Dynamic Multiaxial Response of a Hot-Pressed Aluminum Nitride

Science.gov (United States)

2012-01-05

Hutchinson, Adv. Appl . Mech. 29 (1992). [34] H. Ming-Yuan, J.W. Hutchinson, Int. J. Solids Struct. 25 (1989) 1053. [35] J. Salem , L. Ghosn, Int. J...Dynamic Multiaxial Response of a Hot- Pressed Aluminum Nitride by Guangli Hu, C. Q. Chen, K. T. Ramesh, and J. W. McCauley ARL-RP-0487...Laboratory Aberdeen Proving Ground, MD 21005-5066 ARL-RP-0487 June 2014 Dynamic Multiaxial Response of a Hot- Pressed Aluminum Nitride

Hot-pressing steatite bodies; Obtencion de eseatita por prensado en caliente

Energy Technology Data Exchange (ETDEWEB)

Aparicio Arroyo, E

1967-07-01

Requirements for some special nuclear engineering ceramic shapes are: big size, impervious, dimensional accuracy and good mechanical and dielectric properties. Limitations of te conventional methods and advantages of te hot pressing techniques for the manufacturing of these shapes are discussed. Hot pressing characteristics of a certain steatite powder are studied. Occurrence of an optimum densification temperature just above the tale decomposition range is found. Experimental data show that the height/diameter ratio of the specimen has no effect on the sintering conditions. Increasing darkness from the graphite mould is detected above the optimum temperature. The hot-pressed steatite is compared with a fired dry-pressed sample of the same composition. (Author) 13 refs.

Strength-ductility relationships in intermediate purity hot-pressed beryllium

International Nuclear Information System (INIS)

Stonehouse, A.J.; Bielawski, C.A.; Paine, R.M.

1977-01-01

The strength of vacuum hot-pressed, intermediate purity beryllium may be substantially increased without sacrifice of the strain capacity of the present grade (S-65) through decrease in the average grain size. Tensile strength of 517 MPa, 0.2% offset yield strength of 414 MPa with minimum 3% tensile elongation in all test directions could be commercially achieved. The tangent modulus of such material is quite attractive and suffers only about 10% degradation from room temperature to 260 0 C. The tangent modulus is dramatically enhanced by the presence of a yield point. The ductility of the materials studied did not appear to be affected by the BeO content across the range of 0.5 to 2.0% using nominal -44 to -15 μm powder particle sizes. All fine-grained pressings exhibited yield points in the as-pressed condition. Either full-density or sub-density hot-pressed billets given a hot isostatic pressing treatment without the use of cans showed only slight yield points after the HIP treatment with essentially the same strength and ductility factors as in the pressed condition. A plot of grain size vs yield strength in the as-pressed condition projects to an intercept with the fracture strength line at about 3 μm grain size. A similar plot after the HIP treatment shows a yield strength line parallel to the fracture strength line with no projected intercept predicting a completely brittle material. (author)

Microstructural analysis of hot press formed 22MnB5 steel

Science.gov (United States)

Aziz, Nuraini; Aqida, Syarifah Nur; Ismail, Izwan

2017-10-01

This paper presents a microstructural study on hot press formed 22MnB5 steel for enhanced mechanical properties. Hot press forming process consists of simultaneous forming and quenching of heated blank. The 22MnB5 steel was processed at three different parameter settings: quenching time, water temperature and water flow rate. 22MnB5 was processed using 33 full factorial design of experiment (DOE). The full factorial DOE was designed using three factors of quenching time, water temperature and water flow rate at three levels. The factors level were quenching time range of 5 - 11 s, water temperature; 5 - 27°C and water flow rate; 20 - 40 L/min. The as-received and hot press forming processed steel was characterised for metallographic study and martensitic structure area percentage using JEOL Field Emission Scanning Electron Microscopic (FESEM). From the experimental finding, the hot press formed 22MnB5 steel consisted of 50 to 84% martensitic structure area. The minimum quenching time of 8 seconds was required to obtain formed sample with high percentage of martensite. These findings contribute to initial design of processing parameters in hot press forming of 22MnB5 steel blanks for automotive component.

Factors influencing the creep strength of hot pressed beryllium

International Nuclear Information System (INIS)

Webster, D.; Crooks, D.D.

1975-01-01

The parameters controlling the creep strength of hot pressed beryllium block have been determined. Creep strength was improved by a high initial dislocation density, a coarse grain size, and a low impurity content. The impurities most detrimental to creep strength were found to be aluminum, magnesium, and silicon. A uniform distribution of BeO was found to give creep strength which was inferior to a grain boundary distribution. The creep strength of very high purity, hot isostatically pressed beryllium was found to compare favorably with that of other more commonly used high temperature metals

Atlas of hot isostatic beryllium powder pressing diagrams

International Nuclear Information System (INIS)

Stoev, P.I.; Papirov, I.I.; Tikhinskij, G.F.; Vasil'ev, A.A.

1995-01-01

Diagrams of hot isotopic pressing (HIP) of beryllium powder with different grain size in a wide range of pressing parameters are built by mathematical modeling methods. The HIP diagrams presented are divided into 3 groups: parametric dependencies D=f(P,T); technological HIP diagrams; compacting mechanisms. The created data bank permits to optimise beryllium powder HIP with changing parameters. 4 refs., 23 figs

Hot and cold pressing of (La,Ce)PO4-based nuclear waste forms

International Nuclear Information System (INIS)

Floran, R.J.; Rappaz, M.; Abraham, M.M.; Boatner, L.A.

1981-01-01

Synthetic analogs of the mineral monazite [(Ce,La,Ca,Th,U)(P,Si)O 4 ] are promising host phases for the isolation of actinide wastes. In the present investigation, the optimal conditions necessary to form high-density, simulated waste pellets from calcined LaPO 4 and CePO 4 powders have been examined. Pellets that are close to the theoretical density are necessary in order to minimize porosity and hence potential avenues along which fluid/waste interactions can take place. Calcined powders prepared by a urea precipitation process were cold pressed and hot pressed under a range of controlled conditions to form coherent, cylindrical pellets. Changes in density were examined as a function of pressure, temperature and duration of sintering. For cold-pressed pellets, a significant increase in density occurs during sintering between 1000 0 C and 1100 0 C. This increase is correlated with substantial grain coarsening of the pellet microstructure. A comparison of cold and hot pressing techniques suggests that, only after sintering, does the density of cold-pressed pellets approach (but not equal) that of the hot-pressed pellets. Densities >90% of the theoretical value of 5.11 g/cm 3 are easily attainable by hot pressing without sintering. The significance of density differences on pellet stability will be investigated in future leaching studies. The apparent advantages of the higher densities achieved by hot pressing must be weighed against the increased technological/engineering complexities involved when working at sustained high temperatures in a remote environment. Thus the cold pressing technique may ultimately prove more practical for large-scale commercial operations

Graphite and boron carbide composites made by hot-pressing

International Nuclear Information System (INIS)

Miyazaki, K.; Hagio, T.; Kobayashi, K.

1981-01-01

Composites consisting of graphite and boron carbide were made by hot-pressing mixed powders of coke carbon and boron carbide. The change of relative density, mechanical strength and electrical resistivity of the composites and the X-ray parameters of coke carbon were investigated with increase of boron carbide content and hot-pressing temperature. From these experiments, it was found that boron carbide powder has a remarkable effect on sintering and graphitization of coke carbon powder above the hot-pressing temperature of 2000 0 C. At 2200 0 C, electrical resistivity of the composite and d(002) spacing of coke carbon once showed minimum values at about 5 to 10 wt% boron carbide and then increased. The strength of the composite increased with increase of boron carbide content. It was considered that some boron from boron carbide began to diffuse substitutionally into the graphite structure above 2000 0 C and densification and graphitization were promoted with the diffusion of boron. Improvements could be made to the mechanical strength, density, oxidation resistance and manufacturing methods by comparing with the properties and processes of conventional graphites. (author)

Ultra-low thermal conductivities of hot-pressed attapulgite and its potential as thermal insulation material

Energy Technology Data Exchange (ETDEWEB)

Liu, Yuan; Ren, Zhifeng, E-mail: bohr123@163.com, E-mail: zren@uh.edu [Department of Physics and TcSUH, University of Houston, Houston, Texas 77204 (United States); Wang, Xiuzhang [Department of Physics and TcSUH, University of Houston, Houston, Texas 77204 (United States); Hubei Key Laboratory of Pollutant Analysis and Reuse Technology and School of Physics and Electronic Science, Hubei Normal University, Huangshi, Hubei 435002 (China); Wang, Yumei [Department of Physics and TcSUH, University of Houston, Houston, Texas 77204 (United States); Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Tang, Zhongjia; Makarenko, Tatyana; Guloy, Arnold [Department of Chemistry, University of Houston, Houston, Texas 77204 (United States); Zhang, Qinyong, E-mail: bohr123@163.com, E-mail: zren@uh.edu [Center for Advanced Materials and Energy, Xihua University, Chengdu, Sichuan 610039 (China)

2016-03-07

In the past, there have been very few reports on thermal properties of attapulgite which is a widely used clay mineral. In this work, we report on extremely low thermal conductivities in attapulgite samples synthesized by hot-pressing. Attapulgite powder was hot-pressed at different temperatures into bulk samples, and a systematic study was conducted on the microstructures and thermal properties. Differential scanning calorimetry analysis shows that hot-pressing induces a rapid dehydration of the attapulgite powders. X-ray diffraction data and scanning/transmission electron microscopy reveal that the hot-pressed attapulgite features high porosity and complex microstructures, including an amorphous phase. As a result, the hot-pressed attapulgite exhibits thermal conductivity less than 2.5 W m{sup −1} K{sup −1} up to 600 °C. For one sample with porosity of 45.7%, the thermal conductivity is as low as 0.34 W m{sup −1} K{sup −1} at 50 °C. This suggests the potential of hot-pressed attapulgite as a candidate for thermal barrier materials.

Densification of boron carbide at relatively low temperatures by hot pressing and hot isostatic pressing

International Nuclear Information System (INIS)

Telle, R.

1988-01-01

The poor sinterability of B 4 C limits its widespread application because both high temperatures and high pressures are required for a complete densification. Moreover, B 4 C suffers from a low strength and fracture toughness, possesses, however, a high potential because of its extreme hardness. Reaction hot pressing of B 4 C-WC-TiC-Si-Co mixtures resulting in B 4 C-TiB 2 -W 2 B 5 composites of high density exhibit remarkable mechanical properties. The influence of hot isostatic pressing (HIP) on the microstructure and the mechanical properties is investigated in cooperation with participants of the COST 503 activities and related to the strengthening and toughening mechanisms. Difficulties during densification by HIP arise from the evaporation of adsorbed volatiles as well as from the strong swelling of the powder compact due to the sintering reaction. Several HIP cycle designs were tested in order to prevent the bloating of the capsule and to control internal stresses due to the misfit of the thermal expansion of the entire phases. In comparison to single phase B 4 C ceramics, bending strength was improved to 1030 MPa, K Ic to 5.2 MPa/m, while hardness was comparable with HV1=38 GPa. Wear test were performed and related to the toughening mechanisms. (orig.) With 56 refs., 9 tabs., 64 figs

Progress in hot pressing

International Nuclear Information System (INIS)

Brodhag, C.; Thevenot, F.

1988-01-01

An experimental technique is described to study hot pressing of ceramics under conditions of controlled temperature and pressure during both the heating and final sintering stages. This method gives a better control of the final microstructure of the material. Transformation mechanisms can be studied during initial heating stage (impurity degasing, reaction, phase transformation, mechanical behavior of intergranular phase...) using computer control and graphical data representations. Some examples will be given for different systems studied in our laboratory: B (α, β, amorphous), B 12 O 2 (reaction of B + B 2 O 3 ), Si 3 N 4 ( + additives), TiN, Al 2 O 3 + AlON,ZrC

Hot pressing, strength, and fracture of calcium hexaboride

International Nuclear Information System (INIS)

Dutta, S.K.

1975-01-01

Fracture behavior and strength of hot-pressed CaB 6 were studied. The modulus of elasticity determined by attaching strain gages to the tensile surface of the bend bars to measure strain, was 55 +- 3 x 10 6 psi. The results are compared with values for other low density ceramic materials (B 4 C, SiB 6 , Be 4 B, AlB 12 ) in a table. The fracture mode was observed for both modulus of rupture and impact test specimens. Predominantly transgranular fracture, associated with distinct step cleavages is evident. Fracture origins were examined in an effort to understand the strength limiting features in hot-pressed CaB 6 specimens. Surface defects, large grain agglomerations, and isolated pore pockets were observed and varied from bar to bar; these were similar to those found in B 4 C. (U.S.)

Expanded Analysis of Hot Isostatic Pressed Iodine-Loaded Silver-Exchanged Mordenite

Energy Technology Data Exchange (ETDEWEB)

Jubin, R. T. [ORNL; Bruffey, S. H. [ORNL; Patton, K. K. [ORNL

2014-09-30

Reduced silver-exchanged mordenite (Ag0Z) is being evaluated as a potential material to control the release of radioactive iodine that is released during the reprocessing of used nuclear fuel into the plant off-gas streams. The purpose of this study was to determine if hot pressing could directly convert this iodine loaded sorbent into a waste form suitable for long-term disposition. The minimal pretreatment required for production of pressed pellets makes hot pressing a technically and economically desirable process. Initial scoping studies utilized hot uniaxial pressing (HUPing) to prepare samples of non-iodine-loaded reduced silver exchanged mordenite (Ag0Z). The resulting samples were very fragile due to the low pressure (~ 28 MPa) used. It was recommended that hot isostatic pressing (HIPing), performed at higher temperatures and pressures, be investigated. HIPing was carried out in two phases, with a third and final phase currently underway. Phase I evaluated the effects of pressure and temperature conditions on the manufacture of a pressed sample. The base material was an engineered form of silver zeolite. Six samples of Ag0Z and two samples of I-Ag0Z were pressed. It was found that HIPing produced a pressed pellet of high density. Analysis of each pressed pellet by scanning electron microscopy-energy dispersive spectrophotometry (SEM-EDS) and X-ray diffraction (XRD) demonstrated that under the conditions used for pressing, the majority of the material transforms into an amorphous structure. The only crystalline phase observed in the pressed Ag0Z material was SiO2. For the samples loaded with iodine (I-Ag0Z) iodine was present as AgI clusters at low temperatures, and transformed into AgIO4 at high temperatures. Surface mapping and EDS demonstrate segregation between silver iodide phases and silicon dioxide phases. Based on the results of the Phase I study, an expanded test matrix was developed to examine the effects of multiple source materials, compositional

Safe trapping of cesium into pollucite structure by hot-pressing method

International Nuclear Information System (INIS)

Omerašević, Mia; Matović, Ljiljana; Ružić, Jovana; Golubović, Željko; Jovanović, Uroš; Mentus, Slavko; Dondur, Vera

2016-01-01

A simple one-step method with direct thermal conversion at lower temperatures for preparing a stabile Cs-aluminsilicate phase, known as pollucite, is presented. Cs-exchanged form of Na, Ca-LTA type of zeolite (Cs-LTA) was pressureless sintered and hot pressed at certain temperatures in order to obtain pollucite. XRD and FTIR analysis were used to study structural changes of Cs-LTA before and after thermal treatments. Pressureless sintered sample recrystallized into pollucite phase after heat treatment at 1000 °C (3 h) (PLS1000) and hot pressed sample at 750 °C (3 h) using pressure of 35 MPa (HP750), indicating reduced temperature of 250°. SEM micrographs confirmed that HP750 has higher density than PLS1000 which leads to higher value of compressive strength. The HP750 showed better resistance to Cs leaching than the PLS1000. Base on these results one can conclude that hot pressing is the promising method for the permanent disposal of Cs radionuclides. - Highlights: • Na, Ca-LTA zeolite showed high affinity for Cs ions. • Pollucite phase was obtained using hot pressing at temperature as low as ​750 °C. • HP750 shows better mechanical and morphological properties than PLS1000. • HP750 has lower leaching rate of Cs ions than PLS1000.

The fabrication of ZnO nanowire field-effect transistors combining dielectrophoresis and hot-pressing

International Nuclear Information System (INIS)

Chang, Y-K; Chau-N H, Franklin

2009-01-01

Zinc oxide nanowire field-effect transistors (NW-FETs) were fabricated combining the dielectrophoresis (DEP) and the hot-pressing methods. DEP was used to position both ends of the nanowires on top of the source and the drain electrodes, respectively. Hot-pressing of nanowires on the electrodes was then employed to ensure good contacts between the nanowires and the electrodes. The good device performance achieved with our method of fabrication indicates that DEP combined with hot-pressing has the potential to be applied to the fabrication of flexible electronics on a roll-to-roll basis.

Effect of hot isostatic pressing on the properties of sintered alpha silicon carbide

Science.gov (United States)

Watson, G. K.; Moore, T. J.; Millard, M. L.

1985-01-01

Two lots of alpha silicon carbide were isostatically hot-pressed under 138 MPa for 2 h in Ar at temperatures up to 2200 C. Nearly theoretically dense specimens resulted. Hot isostatic pressing increased both room-temperature strength and 1200 C strength, and resulted in improved reliability. One lot of material which was pressed at 2200 C showed increases of about 20 percent in room-temperature strength and about 50 percent in 1200 C flexural strength; the Weibull modulus improved about 100 percent.

An overview of high thermal conductive hot press forming die material development

Directory of Open Access Journals (Sweden)

A.R. Zulhishamuddin

2015-12-01

Full Text Available Most of the automotive industries are using high strength steel components, which are produced via hot press forming process. This process requires die material with high thermal conductivity that increases cooling rate during simultaneous quenching and forming stage. Due to the benefit of high quenching rate, thermal conductive die materials were produced by adding carbide former elements. This paper presents an overview of the modification of alloying elements in tool steel for high thermal conductivity properties by transition metal elements addition. Different types of manufacturing processes involved in producing high thermal conductive materials were discussed. Methods reported were powder metallurgy hot press, direct metal deposition, selective laser melting, direct metal laser sintering and spray forming. Elements likes manganese, nickel, molybdenum, tungsten and chromium were proven to increase thermal conductivity properties. Thermal conductivity properties resulted from carbide network presence in the steel microstructure. To develop feasible and low cost hot press forming die material, casting of Fe-based alloy with carbide former composition can be an option. Current thermal conductivity properties of hot press forming die material range between 25 and 66 W/m.K. The wide range of thermal conductivity varies the mechanical properties of the resulting components and lifetime of HPF dies.

Hot pressing of nanocrystalline tantalum using high frequency induction heating and pulse plasma sintering

Science.gov (United States)

Jakubowicz, J.; Adamek, G.; Sopata, M.; Koper, J. K.; Siwak, P.

2017-12-01

The paper presents the results of nanocrystalline powder tantalum consolidation using hot pressing. The authors used two different heating techniques during hot pressing: high-frequency induction heating (HFIH) and pulse plasma sintering (PPS). A comparison of the structure, microstructure, mechanical properties and corrosion resistance of the bulk nanocrystalline tantalum obtained in both techniques was performed. The nanocrystalline powder was made to start from the microcrystalline one using the high-energy ball milling process. The nanocrystalline powder was hot-pressed at 1000 °C, whereas, for comparison, the microcrystalline powder was hot pressed up to 1500 °C for proper consolidation. The authors found that during hot pressing, the powder partially reacts with the graphite die covered by boron nitride, which facilitated punches and powder displacement in the die during densification. Tantalum carbide and boride in the nanocrystalline material was found, which can improve the mechanical properties. The hardness of the HFIH and PPS nanocrystalline tantalum was as high as 625 and 615 HV, respectively. The microstructure was more uniform in the PPS nanomaterial. The corrosion resistance in both cases deteriorated, in comparison to the microcrystalline material, while the PPS material corrosion resistance was slightly better than that of the HFIH one.

Preparation and microstructure of hot-pressed YIG

International Nuclear Information System (INIS)

Abdul Halim Shaari; Mansor Hashim; Sidek Haji Abd Aziz

1992-01-01

Bulk magnetic ceramics such as yttrium-iron-garnet (YIG) and nickel-zinc ferrite were prepared by the conventional-firing and hot-press techniques. Pre-sintering and sintering, both in air, were carried out at temperature ≥ 1200 0 C. Initial density and microstructural measurements show that the high density samples with uniform grain size can be readily achieved by hot-pressing. The well-defined microstructures, the high density attained. The agreement of saturation magnetization 4πMs values and the high resistivities indicated that the optimized preparation conditions for conventional firing yielded yttrium-iron-garnet of good quality. Quenched and isochronally annealed, the YIG samples were also found to retain their room-temperature saturation-magnetization and resonance linewidth values after any single heat treatment. However, the electrical resistivity and the effective linewidth clearly exhibited isochronal recovery. A possible model to explain this behaviour and its implications on microwave applications are discussed. Ferrites of the type MFe 2 O 4 where M=Mg, Mn, Co, Fe, Cu, Zn and Cd and of the type Ni1-2xSnxFe 2 O4 have also been prepared and their properties are being studied

Immobilisation of 137Cs and 90Sr in hot-pressed clinoptilolite

International Nuclear Information System (INIS)

Briggs, A.; Jones, D.V.C.; Cole, G.B.; Valentine, T.M.; Preston, R.F.; Hawes, R.W.M.; Fones, M.D.

1984-07-01

It is shown that clinoptilolites from Nevada and Mudhills, California, can be vitrified by hot-pressing at 1000 to 1050 deg C for 30 min under 23 MPa pressure in graphite dies, or for 10 min under 3.5 MPa pressure in stainless steel bellows-shaped containers. Activity measurements before and after hot-pressing show that the radionuclides 137 Cs and 90 Sr are retained almost completely during the process. The hot-pressed material is shown to be extremely resistant to leaching of the nuclides, either in Soxhlet or long-term static leach tests. Gamma-irradiation increases their leachability; that of 90 Sr more than that of 137 Cs, but even so, the leach rates of both remain very low. X-ray diffraction spectra taken before and after heat-treatment for 10 days at temperatures up to 1000 deg C show no deleterious effects, and hydrothermal treatments at temperatures up to 90 deg C for 100 days, even in the presence of sodium ions in solution, are shown not to cause any changes detectable by X-ray diffraction. (author)

Cold-pressed and hot-pressed rapeseed oil: The effects of roasting and seed moisture on the antioxi- dant activity, canolol, and tocopherol level.

Science.gov (United States)

Siger, Aleksander; Józefiak, Marta; Górnaś, Paweł

2017-01-01

The paper looks at the levels of canolol, tocopherols and antioxidant activity in cold-pressed and hot-pressed rapeseed oils produced from seeds of various moisture levels (5%, 7.5%, and 10%). The paper also considers the effects of seed roasting on the levels of these compounds. The material used for the tests was rapeseed cv. Adrianna. The quality of the oils obtained is determined using peroxide and acid values. The levels of canolol and tocopherols are analyzed using HPLC. The DPPH radical-scavenging activity method for oil samples and phenolic extract from oils was used. It has been demonstrated that the oils produced from rapeseeds with a 5% moisture content, and   in particular from cold-pressed oils, were characterized by the lowest peroxide values. Cold-pressed oils produced from rapeseeds with a 5% moisture content were characterized by higher levels of tocopherols and plastochromanol-8. In the case of hot-pressed oils, the highest levels of tocopherols were found in oils pro- duced from seeds with a 7.5% moisture content, and the greatest amount of PC-8 (more than 4 mg/100 g) was found in oils produced from seeds with a 10% moisture content. Hot-pressed oils have been shown to have higher levels of these compounds than cold-pressed oils. Both roasting and hot pressing led to an increase in the amount of canolol in the oils investigated. When analysing the antioxidant activity of the oils and phenolic extracts it was shown that phenolic compounds are responsible for approx. 10% of total antioxidant activity. Various levels of biologically active compounds were shown to be present in the rapeseed oil obtained from raw materials of a varying moisture content. The type of pressing process (cold-pressing or hot-pressing) and whether the seeds have undergone roasting has also been shown to affect the resulting oil and the level of native antioxidants it contains.

MICROSTRUCTURAL ANALYSIS OF HOT ISOSTATICALLY PRESSED AL-SIC

NARCIS (Netherlands)

Bronsveld, P.M.; Hosson, J.Th. De; Sargent, M.A.; Alsem, W.H.M.

1991-01-01

The difference between extruded and hot isostatically pressed (HIP) Al6061 both with a T6 final heat treatment and with a 30 wt.% SiC particulate reinforcement is one of densification. The higher density of the HIP material is not translated into a stronger material. The Mg2Si precipitation is

EFFECT OF CHEMICAL MODIFICATION AND HOT-PRESS DRYING ON POPLAR WOOD

Directory of Open Access Journals (Sweden)

Guo-Feng Wu

2010-11-01

Full Text Available Urea-formaldehyde prepolymer and hot-press drying were used to improve the properties of poplar wood. The wood was impregnated with the prepolymer using a pulse-dipping machine. The impregnated timbers were compressed and dried by a multilayer hot-press drying kiln. The drying rate was more rapid during the chemical modification and hot-press drying than conventional kiln-drying. In addition, the properties of timber were also enhanced obviously. When the compression rate was 28.6%, the basic density, oven dry density and air-dried density of modified wood improved 22%, 71%, and 70%, respectively. The bending strength and compressive strength parallel to grain increased 60% and 40%. The water uptake of treated wood was significantly decreased compared with the untreated wood. The FTIR analysis successfully showed that the intensity of hydroxyl and carbonyl absorption peaks decreased significantly, which was attributed to a reaction of the NHCH2OH of urea-formaldehyde prepolymer with the wood carboxyl (C=O and hydroxyl (-OH groups. The XRD results indicated that the degree of crystallinity increased from 35.09% to 36.91%. The morphologic models of chemical within wood were discovered by SEM.

ACTIVATED HOT PRESSING BEHAVIOR OF WC NANOPOWDERS

Directory of Open Access Journals (Sweden)

Edwin GEVORKYAN

2010-06-01

Full Text Available The questions of consolidation of nanopowders concerning hot compaction by pressing activated by electric current action are considered. Mechanisms of grain boundary creep-sliding which are sequentially prevalent in a forming of compacted structures under influence of temperature factor and in the presence of a direct electric heating are discussed. Structural-transformational sources and conditions of forming of high physical-mechanical properties of nanopowder refractory solid-state products are described.

Strength-toughness relations in sintered and isostatically hot-pressed ZrO2-toughened Al2O3

International Nuclear Information System (INIS)

Hori, S.; Yoshimura, M.; Somiya, S.

1986-01-01

The fracture toughness of fine-grained undoped ZrO 2 -toughened Al 2 O 3 (ZTA) was essentially unchanged by post-sintering hot isostatic pressing and increased monotonically with ZrO 2 additions up to 25 wt%. The strength of ZTA with 5 to 15 wt% tetragonal ZrO 2 , which depended monotonically on the amount of ZrO 2 present before hot isostatic pressing, was increased by pressing but became almost constant between 5 and 15 wt% ZrO 2 addition. The strength appeared to be controlled by pores before pressing and by surface flaws after pressing; the size of flaws after pressing increased with ZrO 2 content. The strength of ZTA containing mostly monoclinic ZrO 2 (20 to 25 wt%) remained almost constant despite the noticeable density increase upon hot isostatic pressing because the strength was controlled by preexisting microcracks whose extent did not change on postsintering pressing. These strength-toughness relations in sintered and isostatically hot-pressed ZTA are explained on the basis of R-curve behavior. The importance of the contribution of microcracks to the toughness of ZTA is emphasized

Volatile organic compound emissions during hot-pressing of southern pine particleboard : panel size effects and trade-off between press time and temperature

Science.gov (United States)

Wenlong Wang; Douglas J. Gardner; Melissa G.D. Baumann

2002-01-01

In previous research, it was shown that decreasing either press temperature or press time generally resulted in decreased volatile organic compound (VOC) emissions during the hot-pressing of southern pine particleboard. However, because it is impossible to reduce both pressing time and temperature while maintaining panel physical and mechanical properties, this study...

Process considerations for hot pressing ceramic nuclear waste forms

International Nuclear Information System (INIS)

Wilson, C.N.; Brite, D.W.

1981-01-01

Spray calcined simulated ceramic nuclear waste powders were hot pressed in graphite, nickel-lined graphite and ZrO 2 -lined Al 2 O 3 dies. Densification, initial off-gas, waste element retention and pellet-die interactions were evaluated. Indicated process considerations and limitations are discussed. 15 figures

Hot isostatic-pressing diagrams for fine-particle beryllium powders

International Nuclear Information System (INIS)

Stoev, P.I.; Papirov, I.I.; Tikhinskij, G.F.; Vasil'ev, A.A.

1995-01-01

Charts of hot isostatic pressing (HIP) for 4 and 8 μm grain beryllium powders are plotted. Values of thickening rates are calculated and their dependences on HIP pressure and temperature are plotted. It is shown, that the relative density powder at growth of HIP pressure and temperature

Room temperature nanoindentation creep of hot-pressed B{sub 6}O

Energy Technology Data Exchange (ETDEWEB)

Machaka, Ronald, E-mail: RMachaka@csir.co.za [Light Metals, Materials Science and Manufacturing, Council for Scientific and Industrial Research, Office F7, Building 14F, P.O. Box 395, Pretoria 0001 (South Africa); DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050 (South Africa); Derry, Trevor E. [DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050 (South Africa); School of Physics, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050 (South Africa); Sigalas, Iakovos [DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050 (South Africa); School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050 (South Africa)

2014-06-01

Nanoindentation has become a widely used and versatile means of characterising the near-surface nanomechanical properties of a wide variety of materials. Yet, the nanomechanical properties of the polycrystalline boron suboxide (B{sub 6}O) material prepared by uniaxial hot-pressing are sparsely known. We recently reported on the nanoindentation profiles, nanoindentation hardness, and elastic modulus determined by using the Oliver–Pharr method. To complement our earlier reports on the analysis of the load–displacement indentation response of hot-pressed B{sub 6}O and for the first time, we present and discuss results giving an insight into the temporal evolution of the nanoindentation creep behaviour in B{sub 6}O ceramics.

Preparation of Ti-aluminide reinforced in situ aluminium matrix composites by reactive hot pressing

International Nuclear Information System (INIS)

Roy, D.; Ghosh, S.; Basumallick, A.; Basu, B.

2007-01-01

Aluminium based metal matrix composites reinforced with in situ Ti-aluminide and alumina particles were prepared by reactive hot pressing a powder mix of aluminium and nanosized TiO 2 powders. The reinforcements were formed in situ by exothermal reaction between the TiO 2 nano crystalline powder and aluminium. The thermal characteristics of the in situ reaction were studied with the aid of Differential scanning calorimetry (DSC). X-ray diffraction (XRD), Energy dispersive spectroscopy (EDS) and Scanning electron microscopy (SEM) techniques were employed to study the microstructural architecture of the composites as a function of hot pressing temperature and volume percent reinforcement. Microhardness measurements on the as prepared in situ aluminium matrix composites exhibit significant increase in hardness with increase in hot pressing temperature and volume fraction of reinforcement

Defect structures in MgB2 wires introduced by hot isostatic pressing

International Nuclear Information System (INIS)

Liao, X Z; Serquis, A; Zhu, Y T; Civale, L; Hammon, D L; Peterson, D E; Mueller, F M; Nesterenko, V F; Gu, Y

2003-01-01

The microstructures of MgB 2 wires prepared by the powder-in-tube technique and subsequent hot isostatic pressing were investigated using transmission electron microscopy. A large amount of crystalline defects including small-angle twisting, tilting and bending boundaries, in which high densities of dislocations reside, was found forming sub-grains within MgB 2 grains. It is believed that these defects resulted from particle deformation during the hot isostatic pressing process and are effective flux pinning centres that contribute to the high critical current densities of the wires at high temperatures and at high fields

Radiophase development in hot-pressed alkoxide-derived titanate ceramics for nuclear waste stabilization

International Nuclear Information System (INIS)

Dickson, F.J.; Mitamura, H.; White, T.J.

1989-01-01

This paper reports phase development as a function of hot-pressing temperature studied in alkoxide-derived titanate-based ceramics doped with a 10 wt% loading of a sodium-rich (NAR) and a sodium-poor (NAP) simulated high-level waste. Pyrochlore was found to be the most abundant phase in both calcine powders. A pseudobrookite phase existed metastably at hot-pressing temperatures between 890 degrees and 920 degrees C. After hot-pressing at 1100 degrees C, the final phase assemblage for the NAP material consisted of zirconolite, hollandite-type, perovskite, alloy, and reduced rutile (Magneli phases). In addition, NAR samples contained hibonite, freudenbergite, and loveringite. Phase development was driven to completion over a very narrow temperature range (≤50 degrees C), beginning at 870 degrees and 850 degrees C for NAP and NAR, respectively, although full densification was not achieved below 1100 degrees C. Both waste forms exhibited comparable microstructure and aqueous durability

Chemical composition and oxidative stability of jussara (Euterpe edulis M.) oil extracted by cold and hot mechanical pressing

International Nuclear Information System (INIS)

Da Cunha, A.L.A.; Freitas, S.P.; Godoy, R.L.O.; Cabral, L.M.C.; Tonon, R.V.

2017-01-01

The aim of this work was to evaluate the effect of mechanical pressing on jussara oil yield, oxidative stability and carotenoid profile with or without heat application. Firstly, jussara pulp was centrifuged for juice extraction, and the resulting cake was dried until reaching 10% moisture content. Then, oil extraction was performed in an expeller press at 25 ºC (cold pressing) and at 50 ºC (hot pressing). The process performance was evaluated by the oil yield, and the crude jussara oil was characterized for fatty acid composition, acid value, carotenoid profile and oxidative stability. Jussara oil contained 74% unsaturated fatty acids, mainly oleic and linoleic acids (48% and 24%, respectively). The oil yield was almost twice as high for the hot process as compared to the cold one. Additionally, hot pressing resulted in 25% higher total carotenoid content as compared to cold pressing, with β-carotene as the most abundant one. Hot and cold pressing showed no difference in oil oxidative stability and fatty acid composition. [es

High density crystalline boron prepared by hot isostatic pressing in refractory metal containers

Science.gov (United States)

Hoenig, C.L.

1993-08-31

Boron powder is hot isostatically pressed in a refractory metal container to produce a solid boron monolith with a bulk density at least 2.22 g/cc and up to or greater than 2.34 g/cc. The refractory metal container is formed of tantalum, niobium, tungsten, molybdenum or alloys thereof in the form of a canister or alternatively plasma sprayed or chemical vapor deposited onto a powder compact. Hot isostatic pressing at 1,800 C and 30 PSI (206.8 MPa) argon pressure for four hours produces a bulk density of 2.34 g/cc. Complex shapes can be made.

Hot Isostatic Press (HIP) vitrification of radwaste concretes

International Nuclear Information System (INIS)

Siemer, D.D.; Scheetz, B.; Gougar, M.L.D.

1995-01-01

Properly formulated and properly ''canned'' radwaste concretes can be readily hot-isostatically-pressed (HIPed) into materials that exhibit performance equivalent to typical radwaste-type glasses. The HIPing conditions (temperature/pressure) required to turn a concrete waste form into a ''vitrified'' waste form are quite mild and therefore consistent with both safety and high productivity. This paper describes the process and its products with reference to its potential application to Idaho Chemical Processing Plant (ICPP) reprocessing wastes

Thermoelectric Properties of Hot-Pressed and PECS-Sintered Magnesium-Doped Copper Aluminum Oxide

Science.gov (United States)

Liu, Chang; Morelli, Donald T.

2011-05-01

Copper aluminum oxide (CuAlO2) is considered as a potential candidate for thermoelectric applications. Partially magnesium-doped CuAlO2 bulk pellets were fabricated using solid-state reactions, hot-pressing, and pulsed electric current sintering (PECS) techniques. X-ray diffraction and scanning electron microscopy were adopted for structural analysis. High-temperature transport property measurements were performed on hot-pressed samples. Electrical conductivity increased with Mg doping before secondary phases became significant, while the Seebeck coefficient displayed the opposite trend. Thermal conductivity was consistently reduced as the Mg concentration increased. Effects of Mg doping, preparation conditions, and future modification on this material's properties are discussed.

Consolidation of W–Ta composites: Hot isostatic pressing and spark and pulse plasma sintering

Energy Technology Data Exchange (ETDEWEB)

Dias, M., E-mail: marta.dias@itn.pt [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Guerreiro, F. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Correia, J.B. [LNEG, Laboratório Nacional de Energia e Geologia, Estrada do Paço do Lumiar, 1649-038 Lisboa (Portugal); Galatanu, A. [National Institute of Materials Physics, Atomistilor 105 bis Bucharest-Magurele, 077125 Ilfov (Romania); Rosiński, M. [Warsaw University of Technology, Faculty of Materials Science and Engineering, Warsaw (Poland); Monge, M.A.; Munoz, A. [Departamento de Física, Univerdidad Carlos III de Madrid, Avd. de la Universidad 30, 28911 Madrid (Spain); Alves, E. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Carvalho, P.A. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

2015-10-15

Highlights: • Consolidation of W–Ta composites using three techniques: HIP, SPS and PPS. • Comparison of consolidation methods in terms of W–Ta interdiffusion and densification. • Microstructure analysis in terms of oxides formation. - Abstract: Composites consisting of tantalum fiber/powder dispersed in a nanostructured W matrix have been consolidated by spark and pulse plasma sintering as well as by hot isostatic pressing. The microstructural observations revealed that the tungsten–tantalum fiber composites consolidated by hot isostatic pressing and pulse plasma sintering presented a continuous layer of Ta{sub 2}O{sub 5} phase at the W/Ta interfaces, while the samples consolidated by spark plasma sintering evidenced a Ta + Ta{sub 2}O{sub 5} eutectic mixture due to the higher temperature of this consolidation process. Similar results have been obtained for the tungsten–tantalum powder composites. A (W, Ta) solid solution was detected around the prior nanostructured W particles in tungsten–tantalum powder composites consolidated by spark and pulse plasma sintering. Higher densifications were obtained for composites consolidated by hot isostatic pressing and pulse plasma sintering.

Coercivity enhancement of HDDR-processed Nd-Fe-B permanent magnet with the rapid hot-press consolidation process

Energy Technology Data Exchange (ETDEWEB)

Nozawa, N. [Magnetic Materials Research Laboratory, NEOMAX Company, Hitachi Metals Ltd., Osaka 618-0013 (Japan); Sepehri-Amin, H. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571 (Japan); Magnetic Materials Center, National Institute for Materials Science, Tsukuba 305-0047 (Japan); Ohkubo, T. [Magnetic Materials Center, National Institute for Materials Science, Tsukuba 305-0047 (Japan); Hono, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571 (Japan); Magnetic Materials Center, National Institute for Materials Science, Tsukuba 305-0047 (Japan); Nishiuchi, T. [Magnetic Materials Research Laboratory, NEOMAX Company, Hitachi Metals Ltd., Osaka 618-0013 (Japan); Hirosawa, S., E-mail: Satoshi_Hirosawa@hitachi-metals.co.j [Magnetic Materials Research Laboratory, NEOMAX Company, Hitachi Metals Ltd., Osaka 618-0013 (Japan)

2011-01-15

High coercivity, fully dense anisotropic permanent magnets of submicron grain sizes were produced by rapid hot-press consolidation of hydrogenation-disproportionation-desorption-recombination (HDDR) processed Nd-Fe-Co-B powders. In the hot-press process, the coercivity of the consolidated material showed a sharp minimum prior to full densification. Thereafter, it reached a value 25% higher than that of the initial powder. Scanning electron microscopy and transmission electron microscopy observations revealed that the variation in H{sub cJ} was caused by a redistribution of Nd along the grain boundaries during hot pressing and that the high coercivity was attributable to the formation of thin, continuous Nd-rich phase along the grain boundaries.

Densification and Grain Growth in Polycrystalline Olivine Rocks Synthesized By Evacuated Hot-Pressing

Science.gov (United States)

Meyers, C. D.; Kohlstedt, D. L.; Zimmerman, M. E.

2017-12-01

Experiments on laboratory-synthesized olivine-rich rocks form the starting material for many investigations of physical processes in the Earth's upper mantle (e.g., creep behavior, ionic diffusion, and grain growth). Typically, a fit of a constitutive law to experimental data provides a description of the kinetics of a process needed to extrapolate across several orders of magnitude from laboratory to geological timescales. Although grain-size is a critical parameter in determining physical properties such as viscosity, broad disagreement persists amongst the results of various studies of grain growth kinetics in olivine-rich rocks. Small amounts of impurities or porosity dramatically affect the kinetics of grain growth. In this study, we developed an improved method for densifying olivine-rich rocks fabricated from powdered, gem-quality single crystals that involves evacuating the pore space, with the aim of refining measurements of the kinetics of mantle materials. In previous studies, olivine powders were sealed in a metal can and hydrostatically annealed at roughly 300 MPa and 1250 °C. These samples, which appear opaque and milky-green, typically retain a small amount of porosity. Consequently, when annealed at 1 atm, extensive pore growth occurs, inhibiting grain growth. In addition, Fourier-transform infrared and confocal Raman spectroscopy reveal absorption peaks characteristic of CO2 in the pores of conventionally hot-pressed material. To avoid trapping of adsorbed contaminants, we developed an evacuated hot-pressing method, wherein the pore space of powder compacts is vented to vacuum during heating and pressurization. This method produces a highly dense, green-tinted, transparent material. No CO2 absorptions peaks exist in evacuated hot-pressed material. When reheated to annealing temperatures at 1 atm, the evacuated hot-pressed material undergoes limited pore growth and dramatically enhanced grain-growth rates. High-strain deformation experiments on

Effect of Furnish on Temperature and Vapor Pressure Behavior in the Center of Mat Panels during Hot Pressing

Directory of Open Access Journals (Sweden)

Muhammad Navis Rofii

2014-07-01

Full Text Available Particleboard achieves its overall performance characteristics during hot pressing process. As this process is influenced by several factors, particularly temperature and pressure, it is very important to understand the behavior of both. This study investigates the effects of furnish materials on temperature and vapor pressure behavior inside particleboard mat panels during hot pressing. Strand type particles from hinoki and ring-flaker recycled wood particles were used as furnish for laboratory-scale particleboard panels with a target density of 0.76 g/cm³. Mat panels with a moisture content of about 10% were hot pressed at a platen temperature of 180°C and an initial pressure of 3 MPa until the mat center reached the same temperature as the platen. A press monitoring device (PressMAN Lite was used for detecting the temperature and vapor pressure change in the center of the mat panels. The study showed that the furnish type affected the temperature and vapor behavior inside the mat panels. Particleboard made of hinoki strand resulted in a longer plateau time, a higher plateau temperature and a higher gas pressure generated during hot pressing than those of ring-flaker recycled wood particles. Mixed board resulted in values between those of the two other furnish materials.

Effect of Hot-Pressing Temperature on the Subsequent Enzymatic Saccharification and Fermentation Performance of SPORL Pretreated Forest Biomass

Science.gov (United States)

Jingzhi Zhang; Andrea Laguna; Craig Clemons; Michael P. Wolcott; Rolland Gleisner; J.Y. Zhu; Xu Zhang

2015-01-01

Methods to increase the energy density ofbiofuel feedstock for shipment are important towards improving supply chain efficiency in upstream processes. Towards this end, densified pretreated lignocellulosic biomass was produced using hot-pressing. The effects offiber hornification induced by hot-pressing on enzymatic digestibilities of lodgepolepine and poplar NE222...

Efficient transfer of large-area graphene films onto rigid substrates by hot pressing.

Science.gov (United States)

Kang, Junmo; Hwang, Soonhwi; Kim, Jae Hwan; Kim, Min Hyeok; Ryu, Jaechul; Seo, Sang Jae; Hong, Byung Hee; Kim, Moon Ki; Choi, Jae-Boong

2012-06-26

Graphene films grown on metal substrates by chemical vapor deposition (CVD) method have to be safely transferred onto desired substrates for further applications. Recently, a roll-to-roll (R2R) method has been developed for large-area transfer, which is particularly efficient for flexible target substrates. However, in the case of rigid substrates such as glass or wafers, the roll-based method is found to induce considerable mechanical damages on graphene films during the transfer process, resulting in the degradation of electrical property. Here we introduce an improved dry transfer technique based on a hot-pressing method that can minimize damage on graphene by neutralizing mechanical stress. Thus, we enhanced the transfer efficiency of the large-area graphene films on a substrate with arbitrary thickness and rigidity, evidenced by scanning electron microscope (SEM) and atomic force microscope (AFM) images, Raman spectra, and various electrical characterizations. We also performed a theoretical multiscale simulation from continuum to atomic level to compare the mechanical stresses caused by the R2R and the hot-pressing methods, which also supports our conclusion. Consequently, we believe that the proposed hot-pressing method will be immediately useful for display and solar cell applications that currently require rigid and large substrates.

Wettability of hot-pressed samples of boron-containing aluminium compounds by liquid metals and alloys

International Nuclear Information System (INIS)

Kharlamov, A.I.; Nizhenko, V.I.; Kirillova, N.V.; Floka, L.I.

2000-01-01

Highly dispersed powders of aluminium borides and borocarbides were sintered by hot pressing method. Temperature dependence of wettability of hot-pressed boride samples (α-AlB 12 and AlB 18 ) and aluminium borocarbides (Al 3 B 48 C 2 , Al 8 B 4 C 2 and AlB 24 C) by liquid aluminium, copper, germanium, silicon and melts Al + 25 wt.%Si and Cu + (3-6) wt.%Ti was studied. Dependence of a compound wettability on the ratio of components in it was analyzed [ru

Reduction of adhesive stain defect in flexible printed circuit board on hot pressing process: a case study of electronic component factory

Directory of Open Access Journals (Sweden)

Sakulkaew Srisang

2014-09-01

Full Text Available The objective of this research is a reduction of an adhesive stain defect in flexible printed circuit board in hot pressing process, the electronic factory. The manufacturing have been processing by sheet type of products with ninety-six pieces of flexible printed circuit boards. Causes of the problem include the before and internal hot pressing process. In process beginning times, the most right row of products between the cooling plate and the hot pressing machine has temperature 71.2◦C that is higher than glass transition temperature (Tg 60◦C. Those products’ temperature lead to evaporate a polyimide adhesive before hot pressing process beginning. The internal hot pressing process include the preheat times and the pressure time. In the preheat time the problem is a gap between lower and upper plate, was under specification(Under 1 mm and leaded to adhesive polyimide stain. In the actuality this time requires temperature and low pressure that mean a gap within 1 – 2 mm (between lower and upper plate. In pressure times the hot pressing plate surface is not flat and products are pressed by insufficient force that it lead to generate an adhesive stain on flexible printed circuit boards. That force is measured by the pre-scale paper and a result, RGB color, is provided. And then color density (From standard color sample and RGB color (From pre-scale paper is found out the relation by Photoshop program and multiple regression theory using. The formula is applied to compare with defect so as to find out the suitable color density (Defects reducing. The solving solutions is provided including the gap reduced adjustment between cooling plate and hot pressing machine before hot pressing process, the plate adjustment within specification in the preheat time and the pressing plate polishing in the pressure time. Results of study and solving are provide defect reduction from 24.4 percentage to 7.2 percentage of total study product.

Reduction of adhesive stain defect in flexible printed circuit board on hot pressing process: A case study of electronic component factory

Directory of Open Access Journals (Sweden)

Sakulkaew Srisang

2015-03-01

Full Text Available The objective of this research is a reduction of an adhesive stain defect in flexible printed circuit board in hot pressing process, the electronic factory. The manufacturing have been processing by sheet type of products with ninety-six pieces of flexible printed circuit boards. Causes of the problem include the before and internal hot pressing process. In process beginning times, the most right row of products between the cooling plate and the hot pressing machine has temperature 71.2◦C that is higher than glass transition temperature (Tg 60◦C. Those products’ temperature lead to evaporate a polyimide adhesive before hot pressing process beginning. The internal hot pressing process include the preheat times and the pressure time. In the preheat time the problem is a gap between lower and upper plate, was under specification (Under 1 mm and leaded to adhesive polyimide stain. In the actuality this time requires temperature and low pressure that mean a gap within 1 – 2 mm (between lower and upper plate. In pressure times the hot pressing plate surface is not flat and products are pressed by insufficient force that it lead to generate an adhesive stain on flexible printed circuit boards. That force is measured by the pre-scale paper and a result, RGB color, is provided. And then color density (From standard color sample and RGB color (From pre-scale paper is found out the relation by Photoshop program and multiple regression theory using. The formula is applied to compare with defect so as to find out the suitable color density (Defects reducing. The solving solutions is provided including the gap reduced adjustment between cooling plate and hot pressing machine before hot pressing process, the plate adjustment within specification in the preheat time and the pressing plate polishing in the pressure time. Results of study and solving are provide defect reduction from 24.4 percentage to 7.2 percentage of total study product.

Hot-pressed geopolymer

DEFF Research Database (Denmark)

Ranjbar, Navid; Mehrali, Mohammad; Maheri, Mahmoud R.

2017-01-01

This research explores the use of simultaneous heating and pressing techniques in order to enhance the mechanical properties of fly ash (FA) based geopolymer under relatively low temperature conditions to ensure minimum-porosity. Four effective parameters of pressing force, alkali activator...

Fabrication of fully ceramic microencapsulated fuel by hot pressing

International Nuclear Information System (INIS)

Lee, H. G.; Kim, D. J; Park, J. Y.; Kim, W. J.; Lee, S. J

2014-01-01

Fully ceramic microencapsulated(FCM) nuclear fuel is one of the recently suggested concept to enhance stability nuclear fuel itself. The requirements to increase the accident tolerance of nuclear fuel are mainly two parts: First, the performance has to be maintained compared to the existing UO 2 nuclear fuel and zircaloy cladding system under the normal operation condition. Second, under the severe accident condition, the high temperature structural integrity has to be kept and the generation rate of hydrogen has to be decrease largely. FCM nuclear fuel consists of tristructural isotropic(TRISO) fuel particle and SiC matrix. The relative thermal conductivity of the SiC matrix as compared to UO 2 is quite good, yielding as-irradiated fuel centerline temperature compared to high temperature for the existing fuel leading to reduced stored energy in the core and reduced operational release of fission products from the fuel. Generally SiC ceramics are fabricated via liquid phase sintering due to strong covalent bonding property and low self-diffusivity coefficient. Hot pressing is very effective method to conduct sintering of SiC powder including different second phase. In this study, SiC-matrix composite including TRISO particles were sintered by hot pressing with Al 2 O 3 -Y 2 O 3 additive system. Various sintering condition were investigated to obtain high relative density above 95%. The internal distribution of TRISO particles within SiC-matrix composite was observed by x-ray radiograph. From the analysis of the cross-section of SiC-matrix composite, the fracture of TRISO particles was investigated. In order to uniform distribution of TRISO particle embedded in the SiC matrix, SiC powder overcoating is considered. SiC matrix composite including TRISO was fabricated by hot pressing. FCM pallets with full density were obtained with Al 2 O 3 -Y 2 O 3 additive system. From the microstructure image, the effect of the sintering additive contents and sintering mechanism

Mechanical and thermal expansion properties of β-eucryptite prepared by sol-gel methods and hot pressing

International Nuclear Information System (INIS)

Xia, L.; Wen, G.W.; Qin, C.L.; Wang, X.Y.; Song, L.

2011-01-01

Research highlights: → Dense LAS glass-ceramics were fabricated by sol-gel and hot pressing technique. → The LAS glass-ceramics have relative good mechanical properties. → The negative thermal expansion behavior of LAS glass-ceramics was investigated. -- Abstract: The microstructures, mechanical properties and thermal expansion behavior of monolithic lithium aluminosilicate glass-ceramics, prepared by sol-gel method and hot pressing, were investigated by using X-ray diffraction, scanning and transmission electron microscopies, three-point bend tests and dilatometry. β-eucryptite appeared as main phase in the monolithic lithium aluminosilicate glass-ceramics. The glass ceramics exhibited high relative densities and the average flexural strength and fracture toughness values were 154 MPa and 2.46 MPa m 1/2 , respectively. The lithium aluminosilicate glass-ceramics hot pressed 1300 and 1350 o C demonstrated negative coefficient of thermal expansion, which was affected by amount and type of crystalline phases.

Mechanical and thermophysical properties of hot-pressed SYNROC B

International Nuclear Information System (INIS)

Hoenig, C.L.; Newkirk, H.W.; Otto, R.A.; Brady, R.L.; Brown, A.E.; Ulrich, A.R.; Lum, R.C.

1981-01-01

The optimal SYNROC compositons for use with commercial waste are reviewed. Large amounts of powder (about 2.5 kg) were prepared by convention al ceramic operations to test the SYNROC concept on a processing scale. Samples, 15.2 cm in diameter, were hot pressed in graphite, and representative samples were cut for microstructural evaluations. Measured mechanical and thermophysical properties did not vary significantly as a function of sample location and were typical of titanate ceramic materials

Ceramic nuclear waste forms. II. A ceramic-waste composite prepared by hot pressing. Progress report and preprint

International Nuclear Information System (INIS)

McCarthy, G.J.

1975-01-01

A feasibility study was conducted to determine whether nuclear waste calcine and a crystalline ceramic matrix can be fabricated by hot pressing into a composite waste form with suitable leaching resistance and thermal stability. It was found that a hard, dense composite could be formed using the typical commercial waste formulation PW-4b and a matrix of α-quartz with a small amount of a lead borosilicate glass added as a consolidation aide. Its density, waste loading, and leaching resistance are comparable to the glasses currently being considered for fixation of nuclear wastes. The hot pressed composite offers a closer approach to thermodynamic stability and improved thermal stability (in monolithic form) compared to glass waste forms. Recommendations for further optimization of the hot pressed waste form are given. (U.S.)

Flux pinning in hot isostatically pressed Bi2Sr2CaCu2Ox

International Nuclear Information System (INIS)

Miller, D.J.; Sengupta, S.; Hettinger, J.D.; Shi, D.; Gray, K.E.; Nash, A.S.; Goretta, K.C.

1992-01-01

Magnetic hysteresis data were taken from 4.2 to 35 K on Bi 2 Sr 2 CaCu 2 O x samples that were hot isostatically pressed at 105 MPa in an inert atmosphere at 825 degree C. One set of samples was pressed for only 15 min while the other was pressed for 120 min. The samples pressed for 15 min contained a high density of dislocations and planar faults, while the samples pressed for 120 min contained fewer dislocations and faults, with most dislocations present within subgrain boundaries. The samples with the complex dislocation/planar fault structures exhibited substantially larger hysteresis loops, suggesting enhanced flux pinning

Process controls for Bi2Te3-Sb2Te3 prepared by mechanical alloying and hot pressing

International Nuclear Information System (INIS)

Lee, Go-Eun; Kim, Il-Ho; Choi, Soon-Mok; Lim, Young-Soo; Seo, Won-Seon; Park, Jae-Soung; Yang, Seung-Ho

2014-01-01

p-Type Bi 2 Te 3 -Sb 2 Te 3 solid solutions were prepared by mechanical alloying (MA) and hot pressing (HP) under different process conditions, after which the transport and the thermoelectric properties were evaluated. The relative densities of all hot-pressed specimens were over 98%, and the microstructure and crystal orientation were independent of the HP direction. All specimens exhibited p-type conduction, and the electrical resistivity was observed to increase slightly with increasing temperature, indicating a degenerate semiconductor behavior. The carrier concentration decreased with increasing HP temperature while the mobility increased. The maximum figure of merit obtained was 0.86 at 323 K for Bi 0.5 Sb 1.5 Te 3 hot-pressed at 648 K.

Effect of phosphorus additions on hot pressing temperature and some properties of WC-Co hard alloys

International Nuclear Information System (INIS)

Dotsenko, V.M.; Simkina, Eh.S.; Tsypin, N.V.

1977-01-01

Results of studies on the effect of phosphorus additions on hot pressing temperature and some properties of VK6 and VK15 hard alloys are given. It is shown that alloying of hard alloys with 3-6 wt % phosphorus gives opportunity to lower substantially (for 200-300 deg) their hot pressing temperature. Hardness and density of alloys with phosphorus do not practically change. Some decrease of strength and wear-resistance characteristics is observed which is obviously connected with irregular distribution of phosphorus in the alloy

Hot pressing effect on (Bi 0.25 Sb 0.75 ) 2 Te 3 mechanical and ...

Indian Academy of Sciences (India)

Hot pressing effect on (Bi0.25Sb0.75)2Te3 mechanical and thermoelectric properties ... The crystal of this compound was prepared, pulverized in a particle size ratio of 64% ... microscopy and, for only once successful attempt, atomic force microscopy. The acquired images ensured to show homogeneous structures for hot ...

Improving the Quality of Hot Stamping Parts with Innovative Press Technology and Inline Process Control

Science.gov (United States)

Vollmer, R.; Palm, C.

2017-09-01

The increasing number of hot stamped parts in the automotive industry is challenging different process areas. This paper presents a method how to improve the production rates over the whole life cycle of a hot forming part. In the core element of a hot forming line, the hydraulic press, mainly two processing steps are performed. Forming and quenching of the sheet metal part. In addition to the forming operation, it is inevitable to optimize the quenching condition in the bottom dead centre in order to reach a fully martensitic structure and tight geometrical tolerances of the part. Deviations in the blank thickness, tool wear, polishing of classical tools impair the quenching condition and therefore the part quality over the time. A new press and tool design has been developed to counter this effect by providing homogenous contact pressure over the whole die. Especially with a multi cavity tool, the new method is advantageous. Test series have shown that the new tool and press concept can produce parts with a blank thickness of 1.0 mm within 8.0 s cycle time. The so called PCH flex principle makes it possible to produce such high output rates under reliable conditions.

Fractographical characterization of hot pressed and pressureless sintered AlN-doped ZrB{sub 2}–SiC composites

Energy Technology Data Exchange (ETDEWEB)

Ahmadi, Zohre [Department of Materials Engineering, Faculty of Mechanical Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of); Nayebi, Behzad [School of Materials and Metallurgy Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Young Researchers and Elite Club, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of); Shahedi Asl, Mehdi [Department of Mechanical Engineering, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of); Ghassemi Kakroudi, Mahdi, E-mail: mg_kakroudi@tabrizu.ac.ir [Department of Materials Engineering, Faculty of Mechanical Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of)

2015-12-15

In this paper, ZrB{sub 2}–SiC composites doped with 0–5 wt.% AlN were prepared by a low pressure hot pressing as well as a pressureless sintering methods at 1900 °C for 2 h. The influence of aluminum nitride addition on the sinterability and microstructure development of such ceramic composites was studied by a fractographical approach. The results revealed that only 1 wt.% AlN can aid the densification process of the hot pressed ceramic composite via the liquid phase sintering mechanism due to the formation of nano-scale metakaolinite spinel layers. In the pressureless sintering method, adding more AlN can increase the formation of gaseous products which raised the amount of porosities in the final microstructure. The formation of nano-graphite phase in the hot pressing process, the formation of Al{sub 2}OC in the pressureless sintering process, and the formation of BN in the both processes were disclosed by X-ray diffraction, SEM and TEM analyses. - Highlights: • The effect of AlN addition on densification of ZrB{sub 2}–SiC composites was studied. • AlN promotes the densification in hot pressed samples by liquid phase formation. • A fully dense composite was obtained by adding 1 wt.% AlN in hot pressing process. • In pressureless sintering, more AlN content intensifies the formation of porosities.

Chemical vapor deposition of tantalum on graphite cloth for making hot pressed fiber reinforced carbide-graphite composite

International Nuclear Information System (INIS)

Hollabaugh, C.M.; Davidson, K.V.; Radosevich, C.L.; Riley, R.E.; Wallace, T.C.

1977-01-01

Conditions for the CVD of a uniform coating of Ta on fibers of a woven graphite cloth were established. The effect of gas composition, pressure, and temperature were investigated, and the conditions that gave the desired results are presented. Several layers of the coated cloth were hot pressed to produce a TaC--C composite having uniformly dispersed, fine-grained TaC in graphite. Three compositions were hot pressed: 15, 25, and 40 volume percent carbide. 8 figures, 2 tables

Hot isostatic pressing of glass-zeolite composites

International Nuclear Information System (INIS)

Hash, M.C.; Pereira, C.; Lewis, M.A.

1996-01-01

Glass-zeolite waste forms are being developed for immobilizing the chloride waste salt generated from the electrometallurgical treatment of spent fuel. Glass-zeolite composites with high densities were made using hot isostatic pressing (HIP) techniques. Processing parameters were investigated to yield desirable structural ceramic properties such as mechanical, chemical, and thermal stability. Limits for these parameters were determined by differential thermal and thermogravimetric analysis. The resulting ceramic properties such as bulk density, open or apparent porosity, and leach resistance were determined. In addition, phase equilibria and particle-size distribution were observed by optical light and electron microscopy. Pre-HIP processing techniques were also studied to ensure intimate mixing of the glass and zeolite powders. Particle size distributions resulting from dry blending procedure are appropriate for needed flow and packing characteristics

Room temperature nanoindentation creep of hot-pressed B6O

CSIR Research Space (South Africa)

Machaka, R

2014-06-01

Full Text Available of the nanoindentation creep behavior in B6O ceramics. 1 Room temperature nanoindentation creep of hot-pressed B6O Ronald Machakaa,b,* , Trevor E. Derryb,d, Iakovos Sigalasb,c aLight Metals, Materials Science and Manufacturing, Council for Scientific..., University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa dSchool of Physics, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, 2050 South Africa Abstract: Nanoindentation has become a widely...

Fabrication of laminated ZrC-SiC composite by vacuum hot-pressing sintering

Directory of Open Access Journals (Sweden)

Yuanyuan Li

2015-03-01

Full Text Available Laminated ZrC-SiC ceramic was prepared through tape casting and hot pressing. The green tapes of ZrC and SiC were prepared at room temperature. In order to improve the density of composite, the binder of green tapes were removed at 550 °C for 1 h. The laminated structure and the cracks propagation path, which is not a straight line, are observed by optical metalloscope. The compact laminated ZrC-SiC composite sintered by vacuum hot-pressing at 1650 °C for 90 min under pressure of 20 MPa was researched by X-ray diffraction and scanning electron microscopy (SEM equipped with energy dispersive X-ray analysis. The results showed that interlayer bonding is tight, and no disordered phase has formed in the interlayers of ZrC or SiC, and the combination mode is physical mechanism.

Techniques for hot-press-bonding dissimilar metal combinations

International Nuclear Information System (INIS)

Watson, R.D.

1966-05-01

High strength diffusionless bonds can be produced in a variety of dissimilar metal combinations by the hot press bonding technique covered by Canadian Patent application 904,548 June 6, 1964. Some of the combinations that can be joined successfully are Zircaloy-2 and 416 stainless steel, 416 stainless steel and mild steel, 1S aluminum and mild steel, Zircaloy-2 and M257 SAP, and Zircaloy-2 and 1S aluminum. Several other combinations were attempted but suitable joints could not be produced. The methods of producing the joints, the joint strength that can be developed and a discussion of some of the problems associated with making the joints are included in the report. (author)

Hot isostatic pressing of nanosized WC-Co hardmetals

International Nuclear Information System (INIS)

Azcona, I.; Ordonez, A.; Sanchez, J.M.; Castro, F.; Dominguez, L.

