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Sample records for forging process parameters

  1. Optimum Design of Forging Process Parameters and Preform Shape under Uncertainties

    NASA Astrophysics Data System (ADS)

    Repalle, Jalaja; Grandhi, Ramana V.

    2004-06-01

    Forging is a highly complex non-linear process that is vulnerable to various uncertainties, such as variations in billet geometry, die temperature, material properties, workpiece and forging equipment positional errors and process parameters. A combination of these uncertainties could induce heavy manufacturing losses through premature die failure, final part geometric distortion and production risk. Identifying the sources of uncertainties, quantifying and controlling them will reduce risk in the manufacturing environment, which will minimize the overall cost of production. In this paper, various uncertainties that affect forging tool life and preform design are identified, and their cumulative effect on the forging process is evaluated. Since the forging process simulation is computationally intensive, the response surface approach is used to reduce time by establishing a relationship between the system performance and the critical process design parameters. Variability in system performance due to randomness in the parameters is computed by applying Monte Carlo Simulations (MCS) on generated Response Surface Models (RSM). Finally, a Robust Methodology is developed to optimize forging process parameters and preform shape. The developed method is demonstrated by applying it to an axisymmetric H-cross section disk forging to improve the product quality and robustness.

  2. Effects of processing parameters in P/M steel forging on part properties: A review part II forging of sintered compact

    NASA Astrophysics Data System (ADS)

    Duggirala, R.; Shivpuri, R.

    1992-08-01

    In the last decade, powder metallurgy (P/M) technology has made marked advances in competitive manufacturing. P/M offers design opportunities that are not possible with other methods, as well as significant cost savings. The processing parameters, material characteristics, individual stages of parts production, deformation and densification mechanics and tooling, and preform design influence the properties of the P/M part and related economics. Therefore, a review of the various parameters involved in the different stages of P/M steel forging in net-shape manufacturing and their implications on resulting properties of the P/M parts is presented in a three-part review. Part I discussed the issues of powder preparation, compaction, and sintering in the stages of preparing a sintered compact. This review (Part II) identifies key parameters in forging the sintered compact that influence the properties of the powder forged part. Part III reviews currently available analysis methods for studying the powder forging process.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  4. Large forging manufacturing process

    DOEpatents

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

    2002-01-01

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

  5. Effects of processing parameters in P/M steel forging on part properties: A review part I powder preparation, compaction, and sintering

    NASA Astrophysics Data System (ADS)

    Duggirala, R.; Shivpuri, R.

    1992-08-01

    In the last decade, powder metallurgy (P/M) technology has made marked advances in competitive manufacturing. P/M offers design opportunities that are not possible with other methods, as well as significant cost savings. In the automotive industry, P/M forgings are being developed for applications requiring good high- cycle fatigue properties. The processing parameters, material characteristics, individual stages of compaction and parts production, deformation and densification mechanics and tooling, and preform design influence the properties of the P/M part and related economics. Therefore, a review of the various parameters involved in the different stages of P/M steel forging in net-shape manufacturing and their implications on resulting properties of the P/M parts is presented in a three part review. Key parameters in steel powder preparation, compaction, and sintering of P/M forging and their effect on part properties are described in Part I. Part II discusses issues of forging the sintered compact, and Part III reviews currently available analysis methods for studying the powder forging process.

  6. Deformation processes in forging ceramics

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  7. Design of forging process variables under uncertainties

    NASA Astrophysics Data System (ADS)

    Repalle, Jalaja; Grandhi, Ramana V.

    2005-02-01

    Forging is a complex nonlinear process that is vulnerable to various manufacturing anomalies, such as variations in billet geometry, billet/die temperatures, material properties, and workpiece and forging equipment positional errors. A combination of these uncertainties could induce heavy manufacturing losses through premature die failure, final part geometric distortion, and reduced productivity. Identifying, quantifying, and controlling the uncertainties will reduce variability risk in a manufacturing environment, which will minimize the overall production cost. In this article, various uncertainties that affect the forging process are identified, and their cumulative effect on the forging tool life is evaluated. Because the forging process simulation is time-consuming, a response surface model is used to reduce computation time by establishing a relationship between the process performance and the critical process variables. A robust design methodology is developed by incorporating reliability-based optimization techniques to obtain sound forging components. A case study of an automotive-component forging-process design is presented to demonstrate the applicability of the method.

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

    NASA Astrophysics Data System (ADS)

    Zhang, Pu; Yao, Zhenqiang; Du, Zhengchun

    2013-07-01

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

  9. FEM simulation of hot forging process to predict microstructure evolution

    NASA Astrophysics Data System (ADS)

    Zhang, Shi-Hong; Zhang, Hai-Yan; Song, Hong-Wu; Cheng, Ming

    2013-05-01

    Two phase titanium alloy-TC11 alloy and Superalloy-IN718 alloy are being considered for high-temperature structural applications in aero-engine because of their excellent mechanical properties at elevated temperatures. The mechanical properties of their forgings are sensitive to the microstructure. Therefore, it is crucial to obtain a corresponding microstructure by controlling the hot working process. For the forging of TC11 alloy, the ingot break down in the subtransus region is an important process which acted as the primary role in the transformation of lamellar structure to equiaxed one as well as its poor formability because of lower deformation temperature. In this paper, the lamellar globularization kinetics and fracture behavior during forging are studied and modeled. For the hot forging of IN718 alloy. the grain size evolution is an important process. As the ? phase in the alloy can control grain growth through the strong pinning effect, the effect of ? phase on the microstructure evolution during hot working has been considered in this paper, and the microstructure evolution model has been established. As a applications, The lamellar globularization and fracture during the subtransus cogging process of large size TC11 alloy billet, and the microstructure development during the hot forging process of IN718 alloy turbine disk have been investigated commercial FE Software with user subroutines. The prediction results showed good agreement with the actual ones.

  10. Process modelings and simulations of heavy castings and forgings

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2004-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  13. 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.

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

    SciTech Connect

    Pepelnjak, Tomaz; Kuzman, Karl; Kokol, Anton

    2011-05-04

    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.

  15. Forging Advisor

    SciTech Connect

    Kerry Barnett

    2003-03-01

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

  16. Mesoscale simulation of microstructure evolution during multi-stage hot forging processes

    NASA Astrophysics Data System (ADS)

    Chen, Fei; Cui, Zhenshan

    2012-06-01

    The paper presents a two-dimensional cellular automaton (CA) approach coupled with a topology deformation technique for quantitative and topographic prediction of the microstructure evolution during multi-stage hot forging processes. The simulation presented in this work was implemented by an in-house developed C++ program. The grain topography, recrystallization fraction and average grain size were also obtained during a four-hit forging process. The simulated results agree well with the experimental data in terms of average grain size, suggesting that the developed CA model is a reliable numerical approach for predicting microstructure evolution for ultra-super-critical rotor steel during multi-stage hot forging processes.

  17. Prediction of Final Material State in Multi-Stage Forging Processes

    NASA Astrophysics Data System (ADS)

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

    2004-06-01

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

  18. Proposal to study stem forgings

    SciTech Connect

    Odegard, B.C.

    1982-06-25

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

  19. Modeling microstructure evolution in the delta process forging of superalloy IN718 turbine discs

    NASA Astrophysics Data System (ADS)

    Zhang, Haiyan; Zhang, Shihong; Cheng, Ming; Zhao, Zhong

    2013-05-01

    The microstructure development in the Delta Process (DP) forging of Superalloy IN718 turbine discs were predicted using the combined approach of axisymmetric finite element simulation and modeling for the dynamic recrystallization and grain growth. In order to establish the deformation constitutive equation and dynamic recrystallization models for the DP process of Superalloy IN718, the isothermal compression tests were carried out in the temperature range 950 to 1010 °C and strain rates range 0.001 to0.1s-1. Moreover, the isothermal heat treatment tests after hot deformation were conducted in the temperature range 950 to 1040°C to generate the grain growth model. The experimental results indicated the existence of the ? phase could make the activation energy of deformation increase. Furthermore, the existence of the ? phase could stimulate the occurrence of dynamic recrystallization, and the grain growth was restrained due to the pinning effect of ? phase. The predicted grain size and its distribution in the DP forging of Superalloy IN718 turbine discs were compared with the actual microstructures deformed by the hot die forging. It was found that the forging with uniform fine grains could be obtained by the application of DP process to the forging of the turbine disk, in which the alloy was pre-precipitated ? phase after the baiting in the original process.

  20. 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.

  1. Powder forging

    SciTech Connect

    Kuhn, H.A.; Ferguson, B.L.

    1990-01-01

    Fundamental and applications aspects of powder-forging (PF) technology are examined in an introduction and reference guide for practicing engineers. The treatment is based on a combined metallurgical-mechanical approach, and the potential benefits of FEM process simulations and expert-system design-optimization methods are illustrated. Chapters are devoted to materials considerations for PF, PF mechanics, PF analysis, PF process design, and PF practice. Extensive diagrams, drawings, graphs, photographs, and micrographs are provided. 160 refs.

  2. Manufacturing of Precision Forgings by Radial Forging

    SciTech Connect

    Wallner, S.; Harrer, O.; Buchmayr, B.; Hofer, F.

    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.

  3. Manufacturing of Precision Forgings by Radial Forging

    NASA Astrophysics Data System (ADS)

    Wallner, S.; Harrer, O.; Buchmayr, B.; Hofer, F.

    2011-01-01

    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.

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

    SciTech Connect

    Filice, Luigino; Gagliardi, Francesco; Umbrello, Domenico; Shivpuri, Rajiv

    2007-05-17

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

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

    NASA Astrophysics Data System (ADS)

    Filice, Luigino; Gagliardi, Francesco; Shivpuri, Rajiv; Umbrello, Domenico

    2007-05-01

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

  6. Forming limit prediction of powder forging process by the energy-based elastoplastic damage model

    NASA Astrophysics Data System (ADS)

    Yeh, Hung-Yang; Cheng, Jung-Ho; Huang, Cheng-Chao

    2004-06-01

    An energy-based elastoplastic damage model is developed and then applied to predict the deformation and fracture initiation in powder forging processes. The fracture mechanism is investigated by the newly proposed damage model, which is based on the plastic energy dissipation. The developed formulations are implemented into finite element program ABAQUS in order to simulate the complex loading conditions. The forming limits of sintered porous metals under various operational conditions are explored by comparing the relevant experiments with the finite element analyses. The sintered iron-powder preforms of various initial relative densities (RDs) and aspect ratios are compressed until crack initiates. The deformation level of the bulged billets at fracture stroke obtained from compressive fracture tests is utilized to validate the finite element model and then the forming limit diagrams are constructed with the validated model. This model is further verified by the gear blank forging. The fracture site and corresponding deformation level are predicted by the finite element simulations. Meanwhile, the gear forging experiment is performed on the sintered preforms. The predicted results agree well with the experimental observations.

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

    NASA Astrophysics Data System (ADS)

    Ohnishi, Masayuki; Yamaguchi, Mitsugi; Ohashi, Osamu

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

  8. Steel forgings

    SciTech Connect

    Nisbett, E.G.; Melilli, A.S.

    1986-01-01

    This book contains over 30 papers. Some of the titles are: Integrity of Full-Integral, Low-Pressure Nuclear Turbine Forgings; Seamless Shell Course Forgings for Heavy-Wall Reactor Vessels: A Forgemasters Critical Review; Application of New Types of Ingots to the Manufacturing of Heavy Pressure Vessel Forgings; Manufacturing of Large and Integral-Type Steel Forgings for Nuclear Steam Supply Components; and Advanced Technology of Heavy-Section Tube Sheets for Nuclear Power Generation.

  9. Correcting the Stress-Strain Curve in the Stroke-Rate Controlling Forging Process

    NASA Astrophysics Data System (ADS)

    Li, Y. P.; Matsumoto, H.; Chiba, A.

    2009-05-01

    In this article, a detailed description of the friction correction, adiabatic correction, and the correction from the stroke-rate controlling process into the strain-rate controlling process on the IHS38MSV hypoeutectoid steel is provided. By using compensated data, processing maps were plotted and used to predict the optimum hot forging process. The compressive tests were performed at stroke rates ranging from 0.12 to 120 mm/s and temperatures ranging from 800 °C to 1200 °C by using ThermecMaster-Z equipment. The results showed that the correction by instant friction coefficient, which was carried out on the basis of previous research, could be extended to wider experimental conditions. The corrected data from both stroke-rate controlling and strain-rate controlling processes were in good agreement with each other, indicating that the present correction from the stroke rate into the strain-rate correction is practical and appropriate.

  10. 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

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

    SciTech Connect

    Pletka, B.J.; Subhash, G.; Edelman, D.; Dowding, R.J.

    1996-06-01

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

  12. 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.

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

    NASA Astrophysics Data System (ADS)

    Ducato, Antonino; Fratini, Livan; Micari, Fabrizio

    2013-05-01

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

  14. The evaluation of Ontario Forge Company as a qualified forging vendor

    SciTech Connect

    West, A.J.; Odegard, B.C.

    1981-10-12

    There has been a long standing need to develop a second source of WR quality forgings for the manufacturing of J-line hardware at RF. With this objective, Ontario Forge Company was recently evaluated to determine if their equipment and skills were compatible with the forging requirements. The results of this evaluation were compared to test results on WR forgings of a similar design produced by Precision Forge Company. The Ontario Forge Company forgings exhibited mechanical properties, grain flow and microstructures equivalent to those of Precision Forge Company. The Ontario Forge Company performance on this contract justifies the qualification of their process for producing non-critical reservoir forgings. Qualifying Ontario Forge Company for critical reservoir forgings is recommended only after sufficient production experience and storage data is acquired.

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

    ERIC Educational Resources Information Center

    Dade County Public Schools, Miami, FL.

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

  16. Influences of sinter-forging parameters and texture on the critical transport current density of Bi-Pb-Sr-Ca-Cu-O (2223) superconductors

    NASA Astrophysics Data System (ADS)

    Caillard, R.; Gomina, M.

    2001-09-01

    It is well established that the critical temperature and current density of bulk 2223 superconductors are drastically limited by the presence of low-TC phases, misalignment of the grains and weak intergranular junctions in the (a,b) planes. Herein, an optimization of the sinter-forging process of the Bi-Pb-Sr-Ca-Cu-O (2223) superconducting ceramic, synthesized by a rapid sol-gel method, has been performed. The kinetics of formation of the Bi-2223 phase, which are strongly dependent on the calcination and sintering conditions, were optimized with a goal to raise the purity of the material up to 95% Bi-2223. The precursor powder was pressed at 1.5 t cm-2, placed under uniaxial stress up to 46.8 MPa and then heated, between 830 and 850 °C, remaining below the melting temperature. This process resulted in large, well textured samples displaying disorientation of less than 4.8° with respect to the (a,b) plane for 50% of the grains. The sinter-forging parameters (temperature, stress and time under load) and the resulting texture of the samples were correlated with the critical transport current density, Jc, at 77 K, and self-field. Maximum Jc values up to 8000 A cm-2 and critical temperatures, TC of 108 K were achieved through an optimization of the stress and the heat treatment schedules. The results indicate that annealing under a 7.5% O2/92.5% N2 atmosphere leads to higher Jc values.

  17. 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).

  18. Total quality management of forged products through finite element simulation

    NASA Astrophysics Data System (ADS)

    Chandra, U.; Rachakonda, S.; Chandrasekharan, S.

    The paper reviews the entire thermo-mechanical history experienced by a complex shaped, high strength forged part during all stages of its manufacturing process, i.e. forging, heat treatment, and machining. It examines the current practice of selecting the process parameters using finite element simulation of forging and quenching operations on an individual basis. Some recent work related to the simulation of aging and machining operations is summarized. The capabilities of several well-known finite element codes for these individual simulations are compared. Then, an integrated simulation approach is presented which will permit the optimization of process parameters for all operations, as opposed to a single operation. This approach will ensure a total quality management of forged products by avoiding costly problems which, under the current practice, are detected only at the end of the manufacturing cycle, i.e. after final machining.

  19. Measurement system for hot heavy forgings and its calibration

    NASA Astrophysics Data System (ADS)

    Du, Yueyang; Du, Zhengchun

    2011-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  1. 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

  2. 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

  3. Saugus Iron Works Forge

    USGS Multimedia Gallery

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

  4. New Trends in Forging Technologies

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  5. 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.

  6. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  8. 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.

  9. 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.

  10. 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.

  11. Development of powder-forged connecting rods

    SciTech Connect

    Imahashi, K.; Tsumuki, C.; Nagare, I.

    1984-01-01

    In comparison with conventional hot forging process, powder forging process has much advantage such as good dimensional accuracy, minimum scattering of weight, etc. In spite of much advantage, the powder forged parts have not been mass-produced except for relatively simple shape parts because of technical and economic problems such as low productivity. Solving these problems, powder forging process was applied to connecting rods which required fatigue strength and minimum scattering of weight, and which were complex in shape. As a result, for the first time in the world, mass-production of powder forged connecting rods was carried out, and its properties are as follows: (1) Sufficient fatigue strength; (2) Minimum scattering of weight; and (3) Good dimensional accuracy.

  12. Numerical Simulation on the Die Filling Process of the Thixo-Forging of Al-7 wt pct Si/Al-22 wt pct Si Bimetal Composite

    NASA Astrophysics Data System (ADS)

    Wang, Guangxu; Huang, Honghua; Yang, Zhao; Shi, Xiaocheng; He, Xiaolong

    2015-10-01

    A bimetal semi-solid fluid has more complicated flow behaviors than a normal semi-solid fluid during thixo-forging. In order to clarify the detailed properties of the bimetal thixo-forging, the effects of billet temperatures and frictions on flow behaviors of the Al-7 wt pct Si/Al-22 wt pct Si bimetal thixo-forging were investigated by commercial software DEFORM-3D. The simulation results show that shear force was unable to be transferred from the upper billet on the drop die side to the bottom billet on the counter die side efficiently in the initial stage of die filling. Only when the upper billet severely deformed, did the shear force deform the bottom billet. A stiffer upper billet can enhance the efficiency of shear force transfer. The processing temperature, the relative stiffness between the upper billet and bottom billet, and frictions between dies and billets, as well as friction between billets, were important factors to control the interface outline of the bimetal parts. The experimental results are consistent with the simulation results.

  13. Controlled Forging of a Nb Containing Microalloyed Steel for Automotive Applications

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  14. Superplastic forging nitride ceramics

    DOEpatents

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

    1988-03-22

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

  15. Enhancement of Aluminum Alloy Forgings through Rapid Billet Heating

    SciTech Connect

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

    2006-06-01

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

  16. Mechanical Testing Development for Reservoir Forgings

    SciTech Connect

    Wenski, E.G.

    2000-05-22

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

  17. Near-Net Forging Technology Demonstration Program

    NASA Technical Reports Server (NTRS)

    Hall, I. Keith

    1996-01-01

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

  18. Grain evolution during hot forging

    NASA Astrophysics Data System (ADS)

    Jin, Quanlin

    2013-05-01

    A review on grain evolution during hot forging is presented in this paper. The discussion focus is on the experimental law, the microscopic mechanism, the physical model and the evolution equations of grain refinement and growth. This is because the grain evolution is the most important microstructure evolution effecting on the part mechanical behaviors, and to establish reasonable grain evolution is a very important and difficult work for macro microscopic coupling constitutive equation. The following contents about constitutive equation and grain evolution are discussed. 1) The experimental phenomena and evolution laws of grain growth and grain refinement under differential working conditions (deformation, heating, cooling) in order to adapt to the needs of numerical simulation of whole forging process. 2) The advantages and disadvantages of the traditional empirical equations on grain growth, grain refinement and recrystallization process are analyzed. 3) The recent advances in physic models for dynamic recrystallizaton and dynamic grain growth are introduced in detail. Comparing to the empirical equations, these models are closer to the actual physical process. The models not only describe the details of grain changes, but also reveal the relationship between the accumulated dislocations energy and grain size evolution. In addition, the assumptions used in the models and their influences on prediction function are also discussed in order to improve the models.

  19. The thermal modeling of large axisymmetric forgings

    NASA Astrophysics Data System (ADS)

    van Tyne, C. J.; Focht, R. B.; Nelson, T. D.; Reese, W.

    1994-09-01

    Three thermal models for simulating the heating cycles used for large forgings were developed. They were designed for accuracy, user friendliness, and rapid calculation on a personal computer. The results that are obtained from these models are the temperature profiles that occur within the ingot, forging or roll at various depths from the surface. The values for these temperature versus time curves can be used to examine several features about the heat treatment process. The example presented in this paper showed the effect of heating rate and hold at 704 °C on the surface-to-center temperature difference that occurs in a medium carbon steel ingot.

  20. 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

    2015-09-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Fouilland, Laurence; Mansori, Mohamed El

    2011-01-01

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

  2. Secondary development of finite element simulation program and experimental verification of multi-step continuous forging

    NASA Astrophysics Data System (ADS)

    Xia, Qinxiang; Xiang, Ke; Zhu, Ningyuan; Song, Asheng

    2013-05-01

    For long-shaft heavy forgings, multiple forging passes and several blows per pass are involved, the forging billet is fed at a certain distance after per blow and is rotated a certain angle after per pass, so the forging process is very time-consuming. The numerical simulation has become one kind of the most effective methods to study the forming process of heavy forgings. Presently, the simulation of the forging process of heavy forgings is mainly based on the multi-step simple forming process modeling, the influences between each pass are usually ignored. The function call module in text mode based on DEOFRM-3D software was developed to realize the simulation of multi-step continuous forming process of heavy forgings, therefore, the numerical simulation model is in line with reality. The whole multi-step continuous forging process was simulated based on the developed finite element simulation program, the surface temperature and dimension variation of forgings were obtained, and the corresponding experiments were carried out. It shows that the simulation results conform well to the experimental one. It indicates that the developed finite element simulation program can be used to simulate the multi-step continuous forging effectively.

  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. Modeling and simulation of austenite grain evolution for heavy forging steel 30Cr2Ni4MoV undergoing hot deformation

    NASA Astrophysics Data System (ADS)

    Cui, Zhenshan; Li, Cuidong; Chen, Fei; Sui, Dashan

    2013-05-01

    30Cr2Ni4MoV is widely used as heavy forging materials for low pressure rotors which equips the ultra-supercritical power generations. The final properties of the heavy forging products relies apparently on the grain size of the material, so that the grain should be refined and homogenized during forming process through controlling the working parameters during forming process. For this purpose, the research on the modeling and simulation of austenite grain evolution is conducted for different forming stages: the grain growth during heating, dynamic recrystallization (DRX) during hitting, and meta-dynamic (MDRX) and static recrystallization (SRX) during hitting intervals. Experiment-based phenomenological models, as easy ways to characterize the grain evolution, are established for the process of heating and single-hit, while the Cellular Automaton simulations are applied for tracing more complex recrystallization process during multi-hit deformations. The research shows that, for heavy forgings, the long-time heating process can cause very coarse grains which are harmful to the final properties. Therefore, in order to refine and homogenize the grain size for the heavy forgings, the working parameters for forging should be determined to ensure the recrystallization can be completed and the deformation can be uniformly distributed. Some applications of the models and simulation method in multi-hit process are also demonstrated.

  5. Superplastic forging nitride ceramics

    DOEpatents

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

    1988-03-22

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

  6. Surveillance of industrial processes with correlated parameters

    DOEpatents

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

    1996-01-01

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

  7. Surveillance of industrial processes with correlated parameters

    DOEpatents

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

    1996-12-17

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

  8. Facilitation Guide Forging the Link

    E-print Network

    Facilitation Guide Forging the Link: Linking the Economic Incentives of Low Impact Development or Low Impact Development for our communities. You have heard just a bit of information describing some heard? What about inconsistent? #12;Forging the Link: Linking the Economic Benefits of Low Impact

  9. Visual parameter optimisation for biomedical image processing

    PubMed Central

    2015-01-01

    Background Biomedical image processing methods require users to optimise input parameters to ensure high-quality output. This presents two challenges. First, it is difficult to optimise multiple input parameters for multiple input images. Second, it is difficult to achieve an understanding of underlying algorithms, in particular, relationships between input and output. Results We present a visualisation method that transforms users' ability to understand algorithm behaviour by integrating input and output, and by supporting exploration of their relationships. We discuss its application to a colour deconvolution technique for stained histology images and show how it enabled a domain expert to identify suitable parameter values for the deconvolution of two types of images, and metrics to quantify deconvolution performance. It also enabled a breakthrough in understanding by invalidating an underlying assumption about the algorithm. Conclusions The visualisation method presented here provides analysis capability for multiple inputs and outputs in biomedical image processing that is not supported by previous analysis software. The analysis supported by our method is not feasible with conventional trial-and-error approaches. PMID:26329538

  10. Effects of process parameters on hydrothermal carbonization

    NASA Astrophysics Data System (ADS)

    Uddin, Md. Helal

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

  11. Sinter-forging of strongly textured Bi2223 discs with large Jcs: nucleation and growth of Bi2223 from Bi2212 crystallites

    NASA Astrophysics Data System (ADS)

    Guilmeau, E.; Chateigner, D.; Noudem, J. G.

    2002-10-01

    Dense Bi2223 superconductor discs with a highly oriented structure were prepared by the sinter-forging method. A detailed investigation of the processing parameters has been carried out on the phase assemblage, the particle size of the calcined precursor powder and the sinter-forging time and temperature. A high transport critical current density, Jc, was obtained from a starting powder rich in Bi2212 and secondary phases. Using fine powder, a high degree of orientation, larger than those of multifilamentary tapes, and excellent intergrain connection were observed. The optimal sinter-forging temperature was found to be in the range of 845-850 °C and the transport critical current densities reached values of 12 700 A cm-2 at 77 K in self-field. The combination of textural and microstructural investigations testify that a nucleation-growth mechanism from the Bi2212 particles is responsible for the Bi2223 phase formation, rather than an intercalation process.

  12. 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.

  13. Prediction of Microstructure in High-Strength Ductile Forging Parts

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

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

    SciTech Connect

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

    2007-05-17

    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.

  15. 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.

  16. Inference and parameter estimation for diffusion processes 

    E-print Network

    Lyons, Simon

    2015-06-29

    Diffusion processes provide a natural way of modelling a variety of physical and economic phenomena. It is often the case that one is unable to observe a diffusion process directly, and must instead rely on noisy ...

  17. FORGING THE LINK Linking the Economic Benefits

    E-print Network

    FORGING THE LINK Linking the Economic Benefits of Low Impact Development and Community Decisions FORGING THE LINK Linking the Economic Benefits of Low Impact Development and Community Decisions A Study #12;FORGING THE LINK Linking the Economic Benefits of Low Impact Development and Community Decisions

  18. Saugus Iron Works Forge and Mill

    USGS Multimedia Gallery

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

  19. A New Method for Controlling Billet Temperature During Isothermal Die Forging of a Complex Superalloy Casing

    NASA Astrophysics Data System (ADS)

    Lin, Y. C.; Wu, Xian-Yang

    2015-09-01

    Isothermal die forging is one of near net-shape metal-forming technologies. Strict control of billet temperature during isothermal die forging is a guarantee for the excellent properties of final product. In this study, a new method is proposed to accurately control the billet temperature of complex superalloy casing, based on the finite element simulation and response surface methodology (RSM). The proposed method is accomplished by the following two steps. Firstly, the thermal compensation process is designed and optimized to overcome the inevitable heat loss of dies during hot forging. i.e., the layout and opening time of heaters assembled on die sleeves are optimized. Then, the effects of forging speed (the pressing velocity of hydraulic machine) and its changing time on the maximum billet temperature are discussed. Furthermore, the optimized forging speed and its changing time are obtained by RSM. Comparisons between the optimized and conventional die forging processes indicate that the proposed method can effectively control the billet temperature within the optimal forming temperature range. So, the optimized die forging processes can guarantee the high volume fraction of dynamic recrystallization, and restrict the rapid growth of grains in the forged superalloy casing.

  20. 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)

  1. 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.

  2. Simulation of Deformation Texture Evolution During Multi Axial Forging of Interstitial Free Steel

    NASA Astrophysics Data System (ADS)

    Gurao, N. P.; Kumar, P.; Sarkar, A.; Brokmeier, H.-G.; Suwas, Satyam

    2013-04-01

    Bulk texture measurement of multi-axial forged body center cubic interstitial free steel performed in this study using x-ray and neutron diffraction indicated the presence of a strong {101}<111> single texture component. Viscoplastic self-consistent simulations could successfully predict the formation of this texture component by incorporating the complicated strain path followed during this process and assuming the activity of {101}<111> slip system. In addition, a first-order estimate of mechanical properties in terms of highly anisotropic yield locus and Lankford parameter was also obtained from the simulations.

  3. Determination Of Slitting Criterion Parameter During The Multi Slit Rolling Process

    NASA Astrophysics Data System (ADS)

    Stefanik, Andrzej; Mróz, Sebastian; Szota, Piotr; Dyja, Henryk

    2007-05-01

    The rolling of rods with slitting of the strip calls for the use of special mathematical models that would allow for the separating of metal. A theoretical analysis of the effect of the gap of slitting rollers on the process of band slitting during the rolling of 20 mm and 16 mm-diameter ribbed rods rolled according to the two-strand technology was carried out within this study. For the numerical modeling of strip slitting the Forge3® computer program was applied. The strip slitting in the simulation is implemented by the algorithm of removing elements in which the critical value of the normalized Cockroft - Latham criterion has been exceeded. To determine the value of the criterion the inverse method was applied. Distance between a point, where crack begins, and point of contact metal with the slitting rollers was the parameter for analysis. Power and rolling torque during slit rolling were presented. Distribution and change of the stress in strand while slitting were presented.

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

    SciTech Connect

    Switzner, Nathan; Neidt, Ted; Hollenbeck, John; Knutson, J.; Everhart, Wes; Hanlin, R.; Bergen, R.; Balch, D. K.

    2012-09-06

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

  5. Improved Thermoelectric Performance of p-Type Bismuth Antimony Telluride Bulk Alloys Prepared by Hot Forging

    NASA Astrophysics Data System (ADS)

    Shen, J. J.; Yin, Z. Z.; Yang, S. H.; Yu, C.; Zhu, T. J.; Zhao, X. B.

    2011-05-01

    The thermoelectric (TE) performance of Bi0.5Sb1.5Te3 polycrystalline alloys has been improved by a simple hot-forging process. No obvious texture was observed in the x-ray diffraction (XRD) patterns of the hot-forged samples. Transport property measurements indicated that the hot-forged samples possessed extremely low thermal conductivities. A maximum ZT value of ˜1.1 at room temperature was obtained for the sample forged under 30 MPa pressure, being almost 50% more than that of the initial unforged alloy. High-resolution transmission electron microscopy (HRTEM) observations suggested that the high density of lattice defects of the hot-forged samples could be responsible for the extremely low thermal conductivities.

