Design of an unmanned, reusable vehicle to de-orbit debris in Earth orbit

The space debris problem is becoming more important because as orbital missions increase, the amount of debris increases. It was the design team's objective to present alternative designs and a problem solution for a deorbiting vehicle that will alleviate the problem by reducing the amount of large debris in earth orbit. The design team was asked to design a reusable, unmanned vehicle to de-orbit debris in earth orbit. The design team will also construct a model to demonstrate the system configuration and key operating features. The alternative designs for the unmanned, reusable vehicle were developed in three stages: selection of project requirements and success criteria, formulation of a specification list, and the creation of alternatives that would satisfy the standards set forth by the design team and their sponsor. The design team selected a Chain and Bar Shot method for deorbiting debris in earth orbit. The De-orbiting Vehicle (DOV) uses the NASA Orbital Maneuvering Vehicle (OMV) as the propulsion and command modules with the deorbiting module attached to the front

APLIKASI ADMINISTRASI BENGKEL BERBASIS ANDROID DAN WEB STUDI KASUS BENGKEL BUBUT FAJAR TEKNIK

Pengelolaan administrasi yang berjalan di Bengkel Bubut Fajar Teknik masih manual, sedangkan data administrasi yang ada sangat banyak. Resiko kehilangan data administrasinya tinggi karena data yang ada hanya berupa arsip dan nota. Pelayanan jasa kepada pelanggan menjadi kurang maksimal. Penelitian ini dilakukan dengan cara menganalisis dan merancang aplikasi administrasi. Kemudian membangun dan mengimplementasikannya pada Bengkel Bubut Fajar Teknik. Aplikasi ini digunakan untuk mengolah data administrasi dan berjalan pada web dan Android. Aplikasi pada web (server) digunakan untuk melihat, mencari, menambah, mengubah dan menghapus data bengkel, transaksi, dan laporan. Aplikasi pada Android (client) hanya digunakan oleh pemilik sebagai penampil data bengkel, transaksi, dan laporan. Hasil yang didapat adalah sebuah aplikasi administrasi yang dapat memudahkan Bengkel Bubut Fajar Teknik dalam mengelola data administrasinya. Sehingga resiko kehilangan data berkurang dan meningkatkan kualitas pelayanan jasa kepada pelanggan

Time-resolved RHEED Studies of the Growth of Epitaxial ZnSe Films on GaAs By Pulsed Laser Deposition

Film growth consists of two basic processes, deposition and surface relaxation, with opposing effects on the evolution of surface roughness. The pulsed-laser deposition (PLD) growth process has the unique feature of having periods of very high deposition rates on ms time scales followed by periods, on the order of seconds, with only surface relaxation. In this paper we report the first efforts towards exploiting this unique feature to study these two basic processes independently. Thin epitaxial films of ZnSe were grown using PLD on (001) GaAs and 2° miscut (001) GaAs substrates. For growth on both the singular and vicinal surfaces, RHEED patterns taken following growth showed clear, streaky first zone and sharp second zone spots, and well-defined Kikuchi lines; these features are indicative of a smooth growth surface and high quality film. No reconstruction of the growth surface was observed, in contrast to behavior observed in molecular beam epitaxy. Time-resolved RHEED measurements show that a single morphology developed during growth on singular (001) GaAs. However, during growth on miscut (001) GaAs, two morphologies developed, one transitory and one appearing to evolve towards steady state. When growth on the miscut substrate was stopped, recovery of the RHEED signal was observed. The rate of recovery could be attributed to two relaxation processes, as differentiated by their time constants. Potential origins of these observations are discussed.Engineering and Applied Science

Exact decoding for phrase-based statistical machine translation

© 2014 Association for Computational Linguistics. The combinatorial space of translation derivations in phrase-based statistical machine translation is given by the intersection between a translation lattice and a target language model. We replace this intractable intersection by a tractable relaxation which incorporates a low-order upperbound on the language model. Exact optimisation is achieved through a coarseto- fine strategy with connections to adaptive rejection sampling. We perform exact optimisation with unpruned language models of order 3 to 5 and show searcherror curves for beam search and cube pruning on standard test sets. This is the first work to tractably tackle exact optimisation with language models of orders higher than 3

Ultracold scattering processes in three-atomic helium systems

We review results on scattering observables for $^4$He--$^4$He$_2$ and $^3$He--$^4$He$_2$ collisions. We also study the effect of varying the coupling constant of the atom-atom interaction on the scattering length

High-quality variational wave functions for small 4He clusters

We report a variational calculation of ground state energies and radii for 4He_N droplets (3 \leq N \leq 40), using the atom-atom interaction HFD-B(HE). The trial wave function has a simple structure, combining two- and three-body correlation functions coming from a translationally invariant configuration-interaction description, and Jastrow-type short-range correlations. The calculated ground state energies differ by around 2% from the diffusion Monte Carlo results.Comment: 5 pages, 1 ps figure, REVTeX, submitted to Phys. Rev.

