Pub Date : 2022-12-20DOI: 10.56958/jesi.2022.7.4.455
L. Goras, M. Fira
The aim of this communication is to discuss the dynamics of a couple of graphtype circuits that exhibit one or more unstable modes. Examples of finding the sign of un unstable mode as well as mode competition are presented.
{"title":"On unstable modes in graph-type circuits","authors":"L. Goras, M. Fira","doi":"10.56958/jesi.2022.7.4.455","DOIUrl":"https://doi.org/10.56958/jesi.2022.7.4.455","url":null,"abstract":"The aim of this communication is to discuss the dynamics of a couple of graphtype circuits that exhibit one or more unstable modes. Examples of finding the sign of un unstable mode as well as mode competition are presented.","PeriodicalId":52936,"journal":{"name":"Journal of Engineering Sciences and Innovation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47041166","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 : 2022-12-20DOI: 10.56958/jesi.2022.7.4.473
Rachel Apolince Assona Nguefack, J. Mbihi, Bruno Kenfack
This paper presents a novel instrumentation device for instantaneous digital acquisition and processing, of the urine flow absorbed by a textile medium. The proposed device is smart version of a basic instrument studied in previous research works. Arduino framework is used as the development tool of the main C++ instrumentation sketch for ESP32 microchip target. The proposed smart device owes its novelty to many relevant factors including a hardware simplicity of the unary sensor, a multilevel alerting strategy, as well as a multivariable monitoring process. In the wireless side, a serial Bluetooth terminal application is used as driver for smartphone-based virtual monitoring of involved output variables. Furthermore, an experimental workbench built for testing the proposed device is presented. Finally, the technical characteristics and experimental results obtained and presented in the paper, show the innovative nature of the proposed device for bioinstrumentation engineering.
{"title":"A novel smart instrument for multilevel alerting and multivariable monitoring of urinary absorption process into a textile medium","authors":"Rachel Apolince Assona Nguefack, J. Mbihi, Bruno Kenfack","doi":"10.56958/jesi.2022.7.4.473","DOIUrl":"https://doi.org/10.56958/jesi.2022.7.4.473","url":null,"abstract":"This paper presents a novel instrumentation device for instantaneous digital acquisition and processing, of the urine flow absorbed by a textile medium. The proposed device is smart version of a basic instrument studied in previous research works. Arduino framework is used as the development tool of the main C++ instrumentation sketch for ESP32 microchip target. The proposed smart device owes its novelty to many relevant factors including a hardware simplicity of the unary sensor, a multilevel alerting strategy, as well as a multivariable monitoring process. In the wireless side, a serial Bluetooth terminal application is used as driver for smartphone-based virtual monitoring of involved output variables. Furthermore, an experimental workbench built for testing the proposed device is presented. Finally, the technical characteristics and experimental results obtained and presented in the paper, show the innovative nature of the proposed device for bioinstrumentation engineering.","PeriodicalId":52936,"journal":{"name":"Journal of Engineering Sciences and Innovation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47105294","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 : 2022-12-20DOI: 10.56958/jesi.2022.7.4.393
V. Năstăsescu
A current problem, of increased difficulty, which is still under continuous development, is the calculus of functionally graded plates (FGPs). Functionally graded materials (FGMs) represent a special category of composite materials, usually made on the basis of two materials, with very different properties, so they vary continuously between the extreme surfaces of the material, where the properties are those of the respective materials in their pure state. Today, the most used materials used in the construction of FGMs are ceramic materials and metals. Their volume fractions, in the thickness direction, varies continuously, according to a material law, valid for all material properties. A problem, generally poorly substantiated, is the one related to the assumption of a constant value of the Poisson's ratio over the entire plate thickness of the functionally graded plates. This hypothesis admits an analytical solution, by direct integration, of the stiffness of the plate, but it certainly does not reflect reality. There are some ways of approaching the calculation of functionally graded plates, such as the multilayer plate concept or the equivalent plate concept, which can take into account the variation of the Poisson's ratio on the plate thickness. The paper highlights this aspect and, in addition, evaluates the influence of the variation of Poisson's ratio on the calculation of displacements, stresses and natural vibrations of functionally graded plates. The work represents both an original way of approaching the calculation of functionally graded plates and a quantitative substantiation of the hypothesis of a Poisson coefficient with a constant value.