  6. 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.

  7. Implementation of state-of-the-art rotor forging evaluation to manage the oldest rotor fleet in the USA

    SciTech Connect

    Puri, A.; Steakley, M.; McCann, D.

    1995-12-31

    The average age of the Tennessee Valley Authority`s (TVA) fossil fleet is almost 40 years with a large population of ``C`` grade rotors manufactured in the 1950`s. Until 1991, TVA relied upon the OEM`s to support the rotor forging assessment and establish the reinspection intervals. Based on the OEM`s recommendations most turbine/generator overhauls were governed by the forging reinspection interval. In the spring of 1992, TVA initiated an engineered forging evaluation process that involved state-of-the-art amplitude independent, target-motion based Ultrasonic And Data Processing System (UDRPS) forging inspection, forging material sampling, and fracture mechanics analysis. This paper outlines TVA`s state-of-art rotor forging evaluation program, results achieved since its introduction and the long range benefits to TVA.

  8. Sinter-forging of nanophase TiO sub 2

    SciTech Connect

    Uchic, M.; Hofler, H.J.; Flick, W.J.; Tao, R.; Averback, R.S. . Dept. of Materials Science and Engineering); Kurath, P. . Dept. of Mechanical Engineering)

    1992-03-01

    Considerable effort has been directed in recent years to developing ceramic materials that can be both sintered to full density at low temperatures and processed by superplastic forming. One strategy for achieving this goal has been to reduce the particle size of the starting powder, and by anaphase processing, particles of sizes less than {approx}10 nm can now be realized. Indeed, recent studies on nanophase ceramics have demonstrated that sintering temperatures can be reduced dramatically and that nanophase ceramics have excellent potential for superplastic forming. Nevertheless, the grain growth that occurs during the processing of these new materials restricts their applicability. In nanophase (n-) TiO{sub 2}, some progress in controlling grain size has been achieved by using dopants or hot pressing. Sinter-forging offers another means to achieve this goal, although this method has been applied mostly to materials with larger grains. Studies of sinter-forging are also useful for elucidating the mechanisms of sintering and creep in ceramic materials. In the present paper, the authors examine the characteristics of sinter-forging in n-TiO{sub 2}. Only limited studies of sinter-forging have thus far been performed on well characterized powders of comparable size, and even these had a somewhat larger grain size.

  9. Laser-dispersing of forging tools using AlN-ceramics

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  10. 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.

  11. T3PS: Tool for Parallel Processing in Parameter Scans

    E-print Network

    Vinzenz Maurer

    2015-02-27

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

  12. T3PS: Tool for Parallel Processing in Parameter Scans

    E-print Network

    Maurer, Vinzenz

    2015-01-01

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

  13. Hot forging of melt quenched powder: Microstructure development and kinetics of densification

    NASA Astrophysics Data System (ADS)

    Keshavan, Hrishikesh

    Hot powder forging is a new process for making scalable and cost-effective nanocrystalline ceramics. It utilizes powder typically between 5 mum to 25 mum to nucleate very stable crystallite sizes well below 100 nm. These particles superplastically deform at relatively moderate temperature and stress. Hence, rapid densification at high creep rates is achieved with limited grain growth. A novel way to achieve high creep rate is to take advantage of partially amorphous powders that are obtained by one of the many available rapid quenching processes. Our study uses a plasma flame to melt the spray-dried aggregates of a particular composition and rapidly quench into water that results in metastable, optically transparent powder. The plasma sprayed powder is first hot pressed to obtain cylindrical pellets and then hot-forged at various stresses and temperatures to obtain optimum creep rates. Eutectic oxide compositions were studied due to their low melting point and better glass forming ability in an effort to optimize both the composition and processing parameters. Five binary compositions of alumina, zirconia and magnesium aluminate spinel and the effect of adding borosilicate glass on creep rates and microstructure were investigated. Their phase evolution and crystallite growth were examined in a detailed annealing study. The final densities after hot forging were composition dependent and ranged from 86% to 100% at 1350°C. Creep rates of the binary eutectic increased by an order of magnitude when alumina was substituted with spinel or when borosilicate glass was added. The highest creep rate obtained would correspond to 10-4 1/s for 40 MPa at 1350°C. SEM studies confirm that the densification is by plastic deformation of particles. TEM studies reveal nano-sized zirconia either in an alumina or spinel matrix. The grain morphology was cellular in compositions without glass and acicular in compositions with glass.

  14. A study on microstructures and properties of P/M valve seats of hot forging by laser irradiation

    NASA Astrophysics Data System (ADS)

    Liu, Shuangyu; Hu, Jiandong; Wang, Hongying; Guo, Zuoxing; Yu, Cai; Chumakov, A. N.; Bosak, A.

    2007-06-01

    A CO 2 laser was used as heating source for hot forging. Powder/metallurgy (P/M) valve seats for car engine was studied by this novel process. The effects of compression ratio and tempering temperature followed by laser irradiation on the microstructures and mechanical properties were investigated. It was indicated that the amount of the recrystallized grains increased with increasing compression ratio, especially when the compression ratio was above a certain value (18.70%), resulting in more refined grains. Good properties including density, radial crushing strength and hardness can be obtained by optimizing processing parameters.

  15. 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.

  16. Reactor pressure vessel with forged nozzles

    DOEpatents

    Desai, Dilip R. (Fremont, CA)

    1993-01-01

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

  17. LOW COMPLEXITY MODELLING AND PARAMETER ESTIMATION IN COPPER BIOLEACHING PROCESSES

    E-print Network

    Braslavsky, Julio H.

    LOW COMPLEXITY MODELLING AND PARAMETER ESTIMATION IN COPPER BIOLEACHING PROCESSES Boris I. Godoy of copper ores, naturally occurring bacteria often act as a catalytic agent in the process, signifi- cantly enhancing the conversion of metal compounds into their water soluble forms. In such cases, we refer

  18. A novel edge detection approach used for online dimensional measurement of heavy forging

    NASA Astrophysics Data System (ADS)

    Hu, Chunhai; Liu, Bin; Song, Xiaoxue

    2008-12-01

    An edge detection method was developed with capability of objectively detecting significant edges in images of high temperature forging. The issue of potential image degradation when viewing hot objects was serious concerned. The paper was absorbed in online dimensional measurement using stereovision technology. Particular characteristics of high temperature forging were described. A global self-adaptive thresholding preprocessing was used for eliminating most redundant mill scale regions and segmenting object from complex background. Then, the feature edges was detected and localized at single pixel scale. Post processing of surround suppression as final additional step was applied to improve edges detection performance by extracting genuine feature edges from edges map. The entire method was performed on a real hot forging image and the performance had been proved in experiment result. The approach was specifically designed for using in online dimensional measurement of heavy forging, but generally enough to be applied to other edge detection of any high-temperature object.

  19. 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

  20. Stellar atmospheric parameter estimation using Gaussian process regression

    NASA Astrophysics Data System (ADS)

    Bu, Yude; Pan, Jingchang

    2015-02-01

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

  1. Photogrammetry based system for the measurement of cylindrical forgings axis straightness

    NASA Astrophysics Data System (ADS)

    Zato?ilová, Aneta; Poliš?uk, Radek; Paloušek, David; Brandejs, Jan

    2013-04-01

    Dimension measurement of hot large forgings is necessary for manufacturing process and quality control. Conventional non-contact optical measurement methods are not applicable, mainly because of high temperature and large dimensions. A novel approach to the axis staightness measurement of the cylindrical forging, based on the principle of photogrammetry and edge detection, is described in this paper. Proposed system is developing under laboratory conditions, but the actual conditions of steel production are also considered. Demands on the measurement system were set by our industrial partner, producer of cylindrical forgings with length of 4 to 20 m and diameter up to 1.4 m. The system should be able to detect axis straightness deviations higher than 5 mm (system accuracy has to be better than 5 mm). Cylindrical forgings are 4 to 20 m long with diameter up to 1.4 m. The approach is based on the assumption that the actual shape of the cylindrical forging axis can be determined (in the simplest case) using four boundary curves which lie in two mutually perpendicular planes. Four boundary curves can be obtained by detecting the forgings edges in two images. The article provides results of first validation of proposed method in laboratory conditions. Measurement repeatability was validated by carrying out ten measurements of a deformed rod. Each measurement was compared with a measurement performed by industrial fringe projection scanner Atos III Triple Scan in order to verify the accuracy of the proposed method.

  2. 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

  3. Compressed Air System Optimization Project Improves Production at a Metal Forging Plant (Modern Forge, TN, Plant)

    SciTech Connect

    2000-12-01

    In 1995, Modern Forge of Tennessee implemented a compressed air system improvement project at its Piney Flats, Tennessee, forging plant. Due to the project’s implementation, the plant was able to operate with fewer compressors and improve its product quality, thus allowing it to increase productivity. The project also resulted in considerable energy and maintenance savings.

  4. Development of Iron-based Closed-Cell Foams by Powder Forging and Rolling

    NASA Astrophysics Data System (ADS)

    Paswan, Dayanand; Mistry, Dhananjay; Sahoo, K. L.; Srivastava, V. C.

    2013-08-01

    In the present investigation, an attempt has been made to develop in situ sandwich Fe-based foams using powder forging and rolling. Several metal carbonates are first studied by thermo gravimetric analysis to find out their suitability to be used as foaming agent for iron-based foams. Barium carbonate is found to be the most promising foaming agent among other suitable options studied such as SrCO3, CaCO3, MgCO3, etc. The effects of process parameters such as precursor composition, sintering temperature, foaming temperature and time, and content of foaming agent have been studied. The microstructural characteristics of the sintered precursor have been studied by means of optical and scanning electron microscopy. It was found that a good pore structure can be obtained using 2-3% C in Fe and 3% BaCO3 as foaming agent and by foaming at around 1350 °C for 3-6 min.

  5. Design for manufacturability: Design for forging, part 2

    NASA Astrophysics Data System (ADS)

    Rigioni, A.; Boothroyd, G.

    1981-04-01

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

  6. 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.

  7. Optimisation of processing parameters in laser sintering of metallic powders

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

    Optimisation of laser sintering of submicron metal powders has been studied in connection with unsteady heat transfer in a porous powder layer under conditions of rapid phase transformations. The heating rate, cooling rate and depth of the sintered layer are estimated after analysis of geometrical characteristics of the metallic powder. The computer simulation revealed that the control parameters of the process are the scanning velocity and effective optical penetration depth. The last parameter depends on porosity and morphology of the powder layer. The effects of the laser annealing power, frequency of laser pulses and beam radius have a smaller effect on the depth of the sintering layer. At porosities higher than 70%, the mechanism of heat transfer drastically changes and the approximation of continuum used frequently in analytical models for draft estimations becomes incorrect.

  8. Improving gravitational-wave parameter estimation using Gaussian process regression

    E-print Network

    Moore, Christopher J; Chua, Alvin J K; Gair, Jonathan R

    2015-01-01

    Folding uncertainty in theoretical models into Bayesian parameter estimation is necessary in order to make reliable inferences. A general means of achieving this is by marginalising over model uncertainty using a prior distribution constructed using Gaussian process regression (GPR). Here, we apply this technique to (simulated) gravitational-wave signals from binary black holes that could be observed using advanced-era gravitational-wave detectors. Unless properly accounted for, uncertainty in the gravitational-wave templates could be the dominant source of error in studies of these systems. We explain our approach in detail and provide proofs of various features of the method, including the limiting behaviour for high signal-to-noise, where systematic model uncertainties dominate over noise errors. We find that the marginalised likelihood constructed via GPR offers a significant improvement in parameter estimation over the standard, uncorrected likelihood. We also examine the dependence of the method on the ...

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

    E-print Network

    Myers, Elim Rosalva

    2010-01-25

    Chemical process designs include safety factors to compensate for inherent parameter uncertainty in the design process. These safety factors require additional capital and operating expenses. Since these factors are based ...

  10. 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.

  11. a Study of the Mechanical Characteristics of Ultrasonic Cold Forged SKD61

    NASA Astrophysics Data System (ADS)

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

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

  12. 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

  13. 22 CFR 121.10 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings, and machined bodies. The U.S. Munitions List controls as defense articles those forgings, castings, and other unfinished products, such...

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

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

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

  15. Predicting parameters of degradation succession processes of Tibetan Kobresia grasslands

    NASA Astrophysics Data System (ADS)

    Lin, L.; Li, Y. K.; Xu, X. L.; Zhang, F. W.; Du, Y. G.; Liu, S. L.; Guo, X. W.; Cao, G. M.

    2015-08-01

    In the past two decades, increasing human activity (i.e., overgrazing) in the Tibetan Plateau has strongly influenced plant succession processes, resulting in the degradation of alpine grasslands. Therefore, it is necessary to diagnose the degree of degradation to enable implementation of appropriate management for sustainable exploitation and protection of alpine grasslands. Here, we investigated environmental factors and plant functional group quantity factors (PFGs) during the alpine grassland succession processes. Principal component analysis (PCA) was used to identify the parameters indicative of degradation. We divided the entire degradation process into six stages. PFG types shifted from rhizome bunch grasses to rhizome plexus and dense plexus grasses during the degradation process. Leguminosae and Gramineae plants were replaced by Sedges during the advanced stages of degradation. The PFGs were classified into two reaction groups: the grazing-sensitive group, containing Kobresia humilis Mey, and Gramineae and Leguminosae plants, and the grazing-insensitive group, containing Kobresia pygmaea Clarke. The first group was correlated with live root biomass in the surface soil (0-10 cm), whereas the second group was strongly correlated with mattic epipedon thickness and K. pygmaea characteristics. The degree of degradation of alpine meadows may be delineated by development of mattic epipedon and PFG composition. Thus, meadows could be easily graded and their use adjusted based on our scaling system, which would help prevent irreversible degradation of important grasslands. Because relatively few environmental factors are investigated, this approach can save time and labor to formulate a conservation management plan for degraded alpine meadows.

  16. Predicting parameters of degradation succession processes of Tibetan Kobresia grasslands

    NASA Astrophysics Data System (ADS)

    Lin, L.; Li, Y. K.; Xu, X. L.; Zhang, F. W.; Du, Y. G.; Liu, S. L.; Guo, X. W.; Cao, G. M.

    2015-11-01

    In the past two decades, increasing human activity (i.e., overgrazing) in the Tibetan Plateau has strongly influenced plant succession processes, resulting in the degradation of alpine grasslands. Therefore, it is necessary to diagnose the degree of degradation to enable implementation of appropriate management for sustainable exploitation and protection of alpine grasslands. Here, we investigated environmental factors and plant functional group (PFG) quantity factors during the alpine grassland succession processes. Principal component analysis (PCA) was used to identify the parameters indicative of degradation. We divided the entire degradation process into six stages. PFG types shifted from rhizome bunchgrasses to rhizome plexus and dense-plexus grasses during the degradation process. Leguminosae and Gramineae plants were replaced by sedges during the advanced stages of degradation. The PFGs were classified into two reaction groups: the grazing-sensitive group, containing Kobresia humilis Mey, and Gramineae and Leguminosae plants, and the grazing-insensitive group, containing Kobresia pygmaea Clarke. The first group was correlated with live root biomass in the surface soil (0-10 cm), whereas the second group was strongly correlated with mattic epipedon thickness and K. pygmaea characteristics. The degree of degradation of alpine meadows may be delineated by development of mattic epipedon and PFG composition. Thus, meadows could be easily graded and their use adjusted based on our scaling system, which would help prevent irreversible degradation of important grasslands. Because relatively few environmental factors are investigated, this approach can save time and labor to formulate a conservation management plan for degraded alpine meadows.

  17. 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...antidumping duty orders on heavy forged hand tools from China would be likely to lead...August 2011), entitled Heavy Forged Hand Tools From China: Investigation...

  18. 76 FR 168 - Heavy Forged Hand Tools From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-03

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

  19. Co-Operative Training in the Sheffield Forging Industry

    ERIC Educational Resources Information Center

    Duncan, R.

    2008-01-01

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

  20. Improving gravitational-wave parameter estimation using Gaussian process regression

    E-print Network

    Christopher J. Moore; Christopher P. L. Berry; Alvin J. K. Chua; Jonathan R. Gair

    2015-09-14

    Folding uncertainty in theoretical models into Bayesian parameter estimation is necessary in order to make reliable inferences. A general means of achieving this is by marginalising over model uncertainty using a prior distribution constructed using Gaussian process regression (GPR). Here, we apply this technique to (simulated) gravitational-wave signals from binary black holes that could be observed using advanced-era gravitational-wave detectors. Unless properly accounted for, uncertainty in the gravitational-wave templates could be the dominant source of error in studies of these systems. We explain our approach in detail and provide proofs of various features of the method, including the limiting behaviour for high signal-to-noise, where systematic model uncertainties dominate over noise errors. We find that the marginalised likelihood constructed via GPR offers a significant improvement in parameter estimation over the standard, uncorrected likelihood. We also examine the dependence of the method on the size of training set used in the GPR; on the form of covariance function adopted for the GPR, and on changes to the detector noise power spectral density.

  1. Parameter and process significance in mechanistic modeling of cellulose hydrolysis.

    PubMed

    Rotter, B E; Barry, D A; Gerhard, J I; Small, J S

    2008-09-01

    A process-based model relevant to landfill and anaerobic digesters was developed, which included a novel approach to biomass transfer between a cellulose-bound biofilm and biomass in the bulk liquid. Model results highlighted the significance of the bacterial colonization of cellulose particles by attachment through contact in solution. Simulations revealed that both enhanced colonization and cellulose degradation are associated with reduced cellulose particle size, increased biomass populations in solution and increased cellulose-binding ability of the biomass. This suggests that transportation of biomass into the system from elsewhere and/or bacterial inoculation of such systems could enhance degradation significantly. A sensitivity analysis of the system parameters revealed the biological rate and yield properties of the hydrolyzing bacteria are most significant with regard to cellulose degradation in the system. PMID:18055198

  2. 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.

  3. Forging Inclusive Solutions: Experiential Earth Charter Education

    ERIC Educational Resources Information Center

    Hill, Linda D.

    2010-01-01

    Forging Inclusive Solutions describes the aims, methodology and outcomes of Inclusive Leadership Adventures, an experiential education curriculum for exploring the Earth Charter. Experiential education builds meaningful relationships, skills, awareness and an inclusive community based on the Earth Charter principles. When we meet people where they…

  4. Forging the Link: Linking the Economic Incentives

    E-print Network

    Forging the Link: Linking the Economic Incentives of Low Impact Development with Community is an ideal follow-up to many introductory presentations on low impact development strategies as it details of Low Impact Development and Community Decisions · www.unh.edu/unhsc/forgingthelink/ Contact: Robert M

  5. Modeling Machining Distortion of Aircraft-Engine Disk Forgings

    NASA Astrophysics Data System (ADS)

    Yin, Yanling; Wu, Wei-Tsu; Srivatsa, Shesh; Semiatin, S. Lee; Gayda, John

    2004-06-01

    Rotating components of aircraft engines are generally manufactured by forging followed by heat treatment. Due to the residual stresses induced during heat treatment, components often distort when material is removed during machining to the final shape. Using trial-and-error approaches, it can be very difficult to develop a sequence of machining operations which will ensure that the final component is produced within the very tight dimensional tolerances required for satisfactory performance in service. The objective of the current work, therefore, was to develop and validate a simulation procedure that can predict distortion during the material removal process. To validate the model, four prototype disks were forged and then heat treated under different conditions. Multiple machining cuts were carried out on the top side of each disk. The distortion at the bottom surface was then measured. The Finite-Element Method (FEM) embodied in the commercial software, DEFORM™-HT, was used to model the four heat-treatment processes. Excellent agreement between the measured distortions and the finite-element predictions was found. The FEM heat-treatment model was shown to be a very useful tool to understand and predict distortion and can thus be used for the design and optimization of heat-treatment and machining processes.

  6. Sinter-forging conditions, texture and transport properties of Bi-2212 superconductors

    NASA Astrophysics Data System (ADS)

    Caillard, R.; Garnier, V.; Desgardin, G.

    2000-12-01

    The optimization of the sinter-forging process of the Bi-Sr-Ca-Cu-O (2212) superconducting ceramic, synthesized by a polymer matrix method has been done. The precursor powder was pressed under uniaxial stresses ranging between 15.9 and 46.8 MPa, and heated between 830°C and 845°C. Rather well textured samples showing less than 5.6 disorientation degrees for 50% of the grain respect to the ab plane have been obtained. The relationships between the stress value as well as the sinter-forging temperature and the samples texture have been correlated with the critical current densities, Jc, at 77 K. Maximum Jc close to 700 A cm -2 have been achieved with a pressure of 31.4 MPa and a temperature of 840°C showing that annealing under O 2/N 2 has also to be optimized to obtain in such sinter-forged bulk materials higher Jc values.

  7. Fracture behavior of tungsten wire reinforced superalloy composites during isothermal forging

    SciTech Connect

    Kandeil, A.Y.; Immarigeon, J.P.A.; Wallace, W.

    1984-03-01

    Mazzei et al. (1976) have reported a study of the processing of composite samples of Mar-M200 nickel-base superalloy reinforced with high strength tungsten wires. The use of these materials in industrial gas turbine engines for hot section blades and vanes was being considered. It was thought that isothermal forging might be necessary to complete the shaping and sizing operations, and studies related to the isothermal forging of these materials were conducted. Kandeil et al. (1982) have described some results on the flow and fracture behavior of these composites. The present investigation has the objective to examine the fracture of the materials in more detail, and to evaluate the results in terms of the practical forging of turbine airfoil shapes. 18 references.

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

    NASA Astrophysics Data System (ADS)

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

    1986-03-01

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

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

    SciTech Connect

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

    1986-03-01

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

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

    NASA Astrophysics Data System (ADS)

    Smolik, Jerzy

    2011-06-01

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

  11. Retrofitting forge shop furnaces for energy conservation

    SciTech Connect

    West, J.

    1982-07-01

    Case histories and energy-saving considerations involving furnaces for heating to forging and heat treating temperatures are described. It is shown that by refurbishing existing forge furnaces with improved insulation/tight seals; high velocity, combination fuel burners; 800/degree/F (427/degree/C) recuperation and appropriate temperature and pressure controls, significantly higher furnace efficiencies - in the 20% + range - can be achieved economically. Also, by refurbishing heat treating furnaces with improved insulation (typically ceramic fiber)/tight seals; high velocity, combination fuel burners with on ratio, proportional control; 800/degree/F (427/degree/C) recuperation and appropriate temperature and pressure controls substantial fuel reductions can result, with low capital expenditures.

  12. Automated, robotized forge-press systems viewed

    NASA Astrophysics Data System (ADS)

    Khmelnitskiy, M. N.

    1985-03-01

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

  13. Optimized process parameters for fabricating metal particles reinforced 5083 Al composite by friction stir processing

    PubMed Central

    Bauri, Ranjit; Yadav, Devinder; Shyam Kumar, C.N.; Janaki Ram, G.D.

    2015-01-01

    Metal matrix composites (MMCs) exhibit improved strength but suffer from low ductility. Metal particles reinforcement can be an alternative to retain the ductility in MMCs (Bauri and Yadav, 2010; Thakur and Gupta, 2007) [1,2]. However, processing such composites by conventional routes is difficult. The data presented here relates to friction stir processing (FSP) that was used to process metal particles reinforced aluminum matrix composites. The data is the processing parameters, rotation and traverse speeds, which were optimized to incorporate Ni particles. A wide range of parameters covering tool rotation speeds from 1000 rpm to 1800 rpm and a range of traverse speeds from 6 mm/min to 24 mm/min were explored in order to get a defect free stir zone and uniform distribution of particles. The right combination of rotation and traverse speed was found from these experiments. Both as-received coarse particles (70 ?m) and ball-milled finer particles (10 ?m) were incorporated in the Al matrix using the optimized parameters. PMID:26566541

  14. Optimized process parameters for fabricating metal particles reinforced 5083 Al composite by friction stir processing.

    PubMed

    Bauri, Ranjit; Yadav, Devinder; Shyam Kumar, C N; Janaki Ram, G D

    2015-12-01

    Metal matrix composites (MMCs) exhibit improved strength but suffer from low ductility. Metal particles reinforcement can be an alternative to retain the ductility in MMCs (Bauri and Yadav, 2010; Thakur and Gupta, 2007) [1,2]. However, processing such composites by conventional routes is difficult. The data presented here relates to friction stir processing (FSP) that was used to process metal particles reinforced aluminum matrix composites. The data is the processing parameters, rotation and traverse speeds, which were optimized to incorporate Ni particles. A wide range of parameters covering tool rotation speeds from 1000 rpm to 1800 rpm and a range of traverse speeds from 6 mm/min to 24 mm/min were explored in order to get a defect free stir zone and uniform distribution of particles. The right combination of rotation and traverse speed was found from these experiments. Both as-received coarse particles (70 ?m) and ball-milled finer particles (10 ?m) were incorporated in the Al matrix using the optimized parameters. PMID:26566541

  15. Influence of Process Parameter on Grit Blasting as a Pretreatment Process for Thermal Spraying

    NASA Astrophysics Data System (ADS)

    Bobzin, K.; Öte, M.; Linke, T. F.; Sommer, J.; Liao, X.

    2015-09-01

    In thermal spraying, uncoated substrates usually require roughening. As the most common roughening method, grit blasting increases the surface area and produces undercuts in almost all cases, which facilitate mechanical interlocking and thus promote the bonding between the substrate and coating. The effects of grit blasting parameters, i.e., the particle size, the blasting angle, the stand-off distance, and the pressure, on the resulting surface topography are investigated. Furthermore, the efficiency and wear behavior of the blasting media are analyzed. Influences of three different blasting media, corundum, alumina zirconia, and steel shot, on the surface roughening, are compared. By varying adjusted blasting parameters, different initial conditions (surface topography) are created. Subsequently, the substrate is coated, and the coating bond strength is measured. One of the main results of this publication is that alumina zirconia and steel grit show a longer lifetime than pure alumina as a blasting media. Moreover, it has been shown that the blasting parameters such as grain size, working pressure, and history (wear status) of the abrasive particles have a significant effect on the resulting surface topography. Additionally, systematical analysis in this study shows that the blasting parameters such as stand-off distance and blasting angle have a small influence on the results of the blasting process. Another important conclusion of this study is that the conventional surface parameters that have been analyzed in this study did not turn out to be suitable for describing the relationship between the surface topography of the substrate and resulting bond strength.

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

    NASA Astrophysics Data System (ADS)

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

    2002-12-01

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

  17. 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...

  18. 75 FR 67110 - Forged Stainless Steel Flanges From India and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-01

    ...640 (Third Review)] Forged Stainless Steel Flanges From India and Taiwan...antidumping duty orders on forged stainless steel flanges from India and Taiwan...antidumping duty orders on forged stainless steel flanges from India and...

  19. Direct cosmological evolution process research via new parameters' phase space

    E-print Network

    Jing-Zhao Qi; Ming-Jian Zhang; Wen-Biao Liu

    2015-05-14

    A new perspective on phase space analysis is described, based on which the well-known quintessence cosmology is studied with an exponential potential $V(\\phi)=V_{0}\\exp(-\\lambda\\phi)$. Different from the traditional phase space analysis, the cosmological parameters' space is employed in this method. A comparison of them is made to demonstrate the advantages of this new perspective. The whole evolution history of the universe can be displayed in the cosmological parameters' space analysis. Given observational data, the current state of universe could be pinpointed in phase diagrams, thus making the diagrams more informative. We also find that the evolution of universe will be discontinuous with inappropriate initial conditions. Subsequently, a numerical method is used to calculate possible valid ranges of the initial conditions, which indicate the initial value of $\\lambda$ should be small but not arbitrary. In addition, we obtain the evolutions of cosmological parameters that are in agreement with those given by the phase space analysis. Moreover, the calculation method of EoS parameter $w(a)$ is also improved.

  20. Fatigue behavior of rolled and forged tungsten at 25°, 280° and 480 °C

    NASA Astrophysics Data System (ADS)

    Habainy, J.; Iyengar, S.; Lee, Y.; Dai, Y.

    2015-10-01

    Pure tungsten has been chosen as the target material at the European Spallation Source facility in Lund. Calculations show that the target temperature can reach 500 °C momentarily during the spallation process, leading to thermal fatigue. Target life estimations require fatigue data at different temperatures and this work focuses on generating such data for pure, unirradiated, rolled and forged tungsten in the range 25°-480 °C. For specimens oriented in the rolling direction, tensile tests at room temperature indicated Young's modulus values in the range 320-390 GPa, low levels of plasticity (<0.23%) and UTS values in the range 397 MPa (unpolished) and 705 MPa (Polished). UTS for forged specimens were around 500 MPa. Stress-controlled fatigue tests were conducted in the tensile regime, with a runout limit of 2 × 106 cycles. At 25 °C, unpolished specimens had fatigue limits of 150 MPa (rolling and transverse direction), and 175 MPa (forged). For polished specimens in the rolling direction, fatigue limits were higher at 237.5 MPa (25 °C) and 252.5 MPa (280 °C). The forged specimens showed slightly better fatigue properties and marginal cyclic hardening at 480 °C.

  1. Quench-Induced Stresses in AA2618 Forgings for Impellers: A Multiphysics and Multiscale Problem

    NASA Astrophysics Data System (ADS)

    Chobaut, Nicolas; Saelzle, Peter; Michel, Gilles; Carron, Denis; Drezet, Jean-Marie

    2015-05-01

    In the fabrication of heat-treatable aluminum parts such as AA2618 compressor impellers for turbochargers, solutionizing and quenching are key steps to obtain the required mechanical characteristics. Fast quenching is necessary to avoid coarse precipitation as it reduces the mechanical properties obtained after heat treatment. However, fast quenching induces residual stresses that can cause unacceptable distortions during machining. Furthermore, the remaining residual stresses after final machining can lead to unfavorable stresses in service. Predicting and controlling internal stresses during the whole processing from heat treatment to final machining is therefore of particular interest to prevent negative impacts of residual stresses. This problem is multiphysics because processes such as heat transfer during quenching, precipitation phenomena, thermally induced deformations, and stress generation are interacting and need to be taken into account. The problem is also multiscale as precipitates of nanosize form during quenching at locations where the cooling rate is too low. This precipitation affects the local yield strength of the material and thus impacts the level of macroscale residual stresses. A thermomechanical model accounting for precipitation in a simple but realistic way is presented. Instead of modelling precipitation that occurs during quenching, the model parameters are identified using a limited number of tensile tests achieved after representative interrupted cooling paths in a Gleeble machine. The simulation results are compared with as-quenched residual stresses in a forging measured by neutron diffraction.

