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BJs Wholesale Black Friday ad leaks with laptop, desktop, tablet deals



BJs Wholesale Club Black Friday ad

Competing with rivals Costco and Sam’s Club, BJs Wholesale Club is a members only warehouse chain with deals on a wide range of products, including computers. Costco’s Black Friday ad has already posted online, so how do BJs’ Black Friday deals compare now that its ad has leaked?

Like Costco, BJs is touting an Apple iPad deal in its ad, but it’s taking a slightly different approach than its competitor. While Costco is taking $80 off the base 9.7-inch iPad, BJs is slicing $80 from the 128GB version as a doorbuster starting at 7 a.m. on Black Friday, lowering the price to $349.99. Another tablet doorbuster is the Amazon Kindle Fire 7, which will be available for $29.99, just like at Target. Rounding out the tablet deals, starting November 16 BJs is discounting the Samsung Galaxy Tab A, with the 8-inch model bundled with 16GB microSD card $50 less at $129.99 and the 10.1-inch model with bonus 32GB microSD card at $149.99. BJs claims that’s $120 off, but you can buy just the tablet itself elsewhere for under $200 right now.

A final doorbuster is the Dell Inspiron 11 2-in-1 with AMD A6 processor, 4GB of RAM, 32GB of storage, and 11.6-inch touchscreen display for $179.99. However, Dell itself is offering a version with similar specs as a doorbuster of its own for a better price of $149.99. Other convertible laptop specials include an 11.6-inch Acer Aspire Spin with 4 gigs of RAM, 64GB of storage and Intel Celeron processor for $219.99, and the HP Envy x360 with Intel Core i5 CPU, 8GB of memory, a 256GB solid-state drive, and 15.6-inch full HD touchscreen for $579.99, $220 off BJs’ current price.

Three more HP laptops will be on sale on Black Friday, starting with the HP Stream 14 with Intel Celeron N3060 processor, 4GB of RAM, 32GB of storage, and 14-inch display for $199.99. Note that that’s more than what Amazon sells it for today ($196), however, if you’re getting the gray version. A better deal is the HP 15-da0079nr, which gets a $150 price cut from its $599.99 regular price for a notebook with Core i7-7200U CPU, 8GB of memory, 1TB hard drive, and 15.6-inch screen. Like the HP Pavilion 15-ck074nr (Core i5-8250U, 8GB of RAM, 1TB hard drive, 15.6-inch full HD display) is sold out online on the BJs website, but will be $170 off the listed price on Black Friday.

Finally, BJs has deals on a pair of desktops listed in its Black Friday, though the Acer Aspire special starts on November 16. That tower comes with the latest Core i5-8400 processor, terabyte hard drive and a whopping 24GB of RAM for $399.99 ($150 off). If you prefer an all-in-one PC instead, the HP 24-f0051 fits an Intel Pentium chip, 8GB of RAM, 1TB hard drive, and a 23.8-inch full HD touchscreen into a single package for $529.99, $70 off the current price (not $150 as mentioned in the ad).

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The art and science of boarding an airplane in a pandemic



Enlarge / During the pandemic, several airlines have switched boarding procedures to create more distance between passengers.

Nicholas Economou | NurPhoto | Getty Images

Jason Steffen studies planets in other solar systems. His most famous work—OK, second-most famous work—was with NASA’s Kepler Mission, a survey of planetary systems. But you’re more likely to have heard of Steffen, a professor at the University of Nevada at Las Vegas, in a very different context: as a student of the airplane boarding process. Years ago, after waiting in yet another line on a jam-packed jetway, the physicist thought to himself, “There has to be a better way than this.”

Airlines are invested in boarding times—and to a lesser extent, offboarding—because time equals money. Flying people around the world is a low-margin business, and the faster you can get a flight loaded, into the air, and then emptied on the ground, the faster you can get the next round of paying customers into the air.

In 2008, Steffen published a paper detailing his way, which has become known as the Steffen method. Forget the point-counters in business class. Forget the smug airline-branded credit card wielders with priority boarding. Forget even the first -class passengers—the complimentary champagne can wait. The fastest way to board an airplane, he concluded, is to allow many people to do many boarding tasks at once. Start with the person in the window seat in the last row on the right side. The person in the third-to-last window seat goes next, allowing time to swing items into the overhead bin. Then the person in the fifth-to-last window seat, and so on until the right side fills up. Then the left side. Then the same pattern for middle seats. Then the aisle. Yeah, a little complicated.

It’s been over a decade, and maybe it won’t surprise you to learn that no airlines have fully gone for the Steffen method. In fact, there’s a subgenre of global researchers—engineers, physicists, computer scientists, cyberneticists, and economists—who search for more optimal ways to cram crowds onto flying metal tubes. They’ve devised at least 20 methods to get people onto planes. But for many reasons—airline finances, airport infrastructure, technological shortcomings—their research has mostly fallen on deaf ears. In 2013, the Dutch airline KLM experimented with a modified Steffen method boarding process, but the company later said the trial had no “tangible additional benefit.”

