Dissertations / Theses: 'Pulp'

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Kuhn, Reinaldo. "On site measurements of kraft pulp pump system efficiency." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/656.

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With increasing energy costs and competitive pressures, interest has increased in surveying installed pumps for potential energy savings. Field pump efficiency tests are required to assess pumping performance and help to identify improvement opportunities. This work concerns the on-site measurements of pulp-suspension pumping efficiency. This involves the measurement of pump head, flow rate and power consumption. Provided that consistent flow measurements are available, it is possible to reliably and non-invasively measure actual pump system efficiencies in pulp suspension flow, with a minimum process disturbance. As part of a most appropriate measurement-procedure study, four portable nonintrusive flow meters were evaluated on site for pulp suspension flow. The Fast Fourier Transform Doppler was found to be the most suitable for a pulp mill pump survey. Efficiency measurements were performed on six pump systems with motors between 100 and 700 HP. It is shown that as-installed pump efficiency can be used to help predict the degradation of the pump and also its effect on the pumping system’s operation. A system approach analysis was performed in each case, which can be effective in assessing system performance and finding potential enhancements. The use of variable speed drives allows the operating point to move along the system curve, requiring less energy to drive the pump. VSD of larger motors are expensive and their profitability compared to other modification alternatives should always be carefully checked by calculations based on accurate on site measurements and life cycle costs. Finally, in this survey of six pump systems, significant potential savings of around 30% of present power consumption were found.

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Flores, Basauri Shirley Pilar, Cavero Diana Andrea Rivera, Vásquez Roxana Vanessa Romero, and Lefoncio Jesús Kiler Vaca. "Coffee Pulp." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2017. http://hdl.handle.net/10757/621819.

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El Perú es uno de los principales productores de café de gran calidad en Sudamérica, actualmente cuenta con cuatro ciudades de mayor producción, entre ellos encontramos: Junín, Amazonas, Cajamarca y San Martín. Asimismo, a lo largo del tiempo el grano de café es lo que más se ha valorado, dejando de lado a su cascara, como un simple desperdicio y obviando su importante valor nutricional. Coffee Pulp, es una harina elaborada en base a la cascara de café. Se caracteriza por ser un producto saludable y especialmente libre de gluten (proteína que se encuentra en alimentos procesados del trigo). Esta nueva propuesta busca mejorar la calidad de vida de nuestros clientes, ofreciendo diferentes beneficios nutritivos. Su proceso de producción se realizará con la más alta calidad desde el proceso de selección de sus principales proveedores, excelentes condiciones de almacenamiento, hasta el empaquetado que permite conservar todos los beneficios, el sabor y la frescura. Nuestra propuesta surge de la apreciación de un nicho de mercado insatisfecho, debido a la necesidad existente en el consumo de productos saludables y libres de gluten en el Perú. Además, cada vez aumenta más la tendencia del cuidado de salud en el ámbito alimenticio, algo que actualmente toma mayor relevancia en nuestro país. Nuestro público objetivo son personas que se inclinan por mantener una alimentación saludable, o en especial aquellas personas que son intolerantes o sensibles al gluten, cuyo estilo de vida corresponde a la de los sofisticados, perteneciendo al NSE A y B que comprende los distritos de San Isidro, Miraflores, San Borja, Surco, La Molina, Jesús María, Lince, Pueblo Libre, Magdalena y San Miguel y cuyas edades comprenden entre los 25 a 54 años. A través del plan de actividades estratégicas y de marketing diseñadas para nuestro producto, aplicaremos la estrategia de diferenciación, buscando crear ante nuestros clientes una percepción de producto único y diferente en el mercado, provocando así una mayor lealtad a la marca. Pues de esta manera, nace nuestro proyecto, planteándonos en atender un público objetivo innovador en el consumo de alimentos saludables, a quienes les gusta seguir tendencias y son asiduos consumidores de productos “light”. En el presente trabajo mostramos a detalle cada análisis con sus respectivos resultados, que durante todo el ciclo se vino desarrollando con la finalidad de lograr la mayor rentabilidad y viabilidad del proyecto, siguiendo los consejos y recomendaciones de nuestros asesores del curso de Proyecto Empresarial. En cuanto al análisis financiero, se espera en el tercer año obtener una utilidad neta de S/ 126,185 Las ventas crecerán progresivamente año tras año en un 20%. La inversión requerida es de S/ 70,379 monto que será financiado el 30% y el 70% será aporte de los propios accionistas. El VAN FCLD calculado es de 246,405 con una TIR de 63%. Asimismo, los inversionistas obtienen un VAN de S/ 241,263 con un nivel de inversión de S/ 49,265 y una TIR de 67 %. Y por último el periodo de retorno de la inversión es de 2 años y medio. Todos estos resultados de rentabilidad mencionados sobre el capital invertido hacen viable el proyecto.
Perú is one of the main high quality coffee producers in South America. Currently, there are four cities of vast production, amongst them we find: Junín, Amazonas, Cajamarca and San Martín. Likewise, along the time, the coffee bean is the most valued, leaving aside its husk, as a simple waste and obviating its important nutritional value. Coffee Pulp is flour made based on coffee husk. It is characterized by being a healthy product and especially free of gluten (protein that is in processed foods of the wheat). This new proposal seeks to improve the quality of life of our customers, offering different nutritional benefits. Its production process will be carried out with the highest quality since the selection process of its main suppliers, excellent conditions of storage, until the packaging that allows to preserve all benefits, flavour and freshness. Our proposal arises from the appreciation of an unsatisfied market niche, due to the existing need in the consumption of healthy and gluten-free products in Peru. Additionally, at present more are the people who prefer to eat healthy in our country. Our target audience is people who are inclined to maintain a healthy diet, or especially those people who are intolerant or sensitive to gluten, whose lifestyle corresponds to the sophisticated, belonging to the NSE A and B comprising the districts of San Isidro, Miraflores, San Borja, Surco, La Molina, Jesus Maria, Lince, Pueblo Libre, Magdalena and San Miguel and whose ages are between 25 and 54 years old. Through the plan of strategic and marketing activities designed for our product, we will apply the strategy of differentiation, seeking to create in our customers a perception of unique and different product in the market, in order to create a greater loyalty with the brand. In this way, our project was born, focusing on serving an innovative target audience in the consumption of healthy foods, who like to follow trends and are regular consumers of "light" products. In the present work we show each analysis with its respective results in detail. During the whole cycle, it was developed with the purpose of achieving the highest profitability and viability of the project, following the advice and recommendations of our consultants of the Business Project course. Regarding the financial analysis, it is expected to obtain a net profit of S/ 126,185 in the third year. Sales will grow 20% progressively year by year. The required investment is S/ 70,379 and this will be financed 30% by a finantial institution and 70% will be contributed by the shareholders. The calculated FCAN VNA is 246,405 with a TIR 63%. Similarly, investors obtain a VNA of S/ 241,263 with an investment level of S/ 49,265 and a TIR 67%. Finally, the return period of the investment is two and half years. All of these profitability results mentioned on the invested capital make the project feasible.
Trabajo de Investigación

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Bennington, Chad Patrick Joseph. "Mixing pulp suspensions." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28622.

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Initiation and maintenance of motion within a pulp suspension is necessary for effective mixing. This requires imposition of forces greater than the network strength and depends on suspension rheology once motion begins. As pulp suspensions display non-Newtonian and solid-like behaviour, studies were conducted using profiled rotors which imposed stress within the body of suspensions contained in cylindrical devices. A concentric cylinder device capable of high torques (85 N-m) and high rotational speeds (524 rad/s) was built to study pulp suspension dynamic behaviour. Most work used a profiled rotor 0.1 m in diameter with baffled housings 0.13 and 0.22 m in diamter. The yield stress of low consistency pulp suspensions were measured with a Haake RV12 Ro-tovisco concentric cylinder viscometer. Semi-bleached kraft pulp was used throughout the study. Some tests were made with stone groundwood and thermomechanical pulps. Yield stress measurements were made for nylon and Spectra-900 fibre suspensions. The yield stress of pulp suspensions, ty, have been measured and correlated with mass concentration (Cm) and volumetric concentration (Cv) over the range 0.4 ≤ Cm(%) ≤ 33. It was found that because of increasing gas content that correlations developed using the mass concentration were inaccurate above approximately 20% Cm. Correlations developed using the volumetric concentration were accurate over the full range tested. For a West-Coast semi-bleached kraft pulp, ty(Pa) = 1.40CV(%)²ֹ⁷². Once rotor motion was initiated, pulp suspensions exhibited two distinct regimes of behaviour. The first was a tangential-cavity regime in which predominantly tangential motion grew to fill the chamber as shear rate increased. When motion reached the outer housing wall a flow transition occurred, likely triggered by flow interaction with the housing baffles. The subsequent post-transition regime was characterized by radial and axial flow that effectively mixed the suspension on both the macroscale and fibre-scale. The flow transition appeared to be what earlier workers reported as the onset of "fluidization". During tangential-cavity flow, phase segregation occurred. Gas present in the suspension collected around the rotor and reduced momentum transfer from the rotor to the suspension. This caused the torque for the pulp suspension to fall below that for water at the same rotational speed, and the cessation of flow development in the chamber. If sufficient momentum transfer was attained to initiate post-transition flow, the chamber contents became effectively mixed. The torque could still fall below that of water depending on the effective density of the suspension in the rotor vicinity.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate

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Dou, Xiaoli. "Elucidating the pulp properties that influence the ability of enzymes to facilitate the conversion of hardwood Kraft pulp to dissolving-grade pulps." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/60229.