2001-01-01

A new technique based on hot isostatic pressing (HIP) has been developed to produce dense nanosized WC-Co hardmetals without the addition of grain growth inhibitors. The glass encapsulation process is the key for the effective application of isostatic pressure at temperatures well below those usually required for reaching the closed porosity state in the WC-Co system. Fully dense WC-Co samples with cobalt contents ranging from 10 to 12 wt. % have been obtained by this technique at temperatures between 1000 o C and 1200 o C with 150 MPa of applied isostatic pressure for 30 minutes. The role of isostatic pressure on the activation of densification mechanisms is discussed. (author)

Effect of roll hot press temperature on crystallite size of PVDF film

Energy Technology Data Exchange (ETDEWEB)

Hartono, Ambran, E-mail: ambranhartono@yahoo.com; Sanjaya, Edi [Departement of Physics Faculty of Science and Technology, Islamic State University Syarif Hidayatullah , Jl. Juanda 95 Ciputat Jakarta (Indonesia); Djamal, Mitra; Satira, Suparno; Bahar, Herman [Theoretical High Energy Physics and Instrumentation Group Research, Faculty Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesa 10 Bandung (Indonesia); Ramli [Departement of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Padang, Jl.Prof. Hamka, Padang 25131 (Indonesia)

2014-03-24

Fabrication PVDF films have been made using Hot Roll Press. Preparation of samples carried out for nine different temperatures. This condition is carried out to see the effect of Roll Hot Press temperature on the size of the crystallite of PVDF films. To obtain the diffraction pattern of sample characterization is performed using X-Ray Diffraction. Furthermore, from the diffraction pattern is obtained, the calculation to determine the crystallite size of the sample by using the Scherrer equation. From the experimental results and the calculation of crystallite sizes obtained for the samples with temperature 130 °C up to 170 °C respectively increased from 7.2 nm up to 20.54 nm. These results show that increasing temperatures will also increase the size of the crystallite of the sample. This happens because with the increasing temperature causes the higher the degree of crystallization of PVDF film sample is formed, so that the crystallite size also increases. This condition indicates that the specific volume or size of the crystals depends on the magnitude of the temperature as it has been studied by Nakagawa.

Consolidation of titanium matrix composites to maximum density by different hot pressing techniques

International Nuclear Information System (INIS)

Montealegre Melendez, I.; Neubauer, E.; Danninger, H.

2010-01-01

In this present work, TiMMCs were manufactured through conventional and inductive hot pressing techniques. The starting materials were two titanium based powders as metal matrices, and two types of reinforcements, carbon nanofibres and nano-micro-boron particles. After several manufacturing runs with varying parameters, especially, optimized hot pressing parameters, the titanium compacts were characterized. Density and hardness measurements, chemical analyses and microstructural studies were conducted. The two objectives of this work were achieved. On one hand the influence, in the properties of TiMMCs, of the starting materials as matrix powder and reinforcements was determined. Higher content of impurities from the starting materials affected the hardness and the microstructure of the composites, independently of the manufacturing process. On another hand, the study of variations of the manufacturing process as temperature of consolidation and soaking time was reported. Higher densification was obtained at higher consolidation temperature; however, reaction between the matrix and the carbonaceous reinforcement was detected.

Microstructure and thermoelectric properties of β-FeSi2 ceramics fabricated by hot-pressing and spark plasma sintering

International Nuclear Information System (INIS)

Qu Xiurong; Lue Shuchen; Hu Jianmin; Meng Qingyu

2011-01-01

Highlights: → With increasing hot-pressing (HP) temperature, the thermoelectric figure of merit of β-FeSi 2 ceramics is improved slightly. → The grain size of the sample sintered by the spark plasma sintering (SPS) process is smaller than that by the HP process. → The SPS sample shows excellent thermoelectric performance attributed to low thermal conductivity. - Abstract: The microstructure and thermoelectric properties of β-FeSi 2 ceramics by hot pressing (HP) and spark plasma sintering (SPS) are investigated. With increasing hot-pressing temperature, the density, electronic conductivity and thermal conductivity of the samples increase significantly, the thermoelectric figure of merit is improved slightly. The microstructure study indicates that the sizes of the β-FeSi 2 and ε-FeSi phases in the sample sintered by the SPS process are smaller than that by the HP process. The SPS sample shows excellent thermoelectric performance due to the low thermal conductivity.

Manufacturing of small scale W monoblock mockups by hot radial pressing

International Nuclear Information System (INIS)

Visca, Eliseo; Testani, C.; Libera, S.; Sacchetti, M.

2003-01-01

In the frame of the European Technology R and D programme for International thermonuclear experimental reactor (ITER) and in the area of high heat flux plasma facing components (HHFC), representative small-scale mock-ups were manufactured and tested to compare different concepts and joining technologies (i.e. active brazing, hot isostatic pressing (HIPping), diffusion bonding, etc.). On the basis of the results obtained by thermal fatigue tests, the monoblock concept resulted to be the most robust one, particularly when the HIPping manufacturing technology is used. Within this programme, ENEA developed an alternative technique for manufacturing plasma-facing components with a monoblock geometry of the ITER machine. The basic idea of this technique, named hot radial pressing (HRP), is to perform a radial diffusion bonding between the cooling tube and the armour tile by pressurising the internal tube only and by keeping the process parameters within the range in which the thermo-mechanical properties of the copper alloys are not yet degraded. The HRP is performed by a standard furnace, in which only a section of the canister is heated. The manufacturing procedure and the results of the screening and fatigue thermal tests performed on the ENEA mock-ups are reported in this paper

Solidification of ion-exchange resins by hydrothermal hot-pressing

International Nuclear Information System (INIS)

Kaneko, M.

1993-01-01

The solidification reaction which easily occurs while continuously keeping the mixture of cation and anion exchange resins compressed under hydrothermal conditions has been demonstrated. Dehydration was considered to occur between sulphonic acid (-SO 3 H) from the cation exchange resin and quaternary ammonium [-CH 2 -N(CH 3 ) 3 OH] from anion-exchange resin-on terminal groups. The cation-and anion-exchange resins were mixed in a 1:1 weight ratio, put in a hot-pressing autoclave and compressed between pistons from the top and bottom at 600 kg cm -2 pressure. The material was continuously compressed during hydrothermal treatment at 200 kg cm -2 by a hydraulic jack and heated to a desired temperature with an induction heater. This system could be used for rapid temperature increasing up to 30 o c min -1 . The pressure and temperature were kept constant for 10 min. The autoclave was cooled to room temperature after the hydrothermal treatment. After the specimen was taken out, the ion-exchange radical reactions were estimated and the product structures were examined. The cation- and anion-exchange resin mixture was solidified. The resultant solidified body at a 300 o C reaction condition for 10 min had a 1.0 g cm -3 density and 700 kg cm -2 compressive strength, and the weight loss did not change in distilled water for 2 weeks. On the other hand, a solidification reaction did not occur at below 250 o C when only the cation or anion was solidified, but they were decomposed. These results suggest that a mixture of cation- and anion-exchange resins causes a solidification reaction under hydrothermal hot-pressing conditions at 300 o C. (author)

Mechanical properties of hot-pressed Al-4.5 wt. % Cu/WC composite

Directory of Open Access Journals (Sweden)

Samaneh Bernoosi

2014-12-01

Full Text Available In this study, the elemental powders of aluminum and copper were initially subjected to mechanical alloying using an attrition ball mill under argon atmosphere to produce an Al-4.5 wt% Cu powder alloy. The WC nanoparticles were then added to the powder alloy and milled in a planetary ball mill to explore the role of the WC nanoparticles on the mechanical properties of the fabricated composite powder. The experimental results revealed that a solid solution of Al-Cu could be formed after MA and a good dispersion of the WC nanoparticles in the aluminum matrix was obtained as characterized using X-ray diffraction and scanning electron microscopy, respectively. The results of hardness and compression tests of the hot pressed composites indicated that the MA followed by the hot-press processes was successful to fabricate an alloy and a metal matrix composite with considerable mechanical properties. However, a decreasing trend in the hardness and strength of the composites with the WC contents of more than 5wt% was observed. The maximum values of 260 HV and 575 MPa were obtained for a composite containing 5 wt% of nano ceramic particles.

Preparation of 50Ni-45Ti-5Zr powders by high-energy ball milling and hot pressing

Energy Technology Data Exchange (ETDEWEB)

Marinzeck de Alcantara Abdala, Julia, E-mail: juabdala@yahoo.com.b [Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi, 2911, 12244-000 Sao Jose dos Campos (Brazil); Bacci Fernandes, Bruno, E-mail: brunobacci@yahoo.com.b [Divisao de Engenharia Mecanica, Instituto Tecnologico de Aeronautica, Praca Marechal-do-Ar Eduardo Gomes, 50, 12228-904 Sao Jose dos Campos (Brazil); Santos, Dalcy Roberto dos, E-mail: dalcy@iae.cta.b [Instituto de Aeronautica e Espaco, Centro Tecnologico Aeroespacial, Praca Marechal-do-Ar Eduardo Gomes, 50, 12228-904 Sao Jose dos Campos (Brazil); Rodrigues Henriques, Vinicius Andre, E-mail: vinicius@iae.cta.b [Instituto de Aeronautica e Espaco, Centro Tecnologico Aeroespacial, Praca Marechal-do-Ar Eduardo Gomes, 50, 12228-904 Sao Jose dos Campos (Brazil); Moura Neto, Carlos de, E-mail: mneto@ita.b [Divisao de Engenharia Mecanica, Instituto Tecnologico de Aeronautica, Praca Marechal-do-Ar Eduardo Gomes, 50, 12228-904 Sao Jose dos Campos (Brazil); Saraiva Ramos, Alfeu, E-mail: alfeu@univap.b [Instituto de Pesquisa e Desenvolvimento, Universidade do Vale do Paraiba, Av. Shishima Hifumi, 2911, 12244-000 Sao Jose dos Campos (Brazil)

2010-04-16

This study reports on the preparation of the 50Ni-45Ti-5Zr (at.%) alloy by high-energy ball milling and hot pressing. The elemental powder mixture was processed in silicon nitride and hardened steel vials, and samples were collected after different milling times. To recover the previous powders in addition wet milling isopropyl alcohol (for 20 min) was adopted. The mechanically alloyed powders were hot-pressed under vacuum at 900 {sup o}C for 1 h using pressure levels close to 200 MPa. The milled powders were characterized by means of scanning electron microscopy, X-ray diffraction, and energy dispersive spectrometry techniques. It was noted that the ductile starting powders were continuously cold-welded during ball milling. This fact was more pronounced during the processing of 50Ni-45Ti-5Zr powders in hardened steel vial. After milling for 5 h, the results suggested that amorphous and nanocrystalline structures were achieved. The complete consolidation was found after hot pressing of mechanically alloyed 50Ni-45Ti-5Zr powders, and a large amount of the B2-NiTi phase was formed mainly after processing in stainless steel balls and vial.

Effect of pressing temperature on the wear resistance of a Co-based Cr-Mo powder alloy produced by hot pressing

Energy Technology Data Exchange (ETDEWEB)

Somunkiran, Ilyas [Firat Univ., Elazig (Turkey). Metallurgical and Materials Engineering Dept.; Balin, Ahmet [Siirt Univ. (Turkey). Dept. of Vocational High School

2016-02-01

In this study, Co-based Cr-Mo powder alloy was produced at different pressing temperatures by using hot pressing technique and abrasive wear behaviors of the produced specimens were examined. Produced specimens were exposed to abrasive wear experiment using block on disc wear test device by applying a load of 50 N with 100-mesh SiC abrasive paper. Each specimen was investigated at 25, 50, 75 and 100 m. At the end of the experiment, abrasive wear results of the specimens were determined by calculating their mass losses. Microstructural properties of the specimens which were produced at different pressing temperatures were investigated by optical and SEM examinations and their wear resistances were examined by abrasive wear experiments. Consequently, it was observed that in Co-based Cr-Mo powder alloy produced by hot pressing technique; as sintering temperature increased, size of neck formations between the powder grains increased, porosity decreased and abrasive wear resistance increased. [German] In diesem Beitrag zugrunde liegenden Studie wurde eine Co-basierte Cr-Mo-Legierung mittels Heisspressens hergestellt und der Abrasivverschleisswiderstand dieser Proben untersucht. Die hergestellten Proben wurden dem Abrasivverschleissversuch durch einen Block-Scheibe-Versuchsaufbau unterzogen, wobei eine Kraft von 50 N mit einem SiC-Papier (100 mesh) verwendet wurde. Jede Probe wurde ueber eine Distanz von 25, 50, 75 und 100 m untersucht. Am Ende der jeweiligen Experimente wurden die Abrasivverschleissergebnisse ermittelt, indem die Massenverluste berechnet wurden. Die mikrostrukturellen Eigenschaften der Proben, die bei verschiedenen Presstemperaturen hergestellt wurden, wurden mittels optischer und Rasterelektronenmikroskopie bestimmt und ihr Verschleisswiderstand anhand der Verschleissversuche ermittelt. Schliesslich wurde beobachtet, dass bei steigender Sintertemperatur der heissgespressten Co-basierten Cr-Mo-Pulverlegierung die Groesse der Einschnuerungen zwischen den

Microstructure, hardness, corrosion resistance and porcelain shear bond strength comparison between cast and hot pressed CoCrMo alloy for metal-ceramic dental restorations.

Science.gov (United States)

Henriques, B; Soares, D; Silva, F S

2012-08-01

The purpose of this study was to compare the microstructure, hardness, corrosion resistance and metal-porcelain bond strength of a CoCrMo dental alloy obtained by two routes, cast and hot pressing. CoCrMo alloy substrates were obtained by casting and hot pressing. Substrates' microstructure was examined by the means of Optical Microscopy (OM) and by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Hardness tests were performed in a microhardness indenter. The electrochemical behavior of substrates was investigated through potentiodynamic tests in a saline solution (8g NaCl/L). Substrates were bonded to dental porcelain and metal-porcelain bond strength was assessed by the means of a shear test performed in a universal test machine (crosshead speed: 0.5 mm/min) until fracture. Fractured surfaces as well as undestroyed interface specimens were examined with Stereomicroscopy and SEM-EDS. Data was analyzed with Shapiro-Wilk test to test the assumption of normality. The t-test (pmicrostructures whereas hot pressed specimens exhibited a typical globular microstructure with a second phase spread through the matrix. The hardness registered for hot pressed substrates was greater than that of cast specimens, 438±24HV/1 and 324±8HV/1, respectively. Hot pressed substrates showed better corrosion properties than cast ones, i.e. higher OCP; higher corrosion potential (E(corr)) and lower current densities (i(corr)). No significant difference was found (p<0.05) in metal-ceramic bond strength between cast (116.5±6.9 MPa) and hot pressed (114.2±11.9 MPa) substrates. The failure type analysis revealed an adhesive failure for all specimens. Hot pressed products arise as an alternative to cast products in dental prosthetics, as they impart enhanced mechanical and electrochemical properties to prostheses without compromising the metal-ceramic bond strength. Copyright © 2012 Elsevier Ltd. All rights reserved.

The effect of hot pressing time on the microstructure and properties of Laves phase NbCr{sub 2} alloys

Energy Technology Data Exchange (ETDEWEB)

Xiao, X. [College of Electromechanical Engineering, Nanjing University of Aeronautical and Astronautics, Nanjing 210016 (China); School of Materials Science and Engineering, Nanchang Institute of Aeronautical Technology, Nanchang 330063 (China); Lu, S.Q. [School of Materials Science and Engineering, Nanchang Institute of Aeronautical Technology, Nanchang 330063 (China)], E-mail: niatlusq@126.com; Hu, P.; Huang, M.G.; Nie, X.W. [School of Materials Science and Engineering, Nanchang Institute of Aeronautical Technology, Nanchang 330063 (China); Fu, M.W. [Department of Mechanical Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

2008-06-25

The microstructure and properties were investigated on the Laves phase NbCr{sub 2} alloys prepared through 20 h mechanical alloying of niobium and chromium powders and subsequent hot pressing at 1250 deg. C for different time. The results indicate that the Laves phase NbCr{sub 2} alloy with homogeneous microstructure and fine grains and high relative density is obtained. With the increase of hot pressing time, the density, grain size and Vickers hardness increase, the fracture toughness, however, decreases gradually. The alloy fabricated by hot pressing at 1250 deg. C for 30 min has the best overall properties. Its average grain size reaches about 248 nm, the relative density is 97.8% and the fracture toughness at room temperature is more than 4.7 MPa m{sup 1/2}. Compared with the Laves phase NbCr{sub 2} alloy prepared by arc-melting, which has the fracture toughness of 1.2 MPa m{sup 1/2}, the fracture toughness in this research is increased significantly.

Ductile Fracture Behaviour of Hot Isostatically Pressed Inconel 690 Superalloy

Science.gov (United States)

Cooper, A. J.; Brayshaw, W. J.; Sherry, A. H.

2018-04-01

Herein we assess the differences in Charpy impact behavior between Hot Isostatically Pressed and forged Inconel 690 alloy over the temperature range of 300 °C to - 196 °C. The impact toughness of forged 690 exhibited a relatively small temperature dependence, with a maximum difference of ca. 40 J measured between 300 °C and - 196 °C, whereas the HIP'd alloy exhibited a difference of approximately double that of the forged alloy over the same temperature range. We have conducted Charpy impact testing, tensile testing, and metallographic analyses on the as-received materials as well as fractography of the failed Charpy specimens in order to understand the mechanisms that cause the observed differences in material fracture properties. The work supports a recent series of studies which assess differences in fundamental fracture behavior between Hot Isostatically Pressed and forged austenitic stainless steel materials of equivalent grades, and the results obtained in this study are compared to those of the previous stainless steel investigations to paint a more general picture of the comparisons between HIP vs forged material fracture behavior. Inconel 690 was selected in this study since previous studies were unable to completely omit the effects of strain-induced martensitic transformation at the tip of the Chary V-notch from the fracture mechanism; Inconel 690 is unable to undergo strain-induced martensitic transformation due to the alloy's high nickel content, thereby providing a sister study with the omission of any martensitic transformation effects on ductile fracture behavior.

Hot pressing of uranium nitride and mixed uranium plutonium nitride

International Nuclear Information System (INIS)

Chang, J.Y.

1975-01-01

The hot pressing characteristics of uranium nitride and mixed uranium plutonium nitride were studied. The utilization of computer programs together with the experimental technique developed in the present study may serve as a useful purpose of prediction and fabrication of advanced reactor fuel and other high temperature ceramic materials for the future. The densification of nitrides follow closely with a plastic flow theory expressed as: d rho/ dt = A/T(t) (1-rho) [1/1-(1-rho)/sup 2/3/ + B1n (1-rho)] The coefficients, A and B, were obtained from experiment and computer curve fitting. (8 figures) (U.S.)

Microstructure of in-situ Synthesized (TiB+TiC)/Ti Composites Prepared by Hot-pressing

Institute of Scientific and Technical Information of China (English)

Zhenzhu ZHENG; Lin GENG; Honglin WANG; Weimin ZHOU; Hongyu XU

2003-01-01

In-situ 5 vol.pct TiB whiskers and TiC particulates reinforced Ti composites were fabricated by blending Ti powderand B4C particulates followed by reactive hot-pressing. The microstructure of the composites was investigated byusing differential scanning c

Microstructure characteristics of high borated stainless steel fabricated by hot-pressing sintering

Energy Technology Data Exchange (ETDEWEB)

Zhou, Xuan; Wang, Mingjia, E-mail: mingjiawangysu@126.com; Zhao, Hongchang

2016-04-25

The present study investigated the microstructure of powder metallurgy (P/M) high borated stainless steel through hot-pressing sintering in a temperature range of 1000–1150 °C within 30 min under 30 MPa. Microstructure and phase examinations were carried out by applying scanning electron microscope, electron backscatter diffraction and X-ray diffraction analysis. The results of as-atomized powders demonstrated that many powders kept egg-type structure with an austenite outer layer and the eutectic borides were much finer than those in traditional cast products. Microstructure studies revealed that borides suffered Ostwald ripening and were significantly influenced by the sintering temperature. Orientation maps indicated that the inter-particle contact areas consisted of equiaxed grains and the regions consisting of large elongated grains partly inherited the microstructure characteristics of as-atomized powder particles. Furthermore, the mechanisms governing the morphological changes in microstructure were discussed. - Highlights: • Near-complete densification could be obtained through hot-pressing sintering. • There was no phase transformation and present phases were M{sub 2}B and austenite. • Borides suffered Ostwald ripening and were significantly influenced by temperature. • Inter-particle contact areas consisted of equiaxed grains for recrystallization. • Deformation-free zones exhibited elongated grains for dendritic arms coarsening.

The microstructures and mechanical properties of Al-15Si-2.5Cu-0.5Mg/(wt%)B{sub 4}C composites produced through hot pressing technique and subjected to hot extrusion

Energy Technology Data Exchange (ETDEWEB)

Ozer, Alpay, E-mail: alpiozer@gmail.com

2016-11-01

In this study, B{sub 4}C (5, 10, and 15 wt%) particle-reinforced Ecka Alumix 231{sup ®} aluminum matrix composites were produced through the hot pressing technique. Some of these samples were subjected to hot extrusion as a secondary treatment at 4:1 ratio at a temperature of 555 °C. The obtained samples were subjected to density measurement, hardness test, microstructure analysis, and three-point bending test, and their fracture surfaces were examined. A density of over 99% was found in the samples. Al-rich solid solution and primary Si, CuAl{sub 2}, Al{sub 2}CuMg, and Mg{sub 2}Si phases in the microstructure were determined through X-ray diffraction analysis. Grain sizes were found to be 20 μm and 2 μm in the microstructures of the samples produced through hot pressing technique and of those subjected to additional hot extrusion, respectively. High hardness values were obtained in the samples subjected to hot extrusion. In these samples, wt% B{sub 4}C particle ratio and transverse rupture strength increased considerably. Furthermore, the highest compressive strain value was obtained in the 10 wt% B{sub 4}C particle-reinforced composites subjected to hot extrusion. - Highlights: • Liquid phase formed at the temperature of hot pressing and hot extrusion. • In the samples, over 99.19% density was obtained. • Average matrix grain size was measured to be 2 μm through hot extrusion. • As wt% B{sub 4}C ratio increased, transverse rupture strength values increased. • High compressive strain values were obtained in the hot extrusion samples.

Hot Deformation Behavior and Pulse Current Auxiliary Isothermal Forging of Hot Pressing Sintering TiAl Based Alloys.

Science.gov (United States)

Shi, Chengcheng; Jiang, Shaosong; Zhang, Kaifeng

2017-12-16

This paper focuses on the fabrication of as-forged Ti46.5Al2Cr1.8Nb-(W, B) alloy via pulse current auxiliary isothermal forging (PCIF). The starting material composed of near gamma (NG) microstructure was fabricated by adopting pre-alloyed powders via hot pressing sintering (HPS) at 1300 °C. Isothermal compression tests were conducted at a strain rate range of 0.001-0.1 s -1 and a temperature range of 1125-1275 °C to establish the constitutive model and processing map. The optimal hot deformation parameters were successfully determined (in a strain rate range of 10 -3 -2.5 × 10 -3 s -1 and temperature range of 1130-1180 °C) based on the hot processing map and microstructure observation. Accordingly, an as-forged TiAl based alloy without cracks was successfully fabricated by PCIF processing at 1175 °C with a nominal strain rate of 10 -3 s -1 . Microstructure observation indicated that complete dynamic recrystallization (DRX) and phase transformation of γ→α₂ occurred during the PCIF process. The elongation of as-forged alloy was 136%, possessing a good secondary hot workability, while the sintered alloy was only 66% when tested at 900 °C with a strain rate of 2 × 10 -4 s -1 .

Mechanical properties and porosity of dental glass-ceramics hot-pressed at different temperatures

Directory of Open Access Journals (Sweden)

Carla Castiglia Gonzaga

2008-09-01

Full Text Available The objective of this work was to evaluate biaxial-flexural-strength (σf, Vickers hardness (HV, fracture toughness (K Ic, Young's modulus (E, Poisson's ratio (ν and porosity (P of two commercial glass-ceramics, Empress (E1 and Empress 2 (E2, as a function of the hot-pressing temperature. Ten disks were hot-pressed at 1065, 1070, 1075 and 1080 °C for E1; and at 910, 915, 920 and 925 °C for E2. The porosity was measured by an image analyzer software and s f was determined using the piston-on-three-balls method. K Ic and HV were determined by an indentation method. Elastic constants were determined by the pulse-echo method. For E1 samples treated at different temperatures, there were no statistical differences among the values of all evaluated properties. For E2 samples treated at different temperatures, there were no statistical differences among the values of σf, E, and ν, however HV and K Ic were significantly higher for 910 and 915 °C, respectively. Regarding P, the mean value obtained for E2 for 925 °C was significantly higher compared to other temperatures.

Process and equipment development for hot isostatic pressing treatability study

Energy Technology Data Exchange (ETDEWEB)

Bateman, Ken; Wahlquist, Dennis; Malewitz, Tim

2015-03-01

Battelle Energy Alliance (BEA), LLC, has developed processes and equipment for a pilot-scale hot isostatic pressing (HIP) treatability study to stabilize and volume reduce radioactive calcine stored at Idaho National Laboratory (INL). In 2009, the U. S. Department of Energy signed a Record of Decision with the state of Idaho selecting HIP technology as the method to treat 5,800 yd^3 (4,400 m^3) of granular zirconia and alumina calcine produced between 1953 and 1992 as a waste byproduct of spent nuclear fuel reprocessing. Since the 1990s, a variety of radioactive and hazardous waste forms have been remotely treated using HIP within INL hot cells. To execute the remote process at INL, waste is loaded into a stainless-steel or aluminum can, which is evacuated, sealed, and placed into a HIP furnace. The HIP simultaneously heats and pressurizes the waste, reducing its volume and increasing its durability. Two 1 gal cans of calcine waste currently stored in a shielded cask were identified as candidate materials for a treatability study involving the HIP process. Equipment and materials for cask-handling and calcine transfer into INL hot cells, as well as remotely operated equipment for waste can opening, particle sizing, material blending, and HIP can loading have been designed and successfully tested. These results demonstrate BEA’s readiness for treatment of INL calcine.

Effect of deformation ratios on grain alignment and magnetic properties of hot pressing/hot deformation Nd-Fe-B magnets

Science.gov (United States)

Guo, Zhaohui; Li, Mengyu; Wang, Junming; Jing, Zheng; Yue, Ming; Zhu, Minggang; Li, Wei

2018-05-01

The magnetic properties, microstructure and orientation degrees of hot pressing magnet and hot deformation Nd-Fe-B magnets with different deformation ratios have been investigated in this paper. The remanence (Br) and maximum magnetic energy product ((BH)max) were enhanced gradually with the deformation ratio increasing from 0% to 70%, whereas the coercivity (HCj) decreased. The scanning electron microscopy (SEM) images of fractured surfaces parallel to the pressure direction during hot deformation show that the grains tend to extend perpendicularly to the c-axes of Nd2Fe14B grains under the pressure, and the aspect ratios of the grains increase with the increase of deformation ratio. Besides, the compression stress induces the long axis of grains to rotate and the angle (θ) between c-axis and pressure direction decreases. The X-ray diffraction (XRD) patterns reveal that orientation degree improves with the increase of deformation ratio, agreeing well with the SEM results. The hot deformation magnet with a deformation ratio of 70% has the best Br and (BH)max, and the magnetic properties are as followed: Br=1.40 T, HCj=10.73 kOe, (BH)max=42.30 MGOe.

Waste treatment process by solidifying cementitious materials using hydrothermal hot-pressing

International Nuclear Information System (INIS)

Matsumoto, Y.; Kamakura, T.; Yamasaki, N.; Hashida, T.

2001-01-01

Solidification of low-level radioactive wastes containing Na 2 SO 4 with cement by hydrothermal hot-pressing (HHP) technique was examined. Relatively high mechanical strength, reduced leaching ratio of SO 3 , and higher resistance to the carbonation of the HHP product were attained in comparison with conventional concrete. The solidification by the HHP treatment may be proceeded by the rearrangement of particles and the bonding material formation among the particles by dissolution-deposition process. The possibility of developing the accelerated testing method for duration of cemented materials by hydrothermal method was discussed. (author)

Hot isostatic press waste option study report

International Nuclear Information System (INIS)

Russell, N.E.; Taylor, D.D.

1998-02-01

A Settlement Agreement between the Department of Energy and the State of Idaho mandates that all high-level radioactive waste now stored at the Idaho Chemical Processing Plant be treated so that it is ready to move out of Idaho for disposal by the target date of 2035. This study investigates the immobilization of all Idaho Chemical Processing Plant calcine, including calcined sodium bearing waste, via the process known as hot isostatic press, which produces compact solid waste forms by means of high temperature and pressure (1,050 C and 20,000 psi), as the treatment method for complying with the settlement agreement. The final waste product would be contained in stainless-steel canisters, the same type used at the Savannah River Site for vitrified waste, and stored at the Idaho National Engineering and Environmental Laboratory until a national geological repository becomes available for its disposal. The waste processing period is from 2013 through 2032, and disposal at the High Level Waste repository will probably begin sometime after 2065

Hot isostatic press waste option study report

Energy Technology Data Exchange (ETDEWEB)

Russell, N.E.; Taylor, D.D.

1998-02-01

A Settlement Agreement between the Department of Energy and the State of Idaho mandates that all high-level radioactive waste now stored at the Idaho Chemical Processing Plant be treated so that it is ready to move out of Idaho for disposal by the target date of 2035. This study investigates the immobilization of all Idaho Chemical Processing Plant calcine, including calcined sodium bearing waste, via the process known as hot isostatic press, which produces compact solid waste forms by means of high temperature and pressure (1,050 C and 20,000 psi), as the treatment method for complying with the settlement agreement. The final waste product would be contained in stainless-steel canisters, the same type used at the Savannah River Site for vitrified waste, and stored at the Idaho National Engineering and Environmental Laboratory until a national geological repository becomes available for its disposal. The waste processing period is from 2013 through 2032, and disposal at the High Level Waste repository will probably begin sometime after 2065.

Characterization of hot isostatically pressed Bi-Sr-Ca-Cu-O as a function of consolidation variables

International Nuclear Information System (INIS)

Goretta, K.C.; Miller, D.J.; Poeppel, R.B.; Nash, A.S.

1992-01-01

This paper reports that fully dense, bulk Bi 2 Sr 1.7 CaCu 2 O x superconductor pellets were made by hot isostatic pressing in an inert atmosphere. Electron microscopy revealed that rotation and bending of the platelike 2212 grains were responsible for much of the densification. Under processing conditions of 825 degrees C and 105 MPa, dense pellets were obtained in 15 min. Many dislocations, planar faults, and, perhaps, intergrowths of the Bi 2 Cr 2 CuO x phase were produced during pressing. The dislocations were largely present in subgrain boundaries when the pressing times were increased to 45-120 min

Means to rise stability of matrices for hot pressing of non-ferrous metals

International Nuclear Information System (INIS)

Nagajtsev, A.A.; Piguzova, D.Kh.; Vajnpres, L.V.

1975-01-01

The paper deals with the basic trends adopted both in the USSR and abroad with respect to the development and industrial usage of new materials for hot pressing dies. Methods of their strengthening are also indicated. The paper presents results of production tests of new die steels and refractory alloys at a number of factories processing non-ferrous metals. The problems of their wide application in this field are considered

Numerical simulation of hot-pressed veneer products: Forming - Spring back – Distortion

DEFF Research Database (Denmark)

Ormarsson, Sigurdur; Sandberg, Dick

2007-01-01

Customers demand very high quality of veneered furniture products with regard to surface appearance, shape stability and stiffness. To meet these requirements, it is important to improve the manufacturing process by a better understanding of the thermo-hygro-mechanical behaviour of the individual...... veneers. During the manufacture of strongly curved products, the veneers are exposed to large membrane and bending deformations and to high pressure in the radial fibre direction. When hot-press forming is used, the veneers are also exposed to a high surface temperature during the pressing time (curing...... time). These severe conditions can result in plastic deformation perpendicular to the veneer surface as well as mechano-sorptive strains in the curved regions, since the heating can have a significant influence on the moisture distribution. How strong an influence these factors have on the distortion...

Ductility in hot isostatically pressed 250-grade maraging steel

International Nuclear Information System (INIS)

German, R.M.; Smugeresky, J.E.

1978-01-01

Prealloyed 250-grade maraging steel powder produced by the rotating electrode process was fully consolidated by hot isostatic pressing (HIP) at 1100 and 1200 0 C. The strength following aging (3 h at 480 0 C) equalled that of wrought material; however, ductility was negligible. This lack of ductility in the powder metallurgy product was traced to titanium segregation which occurred at the powder surface during power production. The formation of a titanium intermetallic at the prior particle boundaries during aging caused failure at low plastic strains. Altered aging treatments successfully broke up the embrittling film and resulted in a significant ductility recovery for the HIP material. Analysis of the fracture process indicates that further ductility gains are possible by reducing the titanium content, refining the particle size, and optimizing the thermal cycles

Properties of nonvolatile and antibacterial bioboard produced from bamboo macromolecules by hot pressing

Directory of Open Access Journals (Sweden)

Shengbo Ge

2018-03-01

Full Text Available Employing the antibacterial property of industrial bamboo vinegar (IBV and the photocatalytic degradation of TiO2, bamboo macromolecules were pretreated and processed into nonvolatile and antibacterial bio board (NVABB. The NVABB was then analyzed by conducting Fourier-transform infrared spectroscopy, thermogravimetric analysis and differential thermal analysis. Results show that NVABB samples had average density of 0.96 g/cm3, which is appropriate for application. In terms of physical and mechanical properties, the best NVABB sample obtained from IBV, TiO2 and bamboo had an IBV pretreatment time of 10 min, 2% TiO2 and 1% bamboo charcoal. Fourier-transform infrared spectroscopy demonstrated that optimum conditions for hot pressing were a temperature of 170 °C, duration of 15 min and the addition of IBV and TiO2. Thermogravimetric analysis/differential thermal analysis curves suggest that the thermal degradation of NVABB was less than that of bamboo and that hot pressing obviously increased the thermal stability of HDBB samples. Analysis of the antimicrobial effect revealed that IBV pretreatment improves the antibacterial property of NVABB. Keywords: Industrial bamboo vinegar, Nonvolatile and antibacterial bio board, Bamboo macromolecules, Fourier-transform infrared spectroscopy, Thermogravimetric analysis/differential thermal analysis

Effect of surface acid etching on the biaxial flexural strength of two hot-pressed glass ceramics.

Science.gov (United States)

Hooshmand, Tabassom; Parvizi, Shaghayegh; Keshvad, Alireza

2008-07-01

The purpose of this study was to assess the effect of surface acid etching on the biaxial flexural strength of two hot-pressed glass ceramics reinforced by leucite or lithium disilicate crystals. Forty glass ceramic disks (14-mm diameter, 2-mm thick) consisting of 20 leucite-based ceramic disks (IPS Empress) and 20 lithia disilicate-based ceramic (IPS Empress 2) were produced by hot-pressing technique. All specimens were polished and then cleaned ultrasonically in distilled water. Ten specimens of each ceramic group were then etched with 9% hydrofluoric (HF) acid gel for 2 minutes and cleaned ultrasonically again. The biaxial flexural strength was measured by the piston-on-three-ball test in a universal testing machine. Data based on ten specimens in each group were analyzed by two-way ANOVA (alpha= 0.05). Microstructure of ceramic surfaces before and after acid etching was also examined by a scanning electron microscope. The mean biaxial flexural strength values for each group tested were (in MPa): nonetched IPS Empress = 118.6 +/- 25.5; etched IPS Empress = 102.9 +/- 15.4; nonetched IPS Empress 2 = 283.0 +/- 48.5; and etched IPS Empress 2 = 250.6 +/- 34.6. The results showed that the etching process reduced the biaxial flexural strengths significantly for both ceramic types (p= 0.025). No significant interaction between the ceramic type and etching process was found (p= 0.407). From the results, it was concluded that surface HF acid etching could have a weakening effect on hot-pressed leucite or lithia disilicate-based glass ceramic systems.

Microstructure and mechanical properties of Ti–22Al–25Nb alloy fabricated by vacuum hot pressing sintering

Energy Technology Data Exchange (ETDEWEB)

Jia, Jianbo, E-mail: jiajianbohit@163.com [National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China); School of Mechanical Engineering, Beihua University, Jilin 132021 (China); Zhang, Kaifeng; Jiang, Shaosong [National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China)

2014-10-20

A study has been undertaken to verify the feasibility of using a powder metallurgy (P/M) approach to fabricate Ti–22Al–25Nb alloys. Pre-alloyed powders with a nominal composition of Ti–22Al–25Nb (at%) obtained by argon atomization were sieved to the spherical size less than 180 μm and used for the fabrication of P/M Ti–22Al–25Nb alloys via hot pressing in vacuum. Vacuum hot pressing sintering was carried out in a temperature range of 950–1200 °C with a pressure of 35 MPa for 1 h followed by furnace cooling. Microstructure and phase composition examinations of the as-atomized powders and hot pressed (HP'ed) samples were conducted by applying optical microscopy, back-scatter electron imaging and X-ray diffraction analysis. Tensile tests were studied at room temperature and 650 °C, respectively. The results showed that all HP'ed samples were composed of coarse equiaxed B2 grains, fine lamellar O phase inside the B2 grains, and some α{sub 2} along B2 grain boundaries. The elongations of HP'ed samples were less than 3.95%, indicating the bad ductility at room temperature. However, the elongations were improved as the tensile temperature increased to 650 °C. The sample sintered at 1050 °C exhibited a better ductility with the elongation of 7.97% at 650 °C than that of other samples.

Biodegradable Poly(Lactic Acid/Multiwalled Carbon Nanotube Nanocomposite Fabrication Using Casting And Hot Press Techniques

Directory of Open Access Journals (Sweden)

Park S.G.

2015-06-01

Full Text Available Biodegradable advanced polymer composites have recently received a large amount of attention. The present study aimed to design poly(lactic acid multiwalled carbon nanotube nanocomposites (PLA/MWCNTs using a simple fabrication technique. A PLA sheet was first dissolved in dichloromethane, and MWCNTs were subsequently added at various concentrations (0.5, 1.5 and 5% while applying shear strain stirring to achieve dispersion of carbon nanotubes (CNTs. These solutions were then molded and a hot press was used to generate sheets free of voids with entrapped solvent. The prepared samples were characterized using field emission scanning electron microscopy (FE-SEM, x-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, and thermogravimetric analysis (TGA. Our data showed composite samples free of defects and voids, indicating that the hot press is capable of generating sufficiently compact polymer matrices. Additionally, TGA and FTIR showed significant bonding interactions between the PLA matrix and the nano-fillers. Collectively, our results suggest that incorporation of CNTs as nano-fillers into biodegradable polymers may have multiple applications in many different sectors.

Encapsulation of krypton-85 in zeolite molecular sieve with a hot isostatic press

International Nuclear Information System (INIS)

Christensen, A.B.; DelDebbio, J.A.; Knecht, D.A.; Tanner, J.E.

1986-01-01

This paper describes pilot and full-scale experiments which demonstrated the feasibility of immobilizing Kr-85 in a zeolite 5A/glass mixture and compacting it before disposal. The full volume of a one-liter hot isostatic press (HIP) was used to trap argon in zeolite 5A. For radioactive krypton the HIP was modified to isolate the Kr-85 in the work zone. Details of the HIP modifications, experimental procedure, and sample analysis are reported

Process simulation and experimental validation of Hot Metal Gas Forming with new press hardening steels

Science.gov (United States)

Paul, A.; Reuther, F.; Neumann, S.; Albert, A.; Landgrebe, D.

2017-09-01

One field in the work of the Fraunhofer Institute for Machine Tools and Forming Technology IWU in Chemnitz is industry applied research in Hot Metal Gas Forming, combined with press hardening in one process step. In this paper the results of investigations on new press hardening steels from SSAB AB (Docol®1800 Bor and Docol®2000 Bor) are presented. Hot tensile tests recorded by the project partner (University of West Bohemia, Faculty of Mechanical Engineering) were used to create a material model for thermo-mechanical forming simulations. For this purpose the provided raw data were converted into flow curve approximations of the real stress-real strain-curves for both materials and afterwards integrated in a LS-DYNA simulation model of Hot Metal Gas Forming with all relevant boundary conditions and sub-stages. Preliminary experimental tests were carried out using a tool at room temperature to permit evaluation of the forming behaviour of Docol 1800 Bor and Docol 2000 Bor tubes as well as validation of the simulation model. Using this demonstrator geometry (outer diameter 57 mm, tube length 300 mm, wall thickness 1.5 mm), the intention was to perform a series of tests with different furnace temperatures (from 870 °C to 1035 °C), maximum internal pressures (up to 67 MPa) and pressure build-up rates (up to 40 MPa/s) to evaluate the formability of Docol 1800 Bor and Docol 2000 Bor. Selected demonstrator parts produced in that way were subsequently analysed by wall thickness and hardness measurements. The tests were carried out using the completely modernized Dunkes/AP&T HS3-1500 hydroforming press at the Fraunhofer IWU. In summary, creating a consistent simulation model with all relevant sub-stages was successfully established in LS-DYNA. The computation results show a high correlation with the experimental data regarding the thinning behaviour. The Hot Metal Gas Forming of the demonstrator geometry was successfully established as well. Different hardness values

Brine migration in hot-pressed polycrystalline sodium chloride

International Nuclear Information System (INIS)

Biggers, J.V.; Dayton, G.O.

1982-12-01

This report describes experiments designed to provide data on brine migration in polycrystalline salt. Polycrystalling samples of various grain sizes, density, and purity were prepared from several commercial-grade salts by hot-pressing. Three distinct experimental set-ups were used to place salt billets in an induced thermal gradient in contact with brine source. The test designs varied primarily in the way in which the thermal gradient was applied and monitored and the way in which brine migration was determined. All migration was in enclosed vessels which precluded visual observation of brine movement through the microstructure. Migration velocities were estimated either by the timed appearance of brine at the hot face of the sample, or by determination of the penetration distance of migration artifacts in the microstructure after tests of fixed duration. For various reasons both of these methods were subject to a large degree of error. Our results suggest, however, that the migration velocity in dense polycrystalline salt may be at least an order of magnitude greater than that suggested by single-crystal experiments. Microstructural analysis shows that brine prefers to migrate along paths of high crystalline activity such as grain and subgrain boundaries and is dispersed rather quickly in the microstructure. A series of tests were performed using various types of tracers in brine in order to flag migration paths and locate brine in the microstructure more decisively. These attempts failed and it appears that only the aqueous portion of the brine moves through the microstructure with the dissolved ions being lost and replaced rather quickly. This suggests the use of deuterium as a tracer in future work

Thermoelectric properties of n-type Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} fabricated by mechanical alloying and hot pressing

Energy Technology Data Exchange (ETDEWEB)

Kim, H J; Choi, J S; Oh, T S; Hyun, D B

1997-07-01

Thermoelectric properties of polycrystalline Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} (0.05 {le} x {le} 0.25), fabricated by mechanical alloying and hot pressing, have been investigated. Formation of n-type Bi{sub 2}(Te{sub 0.9}Se{sub 0.1}){sub 3} alloy powders was completed by mechanical alloying for 3 hours at ball-to-material ratio of 5:1, and processing time for Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} formation increased with Bi{sub 2}Se{sub 3} content x. Figure-of-merit of Bi{sub 2}(Te{sub 0.9}Se{sub 0.1}) was markedly increased by hot pressing at temperatures above 450 C, and maximum value of 1.9 x 10{sup {minus}3}/K was obtained by hot pressing at 550 C. With addition of 0.015 wt% Bi as acceptor dopant, figure-of-merit of Bi{sub 2}(Te{sub 0.9}Se{sub 0.1}){sub 3} was hot pressed at 550 C, could be improved to 2.1 x 10{sup {minus}3}/K. When Bi{sub 2}(Te{sub 1{minus}x}Se{sub x}){sub 3} was hot pressed at 550 C, figure-of-merit increased from 1.14 x 10{sup {minus}3}/K to 1.92 x 10{sup {minus}3}/K with increasing Bi{sub 2}Se{sub 3} content x from 0.05 to 0.15, and then decreased to 1.30 x 10{sup {minus}3}/K for x = 0.25 composition.

Investigation of a hot-pressed Nb–Ti–Al alloy: Mechanical alloying, microstructure and mechanical property

Energy Technology Data Exchange (ETDEWEB)

Shi, Zhiwu; Wei, Hua; Zhang, Hongyu; Jin, Tao; Sun, Xiaofeng; Zheng, Qi, E-mail: qzheng@imr.ac.cn

2016-01-10

The Nb–23Ti–15Al (at%) alloy was prepared by mechanical alloying (MA) and hot-pressing (HPing). The microstructure evolution of powder particles during MA and its influence on the microstructure and mechanical properties of the hot-pressed (HPed) alloy have been investigated. The powder and HPed alloy were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that particle size increases in the first stage and then decreases in the second stage during MA; as milling speed increases, mechanically alloyed (MAed) powder with convoluted elemental lamellae, homogeneous Nb solid-solution and an amorphous phase could be obtained respectively in 24 h. Higher homogeneity in microstructure and composition of the MAed powder particles promotes the precipitation of the δ phase and refines the β and Ti(O,C) phases in the HPed alloy. Moreover, due to the phase equilibrium changes caused by Fe and Cr in the amorphous powder, σ phase appears in the alloy as a stable phase instead of the δ phase. Properly MAed powder contributes to higher hardness of the HPed alloy, for reasons of microstructure refinement and sufficient precipitating of strengthening phases.

Investigation of a hot-pressed Nb–Ti–Al alloy: Mechanical alloying, microstructure and mechanical property

International Nuclear Information System (INIS)

Shi, Zhiwu; Wei, Hua; Zhang, Hongyu; Jin, Tao; Sun, Xiaofeng; Zheng, Qi

2016-01-01

The Nb–23Ti–15Al (at%) alloy was prepared by mechanical alloying (MA) and hot-pressing (HPing). The microstructure evolution of powder particles during MA and its influence on the microstructure and mechanical properties of the hot-pressed (HPed) alloy have been investigated. The powder and HPed alloy were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that particle size increases in the first stage and then decreases in the second stage during MA; as milling speed increases, mechanically alloyed (MAed) powder with convoluted elemental lamellae, homogeneous Nb solid-solution and an amorphous phase could be obtained respectively in 24 h. Higher homogeneity in microstructure and composition of the MAed powder particles promotes the precipitation of the δ phase and refines the β and Ti(O,C) phases in the HPed alloy. Moreover, due to the phase equilibrium changes caused by Fe and Cr in the amorphous powder, σ phase appears in the alloy as a stable phase instead of the δ phase. Properly MAed powder contributes to higher hardness of the HPed alloy, for reasons of microstructure refinement and sufficient precipitating of strengthening phases.

Microstructural evolution during hot pressing of the blended elemental Ti-6%Al-7%Nb alloy

International Nuclear Information System (INIS)

Henriques, V.A.R.; Sandim, H.R.Z.; Coelho, G.C.; Silva, C.R.M. da

2003-01-01

The Ti-6%Al-7%Nb (wt.%) α-β alloy was developed aiming the replacement of the traditional Ti-6%Al-4%V alloy in surgical implants owing to its larger biocompatibility. Samples of this alloy were obtained using the blended elemental (BE) technique. The isochronal hot pressing of the compacts was carried out in the range 700-1500 deg. C with a compaction pressure of 20 MPa and a heating rate of 20 deg. C min -1 . In this work, the behavior of the elementary powders during the hot pressing and the corresponding microstructural evolution were investigated. The alloy was characterized by means of scanning electron microscopy (SEM) in the backscattered mode (BSE), X-ray diffraction (XRD), and density measurements. The results indicate that the homogenization of the alloy is diffusion-controlled and Ti.Al intermediary compounds (TiAl and Ti 3 Al) are formed at lower temperatures. With increasing temperature, homogenization of the alloy takes place and a coarse plate-like α+intergranular β structure is found throughout the microstructure in temperatures above 1300 deg. C. The process variables were defined aiming to minimize interstitial pick-up (C, O, and N) and avoiding intensive grain growth

Investigation of microstructure in hot-pressed Nb–23Ti–15Al alloy

International Nuclear Information System (INIS)

Shi, Zhiwu; Wei, Hua; Zhang, Hongyu; Wu, Duoli; Jin, Tao; Sun, Xiaofeng; Zheng, Qi

2015-01-01

Highlights: • The Ti(O, C), a new strengthening phase, is found in Nb–Ti–Al alloys. • Ti(O, C) has a face-centered cubic structure and a lattice parameter of 4.27 Å. • Two different morphologies of Ti(O, C) are observed. • β and δ phases exhibit as large irregular blocks and equiaxed particles. • Ordering of β phase is observed in hot-pressed Nb–Ti–Al alloy. - Abstract: Microstructure of hot-pressed Nb–23Ti–15Al alloy has been systematically investigated, with emphasis on the characterization of Ti(O, C) phase. The microstructure and composition of Nb–23Ti–15Al alloy were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron probe microanalysis (EPMA). The results indicate the presence of β, δ and Ti(O, C) phases in the alloy. The β phase exhibits as large irregular blocks, while the δ phase presents as small equiaxed particles linked together around β blocks. Ordering of β phase is shown by related selected area electronic diffraction (SAED) patterns and dark-field micrograph. The Ti(O, C), a solid-solution of TiO or TiC, is characterized for the first time in Nb–Ti–Al alloy. The Ti(O, C) has a face-centered cubic (FCC) structure and a moderate lattice parameter between that of TiO and TiC. Two different morphologies of Ti(O, C) are observed in the alloy: large cobblestone-like aggregated particles and small dispersive particles. The formation of Ti(O, C) phase can potentially increase high-temperature strength of Nb–Ti–Al alloy

Investigation of microstructure in hot-pressed Nb–23Ti–15Al alloy

Energy Technology Data Exchange (ETDEWEB)

Shi, Zhiwu; Wei, Hua; Zhang, Hongyu; Wu, Duoli; Jin, Tao; Sun, Xiaofeng; Zheng, Qi, E-mail: qzheng@imr.ac.cn

2015-07-05

Highlights: • The Ti(O, C), a new strengthening phase, is found in Nb–Ti–Al alloys. • Ti(O, C) has a face-centered cubic structure and a lattice parameter of 4.27 Å. • Two different morphologies of Ti(O, C) are observed. • β and δ phases exhibit as large irregular blocks and equiaxed particles. • Ordering of β phase is observed in hot-pressed Nb–Ti–Al alloy. - Abstract: Microstructure of hot-pressed Nb–23Ti–15Al alloy has been systematically investigated, with emphasis on the characterization of Ti(O, C) phase. The microstructure and composition of Nb–23Ti–15Al alloy were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron probe microanalysis (EPMA). The results indicate the presence of β, δ and Ti(O, C) phases in the alloy. The β phase exhibits as large irregular blocks, while the δ phase presents as small equiaxed particles linked together around β blocks. Ordering of β phase is shown by related selected area electronic diffraction (SAED) patterns and dark-field micrograph. The Ti(O, C), a solid-solution of TiO or TiC, is characterized for the first time in Nb–Ti–Al alloy. The Ti(O, C) has a face-centered cubic (FCC) structure and a moderate lattice parameter between that of TiO and TiC. Two different morphologies of Ti(O, C) are observed in the alloy: large cobblestone-like aggregated particles and small dispersive particles. The formation of Ti(O, C) phase can potentially increase high-temperature strength of Nb–Ti–Al alloy.

Oxide formation and precipitation behaviors on interface of F82H steel joints during HIPing and hot pressing

International Nuclear Information System (INIS)

Kishimoto, H.; Ono, T.; Sakasegawa, H.; Tanigawa, H.; Ando, M.; Shibayama, T.; Kohno, Y.; Kohyama, A.

2013-01-01

Joining technologies for F82H steels are important issues for the development of fusion energy. The hot isostatic pressing (HIP) method is appropriate for consolidating the first wall of the blanket because of the flexibility of the shape of HIPed products. The HIP method is planned for fabricating a complex-shaped first wall component with built-in cooling channels; thus, accumulation of studies of microstructural and mechanical property changes, especially lower toughness of the HIPed joints, is essential. Present research aims to reveal the microstructural evolution of F82H joints fabricated by the HIP method compared with joints fabricated by hot pressing, focusing on the formation of oxides on the interface. F82H joints were characterized using 1/3-scale Charpy V-notch impact test, transmission electron microscope, scanning electron microscope, and electron probe analysis to survey the microstructural characteristics of the interface

Effects of hot isostatic pressing on the elastic modulus and tensile properties of 316L parts made by powder bed laser fusion

International Nuclear Information System (INIS)

Lavery, N.P.; Cherry, J.; Mehmood, S.; Davies, H.; Girling, B.; Sackett, E.; Brown, S.G.R.; Sienz, J.

2017-01-01

The microstructure and mechanical properties of 316L steel have been examined for parts built by a powder bed laser fusion process, which uses a laser to melt and build parts additively on a layer by layer basis. Relative density and porosity determined using various experimental techniques were correlated against laser energy density. Based on porosity sizes, morphology and distributions, the porosity was seen to transition between an irregular, highly directional porosity at the low laser energy density and a smaller, more rounded and randomly distributed porosity at higher laser energy density, thought to be caused by keyhole melting. In both cases, the porosity was reduced by hot isostatic pressing (HIP). High throughput ultrasound based measurements were used to calculate elasticity properties and show that the lower porosities from builds with higher energy densities have higher elasticity moduli in accordance with empirical relationships, and hot isostatic pressing improves the elasticity properties to levels associated with wrought/rolled 316L. However, even with hot isostatic pressing the best properties were obtained from samples with the lowest porosity in the as-built condition. A finite element stress analysis based on the porosity microstructures was undertaken, to understand the effect of pore size distributions and morphology on the Young's modulus. Over 1–5% porosity range angular porosity was found to reduce the Young's modulus by 5% more than rounded porosity. Experimentally measured Young's moduli for samples treated by HIP were closer to the rounded trends than the as-built samples, which were closer to angular trends. Tensile tests on specimens produced at optimised machine parameters displayed a high degree of anisotropy in the build direction and test variability for as-built parts, especially between vertical and horizontal build directions. The as-built properties were generally found to have a higher yield stress, but lower upper

Effects of hot isostatic pressing on the elastic modulus and tensile properties of 316L parts made by powder bed laser fusion

Energy Technology Data Exchange (ETDEWEB)

Lavery, N.P., E-mail: N.P.Lavery@swansea.ac.uk [Materials Research Centre, College of Engineering, Swansea University Bay Campus, Fabian Way, Swansea SA1 8EP (United Kingdom); Zienkiewicz Centre for Computational Engineering, College of Engineering, Swansea University Bay Campus, Fabian Way, Swansea SA1 8EP (United Kingdom); Cherry, J.; Mehmood, S. [Materials Research Centre, College of Engineering, Swansea University Bay Campus, Fabian Way, Swansea SA1 8EP (United Kingdom); Zienkiewicz Centre for Computational Engineering, College of Engineering, Swansea University Bay Campus, Fabian Way, Swansea SA1 8EP (United Kingdom); Davies, H. [Materials Research Centre, College of Engineering, Swansea University Bay Campus, Fabian Way, Swansea SA1 8EP (United Kingdom); Girling, B.; Sackett, E. [Materials Research Centre, College of Engineering, Swansea University Bay Campus, Fabian Way, Swansea SA1 8EP (United Kingdom); Zienkiewicz Centre for Computational Engineering, College of Engineering, Swansea University Bay Campus, Fabian Way, Swansea SA1 8EP (United Kingdom); Brown, S.G.R. [Materials Research Centre, College of Engineering, Swansea University Bay Campus, Fabian Way, Swansea SA1 8EP (United Kingdom); Sienz, J. [Zienkiewicz Centre for Computational Engineering, College of Engineering, Swansea University Bay Campus, Fabian Way, Swansea SA1 8EP (United Kingdom)

2017-05-02

The microstructure and mechanical properties of 316L steel have been examined for parts built by a powder bed laser fusion process, which uses a laser to melt and build parts additively on a layer by layer basis. Relative density and porosity determined using various experimental techniques were correlated against laser energy density. Based on porosity sizes, morphology and distributions, the porosity was seen to transition between an irregular, highly directional porosity at the low laser energy density and a smaller, more rounded and randomly distributed porosity at higher laser energy density, thought to be caused by keyhole melting. In both cases, the porosity was reduced by hot isostatic pressing (HIP). High throughput ultrasound based measurements were used to calculate elasticity properties and show that the lower porosities from builds with higher energy densities have higher elasticity moduli in accordance with empirical relationships, and hot isostatic pressing improves the elasticity properties to levels associated with wrought/rolled 316L. However, even with hot isostatic pressing the best properties were obtained from samples with the lowest porosity in the as-built condition. A finite element stress analysis based on the porosity microstructures was undertaken, to understand the effect of pore size distributions and morphology on the Young's modulus. Over 1–5% porosity range angular porosity was found to reduce the Young's modulus by 5% more than rounded porosity. Experimentally measured Young's moduli for samples treated by HIP were closer to the rounded trends than the as-built samples, which were closer to angular trends. Tensile tests on specimens produced at optimised machine parameters displayed a high degree of anisotropy in the build direction and test variability for as-built parts, especially between vertical and horizontal build directions. The as-built properties were generally found to have a higher yield stress, but

Development of oxide dispersion strengthened W alloys produced by hot isostatic pressing

International Nuclear Information System (INIS)

Martinez, J.; Savoini, B.; Monge, M.A.; Munoz, A.; Pareja, R.

2011-01-01

A powder metallurgy technique has been developed to produce oxide strengthened W-Ti and W-V alloys using elemental powders and nanosized powders of La 2 O 3 or Y 2 O 3 as starting materials. The alloys consolidated by hot isostatic pressing resulted in high-density materials having an ultrafine-grained structure and microhardness values in the range 7-13 GPa. Atom force microscopy studies show a topographic relief in the Ti and V pools that appear in the consolidated alloys. This relief is attributed to the heterogeneous nucleation of martensite plates. The preliminary transmission electron microscopy studies have revealed that a dispersion of nanoparticles can be induced in these alloys produced via the present technique.

THERMOELECTRIC PROPERTIES OF HOT-PRESSED p-TYPE Mg2Si0.3Sn0.7 SOLID SOLUTION

Directory of Open Access Journals (Sweden)

G. N. Isachenko

2014-05-01

Full Text Available It is shown that thermoelectric energy conversion which gives the possibility for utilizing a low potential heat is one of the ways for adoption of energy-saving technologies; and semiconductor materials with p-type and n-type conductivities having high thermoelectric figure of merit are necessary for operation of thermoelectric generators. The paper deals with possibility of usage of the p-Mg2Si0.3Sn0.7 solid solution (with a nanostructured modification as a couple for the well studied thermoelectric material based on n-Mg2Si-Mg2Sn. A technological scheme for fabrication of heavily doped Mg2Si0.3Sn0.7 solid solution of p-type by hot pressing from nanopowder is developed. The given technology has made it possible to reduce duration of a homogeneous material fabrication and has improved its physical and chemical properties. The samples were made by three ways: direct fusion for polycrystals fabrication; hot pressing from microparticles; nanostructuring, i.e. hot pressing from nanoparticles. By X-ray diffraction it is shown that sizes of structural elements in the fabricated samples are about 40 nm. The probe technique is used for measurement of electric conductivity and Seebeck coefficient. The stationary absolute method is used for measurement of thermal conductivity. Thermoelectric figure of merit is defined by measured values of kinetic coefficients in the temperatures range of 77 – 800 K. It was demonstrated, that electric conductivity, Seebeck coefficient and the power factor do not depend practically on a way of solid solution preparation. Thermal conductivity of samples pressed from nanoparticles has appeared to be higher, than of samples, obtained by direct fusion; i.e. in this case nanostructuring has not led to increase of thermoelectric figure of merit. The conclusion is drawn, that polycrystalline semiconductor Mg2Si0.3Sn0.7 can be used as a p-branch for a thermoelectric generator though nanostructuring has not led to the figure of

Texture studies of hot-pressed K2Pb4Nb10O30 ceramics

International Nuclear Information System (INIS)

Filip'ev, V.S.; Zav'yalov, V.P.; Bunina, O.A.; Gavrilyachenko, S.V.; Fesenko, E.G.

1984-01-01

An X-ray diffraction analysis was used to investigate the texture in sampl es of K 2 Pb 4 Nb 10 O 30 ferroelectric produced by powder hot pressing and sintering at 1370-1500 k. A spontaneous formation of the secondary texture during ferroelectric phase transformation was revealed. An important role of internal stresses in the secondary texture formation was supported. The ceramic s with a high-grade texture is noted to be characterized by a high anisotropy of dielectric and piezoelectric properties, its parameters approaching to those of a monocrystal

Void formation in ODS EUROFER produced by hot isostatic pressing

International Nuclear Information System (INIS)

Ortega, Y.; Monge, M.A.; Castro, V. de; Munoz, A.; Leguey, T.; Pareja, R.

2009-01-01

Positron annihilation experiments were performed on oxide dispersion strengthened (ODS) and non-ODS EUROFER prepared by mechanical alloying and hot isostatic pressing. The results revealed the presence of small voids in these materials in the as-HIPed conditions. Their evolution under isochronal annealing experiments was investigated. The coincidence Doppler broadening spectra of ODS EUROFER exhibited a characteristic signature attributed to positron annihilation in Ar-decorated voids at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature showed three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. In the temperature range 823-1323 K void coarsening had effect. Above 1323 K some voids annealed out, but others, associated to oxide particles and small precipitates, survived to annealing at 1523 K. Transmission electron microscopy observations were also performed to verify the characteristics of the surviving defects after annealing at 1523 K.

Void formation in ODS EUROFER produced by hot isostatic pressing

Energy Technology Data Exchange (ETDEWEB)

Ortega, Y. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)], E-mail: yanicet@fis.ucm.es; Monge, M.A. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Castro, V. de [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Munoz, A.; Leguey, T.; Pareja, R. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

2009-04-30

Positron annihilation experiments were performed on oxide dispersion strengthened (ODS) and non-ODS EUROFER prepared by mechanical alloying and hot isostatic pressing. The results revealed the presence of small voids in these materials in the as-HIPed conditions. Their evolution under isochronal annealing experiments was investigated. The coincidence Doppler broadening spectra of ODS EUROFER exhibited a characteristic signature attributed to positron annihilation in Ar-decorated voids at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature showed three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. In the temperature range 823-1323 K void coarsening had effect. Above 1323 K some voids annealed out, but others, associated to oxide particles and small precipitates, survived to annealing at 1523 K. Transmission electron microscopy observations were also performed to verify the characteristics of the surviving defects after annealing at 1523 K.

