Condicionamento de um subsolo exposto no cerrado por meio de resíduos e da revegetação

Pós-graduação em Agronomia - FEIS

Freio eletrodinamométrico usando um inversor de frequência e um motor de indução trifásico

Considering that the Brazilian energy source is based on hydroelectric power plants, every moment that it does not rain enough, we are likely to suffer power outage. Making the rational use of energy not only is wise, but also important for financial issues. The industrial sector is of great importance to Brazilian economic context, because it is one that creates more wealth and jobs. It should be noted that it is one of the sectors that consume more electricity. One of the most used equipment in industry is the three phase induction motor, which ends up providing significant waste of energy. For that reasons, studying three phase induction motors is important. One of the ways to evaluate the parameter of the three phase induction motor is using a dynamometer mechanic or electric. This work aims at further studies (and development) of electrodynamometer brake, a type of electrical dynamometer, that is the only one with reversible use. This means, it is possible to measure both the torque and the power transmitted by the electric motors, by the direct method and the indirect. Besides it allows greater stability in the imposition of charges, due to its nature of being able to regenerate the energy imparted by the engines being tested

Estudo de viabilidade técnica e econômica da utilização de geração diesel no horário de ponta

Given the current energy crisis experienced in our country with the lack of rain in some areas, the energy distributors were forced to resort to thermal power plants to complement their energy production; raising the cost of electricity generation, they have been forced to repass this value to the customers through the Tariff Flags. Concerned about a substantial increase in their electric bill, some consumers were forced to look for alternatives so that their results are not affected. The use of diesel generation at peak hours is a relatively simple and inexpensive alternative that has been widely used for several industrial, commercial and service customers. In this present work, we conducted a feasibility study of the use of diesel generators at peak hours in a medium-sized hospital, calculating the depreciation period for the investment through savings in electricity bills

SELLING BIRD CONTROL

The remarks that I have prepared deal with direct contacts selling pest and bird control programs. I am going to limit my remarks to what I feel are the more important aspects of selling Bird Control. I think it is safe to say that one of the most difficult aspects of selling for most sales personnel is prospecting, that is, finding accounts to call on. Our sales personnel have to more or less come up with their own leads. They have to find out who to contact once they get there. I have found that the best prospect most of us have for selling Bird Control accounts are our present pest control accounts. Generally speaking, we try to main¬tain contact with our applicators in the field, who are in these accounts every day, asking them if there are any of their accounts that are having bird control problems. Another method of finding potential accounts, is driving around looking. It is more difficult to drive around and look for rat and/or roach problems, but generally speaking if a building or some type of business has a bird problem, it is fairly easy to locate. Another thing we can do is call on specific accounts. There are generally cer¬tain accounts that just by the manufacturing process do attract birds, for example: food plants, mills, beet plants, grain elevators, food processors, and so on. Other type operations which lend themselves to bird problems are industrial plants because of the super-structure (physical plant) that they have. Sub-stations and power plants are very attractive to birds. Some other situations that should be checked for bird problems are lumber yards and contractors' storage buildings. After deciding on a contact we get into what I call my basic four. There are four basic things that I try to impress upon our personnel to keep in mind when they go in to make a contact. The first one is the interview or actually making the contact so that you get an opportunity to have the interview, either calling for an appointment or making a "cold" call. The second one is closing for the survey. The third one is making the survey and preparing a proposal. The fourth and last one is the proposal presentation and closing of the sale. An additional item which would make a basic five is after you make the sale don't forget to follow up on the sale.

