THE EFFECTIVENESS OF LEARNING VOCABULARY THROUGH GAMES IN COMPARISON WITH THAT IN TRADITIONAL TECHNIQUE

This research was conducted to compare the impacts of two vocabulary teaching techniques (through games and the traditional technique) on English vocabulary learning of a low proficiency group of the first students at Thanh Hoa University of Culture, Sports and Tourism. 60 subjects were divided in to two groups (an experimental group and a control group) comprising 30 students within the age range of 18-20. The subjects were assigned to two almost homogeneous groups, based on their scores on a general test which had been implemented before. All the students had the same level of English knowledge. The teacher as well as teaching materials was the same for the two groups. In the experimental group, the students were learned new words by memorizing word lists associated with their Vietnamese meanings. In the control group, the students were taught to learn new words through games. The data were collected from the similar tests of the pretest and posttest, which were administered to both groups. Each of them consisted of 40 multiple-choice items of vocabulary and a small post survey at the end of the sessions. The results of the study revealed that the students in the control group outperformed those in the experimental group. Based on the findings of the study , it can be concluded that games enhanced vocabulary development of the learners better than rote memorization of word-lists

Adaptive cooperative communications for enhancing QoS in vehicular networks

In a vehicular network with high mobility, it is challenging to ensure reliable and efficient connections among vehicles and between vehicles and roadside communication units (or infrastructure) such as base stations or WiFi hot spots. In this paper, we propose a method that utilizes cooperative communications for a combined vehicle-to-infrastructure (V2I) with vehicle-to-vehicle (V2V) approach to improving quality of service (QoS) across the vehicular network. In this approach, we have obtained the closed-form expressions of key QoS performances such as outage probability, throughput, energy efficiency, packet delivery ratio, packet loss rate and average end-to-end-delay for different investigated transmission schemes. These performances can be optimized by adaptively selecting appropriate transmission schemes and, as a results, good trade-offs between system reliability and efficiency can also be achieved under various environmental conditions

Semi-Continuous and Continuous Anaerobic Treatment of Palm Oil Mill Effluent for the Production of Organic Acids and Polyhydroxyalkanoates

The aim of this study was to improve organic acids production in semi and continuous anaerobic treatment of Palm Oil Mill Effluent (POME) using a locally fabricated 50 L Continuously Stirred Tank Reactor (CSTR). The organic acids obtained were then used for polyhydroxyalkanoate (PHA) production by Ralstonia eutropha ATCC 17699 in a 2 L bioreactor. The conditions used in the anaerobic treatment were controlled pH 6.5, sludge to POME ratio at 1:1 and Hydraulic Retention Time (HRT) of 4 days. The organic acids obtained were about 15 g L-1 at steady state for both treatments and the organic acids yield (based on BOD) was 58.3%. The selected organic acids obtained were acetic (51.5%), propionic (27%) and butyric (21.5%) acid. The recovery of the clarified and concentrated organic acids from the treated POME was made using a two-steps evaporation process. The clarified organic acids (distillate) obtained were comprising of 44.6, 20.1 and 22.5 g L-1 acetic, propionic and butyric acids, respectively with a recovery of 76%. The organic acids collected were then used for polyhydroxyalkanoates accumulation by Ralstonia eutropha ATCC 17699 using pH stat fed-batch fermentation under nitrogen limitation of C/N 40 in a 2 L fermenter. The highest PHA concentration of 11.4 g L-1 (>90% w/w) was achieved in this process

A Three-Flavor AdS/QCD Model with a Back-Reacted Geometry

A fully back-reaction geometry model of AdS/QCD including the strange quark is described. We find that with the inclusion of the strange quark the impact on the metric is very small and the final predictions are changed only negligibly.Comment: 10 pages, 2 figures; references revised, minor change for caption of fig

Critical point of QCD at finite T and \mu, lattice results for physical quark masses

A critical point (E) is expected in QCD on the temperature (T) versus baryonic chemical potential (\mu) plane. Using a recently proposed lattice method for \mu \neq 0 we study dynamical QCD with n_f=2+1 staggered quarks of physical masses on L_t=4 lattices. Our result for the critical point is T_E=162 \pm 2 MeV and \mu_E= 360 \pm 40 MeV. For the critical temperature at \mu=0 we obtained T_c=164 \pm 2 MeV. This work extends our previous study [Z. Fodor and S.D.Katz, JHEP 0203 (2002) 014] by two means. It decreases the light quark masses (m_{u,d}) by a factor of three down to their physical values. Furthermore, in order to approach the thermodynamical limit we increase our largest volume by a factor of three. As expected, decreasing m_{u,d} decreased \mu_E. Note, that the continuum extrapolation is still missingComment: 10 pages, 2 figure