Microstructure, mechanical and tribological behavior of hot-pressed mechanically alloyed Al–Zn–Mg–Cu powders

International Nuclear Information System (INIS)

Azimi, A.; Fallahdoost, H.; Nejadseyfi, O.

2015-01-01

Highlights: • Nanocrystalline Al7050 alloy was synthesized by mechanical alloying. • Longer milling time led to increasing porosity in hot-pressed samples. • Significant improvement in strength and wear resistance was obtained by increasing the milling time up to 40 h. - Abstract: This research focuses on the preparation of Al7050 alloy via mechanical alloying and hot pressing techniques. The effect of milling time on the microstructure and densification response was investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). Furthermore, the mechanical properties of the samples including microhardness, compression strength, and wear resistance were examined as a function of milling time. The results of the experiments proved that by increasing the milling time the crystallite size was reduced, which has a significant effect on improving the mechanical properties. In addition, porosity formation increased when the milling time was increased due to reduction of the compressibility of finer particles. By increasing the milling time to more than 40 h, a relatively invariable crystallite size was obtained and it was observed that the porosities expanded in the samples. Therefore, the compressive strength, hardness, and wear resistance were enhanced up to 40 h milling time and then the strengthening effect was relatively diminished. On observing surfaces with SEM, the dominant wear mechanism was recognized as abrasion, delamination and adhesion

Effect of Temperature on the Fracture Toughness of Hot Isostatically Pressed 304L Stainless Steel

OpenAIRE

Cooper, Adam J.; Sherry, Andrew

2018-01-01

Herein, we have performed J-Resistance multi-specimen fracture toughness testing of hot isostatically pressed (HIP’d) and forged 304L austenitic stainless steel, tested at elevated (300 °C) and cryogenic (− 140 °C) temperatures. The work highlights that although both materials fail in a pure ductile fashion, stainless steel manufactured by HIP displays a marked reduction in fracture toughness, defined using J0.2BL, when compared to equivalently graded forged 304L, which is relatively constant...

Processing and properties of calcium phosphates bioceramics by hot isostatic pressing

Directory of Open Access Journals (Sweden)

Boilet Laurent

2013-11-01

Full Text Available Stoichiometric β-tricalcium phosphate (β-TCP, hydroxyapatite (HA and biphasic calcium phosphate (TCP/HA 60/40 %wt, BCP40 powders were synthesized by chemical precipitation of aqueous solutions of diammonium phosphate and calcium nitrate. After a calcination treatment and a milling step, powders were shaped by slip-casting. The sintering temperature effect on the density and the average grain size was investigated. By natural sintering, densities between 98 and 99.8% were obtained. Hot Isostatic Pressing (HIP treatment was carried out after a pre-sintering of these materials. Transparent or translucent samples were obtained, indicating a relative density very close to the theoretical value (>99.9%. Mechanical properties (three-point bending strength, fracture toughness, Young's modulus and Vickers hardness were measured on hipped materials with similar grain size (∼0.7μm.

Interface analysis of A1 matrix composites produced by hot isostatic pressing, squeeze casting and semi-solid processing

International Nuclear Information System (INIS)

Shamsul, J.B.; Zainal Arifin Ahmad; Faaizulaswad, M.S.; Azmi, R.

2000-01-01

The interface analysis has been carried out an aluminium based composites system produced by hot isostatic pressing, squeeze casting and semi-solid processing. A range of different fabrication techniques has been used to produce different types of microstructure of Al 2124 (Al-Cu-Mg) reinforced with 5 weight % SiC particles. Blending followed by hot isostatic pressing is used to fabricate composite I. Composite II was 6061 (Al-Si-Mg) wrought aluminium alloy reinforced with fibres of alumina-silica (V f = 0.58) and fabricated by squeeze casting. Finally, A356 (AlSi7Mg0.3) alloy was reinforced with 20 Vol.% of SiC particles (13 μm) and namely as composite III. Composite III is fabricated by semi-solid processing. Interface analysis was done by optical microscopy, scanning and transmission electron microscopy. Composite I exhibited good interface bonding and dislocation was also observed near the interface. Elements such as Al, Fe, Cr, Mn were found near the interface of composite II and intermetallic of iron rich inclusion and Mg 2 Si were observed near the interface of composite III. (Author)

Development of oxide dispersion strengthened W alloys produced by hot isostatic pressing

Energy Technology Data Exchange (ETDEWEB)

Martinez, J.; Savoini, B.; Monge, M.A. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Munoz, A., E-mail: angel.munoz@uc3m.es [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Pareja, R. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

2011-10-15

A powder metallurgy technique has been developed to produce oxide strengthened W-Ti and W-V alloys using elemental powders and nanosized powders of La{sub 2}O{sub 3} or Y{sub 2}O{sub 3} as starting materials. The alloys consolidated by hot isostatic pressing resulted in high-density materials having an ultrafine-grained structure and microhardness values in the range 7-13 GPa. Atom force microscopy studies show a topographic relief in the Ti and V pools that appear in the consolidated alloys. This relief is attributed to the heterogeneous nucleation of martensite plates. The preliminary transmission electron microscopy studies have revealed that a dispersion of nanoparticles can be induced in these alloys produced via the present technique.

Effect of Temperature on the Fracture Toughness of Hot Isostatically Pressed 304L Stainless Steel

Science.gov (United States)

Cooper, A. J.; Brayshaw, W. J.; Sherry, A. H.

2018-03-01

Herein, we have performed J- Resistance multi-specimen fracture toughness testing of hot isostatically pressed (HIP'd) and forged 304L austenitic stainless steel, tested at elevated (300 °C) and cryogenic (- 140 °C) temperatures. The work highlights that although both materials fail in a pure ductile fashion, stainless steel manufactured by HIP displays a marked reduction in fracture toughness, defined using J 0.2BL, when compared to equivalently graded forged 304L, which is relatively constant across the tested temperature range.

Silver as a highly effective bonding layer for lead telluride thermoelectric modules assembled by rapid hot-pressing

International Nuclear Information System (INIS)

Li, C.C.; Drymiotis, F.; Liao, L.L.; Dai, M.J.; Liu, C.K.; Chen, C.L.; Chen, Y.Y.; Kao, C.R.; Snyder, G.J.

2015-01-01

Highlights: • Ag serves as a promising bonding material for PbTe operating at T Hot ⩽ 400 °C. • The Ag foils reacted vigorously with PbTe to form Ag 2 Te at 550 °C. • The Seebeck coefficient of Ag/PbTe/Ag is slightly higher than that of pure PbTe. • A cost-effective way for long-term operations at high temperature. - Abstract: We use the rapid hot-pressing method to bond Ag foil onto pure PbTe in order to assess its effectiveness as a bonding layer material for thermoelectric module applications. Scanning electron microscopy and X-ray diffraction are employed to examine intermetallic compound formation and microstructure evolution during isothermal aging at 400 °C and 550 °C. We find that Ag is a promising bonding material for PbTe modules operating at T Hot ⩽ 400 °C. Additionally, our approach highlights a highly effective and inexpensive method to metallize PbTe prior to module assembly

FeCrAl and Zr alloys joined using hot isostatic pressing for fusion energy applications

International Nuclear Information System (INIS)

Park, Dong Jun; Kim, Hyun Gil; Park, Jeong Yong; Jung, Yang Il; Park, Jung Hwan; Koo, Yang Hyun

2016-01-01

Highlights: • FeCrAl and Zr alloys were successfully joined by hot isostatic pressing (HIP). • The thickness of diffusion layer increased with an increase in HIP temperature. • Significant inter-diffusion was observed for HIP at 1150 °C. • Maximum joint strength was achieved at HIP temperature of 700 °C. - Abstract: FeCrAl and Zr alloys were joined by a hot isostatic pressing (HIP) method for fusion energy applications. The optimum conditions for the joining process were studied. The HIP temperatures were varied from 700 to 1050 °C. The mechanical properties of the HIPed samples were evaluated by four-point bending and tensile tests. The FeCrAl and Zr alloys HIPed at 700 °C showed higher joint strength than the other samples. The joint strength decreased with an increase in the HIP temperature from 700 to 950 °C and significantly dropped at 1050 °C. Transmission electron microscopy, scanning electron microscopy, and optical microscopy were used to characterize the joints and interface region of the HIPed samples. The joints appeared to be tightly bonded and no intermetallic compounds or gaps were observed at the interface for HIP temperatures up to 950 °C. A diffusion layer formed at the interface and its thickness increased with the HIP temperature. HIP at 1050 °C, on the other hand, resulted in significant inter-diffusion and formation of brittle inter-metallic compounds at the interface.

Room temperature deformation mechanisms in ultrafine-grained materials processed by hot isostatic pressing

International Nuclear Information System (INIS)

Cao, W.Q.; Dirras, G.F.; Benyoucef, M.; Bacroix, B.

2007-01-01

Ultrafine-grained (uf-g) and microcrystalline-grained (mc-g) irons have been fabricated by hot isostatic pressing of nanopowders. The mechanical properties have been characterized by compressive tests at room temperature and the resulting microstructures and textures have been determined by combining electron back scatter diffraction and transmission electron microscopy. A transition of the deformation mode, from work hardening to work softening occurs for grain sizes below ∼1 μm, reflecting a transition of the deformation mode from homogeneous to localized deformation into shear bands (SBs). The homogeneous deformation is found to be lattice dislocation-based while the deformation within SBs involves lattice dislocations as well as boundary-related mechanisms, possibly grain boundary sliding accommodated by boundary opening

An Assessment of the Ductile Fracture Behaviour of Hot Isostatically Pressed and Forged 304L Stainless Steel

OpenAIRE

Cooper, Adam; Smith, R. J.; Sherry, Andrew

2017-01-01

Type 300 austenitic stainless steel manufactured by hot isostatic pressing (HIP) has recently been shown to exhibit subtly different fracture behavior from that of equivalent graded forged steel, whereby the oxygen remaining in the component after HIP manifests itself in the austenite matrix as nonmetallic oxide inclusions. These inclusions facilitate fracture by acting as nucleation sites for the initiation, growth, and coalescence of microvoids in the plastically deforming austenite matrix....

Influence of Sintering Temperature on the Microstructure and Mechanical Properties of In Situ Reinforced Titanium Composites by Inductive Hot Pressing

Directory of Open Access Journals (Sweden)

Cristina Arévalo

2016-11-01

Full Text Available This research is focused on the influence of processing temperature on titanium matrix composites reinforced through Ti, Al, and B4C reactions. In order to investigate the effect of Ti-Al based intermetallic compounds on the properties of the composites, aluminum powder was incorporated into the starting materials. In this way, in situ TixAly were expected to form as well as TiB and TiC. The specimens were fabricated by the powder metallurgy technique known as inductive hot pressing (iHP, using a temperature range between 900 °C and 1400 °C, at 40 MPa for 5 min. Raising the inductive hot pressing temperature may affect the microstructure and properties of the composites. Consequently, the variations of the reinforcing phases were investigated. X-ray diffraction, microstructural analysis, and mechanical properties (Young’s modulus and hardness of the specimens were carried out to evaluate and determine the significant influence of the processing temperature on the behavior of the composites.

Dynamic Failure and Fragmentation of a Hot-Pressed Boron Carbide

Science.gov (United States)

Sano, Tomoko; Vargas-Gonzalez, Lionel; LaSalvia, Jerry; Hogan, James David

2017-12-01

This study investigates the failure and fragmentation of a hot-pressed boron carbide during high rate impact experiments. Four impact experiments are performed using a composite-backed target configuration at similar velocities, where two of the impact experiments resulted in complete target penetration and two resulted in partial penetration. This paper seeks to evaluate and understand the dynamic behavior of the ceramic that led to either the complete or partial penetration cases, focusing on: (1) surface and internal failure features of fragments using optical, scanning electron, and transmission electron microscopy, and (2) fragment size analysis using state-of-the-art particle-sizing technology that informs about the consequences of failure. Detailed characterization of the mechanical properties and the microstructure is also performed. Results indicate that transgranular fracture was the primary mode of failure in this boron carbide material, and no stress-induced amorphization features were observed. Analysis of the fragment sizes for the partial and completely penetrated experiments revealed a possible correlation between larger fragment sizes and impact performance. The results will add insight into designing improved advanced ceramics for impact protection applications.

Improvement of linerboard compressive strength by hot-pressing and addition of recovered lignin from spent pulping liquor

Directory of Open Access Journals (Sweden)

Saidan Motasem N.

2015-01-01

Full Text Available This paper evaluates the effect of addition of precipitated lignin, from spent pulping black liquor, to a wet single-ply linerboard handsheet followed by hot-pressing at different temperatures, on the improvement of its compressive strength. Linerboard handsheets for testing the effect of lignin addition were prepared so that the lignin-modified sheets would have the same basis weights as the control handsheets. Both the commercial and the black liquor lignin were added as a powder to wet handsheets after couching from the handsheet mold. The experiments and testing of the physical and strength properties of dried handsheets were conducted according to TAPPI test methods. The results revealed that the addition of the recovered lignin (at pH of 2 to the wet handsheet followed by hot-pressing at 150°C increased the compressive strength of linerboard handsheets by 10% to 20% above that for handsheets made without the addition of lignin. The same results were achieved using purchased lignin. However, with a 16% addition to linerboard, purchased lignin would be too expensive. These results indicate that inclusion of kraft lignin in linerboard sheets could be proved as an attractive option to reduce linerboard basis weight.

An Assessment of the Ductile Fracture Behavior of Hot Isostatically Pressed and Forged 304L Stainless Steel

Science.gov (United States)

Cooper, A. J.; Smith, R. J.; Sherry, A. H.

2017-05-01

Type 300 austenitic stainless steel manufactured by hot isostatic pressing (HIP) has recently been shown to exhibit subtly different fracture behavior from that of equivalent graded forged steel, whereby the oxygen remaining in the component after HIP manifests itself in the austenite matrix as nonmetallic oxide inclusions. These inclusions facilitate fracture by acting as nucleation sites for the initiation, growth, and coalescence of microvoids in the plastically deforming austenite matrix. Here, we perform analyses based on the Rice-Tracey (RT) void growth model, supported by instrumented Charpy and J-integral fracture toughness testing at ambient temperature, to characterize the degree of void growth ahead of both a V-notch and crack in 304L stainless steel. We show that the hot isostatically pressed (HIP'd) 304L steel exhibits a lower critical void growth at the onset of fracture than that observed in forged 304L steel, which ultimately results in HIP'd steel exhibiting lower fracture toughness at initiation and impact toughness. Although the reduction in toughness of HIP'd steel is not detrimental to its use, due to the steel's sufficiently high toughness, the study does indicate that HIP'd and forged 304L steel behave as subtly different materials at a microstructural level with respect to their fracture behavior.

The influence of powder composition and sintering temperature on transformation kinetics, structure and mechanical properties of hot-pressed silicon nitride

International Nuclear Information System (INIS)

Knoch, H.; Ziegler, G.

1977-01-01

The strength at room temperature of hot-pressed silicon nitride is strongly dependent on the structure which in turn depends on powder composition and process parameters. Connections between production conditions (MgO content, pressing temperature, pressing time), structure (α/β content and morphology), and the properties at room temperature are discussed. The growth of oblong β grains - as a direct result of phase transition from α- to β-Si 3 N 4 - results in microstructural meshing and thus in a higher strength. Optimum mechanical properties are achieved after full phase transformation and with a microstructure as fine as possible. The direct connection between strength and transformed β fraction indicates a possible way for a relatively fast determination of optimum properties for a given initial powder. (orig.) [de

Characteristics of hot-pressed fiber-reinforced ceramics with SiC matrix

Science.gov (United States)

Miyoshi, Tadahiko; Kodama, Hironori; Sakamoto, Hiroshi; Goto, Akihiro; Iijima, Shiroo

1989-11-01

Silicon carbide ceramics’ matrix composites with SiC or C filaments were fabricated through hot pressing, and the effects of the filament pullout on their fracture toughness were experimentally investigated. The C-rich coating layers on the SiC filaments were found to have a significant effect on the frictional stress at the filament/matrix interfaces, through assising the filamet pullout from the matrix. Although the coating layers were apt to burn out in the sintering process of SiC matrix compposites, a small addition of carbon to the raw materials was found to be effective for the retention of the layers on the fibers, thus increasing the fracture toughness of the composites. The fracture toughness of the C filament/SiC matrix composite increased with temperature due to the larger interfacial frictional stress at higher temperatures, because of the higher thermal expansion of the filament in the radial direction than that of the matrix.

Hot-pressed silicon nitride with various lanthanide oxides as sintering additives

Science.gov (United States)

Ueno, K.; Toibana, Y.

1984-01-01

The effects of addition of various lanthanide oxides and their mixture with Y2O3 on the sintering of Si3N4 were investigated. The addition of simple and mixed lanthanide oxides promoted the densification of Si3N4 in hot-pressing at 1800 C under 300-400kg/ centimeters squared for 60 min. The crystallization of yttrium and lanthanide-silicon oxynitrides which was observed inn the sintered body containing yttrium-lanthanide mixed oxides as additives led to the formation of a highly refractory Si3N4 ceramic having a bending strength of 82 and 84 kg/millimeters squared at room temperature and 1300 C respectively. In a Y2O3+La2O3 system, a higher molar ratio of La2O3 to Y2O3 gave a higher hardness and strength at high temperatures. It was found that 90 min was an optimum sintering time for the highest strength.

Yb:Y2O3 transparent ceramics processed with hot isostatic pressing

Science.gov (United States)

Wang, Jun; Ma, Jie; Zhang, Jian; Liu, Peng; Luo, Dewei; Yin, Danlei; Tang, Dingyuan; Kong, Ling Bing

2017-09-01

Highly transparent 5 at.% Yb:Y2O3 ceramics were fabricated by using a combination method of vacuum sintering and hot isostatic pressing (HIP). Co-precipitated Yb:Y2O3 powders, with 1 at.% ZrO2 as the sintering aid, were used as the starting material. The Yb:Y2O3 ceramics, vacuum sintered at 1700 °C for 2 h and HIPed at 1775 °C for 4 h, exhibited small grain size of 1.9 μm and highly dense microstructure. In-line optical transmittance of the ceramics reached 83.4% and 78.9% at 2000 and 600 nm, respectively. As the ceramic slab was pumped by a fiber-coupled laser diode at about 940 nm, a maximum output power of 0.77 W at 1076 nm was achieved, with a corresponding slope efficiency of 10.6%.

Importance of Electrode Hot-Pressing Conditions for the Catalyst Performance of Proton Exchange Membrane Fuel Cells

DEFF Research Database (Denmark)

Andersen, Shuang Ma; Dhiman, Rajnish; Larsen, Mikkel Juul

2015-01-01

The catalyst performance in a proton exchange membrane fuel cell (PEMFC) depends on not only the choice of materials, but also on the electrode structure and in particular on the interface between the components. In this work, we demonstrate that the hot-pressing conditions used during electrode...... lamination have a great influence on the catalyst properties of a low-temperature PEMFC, especially on its durability. Lamination pressure, temperature and duration were systematically studied in relation to the electrochemical surface area, platinum dissolution, platinum particle size and electrode surface...

Transformation of Cs-IONSIV® into a ceramic wasteform by hot isostatic pressing

Science.gov (United States)

Chen, Tzu-Yu; Maddrell, Ewan R.; Hyatt, Neil C.; Gandy, Amy S.; Stennett, Martin C.; Hriljac, Joseph A.

2018-01-01

A simple method to directly convert Cs-exchanged IONSIV® IE-911 into a ceramic wasteform by hot isostatic pressing (1100 °C/190 MPa/2 hr) is presented. Two major Cs-containing phases, Cs2TiNb6O18 and Cs2ZrSi6O15, and a series of mixed oxides form. The microstructure and phase assemblage of the samples as a function of Cs content were examined using XRD, XRF, SEM and TEM/EDX. The chemical aqueous durability of the materials was investigated using the MCC-1 and PCT-B standard test methods. For HIPed Cs-IONSIV® samples, the MCC-1 normalised release rates of Cs were low rates are indicative of a safe long-term immobilisation matrix for Cs formed directly from spent IONSIV®. It was also demonstrated that the phase formation can be altered by adding Ti metal due to a controlled redox environment.

Manufacturing and mechanical property test of the large-scale oxide dispersion strengthened martensitic mother tube by hot isostatic pressing and hot extrusion process

International Nuclear Information System (INIS)

Narita, Takeshi; Ukai, Shigeharu; Kaito, Takeji; Ohtsuka, Satoshi; Fujiwara, Masayuki

2003-09-01

Mass production capability of Oxide Dispersion Strengthened (ODS) ferritic steel cladding (9Cr) is evaluated in the Phase II of the Feasibility Studies on Commercialized Fast Reactor Cycle System. The cost for manufacturing mother tube is a dominant factor in the total cost for manufacturing ODS ferritic cladding. In this study, the large-scale 9Cr-ODS martensitic mother tube was produced by overseas supplier with mass production equipments for commercialized ODS steels. The process of manufacturing the ODS mother tube consists of raw material powder production, mechanical alloying by high energy ball mill, hot isostatic pressing(HIP), and hot extrusion. Following results were obtained in this study. (1) Micro structure of the ODS steels is equivalent to that of domestic products, and fine oxides are uniformly distributed. The mechanical alloying by large capacity (1 ton) ball mill can be satisfactorily carried out. (2) A large scale mother tube (65 mm OD x 48 mm ID x 10,000 mm L), which can produce about 60 pieces of 3 m length ODS ferritic claddings by four times cold rolling, have been successfully manufactured through HIP and Hot Extrusion process. (3) Rough surface of the mother tubes produced in this study can be improved by selecting the reasonable hot extrusion condition. (4) Hardness and tensile strength of the manufactured ODS steels are lower than domestic products with same chemical composition. This is owing to the high aluminum content in the product, and those properties could be improved by decreasing the aluminum content in the raw material powder. (author)

Development of Be/Glidcop joint obtained by hot isostatic pressing diffusion bonding for high in-service temperature

Energy Technology Data Exchange (ETDEWEB)

Saint-Antonin, F.; Bucci, P.; Burlet, H.; Le Marois, G. [CEA Centre d`Etudes de Grenoble, 38 (France); Barberi, D.; Laille, A.

1998-01-01

This paper addresses some aspects of the beryllium-Glidcop joining by Hot Isostatic Pressing diffusion Bonding. The quality of a joint is mainly dependent on the interface microstructure. Thus, as Be/copper direct bonding is not recommended, the choice of interlayers is a critical point. The joining process parameters, i.e. temperature, pressure and time, must take into account the in-service requirements, the mechanical and metallurgical properties of each material. The Be/Glidcop joining process developed at CEA/Grenoble is presented here. (author)

Transfer of microstructure pattern of CNTs onto flexible substrate using hot press technique for sensing applications

International Nuclear Information System (INIS)

Mishra, Prabhash; Tai, Nyan-Hwa; Harsh; Islam, S.S.

2013-01-01

Graphical abstract: - Highlights: • Successfully transfer of microstructure patterned CNTs on PET substrate. • Demonstrate as resistor-based NH 3 gas sensor in the sub-ppm range. • Excellent photodetector having instantaneous response and recovery characteristics. • An effective technique to grow and produce flexible electronic device. - Abstract: In this work, we report the successful and efficient transfer process of two- dimensional (2-D) vertically aligned carbon nanotubes (CNTs) onto polyethylene terephthalate (PET) substrate by hot pressing method with an aim to develop flexible sensor devices. Carbon nanotubes are synthesized by cold wall thermal chemical vapor deposition using patterned SiO 2 substrate under low pressure. The height of the pattern of CNTs is controlled by reaction time. The entire growth and transfer process is carried out within 30 min. Strong adhesion between the nanotube and polyethylene terephthalate substrate was observed in the post-transferred case. Raman spectroscopy and scanning electron microscope (SEM) studies are used to analyze the microstructure of carbon nanotube film before and after hot pressing. This technique shows great potential for the fabrication of flexible sensing devices. We report for the first time, the application of patterned microstructure developed by this technique in the development of gas sensor and optoelectronic device. Surface resistive mode is used for detection of ammonia (NH 3 ) gas in the sub-ppm range. An impressive photoconducting response is also observed in the visible wavelength. The reproducibility of the sample was checked and the results indicate the possibility of use of carbon nanotube as gas sensor, photodetector, CCDs etc

Transfer of microstructure pattern of CNTs onto flexible substrate using hot press technique for sensing applications

Energy Technology Data Exchange (ETDEWEB)

Mishra, Prabhash [Department of Material Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Nano-Sensor Research Laboratory, F/O Engineering and Technology, Jamia Millia Islamia, Jamia Nagar, New Delhi (India); Tai, Nyan-Hwa [Department of Material Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Harsh [Nano-Sensor Research Laboratory, F/O Engineering and Technology, Jamia Millia Islamia, Jamia Nagar, New Delhi (India); Islam, S.S., E-mail: safiul5996@gmail.com [Nano-Sensor Research Laboratory, F/O Engineering and Technology, Jamia Millia Islamia, Jamia Nagar, New Delhi (India)

2013-08-01

Graphical abstract: - Highlights: • Successfully transfer of microstructure patterned CNTs on PET substrate. • Demonstrate as resistor-based NH{sub 3} gas sensor in the sub-ppm range. • Excellent photodetector having instantaneous response and recovery characteristics. • An effective technique to grow and produce flexible electronic device. - Abstract: In this work, we report the successful and efficient transfer process of two- dimensional (2-D) vertically aligned carbon nanotubes (CNTs) onto polyethylene terephthalate (PET) substrate by hot pressing method with an aim to develop flexible sensor devices. Carbon nanotubes are synthesized by cold wall thermal chemical vapor deposition using patterned SiO{sub 2} substrate under low pressure. The height of the pattern of CNTs is controlled by reaction time. The entire growth and transfer process is carried out within 30 min. Strong adhesion between the nanotube and polyethylene terephthalate substrate was observed in the post-transferred case. Raman spectroscopy and scanning electron microscope (SEM) studies are used to analyze the microstructure of carbon nanotube film before and after hot pressing. This technique shows great potential for the fabrication of flexible sensing devices. We report for the first time, the application of patterned microstructure developed by this technique in the development of gas sensor and optoelectronic device. Surface resistive mode is used for detection of ammonia (NH{sub 3}) gas in the sub-ppm range. An impressive photoconducting response is also observed in the visible wavelength. The reproducibility of the sample was checked and the results indicate the possibility of use of carbon nanotube as gas sensor, photodetector, CCDs etc.

Phase transitions to 120 GPa for shock-compressed pyrolytic and hot-pressed boron nitride

International Nuclear Information System (INIS)

Gust, W.H.; Young, D.A.

1977-01-01

Shock-compression characteristics of two types of hexagonal graphitelike boron nitride have been investigated. Highly oriented very pure pyrolytic boron nitride exhibits shock-velocity versus particle-velocity discontinuities that appear to be manifestations of the initiation of a sluggish phase transition. This transition begins at 20 GPa and is driven to completion (melting) at 75 GPa. Discontinuities in the plot for impure hot-pressed boron nitride indicate initiation at 10 GPa and completion at 20 GPa. The (U/sub s/, U/sub p/) plots follow essentially the same paths for 4.0 < U/sub p/ < 5.2 km/sec. No evidence for a transition to a metalliclike state was seen. Temperature calculations indicate that the material is liquid above approx.80 GPa

Pore annihilation in a single-crystal nickel-base superalloy during hot isostatic pressing: Experiment and modelling

International Nuclear Information System (INIS)

Epishin, Alexander; Fedelich, Bernard; Link, Thomas; Feldmann, Titus; Svetlov, Igor L.

2013-01-01

Pore annihilation during hot isostatic pressing (HIP) was investigated in the single-crystal nickel-base superalloy CMSX-4 experimentally by interrupted HIP tests at 1288 °C/103 MPa. The kinetics of pore annihilation was determined by density measurement and quantitative metallography. Transmission electron microscopy of a HIPed specimen showed that the pores shrink via dislocation movement on octahedral glide planes. Theoretically pore closure under HIP condition was modelled by the finite element method using crystal plasticity and large strain theories. The modelling gives a similar kinetics of pore annihilation as observed experimentally, however somewhat higher annihilation rate

Mechanical properties of hot-pressed SiC-TiC composites

Directory of Open Access Journals (Sweden)

Kamil Kornaus

2017-12-01

Full Text Available SiC-TiC composites, with 0, 5, 10 and 20 vol.% of TiC, were sintered by the hot-pressing technique at temperature of 2000 °C under argon atmosphere. SiC sintering process was activated by liquid phase created by the reaction between Al2O3 and Y2O3, in which it is possible to dissolve passivating oxide layers (SiO2 and TiO2 and partially SiC and TiC carbides. Microstructure observation and density measurements confirmed that the composites were dense with uniformly distributed components. Differences in thermal expansion coefficients between SiC and TiC led to complex stress state occurrence. These stresses combined with the liquid-derived separate phase between grains boundaries increased fracture toughness of the composites, which ranged from 5.8 to 6.3 MPa·m0.5. Opposite to the bending strength, fracture toughness increased with the TiC volume fraction. By means of simulation of residual thermal stresses in the composites, it was found that with the increasing volume fraction of TiC, tensile stress in TiC grains is reduced simultaneously with strong rise of compressive stresses in the matrix.

Hot Press as a Sustainable Direct Recycling Technique of Aluminium: Mechanical Properties and Surface Integrity.

Science.gov (United States)

Yusuf, Nur Kamilah; Lajis, Mohd Amri; Ahmad, Azlan

2017-08-03

Meltless recycling technique has been utilized to overcome the lack of primary resources, focusing on reducing the usage of energy and materials. Hot press was proposed as a novel direct recycling technique which results in astoundingly low energy usage in contrast with conventional recycling. The aim of this study is to prove the technical feasibility of this approach by characterizing the recycled samples. For this purpose, AA6061 aluminium chips were recycled by utilizing hot press process under various operating temperature (T s = 430, 480, and 530 °C) and holding times (t s = 60, 90, and 120 min). The maximum mechanical properties of recycled chip are Ultimate tensile strength (UTS) = 266.78 MPa, Elongation to failure (ETF) = 16.129%, while, for surface integrity of the chips, the calculated microhardness is 81.744 HV, exhibited at T s = 530 °C and t s = 120 min. It is comparable to theoretical AA6061 T4-temper where maximum UTS and microhardness is increased up to 9.27% and 20.48%, respectively. As the desired mechanical properties of forgings can only be obtained by means of a final heat treatment, T5-temper, aging after forging process was employed. Heat treated recycled billet AA6061 (T5-temper) are considered comparable with as-received AA6061 T6, where the value of microhardness (98.649 HV) at 175 °C and 120 min of aging condition was revealed to be greater than 3.18%. Although it is quite early to put a base mainly on the observations in experimental settings, the potential for significant improvement offered by the direct recycling methods for production aluminium scrap can be clearly demonstrated. This overtures perspectives for industrial development of solid state recycling processes as environmentally benign alternatives of current melting based practices.

Nanostructured Al–Zn–Mg–Cu–Zr alloy prepared by mechanical alloying followed by hot pressing

International Nuclear Information System (INIS)

Azimi, Amin; Shokuhfar, Ali; Zolriasatein, Ashkan

2014-01-01

Nanostructured Al–7.8 wt% Zn–2.6 wt% Mg–2 wt% Cu–0.1 wt% Zr alloy was mechanically alloyed (MA) from elemental powders and consolidated by hot press technique. The effect of the milling time and hot pressing process on microstructure was investigated by means of X-ray diffraction measurements (XRD) and analytical and scanning electron microscopy (SEM). Furthermore mechanical properties of samples with different MA time as well as pure aluminum were investigated by microhardness and compression tests. The results show that an Al–Zn–Mg–Cu–Zr homogenous supersaturated solid solution with a crystallite size of 27 nm was obtained after 40 h of milling time. Microstructure refinement and morphological changes of powders from flake to spherical shape were observed by increasing milling time. Phase and microstructural characterization of high density bulk nanostructured samples revealed that increasing milling time up to 40 h leads to formation of MgZn 2 precipitation in the alloy matrix. With increasing milling time, density of the samples and crystalline size decrease. Significant enhancement of hardness and compressive strength is observed in the aluminum alloy by increasing milling time up to 40 h which is much higher than pure aluminum. Crystallite size refinement in pure aluminum samples from micro- to nanoscales resulted in 107% and 100% improvement in compressive strength and hardness, respectively. Furthermore the compressive strength and hardness of Al–Zn–Mg–Cu–Zr alloy nanostructured samples increased to 179% and 172%, respectively, compared to nanostructured pure Al, which was produced as reference specimen. 40 h of MA was the optimum case for preparing such an Al alloy and more milling up to 50 h led to deterioration of mechanical properties

Hot-isostatic pressing of U-10Zr by grain boundary diffusion and creep cavitation. Part 2: Theory and data analysis

International Nuclear Information System (INIS)

McDeavitt, S.M.; Solomon, A.A.

1997-01-01

Uranium-10 wt % zirconium (U-10Zr) is a fuel alloy that has been used in the Experimental Breeder Reactor-II (EBR-II). The high burnup that was desired in this fuel system made high demands on the mechanical compatibility between fuel and cladding both during normal operation and during safety-related transients when rapid differential expansion may cause high stresses. In general, this mechanical stress can be reduced by cladding deformation if the cladding is sufficiently ductile at high burnup, and/or by fuel hot-pressing. Fortunately, the fuel is very porous when it contacts the cladding, but this porosity gradually fills with solid fission products (primarily lanthanides) that may limit the fuel's compressibility. If the porosity remains open, gaseous fission products are released and the porous fuel creeps rather than hot-presses under contact stresses. If the pores are closed by sintering or by solid fission products, the porous fuel will hot-isostatic press (HIP), as represented by the models to be discussed. HIP experiments performed at 700 C on U-10Zr samples with different impurity phase contents (Part 1) are analyzed in terms of several creep cavitation models. The coupled diffusion/creep cavitation model of Chen and Argon shows good quantitative agreement with measured HIP rates for hydride- and metal-derived U-10Zr materials, assuming that pores are uniformly distributed on grain boundaries and are of modal size, and that far-field strain rates are negligible. The analysis predicts, for the first time, an asymmetry between HIP and swelling at identical pressure-induced driving forces due to differences in grain boundary stresses. The differences in compressibility of hydride- and metal-derived U-10Zr can be partially explained by differences in pore size and spacing. The relevance of the experiments to description of in-reactor densification under external pressure or contact stress due to fuel/cladding mechanical interaction is discussed

Interface characteristic during bonding of Be and HR-1 stainless steel by hot pressing

International Nuclear Information System (INIS)

Li Hui; Kang Renmu; Zhou Shangqi; Kong Jilan; Zhang Pengcheng

2010-01-01

Be and HR-I stainless steel was diffusion bonded by hot pressing. The microstructure,composition and phase distribution and mechanical properties of the joints were analyzed using the optical microscopy, scanning electron microscopy(SEM), scanning auger microspectroscopy(SAM) and x-ray diffraction(XRD), and the effect of different interlayer materials Cu and Al and Ag-Cu alloy was also discussed. The results show that it is not easy to joint Be and HR-1 stainless when Al was used as the interlayer material, but good joints can be obtained using Cu and Ag and Cu alloy as the interlayer materials, because the formation of Be-Fe brittle intermetallic compounds was prevented. Ag-Cu alloy is the best interlayer materials among them, as it can reduce the mutual diffusion between Be and Fe. (authors)

Microstructures and mechanical properties of Fe-28Al-5Cr/TiC composites produced by hot-pressing sintering

International Nuclear Information System (INIS)

Zhang Xinghua; Yang Jun; Ma Jiqiang; Bi Qinling; Cheng Jun; Liang Yongmin; Liu Weimin

2011-01-01

Highlights: → The near fully dense Fe-28Al-5Cr/TiC composites are produced by hot-pressing sintering. → All the materials exhibit high compressive and bending strength. → Compressive strength increases but bending strength and ductility diminish with rising TiC amount in the composites. → Wear resistance significantly increases with rising TiC amount. - Abstract: The mechanical properties and microstructures of Fe-28Al-5Cr based composites reinforced with 15, 25, 35, 50 wt.% TiC ceramic particle, produced by hot-pressing sintering method, were investigated. The relative density of all the composites was up to 99%. The distribution of TiC was uniform in the composites. Results of XRD analysis showed that the composites were composed of TiC and disorder Fe 3 Al phases. All the materials exhibited very high strength of 1200-2000 MPa. The hardness and compressive strength of the composites increased obviously but compressive strain decreased gradually except 50% composite with increasing TiC content. The bending strength and deflection of the composites decreased significantly with increasing TiC content. The bending fracture surfaces of all the materials were examined using scanning electron microscopy (SEM). The fracture mode transformed gradually from tough dimple fracture mode to brittle cleavage facets crack mode with the increase of TiC content. Wear resistance of the Fe-28Al-5Cr alloy was also significantly improved by addition of TiC.

Corrosion and wear behavior of functionally graded Al2024/SiC composites produced by hot pressing and consolidation

Energy Technology Data Exchange (ETDEWEB)

Erdemir, Fatih; Canakci, Aykut, E-mail: aykut@ktu.edu.tr; Varol, Temel; Ozkaya, Serdar

2015-09-25

Highlights: • Functionally graded Al2024/SiC composites were produced by hot pressing. • Effect of the number of graded layers was investigated on the corrosion behavior. • Functionally graded composites has the most corrosion resistant than composites. • Wear mechanisms of Al2024/SiC composites were explained. - Abstract: Functionally graded Al2024/SiC composites (FGMs) with varying percentage of SiC (30–60%) were produced by hot pressing and consolidation method. The effects of SiC content and number of layers of Al2024/SiC FGMs on the corrosion and wear behaviors were investigated. The microstructures of these composites were characterized by a scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). The corrosion performances of composites were evaluated by potentiodynamic polarization scans in 3.5% NaCl solution. Corrosion experiments shows that corrosion rate (1109 mpy) of two layered FGMs which containing 50 wt.% SiC were much higher than Al2024 matrix (2569 mpy) and Al2024/50 wt.% SiC composite (2201 mpy). Mechanical properties of these composites were evaluated by microhardness measurements and ball-on-disk wear tests. As the applied load change from 15 to 20 N, the wear rates of the Al2024 increased significantly and wear mechanism transformed from mild to severe wear regime. It has been shown that Al2024/40 wt.% SiC composite has lower wear rate where adhesive and abrasive wear mechanisms play a major role.

Hot radial pressing: An alternative technique for the manufacturing of plasma-facing components

International Nuclear Information System (INIS)

Visca, E.; Libera, S.; Mancini, A.; Mazzone, G.; Pizzuto, A.; Testani, C.

2005-01-01

The Hot radial pressing (HRP) manufacturing technique is based on the radial diffusion bonding principle performed between the cooling tube and the armour tile. The bonding is achieved by pressurizing the cooling tube while the joining interface is kept at the vacuum and temperature conditions. This technique has been used for the manufacturing of relevant mock-ups of the ITER divertor vertical target. Tungsten monoblock mock-ups were successfully tested to high heat flux thermal fatigue (20 MW/m 2 of absorbed heat flux for 1000 cycles). After these good results the activity is now focused on the developing of a manufacturing process suitable also for the CFC monoblock mock-ups. A FE calculation was performed to investigate the stress involved in the CFC tiles during the process and to avoid the CFC fracture. The results obtained by the FE calculation and by the test performed in air simulating a HRP manufacturing process for a CFC monoblock mock-ups is reported in the paper

TEM study of a hot-pressed Al2O3-NbC composite material

Directory of Open Access Journals (Sweden)

Wilson Acchar

2005-03-01

Full Text Available Alumina-based composites have been developed in order to improve the mechanical properties of the monolithic matrix and to replace the WC-Co material for cutting tool applications. Al2O3 reinforced with refractory carbides improves hardness, fracture toughness and wear resistance to values suitable for metalworking applications. Al2O3-NbC composites were uniaxially hot-pressed at 1650 °C in an inert atmosphere and their mechanical properties and microstructures were analyzed. Sintered density, average grain size, microhardness and fracture toughness measurements and microstructural features were evaluated. Results have shown that the mechanical properties of alumina-NbC are comparable to other carbide systems. Microstructural analysis has shown that the niobium carbide particles are mainly located at the grain boundaries of alumina grains, which is an evidence of the "pinning effect", produced by NbC particles.

Characterization of 316L(N)-IG SS joint produced by hot isostatic pressing technique

International Nuclear Information System (INIS)

Nakano, J.; Miwa, Y.; Tsukada, T.; Kikuchi, M.; Kita, S.; Nemoto, Y.; Tsuji, H.; Jitsukawa, S.

2002-01-01

Type 316L(N) stainless steel of the international thermonuclear experimental reactor grade (316L(N)-IG SS) is being considered for the first wall/blanket module. Hot isostatic pressing (HIP) technique is expected for the fabrication of the module. To evaluate the integrity and susceptibility to stress corrosion cracking (SCC) of HIPed 316L(N)-IG SS, tensile tests in vacuum and slow strain rate tests in high temperature water were performed. Specimen with the HIPed joint had similar tensile properties to specimens of 316L(N)-IG SS, and did not show susceptibility to SCC in oxygenated water at 423 K. Thermally sensitized specimen was low susceptible to SCC even in the creviced condition. It is concluded that the tensile properties of HIPed SS are as high as those of the base alloy and the HIP process caused no deleterious effects

Effects of internal gas pressure and microstructure on the mechanisms of hot-pressing and swelling in ceramics. Progress report, June 1, 1976--March 31, 1977

International Nuclear Information System (INIS)

Solomon, A.A.

1977-02-01

The low temperature isostatic pressurization system has been completed, operated successfully and calibrated. The new high temperature TD tungsten vessel and MoSi 2 element furnace system has also been designed and is presently under construction. Porous CoO single crystals have been grown using a ''skull melting'' process. Automated quantitative microscopy techniques are being developed using the KONTRON system to examine porosity evaluation during hot-pressing and sintering. Initial sintering experiments under variable isostatic pressures from 100 μm Hg to 2000 psi reveal no significant effect of ambient pressure. Nor were differences observed in sintering kinetics when either Helium or Argon were used as the pressurizing gas. Swelling experiments, conducted by reducing the ambient pressure after pore closure, revealed dramatic changes in density. The densification rates also appeared to depend on history, suggesting that mechanical deformation may play a dominant role in hot-pressing, at least during transients

The Novel Design and Manufacturing Technology of Densified RDF from Reclaimed Landfill without a Mixing Binding Agent Using a Hydraulic Hot Pressing Machine

Directory of Open Access Journals (Sweden)

Kerdsuwan Somrat

2016-01-01

Full Text Available The manufacturing of RDF (Refuse Derived Fuel from a conventional cold press extrusion machine is not suitable for producing RDF from reclaimed landfill since it is not identical in shape and form after production due to the swelling of the plastic fraction contained inside the reclaimed landfill and hence needs a very high compression force. Moreover, a binder agent is needed in order to keep the RDF in a similar shape and form. A novel design and manufacturing technology for a hydraulic hot pressing machine has been established and can produce high-quality RDF without any binder. The two electrical heaters are installed at the inner core and on the surface of the mold. The compression force on the mold is performed by a hydraulic jack. In addition, a newly-designed locking plate system which is designed by a slider to open and close along the paired horizontal slots, can reduce the cycle time of the manufacturing process and yield higher productivity. The testing properties of the RDF produced by the novel hydraulic hot pressing machine include the examination of size, shape, weight, unit density, bulk density, compression strength, moisture content, and heating value. The results showed that the RDF is suitable to be used as feedstock in an incinerator or gasifier to produce green and clean energy from reclaimed landfill.

Optimizing the Synthesis of Alumina Inserts Using Hot Isostatic Pressing (HIP)

Science.gov (United States)

Ariff, T. F.; Azhar, A. Z.; Sariff, M. N.; Rasid, S. N.; Zahari, S. Z.; Bahar, R.; Karim, M.; Nurul Amin, AKM

2018-01-01

Alumina or Aluminium Oxide (Al2O3) is well known for its high strength and hardness. Its low heat retention and low specific heat characteristics make it attractive to be used widely as a cutting tool for grinding, milling and turning processes. Various synthesis methods have been used for the purpose of enhancing the properties of the alumina inserts. However, the optimization process using Hot Isostatic Pressing (HIP) has not been performed. This research aims in finding the optimum parameters in synthesizing the alumina inserts (98Al2O3 1.6ZrO2 0.4MgO, 93Al2O3 6.4ZrO2 0.6MgO and 85Al2O3 14.5ZrO2 0.5MgO) using HIP at different temperatures (1200, 1250 and 1300°C) and sintering time (10, 30 and 60 minutes). Hardness, density, shrinkage and microstructure using SEM were analysed. The optimum sintering condition for the alumina insert was found in 98Al2O3 1.6ZrO2 0.4MgO sintered at 1300°C for 60 minutes for it exhibited the highest values of hardness (1917HV), density (3.95g/cm3), shrinkage (9.6%).

High temperature mechanical performance of a hot isostatically pressed silicon nitride

Energy Technology Data Exchange (ETDEWEB)

Wereszczak, A.A.; Ferber, M.K.; Jenkins, M.G.; Lin, C.K.J. [and others

1996-01-01

Silicon nitride ceramics are an attractive material of choice for designers and manufacturers of advanced gas turbine engine components for many reasons. These materials typically have potentially high temperatures of usefulness (up to 1400{degrees}C), are chemically inert, have a relatively low specific gravity (important for inertial effects), and are good thermal conductors (i.e., resistant to thermal shock). In order for manufacturers to take advantage of these inherent properties of silicon nitride, the high-temperature mechanical performance of the material must first be characterized. The mechanical response of silicon nitride to static, dynamic, and cyclic conditions at elevated temperatures, along with reliable and representative data, is critical information that gas turbine engine designers and manufacturers require for the confident insertion of silicon nitride components into gas turbine engines. This final report describes the high-temperature mechanical characterization and analyses that were conducted on a candidate structural silicon nitride ceramic. The high-temperature strength, static fatigue (creep rupture), and dynamic and cyclic fatigue performance were characterized. The efforts put forth were part of Work Breakdown Structure Subelement 3.2.1, {open_quotes}Rotor Data Base Generation.{close_quotes} PY6 is comparable to other hot isostatically pressed (HIPed) silicon nitrides currently being considered for advanced gas turbine engine applications.

Effect of Tooling Material on the Internal Surface Quality of Ti6Al4V Parts Fabricated by Hot Isostatic Pressing

Science.gov (United States)

Cai, Chao; Song, Bo; Wei, Qingsong; Yan, Wu; Xue, Pengju; Shi, Yusheng

2017-01-01

For the net-shape hot isostatic pressing (HIP) process, control of the internal surface roughness of as-HIPped parts remains a challenge for practical engineering. To reveal the evolution mechanism of the internal surface of the parts during the HIP process, the effect of different tooling materials (H13, T8, Cr12 steel, and graphite) as internal cores on the interfacial diffusion and surface roughness was systematically studied.

Microstructural and mechanical characteristics of W–2Ti and W–1TiC processed by hot isostatic pressing

Energy Technology Data Exchange (ETDEWEB)

Muñoz, A., E-mail: angel.munoz@uc3m.es [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad, 30, E28911 Leganés (Spain); Savoini, B. [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad, 30, E28911 Leganés (Spain); Tejado, E. [Departamento de Ciencia de Materiales, E.T.S. I. de Ingenieros de Caminos, Canales y Puertos, Universidad Politécnica de Madrid, E28040 Madrid (Spain); Centro Nacional de Investigaciones Metalúrgicas (C.S.I.C), Av. Gregorio del Amo, 8, E2840 Madrid (Spain); Monge, M.A. [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad, 30, E28911 Leganés (Spain); Pastor, J.Y. [Departamento de Ciencia de Materiales, E.T.S. I. de Ingenieros de Caminos, Canales y Puertos, Universidad Politécnica de Madrid, E28040 Madrid (Spain); Pareja, R. [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad, 30, E28911 Leganés (Spain)

2014-12-15

W–2Ti and W–1TiC alloys were produced by mechanical alloying and consolidation by hot isostatic pressing. The composition and microstructural characteristics of these alloys were studied by X-ray diffraction, energy dispersion spectroscopy and scanning electron microscopy. The mechanical behavior of the consolidated alloys was characterized by microhardness measurements and three point bending tests. The mechanical characteristics of the W–2Ti alloy appear to be related to solution hardening. In W–1TiC, the residual porosity should be responsible for the poor behavior observed in comparison with W–2Ti.

Microstructural and mechanical characteristics of W–2Ti and W–1TiC processed by hot isostatic pressing

International Nuclear Information System (INIS)

Muñoz, A.; Savoini, B.; Tejado, E.; Monge, M.A.; Pastor, J.Y.; Pareja, R.

2014-01-01

W–2Ti and W–1TiC alloys were produced by mechanical alloying and consolidation by hot isostatic pressing. The composition and microstructural characteristics of these alloys were studied by X-ray diffraction, energy dispersion spectroscopy and scanning electron microscopy. The mechanical behavior of the consolidated alloys was characterized by microhardness measurements and three point bending tests. The mechanical characteristics of the W–2Ti alloy appear to be related to solution hardening. In W–1TiC, the residual porosity should be responsible for the poor behavior observed in comparison with W–2Ti

Study on the process of sintering matrix metallic Fe-Cu-25%Nb and Fe-Cu-25%Co during hot pressing

International Nuclear Information System (INIS)

Batista, A.C.; Oliveira, H.C.P.; Souza, M.H.; Assis, P.S.

2016-01-01

The sintering process promotes densification and the evolution of the microstructure of the material, with consequent significant increase in hardness and mechanical strength. However, few studies show the influence of pressure and temperature during sintering by hot pressing. In this sense, this work aims to evaluate the microstructural changes and properties with the variation of pressure and temperature and the type suffered by sintering metal powders during sintering by hot pressing. For this, two samples were studied by changing the sintering parameters: 25% Fe-50% Cu-25% Nb and 25% Fe-50% Cu-25% Co. Samples were analyzed by SEM / EDS in order to check the morphology and the presence of pores, as well as the interaction between the metallic constituents of each sample by the EDS analysis in line. They also determined the relative density, porosity and Vickers hardness (HV5). At the end of the study it was concluded that niobium alloy composite element by sintering activated suffered together with the liquid phase sintering. For cobalt alloys were observed by liquid phase sintering. The increase in the severity of the sintering conditions (temperature and pressure) led to an improvement in physical and mechanical properties of the alloys, which indicates that these parameters are directly related to the mechanisms of diffusion in the sintering process, improving the properties and diffusivity between elements. (author)

Characterization and Formability of Titanium/Aluminum Laminate Composites Fabricated by Hot Pressing

Science.gov (United States)

Qin, Liang; Wang, Hui; Cui, Shengqiang; Wu, Qian; Fan, Minyu; Yang, Zonghui; Tao, Jie

2017-07-01

The Ti/Al laminate composites were prepared by hot pressing to investigate the forming performance due to the corresponding potential applications in both the aerospace and auto industry. The bonding interface morphology and element distributions were characterized by SEM and EDS. The phase constituent was detected by XRD. It was observed that these composites presented good bonding interfaces between Ti and Al layers, and no low-sized voids and intermetallic compounds formed at the interface. In addition, the formability of these laminate composites was studied by the uniaxial tension tests, the limit drawing ratio (LDR) and the forming limit curve (FLC) experiments, respectively. The results indicated that the flow stress increased along with the strain rate increment. A constitutive equation was developed for deformation behavioral description of these laminate composites. The LDR value was 1.8, and the most susceptible region to present cracks was located at the punch profile radius. The forming limit curve of the laminate composites was located between the curves of titanium and aluminum and intersected with the major strain line at approximately 0.31. The macroscopic cracks of the FLC sample demonstrated a saw-toothed crack feature.

Effect of Liquid Phase Content on Thermal Conductivity of Hot-Pressed Silicon Carbide Ceramics

International Nuclear Information System (INIS)

Lim, Kwang-Young; Jang, Hun; Lee, Seung-Jae; Kim, Young-Wook

2015-01-01

Silicon carbide (SiC) is a promising material for Particle-Based Accident Tolerant (PBAT) fuel, fission, and fusion power applications due to its superior physical and thermal properties such as low specific mass, low neutron cross section, excellent radiation stability, low coefficient of thermal expansion, and high thermal conductivity. Thermal conductivity of PBAT fuel is one of very important factors for plant safety and energy efficiency of nuclear reactors. In the present work, the effect of Y 2 O 3 -Sc 2 O 3 content on the microstructure and thermal properties of the hot pressed SiC ceramics have been investigated. Suppressing the β to α phase transformation of SiC ceramics is beneficial in increasing the thermal conductivity of liquid-phase sintered SiC ceramics. Developed SiC ceramics with Y 2 O 3 -Sc 2 O 3 additives are very useful for thermal conductivity on matrix material of the PBAT fuel

Effect of reduced cobalt contents on hot isostatically pressed powder metallurgy U-700 alloys

Science.gov (United States)

Harf, F. H.

1982-01-01

The effect of reducing the cobalt content of prealloyed powders of UDIMET 700 (U-700) alloys to 12.7, 8.6, 4.3, and 0% was examined. The powders were hot isostatically pressed into billets, which were given heat treatments appropriate for turbine disks, namely partial solutioning at temperatures below the gamma prime solvus and four step aging treatments. Chemical analyses, metallographic examinations, and X-ray diffraction measurements were performed on the materials. Minor effects on gamma prime content and on room temperature and 650 C tensile properties were observed. Creep rupture lives at 650 C reached a maximum at the 8.4% concentration, while at 760 C a maximum in life was reached at the 4.3% cobalt level. Minimum creep rates increased with decreasing cobalt content at both test temperatures. Extended exposures at 760 and 815 C resulted in decreased tensile strengths and rupture lives for all alloys. Evidence of sigma phase formation was also found.

Intergranular phase of the Si3 N4 hot pressed with Mg O/Y2 O3

International Nuclear Information System (INIS)

Costa, Celio A.; Todd, Judith A.

1997-01-01

Monolithic and composite Si 3 N 4 hot-pressed with 3% Mgo or 6% Y 2 O 3 were analyzed with X-ray diffraction and transmission electron microscopy. The results showed materials to be composed of β-Si 3 N 4 grains and an intergranular phase which was partially crystalline and partially amorphous. For the materials sintered with Mg O, the identification of the intergranular phase was not conclusive. For the materials sintered with Y 2 O 3 . It was observed that the amount of intergranular crystalline phase decreased as whiskers were added to the material and the intergranular crystalline part had a crystallographic structure similar to yttrium-silicon-oxide-nitride family. (author)

Verification of the effect of surface preparation on Hot Isostatic Pressing diffusion bonding joints of CLAM steel

Energy Technology Data Exchange (ETDEWEB)

Zhao, Yanyun [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Li, Chunjing, E-mail: chunjing.li@fds.org.cn [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Bo; Liu, Shaojun [Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Huang, Qunying [University of Science and Technology of China, Hefei, Anhui 230027 (China); Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

2014-12-15

Hot Isostatic Pressing (HIP) diffusion bonding with CLAM steel is the primary candidate fabrication technique for the first wall (FW) of DFLL-TBM. Surface state is one of the key factors for the joints quality. The effect of surface state prepared with grinder and miller on HIP diffusion bonding joints of CLAM steel was investigated. HIP diffusion bonding was performed at 140 MPa and 1373 K within 3 h. The mechanical properties of the joints were investigated with instrumented Charpy V-notch impact tests and the microstructures of the joints were analyzed with scanning electron microscopy (SEM). The results showed that the milled samples with fine surface roughness were more suitable for CLAM steel HIP diffusion bonding.

Fundamental Aspects of Zeolite Waste Form Production by Hot Isostatic Pressing

Energy Technology Data Exchange (ETDEWEB)

Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jordan, Jacob A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-02-01

The direct conversion of iodine-bearing sorbents into a stable waste form is a research topic of interest to the US Department of Energy. The removal of volatile radioactive 129I from the off-gas of a nuclear fuel reprocessing facility will be necessary in order to comply with the regulatory requirements that apply to facilities sited within the United States (Jubin et al., 2012a), and any iodine-containing media or solid sorbents generated by this process would contain ¹²⁹I and would be destined for eventual geological disposal. While recovery of iodine from some sorbents is possible, a method to directly convert iodineloaded sorbents to a durable waste form with little or no additional waste materials being formed and a potentially reduced volume would be beneficial. To this end, recent studies have investigated the conversion of iodine-loaded silver mordenite (I-AgZ) directly to a waste form by hot isostatic pressing (HIPing) (Bruffey and Jubin, 2015). Silver mordenite (AgZ), of the zeolite class of minerals, is under consideration for use in adsorbing iodine from nuclear reprocessing off-gas streams. Direct conversion of I-AgZ by HIPing may provide the following benefits: (1) a waste form of high density that is tolerant to high temperatures, (2) a waste form that is not significantly chemically hazardous, and (3) a robust conversion process that requires no pretreatment.

Microstructures and mechanical properties of Cu/Ti{sub 3}SiC{sub 2}/C/MWCNTs composites prepared by vacuum hot-pressing sintering

Energy Technology Data Exchange (ETDEWEB)

Xiaosong, Jiang, E-mail: xsjiang@yeah.net [School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Liu, Wanxia; Li, Jingrui [School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Shao, Zhenyi [Department of Mechanical Engineering, Chengdu Technological University, Chengdu, Sichuan 610031 (China); Zhu, Degui [School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)

2015-01-05

Highlights: • Cu/Ti{sub 3}SiC{sub 2}/C/MWCNTs composites were prepared using vacuum hot-pressing sintering. • Dispersions of MWCNTs were prepared using 10 μg/ml gallic acid aqueous solution. • MWCNTs content has no effect on generation of TiC and Cu{sub 9}Si to effect matrix’s performance. - Abstract: Cu/Ti{sub 3}SiC{sub 2}/C/MWCNTs composites were prepared by vacuum hot-pressing sintering. Microstructures and mechanical properties of Cu/Ti{sub 3}SiC{sub 2}/C/MWCNTs composites with different multi-walled carbon nanotubes contents have been systematically investigated. The microstructures of the composites were examined by optical microscopy, X-ray diffraction, back scattered electron imaging, scanning electron microscope and energy dispersive spectrometer. The mechanical properties were determined from Brinell hardness and tensile tests. The results demonstrated that there was an optimum value of MWCNTs content which has an impact on microstructures and mechanical properties of Cu/Ti{sub 3}SiC{sub 2}/C/MWCNTs composites. Based on MWCNTs content on properties and microstructure of Cu/Ti{sub 3}SiC{sub 2}/C/MWCNTs composites, effects of MWCNTs on improvement of the composites and strengthening mechanism have been analyzed.

Fabrication of dense yttrium oxyfluoride ceramics by hot pressing and their mechanical, thermal, and electrical properties

Science.gov (United States)

Tahara, Ryuki; Tsunoura, Toru; Yoshida, Katsumi; Yano, Toyohiko; Kishi, Yukio

2018-06-01

Excellent corrosion-resistant materials have been strongly required to reduce particle contamination during the plasma process in semiconductor production. Yttrium oxyfluoride can be a candidate as highly corrosion-resistant material. In this study, three types of dense yttrium oxyfluoride ceramics with different oxygen contents, namely, YOF, Y5O4F7 and Y5O4F7 + YF3, were fabricated by hot pressing, and their mechanical, thermal, and electrical properties were evaluated. Y5O4F7 ceramics showed an excellent thermal stability up to 800 °C, a low loss factor, and volume resistivity comparable to conventional plasma-resistant oxides, such as Y2O3. From these results, yttrium oxyfluoride ceramics are strongly suggested to be used as electrostatic chucks in semiconductor production.

M3FT-17OR0301070211 - Preparation of Hot Isostatically Pressed AgZ Waste Form Samples

Energy Technology Data Exchange (ETDEWEB)

Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jordan, Jacob A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-10-01

The production of radioactive iodine-bearing waste forms that exhibit long-term stability and are suitable for permanent geologic disposal has been the subject of substantial research interest. One potential method of iodine waste form production is hot isostatic pressing (HIP). Recent studies at Oak Ridge National Laboratory (ORNL) have investigated the conversion of iodine-loaded silver mordenite (I-AgZ) directly to a waste form by HIP. ORNL has performed HIP with a variety of sample compositions and pressing conditions. The base mineral has varied among AgZ (in pure and engineered forms), silver-exchanged faujasite, and silverexchanged zeolite A. Two iodine loading methods, occlusion and chemisorption, have been explored. Additionally, the effects of variations in temperature and pressure of the process have been examined, with temperature ranges of 525°C–1,100°C and pressure ranges of 100–300 MPa. All of these samples remain available to collaborators upon request. The sample preparation detailed in this document is an extension of that work. In addition to previously prepared samples, this report documents the preparation of additional samples to support stability testing. These samples include chemisorbed I-AgZ and pure AgI. Following sample preparation, each sample was processed by HIP by American Isostatic Presses Inc. and returned to ORNL for storage. ORNL will store the samples until they are requested by collaborators for durability testing. The sample set reported here will support waste form durability testing across the national laboratories and will provide insight into the effects of varied iodine content on iodine retention by the produced waste form and on potential improvements in waste form durability provided by the zeolite matrix.

Atom Probe Tomography of Phase and Grain Boundaries in Experimentally-Deformed and Hot-Pressed Wehrlite

Science.gov (United States)

Cukjati, J.; Parman, S. W.; Cooper, R. F.; Zhao, N.

