engine temperatures

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Sterling Engine: low temperature difference engine turns a fraction of the heat of hot tap water into mechanical motion. For this engine the heat source is the hot tap water, and the heat sink is the room temperature air. Really nice model and super inexpensive for a display engine of this type

  • Jim is very sensual, sure. He’s very into sex, and when he’s at it, a very dedicated lover. He’s also just very lucky with Bones, who keeps him very interested, and who’s just equally into him. But sometimes, work is stressful enough that even sex can’t keep him distracted long enough. “Jim,” Leonard says, voice coming out a little like a moan, though not all that pleased. “Jim,” Leonard urges, and Jim tears his gaze away from the ceiling. His hands move up to Leonard’s hips, throwing him a small smile. Leonard’s hands are on Jim’s chest, and the messy hair and slight flush on Leonard’s cheeks looks absolutely stunning, but the annoyed look on his face isn’t as promising. “When you called me over to your quarters for sex, I expected both of us to be there. I’m here, where are you?” Jim sits up straight, sliding his arms around Leonard’s waist. “I’m right here, too.” “Hmm, no,” Leonard says, and Jim realizes he messed up when Leonard slides off of him, “want to talk about it?” “Talking was the opposite of what I wanted,” Jim replies, and Leonard huffs, pulling Jim down with him. “If you didn’t want to talk about it, you would’ve paid more attention to me. Now, talk to me.”
  • Other times, though, Jim’s really into it. Too much so, maybe. Leonard knows just how to move, it drives Jim crazy. Arms and legs both wrapped around Leonard’s body, pulling him impossibly closer. And Jim’s close, so close; moans shamelessly loud. In excitement, he rolls them around to straddle Leonard’s hips instead, but he rolls just a little too far, a little too quick, and it just rolls them right off bed. They’re on the ground in a mess of tangled limbs and bed sheets, and Leonard groans in discomfort. “Damn it, Jim,” he cusses at him, but then laughs, and Jim does, too.
  • Jim’s lips are all over Leonard’s body. His chest, his thighs, his neck, his stomach. Even though they’ve only been separated a weekend or so, Jim’s clearly missed the other more than he anticipated. Leonard’s enjoying it, too, judging by the sounds he’s making, and the way nails drag over Jim’s naked back. “Captain Kirk, report to Bridge,” Spock’s voice rings over the intercom, and Jim visibly tenses, briefly, then leans down to kiss Leonard anyway. “Kirk to Bridge,” Spock urges, and Jim pushes himself off his boyfriend with a grunt. “What?” he snaps at the intercom after turning it on. “There’s a non-responsive vehicle heading towards us, Captain,” Spock says, with a hint of annoyance in his voice for being snapped at, “it requires your immediate attention.” Jim sighs, gritting out a quick: “understood”, and then he grabs his shirt off the floor. “Don’t stay up for me,” he tells Bones, fully knowing that the other will just follow him out to the Bridge, anyway.
  • Sex just hasn’t been happening for a while, and Jim’s getting a little antsy. Things get in the way, one of them’s already asleep when the other returns from their shift, or life in general just gets in the way. And then the night they do have off together, one of the engines responsible for the temperature regulation breaks down, and the entire Enterprise is warm. Too warm to fall asleep in, let alone get frisky. So Bones suggests a cool shower, which Jim readily accepts. Brilliant idea, in theory, until Jim slips over his own shower gel and hurts his tailbone, and that sets them back a couple days, too.
  • Luckily, though, sometimes it does happen when they least expect it. They’ve been bickering all day, Bones is visibly annoyed, Jim is no better. They don’t even sleep in the same bed so both of them think about their argument most of the night. Jim’s exhausted the next morning, still a little annoyed. And yet, there’s something about Bones coming into the conference room that morning. Disheveled hair, tired eyes, slight scruff on his cheeks. Jim wants to be mad, wants to scold the other publicly for his remarks the day before, hoping Spock would jump to his defense. But instead, Jim remains quiet, appreciating the look - and hating himself for doing so. Bones knows, though, and it looks like he’s no better. So after the morning meeting is over, and Jim gets up to leave, hands find his hips and Jim gets pressed against the wall; lips chasing his own. And as Bones’ hands tug at Jim’s pants, he knows he’s about to become a lot more acquainted with the desk in this stupid little office.
  • “Why don’t we sleep together every night anymore?” Jim asks out loud, before he even knows he does. Bones is just reading the news on his PADD. Probably sending Joanna a few messages, too, and he turns to look at Jim with a frown. “Do you want that?” “Well yes, obviously.” “I guess shifts are making it hard to do that, sometimes,” Bones says, putting his PADD away and instead he focuses on Jim. “I can reschedule your shifts to match mine,” Jim says, turning to lie on his side instead, sliding an arm around the other’s waist. “You’re not going to mess up the medbay shifts just so you can get laid,” Bones warns him, and Jim laughs. “Fine.” “Besides,” Bones continues, “sometimes it’s nice just to lie here and talk. Even though you say a lot of dumb shit, I like listening to you.” “Hmm,” Jim agrees, fingers gently running over Bones’ cheek, “I like listening to you, too,” he admits, “talking the night away about your medical things, I can listen to that all night.” “Good,” Bones says, and Jim grins. “Especially if I get to bang you after.”
Thermodynamics