Now a global pandemic has done the seemingly impossible: shaken up airplane boarding procedures. Along with requiring masks, providing hand sanitizer, and, in some cases, banning passengers from middle seats, many airlines have created boarding and deboarding processes that try to avoid packing flyers too closely together.

Delta, which previously boarded passengers according to ticket classes and mileage club memberships, is loading the airplane back to front, so that flyers don’t pass by others as they make their way to their seats. After preboarding families and passengers that need extra time, United is going back-to-front too. Even Southwest, famous for letting passengers choose their seats, is only letting 10 passengers on at a time, instead of the usual 30. The process is certainly slower, but Southwest, and other airlines, have far fewer passengers these days.

Researchers pushing for smarter approaches to getting on airplanes are hoping for more change. Big changes in aviation tend to only happen when people die or get hurt, says Michael Schultz, who studies air transportation at Technische Universität Dresden. The airlines “try to learn what’s going wrong, and then they try to improve,” he says.

With that in mind, Schultz has been working since last spring with colleagues around the world to identify and simulate the fastest—and safest—way to get people onto and off airplanes right now. He hopes the pandemic pushes airlines to update their technology, so that they’re able to board passengers dynamically, pushing an alert to a passenger’s smartphone when it is their turn to board. He thinks a connected aircraft cabin filled with sensors could help crews direct flyers through often-hectic deboardings too.

“Airlines are dealing with a very precious balancing act,” says Martin Rottler, an aviation veteran who now runs his own consultancy. “They need to balance efficiency with customer satisfaction, and now they need to add on safety.”

Using simulations, researchers devised a boarding method that balances airline efficiency with passenger safety during a pandemic.

Another team of researchers, divided between Bucharest, Romania and Potsdam, New York, think they’ve hacked the perfect mix. They call it the “WilMA back-to-front offset-2,” and it boards back to front, by rows, with the window seats first. The method might occasionally see a passenger on her way back briefly pass someone already sitting at the window. But it threads the needle, the researchers say, between safety and efficiency.

In fact, the boarding process is a little like what lots of airlines are doing now. “They’re just not quite fine-tuning the method” to make it even easier, says John Milne, an engineering management professor at Clarkson University who worked on the research. It’s high time, in other words, for the academic plane-boarding obsessives, not the business people, to be in charge for a change.

This story originally appeared on

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What’s the technology behind a five-minute charge battery?



Building a better battery requires dealing with problems in materials science, chemistry, and manufacturing. We do regular coverage of work going on in the former two categories, but we get a fair number of complaints about our inability to handle the third: figuring out how companies manage to take solutions to the science and convert them into usable products. So, it was exciting to see that a company called StoreDot that was claiming the development of a battery that would allow five-minute charging of electric vehicles was apparently willing to talk to the press.

Unfortunately, the response to our inquiries fell a bit short of our hopes. “Thank you for your interest,” was the reply, “we are still in pure R&D mode and cannot share any information or answer any questions at the moment.” Apparently, the company gave The Guardian an exclusive and wasn’t talking to anyone else.

Undeterred, we’ve since pulled every bit of information we could find from StoreDot’s site to figure out roughly what they were doing, and we went backwards from there to look for research we’ve covered previously that could be related. What follows is an attempt to piece together a picture of the technology and the challenges a company has to tackle to take research concepts and make products out of them.

The need for speed

To an extent, StoreDot is using ideas that have been floating around research labs and startups for years, but it’s taking a bit of a risk by using these ideas in a way that’s different from their apparent promise. The bet that StoreDot is making is that it’s not the absolute charge range of an electric vehicle that matters; it’s how quickly you can extend that range. So, while it’s leveraging research on technologies that allow greater capacity in lithium ion batteries, it’s turning around and sacrificing some of that capacity in order to make charging faster.

Put differently, the bet is that people would rather add 300km to the range of their car in five minutes than have a car with a 600km range that takes an hour to fully charge.

What are the implications of that bet at the hardware level? They’re mostly dictated by heat management. As anyone who’s plugged in a low-charge laptop while it’s sitting on their lap knows, charging a battery produces a lot of heat. Charging it faster produces even more. To deal with this heat, StoreDot is essentially producing a diffuse battery with lots of space in between individual cells, as you can see at the four minute mark of this video (embedded below). The cells have significant gaps between them, and the battery housing has holes that allow airflow between them. It’s charged in a stand with fans that force air through the battery to keep the heat under control.

Anybody could do that with existing battery technology, but there’s a very obvious cost: a much lower energy density, meaning a battery has to be much larger to hold the same amount of charge. StoreDot is compensating by working on technology that allows a much higher charge density, which offsets the lower density of materials. In the end, the battery should hold similar amounts of charge per volume as existing batteries, despite having less battery material present.

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What happens to the brain on sudden impact? Egg yolks could hold the answer



A rotational deceleration experiment with egg yolk, using an egg scrambler and measuring the soft matter deformation, to find possible answers about concussions.

