Effects of Ultrasound Amplitude on the Physicochemical Properties of Some Edible Oils

This research reports on the studied effect of the intensity of ultrasound (24 kHz) on the quality characteristics of olive oil, sesame oil, sunflower seed oil, and tallow olein. These characteristics (free acidity, peroxide value, conjugated dienes concentration, viscosity, iodine value, turbidity, color values, and melting behavior) were determined in oil samples before and after ultrasonic treatment. Changes in the oxidation parameters showed that the high‐intensity ultrasound treatment accelerated the deterioration of oils. In most cases, extra‐virgin sesame oil was most resistant to deterioration from sonicating treatments. The decreases in β‐carotene content and Hunter values revealed that ultrasound might have good potential for bleaching oils at an appropriate intensity and frequency. The differential scanning calorimeter thermograms, viscosity, and turbidity results indicated that ultrasound probably accelerates the polymerization of the oils. The present study has confirmed that some changes in the physicochemical parameters or structures of oil components had occurred. These changes depended on the sources and initial conditions of the oils as well as the intensity of the applied ultrasound.     

The effects of graphene oxide on the properties and drug delivery of konjac glucomannan hydrogel

Konjac glucomannan (KGM) hydrogel has good potential application in food and medical science, although to achieve this, the physical and mechanical properties need further improvement. In this study, graphene oxide (GO) was used to improve the functionality of KGM hydrogel. KGM/GO hydrogels were prepared by freezing the alkaline KGM/GO sols. Rotational rheometer was used to study the rheological properties of different alkaline KGM/GO sols. Fourier transform infrared, Raman, differential scanning calorimetry, thermogravimetric analyses, and scanning electron microscopy were used to evaluate the structure and properties of the hydrogels. In addition, different pH solutions and an in vitro assay were used to study the swelling property and the release behavior of KGM/GO hydrogels, respectively. The result revealed strong hydrogen‐bond interaction between KGM and GO. The incorporation of GO highly improved the gel properties of KGM/GO sol, higher thermal stability, and more compact structure of KGM/GO hydrogels. KGM/GO hydrogels showed better swelling properties in deionized‐distilled water and pH 7.2 PBS. The release of 5‐aminosalicylic acid (5‐ASA) from KGM/GO (KG4) hydrogel was different in various pH media, but the initial burst release effect was very severe. Therefore, incorporation of GO have a good potential in enhancing the properties of KGM hydrogel, but KGM/GO hydrogel is not an ideal carrier for 5‐ASA release. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45327.     

Surfactant‐modified feldspar: Isotherm,kinetic, and thermodynamic of binary system dye removal

In this article, surface modification of feldspar using hexadecyltrimethyl ammonium bromide (HDTMA) and its dye removal ability in single and binary systems was studied. Acid Black 1 (AB1) and Acid Red 14 (AR14) were used as model dyes. The monocomponent Langmuir isotherm model was applied to experimental data and the isotherm constants were calculated for both dyes. The monolayer coverage capacities of surfactant‐modified feldspar (HDTMA‐feldspar) for AB1 and AR14 dyes in single solution system were found as 6.369 mg/g and 3.984 mg/g, respectively. It was observed that the equilibrium uptake amounts of AB1 and AR14 dye in binary mixture onto sorbent decreased with increasing concentrations of the other dye resulting in their antagonistic effect. Equilibrium adsorption for binary systems was analyzed by using the Extended Langmuir and Jain and Snoeyink Modified Extended Langmuir models. The rate of kinetic processes of single and binary dye systems onto adsorbent was described by using two kinetics adsorption models. The pseudo‐second‐order model was the best choice among the kinetic models to describe the adsorption behavior of single and binary dyes onto HDTMA‐feldspar. Thermodynamic parameters showed that dye adsorption on HDTMA‐feldspar were exothermic and unspontaneous in nature. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Study of Structural,Electrical and Optical Properties of (200)-Oriented CdTe Thin Films Depending on the Post-deposition Low Temperature

Cadmium telluride nanoparticles (CdTe NPs) have been synthesized by a sonochemical technique, deposited on glass and quartz glass at 100°C and 2.7?×?10^?6 kPa and then studied by analyzing the x-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–Vis), current–voltage test (I–V) and scanning electron microscopy (SEM). The XRD results indicated the formation of a strong preferential (200) orientation of CdTe with a cubic zinc-blende structure on both substrates. In order to show the effect of heating on the structure and optical properties of the prepared thin films, they were annealed at temperatures of 50°C, 70°C and 100°C for 1 h. It was found that the grain size in this orientation increases with the increase of the temperature. In addition, the obtained optical band gap energies by UV–Vis measurements were in the range of 1.46–1.53 eV. The electrical properties of the prepared films were observed to increase with annealing using I–V measurements. The thin films were also found to be uniform with a small particle size, as revealed by SEM.

