Adjustment of the basin-scale circulation at 26 degrees N to variations in Gulf Stream, deep western boundary current and Ekman transports as observed by the Rapid array

The Rapid instrument array across the Atlantic Ocean along 26 degrees N provides unprecedented monitoring of the basin-scale circulation. A unique feature of the Rapid array is the combination of full-depth moorings with instruments measuring temperature, salinity, pressure time series at many depths with co-located bottom pressure measurements so that dynamic pressure can be measured from surface to bottom. Bottom pressure measurements show a zonally uniform rise (and fall) of bottom pressure of 0.015 dbar on a 5 to 10 day time scale, suggesting that the Atlantic basin is filling and draining on a short time scale. After removing the zonally uniform bottom pressure fluctuations, bottom pressure variations at 4000 m depth against the western boundary compensate instantaneously for baroclinic fluctuations in the strength and structure of the deep western boundary current so there is no basin-scale mass imbalance resulting from variations in the deep western boundary current. After removing the mass compensating bottom pressure, residual bottom pressure fluctuations at the western boundary just east of the Bahamas balance variations in Gulf Stream transport. Again the compensation appears to be especially confined close to the western boundary. Thus, fluctuations in either Gulf Stream or deep western boundary current transports are compensated in a depth independent (barotropic) manner very close to the continental slope off the Bahamas. In contrast, compensation for variations in wind-driven surface Ekman transport appears to involve fluctuations in both western basin and eastern basin bottom pressures, though the bottom pressure difference fluctuations appear to be a factor of 3 too large, perhaps due to an inability to resolve small bottom pressure fluctuations after removal of larger zonal average, baroclinic, and Gulf Stream pressure components. For 4 tall moorings where time series dynamic height (geostrophic pressure) profiles can be estimated from sea surface to ocean bottom and bottom pressure can be added, there is no general correlation between surface dynamic height and bottom pressure. Dynamic height on each mooring is strongly correlated with sea surface height from satellite observations and the variability in both dynamic height and satellite sea surface height decrease sharply as the western boundary is approached

Pemodelan Numerik Cfd pada Lambung Torpedo

Torpedo pada umumnya berbentuk tabung yang memiliki sistem penggerak sendiri. Torpedo yang dianalisa ini merupakan perpaduan dari desain torpedo jenis MK-44 dan MK-46 menjadi sebuah desain baru yang diharapkan dapat memperoleh performa yang lebih optimal. Dengan menggunakan perangkat lunak berbasis numerik CFD dapat dianalisa efek hidrodinamika yang timbul pada torpedo seperti: distribusi tekanan yang terjadi pada lambung torpedo, arah aliran fluida saat torpedo bergerak, streamline desain torped

Studi Kelayakan Desain Kapal Hisap Tambang

Feasibility study menjadi salah satu langkah penting diawal perencanaan pembangunan kapal. Karena dengan melakukan feasibility study maka akan didapatkan perhiutngan awal gaya-gaya yang akan bekerja pada badan kapal. Pada paper ini feasibility study dilakukan pada kapal jenis Bore Hole Mining (BHM). Kapal BHM ini diharapkan mampu beroperasi pada kedalaman 60 m. Pada paper ini feasibility study yang dibahas adalah analisa stabilitas kapal BHM dan tegangan geser yang dialami kapal BHM kondisi Loadcase Departure, Loadcase Full Load, Loadcase Half Load dan Loadcase Arrival. Dari hasil dari feasibility study yang dilakukan, maka dapat diambil kesimpulan kapal BHM tidak memenuhi standart yang ditetapkan dalam hal stabilitas pada berbagai kondisi loadcase dimana Angle of Minimum GZ kurang dari yang disyaratkan IMO pada 25 deg. Sedangkan untuk shear stress pada berbagai kondisi loadcase masih memenuhi kreteria yang ditetapkan BKI yaitu kurang dari 100MPa

Analisa Bending Stress pada Submerged Floating Tunnel

Perhitungan dengan pemodelan Submerged Floating Tunnel (SFT) dengan menggunakan perangkat lunak berbasis metode elemen hingga. Analisa struktur terowongan apung menggunakan prinsip kerja dengan mendiskripsikan seluruh beban (force) pada SFT berupa beban internal dan eksternal yang bekerja akan diperoleh momen reaksi yang terjadi sepanjang badan SFT, dengan mengetahui luas penampang melintang SFT maka dapat diperoleh bending stress di seluruh badan SFT.Keywords : submerged floating tunnel (SFT), bending stress, structural analysi

Socioeconomic position, John Henryism, and incidence of acute myocardial infarction in Finnish men

