954 resultados para Direct Current Machine Control
Resumo:
An improved defoamer dosage procedure and a more efficient dosing point to the approach system were studied in this thesis. Their influence on paper machine wet end operations was investigated. The improved defoamer dosing procedure was examined at UMP-Kymmene Tervasaari PM8. Air content and its controlling methods at the paper machine were studied in the literature survey. Also the influence of dissolved gases and entrained air in the papermaking furnish were introduced. Feeding methods – a TrumpJet chemical mixer and traditional feeding devices – were reviewed. The defoamer’s functioning methods were studied. The influence of the use of defoamers was estimated based on the main selected wet end operations. In the experimental part, defoamer mixing with a traditional feeding method and two improved mixing stages were compared based on the air content profiles in PM8’s approach system. The reference dosage procedure was PM8’s old dosing system. The first dosage procedure in the comparison involved two TrumpJet chemical mixers installed on the bottom wire trays. The second element of comparison involved the improvement brought by a third TrumpJet chemical mixer installed on the top wire tray. This second comparison of the efficient defoamer feeding concept was made at a higher production speed of PM8. The air content control situation was also studied at the higher production speed. In addition the connection between the defoamer and air content was observed and a mill-scale system was studied. The economical benefits of the new dosing procedure were also reviewed. Air content profiles of short circulation were measured in the reference situation and the two comparison points of the study. These air content measurements proved the main gas load is introduced to PM8's paper furnish from the white water tray. Thick stock air content was not essential when the air volume flow was considered. The improved defoamer dosing procedure made lower dosage amounts possible. Compared with the traditional feeding system, the new defoamer feeding concept made only few direct improvements to the wet end operations and the produced paper itself. The lower defoamer need was noticed to have a positive influence on hydrophobic sizing and paper defects. The surfaces of the white water tanks and the operation of pumps were assessed based on the density variations of the suspension. The temperature in the white water silo was stated to have a significant influence on the air content measured in the first centrifugal cleaning stage.
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Osteoclasts are cells responsible for bone resorption. These cells undergo extensive membrane re-organization during their polarization for bone resorption and form four distinct membrane domains, namely the ruffled border, the basolateral membrane, the sealing zone and the functional secretory domain. The endocytic/biosynthetic pathway and transcytotic route(s) are important for the resorption process, since the endocytic/biosynthetic pathway brings the specific vesicles to the ruffled border whereas the transcytotic flow is believed to transport the degraded bone matrix away from the resorption lacuna to the functional secretory domain. In the present study, we found a new transcytotic route from the functional secretory domain to the ruffled border, which may compensate membrane loss from the ruffled border during the resorption process. We also found that lipid rafts are essential for the ruffled border-targeted late endosomal pathways. A small GTP-binding protein, Rab7, has earlier been shown to regulate the late steps of the endocytic pathway. In bone-resorbing osteoclasts it is involved in the formation of the ruffled border, which displays several features of late endosomal membranes. Here we discovered a new Rab7-interacting protein, Rac1, which is another small GTP-binding protein and binds to the GTP-form of Rab7 in vitro. We demonstrated further that Rab7 colocalizes with Rac1 at the fusion zone of the ruffled border in bone-resorbing osteoclasts. In other cell types, such as fibroblast-like cells, this colocalization is mainly perinuclear. Because Rac1 is known to control the actin cytoskeleton through its effectors, we suggest that the Rab7-Rac1 interaction may mediate late endosomal transport between microtubules and microfilaments, thus enabling endosomal vesicles to switch tracks from microtubules to microfilaments before their fusion to the ruffled border. We then studied the role of Rab-Rac1 interaction in the slow recycling pathway. We revealed that Rac1 also binds directly to Rab11 and to some other but not all Rab-proteins, suggesting that Rab-Rac1 interaction could be a general regulatory mechanism to direct the intracellular vesicles from microtubule mediated transport to actin filament mediated transport and vice versa. On the basis of our results we thus propose a new hypothesis for these GTPases in the regulation of intracellular membrane flow.
