In this work, wet ballmilling method is used in order to improve hydrogen sorption behaviour due to its improved microstructure of solid hydrogen materials. Compared to traditional ballmilling method, wet ballmilling has benefits on improvement of MgH{sub 2} microstructure and further influences on its hydrogen sorption behavior. With the help of solvent tetrahydrofuran (THF), wet ballmilled MgH{sub 2} powder has much smaller particle size and its specific surface area is 7 times as large as that of dry ballmilled MgH{sub 2} powder. Although after ballmilling the grain size is decreased a lot compared to as-received MgH{sub 2} powder, the grain size of wet ballmilled ...
A mixture of powders of silica and aluminum nitride is subjected to high-energy ballmilling for different milling times. This material is subsequently compacted by uniaxial pressing and sintered at 1450 deg. C. The resulting pellets are crushed and analysed by X-ray diffraction. For short milling times, the amount of phase transformation is minimal and the resulting material mostly consists of cristobalite and aluminum nitride. For long milling times, nanocrystalline #beta#-SiAl_2O_2N_2 is mainly produced.
The Co-Si composites with a molar ratio of 2:1 are synthesized by ball-milling method and their potential as negative electrode materials of Ni-MH batteries is investigated. The microstructure, morphology and chemical state of the ball-milled Co-Si composites are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). XRD patterns show that the ball-milled samples for 10 and 20 h contain Co, Si and Co{sub 2}Si phases, and the ball-milled samples for 40 and 60 h are mainly amorphous Co{sub 2}Si alloys. In contrast to the high initial discharge capacity (1012 mAh/g) obtained for the sample ball-milled for 10 h, the discharge capacities of the samples ball-milled for 40 and 60 h are very low. It indicates that the hydrogen storage capacity of pure Co{sub 2}Si alloy is very ...
BackgroundLignocellulosic biomass such as wood is an attractive material for fuel ethanol production. Pretreatment technologies that increase the digestibility of cellulose and hemicellulose...Full Text Available
A steadily increasing part of comminution is nowadays carried out by tube ballmills. Our investigations are a first step to a possible tuning of material distribution with mechanical stress characteristic of the grinding media charge, that is essential for a high efficiency of grinding. A BOND mill filled with porcelain balls as grinding media and labelled corundum (Au-198) as grinding material was used to measure the distribution of material over the cross-section. The evaluation was made by linear interpolation between all combinations of adjacent measuring points to calculate all coordinates with equal intensity for each selected level of activity. Two plottings showing the dependence of material distribution on the rotating speed are presented. (author).
Spherical {beta}-Ni(OH){sub 2} was modified by a low-cost method of normal ballmilling (NBM), and the physical properties of both ball-milled and un-milled Ni(OH){sub 2} were characterized by transmission electron microscopy, specific surface area, particle size distribution and X-ray diffraction. It was found that NBM could obviously increase the surface area, decrease the particle and crystallite size, and reduce the crystallinity of {beta}-Ni(OH){sub 2}, which were advantageous to the improvement of the electrochemical activity of Ni(OH){sub 2}. NBM also lowered the packing density and flowability of Ni(OH){sub 2}, as revealed by the measurements of tapping density and angle of repose. Electrochemical performances of pasted nickel electrodes with an addition of ball-milled Ni(OH){sub 2} to spherical Ni(OH){sub 2} as the active material were investigated, and ...
An investigation on the hydrogen generation by reacting ball-milled Mg-based materials in different alcoholic solutions (methanol, ethanol, 2-propanol) was performed. The MgH{sub 2} reactivity in methanol is very low (maximum conversion yield <10%) and no improvement is induced by the ballmilling treatment. In contrast, the ballmilling affects greatly the Mg reactivity in methanol. The Mg powder milled for 30min displays a maximum conversion yield of 47% compared to 3% for unmilled Mg powder. Its high reactivity is ascribed to the creation of numerous defects and fresh surfaces during the initial stage of the milling process, favoring the corrosion of Mg in methanol. In addition, the presence of water in the methanol solution inhibits drastically the alcoholysis reaction despite its low amount (0.3vol%). The ...
Cu/YSZ cermet (40 and 60 vol.% Cu powder with balance YSZ) is a more economical cathode material than the conventional Ni/YSZ cermet for high temperature electrolysis (HTE) of water vapor and it was successfully fabricated by high-energy ball-milling of Cu and YSZ powders, pressing into pellets (o 13 mm x 2 mm) and subsequent sintering process at 700 deg. C under flowing 5%-H{sub 2}/Ar gas. The Cu/YSZ composite material thus fabricated was characterized using various analytical tools such as XRD, SEM, and laser diffraction and scattering method. Electrical conductivity of sintered Cu/YSZ cermet pellets thus fabricated was measured by using 4-probe technique for comparison with that of conventional Ni/YSZ cermets. The effect of composite composition on the electrical conductivity was investigated and a marked increase in electrical conductivity for copper contents greater than 40 vol.% in the composite was explained by ...
LiFePO{sub 4} cathode materials with distinct particle sizes were prepared by a planetary ball-milling method. The effects of particle size on the morphology, thermal stability and electrochemical performance of LiFePO{sub 4} cathode materials were investigated. The ball-milling method decreased particle size, thereby reducing the length of diffusion and improving the reversibility of the lithium ion intercalation/deintercalation. It is worth noting that the small particle sample prepared using malonic acid as a carbon source achieved a high capacity of 161 mAh g{sup -1} at a 0.1 C rate and had a very flat capacity curve during the early 50 cycles. However, the big particle samples ({proportional_to}400 nm) decayed more dramatically in capacity than the small particle size samples ({proportional_to}200 nm) at high current densities. The improvement in electrode performance was mainly due to the fine ...
To study the effect of CuO on the electrochemical properties of MgNi alloy, the MgNi-xCuO (x = 3, 5 and 10 wt%) composites were prepared by ball-milling method. The X-ray diffraction (XRD) analysis showed that the structures of the composites were amorphous. The cycle stability of the composites was improved compared to pure MgNi alloy due to the enhancement of the anti-corrosion property in the alkaline electrolyte, and the composite with 5 wt% CuO ball-milled for 15 h exhibited the best performance. Electrochemical impedance spectroscopy (EIS) and potential-step measurements indicated that the electrochemical kinetics of the composites was improved.
Mechanical alloying is an important pre-requisite for the manufacturing of heat resistant oxide-dispersion-strengthened superalloys. Though the microstructure of these materials after hot extrusion and recrystallization treatment is well documented, little is known about the microstructural evolution during ball-milling. A method was tested to prepare electron transparent foils and extraction replica from powder particles for TEM investigations. The microstructure was found to consist of a Ni-Cr-Al solid solution in which submicron particles of refractory metals were embedded. The extremely fine grainize of about 50 nm is the consequence of severe plastic deformation. Yttria particles could not be detected in the powder after ballmilling, but after a heat treatment at 1000 C the well-known fine dispersion of oxide particles was evident. (orig.)
Ultrafine particles of Co-P were synthesized by direct ballmilling of Co and P powders and also investigated as a reversible hydrogen storage electrode material. The electrochemical results demonstrated that the reversible charge-discharge capacity of the Co-P electrode can reach more than 300mAh/g. In addition, the cycling ability and high rate capability of the Co-P electrode are excellent with only 5% capacity decay after 100 cycles at a high rate of 300mA/g. The temperature-programmed desorption measurements (TPD) of the Co-P electrode revealed that the charge and discharge reactions of the Co-P electrode proceeds predominantly through electrochemical hydrogen storage mechanism and the electrooxidation of cobalt contributes only a negligible part to the reversible electrochemical capacity. (author)
NaCl doped MgCl_2.nEtOH adducts were prepared by ball-milling MgCl_2.2.5EtOH with NaCl. Both the ball-milled MgCl_2.nEtOH/NaCl mixture and pure MgCl_2.2.5EtOH adducts were analyzed by X-ray diffraction (XRD), transmission electron microscope (TEM), thermogravimetry (TG) and differencial scanning calorimetry (DSC). A simple MgCl_2.nEtOH/NaCl mixture without ball-milling treatment was also studied for comparison. Two kinds of mixed crystals, Na_2MgCl_4 and NaMgCl_3, were found to be formed in a ball-milled mixture that contained 16 mol.% NaCl. TG and DSC analysis of the samples also provided indirect evidences supporting the presence of the mixed crystals in the ball-milled mixture. Adding certain amounts of NaCl in MgCl_2.2.5EtOH adduct, either by co-milling or by simple mixing, greatly increased the thermal stability of the adduct, but thermal decomposition ...
MmMg{sub 12}-Ni amorphous or nanocrystalline composites (Mm: Ce-rich mischmetal) were prepared through the ball-milling method, and their electrochemical hydrogen storage performance was investigated and compared with that of ball-milled CeMg{sub 12}-Ni composites. It was found that the ball-milled MmMg{sub 12}-Ni composites had larger initial discharge capacities and better high rate dischargeability. Analysis of electrochemical impedance spectra (EIS) shows that the reaction resistance and hydrogen diffusion resistance of the ball-milled MmMg{sub 12}-Ni composites are lower as a result of the decrease in Ce content, and thus can contribute to the larger discharge capacity and better high rate dischargeability. Additionally, the cycle performance of the ball-milled MmMg{sub 12}-Ni composites is better than those of the ball-milled CeMg{sub 12}-Ni composites. ...
Medium-density polyethylene/multiwall carbon nanotube (MDPE/MWCNT) nanocomposites were produced by a mechanical milling method using a high-energy ballmill. The MDPE and MWCNTs were added to the ballmill at a constant 20:1 weight ratio of ball/powders and milled for 10 h to obtain polyethylene matrix nanocomposites reinforced with 0.5, 1, 2.5, and 5 weight percent of MWCNTs. To clarify the role of both MWCNT content and milling time on the morphology of MDPE, some nanocomposite samples were investigated by using a scanning electron microscope. To evaluate the role of milling on the microstructure of the nanocomposites, very thin films of MDPE/MWCNTs were prepared and studied by transmission electron microscopy. Thermal behavior of these nanocomposites was investigated by using differenti...
A study was made of the variation in strength characteristics of group IV transition metal carbon nitrides alloyed with carbides or group V metal nitrides. A complex solid solution of titanium-niobium carbonitride was preliminarily synthesized to a homogeneous equilibrium state and then crushed. The calculated quantity of binder metal was added as elemental powders, the mixture was vibration ballmilled in ethanol and the plasticized charge was used to press experimental specimens for mechanical testing. The studies showed that the high-temperature strength properties of the new cermet are superior to standard type KNT. The material is thus promising for use in the manufacture of tools. 8 references, 3 figures.
Nanodimensional powders of cubic copper ferrite are synthesized by two-steps procedure of co-precipitation of copper and iron hydroxide carbonates, followed by mechanochemical treatment. X-ray powder diffraction, Moessbauer spectroscopy and temperature-programmed reduction are used for the characterization of the obtained materials. Their catalytic behavior is tested in methanol decomposition to hydrogen and CO and total oxidation of toluene. Formation of nanosized ferrite material is registered even after one hour of milling time. It is established that the prolonging of treatment procedure decreases the dispersion of the obtained product with the appearance of Fe2O3. It is demonstrated that the catalytic behavior of the samples depends not only on their initial phase composition, but on the concomitant ferrite phase transformations by the influence of the reaction medium. -- Graphical abstract: It is demonstrated that the ...
FeSi{sub 6}/graphite composite was prepared by mechanical ballmilling. The FeSi{sub 6} alloy particles consist of an electrochemically active silicon phase and inactive phases FeSi{sub 2}, distributed uniformly in the graphite matrix. The composite anode offers a large reversible capacity (about 800 mAh g{sup -1}) and good cycleability, due to the buffering effect of the inactive FeSi{sub 2} phase and graphite layers on the volumetric changes of Si phase during lithium-Si alloying reaction. Since FeSi{sub 6} alloy is a low-cost industrial material, this alloy compound provides a possible alternative for development of high capacity lithium-ion batteries. (author)
An enzyme active against carboxymethyl cellulose (CMC) was purified from the stationary-phase-culture supernatant of Clostridium josui grown in a medium containing ball-milled cellulose. The purification...Full Text Available
Full text: It was recently-established for hexagonal barium ferrite-industrially important magnetically hard material that refinement of the crystallite dimensions into the nanoscale regime, typically #<=# 10 nm, leads after heat treatment at temperatures 800-1000 deg C to significant coercivity increase of up to 6.5 kOe (#approx#3-4 times) with saturation magnetisation values of 50-55 emu/g (#approx#95% of bulk at room temperature). High-energy mechanochemical processing has been applied to prepare nanostructural (nanocrystalline-amorphous) composites. High resolution electron microscopy studies reveal that the enhancement of the final magnetic properties was due to formation of magnetically noninteracting #approx#l,#mu#m Ba-ferrite particles with 5-10 nm amorphous surface layer - depending on annealing parameters. Similar situation was established also for ballmilled strontium ferrite (SrFe_1_2O_1_9) powders where ...
The ball-milling method was used to produce Mg-50 wt.% ZrFe{sub 1.4}Cr{sub 0.6} composite. The thermodynamic, kinetic, and cycling properties, as well as the resistance to oxidation were examined. This composite possesses excellent kinetic properties, even at moderate temperature. Scanning electron microscopy, energy-dispersive spectrum, transmission electron microscopy and X-ray diffraction were used to characterize the composite before and after hydriding. The fine ZrFe{sub 1.4}Cr{sub 0.6} particles covering Mg particles acting as a ''catalytic film'', a significant amount of imperfections and some alloy powder in the Mg matrix introduced by ballmilling all contributed to the enhanced absorption/desorption rate. (orig.)
Nano materials are usually difficult to prepare. This work presents a simple way of preparing LiMn{sub 2}O{sub 4} nano powders using the high-energy ballmilling method. This method has the advantage of producing pure, single-phase and crystalline nano powders. The milling method is carefully controlled to avoid unwanted chemical reactions that may change the stoichiometry of the material. Nano powders of between 30 and 50 nm are obtained. Structural studies of the nano powders, as well as the more conventional micron-sized LiMn{sub 2}O{sub 4}, are made using X-ray diffraction and neutron diffraction methods. Electrochemical evaluation of the materials is undertaken with a three-probe cyclic voltammetry technique and galvanostatic charge-discharge measurements. Structural studies reveal that not only are the crystallites of the nano powders much reduced in size ...
Ultra fine tungsten carbide and cobalt powders were milled by high energy planetary ballmill at different ball to powder weight ratios (BPR) to produce particles of WC-10wt%Co hard metal in nanometer scale size. Microstructural characterizations by TEM show that the particle size of tungsten carbide was achieved to 32nm after milling at 15 BPR during 10h. In order to reduce the WC grain growth during the sintering process, tantalum carbide was added to the hard metal as a WC grain growth inhibitor. The nano hard metal powders were compacted at 200MPa pressure and sintered at 1370-1450degreeC temperatures in a high purity hydrogen atmosphere. The results show that the addition of 0.6wt% of TaC improves the hardness and fracture toughness from 1493 HV30 and 11.8MPam (for TaC free sample) to...
Aiming to realize ball bearings operable in a vacuum and under high temperature, silicon nitride (Si3N4) ceramic ball bearings were tested. The tested ball bearings were angular contact ball bearings composed of silicon nitride with sputtered molybdenum disulfide coating using a retainer of hot-pressed self-lubricating composite material. The time variation of the frictional torque was examined for the operations under the conditions at 500{degree}C in a vacuum at a rotational speed of 600 rpm and 50N thrust load for 5{times}10{sup 7}revolutions (1400 hours) and for 1.5{times}10{sup 8}revolutions (4200 hours). Excellent tribological performance was obtained. The ball bearings are lubricated with the molybdenum disulfide film at the initial stage of the operation and with a transfer film formed from the retainer material to the ...
Magnesium-based alloys are among the promising materials for hydrogen storage and fuel cell applications due to their high hydrogen content. In the present work, we investigated the hydrogen release/uptake properties of the Mg-Ti-H system. Samples were prepared from the mixtures of MgH{sub 2} and TiH{sub 2} in molar ratios of 7:1 and 4:1 using a high-energy-high-pressure (HEHP) mechanical ball-milling method under 13.8 MPa hydrogen pressure. Thermogravimetric analysis (TGA) showed that a relatively large amount of hydrogen (5.91 and 4.82 wt.%, respectively, for the above two samples) was released between 126 and 313 C while temperature was increased at a heating rate of 5 C min{sup -1} under an argon flow. The onset dehydrogenation temperature of these mixtures, which is 126 C, is much lower than that of MgH{sub 2} alone, which is 381 C. The activation energy of dehydrogenation was 71 kJ mol{sup -1}, which is much smaller than that of ...
This work is focused on effect of various cooling strategies on surface roughness and tool wear during computer aided milling of soft workpiece materials. These milling operations were selected as dry milling, cool air cooling milling and fluid cooling milling. A cool air cooling system was designed and produced to cool end milling tools. Cool air was produced by a vortex tube. Annealed AISI 1050 was used as the workpiece material and cutting tool material was selected as HSS-Co8 DIN 844/BN. Optimal cutting parameters were selected according to workpiece hardness from reference catalog and kept for all tests. Tool wear and surface quality were measured for three different cooling types changing from ten minute machining time to thirty minute machining time. As a result, the surface roughne...
Nanocrystalline Fe75Si20M5 (M = Al, B and Cr) powders were synthesized by mechanical alloying in a planetary ballmill from high purity elemental powders. Evolution of non-equilibrium solid solutions of ?-Fe[Si,(Al, B, Cr)] with a nanocrystalline structure was accompanied by the introduction of a large number of dislocation defects in the course of the milling process. Fe sites get substituted by Si and M (M = Al, B, Cr) atoms during the milling process. The structural change and the resulting disorder are reflected in the changes in the lattice parameter and average magnetic moment of the powders milled for various time periods. The effective magnetic anisotropy increases linearly with the milling time. An increase in coercivity with increasing milling time was observed which could be attributed to the introduction of dislocations and the ...
Using the [sup 57]Fe Moessbauer spectroscopy, the microscopic behavior of Fe powders has been investigated during and after the mechanical alloying (MA) process for Al-Fe and Ag-Fe systems. A repeated rolling method as well as a conventional ball-milling method are employed in order to understand the microscopic process of the kneading of Al and Fe powders during their MA and the resultant powders show quite similar Moessbauer spectra suggesting that the kneading by an impact between colliding balls is the same process as that of the thickness reduction by cold rolling. Moessbauer spectra show clearly the occurrence of the mutual atomic dispersion for the thermodynamically immiscible Ag-Fe system. (orig.).
Effect of alcohol solvent in mixing process on process on the microstructure and sintering behavior of ceramic-based composites was inestigated in detail. The mixture of fine ceramic powders was prepared through the conventional ball-milling method with various alcohol media. The particle distributions of fine ceramic powders were strongly dependent on the kind of alcohol employed during ball-milling. Ceramic-based composites were fabricated by hot-pressing the mixture of fine ceramic powders. Their microstructures and some mechanical properties of the ceramic-based composites were evaluated. It was found that the viscosity of alcohol, surface tension and contat angle greatly affect the sinterbility and some of the mechanical properties of ceramic-based somposites. (author)
Nanocrystalline cemented tungsten carbide has attracted considerable interests for use in cutting tool because of its superior mechanical properties. In this study, nano-sized powders of mixed WC and Co were prepared from attrition-milled oxides by a gas reduction-carburization process. The effects of compacting pressure, heating schedule, additional ball-milling, and the presence of a grain growth inhibitor on the sintering properties of the nano-sized WC-Co powders were examined. The grain size and phases in WC-Co alloy were clearly affected by compacting pressure. Because of the trapped gases and the lower melting point of the cobalt binder, when a compact of nano-sized WC-Co powder was sintered through a heating schedule with holding steps, the sintered alloy maintained the small size of WC grains without any {eta} phase. In addition, the additional ball-milling improved the microstructure and mechanical properties of ...
Nanocrystalline cemented tungsten carbide has attracted considerable interests for use in cutting tool because of its superior mechanical properties. In this study, nano-sized powders of mixed WC and Co were prepared from attrition-milled oxides by a gas reduction-carburization process. The effects of compacting pressure, heating schedule, additional ball-milling, and the presence of a grain growth inhibitor on the sintering properties of the nano-sized WC-Co powders were examined. The grain size and phases in WC-Co alloy were clearly affected by compacting pressure. Because of the trapped gases and the lower melting point of the cobalt binder, when a compact of nano-sized WC-Co powder was sintered through a heating schedule with holding steps, the sintered alloy maintained the small size of WC grains without any #eta# phase. In addition, the additional ball-milling improved the microstructure and mechanical properties of ...
An experimental investigation was conducted to determine the feasibility of machining isogrid structures with abrasive-waterjets (AWJs). The main objective was to mill isogrid patterns in surfaces with accurate depth control using an AWJ. Three different approaches using AWJs were tested: linear cutting of isogrid patterns for diffusion bonding, milling with conventional AWJ nozzles, and milling with a single-angled rotary AWJ nozzle. It was shown that pocket milling with conventional AWJs is the most feasible of those tested. The milling can be done internally on preformed aluminum tubes, and the AWJ can also be used on materials other than aluminum. Accurate depth control can be achieved at high productivity rates. As an example, it is projected that a 48-inch-diameter skirt 12 inches high could be milled with an isogrid pattern in 6.3 ...
Fine-grained BaTiO3-based X7R ceramic materials were prepared and the effects of milling process on the core-shell structures and dielectric properties were investigated using scanning electron microscope, transmission electron microscope, and energy dispersive spectroscopy (EDS). As the milling time extends, the dielectric constant of the ceramics increases, whereas the temperature coefficient of capacitance at 125degreeC drops quickly. The changes in dielectric properties are considered relevant to the microstructure evolution caused by the milling process. Defects on the surface of BaTiO3 particles increase because of the effects of milling process, which will make it easier for additives to diffuse into the interior grains. As the milling time increases, the shell region gets thicker a...
The effects of catalytic metal additives on the hydrogen desorption properties of the submicrocrystalline magnesium hydride (#beta#-MgH_2) formed after hydrogenation of the Mg + 10 wt.%X (X = V, Y, Zr) mechanically (ball) milled composites were studied. The composites with catalytic metals were processed by controlled mechanical milling (CMM) in the magneto-mill Uni BallMill 5 under protective Ar atmosphere. X-ray diffraction of the milled powders revealed the formation of Mg nanograins (50-60 nm range) interdispersed with the nanograined metal additives within the powder particles. Scanning electron microscopy showed particle size reduction after milling. After activation and hydrogenation in a Sieverts-type apparatus under about 2 MPa pressure of hydrogen, the tetragonal #beta#-MgH_2 hydride co-exists with the small ...
We examined a catalytic effect of niobium oxide (Nb{sub 2}O{sub 5}) on the hydrogen storage properties of MgH{sub 2} prepared by mechanical ballmilling method. The MgH{sub 2} composite doped with 1 mol% Nb{sub 2}O{sub 5} by ballmilling for 20 h desorbed hydrogen up to {approx}6 mass% in the temperature range from 200 to 250 {sup o}C at the heating rate of 5 {sup o}C/min under a purified helium flow. After dehydrogenation at 200 {sup o}C, the product showed remarkable hydrogen absorption kinetics. A large amount of gaseous hydrogen up to {approx}4.5 mass% was absorbed even at room temperature under 1 MPa hydrogen pressure within 15 s and finally its capacity reached up to 5 mass%. Furthermore, the valence state of Nb{sub 2}O{sub 5} doped in MgH{sub 2} was examined by X-ray absorption near edge structure (XANES) measurement. The results indicated that additive Nb{sub 2}O{sub 5} was reduced by MgH{sub 2} ...
Nd{sub 40}Fe{sub 30}Al{sub 10}Co{sub 15}B{sub 5} alloys were fabricated by high energy ballmilling method under various conditions. Microstructure of the alloys was investigated by X-ray diffraction and electron microscopy techniques. Magnetic properties were characterized by hysteresis and thermomagnetic measurements. The high coercive fields up to 2.36 T have been observed on the samples consisting of Nd{sub 2}(Fe,Co,Al){sub 14}B, Nd{sub 6}(Fe,Co,Al){sub 14} and Nd crystallites imbedded in a residual amorphous matrix.
Together with an investigation on the deformation behavior of hot and cold rolled strip edge, the edge-drop control was explained in characteristics and result of application to the commercial mill by the tapered-crown work roll (WR) shifting mill. From a cold rolling experiment, three-dimensional material flow was known to be generated in the vicinity of edge also at the time of rolling the strip, and which generation influences that of edge-drop. Almost linearly relative to the flattened deformation of WR, the edge-drop enlarges with enlargement in that deformation. The number of stands to be applied to the tapered-crown WR shifting mill in the tandem cold mill is determined by the location as far as which the strip is to be controlled in edge-drop. In case of improving it to obtain the edge-drop-free strip, all the stands are required to be equipped with tapered-crown WR shifting ...
Composite particles represented as TiV{sub 2.1}Ni{sub 0.3}-Raney Ni(R) were prepared by ball-milling a TiV{sub 2.1}Ni{sub 0.3} alloy with Raney Ni in the presence of 0.01 M sodium hypophosphite (NaH{sub 2}PO{sub 2}) aqueous solution as a reducing agent. The composite particles had different morphology from original TiV{sub 2.1}Ni{sub 0.3} alloy particles and TiV{sub 2.1}Ni{sub 0.3}-Raney Ni composite particles prepared by the ball-milling in the absence of the NaH{sub 2}PO{sub 2} aqueous solution. In charge-discharge cycle tests, the TiV{sub 2.1}Ni{sub 0.3}-Raney Ni(R) composite electrode showed the maximum discharge capacity of 620 mAh g{sup -1}, while its cycle durability was similar to the TiV{sub 2.1}Ni{sub 0.3} alloy electrode, which was explained from depth profiles of constituent elements by Auger electron spectroscopy (AES). In thermogravimetry (TG) and differential thermal analysis (DTA), two steps of dehydriding for hydrided TiV{sub ...
Composite particles represented as TiV_2_._1Ni_0_._3-Raney Ni(R) were prepared by ball-milling a TiV_2_._1Ni_0_._3 alloy with Raney Ni in the presence of 0.01 M sodium hypophosphite (NaH_2PO_2) aqueous solution as a reducing agent. The composite particles had different morphology from original TiV_2_._1Ni_0_._3 alloy particles and TiV_2_._1Ni_0_._3-Raney Ni composite particles prepared by the ball-milling in the absence of the NaH_2PO_2 aqueous solution. In charge-discharge cycle tests, the TiV_2_._1Ni_0_._3-Raney Ni(R) composite electrode showed the maximum discharge capacity of 620 mAh g"-"1, while its cycle durability was similar to the TiV_2_._1Ni_0_._3 alloy electrode, which was explained from depth profiles of constituent elements by Auger electron spectroscopy (AES). In thermogravimetry (TG) and differential thermal analysis (DTA), two steps of dehydriding for hydrided TiV_2_._1Ni_0_._3-Raney Ni(R) composite started from much lower ...
Hydrogen storage alloy composites La{sub 0.7}Mg{sub 0.25}Zr{sub 0.05}(Ni{sub 0.85}Co{sub 0.15}){sub 3.5}(x=0,5,10) were prepared by ballmilling method. Their structures, morphologies and the hydrogen storage characteristics were intensively studied in the present work. It was found that the bulk of composites maintained the hexagonal C14 Laves phase structure after ballmilling with additional La-Mg-based alloy for two hours. Scanning electron microscopy (SEM) observations revealed that the average size of Ti{sub 0.9}Zr{sub 0.2}Mn{sub 1.5}Cr{sub 0.3}V{sub 0.3} and La{sub 0.7}Mg{sub 0.25}Zr{sub 0.05}(Ni{sub 0.85}Co{sub 0.15}){sub 3.5} particles were reduced to several hundred nanometers after ballmilling process. Energy dispersive X-ray spectrometer (EDS) patterns of the composites showed that the La{sub 0.7}Mg{sub 0.25}Zr{sub 0.05}(Ni{sub 0.85}Co{sub ...
Five nomographs have been prepared that facilitate the estimation of cover thickness and cover material volume for the Uranium Mill Tailing Remedial Action Program. Key parameters determined include the cover thickness with either a surface radon flux or a boundary radon air concentration criterion and the total volume of cover material required for two different treatments of the edge slopes. Also included in the engineering guide are descriptions and representative values for the radon source term, the diffusion coefficients and the key meteorological parameters. 16 refs., 7 figs., 2 tabs.
By treatment with beta or gamma rays, PTFE waste is converted to high-grade PTFE fine powder. High-molecular weight PTFE is degraded to low-molecular weight PTFE. Due to this the density, the degree of crystallinity, and the melt flow index are increased, which enhances the brittleness of the material. Irradiation of PTFE thus facilitates milling and makes the material pourable and free-flowing. Milled PTFE fine powder, lie PTFE plastic, combines temperature resistance, weather fastness, and chemical stability with good slip behaviour and antiadhesive properties. Areas of application for fine powder include additives for plastics, printing inks, nonstick coatings, and antifriction lacquers. (orig.).
Volume four contains calculations for: Borrow areas--site evaluation; temporary facilities--material quantities; embankment quantities--excavation and cover materials; Burro Canyon site excavation quantities--rippable and unrippable materials; site restoration--earthwork quantities and seeding; and bid schedule quantities and material balance.
In order to overcome the inherent disadvantages of Ti-V-based hydrogen storage alloys, such as poor activation behavior and low high-rate dischargeability, the novel composites Ti{sub 0.17}Zr{sub 0.08}V{sub 0.35}Cr{sub 0.1}Ni{sub 0.3}-x wt.% La{sub 0.7}Mg{sub 0.3}Ni{sub 2.75}Co{sub 0.75} (x = 0, 5, 10 and 20) were successfully synthesized by ballmilling method in the present study. And the structure and overall electrochemical properties of as-prepared composites are investigated systemically. The electrochemical studies show that the maximum discharge capacity of the composite electrodes displays no variation with the increase of La{sub 0.7}Mg{sub 0.3}Ni{sub 2.75}Co{sub 0.75} content, whereas the high-rate dischargeability (HRD) and the activation behavior are distinctly improved with increasing x. The electrochemical hydrogen kinetics of composite electrodes is also studied by means of electrochemical impedance spectroscopy (EIS), linear ...
Investigations of alternative renewable energy resources continue, with many studies concentrating on hydrogen storage. However, there are a few problems such as storage, transportation, delivery to the user and usage safely, to be addressed to facilitate commercialization and wide usage of the hydrogen. The absorbed form within the metal hydrides seems to be the best solution of this problem. Since Li is the lightest metal, it has the advantage as the stored amount of hydrogen mass ratio. LiBH{sub 4} production process was investigated using elemental Li, B and H{sub 2}. Spex type ballmilling with tungsten carbide, stainless steel and zirconia type vessels, was used to mix the different amount of Li and B under argon atmosphere. X-ray diffraction pattern demonstrated that the LiB was obtained. A system was designed to provide a hydrogen atmosphere of 60 bars to force hydrogen into the LiB structure. FTIR analysis strongly indicated the ...
This document describes the results of accelerated aging tests to determine the long-term effectiveness of selected impoundment liner materials in a uranium mill tailings environment. The study was sponsored by the US Department of Energy under the Uranium Mill Tailings Remedial Action Project. The study was designed to evaluate the need for, and the performance of, several candidate liners for isolating mill tailings leachate in conformance with proposed Environmental Protection Agency and Nuclear Regulatory Commission requirements. The liners were subjected to conditions known to accelerate the degradation mechanisms of the various liners. Also, a test environment was maintained that modeled the expected conditions at a mill tailings impoundment, including ground subsidence and the weight loading of tailings on the liners. A comparison of installation costs was also performed for ...
Thinning specimens to electron transparency for electron microscopy analysis can be done by conventional (2-4 kV) argon ion milling or focused ion beam (FIB) lift-out techniques. Both these methods tend to leave 'mottling' visible on thin specimen areas, and this is believed to be surface damage caused by ion implantation and amorphisation. A low energy (250-500 V) Argon ion polish has been shown to greatly improve specimen quality for crystalline silicon samples. Here we investigate the preparation of technologically important materials for nanoanalysis using conventional and lift-out methods followed by a low energy polish in a GentleMill"T"M low energy ion mill. We use a low energy, low angle (6-8 deg.) ion beam to remove the surface damage from previous processing steps. We assess this method for the preparation of technologically important materials, such as steel, silicon and ...