An ultrafast 1 x M all-optical WDM packet-switched router based on the PPM header address

This paper presents an all-optical 1 x M WDM router architecture for packet routing at multiple wavelengths simultaneously, with no wavelength conversion modules. The packet header address adopted is based on the pulse position modulation (PPM) format, thus enabling the use of only a singlebitwise optical AND gate for fast header address correlation. It offers multicast as well as broadcast capabilities. It is shown that a high speed packet routing at 160 Gb/s can be achieved with a low channel crosstalk (CXT) of ~ -27 dB at a channel spacing of greater than 0.4 THz and a demultiplexer bandwidth of 500 GHz

Polyethersulfone/HFO mixed matrix membrane for enhanced oily wastewater rejection

The recent growth of oil and gas industry has led to the increase of oily wastewater release. Membrane technology has been in the spotlight in recent advancement to treat the oily wastewater. Fouling due to surfactant adsorption and/or oil droplets plugging the pore has become one of the major hindrances in most of the research on oily wastewater treatment. In this work, self-synthesized hydrous ferric dioxide nanoparticles (HFO NPs) via chemical precipitation method were incorporated in polyethersulfone (PES) to fabricate a novel nanocomposite mixed matrix membranes (MMMs) for ultrafiltration (UF). The morphologies and physicochemical properties of prepared HFO NPs and MMMs were characterized using Scanning Electron Microscopy (SEM) and Transmission electron microscope (TEM), contact angle goniometer, before further subjected to water permeation test and oil rejection test. It was found that contact angle of membrane decreased remarkably with an increase in HFO nanoparticle loading from 70° to 38° at which proved its improved hydrophilicity which led to a significant rise in permeate flux, achieving 168.06 L/m2h bar in comparison to 63.67 L/m2h bar shown by the plain PES membrane. Total rejection of oil (100% rejection) demonstrated by the MMMs has confirmed the superior potential of PES/HFO UF membrane for total purification of oily wastewater especially to be reused in oilfield and refinery processes as well as to be released to the environment

Low loss waveguide-based Butler matrix with iris coupling control method for millimeterwave applications

This paper proposes a low loss 4×4 Butler matrix based on rectangular waveguide cavity resonators technology for millimeterwave beamforming network using iris coupling method. This method has the advantage of controlling the electrical fields and the coupling factor inside a complex medium such as waveguide cavity resonators. The coupling factor of 6 dB for 4×4 Butler matrix is achieved by tuning the iris coupling k-value between the waveguide cavity resonators. Thus, avoiding a higher phase difference losses and component losses at upper millimeterwave bands. To validate the proposed method, CST software simulations are performed under several iris coupling k-values to achieve a 6 dB coupling factor. Then, the proposed 4×4 Butler matrix is 3D metal printed using selective laser melting (SLM) technique. The measured reflection and isolation coefficients are observed below −10 dB, with coupling coefficients ranging between −6 and −7 dB. The phase differences of −42.02°, 42.02°, −130.95°, and 133.3° are achieved at the outputs. It confirmed that using this proposed method has the superiority over the conventional microstrip and waveguide coupling methods by a 1 dB coupling factor loss and a 3° phase difference error

Hubungan Pengetahuan dan Sikap terhadap Tindakan Tentang Pap Smear dan Inspeksi Visual Asetat pada Wanita Pekerja Seksual Tidak Langsung di Hotspot X Kecamatan Marpoyan Damai Pekanbaru sebagai Deteksi Dini Kanker Serviks

Cervical cancer is a Malignancy grows in the cervix. Cervical cancer ranks as the fourth most common cancer in women worldwide. This disease can be detected early by Pap smear and Visual Inspection with Acetic Acid (VIA). Indirect female sex worker (FSW) have a higher risk of cervical cancer. The aim of this study is to reveal the correlation between knowledge and attitude towards the behaviour of indirect FSW at hotspot X District Marpoyan Damai Pekanbaru about Pap smear and VIA as an early detection of cervical cancer. The method of this research is analytic corss sectional. Population is indirect FSW living in the hotspot X and samples were taken with total sampling method to 43 people trough interviews using questionnaire. The results showed that among 43 FSWs, 28 people (65.1%) aged less than 26 years old, 25 people (58.2%) have Junior High School (JHS), 21 people (48.8%) have poor knowledge, 24 people (55.8%) have a negative attitude and 33 people (76.7%) did test. There is no correlation between knowledge and attitude (p=0.063), no correlation between knowledge and behaviour (p=1.000) and no correlation between attitude and behaviour (p=0.302). it is concluded that the majority of indirect FSW at hotspot X have bad knowledge, negative attitude but have behaviour an early detection of cervical cance