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The transition to a circular economy with an emphasis on eco-innovation is just beginning both in Europe and in Romania, as a member country of the European Union. The whole economic system in which people operate must be circular, which means that it must eliminate conflicting aspects related to regulation, collaboration, governance, supply chain dynamics, and data transparency. However, the barriers to the transition to a circular economy are substantial, and it is up to states to work together to find innovative solutions to society’s problems. This article focuses on aspects related to eco-innovation in the field of drinking water quality in all administrative regions of Romania. In this regard, a study was undertaken, and the main objective pursued in was to identify and highlight the degree of eco-innovation of drinking water suppliers in seven underdeveloped regions of Romania. Starting from an analysis of the water management framework through the OECD Principles on Water Governance, it was possible to develop a study on drinking water supply companies in Romania. This study was performed based on specific indicators grouped by categories, and it aimed in two directions: on the one hand, the identification of drinking water distributors with a high degree of eco-innovation, which leads to quality certification of the drinking water supplied and which has the impact of encouraging household consumers to mainly use this type of supplied water to the detriment of PET bottled water (which has well-known major disadvantages in relation to environmental pollution and user health); on the other hand, the identification of drinking water supply companies with a low degree of eco-innovation, which is proof of the need for mandatory measures to improve drinking water quality, measures that can be taken at the supplier level but especially with support from the administrative and political environment.
Oana-Adriana Crișan; Corina Bîrleanu; Horea-George Crișan; Marius Pustan; Violeta Merie; Florina Șerdean. Eco-Innovation Analyses in the Management of Drinking Water Provided by the Main Suppliers in Romania. International Journal of Environmental Research and Public Health 2021, 18, 6232 .
AMA StyleOana-Adriana Crișan, Corina Bîrleanu, Horea-George Crișan, Marius Pustan, Violeta Merie, Florina Șerdean. Eco-Innovation Analyses in the Management of Drinking Water Provided by the Main Suppliers in Romania. International Journal of Environmental Research and Public Health. 2021; 18 (12):6232.
Chicago/Turabian StyleOana-Adriana Crișan; Corina Bîrleanu; Horea-George Crișan; Marius Pustan; Violeta Merie; Florina Șerdean. 2021. "Eco-Innovation Analyses in the Management of Drinking Water Provided by the Main Suppliers in Romania." International Journal of Environmental Research and Public Health 18, no. 12: 6232.
The COVID pandemic has touched many aspects of everyone’s life. Education is one of the fields greatly affected by it, as students and teachers were forced to move online and quickly adapt to the online environment. Assessment is a crucial part of education, especially in STEM fields. A gap analysis was performed by expert groups in the frame of an Erasmus+ project looking at the practices of six European countries. Specialists teaching university-grade mathematics in seven European institutions were asked about their perception of gaps in the assessment of students both before (2019) and during (2021) the pandemic. This qualitative study looks at the difference in perception of such gaps after almost one year of online teaching. The analysis of their responses showed that some gaps were present before the pandemic, as well as others that are specific to it. Some gaps, such as the lack of IT infrastructure and the need to adapt materials to an online environment, have been exacerbated by the outbreak.
Vlad Bocanet; Ken Brown; Anne Uukkivi; Filomena Soares; Ana Lopes; Anna Cellmer; Carles Serrat; Cristina Feniser; Florina Serdean; Elena Safiulina; Gerald Kelly; Joanna Cymerman; Igor Kierkosz; Volodymyr Sushch; Marina Latõnina; Oksana Labanova; M. Bruguera; Chara Pantazi; M. Estela. Change in Gap Perception within Current Practices in Assessing Students Learning Mathematics. Sustainability 2021, 13, 4495 .
AMA StyleVlad Bocanet, Ken Brown, Anne Uukkivi, Filomena Soares, Ana Lopes, Anna Cellmer, Carles Serrat, Cristina Feniser, Florina Serdean, Elena Safiulina, Gerald Kelly, Joanna Cymerman, Igor Kierkosz, Volodymyr Sushch, Marina Latõnina, Oksana Labanova, M. Bruguera, Chara Pantazi, M. Estela. Change in Gap Perception within Current Practices in Assessing Students Learning Mathematics. Sustainability. 2021; 13 (8):4495.
