Download all MATLAB editions with their activations 2002-2014


تحميل جميع اصدارات الماتلاب( Matlab)من 2002-2014

Model-Based Design (MBD) is a mathematical and visual method of addressing problems associated with designing complex control,[1][2] signal processing[3] and communication systems. It is used in many motion control, industrial equipment, aerospace, and automotive applications.[4][5] Model-based design is a methodology applied in designing embedded software


Some of the notable advantages Model-based design offers in comparison to the traditional 

Model-based design provides a common design environment, which facilitates general communication, data analysis, and system verification between development groups.
Engineers can locate and correct errors early in system design, when the time and financial impact of system modification are minimized.

Design reuse, for upgrades and for derivative systems with expanded capabilities, is facilitated

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Materials for structural analysis (books, assignments, power point slides)


I've collected recently these materials during two courses of structural analysis. You all now have these materials between your hands for free.

1.     Textbooks and solution manuals

  •    §  Hibbeler structural analysis 8th Ed text Book 
  •    Download from Here

  •    §  Hibbeler structural analysis 8th Ed Solution Manual 
  •      Download from Here

  •    §  Kassimali Structural Analysis 4th US&SI Text Book
  •      Download from Here

  •    §  Kassimali Structural Analysis 4th US&SI Solution Manual
  •    Download from Here

2.     Assignments

·         Assignment Influence Line          Download
·         Assignment Beam-Frame            Download
·         Assignment-Trusses                    Download
·         Assignment Deflections              Download
·         Assignment force method          Download

3.     Power Point presentation
This power point presentation is an introduction for structural analysis, for the beginners you can use it to understand the basics.

Download HERE

Potential Threats to Our Groundwater - Groundwater Contamination


Over 50% of the United States population depends on groundwater for drinking water. Groundwater is also one of our most important sources of water for irrigation. Unfortunately, groundwater is susceptible to pollutants.

Potential Threats to Our Groundwater - Groundwater Contamination

Groundwater contamination occurs when man-made products such as gasoline, oil, road salts and chemicals get into the groundwater and cause it to become unsafe and unfit for human use.

Materials from the land's surface can move through the soil and end up in the groundwater. For example, pesticides and fertilizers can find their way into groundwater supplies over time. Road salt, toxic substances from mining sites, and used motor oil also may seep into groundwater. In addition, it is possible for untreated waste from septic tanks and toxic chemicals from underground storage tanks and leaky landfills to contaminate groundwater.

Dangers Of Contaminated Groundwater

Drinking contaminated groundwater can have serious health effects. Diseases such as hepatitis and dysentery may be caused by contamination from septic tank waste. Poisoning may be caused by toxins that have leached into well water supplies. Wildlife can also be harmed by contaminated groundwater. Other long term effects such as certain types of cancer may also result from exposure to polluted water.

Potential Sources of Groundwater Contamination

·  Storage Tanks
May contain gasoline, oil, chemicals, or other types of liquids and they can either be above or below ground. There are estimated to be over 10 million storage tanks buried in the United States and over time the tanks can corrode, crack and develop leaks. If the contaminants leak out and get into the groundwater, serious contamination can occur.

·  Septic Systems
Onsite wastewater disposal systems used by homes, offices or other buildings that are not connected to a city sewer system. Septic systems are designed to slowly drain away human waste underground at a slow, harmless rate. An improperly designed, located, constructed, or maintained septic system can leak bacteria, viruses, household chemicals, and other contaminants into the groundwater causing serious problems.

·  Uncontrolled Hazardous Waste
In the U.S. today, there are thought to be over 20,000 known abandoned and uncontrolled hazardous waste sites and the numbers grow every year. Hazardous waste sites can lead to groundwater contamination if there are barrels or other containers laying around that are full of hazardous materials. If there is a leak, these contaminants can eventually make their way down through the soil and into the groundwater.

·  Landfills
Landfills are the places that our garbage is taken to be buried. Landfills are supposed to have a protective bottom layer to prevent contaminants from getting into the water. However, if there is no layer or it is cracked, contaminants from the landfill (car battery acid, paint, household cleaners, etc.) can make their way down into the groundwater.

·  Chemicals and Road Salts
The widespread use of chemicals and road salts is another source of potential groundwater contamination. Chemicals include products used on lawns and farm fields to kill weeds and insects and to fertilize plants, and other products used in homes and businesses. When it rains, these chemicals can seep into the ground and eventually into the water. Road salts are used in the wintertime to put melt ice on roads to keep cars from sliding around. When the ice melts, the salt gets washed off the roads and eventually ends up in the water.

·  Atmospheric Contaminants
Since groundwater is part of the hydrologic cycle, contaminants in other parts of the cycle, such as the atmosphere or bodies of surface water, can eventually be transferred into our groundwater supplies.