Papers by Nicolae Ungureanu
Advanced Engineering Letters
Information systems in small manufacturing companies can have a big impact on increasing economy ... more Information systems in small manufacturing companies can have a big impact on increasing economy and productivity. Due to limited human and financial resources, these companies generally use cheaper commercial solutions or develop specialized information system solutions that are adapted to their needs. In order to properly solve the problem of introducing an information system, a thorough analysis of information flows in the company and corresponding business processes is necessary. The main subject and goal of the research in this work is related to the investigation of time losses due to the absence of an information system from the aspect of managing the flow of cutting tools, as well as the presentation of the foundations for its development in a small manufacturing company.
Zenodo (CERN European Organization for Nuclear Research), Sep 17, 2020
Purposeincreasing the survival rate of SMEs. Methodology/approachan analysis of the socioeconomic... more Purposeincreasing the survival rate of SMEs. Methodology/approachan analysis of the socioeconomic framework for the NorthWest development region of Romania using a mixed research, both qualitatively and quantitatively through the survey methodquestionnaire and the analysis and the interpretation of information from the National Office of the Trade Register. Findingsthere are signs that the total number of SMEs in the NorthWest development region of Romania will decrease. In addition, half of the SMEs that participated in the survey do not use management tools to meet the company's objectives. Research limitations/implicationsthe risk matrix do not eliminate risk, but rather prioritizes the appropriate use of resources and time and facilitate the decision-making. Practical implications-SMEs do not have an entire arsenal of strategic weapons and are often led by the owner-manager who runs the risk of failure following their own ideologies and practices. Originality/valuethe use of a risk matrixan innovative management tool for SMEs with which the management (entrepreneur) will identify and quantify the risks to which the company is exposed, will increase the survival chance of SMEs.
In this paper are present/exists two methods of gravel rim’s tensions and deformations under the ... more In this paper are present/exists two methods of gravel rim’s tensions and deformations under the pressure effect created of shoe-brake in the brake process. The first method so called the classic one has at the bottom of it known theory’s from the discipline frame the material resistance and the second method has at the bottom of it the gravel with the finite elements help. Both methods presented are applied at the brakes with miner hoisting machines.V tomto článku jsou prezentovány 2 metody analýzy napětí a deformací brzdového věnce pod zatížením vytvořeným nožní brzdou při brzdění. První metoda, nazývaná klasická, má za základ ve známé teorii z odporu materiálu a základem druhé je metoda konečných prvků. Obě metody jsou aplikované na brzdách u hornických těžebních strojů
The main component of the conveyor is the rubber mat, which, driven through specific methods, ens... more The main component of the conveyor is the rubber mat, which, driven through specific methods, ensures the transport of the excavated mass. The use of this type of transportation at optimal parameters depends on the correct stretching (tensioning) of the rubber mat. This is achieved with the help of a stretching gear with carriage (jointed to the stretching drum) with engine - driven cable.Hlavní složkou dopravníku je gumová podložka, řízená specifickou metodou, zajišťující dopravu vytěžené hmoty. Používání tohoto druhu dopravy při optimálních parametrech závisí na správném napětí gumové podložky. Toho je možné dosáhnout pomocí napínacího zařízení (připevněno na napínacím bubnu) s motorem - řízený kabelem
The finite element method is a numerical method used for solving the complex issues of engineerin... more The finite element method is a numerical method used for solving the complex issues of engineering. The method comprises of discretion the continuous environment through assemble of finite elements, which interact between them in a finite number of nodes. The interacting forces of the nodes of the model characterize the actions of the interior forces or stresses that are applied upon the contours of the neighbouring elements.Metoda konečných prvků je numerická metoda používaná pro řešení komplexních problémů ve strojírenství. Tato metoda se skládá z průběžného prostředí shromážděných konečných prvků, které se vzájemně mezi sebou mění v konečný počet uzlů. V interakci sil uzlů v modelu charakterizují činnosti vnitřních sil a zdůrazňují, že jsou uplatňovány na kontury sousedních prvků
Advances in Manufacturing Engineering and Materials II, 2021
Realization of Lifelong Learning Programme (LLP) Project Inter-countries Research for Manufacturi... more Realization of Lifelong Learning Programme (LLP) Project Inter-countries Research for Manufacturing Advancement-IRMA represents realization of a research and comparative analysis in the 27 European Union's States, aimed at promotion of excellence, efficiency and fairness of the instruction in Higher Education Institutes. The IRMA project focuses on the Manufacturing Engineering filed, taken into consideration its high level of innovation and fast changes in requirements that students must possess, in order to be adapt and competitive on the labour market. The objectives of the IRMA project is to innovate and to improve educational systems of technical universities at European level, in order to offer to students a competitive environment based on innovative teaching methods, instruments and contents, that allows their intellectual increase and be able to satisfy new necessities and requests, emerged from the market labour.
Advances in Manufacturing Engineering and Materials II, 2021
Friction and wear behavior of new generation Ultra-High Molecular Weight Polyethylene (UHMWPE), H... more Friction and wear behavior of new generation Ultra-High Molecular Weight Polyethylene (UHMWPE), Highly Cross-Linked UHMPE (HXLPE) and Vitaminized E XLPE (VE-XLPE), sliding against TiAl6V4 alloy under dry and lubricated conditions were investigated. Tribological tests were conducted by using a reciprocating pin-on-flat tribometer under hip replacement implants conditions. Lubricated sliding tests were carried out with a biological fluid that approximates well the synovial fluid present in the joints with imposed boundary mechanism. The worn samples of the HXLPE and VE-XLPE were analyzed with a gravimetric weighing scale with a sensitivity of 0,1 mg. The evolution of the friction coefficient of the HXLPE/Ti6Al4V and VEXLPE/Ti6Al4V pairs were also compared.