Chicago/Turabian StyleVlad Bocanet; Ken Brown; Anne Uukkivi; Filomena Soares; Ana Lopes; Anna Cellmer; Carles Serrat; Cristina Feniser; Florina Serdean; Elena Safiulina; Gerald Kelly; Joanna Cymerman; Igor Kierkosz; Volodymyr Sushch; Marina Latõnina; Oksana Labanova; M. Bruguera; Chara Pantazi; M. Estela. 2021. "Change in Gap Perception within Current Practices in Assessing Students Learning Mathematics." Sustainability 13, no. 8: 4495.
The influence of the driving electrode positions on the dynamic response of polysilicon MEMS resonators used in biosensing applications is studied as a function of the operating conditions (vacuum versus free-air operating mode). The scope of this research work is orientated towards identifying the effect of driving electrode position on the dynamic response of sensing MEMS used in biomass detection. The mass-deposition detection is based on the change in the resonant frequency of vibrating elements considering a biological detection film deposited on the oscillating structure. The operating conditions, such as medium pressure, change the behavior of the dynamic response including the resonant frequency, the amplitude, and the velocity of oscillations as well as the quality factor and the loss of energy. The change in the dynamic response of the investigated MEMS cantilevers as a function of the lower electrode position and operating conditions is evaluated using a Polytec Laser Vibrometer. The decrease in the amplitude and velocity of the oscillations if the lower electrode is moved from the beam free-end toward the beam anchor is experimentally monitored. The changes in the response of samples in vacuum are slightly influenced by the electrode position compared with the response of the same sample in ambient conditions. Moreover, the effect of oscillating modes (first, second and third modes) is taken into consideration to improve the dynamical detection of the investigated samples. The obtained results indicate that different responses of MEMS resonators can be achieved if the position of the driving electrode is moved from the cantilever free-end toward the anchor. Indeed, the resonator stiffness, velocity and amplitude of oscillations are significantly modified for samples oscillating in ambient conditions for biological detection compared with their response in vacuum.
Marius Pustan; Corina Birleanu; Florina Serdean. Dynamic Characterization of Biosensing MEMS Cantilevers with Different Position of the Driving Electrode—Vacuum Response Versus Ambient Conditions. Engineering Proceedings 2021, 4, 30 .
AMA StyleMarius Pustan, Corina Birleanu, Florina Serdean. Dynamic Characterization of Biosensing MEMS Cantilevers with Different Position of the Driving Electrode—Vacuum Response Versus Ambient Conditions. Engineering Proceedings. 2021; 4 (1):30.
Chicago/Turabian StyleMarius Pustan; Corina Birleanu; Florina Serdean. 2021. "Dynamic Characterization of Biosensing MEMS Cantilevers with Different Position of the Driving Electrode—Vacuum Response Versus Ambient Conditions." Engineering Proceedings 4, no. 1: 30.
Ceramic materials have properties such as: high hardness; high ratio between mechanical resistance/density, wear and corrosion resistance; high stability to the action of corrosive agents; and relatively low price. However, the use of technical ceramics has a rather limited area, determined essentially by its tribo-mechanical behavior. The machine parts may fail and not fulfill their functional role due to some limit factors. This paper is based on the behavior of aluminum ceramics in terms of stress and strain in the contact area, and the tribological behavior of these materials. A mathematical concept, including multi-objective optimization based on the cuckoo search algorithm of breaking ceramic materials in which there are defects in the form of internal cracks, has been developed. A defect criterion has been formulated to allow the evaluation of the propagation of the semicircular crack which shapes the places where there are natural defects in the ceramic mass. The model highlighted is the contact between two curved surfaces, specific to the ball–ring contact in the bearings. It has highlighted tensions stress and the stress factors, taking into account the coefficient of conformity and the influence of the friction effects. The experimental study of the mechanical stress state in the contact areas was carried out with the ceramic friction couple ball-bearing ring (Al2O3—99.7% with the addition of SiO2, Fe2O and MgO). A large number of experimental tests were performed. The results of this research work are useful for mechanical designers to identify the crack effect on mechanical parts’ lifetime and to improve reliability.
Corina Birleanu; Marius Pustan; Florina Serdean. The Internal Cracks’ Influence on The Stress Behavior of Al2O3 Tribo-Mechanical System Under Contact Pressures. Engineering Proceedings 2021, 4, 28 .
