4,199 research outputs found
Tuning the structural and dynamical properties of a dipolar Bose-Einstein condensate: Ripples and instability islands
It is now well established that the stability of aligned dipolar Bose gases
can be tuned by varying the aspect ratio of the external harmonic confinement.
This paper extends this idea and demonstrates that a Gaussian barrier along the
strong confinement direction can be employed to tune both the structural
properties and the dynamical stability of an oblate dipolar Bose gas aligned
along the strong confinement direction. In particular, our theoretical
mean-field analysis predicts the existence of instability islands immersed in
otherwise stable regions of the phase diagram. Dynamical studies indicate that
these instability islands, which can be probed experimentally with present-day
technology, are associated with the going soft of a Bogoliubov--de Gennes
excitation frequency with radial breathing mode character. Furthermore, we find
dynamically stable ground state densities with ripple-like oscillations along
the radial direction. These structured ground states exist in the vicinity of a
dynamical radial roton-like instability.Comment: 9 pages, 11 figure
IS THERE POTENTIAL FOR REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION (rTMS) AS A TREATMENT OF OCD?
Obsessive-Compulsive Disorder (OCD) is a common and highly debilitating psychiatric disorder. Amongst OCD sufferers are a
significant number (40-60%) of so-called non-responders who do not fully respond to commonly available treatments, which include medications (Selective Serotonin Reuptake Inhibitors-SSRIs) and cognitive behavior therapy (CBT). Modern \u27neuromodulatory\u27 techniques such as Deep Brain Stimulation (DBS), repetitive Transcranial Magnetic Stimulation (rTMS) and transcranial Direct Current Stimulation (tDCS) potentially offer alternative forms of treatment for OCD patients who either do not respond to, or are unable or unwilling to take SSRIs and undergo CBT. Although shown to be effective in treatment resistant OCD, DBS requires invasive neurosurgical procedures with associated risks. On the other hand, rTMS and tDCS are non-invasive forms of treatment, which are largely risk free, but the evidence of their efficacy so far is somewhat limited, with only small number of published studies. In this brief survey we will address the potential of rTMS as a therapeutic tool for OCD and review the published literature on the cortical targets for rTMS used so far. We will also discuss some of the newer variants of rTMS techniques only a few of which have been employed so far, and speculate whether there might be a place for rTMS as a standard treatment in OCD, along side CBT, SSRIs and DBS
Experience can increase prism fusion range
Aim: Differences in near prism fusion ranges (PFR) were assessed in 4 groups of participants who differed in experience of exposure to such testing. The effect of encouragement in the two least experienced groups was also tested.
Methods: The near base in (BI) and base out (BO) fusional amplitudes (FA) were measured in four groups of 10 participants, all with normal or corrected to normal vision. One group was naÏve to such testing, being non-orthoptic students, the other three groups consisted separately of Year One, Two and Three student orthoptists. The two most inexperienced groups, NaÏve and Year One student orthoptists, were also tested a second time with encouragement to try as hard as possible to increase their fusion amplitudes.
Results: Year Two and Year Three students had significantly ( p < 0.001, often over 20∆) larger BO FA than naÏve students or Year One orthoptic students. No such differences were seen for BI measures. Encouragement also significantly ( p < 0.01), but modestly (<6∆), increased BO FA and slightly (about 1∆, p < 0.05) increased BI FA.
Conclusions: Experience did increase PFR but this was mainly in BO fusion amplitudes and was far greater than obtained by encouraging participants. The experience needed to obtain this increase appeared to be the exposure occurring in one year of training to be an orthoptist. Further experiments could help clarify the factors involved in this improvement by tracking any increase throughout this first year and also look for changes in performance in other orthoptic tests
Case study of active array feed compensation with sidelobe control for reflector surface distortion
The feasibility of electromagnetically compensating for reflector surface distortions has been investigated. The performance characteristics (gain, sidelobe levels, etc.) of large communication antenna systems degrade as the reflector surface distorts mainly due to thermal effects from a varying solar flux. The techniques described in this report can be used to maintain the design performance characteristics independently of thermal effects on the reflector surface. With the advent of monolithic microwave integrated circuits (MMIC), a greater flexibility in array-fed reflector system design can be achieved. MMIC arrays provide independent control of amplitude and phase for each of many radiating elements of the feed array. It is assumed that the surface characteristics (x,y,z, its first and second derivatives) under distorted conditions are known
