Isolation of birch xylan as a part of pulping-based biorefinery

This study combines various aspects of xylan isolation from birch wood as part of a pulping-based biorefinery concept. Acidic prehydrolysis and alkaline pre-extraction are the two processes used as the starting point of the work. Solutions of xylan with diverse macromolecular and chemical properties were obtained by applying different pre-treatments. Pre-extraction at high alkalinity produced water-insoluble xylan with a high molar mass and low polydispersity. Autohydrolysis at a mild intensity yielded a liquid phase containing a variety of xylooligosaccharides and xylan of low molar mass. The fragments were mainly acetylated and some of them carried 4-O-methylglucuronic acid substituents. Intensification of autohydrolysis promoted formation of monomeric xylose and its degradation products. The addition of oxalic acid increased the monomeric fraction even at mild prehydrolysis intensities. The properties of cellulose in the wood residue were affected to a smaller or greater extent depending on the type and intensity of the pre-treatment. After alkaline pre-extraction at low temperature and high alkalinity, the macromolecular properties of cellulose were barely affected. After mild prehydrolysis, cellulose was partly depolymerised without a notable yield loss. When more severe prehydrolysis conditions were applied, as required for an almost complete removal of hemicelluloses, both the degree of polymerisation and yield of cellulose were affected dramatically. An attempt to mitigate gradual cellulose degradation induced in the pulping stage by prehydrolysis was made with cotton linters as a cellulose substrate. Sodium borohydride and different types of anthraquinone (AQ) were able to convert a share of the reducing end groups to either alditol or aldonic acid moieties stable to alkaline peeling. Such stabilisation had a positive effect on the yield of cellulose. Stabilisation was also reflected in the decreased ratios between the peeling and stopping reaction rate constants. An improved model for cellulose degradation in alkaline environments was developed that took secondary peeling into account. Application of the stabilisation chemicals to birch wood resulted in a moderate yield increase and the preferred stabilisation of hemicelluloses. Aqueous-phase prehydrolysis of birch wood followed by alkaline pulping produced dissolving pulps of viscose and acetate quality without alkaline post-extraction. Changes of cellulose crystallite dimensions and specific surface area between microfibril aggregates in bleached pulps were observed as functions of prehydrolysis intensity. Mild oxalic acid prehydrolysis and alkaline pre-extraction were shown to be well suited the production of paper pulps, where the latter pre-treatment ensured excellent papermaking properties

Intangible assets and competitiveness in Spain: an approach based on trademark registration data in Catalonia (1850-1946)

This paper studies the origins of trademark registration in Spain and offers, for the first time, data across sectors and regions with a long-term perspective. In apparent contradiction to the slow path of industrialization and the economic backwardness of Spain between 1850 and the 1940s, empirical evidence on trademark registration suggests that, in this field, Spanish policies and Spanish firms seemed to be well ahead of other countries. Spain was among the pioneering countries in the Western world in having a state legislation protecting brand registration since 1850. Also, some Spanish regions and industrialized sectors adopted similar strategies to those of its European counterparts in terms of using consistently branding and registered trademarks. Our evidence suggests that firms seem to have used brands and marks, first to fight against fraud and imitation and second to add intangible assets to its products in order to endow them with persistent identity trends regarding origins or quality of the product that were difficult to replicate, as often happened with patents. This created and accumulated, over that period of time, a marketing knowledge among consumers, which may have been useful to maintain the competitiveness of some industrial districts and regions.Intangible assets; Trade Marks; Brands; Catalonia, Spain.

A hybrid algorithm for the integrated production planning in the pulp and paper industry

Tese de mestrado integrado. Engenharia Industrial e Gestão. Faculdade de Engenharia. Universidade do Porto. 201

Simulation and optimisation of the controls of the stock preparation area of a paper machine.

Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2004.At Mondi Paper Ltd, Merebank, South of Durban, Paper Machine 2 has recently been transferred onto a Distributed Control System (DCS). This was seen as a good opportunity to enhance the control of the pulp feed to the machine. A prime concern in operating a paper machine is to ensure consistent set-point paper properties in the Cross-Direction (CD: ie. across the paper width) and in the Machine-Direction (MD: ie. along the paper length). Sophisticated adjustments are available to ensure an even feed of the stock (consistencies around 2% m/m wood fibres in water) from the head-box across the receiving width of the paper machine. The properties of prime interest as the pulp is pumped through the head-box distributor onto the receiving belt of the machine are the basis weight (fibre mass per unit area) and moisture content (per unit area). However, the distribution system is highly dependent on the properties of the stock as it arrives at the head-box. Variations in upstream chest levels, the supplied pressure, flow-rate and fibre/water ratio, all cause MD and even CD variations. The problems of maintaining steady conditions at the head-box are well known, and are understood to arise from sub-optimal control in the preceding section involving a blend chest and machine chest, amongst other items, where several pulp streams and dilution water are combined. A number of control loops are involved, but appear to require different tuning for different paper grades. Often individual loops are taken off-line. In this study, an understanding of the controller interactions in the stock preparation section has been developed by detailed dynamic modelling, including all of the existing control loops. The model is built up in a modular fashion using a basic element, having one input (which can collect multiple streams originating elsewhere) and four outputs, linked through a vessel of variable volume. Several basic elements are linked together to form the overall system. All of the necessary properties can be defined so that the model allows the simulation of all features of the network: vessels, pipes, junctions, valves, levels and consistencies. A set of first order differential equations is solved which includes total water balance, species mass balances, derivatives of flow controller action, and derivatives of supervisory controller action. Supervisory controllers for consistency or level cascade onto flow controllers. Flow controllers manipulate valves which give a first-order dynamic response of actual flow. Where valves are manipulated directly by the supervisory level, the flow controller is effectively bypassed. This study involves a constraint problem around the blend chest, resulting in a loss of specification at the paper machine. This was solved by the implementation of a static optimiser. Its objective function penalizes deviations from setpoint of five parameters (ratios, consistency and level) using respective weight factors. Both the model and its optimiser were included in a simulator designed with the graphical user interface (GUI) of Matlab. The simulator has then been used to explore control performance over the operating range, by means of a set of scenarios

Making Cycling Spaces in Hilly Cities

Traffic congestion and environmental pollution in cities have stimulated the rise of policies to encourage practices of less polluting, and more economic and healthier modes of transportation, such as cycling. Several factors influence bicycle use, including the steep gradients which can limit it use, but do not completely prevent it. In this context, urban planning and transport engineering play a key role in promoting cycling, with particular emphasis on the definition and design of cycling networks at hilly cities, according to the citizens’ needs on their daily commutes. To address this challenge, this paper describes the starting developments and the methodological approach of a doctoral research having the following goals: to define the data to be considered in feasibility studies of designing cycling mode in hilly cities; to develop a bicycle suitability model based on demographic, travel-generating poles, type of bicycles (regular vs. electric) and road network criteria; to develop a model to support the definition of cycling network based on connectivity, network intersections, integration with other modes of transportation, parking and safety; and to define a procedure for assessing solutions and define cycling routes hierarchy, having as case study the hilly city of Covilhã, at Serra da Estrela mountain

Estimation of Wood Pulp Fiber Species Composition From Microscopy Images Using Computer Vision

Pulp mills and papermakers require careful control of input raw materials. The paper pulp composition, consisting of blends of different wood fiber types, affects multiple final product properties in interacting ways and impacts process operating conditions. Manual estimation of composition by classification and counting using microscopy is time consuming, repetitive, error-prone, and fibers are not always identifiable. Using a dataset of 359,840 fibers from 12,690 images of either hardwood or softwood fibers from 423 microscopy slides with data partitioned into 60% training, 20% validation, and 20% testing splits by slide, and a sequence of principal components analysis, Gaussian mixture, image analysis, and convolutional neural network models this work demonstrates a system capable of processing 4.92 megapixel microscopy images with 3 color channels at a rate of 30 seconds per image using a 4gb Nvidia Jetson Nano computer with a fiber-segment level test accuracy of 91%. The variation in accuracy between slides is statistically significant and follows a beta-binomial distribution, which controls the required number of slides for confident estimation of actual process mixture composition; the described implementation requires 10 slides for a 90% interval of ±3.25% of the estimated composition. Additionally, anomalous cotton fibers, not present in training data, are correctly identified with a rate of 33% false negatives and 5% false positives. The entire process is visualized, enhancing interpretability, and understanding of fundamental fiber structures. The complete system enables papermakers and pulp mills to improve control of the input concentrations of component fibers and appropriately adjust corresponding operating conditions to achieve desired properties. Studying the classification results, we the identify the influence of confounding factors in our data; changing confounding factors from one slide to the next influences not only the species of fiber, but also the observation conditions, such as illumination, imaging, and slide preparation. Then, by simulating a dataset of microscopy slides, in which the influence of such confounders is not present, we demonstrate that it is not the simplicity of the objects of interest that limits the use of high capacity models for learning, but hypothesize the presence of an easily learnable feature that varies from slide to slide and is detectable among many objects from the same slide. Mitigating this feature could greatly improve learning of otherwise relevant but subtle fiber features

Chemical Characterisation And The Effect Of Alkaline Pulping Of Malaysia Cultivated Kenaf (Hibiscus Cannabinus)

A comprehensive study is carried out on the chemical composition of the bast and core of the Hibiscus cannabinus (kenaf) cultivated in Malaysia. The changes in the whole stalk chemical composition due to different plant age are also examined. In comparison to the kenaf planted in Malaysia and different countries, the locally planted kenaf (Penang) shows some differences in the value of the chemical composition. Increase of plant age from 15 to 19 weeks of kenaf growth are positively decreases the extractive content, but negatively increases the lignin content and decreases the holocellulose content

