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ATOMIC SIMULATIONS OF VOIDS IN U-10wt%Mo FUEL U-10wt%Mo燃料中空洞的原子模拟
Anales AFA Pub Date : 2023-03-28 DOI: 10.31527/analesafa.2023.34.1.17
J.R. Fernández, R.C. Pasianot, M.I. Pascuet
{"title":"ATOMIC SIMULATIONS OF VOIDS IN U-10wt%Mo FUEL","authors":"J.R. Fernández, R.C. Pasianot, M.I. Pascuet","doi":"10.31527/analesafa.2023.34.1.17","DOIUrl":"https://doi.org/10.31527/analesafa.2023.34.1.17","url":null,"abstract":"During neutron irradiation of U-Mo alloys, a phenomenon of fcc ordering of cavities is produced, coherent with the bcc structure of its matrix. In the U-10wt %Mo alloy, the cavities have a diameter of about 30 Å and a superlattice parameter of approximately 120 Å. Many works in the literature implicitly link the overpressurization of the cavities with fission gases (Xe,Kr) as being responsible for the interaction that leads to this ordering. However, recent observations indicate that, in the early burnup stages of the fuel, the cavities that make up this superlattice are practically empty. In this work, we perform molecular dynamics simulations aimed at studying the morphology of an empty cavity (void) and characterizing its mutual interaction with distance and ordering. The cavities are found to be faceted and can only interact at very close distances, of a few atomic planes.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135723335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
FIRST PROTOTYPE OF A LOW-COST VACUUM BAFFLE WITH ELECTRICAL FEEDTHROUGH 第一个带有电馈通的低成本真空挡板的原型
Anales AFA Pub Date : 2023-03-28 DOI: 10.31527/analesafa.2023.34.1.8
J.M. Conde Garrido, M.A. Couselo, J.M. Silveyra
{"title":"FIRST PROTOTYPE OF A LOW-COST VACUUM BAFFLE WITH ELECTRICAL FEEDTHROUGH","authors":"J.M. Conde Garrido, M.A. Couselo, J.M. Silveyra","doi":"10.31527/analesafa.2023.34.1.8","DOIUrl":"https://doi.org/10.31527/analesafa.2023.34.1.8","url":null,"abstract":"n a previous work, Conde Garrido and Silveyra proposed a novel cold trap (baffle) technology capable of trapping contaminants in vacuum systems. The baffle was designed to be applied in systems to synthesize chalcogenide glass thin films by pulsed laser deposition. While traditional baffles are cooled down with compression cooling systems or cooling solutions such as liquid nitrogen, the reported baffle is cooled down by the thermoelectric effect, which allows for reducing the capital investment, operating costs, as well as start-up and maintenance times. This paper presents the construction, tuning, and characterization of the first physical prototype of the baffle. The characterization included, first, the control of the final pressure reached by the device. To characterize the thermal performance of the baffle, a temperature measurement system was designed and manufactured. Within this measurement system, we highlight a low-cost electric vacuum feedthrough. The results indicate that the constructed baffle can reach pressures lower than 2×10−5mbar, while the cold surfaces reach temperatures of approximately−12◦C. The vacuum and cold temperature levels meet the required conditions for the pulsed laser deposition of chalcogenide glass thin films. However, temperatures are not as low as those estimatedfor the virtual prototype (down to−50◦C). Thermal bridges and resistances present in the fabricated device, neglected in the model, were then identified, pointing out opportunities for improvement. Finally, revisions to the current design are proposed that simplify its manufacturing process, improve its robustness and efficiency, and facilitate its operation and maintenance.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135723435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
DEVELOPMENT OF AN FPGA-BASED COINCIDENCE COUNTING SYSTEM FOR MULTIPLE SIGNALS 基于fpga的多信号巧合计数系统的研制
Anales AFA Pub Date : 2023-03-28 DOI: 10.31527/analesafa.2023.34.1.27
M. Bolaños, A. Boette, F. Videla, L. Rebón
