Rich Side Research Articles

Measurement of marketing efficiency in the tourism sector of the municipality of Sucre

Tourism requires of big collective efforts to satisfy the growing needs of promotions and publicity, in order to accomplish and establishing volumes of tourist a lot more big tan the actual once. Sucre, one of the most important cities of the country, has tourism resources of real importance, that is because in this territory and since the colonial age, has been developed resources of historical, biotitic, architectonic one cultural type of great valve; this rich goose side to siole with the paleontology rich, as one of the most important scientists discoveries of the latest times, without men honing others that definitely make Sucre a touristic destiny of first class. Is because all of this, that is convenient to fulfill a study to the tourism providers, and see if the level of contributor that they, make are enough to develop inefficient touristic marketing program today.

The temperature dependence of the laminar burning velocity and superadiabatic flame temperature phenomenon for NH3/air flames

Combustion of ammonia (NH3) as a carbon-free alternative fuel has been recently widely studied, with vast majority of the burning velocity data obtained at room temperature. In the present study, the laminar burning velocity SL of NH3/air mixtures has been measured at unburnt gas temperature Tu from 298 K to 448 K, covering equivalence ratios from 0.85 to 1.25 and at 1 atm using the heat flux method. Kinetic simulations were made with five literature mechanisms developed for NH3 combustion, i.e., Nakamura et al., Otomo et al., San Diego, Okafor et al., and Mei et al. mechanisms, and the influence of radiation heat losses was considered. Using the obtained burning velocity data at different temperatures, the temperature dependence coefficients α in SLSL0=(TuTu0)α were derived, and compared with different models’ predictions. Further analyses of the temperature dependence of SL were carried out through examination of the overall activation energy, temperature and species profiles as well as the reaction paths, and a unique flame structure at the rich side of adiabatic NH3/air flames was found, which resembles ‘over-rich’ phenomena in hydrocarbon flames. At equivalence ratio larger than 1.1 ± 0.05, the NH3/air flames become so rich that (1) the NH2 radical overwhelms the H and OH radicals in maximum mole fraction; (2) after the flame front, H2O converts back to H2 with NO formed at the same time, causing the superadiabatic flame temperature phenomena, i.e. adiabatic flame temperature being lower than the maximum achieved in the flame. Moreover, local minimum NO concentration is found right after the over-rich NH3/air flame front, which may be helpful in reducing NO emissions from NH3 flames in practical applications.

Characterization of phases in the Zr–Nb–Fe ternary system at the Zr–Nb rich side of the phase diagram

The formation and transformation behavior of Zr–Nb–Fe ternary phases were studied in a ternary alloy with 25 at% Fe, and Zr-2.5 wt% Nb (also ∼2.5 at% Nb) pressure tube material that has a nominal Fe composition in the range ∼0.1 at% to 0.2 at%. For the ternary alloy, the evolution of the phase constitutions and corresponding lattice parameters from the as-cast to the annealed condition were measured by both X-ray and TEM diffraction, combined with crystallographic structural modeling. In the as-received material the two major phases are a Ti2Ni structured face centered cubic phase (FCC) and a hexagonal close-packed (HCP) C14 Laves phase. The alloy also contained a small fraction of metastable βNb/Zr phase containing a low concentration of Fe (∼1 at%). In addition to the aforementioned ZrNbFe phases, heat-treatment of the ternary alloy at temperatures below the ZrNb monotectoid temperature (∼580 °C and 500 °C) resulted in decomposition of the meta-stable βNb/Zr phase into HCP precipitates and BCC βNb precipitates. These precipitates were different from the as-received bulk HCP phase in composition but had similar lattice parameters, and showed similar electron diffraction patterns to the majority bulk HCP phase. A compositional analysis using known standards showed that the best stoichiometry assignment for the bulk HCP phase and the equilibrium phases that formed from decomposition of the metastable βNb/Zr phase is Nb(Zr,Fe)2. The HCP phase variant produced during heating below the monotectoid temperature was also produced upon heating of the Zr-2.5Nb pressure tubing. Detailed analysis of the HCP phase formed from the decomposition of the βNb/Zr phase that is dilute in Fe shows that it has a polytype structure consisting of both FCC and HCP structures.

