Pub Date : 2023-03-22DOI: 10.21303/2461-4262.2023.002809
D. N. K. Putra Negara, I. Widiyarta, I. Suriadi, I. G. K. Dwijana, I. M. D. Budiana Penindra, I. G. N. P. Tenaya, I. K. Sukadana, Anton Saladin Ferdinand
The primary cause of rising CO2 concentrations in the atmosphere is the use of fossil fuels in motor vehicles and factory activities in industry. CO2 levels in the atmosphere can be controlled and reduced by using low-carbon energy and capturing and storing CO2. One widely used way for CO2 capture and storage is adsorption method. This method necessitates the use of an adsorbent, one of which is activated carbon. In this study, brewed coffee waste was converted into activated carbons, characterized, and tested for carbon dioxide adsorption. Brewed coffee waste was dehydrated at 105 ºC for an hour before being carbonized at 550 °C and activated at 670, 700, and 730 °C, with a 200-ml/min nitrogen injection during activation. Activated carbons with activation temperatures of 670, 700, and 730 °C were denoted as AC-670, AC-700, and AC-730, respectively. A series of TGA, SEM, and adsorption isotherm tests were used to determine the proximate components, surface morphology, and surface structure of the activated carbons produced. To assess the adsorption capacities of activated carbon on CO2, the gravimetric CO2 adsorption isotherm method was used. According to the findings of the study, increasing activation temperatures cause variable properties in activated carbon. When using an activation temperature of 700 °C, the most appropriate properties of activated carbon can be obtained. It has 425.843 m2/g specific surface area, 0.345 cm3/g pore volume, 3.423 nm pore diameter, 235.628 cm3/g nitrogen adsorption capacity, and 4.183 mmol/g CO2 adsorption performance. This study provided a simple way converting brewed coffee waste into activated carbon with excellent performance for CO2 adsorption
{"title":"Development of mesoporous activated carbons derived from brewed coffee waste for CO2 adsorption","authors":"D. N. K. Putra Negara, I. Widiyarta, I. Suriadi, I. G. K. Dwijana, I. M. D. Budiana Penindra, I. G. N. P. Tenaya, I. K. Sukadana, Anton Saladin Ferdinand","doi":"10.21303/2461-4262.2023.002809","DOIUrl":"https://doi.org/10.21303/2461-4262.2023.002809","url":null,"abstract":"The primary cause of rising CO2 concentrations in the atmosphere is the use of fossil fuels in motor vehicles and factory activities in industry. CO2 levels in the atmosphere can be controlled and reduced by using low-carbon energy and capturing and storing CO2. One widely used way for CO2 capture and storage is adsorption method. This method necessitates the use of an adsorbent, one of which is activated carbon. In this study, brewed coffee waste was converted into activated carbons, characterized, and tested for carbon dioxide adsorption. Brewed coffee waste was dehydrated at 105 ºC for an hour before being carbonized at 550 °C and activated at 670, 700, and 730 °C, with a 200-ml/min nitrogen injection during activation. Activated carbons with activation temperatures of 670, 700, and 730 °C were denoted as AC-670, AC-700, and AC-730, respectively. A series of TGA, SEM, and adsorption isotherm tests were used to determine the proximate components, surface morphology, and surface structure of the activated carbons produced. To assess the adsorption capacities of activated carbon on CO2, the gravimetric CO2 adsorption isotherm method was used. According to the findings of the study, increasing activation temperatures cause variable properties in activated carbon. When using an activation temperature of 700 °C, the most appropriate properties of activated carbon can be obtained. It has 425.843 m2/g specific surface area, 0.345 cm3/g pore volume, 3.423 nm pore diameter, 235.628 cm3/g nitrogen adsorption capacity, and 4.183 mmol/g CO2 adsorption performance. This study provided a simple way converting brewed coffee waste into activated carbon with excellent performance for CO2 adsorption","PeriodicalId":11804,"journal":{"name":"EUREKA: Physics and Engineering","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89399120","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 : 2023-03-22DOI: 10.21303/2461-4262.2023.002813
A. I. Siswantara, M. Syafei, M. A. Budiyanto, C. D. Widiawaty, Adi Syuriadi, T. A. Farhan, S. Permana
As the largest palm oil producer in the world, Indonesia has a promising potential to produce green fuel through the Fluid Catalytic Cracking (FCC) process. A novel FCC configuration, FCC Proto X 3, which combines a riser reactor and downer reactor in the system, has been developed. However, several valves including in the FCC system remain a black box to the flow distribution in the system. The objective of this paper is to investigate the effect of the valve setting variation on the airflow distribution of the FCC system. The methodology uses experiment and acausal modeling. The effect of valve setting variation on pressure and average velocity of the airflow has been investigated. The experiment is conducted under cold test conditions, while the acausal model of the FCC system is built by using OpenModelica. It is obtained that valve 2 