  2. Improved Hydrogeophysical Parameter Estimation from Empirical Mode Decomposition Processed Ground Penetrating Radar Data

    E-print Network

    Knapp, Camelia Cristina

    an accurate ground water model, especially in the case of contaminant flow prediction. Standard methods whereas ground water flow problems are two-and three- dimensional. Hydrogeophysical parameters estimatedImproved Hydrogeophysical Parameter Estimation from Empirical Mode Decomposition Processed Ground

  3. View west of small tooling and forging dies in Blacksmith ...

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

    View west of small tooling and forging dies in Blacksmith Shop, Boilermakers Department, east side of building 57; during World War II approximately forty women were employed as blacksmith's forging a variety of small tools; these may be the tools they used. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Structure Shop, League Island, Philadelphia, Philadelphia County, PA

  4. 76 FR 50755 - Heavy Forged Hand Tools From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

    ... determined on April 8, 2011 that it would conduct expedited reviews (76 FR 31631, June 1, 2011). The... Heavy Forged Hand Tools From China Determinations On the basis of the record \\1\\ developed in the... antidumping duty orders on heavy forged hand tools from China would be likely to lead to continuation...

  5. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... IMPLEMENTS OF WAR The U.S. Munitions Import List § 447.22 Forgings, castings, and machined bodies. Articles on the U.S. Munitions Import List include articles in a partially completed state (such as forgings... identifiable as defense articles. If the end-item is an article on the U.S. Munitions Import List,...

  6. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... IMPLEMENTS OF WAR The U.S. Munitions Import List § 447.22 Forgings, castings, and machined bodies. Articles on the U.S. Munitions Import List include articles in a partially completed state (such as forgings... identifiable as defense articles. If the end-item is an article on the U.S. Munitions Import List,...

  7. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... IMPLEMENTS OF WAR The U.S. Munitions Import List § 447.22 Forgings, castings, and machined bodies. Articles on the U.S. Munitions Import List include articles in a partially completed state (such as forgings... identifiable as defense articles. If the end-item is an article on the U.S. Munitions Import List,...

  8. 22 CFR 121.10 - Forgings, castings and machined bodies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings and machined bodies. Articles on the U.S. Munitions List include articles in a partially completed state (such as forgings... identifiable as defense articles. If the end-item is an article on the U.S. Munitions List...

  9. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... IMPLEMENTS OF WAR The U.S. Munitions Import List § 447.22 Forgings, castings, and machined bodies. Articles on the U.S. Munitions Import List include articles in a partially completed state (such as forgings... identifiable as defense articles. If the end-item is an article on the U.S. Munitions Import List,...

  10. 22 CFR 121.10 - Forgings, castings and machined bodies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings and machined bodies. Articles on the U.S. Munitions List include articles in a partially completed state (such as forgings... identifiable as defense articles. If the end-item is an article on the U.S. Munitions List...

  11. 22 CFR 121.10 - Forgings, castings and machined bodies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings and machined bodies. Articles on the U.S. Munitions List include articles in a partially completed state (such as forgings... identifiable as defense articles. If the end-item is an article on the U.S. Munitions List...

  12. 22 CFR 121.10 - Forgings, castings and machined bodies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings and machined bodies. Articles on the U.S. Munitions List include articles in a partially completed state (such as forgings... identifiable as defense articles. If the end-item is an article on the U.S. Munitions List...

  13. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... IMPLEMENTS OF WAR The U.S. Munitions Import List § 447.22 Forgings, castings, and machined bodies. Articles on the U.S. Munitions Import List include articles in a partially completed state (such as forgings... identifiable as defense articles. If the end-item is an article on the U.S. Munitions Import List,...

  14. 76 FR 168 - Heavy Forged Hand Tools From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-03

    ... antidumping duty order on imports of heavy forged hand tools from China (65 FR 48962). Following second five... continuation of the antidumping duty orders on imports of heavy forged hand tools from China (71 FR 8276). The... part 207), as most recently amended at 74 FR 2847 (January 16, 2009). \\1\\ No response to this...

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

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

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

  16. 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.

  17. INTERVAL APPROACH TO IDENTIFICATION OF PARAMETERS OF EXPERIMENTAL PROCESS

    E-print Network

    Sainudiin, Raazesh

    Symposium GAMM­IMACS (SCAN'2012) September 23­29, 2012 Institute of Computational Technologies, Siberian of the experimental process [2 - 4] Polynomial: S(t) = At3 + Bt2 + Ct + D, A > 0. Single exponent: S(t) = A exp corruption As a result, one should work under conditions of uncertainty. The fol- lowing practical

  18. Structure of magnesium alloy MA14 after multistep isothermal forging and subsequent isothermal rolling

    NASA Astrophysics Data System (ADS)

    Nugmanov, D. R.; Sitdikov, O. Sh.; Markushev, M. V.

    2015-10-01

    Optical metallography and electron microscopy have been used to analyze the structural changes in magnesium MA14 alloy subjected to processing that combines multistep isothermal forging and isothermal rolling. It has been found that forging of a bulk workpiece leads to the formation of a structure, 85-90% of which consists of recrystallized grains with an average size of less than 5 µm. Subsequent rolling results in a completely recrystallized structure with a grain size of 1-2 µm. It is shown that the resultant structural states are characterized by grain size nonuniformity inherited from the initial hot-pressed semi-finished product. The nature and features of crystallization processes that take place in the alloy during processing are discussed.

  19. 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.

  20. Dimensionless Numbers Expressed in Terms of Common CVD Process Parameters

    NASA Technical Reports Server (NTRS)

    Kuczmarski, Maria A.

    1999-01-01

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

  1. 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

  2. Hot Superplastic Powder Forging for Transparent nanocrystalline Ceramics

    SciTech Connect

    Cannon, W. Roger

    2006-05-22

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

  3. 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.

  4. Geomechanical Parameters in Fracturing Process of Layered Rocks

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  5. Factors Affecting Scale Adhesion on Steel Forgings

    NASA Astrophysics Data System (ADS)

    Zitterman, J. A.; Bacco, R. P.; Boggs, W. E.

    1982-04-01

    Occasionally, undesirable "sticky" adherent scale forms on low-carbon steel during reheating for hot forging. The mechanical abrading or chemical pickling required to remove this scale adds appreciably to the fabrication cost. Characterization of the steel-scale system by metallographic examination, x-ray diffraction, and electron-probe microanalysis revealed that nickel, silicon, and/or sulfur might be involved in the mechanism of sticky-scale formation. Laboratory reheating tests were conducted on steels with varied concentrations of nickel and silicon in atmospheres simulating those resulting from burning natural gas or sulfur-bearing fuels. Subsequent characterization of the scale formed during the tests tends to confirm that the composition of the steel, especially increased nickel and silicon contents, and the presence of the sulfur in the furnace atmosphere cause the formation of this undesirable scale.

  6. 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.

  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. T3PS v1.0: Tool for Parallel Processing in Parameter Scans

    NASA Astrophysics Data System (ADS)

    Maurer, Vinzenz

    2016-01-01

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

  9. Quenching of aerospace forgings from high temperatures using air-assisted, atomized water sprays

    NASA Astrophysics Data System (ADS)

    de Oliveira, M.; Ward, J.; Garwood, D. R.; Wallis, R. A.

    2002-02-01

    The nickel-based superalloy or titanium materials used in the aerospace industry are cooled from high temperatures during the heat treatment process to obtain appropriate strength properties. However, unacceptably high residual stresses can be developed in some situations if the rate of cooling is too high so that air-assisted, atomized water sprays have been suggested as an alternative to the widely used techniques of quenching in oil or water. Thus, this article examines two aspects of the use of air-water sprays for quenching aeroengine forgings. First, basic experimental heat transfer data are presented for a wide range of water flows and for surface temperatures up to approximately 850 °C, for both plane and recessed surfaces. Second, the heat transfer data are used in numerical simulations to study the influence of nonuniform spray distributions on the residual stress patterns in a typical forging.

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

    NASA Astrophysics Data System (ADS)

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

    2004-01-01

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

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

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

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

  12. Critical current densities in Bi-2223 sinter forgings.

    SciTech Connect

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

    1999-07-23

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

  13. Sintered and forged article and method of forming same

    SciTech Connect

    Cook, J.P.; Banerjee, B.R.

    1984-11-27

    An embodiment of the article comprises a metallic body formed, by a powder metallurgy technique, of steel powder and tungsten carbide particles, and forged, having a total density of not less than one hundred percent. The method, then, comprises the powder metallurgy steps of forming and sintering the body, and the subsequent forging step, to produce the one hundred percent total density steel and tungsten carbide article.

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

    PubMed

    Thiry, J; Krier, F; Evrard, B

    2015-02-01

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

  15. 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...

  16. 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 ...

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

    E-print Network

    Ko, Kyungduk

    2005-11-01

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

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

    E-print Network

    Kosanovic, D.; Ambs, L.

    2000-01-01

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

  19. 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.

  20. COMPARATIVE DURABILITY STUDY OF COMPETING MANUFACTURING PROCESS TECHNOLOGIES

    E-print Network

    Fatemi, Ali

    and castings, cast iron, and sintered powder forgings. It is not unusual to find a range of different materials competing manufacturing processes are steel forging and powder metal. Both components are fatigue critical) and another for an engine component (connecting rod). The steering knuckles evaluated included forged steel

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

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  3. Superplastic forging of aluminum 6061-silicon carbide(P) composites

    NASA Astrophysics Data System (ADS)

    Memongkol, Napisporn

    This work describes the processing and characterization of mechanically alloyed Al6061-SiCP composites. The SiC dispersion strengthened Al6061 was synthesized by mechanical alloying of SiC powder and Al6061 powder in an argon atmosphere followed by hot pressing or cold compaction and sinter forging in air. The microstructure of the Al-SiC composites showed a fine grain size of Al matrix with SiC particles and dispersoids distributed homogeneously in the Al matrix. The microstructure of unreinforced MA6061 showed a fine grain size with small dispersoids. The preferred orientation in these composites was measured using the neutron diffraction technique. The hot pressed material had a random texture while a <111> preferred texture was developed in the sinter forged samples. The amount of texture developed depends on the applied load but not on the sintering temperature. The compressive strengths of these composites (4%SiC and 8%SiC) were characterized in the temperatures range from 723 to 833K and at strain rates of 10-4 to 10-1 s-1 . The true compressive stress strain curves exhibit strain softening behavior. The results showed significantly higher strength than the base material. The strain rate sensitivity, m, from the compression test is much lower than required for superplastic behavior. Tensile tests on the MA Al-8%SiC composite and MA6061 monolithic material were performed at temperatures of 673, 723, and 773K and strain rates from 10-2 to 10 s-1 . The true tensile stress strain curves show the strain hardening behavior. The relationship between microstructure, texture, densification and mechanical properties was studied and the strengthening mechanisms were identified. Uniaxial consolidation experiments have been conducted at room temperature and elevated temperature for three different powders, Al6061, MA6061 and MA6061-8%SiC. The experiments illustrated that the densification mechanisms of the three different powders at room temperature are similar but they are different at elevated temperature.

  4. Influence of process parameters on threshold voltage and leakage current in 18nm NMOS device

    NASA Astrophysics Data System (ADS)

    Atan, Norani Binti; Ahmad, Ibrahim Bin; Majlis, Burhanuddin Bin Yeop; Fauzi, Izzati Binti Ahmad

    2015-04-01

    The process parameters are very crucial factor in the development of transistors. There are many process parameters that influenced in the development of the transistors. In this research, we investigate the effects of the process parameters variation on response characteristics such as threshold voltage (VTH) and sub-threshold leakage current (IOFF) in 18nm NMOS device. The technique to identify semiconductor process parameters whose variability would impact most on the device characteristic is realized through the process by using Taguchi robust design method. This paper presents the process parameters that influenced in threshold voltage (VTH) and sub-threshold leakage current (IOFF) which includes the Halo Implantation, Compensation Implantation, Adjustment Threshold voltage Implantation and Source/Drain Implantation. The design, fabrication and characterization of 18nm HfO2/TiSi2 NMOS device is simulated and performed via a tool called Virtual Wafer Fabrication (VWF) Silvaco TCAD Tool known as ATHENA and ATLAS simulators. These two simulators were combined with Taguchi L9 Orthogonal method to aid in the design and the optimization of the process parameters to achieve the optimum average of threshold voltage (VTH) and sub-threshold leakage current, (IOFF) in 18nm device. Results from this research were obtained; where Halo Implantation dose was identified as one of the process parameter that has the strongest effect on the response characteristics. Whereby the Compensation Implantation dose was identified as an adjustment factor to get the nominal values of threshold voltage VTH, and sub-threshold leakage current, IOFF for 18nm NMOS devices equal to 0.302849 volts and 1.9123×10-16 A/?m respectively. The design values are referred to ITRS 2011 prediction.

  5. Camera calibration method for dimensional measurement of heavy forging in large scale

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Hu, Chunhai; Song, Xiaoxue; Zhao, Zhenqing

    2009-07-01

    Camera calibration method plays an important role in the stereovision system to resolve the problems of dimensional measurement of heavy forging. Due to the intensive vibrating, the camera parameters must be calibrated every time after the action of the water press. This paper presents a method using the scene geometry to calibrate cameras. In the context of heavy machinery environments, the constraints which can be used are parallelism and orthogonality. These constraints lead to geometrically intuitive methods to calibrate the cameras. The huge forging equipment such as water press belongs to geometrically constrained object and insusceptible to vibrating, which gives natural prior knowledge and constraint conditions for 3-D reconstruction. The method focuses on the calibration of the extrinsic parameters which are subject to change since the effects of the workspace factors. The intrinsic parameters were calibrated in advance by an off-line method and were assumed as invariable. The results of simulation experiments demonstrate that the camera parameters could be calibrated effectively and achieve the real time need.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  7. PARAMETER SEARCH FOR AN IMAGE PROCESSING FUZZY C-MEANS HAND GESTURE RECOGNITION SYSTEM

    E-print Network

    Wachs, Juan

    times must be obtained for practical use [3]. Human-robot interaction using hand gestures providesPARAMETER SEARCH FOR AN IMAGE PROCESSING FUZZY C- MEANS HAND GESTURE RECOGNITION SYSTEM Juan Wachs a hand gesture recognition system using an optimized Image Processing-Fuzzy C-Means (FCM) algorithm

  8. A Hybrid ANN-BFOA Approach for Optimization of FDM Process Parameters

    NASA Astrophysics Data System (ADS)

    Sood, Anoop Kumar; Ohdar, R. K.; Mahapatra, S. S.

    This study proposes an integrated approach for effectively assisting the practitioners in prediction and optimization of process parameters of fused deposition modelling (FDM) process for improving the mechanical strength of fabricated part. The experimental data are used for efficiently training and testing artificial neural network (ANN) model that finely maps the relationship between the input process control factors and output responses. Bayesian regularization is adopted for selection of optimum network architecture because of its ability to fix number of network parameters irrespective of network size. ANN model is trained using Levenberg-Marquardt algorithm and the resulting network has good generalization capability that eliminates the chance of over fitting. Finally, ANN network is combined with bacterial-foraging optimization algorithm (BFOA) to suggest theoretical combination of parameter settings to improve strength related responses of processed parts.

  9. Effects of Arc Spray Process Parameters on Corrosion Resistance of Ti Coatings

    NASA Astrophysics Data System (ADS)

    Zhao, Wei-Min; Liu, Cun; Dong, Li-Xian; Wang, Yong

    2009-12-01

    In order to improve the corrosion resistance of carbon steel structures in marine environment, Ti wires were sprayed to a steel substrate using arc spray technique, and orthogonal experimental design was used to investigate the effects of the fluctuation in the main parameters of spray process on the microstructure and the corrosion resistance of sprayed coatings. The results show that the corrosion resistance of sprayed coatings is very sensitive to spray process parameters, corrosion current density can decrease from 997.7 to 5.08 ?A cm-2 by optimizing process parameters. The coatings are composed of TiN and Ti2O, and the corrosion resistance of coatings can be improved with the decrease in the contents of oxides. The spray distance should be exactly monitored and controlled in arc spray process because of its great effects on the quality of sprayed coatings.

  10. 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

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

    PubMed

    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

  12. 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.

  13. Catching sparks from well-forged neutralinos

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  14. DURABILITY COMPARISON AND LIFE PREDICTIONS OF COMPETING MANUFACTURING PROCESSES: AN EXPERIMENTAL STUDY OF

    E-print Network

    Fatemi, Ali

    , and powder forgings have found broad applications in automotive safety-critical systems like engine processes. These include forged steel, cast aluminum, and cast iron knuckles. Fatigue behavior is a key loading during its service life. Forging process was considered as the base for investigation and other

  15. Modelling of Viscoplastic Behaviour of IN718 Under Hot Forging Conditions

    SciTech Connect

    Lin, Y. P.; Lin, J.; Dean, T. A.; Brown, P. D.

    2007-04-07

    The mechanical properties of IN718 are directly related to microstructure such as grain size and the hardening mechanisms, which are effective during thermomechanical processing and subsequent heat treatment. In this study a set of unified viscoplastic constitutive equations were determined for IN718 from experimental data of hot forging conditions. Techniques were developed to analyse the reliability and consistency of the experimental data derived from different previous publications. In addition to viscoplastic flow of the material, the determined material model can be used to predict the evolution of dislocations, recrystallisation and grain size occurring during thermomechanical processing.

  16. On selecting a prior for the precision parameter of Dirichlet process mixture models

    USGS Publications Warehouse

    Dorazio, R.M.

    2009-01-01

    In hierarchical mixture models the Dirichlet process is used to specify latent patterns of heterogeneity, particularly when the distribution of latent parameters is thought to be clustered (multimodal). The parameters of a Dirichlet process include a precision parameter ?? and a base probability measure G0. In problems where ?? is unknown and must be estimated, inferences about the level of clustering can be sensitive to the choice of prior assumed for ??. In this paper an approach is developed for computing a prior for the precision parameter ?? that can be used in the presence or absence of prior information about the level of clustering. This approach is illustrated in an analysis of counts of stream fishes. The results of this fully Bayesian analysis are compared with an empirical Bayes analysis of the same data and with a Bayesian analysis based on an alternative commonly used prior.

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

    PubMed Central

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

    2015-01-01

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

  18. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

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

  1. Processing Parameters Optimization for Material Deposition Efficiency in Laser Metal Deposited Titanium Alloy

    NASA Astrophysics Data System (ADS)

    Mahamood, Rasheedat M.; Akinlabi, Esther T.

    2015-11-01

    Ti6Al4V is an important Titanium alloy that is mostly used in many applications such as: aerospace, petrochemical and medicine. The excellent corrosion resistance property, the high strength to weight ratio and the retention of properties at high temperature makes them to be favoured in most applications. The high cost of Titanium and its alloys makes their use to be prohibitive in some applications. Ti6Al4V can be cladded on a less expensive material such as steel, thereby reducing cost and providing excellent properties. Laser Metal Deposition (LMD) process, an additive manufacturing process is capable of producing complex part directly from the 3-D CAD model of the part and it also has the capability of handling multiple materials. Processing parameters play an important role in LMD process and in order to achieve desired results at a minimum cost, then the processing parameters need to be properly controlled. This paper investigates the role of processing parameters: laser power, scanning speed, powder flow rate and gas flow rate, on the material utilization efficiency in laser metal deposited Ti6Al4V. A two-level full factorial design of experiment was used in this investigation, to be able to understand the processing parameters that are most significant as well as the interactions among these processing parameters. Four process parameters were used, each with upper and lower settings which results in a combination of sixteen experiments. The laser power settings used was 1.8 and 3 kW, the scanning speed was 0.05 and 0.1 m/s, the powder flow rate was 2 and 4 g/min and the gas flow rate was 2 and 4 l/min. The experiments were designed and analyzed using Design Expert 8 software. The software was used to generate the optimized process parameters which were found to be laser power of 3.2 kW, scanning speed of 0.06 m/s, powder flow rate of 2 g/min and gas flow rate of 3 l/min.

  2. 76 FR 8773 - Forged Stainless Steel Flanges From India and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ...731-TA-639 and 640 (Third Review)] Forged Stainless Steel Flanges From India and Taiwan AGENCY: United States...revocation of the antidumping duty orders on forged stainless steel flanges from India and Taiwan would be likely to...

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  4. 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.

  5. A Study on Reactive Spray Deposition Technology Processing Parameters in the Context of Pt Nanoparticle Formation

    NASA Astrophysics Data System (ADS)

    Roller, Justin M.; Maric, Radenka

    2015-10-01

    Catalytic materials are complex systems in which achieving the desired properties (i.e., activity, selectivity and stability) depends on exploiting the many degrees of freedom in surface and bulk composition, geometry, and defects. Flame aerosol synthesis is a process for producing nanoparticles with ample processing parameter space to tune the desired properties. Flame dynamics inside the reactor are determined by the input process variables such as solubility of precursor in the fuel; solvent boiling point; reactant flow rate and concentration; flow rates of air, fuel and the carrier gas; and the burner geometry. In this study, the processing parameters for reactive spray deposition technology, a flame-based synthesis method, are systematically evaluated to understand the residence times, reactant mixing, and temperature profiles of flames used in the synthesis of Pt nanoparticles. This provides a framework for further study and modeling. The flame temperature and length are also studied as a function of O2 and fuel flow rates.

  6. Uncertainty in thermal process calculations due to variability in first-order and Weibull kinetic parameters.

    PubMed

    Halder, A; Datta, A K; Geedipalli, S S R

    2007-05-01

    Alternatives to first-order model of death kinetics of microorganisms have been proposed as improvements in the calculation of lethality for a thermal process. Although such models can potentially improve predictions for many situations, this article tries to answer the question of whether the added complexities of these models are a worthwhile investment once we include the effect of uncertainties in various microbiological and process parameters. Monte Carlo technique is used to include variability in kinetic parameters in lethality calculation for a number of heating processes, for both first-order and Weibull kinetics models. It is shown that uncertainties represented by coefficient of variation in kinetic parameters lead to a wide range of final log-reduction prediction. With the same percent variability in kinetic parameters, uncertainty in the final log reduction for Weibull kinetics was smaller or equal to that for first-order kinetics. Due to the large effect of variability in the input parameters on the final log reduction, the effort to move toward more accurate kinetic models needs to be weighed against inclusion of variability. PMID:17995767

  7. 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

    ...they operate the forging machines correctly and safely...estimate of the burden (time and costs) of the information...collection. Title: Forging Machines (29 CFR 1910.218...Biweekly. Average Time per Response: Varies...inspection of each forging machine and guard or...

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

    SciTech Connect

    Scarola, K.; Jamison, D.S.; Manazir, R.M.; Rescorl, R.L.; Harmon, V.; Harmon, D.L.

    1993-07-13

    A display device is described for indicating the value of a parameter in a process plant having an indicator and alarm system, comprising: a display screen; digital processing means for producing a plurality of display fields on the display screen, receiving input signals originating from sensors responsive to changes in the parameter, computing derived values from the input signals, and producing output value images in some of the display fields commensurate with respective input signals and derived values; some of said fields defining touch-sensitive selection means for selecting particular of said fields and particular of said values for display on said screen; herein a first set of said fields define a first display page and a second set of fields define a second display page, (a) the first and second display pages each having, a process value field for displaying one output value image, a quality field for displaying the quality of said one output value, a menu field defining a touch-sensitive menu selection target whereby the user can alternate the display between said first and second pages, (b) the first display page having, a plurality of touch-sensitive sensor fields for displaying the identity of each sensor that generates an input signal for said parameter, such that touching one of said sensor fields causes the display of the corresponding value image in said process value field, a touch sensitive calculation field for causing the display of a derived value of said parameter in said process value field, a touch sensitive over side field whereby the operator can specify which of the output values of said display device is to be used as a representative value of the parameter in the indicator and alarm system, (c) the second display page having an analog field in which at least one analog representation of the value in the process value field is displayed.

  9. Multiobjective optimization in structural design with uncertain parameters and stochastic processes

    NASA Technical Reports Server (NTRS)

    Rao, S. S.

    1984-01-01

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

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

    SciTech Connect

    Li, Xuefeng; Cao, Guangzhan; Liu, Hongjun

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

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

    NASA Technical Reports Server (NTRS)

    Roberts, F. E., III

    1995-01-01

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

  13. 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 Nabil Magbool Jan Guide : Dr. Sridharakumar Narasimhan Department of Chemical Engineering IIT Madras and nuc,dof = 0 (Existing) Design sensor networks using conven- tional methods such as maximizing

  14. An IRT Model with a Parameter-Driven Process for Change

    ERIC Educational Resources Information Center

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

    2005-01-01

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

  15. IEEE TRANSACTIONS ON IMAGE PROCESSING 1 Image Sensor Noise Parameter Estimation by

    E-print Network

    Hesser, Jürgen

    IEEE TRANSACTIONS ON IMAGE PROCESSING 1 Image Sensor Noise Parameter Estimation by Variance denoising requires taking into account the dependence of the noise distribution on the original image into an image with signal-independent noise. Principal component analysis of blocks of the transformed image

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    E-print Network

    Bailer-Jones, Coryn

    process control variables are the strain, strain rate and temperature, all of which may be functionsStatic and Dynamic Modelling of Materials Forging Coryn A.L. Bailer-Jones, David J.C. Mac processing of materials is an increasingly important requirement in many areas of engineering

  18. Theory and technology of sintering processes, thermal and thermochemical treatment

    SciTech Connect

    Dudnik, E.V.; Zuitseva, Z.A.; Shevchenko, A.V.; Lopato, L.M.

    1995-11-01

    The authors consider the effect of the starting powder characteristics (purity, grain size and shape, size distribution, sintering aids content, etc.), green compact microstructure (density and porosity distribution), and processing parameters (including temperature, exposure time, rate of heating or cooling of the medium) on sintering of ultrafine ZrO{sub 2}-based powders. They discuss various sintering techniques: hydrothermal sintering, microwave sintering, hot pressing, sinter-forging, sinter-HIP, and gas-pressure sintering.

  19. 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.

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

    SciTech Connect

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

    2015-04-24

    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 (I{sub LEAK}) 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 (TiO{sub 2}) and tungsten silicide (WSi{sub x}). 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 I{sub LEAK} where the maximum predicted I{sub LEAK} 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 I{sub LEAK} mean value of 3.96821 nA/µm where is far lower than the predicted value.

  1. 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.

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

    PubMed

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

    2014-04-01

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

  3. Fault detection in heavy duty wheels by advanced vibration processing techniques and lumped parameter modeling

    NASA Astrophysics Data System (ADS)

    Malago`, M.; Mucchi, E.; Dalpiaz, G.

    2016-03-01

    Heavy duty wheels are used in applications such as automatic vehicles and are mainly composed of a polyurethane tread glued to a cast iron hub. In the manufacturing process, the adhesive application between tread and hub is a critical assembly phase, since it is completely made by an operator and a contamination of the bond area may happen. Furthermore, the presence of rust on the hub surface can contribute to worsen the adherence interface, reducing the operating life. In this scenario, a quality control procedure for fault detection to be used at the end of the manufacturing process has been developed. This procedure is based on vibration processing techniques and takes advantages of the results of a lumped parameter model. Indicators based on cyclostationarity can be considered as key parameters to be adopted in a monitoring test station at the end of the production line due to their not deterministic characteristics.

  4. 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.

  5. Application of CBR method for adding the process of cutting tools and parameters selection

    NASA Astrophysics Data System (ADS)

    Ociepka, P.; Herbus, K.

    2015-11-01

    Modem enterprises must face with the dynamically changing market demand what influences the designing process. It is possible by linking computer tools with information gathered by experienced designers teams. The article describes the method basing on engineering knowledge and experience to adding the process of tools selection and cutting parameters determination for a turning operation. The method, proposed by the authors, is based on the CBR (Case Based Reasoning) method. CBR is a method of problem solving that involves searching for an analogy (similarity) between the current task to be solved, and the earlier cases that properly described, are stored in a computer memory. This article presents an algorithm and a formalized description of the developed method. It was discussed the range of its utilization, as well as it was illustrated the method of its functioning on the example of the tools and cutting parameters selection with respect to the turning process.

  6. 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,…

  7. 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...

  8. My Insanely Great Paper Prospectus Geordi LaForge

    E-print Network

    Dahlquist, Kam D.

    My Insanely Great Paper Prospectus Geordi LaForge 1 Option 1: In-Depth Study For my operating systems research paper, I would like to do an in-depth study on the high-capacity nonvolatile storage is no larger than an average human head and requires modest power. The paper will discuss the basic concepts

  9. 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,…

  10. Electronic Portfolios in Teacher Education: Forging a Middle Ground

    ERIC Educational Resources Information Center

    Strudler, Neal; Wetzel, Keith

    2012-01-01

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

  11. 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…

  12. 51. INTERIOR VIEW OF BLACKSMITH SHOP SHOWING OVEN AND FORGE, ...

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

    51. INTERIOR VIEW OF BLACKSMITH SHOP SHOWING OVEN AND FORGE, WITH ANVIL IN BACKGROUND; NOTE THE COIL SPRINGS AND CUTTING KNIVES ON FLOOR, MATERIALS ARE EXTENSIVELY REUSED BY THE BLACKSMITH - LaBelle Iron Works, Thirtieth & Wood Streets, Wheeling, Ohio County, WV

  13. Consolidation and Forging Methods for a Cryomilled Al Alloy

    NASA Astrophysics Data System (ADS)

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

    2008-09-01

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

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

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

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

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

    NASA Astrophysics Data System (ADS)

    Batzias, Dimitris F.; Ifanti, Konstantina

    2012-12-01

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

  17. Estimation of Temperature Dependent Parameters of a Batch Alcoholic Fermentation Process

    NASA Astrophysics Data System (ADS)

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

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

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

    NASA Astrophysics Data System (ADS)

    Weiss, Claire Victoria

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

  19. Simulation, part path correction, and automated process parameter selection for ultrashort pulsed laser micromachining of sapphire

    NASA Astrophysics Data System (ADS)

    Blood, Daniel A.

