bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient and sustainable hydrogenation of levulinic-acid to gamma-valerolactone in aqueous solution over acid-resistant CePO4/Co2P catalysts
Authors: Feng Hui-Juan , Li Xiao-Chen , Qian Hao , Zhang Ya-Fang , Zhang Di-Hui , Zhao Dan , Hong San-Guo , Zhang Ning
Published: February 2019

Following an accelerated L–H process, efficient and sustainable hydrogenation of LA with 97% yield of GVL at TOF of 0.27–0.61 s−1 in water was achieved on low-cost and acid-resistant CePO4/Co2P composite.
Optical interference-based sensors for the visual detection of nano-scale objects
Authors: Frosiniuk Anna , Kolchanov Denis S. , Milichko Valentin A. , Vinogradov Alexandr V. , Vinogradov Vladimir V.
Published: February 2019

In this study, we present a new concept for the simple visual detection of nano-scale objects in solutions.
Alignment of semiconducting graphene nanoribbons on vicinal Ge(001)
Authors: Jacobberger Robert M. , Murray Ellen A. , Fortin-Deschênes Matthieu , Göltl Florian , Behn Wyatt A. , Krebs Zachary J. , Levesque Pierre L. , Savage Donald E. , Smoot Charles , Lagally Max G. , Desjardins Patrick , Martel Richard , Brar Victor , Moutanabbir Oussama , Mavrikakis Manos , Arnold Michael S.
Published: February 2019

Aligned semiconducting armchair graphene nanoribbons with excellent charge transport properties are synthesized on vicinal Ge(001) substrates via chemical vapor deposition.
Cinnamic acid derivatives as promising building blocks for advanced polymers: synthesis, properties and applications
Authors: Fonseca Ana C. , Lima Mafalda S. , Sousa Andreia F. , Silvestre Armando J. , Coelho Jorge F. J. , Serra Arménio C.
Published: February 2019

A global overview of the use of cinnamic acid derivatives in polymer science is given in this review paper.
Quantification of the hydrophobic effect using water-soluble super aryl-extended calix[4]pyrroles
Authors: Escobar Luis , Ballester Pablo
Published: February 2019

We report the quantification of the hydrophobic effect using a model system based on water-soluble super aryl-extended calix[4]pyrrole receptors and a series of pyridylN-oxide derivatives, bearing a non-polarpara-substituent, as guests.
Synthesis of aryl and heteroaryl tetrafluoro-λ6-sulfanyl chlorides from diaryl disulfides using trichloroisocyanuric acid and potassium fluoride
Authors: Saidalimu Ibrayim , Liang Yumeng , Niina Kiyoteru , Tanagawa Kazuhiro , Saito Norimichi , Shibata Norio
Published: February 2019

A catalyst-free method for the synthesis of (Het)ArSF4Cl by using trichloroisocyanuric acid and potassium fluoride in acetonitrile is disclosed.
A sulfonated triazine-based covalent organic polymer supported on a mesoporous material: a new and robust material for the production of 5-hydroxymethylfurfural
Authors: Babaei Zahra , Chermahini Alireza Najafi , Dinari Mohammad , Saraji Mohammad , Shahvar Ali
Published: February 2019

Herein, a triazine based covalent organic polymer was grown on mesoporous SBA-15 through the condensation of melamine and cyanuric chloride, and was used as a catalyst for the production of HMF.
Less active CeO2regulating bifunctional oxygen electrocatalytic activity of Co3O4@N-doped carbon for Zn–air batteries
Authors: He Xiaobo , Yi Xuerui , Yin Fengxiang , Chen Biaohua , Li Guoru , Yin Huaqiang
Published: February 2019

Less active CeO2is introduced to boost the bifunctional oxygen electrocatalytic activity of Co3O4@N-doped carbon.
Structural impact of Zn-insertion into monoclinic V2(PO4)3: implications for Zn-ion batteries
Authors: Park Min Je , Yaghoobnejad Asl Hooman , Therese Soosairaj , Manthiram Arumugam
Published: February 2019

Detailed structural analysis reveals that Zn-insertion into V2(PO4)3 induces heavy distortion due to strong host–guest interactions.
Achieving gradient-pore-oriented graphite felt for vanadium redox flow batteries: meeting improved electrochemical activity and enhanced mass transport from nano- to micro-scale
Authors: Wang Rui , Li Yinshi , He Ya-Ling
Published: February 2019

A gradient-pore-oriented graphite felt electrode was prepared by a facile one-step etching method, showing improved electrochemical activity and enhanced mass transport from nano- to micro-scale in flow batteries.
Wearable high-dielectric-constant polymers with core–shell liquid metal inclusions for biomechanical energy harvesting and a self-powered user interface
Authors: Gao Shengjie , Wang Ruoxing , Ma Chenxiang , Chen Zihao , Wang Yixiu , Wu Min , Tang Zhiyuan , Bao Ning , Ding Dong , Wu Wenxuan , Fan Fengru , Wu Wenzhuo
Published: February 2019

