Theoretical study and practical application of the capillary film solar distiller

In the south of Algeria, to supply sufficient fresh water for the population, desalination is necessary because water resources (underground and geothermal) are brackish.This paper presents the theoretical study and the results of experiments carried out with a capillary film multi-effect distiller installed in the south of Algeria (in a village near Touggourt, where the temperature of the groundwater is about 65°C at the source). The name of this device is DIFICAP ( stiller with a lm in illary motion).The aim of our study is to improve the efficiency of this distiller. The research and development of this desalination process is carried out under the following aspects: modelisation of heat and mass transfer, experimentation under direct solar radiation in South Algeria and technical development to aim to optimize the efficiency of this distiller.The theoretical and experimental results show that the efficiency of this distiller increases when the temperature of the brackish water, the intensity of the solar radiation and the number of stages increase.     

Metabolically blocked analogs of housefly sex pheromone: I. Synthesis of alternative substrates for the cuticular monooxygenases

Cuticular monooxygenases in the cuticle of the female houseflyMusca domestica oxidize (Z)-9-tricosene to m-9,10-epoxytricosane and to (Z)-9-tricosen-14-one. One possible explanation for these two products is that a single monooxygenase accepts the alkene substrate in two different orientations. Eleven analogs of (Z)-9-tricosene bearing methyl substituents, cyclopropyl groups, fluorine substituents, deuterium substituents, and additional double bonds were synthesized to probe the substrate requirements of this monooxygenase system. In addition, the 11 corresponding epoxides were prepared to aid in identification of the metabolites of each modified alkene.     

Fatigue life prediction under variable loading based on a new damage model

To examine the performance of nonlinear models proposed in the estimation of fatigue damage and fatigue life of components under random loading, a batch of specimens made of 6082 T 6 aluminium alloy has been studied and some of the results are reported in the present paper. The paper describes an algorithm and suggests a fatigue cumulative damage model, especially when random loading is considered. This paper contains the results of mono-axial random load fatigue tests with different mean and amplitude values performed on 6082 T 6 aluminium alloy specimens. Cycles were counted with rainflow algorithm and damage was cumulated with a new model proposed in this paper and with the Palmgren–Miner model. The proposed model has been formulated to take into account the damage evolution at different load levels and it allows the effect of the loading sequence to be included by means of a recurrence formula derived for multilevel loading, considering complex load sequences. It is concluded that a ‘damaged stress interaction damage rule’ proposed here allows a better fatigue damage prediction than the widely used Palmgren–Miner rule, and a formula derived in random fatigue could be used to predict the fatigue damage and fatigue lifetime very easily. The results obtained by the model are compared with the experimental results and those calculated by the most fatigue damage model used in fatigue (Miner’s model). The comparison shows that the proposed model, presents a good estimation of the experimental results. Moreover, the error is minimized in comparison to the Miner’s model.     

Stress distribution in dental implant with elastomeric stress barrier

Dental implant has been used and studied for the replacement of missing teeth for many years. It has been well known that the success of dental implant is heavily dependent on initial stability and long-term Osseointegration due to optimal stress distribution in the surrounding bones. For this reason, the search of the rational solutions to reduce these stresses has become an important issue in this field. Alternatives to reduce the forces transmitted to implants have been studied, including variations in implant positioning, implant design, prosthesis shape, occlusal requirements, prosthetic components and prosthetic materials. Thus, a new concept of adding a bio-elastomer to the prosthetic components of implant system was interposed between the abutment and the framework crown in order to damp the occlusive shocks and to attenuate the stress concentrated at the implant/bone interface. The new implant system design was assessed by the three dimensional finite element techniques using ABAQUS program to study the effect of elastomer material under an occlusal load on the induced equivalent von Mises interface stresses. These stresses were compared with those provoked by the standardized implant. The von Mises stress distribution indicated that stress was maximal around the top of the implant with varying intensities in the different loading cases. The stress was highest in the cortical bone at the neck of implant and lowest in the cancellous bone. Overall, the novel implant provoked lower interface stresses only in the cortical bone due to the stress shielding effect of the elastomeric stress barrier.     

Nanodispersions stabilized by β-cyclodextrin nanosponges: application for simultaneous enhancement of bioactivity and stability of sage essential oil

The aim of this work was to stabilize oil-in-water nanoemulsion containing sage (salvia officinalis) essential oil, for enhancing its physicochemical stability and enlarging its industrial applications. New β-cyclodextrin nanosponges were synthesized by polycondensation using naphthalene dicarboxylic acid as cross-linking agent, the latter system was characterized by FTIR spectroscopy, SEM, BET, and powder XRD. Nanoemulsions stabilized by free β-cyclodextrin or nanosponges were prepared, their physicochemical properties were determined (particles size, zeta potential, viscosity, turbidity, and essential oil content) and their stability was studied at different storage temperatures (4?°C, 20?°C, and 40?°C) during 3?months. Pharmaceutical application of prepared nanoemulsions was investigated in vitro by dissolution test study and in vivo by their antidiabetic activity evaluation in rats. Sage essential oil nanoemulsion stabilized by β-cyclodextrin-naphthalene dicarboxylic acid nanosponges presents very high stability and promising uses in pharmaceutical industry.     