This paper presents a part of the study referring to exploring Energy Recovery from Municipal Sol... more This paper presents a part of the study referring to exploring Energy Recovery from Municipal Solid Waste in Maramures County. In order to analyze the possibility of energetic recovery of municipal solid waste (MSW), data referring to the management system of MSW from Maramures county were cumulated and processed in a first stage in order to estimate the quantity of municipal solid waste and its composition, which might be recovered energetically. In the next stage, samples of municipal solid waste were collected from landfills, which were submitted to specific processing and analyses. The experimental data were processed and in the end the energy potential of municipal solid waste from Maramures county was found. This study will help stakeholders and those involved in waste management to assess the possibility of energy recovery. The analysis of the study concluded that municipal solid waste in Maramures County is a potential source of renewable energy.
Advances in Manufacturing Engineering and Materials II, 2021
This paper presents part of a research on the tribological approach of the process of drilling of... more This paper presents part of a research on the tribological approach of the process of drilling of massive rock mechanics. The general concepts of tribo-systems are presented, then we proceed to customize them. So the following are presented: the tribo-system structure, drilling parameters, the mining tribo-system itself, its implementation in a material plan, and attempts to particularize for roto-percussive perforation.
IOP Conference Series: Materials Science and Engineering, 2020
A thorough determination of the loading of the ankle joint is useful both for the optimal design ... more A thorough determination of the loading of the ankle joint is useful both for the optimal design of prostheses and for the preclinical testing in terms of tribological performances. In vivo measurements of joint forces are usually not easy in the in-vivo settings, then non-invasive in-silico methods should be considered. Nowadays resultant joint loads can be reliably estimated by using musculoskeletal modelling in an inverse dynamic approach, starting by motion data obtained in gait analysis laboratories for several human activities. The main goal of this study was to provide a set of dynamical loading curves obtained by the AnyBody Modelling SystemTM (AMS) computer software starting from ground reaction forces and kinematic data obtained by Vaughan et al. in the case of human normal gait. The model accounts for 70 Hill modelled muscles and the muscular recruitment strategy was choose as polynomial criteria. The results are presented in terms of Antero Posterior, Proximo Distal, Med...
Materials Science Forum, 2018
This paper presents the results of a microscopic investigation of fractured Storz type fire hose ... more This paper presents the results of a microscopic investigation of fractured Storz type fire hose couplings. It is part of the authors’ previous investigations on the failure mechanisms of this type of couplings. The investigations were performed using optical and scanning electron microscopy with Field Emission Gun (FED) and X-ray Energy Dispersive Spectrometer (EDS). It is shown that the AlSi5Cu1Mg casting alloy, used for the fabrication of these couplings, presents a normal microstructure. Thus, the nucleation and growth of micro-cracks in the investigated couplings are not related to the alloy’s microstructural defects and must be generated by a different process.
MATEC Web of Conferences, 2018
The improvement of the gear cutting process by hob milling is also significant for the producers ... more The improvement of the gear cutting process by hob milling is also significant for the producers of gears as well as for the producers of hob milling tools. Due to the complexity of the process, the high values of the gears, and in particular the hob milling tool, the research of the bases for optimizing the process of gear cutting by hob milling requires significant financial resources and significant efforts of the researchers. In the modern production of gears there is a continuous demand for increasing the economy. In the gear cutting process improvements of the production equipment and materials for the cutting elements of the hob milling tools are necessary. In this paper an analysis of the tool life of coated hob milling tools for gear cutting of cylindrical gears is given. The experimental results have shown that the hob milling tools with inserted combs coated with TiAlN outperform the hob milling tools with inserted combs coated with TiN. They have higher resistance of 60....
International Journal of Industrial Engineering and Management, 2018
All state-of-the-art Tool condition Monitoring systems (TCM), especially those that use vibration... more All state-of-the-art Tool condition Monitoring systems (TCM), especially those that use vibration sensors, in the tool wear recognition task, heavily depend on the choice of descriptors that contain information concerning the tool wear state, which are extracted from the particular sensor signals. All other postprocessing techniques do not manage to increase the recognition precision if those descriptors are not discriminative enough. In this work, we propose toll wear monitoring strategy, which relies on the novel texture based descriptors. We consider the module of the Short Term Discrete Furrier Transform (STDFT) spectra obtained from the particular vibration sensors signal utterance, as the 2D textured image. This is done by identifying the time scale of STDFT as the first dimension, and the frequency scale as the second dimension of the particular textured image. The obtained textured image is then divided into particular 2D texture patches, covering part of the frequency range of interest. After applying the appropriate filter bank, for each predefined frequency band 2D textons are extracted. From those, for each band of interest, by averaging in time, we extract information regarding the Probability Density Function (PDF) of those textons in the form of lower order moments, thus obtaining the robust tool wear state descriptors. We validate the proposed features by the experiments conducted on the real TCM system, obtaining the high recognition accuracy.
Tehnicki vjesnik - Technical Gazette, 2017
Preliminary communication The paper represents a part from the researches referring to the tribol... more Preliminary communication The paper represents a part from the researches referring to the tribological aspects of the brakes of the mining hoisting machines. The study consists in experimental determination of the wear intensity for the friction material in contact with rim brakes. Relying on usual theoretical considerations and experimental models, first was measured the wear intensity of the friction material in accordance with the initial speed of the brake rim, the surface roughness of the rim, and the contact pressure between the brake shoe and the rim. Secondly, the least-squares method was applied for the statistical weight determination of the parameters on the wear intensity.
IOP Conference Series: Materials Science and Engineering, 2017
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Papers by Nicolae Ungureanu