bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduction of PM10 Emission from A Retrofitted Multicyclone
Authors: Dewika M. , Rashid M. , Khairuninisa M.P. , Ruwaida J. , Sara Y.Y.
Published: August 2019

Multi-cyclone is one of the particulate control systems commonly used in the industry due to its low capital, operating, and maintenance cost as well as its reliability under a wide range of operational conditions. Unfortunately, it has low performance in collecting fine particulate especially of less than 10 µm in diameter or PM10. Thus, this limitation motivated a cost-effective retrofit of the existing conventional multi-cyclone. The retrofit was performed by creating a more negative pressure at the dust hopper of a conventional multi-cyclone, by drawing out a small portion of the air using an Induced Draft Fan. The particulate emission concentration and overall collection efficiency of the unit at various effective inlet velocities ranging from 6.2 to 19.8 m/s with particulate loading of 30 mg/m3 of 100 µm sample size diameter of Palm Oil Mill Boiler Fly Ash were investigated in this study. Interestingly, the introduction of suction increased the overall performance of the multi-cyclone by 10 to 20%. The finding suggests that a simple retrofit managed to increase the overall performance of the conventional multi-cyclone even for PM10.
Possibilities of fly ash activation in alumina recovery process
Authors: Marko M , Opravil T , Masilko J , Porizka J
Published: August 2019

This paper summarises various possibilities of high-temperature fly ash (HTA) and fluidised-bed filter ash (FFA) activation in metal and oxides recovery processes (esp. alumina recovery). The study deals with chemical and phase composition ash modification to improve leachability of aluminium compounds into sulphuric acid solution. Samples of HTA and FFA produced by power plant industry in the Czech Republic were subjected to diverse types of modification, such as sulphuric acid concentration, ash/acid ratio and sintering reactions using several types of solid agents. Sintering reaction were based on forming acid soluble calcium aluminates via donating the system with calcium oxide, - carbonate and - chloride. Phase and chemical composition were characterised by means of XRD and XRF analysis and the concentration of Al in acid solutions via ICP–OES. Appropriate modification of input material by high-temperature sintering reaction using calcium chloride combined with extraction into 10 wt. % sulphuric acid leads to dissolution up to 99% of aluminium from FFA and up to 94% form HTA. At least, irreplaceable dopant for cement production – gypsum, is formed as a by-product of leaching.
Stabilisation of belite prepared from modified limestone waste sludge
Authors: Rybova A , Kubatova D , Zezulova A
Published: August 2019

Presenting work deals with the use of waste materials - waste sludge from mining and washing of limestone and waste material from acetylene gas cylinders containing mainly tobermorite and xonotlite. Both materials were characterized by X-ray powder diffraction, laser granulometry and chemical analysis. After drying and milling of raw materials, they were mixed together and homogenised resulting in 3 sample series with different ratios of these materials. The mixtures were then burned at 1150°C and 1350°C and the main products formed were lime, dicalcium silicate, wollastonite, pseudowollastonite and gehlenite. To preserve hydraulically active belite, K2O as stabilizing agent was added in amount of 1 and 3 wt. %. Burned products were studied by means of X-ray diffraction and optical microscopy. Also hydration was observed.
Development of lightweight composites based on foam glass aggregate
Authors: Zach J , Sedlmajer M. , Bubenik J , Drdlova M
Published: August 2019

Building composites based on various types of lightweight aggregate have been widely used in the last decades for production of precast elements (e.g. panels) or whole structures with a good thermal insulation/mechanical properties ratio. The presented research investigated the feasibility of using foam glass aggregate, prepared from waste glass powder, in lightweight insulating composites for building industry. The effect of various binders (both organic and inorganic), binder/filler ratios and 3 types of fibres addition (PET, cellulose and mineral wool waste) on the physico-mechanical properties (bulk density, compressive strength) and thermal conductivity of the composite was evaluated. The results indicate, that applicable composites with sufficient mechanical parameters and low thermal conductivity (coefficient of thermal conductivity about 0,09 W/(m·K) can be prepared using both types of binders.
Rheological properties of belite-rich cement doped with sulfur
Authors: Bohac M , Kubatova D , Rybova A , Zezulova A , Stanek T
Published: August 2019