which controls the flow at the channel toward the regenerator is essential due to its role in controlling the air supply combustion process in the regenerator and driving the spent catalyst particles to the regenerator. Valve 3 is responsible for controlling the flow toward the riser reactor directly. Later, it is responsible for supplying the lifting fluid to support the catalytic cracking reaction at the riser sections. Valve 4 contributes to controlling the lifting fluid to the downer reactor. It will also be responsible for supplying thermal energy from the high-temperature particle catalyst to the reactor. When all valves toward the regenerator and reactor are 100 % open, the measured average velocity at the flue gas outlet and the product outlet are 8.04 m/s and 5.775 m/s respectively. The result shows that the airflow at the FCC system tends to flow through the regenerator. The atomic model estimation also shows a similar trend to the experiment result
作为世界上最大的棕榈油生产国，印度尼西亚具有通过流体催化裂化(FCC)工艺生产绿色燃料的巨大潜力。一种新型的FCC配置，FCC Proto x3，在系统中结合了一个提升反应器和一个下行反应器。然而，包括FCC系统在内的几个阀门对于系统中的流量分布仍然是一个黑匣子。本文的目的是研究阀门设置变化对催化裂化系统气流分布的影响。方法采用实验和因果模型。研究了阀门设置变化对气流压力和平均流速的影响。实验是在冷试验条件下进行的，而FCC系统的因果模型是使用OpenModelica建立的。结果表明，控制通道流向蓄热器的阀2是必不可少的，因为它在控制蓄热器内的送风燃烧过程和将废催化剂颗粒驱动到蓄热器中起着重要作用。阀门3负责直接控制流向立管反应堆的流量。随后，它负责提供提升液，以支持立管段的催化裂化反应。阀门4用于控制进入下行反应堆的提升流体。它还将负责从高温颗粒催化剂向反应器提供热能。当所有通向蓄热器和反应器的阀门100%打开时，在烟气出口和产品出口测得的平均速度分别为8.04 m/s和5.775 m/s。结果表明，催化裂化系统内气流有向蓄热器流动的趋势。原子模型估计也显示出与实验结果相似的趋势
{"title":"Flow distribution analysis of a novel fcc system through experiment study and atomic model","authors":"A. I. Siswantara, M. Syafei, M. A. Budiyanto, C. D. Widiawaty, Adi Syuriadi, T. A. Farhan, S. Permana","doi":"10.21303/2461-4262.2023.002813","DOIUrl":"https://doi.org/10.21303/2461-4262.2023.002813","url":null,"abstract":"As the largest palm oil producer in the world, Indonesia has a promising potential to produce green fuel through the Fluid Catalytic Cracking (FCC) process. A novel FCC configuration, FCC Proto X 3, which combines a riser reactor and downer reactor in the system, has been developed. However, several valves including in the FCC system remain a black box to the flow distribution in the system. The objective of this paper is to investigate the effect of the valve setting variation on the airflow distribution of the FCC system. The methodology uses experiment and acausal modeling. The effect of valve setting variation on pressure and average velocity of the airflow has been investigated. The experiment is conducted under cold test conditions, while the acausal model of the FCC system is built by using OpenModelica. It is obtained that valve 2 which controls the flow at the channel toward the regenerator is essential due to its role in controlling the air supply combustion process in the regenerator and driving the spent catalyst particles to the regenerator. Valve 3 is responsible for controlling the flow toward the riser reactor directly. Later, it is responsible for supplying the lifting fluid to support the catalytic cracking reaction at the riser sections. Valve 4 contributes to controlling the lifting fluid to the downer reactor. It will also be responsible for supplying thermal energy from the high-temperature particle catalyst to the reactor. When all valves toward the regenerator and reactor are 100 % open, the measured average velocity at the flue gas outlet and the product outlet are 8.04 m/s and 5.775 m/s respectively. The result shows that the airflow at the FCC system tends to flow through the regenerator. The atomic model estimation also shows a similar trend to the experiment result","PeriodicalId":11804,"journal":{"name":"EUREKA: Physics and Engineering","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81713303","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 : 2023-03-22DOI: 10.21303/2461-4262.2023.002728
F. C. Wibowo, Ade Nur Maemunah, H. Nasbey, B. Coştu, B. Prahani, Niki Dian Permana, D. R. Darman, A. Samsudin
Students' understanding to learn science on the concept of light refraction is experiencing serious problems because of the unobservable of light particles. The research object to be resolved in this study is to improve the concept of light refraction using a photodiode sensor. The problem to be solved in this research is to develop a Simple Kit (SK) Refraction of Light (RoL) using a photodiode sensor for students' understanding of concepts. The research method for making SK RoL using photodiode sensors using ADDIE, which consists of the first stage, analysis by analyzing the needs of SK RoL products using photodiode sensors to be developed. Second, the SK RoL design uses a photodiode sensor. Third, Development is developing SK RoL Using Photodiode Sensors. Implementation of the Fourth RoL Decree Using Photodiode Sensors to see student understanding of 74 students from tertiary institutions in one of the provinces in Indonesia. Fifth, Evaluation by revising the product at each stage of SK RoL development. SK RoL product research results include Green Laser, Photodiode sensor, Angle Arc, Display Module and Displayed Data, Arduino Uno R3 Atmega 328, Medium Container and Programs Using Arduino Software. The characteristics of