bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of resistance butt welding thermal cycle on structure and properties of termomechanically rolled steel
Authors: Górka J , Jamrozik W , Wyględacz B 
Published: September 2020

Abstract
In this article examination of structure and properties of resistance butt welded joints from S700MC high strength steel. 10 mm thick including recording welding thermal cycle recording are presented. The thermal cycle acquisition was performed on purpose build rig with a thermographic camera and a computer. The thermal fields acquisition station consisted of Varocam Head HR thermal camera and computer with Ibris 3 plus software, which enabled control of thermal camera parameters and saving of acquired on a local storage media. Aside from environmental parameters, such as temperature and humidity of surrounding, transmissivity of atmosphere equal to 1 and mean emissivity of steel surface of 0.9 were set. Noticeable impact of welding thermal cycle on strength and plastic properties was observed.
The analysis of high-pressure water jet cutting of thick aluminium alloy 6061-T651 from a statistical perspective
Authors: Grigoraș C C , Chiriță B , Brabie G , Zichil V , Herghelegiu E , Tâmpu C , Ciofu C , Iancu C 
Published: September 2020

Abstract
The main context in which abrasive water cutting is used is the reduction of thermal deformation induced by thermal (plasma arc PAC, oxyfuel OFC, laser) of electrothermal (electroerosion EDM) cutting methods. Although it is not the cheapest or time-efficient technique it can be used on a wide variety of metallic and non-metallic materials. Among other benefits are the lack of burrs, high precision and improved surface finish, low setup time and stress-free cutting. This leads to no secondary processing required in many other applications. Depending on the material hardness the cutting thickness can reach up to 300 [mm]. The present study proposes an analysis of high-pressure abrasive water jet cutting of a 19 [mm] thick plate. The aluminium alloy used in this study was Al-6061-T651. This alloy is being used especially in the aeronautics industry due to is excellent welding properties. The experiments were conducted using multiple input and output factors. The design of experiments (DOE) takes into account input factors and offers models for responses. The study was organised according to response surface methodology, with an I-optimal design type and a quadratic design model. The input factors were: cutting pressure, standoff distance, programmed quality of the cut. The responses analysed were: entrance (Iw) and exit (Ow) width of cut, and taper angle (α). An ANOVA analysis was performed for each response. This interpretation implies the significance (p-value) that the input factors have on the variation of the responses. For Iw and Ow a reduced 2FI model was proposed, while for θ a linear model was suggested. The p-value obtained for each response is smaller than 0.0001, which classifies the models as significant. The ANOVA fit statistics determine the R-squared error between 0.964 and 0.995, meaning that the responses are well defined by the input value variations. This high confidence in the results leads to accurate mathematical models.
Design of reinforced composite material to overcome wear occurrence in transportation pipes
Authors: Ibrahim A J , Salih A L M , Al-Maliki S J B , Al-Baali G 
Published: September 2020

Abstract
The wear of carbon steel piping systems has been one of the major problems for various industries that involve the high-speed transportation of their raw materials and/or products. Transportation of cement in construction materials manufacturing factories through carbon steel pipes was studied to suggest a resistible material of unsaturated polyester reinforced with glass fiber and the aluminum honeycomb to be used instead of these pipes. A laboratory-scale apparatus was built to examine the wearing in pipes for the carbon steel and composites specimens. The electrical and mechanical prosperities of the composites were studied by using the ASTM standards to find the best conditions for the newly constructed pipes. It was found that, by increasing the concentration of aluminum powder up to 50 wt% of the composite mixture, the electrical conductivity was increased to be within the range of semi-conductance but the mechanical properties decreased. The best concentration of aluminum powder was found to be 30 wt% of the composite mixture, which represents the most suitable electrical and mechanical properties. Also, it was found that the samples of aluminum honeycomb were gained very good electrical conductivity with special mechanical properties that are suitable for many practical applications.
Lean Manufacturing 4.0 - dynamic physical and cybernetic system for Industry 4.0
Authors: Ionel D-S , Opran C Gh , Vălimareanu B C 
Published: September 2020

Abstract
The intelligent manufacturing system is realized through fusion between the production system with information and communication technologies. This allows to build a digital twin of physical production system, the two being connected and communicate each other data in real time about production status and progress. The existing Industry 4.0 physical system identify the active production resources, who are directly involved in the production processes, and of the passive ones, who have supporting roles. In Industry 4.0 those resources are directly interconnected with the corresponding cyber elements in order to supervise the whole system and the corresponding processes. Into this architecture, the physical production passive and active resources will form a dynamic subsystem, through which one can manage the physical and cybernetic changeable manufacturing processes and various products, in different manufacturing stages. This paper presents a solution to change the cyber-physical system by replacing the production physical active elements with those elements who need to change on the production line and the corresponding digital resources, including the specific Lean 4.0 production system tools who supervises the manufacturing cell and controls the execution. This dynamic system allows achieving a higher level of the production system.
Optimal management of production processes using the function of losses in the production processes
Authors: Kirov K , Avramova T 
Published: September 2020

