bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on The Removal of Scale Ions from Circulating Cooling Wastewater by Chemical Coagulation Process
Authors: Du Song , Jin Wenbiao , Duan Feng
Published: June 2018

In this paper, the circulating cooling wastewater was treated by chemical coagulation process through adding NaOH/Na2CO3.The effect of NaOH and Na2CO3 dose on removal of scale ions, such as Ca2+, Mg2+, Ba2+, Sr2+, SiO2, was studied and the removal mechanism was discussed. The results showed that the increase of NaOH dose was beneficial to the removal of above-mentioned scale ions. When NaOH was only added, the removal efficiency of Ca2+, Mg2+, Ba2+, Sr2+, SiO2 was 86.3%, 91.6%, 86.5%, 58.1%, 84.2%, respectively. When 680 mg/L of NaOH and 300 mg/L of Na2CO3 were added, and the effluent pH was above 11.2, the removal efficiency of Ca2+, Mg2+ was 95.8% and 89.4%, respectively, and the concentration of Ca2+and Mg2+ was below 20 mg/L, which met the target of wastewater treatment. Finally the possible removal mechanism of Ca2+, Mg2+, Ba2+, Sr2+and SiO2 was discussed.
Mechanism study and numerical simulation of Uranium nitriding induced by high energy laser
Authors: Zhu Yuan , Xu Jingjing , Qi Yanwen , Li Shengpeng , Zhao Hui
Published: June 2018

The gradients of interfacial tension induced by local heating led to Marangoni convection, which had a significant effect on surface formation and the process of mass transport in the laser nitriding of uranium. An experimental observation of the underlying processes was very difficult. In present study, the Marangoni convection was considered and the computational fluid dynamic (CFD) analysis technique of FLUENT program was performed to determine the physical processes such as heat transfer and mass transport. The progress of gas-liquid falling film desorption was presented by combining phase-change model with fluid volume function (VOF) model. The time-dependent distribution of the temperature had been derived. Moreover, the concentration and distribution of nitrogen across the laser spot are calculated. The simulation results matched with the experimental data. The numerical resolution method provided a better approach to know the physical processes and dependencies of the coating formation.
Application Research on Stabilizing Treatment of Dredged Sediment
Authors: Yannan Shi , Chaojie Zhang , Jiongqi Yu , Mingli Tang
Published: June 2018

In order to improve water quality, to ensure the capacity of normal flood discharge and river transport, it carried out a lot of dredging work across the country recently. For harmful sediment’s second pollution and recycling use, this study selected five kinds of sediment. And point A was determined as the research object by using the geo-accumulation index to evaluate the heavy metal. Then the sediment was mixed with lime, fly ash, kaolin clay, sodium silicate, sodium carbonate and polyvinyl alcohol as mud stabilizing materials. Experimental research shows that, copper loss of stabilized soil’s toxicity leaching agent reaches more than 95%, and the permeability coefficient was 10-5 cm/s orders of magnitude. In this paper, it ensures GW7 as the best choice of plants experiments, which are 5% fly ash, 1% lime, 3% kaolin clay, 3% sodium silicate, 3% sodium carbonate and 1% polyvinyl alcohol, through the ways of permeability, water retention, SEM and XRD. The scheme effectively stabilizes copper, and keeps the plants as better form than others. But it has different effect on different plants. Thus it should consider planting varieties optimization in actual applications.
Research on the dynamic buckling of functionally graded material plates under conditions of one edge fixed and three edges simply supported
Authors: Xin Wang , Jun Han Zhi , Li Wu Ya
Published: June 2018

Based on the strain assumption and linear mixing rate of Vogit, the physical property parameter expression of functionally graded material plates is obtained. According to the theory of small deformation and Hamilton principle, the dynamic buckling governing equation of functionally graded material plates under longitudinal load is obtained. Using the method of trial function, the analytical expression of critical load and the buckling solution of the functionally graded material plate under conditions of one edge fixed and three edges simply supported is obtained. The analytical expression of critical load is numerically calculated by METLAB. The influence of geometric size, gradient index, modal order and material composition on critical load is discussed. The results show that the critical buckling load decreases exponentially with the increase of critical length, decreases with the increase of gradient index k, increases with the increase of modal order, and the elastic modulus of constituent materials has significant effect on the critical load. The higher-order buckling modes of functionally graded material plates are prone to occur under the condition of high longitudinal load.
Research on Extrusion of Rubber Composites Reinforced by Short Fibers Orientation Based on FEA
Authors: Zhang Dewei , Wang Chuansheng , Shen Bo , Li Shaoming , Bian Huiguang
Published: June 2018

In recent years, rubber composites reinforced by short fibers has been researched deeply, because of its good performances such as higher wear resistance, higher cut resistance and so on. Some research results indicated that if short fibers get orientation in rubber composites, the performances of rubber products could be promoted greatly. But how to make short fibers get orientation in rubber matrix during extrusion is still a real problem. And there are many parameters affect the short fibers orientation. So, in this paper, the effects of die structure including expansion-die and dam-expansion-die on extrusion flow field of short fiber and rubber composite material during extrusion process has been researched by Polyflow. And the FEA results about the pressure field, velocity field and the velocity vector of the rubber composites flow field indicate that, comparing with expansion-die and the dam-expansion-die, the latter one is better for the extrusion process of rubber composites and making short fibers get radial orientation in rubber matrix.
The Effect of Different Bags on Chlorophyll and Carotenoids in
the Peel of Chinhuang Mango
Authors: Zhi Ling Ma , Chang Bin Wei
Published: June 2018

