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SparkFun Robotics 101: Intro to Robotics

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What Are the Differences between Automation and Robotics

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China reboots manufacturing toward automation---What is China?

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Mining Industry -- The Future is Automation

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National Consortium for Mission Critical Operations

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This month scientists published rare footage of one of the Arctic's most elusive sharks. The findings demonstrate that, even with many technological advances in recent years, it remains a challenging task to document marine life up close.

But MIT computer scientists believe they have a possible solution: using robots.

In a paper out today, a team from MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) unveiled "SoFi," a soft robotic fish that can independently swim alongside real fish in the ocean.

During test dives in the Rainbow Reef in Fiji, SoFi swam at depths of more than 50 feet for up to 40 minutes at once, nimbly handling currents and taking high-resolution photos and videos using (what else?) a fisheye lens.

Using its undulating tail and a unique ability to control its own buoyancy, SoFi can swim in a straight line, turn, or dive up or down. The team also used a waterproofed Super Nintendo controller and developed a custom acoustic communications system that enabled them to change SoFi's speed and have it make specific moves and turns.

"To our knowledge, this is the first robotic fish that can swim untethered in three dimensions for extended periods of time," says CSAIL PhD candidate Robert Katzschmann, lead author of the new journal article published today in Science Robotics. "We are excited about the possibility of being able to use a system like this to get closer to marine life than humans can get on their own."

Katzschmann worked on the project and wrote the paper with CSAIL director Daniela Rus, graduate student Joseph DelPreto and former postdoc Robert MacCurdy, who is now an assistant professor at the University of Colorado at Boulder.
How it works
Existing autonomous underwater vehicles (AUVs) have traditionally been tethered to boats or powered by bulky and expensive propellers.

In contrast, SoFi has a much simpler and more lightweight setup, with a single camera, a motor, and the same lithium polymer battery that's found in consumer smartphones. To make the robot swim, the motor pumps water into two balloon-like chambers in the fish's tail that operate like a set of pistons in an engine. As one chamber expands, it bends and flexes to one side; when the actuators push water to the other channel, that one bends and flexes in the other direction.

These alternating actions create a side-to-side motion that mimics the movement of a real fish. By changing its flow patterns, the hydraulic system enables different tail maneuvers that result in a range of swimming speeds, with an average speed of about half a body length per second.

"The authors show a number of technical achievements in fabrication, powering, and water resistance that allow the robot to move underwater without a tether," says Cecilia Laschi, a professor of biorobotics at the Sant'Anna School of Advanced Studies in Pisa, Italy. "A robot like this can help explore the reef more closely than current robots, both because it can get closer more safely for the reef and because it can be better accepted by the marine species."

The entire back half of the fish is made of silicone rubber and flexible plastic, and several components are 3-D-printed, including the head, which holds all of the electronics. To reduce the chance of water leaking into the machinery, the team filled the head with a small amount of baby oil, since it's a fluid that will not compress from pressure changes during dives.

Indeed, one of the team's biggest challenges was to get SoFi to swim at different depths. The robot has two fins on its side that adjust the pitch of the fish for up and down diving. To adjust its position vertically, the robot has an adjustable weight compartment and a "buoyancy control unit" that can change its density by compressing and decompressing air.

Katzschmann says that the team developed SoFi with the goal of being as nondisruptive as possible in its environment, from the minimal noise of the motor to the ultrasonic emissions of the team's communications system, which sends commands using wavelengths of 30 to 36 kilohertz.

"The robot is capable of close observations and interactions with marine life and appears to not be disturbing to real fish," says Rus.

The project is part of a larger body of work at CSAIL focused on soft robots, which have the potential to be safer, sturdier, and more nimble than their hard-bodied counterparts. Soft robots are in many ways easier to control than rigid robots, since researchers don't have to worry quite as much about having to avoid collisions.

"Collision avoidance often leads to inefficient motion, since the robot has to settle for a collision-free trajectory," says Rus, the Andrew and Erna Viterbi Professor of Electrical Engineering and Computer Science at MIT. "In contrast, a soft robot is not just more likely to survive a collision, but could use it as information to inform a more efficient motion plan next time around."

As next steps the team will be working on several improvements on SoFi. Katzschmann plans to increase the fish's speed by improving the pump system and tweaking the design of its body and tail.

He says that they also plan to soon use the on-board camera to enable SoFi to automatically follow real fish, and to build additional SoFis for biologists to study how fish respond to different changes in their environment.

"We view SoFi as a first step toward developing almost an underwater observatory of sorts," says Rus. "It has the potential to be a new type of tool for ocean exploration and to open up new avenues for uncovering the mysteries of marine life."

This project was supported by the National Science Foundation.

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Soft robotic fish swims alongside real ones in coral reefs

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This month scientists published rare footage of one of the Arctic's most elusive sharks. The findings demonstrate that, even with many technological advances in recent years, it remains a challenging task to document marine life up close. But MIT computer scientists believe they have a possible solution: using robots.

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http://engineering.illinois.edu/news/article/21209

https://www.ece.illinois.edu/newsroom/article/21211

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83. MRI: Something more on protons spinning

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83. MRI: Something more on protons spinning

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Central Clinical School, Monash University

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How does MRI work? Jerome Maller explains

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79. MRI: Protons alignment, the easiest way!

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79. MRI: Protons alignment, the easiest way!