A neural multi-context modeling framework for personalized attraction recommendation

In attraction recommendation scenarios, how to model multifaceted tourism contexts so as to accurately learn tourist preferences and attraction tourism features is a keystone of generating personalized recommendations. However, most of existing works generally focused on modeling spatiotemporal contexts of historical travel trajectories to learn tourists’ preferences, while neglected rich heterogeneous tourism side information, i.e., personal tourism constraints of tourists and tourism attributes of attractions. To this end, we propose a Neural Multi-context Modeling Framework (NMMF) to learn tourism feature representations of tourists and attractions by modeling multiple tourism contexts. Initially, we leverage a travel knowledge graph and massive original travelogues to construct the tourism attribute context of attractions and the travel trajectory context of tourists. Then, we design two context embedding models, named TKG2vec and Traj2vec, to model two kinds of context respectively. Both models learn feature vectors of tourist and attraction in contexts by elaborating neural networks to project each tourist and attraction into a uniform latent feature space. Finally, our framework integrates feature vectors derived from two models to acquire complete feature representations of tourists and attractions, and recommends personalized attractions by calculating the similarity between tourist and candidate attractions in the latent space. Experimental results on a real-world tourism dataset demonstrate our framework outperforms state-of-the-art methods in two personalized attraction recommendation tasks.

High antimicrobial photodynamic activity of photosensitizer encapsulated dual-functional metallocatanionic vesicles against drug-resistant bacteria S. aureus.

Developments in the field of photodynamic therapy (PDT) are being made by investigating appropriate photosensitizers (PSs) and enhancing the penetration effect of light by developing new nano-carriers. So, to boost the PDT effect, in the present work, new metallocatanionic vesicles were fabricated by a convenient, efficient, green and inexpensive method to encapsulate PSs and evaluate their antimicrobial PDT against the drug-resistant bacterium Staphylococcus aureus. They were prepared from a combination of a double-chained copper-based cationic metallosurfactant (CuCPCII) and an anionic surfactant sodium bis(2-ethylhexyl)sulfosuccinate (Aerosol OT or AOT). The surface charge, structure and ability to encapsulate oppositely charged photosensitizers are some crucial factors that need to be controlled for their effective utilization in PDT. In this approach, two of the fractions, one each from a cationic rich and anionic rich side, were selected to encapsulate cationic (methylene blue; MB) and anionic (rose bengal (RB)) PSs after characterization by SAXS, AFM, FESEM, DLS, and zeta-potential, and conductivity measurements. Afterwards, PDT was performed on S. aureus (a multidrug-resistant bacterium) by the colony forming unit (CFU) method using PS encapsulated metallocatanionic vesicles that demonstrated high bactericidal activity by using visible light (532 nm) and facilitated the generation of singlet oxygen. The singlet oxygen generation capability of both the PSs was enhanced under irradiation when encapsulated in metallocatanionic vesicles because the presence of metal accelerated the intersystem crossing of triplet oxygen to singlet oxygen. Furthermore, these studies reveal that the metallocatanionic vesicles have dual functionality i.e. encapsulate PSs and even show dark toxicity against S. aureus. To study the killing of S. aureus, bacterial DNA was extracted and its interactions and conformational changes in the presence of metallocatanionic vesicles were analyzed via., UV-Visible, and circular dichroism (CD) spectroscopy. Comet assay (single-cell gel-electrophoresis) demonstrated the DNA damage after PDT treatment in an individual cell. The bacterial DNA damage was more with the metallosurfactant rich 70 : 30 fraction than with the 30 : 70 fraction, in combination with RB under irradiation. This work provides a new metal hybrid smart material that possesses dual functionality and is prepared by an easy, economical and feasible procedure which resulted in enhanced PDT against a drug-resistant bacterium, thus, providing an alternative for antibacterial therapy.

MRP2Rec: Exploring Multiple-Step Relation Path Semantics for Knowledge Graph-Based Recommendations

Knowledge graphs (KGs) have been proven to be effective for improving the performance of recommender systems. KGs can store rich side information and relieve the data sparsity problem. There are many linked attributes between entity pairs (e.g., items and users) in KGs, which can be called multiple-step relation paths. Existing methods do not sufficiently exploit the information encoded in KGs. In this paper, we propose MRP2Rec to explore various semantic relations in multiple-step relation paths to improve recommendation performance. The knowledge representation learning approach is used in our method to learn and represent multiple-step relation paths, and they are further utilized to generate prediction lists by inner products in top-K recommendations. Experiments on two real-world datasets demonstrate that our model achieves higher performance compared with many state-of-the-art baselines.