The objective of the investigation was to study the feasibility of applying continuous casting steel 100Cr6 (SAE 52100) for bearing balls. It was found that two of three continuous casted steel batches have longer or at least similar rolling contact fatigue lifetimes compared to one ingot casted batch. For one of the continuous casted batches, the rolling contact fatigue lifetime was 30% less. The micro- and macrostructure and the residual stresses below the surface of the balls were comparable. There is also no obvious difference between the four batches in the metallurgical parameters like contents of oxygen, titanium and sulfur as well as in the distribution of carbides and their network. The reason for the shorter lifetime of one batch finally was found to be due not to the continuous casting process itself. There was a difference in the cross section of the different casting moulds, and by this in the speed of solidification. As a ...
The instrument ball bearings are the key components of movable components for various kinds of measuring and control instruments; they often operate in the environmental condition of high-speed and light preload. In general, the non metal, disposable oilimpregnated retainer material has been used for these kinds of high precision miniature bearing. The engineering practice shows that the common failure mode of them is the wear which appears under the condition of insufficient lubrication condition. As the results, the vibration and noise will be enlarged, so does the frictional torque, which makes the ball bearings to lose its original working accuracy. It is the lifetime test of bearings that can enable the designers and manufacturers to chose the material of the bearing properly, optimize the product structure, mend the manufacturing technique process, and to enhance the technical level of the bearing ...
Low-porosity #alpha#- and #beta#-SiAlON composite material was prepared when the powder mixture intended for preparation of yttrium #alpha#-SiAlON, with the formula Y_0_._4Si_1_2_-_m_+_nAl_m_+_nO_nN_1_6_- _n, was attritor milled in isopropyl alcohol or contained excess oxygen (n > 0.6). The region of stability of single-phase yttrium #alpha#-SiAlON was smaller at lower temperatures. Wet milling (in isopropyl alcohol) of AlN powder was found to introduce excess oxygen into the milled powder.
In this work, the effects of the focus ion beam (FIB) milling process on the optical properties of semiconductor nanostructures were investigated. With this aim, a sensitive materials system based on InGaAs/GaAs quantum dots with well known and excellent optical properties was selected for the FIB treatment. The FIB technique was used to locally remove a metallic mask deposited on top of the quantum dot sample. The photoluminescence (PL) signal, collected from the circular openings, was used to infer the possible damage effects of the ion beam on the properties of the dots.
Amorphous materials in the system xLi{sub 2}S{center_dot}(100-x)SiS{sub 2}, where x ranged from 50 to 70 mol %, and (100-y) (0.6Li{sub 2}S{center_dot}0.4SiS{sub 2}){center_dot}yLi{sub 4}SiO{sub 4}, where y ranged from 0 to 10 mol %, were synthesized by mechanical milling of crystalline starting materials, Li{sub 2}S, SiS{sub 2} and Li{sub 4}SiO{sub 4}. At the compositions with large amounts of Li{sup +} ions, a part of crystalline Li{sub 2}S used as a starting material remained in the milled powder samples. It was found that the milled powder samples in both systems obtained by mechanical milling exhibited high conductivities in the order of 10{sup -4}S{center_dot}cm{sup -1} at room temperature in spite of the presence of small amounts of Li{sub 2}S crystals. The conductivity values of the pelletized samples of xLi{sub ...
A focused ion beam (FIB) is used to accurately sculpt predetermined micron-scale, curved shapes in a number of solids. Using a digitally scanned ion beam system, various features are sputtered including hemispheres and sine waves having dimensions from 1-50 {micro}m. Ion sculpting is accomplished by changing pixel dwell time within individual boustrophedonic scans. The pixel dwell times used to sculpt a given shape are determined prior to milling and account for the material-specific, angle-dependent sputter yield, Y({theta}), as well as the amount of beam overlap in adjacent pixels. A number of target materials, including C, Au and Si, are accurately sculpted using this method. For several target materials, the curved feature shape closely matches the intended shape with milled feature depths within 5% of intended values.
There is currently great interest in combining focused ion beam (FIB) and scanning electron microscopy technologies for advanced studies of polymeric materials and biological microstructures, as well as for sophisticated nanoscale fabrication and prototyping. Irradiation of electrically insulating materials with a positive ion beam in high vacuum can lead to the accumulation of charge, causing deflection of the ion beam. The resultant image drift has significant consequences upon the accuracy and quality of FIB milling, imaging and chemical vapour deposition. A method is described for suppressing ion beam drift using a defocused, low-energy primary electron beam, leading to the derivation of a mathematical expression to correlate the ion and electron beam energies and currents with other parameters required for electrically stabilizing these challenging materials.
Volume one contains calculations for: embankment design--embankment material properties; Union Carbide site--bedrock contours; vicinity properties--origin of contamination; North Continent and Union Carbide sites contaminated materials--excavation quantities; and demolition debris--quantity estimate.
This paper introduces a new method to produce nano-composite powder for the preparation of high performance ZnO varistors. ZnO particles were coated with Bi{sub 2}O{sub 3}, Sb{sub 2}O{sub 3}, Co{sub 2}O{sub 3}, Cr{sub 2}O{sub 3} and other additives via liquid nano-coating technique. Then the prepared powder was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravity and differential scanning calorimetry (TG-DSC) and particle size distribution. The results showed that the ZnO composite powder is homogeneously coated and ultrafine. The densification, phase composition and microstructure of ZnO varistors was studied by linear shrinkage, X-ray diffraction (XRD) and SEM, respectively. The preliminary electrical parameters of ZnO varistors showed that the breakdown voltage V {sub b} (1 mA/cm{sup 2}) and nonlinear coefficient {alpha} is 5400 V/cm and 50, respectively, much higher than that of conventional ball ...
The nanocomposite WC-Co powders were prepared through planetary ballmilling method. Effects of grain growth inhibitor addition and the vacuum sintering parameters on the microstructure and properties of ultrafine WC-10Co cemented carbides were investigated using X-ray diffractometer, scanning electron microscope and mechanical property tester. The results show that VC and NbC additions can refine the WC grains, decrease the volume fraction of Co3W3C phase in ultrafine WC-10Co cemented carbides, and increase the hardness and fracture toughness of the base alloys. After sintering for 60 min at 1400 degreeC, the average grain size and hardness of ultrafine-grained WC-10Co-1VC cemented carbide are 470 nm and HRA 91.5, respectively. The fracture toughness of cemented carbide WC-10Co-1NbC alloy...
Borohydrides such as LiBH{sub 4} have been studied as candidates for hydrogen storage because of their high hydrogen contents (18.4 wt% for LiBH{sub 4}). Limited success has been made in reducing the dehydrogenation temperature by adding reactants such as metals, metal oxides and metal halides. However, full rehydrogenation has not been realized because of multi-step decomposition processes and the stable intermediate species produced. It is suggested that adding second cation in LiBH{sub 4} may reduce the binding energy of B-H. The second cation may also provide the pathway for full rehydrogenation. In this work, several bimetallic borohydrides were synthesized using wet chemistry, high pressure reactive ballmilling and sintering processes. The investigation found that the thermodynamic stability was reduced, but the full rehydrogenation is still a challenge. Although our experiments show the partial reversibility of the bimetallic ...
This paper evaluates the performance of asphalt membranes by examining the chemical and permeability changes experienced by the asphalt during aging tests. The aging process was accelerated by exposing the asphalt to elevated temperatures, high oxygen concentrations, and increased strengths of aqueous oxidizing agents. The synergistic effects of the variables are evaluated by using a fractional factorial experimental design. The installation costs for a catalytically airblown asphalt liner are roughly half that of the typical polymeric materials, and also less than the rubberized asphalt membrane. The results of the initial accelerated aging tests of the asphalt membranes indicate that this material will provide stable, long-term leachate isolation in a mill tailings environment.
An x-ray zone plate was fabricated using the novel approach of focused ion beam (FIB) milling. The FIB technique was developed in recent years, it has been successfully used for transmission electron microscopy (TEM) sample preparation, lithographic mask repair, and failure analysis of semiconductor devices. During FIB milling, material is removed by the physical sputtering action of ion bombardment. The sputter yield is high enough to remove a substantial amount of material, therefore FIB can perform a direct patterning with submicron accuracy. The authors succeeded in fabricating an x-ray phase zone plate using the Micrion 9500HT FIB station, which has a 50 kV Ga{sup +} column. Circular Fresnel zones were milled in a 1.0-{micro}m-thick TaSiN film deposited on a silicon wafer. The outermost zone width of the zone plate is 170 nm at a radius of 60 {micro}m. An achieved aspect ratio ...
This regulatory guide describes methods acceptable to the NRC staff for calculating radon fluxes through earthen covers and for calculating the resulting minimum cover thickness needed to meet NRC and EPA standards. The guide also suggests methods for obtaining the various parameters used in calculating the radon fluxes and earthen cover thicknesses and suggests default values for certain parameters. This regulatory guide is applicable to active uranium tailings sites. The NRC staff is using the methods stated in this guide as a basis for review and concurrence of DOE remedial action plans for inactive sites. The guidance is intended to be used for calculating radon flux attenuation by earthen uranium mill tailings covers. The parameter values and examples presented are limited to earthen cover materials, but the diffusion theory and the methods presented are also applicable to man-made materials. Detailed supporting ...
This regulatory guide describes methods acceptable to the NRC staff for calculating radon fluxes through earthen covers and for calculating the resulting minimum cover thickness needed to meet NRC and EPA standards. The guide also suggests methods for obtaining the various parameters used in calculating the radon fluxes and earthen cover thicknesses and suggests default values for certain parameters. This regulatory guide is applicable to active uranium tailings sites. The NRC staff is using the methods stated in this guide as a basis for review and concurrence of DOE remedial action plans for inactive sites. The guidance is intended to be used for calculating radon flux attenuation by earthen uranium mill tailings covers. The parameter values and examples presented are limited to earthen cover materials, but the diffusion theory and the methods presented are also applicable to man-made materials. Detailed supporting ...
The Maybell uranium mill tailings site is 25 miles (mi) (40 kilometers [km]) west of the town of Craig, Colorado, in Moffat County, in the northwestern part of the state. The unincorporated town of Maybell is 5 road mi (8 km) southwest of the site. The designated site covers approximately 110 acres (ac) (45 hectares [ha]) and consists of a concave-shaped tailings pile and rubble from the demolition of the mill buildings buried in the former mill area. Contaminated materials at the Maybell processing site include the tailings pile, which has an average depth of 20 feet (ft) (6 meters [m]) and contains 2.8 million cubic yards (yd{sup 3}) (2.1 million cubic meters [m{sup 3}]) of tailings. The former mill processing area is on the north side of the site and contains 20,000 yd{sup 3} (15,000 m{sup 3}) of contaminated demolition debris. Off-pile contamination is present and includes areas ...
A method is described for determining the particulate contamination in miniature ball bearings in which the bearing is flushed with a solvent that is then filtered. The particles that are collected on the filter are examined by optical microscopy.
This volume contains appendices D6 through D8 containing laboratory test data: from MK-F investigation, 1987, Old Rifle and New Rifle sites; on bentonite amended radon barrier material; and from MK-F investigation, 1987, riprap tests.
The durability of ball bearings, 32-mm- and 45-mm-bore, with a retainer or glass cloth-polytetrafluoroethylene (PTFE) laminate was tested under a high radial load at a speed of 20,000 rpm in LOX or LN2. The retainers were characterized as good self-lubricators because the abrasive glass-cloth fiber tips exposed on the retainer were chemicaly etched away with hydrofluoric acid (HF). During testing, the bearing-cartridge-acceleration was monitored to detect bearing damage. Testing in LOX for about 2.2 hr showed that excellent lubricating conditions were obtained for all bearings. Testing in LN2 for about 5.1 hr detected that the fatigue life of the bearing was about the same as the calculated B10 fatigue life. The HF chemical treatment resulted in a reacted fluoride-oxide material which remained in the etched part of the glass fiber. Several chemical products, particularly MgO, CaO, and CaCO3, enhanced adhesion of PTFE transfer film to the ...
The US NRC, in its Generic Environmental Impact Statement on uranium milling has specified that the radon flux escaping a uranium mill tailings pile will be reduced to pCi/m/sup 2/ s by application of covering layers of soils and clays. These covers present a radon diffusion barrier, which sufficiently increases the time required for radon passage from the tailings to the atmosphere to allow for decay of /sup 222/Rn within the cover. The depth of cover necessary to reduce the escaping radon flux to the prescribed level is to be determined by calculation, and requires precise knowledge of the radon diffusion coefficient in the covering media. A Radon Attenuation Test Facility was developed to determine rates of radon diffusion through candidate cover materials. This paper describes this facility and its application for determining the influence of physical properties of the soil column on the radon diffusion coefficient.
The high-nickel austenitic alloy 800 (in both the mill-annealed and the solution-treated grades) has several attractive properties that make it a good candidate for service attractive properties that make it a good candidate for service at elevated temperatures in corrosive environments. One such property is creep resistance. This report analyzes the elevated-temperature creep behavior of the mill-annealed grade, generally referred to simply as alloy 800. (The solution-treated grade is known as alloy 800H). Available data over the temperature range from 538 to 760/sup 0/C were collected and evaluated to yield mathematically approximations for creep-rupture and strain-time behavior for use in design calculations. However, the creep behavior of this material is extremely complex, and the analysis presented here contains substantial uncertainties. All results in this report should be considered preliminary because of limited ...
Focused Ion Beam (FIB) milling is a powerful tool to produce ordered magnetic nanostructures. However, it is impossible to produce out-of-plane magnetized nanoscale structures from multilayer films by direct FIB writing. Co/Pt multilayers exhibit an out-of-plane easy axis due to strong perpendicular interface anisotropy. The interface contribution is known to be very sensitive to high energy ion irradiation. In case of 30 keV Ga ions it needs less than one ion per 100 surface atoms to destroy the perpendicular interface anisotropy. We demonstrate how this problem can be overcome by milling a Co/Pt multilayer, which has been deposited on a SiN membrane, from the rear side, through the SiN. The effect of the ions is determined as a function of applied dose utilizing the domain structure imaged by soft X-ray holography. When the magnetic material is removed we find only a very narrow range of destruction around the holes in ...
Intermetallic compounds based on the Al-Co system were synthesized by solid state method - mechanical alloying and their properties were investigated using XRD, SEM, and DSC. The powder was used to make new targets of irradiation for gamma sources in order to enhance the specific activity and to reduce the consumption of material. The intermetallic compound AlCo was formed in the first 4 hours of milling. After 8 hours of milling the medium size of crystallites were of 5.58 nm. This value decreases with the increase of milling time up to 3 nm, corresponding to the 28 hours of grinding. There was calculated and plotted the Gibbs function, #DELTA#_f"0, for the reaction of formation AlCo and Al_3Co from the Al-Co system. It had negative values over the entire range of temperatures for both investigated compounds. After 28 hours milling a phase composition was obtained as follows: 0.2% ...
The Sputter coefficient of accelerated CO{sub 2} cluster ions hitting surfaces of various materials is investigated. For copper it varies proportional to the 2nd power of the energy between 155 and 260 keV. The rate of erosion for different target materials varies by two orders of magnitude from tungsten to PMMA. Diamond is eroded fairly quickly, while aluminum is eroded less than corundum (Al{sub 2}O{sub 3}). No simple correlation of the sputter coefficient on the bulk material properties is found. For copper the angular distribution of sputtered material is measured and found to be following roughly a cosine distribution. By using masks different microstructures have been produced in cobalt-samarium magnets, diamond and glass. (orig.)
The main purpose of solid or fluid lubricants in ball-bearings is to separate the balls and races from contacting each other in so-called asperity collisions. Steel to steel contacts lead to microwelds which roughen functional rolling-contacting surfaces and deteriorate the lubricant. By using balls with a ceramic TiC coating, two goals are achieved. First, there are fewer asperity collisions because of the extreme smoothness of the high precision polished TiC coated balls. Second, if collisions do occur, there is practically no microwelding taking place, leaving the surfaces and the lubricant in good condition. Examples are given where the bearing lifetime is increased up to 10 times if the steel balls are replaced by TiC-coated balls. (orig.).
The Maybell uranium mill tailings site is 25 miles (mi) (40 kilometers [km]) west of the town of Craig, Colorado, in Moffat County, in the northwestern part of the state. The unincorporated town of Maybell is 5 road mi (8 km) southwest of the site. The site is 2.5 mi (4 km) northeast of the Yampa River on relatively flat terrain broken by low, flat-topped mesas. U.S. Highway 40 runs east-west 2 mi (3.2 km) south of the site. The designated site covers approximately 110 acres (ac) (45 hectares [ha]) and consists of a concave-shaped tailings pile and rubble from the demolition of the mill buildings buried in the former mill area. The site is situated between Johnson Wash to the east and Rob Pit Mine to the west. Numerous reclaimed and unreclaimed mines are in the immediate vicinity. Aerial photographs (included at the end of this executive summary) show evidence of mining activity around the Maybell site. Contaminated ...
We investigate ordering properties of two-dimensional granular materials using several shapes created by welding ball bearings together. Ordered domains form much more easily in two than in three dimensions, even when configurations lack long-range order. The onset of ordered domains occurs near a packing density of 0.8, a phenomenon observed previously for disks. One of our shapes, the trapezoid, has packings that remain disordered and near the transition density even after annealing by shaking. Although random packings are unstable for disks and many other shapes in two dimensions, trapezoid packings provide an approach to studying two-dimensional randomness. We also find that the rotational symmetry of a shape is an excellent predictor of how easily it orders, and a potential guide to identifying two-dimensional shapes that remain random after annealing.
The dependence was determined of the decontamination factor ratio found in the presence of a carrier and in a carrier-free system on carrier concentration at different concentrations of a complexing agent in a solution. Bearing balls were used as contamination materials while a mixture of "1"5"2Eu and "1"5"4Eu isotopes was used as a contaminant, citric acid in a concentration of 5x10"-"3 to 1x10"-"1 mol/dm"3 as a complexing agent, and Eu, lanthanum and aluminium at a concentration range of 1x10"-"5 to 1x10"-"2 mol/dm"3 as carriers. While no increase in the decontamination factor was found for aluminium, a considerable increase was observed in the isotopic and homologic carriers and the concentration dependence of the carrier reached the maximum. An equation was derived explaining the effect by the isotope exchange between the contaminant and the carrier and by the reaction between the carrier and the complexing agent. (J.F.).
Superalloys, such as Inconels and Incoloys, are extensively used where high strength is a requirement. However, where these materials are required to slide against one another, particularly with poor or no lubrication, high friction levels and seizure are commonly seen to occur, which can cause component failure. In this work seizure characteristics of three superalloys (Inconel 718 and Incoloys 945 and 945X) were investigated, uncoated, coated with Armoloy (a hard, thin, dense chrome coating with a micro-nodular surface texture) and plasma nitrided in dry sliding conditions. A rig purpose built for initiating seizure was used. It involves sliding a ball against a disc at constant speed while the load is increased. Tests are designed to last less than one rotation so that the wear scar can...
Focused ion beam (FIB) milling is a powerful and versatile tool for the maskless fabrication of structures and devices at micro- and nanometer scales. The approach is based on the milling and deposition capabilities of a focused ion beam, where the latter is achieved by ion-beam-assisted decomposition of a metalorganic gas precursor of the specific material that has to be deposited. The combination of FIB and scanning electron microscopy in the same unit (so-called dual-beam unit) further expands the capabilities of the approach by the possibility of performing electron-beam-assisted deposition and inspection. Permalloy nanowires with electrical contacts patterned by FIB-Pt deposition were prepared in the dual-beam unit. Various types of notches to pin magnetic domain walls were additionally fabricated by means of FIB. The fabrication parameters for a structural modification of the Permalloy structures without too strongly ...
The plastic displacements around Knoop indentations made in hard titanium/aluminum multilayered films on soft aluminum alloy substrates have been studied. Indentations were cross-sectioned and imaged using the focused-ion-beam (FIB) milling and high-resolution scanning electron microscopy (SEM), respectively. The FIB milling method has the advantage of removing material in a localized region without producing mechanical damage to the specimen. The micrographs of the cross-sectioned indentations indicate that most of the plastic deformation around the indentation is dominated by the soft aluminum substrate. There is a very small change in the multilayered film thickness around the indentation{emdash}less than 10{percent}. The plastic deformation of the thin film resembles a membrane being deflected by a localized pressure gradient across the membrane. Stress-induced voids are also observed in the multilayered film, ...
This Resource Letter provides a guide to the literature on Quantum Chromodynamics (QCD), the relativistic quantum field theory of the strong interactions. Journal articles, books, and other documents are cited for the following topics: quarks and color, the parton model, Yang-Mills theory, experimental evidence for color, QCD as a color gauge theory, asymptotic freedom, QCD for heavy hadrons, QCD on the lattice, the QCD vacuum, pictures of quark confinement, early and modern applications of perturbative QCD, the determination of the strong coupling and quark masses, QCD and the hadron spectrum, hadron decays, the quark-gluon plasma, the strong nuclear interaction, and QCD's role in nuclear physics. The letter {E} after an item indicates elementary level or material of general interest to persons becoming informed in the field. The letter {I}, for intermediate level, indicates material of a somewhat more specialized nature, ...
In this paper, a complete solution of the steady-state Newton-Euler equations describing the motion of the balls in high speed thrust bill bearings is presented. Kinematic equations are derived and used as ancillary equations to obtain the numerical solution of the Newton-Euler equations. This differs from previously reported work where extraneous assumptions (instead of kinematic analysis) are used to allow solutions of these equations. It is shown that the no-slip condition for the ball motion reported in the literature is based on an unnecessary assumption. The correct form of the condition is developed and used in the analysis of the ball motion. The analysis shows the importance of contact angle on both ball motion and contact force. An approximate theory is then developed for determining the optimum contact angle that would result in minimum contact force in high speed ball ...
LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} was prepared through a solid-state reaction using various Ni precursors. The effect of precursors on the electrochemical performance of LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} was investigated. LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} made from Ni(NO{sub 3}){sub 2}.6H{sub 2}O shows the best charge-discharge performance. The reversible capacity of LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} is about 145 mAh g{sup -1} and remained 143 mAh g{sup -1} after 10 cycles at 3.0-5.0 V. The XRD results showed that the precursors and the dispersion methods had significant effect on their phase purity. Pure spinel phase can be obtained with high energy ball-milling method and Ni(NO{sub 3}){sub 2}.6H{sub 2}O as precursor. Trace amount of NiO and Li{sub 2}MnO{sub 3} phase were detected in LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} with manual-mixture method and using Ni(CH{sub 3}COO){sub 2}.6H{sub 2}O, NiO and Ni{sub 2}O{sub 3} as precursors. (author)
Six intermetallic alloys (CeNi/sub 5/, MmNi/sub 5/, Ca/sub 0/ /sub 2/(Ce/sub 0/ /sub 65/Mm/sub 0/ /sub 35/)/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Ce/sub 0/ /sub 8/Ni/sub 5/, Ca/sub 0/ /sub 2/Mm/sub 0/ /sub 8/Ni/sub 5/, and a mixed alloy, CeNi/sub 5//MmNi/sub 5/) were investigated with respect to their suitability to provide high hydrogen capacity and their potential for use in providing substantial hydrogen pressure at both low and high temperatures. A second phase of our investigation dealt with ball-milling and hydriding and dehydriding cycles to produce fine particles for use in hydride powder transfer studies. A summary of several Van't Hoff plots is also included for hydride-forming alloys.
Part 2 of this manual provides the electric utility engineer with detailed technical information on some of the major mechanical equipment used in the FGD system. The objectives of Part 2 are the following: to provide the electric utility engineer with information on equipment that may be unfamiliar to him, including ballmills, vacuum filters, and mist eliminators; and to identify the unique technique considerations imposed by an FGD system on more familiar electric utility equipment such as fans, gas dampers, piping, valves, and pumps. Part 3 provides an overview of the recommended procedures for evaluating proposals received from FGD system vendors. The objectives are to provide procedures for evaluating the technical aspects of proposals, and to provide procedures for determining the total costs of proposals considering both initial capital costs and annual operating and maintenance costs. The primary objective of Part 4 of this manual is ...
This paper consists of shielding analysis of steel balls and water filled end shields of Indian Pressurized Heavy Water Reactors (PHWRs). The material composition inside lattice tube is entirely different neutronically as compared with the composition of end-shield. Due to variation of material composition in radial and axial directions and complex geometry, it is necessary to carry out 3-D analysis for reasonable prediction of neutron flux and gamma dose rates. In the present paper, shielding analysis of end-shield for 540 MWe PHWR has been carried out during reactor operating and shutdown conditions using Monte-Carlo code MCNP. Furthermore materials on the periphery and central portion of end shield are different. Therefore the analysis was carried out separately for annular portion and central portion of end shield. The dominating streaming paths through end shields were studied. Predictions compare ...
Generalized dynamic motion of balls and cage in a ball bearing are simulated by solving the differential equations of motion under prescribed operating conditions and bearing geometry. The general cage motion is parametrically evaluated as a function of clearances both in the ball pockets and at the guide lands. The design significance of the modeling approach is demonstrated by the prediction of critical clearances which trigger certain instabilities in the cage motion. In more practical terms, the correlation between cage clearances and instability defines a wear life for the bearing under the prescribed operating conditions. 10 refs.
The model of the supersymmetrical ball in the supersymmetrical Standard Model with additional global U(1) fermion symmetry is presented. We show that the supersymmetry breaking scale (R-parity), the global U(1) fermion symmetry scale and the electroweak symmetry breaking scale are strictly connected to each other. The realistic ball with M[approx]10[sup 5]-10[sup 9] M[sub s]un and the radius R[approx]10[sup 12]-10[sup 14] cm is obtained. Inside the ball all full symmetries are restored. The ball is stabilized by superpartners and right neutrinos which are massless inside. (orig.)
Many investigations of anode materials for lithium-ion secondary batteries have been carried out in order to obtain batteries of higher capacity and energy density. Recently, SnO-based glasses, which were prepared by the usual melt quenching technique, have been proposed as a new anode for lithium-ion secondary batteries by Idota et al. It has been reported that the capacity per unit weight was higher than 600 mAh g{sup {minus}1} and the capacity per unit volume was higher than 2,200 mAh cm{sup {minus}3}, values which are almost double those for carbon materials used as anodes of commercial lithium-ion batteries at present. Thus SnO-based glasses have attracted much interest as high-capacity anode materials for lithium-ion secondary batteries. Amorphous materials in the system SnO-B{sub 2}O{sub 3}-P{sub 2}O{sub 5}, with or without the addition of Li{sub 2}O, were synthesized by mechanical ...
This paper deals with preparation of PE clay nano composite specimen for transmission electron microscopy (TEM) and studying the difference between dispersion of clay in low density polyethylene using poly(hydrogen methyl siloxane) (PHMS) as coupling agent and untreated one. Argon ion milling is the conventional means by which film sections are thinned to electron transparency for TEM analysis, but this technique exhibits significant problems. In particular, selective thinning and imaging of sub-micrometer inclusions during sample milling are highly problematic. We have achieved successful results using the focused ion beam (FIB) lift-out technique, which utilizes a 30 kV Ga"+ ion beam to extract electron transparent specimens with nanometer scale precision. Using this procedure, we have prepared a number of thin film materials representing a range of structures and compositions for TEM analysis. We believe that FIB ...
Progress is reported on: radon barrier systems for uranium mill tailings; liner evaluation for uranium mill tailings; revegetation/rock cover for stabilization of inactive U-tailings sites; and application of long-term chemical biobarriers for uranium tailings.
A high-precision Li isotope analysis was developed for determining the Li"+ ion emitted from lithium phosphate as an ion source material by a Re double-filament ionization method in the thermal ionization mass spectrometry. In this method, Li isotopic fractionation is distinctly less sensitive to the filament temperature than those in the previous methods, and stable and high ion beam intensity of more than 8 x 10"-"1"1 A for "7Li is obtained. These advantages in determining the "7Li/"6Li ratio result in the analytical reproducibility of 0.26 per mille (1#sigma#). Furthermore, the sample preparation is simple and the low temperature (850degC) required by this method ensures the analysis of the isotopic composition of small amounts of Li with less influence of Li contamination to the sample, compared with the previous methods. (author).
As a result of nuclear power plant accidents, large areas receive radioactive inputs of Cs-137. This cesium accumulates in herbs growing in such territories. The problem is whether the herbs contaminated by radiocesium may be used as a raw material for medicine. The answer depends on the amount of Cs-137 transfered from the contaminated raw material to the medicine. We have presented new results of the transfer of Cs-137 from contaminated Digitalis grandiflora Mill. and Convallaria majalis L. to medicine. We found that the extraction of Cs-137 depends strongly on the hydrophilicity of the solvent. For example 96.5%(vol.) ethyl alcohol extracts less Cs-137 (11.6%) than 40%(vol.) ethyl alcohol or pure water (66.2%). The solubility of the cardiac glycosides is inverse to the solubility of cesium, which may be of use in the technological processes for manufacturing ecologically pure herbal medicine.
Due to the well-establish corrosion problems of Alloy 600 as a steam-generator material and the subsequent focus on thermally treated (TT) Alloy 690 and Alloy 800 as alternative materials, a systematic analysis of the corrosion behavior of these two latter alloys is warranted. Corrosion test results for Alloys 690 TT and 800 were collected and organized in the form of corrosion mode diagrams. Selected data for mill annealed (MA) Alloy 600 were also included for reference. The corrosion mode diagrams correlate the modes of corrosion degradation observed in tests as functions of the environment pH and electrochemical potential (ECP). The diagrams confirm that Alloys 690TT shows some susceptibility in caustic environments, and Alloy 800 shows susceptibility in both caustic and highly acidic environments. (authors). 6 figs., 5 refs.
Due to the well-establish corrosion problems of Alloy 600 as a steam-generator material and the subsequent focus on thermally treated (TT) Alloy 690 and Alloy 800 as alternative materials, a systematic analysis of the corrosion behavior of these two latter alloys is warranted. Corrosion test results for Alloys 690 TT and 800 were collected and organized in the form of corrosion mode diagrams. Selected data for mill annealed (MA) Alloy 600 were also included for reference. The corrosion mode diagrams correlate the modes of corrosion degradation observed in tests as functions of the environment pH and electrochemical potential (ECP). The diagrams confirm that Alloys 690TT shows some susceptibility in caustic environments, and Alloy 800 shows susceptibility in both caustic and highly acidic environments. (authors). 6 figs., 5 refs.
Pacific Northwest Laboratory (PNL) is investigating the use of a rock armoring blanket (riprap) to mitigate wind and water erosion of an earthen radon suppression cover applied to uranium mill tailings. Because the radon suppression cover and the tailings must remain intact for up to 1000 years or longer, the riprap must withstand natural weathering forces. This report is a review of information on rock weathering and riprap durability. Chemical and physical weathering processes, rock characteristics related to durability, climatic conditions affecting the degree and rate of weathering, and testing procedures used to measure weathering susceptibilities have been reviewed. Sampling and testing techniques, as well as analyses of physical and chemical weathering susceptibilities, are necessary to evaluate rock durability. Many potential riprap materials may not be able to survive 1000 years of weathering. Available techniques for durability ...
Nanoindentation was performed on a Mo-alloy single crystal to investigate effects of focused ion beam (FIB) milling on mechanical behavior. On a non-FIB-milled surface, pop-ins were observed on all load-displacement curves corresponding to a transition from elastic to plastic deformation. Similar pop-ins were not detected on surfaces subjected to FIB milling. This difference indicates that FIB milling introduces damage that obviates the need for dislocation nucleation during subsequent deformation. A second effect of FIB milling is that it increased the surface hardness. Together, these effects could be the source of the size effects reported in the literature on micropillar tests.
A strong necessary condition is given for the principal stabiliser of the action of a compact Lie group to have a non-zero centre. An application to the monopole problem in Yang-Mills-Higgs models is discussed.
The Yang-Mills equations are formulated in the form of generalized Maurer-Cartan equations, such that the corresponding algebraic operations are shown to satisfy the defining relations of homotopy Lie superalgebra.
During rolling contact fatigue of the inner rings of ball bearings three stages of material response can be distinguished, in terms of the volume that is plastically deformed upon overrolling. After a first stage of material strengthening during which a decrease occurs for the volume that is deformed plastically, an effectively stationary, second stage is entered which is eventually succeeded by a third stage exhibiting a pronounced increase of the volume that is deformed plastically upon overrolling, which leads to failure. It is suggested that carbon diffusion induced by local temperature peaks occurring at the moment of overrolling is the key mechanism leading to fatigue damage. The amount of decomposed retained austenite is a useful, practical parameter to assess fatigue life. It is shown that published ideas about the role of certain components of residual stress in enhancing fatigue life are not correct and that the ...