2017-12-01

Atom probe tomography (APT) was used to characterize the chemistry of three grain boundaries: an olivine-olivine (ol-ol) and olivine-clinopyroxene (ol-cpx) boundary in fine-grained experimentally-deformed wehrlite and an ol-cpx boundary in a fine-grained, hot-pressed wehrlite. Grain boundaries were extracted and formed into APT tips using a focused ion beam (FIB). The tips were analyzed in a reflectron-equipped LEAP4000HR (Harvard University) at 1% or 0.5% detection rate, 5pJ laser energy and 100kHz pulse rate. Total ion counts are between 40 and 100 million per tip. Examination of grain and phase boundaries in wehrlite are of interest since slow-diffusing and olivine-incompatible cations present in cpx (e.g. Ca and Al) may control diffusion-accommodated grain boundary sliding and affect mantle rheology (Sundberg & Cooper, 2008). At steady state, ol-cpx aggregates are weaker than either ol or cpx end member, the results of which are not currently well-explained. We investigate grain boundary widths to understand the transport of olivine-incompatible elements. Widths of grain/phase boundary chemical segregation are between 3nm and 6nm for deformed ol-ol and ol-cpx samples; minimally-deformed (hot-pressed) samples having slightly wider chemical segregation widths. Chemical segregation widths were determined from profiles of Na, Al, P, Cl, K, Ca, or Ni, although not all listed elements can be used for all samples (e.g. Na, K segregation profiles can only be observed for ol-ol sample). These estimates are consistent with prior estimates of grain boundary segregation by atom probe tomography on ol-ol and opx-opx samples (Bachhav et al., 2015) and are less than ol-ol interface widths analyzed by STEM/EDX (Hiraga, Anderson, & Kohlstedt, 2007). STEM/EDX will be performed on deformed wehrlite to investigate chemical profile as a function of applied stress orientation and at length scales between those observable by APT and EPMA. Determination of phase boundary chemistry and

Fabrication of Al-based composites reinforced with in situ devitrified Al{sub 84}Ni{sub 8.4}Y{sub 4.8}La{sub 1.8}Co{sub 1} particles by hot pressing consolidation

Energy Technology Data Exchange (ETDEWEB)

Yang, Qing, E-mail: buaayq00@gmail.com; Zhang, Yitan; Zhang, Haiping; Zheng, Ruixiao; Xiao, Wenlong; Ma, Chaoli, E-mail: machaoli@buaa.edu.cn

2015-11-05

In this study, Al{sub 84}Ni{sub 8.4}Y{sub 4.8}La{sub 1.8}Co{sub 1} particles reinforced Al-based composites were prepared by hot pressing sintering and subsequent hot extrusion. The glassy powders were produced by gas atomization and then employed to mechanical milling. After hot pressing sintering, the nano-scale intermetallic compounds precipitated from metallic glass matrix due to higher temperature than super-cooled liquid region. The mechanical properties of 2024 alloy were improved by addition of glassy particles. The ultimate compressive stress increased from 482 MPa for 2024 alloy to 545 MPa, 627 MPa and 735 MPa for composites with 20 w.t.% 40 w.t.% and 60 w.t.% glassy powders addition, respectively, together with considerable fracture strain ranging between 2.9% and 13.6%. And the mechanical properties could be predicted by using the Rule of Mixture, which predicts the mechanical properties of the bulks from the volume weighed average of the constituent properties. - Highlights: • The composites are fabricate by hot pressing and extrusion. • The single phase of amorphous alloy is obtained by sieving. • The nano-scale compounds precipitates from glassy matrix. • The compressive strength reaches to the value of 735 MPa. • The strength can fit well with rule of mixture.

Inversion defects in MgAl2O4 elaborated by pressureless sintering, pressureless sintering plus hot isostatic pressing, and spark plasma sintering

International Nuclear Information System (INIS)

Mussi, A.; Granger, G. Bernard; Addad, A.; Benameur, N.; Beclin, F.; Bataille, A.

2009-01-01

The distribution of inversion defects of Al was investigated in dense magnesium-aluminate spinel elaborated by pressureless sintering, pressureless sintering plus hot isostatic pressing, and spark plasma sintering. This study was conducted by energy electron loss spectroscopy analyses and more particularly by energy loss near edge structure investigations of the Al-L 2,3 edge. Several aspects are discussed with the purpose of understanding why charged defects dispersal reveals a special configuration.

Effect of gas release in hot molding on flexural strength of composite friction brake

Science.gov (United States)

Rusdja, Andy Permana; Surojo, Eko; Muhayat, Nurul; Raharjo, Wijang Wisnu

2018-02-01

Composite friction brake is a vital part of braking system which serves to reduce the speed of vehicle. To fulfill the requirement of brake performance, composite friction brake must have friction and mechanical characteristic as required. The characteristics of composite friction brake are affected by brake material formulation and manufacturing parameter. In the beginning of hot molding, intermittent hot pressing was carried out to release the gases that consist of ammonia gas and water vapor. In composite friction brake, phenolic resin containing hexamethylenetetramine (HMTA) is often used as a binder. During hot molding, the reaction of phenolic resin and HMTA forms ammonia gas. Hot molding also generates water vapor because raw materials absorb moisture from environment when they are placed in storage. The gas release in hot molding is supposed affecting mechanical properties because it avoid entrapped gas in composite, so that this research investigated effect of gas release on flexural strength. Manufacturing of composite specimen was carried out as follow: mixing of raw materials, cold molding, and hot molding. In this research, duration of intermittent hot pressing and number of gas release were varied. The flexural strength of specimen was measured using three point bending test. The results showed that flexural strength specimens that were manufactured without gas release, using 4 times gas release with intermittent hot pressing for 5 and 10 seconds were not remarkably different. Conversely, hot molding using 4 times gas release with intermittent hot pressing for 15 seconds decreased flexural strength of composite. Hot molding using 2, 4, and 8 times gas release with intermittent hot pressing for 10 seconds also had no effect on increasing flexural strength. Increasing of flexural strength of composite was obtained only by using 6 times gas release with intermittent hot pressing for 10 seconds.

Age hardening in rapidly solidified and hot isostatically pressed beryllium-aluminum-silver alloys

International Nuclear Information System (INIS)

Carter, D.H.; McGeorge, A.C.; Jacobson, L.A.; Stanek, P.W.

1995-01-01

Three different alloys of beryllium, aluminum and silver were processed to powder by centrifugal atomization in a helium atmosphere. Alloy compositions were, by weight, 50% Be, 47.5% Al, 2.5% Ag, 50% Be, 47% Al, 3% Ag, and 50% Be, 46% Al, 4% Ag. Due to the low solubility of both aluminum and silver in beryllium, the silver was concentrated in the aluminum phase, which appeared to separate from the beryllium in the liquid phase. A fine, continuous composite beryllium-aluminum microstructure was formed, which did not significantly change after hot isostatically pressing at 550 C for one hour at 30,000 psi argon pressure. Samples of HIP material were solution treated at 550 C for one hour, followed by a water quench. Aging temperatures were 150, 175, 200 and 225 C for times ranging from one half hour to 65 hours. Hardness measurements were made using a diamond pyramid indenter with a load of 1 kg. Results indicate that peak hardness was reached in 36--40 hours at 175 C and 12--16 hours at 200 C aging temperature, relatively independent of alloy composition

Hot Isostatic Pressing of Engineered Forms of I-AgZ

Energy Technology Data Exchange (ETDEWEB)

Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Watkins, Thomas R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jordan, Jacob A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Parks, Mackenzie L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-11-01

Hot isostatic pressing (HIP) is being considered for direct conversion of ¹²⁹I-bearing materials to a radiological waste form. The removal of volatile radioactive ¹²⁹I from the off-gas of a nuclear fuel reprocessing facility will be necessary to comply with regulatory requirements regarding reprocessing facilities sited within the United States, and any iodine-containing media or solid sorbents generated by offgas abatement will require disposal. Zeolite minerals such as silver-exchanged mordenite (AgZ) have been studied as potential iodine sorbents and will contain ¹²⁹I as chemisorbed AgI. Oak Ridge National Laboratory (ORNL) has conducted several recent studies on the HIP of both iodine-loaded AgZ (I-AgZ) and other iodine-bearing zeolite minerals. The goal of these research efforts is to achieve a stable, highly leach resistant material that is reduced in volume as compared to bulk iodine-loaded I-AgZ. Through the use of HIP, it may be possible to achieve this with the addition of little or no additional materials (waste formers). Other goals for the process include that the waste form will be tolerant to high temperatures and pressures, not chemically hazardous, and that the process will result in minimal secondary waste generation. This document describes the preparation of 27 samples that are distinct from previous efforts in that they are prepared exclusively with an engineered form of AgZ that is manufactured using a binder. Iodine was incorporated solely by chemisorption. This base material is expected to be more representative of an operational system than were samples prepared previously with pure minerals.

Mechanochemical Effects on the Synthesis of Copper Orthophosphate and cyclo-Tetraphosphate Bulks by the Hydrothermal Hot Pressing Method

Directory of Open Access Journals (Sweden)

Isao Tanaka

2009-01-01

Full Text Available Copper orthophosphate, Cu3(PO42, and cyclo-tetraphosphates, Cu2P4O12, were synthesized using phosphoric acid and basic copper carbonate, and then treated with a planetary mill for up to 360 minutes. The un-milled and milled samples were characterized by X-ray diffraction (XRD and Fourier transform infrared (FT-IR spectroscopy. SEM images, particle size distribution, specific surface area, UV-Vis reflectance spectra were also used to evaluate the materials. The un-milled and milled materials were used to fabricate copper phosphate bulks by a hydrothermal hot pressing method. The influence of powder condition on the sintering behavior of the copper phosphates was studied.

SGEM Hot Off the Press: ultrasound during critical care simulation: a randomized crossover study.

Science.gov (United States)

McKenna, Paul; Thoma, Brent; Milne, Ken; Bond, Chris

2017-01-01

As part of the Canadian Journal of Emergency Medicine's (CJEM) developing social media strategy, 1 we are collaborating with the Skeptics' Guide to Emergency Medicine (SGEM) to summarize and critically appraise the current emergency medicine (EM) literature using evidence-based medicine principles. In the "Hot Off the Press" series, we select original research manuscripts published in CJEM to be featured on the SGEM website/podcast 2 and discussed by the study authors and the online EM community. A similar collaboration is underway between the SGEM and Academic Emergency Medicine. What follows is a summary of the selected article the immediate post-publication synthesis from the SGEM podcast, commentary by the first author, and the subsequent discussion from the SGEM blog and other social media. Through this series, we hope to enhance the value, accessibility, and application of important, clinically relevant EM research. In this, the third SGEM HOP hosted collaboratively with CJEM, we discuss Olszynski et al.'s randomized crossover study evaluating the use of ultrasound simulator devices during critical care simulation. 3.

Cyclic fatigue resistance of yttria-stabilized tetragonal zirconia polycrystals with hot isostatic press processing.

Science.gov (United States)

Koyama, Taku; Sato, Toru; Yoshinari, Masao

2012-01-01

This study investigated the influence of surface roughness and cyclic loading on fatigue resistance in Y-TZP subjected to hot isostatic pressing (HIP). Fifty Y-TZP cylinders 3.0 mm in diameter were divided into Group A (polished by centerless method; TZP-CP) or Group B (blasted and acid-etched: TZP-SB150E). Twenty five cp-titanium cylinders (Ti-SB150E) were used as a control. Static and cyclic tests were carried out according to ISO 14801. The cyclic fatigue test was performed in distilled water at 37°C. Surface morphology and roughness as well as crystal phase on the surfaces were also evaluated. Fracture force under the static test was 1,765N (TZP-CP), 1,220N (TZP-SB150E), and 850 N (yield force, Ti-SB150E). Fracture values under the cyclic test decreased to approximately 70% of those under the static tests. These results indicate that HIPed Y-TZP with a 3.0-mm diameter has sufficient durability for application to dental implants.

The substitution of nickel for cobalt in hot isostatically pressed powder metallurgy UDIMET 700 alloys

Science.gov (United States)

Harf, F. H.

1985-01-01

Nickel was substituted in various proportions for cobalt in a series of five hot-isostatically-pressed powder metallurgy alloys based on the UDIMET 700 composition. These alloys were given 5-step heat treatments appropriate for use in turbine engine disks. The resultant microstructures displayed three distinct sizes of gamma-prime particles in a gamma matrix. The higher cobalt-content alloys contained larger amounts of the finest gamma-prime particles, and had the lowest gamma-gamma-prime lattice mismatch. While all alloys had approximately the same tensile properties at 25 and 650 gamma C, the rupture lives at 650 and 760 C peaked in the alloys with cobalt contents between 12.7 and 4.3 pct. Minimum creep rates increased as cobalt contents were lowered, suggesting their correlation with the gamma-prime particle size distribution and the gamma-gamma-prime mismatch. It was also found that, on overaging at temperatures higher than suitable for turbine disk use, the high cobalt-content alloys were prone to sigma phase formation.

Comparative evaluation of electrical conductivity of hydroxyapatite ceramics densified through ramp and hold, spark plasma and post sinter Hot Isostatic Pressing routes

Energy Technology Data Exchange (ETDEWEB)

Buchi Suresh, M., E-mail: suresh@arci.res.in; Biswas, P.; Mahender, V.; Johnson, Roy, E-mail: royjohnson@arci.res.in

2017-01-01

Hydroxyapatite ceramics synthesized through sonochemical route were processed and densified through ramp & hold (R&H) and Spark Plasma Sintering (SPS) routes. The effect of processing route on the relative density and electrical conductivity were studied. Further, the samples were Hot Isostatically Pressed (HIP) under argon pressure at elevated temperature to further densify the sample. All these samples processed under different conditions were characterized by X-ray diffraction, Scanning Electron Microscopy and AC Conductivity. The samples have exhibited hydroxyapatite phase; however, microstructures exhibited distinctly different grain morphologies and grain sizes. AC impedance spectroscopic measurement was carried out on hydroxyapatite samples processed through different routes and the corresponding spectra were analyzed by the analogy to equivalent circuit involving resistors and capacitors. SPS sintered sample after HIPing has exhibited the highest conductivity. This can be attributed to the higher density in combination with finer grain sizes. Activation energy based on Arrhenius equation is calculated and the prominent conduction mechanism is proposed. - Highlights: • Hot Isostatic Pressing (HIP) of SPS and R&H processed samples has resulted into densities near to theoretical densities • No change in the crystal structure is observed in SPS and R&H samples before and after HIP treatment • SPS processed and HIP treated samples resulted into higher conductivities with smaller grain sizes and grain boundary area.

Thermoelectric properties of Bi2Te3-Bi2Se3 solid solutions prepared by attrition milling and hot pressing

International Nuclear Information System (INIS)

Lee, Go-Eun; Kim, Il-Ho; Choi, Soon-Mok; Lim, Young-Soo; Seo, Won-Seon; Park, Jae-Soung; Yang, Seung-Ho

2014-01-01

Bi 2 Te 3-y Se y (y = 0.15 - 0.6) solid solutions were prepared by attrition milling and hot pressing. The lattice constants decreased with increasing Se content, indicating that the Se atoms were successfully substituted into the Te sites. All specimens exhibited n-type conduction, and their electrical resistivities increased slightly with increasing temperature. With increasing Se content, the Seebeck coefficients increased while the thermal conductivity decreased due to the increase in phonon scattering. The maximum figure of merit obtained was 0.63 at 440 K for the undoped Bi 2 Te 2.4 Se 0.6 solid solution.

Hot working alkali halides for laser window applications

International Nuclear Information System (INIS)

Koepke, B.G.; Anderson, R.H.; Stokes, R.J.

1975-01-01

The techniques used to hot work alkali halide crystals into laser window blanks are reviewed. From the point of view of high power laser window applications one of the materials with a high figure of merit is KCl. Thus the materials examined are KCl and alloys of KCl-KBr containing 5 mole percent KBr. The fabrication techniques include conventional and constrained press forging, isostatic press forging and hot rolling. Optical properties are paramount to the ultimate usefulness of these materials. Results on the optical properties of the hot worked material are included together with mechanical properties and microstructural data

Bibliography on Hot Isostatic Pressing (HIP) Technology

Science.gov (United States)

1992-11-01

Nimonic API, Rene’ 77 2. MA753, IN-853 7 3. C-103,WC-103 4. Alloy 454, PWA 1480 5. Mar- M250 , Maraging (250) 6. Rene 150, PA 101 (low C) 7. Inconel 718...Pressure Welding Parameters Bryant. W. A. Weld J 54 (12), 433-S-435-S, 1975 ( AD-DI02 316 Key Words: AISI 4340. MAR- M250 . AISI 1020, 9Ni-4Co steel. Inconel...creep rupture. hot corrosion, oxidation, grain size, thermomechanical treatment MAR- M250 1. Microstructures and Mechanical Properties of HIP

A trapped field of >3 T in bulk MgB2 fabricated by uniaxial hot pressing

International Nuclear Information System (INIS)

Durrell, J H; Dennis, A; Shi, Y; Xu, Z; Campbell, A M; Babu, N Hari; Cardwell, D A; Dancer, C E J; Todd, R I; Grovenor, C R M

2012-01-01

A trapped field of over 3 T has been measured at 17.5 K in a magnetized stack of two disc-shaped bulk MgB 2 superconductors of diameter 25 mm and thickness 5.4 mm. The bulk MgB 2 samples were fabricated by uniaxial hot pressing, which is a readily scalable, industrial technique, to 91% of their maximum theoretical density. The macroscopic critical current density derived from the trapped field data using the Biot–Savart law is consistent with the measured local critical current density. From this we conclude that critical current density, and therefore trapped field performance, is limited by the flux pinning available in MgB 2 , rather than by lack of connectivity. This suggests strongly that both increasing sample size and enhancing pinning through doping will allow further increases in trapped field performance of bulk MgB 2 . (rapid communication)

Tensile and fracture characteristics of oxide dispersion strengthened Fe–12Cr produced by hot isostatic pressing

Energy Technology Data Exchange (ETDEWEB)

Castro, Vanessa de, E-mail: vanessa.decastro@uc3m.es [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid (Spain); Garces-Usan, Jose Maria; Leguey, Teresa; Pareja, Ramiro [Departamento de Física, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid (Spain)

2013-11-15

The mechanical characteristics of a model oxide dispersion strengthened (ODS) alloy with nominal composition Fe–12 wt%Cr–0.4 wt%Y{sub 2}O{sub 3} were investigated by means of microhardness measurements, tensile tests up to fracture in the temperature range of 298–973 K, and fracture surface analyses. A non-ODS Fe–12 wt%Cr alloy was also studied to assess the real capacity of the oxide dispersion for strengthening the alloy. The materials were produced by mechanical alloying followed by hot isostatic pressing consolidation and heat treatment at 1023 K. The strengthening effect of the oxide nanodispersion was effective at all temperatures studied, although the tensile strength converges towards the one obtained for the reference alloy at higher temperatures. Moreover, the ODS alloys failed prematurely at T < 673 K due to the presence of Y-rich inclusions, as seen in the fracture surface of these alloys.

Tensile and fracture characteristics of oxide dispersion strengthened Fe–12Cr produced by hot isostatic pressing

International Nuclear Information System (INIS)

Castro, Vanessa de; Garces-Usan, Jose Maria; Leguey, Teresa; Pareja, Ramiro

2013-01-01

The mechanical characteristics of a model oxide dispersion strengthened (ODS) alloy with nominal composition Fe–12 wt%Cr–0.4 wt%Y 2 O 3 were investigated by means of microhardness measurements, tensile tests up to fracture in the temperature range of 298–973 K, and fracture surface analyses. A non-ODS Fe–12 wt%Cr alloy was also studied to assess the real capacity of the oxide dispersion for strengthening the alloy. The materials were produced by mechanical alloying followed by hot isostatic pressing consolidation and heat treatment at 1023 K. The strengthening effect of the oxide nanodispersion was effective at all temperatures studied, although the tensile strength converges towards the one obtained for the reference alloy at higher temperatures. Moreover, the ODS alloys failed prematurely at T < 673 K due to the presence of Y-rich inclusions, as seen in the fracture surface of these alloys

First wall and shield components manufacturing by hot isostatic pressing

International Nuclear Information System (INIS)

Lind, Anders; Tegman, R.

1994-01-01

At a meeting in Garching in June 1994 Hot Isostatic Pressing (HIP) was presented as a possible route to manufacture ITER first wall and shield components. The main advantages of the HIP concept include excellent and uniform mechanical properties of the produced materials and joints, high reliability and robustness of the HIP process, double containment of coolant, good flexibility concerning general design as well as size and location for inner cooling tubes, low cost and short delivery times, and a good near net shape capability for components in size up to 15 tons. To assess the applicability of HIP for the manufacturing of ITER first wall and shield components, it was agreed * to choose possible production parameters based in the present know-how, * to produce a compound mock-up in one shot from available solid steel/powder copper/steel tubes to demonstrate the joinability of the materials, * to examine the produced mock-up/materials by multi array ultrasonic testing, limited mechanical testing, metallography, scanning electron microscopy and energy dispersive spectroscopy, and * to compile data on Type 316L steels produced by HIP. Preliminary results and the mock-up were presented at a meeting in Garching in mid July 1994. This study clearly shows the excellent joinability of a copper alloy (Cu-0.5%Zr) and stainless steels (Type 304, 316 L) by HIP at temperatures close to the melting temperature of copper, with only limited influence on the microstructures, which makes it possible to HIP the first wall and shield structure in one step. Excellent mechanical properties of the compound are obtained with the copper alloy and not the joint being the weakest part. 7 refs, 21 figs, 1 tab

Effects of internal gas pressure and microstructure on the mechanisms of hot-pressing and swelling in ceramics. Progress report, June 1, 1975--March 31, 1976

International Nuclear Information System (INIS)

Solomon, A.A.

1976-02-01

Pressurization system components for studying the hot-pressing and swelling behavior of CoO were built. A vacuum furnace was modified so that dimensional changes can be continuously monitored during sintering under high vacuum. Chracterization of the CoO starting powders was initiated. A technique was developed to form geometrically uniform pellet compacts of high green density using low pressure punch and die pressing followed by high pressure isostatic compaction to obtain uniform green density. Preliminary sintering experiments were carried out at 1 atm in air, inert gas, and under vacuum with specimen deflection continuously monitored. Resulting microstructures were characterized using mercury porosimetry and quantitative optical microscopy. Drastic differences in sintering rates in vacuum and air were observed

Investigation of hot- iso-static press process for tungsten target samples

International Nuclear Information System (INIS)

Xu Yongli; Zhang Jinquan; Li Huaqing

2006-01-01

Zr and stainless steel (S.S.) were selected respectively as the cladding materials of W target. The e-beam weld was used to prepare the W-Zr and W-S.S. small samples for hot iso-static press (HIP) process. The technology parameters of HIP were investigated at 1200, 1300, 1400 degree C and 180 MPa, respectively. The micro-morphology of the interface, diffusion depths and composition as well as their micro-hardness were observed and determined. The bonding of W-Zr and W-S.S. is very well under the testing conditions. There is no any pore or micro-crack in the interface, and there is no grain growth of W below 1400 degree C either. The diffusion of Zr to W at the interface of W-Zr is preferred during HIP process, and the diffusion depths under testing conditions are 6-13 μm. The diffusion of W and Fe is considerable at the interface of W-S.S. Its depth is about 13 μm, and the diffusion of Cr and Ni is mall. The hardness at the interface of W-Zr and W-S.S. shows that a diffusion layer is present for both interface. A part of stainless steel cladding was melted after HIP contained the oxygen absorber Zr at 1300 degree C and 180 MPa. Therefore, 1200 degree C and 180 MPa is suitable for W-S.S. without Zr, but 1300 or 1400 degree C and 180 MPa is better for W-Zr. (authors)

Modelling of powder die compaction for press cycle optimization

Directory of Open Access Journals (Sweden)

Bayle Jean-Philippe

2016-01-01

Full Text Available A new electromechanical press for fuel pellet manufacturing was built last year in partnership between CEA-Marcoule and ChampalleAlcen. This press was developed to shape pellets in a hot cell via remote handling. It has been qualified to show its robustness and to optimize the compaction cycle, thus obtaining a better sintered pellet profile and limiting damage. We will show you how 400 annular pellets have been produced with good geometry's parameters, based on press settings management. These results are according to a good phenomenological pressing knowledge with Finite Element Modeling calculation. Therefore, during die pressing, a modification in the punch displacement sequence induces fluctuation in the axial distribution of frictional forces. The green pellet stress and density gradients are based on these frictional forces between powder and tool, and between grains in the powder, influencing the shape of the pellet after sintering. The pellet shape and diameter tolerances must be minimized to avoid the need for grinding operations. To find the best parameters for the press settings, which enable optimization, FEM calculations were used and different compaction models compared to give the best calculation/physical trial comparisons. These simulations were then used to predict the impact of different parameters when there is a change in the type of powder and the pellet size, or when the behavior of the press changes during the compaction time. In 2016, it is planned to set up the press in a glove box for UO2 manufacturing qualification based on our simulation methodology, before actual hot cell trials in the future.

New concept bioceramics composed of octacalcium phosphate (OCP) and dicarboxylic acid-intercalated OCP via hydrothermal hot-pressing

Energy Technology Data Exchange (ETDEWEB)

Ishihara, Shiho [Graduate School of Engineering, Osaka Prefecture University (Japan); Matsumoto, Takuya [Graduate School of Dentistry, Osaka University (Japan); Onoki, Takamasa, E-mail: onoki@mtr.osakafu-u.ac.jp [Graduate School of Engineering, Osaka Prefecture University (Japan); Sohmura, Taiji [Graduate School of Dentistry, Osaka University (Japan); Nakahira, Atsushi [Graduate School of Engineering, Osaka Prefecture University (Japan)

2009-08-01

Octacalcium phosphate (OCP) and adipic acid-intercalated complexed OCP (Adi-OCP) were synthesized. Moreover, we made ceramic bodies out of them through a hydrothermal hot-pressing (HHP) method. Characteristic features of both the powder and ceramics were investigated by the X-ray diffraction method (XRD). Surface morphology of the ceramics was observed by scanning electron microscopy (SEM). Density, compressive strength and pore size distribution of the ceramics were measured. Crystalline structure of the newly developed OCP ceramics had no phase transformation from the starting materials. Moreover, the newly developed OCP ceramics had good mechanical properties only through the HHP treatment with a temperature as low as 110 deg. C. In order to evaluate bioactivity, the ceramics were immersed in simulating body fluid (SBF). It was predicted that OCP and Adi-OCP had better bioactivity than that of conventional HAp ceramics.

Forming and control of pores by capsule-free hot isostatic pressing in NiTi shape memory alloys

International Nuclear Information System (INIS)

Yuan, B; Zhu, M; Gao, Y; Li, X; Chung, C Y

2008-01-01

In this study, the pore evolution process of porous NiTi shape memory alloys (SMAs) fabricated by capsule-free hot isostatic pressing (CF-HIP) was investigated by adopting different fabricating parameters. It is shown that porous NiTi SMAs with homogeneous pore distribution and nearly spherical pore shape can be prepared by CF-HIP under suitable conditions. In addition, two novel pore structures were produced, one with a sandwich-like structure, and another with controlled gradient of porosity along the radial direction, with pore size increasing from the outside towards the center of the specimen. The former was obtained by balancing the pressure in the HIP chamber and the gas pressure resulting from the gas expansion in the green sample. The latter resulted from the formation of air bubbles in the liquid phase during the sintering

Effects of Temperature and Pressure of Hot Isostatic Pressing on the Grain Structure of Powder Metallurgy Superalloy.

Science.gov (United States)

Tan, Liming; He, Guoai; Liu, Feng; Li, Yunping; Jiang, Liang

2018-02-24

The microstructure with homogeneously distributed grains and less prior particle boundary (PPB) precipitates is always desired for powder metallurgy superalloys after hot isostatic pressing (HIPping). In this work, we studied the effects of HIPping parameters, temperature and pressure on the grain structure in PM superalloy FGH96, by means of scanning electron microscope (SEM), electron backscatter diffraction (EBSD), transmission electron microscope (TEM) and Time-of-flight secondary ion spectrometry (ToF-SIMS). It was found that temperature and pressure played different roles in controlling PPB precipitation and grain structure during HIPping, the tendency of grain coarsening under high temperature could be inhibited by increasing HIPping pressure which facilitates the recrystallization. In general, relatively high temperature and pressure of HIPping were preferred to obtain an as-HIPped superalloy FGH96 with diminished PPB precipitation and homogeneously refined grains.

New concept bioceramics composed of octacalcium phosphate (OCP) and dicarboxylic acid-intercalated OCP via hydrothermal hot-pressing

International Nuclear Information System (INIS)

Ishihara, Shiho; Matsumoto, Takuya; Onoki, Takamasa; Sohmura, Taiji; Nakahira, Atsushi

2009-01-01

Octacalcium phosphate (OCP) and adipic acid-intercalated complexed OCP (Adi-OCP) were synthesized. Moreover, we made ceramic bodies out of them through a hydrothermal hot-pressing (HHP) method. Characteristic features of both the powder and ceramics were investigated by the X-ray diffraction method (XRD). Surface morphology of the ceramics was observed by scanning electron microscopy (SEM). Density, compressive strength and pore size distribution of the ceramics were measured. Crystalline structure of the newly developed OCP ceramics had no phase transformation from the starting materials. Moreover, the newly developed OCP ceramics had good mechanical properties only through the HHP treatment with a temperature as low as 110 deg. C. In order to evaluate bioactivity, the ceramics were immersed in simulating body fluid (SBF). It was predicted that OCP and Adi-OCP had better bioactivity than that of conventional HAp ceramics.

Fabrication of SiCp/Al Alloy Composites by In-situ Vacuum Hot Press Process

Energy Technology Data Exchange (ETDEWEB)

Choi, S. W.; Hong, S. K.; Kim, Y. M.; Kang, C. S. [Chonnam National University, Kwangju (Korea); Chang, S. Y. [Hanyang University, Seoul (Korea)

2001-07-01

SiCp/pure Al and SiCp/2024Al MMCs were fabricated by in-situ VHP process designed specially just in this study which is composed of the vacuum hot press at range from R.T. to 500 deg.C and the continuous extrusion without canning process at 520 deg.C. It was investigated the effect of SiC particle size, volume fraction and extrusion ratio on the tensile properties and micro structure in all composites. In case of the 10:1 extrusion ratio, but SiCp/pure Al and SiCp/2024Al composites were shown a sound appearance and a good micro structure without crack of SiCp as well as uniform distribution of SiCp. However, in case of the 16:1 extrusion ratio, the number of cracked SiC particles more than increased in a higher volume fraction composite and 2024Al matrix composite compared with pure Al matrix one. The tensile strength of the composites reinforced smaller SiCp was higher than that of the bigger SiCp reinforced in same volume fraction and extrusion ratio. (author) 14 refs., 14 figs.

Pre-brazed casting and hot radial pressing: A reliable process for the manufacturing of CFC and W monoblock mock-ups

International Nuclear Information System (INIS)

Visca, Eliseo; Libera, S.; Mancini, A.; Mazzone, G.; Pizzuto, A.; Testani, C.

2007-01-01

ENEA is involved in the European International Thermonuclear Experimental Reactor (ITER) R and D activities and, in particular, for the manufacturing of high heat flux plasma-facing components (HHFC), such as the divertor targets, the baffles and the limiters. During last years, ENEA has manufactured actively cooled mock-ups by using different technologies, namely brazing, diffusion bonding and hot isostatic pressing (HIPping). A new manufacturing process has been set up and tested. It was successfully applied for the manufacturing of W armoured monoblock mock-ups. This technique is the HRP (hot radial pressing) based on performing a radial diffusion bonding between the cooling tube and the armour tile by pressurizing only internal tube and by keeping the joining zone in vacuum at the required bonding temperature. The heating is obtained by a standard air furnace. The HRP technique is now used for the manufacturing of CFC armoured monoblock components. For this purpose, some issues have to be faced, like the low CFC tensile strength, the pure copper interlayer between the heat sink and the armour necessary to mitigate the stress at the joint interface, and the low wettability of the pure copper on the CFC matrix. This paper reports the research path followed to manufacture a medium scale vertical target CFC and W armoured mock-up by HRP. A casting of a soft copper interlayer between the tube and the tile was obtained by a new technique: the pre-brazed casting (PBC, ENEA patent). Some preliminary mock-ups with three NB31 CFC tiles were successfully manufactured and tested to thermal fatigue using electron beam facilities. They all reached at least 1000 cycles at 20 MW/m 2 without suffering any damage. The manufactured medium scale vertical target mock-up is now under testing at the FE2000 (France) facility. These activities were performed in the frame of ITER-EFDA contracts

The effect of pre-treatment parameters on the quality of glass-ceramic wasteforms for plutonium immobilisation, consolidated by hot isostatic pressing

Energy Technology Data Exchange (ETDEWEB)

Thornber, Stephanie M.; Heath, Paul G. [Immobilisation Science Laboratory, Department of Materials Science & Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD (United Kingdom); Da Costa, Gabriel P. [Immobilisation Science Laboratory, Department of Materials Science & Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD (United Kingdom); Department of Chemical Engineering & Petroleum Engineering, Universidade Federal Fluminense, Rua Passo da Patria 156, CEP 24210-240, Niteroi, RJ (Brazil); Stennett, Martin C. [Immobilisation Science Laboratory, Department of Materials Science & Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD (United Kingdom); Hyatt, Neil C., E-mail: n.c.hyatt@sheffield.ac.uk [Immobilisation Science Laboratory, Department of Materials Science & Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD (United Kingdom)

2017-03-15

Glass-ceramics with high glass fractions (70 wt%) were fabricated in stainless steel canisters by hot isostatic pressing (HIP), at laboratory scale. High (600 °C) and low (300 °C) temperature pre-treatments were investigated to reduce the canister evacuation time and to understand the effect on the phase assemblage and microstructure of the hot isostatically pressed product. Characterisation of the HIPed materials was performed using scanning electron microscopy (SEM), coupled with energy dispersive X-ray analysis (EDX) and powder X-ray diffraction (XRD). This analysis showed the microstructure and phase assemblage was independent of the variation in pre-treatment parameters. It was demonstrated that a high temperature pre-treatment of batch reagents, prior to the HIP cycle, is beneficial when using oxide precursors, in order to remove volatiles and achieve high quality dense materials. Sample throughput can be increased significantly by utilising a high temperature ex-situ calcination prior to the HIP cycle. Investigation of glass-ceramic wasteform processing utilising a glass frit precursor, produced a phase assemblage and microstructure comparable to that obtained using oxide precursors. The use of a glass frit precursor should allow optimised throughput of waste packages in a production facility, avoiding the need for a calcination pre-treatment required to remove volatiles from oxide precursors. - Highlights: • Optimisation of pre-treatment parameters for HIP glass-ceramics was investigated. • Entrained porosity was minimised by ex-situ bake-out of oxide precursors at 600 °C. • Phase assemblage and microstructure proved independent of bake-out parameters. • Use of glass-frit precursor further improved process s throughput and simplification.

Tensile ductility of an AlCoCrFeNi multi-phase high-entropy alloy through hot isostatic pressing (HIP) and homogenization

Energy Technology Data Exchange (ETDEWEB)

Tang, Zhi, E-mail: Zhi.Tang@alcoa.com [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States); Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24061 (United States); Senkov, Oleg N. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH 45433 (United States); Parish, Chad M. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zhang, Chuan; Zhang, Fan [CompuTherm LLC, 437 S. Yellowstone Dr., Suite 217, Madison, WI 53719 (United States); Santodonato, Louis J. [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States); Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Wang, Gongyao [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States); Zhao, Guangfeng; Yang, Fuqian [Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States); Liaw, Peter K., E-mail: pliaw@utk.edu [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States)

2015-10-28

The microstructure and phase composition of an AlCoCrFeNi high-entropy alloy (HEA) were studied in as-cast (AlCoCrFeNi-AC, AC represents as-cast) and homogenized (AlCoCrFeNi-HP, HP signifies hot isostatic pressed and homogenized) conditions. The AlCoCrFeNi-AC ally has a dendritric structure in the consisting primarily of a nano-lamellar mixture of A2 (disordered body-centered-cubic (BCC)) and B2 (ordered BCC) phases, formed by an eutectic reaction. The homogenization heat treatment, consisting of hot isostatic pressed for 1 h at 1100 °C, 207 MPa and annealing at 1150 °C for 50 h, resulted in an increase in the volume fraction of the A1 phase and formation of a Sigma (σ) phase. Tensile properties in as-cast and homogenized conditions are reported at 700 °C. The ultimate tensile strength was virtually unaffected by heat treatment, and was 396±4 MPa at 700 °C. However, homogenization produced a noticeable increase in ductility. The AlCoCrFeNi-AC alloy showed a tensile elongation of only 1.0%, while after the heat-treatment, the elongation of AlCoCrFeNi-HP was 11.7%. Thermodynamic modeling of non-equilibrium and equilibrium phase diagrams for the AlCoCrFeNi HEA gave good agreement with the experimental observations of the phase contents in the AlCoCrFeNi-AC and AlCoCrFeNi-HP. The reasons for the improvement of ductility after the heat treatment and the crack initiation subjected to tensile loading were discussed.

The effect of pre-treatment parameters on the quality of glass-ceramic wasteforms for plutonium immobilisation, consolidated by hot isostatic pressing

International Nuclear Information System (INIS)

Thornber, Stephanie M.; Heath, Paul G.; Da Costa, Gabriel P.; Stennett, Martin C.; Hyatt, Neil C.

2017-01-01

Glass-ceramics with high glass fractions (70 wt%) were fabricated in stainless steel canisters by hot isostatic pressing (HIP), at laboratory scale. High (600 °C) and low (300 °C) temperature pre-treatments were investigated to reduce the canister evacuation time and to understand the effect on the phase assemblage and microstructure of the hot isostatically pressed product. Characterisation of the HIPed materials was performed using scanning electron microscopy (SEM), coupled with energy dispersive X-ray analysis (EDX) and powder X-ray diffraction (XRD). This analysis showed the microstructure and phase assemblage was independent of the variation in pre-treatment parameters. It was demonstrated that a high temperature pre-treatment of batch reagents, prior to the HIP cycle, is beneficial when using oxide precursors, in order to remove volatiles and achieve high quality dense materials. Sample throughput can be increased significantly by utilising a high temperature ex-situ calcination prior to the HIP cycle. Investigation of glass-ceramic wasteform processing utilising a glass frit precursor, produced a phase assemblage and microstructure comparable to that obtained using oxide precursors. The use of a glass frit precursor should allow optimised throughput of waste packages in a production facility, avoiding the need for a calcination pre-treatment required to remove volatiles from oxide precursors. - Highlights: • Optimisation of pre-treatment parameters for HIP glass-ceramics was investigated. • Entrained porosity was minimised by ex-situ bake-out of oxide precursors at 600 °C. • Phase assemblage and microstructure proved independent of bake-out parameters. • Use of glass-frit precursor further improved process s throughput and simplification.

Microstructure and thermal conductivity of Mo-TiC cermets processed by hot isostatic pressing

International Nuclear Information System (INIS)

Le Flem, Marion; Allemand, Alexandre; Urvoy, Stephane; Cedat, Denis; Rey, Colette

2008-01-01

In the scope of refractory material development for structural applications in the core of future nuclear reactors (gas fast reactors working between 500 o C and at least 800 o C in nominal conditions and up to 1650 o C in accidental scenarios), five Mo-TiC cermets, and single-phase TiC and Mo, were processed by hot isostatic pressing. Starting TiC volume contents were 0%, 12.5%, 25%, 37.5%, 50%, 75% and 100%. First, high dense specimens were characterized in terms of microstructure, composition and phase volume fractions. Cermets exhibited two phases in agreement with phase diagram previsions (Mo-TiC 1-2at.% and TiC-Mo 10-15at.% ), and a residual non-reacted TiC-rich phase (TiC-Mo 1at.% ). Second, heat capacity and thermal diffusivity were measured up to 1000 o C which allowed to evaluate the thermal conductivity of each cermet: this lays between TiC conductivity (12-18 W/m K) and Mo conductivity (95-125 W/m K), thermal properties continuously decreasing with starting TiC content. An analytical approach based on the volume fraction and properties of each constituent allowed to highlight the existence of thermal resistance at the interphases at low temperature

Preliminary Study on Hot Isostatic Pressing Diffusion Bonding for CLAM Steel

International Nuclear Information System (INIS)

Chunjing Li; Qunying Huang; Yican Wu

2006-01-01

China Low Activation Martensitic (CLAM) steel is being developed in ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences) since three years ago. CLAM is selected as the major candidate structure materials for the FDS series design of fusion reactors and for China liquid metal LiPb Test Blanket Module (TBM) for ITER i.e. DFLL-TBM, which are being carried out in ASIPP. Since the hot isostatic pressing (HIP) bonding technique is one of the main candidate bonding techniques for manufacturing of the first wall of a fusion reactor, research of the HIP technique on CLAM/CLAM is greatly needed. Preliminary HIP diffusion bonding experiments on CLAM steel have been performed. A few machining approaches such as dry-milling, turnery and grounding etc. were used to prepare the sample surfaces and then they were degreased with a mixture of alcohol, ether and acetone in an ultrasonic bath. The samples were joined by HIP diffusion bonding with the compression pressure of 150 MPa and the holding time of 2 ∼ 3 hours under different temperatures between 950 deg. and 1100 deg.. Different seal techniques of the capsules were studied as well. Then appropriate post heat treatment was done. Tests on mechanical properties of the joints such as tensile strength and impact toughness have been performed. The preliminary results show that the tensile properties are roughly the same as those of the base material. The absorbed energy of the joints at present is a little low and further research is needed to increase it. Microstructure of the joints was studied by optical microscope, SEM and TEM. Compositions of the defects on the joining line were analyzed by EDS. Through analysis of the results, optimized parameters for HIP are given. (author)

Pre-Brazed Casting and Hot Radial Pressing: A Reliable Process for the Manufacturing of CFC and W Monoblock Mockups

International Nuclear Information System (INIS)

Visca, E.; Libera, S.; Mancini, A.; Mazzone, G.; Pizzuto, A.; Testani, C.

2006-01-01

ENEA association is involved in the European International Thermonuclear Experimental Reactor (ITER) R-and-D activities and in particular for the manufacturing of high heat flux plasma-facing components (HHFC), such as the divertor targets, the baffles and the limiters: During the last years ENEA has manufactured actively cooled mock-ups by using different technologies, namely brazing, diffusion bonding and hot isostatic pressing (HIPping). A new manufacturing process has been set up and tested. It was successfully applied for the manufacturing of W armoured monoblock mockups. This technique is the HRP (Hot Radial Pressing) based on performing a radial diffusion bonding between the cooling tube and the armour tile by pressurizing only the internal tube and by keeping the joining zone in vacuum and at the required bonding temperature. The heating is obtained by a standard air furnace. The next step was to apply the HRP technique for the manufacturing of CFC armoured monoblock components. For this purpose some issues have to be solved like as the low CFC tensile strength, the pure copper interlayer between the heat sink and the armour necessary to mitigate the stress at the joint interface and the low wettability of the pure copper on the CFC matrix. This paper reports the research path followed to manufacture a medium scale vertical target CFC and W armoured mockup by HRP. An ad hoc rig able to maintain the CFC in a compressive constant condition was also designed and tested. The casting of a soft copper interlayer between the tube and the tile was performed by a new technique: the Pre-Brazed Casting (PBC, ENEA patent). Some mock-ups with three NB31 CFC tiles were successfully manufactured and tested to thermal fatigue using electron beam facilities. They all reached at least 1000 cycles at 20 MW/m 2 without suffering any damage. The manufactured medium scale vertical target mock-up is now under testing at the FE2000 (France) facility. (author)

Experimental and Simulation Analysis of Hot Isostatic Pressing of Gas Atomized Stainless Steel 316L Powder Compacts

International Nuclear Information System (INIS)

Lin, Dongguo; Park, Seong Jin; Ha, Sangyul; Shin, Youngho; Park, Dong Yong; Chung, Sung Taek; Bollina, Ravi; See, Seongkyu

2016-01-01

In this work, both experimental and numerical studies were conducted to investigate the densification behavior of stainless steel 316L (STS 316L) powders during hot isostatic pressing (HIP), and to characterize the mechanical properties of HIPed specimens. The HIP experiments were conducted with gas atomized STS 316L powders with spherical particle shapes under controlled pressure and temperature conditions. The mechanical properties of HIPed samples were determined based on a series of tensile tests, and the results were compared to a reference STS 316L sample prepared by the conventional process, i.e., extrusion and annealing process. Corresponding microstructures before and after tensile tests were observed using scanning electron microscopy and their relationships to the mechanical properties were addressed. Furthermore, a finite element simulation based on the power-law creep model was carried out to predict the density distribution and overall shape change of the STS316L powder compact during HIP process, which agreed well with the experimental results.

Experimental and Simulation Analysis of Hot Isostatic Pressing of Gas Atomized Stainless Steel 316L Powder Compacts

Energy Technology Data Exchange (ETDEWEB)

Lin, Dongguo; Park, Seong Jin [Pohang University of Science and Technology, Pohang (Korea, Republic of); Ha, Sangyul [Samsung Electro-Mechanics, Suwon (Korea, Republic of); Shin, Youngho [Doosan Heavy Industries and Construction Co., Ltd., Changwon (Korea, Republic of); Park, Dong Yong [Korea Institute of Energy Research, Daejeon (Korea, Republic of); Chung, Sung Taek [CetaTech Inc., Sacheon (Korea, Republic of); Bollina, Ravi [Bahadurpally Jeedimetla, Hyderabad (India); See, Seongkyu [POSCO, Pohang (Korea, Republic of)

2016-10-15

In this work, both experimental and numerical studies were conducted to investigate the densification behavior of stainless steel 316L (STS 316L) powders during hot isostatic pressing (HIP), and to characterize the mechanical properties of HIPed specimens. The HIP experiments were conducted with gas atomized STS 316L powders with spherical particle shapes under controlled pressure and temperature conditions. The mechanical properties of HIPed samples were determined based on a series of tensile tests, and the results were compared to a reference STS 316L sample prepared by the conventional process, i.e., extrusion and annealing process. Corresponding microstructures before and after tensile tests were observed using scanning electron microscopy and their relationships to the mechanical properties were addressed. Furthermore, a finite element simulation based on the power-law creep model was carried out to predict the density distribution and overall shape change of the STS316L powder compact during HIP process, which agreed well with the experimental results.

Thermoelectric properties of I-doped n-type Bi2Te3-based material prepared by hydrothermal and subsequent hot pressing

Directory of Open Access Journals (Sweden)

Fang Wu

2017-04-01

Full Text Available I-doped Bi2Te3−xIx (x=0, 0.05, 0.1, 0.2 flower-like nanoparticles were synthesized by a hydrothermal method through a careful adjustment of the amount of ethylenediamine tetraacetic acid surfactant. The nanopowders of flower-like nanoparticles were hot-pressed into bulk pellets and the thermoelectric properties of the pellets were investigated. The results showed that I-doping decreased the electrical resistivity effectively, and the thermal conductivitives of the Bi2Te3−xIx bulk samples was lower because of the closer atomic mass of I compared to Te. As a result, a ZT value of 1.1 was attained at 448 K for the Bi2Te2.9I0.1 sample.

Influence of surface treatment of yttria-stabilized tetragonal zirconia polycrystal with hot isostatic pressing on cyclic fatigue strength.

Science.gov (United States)

Iijima, Toshihiko; Homma, Shinya; Sekine, Hideshi; Sasaki, Hodaka; Yajima, Yasutomo; Yoshinari, Masao

2013-01-01

Hot isostatic pressing processed yttria-stabilized tetragonal zirconia polycrystal (HIP Y-TZP) has the potential for application to implants due to its high mechanical performance. The aim of this study was to investigate the influence of surface treatment of HIP Y-TZP on cyclic fatigue strength. HIP Y-TZP specimens were subjected to different surface treatments. Biaxial flexural strength was determined by both static and cyclic fatigue testing. In the cyclic fatigue test, the load was applied at a frequency of 10 Hz for 10(6) cycles in distilled water at 37°C. The surface morphology, roughness, and crystal phase of the surfaces were also evaluated. The cyclic fatigue strength (888 MPa) of HIP Y-TZP with sandblasting and acid-etching was more than twice that of Y-TZP as specified in ISO 13356 for surgical implants (320 MPa), indicating the clinical potential of this material.

Effect of Hot-isostatic Pressing on Microstructure and Mechanical Properties of Second Generation Single Crystal Superalloy DD6

Directory of Open Access Journals (Sweden)

GUO Hui-ming

2016-10-01

Full Text Available Effects of the hot-isostatic pressing (HIP temperature (1280,1300,1320℃ on microstructures and mechanical properties of a second generation single crystal superalloy DD6 were investigated. The results show that the HIP treatment significantly decrease the cast porosity number of DD6 compared with standard treated specimens. Especially, the cast porosity volume fraction is deceased from 0.31% to 0.04% after the HIP treatment of 1300℃/100MPa, 4h. The cast eutectic volume fractions are remarkably reduced with increasing HIP temperature. The HIP treatments nearly unchanged the creep lives, While they greatly promote the low cycle fatigue lives. The elimination of cast microspores using the HIP treatment of 1300℃/100MPa, 4h result in the inhibition of crack initiation during fatigue and improve the low cycle fatigue lives one order of magnitude larger than that after standard heat treatment.

Kaji Eksperimental dan Simulasi Ansys 14.5 Perlakuan Serat Tandan Kosong Kelapa Sawit Serta Pembuatan Komposit Busa Polimer pada Proses Hot Press Menggunakan Alat Uji Tarik

OpenAIRE

Ginting, Enda Prananta

2016-01-01

Along the innovations of the field of materials, natural fibers are used as reinforcement materials composite which are the fibers greatly affect and determine the strength of the composite. This experimental study reported the empty fruit bunches of oil palm fiber’s treatment process and manufacture of polymeric foam composite spesimens in the process of hot press machine followed by a tensile test. The issues, that characteristic of composites reinforced fibers has a light weight and relati...

Interfacial layers evolution during annealing in Ti-Al multi-laminated composite processed using hot press and roll bonding

Science.gov (United States)

Assari, A. H.; Eghbali, B.

2016-09-01

Ti-Al multi-laminated composites have great potential in high strength and low weight structures. In the present study, tri-layer Ti-Al composite was synthesized by hot press bonding under 40 MPa at 570 °C for 1 h and subsequent hot roll bonding at about 450 °C. This process was conducted in two accumulative passes to 30% and to 67% thickness reduction in initial and final passes, respectively. Then, the final annealing treatments were done at 550, 600, 650, 700 and 750 °C for 2, 4 and 6 h. Investigations on microstructural evolution and thickening of interfacial layers were performed by scanning electron microscopes, energy dispersive spectrometer, X-ray diffraction and micro-hardness tests. The results showed that the thickening of diffusion layers corresponds to amount of deformation. In addition to thickening of the diffusion layers, the thickness of aluminum layers decreased and after annealing treatment at 750 °C for 6 h the aluminum layers were consumed entirely, which occurred because of the enhanced interdiffusion of Ti and Al elements. Scanning electron microscope equipped with energy dispersive spectrometer showed that the sequence of interfacial layers as Ti3Al-TiAl-TiAl2-TiAl3 which are believed to be the result of thermodynamic and kinetic of phase formation. Micro-hardness results presented the variation profile in accordance with the sequence of intermetallic phases and their different structures.

Evaluation of hot forming effects mapping for CAE analyses

Science.gov (United States)

Knoerr, L.; Faath, T.; Dykeman, J.; Malcolm, S.

2016-08-01

Hot forming has grown significantly in the manufacturing of structural components within the vehicle Body-In-White construction. The superior strength of press hardened steels not only guarantee high resistance to deformation, it also brings a significant weight saving compared to conventional cold formed products. However, the benefit of achieving ultrahigh strength with hot stamping, comes with a reduction in ductility of the press hardened part. This will require advanced material modeling to capture the predicted performances accurately. A technique to optically measure and map the thinning distribution after hot stamping has shown to improve numerical analysis for fracture prediction. The proposed method to determine the forming effects and mapping to CAE models can be integrated into the Vehicle Development Process to shorten the time to production.

Investigation of Wear Behavior of Aluminum Matrix Composite Reinforced by Al2O3 and Produced by Hot Pressing Process

Directory of Open Access Journals (Sweden)

Halil ARIK

2017-12-01

Full Text Available In this study, Al powder produced by gas atomization technique has 72.06 µm average particle size and 99 % purity was mixed with as a reinforcement Al2O3 has 99.52% purity and 45 submicron particle size in a high energy ball mill for two hours. In order to obtain disk samples with 30 mm diameter and 6 mm thick mixed powders, after the characterization of particle size and morphology, were compacted in a single action press. Compaction process were carried out from mixed powders by hot pressing at 200 MPa pressure and 550 °C temperature for two hours. Then microstructural analysis, hardness and density measurements of powder metal composite parts were performed. After, the characterization of samples abrasion wear tests were performed according to ASTM-G99-05 by using TRIBOMETER T10/20 ball-on-disk abrasive wearing device. After the abrasive wear test of aluminum and composite powder metal parts produced under the identical test parameters, test results were compared and effect of Al2O3 on the wear properties of composite materials was exhibited. The test results showed that the composite parts have 62 % extra harness and better abrasion wear performance according to aluminum powder metal parts produced and tested under the identical conditions

Tensile Fracture Behavior of 316L Austenitic Stainless Steel Manufactured by Hot Isostatic Pressing

Science.gov (United States)

Cooper, A. J.; Brayshaw, W. J.; Sherry, A. H.

2018-02-01

Herein we investigate how the oxygen content in hot isostatically pressed (HIP'd) 316L stainless steel affects the mechanical properties and tensile fracture behavior. This work follows on from previous studies, which aimed to understand the effect of oxygen content on the Charpy impact toughness of HIP'd steel. We expand on the work by performing room-temperature tensile testing on different heats of 316L stainless steel, which contain different levels of interstitial elements (carbon and nitrogen) as well as oxygen in the bulk material. Throughout the work we repeat the experiments on conventionally forged 316L steel as a reference material. The analysis of the work indicates that oxygen does not contribute to a measureable solution strengthening mechanism, as is the case with carbon and nitrogen in austenitic stainless steels (Werner in Mater Sci Eng A 101:93-98, 1988). Neither does oxygen, in the form of oxide inclusions, contribute to precipitation hardening due to the size and spacing of particles. However, the oxide particles do influence fracture behavior; fractography of the failed tension test specimens indicates that the average ductile dimple size is related to the oxygen content in the bulk material, the results of which support an on-going hypothesis relating oxygen content in HIP'd steels to their fracture mechanisms by providing additional sites for the initiation of ductile damage in the form of voids.

Effect of rapid solidification on the microstructure and mechanical properties of hot-pressed Al-20Si-5Fe alloys

International Nuclear Information System (INIS)

Rajabi, M.; Vahidi, M.; Simchi, A.; Davami, P.

2009-01-01

The aim of this work is to study the effect of cooling rate and subsequent hot consolidation on the microstructural features and mechanical strength of Al-20Si-5Fe-2X (X = Cu, Ni and Cr) alloys. Powder and ribbons were produced by gas atomization and melt spinning processes at two different cooling rates of 1 x 10 5 K/s and 5 x 10 7 K/s. The microstructure of the products was examined using optical microscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The particles were consolidated by hot pressing at 400 deg. C/250 MPa/1 h under a high purity argon atmosphere and the microstructure, hardness and compressive strength of the compacts were evaluated. Results showed a profound effect of the cooling rate, consolidation stage, and transition metals on the microstructure and mechanical strength of Al-20Si-5Fe alloys. While microstructural refining was obtained at both cooling rates, the microstructure of the atomized powder exhibited the formation of fine primary silicon (∼ 1 μm), eutectic Al-Si phase with eutectic spacing of ∼ 300 nm, and δ-iron intermetallic. Supersaturated Al matrix containing 5-7 at.% silicon and nanometric Si precipitates (20-40 nm) were determined in the microstructure of the melt-spun ribbons. The hot consolidation resulted in coarsening of Si particles in the atomized particles, and precipitation of Si and Fe-containing intermetallics from the supersaturated Al matrix in the ribbons. The consolidated ribbons exhibited higher mechanical strength compared to the atomized powders, particularly at elevated temperatures. The positive influence of the transition metals on the thermal stability of the Al-20Si-5Fe alloy was noticed, particularly in the Ni-containing alloy.

Pre-brazed casting and hot radial pressing: A reliable process for the manufacturing of CFC and W monoblock mock-ups

Energy Technology Data Exchange (ETDEWEB)

Visca, Eliseo [Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, Via E. Fermi, 45, IT-00044 Frascati, RM (Italy)], E-mail: visca@frascati.enea.it; Libera, S.; Mancini, A.; Mazzone, G.; Pizzuto, A. [Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, Via E. Fermi, 45, IT-00044 Frascati, RM (Italy); Testani, C. [CSM S.p.A., IT-00128 Castel Romano, RM (Italy)

2007-10-15

ENEA is involved in the European International Thermonuclear Experimental Reactor (ITER) R and D activities and, in particular, for the manufacturing of high heat flux plasma-facing components (HHFC), such as the divertor targets, the baffles and the limiters. During last years, ENEA has manufactured actively cooled mock-ups by using different technologies, namely brazing, diffusion bonding and hot isostatic pressing (HIPping). A new manufacturing process has been set up and tested. It was successfully applied for the manufacturing of W armoured monoblock mock-ups. This technique is the HRP (hot radial pressing) based on performing a radial diffusion bonding between the cooling tube and the armour tile by pressurizing only internal tube and by keeping the joining zone in vacuum at the required bonding temperature. The heating is obtained by a standard air furnace. The HRP technique is now used for the manufacturing of CFC armoured monoblock components. For this purpose, some issues have to be faced, like the low CFC tensile strength, the pure copper interlayer between the heat sink and the armour necessary to mitigate the stress at the joint interface, and the low wettability of the pure copper on the CFC matrix. This paper reports the research path followed to manufacture a medium scale vertical target CFC and W armoured mock-up by HRP. A casting of a soft copper interlayer between the tube and the tile was obtained by a new technique: the pre-brazed casting (PBC, ENEA patent). Some preliminary mock-ups with three NB31 CFC tiles were successfully manufactured and tested to thermal fatigue using electron beam facilities. They all reached at least 1000 cycles at 20 MW/m{sup 2} without suffering any damage. The manufactured medium scale vertical target mock-up is now under testing at the FE2000 (France) facility. These activities were performed in the frame of ITER-EFDA contracts.

Effect of sintering temperature and boron carbide content on the wear behavior of hot pressed diamond cutting segments

Directory of Open Access Journals (Sweden)

Islak S.

2015-01-01

Full Text Available The aim of this study was to investigate the effect of sintering temperature and boron carbide content on wear behavior of diamond cutting segments. For this purpose, the segments contained 2, 5 and 10 wt.% B4C were prepared by hot pressing process carried out under a pressure of 35 MPa, at 600, 650 and 700 °C for 3 minutes. The transverse rupture strength (TRS of the segments was assessed using a three-point bending test. Ankara andesite stone was cut to examine the wear behavior of segments with boron carbide. Microstructure, surfaces of wear and fracture of segments were determined by scanning electron microscopy (SEM-EDS, and X-ray diffraction (XRD analysis. As a result, the wear rate decreased significantly in the 0-5 wt.% B4C contents, while it increased in the 5-10 wt.% B4C contents. With increase in sintering temperature, the wear rate decreased due to the hard matrix.

Enhancement of mechanical strength in hot-pressed TiB2 composites by the addition of Fe and Ni

International Nuclear Information System (INIS)

Yen, C.F.; Yust, C.S.; Clark, G.W.

1978-01-01

Improvement in the fracture strength of TiB 2 composites through the addition of Fe and Ni is reported. Beam specimens containing up to 20 wt % of the metal component were fabricated by hot pressing above the eutectic temperature. Four point bending results indicated that the observed enhancement in strength was proportional to the vol % of the metal present. The results also revealed that TiB 2 --Ni composites have slightly better strength than TiB 2 --Fe samples at elevated temperatures, and that their strengths were consistently about twice that of pure TiB 2 . They also did not exhibit any serious degradation in strength up to 700 0 C. The fracture behavior was characterized using optical and scanning electron microscopy. The strengthening appears to be related to the presence of a metallic grain boundary phase between TiB 2 particles. The results further suggested that the formation of a special eutectic-like grain microstructure could render additional strengthening

Formation of ultra-fine grained TiC-dispersed SUS316L by ball-milling and their consolidation by hot isostatic pressing

International Nuclear Information System (INIS)

Zheng, Yongjia; Yamasaki, Tohru; Fukami, Takeshi; Mitamura, Tohru; Terasawa, Mititaka

2003-01-01

In order to overcome the irradiation embrittlement in austenitic stainless steels, ultra-fine grained SUS316L steels with very fine TiC particles have been developed. The SUS316-TiC nanocomposite powders having 1.0 to 2.0 mass%TiC were prepared by ball-milling SUS316-TiC powder mixtures for 125h in an argon gas atmosphere. The milled powders were consolidated by hot isostatic pressing (HIP) under a pressure of 200 MPa at temperature between 700-1000degC, and the bulk materials with crystallite size ranging between 100-400 nm have been produced. The possibility of using fine-grained TiC particles for pinning grain boundaries and thereby to maintain the ultra-fine grained structures has been discussed. (author)

Ultrasonic assisted hot metal powder compaction.

Science.gov (United States)

Abedini, Rezvan; Abdullah, Amir; Alizadeh, Yunes

2017-09-01

Hot pressing of metal powders is used in production of parts with similar properties to wrought materials. During hot pressing processes, particle rearrangement, plastic deformation, creep, and diffusion are of the most effective powder densification mechanisms. Applying ultrasonic vibration is thought to result in great rates of densification and therefore higher efficiency of the process is expected. This paper deals with the effects of power ultrasonic on the densification of AA1100 aluminum powder under constant applied stress. The effects of particle size and process temperature on the densification behavior are discussed. The results show that applying ultrasonic vibration leads to an improved homogeneity and a higher relative density. Also, it is found that the effect of ultrasonic vibration is greater for finer particles. Copyright © 2016 Elsevier B.V. All rights reserved.

The effect of cushion-ram pulsation on hot stamping

Science.gov (United States)

Landgrebe, Dirk; Rautenstrauch, Anja; Kunke, Andreas; Polster, Stefan; Kriechenbauer, Sebastian; Mauermann, Reinhard

2016-10-01

Hot stamping is an important technology for manufacturing high-strength components. This technology offers the possibility to achieve significant weight reductions. In this study, cushion-ram pulsation (CRP), a new technology for hot stamping on servo-screw presses, was investigated and applied for hot stamping. Compared to a conventional process, the tests yielded a significantly higher drawing depth. In this paper, the CRP technology and the first test results with hot stamping were described in comparison to the conventional process.

Effect of heat treatment and hot isostatic pressing on the microstructure and mechanical properties of Inconel 625 alloy processed by laser powder bed fusion

Energy Technology Data Exchange (ETDEWEB)

Kreitcberg, Alena, E-mail: alena.kreitcberg.1@ens.etsmtl.ca [École de technologie supérieure, 110 Notre-Dame Street West, Montreal, Quebec H3C 1K3 Canada (Canada); Brailovski, Vladimir, E-mail: vladimir.brailovski@etsmtl.ca [École de technologie supérieure, 110 Notre-Dame Street West, Montreal, Quebec H3C 1K3 Canada (Canada); Turenne, Sylvain, E-mail: sylvain.turenne@polymtl.ca [École Polytechnique de Montréal, 2900 boul. Édouard-Montpetit, Montreal, Quebec H3T 1J4 Canada (Canada)

2017-03-24

The effect of different heat treatments and hot isostatic pressing on the microstructure and mechanical properties of laser powder bed fusion IN625 alloy was studied. The heat treatments were: stress relief annealing, recrystallization annealing and low-temperature solution treatment. The resulting microstructure and crystallographic textures were studied using optical and scanning electron microscopy. The mechanical properties of the as-built and post-treated IN625 alloy were obtained after tensile testing at room temperature and at 760 °C (1400 °F), and compared to those of an annealed wrought alloy of the same composition.