    This dissertation describes an ultrashort pulsed laser material removal simulator with X-Y stage acceleration profile consideration and part path compensation. Ultrashort pulsed lasers offer the advantage of single step processing of various materials with high repeatability. Over the past 30 years the laser repetition rate and power output have increased, and although this increases the material removal rate, it also introduces new challenges. The acceleration rates of the X-Y stages on a laser micromachining setup are finite, but this has been neglected. In the past the acceleration rate has been negligible due to low repetition rates; however, for high repetition rates the acceleration and deceleration regions introduce local variations in the material removal. A novel method is presented that accounts for the stage dynamics to produce a more robust simulated cut. In addition to the simulator, a technique for modifying the part path to reduce non-uniformity in the material removal is discussed. The laser operator has access to a variety of process parameters that ultimately affect the cost and quality of the machined component. Choosing the correct combination of these parameters requires knowledge of the machining process, and the wrong combination can result in a feature that is unsatisfactory and/or overly expensive. The modification of these parameters, and a correction of the part path allows for a more uniform depth of cut and higher feature quality. This dissertation contains three main contributions. The first contribution is to quantify the relationship between ultrashort pulsed laser machining parameters and the ablation depth of sapphire. The second is to produce a pulsed laser micromachining simulator that includes not only the laser-material interaction, but also the nuances of controlling the position of the laser beam on the workpiece. The final contribution is to produce a part path correction program with an automated process parameter routine. This program simplifies the process parameter selection and reduces depth irregularities in the machined geometry. Ultrashort pulsed lasers are a relatively new laser type; consequently, there is a plethora of aspects that may be added into future iterations of the simulator, automated parameter selection routine, and part path correction software. These aspects include, but are not limited to: sidewall angle compensation, thermal diffusion modeling, and modeling of additional workpiece materials.

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

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  1. D f ti P iDeformation Processing ME 4210: Manufacturing Processes and Engineering

    E-print Network

    Colton, Jonathan S.

    D f ti P iDeformation Processing ver. 1 ME 4210: Manufacturing Processes and Engineering Prof. J drawingWire drawing · Extrusion R lli· Rolling ME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton © GIT 2009 2 #12;ForgingForging ME 4210: Manufacturing Processes and Engineering Prof. J.S. Colton

  2. Optimization of process parameters for pulsed laser milling of micro-channels on AISI H13 tool steel

    E-print Network

    Ozel, Tugrul

    Optimization of process parameters for pulsed laser milling of micro-channels on AISI H13 tool selection Laser milling process a b s t r a c t This paper focuses on understanding the influence of laser milling process parameters on the final geometrical and surface quality of micro-channel features

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

    DOEpatents

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

    1985-01-01

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

  5. Determination of poly(epsilon-caprolactone) solubility parameters: application to solvent substitution in a microencapsulation process.

    PubMed

    Bordes, C; Fréville, V; Ruffin, E; Marote, P; Gauvrit, J Y; Briançon, S; Lantéri, P

    2010-01-01

    The evolution of regulation on chemical substances (i.e. REACH regulation) calls for the progressive substitution of toxic chemicals in formulations when suitable alternatives have been identified. In this context, the method of Hansen solubility parameters was applied to identify an alternative solvent less toxic than methylene chloride used in a microencapsulation process. During the process based on a multiple emulsion (W/O/W) with solvent evaporation/extraction method, the solvent has to dissolve a polymer, poly(epsilon-caprolactone) (PCL), which forms a polymeric matrix encapsulating or entrapping a therapeutic protein as the solvent is extracted. Therefore the three partial solubility parameters of PCL have been determined by a group contribution method, swelling experiments and turbidimetric titration. The results obtained allowed us to find a solvent, anisole, able to solubilize PCL and to form a multiple emulsion with aqueous solutions. A feasibility test was conducted under standard operating conditions and allowed the production of PCL microspheres. PMID:19781605

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

    NASA Astrophysics Data System (ADS)

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

    2006-11-01

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

  7. 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.

  8. Influence of in line monitored fluid bed granulation process parameters on the stability of Ethinylestradiol.

    PubMed

    Roßteuscher-Carl, Katrin; Fricke, Sabine; Hacker, Michael C; Schulz-Siegmund, Michaela

    2015-12-30

    Ethinylestradiol (EE) as a highly active and low dosed compound is prone to oxidative degradation. The stability of the drug substance is therefore a critical parameter that has to be considered during drug formulation. Beside the stability of the drug substance, granule particle size and moisture are critical quality attributes (CQA) of the fluid bed granulation process which influence the tableting ability of the resulting granules. Both CQA should therefore be monitored during the production process by process analytic technology (PAT) according to ICH Q8. This work focusses on the effects of drying conditions on the stability of EE in a fluid-bed granulation process. We quantified EE degradation products 6-alpha-hydroxy-EE, 6-beta-hydroxy-EE, 9(11)-dehydro-EE and 6-oxo-EE during long time storage and accelerated conditions. PAT-tools that monitor granule particle size (Spatial filtering technology) and granule moisture (Microwave resonance technology) were applied and compared with off-line methods. We found a relevant influence of residual granule moisture and thermic stress applied during granulation on the storage stability of EE, whereas no degradation was found immediately after processing. Hence we conclude that drying parameters have a relevant influence on long term EE stability. PMID:26541302

  9. Parameter-free effective field theory calculation for the solar proton-fusion and hep processes

    E-print Network

    T. -S. Park; L. E. Marcucci; R. Schiavilla; M. Viviani; A. Kievsky; S. Rosati; K. Kubodera; D. -P. Min; M. Rho

    2002-08-27

    Spurred by the recent complete determination of the weak currents in two-nucleon systems up to ${\\cal O}(Q^3)$ in heavy-baryon chiral perturbation theory, we carry out a parameter-free calculation of the threshold $S$-factors for the solar $pp$ (proton-fusion) and $hep$ processes in an effective field theory that {\\it combines} the merits of the standard nuclear physics method and systematic chiral expansion. The power of the EFT adopted here is that one can correlate in a unified formalism the weak-current matrix elements of two-, three- and four-nucleon systems. Using the tritium $\\beta$-decay rate as an input to fix the only unknown parameter in the theory, we can evaluate the threshold $S$ factors with drastically improved precision; the results are $S_{pp}(0) = 3.94\\times(1 \\pm 0.004) \\times 10^{-25} {MeV-b}$ and $S_{hep}(0) = (8.6\\pm 1.3)\\times 10^{-20} {keV-b}$. The dependence of the calculated $S$-factors on the momentum cutoff parameter $\\Lambda$ has been examined for a physically reasonable range of $\\Lambda$. This dependence is found to be extremely small for the $pp$ process, and to be within acceptable levels for the $hep$ process, substantiating the consistency of our calculational scheme.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

    Tumurugoti, Priyatham

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

  12. Cerebral processing of emotional prosody--influence of acoustic parameters and arousal.

    PubMed

    Wiethoff, Sarah; Wildgruber, Dirk; Kreifelts, Benjamin; Becker, Hubertus; Herbert, Cornelia; Grodd, Wolfgang; Ethofer, Thomas

    2008-01-15

    The human brain has a preference for processing of emotionally salient stimuli. In the auditory modality, emotional prosody can induce such involuntary biasing of processing resources. To investigate the neural correlates underlying automatic processing of emotional information in the voice, words spoken in neutral, happy, erotic, angry, and fearful prosody were presented in a passive-listening functional magnetic resonance imaging (fMRI) experiment. Hemodynamic responses in right mid superior temporal gyrus (STG) were significantly stronger for all emotional than for neutral intonations. To disentangle the contribution of basic acoustic features and emotional arousal to this activation, the relation between event-related responses and these parameters was evaluated by means of regression analyses. A significant linear dependency between hemodynamic responses of right mid STG and mean intensity, mean fundamental frequency, variability of fundamental frequency, duration, and arousal of the stimuli was observed. While none of the acoustic parameters alone explained the stronger responses of right mid STG to emotional relative to neutral prosody, this stronger responsiveness was abolished both by correcting for arousal or the conjoint effect of the acoustic parameters. In conclusion, our results demonstrate that right mid STG is sensitive to various emotions conveyed by prosody, an effect which is driven by a combination of acoustic features that express the emotional arousal in the speaker's voice. PMID:17964813

  13. Deep silicon etch for biology MEMS fabrication: review of process parameters influence versus chip design

    NASA Astrophysics Data System (ADS)

    Magis, T.; Ballerand, S.; Bellemin Comte, A.; Pollet, Olivier

    2013-03-01

    Micro-system for biology is a growing market, especially for micro-fluidic applications (environment and health). Key part for the manufacturing of biology MEMS is the deep silicon etching by plasma to create microstructures. Usual etching process as an alternation of etching and passivation steps is a well-known method for MEMS fabrication, nowadays used in high volume production for devices like sensors and actuators. MEMS for biology applications are very different in design compared to more common micro-systems like accelerometers for instance. Indeed, their design includes on the same chip structures of very diverse size like narrow pillars, large trenches and wide cavities. This makes biology MEMS fabrication very challenging for DRIE, since each type of feature considered individually would require a specific etch process. Furthermore process parameters suited to match specifications on small size features (vertical profile, low sidewall roughness) induce issues and defects on bigger structures (undercut, micro-masking) and vice versa. Thus the process window is constrained leading to trade-offs in process development. In this paper process parameters such as source and platen powers, pressure, etching and passivation gas flows and steps duration were investigated to achieve all requirements. As well interactions between those different factors were characterized at different levels, from individual critical feature up to chip scale and to wafer scale. We will show the plasma process development and tuning to reach all these specifications. We also compared different chambers configurations of our ICP tool (source wafer distance, plasma diffusion) in order to obtain a good combination of hardware and process. With optimized etching we successfully fabricate micro-fluidic devices like micro-pumps.

  14. Study on Surface Durability of Powder-Forged Rollers with Case-Hardening

    NASA Astrophysics Data System (ADS)

    Zhang, Qiang; Seki, Masanori; Ohue, Yuji; Yoshida, Akira; Murakami, Masahiro; Sato, Masaaki; Konishi, Masanari

    Powder forging (P/F), which combines powder metallurgy (P/M) and forging technologies, leads to refined poreless microstructure in the material. Therefore, the mechanical property of the P/F material can be greatly improved comparing with that of the sintered material. In this paper, the rolling contact fatigue tests were conducted using a two-cylinder testing machine, and the surface failure and durability of the case-hardened P/F rollers were compared with those of the case-hardened conventional steel rollers. From the experimental and analytical results, it could be concluded that the failure mode of the P/F and the steel rollers was mainly spalling, and the surface durability of the P/F rollers was almost the same as that of the steel rollers. Evaluating the rolling contact fatigue life by the amplitude of the ratio of orthogonal shear stress ? yz to Vickers hardness Hv, considering the case that every hardness distribution is the same to each other, the fatigue life of the Ni rich P/F roller was rather longer than that of the steel ones. The P/F process effectively improves the microstructure of the P/M material and makes the surface durability of the P/F material with high content of Ni approach to the level of steel. The P/F process was a good method to improve the mechanical properties of the sintered materials.

  15. 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

    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.

  16. Process optimization in high-average-power ultrashort pulse laser microfabrication: how laser process parameters influence efficiency, throughput and quality

    NASA Astrophysics Data System (ADS)

    Schille, Joerg; Schneider, Lutz; Loeschner, Udo

    2015-09-01

    In this paper, laser processing of technical grade stainless steel and copper using high-average-power ultrashort pulse lasers is studied in order to gain deeper insight into material removal for microfabrication. A high-pulse repetition frequency picosecond and femtosecond laser is used in conjunction with high-performance galvanometer scanners and an in-house developed two-axis polygon scanner system. By varying the processing parameters such as wavelength, pulse length, fluence and repetition rate, cavities of standardized geometry are fabricated and analyzed. From the depths of the cavities produced, the ablation rate and removal efficiency are estimated. In addition, the quality of the cavities is evaluated by means of scanning electron microscope micrographs or rather surface roughness measurements. From the results obtained, the influence of the machining parameters on material removal and machining quality is discussed. In addition, it is shown that both material removal rate and quality increase by using femtosecond compared to picosecond laser pulses. On stainless steel, a maximum throughput of 6.81 mm3/min is achieved with 32 W femtosecond laser powers; if using 187 W picosecond laser powers, the maximum is 15.04 mm3/min, respectively. On copper, the maximum throughputs are 6.1 mm3/min and 21.4 mm3/min, obtained with 32 W femtosecond and 187 W picosecond laser powers. The findings indicate that ultrashort pulses in the mid-fluence regime yield most efficient material removal. In conclusion, from the results of this analysis, a range of optimum processing parameters are derived feasible to enhance machining efficiency, throughput and quality in high-rate micromachining. The work carried out here clearly opens the way to significant industrial applications.

  17. 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.

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

    PubMed

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

    2015-03-15

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

  19. Using value stream mapping to improve forging processes

    E-print Network

    King, Stephen G. (Stephen George), 1974-

    2004-01-01

    Value stream mapping is a technique that uses icons to map the flow of product through a manufacturing system. These icons are aided by summary statistics to further detail the specific manufacturing system. The value ...

  20. Effective parameters, effective processes: From porous flow physics to in situ remediation technology

    SciTech Connect

    Pruess, K.

    1995-06-01

    This paper examines the conceptualization of multiphase flow processes on the macroscale, as needed in field applications. It emphasizes that upscaling from the pore-level will in general not only introduce effective parameters but will also give rise to ``effective processes,`` i.e., the emergence of new physical effects that may not have a microscopic counterpart. ``Phase dispersion`` is discussed as an example of an effective process for the migration and remediation of non-aqueous phase liquid (NAPL) contaminants in heterogeneous media. An approximate space-and-time scaling invariance is derived for gravity-driven liquid flow in unsaturated two-dimensional porous media (fractures). Issues for future experimental and theoretical work are identified.

  1. Effects of process parameters in synthesizing Sn nanoparticles via chemical reduction

    NASA Astrophysics Data System (ADS)

    Chee, Sang-Soo; Lee, Jong-Hyun

    2012-02-01

    In order to prepare solder particles for fine pitch interconnections, Sn nanoparticles were synthesized via chemical reduction methods. A number of the process parameters, i.e., injection rate of a precursor solution, application of sonication, reaction temperature, types of reaction medium and capping agent, and drying temperature, are varied in order to study their effect on this process. Using a methanol solution containing 1,10-phenathroline monohydrate, the size of Sn nanoparticles collected after the synthesis decreases as the injection rate increases. An increase in the drying temperature strengthens the degree of agglomeration between Sn nanoparticles, and, in addition, the application of sonication accelerates the process of agglomeration and aggregation between nanoparticles during synthesis. Much smaller Sn nanoparticles are synthesized in diethylene-glycol solutions containing PVP, compared to the methanol solutions with 1,10-phenathroline monohydrate. In the synthesis using diethylene-glycol solutions, the Sn nanoparticle size increases quickly with the reaction temperature.

  2. Neutron coincidence measurements when nuclear parameters vary during the multiplication process

    SciTech Connect

    Lu, Ming-Shih; Teichmann, T.

    1995-07-01

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

  3. Crack toughness evaluation of hot pressed and forged beryllium.

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  4. A Study on Process Parameters of Ultrasonic Assisted Micro EDM Based on Taguchi Method

    NASA Astrophysics Data System (ADS)

    Sundaram, Murali M.; Pavalarajan, Ganesh B.; Rajurkar, Kamlakar P.

    2008-04-01

    Experimental investigation of ultrasonic assisted micro electro discharge machining was performed by introducing ultrasonic vibration to workpiece. The Taguchi experimental design has been applied to investigate the optimal combinations of process parameters to maximize the material removal rate and minimize the tool wear. Analysis of variance (ANOVA) was performed and signal-to-noise (S/N) ratio was determined to know the level of importance of the machining parameters. Based on ANOVA, ultrasonic vibration at 60% of the peak power with capacitance of 3300 PF was found to be significant for best MRR. The machining time plays a significant role in the tool wear. The results were confirmed experimentally at 95% confidence interval.

  5. 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.

  6. Open-die forging of structurally porous sandwich panels

    SciTech Connect

    Elzey, D.M.; Wadley, H.N.G.

    1999-10-01

    Structurally porous metal sandwich panels consisting of dense face sheets and porous cores of controlled relative density can be manufactured by trapping inert gas during hot isostatic pressing and modifying its distribution via subsequent thermomechanical forming. A plane-strain solution for analyzing the open-die forging of such a plastically compressible sandwich panel is developed. An effective yield potential for the face sheet/core sandwich is constructed from the Mises yield criterion for the rigid-plastic face sheet and Doraivelu et al's density-dependent yield function for the compressible core. This effective constitutive response is used in a classical slab analysis of open-die forging. The analysis predicts the upsetting force and the distributions of pressure, core relative density, and average stresses within both the face sheet and the core. During upsetting, a zone of fully constrained material (i.e., with zero lateral strain) is predicted to occur at the center of the workpiece, and this densifies first. A densification front then advances laterally from the panel center toward the outer edges. The nonuniform densification complicates the use of forging for the production of components requiring a uniform density core.

  7. Sinter-forging of nanocrystalline zirconia. 1: Experimental

    SciTech Connect

    Hague, D.C.; Mayo, M.J.

    1997-01-01

    Nanocrystalline (15 nm) yttria (3 mol%)-stabilized zirconia (3Y-TZP) was sinter-forged under conditions of varying temperature (1,050--1,200 C), plastic strain rate (5 {times} 10{sup {minus}5} to 2 {times} 10{sup {minus}3} s{sup {minus}1}), and green density (33--48%), using constant-crosshead-speed tests, constant-load (i.e., load-and-hold) tests, and constant-loading-rate tests. The densification and pore size evolution results indicate that plastic strain is largely responsible for elimination of large pores, while diffusional mechanisms control the elimination of small pores. Grain growth during sinter-forging is observed to be dependent solely on porosity during intermediate-stage sintering. Once the powder compact enters final-stage sintering, however, both static (time- and temperature-dependent) and dynamic (plastic-strain-dependent) grain growth take place, greatly accelerating the overall rate of grain growth. The use of fast strain rates to impose plastic strain before the onset of dynamic grain growth is proposed as a method of preserving small grain sizes during sinter-forging.

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

    SciTech Connect

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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

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

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

    SciTech Connect

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

    2012-01-10

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

  11. Microstructures and Mechanical Properties of Ultrafine Grained Ti-47Al-2Cr (at %) Alloy Produced Using Powder Compact Forging

    NASA Astrophysics Data System (ADS)

    Nadakuduru, Vijay N.; Zhang, Deliang; Cao, Peng; Gabbittas, Brian

    Development of innovative techniques to produce gamma TiAl based alloys, with good mechanical properties, while still maintaining ultra fine grain size can be rewarding, but also is a great challenge. In the present study study a Ti-47Al-2Cr (at %) alloy has been synthesized by directly forging green powder compacts of a Ti/Al/Cr composite powder produced by high energy mechanical milling of a mixture of elemental Ti, Al, Cr powders. It has been found that the density of the bulk consolidated alloy sample after forging decreases from 95% of the theoretical density in the central region to 84% in the periphery region. The microstructure of the bulk alloy consisted of several Ti rich regions, which was expected to be mainly due to initial powder condition. The room temperature tensile strength of the samples produced from this process was found to be in the range of 115 - 130 MPa. The roles of canning and green powder compact density in determining the forged sample porosity level and distribution are discussed.

  12. Effects of Processing Parameters on Massive Production of Graphene by Jet Cavitation.

    PubMed

    Liang, Shuaishuai; Shen, Zhigang; Yi, Min; Liu, Lei; Zhang, Xiaojing; Cai, Chujiang; Ma, Shulin

    2015-04-01

    The massive production of graphene by jet cavitation method with high productivity is demonstrated. Effects of the critical processing parameters on the product dispersions are studied systematically. Experimental results show that high yield of graphene flakes relies on appropriate initial concentration of graphite, high jet pressure, and long treating time. By processing a large batch (10 L) of graphite dispersion for 8 h under 20 MPa in the jet cavitation device, an exfoliation fraction of up to ~12 wt% was achieved. Based on statistical analysis of atomic force microscopy, the as-produced graphene flakes were proved to be highly exfoliated, while the distributions of flake thickness and area became narrower with the increase of treating time. Raman spectra confirm that few defects on the graphene basal planes were induced. In general, the presented approach shows advantages in comparison with peer liquid phase exfoliation methods and thus provides a new route in efficiently producing high-quality graphene in large scale. PMID:26353482

  13. 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

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

    PubMed Central

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

    2013-01-01

    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

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

    SciTech Connect

    Maurel, A.; Fontaine, M.; Thibaud, S.; Michel, G.; Gelin, J. C.

    2007-05-17

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

  16. Optimization of pretreatments and process parameters for sorghum popping in microwave oven using response surface methodology.

    PubMed

    Mishra, Gayatri; Joshi, Dinesh C; Mohapatra, Debabandya

    2015-12-01

    Sorghum is a popular healthy snack food. Popped sorghum was prepared in a domestic microwave oven. A 3 factor 3 level Box and Behneken design was used to optimize the pretreatment conditions. Grains were preconditioned to 12-20 % moisture content by the addition of 0-2 % salt solutions. Oil was applied (0-10 % w/w) to the preconditioned grains. Optimization of the pretreatments was based on popping yield, volume expansion ratio, and sensory score. The optimized condition was found at 16.62 % (wb), 0.55 % salt and 10 % oil with popping yield of 82.228 %, volume expansion ratio of 14.564 and overall acceptability of 8.495. Further, the microwave process parameters were optimized using a 2 factor 3 level design having microwave power density ranging from 9 to 18 W/g and residence time ranging from 100 to 180 s. For the production of superior quality pop sorghum, the optimized microwave process parameters were microwave power density of 18 Wg(-1) and residence time of 140 s. PMID:26604356

  17. Statistical inference methods for recurrent event processes with shape and size parameters

    PubMed Central

    WANG, MEI-CHENG; HUANG, CHIUNG-YU

    2015-01-01

    Summary This paper proposes a unified framework to characterize the rate function of a recurrent event process through shape and size parameters. In contrast to the intensity function, which is the event occurrence rate conditional on the event history, the rate function is the occurrence rate unconditional on the event history, and thus it can be interpreted as a population-averaged count of events in unit time. In this paper, shape and size parameters are introduced and used to characterize the association between the rate function ?(·) and a random variable X. Measures of association between X and ?(·) are defined via shape- and size-based coefficients. Rate-independence of X and ?(·) is studied through tests of shape-independence and size-independence, where the shape-and size-based test statistics can be used separately or in combination. These tests can be applied when X is a covariable possibly correlated with the recurrent event process through ?(·) or, in the one-sample setting, when X is the censoring time at which the observation of N(·) is terminated. The proposed tests are shape- and size-based, so when a null hypothesis is rejected, the test results can serve to distinguish the source of violation. PMID:26412863

  18. Effect of Process Parameters on the Melting Ratio in Overlap Pulsed Laser Welding

    NASA Astrophysics Data System (ADS)

    Sabbaghzadeh, J.; Hamedi, M. J.; Ghaini, F. Malek; Torkamany, M. J.

    2008-04-01

    A study of melting ratio in overlap pulsed laser welding has been done on St14 carbon steel sheet to investigate the effect of process parameters. Pulse duration, pulse energy, pulse frequency, and travel speed were varied in the experimental procedure. The results of the melting ratio have been presented by reforming the related formulas. Formulas have been modified based on overlapping and preheat effect factors. A new parameter is defined to show the actual energy entrance to the spot region in overlapping pulsed laser welding. It is shown that keyhole formation in pulsed laser welding has an essential role in increasing the melting ratio. Moreover, it is shown that the role of pulse energy is more effective on the melting ratio than pulse duration and overlapping process variables. The effect of overlapping has been studied by varying the travel speed and pulse frequency separately, and an optimum range of overlapping for maximizing the melting ratio in the full penetration keyhole mode was established.

  19. Optimization of processing parameters for the preparation of phytosterol microemulsions by the solvent displacement method.

    PubMed

    Leong, Wai Fun; Che Man, Yaakob B; Lai, Oi Ming; Long, Kamariah; Misran, Misni; Tan, Chin Ping

    2009-09-23

    The purpose of this study was to optimize the parameters involved in the production of water-soluble phytosterol microemulsions for use in the food industry. In this study, response surface methodology (RSM) was employed to model and optimize four of the processing parameters, namely, the number of cycles of high-pressure homogenization (1-9 cycles), the pressure used for high-pressure homogenization (100-500 bar), the evaporation temperature (30-70 degrees C), and the concentration ratio of microemulsions (1-5). All responses-particle size (PS), polydispersity index (PDI), and percent ethanol residual (%ER)-were well fit by a reduced cubic model obtained by multiple regression after manual elimination. The coefficient of determination (R(2)) and absolute average deviation (AAD) value for PS, PDI, and %ER were 0.9628 and 0.5398%, 0.9953 and 0.7077%, and 0.9989 and 1.0457%, respectively. The optimized processing parameters were 4.88 (approximately 5) homogenization cycles, homogenization pressure of 400 bar, evaporation temperature of 44.5 degrees C, and concentration ratio of microemulsions of 2.34 cycles (approximately 2 cycles) of high-pressure homogenization. The corresponding responses for the optimized preparation condition were a minimal particle size of 328 nm, minimal polydispersity index of 0.159, and <0.1% of ethanol residual. The chi-square test verified the model, whereby the experimental values of PS, PDI, and %ER agreed with the predicted values at a 0.05 level of significance. PMID:19694442

  20. Development of {gamma}+{alpha}{sub 2}+B2 type titanium aluminide for forged turbine rotors

    SciTech Connect

    Tetsui, Toshimitsu

    1995-12-31

    In order to apply TiAl for forged turbine rotors, hot deformability at manufacturing process and high temperature strength at application are both required. For these requirements a new {gamma}+{alpha}{sub 2}+B2 type TiAl (named KAT-3) has been developed. The alloy composition is Ti-45Al-8Nb-2Cr (at%) and this alloy consists of three phases: {gamma}, {alpha}{sub 2} and B2. Because B2 phase has excellent hot deformability and {gamma}/{alpha}{sub 2} lamellar structure has excellent high temperature strength, the above contradictory requirements for TiAl can both be achieved by optimizing the manufacturing process. In this paper various properties required for turbine rotor materials of this alloy were investigated, especially in comparison with Inconel 713C.

  1. Solventless visible light-curable coating: I. Critical formulation and processing parameters.

    PubMed

    Bose, Sagarika; Bogner, Robin H

    2010-06-30

    Film coating is generally accomplished by spraying polymers dissolved in solvents onto a cascading bed of tablets. The limitations associated with the use of solvents (both aqueous and organic) can be overcome by the use of solventless coating technologies. In this proposed solventless photocurable film coating system, each layer of coating onto the pellets (non-pareil beads) was formed using liquid photocurable monomer, powdered pore-forming agents, photosensitizers and photoinitiators in a mini-coating pan and later cured by visible light. Yield, coating efficiency, variation in color, diameter and roundness were determined for each batch to evaluate process efficiency and coating quality. It was found that the ratio (S/L ratio) of the amount of solid (S) pore-forming agent to volume of liquid (L) monomer, particle size and type of the pore-forming agent, concentration of initiator, and total exposure (light intensity x exposure time) of light were critical formulation and processing parameters for the process. Using lactose as a pore-forming agent, an optimum ratio of pore-forming agent to photocurable polymer was 1.8-3.0 to achieve good process efficiency and uniformity. The ratio was sensitive to particle size and type of pore-forming agent. PMID:20138131

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

    NASA Astrophysics Data System (ADS)

    Webster, Donald; Kirkbride, Richard

    1986-11-01

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

  3. 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.

  4. Evolving chemometric models for predicting dynamic process parameters in viscose production.

    PubMed

    Cernuda, Carlos; Lughofer, Edwin; Suppan, Lisbeth; Röder, Thomas; Schmuck, Roman; Hintenaus, Peter; Märzinger, Wolfgang; Kasberger, Jürgen

    2012-05-01

    In viscose production, it is important to monitor three process parameters in order to assure a high quality of the final product: the concentrations of H(2)SO(4), Na(2)SO(4) and Z(n)SO(4). During on-line production these process parameters usually show a quite high dynamics depending on the fiber type that is produced. Thus, conventional chemometric models, which are trained based on collected calibration spectra from Fourier transform near infrared (FT-NIR) measurements and kept fixed during the whole life-time of the on-line process, show a quite imprecise and unreliable behavior when predicting the concentrations of new on-line data. In this paper, we are demonstrating evolving chemometric models which are able to adapt automatically to varying process dynamics by updating their inner structures and parameters in a single-pass incremental manner. These models exploit the Takagi-Sugeno fuzzy model architecture, being able to model flexibly different degrees of non-linearities implicitly contained in the mapping between near infrared spectra (NIR) and reference values. Updating the inner structures is achieved by moving the position of already existing local regions and by evolving (increasing non-linearity) or merging (decreasing non-linearity) new local linear predictors on demand, which are guided by distance-based and similarity criteria. Gradual forgetting mechanisms may be integrated in order to out-date older learned relations and to account for more flexibility of the models. The results show that our approach is able to overcome the huge prediction errors produced by various state-of-the-art chemometric models. It achieves a high correlation between observed and predicted target values in the range of [0.95,0.98] over a 3 months period while keeping the relative error below the reference error value of 3%. In contrast, the off-line techniques achieved correlations below 0.5, ten times higher error rates and the more deteriorate, the more time passes by. PMID:22502608

  5. 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.

  6. 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

  7. Detecting documents forged by printing and copying

    NASA Astrophysics Data System (ADS)

    Shang, Shize; Memon, Nasir; Kong, Xiangwei

    2014-12-01

    This paper describes a method to distinguish documents produced by laser printers, inkjet printers, and electrostatic copiers, three commonly used document creation devices. The proposed approach can distinguish between documents produced by these sources based on features extracted from the characters in the documents. Hence, it can also be used to detect tampered documents produced by a mixture of these sources. We analyze the characteristics associated with laser/inkjet printers and electrostatic copiers and determine the signatures created by the different physical and technical processes involved in each type of printing. Based on the analysis of these signatures, we computed the features of noise energy, contour roughness, and average gradient. To the best of our knowledge, this is the first work to distinguish documents produced by laser printer, inkjet printer, and copier based on features extracted from individual characters in the documents. Experimental results show that this method has an average accuracy of 90% and works with JPEG compression.

  8. The effect of selected parameters of the honing process on cylinder liner surface topography

    NASA Astrophysics Data System (ADS)

    Pawlus, P.; Dzierwa, A.; Michalski, J.; Reizer, R.; Wieczorowski, M.; Majchrowski, R.

    2014-04-01

    Many truck cylinder liners made from gray cast iron were machined. Ceramic and diamond honing stones were used in the last stages of operation: coarse honing and plateau honing. The effect of honing parameters on the cylinder liner surface topography was studied. Selected surface topography parameters were response variables. It was found that parameters from the Sq group were sensitive to honing parameter change. When plateau honing time varied, the Smq parameter increased, while the other parameters, Spq and Svq, were stable.

