Elena Danila | Technical University of Iasi (original) (raw)

Papers by Elena Danila

Research paper thumbnail of Energy Management in a Laboratory Computer Grid Energy Management in a Laboratory Computer Grid

Research paper thumbnail of Autonomy improvement of data center backup sources with supercapacitors

Research paper thumbnail of How artificial lighting can become a health issue

Research paper thumbnail of On Electro-Dewatering a Cellulosic Sludge

Environmental Engineering and Management Journal

The paper describes in brief the electro-osmosis process and reviews the possibility to use it in... more The paper describes in brief the electro-osmosis process and reviews the possibility to use it in dewatering the pulp and paper waste sludge. The waste sludge main characteristics and dewatering methods from the Vrancart SA factory are revealed. After the experimental method and test bench description, some results from the preliminary laboratory tests on the Vrancart SA sludge are presented and discussed.

Research paper thumbnail of Efficient lighting system for greenhouses

2016 International Conference and Exposition on Electrical and Power Engineering (EPE), 2016

Research paper thumbnail of Lens impact investigation on photometric parameters of some LED luminaires for exterior lighting

2016 International Conference on Applied and Theoretical Electricity (ICATE), 2016

Research paper thumbnail of Supercapacitors and Risk Reduction in Energy Supply

Research paper thumbnail of Risks in Change Management of Engineering Higher Education

Research paper thumbnail of History of the First Energy Storage Systems

Research paper thumbnail of Efficiency of Some Growing Light Systems for Tomatoes

Research paper thumbnail of How artificial lighting can become a health issue

Academia Letters, 2021

It has been found in recent years, both empirically and scientifically, that artificial light pro... more It has been found in recent years, both empirically and scientifically, that artificial light produces certain changes on living organisms (humans, plants, animals), under conditions of improper exposure. As lighting (environmental, residential, artificial, display, architectural, industrial) is indispensable to modern life, the question arises: can this exposure be limited or adapted? Given that urban development tends to be vertical, and future smart buildings must include all the elements of the classic environment, artificial lighting will be not only a utility, but also an element of aesthetics and comfort. Vertical urbanism, from underground to the clouds, has to concentrate homes, offices, shops, restaurants, parks, even streets, with obvious benefits for working people, for the environment that can regenerate around. These aspects also pay special attention to the side effects, regarding artificial lighting. The increase of urban concentration also brings the increase of intensive lighting, implicitly to light pollution (in any of its form-urban sky glow, light trespass, glare, over-illumination, clutter). The latest advances in photobiological science led to discoveries that will impose changes in lighting recommendations, in both medical and technical fields. According to the new approach and principles of healthy lighting, the sources with a dominant wavelength in the interval (450-480, 500) nm, present the higher values of circadian efficiency. In circadian terms, the melanopic lux is the photometric measure characterizing how the retinal photoreceptors (melanopsin-containing cells) which provide the major input to the circadian pacemaker react to light. It has been demonstrated that blue light can reduce drowsiness (so increase readiness), being proper for the ambient lighting during the day, but blue with minimum brightness as at half brightness it provides high quantal irradiance value. Here must be considered that humans are also spending day and night a lot of time using IT devices that emit blue light. In the corresponding range of the electromagnetic spectrum blue light has a lot of energy (3.10 eV) at which our biological system is really sensitive to. These considerations serve as

Research paper thumbnail of Improving Quality of Learning During Laboratory Works by Using Preformed Reports

Nowadays, a lot of factors are affecting the quality of learning, especially in the case of techn... more Nowadays, a lot of factors are affecting the quality of learning, especially in the case of technical disciplines. The principal stress factors are: the rather poor quality and involvement of the students, the need to work simultaneously with large number of students for the practical applications, the necessity to provide a measurable way of the students' work assessment. The paper aim is to share and discuss the experience gained by the authors during the laboratory hours to the discipline " Utilizations of Electric Energy " through the use of preformed labs' report.

Research paper thumbnail of Cost Effectiveness of Growing Plant Lighting System

Since plants are biologically-based and since controlled environment plant production demands sig... more Since plants are biologically-based and since controlled environment plant production demands significant electrical-energy inputs, the paper propose an economic comparative analysis on four growing plant lighting systems (fluorescent, metal halides, high pressure sodium and LED), in order to determine the most efficient type of lamp that can be used in a specific crop or greenhouse. As every investment in crop production has the implicit aim to reduce the electrical-power load required for plant production and to harvest as much, the analysis took into account the cost components. There were not taken into account the expenditures of heating plants in winter. There is demonstrated that the best long term investment is in LED lighting system, as predictable. Further, this study was conducted in accordance with all European norms and sustainable strategies.