PVD-chromium-nitride coated samples of substrates of the magnesium alloy AZ91hp and the roller and ball bearing steel 100Cr6 were investigated regarding structure, mechanical characteristics, adhesion and internal stresses. For the coatings the parameters layer thickness and substrate BIAS voltage were varied. Both substrate materials were coated in one lad. Results of the X-ray analysis of the internal stresses show significant differences between the coated magnesium and the coated steel substrates. In the case of the variation of the substrate BIAS voltage, for the coated steel a dependency of the internal stresses to coating parameters could be obtained. For the coated magnesium no dependency was recognizable. The coating structure was examined with scanning electron microscopy. Element depth profiles of the coated samples were performed with SIMS. (orig.)
This report describes the 5 tasks to be covered under this project and compiles budget information. Task 1 is to establish a Plutonium Information Resource, which has been established in Amarillo, Texas. Task 2, Advisory Functions, coordinates studies and activities relating to the disposition of excess weapons-grade plutonium. Task 3, Environmental, Public Health, and Safety, supports soil remediation activities. Task 4, Education and Outreach, is supporting four programs: K--12 education improvement in science and math courses; Academic intervention to identify and encourage high ability high school and middle school students with potential to become scientists and engineers; Graduate education evaluation; and Public outreach programs. Task 5, Plutonium and other Materials Studies, is currently funding two projects for the disposition of high explosives: a feasibility study of burning a mixture of high explosives and other materials in a ...
This paper describes the experimental results of long-life solid lubricated ball bearings tested under high-vacuum of 10 exp -4 Pa, high-temperature of 300 C, and high-speed (9000 rpm) conditions. For full ball-type bearings, the thin soft metals, either Ag or Pb, which were coated on the races and balls, appeared to have good torque properties. However, the durability of such bearings was less than 300 hours. The transfer films from the lamellar solid MoS2 and metal composite retainers improved the torque and wear properties. For ceramic, i.e., silicon nitride, balls used with steel rings, wear occurred on the inner rings. All ceramic bearings with composite retainers showed improved torque and wear properties. 18 refs.
Crystalline {alpha}-Fe{sub 2}O{sub 3} powder was prepared by the mechanical milling of crystalline {alpha}-FeOOH at room temperature in air. This result means that crystalline {alpha}-FeOOH is dehydrated by mechanical milling at room temperature. The obtained {alpha}-Fe{sub 2}O{sub 3} powder worked as a rechargeable electrode material in lithium ion conductive organic electrolytes. The electrodes exhibited high discharge capacities of over 1000mAhg{sup -1} corresponding to 6 Li per {alpha}-Fe{sub 2}O{sub 3} at potentials ranging from the open circuit potential to 0.5V (versus Li{sup +}/Li) in the first discharging (lithium insertion) process. This suggests that the valence deviation from Fe{sup 3+} in {alpha}-Fe{sub 2}O{sub 3} to Fe{sup 0} may be caused by electrochemical reduction. In contrast, after the first discharge, the electrodes exhibited high charge capacities of more than 700mAhg{sup -1} corresponding to 4.2 Li ...
Liquid metal ion sources (LMISs) with Ga as ion species are widely used in focused ion beam (FIB) technology for micromachining and surface treatment on the sub-micron and nano-scale. Key features of a LMIS for investigating mechanical properties and 3D-microfabrication of materials are long life-time, high brightness, stable ion current and a highly effective milling ability for the material to be modified. In order to increase the material removal rate, heavier ions than Ga and their clusters should be applied. Bismuth (Bi) is the heaviest, non-radio-active element in the periodic table, is non-toxic and exhibits a low melting point. We have thus produced a long-life (about 1000 h) Bi LMIS with a good beam performance, applicable in any FIB system. Since Bi is the only element in this source, it is not necessary to separate it from other ions by a mass filter. Investigation of the sputtering rate of ...
Corrosion is a materials degradation process that engineering personnel in the pulp and paper industry have had to accept as unavoidable to some degree, due to aggressive processing conditions prevalent in paper mills. The increasing incidence of corrosion-related failures in plant and equipment has resulted in the introduction of new techniques to monitor corrosion rates, since many of the more traditional methods do not provide data that is either recent or accurate enough. Thin layer activation (TLA) is a new corrosion monitoring technique which has recently been employed to measure corrosion trends inside a continuous pulp digester. With TLA a surface is irradiated by a particle beam from a nuclear accelerator, causing it to be labelled with an accurate depth profile and low level radioactivity. By monitoring this activity, it is possible to calculate how much of the surface has been removed by corrosion. 14 refs., 7 figs., 4 tabs.
Corrosion is a materials degradation process that engineering personnel in the pulp and paper industry have had to accept as unavoidable to some degree, due to aggressive processing conditions prevalent in paper mills. The increasing incidence of corrosion-related failures in plant and equipment has resulted in the introduction of new techniques to monitor corrosion rates, since many of the more traditional methods do not provide data that is either recent or accurate enough. Thin layer activation (TLA) is a new corrosion monitoring technique which has recently been employed to measure corrosion trends inside a continuous pulp digester. With TLA a surface is irradiated by a particle beam from a nuclear accelerator, causing it to be labelled with an accurate depth profile and low level radioactivity. By monitoring this activity, it is possible to calculate how much of the surface has been removed by corrosion. 14 refs., 7 figs., 4 tabs.
Alumina-reinforced carbon nanofiber nanocomposites were prepared using different routes; powders mixture, colloidal route and sol?gel process followed by spark plasma sintering (SPS). CNFs/xAl2O3 (x = 10?50 vol.%) were prepared through nanopowders mixing in a high-energy attrition milling. The main limitations in the preparation of this kind of nanocomposites are related to the difficulty in obtaining materials with a homogeneous distribution of both phases and the different chemical nature of CNFs and Al2O3, which causes poor interaction between them. A surface coating of CNFs by wet chemical routes with an alumina precursor is proposed as a very effective way to improve the interaction between CNFs and Al2O3. An improvement of 50% in fracture strength was found for similar nanocomposite ...
Statement of problem Computer-aided design/computer-aided manufacturing (CAD/CAM) titanium ceramic restorations were developed with the potential for replacing expensive, high noble metal ceramic restorations. However, there is a lack of information about the clinical performance of CAD/CAM titanium ceramic single crowns. Purpose The purpose of this study was to evaluate CAD/CAM titanium ceramic single crowns after 3 years in function. Material and methods A total of 41 crowns were fabricated for 21 patients. The titanium copings were CAD/CAM milled (Everest CAD/CAM system) with an even thickness of 0.5 mm, and low-fusing veneering porcelain (Vita Titanium Porcelain) was added incrementally. The crowns were cemented using zinc phosphate cement after confirming that there were no mechanical...
The aim of this study was to develop a nanostructured Nb2O5-natural hydroxyapatite bulk composite to serve as an alternative biocompatible bulk material for implants. A set of samples of hydroxyapatite from fish bones with different concentrations of Nb2O5 were designed. They were prepared through a milling process, compacted under different pressures (350, 450, 550 and 650MPa) and sintered in air atmosphere at 1000^oC for 1h. The results revealed that the prepared composites presented strong interactions between the two elements and showed improvement in the sinterability with significant densification and microstructure changes, suggesting that they are promising for implants meant to replace bone tissues.
Focussed ion beam (FIB) processing has been applied to the fabrication of novel InP-based cleaved coupled cavity (CCC) quantum cascade lasers (QCL). Gas assisted etching using XeF{sub 2} has been shown to significantly reduce the redeposition of sputtered material onto the mirror surfaces during final milling. For the unprocessed laser a broad spread of lasing peaks are observed between 9.72{mu}m to 9.78{mu}m at a current of 380mA (1kA/cm{sup -2}). After FIB processing, substantial side mode suppression is observed on applying a current of 20mA (100A/cm{sup -2}) to the short section and the main lasing peak is observed at 9.77{mu}m.
Focussed ion beam (FIB) processing has been applied to the fabrication of novel InP-based cleaved coupled cavity (CCC) quantum cascade lasers (QCL). Gas assisted etching using XeF_2 has been shown to significantly reduce the redeposition of sputtered material onto the mirror surfaces during final milling. For the unprocessed laser a broad spread of lasing peaks are observed between 9.72#mu#m to 9.78#mu#m at a current of 380mA (1kA/cm"-"2). After FIB processing, substantial side mode suppression is observed on applying a current of 20mA (100A/cm"-"2) to the short section and the main lasing peak is observed at 9.77#mu#m.
Statement of problem Titanium is the most biocompatible metal used for dental casting; however, there is concern about its marginal accuracy after porcelain application since this aspect has direct influence on marginal fit. Purpose The purpose of this study was to determine the effect that metal selection and the porcelain firing procedure have on the marginal accuracy of metal ceramic prostheses. Material and methods Cast CP Ti, milled CP Ti, cast Ti-6Al-7Nb, and cast Ni-Cr copings (n=5) were fired with compatible porcelains (Triceram for titanium-based metals and VITA VMK 95 for Ni-Cr alloy). The Ni-Cr alloy fired with its porcelain served as the control. Photographs of metal copings placed on a master die were made. Marginal discrepancy was determined on the photographs using an image ...
Composting of sawdust and paper mill sludge, using a 'Kneer' process reactor, was studied in an attempt to elaborate upon organic matter transformation during the process and to define parameters to measure the compost maturity level. Temperature, electron paramagnetic resonance data, ash and C, H, N and S contents, and a spectroscopic method using ultraviolet-visible (UV-VIS) for alkaline (pH = 8.5) and solid samples was used to study the maturity of the compost samples. These parameters were measured in 6 humic acids extracted from the compost samples during 29 days. The results of this work show that the 'Kneer' process is efficient in transforming ligno-celulitic residues in a short time (29 days), into an organic fertilizer material with application perspectives (author)
In the present work, bulk amorphous and nanocrystalline Al83Fe17 alloys were obtained by consolidation of mechanically alloyed powders. Mechanical alloying of Al-17% Fe powder mixture yielded powder with an amorphous structure. Thermal behaviour of the milling product was examined using differential scanning calorimetry. This investigation revealed that the amorphous phase crystallised above 380^oC. The amorphous powder was compacted under a pressure of 7.7GPa in different conditions: at 380^oC for 600s and at 1000^oC for 180s. Structural investigations of the bulk material revealed that the amorphous structure was retained after consolidation process applied at 380^oC. Compaction under high pressure at 1000^oC caused crystallisation of the amorphous phase and appearance of metastable nano...
Studies of asphalt emulsion sealants conducted by the Pacific Northwest Laboratory have demonstrated that the sealants are effective in containing radon and other potentially hazardous material within uranium tailings. The laboratory and field studies have further demonstrated that radon exhalation from uranium tailings piles can be reduced by greater than 99% to near background levels. Field tests at the tailings pile in Grand Junction, Colorado, confirmed that an 8-cm admix seal containing 22 wt% asphalt could be effectively applied with a cold-mix paver. Other techniques were successfully tested, including a soil stabilizer and a hot, rubberized asphalt seal that was applied with a distributor truck. After the seals were applied and compacted, overburden was applied over the seal to protect the seal from ultraviolet degradation.
Studies of asphalt emulsion sealants have demonstrated that the sealants are effective in containing radon and other potentially hazardous material within uranium tailings. The laboratory and field studies have further demonstrated that radon exhalation from uranium tailings piles can be reduced by greater than 99% to less than background levels. Field tests at the tailings pile in Grand Junction, Colorado confirmed that an 8-cm admix seal containing 22 wt % asphalt could be effectively applied with a cold-mix paver. Other techniques were successfully tested, including a soil stabilizer and a hot, rubberized asphalt seal that was applied with a distributor truck. After the seals were applied and conpacted, overburden was applied over the seal to protect the seal from ultraviolet degradation. 14 figures.
There is an increasing number of applications for hard coatings in engineering where the properties of the single-layer coating are not sufficient. One way to solve this problem is to use a multilayer coating that combines the properties of several coating materials. In this study, TiN-CrAlN and CrN-CrAlN multilayer coatings were deposited on 100Cr6 and S6-5-2 (DIN) steel substrates, by means of unbalanced magnetron sputtering. For comparison, TiN, CrN and CrAlN single-layer coatings were also prepared. For all depositions the coating temperature was below 473 K. Indentation testing, hardness measurements and scratch tests were performed to characterize the mechanical properties. The correlation between the wear behavior in rolling contact and the mechanical properties of the multilayer coatings is reported. A ball crater preparation technique through scratch tests and wear tracks was used to observe the deformation and fracture behavior ...
Ceramic antifriction bearings were introduced in excellent characterics and application. In main shaft use bearings of the machine tool, to be heightened in efficiency and accuracy by the heightening in speed, centrifugal load to the outer ring is not negligible to shorten the bearing in life. Also ball bearings with a contact angle are easily corroded by a very strong revolution slide due to the gyromoment. The use of such light weight material as silicon nitride's can design the lengthening in life. Also the utilization of high rigidity can prevent the inner ring from expanding by centrifugal force and enable the machining to be with a high accuracy. Ceramic rolling element is excellent also in backing resistant property and effective on the oily film cut. With heat resistant property, it maintains hardness even at high temperature. Such excellent characteristics being utilized, the fine ceramic antifriction bearing is used for the ...
Full text: The focused ion beam (FIB) miller is becoming well established as a machine for the structural analysis of materials and for the rapid preparation of transmission electron microscope specimens. It has also been used for some time in the semiconducting materials industry for the analysis, repair and redesign of device materials. However, one emerging technique is the use of the FIB for micromachining. The FIB software can also be used to manufacture and machine components. This process can occur through converting software, typically in the form of bitmaps or TIF files, to proprietary 'stream' files. These files allow, often complex, patterns to be generated and milled into the specimen and thus the generation of micro-electromechanical systems. Frequently, this involves largely two-dimensional patterns and structures, however, more complex patterns and file types can be generated which allow, ...
Materials Scientists need information on the kinetics of the microstructural evolution processes that determine the finished microstructure, and hence the properties, of any material. E.g. recrystallisation, grain growth and phase changes. Such kinetic information requires reliable discrimination of differently oriented crystallites and/or different crystal phases coupled with useful spatial resolution and temporal resolution (i.e. high frame rates). These imaging results must be realised from a hot and changing specimen, in an instrument that is compatible with that hot specimen and with a practical specimen heater. Focused Ion Beams (FIB) offer strong contrast between crystallites and phases, and hence offer the ability to discriminate between these features even while imaging at fast frame rates, however their compatibility with hot specimens was unproven. Here we report results from a novel combination of FIB with an in-situ heating stage, ...
Beach rocks are observed frequently on the tropical and subtropical sandy beaches where they express thin beds dipping seaward at less than 15 degrees. They consist of beach sediments including fossil shells, fragments of corals, diatoms and other biocarbonates, and are well cemented within the inter-tidal zone with calcium carbonate originated in sea water. Therefore, they are not only good indicators which show the past sea level, but also provide good sample material for radiocarbon dating. The locations of beach rocks give us an optimum condition studying a carbon cycle between land and marine environment by analyzing their isotope fractionations. In order to estimate the origin of calcium carbonate which worked as an adhesive when beach rocks were formed and to estimate the formative ages of beach rocks, a total of 330 fossil corals, fossil shells and calcarenite or calcirdite samples were collected from 128 sites of 16 islands consisting of the Nansei ...
Running torque of bearings, temperature rise of the lubricating oil and power loss of the testing system were compared with hybrid ceramic bearings set HIP-Si{sub 3}N{sub 4} balls and AISI-M 50 steel ball bearings under the 2 million dN value ({phi}20 x 100,000 rpm). Over 1.4 dN value, hybrid ceramic bearings showed superior performance than M 50 steel ball bearings. If the proper oil filling condition is chosen, hybrid ceramic bearings reduce bearing power loss to about 55% of AISI-M 50 steel ball bearings at 2 million dN value. (author)
It is suggested that the model of a neutrino ball described in terms of the standard model extended by adding right-handed neutrinos and the Majorana scalar field can be presented in order to explain a body of weak interacting neutrinos. Neutrino interaction with the scalar Majorana field violates the lepton number and produces the mass splitting of neutrino due to the sea-saw mechanism. In this model a neutrino ball is an object which appears as a result of a first order cosmological phase transition. It can be regarded as a ball filled with Dirac neutrinos and can be treated as a remnant of the phase transition with unbroken global lepton symmetry. In this paper we study the macroscopic parameters of such a configuration. In the result the mass-radius curve M(R) for this object is obtained. (orig.).
In this effort, the nonlinear responses and stability of a spindle system supported by ball bearings are presented. The dynamics of this system is described by a set of second order differential equations with a nonlinear piecewise smooth force. The Floquet theory is applied to investigate the stability of the periodic solution. Due to the loss of contact between the raceways and balls in the ball bearing, the bending of the frequency response curves switch to the left at the weak resonance region, which is similar to the frequency response curves of a system with a soft spring. With the decrease of the bearing clearance, the bending of the frequency response curves switch to the right, which is similar to the frequency response curves of a system with a hard spring. Increase of the frequency ratio, the bending of frequency response curves transforms from left to right. The route to chaos through a period doubling process ...
The lignite used for Phase I of the project was a Texas lignite from the Martin Lake mine obtained from the stockpile for the Martin Lake Power Plant of the Texas Utilities Generating Company. The power requirements for the fluid-energy mill were determined from the measured steam (or air) temperatures, pressures and pressure drops and the lignite flow rate. The instrument locations for the tests are shown on Figure 1. All of the instruments were connected to a microcomputer via an analog input interface board. Data were recorded on disks periodically throughout the tests. Appropriate calibration procedures were followed to assure that reliable data were being obtained. The combined grinding/drying tests were conducted in Vicksbuth, MS at Ergon, Inc.'s fluid-energy-mill facility. both steam and air were used as grinding fluids. With steam, tests were used as grinding fluids. With steam, tests were run with the following temperatures ...
The forest products industry is the third largest economic sector in Alberta, producing pulp and paper, dimensional lumber, paneling, and value added products, providing some 40,000 jobs . 'Value added' is a key component of expanding economic activity within the forest products sector. Wood residues can play a key role in obtaining more value from forest resources by providing new products, serving as feedstock to energy and chemical production, and playing a role in agriculture and land reclamation. One of the principal roles of the Forest Products Development Branch of the Alberta Economics Department is to encourage the development of the industry by creating new uses for these materials and developing awareness of the scope of the resource. Distances to markets, economic competition from conventional energy sources and coordination of research efforts are substantial barriers to further development that the Forest Products Development Branch ...
Si/Ni alloy and graphite composites were synthesized using arc-melting followed by high energy mechanical milling (HEMM). Alloy particles comprising of NiSi2, NiSi and Si phases were distributed finely and uniformly on the surface of graphite in the composites obtained after Hem. The composite containing 60 wt.% of Si/Ni alloy exhibited a stable capacity of ?780 mAh/g. Fourier transform infrared spectroscopy (FTIR) analysis confirmed that some bonds were formed between alloy and graphite after HEMM, which appeared to retain the electrical connection between alloy and graphite during cycling. X-ray diffraction (XRD) analysis indicated that NiSi2 and NiSi phases, which acted as an inactive alloy matrix remained invariant during charge and discharge. In addition to NiSi2 and NiSi phases, disordered graphite layers also played the role of media for the accommodation of large volume change of Si during cycling. The large reversible capacity and good cycleability showed ...
This report presents geologic considerations that are pertinent to the Remedial Action Plan for Slick Rock mill tailings. Topics covered include regional geology, site geology, geologic stability, and geologic suitability.
The authors derive in full details the Hamiltonian formulation of the N = 1D = 10 supergravity coupled to super Yang-Mills theory. In particular, they present the explicit form of the first class constraints and compute the constraints gauge algebra.
Bacillus thuringiensis was isolated from 36 of 50 residue samples obtained from an animal feed mill (a stored-product environment). Of 710 selected colonies having Bacillus...Full Text Available
A comparative study has been carried out of the growth of two lines of Datura innoxia (Mill.) cells, designated DI-6 and NR1, their resistance to chlorate, and their ability to assimilate...Full Text Available
Noncommutative tori are among historically the oldest and by now the most developed examples of noncommutative spaces. Noncommutative Yang-Mills theory can be obtained from string theory. This connection led to a cross-fertilization of research in physics and mathematics on Yang-Mills theory on noncommutative tori. One important result stemming from that work is the link between T-duality in string theory and Morita equivalence of associative algebras. In this article we give an overview of the basic results in differential geometry of noncommutative tori. Yang-Mills theory on noncommutative tori, the duality induced by Morita equivalence and its link with the T-duality are discussed. Noncommutative Nahm transform for instantons is introduced.
Squeeze film dampers (SFD) are devices utilized to control vibrations of the shafts of high-speed rotating machinery. The SFD - squirrel cage combination is probably the most used system for tuning the stiffness and damping of the supports for rotors installed on ball bearings. Squeeze film dampers are essentially hydrodynamic bearings which contain the ball bearings housings of ball-bearings supported shafts. Consequently, the oil film within the SFD are influenced only by the precession and nutation of the shaft, that is the flow of the oil within the damper is not directly influenced by the spin of the rotor. However, in the classical theory, the flow in the thin film is also governed by the Reynolds equation. In this paper, some of the limits of the classical theory of the SFD are discussed and theoretical and experimental studies, which illustrate the ideas presented herein, are presented as well. The orbits of an ...
Ball screw bearings are used for the fine control of Control Rod Drive Mechanism (CEDM) for the SMART-P. Because the friction coefficient of the ball screw bearings suddenly increases at the limit temperature of 120 .deg. C, the surrounding temperature of the ball screw bearings should be less than the limit temperature for the functional integrity of the CEDM. The CEDM coolers are installed at the lower portion of the ball screw bearings to maintain the bearings' temperature less than the limit. In order to check the CEDM cooler satisfy the temperature limit of ball screw bearing at the possible operational conditions, the cooling capacity of the CEDM coolers, which was determined at the stage of 'conceptual design', is evaluated using the Computational Fluid Dynamics(CFD) code, Fluent. The analysis result shows that the current CEDM coolers satisfy the ...
Ball screw bearings are used for the fine control of Control Rod Drive Mechanism (CEDM) for the SMART-P. Because the friction coefficient of the ball screw bearings suddenly increases at the limit temperature of 120 .deg. C, the surrounding temperature of the ball screw bearings should be less than the limit temperature for the functional integrity of the CEDM. The CEDM coolers are installed at the lower portion of the ball screw bearings to maintain the bearings' temperature less than the limit. In order to check the CEDM cooler satisfy the temperature limit of ball screw bearing at the possible operational conditions, the cooling capacity of the CEDM coolers, which was determined at the stage of 'conceptual design', is evaluated using the Computational Fluid Dynamics(CFD) code, Fluent. The analysis result shows that the current CEDM coolers satisfy the CEDM temperature limit of ...
This paper reviews the mill flowsheet applied at the SOMAIR (Societe des Mines de l'Air) uranium mill in Niger. It focuses on the yellow cake quality improvements achieved by molybdenum and zirconium elimination through double yellow cake precipitation in tanks at first stage and through size/density control in a fluidized bed precipitator at second stage. Water saving aspects in the plant are also presented. (author)
This paper reviews the mill flowsheet applied at the COMINAK uranium mill (Compagnie Miniere d'Akouta) in Niger. For ore treatment, it focuses on the major improvements to the operations using sulfonitric pugging and solids/liquid separation using belt filter double filtration after leaching. The precipitation circuits have been improved with molybdenum elimination through caustic washing of the yellow cake. (author)
Scour around offshore structures is well known. It is caused by the strong eddy formation at the base of the structures protruding from the sea bottom. The strong vortices result in an amplified effective shear stress working on the sea bottom surface adjacent to the structure. When the surrounding sea bottom is lowered the scour protection will end up being a cap on a small hill and when the slopes are getting too steep the scour protection will roll or slide down the sides. It will loose its cohesion and therefore its integrity. This will take place irrespective of the type of scour protection material and the type of scour protection. This report describes scour protections, which can deal with this particular problem. Such a scour protection must be able to sustain the following loads: Be able to follow the lowering of the seabed on its way down; Be resistant to edge scour (scour around the perimeter of the scour protection). The installation of scour ...
20 nm thick permalloy elements, with dimensions of 500 x 500 nm"2 and 1000 x 200 nm"2, have been fabricated on 50 nm thick silicon nitride substrate by milling using a focussed ion beam (FIB) microscope. The dose of ion beam used for the milling was varied in order to achieve the best definition for the milled areas. The FIB milled elements were characterised physically by atomic force microscopy (AFM) and bright field transmission electron microscopy (TEM) and magnetically by Fresnel imaging on a TEM modified for magnetic imaging. The FIB milled elements were found to have a more irregular edge and lower magnetic fields for events such as vortex annihilation when compared to elements of the same dimensions fabricated by conventional electron beam microscopy (EBL).
Naturally occurring radionuclides are present in most material. The most common naturally occurring radionuclides in material are those of the uranium and thorium series and potassium-40. This material is commonly referred to as Naturally Occurring Radioactive Material (NORM). In some material the levels of naturally occurring radionuclides are significantly higher, to the extent that regulatory control may be required for radiation protection purposes. Regulation of NORM presents a range of new challenges for both regulators and operators. Unlike more traditional industries dealing with radionuclides, NORM industries have generally not had any radiological oversight and, for example, are not equipped for radiological monitoring. Some consumer goods containing NORM, which have not traditionally been considered as a radiological problem (such as some fertilizers), may require ...
The sensitivity analysis summarized in this paper was made to determine the parameters of greatest influence in the prediction of radon barrier cover thickness for the stabilization of uranium mill tailings piles. Such information provides the basis for setting priorities and levels of effort for data collection, and improves knowledge of the sources of uncertainty in the calculation of cover thickness. In the context of this paper, the influence of a parameter on cover thickness incorporates two effects: (1) the sensitivity of the mathematical formulation to changes in a parameter's value, and (2) the range of values that a parameter may take on under site-specific conditions. Of the several parameters that are used in the calculations, the most influential are cover moisture content, cover radon diffusion coefficient, tailings radium concentration and tailings radon emanating fraction, in order of decreasing relative influence. Less influential parameters for ...
This paper presents a summary of the first phase of the EPA project, which encompasses surveys of residues from industrial sources in Alexandria. Studies to date indicate that wastes from various industries can be recovered economically. Wastes such as tin cans, glass, wastepaper, and food residues from processing of fruits, starch, and beer are examples of reusable industrial wastes in Egypt. The results of experimental studies for reuse of residues from oil refining, starch and yeast processing, and steel pickling are presented. Spent clay from edible oil refining is currently discarded, causing both handling and disposal problems. This clay contains as much as 40% oil; 90% can be recovered by extraction. The recovered oil can be successfully used in soap production, and the spent clay can be reused in oil bleaching. Other examples include starch and yeast wastes, which can be used for animal feed, and spent pickling liquor, which can be used as a coagulant aid for treating paper ...
In an effort to develop cost-efficient techniques for remediating uranium contaminated groundwater at DOE Uranium Mill Tailing Remedial Action (UMTRA) sites nationwide, Sandia National Laboratories (SNL) deployed a pilot scale research project at an UMTRA site in Durango, CO. Implementation included design, construction, and subsequent monitoring of an in situ passive reactive barrier to remove Uranium from the tailings pile effluent. A reactive subsurface barrier is produced by emplacing a reactant material (in this experiment various forms of metallic iron) in the flow path of the contaminated groundwater. Conceptually the iron media reduces and/or adsorbs uranium in situ to acceptable regulatory levels. In addition, other metals such as Se, Mo, and As have been removed by the reductive/adsorptive process. The primary objective of the experiment was to eliminate the need for surface treatment of tailing pile effluent. Experimental design, and ...
Rehabilitation of open-cut coal mining spoils at Collie, Western Australia, requires amelioration before adequate survival and growth of rehabilitation species can occur. Lolium ridgidum was used in a greenhouse pot experiment to assess the ability of lime (CaCO/sub 3/) and two waste-products of regional industry, bauxite processing caustic waste (red mud) and timber milling refuse (sawdust), to render the low pH spoils suitable for plant growth. CaCO/sub 3/ at 1% and red mud at 18% were both effective in reducing acidity and levels of available Al in the overburden. Red-mud treatment produced 10-fold increases in plant dry matter accumulation over the CaCO/sub 3/ treatment when no fertilizer was used. This is due to the presence of significant amounts of phosphorus in the red mud. With additions of a balanced NPK fertilizer at 0.077%, CaCO/sub 3/ treatment produced the best plant growth in this overburden. The re-use of the red-mud wastes for amelioration, ...
The forced nonlinear vibration and its stability of a single-degree-of-freedom system with a ball screw type damper which is composed of a ball screw, a flywheel and a flyball governor are discussed theoretically. The results are compared with a linear solution and the experimental results. The effect of vibration isolation of the damper is also discussed. Numerical examples are given for several ratios of the natural frequencies in the primary system to the governor. It is demonstrated that, when the natural frequency ratio is chosen suitably, the damper is effective in suppressing the resonance of the primary system. The amplitude response curve of the primary system is approximately equal to the linear solution except in the vicinities of the natural frequencies of the primary system and the governor, and is stable except in the vicinity of the natural frequency of the governor. (author).
The effects of vibration isolation of the new type of mechanical damper applied to a single-degree-of-freedom system and a simple beam are discussed numerically and experimentally. The damper is composed of a ball screw, a flywheel and centrifugal brakes, and possesses nonlinear characteristics. The Continuous System Simulation Language is used for the digital simulations of the nonlinear vibration systems. The results may be summarized as follows: (1) The damper is effective for suppressing the amplitude of the single-degree-of-freedom system as well as of the beam at the point of attachment of the damper, at the resonances. (2) The damper approaches a snubber for smaller values of lead L of the ball screw (or larger values of moment of inertia J of the flywheel), and acts like a damper whose damping force is proportional to the square of the velocity for larger values of L (or smaller values of J). (author).
Ceramic ball bearings of silicon nitride are used for hard disk drive (HDD) spindle motors, to increase seed, reliability and memory capacity of the HDDs. Silicon nitride ceramics have advantages of lightweight, high strength and hardness over the conventional steel for bearings, but is expensive. A new process of high cost performance has been developed for mass production of the small-size ceramic balls. The company plans to apply these bearings to higher devices, e.g., servers, for the time being, and to expand the applicable areas, e.g., common devices and other small-size motors. The ceramic bearings have been developed jointly with Koyo Seiko Co. Ltd. (translated by NEDO)
Full text: In Hungary, the main goal is that the Hungarian regulations should meet with the EU Directive No. 96/29. For this aim, a surveying project has been launched in order to collect all relevant information about the Hungarian TENORM situation. This surveying programme covers a lot of data collection (work activities, disposal places, residue quantities) and radiological measurements on the TENORM site. The Hungarian situation of TENORM definitely differs from other countries in the aspect of occurrence forms of natural sources (or in the imported raw materials), in the quantities of exploitation, in the level of the radioactivity and in the applied technological processes. Firstly, those work activities have been choosen where the huge amount of residues have been produced. The other criteria is that the activity concentration in a great portion of the given residues is much higher than the average activity concentration of the typical Hungarian soil. After ...
As part of a study into the properties of ferroelectric single crystals at nanoscale dimensions, the effects that focused ion beam (FIB) processing can have, in terms of structural damage and ion implantation, on perovskite oxide materials has been examined, and a post-processing procedure developed to remove such effects. Single crystal material of the perovskite ferroelectric barium titanate (BaTiO_3) has been patterned into thin film lamellae structures using a FIB microscope. Previous work had shown that FIB patterning induced gallium impregnation and associated creation of amorphous layers in a surface region of the single crystal material some 20 nm thick, but that both recrystallization and expulsion of gallium could be achieved through thermal annealing in air. Here we confirm this observation, but find that thermally induced gallium expulsion is associated with the formation of gallium-rich platelets on the surface ...
We report the direct molecular dynamics simulations for molecular ball bearings composed of fullerene molecules (C{sub 60} and C{sub 20}) and multi-walled carbon nanotubes. The comparison of friction levels indicates that fullerene ball bearings have extremely low friction (with minimal frictional forces of 5.283 x 10{sup -7} and 6.768 x 10{sup -7} nN/atom for C{sub 60} and C{sub 20} bearings) and energy dissipation (lowest dissipation per cycle of 0.013 and 0.016 meV/atom for C{sub 60} and C{sub 20} bearings). A single fullerene inside the ball bearings exhibits various motion statuses of mixed translation and rotation. The influences of the shaft's distortion on the long-ranged potential energy and normal force are discussed. The phonic dissipation mechanism leads to a non-monotonic function between the friction and the load rate for the molecular bearings.
IMO Momentenlager GmbH of Gremsdorf near Nuremberg produces large rotary bearings for ENERCON wind power systems, preferably for the E-70 and E-82 generators. (orig.)