Deformable energy devices capable of efficiently scavenging ubiquitous mechanical signals enable the realization of self-powered wearable electronic systems for emerging human-integrated technologies.
Perovskite solar cells employing an eco-friendly and low-cost inorganic hole transport layer for enhanced photovoltaic performance and operational stability
Authors: Li Xin , Yang Junyou , Jiang Qinghui , Lai Hui , Li Shuiping , Tan Yao , Chen Ying , Li Suwei
Published: February 2019

A novel and eco-friendly MnS is employed as an inorganic HTL in a perovskite device with high PCE of ∼20%.
Single-crystal N-doped SiC nanochannel array photoanode for efficient photoelectrochemical water splitting
Authors: Chen Shanliang , Zhao Lianfu , Wang Lin , Gao Fengmei , Yang Weiyou
Published: February 2019

We investigated the photoelectrochemical water splitting of N-doped 4H-SiC nanochannel array photoanode with high photocurrent density and fast photoresponse.
Metal particle movement and distribution characteristics under AC voltage and ball‐plane electrodes
Authors: Sun Jixing , Sun Lei , Chen Weijiang , Li Zhibing , Yan Xianglian , Xu Yuan
Published: February 2019

Metal particles, difficult to be eliminated in gas‐insulated metal‐enclosed switchgear (GIS), can cause GIS discharge and breakdown between electrodes, or flashover on the insulator surface. It influences the development of ultra‐high voltage (UHV) projects. Therefore, the work optimised the model of metal particle movement under AC voltage, studying the metal particle movement and distribution characteristics between ball‐plane electrodes through experiment and simulation. Under AC voltage, the particle jumps on a small scale on the plane surface. With the increase of voltage, the jump amplitude increases. However, the collision frequency decreases until the particle collides with the ball electrode. When the initial phase angle of power changes, the particle‐moving pattern is symmetrical in the angle ranging from 0 to 180°, and from 180 to 360°. The collision frequency changes slightly with the increase of jump amplitude when the angel ranges from 0 to 120°.
Miniature tri‐wideband Sierpinski–Minkowski fractals metamaterial perfect absorber
Authors: Amiri Majid , Tofigh Farzad , Shariati Negin , Lipman Justin , Abolhasan Mehran
Published: February 2019

With rapidly growing adoption of wireless technologies, requirements for the design of a miniature wideband multi‐resonators are increasing. In this study, a compact fractal‐based metamaterial structure with lumped resistors is described. The structure of the authors proposed absorber is a combination of Sierpinski curve and Minkowski fractal. The new combination provides larger capacitance and inductance in the system enabling perfect absorption at lower frequencies. The final structure with dimensions of 20 × 20 × 1.6 mm3 and an air gap of 12.5 mm provides three main resonances at frequencies of 2.1, 5.1, and 12.8 GHz with bandwidth (absorption ratio over 90%) of 840 MHz, 1.05 GHz, and 910 MHz, respectively.
Single‐stage impedance source inverters with quasi‐DC–DC output cell for working in dual inductor current modes
Authors: Liu Hongchen , Ji Yuliang , Yong Feng , Wu Fengjiang , Wheeler Pat
Published: February 2019

Single‐stage impedance source inverters with quasi‐DC–DC output cell (QDDOC) are proposed here. The QDDOC is derived from DC–DC converters, and QDDOC can be applied in all the existing impedance source inverters. Compared to the traditional impedance source inverters without QDDOC, the proposed inverters with QDDOC can adapt to the wider inductor parameter range and flexibly work into dual inductor current states: continuous conduction mode (CCM) and discontinuous conduction mode (DCM). Also, the proposed inverters can retain the single‐stage voltage‐boost performance, and solve the DC‐link voltage drop produced by DCM. Under DCM, the proposed inverters improve the boost ability, lower the inductor values, size and weight, and reduce the voltage stresses across passive components. The circuit topologies, modulation strategies, and operating principles are analysed in detail. Finally, experiment results verify the validity of proposed topologies.
Efficient modelling of SAR texture with a gamma‐inverse gamma distribution for MAP‐based speckle suppression
Authors: Ku Mahapatra Dheeren , Roy Lakshi Prosad
Published: February 2019

The precise statistical modelling of synthetic aperture radar (SAR) texture is crucial while formulating maximum a posteriori (MAP) filter for speckle suppression. In this study, the authors introduce an SAR texture model considering the mixture of gamma and inverse gamma distribution as an approximation to a generalised inverse Gaussian (GIG) distribution, which suitably portrays areas with a varying degree of heterogeneity. An estimator is proposed for the model parameters using the expectation–maximisation (EM) algorithm. Cramer‐Rao bounds are also derived for the model parameters to evaluate the effectiveness of the EM estimator. Furthermore, the model is experimentally established as an approximation to the GIG distribution through Monte Carlo simulation. Suitability and applicability of the model is then validated through 1‐look real clutter and multilook synthetic clutter data over textured areas. Utilising the above model as prior density, the authors proposed an MAP filter for speckle suppression in SAR clutter data from areas of a diverse kind. Finally, the effectiveness of the ‐MAP filter is assessed using different statistical measures and is found superior over the MMSE‐based Lee, Kuan filters and MAP‐based ‐MAP, ‐MAP, ‐MAP, CE‐MAP filters in terms of speckle suppression and mean preservation.
Integrated energy efficient cooling solutions for large prefabricated panels collective dwellings from the 1970s
Authors: Adam Marius , Muntean Daniel M. , Popov Miodrag , Grecea Daniel , Ungureanu Viorel
Published: February 2019

