894 resultados para Voltage reference
Resumo:
Segregering eller segregation är ett fenomen som kan förekomma inom olika områden av samhället. Inom samhällsvetenskaperna kan segregering definieras som det rumsliga åtskiljandet av befolkningsgrupper på urval av ras eller etniskt ursprung, kön, social härkomst, religion, ålder, yrke, osv. Segregering av befolkningsgrupper sker ofta mer eller mindre frivilligt och är motsatsen till integration. Inom partikelteknologi definieras segregering oftast som det rumsliga åtskiljandet av beståndsdelarna i en blandning av olika partiklar. Segregering sker då på urval av bl.a. partiklarnas storlek, densitet, form, elektrostatiska eller mekaniska egenskaper, och kan beskrivas som motsatsen till blandning. Segregeringsmekanismer används för att förklara hur och varför en partikelblandning segregerar samt vad slutresultatet i form av den rumsliga fördelningen av partiklarna blir till följd av att blandningen utsetts för en viss behandling. I denna avhandling har segregering av partikelblandningar och speciellt torra mineralbaserade byggmaterial (t.ex. murbruk) till följd av lagring i siloer studerats. Vid industriell produktion av mineralbaserade byggmaterial används siloer för korttidslagring av slutprodukterna precis innan förpackning. Segregering leder till kraftiga variationer i sammansättningen för partikelströmmen ut ur silon, vilket gör att slutprodukterna inte uppfyller kvalitetskraven och kan därmed inte säljas till kunder. Detta leder till arbetsam och dyr bearbetning (återcirkulation) av produkterna med påföljder för produktionsekonomin samt hållbara utvecklingen. I avhandlingen identifierades de väsentligaste segregeringsmekanismerna för torra mineralbaserade byggmaterial i siloer. Dessutom klargjordes effekterna av materialegenskaper, processbetingelser och siloparametrar. Slutligen behandlas möjliga åtgärder för minskning av partikelsegregering i siloer samt tillämpning av matematiska metoder för simulering av partikelflöden med hjälp av datorer.
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Syövän käyttäytymiseen ja ennusteeseen vaikuttavat monet tekijät, muun muassa muutokset syöpäsoluissa sekä kasvainta ympäröivässä mikroympäristössä. Tutkimuksen tavoitteena oli tutkia uusia prediktiivisiä ja prognostisia ennustetekijöitä syöpäsoluissa (EGFR geenikopiomäärä, EGFR, onkogeeni pim-1) sekä syöpäkasvaimen mikroympäristöön kuuluvissa imuteissä (CLEVER-1, podoplaniini), makrofageissa (CD68, CLEVER-1) ja T lymfosyyteissä (CD3) kolorektaalisyövässä. Lisäksi tutkittiin imuteiden molekulaarisia ominaisuuksia tarkemmin (CD73, LYVE-1, podoplaniini) kuten myös lymfosyyttien ja dendriittisolujen liikennöintiä imuteissä. Tutkimustulokset osoittavat että korkea Pim-1 ekspressiotaso, suuri peritumoraalinen CD68+ makrofagimäärä sekä varhaisen vaiheen taudissa suuri CLEVER-1+ peritumoraalinen makrofagimäärä ovat hyvän ennusteen tekijöitä kolorektaalisyövässä. Metastaattisessa taudissa sen sijaan suuri määrä CLEVER-1+ makrofageja, sekä intra- että peritumoraalisesti, liittyy huonoon tautiennusteeseen. EGFR geenikopiomäärä, EGFR proteiinipitoisuuden ohjaaman hopea in situ hybridisaatiomenetelmän avulla määritettynä, ennusti vastetta anti-EGFR hoidolle metastaattisessa kolorektaalisyövässä tarkemmin kuin nykyisin rutiinisti käytössä oleva KRAS määritys. Lisäksi havaittiin että imutiet ovat monimuotoisia imutiemarkkeri ekspressionsa suhteen sekä normaali- että syöpäkudoksissa. CD73 molekyylin funktio imuteissä poikkesi selvästi molekyylin funktiosta verisuonissa. Yhteenvetona voidaan todeta että kolorektaalisyövän ennusteeseen vaikuttavien tekijöiden merkitys vaihtelee taudin levinneisyysasteen sekä imuteiden että makrofagien sijainnin perusteella. Korkea Pim-1 ilmentyminen on yhteydessä hyvään kolorektaalisyöpäennusteeseen. Lisäksi EGFR geenikopiomäärä osoittautui lupaavaksi uudeksi prediktiiviseksi ennustetekijäksi KRAS villintyypin metastaattista kolorektaalisyöpää sairastavilla potilailla.
