Preparação de um material de referência certificado para controle de agrotóxicos em hortifrutigranjeiros: estudo da estabilidade

Neste trabalho são apresentados os resultados dos estudos de estabilidade referentes à produção de um material de referência certificado. Foram avaliados níveis residuais de concentração dos agrotóxicos γ-HCH, fenitrotiona, clorpirifós e procimidona em polpa de tomate. A pasteurização e a irradiação gama foram empregadas à polpa de tomate, visando manter a integridade da amostra candidata a material de referência. A polpa foi preparada e dividida em duas partes. Cada parte foi fortificada com os referidos agrotóxicos na faixa de concentração de 0,1 a 0,2 mg.kg-1. Uma das partes foi submetida à pasteurização a 90 °C por 4 minutos e a outra parte foi irradiada com dose de 2,0 kGy depois de homogeneizada. A estabilidade e a incerteza da amostra, correspondente ao período de tempo avaliado, foram determinadas através da análise de regressão em conjunto com a ANOVA. Os resultados indicaram que ambos os procedimentos de preparo da amostra são adequados para a conservação da polpa de tomate fortificada com os quatro agrotóxicos, com vantagem para o tratamento por irradiação com a dose de 2,0 kGy.

Microparticles obtained by complex coacervation: influence of the type of reticulation and the drying process on the release of the core material

Microparticles obtained by complex coacervation were crosslinked with glutaraldehyde or with transglutaminase and dried using freeze drying or spray drying. Moist samples presented Encapsulation Efficiency (%EE) higher than 96%. The mean diameters ranged from 43.7 ± 3.4 to 96.4 ± 10.3 µm for moist samples, from 38.1 ± 5.36 to 65.2 ± 16.1 µm for dried samples, and from 62.5 ± 7.5 to 106.9 ± 26.1 µm for rehydrated microparticles. The integrity of the particles without crosslinking was maintained when freeze drying was used. After spray drying, only crosslinked samples were able to maintain the wall integrity. Microparticles had a round shape and in the case of dried samples rugged walls apparently without cracks were observed. Core distribution inside the particles was multinuclear and homogeneous and core release was evaluated using anhydrous ethanol. Moist particles crosslinked with glutaraldehyde at the concentration of 1.0 mM.g-1 protein (ptn), were more efficient with respect to the core retention compared to 0.1 mM.g-1 ptn or those crosslinked with transglutaminase (10 U.g-1 ptn). The drying processes had a strong influence on the core release profile reducing the amount released to all dry samples

Presence of central nervous system tissues as bovine spongiform encephalopathy specified risk material in Turkish raw meat ball (cig kofte)

Abstract Bovine Spongiform Encephalopathy (BSE) is a virulent disease which may infect by affecting the central nervous system (CNS) tissues in cattle and causes degeneration in nerves. Central nervous system tissues such as brain and spinal cord which are classified as specified risk materials (SRMs) are regarded to be main source of infection. The contamination of the meat with the specific risk materials (SRMs) can occur in phases of slaughter, fragmentation of carcass and processing. This study was conducted in order to investigate the existence of CNS tissues in raw meat ball (cig kofte) which is commonly consumed in the Southeastern Region of Turkey, particularly in Şanlıurfa. For this purpose, 145 samples of raw meat ball were tested. The enzyme-linked immunosorbent assay (ELISA) kits (Ridascreen risk material 10/5, R-biofarm GmbH) which determine glial fibrillary acidic protein (GFAP) as determinant were used. As a result of the analyses, positivity was detected in 21 of totally 145 samples of raw meat ball (14.48%). 6 (4.14%) of the samples gave low level of positivity (≥ 0.1 standard absorbance), 10 (6.90%) gave medium level of positivity (>0.2 standard absorbance) and 5 (3.45%) gave high level of positivity (≥0.5 standard absorbance). As a consequence, meats are contaminated in any phase of both slaughter and meat production even if accidentally. Regarding this matter, necessary measures should be taken and hygiene rules should be applied.