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77. Microwave oven 4: Now something a little bit ... slower! (BrE)

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77. Microwave oven 4: Now something a little bit ... slower! (BrE)

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https://www.youtube.com/watch?v=dPgV5xDZBng

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76. Microwave oven 3:  Well, let's go something ... deeper!

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76. Microwave oven 3:  Well, let's go something ... deeper!

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https://www.youtube.com/watch?v=i3ZsFOdveiU

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75.  Microwave oven 2: But how does it work, exactly???

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75.  Microwave oven 2: But how does it work, exactly???

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https://www.youtube.com/watch?v=MqsDPmnPKEk

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74. Microwave oven 1: An introduction (AmE)

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74. Microwave oven 1: An introduction (AmE)

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https://www.youtube.com/watch?v=kp33ZprO0Ck

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Geothermal energy and Biomass and biofuels

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Geothermal energy and Biomass and biofuels

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p 82-106

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Corretta grafia delle unità di misura - ElectroYou

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A volte vedo scritto kvar oppure Kvar, a volte KVAR. Ma com'è corretto scrivere: maiuscolo o minuscolo?

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Introduzione

Nell'arco della mia carriera di progettista di impianti elettrici e responsabile tecnico di varie società, mi è capitato spesso di sentir dire, soprattutto dagli addetti ai lavori; la tensione di rete è di 220 volts, oppure di ricevere documenti con le unità di misura scritte in modo non corretto, incomplete e, a volte, addirittura assolutamente incomprensibili.

E' bene ricordare che usare in modo scorretto nomi e simboli delle unità di misura e dei prefissi, equivale a compiere gravi errori di ortografia, che soprattutto nel campo della progettazione degli impianti elettrici ed elettronici, possono trasferire un'informazione del tutto diversa da quella che si intendeva fornire, con rischi addirittura di danno per chi la riceve e la interpreta secondo quanto erroneamente è stato scritto.

Al fine di chiarire un po' le idee è bene precisare alcuni concetti fondamentali delle unità di misura, della loro rappresentazione e soprattutto della loro corretta scrittura.

Concetti fondamentali

Si definisce misura un determinato procedimento mediante il quale si fa corrispondere un numero ad una grandezza fisica.

Per procedere alla misurazione di una grandezza, è necessario sceglierne un'altra della stessa specie da utilizzare come campione e assegnare ad essa il valore numerico uno, definendo cosi l'unità di misura. Le unità di misura definite direttamente da un campione, si chiamano " unità fondamentali" mentre quelle che utilizzano uno o più campioni delle unità fondamentali si chiamano " unità derivate". Fornire ad esempio l'informazione F = 50 è una espressione errata, anche se inserita in un contesto intuibile, una corretta informazione deve essere sempre rappresentata da una equazione dimensionale, per cui l'espressione corretta risulta F = 50 Hz, dove F rappresenta il simbolo della grandezza, in questo caso la frequenza, 50 è un numero puro che rappresenta il valore e Hz rappresenta l'unità di misura. Le unità di misura vengono rappresentate da un simbolo e sono codificate in base al Sistema Internazionale di unita di misura ( Systeme International d'unites) convenzionalmente abbreviato in SI, sistema introdotto nel 1960 dalla undicesima Conferenza Generale dei Pesi e Misure, in sostituzione dei vecchi sistemi CGS (centimetro, grammo, secondo) e MKS (metro, kilogrammo, secondo). .

Il Sistema Internazionale di unità di misura

In Italia il SI è stato adottato come sistema legale di misura obbligatorio con il DPR n°802 del 12 agosto 1982 "Attuazione della direttiva CEE 80/181 relativa alle unità di misura" e, successivamente adeguato alla direttiva CE 2009/3 dell'11 marzo 2009, con Decreto del Ministero dello sviluppo economico in data 29 ottobre 2009, ed è entrato definitivamente in vigore il 1° gennaio 2010.

Il DM del 29 ottobre 2009, attraverso l'adozione del SI, detta le regole di scrittura e stabilisce i simboli e il loro uso, proprio per fornire un modo uniforme e condiviso per le misure in tutti gli stati membri dell'unione europea, per questi motivi le regole del SI sono le uniche che danno certezza di non ambiguità e di non contestabilità in campo nazionale e internazionale. Il SI è oggetto di direttive della Comunità Europea e la divulgazione ed il controllo, nel nostro paese, sono affidati all' UNI (Ente Nazionale per l'Unificazione), mentre la vigilanza sull'applicazione del DPR 802/82 e successivo Decreto del 29 ottobre 2009, è demandata al Ministero dell'industria, del commercio e dell'artigianato che la esercita tramite l'ufficio centrale metrico e gli uffici provinciali metrici.

Compito dell'Ufficio Metrico è quello di vigilare affinchè sia fatto uso corretto delle unità di misura fondamentali e derivate secondo quanto prescritto dalle norme, nell'ambito non solo delle attività economiche, ma anche di quelle di carattere amministrativo e legale. Il SI è basato su sette unità fondamentali ed è noto come " sistema metrico decimale ", dove la parola metrico deriva dal greco misurare e la parola decimale fa riferimento alla base del sistema di relazione tra le misure che sono multiple o sottomultiple del dieci.

