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1
Gordon, Carolyn, David L. Webb, and Scott Wolpert. "One Cannot Hear the Shape of a Drum." Bulletin of the American Mathematical Society 27, no. 1 (July 1, 1992): 134–39. http://dx.doi.org/10.1090/s0273-0979-1992-00289-6.
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CIPRA, B. "You Can't Hear the Shape of a Drum." Science 255, no. 5052 (March 27, 1992): 1642–43. http://dx.doi.org/10.1126/science.255.5052.1642.
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LAPIDUS, MICHEL L. "FRACTALS AND VIBRATIONS: CAN YOU HEAR THE SHAPE OF A FRACTAL DRUM?" Fractals 03, no. 04 (December 1995): 725–36. http://dx.doi.org/10.1142/s0218348x95000643.
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We study various aspects of the question “Can one hear the shape of a fractal drum?”, both for “drums with fractal boundary” (or “surface fractals”) and for “drums with fractal membrane” (or “mass fractals”).
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Zuluaga, S., and F. Fonseca. "Can’t one really hear the shape of a drum?" Acoustical Physics 57, no. 4 (July 2011): 465–72. http://dx.doi.org/10.1134/s106377101104021x.
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Amar, Martien Ben, and Patrício Da Silva. "Can one hear the shape of a smectic drum?" Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences 454, no. 1978 (October 8, 1998): 2757–65. http://dx.doi.org/10.1098/rspa.1998.0279.
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Protter, M. H. "Can One Hear the Shape of a Drum? Revisited." SIAM Review 29, no. 2 (June 1987): 185–97. http://dx.doi.org/10.1137/1029041.
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Okada, Y., A. Shudo, S. Tasaki, and T. Harayama. "‘Can one hear the shape of a drum?’: revisited." Journal of Physics A: Mathematical and General 38, no. 9 (February 17, 2005): L163—L170. http://dx.doi.org/10.1088/0305-4470/38/9/l02.
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Bari, Naveed S., and Eugenie Hunsicker. "Isospectrality for Orbifold Lens Spaces." Canadian Journal of Mathematics 72, no. 2 (August 27, 2019): 281–325. http://dx.doi.org/10.4153/s0008414x19000178.
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AbstractWe answer Mark Kac’s famous question, “Can one hear the shape of a drum?” in the positive for orbifolds that are 3-dimensional and 4-dimensional lens spaces; we thus complete the answer to this question for orbifold lens spaces in all dimensions. We also show that the coefficients of the asymptotic expansion of the trace of the heat kernel are not sufficient to determine the above results.
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BEALS, RICHARD, and PETER C. GREINER. "STRINGS, WAVES, DRUMS: SPECTRA AND INVERSE PROBLEMS." Analysis and Applications 07, no. 02 (April 2009): 131–83. http://dx.doi.org/10.1142/s0219530509001335.
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This survey treats a number of interconnected topics related in one way or another to the famous paper of Mark Kac, "Can one hear the shape of a drum?": wave motion, classical and quantum inverse problems, integrable systems, and the relations between spectra and geometry. We sketch the history and some of the principal developments from the vibrating string to quantum inverse problems, the KdV equation and integrable systems, spectral geometry and the index problem.
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Johnson, Henry. "Chinese toms in the making of the drum kit: Localization and exoticism." Journal of Popular Music Education 5, no. 2 (July 1, 2021): 227–42. http://dx.doi.org/10.1386/jpme_00059_1.
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The late nineteenth century and early decades of the twentieth century saw the drum kit emerge as an assemblage of musical instruments that was central to much new music of the time and especially to the rise of jazz. This article is a study of Chinese drums in the making of the drum kit. The notions of localization and exoticism are applied as conceptual tools for interpreting the place of Chinese drums in the early drum kit. Why were distinctly Chinese drums used in the early drum kit? How did the Chinese drums shape the future of the drum kit? The drum kit has been at the heart of most popular music throughout the twentieth century to the present day, and, as such, this article will be beneficial to educators, practitioners and scholars of popular music education.
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Thas, Koen. "Isospectral drums and simple groups." International Journal of Geometric Methods in Modern Physics 15, no. 04 (March 13, 2018): 1850060. http://dx.doi.org/10.1142/s0219887818500603.
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Nearly every known pair of isospectral but nonisometric manifolds — with as most famous members isospectral bounded [Formula: see text]-planar domains which makes one “not hear the shape of a drum” [M. Kac, Can one hear the shape of a drum? Amer. Math. Monthly 73(4 part 2) (1966) 1–23] — arise from the (group theoretical) Gassmann–Sunada method. Moreover, all the known [Formula: see text]-planar examples (so counter examples to Kac’s question) are constructed through a famous specialization of this method, called transplantation. We first describe a number of very general classes of length equivalent manifolds, with as particular cases isospectral manifolds, in each of the constructions starting from a given example that arises itself from the Gassmann–Sunada method. The constructions include the examples arising from the transplantation technique (and thus in particular the known planar examples). To that end, we introduce four properties — called FF, MAX, PAIR and INV — inspired by natural physical properties (which rule out trivial constructions), that are satisfied for each of the known planar examples. Vice versa, we show that length equivalent manifolds with FF, MAX, PAIR and INV which arise from the Gassmann–Sunada method, must fall under one of our prior constructions, thus describing a precise classification of these objects. Due to the nature of our constructions and properties, a deep connection with finite simple groups occurs which seems, perhaps, rather surprising in the context of this paper. On the other hand, our properties define in some sense physically irreducible pairs of length equivalent manifolds — “atoms” of general pairs of length equivalent manifolds, in that such a general pair of manifolds is patched up out of irreducible pairs — and that is precisely what simple groups are for general groups.
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Dehideniya, Isuru. "The Comparative Study of Form and the Structure of Sri Lankan Gaṭaberā and Pahatharaṭa Berā with the Indian Mridanga Drum." International Journal of Cultural and Art Studies 5, no. 2 (October 31, 2021): 70–81. http://dx.doi.org/10.32734/ijcas.v5i2.6822.
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The Gaṭaberā and Pahataraṭa berā are the main drums in two regions in Sri Lanka; also the Mridanga is one of all South Indian main drums. This research is a comparative analysis of the similarities and differences of form and structure between those Indians and Sri Lankans drums. That is conducted in the qualitative method. Several similarities and differences are discovered from the form and structure between those drums under the organization, order of the elements, construct process, and shape. The final conclusions are, 1) the form of all drum heads of Gatabera, Pahatharata bera, and Mridanga is similar, and also that form represents an Indian subcontinent drum head variety, but their structure is different according to the culture of both countries. 2) The form and structure of Gatabera and Mridanga drum bodies are slightly similar.