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Dissolving pulp is characterized by its high cellulose/low hemicellulose content, minor amounts of residual lignin/extractives, high brightness and a uniform molecular weight distribution. Dissolving pulp can be produced through acid sulfite cooking or alkaline Kraft cooking. However, due to issues with chemical recovery and pollution, the predominant pulping process has globally shifted to the Kraft process. Kraft pulps retain hemicellulose and high molecular weight cellulose, which are undesirable for dissolving pulps. Therefore, steps such as prehydrolysis (PHK) and cold caustic extraction (CCE) aimed at removing hemicellulose and decreasing cellulose molecular weight are typically employed. However, these processes are chemically intensive, non-specific and pose operational challenges for mills. The use of enzymes (hemicellulases and cellulases) is one potential alternative to chemical methods of facilitating mill conversion due to the high specificity of enzymes and their ability to function under more benign conditions. Initially, xylanase and oxalic acid treatments were assessed for their potential to convert Kraft-to-dissolving pulp. It was apparent that the accessibility of hemicellulose and cellulose to chemical or enzymatic reagents was critical. Compared to oxalic acid, enzymes were more specific in removing hemicellulose while boosting cellulose reactivity. Model substrates, varying in their hemicellulose accessibility and cellulose properties, were used to assess the influence of various pulp characteristics on enzymatic pulp modification. The influence of pulp characteristics imparted by PHK and CCE on the ease of enzymatic modification was also assessed. It appeared that CCE negatively impacted the accessibility of hemicellulose due to the solubilisation of low molecular weight carbohydrates fragments which acted as “spacers” between cellulose microfibrils, preventing fibril aggregation. Lowering the acidity of the prehydrolysis or the alkalinity of Kraft pulping conditions increased the ease of enzymatic removal of the hemicellulose, presumably by increasing hemicellulose accessibility. Separating the fibres into various size fractions indicated that the shorter fibres within the Kraft pulp were more susceptible to enzymatic modification, likely due to their increased porosity. It was apparent that Kraft pulping conditions played a significant role in governing enzyme accessibility to the various pulp carbohydrates and thus the potential of using enzymes to enhance dissolving pulp production and properties.
Forestry, Faculty of
Graduate

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Spender, Jonathan. "Photostabilization of High-Yield Pulps Reaction of Thiols and Quinones with Pulp." Fogler Library, University of Maine, 2001. http://www.library.umaine.edu/theses/pdf/SpenderJ2001.pdf.

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Cadete, Sonia Marisa Silva. "Enzymatic upgrading of eucalypt paper-grade kraft pulp within dissolving pulp production." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/16089.

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Mestrado em Biotecnologia - Biotecnologia Industrial e Ambiental
Dissolving-grade pulps are commonly used for the production of cellulose derivatives and regenerated cellulose. High cellulose content, low content of non-cellulosic material, high brightness, a uniform molecular weight distribution and high cellulose reactivity are the key features that determine the quality of a dissolving pulp. The first part of this work was an optimization study regarding the application of selected enzymes in different stages of a new purification process recently developed in Novozymes for purifying an eucalypt Kraft pulp into dissolving pulp, as an alternative to the pre-hydrolysis kraft (PHK) process. In addition, a viscosity reduction was achieved by cellulase (endoglucanase) treatment in the beginning of the sequence, while the GH11 and GH10 xylanases contributed to boost the brightness of the final pulp. The second part of the work aimed at exploring different auxiliary enzyme activities together with a key xylanase towards further removal of recalcitrant hemicelluloses from a partially bleached Eucalypt Kraft pulp. The resistant fraction (ca. 6% xylan in pulp) was not hydrolysable by the different combinations of enzymes tested. Production of a dissolving pulp was successful when using a cold caustic extraction (CCE) stage in the end of the sequence O-X-DHCE-X-HCE-D-CCE. The application of enzymes improved process efficiency. The main requirements for the production of a dissolving pulp (suitable for viscose making) were fulfilled: 2,7% residual xylan, 92,4% of brightness, a viscosity within the values of a commercial dissolving pulp and increased reactivity.
Pastas solúveis são normalmente usadas para a produção de derivativos de celulose e celulose regenerada. Alguns dos parâmetros que determinam a qualidade de uma pasta solúvel são: um elevado teor de celulose, baixo teor de material nãocelulósico, elevada brancura, uma distribuição uniforme de pesos moleculares e elevada reactividade da celulose. Na primeira parte deste trabalho, fez-se um estudo de optimização aplicando enzimas, previamente seleccionadas, em diferentes fases de um novo processo de purificação desenvolvido na Novozymes da pasta de eucalipto Kraft em celulose solúvel, como uma alternativa ao processo convencional de pré-hidrólise kraft. Além da purificação, a aplicação de celulases (endoglucanase) no início da sequência possibilitou uma diminuição da viscosidade, enquanto que a aplicação de xilanases das famílias GH11 e GH10 contribuíram também para o aumento da brancura da pasta final. A segunda parte deste trabalho teve como objectivo explorar várias actividades enzimáticas auxiliares conjuntamente com a melhor GH11 xilanase identifcada, de modo a promover a remoção das hemiceluloses mais recalciterantes de uma pasta Kraft de Eucalipto parcialmente branqueada. Todas as combinações das enzimas testadas resultaram numa fracção resistente de xilana residual (ca. 6% na pasta) que não foi possível hidrolisar. A produção de uma pasta solúvel foi possível usando um estágio de extracção alkalino a frio (CCE) no fim de uma sequência composta pelos seguintes estágios: O-X-D-HCE-X-HCE-D-CCE. A aplicação de enzimas melhorou a eficiencia do processo. Com esta sequência,os principais requisitos para a produção de uma pasta solúvel (adequada para producao de viscose) foram cumpridos: 2,7% de xilana residual, 92,4% de brancura, uma viscosidade dentro dos valores de uma pasta solúvel comercial e elevada reactividade.

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Dyhr, Kurt. "Zeolites in pulp bleaching." Licentiate thesis, Luleå tekniska universitet, 1998. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26600.

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Tang, Wei. "Chemimechanical pulp from reed." Thèse, Université du Québec à Trois-Rivières, 1992. http://depot-e.uqtr.ca/5368/1/000597745.pdf.

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Dissanayaka, Waruna Lakmal. "Synergistic effects of dental pulp stem cells and endothelial cells in pulp regeneration." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/197085.

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Regeneration of the tissues to replace diseased, missing and traumatized dentin/pulp requires combining the recent progress in stem cell and tissue engineering research. Dental pulp stem cells (DPSCs) are considered as a promising population of cells in regenerative dentistry and shown to be able to produce dentin/pulp-like tissues following implantation in-vivo. Securing a good blood supply is critical in pulp regeneration, however, this is a challenging task due to the unique structure of the tooth, the anatomy of which permits only a microcirculatory system via a very small apical opening (<0.3-1mm). This limitation raises the need to develop novel methods to enhance angiogenesis during pulp regeneration. It was shown that DPSCs reside in the microvasculature region of the dental pulp and interact with perivascular cells. Therefore, endothelial cells could be a major source of modulators of pulp-dentin development and angiogenesis. If a pulp tissue substitute with pre-formed endothelial network could be engineered in-vitro, it would not only gain rapid anastomosis with host vasculature but also regulate DPSC function in pulp regeneration. In this study, for the first time, synergistic effects of DPSCs and human umbilical vein endothelial cells (HUVECs) on osteo/odontogenic differentiation and angiogenesis were investigated using two-dimensional and three-dimensional direct co-culture systems. Furthermore, the potential of three-dimensional DPSC constructs prevascularized with HUVECs in dental pulp regeneration in-vivo was exmined. HUVECs promoted odonto/osteogenic differentiation of DPSCs in direct two-dimensional co-cultures in-vitro. Further, addition of DPSCs stabilized the pre-existing vessel-like structures formed by HUVECs and increased the longevity of these structures on matrigel in-vitro. Using two different systems, scaffold-free self-assembling microtissue spheroids and peptide hydrogel scaffold, the interactions of DPSCs and HUVECs in three-dimensional cultures were investigated. The results demonstrated that DPSCs can self assemble into three-dimensional microtissue spheroids when cultured alone or with HUVECs. DPSCs promoted survival and vascular structure formation by HUVECs both in scaffold-free microtissue spheroids and peptide hydrogel scaffold. In contrast, HUVECs, when cultured alone, neither formed vascular structures nor survived in either of the 3D systems. The latter phenomenon was attributable to vascular endothelial growth factor secreted by DPSCs, a major factor responsible for endothelial function. Co-cultures also showed enhanced odonto/osteogenic differentiation in both three-dimensional microtissue spheroid and peptide hydrogel scaffold systems. Following implantation of tooth-root fragments filled with three-dimensional DPSC constructs into the subcutaneous space of immunodefficient mice, vascularised pulp-like tissue was regenerated within the root canals. Compared to DPSC-only group, DPSC/HUVEC co-culture groups showed higher vascularisation, extracellular matrix formation and mineralization in regenerated tissue. More importantly, HUVEC-lined vascular lumens were observed in regenerated tissues suggesting the successful integration of in-vitro formed pre-vascular structures to the host vasculature. In summary, the findings suggest that DPSCs and HUVECs display significant synergy during odonto/osteogenic differentiation and angiogenesis when co-cultured either in two-dimensional or three-dimensional culture systems. Unravelling these fundamental behavioural patterns of DPSCs provides novel insights into the process of pulp regeneration, leading to new avenues for more effective therapies in regenerative endodontics.
published_or_final_version
Dentistry
Doctoral
Doctor of Philosophy

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Killough, Simon Anthony. "The role of the pulp fibroblast in neurogenic inflammation of human dental pulp." Thesis, Queen's University Belfast, 2007. https://pure.qub.ac.uk/portal/en/theses/the-role-of-the-pulp-fibroblast-in-neurogenic-inflammation-of-human-dental-pulp(44f7b320-7369-4dca-8447-c35b11e629b4).html.

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Dental pulp inflamm'ation has major clinical significance. Recent research has suggested that the fibroblast has a role as driver of the inflammatory response. The term 'neurogenic inflammation' describes the contribution of the nervous system to local inflammatory responses and is thought to play an active and dynamic role in modulating pulpal inflammation. The function of the dental pulp fibroblast in the regulation of the neurogenic response to inflammation is unknown. This thesis presents a series of experimental studies investigating the role of the fibroblast in this aspect of inflammation. Cultured human dental' pulp fibroblasts populations were used in this study using a variety of in vitro techniques. The first part of the thesis involved the detection of substance P (SP) and neuropeptide Y (NPY) receptors, NK-I and NPY-YI respectively. Results demonstrated the expression of these receptors in pulp fibroblasts both at the mRNA and protein levels and their expression levels were regulated by cytokines and neuropeptides. The second part investigated the production of neuropeptides by pulp fibroblasts lnd results showed SP expression both at the mRNA and protein levels. Tissue levels of SP and NPY were quantified and compared in healthy and carious pulps, sho~ing increased expression during dental caries. The final section examined the responsiveness of pulp fibroblasts to SP and NPY. It was shown that pulp fibroblasts increased in proliferation in response to SP and had the ability to differentiate into odontoblasts. Furthermore, pulp fibroblasts expressed osteoprotegerin (OPO) and receptor activator of nuclear factor KB ligand (RANKL) indicating a role in 'clastic' activity. The present work demonstrated a potential role of the dental pulp fibroblast in the neurogenic inflammatory response with respect to SP and NPY, leading to a clearer understanding of their role in inflammation.

