SUCCESSION PLANNING AND ORGANIZATIONAL SURVIVAL: EMPIRICAL STUDY ON NIGERIAN PRIVATE TERTIARY INSTITUTIONS

Organizational survival has been argued to be a primary goal or objective every organization should have. This paper proposes a conceptual framework of succession planning consisting of six variables (talent retention, turnover rate, career development, supervisor’ support, organizational conflicts and nepotism) and to explain the relationship among these variables regarding survival of organizations. The sample consists of three private tertiary institutions in Ogun-State, Southwest Nigeria. The results indicate that Talent retention, organizational conflict and nepotism positive and significantly correlated with organizational survival. On the other hand variables such as Turnover Rate, Career Development and Supervisor’ Supervision) are insignificantly correlated with organizational survival. The results are supposed to inform the leadership (management) team with essential insight into the relationship among the study variables (independent and dependent)

Convertisseurs modulaires multiniveaux pour le transport d'énergie électrique en courant continu haute tension

Les travaux présentés dans ce mémoire ont été réalisés dans le cadre d’une collaboration entre le LAboratoire PLAsma et Conversion d’Énergie (LAPLACE), Université de Toulouse, et la Seconde Université de Naples (SUN). Ce travail a reçu le soutien de la société Rongxin Power Electronics (Chine) et traite de l’utilisation des convertisseurs multi-niveaux pour le transport d’énergie électrique en courant continu Haute Tension (HVDC). Depuis plus d’un siècle, la génération, la transmission, la distribution et l’utilisation de l’énergie électrique sont principalement basées sur des systèmes alternatifs. Les systèmes HVDC ont été envisagés pour des raisons techniques et économiques dès les années 60. Aujourd’hui il est unanimement reconnu que ces systèmes de transport d’électricité sont plus appropriés pour les lignes aériennes au-delà de 800 km de long. Cette distance limite de rentabilité diminue à 50 km pour les liaisons enterrées ou sous-marines. Les liaisons HVDC constituent un élément clé du développement de l’énergie électrique verte pour le XXIème siècle. En raison des limitations en courant des semi-conducteurs et des câbles électriques, les applications à forte puissance nécessitent l’utilisation de convertisseurs haute tension (jusqu’à 500 kV). Grâce au développement de composants semi-conducteurs haute tension et aux architectures multicellulaires, il est désormais possible de réaliser des convertisseurs AC/DC d’une puissance allant jusqu’au GW. Les convertisseurs multi-niveaux permettent de travailler en haute tension tout en délivrant une tension quasi-sinusoïdale. Les topologies multi-niveaux classiques de type NPC ou « Flying Capacitor » ont été introduites dans les années 1990 et sont aujourd’hui couramment utilisées dans les applications de moyenne puissance comme les systèmes de traction. Dans le domaine des convertisseurs AC/DC haute tension, la topologie MMC (Modular Multilevel Converter), proposée par le professeur R. Marquardt (Université de Munich, Allemagne) il y a dix ans, semble particulièrement intéressante pour les liaisons HVDC. Sur le principe d’une architecture de type MMC, le travail de cette thèse propose différentes topologies de blocs élémentaires permettant de rendre le convertisseur AC/DC haute tension plus flexible du point de vue des réversibilités en courant et en tension. Ce document est organisé de la manière suivante. Les systèmes HVDC actuellement utilisés sont tout d’abord présentés. Les configurations conventionnelles des convertisseurs de type onduleur de tension (VSCs) ou de type onduleur de courant (CSCs) sont introduites et les topologies pour les systèmes VSC sont ensuite plus particulièrement analysées. Le principe de fonctionnement de la topologie MMC est ensuite présenté et le dimensionnement des éléments réactifs est développé en considérant une commande en boucle ouverte puis une commande en boucle fermée. Plusieurs topologies de cellules élémentaires sont proposées afin d’offrir différentes possibilités de réversibilité du courant ou de la