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"Symbol of a heater-coil or heating element Some other symbols used for heater- coils or heating elements A heating element converts electrical energy into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element. Unlike the Peltier effect, this process is independent of the direction of current. Heating elements types Tubular electric heater A folded tubular heating element from an espresso machine A coiled heating element from an electric toaster Metal Resistance wire: Metallic resistance heating elements may be wire or ribbon, straight or coiled. They are used in common heating devices like toasters and hair dryers, furnaces for industrial heating, floor heating, roof heating, pathway heating to melt snow, dryers, etc. The most common classes of materials used include: * Nichrome: Most resistance wire heating elements use nichrome 80/20 (80% nickel, 20% chromium) wire, ribbon, or strip. Nichrome 80/20 is an ideal material, because it has relatively high resistance and forms an adherent layer of chromium oxide when it is heated for the first time. Material beneath this layer will not oxidize, preventing the wire from breaking or burning out. * Kanthal (FeCrAl) wires * Cupronickel (CuNi) alloys for low temperature heating * Etched foil: Etched foil elements are generally made from the same alloys as resistance wire elements, but are produced with a subtractive photo-etching process that starts with a continuous sheet of metal foil and ends with a complex resistance pattern. These elements are commonly found in precision heating applications like medical diagnostics and aerospace. Ceramic and semiconductor * Molybdenum disilicide (MoSi2) an intermetallic compound, a silicide of molybdenum, is a refractory ceramic primarily used in heating elements. It has moderate density, melting point 2030 °C (3686 °F) and is electrically conductive. At high temperatures it forms a passivation layer of silicon dioxide, protecting it from further oxidation. The application area includes glass industry, ceramic sintering, heat treatment furnaces and semiconductor diffusion furnaces. * Silicon carbide, see silicon carbide § heating elements * Silicon nitride, see silicon nitride in automotive industry. New generation hot surface igniter for gas furnace and diesel engine glow plug are made of silicon nitride material. Such heating element or glow plug reach a maximum temperature of 1400 °C and are quick to ignite gas, diesel or kerosene. https://plug.fkk- corporation.com/en/products/sin-ceramic-igniter * PTC ceramic elements: PTC ceramic materials are named for their positive thermal coefficient of resistance (i.e., resistance increases upon heating). While most ceramics have a negative coefficient, these materials (often barium titanate and lead titanate composites) have a highly nonlinear thermal response, so that above a composition-dependent threshold temperature their resistance increases rapidly. This behavior causes the material to act as its own thermostat, since current passes when it is cool, and does not when it is hot. Thin films of this material are used in automotive rear-window defrost heaters, and honeycomb-shaped elements are used in more expensive hair dryers , space heaters and most modern pellet stove.Such heating element can reach a temperature of 950-1000 °C and are praised for the speed of temperature and stability.https://plug.fkk-corporation.com/en/products/pellet-ceramic-igniter * Quartz halogen heaters are also used to provide Radiant heating and cooling. Thick film heaters A thick film heater printed on a mica sheet. Thick film heaters are a type of resistive heater that can be printed on a thin substrate. Thick film heaters exhibit various advantages over the conventional metal-sheathed resistance elements. In general, thick film elements are characterized by their low profile form factor, improved temperature uniformity, quick thermal response due to low thermal mass, low energy consumption, high watt density and wide range of voltage compatibility. Typically, thick film heaters are printed on flat substrates, as well as on tubes in different heater patterns. These heaters can attain watt densities of as high as 100 W/cm2 depending on the heat transfer conditions. The thick film heater patterns are highly customizable based on the sheet resistance of the printed resistor paste. These heaters can be printed on a variety of substrates including metal, ceramic, glass, polymer using metal/alloy-loaded thick film pastes. The most common substrates used to print thick film heaters are aluminum 6061-T6, stainless steel and muscovite or phlogopite mica sheets. The