Time-dependent behaviour of micro-tunneling construction in Queenston shale

The Queenston shale among other shales from southern Ontario exhibits time-dependent deformation behaviour. This behaviour is manifested in the form of volume increase which can cause damages to the hosted underground structures. The time-dependent deformation of rocks can cause cracks in the springline of tunnels, wall inward movement, roof spalling and floor heave, which requires costly remedial measures. The expansion of the existing infrastructures in southern Ontario requires construction techniques, such as micro-tunneling to build new tunnels and pipelines under the existing structures with minimal impact to these structures and to the environment. However, adopting this technique in swelling rocks, such as the Queenston shale requires an evaluation of its feasibility and functionality prior to its application. Accordingly, a comprehensive study that included experimental and numerical investigations was conducted to evaluate the impact of lubricant fluids used in micro-tunneling applications on their time dependent behaviour. The experimental program evaluated the impact of water, bentonite and polymer solutions on the Queenston shale through: i) investigating the influence of lubricant fluids on the time-dependent deformation behaviour of the Queenston shale through performing free swell, semi-confined, and null swell tests on Queenston shale in these fluids, ii) investigating the impact of lubricant fluids on the strength of the Queenston shale utilizing the Brazilian, direct tension, unconfined compression, and triaxial compression tests, before and after soaking in lubricant fluids, and iii) investigating the depth of penetration of lubricant fluids and water into the Queenston shale. It was revealed that the impact of polymer solution was significant in reducing the time-dependent deformation of the Queenston shale compared to bentonite solution and water. The strength of the Queenston shale was remarkably decreased after their continuous exposure to water and lubricant fluids with minimal impact caused by polymer solution. The penetration of lubricant fluids was found smaller compared to water, and a relation was derived to compute the penetration depth of each fluid in Queenston shale with time. The numerical investigation comprised finite element parametric analyses using the derived tests results along with time-dependent deformation model employing computer program PLAXIS 2D. Different pipe diameter, pipe depth, in-situ stress ratio, and waiting time before final grouting were used in the analyses. Accordingly, micro-tunneling was found to be workable and feasible technique to construct tunnels and pipelines in the Queenston shale of southern Ontario. Recommendations to use the appropriate strength of the make concrete; waiting time and the most suitable depth for micro-tunneling applications are given. The results are envisioned to aid in determining whether or not micro-tunneling technique is a feasible construction technique for pipelines / tunnels in Queenston shale of southern Ontario

Improve Bounds of some Arithmetical Functions

نبين في هذا البحث استخدام دالة المعيار للحصول على بعض المعلومات عن القيد السفلي لدالة ريمان زيتا    بحيث  هذا الموضوع درس عميقا من قبل العالم هلبيردنك (انظر المصدر الاول). الحصول على قيد لداله ريمان زيتا في شريط الفترة الحقيقية        يكون من الصعب جدا وذلك للعديد من الاسباب التي تعود الى تصرفات تلك الداله في ذلك الشريط. الهدف من هذا البحث هو اثبات    له قيد سفلي دقيق عندما الجزء الحقيقي من   يكون جدا قريب من الخط 1.We show in this article the use of the norm function to get a new lower bound of Riemann-Zeta function  where.  This subject has been studied deeply by Hilberdink [HIL, 12]).  Getting a bound for the Riemann-Zeta function  in the critical strip is more challenging  for many reasons related to the behavior of the  Riemann-Zeta function in that strip. In the other words, the aim of this article  is to prove that  has a strict lower bound when the real part  is very closed to the line 1.  We state this in the  main theorem of this paper

Preparation and Characterization of Antimicrobial PVA/ZnO Nanocomposite for Biomaterial Applications