The thermal contact resistance between balls and inner and outer rings of thermally steady space-use deep groove ball bearings was studied experimentally to verify the validity of the previously proposed calculation method for the resistance. The 440C stainless steel single row bearing was used for measuring its steady state temperature distributions in a vacuum environment under axial, radial and combined load conditions. As a result, the experimental results of the resistance well agreed with calculated ones under each load condition resulting in the sufficient validity at nearly the same surface roughness. It was necessary to apply a static equivalent radial load to calculation under the combined load that a contact angle is larger than the angle of resultant force dependent on both load components. In experiments under only radial load, measurement of outer ring temperatures was necessary at some points with no contact with ...
Seven high-school trainees each conducted training sessions with two profoundly retarded children. Each trainee was asked to teach one child to follow the instruction "Bring ball" and the other child...Full Text Available
Plasma nitriding is usually used for ferrous materials to improve their surface properties. Knowledge of the properties of thin surface layers is essential for designing engineering components with optimal wear performance. In our study, we investigated the microstructural, mechanical and tribological properties of plasma- and pulse plasma-nitrided AISI 4140 steel in comparison to hardened steel. The influence of nitriding case depth as well as the presence of a compound layer on its tribological behaviour was also examined. Plasma and pulse plasma nitriding were carried out using commercial nitriding processes. Nitrided samples were fully characterised, using metallographic, SEM microscopic, microhardness and profilometric techniques, before and after wear testing. Wear tests were performed on a pin-on-disc wear testing machine in which nitrided pins were mated to hardened ball bearing steel discs. The wear tests were carried out under dry ...
The world`s population of research reactors is growing old. Many have been adapted to serve new purposes over their lives, from testing materials for nuclear power programmes and supporting neutron physics experiments, to colouring gemstones, doping silicon and generating medical isotopes. In the first article of this survey of research reactor issues, Wilfried Krull from GKSS in Germany describes the effects on a reactor of supporting these changes in application as ``design ageing`` . Managing this and other symptoms of ageing to extend plant life is a key task for operators, and Krull discusses the efforts being made internationally to handle them. Eventually, terminal decline of one vital component can determine when a reactor has to be shutdown for refurbishment. For BR2 in Belgium, it was the beryllium matrix. Edgar Koonen from SCK-CEN explains work being done to replace it and extend reactor life for around 15 years. The Triga at the University of Austria`s ...
The title invention aims at a vibrations-free running of the flywheel to realize a high speed (18,000-20,000 revolutions per minute). The flywheel consists of a case which holds a central stator, a rotor and two ball-bearings. The ball-bearings have a first radial stiffness and are placed in between the rotor and an upper, respectively lower support bearer. The support bearers are supported on the stator with a second radial stiffness. The top and the bottom of the stator is connected to the case by means of a support with a third stiffness. 6 figs.
With the deposition of PVD hard coatings on the tools applied in machining operations it is possible to achieve significant improvements in the performance and quality of the machining processes. Depending on the machined material and the operating principle, e.g. turning, milling or drilling, not only different machining parameters but also different coating materials are necessary. In interrupted cut machining of tempered steel, for example, the life time of Ti-C-N coated inserts is several times greater than the Ti-C-N coated ones. This is a result of the favourable thermophysical and tribological properties of Ti-N-C. The potential for tool protection by CrN coatings is a result of the high ductility and low internal stress of this coating materials. CrN films can be deposited with greater film thickness, still maintaining very good adhesion. This paper presents the development of new arc PVD ...
Wider coal lines and larger power plant units necessitate measures for increasing the capacity of the mills without driving up power consumption and installation costs. The result of this development is the modern ALSTOM bowl mill. This paper indicates the stages of development which were necessary for this and the experience which could be accumulated through these measures. The paper also describes in detail the areas of flow in the mills, of design of milling equipment, of mill power supply and of grading in this development. (orig.) [Deutsch] Breitere Kohlebaender und groessere Kraftwerkseinheiten zwingen zu Massnahmen, um die Leistung der Muehlen zu vergroessern, ohne jedoch den Kraftbedarf und die Installationskosten in die Hoehe zu treiben. Das Ergebnis dieser Entwicklung ist die moderne ALSTOM-Schuesselmuehle. Der Beitrag zeigt, welche Entwicklungsschritte hierzu ...
Finland has some 10 million hectares of peatland, accounting for almost a third of its total area. Macroclimatic conditions have varied in the course of the Holocene growth and development of this peatland, and with them the habitats of the peat-forming plants. Temperatures and moisture conditions have played a significant role in determining the dominant species of mire plants growing there at any particular time, the resulting mire types and the accumulation and deposition of plant remains to form the peat. While in a natural state the mires of Finland have functioned as carbon dioxide sinks throughout the post-glacial period, but the ditching of peatland for forestry and agriculture, amounting to some 5,7 million hectares in Finland, has affected their water balance, especially over the last hundred years, and has thereby altered the quantity and species composition of the mire vegetation. The invasion of trees and woody plants to replace the typical mire plants following ditching ...
We show that in the Landau gauge of the SU(2) Yang-Mills theory the residual global symmetry supports existence of the topological vortices which resemble disclination defects in the nematic liquid crystals and the Alice (half-quantum) vortices in the superfluid heluim 3 in the A-phase. The theory also possesses half-integer and integer charged monopoles which are analogous to the point-like defects in the nematic crystal and in the liquid helium. We argue that the deconfinement phase transition in the Yang-Mills theory in the Landau gauge is associated with the proliferation of these vortices and/or monopoles. The disorder caused by these defects is suggested to be responsible for the confinement of quarks in the low-temperature phase.
White beam Laue micro-diffraction was performed on directionally solidified, single-crystal Mo pillars in the as-grown state, after focused ion beam (FIB) milling and after pre-straining. The Laue diffraction peaks from the as-grown pillars are very sharp and show no broadening, similar to those from single-crystal Si wafers. Significant broadening and streaking of the peaks occurred after FIB milling and pre-straining, indicative of the damage these treatments induce in the nearly perfect crystal structure of the directionally solidified Mo pillars.
Olive mill effluent (OMW) is an example of a wastewaters containing high concentrations of recalcitrant and toxic compounds which are polyphenolics of different molecular weight. It causes disposal problems because they contain powerful pollutants. Treatment and detoxification of phenolic fraction extracted from olive mill wastewaters as well as a synthetic phenolic mixture was investigated by electro-Fenton method. Results shows that this method is highly efficient in polymerising low molecular mass phenolics and removing a large amount of recalcitrant polyphenolic compounds. This treatment decreased 78% of the toxicity which sustained a good anaerobic post-treatment. (orig.)
... shrouded in secrecy in 2008, Iraq sold its stock of 550 metric tons (in 3,500 barrels) of apparently commercial-grade yellow cake (milled uranium ...
A 206-size hybrid (ceramic/steel) cylindrical roller bearing was tested in MIL-L-23699 C oil at several speeds and loads. Heat-generation data was collected and subsequently correlated with bearing-analysis software. Bearing-cage slip data was also collected at various oil-flow rates, oil temperatures, and with both MIL-L-7808 J and MIL-L-23699 C oils. The hybrid bearing was tested in MIL-L-23699 C oil for for 25 hours at 2220 N radial load and 1.08 MDN shaft speed. The hybrid bearing technology demonstrated in the report is applicable to the Integrated High Performance Turbine Engine Technology Initiative. 15 refs.
The fabrication and characterization of tungsten nanoelectrodes insulated with cathodic electrophoretic paint is described together with their application within the field of neurophysiology....Full Text Available
Off-axis electron holography is used to characterize a linear array of transistors, which was prepared for examination in cross-sectional geometry in the transmission electron microscope (TEM) using focused ion beam (FIB) milling from the substrate side of the semiconductor device. The measured electrostatic potential is compared with results obtained from TEM specimens prepared using the more conventional 'trench' FIB geometry. The use of carbon coating to remove specimen charging effects, which result in electrostatic fringing fields outside 'trench' specimens, is demonstrated. Such fringing fields are not observed after milling from the substrate side of the device. Analysis of the measured holographic phase images suggests that the electrically inactive layer on the surface of each FIB-milled specimen typically has a thickness of 100 nm.
This report documents the technical development for a patent disclosure of a double-clad process for the continuous casting of thin-strip carbon steel. The fundamental idea of the disclosure is to form a product strip by depositing molten steel between two, cooled, clad strips of the same material. The claimed benefits include: (a) the conservation of energy in steel making through the elimination of soaking pits and reheat cycles, and (b) an improved surface on both sides of the as-cast product such that it will be suitable for direct feed to a cold-reduction mill. However, the process as conceived is not necessarily limited to the casting of carbon steel, but may be also applied to other metals and alloys. The work is described under three headings as follows. Preliminary Considerations and Scoping Analysis presents the basic idea of the double-clad, thin-strip casting process; the energy conservation potential; scoping heat transfer ...
The Stardust sample return capsule will return to Earth in January 2006 with primitive debris collected from Comet 81P/Wild-2 during the fly-by encounter in 2004. In addition to the cometary particles embedded in low-density silica aerogel, there will be microcraters preserved in the Al foils (1100 series; 100 {micro}m thick) that are wrapped around the sample tray assembly. Soda lime spheres ({approx}49 {micro}m in diameter) have been accelerated with a Light Gas Gun into flight-grade Al foils at 6.35 km s{sup -1} to simulate the capture of cometary debris. The experimental craters have been analyzed using scanning electron microscopy (SEM) and x-ray energy dispersive spectroscopy (EDX) to locate and characterize remnants of the projectile material remaining within the craters. In addition, ion beam induced secondary electron imaging has proven particularly useful in identifying areas within the craters that contain residue material. Finally, ...
The generation of thermal energy is the great importance for the agribusiness of dairy industry to conservation the quality of milk, taking into account that the electricity is the main source currently used for the thermal energy input. The small agribusiness dairy industry currently practiced in Brazil faces several problems related to the cost of electricity and the distance of rural properties of networks of power. In the current scenario of Brazilian dairy production, there is need for the generation of cold for the milk cooling, and also the heat for the production of hot water around 50 deg C to 60 deg C and also for cleaning of equipment used for milk production and processing. The main objective of this study is the modeling and simulation of integrated recovery process of solid waste, effluents and bioconversion. The specific project objectives are: comparison study of options and technological routes of low cost material for power generation using ...
A description is given of the principal steps involved in `USIMINAS` work roll manufacturing project for its tandem cold mill. The service performance of these rolls was found to be similar to that rolls supplied by traditional manufacturers. (author). 5 refs., 5 figs., 3 tabs.
A new classically stable model of spontaneous compactification is investigated. D=10 dimensional Einstein-Yang-Mills SU(3) x U(1) theory compactifies to CP(3) giving SU(4) x U(1) effective D=4 theory with no tachyons. An effective SU(4) coupling constant is calculated.
In vitro rooting response and indole-3-acetic acid (IAA) levels were examined in two genetically related dwarfing apple (Malus pumila Mill) rootstocks. M.26 and M.9...Full Text Available
Olive oil mill wastewaters (OMW) cause disposal problems because they contain powerful pollutants such as phenolic compounds. Complete biodegradation or removal of these compounds is hardly achieved by a single treatment method. In this work, we investigated 2 integrated technologies for the treatment of the recalcitrant contaminants of OMW, allowing water recovery and reuse for agricultural purposes. (Author)
[1′-14C, 13C6]Indole-3-acetic acid was infiltrated into immature pericarp discs from fruits of tomato (Lycopersicon esculentum Mill., cv Moneymaker)....Full Text Available
... In order to produce organic livestock feed, feed mills must be inspected and certified. If they produce both organic and non-organic feed, they must implement procedures, backed up by records, to prevent the commingling of organic and non-organic feed. This includes steps to clean storage bins and mixing and bagging equipment prior to producing batches of organic feed. Organic feed mills also must prevent ...
The gauge-invariant correlation function for the Yang-Mills field strengths is shown to admit a symmetric decomposition into electric and magnetic components. The spectral weights are seen to obey a sum rule of the superconvergence type, owing to asymptotic freedom. The close relation between the dielectric function, electric-magnetic duality, and the algebra of generalized Chern-Simons charges is illustrated for the linearized Yang-Mills-Higgs system.
Loss of organic matter is one of the main forms of soil degradation in Mediterranean agricultural soils, and external sources of organic matter are required to improve soil properties. the two-phase centrifugation system in the olive-oil extraction industry produces a large amount of olive mill waste sludge (TPOMW) which can be used to add organic C to degraded soils. (Author)
We study the high energy behaviour of Yang-Mills theory under the inclusion of gravity. In the weak-gravity limit, the running gauge coupling receives no contribution from the gravitational sector, if all symmetries are preserved. This holds true with and without cosmological constant. We also show that asymptotic freedom persists in general field-theory-based gravity scenarios including gravitational shielding as well as asymptotically safe gravity.
Contents: expansion of pc mill application to plate mill and tandem cold mill; application of cluster type rolling mill (cr mill) for rolling of special steel (illustration); development of on-line roll grinding system with profile meter; development of new type jet pickling; new technology in continuous annealing furnace (illustration); anti-seismic testing system by 3-dimensional shaking table; development of mitsubishi hybrid desulfurization system; field performance of 500 mw advanced coal fired supercritical pressure operation boiler for unit no. 1 of tsuruga thermal power station, hokuriku electric power co., inc.; development of electronically controlled cylinder liner lubrication system for marine diesel engines; prediction technology on steady-state and transient performance of multi-air conditioners; a knowledge-based system approach to the autonomous piloting and ...
This thesis consists of three parts. In the first part we review the quantization of Yang-Mills theories and perturbative quantum gravity in curved spacetime. In the second part we calculate the Feynman propagators of the Faddeev-Popov ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge. In the third part we investigate the physical equivalence of covariant Wightman graviton two-point function with the physical graviton two-point function. The Feynman propagators of the Faddeev-Popov ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge are infrared (IR) divergent in de Sitter spacetime. We point out, that if we regularize these divergences by introducing a finite mass and take the zero mass limit at the end, then the modes responsible for these divergences will not contribute to loop diagrams in computations of time-ordered products in either ...
A $200 million paper mill being built in Hagerstown, Md., is expected to produce 150,000 bone-dry short tons per year of de-inked, market-grade pulp for writing and printing paper. The 1st Urban Fibers facility, the largest capital project in Hagerstown's history, is slated for completion in the spring. Landegger Recycled Fiber Corp. will operate and maintain the 200,000-square-foot recycling mill and 60,000-square-foot water reclamation plant. The wastepaper recycling mill plans to minimize waste and pollution by: reclaiming 635 tons per day of 100 percent post-consumer mixed office waste from the solid waste stream; saving more than 16 million cubic feet of landfill area per year; conserving the fiber equivalent of 6,700 trees per day; using no chlorine; saving about 2,000 gallons of water and 4,000 kilowatt hours of electricity per ton of throughput, compared to virgin fiber mills; reusing ...
Described herein are the latest trends in rolling mill facilities toward the 21st. century and new techniques developed by Hitachi Ltd. These cover hot rolling facilities, such as two-stage twin, high crown control-roll cross mill, roll shaping machine and continuous hot rolling systems; cold rolling facilities, such as pickling line-tandem cold mill and other continuous systems; and fine steel rolling facilities, such as roll mill for very small diameter pipes and others to improve productivity and product quality. The other new techniques include systems to pursue reliability and maintainability, in which electric appliances, instruments and computers are integrated, or equipped with built-in large-capacity inverters and drivers. For hot rolling, the above techniques lead to development of a new system named Hi-HOT, which produces high-quality hot coils at a sufficient speed, while keeping rolled ...
This paper explains technologies for turbo chargers used in light cars. Light car engine turbo chargers have been given various improvements responding to needs of the market. Since ball bearings have less mechanical loss than sliding bearings, and enhances greatly the turbo efficiency, they are used in some high performance engines of light cars. While the conventional ball bearing has used high hardness bearing steel, the new standard cars started using ceramic ball. The currently used light car gasoline engines are divided into two kinds, serial three-cylinder type and serial four-cylinder type, either having merits and demerits. The new twin entry turbo developed by IHI arranges divided exhaust gas ports above and below to simplify the manifold shape, and realizes smooth flow by twisting the exhaust gas flow path inside the turbine housing. This makes the dynamic pressure of the exhaust gas more effectively utilized, ...
A 308-size hybrid ball bearing, with ceramic balls and steel rings, was tested using a diester oil and gas turbine fuel as lubricants at several speeds and loads. Heat generation data from this test work was then correlated with the heat generation model from a widely used computer code. The ability of this hybrid split inner ring bearing design to endure thrust reversals, which are expected in many turbine applications, was demonstrated. Finally, the bearing was successfully endurance tested in JP-10 fuel for 25 hours at 7560 N axial load and 36,000 rpm. This work has successfully demonstrated the technology necessary to use fuel-lubricated hybrid bearings in limited-life gas turbine engine applications such as missiles, drones, and other unmanned air vehicles (UAVs). In addition, it has provided guidance for use in designing such bearing systems. As a result, the benefits of removing the conventional oil lubricant system, i.e., design ...
A parametric experimental investigation of an 85 millimeter bore angular contact ball bearing running in RP-1 fuel was performed at speeds of 10,000 to 24,000 rpm. Thrust loads were varied from 4450 to 17,800 Newtons (1000 to 4000 lbs.). Radial loads were varied from 1335 to 13,350 Newtons (300 to 3000 lbs.). RP-1 lubrication for the bearing was provided through a stationary jet ring located adjacent to the test bearing outer ring. Increases in both the thrust and radial loads resulted in increased bearing temperature, while increases in shaft speed resulted in much more dramatic increases in bearing temperature. These trends are typical for ball bearings operating under these types of conditions. Results are given for outer ring temperatures of the test bearing at the various test conditions employed. In addition, the heat energy removed from the bearing by the RP-1 was determined by measuring the increase in temperature as the RP-1 passed ...
Extensive experimental investigation has been carried out on used flight bearings of the high pressure oxidizer turbopumps (HPOTP) of the space shuttle main engine (SSME) in order to determine the dominant wear modes, their extent, and causes. The paper presents the methodology, various surface analysis techniques used, results, and discussion. The mode largely responsible for premature bearing wear has been identified as adhesive/shear peeling of the upper layers of bearing balls and rings. This mode relies upon the mechanisms of scale formation, breakdown, and removal, all of which are greatly enhanced by the heavy oxidation environment of the HPOTP. Major causes of the high wear rates appear to be lubrication and cooling, both inadequate for the imposed conditions of operation. Numerous illustrations and evidence are provided. 22 refs.
Drosophila melanogaster is a model organism rich in genetic tools to manipulate and identify neural circuits involved in specific behaviors. Here we present a technique for two-photon calcium imaging in the central brain of head-fixed Drosophila walking on an air-supported ball. The ball's motion is tracked at high resolution and can be treated as a proxy for the fly's own movements. We used the genetically encoded calcium sensor, GCaMP3.0, to record from important elements of the motion-processing pathway, the horizontal-system lobula plate tangential cells (LPTCs) in the fly optic lobe. We presented motion stimuli to the tethered fly and found that calcium transients in horizontal-system neurons correlated with robust optomotor behavior during walking. Our technique allows both behavior ...
The scope of the present article is two-fold. Firstly, to conduct an experiment to provide the temperature-time history of the cooling of a hot ball bearing in quiescent ambient air. Secondly, to predict the temporal variation of the bearing under the hypothesis of natural convection, radiation or natural convection coexists with radiation for a non-vanishing total hemispherical emissivity of the surface of the bearing. Numerical solutions of the three governing nonlinear lumped heat equations were carried out with a Runge-Kutta-Fehlberg (RKF45) algorithm accounting for automatic step size control. The experimental data was obtained with chrome steel ball bearings of diameter 0.953 cm (7/16 in) heated in an electric oven to a pre-set temperature. The heated bearing was exposed later to ambient air at atmospheric temperature and pressure. (orig.)
Consider the set of source distributions within a fixed maximum relative entropy with respect to a given nominal distribution. Lossless source coding over this relative entropy ball can be approached in more than one way. A problem previously considered is finding a minimax average length source code. The minimizing players are the codeword lengths --- real numbers for arithmetic codes, integers for prefix codes --- while the maximizing players are the uncertain source distributions. Another traditional minimizing objective is the first one considered here, maximum (average) redundancy. This problem reduces to an extension of an exponential Huffman objective treated in the literature but heretofore without direct practical application. In addition to these, this paper examines the related problem of maximal minimax pointwise redundancy and the problem considered by Gawrychowski and Gagie, which, for a sufficiently small relative entropy ball, ...
The use of the focused ion beam (FIB) systems has increased to a high level in recent years. The imaging, milling, and deposition capabilities of the FIB make it the ideal instrument for e.g., site-specific failure analysis, specimen preparation and nano-machining. Ion channelling contrast allows for selective imaging of polycrystalline and polyphase microstructures. In addition, the FIB and CrossBeam registered instruments are unique stand-alone analytical tools. Their vast capabilities have enabled numerous applications into the semiconductor and materials sciences applications. These integrated CrossBeam registered Tools enable the observation and direct control of the FIB operation in real time. In addition to the improved accuracy and resolution the electron beam adds analytical capabilities as STEM, EDS and EBSP to the instruments. To ensure a safe and reliable operation of the instrument, a dedicated vacuum system is needed. This type of ...
This handbook provides the necessary tools for the engineer to design forced-cooled HPOF pipe-type cable systems. It represents the final objective of a major project which included an extensive research program at the Waltz Mill Forced-Cooling Test Facility. The formulas and procedures presented in this handbook are consistent with the results of this program as well as other full-scale and model investigations. Introductory material, including historical information, general design concepts and basic heat transfer and fluid dynamics theory is given for those who are unfamiliar with the fundamental principles of forced-cooling. The nucleus of the handbook consists of equations and calculating procedures for determining forced-cooled parameters and thermal/hydraulic performance levels. Both simple and sophisticated procedures have been provided, with the more complex procedures treating such areas as the thermal interaction between cable pipes ...
A method for systematically including topological degrees of freedom in perturbation theory is developed. This is not bound by the restrictions of semi-classical techniques. The Yang-Mills theory in three Euclidean dimensions is considered here. A well-defined separation of the topological and the ``spin wave'' degrees of freedom is obtained, motivated by a singular gauge. This has ``photons'' distorting the spherically symmetric magnetic fields of Dirac monopoles, and massless charged vector bosons ``W'' scattering off the latter. It is explicitly shown that the Dirac string does not contribute. The mode of the charged vector bosons with total angular momentum J=0 provides precisely the core to give a finite energy to the monopole. The radial equation for W is remarkably simplified and only two polarization states survive exactly for the anomalous magnetic moment required by the Yang-Mills interaction.
Focus Ion Beam (FIB) milling has greatly extended the utility of atom probe and TEM because it enables sample preparation with a level of dimensional control never before possible. Using FIB it is possible to extract the samples from desired and very specific locations. The artifacts associated with this sample preparation method must also be fully understood. In this work issues specifically relevant to the FIB milling of aluminum alloys are presented. After using the FIB as a sample preparation technique it is evident that gallium will concentrate in three areas of the sample: on the surface, on grain boundaries and at interphase boundaries. This work also shows that low energy Ar ion nanomilling is potentially quite effective for removing gallium implantation layers and gallium from the internal surfaces of aluminum thin foils.
... It has 2x 15L bins: one for food waste, the other for recycling, which slide out on ball bearing steel runners. Both have plastic inner buckets that can be lifted out. Supplied with fixing brackets. To fit 30cm-wide cabinets Filed Under: Top Products Tagged With: bedroom, bins, drawers, drawersshelveskitchenbins, garden, home, homegardenbedroomstorage, John Lewis, kitchen, shelves, storage ...
The behaviour of an elastomeric seal for vehicle brake Tandem master cylinder is measured and analyzed in temperature and brake fluids changed. Working conditions are simulated for different piston rod velocity and cylinder supply pressure, in temperature rising, brakefluid boundary and Nanoaluminum oxide brakefluid oxide brakefluid lubrication. The result shows that Nanoaluminum oxide brakefluid with its ball shape can highly reduce friction coefficient to avoid seal excessive wear and reduce slick slip in brake applications.
A phantom simulation imaging quality control device is described that effectively simulates one centimeter lesions, using steel ball bearings as gamma ray attenuators. The bearings are mounted in a synthetic resinous sheet in an orthogonal pattern. The phantom can provide uniformity, resolution, linearity, distortion and field size checks, all with a single exposure.
... One 20 litre and one 15 litre removable bins Quick and easy installation Slides in and out on ball bearing track W248 x D455 x H485mm In Stock Email a Friend Quantity : 㿝.95 inc VAT Segregated Bins Stacked Bins Built-In Bins Office Bins Can Crushers Bags and Liners Accessories ...
We prove that Formula Not Shown surface diffeomorphisms have symbolic extensions, i.e. topological extensions which are subshifts over a finite alphabet. Following the strategy of Downarowicz and Maass (Invent. Math. 176:617?636, 2009) we bound the local entropy of ergodic measures in terms of Lyapunov exponents. This is done by reparametrizing Bowen balls by contracting maps in a approach combining hyperbolic theory and Yomdin?s theory.
Shut Down System - 2 (SDS - 2) of TAPP-3 and 4 works on the principle of rapid injection of gadolinium nitrate poison solution into bulk moderator in calandria using high pressure helium to shut down the reactor. This is a new system, in the context of Indian PHWRs, designed, engineered, commissioned and being operated in TAPP-3 and 4. The system design incorporates passive features such as floating polyethylene ball with ball-ball seat arrangement and locked open isolation ball valves with key interlock arrangement. This arrangement eliminates active valves downstream of poison tanks during SDS - 2 actuation. A series parallel arrangement of fast acting pilot controlled air operated valves, which keep the high pressure helium isolated from poison tanks in poised state, are the only active components. During commissioning and initial period of operation of TAPP-4, problems were encountered and were resolved by suitable ...
Nanocrystalline samples of Fe_8_0Mo_2_0 and Fe_5_0Mo_5_0 alloys were prepared by the mechanical milling method. The structure, lattice parameters, and crystallite size were determined by the X-ray diffraction. The magnetic properties of the milled products were determined by the Moessbauer spectroscopy. It was observed that in the case of the Fe_8_0Mo_2_0 alloy a solid solution of Mo in Fe was formed with the lattice parameters of the Fe increasing from 0.28659 nm to 0.29240 nm and the crystallite size decreasing from 250 nm to 20 nm. In the case of the Fe_5_0Mo_5_0 alloy there were no clear changes in values of the lattice parameters of Fe and Mo during the milling process, but the crystallite size decreased from 200 to 15 nm. Moessbauer spectra revealed different magnetic phases in the machanosynthesized Fe_Mo samples. In the case of the Fe_8_0Mo_2_0 alloy, the spectrum for the milled mixture ...
Cell suspension cultures of tomato, Lycopersicon esculentum Mill. cv VFNT-Cherry, produce phytochelatins (poly[γ-glutamylcysteinyl]glycines) when exposed to cadmium. The synthesis...Full Text Available
The optimizing criterion is assumed to be the maximum net present value of the project. The following summarizes the significant conclusions. (1) Over a large range of discount rates, mining and milling of the mineral deposit at a constant cutoff grade and a constant production rate consistently results in smaller annual discounted cash flows than the optimal schedule determined by the dynamic programming model (dpm) where the cutoff grade and mining rate are allowed to vary in response to fluctuating product price. (2) With an increasing discount rate, under the dpm the annual discounted cash flows decrease at a slower rate than if the mineral inventory is mined and milled at a constant cutoff grade and a constant production rate. (3) Cuttoff grade increases only where higher equity ore is available. Thus, to maintain the mill feed requirement, the mining rate also increases. (4) Not withstanding an anamolous mineral ...
Recent studies have revealed a number of striking dependence patterns in high frequency stock price dynamics characterizing probabilistic interrelation between two consequent price increments x (push) and y (response) as described by the bivariate probability distribution P(x,y) [1,2,3,4]. There are two properties, the market mill asymmetries of P(x,y) and predictability due to nonzero z-shaped mean conditional response, that are of special importance. Main goal of the present paper is to put together a model reproducing both the z-shaped mean conditional response and the market mill asymmetry of P(x,y) with respect to the axis y=0. We develop a probabilistic model based on a multi-component ansatz for conditional distribution P(y|x) with push-dependent weights and means describing both properties. A relationship between the market mill asymmetry and predictability is discussed. A possible connection of the model to ...
After preparation on self-generated Percoll gradients, avocado (Persea americana Mill, var. Fuerte and Hass) mitochondria retain a high proportion of cyanide-insensitive respiration,...Full Text Available
... on a transgressive surface; examples from the Silurian Whirlpool Sandstone of southern Ontario, Canada. Journal of Sedimentary ... and C. J. Salas. 1991. The Lower Silurian Whirlpool Sandstone. in Cheel, ...
Focused-ion beam (FIB) milling provides rapid fabrication of individual cylindrical submicrometer channels with reproducible dimensions (#+-#5% diameters) through 8-#mu#m thick poly(methylmethacrylate) (PMMA) films. PMMA films are spincast on sacrificial Si carriers and sputter-coated with Au before the 30-kV gallium FIB milling process. By adding a trace amount of poly(ethyleneoxide) and poly(dimethylsiloxane) to the PMMA solution before casting, the films can be released for subsequent mounting in microfluidic devices to create hybrid microfluidic-nanofluidic multilevel architectures. In situ FIB sectioning demonstrates the smooth cylindrical surface within the pore. Placing a milled film in contact with an aqueous fluorescein solution fills the channel by capillary action, as verified by confocal fluorescence microscopy. Confocal fluorescence of dyed films reveals that the pores span the thickness of the PMMA film. Small ...
Workers from cotton mills were exposed to cotton dust during carding in an experimental cardroom. Cotton from different geographical locations with varying amounts of endotoxin were used. Exposure levels...Full Text Available
The following manual chapters are outlined and described: overview, boilers, juice evaporators, feed mills, refrigeration, additional energy savings potentials, emerging technologies, optimization of integrated plant energy systems, and economics. (MHR)
AT AFRICA (O.F.) AIDO1 SYMMES CREEK AT AID ALLO1 MAHONING RIVER AT ALLIANCE ALZO1 ALEXANDRIA AMDO1 AMSTERDAM ARMO1 CAPTINA CREEK AT SR 148 AT ARMSTRONG MILLS ASVO1 WALNUT CREEK...
An extracellular polysaccharide was purified from culture supernatants of Paenibacillus jamilae CP-7, a gram-positive bacillus that was isolated from compost prepared with olive mill...Full Text Available
Gravitropic asymmetry of auxin was observed in hypocotyls of tomato (Lycopersicon esculentum Mill.) soon after horizontal placement: the ratio of apically supplied [3H]IAA...Full Text Available
Hundreds of thousands of people worldwide live or work in close proximity to steel mills. Integrated steel production generates chemical pollution containing compounds that can induce genetic damage...Full Text Available
Lycopersicon esculentum Mill. cv Vedettos and Lycopersicon chmielewskii Rick, LA 1028, were exposed to two CO2 concentrations (330 or 900 microliters per...Full Text Available
Advanced techniques for focused-ion-beam (FIB) device modification have been developed for complex, multistep modifications to circuitry on planar chip technology. Applying gas-assisted etching (GAE) techniques for high-aspect-ratio milling and the selective milling of both conductive and insulating films enhances process latitude. Localized ion-beam-induced deposition of an insulating film provides reconstructive capability in previously modified areas. The application of both techniques for complex device modification on VSLI devices fabricated with CMOS process technology is reviewed. (UK).
By employing the higher dimensional version of the Wu-Yang Ansatz we obtain magnetically charged new black hole solutions in the Einstein-Yang-Mills-Lovelock (EYML) theory with second ($\\alpha2$) and third ($\\alpha3$)order parameters. These parameters, where $\\alpha2$ is also known as the Gauss-Bonnet parameter, modify the horizons (and the resulting thermodynamical properties) of the black holes. It is shown also that asymptotically, these parameters contribute to an effective cosmological constant -without cosmological constant- so that the solution behaves de-Sitter (Anti de-Sitter) like.
The use of uranium mill tailings in the foundations of dwellings has resulted in indoor radon progeny concentrations and gamma exposures in excess of levels presently allowed for the general public. An account is given of the applications of an epoxy coating on the indoor faces of the concrete foundations of three buildings in Grand Junction, Colorado. Epoxy barriers were shown to be effective for preventing radon influx into structures. Gamma exposure rates must be analyzed to ensure that buildup behind the barrier will not introduce an unacceptable gamma exposure level. The use of a sealant is especially economical in situations where structural integrity may be jeopardized by physical removal of uranium mill tailings. (author).
