Questões de Concursos Inglês

NASA Researchers Studying Advanced Nuclear Rocket Technologies

January 9, 2013

By using an innovative test facility at NASA’s Marshall Space Flight Center in Huntsville, Ala., researchers are able to use non-nuclear materials to simulate nuclear thermal rocket fuels - ones capable of propelling bold new exploration missions to the Red Planet and beyond. The Nuclear Cryogenic Propulsion Stage team is tackling a three-year project to demonstrate the viability of nuclear propulsion system technologies. A nuclear rocket engine uses a nuclear reactor to heat hydrogen to very high temperatures, which expands through a nozzle to generate thrust. Nuclear rocket engines generate higher thrust and are more than twice as efficient as conventional chemical rocket engines.

The team recently used Marshall’s Nuclear Thermal Rocket Element Environmental Simulator, or NTREES, to perform realistic, non-nuclear testing of various materials for nuclear thermal rocket fuel elements. In an actual reactor, the fuel elements would contain uranium, but no radioactive materials are used during the NTREES tests. Among the fuel options are a graphite composite and a “cermet” composite - a blend of ceramics and metals. Both materials were investigated in previous NASA and U.S. Department of Energy research efforts.

Nuclear-powered rocket concepts are not new; the United States conducted studies and significant ground testing from 1955 to 1973 to determine the viability of nuclear propulsion systems, but ceased testing when plans for a crewed Mars mission were deferred.

The NTREES facility is designed to test fuel elements and materials in hot flowing hydrogen, reaching pressures up to 1,000 pounds per square inch and temperatures of nearly 5,000 degrees Fahrenheit - conditions that simulate space-based nuclear propulsion systems to provide baseline data critical to the research team.

“This is vital testing, helping us reduce risks and costs associated with advanced propulsion technologies and ensuring excellent performance and results as we progress toward further system development and testing,” said Mike Houts, project manager for nuclear systems at Marshall.

A first-generation nuclear cryogenic propulsion system could propel human explorers to Mars more efficiently than conventional spacecraft, reducing crews’ exposure to harmful space radiation and other effects of long-term space missions. It could also transport heavy cargo and science payloads. Further development and use of a first-generation nuclear system could also provide the foundation for developing extremely advanced propulsion technologies and systems in the future - ones that could take human crews even farther into the solar system.

Building on previous, successful research and using the NTREES facility, NASA can safely and thoroughly test simulated nuclear fuel elements of various sizes, providing important test data to support the design of a future Nuclear Cryogenic Propulsion Stage. A nuclear cryogenic upper stage - its liquid- hydrogen propellant chilled to super-cold temperatures for launch - would be designed to be safe during all mission phases and would not be started until the spacecraft had reached a safe orbit and was ready to begin its journey to a distant destination. Prior to startup in a safe orbit, the nuclear system would be cold, with no fission products generated from nuclear operations, and with radiation below significant levels.

“The information we gain using this test facility will permit engineers to design rugged, efficient fuel elements and nuclear propulsion systems,” said NASA researcher Bill Emrich, who manages the NTREES facility at Marshall. “It’s our hope that it will enable us to develop a reliable, cost-effective nuclear rocket engine in the not-too-distant future."

The Nuclear Cryogenic Propulsion Stage project is part of the Advanced Exploration Systems program, which is managed by NASA’s Human Exploration and Operations Mission Directorate and includes participation by the U.S. Department of Energy. The program, which focuses on crew safety and mission operations in deep space, seeks to pioneer new approaches for rapidly developing prototype systems, demonstrating key capabilities and validating operational concepts for future vehicle development and human missions beyond Earth orbit.

Marshall researchers are partnering on the project with NASA’s Glenn Research Center in Cleveland, Ohio; NASA’s Johnson Space Center in Houston; Idaho National Laboratory in Idaho Falls; Los Alamos National Laboratory in Los Alamos, N.M.; and Oak Ridge National Laboratory in Oak Ridge, Tenn.

The Marshall Center leads development of the Space Launch System for NASA. The Science & Technology Office at Marshall strives to apply advanced concepts and capabilities to the research, development and management of a broad spectrum of NASA programs, projects and activities that fall at the very intersection of science and exploration, where every discovery and achievement furthers scientific knowledge and understanding, and supports the agency’s ambitious mission to expand humanity’s reach across the solar system. The NTREES test facility is just one of numerous cutting-edge space propulsion and science research facilities housed in the state-of- the-art Propulsion Research & Development Laboratory at Marshall, contributing to development of the Space Launch System and a variety of other NASA programs and missions.