السيطرة على العدوى الميكروبية هي قضية بالغة الأهمية في المستشفيات. البوليمرات المضادة للميكروبات هي أنواع جديدة من المعقمات، والتي يمكن استخدامها كبدائل للمطهرات في بعض الأحيان. تم في هذا البحث تكوين متراكب نانوي من بوليمر بولي فنيل الكحول مع الجسيمات النانوية لأوكسيد الزنك بحجم (90 نانو متر) بطريقة ذوبان المنصهر. حبيبيات أوكسيد الزنك النانوية تم تعديل سطحها بواسطة مادة الداي مثيل سلفوكسايد (DMSO) وذلك للحصول تشتيت جيد ضمن المادة الأساس ومن ثم تقليل التكتل. والغرض من هذه الدراسة هو تحديد النشاط المضاد للميكروبات للمادة المركبة النانوية (بولي فنيل الكحول\اوكسيد الزنك) ضد بكتيريا غرام-موجب (Pseudomonas aeruginosa;Escherichia coli) وغرام-سالبة (Staphylococcus aureus;Staphylococcus epidermidis)    والفطريات Candida. تم دراسة تأثير تركيز وحجم الجسيمات على النشاط المضاد للبكتيريا لجسيمات أوكسيد الزنك النانوية باستخدام اختبار اقل تركيز يثبط البكتيريا (MIC) وتم دراسة النشاط المضاد للميكروبات للمادة المركبة بواسطة اختبار Agar well diffusion. وأظهرت النتائج أن النشاط المضاد للميكروبات من الجسيمات ZnO مع PVA يزداد مع انخفاض حجم الجسيمات وزيادة تركيز .ZnO.Control of microbial infections is a highly important issue in hospitals. Antimicrobial polymers are new kinds of antiseptics, which can be used as alternatives to disinfectants in sometimes. Zinc oxide nanoparticles (90 nm) with polyvinyl-alcohol (PVA) generated by melting route. ZnO NPs was modified by dimethyl sulfoxide (DMSO) to get on uniform distribution within the matrix and then reduce agglomeration. The purpose of this study is to determine the antimicrobial activity of PVA ̸ ZnO nanoparticles against Gram-negative bacteria (Pseudomonas aeruginosa; Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus; Staphylococcus epidermidis) and fungi (Candida albicans,). The effects of concentration and particle size on the antibacterial activity of ZnO nanoparticles was studied using minimum inhibitory concentration (MIC) test and the antimicrobial activity of PVA/ZnO nanocomposite was studied using agar well diffusion method. Results showed that the antimicrobial activity of ZnO nanoparticles with PVA increased with decreasing particle size and increasing concentration of ZnO NPs. Results showed that all microbes were fully inhibited at 3.7 μg / ml concentration for ZnO NPs, but activity against bacteria was not observed at 1.8 μm / ml

Experimental and Numerical Evaluation of the Fundamental Natural ‎Frequency of a Spherical Core Sandwich Structure.‎

  مقدمة: الهدف من هذه الدراسة هو التحقق من تأثير متغيرات العوامل الجيومترية عدديا وتجريبيا على خاصية التردد الطبيعي لألواح ساندويج ذات قلب كروي . هذه الالواح مصنعة بطريقة أبتكارية بواسطة أستخدام شمع النحت التعليمي . العوامل الجيومترية هي قطر الكرة وسمك الوجه والمسافة بين الكرات. طرق العمل: طبقا لمنهجية استجابة السطوح - تصميم التجارب تم تصميم 15 عينة وفق طريقة بوكس-بيهنكن  وأعتمادا على الظروف التجريبية لحدود قيم كل متغير. المادة الأساس في الصب هي البوليستر الغير مشبع . الطول الفعال لجميع العينات المصنعة كان ثابتا بقيمة 20 سم. تم تقييم التردد الطبيعي عدديا باستخدام نظرية العناصر المحددة وعمليا باستخدام الاختبار المشروط  وحساب الفارق بينهما. تأثير المتغيرات الجيومترية تم تحليلها بأستخدام نظرية تحليل التباين الإحصائية. الأستنتاجات: بينت هذه الدراسة فهما جيدا لتأثير المتغيرات الجيومترية لألواح ساندويج ذات قلب كروي عل خاصية التردد الطبيعي. النتائج العملية والعددية بينت  فارقا في القيم لم يتجاوز 15% أما النتائج الإحصائية فبينت ان المسافة بين الكرات كان لها تاثير كبير جدا ورئيسي على جميع المتغيرات الجيومترية الأخرى. سمك الوجه وقطر الكرة كان لهما تاثير أقل وفقا الى تلك البيانات.Background: This study investigates the effect of the variation of the geometrical factors on the fundamental natural frequency of the novel spherical core sandwich structure numerically and experimentally.  These novel structure are made up by using carving wax. The geometrical factors are diameter of sphere, skin thickness and spacing between spheres. Materials and Methods: Fifteen specimens according to response surface methodology - design of experiments  and using Box-Behnken method were manufactured from unsaturated polyester material with different geometry while maintaining a 20 cm effective length. The fundamental natural frequency was evaluated according to two methods numerically by using finite element analysis and experimentally by using the modal test. ANOVA statistical analysis was used to evaluate the effect of the geometrical factors on the natural frequency Results: The results show that the discrepancy between these methods was less than 15%. The spacing between the spheres was a dominant factor that influence the fundamental natural frequency. The sphere diameter is a less dominant factor while the skin thickness has a minor influence on the fundamental natural frequency of the spherical core sandwich structure. Conclusions: This study provides a better understanding of the influence of the geometrical properties of the structure on the fundamental natural frequency. The most influential factor on the fundamental natural frequency is the spacing between the spheres while The diameter of the sphere has less influence, while the skin thickness has a minor effect on the fundamental natural frequency

