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15компоновки лучей.
Исходя из максимальных результатов на глубину закалки можно сделать вывод, что закалять возможно детали абсолютно любой номенклатуры и габаритов, учитывая, что максимально допустимый износ любой детали составляет не более 0,4-0,5 мм (в зависимости от детали и от её условий работы).
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acoustic comfort of a multipurpose hall palace of culture for university students of bstu named after v. g. shukhov
Tarasenko V. N., Ph. D. (Tech. Sciences), Asst. Prof., Degtev I. A., Ph. D. (Tech. Sciences), Prof., Chernysh N. D., Asst. Prof.
Belgorod State Technological University named after V. G. Shukhov.
ABSTRACT
Acoustics of multipurpose halls is made up of a number of factors, the most important of which is considered to be the geometry of the Hall itself, the existence of balconies and other constructive techniques of division of the Hall's space, the kind of decoration of interior elements, features of sound reproduction equipment placement, availability and type of sound absorptions (silencers).
Keywords: comfort of staying, sound absorption, electro-acoustic systems, equivalent areas of sound absorption of materials and structures.
A hall for cultural events is a complex, high-technical structure, elements of which are related to the functional accomplishment. Acoustic accomplishment plays an important role in ensuring the comfort of the audience. Acoustics is considered to be good, if the multipurpose hall is suitable for events of various kinds, with accented useful sounds and the extraneous ones are reduces to the level that does not interfere with the comfort of perception.
Acoustic comfort of a hall consists of the following components:
-provision of the audience with sufficient sound energy; -creation of the diffuse sound field; -exclusion of ECHO and focus of the sound; -provision of optimum reverberation time; -minimization of extraneous noise.
Assessment of a hall, where the sound of music and of speech is recognized as of the highest quality, is based on laws of distribution of sound waves in a closed room (space), on laws of reflection and absorption of sound by different kinds of surfaces. Acoustic comfort involves balance between the processes of absorption and reflection of sound energy.
Placement of sound reproduction equipment is involved for conducting various types of sound programs in multipurpose halls. The sound reproduction equipment enables changing the acoustic properties of the premises depending on the type of the programs. For playing different genres of music, halls with different acoustic settings are required. Different acoustics on the stage and in the area of the audience should be provided within one hall. Rooms which are equipped with sound system (insonation systems), are divided into two groups:
1) halls, in which viewers perceive sound directly from the stage and with the help of amplification (lecture halls, concert halls, multipurpose halls);
2) halls, in which viewers perceive sound using only audio system.
In lecture halls and theatrical halls are designed to enhance the sound reinforcement system for speech; when performing concert programs soloists need sound reinforcement, when the soloists are accompanied by orchestra. In both cases, the microphone receives the signal for further amplification and is situated in the soundfield of loudspeakers, emitting amplified signal to the audience, thus, the amplification system is a system with acoustic feedback.
Usually for amplification of concert programs and soloists in large halls people use multi-channel stereo system, which allows obtaining high quality strengthening and preservation of acoustic spatial pattern. Traditionally multi-channel amplification system is applied. On the input side of each channel there is a group of microphones. Signals get the loudspeakers and then the audience from microphones after amplification. Signal which is received by the microphone, closest to the source, has a higher level compared to the signals received by other microphones. In addition, the first signal goes ahead in comparison with the others in time. This ratio level and temporal shifts persists in the signals emitted by loudspeakers that create the desired stereo effect. Loudspeakers of the central channel are usually above the middle part of the portal scene, and loudspeakers of the side channels are placed on the edges and below the loudspeakers of the central group.
In the halls of multi-purpose you must manage your time
and frequent characteristic of reverb. Despite amplification of sound acoustic systems can serve as the reverb of time control (ambiophony systems).
The choice of the acoustic equipment, locations of microphones and loudspeakers, correction of the frequent characteristic of strengthening is carried out taking into account the hall architectural planning solution. Quality of the sound first of all depends on geometrical parameters of the room. The form, the size, the volume, the hall capacity, the arrangement of architectural and interior elements allow to solve considerable part of problems of creation of the diffusion sound field and the ratio of the reflected and direct sound energy arriving to listeners.