Le sette unita fondamentali sono:

metro(m), è la lunghezza del tragitto percorso dalla luce nel vuoto in un intervallo di 1/299 792 458 di secondo;

secondo(s), è la durata di 9.192.631.770 periodi della radiazione corrispondente alla transizione fra due livelli iperfini dello stato fondamentale dell'atomo di Cesio 133;

kilogrammo(kg), è l'unita di massa; esso e pari alla massa del prototipo internazionale del kilogrammo≫ prototipo realizzato in platino iridio nel 1889 e conservato a Sevres;

ampere(A), è l'intensità di una corrente elettrica costante che, mantenuta in due conduttori paralleli rettilinei di lunghezza infinita, di sezione circolare trascurabile, posti alla distanza di un metro l'uno dall'altro nel vuoto, produrrebbe fra questi conduttori una forza uguale a 2 x 10-7 newton su ogni metro di lunghezza;

kelvin(K), unità di temperatura termodinamica, è la frazione 1/273,16 della temperatura termodinamica del punto triplo dell'acqua;

mole(mol), è la quantità di sostanza di un sistema che contiene tante entità elementari quanti sono gli atomi in 0,012 kg di Carbonio 12. Quando si usa la mole, le entità elementari devono essere specificate; esse possono essere atomi, molecole, ioni, elettroni, altre particelle, oppure raggruppamenti specificati di tali particelle;

candela(cd), è l'intensità luminosa, in una data direzione, di una sorgente che emette una radiazione monocromatica di frequenza 540×10¹² hertz e la cui intensità energetica in tale direzione è 1/683 watt allo steradiante.

Fig.1: le 7 unità fondamentali

Sono alcune delle grandezze derivate del SI:

area, l'unità di misura adottata è il metro quadrato (m²);

volume, l'unità di misura adottata è il metro cubo (m³);

velocità, l'unità di misura è il metro al secondo (m/s);

accelerazione, l'unità di misura è il metro al secondo quadrato (m/s²);

densità di corrente elettrica, l'unità di misura è ampere al metro quadro (A/m²);

Intensità di campo elettrico, l'unità di misura è volt al metro (V/m);

Resistività elettrica, l'unità di misura è ohm per metro (Ω·m).

Fig.2: Diagramma delle relazioni tra le unita SI (dal NIST)

Spesso il progettista, soprattutto in elettronica, si trova a dover rappresentare grandezze molto grandi o molto piccole rispetto alle unità di misura, in questi casi il SI raccomanda di usare un prefisso che moltiplica (multiplo) o divide (sottomultiplo) l'unità di misura. Di seguito sono elencati i prefissi dei sottomultipli e dei multipli autorizzati dal SI, da notare che i sottomultipli dell'unità di misura devono essere scritti con lettere minuscole, mentre i multipli dell'unita di misura devono essere scritti con lettere maiuscole ad eccezione del kilo (k):

Qualora si debba ricorrere alla rappresentazione di una informazione caratterizzata da una determinata approssimazione, per convenzione si può indicare in modo esplicito, cioè riportando il valore più probabile seguito dal valore dell'incertezza come variazione in più o in meno, ad esempio F = 50 ± 0,5 Hz indica una frequenza il cui valore può essere compreso tra 49,5 e 50,5 Hz. Non esiste una convenzione generale per i simboli da usare per le grandezze, tranne per le unità fondamentali e derivate, essi dipendono molto dal contesto in cui vengono impiegati, è comunque buona norma attenersi alle seguenti regole generali:

scegliere per una data grandezza un simbolo che non provochi ambiguità con altri simboli scelti per altre grandezze o con i simboli delle unità di misura;

una volta scelto un simbolo per una grandezza non deve essere più cambiato nello stesso contesto.

Dal 1° gennaio 2010 in seguito al DM del 29 ottobre 2009, le seguenti grandezze non sono più ammesse legalmente:

quintale (q) sostituito da 100 kg;

atmosfera (atm) sostituita da 101.325 Pa;

cavallo vapore (CV) sostituito da 735,499 W;

caloria (cal) sostituita da 4,1868 J;

kilogrammo-forza (kgf) sostituito da 9,80665 N.

Alcune regole

Ai fini di una giusta interpretazione delle informazioni relative alle prescrizioni di progetto, la corretta scrittura dei nomi e dei simboli delle grandezze fisiche risulta di fondamentale importanza per il progettista. Di seguito si riportano le regole più importanti del SI riguardanti la scrittura delle grandezze, dei nomi e dei simboli delle unità; esse sono valide in generale, cioè anche per le unità che non appartengono al SI:

- Il SI stabilisce come unità di misura della temperatura il kelvin (K) e il grado Celsius (°C), pertanto una temperatura può essere espressa sia in kelvin che in gradi Celsius, la relazione che lega i due valori è la seguente: temperatura in gradi Celsius (t) = temperatura in kelvin (T) - 273,15. L'unità di temperatura si chiama kelvin non grado kelvin, mentre il simbolo °C si riferisce al grado Celsius e non più al grado centigrado che ormai è stato abbandonato;

