Study of Staebler-Wronsky degradation effect in a Si:H based P-I-N solar cells

The objective of this study is to improve the stability and efficiency of thin solar cells with emphasis on a-Si:H devices. The research project was broken down into three main phases. The first involves designing and building a UHV glow discharge system; the second involves making good quality films and eventually efficient cells; the final phase will be analytical

Hypersonic Research Vehicle (HRV) real-time flight test support feasibility and requirements study. Part 2: Remote computation support for flight systems functions

The requirements are assessed for the use of remote computation to support HRV flight testing. First, remote computational requirements were developed to support functions that will eventually be performed onboard operational vehicles of this type. These functions which either cannot be performed onboard in the time frame of initial HRV flight test programs because the technology of airborne computers will not be sufficiently advanced to support the computational loads required, or it is not desirable to perform the functions onboard in the flight test program for other reasons. Second, remote computational support either required or highly desirable to conduct flight testing itself was addressed. The use is proposed of an Automated Flight Management System which is described in conceptual detail. Third, autonomous operations is discussed and finally, unmanned operations

Heat transport and flow structure in rotating Rayleigh-B\'enard convection

Here we summarize the results from our direct numerical simulations (DNS) and experimental measurements on rotating Rayleigh-B\'enard (RB) convection. Our experiments and simulations are performed in cylindrical samples with an aspect ratio \Gamma varying from 1/2 to 2. Here \Gamma=D/L, where D and L are the diameter and height of the sample, respectively. When the rotation rate is increased, while a fixed temperature difference between the hot bottom and cold top plate is maintained, a sharp increase in the heat transfer is observed before the heat transfer drops drastically at stronger rotation rates. Here we focus on the question of how the heat transfer enhancement with respect to the non-rotating case depends on the Rayleigh number Ra, the Prandtl number Pr, and the rotation rate, indicated by the Rossby number Ro. Special attention will be given to the influence of the aspect ratio on the rotation rate that is required to get heat transport enhancement. In addition, we will discuss the relation between the heat transfer and the large scale flow structures that are formed in the different regimes of rotating RB convection and how the different regimes can be identified in experiments and simulations.Comment: 12 pages, 10 figure

Towards an optical potential for rare-earths through coupled channels

The coupled-channel theory is a natural way of treating nonelastic channels, in particular those arising from collective excitations, defined by nuclear deformations. Proper treatment of such excitations is often essential to the accurate description of reaction experimental data. Previous works have applied different models to specific nuclei with the purpose of determining angular-integrated cross sections. In this work, we present an extensive study of the effects of collective couplings and nuclear deformations on integrated cross sections as well as on angular distributions in a consistent manner for neutron-induced reactions on nuclei in the rare-earth region. This specific subset of the nuclide chart was chosen precisely because of a clear static deformation pattern. We analyze the convergence of the coupled-channel calculations regarding the number of states being explicitly coupled. Inspired by the work done by Dietrich \emph{et al.}, a model for deforming the spherical Koning-Delaroche optical potential as function of quadrupole and hexadecupole deformations is also proposed. We demonstrate that the obtained results of calculations for total, elastic and inelastic cross sections, as well as elastic and inelastic angular distributions correspond to a remarkably good agreement with experimental data for scattering energies above around a few MeV.Comment: 7 pages, 6 figures. Submitted to the proceedings of the XXXVI Reuni\~ao de Trabalho de F\'{\i}sica Nuclear no Brasil (XXXVI Brazilian Workshop on Nuclear Physics), held in Maresias, S\~ao Paulo, Brazil in September 2013, which should be published on AIP Conference Proceeding Series. arXiv admin note: substantial text overlap with arXiv:1311.1115, arXiv:1311.042

Pengaruh Jarak Antara Elemen Batang Tekan Ganda Terhadap Kuat Tekan

Kayu sering digunakan sebagai batang tekan pada kuda-kuda dan kolom. Untuk mendukung bebanbesar dibutuhkan dimensi batang tekan tunggal cukup besar. Batang tekan tunggal dapat digantidengan batang tekan ganda yang terdiri dari dua atau lebih elemen batang yang digabung menjadisatu kesatuan. Jarak antara elemen mengakibatkan bertambah besarnya momen inersia terhadapsumbu bebas bahan yang berada diantara kedua tampang elemen tersebut. Secara teoritis semakinjauh jarak antara akan meningkatkan daya dukung, tetapi semakin tidak terjamin kerja sama antaraelemen-elemen sebagai satu kesatuan. Berdasarkan PKKI 1961 besarnya jarak antara 2 kalitebal elemen batang tekan. Berdasarkan uraian tersebut perlu dilakukan penelitian tentangpengaruh jarak antara elemen batang tekan ganda terhadap kuat tekan. Penelitian ini menggunakankayu Keruing dengan dimensi 2 x 3/10 panjang 2 m. Jarak antara elemen batang tekan ganda yangdigunakan adalah 0, 1.5, 3, 4.5 dan 6 cm. Jumlah benda uji setiap variasi jarak antara 1 buah,dengan total benda uji sebanyak 5 buah. Hubungan antara elemen batang tekan gandamenggunakan alat sambung baut. Kondisi ujung-ujung benda uji berupa sendi. Pembebabananyang diberikan adalah beban sentris yang diberi secara bertahap. Dari hasil pengujian ini akandidapat data beban dan lendutan. Sebelum dilakukan pengujian batang tekan ganda terlebih dahuludilakukan pengujian specimen batang tekan kayu Keruing dengan ukuran 5 x 5 x 20 cm sebanyak5 buah. Dari hasil penelitian ini didapat tegangan tekan rata-rata kayu Keruing sebesar 377,144kg/cm2. Kuat tekan batang ganda maksimum terjadi pada jarak antara 1,5 kali tebal kayu atau 4,5cm. Pada jarak antara batang tekan ganda 2 kali tebal kayu atau 6 cm mulai mengalami penurunan,tetapi hasil ini masih lebih tinggi dari batang tekan ganda yang tanpa jarak antara. Hasil pengujianbatang tekan ganda lebih kecil dari hasil perhitungan teoritis dengan menggunakan teganganabsolut yang didapat dari pengujian tekan specimen, dan lebih besar dari hasil perhitungan teoritisdengan menggunakan tegangan ijin tekan kayu berdasarkan PKKI 1961. Dari hasil penelitian initegangan ijin tekan pada PKKI 1961 aman untuk digunakan pada perhitungan batang tekan ganda

