Application of NOMA for cellular-connected UAVs:opportunities and challenges

Unmanned aerial vehicles (UAVs) have gained considerable interests in numerous civil applications.To push forward its potentials,cellular-connected UAVs have be...     

The effects of short‐term and long‐term exposure to extreme cold environment on the body’s physiological responses: An experimental study

There is little epidemiological data to make reliable conclusions about the effects of exposure to cold on the body’s physiological responses. The current study aimed to address this lacuna in the available research. The study sample consisted of 50 outdoor mechanic workers as a case group and 15 staff members as a control group used in the outdoor automechanic workshops. Air environmental factors, including dry‐bulb temperature and air velocity, were measured by the portable hot wire thermo anemometer in the workstation of each subject. The body’s physiological responses were also measured during daily activities in accordance with ISO 9886. Using Semmes–Weinstein monofilament, touch sensory tests were conducted for determining hands’ sensorineural functions. The baseline measurements showed the mechanic workers had lower finger sensation levels and finger skin temperatures than the control group (p < 0.05). This may be attributed to long‐term exposure to acute cold air during cold seasons. However, after short‐term exposure to extreme cold environment, the mechanic workers showed lower losses in finger skin temperatures and finger sensation levels than the control group ( p < 0.05). The findings confirmed that prolonged localized cold exposure among mechanic workers can result in localized habituation of vasoconstrictor responses.     

Efficient radix-r adders for nanoelectronics

In this study, a new design method and efficient designs for radix-r adders are proposed for carbon nanotube field effect transistor (CNFET) FET nanotechnology. This application also investigates the capability of the nanoscale device for designing high-performance analogue circuits. The proposed designs benefit from the unique electrical properties of CNFET, such as near-ideal current voltage characteristics, very high transconductance, high-performance switches and very high-performance and high-gain binary inverters, at nanoscale. Moreover, adjustable threshold voltage and the same mobility of electrons and holes in a CNFET facilitate the design and modification procedures. The proposed design can be considered as an instance of a general adder, capable of adding radix-r digits with high precision. It is noteworthy that a very limited number of carbon nanotube diameters for designing the proposed adder are needed, which enhance the manufacturability. The proposed circuits are designed based on arithmetic relations and are also verified at 32 nm feature size using HSPICE and the Stanford standard SPICE model.     

The effect of ultrasound waves on the efficiency of membrane clarification of pomegranate juice

Pomegranate juice has a turbid appearance, which poses difficulties in its concentration process. Membrane clarification can be used to clarify pomegranate juice; however, membrane fouling reduces the permeate flux, limiting its effectiveness. Ultrasound at 30 kHz was used to reduce membrane fouling. Results were compared with the data obtained for membrane clarification without ultrasonic treatment at the same temperature. Results showed that permeate flux increased with ultrasonic treatment. Evaluation of different membrane fouling characteristics showed that the total membrane resistance fell due to the reduction in irreversible fouling and cake resistance. However, ultrasound did not affect the thick caking produced in membrane processing at low feed‐flow rates. Evaluation of the physicochemical properties of pomegranate juice showed that ultrasound can decrease antioxidant activity due to the reduction in total anthocyanin content. Also, total soluble solid content and acidity of pomegranate juice changed with ultrasonic treatment.     

A switched energy saving position controller for variable-pressure electro-hydraulic servo systems

The electro-hydraulic servo system (EHSS) demonstrates a relatively low level of efficiency compared to other available actuation methods. The objective of this paper is to increase this efficiency by introducing a variable supply pressure into the system and controlling this pressure during the task of position tracking. For this purpose, an EHSS structure with controllable supply pressure is proposed and its dynamic model is derived from the basic laws of physics. A switching control structure is then proposed to control both the supply pressure and the cylinder position at the same time, in a way that reduces the overall energy consumption of the system. The stability of the proposed switching control system is guaranteed by proof, and its performance is verified by experimental testing.     

Prediction of Methane Generation of Ozone-Treated Sludge from a Wastewater Treatment Plant

Prior to anaerobic digestion of waste activated sludge (WAS), the pre-treatment of sludge including ozonation is utilized to enhance the rate of methane generation and turn it to feasible bio-resource energy. Biochemical methanogenic potential (BMP) test is a common tool to estimate the biodegradability of raw and ozonated WAS, although, it is a time consuming test requiring expensive gas analysis. The objective of this research is to recognize key parameters essential to predict biodegradability of WAS and create a valid Artificial Neural Networks (ANN) for estimating sludge biodegradability. The results reflect that ANN is an effective estimation tool.     

A novel FPGA-programmable switch matrix interconnection element in quantum-dot cellular automata

The Quantum-dot cellular automata (QCA) is a novel nanotechnology, promising extra low-power, extremely dense and very high-speed structure for the construction of logical circuits at a nanoscale. In this paper, initially previous works on QCA-based FPGA’s routing elements are investigated, and then an efficient, symmetric and reliable QCA programmable switch matrix (PSM) interconnection element is introduced. This element has a simple structure and offers a complete routing capability. It is implemented using a bottom-up design approach that starts from a dense and high-speed 2:1 multiplexer and utilise it to build the target PSM interconnection element. In this study, simulations of the proposed circuits are carried out using QCAdesigner, a layout and simulation tool for QCA circuits. The results demonstrate high efficiency of the proposed designs in QCA-based FPGA routing.     

Ergodic Sum Rate Maximization for Underlay Spectrum Sharing with Heterogeneous Traffic

A radio resource allocation framework is proposed for underlay spectrum sharing. The ergodic capacity maximization problem in orthogonal frequency division multiple access-based network on point to multi point transmission is formulated and solved. Heterogeneous traffic is also considered in which two types of traffic is assumed: streaming traffic which has strict delay requirements, and elastic traffic with flexible delay requirements. Considering the effect of channel state information (CSI) imperfection in the evaluation of the secondary users’ expected rate, we further assume that the estimated CSI between the secondary users and secondary base station (secondary channel) is not perfect. Moreover three different cases are considered depending on the availability of the CSI between the secondary base station and the primary receivers (interference channel). Using simulations, we evaluate the impact of streaming traffic and imperfect CSI on the sum capacity of the secondary elastic users for different values of parameter systems.