the pounds of product heated will provide a measure of heating costs that include both delays and stand-by operation. i. Reduce scrap rate. Every forger is sensitive to the monetary loss when scrap forgings are produced. Too few companies, however..., consider the fuel cost of producing scrap. Energy is used to produce a given forging,. whether or not it is usable. If the item is not usable, a like amount of energy is required to reproduce it so as to meet the customer's ship schedule. Any forger...

  4. Effect of Parameters on Coating Density for Cold Spray Process

    Microsoft Academic Search

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

    2011-01-01

    In this research paper, Taguchi L18 orthogonal array has been employed for depositing electro-conductive coatings by varying various process and material parameters i.e., type of powder feeding arrangement, substrate material, stagnation gas temperature, stagnation gas pressure and stand-off distance. The response parameter of the low-pressure cold spray coatings produced is measured in terms of coating density. The analyses of the

  5. Effect of Parameters on Coating Density for Cold Spray Process

    Microsoft Academic Search

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

    2012-01-01

    In this research article, Taguchi L18 orthogonal array has been employed for depositing electro-conductive coatings by varying process and material parameters, i.e., type of powder feeding arrangement, substrate material, stagnation gas temperature, stagnation gas pressure, and standoff distance. The response parameter of the low-pressure cold spray coatings produced is measured in terms of coating density. The analyses of the raw

  6. 76 FR 50755 - Heavy Forged Hand Tools From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

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

  7. Sensitivity analysis for process parameters influencing weld quality in robotic GMA welding process

    Microsoft Academic Search

    I. S. Kim; Y. J. Jeong; I. J. Son; I. J. Kim; J. Y. Kim; I. K. Kim; Prasad K. D. V. Yaragada

    2003-01-01

    Generally, the quality of a weld joint is strongly influenced by process parameters during the welding process. In order to achieve high quality welds, mathematical models that can predict the bead geometry to accomplish the desired mechanical properties of the weldment should be developed. This paper focuses on development of mathematical models for the selection of process parameters and the

  8. A dimensionless parameter model for arc welding processes

    NASA Astrophysics Data System (ADS)

    Fuerschbach, P. W.

    A dimensionless parameter model previously developed for CO2 laser beam welding has been shown to be applicable to GTAW and PAW autogenous arc welding processes. The model facilitates estimates of weld size, power, and speed based on knowledge of the material's thermal properties. The dimensionless parameters can also be used to estimate the melting efficiency, which eases development of weld schedules with lower heat input to the weldment. The mathematical relationship between the dimensionless parameters in the model has been shown to be dependent on the heat flow geometry in the weldment.

  9. Microstructure prediction of Nimonic 80A for large exhaust valve during hot closed die forging

    Microsoft Academic Search

    H. S. Jeong; J. R. Cho; H. C. Park

    2005-01-01

    The nickel-based alloy Nimonic 80A possesses strength, and corrosion, creep and oxidation resistance at high temperature. These products are used for aerospace, marine engineering and power generation, etc. The control of forging parameters such as strain, strain rate, temperature and holding time is important because the microstructure change in hot working affects the mechanical properties. It is necessary to understand

  10. Microstructure Evolution of Superalloy for Large Exhaust Valve during Hot Forging

    Microsoft Academic Search

    H. S. Jeong; J. R. Cho; H. C. Park

    2004-01-01

    The nickel-based alloy Nimonic 80A possesses strength, and corrosion, creep and oxidation resistance at high temperature. These products are used for aerospace, marine engineering and power generation, etc. The control of forging parameters such as strain, strain rate, temperature and holding time is important because the microstructure change in hot working affects the mechanical properties. It is necessary to understand

  11. Assisted Defect Recognition for the Ultrasonic Multizone Inspection of Titanium Forgings

    Microsoft Academic Search

    A. F. Ferro; P. J. Howard

    2009-01-01

    Titanium aircraft engine disk forgings are imaged at all material depths using the ultrasonic testing (UT) process called multizone inspection. This process results in highly variable background noise from material microstructure. The intention is to ultimately accept or reject the part by examining for the presence of small anomalies in these images in terms of their signal to noise ratio

  12. ASSISTED DEFECT RECOGNITION FOR THE ULTRASONIC MULTIZONE INSPECTION OF TITANIUM FORGINGS

    Microsoft Academic Search

    A. F. Ferro; P. J. Howard

    2009-01-01

    Titanium aircraft engine disk forgings are imaged at all material depths using the ultrasonic testing (UT) process called multizone inspection. This process results in highly variable background noise from material microstructure. The intention is to ultimately accept or reject the part by examining for the presence of small anomalies in these images in terms of their signal to noise ratio

  13. 29 CFR 1910.218 - Forging machines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...The power to the press shall be locked out. (ii) The flywheel shall be at rest. (iii) The ram shall be blocked with...machine, the power to the upsetter shall be locked out, and the flywheel shall be at rest. (i) Other forging equipment...

  14. 29 CFR 1910.218 - Forging machines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...The power to the press shall be locked out. (ii) The flywheel shall be at rest. (iii) The ram shall be blocked with...machine, the power to the upsetter shall be locked out, and the flywheel shall be at rest. (i) Other forging equipment...

  15. 29 CFR 1910.218 - Forging machines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...The power to the press shall be locked out. (ii) The flywheel shall be at rest. (iii) The ram shall be blocked with...machine, the power to the upsetter shall be locked out, and the flywheel shall be at rest. (i) Other forging equipment...

  16. 29 CFR 1910.218 - Forging machines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...The power to the press shall be locked out. (ii) The flywheel shall be at rest. (iii) The ram shall be blocked with...machine, the power to the upsetter shall be locked out, and the flywheel shall be at rest. (i) Other forging equipment...

  17. 29 CFR 1910.218 - Forging machines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...The power to the press shall be locked out. (ii) The flywheel shall be at rest. (iii) The ram shall be blocked with...machine, the power to the upsetter shall be locked out, and the flywheel shall be at rest. (i) Other forging equipment...

  18. Forging Collaborative Partnerships: The Waterloo Neighborhood Project.

    ERIC Educational Resources Information Center

    Gruenewald, Anne

    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…

  19. Deep case gas carburizing—Optimization of process parameters

    Microsoft Academic Search

    Harry Walton

    1990-01-01

    Deep case gas carburizing being an energy intensive process requires that a specific case depth be obtained in a minimum of\\u000a time while still ensuring the metallurgical and dimensional integrity of the part. This may be achieved by first optimizing\\u000a the cycle parameters using computer simulation techniques. After refinement, such algorithm may be incorporated into a total\\u000a process control system.

  20. Spatial Estimation of Wafer Measurement Parameters Using Gaussian Process Models

    E-print Network

    Makris, Yiorgos

    Spatial Estimation of Wafer Measurement Parameters Using Gaussian Process Models Nathan Kupp, Ke) are collected to monitor the health-of-line and to make wafer scrap decisions preceding final test. These measurements are typically sampled spatially across the surface of the wafer from between-die scribe line sites

  1. Integrating MRSN ratio and ANP to optimize process parameter of multiple-response injection molding process

    Microsoft Academic Search

    Wei-Jaw Deng

    2008-01-01

    Multi-response signal to noise ratio (MRSN Ratio) technique is one of reformed Taguchi kind technique for using in multiple-quality response process parameter optimization. However, the assignment of each quality response weight in MRSN Ratio technique is a subjective or empirical process that may be unrealistic and possibly cause the misleading result of multiple-quality response process parameter optimization. Analytic Network Process

  2. Spray automated balancing of rotors - How process parameters influence performance

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  3. Effect of Process Parameters on Catalytic Incineration of Solvent Emissions

    PubMed Central

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

    2008-01-01

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

  4. An approach to simulate cold roll-forging of turbo-engine thin compressor blade

    Microsoft Academic Search

    M. Sedighi; M. Mahmoodi

    2009-01-01

    Purpose – Studying manufacturing process of compressor blade can reduce the production cost and time in aircraft turbo-engine industries. In the cold roll-forging of thin compressor blades, the elastic behavior of machine structure and rolls is considerable due to the higher volume of roll separating force. Owing to this kind of elastic deformation during rolling, the adjusted gap between the

  5. FEA Based Tool Life Quantity Estimation of Hot Forging Dies Under Cyclic ThermoMechanical Loads

    Microsoft Academic Search

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

    2011-01-01

    Hot forging dies are exposed during service to a combination of cyclic thermo-mechanical, tribological and chemical loads. Besides abrasive and adhesive wear on the die surface, fatigue crack initiation with subsequent fracture is one of the most frequent causes of failure. In order to extend the tool life, the finite element analysis (FEA) may serve as a means for process

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

    Microsoft Academic Search

    JONATHAN WILLIAMS; FARZIN MONTAZERSADGH; ALI FATEMI

    2007-01-01

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

  7. Diffusion parameters of indium for silicon process modeling

    NASA Astrophysics Data System (ADS)

    Kizilyalli, I. C.; Rich, T. L.; Stevie, F. A.; Rafferty, C. S.

    1996-11-01

    The diffusion parameters of indium in silicon are investigated. Systematic diffusion experiments in dry oxidizing ambients at temperatures ranging from 800 to 1050 °C are conducted using silicon wafers implanted with indium. Secondary-ion-mass spectrometry (SIMS) is used to analyze the dopant distribution before and after heat treatment. The oxidation-enhanced diffusion parameter [R. B. Fair, in Semiconductor Materials and Process Technology Handbook, edited by G. E. McGuire (Noyes, Park Ridge, NJ, 1988); A. M. R. Lin, D. A. Antoniadis, and R. W. Dutton, J. Electrochem. Soc. Solid-State Sci. Technol. 128, 1131 (1981); D. A. Antoniadis and I. Moskowitz, J. Appl. Phys. 53, 9214 (1982)] and the segregation coefficient at the Si/SiO2 interface [R. B. Fair and J. C. C. Tsai, J. Electrochem. Soc. Solid-State Sci. Technol. 125, 2050 (1978)] (ratio of indium concentration in silicon to that in silicon dioxide) are extracted as a function of temperature using SIMS depth profiles and the silicon process simulator PROPHET [M. Pinto, D. M. Boulin, C. S. Rafferty, R. K. Smith, W. M. Coughran, I. C. Kizilyalli, and M. J. Thoma, in IEDM Technical Digest, 1992, p. 923]. It is observed that the segregation coefficient of indium at the Si/SiO2 interface is mIn?1, similar to boron; however, unlike boron, the segregation coefficient of indium at the Si/SiO2 interface decreases with increasing temperature. Extraction results are summarized in analytical forms suitable for incorporation into other silicon process simulators. Finally, the validity of the extracted parameters is verified by comparing the simulated and measured SIMS profiles for an indium implanted buried-channel p-channel metal-oxide-semiconductor field-effect-transistor [I. C. Kizilyalli, F. A. Stevie, and J. D. Bude, IEEE Electron Device Lett. (1996)] process that involves a gate oxidation and various other thermal processes.

  8. Thermo-Mechanical Processing Parameters for the INCONEL ALLOY 740

    SciTech Connect

    Ludtka, G.M.; Smith, G.

    2007-11-19

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

  9. Quality of margarine: fats selection and processing parameters.

    PubMed

    Miskandar, Mat Sahri; Man, Yaakob Che; Yusoff, Mohd Suria Affandi; Rahman, Russly Abd

    2005-01-01

    Optimum processing conditions on palm oil-based formulations are required to produce the desired quality margarine. As oils and fats contribute to the overall property of the margarine, this paper will review the importance of beta' tending oils and fats in margarine formulation, effects of the processing parameters -- emulsion temperature, flow-rate, product temperature and pin-worker speed -- on palm oil margarines produced and their subsequent behaviour in storage. Palm oil, which contributes the beta' crystal polymorph and the best alternative to hydrogenated liquid fats, and the processing conditions can affect the margarine consistency by influencing the solid fat content (SFC) and the types of crystal polymorph formed during production as well as in storage. Palm oil, or hydrogenated palm oil and olein, in mixture with oils of beta tending, can veer the product to the beta' crystal form. However, merely having beta' crystal tending oils is not sufficient as the processing conditions are also important. The emulsion temperature had no significant effect on the consistency and polymorphic changes of the product during storage, even though differences were observed during processing. The consistency of margarine during storage was high at low emulsion flow-rates and low at high flow rates. The temperature of the scraped-surface tube-cooler is the most important parameter in margarine processing. High temperature will produce a hardened product with formation of beta-crystals during storage. The speed of the pin-worker is responsible for inducing crystallization but, at the same time, destroys the crystal agglomerates, resulting in melting. PMID:16326646

  10. The perils and pitfalls of mining SourceForge

    Microsoft Academic Search

    James Howison; Kevin Crowston

    2004-01-01

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

  11. Optimizing noise control strategy in a forging workshop.

    PubMed

    Razavi, Hamideh; Ramazanifar, Ehsan; Bagherzadeh, Jalal

    2014-01-01

    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

  12. Session Title Forging a Vision for a Sustainable Water Future

    E-print Network

    Barnes, Elizabeth A.

    , Colorado Water Institute Colorado State University John Moore Professor Session Title Forging a Vision for a Sustainable Water Resources Colorado State University Wei Gao Professor, Ecosystem Science

  13. Unraveling the Processing Parameters in Friction Stir Welding

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

    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.

  14. 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.

  15. Characteristics, Process Parameters, and Inner Components of Anaerobic Bioreactors

    PubMed Central

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

    2014-01-01

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

  16. 76 FR 66996 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Forging...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

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

  17. Parameter and Process Significance in Mechanistic Modeling of Cellulose Hydrolysis

    NASA Astrophysics Data System (ADS)

    Rotter, B.; Barry, A.; Gerhard, J.; Small, J.; Tahar, B.

    2005-12-01

    The rate of cellulose hydrolysis, and of associated microbial processes, is important in determining the stability of landfills and their potential impact on the environment, as well as associated time scales. To permit further exploration in this field, a process-based model of cellulose hydrolysis was developed. The model, which is relevant to both landfill and anaerobic digesters, includes a novel approach to biomass transfer between a cellulose-bound biofilm and biomass in the surrounding liquid. Model results highlight the significance of the bacterial colonization of cellulose particles by attachment through contact in solution. Simulations revealed that enhanced colonization, and therefore cellulose degradation, was associated with reduced cellulose particle size, higher biomass populations in solution, and increased cellulose-binding ability of the biomass. A sensitivity analysis of the system parameters revealed different sensitivities to model parameters for a typical landfill scenario versus that for an anaerobic digester. The results indicate that relative surface area of cellulose and proximity of hydrolyzing bacteria are key factors determining the cellulose degradation rate.

  18. Physics and Technological Training in Bulgarian Forge Craft

    NASA Astrophysics Data System (ADS)

    Petkova, Petya N.; Velcheva, Keranka G.

    2010-01-01

    The contemporary world regenerates and preserves the traditions of decorative—applied art and the national crafts. This brings up young generation and helps them to uncover the sources of national culture. In the commonly educational system the technological training realizes succession of new methods for national and applied art. The aim is examination of the national crafts as technological processes for cultivation of different metal constructions. There are enforced physical laws here. Seven basic groups of forging methods consider in Bulgarian tradition craft as heat treatment, plastic deformation and applying of different tensions. This gives information about morphology of construction after applying of stress, enlarging or decreasing of the linear sizes, structure change and the change of physical and mechanical properties.

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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.

  20. 18. INTERIOR VIEW OF ROUGH FORGED TOOLS (FOREGROUND) WHICH ARE ...

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

    18. INTERIOR VIEW OF ROUGH FORGED TOOLS (FOREGROUND) WHICH ARE PRE-HEATED IN THE FURNACE (REAR RIGHT) AND THEN FORGED WITH THE BRADLEY HAMMER (LEFT) AS SHOWN BY JAMES GLASPELL - Warwood Tool Company, Foot of Nineteenth Street, Wheeling, Ohio County, WV

  1. Spark-eroded particles: Influence of processing parameters

    NASA Astrophysics Data System (ADS)

    Carrey, J.; Radousky, H. B.; Berkowitz, A. E.

    2004-02-01

    Ni particles were prepared by spark erosion in a fixed-gap apparatus, and in the usual "shaker-pot" assembly, in an investigation of the influence of various processing parameters on the particles' properties. The sizes of the particles were studied as functions of spark energies ranging from 10 ?J to 1 J, and a scaling relation derived from a simple model was verified. Several different static and rotating electrode configurations were compared with respect to their suitability for producing significant yields of small particles. The advantages of stirring the dielectric with the fixed-gap apparatus and of rotating the electrodes were demonstrated. Water, kerosene, and liquid argon and nitrogen were used as dielectric liquids. When compounds were formed, the reaction with the dielectric proceeded inversely with particle size. Spark erosion in kerosene at low spark energies, followed by annealing, proved to be an effective method to produce fine nickel particles.

  2. Distributed parameter approach to the dynamics of complex biological processes

    SciTech Connect

    Lee, T.T.; Wang, F.Y.; Newell, R.B.

    1999-10-01

    Modeling and simulation of a complex biological process for the removal of nutrients (nitrogen and phosphorus) from municipal wastewater are addressed. The model developed in this work employs a distributed-parameter approach to describe the behavior of components within three different bioreaction zones and the behavior of sludge in the anaerobic zone and soluble phosphate in the aerobic zone in two experiments. Good results are achieved despite the apparent plant-model mismatch, such as uncertainties with the behavior of phosphorus-accumulating organisms. Validation of the proposed secondary-settler model shows that it is superior to two state-of-the-art models in terms of the sum of the square relative errors.

  3. Exploring control parameters of two photon processes in solutions#

    PubMed Central

    GOSWAMI, DEBABRATA; NAG, AMIT

    2013-01-01

    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. PMID:24098068

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

    Microsoft Academic Search

    Peter N Kalu; Lan Zhang

    1998-01-01

    The quest to manufacture low-cost, large complex structures with minimum material wastage has instigated research into near-net shape (NNS) technologies. In this paper, the microstructural and texture evolution in Al-Li 2195 alloy resulting from a specific NNS processing called roll forging was evaluated. The processing consists of five stages and combines conventional ingot conversion (stages I and II), back extrusion

  5. FEM analysis of spur gears forging from nano-structured materials

    NASA Astrophysics Data System (ADS)

    Salcedo, D.; Luis-Pérez, C. J.; Luri, R.; León, J.

    2012-04-01

    The ECAE process is a novel technology which allows us to obtain materials with sub-micrometric and/or nanometric grain size as a result of accumulating very high levels of plastic deformation in the presence of a high hydrostatic pressure. This avoids the fracture of the material and allows us to obtain very high values of plastic deformation (? >>1). Therefore, these nano-structured materials can be used as starting materials for other manufacturing processes such as: extrusion, rolling and forging, among others; with the advantage of providing nanostructure and hence, improved mechanical properties. In this present work, the forging by finite element method (FEM) of materials that have been previously processed by ECAE is analyzed. MSC. MarcTM software will be employed with the aim of analyzing the possibility of manufacturing mechanical components (spur gears) from materials nano-structured by ECAE.

  6. Development of a hybrid neural network system for prediction of process parameters in injection moulding

    Microsoft Academic Search

    Prasad K. D. V. Yarlagadda; Cobby Ang Teck Khong

    2001-01-01

    In this paper, the attempts made by the authors to develop an artificial neural network system for prediction of injection moulding process parameters is presented. In this work, attempts have been made to determine the process parameters that could affect injection moulding process based on governing equations of the filling process. Focus is then directed to parameters that require the

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

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Careno, Stéphanie; Boutin, Olivier; Badens, Elisabeth

    2012-03-01

    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.

  9. Grain size modeling and optimization of rotary forged Alloy 718

    SciTech Connect

    Domblesky, J.P. [Marquette Univ., Milwaukee, WI (United States); Shivpuri, R. [Ohio State Univ., Columbus, OH (United States)

    1997-04-01

    The study presented describes the simulation procedure and methodology used to develop two models for predicting recrystallized grain size in Alloy 718 billet. To simulate multiple pass forging of billet, controlled, high temperature compression testing was used to apply alternate deformation and dwell cycles to Alloy 718 specimens. Grain size obtained by simulation was found to be in excellent agreement with grain size from forged billet when cooling rate was included. The study also revealed that strain per pass and forging temperature were the predominant factors in controlling the recrystallized grain size. Both models were found to accurately predict the recrystallized grain size obtained by compression tests performed at super-solvus temperatures.

  10. Finite Element Method Applied to 2D and 3D Forging Design Optimization

    NASA Astrophysics Data System (ADS)

    Oh, Jin Yong; Yang, Jae Bong; Wu, Wei-Tsu; Delgado, Hugo

    2004-06-01

    In the forging process of complex 2D and 3D parts, multiple intermediate shapes must be used to control metal flow and/or material distribution to ensure proper filling of the finisher die. A systematic method to design an intermediate shape (known as a blocker or a preform) is especially critical for a successful outcome in the forging process. The quality of the blocker/preform design has been highly dependent upon the designer's experience. In order to minimize and ultimately remove the "experience" dependency from the design process, the objective of the current work is to investigate and develop a reliable and practical procedure to systematically carry out the blocker/preform design task. This paper summarizes the overall methodology used for both 2D and 3D preform design problems. Examples are given to demonstrate the capability of the methodology. Sensitivity analysis is used in 2D to achieve the optimal design. The objective function minimizes the variation of strain distribution within the forged component and under-filing and folding are not allowed. A procedure to couple both the filtering technique by using Fourier transform and the FEM was developed for 3D. A blocker/preform design for a complex rib-web type model was achieved by iterating through the filtering method and the FEM simulation. In this example, an under-filing problem was eliminated.

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

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

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

  12. Texture Development During Equal Channel Angular Forging of BCC Metals

    SciTech Connect

    Agnew, S.R.

    1999-08-08

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

  13. Technical bases for precipitate hydrolysis process operating parameters

    SciTech Connect

    Bannochie, C.J.

    1992-10-05

    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).

  14. FOUNDRY SHOP, FORGE SHOP, NORTH ARMORY, EAST ARMORY. Colt ...

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

    FOUNDRY SHOP, FORGE SHOP, NORTH ARMORY, EAST ARMORY. - Colt Fire Arms Company, East Armory Building, 36-150 Huyshope Avenue, 17-170 Van Dyke Avenue, 49 Vredendale Avenue, Hartford, Hartford County, CT

  15. The Networked Forge: New Environments for Libre Software Development

    Microsoft Academic Search

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

    2008-01-01

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

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

    Microsoft Academic Search

    N. R. Chitkara; M. A. Bhutta

    1996-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    Gupta, P. K.

    2014-08-01

    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.

  18. Sensor Data Acquisition and Processing Parameters for Human Activity Classification

    PubMed Central

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

    2014-01-01

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

  19. The effect of some geometric and packaging process parameters on die metallization failure

    Microsoft Academic Search

    A. A. O. Tay; S. H. Ong; Y. K. Lim

    1995-01-01

    This paper describes an experimental and finite element study of the effect of some geometric and packaging process parameters on die metallization failure during temperature cycling. The geometric parameters studied include die size, die offset, voided die attach and metal-line width, while process parameters include molding temperature, molding pressure and moisture preconditioning. A test chip designed to detect passivation and

  20. Control of Groundwater Remediation Process as Distributed Parameter System

    NASA Astrophysics Data System (ADS)

    Mendel, M.; Kovács, T.; Hulkó, G.

    2014-12-01

    Pollution of groundwater requires the implementation of appropriate solutions which can be deployed for several years. The case of local groundwater contamination and its subsequent spread may result in contamination of drinking water sources or other disasters. This publication aims to design and demonstrate control of pumping wells for a model task of groundwater remediation. The task consists of appropriately spaced soil with input parameters, pumping wells and control system. Model of controlled system is made in the program MODFLOW using the finitedifference method as distributed parameter system. Control problem is solved by DPS Blockset for MATLAB & Simulink.

  1. Parameter estimation of multichannel autoregressive processes in noise

    Microsoft Academic Search

    2003-01-01

    We present a new multichannel autoregressive parameter estimation method using a finite set of noisy observations without a priori knowledge of additive noise power. The proposed method is based on solving alternatively a set of nonlinear and a set of linear equations. The Newton–Raphson iteration algorithm is used to estimate the unknown noise variances solving the nonlinear equations while the

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

    E-print Network

    Ko, Kyungduk

    2005-11-01

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

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

    SciTech Connect

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

    1998-06-12

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

  4. Design parameters of boric acid production process from colemanite ore in the presence of propionic acid

    Microsoft Academic Search

    B. Kuskay; A. N. Bulutcu

    2011-01-01

    In this study, three different boric acid production process alternatives which can be performed in the presence of propionic acid and\\/or calcium propionate were evaluated. The process in which calcium propionate is the recycling component was selected as the best alternative and modeled. Some of the design parameters were determined for the selected process. These parameters are solubility change of

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

    Microsoft Academic Search

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

    2008-01-01

    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

  6. Parameter optimization of CO 2 casting process by using Taguchi method

    Microsoft Academic Search

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

    2009-01-01

    This study demonstrates optimization of CO2 casting process parameters by using Taguchi’s design of experiments method. The CO2 casting process involves a large number of parameters affecting the various quality features of the final product. The process\\u000a parameters considered in this research work are weight of CO2 gas, mould hardness number, sand particle size, percentage of sodium silicate, sand mixing

  7. Signal processing for longitudinal parameters of the Tevatron beam

    SciTech Connect

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

    2005-05-01

    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.

  8. Adaptive Filter Solution for Processing Lidar Returns: Optical Parameter Estimation

    NASA Astrophysics Data System (ADS)

    Rocadenbosch, Francesc; Vázquez, Gregori; Comerón, Adolfo

    1998-10-01

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

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

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; OConnor, Kenneth

    2001-01-01

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

  10. INTERVAL APPROACH TO IDENTIFICATION OF PARAMETERS OF EXPERIMENTAL PROCESS

    E-print Network

    Sainudiin, Raazesh

    process [1]: decomposition of H2O2 on bronzes; experiments with high accuracy 3 #12;Possible models of the standard reactant H2O2; fixed volume and initial concentration of various catalysts to be tested; the sameInstitute of Organic Synthesis UrB RAS, Ekaterinburg, Russia, mikushina2006@mail.ru 15th International

  11. PROCESS PLANNING METHOD FOR MASK PROJECTION STEREOLITHOGRAPHY UNDER PARAMETER UNCERTAINTY

    Microsoft Academic Search

    AMEYA LIMAYE

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

  12. Implant for in-vivo parameter monitoring, processing and transmitting

    DOEpatents

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

    2009-11-24

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

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

    SciTech Connect

    Swaminathan, V.P.; Landes, J.D.

    1986-05-01

    Three advanced steel-melting processes - low-sulfur vacuum silicon deoxidation, electroslag remelting, and vacuum carbon deoxidation (VCD) - were applied to produce three CrMoV (ASTM A470, Class 8) steel forgings for steam turbine application. Ingots weighing about 100 t each were produced using these three processes, and rotors were forged with final weights of about 30 t each. Compared to the conventionally produced forgings, the advanced technology forgings show better tensile ductility and better uniformity along the radial and longitudinal directions. Charpy upper-shelf energy shows about 40% improvement, and no temper embrittlement was found using step-cooled and isothermal-aging treatments. Significant improvement in fracture toughness (K/sub IC/ and J/sub IC/) is realized for these forgings. Low-cycle fatigue life is better at high temperatures because of the absence of nonmetallic inclusions. Creep strength shows slight improvement. However, creep ductility is improved, probably because of low residual elements. The VCD forgings show excellent creep ductility, even with long lives. Both the toughness and creep properties are equal to or better than those of oil-quenched rotors produced by European practices. These improvements are attributed to cleaner steel, better control of ingot solidification, low residual elements (especially very low sulfur content), and the associated reduction of nonmetallic inclusions. These three rotors have been placed in service in three operating power plants in units rated at 520 MW each. Volume 1 of this report covers ingot and forging production, and volume 2 covers mechanical property evaluation. 40 refs., 84 figs., 15 tabs.

  14. Parameters related to fiber length and processing in cementitious composites

    Microsoft Academic Search

    Y. Akkaya; A. Peled; S. P. Shah

    2000-01-01

    Effects of fiber length on the tensile and flexural performance of cast and extruded PVA fiber reinforced cement composites\\u000a were investigated. Microstructural characterization, image analysis, and statistical tools were used to study the influence\\u000a of processing and fiber length on fiber-matrix bond, fiber dispersion and fiber orientation in the composites. In the extruded\\u000a composites, shorter fibers improved the performance. In

  15. The Effects of Forming Parameters on Conical Ring Rolling Process

    PubMed Central

    Meng, Wen; Zhao, Guoqun; Guan, Yanjin

    2014-01-01

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

  16. A stochastic process approach of the drake equation parameters

    NASA Astrophysics Data System (ADS)

    Glade, Nicolas; Ballet, Pascal; Bastien, Olivier

    2012-04-01

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

  17. Influence of processing parameters on morphology of polymethoxyflavone in emulsions.

    PubMed

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

    2015-01-21

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

  18. Processing parameters for the development of glass/ceramic MEMS

    NASA Astrophysics Data System (ADS)

    Stillman, J.; Judy, J.; Helvajian, H.

