RF disturbances produced by high-power photovoltaic solar plants

In this thesis, analysis of electromagnetic compatibility of high-power photovoltaic solar plant is made. Current standards suitable for photovoltaic applications are given. Measurements of antenna factor for experimental setup are shown. Also, measurements of common mode disturbance voltages in high-power solar plant are given. Importance of DC-side filter is shown. In the last part of the work, electromagnetic simulations are made. These simulations show influence of several factors to EMC of power plant. Based on these simulations and measurements recommendations are given.

Imazapyr root exudation from eucalypt seedlings cultivated in nutritive solution

Imazapyr has been used in Brazilian eucalypt cultivation for the maintenance of clearings and coppicing control in areas undergoing stand reform. However, inquiries have been made as to the final fate of the molecule. Imazapyr root exudation in eucalypt plants was evaluated through a bioassay under greenhouse conditions, by applying different herbicide doses (0.000, 0.375, 0.750, 1.125, and 1.500 kg ha-1 a.i.) on Eucalyptus grandis seedlings derived from vegetative propagation, hydroponically cultivated in 2.500 ml vases. Forty-day-old seedlings of the same clone were used as bioindicators, transplanted to the vases two days after herbicide application. After a period of 13 days of coexistence, the sprayed plants were removed and discarded; ten days later, the visual symptoms of toxicity were evaluated and the total dry biomass (aerial part and roots) of the bioindicators were determined. The lowest herbicide dose (0.375 kg ha-1 a.i.) affected the total biomass and growth, being most evident in the aerial part, with larger I50 for root dry biomass. The E. grandis seedlings exuded imazapyr, and/or its metabolites, in concentrations capable of affecting the growth of plants of the same species.

Solution Business Model for Energy Efficiency

This study examined solution business models and how they could be applied into energy efficiency business. The target of this study was to find out, what a functional solution business model applied to energy efficiency improvement projects is like. The term “functionality” was used to refer not only to the economic viability but to environmental and legal aspects and also to the implement of Critical Success Factors (CSFs) and the ability to overcome the most important market barriers and risks. This thesis is based on a comprehensive literature study on solution business, business models and energy efficiency business. This literature review was used as a foundation to an energy efficiency solution business model scheme. The created scheme was tested in a case study which studied two different energy efficiency improvement projects, illustrated the functionality of the created business model and evaluated their potential as customer targets. Solution approach was found to be suitable for energy efficiency business. The most important characteristics of a good solution business model were identified to be the relationship between the supplier and customer, a proper network, knowledge on the customer’s process and supreme technological expertise. Thus the energy efficiency solution business was recognized to be particularly suitable for example for energy suppliers or technological equipment suppliers. Because the case study was not executed from a certain company’s point of view, the most important factors such as relationships and the availability of funding could not be evaluated. Although the energy efficiency business is recognized to be economically viable, the most important factors influencing the profitability and the success of energy efficiency solution business model were identified to be the proper risk management, the ability to overcome market barriers and the realization of CSFs.

