Pub Date : 2021-01-15DOI: 10.31527/ANALESAFA.2020.31.4.157
F. Geser, M. Valente
The mean excitation energy is a fundamental quantity in radiation physics, concerning energy deposition in matter and absorbed dose analytical estimations for charged particles. The stopping of swift ions in different materials strongly depends on this parameter among others. This work intends to fill in part, an empty hole in the theory of stopping power: the need of analitically and theoretically assess the hIi-value for materials. The definition of the mean excitation energy using the dielectric response function is analytically integrable if the inelastic cross section parameters are known. Some dielectric models were studied, aimed at calculating the hIi-value for liquid water by theoretical means, reaching the conclusion that a decay of the order of ω −2 in frequency (energy) is needed as weak condition of the optical energy-loss function for the integrals to converge. Afterwards, the first four discrete excitation levels and the diffuse bands for water are treated in a fully analytical scheme, and further compared with numerical results, providing the contribution of these levels to hIi, with the aim of testing the proposed analytical model.
{"title":"ANALYTICAL PROPOSAL FOR THE ASSESSMENT OF THE MOLECULAR EXCITATION LEVELS TO THE MEAN EXCITATION ENERGY: APPLICATION TO THE WATER MOLECULE","authors":"F. Geser, M. Valente","doi":"10.31527/ANALESAFA.2020.31.4.157","DOIUrl":"https://doi.org/10.31527/ANALESAFA.2020.31.4.157","url":null,"abstract":"The mean excitation energy is a fundamental quantity in radiation physics, concerning energy deposition in matter and absorbed dose analytical estimations for charged particles. The stopping of swift ions in different materials strongly depends on this parameter among others. This work intends to fill in part, an empty hole in the theory of stopping power: the need of analitically and theoretically assess the hIi-value for materials. The definition of the mean excitation energy using the dielectric response function is analytically integrable if the inelastic cross section parameters are known. Some dielectric models were studied, aimed at calculating the hIi-value for liquid water by theoretical means, reaching the conclusion that a decay of the order of ω −2 in frequency (energy) is needed as weak condition of the optical energy-loss function for the integrals to converge. Afterwards, the first four discrete excitation levels and the diffuse bands for water are treated in a fully analytical scheme, and further compared with numerical results, providing the contribution of these levels to hIi, with the aim of testing the proposed analytical model.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90404063","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}
Pub Date : 2021-01-01DOI: 10.31527/analesafa.2021.32.3.83
S. Hernández Guiance, I. D. Coria, I. Irurzun
In this work we perform a theoretical study of dehydrogenation process of CH4 on O2– in both molecular and dissociative states - previously adsorbed on Cr2O3(0001). Calculations are based on Density Functional Theory (DFT). The results show the methanol formation form the adsorption of CH4 on O2 in dissociative state with a formationenergy5:14 eV. Also formaldehyde was formed by the reaction of CH2with molecular O2(Eads=6:09 eV) and dioxymethylene by the reaction of CH2with O2 previously adsorbed in dissociative state on Cr2O3(0001), withEads=8:17 eV. Finally, the vibrational modes found by DFT for each of the species were compared, which are in good agreement with those of reference bibliography. This allows us to support the values found both by technical calculations and by experimental methods.
