Investment recovery period in electric motor of higher efficiency in pumping for irrigation

In this study, it was adjusted a mathematical model to measure the effect of electric motor efficiency on pumping system costs for irrigation on the tariff structure of conventional electricity and green horo-seasonal , and also to calculate the recovery period of the invested capital in higher efficiency equipment. Then, it was applied to a center pivot irrigation system in two options of electric motor efficiency, 92,6% (standard line) and 94,3% (high efficiency line), and the acquisition cost of the first corresponded to 70% the of the second. The power of the electric motor was 100hp. The results showed that the model allowed us to evaluate if a high efficiency motor was economically viable compared to the standard motor in each tariff structure. The high efficiency motor was not viable in the two tariff structures. In the green horo-seasonal tariff, would only be viable if its efficiency was 4.46% higher than the standard motor. In the conventional tariff, it would only be viable if the efficiency overcame 2.71%.

Investment recovery period in electric motor of higher efficiency in pumping for irrigation

Neste trabalho, ajustou-se um modelo matemático para quantificar o efeito do rendimento do motor elétrico sobre os custos de um sistema de bombeamento para irrigação na estrutura tarifária de energia elétrica convencional e horo-sazonal verde, bem como calcular o tempo de recuperação do capital investido no equipamento de maior rendimento. em seguida, o mesmo foi aplicado a um sistema de irrigação tipo pivô central em duas opções de rendimento do motor elétrico: 92,6% (linha padrão) e 94,3% (linha alto rendimento), sendo que o custo de aquisição do primeiro correspondeu a 70% do segundo. A potência do motor elétrico era de 100 cv. Os resultados mostraram que o modelo permitiu avaliar se um motor de alto rendimento era viável economicamente em relação ao motor-padrão em cada estrutura tarifária. Nas duas estruturas tarifárias, o motor de alto rendimento não foi viável. Na tarifa horo-sazonal verde, somente seria viável se seu rendimento fosse 4,46% superior ao do motor-padrão. Na tarifa convencional, somente seria viável se o ganho de rendimento superasse 2,71%.

Hospital Efficiency: Directed internship: Deloitte & NOVA SBE

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

Increasing the efficiency of utilization of soil and fertilizer phosphorus in the subtropical and tropical agricultural systems C

As a rule, soils of the subtropical and tropical regions, in which rainfall is not limiting, are acidic, and low in phosphorus, and, to a less extent, in other macro and micronutrients as well, such a sulfur, boron and zinc. The establishment of a permanent agricultural prac. tice therefore, demands relatively high usage of liming and phosphatic fertilization, to begin with. Several approaches, not mutually exclusive, could be used in order to increase the efficiency of utilization of soil and fertilizer phosphorus so that, goal of diminishing costs of production is reached. The use of liming materials bringing up pH to 6.0-6.5 causes the conversion of iron and aluminum phosphates to more available calcium phosphates; on the other hand, by raising calcium saturation in the exchange complex, it improves the development and operation if the root system which allows c or a higher utilization of all soil nutrients, including phosphorus, and helps of stand water deficits which may occur. The role of mycorrhizal fungi should be considered as a way of increasing soil and fertilizer P utilization, as well as the limitations thereof. Screening of and breeding for varieties with higher efficiency of uptake and utilization of soil and fertilizer phosphorus leads to a reduction in cost of inputs and to higher benefit/cost ratios. Corrective fertilization using ground rock phosphate helps to saturate the fixation power of the soil thereby reducing, as a consequence, the need for phosphorus in the maintenance fertilization. Maintenance fertilization, in which soluble phos-phatic sources are used, could be improved by several means whose performance has been proved: limimg, granula tion, placement, use of magnesium salts. Last, cost of phosphate fertilization could be further reduced, without impairing yields, through impairing yields, through changes in technology designed to obtain products better adapted to local conditions and to the availability or raw materials and energy sources.

Motor Types Comparison Determining Efficiency in Pumping Systems

Pumping, fan and compressor systems consume most of the motor electricity power in both the industrial and services sectors. A variable speed drive brings relevant improvements in a fluid system leading to energy saving that further on can be translated into Mtons reduction of CO 2 emissions. Standards and regulations are being adopted for fluid handling systems to limit the less efficiency pumps out of the European market on the coming years and a greater potential in energy savings is dictated by the Energy Efficiency Index (EEI) requirements for the whole pumping system and integrated pumps. Electric motors also have an International Efficiency (IE) classification in order to introduce higher efficiency motors into the market. In this thesis, the applicability of mid-size common electric motor types to industrial pumping system took place comparing the motor efficiency characteristics with each other and by analyzing the effect of motor dimensioning on the pumping system and its impact in the energy consumption.

