Spectrophotometer Essay Example for Free

Spectrophotometer Essay Spectrophotometry in chemistry is a quantitative measure of the reflection or transmission of material properties as a function of wavelength. It is more specialized than the term electromagnetic spectroscopy which is general in that spectrophotometry deals with near-ultraviolet, visible light, and near-infrared, but doesn’t cover the techniques of time-resolved spectroscopic . Spectrophotometer is used in Spectrophotometry. A spectrophotometer is a photometer that measures the intensity as a function of the wavelength of the light source. Important features of spectrophotometers are linear range of absorption or reflectance measurement spectral and bandwidth. A spectrophotometer is used commonly for the transmittance measurement or solutions reflectance, opaque solids or transparent, such as gases, or polished glass. However they can be designed to measure the diffusivity of any of the listed light ranges that which cover around 200nm 2500nm using different calibrations and controls. Calibrations are needed on the machine, within these ranges of light, using standards which vary in type depending on the wavelength of the photometric determination. An example for spectrophotometry experiment is used is the determination of the solution equilibrium constant. A specific chemical reaction in a solution may occur in a reverse and forward direction where products break down into reactants and reactants form products. At some point, this chemical reaction will reach a point of balance called an equilibrium point. In order to determine the respective concentrations of products and reactants at this point, the light transmittance of the solution can be tested using spectrophotometry. The amount of light that passes through the solution the concentration of certain chemicals is indicative that do not allow light to pass through. The use of spectrophotometers spans various scientific fields, such as materials science, physics, biochemistry, molecular biology , and chemistry. They are widely used in many industries including semiconductors, laser and optical manufacturing, printing and forensic examination, and as well in laboratories for the chemical substances study. Ultimately, a spectrophotometer is able to determine, depending on the control or calibration, what substances are present in a target and exactly how much through calculations of observed wavelengths. IR Spectroscopy Infrared spectroscopy (IR spectroscopy) is the spectroscopy that deals with the infrared region of the electromagnetic spectrum that is light with a longer wavelength and lower frequency than visible light. It covers a range of techniques, mostly based on absorption spectroscopy. As with all spectroscopic techniques, it can be used to identify and study chemicals. A common laboratory instrument that uses this technique is a Fourier transform infrared (FTIR) spectrometer. The infrared portion of the electromagnetic spectrum is usually divided into three regions; the near-, mid- and far- infrared, named for their relation to the visible spectrum. The higher-energy near-IR, approximately 14000–4000 cm−1 (0.8–2.5 ÃŽ ¼m wavelength) can excite overtone or harmonic vibrations. The mid-infrared, approximately 4000–400 cm−1 (2.5–25 ÃŽ ¼m) may be used to study the fundamental vibrations and associated rotational-vibrational structure. The far-infrared, approximately 400–10 cm−1 (25–1000 ÃŽ ¼m), lying adjacent to the microwave region, has low energy and may be used for rotational spectroscopy. The names and classifications of these sub regions are conventions, and are only loosely based on the relative molecular or electromagnetic properties. Types There are two basic types of infrared spectrometers. Fourier transform infrared (FTIR) spectrometers are single-beam instruments that use an interferometer to spread a sample with infrared light and measure the intensity of the infrared light not absorbed by the sample. The application of a Fourier transform converts the resulting time domain digital signal into a frequency domain digital signal. Dispersive infrared spectrometers use visible lasers, a grating, and charged coupled devices (CCDs) to collect data. The laser acts as a light source and irradiates the sample. Most of the radiation scatters elastically at the same energy as the incoming laser radiation. A small amount, approximately one photon in a million (0.00001%), scatters from the sample at a wavelength shifted slightly from the original wavelength. Techniques * Fourier transforms infrared spectroscopy FTIR redirects here. FTIR may also refer to frustrated total internal reflection. Fourier transform infrared spectroscopy (FTIR) is a technique which is used to obtain an infrared spectrum of absorption, emission, photoconductivity or Raman scattering of a solid, liquid or gas. An FTIR spectrometer simultaneously collects spectral data in a wide spectral range. This confers a significant advantage over a dispersive spectrometer which measures intensity over a narrow range of wavelengths at a time. FTIR has made dispersive infrared spectrometers all but obsolete (except sometimes in the near infrared), opening up new applications of infrared spectroscopy. The term Fourier transform infrared spectroscopy originates from the fact that a Fourier transform (a mathematical process) is required to convert the raw data into the actual spectrum. * Near IR spectroscopy Near-infrared spectroscopy (NIRS) is a spectroscopic method that uses the near-infrared region of the electromagnetic spectrum (from about 800 nm to 2500 nm). Typical applications include pharmaceutical, medical diagnostics (including blood sugar and pulse