The intense urbanization process Romania has known during the industrialization period of the 1960-70s led to an exponential shortage in urban housing. Similar to other countries, but more specifically to the former Eastern block, Romanian state-financed collective dwellings were erected starting from standardized projects of Reinforced Concrete Large Prefabricated Panels (RCLPP) blocks of flats, generating nowadays a particular built stock of identical buildings and several apartment types, widespread throughout the entire country. These buildings currently house 60% of the urban population of Romania that own 96% of the apartments, as opposed to the European trends regarding the number of owner-occupied barely reaching 60%. Even though at not even half of their intended lifespan, the collective dwellings do not satisfy basic comfort conditions such as cooling and ventilation, being in an urge of retrofitting and upgrading. Individually applicable cooling systems undertaken by the owners have proved to be acceptable, but did not, however, contribute to a decrease in the overall energy consumption of the buildings. The present paper analyses the individual cooling systems being currently applied in Romanian apartments as opposed to a global-holistic system on block level, in terms of energy consumption and efficiency, flexibility of owner controlled indoor microclimate. The results show the potential of introducing renewable energy sources as viable alternatives for the existing systems.
An overview of the microclimate conditions inside healing chambers
Authors: Dumitrescu Ionel Lucian , Ghiaus Adrian-Gabriel
Published: February 2019

In the civil and industrial construction engineering, the comfort of occupants is ensured by achieving appropriate microclimate conditions. The human physical comfort (thermal, visual, acoustic) is achieved when the person from an enclosure is in a state of equilibrium and is able to perform tasks with maximum possible efficiency and without any kind of stress. Similarly, in the case of crops grown inside protected spaces, for plants, just as in the case of human being, specific microclimate conditions need to be ensured for their optimum development during the vegetation period. Plant development is a result of its own genetic features, but this is influenced by microclimate conditions inside of the greenhouses. Even more, in the case of healing and acclimatization rooms for grafted vegetables, the specific microclimate conditions must be strictly monitored. Technologically, it is recommended an optimum indoor temperature between 23°C and 25°C, with a maximum value that must not exceed 28°C, under conditions of relative humidity around 85% - 95%. Other two important aspects are the CO2 concentration and the level of solar radiation. The value of the CO2 concentration is an indicator of the healing process. For the grafting process, it is useful to know the time of the connection of the donor and receiver. Led by the the light levels, the photosynthetic activity of the grafted seedlings in the healing period, lead to a decreasing of CO2 concentration. This means that the two parts of the planting material are jointed, healed. So, the farmers can manipulate the environment in the healing rooms. This paper presents an overview of the scientific and technical issues that have to be achieved in order to reach suitable control and management of microclimate conditions in healing rooms for grafted vegetables.
Evaluation of mean velocity and mean speed for test ventilated room from RANS and LES CFD modeling
Authors: Ivanov Nikolay , Zasimova Marina , Smirnov Evgueni , Markov Detelin
Published: February 2019

The paper presents and discusses data for the ventilation airflow in an isothermal room corresponding to the Nielsen et al. (1978) test computed with Large Eddy Simulation (LES) and Reynolds-Averaged Navier-Stokes (RANS) approaches. As LES computations provide directly both the speed and velocity components data, the difference between the mean speed and mean velocity values is computed and discussed. For the RANS computations that give the mean velocity data only, application of the velocity-to-speed conversion procedure based on the turbulence kinetic energy field provided by a turbulence model resulted in accurate mean speed evaluation.
Numerical simulation of the flow into a circular pipe section
Authors: Muscă Gelu , Chitaru George Mădălin , Coşoiu Costin Ioan , Nae Cătalin
Published: February 2019

Computational Fluid dynamics (CFD) is the science that evolves rapidly in numerical solving of fluid motion equations to produce quantitative results and analyses of phenomena encountered in the fluid flow. When properly used, CFD is often ideal for parameterization studies or physical significance investigations of flow that would otherwise be impossible to replicate through theoretical or experimental tests. The aim of this paper is the study of the turbulent airflow and how the vortices formed in turbulent airflow are influenced by the evolution of the hydraulic characteristics of the fluid flow. Unsteady numerical simulation were performed using Reynolds Average Navier-Stokes (RANS) turbulence model adapted to conventional flow into a pipe with variable section which was implemented in the ANSYS FLUENT expert software.
Predictions on the dynamic behaviour of an aeroelastic model of a television tower in the boundary layer wind tunnel
Authors: Chiulan Elena-Alexandra , Coşoiu Costin Ioan , Georgescu Andrei-Mugur , Anton Anton , Degeratu Mircea
Published: February 2019

