Carbon nanotube toughened aluminium oxide nanocomposite

This paper describes the mechanical properties of carbon nanotube-reinforced Al₂O₃ nanocomposites fabricated by hot-pressing. The results showed that compared with monolithic Al₂O₃ the fracture toughness, hardness and flexural strength of the nanocomposites were improved by 94%, 13% and 6.4% respectively, at 4 vol.% CNT additions. For 10 vol.% CNT additions, with the exception of the fracture toughness, which was improved by 66%, a decrease in mechanical properties was observed when compared with those for monolithic Al₂O₃. The toughening mechanism is discussed, which is due to the uniform dispersion of CNTs within the matrix, adequate densification, and proper CNT/matrix interfacial connections.     

Exploiting W. Ellison model for seawater communication at gigahertz frequencies based on world ocean atlas data

Electromagnetic (EM) waves used to send signals under seawater are normally restricted to low frequencies () because of sudden exponential increases of attenuation () at higher . The mathematics of EM wave propagation in seawater demonstrate dependence on relative permeability (), relative permittivity (), conductivity (), and of transmission. Estimation of and based on the W. Ellison interpolation model was performed for averaged real‐time data of temperature () and salinity () from 1955 to 2012 for all oceans with latitude/longitude points and 101 depth points up to 5500 m. Estimation of parameters such as real and imaginary parts of , , , , loss tangent (tan ), propagation velocity (), phase constant (), and contributes to absorption loss () for seawater channels carried out by using normal distribution fit in the 3 GHz–40 GHz range. We also estimated total path loss () in seawater for given transmission power and antenna (dipole) gain. MATLAB is the simulation tool used for analysis.     

A novel method for vehicle detection in high-resolution aerial remote sensing images using YOLT approach

Multimedia Tools and Applications - Owing to the innovative challenge stood by an intergovernmental military alliance, we have proposed a model to find novel solutions in the areas of data...     

LTE efficiency when used in traffic information systems: A stable interest aware clustering

Long‐term evolution (LTE) technology is critical for the envisioned usage scenarios in the Internet of Vehicles. An important usage scenario is traffic information systems (TIS) for vehicular ad hoc networks (VANETs) that depend on LTE for the delivery of non‐safety information to vehicles. TISs are centralized data warehouses that collect and process traffic information and subsequently allow vehicles to receive such information before and during a road trip. Considering the extensive deployment of VANETs, the LTE demand for TIS is expected to increase. Therefore, we explore and quantify the inefficiency of LTE when used in TIS. By envisioning basic test case scenarios, we establish the trends of data usage while commuting and providing insights into how LTE usage in TIS may lead to the inefficient use of the available wireless spectrum during road trips. To reduce identified inefficiency in LTE usage and cluster instability due to the high speed of the vehicles, we proposed a novel stable interest‐aware clustering (SIAC) mechanism. SIAC consider VANETs mobility constraint, LTE link quality, and exploit interest of the vehicles, in cluster formation phase. Resulting in the reduction in the data demand of the vehicles and frequency of link failures among the vehicles and provides transmission path stability. SIAC performs well as compared with the existing approaches shows more cluster stability and reduces the LTE usage for driving assistance and route planning applications.     

First principle studies of structural, elastic, electronic and optical properties of Zn-chalcogenides under pressureMuhammad Bilala, M. Shafiqa, Iftikhar Ahmada, Imad Khana,*

Structural, elastic, electronic and optical properties ofzinc-chalcogenides （viz. ZnX, X = S, Se and Te） are studied in zinc-blende structure under hydrostatic pressure using the full-potential linearized augmented plane wave method. Generalized gradient approximation is used for exchange correlation potentials. Pressure-dependent lattice constants and bulk moduli are obtained using the optimization method. Young＇s modulus, Poisson＇s ratio, internal strain parameter and anisotropy are also calculated. The higher values of Young＇s modulus in comparison to the bulk modulus show that these materials are hard to break. Poisson＇s ratio is computed for the first time for these materials to the best of our knowledge and its values show higher ionic contribution in these materials. Modified Becke and Johnson （mBJ） method is used to study band gaps, density of states, dielectric function and refractive index. Electronic study shows direct band gaps convert to indirect band gaps with increasing pressure in the case of ZnS and ZnTe. We compared our results with other theoretical and experimental results. Our results are far better than other theoretical results because mBJ is the best technique to treat Ⅱ-Ⅵ semiconductors.     