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Bader, Rolf. "Finite-difference model of mode shape changes of the Myanmar pat wain drum circle with tuning paste on drum head." Journal of the Acoustical Society of America 140, no. 4 (October 2016): 3142. http://dx.doi.org/10.1121/1.4969851.
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Fidrovska, Nаtalya, Viktoria Nesterenko, and Ruslan Karavan. "Methodology for calculating rope drums for stability." Bulletin of Kharkov National Automobile and Highway University, no. 95 (December 16, 2021): 83. http://dx.doi.org/10.30977/bul.2219-5548.2021.95.0.83.
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. The problems of the stability of rope drums are quite urgent. The rope drum is in most cases a thin-walled shell, which, under the influence of external pressure from the rope, can lead to loss of stability. The stability issues of the drum shell, which is loaded with rope turns, are very important, because the safety and reliability of the rope hoist is directly related to them The studies carried out made it possible to obtain a new method for calculating the stability of cylindrical shells, which takes into account not only the length of the shell, but also the rigidity of the connection with the head. In addition, a calculation formula was obtained to determine the critical pressure of the oval shell, which gives a fairly good agreement with the experiments of American scientists. The work also considered the effect of the difference in wall thickness on the critical load of the drum. The studies carried out made it possible to conclude that the parameters of the rope drums make it possible to completely eliminate the need to install rings and stiffeners. Also as a result of research it was found that the shell of the crane drum under the influence of a radial load cannot lose stability. Studies have shown that in all cases the stability margin of the rope drum shell is greater than the strength margin. In this case, the load created by the rope wound on the drum is considered, with the ratios of the radius of the drum and the rope typical for crane construction. In addition, a coefficient was established that takes into account the elasticity of the shell-head joint. The studies carried out have shown that such initial deviations of the drum shell shape as ovality do not give a significant increase in the critical load. The results obtained are quite important, since they allow reducing the metal consumption of the rope drum shell and at the same time ensuring its reliable operation. A decrease in metal consumption is achieved by reducing the thickness of the shell and the absence of the need to install rings and stiffeners. This will lead to a decrease in metal consumption and energy consumption of the crane itself, and also simplifies the technology of manufacturing a rope drum.
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FARBER, MICHAEL, JEAN-CLAUDE HAUSMANN, and DIRK SCHÜTZ. "ON THE CONJECTURE OF KEVIN WALKER." Journal of Topology and Analysis 01, no. 01 (March 2009): 65–86. http://dx.doi.org/10.1142/s1793525309000023.
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In 1985 Kevin Walker in his study of topology of polygon spaces [15] raised an interesting conjecture in the spirit of the well-known question "Can you hear the shape of a drum?" of Marc Kac. Roughly, Walker's conjecture asks if one can recover relative lengths of the bars of a linkage from intrinsic algebraic properties of the cohomology algebra of its configuration space. In this paper we prove that the conjecture is true for polygon spaces in R3. We also prove that for planar polygon spaces the conjecture holds in several modified forms: (a) if one takes into account the action of a natural involution on cohomology, (b) if the cohomology algebra of the involution's orbit space is known, or (c) if the length vector is normal. Some of our results allow the length vector to be non-generic, the corresponding polygon spaces have singularities. Our main tool is the study of the natural involution and its action on cohomology. A crucial role in our proof plays the solution of the isomorphism problem for monoidal rings due to Gubeladze.
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Fámúlẹ̀, Oláwọlé. "Èdè Àyàn: The Language of Àyàn in Yorùbá Art and Ritual of Egúngún." Yoruba Studies Review 2, no. 2 (December 21, 2021): 1–50. http://dx.doi.org/10.32473/ysr.v2i2.129886.
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Kò séní m’èdè Àyàn
Bí ení mú kò ̣ ̣ǹgó ̣ è ̣ lówọ́
No one understands the language of Àyàn Better than the drummer who holds the gong in his hand Yorùbá maxim
From the Yorùbá oral historical, mythological, and ontological, abstract lines of reasoning, Àyàn is believed to be the first Yorùbá drum maker and drummer, who, after his death, was deified as the god of Drumming (Òrìsà ̣ Àyàn, or simply Àyàn). Hence, when an experienced Yorùbá drummer plays his drum masterfully, the elders with the drum speech discernable ears (òmò ̣ ràn) that hear the drumming, even from afar commend, “may Àyàn, ̣ the god of drumming prosper/ protect you!” (Àyàn ó gbè ó!). As among other Yorùbá deities (òrìsạ̀) that live in the spiritual realm in certain but uncommon natural environments (forests, trees, rivers, streams, and mountains, among others), Òrìsà Àyàn is thought to reside in wood (Vil ̣ - lepastour 2015, 3). For this reason, Òrìsà Àyàn is emblematized by the wood ̣ with which the body of the drum (ìlù) is carved. Similarly, this deity is eulogized as “the spirit who speaks out from inside his wooded abode” (Òrìsà ̣ gbé’nú igi fohùn), in reference to the log of wood with which the drums (ìlù) are carved. It is said that Òrìsà Àyàn particularly prefers that ìlù be carved ̣ with Cordia millenii (igi òmò ̣ ), a belief that gave birth to the Yorùbá saying, ̣ “out of the entire wood species of the forests is the preferred Cordia millenii, with which gbèdụ drum is carved” (Igi gbogbo ní ńbe ̣ ní’gbó, k’átó fi’gi òmò ̣ ̣ gbé ̣ gbèdụ). Because of his position as the patron deity of drumming, which 2 Oláwọlé Fámúlẹ̀ by extension is used to accompanying sacred rites in honor of virtually all the Yorùbá òrìsạ̀, Òrìsà Àyàn is thought to be their mouthpiece, as they all speak ̣ through the drums that he emblematizes. Another emblem of Òrìsà Àyàn that ̣ is even worshipped is a shallow hemispherical drum with a single fixed head, which is worn on the chest with a strap around the neck and beaten with leather straps held in each hand (gúdúgúdú ) (Bascom 1952, 4). The gúdúgúdú symbol of Òrìsà Àyàn also goes by the praise name (oríkì) “gúdúgúdú with its distinctive uneven and undulated back shape” (Gúdúgúdú, ab’è yìn jákan- ̣ jàkan). The component parts that formed this uneven and surged-back shape [of gúdúgúdú] include kúseré and apìràn. Kúseré is a circular metal object affixed onto the drum’s wooded base, and apìràn is an array of wooden pegs that hold the kúseré securely onto the base of the instrument. At the exoteric and practical level, Àyàn also refers to any Yorùbá traditional and professional drummer, who plays the drum (ìlù), often with the use of a gong (kòṇ̀ gó).