Structure and Transport Properties of Polymer Grafted Nanoparticles

We perform molecular dynamics simulations on a bead-spring model of pure polymer grafted nanoparticles (PGNs) and of a blend of PGNs with a polymer melt to investigate the correlation between PGN design parameters (such as particle core concentration, polymer grafting density, and polymer length) and properties, such as microstructure, particle mobility, and viscous response. Constant strain-rate simulations were carried out to calculate viscosities and a constant-stress ensemble was used to calculate yield stresses. The PGN systems are found to have less structural order, lower viscosity, and faster diffusivity with increasing length of the grafted chains for a given core concentration or grafting density. Decreasing grafting density causes depletion effects associated with the chains leading to close contacts between some particle cores. All systems were found to shear thin, with the pure PGN systems shear thinning more than the blend; also, the pure systems exhibited a clear yielding behavior that was absent in the blend. Regarding the mechanism of shear thinning at the high shear rates examined, it was found that the shear-induced decrease of Brownian stresses and increase in chain alignment, both correlate with the reduction of viscosity in the system with the latter being more dominant. A coupling between Brownian stresses and chain alignment was also observed wherein the non-equilibrium particle distribution itself promotes chain alignment in the direction of shear.This paper is based on work supported in part by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST). It was also supported by Award No. CBET-1033349 from National Science Foundation (NSF). The authors are grateful to Professor D. L. Koch, Professor L. A. Archer, Professor I. Cohen, Professor A. Z. Panagiotopoulos, Dr. Xiang Chen, U. Agarwal, S. Srivastava, and P. Agarwal for useful discussions and suggestions

QUALITY OF SERVICE OF SMALL HARDWARE COMPANIES IN A NORTHERN PERUVIAN PROVINCE

Currently, the quality of service provided by companies plays a fundamental role as a strategy to meet customer expectations and achieve customer satisfaction. The objective of the study was to identify the customers' perception of the quality of service provided by companies in the hardware sector in the province of Tumbes. In the methodology, the approach was quantitative, descriptive level and non-experimental design. The sample consisted of 487 clients of 10 companies that sell construction products. A questionnaire was adapted as a data collection instrument to evaluate the quality of service in a service company. The results showed that high levels of service quality prevailed with 72.48%, followed by medium with 25.87% and low with 1.64%. High levels of service quality were also found according to the sociodemographic variables sex, age and marital status. It is concluded that the majority of the clients considered the quality of service of the small hardware companies to be high, while only a small percentage considered the quality of service to be low

THE PRINCIPLE OF INTEGRITY AND THE FRAGMENTATION OF PUBLIC PROCUREMENT

Objective: Through this work, a study on the integrity of the human being and the fractionation of public procurement has been carried out.Methods: As part of the study, the authors reviewed scientific works on the subject.Results: After analyzing the contracting law 30225, its regulations and other aspects that are part of the contractual procedure, certain factors have been determined that intervene in the actions of the agents in charge of public contracting, such as: i) normative disparity; ii) incapacity of those in charge of the selection processes; and iii) acts of corruption, which put at risk the denaturalization of the norms, generating the splitting of a contract.Conclusions: The splitting of a contracting procedure corresponds more to a subjective decision where the official or servant in charge of the contracting process has the power to discern the good from the bad. The bad decision that entails an illicit conduct will generate liability

Synthesis and Assembly of Nonspherical Hollow Silica Colloids Under Confinement

Hard peanut-shaped colloids were synthesized and organized into a degenerate crystal (DC), a phase previously observed only in simulations. In this structure, particle lobes tile a triangular lattice while their orientations uniformly populate the three underlying crystalline directions

Emotional Intelligence in Times of Covid-19: a Comparative Study in Peruvian Universities

Objective:The aim of the study was to compare emotional intelligence in Peruvian university students from public and private universities.Theoretical framework: In higher education, emotionally intelligent students have the ability to interact appropriately with others, achieve good academic results, and reach personal and professional goals.Method: The methodology was descriptive-comparative, the sample consisted of 838 university students of both sexes from public (471) and private (364) universities belonging to the coast, highlands and jungle regions of Peru. A sociodemographic form created for the study and the emotional intelligence scale (TMMS-24) were used as measurement instruments.Results and conclusion:The results showed that university students over 30 years of age, women, those from the highlands and those who worked had high levels of emotional intelligence.Implications of the research:It is necessary for university institutions to reorganize their academic conditions and provide the necessary inputs to apply socioemotional strategies to students. Researchers linked to the lines of research on emotional intelligence should develop predictive studies to know which factors may be predicting adequate or inadequate emotional intelligence in university students.Originality:This study demonstrates that it is essential to attend to and provide emotional intelligence tools to those students whodo not have the necessary resources to face different situations in the face of the COVID-19 pandemic and contributes to the training of educators, especially environmental educators in crisis contexts