J Factor

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Dear Sir,

In 1 1/4 Cr-1/2 Mo material J factor is not required, While in case of 2 1/4 Cr-1Mo material J factor is required to calculate. Can you explain me why J factor is required? What is impact on material with consideration of J factor? Why J Factor is not calculated for 1 1/4Cr-1/2 Mo m

Project Ideas

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I know my question won't suite everyone.

I just want to ask, as being a Freshman what are the different projects that I should do because my branch is Mechanical engineering?

Every answer would be important for me.

Why NASA Keeps a Close Eye on the Sun’s Irradiance

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Sunspots are darker areas of the Sun that have lower solar irradiance than other areasFor more than two centuries, scientists have wondered how much heat and light the sun expels, and whether this energy varies enough to change Earth’s climate. In the absence of a good method for measuring the sun's output, the scientific conversation was often heavy with speculation.

By 1976, that began to change when Jack Eddy, a solar astronomer from Boulder, Colo., examined historical records of sunspots and published a seminal paper that showed some century-long variations in solar activity are connected with major climatic shifts. Eddy helped show that an extended lull in solar activity during the 17th Century --called the Maunder Minimum -- was likely connected to a decades-long cold period on Earth called the "Little Ice Age."

Two years after Eddy published his paper, NASA launched the first in a series of satellite instruments called radiometers, which measure the amount of sunlight striking the top of Earth's atmosphere, or total solar irradiance. Radiometers have provided unparalleled details about how the sun's irradiance has varied in the decades since. Such measurements have helped validate and expand upon Eddy's findings. And they've led to a number of other discoveries—and questions—about the sun.

Without radiometers, scientists would probably still wonder how much energy the sun emits and whether it varies with the sunspot cycle. They wouldn't know of the competition between dark sunspots and bright spots called faculae that drives irradiance variations.

And they’d have little chance of answering a question that continues to perplex solar experts today: Has overall irradiance changed progressively throughout the past three 11-year cycles, or are variations in the sun's irradiance limited to a single cycle?

The answer has important implications for understanding climate change, as some scientists have suggested that trends in solar irradiance account for a significant portion of global warming.

The next space radiometer, slated for launch this November aboard NASA's Glory satellite, should help chip away at the uncertainty that surrounding the sun's role in climate change.

A Variable Sun It's well known today that the sun's irradiance fluctuates constantly in conjunction with sunspots, which become more and less abundant every 11 years due to turbulent magnetic fields that course through the sun's interior and erupt onto its surface.

But as recently as the 1970s, scientists assumed that the sun’s irradiance was unchanging; the amount of energy it expels was even called the "solar constant."

It was data from radiometers aboard Nimbus 7, launched in 1978, and the Solar Maximum Mission, launched two years later, that were the death knell to the solar constant. Soon after launching, instruments aboard both satellites showed that solar irradiance changed significantly as patches of sunspots rotated around the sun's surface. Irradiance would fall, for example, when groups of sunspots faced Earth. And it would recover when the sunspots rotated to the far side of the sun.
Like sunspots, solar prominences are more likely to occur during the most active part of the solar cycle
Likewise, in 2003, a radiometer aboard NASA's Solar Radiation and Climate Experiment (SORCE) satellite observed large sunspot patches that caused irradiance to drop by as much 0.34 percent, the largest short-term decrease ever recorded.

"When you look at longer scales on the sun, it's the opposite," said Lean, a solar scientist at the U.S. Naval Research Laboratory in Washington, D.C., and a member of Glory's science team. "Overall, irradiance actually increases when the sun is more active even though sunspots are more common."

How can increases in dark, cool sunspots yield increases in irradiance? "It didn't make much sense until we were able to show that sunspots are just half of the story," said Lean.

Measurements collected during the 1980s and 1990s gave scientists the evidence they needed to prove that irradiance is actually a balance between darkening from sunspots and brightening from accompanying hot regions called faculae, a word meaning "bright torch" in Latin.

When solar activity increases, as it does every 11 years or so, both sunspots and faculae become more numerous. But during the peak of a cycle, the faculae brighten the sun more than sunspots dim it.