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

    NASA Astrophysics Data System (ADS)

    Schorderet, Alain; Deghilage, Emmanuel; Agbeviade, Kossi

    2011-05-01

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

  10. 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.

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

    SciTech Connect

    Abushgair, K.

    2015-03-30

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  13. The Parameter Identification of Thermal Visco-plastic Model Considering Dynamic Recrystallization

    NASA Astrophysics Data System (ADS)

    Jin, Quanlin; Qu, Jie; Xu, Bingye

    2004-06-01

    A study on parameter identification of thermal visco-plastic model considering dynamic recrystallization is presented in this paper. A hybrid global optimization method is constructed and applied in the parameter identification. The hybrid global optimization method is a combination of the Real-coded genetic algorithm (RGA) and some classical local search methods (such as Levenberg-Marquardt method, augmented Gauss-Newton algorithm and the flexible tolerance method) in order to accommodate the characters of the objective function used for parameter identification of the thermal visco-plastic model considering dynamic recrystallization. A special numerical procedure of the parameter identification is also made through cooperation of the hybrid global optimization and a thermal rigid-plastic FEM for simulation of hot forging process. Finally, as numerical example, a set of satisfactory material parameters for 26Cr2Ni4MoV steel is presented by the numerical procedure.

  14. Functional relationships for the estimation of van Genuchten parameter values in landfill processes models.

    PubMed

    White, Jim; Zardava, Kiriaki; Nayagum, Dharumarajen; Powrie, William

    2015-04-01

    Numerical models of landfill processes need to be able to estimate the capillary pressure and relative permeability of waste as a function of moisture content using analytical equations such as the van Genuchten equations. The paper identifies the range of van Genuchten parameter values for use in models and proposes a formulaic relationship between these parameter values and saturated moisture content. The concept of porous material, its behaviour under unsaturated conditions and Mualem's integral transform equation that estimates relative permeability from capillary pressure are reviewed. The application of the algebraic form of the capillary pressure function proposed by van Genuchten and its application using Mualem's transform to obtain the van Genuchten algebraic functions for relative permeability are discussed. Functional relationships are identified between saturated moisture content and the van Genuchten parameters using a database of results from other sources. These relationships may be used in numerical modelling of unsaturated flow in landfilled waste where the saturated moisture content varies significantly as the result of compression, settlement and degradation. A 2D numerical model simulation of leachate recirculation is used to investigate the sensitivity of the simulation to the introduction of these functional relationships. It is found that the transient liquid and gas flows across the model boundaries appear to be insensitive to whether or not the functions are incorporated into the model algorithm. However it is observed that using the relationships does have some impact on the distribution of the degree of saturation throughout the model and on the transient behaviour of the way in which the recirculation recharges the waste. However it is not thought that this impact would be sufficient to influence the design of a leachate recirculation system. PMID:25573738

  15. High temperature mechanical properties of Ti-47Al-2Cr (at %) alloy produced using powder compact forging of a mechanically milled powder

    NASA Astrophysics Data System (ADS)

    Nadakuduru, V. N.; Zhang, D. L.; Cao, P.; Gabbitas, B.

    2009-08-01

    Ultrafine grained (UFG) Ti-47Al-2Cr (at %) alloy was prepared using a combination of high energy ball milling of a mixture of elemental powders to produce a Ti/Al/Cr composite powder and forging of compacts of this composite powder. The microstucture of the powder forged alloy was found to be dependent on the initial condition of the powder. The alloy produced by this method has demonstrated good formability, both in tensile and compression testings at elevated temperatures. A ductility of 80-165% in tension has been observed, while in a compression plastic strain of ~ 50% was found to be easily achievable, without causing cracking. The deformation behaviour of the particular alloy in tension and compression at elevated temperature has been discussed in detail. The results from the present investigation indicate that UFG Ti-47Al-2Cr (at %) alloy produced using powder compact forging has good formability, and is suitable precursor for near-net shaping using thermomechanical processes such as forging and superplastic forming.

  16. Investigation of environmental physical parameters and processes complementing the search for signatures of life

    NASA Astrophysics Data System (ADS)

    Richter, L.; Horneck, G.; Kochan, H.; Rabbow, E.; Rettberg, P.; Ulamec, S.

    In general, the search for signatures of life on other planets follows different lines: one is to study life in extreme natural environments on the Earth, another one is to perform laboratory experiments under simulated natural conditions in order define the limits for formation and survival of life, and finally space missions to perform in situ measurements on planetary surfaces outside the Earth to look for indicators of extinct or extant life. For the case of the planet Mars, relevant surface conditions are roughly known from orbiter as well as lander missions. In an extrapolation of terrestrial conditions, laboratory studies are conducted on terrestrial biota from extreme environments under various simulated planetary surface conditions in order to investigate general biological survivability as a function of physical and chemical parameters (radiation, UV flux, atmosphere, temperature, humidity, soil properties including mineralogy and toxicity, etc.). This way, physical parameters and processes acting on planetary bodies and their interrelations are studied in parallel with the search for surviving biota. Several suitable test chambers for physical and for biological investigations of this type are available at DLR Cologne. Ultimately, the same physical quantities should be measured concurrently with biological measurements during future planetary landing missions searching for signatures of life. The general question, however, remains whether life on Earth shows any biochemical resemblance with hypothetical life on ancient or modern Mars.

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

    SciTech Connect

    Katsobashvili, Y.R.

    1982-11-06

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

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

    NASA Astrophysics Data System (ADS)

    Sharma, S.

    2013-10-01

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

  19. 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.

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

    PubMed

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

    2014-12-01

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

  1. HESS Opinions: Advocating process modeling and de-emphasizing parameter estimation

    NASA Astrophysics Data System (ADS)

    Bahremand, A.

    2015-11-01

    Since the origins of hydrology as an engineering discipline, where "black box" modelling approaches were common, it has evolved into a scientific discipline that seeks a more "white box" modelling approach to solving problems such as description and simulation of the rainfall-runoff responses of a watershed. There has been much recent debate regarding the future of the hydrological sciences, and several publications have voiced opinions on this subject. This opinion paper seeks to comment and expand on some recent publications that have advocated an increased focus on process modelling while de-emphasizing the focus on detailed attention to parameter estimation. In particular, it offers a perspective that emphasizes a more hydraulic (more physics and less conceptual) approach to development and implementation of hydrological models.

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

    SciTech Connect

    Castro, R.G.; Stanek, P.W.; Jacobson, L.A.; Cowgill, D.F.; Snead, L.L.

    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.

  3. 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.

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

    SciTech Connect

    Wagner, Sara E.; Burch, James B.; South Carolina Statewide Cancer Prevention and Control Program, Columbia, SC; WJB Dorn Veteran's Affairs Medical Center, Columbia, SC ; Bottai, Matteo; Pinney, Susan M.; Puett, Robin; South Carolina Statewide Cancer Prevention and Control Program, Columbia, SC; Arnold School of Public Health, Department of Environmental Health Sciences, University of South Carolina, Columbia, SC ; Porter, Dwayne; Vena, John E.; Hebert, James R.; South Carolina Statewide Cancer Prevention and Control Program, Columbia, SC

    2010-11-15

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

  5. 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.

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

    PubMed Central

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

    2015-01-01

    Welding fumes (WF) are a complex mixture of toxic metals and gases, inhalation of which can lead to adverse health effects among welders. The presence of manganese (Mn) in welding electrodes is cause for concern about the potential development of Parkinson’s disease (PD)-like neurological disorder. Consequently, from an occupational safety perspective, there is a critical need to prevent adverse exposures to WF. As the fume generation rate and physicochemical characteristics of welding aerosols are influenced by welding process parameters like voltage, current or shielding gas, we sought to determine if changing such parameters can alter the fume profile and consequently its neurotoxic potential. Specifically, we evaluated the influence of voltage on fume composition and neurotoxic outcome. Rats were exposed by whole-body inhalation (40 mg/m3; 3 h/day × 5 d/week × 2 weeks) to fumes generated by gas–metal arc welding using stainless steel electrodes (GMA-SS) at standard/regular voltage (25 V; RVSS) or high voltage (30 V; HVSS). Fumes generated under these conditions exhibited similar particulate morphology, appearing as chain-like aggregates; however, HVSS fumes comprised of a larger fraction of ultrafine particulates that are generally considered to be more toxic than their ne counterparts. Paradoxically, exposure to HVSS fumes did not elicit dopaminergic neurotoxicity, as monitored by the expression of dopaminergic and PD-related markers. We show that the lack of neurotoxicity is due to reduced solubility of Mn in HVSS fumes. Our findings show promise for process control procedures in developing prevention strategies for Mn-related neurotoxicity during welding; however, it warrants additional investigations to determine if such modifications can be suitably adapted at the workplace to avert or reduce adverse neurological risks. PMID:25549921

  7. Trial production of large high-quality forging ingots

    SciTech Connect

    Sigachev, A.A.; Davidenko, N.I.; Betin, G.Ya.; Pliskanovskii, A.S.; Kononets, A.I.; Revtov, N.I.

    1988-03-01

    The Azovstal' combine studied methods to improve the quality of its large forging ingots. Steel 10KhSND was made in a 350-ton oxygen converter and the mold walls were lined with chrome-magnesite, high-alumina, or fireclay. Nonmetallic inclusions of the trial steel were found to include sulfides, oxides, titanium nitrides, silicates, and aluminosilicates. Usable output increased due to an improvement in the quality of the ingots with a 20-25% reduction in crop and in material and energy costs.

  8. Sinter-forging characteristics of fine-grained zirconia

    SciTech Connect

    Panda, P.C.; Wang, J.; Raj, R.

    1988-12-01

    Powder preforms of zirconia, containing 2.85 mol% yttria, were sinter-forged in simple uniaxial compression at 1400/sup 0/C by applying constant displacement rates to the specimens. Shear and densification strains and the uniaxial stress were measured as a function of time. In contrast with alumina and silicon nitride, zirconia appears to densify by a dislocation mechanism. As a consequence, the densification rate is linked to the applied strain rather than to the applied hydrostatic pressure: the powder compact requires a critical amount of compressive strain to consolidate to full density, irrespective of the strain rate or the stress at which that strain is applied.

  9. Relationship among synthesis, microstructure and properties in sinter-forged Bi-2212 ceramics

    NASA Astrophysics Data System (ADS)

    Garnier, V.; Caillard, R.; Sotelo, A.; Desgardin, G.

    1999-06-01

    High quality Bi-2212 powders were prepared using three different synthetic methods (solid state, sol-gel and polymer matrix), showing that the polymer matrix method is very promising from the point of view of the synthesis time and grain size. The Bi-2212 sintered pellets were then submitted to sinter-forging process to obtain textured ceramic discs. The discs were characterized by XRD, pole figures and SEM to determine the phase purity, the texture degree and the microstructure, respectively. Following characterization, the discs were cut into bars and annealed for 12 h at different temperatures ranging between 845 and 873°C to determine the best thermal treatment, whereafter they were characterized using resistivity and transport Jc measurements. It has been found that most of the bars had a Tc around 92 K and that transport properties can be correlated to the samples' microstructure.

  10. Grain-Boundary Parameters Controlled Allotriomorphic Phase Transformations in Beta-Processed Titanium Alloys

    NASA Astrophysics Data System (ADS)

    Dixit, Vikas

    Allotriomorphic or grain-boundary alpha (GBalpha) is an unavoidable and important microstructural feature of the diffusional phase transformations in beta-processed titanium alloys. This phase has a negative influence on various mechanical properties, such as high cycle fatigue, fracture toughness, ductility etc. and has a profound influence on the overall microstructural evolution. In the present work, the evolution of GBalpha has been in explored relative to the grain-boundary parameters namely, misorientation angle and axis, and the GB plane. While the misorientation angle and axis relate to the crystallography of adjacent crystals and can easily be determined using diffraction based techniques, an accurate determination of the local crystallographic orientation of the GB plane is difficult because of its three-dimensional nature. To address this issue, two independent experimental approaches have been developed and validated by utilizing a combination of dual beam focused ion beam (FIB), SEM and electron back-scattered diffraction (EBSD) methods. Both these approaches considerably simplify the problem because of a relatively easier experimental set-up and a versatile methodology. The crystallographic variant selection and morphology of GBalpha have been subsequently evaluated relative to the quantified GB parameters. Results indicate that in alpha/beta- and beta-titanium alloys, the crystallographic variant selection and GB parameters control the evolution of the allotriomorphic alpha phase. In particular, misorientation angle/ axis parameters control the early precipitation of GBalpha. The grain-boundaries of those adjacent beta-grains that produce nearly parallel and/or poles are the preferred sites for the early nucleation of GBalpha. In addition, these closely related poles significantly influence the crystallographic variant selection criterion in a majority of cases and contribute to a considerable short-listing of the allowed variants of GBalpha. The morphology of GBalpha is primarily controlled by the inclination of the GB plane relative to the selected crystallographic variant of the Burgers-OR at grain-boundaries. In beta-titanium alloys, continuous GBalpha precipitates are produced when the GB plane orients nearly perpendicular to the invariant line of the contributing Burgers-OR. In case of alpha/beta-titanium alloys, the thickening of GBalpha is higher when the GB plane orients close to the broad-face or the habit plane of the Burgers-OR. It has been proposed for the first time that the crystallographic and morphological aspects of GBalpha and adjacent Widmanstatten alpha are interrelated and primarily dictated by the GB parameters. Specifically, once a particular crystallographic variant of GBalpha is chosen by a set of criterion, the crystallographic and morphological nature of adjacent Widmanstatten alpha is also predicted. The resulting Widmanstatten alpha morphology in combination with the nature of the GB parameters would control the growth (continuous or discrete) of GBalpha. Finally, transmission electron microscopy studies have revealed a variation in the interfacial structure between GBalpha and the adjacent beta grain, different from previously known well-defined interfacial structure between Widmanstatten alpha and the parent beta phase. The faceting of the interface as well as presence of new sets of misfit dislocations have been observed in this work.

  11. 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

  12. Parameter study of r-process lanthanide production and heating rates in kilonovae

    NASA Astrophysics Data System (ADS)

    Lippuner, Jonas; Roberts, Luke F.

    2015-04-01

    Explosive r-process nucleosynthesis in material ejected during compact object mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients are sensitive to the composition of the material after nuclear burning ceases, as the composition determines the local heating rate from nuclear decays and the opacity. The presence of lanthanides in the ejecta can drastically increase the opacity. We use the new general-purpose nuclear reaction network SkyNet to run a parameter study of r-process nucleosynthesis for a range of initial electron fractions Ye, initial entropies s, and density decay timescales ?. We find that the ejecta is lanthanide-free for Ye >~ 0 . 22 - 0 . 3 , depending on s and ?. The heating rate is insensitive to s and ?, but certain, larger values of Ye lead to reduced heating rates, because single nuclides dominate the heating. With a simple model we estimate the luminosity, time, and effective temperature at the peak of the light curve. Since the opacity is much lower in the lanthanide-free case, we find the luminosity peaks much earlier at ~ 1 day vs. ~ 15 days in the lanthanide-rich cases. Although there is significant variation in the heating rate with Ye, changes in the heating rate do not mitigate the effect of the lanthanides. This research is partially supported by NSF under Award Numbers AST-1333520 and AST-1205732.

  13. 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.

  14. 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.

  15. 77 FR 14445 - Application for a License To Export Steel Forging

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ... Spain. December 15, 2011 head steel head steel February 7, 2012 forging. forging will be XR175 machined... FR 49139 (Aug. 28, 2007). Information about filing electronically is available on the NRC's public... least 5 (five) days prior to the filing deadline, the petitioner/requestor should contact the Office...

  16. 75 FR 67110 - Forged Stainless Steel Flanges From India and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-01

    ... employees, and Commission rule 201.15(b)(19 CFR 201.15(b)), 73 FR 24609 (May 5, 2008). This advice was... imports of forged stainless steel flanges from India and Taiwan (59 FR 5994). Following first five-year... antidumping duty orders on imports of forged stainless steel flanges from India and Taiwan (65 FR...

  17. 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

    ... Order No. 5-2010 (72 FR 55355). Signed at Washington, DC, on May 19, 2011. David Michaels, Assistant... Occupational Safety and Health Administration Forging Machines; Extension of the Office of Management and... contained in the Forging Machines Standard (29 CFR 1910.218). The paperwork provisions of the...

  18. 76 FR 8773 - Forged Stainless Steel Flanges From India and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ..., * * *'' (76 FR 5331). Accordingly, pursuant to section 751(c) of the Tariff Act of 1930 (19 U.S.C. 1675(c... Forged Stainless Steel Flanges From India and Taiwan AGENCY: United States International Trade Commission... November 2010 to determine whether revocation of the antidumping duty orders on forged stainless...

  19. 75 FR 70689 - Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum-Greenwood Forge Division; Currently...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-18

    ... in the Federal Register on November 17, 2009 (74 FR 59254). At the request of the State agency and a... and Training Administration Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum- Greenwood Forge... Aluminum Fabricated Products, LLC, Kaiser Aluminum-Greenwood Forge Division, including on- site...

  20. Mechanical Behavior of Cryomilled CP-Ti Consolidated via Quasi-Isostatic Forging

    NASA Astrophysics Data System (ADS)

    Ertorer, Osman; Zúñiga, Alejandro; Topping, Troy; Moss, Wes; Lavernia, Enrique J.

    2009-01-01

    Commercially pure (CP) Ti (Grade 2 with chemical composition 0.190 wt pct O, 0.0165 wt pct N, 0.0030 wt pct C, and 0.013 wt pct Fe) was cryomilled in liquid argon and liquid nitrogen for 8 hours. The influence of the milling environment on the chemistry, grain size, and grain-boundary structure of CP-Ti was studied by means of transmission electron microscopy (TEM), X-ray diffraction (XRD), and chemical analysis. The results show that the final average grain size obtained after 8 hours of cryomilling was ˜20 nm, for both liquid nitrogen and liquid argon cryomilling environments. Grains were observed to be heavily deformed and they did not reveal well-defined boundaries between them. Liquid nitrogen and liquid argon cryomilling environments led to differences in the final powder chemistry. Cryomilling in liquid nitrogen resulted in Ti powders with ˜2 wt pct nitrogen, which caused embrittlement that in turn affected the mechanical behavior of the consolidated materials. Cryomilling in liquid argon resulted in powders with slightly higher oxygen levels than those from liquid nitrogen experiments; this was attributed to the use of stearic acid (CH3(CH2)16COOH) as a process control agent (PCA). The cryomilled powders, in the form of various compositional blends from the argon and nitrogen milling experiments, were subsequently consolidated via quasi-isostatic (QI) forging, for mechanical behavior studies. The mechanical testing results showed that the QI-forged 85 pct as-received +15 pct liquid-argon-cryomilled powder blend exhibited ˜30 pct elongation to fracture, with a yield strength (YS) of 601 MPa and an ultimate tensile strength (UTS) of 711 MPa. In the case of 100 pct liquid-argon-cryomilled and QI-forged material, the YS, UTS, and elongation values were 947 and 995 MPa and 4.32 pct, respectively. The mechanical behavior was discussed in terms of the operative microstructure mechanisms. The enhanced ductility noted in the blended powders was discussed in terms of the presence of a bimodal microstructure.

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

    NASA Astrophysics Data System (ADS)

    Polowick, Christopher

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

  2. Multiple Processes and Multiple Parameters: Applications of In Situ UV Spectroscopy for Aquatic Ecosystems

    NASA Astrophysics Data System (ADS)

    Cohen, M. J.; Hensley, R. T.; Reijo, C. J.; Heffernan, J. B.; Thomas, R. G.; Korhnak, L. V.

    2012-12-01

    Modern sensors afford new temporal and spatial scales of environmental measurements, providing novel insights into processes that govern earth surface and ecosystem dynamics. Recent advances from deploying in situ sensors include inference of reach-scale stoichiometric coupling (C:N:P) of whole-ecosystem metabolism, finely detailed resolution of the behavior of multiple solutes during storm events and snow-melt, and spatial and process disaggregation of nitrogen removal in rivers. These particular process inferences are predicated on in situ UV spectrometers that, to date, have been used principally to provide high quality temporally-dense measurements of nitrate. Here we focus on additional inferences, still largely exploratory, of ecosystem processes that are made possible in parallel with these same sensors. We focus on UV sensors capable of measuring absorbance from the entire UV spectrum at relatively high spectral resolution (ca. 1 nm), and we discuss three new applications. First, we explore the use of UV spectra for inferring information about the quality and quantity of dissolved organic matter. Diel and event driven variation in wavelength-specific absorbance and metrics like spectral slope in the 350-400 nm range (an indicator of aromaticity) illustrate that important inferences relevant to riverine organic matter cycling can be obtained during passive deployments. Second, we present preliminary data to support the use of these sensors for injected solute experiments. Since both nitrate and bromide absorb in the deep UV, these sensors can be used to estimate concentrations of both during co-injection dosing. We present protocols and data from two such deployments, one in a lotic system and another in a wetland where we use high-resolution time series of measured concentrations to draw inference about N retention kinetics. Finally, we present new data from two-station deployments to obtain spatially compact reach scale measurements of N retention, focusing on the coupled effects of diel and tidal variation on removal rates. The potential to extract, in parallel, multiple parameters and draw inference about multiple processes, illustrates the promise of optical sensors, which are but one axis of recent sensor advances.

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

    SciTech Connect

    Schorderet, Alain; Deghilage, Emmanuel; Agbeviade, Kossi

    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.

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

    SciTech Connect

    Petrov, A.; Petrov, P.; Petrov, M.

    2011-05-04

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

  5. Effect of operating parameters on the removal of bone cement by a sawing process.

    PubMed

    James, Thomas P; Sheehan, Brian; Sagar, Amrit

    2014-03-01

    The number of total knee arthroplasty revision surgeries is increasing each year, driven by the wide availability and general acceptance of the procedure accompanied by an aging population of implants. Metal implants are often secured to the tibial plateau by a mantle of poly(methyl methacrylate) bone cement. During revision surgery, a power oscillating saw is used to remove bone cement while preparing the boney bed. Presently, there are no published studies on the mechanics of bone cement removal by a sawing process. The aim of this research was to quantify the effect of blade speed and applied thrust force on the volumetric cutting rate of bone cement. A custom reciprocating saw with variable stroke length was used to conduct a three-factor design of experiments. Two levels, without center-points, were sufficient to model the effect of stroke length (6.75, 10.13 mm), thrust force (11, 19 N), and reciprocating speed in strokes per minute (6000, 8000 SPM) on cutting rate. The results indicate that each of the three parameters had a significant impact on cutting rate (p < 0.001), with a linear relationship between both force and cutting rate (r = 0.98) and blade speed and cutting rate (r = 0.98). For the parameters considered, increasing the reciprocating speed had the most significant effect on cutting rate. For example, while holding force and stroke length constant (11 N, 10.13 mm), an increase in speed from 6000 to 8000 SPM nearly doubled the cutting rate of bone cement. A cutting rate model was developed by regression analysis of the experimental data and validated through additional experiments. The model has applications in haptic feedback for surgical simulators to differentiate between the cutting rates of bone and bone cement during virtual training of resident surgeons. PMID:24562099

  6. 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...Antidumping Duty Orders on Heavy Forged Hand Tools From China. AGENCY: United States...antidumping duty orders on heavy forged hand tools from China would be likely to...

  7. 77 FR 39997 - Heavy Forged Hand Tools, Finished or Unfinished, With or Without Handles From the People's...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-06

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

  8. 76 FR 5331 - Forged Stainless Steel Flanges From India and Taiwan: Final Results of Sunset Reviews and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-31

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

  9. 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

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

    SciTech Connect

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

    2011-06-23

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

  11. 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.

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

    PubMed

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

    2009-08-01

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

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. Effect of process design and operating parameters on aerobic methane oxidation in municipal WWTPs.

    PubMed

    Daelman, Matthijs R J; Van Eynde, Tamara; van Loosdrecht, Mark C M; Volcke, Eveline I P

    2014-12-01

    Methane is a potent greenhouse gas and its emission from municipal wastewater treatment plants (WWTPs) should be prevented. One way to do this is to promote the biological conversion of dissolved methane over stripping in aeration tanks. In this study, the well-established Activated Sludge Model n°1 (ASM1) and Benchmark Simulation Model n°1 (BSM1) were extended to study the influence of process design and operating parameters on biological methane oxidation. The aeration function used in BSM 1 was upgraded to more accurately describe gas-liquid transfer of oxygen and methane in aeration tanks equipped with subsurface aeration. Dissolved methane could be effectively removed in an aeration tank at an aeration rate that is in agreement with optimal effluent quality. Subsurface bubble aeration proved to be better than surface aeration, while a CSTR configuration was superior to plug flow conditions in avoiding methane emissions. The conversion of methane in the activated sludge tank benefits from higher methane concentrations in the WWTP's influent. Finally, if an activated sludge tank is aerated with methane containing off-gas, a limited amount of methane is absorbed and converted in the mixed liquor. This knowledge helps to stimulate the methane oxidizing capacity of activated sludge in order to abate methane emissions from wastewater treatment to the atmosphere. PMID:25225767

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

    PubMed

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

    2008-05-01

    Statistically based experimental designs were applied to optimizing process parameters for hydrogen production from glucose by Clostridium sp. Fanp2 which was isolated from effluent sludge of anaerobic hydrogen-producing bioreactor. The important factors influencing hydrogen production, which identified by initial screening method of Plackett-Burman, were glucose, phosphate buffer and vitamin solution. The path of steepest ascent was undertaken to approach the optimal region of the three significant factors. Box-Behnken design and response surface analysis were adopted to further investigate the mutual interaction between the variables and identify optimal values that bring maximum hydrogen production. Experimental results showed that glucose, vitamin solution and phosphate buffer concentration all had an individual significant influence on the specific hydrogen production potential (Ps). Simultaneously, glucose and vitamin solution, glucose and phosphate buffer were interdependent. The optimal conditions for the maximal Ps were: glucose 23.75 g/l, phosphate buffer 0.159 M and vitamin solution 13.3 ml/l. Using this statistical optimization method, the hydrogen production from glucose was increased from 2248.5 to 4165.9 ml H2/l. PMID:17644378

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

    PubMed

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

    2010-04-01

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

  20. Crack toughness evaluation of hot pressed and forged beryllium

    NASA Technical Reports Server (NTRS)

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

    1971-01-01

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

  1. Research on a New Process of the Non-quenched and Tempered Steel with High Strength and High Toughness

    NASA Astrophysics Data System (ADS)

    Bo, Zhou; Yong, Shen; Li, TAN; Hong-Xin, YANG; Wen-Quan, CAO; Yao-Zong, BAO

    The controlled-forging and controlled-cooling has become the main process of the non-quenched and tempered steels now. However, there is a problem that the unstable toughness and its lower values restrict the expanded application and the development of the steels. In this study, the process of the non-quenched and tempered steels was optimized through the micro- alloying and the controlled-forging and controlled-cooling technology. The simulated rapid cooling followed by self tempering after forging was tried to control the microstructure and mechanical properties of the steels. A new process of the non-quenched and tempered steels was proposed to ensure high strength and high toughness for the studied steels. The toughening and strengthening mechanism of the steels processed by the new process was discussed and evaluated, which could provide the fundamental theory, technical support and process parameters for the industrialized production of the high strength and high toughness non-quenched and tempered steels.

  2. Energy and exergy analysis of a chemical process system with distributed parameters based on the enthalpy-direction factor diagram

    SciTech Connect

    Masaru, I.; Katsuhlto, K.

    1982-10-01

    The enthalpy-direction factor diagram is proposed for energy and exergy analysis of chemical process systems. Focusing on the exchange of energy between the energy-donating processes and the energy-accepting ones, this diagram makes it possible to analyze systematically the effect of the distributed parameters of the process. Various kinds of exergy annihilation caused by heat exchange, reaction, and so forth are obtained as the area on it. It is compared to the structured energy-exergy flow diagram (SPEED). The latter focusses on the transformation of exergy among the processes and is developed to analyze hierarchical structure of the process system on the lumped-parameter basis. It is shown that the latter diagram is appropriate for exergy integration tasks to compose the skeleton of the hierarchical system structure and the former is suitable for energy integratio tasks to polish it up.

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

    PubMed

    Milatou, Niki; Dassenakis, Manos; Megalofonou, Persefoni

    2015-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

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

    PubMed Central

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

    2013-01-01

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

  6. 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.

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

    NASA Technical Reports Server (NTRS)

    Brennecke, M. W.

    1978-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

  10. 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.

  11. 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.

  12. 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.

  13. The digital array at Anza, California: Processing and initial interpretation of source parameters

    NASA Astrophysics Data System (ADS)

    Fletcher, Jon; Haar, Linda; Hanks, Thomas; Baker, Lawrence; Vernon, Frank; Berger, Jon; Brune, James

    1987-01-01

    Seismicity along the San Jacinto fault suggests that a 40-km-long section near the town of Anza may constitute a gap in the occurrence of ML = 6-7 earthquakes. The potential for a gap-filling shock and the high rate of seismicity at the southern end of the gap (five events of 4.0 ? ML ? 5.5 since 1970) provided the impetus for deploying a digital seismic array to collect high-quality ground motion recordings of all events 2 ? ML ? 4.5 (on-scale recording for shocks with magnitudes above ML = 4 can be obtained from an existing array of eight strong motion accelerographs). The Anza site also had the advantage of being in the southern California batholith, which appears to be relatively homogeneous compared to the Franciscan/Gablian contrast of the central San Andreas; we expected that the granitic rocks of the batholith would yield relatively accurate earthquake locations and efficiently propagate high frequencies. The field instrumentation is specifically designed for broadband recording (up to 70 Hz) and high dynamic range (96 dB in the on-site digitizer alone), since both are necessary for determining the rupture history of earthquakes. Both local VHF and microwave digital telemetry transmit the data from the Anza region to San Diego for computer data logging. In the first 30 months of the array's operation, approximately 292 events have been recorded, located, and processed for source parameters. Most events occur in one of five clusters or in a diffuse zone near the Buck Ridge fault. Two of these clusters are located at right-stepping en echelon offsets (Coyote Creek-San Jacinto and San Jacinto-Hot Springs); two others are directly below and about 8 km west of Anza, respectively. The fifth cluster is just to the northeast of the Hot Springs fault. Although event depths are generally between 11 and 14 km, at the southern end of the Hot Springs fault, depths extend to 18 km; these are some of the deepest strike-slip earthquakes on the San Andreas system. We calculate source parameters such as the scalar moment and stress drop for the analysis of high-frequency waves, scaling relations, and earthquake interaction. The largest event recorded thus far had a moment of 4.4 × 1021 dyn cm (M = 3.8) and a stress drop of 55 bars. Both arms and Brune stress drops increase with moment; source radius increases only slowly with moment. The maximum values of both the Brune and arms stress drops increase with depth down to 10 km, remain approximately constant to 14 km, and may decrease below 14 km. The data suggest that stress drops of a group of earthquakes can be related to the strength of the upper crust calculated from frictional and quasi-plastic flow laws, although individual events may not be related. Stress drops on the San Jacinto fault are high compared to those on the central creeping section of the San Andreas, where stress drops are about 10 bars or less. This observation is consistent with the relative rupture area of events of equal ML (5.5) and may be related to the lithologie differences between the two fault segments and the amount of normal stress compared to shear stress.