This paper presents the process of making a set of vibration measurements on a model of a television tower in the boundary layer wind tunnel. The main objective of the study is to predict the dynamic behaviour of the full-scale structure under the turbulent wind action, specific for the Bucharest site, in Romania. Wind tunnel tests were performed on a 1:500 scale aeroelastic model, existing at the Aerodynamics and Wind Engineering Laboratory “Constantin Iamandi” from the Technical University of Civil Engineering Bucharest. As a result of the vibration measurements on the tower's model, the dynamic behaviour of the structure on the real scale could be determined by using the conditions and relationships of similitude established between the two, model and prototype (full-scale structure). The experimental analysis made in this study may be very important not only in assessing the dynamic response for a building of such importance, during the preliminary stages, but also can be very helpful for the decision makers involved in the design process to choose which is the best solution for such high and slender structures under the action of turbulent wind.
Solar protection influence on dynamic insulation efficiency of double skin façades
Authors: Cherecheş Nelu-Cristian , Popovici Cătălin George , Cîrlan Vasile Valerică , Hudişteanu Sebastian Valeriu
Published: February 2019

The objective of the study was to perform a numerical analysis in order to determine the best position for placing sunscreen inside the channel of a double skin façade insulation relative to dynamic insulation efficiency, using ANSYS-Fluent software. The analysis was performed for summer conditions in forced convection for two airspeed regimes inside the channel: 0.2m/s and respectively 0.5m/s. Regime is considered permanent and the only parameter changed is the position of the blinds in the channel. Results are shown by spectra and profiles of temperature and velocity in order to analyse thermodynamic behaviour of a double skin façade. The numerical results emphasize that effectiveness of sunscreen such as blinds, is proportional to the flow velocity inside the channel and inversely proportional to the distance from the outer glazing. Ranked as the most effective sun protection is when it is located at the outer glazing and air velocity at the entrance is 0.5m/s.
Development of an indoor testing rig for façade integrated solar thermal collectors
Authors: Moldovan Macedon , Vişa Ion
Published: February 2019

New solar thermal collectors with triangular and trapezoidal shapes and different colours (red, blue, green etc.) were developed in the Renewable Energy Systems and Recycling Research Centre, R&D Institute of the Transilvania University of Brasov, Romania to increase their architectural acceptance when integrated in buildings façades. An indoor testing rig was developed to assess: a) the performance of the new solar thermal collectors vertically installed on the façade, b) the influence of the façade integrated solar thermal collectors on the building envelope and thus on the indoor thermal comfort, c) the influence of the building envelope on the solar thermal collectors efficiency. The design process of the indoor testing rig is presented in the paper along with numerical simulations and experimental results.
Study of fragile capillary-porous coatings in power installations
Authors: Genbach Alexander , Jamankulova Nellya , Iliev Iliya , Terziev Angel
Published: February 2019

For carrying out the high-technological processes in heat power installations the fragile capillary-porous coatings up to a limiting condition of heat exchange surface were researched. The coatings made of metallic materials (copper and stainless steel) and of natural mineral media (quartz, granite and teschenit) were studied. A model of the nucleation of steam bubbles in the cells of the porous coatings was developed during vaporization of coolant from their explosive emergence, taking into account the development of the “dry” spots before the damage; also the dynamic angle was defined in the range of (74÷80) degrees. The limiting state of the medium according to the model of the bubbles is studied when solving the problem of thermal elasticity. During the destruction of the coating caused by only a compression a number of curves corresponding to a definite thickness of the coming-off coating particle were obtained. Intervals of the specific heat fluxes coming to steam bubbles are established. In these intervals there is a destruction of a porous coating and metal surfaces at the joint action of capillary and gravity potentials.
Impinging jets array: an experimental investigation and numerical modeling
Authors: Dhondoo Nilesh , Simionescu Ştefan-Mugur , Bălan Corneliu
Published: February 2019

This paper reports on the measurements of wall shear stress and static pressure along a smooth static wall upon which jet impingement occurs. The effect of a single circular jet, respectively an array of jets is studied using a high speed/resolution camera. The areas of interest are the stagnation region and the wall jet region, where the jet is deflected from axial to radial direction. The effect of increasing the distance between the inlets is also investigated. The results are obtained by performing direct flow experimental visualizations and CFD numerical simulations, using the Reynolds averaged Navier-Stokes (RANS) approach with the commercial software ANSYS Fluent. The findings suggest that the smaller the nozzle-to-wall distance is, the higher the pressure peak. The wall shear stress has a bimodal distribution; at stagnation point, the wall shear stress is 0. An increase in the number of inlets produces the effect of a decrease in the stagnation point pressure. The greater the inter-inlet distance is, the greater the stagnation point pressure (there is less inter-jet mixing, less energy is lost in vortices formed between jets).
Joint energy and water management scheme for water supply systems in Romania
Authors: Delcea Aida , Bitir-Istrate Ioan , Pătraşcu Roxana , Gheorghiu Cristian
Published: February 2019

Keeping in mind the short-term and long-term aims of cost depletion and sustainable development respectively, a joint water and energy management scheme for water supply systems that leads to reduced energy losses is proposed. For water utilities, drinkable water's treatment and pumping and wastewater treatment are the main energy-consuming processes and a proportional part of this energy is wasted with non-revenue water. In Romania, these losses can reach critical levels so highlighting them becomes a crucial aspect in assessing the system's efficiency. This paper presents a scheme that combines energy audit and water balance techniques that can become a tool for both energy auditors and managers, by allowing the quantification of embedded energy of water losses. The methodology is adapted for the conditions in Romania, where data collection and processing is mainly done manually.
Analysis of hydropower ratio from total energy production in Romania
Authors: Neagoe Angela , Tică Eliza Isabela , Diminescu Mihaela Amalia , Popa Bogdan , Cismaş Suzana Carmen
Published: February 2019