The effect of different fruit bags on the content of chlorophyll and carotenoids in the fruit peel of Chinhuang mango during normal storage and after-ripening process was studied. The results showed that the content of chlorophyll and carotenoid in the bag was significantly lower than that of the control fruit. The skin color of the white paper bag fruit and the no bagged bag fruit was green during the green ripening process, while the outer yellow inner black paper bag fruit showed a yellow green halo. When ripe, the control fruit is yellowish green and orange red. The white paper bag fruit is greenish orange yellow, and the outside yellow inside black composite paper bag fruit is golden yellow.
Tool Efficiency Analysis model research in SEMI industry
Authors: Lei Ma , Nana Zhang , Zhongqiu Zhang
Published: June 2018

One of the key goals in SEMI industry is to improve equipment through put and ensure equipment production efficiency maximization. This paper is based on SEMI standards in semiconductor equipment control, defines the transaction rules between different tool states，and presents a TEA system model which is to analysis tool performance automatically based on finite state machine. The system was applied to fab tools and verified its effectiveness successfully, and obtained the parameter values used to measure the equipment performance, also including the advices of improvement.
Research on Bidding Decision-making of International Public-Private Partnership Projects
Authors: Hu Zhen Yu , Zhang Shui Bo , Liu Xin Yan
Published: June 2018

In order to select the optimal quasi-bidding project for an investment enterprise, a bidding decision-making model for international PPP projects was established in this paper. Firstly, the literature frequency statistics method was adopted to screen out the bidding decision-making indexes, and accordingly the bidding decision-making index system for international PPP projects was constructed. Then, the group decision-making characteristic root method, the entropy weight method, and the optimization model based on least square method were used to set the decision-making index weights. The optimal quasi-bidding project was thus determined by calculating the consistent effect measure of each decision-making index value and the comprehensive effect measure of each quasi-bidding project. Finally, the bidding decision-making model for international PPP projects was further illustrated by a hypothetical case. This model can effectively serve as a theoretical foundation and technical support for the bidding decision-making of international PPP projects.
Development of Simulation Program for Temperature Field of Mass Concrete Structures
Authors: Si Zheng , Zhang Qian , Huang Ling Zhi , Yang Dan
Published: June 2018

Most existing temperature field calculation programs have relative defects. In the present paper, based on merits of ANSYS platform, a temperature field calculation program of mass concrete structure is developed and demonstrated. According to actual pouring progress and thermodynamic parameters, a roller-compacted concrete dam is simulated. The difference of maximum temperature between calculated and measured values of measuring points is less than 1.8°C. Furthermore, the relative difference is -5%–5%. This result shows that the calculation program developed based on ANSYS platform can simulate and calculate the temperature field of mass concrete structure.
Cyclic Flexural Behavior of Reinforced Concrete Beams
Authors: Malla Prafulla B , Zhou Hong , Che Yi
Published: June 2018

The present study aims at investigating the cyclic flexural behavior of reinforced concrete beams with varying depths. Five reinforced concrete beams with beam depth ranging from 250 mm to 750 mm were tested under reversed cyclic loading and the influence of beam depth on the flexural strength and ductility of reinforced concrete beams was investigated. In addition, OpenSees was used to model the test specimens and the analytical results were compared with the experimental reuslts. It is shown that there is no apparent size effect on the normalized ultimate flexural strength of the tested beams, while for the displacement ductility factor, a significant size effect is observed. Load-deflection hysteric curves of test specimens obtained by the fiber-based element of OpenSees with Concrete03 and Hysteric models are in good agreement with those from experimental tests.
Monitoring calculation of closure change of Extradosed Cable-stayed Bridge
Authors: Shi Jing Xian , Ran Zhi Hong
Published: June 2018

During the construction of extradosed cable-stayed bridge in Yunnan province, China, the construction unit has made certain changes in the construction process of the closure section due to environmental restrictions: remove the hanging basket after the closure, the sling shall not be provided in closure section, the function of the sling is realized by the hanging basket on the 16th beam. In case of this change, the bridge has been constructed to section 15th. In order to ensure the smooth and orderly progress of each stage in the closure phase, this article is arranged according to the construction plan, appropriate adjustment of related procedures, checking the bridge safety at all stages of construction, the stress and force of the main girder are compared to ensure the safety of the construction after closure changes. Adjust the height of the beam of the 16th and 17th to adapt the new construction plan, and the bridge closure smoothly.
The Application of Deck Charge Technology in Hua Neng open pit Mine
Authors: Zhang Xiao Jun , Wang Xu Guang , Yu Ya Lun , Yang De Qiang
Published: June 2018