Effects of channel length on propagation behaviors of non-premixed H2-air flames in Y-shaped micro combustors

In the present study, dynamics of non-premixed hydrogen-air flames in two Y-shaped cylindrical micro combustors of different horizontal channel lengths (L = 100 and 200 mm) were experimentally compared. The inner diameters of the micro-combustors are 2 mm. Unburned mixture was ignited by heating the near-exit wall with a butane torch. The results show that six and three flame propagation modes in the 200-mm and 100-mm micro-combustors were observed, respectively. Moreover, it is found that the flame oscillation duration is much longer with a larger noise intensity in the 200-mm micro-combustor. As a result, the mean propagation speed under L = 100 mm is much larger. In addition, the edge flame is longer on the lean side under L = 100 mm and almost identical on the rich side for the two combustors. Furthermore, the luminosity of edge flame in the 100-mm micro-combustor is much brighter. Numerical analysis reveals that the deflection of propagating flame in the Y-shaped micro-combustor is determined by the stoichiometric line. In summary, the short combustor has a smaller heat loss ratio and a stronger flame-wall thermal coupling, which can enhance the combustion intensity and increase the flame propagation speed.

Superdeformation in Pb isotopes with large neutron excess

Covariant Density Functional theory (CDFT) is used to investigate superdeformation in Pb isotopes on the neutron rich side of the periodic table. Energy surfaces and deformation parameters in this region are calculated by solving the constrained Relativistic Hartree Bogoliubov (RHB) equations. We use the parameter set DDME2, which has an explicit density dependence as well in the isoscalar as in the isovector channel together with the finite range pairing force DIS of Gogny. With increasing neutron number we find a characteristic pattern for superdeformed minima in these nuclei.

Development of a CALPHAD Thermodynamic Database for Pu-U-Fe-Ga Alloys

The interaction of actinides and actinide alloys such as the δ-stabilized Pu-Ga alloy with iron is of interest to understand the impurity effects on phase stability. A newly developed and self-consistent CALPHAD thermodynamic database is presented which covers the elements: Pu, U, Fe, Ga across their whole composition and temperature ranges. The phase diagram and thermodynamic properties of plutonium-iron (Pu-Fe) and uranium-iron (U-Fe) systems are successfully reassessed, with emphasis on the actinide rich side. Density functional theory (DFT) calculations are performed to validate the stability of the stoichiometric (Pu,U)6Fe and (Pu,U)Fe2 compounds by computing their formation enthalpies. These data are combined to construct the Pu-U-Fe ternary phase diagram. The thermodynamic assessment of Fe-Ga is presented for the first time and application to the quaternary Pu-U-Fe-Ga system is discussed.

Determination of heat treatment parameters by experiments and CALPHAD for precipitate hardening of Cr-Alloys with Si, Ge and Mo

Binary Cr–Si alloys as well as ternary Cr–Si-Ge and Cr–Si–Mo-systems on the Cr rich side of the phase diagram are examined at 1050 °C and 1350 °C regarding the maximum solubility in the bcc solid solution matrix and the A15-phase volume fraction. SEM, EDS and image analysis measurements showed, that the addition of 2 at.% Ge has the same effect on the A15-phase formation as Si but leads to a coarser microstructure. The addition of 2 at.% Mo leads to a decreased A15-phase volume fraction but a small-sized precipitate distribution. The maximum solubility of Si in the binary Cr–Si system is still not clear and has to be verified in further examinations. Thermo-Calc calculations showed, that a reduction of Si content and the addition of Ge and Mo is beneficial for an increase in the process window for solution heat treatment and a decrease of the solvus temperature.

Measurement of laminar burning velocity of high performance alternative aviation fuels

An experimental study was conducted on the measurement of the laminar burning velocity of alternative aviation fuels, in order to assess the feasibility of using the newly developed fuels in aviation applications. Two kinds of high performance hydrocarbon fuels (HPF-1 and 2), having higher density but moderate viscosity as compared with existing conventional aviation fuels, were created, and a Bunsen burner was manufactured to measure their laminar burning velocities at an elevated temperature of 550 K and atmospheric pressure. The measured laminar burning velocity of HPF-1 and 2 at the preheating temperature shows that the peak burning velocity of HPF-1 is approximately 125 cm/s, which is very close to that of the reference fuel (RF) and higher than Jet A-1, while the maximum laminar burning velocity of HPF-2 is shown to be approximately 130 cm/s, which is slightly higher (5–6 cm/s) than those of HPF-1 and RF. Compared with RF and Jet A-1, furthermore, the laminar burning velocity curves of HPFs shift to the fuel-rich side, with a corresponding decrease in the burning velocity on the lean side and an increase on the rich side. Therefore, the equivalence ratio where the laminar burning velocity reaches maximum (Φmax) increases slightly for the HPFs; Φmax for Jet A-1 and RF are around 1.07 and 1.08, respectively, while those for HPF-1 and 2 are 1.12 and 1.14, respectively. These fundamental data can be used to develop and validate combustion models to enable quantitative performance predictions in engine design for the newly developed fuels.

