970 resultados para Single reaction interface flow analysis


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Tämän case -tutkimuksen tarkoituksena on kartoittaa tekstiili- ja vaatetusmateriaalien ekologista elinjakson hallintaa Talousvarikon toiminnoissa ja tutkimalla mahdollisuuksia soveltaa saatuja tuloksia. Talousvarikko on Puolustusvoimien Materiaalilaitoksen alainen järjestelmävastuuvarikko, jonka tehtävänä on varusmiesten ja kadettien vaatetuksen hankinta- ja ylläpitotoiminnot. Talousvarikko jakautuu neljälle paikkakunnalle. Hämeenlinnassa on hankinta-, hallinto- ja materiaaliosasto. Säkylässä, Mikkelissä ja Sodankylässä ovat vaatetuskorjaamot. Tekstiilimateriaalien elinkaariajattelussa tarkastellaan raaka-aineiden jaottelua ja maailman kuitutuotantoa. Tekstiilikuidut jaotellaan luonnon- ja tekokuituihin. Luonnonkuidut ovat pääosin luonnon raaka-aineita ja tekokuidut ovat synteettisesti valmistettuja. Tekstiilikuitujen- ja materiaalien vaikutus ekologiseen elinjakson hallinnan vaiheisiin on riippuvainen raaka-aineidenalkuperästä. Vaatetus- ja tekstiilimateriaalin elinkaari muodostuu tuotekehityksestä, hankinnasta, valmistuksesta, käytöstä, huollosta ja hylkäyksestä. Ekologista elinjakson hallintaa tarkastellaan materiaalivirta- ja elinkaarianalyysien kautta. Elinkaarianalyysin tarkastelu painottuu vaikutusluokkien arvottamiseen ja materiaalivirta-analyysissä tarkastellaan ainevirtoja ja sitä kautta jätteiden määrän vähentämistä. Joutsenmerkin valintakriteerien pohjana on aina tuotteiden elinkaarianalyysi. Joutsenmerkin valintakriteerien soveltaminen Talousvarikon toimintoihin vaatetus- ja tekstiilimateriaalin elinkaaren jokaisessa vaiheessa antaa mahdollisuuden lisätä ekologista elinkaaren hallintaa Talousvarikon toiminnoissa. Ympäristönäkökohtien huomioiminen tuotekehityksessä ja hankinnoissa antaa mahdollisuuden tehdä tilauksia / sopimuksia yhteiskuntavastuullisilta yrityksiltä huomioiden valmistuksen yhdeksi osaksi hankinta ja logistiikka pääprosessia.

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Left ventricular hypertrophy (LVH) is due to pressure overload or mechanical stretch and is thought to be associated with remodeling of gap-junctions. We investigated whether the expression of connexin 43 (Cx43) is altered in humans in response to different degrees of LVH. The expression of Cx43 was analyzed by quantitative polymerase chain reaction, Western blot analysis and immunohistochemistry on left ventricular biopsies from patients undergoing aortic or mitral valve replacement. Three groups were analyzed: patients with aortic stenosis with severe LVH (n=9) versus only mild LVH (n=7), and patients with LVH caused by mitral regurgitation (n=5). Cx43 mRNA expression and protein expression were similar in the three groups studied. Furthermore, immunohistochemistry revealed no change in Cx43 distribution. We can conclude that when compared with mild LVH or with LVH due to volume overload, severe LVH due to chronic pressure overload is not accompanied by detectable changes of Cx43 expression or spatial distribution.

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El paisaje puede ser visto como la expresión territorial del metabolismo que cualquier sociedad mantiene con los sistemas naturales que la sustentan. Uno de los caminos para comprender cómo y por qué la intervención humana cambia la configuración del territorio consiste en analizar los flujos energéticos del intercambio metabólico de la economía con su entorno ambiental, y en identificar los impactos ecológicos que se imprimen en él. Este trabajo busca verificar, mediante la contabilidad del metabolismo social, y el empleo diacrónico de diversos índices desarrollados por la ecología del paisaje, que el enorme incremento de energía externa empleada por los sistemas agrarios tras la “revolución verde”, y la drástica reducción de su eficiencia, están estrechamente relacionados con los cambios de uso del suelo que han degradado considerablemente los tradicionales paisajes agrarios en mosaico del Mediterráneo. El recurso a flujos biofísicos externos, y el abandono del manejo integrado del territorio, han comportado una pérdida de la estructura funcional de la matriz territorial y de su conectividad ecológica. Los resultados obtenidos en cinco municipios de la comarca catalana del Vallès corroboran la estrecha relación existente durante los últimos 150 años entre la eficiencia energética y territorial, y el estado ecológico del paisaje.