  14. Tradeoffs in Data Acquisition and Processing Parameters for Backscatter and Scatterer Size Estimations

    PubMed Central

    Liu, Wu; Zagzebski, James A.

    2010-01-01

    By analyzing backscattered echo signal power spectra and thereby obtaining backscatter coefficient vs. frequency data, the size of sub-resolution scatterers contributing to echo signals can be estimated. Here we investigate tradeoffs in data acquisition and processing parameters for reference phantom based backscatter and scatterer size estimations. RF echo data from a tissue-mimicking test phantom were acquired using a clinical scanner equipped with linear array transducers. One array has a nominal frequency bandwidth of 5–13 MHz and the other 4–9 MHz. Comparison of spectral estimation methods showed that the Welch method provided spectra yielding more accurate and precise backscatter coefficient and scatterer size estimations than spectra computed by applying rectangular, Hanning, or Hamming windows and much reduced computational load than if using the multitaper method. For small echo signal data block sizes, moderate improvements in scatterer size estimations were obtained using a multitaper method but this significantly increases the computational burden. It is critical to average power spectra from lateral A-lines for the improvement of scatterer size estimation. Averaging approximately 10 independent A-lines laterally, with an axial window length 10 times the center frequency wavelength optimized tradeoffs between spatial resolution and the variance of scatterer size estimates. Applying the concept of a time-bandwidth product this suggests using analysis blocks that contain at least 30 independent samples of the echo signal. The estimation accuracy and precision depend on the ka range where k is the wave number and a is the effective scatterer size. This introduces an ROI depth dependency to the accuracy and precision because of preferential attenuation of higher frequency sound waves in tissue-like media. With the 5–13 MHz transducer ka ranged from 0.5 – 1.6 for scatterers in the test phantom, which is a favorable range, and the accuracy and precision of scatterer size estimations were both within ~5% using optimal analysis block dimensions. When the 4–9 MHz transducer was used, the ka value ranged from 0.3 to 0.8 – 1.1 for the experimental conditions, and the accuracy and precision were found to be ~10% and 10% – 25%, respectively. Although the experiments were done with two specific models of transducers on the test phantom, the results can be generalized to similar clinical arrays available from a variety of manufacturers and/or for different size of scatterers with similar ka range. PMID:20178900

  15. 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.

  16. 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.

  17. 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...

  18. Biomass pyrolysis processes: performance parameters and their influence on biochar system benefits 

    E-print Network

    Brownsort, Peter A

    2009-01-01

    This study focuses on performance of biomass pyrolysis processes for use in biochar systems. Objectives are to understand the range of control of such processes and how this affects potential benefits of pyrolysis biochar ...

  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. Forging a Foundation for the Future: Keeping Public Research Universitites Strong.

    E-print Network

    McPherson, Peter; Gobstein, Howard J.; Shulenburger, David E.

    2010-01-01

    Works | http://kuscholarworks.ku.edu Forging a Foundation for the Future: Keeping Public Research Universitites Strong. 2010 by Peter McPherson, Howard J. Gobstein and David Shuleburger This work has been made available by the University of Kansas Libraries... version can be found at the link below. McPerson, Peter; Gobstein, Howard J. & Shulenburger, David. 2006. “Forging a Foundation for the Future: Keeping Public Research Universitites Strong.” National Association of State Universities and Land...

  1. 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.

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

    SciTech Connect

    Adinel, Gavrus; Thien, Pham Duc; Henri, Francillette

    2011-01-17

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

  3. Identification of mass-transfer parameters and process simulation of SCP production process in airlift tower reactors with an external loop.

    PubMed

    Luttmann, R; Buchholz, H; Zakrzewski, W; Schügerl, K

    1982-04-01

    A distributed parameter model for simulation of SCP-production processes in tower reactors with an outer loop was developed by considering substrate, cell, and CO(2) balances in the liquid phase, and O(2) and CO(3) balances in the ges phase and taking into account variations of dissolved oxygen concentration, pressure, and k(L)a along the column, as well as double substrate Monod kinetics. This model was used to describe the cultivation of Hansenula polymorpha in a tower-loop reactor (height 275 cm, diameter 15 cm). Parameter identification and process simulation were carried out by a hybrid computer. The variation of identified mass transfer parameters with fermentation time and operation mode is considered employing ethanol and glucose substrate, respectively. Relationships among k(L)a, substrate concentration, and superficial gas velocity were developed to facilitate the layout and simulation of pilot-plant reactors. PMID:18546373

  4. 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.-

  5. Experimental design approach to the process parameter optimization for laser welding of martensitic stainless steels in a constrained overlap configuration

    NASA Astrophysics Data System (ADS)

    Khan, M. M. A.; Romoli, L.; Fiaschi, M.; Dini, G.; Sarri, F.

    2011-02-01

    This paper presents an experimental design approach to process parameter optimization for the laser welding of martensitic AISI 416 and AISI 440FSe stainless steels in a constrained overlap configuration in which outer shell was 0.55 mm thick. To determine the optimal laser-welding parameters, a set of mathematical models were developed relating welding parameters to each of the weld characteristics. These were validated both statistically and experimentally. The quality criteria set for the weld to determine optimal parameters were the minimization of weld width and the maximization of weld penetration depth, resistance length and shearing force. Laser power and welding speed in the range 855-930 W and 4.50-4.65 m/min, respectively, with a fiber diameter of 300 ?m were identified as the optimal set of process parameters. However, the laser power and welding speed can be reduced to 800-840 W and increased to 4.75-5.37 m/min, respectively, to obtain stronger and better welds.

  6. 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…

  7. Mechanization of the Grit Blasting Process for Thermal Spray Coating Applications: A Parameter Study

    NASA Astrophysics Data System (ADS)

    Begg, Henry; Riley, Melissa; de Villiers Lovelock, Heidi

    2015-10-01

    The bond strength between a thermal spray coating and substrate is critical for many applications and is dependent on good substrate surface preparation and optimized spray parameters. While spray parameters are usually carefully monitored and controlled, most surface preparation is carried out by manual grit blasting, with little or no calibration of blast parameters. Blasting is currently highly dependent on operator skill and often surface finish is only assessed visually, meaning a consistent, reproducible surface profile cannot be guaranteed. This paper presents investigations on the effect of blast parameters (including blast pressure, standoff distance, media feed rate, blast angle, traverse speed, and media size) on surface profile for seven different metallic substrates using a mechanized, robotic blasting system and employing a brown fused alumina blast medium. Substrates were characterized using non-contact focus variation microscopy. Average surface roughness was found to be most affected by blast pressure, media size, and traverse speed, while changes to media feed rate and standoff distance had a limited effect on surface profile. Changes to blast angle resulted in limited change to average roughness, but microscopy examinations suggested a change in the mechanism of material removal.

  8. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-08-01

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

  11. Influence of some formulation and process parameters on the stability of lysozyme incorporated in corn flour- or corn starch-based extruded materials prepared by melt blending processing.

    PubMed

    Jbilou, Fouzia; Galland, Sophie; Telliez, Camille; Akkari, Zied; Roux, Roselyne; Oulahal, Nadia; Dole, Patrice; Joly, Catherine; Degraeve, Pascal

    2014-12-01

    In order to obtain an antimicrobial biodegradable material, corn flour was extruded with 1% of lysozyme. Since the limited stability of natural preservatives such as lysozyme is a common bottleneck to the elaboration of active biomaterials by melt blending processes, the influence of formulation and of extrusion processing temperature on its residual enzymatic activity was investigated. To assess the contribution of process parameters such as temperature, shear stress and of related formulation parameters such as glycerol and moisture contents, the stability of lysozyme following its extrusion or its thermoforming with plasticized corn starch or thermal treatments in aqueous glycerol solutions was also studied. Increasing glycerol content from 25% to 30% significantly limited inactivation of lysozyme during extrusion, while increasing initial moisture content of the mixture from 14.5% to 28.5% had the opposite effect. These observations open the possibility to prepare active materials retaining more than 60±7% of initial lysozyme activity. PMID:25442947

  12. Femtosecond laser ablation properties of transparent materials: impact of the laser process parameters on the machining throughput

    NASA Astrophysics Data System (ADS)

    Matylitsky, V. V.; Hendricks, F.; Aus der Au, J.

    2013-03-01

    High average power, high repetition rate femtosecond lasers with ?J pulse energies are increasingly used for bio-medical and material processing applications. With the introduction of femtosecond laser systems such as the SpiritTM platform developed by High Q Lasers and Spectra-Physics, micro-processing of solid targets with femtosecond laser pulses have obtained new perspectives for industrial applications [1]. The unique advantage of material processing with subpicosecond lasers is efficient, fast and localized energy deposition, which leads to high ablation efficiency and accuracy in nearly all kinds of solid materials. The study on the impact of the laser processing parameters on the removal rate for transparent substrate using femtosecond laser pulses will be presented. In particular, examples of micro-processing of poly-L-lactic acid (PLLA) - bio-degradable polyester and XensationTM glass (Schott) machined with SpiritTM ultrafast laser will be shown.

  13. Hot forging of graphite-carbide composites. Final report

    SciTech Connect

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

    1998-07-15

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

  14. Process modeling and parameter optimization using radial basis function neural network and genetic algorithm for laser welding of dissimilar materials

    NASA Astrophysics Data System (ADS)

    Ai, Yuewei; Shao, Xinyu; Jiang, Ping; Li, Peigen; Liu, Yang; Yue, Chen

    2015-08-01

    The welded joints of dissimilar materials have been widely used in automotive, ship and space industries. The joint quality is often evaluated by weld seam geometry, microstructures and mechanical properties. To obtain the desired weld seam geometry and improve the quality of welded joints, this paper proposes a process modeling and parameter optimization method to obtain the weld seam with minimum width and desired depth of penetration for laser butt welding of dissimilar materials. During the process, Taguchi experiments are conducted on the laser welding of the low carbon steel (Q235) and stainless steel (SUS301L-HT). The experimental results are used to develop the radial basis function neural network model, and the process parameters are optimized by genetic algorithm. The proposed method is validated by a confirmation experiment. Simultaneously, the microstructures and mechanical properties of the weld seam generated from optimal process parameters are further studied by optical microscopy and tensile strength test. Compared with the unoptimized weld seam, the welding defects are eliminated in the optimized weld seam and the mechanical properties are improved. The results show that the proposed method is effective and reliable for improving the quality of welded joints in practical production.

  15. Process modeling and parameter optimization using radial basis function neural network and genetic algorithm for laser welding of dissimilar materials

    NASA Astrophysics Data System (ADS)

    Ai, Yuewei; Shao, Xinyu; Jiang, Ping; Li, Peigen; Liu, Yang; Yue, Chen

    2015-11-01

    The welded joints of dissimilar materials have been widely used in automotive, ship and space industries. The joint quality is often evaluated by weld seam geometry, microstructures and mechanical properties. To obtain the desired weld seam geometry and improve the quality of welded joints, this paper proposes a process modeling and parameter optimization method to obtain the weld seam with minimum width and desired depth of penetration for laser butt welding of dissimilar materials. During the process, Taguchi experiments are conducted on the laser welding of the low carbon steel (Q235) and stainless steel (SUS301L-HT). The experimental results are used to develop the radial basis function neural network model, and the process parameters are optimized by genetic algorithm. The proposed method is validated by a confirmation experiment. Simultaneously, the microstructures and mechanical properties of the weld seam generated from optimal process parameters are further studied by optical microscopy and tensile strength test. Compared with the unoptimized weld seam, the welding defects are eliminated in the optimized weld seam and the mechanical properties are improved. The results show that the proposed method is effective and reliable for improving the quality of welded joints in practical production.

  16. Processing of interference images at the control of surface parameters of optical fiber components

    NASA Astrophysics Data System (ADS)

    Filipenko, Alexander; Nevludov, Igor; Sicheva, Oksana

    2008-03-01

    The control of a critical surfaces condition of fiber optic components is carried out by a method of two-beam interference under the scheme of Michelson interferometer. Ratios that connect surfaces form parameters with characteristics of interference images are resulted. The technique of useful information component distinguishing from a mix of interference signal with noise and a background of measurement that is based on use of bandpass Butterworth filters is offered and investigated.

  17. Effect of process parameters on properties of argon–nitrogen plasma for titanium nitride film deposition

    SciTech Connect

    Saikia, Partha; Kakati, Bharat

    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.

  18. 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.

  19. Improved Warm-Working Process For An Iron-Base Alloy

    NASA Technical Reports Server (NTRS)

    Cone, Fred P.; Cryns, Brendan J.; Miller, John A.; Zanoni, Robert

    1992-01-01

    Warm-working process produces predominantly unrecrystallized grain structure in forgings of iron-base alloy A286 (PWA 1052 composition). Yield strength and ultimate strength increased, and elongation and reduction of area at break decreased. Improved process used on forgings up to 10 in. thick and weighing up to 900 lb.

  20. A pass planning method for multi-hit stretching of heavy forgings by integration of a semi-analytical technique and degrees-reduced finite element

    NASA Astrophysics Data System (ADS)

    Cui, Zhenshan; Chen, Wen; Sui, Dashan; Liu, Juan

    2013-05-01

    A pass planning method for multi-pass and multi-hit stretching of heavy forgings is proposed, which composes of a semi-analytical procedure and a degrees-reduced finite element code. The semi-analytical procedure is based on a kinematically admissible velocity and Markov variational principle, and can be applied to roughly calculate the deformed shape and working force for stretch forging process for work-piece which has vertical and lateral symmetrical lines in cross-section. Meanwhile, in order to obtain the distributions of metal flow, temperature, strain and stress in detail, a degrees-reduced thermo-mechanical coupled rigid finite element code is developed. In this code, the instantaneous deformation zone is specially extracted from the total domain and simulated for metal flow, while the total domain is used to simulate the evolution of thermal field. Taking the semi-analytical method as a solver, the pass planning procedure for stretch forging is developed, and the degrees-reduced finite element code is used as a supplement to check the rationality of the planed pass schedule. An example is implemented to demonstrate the application of the proposed technique.

  1. 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.

  2. Standardization of process parameters for a chemical reaction using neutron activation analysis technique

    NASA Astrophysics Data System (ADS)

    Dokhale, P. A.; Bhoraskar, V. N.

    1996-08-01

    The chemical process to convert polyepichlorohydrin (PECH) into a glycidyl azide polymer (GAP) has been standardized by measuring the relative concentrations of nitrogen, chlorine and oxygen with the fast neutron activation analysis technique. For comparison PECH and GAP samples were also analysed by IR spectroscopy. The results indicate that, for standardization of the present chemical process, the fast neutron activation analysis technique is superior to IR spectroscopy. In this paper the techniques used to analyse the samples are described in detail but the information on the actual chemical process adopted is provided in brief.

  3. 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.

  4. On parameter estimation in a diffusion process with piecewise constant coefficients

    E-print Network

    . It is used in pharmaceutical research to estimate the rate by which certain drugs travel through thin with piecewise constant coefficients modelling the penetration process of drugs through thin membranes. Its

  5. Forming a lutein nanodispersion via solvent displacement method: The effects of processing parameters and emulsifiers with different stabilizing mechanisms.

    PubMed

    Tan, Tai Boon; Yussof, Nor Shariffa; Abas, Faridah; Mirhosseini, Hamed; Nehdi, Imededdine Arbi; Tan, Chin Ping

    2016-03-01

    A solvent displacement method was used to prepare lutein nanodispersions. The effects of processing parameters (addition method, addition rate, stirring time and stirring speed) and emulsifiers with different stabilizing mechanisms (steric, electrostatic, electrosteric and combined electrostatic-steric) on the particle size and particle size distribution (PSD) of the nanodispersions were investigated. Among the processing parameters, only the addition method and stirring time had significant effects (p<0.05) on the particle size and PSD. For steric emulsifiers, Tween 20, 40, 60 and 80 were used to produce nanodispersions successfully with particle sizes below 100nm. Tween 80 (steric) was then chosen for further comparison against sodium dodecyl sulfate (SDS) (electrostatic), sodium caseinate (electrosteric) and SDS-Tween 80 (combined electrostatic-steric) emulsifiers. At the lowest emulsifier concentration of 0.1%, all the emulsifiers invariably produced stable nanodispersions with small particle sizes (72.88-142.85nm) and narrow PSDs (polydispersity index<0.40). PMID:26471574

  6. Molecular Dynamics Simulation of Flattening Process of a High-Temperature, High-Speed Droplet—Influence of Impact Parameters

    NASA Astrophysics Data System (ADS)

    Shimizu, J.; Ohmura, E.; Kobayashi, Y.; Kiyoshima, S.; Eda, H.

    2007-12-01

    Three-dimensional molecular dynamics simulation was conducted to clarify at an atomic level the flattening process of a high-temperature droplet impacting a substrate at high speed. The droplet and the substrate were assumed to consist of pure aluminum, and the Morse potential was postulated between a pair of aluminum atoms. In this report, the influence of the impact parameters such as the droplet velocity and the droplet diameter on flattening behavior were analyzed. As a result, the following representative conclusions were obtained: (a) the flattening ratio increases in proportion to the droplet velocity and the droplet diameter; (b) the flattening ratio for nanosized droplet can be reorganized by the same dimensionless parameters of the proper physical properties, such as the viscosity and the surface tension, as those used in the macroscopic flattening process.

  7. 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.

  8. Taguchi's off line method and Multivariate loss function approach for quality management and optimization of process parameters -A review

    NASA Astrophysics Data System (ADS)

    Bharti, P. K.; Khan, M. I.; Singh, Harbinder

    2010-10-01

    Off-line quality control is considered to be an effective approach to improve product quality at a relatively low cost. The Taguchi method is one of the conventional approaches for this purpose. Through this approach, engineers can determine a feasible combination of design parameters such that the variability of a product's response can be reduced and the mean is close to the desired target. The traditional Taguchi method was focused on ensuring good performance at the parameter design stage with one quality characteristic, but most products and processes have multiple quality characteristics. The optimal parameter design minimizes the total quality loss for multiple quality characteristics. Several studies have presented approaches addressing multiple quality characteristics. Most of these papers were concerned with maximizing the parameter combination of signal to noise (SN) ratios. The results reveal the advantages of this approach are that the optimal parameter design is the same as the traditional Taguchi method for the single quality characteristic; the optimal design maximizes the amount of reduction of total quality loss for multiple quality characteristics. This paper presents a literature review on solving multi-response problems in the Taguchi method and its successful implementation in various industries.

  9. A new topological parameter for monitoring subtle aggregation events in host-guest inclusion processes

    NASA Astrophysics Data System (ADS)

    Novato, Willian T. G.; De Almeida, Wagner B.; Dos Santos, Hélio F.

    2012-02-01

    Supramolecular complexes with cyclodextrin (CD) have been the subject of considerable research in the material and life sciences. The dynamics of systems are difficult to characterise, therefore, knowledge of the molecular features governing the host-guest equilibrium might aid in the design and practical application of the resulting inclusion complexes. In this Letter, we present a new topological parameter based on simple trigonometric considerations to be used to monitor subtle host-guest inclusion events along the molecular dynamics trajectory. The new topological descriptor, called vector-?, was applied to amphetamine@?/?-CD inclusion complexes, providing interesting insights on the host-guest equilibrium.

  10. Application of physicochemical properties and process parameters in the development of a neural network model for prediction of tablet characteristics.

    PubMed

    Sovány, Tamás; Papós, Kitti; Kása, Péter; Ili?, Ilija; Sr?i?, Stane; Pintye-Hódi, Klára

    2013-06-01

    The importance of in silico modeling in the pharmaceutical industry is continuously increasing. The aim of the present study was the development of a neural network model for prediction of the postcompressional properties of scored tablets based on the application of existing data sets from our previous studies. Some important process parameters and physicochemical characteristics of the powder mixtures were used as training factors to achieve the best applicability in a wide range of possible compositions. The results demonstrated that, after some pre-processing of the factors, an appropriate prediction performance could be achieved. However, because of the poor extrapolation capacity, broadening of the training data range appears necessary. PMID:23413109

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  12. Microbiological, physicochemical and sensory parameters of dry fermented sausages manufactured with high hydrostatic pressure processed raw meat.

    PubMed

    Omer, M K; Prieto, B; Rendueles, E; Alvarez-Ordoñez, A; Lunde, K; Alvseike, O; Prieto, M

    2015-10-01

    The aim of this trial was to describe physicochemical, microbiological and organoleptic characteristics of dry fermented sausages produced from high hydrostatic pressure (HHP) pre-processed trimmings. During ripening of the meat products pH, weight, water activity (aw), and several microbiological parameters were measured at zero, eight, fifteen days and after 6weeks. Sensory characteristics were estimated at day 15 and after six weeks by a test panel by using several sensory tests. Enterobacteriaceae were not detected in sausages from HHP-processed trimmings. Fermentation was little affected, but weight and aw of the HHP-processed sausages decreased faster during ripening. HHP-treated sausages were consistently less favoured than non HHP-treated sausages, but the strategy may be an alternative approach if the process is optimized. PMID:26093224

  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. Analysis of process parameter effect on DIBL in n-channel MOSFET device using L27 orthogonal array

    NASA Astrophysics Data System (ADS)

    Salehuddin, F.; Kaharudin, K. E.; Zain, A. S. M.; Yamin, A. K. Mat; Ahmad, I.

    2014-10-01

    In this research, the effect of the process parameters variation on drain induced barrier lowering (DIBL) was investigated. The fabrication of the transistor device was performed using TCAD simulator, consisting of ATHENA and ATLAS modules. These two modules were combined with Taguchi method to optimize the process parameters. The setting of process parameters was determined by using the orthogonal array of L27 in Taguchi Method. In NMOS device, the most dominant or significant factors for S/N Ratio are halo implant energy, S/D implant dose and S/D implant energy. Meanwhile, the S/N Ratio values of DIBL after the optimization approaches for array L27 is 29.42 dB. In L27 experiments, DIBL value for n-channel MOSFET device after optimizations approaches is +37.8 mV. The results obtained were satisfied to be small as expected. As conclusions, by setting up design of experiment with the Taguchi Method and TCAD simulator, the optimal solutions on DIBL for the robust design recipe of 32nm n-channel MOSFET device was successfully achieved.

  16. The influence of friction stir processing parameters on microstructure of as-cast NiAl bronze

    NASA Astrophysics Data System (ADS)

    Oh-Ishi, Keiichiro; McNelley, Terry R.

    2005-06-01

    The influence of friction stir processing (FSP) parameters on the evolution of microstructure in an equilibrium-cooled, as-cast NiAl bronze (NAB) material was evaluated by optical microscopy (OM) and transmission electron microscopy (TEM) methods. A threaded pin tool was employed and tool rotation and traversing rates were varied in order to examine the spatial variation of stir zone microstructures in relation to FSP parameters. For processing at low rotation and traversing rates, the microstructure throughout the stir zone consists of elongated and banded grains of the primary ? and transformation products of the ? phase. Such microstructures reflect severe deformation at temperatures up to ˜900 °C in the ?+ ? two-phase region for this NAB material. Increasing rotation and traversing rates, coarse Widmanstätten ? near the surface in contact with the tool became apparent. The appearance of this constituent reflects nearly complete transformation to ? during FSP with peak temperatures of ˜1000 °C. Also, complex stir zone flow patterns, often referred to as onion ring structures, become distinct in the mid regions of the stir zones as rotation and traversing rates increase. Schematic representations illustrating the effect of FSP parameters on thermal cycles at various locations in stir zones were prepared based on microstructure observations. Thus, processing at higher rotation and traversing rates results in higher peak temperatures near the surface in contact with the tool but also in steeper temperature gradients when compared to lower rotation and traversing rates.

  17. 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.

  18. 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.

  19. 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.

  20. Design of experiments reveals critical parameters for pilot-scale freeze-and-thaw processing of L-lactic dehydrogenase.

    PubMed

    Roessl, Ulrich; Humi, Sebastian; Leitgeb, Stefan; Nidetzky, Bernd

    2015-09-01

    Freezing constitutes an important unit operation of biotechnological protein production. Effects of freeze-and-thaw (F/T) process parameters on stability and other quality attributes of the protein product are usually not well understood. Here a design of experiments (DoE) approach was used to characterize the F/T behavior of L-lactic dehydrogenase (LDH) in a 700-mL pilot-scale freeze container equipped with internal temperature and pH probes. In 24-hour experiments, target temperature between -10 and -38°C most strongly affected LDH stability whereby enzyme activity was retained best at the highest temperature of -10°C. Cooling profile and liquid fill volume also had significant effects on LDH stability and affected the protein aggregation significantly. Parameters of the thawing phase had a comparably small effect on LDH stability. Experiments in which the standard sodium phosphate buffer was exchanged by Tris-HCl and the non-ionic surfactant Tween 80 was added to the protein solution showed that pH shift during freezing and protein surface exposure were the main factors responsible for LDH instability at the lower freeze temperatures. Collectively, evidence is presented that supports the use of DoE-based systematic analysis at pilot scale in the identification of F/T process parameters critical for protein stability and in the development of suitable process control strategies. PMID:25820483

  1. Initial condition and parameter estimation in physical 'on off' processes by variational data assimilation

    NASA Astrophysics Data System (ADS)

    Wang, Jiafeng; Mu, Mu; Zheng, Qin

    2005-10-01

    In this paper we investigate the feasibility of using the variational data assimilation method to estimate both the initial condition and parameter in an idealized simple model with parametrized discontinuity. A method based on the non-linear perturbation equation (NPE) is applied to calculate the gradient of the cost function with respect to the control variables used in the minimization procedure. The results obtained by this method and by the conventional treatment (ignoring the variation of the switch point due to the perturbation in initial condition, i.e. keeping the switching point in the tangent linear model the same as in the basic state) are compared through numerical experiment. Because the cost function could have artificial minima after time discretization, the optimization algorithm combined with the NPE method is less sensitive to the first guess in retrieving the optimal initial condition and parameter value. It is shown that the gradient computation deserves consideration when there are discontinuities in the model used in variational data assimilation.

  2. 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

  3. Closed Die Deformation Behavior of Cylindrical Iron-Alumina Metal Matrix Composites During Cold Sinter Forging

    NASA Astrophysics Data System (ADS)

    Prasanna Kumar, Undeti Jacob; Gupta, Pallav; Jha, Arun Kant; Kumar, Devendra

    2015-09-01

    The present paper aims to study the closed die deformation behavior of cylindrical Fe-Al2O3 metal matrix composites (MMCs). Closed die was manufactured by machining the high carbon steel block followed by oil quenching and then finishing. Samples sintered at a temperature of 1100 °C for 1 h were characterized with X-ray diffraction and scanning electron microscopy, which showed the formation of Fe, Al2O3 and nano size FeAl2O4 phases respectively. Density and hardness of the composite samples were determined after sintering. Closed die deformation studies of the prepared composite samples were carried under three different interfacial frictional conditions i.e. dry, solid lubricating and liquid lubricating. Hardness, density and metallographic characterizations were also done for the deformed samples. On comparing the micrographs of the samples before and after deformation it was revealed that in deformed specimens recrystallization has taken place due to the difference in the energy between the strained iron matrix and unstrained alumina reinforcement during closed die forging process. Experimental density of the samples was also verified with the theoretical density using the standard equations. It is expected that the results of the present investigations will be helpful in developing quality MMC components for wide industrial applications.

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

    NASA Astrophysics Data System (ADS)

    Falloon, Garry

    2013-12-01

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

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

    E-print Network

    characteristic in a dry material form compared to spools of fiber. This in turn influences the processing of wind turbines. This is in contrast to the 106 cycles to failure often chosen for other machine in dimensions, were manufactured using hand layup procedures on a flat, level aluminum plate. The fabric

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Watershed models typically are evaluated solely through comparison of in-stream water and nutrient fluxes with measured data using established performance criteria, whereas processes and responses within the interior of the watershed that govern these global fluxes often are neglected. Due to the l...

  7. 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

  8. Testing of New Materials and Computer Aided Optimization of Process Parameters and Clamping Device During Predevelopment of Laser Welding Processes

    NASA Astrophysics Data System (ADS)

    Weidinger, Peter; Günther, Kay; Fitzel, Martin; Logvinov, Ruslan; Ilin, Alexander; Ploshikhin, Vasily; Hugger, Florian; Mann, Vincent; Roth, Stephan; Schmidt, Michael

    The necessity for weight reduction in motor vehicles in order to save fuel consumption pushes automotive suppliers to use materials of higher strength. Due to their excellent crash behavior high strength steels are increasingly applied in various structures. In this paper some predevelopment steps for a material change from a micro alloyed to dual phase and complex phase steels of a T-joint assembly are displayed. Initially the general weldability of the materials regarding pore formation, hardening in the heat affected zone and hot cracking susceptibility is discussed. After this basic investigation, the computer aided design optimization of a clamping device is shown, in which influences of the clamping jaw, the welding position and the clamping forces upon weld quality are presented. Finally experimental results of the welding process are displayed, which validate the numerical simulation.

  9. Effects of processing parameters on the levitation force of melt-processed YBa{sub 2}Cu{sub 3}O{sub {ital x}}

    SciTech Connect

    Varanasi, C.; McGinn, P.J.; Pavate, V.; Kvam, E.P.

    1995-09-01

    Melt processing of YBa{sub 2}Cu{sub 3}O{sub {ital x}} (Y-123) with a NdBa{sub 2}Cu{sub 3}O{sub {ital x}}-123 single-crystal seed has been used to grow large single-grain Y-123 samples. Processing parameters have been varied to observe the resulting differences in the levitation force of the samples. Increased hold time above the peritectic temperature and increased undercooling temperature have been observed to be beneficial in enhancing the levitation force of the samples. The levitation force measurements have been correlated with magnetization measurements on the crushed domains.