Simulation and material calibration of ultra high strength steel (UHSS) S960 welded joint under static tensile test utilizing finite element method (FEM)

The aim of this work was to calibrate the material properties including strength and strain values for different material zones of ultra-high strength steel (UHSS) welded joints under monotonic static loading. The UHSS is heat sensitive and softens by heat due to welding, the affected zone is heat affected zone (HAZ). In this regard, cylindrical specimens were cut out from welded joints of Strenx® 960 MC and Strenx® Tube 960 MH, were examined by tensile test. The hardness values of specimens’ cross section were measured. Using correlations between hardness and strength, initial material properties were obtained. The same size specimen with different zones of material same as real specimen were created and defined in finite element method (FEM) software with commercial brand Abaqus 6.14-1. The loading and boundary conditions were defined considering tensile test values. Using initial material properties made of hardness-strength correlations (true stress-strain values) as Abaqus main input, FEM is utilized to simulate the tensile test process. By comparing FEM Abaqus results with measured results of tensile test, initial material properties will be revised and reused as software input to be fully calibrated in such a way that FEM results and tensile test results deviate minimum. Two type of different S960 were used including 960 MC plates, and structural hollow section 960 MH X-joint. The joint is welded by BöhlerTM X96 filler material. In welded joints, typically the following zones appear: Weld (WEL), Heat affected zone (HAZ) coarse grained (HCG) and fine grained (HFG), annealed zone, and base material (BaM). Results showed that: The HAZ zone is softened due to heat input while welding. For all the specimens, the softened zone’s strength is decreased and makes it a weakest zone where fracture happens while loading. Stress concentration of a notched specimen can represent the properties of notched zone. The load-displacement diagram from FEM modeling matches with the experiments by the calibrated material properties by compromising two correlations of hardness and strength.

Characterization and Investigation on Material Compatibilities of Building Integrated Photovoltaic Module Components

Building Integrated Photovoltaics (BIPV) are considered as the future of photovoltaic (PV) technology. The advantage of BIPV system is its multi-functionality; they fulfil the functions of a building envelope with the added benefit of generating power by replacing the traditional roofing and façade materials with PV that generate power. In this thesis, different types of PV cells and modules have been described in detail with their efficiencies and usage trends in the last decade. The different BIPV products for roof and façade are discussed in detail giving several examples. The electricity generation potential of BIPV in selected countries is compared with their actual electricity consumption. Further, the avoided greenhouse gas (GHG) emissions associated with electricity generation from traditional sources and transportation and distribution (T&D) losses are calculated. The results illustrate huge savings in GHGs. In BIPV different types of façade and backsheets are used. In this thesis, selected backsheets and façade were characterized in terms of their surface structure identification using infrared spectroscopy (FTIR-ATR), scanning electron microscopy with energy dispersive X-ray (SEM-EDX) and physical characterization using surface energy measurements. By using FTIR-ATR, surface polymeric materials were identified and with SEM-EDX, identification of the surface elements was possible. Surface energy measurements were useful in finding the adhesives and knowing the surface energies of the various backsheets and façade. The strength of adhesion between the facade and backsheets was studied using peel test. Four different types of adhesives were used to study the fracture pattern and peel tests values to identify the most suitable adhesive. It was found out that pretreatment increased the adhesive strength significantly.