the SK ROL results show that the SK RoL based on the Photodiode Sensor developed can be used as a physics learning medium because it can visualize the unobservable concept of light refraction and increase students' understanding of the concept of light refraction because of the nature of the particles which are difficult to understand by using a green laser which is passed through a photodiode sensor medium and Arduino can be visualized in a real way. SK RoL can work optimally in a room where the light is not too bright or requires a room that is a bit dark so it is possible to observe the laser beam. SK RoL, as a physics learning medium, can be used to increase students' understanding of the concept of light refraction. The implications of developing SK RoL can be used as a learning medium to attract students' interest in learning, support the learning process, and help make it easier for students to understand abstract physics concepts
{"title":"Development of simple kits (SK) refraction of light using photodiode sensors for student understanding","authors":"F. C. Wibowo, Ade Nur Maemunah, H. Nasbey, B. Coştu, B. Prahani, Niki Dian Permana, D. R. Darman, A. Samsudin","doi":"10.21303/2461-4262.2023.002728","DOIUrl":"https://doi.org/10.21303/2461-4262.2023.002728","url":null,"abstract":"Students' understanding to learn science on the concept of light refraction is experiencing serious problems because of the unobservable of light particles. The research object to be resolved in this study is to improve the concept of light refraction using a photodiode sensor. The problem to be solved in this research is to develop a Simple Kit (SK) Refraction of Light (RoL) using a photodiode sensor for students' understanding of concepts. The research method for making SK RoL using photodiode sensors using ADDIE, which consists of the first stage, analysis by analyzing the needs of SK RoL products using photodiode sensors to be developed. Second, the SK RoL design uses a photodiode sensor. Third, Development is developing SK RoL Using Photodiode Sensors. Implementation of the Fourth RoL Decree Using Photodiode Sensors to see student understanding of 74 students from tertiary institutions in one of the provinces in Indonesia. Fifth, Evaluation by revising the product at each stage of SK RoL development. SK RoL product research results include Green Laser, Photodiode sensor, Angle Arc, Display Module and Displayed Data, Arduino Uno R3 Atmega 328, Medium Container and Programs Using Arduino Software. The characteristics of the SK ROL results show that the SK RoL based on the Photodiode Sensor developed can be used as a physics learning medium because it can visualize the unobservable concept of light refraction and increase students' understanding of the concept of light refraction because of the nature of the particles which are difficult to understand by using a green laser which is passed through a photodiode sensor medium and Arduino can be visualized in a real way. SK RoL can work optimally in a room where the light is not too bright or requires a room that is a bit dark so it is possible to observe the laser beam. SK RoL, as a physics learning medium, can be used to increase students' understanding of the concept of light refraction. The implications of developing SK RoL can be used as a learning medium to attract students' interest in learning, support the learning process, and help make it easier for students to understand abstract physics concepts","PeriodicalId":11804,"journal":{"name":"EUREKA: Physics and Engineering","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89380572","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 : 2023-03-22DOI: 10.21303/2461-4262.2023.002684
W. Suprapto, Y. Irawan, S. Suparman, Muhammad Rafi Amrullah, Pratama Auliasyah, Aditya Rafi Ramdhani
This study aims to control the characterization and mechanical properties of smelting Al-Cu Alloy through Hold-Melt Time. This research uses aluminum scrap and copper wire scrap to produce quality as-cast ingots, clean the environment, and increase waste utilization. Copper melting point of 1083 °C is immersed in molten aluminum at a temperature of 900 °C for 10–30 minutes causing copper to dissolve in aluminum due to smelting events based on diffusion phenomena. Parameters of temperature and immersion time of copper in molten aluminum in this study are expressed by hold-melt time. In the copper aluminum alloy trade, commonly called Duralumin, it is commonly used for impact loads and is heat-treatable. Resistance to cryogenic temperatures, in the future Duralumin has the potential to replace stainless steel. This study used an electric resistance furnace with the specifications for smelting aluminum 3 kg, electric power 2.5–3.0 kW, electric voltage 220 Volts, maximum temperature 1000 °C. It had been conducted an experiment where copper had been melted under its melting point in duralumin ingot casting. In this study, copper pieces were soaked in liquid aluminum with temperature of 900 °C. After 10–30 minutes of holding melt, the soaked copper became Al-Cu alloys and was called molten Duralumin. After the molten duralumin had been cleaned from dross, it was poured into ingot casting. From specific weight test, more soaking time of the copper in liquid aluminum caused specific weight of ingot duralumin increase from 47.08 % to 57.56 % and its hardness increase from 93 to 113 BHN. This study contributes on melting energy saving and improves the characteristic and hardness of ingot aluminum type 2xxx