applications and operational characteristics of these heaters vary widely based on the chosen substrate materials. This is primarily attributed to the thermal characteristics of the heater substrate. There are several conventional applications of thick film heaters. They can be used in griddles, waffle irons, stove-top electric heating, humidifiers, tea kettles, heat sealing devices, water heaters, iron and cloth steamers, hair straighteners, boilers, 3D printer heated beds, thermal print heads, glue guns, laboratory heating equipment, clothes dryers, baseboard heaters, deicing, or defogging devices, warming trays, car side mirrors, fridge defrosting, heat exchangers, etc. For most applications, the thermal performance and temperature distribution are the two key design parameters. In order to avoid any hotspots and to maintain a uniform temperature distribution across a substrate, the circuit design can be optimized by changing the localized power density of the resistor circuit. An optimized heater design helps to control the heater output and modulate the local temperatures across the heater substrate. In cases where there is a requirement of 2 or more heating zones with different output power over a relatively small area, a thick film heater can be designed to achieve a zonal heating pattern on a single substrate. Thick film heaters can largely be characterized under two subcategories- negative temperature coefficient (NTC) or positive temperature coefficient (PTC) based on the effect of temperature increase on the element's resistance. The NTC type heaters are characterized by a decrease in resistance as the heater temperature increases and thus have a higher output power at higher temperatures for a given input voltage. The PTC heaters behave in an opposite manner with an increase of resistance and decreasing heater power at elevated temperatures. This characteristic of the PTC heaters make them self regulating too, as their output power saturates at a fixed temperature. On the other hand, NTC type heaters generally require a thermostat or a thermocouple in order to control the heater runaway. These heaters are used in applications which require a quick ramp-up of heater temperature to a predetermined set- point as they are usually faster acting than the PTC type heaters. Thick film heater printed on a metal substrate Polymer PTC heating elements A flexible PTC heater made of conductive rubber Resistive heaters can be made of conducting PTC rubber materials where the resistivity increases exponentially with increasing temperature. Such a heater will produce high power when it is cold, and rapidly heat up itself to a constant temperature. Due to the exponentially increasing resistivity, the heater can never heat itself to warmer than this temperature. Above this temperature, the rubber acts as an electrical insulator. The temperature can be chosen during the production of the rubber. Typical temperatures are between . It is a point-wise self- regulating heater and self-limiting heater. Self-regulating means that every point of the heater independently keeps a constant temperature without the need of regulating electronics. Self-limiting means that the heater can never exceed a certain temperature in any point and requires no overheat protection. Liquid Electrode_boiler Composite heating elements Tubular Oven Heating Element * Tubular (sheathed) elements normally comprise a fine coil of nichrome (NiCr) resistance heating alloy wire, that is located in a metallic tube (of copper or stainless steel alloys such as Incoloy) and insulated by magnesium oxide powder. To keep moisture out of the hygroscopic insulator, the ends are equipped with beads of insulating material such as ceramic or silicone rubber, or a combination of both. The tube is drawn through a die to compress the powder and maximize heat transmission. These can be a straight rod (as in toaster ovens) or bent to a shape to span an area to be heated (such as in electric stoves, ovens, and coffee makers). * Screen-printed metal–ceramic tracks deposited on ceramic insulated metal (generally steel) plates have found widespread application as elements in kettles and other domestic appliances since the mid-1990s. * Radiative heating elements (heat lamps): A high-powered incandescent lamp usually run at less than maximum power to radiate mostly infrared instead of visible light. These are usually found in radiant space heaters and food warmers, taking either a long, tubular form or an R40 reflector-lamp form. The reflector lamp style is often tinted red to minimize the visible light produced; the tubular form comes in different formats: ** Gold coated - Made famous by the patented