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.

Film som kommunikation : En studie av gymnasieungdomars filmarbete

The starting point for this work was a discussion between my supervisor and myself during my teaching training. The discussion concerned the appropriateness of allowing students make films with sexual content. Film gives young people the opportunity to express their feelings and broaden their views. If the film then disseminates to unknown people via in-ternet, which it most likely will do, maybe it is no longer so positive. The aim of this study is to shed light on various aspects of identity and ethics that are important to keep in mind when young people in school make films. These aspects are to avoid making young people vulnerable to abuse and improper influence. One aim is also to highlight the advantages of making films in school. The study is inspired by hermeneutic interpretive and based on qualitative interviews. The informants are four students at the age of 18-19 at two different schools in one municipality in Sweden.The results of the study show that it is important for the informants that the films are pro-duced in an aesthetically good way so that it appeals to the audience. Two of the infor-mants have a specific audience and make more conscious choices, so that the audience will understand what is said. The study shows that the more a filmmaker considers the audi-ence, the more consciously he or she uses film as communication. To get positive feedback is important, but it is mostly friends of the filmmakers that actually comment. To get nega-tive comments is regarded as a disadvantage when placing material on the internet. Howev-er, none of the informants in the study have received negative comments on what has been posted. The opinions about what the informants believe is inappropriate to post on inter-net or to make films about regards sexuality and violations. Earlier studies show that mate-rial can, because it is interesting to other people, become widespread. For this reason it is important for teachers to have conversations with students about their preferences and opinions on various issues. Adults need to interfere in the young people's world, while be-ing open to their opinions. Then the young people's value system will be built up and give them a safe tool that helps them to avoid improper influence.

Effectiveness of artemether-lumefantrine provided by community health workers in under-five children with uncomplicated malaria in rural Tanzania : an open label prospective study

Background: Home-management of malaria (HMM) strategy improves early access of anti-malarial medicines to high-risk groups in remote areas of sub-Saharan Africa. However, limited data are available on the effectiveness of using artemisinin-based combination therapy (ACT) within the HMM strategy. The aim of this study was to assess the effectiveness of artemether-lumefantrine (AL), presently the most favoured ACT in Africa, in under-five children with uncomplicated Plasmodium falciparum malaria in Tanzania, when provided by community health workers (CHWs) and administered unsupervised by parents or guardians at home. Methods: An open label, single arm prospective study was conducted in two rural villages with high malaria transmission in Kibaha District, Tanzania. Children presenting to CHWs with uncomplicated fever and a positive rapid malaria diagnostic test (RDT) were provisionally enrolled and provided AL for unsupervised treatment at home. Patients with microscopy confirmed P. falciparum parasitaemia were definitely enrolled and reviewed weekly by the CHWs during 42 days. Primary outcome measure was PCR corrected parasitological cure rate by day 42, as estimated by Kaplan-Meier survival analysis. This trial is registered with ClinicalTrials.gov, number NCT00454961. Results: A total of 244 febrile children were enrolled between March-August 2007. Two patients were lost to follow up on day 14, and one patient withdrew consent on day 21. Some 141/241 (58.5%) patients had recurrent infection during follow-up, of whom 14 had recrudescence. The PCR corrected cure rate by day 42 was 93.0% (95% CI 88.3%-95.9%). The median lumefantrine concentration was statistically significantly lower in patients with recrudescence (97 ng/mL [IQR 0-234]; n = 10) compared with reinfections (205 ng/mL [114-390]; n = 92), or no parasite reappearance (217 [121-374] ng/mL; n = 70; p <= 0.046). Conclusions: Provision of AL by CHWs for unsupervised malaria treatment at home was highly effective, which provides evidence base for scaling-up implementation of HMM with AL in Tanzania.