{"title":"The effect of hold-melt time of micro-regime precipitation size and hardness in Al-Cu alloy","authors":"W. Suprapto, Y. Irawan, S. Suparman, Muhammad Rafi Amrullah, Pratama Auliasyah, Aditya Rafi Ramdhani","doi":"10.21303/2461-4262.2023.002684","DOIUrl":"https://doi.org/10.21303/2461-4262.2023.002684","url":null,"abstract":"This study aims to control the characterization and mechanical properties of smelting Al-Cu Alloy through Hold-Melt Time. This research uses aluminum scrap and copper wire scrap to produce quality as-cast ingots, clean the environment, and increase waste utilization. Copper melting point of 1083 °C is immersed in molten aluminum at a temperature of 900 °C for 10–30 minutes causing copper to dissolve in aluminum due to smelting events based on diffusion phenomena. Parameters of temperature and immersion time of copper in molten aluminum in this study are expressed by hold-melt time. In the copper aluminum alloy trade, commonly called Duralumin, it is commonly used for impact loads and is heat-treatable. Resistance to cryogenic temperatures, in the future Duralumin has the potential to replace stainless steel. This study used an electric resistance furnace with the specifications for smelting aluminum 3 kg, electric power 2.5–3.0 kW, electric voltage 220 Volts, maximum temperature 1000 °C. It had been conducted an experiment where copper had been melted under its melting point in duralumin ingot casting. In this study, copper pieces were soaked in liquid aluminum with temperature of 900 °C. After 10–30 minutes of holding melt, the soaked copper became Al-Cu alloys and was called molten Duralumin. After the molten duralumin had been cleaned from dross, it was poured into ingot casting. From specific weight test, more soaking time of the copper in liquid aluminum caused specific weight of ingot duralumin increase from 47.08 % to 57.56 % and its hardness increase from 93 to 113 BHN. This study contributes on melting energy saving and improves the characteristic and hardness of ingot aluminum type 2xxx","PeriodicalId":11804,"journal":{"name":"EUREKA: Physics and Engineering","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75207599","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 : 2023-03-22DOI: 10.21303/2461-4262.2023.002673
Bui Thanh Danh, N. Van Cuong
The article presents briefly findings in researching methods for determining dynamic stress of the bars in the main structure of gantry crane installed on the cap of bridge pier to install and launch SUPER-T girder. In order to study the dynamic stresses in the bars of the main truss structure of the gantry, the author first had to build a dynamic model, using Matlap software to solve the problem of dynamics with two cases cargo lowering combination combines braking and moving of gantry with cargo to find out the rules and values of dynamic cable tension, dynamic inertial force ( time-varying force), then consider these forces is the external force acting on the main truss structure model of the gantry, from which the author calculates the value of internal force and stress of each bar corresponding to the value of dynamic cable tension and corresponding dynamic inertia force. with two adverse working cases of the gantry. Using Matlap software to calculate the author has obtained a graph of internal force, stress changes over time of each bar in the main truss steel structure of the gantry. The findings of the research provided methods for determining the dynamic stress of the bars in the main structure of gantry crane, pointed out values and rules of change of the dynamic stress of the bars in the main structure of gantry crane. The findings of the research may be used to calculate fatigue, life-span of the main steel structures as well as other parts of the gantry crane
{"title":"Research of methods for determining dynamic stress of the bars in the main structure of gantry crane installed on the cap of bridge pier to serve installation of Super-T girder","authors":"Bui Thanh Danh, N. Van Cuong","doi":"10.21303/2461-4262.2023.002673","DOIUrl":"https://doi.org/10.21303/2461-4262.2023.002673","url":null,"abstract":"The article presents briefly findings in researching methods for determining dynamic stress of the bars in the main structure of gantry crane installed on the cap of bridge pier to install and launch SUPER-T girder. In order to study the dynamic stresses in the bars of the main truss structure of the gantry, the author first had to build a dynamic model, using Matlap software to solve the problem of dynamics with two cases cargo lowering combination combines braking and moving of gantry with cargo to find out the rules and values of dynamic cable tension, dynamic inertial force ( time-varying force), then consider these forces is the external force acting on the main truss structure model of the