bluuebunny/crossref_metadata_2025 huggingface dataset:
Medical Waste as a Source of Antibiotic Contamination in Wastewater
Authors: Timofeeva S S , Bodienkova G M
Published: October 2021

In modern conditions of the coronavirus pandemic, the amount of medical waste is sharply increasing, among which antibiotics that enter the environment from various sources are among the most hazardous from an environmental point of view. The article analyzes the sources of antibiotics coming with hospital wastewater. The majority of medical institutions for the population of our region have no local treatment facilities and antibiotics transit through them. The aim of this paper was to collect and analyze information on medical waste in medical institutions of the Baikal region as a source of antibiotics in water bodies and to assess environmental risks. Based on information on the procurement of antibiotics for medical institutions in the Irkutsk Region, it was established that the sources of pollution of natural waters with antibiotics are wastewater from agricultural enterprises, medical institutions, and home first-aid kits. The total amount of antibiotics circulating in the Irkutsk Region reaches 9.2 tons, the residual concentration of antibiotics in wastewater from various sources ranges from 0.3 to 3.9 mg/L. The hazard quotients for drinking water contaminated with antibiotics are of medium and low categories.
Analysis of heat losses during heat supply of an urban-type settlement using a heat pump
Authors: Nikitin A A , Konicheva O E , Muraveinikov S S , Nezhurin E V , Rachkovsky N O
Published: October 2021

Centralized heat supply systems include a network of pipelines connecting buildings and structures in such a way that entire districts and quarters are supplied with a heat carrier from a single boiler plant. District heating is a well-studied part of the energy system. Despite this, low temperature district heating is still underdeveloped, although it is one of the key technologies for energy efficient urban heating. Low-temperature heat supply systems are the basis of 4th generation district heating systems, since they can significantly reduce heat losses during transportation of the heat carrier to the heat energy consumer and allow the use of heat from renewable sources, for example, heat pumps. The study focuses on analyzing the heat loss of a district heating system by comparing simulation results at a standard flow temperature and at a temperature typical of the 4th generation heat supply schedule. On the basis of the created model, the calculation of heat and hydraulic losses of the low-temperature district heating system was carried out, as well as a comparative analysis in comparison with the standard heat supply system.
Reorganization of industrial territories in the context of urban development
Authors: Taubert E A , Pavlova A S
Published: October 2021

The area of Saint Petersburg is about 144,000 hectares, industrial areas occupy 24% of urban lands. The historical center of the city is surrounded by the so-called “gray belt”, which is a zone of industrial enterprises that are unsuitable for further use for their intended purpose and that have come to an emergency condition. It was formed in the following way: enterprises were moved to the outskirts of the city, and when the development of the residential zone within the “belt” became impossible, urban development continued beyond its borders. This type of industrial development is typical of most large cities over 200 years old. Many foreign cities and towns of Russia, to varying degrees, have faced the problem of reorganizing such territories. St. Petersburg continues to develop and accept new residents, but it needs an urgent transition from extensive growth to building a model of sustainable urbanization and improving the quality of infrastructure.The purpose of this work is to provide research results that consider the effectiveness of methods for reorganizing industrial areas in urban development by the example of one of the buildings of the “gray belt”. The research object is located on the territory of a residential area under construction.The results of the project showed the effectiveness of greening the roof and facade of the building in order to increase its energy efficiency, reduce water consumption and compensate for insufficient gardening at home (this problem is especially relevant for the central districts of the city).
Subcritical processing of raw materials for the production of food additives
Authors: Zh Iskakov I , Ya Kucherenko V , Alekseev G V , Kravtcova E V , Egorova O A
Published: October 2021

The article is devoted to the analysis of pectin diffusion extraction in the extraction process from plant raw materials in a solid-liquid system. The molecular diffusion process from the inside of the extractable substance particles to their outer surface is considered as the limiting stage. The aim of this work is to study the possibility of creating an efficient production of pectin from agricultural products by carrying out a more complete extraction using a period of mass isolation in the extraction process. As it is generally recognized all over the world, the rational use of natural resources is the dominant trend in the development of the economy, which assumes the fullest use of vegetable raw materials consumed by humans in the processing. To implement such approaches, a mathematical model of the discrete diffusion process in porous diffusionally isotropic particles has been developed. A conclusion is made about the effect of mass isolation on the extraction rate for a regular mode, while the regularities of the process remain unchanged.
The control of Industrial emission via the subsoil green filters
Authors: Al-Maliki S J B , Jaafar K , Wahab B I
Published: October 2021