AMA StyleCorina Birleanu, Marius Pustan, Florina Serdean. The Internal Cracks’ Influence on The Stress Behavior of Al2O3 Tribo-Mechanical System Under Contact Pressures. Engineering Proceedings. 2021; 4 (1):28.
Chicago/Turabian StyleCorina Birleanu; Marius Pustan; Florina Serdean. 2021. "The Internal Cracks’ Influence on The Stress Behavior of Al2O3 Tribo-Mechanical System Under Contact Pressures." Engineering Proceedings 4, no. 1: 28.
The goal of this paper is to introduce a technique of creating self-tests that has allowed to actively incorporate university students into the learning process. The study was conducted within the framework of the Erasmus+ Project EngiMath. Partners’ peer reviews, the survey results and the students’ comments in forums and test results were used to conduct the research. The students’ overall satisfaction was in a high level. However, opportunities for some technical improvement has been emerged like the formulation of the tasks needs to be very clear and the time required to perform the tests must be limited. The following conclusions can be drawn from the study. The use of self-tests at all stages of training has intensified the assimilation of the material, i.e. increased understanding of theoretical material and developed computational skills. By completing a series of such assignments on each topic of the course, students had mastered the methodology of studying the topic and mastered specific teaching material on this topic. Feedback made, taking into account typical errors, has allowed the students to analyse their knowledge. A large number of variations for such tasks has allowed students to be involved in the process of active independent and individualized self-study.
Oksana Labanova; Elena Safiulina; Marina Latõnina; Anne Uukkivi; Vlad Bocanet; Cristina Feniser; Florina Serdean; Ana Paula Lopes; Filomena Soares; Ken Brown; Gerald Kelly; Errol Martin; Anna Cellmer; Joanna Cymerman; Volodymyr Sushch; Igor Kierkosz; Javier Bilbao; Eugenio Bravo; Olatz Garcia; Concepción Varela; Carolina Rebollar. Poster: Technique of Active Online Training: Lessons Learnt from EngiMath Project. Advances in Intelligent Systems and Computing 2021, 721 -729.
AMA StyleOksana Labanova, Elena Safiulina, Marina Latõnina, Anne Uukkivi, Vlad Bocanet, Cristina Feniser, Florina Serdean, Ana Paula Lopes, Filomena Soares, Ken Brown, Gerald Kelly, Errol Martin, Anna Cellmer, Joanna Cymerman, Volodymyr Sushch, Igor Kierkosz, Javier Bilbao, Eugenio Bravo, Olatz Garcia, Concepción Varela, Carolina Rebollar. Poster: Technique of Active Online Training: Lessons Learnt from EngiMath Project. Advances in Intelligent Systems and Computing. 2021; ():721-729.
Chicago/Turabian StyleOksana Labanova; Elena Safiulina; Marina Latõnina; Anne Uukkivi; Vlad Bocanet; Cristina Feniser; Florina Serdean; Ana Paula Lopes; Filomena Soares; Ken Brown; Gerald Kelly; Errol Martin; Anna Cellmer; Joanna Cymerman; Volodymyr Sushch; Igor Kierkosz; Javier Bilbao; Eugenio Bravo; Olatz Garcia; Concepción Varela; Carolina Rebollar. 2021. "Poster: Technique of Active Online Training: Lessons Learnt from EngiMath Project." Advances in Intelligent Systems and Computing , no. : 721-729.
Symmetry plays an essential role for generating aesthetic forms. The curve is the basic element used by designers to obtain aesthetic forms. A curve with a linear logarithmic curvature graph gradient is called aesthetic curve. The aesthetic value of a curve increases when its gradient is close to a straight line. We introduce the notions of approximate aesthetic curves and approximate neutral curves and obtain estimations between the curvature of an approximate aesthetic/neutral curve and an aesthetic curve.
Ioana Crăciun; Dorian Popa; Florina Serdean; Lucian Tudose. On Approximate Aesthetic Curves. Symmetry 2020, 12, 1394 .
AMA StyleIoana Crăciun, Dorian Popa, Florina Serdean, Lucian Tudose. On Approximate Aesthetic Curves. Symmetry. 2020; 12 (9):1394.
