5,317 research outputs found

    Analisis Pengaruh Ketebalan Nonconductive Coating Terhadap Kemampuan Pendeteksian Panjang Dan KedalamanRetak PadaFilletJoint Bracket KapalAluminium Menggunakan Pengujian Ultrasonik

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    Konstruksi kapal yang telah beroperasi seringkali terjadi cacat pada daerah lasnya.Cacat yang timbul seperti retak,seringterjadi tanpa disadari padasambungan las yang telah dilapisi cat sebelumnya.Retak tersebut dapat diperiksa menggunakan metode Ultrasonic testing tanpa menghilangkan cat yang terdapat pada sambungan las. Penelitian ini bertujuan untuk menganalisis pengaruh ketebalan cat tersebut terhadap pendeteksian retak dengan metode Ultrasonic testing padafillet joint di braket kapal aluminium.Scanning dilakukan pada face C dari spesimen uji. Pada setiap spesimen diberikan beberapa variasi ketebalan nonconductive coating yaitu 100 mikron, 200 mikron, 250 mikron dan 300 mikron dimana sebelum diberikan variasi ketebalan coating, spesimen terlebih dahulu diberikan retak buatan pada daerah toe las dengan variasi ukuran panjang 70 mm, 30 mm, 20 mm, dan 10 mm, dengan kedalaman 2 mm, 4 mm, 6 mm, dan 8 mm. Setelah itu tiap spesimen dilakukan pemeriksaan dengan menggunakan metode Ultrasonic testing (UT). Hasil penelitian ini menunjukkan bahwa terdapat pengaruh ketebalan nonconductive coating terhadap pendeteksian panjang dan kedalaman retak, dimana kemampuan pembacaan UT terhadap panjang retak pada spesimen dengan ketebalan nonconductive coating 100 mikron rata-rata sebesar 95,814 %, 200 mikron sebesar 89,510 %, 250 mikron sebesar 87,140 % dan 300 mikron sebesar 85,629 % dari ukuran panjang retak sebenarnya. Sedangkan kemampuan pembacaan UT terhadap kedalaman retak pada spesimen dengan ketebalan nonconductive coating 100 mikron rata-rata sebesar 99,219 %, 200 mikron sebesar 98,167 %, 250 mikron sebesar 97,396 % dan 300 mikron sebesar 96,625 % dari ukuran kedalaman crack sebenarnya. Hal ini disebabkan adanya pelemahan gelombang ultrasonik (atenuasi) pada saat gelombang ultrasonik melewati batas permukaan antara nonconductive coating dengan pelat aluminium yang mempunyai impedansi akustik berbeda maka akan terjadi pemantulan dan pembiasan gelombang ultrasonik. Sebagian energi gelombang ultrasonik juga akan hilang saat gelombang melewati interfaces material

    Analisis Kesiapan Individu dalam Implementasi Manajemen Pengetahuan di Instansi Pemerintah

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    Berkembangnya teknologi akan memberikan pengaruh yang signifikan terhadap segala macam data maupun informasi. Perputaran data dan informasi di era digital seperti sekarang ini membutuhkan pengelolaan yang tepat. Pengelolaan ini yang nantinya akan memberikan dampak, baik itu berupa dampak positif maupun negatif. Proses pengelolaan ini juga erat kaitannya dengan kesiapan individu. Individu yang siap akan dapat mengelola data dan informasi dengan baik, begitu pula sebaliknya. Penelitian ini bertujuan untuk mengetahui kesiapan individu dalam implementasi manajemen pengetahuan. Penelitian dilakukan dengan menggunakan model dan alat ukur yang sudah diteliti pada penelitian sebelumnya. Alat ukur yang digunakan menggunakan model Knowledge Management Konseptual yang digabungkan dengan Technologi Readiness Index (TRI). Hasil dari penelitian ini menerangkan bahwa individu dalam instansi pemerintah (B2P2BPTH) masih belum siap dalam implementasi manajemen pengetahuan

    Line Intensities and Molecular Opacities of the FeH F4Δi−X4ΔiF^4\Delta_i-X^4\Delta_i Transition

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    We calculate new line lists and opacities for the F4Δi−X4ΔiF^4\Delta_i-X^4\Delta_i transition of FeH. The 0-0 band of this transition is responsible for the Wing-Ford band seen in M-type stars, sunspots and brown dwarfs. The new Einstein A values for each line are based on a high level ab initio calculation of the electronic transition dipole moment. The necessary rotational line strength factors (H\"onl-London factors) are derived for both the Hund's case (a) and (b) coupling limits. A new set of spectroscopic constants were derived from the existing FeH term values for v=0, 1 and 2 levels of the XX and FF states. Using these constants extrapolated term values were generated for v=3 and 4 and for JJ values up to 50.5. The line lists (including Einstein A values) for the 25 vibrational bands with v≀\leq4 were generated using a merged list of experimental and extrapolated term values. The FeH line lists were use to compute the molecular opacities for a range of temperatures and pressures encountered in L and M dwarf atmospheres. Good agreement was found between the computed and observed spectral energy distribution of the L5 dwarf 2MASS-1507.Comment: 52 pages, 3 figures, many tables, accepted for publication in the Astrophysical Journal Supplement

