## Changes of density

In general, density can be changed by changing either the pressure or the temperature. Increasing the pressure always increases the density of a material. Increasing the temperature generally decreases the density, but there are notable exceptions to this generalization. For example, the density of water increases between its melting point at 0 °C and 4 °C; similar behavior is observed in silicon at low temperatures.

The effect of pressure and temperature on the densities of liquids and solids is small. The compressibility for a typical liquid or solid is 10−6 bar−1 (1 bar = 0.1 MPa) and a typicalthermal expansivity is 10−5 K−1. This roughly translates into needing around ten thousand times atmospheric pressure to reduce the volume of a substance by one percent. (Although the pressures needed may be around a thousand times smaller for sandy soil and some clays.) A one percent expansion of volume typically requires a temperature increase on the order of thousands of degrees Celsius.

In contrast, the density of gases is strongly affected by pressure. The density of an ideal gas is

$ho = frac {MP}{RT}, ,$

where M is the molar massP is the pressure, R is the universal gas constant, and T is the absolute temperature. This means that the density of an ideal gas can be doubled by doubling the pressure, or by halving the absolute temperature.

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### Office hours

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Monday:      12-1

Wednesday: 10-11

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### Civil Eng. Students

DON'T miss!

Love your department and be proud of your field of study

As we approaching the second midterm exams..  Get ready and remember our offices are open to answer you . do not hesitate to .contact me if you have difficulties

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

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### Announcements

My Dear Students

Please visit the  announcement box for the relevant course and make sure that you can download and upload easily, otherwise

.contact me  to sort it out

There will be an orientation session in the midell of this term to help you select your track in Civil and Environmental Engineering

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#### Special Issue

Published Online on January 2016

### 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

Actions speak louder than words

### 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

and give me

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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
Inside, please follow

Working  marks is available -Click on Surveying I

## 2018-2019-2

 Lectures First midterm exam Lab Results

See Inside

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

See Inside

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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## الهيئة السعودية للمهندسين

### Riyadh Metro

A job opportunity

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Mobile: 00966598311652

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