Radiation-and-thermal-combined degradation of some kinds of cable insulating and jacketing materials was evaluated by accelerated aging tests. Plasticized polyvinyl chloride (PVC), silicone rubber, crosslinked and non-crosslinked halogen-free flame-retardant polyolefins (NH-XLPO and NH-PO) and ethylene-propylene rubber (EP rubber) of experimental formulation were degraded at accelerated rates, that are 50-1000 times the degradation rate under standard conditions (e.g.; 1Gy/h, 50degC), and a method to assess the lifetime of these materials under standard conditions was studied. The degradation was investigated by measuring tensile properties. In the accelerated aging tests, rates of elongation decrease owing to degradation for these materials were in proportion to the increase in accelerated rate. The PVC lifetime estimated from sequential aging tests had a tendency to extend beyond that from ...
Optimum conditions for the rapid, efficient, nondestructive determination of rubber producing potential in guayule (Parthenium argentatum) were established. The rubber producing potential...Full Text Available
Combinations of exposure concentrations, durations and frequencies were tested in four-week inhalation exposures followed by two weeks of recovery to define the interactive effects of these variables on biologic responses and to select the most-sensitive biologic response parameters for the subsequent subchronic studies. Response surface modeling was used for the experimental design and statistical analysis of the data. Results of preliminary testing suggested that exposure duration and frequency did not have major effects. Subsequently, male and female Sprague-Dawley rats were exposed in separate studies to RP/BR aerosols ranging from 0.40 to 1.20 mg/1 or to filtered air for 2.25 hr/day on four days/week for four weeks. Test-atmosphere monitoring data demonstrated that aerosol concentrations were consistently within 4% of the target values and mean particle size ranged from 0.44-0.64 ..mu..m with mean sigma g's of 1.66-1.97. During the exposure period, wheezing and labored ...
Enzyme kinetic studies from this laboratory (M. Dobersen and S. Greer, Biochemistry 17:920-928, 1978) suggested that deoxycytidine could antagonize the toxicity of 5-halogenated analogs of deoxycytidine...Full Text Available
The use of Funtumia latex and nitrobenzene as molecular weight depressants for natural rubber was studied. Portions of a given sample of natural rubber latex were treated with these materials, and this provided a means of ascertaining the amount of Funtumia latex in a blend with natural rubber that could produce a lowering of the molecular weight equivalent to that from known concentrations of nitrobenzene in natural rubber latex. The molecular weight of the products decreased to an equilibrium value after 10 h of reaction with nitrobenzene. The calculations revealed that a 27.9% substitution of natural rubber latex (300 mL) with Funtumia rubber latex achieved the same result as nitrobenzene in the same polymer at concentrations of 0.5-2.0 wt % of the dry rubber content of the latex after ...
Skim natural rubber latex is a protein-rich byproduct obtained during the centrifugal concentration of natural rubber latex. Skim latex has a very low dry rubber content (4-8%), and the rubber particles are smaller in size. It has a higher proportion of nonrubber solids, which are mostly proteinaceous in nature. It is difficult to coagulate, and it takes more processing time. The proteins in skim latex can be decomposed by proteolytic enzymes. This article discusses the use of stabilized liquid papain from the papaya plant (Carica papaya) for deproteinization followed by creaming for quick and easy coagulation of skim latex. The technological properties and aging characteristics of the deproteinized skim rubber are compared with those of conventionally prepared skim rubber and block rubber...
This study was composed of three parts: a post cure study to optimize final properties of an ethylene-propylene-diene (EPDM) formulation, an accelerated aging study to compare the stress relaxation behavior of a butyl and an EPDM elastomer under compression, and a cursory evaluation of a new 70 Shore A EPDM. The optimum postcure for the EPDM was found to be 2 to 4 hours at 182{degrees}C in a vacuum. The EPDM was also shown to have superior aging characteristics compared to the butyl and is recommended for use instead of the butyl material. The physical properties for new 70 Shore A EPDM are satisfactory, and the stress relaxation behavior was only slightly inferior to the other EPDM.
Occupational exposure to N-nitrosamines in the rubber industry was first reported by Fajen et al. (1979). In order to study the origin and formation of nitrosamines in this industry, chemicals and industrial products, as well as the air in various working areas, were analysed. All chemicals used for rubber compounding contain nitrosamines if they are derivatives of secondary amines; e.g., tetramethylthiurame, zinc-diethyldithiocarbamate or N-oxydiethylene benzothiazolylsulfenamide. All rubber products containing these dialkyl amine derivatives exhibited considerable levels of the corresponding nitrosamines. Accordingly, variable concentrations of airborne nitrosamines could be detected at places where rubber products are manufactured or stored. The nitrosamines found correspond to the compounded chemicals. The original nitrosamine level in rubber chemicals is not high enough to ...
A solid electrolyte cell comprises an alkali metal anode, e.g. lithium, a halogen-containing organic polymer cathode and a solid elecrolyte between the anode and the cathode. The cathode comprises iodine-containing vacuum-cyclised polyacrylonitrile, and the solid electrolyte is preferably lithium iodide and halogen-free vacuum-cyclised polyacrylonitrile. This patent also discloses the use of isotactic polyacrylonitrile, a method of making a cathode comprising iodine-containing vacuum-cyclised polyacrylonitrile, and novel methods of making the solid elecrolyte cells described.
Silica-reinforced natural rubber (NR) composite was prepared by using tetraethoxysilane (TEOS) as a precursor to generate silica particles inside the rubber. The silica was generated in situ by the sol-gel process of TEOS that was mixed directly into commercial-graded NR latex having 60% dry rubber content and 0.7% ammonia. The conversions of TEOS to silica inside the rubber were ranging from 90 to 97%. The silica particles dispersed evenly without extensive aggregation with sizes between 100 and 500 nm, as determined by scanning electron microscopy (SEM). An experimental design methodology, namely "two-level factorial design," was used to evaluate the influence of the amounts of TEOS, ammonia, and gelation time on the tensile modulus, tensile strength, and tear strength of the vulcanizate...
Carbon black is widely used as an active filler in the rubber industry to improve the physical properties of rubber. The surface energy of carbon black is high compared to that of various elastomers like styrene?butadiene rubber (SBR), butadiene rubber (BR) and ethylene?propylene?diene rubber (EPDM). The work aims at reducing the surface energy of carbon black by modifying its surface for application especially in rubber blends. The present paper looks into the possibility of using plasma polymerisation of acetylene as a surface modification technique for carbon black in comparison with silica. Thermogravimetric analysis, wetting behaviour with various liquids of known surface tension and time of flight secondary ion mass spectrometry (ToF-SIMS) were used to characterise the carbon black b...
This work reports a systematic comparative study of the technological properties of natural lattices and rubbers extracted from Hancornia speciosa Gomes and Hevea brasiliensis [(Willd. ex Adr. de Juss.) Muell.-Arg.] (clone RRIM 600) trees from 11 collections in Brazil throughout 2004. Natural rubber latex particle sizes and distributions were quite similar with an average diameter around 1 mm. Molecular weight, Wallace plasticity, and Mooney viscosity values were approximately the same for both rubbers. Fourier transform infrared spectroscopy peaks characteristic of natural rubber were observed for both Hancornia and Hevea. The measured differences in technological properties included lower values for Hancornia dry rubber content, % ash, % nitrogen, and plasticity retention index but highe...
This invention relates to polyalkylenes which contain both halogen and ester groups, to the preparation thereof, and to the use thereof as pour depressants for fuel oils. This invention also relates to polyalkylene esters.
Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and...Full Text Available
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...
1. β-Hydroxy-β-methyl[3-14C]glutaryl-CoA is efficiently incorporated into rubber on incubation with Hevea brasiliensis latex, and the incorporation is diminished...Full Text Available
Natural rubber latexes were vulcanized by ..gamma..-rays with two polyfunctional monomers, neopentylglycol diacrylate (A-NPG) and dimethacrylate (NPG). In comparison with A-NPG, NPG was more soluble in rubber particles, but it was less effective as an accelerating agent for the vulcanization because of the smaller rate of polymerization. On the other hand, the colloidal stability of the latex containing A-NPG was low because it was localized on the surface of rubber particles due to its poor solubility to the particles. The solubility of A-NPG was improved by adding A-NPG with solvents. The maximum tensile strength of the irradiated latex film was 350 kg/cm/sup 2/ at 3 Mrad.
Natural rubber latexes were vulcanized by #gamma#-rays with two polyfunctional monomers, neopentylglycol diacrylate (A-NPG) and dimethacrylate (NPG). In comparison with A-NPG, NPG was more soluble in rubber particles, but it was less effective as an accelerating agent for the vulcanization because of the smaller rate of polymerization. On the other hand, the colloidal stability of the latex containing A-NPG was low because it was localized on the surface of rubber particles due to its poor solubility to the particles. The solubility of A-NPG was improved by adding A-NPG with solvents. The maximum tensile strength of the irradiated latex film was 350 kg/cm"2 at 3 Mrad. (author).
A comparative test in mice for pulmonary toxicity between butylated hydroxytoluene (2,6-di-tert.-butyl-4-methylphenol, BHT) and 2,6-di-tert.-butyl-4-(alpha, alpha, alpha-2H3)methylphenol (BHT-d3) showed a significantly lower toxic potency of the latter. The rate of in vitro BHT metabolism to 2,6-di-tert.-butyl-4-methylene-2,5-cyclohexadienone (BHT-QM) was slowed by deuterating BHT in the 4-methyl group. On the other hand, the rate of in vitro metabolism to 2,6-di-tert.-butyl-4-hydroxy-4-methyl-2,5-cyclohexadienone (BHT-OH) was increased with the deuteration. A similar isotope effect of the deuterium substitution on the in vivo metabolic rates of BHT was observed. These observations support the concept that the lung damage caused by BHT is mediated by BHT-QM. The pulmonary toxicity of 2-tert.-butyl-4-ethylphenol (4-EP) and their deuterated analogs was also ...
The suitability of using the microwave oven for the rapid determination of total solids content (TSC) of natural rubber latex has been established over a broad range of dry rubber content (DRC). The total solids content values obtained by the microwave oven method are compared with the values obtained by heating in a conventional convection oven. Heating in a microwave oven is advantageous as the measurement time could be reduced considerably.
Results from scanning electron microscopy, Fourier transform infrared spectroscopy and the measurement of thermally stimulated current show that a high density of the physical defects and the chemical defects are introduced into the surface of the silicone rubber plates after they are treated by corona discharge plasma. These defects behave electrically as shallow electron traps, leading to the formation of a uniform discharge in air at higher pressure when the corona-modified silicone rubber is used in dielectric barrier discharge.
Laser direct-write etching of the refractory metals Mo and W was developed using reactions in chlorine and nitrogen trifluoride vapors. Rate and high spatial resolution are simultaneously optimized using a two-vapor halogenation/development sequence, based on surface modification. Local-area laser chlorination of the metal surface is used to predispose areas to subsequent bulk etching.
Metam sodium (metam) is a widely used soil fumigant. Combined application of metam and other available fumigants is intended to produce synergic pesticidal effects for a broad spectrum of pest control in soil fumigation. This study aimed to test the compatibility of metam with the halogenated fumigants 1,3-dichloropropene (1,3-D), chloropicrin, methyl bromide, methyl iodide and propargyl bromide. Halogenated fumigants and metam were spiked simultaneously into organic solvents, water and moist soils, and metam-induced degradation of these halogenated chemicals was evaluated. In all three media, the halogenated fumigants were incompatible with metam and degraded via rapid chemical reactions. The degradation rate varied with halogenated fumigant species and increased as the amount of metam present was increased. In moist soil, 15-95% of the halogenated fumigants ...
Cyclization of deproteinized natural rubber (DPNR) or purified natural rubber latex was effectively performed in latex phase by using trimethylsilyl-trifluoromethane sulfonate or trimethylsilyl triflate (TMSOTF) as a novel catalyst, which is still not reported in the case of natural rubber latex. Various cyclization conditions affecting the degree of cyclization were studied, such as dry rubber contents, temperature, TMSOTF concentrations, and time. The cyclized products were characterized by FTIR, Raman, 1H-, and 13C-NMR spectroscopies, as well as DSC and TGA. The degree of cyclization was estimated by 1H-NMR spectrum. It was found that the degree of cyclization in NR was a function of cyclization conditions. The thermal stability of cyclized DPNR increased with the degree of cyclization....
The Thai natural rubber economy is described in the context of the world rubber market. An econometric model is estimated for 15 structural equations; it includes the Thai, US, and rest-of-the-world rubber economies. Several simulation experiments are analyzed for the period from 1984 to 1995. Impact and dynamic multipliers are reported for major endogenous variables in response to changes in US GDP, world crude oil price, Thai replanting cess tax and Thai natural rubber production. A 1%, one-time increase in the US GDP has a positive effect on the Singapore natural rubber price. A world crude oil price decline shock has a negative effect in both the short-run and the long-run. The INRO buffer stock stabilization policy as well as alternative domestic Thai policies of market intervention are analyzed. The simulation results show that buffer stock management which allows a price band ...
Wood/polymer composites (WPC) have been prepared from pinewood with different compounds using gamma irradiation: butyl acrylate, butyl methacrylate, styrene, acrylamide, acrylonitrile, and unsaturated polyester styrene resin. The polymer loading was determined with respect to the compound concentration and the irradiation dose. The polymer loading increases generally with increase in the monomer or polymer concentration. Tensile and compression strength have been improved in the four cases, but no improvement was observed using unsaturated polyester styrene resin or acrylamide.
Laser flash photolysis studies of tetraphenyl-p-dioxin have led to the characterization of its triplet state. The T-T absorption spectra shows maxima at 350 and 545 nm; the triplet has a lifetime of 535 ns in methanol and can be quenched by di-tert-butyl nitroxide, paraquat dications, oxygen, and di-tert-butyl selenoketone. The interaction of the triplet with oxygen leads to the formation of singlet oxygen which in turn reacts with the title compound to yield benzil.
Compared to yeast esterase, fungal cutinase degraded butyl benzyl phthalate (BBP) far more efficiently; i.e., almost 60% of the BBP disappeared within 7.5 h. Also, the final chemical composition significantly...Full Text Available
Ion beams of halogens can be produced either positively or negatively charged, depending on the employed ion source. At CERN-ISOLDE, although positively charged fluorine and astatine can be obtained from a hot plasma ion source, they are often contaminated by isobars and molecular sidebands. This has generated a request from the scientific community for fluorine and astatine negative ion beams free of contaminants. The high selectivity ensured by the surface ionisation process also makes negative beams of chlorine, bromine and iodine highly attractive. However, the efficiency figures for negative surface ionisation of fluorine and astatine were lower than the ones from the hot plasma. Here we report our R and D on new surface ion sources suitable for the production of negative halogen beams.
A Michelson interferometer and a CCD detector were used to measure the number of interference fringes related to the expansion length of rubber sample. The sample was situated in a microcryostat, and the temperature of the sample was varied from -200 .deg. C to +80 .deg. C. Various types of carbon black filled rubber (Duradene, Sn-SSBR) samples were used to determine the glass transition temperatures (T_g) and the thermal coeffcients (#alpha#). The mixing ratio was 0, 10, 30, 40, 50, or 70 parts per hundred of carbon black to Sn-SSBR rubber. For the unfilled rubber of Sn-SSBR, the T_g was about -24 .deg. C, and the thermal coeffcient was 1.18 X 10"-"4 .deg. C"-"1. The thermal coeffcients sharply increased around T_g for all samples, and decreased with increasing doping ratio of carbonblack from 0 .deg. C to 30 .deg. C. The volume resistivity was measured for natural rubber and EPDM ...
The synthesis and degradation of anthropogenic and natural organohalides are the basis of a global halogen cycle. Chlorinated hydroquinone metabolites (CHMs) synthesized by basidiomycete fungi and present...Full Text Available
A process for the generation of halogens from halide-containing solutions includes the step of conducting electrolysis of the solutions in an electrolytic cell having a platinum based amorphous metal alloy anode.
Despite their structural resemblance, a pair of cyclic halogenated compounds, 1-chloro-1,2,2-trifluorocyclobutane (F3) and 1,2-dichlorohexafluorocyclobutane (F6), exhibit completely different anesthetic...Full Text Available
Sphingomonas (formerly Pseudomonas) paucimobilis UT26 utilizes γ-hexachlorocyclohexane (γ-HCH), a halogenated organic insecticide,...Full Text Available
Sphingomonas (formerly Pseudomonas) paucimobilis UT26 utilizes γ-hexachlorocyclohexane (γ-HCH), a halogenated organic insecticide,...Full Text Available
Abstract Series of typical -type and pseudo--type halogen-bonded complexes BClY and BBrY and hydrogen-bonded complex BHY (B = C2H4, C2H2, and C3H6; Y = F, Cl, and Br) have been investigated using the MP2/aug-cc-pVDZ method. A striking parallelism was found in the geometries, vibrational frequencies, binding energies, and topological properties between BXY and BHY (X = Cl and Br). It has been found that the lengths of the weak bond d(X)/d(H), the frequencies of the weak bond (X)/(H), the frequency shifts (XY)/(HY), the electron densities at the bond critical point of the weak bonds c(X)/c(H), and the electron density changes c(XY)/c(HY) could be used as measures of the strengths of typical -type and pseudo--type halogen/hydrogen bonds. The typical -type and pseudo--type halogen bond and hyd...
Major factors that contribute to maximized impact resistance of semicrystalline engineering polymers include increased matrix molecular weight, minimal rubber glass-transition temperature, and optimal rubber-particle size, which depends on matrix type. Additional constraints are posed by the limitations of available materials and commercial requirements. Expanding the understanding of impact-modified crystalline engineering polymers will further extend their property ranges and utility. This chapter describes the phenomenology of certain factors, illustrates a new technique to measure rubber particle size, and contrasts the fracture mechanisms of poly(butylene terephthalate), nylon 66, and polyacetal. 49 refs., 24 figs.