gantry, from which the author calculates the value of internal force and stress of each bar corresponding to the value of dynamic cable tension and corresponding dynamic inertia force. with two adverse working cases of the gantry. Using Matlap software to calculate the author has obtained a graph of internal force, stress changes over time of each bar in the main truss steel structure of the gantry. The findings of the research provided methods for determining the dynamic stress of the bars in the main structure of gantry crane, pointed out values and rules of change of the dynamic stress of the bars in the main structure of gantry crane. The findings of the research may be used to calculate fatigue, life-span of the main steel structures as well as other parts of the gantry crane","PeriodicalId":11804,"journal":{"name":"EUREKA: Physics and Engineering","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78131400","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 : 2023-03-22DOI: 10.21303/2461-4262.2023.002735
A. Khaldjigitov, Umidjon Djumayozov, Otajon Tilovov
The main parameters characterizing the process of deformation of solids are displacements, strain and stress tensors. From the point of view of the strength and reliability of the structure and its elements, researchers and engineers are mainly interested in the distribution of stresses in the objects under study. Unfortunately, all boundary value problems are formulated and solved in solid mechanics mainly with respect to displacements, or an additional stress functions. And the required stresses are calculated from known displacements or stress functions. In this case, the accuracy of stress calculation is strongly affected by the error of numerical differentiation, as well as the approximation order of the boundary conditions. The formulation of boundary value problems directly with respect to stresses or strains allows to increase the accuracy of stress calculation by bypassing the process of numerical differentiation. Therefore, the present work is devoted to the formulation and numerical solution of boundary value problems directly with respect to stresses and strains. Using the well-known Beltrami-Miеchell equation, and considering the equilibrium equation as ah additional boundary condition, a boundary value problem(BVP) is formulated directly with respect to stresses. In a similar way, using the strain compatibility condition, the Beltrami-Mitchell type equations for strains are written. The finite difference equations for two-dimensional BVP are constructed and written in convenient a form for the use of iterative method. A number of problems on the equilibrium of a rectangular plate under the action of various loads applied on opposite sides are numerically solved. The reliability of the results is ensured by comparing the numerical results of the 2D elasticity problems in stresses and strains, and with the exact solution, as well as with the known solutions of the plate tension problem under parabolic and uniformly distributed loads
{"title":"A new approach to numerical simulation of boundary value problems of the theory of elasticity in stresses and strains","authors":"A. Khaldjigitov, Umidjon Djumayozov, Otajon Tilovov","doi":"10.21303/2461-4262.2023.002735","DOIUrl":"https://doi.org/10.21303/2461-4262.2023.002735","url":null,"abstract":"The main parameters characterizing the process of deformation of solids are displacements, strain and stress tensors. From the point of view of the strength and reliability of the structure and its elements, researchers and engineers are mainly interested in the distribution of stresses in the objects under study. Unfortunately, all boundary value problems are formulated and solved in solid mechanics mainly with respect to displacements, or an additional stress functions. And the required stresses are calculated from known displacements or stress functions. In this case, the accuracy of stress calculation is strongly affected by the error of numerical differentiation, as well as the approximation order of the boundary conditions. The formulation of boundary value problems directly with respect to stresses or strains allows to increase the accuracy of stress calculation by bypassing the process of numerical differentiation. \u0000Therefore, the present work is devoted to the formulation and numerical solution of boundary value problems directly with respect to stresses and strains. Using the well-known Beltrami-Miеchell equation, and considering the equilibrium equation as ah additional boundary condition, a boundary value problem(BVP) is formulated directly with respect to stresses. In a similar way, using the strain compatibility condition, the Beltrami-Mitchell type equations for strains are written. \u0000The finite difference equations for two-dimensional BVP are constructed and written in convenient a form for the use of iterative method. A number of problems on the equilibrium of a rectangular plate under the action of various loads applied on opposite sides are numerically solved. The reliability of the results is ensured by comparing the numerical results of the 2D elasticity problems in stresses and strains, and with the exact solution, as well as with the known solutions of the plate tension problem under parabolic and uniformly distributed loads","PeriodicalId":11804,"journal":{"name":"EUREKA: Physics and Engineering","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80700743","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 : 2023-03-22DOI: 10.21303/2461-4262.2023.002810
