59 research outputs found
The Quality of Educational Services in Higher Education – Assurance, Management or Excellence?
The present paper has as its target to present the regulations characterizing the quality of educational services in higher education, with a view to identifying the system which is the most efficient and revealing for their real quality. This approach also takes into account the central role that key intellectual and cultural responsibilities play in the development of modern society, as well as the moral impact of higher education on society as a whole. The authors reach the conclusion that, in order to have real quality in higher education, it is important to introduce a quality management system and to constantly improve it, using as feedback the satisfaction of clients and other interested parties, with the intention of attaining performance and excellence.excellence, performance, quality management, quality assurance, quality indicators
LÃmites de subordinación del empleado al empleador y autocracia laboral
The employment relationship (relationship) is characterized by a specific way of subordinating the employee, which determines the so-called "private government", characterized by the exercise of arbitrary control over the employee and the power of domination that the employer has over the employee's life. outside working hours. Such a trend is appreciated as the manifestation of labor autocracy. The state and its specialized structures must have a much higher degree of involvement, facilitating a dialogue through which employees can actually have a say in the organization of workLa relación laboral (relación) se caracteriza por una forma especÃfica de subordinación del trabajador, que determina el llamado "gobierno privado", caracterizado por el ejercicio de un control arbitrario sobre el trabajador y el poder de dominación que tiene el empleador sobre la vida del trabajador. fuera del horario laboral. Esta tendencia se aprecia como manifestación de la autocracia laboral. El estado y sus estructuras especializadas deben tener un grado mucho mayor de participación, facilitando un diálogo a través del cual los empleados puedan realmente tener voz en la organización del trabajo
Anodic oxidation of sulphite ions on smooth nickel based layer platinum nanoparticles in alkaline solution
In this paper, nickel based 1 layer platinum nanoparticles electrode (Ni-Pt1layer), prepared by spray-pyrolysis technique, it has been tested in order to obtain a complete characterization for the process of anodic oxidation of sulphite to sulphate in alkaline media. This process was investigated by cyclic voltammetry technique and linear polarization. The present study concerns the preliminary evaluation of electrocatalytic properties for this type of electrode toward the electrochemical oxidation of sulphite
Skeletal nickel based 6 layers platinum nanoparticles electrode with catalytic effect for anodic oxidation of sulphite in alkaline solution
In this paper, anodic oxidation of sulphite ions on skeletal nickel based 6 layers platinum nanoparticles electrode (Nisk – Pt6layers) in aqueous alkaline solution was investigated by cyclic voltammetry and linear polarization. The present research is essential to understand the mechanism of reaction on this electrode. The preliminary results presented in experimental part confirm the high catalytic activity of Nisk – Pt6layers for sulphite electrooxidation process and offer the possibility to use this type of electrodes in alkaline fuel cells
Capsaicin extract ss corrosion inhibitor for carbon steel in sodium chloride aqueous solution
In this paper are presented preliminary results obtained using capsaicin extract as corrosion inhibitor for carbon steel in sodium chloride aqueous solution. Capsaicin is a chili pepper extract with analgesic properties. The electrochemical behavior of capsaicin in sodium chloride solution was examined by cyclic voltammetry Further, the inhibitory effect was studied by linear polarization and Tafel method in order to determin the kinetic parameters, providing informations about the the mechanism of inhibitory effect. The diminution of corrosion rate of carbon steel in the presence of capsaicin can be attributed to the inhibitor molecules adsorbtion on the sample surface and blocking the active sites, or depositing corrosion products on the metal surface
Passivation of Co/Al2O3 Catalyst by Atomic Layer Deposition to Reduce Deactivation in the Fischer-Tropsch Synthesis