    2007-02-01

    For the past few years we have been investigating the photophysical and photostructurable properties of Foturan, a photostructurable glass ceramic (PSGC) manufactured by Schott Glass Corp. In this paper, we discuss results on using Foturan as a MEMS and MOEMS substrate. Microfabrication in Foturan is possible through patterning by a pulsed UV laser, a subsequent heat treatment step, and chemical etching. In Foturan, the exposed areas undergo a selective phase change in which the native amorphous glass phase converts to a crystalline lithium silicate phase. The degree and type of crystallization are both sensitive functions of the irradiation and thermal processing procedures. Under high exposure dose, the crystallized areas etch up to 30 times faster than the unexposed material in HF, with the etch rate varying with irradiation dose. Because Foturan is transparent at visible through IR wavelengths, direct-write XYZ exposure with a pulsed laser can pattern complex 3-D structures within a sample. Devices made from Foturan may be glass, a glass-ceramic composite, or ceramic, with the final material composition depending on the irradiation and thermal processing procedures. Excellent aspect ratios (>30:1) have already been demonstrated in Foturan. Our interest is in making simple 3-D MEMS structures by implementing cost-effective manufacturing solutions that produce consistent results with a resolution on the order of ten microns.

  19. A method for the determination and hardware validation of biosignal processing parameters

    Microsoft Academic Search

    M. Elena; S. Blasco; J. M. Quero

    2008-01-01

    This paper proposes an iterative procedure for the determination of parameters and working conditions of biomedical signal processing algorithms. A systematization of the process required to determine the parameters is proposed, avoiding “trial and error” tests, and considering all the specific requirements of a Telemedicine system, such as reliability and guaranteed signal reconstruction quality. An application of the method is

  20. Process parameter selection for strontium ferrite sintered magnets using Taguchi L9 orthogonal design

    Microsoft Academic Search

    Puneet Sharma; Amitabh Verma; R. K. Sidhu; O. P. Pandey

    2005-01-01

    The present paper discusses the selection of process parameters for obtaining optimal magnetic properties in strontium ferrite sintered magnets. The magnetic properties have several quality characteristics, such as remanence, coercivity and energy product, etc. To consider these quality characteristics in the selection of process parameters, the Taguchi L9 design is adopted. Experimental results are provided to illustrate the proposed approach.

  1. Estimation of Certain Parameters of a Stationary Hybrid Process Involving a Time Series and a

    E-print Network

    Rigas, Alexandros

    ELSEVIER Estimation of Certain Parameters of a Stationary Hybrid Process Involving a Time Series for estimating the cross-spectral density of a hybrid process involving a time series and a point process. The distribution of the cross-covariance function between a time series and a point process is shown

  2. Physical modeling of the forging of a blade with a damper platform using plasticine

    Microsoft Academic Search

    Mei Zhan; Yuli Liu; He Yang

    2001-01-01

    In order to inspect and analyze the deformation in the forging of a blade with a damper platform, a method of locally making a layer-built billet has been proposed, and physical modeling of the forging of a blade with a damper platform using plasticine has been carried out based on this method. By physical modeling of the forging of a

  3. 76 FR 30200 - Forging Machines; Extension of the Office of Management and Budget's (OMB) Approval of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-24

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

  4. Application of fuzzy expert system to estimate dimensional errors of forging products having complicated shape

    Microsoft Academic Search

    K. S. Park; B. J. Kim; Y. H. Moon

    2007-01-01

    Measurement system that uses mechanical linear displacement sensor and lab view software has been developed to inspect the dimensions of forging products having complicated shape. The measurement system is designed specifically to measure the dimensions of forging products having complicated shape, such as forged outer race of constant velocity (CV) joint having six ball grooves. Newly developed system provides high

  5. A method for the determination and hardware validation of biosignal processing parameters.

    PubMed

    Elena, M; Blasco, S; Quero, J M

    2008-01-01

    This paper proposes an iterative procedure for the determination of parameters and working conditions of biomedical signal processing algorithms. A systematization of the process required to determine the parameters is proposed, avoiding "trial and error" tests, and considering all the specific requirements of a Telemedicine system, such as reliability and guaranteed signal reconstruction quality. An application of the method is included, also, focusing on ECG processing. Hardware platform Biolet(E) is designed for validation in an electronic implementation. PMID:19163321

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

    NASA Astrophysics Data System (ADS)

    Eskil, Murat; Kanca, Erdogan

    2013-09-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    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.

  8. Family Health and Financial Literacy--Forging the Connection

    ERIC Educational Resources Information Center

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

    2009-01-01

    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…

  9. Forging Consensus for Implementing Youth Socialization Policy in Northwest China

    ERIC Educational Resources Information Center

    Fairbrother, Gregory P.

    2011-01-01

    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,…

  10. Electric control and design for automatic precision forging production line

    Microsoft Academic Search

    Gao Junyao; Duan Xingguang; Yang Yigang; He Ming; Wei Boyu

    2009-01-01

    This paper presents a precision forging line of plate spares production. The line include press, robot, heating furnace, convey. Main computer control each device work in coordination with each other. Robots are used to carry spares automatically. The line is automatic control and high efficient, high quality.

  11. Effect of Combustion Air Preheat on a Forged Furnace Productivity 

    E-print Network

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

    1984-01-01

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

  12. The Valley Forge Encampment: Epic on the Schuylkill.

    ERIC Educational Resources Information Center

    Trussell, John B. B., Jr.

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

  13. Effect of chromium and manganese nitride alloying on the evolution of the fine structure in powder hot-forged steels

    NASA Astrophysics Data System (ADS)

    Mamonova, A. A.; Baglyuk, G. A.; Kurovskii, V. Ya.

    2015-06-01

    The effect of alloying with chromium and manganese nitrides is studied on a fine crystal structure of powder iron produced by hot forging. The features of the fine structure and the phase composition are found to strongly depend on the kind of alloying nitrides. It has been shown that the introduction of both nitrides in the initial composition of powder mixture causes an increase in the lattice parameter of a matrix, its defectiveness, and the dislocation density, which results in an increase in the hardness of steel alloyed with nitrides. The defectiveness of the matrix crystal lattice, the dislocation density, and the hardness of hot-forged steels are slightly higher when manganese nitride is used as a nitrogen-bearing additive.

  14. AIAA-2003-0694 QUANTIFICATION OF PROCESSING PARAMETERS FOR WIND TURBINE

    E-print Network

    AIAA-2003-0694 QUANTIFICATION OF PROCESSING PARAMETERS FOR WIND TURBINE BLADES Douglas Cairns, John of processing techniques and can be useful to wind turbine blade manufacturers to prepare processing conditions-3]. This is a consequence of the typical material architectures that are used in wind turbine blades. Figure 1

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

    Microsoft Academic Search

    Prasad K. D. V Yarlagadda

    2002-01-01

    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

  16. Analysis of Leaf Parameters Measurement of Cucumber Based on Image Processing

    Microsoft Academic Search

    You-wen Tian; Xiao-juan Wang

    2009-01-01

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

  17. A Computer System Measuring the Electrical Parameters of Microplasma Processes in Solutions

    Microsoft Academic Search

    A. I. Mamaev; V. N. Borikov; V. A. Mamaeva; T. I. Dorofeeva

    2005-01-01

    A computer-aided system developed measures the electrical parameters of high pulse-current processes in solutions, including precisely determining the shape and form of high-voltage signals of the electrochemical cell. The shape changes in the electrical signals of microplasma processes are revealed as a function of the bath, as well as working electrode, composition and the process time.

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

    E-print Network

    Cao, Longbing

    A NOVEL AUTO-PARAMETERS SELECTION PROCESS FOR IMAGE SEGMENTATION Yunzhi Jianga,b , Pohsiang Tsai ABSTRACT Segmentation is a process to obtain the desirable features in image processing. However, the existing techniques that use the multilevel thresholding method in image segmentation are computationally

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

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

    Microsoft Academic Search

    Gül Tosun

    2011-01-01

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

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

    E-print Network

    Cullinan, Michael A. (Michael Arthur)

    2008-01-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    E-print Network

    Skogestad, Sigurd

    Optimal Selection of Sensors & Controller Parameters for Economic Optimization of Process Plants precision, etc. If active constraints are perfectly controllable and nuc,dof > 0 (Obj. 1) Design sensor and parametric decisions Focus: Selection of measurements, set point and controller parameters Nabil M (IIT

  4. A novel separation process for olefin gas purification: Effect of operating parameters on separation performance and process optimization

    Microsoft Academic Search

    Maryam Takht Ravanchi; Tahereh Kaghazchi; Ali Kargari; Mansoureh Soleimani

    2009-01-01

    Separation of propylene–propane mixtures using facilitated transport membrane is potentially a novel separation process for olefin gas purification. The main purpose of this study was to find optimum values of the process parameters using the Taguchi approach. The Taguchi method was selected as the statistical technique since it allows the main effects to be estimated with a minimum number of

  5. Interdependency Study of Process and Design Parameter Scaling for Power Optimization of Nano-CMOS Circuits under Process Variation

    E-print Network

    Mohanty, Saraju P.

    Interdependency Study of Process and Design Parameter Scaling for Power Optimization of Nano-CMOS Circuits under Process Variation Abstract In sub-65nm CMOS technology, switching power and gate as well paths in a nano- CMOS transistor during power dissipation in different states of operation [4, 16, 24

  6. Process technology and design parameter impact on SRAM Bit-Cell Sleep effectiveness

    Microsoft Academic Search

    Guru Shamanna; B. S. Kshatri; R. Gaurav; Y. S. Tew; P. Marfatia; Y. Raghavendra; V. Naik

    2010-01-01

    SRAM Bit-Cell Sleep technique is extensively used in processors to minimize SRAM leakage power. However, magnitude of leakage power savings from SRAM bit-cell sleep technique is dependent on process technology and various design parameters. This paper analyzes influence of design parameters like VCCMIN_RET, DVS, ITD and NBTI on effectiveness of SRAM bit-cell sleep scheme. Impact of Process Technology on SRAM

  7. Path properties of kernel generated two-time parameter Gaussian processes

    Microsoft Academic Search

    Miklós Csörg?; Zhengyan Lin

    1991-01-01

    Summary We study path properties of two-parameter Gaussian processes {X(t,v),t ?R} of the formX(t,v)=?08-88G(t,v,x,y)dW(x,y), where the kernel function G(t, v, x, y) is assumed to be square integrable in (x, y) onR×R+, andW(x, y) is a standard two-parameter Wiener process.

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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.

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

    Microsoft Academic Search

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

    2007-01-01

    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

  10. Influence of the process parameters on the ESD synthesis of thin film YSZ electrolytes

    Microsoft Academic Search

    Roberto Neagu; Dainius Perednis; Agnès Princivalle; Elisabeth Djurado

    2006-01-01

    This paper presents the results of a process optimisation study applied to the synthesis of thin 8YSZ films by electrostatic spray deposition (ESD). The goal was to obtain thin, dense and continuous 8YSZ coatings. Starting from a zirconium acetylacetonate in ethanol – butyl carbitol solution as precursor, the influence of the main process parameters – substrate temperature, nozzle to substrate

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

    Microsoft Academic Search

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

    1999-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  13. Effects of the Deslagging Process on some Physicochemical Parameters of Honey

    PubMed Central

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

    2015-01-01

    Some physicochemical parameters of honey have been introduced by the International Honey Commission to evaluate its quality and origin but processes such as heating and filtering can affect these parameters. In traditional Iranian medicine, deslagging process involves boiling honey in an equal volume of water and removing the slag formed during process. The aim of this study was to determine the effects of deslagging process on parameters of color intensity, diastase evaluation, electrical conductivity, pH, free acidity, refractive index, hydroxy methyl furfural (HMF), proline and water contents according to the International Honey Committee (IHC) standards. The results showed that deslagged honey was significantly different from control honey in terms of color intensity, pH, diastase number, HMF and proline content. It can be concluded that the new standards are needed to regulate deslagged honey. PMID:25901175

  14. Performance Assessment Method for a Forged Fingerprint Detection Algorithm

    NASA Astrophysics Data System (ADS)

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

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

  15. Microstructural heterogeneity of forged rolled rings

    Microsoft Academic Search

    J. Herian

    Purpose: The paper presents the processes which condition the quality of steel cast strands and properties of rolled products. It touches upon the technology of small-size rings manufacture from the 42CrMo4 steel used for the production of rolling bearings and toothed rings. Design\\/methodology\\/approach: Investigations were made on the 42CrMo4 steel based process of small-size rings manufacture of weight not exceeding

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

    NASA Astrophysics Data System (ADS)

    Wegner, Andreas; Witt, Gerd

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

  17. Cellular scanning strategy for selective laser melting: Generating reliable, optimized scanning paths and processing parameters

    NASA Astrophysics Data System (ADS)

    Mohanty, Sankhya; Hattel, Jesper H.

    2015-03-01

    Selective laser melting is yet to become a standardized industrial manufacturing technique. The process continues to suffer from defects such as distortions, residual stresses, localized deformations and warpage caused primarily due to the localized heating, rapid cooling and high temperature gradients that occur during the process. While process monitoring and control of selective laser melting is an active area of research, establishing the reliability and robustness of the process still remains a challenge. In this paper, a methodology for generating reliable, optimized scanning paths and process parameters for selective laser melting of a standard sample is introduced. The processing of the sample is simulated by sequentially coupling a calibrated 3D pseudo-analytical thermal model with a 3D finite element mechanical model. The optimized processing parameters are subjected to a Monte Carlo method based uncertainty and reliability analysis. The reliability of the scanning paths are established using cumulative probability distribution functions for process output criteria such as sample density, thermal homogeneity, etc. A customized genetic algorithm is used along with the simulation model to generate optimized cellular scanning strategies and processing parameters, with an objective of reducing thermal asymmetries and mechanical deformations. The optimized scanning strategies are used for selective laser melting of the standard samples, and experimental and numerical results are compared.

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

    SciTech Connect

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

    2011-01-17

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

  19. Detection of dominant modelled nitrate processes with a high temporally resolved parameter sensitivity analysis

    NASA Astrophysics Data System (ADS)

    Haas, Marcelo; Guse, Björn; Pfannerstill, Matthias; Fohrer, Nicola

    2015-04-01

    The river systems in the catchment are impacted by nutrient inputs from different sources of the landscape. The input of nitrate from agricultural areas into the river systems is related to numerous processes which occur simultaneously and influence each other permanently. These complex nitrate processes are represented in eco-hydrological models. To obtain reliable future predictions of nitrate concentrations in rivers, the nitrogen cycle needs to be reproduced accurately in these models. For complex research questions dealing with nitrate impacts, it is thus essential to better understand the nitrate process dynamics in models and to reduce the uncertainties in water quality predictions. This study aims to improve the understanding of nitrate process dynamics by using a temporal parameter sensitivity analysis, which is applied on an eco-hydrological model. With this method, the dominant model parameters are detected for each day. Thus, by deriving temporal variations in dominant model parameters, the nitrate process dynamic is investigated for phases with different conditions for nitrate transport and transformations. The results show that the sensitivity of different nitrate parameters varies temporally. These temporal dynamics in dominant parameters are explained by temporal variations in nitrate transport and plant uptake processes. An extended view on the dynamics of the temporal parameter sensitivity is obtained by analysing different modelled runoff components and nitrate pathways. Thereby, the interpretation of seasonal variations in dominant nitrate pathways is assisted and a better understanding of the role of nitrate in the environment is achieved. We conclude that this method improves the reliability of modelled nitrate processes. In this way, a better basis for recent and future scenarios of nitrate loads management is provided.

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

    Microsoft Academic Search

    Mohammad Vaezi; Chee Kai Chua

    2011-01-01

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

  1. Simultaneous estimation of process parameters, noise variance, and signal-to-noise ratio

    Microsoft Academic Search

    S. Niu; D. Grant Fisher

    1995-01-01

    An efficient and convenient method is developed for the online estimation of the noise variance and signal-to-noise ratio (SNR) of real processes. The method can be incorporated into most parameter estimation algorithms but is particularly appropriate for the augmented UD identification (AUDI) algorithm. The on-line estimates of the variance, SNR, and parameters can be used directly in applications such as

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

    Microsoft Academic Search

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

    2006-01-01

    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

  3. Process parameter dependent growth phenomena of naproxen nanosuspension manufactured by wet media milling.

    PubMed

    Bitterlich, A; Laabs, C; Krautstrunk, I; Dengler, M; Juhnke, M; Grandeury, A; Bunjes, H; Kwade, A

    2015-05-01

    The production of nanosuspensions has proved to be an effective method for overcoming bioavailability challenges of poorly water soluble drugs. Wet milling in stirred media mills and planetary ball mills has become an established top-down-method for producing such drug nanosuspensions. The quality of the resulting nanosuspension is determined by the stability against agglomeration on the one hand, and the process parameters of the mill on the other hand. In order to understand the occurring dependencies, a detailed screening study, not only on adequate stabilizers, but also on their optimum concentration was carried out for the active pharmaceutical ingredient (API) naproxen in a planetary ball mill. The type and concentration of the stabilizer had a pronounced influence on the minimum particle size obtained. With the best formulation the influence of the relevant process parameters on product quality was investigated to determine the grinding limit of naproxen. Besides the well known phenomenon of particle agglomeration, actual naproxen crystal growth and morphology alterations occurred during the process which has not been observed before. It was shown that, by adjusting the process parameters, those effects could be reduced or eliminated. Thus, besides real grinding and agglomeration a process parameter dependent ripening of the naproxen particles was identified to be a concurrent effect during the naproxen fine grinding process. PMID:25766272

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

    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.

  5. Workability in forging of powder metallurgy compacts

    Microsoft Academic Search

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

    1995-01-01

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

  6. Assessment of the high-frequency mechanical forging mode effect on fatigue strength of welded joints

    Microsoft Academic Search

    V. A. Degtyarev

    2011-01-01

    We present results of fatigue testing of strengthened butt-welded joints of St. 3sp steel subjected to various modes of high-frequency\\u000a mechanical forging. As the treatment effectiveness criterion, we propose to use the groove depth in the work-hardened area.\\u000a The optimal values of groove depth and high-frequency mechanical forging rates have been determined at various vibration amplitudes\\u000a of the forging tool,

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    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.

  9. Evaluation of Tensile Deformation Properties of Friction Stir Processed Pure Copper: Effect of Processing Parameters and Pass Number

    NASA Astrophysics Data System (ADS)

    Barmouz, Mohsen; Besharati Givi, Mohammad Kazem; Jafari, Jalal

    2014-01-01

    In this work, the tensile behavior of pure copper including ultimate tensile stress, yield stress, and elongation in the specimens friction stir processed under different processing parameters and pass adding was investigated in detail. The effect of strain hardening, grain refinement, and heat input on the tensile properties of these specimens was explained as well. It was observed that, regarding the aforementioned factors, the processing parameters and pass number could have considerable effects on the tensile deformation properties of the pure copper such as 300 and 47% enhancements in elongation and ultimate strength, respectively. It was demonstrated that higher passes resulted in the development of ultrafine grains (up to 700-800 nm) in the specimens. The fracture surface morphology was also used to further support the elongation results.

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

    SciTech Connect

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

    2012-11-14

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

  11. Experimental Methodology for Determining Optimum Process Parameters for Production of Hydrous Metal Oxides by Internal Gelation

    SciTech Connect

    Collins, J.L.

    2005-10-28

    The objective of this report is to describe a simple but very useful experimental methodology that was used to determine optimum process parameters for preparing several hydrous metal-oxide gel spheres by the internal gelation process. The method is inexpensive and very effective in collection of key gel-forming data that are needed to prepare the hydrous metal-oxide microspheres of the best quality for a number of elements.

  12. High temperature short time air puffed ready-to-eat (RTE) potato snacks: Process parameter optimization

    Microsoft Academic Search

    A. Nath; P. K. Chattopadhyay; G. C. Majumdar

    2007-01-01

    Ready-to-eat (RTE) potato snacks were developed with high temperature short time (HTST) air puffing process based on centre composite RSM design. The effects of process parameters viz. puffing temperature (175–275°C), puffing time (15–75s), initial moisture content (30–40%) and air velocity (2.4–4.8m\\/s) on quality attributes such as expansion ratio, hardness, ascorbic acid loss and overall acceptability of the products were investigated.

  13. Denitrification of brackish water by electrodialysis: Effect of process parameters and water characteristics

    Microsoft Academic Search

    Mourad Ben Sik Ali; Amine Mnif; Bechir Hamrouni; Mahmoud Dhahbi

    2010-01-01

    The aim of this work is to study the removal of nitrate from brackish polluted water using electrodialysis. The influence\\u000a of several parameters, such as flow rates, initial feed concentration, co-existing anions and initial pH on process efficiency\\u000a were studied. This efficiency is evaluated by the removal rate, demineralization rate and power consumption. The denitrification\\u000a process showed to be independent

  14. Tailoring carbon nanotips in the plasma-assisted chemical vapor deposition: Effect of the process parameters

    SciTech Connect

    Wang, B. B. [CSIRO Materials Science and Engineering, P.O. Box 218, Lindfield NSW 2070 (Australia); College of Mathematics and Physics, Chongqing Institute of Technology, Chongqing, 400054 (China); Ostrikov, K. [CSIRO Materials Science and Engineering, P.O. Box 218, Lindfield NSW 2070 (Australia)

    2009-04-15

    Carbon nanotips have been synthesized from a thin carbon film deposited on silicon by bias-enhanced hot filament chemical vapor deposition under different process parameters. The results of scanning electron microscopy indicate that high-quality carbon nanotips can only be obtained under conditions when the ion flux is effectively drawn from the plasma sustained in a CH{sub 4}+NH{sub 3}+H{sub 2} gas mixture. It is shown that the morphology of the carbon nanotips can be controlled by varying the process parameters such as the applied bias, gas pressure, and the NH{sub 3}/H{sub 2} mass flow ratios. The nanotip formation process is examined through a model that accounts for surface diffusion, in addition to sputtering and deposition processes included in the existing models. This model makes it possible to explain the major difference in the morphologies of the carbon nanotips formed without and with the aid of the plasma as well as to interpret the changes of their aspect ratio caused by the variation in the ion/gas fluxes. Viable ways to optimize the plasma-based process parameters to synthesize high-quality carbon nanotips are suggested. The results are relevant to the development of advanced plasma-/ion-assisted methods of nanoscale synthesis and processing.

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

    NASA Astrophysics Data System (ADS)

    Shukla, Alok; Bajpai, P. K.

    2011-11-01

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

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

    SciTech Connect

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

    2014-04-15

    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.

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

    NASA Technical Reports Server (NTRS)

    Orme, John S.; Gilyard, Glenn B.

    1992-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Li, Xuefeng; Cao, Guangzhan; Liu, Hongjun

    2014-04-01

    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.

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

    Microsoft Academic Search

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

    2000-01-01

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

  20. Advanced Statistical Optimization of Parameters of Synthesis Process of Oxygenated Carbonated Apatite

    Microsoft Academic Search

    H. Chaair; S. Belouafa; K. Digua; B. Sallek; H. Oudadesse; L. Mouhir

    2008-01-01

    The synthesis process of oxygenated carbonated apatite was optimized by an advanced statistical planning of experiments. Full factorial design of 24 experiments was used to find the effects of five principal parameters: pH of the reaction medium, atomic ratio Ca\\/P of the reagents, concentration of the calcium solution (Ca), temperature of the reaction medium (T) and duration of the reaction

  1. Effective parameters in axial injection suspension plasma spray process of alumina-zirconia ceramics

    E-print Network

    Medraj, Mamoun

    Effective parameters in axial injection suspension plasma spray process of alumina- zirconia in the system. Using feedstock mixtures for composite coatings, such as alumina and zirconia, intricacy plasma spray conditions and resulting coating microstructure and defects. In this study, an alumina/ 8 wt

  2. Parameter identification for an autonomous 11th order nonlinear model of a physiological process

    Microsoft Academic Search

    A. Rundell; R. DeCarlo; P. Doerschuk; H. HogenEsch

    1998-01-01

    This paper sets forth and illustrates some techniques for parameter identification (PId) of a nonlinear state model that approximates the dynamical behavior of the humoral immune response of a human to Haemophilus influenzae Type-b. The natural physiological time-separation of the primary, late follicular, and secondary immune responses of this biological process allows one to divide the PId problem into a

  3. Laser materials processing with dynamic-beam parameters in the focus region

    NASA Astrophysics Data System (ADS)

    Staupendahl, Gisbert; Bliedtner, Jens; Schott, Thomas

    1993-05-01

    This paper reports on a new arrangement for laser materials processing allowing the fast variation of beam parameters in the focus region, e.g., the polarization of the radiation and the diameter and position of the focus spot. Results of CO2 laser cutting of mild steel with a dynamic polarization are discussed.

  4. Identification of CTOA and fracture process parameters by drop weight test and finite element simulation

    Microsoft Academic Search

    P. Salvini; A. Fonzo; G. Mannucci

    2003-01-01

    This paper presents a new technique that is able to predict ductile fracture propagation occurrences in large metallic structures, by means of an appropriate application of the finite element modelling. This technique takes account of a cohesive zone in the vicinity of the crack tip, where a nodal release technique is implemented. Two parameters, governing the process zone of the

  5. Prediction of forming limits and parameters in the tube hydroforming process

    Microsoft Academic Search

    Muammer Koca; Taylan Altan

    2002-01-01

    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

  6. Prediction of forming limits and parameters in the tube hydroforming process

    Microsoft Academic Search

    Muammer Koç; Taylan Altan

    2002-01-01

    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.

  7. Equipment and methods used to investigate energy processing parameters of sewing technology operations

    Microsoft Academic Search

    Dubravko Rogale; Igor Petruni?; Zvonko Drag?evi?; Snježana Firšt Rogale

    2005-01-01

    Purpose – The equipment for computerised measuring of electrical power and energy is presented, adapted to the needs of investigating processing parameters of garment sewing operations. Design\\/methodology\\/approach – The method of measuring the energy necessary to run the sewing-machine driving electrical motor is also presented, correlated to the stitching speed in joining a straight seam in a single, two, or

  8. Impact of Layout on 90nm CMOS Process Parameter Fluctuations Liang-Teck Pang, Borivoje Nikolic

    E-print Network

    Nikolic, Borivoje

    Impact of Layout on 90nm CMOS Process Parameter Fluctuations Liang-Teck Pang, Borivoje Nikolic University of California, Berkeley, USA Abstract A test chip has been built to study the effects of layout magnitude of WID and D2D variations, its spatial correlation, and the impact of layout styles. The chip

  9. An hybrid ensemble based approach for process parameter estimation in offshore oil platforms

    E-print Network

    Paris-Sud XI, Université de

    An hybrid ensemble based approach for process parameter estimation in offshore oil platforms Piero in offshore oil platforms. In particular, the difference between the theoretical value of the valve flow on real measurements performed on a number of similar offshore choke valves. 1. Introduction In this paper

  10. Adaptive Parameter Estimation of Person Recognition Model in a Stochastic Human Tracking Process

    NASA Astrophysics Data System (ADS)

    Nakanishi, W.; Fuse, T.; Ishikawa, T.

    2015-05-01

    This paper aims at an estimation of parameters of person recognition models using a sequential Bayesian filtering method. In many human tracking method, any parameters of models used for recognize the same person in successive frames are usually set in advance of human tracking process. In real situation these parameters may change according to situation of observation and difficulty level of human position prediction. Thus in this paper we formulate an adaptive parameter estimation using general state space model. Firstly we explain the way to formulate human tracking in general state space model with their components. Then referring to previous researches, we use Bhattacharyya coefficient to formulate observation model of general state space model, which is corresponding to person recognition model. The observation model in this paper is a function of Bhattacharyya coefficient with one unknown parameter. At last we sequentially estimate this parameter in real dataset with some settings. Results showed that sequential parameter estimation was succeeded and were consistent with observation situations such as occlusions.

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

    Microsoft Academic Search

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

    2010-01-01

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

  12. Development of process parameters for 22 nm PMOS using 2-D analytical modeling

    NASA Astrophysics Data System (ADS)

    Maheran, A. H. Afifah; Menon, P. S.; Ahmad, I.; Shaari, S.; Faizah, Z. A. Noor

    2015-04-01

    The complementary metal-oxide-semiconductor field effect transistor (CMOSFET) has become major challenge to scaling and integration. Innovation in transistor structures and integration of novel materials are necessary to sustain this performance trend. CMOS variability in the scaling technology becoming very important concern due to limitation of process control; over statistically variability related to the fundamental discreteness and materials. Minimizing the transistor variation through technology optimization and ensuring robust product functionality and performance is the major issue.In this article, the continuation study on process parameters variations is extended and delivered thoroughly in order to achieve a minimum leakage current (ILEAK) on PMOS planar transistor at 22 nm gate length. Several device parameters are varies significantly using Taguchi method to predict the optimum combination of process parameters fabrication. A combination of high permittivity material (high-k) and metal gate are utilized accordingly as gate structure where the materials include titanium dioxide (TiO2) and tungsten silicide (WSix). Then the L9 of the Taguchi Orthogonal array is used to analyze the device simulation where the results of signal-to-noise ratio (SNR) of Smaller-the-Better (STB) scheme are studied through the percentage influences of the process parameters. This is to achieve a minimum ILEAK where the maximum predicted ILEAK value by International Technology Roadmap for Semiconductors (ITRS) 2011 is said to should not above 100 nA/µm. Final results shows that the compensation implantation dose acts as the dominant factor with 68.49% contribution in lowering the device's leakage current. The absolute process parameters combination results in ILEAK mean value of 3.96821 nA/µm where is far lower than the predicted value.

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

    NASA Astrophysics Data System (ADS)

    Hajihashemi, Mahdi; Niroumand, Behzad; Shamanian, Morteza

    2015-04-01

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

  14. SourceForge.net: Project of the Month

    NSDL National Science Digital Library

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

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

    PubMed Central

    Deshmukh, Ketkee; Amin, Purnima

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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.

