Sunday, August 23, 2020
Friday, August 21, 2020
The Negative Effects of Fossil Fuel Usage Essay example -- Environmen
The Negative Effects of Fossil Fuel Usage    The soundness of the earth is our livelihood.â When the earth isn't healthy it could prompt medical issues on an individual level.â One of the major ecological issues is air contamination from the consuming of non-renewable energy sources.  Levels of carbon dioxide radiated by petroleum derivatives into the environment in 1991 was an expected â€Å"5.6 billion tons for every year†(Tesar, 28).â If we hold running down the way we are on utilizing non-renewable energy sources like no tomorrow there is some concern among researchers, â€Å"Some researchers gauge that the number will hop to as much as 30 billion tons for every year inside the following not many decades†(28).   Concern for the earth is anything but an ongoing phenomena.â Rachel Carson (1907-1964), was a â€Å"American sea life scientist and the writer of generally read books on natural themes†â (Bram, 326).â One of her increasingly exceptional statements on the earth is, â€Å"The generally disturbing of all man’s attacks upon the earth is the defilement of air, earth, streams, and sea†¦this contamination is generally irrecoverable†(Peter, 171).  I concur with Rachel Carson that earth, air, and water contamination is generally irrecoverable.â â Some establishments stirring today to tidy up the earth do support a few, however as I see it they are not demonstrating results.â There endeavors are a weak endeavor since contamination levels continue rising and they would never keep up.â According to Hayes the previous chief of the Solar Research Institute under President Jimmy Carter of Earth Island Journal, â€Å"In 1993, President Clinton promised to lessen US CO2 outflows to 1990 levels constantly 2000.â Instead, the nation’s CO2 discharges are currently anticipated to ascend in any event 13 percent by the ... ...> Selling, Stephen.â A Brief History of Time:â From the Big Bang to Black Holes.  New York:â Bantam, 1988. Diminish, Laurence J. Dr.â Peter’s Quotations.â New York:â Quill William Morrow, 1977. Simanek, Donald E.â (1994)â The Hazards of Solar Energy.â  Dsimanek/solar.htm>â (27 October 1998). â€Å"Solar Power-The Basics.†â Solar Power-The Basics.â 27 October 1998.  http://www.greenpeace.org.uk/sun oriented/brief2.htmlâ (27 October 1998). â€Å"Solar Tax Credits for North Carolina.†â North Carolina Solar Center Information  Factsheet. 30 November 1998.â  (30 November 1998). Tesar, Jenny.â Global Warming.â New York;â Facts On File, 1991. â€Å"Timeline: Photovoltaic Development.†â Untitled.â 2 December, 1998.   (2 December, 1998). Â
Monday, July 13, 2020
Khan Academy students make it work in new documentary series
Khan Academy students make it work in new documentary series At Phillips Magnet Elementary School in Napa, California, where 65% of students are second-language learners and 85% come from low-income backgrounds, one group of students is bringing light to a community no longer willing to stay in the shadows.Watch the trailer:The new docuseries ‘Make it Work’, now available on Amazon Prime Video and The Roku Channel, features students who are inspired by their teacher and powered by lessons from Khan Academy. Follow their journey as they apply newfound skills to propose a public improvement project to make the streets around their school safer.“I’m so proud of these students,†says Sal Khan, Khan Academy’s founder. “Their success shows us how students who have access to a high-quality education are able to unlock their full potential and accomplish great things. I want that for every child in America and around the world.†Narrated by YouTube icon Hank Green and produced and directed by Emmy Award-winning filmmakers Kip and Kern Konwiserâ€"‘Miss Evers’ Boys’ and ‘On Hallowed Ground’â€"the four-part series follows young disruptors as they use imagination and innovation to improve their communities.
