6,330 research outputs found
Rayleigh number dependence of the Archimedes number dependent large-scale flow structure formation in mixed convection
No full textWe report on experimental investigations of large-scale flow structure formation in mixed convection. We characterize the flow field by measuring the velocity fields within a rectangular model room using 2D2C PIV. The control parameters are the Reynolds number Re, the Rayleigh number Ra and the Prandtl number Pr. All parameters are linked through the Archimedes number Ar. In 6.4x10-2 ≤ Ar ≤ 1.39x101, 4.2x103 ≤ Re ≤ 6.35x104 and Ra = 3.1x107, Ra = 1.8x108 and Pr = 0.713 we found flow 3 different flow structures. While keeping Ra and Pr constant and varying Ar through Re variations, we found an Ar dependence of the largescale flow structure formation within 6.4x10-2 ≤ Ar ≤ 1.39x101. Furthermore, we found a Ra dependence of the structure formation, which shifts the transition points between the structures to higher Archimedes numbers and reduces the mean velocities within the investigated domain
Reynolds numbers near the ultimate state of turbulent Rayleigh-Bénard convection
No full textWe report on measurements of the mean-flow Reynolds number ReU and the rms fluctuation Reynolds number ReV in turbulent Rayleigh-Bénard convection as a function of the Rayleigh number Ra for 4 x 1011 < Ra < 2 1014 and Pr ' 0:8. Both can be described by the same power law with an effective exponent = 0:44, in agreement with predictions for ReU but in disagreement with predictions for ReV
Pengaruh Pemberian Posisi Semi Fowler terhadap Perubahan Mean Arterial PrThe Effect of Giving the Semi Fowler Position on Changes in Mean Arterial Pressure in CHF Patients at Type A Hospital, West Kalimantan
No full textPemantauan hemodinamik memiliki peran penting dalam manajemen pasien dengan gagal jantung. Perubahan MAP (Mean Arterial Pressure) harus selalu dalam pemantauan. Penatalaksanaan keperawatan yang dapat dilakukan antara lain istirahatkan klien untuk mengurangi konsumsi oksigen, pantau tanda-tanda vital, edukasikan tentang keadaan yang terjadi pada klien agar tidak timbul kecemasan, atur posisi (positioning) yang nyaman bagi klien. Tujuan: Penelitian ini mengidentifikasi dan menganalisa Pengaruh Pemberian Posisi Semi Fowler Terhadap Perubahan Mean Arterial Pressure Pada Pasien CHF Rumah Sakit Type A Kalimantan Barat. Metode: penelitian memiliki desain quasy-experimental dengan kelompok kontrol berjenis non-equivalent. Pengukuran data dilakukan pre dan post test. Jumlah sampel yang dibutuhkan sebanyak 80 orang yang terbagi atas 2 kelompok, kelompok kontrol akan diberikan posisi supinasi, sementara kelompok intervensi akan diberikan posisi semi-fowler. Pemilihan sampel dilakukan secara purposive sampling. Uji statistik yang digunakan adalah paired sample t test terhadap penilaian nilai pre-post test, sementara menentukan efektivitas kedua kelompok, dilakukan pengujian menggunakan independent sample t test. Hasil : Uji statistik paired sample T, pada kelompok intervensi nilai MAP dari pre ke-post, terjadi perbedaan dengan significant nilai P = 0,013, (P < 0.005), sedangkan kelompok kontrol nilai MAP dari pre-post tidak terjadi perbedaan dengan nilai P= 0,980, (P>0.005). Kesimpulan: Terdapat pengaruh pemberian reposisi pasien dengan semi-fowler terhadap perubahan tekanan MAP.Ringkasan: Latar belakang: Pemantauan hemodinamik berperan penting dalam manajemen pasien CHF, khususnya perubahan Mean Arterial Pressure (MAP) yang memerlukan penatalaksanaan keperawatan optimal termasuk pengaturan posisi. Tujuan: Mengidentifikasi dan menganalisis pengaruh pemberian posisi semi-fowler terhadap perubahan MAP pada pasien CHF di Rumah Sakit Tipe A Kalimantan Barat. Metode: Quasi-experimental dengan desain non-equivalent control group pada 80 pasien (40 intervensi, 40 kontrol) menggunakan purposive sampling. Kelompok intervensi diberikan posisi semi-fowler 45°, kelompok kontrol posisi supinasi selama 1 jam. Analisis menggunakan paired sample t-test dan independent sample t-test. Hasil: Kelompok intervensi menunjukkan penurunan MAP signifikan (p=0,013; p<0,05) dari 91,42 mmHg menjadi 86,50 mmHg, sedangkan kelompok kontrol tidak signifikan (p=0,980; p>0,05). Simpulan: Posisi semi-fowler efektif menurunkan MAP pada pasien CHF. Saran: Implementasi posisi semi-fowler sebagai intervensi keperawatan standar untuk optimalisasi hemodinamik pasien CHF