  17. Kinetic parameters estimation in an anaerobic digestion process using successive quadratic programming.

    PubMed

    Aceves-Lara, C A; Aguilar-Garnica, E; Alcaraz-González, V; González-Reynoso, O; Steyer, J P; Dominguez-Beltran, J L; González-Alvarez, V

    2005-01-01

    In this work, an optimization method is implemented in an anaerobic digestion model to estimate its kinetic parameters and yield coefficients. This method combines the use of advanced state estimation schemes and powerful nonlinear programming techniques to yield fast and accurate estimates of the aforementioned parameters. In this method, we first implement an asymptotic observer to provide estimates of the non-measured variables (such as biomass concentration) and good guesses for the initial conditions of the parameter estimation algorithm. These results are then used by the successive quadratic programming (SQP) technique to calculate the kinetic parameters and yield coefficients of the anaerobic digestion process. The model, provided with the estimated parameters, is tested with experimental data from a pilot-scale fixed bed reactor treating raw industrial wine distillery wastewater. It is shown that SQP reaches a fast and accurate estimation of the kinetic parameters despite highly noise corrupted experimental data and time varying inputs variables. A statistical analysis is also performed to validate the combined estimation method. Finally, a comparison between the proposed method and the traditional Marquardt technique shows that both yield similar results; however, the calculation time of the traditional technique is considerable higher than that of the proposed method. PMID:16180459

  18. Comparison of flow patterns between plasticine and aluminium alloys in hot-precision forging

    Microsoft Academic Search

    H. So; Y. F. Lin; K. W. Huang

    1997-01-01

    Flow patterns, folding problems and die filling in hot precision forging of aluminium alloys are simulated by physical modelling using plasticine. In order to study the reliability of the simulation, a forged product of complex geometry has been chosen. It is found that only the correct direction of the layers of the stacked plasticine blanks can have a similar folding

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

    Microsoft Academic Search

    Komei Suzuki; Ikuo Sato; Mikio Kusuhashi; Hisashi Tsukada

    2000-01-01

    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

  20. Near-net shape forging of spur gear forms: An analysis and some experiments

    Microsoft Academic Search

    N. R. Chitkara; M. A. Bhutta

    1996-01-01

    The paper presents the results of an experimental investigation carried out in quasi-static incremental upset-forging of spur gear forms around the periphery of initially solid cylindrical billets, the outer radius of each of which was of the same size as the radius of the dedendum circle of the spur gear to be forged. The punch or die used was of

  1. Novel forging technology of a magnesium alloy impeller with twisted blades of micro-thickness

    Microsoft Academic Search

    J. H. Lee; S. H. Kang; D. Y. Yang

    2008-01-01

    In this work, a novel forging technology has been developed to produce a magnesium alloy impeller with twisted blades of micro-thickness used in a fuel cell system. Due to the very complicated blades of the impeller, a specially designed split die was adopted for successful forging of the impeller. In this split die-set, the coherence of reinforcement ring and split

  2. 77 FR 23496 - Boundary Revision of Valley Forge National Historical Park

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-19

    ...boundary of Valley Forge National Historical Park, pursuant to the authority...depicted on Legislative Boundary Map Number 464/108056, entitled ``Valley Forge National Historical Park Proposed Boundary Expansion...dated June 27, 2011. This map is on file and available...

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

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

    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.

  4. Modelling of influential parameters on a continuous evaporation process by Doehlert shells

    PubMed Central

    Porte, Catherine; Havet, Jean-Louis; Daguet, David

    2003-01-01

    The modelling of the parameters that influence the continuous evaporation of an alcoholic extract was considered using Doehlert matrices. The work was performed with a wiped falling film evaporator that allowed us to study the influence of the pressure, temperature, feed flow and dry matter of the feed solution on the dry matter contents of the resulting concentrate, and the productivity of the process. The Doehlert shells were used to model the influential parameters. The pattern obtained from the experimental results was checked allowing for some dysfunction in the unit. The evaporator was modified and a new model applied; the experimental results were then in agreement with the equations. The model was finally determined and successfully checked in order to obtain an 8% dry matter concentrate with the best productivity; the results fit in with the industrial constraints of subsequent processes. PMID:18924887

  5. Tailoring of processing parameters for sintering microsphere-based scaffolds with dense-phase carbon dioxide

    PubMed Central

    Jeon, Ju Hyeong; Bhamidipati, Manjari; Sridharan, BanuPriya; Scurto, Aaron M.; Berkland, Cory J.; Detamore, Michael S.

    2015-01-01

    Microsphere-based polymeric tissue-engineered scaffolds offer the advantage of shape-specific constructs with excellent spatiotemporal control and interconnected porous structures. The use of these highly versatile scaffolds requires a method to sinter the discrete microspheres together into a cohesive network, typically with the use of heat or organic solvents. We previously introduced subcritical CO2 as a sintering method for microsphere-based scaffolds; here we further explored the effect of processing parameters. Gaseous or subcritical CO2 was used for making the scaffolds, and various pressures, ratios of lactic acid to glycolic acid in poly(lactic acid-co-glycolic acid), and amounts of NaCl particles were explored. By changing these parameters, scaffolds with different mechanical properties and morphologies were prepared. The preferred range of applied subcritical CO2 was 15–25 bar. Scaffolds prepared at 25 bar with lower lactic acid ratios and without NaCl particles had a higher stiffness, while the constructs made at 15 bar, lower glycolic acid content, and with salt granules had lower elastic moduli. Human umbilical cord mesenchymal stromal cells (hUCMSCs) seeded on the scaffolds demonstrated that cells penetrate the scaffolds and remain viable. Overall, the study demonstrated the dependence of the optimal CO2 sintering parameters on the polymer and conditions, and identified desirable CO2 processing parameters to employ in the sintering of microsphere-based scaffolds as a more benign alternative to heat-sintering or solvent-based sintering methods. PMID:23115065

  6. Effect of process parameters on springback behaviour during air bending of electrogalvanised steel sheet

    Microsoft Academic Search

    Durairaj Vasudevan; Rajumani Srinivasan; Palani Padmanabhan

    2011-01-01

    This work aims to study the springback behaviour of electrogalvanised (EG) steel sheets during the air bending process. Experiments\\u000a have been conducted to analyse the influence of various parameters such as coating thickness, orientation of the sheet, punch\\u000a radius, die radius, die opening, punch velocity, and punch travel on springback behaviour. It is established that the springback\\u000a increases with increasing

  7. Ergodicity and Parameter Estimates for Infinite-Dimensional Fractional Ornstein-Uhlenbeck Process

    SciTech Connect

    Maslowski, Bohdan [Czech Academy of Sciences, Institute of Mathematics (Czech Republic)], E-mail: maslow@math.cas.cz; Pospisil, Jan [University of West Bohemia, Faculty of Applied Sciences, Department of Mathematics (Czech Republic)], E-mail: jan.pospisil@kma.zcu.cz

    2008-06-15

    Existence and ergodicity of a strictly stationary solution for linear stochastic evolution equations driven by cylindrical fractional Brownian motion are proved. Ergodic behavior of non-stationary infinite-dimensional fractional Ornstein-Uhlenbeck processes is also studied. Based on these results, strong consistency of suitably defined families of parameter estimators is shown. The general results are applied to linear parabolic and hyperbolic equations perturbed by a fractional noise.

  8. On continuous and discrete sampling for parameter estimation in diffusion type processes

    Microsoft Academic Search

    A. LE BRETON

    This paper is concerned with the problem of estimation of the drift parameter ? in a linear stochastic differential equation,\\u000a with constant coefficients. When continuous sampling of the solution process is available, the maximum likelihood estimate\\u000a [^(q<\\/font\\u000a>)] t<\\/font\\u000a>\\\\hat \\\\theta _\\\\tau, based on observation in [0, T] is defined in terms of stochastic and ordinary integrals. So, in practice,

  9. Parameter optimization of the sheet metal forming process using an iterative parallel Kriging algorithm

    Microsoft Academic Search

    J. Jakumeit; M. Herdy; M. Nitsche

    2005-01-01

    Different numerical optimization strategies were used to find an optimized parameter setting for the sheet metal forming process. A parameterization of a time-dependent blank-holder force was used to control the deep-drawing simulation. Besides the already well-established gradient and direct search algorithms and the response surface method the novel Kriging approach was used as an optimization strategy. Results for two analytical

  10. Numerical simulation of linear friction welding of titanium alloy: Effects of processing parameters

    Microsoft Academic Search

    Wen-Ya Li; Tiejun Ma; Jinglong Li

    2010-01-01

    Numerical modeling of linear friction welding (LFW) of TC4 titanium alloy was conducted using ABAQUS\\/Explicit with a 2D model. The coupled thermo-mechanical analysis was performed with the Johnson–Cook material model. The effects of processing parameters on the temperature evolution and axial shortening of LFW joints were numerically investigated. It is shown that the temperature at the interface can first increase

  11. Optimization of Process Parameters in Vertical CNC Mill Machines Using Taguchi's Design of Experiments

    Microsoft Academic Search

    Dalgobind MAHTO; Anjani KUMAR

    With the more precise demands of modern engineering products, the control of surface texture together with dimensional accuracy has become more important. This paper outlines the Taguchi optimization methodology, which is applied to optimize cutting parameters in end milling operation. The study was conducted in machining operation in hardened steel DIN GX40CRMOV5-1. The processing of the job was done by

  12. Influence of EDM process parameters in deep hole drilling of Inconel 718

    Microsoft Academic Search

    P. Kuppan; A. Rajadurai; S. Narayanan

    2008-01-01

    This paper reports on an experimental investigation of small deep hole drilling of Inconel 718 using the EDM process. The\\u000a parameters such as peak current, pulse on-time, duty factor and electrode speed were chosen to study the machining characteristics.\\u000a An electrolytic copper tube of 3 mm diameter was selected as a tool electrode. The experiments were planned using central\\u000a composite design

  13. Effects of process parameters on sulfur removal efficiency in a fluidized bed

    SciTech Connect

    Sahan, R.A. [Lehigh Univ., Bethlehem, PA (United States). Dept. of Mechanical Engineering and Mechanics

    1995-12-31

    The effects of coal properties and process parameters, such as fluidized bed depth, superficial gas velocity, coal to magnetite feed weight ratio and processing time, on coal cleaning efficiency was experimentally studied in a bubbling fluidized bed separator. The coal cleaning experiments were performed with one various size fractions of Pennsylvania`s bituminous coals, Rushton coal. The performance of the coal cleaning process was measured with the aid of sulfur and ash removal efficiencies. Previous experimental results and those obtained in this study indicated that, when operated in optimum process conditions, coal particle sizes smaller than 240 {micro}m and larger than 143 {micro}m can be cleaned with high performance in the fluidized bed separator. For coal particle sizes smaller than 143 {micro}m, high interparticle cohesive forces caused slugging and channeling inside the bed. As a result of this, relatively poor cleaning performance was recorded for very fine size fraction of Rushton coal.

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

    NASA Technical Reports Server (NTRS)

    Orme, John S.; Gilyard, Glenn B.

    1992-01-01

    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.

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

    PubMed

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

    2012-12-01

    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

  16. 76 FR 31631 - Heavy Forged Hand Tools From China; Scheduling of Expedited Five-Year Reviews Concerning the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-01

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

  17. 31 CFR 370.40 - Can I be held accountable if my negligence contributes to a forged signature?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...my negligence contributes to a forged signature? 370.40 Section 370.40 Money...my negligence contributes to a forged signature? (a) General. If your failure...contributes to the submission of a forged signature, then you cannot claim that the...

  18. 31 CFR 370.40 - Can I be held accountable if my negligence contributes to a forged signature?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...my negligence contributes to a forged signature? 370.40 Section 370.40 Money...my negligence contributes to a forged signature? (a) General. If your failure...contributes to the submission of a forged signature, then you cannot claim that the...

  19. 31 CFR 370.40 - Can I be held accountable if my negligence contributes to a forged signature?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...my negligence contributes to a forged signature? 370.40 Section 370.40 Money...my negligence contributes to a forged signature? (a) General. If your failure...contributes to the submission of a forged signature, then you cannot claim that the...

  20. 31 CFR 370.40 - Can I be held accountable if my negligence contributes to a forged signature?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...my negligence contributes to a forged signature? 370.40 Section 370.40 Money...my negligence contributes to a forged signature? (a) General. If your failure...contributes to the submission of a forged signature, then you cannot claim that the...

  1. 31 CFR 370.40 - Can I be held accountable if my negligence contributes to a forged signature?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...my negligence contributes to a forged signature? 370.40 Section 370.40 Money...my negligence contributes to a forged signature? (a) General. If your failure...contributes to the submission of a forged signature, then you cannot claim that the...

  2. Troposphere Parameters Derived from Multi-GNSS Data Processing at GFZ

    NASA Astrophysics Data System (ADS)

    Deng, Zhiguo; Uhlemann, Maik; Fritsche, Mathias; Dick, Galina; Wickert, Jens

    2015-04-01

    Usually, the processing of Global Navigation Satellite System (GNSS) observations requires a thorough consideration of atmospheric parameters for precise applications. Accordingly, GPS meteorology has become a tool which uses measurements from ground-based GPS receivers for atmospheric water vapor sounding. Zenith total delay (ZTD) products derived from GNSS complement different other meteorological observing systems. GPS-based ZTD estimates have also been assimilated into numerical weather prediction (NWP) models. In addition to GPS and GLONASS, the new and emerging satellite navigation systems BeiDou and Galileo provide the potential for extended and more precise GNSS applications. Accordingly, the International GNSS Service (IGS) has initiated the Multi-GNSS Experiment (MGEX) to acquire and analyze data from all four constellations. In view of the increased number of actively transmitting satellites, the ZTD parameter estimation will particularly benefit from an improved spatial distribution of observations tracked by the ground-based receivers. In this contribution, we report on the status of our multi-system (GPS, GLONASS, BeiDou, Galileo) data processing at GFZ. Based on data from the MGEX network we produce multi-GNSS solutions including parameter estimates for satellite orbits, clock, station coordinates and site-specific ZTDs. Our presentation focusses on the validation of ZTDs from the multi-GNSS processing and a comparison with single-system ZTD solutions and GFZ's operational near real-time troposphere products.

  3. Proschema: A Matlab application for processing strong motion records and estimating earthquake engineering parameters

    NASA Astrophysics Data System (ADS)

    Segou, M.; Voulgaris, N.

    2010-07-01

    Strong motion records are the original input data for earthquake engineering studies and earthquake resistant building codes. Records originating from both, analogue and modern digital instruments should be subjected to processing in order to derive credible engineering parameters, such as spectral ordinates. A number of processing procedures have been proposed by many researchers through the past few decades; the goal, however, is always the same, identification and removal of noise and performing necessary adjustments related to the operating instrument or the record's quality. A careful inspection of previous processing schemes and the design of several development tests related to major processing steps proved to be helpful in determining the necessary features that the presented software should include. These have been incorporated in a Matlab application in order to produce a reliable and user-friendly interface giving the researcher several options on major processing steps. It is noteworthy that this computer program can be used either as an interactive process tool when individual record processing corresponds to the researcher's needs or, for processing a vast number of records without user supervision and even through a scheduled task.

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

    SciTech Connect

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

    2011-07-15

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

  5. Pod of Ultrasonic Detection of Synthetic Hard Alpha Inclusions in Titanium Aircraft Engine Forgings

    NASA Astrophysics Data System (ADS)

    Thompson, R. B.; Meeker, W. Q.; Brasche, L. J. H.

    2011-06-01

    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, ?3 and ?5, with each size including seeds with nominal nitrogen concentrations of both 3 and 17 wt. %. The FBHs included sizes of ?1, ?3, and ?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 â 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.

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

    PubMed

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

    2012-05-10

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

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

    DOEpatents

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

    1993-01-01

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

  8. Development of functional adsorbent from PU foam waste via radiation induced grafting I: Process parameter standardization

    NASA Astrophysics Data System (ADS)

    Goel, N. K.; Kumar, Virendra; Dubey, K. A.; Bhardwaj, Y. K.; Varshney, L.

    2013-01-01

    Mutual radiation grafting process has been used to covalently link polymer chains of poly(acrylic acid) to polyurethane foam waste using 60Co-gamma radiation source. Various experimental parameters were investigated in order to optimize the grafting process. The grafted samples have been characterized for water-uptake, surface morphology and thermal stability. Grafting extent increased with dose, dose rate and monomer concentration but decreased with increase in density of PU foam. The matrix grafted up to an extent of ˜90% showed uptake capacity of 220 mg/g (0.09 mol of dye/mol of acrylic acid) for a monovalent dye (basic red 29) within 3 h of contact time in a batch process.

  9. Formulation development and process parameter optimization of lipid nanoemulsions using an alginate-protein stabilizer.

    PubMed

    Sen Gupta, Surashree; Ghosh, Mahua

    2015-05-01

    Lipids, especially unstable ones with health beneficiary effects, need to be converted into stable ingredients through nanoencapsulation in a liquid form by development of a nanoemulsion. The primary necessity for synthesis of such nanoemulsions is the development of a formulation for stabilizing the emulsion. Thus parameters to obtain such a stable nanoemulsions were optimized. Hence parameters like temperature, pH and electrolyte concentrations were optimized with respect to different oil:emulsifier ratios (10:1, 15:1, 20:1, 25:1 and 30:1) using sodium alginate, a polysaccharide, as encapsulant and calcium caseinate, a protein, as the emulsifier. Optimization of these process parameters were done based on different physico-chemical techniques like particle-size, zeta-potential, viscosity, lipid content and retention of fatty acid composition by the emulsified oil. Those emulsions which showed maximum resistance to stress and retained minimum particle-size, maximum stability and highest core material retention under stressed conditions were 15:1 and 10:1 emulsion systems. Of the two, 15:1 emulsion system was preferred due to its lower emulsifier requirement. Hence finally the optimized parameters which contributed to the development of the stable emulsions were alkaline pH, temperature of up to 50?ºC and electrolyte concentrations of up to 100 mM. PMID:25892754

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

    NASA Technical Reports Server (NTRS)

    Sankaran, K. K.

    1987-01-01

    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.

  11. Experimental and FE analysis to predict the dimensional changes of workpiece and tool in cold forging

    NASA Astrophysics Data System (ADS)

    Lee, Youngseon; Kwon, Yongnam; Lee, Junghwan; Ishikawa, T.

    2004-06-01

    The dimensional tolerance of spur gear for automobile would be within the range of a several micrometer. Therefore, to manufacture these gears by cold forging, dimensions should be controlled in same range. The dimensional changes by the various forging variables should be analyzed and compensated into the forging tool. CAE would be appropriate for investigating the effects of variables. However, the realistic FE-modeling techniques should be confirmed and used to predict the dimension of forged part in micrometer order. Since the realistic modeling considers elastic characteristics of both workpiece and die and unloading and ejecting stage, 3-dimensional analysis for spur gear may be often facing difficulties in a solving time and convergence. In this study, dimensional changes for cold forged part of spur gear were investigated by experimental and FEM analysis, after FE modeling to get the desirable FEM results had been studied by the closed die upsetting. The dimensional changes of involute curve for spur gear could be analyzed from the FEM results during a whole forging stage. And, they could give an index of modified involute curve of forging tool for improving the gear profile accuracy.

  12. Effect of process parameters on the surface morphology and mechanical performance of silicon structures after deep reactive ion etching (DRIE)

    Microsoft Academic Search

    Kuo-Shen Chen; Arturo A. Ayón; Xin Zhang; S. Mark Spearing

    2002-01-01

    The ability to predict and control the influence of process parameters during silicon etching is vital for the success of most MEMS devices. In the case of deep reactive ion etching (DRIE) of silicon substrates, experimental results indicate that etch performance as well as surface morphology and post-etch mechanical behavior have a strong dependence on processing parameters. In order to

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

    PubMed

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

    2014-07-15

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

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

    PubMed

    Lipps, D M; Sakr, A M

    1994-07-01

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

  15. Sensitivity analysis of a dry-processed Candu fuel pellet's design parameters

    SciTech Connect

    Choi, Hangbok; Ryu, Ho Jin [Korea Atomic Energy Research Institute 1045 Daedeok-daero, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

    2007-07-01

    Sensitivity analysis was carried out in order to investigate the effect of a fuel pellet's design parameters on the performance of a dry-processed Canada deuterium uranium (CANDU) fuel and to suggest the optimum design modifications. Under a normal operating condition, a dry-processed fuel has a higher internal pressure and plastic strain due to a higher fuel centerline temperature when compared with a standard natural uranium CANDU fuel. Under a condition that the fuel bundle dimensions do not change, sensitivity calculations were performed on a fuel's design parameters such as the axial gap, dish depth, gap clearance and plenum volume. The results showed that the internal pressure and plastic strain of the cladding were most effectively reduced if a fuel's element plenum volume was increased. More specifically, the internal pressure and plastic strain of the dry-processed fuel satisfied the design limits of a standard CANDU fuel when the plenum volume was increased by one half a pellet, 0.5 mm{sup 3}/K. (authors)

  16. Effect of process parameters on sidewall damage in deep silicon etch

    NASA Astrophysics Data System (ADS)

    Meng, Lingkuan; Yan, Jiang

    2015-03-01

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

  17. Follow-up of hearing thresholds among forge hammering workers

    SciTech Connect

    Kamal, A.A.; Mikael, R.A.; Faris, R. (Ain Shams Univ., Abbasia, Cairo (Egypt))

    1989-01-01

    Hearing threshold was reexamined in a group of forge hammering workers investigated 8 years ago with consideration of the age effect and of auditory symptoms. Workers were exposed to impact noise that ranged from 112 to 139 dB(A)--at an irregular rate of 20 to 50 drop/minute--and a continuous background noise that ranged from 90 to 94 dB(A). Similar to what was observed 8 years ago, the present permanent threshold shift (PTS) showed a maximum notch at the frequency of 6 kHz and considerable elevations at the frequencies of 0.25-1 kHz. The age-corrected PTS and the postexposure hearing threshold were significantly higher than the corresponding previous values at the frequencies 0.25, 0.5, 1, and 8 kHz only. The rise was more evident at the low than at the high frequencies. Temporary threshold shift (TTS) values were significantly less than those 8 years ago. Contrary to the previous TTS, the present TTS were higher at low than at high frequencies. Although progression of PTS at the frequencies 0.25 and 0.5 kHz was continuous throughout the observed durations of exposure, progression at higher frequencies occurred essentially in the first 10 to 15 years of exposure. Thereafter, it followed a much slower rate. Tinnitus was significantly associated with difficulty in hearing the human voice and with elevation of PTS at all the tested frequencies, while acoustic after-image was significantly associated with increment of PTS at the frequencies 0.25-2 kHz. No relation between PTS and smoking was found. PTS at low frequencies may provide an indication of progression of hearing damage when the sensitivity at 6 and 4 kHz diminishes after prolonged years of exposure. Tinnitus and acoustic after-image are related to the auditory effect of forge hammering noise.

  18. Using neural networks and immune algorithms to find the optimal parameters for an IC wire bonding process

    Microsoft Academic Search

    Chi-hung Su; Hung-zhi Chang

    2008-01-01

    The wire bonding process is the key process in an IC chip-package. It is an urgent problem for IC chip-package industry to improve the wire bonding process capability. In this study, an integration of artificial neural networks (ANN) with artificial immune systems (AIS) is proposed to optimize parameters for an IC wire bonding process. The algorithm of AIS with memory

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

    NASA Technical Reports Server (NTRS)

    Sikora, Paul F; Johnston, James R

    1955-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    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.

  1. Impact of Baryonic Processes on Weak-lensing Cosmology: Power Spectrum, Nonlocal Statistics, and Parameter Bias

    NASA Astrophysics Data System (ADS)

    Osato, Ken; Shirasaki, Masato; Yoshida, Naoki

    2015-06-01

    We study the impact of baryonic physics on cosmological parameter estimation with weak-lensing surveys. We run a set of cosmological hydrodynamics simulations with different galaxy formation models. We then perform ray-tracing simulations through the total matter density field to generate 100 independent convergence maps with a field of view of 25 {{deg }2}, and we use them to examine the ability of the following three lensing statistics as cosmological probes: power spectrum (PS), peak counts, and Minkowski functionals (MFs). For the upcoming wide-field observations, such as the Subaru Hyper Suprime-Cam (HSC) survey with a sky coverage of 1400 {{deg }2}, these three statistics provide tight constraints on the matter density, density fluctuation amplitude, and dark energy equation of state, but parameter bias is induced by baryonic processes such as gas cooling and stellar feedback. When we use PS, peak counts, and MFs, the magnitude of relative bias in the dark energy equation of state parameter w is at a level of, respectively, ? w? 0.017, 0.061, and 0.0011. For the HSC survey, these values are smaller than the statistical errors estimated from Fisher analysis. The bias could be significant when the statistical errors become small in future observations with a much larger survey area. We find that the bias is induced in different directions in the parameter space depending on the statistics employed. While the two-point statistic, i.e., PS, yields robust results against baryonic effects, the overall constraining power is weak compared with peak counts and MFs. On the other hand, using one of peak counts or MFs, or combined analysis with multiple statistics, results in a biased parameter estimate. The bias can be as large as 1? for the HSC survey and will be more significant for upcoming wider-area surveys. We suggest to use an optimized combination so that the baryonic effects on parameter estimation are mitigated. Such a “calibrated” combination can place stringent and robust constraints on cosmological parameters.

  2. Bioreactor process parameter screening utilizing a plackett-burman design for a model monoclonal antibody.

    PubMed

    Agarabi, Cyrus D; Schiel, John E; Lute, Scott C; Chavez, Brittany K; Boyne, Michael T; Brorson, Kurt A; Khan, Mansoor A; Read, Erik K

    2015-06-01

    Consistent high-quality antibody yield is a key goal for cell culture bioprocessing. This endpoint is typically achieved in commercial settings through product and process engineering of bioreactor parameters during development. When the process is complex and not optimized, small changes in composition and control may yield a finished product of less desirable quality. Therefore, changes proposed to currently validated processes usually require justification and are reported to the US FDA for approval. Recently, design-of-experiments-based approaches have been explored to rapidly and efficiently achieve this goal of optimized yield with a better understanding of product and process variables that affect a product's critical quality attributes. Here, we present a laboratory-scale model culture where we apply a Plackett-Burman screening design to parallel cultures to study the main effects of 11 process variables. This exercise allowed us to determine the relative importance of these variables and identify the most important factors to be further optimized in order to control both desirable and undesirable glycan profiles. We found engineering changes relating to culture temperature and nonessential amino acid supplementation significantly impacted glycan profiles associated with fucosylation, ?-galactosylation, and sialylation. All of these are important for monoclonal antibody product quality. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:1919-1928, 2015. PMID:25762022

  3. A first step in prediction of the nanoscale structure of porous silicon from processing parameters.

    PubMed

    Haimi, E; Lindroos, V K; Nowak, R

    2001-06-01

    The present work addresses the formation of porous silicon layers by means of anodic dissolution of p- and p(+)-type boron-doped (100) silicon wafers in 15, 25, and 35 vol% HF-ethanol solutions. The study concerned the dependence of the porous silicon layer growth rate dh/dt on electric current density i as well as on HF concentration. The formation of a porous silicon layer was found to follow a generic linear relationship, in(dh/dt)--in(i), which holds irrespective of the processing conditions. The combination of two equations, experimental and theoretical, derived from Faraday's equation, allowed us to reach conclusions on the relationship between the growth rate dh/dt and the degree of porosity, constituting a first step in prediction of the nanoporous structure of silicon based on processing parameters. This electrochemical approach complements physical models of silicon pore formation. PMID:12914052

  4. Tailoring Selective Laser Melting Process Parameters for NiTi Implants

    NASA Astrophysics Data System (ADS)

    Bormann, Therese; Schumacher, Ralf; Müller, Bert; Mertmann, Matthias; de Wild, Michael

    2012-12-01

    Complex-shaped NiTi constructions become more and more essential for biomedical applications especially for dental or cranio-maxillofacial implants. The additive manufacturing method of selective laser melting allows realizing complex-shaped elements with predefined porosity and three-dimensional micro-architecture directly out of the design data. We demonstrate that the intentional modification of the applied energy during the SLM-process allows tailoring the transformation temperatures of NiTi entities within the entire construction. Differential scanning calorimetry, x-ray diffraction, and metallographic analysis were employed for the thermal and structural characterizations. In particular, the phase transformation temperatures, the related crystallographic phases, and the formed microstructures of SLM constructions were determined for a series of SLM-processing parameters. The SLM-NiTi exhibits pseudoelastic behavior. In this manner, the properties of NiTi implants can be tailored to build smart implants with pre-defined micro-architecture and advanced performance.

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

    PubMed

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

    2014-10-01

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

  6. Effect of Processing Parameters on the Mechanical Properties of Interstitial Free Steel Subjected to Friction Stir Processing

    NASA Astrophysics Data System (ADS)

    Chabok, A.; Dehghani, K.

    2013-05-01

    In the present work, the effect of friction stir processing parameters on the mechanical properties of an interstitial free steel was studied. Four rotating speeds (800, 1250, 1600, 2000 rpm) and two traverse speeds (31.5 and 63 mm/min) were employed. On both sides of specimens, a nanograin layer with the thickness and nanograins of 150 ?m and 50-100 nm were formed, respectively. For the specimen processed at rotating speed of 1600 rpm and the traverse speed of 31.5 mm/min, the maximum strength was achieved, which was about 80% increase in the strength comparing to that of base material. For constant traverse speed, the increase in the rotation speed from 800 to 1600 rpm led to a decrease in uniform and total elongation of friction stir processed samples. By contrast, when the rotating speed exceeded 1600 rpm, the uniform and total elongation was increased again, while there was a drop in strength. The results of microhardness indicate more than threefold increase in the hardness of the stirred zone comparing to that of base material.