We consider the case of a test sphere (ball) of radius a{sub 1} rotating at constant angular velocity {omega} in an otherwise quiescent unbounded suspension of uniformly sized spheres of radii a{sub 2} dispersed in a Newtonian fluid of viscosity {mu}. To the first order in the volume fraction c of suspended spheres it is shown that when the ball is small compared with the suspended spheres the suspension does not behave as regards the hydrodynamic torque L exerted on the ball like a homogeneous Newtonian fluid characterized by the usual Einstein viscosity coefficient {mu}{sub s}={mu}(1+5/2c). Explicitly, the torque on the rotating sphere does not obey Kirchoff{close_quote}s law, L=8{pi}{mu}{sub s}a{sub 1}{sup 3}{omega} for no slip. Rather, a modified form of Kirchoff{close_quote}s law is obtained in which the Einstein coefficient of 5/2 is multiplied by a coefficient which is less than unity in magnitude and is functionally ...
Single phase amorphous Al_xHf_1_0_0_-_x alloys with a wide amorphization range (33#<=#x#<=#75) were synthesized by the solid-state interdiffusion of pure polycrystalline Al and Hf powders at room temperature using a rod-milling technique. The mechanisms of metallic glass formation and competing crystallization processes in the mechanically deformed composite powders were investigated by means of X-ray diffraction, differential thermal analysis, scanning electron microscopy and transmission electron microscopy. The numerous intimate layered composite particles of the diffusion couples that formed during the first and intermediate stages of milling (0-173 ks) are intermixed to form amorphous phase(s) upon heating to about 980 K by so-called thermally assisted solid-state amorphization (TASSA). The amorphization heat formation for the binary Al_xHf_1_0_0_-_x system via TASSA, #DELTA#H"T"A"S"S"A_a, was measured directly as a function of the ...
Three model boilers, manufactured to simulate full-size tube sheet crevices, were tested with various secondary side environments. The first was faulted with organics representative of the decomposition of humic acid. The second was faulted with sodium carbonate and sodium hydroxide, while the third was faulted with sodium sulfate and sodium hydroxide. Each model contained seven tubes, which included Alloy 600 in the mill-annealed (MA) and thermally-treated (TT) conditions and Alloy 690 in the thermally-treated condition. Two models contained Alloy 800 tubes in the mill-annealed condition and one had Alloy 800 in the mill-annealed/cold-worked/glass-bead-peened condition. Two different sizes of tubesheet crevices were used in all model boilers. In the organics-faulted boiler, tubes of Alloy 600MA, Alloy 690TT and Alloy 800MA experienced no significant intergranular attack (IGA); however, the Alloy 600TT had intergranular ...
Three model boilers, manufactured to simulate full-size tube sheet crevices, were tested with various secondary side environments. The first was faulted with organics representative of the decomposition of humic acid. The second was faulted with sodium carbonate and sodium hydroxide, while the third was faulted with sodium sulfate and sodium hydroxide. Each model contained seven tubes, which included Alloy 600 in the mill-annealed (MA) and thermally-treated (TT) conditions and Alloy 690 in the thermally-treated condition. Two models contained Alloy 800 tubes in the mill-annealed condition and one had Alloy 800 in the mill-annealed/cold-worked/glass-bead-peened condition. Two different sizes of tubesheet crevices were used in all model boilers. In the organics-faulted boiler, tubes of Alloy 600MA, Alloy 690TT and Alloy 800MA experienced no significant intergranular attack (IGA); however, the Alloy 600TT had intergranular ...
The tribo characteristics of self-lubricating 40-mm-bore ball bearings with a retainer of glass cloth-polytetrafluoroethylene (PTFE) laminate, which has elliptical pockets with a large pocket clearance, were tested under thrust loads at speeds up to 50,000 rpm, 2 million DN, in liquid hydrogen (LH2) and in liquid nitrogen (LN2). During testing, the bearing torque, outer-race temperature, and electric resistance between the inner and outer races were monitored to verify the formation and rupture of a PTFE transfer film. Testing showed that the bearings having the elliptical retainer pockets were superior to the conventional bearings with circular pockets. It was determined that, at the maximum inner race spinning velocity of about 5 m/s, a PTFE transfer film could sustain the maximum Hertz stress, up to about 2000 N/sq mm, in LH2, without severe film rupture resulting in bearing seizure. In LN2, the critical load capacity of PTFE transfer film with bearing seizure ...
A radio frequency sputtering apparatus with a pair of targets has been developed for depositing a film of uniform thickness onto a complex-geometric specimen such as the retainer of a ball bearing. The deposition characteristics of the apparatus were compared with those of the conventional sputtering apparatus. Lubrication properties of MoS/sub 2/ films made by these devices were also compared under a variety of conditions. Finally, friction and wear of MoS/sub 2/ films applied to angular-contact type ball bearings of 20 mm bore were studied in air, nitrogen and vacuo. The two-target sputtering has an advantage mentioned above. However, the films deposited by the method exhibited a rather short wear life because of the temperature rise of the substrate during ion bombardment and during the sputtering process. This temperature dependence was observed in films on those substrates that had been heated with a built-in heater during sputtering. The ...
Under severe operating conditions, such as starved lubrication, performance, service life, and reliability of rolling element bearings depend on the chemical and physical interactions between the contacting surfaces, the lubricant components, and the atmosphere. The IMKT{sup 1}, PI{sup 2}, and the imt{sup 3} have been cooperating on systematic investigations of interfacial interactions in high speed grease lubricated ball bearings. These include long time tests with complete bearings lubricated with greases of different composition under defined operating conditions, conducted at the IMKT, and chemical and physical characterizations of the running surfaces at the PI and imt. At the PI, in particular the chemical nature of the boundary layers has been investigated with time of flight secondary ion mass spectrometry (TOF-SIMS). The imt has been involved in the investigations by measuring the physical/mechanical properties of interacting surfaces at the ...
A highly reliable control rod drive mechanism (CRDM) installed inside the reactor vessel has developed for use of an advanced marine reactor. This CRDM contributes to compactness and simplicity of the reactor system, and it can eliminate the possibility of a rod ejection accident. The CRDM works in the high temperature and high pressure water - 310degC and 12 MPa, the same atmosphere as the primary loop. Driving force is produced by a synchronous motor with the rotor of a permanent magnet, which has been developed. An innovative latch mechanism using separable ball nuts can latch driving shaft connecting the control rod and de-latch it for scram. The rod position detector using a magnetostrictive wire type sensor on the principle of Wiedeman effect has been developed, accuracy of which is verified to have a detecting error within 1.2 mm. Ball bearings for thrust and radial supports in rotation have been developed to be capable of working under ...
A series of ball-on-disc wear and friction measurements were made for surfaces which have a chemical vapour deposition carbon silicon alloy layer on a carbon substrate (fine grain POCO graphite). Nitrogen ion irradiation was used to improve the wear resistance of the carbon alloy surface. For comparison, measurements were also taken for alumina against alumina. It was found that the lowest friction coefficient and lowest wear occurred for ion irradiated coated samples containing 4% Si in the alloy and that the performance was superior to that of alumina. ((orig.))
A series of ball-on-disc wear and friction measurements were made for surfaces which have a chemical vapour deposition carbon silicon alloy layer on a carbon substrate (fine grain POCO graphite). Nitrogen ion irradiation was used to improve the wear resistance of the carbon alloy surface. For comparison, measurements were also taken for alumina against alumina. It was found that the lowest friction coefficient and lowest wear occurred for ion irradiated coated samples containing 4% Si in the alloy and that the performance was superior to that of alumina. ((orig.)).
An automatic loading roller for transmitting torque in traction drive devices in manipulator arm joints includes a two-part camming device having a first cam portion rotatable in place on a shaft by an input torque and a second cam portion coaxially rotatable and translatable having a rotating drive surface thereon for engaging the driven surface of an output roller with a resultant force proportional to the torque transmitted. Complementary helical grooves in the respective cam portions interconnected through ball bearings interacting with those grooves effect the rotation and translation of the second cam portion in response to rotation of the first. 14 figs.
This patent describes an automatic loading roller for transmitting torque in traction drive devices in manipulator arm joints includes a two-part camming device having a first cam portion rotatable in place on a shaft by an input torque and a second cam portion coaxially rotatable and translatable having a rotating drive surface thereon for engaging the driven surface of an output roller with a resultant force proportional to the torque transmitted. Complementary helical grooves on the respective cam portions interconnected through ball bearings interacting with those grooves effect the rotation and translation of the second cam portion in response to rotation of the first.
The pipelines is provided for gases, particluarly helium, at temperature of about 1000/sup 0/C (pressure about 40 bar) and is used as the connection be tween a gas cooled high temperature reactor and a heat load. The pipe consists of a temperature-resistant inner tube, which is composed of several pipe sections, which are supported on ball bearings, and a gas tight pressurised outer tube. There are supports and insulation between the two tubes. The sub-claims concern fixing of and bearings for the pipe sections. The description is very detailed and supplemented by drawings.
The All Union Scientific Research Institute of Drilling Techniques has developed the SH01-195 spindle deflector designed for use with the 195 millimeter turbodrill sections in place of the standard spindle. This spindle deflector is an axial support for the turbodrill, manufactured as a separate unit that attaches to the turbosections using the standard attachment configuration for series manufactured turbodrills, using the sub for attachment to the frame and a splined half coupling for attachment to the shaft. The spindle deflector itself consists of two parts connected by a curved sub through the frame and by a double hinge to the shaft. The hinge is isolated from axial forces by mounting radial support ball bearings above and below it.
...Oster | Best sexual wellness info Best sexual wellness info Home Posts Tagged Oster Oster Professional 103 Stim-U-Lax Massager Reviews Made of 100% ball bearing construction Traditional frame design with special frame contour to fit hand and reduce hand fatigue Chrome housing and rubber hand pad Heavy-duty, single speed UL approved 120v This lightweight therapeutic massager combines the advantages of hand and mechanical massage. Its special contoured design reduces hand fatigue and its universal ...
A simple model is outlined to describe the collision of cast phenol-formaldehyde resin spheres such as the balls used in the parlor game of pocket billiards, based in part on the famous analysis of elastic collisions developed by Heinrich Hertz over 100 years ago. The analysis treats the normal and tangential components of the initial sphere's velocity independently as it collides with a stationary identical second sphere. The collective effects of these and other parameters on the trajectory of the second sphere are provided in the conclusions.
Silicon nitride hybrid ball bearings used in high temperature applications undergo mechanical and environmental degradation. To study the surface chemistry of silicon nitride, a CAChe{trademark} Worksystem* has been used to generate the clusters and corresponding transmission vibrational spectra of silicon nitride. In the present study, the effect of surface conditions on the surface chemistry and wear degradation of silicon nitride was evaluated. Infrared reflection spectroscopy (IRRS) used to determine molecular orientations shows a difference in reflectance spectra for fractured and as-received.
Fe-doped MnO2 with a hollow sea urchin-like ball chain shape was first synthesized under a high magnetic field of 10 T. The formation mechanism was investigated and discussed in detail. The synthesized samples were characterized by XRD, SEM, TEM, EMPA, and vector network analysis. By doping MnO2 with Fe, the relative complex permittivity of MnO2 and its corresponding loss tangent clearly decreases, but its relative complex permeability and its corresponding loss tangent markedly increases. Moreover, the theoretically calculated values of reflection loss show that with increasing the Fe content, the as-prepared Fe-doped MnO2 exhibits good microwave absorption capability. -- Graphical Abstract: Fe-doped MnO2 with a hollow sea urchin-like ball chain shape was first synthesized in a high magnetic field of 10 T via a simple chemical process. Display Omitted Highlights: ? Fe-doped MnO2 with a hollow sea urchin-like ball chain ...
This paper describes high speed rolling and gauge control in cold tandem mill for ultra-thin gauge strip at the Chiba Works of Kawasaki Steel Corporation. To improve the plate-out property of rolling oil, cationic polymeric coagulant was prepared. Rolling oil with cohesion independent of inorganic inclusions or phosphatide was developed, to improve the lubrication for cold rolling, remarkably. In addition, a low-cost Ti-enhanced work roll having high wear resistance and excellent grindability was developed. Rolling can be conducted at the optimal rolling roughness and operation can be performed at the highest rolling speed independent of the rolling treatment amount. Rolling speed at 2800 m/min was confirmed by developing the rolling oil with excellent lubrication and the work roll having high wear resistance. For the improvement of strip thickness accuracy at the steady state rolling, use of the backup roll as roller bearing was more effective rather than the ...
This study evaluates the degree to which surface impoundments at licensed facilities comply with significant changes in NRC requirements initiated by enactment of EPA's final environmental standards for uranium recovery facilities (40 CFR Part 192). Impoundment liner requirements, ground-water protection standards, ground-water monitoring and corrective action programs, and site closure standards are the most significant regulatory modifications. The compliance status of 30 conventional mills and 31 in-situ mines is determined from a review of Nuclear Regulatory Commission and agreement state docket files through November, 1983. Results of this review show that a majority of conventional uranium mill tailings management systems are deficient with respect to liner requirements for new impoundments or proposed expansions to existing impoundments, as well as with respect to some aspects of ground-water monitoring and compliance programs. ...
Focused ion beam (FIB) milling techniques are presented aiming at the manipulation of both tin dioxide (SnO_2) inverted opals and polystyrene (PS) direct opals. Different SnO_2 opals are considered in order to estimate the regularity of their bulk after the production. A SnO_2 mesoporous monolith is FIB micromachined to make it suitable for optical applications. PS direct opals are structured by FIB milling at different scales. Ordered arrays of PS opals are modified by selectively removing a single sphere. In performing this task, we discuss the effects on the FIB milling due to the gas-assisted enhanced etching and to the binding of the nearest neighbours. Techniques to achieve imaging of PS opals in absence of a conductive coating are also brought up. Furthermore, isolated PS spheres are drilled with or without enhanced etching in order to produce controlled defects on them. The FIB-assisted manipulations we show may ...
The most recently developed control technologies in a hot strip mill are described. Preview AGC has been developed with a preview control synthesis. It controls roll gaps by using the previous information of disturbances. The disturbances which are concerned are derived from the rolling force, the roll gap and the thickness of a previous stand. The thickness accuracy and the availability of mill have been improved by this technology. An on-line roll grinding (ORG) system with an on-line roll profile meter (OPM) has been developed for the purpose of achieving schedule-free rolling. The ORG smooths the worn and roughed surface of a work roll and OPM can measure the profile of a revolving roll without contact. The data obtained by the OPM are given as feedback information to the ORG. As a result, grinding accuracy has been improved and rolling restriction on width has been relaxed widely. (author)
We have researched several new focused ion beam (FIB) micro-fabrication techniques that offer control of feature shape and the ability to accurately define features onto nonplanar substrates. These FIB-based processes are considered useful for prototyping, reverse engineering, and small-lot manufacturing. Ion beam-based techniques have been developed for defining features in miniature, nonplanar substrates. We demonstrate helices in cylindrical substrates having diameters from 100 {micro}m to 3 mm. Ion beam lathe processes sputter-define 10-{micro}m wide features in cylindrical substrates and tubes. For larger substrates, we combine focused ion beam milling with ultra-precision lathe turning techniques to accurately define 25-100 {micro}m features over many meters of path length. In several cases, we combine the feature defining capability of focused ion beam bombardment with additive techniques such as evaporation, sputter deposition and electroplating in order to ...
This work deals with a study on estimation of energy consumption in eight readily defined unit operations of cashew nut processing. Data for analysis were collected from nine cashew nut mills stratified into small, medium and large categories to represent different mechanization levels. Series of equations were developed to easily compute requirements of electricity, fuel and labour for each of the unit operations. The computation of energy use was done using spreadsheet program on Microsoft Excel. The results of application test of the equations show that the total energy intensity in the cashew nut mills varied between 0.21 and 1.161MJ/kg. Electrical energy intensity varied between 0.0052 and 0.029MJ/kg, while thermal energy intensity varied from 0.085 to 1.064MJ/kg. The two identified energy intensive operations in cashew nut processing are cashew nut drying and cashew nut roasting, altogether accounting for over 85% of the total energy ...
The objectives of this project were to develop technologies to manufacture self-reducing briquettes out of waste iron oxides and to recycle them in an electric arc furnace or a cupola furnace. CRM has investigated and determined the optimal characteristics (binder, size, grain size, compositions and activator for the reduction reaction) for briquettes containing mixtures of mill scales, mill sludges, electric arc furnace (EAF) dust and coal as reduction agent. The goal of obtaining briquettes, in which iron oxides are totally reduced when these briquettes are loaded with the scrap into an electric arc furnace, was achieved. Trials at ProfilARBED have shown that it is possible to recycle mill and EAF by-products conditioned in self-reducing briquettes in an electric arc furnace without influence on the performance and on the environment. The iron content of the slag does not increase as the iron of the by-product is almost ...
Anaerobic treatment of olive oil mill wastewaters (COD up to 220 kg/cubic m) is feasible, and the most promising results were obtained on UASB reactors, both at laboratory and pilot scale (tank capacity 15 litres and 5 cubic m), fed on diluted waste (COD = 13-18 kg/cubic m). Volumetric loading rates ranging from 16-21.5 kg COD/cubic m/day and 70% removal efficiencies were obtained with these digesters. Start-up of UASB reactors fed on olive oil mill waste is a delicate step which still has to be fully controlled and optimized. The best results were obtained by starting with very diluted waste (COD = 5 kg/cubic m). Granulation of the sludge, as achieved in Dutch UASB digesters fed on sugar beet wastewaters, was not obtained, but, even so, the settleability of the sludge was very good. 22 references.
A biogenic method for the treatment of uranium mill effluents containing toxic amounts of Mn"2 and "2"2"6Ra is described. The acidic tailings from the uranium mills are generally neutralised with lime and the overflow waters from tailing ponds at the discharge point, consisting of Mn"2"+ (>10 mg l"-"1) and "2"2"6Ra (> 3.0 pCi l"-"1), need further treatment before disposing off to the public utility. Arthrobacter sp. has been used for precipitating Mn"2"+ as hydrous oxide of manganes (MnO_2#centre dot#nH_2O) and along with "2"2"6Ra also gets precipitated. The effluent after bacterial treatment consisted of Mn"2"+ and "2"2"6Ra within the range of allowed concentrations as per the I.C.R.P. (International Committee of Radiological Protection) and MPC (maximum permissible concentration) standards (Mn"2"+ 95% of "2"2"6Ra could be precipitated using this method. (author). 11 refs.; 4 figs.; 4 tabs.
A full scale co-digestion system for sludge and Olive oil mill effluent (OME) and a regional sludge management plan has been set-up to solve urgent environmental problems, modifying an existing cold municipal digester, by means of simple and effective technology. Monitoring of the full scale system demonstrated good compatibility between OME and sludge, up to 20% mixture, and high removal of organics compounds. Coagulant compounds present in OME (mainly Fats), promoted aggregation and settling of anaerobic sludge and also its acetoclastic activity, minimizing the load returned to the wastewater treatment line and improving also the activated sludge system. The co-digestion of OME with sludge agreed the project purposes, and produced large quantity of biogas and electric energy.
Ford, Bacon, Davis Utah Inc. has reevaluated the Spook site in order to revise the December 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings 48 mi northeast of Casper, in Converse County, Wyoming. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 187,000 tons of tailings at the Spook site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors.
In this paper, research on pass schedule of tandem cold mill (TCM) is carried out. According to load (reduction, rolling force, motor power) balance, non-linear equations set with variables of inter-stand thickness is constructed. The pass schedule optimization is carried out by solving the non-linear equations set. As the traditional method, the Newton-Raphson method is used for solving the non-linear equations set. In this paper a new simple method is brought up. On basis of the monotone relations between thickness and load, the inter-stands thickness is adjusted dynamically. The solution of non-linear equations set can be converged by iterative calculation. This method can avoid the derivative calculation used by traditional method. So, this method is simple and calculation speed is high. It is suitable for on-line control. (author)
In this paper, research on pass schedule of tandem cold mill (TCM) is carried out. According to load (reduction, rolling force, motor power) balance, non-linear equations set with variables of inter-stand thickness is constructed. The pass schedule optimization is carried out by solving the non-linear equations set. As the traditional method, the Newton-Raphson method is used for solving the non-linear equations set. In this paper a new simple method is brought up. On basis of the monotone relations between thickness and load, the inter-stands thickness is adjusted dynamically. The solution of non-linear equations set can be converged by iterative calculation. This method can avoid the derivative calculation used by traditional method. So, this method is simple and calculation speed is high. It is suitable for on-line control. (author)
A kinetic study of the degradation by ozone of eight phenolic acids present in wastewaters from olive oil mills has been performed by using a competition kinetic method. The selected phenolic acids are: caffeic, p-coumaric, syringic, vanillic, 3,4,5-trimethoxybenzoic, veratric, p-hydroxy-benzoic, and protocatechuic. The influence of the operating variables (temperature, pH, and ozone partial pressure in the gas stream) is established, and the stoichiometric ratios for the individual direct reactions between ozone and each acid are determined. Once the reaction rate constants are evaluated, they are correlated as a function of temperature and pH into kinetic expressions which are provided for every phenolic acid. The global process occurs in the fast and pseudo-first-order kinetic regime of absorption, a condition required by the competition model to be used.
Nomographs that calculate the threshold values of surface fire parameters which lead to crown fire initiation were created by linking two separate fire behavior models: Van Wagner?s crown fire ignition criteria and Byram?s surface fire model. The nomographs were also based on the existing surface (fuel load, fuel heat content) and canopy (foliar moisture content, live crown base height) fuel models of Aleppo (Pinus halepensis Mill.) pine forests of Mediterranean Greece. The most important fire parameters for crown fire initiation that are calculated by the nomographs are the critical flame length and the forward spread rate of the surface fire. These parameters are readily observable in the field during fires. The nomographs provide a judicious way to assess whether a crown fire is likely ...
In this work, we report for the first time on the analysis of genetic diversity within a set of 36 Tunisian Opuntia ficus indica (L.) Mill. ecotypes using RAPD markers.Random decamer primers were screened to assess their ability to detect polymorphisms in this plant crop. Thirty-nine RAPD markers were revealed and used to survey the genetic diversity at the DNA level and to establish relationships.Consequently, considerable genetic diversity was detected and the UPGMA analysis permitted the discrimination of all the genotypes and enabled their sorting into thirteen groups. The accession `R Sbiba inerme' was significantly divergent from all tested genotypes. In addition, as shown by the clustering the tested genotypes did not significantly diverge, though originating from different localiti...
Modeling is performed for focused-ion-beam (FIB) sputtering and redeposition on trench sidewalls in a steady state approximation. Calculations are carried out to demonstrate the sputtered surface profile under known parameters such as sputtering yield as a function of ion incident angle, the FIB current density profile, and the FIB scan speed. It is found that a steplike slope with a gradient angle of {theta}{sub 0} is formed at the FIB bombarding position. Furthermore, the redeposition flux on the sidewalls is calculated as a function of {theta}{sub 0} for the FIB trench milling assuming the cosine law for the angular distribution of the sputtered atom. The redeposition will be more accurately predictable and controllable when more information about these assumptions is obtained.
Modeling is performed for focused-ion-beam (FIB) sputtering and redeposition on trench sidewalls in a steady state approximation. Calculations are carried out to demonstrate the sputtered surface profile under known parameters such as sputtering yield as a function of ion incident angle, the FIB current density profile, and the FIB scan speed. It is found that a steplike slope with a gradient angle of #theta#_0 is formed at the FIB bombarding position. Furthermore, the redeposition flux on the sidewalls is calculated as a function of #theta#_0 for the FIB trench milling assuming the cosine law for the angular distribution of the sputtered atom. The redeposition will be more accurately predictable and controllable when more information about these assumptions is obtained.
A concentric reducer tube, which was a part of the top exit roughing hydraulic descaler in a hot strip mill failed prematurely under working pressure. A detailed metallurgical investigation comprising physical examination, optical microscopy, scanning electron microscopy, and electron probe microanalysis was carried out to find out the genesis of the failure. Physical examination revealed cracks located symmetrically around the circumference of the tube that ran along its full length, up to the weld beads at both ends. Optical microscopy of etched samples revealed a banded ferrite-pearlite structure and the existence of forging folds near the change-in-section(160? fillets). Cracks were found to initiate from these forging folds. No structural abnormalities were found in the weld beads and...
Ford, Bacon and Davis Utah Inc. has reevaluated the Tuba City site in order to revise the March 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Tuba City, Arizona. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 0.8 million tons of tailings at the Tuba City site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors.
Rice husk generated as a by-product of rice processing is an important energy resource. The availability of this resource in India has been assessed and the technologies for exploitation of its energy potential in rice processing industry discussed. Nomographs have been developed for estimation of the husk required to meet the energy demand of parboiling, drying and milling operations. The unit cost of electricity using rice husk gasifier-based power generation systems has been calculated and its financial feasibility assessed in comparison with utility-supplied and diesel-generated electricity. With the cost and efficiency data assumed here, the unit cost of electricity produced by rice husk gasifier-dual fuel engine-generator system varies between Rs 2/kWh and Rs 7/kWh. (author)
Rice husk generated as a by-product of rice processing is an important energy resource. The availability of this resource in India has been assessed and the technologies for exploitation of its energy potential in the rice processing industry discussed. Nomographs have been developed for estimation of the husk required to meet the energy of parboiling, drying and milling operations. The unit cost of electricity using rice husk gasifier-based power generation systems has been calculated and its financial feasibility assessed in comparison with utility-supplied and diesel-generated electricity. With the cost and efficiency data assumed here, the unit cost of electricity produced by rice husk gasifier-dual fuel engine-generator system varies between Rs 2/kWh and Rs 7/kWh. (35 Rs approximates to SUS 1.). (author)
Starting from the generalized Konishi anomaly equations at the non-perturbative level, we demonstrate that the algebraic consistency of the quantum chiral ring of the N=1 super Yang-Mills theory with gauge group U(N), one adjoint chiral superfield X and N_f<=2N flavours of quarks implies that the periods of the meromorphic one-form Tr dz/(z-X) must be quantized. This shows in particular that identities in the open string description of the theory, that follow from the fact that gauge invariant observables are expressed in terms of gauge variant building blocks, are mapped onto non-trivial dynamical equations in the closed string description.
... Materials (PREM) Synopsis of Program: The objective of PREM is to enhance diversity in materials ... careers in materials research. The Partnerships for Research and Education in Materials (PREM ...
... Materials (PREM) Synopsis of Program: The objective of PREM is to enhance diversity in materials ... careers in materials research.The Partnerships for Research and Education in Materials (PREM ...
... centers in materials research. MRSECs address fundamental materials research topics of intellectual ... in materials research. II. PROGRAM DESCRIPTION MRSECs are supported by NSF to undertake materials ...
... Materials Research - Major Instrumentation Project (IMR-MIP) program in the Division of Materials ... for materials preparation and characterization essential for researchers studying materials in a ...
... Instrumentation for Materials Research (IMR) Division of Materials Research Synopsis of Program ... for Materials Research (IMR) program in the Division of Materials Research (DMR) is designed to ...
... Materials Development Program TECHNOLOGY EDUCATION INSTRUCTIONAL MATERIALS Elementary - High School ... of technology education materials through its Instructional Materials Development (IMD) program. The ...
... materials science and engineering, condensed-matter or materials physics, solid-state or materials ... include materials theory, condensed-matter and materials physics, solid-state and materials ...
... Although the rest of the country is less affected, if UK annual feeding and milling volumes of wheat are approximately 120,000t the drought will inevitably result in a shortfall. Looking back at the 2010 season the organic arable market performed strongly, with average feed wheat values since Christmas of 𧷐/tonne - 䀆/t higher then the same period last year. This provided a profitable ...
Soil placed over any sealant/barrier system can provide a protective mantle if the soil is not lost by erosion. Vegetation is an attractive choice for controlling erosion because it can provide an economical self-renewing cover that serves to reduce erosion by both wind and water. The objective of this research and development effort is to select and test vegetation strategies, including the choice of species and methods for revegetation that are compatible with sealant/barrier systems and are suited to soils and climates at inactive uranium mill tailings sites.
Reflective diffraction grating. A focused ion beam (FIB) micromilling apparatus is used to store color images in a durable medium by milling away portions of the surface of the medium to produce a reflective diffraction grating with blazed pits. The images are retrieved by exposing the surface of the grating to polychromatic light from a particular incident bearing and observing the light reflected by the surface from specified reception bearing.
It has been shown that mechanical milling of iron in water results in formation of nanocrystalline magnetite Fe3O4 with an average particle size of 0.6 ?m, saturation magnetization of 77 Am2/kg and coercivity of ?150 A/cm. Along with magnetite, an antiferromagnetic Fe-O phase (?10 wt%), which is an aggregate of small iron-oxygen clusters forms.
...org/ (1 vote) defends the native forest ecosystems and communities of the Southeast United States which are threatened by industrial scale clearcutting to feed chip mills Added: Jan. 20, 2001 | Rate It Don't Buy SFI http://www.dontbuysfi.com/home/ (2 votes) campaign to show the \\
The continuous bioprocessing of simulated steam-stripped sulfite pulp mill evaporator condensates using Candida utilis to produce single cell protein has been studied. At 32 degrees C, processing can be conducted at space velocities of up to 0.43 hr/sup -1/ with over 90% removal of acetic acid present at an initial concentration of 2 g/liter. (Refs. 16).
This study analyzes the economic impact that could result from the application of effluent standards and limitations issued under Sections 301, 304, 306, 307 of the Clean Water Act to the pulp, paper, and paperboard industry, including builders' paper and roofing felt manufacturing.
The engineering and economic feasibility of using the geothermal resources in East Mesa, California, in a new corn processing plant is evaluated. Institutional barriers were also identified and evaluated. Several alternative plant designs which used geothermal energy were developed. A capital cost estimate and rate of return type of economic analysis were performed to evaluate each alternative. (MHR)
Total and net energies used harvesting 30-cm billets at 8 t/h were 1 and 0.3 kW x h/t, respectively. Harvested crop had 4% leaves, a 70% mass fraction of billets 30-40 cm long, and a 49/sup 0/ angle of repose. A self-unloading forage wagon with beaters and controls metered billets at 1.5 t/h to feed a juice-expression mill.
This paper reports the results of a fine-probe EDS microanalytical study of cellular precipitation in a Cu-Ti binary alloy. Compositional profiles across the solute depleted Cu-rich FCC lamellae and the Cu_4Ti lamellae within isothermally formed cellular colonies were measured in a FEG-TEM from thin-foil specimens prepared by conventional electropolishing and by a technique using a Ga"+ focused ion-beam (FIB). The Cliff-Lorimer ratio method, with an absorption correction, was employed to quantify the compositions. Two FIB samples were prepared with different orientations of the lamellae with respect to the ion-milling direction. The compositional profiles across the Cu-rich FCC lamellae and the Cu_4Ti compound lamellae in both the FIB-prepared samples and the electropolished sample were, within experimental error, numerically equivalent. The composition of the Cu_4Ti compound phase lamellae was very close to the ideal stoichiometric composition of 20 at% Ti. It is ...
Using the manifestly causal gluon propagator in the light-cone gauge, we evaluate two one-loop Feynman integrals which appear in the computation of the three-gluon vertex correction in the two-component formalism of the Yang-Mills gauge fields. We conclude that they both are finite for {omega} -> 2, where {omega} is the dimensional regulator. They belong to a class of finite one-loop light-cone integrals. (author). 7 refs.
Materials World Network: Cooperative Activity in Materials Research between US Investigators and ... Program Title: Materials World Network: Cooperative Activity in Materials Research between US ...
Materials World Network: Cooperative Activity in Materials Research between US Investigators and ... Program Title: Materials World Network: Cooperative Activity in Materials Research between US ...
This definitive reference is organized in an easy-to-follow format based on materials properties. It features new and existing data verified through major professional societies in the materials fields, such as ASM International and the American Ceramic Society. The third edition has been significantly expanded, most notably by the addition of new tabular material for a wide range of nonferrous alloys and various materials. The contents include: Structure of materials; Composition of materials; Phase diagram sources; Thermodynamic and kinetic data; Thermal properties of materials; Mechanical properties of materials; Electrical properties of materials; Optical properties of materials; Chemical properties of materials.
... The drop in pay, with mounting medical bills and a curve ball in their personal life, led Mr. Flake and his wife, Amy, to exhaust their savings. As they shifted spending to credit cards their debt mounted, and conversations about retirement ... In October 2008, they learned that a relative of hers with an 8-month-old son was going to prison. If the Flakes could not take the baby, he would be placed in foster care. The Flakes did some soul searching and decided to seek custody of ...) 1 2 Next Page »A version of this article appeared in print on March 24, 2011, on page F4 of the New York edition. Sign In to E-Mail Print Single Page Reprints Connect with The New York Times on Facebook. Get Free E-mail Alerts on These Topics Retirement Personal ...
