A turboprop engine (Fig. 9.27a) consists of a diffuser, compressor, combustor, turbine, and nozzle. The turbine drives a propeller as well as the compressor. Air enters the diffuser with a volumetric flow rate of 83.7 m3 /s at 40 kPa, 240 K, and a velocity of 180 m/s, and decelerates essentially to zero velocity. The compressor pressure ratio is 10 and the compressor has an isentropic efficiency of 85%. The turbine inlet temperature is 1140 K, and its isentropic efficiency is 85%. The turbine exit pressure is 50 kPa. Combustion occurs at constant pressure. Flow through the diffuser and nozzle is isentropic. Using an air-standard analysis, determine (a) the power delivered to the propeller, in MW. (b) the velocity at the nozzle exit, in m/s. Neglect kinetic energy except at the diffuser inlet and the nozzle exit.
Psychology Week 10 Notes Cultural Differences in Emotion - Experiment with emotional faces (Ekman & Friesen) o Hypothesis: Emotions are learned through social interactions & they should vary across cultures. o Results: They were wrong, all faces were the same emotions, st was it because they were all 1 world countries o Experiment 2, same hypothesis but use people from New Guinea, and the faces were the same o Therefore, “Eckmans Faces” results show us emotional faces are biological. Biological Behavior (Emotion) - Amy Cuddy studied body language and hand signals (no words) - She sees that even animals have the same expressions in body language by expanding when their dominant & intimidating while shrinking when intimidated or scared. - She also noticed that runners who were blind (aka hadn’t observed other behavior) and won races would throw their hands up and raise their chin after winning (which regular runners do too) to display pride. Culture to Culture - Some things are different, magnitudes of emotion - In the individualistic western countries, there is vibrant and strong emotion being showed compared to the collectivistic eastern countries which show subtle emotions. - These differences are known as Display Rules o Display Rules are how and why emotions happen - Men and women have no differences in experiencing emotions. What do emotions do - Tools for cognitive functioning. There’s no cognitive functioning without emotion. - Affect helps with decision making o Positive Affect: approach Ex) you see a puppy and you want to approach it o Negative Affect: Avoid Ex) you see a poisonous snake coming toward you and you avoid it Emotion and Learning o (Recall that learning is the lasting change in behavior because of an experience.) - If you get a queasy feeling in your stomach on a roller coaster while you’re up high, you use your past events to evaluate feelings this is known as “A gut feeling” which you use your learning and emotion to evaluate. o This is the Somatic Marker Theory: Actions cause experiences to shape our actions. Ex: Heart rate increases, you get goosebumps, or start to feel queasy. It can adapt our behavior Ex) if you get a ticket speeding, you may feel bad the next time you speed which causes you not to speed. - Bechara et. Al 2005 o Studied speeding & tickets by using the “Iowa Gambling Task” where they studied patients with a damaged middle prefrontal cortex because they’re insensitive to somatic markers. o Control group: normal brain, if there was a deck that caused them to lose money they would avoid the deck. o Patients w/ brain damage: keep going back to deck even if they lose money. Affect-as-information Theory - Mood affects decisions 2 o Ex) ask people how they feel on sunny & rainy days. There was a significant difference in how they felt. o Ex) ask people how they feel on sunny & rainy days and inform them that the weather may affect their answer. There was no longer a significant difference. - Emotions reduce future errors o Ex) Guilt after cheating - Researchers looked at emotions of Olympians who placed. They noticed the Bronze winner was happier than Silver. o This is due to counterfactuals Counterfactuals - 2 types o Upward counterfactual: Imagining a better possible outcome Ex) Stepping over the 3 point line in basketball when you make a shot and thinking “I could’ve gotten 3 points for that shot instead of 2” o Downward counterfactual: Imagining a worse possible outcome Ex) Making the same shot and thinking “at least I didn’t air ball” Emotions & Decisions - Emotions help with decision making and increase or decrease the behavior frequency. - When emotions are extreme, they can lead to irrational, self-defeating behaviors. Emotion & Motivation - Emotions are triggers for us to change. - Serve to signal that something is wrong (for the majority anyways) 3 o Self-Discrepancy Theory Social-psychology theory that helps us achieve goals. A discrepancy (ex: failing a test) causes an emotion (anxiety) which leads to a behavior change (study more). Actual Self: what you’re currently accomplishing/doing Ideal Self: your goals & dreams Ought Self: other people’s expectations for you ^^^ if these are in line, you feel good. If they aren’t, you don’t feel good. Ex: your actual self fails a psychology test which doesn’t help your ideal self towards graduating (which is a goal), this discrepancy will change your behavior so hopefully you study more next time. - Motivation: factors that energize & direct behavior. o Why do you eat Because you’re motivated to. - Needs: primary factors that direct motivation. o Why do you eat Because you need food to survive. - Drives: psychological states that encourage behaviors