Overall, radiometers show that the sun’s irradiance changes by about 0.1 percent as the number of sunspots varies from about 20 sunspots or less per year during periods of low activity (solar minimum) to between 100 and 150 during periods of high activity (solar maximum).

“That may seem like a tiny amount, but it’s critical we understand even these small changes if we want to understand whether the sun's output is trending up or down and affecting climate,” said Greg Kopp, a principal investigator for Glory and scientist at the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

Though most scientists believe the 0.1 percent variation is too subtle to explain all of the recent warming, it's not impossible that long-term patterns -- proceeding over hundreds or thousands of years -- could cause more severe swings that could have profound impacts on climate.
Although sunspots cause a decrease in irradiance they're accompanied by bright white blotches called faculae that cause an overall increase in solar irradiance
Searching for a Trend Line A total of 10 radiometers have monitored the sun since Nimbus 7, and by patching all of the measurements together into one data stream, scientists have tried to identify whether the sun’s irradiance has increased or decreased over the last three cycles.

However, melding the results from different instruments has proven complicated because many of the radiometers record slightly different absolute measurements. And the areas of overlap between instruments in the long-term record aren't as robust as scientists would like.

As a result, questions remain about how the sun's irradiance has changed. Richard Willson, principal investigator for NASA's Active Cavity Radiometer Irradiance Monitor (ACRIM), reported in a 2003 paper that the overall brightness of the sun was increasing by 0.05 percent per decade.

Subsequent assessments of the same data have come to a different conclusion. Other groups of scientists have shown that the apparent upward trend is actually an artifact of the radiometers and how they degrade in orbit. Complicating the issue further, an instrument aboard NASA's Solar and Heliospheric Observatory (SOHO) measured irradiance levels during a solar minimum in 2008 that were actually lower than the previous solar minimum.

Which measurements are right? Has the sun experienced subtle brightening or dimming during the last few solar cycles? Such questions remain controversial, but the radiometer aboard Glory, called the Total Irradiance Monitor (TIM), is ready to provide answers. The Glory TIM will be more accurate and stable than previous instruments because of unique optical and electrical advances. And each of its components has undergone a rigorous regime of calibrations at a newly-built facility at the University of Colorado.

“It’s a very exciting time to be studying the sun,” said Lean. “Every day there's something new, and we’re on the verge of answering some very important questions.”


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NASA Satellites Keep Watch on Gulf Current Near Spill

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Graph showing the speed and direction of surface currents in the Gulf
NASA satellite altimetry data are being used in combination with data from other satellites to track changes in a huge warm ocean current in the Gulf of Mexico that could transport oil from the Deepwater Horizon oil rig far away from the Gulf. › Full image and caption
Scientists and agencies monitoring the oil spill in the Gulf of Mexico are keeping a wary eye on changes in the nearby Loop Current, a warm ocean current that is part of the Gulf Stream. Beginning as a large flow of warm water from the Caribbean, the Loop Current heads up into the eastern part of the Gulf of Mexico and then turns south before finally moving out through the Straits of Florida and northward into the Gulf Stream. Deep and fast moving, the Loop Current often breaks off and forms strong, clockwise rotating eddies called anticyclones that travel westward into the Gulf. The currents along the outer edges of the Loop Current, as well as these eddies, have been clocked at speeds as high as three to four knots (three to five miles per hour), comparable to the fastest ocean currents ever observed.

Because the Loop Current and its eddies are warmer, and thus higher in surface elevation, than the surrounding waters, they are easily spotted by satellite altimeters, such as those aboard the NASA/French Space Agency Jason 1 and Ocean Surface Topography Mission/Jason 2 satellites. Scientists use the latest satellite measurements of sea-surface height from these and other satellite altimeters to create maps showing the location, direction and speed of currents in the Gulf of Mexico.