W. Wibowo, A. Setyawan, Y. Purwana, B. Setiawan
The use of various types of rigid pavement is widespread because of its superiority in resisting heavy load vehicles. However, traffic loading complexity and subgrade response cause uncertainty during the design process. The presence of water in expansive soil issue swelling affected the flexural behavior of a rigid pavement slab. Rigid pavement relies heavily on the support and stability of the subgrade. Plain concrete is very weak in resisting tensile stresses so that the failure of rigid pavement slab structures often occurs in the expansive subgrade zone. Therefore, this study aims to numerically analyze the relationship between variations in the thickness of rigid pavement slabs on the flexural behavior parameters, such as critical and tensile stresses that affected water in expansive soil. The concrete’s performance limit was determined, using its material’s constitutive equation curve, and the data were analyzed using the finite element method. The results showed that the presence of water in expansive soil caused a change in soil volume (swelling), a reduction in soil bearing capacity (shrinking), and consequently, a rigid pavement cracked due to water variations in the subgrade. Generally, increasing the thickness of rigid pavement is a common method for mitigating the detrimental effects of expansive soil swelling. It is possible to provide reinforcement in other forms, which provide an opportunity to improve the performance of the concrete slab as a rigid pavement. For example, stabilization of expansive soil with materials capable of reducing its expansive power can be done but it requires large resources to realize it. Another method is to provide reinforcement to the rigid pavement slab structure, so that the rigid pavement slab is able to withstand traffic loads and also the expansion and shrinkage behavior of the expansive soil
{"title":"Critical stress evaluation of rigid pavement due to the presence of water in expansive soil subgrade","authors":"W. Wibowo, A. Setyawan, Y. Purwana, B. Setiawan","doi":"10.21303/2461-4262.2023.002810","DOIUrl":"https://doi.org/10.21303/2461-4262.2023.002810","url":null,"abstract":"The use of various types of rigid pavement is widespread because of its superiority in resisting heavy load vehicles. However, traffic loading complexity and subgrade response cause uncertainty during the design process. The presence of water in expansive soil issue swelling affected the flexural behavior of a rigid pavement slab. Rigid pavement relies heavily on the support and stability of the subgrade. Plain concrete is very weak in resisting tensile stresses so that the failure of rigid pavement slab structures often occurs in the expansive subgrade zone. Therefore, this study aims to numerically analyze the relationship between variations in the thickness of rigid pavement slabs on the flexural behavior parameters, such as critical and tensile stresses that affected water in expansive soil. The concrete’s performance limit was determined, using its material’s constitutive equation curve, and the data were analyzed using the finite element method. The results showed that the presence of water in expansive soil caused a change in soil volume (swelling), a reduction in soil bearing capacity (shrinking), and consequently, a rigid pavement cracked due to water variations in the subgrade. Generally, increasing the thickness of rigid pavement is a common method for mitigating the detrimental effects of expansive soil swelling. It is possible to provide reinforcement in other forms, which provide an opportunity to improve the performance of the concrete slab as a rigid pavement. For example, stabilization of expansive soil with materials capable of reducing its expansive power can be done but it requires large resources to realize it. Another method is to provide reinforcement to the rigid pavement slab structure, so that the rigid pavement slab is able to withstand traffic loads and also the expansion and shrinkage behavior of the expansive soil","PeriodicalId":11804,"journal":{"name":"EUREKA: Physics and Engineering","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73194408","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 : 2023-03-22DOI: 10.21303/2461-4262.2023.002731
Novruzova Sudaba, I. Aliyev, Fariz Ahmad