Reactive belite cement based on clinker doped with sulfur is a new type of low-energy cement that is still in the laboratory testing phase. In terms of application, one of the desired properties of new cement is its well-defined rheological behavior in fresh state. The chemical composition of the belite cement was determined by wet chemistry analysis, the phase composition of the belite cement clinker by quantitative X-ray powder diffraction analysis and microscopic point counting and specific surface by Blaine method. Rheological properties were determined by rotational rheometer in flow and oscillation regime. Shear and time dependent rheological parameters were calculated from flow curves. Stability of belite cement paste was judged based on the critical strain determination in amplitude sweep test. Setting was evaluated by Tussenbrock needle penetration test and oscillation time test on rheometer. The properties of the laboratory belite cement were correlated to industrial cement CEM I, CEM II/A-LL and CEM III/A. Reactive belite cement pastes show good flow properties both due to small amount of alite and larger amount of rounded belite grains and clusters. Belite rich cement show decent stability comparable to CEM III and very good dispersing efficiency of PCE based HRWR.
Influence of sealing gasket distortion on diesel engine injection pump mounting
Authors: Bistriceanu D P , Bujoreanu C
Published: August 2019

Currently, the common-rail injection system is composed from a high-pressure pump, injectors, an electronic control unit and a common rail. Over time, the common-rail system has been simplified and optimized, but it remains that the high-pressure pump can still be affected by distortion which occurs during the pump assembly process and in turn has an effect in mounting the pump to the engine. The main assemblies of the diesel pump are the front plate, housing, driveshaft and hydraulic head. Our paper presents a solution for minimizing the distortion and also any external leaks that may occur due to a change in design of the sealing gasket between the body and front plate. This modification realizes the connection interface with the engine block and facilitates the pump mounting. The tests analysis is performed on high pressure pumps to determine where and when the distortion occurs.
Classic or unconventional cotton yarns?
Authors: Bucevschi A , Fogorasi M S , Nicolaescu C , Barbu I
Published: August 2019

In this paper we compared a classic and an unconventional system for the manufacturing of cotton yarns 100%. For this comparison we analyzed the complexity of classical and unconventional technological lines, the differences between the yarn structures, the fields of use of the yarns, as well as a cost-benefit analysis.

From the point of view of the complexity of the technological lines and implicitly of all the necessary adjustments we can say that the technological line for the unconventional system is much easy and shorter. Considering the complexity of technological lines, we can say that the human resources requirement is much lower for unconventional technological lines. For this we realised a comparative calculation of costs for workers and for taxes that an employer has to pay. Starting from the complexity of the technological lines, the unconventional technological line being shorter with two machines, we made a comparative calculation of the energy consumption. The calculations were made for a spinning mill with a production of 4000 t/year, a typical production for a medium size. From the point of view of the production costs and investment effort, we can say that the unconventional system is better, but considering the structure of the yarns we can say that the destinations are different, so the unconventional yarns are better suited to certain products, such as the jeans clothing.
Mixed-model assembly line balancing problem with tasks assignment
Authors: Dziki K , Krenczyk D
Published: August 2019

Modern production systems are focused on the objectives dictated by customer needs oriented market. The best results are obtained by production systems combining the advantages of mass production with the possibility of implementing product variants corresponding to the needs of an individual customer. An Example of the production system that meets those conditions is mixed-model assembly line. The main problem of this solution is to plan the order of operations and assign the operators’ tasks in such a way to obtain the best balance of a given line. In this study, several metaheuristic methods that can be used to solve line balancing and tasks assignment problems are presented. The purpose of this study is to show the advantage of simulated annealing over other methods in solving the described problem. This paper is introduction to future research in scope of mixed-model assembly line optimization focused on employees’ effectiveness.
Study on the influence of the working regime on the quality of cut in the case waterjet processing of S 235 steel
Authors: Herghelegiu E , Radu M C , Schnakovszky C , Chirita B A , Tampu N C
Published: August 2019

The current paper presents the influence of different working regimes on the quality of cuts performed by abrasive water jet processing on S 235 steel. Four process parameters were varied: pressure (P), feed rate (Vf), quantity of abrasive material (Q) and distance between the cutting head and workpiece (h). Four quality parameters were analysed: width of the processed surface at the jet inlet (Li), width of the processed surface at the jet outlet (Lo), inclination angle of cut (α) and surface roughness (Ra). The analysis was done for three material thicknesses: 1mm, 6.5mm and 10mm.
Theoretical and experimental contributions on ultrasonic contactless examination of underground pipes through which pressurized fluids circulate
Authors: Nitoi D , Amza Gh , Petrescu V , Amza Z , Chivu O
Published: August 2019

