Hello everyone;
I will be conducting a vibration test shortly, and I need information on how to mount the accelerometers. I'll first tell my testing conditions
Sine test: 5-100Hz; 20g maximum force between 21-60Hz
Random Vibration: 5-2000Hz; trapezoid spectrum with 0,65 g^
Black carbon, a short-lived particle, is in perpetual motion across the globe. The Tibetan Plateau's high levels of black carbon likely impact the region's temperature, clouds and monsoon season.
The needle-in-a-haystack object found by Hubble is only 3,200 feet across and a whopping 4.2 billion miles away. The smallest Kuiper Belt Object (KBO) seen previously in reflected light is roughly 30 miles across, or 50 times larger.
This is the first observational evidence for a population of comet-sized bodies in the Kuiper Belt that are being ground down through collisions. The Kuiper Belt is therefore collisionally evolving, meaning that the region's icy content has been modified over the past 4.5 billion years.
The object detected by Hubble is so faint - at 35th magnitude -- it is 100 times dimmer than what the Hubble can see directly.
So then how did the space telescope uncover such a small body?
In a paper published in the December 17th issue of the journal Nature, Hilke Schlichting of the California Institute of Technology in Pasadena, Calif., and her collaborators are reporting that the telltale signature of the small vagabond was extracted from Hubble's pointing data, not by direct imaging.
Hubble has three optical instruments called Fine Guidance Sensors (FGS). The FGSs provide high-precision navigational information to the space observatory's attitude control systems by looking at select guide stars for pointing. The sensors exploit the wavelike nature of light to make precise measurement of the location of stars.
Schlichting and her co-investigators determined that the FGS instruments are so good that they can see the effects of a small object passing in front of a star. This would cause a brief occultation and diffraction signature in the FGS data as the light from the background guide star was bent around the intervening foreground KBO.
They selected 4.5 years of FGS observations for analysis. Hubble spent a total of 12,000 hours during this period looking along a strip of sky within 20 degrees of the solar system's ecliptic plane, where the majority of KBOs should dwell. The team analyzed the FGS observations of 50,000 guide stars in total.
Scouring the huge database, Schlichting and her team found a single 0.3-second-long occultation event. This was only possible because the FGS instruments sample changes in starlight 40 times a second. The duration of the occultation was short largely because of the Earth's orbital motion around the sun.
They assumed the KBO was in a circular orbit and inclined 14 degrees to the ecliptic. The KBO's distance was estimated from the duration of the occultation, and the amount of dimming was used to calculate the size of the object. "I was very thrilled to find this in the data," says Schlichting.
Hubble observations of nearby stars show that a number of them have Kuiper Belt-like disks of icy debris encircling them. These disks are the remnants of planetary formation. The prediction is that over billions of years the debris should collide, grinding the KBO-type objects down to ever smaller pieces that were not part of the original Kuiper Belt population.
The finding is a powerful illustration of the capability of archived Hubble data to produce important new discoveries. In an effort to uncover additional small KBOs, the team plans to analyze the remaining FGS data for nearly the full duration of Hubble operations since its launch in 1990.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute conducts Hubble science operations. The institute is operated for NASA by the Association of Universities for Research in Astronomy, Inc. in Washington, and is an International Year of Astronomy 2009 program partner.
For illustrations, and more information, visit:
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On Tuesday, Dec. 15, NASA, Alliant Techsystems (ATK) and Lockheed Martin celebrated a major milestone with a ground test of a full-scale attitude control motor (ACM) for the Orion crew exploration vehicle’s launch abort system (LAS).+ View low-angle video
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"The completion of the Demonstration Motor 1 hot-fire test is a substantial advancement in developing the ACM," said LAS Manager Kevin Rivers, of NASA’s Langley Research Center in Hampton, Va. "With an elaborate eight-valve control system that relies on advanced ceramic composites for several key components, the ACM is among the most complex solid rocket systems ever built."
The test performed at ATK’s facility in Elkton, Md., was the sixth in a series of ground tests of Orion’s attitude control motor system. The ACM is charged with keeping the crew module on a controlled flight path after it jettisons, steering it away from the Ares 1 crew launch vehicle in the event of an emergency, and then reorienting the module for parachute deployment.
Having reached this milestone brings Constellation another step closer to flight-ready status and demonstrates progress toward improved flight safety for astronauts, which is at the core of Constellation Program success.
