947 resultados para pulp samples
Resumo:
Tämän tutkimuksen tarkoituksena on tutkia sellu- ja paperiteollisuuden toimintojen luonnetta sekä miten yrityksen rajapinnat ovat muodostuneet ko. teollisuudenalalla. Tutkimus on eksploratiivinen ja luonteeltaan kvalitatiivinen. Tutkimuksen aineisto kerättiin yrityksissä tehdyillä teemahaastatteluilla. Sellu- ja paperitehtaan toimintojen analysoinnissa käytetään resurssiperusteista näkemystä ja transaktiokustannusteoriaa. Tutkimuksen yritysten rakennetta voidaan pitää varsin konservatiivisena. Teoreettinen kehys pystyi selittämään varsinaisen tuotannon järjestämistä varsin hyvin. Tukitoiminnoissa löytyi ristiriitoja teorian ja todellisuuden välillä. Tuotantotoiminnot kannattaa pitää yrityksen sisällä, koska ne täyttävät VRIN-attribuutit ja niihin liittyy korkeita transaktiokustannuksia. Suurin osa tukitoiminnoista voidaan luokitella triviaaleiksi. Joitain tukitoimintoja voidaan kuitenkin luokitella strategisesti tärkeiksi, ja voidaan päätellä, että ne pitäisi pitää yrityksen sisällä. Tässä suhteessa tulokset olivat kuitenkin ristiriitaisia, ja lisätutkimuksia tarvittaisiin lopullisten johtopäätösten tekemiseen.
Resumo:
Tutkielman tavoitteena oli analysoida erilaisia strategisia orientaatioita sellu- ja paperiteollisuudessa. Sellu- ja paperiteollisuus on kohtaamassa strategisia haasteita, jotka ulottuvat syvälle sen rakenteisiin. Yritykset ovat valinneet erilaisia lähestymistapoja organisoidessaan tuotantoa ja kansainvälistä arvoketjuaan tässä muuttuvassa ympäristössä. Tutkimukseen valittiin 30 suurinta sellu- ja paperiteollisuudessa toimivaa yritystä ja mahdollisia syitä kannattavuuseroihin yritysten välillä analysoitiin. Yritysten strategista orientaatiota tarkasteltiin vertailemalla muun muassa seuraavia tekijöitä: vertikaalinen integraatioaste, tuotevalikoiman laajuus, tuotantokapasiteetin levinneisyys ja tuotantokapasiteetin ikä. Kannattavuutta mitattiin erilaisilla talouden tunnusluvuilla (liikevoitto, oman pääoman tuotto-%, koko pääoman tuotto-%). Tulosten mukaan yrityksiä voidaan ryhmitellä strategisen orientaation perusteella ja ryhmien välillä on kannattavuuseroja.
Resumo:
Tutkimuksen tavoitteena on analysoida 74 sellu- ja paperiyrityksen taloudellista suorituskykyä kannattavuutta, maksuvalmiutta, vakavaraisuutta ja arvonluontikykyä kuvaavilla tunnusluvuilla. Tutkimuksen teoriaosa esittelee liiketoiminta-analyysin välineet, jonka jälkeen esitellään taloudelliset tunnusluvut. Empiriaosassa käydään läpi vuoden 2005 tunnusluvut yritystasolla. Jotta voidaan tarkastella tunnuslukujen muutoksia pitkällä aikavälillä, yritykset ryhmitellään maantieteellisen sijainnin sekä liiketoimintaorientaation mukaan. Tutkimus on kuvaileva. Tunnusluvuista voidaan todeta sellu- ja paperiteollisuudessa meneillään oleva toimialan rakennemuutos. Eteläamerikkalaiset yritykset, jotka hyötyvät uudesta ja kustannustehokkaasta raaka-aineesta, ovat siirtyneet lähemmäs arvonluontia, kun taas suurin osa pohjoisamerikkalaisista yrityksistä, jotka olivat toimialan johtavia arvonluojia, ovat nyt arvon tuhoajia. Toimiala kärsii myös alhaisesta kannattavuudesta, joka vaikuttaa eniten pohjoisamerikkalaisiin yrityksiin. Samaan aikaan eteläamerikkalaiset yritykset ovat nostaneet kannattavuuttaan, mikä puolestaan korostaa meneillään olevaa muutosta.