̣ The Yorùbá professional drummers share the name àyàn with Òrìsà Àyàn since they are the human agents who play the drums (ìlù), ̣ emblem of Òrìsà Àyàn, and through which the deity speaks. The ̣ Yorùbá incantation “the day that the drummer drums with his gong/drumstick is the very moment that the Àyàn god of drumming speaks out that which is in his mouth” (Òòjó ̣ tí kòṇ̀ gó ̣ Àyàn bá f’ojú ba ìlù ni Òrìsà Àyàn ̣ ńpo ̣ t’enu rè ̣ ̣ sí’lè) ̣ best illustrates the interconnection of the drummers (àyàn) with god of drumming, Òrìsà Àyàn. As succinctly corroborated by Amanda Villepastour, “the ̣ drummer in action becomes Àyàn.” Another Yorùbá term for a drummer (àyàn) is onílù. 1 With their drumming (or drum music) that mimic the human speech, the Àyàn or Onílù verbalize words/speeches (òrọ̀ ) that is or are intelligible to the ears of their ̣ patrons, often the dance performers (oníjó). For that reason, ìlù, to the Yorùbá, is an instrument that acts as a speech surrogate (i.e., substitute). That the Yorùbá refer to ìlù as “the talking drum” underscores this assertion. In fact, they strongly believed that if handled by a skillful drummer (àyàn/onílù), ìlù, just like humans, can speak words or communicate effectively to those who understand the language of the drum. The Yorùbá phrase “a lifeless goat that speaks just like a human” (òkú-ewúré tíí fo ̣ ’hùn bí ènìyàn ̣ ), a euphemism for the goatskin fixed single- or double-headed hourglass drums that mimic human speech when drummed, is a testimony to ìlù as a true “talking drum.” Another Yorùbá saying that illustrates that ìlù is an instrument of language substitution is “that the gángan drum could speak in a human nasal tone of 1 Onílù is formed from two Yorùbá words oní and ìlù (literally, “owner of the drum” or “one who plays the drum”), a euphemism for the drummer. Thus, anybody that plays drum is an onílù. But those Yorùbá traditional professional onílù, like the dùndún and bàtá drummers, are specifically referred to as àyàn. Èdè Àyàn: The Language of Àyàn in Yorùbá Art and Ritual of Egúngún 3 voice is not without the help of the drummer’s own tip of the fingernails” (àti rán’mú gángan kò s’ẹ̀ yìn èékáná ̣ ). In Yorùbá traditional festivals, ritual performances, and religious practices in general, the role of àyàn whose drumming or drum music imitate and code the natural language (Yorùbá), cannot be overemphasized. The Yorùbá aphorism “without drum music, there is no way to celebrate” (láì sí’lù, taní jé ̣ s’eré òkúrùgbe!̣) is a testimony to the indispensable role of ìlù in the context of traditional Yorùbá visual and performance arts. A clear example is the Yorùbá art and ritual of Egúngún, the theme of this study. Paradoxically, many Yorùbá art scholars often make very little or no effort to explore the relevance of ìlù in their studies on Yorùbá visual culture, such as Egúngún. This has continued to make it become virtually impossible for a deeper understanding of Yorùbá art in particular and African art as a whole. Ironically, the same scholars prefer to invest their energy, searching outside of the art’s cultural origin to fulfil their primary goal of “appreciating” the African art, rather than searching within African culture, language and values, the very driving forces that gave rise to this art, and thus a catalyst to understanding it.2 It is on that note that I believe the question that scholars of African art should begin to ask themselves is: when will African art scholarship––unlike Western art studies that often demand intellectual rigor and professional thoroughness––rise above its present art “appreciating” status vis-à-vis African art? In my opinion, as this present study is aimed at confirming, the understanding of African art critically requires that scholars be fluent or at least confident in the reading, writing, and speaking of the language of the people whose art they study. Also heightening the problem of the lack of “understanding” of Yorùbá art is the very unique nature of it (as with other African art), in which an isolated work of art in context is a rarity. Thus, the present study examines the very indispensable roles of Àyàn drummers in the performance context of the annual Egúngún festival (odún Egúngún) in a Yorùbá community in Òkèigbó in Nigeria’s Ondo State. As a native speaker with access to Yorùbá philosophy, values and history, and who is fully aware of the fundamental importance of language in African art studies, I aim in this study to examine the mutual relationship existing between the Àyàn and Egúngún from the vantage point of the Yorùbá language, the medium through which the said Yorùbá philosophy, values and history are stored and expressed. It delves into the very root of Egúngún within the Yorùbá cultural context, where traditions and history are preserved and recorded not in the western-type of writing, but rather in the Yorùbá language, ritual performance and ceremonies. It is hoped that this study will facilitate a deeper understanding of Egúngún along with the 2 Personal communication with Professor Rowland Abíodún on April 2, 2017. 4 Oláwọlé Fámúlẹ̀ àyàn within the art and ritual performance context of the Odún Egúngún. The study illustrates the interconnection of the àyàn and Egúngún by first providing an overview of Yorùbá drums and their ritual contexts. This is followed by a close study of the Yorùbá ontological concept of Egúngún, one of the most valued patrons of Àyàn (the drummers), as an important form of Yorùbá religious beliefs and practices. Using the Egbé ̣ ̣ Òjẹ̀ ̣ (Cult of Egúngún) of the ancient Yorùbá town of Òkèigbó as a case study, the study concludes with an in-depth analysis of the role of Àyàn (Drummers) in Yorùbá art and ritual of Egúngún.
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Almeida, A., M. Adjuntsov, W. Bushura, E. Delgado, M. Drasher, M. Fernando-Pancho, M. Gasane, et al. "Hear us! Accounts of people treated with injectables for drug-resistant TB." Public Health Action 11, no. 3 (September 21, 2021): 146–54. http://dx.doi.org/10.5588/pha.21.0031.