{"title":"ENERGIES AND VIBRATIONAL MODES OF SPECIES FORMED BY DEHYDROGENATION OF CH4 IN PRESENCE OF O2 OVER Cr2O3(0001)","authors":"S. Hernández Guiance, I. D. Coria, I. Irurzun","doi":"10.31527/analesafa.2021.32.3.83","DOIUrl":"https://doi.org/10.31527/analesafa.2021.32.3.83","url":null,"abstract":"In this work we perform a theoretical study of dehydrogenation process of CH4 on O2– in both molecular and dissociative states - previously adsorbed on Cr2O3(0001). Calculations are based on Density Functional Theory (DFT). The results show the methanol formation form the adsorption of CH4 on O2 in dissociative state with a formationenergy5:14 eV. Also formaldehyde was formed by the reaction of CH2with molecular O2(Eads=6:09 eV) and dioxymethylene by the reaction of CH2with O2 previously adsorbed in dissociative state on Cr2O3(0001), withEads=8:17 eV. Finally, the vibrational modes found by DFT for each of the species were compared, which are in good agreement with those of reference bibliography. This allows us to support the values found both by technical calculations and by experimental methods.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"6 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79655994","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}
Pub Date : 2021-01-01DOI: 10.31527/analesafa.2021.32.3.72
Natalí Guisande, J. Sanchez, L. Garavaglia, S. Rozanskas, G. Dopta, K. Pertusi, V. Sanz, A. Mele, L. Illanes, C. Y. Chain
This work analyzes the reliability of the radiochemical purity control method of99mTc-MIBI used in nuclear medicine services and the influence of the greater presence of radiochemical impurities in the diagnostic quality of the obtained images.
{"title":"EFFECT OF THE RADIOCHEMICAL IMPURITIES OF99mTC-MIBI ON THEDIAGNOSTIC QUALITY OF THE IMAGES IN NUCLEAR MEDICINE","authors":"Natalí Guisande, J. Sanchez, L. Garavaglia, S. Rozanskas, G. Dopta, K. Pertusi, V. Sanz, A. Mele, L. Illanes, C. Y. Chain","doi":"10.31527/analesafa.2021.32.3.72","DOIUrl":"https://doi.org/10.31527/analesafa.2021.32.3.72","url":null,"abstract":"This work analyzes the reliability of the radiochemical purity control method of99mTc-MIBI used in nuclear medicine services and the influence of the greater presence of radiochemical impurities in the diagnostic quality of the obtained images.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"4 4 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91188264","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}
Pub Date : 2021-01-01DOI: 10.31527/analesafa.2021.32.3.62
N. Correa, A. Naudi, E. Diliscia, M. C. Pérez, S. Laugero, A. Hiraldo, E. Bonfils, J. Adur
n this article we present the results of the design, development and characterization of an extremely low-frequency electromagnetic fields generator to carry out experiments with small animals. For the design of the exposure system, we took into account that its configuration should allow the application of an electromagnetic field that meets uniformity and field intensity criteria, while making it possible to observe, manipulate and locate the sample easily, a fact that imposes accessibility requirements. For the application of different electromagnetic fields exposure protocols in the future, the generator must allow calibrated and homogeneous emissions, under known exposure conditions. Results of the constructive process are presented, in which the proposed materials and methods are analyzed, as well as the system performance results.
{"title":"DESIGN, DEVELOPMENT AND CHARACTERIZATION OF AN EXTREMELY LOWFREQUENCY ELECTROMAGNETIC FIELDS GENERATOR","authors":"N. Correa, A. Naudi, E. Diliscia, M. C. Pérez, S. Laugero, A. Hiraldo, E. Bonfils, J. Adur","doi":"10.31527/analesafa.2021.32.3.62","DOIUrl":"https://doi.org/10.31527/analesafa.2021.32.3.62","url":null,"abstract":"n this article we present the results of the design, development and characterization of an extremely low-frequency electromagnetic fields generator to carry out experiments with small animals. For the design of the exposure system, we took into account that its configuration should allow the application of an electromagnetic field that meets uniformity and field intensity criteria, while making it possible to observe, manipulate and locate the sample easily, a fact that imposes accessibility requirements. For the application of different electromagnetic fields exposure protocols in the future, the generator must allow calibrated and homogeneous emissions, under known exposure conditions. Results of the constructive process are presented, in which the proposed materials and methods are analyzed, as well as the system performance results.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"38 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85810490","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}
Pub Date : 2021-01-01DOI: 10.31527/analesafa.2021.32.3.76
P. Perillo, D. Rodriguez
In this paper, a humidity sensor based on CuO has been successfully fabricated. Thin-film of CuO nanorices were synthesized by Successive Ionic Layer Adsorption and Reaction (SILAR) method on silicon wafer with Si3N4thinlayer as a substrate. The microstructure and morphology of the samples were investigated using X-ray diffraction(XRD) and scanning electron microscopy (SEM). Humidity sensing properties of the thin films have been studied. The sensing response has been measured in the relative humidity (RH) range from 20 up to 80 % at room temperature. It was found that impedance of the system decreases as the RH was increased. The prepared sensor revealed good reversibility with response and recovery time of 130 s and 320 s respectively. The complex impedance spectra were analyzed in the range of 0.1 to 1 kHz. This type of humidity sensor can be used as a new generation of ecological sensors with low cost and good stability. It makes the sensor a candidate for practical applications.