It is important to know the structure of electricity production of a country and to establish the place of each source within the total energy mix. The aim of this paper is to analyze statistically the percentage of the hydropower production related to the total electrical energy produced in Romania. The time series data analysis was done to determine the trends of average and standard deviation of hydro energy data produced in Romania over eleven years' period (2006-2016).
Experimental methods to determine the hydraulic conductivity
Authors: Diminescu Mihaela-Amalia , Dumitran Gabriela-Elena , Vuţă Liana-Ioana
Published: February 2019

Hydraulic conductivity is one of the most variable and yet an essential parameter in environmental engineering, in estimation of contaminant travel time in soils and groundwater. Also, it is one of the most difficult parameters to determine, and directly affects the quantity of water that will flow. Hydraulic methods for estimation the hydraulic conductivity can be either laboratory methods or in-situ methods. This study presents five laboratory methods which can be used to estimate the hydraulic conductivity of soils: variable-head permeameter - Kamenski; simplified permeameter; constant-head Cromer permeameter, in two working configurations; constant-head permeameter connected to piezometric tubes and a variable-head permeameter. Although these methods require more labour than other available methods, e.g. the correlation methods, they are relatively fast and not expensive. For the porous material used in the experiments, the most accurate values of the hydraulic conductivities were obtained with the constant-head permeameter connected to piezometric tubes.
The water footprint from hydroelectricity: a case study for a hydropower plant in Romania
Authors: Robescu Lăcrămioara Diana , Bondrea Dana Andreya
Published: February 2019

In Romania, the hydropower is the main form of renewable source with an important share in energy mix. Despite their valuable advantages on supplying energy and balancing the energy system, public acceptance, environmental, social and economic impact has become a common challenge in development of hydropower projects. Increasing of water consumption and raising awareness regarding available water resources leads to an integrated management approach of them. In this paper the water footprint is estimated for one of the largest Romanian hydropower project, namely Hydropower Plant Vidraru. The water footprint from hydroelectricity is evaluated considering electricity production of the hydropower plant, water footprint of dam construction and three different approaches to quantify water footprint of the reservoir: gross water consumption, net water consumption and water balance. Also, water footprint is assessed based on economic value of the reservoir using allocation coefficients for various purposes of the reservoir. It is estimated that economic benefit of the reservoir is 81.92·106 €/y, with hydroelectricity major contributor.
Influence of reservoir shape upon the choice of Hydraulic vs. Hydrologic reservoir routing method
Authors: Ionescu Cristina Sorana , Gogoaşe Nistoran Daniela Elena
Published: February 2019

The objective of the paper is to compare the hydrologic and hydraulic reservoir routing methods in term of assumptions, equations, numerical computation procedures, necessary data and advantages-disadvantages of their use. To test the results provided by the two methods, a set of two reservoirs from Romania was chosen: one long and narrow and the other one roundly shaped. Corresponding inflow hydrographs were chosen, and similar conditions were imposed for the outflow dam control structures, namely the initial water level in the reservoir to be at the Spillway Crest Level (SCL) and no outflow control. For the hydrologic method the Puls procedure was used and a program was written in Scilab to solve the continuity equation in finite differences. For the hydraulic method HEC-RAS software was used to solve the 1D Saint-Venant equations. Outflow and stage hydrographs at the dam were compared together with the stage hydrograph at the reservoir tail for the hydraulic method. Results show that the hydraulic method should be used for the long and narrow reservoirs, as it considers the backwater effect, whereas the hydrologic method can be efficiently used for all other reservoirs where this effect is negligible.
Pedestrian-level ventilation in an urban environment adjacent to a river channel: A case study for Bucharest city – Romania
Authors: Ciocănea Adrian , Dragomirescu Andrei , Tofan Bogdan , Toti Mihai
Published: February 2019

Increasing evapotranspiration in cities, derived from vegetation and water bodies, can effectively mitigate the effect of urban heat island (UHI). This paper presents a study on an urban ventilation solution for Bucharest City in Romania. The solution is based on lifting air volumes from the free surface of Dambovita River, which crosses the city center where UHI has a significant impact, to the roadway and pedestrian level by using cross-flow fans mounted on floating panels planted with vegetation, which are placed at the river banks. The electric motors of the cross-flow fans are powered by PV solar cells. The real optimal value of evapotranspiration (ETRO) was computed for the case of lucerne in order to assess the air temperature at the surface of the floating panel and a numerical study was performed in order to obtain the velocities of the air flow and the temperature field in a domain containing the free surface of the river, the floating panel surface, and the roadway surface (at pedestrian level). It was observed that, at low flow rates, the cooler air reaches the roadway surface in a compact jet due to the Coanda effect - the coherent air jet is of about 30–40 cm above the ground level. For a day with clear sky and no wind conditions a decrease in the air temperature of 4–5 °C can be obtained at the pedestrian level, within a layer of 1 m height. The study opens the possibility to approach such issues at a greater scale in order to assess the viability of appropriate solutions for cooling down the urban heat island as well.
Chronological reflection on monitoring urban areas subsidence due to groundwater extraction
Authors: Radutu Alina , Gogu Radu Constantin
Published: February 2019

