1,800 research outputs found
The impact of user-generated contents in the hotel industry
In many ways, the emergence of the Internet means consumers are now creating and spreading marketing information for various companies. Providers and consumers have become highly connected with the Internet environment. Therefore, user-generated-marketing information should be considered an important marketing tool in the hotel industry; Consumers can write reviews on travel websites or create personal blogs about their experiences. In addition, consumers post and upload pictures or movie files on the Internet, using advanced technologies. Consumers now can create and upload more visual materials, such as picture and video files, than in the past; Finally, this study focuses on encouraging hotel management to utilize user-generated content (UGC) as a valuable marketing tool, and concludes the hotel industry must build strong relationships with consumers who are interested in UGCs
Use of Adjacent Knot Data in Predicting Bending Strength of Dimension Lumber by X-Ray
In a previous study, the knot depth ratio (KDR) evaluation method was proposed to quantify the area of knots in a cross-section. That study reported that bending strength can be predicted by KDR analysis. However, the KDR model did not take into consideration the additional strength reduction caused by adjacent knots. It was found that the prediction of lumber strength was improved when adjacent knots were taken into consideration. Analysis using the KDRA (KDR adding knots) model revealed that the optimum cross-sectional interval, an input variable, is directly affected by knot size parallel to lumber length (KSPLL). KSPLL depends on the sawing method and log characteristics, and for species containing large knots, the cross-sectional interval is likely to be extremely wide. This can cause several adjacent small knots to be excluded from the analysis, requiring modification of the KDRA model algorithm. This modification resulted in improvement in the precision of the strength prediction, although the input variable of the cross-sectional interval was not used. The R2 values obtained using this method were 0.60 and 0.56 for Japanese larch and red pine, respectively
The Polarizable Charge Equilibration Model for Transition-Metal Elements
The polarizable charge equilibration (PQEq) method was developed to provide a simple but accurate description of the electrostatic interactions and polarization effects in materials. Previously, we optimized four parameters per element for the main group elements. Here, we extend this optimization to the 24 d-block transition-metal (TM) elements, columns 4ā11 of the periodic table including TiāCu, ZrāAg, and HfāAu. We validate the PQEq description for these elements by comparing to interaction energies computed by quantum mechanics (QM). Because many materials applications involving TM are for oxides and other compounds that formally oxidize the metal, we consider a variety of oxidation states in 24 different molecular clusters. In each case, we compare interaction energies and induced fields from QM and PQEq along various directions. We find that the original Ļ and J parameters (electronegativity and hardness) related to the ionization of the atom remain valid; however, we find that the atomic radius parameter needs to be close to the experimental ionic radii of the transition metals. This leads to a much higher spring constant to describe the atomic polarizability. We find that these optimized parameters for PQEq provide accurate interaction energies compared to QM with charge distributions that depend in a reasonable way on the coordination number and oxidation states of the transition metals. We expect that this description of the electrostatic interactions for TM will be useful in molecular dynamics simulations of inorganic and organometallic materials
The behaviour of stacking fault energy upon interstitial alloying
Stacking fault energy is one of key parameters for understanding the mechanical properties of face-centered cubic materials. It is well known that the plastic deformation mechanism is closely related to the size of stacking fault energy. Although alloying is a conventional method to modify the physical parameter, the underlying microscopic mechanisms are not yet clearly established. Here, we propose a simple model for determining the effect of interstitial alloying on the stacking fault energy. We derive a volumetric behaviour of stacking fault energy from the harmonic approximation to the energy-lattice curve and relate it to the contents of interstitials. The stacking fault energy is found to change linearly with the interstitial content in the usual low concentration domain. This is in good agreement with previously reported experimental and theoretical data.111Ysciescopu
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Atelectasis Induced by Thoracotomy Causes Lung Injury during Mechanical Ventilation in Endotoxemic Rats