Recent improvements in cell purification and transplantation techniques have contributed to the identification of cell populations known as tumor-initiating cells (TIC). This discovery has led to the -cancer stem cell hierarchy- concept, which holds that tumors are organized as a hierarchy of malignant tissues sustained by such TIC. However, this concept remains controversial. In this review, we examine recent advances in cancer stem cell research that have been generated from studies of Philadelphia (Ph) chromosome-positive leukemia. The abnormal Ph chromosome, which arises from a translocation creating the BCR-ABL1 fusion gene, is most commonly associated with chronic myelogenous leukemia (CML) and precursor B cell acute lymphoblastic leukemia (B-ALL). Examination of the pathophysiology ...
Focused Ion Beam (FIB) technology has become an indispensable enabling tool for micro nano fabrications. One important application is to use FIB for patterning conducting nanowires of metals down to a few tens of nanometre for applications such as interconnects, heaters and temperature nanosensors. A series of experiments on Au nanowires fabricated by FIB on SixNy membrane show that nanowires with width 50nm have structural instabilities. These are liquid like and first show-up as undulations in nanowire width with clearly defined wave lengths. For smaller widths (20nm) the instabilities grow and the wires eventually break-up into spherical balls. Further experiments show that the nanowires can be made stable to smaller widths by the use of a Cr underlayer to enhance surface wetting. The o...
A totally-enclosed, fan-cooled, rib-cooled type induction motor is adopted for an exhauster which is to be installed in a ventilation station for dust catcher in a tunnel. It has the highest capacity in Japan for the above purpose, and is provided with a cooling fan inside to recirculate cooled air, thereby improving cooling efficiency and reducing size and weight. Three-row combined angular ball bearings are used as the thrust bearings, and grease lubrication system is adopted to simplify the inspection/maintenance works. It is to be delivered to Japan Highway Public Corporation's Shizuoka Construction Bureau, Yaizu site office. Its electric specifications are 455 kW, 440 V, 890 A and 510 rpm, and its mechanical specifications are thrust load: 16 kN and impeller load: 7.2 kN. (translated by NEDO)
The effects of group structures and weighting functions on neutron penetration through a thick Na-Fe geometry are studied. The recommended broad-group (61-neutron/23-gamma-ray) and few-group (22-neutron/10-gamma-ray) structures are tailored to the sodium and iron resonances, windows, and capture gamma-ray spectra. The best weighting functions are shown to be fine-group fluxes selected from a few key locations in the geometry. These group structures and weighting functions, relative to existing group structures and conventional weighting functions, improve the accuracy of the computed 61-neutron-group Bonner ball responses by up to one hundred percent and of the computed 22-neutron-group results by up to six hundred percent.
Excited states in the T_z=(1/2) nucleus "8"5Mo have been observed for the first time with the reaction "5"8Ni("3"2S,#alpha#n#gamma#) at 105 MeV. #gamma#-ray transitions in this nucleus have been assigned unambiguously by combining the information from the GASP #gamma#-ray array, the ISIS silicon ball, and the n-Ring neutron detector. Two band structures have been observed in this nucleus; they continue the smooth evolution of the known bands from the lighter N=43 isotones and have been tentatively assigned spins and parity on this basis. After reaching a maximum of collectivity at "8"3Zr, the trend with increasing mass is reversed, showing a smaller collectivity at "8"5Mo. The rotational behavior of the observed bands is discussed on the basis of the projected shell model calculations.
This introductory paper surveys potential sources of electric magnetic, and electro-magnetic fields. Various cases are discussed to exemplify the total frequency range: nuclear magnetic resonance tomography, high-voltage transmission lines, transformer stations, effect lighting balls, military transmitters, transmitter towers of the Postal Services and other operators, mobile radiotelephone equipment, large broadcasting transmitters, radar radiation, high-frequency heat therapy. There is evidence suggesting that electric, magnetic and electro-magnetic fields may possibly represent a certain nuisance or health hazard even at field strength occuring in equipment used for every-day-life purposes, with an emphasis on their possible actions and effects in children and adolescents. The author discusses, in conclusion, the aerial equipment ordinance issued by Lower Saxony. (Uhe).
Butter-fly valves are advantageous over gate, globe, plug, and ball valves in a variety of installations, particularly in the large sizes. The purpose of this project development of linear flow rate control system for eccentric butter-fly valve (intelligent butter-fly valve system). The intelligent butter-fly valve system consist of a valve body, micro controller. The micro controller consist of torque control system, pressure censor, worm and worm gear and communication line etc. The characteristics of intelligent butter-fly valve system as follows: Linear flow rate control function. Digital remote control function. guard function. Self-checking function. (author)
In order to suppress resonance vibrations of a rotor-shaft of rotating machinery, a rotor-shaft system elastically supported by ball bearings which are installed in electromagnetic actuators are proposed and the design method of some compensatory circuits in the controller to control the electromagnetic actuators in the system are explained. These actuators are controlled by the analog PID (proportional, integral, and derivative) controller. The compensation for nonlinearity of electromagnetic force, the negative stiffness of electromagnet, and the time lag of the coil current are discussed and the effective control circuits are proposed. The rotor-shaft system is replaced by the equivalent two-degree-of-freedom system and both impulse and frequency responses are numerically simulated for several parameters of PD-controller gain. By applying the principle of dynamic absorbers, optimum parameters are calculated. The gains of the control circuit are adjusted to give ...
A six-axis active vibration isolation system (AVIS) is designed by using the direct driven guide and ball contact mechanisms in order to have no cross-coupling between actuators. The point contact configuration gives an advantage of having an easy assembly of eight voice coil actuators to an upper and a base plate. A voice coil actuator is used since it can provide a large displacement and sufficient bandwidth required for vibration control. The AVIS is controlled considering the effect of flexible vibration mode in the upper plate and velocity sensor dynamics. A loop shaping technique and phase margin condition are applied to design a vibration controller. The performances of the AVIS are investigated in the frequency domain and finally validated by comparing with the passive isolation system. The scanning profiles of the specimen are compared together by using the atomic force microscope. The robustness of the AVIS is verified by showing the impulse response. ...
Spiral orbit tribometry friction tests performed on Ni-rich Ni55Ti45 titanium ball bearings indicate that this alloy is a promising candidate for future aerospace bearing applications. Microstructural characterization of the bearing specimens was performed using transmission electron microscopy and energy dispersive spectroscopy, with NiTi, Ni4Ti3, Ni3Ti, and Ni2Ti4Ox phases identified within the microstructure of the alloy. Density functional theory was applied to predict the electronic structure of the NixTiy phases, including the band structure and site projected density of states. Ultraviolet photoemission spectroscopy was used to verify the density of states results from the density functional theory calculations, with good agreement observed between experiment and theory.
For years rock bit performance has been progressively improved by many innovative changes to the design of both the bit cutting structure and the bearing. The changes have offered increased footage per bit and reduced cost per foot of hole through longer bit life and/or faster penetration rate. Efforts to assist the industry in drilling deeper thru hard abrasive rocks such as cherts of West Texas, conglomerated of the Rockies and bromides of Oklahoma led to a major breakthrough in rock bit design - the development of the tungsten carbide cutting structure. When properly applied the bit far exceeded that of the non-sealed ball and roller bearing being used at the time. The bearing failure mode was one of severe race spalling and abrasive wear influenced by the drilling fluid entering the bearing.
Computed tomography (CT) has been incorporated in an industrial Diode-Array Digital Radiography (DADR) system. An input data size of 512 pixel points x 400 projections yielded a 400x400 output image matrix. Reconstruction algorithms used are the filtered backprojection (FBP) and the direct Fourier reconstruction (DFR). Various filters were used in the FBP reconstruction process and their effects on image quality were evaluated. A spatial resolution of 100 {mu}m was measured with a block of plates and a minimum detectable feature size in the range of 10-100 {mu}m was measured using thin wires. Industrial specimens imaged have included ceramic samples, ball bearings and integrated circuits. A number of engineering problems have been solved, such as adjustment of the X-ray source, centering of the rotator spindle in the view field and beam-hardening corrections. (orig.).
NSF-NIST Interaction in Chemistry, Materials Research, Molecular Biosciences, Bioengineering, and ... Laboratory (CSTL). Materials research is centralized in the Materials Science and Engineering ...
A method is described for immobilizing or solidifying waste material, which includes blending the waste material with powdered metal and subjecting the mixture of waste material and powdered metal to high pressure. (author).
... Schioler (703) 306-1836 lschiole@nsf.gov This material is available primarily for archival purposes ... of superconducting materials. Colossal magnetoresistance materials are those in which the electrical ...
... of this material is, however, outside the currently approved earth fill materials collection area ... fill material suitable for its intended use. The currently approved site contains material that is ...
Some of the Indian pressurized heavy water reactors (PHWRs) which use Stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit have encountered high radiation fields in the moderator system due to "6"0Co. Release of particulate Stellite is responsible for the hotspots in addition to the general uniform contamination of internal surfaces with "6"0Co. Extensive laboratory studies have shown that it is possible to dissolve these Stellite particles by adopting a three-step redox process with permanganic acid as the oxidizing agent. These investigations with inactive Stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The susceptibility of Stellite to corrode or dissolve was found to depend on the concentration of the permanganate, pH and temperature of the ...
This work describes the use of volatile halocarbons in a pulp mill effluent, including chloroform, bromodichloromethane, and tri- and tetrachloroethylene, as tracers for the distribution and movements of effluent currents in a receiving water bay (Jackfish Bay) on the northern shore of Lake Superior. The results indicate the simplicity and usefulness of the technique and the significantly improved resolution of effluent plume delineation over the customary use of conductance profiles. Concentration patterns of the effluent volatiles suggest counterclockwise circulation of bay water that mixes with inflowing lake water at the eastern reach of the outer bay. The distribution of volatile contaminants is governed by the thermal regime of the receiving waters. During the summer months, the effluent plume wedges between the thermocline and epilimnion, mixing into the surface waters as the distance from the input source increases. In the fall, the colder effluent plume ...
Annona reticulata L. possesses many traits desirable in other edible annonas, and hybridization is the simplest means to combine desirable features of related species. In this study, A. reticulata was hybridized with atemoya (A. cherimola Mill.??A. squamosa L.), and 250 trispecies hybrids were studied for 28 traits (12 tree traits and 16 fruit traits) with the objective of salvaging useful genes from the three edible annonas and determining the extent of variation in the progeny. The heterozygous nature of Annona spp. and simultaneous segregation of three distant genomes resulted in a tremendous heterogeneity in the progenies. The fitness of the progenies ranged from very vigorous to very weak, with a wide range of values for tree height (1.75?5.9?m), canopy spread (1.15?5.07?m) and trunk...
With the aim of studying the magnetic properties of reduced-dimensionality magnetic systems we have patterned 250 nm- and 500 nm-size square elements on Fe/NiO layers by 30 keV Ga{sup +} focused ion beam (FIB) milling, varying beam current and pixel dwell time. By high resolution scanning electron microscope (SEM) imaging and atomic force microscopy (AFM) analysis we found that island size decreases from the nominal value by increasing the beam current and features sharpness improves on increasing the dwell time. The top surface of the isolated features has a pronounced edge bending which may be as high as 9 nm with respect to the flat inner area of the island and decreases as dwell time grows. By varying the ion fluence we found that such a shape is related to a surface swelling effect occurring at low ion fluence in the irradiated areas. The swelling-related damage at the edges is expected to influence the magnetic properties of the patterned features.
With the aim of studying the magnetic properties of reduced-dimensionality magnetic systems we have patterned 250 nm- and 500 nm-size square elements on Fe/NiO layers by 30 keV Ga"+ focused ion beam (FIB) milling, varying beam current and pixel dwell time. By high resolution scanning electron microscope (SEM) imaging and atomic force microscopy (AFM) analysis we found that island size decreases from the nominal value by increasing the beam current and features sharpness improves on increasing the dwell time. The top surface of the isolated features has a pronounced edge bending which may be as high as 9 nm with respect to the flat inner area of the island and decreases as dwell time grows. By varying the ion fluence we found that such a shape is related to a surface swelling effect occurring at low ion fluence in the irradiated areas. The swelling-related damage at the edges is expected to influence the magnetic properties of the patterned features.
Repassivation behavior and IGA resistance of nickel base alloys containing 0#approx#30 wt% chromium was investigated in high temperature acid sulfate solution. (1) The repassivation rate was increased with increasing chromium content. And so the amounts of charge caused by the metal dissolution were decreased with increasing chromium content. (2) Mill-annealed Alloy 600 suffered IGA at low pH environment below about 3.5 at the fixed potentials above the corrosion potential in 10%Na_2SO_4+H_2SO_4 solution at 598K. On the other hand, thermally-treated Alloy 690 was hard to occur IGA at low pH environments which mill-annealed Alloy 600 occurred IGA. (3) It was considered that the reason, why nickel base alloys containing high chromium content such as Alloy 690 (60%Ni-30%Cr-10%Fe) had high IGA/SCC resistance in high temperature acidic solution containing sulfate ion, is due to both the promotion of the repassivation and the suppression of the film ...
Lutein is a yellow pigment found in common foods that promotes the health of eyes and skin and is associated with reduced risk of age-related macular degeneration and cataracts. In the present study, selected high-lutein wheat and corn were milled into wholegrain flours by two mills to improve flour uniformity. The high-lutein and lutein-fortified wholegrain flours were processed into breads, cookies, and muffins to study lutein stability during baking and subsequent storage. Lutein and its isomers were separated, identified, and quantified by LC-UV/vis and LC-MS following extraction with water-saturated 1-butanol. Baking resulted in a significant reduction in all-trans-lutein and the formation of cis-lutein and cis-zeaxanthin isomers. Subsequent storage at ambient temperature had a slight impact on the content of all-trans-lutein. Effects of processing were more pronounced in lutein-fortified products, and the degradation rate of lutein was ...
The production of the uranium mine Zirovski Vrh ceased in 1990. The main remaining problem of the remadiation are mine and mill tailings. The uranium mine Zirovski Vrh has one mill tailings site Borst and one waste pile Jazbec. According to the Act on protection against ionising radiation and nuclear safety which was adopted by the Parliament in 2002, they are classified as radiation facilities. Slovenian Nuclear Safety Administration (SNSA) is authorised for issuing a mandatory consent to mining work. The SNSA prepared the initial proposal of content of the safety report for the mine waste pile Jazbec. In 2005, according to the detailed content of this document, the public company Zirovski Vrh Ltd prepared the safety report which was examined by an authorised expert for radiation and nuclear safety. After a careful revision of the safety evaluation report, the consensus for mining work shall be issued by the SNSA. After finishing the mining ...
TRACI, a model based on the physical mechanisms governing the radon transport in unsaturated soils, has been developed to evaluate the radon flux density at Uranium Mill Tailings (UMT) covers surface. First, moisture contents in the soil, induced by weather conditions, are calculated. Then, radon concentrations in the air-filled pore space, and radon flux density at the soil surface, are deduced from a transport model which takes account for diffusion and convection in the pore space. To check the hypothesis used in TRACI and the efficiency of cover layers, an in situ study was launched in 1997 with the French uranium mining company, COGEMA. It consists of continuous measurements of moisture contents, suctions, radon concentrations at various depths inside an UMT cover, and flux density at its surface. The first analysis made on in situ observations shows that radon concentrations and flux density, calculated with a steady-state diffusion model using monthly ...
We consider two-dimensional large N gauge theory with D adjoint scalars on a torus, which is obtained from a D+2 dimensional pure Yang-Mills theory on T^{D+2} with D small radii. The two dimensional model has various phases characterized by the holonomy of the gauge field around non-contractible cycles of the 2-torus. We determine the phase boundaries and derive the order of the phase transitions using a method developed in an earlier work (hep-th/0910.4526), which is nonperturbative in the 'tHooft coupling and uses a 1/D expansion. We embed our phase diagram in the more extensive phase structure of the D+2 dimensional Yang-Mills theory and match with the picture of a cascade of phase transitions found earlier in lattice calculations (hep-lat/0710.0098). We also propose a dual gravity system based on a Scherk-Schwarz compactification of a D2 brane wrapped on a 3-torus and find a phase structure which is similar to the phase diagram found in the ...
In the present work the hydrogen desorption properties of nanostructured magnesium hydride (MgH2) synthesized by controlled reactive mechanical milling (CRMM) of elemental Mg powder under hydrogen are investigated. A profound effect of the particle size of synthesized MgH2 hydride on its hydrogen desorption characteristics measured by differential scanning calorimetery (DSC) has been found. All synthesized MgH2 powders are characterized by a double hydrogen desorption peak. Furthermore, below a certain threshold particle size the DSC desorption temperature of the peak doublet starts decreasing rapidly with decreasing of the mean hydride powder particle size (expressed as equivalent circle diameter-ECD). In contrast, the nanograin (crystallite) size of MgH2 does not seem to have apparent effect on the DSC desorption temperature. It is also observed that for powder particles smaller than some threshold value, X-ray diffraction shows the presence of two polymorphic ...
At tandem cold rolling mills in Kawasaki Steel, by means of applying newly developed strip longitudinal (rolling) and transverse gauge control systems, high accuracy of thickness of within {+-}0.5 % has been achieved over the full length and full width of cold rolled strip, as gauge accuracy in a coil in longitudinal and transverse directions has become an extremely important quality control item in the manufacturing of cold rolled sheets due to the stricter quality requirements of customers, in recent years. The longitudinal gauge accuracy has been improved by the development of a high-response drive system for a mill mair motor, an all-stands gauge control system and a dynamic set-up control system. The transverse gauge accuracy has been improved by applying a one-side tapered work roll shifting method and the development of an edge drop control system in terms of the optimum use of an edge drop sensor. (author)
Reactive milling of NiO + Al powder mixture resulted in the formation of NiAl-Al_2O_3 nanocomposite powders, with a crystallite size of about 20 nm. The Hall-Williamson analysis revealed that NiAl showed an orientation dependent crystallite size after short processing time and orientation dependent internal strain after long milling time. Both anisotropies were removed by heating the powders in the differential scanning calorimetry. Calorimetric studies showed one exothermic effect attributed to the reduction reaction of NiO and endothermic one associated with melting of Al. Two methods were applied for powders compaction: resistance sintering and pulse electric discharge. In both cases the densities of abut 90% of the theoretical value were achieved. A significant increase in average NiAl crystallites size in compacted samples was observed, up to several hundreds of nanometers.(author)
The possibility of oxidizing at a PbO{sub 2} anode the phenols and polyphenols, present in the olive oil mill wastewater, has been studied as a pre-treatment for the submission of such wastewater to the traditional biological treatments. The results obtained operating at current densities ranging 500 to 2000 A/m{sup 2} show that it is possible to reduce the concentration of the phenolic components, which interfere with the biological treatments, down to low values without decreasing too much the total organic content of the wastewater. [Italian] E' stata studiata la possibilita' di ossidare anodicamente i componenti fenolici delle acque reflue di frantoio, quale pretrattamento delle stesse prima del loro invio ai processi di trattamento biologico. I risultati ottenuti impiegando PbO{sub 2} quale materiale anodico e operando con densita' di corrente comprese tra 500 e 2000 A/m{sup 2} mostrano come sia possibile eliminare, o almeno ...
Both the increased complexity of integrated circuits, resulting in six or more levels of integration, and the increasing use of flip-chip packaging have driven the development of integrated circuit (IC) failure analysis tools that can be applied to the backside of the chip. Among these new approaches are focused ion beam (FIB) tools and processes for performing chip edits/repairs from the die backside. This paper describes the use of backside FIB for a failure analysis application rather than for chip repair. Specifically, they used FIB technology to prepare an IC for inspection of voided metal interconnects (lines) and vias. Conventional FIB milling was combined with a super-enhanced gas assisted milling process that uses XeF{sub 2} for rapid removal of large volumes of bulk silicon. This combined approach allowed removal of the TiW underlayer from a large number of Ml lines simultaneously, enabling rapid localization and plan view imaging of ...
Alloy 800 from three different commercial heats have been continuously cycled and cycled with a hold period at 922/sup 0/K. The starting microstructures of these heats reflects an inherently wide spectrum of possibilities for Alloy 800. The amounts and morphologies of the TiC and M/sub 23/C/sub 6/ carbides are different among the heats. During cycling, M/sub 23/C/sub 6/ forms intragranularly in a solution annealed heat. This precipitation contributes to the cyclic hardening. Both mill annealed heats of Alloy 800 are stable to carbide precipitation during cycling. The heat with the lower carbon content formed ..gamma..' during cycling but the volume fraction was too low to contribute to hardening. The inclusion of hold periods caused the dislocation substructure to become more diffuse in the mill annealed heats. The cyclic hardening was enhanced with the inclusion of the hold periods but this was not due to any microstructural change ...
In this letter we present a derivation, from the D0-brane picture, of the background monopole field and in general of the full dynamics of the Yang-Mills theory on the dielectric D2-brane of Myers. To do this we study the large N limit of the fuzzy sphere relevant to the dielectric solution. In contrast to the usual interpretation where the commutative D2-brane picture arises directly from the large N limit of the D0-brane picture, we find that a residual non-commutativity must be preserved in order to make the connection by means of the Seiberg-Witten map.
Defects ~10 nm in size, with number densities ~10^{10} cm^{-2}, form spontaneously beneath ion-milled, etched, or HF-dipped silicon surfaces examined in our Ti-ion getter-pumped transmission electron microscope (TEM) after exposure to air. They appear as weakly-strained non-crystalline intrusions into silicon bulk, that show up best in the TEM under conditions of strong edge or bend contrast. If ambient air exposure is <10 minutes, defect nucleation and growth can be monitored {\\em in situ}. Possible mechanisms of formation are discussed.
The rate at which full-scale technology transfer takes place depends on the quality of the supply companies, i.e. training, organisational development and product infrastructure. These parameters are discussed for the example of a water mill, and a flow diagram is presented. [Deutsch] Wie rasch ein umfassender Transfer in Frage kommt, entscheidet sich mit der Qualitaet und dem Niveau der zuliefernden Betriebe. Hierbei sind Ausbildung, Organisationsentwicklung und Produktionsinfrastruktur besonders angesprochen. Fuer eine Wassermuehle werden diese Parameter konkret eroertert und an Durchlaufdiagrammen erlaeutert. (GL)
The DOE`s clean-up of its nuclear complex require the development of innovative technologies to convert soils contaminated by hazardous and/or radioactive wastes to forms which can be readily disposed in accordance with current waste disposal methods. The unique features of Votec CMS technology should make it particularly cost-effective process for the vitrification of soils, sediments, sludges, and mill tailings containing organic metallic and/or radioactive contaminants. This article describes the technology (Votec`s combustion and melting system), the results of testing, the demonstration plant system, and summarizes the future schedule and the equipment needed. 3 figs., 3 tabs.
Lithium orthosilicate (Li_4SiO_4) powder was synthesized by the solid-state reaction of lithium oxide with amorphous silica, and the effects of fabrication parameters on the structural characteristics of the product were investigated. Processing considerations such as milling media, drying technique, calcination time and temperature, pressing behavior, sintering time and temperatures, and impurity concentration were addressed. The initial powder particle size was observed to be important in achieving high sintered density, with densities as high as 98% TD achieved with a particle size of approximately 1 #mu#m. 9 refs., 6 figs.
Radiological hazard in uranium mining and milling operations are primarily due to exposure to external beta and gamma radiation as well as to airborne radionuclides which consist of radon and its short-lived daughter products. In May 1981 a radiological survey programme was performed in order to make a general assessment of the radiation hazards associated with the uranium mines and the Uranium Pilot Plant operated by the M.T.A. Institute in the Koprubasi district of the Manisa province. In this paper a preliminary radiological risk evaluation attempt is presented based on the radiation and radioactivity measurements performed in this district in May 1981.
This paper reported on a study in which partial discharge (PD) measurements were performed on 6 underground transmission cable circuits to determine the effectiveness of PD measurements on fluid fill cables. The cables were between 37 and 56 years old. PD activity was detected from the terminations of H11L and H3L Cable 2. However, for cables from H3L Basin TS to Mill Street junction, PD activity was detected originating from within the main cable insulation.
Abstract in english Odontopus brevirostris (Hustache, 1936) feeding on Annona squamosa L., A. cherimola Mill., A. glabra L., and A. muricata L. was observed. The last three host plants are recorded for the first time. The endophitic oviposition occurs in the veins of the ventral surface of the young leaves. The larvae, leaf miners, eat the parenchyma and the adults make small holes in the leaves. The pupation occurs in spherical cocoons protected by a sort of nest (pupation chamber) between the two epidermal layers.
A study was conducted to examine the energy consumption in existing and new hog farming facilities and to analyse the potential for increased natural gas use in the Saskatchewan hog industry. Existing heating/cooling, ventilation and feed mill equipment choices offer possibilities for running on electricity, natural gas or propane. Energy costs are lowest when natural gas is used. To put the study in context, an overview of the Saskatchewan hog industry was provided. The potential increase in natural gas use in hog production by year 2005 was estimated. 10 refs., 6 tabs., 8 figs.
This monograph gives a detailed and pedagogical account of the geometry of rigid superspace and supersymmetric Yang-Mills theories. While the core of the text is concerned with the classical theory, the quantization and anomaly problem are briefly discussed following a comprehensive introduction to BRS differential algebras and their field theoretical applications. Among the treated topics are invariant forms and vector fields on superspace, the matrix-representation of the super-Poincare group, invariant connections on reductive homogeneous spaces and the supermetric approach. Various aspects of the subject are discussed for the first time in textbook and are consistently presented in a unified geometric formalism.
The petroleum sector is highly significant for the Norwegian economy. Its share of gross domestic product, exports and total government revenues has been substantial over the past two decades, reaching a particularly high level in 2000 and 2001. The principal reason why revenues were so high in these two years is a combination of high oil prices, a strong USD against the NOK and historically high petroleum production. The share of petroleum investment in total capital spending in the Norwegian economy was at its highest in the early 1990s. Total investment in the petroleum sector has been above NOK 40 bn every year since 1992, and peaked in 1998 at roughly NOK 80 bn. Capital spending declined to around NOK 56.9 bn in 2001. The government's most important revenue sources in recent years have been cash flow from the state's direct financial interest (SDFI) and from taxes. Production of crude oil has averaged around three mill barrels per day since ...
We consider a D-brane probe in the unstable string background associated with flux branes. The twist in the spacetime metric reponsible for supersymmetry breaking is shown to manifest itself in the mixing of open Wilson lines with the phases of some adjoint matter fields, resulting in a nonlocal and nonsupersymmetric form of Yang-Mills theory as the probe dynamics. This provides a setup where one can study the fate of a large class of unstable closed string theories that includes as a limit type 0 theories and various orbifolds of type II and type 0 theories. We discuss the limit of C/Z_n orbifold in some detail and speculate on the couplings with closed string tachyons.
Using near-field optical microscopy, the authors investigate propagation of channel plasmon polaritons excited in the wavelength range of 1425-1640 nm along smoothly bent and split V-shaped grooves milled in a gold film. We find that for 0.6-?m-wide and 1.1-?m-deep grooves bent with the smallest curvature radius of ?0.83 ?m, the double bend (for S bends) and splitting (for Y splitters) losses decrease for longer wavelengths approaching (in the wavelength range of 1600-1640 nm) the levels of ~0 and 0.5 dB, respectively.
The formation mechanism of the cold-rolled strip shape with high tension was studied. An advanced method to calculate the allowable variation of strip transverse profiles was established by the strip buckling criterion, which can be more properly used in cold rolling. With this method, the aim allowable variation of the product strip transverse profile and the required transverse profile range of incoming strips can be reached. Besides, this method has been successfully applied in a domestic tandem cold mill, and the transverse profile range of incoming strips suggested with this method is more practicable and complete. Consequently, the good performance is acquired.
The efficiency of NbC on WC grain coarsening in a WC-10wt.%Co hardmetal alloy was demonstrated by hardness measurement and WC granulation observation. The heterogeneous and overall grain growth were controlled. A low temperature experimentally produced NbC was used and compared to the inhibition potential of a commercial NbC powder. The results were the same in terms of structural fineness and hardness. The dispersion of the experimental NbC was not a problem, in spite of its size. The experimental NbC has very large particles, formed by agglomerates of small crystallites. During milling these agglomerates could be broken down. (orig.)
A survey is given on the results in hand on the natural radioactivity of building materials. It is shown that only a small percentage of building materials has an increased content of radioactive materials. The results are compared with approximate values given in a Russian publication. (orig./AK).
... Highly-Functional Materials" was launched in JFY1996 under the New Materials field. This project was ... Bio-mimetic materials" (1) Advanced stimuli responsive materials (2) Harmonized molecular materials ...
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... 1995 Trilateral Materials Workshop PDF (202K) Report of the Workshop on Materials for Future ... in Materials Research Technology and Education PDF (163K) US-Asian Pacific Materials Research ...
Once again Brazil faces the possibility of an electricity shortage in the near future. The low level of rain and the consequent reduction of hydroelectric reservoirs (hydroelectric energy represents almost 80% the total Brazilian electricity generation) led to the dispatch of thermal plants based on natural gas and/or fuel oil. However, the recent crisis regarding the Bolivian natural gas supply to Brazil increased the risk of a shortage of this energy source. Hence, the uncertainty of the electricity supply scenario is pushing the electricity prices up in the near future. A possible alternative to increase the electricity supply is the maximization of the electricity surplus in sugarcane mills. Back in 1970's and 1980's, cogeneration plants in sugarcane mills were primarily designed to consume all bagasse, and produce steam and electricity to the process. The plants used medium pressure steam boilers (21 bar and 300 deg C) ...
In the present paper a procedure is proposed for the determination of traces of Cd, Co, Mn and Cr in petroleum industry produced water by inductively coupled plasma optical emission spectrometry. The procedure is based on cloud point extraction of these metals, as their dithizonate complexes, into the surfactant-rich phase of octylphenoxypolyethoxyethanol surfactant (Triton X-114). Extractions were carried out in solutions with salinities between 10 per mille and 70 per mille. Since residual salinity in the surfactant-rich phase caused differences in its transport to the plasma, yttrium was used as an internal standard to correct for this effect. The simultaneous metal extraction procedure was optimized by response surface methodology using a Doehlert design and desirability function. Enhancement factors of 21, 21, 9 and 19, along with limits of quantification of 0.093, 0.20, 0.73 and 1.2 #mu#g L"-"1, and precision expressed as relative ...
This project, conducted under The United States Department of Energy (DOE) Cooperative Agreement DE-FC36-94GO10002/A002, was part of a multiple-phase effort to develop technologies that improve the energy efficiency and economics of chemical process recovery in the pulp and paper industry. The approach taken was to consider two major alternatives in two phases. Phase I, conducted previously, considered means to improve pulp mill recovery boilers using high-solids advanced combustion of black liquor; while this project, Phase la, considered means to recover kraft pulping mill process chemicals by low-temperature black liquor gasification. The principal steps previously proposed in this program were: (1) Evaluate these two technologies, high-solids advanced combustion and gasification, and then select a path forward using the more promising of these two options for future work. (2) Design and construct a pilot-scale unit based on the selected ...
Computation of effective flow properties of fluids in porous media based on three dimensional (3D) pore structure information has become more successful in the last few years, due to both improvements in the input data and the network models. Computed X-ray microtomography has been successful in 3D pore imaging at micron scale, which is adequate for many sandstones. For other rocks of economic interest, such as chalk and diatomite, submicron resolution is needed in order to resolve the 3D-pore structure. To achieve submicron resolution, a new method of sample serial sectioning and imaging using Focused Ion Beam (FIB) technology has been developed and 3D pore images of the pore system for diatomite and chalk have been obtained. FIB was used in the milling of layers as wide as 50 micrometers and as thin as 100 nanometers by sputtering of atoms from the sample surface. The focused ion beam, consisting of gallium ions (Ga+) accelerated by potentials of up to 30 kV and ...
In this work, a focused ion beam (FIB) milling process has been developed to fabricate 50 nm Bi nanowire and transistor structures using FEI-200 dual beam FIB system. For the fabrication, 50 nm bismuth film was thermally evaporated through EBL patterned PMMA windows onto SiO_2 substrates with pre-defined contact pads. Bi nanowire widths ranging from 30 nm to 100 nm have been successfully fabricated by milling out unwanted areas using 30 KeV Ga+ ion beam. A single-pixel-line ion beam blanking technique has been utilised to fabricate Bi nanowire as small as 30 nm in diameter and few micrometers long. In order to form good ohmic contacts for sub 50 nm bismuth nanowires, a drill-and-fill process has been developed using FIB to sputter away the surface oxide of bismuth after the in-situ platinum nanowire contacts deposition. To our knowledge, this is the first time a focused ion beam process has been used to fabricate bismuth nanowire. The ...