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Armas, Huamani Ruth Tafat, Ames César Augusto Castañeda, Davila Julio Joaquín Heriberto Domenack, Moquillaza Johana Katheryne Rojas, and Pillaca Luis Enrique Sulca. "Proyecto fruit pulp “aplicación para la venta de pulpa de fruta a domicilio”." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/653104.

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Fruit Pulp es una empresa que se dedicará a la producción, embolsado, comercialización y distribución de pulpa de fruta en presentaciones de 250 y 500 gramos respectivamente con seis distintos sabores. El producto está dirigido a personas de los NSE A, B, y la distribución será con nuestros propios medios. Lima ha tenido un crecimiento constante de consumidores que cuidan su salud y se alimentan sanamente, sobre todo en estos tiempos de pandemia la buena alimentación con frutas que suministran vitaminas y antioxidantes ayuda a mantener un cuerpo sano y vigoroso, nuestro producto se va a vender al consumidor final por medio de una aplicación y pagina web que va ayudar a que las personas lo encuentren con facilidad. Nos orientamos principalmente a ofrecer un producto de calidad, utilizando una materia prima de primera calidad y además de una entrega rápida de los insumos para poder mantener la producción constante. Nuestro enfoque va dirigido a distritos que fueron elegidos por una serie de análisis de diversos factores entre los cuales destacan los costos de alquiler, distancia entre distritos que son el mercado objetivo y cercanía de los trabajadores de la empresa. Finalmente se especifica el análisis financiero de la empresa donde muestra la inversión inicial con la que se debe de empezar la empresa, flujos de cajas, proyección de ventas, gastos operativos y demás con un periodo de proyección de cinco años, donde se puede apreciar que la idea es viable para poder invertir.
Fruit Pulp is a company that will be dedicated to the production, bagging, marketing, and distribution of fruit pulp in presentations of 250 and 500 grams respectively with six different flavors. The product is directed to people of the NSE A, B, and the distribution will be with our own means. Lima has had a constant growth of consumers who take care of their health and eat healthy, especially in these times of pandemic the good diet with fruits that supply vitamins and antioxidants helps to maintain a healthy and vigorous body, our product will be sold to the consumer final through an application and website that will help people find it easily. We are mainly focused on offering a quality product, using a first quality raw material and in addition to a quick delivery of the supplies in order to maintain constant production. Our approach is aimed at districts that were chosen by a series of analyzes of various factors, among which are rental costs, distance between districts that are the target market, and proximity of company workers. Finally, the financial analysis of the company is specified, where it shows the initial investment with which the company must start, cash flows, sales projection, operating expenses and others with a projection period of five years, where it can be seen that the idea is viable to be able to invest.
Trabajo de investigación

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Larsson, Carolina. "Sizing of different pulp qualities." Thesis, Karlstad University, Faculty of Technology and Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-1591.

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Edge wicking, i.e. in-plane wetting, is an important parameter for liquid packaging board products. Before filling of the products at the dairy the web is being sterilised with hydrogen peroxide (H2O2). A tube is shaped and cut into packages which mean that new surfaces are created. If a short stop occurs in the sterilising bath the raw edges exposed to H2O2 could absorb the liquid and when the package later is being filled this absorption could lead to tube burst. For the end products it is also important to prevent the liquid from penetrating the raw edges of the board in order to maintain the functionality and fresh look of the package.

To control edge wicking different kinds of internal hydrophobic sizing agents are used. Alkyl ketene dimer (AKD) is the most common size in neutral sizing and rosin in conjunction with alum is the traditional acidic sizing agent. AKD and rosin size are often used in combination (dual sizing) to make the board hydrophobic.

The objective of this work was to examine the effects of the sizing agents on different pulps in different dosages. The pulps used in the sheet preparation were unbleached kraft pulp as well as bleached and unbleached CTMP refined to different levels. Apart from varying the size dosages, the wet sheets were also pressed at different levels to vary the density. The major part of the study included dual sizing but a minor part also concerned mono sized sheets.

The parameters investigated on the laboratory sheets were STFI-Density, hydrogen peroxide edge wicking, pressurised edge wicking, lactic acid edge wicking (LA) and AKD and rosin size content.

In hydrogen peroxide edge wicking the amount of size was the central source of improved wick index. The retention was therefore of great significance for the results. The dual sized sheets were found to give least edge wicking, due to the synergy effect between AKD and alum rosin size. The kraft pulps gave sheets with satisfactory edge wicking even at the lowest size dosage (1 kg/t) while CTMP required a dosage of 4 kg/t to reach the same wick index.

To achieve acceptable pressurised edge wicking values the most important parameter was found to be the density of the sheets. The kraft pulp sheets gave the lowest edge penetration while the high freeness CTMP sheets did not give satisfactory penetration resistant even at the highest size dosage.

The edge wicking of lactic acid could be prevented by sizing with AKD only. Sheets made from mono sized sheets containing rosin size did not manage to avoid a large in-plane wetting of the board structure. Hence, dual sizing to improve the edge wicking of lactic acid is not necessary. The density was found not to be an important parameter in lactic acid edge wicking, all the pulps got equal edge wicking regardless of density. Retention above 1 kg/t AKD in sheets was enough to prevent penetration. Retention above 1.5 kg/t AKD in sheet did not improve the edge wicking any further.

No significant difference in sizeability between unbleached and bleached CTMP was observed.

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Illikainen, M. (Mirja). "Mechanisms of thermomechanical pulp refining." Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514289064.

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Abstract The objective of this thesis was to obtain new information about mechanisms of thermomechanical pulp refining in the inner area of a refiner disc gap by studying inter-fibre refining and by calculating the distribution of energy consumption in the refiner disc gap. The energy consumption of thermomechanical pulping process is very high although theoretically a small amount of energy is needed to create new fibre surfaces. Mechanisms of refining have been widely studied in order to understand the high energy consumption of the process, however, phenomena in the inner area of disc gap has had less attention. It is likely that this important position is causing high energy consumption due to the high residence time of pulp located there. The power distribution as a function of the refiner disc gap was calculated in this work. The calculation was based on mass and energy balances, as well as temperature and consistency profiles determined by mill trials. The power distribution was found to be dependent on segment geometry and the refining stage. However, in the first stage refiner with standard refiner segments, a notable amount of power was consumed in the inner area of the disc gap. Fibre-to-fibre refining is likely to be the most important mechanism in the inner area of disc gap from the point of view of energy consumption. In this work the inter-fibre refining was studied using equipment for shear and compression. Fibre-to-fibre refining was found to be an effective way to refine fibres from coarse pulp to separated, fibrillated and peeled fibres if frictional forces inside the compressed pulp were high enough. It was proposed that high energy of today’s thermomechanical pulping process could derive from too low frictional forces that heated pulp and evaporated water without any changes in fibre structure. The method to calculate power distribution and results of fibre-to-fibre refining experiments may give ideas for developing today’s thermomechanical pulp refiners’ or for developing totally new energy saving mechanical pulping processes.

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Kutacova, Pavla. "Enzymatic modification of kenaf pulp." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ33973.pdf.

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Zhang, Xiao Zhu. "Ozone bleaching of chemical pulp." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0014/NQ38356.pdf.

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Morgan, David Ellis. "Pulp literature : a re-evaluation /." Access via Murdoch University Digital Theses Project, 2002. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040820.122551.

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Ali, Omar Feroze. "Dynamic chlorination of kraft pulp." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75877.

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Chlorination of kraft black spruce pulp was studied in a fixed bed reactor. Breakthrough curves of the reactant chlorine and the products TOC, chloride and methanol were measured. The flow residence time distribution was determined by performing a stimulus response tracer experiment preceding chlorination of each pulp pad. The chlorine and methanol break-through curves were well described by a parallel plug flow model and instantaneous chlorine-lignin and first order chlorine-carbohydrates reactions. The representation of the residence time distribution by plug flow through segregated channels rather than by axial dispersed plug flow was confirmed by the effect of operating variables on the residence time distribution and by comparison with theory and numerical predictions. The good representation of the actual flow by the parallel plug flow model can be explained by poor radial mixing and a relatively large scale of variation in radial velocity. The latter is a direct consequence of the large aspect ratio of pulp fibers and their associated tendency to flocculate. This also explains why the dispersion in pulp pads is larger than in beds of regular shaped particles which have the same equivalent diameter as pulp fibers.
Chlorine-lignin and methanol-lignin stoichiometries were determined as a function of operating conditions. The chlorine-lignin stoichiometry is a function of mean residence time and temperature, but not of chlorine feed concentration. The values of the chlorine-lignin stoichiometry are lower than found for corresponding batch chlorination of softwood pulps. The methanol-lignin stoichiometry is not influenced by any of the operating variables. The methanol concentration in the effluent can be used as an indicator for the completion of the chlorine-lignin reaction. Pulp properties such as lignin content, kappa number and viscosity were measured at the end of an experiment. Maximum delignification in any channel is obtained at chlorine breakthrough. Recycling of reconcentrated spent filtrate did not hinder delignification rates. The reciprocal intrinsic viscosity is proportional to the chlorine charge on pulp. Higher pulp viscosities are obtained at lower temperatures and mean residence times and at higher chlorine feed concentrations for the same chlorine charge on pulp. Viscosity protection agents like chlorine dioxide are effective in dynamic chlorination.

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Poirier, Nicole A. "Displacement washing of wood pulp." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65442.

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19

Morgan, David Ellis. "Pulp literature: a re-evaluation." Thesis, Morgan, David Ellis (2003) Pulp literature: a re-evaluation. PhD thesis, Murdoch University, 2003. https://researchrepository.murdoch.edu.au/id/eprint/208/.