Available in: http://www.nasa.gov

The uses for oil

Oil is the largest source of liquid fuel and, in spite of attempts to develop synthetic fuels, world consumption of oil products in increasing.
The oil industry is not much more than a hundred years old. It began when the first oil well was drilled in 1859. In the early days, oil was used to light houses because there was no electricity and gas was very scarce. Later, people began to use oil for heating too.
Most industries use machinery to make things. Every machine needs oil in order to run easily. Even a small clock or watch needs a little oil from time to time.
The engines of many machines use oil fuels petrol, kerosene or diesel. Cars, buses, trucks, tractors, and small aircraft use petroleum chemicals: synthetic rubber, plastics, synthetic fiber materials for clothes and for the home, paints, materials which help to stop rust, photographic materials, soap and cleaning materials (detergents), drugs, fertilizers for farms and gardens, food containers, and may others.
In 1900 the world’s oil production was less than 2 million tons a year. Today the oil industry is one of the world’s largest and most important suppliers of raw materials.

House Approves Higher Debt Limit Without Condition
By JONATHAN WEISMAN and ASHLEY PARKER
Feb. 11, 2014

WASHINGTON - Ending three years of brinkmanship in which the threat of a devastating default on the nation’s debt was used to wring conservative concessions from President Obama, the House on Tuesday voted to raise the government’s borrowing limit until March 2015, without any conditions.
The vote - 221 to 201 - relied almost entirely on Democrats in the Republican-controlled House to carry the measure and represented the first debt ceiling increase since 2009 that was not attached to other legislation. Only 28 Republicans voted yes, and only two Democrats voted no.
Simply by holding the vote, Speaker John A. Boehner of Ohio effectively ended a three-year Tea Party-inspired era of budget showdowns that had raised the threat of default and government shutdowns, rattled economic confidence and brought serious scrutiny from other nations questioning Washington’s ability to govern. In the process, though, Mr. Boehner also set off a series of reprisals from fellow Republican congressmen and outside groups that showcased the party’s deep internal divisions.
During the October 2013 government shutdown, The Times’s David Leonhardt explained the debt limit and how a failure to raise it could have affected the economy both at home and abroad.
"He gave the president exactly what he wanted, which is exactly what the Republican Party said we did not want,” said a Republican representative, Tim Huelskamp of Kansas, who last year unsuccessfully tried to rally enough support to derail Mr. Boehner’s re-election as speaker. “It’s going to really demoralize the base.”
The vote was a victory for President Obama, Democrats and those Senate Republicans who have argued that spending money for previously incurred obligations was essential for the financial standing of the federal government. “Tonight’s vote is a positive step in moving away from the political brinkmanship that’s a needless drag on our economy,” Jay Carney, the White House press secretary, said in a statement.
"A clean debt ceiling is a complete capitulation on the speaker’s part and demonstrates that he has lost the ability to lead the House of Representatives, let alone his own party,” said Jenny Beth Martin, co-founder of the Tea Party Patriots. “It is time for him to go.”
Senator Harry Reid of Nevada, the majority leader, commended the speaker and promised to pass the bill as soon as possible. “We’re happy to see the House is legislating the way they should have legislated for a long time,” he said.

(Adapted from http://www.nytimes.com/2014/02/12/us/politics/ boehner-to-bring-debt-ceiling-to-vote-without-policy- attachments. html?nl=todaysheadlines&emc=edit_th_2014021 2&_r=0)

   The cost of a cigarette

 Generation Y
By Sally Kane, About.com Guide

Born in the mid-1980"s and later, Generation Y legal professionals are in their 20s and are just entering the workforce. With numbers estimated as high as 70 million, Generation Y (also -1- as the Millennials) is the fastest growing segment of today"s workforce. As law firms compete for available talent, employers cannot ignore the needs, desires and attitudes of this vast generation. Below are a few common traits that define Generation Y.

Tech-Savvy: Generation Y grew up with technology and rely on it to perform their jobs better. Armed with BlackBerrys, laptops, cellphones and other gadgets, Generation Y is plugged-in 24 hours a day, 7 days a week. This generation prefers to communicate through e-mail and text messaging rather than face-to-face contact and -2- webinars and online technology to traditional lecture-based presentations.

Family-Centric: The fast-track has lost much of its appeal for Generation Y who is willing to trade high pay for fewer billable hours, flexible schedules and a better work/life balance. While older generations may view this attitude as narcissistic or lacking commitment, discipline and drive, Generation Y legal professionals have a different vision of workplace expectations and prioritize family over work.

Achievement-Oriented: Nurtured and pampered -3- parents who did not want to make the mistakes of the previous generation, Generation Y is confident, ambitious and achievement-oriented. They have high expectations of their employers, seek out new challenges and are not afraid to question authority. Generation Y wants meaningful work and a solid learning curve

Team-Oriented: As children, Generation Y participated in team sports, play groups and other group activities. They value teamwork and seek the input and affirmation of others. Part of a no-person-left-behind generation, Generation Y is loyal, committed and wants to be included and involved.

Attention-Craving: Generation Y craves attention in the forms of feedback and guidance. They appreciate being kept in the loop and seek frequent praise and reassurance. Generation Y may benefit greatly from mentors who can help guide and develop their young careers.

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