oximetry), food and agrochemical quality control, and combustion research, as well as research in functional neuroimaging, sports medicine science, elite sports training, ergonomics, rehabilitation, neonatal research, brain computer interface, urology (bladder contraction) and neurology (neurovascular coupling). Theory: Near-infraredspectroscopy is based on molecular overtone and combination vibrations. Such transitions are forbidden by the selection rules of quantum mechanics. As a result, the molar absorptivity in the near IR region is typically quite small. One advantage is that NIR can typically penetrate much farther into a sample than mid infrared radiation. Near-infrared spectroscopy is, therefore, not a particularly sensitive technique, but it can be very useful in probing bulk material with little or no sample preparation. The molecular overtone and combination bands seen in the near IR are typically very broad, leading to complex spectra; it can be difficult to assign specific features to specific chemical components. Multivariate (multiple variables) calibration techniques (e.g., principal components analysis, partial least squares, or artificial neural networks) are often employed to extract the desired chemical information. Careful development of a set of calibration samples and application of multivariate calibration techniques is essential for near-infrared analytical methods. Applications: The primary application of NIRS to the human body uses the fact that the transmission and absorption of NIR light in human body tissues contains information about hemoglobin concentration changes. When a specific area of the brain is activated, the localized blood volume in that area changes quickly. Optical imaging can measure the location and activity of specific regions of the brain by continuously monitoring blood hemoglobin levels through the determination of optical absorption coefficients. Typical applications of NIR spectroscopy include the analysis of foodstuffs, pharmaceuticals, combustion products and a major branch of astronomical spectroscopy.

What is an American? :: essays research papers

Let me ask you this: What is an American? There is no right or wrong way to answer this question. It is diffucult to compare an American today to an American two-hundred and fifty years ago, because the modern day America is so diverse that a label cannot be stuck on the forehead of today's society. There are many different ways that one can describe an American today, infact there are so many ways that I could never come close to covering all of them in this essay. I feel the three most effective ways to describe today's American are by the persons age, his or her priorities in life, and the way he or she chooses to present his or her physical self to others (fashion). Throughout the life of an American their age at the time usually determines what activities they choose to be part of. A sixteen year old boy would not choose to spend his Saturday afternoon doing the same thing that a 75 year old grandfather of 6 would spend his afternoon doing. The teenager might decide to play a game of baseball in the park, while the older man might decide to spend the evening with his grandchildren in his garden. Even though both of these people decide to busy themselves differently because of their age they are still Americans. So it is evident that a persons age is descriptive of what a person may choose do with themselves. Yet another description of an American are the priorities that he or she hold dear to them. One person may feel that their family is their greatest priority, however a man with no family would not feel this way. This man might feel that his greatest priority would be taking care of himself. This can also be tied in with age. A younger person might feel that his of her greatest priority is to their friends, but an older person might feel that their most important overall priority is to their children. Whatever a persons priorities may be it is true that many different Americans have many different priorities. Finally, the way a person decides to physically present themselves to others is a major descriptor of an American. Although some Americans care not what others think of their physical appearence, many on the other hand do. A certain high school girl might find pleasure in working an entire

Aristotle’s theory of the Tragic Hero Essay

â€Å"A man doesn’t become a hero until he can see the root of his own downfall† Tragic hero’s who fit under Aristotle’s depiction are known as ‘Aristotelian Tragic Hero’s’ and possess five specific characteristics; 1) A flaw or error of judgment (also known as ‘hamartia’ which is a fatal flaw leading to the downfall of a tragic hero or heroine) 2) A reversal of fortune due to the error of judgment (also known as ‘peripeteia’, which is a sudden reversal of fortune or change in circumstances) 3) The discovery or recognition that the reversal was brought about by the hero’s own actions (Referred to as ‘anagnorisis’, which is a moment in a play when a character makes a critical discovery) 4) Excessive pride (hubris) 5) The character’s fate must be greater than deserved’. In the beginning, the character must be seen as equal morally to normal people in order for the audience to identify with him/her. This identification allows the sentiment of ‘pity’ which is crucial in a tragic play. The Aristotelian tragic hero inevitably suffers a tragic death, having fallen from great heights and made an irreversible mistake. The hero must courageously accept their death with honour. Other common traits of the Aristotelian tragic hero: a) Hero must suffer more than he deserves b) Hero must be doomed from the start, but bears no