Rationalist, Political and Economic junkie, Progressive, Skeptic, Linux/OSX enthusiast, and programmer.
777 stories
·
9 followers

Dollar General Hits a Gold Mine in Rural America

1 Comment and 2 Shares
On a Friday in April, Bob Tharp, the mayor of Decatur, Ark., takes me to see what used to be the commercial heart of his town. There isn’t much to look at…
Read the whole story
chrishiestand
1 day ago
reply
“Essentially what the dollar stores are betting on in a large way is that we are going to have a permanent underclass in America. It’s based on the concept that the jobs went away, and the jobs are never coming back, and that things aren’t going to get better in any of these places.”
San Diego, CA, USA
acdha
2 days ago
reply
Washington, DC
Share this story
Delete

Pumping liquid metal at 1,400°C opens the door for better solar thermal systems

3 Comments and 5 Shares
  • "Georgia Tech Graduate Student Caleb Amy holds a ceramic gear developed for a pump able to transfer molten tin at more than 1,400° Celsius."

    Christopher Moore, Georgia Tech

  • From Georgia Tech: "This image shows liquid metal flowing at 1400° Celsius in the laboratory of Asegun Henry at Georgia Tech. Even though all the surrounding materials are glowing, the tin remains reflective and the ripples from the pool of tin below are visible via reflections from the stream.

    Caleb Amy

  • "Georgia Tech Graduate Student Caleb Amy shows how two ceramic gears mesh in a pump developed to transfer molten tin at more than 1,400° Celsius."

    Christopher Moore, Georgia Tech

  • "Graduate Student Caleb Amy pours molten tin into a crucible in the laboratory of Asegun Henry at Georgia Tech. A new ceramic-based pump designed and tested at Georgia Tech was used to transfer molten tin at more than 1,400° Celsius."

    Christopher Moore, Georgia Tech

Researchers from the Georgia Institute of Technology, Stanford, and Purdue University have built a ceramic mechanical pump that can move liquid metal as hot as 1,673K (that is, about 1,400 degrees Celsius). Usually, the temperature of liquid metals that you can pump tends to cap out at 1,300K (1,027 degrees Celsius) because there are few pump-building materials that will stay solid and chemically stable beyond that. Those materials that exist tend to crack or break quickly under the stress of such heat.

But this new pump, made of carefully engineered ceramic, could be good news for concentrated solar power, as well as accompanying thermal energy storage.

An example of these sorts of systems is SolarReserve’s 110 MW Crescent Dunes plant outside of Tonopah, Nevada. The facility consists of an array of heliostats—or panels that reflect sunlight onto a thermal tower—and a molten salt tank. The molten salt is pumped to the thermal tower and captures the heat from the sunlight projected on the tower. It is then stored at 566 degrees Celsius (1,050 degrees Fahrenheit) and used to transfer heat through a heat exchanger to a working fluid that spins a conventional turbine, generating electricity.

This latest research could improve that system by allowing operators to exchange that molten salt for liquid tin, which has a higher thermal conductivity than molten salt and, at 1,673K, could supply more energy to a system with less effort. In fact, the researchers say, “the use of molten metals instead of fluids such as oils and salts that are electrically insulating can result in an increase in the heat transfer coefficient of two to three orders of magnitude.”

The trick to creating the ceramic pump lay in careful engineering of the pump itself. Materials had to be chosen to accommodate for expansion and contraction of the pump with heat, and an appropriate material for sealing the pump was also necessary. The researchers used graphite for piping, joints, and seals, as well as a material called Shapal (“a machinable aluminium-nitride-rich composite”) because it had a similar coefficient of expansion to graphite under heat. Tungsten was used for the outside of the sealed region.

The external gear pump was then built with the pump's gear teeth and the motor intentionally misaligned at room temperature; when the pump experienced very high temperatures it would expand into proper alignment. The pump expanded more than 1mm vertically while in operation.

To accommodate very high temperature liquid metal, the atmosphere inside the pump was replaced with inert N2, which the researchers say “can also be used at the industrial scale.”

The pump system was tested at an average temperature of 1,473K (1,200 degrees Celsius)—with peak temperatures above 1,673K (1,400 degrees Celsius)—for 72 hours. The researchers noted that the temperature of the liquid metal “was a result of limited heater power and is not a fundamental bound on the pump or other system components.” After 72 hours the test was stopped, and there were no component failures during the test or upon cooling. Although the gears “experienced visible wear,” the researchers offered some design suggestions that would improve the lifetime of the components in future tests. “Shaft wear was reduced by more than an order of magnitude from earlier tests simply by polishing the shafts,” the paper said.

