scholarly journals On In-Situ Disposal of ChNPP Facilities

2020 ◽  
pp. 64-68
Author(s):  
S. Paskevych ◽  
Yu. Olkhovyk
Keyword(s):  
Regulatory Control ◽  
Potential Hazard ◽  
Exclusion Zone ◽  
Safety Level ◽  
Strong Earthquakes ◽  
Reactor Graphite ◽  
Vrancea Zone ◽  
Time Required ◽  
Probabilistic Nature

The paper considers the possibility of applying in-situ disposal practice for Chornobyl exclusion zone facilities, in particular: ChNPP-1-3 that are under decommissioning, Shelter, RWDS ChNPP Stage III and RWDS Pidlisny. It was concluded that these facilities would not reach safety level over the next 300 years sufficient for clearance from regulatory control. In-situ disposal of ChNPP-1-3 would lead to a potential hazard related to a large amount of irradiated reactor graphite. Artificial barriers of concrete and bulk clay will not provide isolation of radionuclides, primarily radiocarbon, from the environment. The paper considers possible natural factors, the effect of which for the time required for the decay of radionuclides to acceptable level, can lead to destruction of surface storage facilities on ChNPP site. Such factors are as follows: probable transformation of Pripyat river valley; seismic influence related to both strong earthquakes in the Vrancea Zone (Romania) and the influence of local seismic centre. It raises issues connected with considering climate change, duration of and change in climate cycles for safety justification of in-situ disposal practices for ChNPP facilities. It was concluded that at this time it is impossible, to prove safety of surface burial on ChNPP site for the period of tens of thousands of years, since a number of external factors have probabilistic nature.

In situ enzymatic removal of orthophosphate by the nucleoside phosphorylase catalyzed phosphorolysis of nicotinamide riboside

1982 ◽  
Vol 60 (9) ◽  
pp. 917-921 ◽  
Author(s):  
John W. Shriver ◽  
Brian D. Sykes
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nucleoside Phosphorylase ◽  
Nicotinamide Riboside ◽  
Time Required ◽  
Removal System ◽  
Nuclear Magnetic

An enzymatic orthophosphate removal system is described which can be effectively used to continuously remove orthophosphate from biochemical samples. The phosphorolysis of nicotinamide riboside is catalyzed by calf spleen nucleoside phosphorylase to give ribose-1-PO4 and nicotinamide along with a proton. At pH 8 the production of ribose-1-PO4 from orthophosphate is essentially quantitative. This reaction can be monitored optically or by 31P nuclear magnetic resonance (NMR). Equations are given for determining the time required to remove a given amount of phosphate from a typical NMR sample with a known amount of nucleoside phosphorylase. The effects of a competing orthophosphate-producing reaction are considered.

Fate and transport of faecal contamination microbial indicators, pathogenic protozoa and Campylobacter in the artificially recharged fractured aquifer of Salento, Italy

2008 ◽  
Vol 57 (6) ◽  
pp. 849-856 ◽  
Author(s):  
R. La Mantia ◽  
C. Masciopinto ◽  
C. Levantesi ◽  
V. Tandoi
Keyword(s):  
Pathogenic Bacteria ◽  
Fate And Transport ◽  
Fractured Aquifer ◽  
Specific Detection ◽  
Microbial Indicators ◽  
Faecal Contamination ◽  
Time Required ◽  
Indicators Of Faecal Contamination ◽  
Campylobacter Spp

The study investigates the fate and transport of microorganisms introduced by artificial groundwater recharge at the Nardò fractured aquifer in Salento, Italy. Microbial indicators of faecal contamination, parasitic protozoa (Giardia and Cryptosporidium) and pathogenic bacteria (Campylobacter spp.), were monitored into injected water and groundwater to test the efficiency of the “natural disinfection” into the fractured aquifer. A remarkable decrease of microbial indicators and pathogens was observed suggesting that pathogens removal or inactivation may be possible during water flow in fractured aquifer. The recently described PNA probe CJE195 (Lehtola et al. 2005) was utilised for the rapid and specific detection of Campylobacter spp. by fluorescence in situ hybridization (FISH) after enrichment. FISH results were consistent with those of traditional cultural method (ISO 17995) applied in parallel: time required for Campylobacter identification was reduced of 4 days.