Abstract
In today’s modern world the manufacturing processes are designed in such a way as to ensure the desired quality of the end product. In this article are considered some aspects of desired quality in performance. The described quality management tools are based on Taguchi’s theory Quality Engineering and Robust Engineering. In relation to this in the paper are presented a new application for assessing the losses of society from the irrational use of resources or their harmful impact in the transformation into a production process, the possibilities of Taguchi’s theory in assessing the losses of the stakeholders in the functioning of the enterprise - in case of ineffective or inefficient use of the production process and proposal of the possibility for a complex assessment of the losses of the society and the stakeholders from the production of products and operation of production processes at quality indicators different from the desired nominal values
Experimental study on catamaran hydrodynamics
Authors: Mandru A , Pacuraru F 
Published: September 2020

Abstract
In the last decade, the main concerns of the maritime industry are the reduction of fuel and carbon emissions. IMO (International Maritime Organization) has introduced relevant conventions and improvements in fuel economy standards for ships. Thus, different research projects have been developed to improve the energy efficiency of ships, reducing fuel consumption and carbon dioxide emissions. The flow around the catamarans is a complex hydrodynamic phenomenon due to the interference effects that occur on the free surface between the bodies of the catamaran. The flow around the ship hull has a wide variety of physical fenomena, many of which are relevant for the study of resistance. The two important aspects of the interference effects associated with the catamarans with direct influence on the hydrodynamic performances are: the viscous interference due to the asymmetric flow around the bodies with direct effect on the development of the boundary layer and the wave interference generated at the free surface from the interactions between the wave systems generated by each hull.
First set of towing tank tests have been performed to evaluate the ship resistance of the catamaran hull, interference between wave system of the hulls and to analyse the hydrodynamic parameters of the flow. To evaluate the effect of the central bulb positioned between the hull bodies on the ship resistance, six different sets of experiments were carried out for seven speeds corresponding to Froude numbers between 0.20 and 0.80. Six different configurations of the bulb considering three different depth and two position along the hull (bow and stern) have been considered. The calculations revealed that residual resistance can be reduced by using a central bulb between the catamaran hulls by up to 10%. This happens when the bulb is positioned at the bow and the stern and for Froude numbers 0.4-0.6.
Modelling of maritime ship repairs processes in shipyards, using the linear regression and correlation theory
Authors: Manea M G , Zăgan R , Manea E 
Published: September 2020

Abstract
The tendering and programming-planning activities carried out in the shipyards for the execution of the repair works of the maritime vessels are the result of estimates that operate with fixed data, conditioned by variables belonging to a wide spectrum of conditions and limitations. In the documentation made for the elaboration of the present work and the resolution of the chosen research topic, the studies were directed to the fundamental theoretical fields of: probabilities and statistics; modelling and numerical simulations. The objective assumed by the authors was to find a well-founded method for estimating the retention period of the ship in the shipyard, to exploit the information held in the portfolio of repair works performed to various clients, over time. This gives the perspective of optimizing the decisions of the shipyard management with reference to the problem of anticipating and programming the duration of the repair works of the maritime vessels. The purpose of the research consists in proposing an analytical function for analyzing the linear dependence of the time period, as a dependent variable, on the works carried out in the shipyard, considered as independent variables. The role and importance of the technical specification of the works prepared by the owner / technical manager of the ship, from the perspective of the management of the repair works of the maritime vessels in a repair yard, are highlighted, as well as the importance of the selection of variables with significant influence in the forecast of the duration of the repair works of the maritime vessels in a shipyard.
Micro gas turbine combustion chamber CFD modelling
Authors: Mangra A C 
Published: September 2020