Energy use patterns and utilisation efficiencies in 40 factories producing palm kernel oil (PKO) in southwestern part of Nigeria were studied. The factories were stratified into small, medium and large scale categories based on the mode of operations and production capacities. Questionnaires were administered on the factories to obtain historical data on petrol, diesel and electricity consumption and PKO production outputs for seven years (1998-2004). Energy use efficiency indicators employed include: energy intensity (EI), energy cost per unit product (EC/P), energy ratio (ER), food energy ratio (FER) and percentage oil yield by weight. Results of the study indicated that averagely, 0.58, 0.53 and 0.74 GJ/10{sup 3} l of PKO were needed in the small, medium and large PKO factories, respectively. The average food energy ratios in the small, medium and large mills are 2.48, 2.53 and 2.14, respectively. The corresponding values of PKO conversion ratio are 0.43, 0.50 ...
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As adulterated and substituted Chinese medicinal materials are common in the market, therapeutic effectiveness of such materials cannot be guaranteed. Identification at species-, strain- and locality-levels,...Full Text Available
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Improvements to a small diesel engine turbocharger were made based on data gathered during a previous Army contract. The improved turbocharger was fabricated and tested on a small, four cylinder, 239 CID diesel engine. Engine dynamometer test data revealed a 2 to 9 percent reduction in fuel consumption at all points over the operating envelope. A turbocharger was operated for 1011 hours at speeds between 70000 and 78000 rpm without incident. The ball bearings were in excellent condition at the end of the test. A math model of the engine and turbocharger was generated. The model was used to estimate 13 Mode Federal Diesel Emissions Cycle, the LA4 driving cycle and the application of the variable area turbine nozzle (VATN) turbocharger to a diesel engine driven generator set. A recommendation was made to build a gen set demo unit. A fuel savings of 8 to 10 percent was estimated for a 30KW DED generator set.
Carbothermal reduction-nitridation (CRN) of SiO_2 is an attractive method for manufacturing Si_3N_4 powders with controlled grain morphology. Moreover, #beta#-sialon powders could also be synthesized from either pure powder mixtures or some inexpensive raw minerals by CRN. The resultant powders have shown some advantages, especially in manufacturing sialon products at low cost. However, there have been only a few works on preparing #alpha#-sialon powders. In this work, Ca-#alpha# sialon powder was synthesized by CRN of a SiO_2-Al_2O_3 and CaCO_3 powder mixture An unusual morphology of hollow balls of 200 to 500nm with many nano size #alpha#-sialon particles of 10 to 30nm was identified from the resultant Ca-#alpha# sialon powders. This has never been previously reported for sialon ceramics. It was consequently confirmed that the morphologies of the products were clearly related to the intermediate products appearing during CRN reaction. Copyright (2000) The ...
Helically coiled tubes of steam generators (SG) in FBR are boundaries between sodium and water/steam. Therefore, to assure the integrity of tubes, it is necessary to inspect the tubes nondestructively for in service or after a sodium-water reaction accident. In order to make it possible to conduct in-service inspection of SG tubes, we have studied on eddy current probes and probe inserting methods. As for the probe inserting method, IHI designed a fluid driving type which consists of a model probe and signal cable with float balls and driven by air pressure force. Presented in this paper is the authors' report, which describes the fluid driving type as an effective method to insert an eddy current probe into helically coiled tubes. The outline of the test results is as follows: 1. It was possible to insert the probe into 65 meter length helically coiled tubes. 2. We could detected, as anticipated, a defect (outer circumferential wall thinning defect, 20% depth) on ...
One aspect of the research program SFB 570 'Distortion engineering' is the in situ X-Ray diffraction analysis of phases and residual stresses during complete heat treatment cycles. These investigations result in experimental evidence available for the extensive computations. The optimisation of the instrumentation will be reported. A surface decarburisation of samples made from the ball bearing steel 100Cr6 could be avoided for a temperature range from 800 to 900 C and a holding time of one hour by a combination of evacuate the furnace and using a certain nitrogen flow as protective gas. At lower temperatures small amounts of ferrite caused by an increased diffusion rate of carbon lead again to a surface decarburisation up to a depth of 2 {mu}m. It was proved that with an evacuation of the X-Ray beam path at constant power of the X-Ray source the intensity of diffraction lines could be increased by more than a factor of 4. The use of nitrogen as ...
Radiation damage studies have been carried out on undoped and CrO_4"2"- doped potassium and ammonium alums. The optical absorption bands observed around 27100 and 36500 cm"-"1 before irradiation have been attributed to the transitions t_1 #-># e and t_1 #-># t_2, on the basis of Ball-hausen and Liehr scheme. On prolonged X-irradiation, these bands disappear in both the alums and three new bands seem to grow in ammonium alum while only two new bands could be seen in potassium alum. EPR studies at RT reveal that there are two lines at g = 2.004 and g = 2.010 in ammonium alum and only one line at g = 2.004 in potassium alum. Besides these two nearly isotropic lines, there is a set of lines around g = 1.95 in both the alums. Correlating the optical and EPR studies it is concluded that SO_3"- and O_3"- centres have formed on X-irradiation in ammonium alum while only SO_3"- seems to have formed in potassium alum. The most important feature is the formation of a new ...
Duplex-coating procedures consisting of plasma nitriding and Me-C:H hard coating lead to an improved performance of the devices because the Me-C:H coating is supported by the nitrided phase and, therefore, the `eggshell-effect` is avoided. Furthermore, this support leads to a higher load-bearing capacity of the thin film. Two standard procedures (classical high-pressure plasma nitriding and unbalanced magnetron sputtering of Ti-C:H) were performed subsequently to prepare the duplex coatings on X20Cr13 ferritic stainless steel. The corrosion resistance of the steel could be improved by nitriding at 450 C compared to the untreated ferritic substrate. The roughness is determined by the nitriding step. The weakest point of the coating is the transition zone between the nitrided and the untreated substrate and not the interface between the Ti-C:H coating and the nitrided substrate as shown by the Rockwell and scratch tests. The adhesion of the duplex structure (plasma nitriding and Ti-C:H ...
The densification of #alpha#"1-and #alpha#"+#beta#"1-sialon ceramics has been studied by means of in situ dilatometry. It is seen that the densification is greatly affected by the reaction sequences and the grain growth. The formation and densification of sialons start simultaneously as the dissolution of nitrides into the oxide eutectic liquid phase occurs. The formation of sialons is complete at 1800 deg C., while full densification can only be obtained by using gas pressure sintering. The typical microstructure of both #alpha#"'-and mixed #alpha#'+#beta#'-sialon ceramics consists of a crystalline phase of sialons and a small fraction of amorphous phase at grain boundaries. Vickers hardness (HV0.5) was measured by using the indentation technique, and the biaxial bending strength (#sigma#_b_i) was determined with the 'ball-on-ring' test. Fracture toughness was determined by using both the indentation and single-edged notched beam techniques. It is concluded that ...
High spin states of the proton rich nuclei in the mass region A {approx} 100 have been studied at the GASP spectrometer through the evaporation of light charged particles and heavier ions detected in the 4{pi} Si-ball Isis. Rear side injection and pulse shape analysis have allowed a good discrimination among protons, alpha particles and heavy ions up to C. Of the several nuclei populated in the reactions we will discuss here the high spin states of {sup 105} Sn. In addition to an extension of the spherical level, scheme, a regular sequence of dipole transitions has been found, The states of the dipole band are suggested to be built on a neutron h{sup 2}{sub 11/2} excitation coupled to proton particle-hole states, which polarize the core to a slightly prolate shape. The experimental results are in agreement with the prediction of tilted axis cranking calculations, which satisfactorily explain the properties of the band. (author) 17 refs., 4 figs.
Let A and B be two affinely generating sets of (Z_2)^n. As usual, we denote their Minkowski sum by A+B. How small can A+B be, given the cardinalities of A and B? We give a fairly tight answer to this question. Our bound is attained when both A and B are unions of cosets of a certain subgroup of (Z_2)^n. These cosets are arranged as Hamming balls, the smaller of which has radius 1. By similar methods, we reprove the Freiman-Ruzsa theorem in (Z_2)^n, with an optimal upper bound. Denote by F(K) the maximal spanning constant || / |A|, over all subsets A of (Z_2)^n with doubling constant |A+A| / |A| < K. We explicitly calculate F(K), and in particular show that 4^K / 4K < F(K) (1+o(1)) < 4^K / 2K. This improves the estimate F(K) = poly(K) 4^K, found recently by Green and Tao and by Konyagin.
Objective: Traditional nasolacrimal duct stenting possesses some shortcoming including difficulty of pulling ball head guide wire from the nasal cavity with turbinate hypertrophy and nasal septal deviation. The new method of nose-oral tube track establishment can overcome the forementioned and increase the successful rate. Methods: 5 F catheter and arterial sheath were modified to be nasolacrimal duct stent delivery device respectively. Antegrade dacryocystography was taken firstly to display the obstructed site and followed by the modified protocol of inserting the guide wire through nasolacrimal duct and nasal cavity, and establishing the stent delivery track for retrograde stent placement. Results: 5 epiphora patients with failure implantation by traditional method were all succeeded through the modified stenting (100%). During 6-mouth follow-up, no serious complications and reocclusion occurred. Conclusion: The establishment of eye-nose-mouth-nose of external ...
A centrifugal pump was developed for the efficient and reliable transfer of liquid helium in space. The pump can be used to refill cryostats on orbiting satellites which use liquid helium for refrigeration at extremely low temperatures. The pump meets the head and flow requirements of on-orbit helium transfer: a flow rate of 800 L/hr at a head of 128 J/kg. The overall pump efficiency at the design point is 0.45. The design head and flow requirements are met with zero net positive suction head, which is the condition in an orbiting helium supply Dewar. The mass transfer efficiency calculated for a space transfer operation is 0.99. Steel ball bearings are used with gas fiber-reinforced teflon retainers to provide solid lubrication. These bearings have demonstrated the longest life in liquid helium endurance tests under simulated pumping conditions. Technology developed in the project also has application for liquid helium circulation in terrestrial facilities and for ...
The Cahn-Hilliard-Navier-Stokes system is based on a well-known diffuse interface model and describes the evolution of an incompressible isothermal mixture of binary fluids. A nonlocal variant consists of the Navier-Stokes equations suitably coupled with a nonlocal Cahn-Hilliard equation. The authors, jointly with P. Colli, have already proven the existence of a global weak solution to a nonlocal Cahn-Hilliard-Navier-Stokes system subject to no-slip and no-flux boundary conditions. Uniqueness is still an open issue even in dimension two. However, in this case, the energy identity holds. This property is exploited here to define, following J.M. Ball's approach, a generalized semiflow which has a global attractor. Through a similar argument, we can also show the existence of a (connected) global attractor for the convective nonlocal Cahn-Hilliard equation with a given velocity field, even in dimension three. Finally, we demonstrate that any weak solution fulfilling ...
In the utilization of the thermal energy by ocean temperature difference and factory waste heat, the high performance heating surfaces in pipes from which scale can be removed are required. As the method of removing scale, the method using sponge balls seems most suitable, but for applying this method, as the form of the protrusions attached to the inner surfaces of pipes, smooth circular are form is desirable. The promotion of heat transfer with the rows of circular arc protrusions like this is strongly related to the mode of flow and such structure as separation, recirculation flow, readhesion and turbulent energy generation. In this study, as the basic research to optimize the heating surface with the rows of smooth protrusions, the flow characteristics and the heat transfer characteristics including the turbulent structure of the wake of protrusions were experimentally determined, and the essence of the heat transfer characteristics was to be clarified on the ...
A duplex surface treatment technique based on calorizing and plasma nitriding was developed to improve the wear and oxidation resistance of H13 steel at high temperatures. The effects of the relative thickness of the calorized layer to the depth of plasma nitriding on the wear and oxidation properties at temperatures up to 900 C were investigated in this work. High-temperature wear tests were performed at 500 C with dry conditions in open air using a ball-on-disk type tribotest machine. Isothermal oxidation tests were performed at 900 C for up to 100 h under controlled atmosphere. The results indicated that the specimens with a calorized layer as an intermediate phase between the surface duplex layer and the base metal showed higher wear and oxidation resistance than the specimens with a nitrided layer alone. During exposure to elevated temperatures, the aluminum in the calorized layer diffused to the surface and formed an aluminum oxide layer. This oxide layer ...
High-spin states of "1"8"7Ir have been populated in the "1"7"6Yb("1"5N,4n) reaction and measured with the YRAST Ball spectrometer. The #pi#h _9_/_2 rotational band has been extended beyond the first alignment crossing, which was found at rotational frequency (#Planck constant#/2#pi#)#omega# _c #approx =#0.39 MeV . Two different scenarios for describing this crossing are considered: the alignment of an h _9_/_2 proton or i _1_3_/_2 neutron pair and it is concluded that a proton band crossing is more likely. A systematic study of the rotational alignment crossings in the #pi#h _9_/_2 bands in the N=104,106,108 isotopes of _7_3Ta,_7_5Re,_7_7Ir, and _7_9Au is presented.
In this paper, for a given sequentially Yoneda-complete T_1 quasi-metric space (X,d), the domain theoretic models of the hyperspace K_0(X) of nonempty compact subsets of (X,d) are studied. To this end, the $\\omega$-Plotkin domain of the space of formal balls BX, denoted by CBX is considered. This domain is given as the chain completion of the set of all finite subsets of BX with respect to the Egli-Milner relation. Further, a map $\\phi:K_0(X)\\rightarrow CBX$ is established and proved that it is an embedding whenever K_0(X) is equipped with the Vietoris topology and respectively CBX with the Scott topology. Moreover, if any compact subset of (X,d) is d^{-1}-precompact, \\phi is an embedding with respect to the topology of Hausdorff quasi-metric H_d on K_0(X). Therefore, it is concluded that (CBX,\\sqsubseteq,\\phi) is an $\\omega$-computational model for the hyperspace K_0(X) endowed with the Vietoris and respectively the Hausdorff topology. Next, an algebraic ...
Objective: To compare the efficiency of dual energy subtraction and conventional direct digital radiography in signal detecting ability. Methods: 200 plastic balls which were 4 mm in diameter were taken as signals and were placed on a 10 cm thick plastic board and the right upper thorax of a healthy volunteer. The signals were examined by DES and CDR separately and were estimated by 3 radiologists with 5-value-differentiation method. ROC curve analysis was made by ROC kit software. Results: when signals on plastic board were detected by CDR and DES, ROC curve analysis indicated that there was no significant difference (P=0.4851 > 0.05, two-tailed) between the area under the ROC curves of the two methods (Az=0.9931 for CDR and Az=0.9879 for DES). The difference was significant (P=0.0002 <0.01, two-tailed) between the area under the ROC curves of CDR and DES (Az=0.7276 for CDR and Az=0.8561 for DES), when the signals on the right upper thorax of a volunteer ...
The Loose Parts Monitoring System (LPMS) provides information on the location of a loosened or detached metal impacted onto the inner surface of a primary pressure boundary and on a mass or energy of the impact signal. For the conventional system, it is popular to employ the group delay among the sensors installed within 3 ft range from the impact source in a collection zone as stated in the Reg. Guide 1.133. However, there exist inherent errors for the estimation of the true location of the impact since it is highly dependent on the plant personnel's decision to determine the arrival time differences of the generated wave group among the neighbouring sensors. To overcome this problem in this study, the two-dimensional approach has been proposed and applied to effectively estimate the arrival time differences of the impact signal by using continuous wavelet transform which is one of the linear time-frequency analysis methods. The experiment has been implemented on the plate model and ...
1. Contest rules The European Space Agency (ESA) is launching a public competition to find the most suitable names for its four Cluster II space weather satellites. The quartet, which are currently known as flight models 5, 6, 7 and 8, are scheduled for launch from Baikonur Space Centre in Kazakhstan in June and July 2000. Professor Roger Bonnet, ESA Director of Science Programme, announced the competition for the first time to the European Delegations on the occasion of the Science Programme Committee (SPC) meeting held in Paris on 21-22 February 2000. The competition is open to people of all the ESA member states (*). Each entry should include a set of FOUR names (places, people, or things from history, mythology, or fiction, but NOT living persons). Contestants should also describe in a few sentences why their chosen names would be appropriate for the four Cluster II satellites. The winners will be those which are considered most suitable and relevant for the Cluster II mission. ...
... Tokyo Report: Japanese Government Budget for Materials R&D Date: 6/17/97 The National Science ... Graded Materials Area coordinator: Dr. Toshio Hirai, Professor, Institute for Materials Research ...
... impact criterion, as demonstrated by the materials research community. These include training ... designing new materials or new processing/fabrication routes to existing materials; exploring and ...
... of new construction materials; and the behavior of infrastructure materials and structural ... polymers, reinforcing materials, wood and biodegradable structural materials; scale effects from ...
... The Effect of the Temperature to Which the Material is Heated on the Process of Formation of Intermetallic Compounds in Magnetic Pulse Welding,. ...
... and Security..........................13 Materials Science ... hybrid system theory, Internet analysis, materials science, mixing, physiology, iterative control ...
... many intriguing new possibilities in the materials sciences. Or consider solitons, a mathematical ... point out that advanced instrumentation, new materials, novel production methods, and efficient ...
This study evaluated woody biomass from logging residues, small-diameter trees, mill residues, and urban waste as a feedstock for cellulosic ethanol conversion in Mississippi. The focus on Mississippi was to assess in-state regional variations and provide specific information of biomass estimates for those facilities interested in locating in Mississippi. Supply and cost of four woody biomass sources were derived from Forest Inventory Analysis (FIA) information, a recent forest inventory conducted by the Mississippi Institute for Forest Inventory, and primary production costs. According to our analysis, about 4.0 million dry tons of woody biomass are available for production of up to 1.2 billion liters of ethanol each year in Mississippi. The feedstock consists of 69% logging residues, 21%...
The current status and prospects for Japan`s economy and steel industry, forecast for demand and supply of coking coal, directions in steel making technology, and Japan`s expectations for Canadian coal are discussed. The PCI system, the Coal Moisture Control System (CMC) to increase coke density before it is fed into coke ovens, a feeder that allows use of lower quality coke on the outskirts of blast furnaces, the Direct Iron Ore Smelting (DIOS) Process, and the `Next Generation Coke Oven`, where coke is heated rapidly and coked at 700-800{degree}C are considered. By 2000, semi-soft coking coals are expected to account for over half of total coal consumption by Japanese steel mills.
Among the several chemical processes conducted for the removal of organic matter present in wastewaters coming from some agro-industrial plants (wine distilleries, olive oil mills, etc), the oxidation by ozone has shown a great effectiveness in the destruction of specially refractory pollutants: it is demonstrated that the biodegradability of those wastewaters increases aflcer an ozonation pretreatment. Their great pollutant character is imputed to the presence of some organic compounds, like phenols and polyphenols, which are toxic and inhibit the latter biological treatments. In this research, a competitive kinetic procedure reported by Clurol and Nekouinaini is applied to determine the degradation rate constants by ozone of several phenolic acids which are present in the wastewaters from the olive oil obtaining process. The resulting kinetic expressions for the ozonation reactions are useful for the successful design and operation of ozone reactors in water and ...
Bioethanol (fuel alcohol) has been produced by industrial alcoholic fermentation processes in Brazil since the beginning of the twentieth century. Currently, 432 mills and distilleries crush about 625 million tons of sugarcane per crop, producing about 27 billion liters of ethanol and 38.7 million tons of sugar. The production of bioethanol from sugarcane represents a major large-scale technology capable of producing biofuel efficiently and economically, providing viable substitutes to gasoline. The combination of immobilization of CO2 by sugarcane crops by photosynthesis into biomass together with alcoholic fermentation of this biomass has allowed production of a clean and high-quality liquid fuel that contains 93% of the original energy found in sugar. Over the last 30?years, several inn...
Soil placed over any sealant/barrier system can provide a protective mantle if the soil is not lost by erosion. Vegetation is an attractive choice for controlling erosion because it can provide an economic self-renewing cover that serves to reduce erosion by both wind and water. Vegetation alone, however, may not adequately stabilize the surface in extremely arid areas. In those areas, a properly designed surface treatment of rock cover, perhaps in conjunction with vegetation, may be necessary to stabilize the tailings surfaces. The objective of this program is to establish guidelines for surface stabilization that are compatible with sealant/barrier systems and that are suited to soils and climates at inactive uranium mill tailings sites. These guidelines will provide the means to estimate potential vegetation cover, potential erosion, effects of surface treatments on sealant/barrier systems, and costs of vegetation and rock covers. Methods for establishing ...
Lisy ME, Jarvis KB, DelBello MP, Mills NP, Weber WA, Fleck D, Strakowski SM, Adler CM. Progressive neurostructural changes in adolescent and adult patients with bipolar disorder.-Bipolar Disord 2011: 13: 396-405. 2011 The Authors.-Journal compilation 2011 John Wiley & Sons A/S. Objectives:- Several lines of evidence suggest that bipolar disorder is associated with progressive changes in gray matter volume (GMV), particularly in brain structures involved in emotional regulation and expression. The majority of these studies however, have been cross-sectional in nature. In this study we compared baseline and follow-up scans in groups of bipolar disorder and healthy subjects. We hypothesized bipolar disorder subjects would demonstrate significant GMV changes over time. Methods:- A total of 58 ...
Recent Kawasaki Steel's development on size and shape measurement techniques for hot steel rolling processes is reviewed. First, a precision enhancement technique for a laser distance meter is described, then its rugged structure necessary for measurement in such tough environment as hot rolling processes is described in detail. A plate length meters and an inter-stand sensors for a hot strip mill are shown as developed size measurement techniques. Furthermore, plate shape meters and laser profile gauges for H-beams are depicted as specific examples of shape measurement techniques. (author)
We propose an extension of the su(2,2|4) superalgebra to incorporate the F1/D1 string charges in type IIB string theory on the AdS_5 X S^5 background, or the electro-magnetic charges in the dual super Yang-Mills theory. With the charges introduced, the superalgebra inevitably undergoes a noncentral extension, as noted recently in [1]. After developing a group theoretical method of obtaining the noncentral extension, we show that the charges form a certain nonunitary representation of the original unextended superalgebra, subject to some constraints. We solve the constraints completely and show that, apart from the su(2,2|4) generators, there exist 899 complex brane charges in the extended algebra. Explicitly we present all the super-commutators among them.
The methods of superconducting device fabrication by lithography and multilevel processing usually require a number of processing steps with lithographic resolution and alignment adequate for the scale of the device be fabricated. As an alternative, the focused ion beam (FIB) microscope is increasingly being used directly to fabricate devices. A major advantage of using a FIB compared to other lithography methods is its flexibility and high resolution. It allows in-situ, milling (#propor to#5 nm at a beam current of 1 pA) to a variety of depths, and imaging (2 nm) of the sample. In this paper we describe our development of junction fabrication techniques using the FIB and their application in creating a range of potential sensor devices and quantum electronics applications. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
In these lecture notes we derive a generic holographic string theory realization of a p-wave superconductor and superfluid. For this purpose we also review basic D-brane physics, gauge/gravity methods at finite temperature, key concepts of superconductivity and recent progress in distinct realizations of holographic superconductors and superfluids. Then we focus on a D3/D7-brane construction yielding a superconducting or superfluid vector-condensate. The corresponding gauge theory is 3+1-dimensional N=2 supersymmetric Yang-Mills theory with SU(N) color and SU(2) flavor symmetry. It shows a second order phase transition to a phase in which a U(1) subgroup of the SU(2) symmetry is spontaneously broken and typical superconductivity signatures emerge, such as a conductivity (pseudo-)gap and the Meissner-Ochsenfeld effect. Condensates of this nature are comparable to those recently found experimentally in p-wave superconductors such as a ruthenate compound. A string ...
The rational use of energy has become a priority for all industries in Brazil, mainly after the energy rationing in 2001. Methodologies to quantify and improve the performance of plants that consume and generate electricity and thermal energy are being used to reach this goal. Exergoeconomic analysis provides a complete diagnosis of a plant, both in exergetic and in monetary values. This study shows the methodology used to assess the power generation system of the Companhia Siderurgica Tubarao (CST). The current system is based on a regenerative Rankine cycle using two gases from steel production - blast furnace gas (BFG) and coke oven gas (COG) - to generate electric power and occasionally steam for the process. Use of the Theory of Exergetic Cost allowed determination of monetary and exe...
Energy use patterns and utilisation efficiencies in 40 factories producing palm kernel oil (PKO) in southwestern part of Nigeria were studied. The factories were stratified into small, medium and large scale categories based on the mode of operations and production capacities. Questionnaires were administered on the factories to obtain historical data on petrol, diesel and electricity consumption and PKO production outputs for seven years (1998-2004). Energy use efficiency indicators employed include: energy intensity (EI), energy cost per unit product (EC/P), energy ratio (ER), food energy ratio (FER) and percentage oil yield by weight. Results of the study indicated that averagely, 0.58, 0.53 and 0.74GJ/103l of PKO were needed in the small, medium and large PKO factories, respectively. T...
Ionizing radiation has been used to treat poultry to remove harmful microorganisms, mainly Salmonella, which contaminates chicken, goose and other fresh and frozen poultry. This microorganism is sensitive to low dose radiation. Thus, irradiating these foods with doses between 1 to 7 kGy results in a large reduction of bacteria. Since it is necessary to determine whether irradiation has occurred and to what extend, this work studied the signal produced by ionizing radiation within the hard crystalline matrix of chicken`s bone to establish a control method. Chicken`s drumsticks were irradiated and bones separated from flesh were lyophilized and milled. ESR spectrum was then obtained. The ESR signal increased linearly with dose over the range 0.25 to 8.0 kGy. Free radicals evaluated during 30 days after irradiation showed stable in this period. (Author).
The main sources of energy that might be available in remote low populated areas of Libya are either diesel generating units or wind mills for water pumping. Several problems in the working performance of these two types of energy production may arise due to environmental conditions. Direct conversion of solar energy can replace other ways of energy delivery or production, especially in this country where the solar radiation all year is relatively high. Direct conversion of solar energy is relatively expensive, however the cost of erecting long feeders and supervising them may be much more expensive than the usage of solar systems. This paper investigates the economics associated with either solutions of energy production. A case study is given in detail to supply one of the remote areas with a population of about 250. (author)
Kawasaki Steel started the construction of an automatic steel strip coil transportation system in the 1980's. Presently, most of the in-plant transportation of hot-rolled or cold-rolled coils are automated. For establishing the automatic transportation, there were developed various technologies, such as, the optimum handling technology using artificial intelligence, the technology of preventing additional piling of coils on existing coils by using an ultrasonic wave and a laser beam. Through the improvements of these technologies, a full-automated transportation system has been achieved and the system has contributed substantially toward product quality assurance and cost reduction. This paper gives the changes in the automation technology of coil transportation in the automation of No. 3 finishing hot rolling mill, now having the latest automatic system, in Chiba Works. (author)
A number of aerobic species capable of decolorizing some of the dyes in a textile mill effluent were isolated. One of the isolates was able to decolorize Terasil black dye under aerobic conditions in the presence of an exogenous carbon source after 5 days. Glucose or starch (%1 ea) are essential for decolorization but the process proceeds faster in the presence of 0.5% yeast extract. Results of the BOD5 show that the untreated effluent samples have a low BOD value, whereas treated samples show an initial increase in BOD up to 15 days followed by a decrease after 20 days. FT-IR and GC-MS data also reveal that the initial components in the untreated effluent disappear after 20 days of treatment, confirming biodegradation of the dye. Phytotoxicity tests on the untreated effluent samples using...
Experiments based on a 23 central composite full factorial design were carried out in 200-ml stainless-steel containers to study the pretreatment, with dilute sulfuric acid, of a sugarcane bagasse sample obtained from a local sugar?alcohol mill. The independent variables selected for study were temperature, varied from 112.5?C to 157.5?C, residence time, varied from 5.0 to 35.0 min, and sulfuric acid concentration, varied from 0.0% to 3.0% (w/v). Bagasse loading of 15% (w/w) was used in all experiments. Statistical analysis of the experimental results showed that all three independent variables significantly influenced the response variables, namely the bagasse solubilization, efficiency of xylose recovery in the hemicellulosic hydrolysate, efficiency of cellulose enzymatic saccharificatio...
A method using a focused ion beam (FIB) to prepare a silicon amorphous material is presented. The method involves the redeposition of sputtered material generated during the interaction of the Ga{sup +} ion beam with a silicon substrate material. The shape and dimensions of this amorphous material are self-organized and reproducible. The stability of this amorphous material under electron irradiation was investigated in the transmission electron microscopy (TEM). Electron irradiation can induce recrystallization of the amorphous material, resulting in the lateral and vertical growth, starting at an amorphous-crystalline interface, of polysilicon containing defects.
A method using a focused ion beam (FIB) to prepare a silicon amorphous material is presented. The method involves the redeposition of sputtered material generated during the interaction of the Ga"+ ion beam with a silicon substrate material. The shape and dimensions of this amorphous material are self-organized and reproducible. The stability of this amorphous material under electron irradiation was investigated in the transmission electron microscopy (TEM). Electron irradiation can induce recrystallization of the amorphous material, resulting in the lateral and vertical growth, starting at an amorphous-crystalline interface, of polysilicon containing defects.
Severe depletion of nutrients through removal of the above ground litter caused a cessation of growth of a Eucalyptus exserta forest in tropical China. Since there is no above ground input of C in this forest, microbial biomass (C_m_i_c) and soil organic C (C_o_r_g) are maintained by the below ground input only. By determining the maintenance requirement of the soil microflora, it should be possible to estimate the below ground production of this forest. To check this hypothesis the authors performed an experiment with labelled C. Since large scale production and field application of "1"4C labelled Eucalyptus litter were not feasible, 'naturally labelled' C_4 plant litter (Zea mays) was used. Maize litter has a #delta#"1"3C of -12.7 per mille as compared with a #delta#"1"3C of -30.7 per mille for Eucalyptus leaf litter. The "1"3C abundance is used to determine the amount of maize C in each of the soil layers. Investigations were made of how ...
A study tour in autumn 1999, which was undertaken following the award of the Helmuth Burkhardt prize of Wirtschaftsvereinigung Bergbau e.V. to the authors, comprised visits to potash, molybdenum, lead, zinc, copper ore and coal mines in the mid-west of the USA. The Black Mesa Mine and Kayenta Mine of Peabody Western Coal Company in the Navajo Reserve in the north of Arizona, the Trapper Mine Inc. near Craig and the Twentymile Coal Company near Steamboat Springs, Colorado are described in this report. In addition to a brief description of the geology the coal winning is considered in greater detail. The Twentymile Coal Company was asked to explain the reasons for the successful operation of the colliery, which produces more than 5 mill. t anthracite per year by long wall working. (orig.) [German] Eine Exkursion im Herbst 1999, die durch die Verleihung des Helmuth-Burkhard-Preises der Wirtschaftsvereinigung Bergbau e.V. an Bergassessor Andreas Tschauder zustande kam, ...
A cryogenic separation method of chloromethane (CH{sub 3}Cl) from methyl iodide (CH{sub 3}I) for {delta}{sup 37}Cl measurement with isotope ratio mass spectrometer is described. A cold trap with sealed 2,2,4-trimethylpentane (TMP) as the cryogen is used in this method. CH{sub 3}Cl can be separated from CH{sub 3}I at the TMP melting point (-107 deg. C) based on the difference in the vapor pressure between CH{sub 3}Cl (322.6 Pa) and CH{sub 3}I (lower than 1.3 Pa) at -107 deg. C. After two-step separation processes, the yields of CH{sub 3}Cl purified from CH{sub 3}Cl-CH{sub 3}I mixture are 96-101%, and the difference between the {delta}{sup 37}Cl{sub original} and {delta}{sup 37}Cl{sub Afterseparation} is from -0.06 to +0.06 per mille (0.01 {+-} 0.04 per mille ). These results suggest that CH{sub 3}Cl is completely separated from CH{sub 3}I with no change of {delta}{sup 37}Cl value. This method using the cold trap with sealed TMP is very safe and ...
