We describe the use of porous silicon fabrication technique for fabricating non-manhattan structures in silicon using wet etching. The fabrication method is simple to set up, economical and produces smooth etched surface. A solid source diffusion of N++ in a P type wafer with low stress thermally grown silicon nitride is used as a masking layer. Comparison of porous silicon etches with wafers solid source diffusion and implanted diffusion is presented. The result show that areas where a solid source diffusion is used form an etch angle of 70-80°, however using an implanted diffusion the etch angle is closer to 90°. The selectivity of the etch during porous silicon fabrication using any of the above two as masking layer results in fabrication of high aspect ratio non-manhattan structures. These structures since are wet etched do not have surface roughness and can be used for optical applications.
ORIGINAL RESEARCH ARTICLE | Oct. 17, 2019
A New Model for Arabic Text Clustering by Word Embedding and Arabic Word Net
Nehad M. Abdel Rahman Ibrahim
Page no 401-406
A major challenge in article clustering is high dimensionality, because this will affect directly to the accuracy. However, it is becoming more important due to the huge textual information available online. In this paper, we proposed an Arabic word net dictionary to extract, select and reduce the features. Additionally, we use the embedding Word2Vector model as feature weighting technique. Finally, for the clustering uses the hierarchy clustering. Our methods are using the Arabic word net dictionary with word embedding, additionally by using the discretization. This method are effective and can enhance improve the accuracy of clustering, which shown in our experimental results.
ORIGINAL RESEARCH ARTICLE | Oct. 21, 2019
Performance Evaluation of Symmetric Data Encryption Algorithms: AES and Blowfish
Bello Alhaji Buhari, Afolayan Ayodele Obiniyi, Kissinger Sunday, Sirajo Shehu
Page no 407-414
People are transferring large amount of data that are critical and consume large amount of time through the Internet such as email, banking transaction and online purchase. But due to high exposure they are susceptible to being heavily attacked or become attractive targets for attackers. This can be solved by using a modern phenomenon called symmetric encryption. Symmetric encryption is used to ensure that information is hidden from anyone for whom it is not intended. This research conducted a performance evaluation of symmetric data encryption algorithms namely Advanced Encryption Standard (AES) and Blowfish. The evaluation is done for four different data types: image data type, audio data types, video data types and textual file data types. The performance evaluation metrics are encryption time and throughput. The prototype is developed using JAVA, compiled using the Netbeans IDE7.1.2 with default settings in jdk 7.1 development kit. Results obtained from this evaluation indicated that blowfish is more efficient than AES. But for Blowfish the encryption time sometime decreases with the increase in data size. This can be attributed to the fact that Blowfish uses 126, 192 or 256 key sizes.
ORIGINAL RESEARCH ARTICLE | Oct. 25, 2019
Santos Dumont Airport: Civil Aviation in Rio de Janeiro, Brazil
Murillo de Oliveira Dias
Page no 418-421
In 2019, Santos Dumont Airport (SDU) completed 83 years of existence. The first civil transportation airport in Brazil was inaugurated on November 1936, while Rio de Janeiro was the Brazilian capital, two kilometers from the downtown area. To date, 29 thousand passengers are transported per day, approximately ten million per year, the second in public transportation in Rio de Janeiro, and the sixth Brazilian airport. On September 2019, SDU airport re-opened the two airport runways, closed for maintenance since August 12. Key findings pointed SDU airport important for regional flights in Rio, where Galeão International Airport (GIG) operates international flights. Also, despite the Brazilian capital has been changed from Rio to Brasilia, in 1961, SDU Airport, nevertheless, kept increasing civil transportation rates, due to its strategical location, in front of Guanabara Bay. Analysis of civil aviation in Brazil and worldwide, and discussion complete the present article.
ORIGINAL RESEARCH ARTICLE | Oct. 30, 2019
The Effectiveness of Shading Devices in Qatar University Campus
Asmaa Saleh Al-Mohannadi, Raffaello Furlan
Page no 428-446
The research study investigates the effectiveness of solar management techniques on the outdoor thermal comfort in hot, arid climates within the context of higher educational facilities. Qatar University in Doha, State of Qatar, is establishing the contextual unit of analysis as it provides a case study for urban planning and design within an educational environment. The campus has dynamic outdoor spaces that have been treated using urban strategies and techniques to create the most desirable environment for its vast range of users including students, faculty and staff members. The aim of the study is to assess the effectiveness of the current solar management techniques at Qatar University campus based on user’s satisfaction. Therefore, the focused scope of analysis is targeting the shading devices that are found in the campus, which has been generally categorized as pedestrian shaded pathways with detached canopies and car parking shading structures. The thesis targets the following question: does the current shading devices on campus provide a satisfactory experience for users in addition to encouraging walkability and better utilization of outdoor spaces? By investigating the effectiveness of solar management techniques, it is possible to optimize the use of the current shading devices by relating their effectiveness to users’ satisfaction and thermal comfort. Based on the methodology of survey analysis, a sample of fifty questionnaires has been collected and analyzed with reference to the existing users of the campus. The survey questionnaire is reinforced by further direct impressionistic observation as a verifying methodology.
ORIGINAL RESEARCH ARTICLE | Oct. 27, 2019
Optimum Process Parameters Selection for Brinell Hardness Number of Natural Fiber Reinforced Composites Using Taguchi Method
Sk. Suzauddin Yusuf, Nurul Islam, Hasan Ali, Washim Akram, Abubakar Siddique
Page no 422-427
Now-a-days, natural fiber-reinforced polymer matrix composites have received large attention of the researchers in various applications. The properties of natural fiber composites to a large extent influenced by the type of fibers, treatment method, types of hardener and resin, and fabrication method. In the present study, the hardness behavior of sponge gourd, coir, and jute fiber reinforced thermosetting resin-based composite has been investigated experimentally. Natural fibers were treated with 5% NaOH solution by volume and hand lay-up technique was used to fabricate these composites. The Wt% (weight percentage) ratio of resin and hardener, Wt% of resin & hardener in composite, Wt% ratio of sponge gourd & jute, and Wt% ratio of sponge gourd & coir are considered as control factors which were optimized using Taguchi L9 orthogonal design of experiments. The optimal control factor combination for maximum Brinell hardness was found out and the predicted optimal value, obtained from Taguchi analysis, of Brinell hardness was confirmed by validation experiments. At last, the interactions between control factors or input parameters with Brinell hardness are revealed graphically by interaction plots.