Hot-working behavior of cast Pr-Fe-B magnets

International Nuclear Information System (INIS)

Shimoda, T.; Akioka, K.; Kobayashi, O.; Yamagami, T.; Ohki, T.; Miyagawa, M.; Yuri, T.

1989-01-01

The hot-working behavior of cast Pr-Fe-B magnets is investigated. The hot-working is done both at a low strain rate (hot-pressing) and a high strain rate (hot-rolling). Magnetic alignment induced by the hot-working is found to be closely related to the macrostructure of the cast ingots and the direction of principal stress. The appropriate structure is a columnar structure. The c-axis of the Pr2Fe14B phase is lying in the plane perpendicular to the growth direction of the dendrites. The principal stress during working should be given perpendicular to the growth direction

Influence of Powder Surface Contamination in the Ni-Based Superalloy Alloy718 Fabricated by Selective Laser Melting and Hot Isostatic Pressing

Directory of Open Access Journals (Sweden)

Yen-Ling Kuo

2017-09-01

Full Text Available The aim of this study was to gain a deep understanding of the microstructure-mechanical relationship between solid-state sintering and full-melting processes. The IN718 superalloy was fabricated by hot isostatic pressing (HIP and selective laser melting (SLM. Continuous precipitates were clearly localized along the prior particle boundary (PPB in the HIP materials, while SLM materials showed a microstructure free of PPB. The mechanical properties of specimens that underwent SLM + solution treatment and aging were comparable to those of conventional wrought specimens both at room temperature and 650 °C. However, a drop was observed in the ductility of HIP material at 650 °C. The brittle particles along the PPB were found to affect the HIP materials’ creep life and ductility during solid-state sintering.

Void formation in ODS EUROFER produced by hot isostatic pressing

Energy Technology Data Exchange (ETDEWEB)

Ortega, Y.; Monge, M.A.; Munoz, A.; Leguey, T.; Pareja, R. [Madrid Univ. Carlos-3, Dept. de Fisica (Spain); Castro, V. de [Oxford Univ., Dept. of Materials (United Kingdom)

2007-07-01

Full text of publication follows: An obstacle in the development of oxide dispersion strengthened (ODS) steels for structural applications in fusion reactors is the toughness lack of the material produced by powder metallurgy and consolidated by hot isostatic pressing (HIP). In particular, ODS EUROFER steel with Y{sub 2}O{sub 3} particles appears to exhibit poor impact properties. To asses the capabilities of this material, it is necessary elucidate if its failure is an inherent characteristic of the production process that can not be mitigated by normalizing and tempering treatments. In order to investigate this particular point, the evolution of the structural defects retained in the ODS material during isochronal annealing has been probed by positron annihilation spectroscopy. The present study has been performed on bail milled EUROFER powders consolidated by HIP, containing 0.25 wt % Y{sub 2}O{sub 3} and without Y{sub 2}O{sub 3}. For comparison, un-milled EUROFER powder consolidated under identical conditions, and as-received EUROFER97 plate produced by Boehler AG have been also investigated. Samples from these four materials were isochronally annealed for 90 min up to 1323 K. Materials produced from milled powders had a longer positron lifetime than the one produced from un-milled powder or the EUROFER plate. In the material containing Y{sub 2}O{sub 3}, i.e. in ODS EUROFER, annealing above 723 K produced a continuous increase in the mean positron lifetime <{tau}> up to reach a maximum value of 208 ps after annealing at 1223 K. A similar annealing behavior was observed for Y{sub 2}O{sub 3}-free milled EUROFER (milled EUROFER), but the <{tau}> value steeply changed from {approx}160 ps at 823 K to {approx}200 ps after annealing at 1023 K. Subsequent anneals above this temperature produced meaningless changes in <{tau}>. The <{tau}> increase in milled EUROFER was accompanied by the intensity increase of a lifetime component of {approx}360 ps that is characteristic

Prototype Development of Remote Operated Hot Uniaxial Press (ROHUP) to Fabricate Advanced Tc-99 Bearing Ceramic Waste Forms - 13381

Energy Technology Data Exchange (ETDEWEB)

Alaniz, Ariana J.; Delgado, Luc R.; Werbick, Brett M. [University of Nevada - Las Vegas, Howard R. Hughes College of Engineering, 4505 S. Maryland Parkway, Box 454009, Las Vegas, NV 89154-4009 (United States); Hartmann, Thomas [University of Nevada - Las Vegas, Harry Reid Canter, 4505 S. Maryland Parkway, Box 454009, Las Vegas, NV 89154-4009 (United States)

2013-07-01

The objective of this senior student project is to design and build a prototype construction of a machine that simultaneously provides the proper pressure and temperature parameters to sinter ceramic powders in-situ to create pellets of rather high densities of above 90% (theoretical). This ROHUP (Remote Operated Hot Uniaxial Press) device is designed specifically to fabricate advanced ceramic Tc-99 bearing waste forms and therefore radiological barriers have been included in the system. The HUP features electronic control and feedback systems to set and monitor pressure, load, and temperature parameters. This device operates wirelessly via portable computer using Bluetooth{sup R} technology. The HUP device is designed to fit in a standard atmosphere controlled glove box to further allow sintering under inert conditions (e.g. under Ar, He, N{sub 2}). This will further allow utilizing this HUP for other potential applications, including radioactive samples, novel ceramic waste forms, advanced oxide fuels, air-sensitive samples, metallic systems, advanced powder metallurgy, diffusion experiments and more. (authors)

A study on improving mechanical properties of porous HA tissue engineering scaffolds by hot isostatic pressing

International Nuclear Information System (INIS)

Zhao Jing; Xiao Suguang; Lu Xiong; Wang Jianxin; Weng Jie

2006-01-01

Various interconnected porous hydroxyapatite (HA) ceramic scaffolds are universally used to induct the tissue growth for bone repair and replacement, and serve to support the adhesion, transfer, proliferation and differentiation of cells. Impregnation of polyurethane sponges with a ceramic slurry is adopted to produce highly porous HA ceramic scaffolds with a 3D interconnected structure. However, high porosity always accompanies a decrease in the strength of the HA ceramic scaffolds. Therefore, it is significant to improve the strength of the HA ceramic scaffolds with highly interconnected porosity so that they are more suitable in clinical applications. In this work, highly porous HA ceramic scaffolds are first produced by the polymer impregnation approach, and subsequently further sintered by hot isostatic pressing (HIP). The phase composition, macro- and micro-porous structure, sintering and mechanical properties of the porous HA scaffolds are investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), nanoindentation analysis and compressive test. The experimental results show that the nanohardness and compressive strength of HIP-sintered porous HA ceramics are higher than those of commonly sintered HA scaffolds. The HIP technique can effectively improve the sintering property and densification of porous HA ceramic scaffolds, so inducing an increase in the compression strength

Study on the isothermal oxidation behavior in air of Ti3AlC2 sintered by hot pressing

Institute of Scientific and Technical Information of China (English)

XU Xuewen; LI Yangxian; MEI Bingchu; ZHU Jiaoqun; LIU Heyan; QU Jingping

2006-01-01

The isothermal oxidation behavior at 900―1300℃ for 20 h in air of bulk Ti3AlC2 with 2.8 wt% TiC sintered by means of hot pressing was investigated in the work. The isothermal oxidation behavior generally followed a parabolic rate law. The parabolic rate constants increased from 1.39×10-10 kg2·m-4·s-1 at 900℃ to 5.56×10-9 kg2·m-4·s-1 at 1300℃. The calculated activation energy was 136.45 kJ/mol. It was demonstrated that Ti3AlC2 had excellent oxidation resistance due to the continuous, dense and adhesive protect scales consisted of a mass of α-Al2O3 and a little of TiO2 and/or Al2TiO5. In principle, the oxide scale was grown by the inward diffusion of O2- and the outward diffusion of Ti4+ and Al3+. The rapid outward diffusion of cations usually resulted in the formation of cracks, gaps, and holes.

Thermoelectric Properties of Cu-doped Bi2-xSbxTe3 Prepared by Encapsulated Melting and Hot Pressing

Science.gov (United States)

Jung, Woo-Jin; Kim, Il-Ho

2018-03-01

P-type Bi2-xSbxTe3:Cum (x = 1.5-1.7 and m = 0.002-0.003) solid solutions were synthesized using encapsulated melting and were consolidated using hot pressing. The effects of Sb substitution and Cu doping on the charge transport and thermoelectric properties were examined. The lattice constants decreased with increasing Sb and Cu contents. As the amount of Sb substitution and Cu doping was increased, the electrical conductivity increased, and the Seebeck coefficient decreased owing to the increase in the carrier concentration. All specimens exhibited degenerate semiconductor characteristics and positive Hall and Seebeck coefficients, indicating p-type conduction. The increased Sb substitution caused a shift in the onset temperature of the intrinsic transition and bipolar conduction to higher temperatures. The electronic thermal conductivity increased with increasing Sb and Cu contents owing to the increase in the carrier concentration, while the lattice thermal conductivity slightly decreased due to alloy scattering. A maximum figure of merit, ZTmax = 1.25, was achieved at 373 K for Bi0.4Sb1.6Te3:Cu0.003.

Sensitivity Characterization of Pressed Energetic Materials using Flyer Plate Mesoscale Simulations

Science.gov (United States)

Rai, Nirmal; Udaykumar, H. S.

Heterogeneous energetic materials like pressed explosives have complicated microstructure and contain various forms of heterogeneities such as pores, micro-cracks, energetic crystals etc. It is widely accepted that the presence of these heterogeneities can affect the sensitivity of these materials under shock load. The interaction of shock load with the microstructural heterogeneities may leads to the formation of local heated regions known as ``hot spots''. Chemical reaction may trigger at the hot spot regions depending on the hot spot temperature and the duration over which the temperature can be maintained before phenomenon like heat conduction, rarefaction waves withdraws energy from it. There are different mechanisms which can lead to the formation of hot spots including void collapse. The current work is focused towards the sensitivity characterization of two HMX based pressed energetic materials using flyer plate mesoscale simulations. The aim of the current work is to develop mesoscale numerical framework which can perform simulations by replicating the laboratory based flyer plate experiments. The current numerical framework uses an image processing approach to represent the microstructural heterogeneities incorporated in a massively parallel Eulerian code SCIMITAR3D. The chemical decomposition of HMX is modeled using Henson-Smilowitz reaction mechanism. The sensitivity characterization is aimed towards obtaining James initiation threshold curve and comparing it with the experimental results.

Fabrication and Analysis of the Wear Properties of Hot-Pressed Al-Si/SiCp + Al-Si-Cu-Mg Metal Matrix Composite

Science.gov (United States)

Bang, Jeongil; Oak, Jeong-Jung; Park, Yong Ho

2016-01-01

The aim of this study was to characterize microstructures and mechanical properties of aluminum metal matrix composites (MMC's) prepared by powder metallurgy method. Consolidation of mixed powder with gas atomized Al-Si/SiCp powder and Al-14Si-2.5Cu-0.5Mg powder by hot pressing was classified according to sintering temperature and sintering time. Sintering condition was optimized using tensile properties of sintered specimens. Ultimate tensile strength of the optimized sintered specimen was 228 MPa with an elongation of 5.3% in longitudinal direction. In addition, wear properties and behaviors of the sintered aluminum-based MMC's were analyzed in accordance with vertical load and linear speed. As the linear speed and vertical load of the wear increased, change of the wear behavior occurred in order of oxidation of Al-Si matrix, formation of C-rich layer, Fe-alloying to matrix, and melting of the specimen

Al_2O_3/PVdF-HFP-CMC/PE separator prepared using aqueous slurry and post-hot-pressing method for polymer lithium-ion batteries with enhanced safety

International Nuclear Information System (INIS)

Deng, Yaoming; Song, Xiaona; Ma, Zhen; Zhang, Xinhe; Shu, Dong; Nan, Junmin

2016-01-01

A composite separator is prepared to improve the safety of lithium ion batteries (LIBs) based on a gravure coating aqueous slurry and post-hot-pressing method. An environmentally friendly aqueous slurry with an Al_2O_3 ceramic holder and polyvinylidene difluoride-hexafluoropropylene (PVdF-HFP) and carboxymethyl cellulose (CMC) dual-binders is coated on a polyolefin (PE) substrate to form a prototype Al-PHC/PE separator. Then, after assembling the separator in the batteries and hot-pressing at 70 °C and 0.8 MPa for 3 h, the granular PVdF-HFP is transformed into a colloidal structure containing an electrolyte, which can binds the Al_2O_3 nanoparticles together and increases the battery hardness. Compared with a PE separator (9 μm), the Al-PHC/PE-2 separator (12 μm, with a Al_2O_3/PVdF-HFP weight ratio of 7/3) displays a comparative ionic conductivity of 9.3 × 10"−"4 S cm"−"2 and exhibits no obvious thermal deformation at 110 °C for 60 min. All of the batteries assembled with Al-PHC/PE-2 separators passed nail penetration and impact tests. In addition, the capacity retention increases from 83.4% to 87.6% when the battery is assembled with Al-PHC/PE-2 instead of a PE separator and charge-discharged at 0.7C/1.0C for 350 cycles. The enhanced safety and cycle performance indicate the promising prospect of Al-PHC/PE separators in LIBs.

Development of Duplex Stainless Steels by Field-Assisted Hot Pressing: Influence of the Particle Size and Morphology of the Powders on the Final Mechanical Properties

Science.gov (United States)

García-Junceda, A.; Rincón, M.; Torralba, J. M.

2018-01-01

The feasibility of processing duplex stainless steels with promising properties using a powder metallurgical route, including the consolidation by field-assisted hot pressing, is assessed in this investigation. The influence of the particle size and morphology of the raw austenitic and ferritic powders on the final microstructure and properties is also evaluated for an austenitic content of 60 wt pct. In addition, the properties of a new microconstituent generated between the initial constituents are analyzed. The maximum sintered density (98.9 pct) and the best mechanical behavior, in terms of elastic modulus, nanohardness, yield strength, ultimate tensile strength, and ductility, are reached by the duplex stainless steel processed with austenitic and ferritic gas atomized stainless steel powders.

Effects of internal gas pressure and microstructure on the mechanisms of hot-pressing and swelling in ceramics. Final report, June 1, 1979-May 31, 1980

International Nuclear Information System (INIS)

Solomon, A.A.

1980-08-01

The results of the study of the effects of internal and external gas pressures on ceramics are summarized. The new experimental systems for studying these phenomena are described. The study has shown that the rate of volume change in ZnO is linearly related to the total pressure driving force. Swelling and hot-pressing can be described on a consistent basis in terms of this driving force. For ZnO, Ni and UO 2 the rate of volume change is dependent on bulk diffusion. The porosity evolution during swelling is described and the resintering phenomenon is identified. Various models for pore growth and shrinkage are considered and related to the behavior of the different systems

Production of an impermeable composite of irradiated graphite and glass by hot isostatic pressing as a long term leach resistant waste form

International Nuclear Information System (INIS)

Fachinger, Johannes; Muller, Walter; Marsat, Eric; Grosse, Karl-Heinz; Seemann, Richard; Scales, Charlie; Easton, Michael Mark; Anthony Banford

2013-01-01

Around 250,000 tons of irradiated graphite (i-graphite) exists worldwide and can be considered as a current waste or future waste stream. The largest national i-graphite inventory is located in UK (∼ 100,000 tons) with significant quantities also in Russia and France [5]. Most of the i-graphite remains in the cores of shutdown nuclear reactors including the MAGNOX type in UK and the UNGG in France. Whilst there are still operational power reactors with graphite cores, such as the Russian RBMKs and the AGRs in UK, all of them will reach their end of life during the next two decades. The most common reference waste management option of i-graphite is a wet or dry retrieval of the graphite blocks from the reactor core and the grouting of these blocks in a container without further conditioning. This produces large waste package volumes because the encapsulation capacity of the grout is limited and large cavities in the graphite blocks could reduce the packing densities. Packing densities from 0.5 to 1 tons per cubic meter have been assumed for grouting solutions. Furthermore the grout is permeable. This could over time allow the penetration of aqueous phases into the waste block and a potential dissolution and release of radionuclides. As a result particularly highly soluble radionuclides may not be retained by the grout. Vitrification could present an alternative, however a similar waste package volume increase may be expected since the encapsulation capacity of glass is potentially similar to or worse than that of grout. FNAG has developed a process for the production of a graphite-glass composite material called Impermeable Graphite Matrix (IGM) [3]. This process is also applicable to irradiated graphite which allows the manufacturing of an impermeable material without volume increase. Crushed i-graphite is mixed with 20 vol.% of glass and then pressed under vacuum at an elevated temperature in an axial hot vacuum press (HVP). The obtained product has zero or

Production of an impermeable composite of irradiated graphite and glass by hot isostatic pressing as a long term leach resistant waste form

Energy Technology Data Exchange (ETDEWEB)

Fachinger, Johannes; Muller, Walter [FNAG ZU Hanau, Hanau (Germany); Marsat, Eric [FNAG SAS Le Pont de Claix (France); Grosse, Karl-Heinz; Seemann, Richard [ALD Hanau (Germany); Scales, Charlie; Easton, Michael Mark [NNL, Workington (United Kingdom); Anthony Banford [NNL, Warrington (United Kingdom); University of Manchester, Manchester (United Kingdom)

2013-07-01

Around 250,000 tons of irradiated graphite (i-graphite) exists worldwide and can be considered as a current waste or future waste stream. The largest national i-graphite inventory is located in UK (∼ 100,000 tons) with significant quantities also in Russia and France [5]. Most of the i-graphite remains in the cores of shutdown nuclear reactors including the MAGNOX type in UK and the UNGG in France. Whilst there are still operational power reactors with graphite cores, such as the Russian RBMKs and the AGRs in UK, all of them will reach their end of life during the next two decades. The most common reference waste management option of i-graphite is a wet or dry retrieval of the graphite blocks from the reactor core and the grouting of these blocks in a container without further conditioning. This produces large waste package volumes because the encapsulation capacity of the grout is limited and large cavities in the graphite blocks could reduce the packing densities. Packing densities from 0.5 to 1 tons per cubic meter have been assumed for grouting solutions. Furthermore the grout is permeable. This could over time allow the penetration of aqueous phases into the waste block and a potential dissolution and release of radionuclides. As a result particularly highly soluble radionuclides may not be retained by the grout. Vitrification could present an alternative, however a similar waste package volume increase may be expected since the encapsulation capacity of glass is potentially similar to or worse than that of grout. FNAG has developed a process for the production of a graphite-glass composite material called Impermeable Graphite Matrix (IGM) [3]. This process is also applicable to irradiated graphite which allows the manufacturing of an impermeable material without volume increase. Crushed i-graphite is mixed with 20 vol.% of glass and then pressed under vacuum at an elevated temperature in an axial hot vacuum press (HVP). The obtained product has zero or

Exercise in Experimental Plastics Technology: Hot Embossing of Polymers with surface microstructure

DEFF Research Database (Denmark)

Eriksson, Torbjörn Gerhard; Rasmussen, Henrik Koblitz

2004-01-01

Hot Embossing of polymers with surface microstructure Polymer materials have proven to be good materials for manufacturing nano/ and microstructure. There are three major processing techniques: hot embossing, injection moulding and casting. Hot embossing provides several advantages such as relati......Hot Embossing of polymers with surface microstructure Polymer materials have proven to be good materials for manufacturing nano/ and microstructure. There are three major processing techniques: hot embossing, injection moulding and casting. Hot embossing provides several advantages...... such as relatively low cost for embossing tools, simple operation and high replication accuracy for small features. Two different plastic materials will be used to replicate surface microstructures by hot embossing. The hot embossing will be done in a hydraulic press where it is easy to control temperature...

Structure and properties of hot-pressed boron carbide ceramics

Energy Technology Data Exchange (ETDEWEB)

Koval' chenko, M S; Tkachenko, IU G; Koval' chuk, V V; Iurchenko, D Z; Satanin, S V [Institut Problem Materialovedeniia, Kiev (Ukrainian SSR)

1990-07-01

The microstructure and strength of B4C-TiB2-TiO{sub 2} ceramics samples, hot-compacted from a mixture of two types of B4C-TiO2-C powder, are examined. The two types are obtained by combining boric acid with either sucrose or carbon black. The grain-sizes of the two powders are found to be distinctly different from one another both before and after the grinding procedure and the degree of dispersion is not high. The strength tests show 600 MPa, the Vicker's hardness is 34.5 GPa, and the crack resistance coefficient of ceramics containing 15 percent TiB2 by mass is 5 MPa m exp 1/2. The use of soluble boron carbide powder helps achieve higher levels of strength and crack resistance. 5 refs.

Prediction of Pressing Quality for Press-Fit Assembly Based on Press-Fit Curve and Maximum Press-Mounting Force

Directory of Open Access Journals (Sweden)

Bo You

2015-01-01

Full Text Available In order to predict pressing quality of precision press-fit assembly, press-fit curves and maximum press-mounting force of press-fit assemblies were investigated by finite element analysis (FEA. The analysis was based on a 3D Solidworks model using the real dimensions of the microparts and the subsequent FEA model that was built using ANSYS Workbench. The press-fit process could thus be simulated on the basis of static structure analysis. To verify the FEA results, experiments were carried out using a press-mounting apparatus. The results show that the press-fit curves obtained by FEA agree closely with the curves obtained using the experimental method. In addition, the maximum press-mounting force calculated by FEA agrees with that obtained by the experimental method, with the maximum deviation being 4.6%, a value that can be tolerated. The comparison shows that the press-fit curve and max press-mounting force calculated by FEA can be used for predicting the pressing quality during precision press-fit assembly.

A novel Fe–Cr–Nb matrix composite containing the TiB_2 neutron absorber synthesized by mechanical alloying and final hot isostatic pressing (HIP) in the Ti-tubing

International Nuclear Information System (INIS)

Litwa, Przemysław; Perkowski, Krzysztof; Zasada, Dariusz; Kobus, Izabela; Konopka, Gustaw; Czujko, Tomasz; Varin, Robert A.

2016-01-01

The Fe–Cr–Ti-Nb elemental powders were mechanically alloyed/ball milled with TiB_2 and a small quantity of Y_2O_3 ceramic to synthesize a novel Fe-based alloy-ceramic powder composite that could be processed by hot isostatic pressing (HIP) for a perceived potential application as a neutron absorber in nuclear reactors. After ball milling for the 30–80 h duration relatively uniform powders with micrometric sizes were produced. With increasing milling time a fraction of TiB_2 particles became covered with the much softer Fe-based alloy which resulted in the formation of a characteristic “core-mantel” structure. For the final HIP-ing process the mechanically alloyed powders were initially uniaxially pressed into rod-shaped compacts and then cold isostatically pressed (CIP-ed). Subsequently, the rod-shaped compacts were placed in the Ti-tubing and subjected to hot isostatic pressing (HIP) at 1150 °C/200 MPa pressure. The HIP-ing process resulted in the formation of the near-Ti and intermediate diffusional layers in the microstructure of HIP-ed samples which formed in accord with the Fe-Ti binary phase diagram. Those layers contain the phases such as α-Ti (HCP), the FeTi intermetallic and their hypo-eutectoid mixtures. In addition, needle-like particles were formed in both layers in accord with the Ti-B binary phase diagram. Nanohardness testing, using a Berkovich type diamond tip, shows that the nanohardness in the intermediate layer areas, corresponding to the composition of the hypo-eutectoid mixture of Ti-FeTi, equals 980.0 (±27.1) HV and correspondingly 1176.9 (±47.6) HV for the FeTi phase. The nanohardness in the sample's center in the areas with the fine mixture of Fe-based alloy and small TiB_2 particles equals 1048.3 (±201.8) HV. The average microhardness of samples HIP-ed from powders milled for 30 and 80 h is 588 HV and 733 HV, respectively. - Highlights: • A Fe–Cr–Nb-based composite with TiB_2 neutron absorbing ceramic was mechanically

Effects of long-time elevated temperature exposures on hot-isostatically-pressed power-metallurgy Udimet 700 alloys with reduced cobalt contents

Science.gov (United States)

Hart, F. H.

1984-01-01

Because almost the entire U.S. consumption of cobalt depends on imports, this metal has been designated "strategic'. The role and effectiveness of cobalt is being evaluated in commercial nickel-base superalloys. Udiment 700 type alloys in which the cobalt content was reduced from the normal 17% down to 12.7%, 8.5%, 4.3%, and 0% were prepared by standard powder metallurgy techniques and hot isostatically pressed into billets. Mechanical testing and microstructural investigations were performed. The mechanical properties of alloys with reduced cobalt contents which were heat-treated identically were equal or better than those of the standard alloy, except that creep rates tended to increase as cobalt was reduced. The effects of long time exposures at 760 C on mechanical properties and at 760 C and 845 C on microstructures were determined. Decreased tensile properties and shorter rupture lives with increased creep rates were observed in alloy modifications. The exposures caused gamma prime particle coarsening and formation of sigma phase in the alloys with higher cobalt contents. Exposure at 845 C also reduced the amount of MC carbides.

Forming of AHSS using Servo-Presses

Science.gov (United States)

Groseclose, Adam Richard

Stamping of Advanced High Strength Steel (AHSS) alloys poses several challenges due to the material's higher strength and low formability compared to conventional steels and other problems such as (a) inconsistency of incoming material properties, (b) ductile fracture during forming, (c) higher contact pressure and temperature rise during forming, (d) higher die wear leading to reduced tool life, (e) higher forming load/press capacity, and (f) large springback leading to dimensional inaccuracy in the formed part. [Palaniswamy et. al., 2007]. The use of AHSS has been increasing steadily in automotive stamping. New AHSS alloys (TRIP, TWIP) may replace some of the Hot Stamping applications. Stamping of AHSS alloys, especially higher strength materials, 780 MPa and higher, present new challenges in obtaining good part definition (corner and fillet radii), formability (fracture and resulting scrap) and in reducing springback. Servo-drive presses, having the capability to have infinitely variable and adjustable ram speed and dwell at BDC, offer a potential improvement in quality, part definition, and springback reduction especially when the infinitely adjustable slide motion is used in combination with a CNC hydraulic cushion. Thus, it is desirable to establish a scientific/engineering basis for improving the stamping conditions in forming AHSS using a servo-drive press.

Sintering of ZrC by hot isostatic pressing (HIP) and spark plasma sintering (SPS). Effect of impurities

International Nuclear Information System (INIS)

Allemand, Alexandre; Le Flem - Dormeval, Marion; Guillard, Francois

2005-01-01

Carbides are generally used as structural materials for high temperature applications. Particularly, ZrC because of low activation, neutronic transparency, cubic structure (isotropic behaviour) and good thermal conductivity, is one of the candidates under consideration for structural materials in the core of new high temperature nuclear reactors (Generation IV). Just a few studies about densification of monolithic ZrC exist. They mainly involve natural sintering or hot pressing at high temperature (until 2700 deg. C). Unfortunately those processes induce grain growth and do not lead to fully densified ZrC. The aim of this study is to compare the characteristics and the properties of ZrC sintered by HIP and by SPS. Fully dense ZrC can be reached either by HIP or by SPS, grain size being more or less controlled. Microstructural observations and mechanical testing of several ZrC grades shows that powder impurities play an important role in the quality of the grain boundaries and consequently in the mechanical properties. In particular, the porosity falls from 17% to 3 % just by reducing the free carbon content in starting ZrC powder. The densification process of dense monolithic ZrC was improved by combining a HIP at 1600 deg. C (titanium canning) followed by a post-HIP at 1900 deg. C (no canning required). Four-point bending tests are in progress to confirm the improvement of fracture strength. (authors)

The influence of process parameters and additives on the densification, creep properties and strength of hot pressed silicon nitride

International Nuclear Information System (INIS)

Becker, R.

1979-03-01

One method of production of Si 3 N 4 parts is the hot pressing of powder compacts. According to the current technological know how, a liquid phase building additive (e.g. MgO) is essential for the complete densification of Si 3 N 4 . In this work it has been shown, how dense Si 3 N 4 may be produced without the conventional additives. The SiO 2 -coating of Si 3 N 4 particles here results in the liquid phase formation. On the basis of the above concept, the effect of MgO, Mg 3 N 2 , Al 2 O 3 and A1N-additions to a pure Si 3 N 4 powder have been studied in detail and the resulting material properties: densification, creep and high temperature strengths have been determined. Based on the results, it may be concluded, that HPSN is a dispersion of crystalline Si 3 N 4 in an amorphous matrix (glass content between 4-10 vol%). Depending on the amount and composition of the boundary phase (silicate glass) widely variing material properties may be obtained. (orig./GSCH) [de

Microstructure and properties of diffusion bonded Ti-6Al-4V parts using brazing-assisted hot isostatic pressing

International Nuclear Information System (INIS)

Wu, Z.; Mei, J.; Voice, W.; Beech, Steve; Wu, X.

2011-01-01

Highlights: → A low cost method of diffusion bonding has been developed for complex-shaped components of Ti6Al4V. → Vacuum brazing has been used to seal the periphery to allow encapsulation-free HIPping. → The tensile properties of the bonds are comparable with those of the bulk material, but the fatigue life was slightly reduced. - Abstract: Ti-6Al-4V couples have been diffusion bonded by hot isostatic pressing (HIPping) after vacuum brazing was used to seal the periphery of the bonding samples so that no encapsulation was required during HIPping. Analytical scanning electron microscopy was used to assess the microstructure of the HIPped interface and tensile and fatigue properties of bonded samples were compared with those of the bulk starting material. The tensile properties of the bonds were shown to be comparable with those of the bulk material, but the fatigue life was slightly downgraded. The fatigue fractures were initiated by inclusions on the bonding interface, caused by contamination before bonding, but the fatigue cracks did not propagate along the bonding interface indicating a strong bond. It is concluded that this technique of vacuum brazing plus HIPping could be used for encapsulation-free HIPping to produce complex-shaped components.

Chemical composition and oxidative stability of jussara (Euterpe edulis M.) oil extracted by cold and hot mechanical pressing; Composición química y estabilidad oxidativa del aceite de jussara (Euterpe edulis M.) extraído mediante prensado mecánico en frío y en caliente

Energy Technology Data Exchange (ETDEWEB)

Da Cunha, A.L.A.; Freitas, S.P.; Godoy, R.L.O.; Cabral, L.M.C.; Tonon, R.V.

2017-07-01

The aim of this work was to evaluate the effect of mechanical pressing on jussara oil yield, oxidative stability and carotenoid profile with or without heat application. Firstly, jussara pulp was centrifuged for juice extraction, and the resulting cake was dried until reaching 10% moisture content. Then, oil extraction was performed in an expeller press at 25 ºC (cold pressing) and at 50 ºC (hot pressing). The process performance was evaluated by the oil yield, and the crude jussara oil was characterized for fatty acid composition, acid value, carotenoid profile and oxidative stability. Jussara oil contained 74% unsaturated fatty acids, mainly oleic and linoleic acids (48% and 24%, respectively). The oil yield was almost twice as high for the hot process as compared to the cold one. Additionally, hot pressing resulted in 25% higher total carotenoid content as compared to cold pressing, with β-carotene as the most abundant one. Hot and cold pressing showed no difference in oil oxidative stability and fatty acid composition. [Spanish] El objetivo de este estudio fue evaluar el efecto del calor sobre el rendimiento del aceite, la estabilidad oxidativa y el perfil de carotenoides del aceite de Jussara extraído por prensado mecánico. En primer lugar, se centrifugó la pulpa de jussara para la extracción del zumo, y la torta resultante se secó para alcanzar el contenido de humedad de 10%. Posteriormente, la extracción del aceite se realizó en una prensa a 25 °C (prensado en frío) y a 50 °C (prensado en caliente). El desarrollo del proceso fue evaluado mediante el rendimiento de aceite y en bruto y éste se caracterizó mediante la composición en ácidos grasos, índice de acidez, perfil de carotenoides y la estabilidad oxidativa. El aceite de jussara presentó un 74% de ácidos grasos insaturados, principalmente ácidos oleico y linoleico (48% y 24%, respectivamente). El rendimiento del aceite para el proceso en caliente fue casi el doble, en comparaci

Pressing of three-layer, dry-formed MDF with binderless hardboard faces

Science.gov (United States)

Otto Suchsland; George E. Woodson; Charles W. McMillin

1986-01-01

Severely cooked Masonite pulp was used as face material in three-layer experimental medium-density fiberboard (MDF). The core layer consisted of conventional MDF furnish with resin binder added. The faces were formed absolutely dry without additives of any kind. The three-layer mat was hot-pressed to overall densities ranging from 44 to 56 pcf. The faces had hardboard-...

The Study on Weldability of Boron Steel and Hot-Stamped Steel by Using Laser Heat Source (Ⅲ) - Comparison on Laser Weldability of Boron Steel and Hot -Stamped Steel-

Energy Technology Data Exchange (ETDEWEB)

Choi, So Young; Kim, Jong Do [Korea Maritime and Ocean University, Busan (Korea, Republic of); Kim, Jong Su [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

2015-01-15

This study was conducted to compare the laser weldability of boron steel and hot-stamped steel. In general, boron steel is used in the hot-stamping process. Hot-stamping is a method for simultaneously forming and cooling boron steel in a press die after heating it to the austenitizing temperature. Hot-stamped steel has a strength of 1500 MPa or more. Thus, in this study, the laser weldability of boron steel and that of hot-stamped steel were investigated and compared. A continuous wave disk laser was used to produce butt and lap joints. In the butt welding, the critical cooling speed at which full penetration was obtained in the hot-stamped steel was lower than that of boron steel. In the lap welding, the joint widths were similar regardless of the welding speed when full penetration was obtained.

The Study on Weldability of Boron Steel and Hot-Stamped Steel by Using Laser Heat Source (Ⅲ) - Comparison on Laser Weldability of Boron Steel and Hot -Stamped Steel-

International Nuclear Information System (INIS)

Choi, So Young; Kim, Jong Do; Kim, Jong Su

2015-01-01

This study was conducted to compare the laser weldability of boron steel and hot-stamped steel. In general, boron steel is used in the hot-stamping process. Hot-stamping is a method for simultaneously forming and cooling boron steel in a press die after heating it to the austenitizing temperature. Hot-stamped steel has a strength of 1500 MPa or more. Thus, in this study, the laser weldability of boron steel and that of hot-stamped steel were investigated and compared. A continuous wave disk laser was used to produce butt and lap joints. In the butt welding, the critical cooling speed at which full penetration was obtained in the hot-stamped steel was lower than that of boron steel. In the lap welding, the joint widths were similar regardless of the welding speed when full penetration was obtained

Comparison of Ti(C,N)-based cermets processed by hot-pressing sintering and conventional pressureless sintering

International Nuclear Information System (INIS)

Xu, Qingzhong; Ai, Xing; Zhao, Jun; Qin, Weizhen; Wang, Yintao; Gong, Feng

2015-01-01

Highlights: • The HP sintered Ti(C,N)-based cermets exhibit high hardness with fine grain size. • The PLS sintered cermets possess high mechanical properties with low porosity. • The applied pressure can rearrange particles and contribute to grain refinement. • The heating rate can greatly affect the solid and liquid phase sintering of cermets. - Abstract: A suitable sintering method is important to obtain the Ti(C,N)-based cermets with superior properties. In this paper, Ti(C,N)-based cermets were fabricated by hot-pressing sintering (HP) and conventional pressureless sintering (PLS) technology, respectively, to investigate the influence of different sintering methods on the microstructure and mechanical properties of cermets materials. The microstructure, fracture morphology, indention cracks and phase composition were observed and detected using scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The transverse rupture strength (TRS), Vickers hardness (HV) and fracture toughness (K IC ) were also measured. The results reveal that all of the Ti(C,N)-based cermets exhibit core–rim microstructures with black cores, white cores and grey rims embedded into metal binder phases. The grain size of the samples fabricated by HP is much finer and the structure is more compact than those fabricated by PLS, while there exist pores in the HP sintered samples. The sintering process has no influence on the phase composition of cermets, but affects the phase content and crystallinity. The samples fabricated by PLS present higher transverse rupture strength, fracture toughness and density than samples fabricated by HP. However, the HP sintered samples possess a higher hardness

A novel Fe–Cr–Nb matrix composite containing the TiB{sub 2} neutron absorber synthesized by mechanical alloying and final hot isostatic pressing (HIP) in the Ti-tubing

Energy Technology Data Exchange (ETDEWEB)

Litwa, Przemysław [Department of Advanced Materials and Technologies, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland); Perkowski, Krzysztof [Department of Nanotechnology, Institute of Ceramics and Building Materials, Postępu 9, 02-676 Warsaw (Poland); Zasada, Dariusz [Department of Advanced Materials and Technologies, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland); Kobus, Izabela; Konopka, Gustaw [Department of Nanotechnology, Institute of Ceramics and Building Materials, Postępu 9, 02-676 Warsaw (Poland); Czujko, Tomasz [Department of Advanced Materials and Technologies, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland); Varin, Robert A., E-mail: robert.varin@uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave., Waterloo, ON N2L 3G1 (Canada)

2016-07-25

The Fe–Cr–Ti-Nb elemental powders were mechanically alloyed/ball milled with TiB{sub 2} and a small quantity of Y{sub 2}O{sub 3} ceramic to synthesize a novel Fe-based alloy-ceramic powder composite that could be processed by hot isostatic pressing (HIP) for a perceived potential application as a neutron absorber in nuclear reactors. After ball milling for the 30–80 h duration relatively uniform powders with micrometric sizes were produced. With increasing milling time a fraction of TiB{sub 2} particles became covered with the much softer Fe-based alloy which resulted in the formation of a characteristic “core-mantel” structure. For the final HIP-ing process the mechanically alloyed powders were initially uniaxially pressed into rod-shaped compacts and then cold isostatically pressed (CIP-ed). Subsequently, the rod-shaped compacts were placed in the Ti-tubing and subjected to hot isostatic pressing (HIP) at 1150 °C/200 MPa pressure. The HIP-ing process resulted in the formation of the near-Ti and intermediate diffusional layers in the microstructure of HIP-ed samples which formed in accord with the Fe-Ti binary phase diagram. Those layers contain the phases such as α-Ti (HCP), the FeTi intermetallic and their hypo-eutectoid mixtures. In addition, needle-like particles were formed in both layers in accord with the Ti-B binary phase diagram. Nanohardness testing, using a Berkovich type diamond tip, shows that the nanohardness in the intermediate layer areas, corresponding to the composition of the hypo-eutectoid mixture of Ti-FeTi, equals 980.0 (±27.1) HV and correspondingly 1176.9 (±47.6) HV for the FeTi phase. The nanohardness in the sample's center in the areas with the fine mixture of Fe-based alloy and small TiB{sub 2} particles equals 1048.3 (±201.8) HV. The average microhardness of samples HIP-ed from powders milled for 30 and 80 h is 588 HV and 733 HV, respectively. - Highlights: • A Fe–Cr–Nb-based composite with TiB{sub 2} neutron

Effects of Fe fine powders doping on hot deformed NdFeB magnets

International Nuclear Information System (INIS)

Lin, Min; Wang, Huijie; Zheng, Jingwu; Yan, Aru

2015-01-01

The composite NdFeB magnets with blending melt-spun flakes and Fe fine powders were prepared by the hot-pressed and hot-deformed route. Characterizations of the hot-deformed NdFeB magnets affected by the doped Fe powders were tested. The doped Fe powders decrease the hot-deformed pressure when the strain is between 15 and 50%. XRD patterns show that the doped Fe powders have little influence on the c-axis alignment of hot-deformed NdFeB magnets in the press direction. The B r and the (BH) max get improved when the doped Fe powders are less than 3 wt%. The doped Fe of hot-deformed NdFeB magnets exists in the elongated state and the spherical state surrounded by the Nd-rich phase. With the Fe fraction increasing, the potential of magnet moves to the positive direction and the diameter of the Nyquist arc becomes larger, which indicate that the corrosion resistance improved effectively. The bending strength was enhanced by the elongated α-Fe phase embedded in the matrix 2:14:1 phase. - Highlights: • The doped Fe powders have little influence on the c-axis alignment of magnets. • The elongated Fe powders are more than the spherical Fe powders in the magnets. • The corrosion resistance is improved effectively with the increasing Fe fraction. • The bending strength is enhanced by the elongated α-Fe phase embedded in the matrix

Effects of Fe fine powders doping on hot deformed NdFeB magnets

Energy Technology Data Exchange (ETDEWEB)

Lin, Min, E-mail: linm@nimte.ac.cn [Ningbo Institute of Material Technology & Engineering Chinese Academy of Science, Ningbo 315201 (China); Wang, Huijie [Ningbo Jinji Strong Magnetic Material Company, Ningbo 315041 (China); Zheng, Jingwu [Zhejiang University of Technology, Hangzhou 310014 (China); Yan, Aru [Ningbo Institute of Material Technology & Engineering Chinese Academy of Science, Ningbo 315201 (China)

2015-04-01

The composite NdFeB magnets with blending melt-spun flakes and Fe fine powders were prepared by the hot-pressed and hot-deformed route. Characterizations of the hot-deformed NdFeB magnets affected by the doped Fe powders were tested. The doped Fe powders decrease the hot-deformed pressure when the strain is between 15 and 50%. XRD patterns show that the doped Fe powders have little influence on the c-axis alignment of hot-deformed NdFeB magnets in the press direction. The B{sub r} and the (BH){sub max} get improved when the doped Fe powders are less than 3 wt%. The doped Fe of hot-deformed NdFeB magnets exists in the elongated state and the spherical state surrounded by the Nd-rich phase. With the Fe fraction increasing, the potential of magnet moves to the positive direction and the diameter of the Nyquist arc becomes larger, which indicate that the corrosion resistance improved effectively. The bending strength was enhanced by the elongated α-Fe phase embedded in the matrix 2:14:1 phase. - Highlights: • The doped Fe powders have little influence on the c-axis alignment of magnets. • The elongated Fe powders are more than the spherical Fe powders in the magnets. • The corrosion resistance is improved effectively with the increasing Fe fraction. • The bending strength is enhanced by the elongated α-Fe phase embedded in the matrix.

Zinc coated sheet steel for press hardening

Science.gov (United States)

Ghanbari, Zahra N.

Galvanized steels are of interest to enhance corrosion resistance of press-hardened steels, but concerns related to liquid metal embrittlement have been raised. The objective of this study was to assess the soak time and temperature conditions relevant to the hot-stamping process during which Zn penetration did or did not occur in galvanized 22MnB5 press-hardening steel. A GleebleRTM 3500 was used to heat treat samples using hold times and temperatures similar to those used in industrial hot-stamping. Deformation at both elevated temperature and room temperature were conducted to assess the coating and substrate behavior related to forming (at high temperature) and service (at room temperature). The extent of alloying between the coating and substrate was assessed on undeformed samples heat treated under similar conditions to the deformed samples. The coating transitioned from an α + Gamma1 composition to an α (bcc Fe-Zn) phase with increased soak time. This transition likely corresponded to a decrease in availability of Zn-rich liquid in the coating during elevated temperature deformation. Penetration of Zn into the substrate sheet in the undeformed condition was not observed for any of the processing conditions examined. The number and depth of cracks in the coating and substrate steel was also measured in the hot-ductility samples. The number of cracks appeared to increase, while the depth of cracks appeared to decrease, with increasing soak time and increasing soak temperature. The crack depth appeared to be minimized in the sample soaked at the highest soak temperature (900 °C) for intermediate and extended soak times (300 s or 600 s). Zn penetration into the substrate steel was observed in the hot-ductility samples soaked at each hold temperature for the shortest soak time (10 s) before being deformed at elevated temperature. Reduction of area and elongation measurements showed that the coated sample soaked at the highest temperature and longest soak time

Nd-Fe-B-Cu hot deformation processing: a comparison of deformation modes, microstructural development and magnetic properties

International Nuclear Information System (INIS)

Ferrante, M.; Sinka, V.; Assis, O.B.G.; Oliveira, I. de; Freitas, E. de

1996-01-01

Due to its relative simplicity and low cost the hot deformation of Nd-Fe-B ingots is rapidly reaching the status of a valid alternative to sintering. Among the possible deformation modes, pressing, rolling and forging are perhaps the most successful. This paper describes the research programme undertaken so far, by discussing the relationship between deformation mode, microstructure and magnetic properties of magnets produced by hot deformation mode, microstructure and magnetic properties of magnets produced by hot deformation of a number of Nd-fe-B-Cu alloys. Microstructural observation showed that both pressed and forged samples are characterized by a heterogeneous microstructure and from magnetic measurements it was concluded that magnetic properties differ when taken in the center or in the periphery of the sample. On the other hand roller magnets were homogeneous both in terms of microstructure and magnetic properties, and interpretations of the mechanisms of texture development and of microstructural development of hot deformed magnets is put forward. (author)

Influence of Fiber Content on Mechanical and Morphological Properties of Woven Kenaf Reinforced PVB Film Produced Using a Hot Press Technique

Directory of Open Access Journals (Sweden)

Suhad D. Salman

2016-01-01

Full Text Available This work addresses the results of experimental investigation carried out on mechanical and morphological properties of plain woven kenaf fiber reinforced PVB film which was prepared by hot press technique. The composites were prepared with various fiber contents: 0%, 10%, 20%, 30%, 40%, 50%, and 60% (by weight, with the processing parameters 165°C, 20 min, and at a pressure of 8 MPa applied on the material. Tensile, flexural, and Charpy impact properties were studied as well as morphological properties of impact fracture surface. With the increase in kenaf fibers content up to 40%, the PVB composites have shown lower tensile and flexural strength accompanied with reduction in the ultimate strain of the composite. The results showed that impact properties were affected in markedly different ways by using various kenaf contents and decrease with the increase in kenaf fiber content up to 40%; however, high impact strength was observed even with 40% kenaf fiber content. Furthermore, scanning electron microscopy for impact samples was utilised to demonstrate the different failures in the fracture surfaces for various kenaf fibers contents.

Vacuum hot-pressed beryllium and TiC dispersion strengthened tungsten alloy developments for ITER and future fusion reactors

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiang, E-mail: xliu@swip.ac.cn [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan (China); Chen, Jiming; Lian, Youyun; Wu, Jihong; Xu, Zengyu; Zhang, Nianman; Wang, Quanming; Duan, Xuro [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, Sichuan (China); Wang, Zhanhong; Zhong, Jinming [Northwest Rare Metal Material Research Institute, CNMC, Ningxia Orient Group Co. Ltd.,No.119 Yejin Road, Shizuishan City, Ningxia,753000 (China)

2013-11-15

Beryllium and tungsten have been selected as the plasma facing materials of the ITER first wall (FW) and divertor chamber, respectively. China, as a participant in ITER, will share the manufacturing tasks of ITER first-wall mockups with the European Union and Russia. Therefore ITER-grade beryllium has been developed in China and a kind of vacuum hot-pressed (VHP) beryllium, CN-G01, was characterized for both physical, and thermo-mechanical properties and high heat flux performance, which indicated an equivalent performance to U.S. grade S-65C beryllium, a reference grade beryllium of ITER. Consequently CN-G01 beryllium has been accepted as the armor material of ITER-FW blankets. In addition, a modification of tungsten by TiC dispersion strengthening was investigated and a W–TiC alloy with TiC content of 0.1 wt.% has been developed. Both surface hardness and recrystallization measurements indicate its re-crystallization temperature approximately at 1773 K. Deuterium retention and thermal desorption behaviors of pure tungsten and the TiC alloy were also measured by deuterium ion irradiation of 1.7 keV energy to the fluence of 0.5–5 × 10{sup 18} D/cm{sup 2}; a main desorption peak at around 573 K was found and no significant difference was observed between pure tungsten and the tungsten alloy. Further characterization of the tungsten alloy is in progress.

Process design of press hardening with gradient material property influence

International Nuclear Information System (INIS)

Neugebauer, R.; Schieck, F.; Rautenstrauch, A.

2011-01-01

Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties.

Enhancement in the microstructure and neutron shielding efficiency of sandwich type of 6061Al–B4C composite material via hot isostatic pressing

International Nuclear Information System (INIS)

Park, Jin-Ju; Hong, Sung-Mo; Lee, Min-Ku; Rhee, Chang-Kyu; Rhee, Won-Hyuk

2015-01-01

Highlights: • 6061Al–B 4 C neutron shielding composites are fabricated by sintering and HIP. • HIP process improves the wettability of B 4 C particles into 6061Al matrix. • Neutron attenuation performance can be enhanced by application of HIP process. - Abstract: Sandwich type of 6061Al–B 4 C composite plates, which are used as a thermal neutron absorber for spent nuclear fuel pool storage rack, were fabricated using two different consolidation ways as sintering and hot isostatic pressing (HIP) processes and their thermal neutron shielding efficiency was investigated as a function of B 4 C concentration ranging from 0 to 40 wt.%. For this purpose, two respective inner core compaction parts of sintered and HIPped neutron absorbing composite materials were first produced and then cladded them between two outer plates by HIP process. The application of HIP process provided not only a lead of excellent interfacial adhesion due to the improved wettability but also an enhancement of thermal neutron shielding efficiency owing to the more uniform dispersion of B 4 C particles

Fabrication of a Nano-ZnO/Polyethylene/Wood-Fiber Composite with Enhanced Microwave Absorption and Photocatalytic Activity via a Facile Hot-Press Method

Directory of Open Access Journals (Sweden)

Baokang Dang

2017-11-01

Full Text Available A polyethylene/wood-fiber composite loaded with nano-ZnO was prepared by a facile hot-press method and was used for the photocatalytic degradation of organic compounds as well as for microwave absorption. ZnO nanoparticles with an average size of 29 nm and polyethylene (PE powders were dispersed on the wood fibers’ surface through a viscous cationic polyacrylamide (CPAM solution. The reflection loss (RL value of the resulting composite was −21 dB, with a thickness of 3.5 mm in the frequency of 17.17 GHz. The PE/ZnO/wood-fiber (PZW composite exhibited superior photocatalytic activity (84% methyl orange degradation within 300 min under UV light irradiation. ZnO nanoparticels (NPs increased the storage modulus of the PZW composite, and the damping factor was transferred to the higher temperature region. The PZW composite exhibited the maximum flexural strength of 58 MPa and a modulus of elasticity (MOE of 9625 MPa. Meanwhile, it also displayed dimensional stability (thickness swelling value of 9%.

Laser Welding of Coated Press-hardened Steel 22MnB5

Science.gov (United States)

Siltanen, Jukka; Minkkinen, Ari; Järn, Sanna

The press-hardening process is widely used for steels that are used in the automotive industry. Using ultra-high-strength steels enables car manufacturers to build lighter, stronger, and safer vehicles at a reduced cost and generating lower CO2 emissions. In the study, laser welding properties of the coated hot stamped steel 22BMn5 were studied. A constant 900 °C temperature was used to heat the steel plates, and two different furnace times were used in the press-hardening, being 300 and 740 seconds. Some of the plates were shot blasted to see the influence of the partly removed oxide layer on the laser welding and quality. The welding set-up, welding, and testing of the weld specimens complied with the automotive testing code SEP 1220.

Development of manufacturing technology of radial plate in superconducting coil for fusion reactor by diffusion bonding by Hot Isostatic Pressing (HIP)

International Nuclear Information System (INIS)

Takano, Katsutoshi; Koizumi, Norikiyo; Masuo, Hiroshi; Natsume, Yoshihisa

2014-01-01

The radial plates (RPs), which is used in Toroidal field (TF) coil in ITER, are quite large, such as 13 m tall and 9 m wide, but thin, such as 10 cm thick, and are made of stainless steel. Even though they are very large structures, they require very high manufacturing tolerances and high mechanical strength at 4 K. The similar requirements will be required in the next generation fusion reactor. Therefore, the authors intend to develop efficient manufacturing methods in parallel with ITER TF coil RP manufacture. The authors therefore performed trial manufacture of the RP segments using a diffusion bonding method, namely Hot Isostatic Pressing (HIP). As a result of trials, it was clarified that even when HIPping is applied, the mechanical characteristic of base metal is not deteriorated. The machining period can be reduced by about 1/3 compared with the traditional manufacturing method. On the other hand, mechanical strength at 4 K is degraded due to weak bonding, that is no grain growth through joint, by HIPping. However, additional test indicates promising possibility of much better joint by higher temperature and joint surface treated HIPpings. These results justified that RP segment manufacturing is not only possible, but it is a technically valid manufacturing method that satisfies all requirements. (author)

Comparison of structure, morphology, and leach characteristics of multi-phase ceramics produced via melt processing and hot isostatic pressing

Science.gov (United States)

Dandeneau, Christopher S.; Hong, Tao; Brinkman, Kyle S.; Vance, Eric R.; Amoroso, Jake W.

2018-04-01

Melt processing of multi-phase ceramic waste forms offers potential advantages over traditional solid-state synthesis methods given both the prevalence of melters currently in use and the ability to reduce the possibility of airborne radionuclide contamination. In this work, multi-phase ceramics with a targeted hollandite composition of Ba1.0Cs0.3Cr1.0Al0.3Fe1.0Ti5.7O16 were fabricated by melt processing at 1675 °C and hot isostatic pressing (HIP) at 1250 and 1300 °C. X-ray diffraction analysis (XRD) confirmed hollandite as the major phase in all specimens. Zirconolite/pyrochlore peaks and weaker perovskite reflections were observed after melt processing, while HIP samples displayed prominent perovskite peaks and low-intensity zirconolite reflections. Melt processing produced specimens with large (>50 μm) well-defined hollandite grains, while HIP yielded samples with a more fine-grained morphology. Elemental analysis showed "islands" rich in Cs and Ti across the surface of the 1300 °C HIP sample, suggesting partial melting and partitioning of Cs into multiple phases. Photoemission data revealed multiple Cs 3d spin-orbit pairs for the HIP samples, with the lower binding energy doublets likely corresponding to Cs located in more leachable phases. Among all specimens examined, the melt-processed sample exhibited the lowest fractional release rates for Rb and Cs. However, the retention of Sr and Mo was greater in the HIP specimens.

Sintering of Si C by hot-pressing with addition of Al2O3 and concentrate of rare earths

International Nuclear Information System (INIS)

Hwang, M.K.; Silva, C.R.M.

2004-01-01

Silicon carbide (SiC) has essentially covalent bonds (∼88%). The high covalency bond is responsible for the good mechanical properties, although it induces a low self diffusion coefficient, making densification more difficult. For a successful densification is necessary to apply pressure on the samples, and/or the addition of sintering additives, which improves the densification. In this SiC samples with alumina (Al2O3) and concentrate of rare earth (CRE) addition were sintered by hot pressing in argon atmospheric at 20 MPa of pressure, heating rate of 20 deg C/min up to 1800 deg C and a dwell time of 1 h. Initially the CRE was calcined at 1000 deg C during 1 h. After that, three mixtures were prepared with distinct concentrations in high energy mill and the samples were sintered. The aim of this work is to improve SiC densification by the liquid phase formation during sintering owing to the additives reactions between itself. The pressure intensify the driving force for densification, taking the liquid phase to drain easier through the grain boundaries, making possible best accommodation and rearrangement of the grains. The application of the pressure on the samples during sintering contributes to improve densification and becomes possible sintering in lower temperature than conventional one. The phases of the sintered samples were analyzed by X-ray diffraction and the morphology were verified by scanning electron microscopy. (author)

Texturing of superconducting Bi-Pb-Sr-Ca-Cu-O ceramics by combining the effect of a magnetic field and hot pressing in one direction; Texturation des ceramiques supraconductrices Bi-Pb-Sr-Ca-Cu-O par combinaison des effets du champ magnetique et de la contrainte uniaxiale a haute temperature

Energy Technology Data Exchange (ETDEWEB)

Noudem, J G

1995-10-27

Superconducting Bi-(Pb)-Sr-Ca-Cu-O (Bi:2223) ceramics have a weak 77 K transport critical current density (Jc) due to porosity and the presence of misaligned platelets. In order to obtain higher critical current densities in these materials, it is necessary to increase their density and induce a preferential crystallographic orientation. We have developed a texturing process using solidification in a magnetic field combined with hot pressing. The experimental set-up provides a uniaxial pressure of 60 MPa and temperature up to 1100 deg C in a magnetic field of 8 T. Magnetic melt texturing (MMT) proved to be very effective in producing bulk oriented samples of polycrystalline Bi:2223 (crystallite c-axis oriented parallel to the field direction). These samples have Jc values of up to 1450 A/cm{sup 2} and a density of 5.1 g/cm{sup 3}. The texturing by hot pressing (HP) gives homogeneous, dense ({approx} 6 g/cm{sup 3}; 95 % of the theoretical limit) ceramics with a Jc of 2500 A/cm{sup 2}. Tapes of Ag/Bi:2223 provided by Alcatel Alsthom were also successful textured using HP. Finally we have demonstrated that the combination of solidification in a magnetic field with hot pressing (MMHPT) improves both the texture and density of the samples. Moreover the samples are very homogeneous and mechanically resistant. The 77 K transport critical current densities have values up to 3800 A/cm{sup 2} and 1100 A/cm{sup 2} along the (ab) and c-axis respectively. We have demonstrated that these samples are of potential use a current limiters. (author) 146 refs.

Effect of hot extrusion, other constituents, and temperature on the strength and fracture of polycrystalline MgO

Energy Technology Data Exchange (ETDEWEB)

Rice, R.W. (W.R. Grace and Co.-Conn, Columbia, MD (United States))

1993-12-01

Improved agreement was confirmed between the Petch intercept and single-crystal yield stresses at 22 C. Hot-extruded MgO crystal specimens stressed parallel with the resultant axial texture (1) gave the highest and least-scattered strength-grain size results at 22 C, (2) showed direct fractographic evidence of microplastic initiated fracture at 22 C and showed macroscopic yield at 1,315 and especially 1,540 C, and (3) fractured entirely via transgranular cleavage, except for intergranular failure initiation from one or a few grain boundary surfaces exposed on the subsequent fracture surface, mainly at 1,540 C. Hot-extruded, hot-pressed MgO billets gave comparable strength when fracture initiated transgranularly, but lower strength when fracture initiated from one or especially a few grain boundary surfaces exposed on the fracture. The extent and frequency of such boundary fracture increased with test temperature. While oxide additions of [<=] 5% or impurities in hot-pressed or hot-extruded MgO can make limited strength increases at larger grain sizes, those having limited solubility can limit strength at finer grain sizes, as can coarser surface finish. Overall, MgO strength is seen as a balance between flaw and microplastic controlled failure, with several parameters shifting the balance.

Ceramic containers for spent nuclear fuel. II. Reactions between TiO2 and the steel canning during hot isostatic processing

International Nuclear Information System (INIS)

Bergman, B.; Forberg, S.

1984-01-01

Rutile was selected for some practical studies of processing and properties of ceramic containers. Hot isostatic pressing at 1280 0 C has resulted in reaction zones between the TiO 2 powder and the steel canning. The phases ilmenite, pseudobrookite, rutile, and iron have been identified by x-ray diffraction and by microprobe analysis. The microstructures have been interpreted by classical metallographic methods, and some microstructures obtained by hot pressing and rapid cooling have also been examined for purposes of comparison. Some implications of the microstructures have been discussed in terms of microcracking and slow crack growth. 13 refs., 7 figs

Microstructure and Mechanical Properties of Multiphase Strengthened Al/Si/Al_2O_3/SiO_2/MWCNTs Nano composites Sintered by In Situ Vacuum Hot Pressing

International Nuclear Information System (INIS)

Li, J.; Jiang, X.; Zhu, D.; Zhu, M.; Shao, Z.; Johnson, S.; Luo, Z.

2015-01-01

Eutectic Al/Si binary alloy is technically one of the most important Al casting alloys due to its high corrosion resistance, evident shrinkage reduction, low thermal expansion coefficient, high fluidity, and good weldability. In this work, multi phased Al/Si matrix nano composites reinforced with Al_2O_3 and multi walled carbon nano tubes (MWCNTs) have been sintered by an in situ vacuum hot-pressing method. The alumina Al_2O_3 nanoparticles were introduced by an in situ reaction of Al with SiO_2. Microstructure and mechanical properties of the sintered Al/Si/Al_2O_3/SiO_2/MWCNTs nano composites with different alumina contents were investigated. The mechanical properties were determined by micro-Vickers hardness and compressive and shear strength tests. The results demonstrated that in situ alumina and MWCNTs had impacts on microstructure and mechanical properties of the nano composites. Based on the mechanical properties and microstructure of the nano composites, strengthening and fracture mechanisms by multiple reinforcements were analyzed

Impact properties of reduced activation ferritic/martensitic steel, F82H jointed by hot isostatic pressing

Energy Technology Data Exchange (ETDEWEB)

Ogiwara, H.; Tanigawa, H. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Hirose, T. [Blanket Engineering Group, Japan Atomic Energy Agency, Naka, Ibaraki (Japan); Enoeda, M. [Naka Fusion Research Establishment, J.A.E.R.I., Japan Atomic Energy Research Institute, Ibaraki-ken (Japan); Kohyama, A. [Kyoto Univ., lnstitute of Advanced Energy (Japan)

2007-07-01

Full text of publication follows: Reduced-activation ferritic/martensitic steels are the leading candidate structural material for the blanket system of fusion reactors. The important issue at the current stage is the finalization of a detailed manufacturing specification for ITER test blanket module. Hot isostatic pressing (HIP) process is one of the most important methods to fabricate the first wall with cooling channels. The objective of this paper is to optimize HIP condition to obtain the excellent joints mechanical properties. The materials used were F82H steels. The joint was produced by solid state HIP method. Before HIP treatments, specimens were heated in vacuum condition to out-gas. This treatment was conducted to decrease oxidation on the surfaces. HIP treatments were carried out for 2 h at 1100 deg. C - 140 MPa. The specimens were normalized at 960 deg. C for 0.5 h and tempered at 750 deg. C for 1.5 h. The bonding interface was characterized by scanning electron microscopy. Charpy impact tests and tensile tests were conducted to evaluate the mechanical properties of the HIP joint. Impact tests revealed that there were no significant differences in the ductile-brittle transition temperatures of HIP jointed specimens and base metal specimens, but the upper-shelf energy (USE) of the HIP joint specimens at room temperature was only about 10% of that of the base metal specimens. SEM observations of the fracture surface of HIP joint specimens revealed that a large number of oxides were formed on the HIP joint. This result indicates that oxides formed on the HIP joint are the dominant factor of the impact properties. Based on these results, the pre-HIP treatment conditions had been optimized to reduce the number of oxides, and USE of HIP joint specimens increased to about 50% of that of the base metal. The detailed analyses on the HIP joint microstructure will be reported. (authors)

Design Evolutuion of Hot Isotatic Press Cans for NTP Cermet Fuel Fabrication

Science.gov (United States)

Mireles, O. R.; Broadway, J.; Hickman, R.

