Defect and Diffusion Forum Vols. 334-335

Abstract: A shape memory alloy with a nominal composition of 84.68 wt.% Cu-11.25 wt.%Al-4.07 wt.%Ni, has been studied. Polycrystalline specimens have been quenched into water at room temperature, after heat treatment of 15 minutes at a high temperature of 1123 K. Two successive cycles from room temperature to 923 K and inversely have been performed on the non equilibrium samples. The microstructural study presented in this work has been performed using TEM (Transmission Electron Microscopy) analysis, STEM (Scanning Transmission Electron Microscopy) analysis, X-ray diffraction analysis at a variable temperature. Nanometric phase precipitation of AlNi type was observed to appear in this alloy.

Abstract: Present paper, introducing a new method of mechanical preparation of specific surfaces in a liquid medium by using unguided tools. All the presented work is originally approach based on the search of mechanics contact behaviour laws in a liquid medium. It promotes the operations of deburring and polishing, whilst causing a hardening, by varying the experimental conditions (material type, treatment time, presence or absence of chemical additions). This method was used for large dimensions pieces in order to treat the inner and outer surfaces.

Abstract: The pyrolysis of biomass is a thermal process that converts, at high yield, solid biomass into a liquid product known as bio-oil. One alternative for the production of a bio-oil of better quality and with lower oxygen content is the use of catalysts in the pyrolysis reactor, rather than an inert, a process called catalytic pyrolysis. The objective of this study was to investigate the effects on product yields and the qualities of products of two different catalysts, one acidic, a commercial fluid catalytic cracking (FCC) catalyst, and a basic one containing hydrotalcite. Inert material, a type of silica, was used as reference. The tests were conducted in a pilot plant with a circulating fluidized bed reactor, specially adapted to perform the catalytic pyrolysis tests, at temperatures of 450°C and 550°C. The results showed that the increase in the residence time of the pyrolysis vapors had a significant impact on products yields, when compared with the profile found in the literature for fast pyrolysis. The FCC catalyst presented higher deoxygenation rates by dehydration, while the hydrotalcite showed greater capacity for decarboxylation. Thus, the use of either the FCC catalyst or hydrotalcite are not suitable for intermediate pyrolysis reactors, generating a product with high water content and low content of organic compounds in bio-oil and produce more coke. None of the materials tested produced bio-oils with considerable hydrocarbons yields and presented high amounts of phenolic compounds. In general, silica had the best results in terms of yield and quality of bio-oil.

Abstract: Magnetic oxide nanoparticles with proper surface coatings are increasingly being evaluated for clinical applications such as hyperthermia, drug delivery, magnetic resonance imaging, transfection and cell/protein separations. In this work, we investigated synthesis, magnetic properties of silica coated metal ferrite, (CoFe₂O₄)/SiO₂ and manganese doped cobalt ferrite nanoparticles (Mn_x-Co_1-xFe₂O₄ with x = 0.02, 0.04 and 0.06)/SiO₂ for possible biomedical application. All the ferrites nanoparticles were prepared by co-precipitation method using FeCl₃.6H₂O, CoCl₂.6H₂O and MnCl₂.2H₂O as precursors, and were silica coated by the Stober process in directly ethanol. The composition, phase structure and morphology of the prepared core/shell cobalt ferrites nanostructures were characterized by powder X-ray diffraction (XRD), Fourier Transform infra-red spectra (FTIR), Field Emission Scanning Electron Microscopy and energy dispersive X-ray analysis (FESEM-EDAX). The results revealed that all the samples maintain the ferrite spinel structure. While, the cell parameters decrease monotonically by increase of Mn content indicating that the Mn ions are substituted into the lattice of CoFe₂O₄. The magnetic properties of the prepared samples were investigated at room temperature using Vibrating Sample Magnetometer (VSM). The results revealed a strong dependence of room temperature magnetic properties on (1) doping content, x; (2) particle size and ion distributions.

Abstract: In the emphasis on knowledge as a key competitive factor in the global economy, corporations may be overlooking a major element customer knowledge. Customer knowledge management (CKM) creates new knowledge sharing platforms and processes between companies and their customers. Customer education is one of the best ways of Customer knowledge management. Despite companies growing interest for customer education and the recent awareness in marketing literature of this concept, research on customer education remains relatively scarce. In this research a model which details the relationships between customer education and customer satisfaction was proposed and validated for nanofood product. The existence of two mediating variables was unveiled: product usage and product-usage related knowledge and skills. The experimental fieldwork was conducted in partnership with nanofood companies and their customers. In this research, clear evidence has been provided that customer education positively impacts on customer satisfaction and that specific mechanisms explain such effects.

