scholarly journals Investigation of the liquid low-level waste evaporator steam coil failure and supporting laboratory studies

10.2172/95185 ◽  
1995 ◽  
Author(s):  
S.J. Pawel ◽  
J.R. Keiser ◽  
H.F. Longmire
Author(s):  
Fong-In Chou ◽  
Chia-Chin Li ◽  
Tzung-Yuang Chen ◽  
Hsiao-Wei Wen

This research addresses the potential of microbial implications in bentonite for use as a buffer and backfill material in final disposal site for low-level radioactive waste (LLRW) in Taiwan, where has a special island-type climate. Microbe activities naturally present in this site were analyzed, and buffer materials (BM) consisted of 100%, 70% or 50% bentonite were prepared for laboratory studies. A total of 39 microbial strains were isolated, and the predominant strains included four bacterial, one yeast and four fungal strains. Growth inhibition was not detected in any tested strain cultured in a radiation field with a dose rate of 0.2 Gy/h. Most of the isolated strains grew under a dose rate of 1.4 Gy/h. The D10 values of the tested strains ranged from 0.16 to 2.05 kGy. The mycelia of tested fungal strains could spread over 5 cm during six months of inoculation in BM. The spreading activity of the tested bacteria was less than that of the fungi. Moreover, biofilms were observed on the surfaces of the BM. Since a large and diverse population of microbes is present in Taiwan, microbes may contribute to the mobilization of radionuclides in the disposal site.


1997 ◽  
Vol 129 (3) ◽  
pp. 519-536 ◽  
Author(s):  
George T. Harvey

AbstractLaboratory studies of seven North American Choristoneura species and two subspecies from widely distributed locations demonstrate the low level of genetic separation among them. No differences were found in numbers (n = 30) or morphology of chromosomes among members of the group or in any of the hybrids examined. High levels of mating success were obtained in all inter se matings as well as in crosses and back-crosses. However, mating success was greater for crosses within host type and within pheromone type than for crosses between types. Viability and fertility were similar in all the hybrids and close to those of the inter se progenies. Mean weights of initial eggs varied by a factor of 2 from the lowest (C. pinus Freeman) to the highest (C. lambertiana ponderosana Obraztsov). Mean weights of initial eggs produced by hybrids were generally close to those of the parental species. However, when one parent was C. fumiferana (Clem.), mean weights of initial eggs were either much larger (male C. fumiferana) or much smaller (female C. fumiferana) than either parental type. These differences could affect survival of some progeny under harsh conditions. This evidence supports other studies in indicating that C. fumiferana is genetically distinct from other species in this group.


2020 ◽  
pp. 48-51
Author(s):  
R. T. Kuliyev ◽  
T. E. Kenzhebayev ◽  
S. N. Bekisheva ◽  
L. K. Mamyrova ◽  
Z. T. Yesembekova

Relevance. According to the results of numerous scientific and laboratory studies, both lack of fatness and excessive obesity of livestock reduce the quality of meat and are the result of imperfect technology of growing and fattening animals or a low level of breeding and irrational use of feed.Methods. Scientific and production experiments were carried out in the Tau Samal LTD Company LLP and the Plemzavod Almaty SEC Almaty region. The dynamics of live weight, fattening and slaughter qualities of young dairy and dairy and beef cattle during the periods of growing and fattening were studied.Results. Gobies of experimental groups of different genotypes, which received feed additives in addition to the main diet, in terms of live weight, fattening qualities, growth and development rates, total and average daily gains, morphological and chemical compositions and energy value of meat favorably differed from uniform age counterparts from the control groups.


1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.


2006 ◽  
Vol 76 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Yukari Egashira ◽  
Shin Nagaki ◽  
Hiroo Sanada

We investigated the change of tryptophan-niacin metabolism in rats with puromycin aminonucleoside PAN-induced nephrosis, the mechanisms responsible for their change of urinary excretion of nicotinamide and its metabolites, and the role of the kidney in tryptophan-niacin conversion. PAN-treated rats were intraperitoneally injected once with a 1.0% (w/v) solution of PAN at a dose of 100 mg/kg body weight. The collection of 24-hour urine was conducted 8 days after PAN injection. Daily urinary excretion of nicotinamide and its metabolites, liver and blood NAD, and key enzyme activities of tryptophan-niacin metabolism were determined. In PAN-treated rats, the sum of urinary excretion of nicotinamide and its metabolites was significantly lower compared with controls. The kidneyα-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) activity in the PAN-treated group was significantly decreased by 50%, compared with the control group. Although kidney ACMSD activity was reduced, the conversion of tryptophan to niacin tended to be lower in the PAN-treated rats. A decrease in urinary excretion of niacin and the conversion of tryptophan to niacin in nephrotic rats may contribute to a low level of blood tryptophan. The role of kidney ACMSD activity may be minimal concerning tryptophan-niacin conversion under this experimental condition.


1996 ◽  
Vol 1 (3) ◽  
pp. 166-179 ◽  
Author(s):  
Bo Molander ◽  
Lars Bäckman

Highly skilled miniature golf players were examined in a series of field and laboratory studies. The principal finding from these studies is that young and young adult players (range = 15-38 years) score equally well or better in competition than in training whereas older adult players (range = 46-73 years) perform worse in competitive events than under training conditions. It was also found that the impairment in motor performance on the part of the older players is associated with age-related deficits in basic cognitive abilities, such as memory and attention. These results support the hypothesis that older players may be able to compensate for age-related deficits under relaxed conditions, but not under conditions of high arousal. The possibility of improving the performance of the older players in stressful situations by means of various intervention programs is discussed.


2017 ◽  
Vol 7 (1) ◽  
pp. 28-41 ◽  
Author(s):  
Robert J. de Boer ◽  
Karel Hurts

Abstract. Automation surprise (AS) has often been associated with aviation safety incidents. Although numerous laboratory studies have been conducted, few data are available from routine flight operations. A survey among a representative sample of 200 Dutch airline pilots was used to determine the prevalence of AS and the severity of its consequences, and to test some of the factors leading to AS. Results show that AS is a relatively widespread phenomenon that occurs three times per year per pilot on average but rarely has serious consequences. In less than 10% of the AS cases that were reviewed, an undesired aircraft state was induced. Reportable occurrences are estimated to occur only once every 1–3 years per pilot. Factors leading to a higher prevalence of AS include less flying experience, increasing complexity of the flight control mode, and flight duty periods of over 8 hr. It is concluded that AS is a manifestation of system and interface complexity rather than cognitive errors.


Sign in / Sign up

Export Citation Format

Share Document