50 research outputs found

    Middle East - North Africa and the millennium development goals : implications for German development cooperation

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              Closed-loop controlled combustion is a promising technique to improve the overall performance of internal combustion engines and Diesel engines in particular. In order for this technique to be implemented some form of feedback from the combustion process is required. The feedback signal is processed and from it combustionrelated parameters are computed. These parameters are then fed to a control process which drives a series of outputs (e.g. injection timing in Diesel engines) to control their values. This paper’s focus lies on the processing and computation that is needed on the feedback signal before this is ready to be fed to the control process as well as on the electronics necessary to support it. A number of feedback alternatives are briefly discussed and for one of them, the in-cylinder pressure sensor, the CA50 (crank angle in which the integrated heat release curve reaches its 50% value) and the IMEP (Indicated Mean Effective Pressure) are identified as two potential control variables. The hardware architecture of a system capable of calculating both of them on-line is proposed and necessary feasibility size and speed considerations are made by implementing critical blocks in VHDL targeting a flash-based Actel ProASIC3 automotive-grade FPGA

    71. Grafting of ovarian tissue in a non-human primate model

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    Confirmed dioestrus in pseudopregnant mice using vaginal exfoliative cytology improves embryo transfer implantation rate

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    Embryo transfer is a commonly performed surgical technique. In mice, protocols typically specify pairing recipient females with vasectomized males to induce a receptive uterine environment for embryo implantation. However, this induced receptive state is not always maintained until implantation occurs. The use of a well-characterized correlation between oestrous state and exfoliative vaginal cytology was therefore evaluated to assess uterine receptivity immediately before embryo transfer. Eight- to 12-week-old virgin female CD1 mice (n = 22) were paired overnight with vasectomized males and successfully mated, indicated by the presence of a vaginal plug. These dams underwent embryo transfer 3 days later with embryos obtained from superovulated 4-week-old F1 (C57BL/6 × CBA) females. Non-invasive vaginal lavage was conducted immediately before transfer. Dams were killed 6 days after transfer and the uterus collected for histological analysis. Embryo implantation rate in mice was 96% when cytological analysis of the lavage samples signified dioestrus (n = 6), whereas the implantation rate was <15% (n = 16) when cytology signified other stages of oestrous. This simple, quick, non-invasive measure of receptivity was accurate and easily adopted and, when applied prospectively, will avoid unnecessary surgery and subsequent culling of non-suitable recipients, while maximizing the implantation potential of each recipient female

    Confirmed dioestrus in pseudopregnant mice using vaginal exfoliative cytology improves embryo transfer implantation rate

    No full text
    Embryo transfer is a commonly performed surgical technique. In mice, protocols typically specify pairing recipient females with vasectomized males to induce a receptive uterine environment for embryo implantation. However, this induced receptive state is not always maintained until implantation occurs. The use of a well-characterized correlation between oestrous state and exfoliative vaginal cytology was therefore evaluated to assess uterine receptivity immediately before embryo transfer. Eight- to 12-week-old virgin female CD1 mice (n = 22) were paired overnight with vasectomized males and successfully mated, indicated by the presence of a vaginal plug. These dams underwent embryo transfer 3 days later with embryos obtained from superovulated 4-week-old F1 (C57BL/6 × CBA) females. Non-invasive vaginal lavage was conducted immediately before transfer. Dams were killed 6 days after transfer and the uterus collected for histological analysis. Embryo implantation rate in mice was 96% when cytological analysis of the lavage samples signified dioestrus (n = 6), whereas the implantation rate was <15% (n = 16) when cytology signified other stages of oestrous. This simple, quick, non-invasive measure of receptivity was accurate and easily adopted and, when applied prospectively, will avoid unnecessary surgery and subsequent culling of non-suitable recipients, while maximizing the implantation potential of each recipient female