- Nel caso di espressioni numeriche, i simboli delle unità di misura devono essere scritti in carattere normale, mentre i simboli delle grandezze possono essere scritti in carattere corsivo. Nello specifico quelle costanti nel tempo si indicano con simboli corsivi maiuscoli, mentre quelle variabili nel tempo si indicano con simboli corsivi minuscoli. In questo modo si evita confusione quando la stessa lettera è usata sia per la grandezza che per la sua unità di misura, ad esempio scrivendo: V (corsivo) = 12 V si intende in modo inequivocabile, che si tratta di una tensione continua del valore di dodici volt, invece se si scrive: v (corsivo) = 12 V si intende in modo inequivocabile, che si tratta di una tensione alternata di dodici volt, per cui non devono essere assolutamente usate le incomprensibili sigle: c.c., c.a., cc, ca, CC, CA, ecc;

- I nomi delle unità di misura vanno sempre scritti con la lettera iniziale minuscola, privi di accenti o di altri segni grafici, eccetto quando il nome è la prima parola di una frase, fa eccezione l'unità grado Celsius;

- I nomi delle unità di misura, se derivano da un nome proprio, sono invariati al plurale;

- L'unità di misura se non e accompagnata dal valore numerico, deve essere scritta per esteso e non con il simbolo, fatta eccezione per i disegni, prospetti, ecc.;

- Nelle elaborazioni numeriche, per evitare errori, si raccomanda l'uso delle unità SI e non dei loro multipli o sottomultipli, tuttavia per esprimere i dati di elaborazioni numeriche o di misurazioni ove le cifre significative siano poche, è possibile usare quel suo multiplo o sottomultiplo che dia luogo a valori numerici che comprendano soltanto le cifre significative. Ad esempio invece di scrivere 0,00282 m è preferibile scrivere 2,82 mm; invece di scrivere 0,000348 m ³ è preferibile scrivere 348 mm ³; invece di scrivere 2 000 000 Hz è preferibile scrivere 2 GHz; invece di scrivere 0,0035 A è preferibile scrivere 3,5 mA. Si può derogare da questa raccomandazione quando si ritiene necessario utilizzare, in un determinato contesto, un'unica grandezza di misura al fine di evitare eventuali ambiguità ed incomprensioni;

- I simboli vanno sempre scritti con la lettera iniziale minuscola, tranne quelli derivanti da nomi propri;

- Il simbolo non deve essere seguito da un punto, salvo che si trovi a fine periodo;

- Il simbolo deve sempre seguire il valore numerico;

- Il simbolo del multiplo o del sottomultiplo deve precedere il simbolo dell'unità di misura senza l'interposizione di un punto o di uno spazio;

- Il prefisso kilo (k) deve essere minuscolo, la lettera K maiuscola indica la temperatura in kelvin;

- Il prodotto di due o più unità va indicato con un punto a metà altezza o con un piccolo spazio tra i simboli;

- Il prodotto di una unita per se stessa n volte, va indicato con una potenza dell'unità e non con abbreviazioni ad esempio m ² non mq o Mq oppure m ³ non mc o Mc;

- Il quoziente tra due unità va indicato con una barra obliqua o con esponenti negativi;

- I simboli di ora, minuto, secondo devono essere rispettivamente h, min, s;

- I simboli monetari precedono il numero al quale si riferiscono;

- La separazione fra numeri interi e decimali deve essere effettuata utilizzando la virgola (è ammesso il punto per i testi in lingua inglese), sia a sinistra della virgola (parte intera), sia a destra della virgola, i numeri possono essere raggruppati in gruppi di tre cifre separati tra loro da uno spazio leggermente superiore allo spazio tra le cifre, i numeri raggruppati non possono essere mai separati da punti;

- Gli elementi che costituiscono una data in forma esclusivamente numerica devono essere scritti nell'ordine seguente: anno (4 cifre) - mese (2 cifre) - giorno(2 cifre);

- I coefficienti (numero di atomi nella molecola) nei simboli dei composti chimici, si scrivono in basso a destra del simbolo dell'elemento al quale si riferiscono;

- Tra un numero e una potenza del 10 va inserito solo un punto a mezza altezza, mentre tra i simboli letterali è possibile inserire o un punto a mezza altezza o uno spazio.

Alcuni esempi di rappresentazione delle unità di misura:

230 V - duecentotrenta volt

230 volt - V 230 - duecentotrenta volts

v (corsivo) = 230 V ± 10%

Vca 230 ± 10% - Vac 230 ± 10% - 230 Vac ± 10%

V(corsivo) = 24 V ± 5%

Vcc 24 ± 5% - VCC 24 ± 5% - 24 Vcc ± 5%

50 Hz - cinquanta hertz

50 hz - cinquanta Hz - Hz 50

16 A - sedici ampere

16 ampere - 16 Amp - sedici amperes

6 kA - sei kiloampere

6 KA - 6 ka - kA 6 - sei Kiloampere

3 kW - tre kilowatt

3 KW - tre kWatt - 3 Kw - kW 3

6 kWh - sei kilowattora

6 KWH - sei kiloWattora - kWh 6 - 6 kilowattora

10 kΩ - dieci kilohm

10 KΩ - 10 kiloΩ - 3 kilohm - kΩ 10

10 MΩ - dieci megaohm

10 Mohm - MΩ 10 - 10 megaohm

10 μF - dieci microfarad

10 microfarads - μF 10 - dieci μF

6 S - sei siemens

S 6 - sei Siemens - sei S - 6 s

5 °C - cinque gradi Celsius

5° - 5 gradi °C - °C 4

2 Pa - due pascal

Pa 2 - due Pascal - due pa

4 N - quattro newton

N 4 - 4 newton - quattro N

80 m - ottanta metri

80 mt - m 80 - 80 metri lineari - Mt 80

4 m ² - quattro metri quadrati

4 mq - m ² 4 - 4 metri quadrati

9 m ³ - nove metri cubi

9 mc - 9 metri cubi - m ³ 9

8 lx - otto lux

8 lux - otto lx - lx 8

5 s - cinque secondi

5 sec - s 5 - 5 s. - 5 secondi

8 min - otto minuti

8 min. - otto min - min 8

2 h - due ore

2 H - 2 ore - h 2 - ore 2

2 kg - due kilogrammi

3 Kg - tre kili - kg 3 - il peso è di tre kilogrammi

2014-03-26 - 26 marzo 2014

26-03-2014 - 26-3-14 - 2014-3-9

€ 500 - $ 400

500 € - 400 $

2 500 - 3 235 436 2.500 - 2500 - 3.235.436 - 3235436

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Le unità di misura: rappresentazione e regole di scrittura - Meccanismo Complesso

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Introduzione Nell'arco della mia carriera di progettista di impianti elettrici e responsabile tecnico di varie società, mi è capitato spesso di sentir dire, soprattutto dagli addetti ai lavori; la tensione di rete è di 220 volts, oppure di ricevere documenti con le unità di misura scritte in modo non ...

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KICD test - 1.2.1.5 Conductors and non-conductors of electricity

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Most metals have free electrons and are good conductors- silver, copper, gold, aluminium, iron. While plastics, glass, and ceramics are good insulators, they conduct almost no current at all. That's what makes them safe to hold the cable even when there's current running on the inside. No, don't cut that.

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How Small Is An Atom? Spoiler: Very Small.

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http://mitsloan.mit.edu/newsroom/articles/the-real-barriers-to-electric-vehicle-adoption/

https://www.cleanenergynews.co.uk/news/transport/intelligent-charging-must-tackle-last-real-barrier-to-evs-in-grid-constrain

https://www.theengineer.co.uk/issues/march-2014-online/barriers-to-electric-car-uptake/

https://www.forbes.com/sites/energyinnovation/2017/10/10/five-ways-utilities-can-gain-from-building-electric-vehicle-charging-infrastructure/#44168098324d

https://www.theguardian.com/environment/2018/feb/27/lack-of-models-not-charging-points-holding-back-electric-car-market

https://www.power-technology.com/features/featureprepping-power-grids-for-the-electric-vehicle-revolution-4983190/

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Have a look to possible summaries of subjects in Unit 6.

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54. Microchips: They can save the planet!

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54. Microchips: They can save the planet!

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https://www.youtube.com/watch?v=B2G4zmW8Gsk

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http://computer.howstuffworks.com/cpu-quiz.htm

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https://www.youtube.com/watch?v=YIkMaQJSyP8

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https://www.youtube.com/watch?v=d9SWNLZvA8g

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https://www.youtube.com/watch?v=Fxv3JoS1uY8

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53. Integrated circuits: Let's go inside!

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53. Integrated circuits: Let's go inside!

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https://www.youtube.com/watch?v=BpTo76QOT2k

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50. Integrated circuits: Have some fun in Harvard!

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50. Integrated circuits: Have some fun in Harvard!

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https://www.youtube.com/watch?v=NGh_ix8CDkE

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48. Integrated circuits: Here an overview.

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48. Integrated circuits: Here an overview.

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https://www.youtube.com/watch?v=RECNeKNzUf8

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Electric cars - why don't people buy them? | Made in Germany - Talk

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EV vs ICE Vehicles: Electric Cars Are Our Future and They're Greener than You Think

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Electric Cars & Global Warming Emissions

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39. How does an electric car work? Tesla Model S!

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39. How does an electric car work? Tesla Model S!

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by Mattia Castioni, Luca Rascacci & Saiad Ayoub Oulad

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How does an Electric Car work ? | Tesla Model S

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Have a look to possible summaries of subjects in Unit 6

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This is more difficult, yet with many pictures and data

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Geo Energy Hub - Renewable Energy Solutions and Tech Experts

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Welcome to Geo Energy Hub Your Go-To Source For Everything Green Energy and Tech Let's build a cleaner, sustainable future together by utilizing solar, wind, water, nuclear and geothermal energy in a better way. Learn About Green Energy and Tech Our team of renewable energy experts are dedicated to providing the best possible information on [...]

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This is the easiest site

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An official website of the United States government.

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A good site to start with

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In the modern day, most people prioritize comfort and efficiency in their homes. How people heat and cool their homes determines the efficient realization of those priorities. A 5600 square foot home, for example, can explode your energy bills if cooling and heating systems are not efficient. The use of conventional electricity for heating and cooling greatly contributes to spike in energy bills. Conventional electricity is generated using fossil fuels such as coal and oil. With these fossil fuel sources running dangerously low, one source that humans have barely exploited, called geothermal energy, could provide attractive possibilities for bridging that gap and saving you massive energy costs. Geothermal systems take advantage of the natural warmth of the earth to heat and cool your home.

Geothermal energy is energy harvested from the heat found deep beneath the surface of the earth. The internal heat of the earth forms as a result of radioactive decay of minerals and consistent heat loss from the original earth formation. It's is a clean and renewable form of energy because it's infinite and doesn't contribute to any greenhouse gas emission.