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The purpose of this dissertation is to redress the literary academy?s view of Pulp Literature as an inconsequential form, which does not merit serious contemplation, or artistic recognition. Although it is true that recent literary criticism has attempted to elevate the importance of Pulp by positing it as the natural postmodern 'other' to 'high' literature, the thesis demonstrates how this dichotomy has proven to be counter-productive to its aim. That is, although this theoretical approach does invite legitimate investigation of the form, many academics simply use this technique to reinforce their claims for the superiority of so-called 'canonic' texts. Therefore, rather than continuing along this downward path, this thesis focuses more on the subversive machinations of Pulp Literature as a social, economic, political, and theoretical force with its own strategies and agendas, opening with an investigation of the history of Pulp Literature as a cultural form. I argue that, from its very conception with the invention of the printing press in the fifteenth century, Pulp has always offered a radical alternative to the mainstream by providing a voice for the marginalised and the oppressed in the societies of the world. The thesis traces this political role as the aesthetic evolves into the new forms and technologies of a contemporary culture, where many academics still refuse to acknowledge Pulp as an important agent for the transmission of ideological views, and an impetus to instigate social change. The concluding arguments move away from the quantitative, to the more theoretically evaluative section of the thesis. This consists of a discussion of the conceptual boundaries surrounding the aesthetic of Pulp, broaching such subjects as literary evaluation, canonicity, and canon formation. This debate ultimately revolves around the question, 'if literary theorists cannot 'objectively' determine what literary 'quality' is, then how can we hope to define Pulp?' In an attempt to answer this question, the thesis juxtaposes the criteria of a number of literary theorists from this field of inquiry, namely, Thomas R. Whissen, Clive Bloom, Thomas J. Roberts, Harold Bloom, Andrew Calcutt and Richard Shephard, to formulate an aesthetic that is not only markedly different to their's, but more significantly, one which situates Pulp Literature at the head of the literary academic table.

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20

Morgan, David Ellis. "Pulp literature: a re-evaluation." Morgan, David Ellis (2003) Pulp literature: a re-evaluation. PhD thesis, Murdoch University, 2003. http://researchrepository.murdoch.edu.au/208/.

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The purpose of this dissertation is to redress the literary academy?s view of Pulp Literature as an inconsequential form, which does not merit serious contemplation, or artistic recognition. Although it is true that recent literary criticism has attempted to elevate the importance of Pulp by positing it as the natural postmodern 'other' to 'high' literature, the thesis demonstrates how this dichotomy has proven to be counter-productive to its aim. That is, although this theoretical approach does invite legitimate investigation of the form, many academics simply use this technique to reinforce their claims for the superiority of so-called 'canonic' texts. Therefore, rather than continuing along this downward path, this thesis focuses more on the subversive machinations of Pulp Literature as a social, economic, political, and theoretical force with its own strategies and agendas, opening with an investigation of the history of Pulp Literature as a cultural form. I argue that, from its very conception with the invention of the printing press in the fifteenth century, Pulp has always offered a radical alternative to the mainstream by providing a voice for the marginalised and the oppressed in the societies of the world. The thesis traces this political role as the aesthetic evolves into the new forms and technologies of a contemporary culture, where many academics still refuse to acknowledge Pulp as an important agent for the transmission of ideological views, and an impetus to instigate social change. The concluding arguments move away from the quantitative, to the more theoretically evaluative section of the thesis. This consists of a discussion of the conceptual boundaries surrounding the aesthetic of Pulp, broaching such subjects as literary evaluation, canonicity, and canon formation. This debate ultimately revolves around the question, 'if literary theorists cannot 'objectively' determine what literary 'quality' is, then how can we hope to define Pulp?' In an attempt to answer this question, the thesis juxtaposes the criteria of a number of literary theorists from this field of inquiry, namely, Thomas R. Whissen, Clive Bloom, Thomas J. Roberts, Harold Bloom, Andrew Calcutt and Richard Shephard, to formulate an aesthetic that is not only markedly different to their's, but more significantly, one which situates Pulp Literature at the head of the literary academic table.

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21

Morgan, David Ellis. "Pulp Literature: a Re-evalutation." Murdoch University, 2003. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040820.122551.

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The purpose of this dissertation is to redress the literary academys view of Pulp Literature as an inconsequential form, which does not merit serious contemplation, or artistic recognition. Although it is true that recent literary criticism has attempted to elevate the importance of Pulp by positing it as the natural postmodern other to high literature, the thesis demonstrates how this dichotomy has proven to be counter-productive to its aim. That is, although this theoretical approach does invite legitimate investigation of the form, many academics simply use this technique to reinforce their claims for the superiority of so-called canonic texts. Therefore, rather than continuing along this downward path, this thesis focuses more on the subversive machinations of Pulp Literature as a social, economic, political, and theoretical force with its own strategies and agendas, opening with an investigation of the history of Pulp Literature as a cultural form. I argue that, from its very conception with the invention of the printing press in the fifteenth century, Pulp has always offered a radical alternative to the mainstream by providing a voice for the marginalised and the oppressed in the societies of the world. The thesis traces this political role as the aesthetic evolves into the new forms and technologies of a contemporary culture, where many academics still refuse to acknowledge Pulp as an important agent for the transmission of ideological views, and an impetus to instigate social change. The concluding arguments move away from the quantitative, to the more theoretically evaluative section of the thesis. This consists of a discussion of the conceptual boundaries surrounding the aesthetic of Pulp, broaching such subjects as literary evaluation, canonicity, and canon formation. This debate ultimately revolves around the question, if literary theorists cannot objectively determine what literary quality is, then how can we hope to define Pulp? In an attempt to answer this question, the thesis juxtaposes the criteria of a number of literary theorists from this field of inquiry, namely, Thomas R. Whissen, Clive Bloom, Thomas J. Roberts, Harold Bloom, Andrew Calcutt and Richard Shephard, to formulate an aesthetic that is not only markedly different to theirs, but more significantly, one which situates Pulp Literature at the head of the literary academic table.

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22

Karlsson, Hanna. "Strength Properties of Paper produced from Softwood Kraft Pulp : Pulp Mixture, Reinforcement and Sheet Stratification." Doctoral thesis, Karlstads universitet, Avdelningen för kemiteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-5612.

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For paper producers, an understanding of the development of strength properties in the paper is of uttermost importance. Strong papers are important operators both in the traditional paper industry as well as in new fields of application, such as fibre-based packaging, furniture and light-weight building material. In the work reported in this thesis, three approaches to increasing paper strength were addressed: mixing different pulps, multilayering and reinforcement with man-made fibres. In specific: The effects of mixing Swedish softwood kraft pulp with southern pine or with abaca (Musa Textilis) were investigated. Handsheets of a softwood kraft pulp with the addition of abaca fibres were made in a conventional sheet former. It was seen that the addition of abaca fibres increased the tearing resistance, fracture toughness, folding endurance and air permeance. Tensile strength, tensile stiffness and tensile energy absorption, however, decreased somewhat. Still it was possible to add up to about 60% abaca without any great loss in tensile strength. As an example, with the addition of 30% abaca, the tear index was increased by 36%, while the tensile index was decreased by 8%. To study the effect of stratification, a handsheet former for the production of stratified sheets, the LB Multilayer Handsheet Former was evaluated. The advantage of this sheet former is that it forms a stratified sheet at low consistency giving a good ply bond. It was shown to produce sheets with good formation and the uniformity, evaluated as the variation of paper properties, is retained at a fairly constant level when the number of layers in the stratified sheets is increased. The uniformity of the sheets produced in the LB Multilayer Handsheet Former is generally at the same level as of those produced in conventional sheet formers. The effects of placing southern pine and abaca in separate layers, rather than mixing them homogeneously with softwood pulp were studied. Homogeneous and stratified sheets composed of softwood and southern pine or softwood and abaca were produced in the LB Multilayer Handsheet Former. It was found that by stratifying a sheet, so that a pulp with a high tear index and a pulp with a high tensile index are placed in separate layers, it was possible to increase the tear index by approximately 25%, while the tensile index was decreased by 10-20%. Further, by mixing a pulp with less conformable fibres and no fines with a pulp with more flexible fibres and fines, a synergy in tensile strength (greater strength than that predicted by linear mass fraction additivity) was obtained. The effects of stratifying sheets composed of softwood and abaca were compared to the effects of refining the softwood pulp. Homogeneous and stratified sheets composed of softwood with three different dewatering resistances and abaca were also produced in the LB Multilayer Handsheet Former. It was found that by stratifying the sheets the tear index was retained while the tensile index was increased by the refining. The effects of reinforcing softwood pulp of different dewatering resistances with man-made fibres with low bonding ability were also investigated. Man-made fibres (i.e. regenerated cellulose, polyester and glass fibres) were added in the amounts 1, 3, or 5 wt% to softwood pulp of three different dewatering resistances. It was found that with refining of a softwood pulp and subsequent addition of long fibres with low bonding ability the tensile-tear relationship can be shifted towards higher strength values. The bonding ability of the man-made fibres was evaluated by pull-out tests and the results indicated that, in relation to the fibre strength, regenerated cellulose (lyocell) was most firmly attached to the softwood network while the glass fibres were most loosely attached.

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23

Elahimehr, Ali. "Low consistency refining of mechanical pulp : the relationship between plate pattern, operational variables and pulp properties." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50745.

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In this dissertation we propose a framework to predict pulp properties of mean fibre length and freeness from low consistency (LC) refiner operating conditions and present correlations between those properties of pulp and hand sheet paper properties of tear, tensile and bulk. This framework is not new and was proposed by Luukkonen [1] however, studying the effect of plate pattern in this work based on the methodology presented in this dissertation is a novel approach. We accomplish this objective through the introduction of two geometrical parameters: Bar Interaction Length, BIL, and Bar Interaction Area, BIA. To do so, a comprehensive modelling of the geometry of disc refiner plates used in LC refining of mechanical pulp is done. We develop analytical and numerical models to estimate important geometrical parameters such as bar crossing area, leading edges of bar crossings and number of crossing points in a disc refiner with parallel distribution of bars. We will then use these models to predict pulp properties of mean fibre length and freeness from refiner operating conditions by running pilotscale refining trials of mechanical pulp over a wide range of plate pattern, rotational speed and gap size. From this stage, we present correlations between hand sheet paper properties of tear, tensile, bulk and pulp properties of freeness and fibre length. We also demonstrate a relationship between net power, plate pattern and refiner operating parameters such as plate gap and rotational speed based upon a classical dimensional analysis in which a reduced parameter space is related to each other through the use of statistical modelling.
Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate

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24

Ahlquist, Michael L. "On pulpal pain in man an experimental psychophysiological study /." Stockholm : Kongl. Carolinska Medico Chirurgiska Institutet, 1988. http://catalog.hathitrust.org/api/volumes/oclc/18998289.html.

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25

Bucchi, Morales María Cristina. "Experimental Approaches for Pulp Tissue Regeneration." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/668228.