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

    PubMed

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

    2012-02-01

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

  8. Influence of the process parameters on the characteristics of starch based hot stage extrudates.

    PubMed

    Henrist, D; Remon, J P

    1999-10-28

    The influence of the process parameters on the characteristics of matrix formulations produced by means of hot stage extrusion was investigated using three experimental designs. The first one was designed to evaluate the importance of the screw speed (150-450 rpm) and the feed rate (2-12 kg/h), while the second and the third were designed to study the importance of the temperature profile (60-120 degrees C). The extrudates were produced with a laboratory twin screw extruder equipped with a 3-mm cylindrical die. The formulations consisted of 53% corn starch, 15% sorbitol, 2% glyceryl monostearate and 30% theophylline monohydrate as the model drug. The extrudates were characterized by Karl-Fischer titration, Hg-porosimetry, four-point bending and dissolution testing. From the first design it was concluded that the screw speed and feed rate hardly affected the water content of the extrudates, but that there was a clear influence on the extrudate radius, porosity, mechanical strength and dissolution behaviour. High screw speed-high feed rate processes in comparison with low screw speed-low feed rate processes caused an increase in extrudate radius and porosity and a decrease in mechanical strength and drug release rate from the matrix. It was clear that the contribution of the feed rate was higher than that of the screw speed. Expansion, promoted under certain extrusion conditions, could explain the obtained results. The second and third design revealed that only the maximum barrel temperature and not the whole temperature profile was responsible for the temperature effects on the extrudate characteristics. It was concluded that the maximum barrel temperature was the most critical parameter of the hot stage extrusion process. PMID:10518681

  9. Constraining sources, transport pathways and process parameters on various scales by atmospheric Lagrangian inversions

    NASA Astrophysics Data System (ADS)

    von Hobe, Marc; Konopka, Paul; Hoffmann, Lars; Griessbach, Sabine; Sumi?ska-Ebersoldt, Olga; Vernier, Jean-Paul; Plöger, Felix; Tao, Mengchu; Müller, Rolf

    2015-04-01

    Inverse methods have become widely used tools to infer sources and sinks of atmospheric constituents based on observations. Inversion techniques can also help to better constrain input and process parameters and thus improve the underlying models. While the majority of today's inverse model frameworks use the Eulerian concept of transport, the capability of Lagrangian inversion to infer emissions of even ill constrained sources has been demonstrated (e.g. Stohl et al., 2011). We will discuss Lagrangian inverse modelling as a powerful tool to solve problems on a wide range of scales in terms of spatial and temporal extent as well as complexity. First, two distinct applications on different scales will be presented: i) the retrieval of reaction rates that govern the chlorine catalyzed ozone destruction in the polar winter along individual trajectories connecting airborne observations in the Arctic in 2010, and ii) the derivation of emission altitudes and transport pathways of sulfate aerosol from the 2011 eruption of the Nabro volcano using CALIPSO satellite observations. Second, the potential and requirements for applications at even higher complexity, e.g. simultaneously retrieval of source, sink and process parameters on a global scale, will be explored. Stohl, A., et al. 2011. Atmospheric Chemistry and Physics 11, 4333-4351.

  10. Effect of process parameters on stress development in two-dimensional oxidation

    NASA Astrophysics Data System (ADS)

    Hu, S. M.

    1988-07-01

    A simplified viscoelastic analysis has been made of the stress evolution during two-dimensional (2D) oxidation of silicon substrates, with the objective of learning the effect of process parameters such as temperature and steam pressure. A cylindrical silicon surface was chosen for simplicity of analysis, and yet it still has most of the essential elements pertinent to practical problems such as, e.g., the oxidation of trench corners in silicon integrated circuits. With correlations between the viscosity and the hydroxyl content of SiO2, and between the hydroxyl content and the steam pressure, the analysis shows that stress reduction can be achieved by carrying out oxidation at high steam pressures. However, stresses remain rather high if the oxidation temperature is as low as 800 °C. For a linear-parabolic oxidation kinetics, both the oxide and the substrate stresses do not increase indefinitely with the increase of oxide thickness, but reach their respective peaks at oxide thicknesses that are dependent on process parameters. The present results should be useful in serving as guidelines in the selection of 2D oxidation conditions. The accuracy of a previous 2D oxidation model based on the viscous flow of an incompressible fluid has also been assessed with reference to the viscoelastic model. The incompressible-fluid model is found to be quite accurate at high temperatures ?900 °C.

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

    PubMed Central

    Heidari, Ali; Forouzan, Mohammad R.

    2012-01-01

    Chatter has been recognized as major restriction for the increase in productivity of cold rolling processes, limiting the rolling speed for thin steel strips. It is shown that chatter has close relation with rolling conditions. So the main aim of this paper is to attain the optimum set points of rolling to achieve maximum rolling speed, preventing chatter to occur. Two combination methods were used for optimization. First method is done in four steps: providing a simulation program for chatter analysis, preparing data from simulation program based on central composite design of experiment, developing a statistical model to relate system tendency to chatter and rolling parameters by response surface methodology, and finally optimizing the process by genetic algorithm. Second method has analogous stages. But central composite design of experiment is replaced by Taguchi method and response surface methodology is replaced by neural network method. Also a study on the influence of the rolling parameters on system stability has been carried out. By using these combination methods, new set points were determined and significant improvement achieved in rolling speed. PMID:25685398

  12. Structural parameters of Pr3MgNi14 during hydrogen absorption-desorption process.

    PubMed

    Iwase, Kenji; Terashita, Naoyoshi; Mori, Kazuhiro; Ishigaki, Toru

    2012-11-01

    Structural parameters of Pr(3)MgNi(14) after a cyclic hydrogen absorption-desorption process were investigated by X-ray diffraction. Pr(3)MgNi(14) consisted of two phases: 80% Gd(2)Co(7)-type structure and 20% PuNi(3)-type structure. The pressure-composition (P-C) isotherm of Pr(3)MgNi(14) indicates a maximum hydrogen capacity of 1.12 H/M (1.61 mass %) at 298 K. The cyclic property of Pr(3)MgNi(14) up to 1000 cycles was measured at 313 K. The retention rate of the sample was 87.5% at 1000 cycles, which compares favorably with that of LaNi(5). After 1000 cycles, the expansions of lattice parameters a and c and the lengths along the c-axes of the PrNi(5) and PrMgNi(4) cells of the Gd(2)Co(7)-type structures were 0.20%, 1.26%, 0.47%, and 3.68%, respectively. The metal sublattice expanded anisotropically after the cyclic test. The isotropic and anisotropic lattice strains can be refined by Rietveld analysis. The anisotropic and isotropic lattice strains were almost saturated at the first activation process and reached values of 0.2% and 0.1%, respectively, after 1000 cycles. These values are smaller by 1 order of magnitude than those of LaNi(5). PMID:23075131

  13. Optimization of HTST process parameters for production of ready-to-eat potato-soy snack.

    PubMed

    Nath, A; Chattopadhyay, P K; Majumdar, G C

    2012-08-01

    Ready-to-eat (RTE) potato-soy snacks were developed using high temperature short time (HTST) air puffing process and the process was found to be very useful for production of highly porous and light texture snack. The process parameters considered viz. puffing temperature (185-255 °C) and puffing time (20-60 s) with constant initial moisture content of 36.74% and air velocity of 3.99 m.s(-1) for potato-soy blend with varying soy flour content from 5% to 25% were investigated using response surface methodology following central composite rotatable design (CCRD). The optimum product in terms of minimum moisture content (11.03% db), maximum expansion ratio (3.71), minimum hardness (2,749.4 g), minimum ascorbic acid loss (9.24% db) and maximum overall acceptability (7.35) were obtained with 10.0% soy flour blend in potato flour at the process conditions of puffing temperature (231.0 °C) and puffing time (25.0 s). PMID:23904651

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

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    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.

  15. A Ceramic Waste Heat Recovery System on a Rotary Forge Furnace: An Installation and Operating History

    E-print Network

    Young, S. B.; Campbell, T. E.; Worstell, T. M.

    1981-01-01

    In the fall of 1980, the Reed Rock Bit Company (Houston, Texas) placed a Hague International high temperature energy conservation system on a rotary hearth furnace used to heat steel billets for forging. The energy conservation system includes a...

  16. 75 FR 70689 - Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum-Greenwood Forge Division; Currently...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-18

    ...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...

  17. Influence of process parameters on properties of Nanostructured Lipid Carriers (NLC) formulation.

    PubMed

    Laso?, Elwira; Sikora, El?bieta; Ogonowski, Jan

    2013-01-01

    Nanostructured lipid carriers (NLC) are stable colloidal formulations with notable advantages for drug delivery systems. Thanks to their physicochemical stability, biocompatibility, biodegradability and controlled drug release, they have received increasing attention for the last several years. The aim of the study was to prepare and characterize nanostructured lipid carriers (NLC). Both, the effect of the process parameters and the effect of the preemulsion composition on the NLC properties were investigated. In the work, different type of surfactants (i.e. decyl glucoside, Poloxamer188, Tween 80, sodium cholate) and their combinations were used to stabilize NLC dispersions. Moreover, several kinds of solid lipids (modified beeswax, gliceryl behenate, cetyl palmitate and berry wax) and liquid lipids (caprilic/capric triglyceride and decyl oleate) were applied. An ultrasonication method using a probe type sonicator was used to obtain NLC, and the time and energy of the process were modified throuhout. The physicochemical properties of the formulations, such as particle size, size distribution, polidispersity index were studied using the dynamic light scattering (DLS) method. The electrophoretic mobility of obtained particles was also measured, using the Zetasizer Nano ZS Malvern Instrument based on the Laser Doppler Velocimetry (LDV) technique. Knowing the value of electrophoretic mobility of particles for given conditions, the zeta potential was determined. The obtained results showed that the process parameters and the composition of the preemulsion had significant impact on the nanoparticles structure. The optimal formulations size ranged between 60 and 80 nm, and the value of their zeta potential was up to -30mV. The stability of these systems was further confirmed by macroscopic observation. PMID:24432330

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

    PubMed

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

    2013-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    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.

  20. 232 IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 41. NO. I , JANUARY 1993 Parameter Estimation and Extraction of Helicopter

    E-print Network

    Feder, Meir

    232 IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 41. NO. I , JANUARY 1993 Parameter Estimation as an autoregressive (AR) process. The suggested al- gorithms can also be used for other harmonic signals. Experi the deviation from strict periodicity. The wide- band signal is modeled as a Gaussian random process

  1. Self-bias Dependence on Process Parameters in Asymmetric Cylindrical Coaxial Capacitively Coupled Plasma

    E-print Network

    Upadhyay, J; Popovi?, S; Valente-Feliciano, A -M; Phillips, L; Vuškovi?, L

    2015-01-01

    An rf coaxial capacitively coupled Ar/Cl2 plasma is applied to processing the inner wall of superconducting radio frequency cavities. A dc self-bias potential is established across the inner electrode sheath due to the surface area difference between inner and outer electrodes of the coaxial plasma. The self-bias potential measurement is used as an indication of the plasma sheath voltage asymmetry. The understanding of the asymmetry in sheath voltage distribution in coaxial plasma is important for the modification of the inner surfaces of three dimensional objects. The plasma sheath voltages were tailored to process the outer wall by providing an additional dc current to the inner electrode with the help of an external dc power supply. The dc self-bias potential is measured for different diameter electrodes and its variation on process parameters such as gas pressure, rf power and percentage of chlorine in the Ar/Cl2 gas mixture is studied. The dc current needed to overcome the self-bias potential to make it ...

  2. Optimizing the equal channel angular pressing process (ECAP) operation parameters to produce bulk nanostructure materials

    NASA Astrophysics Data System (ADS)

    Abushgair, K.

    2015-03-01

    In this work we were interested in doing simulation using finite elements analysis (FEA) to study the equal channel angular pressing process (ECAP), which is currently one of the most popular methods of severe plastic deformation Processes (SPD). for fabricating Ultra-Fine Grained (UFG) materials, because it allows very high strains to be imposed leading to extreme work hardening and microstructural refinement. The main object of this study is to establish the influence of main parameters which effect ECAP process which are magnitude of the die angle and the friction coefficient. The angle studied between (90-135°) degree, and magnitude of the friction coefficient ? between (0.12-0.6), and number of pass. The samples were made from aluminum alloy at room temperature with (15X 15) mm cross section and 150 mm length. The simulation result shows that normal elastic strain, shears elastic strain, and max. shear elastic strain increased, when changing the angle from 90° to 100°. and decrease between the angle 110° to 135°. Also the total deformation increased when we change die angle from 90° to 135°. By studding the friction effect on the die and sample we noted that increasing the friction coefficient from 0.12 to 0.6, normal elastic strain, and shear elastic strain increased and increasing the friction coefficient from 0.1 to 0.6 decrease the normal and shear stress.

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

    NASA Technical Reports Server (NTRS)

    Rice, R. W.

    1972-01-01

    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.-

  4. Scalable Hyper-parameter Estimation for Gaussian Process Based Time Series Analysis

    SciTech Connect

    Chandola, Varun [ORNL; Vatsavai, Raju [ORNL

    2010-01-01

    Gaussian process (GP) is increasingly becoming popular as a kernel machine learning tool for non-parametric data analysis. Recently, GP has been applied to model non-linear dependencies in time series data. GP based analysis can be used to solve problems of time series prediction, forecasting, missing data imputation, change point detection, anomaly detection, etc. But the use of GP to handle massive scientific time series data sets has been limited, owing to its expensive computational complexity. The primary bottleneck is the handling of the covariance matrix whose size is quadratic in the length of the time series. In this paper we propose a scalable method that exploit the special structure of the covariance matrix for hyper-parameter estimation in GP based learning. The proposed method allows estimation of hyper parameters associated with GP in quadratic time, which is an order of magnitude improvement over standard methods with cubic complexity. Moreover, the proposed method does not require explicit computation of the covariance matrix and hence has memory requirement linear to the length of the time series as opposed to the quadratic memory requirement of standard methods. To further improve the computational complexity of the proposed method, we provide a parallel version to concurrently estimate the log likelihood for a set of time series which is the key step in the hyper-parameter estimation. Performance results on a multi-core system show that our proposed method provides significant speedups as high as 1000, even when running in serial mode, while maintaining a small memory footprint. The parallel version exploits the natural parallelization potential of the serial algorithm and is shown to perform significantly better than the serial faster algorithm, with speedups as high as 10.

  5. The effect of processing parameters on plasma sprayed beryllium for fusion applications

    SciTech Connect

    Castro, R.G.; Stanek, P.W.; Jacobson, L.A. [Los Alamos National Lab., NM (United States); Cowgill, D.F. [Sandia National Labs., Livermore, CA (United States); Snead, L.L. [Oak Ridge National Lab., TN (United States)

    1993-10-01

    Plasma spraying is being investigated as a potential coating technique for applying thin (0.1--5mm) layers of beryllium on plasma facing surfaces of blanket modules in ITER and also as an in-situ repair technique for repairing eroded beryllium surfaces in high heat flux divertor regions. High density spray deposits (>98% of theoretical density) of beryllium will be required in order to maximize the thermal conductivity of the beryllium coatings. A preliminary investigation was done to determine the effect of various processing parameters (particle size, particle morphology, secondary gas additions and reduced chamber pressure) on the as-deposited density of beryllium. The deposits were made using spherical beryllium feedstock powder which was produced by centrifugal atomization at Los Alamos National Laboratory (LANL). Improvements in the as-deposited densities and deposit efficiencies of the beryllium spray deposits will be discussed along with the corresponding thermal conductivity and outgassing behavior of these deposits.

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

    SciTech Connect

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

    2000-01-04

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2004-03-01

    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 NH4NO3 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 NH4NO3, 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).

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

    PubMed

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

    2015-03-01

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

  9. Optimization of processing parameters for the synthesis of tungsten carbide (WC) nanoparticles through solvo thermal route

    NASA Astrophysics Data System (ADS)

    Kumar, Akshay; Singh, K.; Pandey, O. P.

    2010-07-01

    In order to manufacture cemented tungsten carbide nanomaterials efforts are being made to synthesize nano-WC powders by different techniques. The present work is an attempt to synthesize WC nanoparticles by thermo-chemical route where WO 3 was reduced to nano-WC. During experimentation the reaction parameters were varied to optimize the processing variables for the formation of tungsten carbide (WC) nanoparticles. The reaction time 20 h for 36 ml acetone as a carbon source gives the maximum yield of WC. Phase identification of the product phase(s) was done by X-ray diffraction and transmission electron microscope. Differential thermal analyzer and thermal gravimetric analysis were also done to study phase transformation and stability of the product phases.

  10. Parameter regionalization for a process-oriented distributed model dedicated to flash floods

    NASA Astrophysics Data System (ADS)

    Garambois, P. A.; Roux, H.; Larnier, K.; Labat, D.; Dartus, D.

    2015-06-01

    This contribution is one of the first studies about the regionalization of parameter sets for a rainfall-runoff model process-oriented and dedicated to flash floods. MARINE model performances are tested on a large database of 117 flash floods occurred during the last two decades in the French Mediterranean region. Given the scarcity of flash flood data, the dataset used in this study represents a large sample of hydrology and landscapes from Pyrenean, Mediterranean, Cévennes-Vivarais and Provence regions. Spatial proximity and similarity approaches with several combinations of descriptors are tested. Encouraging results are obtained with two similarity approaches based on physiographic descriptors with two and three donor catchments. There is only a small decrease of performance of 10% from cal/val to regionalization for these two methods. For 13 catchments out of 16 there is at least one flood event simulated with rather good performance. This study highlights the importance of hydrological information that is available in calibration events for a gauged catchment and from donor catchment(s) for regionalization. Moreover it is found that regionalization is easier for catchments with an apparently more regular behaviour. The most sensitive parameter of MARINE model, CZ, controlling soil volume and water balance, is rather well constrained by the two similarity approaches thanks to bedrock descriptors.

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

    NASA Technical Reports Server (NTRS)

    Pindera, Marek-Jerzy; Salzar, Robert S.

    1996-01-01

    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.

  12. Experimental design for optimal parameter estimation of an enzyme kinetic process based on the analysis of the Fisher information matrix.

    PubMed

    Oliver Lindner, Patrick Felix; Hitzmann, Bernd

    2006-01-01

    The investigation of enzyme kinetics is increasingly important, especially for finding active substances and understanding intracellular behaviors. Therefore, the determination of an enzyme's kinetic parameters is crucial. For this a systematic experimental design procedure is necessary to avoid wasting time and resources. The parameter estimation error of a Michaelis-Menten enzyme kinetic process is analysed analytically to reduce the search area as well as numerically to specify the optimum for parameter estimation. From analytical analysis of the Fisher information matrix the fact is obtained, that an enzyme feed will not improve the estimation process, but substrate feeding is favorable with small volume flow. Unconstrained and constrained process conditions are considered. If substrate fed-batch process design is used instead of pure batch experiments the improvements of the Cramer-Rao lower bound of the variance of parameter estimation error reduces to 82% for mu(max) and to 60% for K(m) of the batch values in average. PMID:16039672

  13. Analysis of roughness parameters to specify superhydrophobic antireflective boehmite films made by the sol–gel process

    Microsoft Academic Search

    Xiaoxue Zhang; Mikael Järn; Jouko Peltonen; Viljami Pore; Tommi Vuorinen; Erkki Levänen; Tapio Mäntylä

    2008-01-01

    Superhydrophobic antireflective boehmite films with different topographies were made by the sol–gel process with variation of heat-treatment temperatures and film thicknesses. A set of roughness parameters was determined from atomic force microscope (AFM) to relate the superhydrophobic and antireflective properties to the surface topographies. The results demonstrate the power of the roughness parameters to identify such superhydrophobic antireflective films.

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

    Microsoft Academic Search

    Wen-Ruey Chang

    2000-01-01

    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

  15. The effect of filtering processes on surface roughness parameters and their correlation with the measured friction, Part I: quarry tiles

    Microsoft Academic Search

    Wen-Ruey Chang; S. Matz

    2000-01-01

    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 surface roughness measurement affects the values of surface parameters and, therefore, affects surface representations. The effect of filter selection on the surface parameters and their correlation with the measured friction was investigated in this

  16. Experimental design for optimal parameter estimation of an enzyme kinetic process based on the analysis of the Fisher information matrix

    Microsoft Academic Search

    Patrick Felix Oliver Lindner; Bernd Hitzmann

    2006-01-01

    The investigation of enzyme kinetics is increasingly important, especially for finding active substances and understanding intracellular behaviors. Therefore, the determination of an enzyme's kinetic parameters is crucial. For this a systematic experimental design procedure is necessary to avoid wasting time and resources. The parameter estimation error of a Michaelis–Menten enzyme kinetic process is analysed analytically to reduce the search area

  17. Development of empirical model for different process parameters during rotary electrical discharge machining of copper–steel (EN8) system

    Microsoft Academic Search

    K. D. Chattopadhyay; S. Verma; P. S. Satsangi; P. C. Sharma

    2009-01-01

    The present work investigates the machining characteristics of EN-8 steel with copper as a tool electrode during rotary electrical discharge machining process. The empirical models for prediction of output parameters have been developed using linear regression analysis by applying logarithmic data transformation of non-linear equation. Three independent input parameters of the model viz. peak current, pulse on time and rotational

  18. A study of the process parameters for yttria-stabilized zirconia electrolyte films prepared by screen-printing

    Microsoft Academic Search

    Yaohui Zhang; Xiqiang Huang; Zhe Lu; Zhiguo Liu; Xiaodong Ge; Jiahuan Xu; Xianshuang Xin; Xueqing Sha; Wenhui Su

    2006-01-01

    Screen-printing technology was developed to fabricate gas-tight yttria-stabilized zirconia (YSZ) electrolyte films on porous NiO–YSZ anode substrates for use in solid oxide fuel cells (SOFCs). Several key process parameters such as the starting YSZ powder, printing ink composition, printing time and sintering temperature were studied and reported in detail. SEM results revealed that the selected process parameters exerted obvious influences

  19. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

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

    PubMed

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

    2014-04-10

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

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

    SciTech Connect

    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

    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.

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

    PubMed

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

    2014-02-01

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

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

    NASA Astrophysics Data System (ADS)

    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

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    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.

  6. Numerical simulation of multi-mini-pot pouring process of a 13-ton steel ingot

    NASA Astrophysics Data System (ADS)

    Li, Jun; Ge, Honghao; Wang, Bin; Wu, Menghuai; Li, Jianguo

    2015-06-01

    Heavy ingots up to several hundred tons for power plant forgings exhibit large scale grain size and morphology differences, which are harmful to the design of forging parameters, and severe macrosegregation, which could not be eliminated during the subsequent forging and heat treatment processing. To cast these ingots with more homogeneity, a multi-mini-pot (MMP) poring technique is proposed, in which liquid metal is poured by multi-mini-pot (MMP) with intermission between each pot and solidification occurs step by step. In this paper, we are focus on the prediction of macrosegregation in MMP pouring process. A three-phase model is employed to study the MMP pouring process for a 13-ton heavy ingot. The main features of this three-phases model in such a heavy ingot can be quantitatively modelled: growth of columnar dendrite trunks; nucleation, growth and sedimentation of equiaxed crystals; thermosolutal convection of the melt; solute transport by both convection and crystal sedimentation; and the columnar-to-equiaxed transition (CET). The results shown that the MMP pouring technique tend to decrease the macrosegregation significantly by compared with the conventional method.

  7. Effect of processing parameters on the magnetic properties of strontium ferrite sintered magnets using Taguchi orthogonal array design

    NASA Astrophysics Data System (ADS)

    Sharma, Puneet; Verma, Amitabh; Sidhu, R. K.; Pandey, O. P.

    2006-12-01

    In the present paper, influence of various processing parameters on the magnetic properties of strontium ferrite sintered permanent magnets has been studied. Taguchi L-9 orthogonal array design is used for analyzing the effect of Fe 2O 3/SrO mole ratio, milling time, calcination temperature and sintering temperature on the magnetic properties. The individual effect of each parameter on the magnetic properties in correlation with microstructure and phase formation is discussed. It is found that Taguchi design is adequate to understand the effect of processing parameter in the limited number of experiments.

  8. Chronic alcohol exposure negatively impacts the physiological and molecular parameters of the renal biotin reabsorption process.

    PubMed

    Subramanian, Veedamali S; Subramanya, Sandeep B; Said, Hamid M

    2011-03-01

    Normal body homeostasis of biotin is critically dependent on its renal recovery by kidney proximal tubular epithelial cells, a process that is mediated by the sodium-dependent multivitamin transporter (SMVT; a product of the SLC5A6 gene). Chronic ethanol consumption interferes with the renal reabsorption process of a variety of nutrients, including water-soluble vitamins. To date, however, there is nothing known about the effect of chronic alcohol feeding on physiological and molecular parameters of the renal biotin reabsorption process. We addressed these issues using rats and transgenic mice carrying the human SLC5A6 (P1P2) 5'-regulatory region as an in vivo model systems of alcohol exposure, and cultured human renal proximal tubular epithelial HK-2 cells chronically exposed to alcohol as an in vitro model of alcohol exposure. The [(3)H]biotin uptake results showed that chronic ethanol feeding in rats leads to a significant inhibition in carrier-mediated biotin transport across both renal brush border and basolateral membrane domains. This inhibition was associated with a marked reduction in the level of expression of SMVT protein, mRNA, and heterogenous nuclear RNA (hnRNA). Furthermore, studies with transgenic mice carrying the SLC5A6 5'-regulatory region showed that chronic alcohol feeding leads to a significant decrease in promoter activity. Studies with HK-2 cells chronically exposed to alcohol again showed a marked reduction in carrier-mediated biotin uptake, which was associated with a significant reduction in promoter activity of the human SLC5A6 5'-regulatory region. These findings demonstrate for the first time that chronic ethanol feeding inhibits renal biotin transport and that this effect is, at least in part, being exerted at the transcriptional level. PMID:21209005

  9. Assessment Of Motion Parameters Of A Moving Object Through Image Processing

    NASA Astrophysics Data System (ADS)

    Wolf, D.; Ciccotelli, J.; Horn, O.; Husson, R.

    1989-04-01

    On this paper, we set out a system which deals with the extraction of speed and position vectors of a target in an image sequence with standard technological elements within a minimum time. The application field, we want to deal with is the one of robotics and the automatic tracking of vehicules. The strategy which is used to build such a system requires three complementary techniques : optics, electronics and data processing of which respective functions are filtering, the operation of difference and the calculation of dynamic parameters. The speed of optical treatments combined with electronics leads to a real time isotrope edge detector, it's space cut-off frequency being adjustable. Based on the unsharp masking technique this extractor carries out the difference between a sharp image and the same image which has been previously defocussed. Therefore this modified image is quantized according to statistical criteria. This process optimizes the number of quantization levels useful for a given S.N.R. in order to reduce the size of the digital image. It means to reduce further calculation time. At last a fast template matching algorithm is carried out from partial correlation functions. These functions are calculated for each level of quantization and modified by a relative weighting. Lastly, a simple numerical calculation assesses the speed and position of the target. The performances of this process allow us to reach calculation times below 200 ms on a standard 3 MIPS processor when dealing with most of the tracking problems and in presence of "noise" as well. For instance, this device can either measure the automatic tracking of an all roads vehicule in a field, or the automatic hold of an object moving on an assembly line thanks to a robot.

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

    SciTech Connect

    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

    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.

  11. Advances in distributed parameter approach to the dynamics and control of activated sludge processes for wastewater treatment.

    PubMed

    Lee, T T; Wang, F Y; Newell, R B

    2006-03-01

    This paper presents a review of modelling and control of biological nutrient removal (BNR)-activated sludge processes for wastewater treatment using distributed parameter models described by partial differential equations (PDE). Numerical methods for solution to the BNR-activated sludge process dynamics are reviewed and these include method of lines, global orthogonal collocation and orthogonal collocation on finite elements. Fundamental techniques and conceptual advances of the distributed parameter approach to the dynamics and control of activated sludge processes are briefly described. A critical analysis on the advantages of the distributed parameter approach over the conventional modelling strategy in this paper shows that the activated sludge process is more adequately described by the former and the method is recommended for application to the wastewater industry. PMID:16458947

  12. Effects of process parameters on pattern-edge roughness of chemically amplified resists

    NASA Astrophysics Data System (ADS)

    Koh, Hui Peng; Lin, Qunying; Hu, Xiao; Chan, Lap H.

    2000-06-01

    Line-edge roughness (LER) has been identified to cause variation in critical dimension that affects the fidelity of pattern transfer and results in greater variation in device electrical performance. In present study, the effects of aerial image quality and resist processing parameters on the severity of LER are studied. Two chemically amplified resists (CARs) with both acetal and ESCAP-type protection groups are tested and compared. It is found that the image-log-slope (ILS) at pattern edge and the resist contrast are the two major factors affecting the magnitude of LER. The ILS is alterable by pattern density, pattern width, defocus conditions and the application of PSM. On the other hand, the shape and slope of the contrast curve are dependent on both soft bake and post-exposure bake temperature. Due to the finite contrast of resist, solubility change occurs across some dose interval. This corresponds to a boundary width at the aerial image that dictates the transition zone across the pattern edge. As the boundary width region is associated with higher roughness film, smaller boundary width could be translated to better LER. Nevertheless, a three-step development model is used to explain the dependence of LER on pattern density. Basically the discrepancy is due to differential progress of the development front at different ILS when developing time is fixed. In addition, changing the shape and slope of the resist contrast curve through different processing routes could directly modify the boundary width and therefore the LER. The attributes causing different LER performances of the two resists are also discussed.

