Waste Stream Investigation from Perspective of Changing Waste Legislation at Green Sand Foundries

The update of the Finnish legislation concerning waste was unavoidable, to comply with the European Union (EU) requirements defined in the EU-Directive on Waste. The new waste law updates were enacted into the Finnish legislation on the 11.03.2011 and targeted for applicability by the 11.03.2012. This thesis investigates the implications of the new amendments to the waste legislation from the perspective of green sand foundries. The investigations are conducted by comparing two of Componenta’s green sand foundries and evaluating their waste streams. Additionally, the impacts of legislation amendments are critiqued on their environmental and economic aspects. The study’s comparison of waste fractions at the two foundries reveals that sand is dominant in absolute tonnage and costs. The increments of waste taxes forces foundries to focus on waste management, recycling and disposing. The new legislation’s promotion of material efficiency, also guides foundries towards the prevention of waste. A potential preventive measure is to regenerate waste sand resulting to cost savings on both raw-materials and waste management. However, the lack of absolute targets for waste prevention or recycling rates discourages the interests towards creating or adopting new technologies and methods for the waste handling.

Mathematical models to describe the volumetric shrinkage rate of red beans during drying

The present study aimed to determine the volumetric shrinkage rate of bean (Phaseolus vulgaris L.) seeds during air-drying under different conditions of air, temperature and relative humidity, and to adjust several mathematical models to the empiric values observed, and select the one that best represents the phenomenon. Six mathematical models were adjusted to the experimental values to represent the phenomenon. It was determined the degree of adjustment of each model from the value of the coefficient of determination, the behavior of the distribution of the residuals, and the magnitude of the average relative and estimated errors. The rate of volumetric shrinkage that occurred in bean seeds during drying is between 25 and 37%. It basically depends on the final moisture content, regardless of the air conditions during drying. The Modified Bala & Woods' model best represented the process.

Mathematical model to estimate of the deterioration of wooden poles in contact with soil used in rural areas

In São Paulo State, mainly in rural areas, the utilization of wooden poles is observed for different purposes. In this context, wood in contact with the ground presents faster deterioration, which is generally associated to environmental factors and, especially to the presence of fungi and insects. With the use of mathematical models, the useful life of wooden structures can be predicted by obtaining "climatic indexes" to indicate, comparatively among the areas studied, which have more or less tendency to fungi and insects attacks. In this work, by using climatological data of several cities at São Paulo State, a simplified mathematical model was obtained to measure the aggressiveness of the wood in contact with the soil.

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.

Mathematical modeling applied to the growth of tilapia in net cages in the sub middle of the São Francisco river

This study aimed to apply mathematical models to the growth of Nile tilapia (Oreochromis niloticus) reared in net cages in the lower São Francisco basin and choose the model(s) that best represents the conditions of rearing for the region. Nonlinear models of Brody, Bertalanffy, Logistic, Gompertz, and Richards were tested. The models were adjusted to the series of weight for age according to the methods of Gauss, Newton, Gradiente and Marquardt. It was used the procedure "NLIN" of the System SAS® (2003) to obtain estimates of the parameters from the available data. The best adjustment of the data were performed by the Bertalanffy, Gompertz and Logistic models which are equivalent to explain the growth of the animals up to 270 days of rearing. From the commercial point of view, it is recommended that commercialization of tilapia from at least 600 g, which is estimated in the Bertalanffy, Gompertz and Logistic models for creating over 183, 181 and 184 days, and up to 1 Kg of mass , it is suggested the suspension of the rearing up to 244, 244 and 243 days, respectively.

Mathematical simulation parameters for drying of cassava starch pellets

Based on experimental tests, it was obtained the equations for drying, equilibrium moisture content, latent heat of vaporization of water contained in the product and the equation of specific heat of cassava starch pellets, essential parameters for realizing modeling and mathematical simulation of mechanical drying of cassava starch for a new technique proposed, consisting of preformed by pelleting and subsequent artificial drying of starch pellets. Drying tests were conducted in an experimental chamber by varying the air temperature, relative humidity, air velocity and product load. The specific heat of starch was determined by differential scanning calorimetry. The generated equations were validated through regression analysis, finding an appropriate correlation of the data, which indicates that by using these equations, can accurately model and simulate the drying process of cassava starch pellets.

Investigation of the two-photon induced fluorescence in Rb vapour excited by Ti:Sapphire femtosecond laser pulses

In this work we report the observation of the blue visible fluorescence at 420 nm in rubidium vapour as a result of two-photon absorption excited by femtosecond laser pulses 790 nm. After experimental investigation of the spa-tial and spectral characteristics of the obtained emission we can claim that mechanism of this coherent fluorescence at 420 nm was not caused by ampli-fied spontaneous emission, but represents the nondegenerate four-wave mixing. As a probable outcome of this investigation an opportunity of creation an ultrafast all-optical switcher might appear.

