scholarly journals Высокостабильный источник спектральных линий

2019 ◽  
Vol 126 (4) ◽  
pp. 528
Author(s):  
В.К. Битюков ◽  
Р.А. Горбунов ◽  
Д.С. Симачков ◽  
А.В. Фрунзе
Keyword(s):  
Hollow Cathode ◽  
Spectral Lines ◽  
Technical Solution ◽  
Metrological Analysis ◽  
Long Term Stability ◽  
Long Time ◽  
Stable Source ◽  
High Level ◽  
Experimental Bench

In spectroscopy, hollow cathode lamps are subject to increased requirements on radiation parameters. In order to perform verification of such lamps a highly stable source of spectral lines is needed, the intensity of which on the spectral lines will remain unchanged (≤1%) for a long time. A solution to this problem is proposed and a scheme of an experimental bench for a hollow cathode lamp with a negative feedback loop is presented. The developed device is used in control circuit, which is a highly stable source of spectral lines and a specialized power supply unit. The results of the experimental study along with metrological analysis are presented. The proposed technical solution in terms of developing a stable source of spectral lines made it possible to obtain a high level of both short-term and long-term stability of the spectral lines.

Low Alkaline Cement Used in the Construction of a Gallery in the Horonobe Underground Research Laboratory

2010 ◽  
Author(s):  
Masashi Nakayama ◽  
Haruo Sato ◽  
Yutaka Sugita ◽  
Seiji Ito ◽  
Masashi Minamide ◽  
...  
Keyword(s):  
Fly Ash ◽  
Research Laboratory ◽  
Concrete Lining ◽  
Energy Agency ◽  
Tunnel Support ◽  
Long Term Stability ◽  
Alkaline Conditions ◽  
High Level ◽  
Underground Research Laboratory

In Japan, any high level radioactive waste (HLW) repository is to be constructed at over 300 m depth below surface. Tunnel support is used for safety during the construction and operation, and shotcrete and concrete lining are used as the tunnel support. Concrete is a composite material comprised of aggregate, cement and various admixtures. Low alkaline cement has been developed for the long term stability of the barrier systems whose performance could be negatively affected by highly alkaline conditions arising due to cement used in a repository. Japan Atomic Energy Agency (JAEA) has developed a low alkaline cement, named as HFSC (Highly Fly-ash Contained Silicafume Cement), containing over 60 wt% of silica-fume (SF) and fly-ash (FA). HFSC was used experimentally as the shotcrete material in construction of part of the 140m deep gallery in the Horonobe Underground Research Laboratory (URL). The objective of this experiment was to assess the performance of HFSC shotcrete in terms of mechanics, workability, durability, and so on. HFSC used in this experiment is composed of 40 wt% OPC (Ordinary Portland Cement), 20 wt% SF, and 40 wt% FA. This composition was determined based on mechanical testing of various mixes of the above components. Because of the low OPC content, the strength of HFSC tends to be lower than that of OPC. The total length of tunnel using HFSC shotcrete is about 73 m and about 500 m3 of HFSC was used. The workability of HFSC shotcrete was confirmed in this experimental construction.

Dose-Dependence of Pb-Ion Implantation Damage in Zirconolite, Hollandite, and Zircon

1981 ◽  
Vol 11 ◽  
Author(s):  
T. J. Headley ◽  
G. W. Arnold ◽  
C. J. M. Northrup
Keyword(s):  
Radiation Damage ◽  
Structural Damage ◽  
Accelerated Aging ◽  
Dose Dependence ◽  
High Level Waste ◽  
Long Term Stability ◽  
Waste Forms ◽  
Recent Approach ◽  
High Level

The long-term stability of nuclear waste forms is an important consideration in their selection for safe disposal of radioactive waste. Stability against long-term radiation damage is particularly difficult to assess by short-term laboratory experiments. Much of the displacement damage in high-level waste forms will be generated by heavy recoil nuclei emitted during the α-decay process of long-lived actinide elements. Hence, an accelerated aging test which reliably simulates the α-recoil damage accumulated during thousands of years of storage is desirable. One recent approach to this simulation is to implant the waste form with heavy Pb-ions.I- 6 If the validity of this approach is to be fully assessed, two important questions which have not yet been investigated must be answered.(1) Is the structural damage, including cumulative effects, similar for irradiation by Pb-ions and a-recoil nuclei in a given material? (2) Is the dose-dependence of the accumulated damage similar? The purpose of this investigation was to assess the extent of these similarities in selected materials. We utilized transmission electron microscopy (TEM) to characterize the radiation damage and measure its dose-dependence.