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

    PubMed

    Figueroa, Carlos E; Bose, Sonali

    2013-11-01

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

  14. Microstructural characteristics of aluminum 2024 by cold working in the SIMA process

    Microsoft Academic Search

    Jae Chan Choi; Hyung Jin Park

    1998-01-01

    The SSF (semi-solid forging) is compound forging technology to manufacture near net shaped parts. For SSF, it is necessarily required to prepare a workpiece with a globular microstructure. Amongst several processes to obtain a globular microstructure, the SIMA (strain induced melt activated) process is very simple and advantageous with respect to equipment. This paper presents the influence of effective strain

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

    PubMed

    Doucha, J; Lívanský, K

    2008-12-01

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

  16. Process Parameters in Resistance Projection Welding for Optical Transmission Device Package

    NASA Astrophysics Data System (ADS)

    Huang, Her-Yueh; Tseng, Kuang-Hung

    2011-03-01

    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.

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

    PubMed

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

    2014-09-01

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

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

    DOEpatents

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

    1998-01-01

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

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

    PubMed

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

    2012-06-01

    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

  20. Prolonged laser ablation effects of YBCO ceramic targets during thin film deposition: Influence of processing parameters

    SciTech Connect

    Tomov, R.; Tsaneva, V.; Tsanev, V.; Ouzounov, D. [Institute of Electronics, Sofia (Bulgaria)

    1996-12-01

    Cumulative laser irradiation during high-T{sub c} superconducting thin film pulsed laser deposition (PLD) may have a detrimental effect on film characteristics. Initial decrease of deposition rate and gradual shift of the center of the deposited material spot towards the incoming laser beam were registered on cold glass substrates. Their absorbance was used for evaluation of the film thickness distribution over the substrate area. At the initial stage, two components of the spot could be distinguished along its short axis: central ({approximately}cos{sup n}{theta}, n>>1) and peripherial ({approximately}cos{theta}), while with cumulative irradiation the thickness followed an overall cos{sup m}{theta} (mprocessing parameters - laser fluence and oxygen environment. The results can be consistently explained suggesting the existence of an additional effective ablation threshold imposed by the modified surface relief.

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2000-07-01

    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.

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

    SciTech Connect

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

    1994-05-01

    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.

  4. Powder metallurgy processing of high strength turbine disk alloys

    NASA Technical Reports Server (NTRS)

    Evans, D. J.

    1976-01-01

    Using vacuum-atomized AF2-1DA and Mar-M432 powders, full-scale gas turbine engine disks were fabricated by hot isostatically pressing (HIP) billets which were then isothermally forged using the Pratt & Whitney Aircraft GATORIZING forging process. While a sound forging was produced in the AF2-1DA, a container leak had occurred in the Mar-M432 billet during HIP. This resulted in billet cracking during forging. In-process control procedures were developed to identify such leaks. The AF2-1DA forging was heat treated and metallographic and mechanical property evaluation was performed. Mechanical properties exceeded those of Astroloy, one of the highest temperature capability turbine disk alloys presently used.

  5. Modelling the correlation between cutting and process parameters in high-speed machining of Inconel 718 alloy using an artificial neural network

    Microsoft Academic Search

    E.O. Ezugwu; D. A. Fadare; J. Bonney; R. B. Da Silva; W. F. Sales

    2005-01-01

    An artificial neural network (ANN) model was developed for the analysis and prediction of the relationship between cutting and process parameters during high-speed turning of nickel-based, Inconel 718, alloy. The input parameters of the ANN model are the cutting parameters: speed, feed rate, depth of cut, cutting time, and coolant pressure. The output parameters of the model are seven process

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

    Microsoft Academic Search

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

    2005-01-01

    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

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

    Microsoft Academic Search

    Shuokr Qarani Aziz; Hamidi Abdul Aziz; Mohd Suffian Yusoff

    2011-01-01

    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

  8. Do fattening process and biological parameters affect the accumulation of metals in Atlantic bluefin tuna?

    PubMed

    Milatou, Niki; Dassenakis, Manos; Megalofonou, Persefoni

    2015-07-01

    The objective of this study was to determine the current levels of heavy metals and trace elements in Atlantic bluefin tuna muscle tissues and how they are influenced by the fattening process and various life history parameters to ascertain whether the concentrations in muscle tissue exceed the maximum levels defined by the European Commission Decision and to evaluate the health risk posed by fish consumption. A total of 20 bluefin tuna reared in sea cages, ranging from 160 to 295 cm in length and from 80 to 540 kg in weight, were sampled from a bluefin tuna farm in the Ionian Sea. The condition factor K of each specimen was calculated and their age was estimated. Heavy metal and trace element (Hg, Zn, Fe and Cu) contents were determined in muscle tissue using cold vapour atomic absorption spectrometry and flame and graphite furnace atomic absorption spectrometry. The total Hg concentrations ranged from 0.28 to 1.28 mg kg(-1) w/w, Zn from 5.81 to 76.37 mg kg(-1) w/w, Fe from 12.14 to 39.58 mg kg(-1) w/w, and Cu from 0.36 to 0.94 mg kg(-1) w/w. Only 5% of the muscle samples of tuna contained Hg above the maximum level laid down by the European Commission Decision. Moreover, 15% of the muscle samples contained Zn above the maximum level, while Fe and Cu concentrations were within the acceptable tolerable guideline values. The reared bluefin tuna had lower concentrations of Hg than the wild ones from the Mediterranean Sea. Hg and Fe concentrations showed a positive relationship with size and age of bluefin tuna, whereas negative relationships were found for the concentrations of Zn and Cu. The estimated dietary intake values of the analysed metals were mostly below the derived guidelines. PMID:25906290

  9. Development of forging and heat treating practices for AMS 5737 for use at liquid helium temperatures

    SciTech Connect

    Dalder, E.N.C. (Lawrence Livermore National Lab., CA); Greenlee, M.

    1981-08-10

    To achieve a combination of high yield-strength (sigma y), plane-strain fracture-toughness (K/sub IC/) and resistance to galling when turned against austenitic stainless steels in highly-loaded threaded turnbuckles in the M.F.T.F.-B (Mirror Fusion Test Facility), AMS 5737 (Fe-15Cr-25Ni-1Mo-V-Ti-Al-B), a heat-treatable Fe-base superalloy that is slightly-ferromagnetic under high magnetic fields at 4K, was chosen for large (approx. 340 kg) forged turn buckles. This report describes the forging and heat-treatment optimization program that resulted in good sigma y and K/sub IC/ over the 4 to 300K range of service-temperatures and the verification tests run on a pre-production forging and actual production parts.

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

    NASA Astrophysics Data System (ADS)

    Shahriari, D.; Sadeghi, M. H.; Amiri, A.; Cheraghzadeh, M.

    2010-06-01

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

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

    SciTech Connect

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

    2010-06-15

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

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

    Microsoft Academic Search

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

    2007-01-01

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

  13. Application of bivariate parameter design to the optimization of the operating conditions of a turning process

    Microsoft Academic Search

    C.-Y. Chou; C.-H. Chen; C.-C. Yang; C.-C. Wu

    2005-01-01

    Parameter design, introduced by Taguchi, has been shown to be an effective approach for improving quality and productivity at low cost. The present article reports a case study of the application of parameter design to the determination of the optimal operating conditions of an integrated numerical control (NC) lathe such that the roundness and surface roughness of the cylindrical workpieces,

  14. Development of Processing Parameters for Organic Binders Using Selective Laser Sintering

    NASA Technical Reports Server (NTRS)

    Mobasher, Amir A.

    2003-01-01

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

  15. Open-Die Forging of Structurally Porous Sandwich Panels D.M. ELZEY and H.N.G. WADLEY

    E-print Network

    Wadley, Haydn

    Open-Die Forging of Structurally Porous Sandwich Panels D.M. ELZEY and H.N.G. WADLEY Structurally porous metal sandwich panels consisting of dense face sheets and porous cores of controlled relative-die forging of such a plastically compressible sandwich panel is developed. An effective yield potential

  16. An Algorithm of Tool-Path Optimization for High-Speed Machining Deep-Cavity Precision Forging Die

    Microsoft Academic Search

    Q. P. Sun; Q. L. Chen; Q. F. Wang; W. H. Liao

    2009-01-01

    Aiming at the difficulty of maintaining the contour precision of forging die with deep pocket, an optimization algorithm of tool-path generation for high speed machining (abbr. HSM) forging die with deep cavity is proposed in this paper. In terms of measuring errors of pocketing die, a mathematical model correlation to the length of a tool-path, the available length of a

  17. A friction model for cold forging of aluminum, steel and stainless steel provided with conversion coating and solid film lubricant

    Microsoft Academic Search

    N. Bay; M. Eriksen; X. Tan; O. Wibom

    2011-01-01

    Adopting a simulative tribology test system for cold forging the friction stress for aluminum, steel and stainless steel provided with typical lubricants for cold forging has been determined for varying normal pressure, surface expansion, sliding length and tool\\/work piece interface temperature. The results show, that friction is strongly influenced by normal pressure and tool\\/work piece interface temperature, whereas the other

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    NASA Technical Reports Server (NTRS)

    Khoshti, Ajay

    2014-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Koshti, Ajay M.

    2014-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Koshti, Ajay M.

    2014-03-01

    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.

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

    Microsoft Academic Search

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

    2008-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    Behrens, B.-A.; Hagen, T.; Röhr, S.; Sidhu, K. B.

    2007-05-01

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

  4. Ultrasound-aided leather dyeing: a preliminary investigation on process parameters influencing ultrasonic technology for large-scale production

    Microsoft Academic Search

    Venkatasubramanian Sivakumar; Gopalaraman Swaminathan; Paruchuri Gangadhar Rao; Thirumalachari Ramasami

    2009-01-01

    The application of ultrasound to leather processing has a significant role for more efficient and advanced manufacturing techniques\\u000a for leather production. The effect of important process parameters for scale-up such as mechanical agitation, float, and concentration\\u000a of dye bath has been experimentally examined. The results indicate that float level and dye bath concentration has significant\\u000a effect on exhaustion of dye.

  5. Arrhenius parameters for the rate process leading to catastrophic damage of AlGaAs-GaAs laser facets

    Microsoft Academic Search

    A. Moser; E. E. Latta

    1992-01-01

    The time dependence of catastrophic optical mirror damage (COMD) is investigated for cw operation of AlGaAs-GaAs quantum well lasers. The apparent Arrhenius parameters (i.e., the activation energy and pre-exponential factor) for the rate process leading to COMD are determined. In particular, we compare the rate process for various cleaved facets with and without a subsequent plasma oxidation step. Analysis of

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

    Microsoft Academic Search

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

    2006-01-01

    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

  7. Asymptotic analysis of the role of spatial sampling for covariance parameter estimation of Gaussian processes

    E-print Network

    Paris-Sud XI, Université de

    in details. Keywords: Uncertainty quantication, metamodel, Kriging, covariance parameter estimation, maximum for the analysis of complex computer models [27]. We will address the case of Kriging models, which consist

  8. Finite Element Modeling of Superplastic Sheet Forming Processes. Identification of Rheological and Tribological Parameters by Inverse Method

    Microsoft Academic Search

    Michel Bellet; Elisabeth Massoni; Serge Boude

    2004-01-01

    Superplastic forming is a thermoforming-like process commonly applied to titanium and aluminum alloys at high temperature and in specific conditions. This paper presents the application of an inverse analysis technique to the identification of rheological and tribological parameters. The method consists of two steps. First, two different kinds of forming tests have been carried out for rheological and tribological identification,

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    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.

  10. Optimization of process parameters for supercritical carbon dioxide extraction of Passiflora seed oil by response surface methodology

    Microsoft Academic Search

    Shucheng Liu; Feng Yang; Chaohua Zhang; Hongwu Ji; Pengzhi Hong; Chujin Deng

    2009-01-01

    Response surface methodology (RSM) was employed to optimize the process parameters of supercritical carbon dioxide extraction of the passion fruit seed oil. The effects of temperature, pressure and extraction time on the oil yield were investigated. Results showed that the data were adequately fitted into the second-order polynomial model. The linear and quadratic of independent variables, temperature, pressure and extraction

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

    Microsoft Academic Search

    S. C Juang; Y. S Tarng

    2002-01-01

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

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

    Microsoft Academic Search

    N. A. Noykova; M. Gyllenberg

    2000-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  14. Study of Meltblown Structures Formed By Robotic and Meltblowing Integrated System: Impact of Process Parameters On Fiber Diameter Distributions

    Microsoft Academic Search

    Raoul Farer; Subhash K. Batra; Tushar K. Ghosh; Eddie Grant; Abdelfattah M. Seyam

    In previous publication, the influence of process parameters on the fiber orientation of the meltblown web was evaluated (4). The meltblown webs were formed using Robotic Fiber Assembly and Control System (RFACS), which is described in previous publications (3, 4). In this paper, parametric stud- ies evaluating the effect of polymer throughput rate, attenuat- ing air pressure and temperature, and

  15. 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

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

    2009-01-01

    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

  16. The Use of Routine Process Capability for the Determination of Process Parameter Criticality in Small-molecule API Synthesis

    Microsoft Academic Search

    Kevin D. Seibert; Shanthi Sethuraman; Jerry D. Mitchell; Kristi L. Griffiths; Bernard McGarvey

    2008-01-01

    During the development of a pharmaceutical chemical process, it is vital to establish a control strategy that will ensure\\u000a the process performance and fitness for use of the active pharmaceutical ingredient (API), which in turn is essential to the\\u000a drug product performance and its fitness for use. As part of the control strategy, it is very important to understand and

  17. Characterization of Cracking and Crack Growth Properties of the C5A Aircraft Tie-Box Forging

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Smith, Stephen W.; Newman, John A.; Willard, Scott A.

    2003-01-01

    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.

  18. iPads as Placed Resources: Forging Community in Online and Off line Spaces

    ERIC Educational Resources Information Center

    Rowsell, Jennifer; Saudelli, Mary Gene; Scott, Ruth Mcquirter; Bishop, Andrea

    2013-01-01

    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…

  19. HotEye (tm) Based Coordinate Measuring Machine for Forging Industry

    SciTech Connect

    OG Technologies

    2003-06-09

    The objective of this project is to develop a 3 dimensional measurement system for the domestic forging industry based on HotEye{trademark}. This technology will allow high definition camera to accurately image a red hot object. The project marries conventional Coordinate Measurement Machine ''CMM'' technology to HotEye{trademark} technology to permit the accurate measurement of forged parts while they are at high temperature. Being able to take such measurements will dramatically reduce the amount of scrap produced by the domestic forging industry. This industry wastes a significant amount of energy because of the high rate of scrap it produces. OGT will: (1) Develop a 3D measurement sensor head that will work on a part at a temperature up to 1,450 C with an accuracy of 0.1mm or better and with a scanning speed of less than 10 seconds for an area of 100mm x 100mm. (2) Develop a Virtual-Fixturing software package to alleviate the need of precise hard fixturing. (3) Integrate the 3D measurement sensor head and the Virtual-Fixturing software into a standard CMM, both hardware (replacing the probes) and software (data format and user interface match) so that the system can automatically perform a complete preprogrammed measurement of a hot product. (4) Test and evaluate the system in a forging facility.

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    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.

  1. Position forging attacks in Vehicular Ad Hoc Networks: Implementation, impact and detection

    Microsoft Academic Search

    Jyoti Grover; Manoj Singh Gaur; Vijay Laxmi

    2011-01-01

    Vehicular Ad Hoc Network (VANET) applications operate on the principle of periodic exchange of messages between nodes. However, a malicious node can create multiple virtual identities for transmitting fake messages using different forged positions. This creates an illusion of a non-existent event. In VANET, each vehicle periodically broadcasts its identity (ID), time and current geographic position in beacon packets. Node

  2. Social Work and Engineering Collaboration: Forging Innovative Global Community Development Education

    ERIC Educational Resources Information Center

    Gilbert, Dorie J.

    2014-01-01

    Interdisciplinary programs in schools of social work are growing in scope and number. This article reports on collaboration between a school of social work and a school of engineering, which is forging a new area of interdisciplinary education. The program engages social work students working alongside engineering students in a team approach to…

  3. Benefits of High Performance Computing applied to the numerical simulation of forged parts

    E-print Network

    Paris-Sud XI, Université de

    Benefits of High Performance Computing applied to the numerical simulation of forged parts M at the designer's level on a daily basis in an industrial and highly competitive environment. This has been achieved through ongoing software development in order to fully benefit from continuously faster computer

  4. Micromechanisms of fatigue crack growth in a forged Inconel 718 nickel-based superalloy

    Microsoft Academic Search

    C. Mercer; A. B. O. Soboyejo; W. O. Soboyejo

    1999-01-01

    The micromechanisms of fatigue crack propagation in a forged, polycrystalline IN 718 nickel-based superalloy are evaluated. Fracture modes under cyclic loading were established by scanning electron microscopy analysis. The results of the fractographic analysis are presented on a fracture mechanism map that shows the dependence of fracture modes on the maximum stress intensity factor, Kmax, and the stress intensity factor

  5. T & I--Metalworking, Forging. Kit No. 55. Instructor's Manual [and] Student Learning Activity Guide.

    ERIC Educational Resources Information Center

    Lake, Robert J.

    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…

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

    NASA Astrophysics Data System (ADS)

    Ali, Adilah Mat; Ahmad, Sahrim Hj.

    2013-05-01

    Polymer nanocomposite of multi-walled carbon nanotubes (MWCNT) nanoparticles incorporated with polylactic acid (PLA) and liquid natural rubber (LNR) as compatibilizer were prepared via melt blending method using the Haake Rheomix internal mixer. In order to obtain the optimal processing parameter, the nanocomposite with 89 wt % of PLA was blended with 10 wt % of LNR and 1 wt % of MWCNTs were mixed with various mixing parameter condition; mixing temperature, mixing speed and mixing time. The optimum processing parameter of the composites was obtained at temperature of 190°C, rotation speed of 90 rpm and mixing time of 14 min. Next, the effect of MWCNTs loading on the tensile properties of nanocomposites was investigated. The nanocomposites were melt blended using the optimal processing parameter with MWCNTs loading of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4 wt %. The result showed that the sample with 3.5 wt % of MWCNTs gave higher tensile strength and Young's modulus. The SEM micrographs confirmed the effect of good dispersion of MWCNTs and their interfacial bonding in PLA nanocomposites. However, the elongation at break decreased with increasing the percentage of MWCNTs.

  7. Study and optimization of the parameters governing the block copolymer self-assembly: toward a future integration in lithographic process

    NASA Astrophysics Data System (ADS)

    Chevalier, X.; Tiron, R.; Upreti, T.; Gaugiran, S.; Navarro, C.; Magnet, S.; Chevolleau, T.; Cunges, G.; Fleury, G.; Hadziioannou, G.

    2011-04-01

    In this paper, we present our studies on polystyrene-b-polymethylmethacrylate (PS-b-PMMA) block copolymer systems to produce cylindrical morphology in the thin film configuration. More specifically, we focus on the different accessible parameters to optimize the processing conditions for the self-assembly of this block copolymer. We studied the self-assembly process of the block copolymer film spin-coated on different random brushes obtained by varying several parameters such as the film thickness, and the annealing time and temperature. We have shown that the thin-film morphology (in-plane, out-of-plane or mixed ones) critically depends on those different parameters and that a subtle optimization of them will provide almost defect-free nanostructures. We also examined the morphology of the self assembled features in the interior of the block copolymer thin film after the subsequent removal of the PMMA block structured domain. This process leads to the film top-nanostructures spanning across the whole film thickness. We evidenced also that high aspect-ratio nanostructures in bulk silicon can be obtained with such optimized films through CMOS-compatible dry-etching approach. To conclude, we show that the above-optimized self assembly parameters can be directly combined with 193nm-resist based patterns through the graphoepitaxy approach to achieve useful features for advanced lithography.

  8. Evaluation of the Deformation Behavior of a Semi-solid Hypereutectic Al-Si Alloy Compressed in a Drop-Forge Viscometer

    NASA Astrophysics Data System (ADS)

    Fukui, Yasuyoshi; Nara, Daisaku; Kumazawa, Noriyoshi

    2015-05-01

    The rheological behavior of an Al-25 mass pct Si alloy, i.e., a hypereutectic Al-Si alloy, was investigated to determine its processability under semi-solid forming conditions. To measure the viscosity of the semi-solid alloy, a parallel-plate drop-forge viscometer similar to that devised by Yurko and Flemings was developed. Drop-forge experiments revealed that the viscosity initially decreased as the shear rate increased and subsequently increased as the shear rate decreased. Thus, the viscosity reached a minimum at approximately the maximum shear rate. The summarized relationship between the viscosity, ? [Pa s], and the shear rate, [s-1], can be described by the power-law model ? = 1.78 × 107 -1.5. The decrease in viscosity as a function of the shear rate derived from this equation depends on both the temperature and the applied force but not the duration of deformation. A convex curve was obtained when the effective duration of deformation, i.e., the actual compression time, was plotted as a function of the viscosity and the effective duration of deformation reached a maximum at approximately ? = 30 kPa s ( = 70 s-1). The origin of this profile can be attributed to a combination of both a moderate working time and an adequate deformation, which resulted from a decrease in the deformation resistance accompanied by a lowering of the viscosity. The viscosity at the maximum effective duration of deformation thus corresponds to the transition point for the change in the flow process dominant factor from plastic forming (forging) to casting. Therefore, the viscosity ? = 30 kPa s is believed to be the optimum viscosity for the semi-solid forming of the Al-25 mass pct Si alloy. The approximate temperature condition can be ranged from 855 K to 859 K (582 °C to 586 °C).

  9. On-line process optimization: parameter tuning for the real time evolution (RTE) approach

    Microsoft Academic Search

    Sebastián Eloy Sequeira; Miguel Herrera; Moisès Graells; Luis Puigjaner

    2004-01-01

    This paper describes a methodology proposed for tuning real time evolution (RTE) parameters RTE has been introduced in a previous work [Industrial Engineering and Chemical Research 41 (7) (2002) 1815] as a new approach to on-line model-based optimization. Such strategy differs from classical real time optimization (RTO) in that waiting for steady state is not necessary and also in the

  10. Brief Report: Coherent Motion Processing in Autism: Is Dot Lifetime an Important Parameter?

    ERIC Educational Resources Information Center

    Manning, Catherine; Charman, Tony; Pellicano, Elizabeth

    2015-01-01

    Contrasting reports of "reduced" and "intact" sensitivity to coherent motion in autistic individuals may be attributable to stimulus parameters. Here, we investigated whether dot lifetime contributes to elevated thresholds in children with autism. We presented a standard motion coherence task to 31 children with autism and 31…

  11. Maize-Based Gluten-Free Bread: Influence of Processing Parameters on Sensory and Instrumental Quality

    Microsoft Academic Search

    Carla Brites; Maria João Trigo; Carla Santos; Concha Collar; Cristina M. Rosell

    2010-01-01

    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

  12. Optimising lead-free screen-printing and reflow process parameters

    Microsoft Academic Search

    Claire Ryan; S. O'Neill; J. Donovan; J. Punch; B. Rodgers; E. Murphy

    2004-01-01

    Introducing a lead-free solder replacement requires studies to be conducted by electronic assembly manufacturers in order to determine process alteration requirements and suitability of current equipment. This paper presents the results of an investigation of the screen-printing and reflow steps of the surface mount technology (SMT) manufacturing process. Experiments were conducted to investigate these two processes using a tin-silver-copper (95.5Sn3.8Ag0.7Cu)

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

    PubMed

    Addison, Paul S

    2014-12-01

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

  14. PROPERTIES AND PARAMETER SELECTION FOR PHASE SYNCHRONY PROCESSING OF EEG SIGNALS

    E-print Network

    Beex, A. A. "Louis"

    application in EEG (electroencephalogram) processing. A Phase Synchrony Processor is proposed and its. Introduction The electroencephalogram (EEG) is a weak (generally, less than 300 V) electrical signal obtained

  15. The effect of film properties and laser processing parameters on the laser ablation of molybdenum thin films

    NASA Astrophysics Data System (ADS)

    Schneller, Eric; Rodrigues, Rafael; Dhere, Neelkanth G.; Kar, Aravinda

    2014-10-01

    Molybdenum is commonly used as the electrical back contact for Cu(In,Ga)(Se,S)2 thin-film solar cells. In order to create a monolithically interconnected device, scribing of the molybdenum layer is required. This scribe, known as the P1 scribe, is commonly carried out through laser processing. Optimization of this laser scribing has been carried out using a 532nm pulsed Nd:YAG laser. It was found that two specific regimes of processing resulted in defect free scribes. These regimes are low fluency and high pulse overlap, and high fluency and low pulse overlap. Film properties, including the microstructure, surface oxidation, and internal stress, were studied to understand their effect on the laser ablation process. It was observed that a thin layer of oxidation resulted in significant heat affected zone during the laser ablation process. A discussion of the optimal film properties and laser processing parameters is presented.

  16. Processing/formulation parameters determining dispersity of chitosan particles: an ANNs study.

    PubMed

    Esmaeilzadeh-Gharehdaghi, Elina; Faramarzi, Mohammad Ali; Amini, Mohammad Ali; Moazeni, Esmaeil; Amani, Amir

    2014-01-01

    Although a great number of studies may be found in literature about the parameters affecting the size of chitosan nanoparticles, no systematic work so far has detailed the factors affecting the polydispersity of chitosan as an important factor determining the quality of many preparations. Herein, using artificial neural networks (ANNs), four independent variables, namely, pH and concentration of chitosan solution as well as time and amplitude of sonication of the solution were studied to determine their influence on the polydispersity of solution. We found that in an ultrasound prepared nanodispersion of chitosan, all the four input parameters have reverse but non-linear relation with the polydispersity of the nanoparticles. PMID:23795904

  17. Brief Report: Coherent Motion Processing in Autism: Is Dot Lifetime an Important Parameter?

    PubMed

    Manning, Catherine; Charman, Tony; Pellicano, Elizabeth

    2015-07-01

    Contrasting reports of reduced and intact sensitivity to coherent motion in autistic individuals may be attributable to stimulus parameters. Here, we investigated whether dot lifetime contributes to elevated thresholds in children with autism. We presented a standard motion coherence task to 31 children with autism and 31 typical children, with both limited and unlimited lifetime conditions. Overall, children had higher thresholds in the limited lifetime condition than in the unlimited lifetime condition. However, children with autism were affected by this manipulation to the same extent as typical children and were equally sensitive to coherent motion. Our results suggest that dot lifetime is not a critical stimulus parameter and speak against pervasive difficulties in coherent motion perception in children with autism. PMID:25604585

  18. Effect of Process Parameters on Foam Bitumen-based Road Material Production at Ambient Temperature

    Microsoft Academic Search

    Bogdan Cazacliu; Marian Peticila; Bernard Guieysse; Jacques Colange; Cédric Leroux; Jacques Bonvallet; Richard Blaszczyk

    2008-01-01

    The production by batch cold-mix technique of foam bitumen-based bound graded aggregates is studied at laboratory scale. The influence of some mixing parameters (mixing system, mixing time, shaft speed, aggregates temperature and foam characteristics) and bitumen content is analyzed. An original developed test permits a measure of the mixture microstructure. A twin-shaft mixer gives better results than a planetary mixer.

  19. EFFECT OF PROCESSING PARAMETERS ON ZERO-GAP LASER WELDS MADE ON MULTI-COATED STEEL

    Microsoft Academic Search

    Ashish Dasgupta; Jyoti Mazumder

    We are presenting a study on zero-gap CO2 laser lap welding of multi-coated steel using alloying additives. Steel coated with multiple elements like zinc, nickel, aluminum, epoxy resin etc., being considered for use in fuel tanks for newer alternative fuels, was experimented and the effects of welding parameters on properties like porosity, hardness, bead quality etc. was investigated. An L-9

  20. Real-Time Parameter Estimation Method Applied to a MIMO Process and its Comparison with an Offline Identification Method

    SciTech Connect

    Kaplanoglu, Erkan [Marmara University, Technical Education Faculty, Dept. of Mechatronics Kadikoy, 34722 Istanbul (Turkey); Safak, Koray K. [Yeditepe University, Dept. of Mechanical Engineering Kayisdagi, 34755 Istanbul (Turkey); Varol, H. Selcuk [Marmara University, Technical Education Faculty, Dept. of Electronics and Computer Kadikoy, 34722 Istanbul (Turkey)

    2009-01-12

    An experiment based method is proposed for parameter estimation of a class of linear multivariable systems. The method was applied to a pressure-level control process. Experimental time domain input/output data was utilized in a gray-box modeling approach. Prior knowledge of the form of the system transfer function matrix elements is assumed to be known. Continuous-time system transfer function matrix parameters were estimated in real-time by the least-squares method. Simulation results of experimentally determined system transfer function matrix compare very well with the experimental results. For comparison and as an alternative to the proposed real-time estimation method, we also implemented an offline identification method using artificial neural networks and obtained fairly good results. The proposed methods can be implemented conveniently on a desktop PC equipped with a data acquisition board for parameter estimation of moderately complex linear multivariable systems.

  1. Effect of process parameters on properties of argon–nitrogen plasma for titanium nitride film deposition

    SciTech Connect

    Saikia, Partha; Kakati, Bharat [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782 402, Kamrup, Assam (India)] [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782 402, Kamrup, Assam (India)

    2013-11-15

    In this study, the effect of working pressure and input power on the physical properties and sputtering efficiencies of argon–nitrogen (Ar/N{sub 2}) plasma in direct current magnetron discharge is investigated. The discharge in Ar/N{sub 2} is used to deposit TiN films on high speed steel substrate. The physical plasma parameters are determined by using Langmuir probe and optical emission spectroscopy. On the basis of the different reactions in the gas phase, the variation of plasma parameters and sputtering rate are explained. A prominent change of electron temperature, electron density, ion density, and degree of ionization of Ar is found as a function of working pressure and input power. The results also show that increasing working pressure exerts a negative effect on film deposition rate while increasing input power has a positive impact on the same. To confirm the observed physical properties and evaluate the texture growth as a function of deposition parameters, x-ray diffraction study of deposited TiN films is also done.