Chicago/Turabian StyleIoana Crăciun; Dorian Popa; Florina Serdean; Lucian Tudose. 2020. "On Approximate Aesthetic Curves." Symmetry 12, no. 9: 1394.
An important aspect that must be considered when designing micro-electro-mechanical systems (MEMS) for all domains, including robotics, is the thermoelastic damping which occurs when the MEMS material is subjected to cyclic stress. This paper is focused on a model for the thermoelastic damping developed based on the generalized thermoelastic theory with the non-Fourier thermal conduction equation. The model was implemented in MATLAB and several simulations were performed. The theoretical results show a decrease in the deflection amplitude with the increase in time. The deflection amplitude decrease was validated by the experimental investigations, consisting of measuring the loss in amplitude and velocity of oscillations as a function of time. Moreover, this paper also presents the influence of the geometric dimensions on the mentioned decrease, as well as on the initial and final values of the amplitude for several polysilicon resonators investigated in this paper.
Florina Serdean; Marius Pustan; Cristian Dudescu; Corina Birleanu; Mihai Serdean. Analysis of the Thermoelastic Damping Effect in Electrostatically Actuated MEMS Resonators. Mathematics 2020, 8, 1124 .
AMA StyleFlorina Serdean, Marius Pustan, Cristian Dudescu, Corina Birleanu, Mihai Serdean. Analysis of the Thermoelastic Damping Effect in Electrostatically Actuated MEMS Resonators. Mathematics. 2020; 8 (7):1124.
Chicago/Turabian StyleFlorina Serdean; Marius Pustan; Cristian Dudescu; Corina Birleanu; Mihai Serdean. 2020. "Analysis of the Thermoelastic Damping Effect in Electrostatically Actuated MEMS Resonators." Mathematics 8, no. 7: 1124.
Automotive industry is constantly developing due to the use of new technologies and materials that are allowing the finding of novel solutions in order to solve existing problems. This study is focused on using a mathematical predictor called Kriging for the tribological properties of iron-based composites so as to estimate their values. First, experimental data regarding the tribological properties was obtained for four Fe-Cu-graphite-Ni-TiO2 composite materials. Based on this data the appropriate Kriging estimator is established and the values for the friction coefficient and wear rate are predicted at intermediary TiO2 contents. Therefore, without using expensive equipment and time-consuming experimental tests such as trial and error method, the tribological properties of iron-based composite materials can be estimated. Based on the predicted values and using an optimization algorithm, the material with the optimal tribological behavior can be determined in order to be used in applications for the automotive industry, such as the manufacturing of brake pads.
Florina Maria Șerdean; Violeta Valentina Merie; Corina Julieta Bîrleanu; Cătălin Ovidiu Popa; Marius Sorin Pustan. Estimation of Tribological Properties for Fe-Cu-Graphite-Ni-TiO2 Composites for Automotive Industry. Proceedings of the 4th International Congress of Automotive and Transport Engineering (AMMA 2018) 2018, 421 -428.
AMA StyleFlorina Maria Șerdean, Violeta Valentina Merie, Corina Julieta Bîrleanu, Cătălin Ovidiu Popa, Marius Sorin Pustan. Estimation of Tribological Properties for Fe-Cu-Graphite-Ni-TiO2 Composites for Automotive Industry. Proceedings of the 4th International Congress of Automotive and Transport Engineering (AMMA 2018). 2018; ():421-428.
Chicago/Turabian StyleFlorina Maria Șerdean; Violeta Valentina Merie; Corina Julieta Bîrleanu; Cătălin Ovidiu Popa; Marius Sorin Pustan. 2018. "Estimation of Tribological Properties for Fe-Cu-Graphite-Ni-TiO2 Composites for Automotive Industry." Proceedings of the 4th International Congress of Automotive and Transport Engineering (AMMA 2018) , no. : 421-428.