The vast consumption of fossil fuel as an energy source for the various industrial, commercial and municipal activities, has led to the production of huge air pollutants, in a manner that needs more modern and effective efforts and technologies to prevent their hazardous consequences. This project aims to the use of the subsoil of nearby grounds as a natural filter to distribute these pollutants based on the soil`s high porosity and their ability to handle huge amounts of the gaseous effluents of the artificial projects. Soil properties such as the mechanical properties, porosity and ground water content were tested for different depths for two types of soils, in order to assess their readiness for the tentative use as a gaseous filter and to avoid the possible negative effects for the injection of gaseous pollutants on their biologic systems. An experimental system was made using a 5 KVA power generator, the gaseous emissions of which would be distributed through the subsoil via a buried pipe. The project also, included the precautions for the possible machine backpressure that may damage it. The wet clay type of soil has shown remarkable better performance than the dry sand type.
Study on the behavior of benchmark container ships in regular waves
Authors: Chirosca A-M , Rusu L , Pacuraru F
Published: October 2021

The study of the behaviour of ships in the real sea has become a real challenge in recent years due to climate change, especially in the European sea basin. One of the main categories of types of ships that cross these waters are transport ships. The development of the economy and trade have a major influence on this type of ships, which must be studied and improved in order to be fully exploited. Investigating the ship’s behavior is not a new topic, but the changing environment of the transport ship’s specifications requires continuous study. An alternative to model testing is the use of numerical simulation through which performance can be fully evaluated using only computers, without the need to produce a scale model for testing. Due to improved computer performance, but also the disadvantages of towing testing, numerical simulations have become increasingly popular for determining ship characteristics. The shorter time in which results can be obtained, as well as the ease of controlling and changing the input parameters, contributes to the preference to use numerical simulations, to the detriment of basin tests. In this paper, the behavior of a Post-Panamax benchmark container ship in regular waves was studied. Numerical simulations were performed using SHIPFLOW MOTIONS, a solver that treats potential nonlinear flows for regular waves and provides accurate results by the free surface potential flow panel method. For our case, the simulations were performed for a range of six speeds corresponding to Froude numbers ranged between 0.174 and 0.218, for five nondimensional wavelengths (λ/Lpp) and for four wave heights. Because body discretization is one of the main factors for obtaining accurate results, an additional study was conducted in calm waters on body refinement and the influence that the mesh has on results, for a range of ten grids with different densities.
Analysis of robotic welding possibilities of a car chassis assembly
Authors: Coman M N , Rontescu C , Bogatu A M , Cicic D T
Published: October 2021

The continuous increase of the requirements regarding the quality of the welded joints (elimination of the influence of the human factor) but also the increase of the productivity of the technological processes imposed the analysis of the possibilities of implementing robotic welding processes. The introduction of robotic production lines is an increasingly common thing in the automotive industry. This paper presents the stages necessary for the realization in welded construction of a crossbeam, part of the chassis of a car. The elaborated welding technology aimed to achieve the transition from semi-mechanized welding of the assembly to robotic welding using the MAG (Metal Activ Gas) welding process. The basic material from which the crossbar is made is S355 MC steel, steel for constructions with high mechanical properties. For the robotic welding of the assembly, the design of the device necessary for the orientation and fixing of the components was made. The welding technology developed was validated by performing standard samples that were subjected to visual examination and penetrant testing but also to destructive examinations which consisted in measuring the hardness in the characteristic points of the welding bead and also by measuring its geometric characteristics. Following the analysis of the initial dimensional values obtained, it resulted that the incorrect positioning of the welding head in relation to the welded components led to the appearance of geometric defects of the welding seams, although the technological parameters of the welding regime were appropriate. After making adjustments on the position of the welding head, accepted characteristics were obtained which led to the decision to validate the welding technology used.
The nonlinear ship rolling and safe basin erosion in stochastic beam seas
Authors: Deleanu D , Dumitrache C L
Published: October 2021