Heat capacity

See previous posts about thermal physics

Heat capacity c is a measure of the amount of thermal energy Q can be put into a system before we see a change in its temperature ΔT. It is defined by the equation

where ΔT may be defined as ΔT = T - T0 for an initial temperature T0 and a final temperature T, so

Therefore, if you put 5 J of energy into some volume of liquid, we’ll call it X, which is at an initial temperature T0 = 20°C and observed its temperature change to T = 25°C then it would have a heat capacity cX

Specific heat capacity

This is particularly useful for engineering purposes because a heat capacity can be used to characterise gases and materials etc. For example, the specific heat capacity c of a material is found using its heat capacity per unit mass:

(note that this equation assumes that the heat capacity is independent of mass – i.e. for no phase transitions).

CS/Snook fic: Driven Snow

Summary: Killian Jones wants to learn how to drive and enlists Snow to teach him, but they hit a speed bump or two along the way.

Word Count: ~5200

Rating: PG/K

Links: AO3

Notes: Thanks to @epiplectic-bicycle for the beta and @wingedlioness and @phiralovesloki for the extra eyeballs. ETA: @duathadun made a great header for this! Thanks so much! I love it!


Killian watched Emma yawn for the second time as she reached the archway of Granny’s patio, the first having erupted when she stepped out of the door of the diner into the night. She had circles under her eyes, and her gait was far slower than usual, even if “usual” was running into whatever danger Storybrooke and its citizens found themselves in.

She and David were catching up about their work schedule over the next couple of days, and Killian hung behind, walking with Snow, who was holding her sleeping son in her arms. As Emma reached her car, she glanced at Killian with a small tip of her head toward the passenger side, barely stifling yawn number three.

He raised his finger to signal he needed a moment. As David took the baby from Snow to finagle the child into his car seat, Killian reached over and placed his hand on Snow’s arm, stopping her.

“A word, Snow?”

“Uh, sure, Killian. What is it?”

Snow glanced over at David’s progress then back at Killian and smiled.

“I was wondering if I may ask a favor of you.”

“Of course, anything,” she said.

He nodded toward the street where the cars sat idling. “Would you have time to teach me how to pilot one these vessels?”

Snow looked happily surprised. “Driving lessons?”

“Aye.”

Smiling brightly, she said, “I think I can squeeze that in.”

“I’m much obliged.”

A puzzled look passed over Snow’s face as she considered Killian. “Mind if I ask something?”

“Of course not,” he said.

“Why not Emma? Or David?”

“Emma’s busy enough. I don’t need to be under foot all the time. And I’ve seen what happens when David teaches someone to drive. I’d rather not cause any more damage to his truck. Or the town.”

Snow laughed. “His truck is becoming a bit of an eyesore. And I’m not sure the city budget can take another hit either. Do you want to start tomorrow? How about 10am?”

“Perfect. I’ll see you then.” Killian bowed. “Thank you, m’lady.”

Keep reading

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     The Pratt & Whitney J58 engine, coupled with the world’s most complex air inlet system, propelled the Blackbird aircraft seamlessly through an enormous range of speeds. Originally, she was a Navy project designed to power the Martin P6M SeaMaster flying boat. She would eventually be painstakingly adapted to work at Mach 3+ flight and see operation in something very different than a seaplane.

     The Blackbird aircraft is constructed of over 90% titanium. The engines, however, used materials which could withstand even higher temperatures. Pratt & Whitney turned to exotic nickel and cobalt-based alloys, like Inconel X (which was also be used in the skin of the X-15 rocket plane, Mercury Spacecraft and Apollo F-1 Engine combustion chamber), with some of these materials experiencing operating temperatures of 1,600 °F. Fluid lines were plated with gold or silver. The exhaust ejector was coated with a thermal insulating ceramic which would reach 3,200 °F, undergoing so much heat and pressure that it would never char.

     When the J58 fires its afterburner, the whole aft end of the engine glows orange like molten lava. These materials allowed the J58 to operate in afterburner indefinitely, which was required for Mach 3+ cruise. Most aircraft can not continuously operate the afterburner for more than a few minutes at a time without suffering a catastrophic failure.

     During development, engineers searched high and low to find a lubricant that could operate under such a wide range of temperatures. Finally, a silicone-based grease was found, which had the consistency of thick peanut butter at room temperature. Before engine start, this grease was preheated to further liquify it. For engine start, the J58 required the assistance of two Buick V-8 or Chevy Big Block housed in a start cart on the ground.