The launch abort system, mounted on top of the Orion crew module, centers around three solid propellant rocket motors: an abort motor, an attitude control motor; and a jettison motor. Successful tests of both the abort and jettison motors were completed in 2008. The attitude control motor consists of a solid propellant gas generator, with eight proportional valves equally spaced around the outside of the 32-inch diameter motor. Together, the valves can exert up to 7,000 pounds of steering force to the vehicle in any direction upon command from the crew module.
"Controllable solid rockets have only recently begun seeing application in spacecraft, and the ACM delivers an order of magnitude greater thrust than any of those systems," said Rivers. "It represents a significant technical advancement in controllable solid propulsion."
Testing wouldn’t be possible without the support and hard work from the ATK, Lockheed Martin and NASA LAS teams.
"There are many dedicated people from across the nation who have worked diligently to overcome technical challenges to make the test happen,” said Rivers. “I am proud of each of them."
The entire launch abort system will be demonstrated during a Pad Abort 1 flight test at the U.S. Army’s White Sands Missile Range (WSMR) in New Mexico in the spring of 2010.
The attitude control motor for the flight test is scheduled to be delivered to WSMR in January, followed by the stacking of the launch abort system.
Langley manages the launch abort system design and development effort with partners and team members from NASA’s Marshall Space Flight Center in Huntsville, Ala. Langley’s Launch Abort System Office performs this function as part of the Orion Project Office located at NASA’s Johnson Space Center in Houston. ATK is under contract with Lockheed Martin, NASA’s prime contractor for Orion, to develop and test the attitude control motor.
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The Arctic remains in the mind a pristine wonderland. The landmasses that jut into the Arctic Circle are covered by tundra and primeval forest; the pole is covered in ice. The whole environment seems detached from human influence entirely. But the scientific record tells a different story.A months-long airborne campaign in 2008 gave scientists a new look at how everyday human behaviors in Europe, North America and Asia are affecting the Arctic, the most rapidly changing region on Earth and a major regulator of the planet's climate. The data show human fingerprints all over the Arctic in the form of polluted exhaust from factories and smoke from fires often set by human hands. Observations from the ground have long recorded some of this impact, and satellites in low-earth orbit provide a different view, but scientists had not undertaken a detailed, airborne study of this magnitude in years.
The mission provided a new view of how pollution from industrializing Asian countries influences the Arctic. Ground sensors have long detected the regular, low-altitude movement of polluted air masses from Europe to the Arctic. Because of the colder temperatures in the countries of the pollution's origin, the plumes of carbon dioxide, carbon monoxide and other warming-related gases do not rise high in the atmosphere. On the contrary, pollution from warmer regions in Asia has apparently been moving to altitudes too high for ground instruments to observe well. The airborne instruments provided invaluable measurements of the extent of this pollution, said Daniel Jacob, a Harvard University atmospheric scientist and both mission scientist and co-principal investigator for NASA’s Arctic Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission.
"With Asian pollution, there's a relatively warm ocean immediately downwind of a fairly cold continent, so you have interesting storm tracks that lift pollution and transport it at higher altitudes," Jacob said. "It's certainly a much larger influence on Arctic haze than what had been traditionally ascribed."
Now that researchers have had some time to sift through the data collected, Jacob said the value of these observations is coming in to focus. Major airborne campaigns like this are rare, so almost any study of the Arctic atmosphere in coming years will draw on ARCTAS.
"We're getting to the point where results from ARCTAS are getting into climate models. We’re able to test different models of snow albedoes, and we've been able to introduce some corrections," Jacob said. "From the standpoint of the Asian pollution influence, if you want to claim Asia has a certain influence, you better check it against the ARCTAS results."
While factories, power plants and cars on the highway provide a 365-day-a-year source of pollution, the Arctic flights revealed insights into a more cyclical source of emissions: fires in boreal forests and from agricultural burning as far away as Kazakhstan. In concert with NASA, NOAA sponsored spring flights as part of a field study called Aerosols, Radiation and Cloud Processes affecting Arctic Climate (ARCPAC). These flights observed an unusually active spring fire season. Even if the data collected was somewhat anomalous, scientists say it has provided great insight into fire and smoke influence on the Arctic. In addition, there is some evidence that as the Arctic warms and dries out, there is more fuel for these fires.