Resumo:
Fiber damages comprise fiber deformations, characterized as fiber curl, kink, dislocations and strength losses as well as some yet unidentified factors. This recently discovered phenomenon is especially evident in mill scale kraftpulps. Laboratory produced pulps tend to have less damages and superior strength properties compared to those produced in pulp mills. Generally fiber damages pose a problem in the production of reinforcement pulp because they tend to decrease the ability of fibers to transmit load. Previous studies on fiber damage have shown that most of the fiber damages occur during brown stock processing starting from cooking and discharging. This literature review gives an overall picture on fiber damages occurring during softwood kraft pulp production with an emphasis on the oxygen delignification stage. In addition the oxygen delignification stage itself is described in more detailed extent in order to understand the mechanisms behind the delignification and fiber damaging effect. The literature available on this subject is unfortunately quite contradictory and implicates a lotof different terms. Only a few studies have been published which help to understand the nature of fiber damages. For that reason the knowledge presented in this work is not only based on previous studies but also on research scientist and mill staff interviews.
Resumo:
Process development will be largely driven by the main equipment suppliers. The reason for this development is their ambition to supply complete plants or process systems instead of single pieces of equipment. The pulp and paper companies' interest lies in product development, as their main goal is to create winning brands and effective brand management. Design engineering companies will find their niche in detail engineering based on approved process solutions. Their development work will focus on increasing the efficiency of engineering work. Process design is a content-producing profession, which requires certain special characteristics: creativity, carefulness, the ability to work as a member of a design team according to time schedules and fluency in oral as well as written presentation. In the future, process engineers will increasingly need knowledge of chemistry as well as information and automation technology. Process engineering tools are developing rapidly. At the moment, these tools are good enough for static sizing and balancing, but dynamic simulation tools are not yet good enough for the complicated chemical reactions of pulp and paper chemistry. Dynamic simulation and virtual mill models are used as tools for training the operators. Computational fluid dynamics will certainlygain ground in process design.
Resumo:
The aim of this thesis was to produce information for the estimation of the flow balance of wood resin in mechanical pulping and to demonstrate the possibilities for improving the efficiency of deresination in practice. It was observed that chemical changes in wood resin take place only during peroxide bleaching, a significant amount of water dispersed wood resin is retained in the pulp mat during dewatering and the amount of wood resin in the solid phase of the process filtrates is very small. On the basis of this information there exist three parameters related to behaviour of wood resin that determine the flow balance in the process: 1. The liberation of wood resin to the pulp water phase 2. Theretention of water dispersed wood resin in dewatering 3. The proportion of wood resin degraded in the peroxide bleaching The effect of different factors on these parameters was evaluated with the help of laboratory studies and a literature survey. Also, information related to the values of these parameters in existing processes was obtained in mill measurements. With the help of this information, it was possible to evaluate the deresination efficiency and the effect of different factors on this efficiency in a pulping plant that produced low-freeness mechanical pulp. This evaluation showed that the wood resin content of mechanical pulp can be significantly decreased if there exists, in the process, a peroxide bleaching and subsequent washing stage. In the case of an optimal process configuration, as high as a 85 percent deresination efficiency seems to be possible with a water usage level of 8 m3/o.d.t.