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Diplomityössä kehitettiin Warkaus Works Oy:n tulistimien valmistuslinjan tuotantoa. Työn tavoitteena oli lyhentää läpimenoaika puoleen nykyisestä, kasvattaa tuotantokapasiteettiä, parantaa tuottavuutta ja toimitusvarmuutta. Työn teoriaosassa käsiteltiin erilaisia tuotannon kehittämiskeinoja, tuotannon analysointisystematiikkaa sekä automatisointiprojektin teoriaa. Työn kokeellisessa osassa selvitettiin tuotannon nykytila, jotta osattaisiin puuttua oikeisiin asioihin ja saataisiin vertailulähtökohta. Työssä selvitettiin tuotannon uudelleenvirtauttamisella saavutettavat hyödyt. Tuotannon kehittäminen painottui käsivaiheiden automatisointiin. Työssä selvitettiin eri automatisointi vaihtoehtoja. Työn tuloksena löydettiin tulistinputkien jatkohitsaukseen automatisointiratkaisu, jonka avulla käsinhitsattavien saumojen määrä rakenteessa parhaimmillaan puolittuu. Ratkaisun avulla läpimenoaikaa saadaan lyhennettyä ja tuotantokapasiteettiä nostettua ja tuottavuutta parannettua.

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Kaksifaasivirtauksen kuvaamiseen käytettävät mallit, ja menetelmät kaksifaasivirtauksen painehäviön määrittämiseksi kehittyvät yhä monimutkaisimmiksi. Höyrystinputkissa tapahtuvien painehäviöiden arvioinnin vaatiman laskennan suorittamiseksi tietokoneohjelman kehittäminen on välttämätöntä. Tässä työssä on kehitetty itsenäinen PC-ohjelma painehäviöiden arvioimiseksi pakotetulle konvektiovirtaukselle pystysuorissa höyrykattilan höyrystinputkissa. Veden ja vesihöyryn aineominaisuuksien laskentaan käytetään IAPWS-IF97 –yhtälökokoelmaa sekä muita tarvittavia IAPWS:n suosittelemia yhtälöitä. Höyrystinputkessa kulloinkin vallitsevan virtausmuodon määrittämiseen käytetään sovelluskelpoisia virtausmuotojen välisiä rajoja kuvaavia yhtälöitä. Ohjelmassa käytetään painehäviön määritykseen kirjallisuudessa julkaistuja yhtälöitä, virtausmuodosta riippuen, alijäähtyneelle virtaukselle, kupla-, tulppa- ja rengasvirtaukselle sekä tulistetun höyryn virtaukselle. Ohjelman laskemia painehäviöarvioita verrattiin kirjallisuudesta valittuihin mittaustuloksiin. Laskettujen painehäviöiden virhe vaihteli välillä –19.5 ja +23.9 %. Virheiden itseisarvojen keskiarvo oli 12.8 %.

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The construction and evaluation of an inexpensive flow photometer for clinical analysis, using a bicolour LED and a phototransistor adapted for tubular flow cell, are described. The instrument presents some new features such as: automatic zero, electronic calibration and peak-hold signal. When compared with a classical photometer, it is simpler and has the advantages of a flow analysis system: lower volumes of reagents and samples, lower levels of contamination, shorter time for analysis and lower analysis costs. The instrument was used in the determination of the constituents in blood samples. The results obtained agree with those obtained by a classical photometer and the precision was better.

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A flow system procedure for spectrophotometric determination of ascorbic acid in drugs based on [Fe3+(SCN-)n]+3-n complex decomposition by reduction is described. The flow network was constituted by a set of three-way solenoid valves, controlled by a microcomputer running a software wrote in QuickBasic 4.5 language. The feasibility of the procedure was ascertained by determining ascorbic acid in drug samples with mass ranging from 0.0018 up to 0.0180 g. The results showed an agreement of about 7% when compared with recommended method. Other profitable features such as a standard deviation of 1.5% (n = 7) and a throughput of 120 determinations per hour was also achieved.

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The construction of a tubular hydrogen ion-selective potentiometric electrode without inner reference solution, based on the tridodecylamine (TDDA) ionophore, and its evaluation in a flow system are described. TDDA was dissolved in 2-nitrophenyl octyl ether, dispersed in a PVC membrane and applied directly to a conducting support which consisted of an epoxy resin and graphite mixture. The electrode was designed with a tubular geometry to effort facilities to be coupled as part of a flow injection network. The main working characteristics such as response time, linear pH range, selectivity and life time were evaluated and compared with those obtained which a conventionally shaped electrode based on the same sensor. The electrode showed a slope of 51-52 mV dec-1 within a linear pH range from 4.0 up to 12.0.

