The paper you reference is a year old, criticizing an earlier paper. The recent publication describes recent tests which directly address most of those criticisms,
k2backhoe (1092067) writes "I have bought heavily from Amazon Prime for nearly 2 years. Is it just me, or do other
/. folks notice delivery slowing down? First I noticed increasing use of USPS to do the final delivery, frequently 1 day later than the "Guaranteed delivery" date. Originally if I complained, I got a small credit to my account, now complaints get no response. Then (because I keep page copies of all my orders) I noticed that even though the "Review your order" page said "Guaranteed", the page listing a history of your orders sometimes shows "Delivery estimate" while other orders still say "Guaranteed delivery by:" And now I see them suggesting "Get a $1 credit toward your next book or ebook purchase when you choose FREE No-Rush Shipping" to NOT ask for the free 2 day delivery. All this with raising the price of Prime by 25% makes me want to ask if others are noticing this, or have an explanation (besides cutting shipping costs)."
Good article with some believable numbers. But when transmitting 100 kW at 85% efficiency, you have to wonder what is happening to 15 kW of magnetic field. Where is it going, who is it affecting? Will my fillings heat up, or my cochlear implant overload if I am near by?
This has 512 m^2 solar array, incoming sun at directly overhead is roughly 1 kW / m^2, assume solar panel efficiency of 15%. This is a total power of about 76 kW or about 100 HP when the sun is directly overhead. Averaged over a 24 hour day, this is maybe 20-25 HP. 89,000 kg of lithium battery at 200 Wh / kg is 17.8 MWh. This would take 234 hours to charge with the sun directly overhead. That is about 40 days of clear sky charging, assuming you are not running the propeller at the same time. Something is fishy here. Sounds like he charges in port, then runs to the next port on solar plus battery (otherwise there is no need for this large battery / solar cell ratio). Then he repeats. Is my math wrong, or is this story a bit strange?
SternisheFan points out that there is a great new panorama made from shots from the Curiosity Rover. "Sweep your gaze around Gale Crater on Mars, where NASA's Curiosity rover is currently exploring, with this 4-billion-pixel panorama stitched together from 295 images. ...The entire image stretches 90,000 by 45,000 pixels and uses pictures taken by the rover's two MastCams. The best way to enjoy it is to go into fullscreen mode and slowly soak up the scenery — from the distant high edges of the crater to the enormous and looming Mount Sharp, the rover's eventual destination."
yyzmcleod writes "Building on the work of last year's bionic creation, the Smart Bird, Festo announced that it will literally launch its latest creation, the BionicOpter, at Hannover Messe in April. With a wingspan of 63 cm and weighing in at 175 grams, the robotic dragonfly mimics all forms of flight as its natural counterpart, including hover, glide and maneuvering in all directions. This is made possible, the company says, by the BionicOpter's ability to move each of its four wings independently, as well as control their amplitude, frequency and angle of attack. Including its actuated head and body, the robot exhibits 13 degrees of freedom, which allows it to rapidly accelerate, decelerate, turn and fly backwards."
Loved the Journeys series
With rockets, faster acceleration means LESS total fuel to orbit, not more (assuming you can just use the same fuel either faster or more slowly). The shorter time you are fighting the 1G, the less total fuel you use up. Imagine takeoff to orbit at 1.01G (1G earth,
.01G motion). instead of 2G. You take forever to achieve orbit and the first 1G is wasted all that time.
The only advantage I see is (as you say) lighter engines and structure. Still seems low compared to any other rocket I have ever seen.
In the video it seemed to take 60 seconds to reach 225 m/s, or around 3.5 m/s/s. That's only 1/3 G!! Did the takeoff seem slow to others? Even manned rockets accelerate a lot faster than that! What's wrong with my analysis or their rocket?
Used for navigation. Provide wrong navigation coordinates to the pilots under conditions of reduced visibility. The humans will follow blindly in most cases. We have seen large numbers of aviation accidents like this. Remember the plane that got shot down over NK because the pilot had entered wrong co-ords into the autopilot? Sorry for your anger and lack of imagination. I just hope the terrorists have similar mind sets.
Cyber war gave us the stuxnet worm that was very selective and only activated when it could ruin gas centrifuges. The Ipad would make airlines vulnerable to a clever al qaeda hacker who makes a worm that activates when certain critical conditions were met (i.e. when a US airliner was over water, or during a critical landing maneuver). Are we conceited enough to think that USA and Israel are the only ones with master hackers?
Valid point. some sections of usrr can override the operator,but it is very expensive.
If you pay attention to the accidents, you will see the train accidents are almost always due to human error, not signaling equipment failure. Drivers going thru flashing red signals, engineers under the influence or texting, and occasional sabotage. Signal equipment almost always fails safe. This causes very annoying (but safe) delays while the equipment is fixed.
I worked on US rail signaling equipment (Background = Physics PhD). I have never been so impressed with over-designed, fail-safe equipment. They plan for everything, including multiple lightning strikes. They do such things as positioning their relays upside down so that the armature falls to NC by gravity if the spring breaks. They have many years of experience, and all of our equipment is for sale. I think the NIH mentality bit China in the arse this time.
If your premise is that the dynamics of software is faster than other technologies, then this only makes sense if you can streamline the patent examination process to grant software patents in an average of 6-9 months. This also implies publishing the applications after only 2 months, and acting on public input in a month or less. An interesting idea, but not feasible with the current USPTO.