Resumo:
Este estudio ex post facto analiza las relaciones entre las dimensiones y facetas del NEO-PI-R y los 14 trastornos de personalidad del MCMI-III en una muestra no clínica española (N = 674). Se exploran las diferencias y similitudes con los resul- tados de Dyce y O’Connor en una muestra americana con los mismos instrumentos. Como se esperaba, los análisis factoriales de facetas reteniendo cinco factores mostraron un modelo de relaciones muy similar entre ambas muestras, con un coeficiente de la congruencia total de 0,92, y coeficientes de congruencia de factor aceptables, salvo para el factor Apertura (0,68). En consonancia con las predicciones de Widiger y Widiger et al. los porcentajes de correlaciones significativas estaban alrededor de 60% en ambas muestras, y la mayoría coincidían. El análisis de regresión múltiple con dimensiones también reveló un gran parecido entre los resultados americanos y españoles, Neuroticismo fue el predictor más relacionado con los trastornos de personalidad. Se encontraron diferencias en las regresiones por facetas, aunque la varianza explicada fue prácticamente la misma que en las dimensiones. Se discute la validez transcultural y el valor predictivo del NEO-PI-R sobre los trastornos de personalidad del MCMI-III, junto con las ventajas relativas de las facetas sobre las dimensiones.
Resumo:
Near-infrared spectroscopy (NIRS) was used to analyse the crude protein content of dried and milled samples of wheat and to discriminate samples according to their stage of growth. A calibration set of 72 samples from three growth stages of wheat (tillering, heading and harvest) and a validation set of 28 samples was collected for this purpose. Principal components analysis (PCA) of the calibration set discriminated groups of samples according to the growth stage of the wheat. Based on these differences, a classification procedure (SIMCA) showed a very accurate classification of the validation set samples : all of them were successfully classified in each group using this procedure when both the residual and the leverage were used in the classification criteria. Looking only at the residuals all the samples were also correctly classified except one of tillering stage that was assigned to both tillering and heading stages. Finally, the determination of the crude protein content of these samples was considered in two ways: building up a global model for all the growth stages, and building up local models for each stage, separately. The best prediction results for crude protein were obtained using a global model for samples in the two first growth stages (tillering and heading), and using a local model for the harvest stage samples.
Resumo:
The work had as objective the physico-chemical characterization of yellow mangosteen fruits. Six samples of 25 fruits were harvested in yellow mangosteen plants of the Active Germoplasm Bank of São Paulo State University and characterized by evaluation of length and width, weight, percentage and number of seeds per fruit, peel and pulp percentage, soluble solid (SS), titratable acidity (TA), vitamin C and SS/TA rate. Yellow mangosteen fruit is an intermediate vitamin C source with an average content 120.33 mg/100g of fresh fruit and has good technological quality.
Resumo:
Background: Coxiella burnetii is a highly clonal microorganism which is difficult to culture, requiring BSL3 conditions for its propagation. This leads to a scarce availability of isolates worldwide. On the other hand, published methods of characterization have delineated up to 8 different genomic groups and 36 genotypes. However, all these methodologies, with the exception of one that exhibited limited discriminatory power (3 genotypes), rely on performing between 10 and 20 PCR amplifications or sequencing long fragments of DNA, which make their direct application to clinical samples impracticable and leads to a scarce accessibility of data on the circulation of C. burnetii genotypes. Results: To assess the variability of this organism in Spain, we have developed a novel method that consists of a multiplex (8 targets) PCR and hybridization with specific probes that reproduce the previous classification of this organism into 8 genomic groups, and up to 16 genotypes. It allows for a direct haracterization from clinical and environmental samples in a single run, which will help in the study of the different genotypes circulating in wild and domestic cycles as well as from sporadic human cases and outbreaks. The method has been validated with reference isolates. A high variability of C. burnetii has been found in Spain among 90 samples tested, detecting 10 different genotypes, being those adaA negative associated with acute Q fever cases presenting as fever of intermediate duration with liver involvement and with chronic cases. Genotypes infecting humans are also found in sheep, goats, rats, wild boar and ticks, and the only genotype found in cattle has never been found among our clinical samples. Conclusions: This newly developed methodology has permitted to demonstrate that C. burnetii is highly variable in Spain. With the data presented here, cattle seem not to participate in the transmission of C. burnetii to humans in the samples studied, while sheep, goats, wild boar, rats and ticks share genotypes with the human population.
