Background: Deterioration of maxillofacial silicone properties due to microbial colonization is a common problem and leads to the replacement of the prosthesis. Incorporation of the antimicrobial agent into the silicone could be a solution. The purpose of this study was to evaluate the effect of silver-zinc zeolite addition on some mechanical properties of a maxillofacial silicone (VST-50). Materials and methods: Total 120 specimens were fabricated and divided into 3 groups: 40 specimens for tear strength test, 40 specimens for tensile and percentage of elongation tests and 40 specimens for Shore A hardness and surface roughness. Each group was divided into 4 subgroups according to the amount of zeolite added (0% “control”, 0.5%, 1% and
... Show MoreThe ZnTe alloy was prepared as deposited thin films on the glass substrates at a thickness of 400±20 nm using vacuum evaporation technique at pressure (1 × 10-5) mbar and room temperature. Then the thin films under vacuum (2 × 10-3 mbar) were annealing at (RT,100 and 300) °C for one hour. The structural properties were studied by using X-ray diffraction and AFM, the results show that the thin films had approached the single crystalline in the direction (111) as preferred orientation of the structure zinc-blende for cubic type, with small peaks of tellurium (Te) element for all prepared thin films. The calculated crystallite size (Cs) decreased with the increase in the anne
... Show MoreSeveral industrial wastewater streams may contain heavy metal ions, which must be effectively removal
before the discharge or reuse of treated waters could take place. In this paper, the removal of copper( II)
by foam flotation from dilute aqueous solutions was investigated at laboratory scale. The effects of
various parameters such as pH, collector and frother concentrations, initial copper concentration, air flow
rate, hole diameter of the gas distributor, and NaCl addition were tested in a bubble column of 6 cm inside
diameter and 120 cm height. Sodium dodecylsulfate (SDS) and Hexadecyl trimethyl ammonium bromide
(HTAB) were used as anionic and cationic surfactant, respectively. Ethanol was used as frothers and the
Adsorption is one of the most important technologies for the treatment of polluted water from dyes. Theaim of this study is to use a low-cost adsorbent for this purpose. A novel and economical adsorbent was used to remove methyl violet dye (MV) from aqueous solutions. This adsorbent was prepared from bean peel, which is an agricultural waste. Batch adsorption experiments were conducted to study the ability of the bean peel adsorbent (BPA) to remove the methyl violet (MV) dye. The effects of different variables, such as weight of the adsorbent, pH of the MV solution, initial concentration of MV, contact time and temperature, on the adsorption behaviour were studied. It was found experimentally that the time required to achieve equilibrium
... Show MoreResumen
Este trabajo de investigación ofrece uno de los temas relevantes en la lengua, el cual es estudiar las dimensiones sintácticas, semánticas y pragmáticas de las preposiciones, en general, y de las dos preposiciones "Para" y "Por" en concreto, en una unidad linguística más amplia que la llamada "Oración". En la parte referida al estudio de las dos preposiciones mencionadas, estudiamos sus distntos usos funcionales, usos que se acercan, unas veces, entre sí y se alejan en otras.
Abstract
... Show MoreRESUMEN:
Pretendemos hacer con este trabajo un breve recorrido sobre lo que han dicho algunos gramáticos de las construcciones condicionales, a la par señalaremos los criterios que los mismos establecen y siguen para diferenciar entre distintos tipos de estructuras condicionales o entre las construcciones que ellos entienden o consideran como tales y las que no, atendiendo fundamentalmente a dos criterios; formal y semántico-pragmático. El presente trabajo tiene como objetivo la clasificación y la descripción de las construcciones condicionales, demostrando que no todas las condicionales son hipotéticas ni todas las hipotéticas son condicionales.
Abstract
We intend to make this work
... Show MoreThe ascorbic acid content of juices of some fruits and pharmaceutical tablets of Vitamin C was determined by a homemade apparatus of DIE technique using a thermocouple as heat sensor. The method is simple, speed, low cost and the different types of turbid, colored samples can be analyzed without any problem. The results were of a valuable accuracy and precision, and the recovery of results was with acceptable values
In this paper Alx Ga1-x As:H films have been prepared by using new deposition method based on combination of flash- thermal evaporation technique. The thickness of our samples was about 300nm. The Al concentration was altered within the 0 x 40.
The results of X- ray diffraction analysis (XRD) confirmed the amorphous structure of all AlXGa1-x As:H films with x 40 and annealing temperature (Ta)<200°C. the temperature dependence of the DC conductivity GDC with various Al content has been measured for AlXGa1-x As:H films.
We have found that the thermal activation energy Ea depends of Al content and Ta, thus the value of Ea were approximately equal to half the value of optical gap.