Freio eletrodinamométrico usando um inversor de frequência e um motor de indução trifásico

Considering that the Brazilian energy source is based on hydroelectric power plants, every moment that it does not rain enough, we are likely to suffer power outage. Making the rational use of energy not only is wise, but also important for financial issues. The industrial sector is of great importance to Brazilian economic context, because it is one that creates more wealth and jobs. It should be noted that it is one of the sectors that consume more electricity. One of the most used equipment in industry is the three phase induction motor, which ends up providing significant waste of energy. For that reasons, studying three phase induction motors is important. One of the ways to evaluate the parameter of the three phase induction motor is using a dynamometer mechanic or electric. This work aims at further studies (and development) of electrodynamometer brake, a type of electrical dynamometer, that is the only one with reversible use. This means, it is possible to measure both the torque and the power transmitted by the electric motors, by the direct method and the indirect. Besides it allows greater stability in the imposition of charges, due to its nature of being able to regenerate the energy imparted by the engines being tested

Estudo de viabilidade técnica e econômica da utilização de geração diesel no horário de ponta

Given the current energy crisis experienced in our country with the lack of rain in some areas, the energy distributors were forced to resort to thermal power plants to complement their energy production; raising the cost of electricity generation, they have been forced to repass this value to the customers through the Tariff Flags. Concerned about a substantial increase in their electric bill, some consumers were forced to look for alternatives so that their results are not affected. The use of diesel generation at peak hours is a relatively simple and inexpensive alternative that has been widely used for several industrial, commercial and service customers. In this present work, we conducted a feasibility study of the use of diesel generators at peak hours in a medium-sized hospital, calculating the depreciation period for the investment through savings in electricity bills

The Brazilian Experience With the Use of the Shield Wire Line Technology (SWL) for Energy Distribution

This paper presents an analysis of the impact of the lightning overvoltages on the operational performance of the energized shield wire line technology (SWL) implemented in two locations of the State of Rondonia, Brazil. The analysis covers the periods of 1996 to 2000 (SWL Jaru) and 1997 to 2002 (SWL Itapua do Oeste), and shows that lightning is responsible for most of the system outages. The paper describes the satisfactory results achieved with the system, showing that the isolation and energization of the shield wires does not deteriorate the lightning performance of the 230 kV transmission lines. Comparisons between the performances of the SWL technology, conventional 34.5 kV lines, and thermal power plants in operation in the same region are also presented. The results demonstrate the technical and economical viability of the SWL technology and show that its application can lead to a postponement of investments.

ANNEALING BEHAVIOR OF RAFM ODS-EUROFER STEEL

Oxide-dispersion-strengthened (ODS) ferritic-martensitic steels are candidates for applications in fusion power plants where micro structural long-term stability at temperatures of 650 degrees C to 700 degrees C are required. The microstructural stability of 80% cold-rolled reduced-activation ferritic-martensitic 9% Cr ODS-Eurofer steel was investigated within a wide range of temperatures (300 degrees C to 1350 degrees C). Fine oxide dispersion is very effective to prevent recrystallization in the ferritic phase field. The low recrystallized volume fraction (<0.1) found in samples annealed at 800 degrees C is associated with the nuclei found at prior grain boundaries and around coarse M23C6 particles. The combination of retarding effects such as Zener drag and concurrent recovery decrease the local stored energy and impede further growth of the recrystallization nuclei. Above 90 degrees C, martensitic transformation takes place with consequent coarsening. Significant changes in crystallographic texture are also reported.

New measurement of the B-11(p,alpha(0))Be-8 bare-nucleus S(E) factor via the Trojan horse method

A new measurement of the B-11(p,alpha(0))Be-8 has been performed applying the Trojan horse method (THM) to the H-2(B-11,alpha Be-8(0))n quasi-free reaction induced at a laboratory energy of 27 MeV. The astrophysical S(E) factor has been extracted from similar to 600 keV down to zero energy by means of an improved data analysis technique and it has been compared with direct data available in the literature. The range investigated here overlaps with the energy region of the light element LiBeB stellar burning and with that of future aneutronic fusion power plants using the B-11+p fuel cycle. The new investigation described here confirms the preliminary results obtained in the recent TH works. The origin of the discrepancy between the direct estimate of the B-11(p,alpha(0))Be-8 S(E)-factor at zero energy and that from a previous THM investigation is quantitatively corroborated. The results obtained here support, within the experimental uncertainties, the low-energy S(E)-factor extrapolation and the value of the electron screening potential deduced from direct measurements.