Pengaruh Rasio Panjang Dan Jarak Antar Plate Settler Terhadap Efisiensi Penyisihan Total Suspended Solids (Tss) Pada Reaktor Sedimentasi Rectangular
Air bersih menjadi salah satu kebutuhan yang mendasar bagi kehidupan manusia. Sebagian besar sumber air baku berasal dari air permukaan yang mengandung material diskrit seperti kerikil, pasir, koloid, dan partikel – partikel tersuspensi (total suspended solid) yang menyebabkan kekeruhan pada badan air, sehingga dalam penurunan padatan tersuspensi diperlukan bak sedimentasi. Masalah yang sering ditimbulkan yaitu bak sedimentasi konvensional membutuhkan lahan yang luas, sedangkan lahan yang tersedia terbatas. Oleh karena itu perlu memodifikasi bak sedimentasi konvensional salah satu cara yaitu dengan menambahkan plate settler. Plate settler memiliki kriteria desain rasio panjang dan jarak antar plate settler. Namun belum diketahui rasio panjang dan jarak antar plate settler yang menghasilkan efisiensi penyisihan TSS optimal. Penelitian ini dilakukan menggunakan rangkaian reaktor yang terdiri dari reaktor koagulasi, reaktor flokulasi, dan reaktor sedimentasi sistem kontinyu dengan debit pengolahan 10 mL/detik. Variasi yang digunakan pada penelitian ini yaitu panjang plate setter (lp) 10 cm ; 20 cm ; dan 30 cm dan jarak antar plate settler (dp) 1 cm ; 2 cm ; 3,25 cm ; 5,5 cm ; dan 7,25 cm. Kombinasi dari kedua variasi tersebut menghasilkan rasio panjang dan jarak antar plate settler atau rasio lp/dp 1,4 ; 1,8 ; 2,7 ; 2,8 ; 3,6 ; 4,1 ; 5 ; 5.3 ; 5,5 ; 8 ; 10 ; 15 ; 20 ; dan 30. Lokasi penelitian dan air baku yang digunakan yaitu air Waduk Pendidikan Diponegoro. Hasil penelitian menunjukkan bahwa rasio panjang dan jarak antar plate settler atau rasio lp/dp optimal adalah 15. Rasio lp/dp 15 merupakan hasil kombinasi dari panjang plate settler 30 cm dan jarak antar plate settler 2 cm. Panjang, jarak antar plate settler, dan rasio lp/dp tersebut mampu menghasilkan efisiensi penyisihan TSS sebesar 62% dan efisiensi penyisihan kekeruhan 34%, dengan biaya yaitu sebesar Rp 29.568,00
Pengaruh Penambahan Lindi dan Mol Nasi Basi terhadap Waktu Pengomposan Sampah Organik
Produksi sampah yang terus meningkat sedangkan teknologi pengolahan tidak efisien dan tidak ramah lingkungan serta lahan TPA (Tempat Pemrosesan Akhir) yang terbatas menjadi masalah utama di Indonesia. Volume sampah akan terus meningkat sehingga penimbunan yang dilakukan terus – menerus akan membuat umur TPA cepat habis.Salah satu solusi dari permasalahan sampah adalah dengan melakukan pengomposan sampah organik biodegradable yang dihasilkan.Pengomposan sampah organik biasanya membutuhkan waktu lama. Untuk mempercepat pengomposan ditambahkan lindi dan MOL nasi basi sebagai aktivator. Penelitian ini bertujuan untuk mengetahui dosis optimum lindi dan MOL nasi basi dan pengaruhnya terhadap waktu pengomposan sampah organik dengan metode Mac Donal. Hasil terbaik pengomposan adalah pada variasi K3 (bahan kompos + lindi 15 ml) yang menunjukkan kematangan berdasarkan rasio C/N pada minggu ke – 2 pengomposan. Kadar C – organik 17,00%; kadar N - total 1,36 %; Rasio C/N 12,47;kadar P - total0,306%; kadar K – total 3,64%; kadar Zn 4,69 ppm; kadar Fe 1,12 %; kadar Mn 0,012%; total coliform 46 MPN/gr
Kajian Teknis Timbulan, Komposisi, Dan Karakteristik Serta Rencana Pengelolaan Sampah Fakultas Teknik Universitas Diponegoro
Fakultas Teknik (FT) Universitas Diponegoro (Undip) merupakan salah satu fakultas terbesar di Undip yang berada di kawasan kampus Tembalang dengan luas wilayah sebesar 141.161 m2 dan jumlah warga kampus sebanyak 10.333 jiwa pada tahun 2015. Berdasarkan jenis kegiatan, sumber sampah FT dibagi menjadi 4 area yaitu kuliah, kantor, kantin dan taman. Tujuan dari penelitian ini adalah membangun desain sistem pengelolaan sampah yang baik dengan sasaran menganalisis timbulan, komposisi, dan karakteristik sampah dan mengevaluasi dan merencanakan sistem pengelolaan sampah FT. Metode pengukuran dan sampling sampah menggunakan SNI 19-3964-1994. Hasil kajian menunjukan bahwa timbulan sampah rata-rata sesuai kapasitas gedung yang dihasilkan kuliah adalah 327,347 kg/hari atau 5322,78 l/hari dengan komposisi berat sampah dominan adalah 41,54 % kertas, 38, 28 % plastik serta 7,69 % organik. Pada area kantor/ Dekanat dihasilkan 13,044 kg/hari atau 251,75 l/hari dengan komposisi berat sampah dominan adalah kertas52,07%. Pada area kantin dihasilkan 273,678 kg/hari atau 1662,15 L/hari dengan komposisi berat sampah dominan adalah organik sebesar 77,22 %. Sedangkan sampah dari hasil penyapuan taman dihasilkan 63,89 kg/hari atau 779,83 L/hari dengan komposisi keseluruhan berupa daun-daun. Pada penelitian ini, karakteristik sampah yang diuji antara lain densitas, kadar air, kadar abu dan nilai kalor. Hasil studi akan menjadi dasar dalam perencanaan pewadahan, pengumpulan, pemindahan, pengangkutan, aspek peran serta warga kampus dan rekomendasi pengolahan sampah pada tahun 2016 hingga 2035. Keseluruhan perencanaan membutuhkan total biaya sebesar Rp 7.148.084.85
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