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Comment: Re:140000 Newton (Score 2, Informative) 153

by ikeleib (#27127755) Attached to: Europe's Biggest Amateur Rocket Completes Test-Firing

Saturn V was a 'multi-gear' rocket. To lift off the pad, all 5 main rockets fired. As altitude increased, the center rocket turned off to minimize stress on the rocket (stay subsonic???)

Space shuttle also has multiple speeds. If you remember the Challenger disaster - the last message from ground was "Go with throttle up" Apparently the shuttle was high enough to go full throttle (again) and not worry about aerodynamic stresses.

Most liquid fueled rockets are throttleable. Both the space shuttle and Saturn V's throttle down to avoid putting "too much stress" on the airframe. What this really means, is that they didn't want to put more weight into airframe structure, and instead reduce throttle to the point where the atmosphere thins enough that one can throttle up without surpassing the design strength of the airframe. By the way, this point is called Max-Q and for the space shuttle, it is at 11km in altitude. For the space shuttle main engines, this means they throttle up to 104% of specification power (due to improvements over the years, the SSME maximum safe throttle is actually 109% of specification).

One of the issues with the shuttles solid rocket boosters - they are steerable - allowing insertion into a very precise orbit.

Compare that with the typical home built - solid rocket, that basically goes were you point it...usually...give or take a bit.

The problem with solid rocket motors for space travel is two fold. The first is that they cannot be throttled or turned off. The second is that they are considerably less efficient pound-for-pound than liquid fueled rockets. The typical measure of rocket efficiency is specific impulse, which is measured in seconds. For example, the solid rocket boosters of the shuttle have a specific impulse of 242 seconds, while the space shuttle main engines produce a specific impulse of 363.

Patents

Rewriting a Software Product After Quitting a Job? 604

Posted by kdawson
from the clean-room-white-coats dept.
hi_caramba_2008 writes "We are a bunch of good friends at a large software company. The product we work on is under-budgeted and over-hyped by the sales drones. The code quality sucks, and management keeps pulling in different direction. Discussing this among ourselves, we talked about leaving the company and rebuilding the code from scratch over a few months. We are not taking any code with us. We are not taking customer lists (we probably will aim at different customers anyway). The code architecture will also be different — hosted vs. stand-alone, different modules and APIs. But at the feature level, we will imitate this product. Can we be sued for IP infringement, theft, or whatever? Are workers allowed to imitate the product they were working on? We know we have to deal with the non-compete clause in our employment contracts, but in our state this clause has been very difficult to enforce. We are more concerned with other IP legal aspects."

Comment: Google and OpenOffice.org already happened (Score 4, Informative) 277

by ikeleib (#23661013) Attached to: Why Google Should Embrace OpenOffice.org
Google hired developers to work on OpenOffice.org, but found it difficult to fill all the vacancies. They seemed unwilling to work on the project understaffed and the people they hired now work on other things.

You can see a C|Net article about their hiring from a while back:
http://news.cnet.com/Google-throws-bodies-at-OpenOffice/2100-7344_3-5920762.html
Power

+ - Thin Clients: Eco-Friendly Alternative to PCs->

Submitted by
mrcgran
mrcgran writes "This report is month-old, but still interesting: 'Using thin clients instead of conventional PCs would lower energy consumption by 51 percent and reduce CO2 emissions, concludes a recent study by the Fraunhofer Institute. The study compared thin clients to conventional business PCs. "The financial savings are significant but the impact on cutting CO2 emissions is what's really impressive. Saving 2.45 billion pounds of CO2 emissions would remove the equivalent impact of 106,521 average U.S. households each year."' Lots of Linux thin clients are springing up. Would you replace your conventional PC for one of them?"
Link to Original Source
Databases

+ - LiquiBase Database Refactoring 1.0->

Submitted by
nvoxland
nvoxland writes "After over a year of active development, LiquiBase 1.0 has been released. LiquiBase is a java-based, LGPL, DBMS-independent library for tracking, managing and applying database changes. It is similar to Rail's Active Migrations, but doesn't suffer from the same problems with multiple developers and branches. It also has many unique features such as 30 refactorings, rollback support, and upgrade script SQL-generation."
Link to Original Source

Protein Accelerates Breast Cancer Progression In Animal Models->

From feed by sdfeed
Scientists have shown for the first time that a cytokine called pleiotrophin stimulates the progression of breast cancer in both animal and cell culture models. The study, which tested three separate models to determine the role of inappropriate expression of pleiotrophin, found that it produced striking increases in aggressiveness of the breast cancer cells themselves.
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Spam

+ - Spam: now available in PDF->

Submitted by
choongiri
choongiri writes "If my inbox is anything to go by, there's a new breed of spam on the loose. Last year saw the rise of the image-based penny stock spam — that got around our filters for a while until tools like the FuzzyOCR plugin for SpamAssassin came along. Now it looks like the spammers are taking it to the next level, attaching their spam content as a PDF file. No doubt if this persists we'll see PDF scanning becoming standard practice, although the cost — both in bandwidth and CPU cycles required to do the filtering — will certainly be non-trivial."
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Programming

+ - No iPhone SDK Means No iPhone Killer Apps->

Submitted by iPhoneLover/Hater
iPhoneLover/Hater (666) writes "Gizmodo is running an article analyzing the potential failure of the iPhone as a truly revolutionary platform. The reason: no SDK to harness the true power of Mac OS X and the frameworks contained in Apple's smart cell. From the article: "According to Apple, "no software developer kit is required for the iPhone." However, the truth is that the lack of an SDK means that there won't be a killer application for the iPhone. It also means the iPhone's potential as an amazing computing and communication platform will never be realized. And because of this and no matter how Apple tries to sell it, the iPhone won't make a revolution happen.""
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Portables

+ - Asus Eee PC Hands-On, Competition For The OLPC

Submitted by MojoKid
MojoKid (1002251) writes "Asus made quite a splash at the Computex show last week with the introduction of their Eee PC, a low cost, highly portable machine slated to compete with the OLPC project. At price points of $199 and $299 for 4GB and 8GB Solid State Flash drive equipped models, the Asus Eee PC looks to be formidable. This exclusive first-ever hands-on showcase of the machine shows the two interfaces of its Linux-based operating system as well as its modes of operation, pre-installed open source Office software and other applications like Skype. The ASUS Eee PC will be available world wide, in full production quantities in Q3 this year. It is rumored to have a street date of mid August."
Bug

Apple Safari On Windows Broken On First Day 595

Posted by kdawson
from the bigger-they-come dept.
An anonymous reader writes "David Maynor, infamous for the Apple Wi-Fi hack, has discovered bugs in the Windows version of Safari mere hours after it was released. He notes in the blog that his company does not report vulnerabilities to Apple. His claimed catch for 'an afternoon of idle futzing': 4 DoS bugs and 2 remote execution vulnerabilities." Separately, within 2 hours Thor Larholm found a URL protocol handler command injection vulnerability that allows remote command execution.

Prediction is very difficult, especially of the future. - Niels Bohr

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