Efficiency of extrinsic and intrinsic charge-carrier photogeneration processes obtained from the steady-state photocurrent action spectra of poly(p-phenylene vinylene) derivatives

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mechanism and Efficiency of Cell Death of Type II Photosensitizers: Effect of Zinc Chelation

A series of meso-substituted tetra-cationic porphyrins, which have methyl and octyl substituents, was studied in order to understand the effect of zinc chelation and photosensitizer subcellular localization in the mechanism of cell death. Zinc chelation does not change the photophysical properties of the photosensitizers (all molecules studied are type II photosensitizers) but affects considerably the interaction of the porphyrins with membranes, reducing mitochondrial accumulation. The total amount of intracellular reactive species induced by treating cells with photosensitizer and light is similar for zinc-chelated and free-base porphyrins that have the same alkyl substituent. Zinc-chelated porphyrins, which are poorly accumulated in mitochondria, show higher efficiency of cell death with features of apoptosis (higher MTT response compared with trypan blue staining, specific acridine orange/ethidium bromide staining, loss of mitochondrial transmembrane potential, stronger cytochrome c release and larger sub-G1 cell population), whereas nonchelated porphyrins, which are considerably more concentrated in mitochondria, triggered mainly necrotic cell death. We hypothesized that zinc-chelation protects the photoinduced properties of the porphyrins in the mitochondrial environment.

Efficiency of extrinsic and intrinsic charge-carrier photogeneration processes obtained from the steady-state photocurrent action spectra of poly(p-phenylene vinylene) derivatives

The efficiency of the charge-carrier photogeneration processes in poly(2,5-bis(3',7'-dimethyl-octyloxy)-1,4-phenylene vinylene) (OC(1)OC10-PPV) has been analyzed by the spectral response of the photocurrent of devices in ITO/polymer/Al structures. The symbatic response of the photocurrent action spectra of the OC1OC10-PPV devices, obtained for light-excitation through the ITO electrode and for forward bias, has been fitted using a phenomenological model which considers that the predominant transport mechanism under external applied electric field is the drift of photogenerated charge-carriers, neglecting charge-carrier diffusion. The proposed model takes into account that charge-carrier photogeneration occurs via intermediate stages of bounded pairs (excitonic states), followed by dissociation processes. Such processes result in two different contributions to the photoconductivity: The first one, associated to direct creation of unbound polaron pairs due to intrinsic photoionization; and the second one is associated to secondary processes like extrinsic photoinjection at the metallic electrodes. The results obtained from the model have shown that the intrinsic component of the photoconductivity at higher excitation energies has a considerably higher efficiency than the extrinsic one, suggesting a dependence on the photon energy for the efficiency of the photogeneration process.

High efficiency envelope tracking buck converter for RFPA using GaN HEMTs

—In this paper, application of a new technological solution for power switches based on Gallium Nitride and a filter design methodology for high efficiency Envelope Amplifier in RF transmitters are proposed. Comparing to Si MOSFETs, GaN HEMTs can provide higher efficiency of the Envelope Amplifier, due to better Figure Of Merit (lower product of on- resistance and gate charge). Benefits of their application were verified through the experimental results. The goal of the filter design is to generate the envelope reference with the minimum possible distortion and to improve the efficiency of the Amplifier, obtaining the optimum trade-off between conduction and switching losses.

Envelope amplifier based on switching capacitors for high efficiency RF amplifiers

Modern transmitters usually have to amplify and transmit signals with simultaneous envelope and phase modulation. Due to this property of the transmitted signal, linear power amplifiers (class A, B, or AB) are usually used as a solution for the power amplifier stage. These amplifiers have high linearity, but suffer from low efficiency when the transmitted signal has high peak-to-average power ratio. The Kahn envelope elimination and restoration technique is used to enhance the efficiency of RF transmitters, by combining highly efficient, nonlinear RF amplifier (class E) with a highly efficient envelope amplifier in order to obtain a linear and highly efficient RF amplifier. This paper presents a solution for the envelope amplifier based on a multilevel converter in series with a linear regulator. The multilevel converter is implemented by employing voltage dividers based on switching capacitors. The implemented envelope amplifier can reproduce any signal with a maximum spectral component of 2 MHz and give instantaneous maximum power of 50 W. The efficiency measurements show that when the signals with low average value are transmitted, the implemented prototypes have up to 20% higher efficiency than linear regulators used as a conventional solution.

Public sector efficiency, foreign aid and small island development states

This paper examines the efficiency of public sector expenditures and foreign aid at achieving social sector outcomes in Small Island Developing States (SIDS). Efficiency is estimated using a Stochastic Production Function (SPF) approach and panel data since 1990. A second stage of the analysis examines the determinants of efficiency. Results indicate that the efficiency of aid and public sectors at improving life expectancy has deteriorated during the 1990s but efficiency at improving school enrolments has increased. Higher levels of governance are associated with higher efficiency. There is also evidence to suggest that efficiency is lower in SIDS, as well as in Sub-Saharan Africa.