    Nitrogen degradation of the limestone-urea mixtures in the rumen of goats

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    This experiment was aimed to study the degradation kinetics of limestone-urea mixtures in the goats rumen using the nylon bag technique. Samples of limestone were obtained from two limestone mountains, Pamotan Subdistrict of Central Java Province and Wonosari Subdistrict of Yogyakarta Province. The mixtures were created by combining urea at levels 25, 50, 75and 100%; respectively with two limestones on the basis of their Ca contents: L0U100, LP25U75, LP50U50; LP75U25, LW25U75; LW50U50; and LW75U25. The soluble fraction, potentially degradable fraction, the degradation rate of potentially degradable fraction, and effective degradation of respective dry matter (DM) and nitrogen (N) ruminal degradation kinetics were measured in each mixture. The mixture of LP75U25 had lowest effective and degradation rate of potentially degradable fraction (P<0.05) respectively for DM and N compared with those of other mixtures. In conclusion, the limestone-urea mixture of LP75U25 could be suggested as a dietary supplement of ruminal N slow release

    Over a century of small hydropower projects in Indonesia: a historical review

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    Abstract Background Hydropower is a mature energy technology and one that could play a more important role in providing clean and reliable energy. In small-scale contexts, hydropower is useful for providing electricity access, balancing intermittent resources, and as a potential source of energy storage. This paper provides a comprehensive exploration of the development of the small hydropower (SHP) sector in Indonesia, the world’s fourth most populous country. Methods Two research methods were employed: secondary data analysis through a desk review of relevant literature and primary data collection through site visits and expert and stakeholder interviews. Two case studies of micro-hydro applications in community-based rural electrification were analyzed. The paper explores how SHP projects were initiated, lessons learned, and policy recommendations of relevance to further development of distributed small-scale renewable energy in Indonesia. Results The sector commenced during the Dutch Era and now centers on both community-based rural electrification projects and commercial schemes under the independent power producer (IPP) approach. Since the late 1980s, initiatives to implement SHP for rural electrification have flourished through various programs. Key regulatory, economic, and technical barriers include inconsistent and unclear supporting regulations, especially regarding electricity prices; artificially low retail electricity prices; capital and borrowing constraints; advantages provided to fossil fuels; limited technical experience and capabilities of project developers and project sponsors; risks from floods, earthquakes, and landslides; constraints on supporting infrastructure; and limited grid links. The most successful and sustainable SHP projects are ones that provide local economic benefits and for which local communities are empowered with ownership and have responsibility for maintenance. Conclusions SHP will remain small from a macro perspective but could still play a key role in further improving energy access and equity in remote areas. Key initiatives to facilitate this development could include local-level capacity building and project participation and the adequate pricing of negative externalities from fossil fuel projects. Indonesia’s long experience with SHP carries lessons for other developing countries

    Pemodelan Numerik Run Up dan Overtopping Struktur Seawall Buis Beton

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    Bangunan pelindung pantai banyak macam dan jenisnya, namun memiliki tujuan yaitu untuk melindungi kawasan pantai dari gelombang. Dikarenakan gelombang akan bersifat katastropik apabila terlalu besar. Penelitian terhadap bangunan pelindung pantai banyak dilakukan pada analisa transmisi, refleksi, limpasan dan rayapan. Pemilihan buis beton untuk penelitian dikarenakan masyarakat pesisir banyak menggunakannya sebagai bangunan pantai. Karena buis beton mudah dijumpai, murah dan mudah dalam pengaplikasiannya. Namun belum ada analisis secara ilmiah mengenai buis beton sebagai bangunan pantai. Pada penelitian ini akan dilakukan analisis run up dan overtopping dengan berdasarkan gelombang regular uji fisik buis beton Balai Pantai menggunakan pemodelan CFD Flow-3D. Penelitian ini memvariasikan tinggi freeboard buis beton yaitu 0,05 m dan 0,2 m, variasi kemiringan untuk masing-masing freeboard 45°, 26,56° dan 18,26° dengan mengubah perletakan buis beton secara vertikal. Untuk hasil variasi, model dengan freeboard 0,05 memiliki hasil run up sama 0,05 m atau tinggi maksimal struktur, sedangkan nilai run up pada struktur dengan freeboard 0,2 hasil run up terendah yaitu pada model B3.60 dengan kemiringan 18,26° sebesar 0,17 m. Untuk overtopping relatif struktur dengan freeboard 0,2 lebih kecil dari pada struktur dengan freeboard 0,05. Hasil dari run up dan overtopping dilakukan perbandingan dengan pengaruh kemiringan, tinggi freeboard dan irribaren parameter dari penelitian lain, namun perbandingan dilakukan hanya untuk melihat trend persebarannya karena struktur yang diteliti berbeda dengan yang dilakukan oleh peneliti lain
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