A growing number of professional football players have been diagnosed with a neurodegenerative disease called chronic traumatic encephalopathy (CTE), likely the result of suffering repeated concussions or similar repetitive brain trauma over the course of their careers. It’s also common in other high-contact sports like boxing, Muay Thai, kickboxing, and ice hockey. We might find clues about the underlying physics by studying the deformation of egg yolks, according to a new paper published in The Physics of Fluids. This in turn could one day lead to better prevention of such trauma.

Egg yolk submerged in liquid egg white encased in a hard shell is an example of what physicists call “soft matter in a liquid environment.” Other examples include the red blood cells that flow through our circulatory systems and our brains, surrounded by cerebrospinal fluid (CBR) inside a hard skull.  How much a type of soft matter deforms in response to external impacts is a key feature, according to Villanova University physicist Qianhong Wu and his co-authors on this latest study. They point to red blood cells as an example. It’s the ability of red blood cells to change shape under stress (“erythrocyte deformability”) that lets them squeeze through tiny capillaries, for instance, and also triggers the spleen to remove red blood cells whose size, shape, and overall deformability have been too greatly altered.

In the case of traumatic brain injury, it is linked to how much the brain deforms in response to impact. The precise cause of CTE is still a matter of ongoing research, but the prevailing theory holds that repetitive brain trauma can damage blood vessels in the brain, causing inflammation and the growth of clumps of a protein called Tau. Eventually those clumps spread throughout the brain killing off brain cells. Those suffering from CTE often experience memory loss, depression, and in severe cases, dementia, among other symptoms.

Prior studies have shown that deformation of soft matter in a liquid environment occurs in response to sudden changes in the fluid field, such as shear flow or a sudden change of the flow pathway. Wu et al. were interested in the specific case of soft matter in a liquid environment that is also enclosed in a rigid container—like the yolk of an egg, surrounded by liquid egg white, all encased in a shell. They wondered if it was possible to break the yolk without breaking the shell, since it’s the case with most concussions that the brain can be damaged without cracking the skull.

To answer that question, Wu et al. set up a simple preliminary experiment with a Golden Goose Egg Scrambler, a novel kitchen device that enables users to scramble an egg right in the shell. Wu’s team applied rotational forces to scramble the egg and were intrigued by how the egg yolk deformed and broke while the shell remained intact. That inspired them to conduct additional experiments to glean insight into the fundamental flow physics behind the effect.

They purchased fresh eggs from a local grocery store, removed the yolks and egg whites, and then placed them in a transparent rigid container, the better to monitor the deformation by recording the entire process with high-speed cameras. They built two separate apparatus. One administered so-called “translational impact”—i.e., striking the container directly—via a small hammer falling from a vertical guide rail (see Fig 1A in gallery), with a spring at the bottom enabling the container to move vertically. They used an accelerometer to measure the container’s acceleration.

For the second setup (see Fig 1B in gallery), they connected the container to an electric motor to study two types of rotational impact: accelerating rotational impact and decelerating rotational impact (i.e., when the outer contained is speeding up or slowing down as it rotates). They also peeled off the membranes surrounding the fresh yolks and suspended them in petri dishes filled with water, the better to study how those membranes, too, respond to stress.

Wu et al. were somewhat surprised to find that, in the case of translational impact, there was almost no deformation of the yolk. Instead, the entire container (and its contents) moved as a single rigid body. In the case of accelerating rotational impact, the team found that the yolk would start out in a spherical shape and then begin to stretch horizontally to form an ellipsoid. The yolk could maintain a stable ellipsoid shape for several minutes if the angular velocity was kept constant.

The most intriguing results occurred in the case of decelerating rotational impact. Here, the yolk began deforming significantly almost immediately, expanding horizontally and increasing its radius at the center—sufficient deformation to severely damage the yolk under sustained stress.

“We suspect that rotational, especially decelerational rotational, impact is more harmful to brain matter.”

To make sure this wasn’t primarily an effect of the yolk as a biomaterial, Wu et al. conducted the same experiment with synthesized soft capsules submerged in a calcium lactate solution, enclosed by a thin membrane of calcium alginate. They got similar results, confirming that “the dominant mechanism leading to the deformation of soft matter in a liquid environment is a result of mechanical forces instead of biological responses,” they wrote.

Based on this, “We suspect that rotational, especially decelerational rotational, impact is more harmful to brain matter,” said Wu, and that centrifugal force likely plays a critical role. “The large deformation of brain matter during this process induces the stretch of neurons and causes the damage.” This could explain why a boxer can get knocked out by a sharp blow to the chin. “Considering the chin is the farthest point from the neck, hitting on the chin could cause the highest rotational acceleration/deceleration of the head,” the authors concluded.

“Critical thinking, along with simple experiments within the kitchen, led to a series of systematic studies to examine the mechanisms that cause egg yolk deformation,” Wu said of the implications of their findings. “We hope to apply the lessons learned from it to the study of brain biomechanics as well as other physical processes that involve soft capsules in a liquid environment, such as red blood cells.”

DOI: Physics of Fluids, 2021. 10.1063/5.0035314  (About DOIs).

Listing image by Ji Lang/Qianhong Wu

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