2014-01-01

Nuclear Thermal Propulsion (NTP) is under consideration for potential use in deep space exploration missions due to desirable performance properties such as a high specific impulse (> 850 seconds). Tungsten (W)-60vol%UO2 cermet fuel elements are under development, with efforts emphasizing fabrication, performance testing and process optimization to meet NTP service life requirements [1]. Fuel elements incorporate design features that provide redundant protection from crack initiation, crack propagation potentially resulting in hot hydrogen (H2) reduction of UO2 kernels. Fuel erosion and fission product retention barriers include W coated UO2 fuel kernels, W clad internal flow channels and fuel element external W clad resulting in a fully encapsulated fuel element design as shown.

The evolutionary turnover of recombination hot spots contributes to speciation in mice.

Science.gov (United States)

Smagulova, Fatima; Brick, Kevin; Pu, Yongmei; Camerini-Otero, R Daniel; Petukhova, Galina V

2016-02-01

Meiotic recombination is required for the segregation of homologous chromosomes and is essential for fertility. In most mammals, the DNA double-strand breaks (DSBs) that initiate meiotic recombination are directed to a subset of genomic loci (hot spots) by sequence-specific binding of the PRDM9 protein. Rapid evolution of the DNA-binding specificity of PRDM9 and gradual erosion of PRDM9-binding sites by gene conversion will alter the recombination landscape over time. To better understand the evolutionary turnover of recombination hot spots and its consequences, we mapped DSB hot spots in four major subspecies of Mus musculus with different Prdm9 alleles and in their F1 hybrids. We found that hot spot erosion governs the preferential usage of some Prdm9 alleles over others in hybrid mice and increases sequence diversity specifically at hot spots that become active in the hybrids. As crossovers are disfavored at such hot spots, we propose that sequence divergence generated by hot spot turnover may create an impediment for recombination in hybrids, potentially leading to reduced fertility and, eventually, speciation. Published by Cold Spring Harbor Laboratory Press.

Smashing WordPress Themes Making WordPress Beautiful

CERN Document Server

Hedengren, Thord Daniel

2011-01-01

The ultimate guide to WordPress Themes - one of the hottest topics on the web today WordPress is so much more than a blogging platform, and Smashing WordPress Themes teaches readers how to make it look any way they like - from a corporate site, to a photography gallery and moreWordPress is one of the hottest tools on the web today and is used by sites including The New York Times, Rolling Stone, flickr, CNN, NASA and of course Smashing MagazineBeautiful full colour throughout - web designers expect nothing lessSmashing Magazine will fully support this book by by promoting it through their webs

Influences of hot-isostatic-pressing temperature on microstructure, tensile properties and tensile fracture mode of Inconel 718 powder compact

International Nuclear Information System (INIS)

Chang, Litao; Sun, Wenru; Cui, Yuyou; Yang, Rui

2014-01-01

Inconel 718 powders have been hot-isostatic-pressed (HIPed) at representative temperatures to investigate the variations in microstructure, tensile properties and tensile fracture mode of the powder compact. Microstructure of the powder compacts were characterized by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and so on. The results showed that the interdendritic precipitates inherited from the powders were partially retained in the powder compacts when the powders were HIPed at or below 1210 °C but were eliminated when HIPed at and above 1260 °C. The grain size uniformity of the powder compacts first increases and then decreases with increasing HIPing temperature. Prior particle boundaries (PPBs) were observed in the powder compacts HIPed at and below 1260 °C but was eliminated when HIPed at 1275 °C. The PPBs were decorated with carbide particles, the amount of the carbide particles at the PPBs decreases with increasing HIPing temperature. Most of the PPBs were pinned by the carbide particles in the compacts HIPed at 1140 °C. When the HIPing temperature was increased to 1210 °C and 1260 °C, a large number of PPBs de-pinned and moved beyond the pinning carbide particles, leading to grain growth and leaving carbide particles at the site of the original PPBs within the new grains. With increasing HIPing temperature, the 0.2% yield strength of the powder compacts at 650 °C decreases, the tensile elongation increases, and the tensile fracture mode changed from inter-particle dominant fracture to fully dimple ductile fracture

Influences of hot-isostatic-pressing temperature on microstructure, tensile properties and tensile fracture mode of Inconel 718 powder compact

Energy Technology Data Exchange (ETDEWEB)

Chang, Litao [Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China); University of Chinese Academy of Sciences, Beijing (China); Sun, Wenru; Cui, Yuyou [Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China); Yang, Rui, E-mail: ryang@imr.ac.cn [Institute of Metal Research, Chinese Academy of Sciences, Shenyang (China)

2014-04-01

Inconel 718 powders have been hot-isostatic-pressed (HIPed) at representative temperatures to investigate the variations in microstructure, tensile properties and tensile fracture mode of the powder compact. Microstructure of the powder compacts were characterized by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and so on. The results showed that the interdendritic precipitates inherited from the powders were partially retained in the powder compacts when the powders were HIPed at or below 1210 °C but were eliminated when HIPed at and above 1260 °C. The grain size uniformity of the powder compacts first increases and then decreases with increasing HIPing temperature. Prior particle boundaries (PPBs) were observed in the powder compacts HIPed at and below 1260 °C but was eliminated when HIPed at 1275 °C. The PPBs were decorated with carbide particles, the amount of the carbide particles at the PPBs decreases with increasing HIPing temperature. Most of the PPBs were pinned by the carbide particles in the compacts HIPed at 1140 °C. When the HIPing temperature was increased to 1210 °C and 1260 °C, a large number of PPBs de-pinned and moved beyond the pinning carbide particles, leading to grain growth and leaving carbide particles at the site of the original PPBs within the new grains. With increasing HIPing temperature, the 0.2% yield strength of the powder compacts at 650 °C decreases, the tensile elongation increases, and the tensile fracture mode changed from inter-particle dominant fracture to fully dimple ductile fracture.

Effect of pressing temperature on the mechanical properties of waste styrofoam filled sawdust composite

Science.gov (United States)

Nasution, H.; Harahap, H.; Riani, R.; Pelawi, A. I.

2018-02-01

This study has investigated the effect of pressing temperature on mechanical properties of waste styrofoam composite filled with sawdust. The waste styrofoam as the matrix was mixed with sawdust as filler and maleic anhydride (6%wt) as a compatibilizer. The weight fraction ratio between matrix and filler 70:30 (wt) and wood fiber size of 100 mesh were conducted. The pressing temperatures were investigated using a hot press with temperatures varied viz. 120, 130, 150, and 170 °C. Surface modification was applied to sawdust to diminish its polarity so that it could be compatible with the non-polar waste styrofoam matrix. Composites were evaluated using Instron and impact tester machine to investigate the tensile strength and impact strength of the material, respectively. The result indicated that tensile strength has decreased with the increase of pressing temperature where the largest tensile strength is at 130 °C of 33 MPa. The same trend has occurred on impact strength, where the value has reached of 300 J/cm2 on pressing temperature of 130 °C. From scanning electron microscopy (SEM) analysis it is also confirmed that during impact test, the resistance of the composite which has been pressed at the temperature of 130 °C have given better morphology than the composite at 170 °C.

Hot forging of roll-cast high aluminum content magnesium alloys

Science.gov (United States)

Kishi, Tomohiro; Watari, Hisaki; Suzuki, Mayumi; Haga, Toshio

2017-10-01

This paper reports on hot forging of high aluminum content magnesium alloy sheets manufactured using horizontal twin-roll casting. AZ111 and AZ131 were applied for twin-roll casting, and a hot-forging test was performed to manufacture high-strength magnesium alloy components economically. For twin-roll casting, the casting conditions of a thick sheet for hot forging were investigated. It was found that twin-roll casting of a 10mm-thick magnesium alloy sheet was possible at a roll speed of 2.5m/min. The grain size of the cast strip was 50 to 70µm. In the hot-forging test, blank material was obtained from as-cast strip. A servo press machine with a servo die cushion was used to investigate appropriate forging conditions (e.g., temperature, forging load, and back pressure) for twin-roll casts (TRCs) AZ111 and AZ131. It was determined that high aluminum content magnesium alloy sheets manufactured using twin-roll casting could be forged with a forging load of 150t and a back pressure of 3t at 420 to 430°C. Applying back pressure during hot forging effectively forged a pin-shaped product.

Fabrication of Hadfield-Cored Multi-layer Steel Sheet by Roll-Bonding with 1.8-GPa-Strength-Grade Hot-Press-Forming Steel

Science.gov (United States)

Chin, Kwang-Geun; Kang, Chung-Yun; Park, Jaeyeong; Lee, Sunghak

2018-05-01

An austenitic Hadfield steel was roll-bonded with a 1.8-GPa-strength-grade martensitic hot-press-forming (HPF) steel to fabricate a multi-layer steel (MLS) sheet. Near the Hadfield/HPF interface, the carburized and decarburized layers were formed by the carbon diffusion from the Hadfield (1.2%C) to HPF (0.35%C) layers, and could be regarded as kinds of very thin multi-layers of 35 μm in thickness. The tensile test and fractographic data indicated that the MLS sheet was fractured abruptly within the elastic range by the intergranular fracture occurred in the carburized layer. This was because C was mainly segregated at prior austenite grain boundaries in the carburized layer, which weakened grain boundaries to induce the intergranular fracture. In order to solve the intergranular facture problem, the MLS sheet was tempered at 200 °C. The stress-strain curve of the tempered MLS sheet lay between those of the HPF and Hadfield sheets, and a rule of mixtures was roughly satisfied. Tensile properties of the MLS sheet were dramatically improved after the tempering, and the intergranular fracture was erased completely. In particular, the yield strength up to 1073 MPa along with the high strain hardening and excellent ductility of 32.4% were outstanding because the yield strength over 1 GPa was hardly achieved in conventional austenitic steels.

RELATIONSHIP BETWEEN COMPACTING PRESSURE AND CONDITIONS IN PRESSING CHAMBER DURING BIOMASS PRESSING

Directory of Open Access Journals (Sweden)

Peter Križan

2016-02-01

Full Text Available In this paper, we will present the impact of the conditions in pressing chambers during the pressing of wooden briquettes. The conditions in pressing chambers can significantly impact the resulting compacting pressure required for the pressing of briquettes. In the introduction, we show which parameters of the pressing chamber during pressing can impact the resulting compacting pressure. The experiment results which are shown in this paper described the detected impact of some important pressing chamber parameters. This experiment aims to detect the pressing chamber length impact and the impact of the way of pressing. By setting the pressing conditions, we will be able to achieve the suitable resulting compacting pressure with respect to the required final briquettes quality.

Hot-Spot Ignition Mechanisms for Explosives and Propellants

Science.gov (United States)

Field, J. E.; Bourne, N. K.; Palmer, S. J. P.; Walley, S. M.

1992-05-01

This paper describes the response of explosives to stress and impact and in particular the mechanisms of `hot-spot' production. Samples in the form of single crystals, powder layers, pressed pellets, gels, polymer bonded explosives (PBXs) and propellants have been studied. Techniques used include a drop-weight facility with transparent anvils which allows photography at microsecond framing intervals, an instrumented drop-weight machine, a miniaturized Hopkinson bar system for high strain rate property measurement, laser speckle for studying the deformation and fracture of PBXs, an automated system for analysing speckle patterns and heat sensitive film for recording the positions and temperatures of hot spots. Polishing and staining methods have been developed to observe the microstructure of PBXs and failure during quasi-static loading. Ignition, when it occurred, took place at local hot-spot sites. Evidence is discussed for a variety of ignition mechanisms including adiabatic shear of the explosive, adiabatic heating of trapped gases during cavity collapse, viscous flow, friction, fracture and shear of added particles and triboluminescent discharge.

Hot Embossing for Whole Teflon Superhydrophobic Surfaces

Directory of Open Access Journals (Sweden)

Jie Li

2018-06-01

Full Text Available In this paper, we report a simple fabrication process of whole Teflon superhydrophobic surfaces, featuring high-aspect-ratio (>20 nanowire structures, using a hot embossing process. An anodic aluminum oxide (AAO membrane is used as the embossing mold for the fabrication of high-aspect-ratio nanowires directly on a Teflon substrate. First, high-aspect-ratio nanowire structures of Teflon are formed by pressing a fluorinated ethylene propylene (FEP sheet onto a heated AAO membrane at 340 °C, which is above the melting point of FEP. Experimental results show that the heating time and aspect ratios of nanopores in the AAO mold are critical to the fidelity of the hot embossed nanowire structures. It has also been found that during the de-molding step, a large adhesive force between the AAO mold and the molded FEP greatly prolongs the length of nanowires. Contact angle measurements indicate that Teflon nanowires make the surface superhydrophobic. The reliability and robustness of superhydrophobicity is verified by a long-term (~6.5 h underwater turbulent channel flow test. After the first step of hot-embossing the Teflon nanowires, microstructures are further superimposed by repeating the hot embossing process, but this time with microstructured silicon substrates as micromolds and at a temperature lower than the melting temperature of the FEP. The results indicate that the hot embossing process is also an effective way to fabricate hierarchical micro/nanostructures of whole Teflon, which can be useful for applications of Teflon material, such as superhydrophobic surfaces.

Structure and magnetic properties of hot deformed Nd2Fe14B magnets doped with DyHx nanoparticles

Science.gov (United States)

Wang, C. G.; Yue, M.; Zhang, D. T.; Liu, W. Q.; Zhang, J. X.

2016-04-01

Commercial NdFeB powders mixed with DyHx nanoparticles are hot pressed and hot deformed into anisotropic magnets by Spark Plasma Sintering (SPS). The hot deformed magnet exhibits strong c-axis crystallographic texture. The coercivity of the magnet doped with 1.0 wt% DyHx is increased by 66.7%, compared with the magnet without DyHx, while the remanence decreases only by 3%. TEM observation shows that there exists a continuous (Nd,Dy)2Fe14B layer between Nd-rich phase and NdFeB main phase.

WordPress Bible

CERN Document Server

Brazell, Aaron

2010-01-01

The WordPress Bible provides a complete and thorough guide to the largest self hosted blogging tool. This guide starts by covering the basics of WordPress such as installing and the principles of blogging, marketing and social media interaction, but then quickly ramps the reader up to more intermediate to advanced level topics such as plugins, WordPress Loop, themes and templates, custom fields, caching, security and more. The WordPress Bible is the only complete resource one needs to learning WordPress from beginning to end.

Justification and manufacturing quality assurance for the use of hot Isostatically pressed, reactor coolant system components in PWR plant

International Nuclear Information System (INIS)

Sulley, J. L.; Hookham, I. D.

2008-01-01

This paper presents an overview of the work undertaken by Rolls-Royce to introduce Hot Isostatically Pressed (HIP) components into Pressurised Water Reactor plant. It presents the work from a design justification and manufacturing quality assurance perspective, rather than from a pure metallurgical perspective, although some metallurgical and mechanical property comparisons with the traditional forged material are presented. Although the HIP process is not new, it was new in its application to Rolls-Royce designed nuclear reactor plant. In order to satisfy the regulatory requirement of 'Proven Engineering Practices' with regard to the introduction of new material processes, and to provide a robust manufacturing substantiation leg of a multi-legged safety case, Rolls-Royce has implemented an evolving, staged approach, starting with HIP bonding of solid valve seats into small bore valve pressure boundaries. This was followed by powder HIP consolidation of leak-limited, thin-walled toroids, and has culminated in the powder HIP consolidation of components, such as steam generator headers, large bore valves and pipe sections. The paper provides an overview of each of these stages and the approach taken with respect to justification. The paper describes the benefits that Rolls-Royce has realised so far through the introduction of HIPed components, and improvements planned for the future. Structural integrity benefits are described, such as improved grain structure, mechanical properties, and ultrasonic inspection. Project-based benefits are also described, such as provision of an alternative strategic sourcing route, cost and lead-time reduction. A full description is provided of key quality assurance steps applied to the process to ensure a high quality product is delivered commensurate with a high integrity nuclear application. 2008 Rolls-Royce plc. (authors)

Improving Dryer and Press Efficiencies Through Combustion of Hydrocarbon Emissions

Energy Technology Data Exchange (ETDEWEB)

Sujit Banerjee

2005-10-31

Emission control devices on dryers and presses have been legislated into the industry, and are now an integral part of the drying system. These devices consume large quantities of natural gas and electricity and down-sizing or eliminating them will provide major energy savings. The principal strategy taken here focuses on developing process changes that should minimize (and in some cases eliminate) the need for controls. A second approach is to develop lower-cost control options. It has been shown in laboratory and full-scale work that Hazardous Air Pollutants (HAPs) emerge mainly at the end of the press cycle for particleboard, and, by extension, to other prod-ucts. Hence, only the air associated with this point of the cycle need be captured and treated. A model for estimating terpene emissions in the various zones of veneer dryers has been developed. This should allow the emissions to be concentrated in some zones and minimized in others, so that some of the air could be directly released without controls. Low-cost catalysts have been developed for controlling HAPs from dryers and presses. Catalysts conventionally used for regenerative catalytic oxidizers can be used at much lower temperatures for treating press emissions. Fluidized wood ash is an especially inexpensive mate-rial for efficiently reducing formaldehyde in dryer emissions. A heat transfer model for estimating pinene emissions from hot-pressing strand for the manufacture of flakeboard has been constructed from first principles and validated. The model shows that most of the emissions originate from the 1-mm layer of wood adjoining the platen surface. Hence, a simple control option is to surface a softwood mat with a layer of hardwood prior to pressing. Fines release a disproportionate large quantity of HAPs, and it has been shown both theo-retically and in full-scale work that particles smaller than 400 µm are principally responsible. Georgia-Pacific is considering green

Selective Electron Beam Manufacturing of Ti-6Al-4V Strips: Effect of Build Orientation, Columnar Grain Orientation, and Hot Isostatic Pressing on Tensile Properties

Science.gov (United States)

Wang, J.; Tang, H. P.; Yang, K.; Liu, N.; Jia, L.; Qian, M.

2018-03-01

Many novel designs for additive manufacturing (AM) contain thin-walled (≤ 3 mm) sections in different orientations. Selective electron beam melting (SEBM) is particularly suited to AM of such thin-walled titanium components because of its high preheating temperature and high vacuum. However, experimental data on SEBM of Ti-6Al-4V thin sections remains scarce because of the difficulty and high cost of producing long, thin and smooth strip tensile specimens (see Fig. 1). In this study, 80 SEBM Ti-6Al-4V strips (180 mm long, 42 mm wide, 3 mm thick) were built both vertically (V-strips) and horizontally (H-strips). Their density, microstructure and tensile properties were investigated. The V-strips showed clearly higher tensile strengths but lower elongation than the H-strips. Hot isostatic pressing (HIP) produced the same lamellar α-β microstructures in terms of the average α-lath thickness in both types of strips. The retained prior-β columnar grain boundaries after HIP showed no measurable influence on the tensile properties, irrespective of their length and orientation, because of the formation of randomly distributed fine α-laths.[Figure not available: see fulltext.

WordPress for dummies

CERN Document Server

Sabin-Wilson, Lisa

2014-01-01

The bestselling WordPress guide, fully updated to cover the 2013 enhancements WordPress has millions of users, and this popular guide has sold more than 105,000 copies in its previous editions. With the newest releases of WordPress, author and WordPress expert Lisa Sabin-Wilson has completely updated the book to help you use and understand all the latest features. You'll learn about both the hosted WordPress.com version and the more flexible WordPress.org, which requires third-party hosting. Whether you're switching to WordPress from another blogging platform or just beginning to blog, you'll

Reciprocating pellet press

Science.gov (United States)

Jones, Charles W.

1981-04-07

A machine for pressing loose powder into pellets using a series of reciprocating motions has an interchangeable punch and die as its only accurately machines parts. The machine reciprocates horizontally between powder receiving and pressing positions. It reciprocates vertically to press, strip and release a pellet.

Press Advertising – Varieties and Sub-Varieties. Methods of Promoting the Press

OpenAIRE

Mikosz, Joanna

2016-01-01

In the text entitled “Press advertising – varieties and sub-varieties. Methods of promoting the press”, the author discusses press advertising, which is a fast developing mass-media phenomenon. Modernity has granted press advertising a high quality of print and paper, as well as Infinite possibilities of combining various promotional forms with the press. The author argues that press advertising is one of the best ways in which a company can communicate with the market. Its advantage is, abov...

Physical and mechanical properties of parallel strand lumber made from hot pre-pressed long strand oil palm trunk waste

Science.gov (United States)

Fridiyanti, Inayah; Massijaya, M. Y.

2018-03-01

This research was focused on the utilization of oil palm trunk waste as a Parallel Strand Lumber (PSL) raw material. This research aimed to analyze the effect of adhesive types and glue spreads to the physical and mechanical properties of PSL. The adhesive types used were isocyanate and urea formaldehyde adhesives. The glue spreads used were 150 g/m2 and 300 g/m2. The research results showed that the moisture content of PSL ranged from 9.30% to 11.80%. The PSL density ranged from 0.64 to 0.78 g/cm3. The volume shrinkage ranged from 5.69 to 7.17%. Modulus of Elasticity (MOE) parallel to the grain and edge side ranged from 51.6 × 103 to 98.3 × 103 kg/cm2, and 62.1 × 103 to 99.9 × 103 kg/cm2, respectively. The Modulus of Rupture (MOR) parallel to the grain and edge side ranged from 269 to 724 kg/cm2 and 342 to 728 kg/cm2, respectively. The PSL hardness perpendicular to the grain, parallel to the grain and the edge side ranged from 135 to 300 kg/cm2, 87 to 321 kg/cm2, and 128 to 251 kg/cm2, respectively. The compressive strength ranged from 181 to 231 kg/cm2. The best adhesive and glue spreads of PSL was isocyanate with glue spread 300 g/m2. PSL made from hot pre-pressed long strand of oil palm trunk waste bonded by isocyanate fulfill JAS 1152: 2007. However, those of bonded by urea formaldehyde failed to fulfill the standard. The physical and mechanical properties of PSL made from oil palm trunk were better compared to those of solid oil palm trunk.

Microstructural and Microhardness Evolution from Homogenization and Hot Isostatic Pressing on Selective Laser Melted Inconel 718: Structure, Texture, and Phases

Directory of Open Access Journals (Sweden)

Raiyan Seede

2018-05-01

Full Text Available In this work, the microstructure, texture, phases, and microhardness of 45° printed (with respect to the build direction homogenized, and hot isostatically pressed (HIP cylindrical IN718 specimens are investigated. Phase morphology, grain size, microhardness, and crystallographic texture at the bottom of each specimen differ from those of the top due to changes in cooling rate. High cooling rates during the printing process generated a columnar grain structure parallel to the building direction in the as-printed condition with a texture transition from (001 orientation at the bottom of the specimen to (111 orientation towards the specimen top based on EBSD analysis. A mixed columnar and equiaxed grain structure associated with about a 15% reduction in texture is achieved after homogenization treatment. HIP treatment caused significant grain coarsening, and engendered equiaxed grains with an average diameter of 154.8 µm. These treatments promoted the growth of δ-phase (Ni3Nb and MC-type brittle (Ti, NbC carbides at grain boundaries. Laves phase (Fe2Nb was also observed in the as-printed and homogenized specimens. Ostwald ripening of (Ti, NbC carbides caused excessive grain growth at the bottom of the HIPed IN718 specimens, while smaller grains were observed at their top. Microhardness in the as-fabricated specimens was 236.9 HV and increased in the homogenized specimens by 19.3% to 282.6 HV due to more even distribution of secondary precipitates, and the nucleation of smaller grains. A 36.1% reduction in microhardness to 180.5 HV was found in the HIPed condition due to   γ ″ phase dissolution and differences in grain morphology.

WordPress For Dummies

CERN Document Server

Sabin-Wilson, Lisa

2011-01-01

The bestselling guide to WordPress, fully updated to help you get your blog going! Millions of bloggers rely on WordPress, the popular, free blogging platform. This guide covers all the features and improvements in the most up-to-date version of WordPress. Whether you are switching to WordPress from another blogging platform or just starting your first blog, you'll find the advice in this friendly guide gets you up to speed on both the free-hosted WordPress.com version and WordPress.org, which requires the purchase of web hosting services, and figure out which version is best for you. You'll b

Solid-State Recycling of Light Metal Reinforced Inclusions by Equal Channel Angular Pressing: A Review

Directory of Open Access Journals (Sweden)

Al-Alimi Sami.

2017-01-01

Full Text Available Solid-state recycling of light metals reinforced inclusions through hot Equal Channel Angular Pressing (ECAP is performed to directly recycle metal scraps and reduce cost of material in engineering applications. The ECAP is one of the most important method in severe plastic deformation (SPD that can convert light metals into finished products. This paper reviews several experimental and numerical works that have been done to investigate the effects of the ECAP parameters such as die angles, material properties, outer corner angle, friction coefficient, temperature, size of chips, pressing force, ram speed and direct effects of number of passes on the strain distributions. It also includes the performance enhancement of aluminium matrix composite reinforced ceramic-based particles that derived from direct recycled aluminium chips for sustainable manufacturing practices.

Hot Deformation Behavior of Hot-Extruded AA7175 Through Hot Torsion Tests.

Science.gov (United States)

Lee, Se-Yeon; Jung, Taek-Kyun; Son, Hyeon-Woo; Kim, Sang-Wook; Son, Kwang-Tae; Choi, Ho-Joon; Oh, Sang-Ho; Lee, Ji-Woon; Hyun, Soong-Keun

2018-03-01

The hot deformation behavior of hot-extruded AA7175 was investigated with flow curves and processing maps through hot torsion tests. The flow curves and the deformed microstructures revealed that dynamic recrystallization (DRX) occurred in the hot-extruded AA7175 during hot working. The failure strain was highest at medium temperature. This was mainly influenced by the dynamic precipitation of fine rod-shaped MgZn2. The processing map determined the optimal deformation condition for the alloy during hot working.

Influence of heat treatment on microstructure and tensile behavior of a hot isostatically pressed nickel-based superalloy

Energy Technology Data Exchange (ETDEWEB)

Qiu, Chunlei, E-mail: c.qiu@bham.ac.uk [School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Wu, Xinhua; Mei, Junfa [School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Andrews, Paul; Voice, Wayne [Rolls-Royce Plc, Derby DE24 8BJ (United Kingdom)

2013-11-25

Highlights: •Post-HIP heat treatment led to refined microstructure and improved tensile properties. •Deformation occurred mainly by forming stacking faults in γ′ at RT and elevated temperature. •Net-shape HIPed RR1000 failed in a transgranular fracture mode. -- Abstract: A nickel-based superalloy powder RR1000 has been hot isostatically pressed (HIPed) and heat treated to produce different microstructures. Microstructures were investigated using a scanning electron microscope (SEM). Tensile testing was performed at room temperature and 700 °C and the deformed samples were examined using SEM and transmission electron microscope (TEM). It was found that in the as-HIPed condition the microstructure consisted of coarse and irregular-shaped primary and secondary γ′ together with a low volume fraction of fine γ′ (<50 nm in diameter). Solution treatment below the γ′ solvus followed by air cooling resulted in the formation of finer cuboidal secondary γ′ (350–750 nm) and medium-sized spherical tertiary γ′ (100–200 nm). This led to an improvement of both the 0.2% yield strength and ultimate tensile strength. Ageing of the solution-treated or of the as-HIPed samples at 760 °C resulted in the precipitation of a high population of fine γ′ (around 50 nm) which further increased the strength. Within the resolution limit of the current TEM analysis, deformation at room temperature seemed to occur mainly by dislocations cutting through secondary γ′ and very fine γ′, accompanied by the formation of stacking faults within these precipitates; most of the medium-sized tertiary γ′ precipitates in solution-treated and aged samples were not cut through but were surrounded by dislocations. Deformation at 700 °C happened by dislocations cutting through γ′ precipitates and γ matrix, leading to the formation of extended stacking faults across both γ and γ′. It is suggested that the optimum treatment of the current powder superalloy is to

Influence of heat treatment on microstructure and tensile behavior of a hot isostatically pressed nickel-based superalloy

International Nuclear Information System (INIS)

Qiu, Chunlei; Wu, Xinhua; Mei, Junfa; Andrews, Paul; Voice, Wayne

2013-01-01

Highlights: •Post-HIP heat treatment led to refined microstructure and improved tensile properties. •Deformation occurred mainly by forming stacking faults in γ′ at RT and elevated temperature. •Net-shape HIPed RR1000 failed in a transgranular fracture mode. -- Abstract: A nickel-based superalloy powder RR1000 has been hot isostatically pressed (HIPed) and heat treated to produce different microstructures. Microstructures were investigated using a scanning electron microscope (SEM). Tensile testing was performed at room temperature and 700 °C and the deformed samples were examined using SEM and transmission electron microscope (TEM). It was found that in the as-HIPed condition the microstructure consisted of coarse and irregular-shaped primary and secondary γ′ together with a low volume fraction of fine γ′ (<50 nm in diameter). Solution treatment below the γ′ solvus followed by air cooling resulted in the formation of finer cuboidal secondary γ′ (350–750 nm) and medium-sized spherical tertiary γ′ (100–200 nm). This led to an improvement of both the 0.2% yield strength and ultimate tensile strength. Ageing of the solution-treated or of the as-HIPed samples at 760 °C resulted in the precipitation of a high population of fine γ′ (around 50 nm) which further increased the strength. Within the resolution limit of the current TEM analysis, deformation at room temperature seemed to occur mainly by dislocations cutting through secondary γ′ and very fine γ′, accompanied by the formation of stacking faults within these precipitates; most of the medium-sized tertiary γ′ precipitates in solution-treated and aged samples were not cut through but were surrounded by dislocations. Deformation at 700 °C happened by dislocations cutting through γ′ precipitates and γ matrix, leading to the formation of extended stacking faults across both γ and γ′. It is suggested that the optimum treatment of the current powder superalloy is to

WordPress Bible

CERN Document Server

Brazell, Aaron

2011-01-01

Get the latest word on the biggest self-hosted blogging tool on the marketWithin a week of the announcement of WordPress 3.0, it had been downloaded over a million times. Now you can get on the bandwagon of this popular open-source blogging tool with WordPress Bible, 2nd Edition. Whether you're a casual blogger or programming pro, this comprehensive guide covers the latest version of WordPress, from the basics through advanced application development. If you want to thoroughly learn WordPress, this is the book you need to succeed.Explores the principles of blogging, marketing, and social media

'Ye Olde Hot Aire' : reporting on human contributions to climate change in the UK tabloid press

International Nuclear Information System (INIS)

Boykoff, Maxwell T; Mansfield, Maria

2008-01-01

This letter explores daily print media coverage of climate change in four United Kingdom (UK) tabloid newspapers: The Sun (and News of the World), Daily Mail (and Mail on Sunday), the Daily Express (and Sunday Express), and the Mirror (and Sunday Mirror). Through examinations of content in articles over the last seven years (2000-2006), triangulated with semi-structured interviews of journalists and editors, the study finds that UK tabloid coverage significantly diverged from the scientific consensus that humans contribute to climate change. Moreover, there was no consistent increase in the percentage of accurate coverage throughout the period of analysis and across all tabloid newspapers, and these findings are not consistent with recent trends documented in United States and UK 'prestige press' or broadsheet newspaper reporting. Findings from interviews indicate that inaccurate reporting may be linked to the lack of specialist journalists in the tabloid press. This study therefore contributes to wider discussions of socio-economic inequality, media and the environment. Looking to newspapers that are consumed by typically working class readership, this article contributes to ongoing investigations related to what media representations mean for ongoing science-policy interactions as well as potentialities for public engagement

Hot off the Press.

Science.gov (United States)

Hill, Robert A; Sutherland, Andrew

2018-06-07

A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as mollebenzylanol A from Rhododendron molle.

Treatment of zircaloy cladding hulls by isostatic pressing

International Nuclear Information System (INIS)

Tegman, R.; Burstroem, M.

1984-12-01

A method for the treatment of Zircaloy fuel hulls is proposed. It involves hot isostatic pressing (HIP) for making large, completely densified metallic bodies of the waste. The hulls are packed into a bellows-shaped container of steel. On packing the fuel hulls give a filling factor of only 14%, which is too low for non-deformable compaction in a normal container, but by using a belloped container, a non-deformable compaction can be obtained without any pretreatment of the hulls. Fully dense and mechanically strong blocks of Zircaloy can be fabricated by holding them at temperatures of around 1000 degrees C for three hours. It is also feasible to incorporate the other metallic parts of the fuel bundle, such as top and bottom tie plates and spacers, in the pressing. The HIP-densified hulls provide an effective means of self-containment of radioactive waste due to the excellent corrosion resistance of Zircaloy. A waste loading factor of close to 100% can be realized. Futher, a volume reduction factor of 7 and a surface reduction factor of aout 250 for a 1-ton canister can be achieved. Equilibrium calculations have shown that tritium present in the hulls can quantitatively be contained in the HIPed block. A study has been made of a possible process for industrilscale use. (Author)

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

Science.gov (United States)

Maarefdoust, M.; Kadkhodayan, M.

2010-06-01

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

News/Press Releases

Data.gov (United States)

Office of Personnel Management — A press release, news release, media release, press statement is written communication directed at members of the news media for the purpose of announcing programs...

Head First WordPress

CERN Document Server

Siarto, Jeff

2010-01-01

Whether you're promoting your business or writing about your travel adventures, Head First WordPress will teach you not only how to make your blog look unique and attention-grabbing, but also how to dig into the more complex features of WordPress 3.0 to make your website work well, too. You'll learn how to move beyond the standard WordPress look and feel by customizing your blog with your own URL, templates, plugin functionality, and more. As you learn, you'll be working with real WordPress files: The book's website provides pre-fab WordPress themes to download and work with as you follow al

WordPress multisite administration

CERN Document Server

Longren, Tyler

2013-01-01

This is a simple, concise guide with a step-by-step approach, packed with screenshots and examples to set up and manage a network blog using WordPress.WordPress Multisite Administration is ideal for anyone wanting to familiarize themselves with WordPress Multisite. You'll need to know the basics about WordPress, and having at least a broad understanding of HTML, CSS, and PHP will help, but isn't required.

Application of powder metallurgy and hot rolling processes for manufacturing aluminum/alumina composite strips

Energy Technology Data Exchange (ETDEWEB)

Zabihi, Majed, E-mail: m.zabihi@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Toroghinejad, Mohammad Reza, E-mail: toroghi@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shafyei, Ali, E-mail: shafyei@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

2013-01-10

In this study, aluminum matrix composites (AMC) with 2, 4, 6 and 10 wt% alumina were produced using powder metallurgy (PM), mechanical milling (MM) and vacuum hot pressing (VHP) techniques; then, this was followed by the hot-rolling process. During hot rolling, AMCs with 6 and 10 wt% Al{sub 2}O{sub 3} were fractured whereas strip composites with 2 and 4 wt% Al{sub 2}O{sub 3} were produced successfully. Microstructure and mechanical properties of the samples were investigated by optical and scanning electron microscopes and tensile and hardness tests, respectively. Microscopic evaluations of the hot-rolled composites showed a uniform distribution of alumina particles in the aluminum matrix. It was found that with increasing alumina content in the matrix, tensile strength (TS) and hardness increased and the percentage of elongation also decreased. Scanning electron microscope (SEM) was used to investigate aluminum/alumina interfaces and fracture surfaces of the hot rolled specimens after tensile test. SEM observations demonstrated that the failure mode in the hot-rolled Al-2 wt% Al{sub 2}O{sub 3} composite strips is a typical ductile fracture, while the failure mode was shear ductile fracture with more flat surfaces in Al-4 wt% Al{sub 2}O{sub 3} strips.

Prediction of protein interaction hot spots using rough set-based multiple criteria linear programming.

Science.gov (United States)

Chen, Ruoying; Zhang, Zhiwang; Wu, Di; Zhang, Peng; Zhang, Xinyang; Wang, Yong; Shi, Yong

2011-01-21

Protein-protein interactions are fundamentally important in many biological processes and it is in pressing need to understand the principles of protein-protein interactions. Mutagenesis studies have found that only a small fraction of surface residues, known as hot spots, are responsible for the physical binding in protein complexes. However, revealing hot spots by mutagenesis experiments are usually time consuming and expensive. In order to complement the experimental efforts, we propose a new computational approach in this paper to predict hot spots. Our method, Rough Set-based Multiple Criteria Linear Programming (RS-MCLP), integrates rough sets theory and multiple criteria linear programming to choose dominant features and computationally predict hot spots. Our approach is benchmarked by a dataset of 904 alanine-mutated residues and the results show that our RS-MCLP method performs better than other methods, e.g., MCLP, Decision Tree, Bayes Net, and the existing HotSprint database. In addition, we reveal several biological insights based on our analysis. We find that four features (the change of accessible surface area, percentage of the change of accessible surface area, size of a residue, and atomic contacts) are critical in predicting hot spots. Furthermore, we find that three residues (Tyr, Trp, and Phe) are abundant in hot spots through analyzing the distribution of amino acids. Copyright © 2010 Elsevier Ltd. All rights reserved.

Solar 'hot spots' are still hot

Science.gov (United States)

Bai, Taeil

1990-01-01

Longitude distributions of solar flares are not random but show evidence for active zones (or hot spots) where flares are concentrated. According to a previous study, two hot spots in the northern hemisphere, which rotate with a synodic period of about 26.72 days, produced the majority of major flares, during solar cycles 20 and 21. The more prominent of these two hot spots is found to be still active during the rising part of cycle 22, producing the majority of northern hemisphere major flares. The synodic rotation period of this hot spot is 26.727 + or - 0.007 days. There is also evidence for hot spots in the southern hemisphere. Two hot spots separated by 180 deg are found to rotate with a period of 29.407 days, with one of them having persisted in the same locations during cycles 19-22 and the other, during cycles 20-22.

The Global University Press

Science.gov (United States)

Dougherty, Peter J.

2012-01-01

The modern world's understanding of American university press has long been shaped by university-press books. American university-press books are good international advertisements for the universities whose logos grace their spines. The growth of transnational scholarship and the expansion of digital communications networks are converging in ways…

Hot pressing of U-UC cermets and stoichiometric uranium monocarbide; Preparation par frittage sous charge de cermets U-UC et de monocarbure stoechiometrique

Energy Technology Data Exchange (ETDEWEB)

Dubuisson, J; Houyvet, A; Le Boulbin, E; Lucas, R; Moranville, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

High density fuels, either in uranium monocarbide or in U-UC cermets have been prepared on laboratory-scale, by hot pressing of mixtures of uranium powder and graphite in suitable proportions. Uranium powder is prepared by calcium reduction of UO{sub 2} followed by an acetic leaching at low temperature. An adequate protection-treatment permits the manipulation of the powder in the open air. Uranium and Graphite powders are intimately mixed and then hot pressed in a double effect graphite die at a temperature of 900-1000 deg. C under a charge of 200 kg/cm{sup 2} during 3 hours. A special design of the die avoids the breaking of the graphite during the sintering. In this way, samples are prepared, the characteristics of which are: 1) {+-} 5 pour cent of homogeneity for a ratio height/diameter = 2. 2) almost theoretical density (98 pour cent) 3) low concentration of unreacted carbon (heat treatment of stoichiometric monocarbide can be useful for completion of reaction) 4) the micrographic examination shows: - a network of monocarbide surrounding uranium in the case of low concentration cermets (<2,5 per cent C) - two networks intimately mixed for high concentration cermets (<2,5 per cent C) - a fine grain structure for the monocarbide (10 u). 5) In every case, the X rays examinations show a fine grain structure without any orientation, and no UC{sub 2}. Some indications are given on the physical (thermal cycling, conductibility) and chemical properties (corrosion, reaction with cladding materials). (author)Fren. [French] Une methode de preparation de combustibles de haute densite, soit en monocarbure d'uranium, soit en cermets U-UC, a ete mise au point au laboratoire. Il s'agit du frittage sous charge de melanges de poudres d'uranium et de graphite en proportion convenable. La poudre d'uranium est elaboree par calciothermie de l'oxyde UO{sub 2} suivie d'un lavage acetique a basse temperature. Un traitement de protection adequat pe sa manipulation a l'air. Les poudres

Solar hot spots are still hot

International Nuclear Information System (INIS)

Bai, T.

1990-01-01

Longitude distributions of solar flares are not random but show evidence for active zones (or hot spots) where flares are concentrated. According to a previous study, two hot spots in the northern hemisphere, which rotate with a synodic period of about 26.72 days, produced the majority of major flares, during solar cycles 20 and 21. The more prominent of these two hot spots is found to be still active during the rising part of cycle 22, producing the majority of northern hemisphere major flares. The synodic rotation period of this hot spot is 26.727 + or - 0.007 days. There is also evidence for hot spots in the southern hemisphere. Two hot spots separated by 180 deg are found to rotate with a period of 29.407 days, with one of them having persisted in the same locations during cycles 19-22 and the other, during cycles 20-22. 14 refs

Change of Pressing Chamber Conicalness at Briquetting Process in Briquetting Machine Pressing Chamber

Directory of Open Access Journals (Sweden)

Peter Križan

2012-01-01

Full Text Available In this paper, we will present the impact of the conical shape of a pressing chamber, an important structural parameter. Besides the known impact of the technological parameters of pressing chambers, it is also very important to pay attention to their structural parameters. In the introduction, we present a theoretical analysis of pressing chamber conicalness. An experiment aimed at detecting this impact was performed at our institute, and it showed that increasing the conicalness of a pressing chamber improves the quality of the final briquettes. The conicalness of the pressing chamber has a significanteffect on the final briquette quality and on the construction of briquetting machines. The experimental findings presented here show the importance of this parameter in the briquetting process.

Teach yourself visually WordPress

CERN Document Server

Majure, Janet

2012-01-01

Get your blog up and running with the latest version of WordPress WordPress is one of the most popular, easy-to-use blogging platforms and allows you to create a dynamic and engaging blog, even if you have no programming skills or experience. Ideal for the visual learner, Teach Yourself VISUALLY WordPress, Second Edition introduces you to the exciting possibilities of the newest version of WordPress and helps you get started, step by step, with creating and setting up a WordPress site. Author and experienced WordPress user Janet Majure shares advice, insight, and best practices for taking full

HOT 2015

DEFF Research Database (Denmark)

Hannibal, Sara Stefansen

2016-01-01

HOT samler og formidler 21 literacykyndiges bud på, hvad der er hot, og hvad der bør være hot inden for literacy – og deres begrundelser for disse bud.......HOT samler og formidler 21 literacykyndiges bud på, hvad der er hot, og hvad der bør være hot inden for literacy – og deres begrundelser for disse bud....

Annealing effects on the microstructure and mechanical properties of hot-rolled 14Cr-ODS steel

Science.gov (United States)

Gao, R.; Zhang, T.; Ding, H. L.; Jiang, Y.; Wang, X. P.; Fang, Q. F.; Liu, C. S.

2015-10-01

The oxide dispersion strengthened ferritic steels with nominal composition (weight percent) of Fe-14Cr-2W-0.5Ti-0.06Si-0.2V-0.1Mn-0.05Ta-0.03C-0.3Y2O3 were fabricated by sol-gel method, mechanical alloying, and hot isostatic pressing techniques. The evolution of microstructure and mechanical properties of the hot-rolled specimens with heat treatment was investigated. Tensile strength and hardness of hot-rolled ODS steel are significantly enhanced due to the formation of mechanical twins and high density dislocations. Uniformly dispersed oxide particles (10-40 nm) and fine-grained structure (200-400 nm) are responsible for the superior mechanical properties of the hot-rolled specimen annealed between 650 °C and 850 °C. With further increasing annealing temperature, the grain size of the hot-rolled specimens increases while the size of oxide particles decreases, which leads to lower strength and hardness but better ductility. The tensile strength and total elongation of samples in the rolling direction are higher than those in the transverse direction after the same treatments owing to the grain anisotropy induced by the large mechanical deformation.

Analysis of Institutional Press Releases and its Visibility in the Press

Directory of Open Access Journals (Sweden)

José Antonio Alcoceba-Hernando, Ph.D.

2010-01-01

Full Text Available The relationships between institutional communication and media communication influence the shaping of social representations of public issues. This research article analyses these relationships based on the case study of the external communication of a public institution, the press releases of Spain’s Youth Institute (Instituto de la Juventud, aka, Injuve, during three years and their repercussion in the press during the same period of time. The results obtained in this research allowed drawing conclusions on the types of communication production of the aforementioned institution and the news treatment of such pieces of information by the printed and digital media. The press releases and the news items were studied using quantitative media content analysis which focused, especially, in referential issues like the information treatment, the thematic analysis, youth representations in the case of the releases; and the visibility of the press releases in the making of news

HotRegion: a database of predicted hot spot clusters.

Science.gov (United States)

Cukuroglu, Engin; Gursoy, Attila; Keskin, Ozlem

2012-01-01

Hot spots are energetically important residues at protein interfaces and they are not randomly distributed across the interface but rather clustered. These clustered hot spots form hot regions. Hot regions are important for the stability of protein complexes, as well as providing specificity to binding sites. We propose a database called HotRegion, which provides the hot region information of the interfaces by using predicted hot spot residues, and structural properties of these interface residues such as pair potentials of interface residues, accessible surface area (ASA) and relative ASA values of interface residues of both monomer and complex forms of proteins. Also, the 3D visualization of the interface and interactions among hot spot residues are provided. HotRegion is accessible at http://prism.ccbb.ku.edu.tr/hotregion.

Investigation of the Microstructure and Mechanical Properties of Copper-Graphite Composites Reinforced with Single-Crystal α-Al₂O₃ Fibres by Hot Isostatic Pressing.

Science.gov (United States)

Zhang, Guihang; Jiang, Xiaosong; Qiao, ChangJun; Shao, Zhenyi; Zhu, Degui; Zhu, Minhao; Valcarcel, Victor

2018-06-11

Single-crystal α-Al₂O₃ fibres can be utilized as a novel reinforcement in high-temperature composites owing to their high elastic modulus, chemical and thermal stability. Unlike non-oxide fibres and polycrystalline alumina fibres, high-temperature oxidation and polycrystalline particles boundary growth will not occur for single-crystal α-Al₂O₃ fibres. In this work, single-crystal α-Al₂O₃ whiskers and Al₂O₃ particles synergistic reinforced copper-graphite composites were fabricated by mechanical alloying and hot isostatic pressing techniques. The phase compositions, microstructures, and fracture morphologies of the composites were investigated using X-ray diffraction, a scanning electron microscope equipped with an X-ray energy-dispersive spectrometer (EDS), an electron probe microscopic analysis equipped with wavelength-dispersive spectrometer, and a transmission electron microscope equipped with EDS. The mechanical properties have been measured by a micro-hardness tester and electronic universal testing machine. The results show that the reinforcements were unevenly distributed in the matrix with the increase of their content and there were some micro-cracks located at the interface between the reinforcement and the matrix. With the increase of the Al₂O₃ whisker content, the compressive strength of the composites first increased and then decreased, while the hardness decreased. The fracture and strengthening mechanisms of the composite materials were explored on the basis of the structure and composition of the composites through the formation and function of the interface. The main strengthening mechanism in the composites was fine grain strengthening and solid solution strengthening. The fracture type of the composites was brittle fracture.

WordPress Top Plugins

CERN Document Server

Corbin, Brandon

2010-01-01

Time flies when you're having fun. This is the right way to describe this WordPress Top Plugins book by Brandon Corbin. With real world examples and by showing you the perks of having these plugins installed on your websites, the author is all set to captivate your interest from start to end. Regardless of whether this is your first time working with WordPress, or you're a seasoned WordPress coding ninja, WordPress Top Plugins will walk you through finding and installing the best plugins for generating and sharing content, building communities and reader base, and generating real advertising r

Variation of microstructures and mechanical properties of hot heading process of super heat resisting alloy Inconel 718

International Nuclear Information System (INIS)

Choi, Hong Seok; Ko, Dae Chul; Kim, Byung Min

2007-01-01

Metal forming is the process changing shapes and mechanical properties of the workpiece without initial material reduction through plastic deformation. Above all, because of hot working carried out above recrystallization temperature can be generated large deformation with one blow, it can produce with forging complicated parts or heat resisting super alloy such as Inconel 718 has the worst forgeability. In this paper, we established optimal variation of hot heading process of the Inconel 718 used in heat resisting component and evaluated mechanical properties hot worked product. Die material is SKD61 and initial temperature is 300 .deg. C. Initial billet temperature and punch velocity changed, relatively. Friction coefficient is 0.3 as lubricated condition of hot working. CAE is carried out using DEFORM software before marking the tryout part, and it is manufactured 150 ton screw press with optimal condition. It is know that forming load was decreased according to decreasing punch velocity

Which Freedom of the Press?

DEFF Research Database (Denmark)

Rytter, Jens Elo

2010-01-01

The article surveys the historical and current meaning of "Freedom of the Press" in constitutional and human rights law. Two different conceptions exist, the narrow one defining freedom of the press as the freedom of every one to publish without prior restraint, the broader one defining it as a...... privileged freedom of the organised press to gather and report on information of public interest. These two conceptions have very different answers to the question of whether the press should enjoy some privilege to be exempt from ordinary legislation when such legislation restricts the access of the press to inform...

反应热压制备TiC/Al复合材料的形成途径研究%Investigation on Formation Path of TiC/Al Composite Obtained by Reactive Hot-pressing Technology

Institute of Scientific and Technical Information of China (English)

宋谋胜; 冉茂武

2012-01-01

利用场激发反应热压合成技术研究了Al-Ti-C混合粉末体系制备TiC/Al产物的过程与致密性,并结合DSC实验分析了该体系合成TiC相的形成途径.结果表明,采用反应热压合成法完全能够制备较致密的TiC/Al复合材料.该体系形成TiC相的反应过程为:Ti(s)+3Al(s)=TiAl3(s)→Al(s)=Al(l) →Ti(s)+3 Al(l)=TiAl3(s)→ TiAl3(s)=TiAl3(1)→TiAl3(l)+C(s)=TiC(s)+ Al((l)).混合粉末中的Al不仅作为稀释剂降低体系的反应温度而细化TiC晶粒,还作为反应剂参与了整个反应进程.%Utilizing the field activation reactive hot-pressing (RHP) technology, the process and densificatian of TiC/Al products obtained from Al-Ti-C mixtures system were investigated, eoupied with the DSC experiment to analyze iht formation path of TiC phase in this system. The results show that the dense TiC/Al composite can be fully fabricated by the reactive hot-pressing method. The reaction process of the Al-Ti-C system to form TiC phase can be expressed: Ti(s)+3Al(s)= TiAl3(s) →Al(s)=Al(1)→Ti(,s)+3Al(1)=TiAl,(s)→TiAl3(s)=TiAl3(1)→TiAl3(l)+C(s)=T(C(s)+Al(1). Al in the mixtures plays an important role in serving not only as a diluent to decrease the reaction temperature and thus to refine the TiC grains, but also as an intermediate reactant to participate in the whole reaction process.

Mathematical modelling of wet paper pressing

NARCIS (Netherlands)

Bežanovic, D.

2005-01-01

The aim of this project is to reduce energy costs in paper production by optimising the process in the press section of a paper machine. In this press section water is squeezed as it passes through the press nip. In a modern press section the moisture content of the sheet after three or four presses

Efficient dewatering of bark in heated presses. Survey and pilot-scale trials; Effektivare avvattning av bark i vaermda pressar. Problemkartering samt foersoek i pilotskala

Energy Technology Data Exchange (ETDEWEB)

Haakansson, Martin; Stenstroem, Stig (Lund Inst. of Technology, Lund (SE))

2007-12-15

Dewatering and drying of biofuels such as bark and GROT have received increased importance due to an increased interest to use these products as energy sources. In Sweden there are about 30 bark presses installed, however the amount of available information is very limited about dewatering of bark. The goal with this work is to increase the knowledge about dewatering of bark. Two separate goals have been defined in the project: A. Survey about problems related to dewatering of bark and compilation of operating experiences at Swedish mills. B. Study how different parameters affect bark dewatering at pilot scale experiments. Study different techniques for heating bark and the bark pressing process. The results will mainly be of interest for mills which are handling bark, for municipal power plants who buy wet forest residues (bark, GROT etc.) and for manufacturers of industrial bark pressing equipment. The results show that the dry matter content for birch- and pine bark normally are so high that pressing does not result in dewatering of the barks. Both dry and wet debarking is used and these bark fractions should be pressed separately. On line measurement of the dry matter content for the bark should be used as a standard tool on the bark press. This will facilitate improved control of the bark press during the year. Other conclusions are that smaller bark particles result in an increased dry matter content, large bark- and wood pieces decrease the dewatering in the bark press and that the total residence time in the press nip should be at least 30 seconds. The most common method to take care of bark water is to send it to the evaporators or to the water purification plant. Maintenance of the bark press appears not to be a big problem. Hot pressing can be accomplished in different ways, either the bark press can be heated or the bark can be heated in different ways. The alternatives that have been studied in this project are steaming the bark, heating the bark using

Aluminum-graphite composite produced by mechanical milling and hot extrusion

International Nuclear Information System (INIS)

Flores-Zamora, M.I.; Estrada-Guel, I.; Gonzalez-Hernandez, J.; Miki-Yoshida, M.; Martinez-Sanchez, R.

2007-01-01

Aluminum-graphite composites were produced by mechanical milling followed by hot extrusion. Graphite content was varied between 0 and 1 wt.%. Al-graphite mixtures were initially mixed in a shaker mill without ball, followed by mechanical milling in a High-energy simoloyer mill for 2 h under argon atmosphere. Milled powders were subsequently pressed at ∼950 MPa for 2 min, and next sintered under vacuum for 3 h at 823 K. Finally, sintered products were held for 0.5 h at 823 K and hot extruded using indirect extrusion. Tension and compression tests were carried out to determine the yield stress and maximum stress of the materials. We found that the mechanical resistance increased as the graphite content increased. Microstructural characterization was done by transmission electron microscopy. Al-O-C nanofibers and graphite nanoparticles were observed in extruded samples by transmission electron microscopy. These nanoparticles and nanofibers seemed to be responsible of the reinforcement phenomenon

Effect of standard heat treatment on the microstructure and mechanical properties of hot isostatically pressed superalloy inconel 718

International Nuclear Information System (INIS)

Rao, G. Appa; Kumar, Mahendra; Srinivas, M.; Sarma, D.S.

2003-01-01

Ni-Fe base superalloy, Inconel 718, was processed through powder metallurgy (P/M) hot isostatic pressing (HIP) route. In order to balance the strength and ductility, the HIPed material was given the standard heat treatment, viz. solution treatment at 980 deg. C for 1 h/water quenched (WQ) to room temperature and a two-step ageing treatment consisting of 720 deg. C for 8 h/furnace cooling (FC) at 55 deg. C h -1 to 620 deg. C and holding at 620 deg. C for 8 h before air cooling (AC) to room temperature. Optical microscopy and scanning electron microscopy (SEM) studies on the heat treated alloy have shown a homogeneous microstructure with fine grain size (25 μm) along with the presence of prior particle boundary (PPB) networks. Transmission electron microscopy (TEM) on the heat treated material has revealed the presence of oxides, MC carbides and δ-precipitates at the grain boundaries and a uniform precipitation of fine γ'' and γ' strengthening phases in the matrix. Tensile and stress rupture tests were performed on the heat treated material. While the yield strength (YS) and ultimate tensile strength (UTS) of the HIPed and heat treated alloy at room temperature and 650 deg. C were comparable to those of conventionally processed wrought IN 718, its ductility was lower. The stress rupture life of the HIPed alloy improved marginally due to heat treatment and met the minimum specification requirement of life hours but the rupture ductility was found to be inferior to that of the wrought material. The fractography of the failed samples has revealed the transgranular ductile mode of fracture in the as-solution treated alloy, while intergranular mode of failure with the decohesion of PPBs occurred more predominantly in the aged condition. This change of fracture mode with ageing treatment shows the ductility dependence on the relative strength of the matrix and PPBs. The TEM studies on the deformed alloy have revealed that the brittle oxides and carbides at the prior

Four Theories of the Press.

Science.gov (United States)

Siebert, Fred S.; And Others

A systematic understanding of the press requires an understanding of the social and political structures within which the press operates. This book discusses four theories that have determined the kind of press the Western world has had: authoritarian, libertarian, socially responsible, and Soviet communist. Each chapter discusses press…

WordPress 3.7 complete

CERN Document Server

Król, Karol

2013-01-01

WordPress 3.5 Complete: Third Edition is a comprehensive and step-by-step tutorial packed with screenshots and examples to make it easy and quick to pick it up.This WordPress book is a guide to WordPress for online publishers and web developers. If you are new to blogging and want to create your own blog or website from scratch, then ""WordPress 3.5 Complete: Third Edition"" is for you. No prior knowledge of HTML/CSS or PHP is required.

HOT 2012

DEFF Research Database (Denmark)

Lund, Henriette Romme

Undersøgelse af, hvad der er hot - og hvad der burde være hot på læseområdet med 21 læsekyndige. Undersøgelsen er gennemført siden 2010. HOT-undersøgelsen er foretaget af Nationalt Videncenter for Læsning - Professionshøjskolerne i samarb. med Dansklærerforeningen......Undersøgelse af, hvad der er hot - og hvad der burde være hot på læseområdet med 21 læsekyndige. Undersøgelsen er gennemført siden 2010. HOT-undersøgelsen er foretaget af Nationalt Videncenter for Læsning - Professionshøjskolerne i samarb. med Dansklærerforeningen...

Performance study of protective clothing against hot water splashes: from bench scale test to instrumented manikin test.

Science.gov (United States)

Lu, Yehu; Song, Guowen; Wang, Faming

2015-03-01

Hot liquid hazards existing in work environments are shown to be a considerable risk for industrial workers. In this study, the predicted protection from fabric was assessed by a modified hot liquid splash tester. In these tests, conditions with and without an air spacer were applied. The protective performance of a garment exposed to hot water spray was investigated by a spray manikin evaluation system. Three-dimensional body scanning technique was used to characterize the air gap size between the protective clothing and the manikin skin. The relationship between bench scale test and manikin test was discussed and the regression model was established to predict the overall percentage of skin burn while wearing protective clothing. The results demonstrated strong correlations between bench scale test and manikin test. Based on these studies, the overall performance of protective clothing against hot water spray can be estimated on the basis of the results of the bench scale hot water splashes test and the information of air gap size entrapped in clothing. The findings provide effective guides for the design and material selection while developing high performance protective clothing. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2014.

Smashing WordPress Beyond the Blog

CERN Document Server

Hedengren, Thord Daniel

2011-01-01

Smashing WordPress shows you how to utilize the power of the WordPress platform, and provides a creative spark to help you build WordPress-powered sites that go beyond the obvious. The second edition of Smashing WordPress has been updated for WordPress 3.1+, which includes internal, custom post types, the admin bar, and lots of other useful new features. You will learn the core concepts used to post types, the admin bar, and lots of other useful new features. You will learn the core concepts used to build just about anything in WordPress, resulting in fast deployments and greater design flexib

Smashing WordPress Beyond the Blog

CERN Document Server

Hedengren, Thord Daniel

2012-01-01

The ultimate guide to WordPress, from the world's most popular resource for web designers and developers As one of the hottest tools on the web today for creating a blog, WordPress has evolved to be much more that just a blogging platform and has been pushed beyond its original purpose. With this new edition of a perennially popular WordPress resource, Smashing Magazine offers you the information you need so you can maximize the potential and power of WordPress. WordPress expert Thord Daniel Hedengren takes you beyond the basic blog to show you how to leverage the capabilities of WordPress to

Dry sliding tribological behavior and mechanical properties of Al2024–5 wt.%B4C nanocomposite produced by mechanical milling and hot extrusion

International Nuclear Information System (INIS)

Abdollahi, Alireza; Alizadeh, Ali; Baharvandi, Hamid Reza

2014-01-01

Highlights: • Nanostructured Al2024 and Al2024–B 4 C nanocomposite prepared via mechanical milling. • The milled powders formed by hot pressing and then exposed to hot extrusion. • Tribological behavior and mechanical properties of samples were investigated. • Al2024–B 4 C nanocomposite showed a better wear resistance and mechanical properties. - Abstract: In this paper, tribological behavior and mechanical properties of nanostructured Al2024 alloy produced by mechanical milling and hot extrusion were investigated before and after adding B 4 C particles. Mechanical milling was used to synthesize the nanostructured Al2024 in attrition mill under argon atmosphere up to 50 h. A similar process was used to produce Al2024–5 wt.%B 4 C composite powder. The milled powders were formed by hot pressing and then were exposed to hot extrusion in 750 °C with extrusion ratio of 10:1. To study the microstructure of milled powders and hot extruded samples, optical microscopy, transmission electron microscopy and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometer (EDS) were used. The mechanical properties of samples were also compared together using tension, compression and hardness tests. The wear properties of samples were studied using pin-on-disk apparatus under a 20 N load. The results show that mechanical milling decreases the size of aluminum matrix grains to less than 100 nm. The results of mechanical and wear tests also indicate that mechanical milling and adding B 4 C particles increase strength, hardness and wear resistance of Al2024 and decrease its ductility remarkably

ENZYMATIC HYDROLYSIS LIGNIN DERIVED FROM CORN STOVER AS AN INTRINSTIC BINDER FOR BIO-COMPOSITES MANUFACTURE: EFFECT OF FIBER MOISTURE CONTENT AND PRESSING TEMPERATURE ON BOARDS’ PROPERTIES

Directory of Open Access Journals (Sweden)

Guanben Du

2011-02-01

Full Text Available Binderless fiberboards from enzymatic hydrolysis lignin (EHL and cotton stalk fibers were prepared under various manufacturing conditions, and their physico-mechanical properties were evaluated. Full factorial experimental design was used to assess the effect of fiber moisture content and pressing temperature on boards’ properties. In addition, differential scanning calorimetry (DSC was used to obtain the glass transition temperature (Tg of EHL. We found that both fiber moisture content and pressing temperature had significant effects on binderless fiberboards’ properties. High fiber moisture content and pressing temperature are suggested to contribute to the self-bonding improvement among fibers with lignin-rich surface mainly by thermal softening enzymatic hydrolysis lignin. In this experiment, the optimized pressing temperature applied in binderless fiberboard production should be as high as 190°C in accordance with the EHL Tg value of 189.4°C, and the fiber moisture content should be limited to less than 20% with a higher board density of 950 kg/m3 to avoid the delamination of boards during hot pressing.

Muscle activation when performing the chest press and shoulder press on a stable bench vs. a Swiss ball.

