ON A GENERALIZATION OF LINEAR POSITIVE OPERATORS FOR FUNCTIONS OF GROUTH 2^(x+y) IN TWO DIMENSIONS (x,y)

In this paper, we introduce a generalization of linear positive operators...

The Effect of Hole Size and Location on Spring-back Phenomenon in Sheet Metal Bending

في عملية تشكيل الصفائح المعدنية يتم إجبار المشغولة على إتخاذ شكل وأبعاد الفجوة الموجوده في القالب وذلك عن طريق مكبس صلد وبعد ان تتم عملية التشكيل وإزالة المكبس يلاحظ حدوث رجوع نسبي للابعاد عن الابعاد الحقيقية لفجوة القالب وقيمة هذا الرجوع تعتمد على كلا من نسبة التشويه المرن ونسبة التشويه اللدن، وتسمى ظاهرة التخلص من التشويه بظاهرة الرجوعية. تعتبر الرجوعية واحده من أهم العيوب في عمليات التشكيل ويظهر ذلك التأثير واضحا عندما يرداد تجميع تلك الصفائج مع الاجزاء الاخرى     وذلك لعدم دقة الابعاد النهائية. وقد تم انجاز الكثير من البحوث العلمية لتقليل من تأثير تكلك الظاهره خللا عملية حني الصفائح المعدنية المتماثلة في الشكل والمتناظره في الابعاد والغير حاويه على تجاويف او ثقوب، في حين إن واقع الحال هنالك الكثير من المنتجات يتم خلالها حني صفائحا حاويةً على ثقوب مسبقة. ولمعرفة تأثير كل من حجم الثقب وموقعه تم في هذا البحث اجراء عمليات الحني على صفائح معدنية من معدن الحديد المنخفض الكاربون بالابعاد (200 x 50 x 0.75) ملم وقد تم عمل ثقب نافذ في كل صفيحه وحسب الاقطار (5 , 10 , 15 , 20 , 25) ملم ثم تم تغيير موقع كل ثقب حول خط عمودي على طول كل صفيحة. وقد تم إستخدام برنامج تصميم التجارب (DOE) لمعرفة قيمة الرجوعية عند حني الصفائج المثقوبه في قالب على شكل حرف V بعمق 12mm و19mm عن طريق إجراء (78) إختباراً عمليا وتغذية نتائج تلك الاختبارات كمدخلات لبرنامج (DOE)لكي يتم تحديد التاثير المثالي بين حجم الثقب وموقعه الذي يعطي الحد الأدنى من تأثير الرجوعية. وقد تم بناء نموذجين تربيعيين للقالب بعمقين كمدخلات. وقد تبين أن كلا من حجم الثقب وموقعه كان لهما تأثير كبير على قيمة الرجوعيه. تم الحصول على القيم المثلى من الرجوعيه لكلا العمقين. تم التوصل إلى توافق جيد مابين قيمة الرجوعيه التجريبية ووقيمتها النظرية مع نسبة خطأ 0.286 %.  لعمق القالب 12 mm و0.037    % للعمق 19mm. وأخيرا، تم التوصل إلى أن قيمة الرجوعيه قد انخفضت بنسبة 6.47 % عند استخدام القالب ذو عمق 19mm بالمقارنة مع عمق القالب 12 mm.Due to the sheet metal bending process, the sheet of metal is forced to take the shape of the die cavity by a rigid punch to fit it with that cavity dimensions, but when the punch is removed, the elastic deformation will be released and only the plastic deformation will be remained, this release of the elastic deformation caused the phenomenon which is called springback defect.   The springback is one of the defects that happen in the forming of sheet metal and its effect appears clearly in the assembly processes because of the change in final product dimensions. More researches were done to reduce the effect of this phenomenon on the uniform and symmetry sheets, but in reality, the products which are made by bending the sheet metal may contain holes before its forming. Therefore, in this research, the effect of the hole size and its center locations on the springback behavior and its value was specified for carbon steel material with (200 x 50 x0.75) mm, which and was drilled with different holes diameters (5, 10, 15, 20, 25) mm, and then the location of each hole was changed about the perpendicular centerline of each sheet . Design of Experiment Software DOE was used to predict the value of springback for two V-shaped dies with forming depth of 12 and 19 mm by conducting 78 experimental tests and feeding its results as an input to DOE to select the perfect mix between hole size and its position which gives the minimum springback effect. Two mathematical quadratic models were built for the two die depths in terms of use input parameters. It was found that both hole size and its location had great impact on the springback. The optimum values of springback were obtained for the two die depths. Good agreement was found between the experimental and theoretical springback with a maximum error of 0.286 % for 12 mm die depth and 0.037 % for 19 mm die depth. Finally, it was concluded that the springback value was reduced by 6.47 % when using 19 mm die depth in comparison with 12 mm depth

Antimicrobial Susceptibility Pattern of Extended Spectrum Betalactamase Producers In Gram-Negative Urogenital Isolates In Kano, Nigeria

