scholarly journals THE PHILOSOPHY OF DRAWING

Author(s):  
Mikhail Verholantsev

Drawing is a peculiar phenomenon of human civilization. This inexhaustible engine of progress usually seems to us as a kind of study, as a preparation for a painting or a sculptural work. This essay proposes to look at drawing as a graphic reflection of fantasy, project and intention, a reflection of firm knowledge or doubt and skepticism, and, finally, offers to look at drawing as a method of studying life. The article provides a brief overview of the stylistic metamorphoses of European drawing, which occurred naturally or by chance. A person who always draws consciously composes, and his composition involuntarily reflects the scheme of the universe, drawn up in the artist's head based on his or her life experience. Every person has this experience, this worldview, this self-professed philosophy, but only a draftsman can show it. Collecting drawings is the most difficult and most impressive of all types of collecting. A drawing-lover discovers the whole world, the most accurate description of the given period of civilization. Since prehistoric times, civilization has been indebted to drawing. The rock drawing of primitive people reflects their vital desires and beliefs. Afterward, the wheel was designed; the steam engine, electricity, aeronautics were invented, space exploration began... and drawing and drafting accompanied all this. Teaching drawing in schools and universities is teaching the methodology of studying nature. From an early age, a person is taught to draw from life, and this is a visual study of an object. The teacher’s task is to show not only to sketch the visible outlines of an object but also to penetrate its structure, in other words, to prepare to fantasize and invent. Meanwhile, in schools and universities, it has become a custom to draw imitating photography as much as possible. Photography is the most democratic way of depicting; however, it is only a one-time, random image of an event. Drawing, on the other hand, accumulates several things. A metaphor, conclusion, knowledge, or ignorance, the struggle against victories and defeats, doubts, and confidence appear involuntarily in a drawing. Drawing is action, movement of thought, and religious beliefs, whereas photography is stagnant. However, it is precisely this stagnation, rigidity that is cultivated by fashionable modern artists. Moreover, adherents of photorealism develop the ridiculous coincidences so often found in photographs. Sculptors, architects, and jewelers make the most exciting drawings. Sculptors seem to see through an object, like an X-ray. They want to show volume on a plane. Architects imagine the organization of space and the interaction of volumes. All these aspirations, all these fantasies make drawing uniquely expressive and intelligent.

Author(s):  
Alon Banet ◽  
Rennan Barkana ◽  
Anastasia Fialkov ◽  
Or Guttman

Abstract The epoch in which the first stars and galaxies formed is among the most exciting unexplored eras of the Universe. A major research effort is focused on probing this era with the 21-cm spectral line of hydrogen. While most research focuses on statistics like the 21-cm power spectrum or the sky-averaged global signal, there are other ways to analyze tomographic 21-cm maps, which may lead to novel insights. We suggest statistics based on quantiles as a method to probe non-Gaussianities of the 21-cm signal. We show that they can be used in particular to probe the variance, skewness, and kurtosis of the temperature distribution, but are more flexible and robust than these standard statistics. We test these statistics on a range of possible astrophysical models, including different galactic halo masses, star-formation efficiencies, and spectra of the X-ray heating sources, plus an exotic model with an excess early radio background. Simulating data with angular resolution and thermal noise as expected for the Square Kilometre Array (SKA), we conclude that these statistics can be measured out to redshifts above 20 and offer a promising statistical method for probing early cosmic history.


Author(s):  
F. Nicastro ◽  
J. Kaastra ◽  
C. Argiroffi ◽  
E. Behar ◽  
S. Bianchi ◽  
...  

AbstractMetals form an essential part of the Universe at all scales. Without metals we would not exist, and the Universe would look completely different. Metals are primarily produced via nuclear processes in stars, and spread out through winds or explosions, which pollute the surrounding space. The wanderings of metals in-and-out of astronomical objects are crucial in determining their own evolution and thus that of the Universe as a whole. Detecting metals and assessing their relative and absolute abundances and energetics can thus be used to trace the evolution of these cosmic components. The scope of this paper is to highlight the most important open astrophysical problems that will be central in the next decades and for which a deep understanding of the Universe’s wandering metals, their physical and kinematical states, and their chemical composition represents the only viable solution. The majority of these studies can only be efficiently performed through High Resolution Spectroscopy in the soft X-ray band.


2018 ◽  
Vol 14 (S342) ◽  
pp. 29-36
Author(s):  
M. Guainazzi ◽  
M. S. Tashiro

AbstractX-ray spectroscopy is key to address the theme of “The Hot Universe”, the still poorly understood astrophysical processes driving the cosmological evolution of the baryonic hot gas traceable through its electromagnetic radiation. Two future X-ray observatories: the JAXA-led XRISM (due to launch in the early 2020s), and the ESA Cosmic Vision L-class mission Athena (early 2030s) will provide breakthroughs in our understanding of how and when large-scale hot gas structures formed in the Universe, and in tracking their evolution from the formation epoch to the present day.