Communicative and Anticipatory Decision-Making Supported by Bayesian Networks

The purpose of this research is to draw up a clear construction of an anticipatory communicative decision-making process and a successful implementation of a Bayesian application that can be used as an anticipatory communicative decision-making support system. This study is a decision-oriented and constructive research project, and it includes examples of simulated situations. As a basis for further methodological discussion about different approaches to management research, in this research, a decision-oriented approach is used, which is based on mathematics and logic, and it is intended to develop problem solving methods. The approach is theoretical and characteristic of normative management science research. Also, the approach of this study is constructive. An essential part of the constructive approach is to tie the problem to its solution with theoretical knowledge. Firstly, the basic definitions and behaviours of an anticipatory management and managerial communication are provided. These descriptions include discussions of the research environment and formed management processes. These issues define and explain the background to further research. Secondly, it is processed to managerial communication and anticipatory decision-making based on preparation, problem solution, and solution search, which are also related to risk management analysis. After that, a solution to the decision-making support application is formed, using four different Bayesian methods, as follows: the Bayesian network, the influence diagram, the qualitative probabilistic network, and the time critical dynamic network. The purpose of the discussion is not to discuss different theories but to explain the theories which are being implemented. Finally, an application of Bayesian networks to the research problem is presented. The usefulness of the prepared model in examining a problem and the represented results of research is shown. The theoretical contribution includes definitions and a model of anticipatory decision-making. The main theoretical contribution of this study has been to develop a process for anticipatory decision-making that includes management with communication, problem-solving, and the improvement of knowledge. The practical contribution includes a Bayesian Decision Support Model, which is based on Bayesian influenced diagrams. The main contributions of this research are two developed processes, one for anticipatory decision-making, and the other to produce a model of a Bayesian network for anticipatory decision-making. In summary, this research contributes to decision-making support by being one of the few publicly available academic descriptions of the anticipatory decision support system, by representing a Bayesian model that is grounded on firm theoretical discussion, by publishing algorithms suitable for decision-making support, and by defining the idea of anticipatory decision-making for a parallel version. Finally, according to the results of research, an analysis of anticipatory management for planned decision-making is presented, which is based on observation of environment, analysis of weak signals, and alternatives to creative problem solving and communication.

Mathematical analysis of maximum power generated by photovoltaic systems and fitting curves for standard test conditions

The rural electrification is characterized by geographical dispersion of the population, low consumption, high investment by consumers and high cost. Moreover, solar radiation constitutes an inexhaustible source of energy and in its conversion into electricity photovoltaic panels are used. In this study, equations were adjusted to field conditions presented by the manufacturer for current and power of small photovoltaic systems. The mathematical analysis was performed on the photovoltaic rural system I-100 from ISOFOTON, with power 300 Wp, located at the Experimental Farm Lageado of FCA/UNESP. For the development of such equations, the circuitry of photovoltaic cells has been studied to apply iterative numerical methods for the determination of electrical parameters and possible errors in the appropriate equations in the literature to reality. Therefore, a simulation of a photovoltaic panel was proposed through mathematical equations that were adjusted according to the data of local radiation. The results have presented equations that provide real answers to the user and may assist in the design of these systems, once calculated that the maximum power limit ensures a supply of energy generated. This real sizing helps establishing the possible applications of solar energy to the rural producer and informing the real possibilities of generating electricity from the sun.

Performance of UASB reactors in two stages followed by post-treatment with activated sludge in wastewater batch of wet-processed coffee

In this study it was evaluated the efficiency of the treatment of wet-processed coffee wastewater in upflow anaerobic sludge blanket (UASB) reactors in two stages, in bench scale, followed by post-treatment with activated sludge in batch. The first UASB reactor was submitted to an hydraulic retention time (HRT) of 6.2 d and organic loading rates (OLR) of 2.3 and 4.5g CODtotal (L d)-1, and the second UASB reactor to HRT of 3.1 d with OLR of 0.4 and 1.4g CODtotal (L d)-1. The average values of the affluent CODtotal increased from 13,891 to 27,926mg L-1 and the average efficiencies of removal of the CODtotal decreased from 95 to 91%, respectively, in the UASB reactors in two stages. The volumetric methane production increased from 0.274 to 0.323L CH4 (L reactor d)-1 with increment in the OLR. The average concentrations of total phenols in the affluent were of 48 and 163mg L-1, and the removal efficiencies in the UASB reactors in two stages of 92 and 90%, respectively, and increased to 97% with post-treatment. The average values of the removal efficiencies of total nitrogen and phosphorus were of 57 to 80% and 44 to 60%, respectively, in the UASB reactors in two stages and increased to 91 and 84% with the post-treatment.