A short number of steep breaking waves hitting a ship from the side may affect its dynamic behaviour and determine extreme roll angles and, eventually, capsizing. Even the capsize is a rare event, its consequences for the ship and crew are often fatal. Generally, the ship rolling in regular or stochastic beam seas could be described by a second-order non-linear differential equation with the roll angle as dependent variable. Non-linearity comes from the restoring and damping moments, which are usually represented by polynomials of roll angle or of its time derivative. In the paper, we used such a model equation to estimate the ship rolling and capsizing in a stochastic beam sea. The sea action was simulated by a harmonic function with random frequency and phase. The roll equation was solved using a simple, fast and accurate iterative scheme based on Taylor expansion which proved to be very competitive in terms of accuracy with more elaborate methods and which allowed a substantial reduction of the CPU time. Due to these properties of the scheme, we were able to conduct an extensive investigation on fractal erosion of safe basins and to represent the boundaries between capsizing and non-capsizing regions in wave frequency – wave amplitude plane and normalized integrity curves for different combinations of random wave parameters. The restoring and damping coefficients corresponded to a vehicle ferry model, considered to be either with or without bilge keels.
Study on the behaviour and comfort of reusable knitting suits of wool blends in the context of the Covid 19 pandemic
Authors: Dochia M , Kaminszky R , Fogorasi M S , Farima D , Barbu I , Nicolaescu C , Pustianu M , Popa A , Bucevschi A
Published: October 2021

Nowadays, humanity is facing serious challenges due to the disruption of the COVID-19 pandemic, affecting dramatically our healthcare system along with the economic structure, social and cultural life. Healthcare personnel treating patients with infections like COVID-19 are exposed themselves to infection. Therefore, it is compulsory to be protected from contaminated body fluids using personal protective equipment (PPE). This equipment made of synthetic fibers proved to be uncomfortable. Therefore, we developed a reusable suit composed of a blend of wool and silk to be wear under full-body protective clothing aiming to improve their comfort and safety. Firstly, we focused on the analysis of some dimensional characteristics: specific mass, porosity, thickness followed by comfort characteristics of knitted fabrics. Accordingly, the test methods comprise measurements for hydrophilic properties, air and water vapour permeability, thermal conductivity and dimensional stability to repetitive washing. After material analysis, a significant number of two-piece suits composed of blouse and trousers were industrially manufactured and delivered to healthcare personnel to be tested. The results are completed and supported with the perception of the healthcare staff involved in the study via a survey. Finally, the results and implications for future research are presented.
Computational NX Fluid Structure Interaction (FSI) analysis on naval three way ball valve
Authors: Dumitrache C L , Deleanu D
Published: October 2021

This article represents the continuation of a study that was presented in another paper using the NX Siemens CAD program and FSI (fluid structure interaction analysis) for a complex valve encountered in the naval domain, a ball valve known as (three way ball valve -TWB). In designing of this valve presented in the previous work, some drawings (sketches) of the component parts presented in engineering guidelines were used, all dimensions being determined by the author. In the FSI analysis the same NX Siemens program was used to discretize the solid bodies of the valve coming into contact with the fluid, materials were chosen for these bodies, boundary conditions were set and the pressure field exerted by the fluid on the solid bodies was imported. Finally a series of conclusions were drawn about the speeds, pressures of the fluid and how they are distributed on the walls of the valve, determining the so-called structural analysis “fluid structure interaction”.
Dielectric barrier discharge analysis from the point of view of supply voltage and reactor topology
Authors: Lungu C V , Hnatiuc B
Published: October 2021

This paper aims to provide a comprehensive analysis of the output of DBD reactors considering 2 different power supplies that provide rectangular command voltage with variable duty cycle and frequency. The experiments presented were performed with these power supplies considering four geometries of DBD reactor. At this stage the input parameters of the power supplies are: frequency of control pulses, duty cycle and high voltage level applied on the DBD reactors by choosing a certain number of turns for the primary windings of the high voltage coil. The parameters considered as outputs from the reactor-power supply assembly were: the high voltage output and the electric current from the primary induction coil.
Topological optimization of the mobile element structure of Gantry type CNC machine using FEA method
Authors: Petrea L , Stan G
Published: October 2021

Because of the rapid development key industries like aerospace, energy, rail transportation, engineering machinery and other industries there exist a growing demand for high speed and precise manufacturing of large and heavy parts. CNC Machine Tools with kinematical feed chains with great distance between slides, Gantry type, are the main tool to machine large and heavy parts. In such type of machines, the mobile element (the mechanical coupling between the two kinematical feed chains) has a significant effect upon the static and dynamic characteristics of the machine. Deformation of the mobile element has a significant impact upon machining accuracy. A study of the static proprieties and the deformation that effect the mobile element is extremely useful for improving the machining accuracy and efficiency of the machine. The weight of the mobile element it is extremely important and effects the overall dimension and weight of the machine. Using FEA analysis on a 3D CAD model this papers objectives are mesh optimization and topological optimization of the mobile element. This study will show that the topological optimization preformed on the mobile element has reduce the inertial forces, 10 to 30 %, while maintaining rigidity.
Modern manufacturing technology for modular photovoltaic panels: State-of-the-art and future trends
Authors: Polcovnicu RA , Țăranu N , Ungureanu D , Zghibarcea Ș , Hudișteanu VS
Published: October 2021

