Abstract: As it is known, buoyancy and drag forces rule bubble's rise velocity in a liquid column. These forces are strongly dependent on fluid properties, gravity as well as equivalent's diameter. This study reports a set of bubble rising velocity experiments in a liquid column using water or glycerol. Several records of terminal velocity were obtained. The results show that bubble's rise terminal velocity is strongly dependent on dynamic viscosity effect. The data set allowed to have some terminal velocities data interval of 8.0 ? 32.9 cm/s with Reynolds number interval 1.3 -7490. The bubble's movement was recorded with a video camera. The main goal is to present an original set data and results that will be discussed based on two-phase flow's theory. It will also discussed, the prediction of terminal velocity of a single bubble in liquid, as well as the range of its applicability. In conclusion, this study presents general expressions for the determination of the terminal velocity of isolated gas bubbles of a Reynolds number range, when the fluid proprieties are known.
Abstract: Governments around the world are expending
considerable time and resources framing strategies and policies to
deliver energy security. The term 'energy security' has quietly
slipped into the energy lexicon without any meaningful discourse
about its meaning or assumptions. An examination of explicit and
inferred definitions finds that the concept is inherently slippery
because it is polysemic in nature having multiple dimensions and
taking on different specificities depending on the country (or
continent), timeframe or energy source to which it is applied. But
what does this mean for policymakers? Can traditional policy
approaches be used to address the problem of energy security or does
its- polysemic qualities mean that it should be treated as a 'wicked'
problem? To answer this question, the paper assesses energy security
against nine commonly cited characteristics of wicked policy
problems and finds strong evidence of 'wickedness'.
Abstract: Meshing is the process of discretizing problem
domain into many sub domains before the numerical calculation can
be performed. One of the most popular meshes among many types of meshes is tetrahedral mesh, due to their flexibility to fit into almost
any domain shape. In both 2D and 3D domains, triangular and tetrahedral meshes can be generated by using Delaunay triangulation.
The quality of mesh is an important factor in performing any Computational Fluid Dynamics (CFD) simulations as the results is
highly affected by the mesh quality. Many efforts had been done in
order to improve the quality of the mesh. The paper describes a mesh
generation routine which has been developed capable of generating
high quality tetrahedral cells in arbitrary complex geometry. A few
test cases in CFD problems are used for testing the mesh generator.
The result of the mesh is compared with the one generated by a
commercial software. The results show that no sliver exists for the
meshes generated, and the overall quality is acceptable since the percentage of the bad tetrahedral is relatively small. The boundary
recovery was also successfully done where all the missing faces are
rebuilt.
Abstract: This paper presents a numerical study on surface heat
transfer characteristics of laminar air flows in parallel-plate dimpled
channels. The two-dimensional numerical model is provided by
commercial code FLUENT and the results are obtained for channels
with symmetrically opposing hemi-cylindrical cavities onto both
walls for Reynolds number ranging from 1000 to 2500. The influence
of variations in relative depth of dimples (the ratio of cavity depth to
the cavity curvature diameter), the number of them and the thermophysical
properties of channel walls on heat transfer enhancement is
studied. The results are evident for existence of an optimum value for
the relative depth of dimples in which the largest wall heat flux and
average Nusselt number can be achieved. In addition, the results of
conjugation simulation indicate that the overall influence of the ratio
of wall thermal conductivity to the one of the fluid on heat transfer
rate is not much significant and can be ignored.
Abstract: Medical Decision Support Systems (MDSSs) are sophisticated, intelligent systems that can provide inference due to lack of information and uncertainty. In such systems, to model the uncertainty various soft computing methods such as Bayesian networks, rough sets, artificial neural networks, fuzzy logic, inductive logic programming and genetic algorithms and hybrid methods that formed from the combination of the few mentioned methods are used. In this study, symptom-disease relationships are presented by a framework which is modeled with a formal concept analysis and theory, as diseases, objects and attributes of symptoms. After a concept lattice is formed, Bayes theorem can be used to determine the relationships between attributes and objects. A discernibility relation that forms the base of the rough sets can be applied to attribute data sets in order to reduce attributes and decrease the complexity of computation.