Determination of a Total Body Model of Efficiency Applied to a Rowing Movement in Humans

Efficiency represents the ratio of work done to energy expended. In human movement, it is desirable to maximise the work done or minimise the energy expenditure. Whilst research has examined the efficiency of human movement for the lower and upper body, there is a paucity of research which considers the efficiency of a total body movement. Rowing is a movement which encompasses all parts of the body to generate locomotion and is a useful modality to measure total body efficiency. It was the aim of this research to develop a total body model of efficiency and explore how skill level of participants and assumptions of the modelling process affected the efficiency estimates Three studies were used to develop and evaluate the efficiency model. Firstly, the efficiency of ten healthy males was established using rowing, cycling and arm cranking. The model included internal work from motion capture and efficiency estimates were comparable to published literature, indicating the suitability of the model to estimate efficiency. Secondly, the model was developed to include a multi-segmented trunk and twelve novice and twelve skilled participants were assessed for efficiency. Whilst the efficiency estimates were similar to published results, novice participants were assessed as more efficient. Issues such as the unique physiology of trained rowers and a lack of energy transfers in the model were considered contributing factors. Finally the model was redeveloped to account for energy transfers, where skilled participants had higher efficiency at large workloads. This work presents a novel model for estimating efficiency during a rowing motion. The specific inclusion of energy transfers expands previous knowledge of internal work and efficiency, demonstrating a need to include energy transfers in the assessment of efficiency of a total body action.

Glulam beams reinforced with FRP externally-bonded: theoretical and experimental evaluation

The glued- laminated lumber (glulam) technique is an efficient process for the rational use of wood. Fiber-reinforced polymer (FRPs) associated with glulam beams provide significant improvements in strength and stiffness and alter the failure mode of these structural elements. In this context, this paper presents guidance for glulam beam production, an experimental analysis of glulam beams made of Pinus caribea var. hondurensis species without and with externally-bonded FRP and theoretical models to evaluate reinforced glulam beams (bending strength and stiffness). Concerning the bending strength of the beams, this paper aims only to analyze the limit state of ultimate strength in compression and tension. A specific disposal was used in order to avoid lateral buckling, once the tested beams have a higher ratio height-to-width. The results indicate the need of production control so as to guarantee a higher efficiency of the glulam beams. The FRP introduced in the tensile section of glulam beams resulted in improvements on their bending strength and stiffness due to the reinforcement thickness increase. During the beams testing, two failure stages were observed. The first was a tensile failure on the sheet positioned under the reinforcement layer, while the second occurred as a result of a preliminary compression yielding on the upper side of the lumber, followed by both a shear failure on the fiber-lumber interface and a tensile failure in wood. The model shows a good correlation between the experimental and estimated results.

Influência da actividade do tronco inferior na sequência de activação muscular proximal durante o passo (fase de apoio) - em crianças com quadro motor diplegia

A marcha assegura uma progressão do corpo, compatível com o equilíbrio dinâmico e adaptada a potenciais factores destabilizadores, de um ponto de vista antecipatório, através de sinergias coordenadas entre os MSs, o tronco e os MIs. O tronco inferior tem um papel preponderante na marcha, sobretudo na estabilização necessária durante a fase de apoio. Esta actividade implica mobilidade pélvica e alongamento activo dos abdominais para conseguir a relação comprimento-tensão muscular óptima entre quadricípite e isquiotibiais, permitindo uma correcta sequência, timing e amplitude de activação. Nas crianças com alterações neuromotoras existem alterações no controlo do movimento e na estrutura do próprio movimento, alterando todo este processo. Como tal, este estudo tem como principal objectivo determinar a influência da actividade do tronco inferior na activação muscular proximal durante a fase de apoio da marcha, em crianças com quadro motor de diplegia, caracterizada por uma dificuldade na relação entre os membros e entre estes e o tronco. Para responder a este objectivo realizou-se um estudo de série de casos, com 2 crianças com quadro motor de diplegia. Efectuou-se EMG dos músculos abdominais, quadricípite e isquiotibiais e análise de imagem (para amplitude da CF) durante a marcha, em ambos os membros e em dois momentos de avaliação, separados por 2 meses, nos quais se realizou um protocolo de intervenção terapêutica adequado a cada caso. Os resultados indicam que a variação de amplitude da CF desde a fase de ataque ao solo à fase média de apoio é aproximadamente igual em M0e M1; concretamente, a amplitude inicial é inferior à de referência (pouca flexão) (melhor em M0) e a amplitude final é superior à de referência (pouca extensão) (melhor em M1). Estes resultados são idênticos em ambos os casos. Na EMG verificou-se uma actividade mais global e sincronizada de todos os músculos, mantendo-se aproximadamente a mesma percentagem de activação em M1, sobretudo no caso 1. No caso 2 verificou-se uma maior eficiência na variação da percentagem de activação dos abdominais, em M1, e dos isquiotibiais, à direita. Em conclusão, pode dizer-se que, em crianças com alterações neuromotoras (quadro motor de diplegia), uma actividade mais eficiente e sincronizada no tempo do tronco inferior, nomeadamente dos abdominais, contribui para uma maior capacidade de extensão da CF, durante a fase de apoio.