Pub Date : 2022-06-02DOI: 10.26565/2312-4334-2022-2-17
V. Trusova, O. Zhytniakivska, U. Tarabara, Kateryna Vus, G. Gorbenko
During the last decades growing attention has been paid to ascertaining the factors responsible for the toxic potential of particular protein aggregates, amyloid fibrils, whose formation is associated with a range of human pathologies, including the neurodegenerative diseases, systemic amyloidosis, type II diabetes, etc. Despite significant progress in elucidating the mechanisms of cytotoxic action of amyloid fibrils, the role of fibril-protein interactions in determining the amyloid toxicity remains poorly understood. In view of this, in the present study the molecular docking techniques has been employed to investigate the interactions between the insulin amyloid fibrils (InsF) and three biologically important multifunctional proteins, viz. serum albumin, lysozyme and insulin in their native globular state. Using the ClusPro, HDOCK, PatchDock and COCOMAPS web servers, along with BIOVIA Discovery Studio software, the structural characteristics of fibril-protein complexes such as the number of interacting amino acid residues, the amount of residues at fibril and protein interfaces, the contributions of various kinds of interactions, buried area upon the complex formation, etc. It was found that i) hydrophilic-hydrophilic and hydrophilic-hydrophobic interactions play dominating role in the formation of fibril-protein complexes; ii) there is no significant differences between the investigated proteins in the number of fibrillar interacting residues; iii) the dominating hydrogen bond forming residues are represented by glutamine and asparagine in fibrillar insulin, lysine in serum albumin and arginine in lysozyme; iv) polar buried area exceeds the nonpolar one upon the protein complexation with the insulin fibrils. The molecular docking evidence for the localization of phosphonium fluorescent dye TDV at the fibril-protein interface was obtained.
{"title":"Interactions of Fibrillar Insulin with Proteins: A Molecular Docking Study","authors":"V. Trusova, O. Zhytniakivska, U. Tarabara, Kateryna Vus, G. Gorbenko","doi":"10.26565/2312-4334-2022-2-17","DOIUrl":"https://doi.org/10.26565/2312-4334-2022-2-17","url":null,"abstract":"During the last decades growing attention has been paid to ascertaining the factors responsible for the toxic potential of particular protein aggregates, amyloid fibrils, whose formation is associated with a range of human pathologies, including the neurodegenerative diseases, systemic amyloidosis, type II diabetes, etc. Despite significant progress in elucidating the mechanisms of cytotoxic action of amyloid fibrils, the role of fibril-protein interactions in determining the amyloid toxicity remains poorly understood. In view of this, in the present study the molecular docking techniques has been employed to investigate the interactions between the insulin amyloid fibrils (InsF) and three biologically important multifunctional proteins, viz. serum albumin, lysozyme and insulin in their native globular state. Using the ClusPro, HDOCK, PatchDock and COCOMAPS web servers, along with BIOVIA Discovery Studio software, the structural characteristics of fibril-protein complexes such as the number of interacting amino acid residues, the amount of residues at fibril and protein interfaces, the contributions of various kinds of interactions, buried area upon the complex formation, etc. It was found that i) hydrophilic-hydrophilic and hydrophilic-hydrophobic interactions play dominating role in the formation of fibril-protein complexes; ii) there is no significant differences between the investigated proteins in the number of fibrillar interacting residues; iii) the dominating hydrogen bond forming residues are represented by glutamine and asparagine in fibrillar insulin, lysine in serum albumin and arginine in lysozyme; iv) polar buried area exceeds the nonpolar one upon the protein complexation with the insulin fibrils. The molecular docking evidence for the localization of phosphonium fluorescent dye TDV at the fibril-protein interface was obtained.","PeriodicalId":78400,"journal":{"name":"La Ricerca scientifica. 2. ser., pt. 2: Rendiconti. Sezione B: Biologica","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80483893","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 : 2022-06-02DOI: 10.26565/2312-4334-2022-2-01
A. Kalinichenko, V. Strel’nitskij
Within the framework of the model of the nonlocal thermoelastic peak of low-energy ion, the formation of intrinsic stress in a carbon coating deposited from the vacuum arc plasma in the argon atmosphere is theoretically studied. It is shown that the flow of particles bombarding the deposited coating contains, along with C+ ions, also Ar+ ions involved in the formation of intrinsic stress in the coating. The flux density of Ar+ ions resulting from ionization losses of C+ ions passing through the argon atmosphere is proportional to both the flux density of C+ ions and the density (pressure) of argon. Expressions are obtained for the intrinsic stress in the deposited carbon coating depending on the bias potential on the substrate and the argon pressure for the cases of both constant and pulsed potentials. The analysis of the obtained expressions shows that the intrinsic stress in the carbon coating decrease with increasing argon pressure.