Fly ash as zeolites for reducing nitrogen losses by volatilization

The structural and chemical characteristics of fly ash from coal-fired mineral and fly ash zeolitized are similar to those of zeolites. Urea was added with these materials in the proportions of urea: fly ashes of 100:10, 100:20, 100:50, 100:100, with a control containing just urea. These treatments were applied in soil surface and the experimental design was a randomized block with clay and sandy soil. Nitrogen losses by ammonia volatilization and the chemical characteristics of soil fertility were evaluated. In sandy soil there was reduction of ammonia volatilization for the proportions of 100:10 and 100:20, while fly ash zeolitized and fly ash had no difference.

An adaptive solar radiation numerical model

[EN]A numerical model for the evaluation of solar radiation in different locations is presented. The solar radiation model is implemented taking into account the terrain surface using two-dimensional adaptive meshes of triangles that are constructed using a refinement/derefinement procedure in accordance with the variations of terrain surface and albedo. The selected methodology defines the terrain characteristics with a minimum number of points so that the computational cost is reduced for a given accuracy. The model can be used in atmospheric sciences as well as in other fields such as electrical engineering, since it allows the user to find the optimal location for maximum power generation in photovoltaic or solar thermal power plants...

Riconversione degli impianti saccariferi per la valorizzazione della filiera agro-energetica: analisi di impatto sul comprensorio agricolo

Il presente lavoro trae origine dagli obiettivi e dalle relative misure applicative della riforma dell’OCM zucchero del 2006 e nello specifico dal Piano nazionale per la razionalizzazione e riconversione della produzione bieticolo-saccarifera approvato dal MIPAF nel 2007. Lo studio riguarda la riconversione dello zuccherificio di Finale Emilia (MO), di appartenenza del Gruppo bieticolo-saccarifero Co.Pro.B, in un impianto di generazione di energia elettrica e termica che utilizza biomassa di origine agricola per la combustione diretta. L'alimentazione avviene principalmente dalla coltivazione dedicata del sorgo da fibra (Sorghum bicolor), integrata con risorse agro-forestali. Lo studio mostra la necessità di coltivazione di 4.400 ettari di sorgo da fibra con una produzione annua di circa 97.000 t di prodotto al 75% di sostanza secca necessari per l’alimentazione della centrale a biomassa. L’obiettivo é quello di valutare l’impatto della nuova coltura energetica sul comprensorio agricolo e sulla economia dell’impresa agricola. La metodologia adottata si basa sulla simulazione di modelli aziendali di programmazione lineare che prevedono l’inserimento del sorgo da fibra come coltura energetica nel piano ottimo delle aziende considerate. I modelli predisposti sono stati calibrati su aziende RICA al fine di riprodurre riparti medi reali su tre tipologie dimensionali rappresentative: azienda piccola entro i 20 ha, media da 20 a 50 ha e grande oltre i 50 ha. La superficie di entrata a livello aziendale, se rapportata alla rappresentatività delle aziende dell’area di studio, risulta insufficiente per soddisfare la richiesta di approvvigionamento dell’impianto a biomassa. Infatti con tale incremento la superficie di coltivazione nel comprensorio si attesta sui 2.500 ettari circa contro i 4.400 necessari alla centrale. Lo studio mostra pertanto che occorre un incentivo superiore, di circa 80-90 €/ha, per soddisfare la richiesta della superficie colturale a livello di territorio. A questi livelli, la disponibilità della coltura energetica sul comprensorio risulta circa 9.500 ettari.