The present work explores the technical feasibility of passivating a Co/γ-Al2O3catalyst byatomic layer deposition (ALD) to reduce deactivation rate during Fischer-Tropsch synthesis (FTS).Three samples of the reference catalyst were passivated using different numbers of ALD cycles (3, 6and 10). Characterization results revealed that a shell of the passivating agent (Al2O3) grew aroundcatalyst particles. This shell did not affect the properties of passivated samples below 10 cycles, inwhich catalyst reduction was hindered. Catalytic tests at 50% CO conversion evidenced that 3 and6 ALD cycles increased catalyst stability without significantly affecting the catalytic performance,whereas 10 cycles caused blockage of the active phase that led to a strong decrease of catalytic activity.Catalyst deactivation modelling and tests at 60% CO conversion served to conclude that 3 to 6 ALDcycles reduced Co/γ-Al2O3deactivation, so that the technical feasibility of this technique was provenin FTS
The effect of Mg location on Co-Mg-Ru/gamma-Al2O3 Fischer-Tropsch catalysts
The effectiveness of Mg as a promoter of Co-Ru/γ-Al(2)O(3) Fischer–Tropsch catalysts depends on how and when the Mg is added. When the Mg is impregnated into the support before the Co and Ru addition, some Mg is incorporated into the support in the form of Mg(x)Al(2)O(3+x) if the material is calcined at 550°C or 800°C after the impregnation, while the remainder is present as amorphous MgO/MgCO(3) phases. After subsequent Co-Ru impregnation Mg(x)Co(3−x)O(4) is formed which decomposes on reduction, leading to Co(0) particles intimately mixed with Mg, as shown by high-resolution transmission electron microscopy. The process of impregnating Co into an Mg-modified support results in dissolution of the amorphous Mg, and it is this Mg which is then incorporated into Mg(x)Co(3−x)O(4). Acid washing or higher temperature calcination after Mg impregnation can remove most of this amorphous Mg, resulting in lower values of x in Mg(x)Co(3−x)O(4). Catalytic testing of these materials reveals that Mg incorporation into the Co oxide phase is severely detrimental to the site-time yield, while Mg incorporation into the support may provide some enhancement of activity at high temperature
Effect of Pretreatment Method on the Nanostructure and Performance of Supported Co Catalysts in Fischer−Tropsch Synthesis
ABSTRACT: Understanding precursor transformation to active catalysts is crucial to heterogeneous Fischer−Tropsch (FT) catalysis directed toward production of hydrocarbons for transportation fuels. Despite considerable literature on FT catalysis, the effect of pretreatment of supported cobalt catalysts on cobalt dispersion, dynamic atomic structure, and the activity of the catalysts is not well understood. Here we present systematic studies into the formation of active catalyst phases in supported Co catalyst precursors in FT catalysis using in situ environmental (scanning) transmission electron microscopy (E(S)TEM) with single-atom resolution under controlled reaction environments for in situ visualization, imaging, and analysis of reacting atomic species in real time, EXAFS, XAS, DRIFTS analyses, and catalytic activity measurements. We have synthesized and analyzed dried reduced (D) and dried calcined reduced (DC) Co real catalysts on reducible and nonreducible supports, such as SiO2, Al2O3, TiO2, and ZrO2. Comparisons of dynamic in situ atomic structural observations of reacting single atoms, atomic clusters, and nanoparticles of Co and DRIFTS, XAS, EXAFS, and catalytic activity data of the D and DC samples reveal in most cases better dispersion in the D samples, leading to a larger number of low-coordination Co0 sites and a higher number of active sites for CO adsorption. The experimental findings on the degree of reduction of D and 27 DC catalysts on reducible and nonreducible supports and correlations between hexagonal (hcp) Co sites and the activity of the catalysts generate structural insights into the catalyst dynamics, important to the development of efficient FT catalysts
Novel cobalt zinc oxide Fischer-Tropsch catalysts synthesised using supercritical anti-solvent precipitation
Cobalt zinc oxide catalysts have been prepared by anti-solvent precipitation in supercritical CO2 and investigated for CO hydrogenation. Here we show how the textural and catalytic properties of the catalyst can be tailored by the addition of water to the initial solution of cobalt and zinc acetates in methanol. Characterization of the catalysts by powder X-ray diffraction, infra-red and Raman spectroscopy showed that in the absence of water a high surface area mixed acetate was produced which upon calcination formed wurtzite type Zn1−xCoxO and spinel type ZnxCo3−xO4. The addition of 5 vol.% water resulted in a phase separated Co3O4/ZnO catalyst and enhanced active cobalt surface area as a result of disruption of the solvent/CO2 phase equilibrium during precipitation
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