The influence of Eucalyptus globulus heartwood in pulp production

Mestrado em Engenharia Florestal e dos Recursos Florestais - Instituto Superior de AgronomiaA 18-year-old Eucalyptus globulus tree was used to study the influence of heartwood and sapwood in kraft pulping along different reaction times (1 to 95 min). Heartwood had more extractives (9.8 % vs. 3.9 %) and more xylose content (17.5 % and 13.7 %) compared to sapwood, but no differences were found in total lignin content (23.5 % vs. 24.3 %). After 95 min, heartwood pulps had lower yields (52.4 % vs. 56.7 %) and higher residual lignin content (3.0 % vs. 1.2 %) but no differences were found in sugar content. Sapwood pulps presented higher luminosity (L*, 65 to 80), but no differences at a* and b* values. Two models of delignification kinetics were applied: consecutive and simultaneous. Both models explained well the delignification kinetics of sapwood but the simultaneous model explained better the heartwood delignification. RESUMO ALARGADO Neste trabalho foi usada madeira de Eucalyptus globulus com 18 anos para estudar a influência do cerne e do borne na deslenhificação kraft (170ºC) ao longo de vários tempos de reacção (1 a 95 min). As fracções 20-40 mesh de borne e cerne foram caracterizadas por parâmetros químicos e ópticos. O cerne apresentou maior conteúdo em extractivos (9,8 % vs. 3,9 %), mas idêntico teor em lenhina total (23,5 % vs. 24,3 %) e apresentou uma percentagem mais elevada de xilose em relação ao borne (17,5 % vs. 13,7 %), enquanto o conteúdo em glucose foi superior neste último (81,1 % e 75,1 %). O cerne é mais amarelo que o borne respectivamente, 17 e 14, não apresentando diferenças nos parâmetros L* (83) e a* (3). A madeira de borne, por conter menor teor em extractivos comparativamente ao cerne, apresentou após 95 min de deslenhificação, rendimentos superiores (56,7 % vs. 52,4 %) e menor teor em lenhina residual respectivamente, 3,0 % e 1,2 %. O conteúdo em açucares totais foi semelhante em ambas as amostras: arabinose (0,5 %), manose (1,7 %) e galactose (0,8 %), glucose (84 %) e xilose (13 %). O borne apresentou valores de luminosidade (L*) mais elevados que o cerne, respectivamente, 66,5 e 74,5, não se verificando diferenças quanto aos parâmetros a* e b*. Foram aplicados dois modelos matemáticos baseados numa cinética de 1ª ordem, para explicar a remoção de lenhina. O modelo consecutivo descreveu a reacção de deslenhificação em duas fases: uma fase principal (que nas condições usadas inclui a fase inicial) mais rápida e onde é removida a maior parte da lenhina e uma fase residual, mais lenta. Quando aplicado ao borne, este modelo explicou na fase principal maior extracção de lenhina comparativamente ao cerne (86,0 % vs. 80,0 %), com uma constante de velocidade superior no borne (k = 0,061 min-1 vs. k = 0,048 min-1); na fase residual a extracção foi de respectivamente, 9,0 % e 7,0 % do total de lenhina, com constantes de velocidades correspondentes a 0,017 e 0,007 min-1, permanecendo no cerne cerca de 13,0 % de lenhina na matriz lenhocelulósica e no borne apenas 5,0 %. O modelo simultâneo mostrou a existência de duas fracções da lenhina com diferente reactividade, uma mais reactiva e outra menos reactiva. O borne mostrou 76,0 % da lenhina mais reactiva (L1) que foi removida a uma constante de velocidade k1 de 0,077 min-1, sendo a remoção de 24,0 % da lenhina menos reactiva (L2) feita a um k de 0.018 min-1. No cerne estas fracções representaram respectivamente, 71,0 % e 29,0 %, que apresentaram respectivamente constantes de velocidade: k1 = 0,080 min-1 e k2 = 0,010 min-1. Ambos os modelos explicaram bem a deslenhificação do borne (SQR = 0,041 vs. 0,033), enquanto que o modelo simultâneo explicou melhor a deslenhificação do cerne (SQR = 0,0030). Em conclusão, o cerne foi mais difícil de deslenhificar supondo-se que devido a diferenças anatómicas e química

Finding Voice: A Visual Arts Approach to Engaging Social Change

In Finding Voice, Kim Berman demonstrates how she was able to use visual arts training in disenfranchised communities as a tool for political and social transformation in South Africa. Using her own fieldwork as a case study, Berman shows how hands-on work in the arts with learners of all ages and backgrounds can contribute to economic stability by developing new skills, as well as enhancing public health and gender justice within communities. Berman’s work, and the community artwork her book documents, present the visual arts as a crucial channel for citizens to find their individual voices and to become agents for change in the arenas of human rights and democracy