Resumo:
In order to determine the penetration of the thermal wave in the papaya fruit pulp (Carica papaya L.), cv. Golden, thermal diffusivity of the pulp was obtained measuring temperature at four different depths. Measurements were carried out initially with the fruit on the first stage of maturity. The changes of the thermal diffusivity were expressed as a function of ripening. A temporal decrease of the thermal diffusivity was observed. Chemical (pH, soluble solids and total titratable acidity) and physical (pulp firmness) properties were measured as well and the results were compared to the thermal diffusivity change.
Resumo:
Anaerobic treatment as a first biological stage in wastewater treatment is nowadays a well-established technology in recycled paper processing mills using closed water circuits. Today further developed high-rate processes and especially high-tower reactors are also able to handle lower organic loads and become therefore feasible for deinking pulp plant effluents. The interest in the anaerobic method is based on a positive energy balance in form of biogas production and low biomass yield from the process. The anaerobic treatment method was researched and its suitability for the deinking pulp plant effluents was tested experimentally at Stora Enso Maxau mill. In the theory, the deinking pulp process is introduced and the effluents from the deinking process are characterized. The anaerobic treatment is brought up in depth in terms of its use for the deinking effluents, and different kind of reactor types are presented. In addition, other wastewater treatment methods are shortly introduced with the focus on tertiary treatment. Static biodegradability tests were carried out for the wastewaters both anaerobically and aerobically. Based on the results, the deinking effluents can be degraded anaerobically, and inhibition to the methanogenic bacteria was not noticed. In the aerobic static test a good performance of the existing wastewater treatment plant at Maxau mill was proved. Later on pilot trials with sequential anaerobic-aerobic treatment were carried out for the deinking effluents. The anaerobic reactor used was a so called internal circulation reactor. The results confirmed that the combination of the anaerobic treatment and the aerobic activated sludge process is a suitable method for deinking wastewaters with a COD reduction as good as with a two stage aerobic method. When combined with the outstanding quality of the produced biogas and the cost savings acquired from the lower sludge production, the anaerobic treatment was found to be an especially favorable treatment method.
Resumo:
Mauritia vinifera (buriti) is a palm tree that grows wild in different areas of Brazil, particularly in the Amazonian region. The buriti oil is rich in carotenoids, especially in β-carotene. The growing interest in other natural sources of β-carotene has stimulated the industrial use of buriti as a raw material for pulp oil extraction. Most processes are based on the conventional technologies, involving drying and pressing the pulp for oil recovery and further separation of carotenoids in a liquid phase using organics solvents. In the present work, the ethanol-based process was evaluated for simultaneous carotenoids recovering and fractionating from buriti pulp. The raw material and ethanol, 1:4 ratio, were placed in an erlenmeyer flask and maintained at 30rpm for 1 hour in a temperature-controlled bath at 65ºC. The mixture was filtered under vacuum and cooling at 10ºC to allow for the separation of the solvent in two phases. Carotenoids composition, determined by HPLC, has indicated a β-carotene concentration about 12 times greater in the lower phase than in the upper phase. The profile of the carotenoids in the denser phase is quite similar to that of raw buriti oil, and the concentration of total carotenoids is 40% higher than that of the original raw oil, making the ethanol-based process particularly attractive for industrial applications.
Resumo:
Gelled aspect in papaya fruit is typically confused with premature ripening. This research reports the characterization of this physiological disorder in the pulp of papaya fruit by measuring electrolyte leakage, Pi content, lipid peroxidation, pulp firmness, mineral contents (Ca, Mg and K - in pulp and seed tissues), and histological analysis of pulp tissue. The results showed that the gelled aspect of the papaya fruit pulp is not associated with tissue premature ripening. Data indicate a reduction of the vacuole water intake as the principal cause of the loss of cellular turgor; while the waterlogged aspect of the tissue may be due to water accumulation in the apoplast.