ELECTRICAL AND STRUCTURAL CHARACTERIZATION OF FEW-LAYER GRAPHENE SHEETS ON QUARTZ

Despite the impressive performance and incredible promise for a variety of applications, the wide-scale commercialization of graphene is still behind its full potential. One of the main challenges is related to preserving graphene’s unique properties upon transfer onto practically desirable substrates. In this work, few-layer graphene sheets deposited via liquid-phase transfer from copper onto a quartz substrate have been studied using a suite of experimental techniques, including scanning electron microscopy (SEM), Raman spectroscopy, admittance spectroscopy, and four-point probe electrical measurements. SEM measurements suggest that the transfer of graphene from copper foil to quartz using the aqueous solution of ammonium persulfate was accompanied by unintentional etching of the entire surface of the quartz substrate and, as a result, the formation of microscopic facet structures covering the etched surface of the substrate. As revealed by Raman spectroscopy and the electrical measurements, the transfer process involving the etching of the copper foil in a 0.1Msolution of (NH4)2S2O8 resulted in its p-type doping. This was accompanied by the appearance of an electronic gap of 0.022 eV, as evidenced by the Arrhenius analysis. The observed increase in the conductance of the samples with temperature can be explained by thermally activated carrier transport, dominating the scattering processes

Characterization of a Heterojunction Silicon Solar Cell by Means of Impedance Spectroscopy

Impedance spectroscopy provides relevant knowledge on the recombination and extraction of photogenerated charge carriers in various types of photovoltaic devices. In particular, this method is of great benefit to the study of crystalline silicon (c-Si)-based solar cells, a market-dominating commercial technology, for example, in terms of the comparison of various types of c-Si devices. This study investigates the dark and light electrophysical characteristics of a heterojunction silicon solar cell fabricated using plasma-enhanced chemical vapor deposition. The measurements are performed at various applied biases, enabling the determination of complex resistance, characteristic time, capacitive response and impurity concentration within the semiconductor junction and to correlate them with the device performance. In addition, the impedance spectra of the studied cell were investigated as a function of temperature. Studies of the frequency and temperature dependences of capacitance do not reveal a significant presence of thermally activated centers of free carrier capture, concomitant with a very small value of the activation energy extracted from an Arrhenius-type analysis. This leads to a conclusion that these centers are likely not impactful on the device operation and efficiency

Renovation of multi-story old building in downtown

Deterioration of old buildings in urban areas due to outdated structural, geotechnical, and architectural designs calls for the need of renovation in order to reuse those buildings. Renovation is becoming an effective way to extend service life of aging buildings, which are emerging as a crucial factor effecting resident’s wellbeing. Through performing renovation structure’s service live is extended, the living condition of its residents is improved, sustainable design is implemented, as well as structural strength, architectural and geotechnical designs are improved. For this project, a Soviet Union 5-storey precast concrete panel building located in the downtown area of Astana is chosen for renovation. The renovation includes downwards and upwards extension of the structure, namely construction of 2-storey underground parking and additional 2 storeys on existing building. Due to increased gravity load from additional storeys, the existing structure’s walls, slabs and connections between them are going to be strengthened and the old foundation is planned to be replaced to support the load of the new 7-storey structure and 2-storey underground parking. The project scope includes architectural modification of the structure’s exterior design presented as a 3D model in SketchUp software. The architectural plan of existing building is presented in AutoCAD drawings. As the entire project is performed based on American codes and the existing structure is constructed based on Soviet Union codes, the consistency of the existing structure’s space use and occupancy is checked and verified to be in an agreement with American codes. The data on interior environment, ceiling and flooring of the existing structure is collected and described in architectural design section. The modifications, in addition to construction of the parking and 2 storeys, also include construction of elevators, the selection and design of which is also described in architectural design section. The structural design includes analysis of existing building’s structural elements, specifically their strength and ability to withstand additional loads from upward modification, and the procedure and results of strengthening details. In order to proceed in this, design loads, which include dead, live, snow and wind loads, were calculated. Then, 3D model was built in SAP2000 software, from which internal design loads for each wall, slab and connections were obtained. Additionally, the internal design loads of specific members for one vertical and one horizontal case were calculated manually. The values obtained from SAP2000 for these cases and manual calculations were compared and verified. In addition to this, lateral drift analysis and check under wind load was performed. Based on the data on existing building’s structural members, namely reinforcement detailing, the design strength of each wall is calculated and presented in the form of M-N interaction curve. Design strengths of walls and joints are also calculated. From this analysis of design load and design strength, it is ensured that strengthening is not required as the walls, slabs and joints are able to sustain additional loads from vertical extension. Structural detailing of all members are provided in AutoCAD drawings. The geotechnical design was initiated by collecting data on soil profile of the region where the building is located. Based on the load from the structure, parking columns, slabs, micropiles and micropile connections are designed. Due to foundation replacement and excavation, dewatering is performed. Excavation process is designed in Plaxis to determine the settlement and ensure that it is within allowable limit. Sheet piles are also designed in Plaxis, as well as new foundation. The project management section involves the scope of the project, risk assessment and mitigation plan, health and safety plan, waste management plan, cost and time estimations, and risk management. Additionally, detailed Work Breakdown Structure and scheduling are prepared