{"title":"The influence of Poisson's ratio in the calculus of functionally graded plates","authors":"V. Năstăsescu","doi":"10.56958/jesi.2022.7.4.393","DOIUrl":"https://doi.org/10.56958/jesi.2022.7.4.393","url":null,"abstract":"A current problem, of increased difficulty, which is still under continuous development, is the calculus of functionally graded plates (FGPs). Functionally graded materials (FGMs) represent a special category of composite materials, usually made on the basis of two materials, with very different properties, so they vary continuously between the extreme surfaces of the material, where the properties are those of the respective materials in their pure state. Today, the most used materials used in the construction of FGMs are ceramic materials and metals. Their volume fractions, in the thickness direction, varies continuously, according to a material law, valid for all material properties. A problem, generally poorly substantiated, is the one related to the assumption of a constant value of the Poisson's ratio over the entire plate thickness of the functionally graded plates. This hypothesis admits an analytical solution, by direct integration, of the stiffness of the plate, but it certainly does not reflect reality. There are some ways of approaching the calculation of functionally graded plates, such as the multilayer plate concept or the equivalent plate concept, which can take into account the variation of the Poisson's ratio on the plate thickness. The paper highlights this aspect and, in addition, evaluates the influence of the variation of Poisson's ratio on the calculation of displacements, stresses and natural vibrations of functionally graded plates. The work represents both an original way of approaching the calculation of functionally graded plates and a quantitative substantiation of the hypothesis of a Poisson coefficient with a constant value.","PeriodicalId":52936,"journal":{"name":"Journal of Engineering Sciences and Innovation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42277570","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 : 2022-12-20DOI: 10.56958/jesi.2022.7.4.463
V. Sima
Many applications from industry and technology use models formulated by systems of differential equations. Often, some equations describe additional algebraic constraints. Such systems, referred to as descriptor systems (or singular systems), naturally arise, e.g., in electrical circuit simulation, in multibody dynamics with constraints, or by semidiscretization of certain partial differential equations. A very important characteristic value for a descriptor system is the L∞-norm of its corresponding transfer function. The computation of this norm is essential in robust control, model order reduction, and other applications. The paper summarizes efficient and reliable algorithms for finding L∞-norm, for continuous- and discrete-time descriptor systems, which exploit the underlying Hamiltonian or symplectic structure, respectively. An improved solver has been developed and will be made available in the SLICOT Library. Numerical results and comparisons illustrate the good performance and effectiveness of this solver.
{"title":"Efficient computation of the L-infinity norm of descriptor systems","authors":"V. Sima","doi":"10.56958/jesi.2022.7.4.463","DOIUrl":"https://doi.org/10.56958/jesi.2022.7.4.463","url":null,"abstract":"Many applications from industry and technology use models formulated by systems of differential equations. Often, some equations describe additional algebraic constraints. Such systems, referred to as descriptor systems (or singular systems), naturally arise, e.g., in electrical circuit simulation, in multibody dynamics with constraints, or by semidiscretization of certain partial differential equations. A very important characteristic value for a descriptor system is the L∞-norm of its corresponding transfer function. The computation of this norm is essential in robust control, model order reduction, and other applications. The paper summarizes efficient and reliable algorithms for finding L∞-norm, for continuous- and discrete-time descriptor systems, which exploit the underlying Hamiltonian or symplectic structure, respectively. An improved solver has been developed and will be made available in the SLICOT Library. Numerical results and comparisons illustrate the good performance and effectiveness of this solver.","PeriodicalId":52936,"journal":{"name":"Journal of Engineering Sciences and Innovation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46318529","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 : 2022-12-20DOI: 10.56958/jesi.2022.7.4.437
D. Lucan, Claudia Samarineanu, G. Jinescu
"The energy transition should be planned with critical materials in mind to avoid unforeseen delays. This planning relates to both supply and demand aspects. Better public data are needed regarding the capacity to ramp up mining of primary materials in the coming years. Also, the potential of innovation to avoid or minimise use of critical materials needs to be better understood. This paper will assess how the growth of different types of energy (including nuclear) will put critical materials at the centre of the energy transformation at the international level, with the objective of highlighting the criticalities related to the sector and of identifying how technological developments and innovation can positively reduce geopolitical risks. For Europe’s ambition to deliver the Green Deal the access to resources is a strategic security question. The EU’s open strategic autonomy in these sectors will therefore need to continue to be anchored in diversified and undistorted access to global markets for raw materials. The paper also presents a case study of the exploitation of Romania natural resources."