{"title":"HUMIDITY SENSOR USING CuO NANORICES THIN FILM","authors":"P. Perillo, D. Rodriguez","doi":"10.31527/analesafa.2021.32.3.76","DOIUrl":"https://doi.org/10.31527/analesafa.2021.32.3.76","url":null,"abstract":"In this paper, a humidity sensor based on CuO has been successfully fabricated. Thin-film of CuO nanorices were synthesized by Successive Ionic Layer Adsorption and Reaction (SILAR) method on silicon wafer with Si3N4thinlayer as a substrate. The microstructure and morphology of the samples were investigated using X-ray diffraction(XRD) and scanning electron microscopy (SEM). Humidity sensing properties of the thin films have been studied. The sensing response has been measured in the relative humidity (RH) range from 20 up to 80 % at room temperature. It was found that impedance of the system decreases as the RH was increased. The prepared sensor revealed good reversibility with response and recovery time of 130 s and 320 s respectively. The complex impedance spectra were analyzed in the range of 0.1 to 1 kHz. This type of humidity sensor can be used as a new generation of ecological sensors with low cost and good stability. It makes the sensor a candidate for practical applications.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"134 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85291189","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}
Pub Date : 2020-09-14DOI: 10.31527/analesafa.2019.30.4.72
Alejandro Gangui
This paper offers a synthesis of the positions in the literature regarding controversies about the multiverse. After re-viewing some simple elements of modern cosmology and its observational limitations, we will present the history ofthe ideas that led, first, to the proposal of the anthropic principle and, years later, to the possible existence of causallydisconnected domains, eventually endowed with their own laws and fundamental constants, not all compatible with theexistence of observers, which were globally baptized with the confusing name of parallel universes or multiverse.
{"title":"THE MULTIVERSE CONTROVERSY","authors":"Alejandro Gangui","doi":"10.31527/analesafa.2019.30.4.72","DOIUrl":"https://doi.org/10.31527/analesafa.2019.30.4.72","url":null,"abstract":"This paper offers a synthesis of the positions in the literature regarding controversies about the multiverse. After re-viewing some simple elements of modern cosmology and its observational limitations, we will present the history ofthe ideas that led, first, to the proposal of the anthropic principle and, years later, to the possible existence of causallydisconnected domains, eventually endowed with their own laws and fundamental constants, not all compatible with theexistence of observers, which were globally baptized with the confusing name of parallel universes or multiverse.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"9 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2020-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76162016","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}
Pub Date : 2020-02-25DOI: 10.31527/analesafa.2020.31.1.29
P. Poggi
Limitations to the speed of evolution of quantum systems, typically referred to as quantum speed limits (QSLs), have important consequences for quantum control problems. However, in its standard formulation, is not straightforward to obtain meaningful QSL bounds for time-dependent Hamiltonians with unknown control parameters. In this paper we present a short introductory overview of quantum speed limit for unitary dynamics and its connection to quantum control. We then analyze potential methods for obtaining new bounds on control times inspired by the QSL. We finally extend the work in [Poggi, Lombardo and WisniackiEPL104 40005 (2013)] by studying the properties and limitations of these new bounds in the context of a driven two-level quantum system.
