991 resultados para release paper
Resumo:
Aquest treball es basa en les pràctiques realitzades dins del marc del Màster en Envelliment Actiu de la Universitat de Vic. L’objectiu d’aquestes pràctiques era doble: per una banda, aprofundir en el coneixement del rol del psicogerontòleg en un centre sociosanitari d’atenció a la gent gran i, per l’altra, elaborar, aplicar i avaluar una intervenció per fomentar l’envelliment actiu. És a dir, es pretenia donar cobertura a les dues grans àrees d’intervenció a les quals ha de fer front el psicogerontòleg en l’actualitat, com veurem més endavant, i que són: l’atenció a la dependència i la promoció de l’envelliment actiu, tenint en compte que aquesta darrera suposa la prevenció de la malaltia i la discapacitat i la maximització del benestar i la qualitat de vida en la vellesa.
Resumo:
The transformation of a traditional pulp mill into an integrated forest biorefinery utilizing wood-derived biomass presents a promising opportunity for enterprise revival of the pulp and paper industry by offering new sources of revenue and significantly improved industry profitability. One proposed next generation process step for an integrated forest biorefinery is the extraction of hemicelluloses, allowing the co-production of pulp and ethanol or chemicals. The extraction of hemicelluloses, however, will likely have downstream effects on pulp quality. In the literature survey an overview of the integrated forest biorefinery and possible next generation technologies implementable in such facility were reviewed. Moreover, some hemicellulose extraction methods suitable for the co-production of pulp and hemicellulose products were looked into in more detail. Also, an overview on the significance of pulp’s hemicellulose content on papermaking properties of pulp fibers was made. In the literature it is stated that the hemicellulose content of pulp affects on many papermaking properties of pulp fibers, hornification and paper strength properties in particular. In the experimental part the goal was to investigate what effects alkaline hemicellulose extraction after bleaching has on the papermaking properties of birch Kraft pulp. It was discovered that tested pulps, normal and hemi-poor birch Kraft pulp, were different in many ways regarding to pulp properties. Differences were observed in both physical and chemical characteristics. Furthermore, clear distinctions were seen in tested paper properties, especially in strength properties, between the handsheets made from hemi-poor or normal birch Kraft pulp. Hemi-poor and normal birch Kraft pulps were also compared as a raw material of laboratory made copy paper. Based on this comparison, usage of hemi-poor birch pulp as the raw material of copy paper does not drastically deteriorate its quality.
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This study has been made for specific paper production line at an international forest industry company in Finland. The main purpose for the study was a need to examine the current situation of the customer knowledge and its’ sharing at case production line, recognize the problems in it and finally, find out the improvement actions. The study is composed of theoretical and empirical parts. In theoretical part, knowledge management and information sharing in addition to customer knowledge management are presented. Empirical data from case production line was collected by using survey questionnaires. The results are analyzed in discussion and conclusions and finally, study ends with summary which includes recommendations. Based on the study, the amount and quality of customer knowledge and gaining and transferring the customer knowledge were found as the main challenges. The proposed solutions were discovered from moving towards more dynamic operating environment and in the area of customer knowledge management, especially from the communities of creation.
Resumo:
In recent times of global turmoil, the need for uncertainty management has become ever momentous. The need for enhanced foresight especially concerns capital-intensive industries, which need to commit their resources and assets with long-term planning horizons. Scenario planning has been acknowledged to have many virtues - and limitations - concerning the mapping of the future and illustrating the alternative development paths. The present study has been initiated to address both the need of improved foresight in two capital-intensive industries, i.e. the paper and steel industries and the imperfections in the current scenario practice. The research problem has been approached by engendering a problem-solving vehicle, which combines, e.g. elements of generic scenario process, face-to-face group support methods, deductive scenario reasoning and causal mapping into a fully integrated scenario process. The process, called the SAGES scenario framework, has been empirically tested by creating alternative futures for two capital-intensive industries, i.e. the paper and steel industries. Three scenarios for each industry have been engendered together with the identification of the key megatrends, the most important foreign investment determinants, key future drivers and leading indicators for the materialisation of the scenarios. The empirical results revealed a two-fold outlook for the paper industry, while the steel industry future was seen as much more positive. The research found support for utilising group support systems in scenario and strategic planning context with some limitations. Key perceived benefits include high time-efficiency, productivity and lower resource-intensiveness. Group support also seems to enhance participant satisfaction, encourage innovative thinking and provide the users with personalised qualitative scenarios.
