## Changes of specific weight

Unlike density, specific weight is not absolute. It depends upon the value of the gravitational acceleration, which varies with location. A significant influence upon the value of specific gravity is the temperature of the material. Pressure may also affect values, depending upon the bulk modulus of the material, but generally, at moderate pressures, has a less significant effect than the other factors. [2]

##  Uses

###  Fluid mechanics

In fluid mechanics, specific weight represents the force exerted by gravity on a unit volume of a fluid. For this reason, units are expressed as force per unit volume (e.g., lb/ft3 or N/m3). Specific weight can be used as a characteristic property of a fluid. [2]

###  Soil mechanics

Specific weight is used as a property of soil often used to solve earthwork problems.

In soil mechanics, specific weight may refer to:

• Moist unit weight, which is the unit weight of a soil when void spaces of the soil contain both water and air.
$gamma = frac{(1+w)G_sgamma_w}{1+e}$

where

$gamma$ is the moist unit weight of the material
$gamma_w$ is the unit weight of water
w is the moisture content of the material
Gs is the specific gravity of the solid
e is the void ratio
• Dry unit weight, which is the unit weight of a soil when all void spaces of the soil are completely filled with air, with no water.

The formula for dry unit weight is:

$gamma_d = frac{G_sgamma_w}{1+e} = frac{gamma}{1+w}$

where

$gamma$ is the moist unit weight of the material
$gamma_d$ is the dry unit weight of the material
$gamma_w$ is the unit weight of water
w is the moisture content of the material
Gs is the specific gravity of the solid
e is the void ratio
• Saturated unit weight, which is the unit weight of a soil when all void spaces of the soil are completely filled with water, with no air.

The formula for saturated unit weight is:

$gamma_s = frac{(G_s+e)gamma_w}{1+e}$

where

$gamma_s$ is the saturated unit weight of the material
$gamma_w$ is the unit weight of water
w is the moisture content of the material
Gs is the specific gravity of the solid
e is the void ratio[3]

###  Mechanical engineering

Specific weight can be used in mechanical engineering to determine the weight of a structure designed to carry certain loads while remaining intact and remaining within limits regarding deformation.

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### Civil Eng. Students

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For CE 370 students : Your second midterm exam will be on Wednesday 27 March 2019. In the surveying lab

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### Mining Engineering

Mining engineering is an engineering discipline that involves practice, theory, science, technology, and the application of extracting and processing minerals from a naturally occurring environment. Mining engineering also includes processing minerals for additional value.

### Environmental Engineering

Environmental engineers are the technical professionals who identify and design solutions for    environmental problems. Environmental engineers provide safe drinking water, treat and properly dispose of wastes, maintain air quality, control water pollution, and remediate sites contaminated due to spills or improper disposal of hazardous substances. They monitor the quality of the air, water, and land. And, they develop new and improved means to protect the environment.

### Proverb

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### Univeristies

Universities I've worked in

Assuit University (Home University), Egypt

Imperial College, London, UK

King Saud University, KSA

,Majmaah University

## My Academic Pages

https://www.researchgate.net/profile/Sameh_Ahemd

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### Course 2018/19-2

1. Surveying 1 CE 370
2. Surveying II  CE 371
3. Senior Design II  (round 6) CE 499

### Latest

Member of the Editorial Board: " Journal of Water Resources and Ocean Sciences"  2013 till now

Participating in The Third International Conference on Water, Energy and Environment,(ICWEE) 2019 - American University of Sharjah, UAE 26-28 March 2019 with a Paper and Poster

New article

### Coming soon

2nd Midterm Exams on 3/4/2019

### Student Conference

Participation  in the 6Th Student Conference

With a paper and oral presentation

From the Senior Design Project CE499 -35

See inside, the paper, and presentation

## 2018-2019S

 Power point Sheets Lecture notes 15 3-4-2019 :Second Midterm Exam Results Model Answer

Working  marks is available -Click on Surveying I

## 2018-2019-2

 Lectures First midterm exam Lab Results

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Working marks out of 60 is  available- Click on Surveying 2

## Photogrammetry

### 2018-2019-1

 Available 0-1-2-3-4 Power point Available Quizzes 2 and 3 with model Answer Quizzes Available Chapter 1,2,3,4,5 Lecture notes Report 1  Cameras Report Y 60 marks Exams

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Student Performance Records

### CE 499 Course

Second Best paper from Senior Design Projects in 2015

Paper title:

### Evaluation of Groundwater Quality Parameters using Multivariate Statistics- a case Study of Majmaah, KSA

Students:

Abdullah A. Alzeer

Husam K. Almubark

Maijd M. Almotairi

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