Concentration of injetion solution and its effects on soil and on yield of fertirrigated banana cv. Terra Maranhão

The Fertigation is the combined application of water and nutrients to a crop. It can be adapted to all types of agricultural crops. The objective of this study was to evaluate the effect of urea concentration in irrigation water on electrical conductivity of the soil solution and saturation extract along the first cycle of banana cv. Terra Maranhão. The experiment followed a completely randomized design with six treatments and ten replications. Treatments regarded for using three urea concentrations (1.0; 2.5 and 4.0 g L-1) in irrigation water applied by two micro irrigation systems (microsprinkler and drip). Results showed that there was a linear elevation of electrical conductivity of saturation extract and soil solution with the increase on concentration of urea in the injection solution. Urea should be used under concentrations up to 2.5 g L-1 in irrigation water without causing increase on electric conductivity of soil solution and saturation extract, considering 1.1 dS m-1 as the tolerated value for the crop. Nitrate in the soil solution increased significantly with the increase of urea concentration in the injection solution. The maximum concentration of nitrate in the soil occurred for 4,0 g L-1 concentration of the injection solution.

Designing the transformation from a boiler supplier into a solution seller

Competition for customers in business-to-business markets is rough, and in order to survive a seller has to be able to deliver more value to its customers than its competitors. This thesis is done for the sales department of an energy technology company operating in business-to-business markets. The company is a relatively small in its field, and it aims to expand internationally and differ itself from its competitors by providing better service for its customers and selling solutions. This study aims to design the transformation from a product seller into a solution seller by defining what is a solution and how solutions are sold, and creating an action plan for sales. Data for the study is collected in ten theme interviews, and analyzed with thematic and content analysis. The action plan is constructed based both on the data and theory. According to the findings of the study, solution is defined as a specially designed unique combination of elements – such as products, services, knowledge, experience and thinking – that work with and complement each other, and bring value to a particular customer. Solution sales requires capabilities to anticipate; build relationships with customers; identify needs and define requirements; cocreate solutions by customizing and integrating elements; and provide postdeployment support. Vision for the change is to sell solution through sensing customers’ needs and responding to them, and the steps of the action plan are to (1) cascade customer-focus, (2) involve other departments in solution sales, (3) develop customer relationship management, and (4) involve the whole organization in solution business.

Business on demand and its mobile solution - study with SAP ByDesign

Business On-Demand solutions are widely used by SMEs in the world today. When I started working in SAP, SAP had just launched its first version mobile solutions for Business On-Demand solutions. SAP ByDesign mobile solution is great, but I believe we could do something even better on mobile phones. My job is focusing on mobile application development. Therefore, I have lots of thoughts about how we could make the mobile solutions better serve desktop solutions and how to distinguish the mobile solutions. Finally I decide to have a further research into this area. The purpose of this thesis is trying to find out how to improve the mobile solutions for Business On-Demand, find out its benefit and limits, and distinguish SaaS mobile solutions from desktop ones. In order to conduct this research, I had some online literature search to find out the Business On-Demand market and major players in this area. I compare the materials from public internet with the ones that are used internally in SAP. I had some interviews with SAP solution manager and SAP‟s potential customers. I finally made some pro-posals for mobile SaaS solutions which I believe will make the solutions better present and much helpful to the customers.

Qualitative Characteristics and Quantitative Measures of Solution's Reliability in Discrete Optimization: Traditional Analytical Approaches, Innovative Computational Methods and Applicability

The purpose of this thesis is twofold. The first and major part is devoted to sensitivity analysis of various discrete optimization problems while the second part addresses methods applied for calculating measures of solution stability and solving multicriteria discrete optimization problems. Despite numerous approaches to stability analysis of discrete optimization problems two major directions can be single out: quantitative and qualitative. Qualitative sensitivity analysis is conducted for multicriteria discrete optimization problems with minisum, minimax and minimin partial criteria. The main results obtained here are necessary and sufficient conditions for different stability types of optimal solutions (or a set of optimal solutions) of the considered problems. Within the framework of quantitative direction various measures of solution stability are investigated. A formula for a quantitative characteristic called stability radius is obtained for the generalized equilibrium situation invariant to changes of game parameters in the case of the H¨older metric. Quality of the problem solution can also be described in terms of robustness analysis. In this work the concepts of accuracy and robustness tolerances are presented for a strategic game with a finite number of players where initial coefficients (costs) of linear payoff functions are subject to perturbations. Investigation of stability radius also aims to devise methods for its calculation. A new metaheuristic approach is derived for calculation of stability radius of an optimal solution to the shortest path problem. The main advantage of the developed method is that it can be potentially applicable for calculating stability radii of NP-hard problems. The last chapter of the thesis focuses on deriving innovative methods based on interactive optimization approach for solving multicriteria combinatorial optimization problems. The key idea of the proposed approach is to utilize a parameterized achievement scalarizing function for solution calculation and to direct interactive procedure by changing weighting coefficients of this function. In order to illustrate the introduced ideas a decision making process is simulated for three objective median location problem. The concepts, models, and ideas collected and analyzed in this thesis create a good and relevant grounds for developing more complicated and integrated models of postoptimal analysis and solving the most computationally challenging problems related to it.

