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  • 1.
    Forsberg, Ulf
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Christofer
    Umeå University, Faculty of Science and Technology, Umeå Institute of Technology.
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    A high blood level in the air trap reduces microemboli during hemodialysis2012In: Artificial Organs, ISSN 0160-564X, E-ISSN 1525-1594, Vol. 36, no 6, p. 525-529Article in journal (Refereed)
    Abstract [en]

    Previous studies have demonstrated the presence of air microemboli in the dialysis circuit and in the venous circulation of the patients during hemodialysis. In vitro studies indicate that a high blood level in the venous air trap reduces the extent of microbubble formation. The purpose of this study was to examine whether air microbubbles can be detected in the patient's access and if so, whether the degree of microbubble formation can be altered by changing the blood level in the venous air trap. This was a randomized, double-blinded, interventional study of 20 chronic hemodialysis patients. The patients were assigned to hemodialysis with either an elevated or a low blood level in the air trap. The investigator and the patient were blinded to the settings. The numbers of microbubbles were measured at the site of the arteriovenous (AV) access for 2 min with the aid of an ultrasonic Doppler device. The blood level in the air trap was then altered to the opposite setting and a new measurement was carried out after an equilibration period of 30 min. Median (range) for the number of microbubbles measured with the high air trap level and the low air trap level in AV access was 2.5 (0-80) compared with 17.5 (0-77), respectively (P = 0.044). The degree of microbubble formation in hemodialysis patients with AV access was reduced significantly if the blood level in the air trap was kept high. The exposure of potentially harmful air microbubbles was thereby significantly reduced. This measure can be performed with no additional healthcare cost.

  • 2.
    Gustafsson, Tony
    Umeå University, Faculty of Science and Technology, Umeå Institute of Technology. Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Reservkraft och reservdrift i Messaure kraftstation2015Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    A major part of the hydropower plants in Sweden has been in operation for a long time. There have been large changes in how the operation of hydropower plants is managed. There used to be operating personnel on site at each power plant. Today's operating personnel patrol several power plants, and the control and operation is done from a control center. Nowadays the hydropower has gained a greater role as a balancing force. This leads to higher demands for hydropower plants. In order to achieve good safety and ensure that current guidelines are followed, many of the power plants need maintenance and/or reconstruction.

    The amount of water going through the turbine in a hydropower plant is adjusted to the annual average water flow. The instantaneous flow of water varies a lot during the year, and the water flow is at its lowest when the energy is most needed. Therefore, dams are used to store water and energy can be generated during the parts of the year when it is most needed. The dam should always be able to compensate for peak flows, even at loss of local power. To make this possible, backup power and emergency operation is needed. The guidelines for dam safety contain basic principles on how backup power and emergency operation should be designed depending on the type of dam and safety class. Every power plant is unique and needs to adapt these functions according to what is appropriate for the individual power plant.

    The owners of the dam are obliged to do regular self-controls. One way to do this is to perform a “comprehensive dam safety evaluation” (FDU). A dam that has shown weaknesses and deviations in the latest FDU report is the dam at Messaure. In 2013, a number of deviations from current guidelines of backup power and emergency operation were identified. This report investigates possible ways to meet current guidelines for these functions.

    The report investigates the different types of loads in Messaure power station, the size of the loads and whether they need to be connected to the backup power. At startup, different types of loads are affecting the diesel generator in the backup power in different ways. Currents have been measured and analyzed. With this in consideration, a number of suggestions on how to solve backup power and emergency operation challenges at the Messaure power station are presented.

    The different suggestions have different strengths, especially when taking economic aspects into account. The suggestion recommended in this report is the one that is the most redundant and follows current research and guidelines: a backup power system with UPS and battery packs for all three spillway gates. The UPS:s run asynchronous motors, standard products held in storages. In case of local force failure, the existing diesel generator is used for heating, lighting and maintenance charging of the battery packs to the UPS's. To create redundancy in the system the cables should be feeding the UPS:s separately, as far as possible.

    For emergency operation, a diesel generator that manages a direct start without excessive voltage drop is selected. To avoid failure in the spill way function, the engine's torque and power must not drop too much. The emergency operation diesel generator is installed on a trailer and - in case of emergency – is transported and connected to the spill way.

     

  • 3.
    Kohlström, Henrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Umeå Institute of Technology.
    Dosering av svavelgranulat i biobränsle och dess effekter på verkningsgraden och kolmonoxid för en biopanna2013Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Consistent environmental work is something that is highly prioritized among modern industries. A part of this project is to view the possibilities of further reducing the amount of emission from Smurfit Kappa’s bio boiler. Even though they are under the set emission demands, there is always room for improvement.My part in this project is to add elemental sulfur to biofuel. By doing this I hope to decrease the emission created by the bio boiler and at the same time increase efficiency of said boiler.Earlier studies have shown that the ratio sulfur/MJ fuel should be around 10-20mg S/MJ to be able to get results that show a 50% CO reduction.In my experiments we set a limit to 1,5-2,5mg S/MJ. My results show a CO reduction that’s between 16-60%. I have seen boiler efficiency ranging between -0.03% and as high as 2.5% but there are a few factors that give an error margin in my results. A fixed ratio for added sulfur and CO reduction and boiler efficiency could not be reached in this project.