In any civil or industrial construction, there are many embedded pipelines through which pressurized fluids or gases are circulate and which, over time, are subject to corrosion. Examination and monitoring of corrosion/erosion process in order to determine the service life of pipelines through which fluids circulate at different temperatures and / or pressures is a particularly important task for both the designer and the owner because knowledge of “health status” of these in time is extremely. On-site ultrasound control of wall thickness is based on simple propagation time measurements and is typically used to evaluate corrosion and erosion. The paper presents a non-destructive control used to determine pipe corrosion and lifetime, most notably ultrasonic examination without contact, using Lamb dispersing waves. For experimentation, the most important zones of a pipeline were chosen. Thus, methods of examination for 90° pipe elbow, welded pipe sections, reduction pipes, and seamless pipe sections have been established. The main parameters that have been taken into account are: actual and effective phase angle, temperature of the environment, roughness of the controlled surfaces, geometry of the controlled surfaces and the nature of the fluid flowing through the pipes (air, liquid or steam).
Research on the welding possibilities of dissimilar welded joints between two special alloys
Authors: Rontescu C , Cicic D T , Nitoi D F , Petriceanu C
Published: August 2019

Continuous development of the technological processes led to the necessity of using industrial equipment/installations made of high temperature resisting materials that provide the ability to work in heavily corrosive environments. The paper analyses two fusion welding options of dissimilar welded joints between two alloys, a cobalt based and a nickel based alloy. Here in are presented the results obtained after welding the two different materials using Tungsten inert gas (TIG) and Electron beam (EBW). Based on the results obtained after micrographic and macrographic examinations, it has been concluded that the two welding processes can be successfully used at dissimilar welded joints between the two types of material.
The influence of the rolling direction on the elastic characteristics of the bending samples
Authors: Stanciu M D , Bucur R. , Teodorescu H Draghicescu , Savin A
Published: August 2019

There are a number of factors influencing the bending process such as: the rolling direction of the blank; the minimum bend radius of the piece; the radii of the bending plate (of the mold); the play between the die and the punch, the recoverable strain of the piece after bending. The paper presents the experimental results regarding the influence of the lamination direction on the rheological behaviour of the cold bending parts, using the Lloyd LS100 Plus universal machine and the Nexygen Plus program. Thus, two categories of samples were analyzed: some being cutted off in the direction of rolling of the sheet at which the bending occurred on an axis perpendicular to the direction of rolling and others cutted on cross direction of rolling, the bending being produced along the axis parallel to the rolling direction. As an elasto-plastic process, after the loading process during experiment, the samples recorded an elastic strain recovery due to the kinetic energy stored during stresses. Thus, the recovered elastic deformation (springback) is more pronounced in the case of specimens cutted of in cross direction on the rolling fiber where the bending moment is produced in the direction parallel to the laminating fiber of materials.
Novel approach to semi-automated warehouse for manufacturing: design and simulation
Authors: Bartkowiak T , Kunc T , Kluska K , Myszkowski A , Pabiszczak S
Published: August 2019

The purpose of this paper is to present a novel design of semi-automated warehousing system for manufacturing applications. The approach bases on a new type of storage of carriers, called drawer racks. This concept adopts a modified shelving system based on single or double sections of row racks rotated by 90 degrees. Each drawer rack can move perpendicularly to the transportation corridor. The motion of the rack is possible thanks to the automatically guided vehicle that translates under the line of racks. In the paper, we show a comparison between the designed new system and conventional storage solutions for manufacturing. This indicates that the drawer racks require less space per pallet place without a significant interference with a building infrastructure. In this work, we discuss various design solutions for key components of the drawer-rack and AGV that can operate a rack of 40 pallet places. The designed system was tested if it meets the assumed performance level. The simulation model was created in discrete event system environment. We compared the warehouse layout and material flow for conventional row racks with the newly proposed system. We found out that the new system operates at the higher efficiency but requires less space.
Evaluation of the performance of an automated metallographic samples analysis system by means of Petri Nets modelling
Authors: Blaga F S , Vesselenyi T , Ursu M P , Hule V , Stanasel I
Published: August 2019

This paper presents the results of the research about the automation of the metallographic samples preparation and analysis processes. At the University of Oradea the authors designed and made an automated metallographic samples preparation and analysis system. This automated system can achieve polishing, attack by reagents and metallographic analysis. The flexible cell (the automated system) is made of two subsystems. The first subsystem, which is served by an industrial robot, performs the polishing and the sample surface assessment. The second subsystem, also served by an industrial robot, performs the reagent attack and finishes the metallographic analysis in order to determine the microstructure of the sample. The authors have designed a timed Petri nets model in order to assess the performance of the automated system and to identify the possible bottlenecks. The model is made for the case that the system is required to analyse two kinds of samples. The sequences performed by the industrial robots are modelled by transitions with associated timings that are equal to the real time periods taken by the robots to execute the corresponding actions. Other activities, such as grinding polishing, finishing polishing, reagent attack, washing, microscope examining, have been also modelled by means of transitions. The execution of a transition (the completion of a real sequence) is possible if certain conditions are met. These conditions are modelled into the Petri net by means of positions. The number of samples that can be analyzed in a certain time period can be determined by simulation.
A numerical approach in the assessment of a new class of fluids performance in laminar flow
Authors: Chereches E I , Chereches M , Minea A A , Prado J I , Lugo L
Published: August 2019