{"title":"ANALYSIS OF LOWER BOUNDS FOR QUANTUM CONTROL TIMES AND THEIR RELATION TO THE QUANTUM SPEED LIMIT","authors":"P. Poggi","doi":"10.31527/analesafa.2020.31.1.29","DOIUrl":"https://doi.org/10.31527/analesafa.2020.31.1.29","url":null,"abstract":"Limitations to the speed of evolution of quantum systems, typically referred to as quantum speed limits (QSLs), have important consequences for quantum control problems. However, in its standard formulation, is not straightforward to obtain meaningful QSL bounds for time-dependent Hamiltonians with unknown control parameters. In this paper we present a short introductory overview of quantum speed limit for unitary dynamics and its connection to quantum control. We then analyze potential methods for obtaining new bounds on control times inspired by the QSL. We finally extend the work in [Poggi, Lombardo and WisniackiEPL104 40005 (2013)] by studying the properties and limitations of these new bounds in the context of a driven two-level quantum system.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2020-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74487292","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}
Pub Date : 2020-01-01DOI: 10.31527/analesafa.2020.31.3.86
G. Varela, Córdoba Argentina. Famaf Ciudad Universitaria, D. Flores, P. I. Achával, C. L. D. Prinzio
The surface of a monocrystalline ice sample was observed at −5 ◦C (268 K). For which it was superficially polished and allowed to evolve in the presence of activated silica gel for three hours. The evolution of a depression was studied using three-dimensional micrographs obtained with an Olympus OLS4000 LEXT confocal microscope. A predominance of surface diffusion transport was found in the evolution of the depression. This is based both on the value obtained for the surface diffusion coefficient, as well as on the values found for the exponents corresponding to the evolution of the depth of the well and its width.
{"title":"FLATTENING OF A SCRATCH ON SINGLE CRYSTAL ICE SURFACE","authors":"G. Varela, Córdoba Argentina. Famaf Ciudad Universitaria, D. Flores, P. I. Achával, C. L. D. Prinzio","doi":"10.31527/analesafa.2020.31.3.86","DOIUrl":"https://doi.org/10.31527/analesafa.2020.31.3.86","url":null,"abstract":"The surface of a monocrystalline ice sample was observed at −5 ◦C (268 K). For which it was superficially polished and allowed to evolve in the presence of activated silica gel for three hours. The evolution of a depression was studied using three-dimensional micrographs obtained with an Olympus OLS4000 LEXT confocal microscope. A predominance of surface diffusion transport was found in the evolution of the depression. This is based both on the value obtained for the surface diffusion coefficient, as well as on the values found for the exponents corresponding to the evolution of the depth of the well and its width.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"98 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76128800","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}
Pub Date : 2020-01-01DOI: 10.31527/analesafa.2020.31.3.107
J. M. Intyre, J. Gomba, C. A. Perazzo, Pinto Tandil Argentina. Cificen
We study the migration of droplets on a solid surface which is under a uniform temperature gradient. The present article focus on partial wetting fluids which surface tension depends on the squared temperature. These type of liquids, called self-rewetting, show a complex dynamics and here we will compare with those liquids of linear dependence in the temperature. Unlike to the latter ones, the droplet width increases with the time.
{"title":"DRIVEN DROPLETS BY THERMOCAPILLARY EFFECT: QUADRATIC DEPENDENCE OF THE SURFACE TENSION ON THE TEMPERATURE","authors":"J. M. Intyre, J. Gomba, C. A. Perazzo, Pinto Tandil Argentina. Cificen","doi":"10.31527/analesafa.2020.31.3.107","DOIUrl":"https://doi.org/10.31527/analesafa.2020.31.3.107","url":null,"abstract":"We study the migration of droplets on a solid surface which is under a uniform temperature gradient. The present article focus on partial wetting fluids which surface tension depends on the squared temperature. These type of liquids, called self-rewetting, show a complex dynamics and here we will compare with those liquids of linear dependence in the temperature. Unlike to the latter ones, the droplet width increases with the time.","PeriodicalId":41478,"journal":{"name":"Anales AFA","volume":"17 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88873829","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}
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