The importance of specifying proper aggregate grading for achieving satisfactory performance in pavement applications has long been recognized. To improve the specifications for superior performance, there is a need to understand how differences in aggregate gradations within the acceptable limits may affect unbound aggregate base behavior. The effects of gradation on strength, modulus, and deformation characteristics of high-quality crushed rock base materials are described here. Two crushed rock types commonly used in constructing heavy-duty granular base layers in the State of Victoria, Australia, with three different gradations each were used in this study. The gradations used represent the lower, medium, and upper gradation limits for heavy-duty base materials specified by the State of Victoria’s road agency (VicRoads). Modified compaction tests were conducted first to determine the moisture-density relationship of all mixes. Further, California bearing ratio (CBR), unconfined compressive strength (UCS), and repeated load triaxial (RLT) tests were then performed to study the effects of different gradations on strength, resilient modulus (MR), and deformation resistance. Further, permanent deformation and MR results were modeled using two popular models for each to explain the effect of gradation on the mixtures’ characteristics. The results indicate that the gradation that provides the best characteristics varies depending on the type of material used. For the materials tested here, coarse and medium gradations provide the best mixture characteristics in relation to CBR, MR, and permanent deformation. Fine gradation mixtures of these materials have lower values of these measures but are still considered acceptable considering relevant specification for the intended application.
The optimum process conditions of the electrochemical deposition of carbon nanotubes (CNT) have been established by using developed, cheap and simple system. It has been found that temperature affects on the rate, purity and the yield of CNT obtained in this process. The electrochemical behavior of CNT deposition, kinetic and thermodynamic parameters were also discussed.
This work is concerned with the study of the effect of cement types, particularly OPC and SRPC, which are the main cement types manufactured in Iraq. In addition, study the effect of mineral admixtures, which are HRM and SF on the resistance of high performance concrete (HPC) to internal sulphate attack. The HRM is used at (10%) and SF is used at (8 and 10)% as a partial replacement by weight of cement for both types. The percentages of sulphate investigated are (1,2 and 3)% by adding natural gypsum as a partial replacement by weight of fine aggregate. The tests carried out in this work are: compressive strength, flexural strength, ultrasonic pulse velocity, and density at the age of 7, 28, 90 and 120 days.
The r
... Show MoreThe research tagged (Perceived Organizational Support in High Performance) deals with identifying the extent of the impact of perceived organizational support as an explanatory variable on high performance as a response variable for the purpose of reaching appropriate mechanisms that enable colleges of the University of Baghdad to exploit the perceived organizational support in achieving the required high performance and pursuit of its goals. The researcher relied on the descriptive and analytical approach in carrying out the research. An intentional sample was selected and reached (70) persons from the higher leadership of the colleges represented by (deans, assistants deans, heads of departments) that r
... Show MoreThis study was conducted in a laboratory experiment at the University of Baghdad, College of Science, computing Department, 5 km from the center of Baghdad city, in 2021 to evaluate the sorting method for the tomato crop. The experiments were conducted in a factorial experiment under a complete randomized design with three replications and using SAS analysis, artificial neural network, image processing, the study of external characteristics, and physical features; fruit surface area and fruit circumference were 1334.46 cm2,57.53 cm2 and free diseases. The error value was less than zero, while training with outputs recorded the highest value and which was 5. The neural network's performance between the input and the mean square of th
... Show MoreIn order to evaluate the effect of seed size, plant growth regulators and some chemical materials on seed vigour and seedling growth of rice (Oryza sativa L.) an experiment was conducted in 2015 at Laboratories of Agriculture and Marshes College, University of Thi-Qar. Factorial experiment in CRD was used with four replications in two factors. The first factor included three seed sizes (4.6-5.1, 5.2-5.7 and 5.8-6.3 mm). The second factor was seeds soaking treatments (KNO3 6 gl-1, CaCl2 20 gl-1, salicylic acid 20 mg l-1, cytokinin 40 mg l-1, gibberllic acid 400 mg l-1, ascorbic acid 40 mg l-1 and seeds soaked in distilled water). The results showed that the largest seed size influenced significantly and gave the higher averages of germinatio
... Show MoreAbstract: Background: Tribuls terrestris increases levels of various hormones in steroid family including testosterone, DEHA, and estrogen and for this reason improves sport performance, fertility in men and women, sexual function in men and women. There is, at present, lack of scientific confirmation of these supposed benefits. Therefore, this study aims to investigate the possible effect(s) of Tribuls terrestris on the mouse ovarian morphology and function, alone and in combination with other ovulation modulator agent (clomiphene citrate). Materials & Methods: A total of 49 sexually mature healthy Norway albino female mice were used in this study; 25 for pilot study and 24 for the experimental study. Experimental animals were divided
... Show MoreQuercetin, one of the flavonoids family member, can be found in many vegetables, fruits, and beverages with a noticeable nutritional pharmacological properties. This study was aimed to evaluate the ability of quercetin to inhibit lipopolysaccharide (LPS) that induced lethal toxicity in vivo, and to elucidate the importance of the quercetin as an antitumor agent in breast cancer cell line MCF-7.In vivo experiments included the effect of hesperidin and LPS on the liver and spleen of male mice. In the liver, the antioxidant activity was measured by estimating the concentration of glutathione (GSH), and catalase (CAT), while in the spleen, the concentration of cytokines was measured including IL-33 and TNF-α. In vitro experiments included MTT
... Show MoreBackground: This in vitro study was carried out to evaluate the effect of various endodontic irrigants (sodium hypochlorite, ethylene diaminetetracetic acid and normal saline) on sealing ability of (Biodentine, mineral trioxide aggregate, and amalgam) used to repair furcal perforations. Material and methods: One hundred and twenty extracted human molars with divergent roots were used in this study. A standard root canal access cavity was prepared in each tooth and furcal perforation was made and was standardized by using k file size 100 instrument to get a perforation of (1.32mm) in diameter .The teeth were randomly divided in to three groups of 40 teeth according to the type of material used to repair the perforations (Group A: The furcal
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