Atelectasis can impair arterial oxygenation and decrease lung compliance. However, the effects of atelectasis on endotoxemic lungs during ventilation have not been well studied. We hypothesized that ventilation at low volumes below functional residual capacity (FRC) would accentuate lung injury in lipopolysaccharide (LPS)-pretreated rats. LPS-pretreated rats were ventilated with room air at 85 breaths/min for 2 hr at a tidal volume of 10 mL/kg with or without thoracotomy. Positive end-expiratory pressure (PEEP) was applied to restore FRC in the thoracotomy group. While LPS or thoracotomy alone did not cause significant injury, the combination of endotoxemia and thoracotomy caused significant hypoxemia and hypercapnia. The injury was observed along with a marked accumulation of inflammatory cells in the interstitium of the lungs, predominantly comprising neutrophils and mononuclear cells. Immunohistochemistry showed increased inducible nitric oxide synthase (iNOS) expression in mononuclear cells accumulated in the interstitium in the injury group. Pretreatment with PEEP or an iNOS inhibitor (1400 W) attenuated hypoxemia, hypercapnia, and the accumulation of inflammatory cells in the lung. In conclusion, the data suggest that atelectasis induced by thoracotomy causes lung injury during mechanical ventilation in endotoxemic rats through iNOS expression
Net loadādisplacement estimation in soilānailing pullout tests
Soil-nails are used to stabilise a soil mass by exploiting the resistance generated by the skin friction between the ground and grout and the tensile stiffness of the reinforcing material. A loadādisplacement curve is obtained from in situ pullout load tests performed by considering the elastic shear modulus and ultimate skin friction capacity between the soil and grout. This study determines the shear behaviour between the soils and grout analytically, especially the soil-dilation effect during shearing that is one of the main factors affecting the ultimate skin friction, even though this estimation is rather cumbersome. Many studies assume a full bond between the grout and the steel reinforcing bar, thus neglecting their relative displacement. In this study, the net loadādisplacement between the ground and grout is obtained by subtracting the nail elongation from the loadādisplacement of the pullout tests when estimating the shear displacement. Numerous field pullout tests are performed in this study under various ground conditions and through various construction methods. The dilatancy angles are estimated dependent on the soil type by comparing the net loadādisplacement curve obtained in the field with that obtained theoretically. </jats:p
The Polarizable Charge Equilibration Model for Transition-Metal Elements
The polarizable charge equilibration (PQEq) method was developed to provide a simple but accurate description of the electrostatic interactions and polarization effects in materials. Previously, we optimized four parameters per element for the main group elements. Here, we extend this optimization to the 24 d-block transition-metal (TM) elements, columns 4ā11 of the periodic table including TiāCu, ZrāAg, and HfāAu. We validate the PQEq description for these elements by comparing to interaction energies computed by quantum mechanics (QM). Because many materials applications involving TM are for oxides and other compounds that formally oxidize the metal, we consider a variety of oxidation states in 24 different molecular clusters. In each case, we compare interaction energies and induced fields from QM and PQEq along various directions. We find that the original Ļ and J parameters (electronegativity and hardness) related to the ionization of the atom remain valid; however, we find that the atomic radius parameter needs to be close to the experimental ionic radii of the transition metals. This leads to a much higher spring constant to describe the atomic polarizability. We find that these optimized parameters for PQEq provide accurate interaction energies compared to QM with charge distributions that depend in a reasonable way on the coordination number and oxidation states of the transition metals. We expect that this description of the electrostatic interactions for TM will be useful in molecular dynamics simulations of inorganic and organometallic materials
Synthesis of 2-Acylphenol and Flavene Derivatives from the Ruthenium-Catalyzed Oxidative C-H Acylation of Phenols with Aldehydes
The cationic ruthenium hydride complex [(C6H6)(PCy3)(CO)RuH]+BF4ā has been found to be an effective catalyst for the oxidative CāH coupling reaction of phenols with aldehydes to give 2-acylphenol compounds. The coupling of phenols with Ī±,Ī²-unsaturated aldehydes selectively gives the flavene derivatives. The catalytic method mediates direct oxidative CāH coupling of phenol and aldehyde substrates without using any metal oxidants or forming wasteful byproducts
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