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The aim of this PhD thesis was to study experimental approaches for revitalization of necrotic teeth. Revitalization, also known as regenerative endodontic procedures (REPs), is a relatively new treatment for necrotic teeth which tries to regenerate the dentine-pulp complex instead of obturating the root canal with biologically inert materials (root canal treatment). Until very recently, the most reliable option for the treatment of immature necrotic teeth was apexification followed by root canal treatment. However, endodontically treated teeth remain devitalized throughout the patient's lifetime and therefore defenceless to new caries lesions, as the absence of pulp implies the lack of tooth immune mechanisms. On the contrary, the regeneration of the dentine-pulp complex allows further root development and aims to recover the natural immune and secretory system of the pulp, making teeth more resistant to future lesions or traumatisms. The therapy was developed to treat necrotic immature teeth (i.e. those that have not completed their root development). Clinically, the outcomes can be considered successful since there is a resolution of the symptomatology, healing of the apical pathosis and further root development in most cases. However, histological analysis has demonstrated that the tissues formed after the therapy are reparative tissues – such as cementum-like tissue – instead of dentine, as well as an unorganized connective tissue, instead of pulp with its characteristic odontoblast layer. Currently, numerous efforts are being made to shed light on the clinical and biological aspects involved in the regeneration of pulp. Chapter 1: As previously said, evidence shows that no dentine but reparative tissues (cementum-like tissue) are responsible for the root development after regenerative endodontics. As cementum is less hard and less elastic than dentine, the question arises whether a root with apposition of cementum can endure mechanical stress similarly to roots completed by dentine. Thus, one of the objectives of this thesis was to compare the biomechanical performance of cementum- and dentine-reinforced teeth, and therefore to evaluate the biomechanical advantages of dentine regeneration after regenerative endodontics. We developted a finite element model of cementum- and dentinereinformed teeth and studied the stress distribution after the simulation of biting, trauma and orthodontic movement. The results showed that apposition of hard tissue (whether cementum or dentine) after REPs reduces mechanical stress on 17 immature teeth and, more important, that the formation of dentine is advantageous because it, unlike cementum, facilitates an even stress distribution throughout the root. As far as we know, ours was the first study showing the biomechanical advantages of dentine regeneration. Chapter 2: Odontoblasts are post-mitotic cells that secrete dentine. The isolation and culture of odontoblasts may open numerous possibilities to study this cell type under standardized conditions, shedding light on their roles in dentine formation, immune defence and transmission of external stimuli. We evaluated different protocols of enzymatic treatment to isolate primary odontoblasts from human molars. The results showed that, regardless of the enzymatic solution used, odontoblasts in culture did not remain viable after 24 h. Additionally, we identified increased expression of nestin (NE), bone sialoprotein (BSP) and dentine matrix acidic phosphoprotein 1 (DMP1) in the odontoblast layer compared to pulp fibroblasts. Though primary odontoblasts can still not be cultivated after isolation, characteristic genes were identified to differentiate odontoblasts from pulp fibroblasts. Chapter 3: We analysed the effects of autologous platelet concentrates (APCs) in the clinical and histological outcomes of the therapy and the different clinical protocols clinically used through systematic reviews. The results indicated that APCs improve the clinical and radiographic outcomes of regenerative endodontics since the teeth treated with APCs achieved significantly better thickening of the dentine walls and root lengthening. However, true regeneration of pulp was not achieved with the addition of platelet concentrates, which only stimulated tissue repair. Additionally, most of the studies did not follow a standard clinical protocol for regenerative endodontic therapy and used irritant and intracanal medicaments that are cytotoxic and affect the differentiation and adherence of the stem cells. Chapters 4 and 5: As will be mentioned in detail, a small apical foramen acts as a physical barrier that hinders tissue ingrowth into the root canal and therefore reduces the possibility of revitalization of mature teeth. We studied different methods for apical foramen enlargement of mature teeth as a basis to apply it in a further animal study. We analysed manual instrumentation at different working lengths and apicoectomy on extracted human teeth and in situ teeth. We concluded that apicoectomy is not an effective technique for apical foramen enlargement and therefore should not be used for that purpose. Instrumentation 18 0.5mm beyond the apex resulted in the most effective technique. Later, we performed an animal study and evaluated pulp tissue regeneration/repair in mature teeth and the differentiation of the stem cells from the periapical tissues into odontoblast-like cells by adding preameloblast-conditioned medium. Preameloblast-conditioned medium was applied in pulpectomized ferret canines, whose apical foramina were enlarged using the previously developed method. We observed vascularized connective tissue occupying the apical third of the canal space in 50% of the teeth, showing the potential of revascularization of mature teeth. However, no odontoblast-like cells were observed showing that in vivo odontoblast-like differentiation of stem cells is still not possible with the tested technique. Chapter 6: Finally, we present here the preliminary data of characterization and odontoblast-like differentiation of amnion epithelial cells. Human amnion epithelial cells (hAECs) express pluripotent stem cell markers and have been proven to differentiate in cells of the three embryologic layers. However, as far as we know, these are the first experiments that have proved the potential of odontoblast-like differentiation of these cells in vitro. To induce the odontoblast-like differentiation, we seeded hAECs over dentine disks treated with EDTA and evaluated the morphological characteristic of cells. We observed that hAECs present a characteristic odontoblast-like morphology, with cytoplasmic processes located in dentinal tubuli, after 48 h. Further studies will be carried out with known concentrations of dentine matrix proteins and qPCR.
El objetivo de esta tesis doctoral fue estudiar enfoques experimentales para la revitalización de dientes necróticos. La revitalización o endodoncia regenerativa es un tratamiento nuevo para dientes necróticos que busca regenerar el complejo dentino-pulpar, en lugar de obturar el conducto radicular con materiales biológicamente inertes (obturación radicular). Los dientes tratados endodónticamente permanecen desvitalizados durante toda la vida del paciente y, por lo tanto, indefensos ante nuevas lesiones de caries, ya que la ausencia de pulpa implica la falta del mecanismo inmune del diente. Por el contrario, la regeneración del complejo dentino-pulpar permite un mayor desarrollo de la raíz y tiene como objetivo recuperar el sistema inmune y secretor natural de la pulpa, haciendo que los dientes sean más resistentes a futuras lesiones o traumatismos. En esta tesis doctoral se realizó un estudio de elementos finitos que probó por primera vez que la distribución de la tensión mecánica es más desventajosa en dientes inmaduros y maduros con tejido reparativo (como el formado después de la endodoncia regenerativa), que en dientes desarrollados con dentina. Se llevaron a cabo estudios en material cadavérico para analizar métodos de ampliación del foramen apical de dientes maduros y un estudio experimental para evaluar a efectividad de la terapia en dientes maduros de hurón con forámenes ampliados. Los resultados mostraron que es posible la formación de un tejido conectivo vascularizado en el interior del canal de dientes maduros, pero este tejido ocupó solo el tercio apical. Se realizaron revisiones sistemáticas relativas al efecto de concentrados de plaquetas en la terapia, y se concluyó que si bien los dientes tratados con concentrados de plaquetas mostraron mejores resultados clínicos, el tejido neoformado es tejido reparativo, es decir, carente de odontoblastos y dentina. Se llevó a cabo un estudio in vitro para aislar y cultivar odontoblastos y se concluyó que no es posible mantener odontoblastos vitales in vitro, probablemente debido a la disrupción del proceso odontoblástico durante la aislación. Por último, se realizó experimentos in vitro que buscan evaluar la capacidad de diferenciación odontogénica de las células pluripotentes del amnios, investigación que actualmente está en fase de ejecución.

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Mohr, Benjamin J. "Durability of Pulp Fiber-Cement Composites." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7222.

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Wood pulp fibers are a unique reinforcing material as they are non-hazardous, renewable, and readily available at relatively low cost compared to other commercially available fibers. Today, pulp fiber-cement composites can be found in products such as extruded non-pressure pipes and non-structural building materials, mainly thin-sheet products. Although natural fibers have been used historically to reinforce various building materials, little scientific effort has been devoted to the examination of natural fibers to reinforce engineering materials until recently. The need for this type of fundamental research has been emphasized by widespread awareness of moisture-related failures of some engineered materials; these failures have led to the filing of national- and state-level class action lawsuits against several manufacturers. Thus, if pulp fiber-cement composites are to be used for exterior structural applications, the effects of cyclical wet/dry (rain/heat) exposure on performance must be known. Pulp fiber-cement composites have been tested in flexure to examine the progression of strength and toughness degradation. Based on scanning electron microscopy (SEM), environmental scanning electron microscopy (ESEM), energy dispersive spectroscopy (EDS), a three-part model describing the mechanisms of progressive degradation has been proposed: (1) initial fiber-cement/fiber interlayer debonding, (2) reprecipitation of crystalline and amorphous ettringite within the void space at the former fiber-cement interface, and (3) fiber embrittlement due to reprecipitation of calcium hydroxide filling the spaces within the fiber cell wall structure. Finally, as a means to mitigate kraft pulp fiber-cement composite degradation, the effects of partial portland cement replacement with various supplementary cementitious materials (SCMs) has been investigated for their effect on mitigating kraft pulp fiber-cement composite mechanical property degradation (i.e., strength and toughness losses) during wet/dry cycling. SCMs have been found to be effective in mitigating composite degradation through several processes, including a reduction in the calcium hydroxide content, stabilization of monosulfate by maintaining pore solution pH, and a decrease in ettringite reprecipitation accomplished by increased binding of aluminum in calcium aluminate phases and calcium in the calcium silicate hydrate (C-S-H) phase.

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27

Antonsson, Stefan. "Strategies for improving kraftliner pulp properties." Doctoral thesis, KTH, Träkemi och massateknologi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9718.