An inverse model to determine the heat transfer coefficient and its evolution with time during solidification of light alloys

Infra-red probes linked to pyrometric chains and thermocouple arrays have been used to accurately determine both casting and die surface temperatures during the solidification of an aluminium A380 alloy and the magnesium alloy AZ91D. An inverse model was then used to accurately determine the heat flux densities and interfacial heat transfer coefficients and the rapid evolution of these values with time during high pressure die casting of these alloys

Study of 5.8 GHz Band-Stop Frequency Selective Surface (FSS)

This paper presents the study of 5.8 GHz frequency selective surface (FSS) acts as a band stop to eliminate unwanted radiation signal at 5.8GHz. The FSS was designed using computer simulation technology (CST) Microwave Studio software. The paper shows the comparison of square loop, octagon loop and hexagon loop of Band stop FSS (BSFSS) performance at 5.8 GHz. Besides, the BSFSS design using four different type of dielectric substrate such as FR-4, TLY-5, Roger RT5870 and Roger RT5880 were compared. The results obviously show that the Rogers RY5880 has the attenuation -44.72 dB.  The fabricated FSS were measured by using free space technique with two horn antennas connected to performance network analyzer (PNA). The measured and simulated results were compared. The results show that the square loop FSS structure have the better attenuation -26.76 dB (simulated) and -38.34 dB (measured) at 5.8 GHz

Three Flavour QCD from the Holographic Principle

Building on recent research into five-dimensional holographic models of QCD, we extend this work by including the strange quark with an SU(3)_L\times SU(3)_R gauge symmetry in the five-dimensional theory. In addition we deform the naive $AdS$ metric with a single parameter, thereby breaking the conformal symmetry at low energies. The vector and axial vector sectors are studied in detail and both the masses and decay constants are calculated with the additional parameters. It is shown that with a single extra degree of freedom, exceptional agreement with experimental results can be obtained in the light quark sector while the kaon sector is found to give around 10% agreement with lattice results. We propose some simple extensions to this work to be taken up in future research.Comment: 9 pages, 1 figure, references adde

The Chiral Model of Sakai-Sugimoto at Finite Baryon Density

In the context of holographic QCD we analyze Sakai-Sugimoto's chiral model at finite baryon density and zero temperature. The baryon number density is introduced through compact D4 wrapping S^4 at the tip of D8-\bar{D8}. Each baryon acts as a chiral point-like source distributed uniformly over R^3, and leads a non-vanishing U(1)_V potential on the brane. For fixed baryon charge density n_B we analyze the bulk energy density and pressure using the canonical formalism. The baryonic matter with point like sources is always in the spontaneously broken phase of chiral symmetry, whatever the density. The point-like nature of the sources and large N_c cause the matter to be repulsive as all baryon interactions are omega mediated. Through the induced DBI action on D8-\bar{D8}, we study the effects of the fixed baryon charge density n_B on the pion and vector meson masses and couplings. Issues related to vector dominance in matter in the context of holographic QCD are also discussed.Comment: V3: 39 pages, 16 figures, minor corrections, version to appear in JHEP. V2: references added, typos correcte

Interpolating between low and high energy QCD via a 5D Yang-Mills model

We describe the Goldstone bosons of massless QCD together with an infinite number of spin-1 mesons. The field content of the model is SU(Nf)xSU(Nf) Yang-Mills in a compact extra-dimension. Electroweak interactions reside on one brane. Breaking of chiral symmetry occurs due to the boundary conditions on the other brane, away from our world, and is therefore spontaneous. Our implementation of the holographic recipe maintains chiral symmetry explicit throughout. For intermediate energies, we extract resonance couplings. These satisfy sum rules due to the 5D nature of the model. These sum rules imply, when taking the high energy limit, that perturbative QCD constraints are satisfied. We also illustrate how the 5D model implies a definite prescription for handling infinite sums over 4D resonances. Taking the low energy limit, we recover the chiral expansion and the corresponding non-local order parameters. All local order parameters are introduced separately.Comment: Corresponds to published version, with some typos correcte