The function of thickener, metallic soap, is to hold lubricating oil in a semi-liquid state for easier handling.
When there is rise in temperature, oil bleeds out from thickener and functions as a lubricating agent. When temperature drops again, thickener soaks up oil again to become semi-solid once more.
The type of grease chosen for a particular bearing lubrication application must therefore be chosen very carefully. High temperature grease used in low temperature applications may cause bearings to seize due to lack of lubrication because oil does not bleed out. The common types of grease in use for rolling contact bearings are calcium, sodium and lithium greases.
Calcium Soap Greases
These do not dissolve in water. They are recommended for installations exposed to water at temperatures below 60 degree C. They offer good protection against salt water in marine environments.
Sodium Soap Greases
Also called soda greases, they may be utilized over a wide range of temperatures up to 120 degree C. However, if too much water penetrates into bearings, there is a risk that grease will be washed out and lubricating properties become deteriorated.
Lithium Soap Greases
These have excellent resistance to high temperatures. They can also be used over a wider range of temperatures from -50 to 150 degree C. They are not water soluble.
Additives are also added to some greases to improve their properties. Some examples of these additives are anti-rust, anti-oxidants, extreme pressure additives, and stabilizers.
Reason #2: Desktop Security Software Risks
The risks of placing software on desktop are such that I will be breaking this article into two parts.
Fundamentally we think of having software on our desktops as a good thing. I love downloading or installing new packages and seeing what new creative things people do to user interface or what they do to make certain aspects of my life easier or more fun.
But there are problems inherent with software that resides on desktop, especially security software. All developers will know what I mean. First and foremost, desktop software can be reverse engineered. What’s that mean? Have you ever inadvertently double-clicked on a file and had garbage show up or seen something that looks similar to this?
The old hex dump. Programmers will know it well. We actually spend a good deal of time trying to read this stuff. Basically, if there are programs that can (and do) turn instructions like followingIf UserBirthDate < “01/01/1960” then IsReallyOld = “Yes Else IsReallyOld = “No” End Ifinto something like picture above, then reverse is true: people have developed software that can take that gobbeldy-gook in picture above and turn it somewhat into if-statement I wrote out. The reversing software won’t know that I had an item called UserBirthDate, but it will know I was testing for a value of January 1, 1960 and it will be able to say that based on that value I set another item to Yes or No.So now we install our fool-proof anti-virus software on our desktop (or our firewall for that matter). Well, so too can a virus author. And that virus author or hacker will also have gotten a copy of latest reverse-engineering software from his local hacking site. He now goes upon his task of reverse-engineering software and then trying to decipher results. It’s not easy but it can be done. Unfortunately, vendors know this and understand this as an acceptable risk. The problem here is that your security software is at risk. If your vendor codes an error, virus author can and will detect it. For example, if your vendor should exclude a file from scanning, it’s possible virus author will figure out which file (or type of file) that is and bury his code there. If vendor excludes files from scanning or heuristics, it’s possible that virus author will figure out a way to corrupt that file.That being said, there are other risks. As we have said, once software is on desktop it affords virus authors an opportunity to reverse-engineer security software. The knowledge that reverse-engineering provides is invaluable to a virus author when building his next software attack. Third, virus authors can learn where anti-virus vendors put there software and put links to their software (directory folders, registry entries, etc.). This too is invaluable information. In fact, in some ways it teaches people intent on writing malicious software clues as to how to infiltrate computers’ operating system, where registry entries need to be made to force software to be loaded every time a computer is started, etc.
The old hex dump. Programmers will know it well. We actually spend a good deal of time trying to read this stuff. Basically, if there are programs that can (and do) turn instructions like following
If UserBirthDate < “01/01/1960” then IsReallyOld = “Yes Else IsReallyOld = “No” End If
into something like picture above, then reverse is true: people have developed software that can take that gobbeldy-gook in picture above and turn it somewhat into if-statement I wrote out. The reversing software won’t know that I had an item called UserBirthDate, but it will know I was testing for a value of January 1, 1960 and it will be able to say that based on that value I set another item to Yes or No.
So now we install our fool-proof anti-virus software on our desktop (or our firewall for that matter). Well, so too can a virus author. And that virus author or hacker will also have gotten a copy of latest reverse-engineering software from his local hacking site. He now goes upon his task of reverse-engineering software and then trying to decipher results. It’s not easy but it can be done. Unfortunately, vendors know this and understand this as an acceptable risk.
The problem here is that your security software is at risk. If your vendor codes an error, virus author can and will detect it. For example, if your vendor should exclude a file from scanning, it’s possible virus author will figure out which file (or type of file) that is and bury his code there. If vendor excludes files from scanning or heuristics, it’s possible that virus author will figure out a way to corrupt that file.
That being said, there are other risks. As we have said, once software is on desktop it affords virus authors an opportunity to reverse-engineer security software. The knowledge that reverse-engineering provides is invaluable to a virus author when building his next software attack. Third, virus authors can learn where anti-virus vendors put there software and put links to their software (directory folders, registry entries, etc.). This too is invaluable information. In fact, in some ways it teaches people intent on writing malicious software clues as to how to infiltrate computers’ operating system, where registry entries need to be made to force software to be loaded every time a computer is started, etc.