Modeling and Control of the Power Conversion Unit in a Solid Oxide Fuel Cell Environment

In this doctoral thesis, a power conversion unit for a 10 kWsolid oxide fuel cell is modeled, and a suitable control system is designed. The need for research was identified based on an observation that there was no information available about the characteristics of the solid oxide fuel cell from the perspective of power electronics and the control system, and suitable control methods had not previously been studied in the literature. In addition, because of the digital implementation of the control system, the inherent characteristics of the digital system had to be taken into account in the characteristics of the solid oxide fuel cell (SOFC). The characteristics of the solid oxide fuel cell as well the methods for the modeling and control of the DC/DC converter and the grid converter are studied by a literature survey. Based on the survey, the characteristics of the SOFC as an electrical power source are identified, and a solution to the interfacing of the SOFC in distributed generation is proposed. A mathematical model of the power conversion unit is provided, and the control design for the DC/DC converter and the grid converter is made based on the proposed interfacing solution. The limit cycling phenomenon is identified as a source of low-frequency current ripple, which is found to be insignificant when connected to a grid-tied converter. A method to mitigate a second harmonic originating from the grid interface is proposed, and practical considerations of the operation with the solid oxide fuel cell plant are presented. At the theoretical level, the thesis discusses and summarizes the methods to successfully derive a model for a DC/DC converter, a grid converter, and a power conversion unit. The results of this doctoral thesis can also be used in other applications, and the models and methods can be adopted to similar applications such as photovoltaic systems. When comparing the results with the objectives of the doctoral thesis, we may conclude that the objectives set for the work are met. In this doctoral thesis, theoretical and practical guidelines are presented for the successful control design to connect a SOFC-based distributed generation plant to the utility grid.

Induction of labor with titrated oral misoprostol solution versus oxytocin in term pregnancy: randomized controlled trial

PURPOSE: To evaluate the effectiveness and the safety of orally administered misoprostol in comparison to intravenously infused oxytocin for labor induction in term pregnant women. METHODS: Between 2008 and 2010, a total of 285 term pregnant women whom were candidate for vaginal delivery were assessed for eligibility to enter the study. Twenty five patients were excluded for different reasons; and 260 included women were randomly assigned to one of the two groups according to the method of treatment, misoprostol or oxytocin. The misoprostol group received 25 µg every 2 hours for up to 24 hours for induction. The oxytocin group received an infusion of 10 IU which was gradually increased. The time from induction to delivery and induction to the beginning of the active phase and successful inductions within 12, 18, and 24 hours were recorded. The trial is registered at irct.ir, number IRCT2012061910068N1. RESULTS: Failure of induction, leading to caesarean section was around 38.3% in the oxytocin group and significantly higher than that of the misoprostol group (20.3%) (p<0.001). Despite the more prevalent failure in the oxytocin group, the mean time intervals from induction to active phase and labor of this group were both significantly less than the misoprostol group (10.1±6.1 and 13.2±7.7 versus 12.9±5.4 and 15.6±5.1 hours respectively, both p-values were <0.05). Maternal and fetal complications were comparable between groups except gastrointestinal symptoms which were encountered more frequently in the misoprostol (10.9 versus 3.9%, p=0.03). CONCLUSIONS: Misoprostol is a safe and effective drug with low complications for the induction of labor. Failure is seen less with misoprostol and caesarean sections are less frequently indicated as compared to oxytocin.