tension du côté continu. Afin de comparer ces structures, une approche analytique de l’estimation des pertes est développée. Elle permet de réaliser un calcul rapide et direct du rendement du système. Une étude de cas est réalisée en considérant la connexion HVDC d’une plateforme éolienne off-shore. La puissance nominale du système étudié est de 100 MW avec une tension de bus continu égale à 160 kV. Les différentes topologies MMC sont évaluées en utilisant des IGBT ou des IGCT en boitier pressé. Les simulations réalisées valident l’approche analytique faite précédemment et permettent également d’analyser les modes de défaillance. L’étude est menée dans le cas d’une commande MLI classique avec entrelacement des porteuses. Enfin, un prototype triphasé de 10kW est mis en place afin de valider les résultats obtenus par simulation. Le système expérimental comporte 18 cellules de commutations et utilise une plate-forme DSP-FPGA pour l’implantation des algorithmes de commande. ABSTRACT : This work was performed in the frame of collaboration between the Laboratory on Plasma and Energy Conversion (LAPLACE), University of Toulouse, and the Second University of Naples (SUN). This work was supported by Rongxin Power Electronic Company (China) and concerns the use of multilevel converters in High Voltage Direct Current (HVDC) transmission. For more than one hundred years, the generation, the transmission, distribution and uses of electrical energy were principally based on AC systems. HVDC systems were considered some 50 years ago for technical and economic reasons. Nowadays, it is well known that HVDC is more convenient than AC for overhead transmission lines from 800 - 1000 km long. This break-even distance decreases up to 50 km for underground or submarine cables. Over the twenty-first century, HVDC transmissions will be a key point in green electric energy development. Due to the limitation in current capability of semiconductors and electrical cables, high power applications require high voltage converters. Thanks to the development of high voltage semiconductor devices, it is now possible to achieve high power converters for AC/DC conversion in the GW power range. For several years, multilevel voltage source converters allow working at high voltage level and draw a quasi-sinusoidal voltage waveform. Classical multilevel topologies such as NPC and Flying Capacitor VSIs were introduced twenty years ago and are nowadays widely used in Medium Power applications such as traction drives. In the scope of High Voltage AC/DC converters, the Modular Multilevel Converter (MMC), proposed ten years ago by Professor R. Marquardt from the University of Munich (Germany), appeared particularly interesting for HVDC transmissions. On the base of the MMC principle, this thesis considers different topologies of elementary cells which make the High Voltage AC/DC converter more flexible and easy suitable respect to different voltage and current levels. The document is organized as follow. Firstly, HVDC power systems are introduced. Conventional configurations of Current Source Converters (CSCs) and Voltage Source Converters (VSCs) are shown. The most attractive topologies for VSC-HVDC systems are analyzed. The operating principle of the MMC is presented and the sizing of reactive devices is developed by considering an open loop and a closed loop control. Different topologies of elementary cells offer various properties in current or voltage reversibility on the DC side. To compare the different topologies, an analytical approach on the power losses evaluation is achieved which made the calculation very fast and direct. A HVDC link to connect an off-shore wind farm platform is considered as a case study. The nominal power level is 100 MW with a DC voltage of 160 kV. The MMC is rated considering press-packed IGBT and IGCT devices. Simulations validate the calculations and also allow analyzing fault conditions. The study is carried out by considering a classical PWM control with an interleaving of the cells. In order to validate calculation and the simulation results, a 10kW three-phase prototype was built. It includes 18 commutation cells and its control system is based on a DSP-FGPA platform