"We expected to see pollution. But it turns out there's a seasonal cycle to fires, and there’s a springtime peak and summertime peak," said Chuck Brock, ARCPAC project scientist. "I don't think we appreciated that these fires in Siberia and in southern Russia could be so dominant and important in the Arctic. So, is 2008 representative or is it an unusual year? But every year there is this peak, and every year this smoke gets carried to the Arctic."
Brock said the wealth of data will be important in studying the link between smoke and cloud formation and the repercussions of this link. For instance, could there be an impact on snowmelt -- through aerosol-related warming -- if the spring fire season inches up by even a week or two?
The campaigns also provided the opportunity to create a sharper picture of several specific emission sources of greenhouse gases that find their way to the Arctic. Scientists focused on emissions from the oil and gas industry in Prudhoe Bay, Alaska and the natural methane emissions from the massive wetlands near Hudson Bay in Canada. These are two examples of the many variables that need to be accurately characterized in order for scientists to understand what is driving Arctic warming.
It is the rarity of these measurements that makes them important to future study of the Arctic climate, said Jim Crawford, a research scientist at NASA's Langley Research Center and the ARCTAS program manager during the campaign. The data gathered will allow scientists to better interpret satellite observations and better simulate how industrial pollution and wildfire smoke affect the Arctic.
"For scientists interested in studying the role of changing atmospheric composition on climate, the ARCTAS data will represent the best and often only detailed information available for this poorly characterized region," Crawford said.
Related Links:
› ARCTAS Mission
› NASA's Earth Science Project Office
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The NASA Audio File page has sound clips with NASA scientists, researchers, astronauts, and officials supporting timely news releases about everything from the latest discoveries in space to climate change here on Earth. The page also will offer sound excerpts suitable for audio news features.
The NASA Audio File page can be accessed at:
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Hai;
I am sure that anyone could help me with this.I need reliable references abt the ASME codes regarding System Design(Conveyor systems) Could anyone help with tha?
Hai Tech Savvys;
I was going through the standards of bearings regarding the design of certain mechanisms (conveyor mechanisms) used in a system design process. My boss asked me to put "operational clearence" for the bearings which are mounted on a shaft.I got confused.I couldn't find a thi
hello all,
anybody know about the dc ct?
application or tch details or upcoming ??any..
is it appilded for Traction system??
MULTIMEDIA ART FESTIVAL
Mémoire et Futurisme – Memory and Futurism
December 6-13, 2009
Alexandria
December 13-18, 2009
Cairo
*Workshops, video art, conferences, and installations
Memoria e Futurismo che ci riunisce in luoghi diversi d’Alessandria, oltre che del Cairo, che ci permette di incontrare un pubblico curioso, e’ nato da una certa filosofia di scambi e di incontri, dalla fedelta’ verso la citta’ di Alessandria e da un profondo desiderio di far conoscere le forme contemporanee dell’arte multimediale. Dal 2001, con progetti quali il Viaggiatore Alessandria-Marsiglia, poi le piattaforme ANIMANET e RAMI, artisti, addetti culturali, insegnanti, ricercatori, esperti di media, hanno creduto a questi progetti e a queste iniziative.
La video arte e’ stata inventata da Nam June Paik e Volf Wostell, all’inizio degli anni 60, da membri del Movimento artistico d’avanguardia Fluxus, promanazione di un altro movimento artistico fondamentale nella storia dell’arte: il Dadaismo. Questi due movimenti certamente non avrebbero avuto luce se non fossero stati preceduti dal Movimento futurista lanciato nel 1909 da Marinetti, tanto che i suoi principi hanno profondamente lasciato il segno in tutti i piu’ grandi movimenti d’avanguardia del XIX secolo. I Futuristi rinunciarono alla separazione tra l’arte e la vita (a loro l’invenzione della performance), propugnando la fine di tutti i classicismi, la rivoluzione formale permanente. Essi volevano essere in linea con la rivoluzione tecnologica d’allora che trasformava radicalmente i modi di vita e di relazione con l’ambiente.
Memoria e Futurismo propone lo studio delle basi della video arte all’interno dei manifesti futuristi e l’installazione Disposition, creazione numerica che fa riferimento ai supporti della memoria passando da Istanbul, Alessandria e Marsiglia. Alessandria, citta’ dellla memoria e’ anche citta’ dell’infanzia e della giovinezza di Marinetti, nato il 22 dicembre 1876 ad Alessandria e di altri importanti artisti degli inizi del 20° secolo. Parallelamente proiezioni, incontri sul tema « Cinema, video arte e futurismo » e due ateliers aperti a giovani artisti e realizzatori. L’atelier « Alla ricerca di Marinetti » e’ proposto da Marc Mercier, artista direttore di Instants Video con Giovanni Lista, storico del Futurismo. L’altro, centrato sull’edizione multimediale interattiva diretto da Renaud Vercey e Bruno Voillot, autori di Disposition, con Mohamed Youssef, artista plastico e multimediale.