Concrete with Crystalline Admixture for Ventilated Tunnel against Moisture

2016 ◽  
Vol 677 ◽  
pp. 108-113 ◽  
Author(s):  
Jiří Pazderka
Keyword(s):  
Masonry Structure ◽  
Subsurface Water ◽  
Technical Solution ◽  
Air Humidity ◽  
Structure Surface ◽  
Additional Protection ◽  
Long Time ◽  
Concrete Blocks ◽  
High Level ◽  
Ground Part

The paper deals with the use of concrete with crystalline admixture for special remedial structure which is exposed to intensive ground moisture and high level of air humidity. Additional protection of ground part of older buildings against subsurface water and ground moisture is one of the most important measures to ensure their long-time durability and satisfactory user properties. One of the most used remediation method are the air ducts which principle is to enable air flow along the moist structure surface to allow the sufficient evaporation of moisture from the structure. This group of methods includes also the ventilated underground tunnel along the perimeter walls. Presently the ventilated tunnels are designed as masonry structure whose durability in contact with the ground moisture is limited. The paper introduces a new technical solution of this method based on the special shaped concrete blocks whose durability is ensured by using of concrete with crystalline admixture. The waterproofing effect of the crystalline admixture is declared by the results of laboratory tests (in comparison with efficiency of crystalline coating).

scholarly journals Analytical capabilities of a «Grand» spectrometer in analysis of solutions using inductively coupled plasma

2019 ◽  
Vol 85 (1II)) ◽  
pp. 82-85 ◽  
Author(s):  
O. V. Pelipasov ◽  
R. A. Lokhtin ◽  
V. A. Labusov ◽  
N. G. Pelevina
Keyword(s):  
Inductively Coupled Plasma ◽  
Microwave Plasma ◽  
Internal Standard ◽  
Plasma Generator ◽  
Atomic Emission ◽  
Spectral Lines ◽  
Term Stability ◽  
Inductively Coupled ◽  
Long Term Stability

It has been shown that «Grand» spectrometers based on a hybrid assembly of BLPP-2000 photodetector arrays produced by «VMK-Optoélektronika» can be used for atomic emission spectral analysis of solutions using inductively coupled plasma atomic emission spectroscopy (ICP-AES). For the prototype of a «Grand-ICP» spectrometer consisting of «Grand» spectrometer, microwave plasma generator, and RF (radiofrequency) generator, the following analytical characteristics were determined: element detection limit, long-term stability, linear ranges of calibration graphs for several elements, and optimal operating parameters of the microwave generator. The linear concentration range of analyte elements is 105when using a single analytical line of the element. The long-term stability is less than 2% in 6 h without using an internal standard. The detection limits are comparable to those of modern ICP spectrometers with an axial plasma survey and lie in a range of sub-microgram per liter. It has been found that the effect of superposition of the spectral lines of the plasma background, for example, OH molecular lines or others, on the analyte lines can be eliminated by subtracting the blank sample spectrum from the analyte spectrum using Atom software. The analytical characteristics of the spectrometer allow the use of the device both for developing new ICP- based systems and restoring the performance of defective ICP spectrometers.