The present paper focuses on the analysis of the thermal conductivity for both base fluid and their ionanofluids. Sequently, an analysis of the new heat transfer fluids behavior in laminar flow was performed to compare the experimental and theoretical results. In terms of experimental, the results showed a higher thermal conductivity for the ionanofluids with the highest nanoparticles concentration. Plus, the thermal conductivity is decreasing slightly with nanoparticles mass fraction while it is almost constant with increasing temperature. On the other hand, in the case of thermal conductivity theoretically determined, this is decreasing with increasing temperature. Furthermore, Mouromtseff number was used to evaluate the relative heat transfer capacity of different fluids. Higher Mouromtseff indicates a better heat transfer capacity of a certain fluid compared to a regular one. Concluding, the present study compared the thermal conductivity for base fluid and Al2O3 dispersed in [C2mim][CH3SO3]:H2O in the particle concentration range of 1–10 % wt and temperatures between 283.50 and 333.38 K. The results demonstrate that the thermal conductivity enhances with concentration increase. The maximum thermal conductivity enhancement of 10.2% was found for 10 % wt of ([C2mim][CH3SO3]:H2O) + Al2O3 ionanofluids. An increased Mouromseff number was noticed for theoretical thermal conductivity.
Classic spark simulation using COMSOL software
Authors: Hnatiuc B , Sabau A , Astanei D
Published: August 2019

New surface treatments for maritime domain using clean technologies have been proposed. Among these technologies there are non-thermal plasmas produced at atmospheric pressure. The spark discharge produces such plasma by adapting the classic spark plug to a laboratory plasma minireactor and using an induction coil and a command circuit as power supply, adjusting the power and consequently the energy of the discharge.

The spark discharge produced at atmospheric pressure has been diagnosed by classical methods, starting from the electrical parameters and the optical parameters (Optical Emission Spectroscopy method). The parameters that have been determined are: the reduced electric field, the rotational temperature, the vibrational temperature, the electron density and the electron temperature.

This study proposes a COMSOL simulation using Plasma Module introducing as initial or boundary values the experimental data such discharge voltage, reduced electric field, maximum voltage, initial number of electrons or ions etc. It was assumed the hypothesis of Local Field Approximation (LFA) in order to solve the Maxwell equation and few elementary processes concerning more the electron influence than the ions influence. The final results indicate the spatial and temporal evolution of the electron density, the electron temperature and the electric field. The simulated data are in good agreement with the data obtained from the experimental values.
Influence of the electric discharge and the power supply on the aqueous solution interface parameters
Authors: Lungu C V , Hnatiuc B
Published: August 2019

Laboratory electrical discharges that produce non-thermal plasma are used more and more for microbiological decontamination, surface treatment and depollution by the means of decomposing some complex molecules or in the field of modern medicine. Each application requires a power supply particularly adapted to the plasma reactor type used. If the first applications of these discharges were designed mostly for reactor types with high volume discharge capabilities, and the power supplies were simple and robust generating high power using industrial frequencies, in time the reactors decreased significantly in size and the power supplies used were working on higher frequencies. This trend was adopted on one hand out of the need for energy optimization of the power supplies used, and on the other hand for obtaining a better homogeneity of the treatment. This paper aims to provide a comparison of few AC and pulsed power supplies, working at different frequencies, with respect to the electrical parameters, from the point of view of active species production. The measured electrical parameters of the electrical discharges are the power and the specific energy. Also the results obtained for treatment of distilled water using three types of plasma reactors (classic GlidArc, Mini-torch plasma and Gliding Spark) will be shown. The analysis focus on the modification of pH of the distilled water in time after the plasma treatment.
The use of the NX mechatronic module to simulate of a simple machine work
Authors: Lysek K , Gwiazda A , Herbus K
Published: August 2019

Mechatronic is combination of three main disciplines like mechanic, electronic and theory of control. CAD/CAM systems is part of them. The aim of this article is to describe how to use CAD system (NX Siemens) with mechatronic module to designee simulation process. That module allows to resolve problems from mechanical, electrical and automation discipline. As an example author creates simple machine using this module. That aim was established in that form has been obtained. The created simulation is working and allowing to resolve mechanical robot’s problems. The simulation was based on kinematics parameters of robot. The article is the introduction to further work on the use of the Mechatronics module to perform the most real simulation of the Fanuc ARC Mate 100iB industrial robot.
Determination of material constants for high strain rate constitutive model of high entropy alloys
Authors: Matache L C , Lixandru P , Chereches T , Mazuru A , Chereches D , Geanta V , Voiculescu I , Trana E , Rotariu A N
Published: August 2019

