Numerical Simulation of Temperatures Distribution and Residual Stresses of High Melting Temperature Polymer

This work predicts the effect of thermal load distribution in polymer melt inside a mold and a die during injection and extrusion processes respectively on the structure properties of final product. Transient thermal and structure models of solidification process for polycarbonate polymer melt in a steel mold and die are studied in this research. Thermal solution obtained according to solidify the melt from 300 to 30Cand Biot number of 16 and 112 respectively for the mold and from 300 to 30 Cand Biot number of 16 for die. Thermal conductivity, and shear and Young Modulus of polycarbonate are temperature depending. Bonded contact between the polycarbonate and the steel surfaces is suggested to transfer the thermal load. The temperatures distribution produces in thermal model importing as load and boundary conditions to solve the structure model. 3D mold and die are built to simulate the thermal and structure behavior using ANSYS 12.1 program. The results show that the temperatures and residual stresses decreases with the distance from the center to surfaces for the mold ,while for the die the temperatures and stresses decreases with the distance from the inlet to the outlet. The temperatures and stresses decreases with the time increasing for both mold and die. Also the thermal strain compatible with the temperatures distribution in the mold and the die. The total deformation concentrated at the left and right edge of polycarbonate in the mold, while starting in the center of the polymer at the outlet and then transfer to the entry of the die with the time increasing

Experimental and modeling study of hydrophobic associative polyacrylamide for enhanced oil recovery in carbonate reservoir

In this study, hydrophobic associative polyacrylamide (HAPAM) was used in conjunction with the chemical flooding technique in a low-permeability carbonates reservoir. To test the efficacy of the proposed method, both a model and an experiment were created. Experiments were run to compare the relative permeability (Kr) curves, oil recovery rates, and rheological, physical, aging time, and petrophysical features of brine water and polymer flooding in a core. The purpose of these tests was to show how HAPAM can be used to boost oil recovery. Computer Modelling Group (CMG), a simulator, was then used. An oil-and-brine (or HAPAM solution) grid in three dimensions (3D) was developed. The validity of the suggested simulator was established by comparing its results to those obtained from commercial software and from the majority of brine or polymer flooding experiments. The developed simulator was used to undertake additional research into the non-Newtonian flow of brine or polymer solution in porous media. The experimental consequences indicated that the polymer solution has a shear thinning viscosity curve and flow behavior index. Shear thinning, viscosity, shear resistance, aging time, density, surface tension, and interfacial tension, and the water wet relative permeability curve are all improved by the adding 1500 ppm HAPAM to brine water. Moreover, oil recovery was about 80%. There was a strong agreement between the results of the modeling study and the experiments

Polymer Biomedical Films

 الافلام المركبة لكل من بولي فنيل الكحول مع السليكا النانوية - اوكسيد الزنك النانوي. بولي مثيل ميثا اكريليت مع السليكا النانوية - اوكسيد الزنك النانوي- الكلوروفيل يتم تحضيرها باستخدام طريقة الصب ويتم تقييم تطبيقاتها الطبية. في هذه الدراسة السليكا النانوية واوكسيد الزنك النانوي تستخدم كماده ماله لتحسين الخواص البيولوجية والميكانيكه للأفلام المركبة. يتم اجراء العديد من الاختبارات على الافلام المركبة مثل مطياف الأشعة تحت الحمراء والفعالية المضادة للبكتريا واختبار الشد. اضهرت النتائج أن أوكسيد الزنك لديه نشاط مضاد للجراثيم ممتاز وهذا النشاط يزداد في الأفلام المركبة مع زيادة تركيز اوكسيد الزنك. الافلام المركبة البولي مثيل ميثا اكريليت اضهرت قوة شفاء أفضل من لأفلام المركبة لبولي فنيل الكحول. ولتجنب الشقوق على افلام بولي مثل ميثا اكريلت المنتجة، الكلوروفيل كصبغه طبيعية حيوية تضاف حيث انها تعمل كملدن وبذالك تزال الشقوق من الافلام المركبة. جميع الاختبارات الميكانيكية والفيزيائية تظهر ان لأفلام المركبة لبولي فنيل الكحول لها قيم اعلى من قيم الافلام المركبة البولي مثيل ميثا اكريليت وهذا يرجع الى حقيقة ان بولي فنيل الكحول يمكن ان يبني اواصر هيدروجينية مع اضافات اوكسيد الزنك النانوي او السليكا النانوية بينما بولي مثيل ميثا اكريليت لا يمتلك ميل لعمل اواصر هيدروجينية.Composite films of both Poly (vinyl alcohol)/nano silica-nano zinc oxide (PVA/SiO2- ZnO) and Poly (methyl methacrylate) / nano silica-nano zinc oxide -chlorophyll (PMMA/SiO2-ZnO-Ch) are prepared by using casting method and their medical applications are evaluated. In this study Nano, silica and Nano zinc oxide are used as filler with the following percentages of (1, 2 and 3) to improve the biological and mechanical properties of the composite films. Many tests are carried on the composite films such as Fourier transform infrared spectroscopy (FTIR), antibacterial activity, and tensile test. Their results show that zinc oxide has an excellent antibacterial activity and this activity increases in composite films with the increasing concentration of the zinc oxide .PMMA composite films show a better healing power than that of the PVA composite films. To avoid cracking on the produced PMMA film, chlorophyll as a bio natural pigment, is added it acts as a plasticizer and as a result it removes film stresses. All mechanical and physical tests show that the PVA composite has higher values than those of PMMA. This is due to the fact that PVA can build a hydrogen bond with ZnO or SiO2 additives while PMMA has no tendency for H-bonding. &nbsp