Research paper thumbnail of High energy saving for africa street lighting using individual automatic dimming of HID ballasts

2014 International Conference and Exposition on Electrical and Power Engineering (EPE), 2014

Research paper thumbnail of Runtime optimization of hybrid energy source from an UPS back-upping critical consumer

2014 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM), 2014

ABSTRACT The vulnerability of electricity consumers must be decreased by integrating specific ene... more ABSTRACT The vulnerability of electricity consumers must be decreased by integrating specific energy storage systems, which can be used in any situation. As energy distribution and consumption are not constant, the storage units (for backup) must be as high capacity and total availability to streamline the complete system. This paper proposes an objective function of charging an UPS integrated hybrid source (battery and supercapacitor) and a method for optimizing the supply of loads in a critical place of consumption through the UPS with hybrid structure, increasing the autonomy of backup source and its time of re-entry into service.

Research paper thumbnail of Hybrid backup power source behaviour in a microgrid

2014 International Conference and Exposition on Electrical and Power Engineering (EPE), 2014

ABSTRACT By their nature, microgrids are dependent on the continuity of power supply and require ... more ABSTRACT By their nature, microgrids are dependent on the continuity of power supply and require backup sources with the highest degree of efficiency and availability. In addition, most users connected to a low voltage network have individual loads or groups of receivers that need quality energy supply (higher than those offered by the public grid) and they also require backup power source. The availability, redundancy, resiliency and effectiveness of a hybrid backup source (with batteries and supercapacitors) were analyzed in this paper by physical modeling a critical consumer. Experimental stand, scaled 1:9.5, is centered on supercapacitors' storage system, which supplies critical consumer in parallel with two batteries. Load profile obtained both with supplying through the converter and without control discharge, reflecting a very good coverage of energy demand.

Research paper thumbnail of Dynamic modelling of supercapacitor using artificial neural network technique

2014 International Conference and Exposition on Electrical and Power Engineering (EPE), 2014

ABSTRACT Because of the complex dynamic behavior of supercapacitor, its modeling must be based on... more ABSTRACT Because of the complex dynamic behavior of supercapacitor, its modeling must be based on parallel, distributed structures (each component has to represent a model of activity, distributed on many processing units), with learning capacity. For this purpose, the paper proposes a new feed forward artificial neural network structure with two hidden layers and with backpropagation training. The neural network provides, after activation, training, testing and reinitializing, output values with a total correlation of 0, 9426 compared with target values.

Research paper thumbnail of Models and Modelling the Supercapacitors for a Defined Application

elth.ucv.ro

Supercapacitors, located in the middle of the energy storage devices' hierarchy, present unique a... more Supercapacitors, located in the middle of the energy storage devices' hierarchy, present unique advantages that make them indispensable for applications which require high power delivered in a short time. Establishing the appropriateness of strategies for using these devices is through knowing the supercapacitor's behavior in different loads and its control. Starting from the establishment of a mathematicaleconometric model that allows the supercapacitor characteristics' optimization and of a basic electrical equivalent model, the paper presents the realization of a new complex, adaptive model of a supercapacitor, used as a storage device and power supply, taking into account temperature influences on key parameters, the effect of high frequencies on the capacitance and the effects of aging based on application-specific usage. Based on thorough analysis of the classic measurements that are made in pre-choosing a type of supercapacitor to perform the function of an energy source in a system and taking into account all the above factors that may influence the behavior of a supercapacitor, the new electrical equivalent, conceptually model is tested and validated by successive simulations using dedicated software. The model is stable during the simulation and the size of the error to the measured value does not exceed 2.1% of nominal voltage. The solution is even more important as the power supply system must ensure continuity all operating conditions.

Research paper thumbnail of PV Power Source Estimation for a Custom-Designed Growing-Plant Lighting System

When solar radiation meets the leaf of a plant, there occur three optical phenomena: reflection (... more When solar radiation meets the leaf of a plant, there occur three optical phenomena: reflection (~10%), transmission (~27%) and absorption (~63%). In photosynthesis, the emitted spectrum by a lighting source (natural or electric) is not entirely used by plants, only the radiation in the range of 400 -480nm (blue and purple) and 580 -680nm (red and orange). The artificial light can stimulate the crop production, in specific conditions and with a very careful system design, considering both energetic and biologic aspects. The paper opens a broad interdisciplinary study direction, also actual -as the management of food resources in the world becomes a serious problem, and the deeper integration of technology in agriculture is no longer a trend but a necessity. The paper assess the use of PV panels to supply the growing-plant lighting systems placed in protected or far areas where the grid is absent, as a green power source alternative.