In-Situ, Time Resolved, Kinetics of Reactions in Co-Ge thin Films

1991 ◽  
Vol 237 ◽  
Author(s):  
R. M. Walser ◽  
Byung-Hak Lee ◽  
Alaka Valanju ◽  
Winston Win ◽  
M. F. Becker
Keyword(s):  
Depth Profiling ◽  
Laser Interferometry ◽  
Semiconductor Interface ◽  
Time Resolved ◽  
Interface Reactions ◽  
Valuable Adjunct ◽  
Diffusion Controlled ◽  
Sputter Deposited ◽  
Time Required

ABSTRACTWe report the first kinetic study of metal-semiconductor interface reactions using in-situ, time resolved, laser interferometry. Diffusion couples with Co/Ge thicknesses of 1500 Å/1500 Å were sputter deposited on silicon wafers, and vacuum-annealed at temperatures between 300°C-400°C. Under these conditions polycrystalline CoGe was expected to form [1]. Real time laser (HeNe 6328 Å) interferograms for each anneal were recorded in-situ. These data were supplemented by information from AES and X-ray.For temperatures below 400°C the diffusion controlled formation of CoGe was observed. The composition was confirmed by Auger depth profiling that showed uniform Co and Ge concentrations when the reaction went to completion. The well defined interferences fringes were formed by the dissolution of amorphous Ge. The activation energy = 1.6 eV for the formation of CoGe were determined with precision from the temperature dependence of the time required to anneal the fixed λ/4 distance between adjacent minima and maxima of the interferogram. We discuss the evidence for formation of an intermediate Co-rich compound following the initial diffusion of Co into Ge. The results of these experiments indicate that optical interferometry will be a valuable adjunct to other techniques used to study metal-semiconductor interface reactions.

EFFECTS OF GROWING SEASON SOIL TEMPERATURE, MOISTURE, AND NH4-N ON SOIL NITROGEN

1974 ◽  
Vol 54 (4) ◽  
pp. 403-412 ◽  
Author(s):  
C. A. CAMPBELL ◽  
D. W. STEWART ◽  
W. NICHOLAICHUK ◽  
V. O. BIEDERBECK
Keyword(s):  
Quantitative Relationship ◽  
Growing Season ◽  
Stepwise Multiple Regression ◽  
Soil N ◽  
N Transformations ◽  
Temperature Changes ◽  
Diurnal Patterns ◽  
Multiple Regression Technique ◽  
Time Required

Wood Mountain loam was wetted with water or (NH4)2SO4 solution to provide a factorial combination among three moisture and three NH4-N levels. Samples in polyethylene bags were incubated at 2.5-cm depths in fallow, and in an incubator that simulated the diurnal patterns of temperature fluctuation recorded in the field. During the growing season, treatments were sampled regularly for moisture, NO3− and exchangeable NH4-N. Similar determinations were made on in situ samples taken in fallow Wood Mountain loam. The incubator simulated the effects of growing season temperatures on soil N transformations satisfactorily. Pronounced increases or decreases in temperature led to flushes in N mineralization. However, in the 1972 growing season, temperature was suboptimal and temperature changes were generally small. Consequently, when a stepwise multiple regression technique was used to analyze the data, neither ammonification nor nitrification showed a quantitative relationship to temperature. Comparison of the nitrification occurring in laboratory-incubated soils with that occurring in situ led to the conclusion that 70 to 90% of the NO3-N produced in surface soil resulted from wetting and drying. Estimates of potentially ammonifiable soil N(No) and its rate of mineralization (k) were derived from cumulative ammonification by assuming that the laws of first-order kinetics were applicable. In the 10, 15, and 20% moisture treatments the average No was 27, 41, and 82 ppm, respectively. Under the conditions of this study, the time required to mineralize half of No was about 7 wk.

scholarly journals Principal Component Gradiometer technique for removal of spacecraft-generated disturbances from magnetic field data

2020 ◽  
Author(s):  
Ovidiu Dragoş Constantinescu ◽  
Hans-Ulrich Auster ◽  
Magda Delva ◽  
Olaf Hillenmaier ◽  
Werner Magnes ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Principal Component ◽  
Field Measurements ◽  
Magnetic Field Data ◽  
Service Oriented ◽  
Sensor Configuration ◽  
Time Required ◽  
First Time ◽  
The Magnetic Field

Abstract. In situ measurement of the magnetic field using space borne instruments requires either a magnetically clean platform and/or a very long boom for accommodating magnetometer sensors at a large distance from the spacecraft body. This significantly drives up the costs and time required to build a spacecraft. Here we present an alternative sensor configuration and an algorithm allowing for ulterior removal of the spacecraft generated disturbances from the magnetic field measurements, thus lessening the need for a magnetic cleanliness program and allowing for shorter boom length. The proposed algorithm is applied to the Service Oriented Spacecraft Magnetometer (SOSMAG) onboard the Korean geostationary satellite GeoKompsat-2A (GK2A) which uses for the first time a multi-sensor configuration for onboard data cleaning. The successful elimination of disturbances originating from several sources validates the proposed cleaning technique.