The paper deals with constitutive models determination for a group of high entropy materials (coded Bl-x). The procedure includes the following steps: experimental determination of mechanical characteristics for quasi-static domain through compression tests, correction of experimental data of quasi-static tests using numerical simulation, acquisition of experimental data obtained on the Split Hopkinson Pressure Bars and their simulated interpretation. Using the processed data, the constitutive patterns of the materials under investigation are drawn. The experimental data correction for quasi-static tests performed using numerical simulation involves drawing the engineering stress/strain diagram, the transition to the plastic characteristic diagram in the hypothesis of perfectly cylindrical shape of the specimen throughout the test, simulation of the compression deformation process in the presence of friction force on the end specimen surfaces and the correction of the characteristic plastic diagram using the calculated error. Dynamic data obtained on Split Hopkinson Pressure Bar were interpreted using a methodology previously published. Experimental data under real conditions are compared with data obtained by numerical simulation on an elasto-plastic model. The viscous component of the dynamic response is the difference between the real and simulated on the elasto-plastic model responses.
Determination of a methodology for formulating constituent models of high entropy alloys
Authors: Matache L C , Chereches T , Lixandru P , Mazuru A , Mitrica D , Trana E , Somoiag P , Rotariu A N
Published: August 2019

A program, based on static and dynamic regime tests and correspondent numerical simulations, was conceived to be appliedfor high entropy alloys mechanical characterization. The objective was to establish a combined experimental & numerical methodology for dynamic characterization of high entropy materials in high strain rate processes. The results of static tests were used to draw the characteristic diagrams of the real material. Based on the results obtained in the compression test, a numerical simulation was performed and a material constitutive model was determined in quasi-static conditions by an iterative process. In the formulating process of constitutive equations for high entropy materials, the dynamic experimental results obtained on SHPB were interpreted using similar simulated numerical models. The methodology conceived in this paper is applicable in materials science for the determination of the constitutive models of new materials.
The frictional contact of coated bodies. Part II – The slip-stick contact
Authors: Spinu S , Cerlinca D , Musca I
Published: August 2019

Fretting is a special wear mode that occurs in a contact subjected to minute relative motion by vibration or other perturbations. The solution of the slip-stick elastic contact is required to address the problem of tractions and stresses arising in a fretting contact. This solution may be particularly difficult to obtain for coated bodies, considering that, unlike the case of homogenous materials, the response of layered materials to unit load has not yet been expressed in closed form. However, explicit expressions, also known as the frequency response functions, have been derived in the Fourier transform domain. Considering that displacement and stress calculation in an elastic contact process yields convolution products arising from superposition of effects, the existing frequency response functions can be used to calculate the response of layered materials directly in the spectral domain, and subsequently transferred to the space domain. Once a method for elastic displacement calculation in layered materials is made available, the slip–stick elastic contact problem can be solved in the same manner as for homogenous materials. The contact problems in the normal and in the tangential direction are coupled, as opposed to the sliding contact model. The numerical solution allows for identification of the slip and stick regions, and of the corresponding contact tractions. The latter tractions can be subsequently used to assess the stress state in the coated body, and thus to formulate competent design decisions.
Statistical control of forming process
Authors: Teodor V G , Paunoiu V , Carausu C , Baroiu N , Costin G A
Published: August 2019

A qualitative product must be obtained through a stable and repeatable process. In order to control a defining characteristic of the quality of a specific product, various specific methodologies have been developed in time. One of the most known methods of this kind is the statistical control of the process which provides users with a powerful and useful range of tools designed to ensure process stability and improve capacity by reducing variability. These tools have the following great advantages: they are simple to use; are effective and can be applied to all processes. This paper presents a software application designed to conduct a forming process by the statistical control method. The program analyzes a database of measured values of the traceability characteristics and identifies whether these values have a statistically normal distribution. In the affirmative case, the main statistical indicators of the considered sample are calculated: maximum and minimum values, amplitude, average value, median, dispersion, process control limits and process capability index. These statistics are displayed both numerically and graphically. By using the software, it is possible to track the process and, if exists the tendency to overcome the control limits, to change the process parameters that caused the change in the quality characteristics.
Programming and wireless control of a wafer manipulation SCARA robot using a mobile device
Authors: Coman G C , Stan L , Ivan A M , Nicolescu A F , Verdete B
Published: August 2019