In the modern mine development and construction, how to improve the effective utilization of explosive energy, while achieving the requirements of the blasting vibration , is the key problem of blasting research.In this paper, from the actual situation of Huaneng open pit mine, for the complaints of nearby residents, the blasting program will be improved.First of all, the principle of the deck charge technology is analyzed, and then the deck charge technology is applied to the open pit mine to reduce the vibration caused by the blasting, to appease the dissatisfaction of the nearby residents. Finally It has achieved good results.
The analysis of dynamic characteristics and wind-induced displacement response of space Beam String Structure
Authors: Chen Yong Jian , Feng Zhen Fa , Qi Ai , Huang Ying
Published: June 2018

The Beam String Structure structural system, also called BSS, has the advantages of lighter dead weight and greater flexibility. The wind load is the main design control factor. The dynamic characteristics and wind-induced displacement response of BSS are studied by the finite element method. The roof structure of the stadium roof of the Fuzhou Olympic Sports Center is the engineering background. 1)The numerical model was built by ANSYS, by shape finding, determine the initial stress state of structural members such as external cables; 2)From the analysis of dynamic characteristics, the main mode of vibration is the vibration of cables; 3)The wind speed spectrum of MATLAB generation structure is obtained by AR method, the structural response of the structure under static wind load and fluctuating wind load is calculated. From the analysis result, considering the equivalent static wind load of BSS , the design of adverse wind is not safe, and the fluctuating wind load should be taken into account.
Study of stability against deep sliding of gravity dam based on JC method
Authors: Si Zheng , Xin Lanfang , Huang Lingzhi , Wang Zhengxin
Published: June 2018

In this study, stability against deep sliding of gravity dam is analysed in order to provide guidance for ensuring stability against sliding of gravity dam during the construction and operation periods. Based on checking-point method (JC method), the study proposes an analysis model for stability against deep sliding of gravity dams. In addition, the rigid body limit equilibrium method is utilized to construct the limit state function of deep anti-sliding stability. With sliding plane anti-shear friction coefficient and anti-shear cohesion calculated as random variables, safety degree of stability against deep sliding is analysed. With JC method employed, the calculation program is compiled to calculate the stability against deep sliding of gravity dam and analyse the non-overflow section of gravity dam under normal storage level. According to calculation program, the reliability index β of stability against deep sliding of gravity dam is 4.36, and the failure risk Pf is approximately zero. Additionally, based on the traditional rigid body limit equilibrium method, the safety factor K is 3.23, which meets the requirements of the design specification. According to the above methods, stability against deep sliding of the dam section meets the requirement. In conclusion, JC method provides a calculation and analysis model for gravity dam’s stability against deep sliding, serving as references in the design of gravity dams based on reliability theory.
Study on bridge checking evaluation based on deformation-Stress data
Authors: Shi Jing Xian , Cheng Ying Jie
Published: June 2018

Bridge structure plays a very important role in human traffic. The evaluation of bridge structure after a certain period of operation has always been the focus of the bridge. Based on the data collected from the health inspection system of a continuous rigid frame bridge on a highway in Yunnan, China, it is found that there is a certain linear relationship between the deformation and stress of the bridge structure. In view of a specific section of the structure, the stress value of this section can be derived according to its deformation value. The coefficient K can be calculated by comparing the estimated value to the actual measured value. According to the range of the K value, the structural state of the bridge can be evaluated to a certain extent.
Construction Simulation Analysis of 60m-span Concrete Filled Steel Tube arch bridge
Authors: Shi Jing Xian , Ding Qing Hua
Published: June 2018

The construction process of the CFST arch bridge is complicated. The construction process not only affects the structural stress in the installation, but also determines the form a bridge and internal force of the bridge. In this paper, a 60m span concrete filled steel tube tied arch bridge is taken as the background, and a three-dimensional finite element simulation model is established by using the MIDAS/Civil bridge structure analysis software. The elevation of the main arch ring, the beam stress, the forces in hanger rods and the modal frequency of the main arch during the construction stage are calculated, and the construction process is simulated and analyzed. Effectively and reasonably guide the construction and ensure that the line and force conditions of the completed bridge meet the design requirements and provides a reliable technical guarantee for the safe construction of the bridge.
Damage Model of Reinforced Concrete Members under Cyclic Loading
Authors: Wei Bo Chen , Zhang Jing Shu , Zhang Yin Hua , Zhou Jia Lai
Published: June 2018

Based on the Kumar damage model, a new damage model for reinforced concrete members is established in this paper. According to the damage characteristics of reinforced concrete members subjected to cyclic loading, four judgment conditions for determining the rationality of damage models are put forward. An ideal damage index (D) is supposed to vary within a scale of zero (no damage) to one (collapse). D should be a monotone increasing function which tends to increase in the case of the same displacement amplitude. As for members under large displacement amplitude loading, the growth rate of D should be greater than that of D under small amplitude displacement loading. Subsequently, the Park-Ang damage model, the Niu-Ren damage model, the Lu-Wang damage model and the proposed damage model are analyzed for 30 experimental reinforced concrete members, including slabs, walls, beams and columns. The results show that current damage models do not fully matches the reasonable judgment conditions, but the proposed damage model does. Therefore, a conclusion can be drawn that the proposed damage model can be used for evaluating and predicting damage performance of RC members under cyclic loading.
Solution of Thermoelectricity Problems Energy Method
Authors: Niyazbek Muheyat , Nogaybaeva M.O , Talp Kuenssaule , Kudaikulov A.A
Published: June 2018