This image, created on May 23, 2010, using measurements of sea surface height from multiple satellites, including Jason-1 and OSTM/Jason-2, shows the speed and direction of surface currents in the Gulf. The northern portion of the Loop Current, shown in red, appears about to detach and form a separate eddy--a large, warm, clockwise-spinning vortex of water that is the ocean's version of a cyclone. The star shows the former location of the Deepwater Horizon drilling rig that exploded and sank in April, and has been leaking oil since. Scientists believe a large eddy between the oil spill and the Loop Current could keep, at least temporarily, some of the spilling oil from reaching the Florida Straits and the Gulf Stream.

This map was produced by the Colorado Center for Astrodynamics Research in Boulder, Colo. The center processes satellite measurements of sea surface height in near real-time to create maps of the Gulf of Mexico, showing the location of medium-sized eddies and fronts. More information on these data products is available at http://argo.colorado.edu/~realtime/welcome/.


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The Glory Mission’s Judith Lean Discusses Solar Variability

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Judith LeanThough the sun's brightness was once thought to be constant, NASA has launched a series of satellite instruments that have helped show it actually fluctuates in conjunction with cycles of solar activity.

With a new sun-watching instrument called the Total Irradiance Monitor (TIM) scheduled to launch on NASA's Glory satellite in November, we spoke with Judith Lean, a member of the Glory science team and solar physicist at the United States Naval Research Laboratory, about solar cycles and what scientists have learned about solar variability in the last three decades.

What is a solar cycle and how long does it last?
For more than a century, people have noticed that sunspots become more and less frequent on an 11-year-cycle. That’s the main solar cycle we look at. The 11-year-cycle is really part of a 22-year-cycle of the sun’s magnetic field polarity. The changes are driven by something called the solar dynamo, a process that generates and alters the strength of the magnetic field erupting onto the sun's surface. It's the sun’s magnetic field that produces sunspots as it moves up through the sun's surface.

How much does the brightness of the sun change throughout the cycle?
It's a small amount. Total solar irradiance typically increases by about 0.1 percent during periods of high activity. However, certain wavelengths of sunlight—such as ultraviolet—vary more.

What causes irradiance to change?
It's really the balance of sunspots, which are cooler dark areas of the sun, and faculae, bright areas that appear near sunspots. The faculae overwhelm the sunspots, so the sun is actually brighter when there are more sunspots.

Can changes in the sun affect our climate?
If it wasn’t for the sun, we wouldn’t have a climate. The sun provides the energy to drive our climate, and even small changes in the sun's output can have a direct impact on Earth. There are two ways irradiance changes can alter climate: One is the direct effect from altering the amount of radiation reaching Earth. The second is that solar variability can affect ozone production, which can in turn affect the climate.

Does the 0.1 percent change in irradiance affect Earth's climate much?
Solar irradiance changes are likely connected to dynamic aspects of climate—things like the coupling of the atmosphere and ocean—El Niño being one example—or aspects of atmospheric circulation, such as the Hadley cells that dominate in the tropics.
But we've done a great deal of modeling, and the sun doesn't explain the global warming that's occurred over the last century. We think changes in irradiance account for about 10 percent global warming at most. Of course, there are also longer cycles that may have an impact on climate, but our understanding of them is limited.

There is disagreement about whether the last three cycles have gotten successively brighter. Has that been resolved?
No, it hasn't. The best understanding is that irradiance cycles have been about the same in the last three cycles, but one group reports an increasing trend whereas another group says that current levels are now the lowest of the entire 30-year record. I believe these differences are due to instrumental effects, but we really need continual, highly accurate, and stable long-term measurements to resolve this. The radiometer aboard Glory—the Total Irradiance Monitor (TIM)--will be a big step, quite an exciting advance.

What part of the 11-year cycle will Glory observe?
Glory is going is to observe during the ascending phase of the cycle. The ascending phase is relatively rapid, so we should get to the peak in about three years. Then there will be about two years or more when solar activity is high and stays high. About five years from now, activity will start to come down again so that by, say, 2019 we will be at low levels again.

What do you hope Glory will find?
The Glory TIM has been calibrated more rigorously than previous instruments, so it should help a lot in getting the absolute brightness of the sun. In addition to recording the ever-changing irradiance levels, it should measure irradiance precisely enough that will make it feasible to determine whether solar irradiance is stable or changing, if the measurements continue long enough into the future.