The aim of this study is to prepare some polymeric moulds using Natural rubber latex (NRL)- portland cement composites based on a delayed-action mechanism. Factors affecting the preparation process such as concentration, mixing percentage, additives and their effects on what is regarded as a delayed-action coacervant combination was studied. The effect of Gamma-radiation on the mechanical properties of these moulds was investigated. The effect of natural aging on the prepared moulds was investigated to determine the possibility of using the prepared product in the construction field as expansion joints and cracks filling materials ...etc. The results may be summarized as follows: 1) Composites of natural rubber latex (NRL)-portland cement mould were prepared as two separate parts. The stabilized natural rubber latex (NRL) with hydroxy ethyl cellulose (HEC) as stabilizer and a delayed-action coacervant (sodium meta silicate) ...
Studied are the mechanical properties of welded joints and heat affected zones of the Kh8N10T steel and OT4 and VT1-2 titanium alloys on welding in Ar+deltaF_6 and Ar+CCl_2F_2 mixtures contributed to a decrease of porosity. Tensile and impact tests of welded joints have revealed that additions of sulfur hexafluoride into argon causes a decrease of impact strength in titanium alloy when the tensile strength does not depend on the composition of a halogen-containing atmosphere. Freon (CCl_2F_2) additions decrease only slightly the impact strength of the investigated alloys.
Cellulose whiskers and microfibrillated cellulose (MFC) were extracted from the rachis of date palm tree and characterized. These cellulosic nanoparticles were used as reinforcing phase to prepare nanocomposite films using latex of natural rubber as matrix. These films were obtained by the casting/evaporation method. The properties of the ensuing nanocomposite films were investigated using differential scanning calorimetry, toluene and water uptake experiments, dynamic mechanical analysis and tensile tests. The stiffness of the natural rubber was significantly increased above its glass-rubber transition temperature upon nanoparticles addition. The reinforcing effect was shown to be higher for nanocomposites with MFC compared to whiskers. It was ascribed to the higher aspect ratio and possi...
Differential Scanning Calorimetry (DSC) is employed to study the changes in enthalpy of natural rubber latex samples when heated under a controlled temperature program. It is found that the mass normalized areas of the DSC curves between room temperature and 170??C for different latex samples are inversely proportional to the dry rubber content (DRC) of the samples, measured following the weighing and drying method. The changes in total enthalpy of the samples in this temperature range are interpreted as due to the variations in the quantity of water present in the samples. The measurements have been repeated by diluting selected samples with known quantities of water, and it is found that the normalized areas of the DSC curves are directly proportional to the amount of water added to the ...
BackgroundThe aim of this report was to describe duodenal obstruction caused by a rubber foreign body in a cow.Case PresentationThe clinical, biochemical...Full Text Available
added to provide resistance to UV degradation, and vulcanization control. ...Sulphur is used to vulcanize the rubber ...additives and solvents age resistors, processing aids, accelerators, vulcanizing agents, softeners and fillers
A novel reactor combining a flame-deposited nanostructured titanium dioxide film and a set of embedded ceramic electrodes was designed, developed and tested for degradation of methyl tert-butyl ether (MTBE) in water. On applying a voltage to the ceramic electrodes, a surface coro...
Silicone-rubber washers function as damping and articulating elements in cast-aluminum spacers that separate bundle subconductors in each phase of extra-high-voltage transmission lines. Spacer/dampers are located every 3 ft. along transmission lines on Canada's first operational 500 and 735 kV system.
The conditions for the production of activated charcoal having a decolorization power (DP) of less than 160 mL/g for methylene blue solutions from the wood of rubber plants were activation temperature of 1000 degrees, rentention time of 30 minutes, and steam-char-ratio of approximately 1.7. The installation of a side-burner around the rotary kiln to decrease the temperature gradient increased the DP of the activated charcoal to 190-200 mL/g without a decrease in yield.
recycling of waste polypropylene (WPP) and waste rubber (WR) originated from rejected worn-out tires present very important problem due to their huge amount and their negative impact on environment. many communities in the world are struggling with this problem of how to manage waste disposal, in order to eliminate or reduce waste rubber from the environment and to reduce costs of some rubber and polypropylene articles. trials to reuse waste rubber and waste polypropylene, have encountered some difficulties.such two substrate polymers differ from each other in nature, since waste polypropylene is thermoplastic while waste rubber exists in thermosetting state. accordingly, the study and use of their mixtures should be very interesting.the aim of this work is to modify the physical and chemical properties of WR and WPP each in the form of powder (120,80 mech size), through a trial to ...
Radiation-and-thermal-combined degradation of ethylene-propylene rubber (EP rubber) and chlorosulfonated polyethylene (CSM) as cable insulating and jacketing materials were evaluated by accelerated aging tests and a method to assess the lifetime of these materials under practical application was studied. EP rubber and CSM of experimental formulation were degraded at accelerated rates, that are 50 [approx] 1000 times the degradation rate under a standard condition (1Gy/h, 50degC). The degradation was investigated by measuring the tensile properties. In the accelerated aging tests, rates of elongation decrease owing to degradation for both EP rubber and CSM were in proportion to increase in accelerated rate. Behaviors of elongation changes showed little difference with accelerated rate. EP rubber lifetime estimated from sequential aging test had a tendency to extend beyond that from ...
Radiation-and-thermal-combined degradation of ethylene-propylene rubber (EP rubber) and chlorosulfonated polyethylene (CSM) as cable insulating and jacketing materials were evaluated by accelerated aging tests and a method to assess the lifetime of these materials under practical application was studied. EP rubber and CSM of experimental formulation were degraded at accelerated rates, that are 50 #approx# 1000 times the degradation rate under a standard condition (1Gy/h, 50degC). The degradation was investigated by measuring the tensile properties. In the accelerated aging tests, rates of elongation decrease owing to degradation for both EP rubber and CSM were in proportion to increase in accelerated rate. Behaviors of elongation changes showed little difference with accelerated rate. EP rubber lifetime estimated from sequential aging test had a tendency to extend beyond that from ...
The methodology of the drip procedure of the Standard Test Method for Evaluating the Influence of Thermal Insulation on External Stress Corrosion Cracking Tendency of Austenitic Stainless Steel (ASTM C 692-95a) was used to research the effect of halogens and inhibitors on the external stress corrosion cracking (ESCC) of Type 304 stainless steel as it applies to the insulation industry. Simulated insulation extraction solutions were made with pure chemical reagents for the halogens and inhibitors. The results indicated that sodium silicate compounds that were higher in sodium were more effective for preventing chloride-induced ESCC in Type 304 austenitic stainless steel. Potassium silicate was not as effective as sodium silicate. Fluoride, bromide, and iodide may cause ESCC but they were much less active than chloride and could be effectively inhibited by sodium silicate compound. The addition of fluoride ions to the chloride/sodium silicate ...
Nylon copolymer (PA6, 66) and ethylene propylene diene (EPDM) blends with and without compatibilizer were prepared by melt mixing using Brabender Plasticorder. The thermal stability of nylon copolymer (PA6, 66)/ethylene propylene diene rubber (EPDM) blends was studied using thermogravimetric analysis (TGA). The morphology of the blends was investigated using scanning electron microscopy (SEM). In this work, the effects of blend ratio and compatibilisation on thermal stability and crystallinity were investigated. The incorporation of EPDM rubber was found to improve the thermal stability of nylon copolymer. The kinetic parameters of the degradation process were also studied. A good correlation was observed between the thermal properties and phase morphology of the blends. By applying Coats ...
Abstract This study was undertaken over a 10-month period under environmental conditions within the state of Mato Grosso, Brazil, to evaluate the causes of variation in the technological and thermal properties of raw natural rubber (NR) from different clones of Hevea brasiliensis (GT 1, PR 255, FX 3864, and RRIM 600). These clones were chosen to represent good clones available in Brazil. The technological properties of raw NR were evaluated in terms of their dry rubber content (DRC), Wallace plasticity, plasticity retention index (PRI), and Mooney viscosity. The thermal performance was evaluated with the thermogravimetry (TG)/differential thermogravimetry (DTG) technique. There were significant variations (p < 0.01 and p < 0.05) between clones and tappings for all technological properties,...
More than sixty base-isolated buildings have been built in Japan. A number of base-isolation systems were considered in our research, which was intended to establish the effectiveness of base-isolation systems. We conducted research on silicone rubber bearings. Generally, silicone rubber is durable and its characteristics are not dependent on the temperature within the relevant design range. The first part of the report covers material and elements testing. After the bearings were installed in the building, we performed forced vibration tests in both the horizontal and vertical directions. These test results form the next section. After several experiments, we carried out earthquake observations. We report on the effectiveness of the system in reducing response acceleration during a small displacement. This system was installed in the building in March 1992
The research and development of a new type of high damping rubber damper for high rise buildings/structures to mitigate earthquake or wind-induced structural response is described in this paper. The static tests were carried out to investigate restoring force characteristics using scale model of high damping rubber damper. The repetitive tests and the temperature dependency tests were carried out to investigate variance of performance of energy absorption. It is confirmed that the damping force characteristics of the damper can be considered as that of linear viscous damping and the damper sufficiently dissipates energy for vibrations of mm order to that of generating 200% shear strain. The design methods, based on assuming linear viscous damping for the damper, has been developed. The designed values such as stiffness and damping coefficient of the damper agree well with the experimental results. (author)
Samples of two seawater farmed fish (crimson snapper (Lutjanus erythopterus) and snubnose pompano (Trachinotus blochii)), water, air, sediment, fish feed, macroalgae and phytoplankton were collected from two estuarine bays (Daya Bay and Hailing Bay) in South China. The concentrations of persistent halogenated compounds (PHCs) including polybrominated diphenyl ethers (PBDEs), organochlorine pesticides and polychlorinated biphenyls (PCBs) varied widely with the different sample matrices under investigation. The compositional patterns in fish, fish feed, macroalgae and phytoplankton, as well as the good correlations between the abundances of p,pprime-DDT and BDE-209 and their metabolites (i.e., p,pprime-DDD and p,pprime-DDE for p,pprime-DDT and BDE-47 for BDE-209) in fish indicated the occurr...
In the present work temperature dependences of heat capacity of carbosilane dendrimers with butyl terminal groups of the third and the fourth generations as well as of the fifth and the sixth generations have been determined first in the range from 6 to 340K and between 6 and 600K, respectively, by precision adiabatic vacuum and dynamic calorimetry. In the above temperature ranges the physical transformations have been detected and their thermodynamic characteristics have been estimated and analyzed. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity C{sub p}{sup o}(T), enthalpy H{sup o}(T)-H{sup o}(0), entropy S{sup o}(T)-S{sup o}(0) and Gibbs function G{sup o}(T)-H{sup o}(T), for the range from T->0 to (340-600)K. Linear dependences of changing the corresponding thermodynamic functions of the dendrimers on their molecular weight and the number of butyl groups on an outer sphere have ...
BackgroundSeveral aromatic amines (AA) could cause bladder cancer and are an occupational hygiene problem in the workplace. However, little is known about the percutaneous absorption...Full Text Available
The possible contribution to urinary mutagenicity of occupational exposures in the rubber industry was studied by assaying the urine concentrates of 72 workmen (44 smokers) employed in a tyre plant....Full Text Available
In the second part of this paper the author concludes his examination of the application of thermoplastic materials and also considers alumina ceramics, cast basalt and glass, rubbers, resins and wear-resistant steels
The purpose of this study is to determine the suitability of producing agro-fiber reinforced plastic composite (agro-FRPC) from rubber wood fiber blended in polypropylene matrix. The effects of varying fiber dimension and fiber content on the physical and mechanical properties of the composite were evaluated to provide an insight into the fiber matrix adhesion. The effects of reactive additives on the physical and mechanical properties of the composite were evaluated which provides the insight on the reinforcement of the composite. Rubber wood fiber used in this study is currently being used in the manufacturing of medium density fiber (MDF) board. Two sizes of rubber wood fiber were used i.e. 0.5-1.0 mm and 1.0-2.0 mm. Homopolymer polypropylene of MFI 14.0 was used as a matrix. The irradiation work was carried out using electron beam accelerator, 3.0 MeV, 3.0 mA. Various types of reactive additives (RA) with ...
The dielectrical properties of organosilicon sealants have been studied in the wide range of temperatures in the low and radio frequencies range. The effect of thermal treatment and #gamma#-irradiation on these properties is discussed.
Apr 19, 1996 ... I learned that unlike most nuclear submarines that have 3 or more access routes, the NR-1 has just one hatch. At shallow depths, a rubber ...
...Automatic emergency-parking brakes. (a) Except for personnel carriers, rubber-tired, self-propelled electric haulage equipment used in the active workings of underground coal mines shall be equipped with automatic emergency-parking...
...persons from danger of runaway haulage equipment. (f) An audible warning...within 300 feet of preceding haulage equipment, except trailing locomotives...provided for all rubber-tired haulage equipment where such equipment is...
Rubber lining is used as a corrosion protection material in European flue gas desulfurization plants, for scrubbers, tanks, pipe systems, etc. Although these rubber linings can last more than 15 years, relining still is necessary. The difficulty of shutting down power station units requires that the time scale of this replacement be kept to a minimum. High-pressure water systems have proven successful as an efficient method for removal of the old lining. The working steps and time scale are demonstrated for one such relining case.
Methylmethacrylate polymerisation in the presence of 4 wt% butadiene-acrylonitrile rubber was carried out at fixed dose-rate and temperature. The effect of irradiation was investigated with respect to the mechanical and dynamic-mechanical properties in the solid state. A general increase of the 'compatibilisation' on irradiation is obtained. In fact both rubber and polymethylmethacrylate glass transition temperatures, determined through dynamic-mechanical analysis, reveal the presence of strong interactions between the components. Furthermore an improvement of the mechanical tensile properties of the blends is observed when irradiation is continued after polymerisation, at least until a certain absorbed dose.
The integrity of helium circulation loop flanged joints has been attracting recent attention as a design problem, in the development of high-temperature facilities incorporating helium loops (e.g., the VRG-50 pilot nuclear facility). Elevated temperatures and pressures, and the radiation environment, impose additional requirements on sealant materials. This applies first and foremost to rubber seals, which have found widespread favor on account of its excellent elasticity, its ability to spontaneously conform to possible changes in the clearance in the seal assembly, and the low compressive stresses developed in the flange joint assembly.
Wood-polymer composites (WPC) have been prepared of pinewood with different monomers using Gamma radiation: acrylamide, butyl acrylate, butyl methacrylate, styrene, acrylonitrile, and polyester. The polymer loading was determined as a function of monomer concentration and absorbed dose. The data show that polymer loading increases by increasing the monomer concentration. In two cases, BMA and polyester, the polymer loading decreases at high concentrations. This can be explained by the increase of the viscosity. Thus the diffusion of the compound into bulk would be slower. The absorbed dose seems to play a positive role in enhancing the polymer loading by increasing the dose. The mechanical properties, tensile and compression strength, have been improved in the most cases for all monomer concentrations or absorbed doses. Using polyester there was no improvement in the mechanical properties, and using acrylamide the improvement was at high ...
This study compares two series of solvents for application in aluminum electrolytic capacitors: ethylene glycol (EG) and water mixtures, and ethylene glycol and 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF4) ionic liquid (IL) mixtures. Electrochemical impedance spectroscopy and cyclic voltammetry were carried out with a previously anodized aluminum disk electrode. Comparative measurements of solution resistance, polarization resistance, AC capacitance, and passive current were made. The results show that EG?IL mixtures with low amounts of IL (10% IL?90% EG v/v) have a low solution resistance. Low values of solution resistance, high values of polarization resistance, small passive current, and uniform capacitance of anodized aluminum in EG?IL mixtures are favorable properties of ...
The acid corrosion inhibition process of mild steel in 1M HCl by 1-butyl-3-methylimidazolium chlorides (BMIC) and 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO4) has been investigated using electrochemical impedance, potentiodynamic polarization and weight loss measurements. Potentiodynamic polarization studies indicate the studied inhibitors are mixed type inhibitors. For both inhibitors, the inhibition efficiency increased with increase in the concentration of the inhibitor and the effectiveness of the two inhibitors are in the order [BMIM]HSO4>BMIC. The adsorption of the inhibitors on mild steel surface obeyed the Langmuirs adsorption isotherm. The effect of temperature on the corrosion behavior in the presence of 5x10-3M of inhibitors was studied in the temperature range of 3...
A composition and method for encapsulating a photovoltaic device which minimizes discoloration of the encapsulant. The composition includes an ethylene-vinyl acetate encapsulant, a curing agent, an optional ultraviolet light stabilizer, and/or an optional antioxidant. The curing agent is preferably 1,1-di-(t-butylperoxy)-3,3,5-trimethylcyclohexane; the ultraviolet light stabilizer is bis-(N-octyloxy-tetramethyl) piperidinyl sebacate and the antioxidant is selected from the group consisting of tris (2,4-di-tert-butylphenyl) phosphite, tetrakis methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate) methane, octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, and 2,2'-ethylidene bis(4,6-di-t-butylphenyl) fluorophosponite. The composition is applied to a solar cell then cured. The cured product contains a minimal concentration of curing-generated chromophores and resists UV-induced degradation.
DescriptionMeasurements of halocarbons (CFCs and other halogen-containing compounds) in the tropical stratosphere will be made from a long duration MIR balloon. The balloon and instruments are capable of flying for three or more weeks in which time they will circum-navigate the globe. As the balloon rises each morning and falls each evening, measurements of halocarbons will be made every few hundred meters between about 20 and 30 km. In total it is hoped that over 40 such vertical profiles will be obtained [continued...