On the basis of the fundamental laws of conservation of energy in conjunction with local quadratic spline functions was developed a universal computing algorithm, a method and associated software, which allows to investigate the Thermophysical insulated rod, with limited length, influenced by local heat flow, heat transfer and temperature
Typical Construction Technology and Method of UHV Main Transformer
Authors: Kerui Chen , Yang Han , Lei Wang , Ying Pei , Dengsen He , Yan Zhang , Nannan Gao , Hongbo Li , Pei Li , Liangfeng Guo
Published: June 2018

According to the latest experience of UHV transformer on-site installation work, according to the rules and regulations requirements, the construction process and process of UHV transformer are summarized, and a typical UHV transformer construction method commonly used at present is obtained. Operation comes down to the arrival of acceptance, annex installation, vacuum oiling and hot oil circulation, sealing inspection, standing five processes. In accordance with the above process steps, this paper is divided into five parts to introduce the process and method of UHV transformer construction in order to guide the on-site construction and training teaching.
Structural Statics Analysis and Optimization Design of Regulating Device for Air Conveyer Outlet in Coal Mine
Authors: Gong Xiaoyan , Li Ying , Zhang Yongqiang
Published: June 2018

In view of the enlargement of fully mechanized face excavation and long distance driving, gas emission and dust production increase greatly. However, the current ventilation device direction angle, caliber and front-back distance cannot change dynamically at any time, resulting in the serious accumulation in the dead zone. In this paper, a new device were proposed that can solve above problems. Finite element ANSYS software were used to simulate and optimize the structural safety of the control device' key components. The optimization results showed that the equivalent stress decreases by 49%; after the optimization of deformation and mass are 0.829mm and 0.548kg, which were 21% and 10% lower than before.The quality, safety, reliability and cost of the control device reach the expected standards perfectly, which can meet the requirements of safe ventilation and down-dusting of fully mechanized face.
Fluorescence enhancement and strong-coupling in faceted plasmonic nanocavities
Authors: Kongsuwan Nuttawut , Demetriadou Angela , Chikkaraddy Rohit , Baumberg Jeremy J. , Hess Ortwin
Published: June 2018

Emission properties of a quantum emitter can be significantly modified inside nanometre-sized gaps between two plasmonic nanostructures. This forms a nanoscopic optical cavity which allows single-molecule detection and single-molecule strong-coupling at room temperature. However, plasmonic resonances of a plasmonic nanocavity are highly sensitive to the exact gap morphology. In this article, we shed light on the effect of gap morphology on the plasmonic resonances of a faceted nanoparticle-on-mirror (NPoM) nanocavity and their interaction with quantum emitters. We find that with increasing facet width the NPoM nanocavity provides weaker field enhancement and thus less coupling strength to a single quantum emitter since the effective mode volume increases with the facet width. However, if multiple emitters are present, a faceted NPoM nanocavity is capable of accommodating a larger number of emitters, and hence the overall coupling strength is larger due to the collective and coherent energy exchange from all the emitters. Our findings pave the way to more efficient designs of nanocavities for room-temperature light-matter strong-coupling, thus providing a big step forward to a non-cryogenic platform for quantum technologies.
Temperature measurement and performance assessment of the experimental composting bioreactor
Authors: Bajko Jaroslav , Fišer Jan , Jícha Miroslav
Published: June 2018

Considerable amount of heat produced during composting of organic matter is usually lost to the surrounding environment. In order to utilize this potential heat source, biomass is composted in mounds or vessels and excess thermal energy is captured via heat exchangers and transported to the site for space heating, preparation of utility water and other applications. The aim of this experimental research is to measure the temperature profiles in a pilot-scale composting bioreactor and assess its performance.
Optimization of the cleaning process on a pilot filtration setup for waste water treatment accompanied by flow visualization
Authors: Bílek Petr , Hrůza Jakub
Published: June 2018

This paper deals with an optimization of the cleaning process on a liquid flat-sheet filter accompanied by visualization of the inlet side of a filter. The cleaning process has a crucial impact on the hydrodynamic properties of flat-sheet filters. Cleaning methods avoid depositing of particles on the filter surface and forming a filtration cake. Visualization significantly helps to optimize the cleaning methods, because it brings new overall view on the filtration process in time. The optical method, described in the article, enables to see flow behaviour in a thin laser sheet on the inlet side of a tested filter during the cleaning process. Visualization is a strong tool for investigation of the processes on filters in details and it is also possible to determine concentration of particles after an image analysis. The impact of air flow rate, inverse pressure drop and duration on the cleaning mechanism is investigated in the article. Images of the cleaning process are compared to the hydrodynamic data. The tests are carried out on a pilot filtration setup for waste water treatment.
High Temperature Modification of SNCR Technology and its Impact on NOx Removal Process
Authors: Blejchař Tomáš , Konvička Jaroslav , von der Heide Bernd , Malý Rostislav , Maier Miloš
Published: June 2018