Phillips Helen lamp. A gold dichroic film is deposited on the inside that reduces the visible light and allows most of the short and medium wave infrared through. Mainly for heating people. A number of manufacturers now manufacture these lamps and they improve constantly. ** Ruby coated - Same function as the gold-coated lamps, but at a fraction of the cost. The visible glare is much higher than the gold variant. ** Clear - No coating and mainly used in production processes. * Removable ceramic core elements use a coiled resistance heating alloy wire threaded through one or more cylindrical ceramic segments to make a required length (related to output), with or without a centre rod. Inserted into a metal sheath or tube sealed at one end, this type of element allows replacement or repair without breaking into the process involved, usually fluid heating under pressure. Combination heating element systems * Heating elements for high-temperature furnaces are often made of exotic materials, including platinum, tungsten disilicide/molybdenum disilicide, molybdenum (vacuum furnaces) and silicon carbide. Silicon carbide igniters are common in gas ovens. Laser heaters are also being used for achieving high temperatures. See also * Heated hose * Heating mantle * Positive temperature coefficient * Thermoelectric effect References Heating "
"Sūrat al-Maʻārij (, “The Ascending Stairways”) is the seventieth chapter (sūrah) of the Qur'an with 44 verses (āyāt). The Surah takes its name from the word dhil Ma'arij in 3rd ayah. The word appears twice in the Quran. Abdullah Yusuf Ali an Indian Islamic scholar introduces the surah as “This is another Islamic eschatology Surah closely connected in subject matter with the last one. Patience and the mystery of Time will show the ways that climb the Heaven. Sin and Goodness must each eventually come to its own.” Probable date of revelation Regarding the period of revelation of this surah, first one notes that this surah is Meccan.List of suras in the QuranQran.org: Quran Verses in Chronological Order This defines the period of revelation of this surah before 622 AD, the year of Hijra (Islam). In his translation of the Qur'an, one of the most widely known and used in the English-speaking world, Abdullah Yusuf Ali says “Chronologically it belongs to the late early middle Makkan period, possibly soon after Surah 69.” Sayyid Abul Ala Maududi in his Tafsir work Tafhim al-Qur'an writes: “The subject matter bears evidence that this Surah too was sent down in conditions closely resembling those under which Surah Al Haaqqah was sent down”. And records a tradition by Musnad Ahmad ibn Hanbal when Umar ibn Khattab told that he heard Muhammad reciting sura Al- Haaqqa Masjid al-Haram. Umar ibn Khattab accepted Islam in 616 ADUmar ibn Khattab#Converting to Islam so the surah Al-Ma'arij thus appears to reveal before 616 AD. Israr Ahmed, a Pakistani Islamic theologian, philosopher, and one of the noted Islamic scholar also holds the opinion that this surah was revealed in the 5th or 6th year of revelation and cites Fakhr al-Din al- RaziFakhr al-Din al-Razi#List of works and Abdul-Qadir Gilani in reference.Theodor Nöldeke places this chapter immediately after chapters lvi. and liii., probably because of the allusion of the first verse of this chapter to the beginning of chapter lvi. Muir places it in about the same period of time, which would fix the date at about the fifth year of the call of Muhammad to preach.Timeline of 7th-century Muslim historyCHAPTER LXX.: ENTITLED SURAT AL MAÁRIJ (THE STEPS). Revealed at Makkah. - Mohammed, The Quran, vol. 4 [1896]. Edition used: A Comprehensive Commentary on the Quran: Comprising Sale’s Translation and preliminary Discourse, with Additional Notes and Emendations (London: Kegan Paul, Trench, Trubner, and Co., 1896). 4 vols. Author: Mohammed; translator: George Sale; editor: Rev. Elwood Morris Wherry. Part of: The Quran, 4 vols. Asbab al-nuzul Asbāb al-nuzūl, an Arabic term meaning "occasions/circumstances of revelation", is a secondary genre of Qur'anic exegesis (tafsir) directed at establishing the context in which specific verses of the Qur'an were revealed. Though of some use in reconstructing the Qur'an's historicity, asbāb is by nature an exegetical rather than a historiographical genre, and as such usually associates the verses it explicates with general situations rather than specific events. Nasa'i and other traditionists have related a tradition from Ibn 'Abbas, and Hakim hold it as authentic, that Nadr bin al-Harith Kaladah had said "O God, if it is really the Truth sent dawn by You, then rain down stones on us from the heavens, or send down any other painful torment on us." (AI-Anfal: 32).Asbab al-Nuzul By: Ali ibn Ahmad al-Wahidi TRANSLATED BY Mokrane Guezzou Edited and with a brief Introduction by Yousef Meri The person here meant is generally supposed to have been al Nudár Ibn al Hárith, who said, ‘O God, if what Muhammad preaches be the truth from thee, rain down upon us a shower of stones, or send some dreadful judgment to punish us.’ Others, however, think it was Abú Jahl, who challenged Muhammad to cause a fragment of heaven to fall on them."—Sale,Sale, G., A Comprehensive Commentary on the Quran, (1896) Baidawi.The Secrets of Revelation and The Secrets of Interpretation (Asrar ut- tanzil wa Asrar ut-ta'wil) Abdul-Qadir Gilani an influential Islamic Sufi religious figure, teacher, preacher and writer however holds the opinion that the demand for torment referred in the 1st ayah of this surah was made by Prophet Muhammad himself for the disbelievers due to the increasing Persecution of Muslims by the Meccans. And for example Dr.Israr Ahmed cites the demand of torment by prophet Nūḥ against his people in the next surah which is also the pair of surah Al-Ma'arij. For references Dr. Israr Ahmed cites the works of Fakhr al-Din al-Razi and Abdul-Qadir Gilani. Theme and subject matter Sayyid Qutb an Egyptian author, educator and Islamic theorist in his magnum opus, Fi Zilal al-Quran (In the shade of the Qur'an), a 30-volume commentary on the Qur'an summarizes the overview of surah Al-Ma'arij in these words." We may say that this surah represents a round in the long, hard battle the Qur'an fights within the human soul, going deep inside it to eradicate all lingering traces of jahiliyyah. This battle is greater and longer lasting than the wars the Muslims later had to fight against their many enemies.".Fi Dhilal al-Quran. Beirut: Dar al-Shurruq (1981) He further elaborates: > The major issue the surah focuses on is that of the hereafter and peoples > requital for what they do during their lives on earth, particularly the > punishment suffered by the unbelievers. In order to establish the truth of > the hereafter, the surah speaks of how the human soul reacts to situations > of hardship and comfort. Such reactions differ greatly between a believer > and one who is devoid of faith. The surah also provides an outline of the > believers' main features, their feelings and behaviour, and it states how > they deserve to be honoured. It also shows that the unbelievers are held in > disregard by God, and gives a picture of the humiliation prepared for them. > It is a humiliation the arrogant thoroughly deserve. Furthermore, the surah > establishes the fact that values, standards and scales applied by God are > different from those which human beings uphold. " —Sayid Qutb, Fi Zilal al- > Qur'an Javed Ahmad Ghamidi (b. 1951), a well-known Pakistani Muslim theologian, Quran scholar and exegete, and educationist, classifies surah Al-Ma'arij as a pair with the last one with regard to the subject discussed in them. He also suggests that the primary audience of surah Al-Ma'arij is leadership of the Quraysh. Regarding the central theme of the surah Ghamidi summarizes: > The central theme of Surah Ma‘arij is to warn those among the Quraysh of > their fate who are making fun of the consequences of denying the Inzar of > the Qur’an about the Day of Judgement and are asking to hasten their advent, > and to urge the Prophet (sws) to persevere in the cause of truth and to tell > the unbelievers that Paradise is the reward of all good deeds; a person > whose evil deeds outnumber his good ones even if he is from the high ups of > the society shall never enter this everlasting kingdom.—Ghamidi The major scholars of Islam agree(Ijma) about the theme and subject matter of this surah.http://www.alim.org/library/quran/surah/introduction/70/MAL In fact the study of surah AL-Marij stated by various scholars overlaps each other. Just like the above-mentioned exegetes, Muhammad Farooq-i-Azam Malik states his understanding of the Major Issues, Divine Laws and Guidance in surah Al- Ma'arij as: > "The whole Surah is meant to answer this question saying: "Resurrection, > which they desire to be hastened out of jest and fun, is terrible, and when > it comes, it will cause great distress to the culprits. At that time they > will even be prepared to give away their wives and children and their > nearest kinfolks in ransom to escape the punishment, but they will not be > able to escape it. On that Day, the destinies of mankind will be decided > strictly on the basis of their belief and their conduct. Those who turn away > from the Truth in this world, amass wealth and withhold it from the needy, > will be doomed to hell; and those who