     

Game-theory-based lifetime maximization of multi-channel cooperative spectrum sensing in wireless sensor networks

Wireless Networks - Accurate and efficient detection of the radio-frequency spectrum is a challenging issue in wireless sensor networks (WSNs), which are used for multi-channel cooperative spectrum...     

A Graphene Oxide and Copper‐Centered Metal Organic Framework Composite as a Tri‐Functional Catalyst for HER,OER, and ORR

A composite made from the assembly of graphene oxide (GO) and copper‐centered metal organic framework (MOF) shows good performance as a tri‐functional catalyst in three important electrocatalysis reactions, namely: the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). One of the challenges in the area of electrocatalysis is to find an effective catalyst that will reduce, as well as generate, oxygen at moderate temperatures. The enhanced electrocatalytic properties and stability in acid of the GO‐MOF composite is due to the unqiue porous scaffold structure, improved charge transport and synergistic interactions between the GO and MOF. In polymer electrolyte membrane fuel cell testing, the GO‐incorporated Cu‐MOF composite delivers a power density that is 76% that of the commercial Pt catalyst.     

Simultaneous spectrum sensing,data transmission and Energy harvesting in multi‐channel cognitive sensor Networks with imperfect signal cancellation

In multichannel cognitive sensor networks, the sensor users which have limited energy budgets sense the spectrum to determine the activity of the primary user. If the spectrum is idle, the sensor user can access the licensed spectrum. However, during the spectrum sensing, no data transmits. For improving the network throughput and saving more energy consumption, we propose the simultaneous spectrum sensing and data transmission scheme where the sensor receiver decodes the received signal, and from the remaining signal, the status of the channel (idle/busy) is determined. We also consider that the sensor users are powered by a radio‐frequency (RF) energy harvester. In this case, energy harvesting, data transmission, and spectrum sensing are done simultaneously. On the other hand, we select the proper sensor users for spectrum sensing and energy harvesting. We also allocate the best channels for data transmission simultaneously so that the network throughput maximizes and the constraints on the energy consumption and the detection performance are satisfied for each band. We formulate the problem and model it as a coalition game in which sensors act as game players and decide to make coalitions. Each coalition selects one of the channels to sense and transmit data, while the necessary detection probability and false alarm probability and also the energy consumption constraints are satisfied. The utility function of a coalition is proposed based on the energy consumption, false alarm probability, detection probability, and the network throughput. This paper proposes an efficient algorithm to reach a Nash‐stable coalition structure. It is demonstrated that the proposed method maximizes the network throughput and reduces the energy consumption while it provides sufficient detection quality, in comparison to other existent methods.     

Synthesis,characterization and optical band gap of La2CuO4 nanoparticles

Pure La₂CuO₄ nanoparticles were synthesized via sol–gel process using stearic acid as complexing reagent. This method consists of the formation of an organic precursor, with metallic cations homogeneously distributed throughout the matrix. The gel was calcined at 700 °C, 800 °C and 900 °C for 4 h. The as-prepared La₂CuO₄ nanoparticles were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy and diffuse reflectance spectroscopy. Results show that the purity of La₂CuO₄ crystallites increases with the increase of heat treatment temperature from 700 °C to 900 °C. Optical properties show that La₂CuO₄ crystallites have broad absorption in the UV–vis region and the corresponding band gap is 1.24 eV.     

A lightweight anonymous two‐factor authentication protocol for wireless sensor networks in Internet of Vehicles

Internet of Vehicles (IoV), as the next generation of transportation systems, tries to make highway and public transportation more secure than used to be. In this system, users use public channels for their communication so they can be the victims of passive or active attacks. Therefore, a secure authentication protocol is essential for IoV; consequently, many protocols are presented to provide secure authentication for IoV. In 2018, Yu et al proposed a secure authentication protocol for WSNs in vehicular communications and claimed that their protocol could satisfy all crucial security features of a secure authentication protocol. Unfortunately, we found that their protocol is susceptible to sensor capture attack, user traceability attack, user impersonation attack, and offline sink node's secret key guessing attack. In this paper, we propose a new authentication protocol for IoV which can solve the weaknesses of Yu et al's protocol. Our protocol not only provides anonymous user registration phase and revocation smart card phase but also uses the biometric template in place of the password. We use both Burrow‐Abadi‐Needham (BAN) logic and real‐or‐random (ROR) model to present the formal analysis of our protocol. Finally, we compare our protocol with other existing related protocols in terms of security features and computation overhead. The results prove that our protocol can provide more security features and it is usable for IoV system.