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BACKGROUND: WHO drug-resistant TB (DR-TB) treatment recommendations now emphasize all-oral regimens, recommending against certain injectable agents and deprioritizing others due to inferior safety and efficacy. Despite increasing focus on patient-centered care, we are not aware of systematic attempts to qualitatively document patients’ perspectives on injectable agents. This may inform implementation of WHO guidelines, emphasizing the importance of consultation with affected communities.METHODS: Testimonies were provided by TB survivors who experienced hearing loss from treatment with injectable agents. Testimonies were submitted in writing in response to minimal, standardized, open-ended prompts. Participants provided a signed consent form (with options to participate anonymously or as a named co-author), and later gave input into the overall shape and recommendations of the article.RESULTS: Fourteen TB survivors in 12 countries contributed testimonies. The following common themes emerged: lack of access to appropriate testing, information, treatment, or a collaborative treatment environment; the power of supportive care and social environments; stigma and isolation from TB treatment itself and resultant disability; and inaccessibility of cochlear implants.CONCLUSIONS: Survivor testimonies indicate strong preferences for avoidance of injectable agents, supporting rapid implementation of revised WHO guidelines, as well as for quality and supportive care for both TB and disabilities.
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Nussupbekov, Bekbolat, Yerlan Oshanov, Michael Ovcharov, Elmira Mussenova, Didar Ospanova, and Madina Bolatbekova. "Development and creation of a hydrodynamic liquid heating unit." Eastern-European Journal of Enterprise Technologies 5, no. 8(119) (October 30, 2022): 62–69. http://dx.doi.org/10.15587/1729-4061.2022.264227.
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The work is devoted to the study of the parameters of an installation for heating a coolant using liquid forcing through throttle openings. A scheme of a full-size experimental stand has been developed and the principles of operation are described in detail. For visual observation of the state of the liquid at different angular speeds of rotation of the rotor, a transparent drum model is made. The influence of the shape of the rotor skirt and the depth of its immersion in the liquid on the filling capacity of the rotor cavity at an angular velocity from 42 to 314 rad/s has been determined. The optimal parameters of the depth of immersion of the drum skirt with a diameter of 0.5 m in the liquid, at low rotor speeds of 16, 24, 32 rad/s, were obtained. The angle of inclination is calculated and it is experimentally proved that for a conical shape it is 5 degrees. It was found that at angular velocities of the rotor more than 100 rad/s, the shape and depth of immersion of the skirt in the liquid do not affect the filling of the rotor, since the feed is higher than its flow through the throttle openings. It is shown that the use of rotational forces to heat the liquid allows using an electric motor with less power, since it is spent only on unwinding the rotor with the liquid. The calculated dependence of the liquid pressure on the side walls of the rotor, the liquid heating temperature on the angular velocity of rotation of the rotor and on two values of the area of the throttle openings, at 31.4·10-6 m2 and 64.34·10-6 m2, is obtained. When the total area of the throttle openings is doubled, the temperature of the liquid heating at the same angular velocities increases from 35.6 °C to 82.5 °C. The above installation parameters allow you to get hot water when using small shell-and-tube heat exchangers
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Maláková, Silvia, Samuel Sivák, and Jozef Krajňák. "GEARBOX LUBRICATION SYSTEM OPTIMIZATION." Acta Mechatronica 6, no. 2 (June 30, 2021): 21–24. http://dx.doi.org/10.22306/am.v6i2.75.
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The aim of gearbox lubrication is to reduce wear on the sides of the teeth, increase of the efficiency by reducing friction as well as dissipating the heat generated by friction. Lubrication of gearboxes is a discontinuous process, that means, during the meshing every meshed pair of teeth needs to have a new lubrication film created on the surfaces. The geometric shape of the sides of the teeth is conditioned by rolling and sliding movement, therefore gears often work under a mixed friction condition. This is confirmed by damage to gearboxes and by measured power losses. This contribution is devoted to the issue of innovation of the original lubrication of the first stage of the bevel helical gearbox used for the drive of the rope drum.
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Wang, Oliver. "Hear the Drum Machine Get Wicked." Journal of Popular Music Studies 26, no. 2-3 (June 2014): 220–25. http://dx.doi.org/10.1111/jpms.12074.
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Sun, Zelin, Yuting Li, Xin Qi, Shude Ji, Zhen Jia, Feng Li, and Yewei Zhang. "Material Flow and Mechanical Properties of a Non-Keyhole Friction Stir Welded Aluminum Alloy with Improved Sleeve Bottom Geometry." Metals 12, no. 9 (August 26, 2022): 1415. http://dx.doi.org/10.3390/met12091415.
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Non-keyhole friction stir welding (N-KFSW) is a technique that can fabricate a welding joint without a keyhole through a one-time welding process. The Al–Mg–Si alloy was chosen as a research object, and the N-KFSW technique was investigated by numerical and experimental methods. Firstly, the sleeve bottoms of the N-KFSW welding tool system were innovatively optimized in this study. The optimal sleeve bottom with an 80° angle between the spiral groove and the sleeve inner side wall allowed avoiding the incomplete root penetration defect at the bottom of the stir zone (SZ), which was verified by numerical results and the C-shaped line height. Then, using a 3 mm-thick aluminum alloy as the experimental material, the material flow and joint formation characteristics and mechanical properties at 110, 150 and 190 mm/min welding speeds were studied and compared. The results showed that the SZ presented a drum shape due to the action of the clamping ring and the threads on the side wall of the sleeve. The SZ width decreased from 7.17 to 6.91 mm due to the decreased heat input. From 70 to 210 mm/min welding speed, the maximum tensile strength of the joint was 250 MPa at 190 mm/min, and the joint with relatively higher strength fractured at the heat-affected zone.
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Husaini, Fahri, Syafriandi Syafriandi, and Mustaqimah Mustaqimah. "Uji Kinerja Mesin Penyangrai Biji Kopi Tipe Rotary Drum dengan Penambahan Isolator." Jurnal Ilmiah Mahasiswa Pertanian 7, no. 1 (March 11, 2022): 582–89. http://dx.doi.org/10.17969/jimfp.v7i1.19151.