Numerical and Experimental Investigation of Nano zinc Oxide's Effect on the Mechanical Properties of Chloroprene and Natural Rubber (CR/NR) Composites

Nanocomposites, especially natural rubber (NR), have been extensively studied for their unique features and superior performance in tire applications. The present research investigated the impact of zinc oxide nanoparticles (ZnO) on the performance of typical rotary machine seals made of chloroprene rubber / natural rubber (CR/NR) composites. An ordinary standard rubber two-roll mill and hydraulic press were used to prepare high-temperature vulcanized CR/NR samples filled with ZnO nanoparticles. Tensile strength, tear resistance, abrasion resistance, resilience, and hardness were measured to determine the effects of nanoparticles on these physical and mechanical properties. Based on the various hyperelastic modeling schemes, enhancement in multiple characteristics of the control sample, such as overhaul properties, was observed. Furthermore, results show that increasing nanoparticle content in the vulcanisates increased the physicomechanical characteristics, such as hardness, resilience, tensile strength, and elastic Modulus at 200% strain. Moreover, hyperelastic analytical modeling shows that the differences with experimental results are less than 5%

Role of sclrostin (SOST) to predisposing for osteoporosis in β- thalassemia major patients

Sclrostin is a biomarker interrupted in bone resorption process by binding to LRP5 and/or LRP6 family, and prevent Wingless-type signaling (Wnt)  which is important to both bone development and the maintain of bone mass. Sixty (60) patients with thalassemia major were enrolled from the period 2/5/2021 to 1/9/2021 in summer to assessment role of sclrostin to predisposing for osteoporosis in β-thalassemia major patients (β-TM). Patients ages were from (2-40 year) males and females they divided to children and adults had osteoporosis and/or osteopenia."All patients diagnosed by Hb electrophoresis and were receiving regular blood transfusions for anemia and chelation therapy for prevention of iron overload related complications. Detailed history and examination including height and weight were recorded on pre-designed questionnaire and blood samples were taken for measurement of serum"sclrostin level. The results showed  non-significant differences (P˃0.05)  of serum sclerostin (SOST) concentration between osteoporosis of beta thalassemia patients (β-TM) and osteopenia of beta thalassemia patients for both gender, but appeared increased significant (P˃0.05) in male adults of osteopenia with progressive aged

Effect of novolac nanoparticles additions on specific gravity of NBR/CR blends

In this article, novolac nanoparticles with different weight fraction (0-40) wt.% were added to NBR/CR blends and investigate the effect of these additions on the specific gravity of rubber blend. The results obtained shown that the novolac nanoparticles works on increasing the specific gravity of NBR/CR blends, and specific gravity ratio increases with increased novolac nanoparticles percentage

Numerical modeling of time-dependent deformation and induced stresses in concrete pipes constructed in Queenston shale using micro-tunneling technique

Effects of time-dependent deformation (TDD) on a tunnel constructed using the micro-tunneling technique in Queenston shale (QS) are investigated employing the finite element method. The TDD and strength parameters of the QS were measured from tests conducted on QS specimens soaked in water and lubricant fluids (LFs) used in micro-tunneling such as bentonite and polymer solutions. The numerical model was verified using the results of TDD tests performed on QS samples, field measurements of some documented projects, and the closed-form solutions to circular tunnels in swelling rock. The verified model was then employed to conduct a parametric study considering important micro-tunneling design parameters, such as depth and diameter of the tunnel, in situ stress ratio (Ko), and the time lapse prior to replacing LFs with permanent cement grout around the tunnel. It was revealed that the time lapse plays a vital role in controlling deformations and associated stresses developed in the tunnel lining. The critical case of a pipe or tunnel in which the maximum tensile stress develops at its springline occurs when it is constructed at shallow depths in the QS layer. The results of the parametric study were used to suggest recommendations for the construction of tunnels in QS employing micro-tunneling. Keywords: Numerical model, Micro-tunneling, Queenston shale (QS), Lubricant fluids (LFs