AN INVESTIGATION INTO THREE DIMENSIONAL TURBULENT FLOW OF NEWTONIAN LIQUID IN STIRRED TANKS MIXERS

The present work is concerned with the theoretical and experimental investigation of flow pattern of Newtonian fluid in liquid mixing process in stirred tank with flat blade impeller. A threedimensional model for mixing process was simulated. The effected parameters are rotation speed and impeller diameter. Continuity, momentum, and turbulent equations were solved by ANSYS package software 5.4 code with FLOTRAN/CFD based on Finite Element method. In the experimental work, two visualization methods are used in this work, the first method is the acidbase reaction visualization method and the second is the particle distribution visualization method. Different chemical materials were used in the first method, NaOH as a base, 2 4 H SO as acid and Methyl red as indicator, while polymer particles were used in the second method. The results of 3D model showed that the speed rotation directly affected the mixing zones, where the speed reduction by half decreasing the mixing zones approximately by half. Also the impeller diameter increasing clearly affected the mixing process where the mixing zones concentrated directly above and below the impeller. In the experimental work, the acid-base reaction visualization method showed that the mixing zones decreased due to the rotation speed reduction depend on the red and yellow colors, which describe the good mixing and poor mixing zones respectively. The mixing zones were concentrated directly above and below the impeller due to the impeller diameter increasing,. The particles distribution method showed that the mixing zones decreased due to the speed reduction, while the mixing zones concentrated directly above and below the impeller due to the impeller diameter increasing. The results showed a good agreement between the theoretical and experimental works in studying the effect of rotating speed, and impeller diameter

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Numerical Simulation of Production of Microspheres from Polymer Emulsion in Microfluidic Device towards using in Drug Delivery Systems

