Open Issues in Control ofAutomotive R744 Air-ConditioningSystems

In this thesis, one of the current control algorithms for the R744 cycle, which tries tooptimize the performance of the system by two SISO control loops, is compared to acost-effective system with just one actuator. The operation of a key component of thissystem, a two stage orifice expansion valve is examined in a range of typical climateconditions. One alternative control loop for this system, which has been proposed byBehr group, is also scrutinized.The simulation results affirm the preference of using two control-loops instead of oneloop, but refute advantages of the Behr alternate control approach against one-loopcontrol. As far as the economic considerations of the A/C unit are concerned, usinga two-stage orifice expansion valve is desired by the automotive industry, thus basedon the experiment results, an improved logic for control of this system is proposed.In the second part, it is investigated whether the one-actuator control approach isapplicable to a system consisting of two parallel evaporators to allow passengers tocontrol different climate zones. The simulation results show that in the case of usinga two-stage orifice valve for the front evaporator and a fixed expansion valve forthe rear one, a proper distribution of the cooling power between the front and rearcompartment is possible for a broad range of climate conditions.

Kvinnors upplevelse av planerad hemförlossning i Skandinavien : Women´s experience of planned home birth in the Scandinavian countries

Background: In Sweden and Norway planned home birth is not included in the health care system. In Denmark women with expected low risk birth have the right to choose home birth. Registrations of home births in the Nordic countries are not completed and women’s experiences of planned home birth in Scandinavian context are not earlier described.Objective: The aim of this study was to describe women’s experiences of planned home birth in the Scandinavian countries.Design: Inductive content analysis. Fifty-three Scandinavian women who have experienced planned home birth have replied an open question in a questionnaire. Findings: In the analysis five categories and twelve subcategories emerged. The categories were, to feel secure, experiences of support, being in control, harmony and insecurity. The women felt secure and calm in their own homes. They felt being in control, secure, support and trust in the midwife, relatives and the own body. What worried the women most in presence of the delivery was that the midwife should not be present. Keywords: Home birth, experiences, women.