responsibility for possessing his flaw. c) Hero must be noble in nature, but be imperfect so that the audience can see themselves in him. d) Hero must have discovered his fate by his own actions, not by things happening to him. e) Hero must understand his doom, as well as the fact that his fate was discovered by his own actions. f) Hero’s story should arouse fear and empathy. g) Hero must be physically or spiritually wounded by his experiences, usually resulting in his death. h) The hero must be intelligent so that he may learn from his mistakes. i) The hero must have a weakness, usually, it is pride. j) He must be faced with a very serious decision that he must face. Aristotle identifies tragedy as the most refined version of poetry dealing with lofty matters and comedy as the most refined version of poetry dealing with base matters. He traces a brief and speculative history of tragedy as it evolved from dithyrambic hymns in praise of the god Dionysus. Dithyrambs were sung by a large choir, sometimes featuring a narrator. Aeschylus invented tragedy by bringing a second actor into dialogue with the narrator. Sophocles innovated further by introducing a third actor, and gradually tragedy shifted to its contemporary dramatic form. Aristotle defines tragedy according to seven characteristics: (1) it is mimetic, (2) it is serious, (3) it tells a full story of an appropriate length, (4) it contains rhythm and harmony, (5) rhythm and harmony occur in different combinations in different parts of the tragedy, (6) it is performed rather than narrated, and (7) it arouses feelings of pity and fear and then purges these feelings through catharsis. A tragedy c onsists of six component parts, which are listed here in order from most important to least important: plot, character, thought, diction, melody, and spectacle. A well-formed plot must have a beginning, which is not a necessary consequence of any previous action; a middle, which follows logically from the beginning; and an end, which follows logically from the middle and from which no further action necessarily follows. The plot should be unified, meaning that every element of the plot should tie in to the rest of the plot, leaving no loose ends. This kind of unity allows tragedy to express universal themes powerfully, which makes it superior to history, which can only talk about particular events. Episodic plots are bad because there is no necessity to the sequence of events. The best kind of plot contains surprises, but surprises that, in retrospect, fit logically into the sequence of events. The best kinds of surprises are brought about by peripeteia, or reversal of fortune, and anagnorisis, or discovery. A good plot progresses like a knot that is tied up with increasingly greater complexity until the moment of peripeteia, at which point the knot is gradually untied until it reaches a completely unknotted conclusion. For a tragedy to arouse pity and fear, we must observe a hero who is relatively noble going from happiness to misery as a result of error on the part of the hero. Our pity and fear is aroused most when it is family members who harm one another rather than enemies or  strangers. In the best kind of plot, one character narrowly avoids killing a family member unwittingly thanks to an anagnorisis that reveals the family connection. The hero must have good qualities appropriate to his or her station and should be portrayed realistically and consistently. Since both the character of the hero and the plot must have logical consistency, Aristotle concludes that the untying of the plot must follow as a necessary consequence of the plot and not from stage artifice, like a deus ex machina (a machine used in some plays, in which an actor playing one of the gods was lowered onto the stage at the end). Aristotle discusses thought and diction and then moves on to address epic poetry. Whereas tragedy consists of actions presented in a dramatic form, epic poetry consists of verse presented in a narrative form. Tragedy and epic poetry have many common qualities, most notably the unity of plot and similar subject matter. However, epic poetry can be longer than tragedy, and because it is not performed, it can deal with more fantastic action with a much wider scope. By contrast, tragedy can be more focused and takes advantage of the devices of music and spectacle. Epic poetry and tragedy are also written in different meters. After defending poetry against charges that it deals with improbable or impossible events, Aristotle concludes by weighing tragedy against epic poetry and determining that tragedy is on the whole superior. Aristotle takes a scientific approach to poetry, which bears as many disadvantages as advantages. He studies poetry as he would a natural phenomenon, observing and analyzing first, and only afterward making tentative hypotheses and recommendation s. The scientific approach works best at identifying the objective, lawlike behavior that underlies the phenomena being observed. To this end, Aristotle draws some important general conclusions about the nature of poetry and how it achieves its effects. However, in assuming that there are objective laws underlying poetry, Aristotle fails to appreciate the ways in which art often progresses precisely by overturning the assumed laws of a previous generation. If every play were written in strict accordance with a given set of laws for a long enough time, a revolutionary playwright would be able to achieve powerful effects by consciously violating these laws. In point of fact, Euripides, the last of the three great tragic poets of Ancient Greece, wrote many plays that violated the logical and structured principles of  Aristotle’s Poetics in a