Experimental study on the explosion characteristics of methylcyclohexane/toluene-air mixtures with methanol addition at elevated temperatures

Explosion characteristics of methylcyclohexane (MCH)-methanol- and toluene-methanol-air mixtures were investigated in a closed vessel at 0.1MPa covering wide blending ratio range. The explosion hazard was evaluated by determining important explosion parameters. Comparisons were made between MCH- and toluene-air mixtures and the effects of methanol addition were identified. Results show that MCH-air yields approximate peak explosion pressure with toluene-air mixture but higher maximum rate of pressure rise. For the blend-air mixtures, the methanol addition exerts limited effect on the peak explosion pressure. For the maximum rate of pressure rise, the 20% methanol addition results in slight variation and further addition of methanol causes significant increase tendency. Regarding explosion phase parameters, toluene-air has longer explosion delay and burn period than MCH-air does. At the lean mixture side, the methanol addition generates slight decreases of explosion delay and burn period. At the rich mixture side, 20% methanol addition slightly extends the explosion delay and yields limited effect on the burn period. Further addition of methanol could significantly decrease the explosion delay and burn period simultaneously. Finally, the deflagration index was exponentially correlated with the explosion delay or burn period with the fitting constants listed.

Damping performance of alumina and zirconia-based plasma sprayed coatings

ABSTRACT Alumina and zirconia coatings along with three combinations of alumina-zirconia (AZ) composite coatings are deposited on AISI304 by atmospheric plasma spraying (APS) technique. The AZ coatings are developed on the alumina rich side by varying zirconia content (e.g. 5%, 15% and 25%). To investigate the phases , X-ray diffraction technique is utilized. Scanning electron microscopy technique is used to study the microstructures. The damping behaviors are studied by dynamic mechanical analyzer (DMA). It is observed that, zirconia has much better damping property than alumina and the damping capacity (i.e. tan δ) is increased with an increase in zirconia content in AZ coatings. However, it is interesting to note that the variation of complex modulus of AZ coating showed opposite trend as it showed in damping capacity. The damping capacities of all deposited coatings show a stable response over time and frequencies up to 60 Hz.

Suppression of the Shastry-Sutherland phase driven by electronic concentration reduction in magnetically frustratedCe2.15Pd1.95(Sn1−yIny)0.9alloys

Shastry-Sutherland lattice was observed as alternative ground state in Rare Earth intermetallic with Mo$_2$B$_2$Fe and U$_2$Pt$_2$Sn anisotropic structures where magnetic frustration is favored. In the case of Ce$_2$Pd$_2$Sn, it was shown that such phase can be suppressed by the application of magnetic field and, in this work, its stability is studied as a function of the electronic concentration by doping the Sn(4+) lattice with In(3+) atoms. Magnetic and specific heat measurements show that around 50\% substitution the Shastry Sutherland lattice vanishes in a critical point. This result confirms the strong dependence of that phase on the electron density because a recent investigation on the Pd rich solid solution Ce$_{2+\epsilon}$Pd$_{2-\epsilon}$In$_{1-x}$Sn$_x$ (with $\epsilon < 0$) demonstrates that atomic disorder dominates the phase diagram at intermediate Sn/In concentration inhibiting magnetic frustration effects. In the alloys investigated in this work, the $\epsilon >0$ character stabilizes the ferromagnetic ground state all along the concentration, allowing the Shastry Sutherland lattice formation on the Sn rich side.

Interdiffusion study of the topologically closed packed μ phase and the phase boundary compositions in the Fe–Mo system

Fe/Mo bulk diffusion couples are annealed at 1050–1200 °C to study the growth and diffusion behaviour of μ phase in the Fe–Mo system. Parabolic growth constants and integrated interdiffusion coefficients are determined in the μ phase. The activation energies for the growth of μ phase and for the integrated interdiffusion coefficients are estimated as 228±22 and 733±10 kJ/mol, respectively. The relatively high activation energy for interdiffusion in μ phase, determined at high homologous temperature of 0.8–0.9, indicates that μ phase grows by lattice diffusion. Phase boundary compositions, measured by EPMA, indicates the homogeneity range of μ phase to be ~3 at.% higher towards the Fe–rich side (i.e., 36 at.% Mo) as compared to the reported composition of 39–44 at.% Mo in the phase diagram.

