Oil or Grease Lubrication?

Written by Thomas Yoon

A lubricating grease is usually a mixture of 85 to 90 percent mineral oil or synthetic oil together with a thickener. In a majority of all greases,repparttar thickener is a metallic soap. One example is lithium stearate for lithium soap.

The function ofrepparttar 133405 thickener,repparttar 133406 metallic soap, is to hold repparttar 133407 lubricating oil in a semi-liquid state for easier handling.

When there is rise in temperature,repparttar 133408 oil bleeds out fromrepparttar 133409 thickener and functions as a lubricating agent. Whenrepparttar 133410 temperature drops again,repparttar 133411 thickener soaks uprepparttar 133412 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 causerepparttar 133413 bearings to seize due to lack of lubrication because repparttar 133414 oil does not bleed out. The common types of grease in use for rolling contact bearings arerepparttar 133415 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 intorepparttar 133416 bearings, there is a risk thatrepparttar 133417 grease will be washed out andrepparttar 133418 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.

The Risks of Desktop Security Software - Part 1

Written by Tim Klemmer

This isrepparttar second in a series of articles highlighting reasons why we need a new model for anti-virus and security solutions.

Reason #2:repparttar 133404 Desktop Security Software Risks

The risks of placing software onrepparttar 133405 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 torepparttar 133406 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 onrepparttar 133407 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 likerepparttar 133408 following

If UserBirthDate < “01/01/1960” then IsReallyOld = “Yes Else IsReallyOld = “No” End If

into something likerepparttar 133409 picture above, thenrepparttar 133410 reverse is true: people have developed software that can take that gobbeldy-gook inrepparttar 133411 picture above and turn it somewhat intorepparttar 133412 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 ofrepparttar 133413 latest reverse-engineering software from his local hacking site. He now goes upon his task of reverse-engineeringrepparttar 133414 software and then trying to decipherrepparttar 133415 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,repparttar 133416 virus author can and will detect it. For example, if your vendor should exclude a file from scanning, it’s possiblerepparttar 133417 virus author will figure out which file (or type of file) that is and bury his code there. Ifrepparttar 133418 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 onrepparttar 133419 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 whererepparttar 133420 anti-virus vendors put there software and putrepparttar 133421 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 infiltraterepparttar 133422 computers’ operating system, where registry entries need to be made to force software to be loaded every time a computer is started, etc.

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