Influence of lattice distortions in classical spin systems

We investigate a simple model of a frustrated classical spin chain coupled to adiabatic phonons under an external magnetic field. A thorough study of the magnetization properties is carried out both numerically and analytically. We show that already a moderate coupling with the lattice can stabilize a plateau at 1/3 of the saturation and discuss the deformation of the underlying lattice in this phase. We also study the transition to saturation where either a first or second order transition can occur, depending on the couplings strength.Comment: Submitted to Phys. Rev.

Influencia de los grupos estratégicos sobre el rendimiento empresarial: Un enfoque multinivel

One of the main research questions in the field of strategic management is why firms obtain different performance levels. This paper answers this question from the strategic groups approach. This paper analyses the linkage between strategic groups and firm performance offering a multilevel analysis about the relative importance of intergroup and intragroup performance differences based on the use of hierarchical linear models (HLMs). The results show that intragroup differences explain firm performance better than intergroup differences

Seeing the last part of a hitting movement is enough to adapt to a temporal delay.

Being able to see the object that you are aiming for is evidently useful for guiding the hand to a moving object. We examined to what extent seeing the moving hand also influences performance. Subjects tried to intercept moving targets while either instantaneous or delayed feedback about the moving hand was provided at certain times. After each attempt, subjects had to indicate whether they thought they had hit the target, had passed ahead of it, or had passed behind it. Providing visual feedback early in the movement enabled subjects to use visual information about the moving hand to correct their movements. Providing visual feedback when the moving hand passed the target helped them judge how they had performed. Performance was almost as good when visual feedback about the moving hand was provided only when the hand was passing the target as when it was provided throughout the movement. We conclude that seeing the temporal relationship between the hand and the target as the hand crosses the target's path is instrumental for adapting to a temporal delay

The effects of travelling reasons on social media resources and tourist expectations

Esta investigación tiene como objetivo examinar la relación de las fuentes del contenido generado por el usuario (UGC) en las redes sociales, que proviene generalmente de fuentes de lazos fuertes y fuentes de lazos débiles, en la generación de expectativas turísticas sobre los recursos básicos y los recursos o factores de apoyo de los destinos. También se analiza el efecto moderador de las razones para viajar en la relación de las fuentes UGC y las expectativas turísticas. Para esta investigación, se recogieron 375 encuestas. Los resultados señalan que las razones o motivos del viaje son un factor importante a considerar en la generación de las expectativas turísticas, y en nuestro caso, el UGC que provenía de las fuentes de lazos débiles influyen de manera significativa en la generación de expectativas del turista cuando viaja por motivos de trabajo.This research aims to examine the relationship of user generated content (UGC) sources in social media which is provided by strong-tie sources and weak-tie sources on tourist expectations on core resources and factor supporting of the destinations, and also analyze the moderate effect of the reasons of travelling on the relationship of UGC sources and tourist expectations. 375 samples were collected. The results demonstrate that travelling reasons is an important factor to consider about the origin of tourist expectations. The UGC that was provided by weak-tie source has influence on tourist expectations when they travel with business reason

Use of nanofiltration membrane technology for ceramic industry wastewater treatment

A study has been undertaken of an advanced wastewater treatment approach using polymer nanofiltration membranes, in an attempt to obtain water of sufficient quality to allow it to be reused in the same production process or, alternatively, to be discharged without any problems. The study has initially focused on the removal of organic matter (reduction of COD) and the most representative ions present in the wastewater, such as Na+ , Mg2+, Cl- , and SO4 2- . In a first part of the study, with a view to optimising the experimental phase, a simulation has been performed of the nanofiltration process using the NanoFlux software. Among other things, the simulation allows the most suitable membranes to be selected as a function of the permeate flow rate and desired level of retention in the substances to be removed. The subsequent experimentation was carried out in a laboratory tangential filtration system that works with flat membranes. It was found that retention values of about 90% were obtained for the studied substances, with a good permeate flow rate, using low operating pressures. These results demonstrate the feasibility of the studied technology and its potential as a treatment for improving ceramic industry wastewater qualit

Reducing Shower Duration in Tourist Accommodations: A Covert True Experiment of Continuous Real-Time Eco-Feedback and Persuasive Messaging

This study inductively applies the Feedback Intervention Theory by empirically demonstrating the effectiveness of continuous, real-time eco-feedback and its interaction with motivational factors in modifying showering behavior. We conducted a covert true experiment across six tourist accommodations in Denmark, Spain, and the UK, where we deployed smart technology, in the form of a timer to provide the eco-feedback, coupled with persuasive messages. Data from over 17,500 showers showed that continuous, real-time eco-feedback reduced water runtime by 25.79% (CI = 8.24%; 39.98%). When the eco-feedback was paired with the most effective message—priming pro-environmental values and requiring a high effort to comply—water runtime was reduced by 23.55% (CI = 17.53%; 29.13%). The study’s robust experimental design, and its emphasis on actual behavior measurement, highlight the potential of smart technology to facilitate resource conservation

