Effect of graphene oxide on the physical,mechanical and thermo-mechanical properties of neoprene and chlorosulfonated polyethylene vulcanizates

The present research work demonstrated the effect of graphene oxide (GO) on the physical, mechanical, thermo-mechanical etc., properties of neoprene (CR) and chlorosulfonated polyethylene (CSPE) vulcanizates. CR and CSPE based nanocomposites were prepared by both solution intercalation and melt intercalation methods. The changes obtained in the morphology, cure characteristics, mechanical, thermal, thermo-mechanical properties of the rubber nanocomposites have been widely investigated. X-ray diffraction analysis (XRD) and transmission electron microscopic (TEM) analysis of the samples revealed partial exfoliated structure of GO containing rubber composites. Mechanical, thermal, cure and thermo-mechanical properties of the elastomeric nanocomposites were improved compared to the neat rubbers.     

Hygrothermal deformation of orthotropic nanoplates based on the state-space concept

This paper deals with the investigation of the effect of hygrothermal conditions on the bending of nanoplates using Levy type solution model employing the state-space concept. The nanoplates are assumed to be subjected to a hygrothermal environment. The two-unknown function plate theory is used to derive the governing differential equations on the basis of Eringen's nonlocal elasticity theory. The governing equations contain the small scale effect as well as hygrothermal and mechanical effects. These equations are converted into a set of first-order linear ordinary differential equations with constant coefficients. Analytical solution of bending response for nanoplates under combinations of simply supported, clamped and free boundary conditions is obtained. Comparison of the results with those being in the open literature is made. The influences played by small scale parameter, temperature rise, the degree of moisture concentration, boundary conditions, plate aspect ratio and side-to-thickness ratio are studied.     

Co9S8–carbon composite as anode materials with improved Na-storage performance

The synthesis and electrochemical performance of a composite of Co₉S₈ nanoparticles and amorphous carbon is studied as an anode material for sodium-ion batteries. The Co₉S₈–carbon composite powder was fabricated through a one-pot spray pyrolysis process using thiourea and polyvinylpyrrolidone as sulfur and carbon sources, respectively. The Co₉S₈ nanoparticles are entirely covered by an amorphous carbon layer. The initial discharge and charge capacities of the Co₉S₈–carbon composite powder were 689 and 475 mA h g⁻¹, respectively, at a current density of 0.5 A g⁻¹. The Co₉S₈–carbon composite powders exhibited a stable cyclability with a reversible capacity of 404 mA h g⁻¹ for the 50th cycle and a superior rate capability compared with bare Co_1−xS powder. The improvement of Na-storage performance could be attributed to the small size and entanglement of the Co₉S₈ nanoparticles within the carbon matrix.     

Feasibility and effort estimation models for medium and small size information mining projects

Information mining is a sub-discipline of Information Systems which provides the non-trivial knowledge needed for making decisions inside an organization. Although such projects have different features from Software Engineering ones, they share some of their problems. Among these problems two are highlighted: unmanaged risks and inaccurate estimations of necessary resources to complete the project. In this context, this paper presents two ad-hoc models to be applied in Small and Medium-sized Enterprises: one for assessing project feasibility and the other for estimating the resources and time required to carry out the project. Both models should be applied at the beginning of the project.     

Antifungal activity mode of Aspergillus ochraceus by bacillomycin D and its inhibition of ochratoxin A (OTA) production in food samples

The inhibition effects of bacillomycin D on the growth of Aspergillus ochraceus and the production of ochratoxin A (OTA) in food samples were investigated. The mycelia growth and sporulation were completely inhibited by 30 μg/mL of bacillomycin D. Microscopic morphological changes such as the distortion of hyphae and the disruption of spores at 20 μg/mL of bacillomycin D were significantly observed. The use of bacillomycin D resulted in cell damage, nucleic acids and proteins divulge, and more production of reactive oxygen species (ROS), and all these factors actively contributed to the promotion of apoptosis of A. ochraceus. In addition, 90 μg/g of bacillomycin D completely inhibited the growth of A. ochraceus and the production of OTA in food samples. Our results suggested that bacillomycin D showed a significant antifungal activity against A. ochraceus that could be used as a potential natural antimicrobial to control food contamination and ensure food safety.     

Secondary school educators' perceptions and practices in handling cyberbullying among adolescents: A cluster analysis

School educators play an important role in cyberbullying management. Since scarce earlier research indicated low perceived competence of school educators in handling cyberbullying, more insight is needed in what determines their actions and how to improve these practices. This study assessed school educator practices, their perceptions and context factors from a behavior change theoretical framework, and investigated educator clusters related to this. An online survey was conducted among 451 secondary school educators (teachers, principals, school counselors). School educators mostly used recommended actions (i.e. conversations with pupils, enlisting professionals for support, parental involvement, providing supportive victim advice). Four educator clusters were identified: ‘referrers’ (65%), ‘disengaged’ educators (14%), ‘concerned’ educators (12%) and ‘use all means’ educators (9%). The first two clusters were less adept at handling cyberbullying and comprised mostly teachers, particularly indicating a need for training teachers. Our findings show a need for tailored educator training, e.g. by job position, gender, school size and grade. The behavior change theoretical framework can help target educators' particular needs.