The research performed by the authors had the purpose of developing a control and programming application for a 3-axes SCARA robot designed for wafer manipulation and integrating it with a mobile device capable of wireless communication. The mobile device was then used to command axis movements, internal signals and for programming. The application was developed as a user-interface capable of communicating with robot’s controller and converting the user inputs into controller commands. In order to achieve position control, the direct kinematic model of the robot was developed. Furthermore, the application was integrated with the V-REP virtual simulation platform in order to achieve simulation and offline programming capabilities - the V-REP software provided the 3-D environment and the kinematics modelling functions required to perform the simulation while receiving commands from the developed application. Finally, a few demonstrative applications were configured in order to test the functionality of the system. The research has important implications in the field of industrial wireless communication, being a step towards more flexible robotic applications, full integration of remote operation technologies and easier access to remote production facilities.
Virtual prototyping, physical structure development and PC control of a double arm (five link) SCARA robot
Authors: Coman G C , Serban C , Ivan A M , Nicolescu A F
Published: August 2019

The research presented in this paper is linked to parallel kinematics robots, their performances evaluation and analysis of their integration opportunity at industrial level. Along this research a double arm SCARA robot (including planar parallel kinematics of a 5 links / 2 DOF mechanism) was developed. The first stage of the project consisted of robot physical structure 3D modelling. The second stage of the project was oriented towards kinematic modelling of robot’s mechanism. Next, in the third stage of the project the real robot was built, including the mechanical structure, the sensorial and electrical driving system for the planar mechanism, the pneumatic driving system for the vertical axis and the vacuum gripper. The fourth stage of the project consisted of configuring the robot controller so that it could be programmed and controlled through a PC. This implied the establishment of communication protocols between the robot’s PLC and the PC, the development of the programming & control software interface for PC robot control. Using this interface, the robot was programmed to perform a pick-and-place application. In the final stage of the project the repeatability of the robot was measured in order to evaluate the accuracy characteristics of robot’s parallel kinematic structure.
Influences of the circular economy in industrial engineering
Authors: Botezatu C , Oroian B , Hrituc A , Condrea I
Published: August 2019

Epoxy resins are some of the best-performing resins currently available on the industrial market. By adding additional filler materials (glass, porcelain), the epoxy resin acquires superior mechanic and thermal properties. The areas in which epoxy resins are used are multiple: metal coating, electronics and electrotechnics, manufacture of paints and adhesives, obtaining plastics with special properties or in construction. Epoxy paints are used indoors because they are UV-sensitive (they get the appearance of chalk) on the outside. However, they are very good as corrosion-resistant primer and very good protection against water and humidity. That is why they are used as a first layer in the automotive or shipbuilding industry. Epoxy adhesives are very resistant and are used in many areas: airplane, car, bicycle construction. Therefore, when making the frame to pour a resin, it should be taken into account that there are few materials that do not stick very well.
The impact of open innovation on product development: innovation versus creative ecosystems
Authors: Bujor A , Avasilcai S , Hutu C A , Avram E
Published: August 2019

Developed business ecosystems exhibit open innovation as the most relevant booster of organizational development. Also, from a combined approach to innovation perspective, using collaboration among different stakeholders in order to achieve competitive advantages, open innovation serves as an important technique for new business model creation. Thus, it is especially important to enhance the impact of open innovation on organisational processes as the main driver for organizational higher performance and development. Based on literature review this paper aims at exploring the main transition from product development processes to co-creation products through implementation of open innovation, in highlighting key differentiating aspects by different types of ecosystems. Consequently, a comprehensive framework for co-creation processes in innovation and creative ecosystems, in terms of product development stages, is provided based on specific adopted criteria, emphasising the open innovation impact within innovation versus creative ecosystems.
Assessment of an accident risk into an industrial building site
Authors: Cojocaru D , Solomon Gh , Dijmarescu M C
Published: August 2019

Starting from the concept that the industrial construction represents a work system with four defying components such as the executant, the workload, the means of productions and the work environment, the collective protection systems for the principal categories of activities, which are ongoing into the industrial building sites, must be analyses and evaluated. The work accidents risks and occupational illness are and they will be present all the time in the industrial building sites. The problem of prevention specialists consists in the way in which the organized and implemented measures are applied and made effective, in order to avoid the occurrence of events or, at least, to mitigate their consequences for the jobs in the industrial sites. Of the specific activities frequently encountered in temporary construction sites, the construction and assembly of metallic structures for the strength and elevation of buildings is highlighted, where there is a large and complex exposure to the risks of injury and also to professional illness. This paper presents a complex evaluation of accidents risks in a construction site for a mechanical locksmith stationary metal structures.
Device for the study of the friction coefficient in the bolt-chain link joint
Authors: Gavrila C C , Lates M T
Published: August 2019

