As they carried Tiona’s stuff up to her room Lisanne said, “What’s new in your life?”
Tiona laughed, “Well, my research is crap! I’ve made exactly zero progress on finding the superconductor our theory predicts.”
Lisanne smiled, “Well, if physics was easy, everybody’d be doing it.”
Tiona gave a horrified look, “Would not! They’d still think it was boring!”
Lisanne grinned, “Well then, what about your love life?”
Tiona grimaced, “Ronnie’s got a new band and so far they’re doing pretty well, but I’m not seeing him very much.”
“Any other prospects?”
Knowing that her mother thought Ronnie was a terrible choice; Tiona grinned at her and winked, “All the other guys are boooooring.” She turned toward the door and cupped a hand to her ear, “And I think I hear Dad coming up to rescue me from this conversation.”
“You don’t have to hold a hand to your ear,” Lisanne laughed. “He’s coming up the stairs so fast the whole house is shaking.”
They heard the door to Vaz’s basement lab open and Vaz shouted, “Tiona!”
Tiona and Lisanne both looked at each other for a moment in surprise. Vaz was rarely demonstrative and neither one of them would have been surprised if he’d just stayed in the lab and waited for Tiona to come down, rather than coming up himself. Tiona called out, “I’m up in my room Dad.”
“Come down to the lab!” Vaz called excitedly. “You’ve got to see this!”
Tiona and Lisanne looked at each other again and Lisanne rolled her eyes. Of course Vaz wasn’t excited to see his daughter. He wanted to show her some experiment! Tiona said, “I guess I better get down there before he comes and drags me down there.”
Down in Vaz’s basement lab, Tiona saw an almost exact replication of her own experimental set up. She recognized her current generator, wiring, electrodes, and etcetera. The glass dish that she had had her membranes lying in was notably absent. Instead, she saw what looked like a plastic disc lying there with the electrodes attached to it. Surprisingly, instead of the electrodes being attached on opposite sides of the disc, they were attached one next to the other.
Vaz excitedly pointed out the features. “Instead of just laying the membranes in a dish, I’ve attached them to both sides of this acrylic disc with spray adhesive.”
Tiona frowned, “But with the acrylic disc between the two membranes there won’t be any conduction.”
“Ah, yes, that’s true. But I’m not interested in conduction like you are. I’m interested in the movements your membranes make!”
“How can they wiggle when they’re glued to a rigid disk like that?”
“Watch this!” Vaz switched on the power. The acrylic disc immediately flipped up into the air, trailing the wires attached to the electrodes. The drag of the electrodes flipped the disc over and it immediately shot down and hit the desk.
To Tiona’s astonishment, it then appeared to be trying to burrow into the desk! “Wha…!” Tiona trailed off, staring at the disc in consternation. “How can that happen?!” She stepped near to the lab bench and started looking at the disc from all angles. Absently she reached over and switched off the power. The disc immediately relaxed from where it had been bowing itself as it tried to push itself down against the desk but was held up on one edge by the electrode. She turned to look at her father questioningly.
“Amazing, huh?”
“But how does it do that?!”
Vaz shrugged and rubbed his hands together excitedly, “I don’t know! We’ve got to find out!”
For a fleeting moment, Tiona thought longingly of her plans to hang out with her friends. Then she looked back at the disc that lay in all apparent innocence on the desk attached to the wires and her curiosity took over. “Are you running the same current that I was?”
“Well, yes. But when I measured the current the generator in your lab was putting out, my meters showed that it wasn’t putting out the balanced sine wave that its settings would have indicated. The current had a large bias. So I’m running the current that you were, though I’m not running the current you thought you were!” He looked extraordinarily pleased.
Tiona blinked, “Does the disc still move if there’s no bias?”
Vaz grinned, “No!” he exclaimed.
“So you’re saying,” Tiona said slowly, “that not only were my electrodes screwed up because somebody had insulated one side of them, but my current generator was faulty and producing a biased current?!”
