Dopant Segregation and Heat Treatment Effects on the Electrical Properties of Polycrystalline Silicon thin Films

This paper reports the effect of heat treatment on the electronic activity of grain boundaries of polycrystalline silicon. The results obtained show that for the same concentration of doping, the arsenic doped films are more resistive and have less free carriers than boron doped films. The arsenic atoms have a greater tendency to segregate at the grain boundaries than boron atoms. We also noticed that the heat treatment before implantation reduces the number of trap carriers and the quantity of doping atoms at the grain boundaries. For low doping, the concentration of the free charge carriers improves after the heat treatment by 100 % and 23 % for arsenic and boron doping respectively.     

Experimental evaluation of quinolinium and isoquinolinium derivatives as corrosion inhibitors of mild steel in 0.5 M H<Subscript>2</Subscript>SO<Subscript>4</Subscript> solution

The 1-methylquinolinium iodide (I) Qui⁺, I^– and 2-methylisoquinolinium iodide isoQui⁺, I^– were investigated as a corrosion inhibitors for mild steel in sulfuric acid using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The results indicated that the corrosion inhibition efficiency and extent of surface coverage were increased with increase in inhibitors concentrations. Polarization curves revealed that both inhibitors acted as a mixed-type inhibitor. The thermodynamic parameters were evaluated for corrosion inhibition process. The adsorption of both inhibitors on mild steel surface obeyed Langmuir adsorption isotherm.     

Partial replacement of carbon black with graphene in natural rubber/butadiene rubber based tire compound: Investigation of critical properties

Journal of Polymer Research - In this study, we prepared graphene oxide-based styrene/acrylic elastomeric disks (GSAE) from sugarcane bagasse/ferrocene (GO) and styrene/acrylic emulsion (SAE) to...     

Design of New Cardanol Derivative: Synthesis and Application as Potential Biobased Plasticizer for Poly(lactide)

A novel biobased plasticizer made of cardanol is designed for poly(lactide) (PLA). This cardanol‐derived plasticizer, i.e., methoxylated hydroxyethyl cardanol (MeCard), is synthesized through methoxylation of the double bonds on the side chain of cardanol, and characterized by ¹H NMR and mass spectrometry. The plasticization effect of MeCard on the molecular structure, morphology, thermal and mechanical properties of PLA is evaluated and compared to that of a commercial cardanol, i.e., hydroxyethyl cardanol (pCard). The plasticization efficiency of MeCard is demonstrated by a substantial decrease of the glass transition temperature and storage modulus together with a significant increase of the elongation at break as compared to neat PLA. Moreover, MeCard exhibits higher plasticization performance than pCard toward PLA. Such behavior is related to a higher miscibility and compatibility between PLA and MeCard thanks to the methoxylation of the double bonds on the side chain of cardanol as shown by SEM micrographs.

     

Study of effect of old corrugated cardboard in properties of polypropylene composites: Study of mechanical properties,thermal behavior,and morphological properties

The investigation of the economical use of lignocellulose waste, which is one of the environmental problems facing nations, is ongoing. In this study, waste cardboard paper fiber reinforcing polypropylene (PP) composites was developed. In order to modify the PP matrix maleated PP (MA‐g‐PP) a 5 wt% and a grafting rate of 1 and 2 wt% was used as a compatibilizer. The effects of fiber and compatibilizer content as well as graft content are evaluated by mechanical, thermal property measurements, and scanning electron microscopy (SEM). The compatibilizer improved all mechanical properties significantly. Thus, the tensile strength of MA‐g‐PP‐containing composites increases compared to PP/cardboard composites paper content increases. However, the tensile modulus of a PP‐based composite increases with an increase in paper fiber with the compatibilizer having little effect. SEM revealed that the addition of MA‐g‐PP generates strong interactions between a PP matrix and paper fibers. However, the addition of the MA‐g‐PP compatibilizing agent gives a significant improvement on the crystallization of the composites, whereas the compatibilized PP/old corrugated cardboard (OCC) composites have higher crystallinity (Xc) than uncompatibilized PP/OCC composites. The MA‐g‐PP also diminished the water absorption in the composites. J. VINYL ADDIT. TECHNOL., 22:231–238, 2016. © 2014 Society of Plastics Engineers     

Biomarkers of meat tenderness: Present knowledge and perspectives in regards to our current understanding of the mechanisms involved