Abstract
The interest in micro gas turbines has been steadily increasing. As a result, the researchers’ attention has been focused on obtaining optimal configurations for micro gas turbines depending on the applications in which they are used. Micro gas turbines are suitable for both civil and military applications. Presently, they are often used in the development of Unmanned Air Vehicles (UAVs). Micro gas turbines have the following advantages: a wider range of options regarding the used fuel and a significant system weight reduction. This paper presents the CFD modelling results regarding an annular type combustion chamber. This combustion chamber is part of a 80 daN micro gas turbine, destined to equip a small scale multifunctional airplane. The combustion chamber is equipped with eight pressure-swirl injectors, using Jet-A as fuel. A 3D RANS numerical integration of the Navier-Stokes equations has been carried out, using an Eddy Dissipation combustion Model (EDM) and the k-ε turbulence model, implemented in a numerical simulation conducted using the commercial software ANSYS CFX. An unstructured computational grid, generated using ICEM CFD, has been used. The fuel is injected directly in the fire tube in the form of droplets. The initial fuel droplet’s diameter has been considered to be 50µm and the fuel spraying cone angle has been set at 90°. The fuel droplet break-up and evaporation processes have been simulated using numerical models available in ANSYS CFX library. A two steps reaction mechanism, which takes into consideration the formation of NO, has been used. The results thus obtained are encouraging. The flame developed in the central area of the fire tube, its walls thus not being subjected to high temperatures. Also, the maximum temperatures were obtained in the primary zone of the fire tube. The temperature then decreased in the fire tube’s secondary zone and dilution zone, until it reached an average value of 1200 K at the combustion chamber exit. Regarding the pressure, based on the numerical simulation results, a 5% pressure loss has been obtained. The numerical results will be validated by conducting combustion tests on a testing rig which will be developed inside the institute’s Combustion Chamber Laboratory.
Dynamic modelling of overhead crane
Authors: Muscă (Anghelache) G. D. , Năstac S. 
Published: September 2020

Abstract
This paperwork deals with dynamics of overhead crane. Dynamically speaking, I considered the overhead crane beams as continuous medium with distributed elasticity and weight, simple supported at ends, stressed by distributed as well as focused forces. The distributed forces are the own weight and forces of inertia (mass forces) and focused forces are those produced by the carriage and transported load. Focused forces may travel along the overhead crane, so they have variable position and are, in their turn, variable in time as the carriage, always considered in contact with overhead crane, is, on one hand subject to the same accelerations as the beams oscillate in vertical plane in the place where the carriage is at the said moment, and produce variable inertia forces, and, on the other hand, a load is hanging on it, sustained by elastic cables, pulling down with a variable force, depending on how oscillations of the load and overhead crane beam mix up together. The overhead crane is a beam with variable profile subject to static and dynamic, focused and distributed loads. This makes the mathematic model of the overhead crane dynamics to be very complicated and the presentation that follows shall prove it. Analysing the results presented in this study it may come to the conclusion that monitoring and analyse of overhead crane dynamics is extremely important because it may highlight the potentially dangerous situations in operation of this equipment.
A Thermal Analysis in Solidworks for the MQL Systems of the Metal Cutting Processes
Authors: Olaru I , Olaru C 
Published: September 2020

Abstract
Through the cutting operations of the different metallic materials, large cutting forces are developed, they depend on the material to be processed and on the cutting parameters. During the cutting operation, due to the friction between the tool and the material to be processed, an important amount of heat is released. As the friction between the elements is higher, the heat generated by the attachment can disturb the cutting process. If the temperature from the cutting process is higher than a certain value, the resulting surfaces may have a number of processing defects. In order to reduce the temperature value of the cutting process, different cooling systems have been developed over time that use a wide range of cooling liquids. Cooling liquids have a number of advantages and disadvantages, after the cutting process they have to be discharged and their negative influence on the environment to be minimal. Recent studies have attempted to reduce this amount of coolant by streamlining fluid flows. Systems that use minimal amount of lubricant or coolant are MQL (Minimum Quantity Lubrication) type. These systems have special nozzles so as to obtain the best possible distribution of the coolant in the cutting area, as well as a good mixing if different cooling liquids are used. This paper aims to study the cooling systems for the cutting processes, forms of nozzles to send the fluid in the working area, thereby thermal analysis, from the desire to use an efficient MQL system.
Indoor air quality monitoring universal device
Authors: Panaitescu M , Dumitrescu M V , Panaitescu F V 
Published: September 2020

Abstract
This paper presents a solution for indoor air quality monitoring universal device. Existing devices on the market analyze a small number of indoor air quality parameters, require expensive consumables and periodic maintenance services. Our solution has a small volume, portable, easy to use, low price, almost non-existent maintenance, possibility monitoring a wide range of compounds and harmful elements of air. The proposed device can be equipped with a wide variety of sensors: gas sensor, digital gas sensor for air quality breakout, combined temperature and barometric pressure sensor, a 3 sensor device suitable for gas leak detection air quality monitoring. The results obtained with this device are: the individual values for each monitored element, local and online visualization of the data, the alarms for exceeding values, online access to data for analysis and processing. Finally, the solution proposed by us is cheap, we can work continuously, with the mention that if defects occur they can be remedied quickly by replacing the parts with replacement ones, without requiring periods of interruptions in the monitoring process.
An innovative class of aluminum alloys for automotive industry: investigation on their corrosion resistance
Authors: Peter I , Castella C , Molina R 
Published: September 2020