Vaz slowly nodded a huge smile on his face.
Irritated, Tiona continued “So all the measurements I’ve been making and carefully recording are probably wrong and need to be repeated!”
Vaz looked disappointed, “Serendipity Tiona! Serendipity!”
“That’s not serendipity! It’s a monumental screw-up, and a lot of work that I’ll have to repeat!”
“Who cares about superconductors Tiona?! Feel this!” He picked up the disc, turned it over and held it out to her.
When she took it, he flipped on the power. At first she jerked back at the thought that she might get shocked by the current, instead she was stunned when the disc started pushing up into the air. It pushed hard enough that it slipped out of her grip and flailed around on the end of the wires until her dad turned off the power. She frowned again, “How is it doing that?!”
“That’s the question! And it’s a much more important question than whether you can make a superconductor that’s based on graphene. How is it moving? There isn’t a magnetic or electrical field for it to react to. It shouldn’t flop around like that!”
Father and daughter stared at one another for a moment; then turned to look back at the innocent looking clear plastic disc.
***
Tiona did go out with a couple of her friends that night, but the next morning she found herself lying awake thinking about the membranes and trying to understand how they could possibly do what they were doing. Her dad had spent the rest of the afternoon yesterday showing her what he had learned about the membranes’ unusual properties so far.
It required at least two membranes that were somewhat parallel to one another, overlapping, and energized on different limbs of the circuit. The circuit had to deliver a biased alternating current in the gigahertz frequency range. Separating the two membranes a little bit to put them on each side of the acrylic disc had resulted in an increase in the force produced.
Tiona heard someone moving around downstairs in the kitchen, so she got up, stepped into her shoes, and walked downstairs hoping that they’d already made coffee. Her dad was in the kitchen with a frying pan on the stove. “Hi! Want a breakfast burrito?”
Tiona nodded. “Is there any coffee?”
“I don’t drink coffee.” He turned and looked at the coffee maker. “But your mother set up the coffee maker last night. I think all you have to do is turn it on. It comes on by itself at seven.”
Tiona flipped on the coffee maker then turned to watch her father. “Can I do anything to help?”
Vaz looked at his ingredients where they were laid out and pursed his lips. “I don’t think you should. Whenever anyone tries to help me cook… it turns out awful.”
Tiona said, “Well that breaks my heart. I guess I’ll just have to sit here and watch you make my breakfast then.”
Soon Vaz had scrambled eggs with chopped ham, onions, olives and salsa. He spooned this on to tortillas hot from the microwave, sprinkled on cheese, rolled them up and put a couple of them on a plate for Tiona. She poured herself some coffee and they sat down to eat.
Vaz said, “So, there are lots of things we need to find out.”
“About the membranes?”
He blinked at her as if wondering what else she could possibly think he was talking about. “Yes.” After a moment in which Tiona said nothing, he continued, “We need to know whether it works with some of your other membrane doping schemes or only with the copper and lithium doping.
You already told me that if they aren’t doped they don’t move, but is it any doping scheme? Is there a doping scheme that works better?” He paused again as if waiting to see if Tiona had any comments about that; then continued. “They work better if separated by that thin acrylic disc. Is it just the fact that the disc provides an insulator and any kind of thin insulating disk works, or does it need to be acrylic? Does it work better if they are closer together, or farther apart?”
Tiona said, “Let me make a list.” She looked up at her HUD; then started murmuring to her AI. After a minute she turned her gaze back to her father. “If it still works when they’re separated, we can try to insert probes and see if a field is being generated between the two membranes.”
“Yeah, add that to your list. We should also find out what happens to our efficiency if we make the membranes bigger or smaller.”
Tiona grinned at him, “We’ll need a set up to be able to precipitate bigger or smaller ones. Multilayer graphene is pretty hard to cut.”
“Can you precipitate some more membranes here in my lab, or will you have to go back to Chapel Hill?”
Tiona shrugged, “It depends on what kind of stuff you have in stock.”