Research paper thumbnail of Energy Management in a Laboratory Computer Grid Energy Management in a Laboratory Computer Grid

Research paper thumbnail of Autonomy improvement of data center backup sources with supercapacitors

Research paper thumbnail of How artificial lighting can become a health issue

Research paper thumbnail of On Electro-Dewatering a Cellulosic Sludge

Environmental Engineering and Management Journal

The paper describes in brief the electro-osmosis process and reviews the possibility to use it in... more The paper describes in brief the electro-osmosis process and reviews the possibility to use it in dewatering the pulp and paper waste sludge. The waste sludge main characteristics and dewatering methods from the Vrancart SA factory are revealed. After the experimental method and test bench description, some results from the preliminary laboratory tests on the Vrancart SA sludge are presented and discussed.

Research paper thumbnail of Efficient lighting system for greenhouses

2016 International Conference and Exposition on Electrical and Power Engineering (EPE), 2016

Research paper thumbnail of Lens impact investigation on photometric parameters of some LED luminaires for exterior lighting

2016 International Conference on Applied and Theoretical Electricity (ICATE), 2016

Research paper thumbnail of Supercapacitors and Risk Reduction in Energy Supply

Research paper thumbnail of Risks in Change Management of Engineering Higher Education

Research paper thumbnail of History of the First Energy Storage Systems

Research paper thumbnail of Efficiency of Some Growing Light Systems for Tomatoes

Research paper thumbnail of How artificial lighting can become a health issue

Academia Letters, 2021

It has been found in recent years, both empirically and scientifically, that artificial light pro... more It has been found in recent years, both empirically and scientifically, that artificial light produces certain changes on living organisms (humans, plants, animals), under conditions of improper exposure. As lighting (environmental, residential, artificial, display, architectural, industrial) is indispensable to modern life, the question arises: can this exposure be limited or adapted? Given that urban development tends to be vertical, and future smart buildings must include all the elements of the classic environment, artificial lighting will be not only a utility, but also an element of aesthetics and comfort. Vertical urbanism, from underground to the clouds, has to concentrate homes, offices, shops, restaurants, parks, even streets, with obvious benefits for working people, for the environment that can regenerate around. These aspects also pay special attention to the side effects, regarding artificial lighting. The increase of urban concentration also brings the increase of intensive lighting, implicitly to light pollution (in any of its form-urban sky glow, light trespass, glare, over-illumination, clutter). The latest advances in photobiological science led to discoveries that will impose changes in lighting recommendations, in both medical and technical fields. According to the new approach and principles of healthy lighting, the sources with a dominant wavelength in the interval (450-480, 500) nm, present the higher values of circadian efficiency. In circadian terms, the melanopic lux is the photometric measure characterizing how the retinal photoreceptors (melanopsin-containing cells) which provide the major input to the circadian pacemaker react to light. It has been demonstrated that blue light can reduce drowsiness (so increase readiness), being proper for the ambient lighting during the day, but blue with minimum brightness as at half brightness it provides high quantal irradiance value. Here must be considered that humans are also spending day and night a lot of time using IT devices that emit blue light. In the corresponding range of the electromagnetic spectrum blue light has a lot of energy (3.10 eV) at which our biological system is really sensitive to. These considerations serve as

Research paper thumbnail of Improving Quality of Learning During Laboratory Works by Using Preformed Reports

Nowadays, a lot of factors are affecting the quality of learning, especially in the case of techn... more Nowadays, a lot of factors are affecting the quality of learning, especially in the case of technical disciplines. The principal stress factors are: the rather poor quality and involvement of the students, the need to work simultaneously with large number of students for the practical applications, the necessity to provide a measurable way of the students' work assessment. The paper aim is to share and discuss the experience gained by the authors during the laboratory hours to the discipline " Utilizations of Electric Energy " through the use of preformed labs' report.

Research paper thumbnail of Cost Effectiveness of Growing Plant Lighting System

Since plants are biologically-based and since controlled environment plant production demands sig... more Since plants are biologically-based and since controlled environment plant production demands significant electrical-energy inputs, the paper propose an economic comparative analysis on four growing plant lighting systems (fluorescent, metal halides, high pressure sodium and LED), in order to determine the most efficient type of lamp that can be used in a specific crop or greenhouse. As every investment in crop production has the implicit aim to reduce the electrical-power load required for plant production and to harvest as much, the analysis took into account the cost components. There were not taken into account the expenditures of heating plants in winter. There is demonstrated that the best long term investment is in LED lighting system, as predictable. Further, this study was conducted in accordance with all European norms and sustainable strategies.