to satiate needs. o When you haven’t eaten, you experience hunger which is an unpleasant state, it causes an uncomfortable feeling. Drive Reduction Theory - We need things: Primary Re-enforcers - Needs create arousal (usually negative) - We are driven to reduce arousal - Goal of D.R.Theory is Homeostasis or balance within o Like a thermostat don’t want to be too low or too high o Ghrelin causes hunger o Leptin causes satiety (positive emotions slow down and cease the arousal) How do people deal with emotions - What would you do if you failed a test How do you cope o nap, eat, cry, workout, play with a puppy - Problem Focused Coping o Dealing directly with the problem that caused the emotional distress in the first place. Ex) you fail, then you study harder next time. 4 o Reduces the likelihood that the problem will happen again in the future. - Emotion focused coping o Trying to cancel out the emotion by experiencing a positive emotion Ex) you fail a test and watch Netflix. o This one kinda sucks because the discrepancy is more likely to occur again with this strategy. Both PFC and EFC are used to alleviate negative emotion. Social Emotions: - They encourage behavior that retain & repair relationships. - Most emotions convey social meaning o Ex: if you’re happy, you smile, others see you smile and know you’re happy - They help us manage and maintain interpersonal success. o Examples of Social Emotions are guilt, embarrassment, Jealousy - Empathy: capabilities to experience others emotional states o Greatest social emotion o uses mirror neurons as seen in an FMRI of the brain. When you observe an action it produces neurological signals that’re similar to the ones we produce when we perform the action. We can do this in emotions too. some people lack empathy: psychopaths and children under 4. Positive-Negative asymmetry - Why have these discussions been so negative Because “bad is stronger than good.” - When comparing negative & positive emotions, scientists consistently found that bad events affect us more, last longer, are more pervasive in memory, and influence behavior more. - *People remember positive self-evaluation information; we remember the positive things about us better than the negative. * Hedonic treadmill: all animals want to attain pleasure & avoid displeasure. - We put a lot into attaining pleasure & don’t get anywhere because objective factors don’t influence happiness. Ex: working to get a raise, 5 a month after you get that raise you’re no longer excited about it and you’re working toward another reward. Theories of Personality - An individual’s characteristic pattern of thinking, feeling, and acting. Some are specific to an individual, but a lot are common for most humans. For example, the need to belong. - Personality distinguishes us, it’s enduring, dynamic & adaptive. Psychoanalytic Theory - Sigmund Freud o Clinical psychologist, medical doctor, and treated patients o Developed psychoanalysis and theory of personality - Freud’s Iceberg: The mind is like an iceberg: 10% happens consciously (above water), 90% happens unconsciously (below water), and in-between there’s the preconscious mind. o In the unconscious mind there is the ID, the pleasure principle with desires & wants made up of Eros & Thanatos. Eros: the drive for life (sex). Thanatos: the drive for death. o Superego: moral understanding of rules, laws, expectations of society taught by parents, religion, etc. This is what society wants, doesn’t get along with ID. It crosses all 3 levels of consciousness and is very controlling. o Ego: sometimes we need to indulge in our impulses, this is the balance between the ID and superego, “reality principle” o These 3 systems help us understand what make people different - The Structure of Personality o Ex) when they show an angel and a devil on someone’s shoulders in the movies. The angel represents the superego and the devil represents the ID while the main person is the ego. Psychoanalytic Theory Continued… - Have you ever accidentally let something slip out that you had been thinking This is called a Freudian slip and it is caused by conflict between your ID and superego. 6 - Defense Mechanisms on how to manage ID: o Repression: suppressing unconscious thoughts “actively forget it”. Ex) being sexually abused. o Reaction Formation: Reacting against one’s own unsatisfied impulses. Ex) you want a donut, you see someone eating a donut, you don’t like that person. o Rationalization: Developing an alternative explanation or excuse for undesired behavior. Ex) eating bad food when you’re drunk. Criticisms of Psychoanalysis - Most of what Freud said is: o Based on introspection & case studies, not scientific experimentation. o Difficult to test because if you’re subconsciously repressing, how can you study it o Sample problems Most subjects were wealthy females of the sexually Victorian era who were only able to talk about sex during a private session. What did Freud do right - Highlighted the possibility of non-biological causes for neuroses. - Said our unconscious mind is important & culturally brought attention to psychology. Humanistic Theory - A reaction/ compliment to psychoanalysis - Mentally healthy people - Believed people were fundamentally good - Emphasized personal growth - Abraham Maslow & the Hierarchy of Needs o Self-actualization on top: creativity & problem solving o Esteem: Self-esteem, confidence o Social needs: friends & family o Safety & security o Physiological needs: food, shelter, air, water, sleep, sex 7 8