The reliability design and the lifetime of MEMS from optical applications is strongly dependent on the operating conditions. In optical devices an additional stress is introduced by the temperature gradient appearing during operation. The thermal stress introduced in the structure modifies the component response and its lifetime. The investigated sample is a micromirror fabricated from gold using the MEMS technologies and tested by an atomic force microscope. The scope is to analyse the temperature and relative humidity influence on the mechanical and tribological behaviours. Using a mechanical force given by the bending deflection and stiffness of the AFM probe, the dependence between the applied force and the micromirror deformation is monitored as a function of temperature. By increasing the temperature of structures the stiffness decreases based on the thermal relaxation of the material. If the relative humidity increases the adhesion between the micromirror and substrate is improved based on the capillarity effect. The results obtained are useful to MEMS designers who can predict the micromirror response as a function of the operating conditions with influence on the actuation energy, the accuracy in response and the system lifetime.
Marius Pustan; Corina Birleanu; Florina Serdean. Impact of environmental conditions on the reliability of MEMS components from optical applications. MATEC Web of Conferences 2017, 137, 07006 .
AMA StyleMarius Pustan, Corina Birleanu, Florina Serdean. Impact of environmental conditions on the reliability of MEMS components from optical applications. MATEC Web of Conferences. 2017; 137 ():07006.
Chicago/Turabian StyleMarius Pustan; Corina Birleanu; Florina Serdean. 2017. "Impact of environmental conditions on the reliability of MEMS components from optical applications." MATEC Web of Conferences 137, no. : 07006.
In this paper, the adhesion behaviors of SU-8 polymer thin film from MEMS application were investigated as a function of relative humidity. The adhesion test between the AFM tip and SU-8 polymer have been extensively studied using the atomic force microscope (AFM), for a relative humidity (RH) varying between 20 and 90%. The samples for tests are SU-8 polymers hard baked at different temperatures. The hard bake temperature changes the tribo-mechanical properties of polymers. The paper reports the measurements and the modeling of adhesion forces versus humidity in controlled ranges between 20 to 90%RH. To investigate the effect of relative humidity on adhesion for SU-8 polymer hard baked we used an analytical method which encompasses the effect of capillarity as well as the solid-to-solid interaction. While the capillary force expression is considered to be the sum of the superficial tension and the Laplace force for the solid-solid interaction is expressed by the Derjagin, Muller and Toropov (DMT) model of solids adhesion. The analytical results obtained are in accordance with those obtained experimentally.
Corina Birleanu; Marius Pustan; Rodica Voicu; Florina Serdean; Violeta Merie. Humidity influence on the adhesion of SU-8 polymer from MEMS applications. MATEC Web of Conferences 2017, 137, 8002 .
AMA StyleCorina Birleanu, Marius Pustan, Rodica Voicu, Florina Serdean, Violeta Merie. Humidity influence on the adhesion of SU-8 polymer from MEMS applications. MATEC Web of Conferences. 2017; 137 ():8002.
Chicago/Turabian StyleCorina Birleanu; Marius Pustan; Rodica Voicu; Florina Serdean; Violeta Merie. 2017. "Humidity influence on the adhesion of SU-8 polymer from MEMS applications." MATEC Web of Conferences 137, no. : 8002.
This study presents a methodology for an optimal design under uncertainty of a real bearing arrangement. The aim is to find the optimal bench bearing arrangement preload/clearance that maximizes the life of the bearing arrangement considering several uncertain geometric and operating parameters. The paper also presents a new systemic method used to determine the bearing loads required for the life calculations of the bearing arrangements. This method is suitable to be used within an Evolutionary Algorithm due to the fact that it is fast and reliable. The optimal design of the considered bearing arrangement—from the maximum bearing life standpoint—is achieved using a new and efficient stochastic optimization tool obtained by combining the features of Cuckoo Search algorithm and the ones of the Knowledge Gradient policy. Also, a specific approach for optimization under uncertainty using three stages is proposed in this paper. The obtained results are validated by Monte Carlo Sampling.
Lucian Tudose; Florina Rusu; Cristina Tudose. Optimal design under uncertainty of bearing arrangements. Mechanism and Machine Theory 2016, 98, 164 -179.
AMA StyleLucian Tudose, Florina Rusu, Cristina Tudose. Optimal design under uncertainty of bearing arrangements. Mechanism and Machine Theory. 2016; 98 ():164-179.
Chicago/Turabian StyleLucian Tudose; Florina Rusu; Cristina Tudose. 2016. "Optimal design under uncertainty of bearing arrangements." Mechanism and Machine Theory 98, no. : 164-179.