The high volumetric energy density of liquid tin would allow a relatively small pump to be used at a full-scale power plant. The researchers estimate that using very hot liquid metal in their pump would result in “a relative increase in efficiency of approximately 50 percent” at concentrated thermal solar plants, “reducing costs by 20 percent–30 percent.”

One thing worth noting is that this research was funded by the Advance Research Projects Agency-Energy (ARPA-E). The agency distributes grants to institutions like Georgia Institute of Technology to advance energy-related technology, especially favoring projects that might be uneconomic for private companies to fund. But projects like this may not be possible in the future, as the Trump administration has asked for all ARPA-E funding to be cut in the 2018 budget.

Nature, 2017. DOI: 10.1038/nature24054  (About DOIs).

Listing image by Christopher Moore, Georgia Tech

Read the whole story
chrishiestand
4 days ago
reply
“One thing worth noting is that this research was funded by the Advance Research Projects Agency-Energy (ARPA-E). The agency distributes grants to institutions like Georgia Institute of Technology to advance energy-related technology, especially favoring projects that might be uneconomic for private companies to fund. But projects like this may not be possible in the future, as the Trump administration has asked for all ARPA-E funding to be cut in the 2018 budget.”
San Diego, CA, USA
acdha
6 days ago
reply
Washington, DC
Share this story
Delete
1 public comment
satadru
6 days ago
reply
"But projects like this may not be possible in the future, as the Trump administration has asked for all ARPA-E funding to be cut in the 2018 budget."
New York, NY

Have dirt that could impeach Trump? Larry Flynt will pay you $10 million.

1 Comment

Read the whole story
chrishiestand
6 days ago
reply
At first, I didn't think this could possibly change anything. But actually the type of person I imagine doing business with Trump might be interested in a deal like this.
San Diego, CA, USA
Share this story
Delete

PornHub Uses Computer Vision To ID Actors, Acts In Its Videos

1 Share
Baron_Yam shares a report from TechCrunch, which details PornHub's use of machine learning to ID actors and acts in its videos: The computer vision system can identify specific actors in scenes and even identifies various positions and attributes. While it is obviously very difficult to describe the feature set for a family audience, the system can identify individual performers in real time -- in the demo here it recognizes one performer even from the side -- and it can also identify sex acts. Facial detection is nothing new, even for mobile devices, but this system goes one step further by categorizing videos and images based on various attributes. This means you'll be able find favorites by name or characteristics, a feat that once require prodigious amounts of data entry. "So far we've used the model on about 500k featured videos which includes user submitted and we plan to scan the whole library in the beginning of 2018," said Price. "Very shortly, the technology will also be used to detect various sex positions / categories and be able to properly tag them as well."

Read more of this story at Slashdot.

Read the whole story
chrishiestand
9 days ago
reply
San Diego, CA, USA
Share this story
Delete

Google Will Hit 100 Percent Renewable Energy This Year

1 Comment
An anonymous reader quotes a report from Inverse: Google has announced that after 10 years a carbon-neutral company, it will be able to brag running on entirely renewable energy at the end of 2017. That means that all of the electricity the company consumes in both its data centers and offices are provided by wind and solar energy. Announced in Google's 2017 environmental report, Google says it has created "new energy purchasing models that others can follow" and that "we've helped drive wide-scale global adoption of clean energy." In addition to being an obvious PR boon, the company says its mission of full sustainability fits in with its larger mission. (It also makes the fact that as recently as 2015 Google alone reportedly consumed as much energy as the entire city of San Francisco in a year way more palatable.) One step the company has recently taken in marrying its ethos of sustainability with its products is a new initiative to equip Google Street View vehicles with air quality sensors. In addition to its goal of being run by renewable energy, Google is also working on achieving zero waste to landfill. Nearly half of the company's 14 data centers have already reached this goal, according to Google executive Urs Holzle's 2017 Google Environmental report released on Tuesday.

Read more of this story at Slashdot.

Read the whole story
chrishiestand
9 days ago
reply
Good on google.
San Diego, CA, USA
Share this story
Delete

The End of the Road

1 Comment and 2 Shares

The end of the road!

