Thermocapillary Effects in Systems with Variable Liquid Mass Exposed to Concentrated Heating

Abstract: Interface deformation and thermocapillary rupture in a cavity with free upper surface subject to concentrated heating from above is investigated. The dynamics of the process is modulated by placing different amounts of liquid in the cavity. The results determined for large Biot and zero Marangoni numbers show the existence of limit points beyond which steady, continuous interface cannot exist and processes leading to the interface rupture develop. Evolution of the limit point as a function of the mass of the liquid is investigated. The topology of the flow field is found to be qualitatively similar, regardless of whether the cavity is over-filled or only partially filled. The available results demonstrate that cavity over-filling is an effective strategy for prevention of interface rupture, but only when the flow Reynolds number is small. This strategy becomes completely ineffective for high enough Re and deep enough liquid. Cavity over-filling can thus be used as a tool for prevention of rupture, but only under restrictive range of parameters

Biological reactions to different dental implant surface treatments

The treatment of dental implants that increases surface area and roughness enhances bone-to-implant contact ratio; thus, facilitates the immediate loading of dental implants and fastens the osseointegration process. Structural and functional union of the implant with living bone is strongly influenced by the surface properties of the titanium (Ti) implants. As Ti and its alloys cannot directly bond with living bone, modification of implant surface has been introduced to enhance osseointegration. The biological effect of different methods of surface treatment has been studied in vivo and in vitro experiments. This review outlines the biological aspects and the use of certain surface modifications to control bone-to-implant biological response. In this review, we tried to cover a large number of reported studies related to implant surface treatments. Many of these treatments have been tried in the clinic and showed satisfactory results; therefore, specific recommendation regarding the best biocompatible implant surface treatment was hard to conclud

Drinking water quality evaluation of hand pumping wells using water quality index and standard algal toxicity testing in Mansoura and Talkha cities, Egypt

تم اختيار ستة مضخات منزلية حبشية موزعة على قرى مختلفة من مدينتي المنصورة (Mans-I, Mans-II, Mans-III) وطلخا (Talk-I, Talk-II, Talk-III)،مصر ، لتقييم جودة المياه خلال عام 2017. تم جمع عينات المياه خلال منتصف الفصول الأربعة وهي الشتاء والربيع والصيف والخريف. تم استخدام أدوات التقييم القياسية لتقييم جودة المياه اشتملت علىدالة جودة المياه (WQI) ، واختبار الطحالب القياسي للسمية.أوضحت نتائجWQI اختلافات موقعية وموسمية ملحوظة مع جودة مياه  ممتازه (WQI =90) وجيدة (WQI, 70 -89) مسجلة فقط لعينات المياه التي تم جمعها من مضخة Mans-I الموجودة في منطقة قليلة السكان وعلى بعد 50 مترًا فقط من الفرع الشرقي (دمياط) من نهر النيل. أظهرت قيمWQI للمضخات الأخرى الموجودة في المناطق المكتظة بالسكان وعلى بعد كيلومترات من فرع النيل جودة  مياه متوسطة (WQI, 50-69) أو سيئة (WQI, 25-49) حسب موسم أخذ العينات والموقع. جميع عينات المياه التي تم جمعها من مضخة Mans-I كانت غير سامة دون أي آثار مثبطة على نمو طحلب الاختبار القياسيPseudokirchneriella subcapitata. أظهرت عينات المياه المحمعة من جميع المضخات الأخرى تأثيرات سامة واضحة على نمو طحالب الاختبار مع قيم السمية(EC50) متفاوتة تتراوح بين15.8 %و 83 %.. الخلاصة ، كانت جميع عينات المياه التي تم جمعها من مضخة Mans-I آمنة للصحة بينماالعينات التي تم جمعها من مضخات أخرى يمكن أن تشكل مخاطر كبيرة على صحة الإنسان إذا استخدمت للشرب.Six house-hold Abyssinian pumps distributed in different villages of Mansoura (Mans-I, Mans-II and Mans-III) and Talkha (Talk-I, Talk-II and Talk-III) cities, Egypt, have been selected for regular seasonal water quality assessment during 2017. Water samples have been collected within the mid-periods of four seasons Standard assessment tools were employed for the integrated water quality assessment including Water Quality Index (WQI) and ISO standard algal toxicity test. WQI displayed remarkable local and seasonal variations with excellent (≥ 90) and good (70 - 89) only recorded for water samples collected from Mans-I pump located in sparsely populated area and far 50 meters only from the eastern (Damietta) branch of Nile River. WQI of other pumps located in densely populated areas and far kilometers from the Nile branch indicated either medium (50-69) or bad (25-49) quality depending on sampling season and sampling site location. All water samples collected from the pump Mans-I were non toxic without any inhibitory effects on the growth of the standard test alga Pseudokirchneriella subcapitata. Water samples from all other pumps, however, showed obvious toxic effects on test algae growth with varying EC50 values ranged between15.8% and 83%, depending on water sample and the sampling season. Concisely, all water samples collected from Mans-I pump were health safe with acceptable drinking water guidelines while samples collected from other pumps can impose great human health risks if used for drinkin