Pengaruh Pemberian Posisi Semi Fowler terhadap Perubahan Mean Arterial PrThe Effect of Giving the Semi Fowler Position on Changes in Mean Arterial Pressure in CHF Patients at Type A Hospital, West Kalimantan
No full textPemantauan hemodinamik memiliki peran penting dalam manajemen pasien dengan gagal jantung. Perubahan MAP (Mean Arterial Pressure) harus selalu dalam pemantauan. Penatalaksanaan keperawatan yang dapat dilakukan antara lain istirahatkan klien untuk mengurangi konsumsi oksigen, pantau tanda-tanda vital, edukasikan tentang keadaan yang terjadi pada klien agar tidak timbul kecemasan, atur posisi (positioning) yang nyaman bagi klien. Tujuan: Penelitian ini mengidentifikasi dan menganalisa Pengaruh Pemberian Posisi Semi Fowler Terhadap Perubahan Mean Arterial Pressure Pada Pasien CHF Rumah Sakit Type A Kalimantan Barat. Metode: penelitian memiliki desain quasy-experimental dengan kelompok kontrol berjenis non-equivalent. Pengukuran data dilakukan pre dan post test. Jumlah sampel yang dibutuhkan sebanyak 80 orang yang terbagi atas 2 kelompok, kelompok kontrol akan diberikan posisi supinasi, sementara kelompok intervensi akan diberikan posisi semi-fowler. Pemilihan sampel dilakukan secara purposive sampling. Uji statistik yang digunakan adalah paired sample t test terhadap penilaian nilai pre-post test, sementara menentukan efektivitas kedua kelompok, dilakukan pengujian menggunakan independent sample t test. Hasil : Uji statistik paired sample T, pada kelompok intervensi nilai MAP dari pre ke-post, terjadi perbedaan dengan significant nilai P = 0,013, (P < 0.005), sedangkan kelompok kontrol nilai MAP dari pre-post tidak terjadi perbedaan dengan nilai P= 0,980, (P>0.005). Kesimpulan: Terdapat pengaruh pemberian reposisi pasien dengan semi-fowler terhadap perubahan tekanan MAP.Ringkasan: Latar belakang: Pemantauan hemodinamik berperan penting dalam manajemen pasien CHF, khususnya perubahan Mean Arterial Pressure (MAP) yang memerlukan penatalaksanaan keperawatan optimal termasuk pengaturan posisi. Tujuan: Mengidentifikasi dan menganalisis pengaruh pemberian posisi semi-fowler terhadap perubahan MAP pada pasien CHF di Rumah Sakit Tipe A Kalimantan Barat. Metode: Quasi-experimental dengan desain non-equivalent control group pada 80 pasien (40 intervensi, 40 kontrol) menggunakan purposive sampling. Kelompok intervensi diberikan posisi semi-fowler 45°, kelompok kontrol posisi supinasi selama 1 jam. Analisis menggunakan paired sample t-test dan independent sample t-test. Hasil: Kelompok intervensi menunjukkan penurunan MAP signifikan (p=0,013; p<0,05) dari 91,42 mmHg menjadi 86,50 mmHg, sedangkan kelompok kontrol tidak signifikan (p=0,980; p>0,05). Simpulan: Posisi semi-fowler efektif menurunkan MAP pada pasien CHF. Saran: Implementasi posisi semi-fowler sebagai intervensi keperawatan standar untuk optimalisasi hemodinamik pasien CHF
Logarithmic variance profiles and the corresponding f-1 spectra of temperature fluctuations in turbulent Rayleigh-Bénard convection
No full textWe report experimental results for the temperature variance 2(z) and the corresponding frequency spectra P(f) in turbulent Rayleigh-Bénard convection (RBC) in a cylindrical sample of aspect ratioT= D/L = 1:00 (D = 1:12 m is the diameter and L = 1:12 m the height). The measurements were conducted in the Rayleigh-number range 1011 < Ra < 1:35 1014 and Pr ' 0:8. For Ra = 1:35x1014, 2(z) could be described well by a logarithmic dependence on the vertical position z in a range of z 1 < z < z 2 with z 1 ' 70 and z 2 = 0:1L. Here L=(2Nu) is the thickness of a thin thermal sublayer adjacent to the horizontal plate where the heat flux (denoted by the Nusselt number Nu) is carried mostly by thermal diffusion. In the log layer, we found that the temperature spectra had a significant frequency range over which P(f) f with close to 1. As Ra decreased, increased so that the log layer became thinner. At Ra = 2:05 1011, z 2 < z 1 and therefore there was no range for a log layer. Correspondingly, the temperature spectrum near the horizontal plate did not have the f1 scaling form either
Lagrangian Raylaigh-Bénard convection