{"title":"DEVELOPMENT OF AN FPGA-BASED COINCIDENCE COUNTING SYSTEM FOR MULTIPLE SIGNALS","authors":"M. Bolaños, A. Boette, F. Videla, L. Rebón","doi":"10.31527/analesafa.2023.34.1.27","DOIUrl":"https://doi.org/10.31527/analesafa.2023.34.1.27","url":null,"abstract":"The detection of temporally coincident signals plays an important role in different technological applications for metrology and communication, and particularly, in the area of quantum optics. In this sense, the simultaneous detection of two or more photons allows one to take advantage of the non-classical features of light that manifest themselves in certain types of correlations that cannot be described classically. We present here the development of programmable modules, by using FPGA technology, which are part of the coincident pulse detection and counting system. Our implementation, in a development board from Xilinx, allows to determine when two or more pulses overlap within a temporal window, with a configurable width in the range of 1 and 255 ns to compensate for possible path differences. We obtained the photodetection statistics result of the single and coincident pulse measurements and compared them with that predicted by a theoretical analysis. In addition, we have emulated the signals corresponding to different photon sources through a beam splitter, and obtained the photodetection statistics from which we determine, for each case, the second order correlation function g(2)(τ).","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"91 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135723334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
MASTER CURVE FOR CRYSTALLIZATION OF SB70TE30AMORPHOUS ALLOYS sb70te30非晶合金结晶主曲线
IF 0.3
Anales AFA Pub Date : 2023-03-28 DOI: 10.31527/analesafa.2023.34.1.22
J. Rocca, M. A. Ureña, M. Fontana
{"title":"MASTER CURVE FOR CRYSTALLIZATION OF SB70TE30AMORPHOUS ALLOYS","authors":"J. Rocca, M. A. Ureña, M. Fontana","doi":"10.31527/analesafa.2023.34.1.22","DOIUrl":"https://doi.org/10.31527/analesafa.2023.34.1.22","url":null,"abstract":"One of the possible uses of chalcogenide glasses is their application in phase change memory devices. The operation of these non-volatile memories is based on the use of an alloy with chalcogenide elements as a sensitive material, taking advantage of the great contrast in electrical resistance between the amorphous and crystalline states. The Sb70Te30(atomic percentage) alloy stands out among the chalcogenide materials with these properties. On the other hand, the knowledge of the microscopic mechanisms of the amorphous alloys crystallization allows microstructural control to optimize properties. At this point, differential scanning calorimetry (DSC) has been widely used for the determination of the thermal stability of amorphous alloys. Previously we have started the study of the crystallization kinetics ofSb70Te30amorphous alloys. In this work, a procedure based on the so-called isokinetic hypothesis has been applied to carry out the kinetic analysis of the calorimetric data of continuous heating. In particular, the so-called master curve of the crystallization kinetics of this alloy is determined.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"34 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90617647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
THE EFFECT OF ACQUISITION PARAMETERS IN BRAIN SPECT IMAGING: ASIMIND MONTE CARLO STUDY 采集参数对脑spect成像的影响:基于蒙特卡罗的研究
IF 0.3
Anales AFA Pub Date : 2023-01-15 DOI: 10.31527/analesafa.2022.33.4.99
J. Sanchez, C. Y. Chain, L. H. Illanes