If you’ve been following along with major news outlets over the past few months, DreamHost has been in something of a deadlock with the Department of Justice.

Why Bother?

At risk is the personally identifiable information of many, many thousands of internet users who chose to visit or otherwise interact with DisruptJ20.org, a website created and maintained by one of our customers.

While we regularly work with law enforcement and hand over certain types of data as part of various ongoing investigations, this particular request for customer data was overly broad, and we objected to it on those terms.

The court chose, in this case, to act as an intermediary between DreamHost and the Department of Justice to ensure that user rights remained protected and that First and Fourth Amendment protections were respected.

We had been awaiting Chief Judge Morin’s final order, which would spell out the exact nature of the data that DreamHost would be required to hand over while mulling over a decision to appeal the court’s general order.

Today’s Order

Today Chief Judge Morin of the Washington D.C. Superior Court issued the court’s final order, and we’re elated to see significant changes that will protect the constitutional rights of innocent internet users worldwide.

DreamHost DOJ Records Request

Under this order, we now have the ability to redact all identifying information and protect the identities of users who interacted with <a href="http://disruptj20.org" rel="nofollow">disruptj20.org</a> before handing over any data to the court. Chief Judge Morin acknowledged that the government “does not have the right to rummage through the information contained on DreamHost’s website” to “discover the identity of . . . individuals not participating in alleged criminal activity.”

The new order is a far cry from the original warrant we received in July and validates our decision to raise questions about the original order.

We Saw Something, so We Said Something

We are now required to hand over a drastically reduced amount of data to the government and will redact any identifying information from every scrap of it that relates to non-subscribers.

The Department of Justice will have to submit proposed search protocols and procedures (and the court will have to review and approve these) before the DOJ can begin a detailed review of the redacted data.

DreamHost DOJ Records RequestThe DOJ will then have to file an itemized list of information which it believes constitutes evidence of D.C. Code §22-1322 (DC’s rioting statute) and call out the specific reasons why the data is relevant to the DOJ’s investigation with the court.

Finally, the court must find probable cause that the requested data is “evidence of criminal activity” without identifying innocent users of <a href="http://disruptj20.org" rel="nofollow">disruptj20.org</a>. Only then will the DOJ be able to obtain non-redacted data from DreamHost.

We applaud this course of action as it goes a long way toward negating any fears of a “digital dragnet” and targets individual, specific users to whom probable cause has been found by the court. The contact information of simple website visitors, journalists, historians, and any other users who may have interacted with the DisruptJ20 website with innocent intentions is now explicitly protected.

Absent a finding by the court that probable cause of criminal activity exists, the government will not be able to uncover the identities of many thousands of website users. There are also quite a few modifications within the court’s order that further reduce the government’s ability to review unrelated data.

Appeal?

As it stands today, the sum total of requested data in this case very closely aligns with hundreds of other government requests that DreamHost has received, and complied with lawfully, in the past.

We do not intend to appeal the court’s ruling.

There’s really no need. Any sweeping requests for data that could personally identify website visitors not directly related to an ongoing criminal investigation are now off the table. It’s sort of a moot point!

The law makes it clear that the Department of Justice does have a right to request some customer information throughout the course of ongoing criminal investigations. We respect that right and appreciate the court’s oversight in this case as a step to help protect users and reign in what we considered to be a problematic, overly-broad records request.

Next Steps

We’re preparing to compile the mass of data requested by the court.

As part of that effort, we plan to pore over every single email and scrap of data that we’ve collected to redact any information that could be used to identify anyone who may have visited or otherwise used <a href="http://DisruptJ20.org" rel="nofollow">DisruptJ20.org</a>. This excludes, of course, our own customer who is a confirmed subject of an ongoing investigation.

To be clear, DreamHost has been deputized to redact sensitive information. No government employee will see this data until we’ve personally gone over it with a fine-toothed comb, and our commitment to user privacy is strong and unwavering.

We see this as an absolute victory not just for DreamHost, but for online service providers throughout America and for internet users around the world. As a result of this ruling, internet users retain the ability to simply browse the internet without fear of being swept up in a criminal probe.

Thank you for your very vocal support over the last few weeks.

Media Requests

Members of the media seeking comment, please email privacy@dreamhost.com with questions or requests.

Previously…

Read the whole story
chrishiestand
9 days ago
reply
Applause
San Diego, CA, USA
acdha
10 days ago
reply
Washington, DC
Share this story
Delete
Next Page of Stories