SNCR (Selective non-catalytic reduction) Technology is currently being used to reach the emission limit for nitrogen oxides at fossil fuel fired power plant and/or heating plant and optimum temperature for SNCR process is in range 850 - 1050°C. Modified SNCR technology is able to reach reduction 60% of nitrogen oxides at temperature up to 1250°C. So the technology can also be installed where the flue gas temperature is too high in combustion chamber. Modified SNCR was tested using generally known SNCR chemistry implemented in CFD (Computation fluid dynamics) code. CFD model was focused on detail simulation of reagent injection and influence of flue gas temperature. Than CFD simulation was compared with operating data of boiler where the modified SNCR technology is installed. By comparing the experiment results with the model, the effect on nitrous oxides removal process and temperature of flue gas at the injection region.
Conjugate heat transfer for turbulent flow in a thick walled plain pipe
Authors: Canli Eyub , Ates Ali , Bilir Sefik
Published: June 2018

Laminar and turbulent flow have their own characteristics in respect of heat transfer in pipes. While conjugate heat transfer is a major concern for a thick walled pipe with laminar flow inside it, there are limited studies about a turbulent flow in a thick walled plain pipe considering the conjugate heat transfer. In order to conduct such a work by means of in-house developed code, it was desired to make a preliminary investigation with commercially available CFD codes. ANSYS CFD was selected as the tool since it has a positive reputation in the literature for reliability. Defined heat transfer problem was solved with SIMPLE and Coupled Schemes for pressure velocity coupling and results are presented accordingly.
The Influence of Surface Roughness on the Flow Fields Generated by an Oscillating Cantilever
Authors: Conway Ciaran , Punch Jeff
Published: June 2018

With the current trend of miniaturisation of electronic devices, piezoelectric fans have attracted increasing interest as a means of inducing forced convection cooling, instead of traditional rotary solutions. Although there exists an abundance of research on various piezo-actuated flapping fans in the literature, the geometries of these fans all consist of a smooth rectangular cross section with thicknesses typically of the order of 100 μm. The focus of these studies has primarily been on variables such as frequency, amplitude and, in some cases, resonance mode. It is generally noted that the induced flow dynamics are a direct consequence of the pressure differential at the fan tip as well as the pressure driven ‘over the top’ vortices generated at the upper and lower edges of the fan. Rough surfaces such as golf ball dimples or vortex generators on an aircraft wing have proven to be beneficial by tripping the boundary layer and energising the adjacent airflow. This paper aims to examine the influence of surface roughness on the airflow generation of a flapping fan, and to determine if the induced wake can be manipulated or enhanced by energising the airflow around the fan tip. Particle-Image Velocimetry (PIV) is carried out on mechanically oscillated rigid fans with surfaces consisting of protruding pillars and dimples. A smooth rigid fan surface is also investigated as a control. No significant difference was noted between the smooth and roughened fans through observation of the induced flow fields. Both fans produced results that were largely consistent with the existing literature on oscillating cantilevers. The results of this paper may be used to inform the design of piezoelectric fans and to aid in understanding the complex aerodynamics inherent in flapping wing flight.
Temperature profiles measurements in turbulent Rayleigh-Bénard convection by optical fibre system at the Barrel of II-menau
Authors: Drahotský Jakub , Hanzelka Pavel , Musilová Věra , Macek Michal , du Puits Ronald , Urban Pavel
Published: June 2018

Modelling of large-scale natural (thermally-generated) turbulent flows (such as the turbulent convection in Earth’s atmosphere, oceans, or Sun) is approached in laboratory experiments in the simplified model system called the Rayleigh-Bénard convection (RBC). We present preliminary measurements of vertical temperature profiles in the cell with the height of 4:7 m, 7:15m in diameter, obtained at the Barrel of Ilmenau (BOI), the worldwide largest experimental setup to study highly turbulent RBC, newly equipped with the Luna ODiSI-B optical fibre system. In our configuration, the system permits to measure the temperature with a high spatial resolution of 5mm along a very thin glass optical fibre with the length of 5m and seems to be perfectly suited for measurement of time series of instantaneous vertical temperature profiles. The system was supplemented with the two Pt100 vertically movable probes specially designed by us for reference temperature profiles measurements.
Radioisotope measurements of the liquid-gas flow in the horizontal pipeline using phase method
Authors: Hanus Robert , Zych Marcin , Jaszczur Marek , Petryka Leszek , Świsulski Dariusz
Published: June 2018

The paper presents application of the gamma-absorption method to a two-phase liquid-gas flow investigation in a horizontal pipeline. The water-air mixture was examined by a set of two Am-241 radioactive sources and two NaI(Tl) scintillation probes. For analysis of the electrical signals obtained from detectors the cross-spectral density function (CSDF) was applied. Results of the gas phase average velocity measurements for CSDF were compared with results obtained by application of the classical cross-correlation function (CCF). It was found that the combined uncertainties of the gas-phase velocity in the presented experiments did not exceed 1.6% for CSDF method and 5.5% for CCF.
Additional effects of fluid on the piston
Authors: Himr Daniel , Habán Vladimír , Kůrečka Jan , Pochylý František
Published: June 2018

