Experimental study of thermal performance improvement of a solar air flat plate collector through the use of obstacles: application for the drying of ‘yellow onion’

In the solar air flat plate collector, the insufficiency of the thermal exchange between the fluid and the absorber obliges the user to enhance their optimization. This low thermal exchange does not allow these systems to obtain their best performance or the best thermal efficiency. In our experimental study, which consists of a solar energy simulation, we have sought to improve the efficiency–temperature rise couple of the flat plate solar collector by considering several types of obstacles disposed in rows in the dynamic air vein of the collector. Thus, we have proceeded to the application of the best two systems (WDL1 and TL) for drying an agricultural product (Yellow Onion). By comparing with the collector without obstacles (WO), the thermal transfers and, consequently, the output temperature (T_OC) and the collector efficiency (η) are clearly improved. The drying times obtained with the proposed systems are very interesting. The heat quantities obtained in the case of WDL1 are very important compared with the collector WO. However, the entry to the drying cupboard of this high temperature (T_OC) in the vicinity of the solar midday must be limited to the maximal value demanded by the considered product. Copyright © 1999 John Wiley & Sons, Ltd.     

A Hybrid Modular Context-aware Services Adaptation for a Smart Living Room

Smart spaces have attracted considerable amount of interest over the past few years. The introduction of sensor networks, powerful electronics and communication infrastructures have helped a lot in the realization of smart homes. The main objective of smart homes is the automation of tasks that might be complex or tedious for inhabitants by distracting them from concentrating on setting and configuring home appliances. Such automation could improve comfort, energy savings, security, and tremendous benefits for elderly persons living alone or persons with disabilities. Context awareness is a key enabling feature for development of smart homes. It allows the automation task to be done proactively according to the inhabitant’s current context and in an unobtrusive and seamlessly manner. Although there are several works conducted for the development of smart homes with various technologies, in most cases, robust. However, the context-awareness aspect of services adaptation was not based on clear steps for context elements extraction (resp. clear definition of context). In this paper, we use the divide and conquer approach to master the complexity of automation task by proposing a hybrid modular system for context-aware services adaptation in a smart living room. We propose to use for the context-aware adaptation three techniques of machine learning, namely Naïve Bayes, fuzzy logic and case-based reasoning techniques according to their convenience.     

Distribution of natural and anthropogenic radionuclides in heavy rainfall areas in Jordan

Soil is the main reservoir of both natural and artificial radionuclides, which are transported to the human body through the food chain. Thus, assessment of the level of radioactivity in soil is of crucial importance. Artificial radionuclide concentrations in soil depend heavily on rainfall and weather conditions. In this study, the soil of the Ras Muneef area, which has the highest rainfall in Jordan, was investigated for its natural and anthropogenic radioactive content. The area was divided into four sectors and in each sector three locations were investigated depending on the land use: undisturbed, cultivated or residential. The depth profile of (137)Cs was investigated and found to depend on the land use. In the undisturbed soils, two types of depth profiles were identified: Gaussian and exponentially decreasing. The annual effective dose was found to range from 19.4 to 72.6 μSv, which falls within the worldwide ranges.     

Interference coordination for LTE-Advanced and FM broadcasting interoperability

The surest way to guarantee that multiple wireless systems can concurrently exist harmlessly, when operating in the same or adjacent channel, is by analyzing spectrum overlapping. This paper proposes a more accurate model to evaluate the interference power from co-channel and adjacent channel of orthogonal frequency division multiplexing-based long term evolution-advanced (LTE-Advanced) towards broadcasting frequency modulation systems at 800?MHz. Power spectral density overlapping factor is employed, and closed form of the interference power loss is derived. Numerical results demonstrate that the proposed method evaluates more exact interference power than the advanced minimum coupling loss (A-MCL) method, where the co-channel and adjacent channel interference powers are reduced by 1.3 and 3?dB, correspondingly, compared to that obtained using the A-MCL method. This decreases the minimum separation distance between the two systems, which can eventually lead to efficient radio spectrum resources utilization.     

Use of a Reflectance Spectroscopy Accessory for Optical Characterization of ZnO-Bi(2)O(3)-TiO(2) Ceramics

The optical band-gap energy (E(g)) is an important feature of semiconductors which determines their applications in optoelectronics. Therefore, it is necessary to investigate the electronic states of ceramic ZnO and the effect of doped impurities under different processing conditions. E(g) of the ceramic ZnO + xBi(2)O(3) + xTiO(2), where x = 0.5 mol%, was determined using a UV-Vis spectrophotometer attached to a Reflectance Spectroscopy Accessory for powdered samples. The samples was prepared using the solid-state route and sintered at temperatures from 1140 to 1260 °C for 45 and 90 minutes. E(g) was observed to decrease with an increase of sintering temperature. XRD analysis indicated hexagonal ZnO and few small peaks of intergranular layers of secondary phases. The relative density of the sintered ceramics decreased and the average grain size increased with the increase of sintering temperature.     

Potential interference and rain attenuation at 21.4–22 GHz downlink broadcasting satellite signals

World Radio Conference WRC-1992 has allocated the frequency band 21.4–22.0?GHz to regions 1 and 3 to be utilised to carry direct broadcasting satellite (DBS) services. This high-frequency band is more susceptible to rain attenuation, leading to degradation of the signal quality. Moreover, this frequency band is assigned to two different services, i.e. satellite broadcasting and fixed mobile services at the same regions; hence, the impact of intersystem interference in a depredated signal is a critical issue in the DBS receiver. In this study, the effects of rain attenuation on the DBS downlink signals as well as the impact of the potential interference on the reception quality will be estimated. An interference scenario will be introduced to investigate the system performance in both propagation mechanisms of clear-sky and rain conditions.     

Synthesis of a Potential Tumor Imaging Agent by Oxidative Radioiodination of Aspirin and Its Preclinical Study

Radiochemistry - Aspirin, one of nonsteroidal anti-inflammatory analgesic drugs, was labeled with 125I with a labeling yield of 85.5% under the following conditions: pH 9, 100 mg of the substrate,...     

Blind Decoding of Massive MIMO Uplink Systems Based on the Higher Order Cumulants

In a developing country like India, there is an exponential rise in population nutrition requirement. To meet up with both the ends, the agricultural techniques should be perfected for optimal yield and quality. Irrigation and soil property monitoring system using sensors can be automated and operated wirelessly to achieve optimal water supply control and surveillance. The objective of this paper, is to automate the whole wireless sensor network (WSN) system with a control over water pumps and dripper valves. The humidity, temperature and pH sensor’s percepts provide a feedback, to control the water content of the soil. The system has an low-cost and energy reliable ZigBee for sensor data transformation, high-range GPRS system for data storing and analysis, and the whole system is powered by Solar panels which makes it self-sustainable. Customizable options for different crop with different requirements make it a versatile WSN system for automated irrigation based water management.