Modeling of thermoelectric module operation in inhomogeneous transient temperature field using finite element method

This paper is the result of research and operation modeling of the new systems for cooling of cutting tools based on thermoelectric module. A copper inlay with thermoelectric module on the back side was added to a standard turning tool for metal processing. For modeling and simulating the operation of thermoelectric module, finite element method was used as a method for successful solving the problems of inhomogeneous transient temperature field on the cutting tip of lathe knives. Developed mathematical model is implemented in the software package PAK-T through which numerical results are obtained. Experimental research was done in different conditions of thermoelectric module operation. Cooling of the hot module side was done by a heat exchanger based on fluid using automatic temperature regulator. After the calculation is done, numerical results are in good agreement with experimental. It can be concluded that developed mathe-matical model can be used successfully for modeling of cooling of cutting tools

Decomposition mechanism and kinetics of zinc–isophthalate complex with 2,2’-dipyridylamine as a precursor for obtaining nanosized zinc oxide

Studies related to the synthesis of nanosized ZnO as the antibacterial agent have become an interdisciplinary area gathering chemists, physicists, biologists, and medics. The broad scope of materials based on ZnO resulted in the development of various techniques for its preparation. Considering the dependence of particle shape and size onto physical and chemical properties of ZnO, the synthesis procedure is of major importance. In this work, an unconventional methodology of synthesis is proposed for obtaining nanosized ZnO. Polymeric zinc complex containing 2,2’-dipyridylamine (dipya) and dianion of 1,3-benzenedicarboxylic acid (ipht), [Zn(dipya)(ipht)]n, was used as precursor. Besides the crystal structure of [Zn(dipya)(ipht)]n which was already published [1], the luminescent properties are presented in this work. Also, the amazing antibacterial activity of this precursor prompted us to investigate the relationship between the crystal structure and thermal properties, especially if we bear in mind the lack of similar studies in the literature. Therefore, the mechanism and kinetics of its degradation was investigated under non isothermal conditions in nitrogen and air atmospheres. Degradation enthalpies, thermodynamic activation parameters, pre-exponential factor, A, and the apparent activation energy, Ea, were determined for each step using Kissinger’s and Ozawa’s equations. The complexity of degradation steps has been analyzed using isoconversional methods. TG/DCS data were collected at four different heating rates: 10, 15, 20 and 25 ºC min –1 , while the formation of nanosized ZnO was confirmed using XRPD and FESEM techniques. The influence of precursor on the crystallite size and morphology of the resulting ZnO along with its antibacterial activity was examined. The obtained results will be discussed and compared. [1] L. Radovanović, J. Rogan, D. Poleti, M. Milutinović, M.V. Rodić, Polyhedron 112 (2016) 18

Supporting an Innovation Agenda for the Western Balkans - Tools and Methodologies

The Western Balkan region has significantly improved in terms of innovation performance in the last ten years. However, in catching up with other European regions, the focus of innovation efforts should be enhanced. Exports are still far more focused on medium- and low-technology products. Innovative efforts mostly accommodate traditionally strong sectors, which do not necessarily reflect the ideal competitiveness paths for economies in the region. Although some Western Balkan economies record increases in patent activity, patent intensity in the region is still low, while, on the other hand, scientific publication production displays a stable growth trend. While Western Balkan economies are at different stages in the formation of research and innovation (R&I) policy governance systems, national research and innovation policy frameworks are continuously being improved. The enhancement of governance in the area of R&I came as the result of increased capacity building activities in the region, as well as of the real needs emerging as a result of social and economic transformation. On the other hand, R&I systems in the Western Balkan economies need to continue shifting their focus towards businesses to provide better balance between public and private sector orientation. The Joint Research Centre of the European Commission is committed to supporting the shift in innovation policies and improvement of R&I efforts and governance in the Western Balkan economies through a number of tools and activities, allowing policy instruments to be matched with the specific needs of the economy. This approach seeks efficient governance mechanisms for R&I policy by reaching out to the business sector and other important actors of the innovation ecosystem. It determines sustainable development directions for economies and ensures the continuity of policy monitoring and evaluation cycles. This ambitious challenge is translated into four specific lines of activity: (i) the application of the smart specialisation methodology to design and implement innovation strategies; (ii) capacity-building activities for technology transfer, in particular through specialised workshops, tools and instruments specifically designed to assist the academic institutions in the regional economies; (iii) support to transnational collaboration and linkages in the context of EU macro-regional strategies; and (iv) data quality enhancement. The analysis of the development potential of the Western Balkan region in terms of economic, innovative and scientific capabilities in this report is supported with the good practices addressing specific challenges in the region.JRC.B.3-Territorial Developmen