Chemical changes in biomass during torrefaction

Torrefaction is moderate thermal treatment (~200-300 °C) of biomass in an inert atmosphere. The torrefied fuel offers advantages to traditional biomass, such as higher heating value, reduced hydrophilic nature, increased its resistance to biological decay, and improved grindability. These factors could, for instance, lead to better handling and storage of biomass and increased use of biomass in pulverized combustors. In this work, we look at several aspects of changes in the biomass during torrefaction. We investigate the fate of carboxylic groups during torrefaction and its dependency to equilibrium moisture content. The changes in the wood components including carbohydrates, lignin, extractable materials and ashforming matters are also studied. And at last, the effect of K on torrefaction is investigated and then modeled. In biomass, carboxylic sites are partially responsible for its hydrophilic characteristic. These sites are degraded to varying extents during torrefaction. In this work, methylene blue sorption and potentiometric titration were applied to measure the concentration of carboxylic groups in torrefied spruce wood. The results from both methods were applicable and the values agreed well. A decrease in the equilibrium moisture content at different humidity was also measured for the torrefied wood samples, which is in good agreement with the decrease in carboxylic group contents. Thus, both methods offer a means of directly measuring the decomposition of carboxylic groups in biomass during torrefaction as a valuable parameter in evaluating the extent of torrefaction. This provides new information to the chemical changes occurring during torrefaction. The effect of torrefaction temperature on the chemistry of birch wood was investigated. The samples were from a pilot plant at Energy research Center of the Netherlands (ECN). And in that way they were representative of industrially produced samples. Sugar analysis was applied to analyze the hemicellulose and cellulose content during torrefaction. The results show a significant degradation of hemicellulose already at 240 °C, while cellulose degradation becomes significant above 270 °C torrefaction. Several methods including Klason lignin method, solid state NMR and Py-GC-MS analyses were applied to measure the changes in lignin during torrefaction. The changes in the ratio of phenyl, guaiacyl and syringyl units show that lignin degrades already at 240 °C to a small extent. To investigate the changes in the extractives from acetone extraction during torrefaction, gravimetric method, HP-SEC and GC-FID followed by GC-MS analysis were performed. The content of acetone-extractable material increases already at 240 °C torrefaction through the degradation of carbohydrate and lignin. The molecular weight of the acetone-extractable material decreases with increasing the torrefaction temperature. The formation of some valuable materials like syringaresinol or vanillin is also observed which is important from biorefinery perspective. To investigate the change in the chemical association of ash-forming elements in birch wood during torrefaction, chemical fractionation was performed on the original and torrefied birch samples. These results give a first understanding of the changes in the association of ashforming elements during torrefaction. The most significant changes can be seen in the distribution of calcium, magnesium and manganese, with some change in water solubility seen in potassium. These changes may in part be due to the destruction of carboxylic groups. In addition to some changes in water and acid solubility of phosphorous, a clear decrease in the concentration of both chlorine and sulfur was observed. This would be a significant additional benefit for the combustion of torrefied biomass. Another objective of this work is studying the impact of organically bound K, Na, Ca and Mn on mass loss of biomass during torrefaction. These elements were of interest because they have been shown to be catalytically active in solid fuels during pyrolysis and/or gasification. The biomasses were first acid washed to remove the ash-forming matters and then organic sites were doped with K, Na, Ca or Mn. The results show that K and Na bound to organic sites can significantly increase the mass loss during torrefaction. It is also seen that Mn bound to organic sites increases the mass loss and Ca addition does not influence the mass loss rate on torrefaction. This increase in mass loss during torrefaction with alkali addition is unlike what has been found in the case of pyrolysis where alkali addition resulted in a reduced mass loss. These results are important for the future operation of torrefaction plants, which will likely be designed to handle various biomasses with significantly different contents of K. The results imply that shorter retention times are possible for high K-containing biomasses. The mass loss of spruce wood with different content of K was modeled using a two-step reaction model based on four kinetic rate constants. The results show that it is possible to model the mass loss of spruce wood doped with different levels of K using the same activation energies but different pre-exponential factors for the rate constants. Three of the pre-exponential factors increased linearly with increasing K content, while one of the preexponential factors decreased with increasing K content. Therefore, a new torrefaction model was formulated using the hemicellulose and cellulose content and K content. The new torrefaction model was validated against the mass loss during the torrefaction of aspen, miscanthus, straw and bark. There is good agreement between the model and the experimental data for the other biomasses, except bark. For bark, the mass loss of acetone extractable material is also needed to be taken into account. The new model can describe the kinetics of mass loss during torrefaction of different types of biomass. This is important for considering fuel flexibility in torrefaction plants.