Diseño, muestreo y análisis en la investigación cualitativa

Disponible en: www.unlz.edu.ar/sociales/hologramaticaEl presente artículo aborda la cuestión de los fundamentos de la aplicación de los diseños cualitativos en investigación, recorriendo las instancias de complejidad de lo social y sus implicancias. Cuando el investigador se enfrenta a la realidad social no está frente a una típica situación sujeto (que investiga) - objeto (entidad a ser medida), habitual en las ciencias de la naturaleza. Aunque el substrato biológico incide en los comportamientos de los individuos, la realidad vivenciada por cada uno es el resultado de un complejo proceso de interacción social que se denomina proceso de socialización. El investigador social, sujeto situado en un determinado orden social, intenta comprender a otros sujetos que se encuentran también sujetados como él. Como ellos, el analista social también utiliza sus significaciones para encontrarle sentido a lo que considera como real. Lo que se establece en los estudios cualitativos es una relación sujeto –sujeto; un sujeto interpretante de las interpretaciones de otros, que debe tener presente, en la medida de lo posible, las determinaciones de sus propias interpretacione

Oxygen flux through unmodified and modified La0.6Sr0.4Co0.2Fe0.8O3-8 hollow fibre membranes and application to methane oxidation

PhD ThesisImproved catalytic routes could help to transform the exploitation of the large worldwide natural gas reserves, whose principal component is methane. They transform methane into more valuable chemicals and fuels through carbon dioxide reforming of methane (CDRM), steam reforming of methane (SRM) and partial oxidation of methane (POM). These reactions facilitate the formation of syngas, which is subsequently converted to fuels through the Fischer-Tröpsch synthesis. Mixed Ionic and Electronic Conducting (MIEC) membrane reactors are of interest because they have the potential to produce high purity oxygen from air at lower costs and provide a continuous oxygen supply to reactions or/and industrial processes, and hence avoid sourcing the pure oxygen from air by conventional cryogenic separation technology. In addition, the MIEC ceramic membrane shows the ability to carry out simultaneous oxygen permeation and hydrocarbons oxidation into single compact ceramic membrane reactor at high temperature. This can reduce the capital investment for gas-to-liquid (GTL) plants and for distributing hydrogen. This study compares the oxygen release and oxygen uptake obtained through a LaSrCoFeO hollow fibre membrane (referred as LSCF6428-HFM) under an 0.60.40.20.83-δ Air/He gradient at 850°C and 900°C. The separation and quantification of these two processes permitted the determination of the oxygen incorporated into LSCF6428 structure and the development of a model for apparent overall rate constant using the molar flow of the oxygen at the inlet and outlet in different side of membrane (i.e. shell side and lumen side). The results show that the oxygen flux is enhanced by rising helium flow rates, this is due to an increased driving force for oxygen migration across the membrane and also the air flow determines the oxygen amount that permeates across the membrane. In addition, the oxygen flux improves at higher temperatures, due to its dependence on bulk oxygen diffusion and the oxygen surface reaction rates. The temperature increase improves the mobility of the lattice oxygen vacancies and also the concentration of lattice oxygen vacancies in the perovskite. The impact of surface modification was also studied by coating CoO and 5%Ni-LSCF6428 34 catalysts on the shell side surface of the LSCF6428 hollow fibre membrane for oxygen permeation. It was found that the oxygen flux significantly improved under Air/He gradient for catalyst-coated LSCF6428-HFM. However, under continuous operation conditions over a long time both the unmodified and the modified perovskite LSCF6428-HFM reactors suffered segregation of metal oxides or redistribution of metal composition at the surface membrane, although the bulk LSCF6428 membrane stoichiometry did not change. The apparent overall rate constants for oxygen permeation of the CoO/LSCF6428-HFM and 34 5%Ni/LSCF6428-HFM were enhanced 3-4 fold compared to unmodified LSCF6428-HFM. Comparison of both modified HFM reactors revealed that the apparent overall rate constants for CoO/LSCF6428-HFM were 2 fold higher than those obtained for 5%Ni- 34 LSCF6428/HFM. According to the distribution of total oxygen permeation residence for unmodified and modified LSCF6428-HFM reactor, the oxygen permeation rate is limited by surface exchange on the oxygen lean side or lumen side (R) at 850°C and 900°C and the ex contribution of bulk diffusion on the oxygen permeation rate increased with a rise in the temperature (900°C). The methane oxidation reaction was studied in unmodified and modified 5%Ni- LSCF6428/LSCF6428 hollow fibre membrane in reactors at 850°C. The results suggest that catalytic pathways in methane oxidation depended upon flow operation modes, oxygen concentration, Htreatment and on the type of catalyst. The performances in methane conversion of LSCF6428-HFM and 5%Ni/LSCF6428-HFM modules facilitated the formation of SrCO3 because of the reaction of CO2 with segregated strontium oxide.University of Newcastle upon Tyne (EPSRC

Serbia - public sector accounting review : report on the enhancement of public sector financial reporting

The government’s public financial management (PFM) Reform Program 2016-2020 foresees the gradual transition of public sector financial reporting from a cash basis to an accrual basis of accounting and the application of International Public Sector Accounting Standards (IPSAS). This will significantly improve the quality of financial information and should enable better informed decision-making, more efficient use of public funds and resources and improved fiscal performance. This Report on the Enhancement of Public Sector Financial Reporting is one output of the Serbia Public Sector Accounting Reform Technical Assistance project funded by the Swiss State Secretariat for Economic Affairs (SECO) through the Strengthening Accountability and Fiduciary Environment (SAFE) Trust Fund under the Public Sector Accounting and Reporting Program (PULSAR) which provides support for the development and implementation of public sector accounting standards. This report supports the development of a plan towards that goal by assessing the institutional framework for public sector accounting as well as the gap between Serbian public sector generally accepted accounting principles (PS GAAP) and IPSAS

Country Snapshot Serbia

A brief summary of the history and current status of religion in Serbia

Comparative Analysis Based on New Competitiveness Index

The current economic crisis points out to an even greater need to improve competitiveness. Since 2005, numerous developing countries have succeeded in increasing their competitiveness scores and decreasing the difference relative to advanced countries. The countries of Central and South Eastern Europe, to which Serbia belongs, have recorded an increase in their score by 0.3 on average, whereby the region of South Eastern Europe has achieved poorer results. During the period 2005-2011, Serbia recorded an increase in its score by 0.5, from 3.38 to 3.88. In 2011, Serbia was ranked 95th among 142 countries, with the score of 3.88. This is a decline relative to 2008 and 2005, when Serbia was ranked 85th with the scores of 3.38 and 3.90 respectively. However, this increase was not sufficient to improve Serbia’s ranking, which shows that other countries were more successful. This faces Serbia with the task to strengthen its efforts towards improving competitiveness.Competitiveness, Porter’s diamond, Productivity, Serbia