Resumo:
The theme of the research is the development of the domain of marketing knowledge in the design of agricultural machinery. It is developed throughout the design of agricultural machinery in order to identify the corporate and customers needs and to develop strategies to satisfy these needs. The central problem of the research questions which marketing tools to apply on pre-development process of farm machinery, in order to increase the market value of the products and of the company and, consequently, generate competitive advantage to the manufacturers of agricultural machinery. As methodology, it was developed bibliographical research and multicase study of the development process of agricultural machinery developed by small, medium and large companies and the academy. As a result, a marketing reference model was elaborated for the pre-development stage of agricultural machinery, which outlines the activities, tasks, mechanisms and controls that can be used in strategic planning and in products planning of agricultural machinery manufacturers, contributing to explain the explicit knowledge in the marketing field.
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Evapotranspiration is the process of water loss of vegetated soil due to evaporation and transpiration, and it may be estimated by various empirical methods. This study had the objective to carry out the evaluation of the performance of the following methods: Blaney-Criddle, Jensen-Haise, Linacre, Solar Radiation, Hargreaves-Samani, Makkink, Thornthwaite, Camargo, Priestley-Taylor and Original Penman in the estimation of the potential evapotranspiration when compared to the Penman-Monteith standard method (FAO56) to the climatic conditions of Uberaba, state of Minas Gerais, Brazil. A set of 21 years monthly data (1990 to 2010) was used, working with the climatic elements: temperature, relative humidity, wind speed and insolation. The empirical methods to estimate reference evapotranspiration were compared with the standard method using linear regression, simple statistical analysis, Willmott agreement index (d) and performance index (c). The methods Makkink and Camargo showed the best performance, with "c" values of 0.75 and 0.66, respectively. The Hargreaves-Samani method presented a better linear relation with the standard method, with a correlation coefficient (r) of 0.88.
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The consideration of the streamflow seasonality has a high potential to improve the water use. In order to give subsidies to the optimization of water use, it was evaluated the impact of the change of reference annual streamflow by the monthly streamflows in the potential water use throughout the hydrography of Paracatu sub-Basin. It was evaluated the impact on Q7,10 (lowest average streamflow during a 7-day period with an average recurrence of 10 years) and on Q95 (permanent flow present 95% of the time). The use of monthly streamflow to substitute the annual streamflow had a high potential of improvement of water resources use in the sub-Basin studied. The use of monthly Q 7,10 in substitution of annual Q 7,10 increases the potential water use that vary from about 10% in the months of lower water availability to values exceeding 200% in the months with higher availability of surface water resources. The use of monthly Q95 in substitution of the annual Q95 implies in changes oscillating from reduction of 37% in months of higher water restriction to values exceeding 100% in the months of higher availability, so the use of monthly Q95 instead of the annual Q95 enables the more rational and safe use of water resources.
