11 research outputs found

    New mononuclear cobalt (III) and manganese (III) complexes containing a hexadentate schiff base ligand

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    Manganese and cobalt complexes in high oxidation state play an important role in a diverse range of enzymatic and electron-transfer processes in biological systems1 and as antibacterial or antiviral agents2 . Here, we report the synthesis and crystal structures of two new mononuclear complexes [MnL](ClO4) (1) and [CoL](NO3)·2CH3OH (2) containing N,N’- bis[(2-hydroxybenzilideneamino)propyl]-piperazine (H2L) (Figure 1). X-ray structure determinations of 1 and 2 revealed that both compounds consist of mononuclear complex cations containing trivalent metal centers, MnIII or CoIII. The metal ions are coordinated in a distorted octahedral fashion by the N4 donor set of the ligand in basal and the two phenoxo oxygen atoms in apical positions. Spectral properties are consistent with the crystallographic results and the electrochemical properties of the complexes have been investigated by cyclic voltammetry. Furthermore, thermal studies were performed to deduce the stabilities of the ligand and complex

    Comparative study on metal versus zirconium dioxide infrastructure manufacturing in prosthetic rehabilitation in the maxillary frontal zone

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    Prosthetic rehabilitation of the maxillary front teeth is an extremely laborious problem for the dental team, consisting of the dentist and the dental technician. If for the physiognomic component the most recommended materials are the ceramic masses, for the resistance substrate there are several variants. Conventional technologies using dental alloys and modern ones involving the use of zirconium dioxide can be used successfully in performing fixed prosthetic restorations in the maxillary frontal area, both options having both advantages and disadvantages, as we will describe in this material

    Overview and future challenges of nearly zero energy buildings (nZEB) design in Southern Europe

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    In times of great transition of the European construction sector to energy efficient and nearly zero energy buildings (nZEB), a market observation containing qualitative and quantitative indications should help to fill out some of the current gaps concerning the EU 2020 carbon targets. Next to the economic challenges, there are equally important factors that hinder renovating the existing residential building stock and adding newly constructed high performance buildings. Under these circumstances this paper summarises the findings of a cross-comparative study of the societal and technical barriers of nZEB implementation in 7 Southern European countries. The study analyses the present situation and provides an overview on future prospects for nZEB in Southern Europe. The result presents an overview of challenges and provides recommendations based on available empirical evidence to further lower those barriers in the European construction sector. The paper finds that the most Southern European countries are poorly prepared for nZEB implementation and especially to the challenge opportunity of retrofitting existing buildings. Creating a common approach to further develop nZEB targets, concepts and definitions in synergy with the climatic, societal and technical state of progress in Southern Europe is essential. The paper provides recommendations for actions to shift the identified gaps into opportunities for future development of climate adaptive high performance buildings. (C) 2017 Elsevier B.V. All rights reserved.info:eu-repo/semantics/publishedVersio

    Modeling, simulation and experimental research for MEMS cantilevers of complex geometry

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    The fundamental resonant frequencies for MEMS cantilevers of complex geometry (paddle-shaped rectangular microbeam, homogeneous on a part of length and nonhomogeneous, layered structure to the wider part of the beam) are calculated. A method of analytical calculation using the Mohr-Maxwell theory is proposed for homogeneous microcantilevers, which is then adapted for non-homogeneous structures. The analytical model has been validated by numerical simulation using finite element method (FEM). The experimental validation has been made using laser-Doppler vibrometry (LDV) by scanning with the Polytec MSA-500 system

    Economic Efficiency of High-Entropy Alloy Corrosion-Resistant Coatings Designed for Geothermal Turbine Blades: A Case Study

