Since the Model S went into production last year, there have been more than a quarter million gasoline car fires in the United States alone, resulting in over 400 deaths and approximately 1,200 serious injuries (extrapolating 2012 NFPA data). However, the three Model S fires, which only occurred after very high-speed collisions and caused no serious injuries or deaths, received more national headlines than all 250,000+ gasoline fires combined. The media coverage of Model S fires vs. gasoline car fires is disproportionate by several orders of magnitude, despite the latter actually being far more deadly.
Reading the headlines, it is therefore easy to assume that the Tesla Model S and perhaps electric cars in general have a greater propensity to catch fire than gasoline cars when nothing could be further from the truth.
What does current look like on a quantum level?
To understand how current flows in a material you first have to understand electrons behave in a material. The key feature of solid state physics is that many materials are crystals. This means that the atoms are spaced periodically. As you mention, band structures are the way that we summarize the effect of this periodic potential. Basically, a band structure just relates an electrons momentum p=mv=hbar k to its energy. The momentum can be positive or negative, the sign only denotes direction. In free space this is very boring, Energy=m v2 /2 = p2 /2m=hbar k2 /2m. When you throw in a periodic potential, this becomes modified and results in bands. Actually calculating band structures is quite difficult. The key idea is that there are ranges of energy where the electron can live and ranges of energy where the electron cannot live.
via What does current look like on a quantum level? : askscience.
Snapchat Spurned $3 Billion Acquisition Offer from Facebook
In June, Snapchat raised $60 million from investors including Institutional Venture Partners; that round valued the company at $800 million.
Three months later, Snapchat said its usage had nearly doubled, to 350 million messages or “snaps” per day, up from 200 million in June.
via Snapchat Spurned $3 Billion Acquisition Offer from Facebook – Digits – WSJ.
Newegg hurtles toward Texas showdown with famed “patent troll”
But Jones didn’t invent SSL; nor did he invent RC4, an algorithm invented in 1987, two years before the filing date of the Jones patent.
Whatever his invention is, it came before the World Wide Web, which was made available to everyone in 1993. Jones filed for his patent in 1989, and it uses some distinctively pre-Web vocabulary; describing encryption via modems and phone lines.
via Newegg hurtles toward Texas showdown with famed “patent troll” | Ars Technica.
By claiming such common encryption, the TQP patent is essentially a “we-own-the-Internet” patent. Spangenberg declined to speak to Ars for this story, but in an August interview he said the TQP licensing campaign has reaped around $40 million in revenue.
Artificial Photosynthesis Made Practical
If you want hydrogen to power an engine or a fuel cell, it’s far cheaper to get it from natural gas than to make it by splitting water. Solar power, however, could compete with natural gas as a way to make hydrogen if the solar process were somewhere between 15 and 25 percent efficient, says the U.S. Department of Energy. While that’s more than twice as efficient as current approaches, researchers at Stanford University have recently developed materials that could make it possible to hit that goal. The work is described in the journal Science.
via Artificial Photosynthesis Made Practical | MIT Technology Review.
FCC: Unlock or We Regulate
The FCC’s new chairman, Tom Wheeler, is taking the wireless operators to task over their cellphone unlocking policies in his first month on the job. He has told them to get moving on addressing consumers’ rights to unlock their phones once their contracts are fulfilled — or they will face regulation.
inForm Dynamic Shape Output
The mechanism of MIT’s new shapeshifting output device is remarkably simple. It is based on the well known pin screen devices that you can use to take a 3D impression of an object. A 2D plate of pins can be moved to create a surface.
Should arrays start with 0 or 1?
“Should array indices start at 0 or 1? My compromise of 0.5 was rejected without, I thought, proper consideration.” — Stan Kelly-Bootle
Microsoft Warns Customers Away From RC4, SHA-1
RC4 is among the older stream cipher suites in use today, and there have been a number of practical attacks against it, including plaintext-recovery attacks. The improvements in computing power have made many of these attacks more feasible for attackers, and so Microsoft is telling developers to drop RC4 from their applications.
via Microsoft Warns Customers Away From RC4, SHA-1 | Threatpost | The First Stop For Security News.
The software company also is recommending that certificate authorities and others stop using the SHA-1 algorithm.
Your visual how-to guide for SELinux policy enforcement
Note: SELinux does not let you side step DAC Controls. SELinux is a parallel enforcement model. An application has to be allowed by BOTH SELinux and DAC to do certain activities. This can lead to confusion for administrators since the process gets Permission Denied. Administrators see Permission Denied means something is wrong with DAC, not SELinux labels.
via Your visual how-to guide for SELinux policy enforcement | opensource.com.\
DAC=Discretionary Access Control
SELinux is a powerful labeling system, controlling access granted to individual processes by the kernel. The primary feature of this is type enforcement where rules define the access allowed to a process is allowed based on the labeled type of the process and the labeled type of the object.
For regular users SELinux can be a complete PITA which usually needs to be disabled or set to just log the violation only. I recall in past years installing some service and trying to figure out why it wouldn’t work until the logs revealed I didn’t have things set up in a way SELinux wants. Currently I try and minimize SELinux violations because it seems like it has a point most of the time.