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One approach to verify the adequacy of estimation methods of reference evapotranspiration is the comparison with the Penman-Monteith method, recommended by the United Nations of Food and Agriculture Organization - FAO, as the standard method for estimating ET0. This study aimed to compare methods for estimating ET0, Makkink (MK), Hargreaves (HG) and Solar Radiation (RS), with Penman-Monteith (PM). For this purpose, we used daily data of global solar radiation, air temperature, relative humidity and wind speed for the year 2010, obtained through the automatic meteorological station, with latitude 18° 91' 66" S, longitude 48° 25' 05" W and altitude of 869m, at the National Institute of Meteorology situated in the Campus of Federal University of Uberlandia - MG, Brazil. Analysis of results for the period were carried out in daily basis, using regression analysis and considering the linear model y = ax, where the dependent variable was the method of Penman-Monteith and the independent, the estimation of ET0 by evaluated methods. Methodology was used to check the influence of standard deviation of daily ET0 in comparison of methods. The evaluation indicated that methods of Solar Radiation and Penman-Monteith cannot be compared, yet the method of Hargreaves indicates the most efficient adjustment to estimate ETo.
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The main advantage of organic electronics over the more widespread inorganic counterparts lies not in the electrical performance, but rather in the solution processability that opens up for low-cost flexible electronics (e.g. displays, sensors and smart tags) fabricated by using printing techniques. Replacing the commonly used laboratory-scale fabrication techniques with mass-printing techniques is, however, truly challenging, especially when low-voltage operation is required. In this thesis it is, nevertheless, demonstrated that low-voltage organic transistors can be fully printed with a similar performance to that of transistors made by laboratory scale techniques. The use of an ion-modulated type of organic field effect transistor (OFET) not only enabled low-voltage operation and printability, but was also found to result in low sensitivity to the surface roughness of the substrate. This allows not only the use of low-cost plastic substrates, but even the use of paper as a substrate. However, while absorption into the porous paper surface is advantageous in a graphical printing process, by reducing the spreading and the coffee-stain effect and by improving the adhesion, it provides great challenges when applying thin electrically active layers. In spite of these difficulties we were able to demonstrate the first low-voltage OFET to be fabricated on paper. We have also shown that low-cost incandescent lamps can be used for sintering printed metal-nanoparticles, and that the process was especially suitable on paper and compatible with a roll-to-roll manufacturing process.
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The focus in this thesis is to study both technical and economical possibilities of novel on-line condition monitoring techniques in underground low voltage distribution cable networks. This thesis consists of literature study about fault progression mechanisms in modern low voltage cables, laboratory measurements to determine the base and restrictions of novel on-line condition monitoring methods, and economic evaluation, based on fault statistics and information gathered from Finnish distribution system operators. This thesis is closely related to master’s thesis “Channel Estimation and On-line Diagnosis of LV Distribution Cabling”, which focuses more on the actual condition monitoring methods and signal theory behind them.
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Objective: To evaluate the characteristics of thyroid carcinoma cases treated at a reference hospital for cancer between 2008 and 2010.Methods: we studied 807 cases and analyzed the following clinicopathologic variables: symptoms, risk factors, diagnostic tests, staging, histological type, treatment performed and complications.Results: Females were more affected, with 660 cases (82%). The average age at diagnosis was 44.5 years. Prior exposure to ionizing radiation was reported by 22 (3%) patients, a family history of thyroid cancer by 89 (11%), and 289 (36%) individuals reported other types of cancer in the family. The fine needle aspiration biopsy was the main parameter for surgical indication and was suggestive of carcinoma in 463 patients (57%). Papillary carcinoma was the most common histological type, with 780 cases (96.6%). There were 728 (90%) total thyroidectomies, 43 (5.3%) reoperations or partial thyroidectomies followed by totalization, 23 (2.8%) extended thyroidectomies and only 13 (1.6%) partial thyroidectomies (lobectomy with isthmectomy). Neck dissection associated with thyroidectomy was done in 158 patients (19.5%). We observed a predominance of tumors classified as T1 in 602 (74.6%) patients. Transient hypocalcemia was the most frequent complication.Conclusion: The results show that the worldwide increase in the incidence of thyroid cancer has changed the profile of patients seen at a referral service. In addition, there were changes in the type of surgical treatment used, with increased use of total thyroidectomy in relation to partial and subtotal ones, and decreased use of elective neck dissections.