Wednesday, May 20, 2020
Advanced French Past Tenses and Imperfect
The difference between the two main French past tenses, the passà © composà © and the imperfect, is a constant struggle for many French students. In my lesson on passà © composà © vs imperfect, you learned about the fundamental differences between these two tenses. In this more advanced lesson, you will learn about the particularities of certain verbs when used in the past. Usually Imperfect Some French verbs are nearly always used in the imperfect rather than the passà © composà ©: aimer - to like, lovecroire - to believeespà ©rer - to hopeà ªtre - to bepenser - to thinksembler - to seemsentir - to feelvouloir - to want These verbs describe a state of mind or state of being. They are most often in the imperfect because verbs like wanting and being do not usually have a clear indicator of start and finish - either they last for an unspecified amount of time or they are interrupted by some other action.   Jaimais danser quand jà ©tais jeune.   I liked to dance when I was young.   Je croyais en Dieu.   I believed in God.   Jespà ©rais gagner.   I hoped (was hoping) to win.   Jà ©tais heureux lannà ©e passà ©e.   I was happy last year.   Je pensais à mon frà ¨re.   I was thinking about my brother.   Il semblait trop parfait.   It seemed too perfect.   Je me sentais malade pendant toute la journà ©e.   I felt sick all day.   Je voulais rentrer aprà ¨s le film.   I wanted to go home after the movie.However, these verbs are used in the passà © composà © when there is a clear indication of the beginning or end of the action of the verb, or when it is obvious that this was a simple action that only occurred once.   Je nai pas aimà © le film.   I didnt like the movie.   Je ne tai pas cru quand tu as dit...   I didnt believe you when you said...   Hier, jai espà ©rà © que tu viendrais ; aujourdhui, à §a mest à ©gal.   Yesterday I hoped you would come; today I dont care.   Quand je lai vu, jai à ©tà © surpris.   When I saw him, I was surprised (just at that moment).   Jai pensà © à une bonne histoire.   I thought of a good story.   Il a semblà © disparaà ®tre.   He seemed to disappear (all of a sudden).   Jai senti une goutte de pluie.   I felt a drop of rain.   Tout dun coup, jai voulu partir.   All of a sudden, I wanted to leave.Now that you know which verbs are usually in the i mperfect, you can learn about verbs that have different meanings depending on whether they are used in the passà © composà ©Ã‚ or imperfect, and verbal constructions that are always in the imperfect. Meaning Changes There are a few verbs that have different meanings depending on whether they are used in the passà © composà © or imperfect. Note however that these verbs are usually used in the imperfect; the passà © composà © meaning is fairly uncommon.avoir - to have   imperfect - had   Javais de largent. - I had some money   Je navais pas assez de temps. - I didnt have enough time   Javais faim. - I was hungry   passà © composà © - had, got, received   Jai eu un accident. - I had / got into an accident   Jai eu une bonne surprise. - I got a nice surprise   Jai eu faim. - I got hungryconnaà ®tre - to know   imperfect - knew, was familiar with   Je la connaissais bien. - I knew her well   passà © composà © - met   Jai connu Michel hier. - I met Michel (for the first time) yesterdaydevoir - to have to   imperfect - was supposed to (whether I did or not)   Je devais partir à midi. - I was supposed to leave at noon   passà © composà © - must have, had to   Jai dà » le perdre. - I must have lost it   Jai dà » partir à midi. - I had to leave at noon (and did)pouvoir - to be able to   imperfect - could, was able to (whether I did or not)   Je pouvais mentir. - I could lie / was capable of lying   passà © composà © - could, was able to, managed to; (negative) couldnt, was unable to   Jai pu mentir. - I was able to lie   Je nai pas pu mentir. - I couldnt / was unable to liesavoir - to know   imperfect - knew   Je savais ladresse. - I knew the address   Je savais nager. - I knew how to swim   passà © composà © - learned, found out   Jai su la solution. - I found out / discovered the solution   Jai su nager. - I learned how to swimvouloir - to want   imperfect - wanted   Je voulais partir. - I wanted to leave   Je voulais plus dargent. - I wanted more money   passà © composà © - tried, decided to; (negative) refused   Jai voulu partir. - I tried / decided to leave   Je nai pas voulu partir. - I refused to leave Verbal Constructions Some verbs have particular constructions which, when referring to the past, are always in the imperfect:aller infinitive (near future)   Jallais à ©tudier. - I was going to study.avoir (with age)   Javais 18 ans. - I was 18.à ªtre en train de   Jà ©tais en train dà ©crire une lettre. - I was writing a letter.faire (with weather)   Il faisait beau. - It was nice out.venir de infinitive (recent past)   Je venais darriver. - I had just arrived.
