Millimeter Wave Substrate Integrated Waveguide Antennas: Design and Fabrication Analysis

The paper presents a new concept in antenna design, whereby a photo-imageable thick-film process is used to integrate a waveguide antenna within a multilayer structure. This has yielded a very compact, high performance antenna working at high millimeter-wave (mm-wave) frequencies, with a high degree of repeatability and reliability in antenna construction. Theoretical and experimental results for 70 GHz mm-wave integrated antennas, fabricated using the new technique are presented. The antennas were formed from miniature slotted waveguide arrays using up to 18 layers of photo-imageable material. To enhance the electrical performance a novel folded waveguide array was also investigated. The fabrication process is analysed in detail and the critical issues involved in the fabrication cycle are discussed. The losses in the substrate integrated waveguide have been calculated. The performance of the new integrated antenna is compared to conventional metallic, air-filled waveguide antennas, and also to conventional microstrip antenna arrays operating at the same frequencies

A ‘computer tutor’ to assist children develop their narrative writing skills : conferencing with HARRY

The purpose of this study was to test the hypothesis that a computer tool can change the way children approach the task of writing and improve their writing performance. HARRY, a web-based computer tutor, provides a Vygotskian-like scaffolding of the knowledge transforming mature writing process and presents it to children individually in a conference situation. The effects of the computer tutor are analysed by comparing stories produced by three children of varied writing ability, who wrote a control and a HARRY assisted story, and by observing the children as they wrote. A control group also wrote two stories without receiving assistance for either story. The study's hypothesis was confirmed. With HARRY's assistance, the children wrote better stories and employed the revision process characteristic of mature writers. Vygotsky's work suggests that children will learn to adopt the mature approach from repeated use of the system and that the scaffolding should be reduced gradually. However, as the system relied upon the children's willingness to first request, then act upon the available guidance, the system would benefit from further development to ensure children interact sufficiently with HARRY

Neutron Activation Analysis (NAA) of Senna occidentalis Linn

Senna occidentalis Linn was subjected to neutron activation analysis (NAA) in order to assess its major, minor, trace and ultra-trace contents. The results indicated that Al, Ca, Fe, Na and K have the highest concentration followed by Mn, Zn and Rb while Co, Rb, La, Sc, Sm and Th were in traces. The presence of toxic metals (such as As) in the plant at low levels and absence of others (e.g Cd and Pb) indicates that the plant can be consumed but bearing in mind that long consumption of the plant may lead to their bioaccumulation. The pattern of bioaccumulation of the elements did not follow any particular trend among the different parts of the plant. Key words: Senna occidentalis Linn and NAA

Phytochemical and proximate analysis of Aspillia kotschyi (Sch. bipex, hochst) Oliv

The phytochemical and proximate composition of Aspillia Kotschyi belonging to Compositae family which is commonly used as medicinal plant in Nigeria was determined on both the Methanolic and Petroleum spirit extracts of the plant material The Methanolic extract of the plant revealed the presence of carbohydrates, cardiac glyscosides, flavonoids, triterpene, and alkaloids. The Petroleum sprit extract showed the presence of only carbohydrates and alkaloid. Proximate composition analysis shows moisture content of 5.7%, total ash of 4.03%, crude protein 10.39%, fibre 9.06%,Fat value 0.83%,and Nitrogen free extract of 70.19%. The results of this study suggest some merit in the popular use of Aspillia kotschi in herbal medicine.Keywords: Aspillia kotschyi, Phytochemical, Proximate compositio

Assessing aspects of children's written grammar: automating the process

Teachers are expected to make regular assessments of pupils' writing, providing feedback about their strengths and weaknesses. If the computer could assist teachers in this task by effectively analysing the grammar element in children's writing, then the teacher's work load would be significantly reduced. A computer generated 'text analysis' of grammatical features would have the benefit of providing diagnostic information systematically and efficiently. Although text analysis is not new, it is generally restricted to applications aimed at adults. The development of a quantitative text analysis program, specifically geared to analysing children's writing was therefore considered profitable. This required an understanding of the development of children's writing abilities and the criteria of the National Curriculum levels of attainment for the Standard Assessment Tasks (SATs). Ten grammar features were selected for analysis. Stories reflecting the spread of attainment associated with the end of Key Stage 2 were analysed. The computer successfully distinguished positive and negative grammar features within these texts. Nevertheless, an assessment of qualitative genre details made by teachers will still be required, in order to provide a balanced assessment which includes all elements that contribute to effective writing