Land subsidence affects urban areas worldwide. Sometimes it could be driven by intensive groundwater withdrawal to assure different urban needs and functionalities. Some of these urban areas have a long history of subsidence that covers almost a century. The aim of this paper is to present the evolution of several urban areas affected by land subsidence, the methods used to monitor vertical displacements along the decades in relationship to the groundwater extraction associated to the urban expansion, and the mitigation techniques used for countering the effects of intensive groundwater withdrawal. Even the originally applied subsidence monitoring methods (such as geometric levelling) are still very sensitive, in terms of time consuming, covered area, and financial effort, these methods might be complemented by new methods based on Synthetic Aperture Radar Interferometry (InSAR). InSAR methods show also a significant progress during the last decades when considering the subsidence sensed order of magnitude.
Methodology and calculation model for recycling of composite construction products
Authors: Vladimirov Victor , Bica Ioan
Published: February 2019

The circular economy development has increased awareness on how construction products are treated at the end-of-life stage (EoL). With a growing recognition of the finite nature of primary resources, manufacturing processes are being shifted from the traditional take-make-dispose approach to a greater holistic practice, where valuable and/or scarce substances are recovered at the end of a product’s life. Life Cycle Assessment (LCA) is gaining wider attractiveness, as assessment of environmental impacts constitutes an effective quantitative decision tool to identifying sustainable solutions. At the same time, existing guidelines, technical specifications and methods for LCA assessment at EoL are rather heterogeneous regarding modelling and calculation of related secondary material and energy streams. For construction products, category rules for Environmental Product Declarations (EPD) according to EN 15804 (issued through the European Committee for Standardization) and the Product Environmental Footprint (PEF) (developed by the European Commission) currently represent the most advanced methodological references. The study presents the methodological approach per EN 15804, describing the benefits and loads beyond the typical disposal stage. Thus, the environmental impacts of a construction element can be credited in accord to its material and energetic recycling potential. An applied model is realized for water pipes made of composite material. The calculation is exemplified and comparative results of allocation scenarios per EN 15804 and PEF are discussed, demonstrating correlations between the normative requirements and their application. The results support further identification, assessment and ranking of recycling alternatives (i.e. mechanical, thermal, chemical).
Experimental studies to determine the physico-mechanical characteristics of soils improved with special hydraulic binders
Authors: Andrieş Gabriela , Batali Loretta
Published: February 2019

The complexity of the construction works and site conditions, combined with environmental factors, led to the necessity of using special mineral binders with physical and chemical properties superior to the usual binders. Taking into account the above arguments, the paper presents the results of experimental laboratory studies in order to determine the physical and mechanical characteristics of soil used for a road embankment, after improvement with a special lime-based hydraulic binder. Since improvement recipes vary from one soil to another, it is important to always determine the characteristics after treatment. Also, the method of mixing the binder and soil decisively determines subsequent performance. As part of a larger study aiming at assessing the various factors of influence on the treated soil characteristics, two comparative studies were carried out, each consisting in the recipe formulation using 3 different binder ratios, the difference being given by the parameters used for specimen compaction: normal or modified Proctor test. The study followed the influence of the mechanical compaction work on the mechanical behaviour of the specimens over time after different times of curing.
Safety analysis of Novat tailings dam
Authors: Tatu Florian , Stematiu Dan
Published: February 2019

The Novat tailings dam is located in the upper basin of the Novat stream, which flows through the Ursul stream into the Vaser River. Mention should be made that the basins of the Vaser River and Viseu are protected areas, which do not allow any discharges downstream and require the repumping of the cleared waters back to the flotation of Baia Borsa mine. Overtopping of the main and downstream dams, with their partial destruction, occurred on 10 March 2000 as a result of the torrential rains falling across the entire surface of the Novat stream receiving basin. Before the accident occurred, deposits from the tailings dam reached 802.0 maSL, with the clear water mirror at 804.50 maSL. The paper deals with the safety of Novat tailings dam after the accident in March 2000.
North beltway of Cracow - selected elements of impact on the environment and the real estate market
Authors: Butryn Krzysztof , Jasińska Elżbieta , Kovalyshyn Oleksandra , Preweda Edward
Published: February 2019