Are there aspects of the solar variability that TIM won't measure?
Yes. The Glory TIM looks at overall irradiance, but it doesn't measure how specific parts of the spectrum—the ultraviolet, visible, or infrared—are changing. Some of the largest changes actually happen at the shortest wavelengths, so it's extremely important that we look at the spectrum. There's an instrument related to TIM called the Solar Irradiance Monitor (SIM) aboard the SORCE satellite that lets us see how individual parts of the spectrum vary, and it's also critical.

The sun has been exceptionally quiet in recent years. Are we entering a prolonged solar minimum?
There was a period from mid-2008 to mid-2009 when the sun was without sunspots for many days. It was probably the quietest period we've seen since the first total solar irradiance measurements. But we didn't go into a prolonged minimum because the sun still had a few active regions – not sunspots, but small bright faculae regions -- and we could see the irradiance continue to fluctuate throughout this very quiet period. Now there are more dark sunspots and more bright faculae on the sun’s surface, so activity is ramping up and a new cycle--solar cycle 24--has started.

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Spacecraft Reveals Small Solar Events Have Large Scale Effects

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image of the SDO satellite orbiting EarthNASA's Solar Dynamics Observatory, or SDO, has allowed scientists for the first time to comprehensively view the dynamic nature of storms on the sun. Solar storms have been recognized as a cause of technological problems on Earth since the invention of the telegraph in the 19th century.

The Atmospheric Imaging Assembly (AIA), one of three instruments aboard SDO, allowed scientists to discover that even minor solar events are never truly small scale. Shortly after AIA opened its doors on March 30, scientists observed a large eruptive prominence on the sun's edge, followed by a filament eruption a third of the way across the star's disk from the eruption.

"Even small events restructure large regions of the solar surface," said Alan Title, AIA principal investigator at Lockheed Martin Advanced Technology Center in Palo Alto, Calif. "It's been possible to recognize the size of these regions because of the combination of spatial, temporal and area coverage provided by AIA."

The AIA instrument also has observed a number of very small flares that have generated magnetic instabilities and waves with clearly-observed effects over a substantial fraction of the solar surface. The instrument is capturing full-disk images in eight different temperature bands that span 10,000 to 36-million degrees Fahrenheit. This allows scientists to observe entire events that are very difficult to discern by looking in a single temperature band, at a slower rate, or over a more limited field of view.

The data from SDO is providing a torrent of new information and spectacular images to be studied and interpreted. Using AIA's high-resolution and nearly continuous full-disk images of the sun, scientists have a better understanding of how even small events on our nearest star can significantly impact technological infrastructure on Earth.

Solar storms produce disturbances in electromagnetic fields that can induce large currents in wires, disrupting power lines and causing widespread blackouts. The storms can interfere with global positioning systems, cable television, and communications between ground controllers and satellites and airplane pilots flying near Earth's poles. Radio noise from solar storms also can disrupt cell phone service.

Launched in Feb. 2010, the spacecraft's commissioning May 14 confirmed all three of its instruments successfully passed an on-orbit checkout, were calibrated and are collecting science data.

"We're already at five million images and counting," said Dean Pesnell, the SDO project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "With data and images pouring in from SDO, solar scientists are poised to make discoveries that will rewrite the books on how changes in solar activity have a direct effect on Earth. The observatory is working great, and it's just going to get better."

Goddard built, operates and manages the SDO spacecraft for NASA's Science Mission Directorate in Washington. SDO is the first mission of NASA's Living with a Star Program. The program's goal is to develop the scientific understanding necessary to address those aspects of the sun-Earth system that directly affect our lives and society.

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Reedbed skulker…

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That no Puffin - the bird on the left - a Water Rail!!


