Signals and Systems with MATLAB Computing and Simulink Modeling

اختصاصی از زد فایل Signals and Systems with MATLAB Computing and Simulink Modeling دانلود با لینک مستقیم و پر سرعت .

Author: Steven T Karris

year: 2008

page: 687

Format: pdf

Numerical modeling of non-isothermal reduction of a porous wustite pellet with Syngas

اختصاصی از زد فایل Numerical modeling of non-isothermal reduction of a porous wustite pellet with Syngas دانلود با لینک مستقیم و پر سرعت .

Abstract
A non-isothermal transient model has been developed to simulate the reduction process
and thermal behaviors of a porous wustite pellet undergoing chemical reactions with a
mixture of hydrogen, carbon monoxide, water vapor and carbon dioxide which is
commonly named Syngas. The model describes the chemical reaction itself, the mass
balance for each gaseous species and the energy equation within the pellet. For solution of
the governing equations, a Computational Fluid Dynamic (CFD) approach as a fully
implicit formulation of Finite Volume Method has been applied. The model has then been
validated by comparing with experimental data from literature.

Modeling the impacts of integrated small watershed management on soil erosion and sediment delivery: A case study in the Three

اختصاصی از زد فایل Modeling the impacts of integrated small watershed management on soil erosion and sediment delivery: A case study in the Three Gorges Area, China دانلود با لینک مستقیم و پر سرعت .

Modeling the impacts of integrated small watershed management on soil erosion and sediment delivery: A case study in the Three Gorges Area, China

Journal of Hydrology, Volume 438, p. 156-167

Z.H. Shi a,b,⇑, L. Ai b, N.F. Fang b, H.D. Zhu b.

(c) 2012 Elsevier B.V.

SummarySoil erosion poses a serious problem for sustainable agriculture and the environment. Owing to long-term anthropic pressure including overuse and inappropriate development, soil erosion has become a serious issue in the Three Gorges Area (TGA), China. Recently, integrated small watershed management (ISWM) for soil conservation in the TGA was rapidly developed. This study was conducted to investigate the impact of ISWM on soil erosion and sediment delivery in the Wangjiaqiao watershed in the TGA. The WATEM/SEDEM distributed erosion and sediment transport model was used to evaluate the effectiveness of the ISWM project. The model was calibrated against long-term measured suspended sediments at the watershed outlet. Land use and conservation measures were mapped and analyzed for 1995 and 2005, paying particular attention to quantification of changes in soil erosion and sediment delivery due to ISWM. The results showed that a combination of decreased soil loss (from 18.5 t ha^-1 y^-1 in 1995 to 13.2 t ha^-1 y^-1 in 2005) and increased sediment deposition (from 7.7 to 12.4 t ha^-1 y^-1) has led to a strong decrease in sediment yield (from 8.4 to 3.9 t ha^-1 y^-1) and the sediment delivery ratio (from 0.454 to 0.295). The results of scenario analysis showed that soil conservation measures taken in fields effectively reduce on-site soil loss and sediment yield. However, off-site sediment control measures appear to be much less effective at reducing sediment yield. This diachronic comparison of soil erosion and sediment delivery revealed that ISWM is quite effective and efficient; therefore, it is the appropriate method to combat soil erosion in the TGA and similar areas.

چکیده:

فرسایش خاک یک مشکل جدی برای کشاورزی پایدار و محیط زیست است. فشار بیش از حد انسان بر روی این منابع از جمله استفاده بیش از حد و توسعه نامناسب، سبب شده است که فرسایش خاک به یک مشکل جدی در منطقه TGAچین تبدیل شود. به تازگی، مدیریت یکپارچه حوضه‏های کوچک (ISWM) برای حفاظت خاک در TGA به سرعت توسعه یافته است. این مطالعه به منظور بررسی اثرات ISWM بر فرسایش خاک و تحویل رسوب در حوضه Wangjiaqiaoدر منطقه TGA چین انجام شد.

مدل WATEM/SEDEM توزیع فرسایش و انتقال رسوب برای ارزیابی اثربخشی پروژه ISWM بکار برده شد. مدل برای رسوبات معلق اندازه گیری شده در دراز مدت در خروجی حوضه کالیبره شد. کاربری اراضی و اقدامات حفاظتی نقشه‏برداری شد و برای سال‏های 1995 و 2005 مورد تجزیه و تحلیل قرار گرفت تا تغییرات کمی و کیفی نرخ تحویل رسوب و فرسایش خاک

SOFTWARE FOR MEDICAL IMAGE BASED PHANTOM MODELING

اختصاصی از زد فایل SOFTWARE FOR MEDICAL IMAGE BASED PHANTOM MODELING دانلود با لینک مستقیم و پر سرعت .

Latest treatment planning systems depends strongly on CT images, so the tendency is that the
dosimetry procedures in nuclear medicine therapy be also based on images, such as magnetic
resonance imaging (MRI) or computed tomography (CT), to extract anatomical and histological
information, as well as, functional imaging or activities map as PET or SPECT. This information
associated with the simulation of radiation transport software is used to estimate internal dose in
patients undergoing treatment in nuclear medicine.

This work aims to re-engineer the software SCMS, which is an interface software between the
Monte Carlo code MCNP, and the medical images, that carry information from the patient in
treatment. In other words, the necessary information contained in the images are interpreted and
presented in a specific format to the Monte Carlo MCNP code to perform the simulation of
radiation transport. Therefore, the user does not need to understand complex process of inputting
data on MCNP, as the SCMS is responsible for automatically constructing anatomical data from
the patient, as well as the radioactive source data. The SCMS was originally developed in Fortran-
77. In this work it was rewritten in an object-oriented language (JAVA). New features and data
options have also been incorporated into the software. Thus, the new software has a number of
improvements, such as intuitive GUI and a menu for the selection of the energy spectra
correspondent to a specific radioisotope stored in a XML data bank. The new version also supports
new materials and the user can specify an image region of interest for the calculation of absorbed
dose.