۱A New Approach to Solve Population Balance Equations in Chemical Processes
نویسنده(ها): ، ،
اطلاعات انتشار: پنجمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۸
Nowadays, population balance is used as a powerful engineering tool in design issues. Different processes in chemical, petrochemical, biotechnology, pharmaceutical industry, etc. deal with particles. In such processes particle or bubble size distribution (PSD) influences the final product quality and also process design. On the other hand solution to the dominant hydrodynamic and thermo–kinetic equations ignoring this distribution will make it impossible to accurately simulate these processes. Solution to population balance equations (PBE’s) is needed to attain the PSD. Since 1940’s many researchers have proposed different methods for easier and also more accurate solution of PBE’s. One of the most common and famous of these methods is the classes method (CM). However, as this method requires a large number of classes to give a reasonable result, it needs a huge amount of calculations and time. To overcome this problem, in this paper a new variant of CM is proposed in which particles in different classes are transformed to new classes in two steps. In the first step, the particles are agglomerated and broken up to form three parallel types of groups, namely: groups formed from agglomerated particles; groups formed from broken up particles and finally a group formed from non–altered particles. In the second step, these parallel groups are combined to redefine classes for next time step. Finally, results of this method, which could be called Parallel Groups Classes Method (PGCM), for different coalescence and breakage kernels are compared with those obtained using analytical solution and CM. Excellent agreement of results of PGCM with analytical solution reveals its effectiveness and accuracy; which will give it an advantage over CM.<\div>

۲Formulating a Break Even Model for Evaluating the Cost of Container Vessels Waiting Times
نویسنده(ها): ، ،
اطلاعات انتشار: دهمین همایش ملی صنایع دریایی ایران، سال
تعداد صفحات: ۲۵
The planning , design and development of a container terminal with optimum size and capacity and with a minimum capital cost is fundamentally dependent upon the loading and discharging operations at the quayside . The quayside function of container terminals is dependent basically on the number of berths available to service the incoming container ships. The objective of the container terminal dealing and admitting the ongoing ship calls is to provide immediate berth and loading and discharging services to the container ships with a minimum costly waiting time and a maximum efficiency. Previously terminal planners used to build extra berths to provide service. During the last two decades the terminal operators have adopted automation technologies in loading and discharging operation of the container ships as an alternative to designing extra berths .ships owners naturally expect least waiting times for their container ships. On the other hand it is also natural for port operators in a container terminal with costly facilities to see a high berth occupancy and productivity at the quayside .<\div>

۳Numerical Modeling of Dam–Break Flows by Weighted Average Flux Method
نویسنده(ها):
اطلاعات انتشار: اولین کنفرانس بین المللی و سومین کنفرانس ملی سد و نیروگاههای برق آبی، سال
تعداد صفحات: ۸
A two–dimensional flow model based on shallow water equations is developed for modeling dam–break flows. The spatial discretisation is obtained by the finite volume cell centered type method, and then the numerical system is solved explicitly. The flux modeling has been deployed by TVD WAF scheme with a second order accuracy both in time and space. The local Riemann problem is solved by the HLLC method in the interface of the cells. The numerical model is verified by comparison of model result and analytical solution. Then the results of numerical model are compared with available experimental data of dam–break in a straight channel over a triangular bottom sill. The results confirm a reasonable performance for the developed model<\div>

۴کاربرد تکنولوژی در عبور حیات وحش از جاده
اطلاعات انتشار: دومین کنفرانس برنامه ریزی و مدیریت محیط زیست، سال
تعداد صفحات: ۵
تصادفات مربوط به حیات وحش و وسایل نقلیه به یک نگرانی عمده برای ایجاد امنیت تبدیل شده است. برای رفع محدودیت های روش سنتی اقدام به یافتن پیشرفت های رو به رشد جهت کاهش این خطرات گردیده که از فناوری جدید تحت عنوان سنسورهای ردیابی Break–The–Beam استفاده می شود، حیوانات وحشی که به غذای کنار جاده جذب می شوند اغلب با وسایل نقلیه برخورد کرده و خطر جدی بقای آنها را تهدید می کند وحتی می تواند منجر به کاهش تعداد آنها و در نهایت تاثیرات بالقوه ای برای زندگی آنها به عنوان جمعیت پایدار گردد. در این سیستم از سنسورهای حساسی برای کاهش حوادث استفاده می شود تا حیوانات بزرگ جثه را با عنوان اینکه آنها به جاده نزدیک می شوند شناسایی کند. این فناوری شامل مناطق تحت پوشش سنسور و سیستم تجزیه کننده پرتوهای انعکاسی می باشد که به دوصورت فعال و غیر فعال وجود دارد سیستم فعال، شامل رادارهای میکروویو می باشد که سیگنال ها را در سرتاسر منطقه تحت پوشش ارسال و انعکاس، بازتاب آن را اندازه گیری می کنند. سیستم غیرفعال شامل ردیاب تصویری و مادون قرمز است که فقط با دریافت سیگنال کار می کند و دارای تجهیزاتی برای تشخیص حرکت جبهه هوای گرم، گرمای موتور وسایل نقلیه و حرکت حیوانات می باشد.
نمایش نتایج ۱ تا ۴ از میان ۴ نتیجه