{"title":"Critical materials as key factor providing efficiency in energy engineering","authors":"D. Lucan, Claudia Samarineanu, G. Jinescu","doi":"10.56958/jesi.2022.7.4.437","DOIUrl":"https://doi.org/10.56958/jesi.2022.7.4.437","url":null,"abstract":"\"The energy transition should be planned with critical materials in mind to avoid unforeseen delays. This planning relates to both supply and demand aspects. Better public data are needed regarding the capacity to ramp up mining of primary materials in the coming years. Also, the potential of innovation to avoid or minimise use of critical materials needs to be better understood. This paper will assess how the growth of different types of energy (including nuclear) will put critical materials at the centre of the energy transformation at the international level, with the objective of highlighting the criticalities related to the sector and of identifying how technological developments and innovation can positively reduce geopolitical risks. For Europe’s ambition to deliver the Green Deal the access to resources is a strategic security question. The EU’s open strategic autonomy in these sectors will therefore need to continue to be anchored in diversified and undistorted access to global markets for raw materials. The paper also presents a case study of the exploitation of Romania natural resources.\"","PeriodicalId":52936,"journal":{"name":"Journal of Engineering Sciences and Innovation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42464921","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 : 2022-12-20DOI: 10.56958/jesi.2022.7.4.415
C. Munteanu, C. Stescu, D. Chicet, I. Vida-Simiti, B. Istrate, I. Doroftei, Raul George Ciubotariu
Research in the present paper has highlighted the availability of using bronze coatings, obtained by electric arc spray (EAS) method, for the purpose of increasing the life time of materials tested for abrasive sliding wear. The experimental plan of the work includes the analysis of three types of samples: S1 (samples deposited with a CuAl 90-10 layer on a steel-type base material), S2 (casted sample from CuAl9 material) and S3 (bearing material sample). The sliding wear analysis were obtained on a specific testing machine in a lubricated environment (clean oil) at a preset loading, obtaining both the friction coefficient for each material type and the material loss for each sample. The results showed an average strength of the bronze coated sample (S1), its mechanical characteristics being higher to the other two analyzed samples.
{"title":"Study of the wear behavior of bronze coatings deposited by the EAS method","authors":"C. Munteanu, C. Stescu, D. Chicet, I. Vida-Simiti, B. Istrate, I. Doroftei, Raul George Ciubotariu","doi":"10.56958/jesi.2022.7.4.415","DOIUrl":"https://doi.org/10.56958/jesi.2022.7.4.415","url":null,"abstract":"Research in the present paper has highlighted the availability of using bronze coatings, obtained by electric arc spray (EAS) method, for the purpose of increasing the life time of materials tested for abrasive sliding wear. The experimental plan of the work includes the analysis of three types of samples: S1 (samples deposited with a CuAl 90-10 layer on a steel-type base material), S2 (casted sample from CuAl9 material) and S3 (bearing material sample). The sliding wear analysis were obtained on a specific testing machine in a lubricated environment (clean oil) at a preset loading, obtaining both the friction coefficient for each material type and the material loss for each sample. The results showed an average strength of the bronze coated sample (S1), its mechanical characteristics being higher to the other two analyzed samples.","PeriodicalId":52936,"journal":{"name":"Journal of Engineering Sciences and Innovation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43031634","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 : 2022-12-20DOI: 10.56958/jesi.2022.7.4.403
M. Radeṣ
This paper reports experience in using two Componentwise Mode Indicator Functions to locate the modes of vibration of a real structure with sufficiently separated frequencies. The advantages of using selected sets of measurement points and different limited frequency bands are emphasized.
{"title":"Using CoMIFs in structural modal testing","authors":"M. Radeṣ","doi":"10.56958/jesi.2022.7.4.403","DOIUrl":"https://doi.org/10.56958/jesi.2022.7.4.403","url":null,"abstract":"This paper reports experience in using two Componentwise Mode Indicator Functions to locate the modes of vibration of a real structure with sufficiently separated frequencies. The advantages of using selected sets of measurement points and different limited frequency bands are emphasized.","PeriodicalId":52936,"journal":{"name":"Journal of Engineering Sciences and Innovation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41576507","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 : 2022-12-20DOI: 10.56958/jesi.2022.7.4.427
I. Haruna, I. Rufai, Dalhatu Balarabe Yayaya
The hybrid downdraft evaporative cooler (HDEC) conditions a building by cooling with humidification and hence, inappropriate location of its supply outlet on a building facade has a great impact on the indoor air quality (IAQ) which affect the health, concentration, and productivity of the occupants. This paper investigates the effect of the height of the HDEC supply outlet on the IAQ of an office building equipped with the HDEC system in Bayero University Kano. The building model was created using DesignBuilder software while DesignBuilder CFD was employed for the parametric simulation using air change effectiveness (ACE) as the performance criterion. The height of the HDEC supply outlet was varyfrom 0.1m to 2.4m step 0.1m above the floor level. The results show that higher values of ACE in the occupants’ breathing zone were obtained at lower heights of the HDEC supply outlets with the best ACE of 1.1588 obtained at 0.3m. This information could help engineers to optimally position the HDEC supply outlet on the façade of an office building or any other building with similar characteristics.