{"title":"Influence of the Inert Gas Pressure on Intrinsic Stress in Diamond-Like Coating Deposited From Vacuum Arc Carbon Plasma","authors":"A. Kalinichenko, V. Strel’nitskij","doi":"10.26565/2312-4334-2022-2-01","DOIUrl":"https://doi.org/10.26565/2312-4334-2022-2-01","url":null,"abstract":"Within the framework of the model of the nonlocal thermoelastic peak of low-energy ion, the formation of intrinsic stress in a carbon coating deposited from the vacuum arc plasma in the argon atmosphere is theoretically studied. It is shown that the flow of particles bombarding the deposited coating contains, along with C+ ions, also Ar+ ions involved in the formation of intrinsic stress in the coating. The flux density of Ar+ ions resulting from ionization losses of C+ ions passing through the argon atmosphere is proportional to both the flux density of C+ ions and the density (pressure) of argon. Expressions are obtained for the intrinsic stress in the deposited carbon coating depending on the bias potential on the substrate and the argon pressure for the cases of both constant and pulsed potentials. The analysis of the obtained expressions shows that the intrinsic stress in the carbon coating decrease with increasing argon pressure.","PeriodicalId":78400,"journal":{"name":"La Ricerca scientifica. 2. ser., pt. 2: Rendiconti. Sezione B: Biologica","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78346567","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 : 2022-06-02DOI: 10.26565/2312-4334-2022-2-07
M. A. Shafi, M. Khan, Sumayya Bibi, Muhammad Yasir Shafi, Noreena Rabbani, H. Ullah, Laiq Khan, B. Marí
In this research work, the electrical simulation of 1D5P model solar cell is done using LTSpice-IV simulation software. In this work effect of environmental conditions i.e temperature, solar irradiance, and parasitic parameters i.e series as well as shunt resistances was carried out. It has been discovered that as temperature increases the performance of solar cell decrease because temperature causes to increase the recombination phenomenon and hence lower the performance. However, when the temperature rises from 00C to 500C, the I-V and P-V curves move to the origin showing the negative effect of increasing temperature on the solar cell. Solar irradiance has major role on the performance of solar cell. As solar irradiance increases from 250 Wm-2 to 1000 Wm-2, the performance of solar cell increases accordingly and I-V as well as P-V curve moves away from the origin. It is concluded that for different series resistances, I-V along with P-V characteristic of 1D5P model solar cell varies, as at 0.02Ω series resistance, a maximum short circuit current and maximum power is obtained. But when series resistance increased up 2 ohm only, the I-V and P-V curves moves to origin drastically. Shunt Resistance is the path of reverse current of the cell. As the shunt resistance increases, the path for reverse current decreased, hence all current goes to load, hence maximum power is obtained. Similarly when the value of shunt resistance decreased, the voltage-controlled section of I-V characteristics curve is moved closer to the origin hence reduced the solar cell performance. It's critical to understand how different factors affect the I-V and P-V characteristics curves of solar cells. The open circuit voltage, short circuit current and maximum power is all variable. The influence of these factors may be extremely beneficial when tracking highest power point of a solar cell applying various methods.
