This website uses cookies to ensure you have the best experience. Learn more

Jhyjryjryj Essay

1389 words - 6 pages

CICLO DI CARNOTIl ciclo di Carnot è un ciclo termico ideale e reversibile che ha due sorgenti a temperature diverse (T1 e T2).Il ciclo prevede scambi di calore con trasformazioni isoterme ed adiabatiche che consentono di tornare alle condizioni iniziali e generare lavoro meccanico dal calore.MACCHINE TERMICHESe in un motore s'incrementa il rapporto di compressione, ci si accorge che a parità di combustibile bruciato, si avrà un incremento dell'aria del ciclo termico, un incremento dell'energia ottenuto e quindi un incremento del rendimento della macchina.In altre parole si può definire un motore come un convertitore d'energia, capace di trasformare l'energia termica in lavoro meccanico, tramite la realizzazione di un ciclo termico il cui rendimento è strettamente legato al rapporto di compressione. Se non realizziamo le condizioni in alta pressione in cui avviene la combustione, otterremo solo calore ma non lavoro meccanico.Macchina a vaporeLa macchina a vapore è un sistema per produrre lavoro meccanico a spese dell'energia termica.Anche se le attuali macchine a vapore sono molto perfezionate, lo schema di base è sempre lo stesso: una sorgente di calore porta all'ebollizione una certa quantità di acqua producendo vapore che, espandendosi, preme sulle pareti del contenitore, mettendo in movimento un pistone. Usata per almeno due secoli come base per la costruzione di macchine industriali, per far viaggiare locomotive, navi e anche le prime automobili ed autocarri, la macchina a vapore, nella versione a turbina, trova ancora un uso importante nella produzione di energia nelle centrali nucleari o tradizionali e nelle grandi navi militari.Una macchina a vapore converte l'energia termica del vapore in lavoro meccanico. Questa macchina è costituita da un contenitore, il bollitore o caldaia, al cui interno, grazie all'azione di una fonte di calore, viene riscaldata acqua fino a temperature vicine all'ebollizione. In questo modo si ottiene vapore ad ad alta temperatura, che tende a espandersi in tutto il bollitore, o in un secondo contenitore in cui si riversa, esercitando una pressione sulle pareti tanto maggiore quanto più alta è la concentrazione del vapore stesso.Il vapore può venire convogliato, con tecniche molto diverse, su un pistone o in una turbina: sia il pistone, sia la turbina si mettono in moto per la pressione che ricevono, producendo lavoro meccanico. Ovviamente questo schema è molto semplificato, ma rende bene l'idea di come lavora una macchina di questo genere. Nel corso degli ultimi tre secoli ne sono state costruite di tipi diversi, nell'intento di migliorarne soprattutto l'efficienza, vale a dire la quantità di energia termica effettivamente trasformata in lavoro meccanico, che in queste macchine è particolarmente bassa, specie in quelle a pistone.Uno dei vantaggi della macchina a vapore risiede nel fatto che è possibile...

Find Another Essay On jhyjryjryj

Psychological Egoism Theory Essay

2240 words - 9 pages The theory of psychological egoism is indeed plausible. The meaning of plausible in the context of this paper refers to the validity or the conceivability of the theory in question, to explain the nature and motivation of human behavior (Hinman, 2007). Human actions are motivated by the satisfaction obtained after completing a task that they are involved in. For example, Mother Teresa was satisfied by her benevolent actions and

How Celtic Folkore has Influenced My Family

1587 words - 6 pages Every family has a unique background that influences the way they live and interact with other people. My parents, who emigrated from Ireland to the States with my three brothers in 1989, brought over their own Celtic folklore and traditions that have helped shaped the way our family operates and lives. One aspect of folklore that has helped shape my family dynamic is the Celtic cross—both its background and what role it has played in our lives

Julia Margaret Cameron

1406 words - 6 pages At a time when women were looked upon as being homemakers, wives, mothers and such the late 1850's presented a change in pace for one woman in specific. Photography was discovered in 1826 and soon after the phenomenon of photography was being experimented with and in turn brought new and different ways of photo taking not only as documenting real time, but also conceptualizing a scene in which an image would be taken. Julia Margaret Cameron will

Evaluation of School Improvement

1403 words - 6 pages The evaluation process should be progressive to incorporate overall planning, implement changes, which contribute to success. In order to focus on school climate and norms, the evaluation design must include the students, instructions, and outcomes to improve communication and building-level concerns to be address in this response. School Climate and Social Norms The school principal, other staff leaders, and personnel set the tone and the