Additional effect of fluid on the solid body is often ignored phenomenon. Although it is possible to do an analytic derivation of equations describing additional effects for many various conditions, it can be difficult to solve them. The paper shows pressure pulsations in the pipe with piston solved by transfer matrix and harmonic analysis with ANSYS Acoustics, where effect of second viscosity is included.
Compiled visualization with IPI method for analysing of liquid liquid mixing process
Authors: Jasikova Darina , Kotek Michal , Kysela Bohus , Sulc Radek , Kopecky Vaclav
Published: June 2018

The article deals with the research of mixing process using visualization techniques and IPI method. Characteristics of the size distribution and the evolution of two liquid-liquid phase's disintegration were studied. A methodology has been proposed for visualization and image analysis of data acquired during the initial phase of the mixing process. IPI method was used for subsequent detailed study of the disintegrated droplets. The article describes advantages of usage of appropriate method, presents the limits of each method, and compares them.
Experimental Investigation of the Boundary Layer Transition on a Laminar Airfoil Using Infrared Thermography
Authors: Jelínek Tomáš
Published: June 2018

The transition in the boundary layer is investigated using infrared thermography (IRT). The study is carried out on a laminar airfoil in the transonic intermittent in-draft wind tunnel. The transition in the boundary layer is evocated using transition-generator strips of different thicknesses at two Mach numbers: 0.4 and 0.8. The tested transition-generators thickness to boundary layer displacement thickness ratio was from 0.42 to 1.25. The Reynolds number respect to the airfoil chord is: Re = 1.0 – 1.4·106. The six cases for different transition-generators thickness ratios were compared. The behaviours of laminar and turbulent boundary layers are discussed. The use of IRT has been proven to be an appropriate tool for detecting the transition of the boundary layer in high-speed wind tunnel testing.
Comparison of heat transfer coefficients of open micro-channels and plain micro-fins
Authors: Kaniowski Robert , Pastuszko Robert
Published: June 2018

The paper describes results of analysis of pool boiling heat transfer on enhanced surfaces. Two types of structural surfaces were used: open microchannel surfaces consisting of a system of parallel micro-channels 0.3 mm wide, from 0.2 to 0.5 mm deep and with a pitch of 0.6 mm, and plain micro-fins 0.5 mm in height, uniformly spaced on the base surface with a spacing from 0.6 to1.5 mm. Pool boiling data at atmospheric pressure were obtained for saturated water, ethanol and FC-72. The effects of micro-channel/micro-fin dimensions on heat transfer coefficient in nucleate pool boiling were examined. Substantial enhancement of heat transfer coefficient was observed.
Pool boiling of ethanol and FC-72 on open microchannel surfaces
Authors: Kaniowski Robert , Pastuszko Robert
Published: June 2018

The paper presents experimental investigations into pool boiling heat transfer for open microchannel surfaces. Parallel microchannels fabricated by machining were about 0.3 mm wide, and 0.2 to 0.5 mm deep and spaced every 0.1 mm. The experiments were carried out for ethanol, and FC-72 at atmospheric pressure. The image acquisition speed was 493 fps (at resolution 400 × 300 pixels with Photonfocus PHOT MV-D1024-160-CL camera). Visualization investigations aimed to identify nucleation sites and flow patterns and to determine the bubble departure diameter and frequency at various superheats. The primary factor in the increase of heat transfer coefficient at increasing heat flux was a growing number of active pores and increased departure frequency. Heat transfer coefficients obtained in this study were noticeably higher than those from a smooth surface.
Study of the nozzle check valve with respect to its operating characteristics
Authors: Klas Roman , Habán Vladimír , Rudolf Pavel
Published: June 2018

Several modifications were developed when designing the nozzle valve. This study offers an assessment of the properties of new modifications of the nozzle valve design. The main operating characteristics, such as loss and flow coefficients, were determined using a CFD methods. Besides mentioned coefficients, the forces acting on the valve disc are also decisive for the behavior of the valve, both in its steady and unsteady operation. It is important to examine the possible simplification and matching of CFD simulation results from 2D and 3D geometries in terms of subsequent dynamic analysis of the valve. This will be taken into consideration by comparing the above-mentioned operating characteristics, by analyzing the forces acting on the valve disc and comparing the velocity and pressure fields.
Experimental and Numerical Study on Supersonic Ejectors Working with R-1234ze(E)
Authors: Kracik Jan , Dvorak Vaclav , Nguyen Van Vu , Smierciew Kamil
Published: June 2018