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Abstrak. Seiring perkembangan teknologi, mesin penyangraian akan terus berkembang sehingga akan menghasilkan produk biji kopi yang berkualitas. Kopi bubuk adalah biji kopi yang telah disangrai, digiling atau ditumbuk hingga menyerupai serbuk halus. Proses penyangraian bertujuan pembentukan rasa dan aroma pada biji kopi. Mesin sanggrai biji kopi yang digunakan dalam penelitian ini berupa tipe rotary drum. Mesin penyangrai ini terdiri dari tabung luar dan tabung dalam. Tabung dalam berfungsi sebagai tempat biji kopi dan diputar oleh dynamo listrik. Tabung luar berfungsi mirip seperti oven sebagai pemanas ruang sangrai yang panasnya bersumber dari heater yang disalurkan ke elemen pemanas. Penambahan insulator jenis busa alumunium foil melapisi seluruh dinding luar mesin penyangrai perlu dilakukan untuk meminimalkan kehilangan energi panas pada mesin tersebut. Tujuan dari penelitian ini adalah menguji kinerja mesin penyangrai biji kopi rotary drum dengan penambahan isolator. Data yang perlu diukur dan dihitung dari mesin penyangrai ini adalah suhu ruang penyangrai, kebutuhan daya listrik dan kehilangan energi penyangraian. Pengukuran kadar air biji kopi sebelum dan setelah penyangraian juga perlu diketahui. Suhu ruang penyangrai mencapai kisaran 113oC sampai dengan 140oC. Daya yang dibutuhkan adalah 2.565 watt selama 50 menit penyangraian. Kehilangan energi penyangraian tergolong kecil sekitar 0.36 MJ. Dapat disimpulkan bahwa penambahan insolator dapat mengurangi kehilangan energi.Performance Test of Coffee Roaster Machine Rotary Drum Type by Adding an IsolatorAbstract. Along with technological developments, roasting machines will continue to develop so that they will produce quality coffee beans. Ground coffee is coffee beans that have been roasted, ground to a fine powder. The roasting process aims to shape the taste and aroma of the coffee beans. The coffee bean roaster used in this study is a rotary drum type. This roaster consists of an outer tube and an inner tube. The inner tube serves as a coffee bean holder and is rotated by an electric dynamo. The outer tube functions like an oven as a space heater whose heat is sourced from the heater which is channeled to the heating element. The addition of aluminum foil foam type insulator to coat the entire outer wall of the roasting machine needs to be done to minimize heat energy loss in the machine. The purpose of this study was to test the performance of a rotary drum coffee bean roaster with the addition of an insulator. The data that needs to be measured and calculated from this roasting machine is the temperature of the roasting room, the demand for electrical power and the loss of roasting energy. It is also important to know the moisture content of the coffee beans before and after roasting. The temperature of the roasting room reaches the range of 113oC to 140oC. The power required is 2.565 watts for 50 minutes of roasting. The roasting energy loss is relatively small, about 0.36 MJ. It can be concluded that the addition of an insulator can reduce energy loss.
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Lu, Zhiqin, and Julie M. Rowlett. "One can hear the corners of a drum." Bulletin of the London Mathematical Society 48, no. 1 (December 15, 2015): 85–93. http://dx.doi.org/10.1112/blms/bdv094.
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Holmgren, Sverker, Stefano Serra-Capizzano, and Per Sundqvist. "Can One Hear the Composition of a Drum?" Mediterranean Journal of Mathematics 3, no. 2 (July 2006): 227–49. http://dx.doi.org/10.1007/s00009-006-0074-x.
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Spirin, Anatolii, Igor Tverdokhlib, and Mykhailo Zamriі. "DETERMINATION OF THE MODE OF FUNCTIONING OF THE CENTRIFUGAL-GRAVITATIONAL SEPARATOR OF THE GRINDING DEVICE." Vibrations in engineering and technology, no. 3(102) (September 28, 2021): 64–71. http://dx.doi.org/10.37128/2306-8744-2021-3-7.
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The peculiarity of harvesting legumes is the need to process their heap on grater devices with subsequent separation. To improve the technical and economic performance of seed heap processing equipment, it is advisable to combine wiping and separation operations by combining a grater working body and a separating rotating sieve of cylindrical or conical shape. The analysis of influence of geometry of rotary sieve drums allows to define the rational form and parameters of work of the separating device which will provide the necessary quality of seed material. Analysis of the literature on the processes of sieve separation of grain and seed mixtures showed the advantages of centrifugal separators with a rotating sieve surface. Improving the efficiency of separation of mixtures by rotary sieves is achieved by the simultaneous use of centrifugal, Coriolis and gravitational forces. The aim of the study is to increase the efficiency of separation of seed heaps of legumes after treatment with a grater device by determining the trajectory of the seeds along the rotational surfaces. Earlier, the authors developed a grater-separating unit in which a cylindrical perforated drum is used to remove unworn seeds. This design does not use the surface of the sieve effectively enough. To increase the uniformity of the load on the steaming surface of the rotary drum, it is advisable to reduce its area in the direction of seed movement. To do this, use a conical separating surface to reduce the radius of the cone in the direction of movement of the material. When considering the movement of a particle, it is represented as a material point with mass m moving along a conical surface that rotates around a vertical axis. As a result of theoretical researches the dependence which defines time of stay of a particle on a sieve depending on a coordinate (length of a generating cone) is received. A graphical interpretation of this dependence for certain values of design parameters is also presented. As a result of research, it was found that increasing the residence time of the material on the sieve due to the use of a conical surface increases the yield of pure seeds, and also contributes to the uniform loading of the sieve surface, which improves the quality of the source material.
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Reuter, Martin. "Can one hear shape?" PAMM 7, no. 1 (December 2007): 1011101–2. http://dx.doi.org/10.1002/pamm.200700694.
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Li, Tao, Lingtian Xie, Boyang Zhao, Wenran Shen, and Yun Liu. "Analysis on the Effects of Different Receiver Structures and Porous Parameters on the Volumetric Effects and Heat Transfer Performance of Porous Volumetric Solar Receiver." International Journal of Energy Research 2023 (February 7, 2023): 1–13. http://dx.doi.org/10.1155/2023/3289428.
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The volumetric solar receiver is an important heat transfer component of the concentrated solar power (CSP) system. Moreover, in order to improve the absorption of concentrated solar radiation, the porous media are widely used in volumetric solar receiver. In recent years, many studies were concerned with the effects of porosity, pore number density and size, Reynolds number, and Darcy number on heat and flow performance in volumetric solar receiver. However, there are few studies on the effects of structure type and geometric parameters on the volumetric effects and the radiation characteristics of a porous volumetric solar receiver with nonuniform heat flux boundary condition. In this contribution, in order to analyze the effects of structures on the volumetric effects and heat transfer performance, we design six types of porous volumetric receiver structures, whereas the volume of different structures keeps consistent. Then, we apply the local non-thermal-equilibrium model and also consider the effect of structure shape on the concentrating solar radiation transport characteristic. Furthermore, we apply the Gaussian distribution model (GDM) to simulate the actual nonuniform heat flux boundary condition. The result shows that drum-type structure (RT-III) has the best heat transfer performance among the six structures; e.g., the outlet average temperature of fluid is up to 851 K when the pore size and porosity of porous media are 2 mm and 0.7, respectively, which is 41 K increased than the scaled cone-type structure. In addition, the pore diameter has less influence on the outlet temperature of fluid, but it has greater influence on the pressure drop. The contribution can provide a reference for this type of solar receiver design and reconstruction.
