Mechanical and thermal properties of polyvinylchloride/olive residue flour blends treated by gamma irradiation

In this study, gamma irradiation treatments were used to improve the compatibility between poly(vinyl chloride) (PVC) and olive residue flour (ORF). The blends were subjected to gamma irradiation at doses of 10 and 70 kGy. The mechanical, thermal, and morphological behaviors of those blends have been assessed. The irradiated blends exhibit better thermal properties, higher tensile modulus, elongation, and strength at break than those of unirradiated blends. The contact angle of water on the surface of a blend irradiated at doses of 10 and 70 kGy is smaller than that for their corresponding unirradiated blend. These treatments cause surface oxidation of PVC/ORF films, as revealed by Fourier transform infrared (FTIR) spectroscopy analysis. J. VINYL ADDIT. TECHNOL., 22:273–278, 2016. © 2014 Society of Plastics Engineers     

Usage of a speech constraint for highlighting compensatory strategies developed in production of a second language

This paper deals with the underlining and the prominent display of the compensatory strategies developed by six speakers which are from different geographic regions when they express themselves in a second language very different from their mother native language. The paradigm that had been used in this study is the elocution speed as a speaking constraint in order to investigate the effects of the flow rate on the acoustical parameters of the speech signal. The analysis is performed in both time and frequency domains. We have obtained very interesting results as we have found out that the used constraint allows a good discrimination between different speakers on the basis of their native language.     

Hydraulic permeability of structures made of geotextile sand containers: Laboratory tests and conceptual model

The permeability values were obtained for more than 15 different geotextile sand container (GSCs)-structures. The influence of the size of the sand containers (four different sizes were tested), arrangement and geometry was investigated. First results show that the size of the container represents one of the primary factors influencing the permeability but the method of placement of the GSCs also plays a significant role (different methods of placing resulted in a permeability with more than a 50% difference). The results show that the flow through the GSC-structure is solely governed by the gaps between neighbouring containers and that the flow through the sand fill in the containers can be neglected.In addition, several GSC-structures with the same geometry and the same size of containers but with different arrangements (and thus different permeabilities) were tested under wave action in the twin wave flume of LWI. The results show that the mode of placement of elements strongly affects the permeability and the stability of GSC-structures. Placement of the containers in such a way that the contact areas among containers are maximized resulted in the largest overall stability against wave action. A conceptual model for the determination of the permeability of GSC-structures is proposed.     

Design and development of a data acquisition system for photovoltaic modules characterization

Testing photovoltaic generators performance is complicated. This is due to the influence of a variety of interactive parameters related to the environment such as solar irradiation and temperature in addition to solar cell material (mono-crystalline, poly-crystalline, amorphous and thin films). This paper presents a computer-based instrumentation system for the characterization of the photovoltaic (PV) conversion. It based on a design of a data acquisition system (DAQS) allowing the acquisition and the drawing of the characterization measure of PV modules in real meteorological test conditions.     

Tunneling of Graphene Massive Dirac Fermions Through a Double Barrier

We study the tunneling of Dirac fermions in graphene through a double barrier potential. This is allowing the carriers to have an effective mass inside the barrier as generated by a lattice miss-match with the boron nitride substrate. The consequences of this gap opening on the transmission are investigated and the realization of resonant tunneling conditions is analyzed.     

