Temperature and density determination for heat flux in the area of the shaft-bushing contact

The problem of temperature and density determination for heat fluxes in the friction area for the shaft-bushing conjugation is solved as an ill-defined nonstationary problem by measuring the temperature within the bushing. The bushing (coal-plastic) temperature within the friction area and the absolute values of the temperature gradient are demonstrated to stabilize within five minute of testing independently of the load regime. Under an increase in contact pressure, the absolute values of the temperature gradient grow with increase in the test duration.     

Concrete dielectric properties investigation using microwave nondestructive techniques

The paper deals with dielectric properties of concrete and the effect of frequency, curing time and water to cement (w/c) ratio, concrete compression strength, steel fibre concrete and moisture content on the dielectric properties. The concrete dielectric properties such as transmission coefficients, reflection coefficients, dielectric constants and loss factors; were investigated using microwave nondestructive testing (MNDT) technique. The MNDT system consists of transmit and receive horn lens antennas, a vector network analyzer, mode transitions, and a printer. The horn lens antennas are used for minimizing diffraction effects due to the edges of the sample. Electromagnetic waves at microwave frequency range 7.0–13.0 GHz using free-space microwave method was used for measuring dielectric properties of concrete. Concrete specimens were prepared using different w/c ratios and different compressive strengths. Concrete dielectric properties were measured and correlated with compressive strength and w/c ratio of concrete, curing time. The experimental results indicate that microwave non-destructive technique has correlated well with to determine the compressive strength and w/c ratios of concrete. The results also show the potential to be used to determine the percentage of fiber. This technique is easy to adapt for in situ measurements.     

CRUST: Implementation of clustering and routing functions for mobile ad hoc networks using reactive tuple-spaces

This work builds on the LIME (Linda in mobile environment) tuple space framework to implement a system that offers clustering and routing capabilities for mobile ad hoc network (MANET) environments, and provide an agent-like architecture for running distributed and collaborative applications on mobile devices. This paper describes the components that were added to the LIME system, which were necessary to implement engagement and disengagement of hosts into and out of spaces, and illustrates the developed engagement mechanism and routing protocol with the aid of example scenarios. The paper then discusses the system performance obtained from implementing its functions using the ns-2 network simulation software. The obtained results indicate that the system works reasonably well under different conditions (host transmission range, host mobility, and density of hosts in the network). For instance, the time for a host to join a space is well under one second in sparse spaces and goes up to only two seconds in moderately dense spaces). Moreover, the system offers routing performance that is moderately better than that of ZRP, both in terms of route discovery delay and generated traffic.     

The thermal and economic characteristics of solar air collectors with different delta turbulators arrangement

The benefits of using a solar air collector with different array delta turbulators absorber plate are experimentally investigated to assess this type of collector under western and middle of Iraq climate conditions. The solar collector was investigated with four different absorber plate in which flat plate, in‐line delta turbulators, staggered delta turbulators and inclined staggered delta turbulators with different mass airflow rate. The economic characteristics and overall thermal performance of the collector are compared with other heating systems. The major findings show that the delta turbulators enhance the economic characteristics and the overall thermal performance of collectors due to vortex generation and damping the development of the thermal boundary layer in the direction of airflow. A substantial enhancement is observed in lowering both life‐cycle cost and increasing energy saving with delta turbulators. This study will likewise provide a new direction to the work trend in western and middle of Iraq climate conditions during winter days.     

Triple-helix directed cleavage of double-stranded DNA by benzoquinoquinoxaline-1,10-phenanthroline conjugates

Oligonucleotide-directed triple-helix formation provides a rational means to interfere with genomic DNA targets and to direct modifications at specific sites. We have developed a new class of compounds that, at low concentrations, efficiently targets and damages double-stranded DNA specifically at the site where a triple-helical structure is formed. In these new compounds, a triple-helix-specific intercalator-benzoquinoquinoxaline (BQQ)-was coupled to one of two isomeric 1,10-phenanthrolinecarboxaldehyde derivatives. 1,10-Phenanthroline derivatives are known to cleave DNA in the presence of copper ions. The obtained BQQ-1,10-phenanthroline (BQQ-OP) conjugates were compared with regard to their ability to cleave triple-helix DNA. Both conjugates displayed a sequence preference inside the triple-helical site, as judged from the more pronounced cleavage obtained at stretches of TAxT base triplets.     

Proliferating cell nuclear antigen (PCNA) expression in oral squamous cell carcinoma - an aid to conventional histological grading?

Decreased oxygen delivery and cellular hypoxia are major factors in the pathophysiology of shock. We studied the effects of 100% O2 at 0.1 and 0.3 MPa (1 and 3 atm abs) in severe hemorrhagic shock in awake, unrestrained rats. Shock was induced by withdrawing 50% of the total blood volume within 120 min. Blood pressure, heart rate, and the electroencephalogram (EEG) were recorded during the first 6 h of the protocol. The animals were observed for 7 days. The shock protocol resulted in 60 and 90% mortality after 1 day and at the end of 7 days, respectively. A single 90-min exposure to O2 at 0.1 and 0.3 MPa, which was started 30 min after bleeding, maintained mean arterial blood pressure at significantly higher values compared to untreated controls throughout the exposure period (P < 0.05). Oxygen therapy at both doses also improved the long-term survival rate and survival time significantly (P < 0.01). No clinical or EEG sign of CNS O2 toxicity was detected in O2-treated animals. Our results indicate that O2 given alone after severe bleeding exerts a beneficial effect on the long-term outcome of hemorrhagic shock in awake, unrestrained rats.     

Cloud point extraction of 2,4−dichlorophenol from aqueous samples employing β−cyclodextrin

In this study, β?cyclodextrin (β?CD) was used to enhance the extraction of 2,4?dichlorophenol (2,4?DCP) from the aqueous sample in cloud point extraction (CPE) using spectrophotometric method. Several parameters have been investigated with and without the presence of β?CD modifier, such as pH, equilibration temperature, analyte concentration, and water content in the CPE and CPE?βCD systems, respectively. Equilibrium data are described by the Langmuir isotherm in both CPE systems with and without β?CD modifier. The thermodynamic parameters (positive values of ΔH° and ΔS°, negative values of ΔG°) indicate that the solubilization of 2,4?DCP in a polyethylene glycol silicone surfactant (DC193C) is endothermic, entropy gained, and spontaneous in both systems. In the CPE?βCD system, the results show that the β?CD modifier is capable of enhancing the extraction of 2,4?DCP pollutant from aqueous samples.