Multidimensional perspective of perceived value in industrial clusters

Purpose – This paper aims to demonstrate that aspects of a rational or functional character and aspects of an emotional and social nature condition the perceived value of the exchange relationships among firms in an industrial cluster. Design/methodology/approach: – The research uses structural equation models (SEM) to test the models and applies the maximum likelihood estimation method in all the causal models obtained in the course of the data analysis. Findings – The results obtained support the hypotheses put forward, and in particular the importance of emotional and social values in industrial relations. Research limitations/implications – Recent advances in consumer and services marketing consider that perceived value and satisfaction are central to explaining customer loyalty. However, very few studies in B2B explain the multidimensionality of perceived value. For this purpose, the authors test their working hypotheses in the Spanish ceramic tiles cluster. Specifically, they analyze the relationships between manufacturers and a supplier of frits, enamels and ceramic colors and related services. Practical implications – An empirical study demonstrates that experience and interpersonal relationships are more important than price and switching costs in an industrial cluster context. The empirical study and the results provide evidence for managers: the critical influence of the emotional and social values perceived by the customer on his level of satisfaction and on the achievement of final loyalty. Originality/value – The paper highlights the importance of the most intangible dimensions of value for the relations between companies in an industrial cluste

Prediction and final temporal errors are used for trial-to-trial motor corrections

Many daily life situations (e.g. dodging an approaching object or hitting a moving target) require people to correct planning of future movements based on previous temporal errors. However, the actual temporal error can be difficult to perceive: imagine a baseball batter that swings and misses a fastball. Here we show that in such situations people can use an internal error signal to make corrections in the next trial. This signal is based on the discrepancy between the actual and the planned action onset time: the prediction error. In this study, we used three interception tasks: reaching movements, saccadic eye movements and a button press that released a cursor moving ballistically for a fixed time. We found that action onset depended on the previous temporal error in the arm movement experiment only and not in the saccadic and button press experiments. However, this dependency was modulated by the movement time: faster arm movements depended less on the previous actual temporal error. An analysis using a Kalman filter confirmed that people used the prediction error rather than the previous temporal error for trial-by-trial corrections in fast arm movements, saccades and button press

Impact of Controlling the Site Distribution of Al Atoms on Catalytic Properties in Ferrierite-Type Zeolites

Zeolites with the ferrierite (FER) topology are synthesized using a combination of tetramethylammonium (TMA) cations with differently sized cyclic amines (pyrrolidine (Pyr), hexamethyleneimine (HMI), and 1,4- diazabicyclo[2.2.2]octane (DAB)). Using these organic structure-directing agents (SDAs), low Si/Al ratios and concentrated synthesis mixtures favor the crystallization of FER materials. Increasing the size of the cyclic amine or decreasing the aluminum content leads to the crystallization of other phases or the creation of excessive amounts of connectivity defects. TMA cations play a decisive role in the synthesis of the FER materials, and their presence allows the use of HMI to synthesize FER. Proton MAS NMR is used to quantify the accessibility of pyridine to acid sites in these FER samples, where it is found that the FER + HMI + TMA sample contains only 27% acid sites in the 8-MR channels, whereas FER + Pyr and FER + Pyr + TMA contain 89% and 84%, respectively. The constraint index (CI) test and the carbonylation of dimethyl ether (DME) with carbon monoxide are used as probe reactions to evaluate how changes in the aluminum distribution in these FER samples affect their catalytic behavior. Results show that the use of Pyr as an SDA results in the selective population of acid sites in the 8-MR channels, whereas the use of HMI generates FER zeolites with an increased concentration of acid sites in the 10-MR channels

Influence of Preparation Conditions on the Catalytic Performance of Mo/H-ZSM-5 for Methane Dehydroaromatization

[EN] Methane, the main component of natural gas, is an interesting source of chemicals and clean liquid fuels, and a promising alternative raw material to oil. Among the possible direct routes for methane conversion, its aromatization under non-oxidative conditions has received increasing attention, despite the low conversions obtained due to thermodynamic limitations, because of its high selectivity to benzene. Mo/H-ZSM-5, the first bifunctional zeolite-catalyst proposed for this reaction, is still considered as one of the most adequate and has been widely studied. Although the mono- or bifunctional nature of the MDA mechanism is still under debate, it is generally accepted that the Mo species activate the C-H bond in methane, producing the intermediates. These will aromatize on the Bronsted acid sites of the zeolite, whose pore dimensions will provide the shape selectivity needed for converting methane into benzene. An additional role of the zeolite's Bronsted acid sites is to promote the dispersion of the Mo oxide precursor. Here, we show the influence of the different preparation steps-metal incorporation, calcination and activation of the Mo/ZSM-5- on the metal dispersion and, therefore, on the activity and selectivity of the final catalyst. Metal dispersion is enhanced when the samples are calcined under dynamic conditions (DC) and activated in N-2, and the benefits are larger when the metal has been incorporated by solid state reaction (SSR), as observed by FESEM-BSE and H-2-TPR. This leads to catalysts with higher activity, increased aromatic selectivity and improved stability towards deactivation.This work has been supported by the Spanish Government-MICINN through "Severo Ochoa" (SEV-2016-0683, MINECO) and RTI2018-101033-B-I00 (MCIU/AEI/FEDER, UE), and by Generalitat Valenciana (AICO/2019/060). The authors thank B. Esparcia for technical assistance and the electron Microscopy Service of the UPV for their help in sample characterization.Portilla, MT.; Llopis, FJ.; Moliner Marin, M.; Martínez, C. (2021). Influence of Preparation Conditions on the Catalytic Performance of Mo/H-ZSM-5 for Methane Dehydroaromatization. Applied Sciences. 11(12):1-17. https://doi.org/10.3390/app11125465S117111