Improving children's written grammar and style: revising and editing with HARRY

Children usually improve their writing in response to teacher comments. HARRY is a computer tutor, designed to assist children improve their narrative writing, focusing particularly upon grammar and style. Providing assistance involved identifying aspects of grammar and style on which to concentrate, including ways to enable the computer to detect weaknesses and then present information concerning how to make improvements. HARRY delivers general, conversational style suggestions for how to revise a text during composition, followed by editing suggestions targeting specific grammar and style weaknesses detected in the text. Finally, spellings and technical errors are corrected in MS Word. Evaluating a writing intervention strategy is problematic, as paradoxically, attempts by children to improve texts, can result in a deterioration in some aspects of writing quality. Four case studies are presented to demonstrate the effects of the HARRY writing system upon children's grammar and style. Each child wrote a control and a HARRY assisted story. HARRY's effectiveness at improving written grammar and style is demonstrated through analyses made of the narratives by CHECK TEXT, a utility tool which calculates and interprets quantitative data. Separate analysis of each stage of the HARRY assisted stories reveals the idiosyncratic pattern of improvement exhibited by each child

Neutron Activation Analysis (NAA) and Energy Dispersive X-ray Fluorescence Analysis (EDXRF) on Corchorus tridens Linn

Analyses were carried on Corchorus tridens Linn in order to ascertain its elemental composition using neutron activation analysis (NAA) and energy dispersive x-ray fluorescence analysis (EDXRF). Nineteen (19) of the detected and determined elements were either essential, trace or heavy (Al, Ba, Br, Ca, Co, Cr, Cu, Fe, Hf, K, La, Mn, Na Rb, Sm, Sc, Th, V and Zn) while ten (10) others (As, Cs, Dy, Eu, Lu, Mg, Ta, Ti, U and Yb ) were found at below detection limit (BDL) levels. Variations of the elemental concentrations from the two techniques and the different parts of the plant were compared using student’s t – test and ANOVA test. Translocation factor of the elements and their concentrations in the different parts of the plant were compared with normal concentrations in plants and recommended daily allowance (RDA) values. It was found that for some of the elements, pattern of distribution is in the order of roots > stems > leaves while for others there is no regular pattern of distribution. Also, the amounts of certain essential elements in C. tridens L. show that the plant can serve as a means of supplementation of required minerals for man and his animals.Keywords: NAA, EDXRF, C. tridens L., translocation factor and bioaccumulatio

Microbiological Properties of Stored Freeze Dried Cow Milk Cheese and Soy Cheese

The microbiological properties of stored freeze dried cow milk cheese and soy cheese were investigated. Cow milk cheese and soy milk cheese were prepared using appropriate standard procedures. The microbial qualities of the stored freeze dried samples were determined using standard  methods as prescribed by Compendium of Methods for the Microbiological Examination of Foods and Bacteriological Analytical Manual. Data obtained were analyzed statistically to determine the effect of the packaging materials and storage duration on the microbial qualities of freeze dried cheese samples. Result of the microbial composition for the fresh cow milk and soy cheese for bacterial and fungi count are 3.00x103±0.01, 2.54x106±0.05 and 2.76x103±0.02, 2.60x106±0.10 while the result for the freeze dried cow milk and soy cheese before storage are 2.72x103±0.02, 2.35x106±0.30 and 2.54x103±0.03, 2.38x106±0.50. This indicates that all the packaging material types used have the ability to minimize the microbial growth of stored freeze dried cheese. Polythene film is recommended to be more suitable in terms of cost, availability, compactibility and weight. Keywords: cheese, freeze drying, microbial qualities, packaging materials

Antimicrobial activity of “Dutsen Dan Libya”

Dutsen dan Libya is a rock material used in traditional medicine for the treatment of a myriad of ailments like cold, fever, stomach disorder, diarrhea and Jaundice. To evaluate the scientific basis for the use of the rock, the antimicrobial activities of its water extract was studied against some common gram positive and gram negative bacteria and fungi. The antimicrobial activity of the aqueous extract was evaluated by determination of the diameter of zone of inhibition using the paper disk diffusion method. Results showed sensitivity to Pseudomonas aeruginosa, Streptococcus pyogenes, Staphylococcus aureus, Corynebacterium ulcerans, Klebsiella pneumoniae and Candida albicans. Bacillus subtilis, Salmonella typhi, Escherichia Coli and Neisseria gonorhoea were resistant. Studies on the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the rock-extract solution on the test organisms showed the lowest MIC at the dose level of 1.25mg/ml and MBC at the dose level of 2.50mg/ml respectively against Pseudomonas aeruginosa and Streptococcus pyogenes. The highest MIC (2.5 mg/ml) and MBC (5.00mg/ml) were exhibited against staphylococcus aureus, corynebacterium ulcerans, klebsiella pneumoniae and Candida albicans.KEYWORDS: Antimicrobial, Infectious disease, Pathogenic, Bacteria, Fung