Halide complexes of astatine cations At"+ and AtO"+ were prepared and their rate of migration was measured. The complexes are of the type AtX_2"- and AtOX_2"- (X = Cl"-, Br"-, I"-). The bromo complexes, AtBr_2"- and AtOBr_2"-, have a higher stability than the chloro complexes. The hydrolysis in weakly alkaline solution of AtX_2"- resulted At"-, and that of AtOX_2"- AtO_2"-. (author).
Partial Contents: Ternary Compounds; Granular Superconductors; Superconductivity in (SN)x and its Halogen Derivative (SNBr0.4)x; Studies of cuCl at Elevated Pressures; Superconducting Properties of Hydride Systems; Thin Film Superconducting Materials Research; Synthesis of Superconducting Nb3Si using High Pressures; Synthesis of Unstable A-15 Compounds by Epitaxial Recrystallization of Ion Implanted Layers; and Sputtering of Nb3Si.
Negative ions have attractive features as drivers for inertial confinement fusion, because they will avoid electron cloud effects, and could be efficiently photodetached to neutrals after the final focus, which could also be beneficial in heating warm dense matter targets. The halogens have large electron affinities, and thus should be able to produce high current densities of relatively robust negative ions. Recent experiments comparing chlorine beams to argon beams using the same source, extraction optics, and diagnostics have demonstrated that Cl"- beams can be produced with similar emittance to Ar"+ beams, and with about 34 the current density from the same configuration. The observed effective beam temperature of about 13eV, and the similarity of current densities show that negative halogen beams can meet the current density and emittance requirements of heavy ion fusion. The near equivalence of the Cl"- and Cl"++Cl_2"+ current densities ...
The halogenated benzimidazoles BDCRB (2-bromo-5,6-dichloro-1-β-d-riborfuranosyl benzimidazole riboside) and TCRB (2,5,6-trichloro-1-β-d-riborfuranosyl benzimidazole...Full Text Available
Short review of works on astatine chemistry carried out by authors for the last thirty years are done. Discovery of single-charged cation stable in aqueous solutions is predominant attainment of authors in the branch of inorganic chemistry. The first successful synthesis of heptavalent astatine compounds is a new and significant result of the last years. New direction in the chemistry of the fifth halogen is organic chemistry of astatine
Diethyl phthalate (DEP) and di-n-butyl phthalate (DnBP) are used extensively in personal care products, including fragrances (DEP) and nail polish (DnBP). Between May 2003 and...Full Text Available
Calorimetry testing of Tri-n-butyl phosphate (TBP) saturated with strong nitric acid was performed to determine the relationship between vent size and pressure buildup in the event of a runaway reaction. These experiments show that runaway can occur in an open system, but that even when runaway is induced in the TBP/HN0{sub 3} system, dangerous pressure buildup will be prevented with practical vent size.
The complexing of paramagnetic salts of molybdenum and tungsten with tri-tert-butylphenyl ester of 1,2-naphthoquinone-diazide-(2)-5-sulfochloride is studied by PMR and EPR methods. From the changes of half-widths of lines in PMR spectra and analysis of g-factor in EPR spectra, the kinetic and thermodynamic parameters of the complexing are determined, and the composition of the complexes formed is established, and the schemes of their formation are suggested.
A primary and basic question prevails in the methanol industry - What will be the global demand for methanol, for the expanded production of methyl tertiary butyl ether (MTBE), during the next few years This article attempts to answer the question by discussing the global market; supply and demand factors; the market in North America, Western Europe, Far East and Asia, South America, and other regions; and the uncertainties that remain.
N-Hydroxy-N′-(4-n-butyl-2-methylphenyl)formamidine (HET0016) is a potent inhibitor of 20-hydroxyeicosatetraenoic acid (20-HETE) formation by specific cytochrome P450 (CYP) isoforms....Full Text Available
The International Atomic Energy Agency has initiated a co-ordinated research programme on implementation of base-isolation for nuclear structures. This paper discusses two areas relevant to modelling elastomeric base-isolators. These are the use of simplified models to predict the response of isolated structures to earthquake inputs and finite element analysis for calculating the stress distributions within the isolators. In the former, a curvilinear hysteretic model of the high damping natural rubber able to accommodate the stiffening of the rubber at large shear deflections is presented. Its predictions of structural accelerations and bearing displacement produced by design earthquakes and those above the design level are compared with those using a linear spring and dashpot model. A comparison has been made between two finite element analyses using MARC and ABAQUS of the force-deformation behaviour of a single disc of ...
In the present study a partial replacement of aggregate with two different ratios of waste rubber (5%, 10%) with the addition of a constant ratio of rice husk ash (RHA), 5% was carried out. The hardened cement mortar used the optimum water of consistency. The specimens were molded into 1 inch cubic moulds .The specimens were first cured for 24 hours, at 100% relative humidity and then cured under tap water for 3, 7 and 28 days followed by irradiation at different doses of gamma irradiation namely 5 and 10 kGy. The physico-chemical and mechanical properties such as compressive strength, total porosity and bulk density were studied for the three types of specimens. The results showed that the values of the compressive strength, bulk density and chemically combined water of the blended cement mortar paste (OPC-RHA) increase ,while blended cement mortar paste with 5% RHA and 5, 10% waste rubber decrease. The results were confirmed by scanning ...
Effect of radiation dose and carbon nanotubes (CNT) on the mechanical properties of standard Malaysian rubber (SMR) was investigated in this study. SMR nanocomposites containing 1-7 phr CNT were prepared using the solvent casting method and the nanocomposites were radiated at doses of 50-200 kGy. The change in mechanical properties, especially, tensile strength (Ts), elongation at break (Eb), hardness and tensile modulus at 100% elongation (M{sub 100}) were studied as a function of radiation dose. The structure and morphology of reinforced natural rubber was investigated by FESEM, TEM and AFM in order to gain further evidence on the radiation-induced crosslinking. It was found that the Ts, M{sub 100} and the hardness of the SMR/CNT nanocomposites significantly increased with radiation dose; the elongation at break exhibited an increase up to 100 kGy, and a downward trend thereafter. Results on gel fraction further confirmed the crosslinking of ...
The effect of ammonia treatment in field natural rubber (NR) latex with different storage period time on the properties of concentrated NR latex and stability of skim latex was investigated. Fresh NR latex was treated with various ammonia contents such as 0.35, 0.60 and 0.80% w/w, and then they were centrifuged to get the concentrated NR latex with 60% dry rubber content (DRC) containing 0.16, 0.18 and 0.25% w/w, respectively and skim NR latex with roughly 5% DRC containing 0.42, 0.60 and 0.80% w/w, respectively. The effect of storage times with ?0, 15, 30 and 45 days for concentrated NR latex with different ammonia contents on their properties such as alkalinity, magnesium content and viscosity was observed. It was found that generally, magnesium content in field NR latex and latex...
Low molecular weight epoxy resin based on diglycidyl ether of bisphenol A was synthesized and mixed at constant percentages with natural rubber. The rubber epoxy system was cured with various types of curing agents such as ethylene diamine, maleic anhydride as well as the prepared resole phenol formaldehyde. A study of the photo-induced crosslinking of the prepared elastic adhesives and film samples was carried out by exposure to ultraviolet lamp (300 w) for 2 weeks at 20 deg. C. Samples containing ethylene diamine were cured at 25 + - 1 deg. C. for 24 h while samples containing maleic anhydride or resole phenol formaldehyde resins were thermally cured at 150-170 deg. C. for 10 min. Cured adhesive compositions were tested mechanically and physically and evaluated as wood adhesives. While hardness, chemical resistance as well as heat stability of the prepared cured film sample were investigated. The obtained data indicate that the highest epoxy ...
Several series of pyrimidine nucleosides were evaluated as part of a larger program to develop non-invasive brain imaging agents. The interaction of these antitumor/antiviral nucleosides with an NBMPR-sensitive murine erythroctye nucleoside transporter was evaluated by determining their inhibitory effect (K_i) on zero-trans influx of thymidine. Within each series of compounds, which had F, Cl, Br or I as halogen substituents, an increase in size of the halogen atom or a decrease in electronegativity decreased affinity for the transporter. Partition coefficients (P) of these pyrimidine nucleosides were measured to determine their potential to diffuse across the blood-brain-barrier (BBB). Most of the pyrimidine nucleosides had lower P values (log P < 0.9), and were considered to be poor candidates for simple diffusion across the BBB, although an active BBB transport mechanism for some nucleosides could be operative. For a given series, it was ...
'The interactions of carbon tetrachloride with strongly basic oxides and hydroxides have been studied by several techniques in order to understand the surface reactions and the subsequent bulk reactions that result in the destruction of the chlorinated hydrocarbon. Emphasis has been placed on understanding the surface phases, as well as the bulk phases, that are present during these transformations. As a result of the study with barium oxide, a reaction cycle has been demonstrated that may have practical significance in the removal of chlorinated hydrocarbons.'
This short communication aims to update the review of non-nitro radiation sensitizers (Shenoy and Singh 1985) and correct omissions. Work is mentioned and bibliography given for studied of cis-platinum, potassium permanganate, cobalt hexammine, sodium bromide, dimethylsulphoxide, zinc and copper ions, organic nitroxyl free radicals (TAN,TMPN and NPPN + PNAP), halogenated pyrimidines, organic and inorganic iodine containing compounds, diacetyl, acetone and acetophenone, rho-hydrobenzoic acid and its esters, pentobarbitone and secobarbitone, heparin and 9-anilinoacridines, dehydropiandosterone and paraquat. (U.K.).
A chemically assisted micro-beam etching system for 3D microanalysis was designed. Using chemically assisted ion beam etching (CAIBE) method with FIB shave-off scanning, about several hundred micrometers clean cross-section will be acquired in a few hours. We use focused ion beam (FIB) and electron beam (EB) as micro-beams, halogen or halide mainly as reactive gases. The apparatus was manufactured based on this concept. We found that the FIB, Q-MS and SED worked as expected. The instrumentation has been completed.
By comparison of standard entropies theoretically calculated and determined from gas-chromatographic data for 40 halo-aliphatic and halo-aromatic compounds 8 organic iodine compounds among them, adsorbed on graphitized thermal carbon black it was found that in all the cases the molecular model of ideal two-dimensional gas is a sufficiently good approximation. It was shown that for a number of systems the agreement can be improved if the vibrations of the center of molecular mass relative to the surface are taken into account
In this article, we describe a method used to prepare an in situ sodium-activated, organomodified bentonite clay/styrene-butadiene rubber nanocomposite master batch via a latex blending technique. The clay master batch was used for compound formulation. Octadecyl amine was used as an organic intercalate. The clay was purchased from local suppliers and was very cheap. Sodium chloride was used for in situ activation of the clay. The wide-angle X-ray diffraction data indicated that the in situ sodium activation helped to increase the intergallery distance from 1.28 to 1.88 nm. A transmission electron micrograph indicated intercalation and partial exfoliation. The thermal properties were relatively better in the case of the sodium-activated, organomodified bentonite-clay-containing compound. A...
This paper presents a detailed characterization and rheometric property study of in-situ sodium activated, organomodified bentonite clay - styrene-butadiene rubber (SBR) nanocomposite. It was found that around 10phr loading was the optimum level for maximum effect of the organo clay. The WAXD data indicated that at higher loading there was formation of agglomerations in the matrix. It was found that organo clay compound exhibited lower maximum torque in comparison to equivalent amount of carbon black loaded compound. The nanocomposites were also used for partial replacement of N330 carbon black in a highly black loaded compound. Part replacement of the carbon black with nano-clay reduced the maximum rheometric torque in comparison to the control compound. Detail study revealed that with sl...
Natural rubber (NR) and its derivatives as renewable and biodegradable materials have attracted considerable attention because of the serious pollution problems caused by synthetic materials and a shortage of resources. A new semi-interpenetrating polymer network (semi-IPN) based on epoxidised natural rubber and polyvinyl alcohol containing maleic acid as a crosslinking reagent was synthesized and characterized by FTIR, XRD, SEM, swelling ratio in both distilled water and toluene, and mechanical properties. The curing time and dose of maleic acid were varied from 10 to 60min, and from 10 to 60% (w/w), respectively. An IR spectroscopic study indicated the presence of an ester linkage at 1730cm-1 in maleic acid crosslinked with PVA in semi-IPN films. In addition, the crystalline content of P...
A solid layer artificial pollution test was carried out to study the pollution performance of a new type of hybrid station post insulator used in suspension and tensile high voltage transmission lines. The structure of the separated silicone rubber shed and porcelain core hybrid insulator was shown. The new insulator showed excellent pollution performance under both HVAC and HVDC conditions. It also exhibited excellent aging performance in artificial aging tests. The mechanical strength of the hybrid insulator was also better than normal composite insulators. Another advantage revealed was the fact that separated silicone rubber sheds and porcelain core hybrid post insulators are easier to manufacture than normal porcelain post insulators and other hybrid insulators. 5 refs., 6 tabs., 1 fig.
In many drug dispensing devices, such as syringes and inhalers, an elatomeric gasket is used to prevent the formulation from leaking from the chamber. During device actuation, the seal is subjected to friction, which in turn causes its deformation and can cause unintentional leakage, thus dose variability. Additionally, friction of seal is responsible for a host of potential problems such undue effort required for actuation and potential wear. The mechanism of friction generation in the seal conjunction is complex, arising from adhesion of rubber in contact with the moving interface, viscous action of a thin film of fluid and deformation of seal asperities. Therefore, the first step in understanding the conjunctional behaviour of rubber seals is a fundamental study of mechanisms of frictio...
This study describes the effect of treatment of Bis(3-triethoxysilyl propyl)tetrasulfane (silane coupling agent, Si69, TESPT) on in situ sodium activated, organo modified bentonite clay - styrene butadiene rubber (SBR) nanocomposite. transmission electron microscopy and Wide angle X-ray diffraction indicated the intercalation as well as partial exfoliation in both the organoclay and silane treated organoclay compound. It was found that about 5% of silane with respect to clay was the optimum dose for the treatment. Around 15% improvement in tensile and tear strength was observed due to silane treatment. Silane treated organoclay exhibited substantial improvement of the fatigue life, compression set, and rebound property. A detailed study of physical property was carried out. A comparison wi...
We have demonstrated in this work (1) that methane is readily activated at mild conditions (100{degree}C, 1 torr) over a relatively noble metal, Pd. This was observed using a stepped and kinked Pd(679) crystal (1), and other crystal faces are now being investigated to establish whether the cracking of the C-H bond of methane on Pd is structure sensitive or structure insensitive. Oxygen chemisorption is extremely structure sensitive: weakly bonded, highly reactive oxygen overlayers form on Pd(100) surface (2), while strongly bonded, moderately reactive oxygen overlayers form on Pd(111) and Pd(679). Reaction of the weakly bonded oxygen with surface carbide gives rise to CO{sub 2} over clean Pd(100) but to CO over halogen-doped Pd(100) (3--5). The effect of halogens is primarily ensemble-controlling, or oxygen-supply restricting, but long range influence of surface Cl on the strength of the Pd-O bond has also been observed (3). Because the overall ...
We have demonstrated in this work (1) that methane is readily activated at mild conditions (100[degree]C, 1 torr) over a relatively noble metal, Pd. This was observed using a stepped and kinked Pd(679) crystal (1), and other crystal faces are now being investigated to establish whether the cracking of the C-H bond of methane on Pd is structure sensitive or structure insensitive. Oxygen chemisorption is extremely structure sensitive: weakly bonded, highly reactive oxygen overlayers form on Pd(100) surface (2), while strongly bonded, moderately reactive oxygen overlayers form on Pd(111) and Pd(679). Reaction of the weakly bonded oxygen with surface carbide gives rise to CO[sub 2] over clean Pd(100) but to CO over halogen-doped Pd(100) (3--5). The effect of halogens is primarily ensemble-controlling, or oxygen-supply restricting, but long range influence of surface Cl on the strength of the Pd-O bond has also been observed (3). Because the overall ...
Conditions for radiation induced grafting with butyl acrylate dispersed in water emulsion onto chrome-tanned pig skins have been worked out for #gamma#-rays and electron beam irradiations. The highest yield of grafting was observed at monomer concentration approximately 25% (w/w), dose equal to 25 kGy and dose rate not exceeding 10 MGy/h. At these conditions the yield of grafting attained a value approximately 25% and content of homopolymer in the leather amounted to 6%. The efficiency of monomer to polymer conversion decreases when the concentration of monomer in emulsion and dose rate increases. Yield of homopolymer is independent of the dose rate. An explanation of the observed relations has been proposed. The physical and used properties of grafted leathers were tested. Radiation processed leathers were found superior to samples finished by traditional methods. One has to point to better tolerance against chemical cleaning and reduced water take-up without loss ...
Proteomic changes in proteins secreted by human hepatocellular carcinomas (HepG2) cells exposed to butyl benzyl phthalate (BBP) were evaluated. HepG2 cells were treated with three different concentrations of BBP (0, 10, or 25 ?M) for 24 or 48 h. Following incubation, the cells were subjected to proteomic analysis using two different pI ranges (4-7 and 6-9) and large-size two-dimensional gel electrophoresis. Results showed resolution of a total of 2776 protein spots. Of these, 29, including 19 upregulated and 10 downregulated proteins, were identified by electrospray ionization-mass spectrometry-mass spectrometry (ESI-MS/MS). Among these, the identities of cystatin C, Rho guanine nucleotide dissociation inhibitor, gelsolin, DEK protein, Raf kinase inhibitory protein, triose phosphate ...
