Two of the main advantages of segmental construction are economics, as well as the rapid construction technique. One of the forms of segmental construction, for structural elements, is the segmental beams that built-in short sections, which referred to segments. This research aims to exhibit a new technique for the fabrication of short-span segmental beams from wedge-shaped concrete segments and carbon fiber reinforced polymers (CFRP) in laminate form. The experimental campaign included eight short-span segmental beams. In this study, two selected parameters were considered. These parameters are; the number of layers of CFRP laminates and the adhesive material that used to bond segments to each other, forming short-span segmental beams. The test results showed that for segmental beams reinforced by 2-layer of CFRP laminates, undergoes less deflection and sustained considerable ultimate loading value of 38.4%–104% than beams reinforced by 1-layer. Moreover, the test of segmental beams fabricated by adhering to the concrete segments with epoxy resin exhibited an increase in ultimate loading by 16%–65% than beams constructed using cementitious adhesive for bonding the wedge-shaped segments. Theoretically, segmental beams were analyzed by the American Concrete Institute (ACI) 440.2R-17 procedure with slight modifications. The analysis gave an overestimation of flexural strength for segmental beams when compared with experimental outcomes.
The general assumption of linear variation of earth pressures with depth on retaining structures is still controversial; investigations are yet required to determine those distributions of the passive earth pressure (PEP) accurately and deduce the corresponding centroid location. In particular, for rigid retaining walls, the calculation of PEP is strongly dependent on the type of wall movement. This paper presents a numerical analysis for studying the influence of wall movement on the PEP distribution on a rigid retaining wall and the passive earth thrust location. The numerical predictions are remarkably similar to existing experimental works as recorded on scaled test models and ful
This study aims to formulate azithromycin oleogel to locally treat skin infections such as acne vulgaris and skin wound infection. Providing a form of azithromycin that can be administered topically is highly desired to prevent unwanted systemic complications including diarrhea, nausea, and abdominal pain. Additionally, it will avoid first pass metabolism, improves patient acceptance, provides an alternative in nauseated patients, decreases the dose by direct contact with the pathological site, and provides a noninvasive and convenient mode of administration. Furthermore, for treating wound infections, the gel will act as a scaffold biomaterial for wound closure besides its antibacterial effect. Herein, we propose the use of grapeseed oil-b
... Show MoreOrthodontic tooth movement is characterized by tissue reactions, which consist of an inflammatory response in periodontal ligament and followed by bone remodeling in the periodontium depending on the forces applied. These processes trigger the secretion of various proteins and enzymes into the saliva. The purpose of this study was to evaluate the activity of the lactate dehydrogenase (LDH) in saliva during orthodontic tooth movement using different magnitude of continuous orthodontic forces. Thirty orthodontic patients (12 males and 18 females) with ages 17-23 years with class II division I malocclusion all requiring bilateral maxillary first premolar extractions. Those patients were randomly divided into 3 groups according to the magnitude
... Show Morepriorities of materials research due to their promising properties, especially in the field of thermoelectricity. The efficiency or performance of thermoelectric devices is expressed in terms of the thermoelectric figure-of-merit (ZT) – a standard indicator of a material’s thermoelectric properties for use in cooling systems. The evaluation of ZT is principally determined by the thermoelectric characteristics of the nanomaterials. In this paper, a set of investigative computations was performed to study the thermoelectric properties of monolayer TMDCs according to the semiclassical treatment of the Boltzmann transport equation. It was confirmed that the thermoelectric properties of 2D materials can be greatly improved compared with thei
... Show MoreBlends of Polymethyl methacrylate (PMMA)/polyvinyl alcohol (PVA) doped with 2% weight percentage of Sn were prepared with different blend ratios using casting technique. The measurements of A.C conductivity σa.c within the frequency range (25kHz – 5MHz) of undoped and Sn doped PMMA/PVA blends obeyed the relationship σ= Aws were the value of s within the range 0 > s > 1. The results showed that σa.c increases with the increase of frequency. The exponent s showed preceding increase with the increase of PVA content for PMMA/PVA blends doped with Sn. The dielectric constant, dielectric loss, A.C electrical conductivity are varied with the concentration of PVA in the blend and frequency of applied electrical field.
Kinetic and mechanism studies of the oxidation of oxalic acid by Cerium sulphate have been carried out in acid medium sulphuric acid. The uv- vis. Spectrophotometric technique was used to follow up the reaction and the selected wavelength to be followed was 320 nm. The kinetic study showed that the order of reaction is first order in Ce(IV) and fractional in oxalic acid. The effect of using different concentration of sulphuric acid on the rate of the reaction has been studied a and it was found that the rate decreased with increasing the acid concentration. Classical organic tests was used to identify the product of the oxidation reaction, the product was just bubbles of CO2.
This research includes a study of dezincification by corrosion from brass alloys in three types of media, which are acidic solution, basic and slat solution in different percentages. The study show the higher dezincification occurs in basic solution which decrease the fatigue properties where the fatigue properties are inversely proportional with dezincification.
This study was conducted from February 2010 to December 2010. Water Samples were collected every two months in three stations in Baghdad city. The study involved the assessment of concentrations of some heavy metals such as: Chromium, Cadmium, Copper, Iron, Lead, Manganese, Nickel and Zinc. the values of chromium were undetected for the entire of the study, while the rest of the heavy metal were ranged between 0.001 -0.438 mg / l, ND -0.077 mg / L, ND -0.778 mg / l, 0.36 - 0.011 mg / l, 0.011-0 .08mg/ l, ND - 0.1985 mg / l, ND -0.0416 mg / l, respectively. The results showed that the concentrations of heavy metals were fluctuated during the study period, except Lead which have high concentrations and exceeded the permit limits in all statio
... Show MoreThe Disi water samples were collected from different Disi aquifer wells in Jordan using a clean polyethylene container of 10-liter size. A hyper-pure germanium (HPGe) detector with high- resolution gamma-ray spectroscopy and a low background counting system was used for the identification of unknown gamma-rays emitting from radionuclides in the environmental samples. The ranges of specific activity concentrations of 226Ra and 228Ra in the Disi aquifer water were found to be from 0.302 ± 0.085 to 0.723 ± 0.207 and from 0.047 ± 0.010 to 0.525 ± 0.138 Bq L−1, with average values of 0.516 ± 0.090 and 0.287 ± 0.091 Bq L−1, respectively. The average combined radium (226Ra + 228Ra) activity and radium activity ratio (228Ra/226Ra) in Disi
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