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Background: None of the HIV T-cell vaccine candidates that have reached advanced clinical testing have been able to induce protective T cell immunity. A major reason for these failures may have been suboptimal T cell immunogen designs. Methods: To overcome this problem, we used a novel immunogen design approach that is based on functional T cell response data from more than 1,000 HIV-1 clade B and C infected individuals and which aims to direct the T cell response to the most vulnerable sites of HIV-1. Results: Our approach identified 16 regions in Gag, Pol, Vif and Nef that were relatively conserved and predominantly targeted by individuals with reduced viral loads. These regions formed the basis of the HIVACAT T-cell Immunogen (HTI) sequence which is 529 amino acids in length, includes more than 50 optimally defined CD4+ and CD8+ T-cell epitopes restricted by a wide range of HLA class I and II molecules and covers viral sites where mutations led to a dramatic reduction in viral replicative fitness. In both, C57BL/6 mice and Indian rhesus macaques immunized with an HTI-expressing DNA plasmid (DNA.HTI) induced broad and balanced T-cell responses to several segments within Gag, Pol, and Vif. DNA.HTI induced robust CD4+ and CD8+ T cell responses that were increased by a booster vaccination using modified virus Ankara (MVA.HTI), expanding the DNA.HTI induced response to up to 3.2% IFN-γ T-cells in macaques. HTI-specific T cells showed a central and effector memory phenotype with a significant fraction of the IFN-γ+ CD8+ T cells being Granzyme B+ and able to degranulate (CD107a+). Conclusions: These data demonstrate the immunogenicity of a novel HIV-1 T cell vaccine concept that induced broadly balanced responses to vulnerable sites of HIV-1 while avoiding the induction of responses to potential decoy targets that may divert effective T-cell responses towards variable and less protective viral determinants.
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The purpose of this study was to improve PM7’s basis weight CD profile in Stora Enso’s Berghuizer mill and to search mechanical defects which affect to the formation of the basis weight CD profile. In the theoretical part PM7’s structure was presented and the formation of the basis weight and caliper CD profiles was examined as well as disturbances which are affecting to the formation. The function of the control system was scrutinised for the side of CD profiles as well as the formation of the measured CD profiles. Tuning of the control system was examined through the response model and filtering. Specification of the response model and filtering was explained and how to determine 2sigma statistical number. In the end of the theoretical part ATPA hardware and a new profile browser were introduced. In the experimental part focus was in the beginning to search and remove mechanical defects which are affecting to CD profiles. The next step was to verify the reliability of the online measurements, to study the stability of the basis weight CD profile and to find out so called fingerprint, a basis weight CD profile which is unique for each paper machine. New response model and filtering value for basis weight CD profile was determined by bump tests. After a follow up period the affect of the new response model and filtering was analysed.
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Pfaffic acid, a marker of Hebanthe eriantha (Brazilian ginseng), was first isolated in 1983 but is not yet commercially available. This lack of availability compromises the quality control of this plant and its derivatives. This paper proposes a process for pfaffic acid isolation from roots of H. eriantha at a purity suitable for analytical purposes. The steps involved in this process included extraction, hydrolysis, fractionation and purification by preparative HPLC. This process led to isolation of pfaffic acid with a chromatographic purity of 98.5% in a 0.25% yield from dried roots of H. eriantha; this yield is more than forty times higher than that of the current method in the literature.
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The Direct Black 22 dye was electrooxidized at 30 mA cm-2 in a flow cell using a BDD or β-PbO2 anode, varying pH (3, 7, 11), temperature (10, 25, 45 °C), and [NaCl] (0 or 1.5 g L-1). In the presence of NaCl, decolorization rates were similar for all conditions investigated, but much higher than predicted through a theoretical model assuming mass-transport control; similar behavior was observed for COD removal (at pH 7, 25 °C), independently of the anode. With no NaCl, COD removals were also higher than predicted with a theoretical model, which suggests the existence of distinct dye degradation pathways.
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Noctuids are phytophagous lepidopterans with some species causing significant damage to agriculture. The host plants, in turn, have developed defense mechanisms to cope with them, for instance chemical defenses. In this study we review the literature on plant volatiles induced by noctuids, and discuss the methodologies used to induce the production of volatiles that are usually employed in plant defense mechanisms. Future prospects involving this line of research in pest control are also discussed.