Effect of Material Recycling on the Feasibility of Solid Recovered Fuel Fired Power Plant

This master’s thesis examines the effects of increased material recycling on different waste-to-energy concepts. With background study and a developed techno-economic computational method the feasibility of chosen scenarios with different combinations of mechanical treatment and waste firing technologies can be evaluated. The background study covers the waste scene of Finland, and potential market areas Poland and France. Calculated cases concentrate on municipal solid waste treatment in the Finnish operational environment. The chosen methodology to approach the objectives is techno-economic feasibility assessment. It combines calculation methods of literature and practical engineering to define the material and energy balances in chosen scenarios. The calculation results together with other operational and financial data can be concluded to net present values compared between the scenarios. For the comparison, four scenarios, most vital and alternative between each other, are established. The baseline scenario is grate firing of source separated mixed municipal solid waste. Second scenario is fluidized bed combustion of solid recovered fuel produced in mechanical treatment process with metal separation. Third scenario combines a biomaterial separation process to the solid recovered fuels preparation and in the last scenario plastics are separated in addition to the previous operations. The results indicated that the mechanical treatment scenarios still need to overcome some problems to become feasible. Problems are related to profitability, residue disposal and technical reliability. Many uncertainties are also related to the data gathered over waste characteristics, technical performance and markets. With legislative support and development of further processing technologies and markets of the recycled materials the scenarios with biomaterial and plastic separation may operate feasibly in the future.

Publikationsstatistik Okatalogiserat material 1991-

Vapaakappalekartuntaan perustuva tilasto Suomessa julkaistuista pienpainatteista, julisteista, toimintakertomuksista ja kunnallisista julkaisuista vuodesta 1991 lähtien. Pienpainatelehdet sisältyvät tilastoon vuodesta 2014 lähtien

Publication Statistics Uncatalogued material 1991-

Vapaakappalekartuntaan perustuva tilasto Suomessa julkaistuista pienpainatteista, julisteista, toimintakertomuksista ja kunnallisista julkaisuista vuodesta 1991 lähtien. Pienpainatelehdet sisältyvät tilastoon vuodesta 2014 lähtien

Design and Material Selection of High-Speed Rotating Electrical Machines

The increasing emphasis on energy efficiency is starting to yield results in the reduction in greenhouse gas emissions; however, the effort is still far from sufficient. Therefore, new technical solutions that will enhance the efficiency of power generation systems are required to maintain the sustainable growth rate, without spoiling the environment. A reduction in greenhouse gas emissions is only possible with new low-carbon technologies, which enable high efficiencies. The role of the rotating electrical machine development is significant in the reduction of global emissions. A high proportion of the produced and consumed electrical energy is related to electrical machines. One of the technical solutions that enables high system efficiency on both the energy production and consumption sides is high-speed electrical machines. This type of electrical machines has a high system overall efficiency, a small footprint, and a high power density compared with conventional machines. Therefore, high-speed electrical machines are favoured by the manufacturers producing, for example, microturbines, compressors, gas compression applications, and air blowers. High-speed machine technology is challenging from the design point of view, and a lot of research is in progress both in academia and industry regarding the solution development. The solid technical basis is of importance in order to make an impact in the industry considering the climate change. This work describes the multidisciplinary design principles and material development in high-speed electrical machines. First, high-speed permanent magnet synchronous machines with six slots, two poles, and tooth-coil windings are discussed in this doctoral dissertation. These machines have unique features, which help in solving rotordynamic problems and reducing the manufacturing costs. Second, the materials for the high-speed machines are discussed in this work. The materials are among the key limiting factors in electrical machines, and to overcome this limit, an in-depth analysis of the material properties and behavior is required. Moreover, high-speed machines are sometimes operating in a harsh environment because they need to be as close as possible to the rotating tool and fully exploit their advantages. This sets extra requirements for the materials applied.

Resolución N° 134 ¿Cuál es el control de legalidad de la Cámara de Comercio de Bogotá frente a las actas sobre las cuales se alega falsedad ideológica o material? - la denominación del acta no determina la naturaleza de la reunión

Servicios registrales

Resolución N° 18 ¿En que consiste la presunción de autenticidad en materia de actas contentivas de decisiones sociales? ¿Es la Cámara de Comercio competente para evaluar la validez material de un acta presentada para registro?

Servicios registrales

Resolución N° 113 ¿Cuál es el alcance del control de legalidad de las cámaras de comercio respecto de los nombramientos? ¿Qué naturaleza tiene dicho control- es formal o material? ¿Es competente la Cámara respecto del control sobre presuntas falsedades del documento presentado para registro?

Servicios registrales