Biomarkers of the meat quality are of prime importance for meat industry, which has to satisfy consumers' expectations and, for them, meat tenderness is and will remain the primary and most important quality attribute. The tenderization of meat starts immediately after animal death with the onset of apoptosis followed by a cooperative action of endogenous proteolytic systems. Before consideration of the biomarkers identified so far, we present here some new features on the apoptotic process. Among them, the most important is the recent discovery of a complex family of serpins capable to inhibit, in a pseudo-irreversible manner, caspases, the major enzymes responsible of cell dismantling during apoptosis. The biomarkers so far identified have been then sorted and grouped according to their common biological functions. All of them refer to a series of biological pathways including glycolytic and oxidative energy production, cell detoxification, protease inhibition and production of Heat Shock Proteins. Some unusual biomarkers are also presented: annexins, galectins and peroxiredoxins. On this basis, a detailed analysis of these metabolic pathways allowed us to identify some domains of interest for future investigations. It was thus emphasized that mitochondria, an important organelle in the production of energy from carbohydrates, lipids and proteins are a central element in the initiation and development of apoptosis. It was therefore stressed forward that, in fact, very little is known about the postmortem fate of these organelles and their multiple associated activities. Other topics discussed here would provide avenues for the future in the context of identifying reliable predictors of the ultimate meat tenderness.     

Communication capabilities of product networks

Instead of providing separate solutions for each individual network, a unified theory is desirable to cover the study of a class of networks. Cartesian product graphs provide a common framework to investigate the performance of several individual networks. This paper addresses communication capabilities of product networks. Communication cost is generally characterized by the diameter, the average distance, the total number of paths, the traffic intensity, the saturation level, the queue length in each node, the communication delay and the network throughput. The diameter and average distance of product networks have been studied. However, no work has addressed the remaining measures for product networks. This paper presents a unified theory to evaluate the traffic intensity and the saturation level of product networks. We have theoretically computed the traffic intensity and the saturation level. Intensive simulations have been conducted to validate the analytical results and to compute the other measures for different workloads, different networks, and different network sizes. Examples of product networks that have been investigated are multidimensional meshes, multidimensional toruses, and r‐ary n‐cube networks. We have also shown that the structure (geometry) of a network is a primary factor for network high performance. For meshes and toruses, square networks present an optimal structure. While in case of an r‐ary n‐cubes, networks with higher radix outperform those with smaller radix. In particular, cross‐cubes (4‐ary n‐cube) are shown to perform better than binary cubes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Ubiquitous robotics: Recent challenges and future trends

Ambient intelligence, ubiquitous and networked robots, and cloud robotics are new research hot topics that have started to gain popularity among the robotics community. They enable robots to acquire richer functionalities and open the way for the composition of a variety of robotic services with three functions: semantic perception, reasoning and actuation. Ubiquitous robots (ubirobots) overcome the limitations of stand-alone robots by integrating them with web services and ambient intelligence technologies. The overlap that exists now between ubirobots and ambient intelligence makes their integration worthwhile. It targets to create a hybrid physical–digital space rich with a myriad of proactive intelligent services that enhance the quality and the way of our living and working. Furthermore, the emergence of cloud computing initiates the massive use of a new generation of ubirobots that enrich their cognitive capabilities and share their knowledge by connecting themselves to cloud infrastructures. The future of ubirobots will certainly be open to an unlimited space of applications such as physical and virtual companions assisting people in their daily living, ubirobots that are able to co-work alongside people and cooperate with them in the same environment, and physical and virtual autonomic guards that are able to protect people, monitor their security and safety, and rescue them in indoor and outdoor spaces. This paper introduces the recent challenges and future trends on these topics.     

Natural brine solar pond: an experimental study

The South East of Tunisia is a sunny region. This area contains many mineral reserves of natural brine, which currently are not well exploited. These reserves are estimated to several millions of cubic metres. The abundance of solar energy and salt has led us to test the collection and storage of solar energy by a salt gradient solar pond. A small laboratory solar pond of dimensions 2 m×2 m×1 m, excavated from the ground, has been constructed at ENIT (National School of Engineers of Tunis). The salt utilised in the pond is a natural brine which comes from south of Tunisia. Temperature and solar radiation measurements have been carried out over 8 weeks to evaluate the efficiency of this pond.     

Enhancement of the Passive Direct Methanol Fuel Cells Performance by Modification of the Cathode Microporous Layer Using Carbon Nanofibers

Mass transfer is a key parameter affecting the performance of the passive direct methanol fuel cells (DMFCs), which work under natural convection. In this study, effect of carbon nanofibers (CNFs) addition to the cathode microporous layer (MPL) on the performance of the passive DMFCs was investigated. The results indicated that CNFs content has a significant influence on both of the mass transport and the electrochemical surface area (ECSA). Interestingly, addition of the CNFs (20 wt.%) leads to increase the power density of the passive DMFC to 160% compared to pristine carbon black MPL. At low current density, the CNFs content has no influence on the performance, while at high current density the maximum performance can be obtained at 20 wt.% CNFs then the performance decreases with further increase in the CNFs content. Although the highest catalyst utilization is observed at 40 wt.% CNFs, a maximum power density of 36 mW cm^–2 can be obtained at 20 wt.% CNFs and this is related to the significant effect of the mass transfer resistance under the passive operation conditions. Overall, addition of CNFs to the MPL can be considered an effective strategy to modify the passive DMFCs performance.