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Baryshnikov, Yu. "Counting the Shape of a Drum." Advances in Applied Mathematics 17, no. 1 (March 1996): 101–16. http://dx.doi.org/10.1006/aama.1996.0005.
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Wang, Lei Gang, De Zhi Kong, Jia Yang He, and Yao Huang. "Study on Deformation Law of Drum-Shaped Blank and Collapse Defect in Rolling Process." Advanced Materials Research 941-944 (June 2014): 1682–87. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.1682.
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Based on the FEM software simufact.forming, a finite element model of the radial-axial ring rolling for one ring product was constructed and the rolling process under different drum-shaped blanks were simulated in this paper, which revealed the variation of drum-shaped blank in the rolling process, analyzed the formation process and further proposed measures of eliminating collapse defect. The results show that the drum disappearing rate in initial rolling stage is greater than in later stage and it becomes increasingly difficult to disappear, which leads to collapse defect in the end. The drum-shape can be reduced by greater radial feed in initial rolling stage in the case of small drum-shape or rounding before rolling on ring rolling machine in the case of large drum-shape for avoiding collapse defect. The results provide valuable guiding significance for practical production.
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Lin, Qi, and Lu Min Chen. "Particle Motion Simulation and Parameter Optimization Design in Drum Granulation." Key Engineering Materials 693 (May 2016): 174–81. http://dx.doi.org/10.4028/www.scientific.net/kem.693.174.
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Drum granulators are widely used in powder granulation industry, and particles’ sphericity is one of the important indexes of drum granulation quality. To improve the particle sphericity, it is necessary to study the influence of particle size and shape on particles’ motion of both attitude and trajectory in the drum. This paper presents a mixed method of the discrete element simulation, orthogonal design experiment and mathematical statistics to investigate the influencing factors of particle orientation. The study found that there is a certain effect of particle shape, size and the speed of the drum on the particle orientation. According to the range analysis, it can be concluded that the effect of the three factors on the particle orientation is in the order of particle shape > particle size > the speed of the drum. Optimum combination was observed to be particle shape, size, and the speed of the drum are homogeneous ellipsoidal particles, 3 mm and 40 rpm, respectively. The study will facilitate to optimize the granulation process parameters.
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Wen, Xue, Jian-ping Tan, Su-qi Liu, and Xin-he Li. "Research on monitoring method for thinning spinning process of the ultra-thin-walled cylinder based on the drum shape." Science Progress 103, no. 1 (October 10, 2019): 003685041987772. http://dx.doi.org/10.1177/0036850419877727.
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In order to perceive the state of the process of reverse thinning spinning of the ultra-thin wall tube, a monitoring method based on drum shape is proposed. The method uses the non-uniform rational basis spline curve fitting method based on the moving least squares method to reconstruct the outer contour data of the spinning zone collected by the line laser displacement sensor and extracts the outer contour curve of the drum zone according to the spinning characteristics. Then, the dynamic time warping algorithm is used to analyze the similarity between the current and previous drum curves in order to judge whether the current spinning state is abrupt or not. At the same time, the current spinning state is judged by combining the curvature comb of the drum curve, the number of convex areas of the drum curve, the drum ratio, and the drum change trend. Finally, the drum shape detection and the spinning condition monitoring experiments are carried out. The experimental results show that this method can obtain the outer contour shape of the drum section at one time, and the accuracy is 0.05 mm with respect to the measured value of the three coordinates. The method can realize the visual monitoring of the abrupt change of the spinning process by judging the similarity of the drum curve at the adjacent time under different spinning states. In the state of instability, the curvature comb of the drum curve is discontinuous, the curve is G0 continuous, the drum ratio exceeds the critical drum ratio 2.0, and there is more than one convex region, which realizes the monitoring of spinning state more accurately. The experimental results verify the correctness of the proposed method and prove that the method can be used as a new method to judge the stability of the ultra-thin-walled cylinder spinning process.
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Ijaz, N., Ahmed Zeeshan, and S. U. Rehman. "Effect of electro-osmosis and mixed convection on nano-bio-fluid with non-spherical particles in a curved channel." Mechanics & Industry 19, no. 1 (2018): 108. http://dx.doi.org/10.1051/meca/2017040.
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This paper resigns to study effects of electro-kinetic force due to presence of electrical charge layer on the walls of the channel. The nano-bio-fluid fills the void between two concentric curved plates. The flow is induced due to peristaltic wave on flexible walls. The effects of mixed convection along with heat transfer are accounted. Furthermore, the focus is on effects of shapes of non-spherical nanoparticles in nano-bio-fluid and its effects on the flow. Nanofluids are important in treatment of cancer and other diseases in tissues which are normally not reachable by normal drug procedures. The problem is modeled for four types of non-spherical nanoparticles of alumina in aqueous base fluid. Numerical solution is obtained using Mathematica. Some important results are displaced through graphs. Empirical observations display that a significantly greater velocity for nanofluid with blade shape particles is offered followed by brick shaped particles. Numerical experiment also deems a rise in heat transfer due to presence of blade shapes particles.
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Yang, Jiapeng, Hua Zeng, Tongqing Zhu, and Qi An. "Study on the dynamic performance of concrete mixer's mixing drum." Mechanical Sciences 8, no. 1 (June 16, 2017): 165–78. http://dx.doi.org/10.5194/ms-8-165-2017.
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Abstract. When working, the geometric distribution shape of concrete in concrete mixing truck's rotary drum changes continuously, which cause a great difficulty for studying the dynamic performance of the mixing drum. In this paper, the mixing system of a certain type of concrete mixing truck is studied. A mathematical formulation has been derived through the force analysis to calculate the supporting force. The calculation method of the concrete distribution shape in the rotary drum is developed. A new transfer matrix is built with considering the concrete geometric distribution shape. The effects of rotating speed, inclination angle and concrete liquid level on the vibration performance of the mixing drum are studied with a specific example. Results show that with the increase of rotating speed, the vibration amplitude of the mixing drum decreases. The peak amplitude gradually moves to the right with the inclination angle increasing. The amplitude value of the peak's left side decreases when tilt angle increases, while the right side increases. The maximum unbalanced response amplitude of the drum increases with the decrease of concrete liquid level height, and the vibration peak moves to the left.