Resumo:
In the paper machine, it is not a desired feature for the boundary layer flows in the fabric and the roll surfaces to travel into the closing nips, creating overpressure. In this thesis, the aerodynamic behavior of the grooved roll and smooth rolls is compared in order to understand the nip flow phenomena, which is the main reason why vacuum and grooved roll constructions are designed. A common method to remove the boundary layer flow from the closing nip is to use the vacuum roll construction. The downside of the use of vacuum rolls is high operational costs due to pressure losses in the vacuum roll shell. The deep grooved roll has the same goal, to create a pressure difference over the paper web and keep the paper attached to the roll or fabric surface in the drying pocket of the paper machine. A literature review revealed that the aerodynamic functionality of the grooved roll is not very well known. In this thesis, the aerodynamic functionality of the grooved roll in interaction with a permeable or impermeable wall is studied by varying the groove properties. Computational fluid dynamics simulations are utilized as the research tool. The simulations have been performed with commercial fluid dynamics software, ANSYS Fluent. Simulation results made with 3- and 2-dimensional fluid dynamics models are compared to laboratory scale measurements. The measurements have been made with a grooved roll simulator designed for the research. The variables in the comparison are the paper or fabric wrap angle, surface velocities, groove geometry and wall permeability. Present-day computational and modeling resources limit grooved roll fluid dynamics simulations in the paper machine scale. Based on the analysis of the aerodynamic functionality of the grooved roll, a grooved roll simulation tool is proposed. The smooth roll simulations show that the closing nip pressure does not depend on the length of boundary layer development. The surface velocity increase affects the pressure distribution in the closing and opening nips. The 3D grooved roll model reveals the aerodynamic functionality of the grooved roll. With the optimal groove size it is possible to avoid closing nip overpressure and keep the web attached to the fabric surface in the area of the wrap angle. The groove flow friction and minor losses play a different role when the wrap angle is changed. The proposed 2D grooved roll simulation tool is able to replicate the grooved aerodynamic behavior with reasonable accuracy. A small wrap angle predicts the pressure distribution correctly with the chosen approach for calculating the groove friction losses. With a large wrap angle, the groove friction loss shows too large pressure gradients, and the way of calculating the air flow friction losses in the groove has to be reconsidered. The aerodynamic functionality of the grooved roll is based on minor and viscous losses in the closing and opening nips as well as in the grooves. The proposed 2D grooved roll model is a simplification in order to reduce computational and modeling efforts. The simulation tool makes it possible to simulate complex paper machine constructions in the paper machine scale. In order to use the grooved roll as a replacement for the vacuum roll, the grooved roll properties have to be considered on the basis of the web handling application.
Resumo:
The spread of sociocultural focuses and critical literacy studies, which offer an holistic perspective on communicative skills, has reached our country at a time when the commonest environment for writing is the internet, and information technologies have transformed writing with new channels, genres, forms of preparation and languages. Thanks to these changes, educational programmes now include new concepts of literacy related to knowledge and the use of digital environments. This paper explores the impact of introducing these new communicative environments to teaching written expression at secondary level and puts forward some ideas to link learning how to write to present communicative contexts and established practices. Without forgetting the achievements of recent decades, we need to bring about a series of changes to bring new learned writing practices to class and leave behind others we had championed as necessary when the goal was to move beyond exclusively linguistic or grammatical approaches
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In this paper, the effects of acrylamide (AAm), methylcellulose (MC) contents, pH and ionic strength on kinetic, network and hydrophilic properties of polyacrylamide and methylcellulose hydrogels were investigated. The hydrogels were characterized by evaluating of network [average molecular weight between crosslinks (M C), crosslink density (q) and the number of elastically effective chains (Ve)], and kinetic parameters [diffusional exponent (n), diffusion constant (k) and diffusion coefficient (D)]. Such properties were controlled by adjusting of the AAm, MC contents, pH and ionic strength factors. Due to high hydrophilicity and fast water-uptake, the PAAm-MC hydrogels can be considered as materials for potential applications in agricultural fields, mainly in controlled release of water or pesticides.
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Industrial hazardous wastes must receive appropriate treatment to ensure a safe disposal to humans and environment. One of the techniques adopted for this purpose is the stabilization/solidification in polymer matrices. This paper evaluated the use of recycled polyethylene terephthalate as an incorporation matrix of incinerator ash. The polymer and the ash were submitted to an extrusion process in different percentages. The final product was evaluated through thermal and leaching tests and the leachate extracts constituents were determinated by atomic absorption spectrophotometry. The results showed a reduction in the release of substances up to 99% by mass for the conditions used.