Science.gov (United States)

Uribe, Brandon P; Coburn, Jared W; Brown, Lee E; Judelson, Daniel A; Khamoui, Andy V; Nguyen, Diamond

2010-04-01

The aim of this study was to examine the effects of a stable surface (bench) vs. an unstable surface (Swiss ball) on muscle activation when performing the dumbbell chest press and shoulder press. Sixteen healthy men (24.19 +/- 2.17 years) performed 1 repetition maximum (1RM) tests for the chest press and shoulder press on a stable surface. A minimum of 48 hours post 1RM, subjects returned to perform 3 consecutive repetitions each of the chest press and shoulder press at 80% 1RM under 4 different randomized conditions (chest press on bench, chest press on Swiss ball, shoulder press on bench, shoulder press on Swiss ball). Electromyography was used to assess muscle activation of the anterior deltoid, pectoralis major, and rectus abdominus. The results revealed no significant difference in muscle activation between surface types for either exercise. This suggests that using an unstable surface neither improves nor impairs muscle activation under the current conditions. Coaches and other practitioners can expect similar muscle activation when using a Swiss ball vs. a bench.

Rigorous assessment and integration of the sequence and structure based features to predict hot spots

Directory of Open Access Journals (Sweden)

Wang Yong

2011-07-01

Full Text Available Abstract Background Systematic mutagenesis studies have shown that only a few interface residues termed hot spots contribute significantly to the binding free energy of protein-protein interactions. Therefore, hot spots prediction becomes increasingly important for well understanding the essence of proteins interactions and helping narrow down the search space for drug design. Currently many computational methods have been developed by proposing different features. However comparative assessment of these features and furthermore effective and accurate methods are still in pressing need. Results In this study, we first comprehensively collect the features to discriminate hot spots and non-hot spots and analyze their distributions. We find that hot spots have lower relASA and larger relative change in ASA, suggesting hot spots tend to be protected from bulk solvent. In addition, hot spots have more contacts including hydrogen bonds, salt bridges, and atomic contacts, which favor complexes formation. Interestingly, we find that conservation score and sequence entropy are not significantly different between hot spots and non-hot spots in Ab+ dataset (all complexes. While in Ab- dataset (antigen-antibody complexes are excluded, there are significant differences in two features between hot pots and non-hot spots. Secondly, we explore the predictive ability for each feature and the combinations of features by support vector machines (SVMs. The results indicate that sequence-based feature outperforms other combinations of features with reasonable accuracy, with a precision of 0.69, a recall of 0.68, an F1 score of 0.68, and an AUC of 0.68 on independent test set. Compared with other machine learning methods and two energy-based approaches, our approach achieves the best performance. Moreover, we demonstrate the applicability of our method to predict hot spots of two protein complexes. Conclusion Experimental results show that support vector machine

Rigorous assessment and integration of the sequence and structure based features to predict hot spots

Science.gov (United States)

2011-01-01

Background Systematic mutagenesis studies have shown that only a few interface residues termed hot spots contribute significantly to the binding free energy of protein-protein interactions. Therefore, hot spots prediction becomes increasingly important for well understanding the essence of proteins interactions and helping narrow down the search space for drug design. Currently many computational methods have been developed by proposing different features. However comparative assessment of these features and furthermore effective and accurate methods are still in pressing need. Results In this study, we first comprehensively collect the features to discriminate hot spots and non-hot spots and analyze their distributions. We find that hot spots have lower relASA and larger relative change in ASA, suggesting hot spots tend to be protected from bulk solvent. In addition, hot spots have more contacts including hydrogen bonds, salt bridges, and atomic contacts, which favor complexes formation. Interestingly, we find that conservation score and sequence entropy are not significantly different between hot spots and non-hot spots in Ab+ dataset (all complexes). While in Ab- dataset (antigen-antibody complexes are excluded), there are significant differences in two features between hot pots and non-hot spots. Secondly, we explore the predictive ability for each feature and the combinations of features by support vector machines (SVMs). The results indicate that sequence-based feature outperforms other combinations of features with reasonable accuracy, with a precision of 0.69, a recall of 0.68, an F1 score of 0.68, and an AUC of 0.68 on independent test set. Compared with other machine learning methods and two energy-based approaches, our approach achieves the best performance. Moreover, we demonstrate the applicability of our method to predict hot spots of two protein complexes. Conclusion Experimental results show that support vector machine classifiers are quite

Transformation plasticity and hot pressing

International Nuclear Information System (INIS)

Chaklader, A.C.D.

1975-01-01

The transformation plasticity during the phase transition of quartz to cristobalite, monoclinic reversible tetragonal of zirconia, metakaolin to a spinel phase, and brucite to periclase was investigated by studying their compaction characteristics. Viscous flow was found to be the predominant mechanism of mass transport (after an initial particle rearrangement stage) in the case of quartz to cristobalite phase change where the transformation was associated with the formation of an intermediate amorphous silica phase. The results on the monoclinic reversible tetragonal transformation of zirconia indicated that it is most likely controlled by internal strain induced by the stress associated with the volume change (ΔV/V) and the flow stress of the weaker phase. Particle movement and deformation of the weaker phase (possibly tetragonal) may be the manifestation of this plasticity. The plasticity in the case of metakaolin to a spinel phase appeared to start before the exothermic reaction (generally encountered in a dta plot) and may be diffusion controlled. The plasticity encountered during brucite to periclase transformation may be the combined effect of disintegration of precursor particles, vapor-phase lubrication and some deformability of freshly formed very fine MgO particles

Annealing effects on the microstructure and mechanical properties of hot-rolled 14Cr-ODS steel

International Nuclear Information System (INIS)

Gao, R.; Zhang, T.; Ding, H.L.; Jiang, Y.; Wang, X.P.; Fang, Q.F.; Liu, C.S.

2015-01-01

The oxide dispersion strengthened ferritic steels with nominal composition (weight percent) of Fe–14Cr–2W-0.5Ti-0.06Si-0.2V-0.1Mn-0.05Ta-0.03C-0.3Y_2O_3 were fabricated by sol–gel method, mechanical alloying, and hot isostatic pressing techniques. The evolution of microstructure and mechanical properties of the hot-rolled specimens with heat treatment was investigated. Tensile strength and hardness of hot-rolled ODS steel are significantly enhanced due to the formation of mechanical twins and high density dislocations. Uniformly dispersed oxide particles (10–40 nm) and fine-grained structure (200–400 nm) are responsible for the superior mechanical properties of the hot-rolled specimen annealed between 650 °C and 850 °C. With further increasing annealing temperature, the grain size of the hot-rolled specimens increases while the size of oxide particles decreases, which leads to lower strength and hardness but better ductility. The tensile strength and total elongation of samples in the rolling direction are higher than those in the transverse direction after the same treatments owing to the grain anisotropy induced by the large mechanical deformation.

Investing in a Large Stretch Press

Science.gov (United States)

Choate, M.; Nealson, W.; Jay, G.; Buss, W.

1986-01-01

Press for forming large aluminum parts from plates provides substantial economies. Study assessed advantages and disadvantages of investing in large stretch-forming press, and also developed procurement specification for press.

Structure and magnetic properties of hot deformed Nd{sub 2}Fe{sub 14}B magnets doped with DyH{sub x} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Wang, C.G.; Yue, M., E-mail: yueming@bjut.edu.cn; Zhang, D.T.; Liu, W.Q.; Zhang, J.X.

2016-04-15

Commercial NdFeB powders mixed with DyH{sub x} nanoparticles are hot pressed and hot deformed into anisotropic magnets by Spark Plasma Sintering (SPS). The hot deformed magnet exhibits strong c-axis crystallographic texture. The coercivity of the magnet doped with 1.0 wt% DyH{sub x} is increased by 66.7%, compared with the magnet without DyH{sub x}, while the remanence decreases only by 3%. TEM observation shows that there exists a continuous (Nd,Dy){sub 2}Fe{sub 14}B layer between Nd-rich phase and NdFeB main phase. - Highlights: • The hot deformed magnet exhibits strong c-axis crystallographic texture. • The coercivity of the magnet significantly improved, and the remanence decreases slight. • TEM observation shows that there exists a continuous (Nd,Dy){sub 2}Fe{sub 14}B layer.

Hot Flashes

Science.gov (United States)

Hot flashes Overview Hot flashes are sudden feelings of warmth, which are usually most intense over the face, neck and chest. Your skin might redden, as if you're blushing. Hot flashes can also cause sweating, and if you ...

AUPress: A Comparison of an Open Access University Press with Traditional Presses

Science.gov (United States)

McGreal, Rory; Chen, Nian-Shing

2011-01-01

This study is a comparison of AUPress with three other traditional (non-open access) Canadian university presses. The analysis is based on the rankings that are correlated with book sales on Amazon.com and Amazon.ca. Statistical methods include the sampling of the sales ranking of randomly selected books from each press. The results of one-way…

Professional WordPress design and development

CERN Document Server

Williams, Brad; Stern, Hal

2014-01-01

The highest rated WordPress development and design book on the market is back with an all new third edition. Professional WordPress is the only WordPress book targeted to developers, with advanced content that exploits the full functionality of the most popular CMS in the world. Fully updated to align with WordPress 4.1, this edition has updated examples with all new screenshots, and full exploration of additional tasks made possible by the latest tools and features. You will gain insight into real projects that currently use WordPress as an application framework, as well as the basic usage a

Miniature ambulatory skin conductance monitor and algorithm for investigating hot flash events

Energy Technology Data Exchange (ETDEWEB)

Bahr, Dennis E; Webster, John G; Shults, Mark [Department of Research and Development, Bahr Management, Inc., Middleton, WI 53562 (United States); Grady, Deborah; Creasman, Jennifer; Macer, Judy [Department of Medicine, University of California, San Francisco, CA 94115 (United States); Kronenberg, Fredi [School of Medicine, Stanford University, Palo Alto, CA 94305 (United States); Tyler, Mitchell; Zhou, Xin [Department of Biomedical Engineering, University of Wisconsin, Madison, WI 53706 (United States)

2014-02-15

A skin conductance monitoring system was developed and shown to reliably acquire and record hot flash events in both supervised laboratory and unsupervised ambulatory conditions. The 7.2 × 3.8 × 1.2 cm{sup 3} monitor consists of a disposable adhesive patch supporting two hydrogel electrodes and a reusable, miniaturized, enclosed electronic circuit board that snaps onto the electrodes. The monitor measures and records the skin conductance for seven days without external wires or telemetry and has an event marker that the subject can press whenever a hot flash is experienced. The accuracy of the system was demonstrated by comparing the number of hot flashes detected by algorithms developed during this research with the number identified by experts in hot flash studies. Three methods of detecting hot flash events were evaluated, but only two were fully developed. The two that were developed were an artificial neural network and a matched filter technique with multiple kernels implemented as a sliding form of the Pearson product-moment correlation coefficient. Both algorithms were trained on a ‘development’ cohort of 17 women and then validated using a second similar ‘validation’ cohort of 20. All subjects were between the ages of 40 and 60 and self-reported ten or more hot flashes per day over a three day period. The matched filter was the most accurate with a mean sensitivity of 0.92 and a mean specificity of 0.90 using the data from the development cohort and a mean sensitivity of 0.92 and a mean specificity of 0.87 using the data from the validation cohort. The matched filter was the method implemented in our processing software. (paper)

BuddyPress theme development

CERN Document Server

Lister, Tammie

2013-01-01

This book is a hands-on tutorial guide to using BuddyPress.This book is great for designers and developers who are looking to learn how to develop BuddyPress themes. It's assumed that the reader has some understanding of Wordpress and is familiar with CSS and HTML.

Growth kinetics and microstructural evolution during hot isostatic pressing of U-10 wt.% Mo monolithic fuel plate in AA6061 cladding with Zr diffusion barrier

Science.gov (United States)

Park, Y.; Yoo, J.; Huang, K.; Keiser, D. D.; Jue, J. F.; Rabin, B.; Moore, G.; Sohn, Y. H.

2014-04-01

Phase constituents and microstructure changes in RERTR fuel plate assemblies as functions of temperature and duration of hot-isostatic pressing (HIP) during fabrication were examined. The HIP process was carried out as functions of temperature (520, 540, 560 and 580 °C for 90 min) and time (45-345 min at 560 °C) to bond 6061 Al-alloy to the Zr diffusion barrier that had been co-rolled with U-10 wt.% Mo (U10Mo) fuel monolith prior to the HIP process. Scanning and transmission electron microscopies were employed to examine the phase constituents, microstructure and layer thickness of interaction products from interdiffusion. At the interface between the U10Mo and Zr, following the co-rolling, the UZr2 phase was observed to develop adjacent to Zr, and the α-U phase was found between the UZr2 and U10Mo, while the Mo2Zr was found as precipitates mostly within the α-U phase. The phase constituents and thickness of the interaction layer at the U10Mo-Zr interface remained unchanged regardless of HIP processing variation. Observable growth due to HIP was only observed for the (Al,Si)3Zr phase found at the Zr/AA6061 interface, however, with a large activation energy of 457 ± 28 kJ/mole. Thus, HIP can be carried to improve the adhesion quality of fuel plate without concern for the excessive growth of the interaction layer, particularly at the U10Mo-Zr interface with the α-U, Mo2Zr, and UZr2 phases.

Growth kinetics and microstructural evolution during hot isostatic pressing of U-10 wt.% Mo monolithic fuel plate in AA6061 cladding with Zr diffusion barrier

International Nuclear Information System (INIS)

Park, Y.; Yoo, J.; Huang, K.; Keiser, D.D.; Jue, J.F.; Rabin, B.; Moore, G.; Sohn, Y.H.

2014-01-01

Phase constituents and microstructure changes in RERTR fuel plate assemblies as functions of temperature and duration of hot-isostatic pressing (HIP) during fabrication were examined. The HIP process was carried out as functions of temperature (520, 540, 560 and 580 °C for 90 min) and time (45–345 min at 560 °C) to bond 6061 Al-alloy to the Zr diffusion barrier that had been co-rolled with U-10 wt.% Mo (U10Mo) fuel monolith prior to the HIP process. Scanning and transmission electron microscopies were employed to examine the phase constituents, microstructure and layer thickness of interaction products from interdiffusion. At the interface between the U10Mo and Zr, following the co-rolling, the UZr 2 phase was observed to develop adjacent to Zr, and the α-U phase was found between the UZr 2 and U10Mo, while the Mo 2 Zr was found as precipitates mostly within the α-U phase. The phase constituents and thickness of the interaction layer at the U10Mo-Zr interface remained unchanged regardless of HIP processing variation. Observable growth due to HIP was only observed for the (Al,Si) 3 Zr phase found at the Zr/AA6061 interface, however, with a large activation energy of 457 ± 28 kJ/mole. Thus, HIP can be carried to improve the adhesion quality of fuel plate without concern for the excessive growth of the interaction layer, particularly at the U10Mo-Zr interface with the α-U, Mo 2 Zr, and UZr 2 phases

Conférence de presse | Press Conference

CERN Multimedia

CERN. Geneva; Bejar Alonso, Isabel

2018-01-01

10:00-11:00 Conférence de presse en présence de Lucio Rossi, chef du projet LHC à Haute Luminosité et Isabel Bejar Alonso, chargée de la configuration, de la qualité et des ressources du projet LHC à Haute Luminosité.

HOT 2011

DEFF Research Database (Denmark)

Lund, Henriette Romme

En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager 21 læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet.......En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager 21 læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet....

Hot isostatically-pressed aluminosilicate glass-ceramic with natural crystalline analogues for immobilizing the calcined high-level nuclear waste at the Idaho Chemical Processing Plant

International Nuclear Information System (INIS)

Raman, S.

1993-12-01

The additives Si, Al, MgO, P 2 O 5 were mechanically blended with fluorinelsodium calcine in varying proportions. The batches were vacuum sealed in stainless steel canisters and hot isostatically pressed at 20,000 PSI and 1000 C for 4 hours. The resulting suite of glass-ceramic waste forms parallels the natural rocks in microstructural and compositional heterogeneity. Several crystalline phases ar analogous in composition and structure to naturally occurring minerals. Additional crystalline phases are zirconia and Ca-Mg borate. The glasses are enriched in silica and alumina. Approximately 7% calcine elements occur dissolved in this glass and the total glass content in the waste forms averages 20 wt%. The remainder of the calcine elements are partitioned into crystalline phases at 75 wt% calcine waste loading. The waste forms were tested for chemical durability in accordance with the MCC1-test procedure. The leach rates are a function of the relative proportions of additives and calcine, which in turn influence the composition and abundances of the glass and crystalline phases. The DOE leach rate criterion of less than 1 g/m 2 -day is met by all the elements B, Cs and Na are increased by lowering the melt viscosity. This is related to increased crystallization or devitrification with increases in MgO addition. This exploratory work has shown that the increases in waste loading occur by preferred partitioning of the calcine components among crystalline and glass phases. The determination of optimum processing parameters in the form of additive concentration levels, homogeneous blending among the components, and pressure-temperature stabilities of phases must be continued to eliminate undesirable effects of chemical composition, microstructure and glass devitrification

Comparação das Práticas Ambientais nos Hotéis da Galiza e do Norte de Portugal

Directory of Open Access Journals (Sweden)

María Dolores Sánchez-Fernández

2016-09-01

Full Text Available Na presente pesquisa pretendemos estudar a articulação da Teoria Institucional e as práticas ambientais nos hotéis de três, quatro e cinco estrelas, localizados na Galiza (Espanha e no Norte de Portugal. Para o desenvolvimento desta pesquisa, pretendemos responder às seguintes perguntas: existe uma configuração institucionalizada em hotéis de três, quatro e cinco estrelas situados na Galiza e Norte de Portugal, que influencia o desenvolvimento de práticas ambientais? E quais dos mecanismos propostos pela Teoria Institucional exerce uma maior pressão sobre o desempenho ambiental na nossa unidade em estudo? Para esse efeito propomos quatro hipóteses e acreditamos que a Teoria Institucional é uma abordagem válida que tenta explicar o comportamento das organizações. Como principal resultado desta investigação sobressai que a nossa unidade de estudo está incorporada num ambiente institucional claramente marcado por pressões coercitivas e normativas.

WordPress all-in-one for dummies

CERN Document Server

Sabin-Wilson, Lisa

2013-01-01

Top WordPress guide, now fully updated for the latest WordPress release! This updated new edition comprises one of the largest collections of practical intermediate to advanced information on WordPress. Fully updated for the latest WordPress release, this in-depth book covers it all, from setting up your software to publishing your site, using SEO and social media, developing and using plug-ins, running multiple sites with WordPress, and more. Veteran author Lisa Sabin-Wilson is a top authority on WordPress, and she and her co-authors pack this book with essential and easy-to-follo

Press to compress contaminated wastes drums

International Nuclear Information System (INIS)

Prevost, J.

1993-01-01

This patent describes a press for contaminated wastes drums pressing. The press is made of a structure comprising a base and an upper stringer bind to the base by vertical bearers, a compression system comprising a main cylinder and a ram, connected to the upper stringer

ISS Expedition 08 Press Kit

Data.gov (United States)

National Aeronautics and Space Administration — Press kit for ISS mission Expedition 08 from 10/2003-04/2004. Press kits contain information about each mission overview, crew, mission timeline, benefits, and media...

Bullying the media : Cultural and climato-economic readings of press repression versus press freedom

NARCIS (Netherlands)

Van de Vliert, E.

Journalists and media assistants in many places are murdered, imprisoned, censored, threatened, and similarly harrassed. Here I document that, and explain why, there are three climato-economic niches of press repression versus press freedom as part of broader syndromes of national culture. A

HOT 2014

DEFF Research Database (Denmark)

Lund, Henriette

Undersøgelse af, hvad der er hot - og hvad der burde være hot på læseområdet med 21 læsekyndige. Undersøgelsen er gennemført siden 2010. HOT-undersøgelsen er foretaget af Nationalt Videncenter for Læsning - Professionshøjskolerne i samarb. med Dansklærerforeningen...

Activation of Selected Core Muscles during Pressing

Directory of Open Access Journals (Sweden)

Thomas W. Nesser

2015-10-01

Full Text Available Introduction: Unstable surface training is often used to activate core musculature during resistance training. Unfortunately, unstable surface training is risky and leads to detraining. Purpose: The purpose of this study was to determine core muscle activation during stable surface ground-based lifts. Methods: Fourteen recreational trained and former NCAA DI athletes (weight 84.2 ± 13.3 kg; height 176.0 ± 9.5 cm; age 20.9 ± 2.0 years volunteered for participation. Subjects completed two ground-based lifts: overhead press and push-press. Surface EMG was recorded from 4 muscles on the right side of the body (Rectus Abdominus (RA, External Oblique (EO, Transverse Abdominus (TA, and Erector Spinae (ES. Results: Paired sample T-tests identified significant muscle activation differences between the overhead press and the push-press included ES and EO. Average and peak EMG for ES was significantly greater in push-press (P<0.01. Anterior displacement of COP was significantly greater in push-press compared to overhead press during the eccentric phase. Conclusion: The push-press was identified as superior in core muscle activation when compared to the overhead pressing exercise. Keywords: torso, stability, weight lifting, resistance training

The effect of hot working on structure and strength of a precipitation strengthened austenitic stainless steel

International Nuclear Information System (INIS)

Mataya, M.C.; Carr, M.J.; Krauss, G.

1984-01-01

The development of microstructure and strength during forging a γ' strengthened austenitic stainless steel, JBK-75, was investigated. The specimens were deformed in a strain range of 0.16 to 1.0, from 800 0 C to 1080 0 C at approximate strain rates of 2 (press forging) and 2 X 10 3 S -1 (high energy rate forging). Mechanical properties were determined by tensile testing as-forged and forged and aged specimens. The alloy exhibited a wide variety of structures and properties within the range of forging parameters studied. Deformation at the higher strain rate via high energy rate forging resulted in unrecovered substructures and high strengths at low forging temperatures, and static recrystallization and low strengths at high temperatures. In contrast, however, deformation at the lower strain rate via press forging resulted in retention of the well developed subgrain structure and associated high strength produced at high forging temperatures and strains. At lower temperatures and strains during press forging a subgrain structure formed preferentially at high angle grain boundaries, apparently by a creep-type deformation mechanism. Dynamic recrystallization was not an important restoration mechanism for any of the forging conditions. The results are interpreted on the basis of stacking fault energy and the accumulation of strain energy during hot working. The significance of microstructural differences for equivalent deformation conditions (iso-Z, where Z is the Zener-Holloman parameter) is discussed in relation to the utilization of Z for predicting hot work structures and strengths. Aging showed that γ' precipitation is not affected by substructure and that the strengthening contributions were independent and additive. Applications for these findings are discussed in terms of process design criteria

ZrC Ceramics Prepared by Self-propagating High-temperature Synthesis/Single Action Pressing

Directory of Open Access Journals (Sweden)

CHENG Yong

2017-01-01

Full Text Available ZrC ceramics were prepared by mechanical axial compression of self-propagating high-temperature synthesis/single action pressing (SHS/SAP.The effects of pressure on microstructure and densification of the products,as well as the relationship between displacement/variation of the load curve and SHS reaction,were studied.The structure and properties of the products were investigated by XRD and SEM.In addition,the density was measured by the drain away liquid method.Meanwhile,universal testing machine was used to record the displacement and load curve alternations.The results indicate that products are mainly composed of ZrC phase,the process of exhaust are accelerated as the increasing of pressure as well,leading to the smaller size of porosity and crystal particles.Density manifested as an increasing pattern by the elevated pressure with no longer change at 80MPa.Due to the strong attenuation of pressure at the peak of temperature,the density of the production is only 65.7% in 120MPa.The end point of the SHS reaction and the plastic time of the products can be monitored by displacement and load curve.The results provide evidence for the application of self-propagating high-temperature synthesis/pseudo-hot isostatic pressing to further improve the density of ceramics.

On the Role of Processing Parameters in Producing Recycled Aluminum AA6061 Based Metal Matrix Composite (MMC-AlR Prepared Using Hot Press Forging (HPF Process

Directory of Open Access Journals (Sweden)

Azlan Ahmad

2017-09-01

Full Text Available Solid-state recycling, which involves the direct recycling of scrap metal into bulk material using severe plastic deformation, has emerged as a potential alternative to the conventional remelting and recycling techniques. Hot press forging has been identified as a sustainable direct recycling technique that has fewer steps and maintains excellent material performance. An experimental investigation was conducted to explore the hardness and density of a recycled aluminum-based metal matrix composite by varying operating temperature and holding time. A mixture of recycled aluminum, AA6061, and aluminum oxide were simultaneously heated to 430, 480, and 530 °C and forged for 60, 90, and 120 min. We found a positive increase in microhardness and density for all composites. The hardness increased approximately 33.85%, while density improved by about 15.25% whenever the temperature or the holding time were increased. Based on qualitative analysis, the composite endures substantial plastic deformation due to the presence of hardness properties due to the aluminum oxide embedded in the aluminum matrix. These increases were significantly affected by the operating temperature; the holding time also had a subordinate role in enhancing the metal matrix composite properties. Furthermore, in an effort to curb the shortage of primary resources, this study reviewed the promising performance of secondary resources produced by using recycled aluminum and aluminum oxide as the base matrix and reinforcement constituent, respectively. This study is an outline for machining practitioners and the manufacturing industry to help increase industry sustainability with the aim of preserving the Earth for our community in the future.

On the Role of Processing Parameters in Producing Recycled Aluminum AA6061 Based Metal Matrix Composite (MMC-AlR) Prepared Using Hot Press Forging (HPF) Process.

Science.gov (United States)

Ahmad, Azlan; Lajis, Mohd Amri; Yusuf, Nur Kamilah

2017-09-19

Solid-state recycling, which involves the direct recycling of scrap metal into bulk material using severe plastic deformation, has emerged as a potential alternative to the conventional remelting and recycling techniques. Hot press forging has been identified as a sustainable direct recycling technique that has fewer steps and maintains excellent material performance. An experimental investigation was conducted to explore the hardness and density of a recycled aluminum-based metal matrix composite by varying operating temperature and holding time. A mixture of recycled aluminum, AA6061, and aluminum oxide were simultaneously heated to 430, 480, and 530 °C and forged for 60, 90, and 120 min. We found a positive increase in microhardness and density for all composites. The hardness increased approximately 33.85%, while density improved by about 15.25% whenever the temperature or the holding time were increased. Based on qualitative analysis, the composite endures substantial plastic deformation due to the presence of hardness properties due to the aluminum oxide embedded in the aluminum matrix. These increases were significantly affected by the operating temperature; the holding time also had a subordinate role in enhancing the metal matrix composite properties. Furthermore, in an effort to curb the shortage of primary resources, this study reviewed the promising performance of secondary resources produced by using recycled aluminum and aluminum oxide as the base matrix and reinforcement constituent, respectively. This study is an outline for machining practitioners and the manufacturing industry to help increase industry sustainability with the aim of preserving the Earth for our community in the future.

HOT 2010

DEFF Research Database (Denmark)

Lund, Henriette Romme

En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager en række læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet. Undersøgelsen er gentaget hvert år siden 2010.......En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager en række læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet. Undersøgelsen er gentaget hvert år siden 2010....

HOT 2013

DEFF Research Database (Denmark)

Lund, Henriette Romme

En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager en række læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet. Undersøgelsen er gentaget hvert år siden 2010.......En undersøgelse af, hvad der er hot - og burde være hot på læseområdet. I undersøgelsen deltager en række læsekyndige fra praksisfeltet, professionshøjskolerne og forskningsområdet. Undersøgelsen er gentaget hvert år siden 2010....

Suppression of sawtooth oscillations due to hot electrons and hot ions

International Nuclear Information System (INIS)

Zhang, Y.Z.; Berk, H.L.

1989-01-01

The theory of m = 1 kink mode stabilization is discussed in the presence of either magnetically trapped hot electrons or hot ions. For instability hot ion requires particles peaked inside the q = 1 surface, while hot electrons require that its pressure profile be increasing at the q = 1 surface. Experimentally observed sawtooth stabilization usually occurs with off-axis heating with ECRH and near axis heating with ICRH. Such heating may produce the magnetically trapped hot particle pressure profiles that are consistent with theory. 17 refs., 2 figs

Growth kinetics and microstructural evolution during hot isostatic pressing of U-10 wt.% Mo monolithic fuel plate in AA6061 cladding with Zr diffusion barrier

Energy Technology Data Exchange (ETDEWEB)

Park, Y.; Yoo, J.; Huang, K. [Advanced Materials Processing and Analysis Center, Department of Materials Science and Engineering, University of Central Florida, Orlando, FL 32816 (United States); Keiser, D.D.; Jue, J.F.; Rabin, B.; Moore, G. [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83401 (United States); Sohn, Y.H., E-mail: Yongho.sohn@ucf.edu [Advanced Materials Processing and Analysis Center, Department of Materials Science and Engineering, University of Central Florida, Orlando, FL 32816 (United States)

2014-04-01

Phase constituents and microstructure changes in RERTR fuel plate assemblies as functions of temperature and duration of hot-isostatic pressing (HIP) during fabrication were examined. The HIP process was carried out as functions of temperature (520, 540, 560 and 580 °C for 90 min) and time (45–345 min at 560 °C) to bond 6061 Al-alloy to the Zr diffusion barrier that had been co-rolled with U-10 wt.% Mo (U10Mo) fuel monolith prior to the HIP process. Scanning and transmission electron microscopies were employed to examine the phase constituents, microstructure and layer thickness of interaction products from interdiffusion. At the interface between the U10Mo and Zr, following the co-rolling, the UZr{sub 2} phase was observed to develop adjacent to Zr, and the α-U phase was found between the UZr{sub 2} and U10Mo, while the Mo{sub 2}Zr was found as precipitates mostly within the α-U phase. The phase constituents and thickness of the interaction layer at the U10Mo-Zr interface remained unchanged regardless of HIP processing variation. Observable growth due to HIP was only observed for the (Al,Si){sub 3}Zr phase found at the Zr/AA6061 interface, however, with a large activation energy of 457 ± 28 kJ/mole. Thus, HIP can be carried to improve the adhesion quality of fuel plate without concern for the excessive growth of the interaction layer, particularly at the U10Mo-Zr interface with the α-U, Mo{sub 2}Zr, and UZr{sub 2} phases.

Radioactive spent resins conditioning by the hot super-compaction process

International Nuclear Information System (INIS)

Roth, Andreas; Centner, Baudouin; Lemmens, Alain

2007-01-01

Spent ion exchanger media are considered to be problematic waste that, in many cases, requires special approaches and precautions during its immobilization to meet the acceptance criteria for disposal. The waste acceptance criteria define, among others, the quality of waste forms for disposal, and therefore will sometimes define appropriate treatment options. The selection of treatment options for spent ion exchange materials must consider their physical and chemical characteristics. Basically, the main methods for the treatment of spent organic ion exchange materials, following to pretreatment methods are: - Direct immobilization, producing a stable end product by using Cement, Bitumen, Polymer or High Integrity Containers, - The destruction of the organic compounds by using Thermochemical processes or Oxidation to produce an inorganic intermediate product that may or may not be further conditioned for storage and/or disposal, - The complete removal of the resin inner structural water by a thermal process. After a thorough technical economical analysis, Tractebel Engineering selected the Resin Hot Compaction Process to be installed at Tihange Nuclear Power Plant. The Resin Hot Compaction Process is used to make dense homogenous organic blocks from a wide range of particulate waste. In this process spent resins are first dewatered and dried to remove the inner structural water content. The drying takes place in a drying vessel that holds the contents of two 200 L drums (Figure). In the oil heated drying and mixing unit, the resins are heated to the necessary process temperature for the hot pressing step and then placed into special metal drums, which are automatically lidded and immediately transferred to a high force compactor. After high force compaction the pellets are transferred to a measuring unit, where the dose rate, height and weight are automatically measured and recorded. A volume reduction factor of approximately up to four (depending on the type of

Two layer powder pressing

International Nuclear Information System (INIS)

Schreiner, H.

1979-01-01

First, significance and advantages of sintered materials consisting of two layers are pointed out. By means of the two layer powder pressing technique metal powders are formed resulting in compacts with high accuracy of shape and mass. Attributes of basic powders, different filling methods and pressing techniques are discussed. The described technique is supposed to find further applications in the field of two layer compacts in the near future

Chip compacting press; Jido kirikuzu asshukuki

Energy Technology Data Exchange (ETDEWEB)

Oura, K. [Yuken Kogyo Co. Ltd., Kanagawa (Japan)

1998-08-15

The chips exhausted from various machine tools are massy, occupy much space and make working environment worse by staying added cutting oil to lower part. The chips are exhausted as a result of machining and have not constant quality. Even if used material is same the chips have various shapes and properties by kinds and machining methods of used machine tools, and are troublesome materials from a standpoint of their treatment. Pressing and solidification of the chips have frequently been tried. A chip compacting press introduced in this paper, a relatively cheap chip compacting press aimed for relatively small scale chip treatment, and has such characteristics and effects as follows. Chips are pressed and solidified by each raw material, so fractional management can be easily conducted. As casting metal chips and curled chips of iron and aluminum can be pressed to about 1/3 to 1/5 and about 1/40, respectively, space saving can be conducted. Chip compacting pressing upgrades its transporting efficiency to make possible to reduce its transporting cost. As chip solidification controls its oxidation and most cutting oil are removed, chips are easy to recycle. 2 figs., 1 tab.

WordPress web application development

CERN Document Server

Ratnayake, Rakhitha Nimesh

2013-01-01

An extensive, practical guide that explains how to adapt WordPress features, both conventional and trending, for web applications.This book is intended for WordPress developers and designers who have the desire to go beyond conventional website development to develop quality web applications within a limited time frame and for maximum profit. Experienced web developers who are looking for a framework for rapid application development will also find this to be a useful resource. Prior knowledge with of WordPress is preferable as the main focus will be on explaining methods for adapting WordPres

Professional WordPress Plugin Development

CERN Document Server

Williams, Brad; Tadlock, Justin

2011-01-01

Taking WordPress to the next level with advanced plugin developmentWordPress is used to create self-hosted blogs and sites, and it's fast becoming the most popular content management system (CMS) on the Web. Now you can extend it for personal, corporate and enterprise use with advanced plugins and this professional development guide. Learn how to create plugins using the WordPress plugin API: utilize hooks, store custom settings, craft translation files, secure your plugins, set custom user roles, integrate widgets, work with JavaScript and AJAX, create custom post types. You'll find a practic

WordPress 24-Hour Trainer

CERN Document Server

Plumley, George

2011-01-01

The eagerly anticipated second edition, completely updated for WordPress 3.1 As an open source content management system, WordPress allows users to easily build feature-rich web sites with no programming experience. This unique book-and-video package is a friendly, self-paced beginners guide to the latest release of WordPress. Lessons are focused on practical, everyday tasks that users will need to create and maintain their sites: entering new content, creating new pages, managing menus, making content search-engine friendly. Plus you'll find lots of tips based on years of experience teaching

A comparative study between spiral-filter press and belt press implemented in a cloudy apple juice production process.

Science.gov (United States)

De Paepe, Domien; Coudijzer, Katleen; Noten, Bart; Valkenborg, Dirk; Servaes, Kelly; De Loose, Marc; Diels, Ludo; Voorspoels, Stefan; Van Droogenbroeck, Bart

2015-04-15

In this study, advantages and disadvantages of the innovative, low-oxygen spiral-filter press system were studied in comparison with the belt press, commonly applied in small and medium size enterprises for the production of cloudy apple juice. On the basis of equivalent throughput, a higher juice yield could be achieved with spiral-filter press. Also a more turbid juice with a higher content of suspended solids could be produced. The avoidance of enzymatic browning during juice extraction led to an attractive yellowish juice with an elevated phenolic content. Moreover, it was found that juice produced with spiral-filter press demonstrates a higher retention of phenolic compounds during the downstream processing steps and storage. The results demonstrates the advantage of the use of a spiral-filter press in comparison with belt press in the production of a high quality cloudy apple juice rich in phenolic compounds, without the use of oxidation inhibiting additives. Copyright © 2014 Elsevier Ltd. All rights reserved.

Powder metallurgy Al–6Cr–2Fe–1Ti alloy prepared by melt atomisation and hot ultra-high pressure compaction

International Nuclear Information System (INIS)

Dám, Karel; Vojtěch, Dalibor; Průša, Filip

2013-01-01

Al--6Cr--2Fe--1Ti alloy was prepared by melt atomisation into rapidly solidified powder. The powder was compacted using uniaxial hot compression at an ultra-high pressure (6 GPa). The samples were pressed at 300, 400 and 500 °C. The structure, mechanical properties and thermal stability were examined and compared with those of the commercially available Al--12Si--1Cu--1Mg--1Ni casting alloy, which is considered thermally stable. It was shown that the hot compression at ultra-high pressure results in a compact and pore-free material with excellent mechanical properties. The elevated pressing temperatures were found to be effective at increasing the mechanical stability after applying the ultra-high pressure. The results of thermal stability testing revealed that the mechanical properties do not change significantly at high temperature, even after 100 h of annealing at 400 °C. In addition, the Al--6Cr--2Fe--1Ti alloy exhibited very good creep resistance. A comparison between the commercial Al--12Si--1Cu--1Mg--1Ni alloy and the powder metallurgy alloy shows that this alloy has significantly better mechanical properties and thermal stability.

Powder metallurgy Al-6Cr-2Fe-1Ti alloy prepared by melt atomisation and hot ultra-high pressure compaction

Energy Technology Data Exchange (ETDEWEB)

Dam, Karel, E-mail: Karel.Dam@vscht.cz [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Vojtech, Dalibor; Prusa, Filip [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague, Technicka 5, 166 28 Prague 6 (Czech Republic)

2013-01-10

Al--6Cr--2Fe--1Ti alloy was prepared by melt atomisation into rapidly solidified powder. The powder was compacted using uniaxial hot compression at an ultra-high pressure (6 GPa). The samples were pressed at 300, 400 and 500 Degree-Sign C. The structure, mechanical properties and thermal stability were examined and compared with those of the commercially available Al--12Si--1Cu--1Mg--1Ni casting alloy, which is considered thermally stable. It was shown that the hot compression at ultra-high pressure results in a compact and pore-free material with excellent mechanical properties. The elevated pressing temperatures were found to be effective at increasing the mechanical stability after applying the ultra-high pressure. The results of thermal stability testing revealed that the mechanical properties do not change significantly at high temperature, even after 100 h of annealing at 400 Degree-Sign C. In addition, the Al--6Cr--2Fe--1Ti alloy exhibited very good creep resistance. A comparison between the commercial Al--12Si--1Cu--1Mg--1Ni alloy and the powder metallurgy alloy shows that this alloy has significantly better mechanical properties and thermal stability.

HOT STARS WITH HOT JUPITERS HAVE HIGH OBLIQUITIES

International Nuclear Information System (INIS)

Winn, Joshua N.; Albrecht, Simon; Fabrycky, Daniel; Johnson, John Asher

2010-01-01

We show that stars with transiting planets for which the stellar obliquity is large are preferentially hot (T eff > 6250 K). This could explain why small obliquities were observed in the earliest measurements, which focused on relatively cool stars drawn from Doppler surveys, as opposed to hotter stars that emerged more recently from transit surveys. The observed trend could be due to differences in planet formation and migration around stars of varying mass. Alternatively, we speculate that hot-Jupiter systems begin with a wide range of obliquities, but the photospheres of cool stars realign with the orbits due to tidal dissipation in their convective zones, while hot stars cannot realign because of their thinner convective zones. This in turn would suggest that hot Jupiters originate from few-body gravitational dynamics and that disk migration plays at most a supporting role.

The Effect of Hot Working on Structure and Strength of a Precipitation Strengthened Austenitic Stainless Steel

Science.gov (United States)

Mataya, M. C.; Carr, M. J.; Krauss, G.

1984-02-01

The development of microstructure and strength during forging in a γ' strengthened austenitic stainless steel, JBK-75, was investigated by means of forward extrusion of cylindrical specimens. The specimens were deformed in a strain range of 0.16 to 1.0, from 800°C to 1080°C, and at approximate strain rates of 2 (press forging) and 2 × 103 s-1 (high energy rate forging), and structures examined by light and transmission microscopy. Mechanical properties were determined by tensile testing as-forged and forged and aged specimens. The alloy exhibited an extremely wide variety of structures and properties within the range of forging pzrameters studied. Deformation at the higher strain rate via high energy rate forging resulted in unrecovered substructures and high strengths at low forging temperatures, and static recrystallization and low strengths at high temperatures. In contrast, however, deformation at the lower strain rate via press forging resulted in retention of the well developed subgrain structure and associated high strength produced at high forging temperatures and strains. At lower temperatures and strains during press forging a subgrain structure formed preferentially at high angle grain boundaries, apparently by a creep-type deformation mechanism. Dynamic recrystallization was not an important restoration mechanism for any of the forging conditions. The results are interpreted on the basis of stacking fault energy and the accumulation of strain energy during hot working. The significance of observed microstructural differences for equivalent deformation conditions (iso-Z, where Z is the Zener-Holloman parameter) is discussed in relation to the utilization of Z for predicting hot work structures and strengths. Aging showed that the γ' precipitation process is not affected by substructure and that the strengthening contributions, from substructure and precipitation, were independent and additive. Applications for these findings are discussed in terms

Indre spenninger og ytre press

DEFF Research Database (Denmark)

Ibsen, Bjarne

2011-01-01

Anmeldelse af bogen 'Norsk idrett. Indre spenninger og ytre press' redigeret af Dag Vidar Hanstad, Gunnar Breivik, Mari Kristin Sisjord og Hans B. Skaset og udgivet af forlaet akilles.......Anmeldelse af bogen 'Norsk idrett. Indre spenninger og ytre press' redigeret af Dag Vidar Hanstad, Gunnar Breivik, Mari Kristin Sisjord og Hans B. Skaset og udgivet af forlaet akilles....

WordPress 3 Cookbook

CERN Document Server

Shreves, Ric

2011-01-01

This is a Packt Cookbook, which means it contains step-by-step instructions to achieve a particular goal or solve a particular problem. There are plenty of screenshots and explained practical tasks to make comprehension quick and easy. This book is not specifically for developers or programmers; rather it can be used by anyone who wants to get more out of their WordPress blog by following step-by-step instructions. A basic knowledge of PHP/XHTML/CSS/WordPress is desirable but not necessary.

WordPress all-in-one for dummies

CERN Document Server

Sabin-Wilson, Lisa; Palmer, Kevin

2011-01-01

A convenient how-to guide for maximizing your WordPress experience. WordPress is a state-of-the-art blog publishing platform with nearly ten million active installations. Eight minibooks provide you with expanded coverage of the most important topics to the WordPress community, such as WordPress basics, theme designs, plug-in development, social media integration, SEO, customization, and running multiple sites. Veteran author Lisa Sabin-Wilson leads an authoritative team of authors who offer their unique knowledge and skillset while sharing invaluable advice for maximizing your site's potentia

Control system for glassing hot presses

Energy Technology Data Exchange (ETDEWEB)

Howell, J.F.

1984-06-13

A software programmable control system has been developed that automates the glass fusing process used in the production of semiconductor thermopile elements. The new control system replaces an older, mostly manual, electromechanical design. This report describes the new control design and its functional features.

Hot-isostatic pressing (HIP). Pt. 2

International Nuclear Information System (INIS)

Bayer, E.; Moser, G.; Seilstorfer, H.

1981-01-01

After the description of the microstructure and strengthening mechanism of nickel- and cobalt-base superalloys, claims for the production of suitable powders for the HIP-technology are pointed out and methods to its realization are discussed. Taking the manufacture of turbine discs (ultrasonic form) as an example the possibilities of the near-net-shape-technology are shown. Investigations on mechanical properties and on microstructures are carried out to determine the effect of HIP-process-parameters on these features. (orig.) [de

Pellet presses for remote fuel fabrication

International Nuclear Information System (INIS)

Densley, P.J.

1978-01-01

Two types of mechanical presses are being tested from the remote operation and remote maintenance aspects. Results will be used to recommend the type of press and design considerations required for operation in a remotely operated and maintained process line

Hot pressing and lithification of gouge during the Mount St. Helens 2004-2008 eruption: insights from high temperature deformation experiments

Science.gov (United States)

Ryan, Amy G.; Russell, James K.; Heap, Michael J.

2017-04-01

and 850°C. This change in axial strain-time curves with increasing T suggests the inclusion of a second densification process, aside from mechanical compaction, at elevated T. It is our hypothesis that solid-state sintering, a process wherein crystalline particles are fused together as a result of atomic diffusion across grain boundaries (i.e., the process occurring during the industrial production of ceramics by hot (isostatic) pressing), is the dominant mechanism operating at high T and under pressure. While viscous sintering (i.e. welding) operates in many "melt-glass-rich" volcanic systems, solid-state sintering has yet to be explored as a densification mechanism operating on fine granular crystalline volcanic materials at conditions and timescales relevant to volcanic processes.

Effects of pressing temperature and initial microstructure on the equal channel angular pressing of Ti-6Al-4V alloy

International Nuclear Information System (INIS)

Ko, Y.G.; Lee, Y.H.; Jung, W.S.; Shin, D.H.; Lee, C.S.

2003-01-01

The effects of pressing temperature and initial microstructure on the equal channel angular (ECA) pressing of Ti-6Al-4V alloy were investigated in this study. The ECA pressing was carried out isothermally with route C at 500 C, 600 C and 700 C for two typical microstructures, i.e., the Widmanstaetten microstructure and the equiaxed microstructure. The results showed that ECA pressing at 600 C and 700 C was successful without producing any noticeable segment at the specimen surfaces, while a large amount of surface segments were produced at 500 C. After 1 pass pressing at 600 C, the equiaxed microstructure showed more uniform material flow at the surface than the Widmanstaetten microstructure. However, this microstructural influence was diminished with increase of the number of the ECA pressing. A flow-localization parameter that quantifies the flow non-uniform tendency in case of flow softening materials was used to explain the different results in each microstructure. (orig.)

Idealized Compression Ratio for a Screw Briquetting Press

Directory of Open Access Journals (Sweden)

Peter Biath

2012-01-01

Full Text Available This paper deals with issues in determining the ideal compression ratio for a screw briquetting press. First, the principles of operation and a basic description of the main parts of a screw briquetting press are introduced. The next section describes the pressing space by means of 3D software. The pressing space was created using a Boolean subtract function. The final section of the paper measures the partial volumes of the pressing chamber in CATIA V5 by function of measuring. The measured values are substituted into the formula for the compression ratio, and the resulting evaluations are presented in the diagram in the conclusion of this paper.

Teach yourself visually complete WordPress

CERN Document Server

Majure, Janet

2013-01-01

Take your WordPress skills to the next level with these tips, tricks, and tasks Congratulations on getting your blog up and running with WordPress! Now are you ready to take it to the next level? Teach Yourself VISUALLY Complete WordPress takes you beyond the blogging basics with expanded tips, tricks, and techniques with clear, step-by-step instructions accompanied by screen shots. This visual book shows you how to incorporate forums, use RSS, obtain and review analytics, work with tools like Google AdSense, and much more.Shows you how to use mobile tools to edit a

A new approach for helium backfilling and leak testing seal-welded capsules in a hot cell

International Nuclear Information System (INIS)

Strasslsund, E.K.; Berger, D.N.

1992-05-01

Gamma irradiation sources containing radioactive 137 Cesium Chloride are being produced at the US Department of Energy's Hanford Site as part of a Westinghouse Hanford company/Pacific Northwest Laboratory cooperative program. New equipment was developed to leak test the double-encapsulated sources in a hot cell. The equipment, which includes a helium backfill chamber and end cap press , a vacuum chamber, and a helium mass spectrometer, has provided technicians with the capability to detect leaks in sealed sources as small as 1. 0x10 -7 atm cm 3 /S helium

The positive effect of hot isostatic pressing on improving the anisotropies of bending and impact properties in selective laser melted Ti-6Al-4V alloy

Energy Technology Data Exchange (ETDEWEB)

Wu, Ming-Wei, E-mail: mwwu@ntut.edu.tw; Lai, Pang-Hsin

2016-03-21

Selective laser melting (SLM) is a versatile additive manufacturing process for fabricating solid or porous metallic materials with complicated three-dimensional shapes. SLM Ti alloys, particularly Ti-6Al-4V, and other alloys have been manufactured and analyzed in numerous studies. However, the high anisotropy of the microstructures and inconsistent mechanical properties of SLM materials have been extensively reported, and these disadvantages could prohibit its widespread use. To clarify how to alleviate the anisotropic behaviors of SLM materials, the main objective of this study was to evaluate the influences of hot isostatic pressing (HIP) on the microstructure, densification, bending strength, impact toughness, and fracture behavior of the as-built Ti-6Al-4V alloy. The results showed that the vertical and horizontal building directions obviously affect the bending and impact properties of as-built alloys. The transverse rupture strength (TRS) and impact energy of the horizontally-built alloy were respectively found to be 48% and 100% higher than those of the vertically-built one. In the vertically-built alloy, disc-shaped building defects, identified by X-ray computed tomography (CT) and microscopy, obviously reduce the effective load-bearing cross-section and deteriorate the bending and impact performances. After HIP at 1000 °C/150 MPa, the α′-martensite structure in the as-built alloy is transformed into an α+β lamellar one, and the disc-shaped building defects are evidently eliminated. As a result, the impact energies of as-built vertical and horizontal specimens are improved by 28 J (560%) and 19 J (190%), respectively, and the TRS of the as-built vertical alloy is raised by 550 MPa (37%). Consequently, the discrepancies in TRS and impact energy between the HIPed vertical and horizontal specimens are merely 3% and 14%, respectively, and the anisotropic behaviors of the SLM Ti-6Al-4V alloy are thus substantially lessened.

The positive effect of hot isostatic pressing on improving the anisotropies of bending and impact properties in selective laser melted Ti-6Al-4V alloy

International Nuclear Information System (INIS)

Wu, Ming-Wei; Lai, Pang-Hsin

2016-01-01

Selective laser melting (SLM) is a versatile additive manufacturing process for fabricating solid or porous metallic materials with complicated three-dimensional shapes. SLM Ti alloys, particularly Ti-6Al-4V, and other alloys have been manufactured and analyzed in numerous studies. However, the high anisotropy of the microstructures and inconsistent mechanical properties of SLM materials have been extensively reported, and these disadvantages could prohibit its widespread use. To clarify how to alleviate the anisotropic behaviors of SLM materials, the main objective of this study was to evaluate the influences of hot isostatic pressing (HIP) on the microstructure, densification, bending strength, impact toughness, and fracture behavior of the as-built Ti-6Al-4V alloy. The results showed that the vertical and horizontal building directions obviously affect the bending and impact properties of as-built alloys. The transverse rupture strength (TRS) and impact energy of the horizontally-built alloy were respectively found to be 48% and 100% higher than those of the vertically-built one. In the vertically-built alloy, disc-shaped building defects, identified by X-ray computed tomography (CT) and microscopy, obviously reduce the effective load-bearing cross-section and deteriorate the bending and impact performances. After HIP at 1000 °C/150 MPa, the α′-martensite structure in the as-built alloy is transformed into an α+β lamellar one, and the disc-shaped building defects are evidently eliminated. As a result, the impact energies of as-built vertical and horizontal specimens are improved by 28 J (560%) and 19 J (190%), respectively, and the TRS of the as-built vertical alloy is raised by 550 MPa (37%). Consequently, the discrepancies in TRS and impact energy between the HIPed vertical and horizontal specimens are merely 3% and 14%, respectively, and the anisotropic behaviors of the SLM Ti-6Al-4V alloy are thus substantially lessened.

Probing binding hot spots at protein-RNA recognition sites.

Science.gov (United States)

Barik, Amita; Nithin, Chandran; Karampudi, Naga Bhushana Rao; Mukherjee, Sunandan; Bahadur, Ranjit Prasad

2016-01-29

We use evolutionary conservation derived from structure alignment of polypeptide sequences along with structural and physicochemical attributes of protein-RNA interfaces to probe the binding hot spots at protein-RNA recognition sites. We find that the degree of conservation varies across the RNA binding proteins; some evolve rapidly compared to others. Additionally, irrespective of the structural class of the complexes, residues at the RNA binding sites are evolutionary better conserved than those at the solvent exposed surfaces. For recognitions involving duplex RNA, residues interacting with the major groove are better conserved than those interacting with the minor groove. We identify multi-interface residues participating simultaneously in protein-protein and protein-RNA interfaces in complexes where more than one polypeptide is involved in RNA recognition, and show that they are better conserved compared to any other RNA binding residues. We find that the residues at water preservation site are better conserved than those at hydrated or at dehydrated sites. Finally, we develop a Random Forests model using structural and physicochemical attributes for predicting binding hot spots. The model accurately predicts 80% of the instances of experimental ΔΔG values in a particular class, and provides a stepping-stone towards the engineering of protein-RNA recognition sites with desired affinity. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Hot Surface Ignition

OpenAIRE

Tursyn, Yerbatyr; Goyal, Vikrant; Benhidjeb-Carayon, Alicia; Simmons, Richard; Meyer, Scott; Gore, Jay P.

2015-01-01

Undesirable hot surface ignition of flammable liquids is one of the hazards in ground and air transportation vehicles, which primarily occurs in the engine compartment. In order to evaluate the safety and sustainability of candidate replacement fuels with respect to hot surface ignition, a baseline low lead fuel (Avgas 100 LL) and four experimental unleaded aviation fuels recommended for reciprocating aviation engines were considered. In addition, hot surface ignition properties of the gas tu...

Disaggregating Hot Water Use and Predicting Hot Water Waste in Five Test Homes

Energy Technology Data Exchange (ETDEWEB)

Henderson, H.; Wade, J.

2014-04-01

While it is important to make the equipment (or 'plant') in a residential hot water system more efficient, the hot water distribution system also affects overall system performance and energy use. Energy wasted in heating water that is not used is estimated to be on the order of 10 to 30 percent of total domestic hot water (DHW) energy use. This field monitoring project installed temperature sensors on the distribution piping (on trunks and near fixtures) and programmed a data logger to collect data at 5 second intervals whenever there was a hot water draw. This data was used to assign hot water draws to specific end uses in the home as well as to determine the portion of each hot water that was deemed useful (i.e., above a temperature threshold at the fixture). Five houses near Syracuse NY were monitored. Overall, the procedures to assign water draws to each end use were able to successfully assign about 50% of the water draws, but these assigned draws accounted for about 95% of the total hot water use in each home. The amount of hot water deemed as useful ranged from low of 75% at one house to a high of 91% in another. At three of the houses, new water heaters and distribution improvements were implemented during the monitoring period and the impact of these improvements on hot water use and delivery efficiency were evaluated.

Disaggregating Hot Water Use and Predicting Hot Water Waste in Five Test Homes

Energy Technology Data Exchange (ETDEWEB)

Henderson, Hugh [ARIES Collaborative, New York, NY (United States); Wade, Jeremy [ARIES Collaborative, New York, NY (United States)

2014-04-01

While it is important to make the equipment (or "plant") in a residential hot water system more efficient, the hot water distribution system also affects overall system performance and energy use. Energy wasted in heating water that is not used is estimated to be on the order of 10%-30% of total domestic hot water (DHW) energy use. This field monitoring project installed temperature sensors on the distribution piping (on trunks and near fixtures) in five houses near Syracuse, NY, and programmed a data logger to collect data at 5 second intervals whenever there was a hot water draw. This data was used to assign hot water draws to specific end uses in the home as well as to determine the portion of each hot water that was deemed useful (i.e., above a temperature threshold at the fixture). Overall, the procedures to assign water draws to each end use were able to successfully assign about 50% of the water draws, but these assigned draws accounted for about 95% of the total hot water use in each home. The amount of hot water deemed as useful ranged from low of 75% at one house to a high of 91% in another. At three of the houses, new water heaters and distribution improvements were implemented during the monitoring period and the impact of these improvements on hot water use and delivery efficiency were evaluated.

Relationship between hot spot residues and ligand binding hot spots in protein-protein interfaces.

Science.gov (United States)

Zerbe, Brandon S; Hall, David R; Vajda, Sandor; Whitty, Adrian; Kozakov, Dima

2012-08-27

In the context of protein-protein interactions, the term "hot spot" refers to a residue or cluster of residues that makes a major contribution to the binding free energy, as determined by alanine scanning mutagenesis. In contrast, in pharmaceutical research, a hot spot is a site on a target protein that has high propensity for ligand binding and hence is potentially important for drug discovery. Here we examine the relationship between these two hot spot concepts by comparing alanine scanning data for a set of 15 proteins with results from mapping the protein surfaces for sites that can bind fragment-sized small molecules. We find the two types of hot spots are largely complementary; the residues protruding into hot spot regions identified by computational mapping or experimental fragment screening are almost always themselves hot spot residues as defined by alanine scanning experiments. Conversely, a residue that is found by alanine scanning to contribute little to binding rarely interacts with hot spot regions on the partner protein identified by fragment mapping. In spite of the strong correlation between the two hot spot concepts, they fundamentally differ, however. In particular, while identification of a hot spot by alanine scanning establishes the potential to generate substantial interaction energy with a binding partner, there are additional topological requirements to be a hot spot for small molecule binding. Hence, only a minority of hot spots identified by alanine scanning represent sites that are potentially useful for small inhibitor binding, and it is this subset that is identified by experimental or computational fragment screening.

WordPress web design for dummies

CERN Document Server

Sabin-Wilson, Lisa

2013-01-01

Updated, full-color guide to creating dynamic websites with WordPress 3.6 In this updated new edition, bestselling For Dummies author and WordPress expert Lisa Sabin-Wilson makes it easy for anyone with a basic knowledge of the WordPress software to create a custom site using complementary technologies such as CSS, HTML, PHP, and MySQL. You'll not only get up to speed on essential tools and technologies and further advance your own design skills, this book also gives you pages of great case studies, so you can see just how other companies and individuals are creating compelling, customized, a

Energy flux of hot atoms

International Nuclear Information System (INIS)

Wotzak, G.P.; Kostin, M.D.

1976-01-01

The process in which hot atoms collide with thermal atoms of a gas, transfer kinetic energy to them, and produce additional hot atoms is investigated. A stochastic method is used to obtain numerical results for the spatial and time dependent energy flux of hot atoms in a gas. The results indicate that in hot atom systems a front followed by an intense energy flux of hot atoms may develop

Searching for a Free Press in Indian Country.

Science.gov (United States)

Benton, Sherrole

1994-01-01

Describes the tribally controlled media's efforts to provide a form of checks and balances against the tribal council on behalf of the tribal community. Examines the issue of freedom of the tribal press, suggesting that tribal council's control of press's operating funds may limit press freedom. (MAB)

Graphic Arts: Book Three. The Press and Related Processes.

Science.gov (United States)

Farajollahi, Karim; And Others

The third of a three-volume set of instructional materials for a graphic arts course, this manual consists of nine instructional units dealing with presses and related processes. Covered in the units are basic press fundamentals, offset press systems, offset press operating procedures, offset inks and dampening chemistry, preventive maintenance…

Modelling Hot Air Balloons.

Science.gov (United States)

Brimicombe, M. W.

1991-01-01

A macroscopic way of modeling hot air balloons using a Newtonian approach is presented. Misleading examples using a car tire and the concept of hot air rising are discussed. Pressure gradient changes in the atmosphere are used to explain how hot air balloons work. (KR)

The Mediated Amplification of a Crisis: Communicating the A/H1N1 Pandemic in Press Releases and Press Coverage in Europe.

Science.gov (United States)

Rossmann, Constanze; Meyer, Lisa; Schulz, Peter J

2018-02-01

In the aftermath of the A/H1N1 pandemic, health authorities were criticized for failures in crisis communication efforts, and the media were accused of amplifying the pandemic. Considering these criticisms, A/H1N1 provides a suitable case for examining risk amplification processes that may occur in the transfer of information from press releases to print news media during a health crisis. We integrated the social amplification of risk framework with theories of news decisions (news values, framing) in an attempt to contribute to existing research both theoretically and empirically. We conducted a quantitative content analysis of press releases disseminated by health and governmental authorities, as well as the quality and tabloid press in 10 European countries between March 2009 and March 2011. Altogether 243 press releases, 1,243 quality press articles, and 834 tabloid press articles were coded. Consistent with research on news values and framing the results suggest that quality and tabloid papers alike amplified A/H1N1 risks by emphasizing conflict and damage, presenting information in a more dramatized way, and using risk-amplifying frames to a greater extent and risk-attenuating frames to a lesser extent than press releases. To some extent, the quality and tabloid press differed in how risk information was presented. While tabloid press articles seemed to follow the leading quality press with regards to content and framing of health crisis coverage, they exhibited a stronger emphasis on drama and emotion in the way they presented information. © 2017 Society for Risk Analysis.

OAS :: Press Releases

Science.gov (United States)

subscriptions Videos Photos Live Webcast Social Media Facebook @oasofficial Facebook Twitter @oas_official Social Media Facebook Twitter Newsletters Press and Communications Department Contact us at: +1 (202) 370 Rights Actions against Corruption C Children Civil Registry Civil Society Contact Us Culture Cyber

DSS / Press Room

Science.gov (United States)

Defense Security Service, U.S. Department of Defense Site Map | A-Z Index | Facebook | Twitter Locations Press Room Organizational Structure Careers at DSS Doing Business with DSS Frequently Asked Classification System (NCCS) National Industrial Security System (NISS) ODAA Business Management System (OBMS

PRESS FREEDOM IN SINGAPORE AND MALAYSIA: DEFAMATION

OpenAIRE

Georgia Kate Chapman

2015-01-01

This paper focuses on the arguments around restriction on freedom of the press in the Strong States of Singapore and Malaysia. It assesses the presence of constraints on press freedoms in democratic western countries imposed by corporation rather than state and the similar effects that these constraints may have on bias present in publicly accessible news reporting. It argues that independence of the press does not just require protection from legal and executive regulation, but also protecti...

Software Simulation of Hot Tearing

DEFF Research Database (Denmark)

Andersen, S.; Hansen, P.N.; Hattel, Jesper Henri

1999-01-01

The brittleness of a solidifying alloy in a temperature range near the solidus temperature has been recognised since the fifties as the mechanism responsible for hot tearing. Due to this brittlenes, the metal will crack under even small amounts of strain in that temperature range. We see these hot...... tears in castings close to hot centres, where the level of strain is often too high.Although the hot tearing mechanism is well understood, until now it has been difficult to do much to reduce the hot tearing tendency in a casting. In the seventies, good hot tearing criteria were developed by considering...... the solidification rate and the strain rate of the hot tear prone areas. But, until recently it was only possible to simulate the solidification rate, so that the criteria could not be used effectively.Today, with new software developments, it is possible to also simulate the strain rate in the hot tear prone areas...

Novel process chain for hot metal gas forming of ferritic stainless steel 1.4509

Science.gov (United States)

Mosel, André; Lambarri, Jon; Degenkolb, Lars; Reuther, Franz; Hinojo, José Luis; Rößiger, Jörg; Eurich, Egbert; Albert, André; Landgrebe, Dirk; Wenzel, Holger

2018-05-01

Exhaust gas components of automobiles are often produced in ferritic stainless steel 1.4509 due to the low thermal expansion coefficient and the low material price. Until now, components of the stainless steel with complex geometries have been produced in series by means of multi-stage hydroforming at room temperature with intermediate annealing operations. The application of a single-stage hot-forming process, also referred to as hot metal gas forming (HMGF), offers great potential to significantly reduce the production costs of such components. The article describes a novel process chain for the HMGF process. Therefore the tube is heated in two steps. After pre-heating of the semi-finished product outside the press, the tube is heated up to forming start temperature by means of a tool-integrated conductive heating before forming. For the tube of a demonstrator geometry, a simulation model for the conduction heating was set up. In addition to the tool development for this process, experimental results are also described for the production of the demonstrator geometry.