Oxygen-containing polycyclic aromatic hydrocarbons (OPAHs) and their parent-PAHs in soil

In spite of the higher toxicity of oxygen-containing polycyclic aromatic hydrocarbons (OPAHs) than of their parent-PAHs, there are only a few studies of the concentrations, composition pattern, sources and fate of OPAHs in soil, the presumably major environmental sink of OPAHs. This is related to the fact that there are only few available methods to measure OPAHs together with PAHs in soil. rnThe objectives of my thesis were to (i) develop a GC/MS-based method to measure OPAHs and their parent-PAHs in soils of different properties and pollution levels, (ii) apply the method to soils from Uzbekistan and Slovakia and (iii) investigate into the fate of OPAHs, particularly their vertical transport in soilrnI optimized and fully evaluated an analytical method based on pressurized liquid extraction, silica gel column chromatographic fractionation of extracted compounds into alkyl-/parent-PAH and OPAH fractions, silylation of hydroxyl-/carboxyl-OPAHs with N,O-bis(trimethylsilyl)trifluoracetamide and GC/MS quantification of the target compounds. The method was targeted at 34 alkyl-/parent-PAHs, 7 carbonyl-OPAHs and 19 hydroxyl-/carboxyl-OPAHs. I applied the method to 11 soils from each of the Angren industrial region (which hosts a coal mine, power plant, rubber factory and gold refinery) in Uzbekistan and in the city of Bratislava, the densely populated capital of Slovakia.rnRecoveries of five carbonyl-OPAHs in spike experiments ranged between 78-97% (relative standard deviation, RSD, 5-12%), while 1,2-acenaphthenequinone and 1,4-naphtho-quinone had recoveries between 34-44%% (RSD, 19-28%). Five spiked hydroxyl-/carboxyl-OPAHs showed recoveries between 36-70% (RSD, 13-46%), while others showed recoveries &amp;amp;lt;10% or were completely lost. With the optimized method, I determined, on average, 103% of the alkyl-/parent-PAH concentrations in a certified reference material.rnThe ∑OPAHs concentrations in surface soil ranged 62-2692 ng g-1 and those of ∑alkyl-/parent-PAHs was 842-244870 ng g-1. The carbonyl-OPAHs had higher concentrations than the hydroxyl-/carboxyl-OPAHs. The most abundant carbonyl-OPAHs were consistently 9-fluorenone (9-FLO), 9,10-anthraquinone (9,10-ANQ), 1-indanone (1-INDA) and benzo[a]anthracene-7,12-dione (7,12-B(A)A) and the most abundant hydroxyl-/carboxyl-OPAH was 2-hydroxybenzaldehyde. The concentrations of carbonyl-OPAHs were frequently higher than those of their parent-PAHs (e.g., 9-FLO/fluorene &amp;amp;gt;100 near a rubber factory in Angren). The concentrations of OPAHs like those of their alkyl-/parent-PAHs were higher at locations closer to point sources and the OPAH and PAH concentrations were correlated suggesting that both compound classes originated from the same sources. Only for 1-INDA and 2-biphenylcarboxaldehyde sources other than combustion seemed to dominate. Like those of the alkyl-/parent-PAHs, OPAH concentrations were higher in topsoils than subsoils. Evidence of higher mobility of OPAHs than their parent-PAHs was provided by greater subsoil:topsoil concentration ratios of carbonyl-OPAHs (0.41-0.82) than their parent-PAHs (0.41-0.63) in Uzbekistan. This was further backed by the consistently higher contribution of more soluble 9-FLO and 1-INDA to the ∑carbonyl-OPAHs in subsoil than topsoil at the expense of 9,10-ANQ, 7,12-B(A)A and higher OPAH/parent-PAH concentration ratios in subsoil than topsoil in Bratislava.rnWith this thesis, I contribute a suitable method to determine a large number of OPAHs and PAHs in soil. My results demonstrate that carbonyl-OPAHs are more abundant than hydroxyl-/carboxyl-OPAHs and OPAH concentrations are frequently higher than parent-PAH concentrations. Furthermore, there are indications that OPAHs are more mobile in soil than PAHs. This calls for appropriate legal regulation of OPAH concentrations in soil.