The technological advancement of the recent years has triggered a significant increase in the global energy consumption. Within this frame, the fossil fuels still account for most of the energy consumption as the renewable energy systems often lack reliability and predictability in terms of total energy supply. These shortcomings may be overcome if various design and manufacturing process optimization methods are applied so as to gain more benefits from the current solar power systems. A modern modular photovoltaic (PV) panel is an assembly of photovoltaic cells mounted in an adaptable framework for quick installation. The photo-voltaic cells use sunlight as source of energy and generate current electricity, which can be harvested directly or through an existing grid. A collection of PV modules can be arranged in any desirable manner to form a PV panel. Also, the implementation of such modern modular systems brings numerous advantages, including the reduction of power transmission cost and the minimization of the global warming problems. This work presents the latest findings related to the manufacturing technology and the equipment train used in the production of modern photovoltaic systems.
An alternative for wind energy conversion using improved Savonius rotor turbine model
Authors: Scheaua F D
Published: October 2021

The current society development is dependent of the planet energy resources and if we take an overview on renewable energies used worldwide it can be said that they are constantly gaining ground. This trend represents an important step forward towards maintaining a clean environment by focusing on capitalizing considerable resources that are sustainable over time, such as solar energy, together with waves and wind force. Regarding the energy production solution based on the atmospheric air masses movements or wind energy, the alternative to the constructive model of horizontal axis turbines (HAWT), currently widely used in wind farms is presented the alternative of using vertical shaft turbines (VAWT) for reduced installed power wind farms. The aspects that form the advantages of these turbines are presented as well as the fact that although they offer a lower power coefficient, they can play an important role for smaller power farms, the investment being at lower values. The basic rotor construction model is based on the SAVONIUS type which has been continuously improved, the results being better in terms of energy performance. A rotor concept that can be used within wind turbines with better performance results compared to SAVONIUS classic model is presented in this paper. The novelty elements consist in the use of a larger number of blades as well as the placing method on the rotor basic circle profile. The numerical analysis results made on virtual rotor model are presented, which highlight the improved values obtained on the analysed model.
Coupling methods and optimal use of modern anti-seismic insulation systems at building and bridge construction structures
Authors: Scheaua F D
Published: October 2021

The construction industry has recorded an unprecedented advance in recent years, especially in the world recent developed countries and this involves the increasing development of insulation techniques against the effects of seismic actions that can threaten the structure integrity at a certain time. Most recent achievements in terms of structure insulation systems are successfully used within building and bridge structures in order to ensure the optimal stability level during a potential earthquake, which allows ensuring a proper safety level both for operation and in terms of investments protection. the protection methods of the structures are directed in two directions, namely in achieving the insulation at the base of the structure by strategically positioning the systems at the base of the structure while the second direction is directed at seismic energy consumption or energy dissipation by using dissipative systems mounted on frames the resistance structure of the building. By combining the action of the two types of mechanical systems, good results can be obtained regarding the behaviour of the structure isolated by the earthquake. The paper presents constructive aspects of the mechanical systems used for the seismic insulation of both building and bridge structures and their functional role in the whole structure to which they are mounted. Through the experimental tests made are highlighted the better results in terms of acceleration for the structure isolated with the composed system. Are emphasized in this manner the protective system role in ensuring an improved behaviour for the structure where is mounted at seismic dynamic motions that can occur in time.
Influence of the positioning accuracy given by the positioning encoder of the CNC machine tools
Authors: Stan G , Stoica A
Published: October 2021

The CNC machine tools are present at a large extent worldwide, for machining by cutting all kinds of work pieces. Their machining accuracy and quality are crucial to obtaining very accurate and intricate work pieces. The accuracy of a CNC machine tool is given by the quality of each and every kinematic linkage/coupling in its structure. This work aims at researching the influence of several constructive and functional factors on the positioning accuracy of a kinematic coupling in the structure of a CNC machine tool. The influence caused by noncompliance with the Abbé principle on the positioning accuracy of a feed kinematical linkage is analysed into detail, both at idle and load running. Out of this research useful conclusions are resulting for the CNC machine tool designers and builders, with respect to optimising several constructive factors, such as the location of the position encoder, location of the ball screw, stiffness of the directional guideways etc., in order to improve the accuracy of the CNC machine tool. The results of the theoretical research have been validated through experimental trials, confirming the impossibility of full compliance with the Abbé on the CNC machine tools.
Investigations on the effect of low temperature cooling on the phase transformations of the EN AW 7075 alloy
Authors: Stoicanescu M , Crisan A , Bedo T , Varga B , Milosan I , Peter I
Published: October 2021