European Society of Cardiology: Cardiovascular Disease Statistics 2019

Aims The 2019 report from the European Society of Cardiology (ESC) Atlas provides a contemporary analysis of cardiovascular disease (CVD) statistics across 56 member countries, with particular emphasis on international inequalities in disease burden and healthcare delivery together with estimates of progress towards meeting 2025 World Health Organization (WHO) non-communicable disease targets. Methods and results In this report, contemporary CVD statistics are presented for member countries of the ESC. The statistics are drawn from the ESC Atlas which is a repository of CVD data from a variety of sources including the WHO, the Institute for Health Metrics and Evaluation, and the World Bank. The Atlas also includes novel ESC sponsored data on human and capital infrastructure and cardiovascular healthcare delivery obtained by annual survey of the national societies of ESC member countries. Across ESC member countries, the prevalence of obesity (body mass index ≥30 kg/m2) and diabetes has increased two- to three-fold during the last 30 years making the WHO 2025 target to halt rises in these risk factors unlikely to be achieved. More encouraging have been variable declines in hypertension, smoking, and alcohol consumption but on current trends only the reduction in smoking from 28% to 21% during the last 20 years appears sufficient for the WHO target to be achieved. The median age-standardized prevalence of major risk factors was higher in middle-income compared with high-income ESC member countries for hypertension {23.8% [interquartile range (IQR) 22.5–23.1%] vs. 15.7% (IQR 14.5–21.1%)}, diabetes [7.7% (IQR 7.1–10.1%) vs. 5.6% (IQR 4.8–7.0%)], and among males smoking [43.8% (IQR 37.4–48.0%) vs. 26.0% (IQR 20.9–31.7%)] although among females smoking was less common in middle-income countries [8.7% (IQR 3.0–10.8) vs. 16.7% (IQR 13.9–19.7%)]. There were associated inequalities in disease burden with disability-adjusted life years per 100 000 people due to CVD over three times as high in middle-income [7160 (IQR 5655–8115)] compared with high-income [2235 (IQR 1896–3602)] countries. Cardiovascular disease mortality was also higher in middle-income countries where it accounted for a greater proportion of potential years of life lost compared with high-income countries in both females (43% vs. 28%) and males (39% vs. 28%). Despite the inequalities in disease burden across ESC member countries, survey data from the National Cardiac Societies of the ESC showed that middle-income member countries remain severely under-resourced compared with high-income countries in terms of cardiological person-power and technological infrastructure. Under-resourcing in middle-income countries is associated with a severe procedural deficit compared with high-income countries in terms of coronary intervention, device implantation and cardiac surgical procedures. Conclusion A seemingly inexorable rise in the prevalence of obesity and diabetes currently provides the greatest challenge to achieving further reductions in CVD burden across ESC member countries. Additional challenges are provided by inequalities in disease burden that now require intensification of policy initiatives in order to reduce population risk and prioritize cardiovascular healthcare delivery, particularly in the middle-income countries of the ESC where need is greatest

Multi-objective optimization of single pass turning using performance diagrams

Maximization of productivity and minimization of cost with acceptable quality of the parts are the most important goals of the production. In machining multi-objective optimization is a real problem. For solving this problem modern optimization methods are used. In this paper is presented a multi-objective optimization of single-pass turning of stainless steel with coated carbide tool using performance diagrams

LASER CUTTING MACHINES FOR 3-D THIN SHEET PARTS

Laser cutting machines are used for precise contour cutting thin sheet. In industrial application nowadays various types and construction of laser cutting machines can be met. For contour cutting 3-D thin sheet parts laser cutting machines with rotation movements and laser robots are used. Laser generates the light beam, that presents a tool in working process. Application of laser cutting machines made possible good quality of products, flexibility of production and enlargement of econom

Determination of Manufacturing Process Conditions by Using MCDM Methods: Application in Laser Cutting