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A large part of the world paper manufacturing consists of production of corrugated board components, kraftliner and fluting, that are used in many different types of corrugated boxes. Because these boxes are stored and transported, they are often subjected to changes in relative humidity. These changes together with mechanical loads will increase the deformation of the boxes compared to the case where the same loads are applied in a static environment. This enlarged creep due to the changes in relative humidity is called mechano-sorptive or accelerated creep. Mechano-sorptive creep forces producers to use high safety factors when designing boxes, and therefore, this is one of the key properties of kraftliner boards. Different strategies to decrease mechano-sorptive creep, and to simultaneously gain more knowledge about the causes for this phenomenon in paper, are the aim of this work. Derivatised and underivatised black liquor lignins, a by-product produced in pulp mills in large quantities, have been used together with biomimetic methods, to modify the properties of kraftliner pulp. Furthermore, the properties of kraftliner pulp have been compared to other pulps in order to evaluate the influence of fibre morphological factors, such as fibre width and shape factor, on the mechano-sorptive creep. In addition the influence of the chemical composition of the kraftliner pulp has been evaluated both by means of treating a kraftliner pulp with chlorite and xylanase and by producing pulps with different chemical composition. By using lignin and biomimetic methods, to create radical coupling reactions, it has been shown that it is possible to increase the wet strength of kraftliner pulp sheets. This method of treating the pulp showed, however, no significant effects on the mechano-sorptive creep. The addition of an apolar suberin-like lignin derivative, which has been shown to be possible to produce from natural resources, did show a positive effect on mechano-sorptive creep properties, but at the expense of stiffness properties in constant climate. Different pulps were compared with a kraftliner pulp and it was observed that the ratio between tensile stiffness and hygroexpansion can be used to estimate the mechano-sorptive creep properties. The hardwood kraft pulps investigated had lower hygroexpansion, probably due to more slender and straighter fibres, and higher tensile stiffness, probably due to lower lignin content. As the lignin content was varied by different methods in kraft pulps, it was observed that increased lignin content gives an increased hygroexpansion and decreased tensile stiffness as well as an increased mechano-sorptive creep. There were also indications of increased mechano-sorptive creep due to higher xylan content.
En stor del av världens papperstillverkning utgörs av produktion av wellpappkomponenter, kraftliner och fluting, som används i en uppsjö av olika wellpapplådor. När dessa lådor lagras och transporteras utsätts de ofta för förändringar i relativa luftfuktigheten. Dessa förändringar tillsammans med mekanisk belastning ökar lådornas deformation jämfört med om samma belastning skulle ha applicerats vid ett statiskt klimat. Denna förhöjda krypning på grund av förändringarna i relativ luftfuktighet kallas mekanosorptiv- eller accelererad krypning. Mekanosorptiv krypning tvingar producenterna att ha höga säkerhetsmarginaler vid dimensioneringar av lådor och är därför en av nyckelegenskaperna för kraftliner. Olika strategier för att minska denna effekt, och på samma gång erövra mer kunskap om orsakerna till detta fenomen, har varit syftet med arbetet. Derivatiserade och oderivatiserade svartlutslignin, en biprodukt möjlig att få ut i stora kvantiteter från massabruk, har används tillsammans med biomimetriska metoder, för att modifiera kraftlinermassas egenskaper. Dessutom har kraftlinermassans egenskaper jämförts med andra massors egenskaper för att utvärdera inverkan av fibermorfologiska faktorer, såsom fiberbredd och fibreform på det mekanosorptiva krypet. Också inverkan av den kemiska sammansättningen av kraftliner massan har undersökts både genom behandling med klorit och xylanas och genom att producera massor med olika kemiska sammansättningar. Genom att använda lignin och biomimetriska metoder för att skapa radikal-kopplingsreaktioner har det visats på möjligheten att öka våtstyrkan i massa-ark. Det här sättet att behandla massa visade dessvärre inga signifikanta effekter på det mekanosorptiva krypet. Tillsatts av ett apolärt suberin-liknande ligninderivat, som visats möjligt att producera ur naturliga råmaterial, visade en positiv effekt på det mekanosorptiva krypegenskaperna även om det var på bekostnad av styvheten vid konstant klimat. Olika massor jämfördes med en kraftlinermassa och det observerades att relationen mellan dragstyvhet och hygroexpansion kan användas för att uppskatta de mekanosorptiva krypegenskaperna. Lövvedssulfatmassorna som undersöktes hade lägre hygroexpansion, antagligen beroende på smalare och rakare fibrer, och högre dragstyvhet, troligen beroende på en lägre ligninhalt. När ligninhalten varierades i sulfatmassor med olika metoder observerades att ökad ligninhalt ger en ökad hygroexpansion och minskad dragstyvhet liksom en ökad mekanosorptiv krypning. Dessutom fanns indikationer på en ökad mekanosorptiv krypning till följd av högre xylaninnehåll.
QC 20100629

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28

Stoor, T. (Tuomas). "Air in pulp and papermaking processes." Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:9514280784.

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Abstract A pulp suspension consists of water, fibres, fines, fillers and chemicals, but air or other gases are also present in practically all pulping processes either in dissolved form or as bubbles. Dissolved gases seldom disturb the processes, but they are readily converted to gaseous form when conditions change. The gas bubbles affect the properties of the pulp suspension, reduce the accuracy of certain measurements, interfere with the runability of the papermachine and detract from the quality of the end-product. Gases are removed from the process by either mechanical or chemical means, resulting in increased investments and operational costs. The aim of this work was to study the behaviour of gas in pulp and papermaking processes with laboratory, pilot-scale and mill-scale experiments. Five main areas of the research can be identified: 1. Occurrence of gases in pulp and paper mill processes, 2. Dissolution, precipitation and hold-up of gases in the pulp suspension and mill water, 3. Effects of gases on certain consistency measurements, centrifugal pumping and operation of the hydrocyclone. 4. Measurement of the gas content of the pulp suspension by compression, radiometric, microwave and sonar methods and 5. Removal of gases with a centrifugal pump equipped with vacuum pump or hydrocyclone equipped light reject removal. The results show that the dissolution and precipitation of gas is strongly dependent on the pulp and water properties. Dissolved and colloidal material reduces the solubility potential of gas, but also accelerates the precipitation of dissolved gases in gaseous form. The hold-up of precipitated gas bubbles was found to be much more pronounced in hydrophobic mechanical pulps than in lignin-free chemical pulps. The accuracy of consistency measurements was affected by free gas in the pulp suspension, requiring special attention when assessing the results. The operation of pressure screens and hydrocyclones was affected only at high volumes of free gas in the feed suspension. According to the experiments, a reliable gas content measurement can be achieved by in-line radiometric, microwave or sonar methods, and also by the off-line compression method if a representative sample is obtained. A centrifugal pump equipped with a gas removing unit is designed mainly to ensure undisturbed pumping, whereas its gas removal efficiency remains quite low, especially with small bubbles and at a low gas content. The gas removal efficiency of a hydrocyclone equipped with light reject removal is good, but decreases with small precipitated bubbles. These results offer new information of the behaviour of the gas in pulp suspensions and white water and underline the importance of the bubble generation mechanism in this context.

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29

Saarela, J. (Juha). "Photon migration in pulp and paper." Doctoral thesis, University of Oulu, 2004. http://urn.fi/urn:isbn:9514275845.

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Abstract The thesis clearly demonstrates that photon migration measurements allow characterization of pulp and paper properties, especially the fines and filler content of pulp, and the basis weight, thickness and porosity of paper. Pulp and paper are materials with a worldwide significance. Their properties strongly depend on the manufacturing process used. For efficient process control, the employed monitoring and measuring has to be fast. Therefore it is worthwhile to try to develop new approaches and techniques for such measurements. Recent advancements in optics offer new possibilities for such development. If two samples have different optical properties their photon migration distributions are different. The measurement of a photon migration distribution allows some features between two optically slightly dissimilar samples to be distinguished. Some simple measurements, which only yielded the photons' average time of flight, were made with an oscilloscope and a time-of-flight lidar. More precise measurements yielding photon pathway distribution or some selected characteristics like light pulse rise time, broadening, or fall time were measured with a streak camera. Two methods to assess photon path length distribution were introduced: particle determination with simulation, and streak camera with deconvolution. The basic properties for pulp are consistency and fines content and for paper the basic properties are thickness, basis weight and porosity. The influence on photon migration caused by changes in these basic properties was determined. As pulp and paper are rarely very basic, an additional property was demonstrated for both materials. For pulp it was the content of filler talc, and for paper it was the use of beaten pulp as a raw material. These additional properties were also distinguishable.

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30

Lin, Jack Cheng-Wei, and n/a. "Electric pulp testing of molar teeth." University of Otago. School of Dentistry, 2007. http://adt.otago.ac.nz./public/adt-NZDU20071221.140417.

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Testing the vitality of teeth using electric pulp testers was reviewed. Two studies then investigated aspects of the application of electric pulp testing (EPT) to healthy first molar teeth. Twenty volunteers with first molars free of restorations and caries were recruited. One molar from each arch was selected and rubber dam applied. The tester probe was coated with fluoride gel. Seven sites on each crown were EPT tested four times, and all threshold responses recorded. Data were analysed using one way ANOVA at the 0.01 level. The lowest response for both the maxillary and mandibular teeth was with the probe on the mesio-buccal cusp tip. Males responded at a lower level than females at the mesio-buccal cusp tip, but this did not reach statistical significance. The relationship between pulp areas and dimensions on radiographs and the EPT results was investigated. Standardised bitewing radiographs of the tested molars were mounted and digitally scanned. Five measurements were taken using a computer program; crown width, the mesial and distal pulp horn heights, the area of the clinical crown, and the pulp area in the clinical crown. The four electrode placement sites with the lowest threshold from the pulp testing results were selected. Pearson correlations (2-tailed) were used to relate the measurements. There were no correlations between the coronal pulp size, pulp horn height and the probe placement site. The exception was an anomalous correlation between the distal horn height and mesio-buccal cuspal area of the maxillary molars.

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31

Lawryshyn, Yuri Andrew. "Statics and dynamics of pulp fibres." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ27989.pdf.

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32

Mansfield, Shawn Denton. "Enzymatic modification of Douglas-fir pulp." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ27197.pdf.

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33

Yeoh, Sang Ju. "Electrospun cellulose fibres from kraft pulp." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/12930.

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Cellulose, the most abundant biomass extractable from wood, was generated in fibre form from kraft pulp by electrospinning, a fibre-producing process using electrostatic forces. Kraft pulping is the most dominant pulping technique in North America. Kraft pulp fibres (diam. 30μm) have a tensile strength of 700MPa and elastic modulus of 20GPa. In comparison, individual cellulose nanofibrils (diam. 5nm) have a tensile strength of 10GPa and elastic modulus of 150GPa. The strength displayed by cellulose nanofibrils suggests that the smaller fibre diameter could lead to a lower probability of including smaller flaw sizes in the fibre. Electrospinning has been successfully demonstrated as a one-step process to produce cellulose fibres directly from kraft pulp, thereby showing great potential for reducing cost and making the fibre-producing process more environmental friendly. Based on SEM and XRD, the electrospun fibres have a fibrillation-free, nano-filament structure with a seemingly cellulose I crystal structure, indicating significant potential for making crystalline cellulose fibres directly from kraft pulp. Contact angle measurements show that the electrospun fibres appear more hydrophobic than kraft pulp. The mechanical properties of the electrospun fibres have a large variation, suggesting the need for further process optimization. The ability to produce cellulose fibres directly from kraft pulp with improved moisture resistance and mechanical properties could potentially result in the development of more high value-added products for the Canadian pulp and paper industry, and perhaps even globally.