Technical Challenges Facing Regulators–Assessment of Long-Term Materials Performance

1987 ◽  
Vol 112 ◽  
Author(s):  
Kenneth W. Stephens
Keyword(s):  
Real Time ◽  
Waste Disposal ◽  
Time Frame ◽  
High Level Waste ◽  
Short Term ◽  
Long Time ◽  
Computer Codes ◽  
High Level ◽  
Term Data

AbstractFor a number of years, nuclear regulators have grappled with difficult questions such as: “How safe is safe enough?” Such issues take on new dimensions in the long time-frame of high-level waste disposal.Many of the challenges facing regulators involve assessment of long-term materials performance. Because real-time experiments cannot be conducted, it is necessary to rely extensively on modeling. This raises issues regarding the extent to which long-term extrapolations of short-term data are justified, the question of how closely models must represent reality to be trusted, and practical matters such as methods for validating unique computer codes.Issues such as these illustrate how regulators must make decisions in a climate of uncertainty. Methods used by non-technical disciplines to make decisions under uncertainty have been examined and offer solutions for regulators and licensees alike.

scholarly journals Application of Bio-Oss in tissue regenerative treatment prior to implant installation: literature review

2019 ◽  
Vol 22 (2) ◽  
pp. 147-154
Author(s):  
Alessandra De Carvalho Moreira ◽  
Jhenifer Rodrigues Silva ◽  
Renata De Paula Samico ◽  
Gabriela Nogueira de Melo Nishioka ◽  
Renato Sussumu Nishioka
Keyword(s):  
Literature Review ◽  
Bone Graft ◽  
Bone Substitute ◽  
Survival Rates ◽  
Natural Mineral ◽  
Beneficial Effects ◽  
Long Term Stability ◽  
Implant Placement ◽  
High Level

Objetivo: Bio-Oss is a xenogene bone graft in which all organic components are removed while retaining their natural mineral architecture. Therefore, the aim of this study was to evaluate, through a literature review, the benefits of using Bio-Oss for tissue regenerative treatment prior to implant placement. Material and Methods: a search was performed in Pubmed (Medline) in order to identify articles published in English between January 1, 2000 and June 31, 2018, where the Bio-Oss graft was used prior to implantation of implants in humans. A total of 40 studies were selected for detailed analysis. From this analysis, 18 articles were identified for inclusion in this review. Results: the articles analyzed in the review showed several beneficial effects of this xenograft, such as: positive osteoconductive properties, recovery of bone heights at sites with severe atrophies, slow xenograft reabsorption suggesting long term stability, survival rates and success of implants placed in grafted sites ranging from 91 to 100% in several studies. Conclusion: the use of bio-oss as a bone substitute is a viable alternative in the placement before dental implants, being used in clinical practice and with proved efficacy in several studies, due to its similarity with the bone and its high level of osteoconductivity.KeywordsBio-Oss; Bone Graft; Implants.

scholarly journals Psychological studies of stress experienced by seamen during a long-distance sea voyage#

2020 ◽  
Vol 4 (1) ◽  
pp. 049-054
Author(s):  
Plopa Mieczysław
Keyword(s):  
Stress Conditions ◽  
Stress Process ◽  
Long Distance ◽  
Personality Dimension ◽  
Difficult Situation ◽  
Long Time ◽  
Family Variables ◽  
High Level

The issues investigated in the current study pertain to selected psychological aspects of human functioning in long-term stress conditions. Results of the analyses performed in this study have submitted evidence to confirm the hypothesis in which it is stated that staying on the sea for a long time is a difficult situation which contributes - to a greater or smaller extent - to starting the stress process in sailors. The role of interpersonal competencies that has been found most distinct; high level of this variable contributed to reducing both anxiety and the feeling of loneliness. It has been evidenced in the research that the skill of good functioning in varied social groups, which results from high level of development of several traits including: openness, spontaneity, responsibility, and sensitivity, becomes particularly important in long-term difficult situations in which there is little possibility of eliminating the real menace. Another conclusion to be inferred from the research is the one confirming the theoretical suggestion in which the importance of ‘ego strength’ in modifying the course of stress process is emphasised. This personality dimension has turned out to constitute the factor capable of protecting an individual against increase in both anxiety states and the feeling of loneliness during sea isolation. Another issue considered in the current study pertains to defining the role of ‘family variable’ in mediating the course of stress process under conditions of long-term task isolation. The analyses have confirmed the hypothesis in which it was assumed that sailors functioning in family systems characterised by high level of integration and quality, experience lower emotional costs during a voyage. Generally, it may be claimed that - according to the research results of the study - ‘family variables’ may constitute a significant predictor of both the ‘quality’ of a man’s functioning and personal costs he experiences in long-term stress conditions.

