1,236 research outputs found
Dynamical Heterogeneities and Cooperative Motion in Smectic Liquid Crystals
Using simulations of hard rods in smectic-A states, we find non-gaussian
diffusion and heterogeneous dynamics due to the equilibrium periodic smectic
density profiles, which give rise to permanent barriers for layer-to-layer
diffusion. This relaxation behavior is surprisingly similar to that of
non-equilibrium supercooled liquids, although there the particles are trapped
in transient (instead of permanent) cages. Interestingly, we also find
stringlike clusters of up to 10 inter-layer rods exhibiting dynamic
cooperativity in this equilibrium state.Comment: 10 pages, 4 figure
Identification of nonlinear vibrating structures: Part I -- Formulation
A self-starting multistage, time-domain procedure is presented for the identification of nonlinear, multi-degree-of-freedom systems undergoing free oscillations or subjected to arbitrary direct force excitations and/or nonuniform support motions. Recursive least-squares parameter estimation methods combined with nonparametric identification techniques are used to represent, with sufficient accuracy, the identified system in a form that allows the convenient prediction of its transient response under excitations that differ from the test signals. The utility of this procedure is demonstrated in a companion paper
Identification of nonlinear vibrating structures: Part II -- Applications
A time-domain procedure for the identification of nonlinear vibrating structures, presented in a companion paper, is applied to a "calibration" problem which incorporates realistic test situations and nonlinear structural characteristics widely encountered in the applied mechanics field. The "data" set is analyzed to develop suitable, approximate nonlinear system representations. Subsequently, a "validation" test is conducted to demonstrate the range of validity of the method under discussion. It is shown that the procedure furnishes a convenient means for constructing reduced-order nonlinear nonparametric mathematical models of reasonably high fidelity in regard to reproducing the response of the test article under dynamic loads that differ from the identification test loads
Perkembangan Terkini Studi Hadis Di Indonesia
Diakui bahwa perkembangan studi hadis tidak berbanding lurus dengan percepatan bidang ilmu keislaman lainnya. Artikel ini mengkaji perkembangan mutakhir studi hadis di Indonesia. Penulis mengemukakan bahwa keterlambatan kajian Hadis di Indonesia berlangsung dalam kurun waktu yang panjang, mulai dari awal masuknya Islam sampai sekitar akhir abad ke-20. Fenomena kajian Hadis belakangan menunjukkan adanya perkembangan di Indonesia dan bahkan keadaan terkini, Hadis mengalami kemajuan yang pesat, baik dari aspek kuantitas, maupun kualitas. Penulis berargumen bahwa kemajuan tersebut dibuktikan dengan munculnya program studi Ilmu Hadis di PTKIN dan penelitian dan buku yang diterbitkan, tidak lagi bersifat konvensional, tetapi sudah menemukan terobosan-terobosan baru. Karena itu fenomena baru tentang pengkajian Hadis di Indonesia diproyeksikan memiliki prospek yang menjanjikan di masa mendatang
On the Effects of Droplet Loading on the Structure of Spray Jets
This paper uses advanced laser diagnostics to investigate the effects of droplet loading on the structure and mixing patterns of sprays in a non-reacting, turbulent jet. A nozzle designed at University of Sydney with the objective of studying spray flames has been used for producing a two phase flow in a co-flowing air stream with well defined boundary conditions. Varying the quantity of liquid injective will vary the number density of the droplets in the flow. The co-flowing air stream is seeded with a fixed concentration of nitric oxide, NO which will act as a conserved scalar. Laser induced fluorescence of NO is exploited to provide a direct quantitative measure of the mixture fraction. Radial profiles of the mean and the rms of mixture fraction has been collected at various axial positions in jets with different spray loadings. It is found that mixture fraction profiles are different from those measured in turbulent gaseous jets and increasing the droplet loading increases the mixture fraction of the jet due to evaporating droplets
Enhanced Heat Transfer from Arrays of Jets Impinging on Plates
Multiple jets of various shapes, orientation and configuration are used regularly in a wide range of engineering applications to provide heating or cooling with impingement on a plate being one of the most common configurations due to the improved heat transfer rates. Design optimization has largely relied on empirical correlations that are limited by the range over which they were originally generated. Computational Fluid Mechanics is now sufficiently advanced to be used as an alternative method for obtaining optimal designs. This project uses the commercial Fluent package to compute heat transfer from a bank of jets impinging on a plate. Results for a single jet are validated against experimental data. The use of advanced turbulence modeling and appropriate boundary layer formulations are key ingredients for obtaining reliable calculations. The heat transfer resulting form the use of multi-jet configurations will be discussed in the paper
Pengaruh Motivasi terhadap Minat Berinvestasi di Pasar Modal dengan Pemahaman Investasi dan Usia sebagai Variabel Moderate
This study purpose is to examined if knowledge investment and age afford to moderate the effect of motivation towards investment interest in stock market. Which is the motivation consist of subvariabel social, self appreciation dan self actuality. Population of this research are the real investor in Pekanbaru. Sampling method is used random sampling.Data collected method used questionnaire which is spreaded to 86 respondent of investor in Pekanbaru. The hypotesis is examined by multiple linier regression and moderated regression analysis (MRA). And this research has results. First, investment knowledge has afford to moderate the effect of social motivation towards investment interest. Second, age has afford to moderate the effect of social motivation towards investment interest in Stock Market
Evaluation of on-line pulse control for vibration suppression in flexible spacecraft
On-line pulse control for vibration suppression in a flexible spacecraft was evaluated. A continuous beam vs. a truss was modeled. A linear finite element model was used to determine the truss characteristics. Control issues outlined are ED pulse actuator development, pseudo pulse algorithm development, and large nonlinear simulation problems
Syrian Refugees and the Digital Passage to Europe: Smartphone Infrastructures and Affordances
This research examines the role of smartphones in refugees’ journeys. It traces the risks and possibilities afforded by smartphones for facilitating information, communication, and migration flows in the digital passage to Europe. For the Syrian and Iraqi refugee respondents in this France-based qualitative study, smartphones are lifelines, as important as water and food. They afford the planning, navigation, and documentation of journeys, enabling regular contact with family, friends, smugglers, and those who help them. However, refugees are simultaneously exposed to new forms of exploitation and surveillance with smartphones as migrations are financialised by smugglers and criminalized by European policies, and the digital passage is dependent on a contingent range of sociotechnical and material assemblages. Through an infrastructural lens, we capture the dialectical dynamics of opportunity and vulnerability, and the forms of resilience and solidarity, that arise as forced migration and digital connectivity coincide
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