fear the punishment of Allah, believe > in the Hereafter, establish Salah (keep up the prayers), discharge the > rights of the needy out of their wealth, strictly avoid immoral and wicked > deeds, practise honesty in all their dealings, fulfill their pledges and > trust and bear true witness, will have a place of honor in paradise" - > Muhammad Farooq-i-Azam MalikMuhammad Farooq-i-Azam Malik (translator), Al- > Qur'an, the Guidance for Mankind - English with Arabic Text (Hardcover) Contents The Quranic text has been divided into separate rukus in terms of thematically related Ayah. This surah contains 2 rukus. The contents of the 1st Ruku states that the day of judgement will be equal to fifty thousand years and disbelievers will wish to save themselves from the punishment at the expense of their children, wives, brothers and relatives, but it will not happen. 2nd Ruku starts from ayah 36 and continues uptill the end of the surah and it states that the Paradise is not for the disbelievers and Disbelievers will have downcast eyes and countenances distorted with shame.http://www.alim.org/library/quran/ayah/theme/70 Another noticeable fact about this surah needs to be addressed that passage 70:29 to 70:32 is completely identical to the passage Al-Mu'minoon 23:5 to 23:8. About this presence of repetition"The final process of collection and codification of the Quran text was guided by one principle: God's words must not in any way be distorted or sullied by human intervention. For this reason, no serious attempt, apparently, was made to edit the numerous revelations, organize them into thematic units, or present them in chronological order.... This has given rise in the past to a great deal of criticism by European and American scholars of Islam, who find the Quran disorganized, repetitive and very difficult to read." Approaches to the Asian Classics, Irene Blomm, William Theodore De Bary, Columbia University Press, 1990, p. 65 Michael Sells, citing the work of the critic Norman O. Brown, acknowledges Brown's observation that the seeming disorganization of Quranic literary expression – its scattered or fragmented mode of composition in Sells's phrase – is in fact a literary device capable of delivering profound effects as if the intensity of the prophetic message were shattering the vehicle of human language in which it was being communicated.Michael Sells, Approaching the Qur'an (White Cloud Press, 1999)Norman O. Brown, "The Apocalypse of Islam." Social Text 3:8 (1983–1984) Sells also addresses the much-discussed repetitiveness of the Quran, seeing this, too, as a literary device. A text is self-referential when it speaks about itself and makes reference to itself. According to Stefan Wild the Quran demonstrates this meta-textuality by explaining, classifying, interpreting and justifying the words to be transmitted. Self-referentiality is evident in those passages when the Quran refers to itself as revelation (tanzil), remembrance (dhikr), news (naba'), criterion (furqan) in a self- designating manner (explicitly asserting its Divinity, "And this is a blessed Remembrance that We have sent down; so are you now denying it?" (21:50), or in the frequent appearance of the 'Say' tags, when Muhammad is commanded to speak (e.g. "Say: 'God's guidance is the true guidance' ", "Say: 'Would you then dispute with us concerning God?' "). According to Wild the Quran is highly self-referential. The feature is more evident in early Meccan chapters.Quran#Literary style Abul A'la Maududi (September 25, 1903 – September 22, 1979) was a journalist, theologian, Muslim revivalist leader and political philosopher, and a 20th-century Islamist thinker in India, and later Pakistan.Zebiri, Kate. Review of Maududi and the making of Islamic fundamentalism. Bulletin of the School of Oriental and African Studies, University of London, Vol. 61, No. 1.(1998), pp. 167–168. He was also a political figure in Pakistan and was the first recipient of King Faisal International Award for his services in 1979.Abul A'la MaududiAbul A'la Maududi#Legacy He summarizes the contents of the surah in these words: > It admonishes and gives warning to the disbelievers who made fun of the news > about Resurrection and the Hereafter, and Hell and Heaven, and challenged > the Holy Prophet (upon whom be peace) to cause Resurrection with which he > threatened them to take place if what he said was true and they had become > worthy of the punishment in Hell by denying it. The whole Surah is meant to > answer this denial. The Surah opens with words to the effect:"A demander has > demanded a torment, the torment which must befall the deniers; and when it > takes place, there will be none to