This paper aims to investigate the flexural behavior of reinforced concrete beams considering fire resistance by adding Lightweight Expanded Clay Aggregates (LECA) to the concrete mix as partial coarse aggregate replacement. LECA is a type of porous clay with a uniform pore structure with fine, closed cells and hard, tightly sintered skin. The experimental work comprised four reinforced self-compacted concrete beams. All the specimens were identical in their geometrical layout of 1600×240×200 mm, reinforcement details, and support condition (simply supported). For all the beams, the main reinforcement was provided by two bars, each having a diameter of 12 mm, while a bar of 6 mm diameter was employed for the top and shear reinforcement. Each beam had a different replacement ratio of LECA for coarse aggregates (0, 10, 20, and 30%). All the specimens were tested under static two concentrated loads after being exposed to the fire of steady-state temperature (500 oC), 1 hr duration, and sudden cooling process. The results showed that adding LECA reduced the number and width of the generated cracks due to fire and reduced the deterioration of the ultimate load capacity and beam rigidity (stiffness).
In this work, the effect of laser energy on the properties of a calcium plasma generated by a Q-switched Nd: YAG laser at the fundamental wavelength was studied using spectroscopy. The Boltzmann plot and Stark broadening method were used to measure the main plasma parameters (electron temperature and electron density). The electron temperature ranged ( 0.169 -0.172 ) eV, the electron density ranged ( 2.10 – 2.63 ) for laser energy range of ( 400 – 700) mJ. Other basic plasma properties were also measured, including the Debye length, the number of particles in the Debye sphere, and the plasma frequency. Laser energy affects all plasma parameters, according to our results.
By extracting crystal violate dye (CV) from its aqueous solution, the photocatalytic decolorization performance of ZnO/MWCNT nanocomposite was evaluated. The nanocomposite was prepared by precipitation of ZnO and incorporates on the surface of Multi-Walled Carbon Nanotubes (MWCNT). ZnO nanoparticles were synthesized using the sol gel process with MWCNT acting as a template. They were then analyzed by XRD, SEM, and TEM, which revealed how the shape of the spherical nano ZnO interacts with the point of zero charge (pzc), which allows us to see the physical attributes. In the dipping photoreactor, which included a slurry of dye solution and ZnO/MWCNT nanocomposite, the effectiveness of decolorization was assessed. The photodecolori
... Show MoreThere are still areas around the world suffer from severe shortage of freshwater supplies. Desalination technologies are not widely used due to their high energy usage, cost, and environmental damaging effects. In this study, a mathematical model of single-bed adsorption desalination system using silica gel-water as working pair is developed and validated via earlier experiments. A very good match between the model predictions and the experimental results is recorded. The objective is to reveal the factors affecting the productivity of fresh water and cooling effect in the solar adsorption system. The proposed model is setup for solving within the commercially-available software (Engineering Equation Solver). It is implemented to so
... Show MoreWe studied at the morphology, structural setup, and optical characteristics of thin cadmium (CdSe) films a thickness of 250 nm that were created by thermal evaporation over glass, The films exhibited a hexagonal shape were crystalline, and tended to form grains in the (111) crystallographic direction, according to the X-ray diffraction examinations. These characteristics were established using the investigation's findings. Through the use of thin films of CdSe doped with Ag at a concentration of 1.5%, the crystal structure orientations for pure CdSe (25.32, 41.84) and CdSe:Ag (25.39, 41.01) that were both pure as well as those that were doped with silver were both determined. The band gap of the optical spectrum decreased by 1.93–
... Show MoreThe current study aims to produce cellulase enzyme from Streptomyces spp. isolates and study the effect of some cultural conditions on cellulase production; biofuel production from cellulotic waste through enzymatic and acids hydrolysis. Out of 74 isolates of Streptomyces sp. were screened for cellulse production in solid and liquid media. Results showed higher capability of isolate Streptomyces sp. B 167 for cellulase production and bioconversion of cellulose, therefore selected for further studies. The results of optimization revealed that the cellulase enzyme productivity by the selected isolate reached 2.1 and 2.28 U/ml after 48 h of incubation time and pH 7 respectively. Cellulase productions in tested isolate improved (2.57 U/ml) b
... Show MoreSam Shepard is considered as one of the modern American playwrights who combined the individual and the social in his plays to draw an image of a postmodern American society, and American family in particular by focusing on uniquely American aspects of culture. He is concerned with the individual in America rather than the institution. Shepard investigates, in almost all of his plays, the functions and dysfunctions of his characters, as well as the connections of individuals within the context of the family system and other social structures. The majority of his plays center on the struggle and conflict that occurs between father and son, husband and wife, and brother and brother as they strive for supremacy or for survival in a fra
... Show MoreA new Spectrophotometric method, is for individual and simultaneous determination of Ciprofloxacin hydrochloride(CIP) and Mebeverin hydrochloride(MEB) by the first and second derivative mode techniques. The first and second derivative spectra of these compounds permitted individual and simultaneous determination of CIP and MEB in concentration range of (4-28µg/mL) by measuring the amplitude of peak- to- base line and the area under peak at selected spectrum intervals. The methods showed a reasonable precision and accuracy and have been applied to determine CIP and MEB in four different pharmaceutical preparations.
The thermal degradation of cable ties of polyamide (PA6,6) neat and UV stabilized was investigated by thermogravimetry (TG) and its derivative (DTG) at several heating rates between 5 and 80 oC min-1 in helium atmosphere. High heating rates signal novel peaks in the DTG curves that indicate melting temperature of PA6,6. The kinetic parameters calculated via isoconversion and nonisothermal data using the Flynn-Wall-Ozawa, Kissinger and CoatsRedfern methods showed comparable activation energy values. Exposure of the ties to outdoor environment causes pre-mature stress cracking and brittle failure due to prevalence of crosslinking reaction occurring in the polymer chains
The current study aims to produce cellulase enzyme from Streptomyces spp. isolates and study the effect of some cultural conditions on cellulase production; biofuel production from cellulotic waste through enzymatic and acids hydrolysis. Out of 74 isolates of Streptomyces sp. were screened for cellulse production in solid and liquid media. Results showed higher capability of isolate Streptomyces sp. B 167 for cellulase production and bioconversion of cellulose, therefore selected for further studies. The results of optimization revealed that the cellulase enzyme productivity by the selected isolate reached 2.1 and 2.28 U/ml after 48 h of incubation time and pH 7 respectively. Cellulase productions in tested isolate improved (2.57 U/ml) b
... Show More