Manufacturing is a primary generator of wealth of the country and is essential for economic growth. Determination of the most suitable manufacturing process conditions for a given application is very complex task and requires consideration of a number of conflicting and diverse process performance characteristics (criteria). In this paper the application of a recent multi-criteria decision making (MCDM) method, i.e. weighted aggregated sum product assessment (WASPAS) for determination of manufacturing process conditions in laser cutting was discussed. Laser cutting experiment was conducted based on Taguchi's L9 experimental design by varying the laser power, cutting speed, assist gas pressure and focus position at three levels. Based on obtained experimental results, a MCDM model consisting of nine alternatives and six criteria was defined. In order to determine the relative significance of considered criteria a pair-wise comparison matrix of the AHP method was used. Stability of the obtained ranking of alternatives was checked by varying values of coefficient of linear combination and by the application of operational competitiveness ratings analysis (OCRA) method

Synthesis, Structure, Morphology and Properties of Biphasic ZnO–ZnMn2O4

Transition metal oxides are important materials that have found many applications, as capacitors, sensors or in energy storage [1]. Synthesis of these compounds has been realized by various methods, such as hydro(solvo)thermal synthesis, precipitation, microwave synthesis or sol-gel synthesis [2]. Recently, the thermolysis of coordination compounds as precursors has been considered as a new approach in obtaining functional nanosized materials. [3]. In this way, by selecting the proper precursor, it is possible to control the phase composition, morphology and particle size of a resulting material [3]. The biphasic powder composed of ZnO (zincite) and ZnMn2O4 (hetaerolite), (I) has been obtained by thermolysis of bimetallic complex [MnZn2(dipya)3(tpht)3(H2O)4]·2H2O (dipya = 2,2’-dipyridylamine, tpht = dianion of 1,4-benzenedicarboxylic acid) at 450 °C during 1 h in air atmosphere. Scanning Electron Microscopy (SEM) was used to investigate the morphology of I (Figure 1). It can be observed that the morphology consists of deformed spherical grains of ZnO with an average diameter of 67 nm and elliptical grains of hetaerolite whose average diameter and length were 156 and 290 nm, respectively. The X-ray powder diffraction (XRPD) was applied to investigate the structure of I. In Figure 2 two-phase Rietveld refinement Electron Microscopy of Nanostructures ELMINA 2018, August 27-29, 2018 172 pattern of I is presented (ZnO to ZnMn2O4 phase-ratio of 62:38 wt. %). The main crystallographic data and Rietveld refinement parameters for ZnO phase are: hexagonal, space group P63mc, a = 3.2574(1), c = 5.2175(2) Å, V = 47.945(3) Å3 ; for ZnMn2O4 phase are: tetragonal, space group I41/amd, a = 5.7299(3), c = 9.3000(8) Å, V = 305.34(3) Å3 ; Rwp = 4.80 %, Rp = 3.82 %, Rexp = 3.80 % and χ2 = 1.5960. UV- Vis-NIR absorption spectrum was measured in order to investigate the direct band gap (Eg) of I. Due to the existence of two phases in I, two different Eg values of 2.4 and 3.3 eV for ZnMn2O4 and ZnO phase, respectively, were determined using Kubelka-Munk function. The mean size, polydispersity index (PDI) and zeta potential of spherical grains were measured using Zetasizer Nano Series, Nano ZS. The mean size was 418.6±53.1 nm while PDI value was found to be 0.354±0.099. Relatively high values of PDI and low apostate value of zeta potential (–6.55 mV) are indications of incipient instability of colloidal dispersion of I, probably due to the formation of agglomerates [4, 5]. Photoluminescence measurements were carried out at room temperature on Fluorolog-3 Model FL3-221 spectrofluorimeter system upon excitation at 350 nm, in order to study the optical properties of I. This analysis revealed one band centred at 422 nm in the blue region of the visible part of the spectrum, which can possibly be associated with defects in the crystal structure of the ZnO phase [6]. References: [1] C Yuan et al, Angewandte Chemie International Edition 53 (2014), 1488. [2] CNR Rao and B Raveau in “Transition Metal Oxides: Structure, Properties, and Synthesis of Ceramic Oxides” 2nd edition (WILEY-VCH, New York). [3] MY Masoomi and A Morsali, Coordination Chemistry Reviews 256 (2012), 2921. [4] R Greenwood and K Kendall, Journal of the European Ceramic Society 19 (1999), 479. [5] M Staiger et al, Journal of Dispersion Science and Technology 23 (2002), 619. [6] H Zeng et al, Advanced Functional Materials 20 (2010), 561. [7] The authors acknowledge funding from the Ministry of Education, Science and Technological Development of the Republic of Serbia, Grant Number III45007