932 resultados para reactor operation
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The use of a mesofluidic flow reactor is described for performing Curtius rearrangement reactions of carboxylic acids in the presence of diphenylphosphoryl azide and trapping of the intermediate isocyanates with various nucleophiles.
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A general flow process for the multi-step assembly of peptides has been developed and this procedure has been used to successfully construct a series of Boc, Cbz and Fmoc N-protected dipeptides in excellent yields and purities, including an extension of the method to enable the preparation of a tripeptide derivative.
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Report for the DETR on the operation of the Crichel Down Rules (July 2000). The Crichel Down Rules are non-statutory rules relating to the offer back to the previous owners of surplus government land that was acquired from the previous owners by, or under the threat of, compulsory purchase.
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This study aimed at evaluating the effect of increasing organic loading rates and of enzyme pretreatment on the stability and efficiency of a hybrid upflow anaerobic sludge blanket reactor (UASBh) treating dairy effluent. The UASBh was submitted to the following average organic loading rates (OLR) 0.98 Kg.m(-3).d(-1), 4.58 Kg.m(-3).d(-1), 8.89 Kg.m(-3).d(-1) and 15.73 Kg.m(-3).d(-1), and with the higher value, the reactor was fed with effluent with and without an enzymatic pretreatment to hydrolyze fats. The hydraulic detention time was 24 h, and the temperature was 30 +/- 2 degrees C. The reactor was equipped with a superior foam bed and showed good efficiency and stability until an OLR of 8.89 Kg.m(-3).d(-1). The foam bed was efficient for solid retention and residual volatile acid concentration consumption. The enzymatic pretreatment did not contribute to the process stability, propitiating loss in both biomass and system efficiency. Specific methanogenic activity tests indicated the presence of inhibition after the sludge had been submitted to the pretreated effluent It was concluded that continuous exposure to the hydrolysis products or to the enzyme caused a dramatic drop in the efficiency and stability of the process, and the single exposure of the biomass to this condition did not inhibit methane formation. (C) 2011 Elsevier B.V. All rights reserved.
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1,3-beta-Glucan depolymerizing enzymes have considerable biotechnological applications including biofuel production, feedstock-chemicals and pharmaceuticals. Here we describe a comprehensive functional characterization and low-resolution structure of a hyperthermophilic laminarinase from Thermotoga petrophila (TpLam). We determine TpLam enzymatic mode of operation, which specifically cleaves internal beta-1,3-glucosidic bonds. The enzyme most frequently attacks the bond between the 3rd and 4th residue from the non-reducing end, producing glucose, laminaribiose and laminaritriose as major products. Far-UV circular dichroism demonstrates that TpLam is formed mainly by beta structural elements, and the secondary structure is maintained after incubation at 90 degrees C. The structure resolved by small angle X-ray scattering, reveals a multi-domain structural architecture of a V-shape envelope with a catalytic domain flanked by two carbohydrate-binding modules. Crown Copyright (C) 2011 Published by Elsevier Inc. All rights reserved.
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The photocatalytic degradation of phenol in aqueous suspensions of TiO(2) under different salt concentrations in an annular reactor has been investigated. In all cases, complete removal of phenol and mineralization degrees above 90% were achieved. The reactor operational parameters were optimized and its hydrodynamics characterized in order to couple mass balance equations with kinetic ones. The photodegradation of the organics followed a Langmuir-Hinshelwood-Hougen- Watson lumped kinetics. From GC/MS analyses, several intermediates formed during oxidation have been identified. The main ones were catechol, hydroquinone, and 3-phenyl-2-propenal, in this order. The formation of negligible concentrations of 4-chlorophenol was observed only in high salinity medium. Acute toxicity was determined by using Artemia sp. as the test organism, which indicated that intermediate products were all less toxic than phenol and a significant abatement of the overall toxicity was accomplished, regardless of the salt concentration.