{"title":"Effect of Parasitic Parameters and Environmental Conditions on I-V and P-V Characteristics of 1D5P Model Solar PV Cell Using LTSPICE-IV","authors":"M. A. Shafi, M. Khan, Sumayya Bibi, Muhammad Yasir Shafi, Noreena Rabbani, H. Ullah, Laiq Khan, B. Marí","doi":"10.26565/2312-4334-2022-2-07","DOIUrl":"https://doi.org/10.26565/2312-4334-2022-2-07","url":null,"abstract":"In this research work, the electrical simulation of 1D5P model solar cell is done using LTSpice-IV simulation software. In this work effect of environmental conditions i.e temperature, solar irradiance, and parasitic parameters i.e series as well as shunt resistances was carried out. It has been discovered that as temperature increases the performance of solar cell decrease because temperature causes to increase the recombination phenomenon and hence lower the performance. However, when the temperature rises from 00C to 500C, the I-V and P-V curves move to the origin showing the negative effect of increasing temperature on the solar cell. Solar irradiance has major role on the performance of solar cell. As solar irradiance increases from 250 Wm-2 to 1000 Wm-2, the performance of solar cell increases accordingly and I-V as well as P-V curve moves away from the origin. It is concluded that for different series resistances, I-V along with P-V characteristic of 1D5P model solar cell varies, as at 0.02Ω series resistance, a maximum short circuit current and maximum power is obtained. But when series resistance increased up 2 ohm only, the I-V and P-V curves moves to origin drastically. Shunt Resistance is the path of reverse current of the cell. As the shunt resistance increases, the path for reverse current decreased, hence all current goes to load, hence maximum power is obtained. Similarly when the value of shunt resistance decreased, the voltage-controlled section of I-V characteristics curve is moved closer to the origin hence reduced the solar cell performance. It's critical to understand how different factors affect the I-V and P-V characteristics curves of solar cells. The open circuit voltage, short circuit current and maximum power is all variable. The influence of these factors may be extremely beneficial when tracking highest power point of a solar cell applying various methods.","PeriodicalId":78400,"journal":{"name":"La Ricerca scientifica. 2. ser., pt. 2: Rendiconti. Sezione B: Biologica","volume":"48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75373613","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 : 2022-06-02DOI: 10.26565/2312-4334-2022-2-02
E. Inyang, P. C. Iwuji, J. Ntibi, Eddy S. William, E. Ibanga
In this study, the Schrödinger equation with the Hulthén plus screened Kratzer potentials (HSKP) are solved via the Nikiforov-Uvarov (NU) and the series expansion methods. We obtained the energy equation and the wave function in closed form with Greene-Aldrich approximation via the NU method. The series expansion method was also used to obtain the energy equation of HSKP. Three distinct cases were obtained from the combined potentials. The energy eigenvalues of HSKP for HCl, LiH, H2, and NO diatomic molecules were computed for various quantum states. To test the accuracy of our results, we computed the bound states energy of HCl and LiH, for a special case of Kratzer and screened Kratzer potentials, which are in excellent agreement with the report of other researchers.