prevent it, but it will take place at its > own appointed time. Allah has His own way of doing things, but He is not > unjust. Therefore, have patience, O Prophet, at what they say. They think it > is far off, but We see it as near at hand." Then it is said:"Resurrection, > which they desire to be hastened out of jest and fun, is terrible, and when > it comes, it will cause great distress to the culprits. At that time they > will even be prepared to give away their wives and children and their > nearest kinsfolk in ransom to escape the punishment, but they will not be > able to escape it. Then the people have been warned to the effect; "On that > Day the destinies of men will be decided strictly on the basis of their > belief and their conduct. Those who turn away from the Truth in the world > and amass wealth and withhold it from the needy, will be doomed to Hell; and > those who fear the punishment of God here, believe in the Hereafter, keep up > the Prayer, discharge the rights of the needy out of their wealth, strictly > avoid immoral and wicked deeds, practice honesty in all their dealings, > fulfill their pledges and trust and bear true witness, will have a place of > honor in Paradise" In conclusion, the disbelievers of Makkah who rushed in > upon the Holy Prophet (upon whom be peace) from every side as soon as they > saw him, in order to make fun of him, have been warned to the effect: "If > you do not believe, Allah will replace you by other people who will be > better than you", and the Holy Prophet (upon whom be peace) has been > consoled, so as to say: "Do not take to heart their mockery and jesting; > leave them to indulge in their idle talk and foolish conduct if they are > bent upon experiencing the disgrace and humiliation of the Resurrection; > they will themselves see their evil end."'—Abul A'la Maududi, Tafhim-ul- > QuranTafhim al-Qur'an. Lahore: Islamic Publications, Ltd. (1981) See also * Ma malakat aymanukum * Al-Mu'minoon ReferencesExternal links Maarij "
"Sūrat Nūḥ (, “Noah”) is the seventy-first surah of the Quran with 28 ayat. It is about the Islamic prophet Nūḥ and his complaint about his people rejecting all warning Allah gave them through Nuh. Nuh's themes include: belief in Allah, signs of Allah (the Earth, Sun, Moon), and punishment of denying Allah's message. Summary In Nuh, the seventy-first surah, the Quran refers to Nuh’s prophethood in snippets. Nuh is a messenger of Allah. When Nuh realizes the messages are not accepted by the community, he supplicated to Allah, who planned to flood the community of Nuh at a specified time. Allah commanded Nuh to warn the people of the flood. Allah brings forth the water from the skies to prove Nuh’s message to be accurate. In the Quran, the flood is a symbolization of the mercy of Allah to the believers. Allah gives the world a new beginning. The disbelievers disbelieved Allah's message and messenger Nuh so they were drowned. Because his people are unable to grasp the idea of the existence of one God, the lives of Muhammad and Nuh are parallel to each other for the time of the revelation of this surah. The surah was used to increase the faith of the believers; it shows that Nuh before Muhammad had difficulties in dealing with the disbelievers of his time. Exegesis=Q71:1-4 Noah receives message from God Verses 1–4 discuss the message Nuh received from God (Allah) to share with his community, to serve God. Q71:5-20 the Earth, the sun, the moon are signs of God's existence. In Verses 5–20, Nuh informs Allah that his people are not accepting his message. Nuh tries to make clear to the people that all of the Earth, the Sun, the Moon are signs of God's existence. Q71:21-25 rid the world of the evildoers In Verses 21–24, Nuh asks Allah to rid the world of the evildoers because they refused to abandon their idols and encourage others to do the same. Q71:26-28 disbelievers all drowned In Verses 26–28, the disbelievers were all drowned and sent to hell (as a result of the flood). Nuh asks Allah to forgive the believers and to destroy the disbelievers because their faith will lead many astray. Surah chronology The surah is entirely Meccan meaning it was revealed while Muhammad was trying to create a Muslim community in Mecca. According to the Tanzil version, it was the seventy-first surah revealed. It was revealed after the sixteenth surah, An-Nahl ("The Bee") and before the fourteenth Ibrahim ("Abraham"). According to Theodor Nöldeke, Nūḥ was the fifty-third surah to be revealed. It was revealed after the thirty- seventh surah Saaffaat ("Those Who Set The Ranks"), and before the seventy- sixth surah, Insaan or Dahr ("Man" or "Time"). ReferencesExternal links Noah Nuh "