Energy inside the earth is never going to deplete and will remain as a source of heat, for millions and millions of years and we can harness that energy that is going to be cheaper and can help us to reduce our dependence on fossil fuels and global warming and public health issues that result from their use.

How Geothermal Energy Works?

The core found beneath the earth's crust harbors a lot of heat. The deeper you go underneath the surface of the earth, the hotter it becomes. The core, which is approximately 6, 437 kilometers or 4,000 miles below the surface of the earth, can achieve temperatures of about 4200 degree Celsius or 7,600 degrees Fahrenheit. A portion of that heat emanated from the earth formation process approximately 4 billion years ago.

The remaining heat stems from continuous decomposition of radioactive materials underneath the earth. The heat found inside the core of the earth is so extreme that it melts rocks found nearby. The melted rock is called magma. Since magma is less dense than rocks wrapping around it, it's forced up the surface of the earth. On some instances, the pressure inside the core forces magma out through vents, erupting out to the surface, a phenomenon known as volcanic eruption. However, in most instances, magma doesn't come out of the earth's crust. Instead, it heats rocks nearby, plus the water trapped within these rocks.

In some instances, the heating of water causes pressure to build up inside and forces the water to escape through vents in the earth culminating into pools of hot water commonly referred to as hot springs or ruptures of steam and hot water, commonly known as Geysers. Heated water that remains under the earth surface form pools known as geothermal reservoirs.

To get that heat, water is pumped down an "injection well". Then it filters through the cracks in the rocks where they are at a high temperature. The water then returns via the "recovery well" under pressure in the form of steam. That steam is captured and is used to drive electric generators.

To produce geothermal energy, the hot water from the geothermal reservoir must be tapped. There are three techniques used to tap this hot water:

This technique is used in locations where geothermal reservoirs and hot springs are in proximity to the surface of the earth. Vents are drilled from the ground to the geothermal reservoir and the hot water pumped directly to homes and buildings for heating purposes. The hot water is pumped via a heat exchanger that transmits the heat from the hot water into the home's heating system. The used water is then allowed to flow back into the geothermal reservoir to be reheated, and the cycle continues.

A geothermal heat pump is sometimes called ground source heat pump. It's a central cooling and heating system, which conveys heat to and from the ground. It leverages the earth as a heat source during winter months and a heat sink during summer months.

Ideally, geothermal heat pump works a lot like the traditional heat pump. It utilizes high-pressure refrigerant to harness and transfer heat in and out of the house. The only difference is that a traditional heat pump captures the heat and releases it to the atmosphere. A geothermal heat pump conveys heat into and out of the building via long loops of pipe filled with liquid buried under the ground. An electric compressor and heat exchanger installed in the building sucks up the heat from the pipes and delivers it throughout the building through a duct system. The geothermal heat pump works exactly the opposite during summer. The pipes suck heat away from the building and transfer it to the ground for absorption.

Geothermal power plants generally harness the heat underneath the earth's crust and use it to generate electricity. There are three kinds of geothermal power plants:

Here, hot steam is harnessed directly from geothermal reservoirs and transmitted to geothermal power plant where it turns a turbine. The turbine then triggers a generator to produce electricity.

Here, water at a temperature of 148 to 371 degrees Celsius is sucked up from the geothermal reservoir through drilled down pipes. Some of the water is converted to steam and directed to spin turbines that trigger a generator to produce electricity. The steam is then allowed to cool off and eventually turns to water. The water is directed back to the geothermal reservoir to heat up and continue the cycle.

Binary cycle plants use moderately hot water. The water is transferred via a heat exchanger. In the exchanger, the heat of the water is conveyed to a liquid, like isobutene, which boils at a comparatively lower temperature than water. When the liquid is subjected to heat, it converts to steam. The steam is directed to turn a turbine, which spooks a generator to produce electricity.

How much geothermal energy can be useful depends on several factors for e.g.: location, how hot the water gets, the rocks inside the earth and amount of water pumped into the area. If the rocks are not hot enough or cool down naturally this presents a problem for geothermal power stations.

Examples of geothermal energy

Geysers

A Geyser is a hot spring where water sporadically boils, sending a long column of steam and water into the atmosphere. It's quite an amazing spectacle. Nonetheless, some Geysers result in eruptions that burst thousands if not hundreds of liters of hot water up hundreds of feet into the atmosphere. The world's famous Geyser is the Old Faithful situated in Yellowstone National Park in the United States. It's known to erupt each 60 to 90 minutes. For a Geyser to occur, the following conditions must be present:

Scorching rocks underneath the earth's surface

Ground water source

A subsurface water reservoir

Vents that enable water to be conveyed to the surface

Geysers are extremely rare phenomenon. United States, Russia, Chile, New Zealand and Iceland are countries that harbor active Geysers.

Hot Springs

Hot springs are springs that come about due to the appearance of geothermally heated groundwater that comes out from the earth's crust. Geothermal hot springs occur at different locations in the earth's crust. Some hot springs contain water at a perfect temperature for bathing. Others are so hot that anyone trying to bath in them can sustain severe burns or die.