{"title":"Solutions of the Schrödinger equation with Hulthén-screened Kratzer potential: Application to Diatomic Molecules","authors":"E. Inyang, P. C. Iwuji, J. Ntibi, Eddy S. William, E. Ibanga","doi":"10.26565/2312-4334-2022-2-02","DOIUrl":"https://doi.org/10.26565/2312-4334-2022-2-02","url":null,"abstract":"In this study, the Schrödinger equation with the Hulthén plus screened Kratzer potentials (HSKP) are solved via the Nikiforov-Uvarov (NU) and the series expansion methods. We obtained the energy equation and the wave function in closed form with Greene-Aldrich approximation via the NU method. The series expansion method was also used to obtain the energy equation of HSKP. Three distinct cases were obtained from the combined potentials. The energy eigenvalues of HSKP for HCl, LiH, H2, and NO diatomic molecules were computed for various quantum states. To test the accuracy of our results, we computed the bound states energy of HCl and LiH, for a special case of Kratzer and screened Kratzer potentials, which are in excellent agreement with the report of other researchers.","PeriodicalId":78400,"journal":{"name":"La Ricerca scientifica. 2. ser., pt. 2: Rendiconti. Sezione B: Biologica","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83143367","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 : 2022-06-02DOI: 10.26565/2312-4334-2022-2-04
Viktoriia Yu. Аksenova, I. Marchenko, I. Marchenko
This paper is devoted to the studies of the specific features of the simulation of the particle diffusion processes in space – periodic potentials using Langevin equations. Different methods used for the presetting of initial conditions and their effect on the obtained solutions have been analyzed. It is shown that the system is nonequilibrium for all the methods of the presetting of initial conditions during a certain time interval of ttrm. This interval is increased as 1/γ with a decrease in the friction coefficient. A reasonable description of the transient processes of particle transport and diffusion requires a preliminary system thermalization procedure. A new method of the presetting of initial conditions that provides the most accurate description of equilibrium system has been suggested. It consists in the generation of the initial particle coordinates and velocities that correspond to the equilibrium distribution of harmonic oscillators with a specified temperature. The use of such initial conditions enables the computations with a good accuracy using no thermalization procedure at T < 0.1. The classic method of the determination of diffusion coefficients D as a limit limt→ꝏ (σ2/t) has been analyzed. It was shown that the use of it for computer-aided calculations is limited by the restricted computational time. It results in that the computation of D under certain conditions becomes impossible. A new method was suggested for the determination of the diffusion coefficient using the linear approximation of the dependence of dispersion on time. This approximation can only be possible after the kinetic temperature attains its stationary value. The suggested method requires several orders of magnitude less time in comparison to the classic method. As a result, it enables the computation of the diffusion coefficient even in the cases of total previous failure. The obtained data are of great importance for correct simulation computations of diffusion processes and for the appropriate physical interpretations of obtained data.
{"title":"Specific Features of the Simulation of the Particle Diffusion Processes in Spatially Periodic Fields","authors":"Viktoriia Yu. Аksenova, I. Marchenko, I. Marchenko","doi":"10.26565/2312-4334-2022-2-04","DOIUrl":"https://doi.org/10.26565/2312-4334-2022-2-04","url":null,"abstract":"This paper is devoted to the studies of the specific features of the simulation of the particle diffusion processes in space – periodic potentials using Langevin equations. Different methods used for the presetting of initial conditions and their effect on the obtained solutions have been analyzed. It is shown that the system is nonequilibrium for all the methods of the presetting of initial conditions during a certain time interval of ttrm. This interval is increased as 1/γ with a decrease in the friction coefficient. A reasonable description of the transient processes of particle transport and diffusion requires a preliminary system thermalization procedure. A new method of the presetting of initial conditions that provides the most accurate description of equilibrium system has been suggested. It consists in the generation of the initial particle coordinates and velocities that correspond to the equilibrium distribution of harmonic oscillators with a specified temperature. The use of such initial conditions enables the computations with a good accuracy using no thermalization procedure at T < 0.1. The classic method of the determination of diffusion coefficients D as a limit limt→ꝏ (σ2/t) has been analyzed. It was shown that the use of it for computer-aided calculations is limited by the restricted computational time. It results in that the computation of D under certain conditions becomes impossible. A new method was suggested for the determination of the diffusion coefficient using the linear approximation of the dependence of dispersion on time. This approximation can only be possible after the kinetic temperature attains its stationary value. The suggested method requires several orders of magnitude less time in comparison to the classic method. As a result, it enables the computation of the diffusion coefficient even in the cases of total previous failure. The obtained data are of great importance for correct simulation computations of diffusion processes and for the appropriate physical interpretations of obtained data.","PeriodicalId":78400,"journal":{"name":"La Ricerca scientifica. 2. ser., pt. 2: Rendiconti. Sezione B: Biologica","volume":"103 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80733170","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 : 2022-06-02DOI: 10.26565/2312-4334-2022-2-19
Waleed S. Hwash
The current study is about the structure of 17B, which has been investigated by the Microscopic Cluster Model. The binding energy and neutron position of two valence neutrons of Beta-decay and neutron emission have been calculated. A cluster configuration of the Halo nucleus inspired me to consider all radioisotopes have cluster configuration before the decay process. The Jacobi coordinates has been used to investigated the 17B nucleus. The Jacobi coordinate is a very well technique to describe such as a three-body system or halo structure. The 17B has Borromean property, so it has been defined in T-configuration in this coordinates. The angle in the figure defines an angle of halo neutron motion around the core. The study has considered a deformation of the core as a high influence on the binding of the valence neutrons.