No full textUsing passive tracers as sensors, we obtain Lagrangian measurements of tracers position, velocity and temperature in Rayleigh-Bénard convection at Ra=10^7-10^9. We report on statistics of temperature, velocity, and heat transport (Nusselt number). We observe that the Nusselt number is characterized by a largely intermittent behavior, likely due to the interaction of temperature with turbulent velocity fluctuations
Photochemical behavior of some p-styryistilbenes and related compounds: Spectral properties and photoisomerization in solution and in solid state
No full textAuthor Posting. © The Authors (2006) This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in PHOTOCHEMISTRY AND PHOTOBIOLOGY, 82(6): 1645-1650. https://doi.org/10.1562/2006-01-17-RA-780ArticlePhotochemistry and Photobiology. 82(6): 1645-1650 (2006)journal articl
Can Studying Genetically Predisposed Individuals Inform Prevention Strategies for RA?
No full textRheumatoid arthritis (RA) is a prevalent autoimmune disorder in which complex genetic predisposition interacts with multiple environmental factors to precipitate chronic and progressive immune-mediated joint inflammation. Currently, in most affected individuals, ongoing suppression of the inflammation is required to prevent irreversible damage and functional loss. The delineation of a protracted preclinical period in which autoimmunity is initially established and then evolves to become pathogenic provides unprecedented opportunities for interventions that have the potential to prevent the onset of this lifelong disease. Clinical trials aimed at assessing the impact of specific prevention strategies require the identification of individuals who are at high risk of future RA development. Currently, these risk factors include a strong family history of RA, and the detection of circulating RA-associated autoantibodies, particularly anti-citrullinated protein antibodies (ACPA). Yet, even in such individuals, there remains considerable uncertainty about the likelihood and the timeframe for future disease development. Thus, individuals who are approached to participate in such clinical trials are left weighing the risks and benefits of the prevention measures, while having large gaps in our current understanding. To address this challenge, we have undertaken longitudinal studies of the family members of Indigenous North American RA patients, this population being known to have a high prevalence of RA, early age of onset, and familial clustering of cases. Our studies have indicated that the concepts of “risk” and “prevention” need to be communicated in a culturally relevant manner, and proposed prevention interventions need to have an appropriate balance of effectiveness, safety, convenience, and cultural acceptability. We have focused our proposed prevention studies on immunomodulatory/anti-inflammatory nutritional supplements that appear to strike such a complex balance
Aspect-ratio dependence of the transition to the ultimate state of turbulent Rayleigh-Bénard convection
No full textWe report on measurements of the ultimate-state transition in turbulent Rayleigh-B\'enard convection obtained in a large facility known as the ``Uboot of G\"ottingen" and using pressurized sulfur hexafluoride as the convecting fluid. We found that the transition occurs over a range of which becomes more narrow as increases, ranging from which is at most weakly dependent on and close to to which varies from about for to about for
Wall to wall optimal transport
No full textThe calculus of variations is employed to find steady divergence-free velocity fields that maximize transport of a tracer between two parallel walls held at fixed concentration for one of two constraints on flow strength: a fixed value of the kinetic energy or a fixed value of the enstrophy (the mean square rate of strain in this situation). The optimizing flows realize upper limits on convective transport in this scenario. We interpret the results in the context of buoyancy-driven Rayleigh–Bénard convection problems that satisfy the flow intensity constraints, enabling us to investigate how optimal transport scalings compare with upper bounds on Nu expressed as a function of the Rayleigh number Ra
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