Wednesday, May 6, 2020
The Physics of Piano - 1027 Words
One of the most common musical instruments in many homes is the piano; and most people have the opportunity for even a few lessons in their youth. However, despite the simplicity of its lines and keys (88 keys), 2-3 pedals on the modern piano, and either upright (vertical) or grand style (horizontal), the physics of the piano are both interesting and complex. The modern piano is a descendent of the harpsichord, which used a plucking technique much like that of plucking the strings of a harp or lute. Bartolomeo Crisotofori, an Italian craftsman, substituted felt hammers in place of the plucking mechanism, making the instrument capable of graduations of tone and timber. He called his new instrument the Gravicembalo col piano e forte (a harpsichord with louds and softs). This was later shortened to the piano and with critiques from Baroque composers like Bach, a number of improvements were made to sound quality and tonality eventually emerging as the preferred keyboard instrument for Mo zart, Haydn, and Beethoven. Over the course of centuries to different piano types have emerged. The grand piano, from 5 6 to 8 or 9 in length horizontal to the upright piano, more suitable for the home, which also exists in differing sizes, 3-5; in height (Parakilas). The mechanism of a piano consists of pressing on a key (either black or white) on the keyboard causing a felt-covered hammer to strike steel strings that are various lengths and tensions. The hammers rebound; allowing theShow MoreRelatedThe Greatest Thinker Of The 20th Century1655 Words  | 7 PagesEinstein Albert Abraham Einstein. It is a name we all know, the name of, perhaps, the greatest thinker of the 20th century. 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The first being my mathematics and physics teachers, both engineers by qualification, who have helped me enhance the fundamental skills essential for engineering and embrace the importance of the field. The second being learning about uses of technology in computer science, it taught me the magnitude which technology contributes to our lives and has resulted in my desire to improve the lives of others. I believe that my mathematics and physics skills would make me a proficient engineer.Read MoreBlowing Bottle Tops: Making Music with Glass Bottles716 Words  | 3 Pagespaper will explain how this works. The paper will be talking about sound, sound waves, standing waves, musical note names and frequencies, resonance, and closed-end air columns. Closed-end air columns will be a main focus in the paper, studying the physics behind it. Glass bottles are an example of a closed-end air column. Therefore, the more water inside the bottle, the lower the note, and less water would be a higher note. Closed-end air can be many things; ranging from brass instruments, woodwindRead MoreThe Spot Of The Corner1613 Words  | 7 Pagesstarting high school and she wanted to have piano lessons; she was really talented and even before having any lesson she could play some tunes by ear. For this reason, my parents decided to buy a piano for her, and they saw that there was some space available next to the old bookshelf; so, they decided to place the piano there. My favorite place suddenly changed. I no longer felt so free, as before, to see the beautiful picture, because now it was above the piano and my sister used to practice their assignmentsRead MoreThe Life of Albert Einstein837 Words  | 4 PagesEinstein had a sister named Maja (pronounced Maya) who was born two years after him. (â€Å"Albert Einstein†) He also had a cousin named Elsa Là ¶wenthal, whom he married later. Einstein mother, Pauline, was a talented musician and introduced her son to the piano when he was a small boy, she encouraged his passion for the violin. He played the violin from age 6 to 13. When he was five Albert Einstein became engrossed with a compass. He was mystified that invisible forces could deflect the needle. When EinsteinRead MoreNsm Essay1166 Words  | 5 Pagesactivities. I am taking five APs this year, each of which gives about an hour of work to do in the evening and on weekends. In addition to school work, I’ve been playing the piano for 9 years and clarinet for over 4 years, and I practice both instruments every day. School band didn’t fit into my schedule in high school, but, luckily, my piano teacher directs a jazz band which meets weekly. The band, called BIOMY, has middle schoolers, high schoolers, and even a couple of adults. We perform at places from
Solar Energy Free Essays
A new solar powered adsorption refrigerator with high performance Meunier published a comparison of those three sorption systems for solar cooling (Meunier, 1994). The solid-gas system used in the present study is adsorption. The solar adsorption refrigerators have been developed mainly to be used in hot regions with no electricity supply. We will write a custom essay sample on Solar Energy or any similar topic only for you Order Now There is an urgent need in the health sector (for the conservation of medicines and vaccines). These systems have the advantage of not requiring any energy other than solar energy. Regarding performance, the highest values of COPSR (0. 10-0. 