Case Study: The Benefits of Animal Testing

1757 words - 7 pages Nine year old Amy has already had a rough start in life. She was born with an abnormal heart that hinders her everyday activities. Amy is unable to keep up with kids her own age because she often tires out easily. As a consequence, she has very little friends and is often alone. Amy is forced to take different medications everyday just to survive. Amy’s life consists of medicine, doctors, and constant hospital visits. However, Amy is due for a

Myth and Magic: Realism in "One Hundred Years of Solitude"

1531 words - 6 pages “He enjoyed his grandmother's unique way of telling stories. No matter how fantastic or improbable her statements, she always delivered them as if they were the irrefutable truth” (Wikipedia, 2011). Experiences are particular instances of one personally encountering or undergoing something and in these moments of time life changes for the best or the worst and memories are formed. These recollections such as riding your first bicycle, going to

Adiponectin: a Novel Indicator of Malnutrition and Inflammation in Hemodialysis Patients

2384 words - 10 pages Objective Protein-Energy malnutrition (PEM) and inflammation are common and overlapping conditions in hemodialysis patients which are associated with increased risk of morbidity and mortality. Adiponectin is an adipocytokine which is exclusively produced by adipose tissue. Few studies in hemodialysis patients have demonstrated that serum levels of adiponectin were significantly higher in malnourished patients compared to well-nourished ones. The

The Congo Free State: A Legacy of Apathy, Exploitation and Brutality

2298 words - 9 pages Between 1885 and 1908, Belgium’s Leopold II ruled Congo, a region in central Africa, as his personal colony, exploiting the resources and inhabitants for his own gain. Leopold allowed and encouraged Europeans and other Westerners to enter Congo and set up companies whose primary purpose was to gather rubber, which was abundant but difficult to get to in the Congo, using the Congolese as the laborers for the Europeans. Rubber gathering in Congo

Selective Exposition in The Lottery, by Shirley Jackson

1073 words - 4 pages Usually when someone hears the word “lottery” the first thing that comes to mind is a large sum of cash that people compete against highly impractical odds to win. Shirley Jackson’s story The Lottery might imply a similar conception based on the title alone, but the story is filled with unknowns never revealing exactly when and where the story takes place, or why the lottery exists; even what the lottery is isn’t revealed until the very end. Yet


1857 words - 7 pages INTRODUCTION I remember when I was a young child; I would always be scared whenever there was a severe storm outside that included thunder and lightning. This was especially true in the hours of darkness, when you could really see the lightning. As I grew older this so-called fear of lightning turned into a fascination for this weather phenomena. One of my most vivid memories of lightning as a young man was when I was flying to Florida, the

Maryland's Ecology and Environment

1130 words - 5 pages Maryland is the 42nd largest state, making it one of the smaller states in America. It is located in the South Atlantic region on the United States eastern seaboard. Prince George's is one of twenty four counties in Maryland. It is also the geographic center of the state. Maryland has a varied climate. The state is home to a variety of different ecosystems. This is also true of Maryland’s environment, which has the Atlantic Ocean on

Similar Essays

When The Bubble Burst Essay

1539 words - 6 pages By the time I arrived state side from my second tour in the Middle East the housing bubble had already burst. I noticed a drastic change in the way that many of my friends and family were living. Several of my friends that worked in real estate had sold their boats and seconds houses. My own stock portfolio had lost a third of its value. My sister and her husband had defaulted on their home mortgage leaving them scrambling for a place to live. I

Phase Diagram Essay

4456 words - 18 pages Introduction: Chemical equilibrium is a crucial topic in Chemistry. To represent and model equilibrium, the thermodynamic concept of Free energy is usually used. For a multi-component system the Gibbs free energy is a function of Pressure, Temperature and quantity (mass, moles) of each component. If one of these parameters is changed, a state change to a more energetically favorable state will occur. This state has the lowest free energy

Revolutionary Work Of Art Essay

1890 words - 8 pages Walter Benjamin emphasizes in his essay, “The Work of Art in the Age of its Technological Reproducibility” that technology used to make an artwork has changed the way it was received, and its “aura”. Aura represents the originality and authenticity of a work of art that has not been reproduced. The Sistine Chapel in the Vatican is an example of a work that has been and truly a beacon of art. It has brought a benefit and enlightenment to the art

Enlightenment Thought In New Zealand Schools

1594 words - 6 pages In this essay I will be looking at how the political and intellectual ideas of the enlightenment have shaped New Zealand Education. I will also be discussing the perennial tension of local control versus central control of education, and how this has been affected by the political and intellectual ideas of the enlightenment. The enlightenment was an intellectual movement, which beginnings of were marked by the Glorious Revolution in Britain