After starting the FD fan, why we maintain 30% air flow and -20 mmWC furnace draft? why not above or below this range?
Hi guys,
My customer has just requested me to design a grounding system for his generators.
Basically, he has 6 generators ( 6.6kV) which will operate in parallel.
From his single line diagram and specifications, he wants the grounding to be done indivually for each genera
In ID fan, regulating vane,inlet guide vane both are same or different? if it is different where it is located? what is the purpose of the two vanes?
If te capacity of turbo-generator is 3,500 kW, which is a more proper choice for the generator ? 11 KV or 415 V AC
Hi, anyone can tell me where can get control circuit diagram of motor for 220 V/ 4KVA motor drive automatic varic.?
hello i have a windmill with a generator that give`s me from 0 to 33 volt dc.
i want to load up a accu at 12v dc at all time`s even the time that the voltage is below 12 v dc.
can enywhone explane how to do that ,help me
i have LT GENERATOR .5 M,BUT POWER FACTOR (P.F) at load .7 need design power factor correction 200kvar
ask connection power factor correction, parallel after main circuit breaker
My customer wants to recycle water which has TDS about 300 after gravity settling in clarifier (outlet is below 20ppm). His worry is about possible deposits in the pipe lines due to TDS in water.
Question:
1. will this TDS level will cause any deposition in pipelines at normal te
Keith's 15 Dec note: Charles Bolden is scheduled to meet with President Obama at the White House in the oval office on Wednesday at 3:05 pm EST. The topic for discussion is the Augustine Commission's findings and their "non-recommendation recommendations".
Keith's 16 Dec update: Don't look for a flurry of press releases, etc. coming from this meeting today. Alas, while many at NASA HQ (and the White House) would prefer that all the details of NASA's new White House direction stay under wraps until the FY 2011 budget comes out in Feb. 2010, it is almost a certainty that things will start dribbling out soon. Stay tuned.
Keith's 16 Dec update: The following brief exchange happened during a routine White House press briefing with White House Press Secretary Robert Gibbs:
"Question: The President met with the NASA Administrator today to talk about the Constellation program. Are the two in agreement now on about what to do with that program going forward? Has a decision --
Robert Gibbs: I have not gotten a read out from the meeting. But we're trying to see what has come of their discussions. I don't know that we'll have a ton on this today. Obviously, the budget is being put together for next year. I know the most previous budget that was passed represented an increase in spending for NASA - and the President believes that NASA plays a vital role going forward.
Question: Has that decision been reached yet? Were the two [of them] were talking about it? Prior to the meeting, has the decision about Constellation --
Robert Gibbs: Let me get a readout from the meeting before I --"
Obama, NASA chief talk about goals, panel's options, Huntsville Times
"Administrator Bolden met this afternoon with President Obama in the Oval Office," [NASA Associate Administrator Morrie] Goodman said in an e-mail. "The two discussed the Augustine Commission's study and analysis of the existing space program, which highlighted challenges. They also discussed options for how the country might improve its future human spaceflight activities. "The president re-confirmed his commitment to human spaceflight and space exploration as well as his goal of ensuring that the nation is on a sustainable path to achieving our aspirations in space."
iGo's three new products, the Power Smart Tower, Power Smart Wall and Laptop Charger, detect when a plugged-in device isn't being used and then shut off the power being drawn from the wall—which could equal huge energy savings.
The Power Smart Tower has four of these Green outlets, four normal outlets (in case you have stuff that needs to draw power all the time) and two USB jacks, and will run $80. Its little brother, the Power Smart Wall, is meant to be wall-mounted, and has half the number of outlets and no USB jacks. It'll retail for $30 (this one is pretty tempting to me personally—seems fairly priced and a nice easy way to save some power). Finally, the diminutive laptop charger, helpfully named Laptop Charger, only charges your computer when it actually needs it, and offers an additional plug for a mobile device. That one'll run you $100. All three products are available now from iGo's site. [Krunker via Ubergizmo]