Fumaroles

A fumarole is a vent from which steam and gasses escape into the atmosphere. The vent can be utilized to tap geothermal energy. Fumaroles may form along small cracks or long fissures, in chaotic fields or clusters. They may also form on lava flow surfaces and huge deposits of pyroclastic flows. They may occur for decades or even centuries if they form on top of a constant heat source like active magma. They might well disappear within weeks or months if they form on top of a fresh volcanic deposit that quickly cools. Their temperature range from 70 to 100 degrees Celsius.

The only concern about geothermal energy is that it releases hydrogen sulfide. Hydrogen sulfide is a kind of gas that smells a lot like rotten egg. Otherwise, the advantages of geothermal energy are simply overwhelming. It's clean, green, renewable, relatively inexpensive, and cuts backs on the use of fossils fuels, which contribute to massive pollution and global warming.

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What is Geothermal Energy and How Geothermal Energy Works - Conserve Energy Future

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Geothermal energy is energy harvested from the heat found deep beneath the surface of the earth. The internal heat of the earth forms as a result of radioactive decay of minerals and consistent heat loss from the original earth formation.

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Geodynamics, presented by the Australian Geothermal Energy Association (AGEA). http://www.agea.org.au

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🌏 earthrise - How it works: Geothermal Electricity

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by me

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12. Wind turbine terminology and Components

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by me

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How does a wind turbine work? | Sustainability - ACCIONA

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by Mirco Marcazzan's group
http://windeis.anl.gov/guide/basics/

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by Luca Caprara's group

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Wind turbines work on a simple principle: instead of using electricity to make wind-like a fan-wind turbines use wind to make electricity. Wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity.

Wind is a form of solar energy caused by a combination of three concurrent events:

1. The sun unevenly heating the atmosphere

2. Irregularities of the earth's surface

3. The rotation of the earth.

Wind flow patterns and speeds vary greatly across the United States and are modified by bodies of water, vegetation, and differences in terrain. Humans use this wind flow, or motion energy, for many purposes: sailing, flying a kite, and even generating electricity.

The terms "wind energy" and "wind power" both describe the process by which the wind is used to generate mechanical power or electricity. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity.

A wind turbine turns wind energy into electricity using the aerodynamic force from the rotor blades, which work like an airplane wing or helicopter rotor blade. When wind flows across the blade, the air pressure on one side of the blade decreases. The difference in air pressure across the two sides of the blade creates both lift and drag. The force of the lift is stronger than the drag and this causes the rotor to spin. The rotor connects to the generator, either directly (if it's a direct drive turbine) or through a shaft and a series of gears (a gearbox) that speed up the rotation and allow for a physically smaller generator. This translation of aerodynamic force to rotation of a generator creates electricity.

Types of Wind Turbines

The majority of wind turbines fall into two basic types:

Wind turbines can be built on land or offshore in large bodies of water like oceans and lakes. The U.S. Department of Energy is currently funding projects to facilitate offshore wind deployment in U.S. waters.

Applications of Wind Turbines

Modern wind turbines can be categorized by where they are installed and how they are connected to the grid:

Distributed Wind

When wind turbines of any size are installed on the "customer" side of the electric meter, or are installed at or near the place where the energy they produce will be used, they're called "distributed wind.

Many turbines used in distributed applications are small wind turbines. Single small wind turbines-below 100 kilowatts-are typically used for residential, agricultural, and small commercial and industrial applications.

Small turbines can be used in hybrid energy systems with other distributed energy resources, such as microgrids powered by diesel generators, batteries, and photovoltaics.

These systems are called hybrid wind systems and are typically used in remote, off-grid locations( where a connection to the utility grid is not available) and are becoming more common in grid-connected applications for resiliency.

Learn more about distributed wind from the Distributed Wind Animation or read about what the Wind Energy Technologies Office is doing to support the deployment of distributed wind systems for homes, businesses, farms, and community wind projects.

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Wind turbines work on a simple principle: instead of using electricity to make wind-like a fan-wind turbines use wind to make electricity. Wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity.

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by Edoardo Tinelli's group

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From massive wind farms generating power to small turbines powering a single home, wind turbines around the globe generate clean electricity for a variety of power needs.

In the United States, wind turbines are becoming a common sight. Since the turn of the century, total U.S. wind power capacity has increased more than 24-fold. Currently, there's enough wind power capacity in the U.S. to generate enough electricity to power more than 15 million homes, helping pave the way to a clean energy future.

What is a Wind Turbine?

The concept of harnessing wind energy to generate mechanical power goes back for millennia. As early as 5000 B.C., Egyptians used wind energy to propel boats along the Nile River. American colonists relied on windmills to grind grain, pump water and cut wood at sawmills. Today's wind turbines are the windmill's modern equivalent -- converting the kinetic energy in wind into clean, renewable electricity.

How Does a Wind Turbine Work?

The majority of wind turbines consist of three blades mounted to a tower made from tubular steel. There are less common varieties with two blades, or with concrete or steel lattice towers. At 100 feet or more above the ground, the tower allows the turbine to take advantage of faster wind speeds found at higher altitudes.

Turbines catch the wind's energy with their propeller-like blades, which act much like an airplane wing. When the wind blows, a pocket of low-pressure air forms on one side of the blade. The low-pressure air pocket then pulls the blade toward it, causing the rotor to turn. This is called lift. The force of the lift is much stronger than the wind's force against the front side of the blade, which is called drag. The combination of lift and drag causes the rotor to spin like a propeller.