{"title":"THE EFFECT OF ACQUISITION PARAMETERS IN BRAIN SPECT IMAGING: ASIMIND MONTE CARLO STUDY","authors":"J. Sanchez, C. Y. Chain, L. H. Illanes","doi":"10.31527/analesafa.2022.33.4.99","DOIUrl":"https://doi.org/10.31527/analesafa.2022.33.4.99","url":null,"abstract":"In this work cerebral SPECT images were simulated using the SIMIND Monte Carlo code. The specific purpose was the detection of characteristic Alzheimer’s disease (EA) and Major Depression (DM) lesions in simulated brain images, modeling the data acquisition from a source of 99mTc with a gamma camera Picker Prism 2000XP. An anthropomorphic phantom with brain lesions compatible with EA and DM were configured. The operational scenarios were configured on the basis of the frequent parameters recommended by the protocols as well as in working conditions in local health centers. The simulations performed verified that with the setup of the camera gamma, the pathognomonic lesions ofEA and DM can only be visualized if LEHR collimators, patient/detector distance of 16 cm and post-administration waiting time of 45 minutes are used.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"14 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82508196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
FORMATION OF PALLADIUM NANOPARTICLES BY THE POLYOL METHOD:INFLUENCE OF ALKALINE CONDITIONS 多元醇法制备钯纳米颗粒:碱性条件的影响
Anales AFA Pub Date : 2023-01-15 DOI: 10.31527/analesafa.2022.33.4.103
J. F. Sánchez M., H. A. Ritacco, M. D. Sánchez
{"title":"FORMATION OF PALLADIUM NANOPARTICLES BY THE POLYOL METHOD:INFLUENCE OF ALKALINE CONDITIONS","authors":"J. F. Sánchez M., H. A. Ritacco, M. D. Sánchez","doi":"10.31527/analesafa.2022.33.4.103","DOIUrl":"https://doi.org/10.31527/analesafa.2022.33.4.103","url":null,"abstract":"The effect of sodium hydroxide (NaOH) on the size of palladium (Pd) nanoparticles obtained by the simple polyol route was studied. Nanoparticles were synthesized at room temperature using palladium(II) chloride (PdCl2) and NaOH dissolved in ethylene glycol (EG) as reduction reaction promoters. No protective agents or stabilizers were used. We monitored the reaction kinetics and the growth of the nanoparticles by UV-vis spectroscopy and their crystallinity by powder X-ray diffraction (XRD) as a function of NaOH concentration. Crystallite size was evaluated from the diffraction pattern. We found that nanoparticle growth is strongly influenced by the NaOH: Pd molar ratio. Crystallite sizes from 2 to 24 nm were obtained for molar ratios ranging from 1 to 33. At lower concentrations of NaOH, the nucleation and growth process of the nanoparticles were found to be controlled by the reduction of the Pd ion precursors.At higher concentrations, the intermediate reduction of Pd-Cl-OH species determines the nanoparticle growth rate resulting in the formation of the smallest final-size nanoparticles.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135744127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
EMERGENCY EVACUATIONS OF SOCIAL GROUPS 社会群体的紧急疏散
IF 0.3
Anales AFA Pub Date : 2023-01-15 DOI: 10.31527/analesafa.2022.33.4.112
E. Rozan, G. Frank, F. E. Cornes, I. Sticco, C. Dorso
{"title":"EMERGENCY EVACUATIONS OF SOCIAL GROUPS","authors":"E. Rozan, G. Frank, F. E. Cornes, I. Sticco, C. Dorso","doi":"10.31527/analesafa.2022.33.4.112","DOIUrl":"https://doi.org/10.31527/analesafa.2022.33.4.112","url":null,"abstract":"In this work we study how the presence of social groups affects emergency evacuations. This investigation was carried out in the context of the Social Force Model (SFM). We added an attractive force to the SFM, which accounts for the affective feelings that the members of social groups share (colleagues, friends, couples, etc.). We calibrated this force using experimental data, in order to simulate emergency evacuations. We observe that the evacuation time is considerably worsened when attractive feelings are taken into account. Therefore, we conclude that this kind of collective behavior should be included in pedestrian dynamics models.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"10 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90419010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
FOCUS ERROR MEASUREMENT SYSTEM: PRACTICAL DESIGN CONSIDERATIONS 聚焦误差测量系统:实用的设计考虑
IF 0.3
Anales AFA Pub Date : 2023-01-15 DOI: 10.31527/analesafa.2022.33.4.90
F. Zaldivar Escola