conscious effort to depict a world that he saw as neither logical nor structured. Aristotle himself gives mixed reviews to Euripides’ troubling plays, but they are still performed two and a half millennia after they were written. Aristotle’s concept of mimesis helps him to explain what is distinctive about our experience of art. Poetry is mimetic, meaning that it invites us to imagine its subject matter as real while acknowledging that it is in fact fictional. When Aristotle contrasts poetry with philosophy, his point is not so much that poetry is mimetic because it portrays what is real while philosophy is nonmimetic because it portrays only ideas. Rather, the point is that the ideas discussed in philosophical texts are as real as any ideas ever are. When we see an actor playing Oedipus, this actor is clearly a substitute through which we can imagine what a real Oedipus might be like. When we read Aristotle’s ideas on art, we are in direct contact with the ideas, and there is nothing more real to imagine. Art presents reality at one level of remove, allowing us a certain detachment. We do not call the police when we see Hamlet kill Polonius because we know that we are not seeing a real event but only two actors imitating real-world possibilities. Because we are conscious of the mimesis involved in art, we are detached enough that we can reflect on what we are experiencing and so learn from it. Witnessing a murder in real life is emotionally scarring. Witnessing a murder on stage gives us a chance to reflect on the nature and causes of human violence so that we can lead a more reflective and sensitive life. Aristotle identifies catharsis as the distinctive experience of art, though it is not clear whether he means that catharsis is the purpose of art or simply an effect. The Greek word katharsis originally means purging or purification and refers also to the induction of vomiting by a doctor to rid the body of impurities. Aristotle uses the term metaphorically to refer to the release of the emotions of pity and fear built up in a dramatic performance. Because dramatic performances end, whereas life goes on, we can let go of the tension that builds during a dramatic performance in a way that we often cannot let go of the tension that builds up over the course of our lives. Because we can let go of it, the emotional intensity of art deepens us, whereas emotional intensity in life often just hardens us. However, if this process of catharsis that allows us to experience powerful emotions and then  let them go is the ultimate purpose of art, then art becomes the equivalent of therapy. If we define catharsis as the purpose of art, we have failed to define art in a way that explains why it is still necessary in an era of psychiatry. A more generous reading of Aristotle might interpret catharsis as a means to a less easily defined end, which involves a deeper capacity for feeling and compassion, a deeper awareness of what our humanity consists in. Aristotle insists on the primacy of plot because the plot is ultimately what we can learn from in a piece of art. The word we translate as â€Å"plot† is the Greek wordmuthos, which is the root for myth. Muthos is a more general term than plot, as it can apply to any art form, including music or sculpture. The muthos of a piece of art is its general structure and organization, the form according to which the themes and ideas in the piece of art make themselves apparent. The plot of a story, as the term is used in the Poetics, is not the sequence of events so much as the logical relationships that exist between events. For Aristotle, the tighter the logical relationships between events, the better the plot. Oedipus Rex is a powerful tragedy precisely because we can see the logical inevitability with which the events in the story fall together. The logical relationships between events in a story help us to perceive logical relationships between the events in our own lives. In essence, tragedy shows us patterns in human experience that we can then use to make sense of our own experience.

Personal Narrative A Haunted House - 1859 Words

For my final project, I visited to a haunted house to experience how American people are spending the most famous holiday Halloween night with my friends. My methodology is ethnographic observation which to visit a haunted house and experience one of many â€Å"American ritual† during Halloween season. As I am going to break ethnocentrism, practice viewing and adventuring American culture. Ethnocentrism is getting out of my comfort zone, experiencing other culture. I am going to a haunted house to see why the American people are enjoying getting scared also why people are coming back for it. Nightmare on 9 is one of the scariest haunted house in Washington state; people are rating this haunted house ten skulls out of nine. I am exceedingly excited and ready to spend a night at Nightmare on 9 with my friends on October 29th. When I first came to America, with my host family I went to trick-or-treating with friends and host family’s daughter. I still remember that I dressed up and had full make-up as Dracula, and my friends dressed up as ghosts. I could not imagine that people can receive a year’s candy in one day. Also, I have picked up a pumpkin in a pumpkin farm and brought home carving many jack-o’-lanterns decorating at the front door with a candle inside of the pumpkin Therefore, Halloween is one of my favorite holidays, but I could not go trick-or-treating anymore because I am an adult now. Therefore, I was terribly disappointed about that I could not celebrate HalloweenShow MoreRelatedPersonal Narrative Essay : The Experience Of A Haunted House999 Words   |  4 PagesOn October 28th I