A series of gears increase the rotation of the rotor from about 18 revolutions a minute to roughly 1,800 revolutions per minute -- a speed that allows the turbine's generator to produce AC electricity.

A streamlined enclosure called a nacelle houses key turbine components -- usually including the gears, rotor and generator -- are found within a housing called the nacelle. Sitting atop the turbine tower, some nacelles are large enough for a helicopter to land on.

Another key component is the turbine's controller, that keeps the rotor speeds from exceeding 55 mph to avoid damage by high winds. An anemometer continuously measures wind speed and transmits the data to the controller. A brake, also housed in the nacelle, stops the rotor mechanically, electrically or hydraulically in emergencies. Explore the interactive graphic above to learn more about the mechanics of wind turbines.

Types of Wind Turbines

There are two basic types of wind turbines: those with a horizontal axis, and those with a a vertical axis.

The majority of wind turbines have a horizontal axis: a propeller-style design with blades that rotate around a horizontal axis. Horizontal axis turbines are either upwind (the wind hits the blades before the tower) or downwind (the wind hits the tower before the blades). Upwind turbines also include a yaw drive and motor -- components that turns the nacelle to keep the rotor facing the wind when its direction changes.

While there are several manufacturers of vertical axis wind turbines, they have not penetrated the utility scale market (100 kW capacity and larger) to the same degree as horizontal access turbines. Vertical axis turbines fall into two main designs:

Drag-based, or Savonius, turbines generally have rotors with solid vanes that rotate about a vertical axis.

Lift-based, or Darrieus, turbines have a tall, vertical airfoil style (some appear to have an eggbeater shape). The Windspire is a type of lift-based turbine that is undergoing independent testing at the National Renewable Energy Laboratory's National Wind Technology Center.

Wind Turbine Applications

Wind Turbines are used in a variety of applications - from harnessing offshore wind resources to generating electricity for a single home:

Large wind turbines, most often used by utilities to provide power to a grid, range from 100 kilowatts to several megawatts. These utility-scale turbines are often grouped together in wind farms to produce large amounts of electricity. Wind farms can consist of a few or hundreds of turbines, providing enough power for tens of thousands of homes.

Small wind turbines, up to 100 kilowatts, are typically close to where the generated electricity will be used, for example, near homes, telecommunications dishes or water pumping stations. Small turbines are sometimes connected to diesel generators, batteries and photovoltaic systems. These systems are called hybrid wind systems and are typically used in remote, off-grid locations, where a connection to the utility grid is not available.

Offshore wind turbines are used in many countries to harness the energy of strong, consistent winds found off of coastlines. The technical resource potential of the winds above U.S. coastal waters is enough to provide more than 4,000 gigawatts of electricity, or approximately four times the generating capacity of the current U.S. electric power system. Although not all of these resources will be developed, this represents a major opportunity to provide power to highly populated coastal cities. To take advantage of America's vast offshore wind resources, the Department is investing in three offshore wind demonstration projects designed to deploy offshore wind systems in federal and state waters by 2017.

Future of Wind Turbines

To ensure future growth of the U.S. wind industry, the Energy Department's Wind Program works with industry partners to improve the reliability and efficiency of wind turbine technology, while also reducing costs. The program's research efforts have helped to increase the average capacity factor (a measure of power plant productivity) from 22 percent for wind turbines installed before 1998 to more than 32 percent for turbines installed between 2006 and 2012. Wind energy costs have been reduced from more than 55 cents per kilowatt-hour (kWh) in 1980 to under 6 cents/kWh today in areas with good wind resources.

Wind turbines offer a unique opportunity to harness energy in areas where our country's populations need it most. This includes offshore wind's potential to provide power to population centers near coastlines, and land-based wind's ability to deliver electricity to rural communities with few other local sources of low carbon power.

The Energy Department continues working to deploy wind power in new areas on land and at sea and ensuring the stable, secure integration of this power into our nation's electrical grid.

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From massive wind farms generating power to small turbines powering a single home, wind turbines around the globe generate clean electricity for a variety of power needs. In the United States, wind turbines are becoming a common sight. Since the turn of the century, total U.S. wind power capacity has increased more than 24-fold.

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by Luca Rascacci's group

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An overview of the layout of utility-class wind turbine generators - where are the major components, what do they do, and what differences can be found between models and size ranges.

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by Mattia Castioni's group

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Construction of Three Phase Induction Motor - Magic Marks

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Dragonfly Education is an education company, that is building proprietary education content for higher learning in technical streams. We are enabling B.Tech engineering students to learn more effectively using our solution, called MasterClass™ and our proprietary process called the Theory of Organised Learning™. The Dragonfly solution combines classroom education with an online learning management system.

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Working Principal of Three Phase Induction Motor - Magic Marks

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Dragonfly Education is an education company, that is building proprietary education content for higher learning in technical streams. We are enabling B.Tech engineering students to learn more effectively using our solution, called MasterClass™ and our proprietary process called the Theory of Organised Learning™. The Dragonfly solution combines classroom education with an online learning management system.

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In-wheel motors are not a new concept, but they are new to the modern vehicle development process. Here is why they make sense over more customary in-board electric drive solutions.

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Asynchronous Induction Motor. How does it work.avi

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A linear electric motor is constructed and its operation explained.

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This video demonstrates how to build a simple electric motor. Includes a discussion of some of the science behind electric motors.