{"title":"Solutions of the Schrödinger Equation with Hul Neutron Position for Beta (β-) Decay and Neutron Emission","authors":"Waleed S. Hwash","doi":"10.26565/2312-4334-2022-2-19","DOIUrl":"https://doi.org/10.26565/2312-4334-2022-2-19","url":null,"abstract":"The current study is about the structure of 17B, which has been investigated by the Microscopic Cluster Model. The binding energy and neutron position of two valence neutrons of Beta-decay and neutron emission have been calculated. A cluster configuration of the Halo nucleus inspired me to consider all radioisotopes have cluster configuration before the decay process. The Jacobi coordinates has been used to investigated the 17B nucleus. The Jacobi coordinate is a very well technique to describe such as a three-body system or halo structure. The 17B has Borromean property, so it has been defined in T-configuration in this coordinates. The angle in the figure defines an angle of halo neutron motion around the core. The study has considered a deformation of the core as a high influence on the binding of the valence neutrons.","PeriodicalId":78400,"journal":{"name":"La Ricerca scientifica. 2. ser., pt. 2: Rendiconti. Sezione B: Biologica","volume":"144 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80343385","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 : 2022-06-02DOI: 10.26565/2312-4334-2022-2-15
V. Morgunov, Imre Madar, S. Lytovchenko, V. Chyshkala, B. Mazilin
The article provides a description of steps which were made to make comparison between numerically simulated and measured dose rates in Izotop gamma-irradiation facility (Budapest, Hungary) Numerical simulation was carried out with the help of software toolkit GEANT4. Dose measurement were made by ethanol-chlorobenzene (ECB) dosimeters. The comparison shows a good agreement between simulated and measured values. Worst accuracy was 17.08%.
{"title":"Comparison of Numerically Simulated and Measured Dose Rates for Gamma-Irradiation Facility","authors":"V. Morgunov, Imre Madar, S. Lytovchenko, V. Chyshkala, B. Mazilin","doi":"10.26565/2312-4334-2022-2-15","DOIUrl":"https://doi.org/10.26565/2312-4334-2022-2-15","url":null,"abstract":"The article provides a description of steps which were made to make comparison between numerically simulated and measured dose rates in Izotop gamma-irradiation facility (Budapest, Hungary) Numerical simulation was carried out with the help of software toolkit GEANT4. Dose measurement were made by ethanol-chlorobenzene (ECB) dosimeters. The comparison shows a good agreement between simulated and measured values. Worst accuracy was 17.08%.","PeriodicalId":78400,"journal":{"name":"La Ricerca scientifica. 2. ser., pt. 2: Rendiconti. Sezione B: Biologica","volume":"211 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77160720","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 : 2022-06-02DOI: 10.26565/2312-4334-2022-2-11
Junjie Chen
The increasing popularity of carbon nanotubes has created a demand for greater scientific understanding of the characteristics of thermal transport in nanostructured materials. However, the effects of impurities, misalignments, and structure factors on the thermal conductivity of carbon nanotube films and fibers are still poorly understood. Carbon nanotube films and fibers were produced, and the parallel thermal conductance technique was employed to determine the thermal conductivity. The effects of carbon nanotube structure, purity, and alignment on the thermal conductivity of carbon films and fibers were investigated to understand the characteristics of thermal transport in the nanostructured material. The importance of bulk density and cross-sectional area was determined experimentally. The results indicated that the prepared carbon nanotube films and fibers are very efficient at conducting heat. The structure, purity, and alignment of carbon nanotubes play a fundamentally important role in determining the heat conduction properties of carbon films and fibers. Single-walled carbon nanotube films and fibers generally have high thermal conductivity. The presence of non-carbonaceous impurities degrades the thermal performance due to the low degree of bundle contact. The thermal conductivity may present power law dependence with temperature. The specific thermal conductivity decreases with increasing bulk density. At room temperature, a maximum specific thermal conductivity is obtained but Umklapp scattering occurs. The specific thermal conductivity of carbon nanotube fibers is significantly higher than that of carbon nanotube films due to the increased degree of bundle alignment.