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Objective: To evaluate the epidemiological profile and the operative complications of patients undergoing gynecological operations for benign diseases in a tertiary public hospital in the state of Roraima, Brazil. Methods: We conducted a retrospective survey through the analysis of 518 records of patients submitted to gynecological operations between January and June 2012. We included the three major operations during this period (n = 175): hysterectomy, colpoperineoplasty and suburethral sling placement. We excluded 236 cases of tubal ligation and 25 cases where it was not possible to access to medical records. Results: The mean age was 47.6 years; the education level of most patients was completed junior high (36.6%); 77% were from the State capital, 47.4% were in stable relationships and 26.3% were housewives. The majority of patients had given birth three or more times (86.6%), with previous vaginal delivery in 50.2%, and cesarean delivery, 21%. The main diagnostic indications for surgical treatment were uterine myoma (46.3%), urinary incontinence (27.4%) and genital dystopias (17.7%). We found three cases (1.7%) of high-grade intraepithelial lesions on Pap smear. The most common procedure was total hysterectomy (19.8%), 15.5% vaginally. The most common complication was wound infection (2.2%). Conclusion: Women undergoing gynecological operations due to benign disease had a mean age of 47 years, most had levels of basic education, came from the capital, were in stable relationships, predominantly housewives, multiparous and showed low operative complication rates.
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Fuel cells are a promising alternative for clean and efficient energy production. A fuel cell is probably the most demanding of all distributed generation power sources. It resembles a solar cell in many ways, but sets strict limits to current ripple, common mode voltages and load variations. The typically low output voltage from the fuel cell stack needs to be boosted to a higher voltage level for grid interfacing. Due to the high electrical efficiency of the fuel cell, there is a need for high efficiency power converters, and in the case of low voltage, high current and galvanic isolation, the implementation of such converters is not a trivial task. This thesis presents galvanically isolated DC-DC converter topologies that have favorable characteristics for fuel cell usage and reviews the topologies from the viewpoint of electrical efficiency and cost efficiency. The focus is on evaluating the design issues when considering a single converter module having large current stresses. The dominating loss mechanism in low voltage, high current applications is conduction losses. In the case of MOSFETs, the conduction losses can be efficiently reduced by paralleling, but in the case of diodes, the effectiveness of paralleling depends strongly on the semiconductor material, diode parameters and output configuration. The transformer winding losses can be a major source of losses if the windings are not optimized according to the topology and the operating conditions. Transformer prototyping can be expensive and time consuming, and thus it is preferable to utilize various calculation methods during the design process in order to evaluate the performance of the transformer. This thesis reviews calculation methods for solid wire, litz wire and copper foil winding losses, and in order to evaluate the applicability of the methods, the calculations are compared against measurements and FEM simulations. By selecting a proper calculation method for each winding type, the winding losses can be predicted quite accurately before actually constructing the transformer. The transformer leakage inductance, the amount of which can also be calculated with reasonable accuracy, has a significant impact on the semiconductor switching losses. Therefore, the leakage inductance effects should also be taken into account when considering the overall efficiency of the converter. It is demonstrated in this thesis that although there are some distinctive differences in the loss distributions between the converter topologies, the differences in the overall efficiency can remain within a range of a few percentage points. However, the optimization effort required in order to achieve the high efficiencies is quite different in each topology. In the presence of practical constraints such as manufacturing complexity or cost, the question of topology selection can become crucial.