Abstract: In this paper we consider the problem of distributed adaptive estimation in wireless sensor networks for two different observation noise conditions. In the first case, we assume that there are some sensors with high observation noise variance (noisy sensors) in the network. In the second case, different variance for observation noise is assumed among the sensors which is more close to real scenario. In both cases, an initial estimate of each sensor-s observation noise is obtained. For the first case, we show that when there are such sensors in the network, the performance of conventional distributed adaptive estimation algorithms such as incremental distributed least mean square (IDLMS) algorithm drastically decreases. In addition, detecting and ignoring these sensors leads to a better performance in a sense of estimation. In the next step, we propose a simple algorithm to detect theses noisy sensors and modify the IDLMS algorithm to deal with noisy sensors. For the second case, we propose a new algorithm in which the step-size parameter is adjusted for each sensor according to its observation noise variance. As the simulation results show, the proposed methods outperforms the IDLMS algorithm in the same condition.
Abstract: In this paper, Neuro-Fuzzy based Fuzzy Subtractive
Clustering Method (FSCM) and Self Tuning Fuzzy PD-like
Controller (STFPDC) were used to solve non-linearity and trajectory
problems of pitch AND yaw angles of Twin Rotor MIMO system
(TRMS). The control objective is to make the beams of TRMS reach
a desired position quickly and accurately. The proposed method
could achieve control objectives with simpler controller. To simplify
the complexity of STFPDC, ANFIS based FSCM was used to
simplify the controller and improve the response. The proposed
controllers could achieve satisfactory objectives under different input
signals. Simulation results under MATLAB/Simulink® proved the
improvement of response and superiority of simplified STFPDC on
Fuzzy Logic Controller (FLC).
Abstract: This article presents a numerical study of the doublediffusive
mixed convection in a vertical channel filled with porous
medium by using non-equilibrium model. The flow is assumed
fully developed, uni-directional and steady state. The controlling
parameters are thermal Rayleigh number (RaT ), Darcy number (Da),
Forchheimer number (F), buoyancy ratio (N), inter phase heat transfer
coefficient (H), and porosity scaled thermal conductivity ratio
(γ). The Brinkman-extended non-Darcy model is considered. The
governing equations are solved by spectral collocation method. The
main emphasize is given on flow profiles as well as heat and solute
transfer rates, when two diffusive components in terms of buoyancy
ratio are in favor (against) of each other and solid matrix and fluid
are thermally non-equilibrium. The results show that, for aiding flow
(RaT = 1000), the heat transfer rate of fluid (Nuf ) increases upto a
certain value of H, beyond that decreases smoothly and converges
to a constant, whereas in case of opposing flow (RaT = -1000),
the result is same for N = 0 and 1. The variation of Nuf in (N,
Nuf )-plane shows sinusoidal pattern for RaT = -1000. For both cases
(aiding and opposing) the flow destabilize on increasing N by inviting
point of inflection or flow separation on the velocity profile. Overall,
the buoyancy force have significant impact on the non-Darcy mixed
convection under LTNE conditions.
Abstract: Introduction: Visual performance is an important factor in sport excellence. Visual involvement in a sport varies according to environmental demands associated with that sport. These environmental demands are matched by a task specific motor response. The purpose of this study was to determine if sport specific exercises will improve the visual performance of male rugby players, in order to achieve maximal results on the sports field. Materials & Methods: Twenty six adult male rugby players, aged 16-22, were chosen as subjects. In order to evaluate the effect of sport specific exercises on visual skills, a pre-test - post-test experimental group design was adopted for the study. Results: Significant differences (p≤0.05) were seen in the focussing, tracking, vergence, sequencing, eye-hand coordination and visualisation components Discussion & Conclusions: Sport specific exercises improved visual skills in rugby players which may provide them with an advantage over their opponents. This study suggests that these training programs and participation in regular on-line EyeDrills sports vision exercises (www.eyedrills.co.za) aimed at improving the athlete-s visual coordination, concentration, focus, hand-eye co-ordination, anticipation and motor response should be incorpotated in the rugby players exercise regime.