Abstract
Self-hardening aluminum alloys (AlZn10Si8Mg, EN-AC-71100) represent an interesting innovative class of material for the production of automotive and aerospace components with high-mechanical strength and good corrosion resistance. The aim of the present is related to the investigation of the intergranular corrosion resistance of an innovative class of self hardening alloys. Microstructural characterization combined with compositional analysis has been carried out by Optical and Scanning Electron Microscope equipped with Energy X-rays Dispersive Spectroscopy unit. Three-point bending test and Charpy Impact test have been performed and the corrosion resistance of the alloys has been investigated according to standard BS 11846, method B. The susceptibility of the alloy to intergranular corrosion has been assessed evaluating the maximum corrosion depth and the weight loss of the alloy after corrosion test. The results obtained have been demonstrated that the corrosion resistance of the alloy can be achieved by Mg addition.
Liquid Wood Rheology
Authors: Petrescu T C , Bărhălescu M L , Ibănescu C , Danu M , Văideanu D , Costescu E Puiu 
Published: September 2020

Abstract
“Liquid wood” is a biopolymer composite exhibiting a lignin matrix. Lignin is separated as a by-product of paper. Following research by German scientists from a production company, an invention was made that determines a new use of lignin, the capitalization of said product in this case being superior. This material combines lignin with other natural substances: resins, waxes, vegetable fibres etc. It results a polymer that exhibits certain physic-chemical properties which recommend it for large scale use, being able to substitute plastic materials. Some of the properties of “liquid wood” are: it is a thermo-injectable polymer, it is obtained from renewable resources and it is biodegradable. Existing injection or extruding machines, used for synthetic polymers such as polyethylene and polypropylene, can be employed to obtain various “liquid wood” parts. It has been observed that injection process parameters influence mechanical and physic – chemical properties of products obtained from “liquid wood”. In order to find the optimal injection parameters for an object that exhibits certain mechanical and physic – chemical properties, it is necessary to determine the rheological properties of “liquid wood”. In this paper, several “liquid wood” rheological properties have been determined, in order to assist the optimization of the injection process.
Numerical Analysis of the Thermal Performance in Traditional and Developed Shapes of Thermosyphon
Authors: Qasim M S , Freegah B , Ali G S 
Published: September 2020

Abstract
In recent years, the research in renewable energy is remarkably increased to reduce the reliance on fossil fuels. Solar energy took the lead among the other sources of renewable energy due to its availability everywhere and the feasibility of its use for various circumstances. Thermosyphon is one of the most successful systems for solar energy conversion. In the present study, a CFD code is employed to analyze the natural convection phenomenon which is inherent in the performance of a thermosyphon system. A steal pipe of 25 mm internal diameter and 1250 mm length is considered as the condenser of the thermosyphon. Water jacket is used to cool the condenser with an internal diameter that is five times that of the condenser. Two types of pipes are considered in the present study, namely; straight and helical pipes. The case of helical pipe assumes five different numbers to turns, which are; 10, 20, 30, 40 and 45 turns. A solar heat flux of 500 W/m2 and above is used in the analysis. The results obtained from the numerical analysis showed that the helical pipe is more efficient than the straight pipe in heating the water inside the condenser jacket for the same operating conditions. The ratios of increase in jacket water temperature of the five cases of the helical pipe to that of the straight pipe were 23.8%, 36.5%, 42.1%, 45.3% and 46.2%, respectively.
An Analysis on some thermal characteristics of AlMg10-SiC ultralight composite materials
Authors: Rusu O , Rusu I 
Published: September 2020

Abstract
The paper presents the determination of the specific heat, thermal conductivity and thermal expansion coefficients of some composites of the type AlMg10-SiC with the help of a differential scanning calorimeter. For the experiment we will use several types of composites with different concentrations of SiC (5%, 10%, 15%, with 120 micrometres medium size).One sample category was obtained by melt bubbling method (A) and the other one by soluble salt method (B). We obtained cellular composites using A method and porous composites using B method. The paper presents by comparison the thermal properties of the two categories of materials. The paper also presents the equipment used, as well as its operation. We used a differential scanning calorimeter for the specific heat and thermal conductivity determinations and thermomechanical analyser equipment for linear expansion coefficients. Based on the values obtained for the thermal characteristics of the investigated composite materials, those directions of applications can be suggested, which can be based on the absorption characteristics of the deformation energy of these composites, even at temperatures above 100°C, a situation for which, for example, in general, polymeric composites cannot be used.