Since most of the fields in the Absheron peninsula of the Republic of Azerbaijan are at the final stage of development, an inevitable reduction in hydrocarbon production is expected. An increase in the proportion of formation water in well production, the presence of intra-reservoir, annulus and other cross-flows in this region, in most cases, is associated with inefficient isolation work. The development of effective recipes for cement slurries with controlled rheological properties is relevant. Natural zeolite was used as an additive to control the rheological properties of cement slurries. A feature of zeolites is the presence of a system of regular channels and communicating cavities capable of holding ions, atoms and molecules of substances, whose size corresponds to the size of free space. Zeolite (clinoptilolite) has the following properties: adsorption ‒ the ability to absorb and release various substances; ion exchange ‒ the ability to exchange cations; catalytic ‒ the ability to speed up chemical reactions. In addition, clinoptilolite has a molecular sieve effect that transmits (filtration) and absorbs molecules of various substances selectively. In the course of experiments, the effects of zeolite dispersions on the physicochemical parameters of cement stone were studied. When regulating the rheological properties of cement slurries with zeolite additives, it is necessary to determine the effect of thermobaric factors on the values of these properties. In studies to assess the effect of temperature on the rheological properties of zeolite-cement mortars, they were carried out for the temperature range of 25÷75 ℃
{"title":"Study of the influence of thermobaric conditions on the rheological characteristics of plugging solutions for insulation works","authors":"Novruzova Sudaba, I. Aliyev, Fariz Ahmad","doi":"10.21303/2461-4262.2023.002731","DOIUrl":"https://doi.org/10.21303/2461-4262.2023.002731","url":null,"abstract":"Since most of the fields in the Absheron peninsula of the Republic of Azerbaijan are at the final stage of development, an inevitable reduction in hydrocarbon production is expected. An increase in the proportion of formation water in well production, the presence of intra-reservoir, annulus and other cross-flows in this region, in most cases, is associated with inefficient isolation work. \u0000The development of effective recipes for cement slurries with controlled rheological properties is relevant. Natural zeolite was used as an additive to control the rheological properties of cement slurries. A feature of zeolites is the presence of a system of regular channels and communicating cavities capable of holding ions, atoms and molecules of substances, whose size corresponds to the size of free space. \u0000Zeolite (clinoptilolite) has the following properties: adsorption ‒ the ability to absorb and release various substances; ion exchange ‒ the ability to exchange cations; catalytic ‒ the ability to speed up chemical reactions. In addition, clinoptilolite has a molecular sieve effect that transmits (filtration) and absorbs molecules of various substances selectively. In the course of experiments, the effects of zeolite dispersions on the physicochemical parameters of cement stone were studied. When regulating the rheological properties of cement slurries with zeolite additives, it is necessary to determine the effect of thermobaric factors on the values of these properties. In studies to assess the effect of temperature on the rheological properties of zeolite-cement mortars, they were carried out for the temperature range of 25÷75 ℃","PeriodicalId":11804,"journal":{"name":"EUREKA: Physics and Engineering","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87558810","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 : 2023-03-22DOI: 10.21303/2461-4262.2023.002814
B. Isakulov, H. Abdullaev, Almagul Mukasheva, Uzakbai Akishev, Gulsaira Ordabayeva
The creation of the slag-alkaline arbolite's structure is examined in this study, which is based on measurements of the deformation of the mortar component, contact zone, and filler. Composites made of slag and alkaline arbolite are among the lightest building materials available, with excellent sound insulation and low thermal conductivity. Standard measuring equipment and procedures for analyzing the chemical and physico-mechanical properties of slag-alkaline arbolite composites were employed during the experimental tests. All of the test samples were light concrete prisms with a cross section of 150x150 mm and a length of 600 mm. For comparison, one portion of the samples was constructed of slag-alkaline Portland cement, and the other portion was made of slag-alkaline binder with crushed cotton stem fibers as an organic component. The durability and deformability of arbolite were tested under Kazakhstan weather conditions and in standard hardening chambers. The arbolite underwent a compression stress that ranged from (0.3 to 0.75) Rbn of prismatic strength. It was discovered that the organic cellulose filler added to the slag-alkaline binder based on crushed cotton stalk fiber, which makes up to 70 % of the volume, has a major impact on the way structures are formed. The system becomes rigid, the elasticity changes, and the acoustic properties in this case will fix both physical and physico-chemical processes when a porous organic filler is added. The acquired results can be applied to the creation of efficient wall materials for civil buildings, including seismic zones
