Flow of gases in exhaust tubes: physical conditions, factors (gases, heat, sound) When exhaust gases leave the combustion chamber their temperature is around 900°C and they travel at speeds lower than the speed of sound. Therefore due to the explosions in the combustion chamber they give off heat, and they give off sound due to pressure variations (compression and decompression of air).
Why do internal combustion engines, either 4-stroke or 2-stroke, even need exhaust systems?
Internal combustion engines need exhaust systems mainly for the following reasons:
to improve power and torque delivery characteristics
to lead hot combusted exhaust gases away
to muffle the sound, i.e. reduce noise emissions (where the intended use of the engine has to be taken into consideration)
Any fool can write code that a computer can understand. Good programmers write code that humans can understand.
Martin Fowler
Saturday, September 10, 2005
Using Tag Library in JSP (for JBoss 4.0 Application Server)
1. in the first line of the JSP file add <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> (or any required tag library) 2. in the deployment descriptor (web.xml), you need to add the following in the <web-app> tag ... xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee web-app_2_4.xsd" version="2.4" ...
List TABLEs, SEQUENCEs or INDEXes in Oracle:
-- list TABLEs SELECT object_name FROM user_objects WHERE object_type = 'TABLE';
-- list SEQUENCEs SELECT object_name FROM user_objects WHERE object_type = 'SEQUENCE';
-- list INDEXes SELECT object_name FROM user_objects WHERE object_type = 'INDEX';
Create user in Oracle:
-- create the user with username//password CREATE USER username IDENTIFIED BY password;
-- grant appropriate role to the user GRANT CONNECT TO username; GRANT RESOURCE TO username;
There's something about going riding with your friends - a feeling of freedom, a feeling of joy - that really can't be put into words. It can only be fully shared by someone who's done it.