12) were obtained with the adsorption systems zeolite + water (Grenier et al. , 1988) and activated carbon + methanol (Boubakri et al. , 1992a,b; Pons and Grenier, 1987). As methanol can easily evaporate at temperatures below O oc, thus favouring the production of ice, the most environmentally friendly refrigerant must be water. Using water, ice can be produced within the evaporator, acting as a ‘cold storage’. Both refrigerants, water or methanol, operate at below atmospheric pressure and therefore require vacuum technology. The main urpose of the present study is to obtain what is, technically speaking, a simple machine. This aim seems reasonably achievable with an adsorptive machine, operated in a 100% solar-powered 24 h cycle with a flat-plate solar collector containing the adsorbent. However, when referring to the work reported above, both the efficiency of the solar collector and that of the adsorption thermodynamic cycle could be improved. These requirements were crucial to the design of the ‘advanced’ machine. The laboratory of solar energy of the Engineering school of the Canton de Vaud (EIVD, Yverdon-lesBains, Switzerland) has been eveloping adsorptive solar refrigerators since 1999. The first systems built used the adsorption pair of activated carbon + methanol. For reasons of reliability and respect for the environment, this pair has been abandoned in favour of a silicagel + water pair. The prototype described and analyzed in this paper has been functioning since the summer of 2000 on the site of the EIVD. A thorough measurement system allows us to characterise it in a complete way. During the summer of 2001, a constant procedure of thermal load in the cold cabinet allowed us to observe the behaviour of the adsorption system over a continuous period of 68 ays. We have highlighted the great influence of both external temperature and daily irradiation upon the daily coefficient of performance (COPSR ). Previously, few articles were interested in the analysis of the storage. 2. Description of adsorption and of the adsorption cooling cycle Adsorption, also known as physisorption, is the process by which molecules of a fluid are fixed on the walls of a solid material. The adsorbed molecules undergo no chemical reaction but simply lose energy when being fixed: adsorption, the phase change from fluid to adsorbate (adsorbed phase) is exothermic. Moreover this process is reversible. In the following, we will focus on adsorption systems mainly used in cooling (or heatpumping) machines: a pure refrigerant vapour that can easily be condensed at ambient temperature and a microporous adsorbent with a large adsorption capacity. The main components of an adsorptive cooling machine are the adsorber (in the present case, the solar collector itself), the condenser, the evaporator and a throttling valve between the last two devices, see Fig. 2. An ideal cycle is presented in the D‚ ¬hring diagram (LnP vs. †¦I=T), Fig. 1. 2001). We can summarize it in four stages. C. Hildbrand et al. / solar Energy 77 (2004) 311-318 13 Fig. 1 . An ideal adsorption cooling cycle in the D‚ ¬ hring diau gram. Saturation liquid- vapour curve for the refrigerant (EC dashed line), isoster curves (thin lines), adsorption cycle (thick lines). Heating period: step AB (7 a. m. fl 10 a. m. ) and step BD (10 a. m. fl 4 p. m. ); cooling period: step DF (4 p. m. fl 7 p. m. ) and step FA(7 p. m. fl 7 a. m. ). Step 1: isosteric heating  ¶A ! BD. The system temperature and pressure increase due to solar irradiance. Step 2: desorption + condensation dB ! DD. Desorption of the water steam contained in the silicagel; condensation of the water steam in the ondenser; the water in the evaporator is drained through the valve. Step 3: isosteric cooling ?D ! FP. Decrease of the period of sunshine; cooling of the adsorber; decrease of the pressure and the temperature in the system. Step 4: adsorption + evaporation  ¶F ! AD. Evaporation of water contained in the evaporator; cooling of the cold cabinet; production of ice in the evaporator; readsorption of water steam by the silicagel. 3. Description of the machine tested in Yverdon-les-Bains, Switzerland Adsorptive pair. The refrigerant is water, and the adsorbent is a microporous silicagel (Actigel SG ¤ , Silgelac). Collector-adsorber. The solar collector (2 m2 , tilt angle of 300) is double-glazed: a Teflon ¤ film is installed between the glass and the adsorber itself. The adsorber consists of 12 parallel tubes (72. 5 mm in diameter) that contain the silicagel (78. 8 kg). The tubes are covered with an electrolytic selective layer (Chrome-black, Energie Solaire SA), which absorbs 95% of the visible solar radiation while presenting an emissivity of 0. 07 in the infrared wave-lengths. A valve located between the graduated tank and the evaporator is needed on this machine. For control strategy reasons, this valve is electrically powered. 4. 5. Ventilation damper management Closing: when the irradiance goes above 100 W/m2 . Opening: at the end of the afternoon when the angle of the solar beam radiation incident upon the aperture plane of collector (angle of incidence) is above 500. 4. Measurements and operations The objective of the 2001 series of measurements was to obtain a high number of measurements continuously, in order to characterise he working of our adsorption machine. To do this, a system of measurement and a constant procedure of load has been established. 4. 1. Measurements The temperature is measured (probes Pt100) in the silicagel of a central tube of the collector-adsorber (7 sensors), on two condenser tubes and three evaporator tubes; and the ambient air temperature is also measured. The vapour pressure is measured by a piezogauge in the collector-adsorber, in the condenser and in the evaporator. The global irradiance in the plane of the collector is recorded by a pyranometer. A graduated tank (6. 