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Syftet med denna systematiska litteraturstudie var att beskriva barnets emotionella omvårdnadsbehov i den förberedande fasen inför operation. Vidare var syftet att beskriva sjuksköterskans metoder vid förberedelse av barnet för att skapa trygghet.Artikelsökningarna genomfördes på databaserna Elin@dalarna och Cinahl med sökorden operation, preoperative, children, preparation, information, nursing, care och nurse. Sökorden fanns i artiklarnas abstract. Artiklarna var vetenskapliga, skrivna på engelska och publicerade år 1997 till 2007. Endast primärartiklar söktes och deras relevans bedömdes efter titel och abstract. I resultatet återfanns 20 artiklar som kunde besvara syftet och frågeställningarna i studien. Studien visade att i den förberedande omvårdnaden behövde barnet känna trygghet och tillit till sjuksköterskan. Barnet förväntade sig ärlighet och behövde förklaringar. Sjuksköterskan skulle bygga förtroende hos barnet. Det fanns många olika metoder för sjuksköterskan att förbereda barn inför operation. Dessa kunde vara att barnet fick komma på studiebesök för att se avdelningen och träffa sjuksköterskor, anestesi personal och läkare. Barnet fick information via broschyrer, böcker eller videofilmer angående preoperativa förberedelser. Operationer på vuxenavdelningar krävde att de förberedande metoder som fanns tillgängliga kombinerades för att ett bra resultat skulle uppnås. Förberedelserna och informationen anpassades till barnet. Sjuksköterskan kunde med fördel involvera föräldrarna i omvårdnaden av barnet. Föräldrarna kunde ge information om barnet och minska barnets oro.
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Syftet med denna litteraturstudie var att undersöka vilka emotionella omvårdnadsbehov patienterna hade innan operation och hur sjuksköterskan på bästa sätt kunde lindra dem. Metoden var en litteraturstudie baserad på vetenskapliga artiklar med dels en kvalitativ ansats (n= 5) och dels en kvantitativ (n= 10). Artikelsökningarna gjordes via sökmotorn ELIN och databaserna CINAHL och PubMED. Artiklarna var etiskt godkända samt publicerade mellan 2000-2010 och skrivna på engelska. De granskades med hjälp av granskningsmallar. Resultaten i studien visade att de emotionella behov som fanns var att lindra rädsla och känslan av övergivenhet. Resultaten visade att sjuksköterskan, kunde lindra dessa emotionella behov genom information, ett gott bemötande, att låta patienterna lyssna på musik, se på film eller video samt ge essentiella oljor.
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Syfte: Syftet var att beskriva hur sjukvårdspersonal kan hjälpa vuxna patienter att sluta röka, en kortare eller längre tid, inför en elektiv operation.Metod: Studien genomfördes som en litteraturöversikt. Genom sökning i databaserna Pubmed och Cinahl erhölls 10 vetenskapliga artiklar. Sökningar genomfördes med både MeSH-termer och fritextsökning. Artiklarna kvalitetsgranskades, analyserades och samanställdes. Resultat: Metoder som kan användas för att hjälpa patienter att sluta röka är olika former av rådgivning och utbildning: hälsoutbildning, program för livsstilsförändringar, sluta-röka-linje. Att erbjuda rådgivning och stöd i kombination nikotinersättningspreparat är fungerande metoder: motiverande samtal och nikotinersättning, regelbunden rådgivning och nikotinersättning, rökavvänjning med hjälp av interaktivt dataprogram, information och hjälp med planering, nikotinersättning och uppmuntrande telefonsamtal. Effekten av nikotinplåster, läkemedel och akupunktstimulering som ensamma metoder var begränsad. Slutsatser: Olika former av rådgivning eller utbildning kan användas när patienter behöver sluta röka inför en elektiv operation. Metoder som kombinerar nikotinersättning och rådgivning eller stöd var mest effektiva. Använder sig sjukvårdspersonal av detta kan lidande minskas, undvika förlängd vårdtid och pengar sparas.
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Increasing costs and competitive business strategies are pushing sawmill enterprises to make an effort for optimization of their process management. Organizational decisions mainly concentrate on performance and reduction of operational costs in order to maintain profit margins. Although many efforts have been made, effective utilization of resources, optimal planning and maximum productivity in sawmill are still challenging to sawmill industries. Many researchers proposed the simulation models in combination with optimization techniques to address problems of integrated logistics optimization. The combination of simulation and optimization technique identifies the optimal strategy by simulating all complex behaviours of the system under consideration including objectives and constraints. During the past decade, an enormous number of studies were conducted to simulate operational inefficiencies in order to find optimal solutions. This paper gives a review on recent developments and challenges associated with simulation and optimization techniques. It was believed that the review would provide a perfect ground to the authors in pursuing further work in optimizing sawmill yard operations.