They made a few more lists then headed downstairs to the basement to start trying to figure out what they had and what they would need to order. Once they’d placed their orders, they started trying to figure out what experiments they could do with the equipment that they already had on hand. The first and most obvious thing was for Tiona to drive to Chapel Hill and pick up all the different doped membranes she had made so far. Then they could see which of those were effective and if any particular doping scheme was much better than the others.
When Tiona returned with the folders full of membranes, her father turned to her with an excited look. “I peeled one of the membranes off of the acrylic disc and mounted it on another acrylic disc.”
Tiona laughed at herself when he said this because her initial reaction had been that he could have ripped the thin membrane trying to pull it off. But graphene was the strongest material known to man. He would have been much more likely to break the acrylic disc if the adhesive was strong enough. To her dad, she said, “What did you find with that?”
“I put the first one on top of the digital scale; then stacked paper on top of it then put the second one on. I get the most force for a given current when they’re about a centimeter apart. I’ve tried it with a centimeter thick sheet of acrylic and a centimeter thick sheet of aluminum between the membranes and I get exactly the same force so it doesn’t seem to depend on the kind of material that’s between them.”
Tiona said, “I’m going back up to my car. I brought some chemicals, copper sheeting, and other stuff to let us precipitate bigger and smaller discs. We can replace what we use that came from UNC out of the supplies we’ve ordered when they come in. I’ll just take it back when I go back to school in January.”
Vaz said, “We should try other shapes of membranes too. I can’t imagine why the effect would depend on shape, but we need to know for sure.”
Tiona frowned, “It seems to me that we should start by figuring out which dopants make the best membranes for… ‘the effect?’” She looked up at her dad, “We need a name for this effect.”
Vaz gave a sly grin and ducked his head as if a little embarrassed, “The Gettnor effect?”
Tiona snorted, “That would be the ultimate arrogance. We can’t name it Gettnor ourselves. It’d be okay if somebody else named it after us, but even I’d hate us if we named it after ourselves.”
“Let’s call it ‘thrust’ then. That’s what it is.”
“Thrust?” Tiona thought about it. The discs were pushing somewhere through space, so they were indeed generating thrust. She snorted, “You’re right. It’s thrust. I don’t know why I thought we had to have a fancy name for it.”
***
By the end of the afternoon, they had tested sample membranes of all of the different doping schemes that Tiona had tried so far. Though several of them produced faint thrust, only the lithium-copper membranes yielded significant force.
When Tiona got down to the lab the next morning, Vaz had set up precipitation stations on several of his benches. A very large dish was set up to precipitate lithium-copper doped graphene. He’d cut out copper templates for big discs and small discs, as well as several different shapes including squares, triangles and long slender rectangles. Two other stations were set up to precipitate doping combinations that Vaz thought might work, but that Tiona hadn’t tried since she didn’t expect they would make good superconductors. There was even one station that Vaz hadn’t planned anything for in the hopes that Tiona would have a suggestion for it.
Tiona didn’t have an idea at first, but by the time they had the other stations going Tiona suggested they try lithium-copper-titanium and they worked to set that up as well.
Once the precipitation was underway, Tiona stood up and stretched. “Well, there’s nothing to do until these new membranes are done. I’m ready for a day of vacation, how about you?”
Vaz looked at her, uneasily shifting from one foot to the other. After a moment, he hesitantly said, “I don’t have anything else to do. I’ll see if I can think of any other testing I could be doing while we’re waiting for the precipitations.”
Tiona laughed, “I’ve been having fun working with you. But, seriously, I’m going to go try to think of something else we could do that doesn’t involve science. How about a movie?”
“Um, on the big screen in the living room?” he asked, sounding a little apprehensive.
“No!” Tiona laughed again, “I’m trying to get you out of the house to do something different. Something social! We need to go to a theater.”
Vaz looked very uncomfortable, “Could we go to an afternoon matinee so it won’t be too crowded?”
Why do I feel like I’m the grownup? Tiona wondered. Aloud, she said, “Sure. I’ll go see what’s on.”
