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Register a new userStudying the flow behavior of white Vaseline "which is used in pharmaceutical industry and Cosmetics" in statical state
دراسة سلوكية الفازلين الأبيض المستخدم في الصناعات الصيدلانية و مستحضرات التجميل في الحالة الراكدة
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هدف هذا البحث إلى دراسة سلوكية الفـازلين الأبـيض المـستخدم فـي الـصناعات الـصيدلانية و مستحضرات التجميل في الحالة الراكدة. أجريت الدراسة على الفازلين الأبيض في الحالة المنصهرة تحت تأثير درجات الحرارة و إجهاد القص و معدل سرعة القص، و ذلك باستخدام مقياس اللزوجـة ذي القالـب الـشعري، و أجريـت التـصحيحات c تنخفض مع الضرورية للمعطيات التجريبية. و من خلال المعطيات التجريبية وجد أن اللزوجة الحقيقية η كما تبين أن المادة المدروسـة مـن فـصيلة المـواد الـشبيهة c . ازدياد معدل سرعة القص الحقيقية γ بالبلاستيك إذ إن 1<n و قد درست تحولات اللزوجة الحقيقية بدلالة مقلوب درجة الحرارة لتعيين طاقة تنشيط الجريان عنـد إجهاد قص ثابت و معدل سرعة قص ثابتة. و من خلال المعطيات تبين أن طاقة تنشيط الجريـان تـنخفض بارتفاع كل من إجهاد القص و معدل سرعة القص، حيث تعبر طاقة تنشيط الجريان عن مـدى حـساسية لزوجة الفازلين تجاه تغير درجة الحرارة. و قد درست مرونة المادة المدروسة باستخدام تقانة باروس (Barus) ، و تبين أن معدل الانتفـاخ B يزداد بارتفاع إجهاد القص و ينخفض بارتفاع مقدار R/L و ليس لدرجات الحرارة تأثير ملحوظ في معامل الانتفاخ B . و تم تعيين زمن مكوث الفازلين في القالب في أثناء الجريان و تحديد العلاقة بين معدل الانتفاخ و زمن المكوث. علماً بأن الفازلين المدروس لا يحمل جراثيم بصفته وسطاً غير مناسب لنموها.
The aim of this work is to study the flow behavior of white Vaseline "which is used in pharmaceutical industry and Cosmetics" in statical state. The study was carried out on the white vaseline in the molten state under the effect of temperture, shear stress (τ), and shear rate (γ) by using capillary viscometer, then the corrections have been done to expermintal data. It was found from the obtained results that, real viscosity decreased with increasing real shear rate (γc). Also it was found that the vaseline is a pseudoplastic material (n<1). For determining viscous activation energy at constant shear rtae (Eγ) and shear stress (Eτ), the relationship between real viscosity (ηc) and (1/T) was studied. It was found that the viscous activation energy decreased with increasing the shear rate and shear stress, where the value of viscous activation energy reflectes the temperature–sensitivity of real viscosity. Elastic properties for vaseline were studied by determining the die swell ratio (B) (Barus effet), and it was found that (B) increased with increasing shear stress, but it decreased with increasing L/R ratio, while the temperature do not have any effect on (B). The time residence (tr) of vaseline in the die was deterimined and studied the relationship between (B) and (tr). Note: vaseline does not carry any kind of bacteria, because it is unsuitable medium for their growth.
References used
Bagley, E. B., 1957. End corrections in the capillary Flow. of Polyethylene, J. Appl. Phys.,V. 28, p. 624
Bagley, E. B., 1961. Energy of Activation For viscous Flow. Trans. Soc. Rheol.,V. 5, p. 355
Charles Panati., 1998. Universalgeschichte der ganz gewöhnlichen Dinge, München S. 282
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