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34

Long, Xiaoping. "Minimum effluent process for pulp mill." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/11825.

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35

Marson, Andrew D. "Air flotation drying of paper pulp." Thesis, University of Manchester, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613430.

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Although much academic research has been devoted to the fields of paper drying and air impingement heat transfer, little of the resulting information is in a form usable to dryer manufacturers. The aim of this research was therefore to develop a model suitable for the designing the flotation dryers often used in the production of market pulps. The heat transfer characteristics of several commercial nozzle designs, namely flotation nozzles, slot nozzles and arrays of round orifices, were determined under conditions relevant to pulp drying. Empirical correlations for the Nusselt number for the nozzles were obtained using the property ratio method to account for the variation of the physical properties of air with temperature. The proposed correlations were shown to be in excellent agreement with the experimental results and were sufficiently accurate for use in industrial dryer design. The effect of the nozzle exit velocity and nozzle-to-surface spacing on the profile of static pressure at the impingement surface was also determined for a typical flotation nozzle design. The influence of nozzle conditions and sheet properties on the drying characteristics of papermaking pulp was determined through batch drying experiments. Over 400 experiments were performed using samples produced from four furnishes at basis weights in the range 120 g/m" to 2125 g/m2 and oven dry densities in the range 175 kg/mt to 900 kg/m'. Drying was achieved using heated air emerging from flotation nozzles at air temperatures in the range 100°C to 250°C with nozzle velocities between 15 mls and 55 mls. Temperature profiles through handsheets of both pressed and unpressed pulp were also measured during drying, which showed the presence of a quasi-constant temperature.

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36

Lima, Douglas Sáppia. "Pulp fiction: diálogos com outras mídias." Universidade Presbiteriana Mackenzie, 2015. http://tede.mackenzie.br/jspui/handle/tede/3047.

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This dissertation minds the formal aspects of the film Pulp Fiction (1994), by Quentin Tarantino, under a perspective of intermediality. Henceforth, it aims to assess the extent in which the director’s style fall back on signs and meaning settlements inherent to the language of other means of communication, such as the television, the comic books, video games and the past of the cinema itself. In these terms, the research divides itself into three main segments: the examination of the film narrative procedures (that concerns temporal ellipsis, flashbacks and a round structure intricate by three parallel stories); followed up by the discussion regarding the ostensive violence on the screen (which comprehends to the graphic violence stylization grounded on the saturation of visual signs and on the hybridization of different medias) and the analysis of dialogue constitution (which are granted within the Socratic dialogue and the post-modern conception of parody). In synthesis, in order to sustain the assumption that Pulp Fiction (1994) configures itself as a post-modern exponent, this research relies on the critical thoughts from authors who worked both with film and intermediality theories, as with language and post-modernity theories, such as Mauro Baptista Vedia (2010), Linda Hutcheon (1991) e Mikhail Bakhtin (1984).
Essa dissertação ocupa-se em estudar os aspectos formais do filme Pulp Fiction (1994), de Quentin Tarantino, sob uma perspectiva intermidiática. Para tanto, procura-se avaliar em que medida o estilo do diretor recorre a signos e procedimentos geradores de sentido inerentes à linguagem de outros meios de comunicação, como a televisão, as histórias em quadrinhos, os videogames e o próprio passado do cinema. Nesses termos, a pesquisa se divide, essencialmente, em três partes principais: o exame dos procedimentos narrativos do filme (que concernem a elipses temporais, flashbacks e uma estrutura circular intercalada por três histórias paralelas), seguido da discussão a respeito da violência ostensiva na tela (que compreende a estilização da violência gráfica com base na saturação de signos visuais e na hibridização de diversas mídias) e a análise da constituição dos diálogos (que estão pautados no diálogo socrático e na concepção pósmoderna da paródia). Em síntese, a fim de sustentar a pressuposição de que Pulp Fiction (1994) configura-se como um expoente do cinema pós-moderno, esse estudo se apoia no pensamento crítico de autores que trabalham tanto com teorias do cinema e da intermidialidade, quanto com teorias da linguagem e da pós-modernidade, como Mauro Baptista Vedia (2010), Linda Hutcheon (1991) e Mikhail Bakhtin (1984).

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37

Åkerlund, Agnes. "Time-Series Analysis of Pulp Prices." Thesis, Mittuniversitetet, Institutionen för informationssystem och –teknologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-39726.

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The pulp and paper industry has a significant role in Europe’s economy and society, and its significance is still growing. The pulp market and the customers’ requirements are highly affected by the pulp market prices and the requested kind of pulp, i.e., Elementary Chlorine Free (ECF) or Total Chlorine Free (TCF). There is a need to predict different market aspects, where the market price is one, to gain a better understanding of a business situation. Understanding market dynamics can support organizations to optimize their processes and production. Forecasting future pulp prices has not recently been done, but it would help businesses to make decisions that are more informed about where to sell their product. The studies existing about the pulp industry and forecast of market prices were completed over 20 years ago, and the market has changed since then in terms of, e.g., demand and production volume. There is a research gap within the pulp industry from a market price perspective. The pulp market is similar to, e.g., the energy industry in some aspects, and time-series analysis has been used to forecast electricity prices to support decision making by electricity producers and retailers. Autoregressive Integrated Moving Average (ARIMA) is one time-series analysis method that is used when data are collected with a constant frequency and when the average is not constant. Holt-Winters model is a well-known and simple time-series analysis. In this thesis, time-series analysis is used to predict the weekly market price for pulp the three upcoming months, with the research question “With what accuracy can time-series analysis be used to forecast the European PIX price on pulp on a week-ahead basis?”. The research method in this thesis is a case study where data are collected through the data collection method documents. First, articles are studied to gain understanding within the problem area leading to the use of the artefact time-series analyses and a case study. Then, historical data are collected from the organization FOEX Fastmarkets, where a new market price of pulp has been released every Tuesday since September 1996. The dataset has a total of 1200 data points. After data cleaning, it is merged to 1196 data points that are used for the analysis. To evaluate the results from the time-series analysis models ARIMA and Holt-Winter, Mean Absolute Error (MAE) and Mean Absolute Percentage Error (MAPE) are used. The software RStudio is used for programming. The results shows that the ARIMA model provides the most accurate results. The mean value for MAE is 16,59 for ARIMA and 44,61 for Holt-Winters. The mean value for MAPE is 1,99% for ARIMA and 5,37% for Holt-Winters.

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38

Morgan, David Ellis. "Pulp literature a re-evalutation [sic] /." Connect to this title online, 2002. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040820.122551.

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39

Tunc, Mehmet Sefik. "Relationship between Alkaline Pulp Yield and the Mass Fraction and Degree of Polymerization of Cellulose in Pulp." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/TuncMS2003.pdf.

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40

Monteiro, Viviana Ribeiro. "Desenvolvimento de polpas de fruta fermentadas." Master's thesis, ISA, 2013. http://hdl.handle.net/10400.5/6104.

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Mestrado em Engenharia Alimentar - Qualidade e Segurança Alimentar - Instituto Superior de Agronomia
The Food Industry is constantly on the lookout for innovation by developing new products with new flavors that are able to promote the well-being and the health of the consumers. The use of fermented fruit pulps is therefore one possible way to respond to this demand. The aim of this study was to develop low or non-alcoholic fermented beverages with low or no sugar content from pulps of pear, apple and peach. Four yeast strains and fourteen strains of lactic acid bacteria were tested, in mono and in co-culture. In the three fruit pulps, the combination of BC and LB in co-culture was the one that provided the best results. In apple and in pear pulps this combination was the most interesting in a sensory evaluation provided, while, in addition, the pulp of peach, besides good organoleptic properties reduced ºBrix to about 50% and reached approximately 2,5 % of ethanol (v/v).

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41

Abdel, Wahab. "An investigation into methods of dental pulp testing and factors affecting the response of the pulp to stimulation." Thesis, University of Edinburgh, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372981.

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42

Rezapour, Mehrnoosh. "Comparison of the effects of different pulp capping materials on viability, morphology and ageing of dental pulp cells." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/9236/.

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A significant amount of research has been directed towards the development of minimally invasive and/or regenerative therapeutic approaches to the maintenance of dental pulp vitality. Direct pulp capping is an example of such a therapeutic approach where the success of the treatment is largely affected by the biological characteristics of pulp capping agent. Tissue engineering approaches also include the use of human dental pulp cells (HDPCs) seeded on biocompatible scaffolds to regenerate lost hard, or soft dental tissues. Such processes may require a large number of cells which can only be produced by expansion of isolated HDPCs in vitro. Under these conditions, biological characteristics of the cells may be altered and their proliferation and differentiation capacity affected as a result of biological or cellular ageing. In this study we have investigated the effects of various pulp capping agents on HDPCs. Additionally we have looked at cell ageing and explored avenues to reduce the effects of this in vitro. HDPCs isolated from extracted human third molars were exposed to pulp capping agents through serial passage in culture. Dycal exhibited highly cytotoxic effects on the HDPCs, whereas, MTA facilitated the maintenance of cell viability and appeared to encourage proliferation of HDPCs. The use of propolis, a natural product of bees that has been reported to have uses in dentistry, resulted in slightly lower cell viability in comparison to the control and MTA groups. MTA and propolis appeared to enhance the osteogenic differentiation potential of HDPCs in comparison to control as indicated by the up-regulation of BMP-2, ALP, RUNX-2 and OCN and the undetectable expression of DSPP and DMP-1. We also clearly show that the biological characteristics of HDPCs (for example viability, cell proliferation and differentiation) were altered in later passages. A decrease in viability of cells treated with propolis seen in later passages, appeared to coincide III with the up-regulation of BCN1, a marker for for autophagy. Serially passaging of HDPCs also resulted in telomere shortening as measured by a progressive decrease of telomere restriction fragment (TRF) and this may lead to replicative senescence or cell ageing. Telomere shortening might be expected as expression of the telomerase associated gene (TERT) was undetectable. Contrary to expectations, propolis appeared to cause the greatest shortening of telomere length. Addition of the oligonucleotide “Telome 3”, which was designed to facilitate exogenous priming of telomeric DNA synthesis, to serially passaged HDPCs maintained high cell-viability throughout. Additionally, TRF measurements suggested that “Telome 3” may indeed aid in the maintenance of telomere length in serially passaged HDPCs. These data suggest that within the constraints of this in vitro model, the viability, proliferation and differentiation of HDPCs are largely affected by the cell passage number and also the type and concentration of the pulp capping agent used.