These days, much effort is being put into lowering the consumption of electric energy and involving renewable energy sources. Many engineers and designers are trying to develop environment-friendly technologies worldwide. It is related to incorporating appropriate devices into such technologies. The object of this paper is to investigate these devices in connection with refrigeration systems. Ejectors can be considered such as these devices. The primary interest of this paper is to investigate the suitability of a numerical model for an ejector, which is incorporated into a refrigeration system. In the present paper, there have been investigated seven different test runs of working of the ejector with a working fluid R-1234ze(E). Some of the investigated cases seem to have a good agreement and there are no significant discrepancies between them, however, there are also cases that do not correspond to the experimental data at all. The ejector has been investigated in both on-design and off-design working modes. A comparison between the experimental and numerical data (CFD) performed by Ansys Fluent software is presented and discussed for both an ideal and a real gas model. In addition, an enhanced analytical model has been introduced for all runs of the ejector.
Validation of laser-penetration- and electrical-conductivity-based methods of concentration measurement in flow with intense transport of coarse sediment
Authors: Krupička Jan , Matoušek Václav , Picek Tomáš , Zrostlík Štěpán
Published: June 2018

Lack of experimentally determined information on inner structure of flows carrying large amount of coarse sediment is an important limitation for development and validation of appropriate mathematical models. Measurement of local flow properties is particularly difficult in case of coarse sediment due to specific features associated with high ratio of the sediment size to the flow depth. This paper focusses on two methods of evaluation of vertical concentration profiles in the flow of a mixture of plastic grains and water in a laboratory flume. The first one was proposed by B. Spinewine et al. in 2011 and it is based on the relation between concentration of solids and the depth of penetration of a laser stripe to the flow, which is evaluated from a high speed camera record. The second method is based on well-known relation between the concentration and electrical conductivity of a mixture sensed by immersed probe. A sensitivity analysis of both the methods is performed to show the most crucial parameters affecting accuracy of the results. The methods are validated on data measured in fluidization cell with controlled particle concentration. Presented results on flow show limitations and potential of the methods for laboratory studies on liquid-granular flow.
Experimental Characterization of the Jet Wiping Process
Authors: Mendez Miguel Alfonso , Enache Adriana , Gosset Anne , Buchlin Jean-Marie
Published: June 2018

This paper presents an experimental characterization of the jet wiping process, used in continuous coating applications to control the thickness of a liquid coat using an impinging gas jet. Time Resolved Particle Image Velocimetry (TR-PIV) is used to characterize the impinging gas flow, while an automatic interface detection algorithm is developed to track the liquid interface at the impact. The study of the flow interaction is combined with time resolved 3D thickness measurements of the liquid film remaining after the wiping, via Time Resolved Light Absorption (TR-LAbs). The simultaneous frequency analysis of liquid and gas flows allows to correlate their respective instability, provide an experimental data set for the validation of numerical studies and allows for formulating a working hypothesis on the origin of the coat non-uniformity encountered in many jet wiping processes.
Gas dispersion modelling in a critical infrastructure area
Authors: Michálek Petr , Zacho David , Žižkovský Nikola
Published: June 2018

Experimental investigation of gas dispersion in a critical infrastructure area was performed using a boundary layer wind tunnel. The dispersion of gases is evaluated from the point of view on required function of security systems in case of critical infrastructure accident involving airplane attack. Physical model of the critical infrastructure installed in the wind tunnel is subjected to measurement of gas concentration with flame ionisation detectors.
On the spray pulsations of the effervescent atomizers
Authors: Mlkvik Marek , Knizat Branislav
Published: June 2018

The presented paper focuses on the comparison of the two effervescent atomizer configurations—the outside-in-gas (OIG) and the outside-in-liquid (OIL). The comparison was based on the spray pulsation assessment by different methods. The atomizers were tested under the same operating conditions given by the constant injection pressure (0.14 MPa) and the gas to the liquid mass ratio (GLR) varying from 2.5 to 5%. The aqueous maltodextrin solution was used as the working liquid (μ = 60 and 146 mPa·s). We found that the time-averaging method does not provide sufficient spray quality description. Based on the cumulative distribution function (CDF) we found that the OIG atomizer generated the spray with non-uniform droplet size distribution at all investigated GLRs. Exceptionally large droplets were present even in the spray which appeared stable when was analyzed by the time-averaging method.
Influence of yaw on propeller aerodynamic characteristics
Authors: Nguyen Van Bang , Rozehnal Dalibor , Hnidka Jakub , Pham Vu Uy
Published: June 2018

Between the propeller axis and free stream direction, it can still be a non-zero yaw angle. This paper introduces some propeller experiments, in which the propeller aerodynamic characteristics have been determined in various yaw angle and different rotational speeds. The experimental aerodynamic characteristics are acquired dynamic values, from which the influence of yaw conditions on the frequency and the amplitude of propeller thrust and torque can be obtained.
Investigation of the impact of Photovoltaic Sizing and Siting Modeling on Micro-grids Energy Management Optimization
Authors: Abuelnasr Marwa , El-Khattam Walid , Helal Ibrahim
Published: June 2018