   أظهر إنتاج الكرات المجهرية من مستحلبات البوليمر باستخدام أجهزة الجريان المايكروية إمكانات كبيرة لتطبيقات توصيل الأدوية نظرًا لقدرتها على تغليف الأدوية وإطلاقها بطريقة خاضعة للرقابة. في هذه الدراسة، تم فحص تأثيرات السرعة والكثافة واللزوجة والتوتر السطحي، وكذلك قطر القناة، على توليد الكراة المجهرية باستخدام برنامج ANSYS. تمت برمجة البرنامج بالخصائص الفيزيائية لمستحلب البوليمر مثل الكثافة واللزوجة والتوتر السطحي. لإجراء المحاكاة والتنبؤ بتدفق السوائل وإنتاج الغلاف المجهري وتحسين تصميم تطبيقات توصيل الأدوية بناءً على التغييرات المذكورة كما تمت دراسة تأثيرات أرقام capillary وWeber.       أظهرت نتائج الدراسة أنه يمكن التحكم في حجم الكرات المجهرية عن طريق ضبط سرعة وقطر القناة. فقد ا نتجت الكرات المجهرية الضيقة عن عرض قناة أضيق ومعدلات تدفق أعلى ، مما قد يحسن كفاءة توصيل الدواء ، بينما انتجت الكرات المجهرية الأصغر عند انخفاض التوتر السطحي البيني. أثرت لزوجة وكثافة مستحلب البوليمر بشكل كبير على حجم الكرات المجهرية، حيث ان زيادة اللزوجة والكثافة تنتج كرات مجهرية أصغر.      كما تم التنبؤ بخصائص التحميل وإطلاق الدواء للكرات المجهرية التي تم إنشاؤها باستخدام تقنية ميكروفلويديك. أظهرت النتائج أن الكرات المجهرية يمكنها تغليف الأدوية بكفاءة وإطلاقها بطريقة خاضعة للرقابة على مدى فترة من الزمن. ويرجع ذلك إلى ارتفاع مساحة السطح إلى نسبة الحجم للكرات المجهرية، مما يسمح بنشر الدواء بكفاءة. وقد توفر القدرة على ضبط عملية التصنيع باستخدام عوامل مثل السرعة والكثافة واللزوجة وقطر القناة والتوتر السطحي فرصة محتملة لتصميم أنظمة توصيل الأدوية بكفاءة أكبر وتأثيرات جانبية أقل.aThe production of microspheres from polymer emulsions using microfluidic devices has shown great potential for drug delivery applications due to their ability to encapsulate and release drugs in a controlled manner. In this study, the effects of velocity, density, viscosity, and surface tension, as well as channel diameter, on microsphere generation were investigated using Fluent Ansys software. The software was programmed with the physical properties of the polymer emulsion such as density, viscosity and surface tension. Simulation will then be performed to predict fluid flow and microsphere production and improve the design of drug delivery applications based on changes in these parameters. The effects of capillary and Weber numbers are also studied.    The results of the study showed that the size of the microspheres can be controlled by adjusting the speed and diameter of the channel. Narrower microspheres resulted from narrower channel widths and higher flow rates, which could improve drug delivery efficiency, while smaller microspheres resulted from lower interfacial surface tension. The viscosity and density of the polymer emulsion significantly affected the size of the microspheres, it`s higher viscosities and densities producing smaller microspheres.    The loading and drug release properties of the microspheres created with the microfluidic technique were also predicted. The results showed that the microspheres can efficiently encapsulate drugs and release them in a controlled manner over a period of time. This is due to the high surface area to volume ratio of the microspheres, which allows for efficient drug diffusion. The ability to tune the manufacturing process using factors such as speed, density, viscosity, channel diameter, and surface tension offers a potential opportunity to design drug delivery systems with greater efficiency and fewer side effects

Numerical approach for enhanced oil recovery with polymer flooding using CMG-STARS program

The polymer recovery efficiency of cationic polyacrylamide (PAM) has been evaluated for use as polymer flooding in the Basra oil reservoir Initially, rheological, physical and petro physical were studied. Additionally, the polymer flooding core flooding experiment has been tested to see how well PAM solutions can be recovered. The comparative study between experimental and numerical study for  PAM solution  has been accomplished in terms of rheological properties , relative permeability curve and oil production. The results showed that PAM solution exhibit shear thinning effect which  can efficiently improve the macroscopic sweep efficiency as well as microscopic displacement efficiency, and viscosity increase with high concentration. The overall recovery efficiency of 94.61 % from sandstone  was determined for 2500ppm PAM flooding. By contrast, brine water flooding was found to be 47.76%, showing that it was less effective than PAM solution. Cost analysis is another factor that affects a project's success. To support the experimental results, a simulation by the Computer Modelling Group (CMG) study has also been conducted

Flow rate effect on partially modified potato starch microspheres formation process

Natural biopolymers are the most likely choice for biomedical applications, and starches can be considered the best materials for such applications. This comes from the fact of their natural origin and their high biodegradable behavior. Native starches have weak hydrogen bonding and a leaching behavior – making it a candidate for drug delivery application. Still, to make starch useful as a drug delivery carrier, this hydrogen bonding must be strengthened. In this work, native sweet potato starch was used, and the hydrogen bonding between starch molecules was enhanced by introducing glycerol as a hydrogen bonding source and sodium alginate (SA) as a thickener. This blend was tested by means of FTIR and DSC, and based on the test results, improved hydrogen bonding had taken place. Furthermore, potato starch microspheres were successfully produced at different flow rates. In the work, a microfluidic capillary device was harnessed to form microsphere generating total flow rates ranging between (0.00031 and 0.00054) cm3/sec. Herein, a starch/sodium alginate/glycerol mixture was used as a dispersed phase and PVA+tween 80 was used as continuous phase. At high flow rates (0.00062-0.00054) cm3/sec, the microspheres took an oval shape. At flow rates (0.00034-0.00048) cm3/sec, the microspheres took a spherical shape. At very low flow rate (0.00031) cm3/sec, the microspheres shell was weak and caused core oozing. In this work, starch microspheres were successfully formed with diameter ranging from (151-263) µm

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population