Search results for "FORCE"
showing 10 items of 3423 documents
One-dimensional Mixed MHD Convection
2006
The parallel, fully developed flow of an electrically conducting fluid between plane parallel walls under the simultaneous influence of a driving pressure head, buoyancy, and magnetohydrodynamic (MHD) forces is studied. The fluid is assumed to be internally heated and the flow is modeled as one-dimensional and incompressible, while the Boussinesq approximation is adopted for the buoyancy terms. Analytical solutions are obtained for temperature, velocity and electrical potential under different electrical boundary conditions, forced to natural convection intensity ratios and values of the magnetic induction. Generalized working charts are presented which synthetically describe the system''s …
Enhancement of heat exchanger thermal hydraulic performance using aluminum foam
2018
Abstract This paper deals with an experimental study of a turbulent forced convection in a rectangular channel partly fitted with aluminum metallic foam blocks. Experiments were carried out on samples having a constant porosity of 93.8%, different grades of 5, 20 and 40 PPI, and three different height ratios of 0.6, 0.8 and 1. The blocks were arranged in a baffle like configuration. A constant heat flux of 2 W/cm2 was applied on the bottom wall of the test section, while air velocity was varied from 1 to 5 m·s−1. Temperatures of the wall along the flow direction as well as those of the inlet and outlet sections have been measured. Additionally, pressure drop measurements across the aluminum…
Coupled cluster calculations of interaction energies in benzene–fluorobenzene van der Waals complexes
2007
Benzene-fluorobenzene complexes are used as model systems to simulate the interactions of the SBB-HCAII protein-ligand complex. Using the second-order Moller-Plesset [MP2] and the coupled cluster singles and doubles including connected triple excitations models recently implemented with Cholesky decompositions we evaluate accurate interaction energies for several benzene-fluorobenzene van der Waals complexes. We consider edge-to-face interactions and compare the results to those from a recent MP2 study and to experimental findings. In contrast to experimental trends, we find that the interaction tends to decrease with increasing fluorination and conclude that benzene-fluorobenzene complexes…
Hip muscle function in patients with symptomatic femoroacetabular impingement
2014
Femoroacetabular impingement (FAI) is a pathomechanical process of the hip joint, which could lead to hip pain and functional disability. Aim of this thesis was to investigate hip muscle function in patients with a symptomatic FAI. Hip muscle function was first investigated before patients underwent any surgical treatment for managing FAI. It was shown that they present with reduced hip muscle strength (i.e., muscle weakness), probably due to hip muscle inhibition. Nevertheless, hip muscle weakness was not associated with exaggerated hip muscle fatigue. Hip muscle strength recovery was then evaluated in a series of patients after hip arthroscopy to treat FAI. These patients demonstrated a g…
Survey: Intrusion Detection Systems in Encrypted Traffic
2016
Intrusion detection system, IDS, traditionally inspects the payload information of packets. This approach is not valid in encrypted traffic as the payload information is not available. There are two approaches, with different detection capabilities, to overcome the challenges of encryption: traffic decryption or traffic analysis. This paper presents a comprehensive survey of the research related to the IDSs in encrypted traffic. The focus is on traffic analysis, which does not need traffic decryption. One of the major limitations of the surveyed researches is that most of them are concentrating in detecting the same limited type of attacks, such as brute force or scanning attacks. Both the …
Multiplicative cases from additive cases: Extension of Kolmogorov–Feller equation to parametric Poisson white noise processes
2007
Abstract In this paper the response of nonlinear systems driven by parametric Poissonian white noise is examined. As is well known, the response sample function or the response statistics of a system driven by external white noise processes is completely defined. Starting from the system driven by external white noise processes, when an invertible nonlinear transformation is applied, the transformed system in the new state variable is driven by a parametric type excitation. So this latter artificial system may be used as a tool to find out the proper solution to solve systems driven by parametric white noises. In fact, solving this new system, being the nonlinear transformation invertible, …
Physics and biophysics of solvent induced forces: hydrophobic interactions and context-dependent hydration
1998
Solvent induced forces (SIFs) among solutes derive from solvent structural modification due to solutes, and consequent thermodynamic drive towards minimization of related free energy costs. The role of SIFs in biomolecular conformation and function is appreciated by observing that typical SIF values fall within the 20–200 pN interval, and that proteins are stable by only a few kcal mol–1 (1 kcal mol–1 corresponds to 70 pN A). Here we study SIFs, in systems of increasing complexity, using Molecular Dynamics (MD) simulations which give time- and space-resolved details on the biologically significant scale of single protein residues and sidechains. Of particular biological relevance among our …
Effect of fatigue and gender on kinematics and ground reaction forces variables in recreational runners.
2017
The presence of fatigue has been shown to modify running biomechanics. Overall in terms of gender, women are at lower risk than men for sustaining running-related injuries, although it depends on the factors taken into account. One possible reason for these differences in the injury rate and location might be the dissimilar running patterns between men and women. The purpose of this study was to determine the effect of fatigue and gender on the kinematic and ground reaction forces (GRF) parameters in recreational runners. Fifty-seven participants (28 males and 29 females) had kinematic and GRF variables measured while running at speed of 3.3 m s−1 before and after a fatigue test protocol. T…
Freshman Engineering’ Reasoning Strategies When Answering FCI Questions: A Case Study
2020
Force Concept Inventory (FCI) is a questionnaire commonly used to assess students’ conceptual understanding of Newtonian Mechanics. We show that Cluster Analysis methods can be used to study student answers to FCI by finding their reasoning strategies on Newtonian Mechanics. Our analysis is performed to data obtained by a sample of freshman engineering students just at the beginning of their first General Physics course. The analysis takes into account the decomposition of the force concept into the conceptual dimensions suggested by test authors and successive researches. We identified groups of students with similar answering strategies, characterised by correct answers, as well as by non…
Motion and force analysis of slow-speed multi-trailer systems
2018
Comparing with the tractor-trailer systems for the road haulage, which must cope with some typical undesired trends, such as high-speed instability, over- or under-steering and off-tracking, the multi-trailer systems for the transport of luggage in the airports or in the railway stations, or for the transfer of goods in the warehouses, run at quite low speeds, but must manage to steer clear of the many obstacles encountered along their path. This type of vehicle is not subject to tire cornering phenomena, because the speed is just low and the wheels are generally stiff. Hence, the vehicle movement is in practice ruled by the non-holonomic rolling constraint of the wheels and by the steerin…