The friction which appears in chain drives has an importantinfluence on their dynamic behaviour, wear and lifetime. The most significant friction and also wear is given by the bolt and chain link joint; in most of the cases this led to changes of the chain geometry and failures. Due to this, the study of the friction in the chain joints is required, but also difficult because of some particularities, as bolt and chain link reduced dimension, the oscillate motion in joint, chain link load.The paper presents a device for the friction coefficient study in the chain link-bolt joint, according to the mentioned requirements. First, the device ensemble 3D model is presented; the geometrical and kinematical restrictions between the parts are also defined. Then, the finite element analysis on this model is realized and is achieved for different initial conditions. In the paper final part, the analysis results and conclusions are presented.
Lean Learning Factory at the University of Pitesti
Authors: Nitu E L , Gavriluta A C
Published: August 2019

Today, the globalization of production and strong competition in the automotive industry requires manufacturers to offer their customers a wide range of products of the best quality and at lower prices. In order to accomplish this objective, the production systems must be as flexible and responsive to customer requests as possible and the production flow should be uniform. The usage of the most modern methods, techniques and tools, such as modelling and simulating production flows and Lean manufacturing, in the layout planning, work organization and production management is imperative to such production systems. In this context, at the University of Pitesti, a Learning Factory has been in development, that facilitates the research in laboratory conditions of modern manufacturing methods and their transfer to factories from automotive industry. The laboratory was developed within a research project and includes integrated research and teaching platforms, specific to layout design, modelling and simulation flows and Lean manufacturing, while also comprising elements of digitalization (Industry 4.0). The Lean Learning Factory at the University of Pitesti is in a continuous developing process which will allow students to enrich their practical skills and competencies concerning modern methods, techniques and tools, by using factory-like equipment. Moreover, this laboratory can also be accessed by automotive companies’ employees from Arges County to improve their abilities in Lean manufacturing.
A methodology for intelligent monitoring the vibrations of an asynchronous motor
Authors: Popa V , Popa L
Published: August 2019

This paper presents an intelligent methodology for diagnosing incipient defects of rotating machines and is focused on monitoring the vibrations of an asynchronous motor. Monitoring of industrial plant operation parameters requires the acquisition of many electrical and non-electric parameters, parameters that can be monitored with powerful software. The technical state of operation of an industrial machine can be judged based on the symptoms it exhibits during operation, in our case the vibrations. Vibration analysis that occurs during engine operation may indicate electrical defects, such as broken rotor blades, unbalanced stator circuits, eccentric rotors and stators, loose power connections. There are mechanical defects and electrical faults in the vibration spectrum. A web application has been created to facilitate the interpretation of the linear spectrum resulting from the vibration monitoring of an asynchronous motor and to be accessible to any user. There was developed an application with Microsoft Silverlight, a software platform that allows us to display advanced multimedia content from a web browser. The spectrum reproduced by the application is simple, precisely to be accessible to everyone and to know very easily whether the machine is working correctly or not.
URANSE simulation for the Seakeeping of the KVLCC2 Ship Model in Short and Long Regular Head Waves
Authors: Bekhit A , Lungu A
Published: August 2019

In the present study, the vertical motions and the added resistance in waves of the KVLCC2 ship model are predicted numerically in regular head wave, for a single wave height and different wave lengths, including long and short waves. The numerical simulation is performed by making use of the ISIS-CFD solver of the commercial software FineTM/Marine provided by NUMECA, where the discretization in space is based on finite volume method using unstructured grid. The unsteady RANSE are numerically solved, while the turbulence is modelled by making use of the k-ω SST model. The free-surface is captured through an air-water interface based on the Volume of Fluid method. For validation purposes, the computed solutions are compared with the available tank test data existing in the public domain. A systematic grid convergence study based on Richardson Extrapolation method is performed for a single wave case on three different grid resolutions, as an attempt of predicting the uncertainties in the numerical solution. A thorough investigation for the free-surface topology at different encountering moments is also presented to prove not only the accuracy of the solver, but also its robustness.
Barge’s study under impact loads
Authors: Nechita M , Mocanu C I
Published: August 2019

The aim of this paper is to present a method of increasing the safety of inner water navigation. It concern on improving the structural resistance of a barge during design process. Numerical structural analyses of the deck and the board are purposed to solve the problem. Different values of friction coefficient steel on steel are considered as input data. Naval structure’s behaviour is analysed using the area and the volume values of the struck surfaces. The post-processing of data shows an influence of the friction coefficient on Von Misses stress of the deck’s structural components. This method also allows evaluation of the barge damages.
Improving the hydrodynamics performance of the catamaran passenger
Authors: Pacuraru F , Mandru A
Published: August 2019