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The profitability on transportation field has been low for a long time. The re-cession that started in the fall of 2008 has caused even more trouble to transportation companies as the number of transportations has gone down and the competition has gotten tougher since the time before the recession. Because the low profitability level does not allow competing with prices, transportation companies must come up with other means to differ from their competitors. The main goal of the research was to find out how a small and medium-sized enterprise (SME) on transportation field should manage its customer relationships. Due to limited resources, companies should direct their resources to serving their most valuable customers. Companies should first make a determination of their customer base. This works as a base for establishing customer portfolios, in other words making customer groups based on e.g. profitability, buying volumes and loyalty. Companies can gain competitive advantage also by improving their service quality. Important information regarding the selection criteria of a transporta-tion company, transaction methods, service time and accessibility of person-nel, customers’ expectations on transportation company’s personnel, utiliza-tion of IT-solutions as a part of transportation service, the image of a transportation company and necessity of quality control meetings was gathered for this research by interviewing customers. By utilizing this information, transportation company can adapt its service offering to equal the customer needs and expectations better. A service process example was created to improve the service quality of the transportation company. It shows the whole process from the customer sending the transportation order to the point when the customer receives an invoice from the transportation company. The example process shows the most fragile stages of the service process: the interaction points. An example of this is when the driver and the customer meet at the unloading place. The results show that even a SME can have the opportunity to succeed in competitive markets by managing CRM. Expensive software are usually out of reach of a SME, but having a CRM software does not automatically guar-antee success in customer relationship management. Small and medium-sized firms can commit their current customers and recruit new customers by utilizing customer knowledge, offering top quality service, being innovative and offering functional services.
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Tässä diplomityössä esitellään robotisoinnin teoria ja robottisolun oheislaitteet, vaihtoehdot, toiminta ja turvallisuus. Joustavalla tuotantosolulla tarkoitetaan automaattista valmistusjärjestelmää, jossa on useita toisiinsa liitettyjä koneita yhteisellä ohjausjärjestelmällä. Solun komponentteja ovat tuotantolaitteet ja -koneet, ohjausjärjestelmät, valvontalaitteet ja anturit, toimi- ja säätölaitteet sekä ohjelmointijärjestelmä. Joustavaa tuotantosolua voidaan kehittää tehostamalla työntekijöiden koulutusta, ohjelmointia, asetusten tekemistä ja layouttia. Diplomityöhön liittyvä kehitystehtävä koskee heinäveteläisen alihankintakonepajan, Metalliset Oy:n, tuotannon tehostamista robotisoinnin avulla. Metalliset Oy:n joustavan särmäyssolun kehittämiskeinoiksi valittiin nykyisen järjestelmän tehostaminen, uuden tuotantosolun luominen olemassa olevia laitteita hyödyntäen ja tulevaisuuden tuotantosolun kehittäminen. Vertailussa parhaimmaksi osoittautui uuden tuotantosolun luominen olemassa olevia laitteita hyödyntäen.
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Direct leaching is an alternative to conventional roast-leach-electrowin (RLE) zinc production method. The basic reaction of direct leach method is the oxidation of sphalerite concentrate in acidic liquid by ferric iron. The reaction mechanism and kinetics, mass transfer and current modifications of zinc concentrate direct leaching process are considered. Particular attention is paid to the oxidation-reduction cycle of iron and its role in direct leaching of zinc concentrate, since it can be one of the limiting factors of the leaching process under certain conditions. The oxidation-reduction cycle of iron was experimentally studied with goal of gaining new knowledge for developing the direct leaching of zinc concentrate. In order to obtain this aim, ferrous iron oxidation experiments were carried out. Affect of such parameters as temperature, pressure, sulfuric acid concentration, ferrous iron and copper concentrations was studied. Based on the experimental results, mathematical model of the ferrous iron oxidation rate was developed. According to results obtained during the study, the reaction rate orders for ferrous iron concentration, oxygen concentration and copper concentration are 0.777, 0.652 and 0.0951 respectively. Values predicted by model were in good concordance with the experimental results. The reliability of estimated parameters was evaluated by MCMC analysis which showed good parameters reliability.