In Japan, the Ningyo-toge uranium deposit was discovered in 1955, and the Tono deposit in 1962. Geology of these mines is different from that of other metal mines developed in Japan. Therefore, it appeared that some changes were required in the usual mining methods applied to existing metal mines to mine uranium ore in these deposits. At the Ningyo-toge mine, effective methods were studied for mining the ore, such as the room and pillar method, long-wall method, slicing method, and the hydraulic method; as a result, it was determined that a modified long-wall method is the most useful and practicable for recovering uranium ore from this underground sedimentary deposit. Applicatons of in-place and microbiological leaching to these deposits are being studied to secure mine safety and decrease mine pollution. Since 1959, when the Ningyo-toge mine went into operation, no hazards for workers nor any pollution of the environment were permitted. Research and development on uranium processing ...
Biomass is a potential source of energy that can reduce our dependency on oil as the main source of energy. In addition to municipal solid waste, animal and olive wastes are the main sources of organic waste in Jordan. In 2005, there were more than 2.4 million heads of sheep, about 72 thousand cows, and 40 million hens being raised in farms distributed in all governorates of Jordan. These animals produce 5.3 million tons (as exerted) of solid waste per year. If these quantities can be effectively collected they may constitute a valuable source of energy. This paper is aiming to estimate the amounts of animal and solid wastes generated in Jordan and their energy potential. The total amount of BOD from animal waste is estimated at 200,000 tons per year. Significant quantities of organic waste can also be collected from olive mills distributed in the country. This waste known locally as ''Jift'' is currently being collected and used ...
The environmental impacts of uranium mining and milling activities are of great concern in many countries for the last three decades. These impacts range from the creation of massive stockpiles of radioactive and toxic waste rock and sand-like tailings to serious contamination of surface and groundwater with radioactive and toxic pollutants, and releases of conventional, toxic and radioactive air pollutants. Uranium mining is also associated with high concentrations of highly toxic heavy metals, which are a major source of surface and groundwater contamination. Depending upon the hydraulic properties of the fractures involved, contaminated ground water may be transported many miles from its point of origin before feeding into an aquifer. Tailings pond may contaminate the groundwater regime by continuous seepage and leaching of radionuclides and other toxic metals due to interaction of rain water through the tailings ponds. The uranium milling ...
Naturally occurring radioactive materials (NORM) in seven new type wall materials were surveyed. The radioactivity was determined with HPGe-#gamma# spectrometer. The red mud has the highest radioactivity concentration, followed by slag building blocks, fly-ash building blocks (bricks), gangue bricks and light weight board materials, gypsum blocks. Fly-ash and slag contain higher NORM, which contributes the major part of the radioactivity in new wall materials. (authors)
This paper reviews the effects of neutron irradiation on thermal and mechanical properties and bulk tritium retention of armour materials (beryllium, tungsten and carbon). For each material, the main properties affected by neutron irradiation are described and the specific tests of neutron irradiated armour materials under thermal shock and disruption conditions are summarized. Based on current knowledge, the expected thermal and structural performance of neutron irradiated armour materials in the ITER plasma facing components are analysed.
This chapter discusses the types of natural radioactive materials in the environment that include primordial natural radioactive materials such as K-40, U and Th, and daughters of their decay series. The discussion also includes secondary natural radioactive material generated through cosmic radiation interaction with nucleus of materials in the atmosphere. The dispersion of these radioactive materials to environment will also be part of the discussion. (Author)
This heat exchanger is a critical step in the development of the Externally Fired Combined Cycle power system, a direct-coal combustion power plant (gas turbine). SiC is the only material with the needed resistance to creep, thermal shock, and oxidation; however a protective coating is needed. Ten candidate materials were identified: alumina-based materials, materials stable with SiO, and low expansion materials. An initial screening study should be performed.
Nuclear forensics is a relatively new scientific branch whose aim it is to read out material inherent information from nuclear material. On the basis of material taken in safe-keeping in Germany, the procedure is illustrated and the limits and possibilities of nuclear forensics are shown, in particular the statements that can be made concerning the material, and the relation of the material with respect to a certain location of origin or manufacturing process. (orig.)
This section of the report is concerned with the study of the metallisation, oxidation and doping of materials which are of importance to the micro-electronics industry. The Van de Graaff accelerator and radioactive tracers are used for studying surface and sub-surface behaviour of these materials.
... POSITION VACANT: Program Manager (Advance Materials and Manufacturing), AD-340-4. Salary ranges from ... POTENTIAL: Program Manager (Advanced Materials and Manufacturing), AD-340-4. LOCATION: Directorate ...
The amended Radiation Protection Ordinance of 2001 contains regulations on natural radioactive materials, whose recycling or disposal poses practical problems. There is little experience in this field so far.
The Energy crisis happens to be one of the greatest challenges we are facing today. In this view, much effort has been made in developing new, cost effective, environmentally friendly energy conversion and storage devices. The performance of such devices is fundamentally related to material properties. Hence, innovative materials engineering is important in solving the energy crisis problem. One such innovation in materials engineering is porous materials for energy storage. Porous electrode materials for lithium-ion batteries (LIBs) offer a high degree of electrolyte-electrode wettability, thus enhancing the electrochemical activity within the material. Among the porous materials, mesoporous materials draw special attention, owing to shorter diffusion lengths for Li+ and electronic movement. Nanostructured mesoporous ...
... Programmatic Terms and Conditions for the Materials Research Science and Engineering Centers (MRSEC ... NSF Grants Officer. 2. Program Description: Materials Research Science and Engineering Centers ...
... of Viscous Liquids, Glasses, and Crystalline Materials Under Extremes of Pressure and Temperature ... Materials 9624724 ENG AZ U of Arizona Gervay Jacquelyn Synthesis of Novel Materials Utilizing Sialic ...
... of the Evaluation of the Instructional Materials Development Program (PDF, 412 kb) Chapter I ... kb) Appendix 2: Instrument for Evaluating Materials (PDF, 935 kb) Appendix 3: Classroom Observation ...
The biocompatibility and corrosion resistance of various materials for use as sacrificial anodes in in vivo hybrid fuel cells were studied. Aluminium, zinc, and magnesium alloy AZ31B were studied, and the results are discussed.
Requirements for food packaging materials include whether there is any interaction between the food and the package during or after the irradiation, and whether as a result of the irradiation, volatile or leachable substances are released from the pack into the food. The performance of cellulose-based materials and plastic films under irradiation are discussed.
The Zhdanovka Coking Plant supplies materials for commercial use, e.g. ammonium sulfate and colloidal sulfur for agriculture and road-cementing materials. The method used for the production of colloidal sulfur is described briefly.
... 300710+Ceramic+Transactions+Series 2120%28Series+Code%29+Ceramic+Transactions+Series Wiley::Ceramic Transactions Series WILEY KNOWLEDGE FOR GENERATIONS United States Change Location Home ...CART | MY ACCOUNT | CONTACT US | HELP Home / Engineering & Materials Science / Materials Science / Ceramic Transactions Series Related Subjects Soft Matter Organic Electronics Structural Materials, ... Ceramics Structural Materials, Composites Structural Materials or Construction Materials Corrosion Electronics Materials Related Series Ceramic Engineering and Science Proceedings Wiley Series in Materials ...for Electronic and Optoelectric Applications Ceramic Transactions (CTs) books contain papers presented at the Annual Meeting of the American Ceramic Society, ...
... 300715+Ceramic+Engineering+and+Science+Proceedings 2122%28Series+Code%29+Ceramic+Engineering+and+Science+Proceedings Wiley::Ceramic Engineering and Science Proceedings WILEY KNOWLEDGE FOR ...CART | MY ACCOUNT | CONTACT US | HELP Home / Engineering & Materials Science / Materials Science / Ceramic Engineering and Science Proceedings Related Subjects Soft Matter Organic Electronics Structural ...Materials, Ceramics Structural Materials, Composites Structural Materials or Construction Materials Corrosion Electronics Materials Related Series Ceramic Transactions Series Wiley Series in Materials for ...Electronic and Optoelectric Applications Ceramic Engineering and Science Proceedings (CESP) contain proceedings from three American Ceramic Society (ACerS) meetings: ...
... exercises and biotechnology labs and didactic material. It includes sessions on computer and media ... computers, and learn how IPT activities and materials can help meet their curriculum objects ...
... and facilities; the physical processing of materials into products; and processes associated with ... area of bulk silicon prod! uction as wafer material has been omitted, in keeping with current ...
... information about, utilized, or discussed these subjects: basic topics: overview materials and material types: ti-6al-4v, ti1100, ti17 , ti6242, imi 550 ...
... and Engineering (NISE), Instructional Materials Development in Nanoscale Science and Engineering ... & Physical Sciences, Division of Materials Research, 1065 N, telephone: (703) 292-4937, email: lhess ...
... and (3) the exchange of information; materials or perspectives. In 1977, a conference of ... their peers), to products (e.g., curriculum materials, guidebooks, or videos). We will also take ...
... for the development of IT classroom materials for students or teachers, or for professional ... STEM education. Innovative instructional materials and student assessments, as well as new models ...
Material degradation of pressure tubes, which are the most important components in CANDU fuel channel, can only be evaluated by removing and examining them(material surveillance). This study aimed at establishment of overall evaluation technology including the evaluation of the material degradation for the integrity of pressure tubes of Wolsung units. Material tests for pressure tubes were performed as follows; (1) Evaluation on life limiting factors of pressure tubes (2) Review on leak-before-break and integrity maintenance technology of pressure tubes (3) Survey on selection criteria for tubes to be inspected and on related regulations for material surveillance (4) Analysis of material surveillance test procedure (5) Basic examinations of Wolsung unit 1 pressure tube material(TEM, texture, chemical component etc) (6) Manufacture of test ...
... education. It has fostered development of materials and techniques with the success of all, rather ... with Foundation staff to produce exemplary materials and models to help the nation attain its ...
Nanocrystalline and nanostructured materials offer unique microstructure-dependent properties that are superior to coarse-grained materials. These materials have been shown to have very high hardness, strength, and wear resistance. However, most current methods of producing nanostructured materials in weapons-relevant materials create powdered metal that must be consolidated into bulk form to be useful. Conventional consolidation methods are not appropriate due to the need to maintain the nanocrystalline structure. This research investigated new ways of creating nanocrystalline material, new methods of consolidating nanocrystalline material, and an analysis of these different methods of creation and consolidation to evaluate their applicability to mesoscale weapons applications where part features are often under 100 {micro}m wide and the ...
... teaching and learning; Creating learning materials and teaching strategies; Developing faculty ... achieve educational innovations. Educational Materials Development (EMD): A project under the former ...
... grants to adopt or adapt courses and materials developed by CCD projects at other institutions, and ... to adopt or adapt CCD-developed courses and materials. -iv- Accomplishments The CCD program has ...
... 4? Program History 5? Center for Advanced Materials and Smart Structures 6? Center for Systems ... Systems 14? Center for Photonic Materials Research 15? Synthesis, Manufacturing and Characterization ...
... Development for Envir Activities Materials Use: Sci, Eng, & Society Synopsis of Program: This ... for Environmental Activities (IDEA); Materials Use: Science, Engineering, & Society (MUSES). In all ...
New methods for the reduction and remediation of hazardous wastes like carcinogenic organic solvents, toxic materials, and nuclear contamination are vital to environmental health. Procedures for effective...Full Text Available
... By developing and disseminating educational materials and curricula, supporting the preparation and ... education, such as curriculum or educational materials development, faculty or teacher preparation ...
9 9 simulated Purex waste oxides was investigated as a function of Na/sub 2/O, CaO and P/sub 2/O/sub 5/ content. All compositions lost some sulfate at 50 to 100 deg C above the softening point. In generai the volatility decreased with increase of either Na/ sub 2/O or CaO relative to P/sub 2/O/sub 5/, but no simple correlation Was indicated. Softening temperatures were lowered by inc ease in Na/sub 2/O vs CaO. Ceramic solids were obtained but no true glasses. Attempts to produce glasses by addition of varying combinations of Al/sub 2/O/sub 3/, PbO, BaO, and B/sub 2/O/ sub 3/ to simulated Pure x waste plus phosphite were unsuccessful. The use of 0.005 M Na/sub 2/C/O/sub 3/ to precipitate calcium from wastes containing up to 3 ppm of phosphate was demonstrated in four pilot plant runs and produced a decrease in the hardness of the waste leaving the clarifier. An inadvertent Sr/ sup 90/ and Cs/sup 137/ breakthrough occurred during one run which was caused ...
In this study samples of AISI 4140 steel were pretreated by plasma nitriding and coated with two different physical vapour deposited coatings (TiN and TiAlN). A hardened AISI 4140 sample and a coated sample were also included in the investigation. To examine the influence of the nitrided zone on the performance of the coating-substrate composite, two different nitriding conditions - a conventional 25% N{sub 2} and an N{sub 2}-poor gas mixture - were used. The specimens were investigated with respect to their microhardness, surface roughness, scratch adhesion and dry sliding wear resistance. Wear tests in which the duplex-treated pins were mated to hardened ball bearing steel discs were performed in a pin-on-disc machine under dry sliding conditions. Metallography, scanning electron microscopy and profilometry were used to analyse the worn surfaces in order to determine the dominant friction and wear characteristics of the samples investigated. The results show ...
The Savannah River Site (SRS) is a 310-square-mile United States Department of Energy nuclear facility located along the Savannah River near Aiken, South Carolina. During operations, which started in 1951, hazardous substances (chemicals and radionuclides) were released to the environment. The releases occurred as a result of inadvertent spills and waste disposal in unlined pits and basins which was common practice before environmental regulations existed. The hazardous substances have migrated to the vadose zone and groundwater in many areas of the SRS, resulting in 515 waste units that are required by environmental regulations, to undergo characterization and, if needed, remediation. In the initial years of the SRS environmental cleanup program (early 1990's), the focus was to use common technologies (such as pump and treat, air stripping, excavation and removal) that actively and tangibly removed contamination. Exclusive use of these technologies required continued and significant ...
The thermal stability of low-friction Me-C/a-C:H coatings is important for their potential applications in the tool and automotive industry. Recently we showed that CrC _x/a-C:H coatings prepared by unbalanced magnetron sputtering of a Cr target in Ar + CH_4 glow discharges exhibit a nanocomposite structure where metastable fcc CrC nanocrystals are encapsulated by an a-C:H phase. Here, we present the structural evolution of these nanocomposite CrC/a-C:H coatings during annealing. High-temperature X-ray diffraction in vacuum and differential scanning calorimetry (DSC) combined with thermo-gravimetric analysis in Ar atmosphere indicate decomposition of the formed metastable fcc CrC phase and subsequent formation of Cr_3C_2 and Cr_7C_3 and structural transformation of the a-C:H matrix phase towards higher sp"2 bonding contents at temperatures above 450 deg. C. Combined DSC and mass spectrometer analysis as well as elemental profiling after annealing in vacuum by elastic recoil detection ...
The simulation of the Auxiliary Charcoal Bed (ACB) Vacuum System was performed to evaluate the original vacuum system design, detect and identify design deficiencies, investigate the effects of proposed corrections on system performance, and generally aid in refining the system design before construction and mockup testing. The simulation was performed by using the Advanced Continuous Simulation Language (ACSL). The vacuum system design goals are to provide approximately 20 SCFM of both booster gas and purge gas through the system and maintain a flow of approximately 40 SCFM with a velocity of 50 to 75 f/sec at the entrance to the cyclone separator. The model results showed that the original system design was incapable of meeting the system performance goals. Further simulations showed that the following modifications to the original vacuum system design were required to make the system performance acceptable; (1) Remove valve PCV4. (2) Modify the flow controllers FTC3 and FTC4 from ...
Gas quenching for the hardening of steel parts is a lower-pollution alternative to quenching in quenchants such as oil or salt. As the surfaces of the cooled parts remain clean after gas quenching, there is no need to wash them after heat treatment, which reduces the consumption of oils and detergents. The fire risk and ventilation requirements of oil quenching are eliminated. In addition, some trials have shown that gas quenching has a positive effect on distortion, representing a saving in finishing work and thus a reduction in costs. Today, gas quenching is used almost solely in vacuum furnaces. Quenching is normally performed in the same chamber as heating, which means that besides quenching the batch, the quenching system must also remove heat from the heating elements and insulation of the furnace. Previous trials performed by IVF have shown that gas quenching with helium of ball bearing and carburizing steels (and other steels) in sizes up to 25 mm at ...
Thermo-reactive diffusion chromizing followed by pulsed plasma nitriding were carried out on AISI 52100 and 8620 bearing steels. The chromized samples were pulse-plasma nitrided for 5 h at 500 deg. C in various N_2-H_2 gas mixtures. The coated steels were characterized using scanning electron microscopy, X-ray diffraction and microhardness testing. The unlubricated wear behaviors of only chromized and duplex treated steels were investigated in ball-on-disc system tests at room temperature. X-ray diffraction patterns of the duplex treated samples containing H_2 indicated the formation of dominant CrN and Cr_2N nitrides as well as the formation of Cr_3C_2 and Cr_7C_3 carbides. Gas mixtures in the plasma nitriding, which was performed after chromizing, have a significant influence on the wear rate of the duplex treated steels. The wear and friction tests showed that the lowest friction coefficient and wear rates were observed for the samples duplex treated in a 50%N_2 ...
The topics of these short lectures on the subject of cyclic stress were: Microstructural mechanisms of damage accumulation under a multistage cyclic stress until incipient cracking; influence of surface decarbonizing phenomena on the failure behaviour of steel construction parts subjected to cyclic stress; thermocyclic fatigue of pipe samples of austenitic steel 1.4436; studies on surface structuring, microstructure and fatigue in LCF area. The short lectures on effects of quasi-static and creep stress were: Shear fracture in AlMg alloys as a result of local plastic instability; study of formation and growth of pores for an early recognition of damage and the course of damage in heat-resistant steels under creep test; experimental and numeric studies of the infuence of the microstructure on the course of damage during shear fractures of steel; numerical modelling of ductile fractures on the basis of micromechanical models. Under the topic of tribological stress the following lectures ...
A number of screening tests were performed to determine ion species that effectively reduce wear rates when implanted in four industrial steels. Ball bearing steel 100Cr6 (AISI 52100) showed a wear rate reduction by a factor of 20 when implanted with carbon dioxide to a dose of 5x10{sup 17} cm{sup -2} with a non-mass-separated ion beam and by a factor of {>=}20 when implanted with 5x10{sup 17} cm{sup -2} oxygen ions. For the ferritic and martensite steels X90CrMoV18 (AISI 440B, unhardened and hardened) also a strong wear reduction after implantation of oxygen ions was found. Co-implantation of aluminum and oxygen also reduces wear rates of X90CrMoV18, of S6-5-2 (AISI M2), and of 100Cr6, respectively. For comparison, thin oxide layers were grown in a low-temperature thermal oxidation process. These experiments also yielded reduced wear rates by a factor of 10. The surfaces were investigated and characterized by XPS, SIMS, TEM, and microhardness measurements to ...
Small droplets of organic diazides investigated by C.K. Law and coworkers burn in hot gas at 1 atm with rates inversely proportional to the droplet diameter presumably owing to leading chemical reaction proceeds in gas phase. These burning rates are obviously much lower than those obtained by extrapolation of the results measured for the some substances in glass tubes (at pressure of about 10{sup -2}-10{sup -1} atm, and temperature 0-100 deg C) on the burning conditions of the droplets. Kinetic constants estimated using Zel`dovich equation for the burning rate in gas phase and Semenov relation for delay time of the droplets micro-explosion in liquid phase are about the same: E {approx_equal} 0.17 MJ/mol, log{sub 10}k{sub o} {approx_equal} 15(S{sup -1}). In both of the cases the leading chemical reaction is supposed to be of the first order. Landau instability is assumed to be reflected in distortion of the droplets at burning but, as opposed to the liquids pools or columns burning, it ...
Cassava chips (cassava balls, and cassava pellets) are derived cassava products traditionally produced by farmers in sub-Saharan Africa following fermentation, and drying of fresh roots of cassava, and are widely consumed in Cameroon. Once produced, this food commodity can be stored for more than two months and contaminated by a wide array of harmful microbes. In order to assess persistence of toxigenic fungi in cassava chips, aflatoxin-producing fungi (Aspergillus flavus, Aspergillus nomius, and Aspergillus parasiticus) and aflatoxins were contrasted at regular intervals in home-stored cassava chips collected in two locations of southern Cameroon throughout a two-month monitoring period. Three hundred and forty-six isolates of aflatoxin-producing fungi were found to be associated with all samples. A. flavus contaminated more samples in both types of chips (267 isolates in 53 samples), followed by A. nomius (58 isolates in 15 samples), whereas A. parasiticus was ...
Chitosan-filled rubber compounds were prepared using a laboratory sized two-roll mill. The effect of chitosan loading on three different types of rubber (STR 5L, ENR-25 and SBR) was investigated. The results indicate that, overall, the scorch time (t"S"2), cure time (t"9"0), tensile strength and elongation at break (Eb) decrease with chitosan loading, whereas an increment was observed in the maximum torque (MH) and the tensile modulus (M100 and M300) of all three types of rubber. At a similar chitosan loading, the cure characteristics of SBR were found to be longer (for t"S"2 and t"9"0) and higher (for MH) than those of STR 5L and ENR-25. The tensile properties of SBR were found to be the lowest of the three rubbers at a similar chitosan loading. The rubber-filler interaction for all three...
Orujillo, sometimes called wood matter from pressed oil-stone (WPOS) is a residue from the olive oil mill industry. The generation of this biomass residue is concentrated in small areas allowing its use as fuel for medium size gasification and combustion plants. Rates of gasification of WPOS char were measured in a TGA at various temperatures (800-850-875-900-950{sup o}C), CO{sub 2} partial pressures (0.20-0.35-0.50 bar) and CO partial pressures (0.0-0.20 bar). The experiments were carried out with a monolayer bed of very fine particles well exposed to the gas so as to minimise mass and heat transfer resistances. Two kinetic models, the nth order model and Langmuir-Hinshelwood model, have been used to fit with the reactivity data. For pure CO{sub 2} experiments the kinetic parameters of nth order model were E=133 kJ/mol and n=0.43. The Langmuir-Hinshelwood kinetic model clearly describes the observed CO inhibition effect on the CO{sub 2} gasification.(author)
We have investigated the nanotexture and crystallographic orientation of aragonite in a coral skeleton using synchrotron-based scanning transmission X-ray microscopy (STXM) and transmission electron microscopy (TEM). Polarization-dependent STXM imaging at 40-nm spatial resolution was used to obtain an orientation map of the c-axis of aragonite on a focused ion beam milled ultrathin section of a Porites coral. This imaging showed that one of the basic units of coral skeletons, referred to as the center of calcification (COC), consists of a cluster of 100-nm aragonite globules crystallographically aligned over several micrometers with a fan-like distribution and with the properties of single crystals at the mesoscale. The remainder of the skeleton consists of aragonite single-crystal fibers in crystallographic continuity with the nanoglobules comprising the COC. Our observation provides information on the nm-scale processes that led to biomineral formation in this ...
The effects of thiosulfate ion and solution pH on pitting corrosion of Alloy 690 in chloride solution were explored. Potentiodynamic polarization measurements were conducted to evaluate pitting corrosion susceptibility of Alloy 690 in these environments. The results showed that pitting corrosion occurred in the mill-annealed (1050 deg. C/5min) Alloy 690 in 1 wt% NaCl solution but not in 0.1 M Na{sub 2}S{sub 2}O{sub 3} solution. The value of pitting nucleation potential (E{sub np}) determined in 1 wt% NaCl solution (without Na{sub 2}S{sub 2}O{sub 3} ) increased with increasing solution pH value in the range of 2-10. The addition of Na{sub 2}S{sub 2}O{sub 3} to 1 wt% NaCl solution greatly affected the pitting corrosion behavior, which was dependent on concentration. The preformed nickel sulfide surface film due to the presence of Na{sub 2}S{sub 2}O{sub 3} caused Alloy 690 to become more susceptible to pitting corrosion in 1 wt% NaCl solution.
Recently we discovered and discussed non-Abelian duality in the quark vacua of N=2 super-Yang-Mills theory with the U(N) gauge group and N_f flavors (N_f>N). Both theories from the dual pair support non-Abelian strings which confine monopoles. Now we introduce an N=2-breaking deformation, a mass term \\mu{\\mathcal A}^2 for the adjoint fields. Starting from a small deformation we eventually make it large which enforces complete decoupling of the adjoint fields. We show that the above non-Abelian duality fully survives in the limit of N=1 SQCD, albeit some technicalities change. For instance, non-Abelian strings which used to be BPS-saturated in the N=2 limit, cease to be saturated in N=1 SQCD. Our duality is a distant relative of Seiberg's duality in N=1 SQCD. Both share some common features but have drastic distinctions. This is due to the fact that Seiberg's duality apply to the monopole rather than quark vacua. More specifically, in our theory we deal with ...
Focused ion beam (FIB) irradiation of a thin Ni_2Si layer deposited on a Si substrate was carried out and studied using an in-situ transmission electron microscope (in-situ TEM). Square areas on sides of 4 by 4 and 9 by 9 microm were patterned at room temperature with a 25 keV Ga"+-FIB attached to the TEM. The structural changes of the films indicate a uniform milling, sputtering of the Ni_2Si layer and the damage introducing to the Si substrate. Annealing at 673 K results in the change of the Ni_2Si layer into an epitaxial NiSi_2 layer outside the FIB irradiated area, but several precipitates appear around the treated area. Precipitates was analyzed by energy dispersive X-ray spectroscopy (EDS). Larger amount of Ni than the surrounding matrix was found in precipitates. Selected area diffraction (SAD) patterns of the precipitates and the corresponding dark field images imply the formation of a Ni rich silicide. The relation between the FIB tail and the ...
Faulting the feedwater for a 19-tube, model steam generator with 10 ppM of caustic once a week produced widespread shallow 25 to 75 micrometers (1 to 3 mils) intergranular attack (IGA) on alloy 600 tubes and an axial tube rupture at the steam-water interface after 4.8 years. An extensive investigation of the IGA damage found little correlation with major test variables beyond the indication that mill-annealed tubing was more susceptible to attack than stress-relieved tubing. The most likely cause of the tube rupture was caustic that concentrated to high levels in a porous scale on the tube at the liquid-vapor interface where there was a high available superheat. Nondestructive examination (NDE) eddy current probes underestimated the depth of IGA and were not sensitive to circumferential cracks less than 152 micrometers (6 mils) deep that were above and below the roll transition zones of tubes in the tubesheet.
This prospective study describes and evaluates a surgical approach for 3D reconstruction of the posterior maxilla with autogenous mandibular bone in 16 patients (mean age 51 years). Bone blocks were harvested from the mandible and used as lateral or vertical block grafts (onlay); they were also partially milled and used for sinus elevation (inlay). In 4 cases, anorganic bovine bone was added at the periphery of the blocks. 4 months after grafting, implants were placed in a second operation and loaded after 12 weeks. Lateral and vertical augmentations were measured immediately after grafting and at re-entry for implant placement. Mean lateral augmentation performed was 5.5mm, reduced to 4.3mm (p<0.01) after 4 months' healing. Mean vertical augmentation was 3.2mm, reduced to 2.1mm (p<0.01) a...
A solution based on sludge and Olive oil mill effluent (OME) co-digestion, coupled with a management plan, has been implemented, to treat and dispose safely, the mixed residues, into the natural forest and agricultural land. The mixture of up to 25% OME to the sludge improved anaerobic degradation of phenols and fats. High density fat compounds, present in OME, enhanced aggregation, settling and acetoclastic activity of anaerobic sludge. The full scale unit, obtained by modification of a cold digester, allowed to set-up a low capital cost system. The system produced large quantity of biogas and electric energy. Anaerobic degradation of the mixture improved fertilizing properties, making feasible land application of the digested mixture. Regional plan based in Geographical Information System (GIS) selected 800 ha of adequate land area for application near the WWTP. The experience is technically and economically successful. Main incomes are provided by energy use and ...
High aspect ratio sub-#mu#m periodic structures fabricated by focused ion beam (FIB) lithography have been characterised by Rutherford backscattering spectrometry (RBS) using the macrochannelling technique. The technique overcomes the limitations of complementary techniques such as scanning electron microscopy (SEM) and atomic force microscopy (AFM), which can provide images with sub-#mu#m resolution of just the surface features and not of the deep sub-surface structures, without destructive cross sectioning of the sample. Here RBS macrochannelling with a 2 MeV He"+ ion beam is used to analyse a diffraction grating fabricated by FIB milling an array of 100 nm wide trenches in a 300 nm thick Ag film on a Si substrate. Using the surface structure imaged by SEM and AFM as a starting point, a numerical model for the RBS spectrum from the grating is fitted to the experimental spectrum as a function of the sub-surface structure. This process allows the width of the ...
We present two new techniques that enhance conventional focused ion beam (FIB) system capabilities for integrated circuit (IC) analysis: in situ electrical biasing and voltage contrast imaging. We have used in situ electrical biasing to enable a number of advanced failure analysis applications including (1) real time evaluation of device electrical behavior during milling and deposition, (2) verification of IC functional modifications without removal from the FIB system, and (3) ultraprecision control for cross sectioning of deep submicron structures, such as programmed amorphous silicon antifuses. We have also developed FIB system voltage contrast imaging that can be used for a variety of failure analysis applications. The use of passive voltage contrast imaging for defect localization and for navigation on planarized devices will be illustrated. In addition, we describe new, biased voltage contrast imaging techniques and provide examples of their application to ...
The analytical treatment of the nonperturbative QCD dynamics is one of the main open questions of the strong interactions. Currently, it is only possible to get some qualitative information about this regime considering other QCD-like theories, as, for example, the N=4 super Yang-Mills theory, where one can perform calculations in the nonperturbative limit of large 't Hooft coupling using the anti-de Sitter space/conformal field theory (AdS/CFT). Recently, the high energy scattering amplitude was calculated in the AdS/CFT approach, applied to deep-inelastic scattering and confronted with the F_2 HERA data. In this work we extend the nonperturbative AdS/CFT inspired model for diffractive processes and compare its predictions with a perturbative approach based on the Balitsky-Kovchegov equation. We demonstrate that the AdS/CFT inspired model is not able to describe the current F_2"D"("3") HERA data and predicts a similar behavior to that from the Balitsky-Kovchegov ...
Electron probe microanalysis (EPMA) offers high sensitivity and high accuracy in quantitative measurements of chemical compositions and mass coverages. Owing to the low detection limits of the wavelength-dispersive technique, monolayers with mass coverages of about 0.05 pg cm z can be detected. Assuming a density of 5 g cm--3 this corresponds to a thickness of 0.1 nm. With these advantages in mind, EPMA was extended to depth profile analysis in the sub-micron range using a surface removal technique. The present paper shows how depth profile analysis can be improved by combining EPMA and the focused ion beam (FIB) technique. The focused ion beam system uses a Ga+ ion beam. The ion beam allows the milling of defined geometries on the nanometer scale, so that very shallow bevels with exactly defined angles in relation to the surface can be obtained. Low surface damage is expected due to low sputtering effects. Calibrated WDX measurements along the bevel deliver ...
We study the condensation of localized closed string tachyons on AdS orbifolds both from the bulk and boundary theory viewpoints. We first extend the known results for AdS{sub 5}/Z{sub k} to AdS{sub 3}/Z{sub k} case, and we proposed that the AdS{sub 3}/Z{sub k} decays into AdS{sub 3}/Z{sub k'} with k{sup '} < k. From the bulk viewpoint, we obtain a time-dependent gravity solution describing the decay of AdS orbifold numerically. From the dual gauge theory viewpoint, we calculated the Casimir energies of gauge theory vacua and it is found that their values are exactly the same as the masses of dual geometries, even though they are in different parameter regimes of 't Hooft coupling. We also consider AdS{sub 5} orbifold. The decay of AdS{sub 5}/Z{sub k} is dual to the transition between the vacua of dual gauge theory on R{sub t} x S{sup 3}/Z{sub k}. We constructed the instanton solutions describing the transitions by making use of instanton solutions on ...
The centre of the symmetric group algebra $\\mathbb{C}[\\mathfrak{S}_n]$ has been used successfully for studying important problems in enumerative combinatorics. These include maps in orientable surfaces and ramified covers of the sphere by curves of genus $g$, for example. However, the combinatorics of some equally important $\\mathfrak{S}_n$-factorization problems forces $k$ elements in $\\{1,...,n\\}$ to be distinguished. Examples of such problems include the star factorization problem, for which $k=1,$ and the enumeration of 2-cell embeddings of dipoles with two distinguished edges \\cite{VisentinWieler:2007} associated with Berenstein-Maldacena-Nastase operators in Yang-Mills theory \\cite{ConstableFreedmanHeadrick:2002}, for which $k=2.$ Although distinguishing these elements obstructs the use of central methods, these problems may be encoded algebraically in the centralizer of $\\mathbb{C}[\\mathfrak{S}_n]$ with respect to the subgroup $\\mathfrak{S}_{n-k}.$ ...