Accumulation of heavy metals in edible parts of vegetables irrigated with waste water and their daily intake to adults and children,District Mardan,Pakistan

Green vegetable crops irrigated with wastewater are highly contaminated with heavy metals and are the main source of human exposure to the contaminants. In this study accumulation of eight heavy metals (Cu, Ni, Zn, Cr, Fe, Mn, Co and Pb) in green vegetables like Allium cepa, Allium sativum, Solanum lycopersicum and Solanum melongena, irrigated with wastewater in Mardan are studied using Atomic Absorption spectrophotometer. The studied metals in vegetable grown on wastewater irrigated soil were significantly higher than those of tube well water irrigated soil and WHO/FAO permissible limits (P < 0.05). The most heavily contaminated vegetable was wastewater irrigated A. cepa, where the accumulation of Mn (28.05 mg kg^?1) in the edible parts was 50-fold greater than A. cepa irrigated with tube well water irrigated soil. It may be concluded that both adults and children consuming these vegetables grown in wastewater irrigated soil ingest significant amount of these metals and thus can cause serious health problems.     

Durable and Recyclable Superhydrophobic Fabric and Mesh for Oil–Water Separation

The authors report durable and recyclable nanocomposite superhydrophobic coatings on two different substrates of fabric and mesh as prepared by titania nanoparticles and polydimethysiloxane (PDMS). The felted wool fabric and the steel mesh are initially coated with a thin layer of PDMS, which is followed by the deposition of nanocomposite coating of titania nanoparticles embedded in PDMS. The dual surface modification of two kinds of substrates generates highly hydrophobic surface character, which is retained after durability performance as measured in ultrasonication, sand, and emery paper abrasion tests. Oil–water separation experiments are performed using water mixtures with four oils, that is, n‐hexane, toluene, kerosene, and diesel to ensure the industrial applications of prepared composite materials. Moreover, nanocomposite coatings are tested for several cycles of oil–water separation in harsh conditions such as hot water, sodium chloride, and hydrochloric acid. The adopted approach improves the separation performance by inducing durability of the prepared nanocomposite coatings along with introducing recyclable character.     

Service level agreements (SLAs) parameter negotiation between heterogeneous 4G wireless network operators

We are currently witnessing a growing interest of network operators to migrate their existing 2G/3G networks to 4G technologies such as long-term evolution (LTE) to enhance the user experience and service opportunities in terms of providing multi-megabit bandwidth, more efficient use of radio networks, latency reduction, and improved mobility. Along with this, there is a strong deployment of packet data networks such as those based on IEEE 802.11 and 802.16 standards. Mobile devices are having increased capabilities to access many of these wireless networks types at the same time. Reinforcing quality of service (QoS) in 4G wireless networks will be a major challenge because of varying bit rates, channel characteristics, bandwidth allocation and global roaming support among heterogeneous wireless networks. As a mobile user moves across access networks, to the issue of mapping resource reservations between different networks to maintain QoS behavior becomes crucial. To support global roaming and interoperability across heterogeneous wireless networks, it is important for wireless network operators to negotiate service level agreement (SLA) contracts relevant to the QoS requirements. Wireless IP traffic modeling (in terms of providing assured QoS) is still immature because the majority of the existing work is merely based on the characterization of wireless IP traffic without investigating the behavior of queueing systems for such traffic. To overcome such limitations, we investigate SLA parameter negotiation among heterogeneous wireless network operators by focusing on traffic engineering and QoS together for 4G wireless networks. We present a novel mechanism that achieves service continuity through SLA parameter negotiation by using a translation matrix, which maps QoS parameters between different access networks. The SLA matrix composition is modeled analytically based on the G/M/1 queueing system. We evaluate the model using two different scheduling schemes and we derive closed form expressions for different QoS parameters for performance metrics such as packet delay and packet loss rate. We also develop a discrete event simulator and conduct a series of simulation experiments in order to understand the QoS behavior of corresponding traffic classes.