Al-based alloys are very challenging materials, especially in applications where energy and mass reduction are required. In this scenario, EN AW 7075 Al-based alloy can be considered of high interest for different large and thick products. One of the many fields of interest where large geometry dynamic is present is, for example, aerospace, where the alloy structural stability in different conditions is very important. In this paper, the main attention is oriented toward the structural investigation of the EN AW 7075 Al-based alloy in different condition, by differential scanning calorimeter and dilatometry analysis, in order to be able to propose it, as a suitable material for aerospace component production. The analysis on the conditioned and un-conditioned materials has been used to assess the alloy’s performance and to control the evolution of the alloy properties, in specific conditions, important aspect for the targeted application. Some data on the mechanical behaviour of the alloy integrate the study.
Comparative study on the financial implications of a fire fighting intervention on an oil reservoir
Authors: Voicu I , Juganaru E D , Panaitescu V F , Panaitescu M
Published: October 2021

In this paper, the authors determine by calculation, for a storage reservoir design for petroleum products, with a volume of 50,000 m3, the required amount of foam that will be used to extinguish a fire that broke out in it. The reservoir for which the calculation is made is in the park reservoir within S.C. Oil Terminal S.A. Constanta -South Platform. The paper presents the constructive characteristics of the reservoir, for which the calculation is made, the constructive characteristics of the special extinguishing installation, the physico-chemical characteristics of the petroleum substances (gasoline, crude oil), as well as the physico-chemical characteristics of the foaming liquid used for extinguishing the fire. The calculation is made on the basis of the Norm on the fire safety of buildings, Part II Extinguishing Installations Indicative P118/2-2013, as well as on the basis of information from the Methodology for calculating the forces and means necessary for extinguishing fires.
Research on small caliber weapons firing ranges security enhancement considering the projectile-obstacle impact
Authors: Zvîncu N-D , Moldoveanu C-E , Mandache-Dodoiu A-D , Dîrloman F-M , Vedinaș I
Published: October 2021

Weapons systems are used to gain a tactical, strategic, material or mental advantage over an adversary or enemy target. The modern weapons systems are designed to be technologically complex but practical for operator usage. The firing phenomenon consists of a multitude of mechanical and thermodynamic processes with the result being the movement of the projectile towards a chosen target. The projectile movement from the weapon to the point of impact defines its trajectory.

Firing ranges are locations where military personnel is operating certain weapons systems in order to achieve specific results and certain levels of readiness. Due to increasing urbanisation of the areas adjacent to firing ranges, monitoring the projectile trajectory becomes mandatory in order to be able to provide a secure climate for both military personnel and civilians.

It is the purpose of the author to provide the numerical simulation tool (a MATLAB application) which is useful for tracking the projectile trajectory from the muzzle of the weapon to the impacted obstacle. By computing the useful information obtained with the internal and external ballistics, the theoretical trajectory of a projectile can be calculated. In order to get the most accurate values, preliminary knowledge is needed. So by using appropriate tools and software, a projectile’s trajectory can be calculated if the correct values are provided (mass, diameter, initial angle, initial speed). The tool created has different weapons-ammunition specifications and initial conditions parameters loaded that can be combined with the existing drag laws known in ballistics (Siacci law, 1930 law or 1943 law) to describe the projectile movement in atmosphere. As obstacles are defined, similar to the ones existing in a firing range, the tool can assess where the impact occurred and is able to display necessary values (impact points coordinates, velocities, impact angles, etc) while also creating 3D and 2D visualisations on the integrated graphic area. This way, the tool can be used to create impact assessments for specific weapons systems and decisions can be made to enhance the security of the firing range and the firing safety.

Three different firing range configurations are considered for comparison when using certain small caliber weapons used by NATO countries.
Comparison between milling roughing operations in full slotting manufacturing: trochoidal, plunge and conventional milling
Authors: Gómez G , Fernández De Lucio P , Del Olmo A , Martínez De Pissón G , Jimeno A , González H , López De Lacalle L N
Published: October 2021

Manufacturing improvements in terms of manufacturing-chain costs and times reduction are becoming a real need in the industry, especially for roughing operations. To satisfy these industrial requirements, more efficient machining processes have been developed, such as High Efficiency Milling (HEM). According to the above mentioned direction, trochoidal milling appears as an efficient method for roughing operations of full slots. This work presents an analysis in terms of production time between conventional, plunge and trochoidal milling to determine which process configuration is more productive.
Milling angular references and process parameters on fiber reinforced plastics
Authors: Navarro M D , Meseguer M D , Ordeig I , Lluch J
Published: October 2021