Improved Filter Method for Urine Sediment Detection of Urothelial Carcinoma by Fluorescence In Situ Hybridization

2007 ◽  
Vol 131 (10) ◽  
pp. 1574-1577 ◽  
Author(s):  
Isabelle Meiers ◽  
Harpreet Singh ◽  
Deloar Hossain ◽  
Kevin Lang ◽  
Lina Liu ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Urothelial Carcinoma ◽  
Urine Cytology ◽  
Filter Method ◽  
Urine Sediment ◽  
Specific Test ◽  
Significant Difference ◽  
Time Required

AbstractContext.—Fluorescence in situ hybridization (FISH) of voided urine sediment is a sensitive and specific test for the detection of urothelial carcinoma. The time required for slide preparation using the conventional cytospin method is lengthy.Objective.—To present an alternative to the conventional cytospin method.Design.—We compared the results of an improved filter monolayer method with published results of the conventional cytospin method. A total of 624 patients with cytology and FISH analyses were followed with cystoscopy and/ or bladder biopsy. Fluorescence in situ hybridization analysis was performed on 624 cases using fluorescence-labeled probes to the pericentromeric regions of chromosomes 3, 7, and 17 and band 9p21; cytology was also performed in all cases.Results.—A total of 217 (34.7%) of 624 patients had follow-up bladder biopsies, and 170 of these (78.3%) had urothelial carcinoma. The sensitivity for cancer detection was higher for FISH than for urine cytology (92.9% [158/ 170] for FISH vs 72.9% [124/170] for urine cytology, P = <5%). The specificity was equivalent for FISH and urine cytology (97.5% [443/454] for FISH vs 92.2% [419/454] for cytology). The sensitivity for FISH was better (92.9% vs 81%), and there was no significant difference in specificity (97.5% vs 96%) between the filter method and the conventional cytospin method. Unlike the conventional cytospin method, the filter method did not require multiple centrifugation and decantation steps or investment in dedicated equipment.Conclusions.—The improved filter method was faster, easier, and less expensive than published results with the conventional cytospin method with better sensitivity and equivalent specificity.

New chalcogenide glass chemical sensors for S2- and dissolved H2S monitoring

2003 ◽  
Vol 47 (2) ◽  
pp. 135-140 ◽  
Author(s):  
M. Miloshova ◽  
D. Baltes ◽  
E. Bychkov
Keyword(s):  
Process Control ◽  
Chalcogenide Glass ◽  
Chemical Sensors ◽  
Industrial Process ◽  
In Situ Monitoring ◽  
Potential Hazard ◽  
Reliable Monitoring ◽  
Industrial Process Control ◽  
Monitoring Devices

A non-optimised treatment of wastewaters containing organic and biological substances is very often accompanied by an accidental emanation of hydrogen sulphide H2S and therefore leads (i) to an undesirable odour in the vicinity of water treatment plants, and (ii) to a potential hazard for the neighbouring population. Fast, sensitive and reliable monitoring devices are hence of significant importance. Chalcogenide and chalcohalide glasses are new promising membrane materials for detection of heavy metal ions and toxic anions and particularly well adapted for continuous in situ monitoring and industrial process control. In the present paper, we will discuss analytical characteristics of new chalcogenide glass chemical sensors for detection of S2− and dissolved H2S, which allow reliable process control to be carried out at natural pH of wastewaters.

