Soft Starters vs. DOL Starters

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Dear Sirs,

I have a 120 KW AC motor that is being started / run by using DOL Starter.

I want to change the starter by a Soft Starter cum Energy Saver.

Can someone suggest me the following -

1. Advantages of using a soft starter

2.Effect on Life of the mo

Questioning Colonoscopy

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Everybody knows that colonoscopy is the best test to screen for colorectal cancer and that colonoscopies save lives. Everybody may be wrong. Colonoscopy is increasingly viewed as the gold standard for colorectal cancer screening, but its reputation is not based on solid evidence. In reality,  it is not yet known for certain whether colonoscopy can help reduce the number of deaths from colorectal cancer. Screening with fecal occult blood testing (FOBT) and flexible sigmoidoscopy are supported by better evidence, but questions remain.  It seems our zeal for screening tests has outstripped the evidence. 

Statistics show that the life-time risk for an adult American to develop colorectal cancer (CRC) is approximately 6%. Colorectal cancer is the second leading cause of cancer deaths in the United States. In the US there are currently 146,970 new cases   and 50,630 deaths each year. Between 1973 and 1995, mortality from CRC declined by 20.5%, and incidence declined by 7.4% in the United States.  

The US Preventive Services Task Force (USPSTF) recommends screening for colorectal cancer (CRC) using fecal occult blood testing, sigmoidoscopy, or colonoscopy, in adults, beginning at age 50 years and continuing until age 75 years.  

The American Cancer Society divides the available tests into these two categories and makes these recommendations for frequency of testing:

Tests that find polyps and cancer

  • flexible sigmoidoscopy every 5 years* 
  • colonoscopy every 10 years 
  • double contrast barium enema every 5 years* 
  • CT colonography (virtual colonoscopy) every 5 years*

Tests that mainly find cancer

  • fecal occult blood test (FOBT) every year*,**
  • fecal immunochemical test (FIT) every year*,**
  • stool DNA test (sDNA), interval uncertain*

 Screening by colonoscopy seems to make more sense than other screening methods, because you can actually see the entire inside of the colon. Colon cancer is preceded by polyps and adenomas that progress to cancer. When a polyp is seen, it can be removed during the procedure. In this study, colonoscopic polypectomy resulted in a lower than expected incidence of colorectal cancer. But other studies suggest that the progression to cancer is not a steady process, and that  adenomas may regress.

There is good evidence here and here that any benefit of colonoscopy is restricted to left-sided colon cancers, with no impact on right-sided colon cancer; we don’t understand why. Some possible explanations are discussed here.  

There are pros and cons to each of the different screening tests.  Barium enemas and CT virtual colonoscopy involve significant doses of radiation. Colonoscopy only needs to be done every 10 years, but it involves an uncomfortable bowel prep, requires sedation, can cause serious complications like bowel perforation, and is unacceptable to some patients. FOBT screening is painless and harmless but has a lot of false positives and requires annual testing. Getting patients to come back every year for FOBT is problematic. Compliance and cost must be considered. Colonoscopy is expensive and there are not enough colonoscopists to screen everyone.

 Apart from all those peripheral considerations, what do we know about the bottom line: the ability of each screening method to prevent deaths from colon cancer?  According to the National Cancer Institute,  

  • Studies have shown that FOBT, when performed every 1 to 2 years in people ages 50 to 80, can help reduce the number of deaths due to colorectal cancer by 15 to 33 percent.
  • Studies suggest that regular screening with sigmoidoscopy after age 50 can help reduce the number of deaths from colorectal cancer, perhaps by as much as 50%, but the quality of evidence is not as good as for FOBT.
  • it is not yet known for certain whether colonoscopy can help reduce the number of deaths from colorectal cancer.

No randomized controlled trials have tested whether colonoscopy reduces the incidence of CRC. Support for the role of colonoscopy in CRC prevention derives from indirect evidence and observational studies.

There is an excellent review of all the pertinent studies here.  Even though studies show that screening can reduce disease-specific mortality from colorectal cancer, there is little evidence that it reduces all-cause mortality.  So as far as we know, screening probably won’t prolong your life. It seems like it should: I don’t understand why it doesn’t, and it bothers me. This certainly isn’t the message we’re getting from the media and from the medical profession.

I’m guessing that if the appropriate studies were done and the technique of colonoscopy were optimized, a reduction in colon cancer deaths would be demonstrated. I’m guessing that colonoscopy would detect more cancers and precancerous lesions than FOBT or sigmoidoscopy, but I’m wondering whether the benefits of colonoscopy would outweigh the additional cost and risks compared to other screening methods. And I’m disturbed that a reduction in all-cause mortality has not yet been clearly shown for any screening method. We need more research to help us understand these issues.

Pending better evidence, I support the current USPSTF recommendations. I think patients should be told the pros and cons and choose which screening test they prefer. I have chosen annual FOBT for myself.


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Conduit Selection

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1) what is the size of pvc rigid conduit required to lay 3c X 4 sq.mm armoured copper cable? 2) what is the outer dia of 3c X 4 sq.mm cable? is there any chart available for selection of conduit size and dia of cables? Reply expected urgently please

Home Security System

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hello. my name is pijeng.

my project is about home security system that using MMS. Let me explain about design of this project first.