The construction of such a large road facility as the city beltway can not have an impact on the environment. In addition to the obvious benefits to transport, attention should be paid to the environment of the area, in particular noise and air pollution. In December 2017, the Minister of Infrastructure and Construction signed the investment program for the implementation of the northern Krakow bypass road. General Directorate for National Roads and Motorways, the Kraków branch has announced an open tender for its implementation into the EU. Today, in our tender for the design and construction of the northern bypass road of Krakow, 8 offers was received. All tenderers give the date of completion of all works within 47 months. The length of the two-lane section of the beltway is about 12 km, each roadway will have 3 lanes. The POK (North Beltway od Cracow) will run mostly in the area of the Zielonki commune, through the towns of: Zielonki, Bibice, Węgrzce, Bosutów, Dziekanowice and Batowice. The analysis carried out show a very large increase in the value of real estates located in the northern part of Krakow and adjacent areas in recent years. According to the authors, the construction of the northern beltway and easier access to the center of Krakow through the modernization of the November 29 avenue will contribute to even greater interest in real estates located in this area. Real estate prices will certainly increase, rather only at the beginning of the investment. Residents will gain the comfort of an alternative transport line, but there will also be an increase in noise and air pollution, which is a particularly important problem in and around Krakow. The article presents the validation of these three issues in relation to changes in the real estate market in the commune of Zielonki.
The use of hierarchical cluster analysis for grouping atmospheric precipitation in Poland
Authors: Cupak Agnieszka , Ziernicka-Wojtaszek Agnieszka , Krużel Joanna , Jóźwiakowski Krzysztof , Wałęga Andrzej , Grzywna Antoni , Bochniak Andrzej , Obroślak Radomir , Mazur Andrzej , Serafin Artur
Published: February 2019

The aim of this study is to present the application of statistical methods to assess the possibility of grouping precipitation according to their elevation above sea level and precipitation levels in the temperate climate of Poland. The country was divided into regions with similar levels of precipitation using cluster analysis by Ward’s method. The study was performed with meteorological data on average monthly precipitation of 53 meteorological stations from 1981 to 2010. The selection of stations was dictated by the need to consider the variability in amounts of annual precipitation throughout the country. The data was used to calculate average annual precipitation total as well as average precipitation total in the summer half-year (from May to October) and the winter half-year (from November to April) for Poland, from 1981 to 2010. Statistical method was performed and six clusters were generated, for the elevation of the stations and average annual precipitation as well as average precipitation for hydrological half-years. The average annual precipitation for the clusters ranged from 530 mm (cluster 5) to 820 mm (cluster 2). The average precipitation for the winter hydrological half-year ranged from 190.1 mm (cluster 1) to 288.8 mm (cluster 5). The average precipitation for the summer hydrological half-year ranged from 326.3 mm (cluster 5) to 605 mm (cluster 2). The conclusions from the analysis carried out in the study are that: (1) grouping by means of Ward’s method can be used to distinguish homogeneous areas with the same levels of precipitation; (2) both precipitation and the elevation, at which meteorological stations are located, are the basis for distinguishing clusters in Ward’s method.
Brief review of operation of anaerobic wastewater treatment with membrane bioreactors
Authors: Mucha Zbigniew , Wójcik Włodzimierz , Polus Michał
Published: February 2019

In recent years, anaerobic membrane bioreactor (AnMBR) technology has been considered as a very appealing alternative for wastewater treatment due to its significant advantages over conventional anaerobic treatment and aerobic membrane bioreactor (MBR) technology. The paper provides an overview of the current status of the anaerobic membrane bioreactor technology with a special emphasis on its performance and drawbacks when applied for domestic and municipal wastewater treatment. According to the reported data, the renewable energy produced at the plants (i.e. from methane) covered the energy demand for membrane filtration while the excess energy can be further utilized. Anaerobic membrane bioreactors are an attractive technology that needs further research efforts and applications at an industrial scale.
Catchment management influence on the magnitude of the total solids load conveyed by the stormwater sewer system – a comparative case study
Authors: Górski Jarosław , Górska Katarzyna , Bąk Łukasz , Sałata Aleksandra
Published: February 2019

The aim of the investigations was to make a comparative analysis of TSS concentration and variability in TSS loads as well as to analyse first flush phenomena. That issue is related to the characteristics of two urban catchments located in the city of Kielce. The runoff events observed in the period of investigations (years 2009 – 2016) showed a great diversity. The analyses performed for the study revealed substantial differences in the values of TSS concentration and loads in stormwater from the catchments of concern. The highest TSS concentration in the stormwater for the catchment located at the city outskirts was 252 mg.dm-3, whereas for the catchment in the city centre that value was almost 30 – fold higher and amounted to 7432 mg.dm-3. The analysis of the runoff first flush with respect to the mass of total solids in individual rainfall events showed substantial differences in the course of the process depending on the type of catchment management. In the densely built-up area, the initial 25% and 30% of the volume of runoff transported 25-41% and 30-48% of the solids mass, respectively. In the other catchment, with low and sparsely located buildings, the maximum values of TSS mass were considerably higher and amounted to 22-83% and 28-87%.
Influence of the amount of inflowing wastewater on concentrations of pollutions contained in the wastewater in the Nowy Targ sewerage system
Authors: Nowobilska-Majewska Elwira , Bugajski Piotr
Published: February 2019