{"title":"Effects of Different Factors on the Heat Conduction Properties of Carbon Films and Fibers","authors":"Junjie Chen","doi":"10.26565/2312-4334-2022-2-11","DOIUrl":"https://doi.org/10.26565/2312-4334-2022-2-11","url":null,"abstract":"The increasing popularity of carbon nanotubes has created a demand for greater scientific understanding of the characteristics of thermal transport in nanostructured materials. However, the effects of impurities, misalignments, and structure factors on the thermal conductivity of carbon nanotube films and fibers are still poorly understood. Carbon nanotube films and fibers were produced, and the parallel thermal conductance technique was employed to determine the thermal conductivity. The effects of carbon nanotube structure, purity, and alignment on the thermal conductivity of carbon films and fibers were investigated to understand the characteristics of thermal transport in the nanostructured material. The importance of bulk density and cross-sectional area was determined experimentally. The results indicated that the prepared carbon nanotube films and fibers are very efficient at conducting heat. The structure, purity, and alignment of carbon nanotubes play a fundamentally important role in determining the heat conduction properties of carbon films and fibers. Single-walled carbon nanotube films and fibers generally have high thermal conductivity. The presence of non-carbonaceous impurities degrades the thermal performance due to the low degree of bundle contact. The thermal conductivity may present power law dependence with temperature. The specific thermal conductivity decreases with increasing bulk density. At room temperature, a maximum specific thermal conductivity is obtained but Umklapp scattering occurs. The specific thermal conductivity of carbon nanotube fibers is significantly higher than that of carbon nanotube films due to the increased degree of bundle alignment.","PeriodicalId":78400,"journal":{"name":"La Ricerca scientifica. 2. ser., pt. 2: Rendiconti. Sezione B: Biologica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88638536","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 : 2022-06-02DOI: 10.26565/2312-4334-2022-2-13
Mahmoud Al-Elaimi
This article presents the theoretical evaluation of the structural, mechanical, thermal and electrical properties of half-Heusler (ZrCo1-xNixBi = 0, 0.25, 0.75 and 1) alloys in the framework of density functional theory (DFT) that is implemented in WIEN2k code. Equilibrium lattice parameters are found agree with previous literature. Several calculated mechanical properties are revealed that all studied alloys are mechanically stable. According to the critical values for B/G, Ni-doped ZrCoBi alloys are ductile, whereas ZrCoBi and ZrNiBi are brittle. The band structure and density of states of the present compounds show that ZrCoBi has a semiconducting nature, while Ni-doped ZrCoBi has a half-metallic nature. The structural reforms, brought to ZrCoBi as the Ni-dopant concentration increases at the site of Co-atom, showed an increase in its metallicity, conductivity and ductility, and a decrease in its rigidity, stiffness, minimum thermal conductivity, melting and Debye temperatures. According to the results obtained, ( ZrCo1-xNixBi = 0, 0.25, 0.75 and 1) alloys could have potential thermal and electronic applications.