The goal of this work is to study the effect of the aqueous medium pH on the two-phase equilibrium behaviour of the aqueous {1-butyl-3-methylimidazolium bromide ([C4mim]Br)+potassium citrate} system in order to obtain further information about the salting-out effect produced by the addition of a kosmotropic salt to an aqueous solution of a hydrophilic ionic liquid (IL). For this purpose the phase diagrams and the liquid-liquid equilibrium (LLE) data of the {[C4mim]Br+potassium citrate} aqueous two-phase system (ATPS) were determined experimentally at different pH values. Four medium pH values (5.00, 6.00, 7.00 and 8.00) were assayed at T=298.15K. The effect of pH on the ATPS-promoting capability of citrate anions in the aqueous [C4mim]Br solutions was explained based on the structural hydr...
The effect of butylated hydroxytoluene (BHT) pretreatment (0.5% in the diet for 10 days) on the excretion, tissue distribution and DNA binding of orally administered (/sup 14/C)aflatoxin B1 (AFB1) was determined in male Fischer F344 rats. The amount of radioactivity excreted in the urine and feces by 24 hr was higher in BHT-treated rats than in controls. Treatment with BHT enhanced the excretion of water-soluble metabolites in the urine and in the large intestines plus feces at the earlier sampling times. The amount of radioactivity bound to hepatic nuclear DNA was six times less in the BHT-pretreated rats than in controls 6 hr after administration of the isotope. The half-lives of (/sup 14/C)DNA in the rat liver were 30 and 46 hr for control and BHT-pretreated rats, respectively. These results indicate that BHT pretreatment may protect the animal from the carcinogenic effects of AFB1 by enhancing the detoxification and excretion of the mycotoxin.
The acid corrosion inhibition process of mild steel in 1 M HCl by 1-butyl-3-methylimidazolium chlorides (BMIC) and 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO{sub 4}) has been investigated using electrochemical impedance, potentiodynamic polarization and weight loss measurements. Potentiodynamic polarization studies indicate the studied inhibitors are mixed type inhibitors. For both inhibitors, the inhibition efficiency increased with increase in the concentration of the inhibitor and the effectiveness of the two inhibitors are in the order [BMIM]HSO{sub 4} > BMIC. The adsorption of the inhibitors on mild steel surface obeyed the Langmuir's adsorption isotherm. The effect of temperature on the corrosion behavior in the presence of 5 x 10{sup -3} M of inhibitors was studied in the temperature range of 303-333 K. The associated activation energy of corrosion and other thermodynamic parameters such as enthalpy of ...
The acid corrosion inhibition process of mild steel in 1 M HCl by 1-butyl-3-methylimidazolium chlorides (BMIC) and 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO_4) has been investigated using electrochemical impedance, potentiodynamic polarization and weight loss measurements. Potentiodynamic polarization studies indicate the studied inhibitors are mixed type inhibitors. For both inhibitors, the inhibition efficiency increased with increase in the concentration of the inhibitor and the effectiveness of the two inhibitors are in the order [BMIM]HSO_4 > BMIC. The adsorption of the inhibitors on mild steel surface obeyed the Langmuir's adsorption isotherm. The effect of temperature on the corrosion behavior in the presence of 5 x 10"-"3 M of inhibitors was studied in the temperature range of 303-333 K. The associated activation energy of corrosion and other thermodynamic parameters such as enthalpy of activation (#DELTA#H), entropy of ...
A preliminary chemical characterization is presented of phosphate-free aminolipids isolation from Chlorobium limicola f. thiosulfatophilum. The lipid contains no phosphorus, glycerol, sugar, ornithine, or lysine. Ultraviolet absorption and fluorescence spectra indicate that the amino moiety of the lipid is an aromatic heterocyclic compound. Infrared spectra indicate that the lipid is a secondary or tertiary amide, and gas chromatograhic analysis of the hydrolyzed lipid shows that for each 1100 g of lipid, 1 mol of myristic acid (C/sub 14:0/) is linked in an amide bond. Acid hydrolysis of the lipid yields two fluorescent substances, A (ninhydrine positive) and B (negative), in addition to myristic acid. Proton nuclear magnetic resonance (NMR) studies indicate that substance A contains a butyl groups attached to a conjugated ring carbon, two equivalent ethyl groups attached to one or two nitrogen atoms, and two downfield protons (8.4 ppm), perhaps attached to a ring ...
Carrier-free "8"8Y radioisotope, which has the longest half life (T=106.6 d) of yttrium radioisotopes and is a #gamma#-ray emitter, was obtained by proton irradiation of strontium, followed by cooling for one month. Then, "8"8Y was purified by precipitating strontium as strontium nitrate and extracting yttrium with tri-n-butyl phosphate (TBP). The decontamination factor of strontium to yttrium was more than 4x10"3 and chemically pure yttrium radioisotope was obtained. (author) 6 refs.
Mechanical properties, flow characteristics and chemical resistance of polycarbonate (PC)/polybutylene terephthalate (PBT)/impact modifier (IM) blends were investigated over the various composition ranges of PC and PBT. Mechanical properties of the PC/PBT/IM blends for different IMs, butadiene based IM and butyl acrylate based IM, were studies for various compositions of the IMs. Impact strength at low temperature was also observed. For the study of chemical resistance of the PC/PBT/IM blends, the blends were dipped in organic solvent, thinner, and then variations of mechanical properties were analyzed. Tensile and flexural strengths were increased linearly and heat distortion temperature (HDT) also increased as PC content in the blends increased. Impact strength increased drastically as PC content increased up to 50 wt% and stayed stable value. Flowability decreased as PC content increased. impact strengths of the blend were various for different IMs. ...
The polymer industry is a young industry that has undergone tremendous growth and change over the last sixty years. Many important discoveries in polymer science have been accidental. Most of the learning has been by trial and error and most of the understanding is still basically empirical--make a polymer material or compound and then put it to the test to study what it is and how it performs. This article provides an overview of what polymers and polymer compounds are, why they behave as they do, and it discusses several examples of failures of rubber and plastic components.
During the first and second quarters of 1994 air samples were collected and analyzed from 54 air particulate/halogen sampling stations, 10 noble gas sampling stations and 19 tritiated water vapor sampling stations. Surface water samples were collected and analyzed from 12 open water supply reservoirs, 8 natural springs, 2 wastewater containment ponds and 9 sewage lagoons. Groundwater samples were obtained brom 10 potable and 1 non-potable supply wells, and 8 drinking water consumption points. Ambient radiation levels were measured at 193 locations.
Lead is known to enter substitutionally in divalent state when doped in alkali halides. When irradiated at room temperature these lead centers (Pb"+"+) act as traps for electrons knocked off from the halogen ions and become Pb"+ and Pb"0 (for large doses of irradiation). These changes could be followed in the optical absorption studies. These lead-doped crystals after X-ray irradiation yield a thermoluminescence output smaller than that observed in 'pure' crystals. However, two new glow peaks are observed in additions to those due to F-centers. In KCl : Pb and Kbr : Pb crystals part of the F-center glow preceds the new glow peaks. The new peaks are attributed to the Pb"+ and Pb"0 centers. The glow peak temperatures and trap depths for these peaks an obtained by total-curve fitting method are reported. (author).
This paper introduces the radioactive effluent monitoring systems, measurement and quality control methods used in Daya Bay Nuclear Power Station from its commercial operation in 1994. The main work and experiences for the management of effluent release are discussed and analyzed. The radwaste data appear declining trend and are far blow the annual limit approved by the national Environmental Protection Bureau since 1995. The normalized release (unit GBq/GWa) of 9 years is as follows: liquid nuclides (except tritium) 11.1, liquid tritium 1.91 x 10"4, noble gas 2.03 x 10"4, halogen 0.13, aerosol 7.57 x 10"-"3. For "1"1"0"mAg, the average release from 1998 to 2002 has been reduced to 1/7 of the quantity in 1997
Porcine pancreatic lipase immobilized on celite particles has been employed as a catalyst for the esterification of dodecanol and decanoic acid in a predominantly organic system. Solvent influence on the equilibrium position and on the catalyst activity has been studied using 20 solvents, including aliphatic and aromatic hydrocarbons, ethers, ketones, nitro- and halogenated hydrocarbons, and esters. The equilibrium constant for esterification correlates well with the solubility of water in the organic solvent, which in turn shows a good relationship with a function of Guttman's donor number and the electron pair acceptance index number of the solvent. This may be rationalized in terms of the requirements for solvation of water and of the reactants. The catalyst activity, measured as the initial rate of the esterification reaction, is best correlated as a function of both n-octanol-water partition coefficient (log P) and either the electron pair acceptance index or ...
Biopharmaceutical R&D complexes are major emission sources of volatile organic compounds (VOCs), which may pose potential health risks for staff on site and residents nearby. In this paper health risk assessments were performed for the VOCs in the ambient air of a typical biopharmaceutical R&D complex in China. Results showed halogenated and alkyl compounds were dominant components among 24 major VOCs from 9 selected sampling sites, inside or around the complex. The principal component analysis (PCA) indicated VOCs were generated predominantly from the biopharmaceutical research activities (factor 1 (F1), 71.6%) and traffic vehicles (factor 2 (F2), 15.4%), which were confirmed by contour maps of five selected VOCs (benzene, toluene, chlorobenzene, methylene chloride and n-hexane) simulated...
The change in the concentration of hydrogen peroxide in the course of its decomposition was shown, catalyzed by 0.02 M PbI/sub 2/, 0.03 M CuI, 0.02 M KI, 0.02 M FeSo/sub 4/, 6 M HCl, and 1 M HCL + 2 M H/sub 2/SO/sub 4/ at 25 C. It was suggested that in the process of the catalytic decomposition at the initial stage of the reaction, the formation of an intermediate active species containing positively charged halogen occurs; depending on the oxidative power of the counterion, the relative proportions of the hydrogen peroxide decomposing under the action of either the cation or the anion varied.
Problems relating to electromagnetic compatibility and power quality were discussed, combined with a discussion of the role that consulting engineers can play in resolving them. The need for the consulting engineer to be aware of design specifications of equipment was considered essential. Similarly, the interrelationship between installations using variable speed drives, halogenous lighting systems, capacitor banks, high-voltage power lines, power transformers, etc., and the need for familiarity with the operating characteristics of different types of power systems were stressed as key ingredients to success in ascertaining events and causes of equipment failure or power system problems on the network. The main sources of disturbances, impact of voltage variations, the importance of controlling voltage imbalance, and system protection were summarized. 4 figs.
Charge carrier profiles are measured for boron implanted into silicon (E = 30 keV, dose range 5 x 10"1"5 to 2 x 10"1"6 B/cm"2) after rapid isothermal annealing using halogen lamps. Maximum temperatures between 1000 and 1300 "0C and holding times at T/sub max/ of 5 and 20 s are used for the annealing treatment. In a few additional experiments flash lamp annealing at 1350 "0C (pulse duration 20 ms) is investigated. By comparison of the experimental profiles with computer simulations using the SUPREM II program transient enhanced diffusion of boron could be detected in all investigated cases. Maximum charge carrier concentrations above the equilibrium solubility of boron are observed and are discussed. (author).
In this research, new thin freestanding films of poly(methyl methacrylate) (PMMA)/50% epoxidised natural rubber (ENR 50) were doped with lithium triflate, LiCF3SO3 salt was prepared by a solvent casting method. The incorporation of ENR 50 is found to increase the conductivity of PMMA/LiCF3SO3 by two orders of magnitude at room temperature. The highest conductivity achieved was 5.09x10-5Scm-1 at room temperature when 60% of LiCF3SO3 salt was introduced into the PMMA blend containing 10% ENR 50. The formation of excessive hydrogen bonds and interchain crosslinking limit the performance of the blend at higher concentrations of ENR 50. The ionic conduction mechanisms in PMMA/ENR 50/LiCF3SO3 electrolytes obey the Arrhenius rule in which the ion transport in these materials is thermally assisted...
Strain-induced crystallization of crosslinked natural rubber (NR) and its synthetic analogue, cis-1,4-polyisoprene (IR), both mixed with various amounts of stearic acid (SA), were investigated by time-resolved X-ray diffraction using a powerful synchrotron radiation source and simultaneous mechanical (tensile) measurement. No acceleration or retardation was observed on NR in spite of the increase of SA amount. Even the SA-free IR crystallized upon stretching, and the overall crystallization behavior of IR shifted to the larger strain ratio with increasing SA content. No difference due to the SA was detected in the deformation of crystal lattice by stress for both NR and IR. These results suggested that the extended network chains are effective for the initiation of crystallization upon stretching, while the role of SA is trivial. These behaviors are much different from their crystallization at low temperature by standing, where SA acts as a nucleating agent.
Crude oil-polluted soil (five parts of weathered crude oil per 100 parts of soil; equivalent to 50,000 mg oil kg{sup -}1 soil) samples were slurried in deionised water (300% of the water retention capacity of the soil) and treated with various amounts of natural-rubber processing sludge (nitrogen content 62.15 mgkg{sup -1} and phosphorus contents 8.75 mgkg{sup -1}) in a well-stirred, continuously-aerated tank at 29{sup o}C. Changes in the total hydrocarbon content of the soil sample were determined, using a spectrophotometric technique, as a function of time. The extent of crude oil degradation was markedly higher (by up to 100%) in the sludge-treated soil than in the untreated soil sample. The efficiency of biodegradation of the crude oil hydrocarbons using the slurry-phase technique was compared with that of solid-phase technique. (author)
This bibliography contains citations concerning toxicity investigations of polymeric materials in food-contact applications. Polymeric food-packaging materials and regulations are discussed. Toxicity testing, polymeric equipment in food processing, and the use of additives in food packaging are included. Discussions also include coating materials for food containers and pigments for food packaging films. (This updated bibliography contains 275 citations, 10 of which are new entries to the previous edition.)
This paper presents anew design concept for a gamma irradiation plant for the continuous processing of pumpable liquids. Typical applications of such a plant include: the irradiation vulcanisation of natural latex rubber; disinfection of municipal sewage sludge for agricultural use; sterilisation of liquids in the pharmaceutical and cosmetics industries; industrial processing of bulk liquids The authors describe the design and operation of the latex irradiator now operating on a small production scale in Malaysia and proposed developments. The design allows irradiation processing to be carried out under an inert or other gaseous environment. State-of-the-art computer control system ensures the fully automatic processing operation needed by industrial computers.
In-situ sodium activated organo modified bentonite clay was also used for partial replacement of the carbon black (N330). Detailed study with the black filled compound revealed that, with slight modification of the curing package, up to 10 phr of the carbon black replacement is possible. At equivalent loading of 5 and 10 phr of in-situ sodium activated organo modified bentonite clay exhibited better properties in comparison to carbon black filled compound.
This bibliography contains citations concerning the recycling of scrap plastic produced in the injection-molding process. Plastic pellets made from scrap that are used in the injection-molding process are also discussed. Recycling equipment and automated recycling systems are described. Ways to utilize plastic scrap from used cars, packaging materials, and waste from polyurethane production are presented. (This updated bibliography contains 102 citations, 13 of which are new entries to the previous edition.)
This bibliography contains citations concerning the recycling of scrap plastic produced in the injection-molding process. Plastic pellets made from scrap that are used in the injection-molding process are also discussed. Recycling equipment and automated recycling systems are described. Ways to utilize plastic scrap from used cars, packaging materials, and waste from polyurethane production are presented. (This updated bibliography contains 116 citations, 14 of which are new entries to the previous edition.)
The bibliography contains citations concerning the recycling of scrap plastic produced in the injection molding process. Plastic pellets made from scrap, that are used in the injection molding process, are also discussed. Recycling equipment and automated recycling systems are described. The reuse of plastic scrap culled from junk automobiles and packaging materials is discussed, and waste byproducts from polyurethane production are described. (Contains a minimum of 80 citations and includes a subject term index and title list.)
The bibliography contains citations concerning the recycling of scrap plastic produced in the injection molding process. Plastic pellets made from scrap, that are used in the injection molding process, are also discussed. Recycling equipment and automated recycling systems are described. The reuse of plastic scrap culled from junk automobiles and packaging materials is discussed, and waste byproducts from polyurethane production are described. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)
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This article gives a survey of the history, properties and applications of 'Kevlar' aramide fibers. For example, the 'Kevlar' para-aramide fiber is used in compound materials in ship-, aircraft- and vehicle construction. 'Kevlar' is used as a replacement for asbestos, for example in brakes, clutches and seals or as rubber reinforcement (tyres, conveyor belts, hoses). The aramide fibers also offer manufacturers of ropes, hawsers and cables a near ideal range of properties. (MM).
Development of surface monitoring of the quality of round rubber packing rings for well instruments is discussed. A method is shown for testing the rings under conditions which simulate the operating conditions. A method is proposed for rapid monitoring of the conditions for vulcanization of the rings by the method of determining the ''ring modulus.''
In the present work, quaternary chitosans as water-soluble compounds were prepared based on three-step process. Schiff bases were firstly synthesized by the reaction between the amino groups of chitosan with aliphatic aldehydes followed by a reduction with sodium borohydride (NaBH4) to form N-(alkyl) chitosans. N,N,N-(dimethyl alkyl) chitosans were then obtained by a reaction of chitosan containing N-butyl, N-pentyl, N-hexyl, N-heptyl, and N-octyl substituents with methyl iodide. The compounds were characterized using IR and NMR spectroscopy. Subsequent experiments were conducted to test their antimicrobial activities against the most economic plant pathogenic bacteria of crown gall disease Agrobacterium tumefaciens, soft mold disease Erwinia carotovora, fungi of grey mold Botrytis cinerea...
Oxygenated fuels increase fuel consumption due to their low enthalpy of combustion; however, their high antiknock index renders them suitable for use in engines with a high compression rate, increasing their thermal yield. This study evaluated the performance of biorenewable oxygenated fuels (ethanol and isoamyl alcohol) and partially renewable fuels (ETBE: ethyl tert-butyl ether, TAEE: tert-amyl ethyl ether and di-TAE: di-tert-amyl ether) with high degree of purity and in mixtures with automotive gasoline, based on tests with Otto cycle engines. Among the oxygenated fuels evaluated here, di-TAE was found to present the best characteristics of performance, both individually and in mixtures with gasoline. 40 refs., 5 figs., 2 tabs.