This study presents the results of the analysis concerning the influence of the amount of inflowing wastewater on concentrations of organic and biogenic pollutants, as well as chromium ions in wastewater flowing into the collective sewage treatment plant in Nowy Targ. The research was carried out in 2016 and 2017, where in the period of 24 months a total number of 87 wastewater samples were collected in order to determine the concentration of the analyzed pollution indicators. During this period, the average daily inflow of wastewater to the sewage treatment plant was also analyzed. Based on the analysis of linear correlation, it was stated that there is a high dependence of concentrations of organic and biogenic pollutants on the amount of inflowing raw wastewater. Furthermore, it was found that there is an average dependence of chromium ion concentrations in raw wastewater on the amount of inflowing wastewater. In order to minimize the high variability of the concentration of pollutants in raw wastewater, it is recommended to reconstruct the sewerage system from the combined sewer system to the distribution system. Additionally, it is recommended to monitor the sewerage network in order to eliminate illegal inflows of rainwater and industrial wastewater from furrier’s production facility.
Gate Driver Circuit Design, PWM signal generation using FEZ Panda III and Arduino for Inverter
Authors: D Srinivasa Rao , MN Sandhya Rani , Syed Sarfaraz Nawaz , Tummala Suresh Kumar
Published: February 2019

This paper presents the gate driver circuit design and PWM signal generation using FEZ panda III and Arduino boards for Inverter. FEZ panda III works on .net micro framework and all its programming, debugging features are available through Microsoft’s Visual studio whereas Arduino features are available through Arduino software. Inverters are used in various applications like in motor drives and solar and wind power applications. This paper is commenced by basic understanding of need of gate driver circuit for inverter and different types of PWM techniques for generating gate signals for inverter. Simulation of SPWM inverter in both open loop and closed loop operation is done and its respective gate voltage waveforms are studied and later hardware implementation of gate driver circuit using TLP250H IC is carried out and gate voltages at different duty cycles is studied with the help of FEZ Panda III and Arduino boards.
Application of Search Group Algorithm for Automatic Generation Control of Multi-area Multi-source Power Systems
Authors: Khamari Dillip , Sahu Rabindra Kumar , Panda Sidhartha
Published: February 2019

This paper proposes a new Search Group Algorithm based PID controller, to deal with Automatic Generation Control of two-area with six unit power system. The supremacy of SGA tuned PID controller is being shown using the comparative study with Firefly Algorithm (FA) optimization method for the same test system using ITAE as an objective function. It has been demonstrated that SGA tuned PID controller improves the performance in a large compared with FA tuned PID controller. Furthermore variation in nominal values of operating load condition and system parameters with the position of step load perturbation is being carried out to achieve sensitivity analysis. From the result of sensitivity analysis it clearly depicts the robustness of the suggested method (SGA with PID controller) for two-area with six unit power system in AGC. Finally for better investigation, the proposed method is also examined by applying randomization in step load.
Implementation of OCPP Protocol for Electric Vehicle Applications
Authors: Venkata Pruthvi Thota , Dutta Niladri , Bobba Phaneendra Babu , Vasudeva B Sai
Published: February 2019

The ability of the software and hardware systems to interchange information is a key factor for the success of the electric vehicle industry. Standards have been developed and are in use to ensure base level interoperability of the front-end communication and signaling processes for smart charging between electric vehicles and charge stations. The Open Charge Alliance (OCA), a group of European industries, have developed an open source common back-end protocol, called Open Charge Point Protocol (OCPP), for charging stations to reduce and secure overall investment costs. OCPP intends to enable grid services based on smart charging. In this paper the authors provide a review of the functionalities OCPP offers and how it can be used in the electrical vehicle-charging infrastructure.
A Hybrid Cascaded Multilevel Converter for Battery Vitality Administration Connected In Electric Transport for Battery Energy Management
Authors: Gadde Srinivas , Lukka Bhanu Ganesh , Gali Shankar Mahesh Kumar
Published: February 2019

In the (EV) electrical vehicles energy storage system plays a crucial role. Normally, in electrical vehicles large number of cells connected in series to increase the output voltage for driving motor. Battery cells will have different electrochemical characteristics which cause the difference in terminal voltage (or) (SOC) state of charge imbalances between the each cell. In this paper cascaded multilevel converter which involves in both management of energy and motor drives proposed for electric vehicles and each battery cell can be controlled to the circuit or bypassed by a half-bridge converter. All these half-bridges are cascaded to the output staircase shape dc voltage. And H-bridge converter will be used to change the direction of dc bus voltage to convert it ac voltage. The advantage of the converter will have multilevel voltages with small dv/dt and lesser harmonics. So, it is helpful to make better performance of motor drives. Through separate control according to state of charge of each cell the energy utilization of batteries can be improved drastically. By using the fuzzy logic controller for current measurement the THD can be reduced drastically. In order to verify the performance of proposed converter simulation done in matlab.
Compact edge and end coupled wide band filter with notch at 5GHz
Authors: Chenna Raasi , Doddi Vijayadithya , Gurram Sumanth , Sharma Vinay , Madhur Deo Upadhayay
Published: February 2019

In this paper a compact Ultra Wide Band filter with notch at WLAN frequency is designed. The filter is a designed using coupled lines arranged in inter digital capacitor form. The filter is designed to allow microwave signals in the range of 2GHz to 7GHz with a notch at 5GHz. The measured results show the notch at 5GHz with transmission coefficient of -14dB. With uniform group delay in pass band and nonlinear group delay at notch frequency.