Evaluating Regression Models for Temporal Prediction of Wi-Fi Device Mobility

Wireless Personal Communications - The ability to predict the arrival and residence time of mobile users at a particular place is essential for the development of a wealth of new applications and...     

Metabolically blocked analogs of housefly sex pheromone: II. Metabolism studies

Analogs of (Z)-9-tricosene (Z9–23: Hy) bearing methyl substituents, cyclopropyl groups, fluorine substituents, and additional double bonds were used to probe the substrate requirements for the monooxygenase system that converts Z9–23: Hy to the corresponding epoxide and ketone. Three of the seven analogs tested, 10-fluoro-(Z)-14-tricosene, 10,10-difluoro-(Z)-14-tricosene, and 14-methyl-(Z)-9-tricosene, were metabolized to the corresponding epoxide. Compounds with two methyl groups, a cyclopropane group, a hydroxy group, or an additional double bond at the 14 position were not epoxidized at the 9,10 position. This suggests that only minimal structural change at the 14-position of Z9–23: Hy is allowed with retention of metabolic activity. None of the analogs tested were hydroxylated at the position equivalent to the 14 position of Z9–23:Hy. Of the 13 analogs tested as inhibitors of Z9–23:Hy metabolism, the two compounds that were the most effective inhibitors in both male and female houseflies were (Z)-14-tricosen-10-one and 1-nonyl-1-[(Z)-4-tetradecen-1-yl]-cyclopropane. These data show that the poly substrate monooxy genase that metabolizes Z9–23: Hy in the housefly has very strict structural requirements for the substrate.     

Classic and local analysis of corrosion behaviour of graphite and stainless steels in polluted phosphoric acid

In phosphoric acid solution (40% H₃PO₄), the corrosion behaviour of graphite and stainless steels was studied by the use of different electrochemical methods, namely polarization curve analysis, electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). The combined effect of chemical impurities and the increase of medium temperature was studied to approach the real conditions in the process of phosphoric acid manufacturing. It was found that the current density measured by polarization curves increased with the presence of chloride and sulphate ions in the acid solution whatever the tested material. Compared to stainless steels, graphite had the best corrosion resistance in polluted phosphoric acid. However, for graphite the increase of temperature from 20 to 80 °C induced an increase of the corrosion rate and potential and a decrease of the resistance confirmed by EIS results. Subsequently, local currents were detected at the surface of the sample by using the scanning vibrating electrode technique. From the data obtained, graphite surface manifested a distinctive behaviour from that of stainless steels. A generalized corrosion was occurred on graphite whereas a localized corrosion was observed for stainless steels. These results show a clear interest of graphite as component material in some of the equipments of the phosphoric acid industry.     

Synthesis of MIL-101@g-C<Subscript>3</Subscript>N<Subscript>4</Subscript> nanocomposite for enhanced adsorption capacity towards CO<Subscript>2</Subscript>

MIL-101@g-C₃N₄ nanocomposite was prepared by solvothermal synthesis and used for CO₂ adsorption. The parent materials (MIL-101 and g-C₃N₄) and the MIL-101@g-C₃N₄ were characterized by X-ray diffraction, argon adsorption/desorption, Fourier transform infrared spectroscopy, thermal analysis (TG/DTA), transmission electronic microscopy, and Energy-dispersive X-ray spectroscopy. The results confirmed the formation of well-defined MIL-101@g-C₃N₄ with interesting surface area and pore volume. Furthermore, both MIL-101 and MIL-101@g-C₃N₄ were accomplished in carbon dioxide capture at different temperatures (280, 288, 273 and 298 K) at lower pressure. The adsorption isotherms show that the nanocomposite has a good CO₂ adsorption affinity compared to MIL-101. The best adsorption capacity is about 1.6 mmol g^?1 obtained for the nanocomposite material which is two times higher than that of MIL-101, indicating strong interactions between CO₂ and MIL-101@g-C₃N₄. This difference in efficacy is mainly due to the presence of the amine groups dispersed in the nanocomposite. Finally, we have developed a simple route for the preparation of an effective and new adsorbent for the removal of CO₂, which can be used as an excellent candidate for gas storage, catalysis, and adsorption.