Oxygenated fuels increase fuel consumption due to their low enthalpy of combustion; however, their high antiknock index renders them suitable for use in engines with a high compression rate, increasing their thermal yield. This study evaluated the performance of biorenewable oxygenated fuels (ethanol and isoamyl alcohol) and partially renewable fuels (ETBE: ethyl tert-butyl ether, TAEE: tert-amyl ethyl ether and di-TAE: di-tert-amyl ether) with high degree of purity and in mixtures with automotive gasoline, based on tests with Otto cycle engines. Among the oxygenated fuels evaluated here, di-TAE was found to present the best characteristics of performance, both individually and in mixtures with gasoline.
Synergism has been observed during inhibiting initiated oxidation of styrene or tetralin by organic phosphites in the presence of complex compounds of some transition metals. The results are given of non-additive intensification of antioxidative activity of triphenylphosphite (TPP) and tri-(4-methyl-6-tert.-- butyl)-phenyl-phosphite (TMBP) in the process of initiated oxidation of styrene or tetralin with addition of acetylacetonates of cobalt and vanadyl. During styrene oxidation, inhibition of the reaction with chelate complex of vanadyl is weakened considerably when phosphite is added into the reaction system. During tetralin oxidation, postcatalytic (or branched) oxidation is observed only for large concentration of vanadyl complex. Addition of TPP to above complex sharply increases the induction period. When the induction period is completed, oxidation of tetralin follows the mechanism of usual, i.e. initiated, reaction.
Investigates polarographically determined capacitative curves of Soviet anthracite (Removsk seam) in solutions of KCl, HCl, phenol, propyl, butyl, amyl and hexyl alcohols. The curves were found to be asymmetric and to raise quickly in their cathode range. Their dependence on electrolyte concentration and displacements of their zero charge points were observed. Displacement values of zero charge potential were tabulated for organic compounds. It was possible to calculate displacements taking the non-uniformity of coal structure into account. It was further possible to assess surface interactions between coal and adsorbed molecules from the viewpoint of molecular energy. Orientation of phenol and alcohol molecules on the coal surface is also pointed out. 10 refs.
Extraction of hafnium by 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HL) in benzene, toluene, chloroform and tetrachloromethane from aqueous-alcoholic solutions of the formal acidity of 2M-HClO_4 was studied. Methyl, ethyl, n- and isopropyl, tert-butyl and allyl alcohol as well as ethylene glycol monomethyl ether and propylene glycol were used as organic components of the mixed aqueous-organic phase. Their presence in some cases resulted in a synergic increase in the distribution ratio of hafnium. The increase is interpreted using the results of a slope analysis and measurements of the alcohol distribution and the relative permittivity of the organic phase. It is suggested that HfL_4 molecules were solvated by alcohol molecules in the organic phase. At high alcohol concentration synergism changed into antagonism. This was caused by changes in the distribution of HL and its interaction with the alcohol in the organic phase. (author).
A novel electrogenerated chemiluminescence (ECL) sensor based on natural clay and ionic liquid was fabricated. Tris(2,2prime-bipyridine)ruthenium(II) (Ru(bpy)32+) was immobilized on natural clay surface through simple adsorption. An ECL sensor was prepared by mixing Ru(bpy)32+-incorporated clay, graphite powder and an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) as the binder. The electrochemical behavior and ECL of the immobilized Ru(bpy)32+ was investigated. It was observed that the ECL of immobilized Ru(bpy)32+ was activated by the ionic liquid. The proposed ECL sensor showed high sensitivity to tri-n-propylamine (TPrA) and the detection limit was found to be 20 pM. In addition, the ECL sensor displayed good stability for TPrA detection and long-term storage stability.
Any molecule which has a hydrogen atom attached directly to oxygen or nitrogen is capable of hydrogen bonding. The molecular complexes formed by hydrogen have particularly attracted considerable attention to understand the nature of the bond. The hydrogen bonded complexes formed by acetonitrile with certain alcohols such as tertiary butyl alcohol, isoamyl alcohol, cyclohexyl alcohol, hexyl alcohol and diethylene glycol in benzene were studied. The dipole moments of 1:1 complexes of the above said systems were determined at 308K. The dipolar increments for these systems were computed from the bond angle data available from molecular orbital studies. All these studied systems show that polarization interaction dominates in all the complexes.
Normal butylamine compounds are studied as salt-free wash reagents for degraded solvent used in PUREX process in spent fuel reprocessing. The solvent wash tests were carried out with two types of butylamine compounds, n-butylamine oxalate and n-butylamine bicarbonate, by counter-current mode using a small size mixer-settler composed of two 4-stage wash steps. Di-n-butyl phosphoric acid (HDBP), the main degradation product from TBP, was removed from real degraded solvent with decontamination factor of 2.5 {approx} 7.9. The study on electrolytic decomposition of butylamine compounds was also conducted for waste treatment.
Although magnesium is not attacked by hydrocarbons, it reacts vigorously with anhydrous methanol, raising concerns about the compatibility of the metal with methanol blend fuels. This paper describes the behavior of magnesium alloys in laboratory tests in static contact with methanol-containing fuels at 110/sup 0/F. Water in small concentrations (above 0.25% by weight of the methanol content) is shown to prevent the destructive attack of magnesium by these fuels. The required water content is well within the water tolerance of methanol-GTBA (gasoline grade tertiary-butyl alcohol) cosolvent fuel blends. Die cast AZ91HP shows greater resistance to methanol reaction than does AZ31B sheet.
The main problems with the use of neat vegetable oils in diesel engines are higher smoke levels and lower thermal efficiency as compared to diesel. The problem can be tackled by inducting a gaseous fuel in the intake manifold along with air. In this investigation, hydrogen is used as the inducted fuel and rubber seed oil (RSO), rubber seed oil methyl ester (RSOME) and diesel are used as main fuels in a dual fuel engine. A single cylinder diesel engine with rated output of 4.4 kW at 1500 rpm was converted to operate in the dual fuel mode. Dual fuel operation of varying hydrogen quantity with RSO and RSOME results in higher brake thermal efficiency and significant reduction in smoke levels at high outputs. The maximum brake thermal efficiency is 28.12%, 29.26% and 31.62% with RSO, RSOME and diesel at hydrogen energy share of 8.39%, 8.73% and 10.1%, respectively. Smoke is reduced from 5.5 to 3.5 BSU with RSOME and for RSO it is from 6.1 to 3.8 BSU ...
In Chapter 2 the evaluation methods of input ground motions for seismic design are summarized and especially the empirical and/or stochastic Green's function method is introduced in order to calculate the broadband strong motions based on the physically reliable fault model. Then the evaluation procedure is applied to the Ulsan fault system near which Wolsung nuclear power plant is located. In chapter3, the PSHA case studies for Wolsung NPP site are performed, in which multi attenuation equations of earthquake motions are adopted. Moreover, the results of seismic hazard evaluation for eight sites in Korea are shown. In addition, the contents of two literatures on seismic hazard evaluation are introduced. In chapter 4, isolation devices for emergency diesel generator have been studied. The models for friction-pendulum system, high damping rubber bearing and natural rubber bearing are developed and implemented in the TDAP-III. Then, the ...
24 isotopes of astatine element 85, are known today, three of which occur naturally as decay products of "2"1"5U and "2"5"8U, respectively. Because these isotopes being very short-lived, all experiments dealing with this heaviest element of the halogen group need be done with "2"0"9"-"2"1"1At, having half-lifes in the several hours region. Mixtures of them may be obtained either by #alpha#-bombardment (E#alpha# approximately 30-50 MeV) of "2"0"9Bi or as spallation products by the reaction of high-energy protons with thorium and uranium targets. - In its chemical reactions astatine shows a behaviour which is between an halogen and a metal. The following oxidation states have been shown to exist: -1, 0, +1, +5 and +7. At"-, AtO_2"- and AtO_4"- are the ionic species for At(-I), At(+V) and At(+VII) whereas no definite species have been established for the other oxidation states. Furthermore, At_2 could not be shown to exist as yet in contrast to ...
Pulmonary fibrosis was produced in mice treated with butylated hydroxytoluene (BHT) 400 mg/kg and immediately exposed to 80% oxygen for 3 days. This treatment regimen resulted in 47% mortality. Surviving mice exhibited significant accumulations of pulmonary collagen as evidence by increases in total lung hydroxyproline levels. The administration of indomethacin (4 mg/kg/day) on days 1-6 after BHT decreased mortality to 14% and diminished the accumulation of collagen in lung tissue. Indomethacin also enhanced survival when administered on days 1-3 after BHT/O/sub 2/ but had no effect on lung collagen levels. Treatment with indomethacin on days 4-6 after BHT had no beneficial effect. The administration of prednisolone (60 mg/kg/day) on days 1-3, 1-6, or 4-6 after BHT decreased mortality but had not effect on accumulation of lung collagen. Cis-4-hydroxyproline (400 mg/kg/day) also had no effect on pulmonary fibrosis but did enhance survival when given on days 1-3 ...
The effects of the antioxidants, vitamin E, propyl gallate, 2-t-butyl-4-methoxy phenol (BHA), 2,6-di-t-butyl-4-methoxy phenol (BHT), nor-dihydroguaiaretic acid (NDGA) and diphenyl-p-phenylene diamine (DPPD) in concentrations ranging between 0.001 per cent and 0.1 per cent have been tested on lipid peroxide formation in synthetic diet mixtures containing herring oil (10 per cent) mixed with starch (90 per cent) irradiated with #gamma#-ray doses of 100 to 2000 krad. On a weight basis NDGA, DPPD, BHA and BHT were most effective and vitamin E and propyl gallate were least effective. An antioxidant concentration of 0.01 per cent normally protected against peroxide formation after a dose of 500 krad but if the dose was increased to 1000 or 2000 krad, much higher doses of antioxidant, up to 0.1 per cent, were required to give protection. Antioxidants prevented peroxide developing during post-irradiation storage even when added after irradiation. ...
The effect of addition of rosemary and oregano extracts on the sensory quality of irradiated beef burger was investigated. Batches of beef burgers were prepared with 400 ppm of rosemary or oregano extract and a group prepared with 200 ppm of synthetic butyl-hydroxytoluene (BHT)/butyl-hydroxy-anisol (BHA) was used as a control. Half of each formulation was irradiated at the maximum dose allowed for frozen meat (7 kGy). Samples were kept under frozen conditions (-20 deg. C) during the whole storage period, including during irradiation. Two analyses were performed after 20 and 90 days to verify the influence of the addition of the different types of antioxidants and the effect of irradiation and storage time on the acceptance of the product. Thirty-three and thirty-four untrained panelists were invited to participate in the first and second test, respectively. A structured hedonic scale ranging from 1 to 9 points was used in both analyses. BHT/BHA ...
A study was conducted to determine the feasibility and the opportunity of photochemical pretreatment on the biodegradation and detoxification of Methyl Tert Butyl Ether (MTBE), Ethyl Tert Butyl Ether (ETBE) and Tert Amyl Methyl Ether (TAME), the most common oxygenates used as octane enhancers in unleaded gasoline. The production, storage, uses and disposal of oxygenates result in an unknown amount of groundwater pollution. Because of their high solubility, MTBE, ETBE and TAME are detected in large portions in saturated zones of aquifers. The biodegradation of these oxygenates is difficult and slow, and information regarding their biodegradability is scarce. Photo-decomposition of oxidants under appropriate UV radiation has been shown to be very effective because the hydroxyl radicals produced possess high oxidation potential. In this study, the H{sub 2}O{sub 2}/UV process was used to generate hydroxyl radicals. Maximal oxygenates transformation ...
A study was conducted to determine the feasibility and the opportunity of photochemical pretreatment on the biodegradation and detoxification of Methyl Tert Butyl Ether (MTBE), Ethyl Tert Butyl Ether (ETBE) and Tert Amyl Methyl Ether (TAME), the most common oxygenates used as octane enhancers in unleaded gasoline. The production, storage, uses and disposal of oxygenates result in an unknown amount of groundwater pollution. Because of their high solubility, MTBE, ETBE and TAME are detected in large portions in saturated zones of aquifers. The biodegradation of these oxygenates is difficult and slow, and information regarding their biodegradability is scarce. Photo-decomposition of oxidants under appropriate UV radiation has been shown to be very effective because the hydroxyl radicals produced possess high oxidation potential. In this study, the H_2O_2/UV process was used to generate hydroxyl radicals. Maximal oxygenates transformation was ...
The design and parameters of a UV-VUV spontaneous radiation source - an excilamp operating on chlorides of rare gases ArCl{sup *}, KrCl{sup *} and XeCl{sup *} in the wavelength range 175-308 nm are presented. The Ne-Xe(Kr, Ar)-HCl mixtures were excited by a high-pressure self-sustained discharge with spark preionisation. It is shown that upon pumping mixtures of rare gases and halogens by a transverse discharge, the intensities of the B-X emission band of molecules ArCl{sup *}, KrCl{sup *} and XeCl{sup *} are comparable and up to 90% of the emission energy of excilamps can be concentrated in the UV region. The peak UV power density at 222 and 308 nm on the output window of the excilamp was {approx}2 kW cm{sup -2} for the pulse energy up to {approx} 3 mJ. The output emission energy of the excilamp at 175 nm achieved {approx}0.6 mJ and the peak power density was {approx}0.4 kW cm{sup -2}. (laser applications and other topics in quantum electronics)
Palladium/magnetite nanoparticulate catalysts were developed for efficient elimination of halogenated organic pollutants from contaminated wastewater. Particle recovery from treated water can be ensured via magnetic separation. However, in worst-case scenarios, this catalyst removal step might fail, leading to particle release into the environment. Therefore, a toxicological study was conducted to investigate the impact of both pure magnetite and palladium/magnetite nanoparticle exposure upon human skin (HaCaT) and human colon (CaCo-2) cell lines and a cell line from rainbow trout gills (RTgill-W1). To quantify cell viability after particle exposure, three endpoints were examined for all tested cell lines. Additionally, the formation of reactive oxygen species was studied for the human cells. The results showed only minor effects of the particles on the tested cell systems and support the assumption that palladium/magnetite nano-catalysts can be implemented for a ...
The activated charcoal treatment in the field of the water treatment is applied to water supply, sewage, industrial water supply and industrial sewage, etc.. Its main treatment effects are (1) decolorization, (2) removal of odorous substance, (3) removal of organic material which is detected as COD or BOD, (4) removal of harmful substance, (5) removal of substance which could generate muddness and tarnish and (6) removal of organic material which affects the succeeding high degree treatment badly, etc.. Many actual application examples in the above fields have been reported. As the most recent topic, a big amount of the demand of activated charcoal is expected in the treatment of water supply. Chlorine which is used as disinfectant during the water purification process generates organic halogen compounds such as trihalomethane through the reaction with precursor such as humic acid. The countermeasure therefore is being developed in the direction of removing the ...
Three abiotic systems are described that catalyze the reductive dehalogenation of heavily halogenated environmental pollutants, including carbon tetrachloride, trichloroethene, and perchloroethene. These systems include (a) an electrolytic reactor in which the potential on the working electrode (cathode) is fixed by using a potentiostat, (b) a light-driven system consisting of a semiconductor and (covalently attached) macrocycle that can accept light transmitted via an optical fiber, and a light-driven, two-solvent (isopropanol/acetone) system that promotes dehalogenation reactions via an unknown mechanism. Each is capable of accelerating reductive dehalogenation reactions to very high rates under laboratory conditions. Typically, millimolar concentrations of aqueous-phase targets can be dehalogenated in minutes to hours. The description of each system includes the elements of reaction mechanism (to the extent known), typical kinetic data, and a discussion of the ...
A historical review on insulated cables for power transmission, is presented, beginning with impregnated paper insulation, oil filled cables and natural rubber cables. High density and chemically reticulated polyethylene were then used for high voltage and very high voltage cables; the advantages of polyethylene compared to impregnated paper cables are discussed, which led to research programs at EDF on various themes concerning the optimization of polyethylene cables: dielectric properties and reliability, thermomechanical behaviour, thermal ageing of materials, testing methods (acceptance dielectric test and long duration temperature test); utilization of low- and high-density and chemically reticulated polyethylene for 225 kV cables is discussed
Utilization of microwaves for heating purposes began in the 1940`s. This new form of energy transfer offers many distinct advantages over conventional heating, such as volumetric, fast, direct, selective, instantaneous, and controllable heating. Studies of microwave processing of polymeric materials in the early 1960`s led to a successful industrial application in the rubber industry. Since the mid-1980`s, there has been a great deal of interest in microwave processing of polymeric materials. Technical issues, such as temperature uniformity and control of thermal runaway during processing, were investigated and many successful laboratory scale results were obtained from both fundamental and processing studies. This paper presents a historical perspective of microwave heating in the processing of polymer composites and discusses possible future directions for technology commercialization.
In this article, a method of producing elastic ferromagnetic composite containing particles of chemical pure iron with sizes of 0.10-0.15 mm was described. The particles were dispersed in an elastic matrix of an elastic silicone rubber. The filling factor of composite by ferromagnetic particles and porous factors were changed in the range from 0.15 to 0.45. The samples of the obtained composite were placed in the magnetic field with induction of 0-8 T, produced by the Bitter-type magnet. The longitudinal magnetostriction of samples was measured by using a coaxial capacitor with a movable plate. It was found that the maximal relative elongation of samples was 4.81% and hysteresis of magnetostriction and also remanent magnetostriction amounted to 1.08%. A slow decay of remanent magnetostriction up to 0.14% in 10{sup 5} s was also observed.