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In recent years, the network vulnerability to natural hazards has been noticed. Moreover, operating on the limits of the network transmission capabilities have resulted in major outages during the past decade. One of the reasons for operating on these limits is that the network has become outdated. Therefore, new technical solutions are studied that could provide more reliable and more energy efficient power distributionand also a better profitability for the network owner. It is the development and price of power electronics that have made the DC distribution an attractive alternative again. In this doctoral thesis, one type of a low-voltage DC distribution system is investigated. Morespecifically, it is studied which current technological solutions, used at the customer-end, could provide better power quality for the customer when compared with the current system. To study the effect of a DC network on the customer-end power quality, a bipolar DC network model is derived. The model can also be used to identify the supply parameters when the V/kW ratio is approximately known. Although the model provides knowledge of the average behavior, it is shown that the instantaneous DC voltage ripple should be limited. The guidelines to choose an appropriate capacitance value for the capacitor located at the input DC terminals of the customer-end are given. Also the structure of the customer-end is considered. A comparison between the most common solutions is made based on their cost, energy efficiency, and reliability. In the comparison, special attention is paid to the passive filtering solutions since the filter is considered a crucial element when the lifetime expenses are determined. It is found out that the filter topology most commonly used today, namely the LC filter, does not provide economical advantage over the hybrid filter structure. Finally, some of the typical control system solutions are introduced and their shortcomings are presented. As a solution to the customer-end voltage regulation problem, an observer-based control scheme is proposed. It is shown how different control system structures affect the performance. The performance meeting the requirements is achieved by using only one output measurement, when operating in a rigid network. Similar performance can be achieved in a weak grid by DC voltage measurement. An additional improvement can be achieved when an adaptive gain scheduling-based control is introduced. As a conclusion, the final power quality is determined by a sum of various factors, and the thesis provides the guidelines for designing the system that improves the power quality experienced by the customer.
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The etiology and epidemiology of Pythium root rot in hydroponically-grown crops are reviewed with emphasis on knowledge and concepts considered important for managing the disease in commercial greenhouses. Pythium root rot continually threatens the productivity of numerous kinds of crops in hydroponic systems around the world including cucumber, tomato, sweet pepper, spinach, lettuce, nasturtium, arugula, rose, and chrysanthemum. Principal causal agents include Pythium aphanidermatum, Pythium dissotocum, members of Pythium group F, and Pythium ultimum var. ultimum. Perspectives are given of sources of initial inoculum of Pythium spp. in hydroponic systems, of infection and colonization of roots by the pathogens, symptom development and inoculum production in host roots, and inoculum dispersal in nutrient solutions. Recent findings that a specific elicitor produced by P. aphanidermatum may trigger necrosis (browning) of the roots and the transition from biotrophic to necrotrophic infection are considered. Effects on root rot epidemics of host factors (disease susceptibility, phenological growth stage, root exudates and phenolic substances), the root environment (rooting media, concentrations of dissolved oxygen and phenolic substances in the nutrient solution, microbial communities and temperature) and human interferences (cropping practices and control measures) are reviewed. Recent findings on predisposition of roots to Pythium attack by environmental stress factors are highlighted. The commonly minor impact on epidemics of measures to disinfest nutrient solution as it recirculates outside the crop is contrasted with the impact of treatments that suppress Pythium in the roots and root zone of the crop. New discoveries that infection of roots by P. aphanidermatum markedly slows the increase in leaf area and whole-plant carbon gain without significant effect on the efficiency of photosynthesis per unit area of leaf are noted. The platform of knowledge and understanding of the etiology and epidemiology of root rot, and its effects on the physiology of the whole plant, are discussed in relation to new research directions and development of better practices to manage the disease in hydroponic crops. Focus is on methods and technologies for tracking Pythium and root rot, and on developing, integrating, and optimizing treatments to suppress the pathogen in the root zone and progress of root rot.