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43

Peterson, Aida N. "Antibacterial antibodies in the sera of patients needing endodontic therapy." Google Book Search Library Project, 1988. http://books.google.com/books?id=THg9AAAAMAAJ.

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44

He, Jie. "GASIFICATION-BASED BIOREFINERY FOR MECHANICAL PULP MILLS." Licentiate thesis, Mittuniversitetet, Institutionen för tillämpad naturvetenskap och design, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-17472.

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The modern concept of "biorefinery" is dominantly based on chemical pulp mills to create more value than cellulose pulp fibres, and energy from the dissolved lignins and hemicelluloses. This concept is characterized by the conversion of biomass into various biobased products. It includes thermochemical processes such as gasification and fast pyrolysis. In mechanical pulp mills, the feedstock available to the gasification-based biorefinery is significant, including logging residues, bark, fibre material rejects, biosludges and other available fuels such as peat, recycled wood, and paper products. This work is to study co-production of bio-automotive fuels, biopower, and steam via gasification in the context of the mechanical pulp industry. Biomass gasification with steam in a dual-fluidized bed gasifier (DFBG) was simulated with ASPEN Plus. From the model, the yield and composition of the syngas and the contents of tar and char can be calculated. The model has been evaluated against the experimental results measured on a 150 KWth Mid Sweden University (MIUN) DFBG. The model predicts that the content of char transferred from the gasifier to the combustor decreases from 22.5 wt.% of the dry and ash-free biomass at gasification temperature 750 ℃ to 11.5 wt.% at 950 ℃, but is insensitive to the mass ratio of steam to biomass (S/B). The H2 concentration is higher than that of CO under normal DFBG operating conditions, but they will change positions when the gasification temperature is too high above about 950 ℃, or the S/B ratio is too far below about 0.15. The biomass moisture content is a key parameter for a DFBG to be operated and maintained at a high gasification temperature. The model suggests that it is difficult to keep the gasification temperature above 850 ℃ when the biomass moisture content is higher than 15.0 wt.%. Thus, a certain amount of biomass needs to be added in the combustor to provide sufficient heat for biomass devolatilization and steam reforming. Tar content in the syngas can also be predicted from the model, which shows a decreasing trend of the tar with the gasification temperature and the S/B ratio. The tar content in the syngas decreases significantly with gasification residence time which is a key parameter. Mechanical pulping processes, as Thermomechanical pulp (TMP), Groundwood (SGW and PGW), and Chemithermomechanical pulp (CTMP) processes have very high wood-to-pulp yields. Producing pulp products by means of these processes is a prerequisite for the production of printing paper and paperboard products due especially to their important functional properties such as printability and stiffness. However, mechanical pulping processes consume a great amount of electricity, which may account for up to 40% of the total pulp production cost. In mechanical pulping mills, wood (biomass) residues are commonly utilized for electricity production through an associated combined heat and power (CHP) plant. This techno-economic evaluation deals with the possibility of utilizing a biomass integrated gasification combined cycle (BIGCC) plant in place of the CHP plant. Integration of a BIGCC plant into a mechanical pulp production line might greatly improve the overall energy efficiency and cost-effectiveness, especially when the flow of biomass (such as branches and tree tops) from the forest is increased. When the fibre material that negatively affects pulp properties is utilized as a bioenergy resource, the overall efficiency of the system is further improved. A TMP+BIGCC mathematic model is developed based on ASPEN Plus. By means of this model, three cases are studied: 1) adding more forest biomass logging residues in the gasifier, 2) adding a reject fraction of low quality pulp fibers to the gasifier, and 3) decreasing the TMP-specific electricity consumption (SEC) by up to 50%. For the TMP+BIGCC mill, the energy supply and consumption are analyzed in comparison with a TMP+CHP mill. The production profit and the internal rate of return (IRR) are calculated. The results quantify the economic benefit from the TMP+BIGCC mill. Bio-ethanol has received considerable attention as a basic chemical and fuel additive. It is currently produced from sugar/starch materials, but can also be produced from lignocellulosic biomass via a hydrolysis--fermentation or thermo-chemical route. In terms of the thermo-chemical route, a few pilot plants ranging from 0.3 to 67 MW have been built and operated for alcohols synthesis. However, commercial success has not been achieved. In order to realize cost-competitive commercial ethanol production from lignocellulosic biomass through a thermo-chemical pathway, a techno-economic analysis needs to be done. In this work, a thermo-chemical process is designed, simulated, and optimized mainly with ASPEN Plus. The techno-economic assessment is made in terms of ethanol yield, synthesis selectivity, carbon and CO conversion efficiencies, and ethanol production cost. Calculated results show that major contributions to the production cost are from biomass feedstock and syngas cleaning. A biomass-to-ethanol plant should be built at around 200 MW. Cost-competitive ethanol production can be realized with efficient equipments, optimized operation, cost-effective syngas cleaning technology, inexpensive raw material with low pretreatment cost, high-performance catalysts, off-gas and methanol recycling, optimal systematic configuration and heat integration, and a high-value byproduct.

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45

Sillanpää, M. (Mervi). "Studies on washing in kraft pulp bleaching." Doctoral thesis, Oulun yliopisto, 2005. http://urn.fi/urn:isbn:9514278771.

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Abstract Washing during kraft pulping can be divided into two separate areas each with its own distinct features: namely brownstock washing and washing in bleaching. Research interest has so far concentrated mostly on investigating brownstock washing and factors affecting its efficiency. Pulp washing in bleaching, however, has been practically neglected. The basic phenomena are the same as in brownstock washing, but there are differences which have not been taken into consideration to a sufficient extent. This less explored area is the focus of this research. In this thesis, it is shown that brownstock washing and pulp washing between bleaching stages are distinct areas with their own specific features. They differ for example in terms of the composition and molecular size of the impurities in the pulp suspension. Various process conditions, pH, temperature and so on cause further differences between washing in bleaching and brownstock washing. The removal of specific compounds can be clearly affected by the appropriate selection of wash liquor. It is shown that the dynamic behaviour during washing is different for different compounds and depends on the properties of the wash water. The key element is to find the most harmful compounds in specific positions in bleaching and on the basis of that finding, to determine the most suitable wash liquor system. Chemical oxygen demand (COD) is a widely used method for evaluating the washing result, but as a collective measurement variable it does not describe the actual compounds that cause the "loss" of bleaching chemicals. Studies have shown that many compounds contribute to COD load but ultimately most of them have no real effect on the bleaching result. A suggestion for more precise definition of wash loss is offered than COD.

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46

Farr, Gary Derek. "Chlorination effluent recycle in kraft pulp bleaching." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/29938.

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When performed at an industrial scale, kraft pulp bleaching commonly utilizes recycled chlorination effluent for brown stock dilution. Much of the information regarding this practice pertains to pulp quality. Some of the previous research done in this field failed to separate its effect from the effect of countercurrent effluent recycle for pulp washing. In addition, there are some shortcomings of the batch techniques that have been used to simulate effluent recycle in the laboratory. Thus little is known about the effect of this practice on effluent quality. Accordingly, the objective of this research project was to determine the effect of chlorination effluent recycle for brown stock dilution on the quality of kraft pulp bleaching effluent. Chlorination effluent recycle was investigated in conjunction with the variables of multiple, mode, and chlorine dioxide substitution. Effluent quality was characterized in terms of toxicity, total chlorinated organic compounds, and chlorate. Pulp quality was also measured. A full 2⁴ factorial design was carried out with 24 bleaching runs. The experimentation was performed in the laboratory using a two-stage (CE) bleaching sequence. A specially designed continuous laboratory-scale pulp chlorination apparatus, which was operated with an unbleached pulp throughput of 6 odg/min, was used to execute the first stage. By producing sufficient quantities of effluent at steady state in a short period of time, this apparatus enabled the efficacious use of trout bioassays. The second stage was performed on a batch basis. Results from the laboratory experiments were compared to those from an industrial-scale bleach plant. The chlorination stage toxic emission factor for rainbow trout decreased by 314 m³/adt as the level of recycle was increased from 4.5 to 22.5 m³/adt. The effects of multiple, mode, and substitution were also significant. Effluents from the extraction stage were much less toxic than those from the chlorination stage. The first stage toxic emission factors for trout and luminescent marine bacteria were not correlated. In addition, the concentration of organochlorine compounds and the number of toxic units were not correlated. A novel method for determining the toxic emission factor from median lethal time data was also developed. Recycle had no significant effect on the total production of chlorinated organic compounds, which were quantified together in terms of AOX. A regression equation, which includes the effects of multiple and mode as well as the interaction between multiple and substitution, was formulated for the AOX results. Recycle had no significant effect on the production of chlorate. A regression equation, which includes the variables of substitution and mode, was formulated for the chlorate results. A hypothesis, which involves the reactions of chlorine and chlorine dioxide with the phenolic hydroxyl groups of lignin, was developed to explain several characteristics of this equation. Recycle also had no effect on pulp quality, which was measured after the extraction stage with the kappa number and the viscosity. Mode and multiple were the only factors that significantly affected the kappa number. A hypothesis, which involves the reactions of chlorine and chlorine dioxide with dissolved organic material in the chlorination stage, was developed to explain the effect of mode on delignification. None of the variables had a significant effect on the viscosity.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate

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47

Koren, David W. "Column hydrodynamics of solvent in pulp processing." Thesis, University of Ottawa (Canada), 1987. http://hdl.handle.net/10393/5463.

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48

Ajersch, Michael John. "Mechanisms of pulp loss in flotation deinking." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ30126.pdf.

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49

Yuan, Zhirun. "Peracetic acid brightening of softwood kraft pulp." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ29474.pdf.

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Melanson, Jason B. "Effluent recycling in a Kraft pulp mill." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0009/MQ60153.pdf.

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Dissertations / Theses on the topic 'Pulp'

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