This study evaluated surface characteristics and overlaying properties of wood plastic composite (WPC) panels made from dry-blended rubber wood fiber-polypropylene (PP) powder formulations using a conventional flat-press process under laboratory conditions. Three levels of rubberwood fibers (Hevea brasiliensis), 40%, 50%, and 60%, based on the composition by weight, were mixed with the PP powder without and with 3% (based on weight) maleic anhydride grafted PP (MAPP) as a coupling agent. Contact angle measurements on the WPC samples were performed using a goniometer connected with a digital camera which collected one image per second. Roughness measurements, average roughness (R a), mean peak-to-valley height (R z), and maximum roughness (R y), were taken from the sanded samples along and ...
Many higher plants produce economically important organic compounds such as oils, resins, tannins, natural rubber, gums, waxes, dyes, flavors and fragrances, pharmaceuticals, and pesticides. However, most species of higher plants have never been described, much less surveyed for chemical or biologically active constituents, and new sources of commercially valuable materials remain to be discovered. Advances in biotechnology, particularly methods for culturing plants cells and tissues, should provide new means for the commercial processing of even rare plants and the chemicals they produce. These new technologies will extend and enhance the usefulness of plants as renewable resources of valuable chemicals. In the future, biologically active plant-derived chemicals can be expected to play an increasingly significant role in the commercial development of new products for regulating plant growth and for insect and weed control. 65 references.
Effect of oil palm empty fruit bunch (OPEFB) fiber and poly(methyl acrylate) grafted OPEFB on several mechanical properties of poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blends using HAKEE Rheomixer at the rotor speed of 50 rpm, mixing temperature 150degreeC, and mixing period of 20 min. The fiber loadings were varied from 0 to 30% and the effect of fiber content in the composites on their ultimate tensile strength (UTS), Youngs modulus, elongation at break, flexural modulus, hardness, and impact strength were determined. An increasing trend was observed in the Youngs modulus, flexural modulus, and hardness with the addition of grafted and ungrafted fiber to the PVC/ENR blends. However the i...
ABSTRACT Purpose: There is a consensus in the community of dental research that the selection of undersized artificial maxillary anterior teeth offers an unnatural appearance to the denture. Several methods to select the adequate width of these teeth are of questionable validity, and many dentures have an obviously artificial appearance. This article assessed the relationship between the individual and the combined width of maxillary anterior teeth. Materials and Methods: Impressions were made of the anterior dentition of 69 dentate undergraduate students with rubber impression silicon, and casts were formed. The individual widths of the maxillary anterior teeth were measured by using a digital caliper (SC-6 digital caliper, Mitutoyo Corporation, Tokyo, Japan), and the combined width was r...
Experimental results of quasi-static and dynamic fracture of particle-filled polymer composite (PFPCM) "ALTUGLAS EI CH25" with a matrix of polymethylmethacrylate (PMMA) are reported in this paper. PMMA matrix is filled with rubber particles, as result a shock-resistant transparent composite is produced. The main task was to investigate experimentally and theoretically the fracture toughness of this composite under static and dynamic loading. A high-rate loading has been created by impulse magnetic field. Analysis of fracture process and its relation with the load parameters and material microstructure have been established. Application of the original testing method enabled determination of fracture toughness at very short loading times and comparison of the results with material dynamic p...
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.
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.
Platinum(II) complexes (1-4) with bidentate N,Nprime-ligands, O,Oprime-dialkyl esters (alkyl = ethyl, n-propyl, n-butyl and n-pentyl), of (S,S)-ethylenediamine-N,Nprime-di-2-(4-methyl)pentanoic acid were synthesized and characterized by IR, 1H NMR and 13C NMR spectroscopy and elemental analysis. DFT calculations were performed for the complexes and it was found that only one diastereoisomer could be formed. Cytotoxic activity of complexes 1-4 was determined against chronic lymphocytic leukemia cells (CLL) and compared to the activity of ligand precursors L12HCl-L42HCl and corresponding palladium(II) complexes, [PdCl2L] (L = L1-L4). The complexes were found to exhibit significantly higher antitumor activities than cisplatin on CLL cells. Cytotoxic effect of platinum(II) complexes on CLL cel...
Simple and low cost biosensor based on screen-printed electrode for sensitive detection of some alkylphenols was developed, by entrapment of HRP in a nanocomposite gel based on single-walled carbon nanotubes (SWCNTs) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF(6)]) ionic liquid. Raman and FTIR spectroscopy, CV and EIS studies demonstrate the interaction between SWCNTs and ionic liquid. The nanocomposite gel, SWCNT-[BMIM][PF(6)] provides to the modified sensor a considerable enhanced electrocatalytic activity toward hydrogen peroxide reduction. The HRP based biosensor exhibits high sensitivity and good stability, allowing a detection of the alkylphenols at an applied potential of -0.2V vs. Ag/AgCl, in linear range from 5.5 to 97.7?M for 4-t-octylphenol and respectively, between 5.5 and 140?M for 4-n-nonylphenol, with a response time of about 5s. The detection limit was 1.1?M for 4-t-octylphenol, and respectively 0.4?M for 4-n-nonylphenol (S/N=3). ...
A procedure has been developed for producing a radiopharmaceutically pure ''no-carrier-added'' "2"0"1Tl. The procedure is based on irradiating enriched metallic thallium (> 96% "2"0"3Tl) targets with approx. 30 Mev protons, separating "2"0"1Pb by co-precipitation with SrSO_4 from sulphuric acid solution, and extracting "2"0"1Tl (after its in-growth) with butyl acetate from a hydrochloric solution. The average overall yield of "2"0"1Tl is approx. 92%. The radioactive concentration of the product exceeds 2 mCi/mL; radionuclide impurities-"2"0"0Tl <= 0.5%; "2"0"2Tl <= 0.1%; "2"0"3Pb <= 0.02%; inactive impurities (#mu#g/mL)-Tl < 2, Sr < 1, Fe < 0.25, Cu < 0.05; pH within the range 5-8. The product is sterile, apyrogenic, and suitable for clinical application. (author).
4,4'-bis(N-carbazolyl)tolan (BCT) and 4,4'-bis[N-(3,6-di-t-butyl)carbazolyl]tolan (BCT-t-Bu) were synthesized as ?-expanded analogs of 4,4'-bis(N-carbazolyl)biphenyl. Their photophysical characteristics both in solution and films were thoroughly investigated. Interestingly, the phosphorescence spectrum of BCT was significantly medium-dependent, and the emission maximum was red-shifted by 131 nm from 489 nm in solution at 77 K to 620 nm in a deposited film at 5 K, suggesting the presence of strong intermolecular interactions in the film. BCT and BCT-t-Bu were found to be useful as host materials for fluorescence-based organic light emitting diodes (OLEDs). However, their low triplet energy levels in films negated their potential to act as hosts in phosphorescence-based OLEDs. - Research highlights: ? We synthesized N-carbazolyl-tolan derivatives (BCT) as ?-expanded analogues of CBP. ? We found that BCT derivatives are useful as host materials for fluorescence-based ...
As part of our program in radiopharmaceutical chemistry we have prepared and evaluated a series of radioiodinated 1-alkyl-4-phenylpiperazines as potential brain-imaging agents. The compounds were chosen on the basis of their synthetic versatility, activation toward electrophilic substitution, and ease of purification. The intermediates 1-6 were readily obtained and converted to the corresponding radioiodinated products 7-12 in 76-91% isolated radiochemical yields. The tissue distribution in rats indicated that the 1-N-butyl derivative 9 possesses the best combination of brain uptake (0.28-0.35% ID X kg/g), retention, and selectivity (brain/blood greater than 20) over the 4-h evaluation period. A subsequent imaging and tissue distribution study in the dog using 131I-labeled 9 supported the results observed in the rat and suggested the potential of this agent as a brain-imaging agent.
We demonstrate a two-step process used to increase the hydrogen yield from sucrose and to relieve the pollution threat caused by resultant fatty acids in dark-fermentation. In batch tests of dark-fermentation using microflora, the maximum hydrogen production rate was >360 mL H{sub 2}/Lh and the maximum hydrogen yield was 3.67 mol H{sub 2}/mol sucrose. The fatty acids produced in dark-fermentation were mainly butyrate and acetate with a small amount of propionate, valerate, n-butyl alcohol, and caproate. Photo-fermentation with Rhodobacter sphaeroides SH2C was then employed to convert these small molecular fatty acids into hydrogen. The total hydrogen yield from sucrose increased from the maximum of 3.67 mol H{sub 2}/mol sucrose in dark-fermentation to 6.63 mol H{sub 2}/mol sucrose by using the two-step process. No butyrate, acetate, propionate, or valerate was detected in the final fermentation effluent after photo-fermentation. Our results suggest that a ...
The addition of paraquat (methyl viologen) to a growing culture of Escherichia coli K-12 led within 1 hr to a 10- to 20-fold increase in the level of endonuclease IV, a DNase for apurinic/apyrimidinic sites. The induction was blocked by chloramphenicol. Increases of 3-fold or more were also seen with plumbagin, menadione, and phenazine methosulfate. H_2O_2 produced no more than a 2-fold increase in endonuclease IV activity. The following agents had no significant effect: streptonigrin, nitrofurantoin, tert-butyl hydroperoxide, #gamma# rays, 260-nm UV radiation, methyl methanesulfonate, mitomycin C, and ascorbate. Paraquat, plumbagin, menadione, and phenazine methosulfate are known to generate superoxide radical anions via redox cycling in vivo. A mutant lacking superoxide dismutase was unusually sensitive to induction by paraquat. In addition, endonuclease IV could be induced by merely growing the mutant in pure O_2. The levels of endonuclease IV in uninduced or ...
Crystalline bis(O,O'-di-sec-butyldithiophosphato)platinum(II) was prepared and studied by means of 13C, 31P CP/MAS NMR spectroscopy and single-crystal X-ray diffraction. The unit cell of the platinum(II) compound is comprised of one centrosymmetric mononuclear molecule [Pt{S2P(O-sec-C4H9)2}2], in which the dithiophosphate groups display structural equivalence in both 31P NMR and XRD data. A pair of the dithiophosphate ligands exhibit the same S,S'-bidentate chelating structural function and form two planar four-membered chelate rings, [PtS2P], in this molecule. The planar configuration of the [PtS4] chromophore in structure 1 is governed by the dsp2-hybrid state of platinum(II). The structural states of the dithiophosphate groups in two different samples of complex 1 (one crystallised from...
Abstract Coordination compounds [Ru(acac)2(Q)] (acac=acetylacetonate; Q=o-benzoquinone) were prepared as complexes 1 (Q=o-benzoquinone), 2 (Q=3-methoxy-o-benzoquinone), 3 (Q=4-methyl-o-benzoquinone), and 4 (Q=3,5-di-tert-butyl-o-benzoquinone). The structures of 1 and 2 were determined to reveal a RuIII/o-benzosemiquinone formulation, supported by analysis of experimental data (spectroscopy, magnetism of 1) and by DFT calculations. The S=1 ground state calculated for 1 stands in contrast to the spin-paired analogues with arylimino-o-benzosemiquinonato and diimino-o-benzoquinone ligands. The close contacts of about 5.3- possible between semiquinone O atoms of different molecules in the crystal allow for intermolecular spin-spin interactions and an overall complex magnetic behavior. One quasi...
The tri-n-butyl phosphate(TBP) extraction behavior of tritium was studied to support the evaluation of tritium confinement in the Purex process. The tritium distribution ratio in the system of U - 30% TBP/n-dodecane(nDD) - HNO[sub 3] [minus]H[sub 2]O was measured in batch-wise experiments. The tritium decontamination factor in a tritium scrubbing step was measured in chemical flow sheet experiments using a 6 stage mixer-settler having an internal recycle system of aqueous solution in each stage. Tritium was mainly extracted in the forms of water and nitric acid in the system. Less than 1% of the amount of tritium in the organic phase was fixed in the degradation products of the solvent. A tritium decontamination factor of about 500 in the tritium scrubbing step was obtained under the conditions of about 85 g-U/dm[sup 3] of uranium concentration in the irradiated solvent(30% TBP/nDD), 3 M nitric acid in the tritium scrubbing solution and an organic: aqueous phase ...
Computational fluid dynamics are applied to the study of three-dimensional fluid flow in a dense medium plasma reactor (DMPR) under different operating conditions. Reaction mechanisms and rates for the removal of methyl t-butyl ether (MTBE) in a DMPR are developed from experimental data to determine the plasma volume, the rate of interphase mass transfer and the photolysis rate of MTBE via UV emission from the plasma. The simulations utilize the plasma volume determined from the kinetic data to show that the volume of fluid in contact with the plasma in the DMPR only constitutes a maximum of approximately 10% of the fluid intended to be cycled through the plasma tubules. The simulations also predict appreciable pressure gradients on the surface of the pin electrodes, resulting in a small discharge area located away from the region in which the electric field strength is a maximum. This result has been confirmed indirectly through observation in that the pin ...
A series of Model Tests of Embedment Effect on Reactor Buildings has been carried out by the Nuclear Power Engineering Corporation (NUPEC), under the sponsorship of the Ministry of International Trade and Industry (MITI) of Japan. Reactor buildings in Japan are partially embedded in general. Therefore, it is important to know how partial embedment affects the vibration characteristics of reactor buildings relating to seismic safety. Laboratory tests were conducted using a ground model made of silicone rubber (Young's modulus 2.3x10"6 Pa, Poisson's ratio 0.484, Density 1.24x 10"3 kg/m3 , Damping ratio 0.01) and a foundation model made of aluminum shown to study the effects of embedment on soil-structure interaction with different backfill types. The ground model is a cylinder, 70 cm high and 300 cm in diameter, with pit where the parallelepiped foundation model with square plan of 30 cm x 30 cm and 18 cm high was placed. Four types of backfill of silicone ...
The dynamic mechanical properties and molecular weight distribution of two experimental polymer bonded explosives, X-0287 and X-0298, maintained at 23, 60, and 74/sup 0/C for 3 years were examined. X-0287 is 97% 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane explosive, 1.8% Kraton G-1650, and 1.2% B/sup 2/ was 170. X-0298 is 97.4% explosive, 1.4% Kraton G-1650, and 1.2% Cenco Hi-vac oil. The relaxation associated with the Kraton rubber block glass transition is observed in both X-0287 and X-0298. In the unaged X-0298 it occurs at -59/sup 0/C and in the aged explosive at 50/sup 0/C. This is caused by migration of the oil plasticizer out of the explosive. In X-0287 the Kraton rubber block T/sub g/ is weak and broad due to the presence of the wax plasticizer. X-0287 has a second broad relaxation associated with the melting of the wax from 10 to 65/sup 0/C. The molecular weight of the Kraton binder decreased with increasing accelerated aging ...
A characteristic of filled elastomers is their ability to undergo very large deformations without damaging their internal structure. The material behaviour is mainly elastic, however, elastomers show hysteresis effects leading to damping properties, which are quite important as regards their applications in various fields of mechanical engineering.A series of experiments (tension, torsion and combinations of both) was carried out on cylindrical bars made of a carbon-black filled rubber mixture. In addition to a pronounced nonlinear rate-dependence, relaxation and viscosity properties are observed as being influenced by the process histories.The behaviour of elastomeric materials is modelled on the basis of a free energy function and evolution equations for additional internal variables. Incorporating or disregarding the very small rate-independent hysteresis, the constitutive modelling may be classified under viscoplasticity or viscoelasticity. The constitutive ...
This paper reports on the protection of opening that are exposed to the environment in nuclear facilities which presents an almost overwhelming engineering challenge. Intakes and outflows must permit the passage of large volumes of air or water without impeding their flow, and they are often exposed to corrosive salt and chemicals. An intrusion detection sensor that is intended to protect these openings must be capable of operating reliably under environmentally harsh conditions, and at the same time either provide a physical delay barrier or attach to an existing barrier. A new fiber optic sensor technology has now been developed specifically for protecting environmentally exposed openings. This sensor uses a fiber optic cable embedded in a neoprene rubber frame which is reinforced with Kevlar threads or braided steel cable. The sensor is configured in a mesh pattern with openings sufficiently large to permit air or water to flow unimpeded, but small enough to ...
Abstract Toughening amplification of the neat poly(vinyl chloride) (PVC) and its reinforced version containing 25 phr of the cellulose acetate (CA)-compatibilized starch using methyl methacrylate-butadiene-styrene (MBS) core-shell particles was studied. The room temperature measured impact strength of the PVC showed mild increase up to 10 wt % with the addition of MBS particles. Then, the toughness enhanced discontinuously to super-tough plateau regime. The room temperature measured impact strength of PVC containing 20 phr of MBS particles, however, was reduced by as much as 95% when it was filled with 25 phr of the CA-compatibilized starch. In addition, the brittle-ductile transition (BDT) of the toughened PVC increased from 0 to 60 C because of its reinforcement, even though the matrix n...
The separation of bitumens (B) and natural asphalts using a dialysis (D) method is studied. A moderately vulcanized latex of natural rubber, which was subjected to extraction by cold n-hexane prior to use, was used as the material of the membrane for dialysis. With dialysis of bitumen samples dispersed in a small quantity of n-alkane in a Soxhlet apparatus three fractions were acquired: a dialyzate, an undialyzable fraction and asphaltenes (the residue). N-pentane, n-hexane and n-heptane were used as the solvents for dialysis. Samples of oxidized road bitumen, grade AOSI 85/25, bitumens from the process of propane deasphaltization, natural asphalts from Trinidad and Albania and A80 grade bitumens from the oil distillation process were isolated using the dialysis method. The reproducability of the output of the fractions with varying suspensions and productivity of the dialysis, the dependence of the output on the length of the dialysis, the dependence of the output ...