Resumo:
Aqueous extracts of several plant species have shown promising in controlling root-knot nematode, Meloidogyne incognita (Kofoid & White), one of the most limiting agents for carrot cultivation. The current study evaluated the effect of aqueous extracts from seven botanical species applied to 40, 50, 60, 70 and 80 days after sowing 'Nantes' carrots in soil infested with root-knot nematode. Three other treatments included cassava wastewater, distilled water (control), which were applied in the same periods of the extracts application, in addition to carbofuran 50G (80Kg/ha), which was applied once at 60 days after carrot sowing. Evaluations were performed at 90 days after inoculation to determine shoot and root fresh weight, as well as the diameter and the length of principal roots and the number of galls on primary and secondary roots. Plants treated with cassava wastewater, extracts of Ricinus communis L. seeds, Crotalaria juncea L. seeds, R. communis leaves + branches + fruits, Chenopodium ambrosioides L. leaves + branches + inflorescences and Azadirachta indica A. Juss. seeds showed the highest rates of total weight (root + shoot) and shoot weight. The extract of R. communis leaves + branches + fruits provides the highest total root weight and principal root diameter. Cassava wastewater and extracts of R. communis seeds provided the highest principal root weight. The extract of R. communis seeds and cassava wastewater can be considered promising for the alternative control of M. incognita.
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ABSTRACT Losses due to soybean anthracnose, caused by Colletotrichum truncatum, have not been systematically quantified in the field, and the efficacy of chemical control of this disease is not known. This study shows an estimate of losses associated with the disease in soybean crops in the north of the country. Two trials with cv. M9144 RR were carried out in commercial fields in Tocantins State in the 2010/2011 and 2011/2012 growing seasons, in randomized blocks, with four replicates. Foliar applications were performed on plants at R1/R2 and R5.2 stages, employing CO2-pressurized equipment and application volume of 200 L ha-1. Nine fungicides and one untreated control were compared, and the disease gradients in the two seasons were obtained. The percentage of infected pods was calculated at the R6 stage. Grain yield ranged from 3,288 to 3,708 kg/ha in the untreated plots in 2010/2011 and 2011/2012, respectively, and from 3,282 to 4,110 kg/ha in the treated plots. In the 2010/2011 season, only azoxystrobin + cyproconazole significantly reduced the disease incidence, compared to untreated control plots, not differing from the remaining treatments. In the 2011/2012 season, there were no significant differences between treated and untreated plots. Highly significant correlations (p < 0.01) were found between yield and soybean anthracnose incidence on pods in both years (r = -0.85). For each 1% increment in the disease incidence, c. 90 kg/ha of soybean grain were lost. The current study determined that significant losses due to anthracnose occur in commercial crops in the north of the country and highlighted the limitation of chemical control as anthracnose management method.
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The aim of this study was to create a Balanced Scorecard to the DigiCup solution. The first goal was to create process descriptions to the few critical processes. The second goal was to define appropriate measurements, according to customer survey as well as following the Balanced Scorecard process description, to manage the critical success factors. The overall goal of this study was to create a performance measurement system for the solution which guides the operation towards continuous improvement. This study was conducted by using both qualitative and quantitative methods, and the analysis was done by using a case study method. The material was gathered from the current customers, the management and the employees using structured, semi-structured and open group and individual interviews. The current customers were divided into retailers and direct customers of the DigiCup solution. The questions which the customers were asked were related to the information about interviewee, company, business strategy, market, satisfaction survey and future requirements. The management defined the strategy and took part in specifying the perspectives, objectives and measurements to the Balanced Scorecard of the DigiCup solution. The employees participated into the choosing of the metrics. The material consisted from altogether sixteen interviews. At the beginning of the study the product development, the order-delivery as well as the printing processes was chosen to be the critical processes of the DigiCup solution. These processes were concentrated on already in the literature review while trying to find the characteristics of these processes as well as the critical success factors and the appropriate measurements, which could be utilized when creating the Balanced Scorecard to the DigiCup solution according to the customer survey. The appropriate perspectives, objectives and measurements were found to the DigiCup solution. The chosen measures works as a basis for the development of IT-reporting tool. As a conclusion it can be stated that when discussing a new business, where the objectives are changing according to which development’s phases the company is in, the measurement should be updated often enough.