{"title":"Investigation of the formation of microstructure and strength characteristics of slag-alkaline arbolite","authors":"B. Isakulov, H. Abdullaev, Almagul Mukasheva, Uzakbai Akishev, Gulsaira Ordabayeva","doi":"10.21303/2461-4262.2023.002814","DOIUrl":"https://doi.org/10.21303/2461-4262.2023.002814","url":null,"abstract":"The creation of the slag-alkaline arbolite's structure is examined in this study, which is based on measurements of the deformation of the mortar component, contact zone, and filler. Composites made of slag and alkaline arbolite are among the lightest building materials available, with excellent sound insulation and low thermal conductivity. Standard measuring equipment and procedures for analyzing the chemical and physico-mechanical properties of slag-alkaline arbolite composites were employed during the experimental tests. All of the test samples were light concrete prisms with a cross section of 150x150 mm and a length of 600 mm. For comparison, one portion of the samples was constructed of slag-alkaline Portland cement, and the other portion was made of slag-alkaline binder with crushed cotton stem fibers as an organic component. The durability and deformability of arbolite were tested under Kazakhstan weather conditions and in standard hardening chambers. The arbolite underwent a compression stress that ranged from (0.3 to 0.75) Rbn of prismatic strength. It was discovered that the organic cellulose filler added to the slag-alkaline binder based on crushed cotton stalk fiber, which makes up to 70 % of the volume, has a major impact on the way structures are formed. The system becomes rigid, the elasticity changes, and the acoustic properties in this case will fix both physical and physico-chemical processes when a porous organic filler is added. The acquired results can be applied to the creation of efficient wall materials for civil buildings, including seismic zones","PeriodicalId":11804,"journal":{"name":"EUREKA: Physics and Engineering","volume":"54 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76894220","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 : 2023-03-22DOI: 10.21303/2461-4262.2023.002647
Aris Ansori, S. Soeparman, D. Widhiyanuriyawan, T. Widodo
The utilization of biopolymers for energy applications continues to attract researchers, due to the unique properties of biopolymers that are easily modified, such as cassava starch (CS) biopolymer that has hydroxyl molecular chains. However, the brittle, and non-waterproof nature of starch films is an obstacle to their use in triboelectric nanogenerator (TENG) solid-solid films. This study aims to improve the physicochemical properties of cassava starch films by modifying them into nanocomposite films. The nanocomposite film was made from 70:30 CS/polyvinyl alcohol (PVA) composite and variation of TiO2 nanoparticles addition using solvent casting method. The results showed that the mechanical properties of cassava starch film increased with the addition of PVA. Meanwhile, the addition of TiO2 above 1 wt % of the mechanical properties of the film tends to decrease. The film has low wettability properties with a contact angle of 83.6°. The performance of the nanocomposite film as a Rotary disc freestanding film (RDF-TENG) produces 4.4-fold the output voltage and 2.8-fold the current compared to the film without TiO2. This is a new finding that the CS/PVA-TiO2 nanocomposite film has the potential for TENG films in high-humidity environmental conditions
{"title":"Enhanced mechanical and water resistance properties of cassava starch-PVA composites with TiO2 nanofillers for triboelectric nanogenerators films","authors":"Aris Ansori, S. Soeparman, D. Widhiyanuriyawan, T. Widodo","doi":"10.21303/2461-4262.2023.002647","DOIUrl":"https://doi.org/10.21303/2461-4262.2023.002647","url":null,"abstract":"The utilization of biopolymers for energy applications continues to attract researchers, due to the unique properties of biopolymers that are easily modified, such as cassava starch (CS) biopolymer that has hydroxyl molecular chains. However, the brittle, and non-waterproof nature of starch films is an obstacle to their use in triboelectric nanogenerator (TENG) solid-solid films. This study aims to improve the physicochemical properties of cassava starch films by modifying them into nanocomposite films. The nanocomposite film was made from 70:30 CS/polyvinyl alcohol (PVA) composite and variation of TiO2 nanoparticles addition using solvent casting method. The results showed that the mechanical properties of cassava starch film increased with the addition of PVA. Meanwhile, the addition of TiO2 above 1 wt % of the mechanical properties of the film tends to decrease. The film has low wettability properties with a contact angle of 83.6°. The performance of the nanocomposite film as a Rotary disc freestanding film (RDF-TENG) produces 4.4-fold the output voltage and 2.8-fold the current compared to the film without TiO2. This is a new finding that the CS/PVA-TiO2 nanocomposite film has the potential for TENG films in high-humidity environmental conditions","PeriodicalId":11804,"journal":{"name":"EUREKA: Physics and Engineering","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85977657","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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