The emergence of resistant strains of urogenital extended spectrum beta-lactamase producing isolates has presented a serious set back in the treatment option for urogenital tract infection. Emergence and spread of these strains resulted in treatment failure and disease complications. This study was aimed to determine the prevalence of ESBL producers in Gram-negative urogenital isolates and their susceptibility to 10 selected antimicrobial agents [aztreonam, cefoxitin cefepime, levofloxacin, ciprofloxacin, kanamycin, gentamicin, streptomycin, clarithromycin and erythromycin.]. A total of 500 isolates of Escherichia coli, Proteus mirabilis, Proteus vulgaris, Klebsiella pneumoniae, Klebsiella aerogenes, and Pseudomonas aeruginosa were collected from Microbiology Department of Aminu Kano Teaching Hospital (AKTH), Kano. The isolates were tested against third generation cephalosporins using Clinical Laboratory Standard Institute (CLSI) recommended, WHO modified Kirby-Bauer disc diffusion method. Isolates with reduced susceptibility to cefpodoxime, cefpotaxime and ceftriaxone were considered to be a possible ESBL producers and were confirmed using double disc synergy method. The number of ESBL producers in 500 urogenital gram negative isolates was found to be 77/500 (15.4%). Out of the 77 ESBL producing urogenital isolates 47 (61%) isolates which include E. coli, (33, 70%), K. aerogene (3, 6%), K. pneumoniae (6, 13%), P. mirabilis (9%) and P. aeruginosa (2%) were subjected to antimicrobial susceptibility test using CLSI recommended, WHO modified Kirby Bauer disc diffusion method. Zone diameters were interpreted using European Committee on Antimicrobial Susceptibility Testing breakpoint tables for interpretation of zone diameters. The overall result demonstrates high resistance rate (≥60%) to the selected antibiotics. The isolates were found to be more susceptible to Cefoxitin (40%), and Cefepime (38%); followed by Kanamycin (32%), Levofloxacin (28%), and Ciprofloxacin (28%). With Gentamicin (16%) Clarithromycin (11%), Streptomycin (9%), Aztreonam (4%) and Erythromycin (2%), showing low antimicrobial activity against the isolates. The result of this study shows that multidrug resistant ESBLs producing strains are present among urogenital bacterial pathogens in Kano. It is recommended that urogenital ESBLs isolates treatment option be based on antimicrobial susceptibility results

User interface design for mobile-based sexual health interventions for young people: Design recommendations from a qualitative study on an online Chlamydia clinical care pathway

Background: The increasing pervasiveness of mobile technologies has given potential to transform healthcare by facilitating clinical management using software applications. These technologies may provide valuable tools in sexual health care and potentially overcome existing practical and cultural barriers to routine testing for sexually transmitted infections. In order to inform the design of a mobile health application for STIs that supports self-testing and self-management by linking diagnosis with online care pathways, we aimed to identify the dimensions and range of preferences for user interface design features among young people. Methods: Nine focus group discussions were conducted (n=49) with two age-stratified samples (16 to 18 and 19 to 24 year olds) of young people from Further Education colleges and Higher Education establishments. Discussions explored young people's views with regard to: the software interface; the presentation of information; and the ordering of interaction steps. Discussions were audio recorded and transcribed verbatim. Interview transcripts were analysed using thematic analysis. Results: Four over-arching themes emerged: privacy and security; credibility; user journey support; and the task-technology-context fit. From these themes, 20 user interface design recommendations for mobile health applications are proposed. For participants, although privacy was a major concern, security was not perceived as a major potential barrier as participants were generally unaware of potential security threats and inherently trusted new technology. Customisation also emerged as a key design preference to increase attractiveness and acceptability. Conclusions: Considerable effort should be focused on designing healthcare applications from the patient's perspective to maximise acceptability. The design recommendations proposed in this paper provide a valuable point of reference for the health design community to inform development of mobile-based health interventions for the diagnosis and treatment of a number of other conditions for this target group, while stimulating conversation across multidisciplinary communities

Building a Reliable Steganography System Using Random Key in a spatial Domain of Image

With time progress importance of hiding information become more and more and all steganography applications is like computer games between hiding and extracting data, or like thieves and police men always thieve hides from police men in different ways to keep him out of prison. The sender always hides information in new way in order not to be understood by the attackers and only the authorized receiver can open the hiding message. This paper explores our proposed random method in detail, how chooses locations of pixel in randomly , how to choose a random bit to hide information in the chosen pixel, how it different from other approaches, how applying information hiding criteria on the proposed project, and attempts to test out in code, and in practice, through example

Web application authentication using ZKP and novel 6D chaotic system

Text password has long been a dominant approach to user authentication used by a huge quantity of Internet services. Web applications are now widely used for the implementation of a range of significant services. The securing of such applications has thus become a significant process. Currently the frequent use of passwords and the need for them make them more vulnerable to theft or guesswork. In the proposed research, the researcher designed an algorithm that has the ability to perform registration or to access web applications safely. The researcher designed an algorithm in the proposed research, which has the ability to securely perform registration or access web applications. The proposed idea based on the notion of Zero-knowledge proof. A complex generation of random number initiated by proposed novel 6D-Hyper chaotic system. The bottom line is that both parties (web application, user), have a secret number. These two numbers used to do the process of registration without requiring a password. Results from the research showed the importance of the proposed method by which the keys were managed and distributed in a safe and effective way

Evaluation of gingival biotype and recession following non-surgical periodontal treatment using 3-dimensional scan methods

The study evaluated the position of gingival margins in anterior teeth using clinical and 3-dimensional (3D) optical scanning method among patients subjected to nonsurgical periodontal treatment (NSPT). A single arm, longitudinal study was undertaken at the Archway Dental Center, University of Manchester, UK. History and clinical examination were done. Gingival recession, attachment loss (AL), and periodontal probing depth (PD) were recorded at baseline and 12-weeks follow-up. NSPT was done using hand and ultrasonic instruments. Impressions were made, the resultant gypsum models were scanned to generate 3D images. The change in the gingival level and thickness of facial gingiva were assessed. Out of eight patients recruited, three were lost to follow up. The 3D scan showed a poor correlation with the clinical assessment of gingival recession in anterior teeth following NSPT (r=-0.0089). Recession did not improve after NSPT (p≤ 0.20)