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A simple flow cell for potentiometric detection is described. It was assembled by making use of two perspex pieces fixed together by means of four screws, and allow the connection of plane membrane conventional electrodes to flow system. Details about its construction are presented. The device performance was evaluated by making use of a cyanide ion-selective electrode. The relative standard deviation was about 0.5% with a detection limit of 8.0 x 10-6 mol CN- dm-3. Under experimental conditions, the linear range was 10-5 to10-2 mol dm-3.

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A new automated system for acid-base flow titrations is proposed. In the operation mode, several sample to titrant volumetric ratios are injected in an air segmented plug. Five three way solenoid valves and three acrilic junctions, assembled in a hidrodynamic injection system, were accountable for the monosegmented reagents plug formation. A turbulent flow reactor was used for a perfect mix of reagents in the plug. The detector system employed a glass combined electrode fitted in an acrilic holder. Titrations of hydrochloric, nitric and acetic acids, in several concentrations, were performed with standard sodium hidroxide, for evaluation of the efficiency of the system. The relative standard deviation of the determinations was about ±0,5% and each titration was carried out in 3-4 minutes. A Quick BASIC 4.5® program was developed for the titrator control.

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A on-line thermostatization system that use simples materials, for flow injection and continuous flow analysis is described. The proposed system showed good performance between 10 to 40ºC.

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The aim of this report is to classify analytical methods based on flowing media and to define (standardize) terminology. After the classification and a discussion of terms describing the systems and component parts, a section is devoted to terms describing the performance of flow systems. The list of terms included is restricted to the most relevant ones; especially "self-explanatory" terms are left out. It is emphasised that the usage of terms or expressions that do not adequately describe the processes or procedures involved should be strongly discouraged. Although belonging to the category of methods based on flowing media, chromatographic methods are not comprised in the present document. However, care has been taken that the present text is not in conflict with definitions in that domain. In documents in which flow methods are described, it should be clearly indicated how the sample and/or reagent is introduced and how the sample zone is transported. When introducing new techniques in the field, or variants of existing techniques, it is strongly recommended that descriptive terms rather than trivial or elaborate names are used.

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A simple and low cost flow cell is proposed for measurements by solid-phase spectrophotometry employing a conventional spectrophotometer. The flow cell geometry allows the employment of a large amount of the solid support without causing both excessive attenuation of the radiation beam and increasing of the back-pressure. The adaptation of the flow cell in the optical path of the spectrophotometer in order to increase the precision is discussed. The flow cell characteristics were demonstrated by measurements of Co(II), employing 1-(2-tiazolylazo)-2-naphthol (TAN) immobilized on C18 bonded silica as solid support. The apparent molar absorptivity and coefficient of variation were estimated as 1.86 x 10(5) L mol-1 cm-1 and 1.4 % (n=15). A sample throughput of 40 determinations per hour and a detection limit of 15 mug L-1 (99.7 % confidence level) were achieved.

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A spectrophotometric flow injection analysis (FIA) procedure employing natural urease enzyme source for the determination of urea in animal blood plasma was developed. Among leguminous plants used in the Brazilian agriculture, the Cajanus cajan specie was selected as urease source considering its efficiency and availability. A minicolumn was filled with leguminous fragments and coupled to the FIA manifold, where urea was on-line converted to ammonium ions and subsequently it was quantified by spectrophotometry. The system was employed to determine urea in animal plasma samples without any prior treatment. Accuracy was assessed by comparison results with those obtained employing the official procedure and no significant difference at 90 % confidence level was observed. Other profitable features such as an analytical throughput of 30 determinations per hour, a reagent consumption of 19.2 mg sodium salicylate, 0.5 mg sodium hipochloride and a relative standard deviation of 1.4 % (n= 12) were also obtained.

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Aquarium air pumps are proposed and evaluated as pneumatic liquid propulsion devices for flow injection and continuos flow analysis (FIA and CFA) systems. This kind of pump is widely available at a very low cost and it can sustain a pressure around of 4 psi (0.28 bar) indefinitely. By applying this air pressure onto a solution contained in a reservoir flask, it is possible to reach flow rates of up to 12.5 mL min-1 for circuits comprising reactors, made from 0.8 i.d. tubing with a length of 100 cm. The precise adjustment of flow rate below the maximum one can be made with a simplified needle valve or inserting in series a short length of capillary tube. The absence of flow pulsation is a definite advantage in comparison with peristaltic pumps, especially when amperometric detection is elected, as confirmed experimentally in FIA and CF applications.