Renovation of multi-story old building in downtown

Deterioration of old buildings in urban areas due to outdated structural, geotechnical, and architectural designs calls for the need of renovation in order to reuse those buildings. Renovation is becoming an effective way to extend service life of aging buildings, which are emerging as a crucial factor effecting resident’s wellbeing. Through performing renovation structure’s service live is extended, the living condition of its residents is improved, sustainable design is implemented, as well as structural strength, architectural and geotechnical designs are improved. For this project, a Soviet Union 5-storey precast concrete panel building located in the downtown area of Astana is chosen for renovation. The renovation includes downwards and upwards extension of the structure, namely construction of 2-storey underground parking and additional 2 storeys on existing building. Due to increased gravity load from additional storeys, the existing structure’s walls, slabs and connections between them are going to be strengthened and the old foundation is planned to be replaced to support the load of the new 7-storey structure and 2-storey underground parking. The project scope includes architectural modification of the structure’s exterior design presented as a 3D model in SketchUp software. The architectural plan of existing building is presented in AutoCAD drawings. As the entire project is performed based on American codes and the existing structure is constructed based on Soviet Union codes, the consistency of the existing structure’s space use and occupancy is checked and verified to be in an agreement with American codes. The data on interior environment, ceiling and flooring of the existing structure is collected and described in architectural design section. The modifications, in addition to construction of the parking and 2 storeys, also include construction of elevators, the selection and design of which is also described in architectural design section. The structural design includes analysis of existing building’s structural elements, specifically their strength and ability to withstand additional loads from upward modification, and the procedure and results of strengthening details. In order to proceed in this, design loads, which include dead, live, snow and wind loads, were calculated. Then, 3D model was built in SAP2000 software, from which internal design loads for each wall, slab and connections were obtained. Additionally, the internal design loads of specific members for one vertical and one horizontal case were calculated manually. The values obtained from SAP2000 for these cases and manual calculations were compared and verified. In addition to this, lateral drift analysis and check under wind load was performed. Based on the data on existing building’s structural members, namely reinforcement detailing, the design strength of each wall is calculated and presented in the form of M-N interaction curve. Design strengths of walls and joints are also calculated. From this analysis of design load and design strength, it is ensured that strengthening is not required as the walls, slabs and joints are able to sustain additional loads from vertical extension. Structural detailing of all members are provided in AutoCAD drawings. The geotechnical design was initiated by collecting data on soil profile of the region where the building is located. Based on the load from the structure, parking columns, slabs, micropiles and micropile connections are designed. Due to foundation replacement and excavation, dewatering is performed. Excavation process is designed in Plaxis to determine the settlement and ensure that it is within allowable limit. Sheet piles are also designed in Plaxis, as well as new foundation. The project management section involves the scope of the project, risk assessment and mitigation plan, health and safety plan, waste management plan, cost and time estimations, and risk management. Additionally, detailed Work Breakdown Structure and scheduling are prepared

Integrating augmented reality technology to enhance student's learning in physical education

In practically every professional sport, the usage of linked computerized performances and monitoring components, data analysis, augmented and virtual reality are standard things. Augmented reality in sporting is being shaped by the interaction of devices and information and communication technology advances. Nevertheless, without analysis, the data collected are useless. In the sporting industry, scientists and researchers are becoming more and more essential to human operations. Even if a variety of data, technology, new measurements, and analytics are readily available on our life, most participants in professional sports do not yet show a strong interest in sports analysis. In this study, we explore augmented reality tools in sport activities and consider augmented reality tools to improve health conditions of students at the universities

On the Use of the Loud Platform in the Work of the Scientific and Educational Cluster