Monday 24th May comments:

The season continues to throw up surprises as the early nesting season was unexpected, the weather has been unpredictable (as ever!) and the islands continue to attract strange and wonderful birds from various parts of the globe. On Saturday it was the turn of a Water Rail to put in an appearance, a bird normally associated with reedbeds and not normally showy - unlike this one! The bird, an adult, was observed happily running down Puffin burrows on Inner Farne to feed on earthworms and the like whilst the watching Shags and Guillemots looked on amused. So the photo above may not be the best, but it captures the moment - birding Farnes style!
On the breeding seabird front, the first Kittiwake eggs have started to hatch, Razorbills are now parents and everything goes on as normal - although on the islands, I'm never sure what is normal! It won't be long before we are undertaking the biggest of all jobs - the annual seabird population counts and fingers crossed for some positive results - but watch out, Eiders crashing out....? We'll have to wait and see.

Craigorio Does Italia

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It was just about family when Craig Cisero made his way to Italy on a six month pilgrimage. Little did he know what would really transpire… From harvesting grapes to teaching English, Craigorio Does Italia tells Craig’s tale of tracing his roots and finding much more along the way. (The story isn’t over yet.)

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Almaty

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We are in Almaty since 2 days. Everything perfect despite the road from Aktoebe down to Aral was in very bad condition and additional there is a lot of construction thus makes it necessary to by pass the old road through tracks in the velds. Heading north now direction Altai.

Bunkin’ with the Barreras

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Anyone who knows me fairly well will probably know that I have a deep love for Latin America. I'm often asked what it is that draws me to this part of the world. While I could say things like cheesey soap operas delicious food rich colors and music en espaol and these are all things that I do in fact love the most correct answer would be the importance of family. As part of my internship

Day 12 New York City

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Hi AllToday we woke up in Philadelphia PA and from our room on the ninth floor we can see the awesome sky line of downtown Philadelphia Independence Hall and the Phillis stadium wow what a view. We went to old town and saw the Liberty Bell and took dozens of pictures. From there it only took an hour and a half to get to New Jersey where we have a hotel for the next two nights. We had to walk

Beautiful Green Idaho

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We left Heyburn on Hwy 30 driving through beautiful farmland through towns with names like Burley Murtaugh the little town with the big heart Twin Forks Buhl trout capitol of the world to Hagerman. At Hagerman we stopped at the Hagerman Fossil Beds National Monument visitor center which as it turns out is closed on Tuesdays and Wednesdays. So we got on I84 and drove to Boise.In Boise

Day 11 Philadelphia

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Hi EverybodyToday we went to Hershey PA and toured the chocolate factory and got a free sample of chocolate which ended up being a mini Hershey bar. We took lots of pictures and as you can see we bought a lot of candy. Did you know that there streets are the color of chocolate and the street light are Hershey Kisses the dirt even looks like chocolate what a place.From Hershey we drove to Phila

WEST COAST OZ

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first stop cervanties the pinnacles at sunrise... free into the national park who could complain passed through the tiniest town in the work called none other than... greenough a bit of home from home never does anyone harm. a bit of free camping lighting fires and using the infamous camp oven i am now addicted to spuds dolphins at monkey mia and the very underrated ocean world. using the

Day 10 Gettysburg

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HiWe started our day by getting really neat pictures out of our 9th floor window. We checked out and went to the Smithsonian National Air and Space Museum. We ate at the largest McDonalds we had ever seen in our lives on one side it had four kitchens and on the other side of the room the same and a McDonaldrsquos dessert station. We spent a couple of hours at the museum had fun took pictures

The long road to Mt Everest

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Ok65292this is the second time I am writing this entry12290 Not sure what happened to the first one but it is gone12290For this entry I will fill you in on the trip from Nepal into China 65288Tibet65289 and the side trip to Mt Everest basecamp12290 I am currently in a town halfway between Mt Everest and Lhasa12290 Sorry I do not have my map handy and do not remember the name

The Eagle Has Landed

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Wednesday 26 MayWell here we are in Athens after a routine flight with BA. Our 767 was completely full. We flew across the northern part of France right across Germany could pick out the Rhine River and then across a broad stretch of the Alps crossing Austria and then the Balkan States. Greece looked very dry from the air but pictureque with its many islands. Athens looked a sea of whit