  2. Influence of laser parameters on quality of microholes and process efficiency

    NASA Astrophysics Data System (ADS)

    Feuer, A.; Kunz, C.; Kraus, M.; Onuseit, V.; Weber, R.; Graf, T.; Ingildeev, D.; Hermanutz, F.

    2014-03-01

    To enable the direct-spinning process of super-micro fibres (< 0.5 dtex) suitable for novel medical, hygienical and technical products microhole arrays with diameters down to 25 ?m in very high quality are required. Using ultrashort pulses together with a helical drilling optics microholes with high accuracy were manufactured in metals of a thickness in the range of 0.3 mm. However, the required process time for a single microhole ranges up to several ten seconds. Simple energy balance considerations show that higher averaged powers - either achieved with larger pulse energies or an increased repetition rate - considerable reduce the process time. In this case plasma formation and heat accumulation show an increased formation of melt and recast. Thus, the objective is to increase the productivity while maintaining consistent quality of the microholes. With this aim, the influence of pulse energy and repetition rate on the borehole geometry, processing quality and process efficiency was investigated for helical drilling. In the present research work a TruMicro 5250 laser source (tp = 8 ps, ?=515 nm, fR=800 kHz) was used. To determine the process time of the microhole the transmitted laser radiation was recorded. A systematic evaluation of the process quality and process time dependent on pulse energy and repetition rate will be presented in this contribution. First laser manufactured spinning nozzles with microhole diameters down to 25 ?m processed in 0.24 mm thick AuPt alloy were used to fabricate unique super-micro fibres with yarn counts down to 0.2 dtex.

  3. Effect of electroless process parameters for nickel-phosphorous coatings on carbon fibres

    Microsoft Academic Search

    Z. Abdel Hamid; A. Abdel Aal

    2010-01-01

    Purpose – The purpose of this paper is to investigate the deposition of uniform, adherent and crack-free Ni-P thin films on carbon fibres using the electroless deposition technique. Design\\/methodology\\/approach – Before applying the electroless process, the carbon fibre surfaces must be subjected to several treatment processes to remove the organic binder, etching and surface metallization. The surface morphology of the

  4. Effect of process parameters on bond formation during ultrasonic consolidation of aluminum alloy 3003

    Microsoft Academic Search

    G. D. Janaki Ram; Y. Yang; B. E. Stucker

    2006-01-01

    Ultrasonic consolidation (UC) is a novel additive manufacturing process wherein three-dimensional metallic objects are fabricated layer by layer in an automated fashion from thin metal foils. The process has immense potential for fabrication of injection molding tooling with conformai cooling channels, fiber-reinforced composites, multi-material structures, smart structures, and others. The proportion of bonded area in relation to the total interface

  5. Characterization of residual stresses in heat treated Ti-6Al-4V forgings by machining induced distortion

    NASA Astrophysics Data System (ADS)

    Regener, B.; Krempaszky, C.; Werner, E.

    2010-06-01

    To provide a solid base for improved material exploitation in dimensioning calculations it is necessary to determine the stress state in the part prior to service loading. In order to achieve higher material strength at elevated temperatures, the surface temperature gradient with respect to time has to be sufficiently high during heat treatment. This results in non-negligable residual stresses that can reduce the allowable load level upon which yielding occurs. For titanium alloys there are two common heat treatments, namely solution treatment and mill annealing. The latter one is the method of choice within the presented project. Mill annealing is utilized in order to significantly reduce the residual stresses in the parts without loosing much of the improved strength at elevated temperatures. Quantification of residual stresses is done by solving an inverse problem. From the measurement of distortion, induced by dividing the investigated part, the residual stress state can be calculated via analytical modeling or correlation with finite element models. To assure a minimum perturbation of the residual stress state during specimen production, dividing of the part is accomplished by electric discharge machining. The parts of interest are v-shaped prisms with a length of approximatly 450 mm and a thickness in the cross sectional area from about 20 mm to 45 mm. Figure 1(a) shows the forged part and 1(b) the dimensions of the cross section in millimeters as well as the material properties considered in the finite element model. The heat exchange between the part and the environment is modelled as heat transfer by convection superimposed with heat radiation. Since the parts are exposed to air during forging and heat treatment, the surface develops a strongly adhesive oxide layer, the so called alpha-case. After forging the parts are cooled in air and heat treated at a temperature of 720° C for a duration of 120 min. Subsequent air cooling and removing the alpha-case by shot peening and chemical treatment in a mixture of nitric and hydroflouric acid finishes the processing. The residual stress state in the parts is quantified through correlation of results obtained by finite element simulations and high precision deflection experiments. Experimental measuring errors are minimized by using the capability of the wire cutting machine to measure locations on the specimens with respect to the fixed machine coordinate system. A sophisticated design of cutting operations allows an analysis of the part without removing the fixture and hence makes it possible to achieve a very high accuracy of the displacement measurements of about 4 µm. The quality of the obtained results also depends on the finite element models describing the mechanics of the experimental investigations as precise as possible. Since numerical modeling of shot peening and chemical milling is rather complicated, the whole processing route of the shapes is simplified assuming that the individual contribution of all process steps to the residual stress state can be described by virtual heat transfer coefficients. The overall virtual heat transfer coefficient for the whole processing route is calculated from the linear superposition of the individual heat transfer coeffcients for each processing step. Detailed analysis of the obtained overall virtual heat transfer coefficients in comparison with experimentally obtained ones shows, that other processing steps besides the heat treatment considerably influence the residual stress state. In order to make the conducted simulation scheme applicable in practise, advanced finite element modeling techniques are developed. The experimentally derived deflection curves are correlated to the finite element results via a least square fit.

  6. The role of processing parameters on the magnetic properties of directionally solidified Bi\\/MnBi composites

    Microsoft Academic Search

    R. Pirich; D. Larson; G. Busch

    1979-01-01

    Eutectic and off-eutectic Bi\\/MnBi composites have been plane-front directionally solidified at various growth velocities and cooling rates. This results in elongated, aligned MnBi rods dispersed in a Bi terminal solid solution. Magnetization as a function of temperature (4.2, 77 and 295K) and applied field (up to 230 kOe) has been used to evaluate the influence of processing parameters on the

  7. Statistical analysis and validation of process parameters influencing lovastatin production by Monascus purpureus MTCC 369 under solid-state fermentation

    Microsoft Academic Search

    Bibhu Prasad Panda; Saleem Javed; Mohd. Ali

    2009-01-01

    Monascus, a fermented rice (red mold rice), was found to reduce total cholesterol and triglyceride in serum due to the presence of\\u000a lovastatin, a 3-hydroxy-3-methyl glutaryl coenzyme A (HMG-CoA) reductase inhibitor. Optimization and validation of different\\u000a process parameters such as temperature, fermentation time, inoculum volume, and pH of the solid medium was done using Box-Behnken’s\\u000a factorial design of response surface

  8. Characterization of the effects of process parameters on macrosegregation in a high-pressure die-cast Magnesium alloy

    Microsoft Academic Search

    Soon Gi Lee; G. R. Patel; A. M. Gokhale

    2005-01-01

    Normal and inverse solute segregations have been reported to occur in several Al-alloys as well as in some other nonferrous alloys. Nonetheless, these phenomena have not been studied in high-pressure die-cast (HPDC) Mg-alloys. This contribution reports an experimental metallographic evidence of inverse surface macrosegregation in a HPDC AM60 Mg-alloy and the effects of process parameters on the extent of inverse

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

    Microsoft Academic Search

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

    2005-01-01

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

  10. Defining blood processing parameters for optimal detection of cryopreserved antigen-specific responses for HIV vaccine trials

    Microsoft Academic Search

    Marta Bull; Deborah Lee; Jason Stucky; Ya-Lin Chiu; Abbe Rubin; Helen Horton; M. Juliana McElrath

    2007-01-01

    Interferon-gamma (IFN-?) ELISpot and intracellular cytokine staining (ICS) assays are routinely employed in clinical HIV vaccine trials to identify antigen-specific T cells in cryopreserved peripheral blood mononuclear cells (PBMC). Several parameters involved in blood collection, processing and shipping may influence immunological function of the resulting cells, including anticoagulant type, time from venipuncture to PBMC isolation\\/cryopreservation, method of PBMC isolation and

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

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

    SciTech Connect

    Not Available

    1994-01-01

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

  13. Determination of thermodynamic and transport parameters of naphthenic acids and organic process chemicals in oil sand tailings pond water.

    PubMed

    Wang, Xiaomeng; Robinson, Lisa; Wen, Qing; Kasperski, Kim L

    2013-07-01

    Oil sand tailings pond water contains naphthenic acids and process chemicals (e.g., alkyl sulphates, quaternary ammonium compounds, and alkylphenol ethoxylates). These chemicals are toxic and can seep through the foundation of the tailings pond to the subsurface, potentially affecting the quality of groundwater. As a result, it is important to measure the thermodynamic and transport parameters of these chemicals in order to study the transport behavior of contaminants through the foundation as well as underground. In this study, batch adsorption studies and column experiments were performed. It was found that the transport parameters of these chemicals are related to their molecular structures and other properties. The computer program (CXTFIT) was used to further evaluate the transport process in the column experiments. The results from this study show that the transport of naphthenic acids in a glass column is an equilibrium process while the transport of process chemicals seems to be a non-equilibrium process. At the end of this paper we present a real-world case study in which the transport of the contaminants through the foundation of an external tailings pond is calculated using the lab-measured data. The results show that long-term groundwater monitoring of contaminant transport at the oil sand mining site may be necessary to avoid chemicals from reaching any nearby receptors. PMID:23736740

  14. Developing LBM Process Parameters for Ti-6Al-4V Thin Wall Structures and Determining the Corresponding Mechanical Characteristics

    NASA Astrophysics Data System (ADS)

    Ahuja, Bhrigu; Schaub, Adam; Karg, Michael; Lechner, Michael; Merklein, Marion; Schmidt, Michael

    The Laser Beam Melting (LBM) process technology within the family of Additive Manufacturing technology is characterized by its ability to fabricate fully dense 3D structures directly from micro-sized metal powder. With the current state of the art, Ti-6Al-4V has been processed using LBM machine systems constituting a laser with a beam diameter of about 100 ?m. In order to fabricate structures with smaller wall thicknesses, processing of Ti-6Al-4V is attempted on the LBM machine system, Realizer SLM 50 consisting of a laser with a beam diameter 10 ?m. The proposed paper presents the development of process parameters for fabricating fully dense Ti-6Al-4V 3D structures using the LBM machine system, Realizer SLM 50. Further experiments are carried out to determine the wall thickness and mechanical properties achievable using the selected process parameters. Analysis and scientific arguments are presented to explain the influence of building direction and heat treatment on mechanical properties.

  15. Characterization of structural and hydrodynamic parameters changes due to dissolution and precipitation processes in limestone samples

    NASA Astrophysics Data System (ADS)

    Luquot, Linda; Roetting, Tobias; Carrera Ramirez, Jesus

    2015-04-01

    CO2 sequestration in deep geological formation is considered an option to reduce CO2 emissions in the atmosphere. After injection, the CO2 will slowly dissolve into the pore water producing low pH fluids with a high capacity for dissolving carbonates. Limestone rock dissolution induces geometrical parameters changes such as porosity, pore size distribution, or tortuosity which may consequently modify transport properties (permeability, diffusion coefficient). Characterizing these changes is essential for modelling flow and CO2 transport during and after the CO2 injection. Indeed, these changes can affect the storage capacity and injectivity of the formation. Very few published studies evaluate the transport properties changes (porosity, permeability, pore size distribution, diffusion coefficient) due to fluid-rock interactions (dissolution and/or precipitation). Here we report experimental results from the injection of acidic fluids (some of them equilibrated with gypsum) into limestone core samples of 25.4 mm diameter and around 25 mm length. We studied two different limestone samples: one composed of 73% of calcite and 27% of quartz, and the second one of 100% of dolomite. Experiments were realized at room temperature. Before and after each acidic rock attack, we measure the sample porosity, the diffusion coefficient and the pore size distribution. We also image the 3D pore network by X-ray microtomography to evaluate the same parameters. During percolation experiments, the permeability changes are recorded and chemical samples taken to evaluate calcite dissolution and gypsum precipitation. Several dissolution/precipitation-characterization cycles are performed on each sample in order to study the evolution and relation of the different parameters. These experiments show different dissolution regimes depending of the fluid acidity and of the limestone sample.

  16. Modeling and Analysis of Process Parameters for Evaluating Shrinkage Problems During Plastic Injection Molding of a DVD-ROM Cover

    NASA Astrophysics Data System (ADS)

    Öktem, H.

    2012-01-01

    Plastic injection molding plays a key role in the production of high-quality plastic parts. Shrinkage is one of the most significant problems of a plastic part in terms of quality in the plastic injection molding. This article focuses on the study of the modeling and analysis of the effects of process parameters on the shrinkage by evaluating the quality of the plastic part of a DVD-ROM cover made with Acrylonitrile Butadiene Styrene (ABS) polymer material. An effective regression model was developed to determine the mathematical relationship between the process parameters (mold temperature, melt temperature, injection pressure, injection time, and cooling time) and the volumetric shrinkage by utilizing the analysis data. Finite element (FE) analyses designed by Taguchi (L27) orthogonal arrays were run in the Moldflow simulation program. Analysis of variance (ANOVA) was then performed to check the adequacy of the regression model and to determine the effect of the process parameters on the shrinkage. Experiments were conducted to control the accuracy of the regression model with the FE analyses obtained from Moldflow. The results show that the regression model agrees very well with the FE analyses and the experiments. From this, it can be concluded that this study succeeded in modeling the shrinkage problem in our application.

  17. Temporal variations in parameters reflecting terminal-electron-accepting processes in an aquifer contaminated with waste fuel and chlorinated solvents

    USGS Publications Warehouse

    McGuire, Jennifer T.; Smith, Erik W.; Long, David T.; Hyndman, David W.; Haack, Sheridan K.; Klug, Michael J.; Velbel, Michael A.

    2000-01-01

    A fundamental issue in aquifer biogeochemistry is the means by which solute transport, geochemical processes, and microbiological activity combine to produce spatial and temporal variations in redox zonation. In this paper, we describe the temporal variability of TEAP conditions in shallow groundwater contaminated with both waste fuel and chlorinated solvents. TEAP parameters (including methane, dissolved iron, and dissolved hydrogen) were measured to characterize the contaminant plume over a 3-year period. We observed that concentrations of TEAP parameters changed on different time scales and appear to be related, in part, to recharge events. Changes in all TEAP parameters were observed on short time scales (months), and over a longer 3-year period. The results indicate that (1) interpretations of TEAP conditions in aquifers contaminated with a variety of organic chemicals, such as those with petroleum hydrocarbons and chlorinated solvents, must consider additional hydrogen-consuming reactions (e.g., dehalogenation); (2) interpretations must consider the roles of both in situ (at the sampling point) biogeochemical and solute transport processes; and (3) determinations of microbial communities are often necessary to confirm the interpretations made from geochemical and hydrogeological measurements on these processes.

  18. Selection of Wire Electrical Discharge Machining Process Parameters on Stainless Steel AISI Grade-304 using Design of Experiments Approach

    NASA Astrophysics Data System (ADS)

    Lingadurai, K.; Nagasivamuni, B.; Muthu Kamatchi, M.; Palavesam, J.

    2012-06-01

    Wire electrical discharge machining (WEDM) is a specialized thermal machining process capable of accurately machining parts of hard materials with complex shapes. Parts having sharp edges that pose difficulties to be machined by the main stream machining processes can be easily machined by WEDM process. Design of Experiments approach (DOE) has been reported in this work for stainless steel AISI grade-304 which is used in cryogenic vessels, evaporators, hospital surgical equipment, marine equipment, fasteners, nuclear vessels, feed water tubing, valves, refrigeration equipment, etc., is machined by WEDM with brass wire electrode. The DOE method is used to formulate the experimental layout, to analyze the effect of each parameter on the machining characteristics, and to predict the optimal choice for each WEDM parameter such as voltage, pulse ON, pulse OFF and wire feed. It is found that these parameters have a significant influence on machining characteristic such as metal removal rate (MRR), kerf width and surface roughness (SR). The analysis of the DOE reveals that, in general the pulse ON time significantly affects the kerf width and the wire feed rate affects SR, while, the input voltage mainly affects the MRR.

  19. Process parameters for high-yield Y:Ba:Cu:O superconductors

    NASA Astrophysics Data System (ADS)

    Ye, James; Hsieh, Peter Y.; Wang, Liu-Quan; Shaw, David; Mattocks, Peter; Wang, X. W.

    1988-02-01

    High Tc superconducting devices can be made from the bulk materials in a Y-Ba-Cu-O system. We report here the stability of bulk materials in order to understand methods to produce higher Tc and hopefully shorten the period of processing. Systematic measurements of resistivity, magnetization and X-ray diffraction have been made on samples that have the same chemical composition but different processing. The processing was varied to find the optimum combination of the calcining time, sintering time and annealing time at 650°C. We have found that the Tc is stable if the dominant phase remains. A ratio of Meissner: shielding magnetizations of 61:100 was found under optimum conditions. The intensity and position of the X-ray diffraction peak for (103) was independent of time but strongly dependent on processing. The magnetizations due to shielding and Meissner effects definitely change with time but their ratio remains the same. Anomalous behavior was observed in both resistance and magnetization at a processing-dependent temperature of about 160°K. The behavior was similar to that claimed on a superconductivity phase transition by other authors. Based on this study, the stability and degradation of superconducting devices associated with bulk material will be further investigated.

  20. Rate description of Fokker-Planck processes with time-periodic parameters

    NASA Astrophysics Data System (ADS)

    Kim, Changho; Talkner, Peter; Lee, Eok Kyun; Hänggi, Peter

    2010-05-01

    The large time dynamics of a periodically driven Fokker-Planck process possessing several metastable states is investigated. At weak noise transitions between the metastable states are rare. Their dynamics then represent a discrete Markovian process characterized by time dependent rates. Apart from the occupation probabilities, so-called specific probability densities and localizing functions can be associated to each metastable state. Together, these three sets of functions uniquely characterize the large time dynamics of the conditional probability density of the original process. Exact equations of motion are formulated for these three sets of functions and strategies are discussed how to solve them. These methods are illustrated and their usefulness is demonstrated by means of the example of a bistable Brownian oscillator within a large range of driving frequencies from the slow semiadiabatic to the fast driving regime.

  1. Optimization of processing parameters and ingredients for development of low-fat fibre-supplemented paneer.

    PubMed

    Singh, G; Kumar, A; Kumbhar, B K; Dar, B N

    2015-02-01

    Increasing demand of low calorie and high fibre containing products give impetus to dairy industry for development of a well palatable low calorie dairy products like paneer. The objective of the present study was to develop low-fat fibre-supplemented paneer. The ingredients were chosen for low-fat fibre- supplemented paneer to reduce the cost and calorie content besides providing the functional benefits. Optimization of ingredients was carried out in terms of independent variables viz wheat bran (0.4-0.8 %), maltodextrin (1-5 %), coagulation temperature (60-80 °C) and amount of citric acid solution (150-210 ml). Response Surface Methodology (RSM) was used to design the experiments and to select the optimum levels of ingredients. Paneer was made by using different levels of ingredients by coagulating hot milk using citric acid solution followed by pressing and dipping in chilled water for texturization. These parameters were evaluated in terms of physico-chemical parameters viz water activity, pH and acidity. Instrumental texture profile analysis (TPA) of paneer during optimization trials was done using TAXT 2i Texture Analyzer. The textural responses namely hardness, adhesiveness, springiness, cohesiveness, gumminess and chewiness were measured via Texture Analyzer. The sensory properties namely flavor, appearance, body and texture, mouth feel and overall acceptability of paneer samples were evaluated by a semi-trained panel of judges using 9-point hedonic scale. Full second order polynomial was developed to predict each response. All the textural and sensory responses were statistically analysed. PMID:25694679

  2. Effect of Process Parameters on Die Wear Behavior of Aluminum Alloy Rod Extrusion

    Microsoft Academic Search

    Tingting Li; Guoqun Zhao; Cunsheng Zhang; Yanjin Guan; Xuemei Sun; Hengkui Li

    2012-01-01

    In this paper, a subroutine that calculates die wear depth based on modified Archard's wear model was developed and then embedded into DEFORM-3D, with which the extrusion process of an aluminum alloy 7075 rod was simulated. Useful information was obtained from the numerical simulation, including interface pressure, the distribution of instantaneous temperature, the required extrusion force and the die wear

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

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  4. Influence of processing parameters on aluminium foam produced by space holder technique

    Microsoft Academic Search

    R. Surace; L. A. C. De Filippis; A. D. Ludovico; G. Boghetich

    2009-01-01

    The interesting properties of metal foams as light weight, good energy absorption, low thermal conductivity, recyclability have spurred new process developments with the goal to obtain materials with a good relation between properties and costs.The different manufacturing methods are classified according to the starting metal state: liquid, powdered or ionized. The aim of this study is to evaluate the morphological

  5. Validation and Estimation of Parameters for a General Probabilistic Model of the PCR Process

    E-print Network

    Ramakrishnan, Naren

    reaction (PCR), probabilistic model, yield. 1 #12;1 INTRODUCTION The polymerase chain reaction (PCR where all nucleotide reaction rates are the same. In this model the probability of binding of deoxy features of the PCR amplification process quantitatively. With a set of favorable reaction conditions

  6. Effect of silicon solar cell processing parameters and crystallinity on mechanical strength

    Microsoft Academic Search

    V. A. Popovich; A. Yunus; M. Janssen; I. M. Richardson; I. J. Bennett

    2011-01-01

    Silicon wafer thickness reduction without increasing the wafer strength leads to a high breakage rate during subsequent handling and processing steps. Cracking of solar cells has become one of the major sources of solar module failure and rejection. Hence, it is important to evaluate the mechanical strength of solar cells and influencing factors. The purpose of this work is to

  7. Effect of microstructure and processing parameters on mechanical strength of multicrystalline silicon solar cells

    Microsoft Academic Search

    V. A. Popovich; A. Yunus; M. Janssen; I. J. Bennett; I. M. Richardson

    2010-01-01

    Silicon wafer thickness reduction without increasing the wafer strength leads to a high breakage rate during subsequent handling and processing steps. Cracking of solar cells has become one of the major sources of solar module failure and rejection. Hence, it is important to evaluate the mechanical strength of solar cells and influencing factors. The purpose of this work is to

  8. Motion compensated image processing and optimal parameters for egg crack detection using modified pressure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shell eggs with microcracks are often undetected during egg grading processes. In the past, a modified pressure imaging system was developed to detect eggs with microcracks without adversely affecting the quality of normal intact eggs. The basic idea of the modified pressure imaging system was to ap...

  9. A finite-step global convergence algorithm for the parameter estimation of multichannel MA processes

    Microsoft Academic Search

    Lang Tong; Yujiro Inouye; Ruey-wen Liu

    1992-01-01

    An iterative algorithm for the identification of multichannel moving average (MA) processes using higher-order statistics is proposed. It is shown that the algorithm has a finite-step global convergence property. Three multichannel MA models, including one nonminimum-phase MA model, are estimated by this algorithm with satisfactory performances

  10. Association of coliform bacteria with wastewater particles: impact of operational parameters of the activated sludge process

    Microsoft Academic Search

    Frank J. Loge; Robert W. Emerick; Tim R. Ginn; Jeannie L. Darby

    2002-01-01

    The fraction of particles with associated coliform bacteria (PAC) in the activated sludge process was evaluated using a 16S rRNA oligonucleotide probe specific to the family Enterobacteriaceae. The PAC was found to decline exponentially with increasing mean cell residence times (MCRTs). The factors influencing the formation of PAC, identified with simplified mass balance relationships, are the concentration of particles, the

  11. Effects of process parameters on warm and electromagnetic hybrid forming of magnesium alloy sheets

    Microsoft Academic Search

    Zhenghua Meng; Shangyu Huang; Jianhua Hu; Wei Huang; Zhilin Xia

    2011-01-01

    As the lightest structural metal, magnesium (Mg) is attracting increasing interest from both the industrial and academic fields. Magnesium alloy parts are mainly processed by die casting due to their poor sheet formability at room temperature. Warm forming is a popular method of forming; Mg alloy sheets produced in this manner show excellent formability around 200–400°C. Electromagnetic forming (EMF) can

  12. Development of Alloy and Superalloy Large Shafts by Friction Welding Process

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  13. Influence of Processing Parameters on Induced Energy, Mechanical and Corrosion Properties of FSW Butt Joint of 7475 AA

    NASA Astrophysics Data System (ADS)

    Gupta, Rajesh Kumar; Das, Hrishikesh; Pal, Tapan Kumar

    2012-08-01

    Friction stir welding (FSW), a promising solid state joining process invented at TWI in 1991, was used to join 9 mm thick 7475 aluminum alloy which is considered essentially unweldable by fusion processes. In the present work, the process parameters such as tool rotational speed were varied from 300 to 1000 rpm for a travel speed of 50 mm/min and the influence of process parameters in terms of energy input on microstructure, hardness, tensile strength, and the corrosion property of 7475 aluminum joints was evaluated and analyzed. The maximum tensile strength of FSW joints was obtained at rotational speed of 400 rpm and traverse speed of 50 mm/min (59.2 kJ) which attributed maximum stirred zone area and maximum hardness. The maximum corrosion resistance properties of weld in 3.5% NaCl solution, however, were obtained at rotational speed of 1000 rpm and traverse speed of 50 mm/min. Furthermore, for a given weld, stirred zone showed improved corrosion properties than TMAZ.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  15. Influence of Punch Geometry on Process Parameters in Cold Backward Extrusion

    NASA Astrophysics Data System (ADS)

    Plan?ak, M.; Bariši?, B.; Car, Z.; Movrin, D.

    2011-01-01

    In cold extrusion of steel tools make direct contact with the metal to be extruded. Those tools are exposed to high contact stresses which, in certain cases, may be limiting factors in applying this technology. The present paper was bound to the influence of punch head design on radial stress at the container wall in the process of cold backward extrusion. Five different punch head geometries were investigated. Radial stress on the container wall was measured by pin load cell technique. Special tooling for the experimental investigation was designed and made. Process has been analyzed also by FE method. 2D models of tools were obtained by UGS NX and for FE analysis Simufact Forming GP software was used. Obtained results (experimental and obtained by FE) were compared and analyzed. Optimal punch head geometry has been suggested.

  16. Stabilization of IgG by supercritical fluid drying: Optimization of formulation and process parameters

    Microsoft Academic Search

    Nataša Jovanovi?; Andréanne Bouchard; Gerard W. Hofland; Geert-Jan Witkamp; Daan J. A. Crommelin; Wim Jiskoot

    2008-01-01

    The aim of this study was to stabilize human serum immunoglobulin G (IgG) by a supercritical fluid (SCF) drying process. Solutions containing IgG (20mg\\/ml) and trehalose or hydroxypropyl-?-cyclodextrin in a 1:4 (w\\/w) ratio were sprayed into a SCF phase consisting of CO2 and ethanol at 100bar and 37°C. Initially, a set of drying conditions previously developed to successfully stabilize lysozyme

  17. Thermal Decomposition of Some Chemical Compounds Used As Food Preservatives and Kinetic Parameters of This Process

    Microsoft Academic Search

    J. Mas?owska; M. Wi?d?ocha

    2000-01-01

    Thermal decomposition processes of selected chemicals used as food preservatives such as sodium formate, sodium propionate,\\u000a sodium nitrates(V and III) and sodium sulphate(IV) were examined by the derivatographic method. Based on the curves obtained,\\u000a the number of decomposition stages and characteristic temperatures of these compounds have been found. Mass decrements calculated\\u000a from TG curves ranged from 28.9% for sodium formate

  18. Dry Matter Loss During Nixtamalization of a White Corn Hybrid: Impact of Processing Parameters

    Microsoft Academic Search

    D. Sahai; I. Surjewan; J. P. Mua; M. O. Buendia; M. Rowe; D. S. Jackson

    2000-01-01

    Cereal Chem. 77(2):254-258 Nixtamalization is the primary step in the production of products such as corn chips, tortilla chips, tacos, and corn tortillas. The process involves cooking and steeping of corn in lime and excess water to produce nixta- mal. Commercial nixtamalization results in 5-14% corn solids loss in the liquid generated during cooking-steeping and washing. Loss of corn solids

  19. Global Sensitivity Analysis for the determination of parameter importance in bio-manufacturing processes.

    PubMed

    Chhatre, Sunil; Francis, Richard; Newcombe, Anthony R; Zhou, Yuhong; Titchener-Hooker, Nigel; King, Josh; Keshavarz-Moore, Eli

    2008-10-01

    The present paper describes the application of GSA (Global Sensitivity Analysis) techniques to mathematical models of bioprocesses in order to rank inputs such as feed titres, flow rates and matrix capacities for the relative influence that each exerts upon outputs such as yield or throughput. GSA enables quantification of both the impact of individual variables on process outputs, as well as their interactions. These data highlight those attributes of a bioprocess which offer the greatest potential for achieving manufacturing improvements. Whereas previous GSA studies have been limited to individual unit operations, this paper extends the treatment to an entire downstream process and illustrates its utility by application to the production of a Fab-based rattlesnake antivenom called CroFab [(Crotalidae Polyvalent Immune Fab (Ovine); Protherics U.K. Limited]. Initially, hyperimmunized ovine serum containing rattlesnake antivenom IgG (product), other antibodies and albumin is applied to a synthetic affinity ligand adsorbent column to separate the antibodies from the albumin. The antibodies are papain-digested into Fab and Fc fragments, before concentration by ultrafiltration. Fc, residual IgG and albumin are eliminated by an ion-exchanger and then CroFab-specific affinity chromatography is used to produce purified antivenom. Application of GSA to the model of this process showed that product yield was controlled by IgG feed concentration and the synthetic-material affinity column's capacity and flow rate, whereas product throughput was predominantly influenced by the synthetic material's capacity, the ultrafiltration concentration factor and the CroFab affinity flow rate. Such information provides a rational basis for identifying the most promising strategies for delivering improvements to commercial-scale biomanufacturing processes. PMID:18205624

  20. CO2 laser cutting: analytical dependence of the roughness of the cut edge on the experimental parameters and process monitoring

    NASA Astrophysics Data System (ADS)

    Sforza, Patrizia; Santacesaria, Vincenzo

    1994-09-01

    Over the last few years laser cutting has been widely introduced in industrial production lines, mainly due to the high processing speeds. In the present work a fundamental aspect of the cutting process of metals has been considered: the formation of periodic striations on the cut edge that greatly affects the quality of the treated samples. Therefore this paper is devoted to the study of the roughness of the cut surfaces with a particular attention to the dependence of this parameters on the working conditions. For a better understanding of the variables involved in the process, a comparison of the experimental data with the results of an analytical model has been performed. Furthermore a real time monitoring of the infrared emission coming from the interaction zone has been carried out by means of an electrooptic device properly developed for the measurements of the local temperature. A correlation between these data and the roughness measurements has been found.