Cognitive Auditory Evoked Potentials in Investigation of Hearing Discrimination

Preattentive perception of occasional deviating stimuli in the stream of standard stimuli can be recorded with cognitive event-related potential (ERP) mismatch negativity (MMN). The earlier detection of stimuli at the auditory cortex can be examined with N1 and P2 ERPs. The MMN recording does not require co-operation, it correlates with perceptual threshold, and even complex sounds can be used as stimuli. The aim of this study was to examine different aspects that should be considered when measuring discrimination of hearing with ERPs. The MMN was found to be stimulusintensity- dependent. As the intensity of sine wave stimuli was increased from 40 to 80 dB HL, MMN mean amplitudes increased. The effect of stimulus frequency on the MMN was studied so that the pitch difference would be equal in each stimulus block according to the psychophysiological mel scale or the difference limen of frequency (DLF). However, the blocks differed from each other. The contralateral white noise masking (50 dB EML) was found to attenuate the MMN amplitude when the right ear was stimulated. The N1 amplitude was attenuated and, in contrast, P2 amplitude was not affected by contralateral white noise masking. The perception and production of vowels by four postlingually deafened patients with a cochlear implant were studied. The MMN response could be elicited in the patient with the best vowel perception abilities. The results of the studies show that concerning the MMN recordings, the stimulus parameters and recording procedure design have a great influence on the results.

Serological investigation and PCR in detection of pathogenic leptospires in snakes

Detection of Leptospira by PCR had not yet been described in snakes. This study investigated, by microscopic agglutination test (MAT) and PCR, the presence of antibodies to Leptospira spp. and Leptospira spp., respectively, in venomous and non-venomous wildlife and captivity snakes. All snakes were divided into three groups to be compared: Group 1 (wildlife snakes - WS); Group 2 (snakes in intensive captivity - IC), and Group 3 (collective semi-extensive captivity -CC). Of the 147 snakes studied, 52 (35.4%) were positive for leptospirosis by MAT, 8 (15.4%) belonging to Group 1 (WS), 34 (65.4%) to Group 2 (IC) and 10 (19.2%) to Group 3 (CC). Jararaca (Bothrops jararaca) presented the highest average titer (66.7%, N=22/33) among the three group studied, and Hardjo prajtino was the most prevalent serovar (88.5%, N=46/52), with titers varying from 100 to 3200. Leptospira interrogans was revealed by PCR in kidney and liver of caiçaca (Bothrops moojeni) and jararaca-pintada (Bothrops pauloensis), showing 100% and 93% identity respectively. Future studies should be carried out for better understanding of the role of snakes as a reservoir of Leptospira in nature.

Mathematical modeling of laboratory scale three-phase fixed bed reactors

Detta arbete fokuserar på modellering av katalytiska gas-vätskereaktioner som genomförs i kontinuerliga packade bäddar. Katalyserade gas-vätskereaktioner hör till de mest typiska reaktionerna i kemisk industri; därför behandlas här packade bäddreaktorer som ett av de populäraste alternativen, då kontinuerlig drift eftersträvas. Tack vare en stor katalysatormängd per volym har de en kompakt struktur, separering av katalysatorn behövs inte och genom en professionell design kan den mest fördelaktiga strömningsbilden upprätthållas i reaktorn. Packade bäddreaktorer är attraktiva p.g.a. lägre investerings- och driftskostnader. Även om packade bäddar används intensivt i industri, är det mycket utmanande att modellera. Detta beror på att tre faser samexisterar och systemets geometri är komplicerad. Existensen av flera reaktioner gör den matematiska modelleringen även mera krävande. Många förenklingar blir därmed nödvändiga. Modellerna involverar typiskt flera parametrar som skall justeras på basis av experimentella data. I detta arbete studerades fem olika reaktionssystem. Systemen hade studerats experimentellt i vårt laboratorium med målet att nå en hög produktivitet och selektivitet genom ett optimalt val av katalysatorer och driftsbetingelser. Hydrering av citral, dekarboxylering av fettsyror, direkt syntes av väteperoxid samt hydrering av sockermonomererna glukos och arabinos användes som exempelsystem. Även om dessa system hade mycket gemensamt, hade de också unika egenskaper och krävde därför en skräddarsydd matematisk behandling. Citralhydrering var ett system med en dominerande huvudreaktion som producerar citronellal och citronellol som huvudprodukter. Produkterna används som en citrondoftande komponent i parfymer, tvålar och tvättmedel samt som plattform-kemikalier. Dekarboxylering av stearinsyra var ett specialfall, för vilket en reaktionsväg för produktion av långkedjade kolväten utgående från fettsyror söktes. En synnerligen hög produktselektivitet var karakteristisk för detta system. Även processuppskalning modellerades för dekarboxylerings-reaktionen. Direkt syntes av väteperoxid hade som målsättning att framta en förenklad process att producera väteperoxid genom att låta upplöst väte och syre reagera direkt i ett lämpligt lösningsmedel på en aktiv fast katalysator. I detta system förekommer tre bireaktioner, vilka ger vatten som oönskad produkt. Alla dessa tre reaktioner modellerades matematiskt med hjälp av dynamiska massbalanser. Målet med hydrering av glukos och arabinos är att framställa produkter med en hög förädlingsgrad, nämligen sockeralkoholer, genom katalytisk hydrering. För dessa två system löstes ämnesmängd- och energibalanserna simultant för att evaluera effekter inne i porösa katalysatorpartiklar. Impulsbalanser som bestämmer strömningsbetingelser inne i en kemisk reaktor, ersattes i alla modelleringsstudier med semi-empiriska korrelationsuttryck för vätskans volymandel och tryckförlust och med axiell dispersionsmodell för beskrivning av omblandningseffekter. Genom att justera modellens parametrar kunde reaktorns beteende beskrivas väl. Alla experiment var genomförda i laboratorieskala. En stor mängd av kopplade effekter samexisterade: reaktionskinetik inklusive adsorption, katalysatordeaktivering, mass- och värmeöverföring samt strömningsrelaterade effekter. En del av dessa effekter kunde studeras separat (t.ex. dispersionseffekter och bireaktioner). Inverkan av vissa fenomen kunde ibland minimeras genom en noggrann planering av experimenten. På detta sätt kunde förenklingar i modellerna bättre motiveras. Alla system som studerades var industriellt relevanta. Utveckling av nya, förenklade produktionsteknologier för existerande kemiska komponenter eller nya komponenter är ett gigantiskt uppdrag. Studierna som presenterades här fokuserade på en av den teknisk-vetenskapliga utfärdens första etapper.