Studio, simulazione e verifica sperimentale di tecniche di controllo per convertitori multilivello modulari

L’evoluzione dei componenti elettronici di potenza ed il conseguente sviluppo dei convertitori statici dell’energia elettrica hanno consentito di ottenere un’elevata efficienza energetica, sia nell’ambito degli azionamenti elettrici, sia nell’ambito della trasmissione e distribuzione dell’energia elettrica. L’efficienza energetica è una questione molto importante nell’attuale contesto storico, in quanto si sta facendo fronte ad una elevatissima richiesta di energia, sfruttando prevalentemente fonti di energia non rinnovabili. L’introduzione dei convertitori statici ha reso possibile un notevolissimo incremento dello sfruttamento delle fonti di energia rinnovabili: si pensi ad esempio agli inverter per impianti fotovoltaici o ai convertitori back to back per applicazioni eoliche. All’aumentare della potenza di un convertitore aumenta la sua tensione di esercizio: le limitazioni della tensione sopportabile dagli IGBT, che sono i componenti elettronici di potenza di più largo impiego nei convertitori statici, rendono necessarie modifiche strutturali per i convertitori nei casi in cui la tensione superi determinati valori. Tipicamente in media ed alta tensione si impiegano strutture multilivello. Esistono più tipi di configurazioni multilivello: nel presente lavoro è stato fatto un confronto tra le varie strutture esistenti e sono state valutate le possibilità offerte dall’architettura innovativa Modular Multilevel Converter, nota come MMC. Attualmente le strutture più diffuse sono la Diode Clamped e la Cascaded. La prima non è modulare, in quanto richiede un’apposita progettazione in relazione al numero di livelli di tensione. La seconda è modulare, ma richiede alimentazioni separate e indipendenti per ogni modulo. La struttura MMC è modulare e necessita di un’unica alimentazione per il bus DC, ma la presenza dei condensatori richiede particolare attenzione in fase di progettazione della tecnica di controllo, analogamente al caso del Diode Clamped. Un esempio di possibile utilizzo del convertitore MMC riguarda le trasmissioni HVDC, alle quali si sta dedicando un crescente interesse negli ultimi anni.

Development of a microgrid with renewable energy sources and electrochemical storage system integration

Beside the traditional paradigm of "centralized" power generation, a new concept of "distributed" generation is emerging, in which the same user becomes pro-sumer. During this transition, the Energy Storage Systems (ESS) can provide multiple services and features, which are necessary for a higher quality of the electrical system and for the optimization of non-programmable Renewable Energy Source (RES) power plants. A ESS prototype was designed, developed and integrated into a renewable energy production system in order to create a smart microgrid and consequently manage in an efficient and intelligent way the energy flow as a function of the power demand. The produced energy can be introduced into the grid, supplied to the load directly or stored in batteries. The microgrid is composed by a 7 kW wind turbine (WT) and a 17 kW photovoltaic (PV) plant are part of. The load is given by electrical utilities of a cheese factory. The ESS is composed by the following two subsystems, a Battery Energy Storage System (BESS) and a Power Control System (PCS). With the aim of sizing the ESS, a Remote Grid Analyzer (RGA) was designed, realized and connected to the wind turbine, photovoltaic plant and the switchboard. Afterwards, different electrochemical storage technologies were studied, and taking into account the load requirements present in the cheese factory, the most suitable solution was identified in the high temperatures salt Na-NiCl2 battery technology. The data acquisition from all electrical utilities provided a detailed load analysis, indicating the optimal storage size equal to a 30 kW battery system. Moreover a container was designed and realized to locate the BESS and PCS, meeting all the requirements and safety conditions. Furthermore, a smart control system was implemented in order to handle the different applications of the ESS, such as peak shaving or load levelling.