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Syftet med studien var att beskriva patientens upplevelser efter en gastric bypass operation. En empirisk studie med kvalitativ ansats genomfördes, där intervjuer skedde med sex personer som genomfört en gastric bypass operation. Data analyserades genom kvalitativ innehållsanalys. Under intervjuerna framkom att informanterna upplevde att operationen inte hade någon negativ inverkan på deras vardagliga liv. De upplevde en ökad livskvalitet och förbättrad hälsa som lett till ett mer fysiskt aktivt liv. Viktnedgången tillsammans med omgivningens positiva reaktioner på den nya kroppen hade stärkt deras självförtroende. Den största förändringen informanterna upplevde i det vardagliga livet var deras förändrade matvanor. De beskrev att maten var i fokus och att de planerade sin vardag efter måltiderna. De följder som framkom upplevdes inte som något stort problem, utan viktminskningen och de positiva hälsoupplevelserna dominerade. Informanterna kände sig välinformerade och hade realistiska förväntningar på operationen, samt var förberedda på de konsekvenser som kunde uppstå. Studien visar att den specialiserade vården på överviktskliniker kan bidra till att underlätta tiden efter operationen för patienten. Det framkom att informanterna upplevde en kunskapsbrist om gastric bypass operationer bland sjukvårdspersonal, inom primärvård och slutenvård. För att patienten ska känna trygghet och förtroende är det därför viktigt att öka kunskapen om överviktsoperationer bland hälso- och sjukvårdspersonal.
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This report contains a suggestion for a simple monitoring and evaluation guideline for PV-diesel hybrid systems. It offers system users a way to better understand if their system is operated in a way that will make it last for a long time. It also gives suggestions on how to act if there are signs of unfavourable use or failure. The application of the guide requires little technical equipment, but daily manual measurements. For the most part, it can be managed by pen and paper, by people with no earlier experience of power systems.The guide is structured and expressed in a way that targets PV-diesel hybrid system users with no, or limited, earlier experience of power engineering. It is less detailed in terms of motivations for certain choices and limitations, but rich in details concerning calculations, evaluation procedures and maintenance routines. A more scientific description of the guide can be found in a related journal article.
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Emissions from residential combustion appliances vary significantly depending on the firing behaviours and combustion conditions, in addition to combustion technologies and fuel quality. Although wood pellet combustion in residential heating boilers is efficient, the combustion conditions during start-up and stop phases are not optimal and produce significantly high emissions such as carbon monoxide and hydrocarbon from incomplete combustion. The emissions from the start-up and stop phases of the pellet boilers are not fully taken into account in test methods for ecolabels which primarily focus on emissions during operation on full load and part load. The objective of the thesis is to investigate the emission characteristics during realistic operation of residential wood pellet boilers in order to identify when the major part of the annual emissions occur. Emissions from four residential wood pellet boilers were measured and characterized for three operating phases (start-up, steady and stop). Emissions from realistic operation of combined solar and wood pellet heating systems was continuously measured to investigate the influence of start-up and stop phases on total annual emissions. Measured emission data from the pellet devices were used to build an emission model to predict the annual emission factors from the dynamic operation of the heating system using the simulation software TRNSYS. Start-up emissions are found to vary with ignition type, supply of air and fuel, and time to complete the phase. Stop emissions are influenced by fan operation characteristics and the cleaning routine. Start-up and stop phases under realistic operation conditions contribute 80 – 95% of annual carbon monoxide (CO) emission, 60 – 90% total hydrocarbon (TOC), 10 – 20% of nitrogen oxides (NO), and 30 – 40% particles emissions. Annual emission factors from realistic operation of tested residential heating system with a top fed wood pelt boiler can be between 190 and 400 mg/MJ for the CO emissions, between 60 and 95 mg/MJ for the NO, between 6 and 25 mg/MJ for the TOC, between 30 and 116 mg/MJ for the particulate matter and between 2x10-13 /MJ and 4x10-13 /MJ for the number of particles. If the boiler has the cleaning sequence with compressed air such as in boiler B2, annual CO emission factor can be up to 550 mg/MJ. Average CO, TOC and particles emissions under realistic annual condition were greater than the limits values of two eco labels. These results highlight the importance of start-up and stop phases in annual emission factors (especially CO and TOC). Since a large or dominating part of the annual emissions in real operation arise from the start-up and stop sequences, test methods required by the ecolabels should take these emissions into account. In this way it will encourage the boiler manufacturers to minimize annual emissions. The annual emissions of residential pellet heating system can be reduced by optimizing the number of start-ups of the pellet boiler. It is possible to reduce up to 85% of the number of start-ups by optimizing the system design and its controller such as switching of the boiler pump after it stops, using two temperature sensors for boiler ON/OFF control, optimizing of the positions of the connections to the storage tank, increasing the mixing valve temperature in the boiler circuit and decreasing the pump flow rate. For 85 % reduction of start-ups, 75 % of CO and TOC emission factors were reduced while 13% increase in NO and 15 % increase in particle emissions was observed.