Research paper thumbnail of High energy saving for africa street lighting using individual automatic dimming of HID ballasts

2014 International Conference and Exposition on Electrical and Power Engineering (EPE), 2014

Research paper thumbnail of Runtime optimization of hybrid energy source from an UPS back-upping critical consumer

2014 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM), 2014

ABSTRACT The vulnerability of electricity consumers must be decreased by integrating specific ene... more ABSTRACT The vulnerability of electricity consumers must be decreased by integrating specific energy storage systems, which can be used in any situation. As energy distribution and consumption are not constant, the storage units (for backup) must be as high capacity and total availability to streamline the complete system. This paper proposes an objective function of charging an UPS integrated hybrid source (battery and supercapacitor) and a method for optimizing the supply of loads in a critical place of consumption through the UPS with hybrid structure, increasing the autonomy of backup source and its time of re-entry into service.

Research paper thumbnail of Hybrid backup power source behaviour in a microgrid

2014 International Conference and Exposition on Electrical and Power Engineering (EPE), 2014

ABSTRACT By their nature, microgrids are dependent on the continuity of power supply and require ... more ABSTRACT By their nature, microgrids are dependent on the continuity of power supply and require backup sources with the highest degree of efficiency and availability. In addition, most users connected to a low voltage network have individual loads or groups of receivers that need quality energy supply (higher than those offered by the public grid) and they also require backup power source. The availability, redundancy, resiliency and effectiveness of a hybrid backup source (with batteries and supercapacitors) were analyzed in this paper by physical modeling a critical consumer. Experimental stand, scaled 1:9.5, is centered on supercapacitors' storage system, which supplies critical consumer in parallel with two batteries. Load profile obtained both with supplying through the converter and without control discharge, reflecting a very good coverage of energy demand.

Research paper thumbnail of Dynamic modelling of supercapacitor using artificial neural network technique

2014 International Conference and Exposition on Electrical and Power Engineering (EPE), 2014

ABSTRACT Because of the complex dynamic behavior of supercapacitor, its modeling must be based on... more ABSTRACT Because of the complex dynamic behavior of supercapacitor, its modeling must be based on parallel, distributed structures (each component has to represent a model of activity, distributed on many processing units), with learning capacity. For this purpose, the paper proposes a new feed forward artificial neural network structure with two hidden layers and with backpropagation training. The neural network provides, after activation, training, testing and reinitializing, output values with a total correlation of 0, 9426 compared with target values.

Research paper thumbnail of Models and Modelling the Supercapacitors for a Defined Application

elth.ucv.ro

Supercapacitors, located in the middle of the energy storage devices' hierarchy, present unique a... more Supercapacitors, located in the middle of the energy storage devices' hierarchy, present unique advantages that make them indispensable for applications which require high power delivered in a short time. Establishing the appropriateness of strategies for using these devices is through knowing the supercapacitor's behavior in different loads and its control. Starting from the establishment of a mathematicaleconometric model that allows the supercapacitor characteristics' optimization and of a basic electrical equivalent model, the paper presents the realization of a new complex, adaptive model of a supercapacitor, used as a storage device and power supply, taking into account temperature influences on key parameters, the effect of high frequencies on the capacitance and the effects of aging based on application-specific usage. Based on thorough analysis of the classic measurements that are made in pre-choosing a type of supercapacitor to perform the function of an energy source in a system and taking into account all the above factors that may influence the behavior of a supercapacitor, the new electrical equivalent, conceptually model is tested and validated by successive simulations using dedicated software. The model is stable during the simulation and the size of the error to the measured value does not exceed 2.1% of nominal voltage. The solution is even more important as the power supply system must ensure continuity all operating conditions.

Research paper thumbnail of PV Power Source Estimation for a Custom-Designed Growing-Plant Lighting System

When solar radiation meets the leaf of a plant, there occur three optical phenomena: reflection (... more When solar radiation meets the leaf of a plant, there occur three optical phenomena: reflection (~10%), transmission (~27%) and absorption (~63%). In photosynthesis, the emitted spectrum by a lighting source (natural or electric) is not entirely used by plants, only the radiation in the range of 400 -480nm (blue and purple) and 580 -680nm (red and orange). The artificial light can stimulate the crop production, in specific conditions and with a very careful system design, considering both energetic and biologic aspects. The paper opens a broad interdisciplinary study direction, also actual -as the management of food resources in the world becomes a serious problem, and the deeper integration of technology in agriculture is no longer a trend but a necessity. The paper assess the use of PV panels to supply the growing-plant lighting systems placed in protected or far areas where the grid is absent, as a green power source alternative.