  10. Optimization of parameters in the emulsification process by two different methods.

    PubMed

    Carlotti, M E; Pattarino, F; Gasco, M R; Brusasca, P

    1993-12-01

    Synopsis An O/W emulsion with a lipopeptidic emulsifier was optimized by means of two different methods, specifically by experimental design and by selective variation of the parameters. Two optimized emulsions were obtained; they had similar values of emulsification (time and rate of homogenization) and amounts of components. Résumé Une émulsion O/E, avec un lipopeptide comme tensioactif, a été optimisée par deux méthodes d'optimisation différentes, notamment par l'experimental design et par la variation selective de certain paramètres. Deux émulsions optimisées ont été ainsi obtenues: ces émulsions ont des valeurs d'emulsification (temp et vitesse d'homogénéisation) et des quantités des composantes très proches. PMID:19281615

  11. Effect of process intensifying parameters on the hydrodynamic cavitation based degradation of commercial pesticide (methomyl) in the aqueous solution.

    PubMed

    Raut-Jadhav, Sunita; Saini, Daulat; Sonawane, Shirish; Pandit, Aniruddha

    2016-01-01

    Methomyl, a carbamate pesticide, is classified as a pesticide of category-1 toxicity and hence shows harmful effects on both human and aquatic life. In the present work, the degradation of methomyl has been studied by using hydrodynamic cavitation reactor (HC) and its combination with intensifying agents such as H2O2, fenton reagent and ozone (hybrid processes). Initially, the optimization of operating parameters such pH and inlet pressure to the cavitating device (circular venturi) has been carried out for maximizing the efficacy of hydrodynamic cavitation. Further degradation study of methomyl by the application of hybrid processes was carried out at an optimal pH of 2.5 and the optimal inlet pressure of 5 bar. Significant synergetic effect has been observed in case of all the hybrid processes studied. Synergetic coefficient of 5.8, 13.41 and 47.6 has been obtained by combining hydrodynamic cavitation with H2O2, fenton process and ozone respectively. Efficacy of individual and hybrid processes has also been obtained in terms of energy efficiency and extent of mineralization. HC+Ozone process has proved to be the most effective process having highest synergetic coefficient, energy efficiency and the extent of mineralization. The study has also encompassed the identification of intermediate by-products generated during the degradation and has proposed the probable degradation pathway. It has been conclusively established that hydrodynamic cavitation in the presence of intensifying agents can effectively be used for complete degradation of methomyl. PMID:26384910

  12. 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.

  13. Some Working Parameters and Energy Use in a Pistachio Nut Processing Plant: A Case Study

    NASA Astrophysics Data System (ADS)

    Polat, Refik; Erol Ak, Bekir; Acar, Izzet

    This study was performed with the objective to investigate the work process, work capacity, work effectiveness, energy consumption and labor force requirements of basic units such as washing, dehulling, sorting, separating, roasting and packing in a pistachio processing plant which has been mechanized in the last years. As a result of this study, the work capacity in washing, sorting, breaking, drying, separating units was found to be 1.5, 1.5, 2, 1, 1.6 t h-1, respectively. The work effectiveness in sorting and breaking units was found to be 95% and that of separating unit was 99%. The total energy consumption of the units was found to be 20.42 kW h-1 and the total labor force requirement was found to be five workers.

  14. Effect of processing parameters on the electrophoretic deposition of carbon black nanoparticles in moderately viscous systems.

    PubMed

    Modi, Satyam; Wei, Ming; Mead, Joey L; Barry, Carol M F

    2011-03-15

    Polymer-melt-based manufacturing processes for nanostructures offer high-rate, environmentally friendly, and commercially viable alternatives to solution-based methods. In this work, electrophoresis of a model carbon black and polystyrene system with moderate viscosity was used to investigate the viability of adapting nanoassembly processes to the high viscosity environment of polymer melts. The presence of polystyrene did not prevent deposition of carbon black, but deposition rates decreased at shorter deposition times; deposition was not linear with increasing applied voltage; and greater solution concentrations reduced the critical voltages (i.e., the voltage at which the rate of deposition changed). X-ray photoelectron spectroscopy (XPS) results and comparison of experimental data with Hamaker's model showed that about 1.6% of the available polystyrene was initially deposited with the carbon black. At voltages above the critical voltage, the deposited mass was less than the Hamaker prediction, indicating the formation of electrically insulating layers on the electrodes. The overall behavior suggests that polymer melt-based processes could be employed for high-rate fabrication of nano-optical devices, biochemical sensors, and nanoelectronics. PMID:21280596

  15. Liquefaction of lignocellulosic biomass: solvent, process parameter, and recycle oil screening.

    PubMed

    van Rossum, Guus; Zhao, Wei; Castellvi Barnes, Maria; Lange, Jean-Paul; Kersten, Sascha R A

    2014-01-01

    The liquefaction of lignocellulosic biomass is studied for the production of liquid (transportation) fuels. The process concept uses a product recycle as a liquefaction medium and produces a bio-oil that can be co-processed in a conventional oil refinery. This all is done at medium temperature (? 300 °C) and pressure (? 60 bar). Solvent-screening experiments showed that oxygenated solvents are preferred as they allow high oil (up to 93% on carbon basis) and low solid yields (? 1-2% on carbon basis) and thereby outperform the liquefaction of biomass in compressed water and biomass pyrolysis. The following solvent ranking was obtained: guaiacol>hexanoic acid ? n-undecane. The use of wet biomass results in higher oil yields than dry biomass. However, it also results in a higher operating pressure, which would make the process more expensive. Refill experiments were also performed to evaluate the possibility to recycle the oil as the liquefaction medium. The recycled oil appeared to be very effective to liquefy the biomass and even surpassed the start-up solvent guaiacol, but became increasingly heavy and more viscous after each refill and eventually showed a molecular weight distribution that resembles that of refinery vacuum residue. PMID:24265195

  16. Identification of Forged Bank of England 20 Gbp Banknotes Using IR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sonnex, Emily

    2014-06-01

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

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

    NASA Technical Reports Server (NTRS)

    Filippi, A. M.

    1974-01-01

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

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

    PubMed

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

    2014-01-24

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    Bank of England notes of £20 denomination have been studied using infrared spectroscopy in order to generate a method to identify forged notes. An aim of this work was to develop a non-destructive method so that a small, compact Fourier transform infrared spectrometer (FT-IR) instrument could be used by bank workers, police departments or others such as shop assistants to identify forged notes in a non-lab setting. The ease of use of the instrument is the key to this method, as well as the relatively low cost. The presence of a peak at 1400 cm-1 arising from ?asym (CO32-) from the blank paper section of a forged note proved to be a successful indicator of the note's illegality for the notes that we studied. Moreover, differences between the spectra of forged and genuine £20 notes were observed in the ?(OH) (ca. 3500 cm-1), ?(Csbnd H) (ca. 2900 cm-1) and ?(Cdbnd O) (ca. 1750 cm-1) regions of the IR spectrum recorded for the polymer film covering the holographic strip. In cases where these simple tests fail, we have shown how an infrared microscope can be used to further differentiate genuine and forged banknotes by producing infrared maps of selected areas of the note contrasting inks with background paper.

  20. Stevia rebaudiana Bertoni as a natural antioxidant/antimicrobial for high pressure processed fruit extract: processing parameter optimization.

    PubMed

    Barba, Francisco José; Criado, María Nieves; Belda-Galbis, Clara Miracle; Esteve, María José; Rodrigo, Dolores

    2014-04-01

    Response surface methodology was used to evaluate the optimal high pressure processing treatment (300-500 MPa, 5-15 min) combined with Stevia rebaudiana (Stevia) addition (0-2.5% (w/v)) to guarantee food safety while maintaining maximum retention of nutritional properties. A fruit extract matrix was selected and Listeria monocytogenes inactivation was followed from the food safety point of view while polyphenoloxidase (PPO) and peroxidase (POD) activities, total phenolic content (TPC) and antioxidant capacity (TEAC and ORAC) were studied from the food quality point of view. A combination of treatments achieved higher levels of inactivation of L. monocytogenes and of the oxidative enzymes, succeeding in completely inactivating POD and also increasing the levels of TPC, TEAC and ORAC. A treatment of 453 MPa for 5 min with a 2.5% (w/v) of Stevia succeeded in inactivating over 5 log cycles of L. monocytogenes and maximizing inactivation of PPO and POD, with the greatest retention of bioactive components. PMID:24262555

  1. Rolling Process Modeling Report. Finite-Element Model Validation and Parametric Study on various Rolling Process parameters

    SciTech Connect

    Soulami, Ayoub; Lavender, Curt A.; Paxton, Dean M.; Burkes, Douglas

    2015-06-15

    Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum alloy plate-type fuel for high-performance research reactors in the United States. This work supports the U.S. Department of Energy National Nuclear Security Administration’s Office of Material Management and Minimization Reactor Conversion Program. This report documents modeling results of PNNL’s efforts to perform finite-element simulations to predict roll-separating forces for various rolling mill geometries for PNNL, Babcock & Wilcox Co., Y-12 National Security Complex, Los Alamos National Laboratory, and Idaho National Laboratory. The model developed and presented in a previous report has been subjected to further validation study using new sets of experimental data generated from a rolling mill at PNNL. Simulation results of both hot rolling and cold rolling of uranium-10% molybdenum coupons have been compared with experimental results. The model was used to predict roll-separating forces at different temperatures and reductions for five rolling mills within the National Nuclear Security Administration Fuel Fabrication Capability project. This report also presents initial results of a finite-element model microstructure-based approach to study the surface roughness at the interface between zirconium and uranium-10% molybdenum.

  2. Validation of cresis synthetic aperture radar processor and optimal processing parameters

    NASA Astrophysics Data System (ADS)

    Smith, Logan Sanders

    Sounding the ice sheets of Greenland and Antarctica is a vital component in determining the effect of global warming on sea level rise. Of particular importance are measurements of the bedrock topography of the outlet glaciers that transport ice from the ice sheet's interior to the margin where it calves into icebergs, contributing to sea level rise. These outlet glaciers are difficult to sound due to crevassing caused by the relatively fast movement of the ice in the glacial channel and higher signal attenuation caused by warmer ice. The Center for Remote Sensing of Ice Sheets (CReSIS) uses multi-channel airborne radars which employ methods for achieving better resolution and signal-to-noise ratio (SNR) to better sound outlet glaciers. Synthetic aperture radar (SAR) techniques are used in the along-track dimension, pulse compression in the range dimension, and an antenna array in the cross-track dimension. CReSIS has developed the CReSIS SAR processor (CSARP) to effectively and efficiently process the data collected by these radars in each dimension. To validate the performance of this processor a SAR simulator was developed with the functionality to test the implementation of the processing algorithms in CSARP. In addition to the implementation of this simulator for validation of processing the data in the along-track, cross-track and range dimensions, there are a number of data-dependent processing steps that can affect the quality of the final data product. CSARP was tested with an ideal simulated point target in white Gaussian noise. The SNR change achieved by range compression, azimuth compression, array combination with and without matched filtering, and lever arm application were all within .2 dB of the theoretical expectation. Channel equalization, when paired with noise-based matched filtering, provided 1-2 dB of gain on average but significantly less than the expected gain. Extending the SAR aperture length to sound bedrock will improve the along-track resolution, but at the expense of SNR. Increasing the taper of a window in the fast-time and slow-time will slightly improve the SNR of the data. Changing the relative permittivity used to process the data improved the resulting SNR by no more than 0.025 dB for the test dataset.

  3. 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.

  4. 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.

  5. 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.

  6. The effects of process parameters on yield and properties of iron nanoparticles from ferrocene in a low-pressure plasma

    NASA Astrophysics Data System (ADS)

    Panchal, V.; Lahoti, G.; Bhandarkar, U.; Neergat, M.

    2011-08-01

    The effects of process parameters on iron nanoparticle formation and properties while using ferrocene as a precursor in a low-pressure capacitively coupled plasma are investigated. The L18 array of the Taguchi method, followed by the L4 array, is used with the notional objective of increasing the yield of nanoparticles. A study of the size, shape and composition of the particles (using transmission electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, x-ray diffraction, CHON and inductively coupled plasma-atomic emission spectroscopy analysis) gives an insight into the role played by various process parameters. Pressure is the most critical parameter in increasing nanoparticle yield, whereas hydrogen flow plays a key role in determining the nanoparticle size and composition. Atomic hydrogen helps in removing amorphous carbon and reducing the nanoparticle size. RF power plays an important role in the dissociation of ferrocene thus also affecting the composition. Nanoparticles obtained using optimized conditions are a mixture of Fe3O4 and Fe2O3 with cluster size 25-40 nm in diameter that are further made up of 2-4 nm crystallites. Magnetic property measurements indicate that the nanoparticles are super-paramagnetic in nature.

  7. Preparation of hydroxyapatite nanoparticles by sol-gel method with optimum processing parameters

    SciTech Connect

    Yusoff, Yusriha Mohd; Salimi, Midhat Nabil Ahmad; Anuar, Adilah

    2015-05-15

    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(NO{sub 3}){sub 2}.4H{sub 2}O and phosphorous pentoxide, P{sub 2}O{sub 5}. 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.

  8. 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.

  9. 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

  10. Effect of breadmaking process on in vitro gut microbiota parameters in irritable bowel syndrome.

    PubMed

    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

  11. 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.

  12. Effect of process parameters on temperature distribution in twin-electrode TIG coupling arc

    NASA Astrophysics Data System (ADS)

    Zhang, Guangjun; Xiong, Jun; Gao, Hongming; Wu, Lin

    2012-10-01

    The twin-electrode TIG coupling arc is a new type of welding heat source, which is generated in a single welding torch that has two tungsten electrodes insulated from each other. This paper aims at determining the distribution of temperature for the coupling arc using the Fowler-Milne method under the assumption of local thermodynamic equilibrium. The influences of welding current, arc length, and distance between both electrode tips on temperature distribution of the coupling arc were analyzed. Based on the results, a better understanding of the twin-electrode TIG welding process was obtained.

  13. 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.

  14. 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

  15. Optimization of Processing Parameters in ECM of Die Tool Steel Using Nanofluid by Multiobjective Genetic Algorithm.

    PubMed

    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 mm(3)/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 mm(3)/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

  16. Reducing Uncertainty in Estimates of Environmental Parameters From Ambient Noise Using Statistical Array Processing

    NASA Astrophysics Data System (ADS)

    Menon, Ravishankar

    In recent years, extracting environmental information from diffuse ambient noise has become an increasingly viable alternative to traditional active source methods. Due to uncontrollable factors such as noise field directionality, presence of spatially compact sources and unknown medium properties, results from ambient noise processing are often biased and need careful interpretation. Thus it is important to develop robust approaches that can perform well in the presence of such detriments. The first part of the dissertation focuses on interpreting the coherence and attenuation estimates from seismic arrays. Adaptive array processing using stations from the Southern California Seismic Network is used to identify the presence of multiple seismic waves, namely the fundamental and first mode Rayleigh wave, and body waves. The spatial coherence function (SCF) is modeled as a linear superposition of these waves, with the proportions estimated from data. The SCF shows beating and phase cancellation effects due to the interactions between wavenumbers, which could be misinterpreted as attenuation. The array geometry is also shown to limit the ranges at which the coherence can be estimated well. The second part of the dissertation focuses on developing statistical techniques to mitigate the effects of spatially compact sources on the noise processing. Analytical expressions are derived for the asymptotic eigenvalues of the true spatial covariance matrix (CM) for a uniform line array in three and two dimensional isotropic noise fields with and without attenuation. Using random matrix theory, the asymptotic probability density of the eigenvalues of the sample covariance matrix (SCM) also is derived in each of these scenarios. These analytical results provide upperbounds for the noise eigenvalues of the SCM. In the third part of the dissertation, the analytical results are combined with a sequential hypothesis testing framework. This then is used to identify the outliers (which correspond to strong and spatially compact sources) in shallow water ocean acoustic data. The cross-correlation results after rejecting these outliers are shown to be unbiased and converge faster with a higher signal-to-noise ratio. The performance of the eigenvalue rejection technique under different noise model assumptions also is investigated.

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

    PubMed Central

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

    2005-01-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    SciTech Connect

    Dalder, E.N.C.; 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.

  20. What history reveals about Forge River pollution on Long Island, New York's south shore.

    PubMed

    Swanson, R Lawrence; Brownawell, B; Wilson, Robert E; O'Connell, Christine

    2010-06-01

    Fifty years ago, the Forge River and Moriches Bay, of Long Island's south shore lagoonal system, achieved notoriety when their polluted conditions were alluded to in a report of the US President's Science Advisory Committee (1965). The Woods Hole Oceanographic Institution investigated the bay throughout the 1950s, identifying duck farming as the cause of "objectionable", "highly contaminated" conditions of these waters. Much has changed: duck farming declined; the river was dredged to remove polluted sediments, improve navigation; and barrier island inlets stabilized. Yet, the river remains seasonally eutrophic. Why? This paper reviews what occurred in the Forge River watershed. While governments aggressively curtailed the impacts of duck pollution, they failed to manage development and sewage pollution. The Forge experience indicates that watershed management is a continuing governmental responsibility as development accelerates. Otherwise, we will always be looking for that instantaneous remediation that is usually not affordable and is socially contentious. PMID:20413134

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

    SciTech Connect

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

    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.

  2. 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.

  3. 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 distribution via subsequent thermomechanical forming. A plane-strain solution for analyzing the open-die response is used in a classical "slab" analysis of open-die forging. The analysis predicts the upsetting

  4. 76 FR 5331 - Forged Stainless Steel Flanges From India and Taiwan: Final Results of Sunset Reviews and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-31

    .... See Initiation of Five-Year (``Sunset'') Review, 75 FR 67082 (November 1, 2010). We did not receive a... Forged Stainless Steel Flanges From India, 59 FR 5994 (February 9, 1994) and Antidumping Duty Order: Certain Forged Stainless Steel Flanges From Taiwan, 59 FR 5995 (February 9, 1994). On January 23,...

  5. 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

    ... of institution (76 FR 168, January 3, 2011) of the subject five-year reviews was adequate and that... Heavy Forged Hand Tools From China; Scheduling of Expedited Five- Year Reviews Concerning the Antidumping Duty Orders on Heavy Forged Hand Tools From China. AGENCY: United States International...

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

    PubMed Central

    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

  7. Processing, stability, and kinetic parameters of C5a peptidase from Streptococcus pyogenes.

    PubMed

    Anderson, Elizabeth T; Wetherell, Michael G; Winter, Laurie A; Olmsted, Stephen B; Cleary, Patrick P; Matsuka, Yury V

    2002-10-01

    A recombinant streptococcal C5a peptidase was expressed in Escherichia coli and its catalytic properties and thermal stability were subjected to examination. It was shown that the NH2-terminal region of C5a peptidase (Asn32-Asp79/Lys90) forms the pro-sequence segment. Upon maturation the propeptide is hydrolyzed either via an autocatalytic intramolecular cleavage or by exogenous protease streptopain. At pH 7.4 the enzyme exhibited maximum activity in the narrow range of temperatures between 40 and 43 degrees C. The process of heat denaturation of C5a peptidase investigated by fluorescence and circular dichroism spectroscopy revealed that the protein undergoes biphasic unfolding transition with Tm of 50 and 70 degrees C suggesting melting of different parts of the molecule with different stability. Unfolding of the less stable structures was accompanied by the loss of proteolytic activity. Using synthetic peptides corresponding to the COOH-terminus of human complement C5a we demonstrated that in vitro peptidase catalyzes hydrolysis of two His67-Lys68 and Ala58-Ser59 peptide bonds. The high catalytic efficiency obtained for the SQLRANISHKDMQLGR extended peptide compared to the poor hydrolysis of its derivative Ac-SQLRANISH-pNA that lacks residues at P2'-P7' positions, suggest the importance of C5a peptidase interactions with the P' side of the substrate. PMID:12354115

  8. 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

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

    PubMed

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

    2015-03-01

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

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

    SciTech Connect

    Hanley, Tracey; Sutton, David; Karatchevtseva, Inna; Cookson, David; Burford, Robert; Knott, Robert

    2008-10-03

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

  11. Treatment of biodiesel wastewater by adsorption with commercial chitosan flakes: parameter optimization and process kinetics.

    PubMed

    Pitakpoolsil, Wipawan; Hunsom, Mali

    2014-01-15

    The possibility of using commercial chitosan flakes as an adsorbent for the removal of pollutants from biodiesel wastewater was evaluated. The effect of varying the adsorption time (0.5-5 h), initial wastewater pH (2-8), adsorbent dose (0.5-5.5 g/L) and mixing rate (120-350 rpm) on the efficiency of pollutant removal was explored by univariate analysis. Under the derived optimal conditions, greater than 59.3%, 87.9% and 66.2% of the biological oxygen demand (BOD), chemical oxygen demand (COD) and oil & grease, respectively, was removed by a single adsorption. Nevertheless, the remaining BOD, COD and oil & grease were still higher than the acceptable Thai government limits for discharge into the environment. When the treatment was repeated, a greater than 93.6%, 97.6% and 95.8% removal of the BOD, COD and oil & grease, respectively, was obtained. The reusability of commercial chitosan following NaOH washing (0.05-0.2 M) was not suitable, with less than 40% efficiency after just one recycling and declining rapidly thereafter. The adsorption kinetics of all pollutant types by the commercial chitosan flakes was controlled by a mixed process of diffusion and adsorption of the pollutants during the early treatment period (0-1.5 h) and then solely controlled by adsorption after 2 h. PMID:24412591

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

    SciTech Connect

    Christenson, Todd; Garino, Terry

    1999-06-25

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

  13. Effect of growth parameters on dislocation generation in InP single crystal grown by the vertical gradient freeze process

    SciTech Connect

    Gulluoglu, A.N. . Dept. of Material Science and Engineering); Tsai, C.T. . Dept. of Mechanical Engineering)

    1999-06-22

    The generation and multiplication of dislocations in an indium phosphide (InP) single crystal grown by the vertical gradient freeze (VGF) process is predicted using a crystallographic model. This model couples microscopic dislocation motion and multiplication to macroscopic plastic deformation during the crystal growth process. During growth of an InP crystal, dislocations are generated in the plastically deformed crystal as a result of crystallographic glide caused by excessive thermal stresses. The temperature fields are determined by solving the partial differential equation of heat conduction in a VGF crystal growth system. The effects of growth direction and growth parameters (i.e., imposed temperature gradients, crystal radius and growth rate) on dislocation generation and multiplication in an InP crystal are investigated. Dislocation density patterns on the cross section of an InP crystal are numerically calculated and compared with experimental observations.

  14. Photosynthetic and Ultrastructure Parameters of Maize Plants are Affected During the Phyto-Rhizoremediation Process of Degraded Metal Working Fluids.

    PubMed

    Grijalbo, Lucía; Gutierrez Mañero, Francisco Javier; Fernandez-Pascual, Mercedes; Lucas, Jose Antonio

    2015-12-01

    A phyto-rhizoremediation system using corn and esparto fiber as rooting support to remediate degraded metal working fluids (dMWFs) has been developed in the present study. In order to improve the process, plants were inoculated at the root level with bacteria either individually, and with a consortium of strains. All strains used were able to grow with MWFs. The results show that this system significantly lowers the Chemical Oxygen Demand below legal limits within 5 days. However, results were only improved with the bacterial consortium. Despite the effectiveness of the phyto-rhizoremediation process, plants are damaged at the photosynthetic level according to the photosynthetic parameters measured, as well as at the ultrastructure of the vascular cylinder and the Bundle Sheath Cells. Interestingly, the bacterial inoculation protects against this damage. Therefore, it seems that that the inoculation with bacteria can protect the plants against these harmful effects. PMID:26090801

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

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

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

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

    SciTech Connect

    CANNELL, G.R.

    2006-09-11

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

  17. Analysis of principal parameters of forest fires and identification of desertification process in semi-arid land in Algeria

    NASA Astrophysics Data System (ADS)

    Zegrar, Ahmed

    2013-10-01

    In semi arid land in Algeria the ecosystem of steppe presents a different vegetal formation, generally used for pasture, and the forest are in most time composed by species like Aleppo pine sparse. And seen climatic unfavourable conditions in zone and impact of forest fires; we notes deterioration of physical environment particularly, deterioration of natural forest. This deterioration of forests provokes an unbalance of environment witch provokes a process of deterioration advanced in the ultimate stadium is desertification. The specific regeneration of plants are influenced greatly by the regime of fire (season of fire, intensity, interval), who leads to the recuperation of the vegetation of meadow- fire, but in the most case there are unfavourable climatic conditions. In this survey we used satellite data for detection of zones with risk of forest fire and their influenced parameters witch permit generally a desertification process. A thematic detailed analysis of forests ecosystems well attended, some processing on the satellite data (2003) allowed us to identify and classifying the forests in there opinion components flowers. We identified ampleness of fire on this zone also. The parameters slope, the proximity to the road and the forests formations and fire regime were studied in the goal of determining the zones to risk of fire drill. A crossing of information in a geographic information system according to a very determined logic allowed us to classify the zones in degree of risk of fire. These results compared with image data (2011) permit to conclude that in semi arid land the forest ecosystem after fire becomes steppe courses permitting installation of process of desertification.

  18. 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

  19. 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

  20. 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.

  1. Influence of cutting parameters on the depth of subsurface deformed layer in nano-cutting process of single crystal copper.

    PubMed

    Wang, Quanlong; Bai, Qingshun; Chen, Jiaxuan; Su, Hao; Wang, Zhiguo; Xie, Wenkun

    2015-12-01

    Large-scale molecular dynamics simulation is performed to study the nano-cutting process of single crystal copper realized by single-point diamond cutting tool in this paper. The centro-symmetry parameter is adopted to characterize the subsurface deformed layers and the distribution and evolution of the subsurface defect structures. Three-dimensional visualization and measurement technology are used to measure the depth of the subsurface deformed layers. The influence of cutting speed, cutting depth, cutting direction, and crystallographic orientation on the depth of subsurface deformed layers is systematically investigated. The results show that a lot of defect structures are formed in the subsurface of workpiece during nano-cutting process, for instance, stair-rod dislocations, stacking fault tetrahedron, atomic clusters, vacancy defects, point defects. In the process of nano-cutting, the depth of subsurface deformed layers increases with the cutting distance at the beginning, then decreases at stable cutting process, and basically remains unchanged when the cutting distance reaches up to 24 nm. The depth of subsurface deformed layers decreases with the increase in cutting speed between 50 and 300 m/s. The depth of subsurface deformed layer increases with cutting depth, proportionally, and basically remains unchanged when the cutting depth reaches over 6 nm. PMID:26452371

  2. Influence of cutting parameters on the depth of subsurface deformed layer in nano-cutting process of single crystal copper

    NASA Astrophysics Data System (ADS)

    Wang, Quanlong; Bai, Qingshun; Chen, Jiaxuan; Su, Hao; Wang, Zhiguo; Xie, Wenkun

    2015-10-01

    Large-scale molecular dynamics simulation is performed to study the nano-cutting process of single crystal copper realized by single-point diamond cutting tool in this paper. The centro-symmetry parameter is adopted to characterize the subsurface deformed layers and the distribution and evolution of the subsurface defect structures. Three-dimensional visualization and measurement technology are used to measure the depth of the subsurface deformed layers. The influence of cutting speed, cutting depth, cutting direction, and crystallographic orientation on the depth of subsurface deformed layers is systematically investigated. The results show that a lot of defect structures are formed in the subsurface of workpiece during nano-cutting process, for instance, stair-rod dislocations, stacking fault tetrahedron, atomic clusters, vacancy defects, point defects. In the process of nano-cutting, the depth of subsurface deformed layers increases with the cutting distance at the beginning, then decreases at stable cutting process, and basically remains unchanged when the cutting distance reaches up to 24 nm. The depth of subsurface deformed layers decreases with the increase in cutting speed between 50 and 300 m/s. The depth of subsurface deformed layer increases with cutting depth, proportionally, and basically remains unchanged when the cutting depth reaches over 6 nm.

  3. 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.

  4. 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.

  5. Evolution of process control parameters during extended co-composting of green waste and solid fraction of cattle slurry to obtain growing media.

    PubMed

    Cáceres, Rafaela; Coromina, Narcís; Mali?ska, Krystyna; Marfà, Oriol

    2015-03-01

    This study aimed to monitor process parameters when two by-products (green waste - GW, and the solid fraction of cattle slurry - SFCS) were composted to obtain growing media. Using compost in growing medium mixtures involves prolonged composting processes that can last at least half a year. It is therefore crucial to study the parameters that affect compost stability as measured in the field in order to shorten the composting process at composting facilities. Two mixtures were prepared: GW25 (25% GW and 75% SFCS, v/v) and GW75 (75% GW and 25% SFCS, v/v). The different raw mixtures resulted in the production of two different growing media, and the evolution of process management parameters was different. A new parameter has been proposed to deal with attaining the thermophilic temperature range and maintaining it during composting, not only it would be useful to optimize composting processes, but also to assess the hygienization degree. PMID:25553571

  6. 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…

  7. 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…

  8. Planning and Health: Forging New Alliances in Building Healthy and Resilient Cities Susan Thompson1

    E-print Network

    New South Wales, University of

    1 Planning and Health: Forging New Alliances in Building Healthy and Resilient Cities Susan Wales, Australia, s.thompson@unsw.edu.au 2 City Futures Research Centre, University of New South Wales, Australia, jennifer.kent@unsw.edu.au 3 New South Wales Ministry of Health, Australia. claudine

  9. 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…

  10. 76 FR 66996 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Forging...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ..., see the related notice published in the Federal Register on May 24, 2011 (76 FR 30200). Interested...; Forging Machines ACTION: Notice. SUMMARY: The Department of Labor (DOL) is submitting the Occupational... Machines,'' to the Office of Management and Budget (OMB) for review and approval for continued use...

  11. 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.

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

    E-print Network

    Fillingim, Matthew

    Science Education and Outreach: Forging a Path to the Future ASP Conference Series, Vol. 431, Berkeley, CA 94720-7450, USA 2Center for Science Education, Space Sciences Laboratory, University) in collaboration with Education/Public Outreach specialists at the Center for Science Education at SSL (CSE

  13. Effect of technological factors on the properties of forged austenitic stainless steels

    SciTech Connect

    Napara-Volgina, S.G.

    1994-11-01

    The conditions for the production of austenitic stainless steel Kh18N10, Kh18N12M2, and Kh23N18 (i.e., Cr18Ni10, Cr18N12Mo2, and Cr23Ni18) by forging porous blanks have been studied and optimized. In many cases, the properties of these steels are determined by the production technology: the duration, temperature, and heating medium used in the presintering and the duration and temperature of the heating for forging the blanks. In each specific case the choice of fabrication conditions depends on the shape and purpose of the part. Simple parts with plane-parallel ends without changes in section along the height can be produced by hot forging without presintering of the powder blanks. Complex parts require hot forging at high temperatures (1150-1200{degrees}C) of presintered blanks. If the stainless steels do not have to meet stringent ductility requirements but must possess high strength, the blanks can be heated at 950-1050{degrees}C without a protective gas atmosphere.