2013 ◽  
Vol 78 (4) ◽  
pp. 579-590 ◽  
Author(s):  
Aleksandra Mitrovic ◽  
Miodrag Zdujic

Mechanochemical treatment of Serbian kaolin clay was carried out in a planetary ball mill using two different milling media, hardened steel or zirconia vials and balls. The samples obtained with various milling times were characterized by the particle size laser diffraction (PSLD), X-ray diffraction (XRD), differential scanning calorimetry/thermogravimetry (DTA/TGA) and Fourier-transform infrared (FTIR) analyses. Mechanochemical treatment induced amorphization of the kaolinite phase accompanied by dehydroxylation. It was found that for the given milling parameters, amorphization mainly took place in the milling period up to 15 min, and was completed after about 30 min of milling for both milling media used. The pozzolanic activities were determined by the Chapelle method. Milling in the hardened steel milling medium had no significant influence on pozzolanic activity, even though there was accumulated iron contamination. For both milling media, pozzolanic activity of 0.79 was obtained for the samples milled for 15 min and it remained almost unchanged with prolonged milling. The determined pozzolanic activity values are close to these of commercial metakaolinite or metakaolinite obtained by the calcination of the same clay, therefore, indicating possibility for obtaining high reactive pozzolana by mechanochemical treatment of Serbian kaoline clay.


Nature ◽  
2001 ◽  
Vol 409 (6816) ◽  
pp. 39-45 ◽  
Author(s):  
Stefano Borgani ◽  
Luigi Guzzo

Author(s):  
I. Abbasov ◽  
M. Musayev ◽  
D. Askerov ◽  
J. Huseynov ◽  
E. Gavrishuk ◽  
...  

In the given paper, the temperature dependences ([Formula: see text]–300 K) of the green band intensity at wavelengths [Formula: see text] nm and [Formula: see text] nm have been measured and observed, respectively, from the polished and unpolished surface (PS and unPS) of a polycrystalline CVD (chemical vapor deposition) ZnSe sample upon excitation by X-ray quanta ([Formula: see text]. In both cases, the activation energy of thermal quenching has been determined, and the reasons for thermal quenching have been considered in detail. Along with XRL spectra analysis, the temperature behavior of the green band observed upon excitation by an ultraviolet (UV) laser (He–Cd, [Formula: see text] nm) from the PS and unPS in the temperature range [Formula: see text]–200 K has been discussed in more detail.


2014 ◽  
Vol 584-586 ◽  
pp. 894-898
Author(s):  
Ping Zhang ◽  
Guan Guo Liu ◽  
Chao Ming Pang ◽  
Bing Du ◽  
Hong Gen Qin

The X ray computed tomography (X-CT) was applied to test the cracking resistance of cement paste, and the hydration process was monitored to study the effect of fly ash on the early age cracking performance. The results showed that the hydration heat reduced with the increase of fly ash under the same water-cement ratio. Within 24h, the porosity increased with time. The addition of fly ash increased the proportion of large holes and then changed the internal stress state. Using X-CT test method and by comparing the number of cracks, the sample with 20% FA was found to have the most serious cracks, whereas the sample with 30% FA had the best crack resistance.


2014 ◽  
Vol 29 (4) ◽  
pp. 321-325
Author(s):  
Jovica Praskalo ◽  
Jasna Davidovic ◽  
Biljana Kocic ◽  
Monika Zivkovic ◽  
Svetlana Pejovic

In order to set up a successful mammography screening program in the Republic of Srpska, a Siemens Mammomat 1000 X-ray machine was selected for analysis as the said mammography system is widely used in clinical practice. The variations in tube parameters (specific air kerma, high-voltage accuracy and reproducibility, linearity between exposure and dose exposure time) were monitored over a five-year period, from 2008 to 2012. In addition, due to observed daily fluctuations for chosen parameters, a series of measurements were performed three times a day within a single-month period (mainly October 2012). The goal of such an experimental set up is to assess short-term and long-term stability of tube parameters in the given mammography unit and to make a comparison between them. The present paper shows how an early detection of significant parameter fluctuations can help eliminate irregularities and optimize the performance of mammography systems.


BIBECHANA ◽  
1970 ◽  
Vol 6 ◽  
pp. 27-30
Author(s):  
Devendra Adhikari ◽  
Krishna Raj Adhikari

Different physical phenomena, techniques, and evidences which give the proof for the existence of dark matter have been discussed. Keywords: Baryonic matter; dark matter; Chandra x-ray ObservatoryDOI: 10.3126/bibechana.v6i0.3936BIBECHANA Vol. 6, March 2010 pp.27-30


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