scholarly journals Challenges in Quantifying Changes in the Global Water Cycle

2015 ◽  
Vol 96 (7) ◽  
pp. 1097-1115 ◽  
Author(s):  
Gabriele C. Hegerl ◽  
Emily Black ◽  
Richard P. Allan ◽  
William J. Ingram ◽  
Debbie Polson ◽  
...  
Keyword(s):  
Water Cycle ◽  
Internal Variability ◽  
Anthropogenic Aerosols ◽  
Long Term Stability ◽  
Global Water Cycle ◽  
Ocean Salinity ◽  
Long Time ◽  
Global Water

Abstract Understanding observed changes to the global water cycle is key to predicting future climate changes and their impacts. While many datasets document crucial variables such as precipitation, ocean salinity, runoff, and humidity, most are uncertain for determining long-term changes. In situ networks provide long time series over land, but are sparse in many regions, particularly the tropics. Satellite and reanalysis datasets provide global coverage, but their long-term stability is lacking. However, comparisons of changes among related variables can give insights into the robustness of observed changes. For example, ocean salinity, interpreted with an understanding of ocean processes, can help cross-validate precipitation. Observational evidence for human influences on the water cycle is emerging, but uncertainties resulting from internal variability and observational errors are too large to determine whether the observed and simulated changes are consistent. Improvements to the in situ and satellite observing networks that monitor the changing water cycle are required, yet continued data coverage is threatened by funding reductions. Uncertainty both in the role of anthropogenic aerosols and because of the large climate variability presently limits confidence in attribution of observed changes.

Nd-Sr Isotope and REE Evidence for the Long-Term Stability of HLW Glass Products and Trace Metal Migration in a Salt Repository: Corroding Basaltic Dykes in Evaporites as Natural Analogues

1997 ◽  
Vol 506 ◽  
Author(s):  
M. Steinmann ◽  
P. Stille ◽  
K. Mengel ◽  
M. Siemann ◽  
W. Bernotat
Keyword(s):  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Sr Isotope ◽  
Long Term Stability ◽  
Natural Analogues ◽  
Metal Migration ◽  
High Level ◽  
Physical And Chemical ◽  
And Chemical Properties

Basaltic dykes in salt rocks can be used in two different ways as natural analogues for high level radioactive waste (HLW) in a salt repository: In the first approach the basalts serve as analogues for the corrosion behavior of HiLW glass products during millions of years because of many similarities in their physical and chemical properties.

Analysis of corrosion mechanisms of carbon steel in contact with FEBEX bentonite

2019 ◽  
Vol 482 (1) ◽  
pp. 301-312 ◽  
Author(s):  
Masao Uyama ◽  
Takashi Hitomi ◽  
Sayaka Hayagane ◽  
Naoe Kadota ◽  
Hiroyuki Saito ◽  
...  
Keyword(s):  
Accelerated Corrosion ◽  
Geological Disposal ◽  
Barrier Materials ◽  
Long Term Stability ◽  
Realistic Option ◽  
Field Samples ◽  
Engineered Barriers ◽  
Corrosion Mechanisms ◽  
High Level

AbstractGeological disposal is the most realistic option for high-level radioactive waste in Japan. In considering long-term stability for geological disposal, several types of materials have been studied as engineered barriers with a host rock. We focused our study on metal and bentonite as engineered barrier materials and investigated the long-term corrosion tendency of the metal exposed to bentonite. An electrochemical method for inducing accelerated corrosion was studied in a laboratory, and we analysed some field samples from a FEBEX dismantling project (FEBEX-DP) in Switzerland for comparison with our experimental results.

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