Machining of fiber-reinforced composites produces delamination in the workpiece. In bidirectional long fiber fabric reinforced composites, delamination depends on different parameters. In this work, two parameters are studied: fiber orientation angle respect to machining direction and the distance of the warp yarn from the trimmed edge until the next dip below the crossing fill. This work defines angles relating fiber orientation with cutting and feed movements and their relations in a robust way, being applied to edge trimming and grooving operations. On the other hand, for Type II delamination, three different kinds of delamination (constant, uniform pattern variation and random) are studied taking into account fiber orientation, wick size and the fiber orientation angle respect to machining direction.
Latest trends in basalt fibre applications and implications of machining processes
Authors: Domingo R , De Agustina B , Marín M M , Calvo R
Published: October 2021

Lastly the use of basalt fibre as reinforcement in organic matrix composites has had a particular attention. Applications in products intended for industry or for final consumer have been increased. The good thermal and mechanical proprieties in environmental typical and extremes conditions have facilitated such uses. Moreover, the development of cryogenic machining can contribute, as environmentally friendly process, in these materials because are support extremes temperatures. Thus, a systematic literature review has been carried out through PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology. At first approximation, it has allowed to identify the main applications of this material, such as transport sector, in several products types (automobiles, drones, bicycles, among others). Few research groups dedicated to this field have been identified, and they are focused especially on the materials properties. Respect to machining processes, several works have been found and in all of them, the operations were executed in dry and at room temperature. Therefore, a new development is possible through the cryogenic machining in basalt fibre reinforced composites.
On machining of Calmax steel by EDM: an experimental study
Authors: Karmiris P , Papazoglou E L , Leszczyńska B , Zagórski K , Markopoulos A P
Published: October 2021

Electrical Discharge Machining (EDM) is a non-conventional machining process in which the material removal occurs by utilizing thermoelectric energy. EDM’s inherent properties render it a feasible method in machining hard-to-cut materials, like tool steels. The current study presents an experimental study regarding the machining of Calmax, a chromium - molybdenum - vanadium alloyed steel, with EDM. The control parameters are the pulse-on current, the pulse-on time and the open-circuit voltage, while the machining performance was estimated in terms of the Material Removal Rate (MRR), the Tool Wear Ratio (TWR) and the Arithmetic Average Roughness (Ra). The experiments were carried out based on Taguchi DOE and an L16 orthogonal array design. Finally, for the aforementioned performance indexes, Analysis Of Variance (ANOVA) was performed to determine how the machining parameters impact the process’ results.
Preliminary study of the hardening effect and fatigue behaviour enhancement through vibration assisted ball burnishing on C45 Steel
Authors: Velázquez E , Marqués J A , Fernández I , Travieso J A , Jerez R , Llumà J
Published: October 2021

The objective of this paper is to present a preliminary study of the effects of ball burnishing with vibration assistance on cycle fatigue endurance of cylindrical specimens subjected to bending stress and obtain the best input parameters. The specimens were burnished through 6 different combinations of preload force, number of passes and vibration assistance, finding that burnishing while applying a 90-N preload and 5 passes derives in the longest lifespan, being the vibration assistance not significant with this combination. In terms of roughness, it has been proved that the vibration assistance improves the finishing significatively, allowing to reduce the number of passes compared to NVABB and, as optimal ball-burnishing parameters, the 90-N preload and 5 passes combination derivates in a 93% improvement in terms of mean roughness of the surface. It is also been proved the hardening effect provoked by the ball-burnishing, being an improvement estimated around the 51% in the best case.
Enactive manufacturing through cyber-physical systems: a step beyond cognitive manufacturing
Authors: Martín A M , Ávila M J , Aguayo F
Published: October 2021

Cognitive manufacturing, as a paradigm for providing intelligence to manufacturing systems and enabling interaction with operators presents limitations. Manufacturing system requires to be adaptive to machine tools, manufacturing environments and operators. In this line, the enactive approach to cognitive science provides a paradigm for the design of new biologically inspired cognitive architectures. Likewise, the advantages of Key Enabling Technologies and the concept of Industry 4.0 reveal new opportunities for increasing industrial innovation and developing sustainable industrial environments. These technologies are appropriated to overcome the limitations of cognitive manufacturing, because they can achieve the integration of physical and digital systems focused on cyber-physical systems. In this work, an architecture for the sustainable development of enactive manufacturing systems based on holonic paradigm is proposed and its main associated informational model is described.
Validation of the sandblasting process in the manufacturing of precision spheres for non-contact metrology
Authors: Cuesta E , Meana V , Pastur P , Álvarez B J , Zapico P
Published: October 2021