Hot tub folliculitis

Science.gov (United States)

... survives in hot tubs, especially tubs made of wood. Symptoms The first symptom of hot tub folliculitis ... may help prevent the problem. Images Hair follicle anatomy References D'Agata E. Pseudomonas aeruginosa and other ...

Teenagers as Victims in the Press

Science.gov (United States)

Andersson, Gunvor; Lundstrom, Tommy

2007-01-01

Research into press reporting on young people has tended to concentrate on young people as offenders. In contrast, this article focuses on press coverage of teenagers as victims. Reports in two Swedish newspapers (a morning broadsheet and an evening tabloid) were studied over a period of four months and subjected to a qualitative analysis of…

Hot conditioning equipment conceptual design report

International Nuclear Information System (INIS)

Bradshaw, F.W.

1996-01-01

This report documents the conceptual design of the Hot Conditioning System Equipment. The Hot conditioning System will consist of two separate designs: the Hot Conditioning System Equipment; and the Hot Conditioning System Annex. The Hot Conditioning System Equipment Design includes the equipment such as ovens, vacuum pumps, inert gas delivery systems, etc.necessary to condition spent nuclear fuel currently in storage in the K Basins of the Hanford Site. The Hot Conditioning System Annex consists of the facility of house the Hot Conditioning System. The Hot Conditioning System will be housed in an annex to the Canister Storage Building. The Hot Conditioning System will consist of pits in the floor which contain ovens in which the spent nuclear will be conditioned prior to interim storage

Hot conditioning equipment conceptual design report

Energy Technology Data Exchange (ETDEWEB)

Bradshaw, F.W., Westinghouse Hanford

1996-08-06

This report documents the conceptual design of the Hot Conditioning System Equipment. The Hot conditioning System will consist of two separate designs: the Hot Conditioning System Equipment; and the Hot Conditioning System Annex. The Hot Conditioning System Equipment Design includes the equipment such as ovens, vacuum pumps, inert gas delivery systems, etc.necessary to condition spent nuclear fuel currently in storage in the K Basins of the Hanford Site. The Hot Conditioning System Annex consists of the facility of house the Hot Conditioning System. The Hot Conditioning System will be housed in an annex to the Canister Storage Building. The Hot Conditioning System will consist of pits in the floor which contain ovens in which the spent nuclear will be conditioned prior to interim storage.

PM-materials for hot working tools; PM-Werkstoffe fuer warmgehende Werkzeuge

Energy Technology Data Exchange (ETDEWEB)

Berns, H.; Broeckmann, C.; Theisen, W. [Bochum Univ. (Germany). Fakultaet fuer Maschinenbau; Wewers, B.

2001-05-01

Tools and wear parts for compacting tools are subjected to high abrasive wear and mechanical loading at elevated temperatures. MMC's based in iron- or nickel with hard particles are developed and investigated. The materials were manufactured from powders by hot isostatic pressing (HIP) and subsequently heat treated. Diffusion between hard phases and metal matrix brings about certain micro structures which were tested with respect to the resistance against sliding abrasion at room and elevated temperatures. Three-point bending tests and thermal cycling of the material was utilized to characterise the mechanical behaviour. Based on this results a toolkit for a roller press for briquetting was produced and brought into application. (orig.) [German] Werkzeuge und Verschleissteile fuer die Verarbeitung von mineralischen Guetern bei erhoehter Temperatur unterliegen sowohl hohem abrasivem Verschleiss als auch hohen mechanischen Lasten. Es werden hartphasenhaltige Verbundwerkstoffe auf Eisen- und Nickelbasis entwickelt und untersucht. Die Fertigung dieser MMC's erfolgt durch heiss isostatisches Pressen (HIP) und anschliessende Waermebehandlung. Durch Diffusion zwischen Hartphasen und Metallmatrix entstehen Gefuege, die bezueglich ihres Widerstandes gegen Abrasivverschleiss bei Raumtemperatur und gegen Korngleitverschliess bei erhoehter Temperatur geprueft werden. Zur Charakterisierung der mechanischen Eigeschaften werden Dreipunktbiegeversuche und thermsiche Ermuedungsversuche durchgefuehrt. Die gewonnenen Erkenntnisse werden genutzt, um einen Werkzeugsatz fuer eine Brikettierpresse herzustellen und in Einsatz zu bringen. (orig.)

The small academic press in the land of giants

Directory of Open Access Journals (Sweden)

Frances Pinter

2015-11-01

Full Text Available Mergers and acquisitions, for example the merger of Macmillan Science and Education with Springer Science+Business Media, might suggest that large is the future for academic publishing.  It might seem that giant players will dominate the future of scholarly publishing, but, at the same time, this year has seen the launch of UCL Press, the University’s in-house publishing arm. Goldsmiths, University of London, has also announced it is preparing to launch Goldsmiths Press, a new university press built on digital-first publishing, especially around unconventional projects traditionally excluded by publishers. Some of the more established university presses also seem to be increasing their scope. For example, Stanford University Press launched a new trade imprint and Manchester University Press has announced it has acquired forward titles from Bloomsbury Publishing.  'Insights 'asked two experts if there really is scope for the small academic press in the modern scholarly publishing environment. Frances Pinter has provided the perspective of the small university press. She is realistic about the challenges small academic publishers face, but concludes that there is space and opportunity for them to coexist with the giants. Michael Magoulias is equally realistic about the challenges of small, but sees the university press as a necessary, not to say, vital, alternative to commercial publishing.

Elbow joint fatigue and bench-press training.

Science.gov (United States)

Huang, Yen-Po; Chou, You-Li; Chen, Feng-Chun; Wang, Rong-Tyai; Huang, Ming-Jer; Chou, Paul Pei-Hsi

2014-01-01

Bench-press exercises are among the most common form of training exercise for the upper extremity because they yield a notable improvement in both muscle strength and muscle endurance. The literature contains various investigations into the effects of different bench-press positions on the degree of muscle activation. However, the effects of fatigue on the muscular performance and kinetics of the elbow joint are not understood fully. To investigate the effects of fatigue on the kinetics and myodynamic performance of the elbow joint in bench-press training. Controlled laboratory study. Motion research laboratory. A total of 18 physically healthy male students (age = 19.6 ± 0.8 years, height = 168.7 ± 5.5 cm, mass = 69.6 ± 8.6 kg) participated in the investigation. All participants were right-hand dominant, and none had a history of upper extremity injuries or disorders. Participants performed bench-press training until fatigued. Maximal possible number of repetitions, cycle time, myodynamic decline rate, elbow-joint force, and elbow-joint moment. We observed a difference in cycle time in the initial (2.1 ± 0.42 seconds) and fatigue (2.58 ± 0.46 seconds) stages of the bench-press exercise (P = .04). As the participants fatigued, we observed an increase in the medial-lateral force (P = .03) and internal-external moment (P ≤ .04) acting on the elbow joint. Moreover, a reduction in the elbow muscle strength was observed in the elbow extension-flexion (P ≤ .003) and forearm supination-pronation (P ≤ .001) conditions. The results suggest that performing bench-press exercises to the point of fatigue increases elbow-joint loading and may further increase the risk of injury. Therefore, when clinicians design bench-press exercise regimens for general athletic training, muscle strengthening, or physical rehabilitation, they should control carefully the maximal number of repetitions.

WESF hot cells waste minimization criteria hot cells window seals evaluation

International Nuclear Information System (INIS)

Walterskirchen, K.M.

1997-01-01

WESF will decouple from B Plant in the near future. WESF is attempting to minimize the contaminated solid waste in their hot cells and utilize B Plant to receive the waste before decoupling. WESF wishes to determine the minimum amount of contaminated waste that must be removed in order to allow minimum maintenance of the hot cells when they are placed in ''laid-up'' configuration. The remaining waste should not cause unacceptable window seal deterioration for the remaining life of the hot cells. This report investigates and analyzes the seal conditions and hot cell history and concludes that WESF should remove existing point sources, replace cerium window seals in F-Cell and refurbish all leaded windows (except for A-Cell). Work should be accomplished as soon as possible and at least within the next three years

Internet Marketing with WordPress

CERN Document Server

Mercer, David

2011-01-01

The book's accompanying Interactive learning environment on siteprebuilder.com gives you an online place to enhance and extend your practical experience through exercises, consolidate your learning and theoretical knowledge with marked quizzes, interaction with your WordPress marketing community, and fun and exciting extras such as challenges and competitions. This book is for people already using WordPress, who want more visitors, better visitors, and to convert more of them into paying customers. No prior marketing experience is required, although a basic understanding of either hosted or se

Hot impact densification (HID) - a new method of producing ceramic nuclear fuel pellets with tight dimensional tolerances

International Nuclear Information System (INIS)

Hrovat, M.; Rachor, L.; Muehling, G.; Vollath, D.; Zimmermann, H.

1984-01-01

The hot impact densification (HID) is a new powerful method for producing ceramic fuel pellets for nuclear reactors. Green ceramic bodies are directly processed to pellets by high speed shaping in the plastic temperature region of ceramic material. Opposed to the well established press sintering procedure it can be heated, densified, and cooled by orders of magnitude faster. Therefore, at high throughputs, small equipment dimensions become possible. The fuel pellets produced meet all requirements, particular the dimensional tolerances achieved are very closed, consequently circular grinding is omitted. Furthermore, the relatively high temperature level of the impact pressing favors the mixed crystal formation of uranium and plutonium oxide. This improves the solubility of the fuel in nitric acid, an essential point at reprocessing. A prototype facility is designed so that automatic fabrication in continuous operation will be possible. The target working cycle for a fuel pellet is in the range of some seconds. (orig.)

10 CFR 431.102 - Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water...

Science.gov (United States)

2010-01-01

... supply boilers, and unfired hot water storage tanks. 431.102 Section 431.102 Energy DEPARTMENT OF ENERGY... Water Heaters, Hot Water Supply Boilers and Unfired Hot Water Storage Tanks § 431.102 Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water storage tanks. The...

Influence of the "Slingshot" bench press training aid on bench press kinematics and neuromuscular activity in competitive powerlifters.

Science.gov (United States)

Dugdale, James H; Hunter, Angus; Di Virgilio, Thomas; Macgregor, Lewis J; Hamilton, D Lee

2017-02-13

This study examined the acute effects of the 'Slingshot' on bench-press performance, prime-mover surface electromyographic (sEMG) amplitude, and barbell velocity during maximal and submaximal bench-pressing in competitive male powerlifters. Fifteen male powerlifters (mean ± SD age: 27.05 ± 5.94 years; mass: 94.15kg; 1RM bench-press: 139.7 ± 16.79kg) participated in the study. Bench-press strength, average barbell velocity, and sEMG amplitude of the prime mover muscles (triceps brachii, pectoralis major and anterior deltoid) were measured during two conditions; 'Raw' (without use of any assistance) and 'Slingshot' [using the 'Slingshot' to perform both the weight achieved during 'Raw' 1RM testing (Raw max/SS), and absolute 1RM using the 'Slingshot' (SS)]. The results showed that the 'Slingshot' significantly increased bench press 1RM performance by a mean ± SD of 20.67kg ± 3.4kg. Barbell velocity and stick point analysis indicate that this improvement is likely driven by an increase in peak and pre-stick barbell velocity as triceps RMS was lower throughout all rep max phases with the 'Slingshot'. The 'Slingshot' also caused reductions in RMS, specifically of the triceps at all rep ranges but barbell velocity was better maintained in the last reps of all sets. These data indicate that the 'Slingshot' specifically de-loaded the triceps muscle throughout all rep ranges and provide assistance to maintaining barbell velocity under fatigue during later repetitions of multiple-repetition sets. The 'Slingshot' training aid could therefore be used in de-load phases of bench press training or as an over-reaching and velocity training aid.

The kappa Distribution as Tool in Investigating Hot Plasmas in the Magnetospheres of Outer Planets

Science.gov (United States)

Krimigis, S. M.; Carbary, J. F.

2014-12-01

The first use of a Maxwellian distribution with a high-energy tail (a κ-function) was made by Olbert (1968) and applied by Vasyliunas (1968) in analyzing electron data. The k-function combines aspects of both Maxwellian and power law forms to provide a reasonably complete description of particle density, temperature, pressure and convection velocity, all of which are key parameters of magnetospheric physics. Krimigis et al (1979) used it to describe flowing plasma ions in Jupiter's magnetosphere measured by Voyager 1, and obtained temperatures in the range of 20 to 35 keV. Sarris et al (1981) used the κ-function to describe plasmas in Earth's distant plasma sheet. The κ-function, in various formulations and names (e. g., γ-thermal distribution, Krimigis and Roelof, 1983) has been used routinely to parametrize hot, flowing plasmas in the magnetospheres of the outer planets, with typical kT ~ 10 to 50 keV. Using angular measurements, it has been possible to obtain pitch angle distributions and convective flow directions in sufficient detail for computations of temperatures and densities of hot particle pressures. These 'hot' pressures typically dominate the cold plasma pressures in the high beta (β > 1) magnetospheres of Jupiter and Saturn, but are of less importance in the relatively empty (β Cambridge University Press, New York, 1983

Denmark, Democracy and the Free Press

DEFF Research Database (Denmark)

Breiting, Søren

2006-01-01

What's important to Danish people in Denmark and in the world - most will argue for the importance of a free critical press, solidarity with people who need help and a peaceful world.......What's important to Danish people in Denmark and in the world - most will argue for the importance of a free critical press, solidarity with people who need help and a peaceful world....

Hot springs in Hokuriku District

Energy Technology Data Exchange (ETDEWEB)

Sato, K. (Hot Springs Research Center, Japan)

1971-01-01

In the Hokuriku district including Toyama, Ishikawa, and Fukui Prefectures, hot springs of more than 25/sup 0/C were investigated. In the Toyama Prefecture, there are 14 hot springs which are located in an area from the Kurobe River to the Tateyama volcano and in the mountainous area in the southwest. In Ishikawa Prefecture there are 16 hot springs scattered in Hakusan and its vicinity, the Kaga mountains, and in the Noto peninsula. In northern Fukui Prefecture there are seven hot springs. The hot springs in Shirakawa in Gifu Prefecture are characterized as acid springs producing exhalations and H/sub 2/S. These are attributed to the Quaternary volcanoes. The hot springs of Wakura, Katayamazu, and Awara in Ishikawa Prefecture are characterized by a high Cl content which is related to Tertiary andesite. The hot springs of Daishoji, Yamanaka, Yamashiro, Kuritsu, Tatsunokuchi, Yuwaku, and Yunotani are characterized by a low HCO/sub 3/ content. The Ca and SO/sub 4/ content decreases from east to west, and the Na and Cl content increases from west to east. These fluctuations are related to the Tertiary tuff and rhyolite. The hot springs of Kuronagi, Kinshu, and Babadani, located along the Kurobe River are characterized by low levels of dissolved components and high CO/sub 2/ and HCO/sub 3/ content. These trends are related to late Paleozoic granite. Hot springs resources are considered to be connected to geothermal resources. Ten tables, graphs, and maps are provided.

The Liberal Struggle for Press Freedom

DEFF Research Database (Denmark)

Mogensen, Kirsten

In this paper, the public debate following the re-ligion-motivated assassination of Dutch filmmaker Theo van Gogh in November 2004 is examined. The paper aims at describ-ing religious as well as secular positions in the Danish debate about freedom of speech and press in relation to religious issues....... Historically, the concept of press freedom was linked to a fight for religious freedom in London, as described by Siebert....

1979: The Campus Student Press in America.

Science.gov (United States)

Ingelhart, Louis E.

1979-01-01

Discusses a number of topics involving the campus press, including the independence of campus publications, censorship issues, the relationship between the student press and the college administrator, the financing of student newspapers, yearbook production and financing, probable future student publications trends, and the need for appropriate…

Jatropha press cake as organic fertilizer in lettuce cultivation

Directory of Open Access Journals (Sweden)

José R. Mantovani

Full Text Available ABSTRACT In biodiesel production, vegetable press cake is obtained as waste, and a suitable destination for jatropha press cake would be the use in agriculture as organic fertilizer. This study aimed to evaluate the effect of jatropha press cake on soil fertility attributes and on lettuce production and accumulation of nutrients in the shoots. The experiment was conducted in pots in a greenhouse, in a randomized block design with eight treatments and five replicates. The treatments consisted of doses of jatropha press cake equivalent to 0, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 and 32.0 t ha-1. Portions of 5.5 dm3 of soil received limestone, phosphate fertilizer and the doses of jatropha press cake, and remained incubated for 30 days. After incubation, soil samples were collected, each pot received one lettuce seedling and the experiment was carried out for 45 days. The organic fertilization with jatropha press cake increased the contents of nutrients in the soil, especially K+, but caused increment in soil acidity and electrical conductivity. The use of jatropha press cake as organic fertilizer decreased lettuce production and accumulation of nutrients in the shoots.

Study of Servo Press with a Flywheel

Science.gov (United States)

Tso, Pei-Lum; Li, Cheng-Ho

The servo press with a flywheel is able to provide flexible motions with energy-saving merit, but its true potential has not been thoroughly studied and verified. In this paper, such the “hybrid-driven” servo press is focused on, and the stamping capacity and the energy distribution between the flywheel and the servomotor are investigated. The capacity is derived based on the principle of energy conservation, and a method of using a capacity percentage plane for evaluation is proposed. A case study is included to illustrate and interpret that the stamping capacity is highly dependent on the programmed punch motions, thus the capacity prediction is always necessary while applying this kind of servo press. The energy distribution is validated by blanking experiments, and the results indicate that the servomotor needs only to provide 15% to the flywheel torque, 12% of the total stamping energy. This validates that the servomotor power is significantly saved in comparison with conventional servo presses.

Distal clavicular osteolysis in adults: association with bench pressing intensity

International Nuclear Information System (INIS)

Nevalainen, Mika T.; Morrison, William B.; Zoga, Adam C.; Roedl, Johannes B.; Ciccotti, Michael G.

2016-01-01

To investigate the association between distal clavicular osteolysis (DCO) and bench pressing intensity. From a retrospective review of MRI shoulder reports of individuals between 20 and 40 years of age, 262 male patients with DCO and 227 age-matched male patients without DCO were selected. All patients had completed a bench pressing questionnaire. The patients' bench pressing frequency (times per week), duration (years of bench pressing), bench pressing weight (maximum bench pressing weight with one repetition = 1RM) and the ratio of bench pressing weight to body weight were compared between both groups using Chi-square and Mann-Whitney tests. The results showed that 56 % (146/262) of patients with DCO were high-intensity bench pressers (1RM more than 1.5 times the body weight) compared to 6 % (14/227) in patients without DCO. High-intensity bench pressing was a risk factor for DCO (OR = 19; 95 %CI = 11-35; p 1 x /week) and duration (>5 years) of bench pressing were risk factors. In bench pressers who suffered from DCO, the mean 1RM was 283 lbs (±SD 57) compared to 209 lbs (±SD 60) in bench pressers not affected by DCO (p < 0.001, Mann-Whitney). High-intensity, but not low-intensity bench pressing is a risk factor for DCO. (orig.)

Resident-performed Ex-PRESS shunt implantation versus trabeculectomy.

Science.gov (United States)

Seider, Michael I; Rofagha, Soraya; Lin, Shan C; Stamper, Robert L

2012-09-01

To compare outcomes between resident-performed trabeculectomy and Ex-PRESS shunt implantation. A consecutive cohort of 36 Ex-PRESS shunt implantations and 57 trabeculectomies (1 eye/patient) performed by resident surgeons in their third year of ophthalmic training at the University of California, San Francisco and at the San Francisco Veterans Administration Hospital, under the supervision of a single glaucoma fellowship-trained surgeon were included in this study. Eyes with PRESS shunt groups at all follow-up points. On average, the Ex-PRESS shunt group required significantly less ocular antihypertensive medication to control IOP at 3 months postoperative (P=0.01), but no difference was found at 6 months or 1 year (all, P≥0.28). A larger proportion of Ex-PRESS shunt patients had good IOP control without medication at 3 (P=0.057) and 6 months (P=0.076) postoperatively. No difference was found in the rates of sight-threatening complications between groups (all, P≥0.22). In the hands of ophthalmology residents in their third year of training, the trabeculectomy and Ex-PRESS shunt implantation procedures perform comparably in terms of postoperative IOP control, reduction in patient dependence on ocular antihypertensive medications, and risk of complication in our population.

WordPress 24-hour trainer

CERN Document Server

Plumley, George

2015-01-01

Create and expand feature-rich sites with no programming experience Ready to build, maintain, and expand your web site with WordPress but have no prior programming experience? WordPress 24-Hour Trainer, 3rd Edition is your book-and-video learning solution that walks you step-by-step through all the important features you will need to know. Lessons range from focused, practical everyday tasks to more advanced, creative features. Learn from an industry professional how to enter content, create pages, manage menus, utilize plug-ins, connect to social media, create membership and e-commerce site

Direct drive digital servo press with high parallel control

Science.gov (United States)

Murata, Chikara; Yabe, Jun; Endou, Junichi; Hasegawa, Kiyoshi

2013-12-01

Direct drive digital servo press has been developed as the university-industry joint research and development since 1998. On the basis of this result, 4-axes direct drive digital servo press has been developed and in the market on April of 2002. This servo press is composed of 1 slide supported by 4 ball screws and each axis has linearscale measuring the position of each axis with high accuracy less than μm order level. Each axis is controlled independently by servo motor and feedback system. This system can keep high level parallelism and high accuracy even with high eccentric load. Furthermore the 'full stroke full power' is obtained by using ball screws. Using these features, new various types of press forming and stamping have been obtained by development and production. The new stamping and forming methods are introduced and 'manufacturing' need strategy of press forming with high added value and also the future direction of press forming are also introduced.

Distal clavicular osteolysis in adults: association with bench pressing intensity

Energy Technology Data Exchange (ETDEWEB)

Nevalainen, Mika T.; Morrison, William B.; Zoga, Adam C.; Roedl, Johannes B. [Sidney Kimmel Medical College at Thomas Jefferson University, Division of Musculoskeletal Imaging and Interventions, Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA (United States); Ciccotti, Michael G. [Sidney Kimmel Medical College at Thomas Jefferson University, Division of Sports Medicine, Department of Orthopedic Surgery, Thomas Jefferson University Hospital, Rothman Institute, Philadelphia, PA (United States)

2016-11-15

To investigate the association between distal clavicular osteolysis (DCO) and bench pressing intensity. From a retrospective review of MRI shoulder reports of individuals between 20 and 40 years of age, 262 male patients with DCO and 227 age-matched male patients without DCO were selected. All patients had completed a bench pressing questionnaire. The patients' bench pressing frequency (times per week), duration (years of bench pressing), bench pressing weight (maximum bench pressing weight with one repetition = 1RM) and the ratio of bench pressing weight to body weight were compared between both groups using Chi-square and Mann-Whitney tests. The results showed that 56 % (146/262) of patients with DCO were high-intensity bench pressers (1RM more than 1.5 times the body weight) compared to 6 % (14/227) in patients without DCO. High-intensity bench pressing was a risk factor for DCO (OR = 19; 95 %CI = 11-35; p < 0.001). Low-intensity bench pressing (1RM less than 1.5 times the body weight) was not a risk factor for DCO (OR = 0.6; 95 % CI = 0.4-0.8). High frequency (>1 x /week) and duration (>5 years) of bench pressing were risk factors. In bench pressers who suffered from DCO, the mean 1RM was 283 lbs (±SD 57) compared to 209 lbs (±SD 60) in bench pressers not affected by DCO (p < 0.001, Mann-Whitney). High-intensity, but not low-intensity bench pressing is a risk factor for DCO. (orig.)

Detection of Hot Halo Gets Theory Out of Hot Water

Science.gov (United States)

2006-02-01

Scientists using NASA's Chandra X-ray Observatory have detected an extensive halo of hot gas around a quiescent spiral galaxy. This discovery is evidence that galaxies like our Milky Way are still accumulating matter from the gradual inflow of intergalactic gas. "What we are likely witnessing here is the ongoing galaxy formation process," said Kristian Pedersen of the University of Copenhagen, Denmark, and lead author of a report on the discovery. Chandra observations show that the hot halo extends more than 60,000 light years on either side of the disk of the galaxy known as NGC 5746. The detection of such a large halo alleviates a long-standing problem for the theory of galaxy formation. Spiral galaxies are thought to form from enormous clouds of intergalactic gas that collapse to form giant, spinning disks of stars and gas. Chandra X-ray Image of NGC 5746 Chandra X-ray Image of NGC 5746 One prediction of this theory is that large spiral galaxies should be immersed in halos of hot gas left over from the galaxy formation process. Hot gas has been detected around spiral galaxies in which vigorous star formation is ejecting matter from the galaxy, but until now hot halos due to infall of intergalactic matter have not been detected. "Our observations solve the mystery of the missing hot halos around spiral galaxies," said Pedersen. "The halos exist, but are so faint that an extremely sensitive telescope such as Chandra is needed to detect them." DSS Optical Image of NGC 5746 DSS Optical Image of NGC 5746 NGC 5746 is a massive spiral galaxy about a 100 million light years from Earth. Its disk of stars and gas is viewed almost edge-on. The galaxy shows no signs of unusual star formation, or energetic activity from its nuclear region, making it unlikely that the hot halo is produced by gas flowing out of the galaxy. "We targeted NGC 5746 because we thought its distance and orientation would give us the best chance to detect a hot halo caused by the infall of

Communicators take nine Virginia Press Women awards

OpenAIRE

Owczarski, Mark

2008-01-01

Three Virginia Tech communicators have won Virginia Press Women awards. The winners - Susan Trulove, research division communications manager; Clara Cox, university publications director; and Heather Riley Chadwick, College of Architecture and Urban Studies communication manager - were announced at the Virginia Press Women Annual Spring Conference in Staunton, Va.

CSR-communication in the Business Press

DEFF Research Database (Denmark)

Morsing, Mette; Langer, Roy

on a broadly encompassing and ambiguous definition of CSR. Our empirical data shows how the business press in its discourse on CSR provides no clarity on the definition of CSR in terms of a coherent motive, a dominant stakeholder or a consistent issue, but rather maintains ambiguity and imprecision about......In this paper we analyze the construction of corporate social responsibility in the business press as an act of strategic ambiguity. While corporate social responsibility (CSR) generally evokes positive associations in public opinion, this paper demonstrates that these associations are based...... is systematically maintained in the business press. We refer to this process as strategic ambiguity. The paper discusses the potential value and limitations of framing CSR in a state of strategic ambiguity in the context of the concurrent rethinking of the role of business in modern welfare societies....

Hot Gas Halos in Galaxies

Science.gov (United States)

Mulchaey, John

Most galaxy formation models predict that massive low-redshift disk galaxies are embedded in extended hot halos of externally accreted gas. Such gas appears necessary to maintain ongoing star formation in isolated spirals like the Milky Way. To explain the large population of red galaxies in rich groups and clusters, most galaxy evolution models assume that these hot gas halos are stripped completely when a galaxy enters a denser environment. This simple model has been remarkably successful at reproducing many observed properties of galaxies. Although theoretical arguments suggest hot gas halos are an important component in galaxies, we know very little about this gas from an observational standpoint. In fact, previous observations have failed to detect soft X-ray emission from such halos in disk galaxies. Furthermore, the assumption that hot gas halos are stripped completely when a galaxy enters a group or cluster has not been verified. We propose to combine proprietary and archival XMM-Newton observations of galaxies in the field, groups and clusters to study how hot gas halos are impacted by environment. Our proposed program has three components: 1) The deepest search to date for a hot gas halo in a quiescent spiral galaxy. A detection will confirm a basic tenet of disk galaxy formation models, whereas a non-detection will seriously challenge these models and impose new constraints on the growth mode and feedback history of disk galaxies. 2) A detailed study of the hot gas halos properties of field early-type galaxies. As environmental processes such as stripping are not expected to be important in the field, a study of hot gas halos in this environment will allow us to better understand how feedback and other internal processes impact hot gas halos. 3) A study of hot gas halos in the outskirts of groups and clusters. By comparing observations with our suite of simulations we can begin to understand what role the stripping of hot gas halos plays in galaxy

bbPress complete

CERN Document Server

Wynne, Rhys

2013-01-01

A concise guide, written in an easy-to-follow format.This book is aimed at ambitious website or blog owners looking to add a forum to their site quickly and easily. Basic experience in WordPress and with managing a website is expected. Knowledge of HTML and PHP will be a bonus, though it isn't necessary.

Hot flashes and sleep in women.

Science.gov (United States)

Moe, Karen E

2004-12-01

Sleep disturbances during menopause are often attributed to nocturnal hot flashes and 'sweats' associated with changing hormone patterns. This paper is a comprehensive critical review of the research on the relationship between sleep disturbance and hot flashes in women. Numerous studies have found a relationship between self-reported hot flashes and sleep complaints. However, hot flash studies using objective sleep assessment techniques such as polysomnography, actigraphy, or quantitative analysis of the sleep EEG are surprisingly scarce and have yielded somewhat mixed results. Much of this limited evidence suggests that hot flashes are associated with objectively identified sleep disruption in at least some women. At least some of the negative data may be due to methodological issues such as reliance upon problematic self-reports of nocturnal hot flashes and a lack of concurrent measures of hot flashes and sleep. The recent development of a reliable and non-intrusive method for objectively identifying hot flashes during the night should help address the need for substantial additional research in this area. Several areas of clinical relevance are described, including the effects of discontinuing combined hormone therapy (estrogen plus progesterone) or estrogen-only therapy, the possibility of hot flashes continuing for many years after menopause, and the link between hot flashes and depression.

The Hot Cell Radioactive Waste Concept of Forschungszentrum Juelich

International Nuclear Information System (INIS)

Pott, G.; Halaszovich, St.

1999-01-01

During the last 30 years extensive scientific examinations on radioactive metals,ceramics and fuel elements have been carried out, so that a high volume of waste has resulted. Also from the dismantling of irradiated facilities metallics waste has o be handed. Prior for equipment repair the hot cell involved has to be decontaminated and a large amount of lower active waste is produced. The waste is collected for conditioning and storing. There are different categories as: low active liquid waste, low active burnable waste, fuel waste, low and high active metallic waste. For each waste category special transport container are used. For the volume reduction our Waste Department is equipped with special facilities e.g.: furnace for burning, drying, liquids evaporators, hydraulic press for pelletizing, decontamination box for the dismantling ad cleaning of components. After conditioning the waste will be stored on site or transported to final storage in a salt mine (ERAM) . Special documentation has to be done for the acceptance of this waste

Legal Protection To The Infotainment Of Press Development In Indonesia

Directory of Open Access Journals (Sweden)

Anwar Fuadi

2015-08-01

Full Text Available Abstract In the socio-political life the press has become an integral part in democratic life. The press has become one of the means for citizens to bring their thoughts and opinions. Nowadays there is a tendency to increase the quantity of press publications sharp but not accompanied by a statement of the quality of journalism. The objective of this research is to understand the essence of the infotainment liability as a mass media in order to construct a freedom of the press principle which has legitimacy within the legal system of the press in Indonesia. The type of research used in this paper is normative research or also known as doctrinal research by reviewing the legal protection to the infotainment as a mass media in Indonesia. The outcomes of the research indicate that the role of infotainment in the legal system of the press in Indonesia refers to the legal construction of institutional and infotainment organizers itself. Legal liability of Infotainment essentially can be seen from the press obligations stipulated in the Law No. 40 of 1999 regarding the Press Law No. 32 of 2002 regarding Broadcasting as well as the Journalists Code of Ethics which support freedom of the press and expression.

Concept Design of Movable Beam of Hydraulic Press

Directory of Open Access Journals (Sweden)

Li Yancong

2017-01-01

Full Text Available The hydraulic press movable beam is one of the key components of the hydraulic press; its design quality impacts the accuracy of the workpiece that the press suppressed. In this paper, first, with maximum deflection and material strength as constraints, mechanical model of the movable beam is established; next, the concept design model of the moveable beam structure is established; the relationship among the force of the side cylinder, the thickness of the inclined plate, outer plate is established also. Taking movable beam of the 100MN type THP10-10000 isothermal forging hydraulic press as an example, the conceptual design result is given. This concept design method mentoned in the paper has general meaning and can apply to other similar product design.

Student Press in American Archives, Fall/Winter 1973-74.

Science.gov (United States)

National Council of Coll. Publications Advisers.

This issue of the "Student Press in America Archives List" contains 100 entries on current issues and information, as well as cases involving student press editors, advisers, student media, and the generic subject of the campus press, emphasizing censorship practices and principles. Information concerning how and where to obtain documents of…

Update on the KELT Transit Survey: Hot Planets around Hot Stars

Science.gov (United States)

Gaudi, B. Scott; Stassun, Keivan G.; Pepper, Joshua; KELT Collaboration

2018-01-01

The KELT Transit Survey consists of a pair of small-aperture, wide-angle automated telescopes located at Winer Observatory in Sonoita, Arizona and the South African Astronomical Observatory (SAAO) in Sutherland, South Africa. Together, they are surveying roughly 70% of the sky for transiting planets. By virtue of their small apertures (42 mm) and large fields-of-view (26 degrees x 26 degrees), KELT is most sensitive to hot Jupiters transiting relatively bright (V~8-11), and thus relatively hot stars. I will provide an update on the planets discovered by KELT, focusing in detail on our recent discoveries of very hot planets transiting several bright A and early F stars.

Engaging and Supporting a University Press Scholarly Community

Directory of Open Access Journals (Sweden)

Megan Taylor

2018-03-01

Full Text Available In this paper we explore how the development of The University of Huddersfield Press, a publisher of open access scholarly journals and monographs, has enabled the sharing of research with a wider online audience. We situate the development of the Press within a wider research environment and growing community of New University Presses (NUPs where there is an increasing demand for demonstrating research impact, which drives the need for improved analysis and reporting of impact data, a task that often falls within the remit of library and academic support services. We detail the benefits of the University Press Manager role in terms of ensuring professional service that delivers consistency and sustainability. We go on to outline the experiences of engaging with different online spaces and detail the extensive support for student authors. We argue that in order for the Press to support building a strong and engaged scholarly community and provide new spaces for emerging research, continued investment in both platform development and infrastructure is required.

Hot subluminous star: HDE 283048

International Nuclear Information System (INIS)

Laget, M.; Vuillemin, A.; Parsons, S.B.; Henize, K.G.; Wray, J.D.

1978-01-01

The star HDE 283048, located at α = 3/sup h/50/sup m/.3, delta = +25 0 36', shows a strong ultraviolet continuum. Ground-based observations indicate a hot-dominated composite spectrum. Several lines of evidence suggest that the hot component is a hot subdwarf. 2 figures

Effect of Equal Channel Angular Pressing on the Surface Roughness of Solid State Recycled Aluminum Alloy 6061 Chips

Directory of Open Access Journals (Sweden)

Adel Taha Abbas

2017-01-01

Full Text Available Solid state recycling through hot extrusion is a promising technique to recycle machining chips without remelting. Furthermore, equal channel angular pressing (ECAP technique coupled with the extruded recycled billet is introduced to enhance the mechanical properties of recycled samples. In this paper, the surface roughness of solid state recycled aluminum alloy 6061 turning chips was investigated. Aluminum chips were cold compacted and hot extruded under an extrusion ratio (ER of 5.2 at an extrusion temperature (ET of 425°C. In order to improve the properties of the extruded samples, they were subjected to ECAP up to three passes at room temperature using an ECAP die with a channel die angle (Φ of 90°. Surface roughness (Ra and Rz of the processed recycled billets machined by turning was investigated. Box-Behnken experimental design was used to investigate the effect of three machining parameters (cutting speed, feed rate, and depth of cut on the surface roughness of the machined specimens for four materials conditions, namely, extruded billet and postextrusion ECAP processed billets to one, two, and three passes. Quadratic models were developed to relate the machining parameters to surface roughness, and a multiobjective optimization scheme was conducted to maximize material removal rate while maintaining the roughness below a preset practical value.

WordPress 3 For Business Bloggers

CERN Document Server

Thewlis, Paul

2011-01-01

This is a practical, hands-on book based around a fictitious case study blog, which you will build on a development server using WordPress. The case study grows chapter by chapter, from installing your local development server, right up to the finished blog. This book is for anybody running or starting a business blog using WordPress, whether you plan to use your blog for PR and marketing, or want to profit directly from blogging.

FREEDOM OF PRESS AND JURY TRIAL IN ISTRIA 1848/1849

Directory of Open Access Journals (Sweden)

Dunja Pastović

2015-01-01

Full Text Available In Istria, as a part of the Austrian legal system, jury trial was initially introduced in the revolutionary year of 1848 only for press offenses, in the framework of aspirations for freedom of thought and expression through the press, which represented the most appropriate medium for the dissemination of new ideas and mobilization of the political masses. Trial by jury was supposed to secure impartial and objective trials, which could not be expected of professional judges due to insufficient guarantees of their impartiality. This paper examines the press-related orders and laws passed during 1848 and 1849 which regulated the freedom of press and jury jurisdiction. On the basis of an analysis of the legislative framework, jurisprudence, and the Istrian press during the examined time period, the author has decided that the introduction of the freedom of the press and jury trials for press offenses in 1848/1849 on the territory of Istria didn’t have a large practical significance.

Statistical hot spot analysis of reactor cores

International Nuclear Information System (INIS)

Schaefer, H.

1974-05-01

This report is an introduction into statistical hot spot analysis. After the definition of the term 'hot spot' a statistical analysis is outlined. The mathematical method is presented, especially the formula concerning the probability of no hot spots in a reactor core is evaluated. A discussion with the boundary conditions of a statistical hot spot analysis is given (technological limits, nominal situation, uncertainties). The application of the hot spot analysis to the linear power of pellets and the temperature rise in cooling channels is demonstrated with respect to the test zone of KNK II. Basic values, such as probability of no hot spots, hot spot potential, expected hot spot diagram and cumulative distribution function of hot spots, are discussed. It is shown, that the risk of hot channels can be dispersed equally over all subassemblies by an adequate choice of the nominal temperature distribution in the core

Comparison of Myoelectric Activity of a Selection of Upper Extremity Muscles while Doing Bench Press in Two Training Methods of TRX and Barbell Bench Press

Directory of Open Access Journals (Sweden)

Ahmad Reza Zibaei

2016-12-01

Conclusion: Considering these results it can be maintained that TRX bench press resistance training can be an alternative and effective practice for barbell bench press because, given the results, it can be appreciated that TRX bench press, dips low in the trunk, can lead to muscle activity close to the level of muscle activity during the barbell bench press drill.

Mannes of Forging and Perspectives of Knuckle Joint Presses Modernization

Directory of Open Access Journals (Sweden)

A. A. Antsifirov

2014-01-01

Full Text Available The article raises an issue to enhance technological forging capabilities on the known knuckle joint presses. It provides an illustrated overview of main design types of presses with crank-knuckle, toggle-knuckle, and knuckle joint mechanisms. The article also shows the advantages of the modernization way and improvement just of the active press equipment in terms of quality-to-price ratio, for example, as compared to the similar new foreign press equipment.It gives an overview of features, which provide forging processes owing to kinetic energy accumulated with the moving parts of the known designs of the knuckle joint presses depending on the drive actuating mechanism. Focused attention is drawn to forging on the knuckle joint presses for a time of contact with a work piece to be comparable with the duration of the work piece deformation process on hydraulic forging hammers. This allows us to forge thin-wall products with process automation compared to the forging hammers.Analysis of accumulating processes of kinetic energy by the moving parts of the knuckle joint presses has shown that presses driven by hydraulic cylinders or two screw hydraulic cylinder are the most optimal for technological operations as evidenced by references to domestic and foreign invention certificates and patents. The article presents disadvantages of forging on presses with hydraulic or pneumatic drive. It is a dependence of the deformation force, caused, mainly, by a force of the drive cylinder. The article gives linear movement rate quantities of press moving members depending on the drives of the actuating mechanism. Based on the above analysis of the features to manufacture work pieces on the knuckle joint presses, the article gives the rationale for the relevance of forging in a short period of time, provided that the moving parts of the press accumulate the required kinetic energy. This can be achieved only through modernization and improvement of forging

MIS hot electron devices for enhancement of surface reactivity by hot electrons

DEFF Research Database (Denmark)

Thomsen, Lasse Bjørchmar

A Metal-Insulator-Semiconductor (MIS) based device is developed for investigation of hot electron enhanced chemistry. A model of the device is presented explaining the key concepts of the functionality and the character- istics. The MIS hot electron emitter is fabricated using cleanroom technology...... and the process sequence is described. An Ultra High Vacuum (UHV) setup is modified to facilitate experiments with electron emission from the MIS hot electron emitters and hot electron chemistry. Simulations show the importance of keeping tunnel barrier roughness to an absolute minimum. The tunnel oxide...... to be an important energy loss center for the electrons tunneling through the oxide lowering the emission e±ciency of a factor of 10 for a 1 nm Ti layer thickness. Electron emission is observed under ambient pressure conditions and in up to 2 bars of Ar. 2 bar Ar decrease the emission current by an order...

Raman spectra of hot-pressed boron suboxide

CSIR Research Space (South Africa)

Machaka, R

2011-01-01

Full Text Available on in- situ/online measurements (such as GIXRD, Raman Spectroscopy, FIB- Electron Microscopy) during (i) ion implantation, (ii) PLD growth of nanoparticles SW/MW-CNTs, oxide semiconductor multi-layer, metal/Si and metal/metal systems. Moreover, He...], aluminium magnesium boride ? AlMgB14 [8], and the newly synthesized boron subnitride ? B13N2 [9, 10]. With hardness values reported between 24 GPa and 45 GPa [7, 11, 12], B6O is sometimes considered to be the third hardest material only after diamond...

Recent trend of administration on hot springs

Energy Technology Data Exchange (ETDEWEB)

Okubo, Shigeru [Environment Agency, Tokyo (Japan)

1989-01-01

The Environmental Agency exercises jurisdiction over Hot Spring Act, and plans to protect the source of the hot spring and to utilize it appropriately. From the aspect of utilization, hot springs are widely used as a means to remedy chronic diseases and tourist spots besides places for recuperation and repose. Statistics on Japanese hot springs showed that the number of hot spring spots and utilized-fountainhead increased in 1987, compared with the number in 1986. Considering the utilized-headspring, the number of naturally well-out springs has stabilized for 10 years while power-operated springs have increased. This is because the demand of hot springs has grown as the number of users has increased. Another reason is to keep the amount of hot water by setting up the power facility as the welled-out amount has decreased. Major point of recent administration on the hot spring is to permit excavation and utilization of hot springs. Designation of National hot spring health resorts started in 1954 in order to ensure the effective and original use of hot springs and to promote the public use of them, for the purpose of arranging the sound circumstances of hot springs. By 1988, 76 places were designated. 4 figs., 3 tabs.

Computational Prediction of Hot Spot Residues

Science.gov (United States)

Morrow, John Kenneth; Zhang, Shuxing

2013-01-01

Most biological processes involve multiple proteins interacting with each other. It has been recently discovered that certain residues in these protein-protein interactions, which are called hot spots, contribute more significantly to binding affinity than others. Hot spot residues have unique and diverse energetic properties that make them challenging yet important targets in the modulation of protein-protein complexes. Design of therapeutic agents that interact with hot spot residues has proven to be a valid methodology in disrupting unwanted protein-protein interactions. Using biological methods to determine which residues are hot spots can be costly and time consuming. Recent advances in computational approaches to predict hot spots have incorporated a myriad of features, and have shown increasing predictive successes. Here we review the state of knowledge around protein-protein interactions, hot spots, and give an overview of multiple in silico prediction techniques of hot spot residues. PMID:22316154

Movement Features Which Describe the Flat Bench Press

Directory of Open Access Journals (Sweden)

Król Henryk

2017-06-01

Full Text Available Introduction. In sport technique studies, motion features can be useful as they have a certain defined measure [1]. In this work, we examined the following three features: the structure of the movement (all the characteristics of the movement, the fluency of the movement, and the rhythm of the movement. The aim of the study was to determine the usefulness of the selected movement features in the evaluation of the flat bench press. The protocol of the study included a flat bench press with free weights and a “touch-and-go” technique. Material and methods. The study involved twenty healthy men; however, only two were selected for analysis. The first subject was a 25-year-old powerlifter (body mass = 95 kg; body height = 182 cm; 1-RM in flat bench press = 145 kg. The second one was a 25-year-old bodybuilder (body mass = 77 kg; body height = 175 cm; 1-RM in flat bench press = 100 kg. The subjects performed consecutive sets of a single repetition of flat bench pressing with an increasing load (70, 80, 90, and 100% 1-RM, with the anticipated maximum weight, until the completion of one repetition maximum. Multidimensional movement analysis was made with the measuring system Smart-E (BTS, Italy, which consisted of six infrared cameras (120 Hz and a wireless module to measure muscle bioelectric activity (Pocket EMG. Results. It was demonstrated that the internal structure of the bench press performed by the bodybuilder and the powerlifter was different. As the time-history of barbell kinematics (the acceleration-time curve showed, with increased loading of the barbell, the rhythm of the flat bench press changed, and the fluidity of the movement worsened.

Myths About Press Freedom

Directory of Open Access Journals (Sweden)

Kaarle Nordenstreng

2007-06-01

Full Text Available This article intends to rectify three popular beliefs related to press freedom: (1 that the idea of a free marketplace of ideas with a self-righting truth belongs to original liberalism, (2 that UNESCO’s primary mission is to promote freedom of information, and (3 that the Universal Declaration of Human Rights provides legal safeguards for the media. These beliefs are shown, on the basis of the legacy of liberalism and documents of the international community, to be misleading myths. Instead of accurate readings of the idea of freedom, they serve as ideological positions which are harmful to democracy. The Millennium Declaration provides further proof that the international community has a much more balanced view of freedom of information than that typically held by media professionals. Therefore it is important to liberate the concept of press freedom from its ideological baggage.

Hot Spots and Hot Moments of Nitrogen in a Riparian Corridor

Science.gov (United States)

Dwivedi, Dipankar; Arora, Bhavna; Steefel, Carl I.; Dafflon, Baptiste; Versteeg, Roelof

2018-01-01

We use 3-D high-resolution reactive transport modeling to investigate whether the spatial distribution of organic-carbon-rich and chemically reduced sediments located in the riparian zone and temporal variability in groundwater flow direction impact the formation and distribution of nitrogen hot spots (regions that exhibit higher reaction rates when compared to other locations nearby) and hot moments (times that exhibit high reaction rates as compared to longer intervening time periods) within the Rifle floodplain in Colorado. Groundwater flows primarily toward the Colorado River from the floodplain but changes direction at times of high river stage. The result is that oxic river water infiltrates the Rifle floodplain during these relatively short-term events. Simulation results indicate that episodic rainfall in the summer season leads to the formation of nitrogen hot moments associated with Colorado River rise and resulting river infiltration into the floodplain. The results further demonstrate that the naturally reduced zones (NRZs) present in sediments of the Rifle floodplain have a higher potential for nitrate removal, approximately 70% greater than non-NRZs for typical hydrological conditions. During river water infiltration, nitrate reduction capacity remains the same within the NRZs, however, these conditions impact non-NRZs to a greater extent (approximately 95% less nitrate removal). Model simulations indicate chemolithoautotrophs are primarily responsible for the removal of nitrate in the Rifle floodplain. These nitrogen hot spots and hot moments are sustained by microbial respiration and the chemolithoautotrophic oxidation of reduced minerals in the riparian zone.

High Thermal Conductivity and High Wear Resistance Tool Steels for cost-effective Hot Stamping Tools

Science.gov (United States)

Valls, I.; Hamasaiid, A.; Padré, A.

2017-09-01

In hot stamping/press hardening, in addition to its shaping function, the tool controls the cycle time, the quality of the stamped components through determining the cooling rate of the stamped blank, the production costs and the feasibility frontier for stamping a given component. During the stamping, heat is extracted from the stamped blank and transported through the tool to the cooling medium in the cooling lines. Hence, the tools’ thermal properties determine the cooling rate of the blank, the heat transport mechanism, stamping times and temperature distribution. The tool’s surface resistance to adhesive and abrasive wear is also an important cost factor, as it determines the tool durability and maintenance costs. Wear is influenced by many tool material parameters, such as the microstructure, composition, hardness level and distribution of strengthening phases, as well as the tool’s working temperature. A decade ago, Rovalma developed a hot work tool steel for hot stamping that features a thermal conductivity of more than double that of any conventional hot work tool steel. Since that time, many complimentary grades have been developed in order to provide tailored material solutions as a function of the production volume, degree of blank cooling and wear resistance requirements, tool geometries, tool manufacturing method, type and thickness of the blank material, etc. Recently, Rovalma has developed a new generation of high thermal conductivity, high wear resistance tool steel grades that enable the manufacture of cost effective tools for hot stamping to increase process productivity and reduce tool manufacturing costs and lead times. Both of these novel grades feature high wear resistance and high thermal conductivity to enhance tool durability and cut cycle times in the production process of hot stamped components. Furthermore, one of these new grades reduces tool manufacturing costs through low tool material cost and hardening through readily

News from the Library: PressDisplay on mobile devices!

CERN Multimedia

CERN Library

2013-01-01

You are probably already using PressDisplay to read newspapers online, but for those of you who are not yet aware of this service, PressDisplay is an online portal where you can browse and read online articles from more than 1,900 newspapers from 95 countries, as soon as they are published.   Whether you are an experienced user or a beginner, we have good news concerning PressDisplay: our license now permits you to download complete newspaper issues to your mobile devices and read them offline wherever you like. To do that, you have to use the mobile app PressReader. Instructions on how to install the PressReader app are available here: For Ipad For Android smartphone For Android tablet For Windows 8 devices For BlackBerry Playbook For Android eReader Your feedback is welcome! Please contact us by e-mail.

Hot Spot Removal System: System description

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-09-01

Hazardous wastes contaminated with radionuclides, chemicals, and explosives exist across the Department of Energy complex and need to be remediated due to environmental concerns. Currently, an opportunity is being developed to dramatically reduce remediation costs and to assist in the acceleration of schedules associated with these wastes by deploying a Hot Spot Removal System. Removing the hot spot from the waste site will remove risk driver(s) and enable another, more cost effective process/option/remedial alternative (i.e., capping) to be applied to the remainder of the site. The Hot Spot Removal System consists of a suite of technologies that will be utilized to locate and remove source terms. Components of the system can also be used in a variety of other cleanup activities. This Hot Spot Removal System Description document presents technologies that were considered for possible inclusion in the Hot Spot Removal System, technologies made available to the Hot Spot Removal System, industrial interest in the Hot Spot Removal System`s subsystems, the schedule required for the Hot Spot Removal System, the evaluation of the relevant technologies, and the recommendations for equipment and technologies as stated in the Plan section.

Hot Spot Removal System: System description

International Nuclear Information System (INIS)

1997-09-01

Hazardous wastes contaminated with radionuclides, chemicals, and explosives exist across the Department of Energy complex and need to be remediated due to environmental concerns. Currently, an opportunity is being developed to dramatically reduce remediation costs and to assist in the acceleration of schedules associated with these wastes by deploying a Hot Spot Removal System. Removing the hot spot from the waste site will remove risk driver(s) and enable another, more cost effective process/option/remedial alternative (i.e., capping) to be applied to the remainder of the site. The Hot Spot Removal System consists of a suite of technologies that will be utilized to locate and remove source terms. Components of the system can also be used in a variety of other cleanup activities. This Hot Spot Removal System Description document presents technologies that were considered for possible inclusion in the Hot Spot Removal System, technologies made available to the Hot Spot Removal System, industrial interest in the Hot Spot Removal System''s subsystems, the schedule required for the Hot Spot Removal System, the evaluation of the relevant technologies, and the recommendations for equipment and technologies as stated in the Plan section

Pressing technology for large bottoms

International Nuclear Information System (INIS)

Jilek, L.

1986-01-01

The technology has been selected of a circular plate bent into the shape of a trough, for pressing bottoms of pressure vessels from a circular plate of large diameter. The initial sheet is first bent in the middle by heating with the edges remaining straight. These are then welded longitudinally by electroslag welding and the circular shape is flame cut. The result will be a plate with a straight surface in the middle with raised edges which may be pressed into the desired shape. In this manner it is also possible to press pressure vessel bottoms with tube couplings from plates which are thickened in the middle and drilled; additional welding is then eliminated. Deformation from heat treatment may be avoided by the use of a fixture in the shape of a ring with a groove into which is fixed the edge of the bottom. During hardening of the bottom it will be necessary to care for the withdrawal of vapours and gases which would hamper uniform cooling. Bottom hardening with the grill and the cupola downwards has been proven. Deformation which occurs during treatment may to a certain extent be removed by calibration which cannot, however, be made without special fixtures and instruments. (J.B.)

Nitrogen cycling in Hot Spring Sediments and Biofilms (Invited)

Science.gov (United States)

Meyer-Dombard, D. R.; Burton, M. S.; Havig, J. R.; Shock, E.

2010-12-01

capacity for nitrogen fixation as a function of changing community structure become apparent. Our results provide insight into shifts in genomic and transcriptomic function in the context of niches within hot spring environments, and the effect of availability of fixed nitrogen on the growth habit of microbial communities in situ in these ecosystems. [1] Havig et al., 2010. Merging isotopes and community genomics in a siliceous sinter-depositing hot spring. Journal of Geophysical Research-Biogeosciences (in press). [2] Raymond et al., 2008. EOS Trans AGU. Abstract B14A-03. [3] Hall et al., 2008. Molecular characterization of the diversity and distribution of a thermal spring microbial community using rRNA and metabolic genes. AEM 74:4910-4922. [4] Steunou et al., 2006. In situ analysis of nitrogen fixation and metabolic switching in unicellular thermophilic Cyanobacteria inhabiting hot spring microbial mats. PNAS 103:2398-2403. [5] Boyd et al., 2009. CO2 uptake and fixation by a thermoacidophilic microbial community attached to precipitated sulfur in a geothermal spring. AEM 75:4289-4296.

The Distinction of Hot Herbal Compress, Hot Compress, and Topical Diclofenac as Myofascial Pain Syndrome Treatment.

Science.gov (United States)

Boonruab, Jurairat; Nimpitakpong, Netraya; Damjuti, Watchara

2018-01-01

This randomized controlled trial aimed to investigate the distinctness after treatment among hot herbal compress, hot compress, and topical diclofenac. The registrants were equally divided into groups and received the different treatments including hot herbal compress, hot compress, and topical diclofenac group, which served as the control group. After treatment courses, Visual Analog Scale and 36-Item Short Form Health survey were, respectively, used to establish the level of pain intensity and quality of life. In addition, cervical range of motion and pressure pain threshold were also examined to identify the motional effects. All treatments showed significantly decreased level of pain intensity and increased cervical range of motion, while the intervention groups exhibited extraordinary capability compared with the topical diclofenac group in pressure pain threshold and quality of life. In summary, hot herbal compress holds promise to be an efficacious treatment parallel to hot compress and topical diclofenac.

Hot particles

International Nuclear Information System (INIS)

Merwin, S.E.; Moeller, M.P.

1989-01-01

Nuclear Regulatory Commission (NRC) licensees are required to assess the dose to skin from a hot particle contamination event at a depth of skin of7mg/cm 2 over an area of 1 cm 2 and compare the value to the current dose limit for the skin. Although the resulting number is interesting from a comparative standpoint and can be used to predict local skin reactions, comparison of the number to existing limits based on uniform exposures is inappropriate. Most incidents that can be classified as overexposures based on this interpretation of dose actually have no effect on the health of the worker. As a result, resources are expended to reduce the likelihood that an overexposure event will occur when they could be directed toward eliminating the cause of the problem or enhancing existing programs such as contamination control. Furthermore, from a risk standpoint, this practice is not ALARA because some workers receive whole body doses in order to minimize the occurrence of hot particle skin contaminations. In this paper the authors suggest an alternative approach to controlling hot particle exposures

Simulation Model of Automated Peat Briquetting Press Drive

Directory of Open Access Journals (Sweden)

A. A. Marozka

2012-01-01

Full Text Available The paper presents the developed fully functional simulation model of an automated peat briquetting press drive. The given model makes it possible to reduce financial and time costs while developing, designing and operating a double-stamp peat briquetting press drive.

Hot-Film and Hot-Wire Anemometry for a Boundary Layer Active Flow Control Test

Science.gov (United States)

Lenahan, Keven C.; Schatzman, David M.; Wilson, Jacob Samuel

2013-01-01

Unsteady active flow control (AFC) has been used experimentally for many years to minimize bluff-body drag. This technology could significantly improve performance of rotorcraft by cleaning up flow separation. It is important, then, that new actuator technologies be studied for application to future vehicles. A boundary layer wind tunnel was constructed with a 1ft-x-3ft test section and unsteady measurement instrumentation to study how AFC manipulates the boundary layer to overcome adverse pressure gradients and flow separation. This unsteady flow control research requires unsteady measurement methods. In order to measure the boundary layer characteristics, both hot-wire and hot-film Constant Temperature Anemometry is used. A hot-wire probe is mounted in the flow to measure velocity while a hot-film array lays on the test surface to measure skin friction. Hot-film sensors are connected to an anemometer, a Wheatstone bridge circuit with an output that corresponds to the dynamic flow response. From this output, the time varying flow field, turbulence, and flow reversal can be characterized. Tuning the anemometers requires a fan test on the hot-film sensors to adjust each output. This is a delicate process as several variables drastically affect the data, including control resistance, signal input, trim, and gain settings.

SHOSPA-MOD, Hot Spot Factors for Fuel and Clad, Hot Channel Factors

International Nuclear Information System (INIS)

Amendola, A.

1982-01-01

1 - Nature of the physical problem solved: SHOSPA evaluates the hot spot factors for fuel and cladding as well as the hot channel factor as a function of the confidence level. Moreover, it evaluates the probability on n hot subassemblies. The code has been developed with emphasis on sodium cooled fast reactors, but it is applicable to any type of reactors constituted of bundled fuel rods with single phase coolant. An option for plotting is available in this version. 2 - Restrictions on the complexity of the problem: This code is applicable to any type of reactors constituted of fuel rods with single phase coolant

Predictor of regulation of uranium dioxide powder pressing process

International Nuclear Information System (INIS)

Motta, Eduardo Souza; Araujo, Victor Hugo Leal de; Bernardelli, Sergio Henrique

2007-01-01

One of the most important steps of the uranium dioxide pellets fabrication used in the nuclear fuel elements is the green pellets pressing. The target density of the pellets after the sintering process determines the density of the green pellet. To meet the same sintered target density the green density may vary according to the powder characteristics. These variations implies in changing the regulation of the press for different powder's patches. The regulation done empirically imply in productivity loss and necessity of reprocessing the pellets pressed during the press regulation and also depends on the operator experience. At this work, was developed an artificial neural network feed forward back propagation to predict the press regulation, depending on the powder characteristics and the green pellet's target density. The results obtained at INB - Industrias Nucleares do Brasil S. A. during the fabrication of the fifth recharge of Angra II nuclear power plant are presented. (author)

Type synthesis for 4-DOF parallel press mechanism using GF set theory

Science.gov (United States)

He, Jun; Gao, Feng; Meng, Xiangdun; Guo, Weizhong

2015-07-01

Parallel mechanisms is used in the large capacity servo press to avoid the over-constraint of the traditional redundant actuation. Currently, the researches mainly focus on the performance analysis for some specific parallel press mechanisms. However, the type synthesis and evaluation of parallel press mechanisms is seldom studied, especially for the four degrees of freedom(DOF) press mechanisms. The type synthesis of 4-DOF parallel press mechanisms is carried out based on the generalized function(GF) set theory. Five design criteria of 4-DOF parallel press mechanisms are firstly proposed. The general procedure of type synthesis of parallel press mechanisms is obtained, which includes number synthesis, symmetrical synthesis of constraint GF sets, decomposition of motion GF sets and design of limbs. Nine combinations of constraint GF sets of 4-DOF parallel press mechanisms, ten combinations of GF sets of active limbs, and eleven combinations of GF sets of passive limbs are synthesized. Thirty-eight kinds of press mechanisms are presented and then different structures of kinematic limbs are designed. Finally, the geometrical constraint complexity( GCC), kinematic pair complexity( KPC), and type complexity( TC) are proposed to evaluate the press types and the optimal press type is achieved. The general methodologies of type synthesis and evaluation for parallel press mechanism are suggested.

Application of Cyclone to Removal of Hot Particulate in Hot Cell

International Nuclear Information System (INIS)

Kim, Gye Nam; Lee, Sung Yeol; Won, Hui Jun; Jung, Chong Hun; Oh, Won Zin

2005-01-01

The size and main ingredient of hot particulate generated during the nuclide experiment in hot cells of nuclear facilities were 0.5300 μm and UO 2 . A cyclone filter equipment which consists of a cyclone and Bag/HEPA filter was devised to remove hot particulate generated during the nuclide experiment in hot cells of nuclear facilities. The experimental conditions to maximize the collection efficiency of hot particulate were suggested through experiments done with the cyclone filter equipment. With the large size of simulated particulate, the collection efficiency of the particulate was high. When the size of simulated particulate was more than 5 μm, the collection efficiency of the particulate was more than 80% and when the size of simulated particulate was less than 1.0 μm, the collection efficiency decreased by less than. If the inflow velocity of simulated particulate was increased, the collection efficiency of the particulate was also increased. When the inflow velocity of simulated particulate was more than 12 m/sec, the collection efficiency was higher than , but after 17 m/sec inflow velocity, no change observed. The collection efficiency of the simulated particulate can be enhanced with the length of vortex finder inside the chamber. With the length of vortex finder, 7.2 cm, the observed collection efficiency of the particulate was the maximum. Moreover, when the sub-cone was attached under the cyclone, the collection efficiency of cyclone increased 2%. It was found that effect by attachment of sub-cone was not serious.

The regulation of press freedoms (1863-1867

Directory of Open Access Journals (Sweden)

Laurence Coudart

2015-10-01

Full Text Available The main objective of this essay is to analyze the legislation affecting the press during the French Intervention and the Second Mexican Empire and establish their regulatory effects. These regulations are frequently ignored by the historiography. The article is limited to the origins, innovations, mechanisms and evolution of printing regulations during this period. As a whole, this allows the reader to observe the restrictive conception of press freedom held by the Mexican political class and their willingness, during the second half of the 19th Century, to turn to prohibitive, repressive, authoritarian and centralist legislation. The article also reveals the extent to which Imperial legislation and its logic of censorship were neither unprecedented nor sudden foreign impositions but instead the expressions of a long-lasting desire for government control over the press.