Resumo:
PURPOSE: To evaluate changes to the pelvic floor of primiparous women with different delivery modes, using three-dimensional ultrasound. METHODS: A prospective cross-sectional study on 35 primiparae divided into groups according to the delivery mode: elective cesarean delivery (n=10), vaginal delivery (n=16), and forceps delivery (n=9). Three-dimensional ultrasound on the pelvic floor was performed on the second postpartum day with the patient in a resting position. A convex volumetric transducer (RAB4-8L) was used, in contact with the large labia, with the patient in the gynecological position. Biometric measurements of the urogenital hiatus were taken in the axial plane on images in the rendering mode, in order to assess the area, anteroposterior and transverse diameters, average thickness, and avulsion of the levator ani muscle. Differences between groups were evaluated by determining the mean differences and their respective 95% confidence intervals. The proportions of levator ani muscle avulsion were compared between elective cesarean section and vaginal birth using Fisher's exact test. RESULTS: The mean areas of the urogenital hiatus in the cases of vaginal and forceps deliveries were 17.0 and 20.1 cm², respectively, versus 12.4 cm² in the Control Group (elective cesarean). Avulsion of the levator ani muscle was observed in women who underwent vaginal delivery (3/25), however there was no statistically significant difference between cesarean section and vaginal delivery groups (p=0.5). CONCLUSION: Transperineal three-dimensional ultrasound was useful for assessing the pelvic floor of primiparous women, by allowing pelvic morphological changes to be differentiated according to the delivery mode.
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PURPOSE: To establish reference values for the first trimester uterine artery resistance index (UtA-RI) and pulsatility index (UtA-PI) in healthy singleton pregnant women from Northeast Brazil. METHODS: A prospective observational cohort study including 409 consecutive singleton pregnancies undergoing routine early ultrasound screening at 11 - 14 weeks of gestation was performed. The patients responded to a questionnaire to assess maternal epidemiological characteristics. The left and right UtA-PI and UtA-RI were examined by color and pulsed Doppler by transabdominal technique and the mean UtA-PI, mean UtA-RI and the presence of bilateral protodiastolic notching were recorded. Quartile regression was used to estimate reference values. RESULTS: The mean±standard deviation UtA-RI and UtA-PI were 0.7±0.1 and 1.5±0.5, respectively. When segregated for gestation age, mean UtA-PI was 1.6±0.5 at 11 weeks, 1.5±0.6 at 12 weeks, 1.4±0.4 at 13 weeks and 1.3±0.4 at 14 weeks' gestation and mean UtA-RI was 0.7±0.1 at 11 weeks, 0.7±0.1 at 12 weeks, 0.6±0.1 at 13 weeks and 0.6±0.1 at 14 weeks' gestation. Uterine artery bilateral notch was present in 261 (63.8%) patients. We observed that the 5th and 95th percentiles of the UtA-PI and UtA-RI uterine arteries were 0.7 and 2.3 and, 0.5 and 0.8, respectively. CONCLUSION: Normal reference range of uterine artery Doppler in healthy singleton pregnancies from Northeast Brazil was established. The 95th percentile of UtA-PI and UtA-RI values may serve as a cut-off for future prediction of pregnancy complications studies (i.e., pre-eclampsia) in Northeast Brazil.
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PURPOSE: To describe maternal and neonatal outcomes in pregnant women undergoing hemodialysis in a referral center in Brazilian Southeast side.METHODS: Retrospective and descriptive study, with chart review of all pregnancies undergoing hemodialysis that were followed-up at an outpatient clinic of high- risk prenatal care in Southeast Brazil.RESULTS: Among the 16 women identified, 2 were excluded due to follow-up loss. In 14 women described, hypertension was the most frequent cause of chronic renal failure (half of cases). The majority (71.4%) had performed hemodialysis treatment for more than one year and all of them underwent 5 to 6 hemodialysis sessions per week. Eleven participants had chronic hypertension, 1 of which was also diabetic, and 6 of them were smokers. Regarding pregnancy complications, 1 of the hypertensive women developed malignant hypertension (with fetal growth restriction and preterm delivery at 29 weeks), 2 had acute pulmonary edema and 2 had abruption placenta. The mode of delivery was cesarean section in 9 women (64.3%). All neonates had Apgar score at five minutes above 7.CONCLUSIONS: To improve perinatal and maternal outcomes of women undergoing hemodialysis, it is important to ensure multidisciplinary approach in referral center, strict control of serum urea, hemoglobin and maternal blood pressure, as well as close monitoring of fetal well-being and maternal morbidities. Another important strategy is suitable guidance for contraception in these women.