In this paper, results on ozone production by atmospheric pulsed discharge, are reported. In the research, two types of ozonizer (Type I and Type II) have been used to investigate improvements of ozone concentration and production efficiency. The ozonizer has plane-to-plane metal electrodes structure, and pre-ionization electrodes are placed on the high voltage electrodes (Type I). In Type II, the surface of grounded electrode with 20 mm of width is covered partly by dielectric (thin rubber) with 11 mm of width, while the geometry of both metal electrodes is same to Type I. In the case of Type I, maximum concentration of about 100 ppm and maximum yield of 70 g/kWh were obtained at input power of 0.3 W. On the other hands, in the case of Type II, 800 ppm and 100 g/kWh were obtained at input power of 1.5 W. It was found that the ozone concentration and production yield were improved by using electrode covered by dielectric. (author)
The effect of irradiation on the tensile properties of oil palm empty fruit bunch (OPEFB) fiber reinforced poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blend using HAAKE Rheomixer at 150 deg. C. The composites were then irradiated by using a 3.0 MeV electron beam machine at doses ranging from 0 to 100 kGy in air and room temperature. The tensile strength, Young's modulus, elongation at break and gel fraction of the composites were measured. Comparative studies were also made by using poly(methyl acrylate) grafted OPEFB fiber in the similar blend system. An increase in tensile strength, Young's modulus and gel fraction, with a concurrent reduction in the elongation at break (Eb) of the PVC/ENR/OPEFB composites were observed upon electron beam irradiation. Studies revealed that grafting of the OPEFB fiber with methyl acrylate did not cause appreciable ...
Non-invasive methods are described for estimating local cerebal blood flows (LCBF) and local partition coefficients (Llambda) during inhalation of 30 % stable xenon gas (Xe) in oxygen during CT scanning. After the denitrogenation with pure oxygen breathing, 30 % Xe is inhaled for four minutes to minimize subanesthetic effects with a rubber facemask and the delivery system of Xe. Local time-..delta.. Hounsfield units curve during the Xe wash-in and wash-out phase is utilized in order to calculate Llambda and LCBF using a least squares curve fitting analysis. Calculated Llambda and LCBF with the new method manifested reasonable distribution between the grey and white matters, and reproducibility was excellent in our study. Several case studies of patients with cerebral infarction are presented to demonstrate the characterization of Llambda and LCBF patterns in various tissues and theoretical grounds underlying the new method of curve fitting analysis are discussed.
Non-invasive methods are described for estimating local cerebal blood flows (LCBF) and local partition coefficients (L#lambda#) during inhalation of 30 % stable xenon gas (Xe) in oxygen during CT scanning. After the denitrogenation with pure oxygen breathing, 30 % Xe is inhaled for four minutes to minimize subanesthetic effects with a rubber facemask and the delivery system of Xe. Local time-#DELTA# Hounsfield units curve during the Xe wash-in and wash-out phase is utilized in order to calculate L#lambda# and LCBF using a least squares curve fitting analysis. Calculated L#lambda# and LCBF with the new method manifested reasonable distribution between the grey and white matters, and reproducibility was excellent in our study. Several case studies of patients with cerebral infarction are presented to demonstrate the characterization of L#lambda# and LCBF patterns in various tissues and theoretical grounds underlying the new method of curve fitting analysis are ...
A transition from petroleum~derived jet fuels to blends with Fischer-Tropsch (F~T) fuels, and ultimately fully synthetic hydro-isomerized F-T fuels has raised concern about the fate of plasticizers in nitrile-butadiene rubber a-rings that are contacted by the fuels as this transition occurs. The partitioning of plasticizers and fuel molecules between nitrile a-rings and petroleum-derived, synthetic, and additized-synthetic jet fuels has been measured. Thermal desorption of o-rings soaked in the various jet fuels followed by gas chromatographic analysis with a mass spectrometric detector showed many of the plasticizer and stabilizer compounds were removed from the o-rings regardless of the contact fuel. Fuel molecules were observed to migrate into the o-rings for the petroleum-derived fuel as did both the fuel and additive for a synthetic F-T jet fuel additized with benzyl alcohol, but less for the unadditized synthetic fuel. The specific compounds or classes of ...
Describes investigations into flow density, angle of repose, coefficients of friction and adhesion using poor quality anthracite culm (from the 50-letie Ukrainy mine) and anthracite slurry with a high ash content (from the Tsentral'naya and Partizanskaya mines) on samples of varying moisture content (2-22%). The results show that flow properties are impaired when anthracite has a moisture content of 8.5 to 9.5%; when these anthracites are used in electric power plants they should be stored in bunkers with walls with a slope of greater than 70 degrees (or dried) to prevent sticking. Results of investigations into internal and external friction, adhesion and cohesion varied for the different samples, but the highest coefficient of internal friction was found with concrete where it increases continuously with moisture content. With rubber, PVC, St. 3 steel and stainless steel, the friction coefficient increases with moisture content at first, then gradually ...
AGNES is a chopper spectrometer installed at the top of the C3 cold guide of JRR-3 (JAERI, Tokai). In 2004 - 2006, this spectrometer was greatly improved by installing (1) 208 new detectors to make the detector bank complete, (2) new radiation shields composed of Fe (14 mm), polyethylene (50 mm), B4C rubber (10 mm), and Cd (0.5 mm) sheets, (3) a new control system for the anti-frame-overlap chopper rotating simultaneously with the Fermi chopper, (4) a monitor counter at the space between the chopper and monochromator, (5) a neutron guide tube (50 cm) before the monochromator, (6) a new instrument control (monochromators, choppers, beam narrowers, etc.) and measurement control (real-time data monitoring, sample temperature control, etc.) systems, (7) a top-loading type cryostat workable at a wide temperature range of 6 - 480 K. As the results of these improvements, the signal intensity has been increased by 3.3 and the background has been reduced by 1/10 both ...
The 105-KE and 105-KW Fuel Storage Basins were constructed more than 35 years ago as repositories for irradiated fuel from the K East and K West Reactors. Currently, the basins contain irradiated fuel from the N Reactor. To continue to use the basins as desired, seismic adequacy in accordance with current US Department of Energy facility requirements must be demonstrated. The 105-KE and 105-KW Basins are reinforced concrete, belowground reservoirs with a 16-ft water depth. The entire water retention boundary, which currently includes a portion of the adjacent reactor buildings, must be qualified for the Hanford Site design basis earthquake. The reactor building interface joints are sealed against leakage with rubber water stops. Demonstration of the seismic adequacy of these interface joints was initially identified as a key issue in the seismic qualification effort. The issue of water leakage through seismicly induced cracks was also investigated. This issue, ...
Abstract Ethylene-propylene-diene rubber (EPDM)/samarium borate (SmBO3)/ethylene-vinyl acetate (EVA) copolymer and EPDM/antimony-doped tin oxide (ATO)/EVA composites are aged at 150C for different intervals. Surface modification is used to improve filler to matrix interphase. The main aim is to investigate the effect of filler type and vinyl acetate (VA) content in EVA on stability of EPDM composites. It is found that acidic ATO particles can lower pH level of EPDM composites and then promote the degradation of acetic acid during aging. Moreover, when VA content exceeds 14 wt %, the instable VA content causes more acetic acids escape during aging. With the increasing of aging time, EPDM/SmBO3 control and EPDM/SmBO3/EVA composites tend to become darker while EPDM/ATO and EPDM/ATO/EVA compos...
Local blood flow in the thigh was measured with /sup 133/Xe clearance technique in eight male distance runners after compression with a foam rubber compress and a standard elastic bandage. Two degrees of compression were tested, and an initial experiment with rested subjects was followed by a similar experiment immediately after running. Maximum compression exerted a cutaneous pressure of 85 (+/- 8) mm Hg and caused an immediate cessation of intra-muscular blood flow in the compressed area. Moderate compression gave a cutaneous pressure of 40 (+/- 5) mm Hg and resulted in a reduction of blood flow by approximately 50%. During compression, there were no significant differences in the blood flow of rested subjects compared to subjects immediately after running. In acute soft tissue injuries, a maximum compression bandage should effectively reduce or eliminate the formation of an intra-muscular hematoma, and an additive effect on blood flow of ice should not be ...
The thermal neutron column of the JRR-2 reactor was remodelled in order to install a medical irradiation facility. The design experience and the cource of this remodelling are presented. At first, the thermal neutron flux was lower than expected, and the expected radiation condition was achieved by the following improvements: (1) removal of graphite from the thermal neutron column to increase the neutron flux, (2) twice increase of bismuth shielding and the shift of its position to improve the shielding effect against gamma ray, (3) application of B{sub 4}C rubber on the both surfaces of the shielding door to suppress the secondary gamma ray generation from the structural materials, (4) LiF tiles are applied on the inner face of the neutron beam exit hole to suppress the secondary gamma ray from the beam exit, and (5) installment a cone-shape polyethylene collimator to relieve the decay of thermal neutron. After the improvements, medical irradiation treatments have ...
A suspension-firing type radioactive waste incineration system is developed and cold demonstration testing of ceramic filters for the system are carried out. The incineration system, which is useful for a wide variety of waste materials, can serve to simplify the facilities and to reduce the costs for waste disposal. The incineration system can be used for drying-processing of concentrated waste liquids and disposal of flame resistant materials including ion exchange resins and rubber, as well as for ordinary combustible solid materials. An on-line backwash system is adopted to allow the ceramic filters to operate stably for a long period of time. For one-step filtering using the ceramic filter, the decontamination factor is greater than 10"5 for the processing of various wastes. In a practical situation, there exist vapor produced by the spray drier and the cladding in used ion exchange resin, which act to increase the decontamination performance of the ceramic ...
This paper evaluates abrasive jet wear tests, carried out on the ZUK-3M abrasion apparatus according to the GOSF 23.201-78 industrial standard. As abrasive material, brown coal coke dust, brown coal dust, power plant fly ash and quartz sand (for the purpose of comparison) were employed. Seventeen types of materials were blasted with abrasive jets, including a selection of steels, glass, rubber, SYS-pur plastics, cast basalt, Kawenit and vitroceramics. The test apparatus produced abrasive jet velocities between 12 and 130 ms/SUP/-/SUP/1 at rotor revolutions of 1,000 to 10,000 min/SUP/-/SUP/1. Blasted material samples were arranged at angles between 15 and 90 degrees. Various tables and graphs present abrasivity results. These results were employed for technical modifications of dedusting equipment in briquetting and coking plants, which led to a threefold increase in service life of abrasion endangered equipment parts. (8 refs.) (In German)
The turbulent history of legislature concerned with the waste-management industry and the amount of material on this subject as well as the significance of the material in its own right led to the decision to publish all legal regulations on waste in one volume. It includes above all the Waste Law, Regulations on Determination of Waste, Regulations on Determination of Residual Products, Technical Instructions for Waste, Regulations for Monitoring Waste and Residual Products, Regulations on Probition from the Use of Chlorofluorohydrocarbons and Halon, Regulations on Packaging and Regulations on Sewage Sludge. The introduction explains the development and the role of the Waste Law and its applicability, goals and principles: The concept of waste, avoidance of waste, avoidance of waste tourism, the general welfare of the public; regulations on waste management, governmental means of monitoring waste management: Obligations to dispose of waste, compulsory waste-management plants and ...
The palladium(II) and platinum(II)complexes(where, (M(L){sub 2}X{sub 2}), M=Pd(II), Pt(II); L=isoxazole (isox), 3, 5-dimethylisoxazole(3, 5-diMeisox), 3-methyl, 5-phenylisoxazole(3-Me, 5-Ph-isox), and 4-amino-3, 5-di-methylisoxazole (4-ADI); X=Cl, Br) with isoxazole and its derivatives were investigated on antitumor activity by MM2 and EHMO calculation. Because for all the complexes the {sigma}MO energy level (E{sub {sigma}}{sub (M-X)} between d{sub x}{sup 2}{sub -y}{sup 2} orbital of central metal and p{sub x} orbital of halogen atom is less than {sigma}MO energy level E{sub {sigma}}{sub (M-N)} between d{sub x}{sup 2}{sub -y}{sup 2} orbital of central metal and p{sub x} orbital of N atom, without exception. And judging, from the lower E{sub {sigma}}{sub (M-X)} value in trans, the bonding strength was found to be weaker in trans isomer than in cis. For the Pd(II) and Pt(II) complexes which have planar ligands, it was shown that for all the complexes dissociation of ...
Embryos of chicken (Gallus domesticus), domestic duck (Anas platyrhynchos), and common eider duck (Somateria mollissima) were exposed in ovo to PCBs and to polycyclic aromatic hydrocarbons. Two coplanar PCBs, 3,3{prime},4,4{prime}-tetrachlorobiphenyl (PCB {number_sign}77) and 3,3{prime},4,4{prime},5-pentachlorobiphenyl (PCB {number_sign}126), were considerably more lethal and potent as inducers of 7-ethoxyresorufin O-deethylase (EROD) in chicken embryos (Gallus domesticus) than in embryos of the other two species. In chicken embryos, these compounds caused edema and eye and beak deformities. An artificial mixture of 18 PAHs which all have been detected in environmental samples, was slightly more toxic to embryos of the domestic duck and the common eider duck than to chicken embryos. The most potent compound in the mixture was benzo(k)fluoranthene. When chicken embryo livers were exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in vitro, EROD was induced by very low concentrations ...
In 1977 and 1978, workers at Idaho National Engineering Laboratory (INEL) developed and tested a process for the regeneration and reuse of silver mordenite, AgZ, used to trap iodine from the dissolver off-gas stream of a nuclear fuel reprocessing plant. We were requested by the Airborne Waste Management Program Office of the Department of Energy to perform a confirmatory recycle study using repeated loadings at about 150/sup 0/C with elemental iodine, each followed by a drying step at 300/sup 0/C, then by iodine removal using elemental hydrogen at 500/sup 0/C. The results of our study show that AgZ can be recycled. There was considerable difficulty in stripping the iodine at 500/sup 0/C.; however, this step went reasonably well at 550/sup 0/C or slightly higher, with no apparent loss in the iodine-loading capacity of the AgZ. Large releases of elemental iodine occurred during the drying stage and the early part of the stripping stage. Lead zeolite, which was employed in the original ...
During third quarter 1994, samples from AMB groundwater monitoring wells at the Metallurgical Laboratory Hazardous Waste Management Facility (Met Lab HWMF) were analyzed for selected heavy metals, indicator parameters, radionuclides, volatile organic compounds, and other constituents. Eight parameters exceeded standards during the quarter. As in previous quarters, tetrachloroethylene and trichloroethylene exceeded final Primary Drinking Water Standards (PDWS). Bis(2-ethylhexyl) phthalate exceeded final PDWS in one well. Aluminum, iron, manganese, tin, and total organic halogens exceeded the Savannah River Site (SRS) Flag 2 criteria. Groundwater flow direction and rate in the M-Area Aquifer Zone were similar to previous quarters. Conditions affecting determination of groundwater flow directions and rates in the Upper Lost Lake Aquifer Zone, Lower Lost Lake Aquifer Zone, and the Middle Sand Aquifer Zone of the Crouch Branch Confining Unit were also similar to ...
Mild hydrotreating is the key to successful re-refining of used lubricating oils. Coupled with pre-distillation and metals removal, the process produces oil of superior color and clarity with acceptable viscosity and heteroatom content. Furthermore, the entire process provides operational simplicity, economic feasibility and environmental attractiveness. Re-refining preserves a valuable resource while solving a potential environmental problem. Increased sensitivity to disposal of hazardous material once again makes re-refining almost a necessity. Various technologies developed to re-refine used lubricating oils range from simple acid/clay contacting to complex solvent extraction. Most technologies require similar capital investment; however, operating costs vary substantially. Current technology seems to converge on a two-step procedure: distillation of dehydrated used oil in a thin-film evaporator, and subsequent hydrotreating of distilled stocks. Filtered used oil is first dehydrated ...
Present and potential future changes to the global environment have important implications for marine pollution and for the air-sea exchange of both anthropogenic and natural substances. This report addresses three issues related to the potential impact of global change on the air-sea exchange of chemicals: Global change and the air-sea transfer of the nutrients nitrogen and iron. Global change and the air-sea exchange of gases. Oceanic responses to radiative and oxidative changes in the atmosphere. The deposition of atmospheric anthropogenic nitrogen has probably increased biological productivity in coastal regions along many continental margins. Atmospheric deposition of new nitrogen may also have increased productivity somewhat in mid-ocean regions. The projected future increases of nitrogen oxide emissions from Asia, Africa and South America will provide significant increases in the rate of deposition of oxidized nitrogen to the central North Pacific, the equatorial Atlantic, and ...
Based on results from recent studies of elemental dietary intake and organ or tissue content for adult Chinese men, quoted nationwide elemental concentrations in Chinese soil and newly published national average consumption of dietary foods, values of both transfer coefficients and discrimination factor (DF) for transfer from soil via the diet to both critical organs and the whole body have been calculated for important elements in radiation protection, including alkaline earths, alkali metals, rare earths and other related elements. These calculations have used both the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) model and the DF method. In the UNSCEAR model, the basic parameters used to describe the transport of radionuclides are the transfer coefficients P_i_j, which describe the relationship of concentrations or other amounts between compartment i and the following compartment j, whereas the DF is the ratio between the transfer coefficients for ...
The solvent extraction of 12-phosphotungstic acid, also known as 12-tungstophosphoric acid-H_3PW_1_2O_4_0, the so-called Keggin heteropolyacid - by 0.73 M (20%v/v) tri-n-butyl phosphate (TBP) in n-octane under conditions comparable to those used previously for the extraction of conventional inorganic mineral acids is described. A simplified phase diagram for the pentanary system comprised of H_3PW_1_2O_4_0, HNO_3, H_2O, TBP, and n-octane reveals an extremely low initial concentration of H_3PW_1_2O_4_0 (1.1 mM) at the LOC (limiting organic concentration) condition, far lower than the most effective third-phase-forming inorganic acid, namely HClO_4. The results from small-angle neutron scattering (SANS) indicate that the interparticle attraction energy - U(r) calculated through application of the Baxter sticky sphere model to the SANS data at the LOC condition - does not approach the -2 k_B T value associated with phase splitting in previous studies of TBP ...