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Zhang, H. B., L. Zhou, and Ying Xue Yao. "Dynamic Balance Analysis of Drum-Shape Rotor." Applied Mechanics and Materials 10-12 (December 2007): 909–12. http://dx.doi.org/10.4028/www.scientific.net/amm.10-12.909.
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For rigid rotor that widely applied in gyroscopes, high precision dynamic balance is very important. The paper introduces a dynamic balance method for drum-shape gyroscope rotor: the rotor is supported by gas bearing; detecting the displacement of three points on the drum-shape rotor’s end-plane, obtaining its normal direction. Then according to geometrical relation of geometric axis and polar inertia axis, the dynamic trace of the rotor can be obtained, and the rotor’s mass imbalance is calculated. Experiment result shows that the method has high balance accuracy, particularly suit for high-speed gyroscope rotor whose mass imbalance is small.
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Kesavan, S. "Listening to the shape of a drum." Resonance 3, no. 10 (October 1998): 49–58. http://dx.doi.org/10.1007/bf02841422.
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Kesavan, S. "Listening to the shape of a drum." Resonance 3, no. 9 (September 1998): 26–34. http://dx.doi.org/10.1007/bf02836078.
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Asif, Mohammad, Kamlesh Chandra, and Prabhu Shankar Misra. "Wear Characteristic of Al-Based Metal Matrix Composites Used for Heavy Duty Brake Pad Applications." Materials Science Forum 710 (January 2012): 407–11. http://dx.doi.org/10.4028/www.scientific.net/msf.710.407.
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Wear study of metal matrix composites used as friction material is one of the most important parameter for determining the brake performance. The present investigations relates to the development of Aluminum powder based brake pads; where the back plates are also made of Aluminum based powders respectively. Thus it is aimed to fabricate net-shape Aluminium powder based brake pads in a single forming operation with better characteristics (low wear, low temperature rise, stable coefficient of friction) employing a newly developed technology namely “Hot Powder Preform Forging” technique. Three Aluminum based friction composites which are designated as ALM 01, ALM 02 & ALM 03 were formulated. The dry wear test is carried out using a pin-on-disc tribo-tester at constant sliding speed of 9 ms-1 under a load of 50 N. The counter face disc is made of heat treated grey cast iron. During the test, the cumulative wear (gm), Coefficient of friction, temperature rise (oC) and noise level (dB) were recorded. The effect of load at constant speed on sliding wear, frictional characteristic of aluminum based MMC (rotor / drum) in dry condition is studied. On the basis of initial laboratory tests like density, Hardness, wear test, the samples were qualified for sub-scale dynamometer test at Rejected Take Off condition. Optical microscope was used to investigate the microstructure of metal matrix friction composites surfaces. The results revealed that coefficient of friction was more stable. The Cumulative wear (gm) was low with rise in temperature. It was also observed that distribution of ingredients in matrix was fine and homogeneous.
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Ma, Liu Xuan, Ya Qin Li, Yi Yuan Ge, and Yang Yang Han. "The Design and Research on Spreading Soil Device of Rice Factory Seedlings." Advanced Materials Research 694-697 (May 2013): 3136–40. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.3136.
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The spreading soil device of rice factory seedling has been designed. In study the V shape bulldozing plate drum dump structure has been designed that focused on the high quality requirements of the super rice seedlings, the diameter and length of the V shape bulldozing plate drum dump and the thickness M of the V shape bulldozing plate has been designed, a force model of the soil in the dumping course and analyze the effect of spiral and operate width of the V shape bulldozing plate to dump performance also has been established. Finally, the assembled reasonableness between the drum dump and other components has been established through the 3D solid modeling of Pro / E software. The thickness and uniformity of spreading soil has been guaranteed also the quality of seedling emergence has been ensured by designing the device.
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Amore, P. "Can one hear the density of a drum? Weyl's law for inhomogeneous media." EPL (Europhysics Letters) 92, no. 1 (October 1, 2010): 10006. http://dx.doi.org/10.1209/0295-5075/92/10006.
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Ning, Bo, Xiang Luo, Ye Feng, Xiao Chen, and Li Jun Wu. "Study on Total Pressure Losses Characteristics of Rotating Cavity with Radial Inflow of Different Drum Hole Shape." Advanced Materials Research 663 (February 2013): 483–89. http://dx.doi.org/10.4028/www.scientific.net/amr.663.483.
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The pressure losses characteristics of the rotating cavity with radial inflow were investigated by testing method. The rotating cavity with oblong and round drum holes inlet and outlet total pressure under different operational state were tested, the influence of non-dimensional mass flow rate and rotating Reynolds number on rotating cavity with a Radial Inflow of different drum holes were analyzed. The results show that total pressure losses of the rotating cavity increases with the rotating Reynolds number and flow coefficient. Structure with oblong drum holes is superior to structure with round drum holes with lower total pressure losses in the range of the ratio of the flow coefficient and the Reynolds number is less than 0.048.And structure with round drum holes is superior to structure with oblong drum holes with lower total pressure losses in the range of the ratio of the flow coefficient and the Reynolds number is less than 0.048.
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Preud’homme, Nicolas, Eric Opsomer, Nicolas Vandewalle, and Geoffroy Lumay. "Effect of grain shape on the dynamics of granular materials in 2D rotating drum." EPJ Web of Conferences 249 (2021): 06002. http://dx.doi.org/10.1051/epjconf/202124906002.
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We experimentally investigate the effect of the grain shape on the flow of granular material. The grain shape is modified to highlight the effect of grain circularity on granular flow in a 2D rotating drum. Using a laser cutter, we create particles with decreasing circularity. We observe that the effect of grain shape depends on the rotation speed of the drum. For high rotation speed, granular flow is influenced by the packing’s dilatancy whereas, at low rotation speed, packing fraction seems to influence flowing dynamics. We link these two measurements to grain shape in order to explain its effect on granular flow.
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Glasauer, F. U., and I. Müller. "Drum- and -Disc-Engine with Shape Memory Wires." Le Journal de Physique IV 06, no. C1 (January 1996): C1–301—C1–307. http://dx.doi.org/10.1051/jp4:1996129.
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Gutkin, Boris, and Uzy Smilansky. "Can one hear the shape of a graph?" Journal of Physics A: Mathematical and General 34, no. 31 (July 27, 2001): 6061–68. http://dx.doi.org/10.1088/0305-4470/34/31/301.