  • 4.
    Nilsson, Lennart
    Umeå University, Faculty of Science and Technology, Umeå Institute of Technology.
    Implementering av CDIO i sex ingenjörsprogram2007In: Utsikter, insikter, avsikter: universitetspedagogisk konferens i Umeå 27 – 28 februari 2007 / [ed] Mohammad Fazlhashemi och Thomas Fritz, Uppsala, Sweden: Universitetspedagogiskt Centrum, Umeå universitet , 2007, p. 209-215Conference paper (Other academic)
    Abstract [sv]

    Sedan ett år tillbaka driver Umeå Tekniska Högskola Kuling-projektet där Kuling står för Kvalitet i Utbildning och Lärande för Ingenjörsutbildningarna vid Umeå universitet. Syftet med projektet är att omdana ingenjörsutbildningarna enligt CDIO-konceptet. En modell för omdaningen som vi då arbetar efter är:

    1. Acceptera CDIO syllabus som riktlinje för utbildningen och CDIO principer som hjälpmedel att nå målen

    2. Identifiera det nuvarande programmets styrkor och svagheter relativt CDIO syllabus.

    3. Utarbeta en strategi för programmets utveckling och förankradenna strategi i lärarlaget, bland studenterna, på institutionen osv.

    4. Förankra CDIO lärandemål i kursplaner, utbildningsplan och examensbeskrivning.

    5. Skapa processer som garanterar att omdaningen lever vidare under ständig utveckling.

    I denna presentation belyses arbetet under några av dessa punkter och några viktiga inslag i utbildningen beskrivs utförligare.

  • 5.
    Puga, Ulises
    Umeå University, Faculty of Science and Technology, Umeå Institute of Technology.
    Transportrack: Förpackning av gripklor för transport2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Cranab AB specielliserar sig på att bygga kranar och gripklor till skogsmakiner, denna rapport kommer enbart att handla om hur författaren har gått till väga för att hjälpa Cranab AB att komma med idéer och koncept för transportrack som ska transportera gripklorna som skärs ut och svetsas ihop på cranab 2 och sedan skickas över till cranab 1 för vidare bearbetning, målning och slutligen montering.

    Just nu så skickas färdiga klor av olika storlekar från cranab 2 till cranab 1 på standard SJ-pallar gjord av trä. Syftet med detta arbete är då att komma med idéer och koncept på emballage så att man kan skicka dessa gripklor i färdiga set, bestående av; innerklo, ytterklo och vagga i ett och samma ”paket”, detta för att bli av med träpallarna och effektivisera arbetet, i och med att Cranab vill kunna hantera beställningar som är både personliga och flexibla.

    För att arbeta med problemställningen så har Solid Works tagits till som hjälpmedel och även samtal med konstruktörerna samt en förstudie på Cranab AB logistic.

  • 6.
    Ulf, Forsberg
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Stegmayr, Christofer
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Umeå University, Faculty of Science and Technology, Umeå Institute of Technology.
    Jonsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Nilsson, Bo
    Nilsson Ekdahl, Kristina
    Stegmayr, Bernd
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    A high blood level in the venous chamber and a wet-stored dialyzer help to reduce exposure for microemboli during hemodialysis2013In: Hemodialysis International, ISSN 1492-7535, E-ISSN 1542-4758, Vol. 17, no 4, p. 612-617Article in journal (Refereed)
    Abstract [en]

    During hemodialysis (HD), microemboli develop in the blood circuit of the apparatus. These microemboli can pass through the venous chamber and enter into the patient's circulation. The aim of this study was to investigate whether it is possible to reduce the risk for exposure of microemboli by altering of the treatment mode. Twenty patients on chronic HD were randomized to a prospective cross-over study of three modes of HD: (a) a dry-stored dialyzer (F8HPS, Fresenius, steam sterilized) with a low blood level in the venous chamber (DL), (b) the same dialyzer as above, but with a high level in the venous chamber (DH), and (c) a wet-stored dialyzer (Rexeed, Asahi Kasei Medical, gamma sterilized) with a high blood level (WH). Microemboli measurements were obtained in a continuous fashion during 180 minutes of HD for all settings. A greater number of microemboli were detected during dialysis with the setting DL vs. WH (odds ratio [OR] 4.07, 95% confidence interval [CI] 4.03–4.11, P < 0.0001) and DH vs. WH (OR 1.18, 95% CI 1.17–1.19, P < 0.0001) and less for DH vs. DL (OR 0.290, 95% CI 0.288–0.293, P < 0.0001). These data indicate that emboli exposure was least when using WH, greater with DH, and most with DL. This study shows that using a high blood level in the venous chamber and wet-stored dialyzers may reduce the number of microemboli.

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