The effect of in vitro and in vivo administration of ethanol on the binding of "3"5S-t-butyl-bicyclophosphorothionate ("3"5S-TBPS) to cortical brain membranes of C57B1 mice was investigated using KCl (100 mM) containing assay media. The in vitro addition of ethanol produced a dose-dependent inhibition of basal "3"5S-TBPS binding. In the presence of chloride ions, GABA and pentobarbital had a biphasic action (stimulation followed by inhibition) on "3"5S-TBPS binding, whereas diazepam only stimulated the binding. Ethanol reduced the stimulatory effects of GABA and pentobarbital in a dose-dependent manner, but had no effect on the enhancement of "3"5S-TBPS binding produced by diazepam. "3"5S-TBPS binding to cortical brain membranes was inhibited by the putative Cl"- channel blocking agent DIDS. This inhibitory action of DIDS was significantly, and dose-dependently reduced by ethanol (#<=# 100 mM ethanol). Chronic ethanol ingestion in vivo, which produced tolerance ...
The symmetrical complexes [{sup 99m}Tc][TcN(R{sub 2}PS{sub 2}){sub 2}] [R = CH{sub 3}, CH{sub 2}CH{sub 3}, CH{sub 2}CH{sub 2}CH{sub 3}, CH{sub 2}(CH{sub 3}){sub 2}], and the unsymmetrical complex [{sup 99m}Tc][TcN(Me{sub 2}PS{sub 2})(Et{sub 2}PS{sub 2})] have been prepared, at tracer level, through a two-step procedure involving the preliminary formation of a prereduced technetium nitrido intermediate followed by substitution reaction onto this species by the appropriate dithiophosphinate ligand [R{sub 2}PS{sub 2}]Na. The chemical identity of the resulting complexes have been established by comparison with the corresponding {sup 99}Tc-analogs prepared, at macroscopic level, by reacting the complex [{sup 99}TcNCl{sub 4}] [n-Bu{sub 4}N] (n-Bu = n-butyl) with an excess of ligand in methanol, and characterized by elemental analyses and spectroscopic techniques. The complexes are neutral and lipophilic, and possess a square pyramidal geometry, with an apical Tc N group ...
The symmetrical complexes ["9"9"mTc][TcN(R_2PS_2)_2] [R = CH_3, CH_2CH_3, CH_2CH_2CH_3, CH_2(CH_3)_2], and the unsymmetrical complex ["9"9"mTc][TcN(Me_2PS_2)(Et_2PS_2)] have been prepared, at tracer level, through a two-step procedure involving the preliminary formation of a prereduced technetium nitrido intermediate followed by substitution reaction onto this species by the appropriate dithiophosphinate ligand [R_2PS_2]Na. The chemical identity of the resulting complexes have been established by comparison with the corresponding "9"9Tc-analogs prepared, at macroscopic level, by reacting the complex ["9"9TcNCl_4] [n-Bu_4N] (n-Bu = n-butyl) with an excess of ligand in methanol, and characterized by elemental analyses and spectroscopic techniques. The complexes are neutral and lipophilic, and possess a square pyramidal geometry, with an apical Tc N group and two dithiophosphinate ligands spanning the four positions on the basal plane through the four sulfur atoms of ...
Abstract A series of small phosphazene ligands with pendant 6-phenyl-2,2--bipyridyl moieties, namely L1 [N3P3(OPh)5(OPhbpyPh)], L2 [N3P3(biph)2(OPhbpyPh)2], L3 [N3P3(tBubiph)2(OPhbpyPh)2], L4 [N3P3(biph)2(OPhbpyPh)Cl] and L5 [N3P3(biph)2(OPhbpyPh)(OPh)] [OPhbpyPh = 4-(4-phenoxy)-6-phenyl-2,2--bipyridine, OPh = phenoxy, biph = 2,2--oxybiphenyl and tBubiph = 4,4--di-tert-butyl-2,2--oxybiphenyl], have been used to synthesise the new cyclometallated palladium(II) and platinum(II) complexes [(L1-H)PdCl], [(L1-H)PtCl], [(L1-H)(PdCl)2], [(L3-H)(PdCl)2], [(L4-H)PtCl], [(L5-H)PtCl] and the rhenium(I) complex [L5Re(CO)3Cl]. Single-crystal X-ray diffraction analysis was performed on the free ligand L2 and the palladium complexes [(L1-H)PdCl] and [(L3-H)(PdCl)2]. In both PdII complexes, the metal cent...
In response to a request from DOE-SR, the current state of knowledge of the reactions between TBP and aqueous nitrate solutions is critically reviewed, and recommendations are made for the safe operation of SRS separations equipment in which this combination of chemicals may be present. The existing limits for evaporation are validated. Guidelines are presented for cases in which general limits do not apply. The rate of reaction between nitric acid and TBP appears to be controlled by the rate of TBP hydrolysis. The hydrolysis reaction produces dibutyl phosphate and n-butanol. The hydrolysis rate is a strong function of temperature, and becomes very fast at temperatures in the range 130{degrees} to 150{degrees}C. The resulting n-butanol is volatile at high temperatures, boiling at 117.5{degrees}C, but is also subject to exothermic oxidation by nitric acid or nitrates. If oxidation occurs before the n-butanol evaporates, the heat of oxidation may exceed local cooling by convection. The ...
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a carcinogenic tobacco specific nitrosamine, can be converted to electrophilic diazohydroxide intermediates by metabolic hydroxylation of either the methylene carbon (carbon 4) or the methyl carbon attached to the nitrosamine group. To investigate the relative importance of these two processes in NNK mutagenesis, we synthesized 4,4-dideutero-4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone((4,4,-D2)NNK) and 4-(trideuteromethylnitrosamino)-1-(3-pyridyl)-1-butanone ((CD3) NNK), and evaluated their mutagenic activities in Salmonella typhimurium tester strains. In the presence of Aroclor induced rat liver 9000 g supernatant, NNK and (4,4-D2)NNK had comparable mutagenic activities towards S. typhimurium TA 1535 and TA 100, but (CD3)NNK was inactive in both strains. These results suggest that hydroxylation of the methyl group of NNK is more important than hydroxylation of carbon 4 in its activation to a mutagen. To test the inherent ...
The authors present the results of an investigation of the effect of gamma radiation on the properties of low-molecular moulded polymethyl methacrylates (molecular weight distribution, physico-mechanical properties, resistance to the effects of aqueous media and physiological solution) in the form of copolymers of methyl methacrylate with methyl acrylate (MA) or butyl acrylate (BA) with the brand names Dacryl-4B, Dacryl-2M and Dacryl-4M (4% BA; 2 and 4% MA respectively) having a molecular weight of around 10"5. For comparison, block polymethyl methacrylate with a molecular weight of 3 x 10"6 was used. The results of experiments on the ageing of unirradiated and irradiated specimens in a heated store-room (t = 10 - 20"0C) and at high temperatures (90"0C) are also given. It is shown that irradiation with doses of 2.5 - 20 Mrad leads to radiolysis of the above copolymers, accompanied by destructive processes. Evidence of this is an increase in the polydispersity of ...
The authors present the results of an investigation of the effect of gamma radiation on the properties of low-molecular moulded polymethyl methacrylates (molecular weight distribution, physicomechanical properties, resistance to the effects of aqueous media and physiological solution) in the form of copolymers of methyl methacrylate with methyl (MA) or butyl acrylate (BA) with the brand names Dacryl-4B, Dacryl-2M and Dacryl-4M (4% BA; 2 and 4% MA respectively) having a molecular weight of around 10"5. For comparison, block polymethyl methacrylate with a molecular weight of 3 x 10"6 was used. The results of experiments on the ageing of unirradiated and irradiated specimens in a heated store-room (t = 10 - 20"0C) and at high temperatures (90"0C) are also given. It is shown that irradiation with doses of 2.5-20 Mrad leads to radiolysis of the above copolymers, accompanied by destructive processes. Evidence of this is an increase in the polydispersity of the materials ...
Metal oxide semiconductor (MOS) integrated circuits, with the benefits of low power consumption, represent the state of the art technology for implantable medical devices. Three significant sources of radiation are classified as having the ability to damage or alter the behavior of implantable electronics; Secondary neutron cosmic radiation, alpha particle radiation from the device packaging and therapeutic doses(up to 70 G{gamma}) of high energy radiation used in radiation oncology. The effects of alpha particle radiation from the packaging may be eliminated by the use of polyimide or silicone rubber die coatings. The relatively low incidence of therapeutic radiation incident on an implantable device and the use of die coating leaves cosmic radiation induced secondary neutron single event upset (SEU) as the main pervasive ionising radiation threat to the reliability of implantable devices. A theoretical model which predicts the susceptibility of a RAM cell to ...
Diethyldithiocarbamate (DDTC), a chelating agent, is an active metabolite of disulfiram (Antabus) and is used in the rubber industry. The effect of DDTC on the tissue distribution of "2"0"3Pb was studied in rats. Two groups of rats were given an i.v. injection of 100 #mu#Ci "2"0"3Pb (28.6 nmol/kg b.wt.) as lead acetate. After 10 min one group received 2 mmol/kg b.wt. of DDTC as an i.p. injection. Rats were killed 4 and 72 h after injection of "2"0"3Pb and tissue concentration and excretion of "2"0"3Pb was determined by gamma counting. The brain concentration of "2"0"3Pb in DDTC-treated rats was nine times higher than in controls after 4 h and 14 times higher after 72 h. Treatment with DDTC also increased the lead concentration in fat about seven times at both survival intervals. On the other hand, uptake of "2"0"3Pb in bone was reduced by treatment with DDTC and at 4 h also kidney and blood had a lower concentration of "2"0"3Pb in DDTC-treated rats compared to ...
There are 1.4 Gt (1.5 billion st) of recoverable coal under less than 914 m (3,000 ft) of cover in Colorado in pitching seams. Snowmass Coal Co., in cooperation with the US Department of Energy, introduced the longwall mining method in pitching seams to North America. This venture is a coal mining research program directed toward the profitable production of coal under difficult mining conditions as found in pitching seams of the western US. Snowmass Coal classifies pitching seams into the following categories for longwall on the strike in seams 3 m (10 ft) or less thick: Flat = 0 to 10/sup 0/: Normal continuous mines and shuttle cars work efficiently. Slight = 10/sup 0/ to 22/sup 0/: The maximum pitch that rubber tired equipment will function. Moderate = 22/sup 0/ to 40/sup 0/: The angle of repose of mined coal. Steep = 40/sup 0/ to 60/sup 0/: The limit of safe use of this roof support. Vertical = over 60/sup 0/. The longwall roof support covered here will work in ...
This article described a full-scale green renovation project undertaken by a construction management firm in Newton, Massachusetts. Chapman Construction and Design began renovating its own office building in late 2007 and completed it in September 2008. The firm set out to achieve LEED Platinum certification from the United States Green Building Council. The project involved energy saving modifications to its mechanical systems; replacing plumbing fixtures with high efficiency alternatives to reduce water consumption by at least 40 per cent; installing skylights and additional windows to allow more natural light into the interior space; salvaging doors, lighting, metal studs and masonry whenever possible; and using sustainable products such as recyclable carpets, tiles and low-VOC paint. The main feature of the renovation was a new 47 kW (DC) photovoltaic (PV) solar power array installed on the rooftop. The PV array includes 208 panels and a SunPower SPR-225 system that produces 55,000 ...
BACKGROUND: Denys-Drash Syndrome (DDS) is an uncommon disorder that appears sporadically and in rare cases may be inherited as an autosomal dominant trait It manifests either at birth or within the first year of life and typically consists of the triad of congenital nephropathy, Wilms tumour and intersex disorder. CASE REPORT: A 10 year-old Caucasian girl was referred to the Dental Department, at Glasgow Royal Hospital for Sick Children by her Paediatric Nephrologist Consultant. The patient was being teased by her peers over her markedly discoloured teeth. The dental history revealed that the patient was a regular dental attendee from an early age. She was dentally anxious having only experienced dental treatment under general anaesthesia (GA) when she was 4 years old. Apparently her primary dentition also showed a generalised discolouration. TREATMENT: This consisted of multiple visits for diet analysis and tooth brushing instruction with the use of disclosing tablets. Plaque control ...
Radiation technology offers a very wide scope for utilisation and commercial exploitation in various field. All over the world, this technology is being favourably considered for different applications like radiation sterilisation of medical products, preservation of food by controlling the physiological processes for extending shelf-life and eradication of microbial and insect pests, radiation processing of polymeric materials and treatment of sewage sludge. Bangladesh Atomic Energy Commission has taken radiation processing programmes in a big way right from its inception. This paper describes the studies carried out by various research groups in Bangladesh Atomic Energy Commission mainly using Cobalt-60 gamma radiation. The investigation covers medical sterilisation, food preservation and development and modification of polymeric materials by gamma radiation. Both food preservation and radiation sterilisation of medical products are now being commercially carried out in the Gammatech ...
The objectives of this project are to support the DOE direct coal liquefaction process development program and to improve the useful application of analytical chemistry to direct coal liquefaction process development. Independent analyses by well-established methods will be obtained of samples produced in direct coal liquefaction processes under evaluation by DOE. Additionally, analytical instruments and techniques which are currently underutilized for the purpose of examining coal-derived samples will be evaluated. The data obtained from this study will be used to help guide current process development and to develop an improved data base on coal and coal liquids properties. A sample bank will be established and maintained for use in this project and will be available for use by other researchers. The reactivity of the non-distillable resids toward hydrocracking at liquefaction conditions (i.e., resid reactivity) will be examined. From the literature and data experimentally obtained, ...
The behaviour of the packaging materials under radiation field has a great importance in radiation processing, because, in most cases, they are finally responsible for the preservation of the beneficent changes achieved in irradiated products. For example, in radiation sterilisation and food irradiation, the packages must preserve the sterilisation, respectively the sanitisation. They must preserve also the physical barrier feature. The radiation effects on plastics were extensively studied in the last decades for nuclear industry and more recently for radiation processing. The two major effects of nuclear radiation on polymeric materials are the degradation and cross-linking. The degradation consists in breaking of macromolecules after interaction with nuclear particles, amplified by the free radicals which persist long periods, especially in crystalline polymers. Oxygen could penetrate the sample and interact with free radicals so that the degradation process continues after the ...
LEDF(Large Equipment Dismantling Facility) is the solid waste processing technology development facility that carries out high-volume reduction and low dosage processing. The high-volume reduction processing of the high dose {alpha}-waste configured with combustible waste, pvc and rubber, spent ion exchange resin, and noncombustible waste have been planned the incinerating and melting facility using the in-can type high frequency induction heating in LEDF. This test is intended to clarify the design data. It was confirmed that the incinerating and melting performance, molten solid properties and exhaust gas processing performance with pilot testing equipment and bench scale equipment. The result of this test are as follows. 1. Processing speed is 6.7 kg/h for the combustible waste, 13.0 kg/h for the ion exchange resin, and 30.0 kg/h for the noncombustible waste. For above optimum processing conditions are as follows. Operating temperature is 1000degC for the ...
A plan has been put forth to strategically thin northern California forests to reduce fire danger and improve forest health. The resulting biomass residue, instead of being open burned, can be converted into ethanol that can be used as a fuel oxygenate or an octane enhancer. Economic potential for a biomass-to-ethanol facility using this softwood biomass was evaluated for two cases: Stand-alone and co-located. The co-located case refers to a specific site with an existing biomass power facility owned by Wheelabrator Environmental Systems Inc. near Martell, California. A two-stage dilute acid hydrolysis process is used for the production of ethanol from softwoods, and the residual lignin is used to generate steam and electricity. For a plant processing 800 dry tonnes per day of feedstock, the co-located case is an economically attractive concept. Total estimated capital investment is approximately $ 70 million for the co-located case. The resulting internal rate of return is about 24% ...
This thesis deals with the evaluation of Solar Grade Silicon (SoG-Si) purified by different techniques, and also the fabrication and characterization of high efficiency and advanced bifacial solar cells. In the beginning of Chapter 1, various SoG-Si production methods relevant for this work are qualitatively described. The three feedstock materials used in this work are from the Fluidized Bed Reactor (FBR) process, metallurgical feedstock-I and feedstock-II process. In metallurgical feedstock-I, the lifetime of the minority charge carriers in multicrystalline silicon (mc-Si) samples at the grain boundaries are found to be higher than the grains themselves possibly due to lower resistivities in the grain boundaries. The efficiency of the best solar cell obtained using the mc-Si metallurgical feedstock-I is 16.1%. It has been identified that the fast light induced degradation, whose magnitude is lower than that of a reference cell suggests the formation of a B-metal complex in the SoG-Si ...
Soil gas, soil, and water were assessed for organic and inorganic constituents at the former 19th Street landfill at Fort Gordon, Georgia, from February to September 2010. Passive soil-gas samplers were analyzed to evaluate organic constituents in the hyporheic zone and flood plain of a creek and soil gas within the estimated boundaries of the former landfill. Soil and water samples were analyzed to evaluate inorganic constituents in soil samples, and organic and inorganic constituents in the surface water of a creek adjacent to the landfill, respectively. This assessment was conducted to provide environmental constituent data to Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. The passive soil-gas samplers deployed in the water-saturated hyporheic zone and flood plain of the creek adjacent to the former landfill indicated the presence of total petroleum hydrocarbon (TPH) and octane above method detection levels ...