In order to ensure the measurements that can be made with non-contact metrology technologies, it is necessary to use verification and calibration procedures using precision artefacts as reference elements. In this environment, the need for increasingly accurate but also more cost-effective calibration artefacts is a clear demand in industry. The aim of this work is to demonstrate the feasibility of using low-cost precision spheres as reference artefacts in calibration and verification procedures of non-contact metrological equipment. Specifically, low-cost precision stainless steel spheres are used as reference artefacts. Obviously, in order for such spheres to be used as standard artefacts, it is necessary to change their optical behaviour by removing their high brightness. For this purpose, the spheres are subjected to a manual sandblasting process, which is also a very low-cost process. The equipment used to validate the experiment is a laser triangulation sensor mounted on a Coordinate Measuring Machine (CMM). The CMM touch probe, which is much more accurate, will be used as a device for measuring the influence of sandblasting on the spheres. Subsequently, the influence of this post-processing is also checked with the laser triangulation sensor. Ultimately, the improvement in the quality of the point clouds captured by the laser sensor will be tested after removing the brightness, which distorts and reduces the quantity of points as well as the quality of the point clouds. In addition to the number of points obtained, the parameters used to study the effect of sandblasting on each sphere, both in contact probing and laser scanning, are the measured diameter form error, as well as the standard deviation of the point cloud regarding the best-fit sphere.
Experimental investigation of contact forces and temperatures in rubbing interactions of honeycomb interstate seals
Authors: Soler D , Saez De Buruaga M , Arrazola P J
Published: October 2021

The new architecture of high velocity aircraft engines includes labyrinth-honeycomb interstate seals to improve the engine’s stability. To increase these engines capacity a commonly used strategy is to reduce the clearance between the blades and the sealing system. However, this reduction causes non-desired contacts (rubbing) between the rotating and static components of the engine. This rubbing interaction has an adverse effect on the engine life (wear and thermal cracking) and efficiency. In this work, experimental tests were carried out to recreate the rub between an F110 steel fin and a Hastelloy X honeycomb seal. A conventional CNC machine controlled the sliding and penetration velocities, and the interaction forces and fin tip temperatures were measured during the rub. Results demonstrate the dependence that both, interaction forces and tip temperatures, have with sliding and penetration velocities. However, it is clear that this influence is more pronounced in relation to the sliding velocity.
Numerical analysis of necking in stretch-bending based on modified maximum force criteria
Authors: Morales D , Borrego M , López J A , Martínez A J , Centeno G , Vallellano C
Published: October 2021

The necking criteria based on the maximum force principle, such as the Swift and Hill necking models, have been extensively used in the past to study sheet formability. Many extensions or modifications of these criteria have been proposed to improve necking predictions under only stretching conditions. Recently, the authors proposed two approaches to predict necking under stretch-bending conditions: a generalisation of classical maximum force criteria to stretch-bending; and a necking criterion based on critical distance concepts, suggesting that necking is controlled by the damage of a critical material volume located at the inner side of the sheet. Both approaches were evaluated with analytical models and the failure was successfully predicted in different materials, such as steel, brass and aluminium. This work presents a numerical study of the proposed necking criteria in stretch-bending processes with different punch radii. The simulations are validated with experimental tests over H240LA steel sheets.
Design and construction of a test bench for the manufacture and on-machine non-contact inspection of parts obtained by Fused Filament Fabrication
Authors: Peña F , Fernández C , Valiño G , Álvarez B J , Rico J C , Mateos S
Published: October 2021

Industrial application of additive manufacturing (AM) technologies is subjected to limitations related to the lack of dimensional and geometrical accuracy of manufactured parts. Many works were dedicated to improve quality of parts manufactured by AM, but integrated solutions in commercial-type AM machines have not been achieved yet. With this aim, the present work describes the design, manufacture and starting-up of a mechatronic test bench first prototype, with the double capability of 3D printing by Fused Filament Fabrication (FFF) and non-contact inspection of deposited layers. Both systems operate coordinately as the part is constructed. Final tests describe the effectiveness of both integrated systems and state the basis for further research.
Topology optimization and additive manufacturing applied to a camera bracket for a 3U CubeSat
Authors: Serrano M , Andrés E M , González I
Published: October 2021