Abstract: In this work, an attempt is made to design an optimal
wind/pv/diesel hybrid power system for a village of Ain Merane,
Chlef, Algeria, where the wind speed and solar radiation
measurements were made. The aim of this paper is the optimization
of a hybrid wind/solar/diesel system applied in term of technical and
economic feasibility by simulation using HOMER. A comparison
was made between the performance of wind/pv/diesel system and the
classic connecting system.
Abstract: The use of un-activated bentonite, and un-activated
bentonite blended with limestone for the treatment of acid mine
drainage (AMD) was investigated. Batch experiments were
conducted in a 5 L PVC reactor. Un-activated bentonite on its own
did not effectively neutralize and remove heavy metals from AMD.
The final pH obtained was below 4 and the metal removal efficiency
was below 50% for all the metals when bentonite solid loadings of 1,
5 and 10% were used. With un-activated bentonite (1%) blended with
1% limestone, the final pH obtained was approximately 7 and metal
removal efficiencies were greater than 60% for most of the metals.
The Langmuir isotherm gave the best fit for the experimental data
giving correlation coefficient (R2) very close to 1. Thus, it was
concluded that un-activated bentonite blended with limestone is
suitable for potential applications in removing heavy metals and
neutralizing AMD.
Abstract: The impact assessment in its various forms has
recently become a very important part of policy-making and
legislation in many different countries. Regulatory impact assessment
(RIA) is yet another set of analytical methods deployed in the
legislation of the European Union, of many developed countries as
well as in many developing ones such as Mexico, Malaysia and
Philippines. The aim of this paper is to provide a theoretical
background for economic models in regulatory impact assessment
and an overview of their application especially on the financial
market in the Czech Republic. We found out an inadequate
application of these models, what makes room for further research in
this field.
Abstract: This study investigated the climatic factors associated
with Influenza incidence in Nakhon Si Thammarat, Southern
Thailand. Climatic factors comprised of the amount of rainfall,
percent of rainy days, relative humidity, wind speed, maximum,
minimum temperatures and temperature difference. A multiple
stepwise regression technique was used to fit the statistical model.
The result showed that the temperature difference and percent of
rainy days were positively associated with Influenza incidence in
Nakhon Si Thammarat.
Abstract: A multiple-option analytical model for the evaluation of the energy performance and distribution of aerodynamic forces acting on a vertical-axis Darrieus wind turbine depending on both rotor architecture and operating conditions is presented. For this purpose, a numerical algorithm, capable of generating the desired rotor conformation depending on design geometric parameters, is coupled to a Single/Double-Disk Multiple-Streamtube Blade Element – Momentum code. Both single and double-disk configurations are analyzed and model predictions are compared to literature experimental data in order to test the capability of the code for predicting rotor performance. Effective airfoil characteristics based on local blade Reynolds number are obtained through interpolation of literature low-Reynolds airfoil databases. Some corrections are introduced inside the original model with the aim of simulating also the effects of blade dynamic stall, rotor streamtube expansion and blade finite aspect ratio, for which a new empirical relationship to better fit the experimental data is proposed. In order to predict also open field rotor operation, a freestream wind shear profile is implemented, reproducing the effect of atmospheric boundary layer.