Interest in medium and high-speed marine transportation has acquired a wide variety of research on catamaran hydrodynamics. The demand for high-speed small ship has increased in last period, especially for the passenger ferry boat. The paper considers the assessment of the free surface flow around the hull of the catamaran passenger ship in order to improve its hydrodynamics performance. To accomplish the objective, Computational Fluid Dynamics based on RANS-VOF solver have been used. The free surface treatment is multi-phase flow approach, incompressible and non-miscible flow phases are modelled through the use of conservation equations for each volume fraction of phase. To evaluate the effect of the central bulb positioned between the hull bodies on the ship resistance, nine different sets simulations were carried out for eleven speeds corresponding to Froude numbers between 0.12 and 0.80. Nine different configurations of the bulb considering three different depth and three position along the hull (bow, midship and stern) have been considered. The calculations revealed that wave resistance can be reduced by using a central bulb between the catamaran hulls by up to 8%. This happens when the bulb is positioned at the bow and the stern and for Froude numbers 0.3-0.6.
High-order calculation of triboelectric charge density using a transition matrix element in a triboelectric nanogenerator system
Authors: Kim SeongMin
Published: August 2019

The second-order calculation for triboelectric charge density (σ
tribo) between a metal and polymer is performed analytically based on the molecular-ion-state model. The transition matrix element ∣MAB∣ is approximately calculated for two cases where the distance between metal and polymer is very small (d ≪ 1) and the electronic energy is near the Fermi energy level (EF) because electron transfer between metal and polymer is dominant at this level. The σ
tribo approaches zero-order approximation as d approaches zero. Thus, although d is very small (d ≪ 1), its effect as a second-order approximation, such as dielectric constant and dielectric thickness, is shown here.
The Strengthening of Laboratory Systems in the Meningitis Belt to Improve Meningitis Surveillance, 2008–2018: A Partners’ Perspective
Authors: Feagins Alicia R , Vuong Jeni , Fernandez Katya , Njanpop-Lafourcade Berthe M , Mwenda Jason M , Sanogo Yibayiri Osee , Paye Mariétou F , Payamps Sarah K , Mayer Leonard , Wang Xin
Published: August 2019

Laboratories play critical roles in bacterial meningitis disease surveillance in the African meningitis belt, where the highest global burden of meningitis exists. Reinforcement of laboratory capacity ensures rapid detection of meningitis cases and outbreaks and a public health response that is timely, specific, and appropriate. Since 2008, joint efforts to strengthen laboratory capacity by multiple partners, including MenAfriNet, beginning in 2014, have been made in countries within and beyond the meningitis belt. Over the course of 10 years, national reference laboratories were supported in 5 strategically targeted areas: specimen transport systems, laboratory procurement systems, laboratory diagnosis, quality management, and laboratory workforce with substantial gains made in each of these areas. To support the initiative to eliminate meningitis by 2030, continued efforts are needed to strengthen laboratory systems.
Epigenetic aspects of floral homeotic genes in relation to sexual dimorphism in the dioecious plant Mercurialis annua
Authors: Khadka Janardan , Yadav Narendra Singh , Guy Micha , Grafi Gideon , Golan-Goldhirsh Avi
Published: August 2019

Sex-determination in Mercurialis annua is not related to chromatin conformation or DNA methylation of floral homeotic genes but might be regulated upstream of these genes by one or more unknown gender-specific factors that affect hormonal homeostasis.
Dynamic modulation of theta–gamma coupling during rapid eye movement sleep
Authors: Bandarabadi Mojtaba , Boyce Richard , Gutierrez Herrera Carolina , Bassetti Claudio L , Williams Sylvain , Schindler Kaspar , Adamantidis Antoine
Published: August 2019

Theta phase modulates gamma amplitude in hippocampal networks during spatial navigation and rapid eye movement (REM) sleep. This cross-frequency coupling has been linked to working memory and spatial memory consolidation; however, its spatial and temporal dynamics remains unclear. Here, we first investigate the dynamics of theta–gamma interactions using multiple frequency and temporal scales in simultaneous recordings from hippocampal CA3, CA1, subiculum, and parietal cortex in freely moving mice. We found that theta phase dynamically modulates distinct gamma bands during REM sleep. Interestingly, we further show that theta–gamma coupling switches between recorded brain structures during REM sleep and progressively increases over a single REM sleep episode. Finally, we show that optogenetic silencing of septohippocampal GABAergic projections significantly impedes both theta–gamma coupling and theta phase coherence. Collectively, our study shows that phase-space (i.e. cross-frequency coupling) coding of information during REM sleep is orchestrated across time and space consistent with region-specific processing of information during REM sleep including learning and memory.