Abstract: Degradation in walls of Historical Building with rising damp is a complex problem to solve, due to the thickness and heterogeneity of those walls. The traditionally treatment techniques used (such as watertight barriers, injection of hydrofuge products, etc.) show, sometimes, to be ineffective or too expensive, justifying the need to find a new approach. Experimental studies validate the effectiveness of a new treatment technique applied to the walls of old buildings wall base ventilation system. Building Physics Laboratory (LFC) is developing a model of this technique. The sizing of the treatment system is based on knowledge of the characteristics of the wall, of the geometry of the ventilation system and of the building being dealt with. In this work it is described the moisture transfer process between the moving air flux, inside the system, and the wall. Experimental results were used to validate the mathematical solution and the values obtained are very similar.

Abstract: Humidity, particularly rising damp, is one of the main causes of degradation of historical constructions. This type of humidity manifestation appears when the constituent materials of the walls exhibit high capillarity and these walls are in contact with water or wet soil. The treatment of rising damp in historical buildings walls is very complex. Moisture transfer in walls of old buildings, which are in direct contact with the ground, leads to a migration of soluble salts responsible for many building pathologies. In this work a sensibility study was done, using an automatic calculation program, WUFI 2D v.3.3, with the main goal to determinate the influence of some variables in the capillarity rise of different monolithic walls, namely the importance of material properties (as porosity), exterior climate and wall thickness.

Abstract: The chemical kinetics dissolution of rock salts from Sakon Nakhon Basin is characterized by drill cores and compared to geochemical compositions of natural brines obtained within the study areas in Udon Thani and Sakon Nakhon Province, Thailand. A criterion for rock salt core analysis depends upon the maximum amount of halite, based on X-ray diffractometry. Mass balance relation between brines and rock salt dissolution is conducted by the difference of initial and final weights of the core sample in each experimental batch. To monitor salinity related to its dissolution, the concentrations of total dissolved solids (TDS) are determined for each time period. The dissolution rate of rock salts can be evaluated from chemical compositions of the reactants; sodium-chloride (Na-Cl, halite) and calcium-sulphate (Ca-SO₄, anhydrite), corresponding to the TDS content, against the experimental variables of time and temperature. The most important aspect of brine and rock salt interfaces concerns the chemical kinetics developed for the rate of reaction (R) and rate constant (k) as R = k [NaC^0.7[CaSO₄]^0.8. The overall order of the reaction is experimentally 1.5 with respect to concentration of sodium chloride and calcium sulphate. Phase transitions based on the behavior of the thermodynamic free energy as a function of thermodynamic variables are accompanied by the release of heat. The activation energy needs for the dissolution reaction of rock salt is-18.08 kJ/mol. The experimental result indicates the exothermic reaction, similar to the calculation by theoretical thermodynamics. Saturation indexes of brines as a function of anhydrite reveal the supersaturating condition while rock salt dissolution reaches the equilibrium condition.

Abstract: Biopolymers of hard, brittle and low flexible polyhydroxyalkanoates (PHAs) and a soft and high elastic natural-latex rubber are blended at room temperature by using a combination technique. Concentrations of the PHAs solution are constituted at 1%, 2% and 3% w/v and mingled with fresh natural latex in different ratios (PHAs : Latex Rubber = 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1 and 10:0). After vigorous blending, forming polymeric sheets leave a dried-film pattern. Only the best 3 different ratios (4:6, 5:5 and 6:4) are selected by evaluating morphological-based information. These lead to actually define and characterize for their morphological and mechanical properties. The morphological attributes are exemplified by polarized optical microscopy and X-ray diffractometry (XRD) while the thermal characterization is determined by differential scanning calorimetry (DSC). Morphological analysis for the criterion of blending achievement indicated that there is a significant relationship among porosity, texture and shrinkage. The porosity shows obviously low to high for gradually increasing PHAs and decreasing the latex. Thus, dense texture and shrinkage relate to blending compositions between PHAs and latex. The XRD and DSC reveal certain aspects of decreasing crystallinity arising from enhancing of the latex content. A high degree of crystallinity and melting temperature relates to greater PHAs ratio. The mechanical investigations have revealed complex localization patterns of tensile strength and elastic modulus. The more PHAs concentration at 2% w/v indicates the greater elastic modulus than 3% and 1% w/v. Significant differences are found on polymeric composites of mechanical analyses between PHAs and natural latex. The constituted superiority in the ratio of 5:5 significantly differs in extension to break. Additionally, both tensile strength and elastic modulus of 2% w/v PHAs present the maximum value among them.