{"title":"Structural, Thermal, and Electronic Investigation of ZrCo1-xNixBi (x=0, 0.25, 0.75, and 1) Half-Heusler Alloys","authors":"Mahmoud Al-Elaimi","doi":"10.26565/2312-4334-2022-2-13","DOIUrl":"https://doi.org/10.26565/2312-4334-2022-2-13","url":null,"abstract":"This article presents the theoretical evaluation of the structural, mechanical, thermal and electrical properties of half-Heusler (ZrCo1-xNixBi = 0, 0.25, 0.75 and 1) alloys in the framework of density functional theory (DFT) that is implemented in WIEN2k code. Equilibrium lattice parameters are found agree with previous literature. Several calculated mechanical properties are revealed that all studied alloys are mechanically stable. According to the critical values for B/G, Ni-doped ZrCoBi alloys are ductile, whereas ZrCoBi and ZrNiBi are brittle. The band structure and density of states of the present compounds show that ZrCoBi has a semiconducting nature, while Ni-doped ZrCoBi has a half-metallic nature. The structural reforms, brought to ZrCoBi as the Ni-dopant concentration increases at the site of Co-atom, showed an increase in its metallicity, conductivity and ductility, and a decrease in its rigidity, stiffness, minimum thermal conductivity, melting and Debye temperatures. According to the results obtained, ( ZrCo1-xNixBi = 0, 0.25, 0.75 and 1) alloys could have potential thermal and electronic applications.","PeriodicalId":78400,"journal":{"name":"La Ricerca scientifica. 2. ser., pt. 2: Rendiconti. Sezione B: Biologica","volume":"173 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85084005","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 : 2022-06-02DOI: 10.26565/2312-4334-2022-2-20
I. V. Demydenko
The aim of this work is to develop and apply a mathematical apparatus based on nonlinear operators for solving problems of geometric optics, namely the construction of images of objects in systems of thin lenses. The problem of constructing the image of a point in a thin lens was considered, on the basis of which the concept of the lensing operator was defined. The mathematical properties of the operator were investigated. The model problem of constructing an image in thin lenses folded together was investigated, on the basis of which it became possible to establish a physical interpretation of the previously determined properties. The problem of a system of lenses located at a distance was also considered, which resulted in the introduction of the concept of shift operator. The properties of the shift operator were studied, which together with the properties of the lens operator made it possible to determine the rules for using the created operators for solving the problems. In addition to solving the model problems, the following problems were considered: the speed of the moving point image, the magnification factor and the construction of the curve image. As an example, images of a segment and an arc of the circle were constructed. The segment was transformed into the segment, and the arc of the circle into the arc of the curve of the second order. The presented mathematical apparatus is very convenient for implementation in computer programs, as well as for the study of images of different curves.
{"title":"Use of Nonlinear Operators for Solving Geometric Optics Problems","authors":"I. V. Demydenko","doi":"10.26565/2312-4334-2022-2-20","DOIUrl":"https://doi.org/10.26565/2312-4334-2022-2-20","url":null,"abstract":"The aim of this work is to develop and apply a mathematical apparatus based on nonlinear operators for solving problems of geometric optics, namely the construction of images of objects in systems of thin lenses. The problem of constructing the image of a point in a thin lens was considered, on the basis of which the concept of the lensing operator was defined. The mathematical properties of the operator were investigated. The model problem of constructing an image in thin lenses folded together was investigated, on the basis of which it became possible to establish a physical interpretation of the previously determined properties. The problem of a system of lenses located at a distance was also considered, which resulted in the introduction of the concept of shift operator. The properties of the shift operator were studied, which together with the properties of the lens operator made it possible to determine the rules for using the created operators for solving the problems. In addition to solving the model problems, the following problems were considered: the speed of the moving point image, the magnification factor and the construction of the curve image. As an example, images of a segment and an arc of the circle were constructed. The segment was transformed into the segment, and the arc of the circle into the arc of the curve of the second order. The presented mathematical apparatus is very convenient for implementation in computer programs, as well as for the study of images of different curves.","PeriodicalId":78400,"journal":{"name":"La Ricerca scientifica. 2. ser., pt. 2: Rendiconti. Sezione B: Biologica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75226588","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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