Regulasi Keamanan Hayati Produk Rekayasa Genetik Di Indonesia

EnglishGenetically Modified Organism (GMO) has been believed to enhance human life quality and prosperity. GMO is any organism whose genetic material has been altered by the application of recombinant DNA technology or genetic engineering. This technology can be used to improve plant resistance to biotic and abiotic stresses, biofortification and production of pharmaceuticals. Rice resistant to stem borer, papaya resistant to papaya ringspot virus, soybean resistant to herbicide, and Golden rice that contains beta carotene are the example of GMOs. However, the use of GMO still raises public concern on whether the GMO might pose a risk to environment, biodiversity, human, and animal health or not. For that reason, countries will enforce precautionary approach in utilization of GMO either for research or commercial by implementing the existing or new regulations in the country. In Indonesia, Government Regulation of the Republic of Indonesia Number 21 year of 2005 (PP No. 21/2005) on Biosafety of GMO, had been established. Biosafety of GMO includes environmental safety, food safety and/or feed safety. The enforcement of PP No. 21/2005 is to prevent potential adverse risks to biodiversity as a result of the utilization of GMO and to prevent the negative risks to human, animal, and fish health as a result of production process, preparation, storage, distribution, and utilization of GMO. This paper gives the overview of Indonesia\u27s regulation on the biosafety of GMO and the current status of GMO in Indonesia.IndonesiaProduk Rekayasa Genetik (PRG) diakui memiliki potensi besar untuk peningkatan kehidupan dan kesejahteraan manusia. PRG adalah organisme yang telah mengalami modifikasi genetik dengan menggunakan teknologi DNA rekombinan atau rekayasa genetik. Teknologi rekayasa genetik dapat digunakan untuk meningkatkan ketahanan tanaman terhadap cekaman biotik dan abiotik, biofortifikasi dan produksi bahan farmasi. Padi tahan hama penggerek batang, pepaya tahan penyakit papaya ringspot virus, kedelai toleran herbisida, dan Golden rice yang mengandungbeta carotene adalah contoh-contoh PRG yang telah dikembangkan. Namun demikian, pemanfaatan tanaman PRGmasih mengundang kekhawatiran masyarakat bahwa produk tersebut mungkin dapat menimbulkan risiko terhadap lingkungan, keanekaragaman hayati, kesehatan manusia dan hewan. Sehubungan dengan itu, secara global pemanfaatan dan peredaran PRG baik untuk tujuan penelitian dan pengembangan maupun komersial diatur oleh peraturan Perundang-undangan atau pedoman yang baru atau yang sudah ada dan berlaku dalam suatu negara. Di Indonesia, telah disahkan Peraturan Pemerintah Republik Indonesia No. 21 Tahun 2005 tentang Keamanan Hayati PRG yang diberlakukan baik untuk PRG yang diintroduksi dari luar negeri maupun hasil riset nasional. Keamanan hayati PRG adalah kemanan lingkungan, keamanan pangan, dan/atau keamanan pakan. Pemberlakuan PP No. 21/2005 ditujukan untuk mencegah kemungkinan timbulnya risiko yang merugikan bagi keanekaragaman hayatisebagai akibat pemanfatan PRG dan mencegah timbulnya risiko yang merugikan dan membahayakan kesehatan manusia dan hewan dan ikan sebagai akibat dari proses produksi, penyiapan, penyimpanan, peredaran, dan pemanfaatan pangan PRG. Dalam artikel ini diuraikan mengenai regulasi yang berlaku di Indonesia terkait dengan keamanan hayati PRG beserta lembaga otoritas yang dibentuk dan status PRG di Indonesia

Interaction between current imbalance and magnetization in LHC cables

The quality of the magnetic field in superconducting accelerator magnets is associated with the properties of the superconducting cable. Current imbalances due to coupling currents ¿I, as large as 100 A, are induced by spatial variations of the field sweep rate and contact resistances. During injection at a constant field all magnetic field components show a decay behavior. The decay is caused by a diffusion of coupling currents into the whole magnet. This results in a redistribution of the transport current among the strands and causes a demagnetization of the superconducting cable. As soon as the field is ramped up again after the end of injection, the magnetization rapidly recovers from the decay and follows the course of the original hysteresis curve. In order to clarify the interactions between the changes in current and magnetization during injection the authors performed a number of experiments. A magnetic field with a spatially periodic pattern was applied to a superconducting wire in order to simulate the coupling behavior in a magnet. This model system was placed into a stand for magnetization measurements and the influence of different powering conditions was analyze