  1. Effect of drying parameters on physiochemical and sensory properties of fruit powders processed by PGSS-, Vacuum- and Spray-drying.

    PubMed

    Feguš, Urban; Žigon, Uroš; Petermann, Marcus; Knez, Željko

    2015-01-01

    Aim of this experimental work was to investigate the possibility of producing fruit powders without employing drying aid and to investigate the effect of drying parameters (e.g., process temperature and pressure) on the final powder characteristics such as retention of colour, flavour and antioxidant activity. Raw fruit materials (banana puree, strawberry puree and blueberry concentrate) were processed using three different drying techniques operating under sub-atmospheric (freeze-drying), atmospheric (spray-drying) and high-pressure (PGSS-drying) conditions. The results obtained from the experimental work indicate that investigated fruit powders without or with minimal addition of maltodextrin can be produced. Additionally, it was observed that an increase in process temperature results in a higher loss of colour, antioxidant activity and intensity of the flavour profile. PMID:26085433

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

    PubMed

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

    2011-01-01

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

  3. Deformation modelling in layered manufacturing of metallic parts using gas metal arc welding: effect of process parameters

    NASA Astrophysics Data System (ADS)

    Mughal, M. P.; Fawad, H.; Mufti, R. A.; Siddique, M.

    2005-10-01

    Residual stress induced deformations are a major cause of loss in tolerances in solid freeform fabrication processes employing direct metal deposition. In this paper a 2D finite element thermo-mechanical model is being presented to predict the residual stress induced deformations with application to processes where material is added using a distributed, moving heat source. A sequentially coupled thermo-mechanical analysis is performed using a kinematic thermal model and a plane strain structural model. Temperature dependent material properties are used with the material modelled as elastic perfectly plastic. The material used is mild steel. The numerical results are checked against experimental data by manufacturing plate-shaped single layered specimens using an indigenously developed semi-automatic deposition system. The simulation results are compared with experimental data for successive sections along deposition and it is found that, with the exception of plate edges, the two are in very good agreement. The error at plate edges can be as high as 45% and the reason is that a 2D model cannot capture the effect of plate bolting accurately. The computational model is extended further to study the effects of various process parameters, like heat sink characteristics, rate of deposition and deposition sequence, on the buildup of residual stress and deformations. It has been observed that these parameters affect not only the magnitude of deformations but also its distribution. The residual stress distribution depends upon the sequence of deposition and the highest stresses are found at the last deposited row. In order to minimize distortions a proper combination of process parameters is essential.

  4. Analysis of the effects of processing parameters on mechanical properties and formability of cold rolled low carbon steel sheets using neural networks

    Microsoft Academic Search

    H. Monajati; D. Asefi; A. Parsapour; Sh. Abbasi

    2010-01-01

    In the present study, an artificial neural network (ANN) is used to describe the effects of processing parameters on the evolution of mechanical properties and formability of deep drawing quality (DDQ) steel sheets. This model is a feed forward back-propagation neural network (BPNN) with a set of 19 parameters including chemical composition, hot and cold rolling parameters, and subsequent batch

  5. Five-parameter grain boundary analysis by 3D EBSD of an ultra fine grained CuZr alloy processed by equal channel angular pressing

    E-print Network

    Rohrer, Gregory S.

    Five-parameter grain boundary analysis by 3D EBSD of an ultra fine grained CuZr alloy processed boundaries vary in a five-dimensional parameter space as a function of misorientation (3 variables) and grain materials. The five-parameter GBCD specifies the fractions of interface area sections, classified according

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

    USGS Publications Warehouse

    Barth, G.; Hill, M.C.

    2005-01-01

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

  7. Hyperspectral Data Processing and Mapping of Soil Parameters: Preliminary Data from Tuscany (Italy)

    NASA Astrophysics Data System (ADS)

    Garfagnoli, F.; Moretti, S.; Catani, F.; Innocenti, L.; Chiarantini, L.

    2010-12-01

    Hyperspectral imaging has become a very powerful remote sensing tool for its capability of performing chemical and physical analysis of the observed areas. The objective of this study is to retrieve and characterize clay mineral content of the cultivated layer of soils, from both airborne hyperspectral and field spectrometry surveys in the 400-2500 nm spectral range. Correlation analysis is used to examine the possibility to predict the selected property using high-resolution reflectance spectra and images. The study area is located in the Mugello basin, about 30 km north of Firenze (Tuscany, Italy). Agriculturally suitable terrains are assigned mainly to annual crops, marginally to olive groves, vineyards and orchards. Soils mostly belong to Regosols and Cambisols orders. About 80 topsoil samples scattered all over the area were collected simultaneously with the flight of SIM.GA hyperspectral camera from Selex Galileo. The quantitative determination of clay minerals content in soil samples was performed by means of XRD and Rietveld refinement. An ASD FieldSpec spectroradiometer was used to obtain reflectance spectra from dried, crushed and sieved samples under controlled laboratory conditions. Different chemometric techniques (multiple linear regression, vertex component analysis, partial least squares regression and band depth analysis) were preliminarily tested to correlate mineralogical records with reflectance data. A one component partial least squares regression model yielded a preliminary R2 value of 0.65. A similar result was achieved by plotting the absorption peak depth at 2210 versus total clay mineral content (band-depth analysis). A complete hyperspectral geocoded reflectance dataset was collected using SIM.GA hyperspectral image sensor from Selex-Galileo, mounted on board of the University of Firenze ultra light aircraft. The approximate pixel resolution was 0.6 m (VNIR) and 1.2 m (SWIR). Airborne SIM.GA row data were firstly transformed into at-sensor radiance values, where calibration coefficients and parameters from laboratory measurements are applied to non-georeferred VNIR/SWIR DN values. Then, geocoded products are retrieved for each flight line by using a procedure developed in IDL Language and PARGE (PARametric Geocoding) software. When all compensation parameters are applied to hyperspectral data or to the final thematic map, orthorectified, georeferred and coregistered VNIR to SWIR images or maps are available for GIS application and 3D view. Airborne imagery has to be corrected for the influence of the atmosphere, solar illumination, sensor viewing geometry and terrain geometry information, for the retrieval of inherent surface reflectance properties. Then, different geophysical parameters can be investigated and retrieved by means of inversion algorithms. The experimental fitting of laboratory data on mineral content is used for airborne data inversion, whose results are in agreement with laboratory records, demonstrating the possibility to use this methodology for digital mapping of soil properties.

  8. High strength fasteners cold forged out of work hardening steel

    Microsoft Academic Search

    David C Goss

    2000-01-01

    When designing fasteners, engineers should choose materials and processes that provide the strength required for the application. And if the materials can be turned into a fastener using less manufacturing steps than traditional processes, then a company making these fasteners can save time and money. For instance, high strength bolts and screws are typically produced from annealed wire. The wire

  9. HYDROGEN EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF FORGED STAINLESS STEELS

    SciTech Connect

    Morgan, M

    2008-03-28

    The effect of hydrogen on the fracture toughness properties of Types 304L, 316L and 21-6-9 forged stainless steels was investigated. Fracture toughness samples were fabricated from forward-extruded forgings. Samples were uniformly saturated with hydrogen after exposure to hydrogen gas at 34 MPa or 69 and 623 K prior to testing. The fracture toughness properties were characterized by measuring the J-R behavior at ambient temperature in air. The results show that the hydrogen-charged steels have fracture toughness values that were about 50-60% of the values measured for the unexposed steels. The reduction in fracture toughness was accompanied by a change in fracture appearance. Both uncharged and hydrogen-charged samples failed by microvoid nucleation and coalescence, but the fracture surfaces of the hydrogen-charged steels had smaller microvoids. Type 316L stainless steel had the highest fracture toughness properties and the greatest resistance to hydrogen degradation.

  10. Preparation of hydroxyapatite nanoparticles by sol-gel method with optimum processing parameters

    NASA Astrophysics Data System (ADS)

    Yusoff, Yusriha Mohd; Salimi, Midhat Nabil Ahmad; Anuar, Adilah

    2015-05-01

    Many studies have been carried out in order to prepare hydroxyapatite (HAp) by various methods. In this study, we focused on the preparation of HAp nanoparticles by using sol-gel technique in which few parameters are optimized which were stirring rate, aging time and sintering temperature. HAp nanoparticles were prepared by using precursors of calcium nitrate tetrahydrate, Ca(NO3)2.4H2O and phosphorous pentoxide, P2O5. Both precursors are mixed in ethanol respectively before they were mixed together in which it formed a stable sol. Fourier transform infrared (FTIR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM) were used for its characterization in terms of functional group, phase composition, crystallite size and morphology of the nanoparticles produced. FTIR spectra showed that the functional groups that present in all five samples were corresponding to the formation of HAp. Besides, XRD shows that only one phase was formed which was hydroxyapatite. Meanwhile, SEM shows that the small particles combine together to form agglomeration.

  11. Exploring the effects of pulsed electric field processing parameters on polyacetylene extraction from carrot slices.

    PubMed

    Aguiló-Aguayo, Ingrid; Abreu, Corina; Hossain, Mohammad B; Altisent, Rosa; Brunton, Nigel; Viñas, Inmaculada; Rai, Dilip K

    2015-01-01

    The effects of various pulsed electric field (PEF) parameters on the extraction of polyacetylenes from carrot slices were investigated. Optimised conditions with regard to electric field strength (1-4 kV/cm), number of pulses (100-1500), pulse frequency (10-200 Hz) and pulse width (10-30 ?s) were identified using response surface methodology (RSM) to maximise the extraction of falcarinol (FaOH), falcarindiol (FaDOH) and falcarindiol-3-acetate (FaDOAc) from carrot slices. Data obtained from RSM and experiments fitted significantly (p < 0.0001) the proposed second-order response functions with high regression coefficients (R2) ranging from 0.82 to 0.75. Maximal FaOH (188%), FaDOH (164.9%) and FaDOAc (166.8%) levels relative to untreated samples were obtained from carrot slices after applying PEF treatments at 4 kV/cm with 100 number of pulses of 10 ?s at 10 Hz. The predicted values from the developed quadratic polynomial equation were in close agreement with the actual experimental values with low average mean deviations (E%) ranging from 0.68% to 3.58%. PMID:25738537

  12. Stabilization of IgG by supercritical fluid drying: optimization of formulation and process parameters.

    PubMed

    Jovanovi?, Natasa; Bouchard, Andréanne; Hofland, Gerard W; Witkamp, Geert-Jan; Crommelin, Daan J A; Jiskoot, Wim

    2008-02-01

    The aim of this study was to stabilize human serum immunoglobulin G (IgG) by a supercritical fluid (SCF) drying process. Solutions containing IgG (20mg/ml) and trehalose or hydroxypropyl-beta-cyclodextrin in a 1:4 (w/w) ratio were sprayed into a SCF phase consisting of CO(2) and ethanol at 100bar and 37 degrees C. Initially, a set of drying conditions previously developed to successfully stabilize lysozyme and myogobin formulations was used [N. Jovanovi?, A. Bouchard, G.W. Hofland, G.J. Witkamp, D.J.A. Crommelin, W. Jiskoot, Eur. J. Pharm. Sci. 27 (2006) 336-345]. Dried formulations were analyzed by Karl Fisher titration, scanning electron microscopy, X-ray powder diffraction, and modulated DSC. Protein structure in the solid-state was studied by FTIR and after reconstitution by UV/Vis, circular dichroism and fluorescence spectroscopy, GPC and SDS-PAGE. When IgG was dried under the above-mentioned conditions, substantial amounts of insoluble aggregates were formed. Addition of buffer helped to reduce the fraction of insoluble material but not of soluble aggregates. Full stabilization could be achieved by adjusting the process conditions: drying without ethanol while keeping the other conditions the same, or drying with ethanol at a temperature below the critical point (20 degrees C). In conclusion, it is possible to stabilize human IgG by SCF drying provided that the formulation and process conditions are tailored to meet the specific requirements of the protein. PMID:17574824

  13. Effect of Breadmaking Process on In Vitro Gut Microbiota Parameters in Irritable Bowel Syndrome

    PubMed Central

    Costabile, Adele; Santarelli, Sara; Claus, Sandrine P.; Sanderson, Jeremy; Hudspith, Barry N.; Brostoff, Jonathan; Ward, Jane L.; Lovegrove, Alison; Shewry, Peter R.; Jones, Hannah E.; Whitley, Andrew M.; Gibson, Glenn R.

    2014-01-01

    A variety of foods have been implicated in symptoms of patients with Irritable Bowel Syndrome (IBS) but wheat products are most frequently cited by patients as a trigger. Our aim was to investigate the effects of breads, which were fermented for different lengths of time, on the colonic microbiota using in vitro batch culture experiments. A set of in vitro anaerobic culture systems were run over a period of 24 h using faeces from 3 different IBS donors (Rome Criteria–mainly constipated) and 3 healthy donors. Changes in gut microbiota during a time course were identified by fluorescence in situ hybridisation (FISH), whilst the small -molecular weight metabolomic profile was determined by NMR analysis. Gas production was separately investigated in non pH-controlled, 36 h batch culture experiments. Numbers of bifidobacteria were higher in healthy subjects compared to IBS donors. In addition, the healthy donors showed a significant increase in bifidobacteria (P<0.005) after 8 h of fermentation of a bread produced using a sourdough process (type C) compared to breads produced with commercial yeasted dough (type B) and no time fermentation (Chorleywood Breadmaking process) (type A). A significant decrease of ?-Proteobacteria and most Gemmatimonadetes species was observed after 24 h fermentation of type C bread in both IBS and healthy donors. In general, IBS donors showed higher rates of gas production compared to healthy donors. Rates of gas production for type A and conventional long fermentation (type B) breads were almost identical in IBS and healthy donors. Sourdough bread produced significantly lower cumulative gas after 15 h fermentation as compared to type A and B breads in IBS donors but not in the healthy controls. In conclusion, breads fermented by the traditional long fermentation and sourdough are less likely to lead to IBS symptoms compared to bread made using the Chorleywood Breadmaking Process. PMID:25356771

  14. A probabilistic approach to determine thermal process setting parameters: application for commercial sterility of products.

    PubMed

    Membré, Jeanne-Marie; van Zuijlen, André

    2011-01-01

    The objective of the probabilistic data analysis presented in this paper was to enable the thermal process to be set on actual data rather than on generic or conservative rules. The application was an ambient stable soup product, heated in a continuous UHT line. The data set comes from a decade of microbiological analysis: initial spore load and survival spore concentration after moderate heat-treatment (100°C for 15 min and 110°C for 15 min) have been enumerated in forty eight ingredients. The probabilistic analysis was carried out within a risk-based context, considering a Performance Objective, PO, set after the heat-treatment process and an initial spore contamination (H?) at the ingredient mixing step. The probabilistic analysis was based upon Bayesian inference, chosen for its flexibility when dealing with censored data (some values were reported as less than 1 log cfu/g) and also for its ability to incorporate in the data analysis prior information. Beforehand, Z values around 10°C for aerobic bacterial spores, and log count error around 1 log, were assumed. The methodology and the results are reported using two ingredients (garlic and milk powder) illustrating the 'not detected' (censored data) issue and also the inter-ingredient variability. Indeed, Z was estimated to be 13.6°C (mean) for spores selected from garlic and 5.9°C for those selected from milk powder. Based upon a hypothetical soup recipe with these two ingredients, the sterilization value was estimated to be 13 min (95th percentile). The potential use of similar methodology to design and set the sterilization value for the thermal process of future products, is discussed. PMID:21111502

  15. Processing and flammability parameters of bismaleimide and some other thermally stable resin matrices for composites

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.

    1984-01-01

    The effect of processing variables on the flammability and mechanical properties of state-of-the-art and advanced resin matrices for graphite composites were studied. Resin matrices which were evaluated included state-of-the-art epoxy, phenolic-novolac, phenolic-Xylok, two types of bismaleimides, benzyl, polyethersulfone, and polyphenylsulfone. Comparable flammability and thermochemical data on graphite-reinforced laminates prepared with these resin matrices are presented, and the relationship of some of these properties to the anaerobic char yield of the resins is described.

  16. Inverse problem to constrain the controlling parameters of large-scale heat transport processes: The Tiberias Basin example

    NASA Astrophysics Data System (ADS)

    Goretzki, Nora; Inbar, Nimrod; Siebert, Christian; Möller, Peter; Rosenthal, Eliyahu; Schneider, Michael; Magri, Fabien

    2015-04-01

    Salty and thermal springs exist along the lakeshore of the Sea of Galilee, which covers most of the Tiberias Basin (TB) in the northern Jordan- Dead Sea Transform, Israel/Jordan. As it is the only freshwater reservoir of the entire area, it is important to study the salinisation processes that pollute the lake. Simulations of thermohaline flow along a 35 km NW-SE profile show that meteoric and relic brines are flushed by the regional flow from the surrounding heights and thermally induced groundwater flow within the faults (Magri et al., 2015). Several model runs with trial and error were necessary to calibrate the hydraulic conductivity of both faults and major aquifers in order to fit temperature logs and spring salinity. It turned out that the hydraulic conductivity of the faults ranges between 30 and 140 m/yr whereas the hydraulic conductivity of the Upper Cenomanian aquifer is as high as 200 m/yr. However, large-scale transport processes are also dependent on other physical parameters such as thermal conductivity, porosity and fluid thermal expansion coefficient, which are hardly known. Here, inverse problems (IP) are solved along the NW-SE profile to better constrain the physical parameters (a) hydraulic conductivity, (b) thermal conductivity and (c) thermal expansion coefficient. The PEST code (Doherty, 2010) is applied via the graphical interface FePEST in FEFLOW (Diersch, 2014). The results show that both thermal and hydraulic conductivity are consistent with the values determined with the trial and error calibrations. Besides being an automatic approach that speeds up the calibration process, the IP allows to cover a wide range of parameter values, providing additional solutions not found with the trial and error method. Our study shows that geothermal systems like TB are more comprehensively understood when inverse models are applied to constrain coupled fluid flow processes over large spatial scales. References Diersch, H.-J.G., 2014. FEFLOW Finite Element Modeling of Flow, Mass and Heat Transport in Porous and Fractured Media. Springer- Verlag Berlin Heidelberg ,996p. Doherty J., 2010, PEST: Model-Independent Parameter Estimation. user manual 5th Edition. Watermark, Brisbane, Australia Magri, F., Inbar, N., Siebert C., Rosenthal, E., Guttman, J., Möller, P., 2015. Transient simulations of large-scale hydrogeological processes causing temperature and salinity anomalies in the Tiberias Basin. Journal of Hydrology, 520(0), 342-355.

  17. Process Model for Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Adams, Glynn

    1996-01-01

    Friction stir welding (FSW) is a relatively new process being applied for joining of metal alloys. The process was initially developed by The Welding Institute (TWI) in Cambridge, UK. The FSW process is being investigated at NASA/MSEC as a repair/initial weld procedure for fabrication of the super-light-weight aluminum-lithium shuttle external tank. The FSW investigations at MSFC were conducted on a horizontal mill to produce butt welds of flat plate material. The weldment plates are butted together and fixed to a backing plate on the mill bed. A pin tool is placed into the tool holder of the mill spindle and rotated at approximately 400 rpm. The pin tool is then plunged into the plates such that the center of the probe lies at, one end of the line of contact, between the plates and the shoulder of the pin tool penetrates the top surface of the weldment. The weld is produced by traversing the tool along the line of contact between the plates. A lead angle allows the leading edge of the shoulder to remain above the top surface of the plate. The work presented here is the first attempt at modeling a complex phenomenon. The mechanical aspects of conducting the weld process are easily defined and the process itself is controlled by relatively few input parameters. However, in the region of the weld, plasticizing and forging of the parent material occurs. These are difficult processes to model. The model presented here addresses only variations in the radial dimension outward from the pin tool axis. Examinations of the grain structure of the weld reveal that a considerable amount of material deformation also occurs in the direction parallel to the pin tool axis of rotation, through the material thickness. In addition, measurements of the axial load on the pin tool demonstrate that the forging affect of the pin tool shoulder is an important process phenomenon. Therefore, the model needs to be expanded to account for the deformations through the material thickness and the forging affect of the shoulder. The energy balance at the boundary of the plastic region with the environment required that energy flow away from the boundary in both radial directions. One resolution to this problem may be to introduce a time dependency into the process model, allowing the energy flow to oscillate across this boundary. Finally, experimental measurements are needed to verify the concepts used here and to aid in improving the model.

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  19. Evaluation of 3D printing for dies in low volume forging of 7075 aluminum helicopter parts

    Microsoft Academic Search

    R. Shivpuri; X. Cheng; K. Agarwal; S. Babu

    2005-01-01

    Purpose – To investigate the ProMetal 3D printing technique for its application to dies, for low volume hot forging of 7075 aluminum helicopter parts. Design\\/methodology\\/approach – Thermo-mechanical and tribological behavior of the ProMetal 3D printed tools were characterized by hot upset and ring tests. Finite element simulations of the test application were conducted using special purpose metal forming simulation software

  20. Innovative Die Material and Lubrication Strategies for Clean and Energy Conserving Forging Technologies

    SciTech Connect

    Rajiv Shivpuri; Sailesh Babu; Lin Yang; Yijun Zhu

    2007-01-08

    The objective of this project was to develop and implement innovative die material and surface coating strategies such as composite dies and lubricated coatings to increase die lives and to reduce environmental pollution. In this project approaches and software were developed for die life optimization and optimal design of lubrication systems for hot forging. In addition, LENS applied nickel-aluminide coatings were developed and validated in the industrial environment for significant improvements in die life.

  1. Computer-Aided FE Simulation for Flashless Cold Forging of Connecting Rod Without Underfilling

    Microsoft Academic Search

    H. M. T. Khaleed; Z. Samad; A. R. Othman; M. Abdul Mujeebu; A. Badarudin; A. B. Abdullah; A. R. Ab-Kadir; Irfan Anjum Badruddin; N. J. Salman Ahmed

    In this work, computer-aided finite element analysis to determine conditions for flashless cold forging of a connecting rod\\u000a is presented. The workpiece specifications were calculated by developing mathematical relations between the volumes of the\\u000a die cavity and workpiece. The three dimensional FE simulation was made using DEFORM-F3 V 6.0 and geometrical modeling of the\\u000a die and workpiece was performed with

  2. A 3D rigid–viscoplastic FEM simulation of compressor blade isothermal forging

    Microsoft Academic Search

    Mei Zhan; Yuli Liu; He Yang

    2001-01-01

    Based on the rigid–viscoplastic principle, three-dimensional finite element simulation using the penalty function was performed for the isothermal forging of a compressor blade. The key technologies of 3D rigid–viscoplastic FEM simulation are introduced. The workpiece was discretized into eight-node hexahedral isoparameteric elements and the die cavity was discretized into triangular elements. The methods proposed by the authors to remesh the

  3. A new method of preform design in hot forging by using electric field theory

    Microsoft Academic Search

    S. R. Lee; Y. K. Lee; C. H. Park; D. Y. Yang

    2002-01-01

    The preform design in metal forging plays a key role in improving product quality, such as ensuring defect-free property and proper metal flow. In industry, preforms are generally designed by the iterative trial-and-error approach. This approach, however, leads not only to the increase of significant tool cost but also to the extended down-time of the production equipment. It is thus

  4. Warm forging: new forming sequence for the manufacturing of long flat pieces

    Microsoft Academic Search

    B.-A. Behrens; P. Suchmann; A. Schott

    2008-01-01

    Warm forming of steel is an economic and ecologic alternative to the conventional hot forging technology. It offers several\\u000a advantages like decreased energy input, reduced scale formation, better surface quality and closer tolerances. Warm forming\\u000a is common for rotation symmetric parts but has not been applied for long flat pieces yet. The main obstacles prohibiting the\\u000a transfer are the missing

  5. Grain Orientation and Electrical Properties of Hot-Forged Bi4Ti3O12 Ceramics

    Microsoft Academic Search

    Tadashi Takenaka; Koichiro Sakata

    1980-01-01

    The effect of grain orientation on the dielectric properties of hot-forged ferroelectric Bi4Ti3O12 ceramics has been investigated and the properties are compared with ordinarily fired ones. The degree of grain orientation f calculated from X-ray diffraction patterns is found to be as large as 0.95. The temperature dependences of the dielectric constant \\\\varepsilons and loss tangent tan delta are measured

  6. Application of nimonic 80A to the hot forging of an exhaust valve head

    Microsoft Academic Search

    Dong Kwon Kim; Dong Young Kim; Seog Hyeon Ryu; Dong Jin Kim

    2001-01-01

    Nimonic 80A superalloy with high-temperature strength and high-corrosion resistance is used in jet engines for aircraft, gas turbines for power plant and marine diesel engines, etc. To set favorable hot forging conditions of Nimonic 80A, various mechanical tests such as the hot compression test and the micro-Vicker’s hardness test have been performed under various test conditions. The hardness during hot

  7. [Effect of critical process parameters on luminescence properties of Eu2+/Dy3+ co-doped high silica luminescence glass].

    PubMed

    Jin, Lei; Lei, Xiao-Hua; Ren, Lin-Jiao; Feng, Yong-An; Du, Xiao-Qing; Chen, Wei-Min

    2014-01-01

    In the present work, Eu2+/Dy3+ co-doped high silica glasses with different process parameters were prepared and the effect of critical process parameters including phase separation temperature, solution concentration and sintering temperature on the luminescence properties of Eu2+/Dy3+ co-doped high silica glasses was investigated by means of measuring pore surface parameters of porous glasses, emission spectra, infrared absorption spectra and densities of high silica glasses. Pore structure parameters of porous glass samples and emission spectra of corresponding high silica glass samples with different phase separation temperatures show that the phase separation temperature has indirect effect on luminescence properties of high silica glass by influencing specific surface area value of corresponding porous glass. Specific surface area of porous glass changes when phase separation temperature changes. High silica glass achieves maximum emission intensity when the maximum specific surface area of porous glass is obtained. Luminescence intensity of high silica glass increases when specific surface area of porous glass increases. Emission spectra of high silica glass samples with different solution concentrations show that the emission intensities of Eu2+ and Dy3+ in high silica glass are enhanced with the increase in the Dy3+ concentration in solution; when the Dy3+ concentration is beyond 0.1 mol x L(-1), the emission intensities of Eu2+ and Dy3+ in high silica glass are both decreased due to the occurring of concentration quench of Dy3+ in the glass. Emission spectra and infrared absorption spectra of high silica glass samples with different sintering temperatures show that the emission intensity of high silica glass is increased with the increase in the sintering temperature because the content of residual hydroxyl groups -OH in the glass is decreased; when the sintering temperature is beyond 1000 degrees C, the high silica glass exhibits crystalline and the luminescence intensity decreases. PMID:24783528

  8. Optimization of Processing Parameters in ECM of Die Tool Steel Using Nanofluid by Multiobjective Genetic Algorithm

    PubMed Central

    Sathiyamoorthy, V.; Sekar, T.; Elango, N.