The modeling of micro-grid’s PV units’ and loads’ size and distribution along its network could severely affect the accuracy of power losses calculation and; thus the amount of energy to be imported from the main-grid to balance the load. Also, it will affect the micro-grid’s optimal energy management results. Therefore, a comprehensive analysis is carried out to assess the impact of the PV’s and the load’s sizing and sitting (either lumped or distributed). Four case studies are carried out to illustrate the impact of the modeling on the micro-grid’s losses and the imported energy from the main-grid and their costs. The obtained results are used to implement the proposed energy management two-single objective optimization functions applying Genetic Algorithm. Then, a fifth case study is carried out to optimize the micro-grid energy management process through an optimal chagrining - discharging scheduling of a storage module. The obtained results, recommendations, and evaluations for choosing a proper sizing and siting modeling and the chagrining - discharging scheduling of a storage module under seasonal variations are reported and discussed.
Hidden High Voltage Safety Risks for Parallel High Voltage Transmission Lines
Authors: Nassereddine M. , Rizk J. , Nagrial M. , Hellany A. , Moubayed N. , Karami N.
Published: June 2018

High voltage (HV) infrastructures market is growing due to the corresponding growth in industries and population. To ensure continuous and reliable electrical power supply, existing substation and transmission lines are being upgraded to accommodate the additional load requirements. These upgrades involve up-rating the existing transmission lines or the installation of new lines. To save on easement cost and reduce the environmental impacts, transmission lines are occupied the same easement or path. This parallel option introduces the risk of induced voltage which could reach an unsafe condition and jeopardize the safety of works and people. This paper analysis and highlight the hidden risk associated with two parallel transmission lines that connected the same high voltage substation. The theoretical study which is supported by the case study shows the high risk potential tempering with the OHEW on the isolated circuit while the other one is still energized
Influence of Processing Parameters on the Tensile Strength of PA-W/mLLDPE Composite Films Produced by Blown Film Extrusion
Authors: Zgheib Nancy , Tahan Doumit , Seif Sylvain , El Hajj Nemr
Published: June 2018

Extrusion blown films from Polyamide waste/metallocene linear low-density polyethylene (PAW/mLLDPE) blend based matrix system and calcium carbonates particles were successfully produced and characterized. Also, the effect of the extruder temperature used during twin-screw compounding, the coupling agent loading and PA loading on the mechanical properties of the obtained films were studied. The key aspect of the present study was in investigating the optimal combination of factors by using Design of Experiment (DOE) approach. The responses measured were the tensile strength in the machine direction (MD) and the tensile strength in the transverse direction (TD). Among the selected processing parameters, the coupling agent and the interaction between the coupling agent and the PA loading have the most important influence on the tensile strength.
Effects of Formation Brine Compositions on Effectiveness of Low Salinity Brine Injection in Carbonate Reservoir
Authors: Meekangwal Suthida , Srisuriyachai Falan
Published: June 2018

Nowadays, Low Salinity Waterflooding (LSWF) is considered as one of the most effective techniques to enhance oil recovery. Essential mechanism is a Multi-Ion Exchange (MIE). In carbonate formation, collaboration of Potential Determining Ions (PDI) with rock surface and crude oil results in adjustment of surface equilibrium. These ions in injected brine are thoroughly investigated but effects from formation brine are not well documented. In this study, ratio of divalent ions including calcium and magnesium ions in formation brine is studied. Results from imbibition test shows that formation brine containing calcium ion to magnesium ion ratio of 1:1 yields response to LSWF. Oppositely, formation brines with high ratios of 10:1 and 15:1 do not respond to LSWF. As calcium ion in connate water diffuses to injected water, high calcium ion will exhibit dissolution mechanism of rock surface which is part of oil recovery mechanisms. Formation brine with high calcium ion is therefore not recommended for LSWF. High portion of magnesium ion in formation brine does not affect effectiveness of LSWF. Dissolution of magnesium from rock may be obstructed but oil can still be liberated from calcium carboxylate complex and dissolution of calcium. Coreflood test shows similar result which confirms previous explanation.
Carbon Dioxide Emissions Monitoring in Romania in the Context of Greenhouse Gases Reduction
Authors: Lazăr Avram , Tudora Cristescu , Monica Emanuela Stoica
Published: June 2018

The weather changes we are currently witnessing, characterised by dynamism and extreme phenomena, are the direct and indirect result of human activities which are determining the global atmosphere change in composition. The paperwork follows the evaluation and comparison of carbon dioxide emission coefficient in case of liquid oil fuels burning. The calculus model used for the carbon dioxide emission coefficient evaluation has been developed based on mathematical models from specific publications. It was applied in the case study based on data from specific literature. The results obtained following the evaluation allowed certain comparisons in the field of carbon dioxide emissions in case of the complete burning of certain fluid hydrocarbons use in industry.
Die böse Tat – deliktrelevante psychische Störungen und
ihre Behandlung
Authors: Saimeh Nahlah
Published: June 2018

Die meisten Menschen haben eine Vorstellung davon, was „böse“ ist. Woher aber
„das Böse“ kommt, beschäftigt den Menschen, seit er über sich und die
Gesellschaft, in der er lebt, reflektieren kann. Welchen Blick auf „das Böse“
hat die Forensische Psychiatrie? Warum es „das Böse“ gibt, kann die Forensik
nicht erklären. Welche Eigenschaften ein Täter aber hat und wie man
Rückfallstraftaten verhindert, dazu kann die Forensik einen Beitrag leisten.