    Quantitative atomic spectroscopy for primary thermometry

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    Quantitative spectroscopy has been used to measure accurately the Doppler-broadening of atomic transitions in 85^{85}Rb vapor. By using a conventional platinum resistance thermometer and the Doppler thermometry technique, we were able to determine kBk_B with a relative uncertainty of 4.1×10−44.1\times 10^{-4}, and with a deviation of 2.7×10−42.7\times 10^{-4} from the expected value. Our experiment, using an effusive vapour, departs significantly from other Doppler-broadened thermometry (DBT) techniques, which rely on weakly absorbing molecules in a diffusive regime. In these circumstances, very different systematic effects such as magnetic sensitivity and optical pumping are dominant. Using the model developed recently by Stace and Luiten, we estimate the perturbation due to optical pumping of the measured kBk_B value was less than 4×10−64\times 10^{-6}. The effects of optical pumping on atomic and molecular DBT experiments is mapped over a wide range of beam size and saturation intensity, indicating possible avenues for improvement. We also compare the line-broadening mechanisms, windows of operation and detection limits of some recent DBT experiments

    Influences of state anxiety on gaze behavior and stepping accuracy in older adults during adaptive locomotion

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    This article is available open access through the publisher’s website at the link below. Copyright © The Authors 2011.OBJECTIVES: Older adults deemed to be at a high risk of falling transfer their gaze from a stepping target earlier than their low-risk counterparts. The extent of premature gaze transfer increases with task complexity and is associated with a decline in stepping accuracy. This study tests the hypothesis that increased anxiety about upcoming obstacles is associated with (a) premature transfers of gaze toward obstacles (i.e., looking away from a target box prior to completing the step on it in order to fixate future constraints in the walkway) and (b) reduced stepping accuracy on the target in older adults. METHODS: High-risk (9) and low-risk (8) older adult participants walked a 10-m pathway containing a stepping target area followed by various arrangements of obstacles, which varied with each trial. Anxiety, eye movements, and movement kinematics were measured. RESULTS: Progressively increasing task complexity resulted in associated statistically significant increases in measures of anxiety, extent of early gaze transfer, and stepping inaccuracies in the high-risk group. DISCUSSION: These results provide evidence that increased anxiety about environmental hazards is related to suboptimal visual sampling behavior which, in turn, negatively influences stepping performance, potentially contributing to increased falls risk in older adults.Biotechnology and Biological Sciences Research Counci

    Technical Change, Investment and Energy Intensity

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    Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).This paper analyzes the role of different components of technical change on energy intensity by applying a Translog variable cost function setting to the new EU KLEMS dataset for 3 selected EU countries (Italy, Finland and Spain). The framework applied represents an accounting of technical change components, comprising autonomous as well as embodied and induced technical change. The inducement of embodied technical change is introduced by an equation for the physical capital stock that is a fixed factor in the short-run. The dataset on capital services and user costs of capital in EUKLEMS enables explaining capital accumulation depending on factor prices. The model can be used for explaining and tracing back the long-run impact of prices and technical change on energy intensity.This paper is based on the EU KLEMS database, which has been funded by the European Commission, Research Directorate General as part of the 6th Framework Programme, Priority 8, “Policy Support and Anticipating Scientific and Technological Needs” (project 502049)

    One-Loop Supergravity Corrections to the Black Hole Entropy and Residual Supersymmetry

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    We study the one-loop corrections to the effective on-shell action of N=2 supergravity in the background of the Reissner-Nordstrom black hole. In the extreme case the contributions from graviton, gravitino and photon to the one-loop corrections to the entropy are shown to cancel. This gives the first explicit example of the supersymmetric non-renormalization theorem for the on-shell action (entropy) for BPS configurations which admit Killing spinors. We display the residual supersymmetry of the perturbations of a general supersymmetric theory in a bosonic BPS background.Comment: 13 Pages, LaTe

    Factors influencing anaemia in dialysis patients. A special survey by the EDTA-ERA Registry

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    The European Dialysis and Transplantation Association—European Renal Association (EDTA-ERA) Registry conducted a special study on anaemia in dialysis patients because it seemed important to elucidate the various factors that influence the degree of anaemia and the use of regular transfusions in dialysis patients before the introduction of recombinant human erythropoietin (rHuEpo) for larger groups of patients. In a 20% sample of all patients recorded to have been dialysed throughout 1987, statistically significant associations could be found by multifactorial analysis between haemoglobin (Hb) concentration and age, sex, primary renal disease, type of treatment, hours of dialysis per week, and number of years on renal replacement therapy. The type of dialyser membrane did not seem to play a role (although there was weak evidence of an effect of the dialyser). Mean Hb concentration for dialysis patients differed between countries as did the transfusion policy. In view of the high costs of the rHuEpo treatment and potential side-effects, factors such as method of dialysis and hours of haemodialysis per week should be taken into consideration in the treatment of anaemia in dialysis patient

    Demography of Dialysis and Transplantation in Children in Europe, 1985: Report from the European Dialysis and Transplant Association Registry

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    At the end of 1985 there were 5482 patients known to the Registry who started renal replacement therapy (RRT) between the ages of 6 months and 15 years. Of these, approximately 25% had died, 30% were still aged less than 15 years, and the other 45% were older. The acceptance rate of new patients over the last 10 years has slowly but steadily increased; six new paediatric patients per million child population probably represents the likely needs of the near future. Hospital haemodialysis remained the main form of renal replacement therapy in new patients, while 3 years after start of RRT, transplantation became the most frequently used replacement therapy; CAPD appeared to be used mainly in children with a short waiting time for transplantation. Out of the 384 grafts reported in 1985, only 16% were from living related donors; among 321 cadaver grafts, 24% were second and only 3% were third grafts. Glomerulonephritis and pyelonephritis accounted for 50% of all primary renal diseases. During the last 5 years, the proportion with glomerulonephritis seems to have decreased slightly. Hyperkalaemia and fluid overload have still to be considered the main causes of death. Only in 17% of all cases was the cause of death reported as unknown or undetermine
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