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Valette, Alain. "Can one hear the shape of a group?" Rendiconti del Seminario Matematico e Fisico di Milano 64, no. 1 (December 1994): 31–44. http://dx.doi.org/10.1007/bf02925188.
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Zastempowski, Marcin, and Andrzej Bochat. "Research Issues in the Process of Cutting Straw into Pieces." Sustainability 12, no. 15 (July 31, 2020): 6167. http://dx.doi.org/10.3390/su12156167.
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Comparative studies of the classical and new design of a chaff cutter’s cutting drum have been conducted within the frames of the study in order to determine their functional characteristics at the time of cutting rye straw into pieces of specific length (into chaff). A classical design of a cutting drum is of the shape of a roller and is suitable for material layer cross-cutting. However, the new drum design has the shape of a double truncated cone and, with the use of it, diagonal cuts in two directions can be realized. The studies were conducted for four designs of cutting drums with cutting angles α = 0° (classical design) and α = 15°, α = 30°, and α = 45° (new design). Three indicators were applied for the assessment: capacity, unit energy consumption, and the unit cutting resistance. The obtained results show that the use of a new drum design makes it possible, depending on the assumed parameters of the cutting process and the material’s compaction degree, to increase the process’s efficiency by up to 25%, lower the unit energy consumption up to 34%, and lower the unit cutting resistance by up to 8%. The conducted experimental studies have unequivocally shown that the use of a new cutting drum design, as compared to the classical one, results in a considerable increase in the cutting process’s performance. Studies on the new design of a chaff cutter’s cutting drum, of the shape of a double truncated cone, belong to original ones that so far have not been described in the available literature.
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Choi, Hye Jin. "The History of Traditional Pansori and The Prospects for The Development of Performance." Liberal Arts Innovation Center 9 (November 30, 2022): 225–48. http://dx.doi.org/10.54698/kl.2022.10.225.
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In modern pansori, various experiments are being made on the existing traditional pansori, and many new creations of pansori are being made. However, traditional pansori also has historically undergone continuous changes and experiments. In this regard, this study was intended to suggest the point where the traditional pansori has changed and the tasks to be positively improved by the pansori of our time.
First, the performance aspects of traditional pansori were analyzed in a visual dimension. This study examines how pansori performances have changed from the mid-19th century to modern pansori. In the 19th century, in the yard, a singer performed wearing a hat on an applicator, and held a white or red fan. The drummer used a relatively large drum, and the tip of the drumstick was round. At the end of the 19th century, in Kim Jun-geun's paintings, it can be seen that the performance space for pansori has changed into a room or an indoor space. The singer performed with the master, but did not organize a separate space, and the drum and drummer of the master was changed to a shape similar to that of modern times. In the early 20th century, the stage of pansori during the Japanese colonial period was transformed into a theater. The traditional attire of the singer and the master was sometimes simplified with a bob and a duruma. In particular, female singers changed from wearing a white hanbok with their indigo hair to gradually wearing a splendid hanbok. As the intangible cultural heritage system began after the 20th century, pansori centered on human cultural assets was mainly performed on stage under the technical influence of microphones and lighting. It can be said that the musicality of pansori has gradually become highly sophisticated amid these changes in performance space and media.
While traditional pansori could be changed over time without losing its typicality, there were also parts that lost the essence of 'pan'. This is the weakening of storytelling or polarity, and in this regard, the development direction of traditional pansori was suggested in three areas. First of all, I heard that aniri(아니리) and wit should be strengthened to restore the storytelling of pansori. Next, it was argued that the spirit of the times should be contained through the creation and reconstruction of a new lyric(더늠). Finally, it was suggested that the dramatic aspect of pansori should be established through the expansion of neoreumsae(너름새) and reinforcement of acting.
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De, Debarati, and Madhuri Mandal Goswami. "Shape induced acid responsive heat triggered highly facilitated drug release by cube shaped magnetite nanoparticles." Biomicrofluidics 10, no. 6 (November 2016): 064112. http://dx.doi.org/10.1063/1.4971439.
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Воляник, О. Ю. "ДОСЛІДЖЕННЯ ВЗАЄМОДІЇ РОБОЧИХ ОРГАНІВ БАРАБАНА ВІДЦЕНТРОВОЇ МАШИНИ З ОБРОБЛЮВАНИМ МАТЕРІАЛОМ." Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 150, no. 5 (May 31, 2021): 14–23. http://dx.doi.org/10.30857/1813-6796.2020.5.1.
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Carrying out of analytical research of interaction of operation device of a drum with materials in the centrifugal car for processing of products of the light industry. Determining the dependences and significant parameters of the operation devices that affect the nature of the movement of processed materials in the drum. Methodology. Methods of mathematical study of geometrical parameters of operation devices of the centrifugal machine and their influence on character of movement of the processed material in a hydroextractor drum are used. Results. An analytical study of the interaction of the operation devices of the drum with the material in a centrifugal machine for processing light industry products using methods of mathematical analysis of the geometric shape of the side surface. This method is based on the principle of detecting patterns of motion of material points in the plane of the side surface of the operation device of the drum of the centrifugal machine. The validity of the conclusions of the study on the example of the characteristics of the surface of the operation device of the helical shape is proved. Scientific novelty. The parameters and indicators that must be taken into account when studying the interaction of the operation devices of the drums of centrifugal machines for processing light industry products are analyzed and presented. Practical significance. As a result of the analytical study, the shape was considered and the most significant geometrical parameters of the operation device of the centrifugal machine were determined, which determine the nature of the movement of the processed material in the hydroextractor drum. The obtained dependences and conclusions can be used in the design of the operation devices of centrifugal drum machines for processing various materials in light industry. The information presented in the article is of interest to scientists who study the problems of processing and interaction of materials and mixtures in rotary centrifugal systems, is of practical importance for engineers in mechanical engineering, instrumentation, consumer services, technologists of food, light, chemical and others.
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Kim, Junhyong, Elchanan Mossel, Miklós Z. Rácz, and Nathan Ross. "Can one hear the shape of a population history?" Theoretical Population Biology 100 (March 2015): 26–38. http://dx.doi.org/10.1016/j.tpb.2014.12.002.
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Gordon, Carolyn S. "When you can’t hear the shape of a manifold." Mathematical Intelligencer 11, no. 3 (June 1989): 39–47. http://dx.doi.org/10.1007/bf03025190.
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