The process of designing and creating an integrated distributed information system for storing digitized works of scientists of research institutes of the Almaty academic city is analyzed. The requirements for the storage of digital objects are defined; a comparative analysis of the open source software used for these purposes is carried out. The system fully provides the necessary computing resources for ongoing research and educational processes, simplifying the prospect of its further development, and allows to build an advanced IT infrastructure for managing intellectual capital, an electronic library that is intended to store all books and scientific works of the Kazakhstan Engineering Technological University and research institutes of the Almaty academic city

On the use of the cloud platform in the work of the Scientific and Educational Cluster

The process of designing and creating an integrated distributed information system for storing digitized works of scientists of research institutes of the Almaty academic city is analyzed. The requirements for the storage of digital objects are defined; a comparative analysis of the open source software used for these purposes is carried out. The system fully provides the necessary computing resources for ongoing research and educational processes, simplifying the prospect of its further development, and allows to build an advanced IT infrastructure for managing intellectual capital, an electronic library that is intended to store all books and scientific works of the Kazakhstan Engineering Technological University and research institutes of the Almaty academic city

On the use of the cloud platform in the work of the Scientific and Educational Cluster

The process of designing and creating an integrated distributed information system for storing digitized works of scientists of research institutes of the Almaty academic city is analyzed. The requirements for the storage of digital objects are defined; a comparative analysis of the open source software used for these purposes is carried out. The system fully provides the necessary computing resources for ongoing research and educational processes, simplifying the prospect of its further development, and allows to build an advanced IT infrastructure for managing intellectual capital, an electronic library that is intended to store all books and scientific works of the Kazakhstan Engineering Technological University and research institutes of the Almaty academic city

Mechano-Chemical Properties of Electron Beam Irradiated Polyetheretherketone

In this study, the mechano-chemical properties of aromatic polymer polyetheretherketone (PEEK) samples, irradiated by high energy electrons at 200 and 400 kGy doses, were investigated by Nanoindentation, Brillouin light scattering spectroscopy and Fourier-transform infrared spectroscopy (FTIR). Irradiating electrons penetrated down to a 5 mm depth inside the polymer, as shown numerically by the monte CArlo SImulation of electroN trajectory in sOlids (CASINO) method. The irradiation of PEEK samples at 200 kGy caused the enhancement of surface roughness by almost threefold. However, an increase in the irradiation dose to 400 kGy led to a decrease in the surface roughness of the sample. Most likely, this was due to the processes of erosion and melting of the sample surface induced by high dosage irradiation. It was found that electron irradiation led to a decrease of the elastic constant C11, as well as a slight decrease in the sample’s hardness, while the Young’s elastic modulus decrease was more noticeable. An intrinsic bulk property of PEEK is less radiation resistance than at its surface. The proportionality constant of Young’s modulus to indentation hardness for the pristine and irradiated samples were 0.039 and 0.038, respectively. In addition, a quasi-linear relationship between hardness and Young’s modulus was observed. The degradation of the polymer’s mechanical properties was attributed to electron irradiation-induced processes involving scission of macromolecular chains

Internal exposure to neutron-activated 56Mn dioxide powder in Wistar rats?Part 2: pathological effects

To fully understand the radiation effects of the atomic bombing of Hiroshima and Nagasaki among the survivors, radiation from neutron-induced radioisotopes in soil and other materials should be considered in addition to the initial radiation directly received from the bombs. This might be important for evaluating the radiation risks to the people who moved to these cities soon after the detonations and probably inhaled activated radioactive “dust.” Manganese-56 is known to be one of the dominant radioisotopes produced in soil by neutrons. Due to its short physical half-life, 56Mn emits residual radiation during the first hours after explosion. Hence, the biological effects of internal exposure of Wistar rats to 56Mn were investigated in the present study. MnO2 powder was activated by a neutron beam to produce radioactive 56Mn. Rats were divided into four groups: those exposed to 56Mn, to non-radioactive Mn, to 60Co γ rays (2 Gy, whole body), and those not exposed to any additional radiation (control). On days 3, 14, and 60 after exposure, the animals were killed and major organs were dissected and subjected to histopathological analysis. As described in more detail by an accompanying publication, the highest internal radiation dose was observed in the digestive system of the rats, followed by the lungs. It was found that the number of mitotic cells increased in the small intestine on day 3 after 56Mn and 60Co exposure, and this change persisted only in 56Mn-exposed animals. Lung tissue was severely damaged only by exposure to 56Mn, despite a rather low radiation dose (less than 0.1 Gy). These data suggest that internal exposure to 56Mn has a significant biological impact on the lungs and small intestine