     When the Blackbird cruised at Mach 3+, the compression of the air would cause incredible heating over the entire aircraft. The fuel inside the tanks would reach 350 °F. Normal JP-4 fuel would foam and possibly combust at these temperatures, so a special JP-7 fuel was developed with a special high flash point. Because of this high flash point, the J58 had a unique starting method. When the start cart had the engine spinning, a shot of Triethylborane (TEB) was injected into the combustion chamber. When TEB touches air, it explodes, which would cause the fuel in the engine to ignite, initiating engine start. Every time the pilot moved the throttle forward from idle, a shot of TEB was introduced into the combustion chamber. Additionally, every time the throttle was moved forward from full military power, teb was fired into the exhaust section of the engine to ignite the afterburner. 

     One of the most amazing parts of this engine is its compressor bypass system. When the aircraft flies at more than Mach 2.2, a series of large bypass tubes allow air from the inlet to bypass the compressor section, feeding it straight into the afterburner section, creating the majority of the engine’s thrust. However, this is not a true ramjet because even with these bypass tubes operate, air still flows through the compressor and combustion sections in a traditional manor. With these two concepts working together, we call the J58 a Turboramjet.

     The J58 could not do its job without an incredible inlet system. A supersonic shock wave builds up on the tip of the iconic cone that protrudes from the inlet. We call this cone a ‘spike’. Once air enters the inlet, it is forced into a system of shockwaves, diffusing the supersonic air, slowing the air to subsonic speed. This process creates a huge increase in air pressure, which can be fed into the engine, increasing its power and efficiency. This process is called pressure recovery. At Mach 1.6, the system of shockwaves inside the engine is optimized for maximum pressure recovery. When the aircraft accelerates faster than Mach 1.6, the spike has to retract into the inlet to properly shape balance the shockwaves to continue optimal pressure recovery through a range of speeds. The spike retracts 1.6’’ for each additional 0.1 Mach, and is retracted a total of 26’’ at full speed, Mach 3.2.

     Thanks to the wonderful Frontiers of Flight Museum in Dallas, Texas for allowing visitors to get up close and personal with this J58.
Getting to Mars: What It’ll Take

Join us as we take a closer look at the next steps in our journey to the Red Planet:

The journey to Mars crosses three thresholds, each with increasing challenges as humans move farther from Earth. We’re managing these challenges by developing and demonstrating capabilities in incremental steps:

Earth Reliant

Earth Reliant exploration is focused on research aboard the International Space Station. From this world-class microgravity laboratory, we are testing technologies and advancing human health and performance research that will enable deep space, long duration missions.

On the space station, we are advancing human health and behavioral research for Mars-class missions. We are pushing the state-of-the-art life support systems, printing 3-D parts and analyzing material handling techniques.

Proving Ground

In the Proving Ground, we will learn to conduct complex operations in a deep space environment that allows crews to return to Earth in a matter of days. Primarily operating in cislunar space (the volume of space around the moon). We will advance and validate the capabilities required for humans to live and work at distances much farther away from our home planet…such as at Mars.

Earth Independent

Earth Independent activities build on what we learn on the space station and in deep space to enable human missions to the Mars vicinity, possibly to low-Mars orbit or one of the Martian moons, and eventually the Martian surface. Future Mars missions will represent a collaborative effort between us and our partners.

Did you know….that through our robotic missions, we have already been on and around Mars for 40 years! Taking nearly every opportunity to send orbiters, landers and rovers with increasingly complex experiments and sensing systems. These orbiters and rovers have returned vital data about the Martian environment, helping us understand what challenges we may face and resources we may encounter.

Through the Asteroid Redirect Mission (ARM), we will demonstrate an advanced solar electric propulsion capability that will be a critical component of our journey to Mars. ARM will also provide an unprecedented opportunity for us to validate new spacewalk and sample handling techniques as astronauts investigate several tons of an asteroid boulder.

Living and working in space require accepting risks – and the journey to Mars is worth the risks. A new and powerful space transportation system is key to the journey, but we will also need to learn new ways of operating in space.

We Need You!

In the future, Mars will need all kinds of explorers, farmers, surveyors, teachers…but most of all YOU! As we overcome the challenges associated with traveling to deep space, we will still need the next generation of explorers to join us on this journey. Come with us on the journey to Mars as we explore with robots and send humans there one day.

Join us as we go behind-the-scenes:

We’re offering a behind-the-scenes look Thursday, Aug. 18 at our journey to Mars. Join us for the following events:

Journey to Mars Televised Event at 9:30 a.m. EDT
Join in as we host a conversation about the numerous efforts enabling exploration of the Red Planet. Use #askNASA to ask your questions! Tune in HERE.

Facebook Live at 1:30 p.m. EDT
Join in as we showcase the work and exhibits at our Michoud Assembly Facility. Participate HERE.

Hot Fire Test of an RS-25 Engine at 6 p.m. EDT
The 7.5-minute test is part of a series of tests designed to put the upgraded former space shuttle engines through the rigorous temperature and pressure conditions they will experience during a launch. Watch HERE.  

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com