MODELLING AND SIMULATION OF A SOLAR POND-GREENHOUSE SYSTEM

To maintain prescribed temperature levels inside a greenhouse for plant growth, diesel fuel was used in the past, however due to increased fuel prices, greenhouse heating expenses have reached such levels that conservation and alternative methods are becoming attractive. Such alternatives include solar passive heating, and solar ponds.

Although there are several methods of heating a greenhouse, the present paper focused on the potential use of solar ponds as a primary heating system. The possibility of supplying all heating requirements of a greenhouse through a solar pond has been theoretically investigated.

Models to simulate both the solar pond and the greenhouse thermal behavior were developed based on conventional energy balance equations. Numerical techniques were used to estimate daily greenhouse heating and cooling requirements and the performance of the solar pond as a heating system.     

DETERMINING THE MECHANICAL PROPERTIES OF CHERRY TOMATO VARIETIES FOR HANDLING

Tomatoes, like other vegetables, are susceptible to different kinds of damage during and after harvest. Such damage is a major cause of quality loss in fruit. In order to reduce these losses, it is necessary to know the mechanical properties of the fruit. These mechanical properties of tomato were determined in terms of average rupture force, deformation energy, specific deformation and modulus of elasticity. Variance analysis was carried out on three tomato varieties, and the difference between the mean values was investigated by the least significant difference test. Mean values were represented with the standard error.
The results provide useful data to be used by engineers in the design of sorting, grading and packing machines, equipment for loading and unloading, storage structures, drying equipment, (all postharvest operations), harvesting machines and conveyors.

PRACTICAL APPLICATIONS

Our aim for this research is to get useful data for engineers in the design of sorting, grading and packing machines, equipment for loading and unloading, storage structures, drying equipment, harvesting machines and conveyors.     

AN EFFICIENT DNA-EXTRACTION PROTOCOL FOR NUT SEEDS

Establishing genetic origin of food products allows verification of the authenticity of valuable foods and discourages adulteration with material of lower cost and value. This is particularly important for food products that have obtained European recognition. The use of molecular markers could be a solution for species and cultivar identification and for the genetic traceability. The development of efficient DNA-extraction protocols is an essential step for the procedure. In this work, a method for total DNA isolation was developed for hazelnut, almond and walnut seeds. The efficiency and reliability of the method was tested by assessing quantity and quality of the extracted DNA, and by Polymerase Chain Reaction (PCR) amplification, using two decamer primers and three universal primer pairs designed on the chloroplast DNA. The success of amplifications confirmed the presence of both nuclear and chloroplast DNA in the extracted sample.

PRACTICAL APPLICATIONS

Cultivar identification of nuts, based on morphological traits only, is often difficult, and adulterations with seeds of lower cost and quality are easy, above all when they are sold as shelled kernel, as is common for hazelnut. The genetic identification of cultivars is nowadays a routine practice, because of the development of DNA-typing techniques based on molecular markers. An efficient DNA-extraction procedure for hazelnut, almond and walnut seeds is a preliminary step required for enabling the recognition of the cultivar of origin of the nuts and fighting commercial frauds. It will also be useful in marker-assisted selection, applied in breeding.     

Experimental and theoretical characterization of miniature coplanar waveguide shunt stubs patterned on the centre conductor

Several new designs are presented for coplanar waveguide (CPW) open- and short-ended shunt stubs patterned on the centre conductor. Unlike conventional stubs which are patterned on the ground plane, the new designs are more compact and less radiative. They also provide more flexibility to the design of CPW circuits. The performance of the new stubs is verified by experiment and simulation and is found to be very satisfactory over the large frequency band 0–50GHz. Experimental results obtained for a conventional and new stub show that the new stub is less radiative.     

基于MOSFET PDE模型的射频电路周期稳态分析

研究了基于 MOSFET PDE模型的射频电路周期稳态分析有效算法 :通过恰当的系统解耦、松弛迭代和边值问题求解等方法避免了复杂的 PDE周期稳态分析 ,较好地解决了基于 MOSFET PDE模型的射频电路周期稳态分析的计算效率问题。采用该算法仿真典型的 C类功率放大器得到电流波形和工业界公认标准器件仿真器 MEDICI瞬态模拟得到电流波形比较 ,显示出很好的一致性。     

基于类别分布差异和特征熵的维吾尔语文本特征选择

文本特征选择是在文本自动分类中最重要的一个环节。为了更好地解决维吾尔文文本分类中特征空间的高维性和文档表示向量的稀疏性问题, 提出一种基于特征的类别分布差异和信息熵的维吾尔文文本特征选择方法。该方法不仅要考虑特征在类别间的分布情况, 而且也要考虑特征在类别内的分布情况。采用本方法对维吾尔文文本语料进行了分类实验, 并与一些传统的特征选择方法进行了比较。从结果来看, 本方法在所选特征数更少的情况下, 达到了比其他方法更高的分类MacroF1值853%, 比传统的IG和CHI等方法在MacroF1值上分别高出了43%和61%。     

QUALITY INSPECTION OF BAKERY PRODUCTS USING A COLOR-BASED MACHINE VISION SYSTEM

Muffins were evaluated for color by visual examination and by development of a machine‐reading system coupled with discriminant analysis of the data acquired. A classification algorithm separated light from dark‐colored muffins. The system's precision was assessed by evaluating the color of 4 cm diameter muffins pregraded prior to the evaluation of color and without pregrading. Applied to 200 samples, the automated system was able to correctly classify 96% of the pregraded and 79% of the ungraded muffins. The algorithm procedure was able to classify muffins at an accuracy level better than 88% in most cases whereas quality decisions among inspectors varied by 20 to 30%. Critical to precision by the machine‐read procedure was control of the illumination.     

Densification and dielectric properties of SrO–Al2O3–B2O3 ceramic bodies

The influence of SrO (0·0–5·0 wt%) on partial substitution of alpha alumina (corundum) in ceramic composition (95 Al₂O₃–5B₂O₃) have been studied by co-precipitated process and their phase composition, microstructure, microchemistry and microwave dielectric properties were studied. Phase composition was revealed by XRD, while microstructure and microchemistry were investigated by electron-probe microanalysis (EPMA). The dielectric properties by means of dielectric constant (ε _r ), quality factor (Q × f) and temperature coefficient of resonant frequency (τ _f ) were measured in the microwave frequency region using a network analyser by the resonance method. The addition of B₂O₃ and SrO significantly reduced the sintering temperature of alumina ceramic bodies to 1600 °C with optimum density (∼ 4g/cm³) as compared with pure alumina powders recycled from Al dross (3·55g/cm³ sintered at 1700 °C).