Quantifying percentage cover of subtidal organisms on rocky coasts: a comparison of the costs and benefits of standard methods

2005 ◽  
Vol 56 (6) ◽  
pp. 865 ◽  
Author(s):  
S. P. Drummond ◽  
S. D. Connell
Keyword(s):  
Benthic Algae ◽  
Costs And Benefits ◽  
Percentage Cover ◽  
Sessile Invertebrates ◽  
Time Required ◽  
Taxonomic Groups ◽  
The Cost ◽  
Regular Arrays ◽  
Laboratory Time

This study compares the cost (time and funds) and benefits (precision and accuracy) of methods commonly used to estimate percentage cover of sessile marine organisms. We applied nine methods to morphological groups of benthic algae and broad taxonomic groups of sessile invertebrates; including varying the intensity of sampling (25 v. 50 v. 100 point-intercepts), random v. regular arrays, in situ v. laboratory v. photographic sampling v. computer digitising. We detected little to no difference in estimates of percentage cover among methods, indicating that accuracy is unlikely to be an important issue that distinguishes methods. Precision was generally unaffected by the intensity of sampling within quadrats (25 v. 50 v. 100 point-intercepts) or between environments (in situ v. on photographs v. within the laboratory) and appeared to be of secondary concern to decisions about replication. Computer digitising (estimates of surface area of each taxon) provided the least precise estimates and did not justify the additional laboratory time required to process them. Depending on whether field expenses or laboratory expenses are of the greatest concern, the techniques that permit the greatest coverage of area (greatest replication) are likely to produce the most representative (accurate) and reliable (precise) estimates.

Growth rate observation from the moss-built Checa travertine terrace, central Spain

1986 ◽  
Vol 123 (3) ◽  
pp. 279-286 ◽  
Author(s):  
Ruud Weijermars ◽  
Carla W. Mulder-Blanken ◽  
Jaap Wiegers
Keyword(s):  
Growth Rate ◽  
Surface Area ◽  
Green Algae ◽  
Central Spain ◽  
Blue Green Algae ◽  
Artificial Surfaces ◽  
Depositional Rate ◽  
Bryum Pseudotriquetrum ◽  
Time Required

AbstractIn situ observations of fossil and living specimens of the calcicolous mosses Bryum pseudotriquetrum, Cratoneuron commutatum and Catoscopium nigritum revealed very fast calcite depositional rates. Rhythmic layering in the fossil mosses corresponding with the seasonal climatic cycle suggests that the moss curtain occupied by these three mosses maintains the deposition of spongeous travertine layers at a mean rate of 4 cm a−1. A mean depositional rate of 4.2 cm a−1 may be calculated from measurements of the loss of bicarbonate from the springwater after it percolated through the moss curtain. These rates suggest that the 8 m high travertine terrace of Checa with a surface area of 800 m2 did not exist two millennia ago.Mosses could be put to man's use for creating natural overgrowths on artificial surfaces, an idea based on an allusion by Wallner. He observed that the thread-forming, blue-green algae Vaucheria builds travertine deposits at an annual rate of 0.7–1.4 cm. We observed that the mosses Cratoneuron commutatum and Bryum pseudotriquetrum may form spongeous travertine layers at respective maximum rates of 11 and 14 cm a−1. This would reduce the time required to build natural overgrowths on artificial objects to a practical period of months.

On Pressure Pulse Techniques for Testing Low Permeability Geological Materials and Formations

2003 ◽  
Vol 807 ◽  
Author(s):  
M. Zhang ◽  
M. Takeda
Keyword(s):  
Pressure Pulse ◽  
Low Permeability ◽  
Specific Storage ◽  
Geological Materials ◽  
Geological Formation ◽  
Time Required ◽  
Practical Implications ◽  
Significant Underestimation

ABSTRACTThe accurate hydraulic characterization of low permeability geological materials and formations has important practical implications, such as the geological disposal of radioactive nuclear waste. In this paper, we discuss pressure pulse techniques, which are methods that are commonly adopted both in the laboratory and in situ for testing low permeability geological materials and formations. The results obtained in this study illustrate that: 1) the use of nominal values for water compressibility will lead to significant underestimation of permeability from the pressure pulse tests; 2) specific storage is also an important parameter that should be evaluated simultaneously with permeability; 3) to shorten the time required to measure low permeability in the laboratory, it is advisable to use disk-shaped specimens; 4) when a geological formation is anisotropic, the value of permeability calculated using an isotropic model is between the maximum and minimum permeabilities of the geological formation; 5) the values of permeability and specific storage derived from an in situ pressure pulse test may only reflect the hydraulic properties of the domain closely surrounding the test well. Caution should be exercised when interpreting data derived from the pressure pulse tests for the purpose of safety assessment.

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