TLM method for thermal investigation of IGBT modules in PWM mode

The insulated gate bipolar transistor (IGBT) is popularly used in high power, high frequency power-electronic applications such as motor control and inverters. These applications require well designed thermal management system to ensure the protection of IGBTs. Choice simulation tools for accurate prediction of device power dissipation and junction temperature become important in achieving optimised designs.In this paper, thermal analysis of a 1200 A, 3.3 kV IGBT module was investigated and analysed using the three-dimensional transmission line matrix (3D-TLM) method. The results show a three-dimensional visualisation of self-heating phenomena in the device. Since the comparison TLM results with the analytical solutions do not exist for this IGBT module, we use the MSC.NASTRAN tool to find the similar range of the temperatures. Results are compared.Typically, IGBT is used in a three-phase inverter leg where the control signals are generated via PWM scheme so, the prediction of the temperature rise is important in the pulse operation conditions for the IGBT device. A view of the dynamic thermal temperature rise is obtained with 100 W-step pulse dissipation applied at IGBT chips. The temperature rises are calculated using TLM method during the PWM load cycles. Simulations give clear indications of the importance of the spreader material and are helpful in selecting the proper one.TLM has been successful in modelling heat diffusion problems and has proven to be efficient in terms of stability and complex geometry. The three-dimensional results show that method has a considerable potential in power devices thermal analysis and design.     

The methodology of self-controlled case series studies

The self-controlled case series method is increasingly being used in pharmacoepidemiology, particularly in vaccine safety studies. This method is typically used to evaluate the association between a transient exposure and an acute event, using only cases. We present both parametric and semiparametric models using a motivating example on MMR vaccine and bleeding disorders. We briefly describe approaches for interferent events and a sequential version of the method for prospective surveillance of drug safety. The efficiency of the self-controlled case series method is compared to the that of cohort and case control studies. Some further extensions, to long or indefinite exposures and to bivariate counts, are described.     

Selective oxidation of propane over PMoV?M/α‐Al2O3 (M: Co,Fe, or Ni)

Alumina supported phosphovanodomolybdic acid and alumina supported phosphovanodomolybdic acid‐transition metal ions (M: Fe³⁺, Co²⁺, or Ni²⁺) were prepared by impregnation. The thermal decomposition, in situ at 400°C, of supported catalysts showed the formation of V₂O₅, P₂O₅, MoO₃ and MoO₃, CoMoO₄, (Mo_0.3V_0.7)₂O₅ phases, on the alumina surface, in the presence of H₄PMo₁₁VO₄₀/α‐Al₂O₃ and H₄PMo₁₁VO₄₀? Co/α‐Al₂O₃, respectively. The catalytic activity of alumina‐supported catalysts was evaluated in the reaction of propane oxidation at 380 and 400°C. The addition of transition metal increases the conversion and changes the reaction products distribution. The reaction conditions (temperature and propane/oxygen ratio) have also modified the behaviour of the studied catalysts.     

Evaluation using online support-vector-machines and fuzzy reasoning. Application to condition monitoring of speeds rolling process

A method for process condition monitoring and evaluation, which combines the online support vector machine (SVM) regression and the fuzzy sets methods, is proposed. To account for the time dependence, the proposed approach is based on moving windows in order to take into account the past and new data for the model’s adaptation. The fuzzy analysis is then applied to the generated residual data to give an evaluation of the condition monitoring. The proposed approach is applied to hot rolling for constructing a complementary condition monitoring system, which permits an online quality evaluation in the rolling process. Simulation results based on residual data show that the new approach is easily implementable.     

Chemical modification of olive pomace by various esters and silane

The olive pomace was modified chemically to improve the interface between the polymer matrix and the cellulosic fillers. The modification was done using various ester types having the same nature, however, with different chain lengths and one silane. Before the surface treatment, the olive pomace was extracted with acetone to remove contaminants on the surface, using Soxhlet apparatus. The transesterification of olive pomace with the different ester components, i.e., vinyl acetate, vinyl propanoate, and vinyl butanoate, and the condensation reaction with dichlorodimethylsilane was confirmed by Fourier transform infrared (FTIR) analysis. Moreover, the treatment of olive pomace with vinyl acetate improves the thermal stability and the sample records higher onset temperature of degradation as measured by thermogravimetric analysis (TGA). The results obtained indicated also that the reaction between the hydroxyl groups of waste flour and the acetyl, propionyl, pivalyl, and silane groups have occurred. The modified wood flours exhibited a decrease in the hydrophilicity as supported by the lower moisture content. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010