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In this paper we describe the preparation poly (L-lactide) (PLA) nanocapsules as a drug delivery system for the local anesthetic benzocaine. The characterization and in vitro release properties of the system were investigated. The characterization results showed a polydispersity index of 0.14, an average diameter of 190.1± 3 nm, zeta potential of -38.5 mV and an entrapment efficiency of 73%. The release profile of Benzocaine loaded in PLA nanocapsules showed a significant different behavior than that of the pure anesthetic in solution. This study is important to characterize a drug release system using benzocaine for application in pain treatment.
Resumo:
This work describes the development and validation of a dissolution test for 50 mg losartan potassium capsules using HPLC and UV spectrophotometry. A 2(4) full factorial design was carried out to optimize dissolution conditions and potassium phosphate buffer, pH 6.8 as dissolution medium, basket as apparatus at the stirring speed of 50 rpm and time of 30 min were considered adequate. Both dissolution procedure and analytical methods were validated and a statistical analysis showed that there are no significant differences between HPLC and spectrophotometry. Since there is no official monograph, this dissolution test could be applied for quality control routine.
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The aims of this study were to formulate calcium-alginate beads containing glibenclamide, characterize the resulting microparticles, evaluate the release characteristics of this type of delivery system in an in vitro dissolution test, and compare it with two commercially available trademarks (Daonil® and Glibetab®). We obtained glibenclamide loaded calcium-alginate beads with a rough surface and a particle size between 150-200 µm. For the in vitro dissolution test Daonil® at 45 min showed a Q > 70%, whereas Glibetab® and glibenclamide calcium-alginate beads a Q < 70%; in spite of that glibenclamide calcium-alginate beads showed significant release properties.
Resumo:
In this paper, we describe the preparation of alginate nanoparticles as a delivery system for the herbicide clomazone. Two different methods were investigated and characterized by size distribution, zeta potencial, pH and in vitro release. The alginate/AOT nanoparticles had higher rates of association of the herbicide clomazone than alginate/chitosan nanoparticles. Clomazone release profile, showed a significant difference in release behavior of pure herbicide in solution when compared with herbicide loaded in both alginate nanoparticles. This study is important to construct a biodegradable release system using herbicide for later release into more specific targets, avoiding contamination of environmental matrices.
Resumo:
This work describes the development and validation of a dissolution test for 60 mg of diltiazem hydrochloride in immediate release capsules. The best dissolution in vitro profile was achieved using potassium phosphate buffer at pH 6.8 as the dissolution medium and paddle as the apparatus at 50 rpm. The drug concentrations in the dissolution media were determined by UV spectrophotometry and HPLC and a statistical analysis revealed that there were significant differences between HPLC and spectrophotometry. This study illustrates the importance of an official method for the dissolution test, since there is no official monograph for diltiazem hydrochloride in capsules.
Resumo:
The purpose of this study was to improve PM7’s basis weight CD profile in Stora Enso’s Berghuizer mill and to search mechanical defects which affect to the formation of the basis weight CD profile. In the theoretical part PM7’s structure was presented and the formation of the basis weight and caliper CD profiles was examined as well as disturbances which are affecting to the formation. The function of the control system was scrutinised for the side of CD profiles as well as the formation of the measured CD profiles. Tuning of the control system was examined through the response model and filtering. Specification of the response model and filtering was explained and how to determine 2sigma statistical number. In the end of the theoretical part ATPA hardware and a new profile browser were introduced. In the experimental part focus was in the beginning to search and remove mechanical defects which are affecting to CD profiles. The next step was to verify the reliability of the online measurements, to study the stability of the basis weight CD profile and to find out so called fingerprint, a basis weight CD profile which is unique for each paper machine. New response model and filtering value for basis weight CD profile was determined by bump tests. After a follow up period the affect of the new response model and filtering was analysed.
Resumo:
Nanoparticles were produced by solvent emulsification evaporation method with the following characteristics: nanometric size (238 ± 3 nm), narrow polydispersity index (0.11), negative zeta potential (-15.1 mV), good yield of the process (73 ± 1.5%), excellent encapsulation efficiency (81.3 ± 4.2%) and spherical shape. X-rays diffraction demonstrated the loss of drug crystallinity after encapsulation; however, the profile of the diffractograms of the poly-ε-caprolactone (PCL) nanoparticles was kept. Differential scanning calorimetry thermograms, correspondingly, exhibited the loss of drug melting peak and the increasing of the melting point of the PCL nanoparticles, evidencing an interaction drug-polymer. Naproxen release was low and sustained obeying the Higuchi´s kinetic. The results show that nanoparticles are promising sustained release system to the naproxen.