This work is aimed to perform the optimization of the design of a camera bracket for a 3U CubeSat. The weight of the initial design is 1.15 kg which needs to be reduced below 150 g, maintaining enough stiffness to withstand the launch loads. Topology Optimization is applied with Altair’s OptiStruct Inspire software to fulfil the mass reduction requirement, with promising result. Lastly, a PLA prototype is manufactured via Additive Manufacturing.
Preliminary study of Augmented Reality based manufacturing for further integration of Quality Control 4.0 supported by metrology
Authors: Ho P T , Albajez J A , Yagüe J A , Santolaria J
Published: October 2021

Augmented Reality (AR) is a key technology enabling Industry 4.0, which enriches human perspectives by overlaying digital information onto the real world. The maturity of AR technology has grown recently. As processes in the automotive and aeronautic sectors require high quality and near-zero error rates to ensure the safety of end-users, AR can be implemented to facilitate workers with immersive interfaces to enhance productivity, accuracy and autonomy in the quality sector. In order to analyse whether there is a real and growing interest in the use of AR as assisting technology for manufacturing sector in general and quality control in particular, two specific research questions are defined. In addition, two well-known research databases (Scopus, Web of Science) are used for the paper selection phase in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology to conduct a preliminary study and evaluate the current development of AR applications in manufacturing sector in order to answer the defined questions. It is found that while the development of AR technology has widely implemented to assign real-time information to several systems and processes in assembly and maintenance sectors, this tendency has only emerged in the quality sector over the last few years. However, AR-based quality control has proved its advantages in improving productivity, accuracy and precision of operators as well as benefits to manufacturing in terms of product and process quality control across different manufacturing phases.
Path towards embedding industry 4.0 paradigm – Digital competence overview in HEI: The Alto Minho Region case study
Authors: Pereira T , Amaral A , Barreto L
Published: October 2021

The increased adoption of IoT and analytical devices, telecommunication systems, smart sensors, and diverse information systems have brought significant impacts to Industry 4.0. To respond to this rapid technological evolvement is essential to ensure a proper articulation of HEI (Higher Education Institutions) with industry, to better prepare graduates with the appropriate competencies and technological capabilities within the digital transition of the industry. This paper aims to present a research project developed in digital transformation amongst HEI students, in the Alto-Minho region disclosing the trigger points to increase the digital adoption and embedding of Industry 4.0 paradigm. The obtained results enabled to conclude an apparent low level of digital literacy, a lack of vision and awareness about the technology potentialities throughout industry activities, besides its use almost restricted to leisure and as study support, as well as lack on cybersecurity domain-specific competencies.
Maintenance management and Optimization of the thermoforming process for the agri-food industry using the S2 model
Authors: Álvarez F J , Salgado D R , González A G , Pérez O L , Romero F
Published: October 2021

The agri-food industry has been greatly enhanced in recent years with the introduction of process control and the automation [1] of certain links in the production chain. The seasons of the year in which these machines must be operational and show robust and reliable operation, have short durations (2 to 4 months) and are therefore greatly affected by unexpected failures that cause stops on the production lines. This paper attempts to expose a comparative advantages that can be obtained in terms of availability and efficiency in the thermoforming process. With the introduction of Industry 4.0 [2, 4] and the S2 model [5] and actuator control and early action, it is possible to optimize availability and efficiency ratios on thermoformer machines. Results show that it’s possible to reduce unexpected failures by means of this optimization tools. Two improvement strategies are outlined. Maintenance Management improvement model improves response to failures but does not optimize the useful life of the components. Algorithm life optimization based on S2 model optimizes service life and improves response to failure.
Performance analysis of teaching methodologies applied to graduate subjects on risk engineering and management in industrial environments
Authors: Rodríguez A , González C , Sebastián M A
Published: October 2021

In the risk engineering and management teaching, technical guides need to be complemented with standards, regulations, guides and professional criteria of Spanish and international prestigious institutions. This situation allows the extension of teaching opportunities, addressed to design teaching activities focused on the analysis and knowledge of considered industrial safety technologies. For this, from the Manufacturing Engineering area of the National Distance Education University, a methodology based on the simulation of the actual Health & Safety professional practice has been developed. In this work, an analysis of the student’s opinions on the teaching methodology of several National Distance Education University subjects related to industrial risk engineering and management is performed. The study covers a period of five academic years, collecting a total of 232 surveys. The analysis methodology has allowed to obtain a general view related to the student satisfaction. Among, the conclusions, it can be highlighted the satisfaction with evaluation model, the flexibility, the quality of contents and the teaching methodology. Finally, in the future, this methodology will be used to perform another teaching performance based on other approaches based, for example, specifically in the training -obtained in these subjects- for professional issues.