{"title":"FOCUS ERROR MEASUREMENT SYSTEM: PRACTICAL DESIGN CONSIDERATIONS","authors":"F. Zaldivar Escola","doi":"10.31527/analesafa.2022.33.4.90","DOIUrl":"https://doi.org/10.31527/analesafa.2022.33.4.90","url":null,"abstract":"A detailed study of the practical design considerations for a focus error measurement system through numerical simulations, based on ABCD ray matrix for Gaussian beams, is presented. The results obtained can be applied in an equivalent way to the cases of reflection or transmission measurement, since these are identical by means of a change of variables. In all cases, the calculations consider the actual shape of the detector used, since these have gaps that separate the quadrants, affecting their efficiency. The distances involved between the optical components are swept in order to study the behavior of the sensitivity, maximizing it depending on the application.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"21 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82417935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
ANALYSIS OF THE EQUIVALENT CURRENTS SYSTEM SQ BEHAVIOUR AT THEARGENTINIAN PERMANENT MAGNETICOBSERVATORIES (ROMP) DURING 2019-2021 2019-2021年阿根廷永磁天文台(romp)等效电流系统sq行为分析
IF 0.3
Anales AFA Pub Date : 2022-10-15 DOI: 10.31527/analesafa.2022.33.3.77
P. A. Sallago
{"title":"ANALYSIS OF THE EQUIVALENT CURRENTS SYSTEM SQ BEHAVIOUR AT THEARGENTINIAN PERMANENT MAGNETICOBSERVATORIES (ROMP) DURING 2019-2021","authors":"P. A. Sallago","doi":"10.31527/analesafa.2022.33.3.77","DOIUrl":"https://doi.org/10.31527/analesafa.2022.33.3.77","url":null,"abstract":"The ionospheric currents that flow in the E layer, the magnetospheric currents and the induced currents in the lithosphere under the station are the sources of geomagnetic variations in the calm days Sq. There exist several methods for estimating the values corresponding to magnetospheric currents. The magnitude of the induced currents contribution is considered about one-third of the measured horizontal variation Sq. In this work, one proceeds to produce the correction for magnetospheric effects by analyzing the ring current index SMR, getting an efficient correction. Subsequently, the values of the north and east components of the surface current densities (KN and KE) above ROMP stations are estimated for calm days with a Kp index less than or equal to 2 in the 2019-2021 interval. It is found that at 14 hs LT, the maximum KN and KE values are recorded at PIL on 12.4.2020, while the minimum KN and KE values are recorded atORC on 10.19.19 and 11.16.20, respectively.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"21 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81597742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
LARGE AMPLITUDE ALFVÉN WAVES IN PARTIALLY IONIZED PLASMAS 部分电离等离子体中的大振幅alfvÉn波
IF 0.3
Anales AFA Pub Date : 2022-10-15 DOI: 10.31527/analesafa.2022.33.3.85
P. A. Sallago
{"title":"LARGE AMPLITUDE ALFVÉN WAVES IN PARTIALLY IONIZED PLASMAS","authors":"P. A. Sallago","doi":"10.31527/analesafa.2022.33.3.85","DOIUrl":"https://doi.org/10.31527/analesafa.2022.33.3.85","url":null,"abstract":"In this paper it is analyzed the propagation of large amplitude Alfvén waves in partially ionized plasmas (PIP) when electronic pressure, Hall and ambipolar terms of Ohm’s law are taken into account. Instead of linearizing and developing the perturbation in monochromatic waves, it is proposed that the perturbation satisfy the Alfvén wave’s conditions. As a result, a solution is found that in the fully ionized limit, it coincides with Sallago and Platzeck solution for Alfvénwaves in Hall magnetohydrodynamics (doi:10.1029/2003JA009920 ). Furthermore, if electronic pressure and Hall terms are null, in the linearized limit, the damping is equal to the one described by De Pontieu, B. Martens, P. C. H. and Hudson, H. S. (DOI = 10.1086/322408), if one imposes that the plasma is a perfect conductor.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"29 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85809510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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