Abstract: The top-heavy demographic of low birth-rate and longer lifespan is a growing social problem, and one of its expected effects will be a shortage of young workers and a growing reliance on a workforce of middle-aged and older people. However, the environment of today's industrial workplace is not particularly suited to middle-aged and older workers, one notable problem being temperature control. Higher temperatures can cause health problems such as heat stroke, and the number of cases increases sharply in people over 65. Moreover, in conditions above 33°C, older people can develop circulatory system disorders, and also have a higher chance of suffering a fatal heart attack. We therefore propose a new method for controlling temperature in the indoor workplace. In this study two different verification experiments were conducted, with the proposed temperature control method being tested in cargo containers and conventional houses. The method's effectiveness was apparent in measurements of temperature and electricity consumption
Abstract: Breast cancer is the most common malignancy in the
world among women. Many therapies have been designed to treat
this disease. Mamectomy, chemotherapy and radiotherapy are still
the main therapies of breast cancer. However, the results were
unsatisfactory and still far from the ideal treatment.
PM 701is a natural product, has anticancer activity. The bioactive
fraction PMF and subfraction PMFK had been isolated from PM701.
PM 701 and its fractions were proved to have a cytotoxic properties
against different cancer cell lines. This article is directed for the
further examination of lyophilized PM701 and its active fractions on
the growth of breast cancer cells (MCF-7). PM 701, PMF or PMFK
were adding to the cultural medium, where MCF-7 is incubated.
PM 701, PMF or PMFK were able to inhibit significantly the
proliferation of MCF-7 cells, Moreover these new agents were
proved to induce apoptosis of the breast cancer cells; through its
direct effect on the nuclei.
Abstract: Virtual Reality Modelling Language (VRML) is description language, which belongs to a field Window on World virtual reality system. The file, which is in VRML format, can be interpreted by VRML explorer in three-dimensional scene. VRML was created with aim to represent virtual reality on Internet easier. Development of 3D graphic is connected with Silicon Graphic Corporation. VRML 2.0 is the file format for describing interactive 3D scenes and objects. It can be used in collaboration with www, can be used for 3D complex representations creating of scenes, products or VR applications VRML 2.0 enables represent static and animated objects too. Interesting application of VRML is in area of manufacturing systems presentation.
Abstract: The purpose of this study was to examine a broader range of sport constraints perceived by young Koreans in Australia who may need to adjust to changing behavioral expectations due to the socio-cultural transitions. Regardless of gender, in terms of quantitative findings, the most important participation constraints within the seven categories were resources, access, interpersonal, affective, religious, socio-cultural, and physical in that order. The most important constraining items were a lack of time, access, information, adaptive skills, and parental and family support in that order. Qualitative research found young Korean’s participation constraints among three categories (time, parental control and interpersonal constraints). It is possible that different ethnic groups would be constrained by different factors; however, this is outside the scope of this study.
Abstract: In this research, several physical and chemical properties and mineral contents of Russion olive (Elaeagnus angustifolia L.) fruit grown in Turkey were determined. In the fruit, length, width, thickness, weight were determined as 2.866cm, 1.880cm, 1.870cm, 2.90g; total soluble solids and colour were determined as 13.14% and S33O60Y99, respectively. In the seed, mean length, width, thickness, and weight were found to be 2.420cm, 0.508cm, 0.503cm, and 0.38g, respectively. In the fruit, 28 minerals (K, P, Ca, Na, Mg, S, Pb, Ba, Ga, As, In, Ti, Fe, Mn, Zn, Cu, Co, B, Cd, Se, Li, Sr, Al, Ni, Ag, V, Cr, Bi) were analyzed and 19 minerals were present at detectable levels. Russion olive fruit was richest in potassium (10296.906ppm), Mg (762.314ppm), P (609.694ppm), Ca (547.647ppm), and Na (222.749ppm).
Abstract: In the present paper, we investigate a differential subordination
involving multiplier transformation related to a sector in the
open unit disk E = {z : |z| < 1}. As special cases to our main
result, certain sufficient conditions for strongly starlike and strongly
convex functions are obtained.