  14. Jernberg Industries, Inc: Forging Facility Uses Plant-Wide Assessment to Aid Conversion to Lean Manufacturing

    SciTech Connect

    2004-10-01

    Jernberg Industries conducted a plant-wide assessment while converting to lean manufacturing at a forging plant. Seven projects were identified that could yield annual savings of $791,000, 64,000 MMBtu in fuel and 6 million kWh.

  15. Forge Welding of Magnesium Alloy to Aluminum Alloy Using a Cu, Ni, or Ti Interlayer

    NASA Astrophysics Data System (ADS)

    Yamagishi, Hideki; Sumioka, Junji; Kakiuchi, Shigeki; Tomida, Shogo; Takeda, Kouichi; Shimazaki, Kouichi

    2015-08-01

    The forge-welding process was examined to develop a high-strength bonding application of magnesium (Mg) alloy to aluminum (Al) alloy under high-productivity conditions. The effect of the insert material on the tensile strength of the joints, under various preheat temperatures and pressures, was investigated by analyzing the reaction layers of the bonded interface. The tensile strengths resulting from direct bonding, using pure copper (Cu), pure nickel (Ni), and pure titanium (Ti) inserts were 56, 100, 119, and 151 MPa, respectively. The maximum joint strength reached 93 pct with respect to the Mg cast billet. During high-pressure bonding, a microscopic plastic flow occurred that contributed to an anchor effect and the generation of a newly formed surface at the interface, particularly prominent with the Ti insert in the form of an oxide layer. The bonded interfaces of the maximum-strength inserts were investigated using scanning electron microscopy-energy-dispersive spectroscopy and electron probe microanalysis. The diffusion reaction layer at the bonded interface consisted of brittle Al-Mg intermetallics having a thickness of approximately 30 ?m. In contrast, for the three inserts, the thicknesses of the diffusion reaction layer were infinitely thin. For the pure Ti insert, exhibiting the maximum tensile strength value among the inserts tested, focused ion beam-transmission electron microscopy-EDS analysis revealed a 60-nm-thick Al-Ti reaction layer, which had formed at the bonded interface on the Mg alloy side. Thus, a high-strength Al-Mg bonding method in air was demonstrated, suitable for mass production.

  16. High-rate activated sludge system for carbon management - Evaluation of crucial process mechanisms and design parameters.

    PubMed

    Jimenez, Jose; Miller, Mark; Bott, Charles; Murthy, Sudhir; De Clippeleir, Haydee; Wett, Bernhard

    2015-12-15

    The high-rate activated sludge (HRAS) process is a technology suitable for the removal and redirection of organics from wastewater to energy generating processes in an efficient manner. A HRAS pilot plant was operated under controlled conditions resulting in concentrating the influent particulate, colloidal, and soluble COD to a waste solids stream with minimal energy input by maximizing sludge production, bacterial storage, and bioflocculation. The impact of important process parameters such as solids retention time (SRT), hydraulic residence time (HRT) and dissolved oxygen (DO) levels on the performance of a HRAS system was demonstrated in a pilot study. The results showed that maximum removal efficiencies of soluble COD were reached at a DO > 0.3 mg O2/L, SRT > 0.5 days and HRT > 15 min which indicates that minimizing the oxidation of the soluble COD in the high-rate activated sludge process is difficult. The study of DO, SRT and HRT exhibited high degree of impact on the colloidal and particulate COD removal. Thus, more attention should be focused on controlling the removal of these COD fractions. Colloidal COD removal plateaued at a DO > 0.7 mg O2/L, SRT > 1.5 days and HRT > 30 min, similar to particulate COD removal. Concurrent increase in extracellular polymers (EPS) production in the reactor and the association of particulate and colloidal material into sludge flocs (bioflocculation) indicated carbon capture by biomass. The SRT impacted the overall mass and energy balance of the high-rate process indicating that at low SRT conditions, lower COD mineralization or loss of COD content occurred. In addition, the lower SRT conditions resulted in higher sludge yields and higher COD content in the WAS. PMID:26260539

  17. Some matters concerned with selecting steam parameters and process-circuit solutions to optimize the parameters of steam turbine equipment and engineering design developments

    NASA Astrophysics Data System (ADS)

    Kultyshev, A. Yu.; Stepanov, M. Yu.; Polyaeva, E. N.

    2014-12-01

    The possibility and advantages of increasing steam pressure in the steam-turbine low-pressure loop for combined-cycle power plants are considered. The question about the advisability of developing and manufacturing steam turbines for being used in combined-cycle power units equipped with modern class F gas turbines for supercritical and ultrasupercritical steam parameters is raised.

  18. Modeling of selected ceramic processing parameters employed in the fabrication of 238PuO2 fuel pellets

    DOE PAGESBeta

    Brockman, R. A.; Kramer, D. P.; Barklay, C. D.; Cairns-Gallimore, D.; Brown, J. L.; Huling, J. C.; Van Pelt, C. E.

    2011-10-01

    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. The results of the modeling efforts will be discussed.« less

  19. The thermal expansion coefficient as a key design parameter for thermoelectric materials and its relationship to processing-dependent bloating

    SciTech Connect

    Ni, Jennifer E.; Case, Eldon D; Schmidt, Robert; Wu, Chun-I; Hogan, Timothy; Trejo, Rosa M; Kirkham, Melanie J; Lara-Curzio, Edgar; Kanatzidis, Mercouri G.

    2013-01-01

    The coefficient of thermal expansion (CTE) is a key design parameter for thermoelectric (TE) materials, especially in energy harvesting applications since stresses generated by CTE mismatch, thermal gradients, and thermal transients scale with the CTE of the TE material. For the PbTe PbS-based TE material (Pb 0.95 Sn 0.05 Te) 0.92(PbS) 0.08 0.055 % PbI 2 over the temperature ranges of 293 543 and 293 773 K, a CTE, alpha avg , of 21.4 0.3 x 10-6 K-1 was measured using (1) dilatometry and (2) high-temperature X-ray diffraction (HT-XRD) for powder and bulk specimens. The CTE values measured via dilatometry and HT-XRD are similar to the literature values for other Pb-based chalcogenides. However, the processing technique was found to impact the thermal expansion such that bloating (which leads to a hysteresis in thermal expansion) occurred for hot pressed billets heated to temperatures [603 K while specimens fabricated by pulsed electric current sintering and as-cast specimens did not show a bloating-modified thermal expansion even for temperatures up to 663 K. The relationship of bloating to the processing techniques is discussed, along with a pos- sible mechanism for inhibiting bloating in powder processed specimens.

  20. Statistical Parameters Effects on Photocatalytic Degradation of Rhodamine 6G Dye with Hexagonal Zinc Oxide Nanorods Synthesized via Solution Process

    NASA Astrophysics Data System (ADS)

    Wahab, Rizwan; Khan, Farheen

    2014-11-01

    Hexagonal-shaped zinc oxide nanorods (HNRs) were synthesized via a wet chemical solution process at low temperature in short refluxing time. The structural and morphological properties of the obtained products were characterized by x-ray diffraction pattern and field emission scanning electron microscopy. The photocatalytic degradation process significantly shows enhanced activity of ZnO-HNRs under UV-Vis light in presence of rhodamine 6G dye (RhB). The effective concentration of ZnO-HNRs shows degradation process of RhB dye and was investigated via standard analytical techniques, optimized and validated by statistical analytical parameters. The statistical constraints give necessary information for establishing analytical procedures to ensure the quality and purity of the results. The absorption spectra were recorded at maximum absorbance ? max 470 nm, 520 nm, and 550 nm for ZnO-HNRs, RhB and ZnO-HNRs-RhB, respectively. Satisfactory data were obtained from UV-Vis spectroscopy, providing more reliable values against many factual variable factors such as concentration, volume, pH, time and temperature, etc.

  1. Statistical Parameters Effects on Photocatalytic Degradation of Rhodamine 6G Dye with Hexagonal Zinc Oxide Nanorods Synthesized via Solution Process

    NASA Astrophysics Data System (ADS)

    Wahab, Rizwan; Khan, Farheen

    2014-09-01

    Hexagonal-shaped zinc oxide nanorods (HNRs) were synthesized via a wet chemical solution process at low temperature in short refluxing time. The structural and morphological properties of the obtained products were characterized by x-ray diffraction pattern and field emission scanning electron microscopy. The photocatalytic degradation process significantly shows enhanced activity of ZnO-HNRs under UV-Vis light in presence of rhodamine 6G dye (RhB). The effective concentration of ZnO-HNRs shows degradation process of RhB dye and was investigated via standard analytical techniques, optimized and validated by statistical analytical parameters. The statistical constraints give necessary information for establishing analytical procedures to ensure the quality and purity of the results. The absorption spectra were recorded at maximum absorbance ? max 470 nm, 520 nm, and 550 nm for ZnO-HNRs, RhB and ZnO-HNRs-RhB, respectively. Satisfactory data were obtained from UV-Vis spectroscopy, providing more reliable values against many factual variable factors such as concentration, volume, pH, time and temperature, etc.

  2. Effects of dipeptidyl peptidase IV inhibitor sitagliptin on immunological parameters of lymphocytes in intact animals and animals with experimental autoimmune process.

    PubMed

    Robinson, M V; Mel'nikova, E V; Trufakin, V A

    2014-11-01

    The effects of dipeptidyl peptidase IV inhibitor sitagliptin on immunological parameters were studied in animals with experimental autoimmune process. The effects of the drug administered in preventive (before manifestation of autoimmune processes) and therapeutic (after manifestation of autoimmune process) modes were studied. PMID:25408522

  3. Prediction and quantifying parameter importance in simultaneous anaerobic sulfide and nitrate removal process using artificial neural network.

    PubMed

    Cai, Jing; Zheng, Ping; Qaisar, Mahmood; Luo, Tao

    2015-06-01

    The present investigation deals with the prediction of the performance of simultaneous anaerobic sulfide and nitrate removal in an upflow anaerobic sludge bed (UASB) reactor through an artificial neural network (ANN). Influent sulfide concentration, influent nitrate concentration, S/N mole ratio, pH, and hydraulic retention time (HRT) for 144 days' steady-state condition were the inputs of the model; whereas output parameters were sulfide removal percentage, nitrate removal percentage, sulfate production percentage, and nitrogen production percentage. The prediction performance was evaluated by calculating root mean square error (RMSE), mean absolute error (MAE), mean absolute relative error (MARE), and determination coefficient (R (2)) values. Generally, the ANN model exhibited good prediction of the simultaneous sulfide and nitrate removal process. The effect of five input parameters to the performance of the reactor was quantified and compared using the connection weights method, Garson's algorithm method, and partial derivatives (PaD) method. The results showed that HRT markedly affects the performance of the reactor. PMID:25523291

  4. Solid formulations by a nanocrystal approach: critical process parameters regarding scale-ability of nanocrystals for tableting applications.

    PubMed

    Tuomela, Annika; Laaksonen, Timo; Laru, Johanna; Antikainen, Osmo; Kiesvaara, Juha; Ilkka, Jukka; Oksala, Olli; Rönkkö, Seppo; Järvinen, Kristiina; Hirvonen, Jouni; Peltonen, Leena

    2015-05-15

    Nanocrystallization is among the foremost drug delivery platform approaches for the commercial development of poorly soluble drugs. There exists an urge to enable a universal shift of the production of the solid nanocrystal formulations from laboratory scale to industrially feasible scale. The success of any formulation development depends on its transferability to large scale manufacture. The objectives of the study were to increase the nanocrystallization batch size and to screen and optimize parameters for industrially feasible itraconazole (ITC) and indomethacin (IND) nanocrystal composition for tablet formulation. Thus, ITC and IND were transformed into nanocrystal suspensions, using an increased batch size of a wet milling process, freeze-dried, and further developed into both direct compression (DC) and granulated (G) tableting masses. According to the investigated powder and tablet properties (true density, flowability, dose uniformity, maximum upper punch force, crushing strength, dissolution and disintegration) and stability testings, it was clear that the amount of the nanocrystals in the solid tablet formulation is critical in order to fully utilize the benefits of the nanocrystals, i.e., fast dissolution, and to produce high-quality tablets. The DC designs of both the model drugs with compositions including 40% of freeze-dried nanocrystalline drug powder outperformed the corresponding granulated tablets in all parameters after the stability surveillance. PMID:25746735

  5. Effect of alloying elements and processing parameters on the Portevin-Le Chatelier effect of Al-Mg alloys

    NASA Astrophysics Data System (ADS)

    Ma, Peng-cheng; Zhang, Di; Zhuang, Lin-zhong; Zhang, Ji-shan

    2015-02-01

    The effects of alloying elements and processing parameters on the mechanical properties and Portevin-Le Chatelier effect of Al-Mg alloys developed for inner auto body sheets were investigated in detail. Tensile testing was performed in various Zn and Mg contents under different annealing and cold-rolling conditions. In the results, the stress drop and reloading time of serrations increase with increasing plastic strain and exhibit a common linear relationship. The increase rates of stress drop and reloading time increase with increasing Mg or Zn content. The alloys with a greater intensity of serrated yielding generally exhibit a greater elongation. The stress drop and reloading time of serrations decrease with increasing grain size in the case of the annealed samples. The cold-rolled sample exhibits the most severe serration because it initially contains a large number of grain boundaries and dislocations.

  6. Effect of inducers and process parameters on laccase production by Streptomyces psammoticus and its application in dye decolourization.

    PubMed

    Niladevi, K N; Prema, P

    2008-07-01

    The process parameters influencing the production of extracellular laccases by Streptomyces psammoticus MTCC 7334 were optimized in submerged fermentation. Coffee pulp and yeast extract were the best substrate and nitrogen source respectively for laccase production by this strain. The optimization studies revealed that the laccase yield was maximum at pH 7.5 and temperature 32 degrees C. Salinity of the medium was also observed to be influencing the enzyme production. An agitation rate of 175 rpm and 15% inoculum were the other optimized conditions for maximum laccase yield (5.9 U/mL). Pyrogallol and para-anisidine proved to be the best inducers for laccase production by this strain and the enzyme yield was enhanced by 50% with these inducers. S. psammoticus was able to decolourize various industrial dyes at different rates and 80% decolourization of Remazol Brilliant Blue R (RBBR) was observed after 10 days of incubation in dye based medium. PMID:17765539

  7. 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.

  8. Processing and properties of powder metallurgy Ni/sub 3/Al-Cr-Zr-B for use in oxidizing environments

    SciTech Connect

    Sikka, V.K.; Liu, C.T.; Loria, E.A.

    1986-10-01

    The addition of Cr to B-doped Ni/sub 3/Al in small ingots used for alloy development alleviates dynamic embrittlement, as exemplified by low tensile elongation and intergranular fracture, upon testing in air at 600/sup 0/C. Powder metallurgy (PM) technology is advantageous to properties due to improved microstructure from rapid solidification, and its effectiveness was studied in the up-scale production of four heats of this intermetallic compound with 8 Cr, 0.8 or 1.8 Zr, and 0.02 B (wt %). Sheet derived from a cold-rolling and annealing sequence on extruded product had a satisfactory level of ductility in tensile tests conducted in air within the critical 400 to 800/sup 0/C range. The processing parameters for hot workability of the PM product were established via a number of different strain rate tensils tests in air at temperatures up to 1100/sup 0/C. Superplastic behavior presented the opportunity for fabrication of a forged shape by hot isothermal forging. Preliminary forging of cylinders cut from the extruded bars revealed no peripheral cracking in 60% compression tests at strain rates of 0.1 to 0.5/min at 1100/sup 0/C. Successful isothermal forging of a prototype turbine disk directly from extruded bar stock in a closed die at 1100/sup 0/C and strain rate of 0.5/min was demonstrated, and the microstructure and mechanical properties were at least equal to those of PM sheet and bar products. 12 figs., 5 tabs.

  9. 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.

  10. The influence of melting process and parameters on the structure and homogeneity of titanium-tantalum alloys

    SciTech Connect

    Dunn, P.S.; Korzewka, D.; Garcia, F.; Damkroger, B.K.; Van Den Avyle, J.A.; Tissot, R.G.

    1995-12-31

    Alloys of titanium with refractory metals are attractive materials for applications requiring high temperature strength and corrosion resistance. However, the widely different characteristics of the component elements have made it difficult to produce sound, compositionally homogeneous ingots using traditional melting techniques. This is particularly critical because the compositional ranges spanned by the micro- and macrosegregation in theses systems can easily encompass a number of microconstituents which are detrimental to mechanical properties. This paper presents results of a study of plasma (PAM) and vacuum-arc (VAR) melting of a 60 wt% tantalum, 40 wt% titanium binary alloy. The structural and compositional homogeneity of both PAM consolidated + PAM remelted, and PAM consolidated + VAR remelted ingots were characterized and compared using optical and electron microscopy and x-ray fluorescence microanalysis. Additionally, the effect of melting parameter, including melt rate and magnetic stirring, was studied. Results indicate that PAM remelting achieves more complete dissolution of lie starting electrode, due to greater local superheat, than does VAR remelting. PAM remelting also produces a finer as-solidified grain structure, due to the smaller molten pool and lower local solidification times. Conversely, VAR remelting produces an ingot with a more uniform macrostructure, due to the more stable movement of the solidification interface and more uniform material feed rate. Based on these results, a three-step process of PAM consolidation, followed by a PAM intermediate melt and a VAR final melt, has been selected for further development of the alloy and processing sequence.

  11. The influence of melting processes and parameters on the structure and homogeneity of titanium-tantalum alloys

    SciTech Connect

    Dunn, P.S.; Korzekwa, D.; Garcia, F.; Damkroger, B.K.; Avyle, J.A. Van Den; Tissot, R.G.

    1996-06-01

    Alloys of titanium with refractory metals are attractive materials for applications requiring high temperature strength and corrosion resistance. However, the widely different characteristics of the component elements have made it difficult to produce sound, compositionally homogeneous ingots using traditional melting techniques. This is particularly critical because the compositional ranges spanned by the micro- and macrosegregation in theses systems can easily encompass a number of microconstituents which are detrimental to mechanical properties. This paper presents the results of a study of plasma (PAM) and vacuum-arc (VAR) melting of a 60 wt% tantalum, 40 wt% titanium binary alloy. The structural and compositional homogeneity of PAM consolidated +PAM remelted, and PAM consolidated +VAR remelted ingots were characterized and compared using optical and electron microscopy and x-ray fluorescence microanalysis. Additionally, the effect of melting parameter, including melt rate and magnetic stirring, was studied. The results indicated the PAM remelting achieves more complete dissolution of the starting electrode, due to greater local superheat, than does VAR remelting. PAM remelting also produces a finer as solidified grain structure, due to the smaller molten pool and lower local solidification times. Conversely, VAR remelting produces an ingot with a more uniform macrostructure, due to the more stable movement of the solidification interface and more uniform material feed rate. Based on these results, a three-step process of PAM consolidation, followed by a PAM intermediate melt and a VAR final melt, has been selected for further development of the alloy and processing sequence.

  12. MnO2/CeO2 for catalytic ultrasonic decolorization of methyl orange: Process parameters and mechanisms.

    PubMed

    Zhao, He; Zhang, Guangming; Chong, Shan; Zhang, Nan; Liu, Yucai

    2015-11-01

    MnO2/CeO2 catalyst was prepared and characterized by means of Brunauer-Emmet-Teller (BET) method, X-ray diffraction (XRD) and scanning electron microscope (SEM). The characterization showed that MnO2/CeO2 had big specific surface area and MnO2 was dispersed homogeneously on the surface of CeO2. Excellent degradation efficiency of methyl orange was achieved by MnO2/CeO2 catalytic ultrasonic process. Operating parameters were studied and optimized. The optimal conditions were 10 min of ultrasonic irradiation, 1.0 g/L of catalyst dose, 2.6 of pH value and 1.3 W/ml of ultrasonic density. Under the optimal conditions, nearly 90% of methyl orange was removed. The mechanism of methyl orange degradation was further studied. The decolorization mechanism in the ultrasound-MnO2/CeO2 system was quite different with that in the ultrasound-MnO2 system. Effects of manganese and cerium in catalytic ultrasonic process were clarified. Manganese ions in solution contributed to generating hydroxyl free radical. MnO2/CeO2 catalyst strengthened the oxidation ability of ultrasound and realized complete decolorization of methyl orange. PMID:26186869

  13. On the role of processing parameters in producing Cu/SiC metal matrix composites via friction stir processing: Investigating microstructure, microhardness, wear and tensile behavior

    SciTech Connect

    Barmouz, Mohsen; Besharati Givi, Mohammad Kazem; Seyfi, Javad

    2011-01-15

    The main aim of this study is to produce copper reinforced metal matrix composite (MMC) layers using micron sized SiC particles via friction stir processing (FSP) in order to enhance surface mechanical properties. Microstructural evaluation using optical microscopy (OM) and scanning electron microscopy (SEM) indicated that an increase in traverse speed and a decrease in rotational speed cause a reduction in the grain size of stir zone (SZ) for the specimens friction stir processed (FSPed) without SiC particles. With the aim of determining the optimum processing parameters, the effect of traverse speed as the main processing variable on microstructure and microhardness of MMC layers was investigated. Higher traverse speeds resulted in poor dispersion of SiC particles and consequently reduced the microhardness values of MMC layers. It was found that upon addition of SiC particles, wear properties were improved. This behavior was further supported by SEM images of wear surfaces. Results demonstrated that the microcomposite produced by FSP exhibited enhanced wear resistance and higher average friction coefficient in comparison with pure copper. Tensile properties and fracture characteristics of the specimens FSPed with and without SiC particles and pure copper were also evaluated. According to the results, the MMC layer produced by FSP showed lower strength and elongation than pure copper while a remarkable elongation was observed for FSPed specimen without SiC particles. Research Highlights: {yields} Decrease in traverse speed leads to good dispersion of SiC particles in composites. {yields} No distinct TMAZ in side regions of SZ of FSPed specimens with SiC particles. {yields} Microhardness of FSPed specimens with SiC particles shows a remarkable increase. {yields} Reinforcement of Cu with SiC particles improves wear and friction behavior of surface. {yields} A weak bonding in tensile due to probable agglomeration for SiC containing samples.

  14. Influence of process parameters on the content of biomimetic calcium phosphate coating on titanium: a Taguchi analysis.

    PubMed

    Thammarakcharoen, Faungchat; Suvannapruk, Waraporn; Suwanprateeb, Jintamai

    2014-10-01

    In this study, a statistical design of experimental methodology based on Taguchi orthogonal design has been used to study the effect of various processing parameters on the amount of calcium phosphate coating produced by such technique. Seven control factors with three levels each including sodium hydroxide concentration, pretreatment temperature, pretreatment time, cleaning method, coating time, coating temperature and surface area to solution volume ratio were studied. X-ray diffraction revealed that all the coatings consisted of the mixture of octacalcium phosphate (OCP) and hydroxyapatite (HA) and the presence of each phase depended on the process conditions used. Various content and size (-1-100 ?m) of isolated spheroid particles with nanosized plate-like morphology deposited on the titanium surface or a continuous layer of plate-like nanocrystals having the plate thickness in the range of -100-300 nm and the plate width in the range of 3-8 ?m were formed depending on the process conditions employed. The optimum condition of using sodium hydroxide concentration of 1 M, pretreatment temperature of 70 degrees C, pretreatment time of 24 h, cleaning by ultrasonic, coating time of 6 h, coating temperature of 50 degrees C and surface area to solution volume ratio of 32.74 for producing the greatest amount of the coating formed on the titanium surface was predicted and validated. In addition, coating temperature was found to be the dominant factor with the greatest contribution to the coating formation while coating time and cleaning method were significant factors. Other factors had negligible effects on the coating performance. PMID:25942836

  15. Effects of processing conditions on structural and functional parameters of whipped dairy emulsions containing various fatty acid compositions.

    PubMed

    Bazmi, A; Relkin, P

    2009-08-01

    An understanding of the effects of processing parameters can be applied to formulate emulsions with higher unsaturated fatty acid content. Emulsions using the typical ice cream formulation were produced by anhydrous milk fat alone or in a mixture with either olein or stearin at a 2:1 weight ratio. Effects of both pasteurization holding time (40 or 120 s at 80 degrees C) and aging time (ranging from 2 to 24 h) on the structural and whipping properties of the emulsions were studied. Effects of these processing conditions on emulsion structural characteristics were determined using laser light-scattering measurements, rheological properties, microscopic observations, and image analyses of the whipped emulsions. Furthermore, foaming properties of these emulsions were compared and discussed with regard to effects of both processing and composition on properties of the emulsions, such as thixotropy and sensitivity to shearing. We observed changes in fat globules when different pasteurization holding times were applied, but no changes in either apparent viscosity values or sensitivity to shearing were traceable. However, enrichment of milk fat with the olein fraction increased the whipping ability of the emulsions, as evaluated in terms of overrun and the homogeneity of air bubbles, whatever the aging time. The lowest monodispersity of air bubbles was observed in the formulation rich in stearin. After 24 h of aging, this formulation showed the same overrun as the emulsion made with anhydrous milk fat. Increasing the aging time decreased the overrun by approximately 30%, and increasing the pasteurization holding times decreased it by approximately 20%. In general, in our conditions, increasing the aging time and unsaturated fatty acid content reduced changes in the dynamic rheological and structural properties observed just after production of the emulsions, whatever the pasteurization holding time or fat composition applied. PMID:19620637

  16. Modeling of a short-path distillation process to remove persistent organic pollutants in fish oil based on process parameters and quantitative structure properties relationships.

    PubMed

    Oterhals, Age; Kvamme, Bjørn; Berntssen, Marc H G

    2010-06-01

    A factorial experimental design based on temperature, feed rate and addition of "working fluid" (WF; fatty acid ethyl esters) was used to model a short-path distillation process applied for removal of persistent organic pollutants (POPs) in fish oil. Decontamination effect was assessed by measuring the level of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs) and polybrominated diphenylethers (PBDEs). The average reduction in chemical concentration of the individual PCDD, PCDF, DL-PCB and PBDE congeners was linearly dependent on the number of chlorine or bromine substitutions within each homologue group. DL-PCB and PBDE congeners could also be separated based on ortho-substitution. The quantitative structure properties relationships (QSPR) were combined with process parameters to establish response surface models for each homologue congener group based on partial least squares regression (PLSR). Cross validated predictive ability of the models was in the 4-9% range. Generally high temperature, low feed rate and WF addition improved the decontamination efficiency. The WHO-PCDD/F-PCB-TEQ level could be reduced by up to 98% based on the best experimental settings with residual concentration considerably below present maximum permitted levels in European food and feed legislations. PMID:20444484

  17. Application of quality by design approach to optimize process and formulation parameters of rizatriptan loaded chitosan nanoparticles

    PubMed Central

    Shirsat, Ajinath Eknath; Chitlange, Sohan S.

    2015-01-01

    The purpose of present study was to optimize rizatriptan (RZT) chitosan (CS) nanoparticles using ionic gelation method by application of quality by design (QbD) approach. Based on risk assessment, effect of three variables, that is CS %, tripolyphosphate % and stirring speed were studied on critical quality attributes (CQAs); particle size and entrapment efficiency. Central composite design (CCD) was implemented for design of experimentation with 20 runs. RZT CS nanoparticles were characterized for particle size, polydispersity index, entrapment efficiency, in-vitro release study, differential scanning calorimetric, X-ray diffraction, scanning electron microscopy (SEM). Based on QbD approach, design space (DS) was optimized with a combination of selected variables with entrapment efficiency > 50% w/w and a particle size between 400 and 600 nm. Validation of model was performed with 3 representative formulations from DS for which standard error of ? 0.70–3.29 was observed between experimental and predicted values. In-vitro drug release followed initial burst release 20.26 ± 2.34% in 3–4 h with sustained drug release of 98.43 ± 2.45% in 60 h. Lower magnitude of standard error for CQAs confirms the validation of selected CCD model for optimization of RZT CS nanoparticles. In-vitro drug release followed dual mechanism via, diffusion and polymer erosion. RZT CS nanoparticles were prepared successfully using QbD approach with the understanding of the high risk process and formulation parameters involved and optimized DS with a multifactorial combination of critical parameters to obtain predetermined RZT loaded CS nanoparticle specifications. PMID:26317071

  18. 78 FR 8587 - Heraeus Kulzer, LLC., Including On-Site Leased Workers from People Link Staffing, Forge Staffing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-06

    ...People Link Staffing, Forge Staffing, Career Transitions and Talent Source; South...company shows that workers leased from Career Transitions and Talent Source were employed...certification to include workers leased from Career Transitions and Talent Source...

  19. Snow Parameter Caused Uncertainty of Predicted Snow Metamorphism Processes Report on the Research Performed during the REU Program at the University of Alaska Fairbanks,

    E-print Network

    Moelders, Nicole

    Snow Parameter Caused Uncertainty of Predicted Snow Metamorphism Processes Report on the Research (advisor) 2006 #12;2 Abstract Simulated snow metamorphism processes, snow fluxes and snow state variables limitations of the hydro-thermodynamic soil-vegetation scheme's snow model that are due to stochastic errors

  20. Effect of green Spanish-style processing (Manzanilla and Hojiblanca) on the quality parameters and fatty acid and triacylglycerol compositions of olive fat.

    PubMed

    López-López, Antonio; Cortés-Delgado, Amparo; Garrido-Fernández, Antonio

    2015-12-01

    This work studies the effect of processing Manzanilla and Hojiblanca olives as green Spanish-style on the quality parameters and fatty acid and triacylglycerol compositions of their oils. Lye treatment reduced the values of most quality parameters while fermentation/packaging increased acidity, K232 and K270. Processing did not cause any systematic effect on fatty acids (FA), triacylglycerols or nutritional fat subclasses but significant differences between cultivars were observed. Principal component analysis (PCA) confirmed that most of the variation among oil characteristics was due to cultivars and only a limited proportion (?22% and ?14% variance for FA and triacylglycerols, respectively) to processing. Furthermore, the levels of the quality parameters and fatty acids with restrictions in the legislation were below the limits established in the Commission Implementing Regulation (EU) 1348/2013 for extra virgin olive oil (EVOO), except for C18:3n-3 in Hojiblanca. Therefore, the fat of processed olives was compatible with EVOO. PMID:26041161