Previous cross-sectional studies examining whether John Henryism (JH), or high-effort coping with socioeconomic adversity, potentiates the inverse association between socioeconomic position (SEP) and cardiovascular health have focused mainly on hypertension in African Americans. We conducted the first longitudinal test of this hypothesis on incident acute myocardial infarction (AMI) using data from the Kuopio Ischemic Heart Disease Risk Factor Study in Finland (N = 1405 men, 42-60 years). We hypothesized that the expected inverse gradient between SEP and AMI risk would be stronger for men scoring high on JH than for those scoring low. John Henryism was measured by a Finnish version of the JH Scale for Active Coping. Four different measures of SEP were used: childhood SEP, education, income, and occupation. AMI hazard ratios (HR) by SEP and JH were estimated using COX proportional hazard models, before and after adjustment for study covariates. 205 cases of AMI occurred over a median of 14.9 years. Men employed in lower rank (farmer, blue-collar) occupations who scored high on JH had significantly higher age-adjusted risks of AMI than men in higher rank (white-collar) occupations (HR = 3.14, 95% CI: 1.65-5.98 for blue collar; HR = 2.33, 95% Cl: 1.04-5.22 for farmers) who also scored high on JH. No socioeconomic differences in AMI were observed for men who scored low on JH (HR = 136, 95% CI: 0.74 2.47 for blue collar; HR = 0.93, 95% CI: 0.59-1.48 for farmers; p = 0.002 for the SEP x JH interaction). These findings persisted after adjustment for sociodemographic, behavioral, and biological factors. Results for other SEP measures were in the same direction, but did not reach statistical significance. Repetitive high-effort coping with adversity (John Henryism) was independently associated with increased risk for AMI in Finnish men, underscoring the potential relevance of the John Henryism hypothesis to CVD outcomes other than hypertension and to populations other than African Americans. (C) 2016 Published by Elsevier Ltd.Peer reviewe

Pemodelan Numerik Hidroelastis Kapal Frigate

Kapal perang jenis frigate merupakan kapal cepat yang mempunyai froude number berkisar antara 0,4 – 0,5. Pengaruh beban slamming pada kerusakan kelelahan material cukup besar dan mengganggu kinerja peralatan elektronik maupun mekanik yang ada di kapal perang saat beroperasi. Pemodelan Hidroelastis Kapal Frigate ESC40DV dilakukan dengan menggunakan metode elemen hingga. Penelitian ini bertujuan untuk menghasilkan suatu model prototype struktur lambung kapal perang kelas frigate yang mempunyai tingkat kehandalan yang baik terhadap beban hidroelastis slamming melalui pengaturan bentuk rencana garis (lines plan) struktur lambung tersebut. Dalam penelitian ini nilai beban hidroelastis dianalisa melalui serangkaian perhitungan menggunakana metode numerik elemen hingga, dengan beban pendekatan memakai strip teori. Dari pemodelan diketahui bahwa moda ke-dua kering (dry mode) getaran untuk frigate sebesar 5.2267 Hz dan saat di air mode ke-dua (wet mode) bergeser menjadi sebesar 5.7142 Hz dikarenakan adanya tambahan damping hidrodinamika. Respon harmonik slaming maksimum untuk tekanan dan tegangan struktur pada badan frigate terjadi pada 6,3 MPa dan 69.45 MP

Metropolitan Fragmentation and Health Disparities: Is There a Link?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90559/1/j.1468-0009.2011.00659.x.pd

The sintering temperature effect on the shrinkage behavior of cobalt chromium alloy

Problem Statement: Co-Cr based alloys which is well known for its high Young’s modulus, fatigue strength, wear resistance and corrosion resistance is an important metallic bio�material. However, till date there are only two type of Co-Cr alloy which are the castable and wrought cobalt alloy. Powder Metallurgy route for cobalt is expected to give better result of Co-Cr alloy. The purpose of this research was mainly to study the sintering temperature effect to the shrinkage behavior of Cobalt Chromium (Co-Cr) alloy of the powder metallurgy route. Approach: Co-Cr was produced following P/M route under sintering temperature of 1000, 1100, 1200, 1300 and 1400oC. The sintering time was fixed at 60 min. Several tests has been conducted to determine this effect such as the rate of shrinkage measurement, the bulk density and porosity percentage measurement, compression and hardness tests and micro structural study. Result: From the study, it was found that the sintering temperature has caused the shrinkage of Co-Cr. The increasing of the sintering temperature has caused to the increasing of shrinkage of Co-Cr. This has resulted to the reduction of the pore volume and hence increased it density. In conjunction to that, the strength and the hardness of Co-Cr was increased. Conclusion: Therefore, it is hope that it will bring new view of powder metallurgy Co-Cr alloy as bio-material

The sintering temperature effect on the shrinkage behavior of cobalt chromium alloy

Problem Statement: Co-Cr based alloys which is well known for its high Young’s modulus, fatigue strength, wear resistance and corrosion resistance is an important metallic bio�material. However, till date there are only two type of Co-Cr alloy which are the castable and wrought cobalt alloy. Powder Metallurgy route for cobalt is expected to give better result of Co-Cr alloy. The purpose of this research was mainly to study the sintering temperature effect to the shrinkage behavior of Cobalt Chromium (Co-Cr) alloy of the powder metallurgy route. Approach: Co-Cr was produced following P/M route under sintering temperature of 1000, 1100, 1200, 1300 and 1400oC. The sintering time was fixed at 60 min. Several tests has been conducted to determine this effect such as the rate of shrinkage measurement, the bulk density and porosity percentage measurement, compression and hardness tests and micro structural study. Result: From the study, it was found that the sintering temperature has caused the shrinkage of Co-Cr. The increasing of the sintering temperature has caused to the increasing of shrinkage of Co-Cr. This has resulted to the reduction of the pore volume and hence increased it density. In conjunction to that, the strength and the hardness of Co-Cr was increased. Conclusion: Therefore, it is hope that it will bring new view of powder metallurgy Co-Cr alloy as bio-material