    2015-01-01

    Formation of spikes prevents achievement of the better material removal rate (MRR) and surface finish while using plain NaNO3 aqueous electrolyte in electrochemical machining (ECM) of die tool steel. Hence this research work attempts to minimize the formation of spikes in the selected workpiece of high carbon high chromium die tool steel using copper nanoparticles suspended in NaNO3 aqueous electrolyte, that is, nanofluid. The selected influencing parameters are applied voltage and electrolyte discharge rate with three levels and tool feed rate with four levels. Thirty-six experiments were designed using Design Expert 7.0 software and optimization was done using multiobjective genetic algorithm (MOGA). This tool identified the best possible combination for achieving the better MRR and surface roughness. The results reveal that voltage of 18?V, tool feed rate of 0.54?mm/min, and nanofluid discharge rate of 12?lit/min would be the optimum values in ECM of HCHCr die tool steel. For checking the optimality obtained from the MOGA in MATLAB software, the maximum MRR of 375.78277?mm3/min and respective surface roughness Ra of 2.339779??m were predicted at applied voltage of 17.688986?V, tool feed rate of 0.5399705?mm/min, and nanofluid discharge rate of 11.998816?lit/min. Confirmatory tests showed that the actual performance at the optimum conditions was 361.214?mm3/min and 2.41??m; the deviation from the predicted performance is less than 4% which proves the composite desirability of the developed models. PMID:26167538

  9. HOW CAN STFC HELP? STFC proactively forges links with

    E-print Network

    to identify the atomic- scale differences between materials processed under identical conditions, but which sectors: · Energy · Environmental · Healthcare · Chemical · Biochemical · Security · Advanced Engineering · Automotive · Aerospace The assistance available would be provided as redeemable vouchers worth up to £4

  10. Grain Size Estimation of Superalloy Inconel 718 After Upset Forging by a Fuzzy Inference System

    NASA Astrophysics Data System (ADS)

    Toro, Luis; Cavazos, Alberto; Colás, Rafael

    2009-12-01

    A fuzzy logic inference system was designed to predict the grain size of Inconel 718 alloy after upset forging. The system takes as input the original grain size, temperature, and reduction rate at forging and predicts the final grain size at room temperature. It is assumed that the system takes into account the effects that the heterogeneity of deformation and grain growth exerts in this particular material. Experimental trials were conducted in a factory that relies on upset forging to produce preforms for ring rolling. The grain size was reported as ASTM number, as this value is used on site. A first attempt was carried out using a series of 15 empirically based set of rules; the estimation error with these was above two ASTM numbers; which is considered to be very high. The system was modified and expanded to take into account 28 rules; the estimation error of this new system resulted to be close to one ASTM number, which is considered to be adequate for the prediction.

  11. Current forgings and their properties for steam generator of nuclear plant

    SciTech Connect

    Tsukada, Hisashi; Suzuki, Komei; Kusuhashi, Mikio; Sato, Ikuo [Japan Steel Works Ltd., Muroran (Japan)

    1997-12-31

    Current steel forgings for steam generator (SG) of PWR plant are reviewed in the aspect of design and material improvement. The following three items are introduced. The use of integral type steel forgings for the fabrication of steam generator enhances the structural integrity and makes easier fabrication and inspection including in-service inspection. The following examples of current integral type forgings developed by the Japan Steel Works, Ltd. (JSW) are introduced: (1) primary head integrated with nozzles, manways and supports; (2) steam drum head integrated with nozzle and handhole; (3) conical shell integrated with cylindrical sections and handholes. In order to decrease the weight of steam generator, the high strength materials such as SA508, Cl.3a steel have been adopted in some cases. The properties of this steel are introduced and the chemistry and heat treatment condition are discussed. As one of the methods to minimize the macro- and micro-segregations, the use of vacuum carbon deoxidation (VCD), i.e. deoxidization of steel by gaseous CO reaction, with addition of Al for grain refining was investigated. The properties of SA508, Cl.3 steels with Low Si content are compared with those of conventional one.

  12. Microstructure and degradation behavior of forged Fe-Mn-Si alloys

    NASA Astrophysics Data System (ADS)

    Xu, Zhigang; Hodgson, Michael A.; Cao, Peng

    2015-03-01

    This work presents a comparative study of a series of Fe-Mn-Si alloys proposed as degradable biomaterials for medical applications. Five Fe-28wt.%Mn-xSi (where x = 0 to 8 wt.%) alloys were fabricated by an arc-melting method. All the as-cast alloys were subsequently subjected to homogenization treatment and hot forging. The microstructure and phase constituents were investigated. It is found that the grain size of the as-forged alloys ranged approximately from 30 to 50 ?m. The as-forged Fe-Mn-Si alloys containing Si from 2 to 6 wt.% was comprised of duplex martensitic ? and austenitic ? phases; however, the Si-free and 8 wt.% Si alloys only consisted of a single ? phase. After 30 days of static immersion test in a simulated body fluid (SBF) medium, it is found that pitting and general corrosion occur on the sample surfaces. Potentiodynamic analysis reveals that the degradation rate of the Fe-Mn-Si alloys increased gradually with Si content up to 6 wt.%, beyond which the degradation slows down.

  13. Continuous-wave fiber laser cutting of aluminum thin sheets: effect of process parameters and optimization

    NASA Astrophysics Data System (ADS)

    Scintilla, Leonardo Daniele

    2014-06-01

    One-millimeter-thick Al 1050 sheets were cut using a 2-kW fiber laser operating in continuous-wave (CW) mode. An experimental approach that consisted of fitting the regression models by means of response surface methodology was adopted. The effects of cutting speed, assist gas pressure, and focal position on roughness arithmetic mean value were investigated. The desirability function was applied for the simultaneous optimization of cut quality and operating costs. The full potential of the CW mode high processing speeds and of the better absorptivity of 1-?m laser radiation for highly reflective materials are employed at the same time. Cutting aluminum with fiber laser increases the cutting speed and gives a cut quality comparable with results obtained with CO2 and Nd:YAG lasers that represent the most established laser sources for this application.

  14. Characteristic parameters in combustion processes and their accessibility to current and future diagnostics. Annual report

    SciTech Connect

    Goulard, R.

    1980-05-01

    A review of current combustion research shows a growing awareness of the potential offered by the new high speed three-dimensional techniques. Some of the recent advances in the fluid dynamics of jet mixing are discussed, with an emphasis on the 10 kHz range (especially vortex shedding). Also the very fast subnanosecond range of radical kinetics is investigated, as well as the comparably fast scattering and fluorescence processes. High speed diagnostics are discussed in these two ranges of time resolution, with an emphasis on optical tomography for the fluid dynamic time range (10/sup -4/ s) and on picosecond techniques for the physical chemistry range (10/sup -9/ s). This work was carried out during the period June 1, 1979 to May 31, 1980.

  15. The effect of GASAR processing parameters on porosity and properties in aluminum alloy

    SciTech Connect

    Paradies, C.J.; Tobin, A. [Northrop Grumman Corp., Bethpage, NY (United States); Wolla, J. [Naval Research Lab., Washington, DC (United States)

    1998-12-31

    The GASAR process involves the dissolution of hydrogen in a molten metal or alloy by controlling the hydrogen pressure and the temperature in a high pressure chamber. The difference between the hydrogen solubility in the melt and the solid is used to control the growth of hydrogen pores within the solidifying structure. Designed experiments have been performed to determine the relative effects of the saturation pressure, temperature, casting pressure, mold temperature and cooling rate on the total porosity, pore size, distribution and shape in pure nickel and aluminum alloys. The shape and distribution of pores was found to depend upon the structure of the primary solid pore nucleation and growth. Reducing the casting pressure had the strongest effect on increasing the total porosity and pore size.

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

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

    PubMed Central

    Belwalkar, A.; Grasing, E.; Huang, Z.; Misiolek, W.Z.

    2008-01-01

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

  19. Digital signal processing using lapped transforms with variable parameter windows and orthonormal bases

    NASA Astrophysics Data System (ADS)

    Raduenz, Brian D.

    1992-12-01

    A number of new concepts and tools for the analysis of signals using variable overlapped windows and orthonormal bases are developed and evaluated. Windowing, often employed as a spectral estimation technique, can result in irreparable distortions in the transformed signal. By placing conditions on the window and incorporating it into the orthonormal representation, any signal distortion resulting from the transformation can be eliminated or cancelled in reconstruction. This concept is critical to the theory discussed. As part of this evaluation, a tensor product based general N-point fast Fourier transform algorithm was implemented in the DOD standard language, Ada. The most prevalent criticism of Ada is slow execution time. This code is shown to be comparable in execution time performance to the corresponding FORTRAN code. Also, a new paradigm is presented for solving the finite length data problem associated with filter banks and lapped transforms. This result could have significant importance in many Air Force applications, such as processing images in which the objects of interest are near the borders. Additionally, a limited number of experiments were performed with the coding of speech. The results indicate the lapped transform evaluated has potential as a low bit rate speech coder.

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

    PubMed

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

    2008-07-01

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

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

    PubMed

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Rahimipour, Mohammad Reza; Sobhani, Manoochehr

    2013-10-01

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

  3. Regional assessment of boreal forest productivity using an ecological process model and remote sensing parameter maps.

    PubMed

    Kimball, J. S.; Keyser, A. R.; Running, S. W.; Saatchi, S. S.

    2000-06-01

    An ecological process model (BIOME-BGC) was used to assess boreal forest regional net primary production (NPP) and response to short-term, year-to-year weather fluctuations based on spatially explicit, land cover and biomass maps derived by radar remote sensing, as well as soil, terrain and daily weather information. Simulations were conducted at a 30-m spatial resolution, over a 1205 km(2) portion of the BOREAS Southern Study Area of central Saskatchewan, Canada, over a 3-year period (1994-1996). Simulations of NPP for the study region were spatially and temporally complex, averaging 2.2 (+/- 0.6), 1.8 (+/- 0.5) and 1.7 (+/- 0.5) Mg C ha(-1) year(-1) for 1994, 1995 and 1996, respectively. Spatial variability of NPP was strongly controlled by the amount of aboveground biomass, particularly photosynthetic leaf area, whereas biophysical differences between broadleaf deciduous and evergreen coniferous vegetation were of secondary importance. Simulations of NPP were strongly sensitive to year-to-year variations in seasonal weather patterns, which influenced the timing of spring thaw and deciduous bud-burst. Reductions in annual NPP of approximately 17 and 22% for 1995 and 1996, respectively, were attributed to 3- and 5-week delays in spring thaw relative to 1994. Boreal forest stands with greater proportions of deciduous vegetation were more sensitive to the timing of spring thaw than evergreen coniferous stands. Similar relationships were found by comparing simulated snow depth records with 10-year records of aboveground NPP measurements obtained from biomass harvest plots within the BOREAS region. These results highlight the importance of sub-grid scale land cover complexity in controlling boreal forest regional productivity, the dynamic response of the biome to short-term interannual climate variations, and the potential implications of climate change and other large-scale disturbances. PMID:12651512

  4. Breath-by-breath pulmonary O2 uptake kinetics: effect of data processing on confidence in estimating model parameters.

    PubMed

    Keir, Daniel A; Murias, Juan M; Paterson, Donald H; Kowalchuk, John M

    2014-11-01

    To improve the signal-to-noise ratio of breath-by-breath pulmonary O2 uptake (V?O2p) data, it is common practice to perform multiple step transitions, which are subsequently processed to yield an ensemble-averaged profile. The effect of different data-processing techniques on phase II V?O2p kinetic parameter estimates (V?O2p amplitude, time delay and phase II time constant (?V?O2p)] and model confidence [95% confidence interval (CI95)] was examined. Young (n = 9) and older men (n = 9) performed four step transitions from a 20 W baseline to a work rate corresponding to 90% of their estimated lactate threshold on a cycle ergometer. Breath-by-breath V?O2p was measured using mass spectrometry and volume turbine. Mono-exponential kinetic modelling of phase II V?O2p data was performed on data processed using the following techniques: (A) raw data (trials time aligned, breaths of all trials combined and sorted in time); (B) raw data plus interpolation (trials time aligned, combined, sorted and linearly interpolated to second by second); (C) raw data plus interpolation plus 5 s bin averaged; (D) individual trial interpolation plus ensemble averaged [trials time aligned, linearly interpolated to second by second (technique 1; points joined by straight-line segments), ensemble averaged]; (E) 'D' plus 5 s bin averaged; (F) individual trial interpolation plus ensemble averaged [trials time aligned, linearly interpolated to second by second (technique 2; points copied until subsequent point appears), ensemble averaged]; and (G) 'F' plus 5 s bin averaged. All of the model parameters were unaffected by data-processing technique; however, the CI95 for ?V?O2p in condition 'D' (4 s) was lower (P < 0.05) than the CI95 reported for all other conditions (5-10 s). Data-processing technique had no effect on parameter estimates of the phase II V?O2p response. However, the narrowest interval for CI95 occurred when individual trials were linearly interpolated and ensemble averaged. PMID:25063837

  5. Endosymbiotic gene transfer: organelle genomes forge eukaryotic chromosomes

    Microsoft Academic Search

    Michael A. Ayliffe; Chun Y. Huang; William Martin; Jeremy N. Timmis

    2004-01-01

    Genome sequences reveal that a deluge of DNA from organelles has constantly been bombarding the nucleus since the origin of organelles. Recent experiments have shown that DNA is transferred from organelles to the nucleus at frequencies that were previously unimaginable. Endosymbiotic gene transfer is a ubiquitous, continuing and natural process that pervades nuclear DNA dynamics. This relentless influx of organelle

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

    PubMed

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

    2014-04-01

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

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

    PubMed Central

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

    2014-01-01

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

  8. 3D Finite Element Analysis of the Effect of Process Parameters on Linear Friction Welding of Mild Steel

    NASA Astrophysics Data System (ADS)

    Li, Wenya; Wang, Feifan; Shi, Shanxiang; Ma, Tiejun; Li, Jinglong; Vairis, Achilleas

    2014-11-01

    In this work, a 3D numerical model was developed to investigate the complicated thermo-mechanically coupled process of linear friction welding (LFW). The explicit-implicit alternate method was adopted for the first time to simulate LFW mild steel based on the ABAQUS software. To cope with the excessive element distortion, remeshing was conducted at certain calculation time with the help of the HYPERWORKS software. Results show that the interface temperature is quickly increased to near 900 °C within 1 s. With increasing the welding time, the interface temperature reaches a quasi-steady state of about 950 °C and the axial shortening rate keeps almost constant. A final unilateral axial shortening of 2.73 mm was obtained under the experiment condition, which corresponds well to the experiment. Moreover, the effects of processing parameters (oscillation frequency, oscillation amplitude, and friction pressure) on the joint temperature evolution and axial shortening were systematically examined and discussed. These three parameters could be integrated into one factor, i.e., heat input to the interface.

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

    PubMed

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

    2014-01-01

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

  10. Contact-free determination of human body segment parameters by means of videometric image processing of an anthropomorphic body model

    NASA Astrophysics Data System (ADS)

    Hatze, Herbert; Baca, Arnold

    1993-01-01

    The development of noninvasive techniques for the determination of biomechanical body segment parameters (volumes, masses, the three principal moments of inertia, the three local coordinates of the segmental mass centers, etc.) receives increasing attention from the medical sciences (e,.g., orthopaedic gait analysis), bioengineering, sport biomechanics, and the various space programs. In the present paper, a novel method is presented for determining body segment parameters rapidly and accurately. It is based on the video-image processing of four different body configurations and a finite mass-element human body model. The four video images of the subject in question are recorded against a black background, thus permitting the application of shape recognition procedures incorporating edge detection and calibration algorithms. In this way, a total of 181 object space dimensions of the subject's body segments can be reconstructed and used as anthropometric input data for the mathematical finite mass- element body model. The latter comprises 17 segments (abdomino-thoracic, head-neck, shoulders, upper arms, forearms, hands, abdomino-pelvic, thighs, lower legs, feet) and enables the user to compute all the required segment parameters for each of the 17 segments by means of the associated computer program. The hardware requirements are an IBM- compatible PC (1 MB memory) operating under MS-DOS or PC-DOS (Version 3.1 onwards) and incorporating a VGA-board with a feature connector for connecting it to a super video windows framegrabber board for which there must be available a 16-bit large slot. In addition, a VGA-monitor (50 - 70 Hz, horizontal scan rate at least 31.5 kHz), a common video camera and recorder, and a simple rectangular calibration frame are required. The advantage of the new method lies in its ease of application, its comparatively high accuracy, and in the rapid availability of the body segment parameters, which is particularly useful in clinical practice. An example of its practical application illustrates the technique.

  11. The Effect of Forging Variables on the Supersolvus Heat-Treatment Response of Powder-Metallurgy Nickel-Base Superalloys

    NASA Astrophysics Data System (ADS)

    Semiatin, S. L.; Shank, J. M.; Shiveley, A. R.; Saurber, W. M.; Gaussa, E. F.; Pilchak, A. L.

    2014-12-01

    The effect of subsolvus forging temperature and strain rate on the grain size developed during final supersolvus heat treatment (SSHT) of two powder-metallurgy, gamma-gamma prime superalloys, IN-100 and LSHR, was established. For this purpose, isothermal, hot compression tests were performed at temperatures ranging from 1144 K (871 °C) and 22 K (22 °C) below the respective gamma-prime solvus temperatures ( T ?') and strain rates between 0.0003 and 10 s-1. Deformed samples were then heat treated 20 K (20 °C) above the solvus for 1 h with selected additional samples exposed for shorter and longer times. For both alloys, the grain size developed during SSHT was in the range of 15 to 30 ?m, except for those processing conditions consisting of pre-deformation at the highest temperature, i.e., T ?'—22 K ( T ?'—22 °C), and strain rates in the range of ~0.001 to 0.1 s-1. In these latter instances, the heat-treated grain size was approx. four times as large. The observations were interpreted in terms of the mechanisms of deformation during hot working and their effect on the driving forces for grain-boundary migration which controls the evolution of the gamma-grain size.

  12. The Effect of Forging Variables on the Supersolvus Heat-Treatment Response of Powder-Metallurgy Nickel-Base Superalloys

    NASA Astrophysics Data System (ADS)

    Semiatin, S. L.; Shank, J. M.; Shiveley, A. R.; Saurber, W. M.; Gaussa, E. F.; Pilchak, A. L.

    2014-09-01

    The effect of subsolvus forging temperature and strain rate on the grain size developed during final supersolvus heat treatment (SSHT) of two powder-metallurgy, gamma-gamma prime superalloys, IN-100 and LSHR, was established. For this purpose, isothermal, hot compression tests were performed at temperatures ranging from 1144 K (871 °C) and 22 K (22 °C) below the respective gamma-prime solvus temperatures (T ?') and strain rates between 0.0003 and 10 s-1. Deformed samples were then heat treated 20 K (20 °C) above the solvus for 1 h with selected additional samples exposed for shorter and longer times. For both alloys, the grain size developed during SSHT was in the range of 15 to 30 ?m, except for those processing conditions consisting of pre-deformation at the highest temperature, i.e., T ?'—22 K (T ?'—22 °C), and strain rates in the range of ~0.001 to 0.1 s-1. In these latter instances, the heat-treated grain size was approx. four times as large. The observations were interpreted in terms of the mechanisms of deformation during hot working and their effect on the driving forces for grain-boundary migration which controls the evolution of the gamma-grain size.

  13. Encapsulation of immunoglobulin G by solid-in-oil-in-water: effect of process parameters on microsphere properties.

    PubMed

    Marquette, Sarah; Peerboom, Claude; Yates, Andrew; Denis, Laurence; Goole, Jonathan; Amighi, Karim

    2014-04-01

    Antibodies (Abs) are prone to a variety of physical and chemical degradation pathways, which require the development of stable formulations and specific delivery strategies. In this study, injectable biodegradable and biocompatible polymeric particles were employed for controlled-release dosage forms and the encapsulation of antibodies into polylactide-co-glycolide (PLGA) based microspheres was explored. In order to avoid stability issues which are commonly described when water-in-oil (w/o) emulsion is used, a solid-in-oil-in-water (s/o/w) method was developed and optimized. The solid phase was made of IgG microparticles and the s/o/w process was evaluated as an encapsulation method using a model Ab molecule (polyclonal bovine immunoglobulin G (IgG)). The methylene chloride (MC) commonly used for an encapsulation process was replaced by ethyl acetate (EtAc), which was considered as a more suitable organic solvent in terms of both environmental and human safety. The effects of several processes and formulation factors were evaluated on IgG:PLGA microsphere properties such as: particle size distribution, drug loading, IgG stability, and encapsulation efficiency (EE%). Several formulations and processing parameters were also statistically identified as critical to get reproducible process (e.g. the PLGA concentration, the volume of the external phase, the emulsification rate, and the quantity of IgG microparticles). The optimized encapsulation method has shown a drug loading of up to 6% (w/w) and an encapsulation efficiency of up to 60% (w/w) while preserving the integrity of the encapsulated antibody. The produced microspheres were characterized by a d(0.9) lower than 110 ?m and showed burst effect lower than 50% (w/w). PMID:24184674

  14. Modeling of Selected Ceramic Processing Parameters Employed in the Fabrication of 238PuO2 Fuel Pellets

    DOE PAGESBeta

    Brockman, R. A.; Kramer, Daniel P.; Barklay, Chadwick D.; Cairns-Gallimore, Dirk; Brown, J. L.; Huling, J. C.; van Pelt, C. E.

    2011-01-01

    Recent deep space missions utilize the thermal output of the radioisotope plutonium-238 as the fuel in the thermal to electrical power system. Since the application of plutonium in its elemental state has several disadvantages, the fuel employed in these deep space power systems is typically in the oxide form such as plutonium-238 dioxide (238PuO2). As an oxide, the processing of the plutonium dioxide into fuel pellets is performed via ''classical'' ceramic processing unit operations such as sieving of the powder, pressing, sintering, etc. Modeling of these unit operations can be beneficial in the understanding and control of processing parameters withmore »the goal of further enhancing the desired characteristics of the 238PuO2 fuel pellets. A finite element model has been used to help identify the time-temperature-stress profile within a pellet during a furnace operation taking into account that 238PuO2 itself has a significant thermal output. Results of the modeling efforts will be discussed.« less

  15. Modeling of Selected Ceramic Processing Parameters Employed in the Fabrication of 238PuO2 Fuel Pellets

    DOE PAGESBeta

    Brockman, R. A. [Univ. of Dayton, OH (United States); Kramer, Daniel P. [Univ. of Dayton, OH (United States); Barklay, Chadwick D. [Univ. of Dayton, OH (United States); Cairns-Gallimore, Dirk [U.S. Department of Energy, Germantown, MD (United States); Brown, J. L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Huling, J. C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); van Pelt, C. E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2011-01-01

    Recent deep space missions utilize the thermal output of the radioisotope plutonium-238 as the fuel in the thermal to electrical power system. Since the application of plutonium in its elemental state has several disadvantages, the fuel employed in these deep space power systems is typically in the oxide form such as plutonium-238 dioxide (238PuO2). As an oxide, the processing of the plutonium dioxide into fuel pellets is performed via ''classical'' ceramic processing unit operations such as sieving of the powder, pressing, sintering, etc. Modeling of these unit operations can be beneficial in the understanding and control of processing parameters with the goal of further enhancing the desired characteristics of the 238PuO2 fuel pellets. A finite element model has been used to help identify the time-temperature-stress profile within a pellet during a furnace operation taking into account that 238PuO2 itself has a significant thermal output. Results of the modeling efforts will be discussed.

  16. Forging an Agenda for Suicide Prevention in the United States

    PubMed Central

    2013-01-01

    Suicide prevention must be transformed by integrating injury prevention and mental health perspectives to develop a mosaic of common risk public health interventions that address the diversity of populations and individuals whose mortality and morbidity contribute to the burdens of suicide and attempted suicide. Emphasizing distal preventive interventions, strategies must focus on people and places—and on related interpersonal factors and social contexts—to alter the life trajectories of people before they become suicidal. Attention also must be paid to those in the middle years—the age with the greatest overall burden. We need scientific and social processes that define priorities and assess their potential for reducing what has been a steadily increasing rate of suicide during the past decade. PMID:23488515

  17. Cr3C2-NiCr HVOF-Sprayed Coatings: Microstructure and Properties Versus Powder Characteristics and Process Parameters

    NASA Astrophysics Data System (ADS)

    Prudenziati, Maria; Gazzadi, Gian Carlo; Medici, Marcello; Dalbagni, Gregorio; Caliari, Marco

    2010-03-01

    Two 75%Cr3C2-25%NiCr feedstock powders with the same size distribution but different production process were characterized and found quite different in terms of morphology and phase composition. The powders were sprayed in a HVOF Diamond Jet (Sulzer Metco DJ-2600) torch with five different values of the oxygen-to-hydrogen ratio in order to assess the influence of this parameter on the microstructure and properties of the coatings. The results show that the closed and dense microstructure of one powder (Woka 7302) results in coatings with lower amount of decarburization, less oxide formation and higher toughness compared to coatings from the other powder (Praxair 1375). It was found that the O2/H2 ratio impacts mainly on the Young’s modulus, which almost doubled by changing the ratio from 0.40 to 0.50, and on toughness, but does not notably affect the Vickers hardness.

  18. Effect of extrusion process parameters and pregelatinized rice flour on physicochemical properties of ready-to-eat expanded snacks.

    PubMed

    Gat, Yogesh; Ananthanarayan, Laxmi

    2015-05-01

    Present study was conducted to investigate effects of pregelatinized rice flour and extrusion process parameters such as feed moisture (16-19 %), die temperature (115-145 °C) and screw speed (150-250 rpm) on physicochemical properties of ready-to-eat expanded snacks by using co-rotating twin-screw extruder. Higher die temperature increased extrudate density and WSI but reduced die pressure, torque and expansion. Increased feed moisture content resulted in extrudates with increased density, WAI and hardness but reduced die pressure, expansion and WSI. Screw speed was found to have no significant effect on expansion and hardness of extrudates, while increase in screw speed resulted in increased WAI of extrudates and reduced torque of extrudates. Effect of pregelatinized rice flour on extrudate expansion and hardness was analysed at 16 % feed moisture, 135 °C die temperature and 150 rpm screw speed. Use of pregelatinized rice flour increased expansion while it reduced hardness of extrudates. PMID:25892761

  19. Cutting Parameters Optimization and Constraints Investigation for Turning Process by GA with Self-Organizing Adaptive Penalty Strategy

    NASA Astrophysics Data System (ADS)

    Ahmad, Nafis; Tanaka, Tomohisa; Saito, Yoshio

    For efficient use of machine tools at optimum cutting condition, it is necessary to find a suitable optimization method, which can find optimum feasible solution rapidly and explain the constraints as well. As the actual turning process parameter optimization is highly constrained and nonlinear, a modified Genetic Algorithm with Self Organizing Adaptive Penalty (SOAP) strategy is used to find the optimum cutting condition and to get clear idea of constraints at the optimum condition. Unit production cost is the objective function while limits of the cutting force, power, surface finish, stability condition, tool-chip interface temperature and available rotational speed in the machine tool are considered as the constraints. The result shows that our approach of GA with SOAP converges quickly by focusing on the boundary of the feasible and infeasible solution space created by constraints and also identifies the critical and non-critical constraints at the optimum condition.

  20. Model parameters conditioning on regional hydrologic signatures for process-based design flood estimation in ungauged basins.

    NASA Astrophysics Data System (ADS)

    Biondi, Daniela; De Luca, Davide Luciano

    2015-04-01

    The use of rainfall-runoff models represents an alternative to statistical approaches (such as at-site or regional flood frequency analysis) for design flood estimation, and constitutes an answer to the increasing need for synthetic design hydrographs (SDHs) associated to a specific return period. However, the lack of streamflow observations and the consequent high uncertainty associated with parameter estimation, usually pose serious limitations to the use of process-based approaches in ungauged catchments, which in contrast represent the majority in practical applications. This work presents the application of a Bayesian procedure that, for a predefined rainfall-runoff model, allows for the assessment of posterior parameters distribution, using the limited and uncertain information available for the response of an ungauged catchment (Bulygina et al. 2009; 2011). The use of regional estimates of river flow statistics, interpreted as hydrological signatures that measure theoretically relevant system process behaviours (Gupta et al. 2008), within this framework represents a valuable option and has shown significant developments in recent literature to constrain the plausible model response and to reduce the uncertainty in ungauged basins. In this study we rely on the first three L-moments of annual streamflow maxima, for which regressions are available from previous studies (Biondi et al. 2012; Laio et al. 2011). The methodology was carried out for a catchment located in southern Italy, and used within a Monte Carlo scheme (MCs) considering both event-based and continuous simulation approaches for design flood estimation. The applied procedure offers promising perspectives to perform model calibration and uncertainty analysis in ungauged basins; moreover, in the context of design flood estimation, process-based methods coupled with MCs approach have the advantage of providing simulated floods uncertainty analysis that represents an asset in risk-based decision making and in hydraulic design. The obtained results highlight the relevant impact of uncertainty in regional estimates of hydrological signatures on posterior parameters distribution and on uncertainty bounds of simulated peak discharges. The results of the continuous simulation, generally, better matched those of the statistical flood frequency analysis, thus this approach is recommended for the flood frequency analysis in the study area. REFERENCES Biondi D, Claps P, Cruscomagno F, De Luca DL, Fiorentino M, Ganora D, Gioia A, Iacobellis V, Laio F, Manfreda S, Versace P (2012). Dopo il VAPI: la valutazione delle massime portate al colmo di piena nell'esperienza del POR Calabria (in Italian). Proceedings of XXXIII Italian National Conference on Hydraulics and Hydraulic Engineering, Brescia - Italy, 10-15 September 2012. Bulygina N, McIntyre N, Wheater HS (2009). Conditioning rainfall- runoff model parameters for ungauged catchments and land management impacts analysis. Hydrol Earth Syst Sci 13:893-904. doi:10.5194/hess-13-893-2009. Bulygina N, McIntyre N, Wheater H (2011). Bayesian conditioning of a rainfall-runoff model for predicting flows in ungauged catchments and under land use changes. Water Resour Res 47: W02503. doi:10.1029/2010WR009240. Gupta HV, Wagener T, Liu Y (2008). Reconciling theory with observations: elements of a diagnostic approach to model evaluation. Hydrol Process 22: 3802-3813. doi:10.1002/hyp.6989. Laio F, Ganora D, Claps P, Galeati G (2011). Spatially smooth regional estimation of the flood frequency curve (with uncertainty). J Hydrol 408: 67-77.