***
The next morning, Tiona was stretching and thinking about getting out of bed when a gentle knock came on the door. “Yes?” she called.
The door creaked open and her mother stepped in. She walked over and sat down on the edge of Tiona’s bed. She said, “Feel like getting up?”
Tiona stretched again, “Thinking about it. Why? Is there a big rush?”
Lisanne grinned, “Your dad’s downstairs about to strip a gear. He won’t start on whatever big project you guys have been working on without you, but I swear he’s getting so anxious to do it that he looks like his head might explode at any moment. He’s made me coffee. He’s mixed up a batch of waffle mix, then been thinking up other little breakfast treats until we’re looking at a full size gourmet brunch down there. I don’t know what he’s going to make next if you don’t come down pretty soon!”
Tiona laughed, “Well, I guess I better get down there then, before we start having to invite the neighbors in to help us eat everything. Tell him to pour me a waffle. I’ll be down in five minutes.”
Lisanne stood back up, “You’re going to have to tell me how you managed to get him to go out to a movie and to dinner with us yesterday.” She winked, “You’re really improving our social life.”
Tiona got out of bed. “It takes a lot of serendipity,” she said mysteriously.
Vaz really had outdone himself with the breakfast. Tiona had a waffle with pecans and whipped cream, a couple of slices of crispy bacon, a small cup of fruit, and a large mug of hot chocolate. She reflected that it was a good thing she liked to run.
Vaz was finished eating long before she was. He sat on the edge of his seat, waiting to go downstairs. Tiona finally relented and said, “Do you want to go down and see what happened with our precipitations Dad?”
If Vaz had been a dog, his tail would have been thumping.
Tiona said, “Let’s clean up the kitchen so we can head on down.”
Lisanne laughed, “Don’t tease your father like that. I
’ll clean up the kitchen; you guys go down and play in the basement.”
After a couple of hours of testing, Tiona and Vaz found themselves sitting and staring at their results. The lithium-copper-titanium disc had generated barely measurable thrust. The same was true for the two membranes Vaz had set up, pure copper doping and lithium-iron. On Tiona’s suggestion they had tried measuring force generation with pairs of discs that had nonmatching doping schemes, for instance, lithium-copper on top and lithium-yttrium on the bottom. The nonmatching schemes really hadn’t worked either, although a few had generated barely measurable force.
The small 2.5 centimeter discs had generated some force, though not much. Vaz had had the idea to try it with less than a one centimeter space between the membranes. The small discs generated more force with 2-3 millimeters between the membranes than they did at the one centimeter distance which had proved to be best for their standard 15 centimeter discs. Still, even with the distance between the membranes optimized, the force generated by the discs wasn’t linear to their area. The 15 centimeter discs had 36 times the area of the 2.5 centimeter discs but generated 42 times the force. Vaz’s large 30 centimeter discs had four times the area of the fifteen centimeter discs, worked best with 1.2 centimeters between them and generated 4.5 times the thrust.
Studying the numbers, Tiona said, “If we assume that the outer edge of the membrane discs don’t generate thrust, then it becomes much more linear to the area of the central portion.”
Vaz grunted. “But how are they generating thrust?”
Tiona shrugged.
Vaz said, “If you look at the power consumption numbers, you can see that the discs are using enough power to generate the thrust. I mean, they’re using more power than they’re turning into heat through resistance to current flow. The excess power is about the right amount to generate the thrust we’re measuring.” He turned to look at his daughter, “But, how is it generating thrust?!” He held up a finger, “The disc is not reacting to a magnetic field.” He held up another finger, “It isn’t reacting to an electrostatic field.” He held up a third finger, “It weighs the same before and after so it isn’t expelling matter to generate thrust according to Newton’s second and third laws. No equal and opposite reaction, eh?” He lifted one more finger, “It isn’t moving matter around itself like a propeller does or we’d feel the air blowing out the back side!”
Tiona_a sequel to Vaz Page 9