Firstly, the system will be detect the movement of any intruder going inside the house. So i believe any IR sensor should be suitable fo

Electric Mini-Motor Design

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I am in the designing stage on a new tool. This tool utilizes 6 small AC electric motors. These motors will have a gear attached, (32 teeth, max. 1" Dia.)
Two of these motors will move a plate (approx. weight >10 lbs.) along a RACK for 6 Ft. The motors will be located on opposite sides of t

Thermal States in Materials

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I am trying to get clarity on the distinctions that exist in descriptions of thermal properties of materials.

In the field of composites, particularly vinylester epoxies cured at room temperature, there is a "transition threshold", a temperature at which the properties of the epoxy change a

Carl Sagan’s mix tape | Cosmic Variance

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Great Valentine’s appropriate story on NPR the other day via the always awesome Radio Lab, involving Carl Sagan,
a whirlwind marriage proposal by phone, a 2500 year old Chinese song, and brain waves of new love sent into space on a golden record for future alien civilizations to find.

This is a love story. And, oddly enough, it starts with an interstellar space mission and a golden record. Toward the end of the summer of ‘77, NASA launched two spacecraft as part of the Voyager Interstellar Mission. On board each craft was a golden record that included, among other things, the sound of a kiss, a mother’s first words to her newborn child, music from all over the world, and greetings in 59 different languages…

Sagan’s wife Ann Druyan tells the story.

Orginally broadcast on the “Space” episode of Radio Lab — listen to the whole thing here.


Water Tube Boiler Jerk Load

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We have a 2700 square feet water tube boiler d type running on natural gas and in winters it is run on solid fuel like wood and rice husk 150 psi running pressure. The problem is that we require steam sporadically and the pressure falls when there is jerk load. This only happens 3-4 times a day

Motor KW Increased

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We have 4650 KW ( SIEMENS) Slip ring Induction motor (Ball Mill) taking input of 6.3 KV and have Liquid starter. When the mill run under normal condition it take 4475 to 4525 KW. But from previous two days (approx 42 Hours) its load remain between 5060 to 4615 KW (Feed to the Ball Mill is normal).

Wrinkle Formation

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We are hot forming the spherical dome of R170 & Thk 7.5. Dome is having S.F. 60mm. We have taken blank dia.600mm. The major problem we are facing is heavy wrinkles during forming. We are carrying forming in 4 stages even the problem is occuring.Dome material is alloy steel.

Suggest your

Space Policy: Go Boldly

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Some Thoughts on the NASA Vision, Jeff Volosin

"I mean no disrespect - but - I am tired of listening to Dr. Spudis, Dr. Griffin and all of the other, whiney, Baby Boomer, Cold Warrior, Manifest Destiny driven individuals who are still trying to live out their 1950's childhood dreams - at taxpayer expense.

Like many of you, for the past 25 years, I have played my own minor role in a vibrant NASA. I have watched as NASA has pushed back the limits of robotic exploration of the solar system with ever more complex and capable probes. In addition, I have seen NASA greatly expanded our view of the Earth - helping us better understand how our environment is changing and how human activities and natural processes contribute to that change. In contrast, human spaceflight has, just during my career, driven off a cliff."

Space Politics Is Always Local

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Cancellation at NASA puts Olson to the test

"Former Rep. Nick Lampson, D-Stafford, who had been in line to lead the House panel overseeing NASA before losing his seat to Olson, blames Texas' current predicament squarely on the sweeping congressional redistricting fashioned by then-House Majority Leader Tom DeLay, R-Sugar Land. "Texas has suffered greatly," said Lampson, who lost races in two congressional districts as a result. "Without that redistricting, I would have been chairman of the space subcommittee representing JSC and in direct contact with the president and House leadership. That would have made a difference."

Astronauts on Decatur rockets, editorial, Decatur Daily

"While NASA workers are legitimately concerned, there are signs that Decatur could enjoy some benefits in the midst of the hardship of a scaled-down Marshall. The most obvious is the potential growth of United Launch Alliance in Decatur. After massive effort, ULA's Decatur plant will soon be the sole assembly plant for three of the most reliable rockets in the United States: the Delta II, the Delta IV and, most recently, the Atlas V."

NASA's new direction could lift local space assets, Virginia Pilot

"President Obama's proposed federal budget for fiscal year 2011 delivered both good and bad news for space- and NASA-related organizations in Hampton Roads such as NASA Langley, NASA's Wallops Flight Facility and the Mid-Atlantic Regional Spaceport."

Obama's budget boosts NASA Ames, San Jose Mecury News

"Key areas of expertise at NASA Ames that are a priority in the new NASA budget include international partnerships, information technology, space science, earth science, small satellites and exploration technologies, Braxton said. NASA Ames employs 1,250 civil servants and 1,250 contractors, but Braxton believes that number may soon increase, and the agency's new direction could be a boon to local employment, not just for NASA but for companies partnering with NASA in Silicon Valley."