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    The aim of this paper is to establish the cost-effectiveness of high-entropy alloy coatings, using the electrospark deposition technique, designed for a geothermal turbine blade’s leading edge. The deposition of materials with high resistance to corrosion and erosion aims to increase the blade’s service life, reduce maintenance costs and improve production efficiency. According to our previous research on the CoCrFeNiMox high-entropy alloy system, the results showed a high corrosion resistance when in bulk or as a coating, and when tested in geothermal steam and in a saline solution. Based on the results, the high-entropy alloy was subjected to further analyses. The paper focused on two aspects of the research. The first direction was to explore the possibility of obtaining an effective, protective high-entropy alloy layer by the electrospark deposition method. To this end, various tests were performed to demonstrate that the new material possesses superior properties and is suitable for the geothermal environment’s demands. The second direction was to calculate the economic efficiency of coating the areas intensely subjected to wear, based on reports published by the geothermal power plants’ representatives. The final costs were compared with the commercially available equipment parts, and also with the general maintenance costs. From the calculation of the cost efficiency for the CoCrFeNiMo0.85 high-entropy alloy, it resulted that the deposition method and the properties of the material are suitable for the operating conditions, representing an efficient and easy to apply solution to reduce maintenance costs in the geothermal industry

    Economic Efficiency of High-Entropy Alloy Corrosion-Resistant Coatings Designed for Geothermal Turbine Blades: A Case Study

    No full text
    The aim of this paper is to establish the cost-effectiveness of high-entropy alloy coatings, using the electrospark deposition technique, designed for a geothermal turbine blade’s leading edge. The deposition of materials with high resistance to corrosion and erosion aims to increase the blade’s service life, reduce maintenance costs and improve production efficiency. According to our previous research on the CoCrFeNiMox high-entropy alloy system, the results showed a high corrosion resistance when in bulk or as a coating, and when tested in geothermal steam and in a saline solution. Based on the results, the high-entropy alloy was subjected to further analyses. The paper focused on two aspects of the research. The first direction was to explore the possibility of obtaining an effective, protective high-entropy alloy layer by the electrospark deposition method. To this end, various tests were performed to demonstrate that the new material possesses superior properties and is suitable for the geothermal environment’s demands. The second direction was to calculate the economic efficiency of coating the areas intensely subjected to wear, based on reports published by the geothermal power plants’ representatives. The final costs were compared with the commercially available equipment parts, and also with the general maintenance costs. From the calculation of the cost efficiency for the CoCrFeNiMo0.85 high-entropy alloy, it resulted that the deposition method and the properties of the material are suitable for the operating conditions, representing an efficient and easy to apply solution to reduce maintenance costs in the geothermal industry

    Role of optimal medication given to patients with hypertension and ischemic heart disease prior to an acute coronary syndrome

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    IntroductionAdministering optimal cardiovascular medication (OCM) to patients with hypertension (HBP) and ischemic heart disease (IHD) lowers cardiovascular morbidity and mortality.The main objective of this study was to compare in-hospital cardiac mortality among patients with HBP and/or IHD, treated or untreated with OCM, who developed a first episode of acute coronary syndrome (ACS).MethodsThe study was carried out retrospectively and included patients admitted with a first episode of ACS between 2013 and 2016. The patients were divided into three groups: those with HBP, IHD, and a history of HBP + IHD. Patients were then divided into two subgroups: subgroup A consisted of patients undergoing optimal anti-ischemic and/or antihypertensive therapy, while subgroup B consisted of patients without OCM.ResultsThis analysis comprised 1096 patients. Mean age was 64.3 ± 18 years. There were 581 patients in subgroup A – 53%, and 515 patients in subgroup B – 47%. Total cardiac mortality was 9.98%, different depending on the groups and subgroups studied: HBP group total – 7%, subgroup A – 5.1%, significantly lower compared to subgroup B – 9.4% (p = 0.05); IHD group total – 12.2%, subgroup A – 9.07%, significantly lower compared to subgroup B – 15.8% (p = 0.05); HBP + IHD group total – 14.35%, subgroup A – 9.9%, significantly lower compared to subgroup B – 18.8% (p = 0.05).ConclusionsThe lack of OCM in patients with HBP and/or IHD is correlated to a significant increase in in-hospital cardiac mortality among patients who develop a first-episode ACS
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