Journal of Civil and Environmental Engineering

The creep behaviors and microstructures of Al-0.7Fe and Al-0.7Fe-0.2Sc alloy are investigated through creep tests, optical microscope, electron probe micro-analyze and transmission electron microscope observations. It is found that the steady state creep rates of Al-0.7Fe-0.2Sc are smaller than that of Al-0.7Fe under different temperatures at 70 Mpa. An overview of microstructure is given, the interactions between intermetallic phases and dislocations are investigated, with an emphasis on the Al3Sc precipitates. The mechanism controlling creep-resistance is explained by Orowan strengthening mechanism. The magnitude of Δσ Or can afford dislocations to bypass Al3Sc precipitates in Al-0.7Fe-0.2Sc alloy. The counter flow of the vacancies and solute atoms are induced to expound the dislocation motion mechanism.

Traditional dispersion models; such as the travel time distribution based normal distribution model and geometric distribution model; are dedicated to traffic situations with conventional traffic signs and signals; which may not be able to depict the platoon dispersion phenomenon under a connected vehicle system with in-vehicle advisory messages. This research re-examines the traditional dispersion models with suitable adjustment considering impacts of in-vehicle messages. A correction factor was employed to update the travel time distribution model; while travel time distributions of leading vehicles with and without the in-vehicle messages were simulated in a driving simulator with forty-five subjects tested. Parameter calibrations for travel time dispersion of traffic flow in work zone and intersections with sun glares were conducted to illustrate the entire modeling and calibration procedure. With more practical simulations and field tests; the flow dispersion models can be further calibrated for more applications in traffic flow simulation and optimizations.

Sweet basil’s raw material grown in the experimental modules of the newest water-stream hydroponics (cylindrical, gully, continuous) and in classical hydroponics exceeds soil culture with dry weight 2.3-4.8 times. The more intensive synthesis of essential oil is observed during the first cut (July) in cylindrical and classical hydroponics and partially in continuous hydroponics and during the second cut (August) in conditions of gully hydroponics and soil culture. Simultaneously during vegetation the maximal output of essential oil (1.3-6.4 times) was provided in cylindrical hydroponics system. High content of the essential oil’s most important ingredient methyl chavicol (43%) is observed in cylindrical hydroponics system during July and August cut.

Wood ash is generated as residual/waste from combustion done in boilers at pulp and paper mills, steam power plants, and other thermal power generating facilities. Since wood is a renewable resource for energy and an environmentally friendly material, there is an increased requirement of using waste wood for the purpose of energy production thus leading to formation of more wood ash waste. The study focuses on incorporation of wood ash in combination with ordinary Portland cement while using it for various structural works. A critical review study in sieve analysis, consistency, and water absorption, setting time and slump tests of wood ash added to OPC will produce significant results to emphasize the detailed study process. Uncontrolled burning of saw dust to form wood ash is used as a partial replacement of cement, thereby changing its physical and chemical properties. These properties are found somewhat similar to fly ash. The concrete mixes are replaced with the amorphous wood ash as an admixture of cement having grain size less than 75 microns in proportions of 5%, 10%, 15%, 20%, 25% and 30% by weight of cement. In this Study, a research work is conducted for determining the change in workability or consistency of concrete mix, compressive strength, split tensile strength, flexural strength, etc., along with review of some durability properties. Foundry Sand is used as fine aggregate to obtain efficient results.

One of the goals of local transportation agencies is to improve the quality of life for citizens and visitors by ensuring the efficient and safe movement of people and goods through the roadway system. Maintenance and rehabilitation of pavements are necessary to ensure that roadway networks continue to perform at their optimum. Currently, maintenance and rehabilitation of roadway networks depend on several factors including pavement condition indices, funding availability, among others. Previous studies have established relationships between crash frequency and pavement condition indices. However, the combined influence of speed, volume, and crash frequency on pavement indices, and thereby pavement management efforts has not been thoroughly examined. In this paper, a multinomial logistic regression was employed for 193 arterial segments to establish a new categorical variable: Composite Safety Index (CSI). The CSI values or ratings were based on pavement indices, crash frequency, traffic volumes and vehicular speeds to help categorize pavement sections for either maintenance or rehabilitation. The results indicated that the selected independent variables were statistically reliable in ranking pavement sections for rehabilitation or maintenance based on their CSI values.

In the present paper, the coupled behavior of structural systems obtained by connecting a moment resisting frame structure with a vertical elastic truss, known in the literature as strong-back, which acts as a mast by imposing to the structure a given lateral deformed shape, is investigated. The rigid behavior of the strong-back, which is designed in order to remain in the elastic field under strong seismic ground motion, imposes a uniform inter storey drift along the frame height, thus avoiding undesired effects such as soft storey and weak storey mechanisms. Consequently, the whole structural system may be, at first approximation, modelled as an equivalent Single Degree of Freedom system thus allowing for an analytical description of its response. In particular, in the work the attention is paid to the mutual actions exchanged by the strong-back and the frame by solving the static equilibrium equations, assuming a shear type behavior for the frame. Finally, some numerical simulations of frame systems with strong-back systems as subjected to earthquake ground motions are developed, encompassing both shear type frames and frames with flexible beams.

Abu Dhabi Police (ADP) is as a major client in the United Arab Emirates (UAE). ADP undertakes several capital projects every year; and uses two project managers (PMs) i.e., distributed leadership on their construction schemes. These dual PMs are chosen during the design stages of upcoming project schemes. A research did investigate the efficacy of this approach where 145 potential respondents were asked to complete a questionnaire survey and 90 (62%) responded. The data collected were analysed by descriptive and inferential statistics to reveal that more of the PMs perceived themselves to have more leadership than management characteristics. They also supported the use of distributed leadership which informed the development of a new practical framework for its implementation. This framework was validated with 10 top managers of ADP who supported its recommendation for adoption.