ignored my nerves and saw the haunted house put on by my fellow Waldorf students. I brought my boyfriend with me because I am too much of a scaredy-cat to go on my own. I truly am a baby when i t comes to â€Å"scary† things; I hate watching scary movies or going to haunted houses. I have anxiety, and these types of things cause my anxiety to be extremely high. If I am being completely honest, my only motivation for going was to get the event for this class, since I have to miss otherRead MoreThe Repression of Women in Victorian Society as Shown in 19th Century Literature843 Words   |  4 Pagesimage, showing them as gentle, loyal and angelic. They were rejected of any personal opinions or independence, for these were only a man’s privilege. Class and status also affected women of the era. Evidence for these and further repressions can be found in the short stories of 19th century writers. Charlotte Perkins Gilman wrote ‘The Yellow Wallpaper’, which relates partially to her own personal experiences as a woman under her husbands overwhelming influence. CharlesRead MoreBeloved : A Reconstruction Of Our Past1705 Words   |  7 PagesOsagie discusses Morrison’s narrative as a product in â€Å"historical mythmaking† in her review Is Morrison Also Among the Prophets?: â€Å"Psychoanalytic† Strategies in Beloved. She incorporates Du Bois’s idea of â€Å"double consciousness†, the divided identity of African Americans as the way they see themselves and the way society sees them, as a strategy Morrison incorporates to re-narrate the history of slavery (Osagie). Through this double consciousness, Morrison creates a new narrative of what slavery means toRead MoreArgumentative Essay On The Fall Of The House Of Usher1169 Words   |  5 PagesArgumentary the most famous work of Poe is The Fall of the House of Usher(The House of Usher), as the short story incorporates every trope of modern horror, important among these is the setting. A nameless narrator receives a letter f rom his boyhood friend, Roderick Usher, asking the narrator to visit. The narrator goes, and finds his friend in bad mental condition with his sister’s health failing. When his sister dies, they bury her in the house. After this act, the boyhood friends are in more troubleRead MoreAnalysis Of The Narrative By Ayub Suleiman Diallo1435 Words   |  6 Pageswill focus on the issues of slave trade and slavery, and the following experts of personal narratives will be used. Firstly, the paper will analyze the personal narrative by John Barbot in which he describes the state of slavery in Africa. Secondly, there will be the analysis of the narrative by Ayub Suleiman Diallo, in which he recall how he was captured and taken to slavery. Thirdly, the paper will use the narrative by young Olaudah Equiano, who remembers how he was kidnapped into slavery. LastlyRead More Madness in The Yellow Wallpaper and The Tell-Tale Heart1679 Words   |  7 Pagesdifferent intervals: We have been he re two weeks, and I havent felt like writing before, since that first day. It is an account of the characters most personal emotions during the period of time. She confides in her diary and uses it to justify and explain her often irrational behaviour. The Tell-Tale Heart is written in a narrative style where you can clearly hear the character speaking. It is written as if the character was speaking to a psychiatrist or a detective giving a full accountRead MoreThe Presentation of Isolation in Jane Eyre and the Wide Sargasso Sea1546 Words   |  7 Pagesmethods such as violence and pleading to escape her separation. In The Wide Sargasso Sea, Annette and her family inhabit an isolated residence, and subsequently, due to their location, also face separation from society, much like in Jane Eyre. The house owned by Antoinette’s mother is rarely visited, Antoinette is aware of this blatant lack of interaction with other individuals as she asked ‘why so few people came to see us’, suggesting their isolation was severe enough to indicate, even to a childRead MoreWuthering Heights A New Gothic875 Words   |  4 Pagesgothic elements in her narrative and makes some of these elements inexplicit wither it is a dream or a supernatural event. She introduces the idea of psychological fears that make a person to imagine or hallucinate about things may does not exist. The most vivid incident t hat explains Bronte’s situation is Mr. Lockwood staying at the estate of Wuthering Heights. One night, Lockwood is forced to stay at Wuthering Heights because of the snowstorm. He is unable to return to his house, so he stays that terrifiedRead MoreJane Eyre By Charlotte Bronte1374 Words   |  6 Pagesis to open the fiction to the realm of the irrational and perverse narratives, obsessions, and nightmarish terrors that hide beneath the literally civilized mindset in order to demonstrate the presence of the uncanny existing in the world known rationally through experience. At certain points, the interactions between the conventions of the Gothic fictions with other thematic, ideological, and/or symbolic functions of the narrative would rather be challenging. However, though the analysis of JaneRead MoreA Post War Society Through Landscapes Of Memory And Oblivion1646 Words   |  7 Pagesexclusion (Bhabha 1994: 1) This paper tries to understand how a national narrative is construed in a post war society through landscapes of memory and oblivion. The analysis interrogates claims of past, present and future that fashion the landscape and the resulting ambivalences in interpreting identities. RomeshGunasekara’s short story collection Noontide Toll interweaves the story of the war distraught island through the narrative of Vasantha – ‘the van man’. Stories concerning ‘yearnings of teenagers