Structure and growth behavior of intermediate phase in Cu–Zr diffusion couple heated by pulse current

In this research, Cu–Zr diffusion couples were heated by pulse current and a conventional heating method, respectively. Comparative analyses on the diffusion behavior of Zr and Cu atoms, interfacial structure and growth behavior of diffusion reaction area were carried out. The results show that applying pulse current can accelerate the migration rate of atoms, promote the diffusion of Zr atoms to the copper substrate in a short holding time, achieve a metallurgical bonding and form a continuous, dense reaction layered structure with a two-layer interface. The pulse current heating can induce the formation of lamellar ZrCu phase in the copper substrate interface. After holding for a relatively short period of time, a large number of Zr atoms crossed through the ZrCu phase, formed ZrCu3 phase in the copper rich phase side and grew gradually along the depth direction of copper substrate. Meanwhile, the growth rate of ZrCu phase was relatively slow due to the weak diffusion ability of Cu atom to in zirconium matrix.

The spillover effects of attentional learning on value-based choice

What role does attention play in decision-making? Prior research has demonstrated a link between visual attention and value-based choice, but the direction of causality is still unclear. Here we aimed to demonstrate that attention has a causal influence on choice. We tested whether spatially biasing attention in a visual search task would produce choice biases in a later choice task. We ran four experiments where the search target was more likely to appear on one “rich” side of the screen. In the subsequent choice tasks, participants were more likely to choose items appearing on the rich side and the average choice bias depended on how well participants learned the regularity in the search task. Additionally, eye-tracking data revealed a first-fixation bias toward the rich side, which in turn influenced choices. Taken together, these results provide novel support for a causal effect of attention on choice.

When two is enough: On the origin of diverse crystal structures and physical properties in the Fe-Ge system

The Fe-Ge system resides among the richest binary intermetallic systems both in terms of the number of intermediate phases and diversity of crystal structures and magnetic properties. Although crystal structures of the Fe-Ge binary phases are different, they are closely related to each other with an evolution of Ge polyhedra being the cornerstone that weld them together. Upon transition to the Ge rich side the initial Ge polyhedron gradually loses vertex Fe atoms in a diverse manner creating a variety of different iron frameworks from 3-dimensional ones to practically isolated Fe atoms. This, along with strong electron correlations provided by Fe-Fe and Fe-Ge interactions, leads to a broadness of physical properties varying from metallic ferromagnets to metallic antiferromagnets with complex magnetic structures and ultimately to a non-magnetic insulator. This minireview surveys the crystal and electronic structures of binary compounds of the Fe–Ge system and relationships with their transport and magnetic properties.

TCFACO: Trust-aware collaborative filtering method based on ant colony optimization

Recommender systems (RSs) aim to help users to find relevant information based on their preferences instead of searching through extensive volume of information using search engines. Accurate prediction of unknown ratings is one of the key challenges in the analysis of RSs. Collaborative Filtering (CF) is a well-known recommendation method that estimates missing ratings by employing a set of similar users to the target user. An outstanding topic in CF is picking out an appropriate set of users and using them in the rating prediction process. In this paper, a novel CF method is proposed to predict missing ratings accurately. The proposed method called TCFACO uses trust statements as a rich side information with Ant Colony Optimization (ACO) method. TCFACO consists of three main steps. In the first step, users are ranked considering available rating values and social trust relationships. Then, in the second step, the ACO method is utilized to assign proper weight values to users to show how they are similar to the target user. A set of top similar users is filter out in the third step to be used in predicting unknown ratings for the target user. In other words, to speed up identifying similar users, the proposed method first filters out a majority part of dissimilar users and then runs the ACO on only a reduced set of users to weight them. Several experiments were performed on three real-world datasets to evaluate the effectiveness of the proposed method and the results show that the proposed method performs better than the state-of-the-art methods.

Unusual temperature dependence of the solid-liquid interfacial free energy in the Cu-Zr system

The solid-liquid portion of the equilibrium phase diagram at the Cu rich side of a Finnis-Sinclair description of Cu-Zr was determined by a combination of molecular dynamics and semi-grand canonical Monte Carlo simulations and the model system was found to be in very good agreement with experiment. Molecular dynamics simulations and the capillary fluctuation method were used to compute the solid-liquid interfacial free energy, γ, and its anisotropy as a function of undercooling. Unlike the case of pure metals and in contrast to most previous atomistic studies in alloy systems, γ was found to increase with decreasing temperature and the increase is quite pronounced. To verify the unusual results, the excess energy and number of Zr atoms were computed for the [1 0 0] interface and from the excess thermodynamic quantities γ was obtained through a thermodynamic integration. The results of the two approaches for computing γ are in agreement to within the statistical uncertainties. The implications of the temperature behavior of γ is discussed in terms of crystal nucleation from the melt and glass formation.