{"title":"Effects of the height of supply outlet of façade-mounted hybrid downdraft evaporative cooler on the indoor air quality of an office building","authors":"I. Haruna, I. Rufai, Dalhatu Balarabe Yayaya","doi":"10.56958/jesi.2022.7.4.427","DOIUrl":"https://doi.org/10.56958/jesi.2022.7.4.427","url":null,"abstract":"The hybrid downdraft evaporative cooler (HDEC) conditions a building by cooling with humidification and hence, inappropriate location of its supply outlet on a building facade has a great impact on the indoor air quality (IAQ) which affect the health, concentration, and productivity of the occupants. This paper investigates the effect of the height of the HDEC supply outlet on the IAQ of an office building equipped with the HDEC system in Bayero University Kano. The building model was created using DesignBuilder software while DesignBuilder CFD was employed for the parametric simulation using air change effectiveness (ACE) as the performance criterion. The height of the HDEC supply outlet was varyfrom 0.1m to 2.4m step 0.1m above the floor level. The results show that higher values of ACE in the occupants’ breathing zone were obtained at lower heights of the HDEC supply outlets with the best ACE of 1.1588 obtained at 0.3m. This information could help engineers to optimally position the HDEC supply outlet on the façade of an office building or any other building with similar characteristics.","PeriodicalId":52936,"journal":{"name":"Journal of Engineering Sciences and Innovation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44472731","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 : 2022-09-14DOI: 10.56958/jesi.2022.7.3.387
C. Berbente, S. Berbente, Marius Brebenel
In a previous paper [3] we have used the hydrodynamic analogy to give a model for gravity. A carrying particle named HD-graviton was introduced. In another paper [8], a hydrodynamic analog permitted to unify the theory to include the Coulomb force using so called “vortex masses” having as hydrodynamical correspondent the vortices. In this paper we will give a hydrodynamic interpretation to the YUKAWA (nuclear) interaction. We remember that the hydrodynamical analog for the electrical charges are the vortices.
{"title":"A possible way to unify the electrostatic (Coulomb) and nuclear (Yukawa) interactions by using a hydrodynamic analogy","authors":"C. Berbente, S. Berbente, Marius Brebenel","doi":"10.56958/jesi.2022.7.3.387","DOIUrl":"https://doi.org/10.56958/jesi.2022.7.3.387","url":null,"abstract":"In a previous paper [3] we have used the hydrodynamic analogy to give a model for gravity. A carrying particle named HD-graviton was introduced. In another paper [8], a hydrodynamic analog permitted to unify the theory to include the Coulomb force using so called “vortex masses” having as hydrodynamical correspondent the vortices. In this paper we will give a hydrodynamic interpretation to the YUKAWA (nuclear) interaction. We remember that the hydrodynamical analog for the electrical charges are the vortices.","PeriodicalId":52936,"journal":{"name":"Journal of Engineering Sciences and Innovation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48830558","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 : 2022-09-14DOI: 10.56958/jesi.2022.7.3.373
D. G. Zisopol, A. Dumitrescu, M. Minescu, M. Bădicioiu, M. Călțaru
The present paper describes the equipment conceived, designed and built by the authors, during a complex research program, in order to perform the tests required for the quality assessment of the permanent assembly technologies used within the natural gas installations made of copper pipes. The research work addressed below is part of our effort (detailed in a separate paper [1]) aiming at making possible the use, within the natural gas installations in Romania (alongside steel and polyethylene pipes), of copper pipes assembled using the press fit technology, by aligning the Romanian standards to the European ones. The equipment described in the paper can be used to investigate the dynamic strength under torsion loads, the dynamic strength under bending loads (vibrations) and the operating capacity at high temperature of the joints and fittings for copper pipes.
{"title":"Equipment for quality assessment of the copper pipes and fittings used within natural gas installations","authors":"D. G. Zisopol, A. Dumitrescu, M. Minescu, M. Bădicioiu, M. Călțaru","doi":"10.56958/jesi.2022.7.3.373","DOIUrl":"https://doi.org/10.56958/jesi.2022.7.3.373","url":null,"abstract":"The present paper describes the equipment conceived, designed and built by the authors, during a complex research program, in order to perform the tests required for the quality assessment of the permanent assembly technologies used within the natural gas installations made of copper pipes. The research work addressed below is part of our effort (detailed in a separate paper [1]) aiming at making possible the use, within the natural gas installations in Romania (alongside steel and polyethylene pipes), of copper pipes assembled using the press fit technology, by aligning the Romanian standards to the European ones. The equipment described in the paper can be used to investigate the dynamic strength under torsion loads, the dynamic strength under bending loads (vibrations) and the operating capacity at high temperature of the joints and fittings for copper pipes.","PeriodicalId":52936,"journal":{"name":"Journal of Engineering Sciences and Innovation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45501163","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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