5 1) collects the condensed water. The level of liquid water is automatically measured by a level detector. The series of measurements took place from July 25th to September 30th 2001 (68 days) in Yverdon-lesBains (altitude: 433 m, longitude: )6. 380, latitude: 46. 470). Fig. 3 shows the observed weather conditions (daily irradiation and mean external temperature). This graph shows two different periods: (1) From July 25th to the beginning of September: during this summer period, the mean external temperature is above 20 oc and the mean daily irradiation reaches 22 MJ/m2 . This fine weather period is interrupted between the 3rd and 9th August by ess favourable weather. (2) From the beginning of September to the end of the measurement: the mean external temperature and the daily irradiation are distinctly lower (13 oc and 13 MJ/m2 ). Furthermore, the conditions are very variable from one day to the next. 4. 2. Acquisition system and command 6. Performance of the tested unit A Labview ¤ program takes measurements and administers various commands (valve, dampers and load). A measurement is made every 30 s. How to cite Solar Energy, Papers
Thursday, April 23, 2020
Walt Whitman was born on May 31, 1819 in New Yo Essays - Come Again
Walt Whitman was born on May 31, 1819 in New York. During the Civil War Walt Whitman worked as a volunteer nurse. He believed that slavery was wrong, that women should be able to own property, that there should be labor laws, and many other basic human rights that were considered controversial and radical back in the day. Whitman was a humanist, which is a philosophy that affirms that humans have the right and responsibility to give meaning and shape to their own lives. Walt Whitman married a Dutch woman named Louisa Van Velsor. He died March 26, 1892 in New Jersey. Beautiful Women - WOMEN sit, or move to and frosome old, some young; The young are beautifulbut the old are more beautiful than the young. A Clear Midnight - THIS is thy hour O Soul, thy free flight into the wordless, Away from books, away from art, the day erased, the lesson done, Thee fully forth emerging, silent, gazing, pondering the themes thou lovest best. Night, sleep, and the stars. A Glimpse - A GLIMPSE, through an interstice caught, Of a crowd of workmen and drivers in a bar-room, around the stove, late of a winter nightAnd I unremark'd seated in a corner; Of a youth who loves me, and whom I love, silently approaching, and seating himself near, that he may hold me by the hand; A long while, amid the noises of coming and goingof drinking and oath and smutty jest, There we two, content, happy in being together, speaking little, perhaps not a word. Thought - OF EqualityAs if it harm'd me, giving others the same chances and rights as myselfAs if it were not indispensable to my own rights that others possess the same. Bathed In War's Perfume - BATHED in war's perfumedelicate flag! (Should the days needing armies, needing fleets, come again,) O to hear you call the sailors and the soldiers! flag like a beautiful woman! O to hear the tramp, tramp, of a million answering men! O the ships they arm with joy! O to see you leap and beckon from the tall masts of ships! O to see you peering down on the sailors on the decks! Flag like the eyes of women. I Dream'd in a Dream - I DREAM'D in a dream, I saw a city invincible to the attacks of the whole of the rest of the earth; I dream'd that was the new City of Friends; Nothing was greater there than the quality of robust loveit led the rest; It was seen every hour in the actions of the men of that city, And in all their looks and words. On the Beach at Night - On the beach at night, Stands a child with her father, Watching the east, the autumn sky. Up through the darkness, While ravening clouds, the burial clouds, in black masses spreading, Lower sullen and fast athwart and down the sky, Amid a transparent clear belt of ether yet left in the east, Ascends large and calm the lord-star Jupiter, And nigh at hand, only a very little above, Swim the delicate sisters the Pleiades. From the beach the child holding the hand of her father, Those burial-clouds that lower victorious soon to devour all, Watching, silently weeps. Weep not, child, Weep not, my darling, With these kisses let me remove your tears, The ravening clouds shall not long be victorious, They shall not long possess the sky, they devour the stars only in apparition, Jupiter shall emerge, be patient, watch again another night, the Pleiades shall emerge, They are immortal, all those stars both silvery and golden shall shine out again, The great stars and the little ones shall shine out again, they endure, The vast immortal suns and the long-enduring pensive moons shall again shine. Then dearest child mournest thou only for jupiter? Considerest thou alone the burial of the stars? Something there is, (With my lips soothing thee, adding I whisper, I give thee the first suggestion, the problem and indirection), Something there is more immortal even than the stars, (Many the burials, many the days and nights, passing away), Something that shall endure longer even than lustrous Jupiter Longer than sun or any revolving satellite, Or the radiant sisters the Pleiades. Whoever You Are Holding Me Now in Hand - Whoever you are holding me now in hand, Without one thing all will be useless, I give you fair warning before you attempt me
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