Mathematical modeling of level of anaesthesia from EEG measurements

Problem of modeling of anaesthesia depth level is studied in this Master Thesis. It applies analysis of EEG signals with nonlinear dynamics theory and further classification of obtained values. The main stages of this study are the following: data preprocessing; calculation of optimal embedding parameters for phase space reconstruction; obtaining reconstructed phase portraits of each EEG signal; formation of the feature set to characterise obtained phase portraits; classification of four different anaesthesia levels basing on previously estimated features. Classification was performed with: Linear and quadratic Discriminant Analysis, k Nearest Neighbours method and online clustering. In addition, this work provides overview of existing approaches to anaesthesia depth monitoring, description of basic concepts of nonlinear dynamics theory used in this Master Thesis and comparative analysis of several different classification methods.

A modified contour error controller for a high speed XY table

This article deals with a contour error controller (CEC) applied in a high speed biaxial table. It works simultaneously with the table axes controllers, helping them. In the early stages of the investigation, it was observed that its main problem is imprecision when tracking non-linear contours at high speeds. The objectives of this work are to show that this problem is caused by the lack of exactness of the contour error mathematical model and to propose modifications in it. An additional term is included, resulting in a more accurate value of the contour error, enabling the use of this type of motion controller at higher feedrate. The response results from simulated and experimental tests are compared with those of common PID and non-corrected CEC in order to analyse the effectiveness of this controller over the system. The main conclusions are that the proposed contour error mathematical model is simple, accurate, almost insensible to the feedrate and that a 20:1 reduction of the integral absolute contour error is possible.

An experimental investigation of the effects of nozzle ellipticity on the flow structure of co-flow jet diffusion flames

The flow structure of cold and ignited jets issuing into a co-flowing air stream was experimentally studied using a laser Doppler velocimeter. Methane was employed as the jet fluid discharging from circular and elliptic nozzles with aspect ratios varying from 1.29 to 1.60. The diameter of the circular nozzle was 4.6 mm and the elliptic nozzles had approximately the same exit area as that of the circular nozzle. These non-circular nozzles were employed in order to increase the stability of attached jet diffusion flames. The time-averaged velocity and r.m.s. value of the velocity fluctuation in the streamwise and transverse directions were measured over the range of co-flowing stream velocities corresponding to different modes of flame blowout that are identified as either lifted or attached flames. On the basis of these measurements, attempts were made to explain the existence of an apparent optimum aspect ratio for the blowout of attached flames observed at higher values of co-flowing stream velocities. The insensitivity of the blowout limits of lifted flames to nozzle geometry observed in our previous work at low co-flowing stream velocities was also explained. Measurements of the fuel concentration at the jet centerline indicated that the mixing process was enhanced with the 1.38 aspect ratio jet compared with the 1.60 aspect ratio jet. On the basis of the obtained experimental data, it was suggested that the higher blowout limits of attached flames for an elliptic jet of 1.38 aspect ratio was due to higher entrainment rates.