The direct sound wave has bigger value in the halls equipped with acoustic systems. Mobile reflectors, rising curtain-draperies, sliding partitions, rotating screens which have various sound absorption on the external and back parties, the devices intended for change of volume of the room are used for regulation of characteristics of the sound field. For example, for change of volume of the hall, application of an orchestral (acoustic) sink/shell is possible that, undoubtedly, gives the following advantages:
- the device of a folding sink allows to use the hall for concert programs, performances;
- the separation of a sink from the hall is reached by lowering of the screen and the change of arrangement of reflectors on walls and ceiling;
- accession of volume of an orchestral sink to the volume of the hall allows to increase reverberation time at average frequencies on 0,2 s;
- the protecting surfaces of the sink provide the required structure of early reflections, etc.
Acoustic properties of the room can change considerably the nature of sounding of the best acoustic system.
An important parameter of acoustics of a room is considered to be diffusion of the sound field which characterizes uniformity of distribution of energy of the reflected waves. The required diffusion of the sound field in multipurpose halls is reached in various ways. For example, walls and ceiling can be dismembered by separate surfaces, located in different planes and under different corners so that the frequency characteristics of sound energy cannot be distorted. At the same time, the less area of the reflecting surface is, the better. However, smooth surfaces interfere with creation of necessary diffusion
of the sound field. Existence in the room of parallel surfaces with high reflecting ability leads to formation of series of fast repetitions of the sound signal (the flitting echo). The deviation from parallel walls at 2...3° or from one wall at 5...6° weakens formation of the flitting echo. Placement on surfaces of sound-absorbing or disseminating materials, for example, of acoustic "Sonex" foam, material like a thin carpet of "Masonit'oM" or "Flutter Stix" allows eliminating this phenomenon. Round and oval surfaces, columns, pilasters, niches and additional architectural elements increase diffusion because such surfaces create the scattered (not directed) reflection.
In cases when it is impossible to change design features of the hall, placement of the semi-cylindrical deflectors made of plywood, plaster or of polyurethane foam allows eliminating the repeating echo.
The significant acoustic parameter of the hall is the reverberation time which is necessary in order that intensity of the sound after cancellation of its source has decreased to one million share of the initial size. The reverberation, formed by a set of sounds which are imposed one on to another one or follow one by one, extends the direct sound after his termination and interferes with its correct perception. Reverberation shouldn't be too short or too long: at long reverberation syllables in words become indistinct.
An important condition for obtaining good audibility and legibility of speech is functional ability of the material to absorb sound. At design of halls pay much attention to the choice of material of building constructions. For example, introduction of wooden elements of designs as the main material creates special acoustic conditions in halls. Broad development of new materials allows using more economic and fireproof decisions. Now for finishing decoration we often use the material Basotect (Russian name "Ekhokor"), production of the Basf Company, possessing good sound-absorbing ability, high fire resistance (G-1) and presentable appearance.
Inspection of acoustic improvement and the invoice of decoration of sound-absorbing surfaces in the hall at the Palace of Culture at BSTU named after V. G. Shukhov is carried out for the purpose of assessment of sound-absorbing ability of elements of the hall interior (fig. 1) and the definition of possibility of replacement the elements of ceiling systems without change of basic sound reflecting characteristics on more modern facing materials.
Figure 1. Interior elements in the multi-purpose hall of the Palace of Culture at BSTU named after V.G. Shukhov.
Considering the areas of sound absorption and the invoice of materials, approximate coefficients of sound absorption at average geometrical frequencies (table 1) have been calculated.
For halls of universal purpose calculation of time of reverberation is usually made for compound frequencies by 125, 500 and 2000 Hz.
Table 1
The calculated value of the reverb time in the multi-purpose hall
Rationing frequencies, Hz Total area S, m2 a ф Reverberation time T, s
125 2766,46 0,133 0,25 2,073
500 0,155 0,30 1,728
2000 0,192 0,42 1,234
Average time of reverberation, s 1,678
Estimated time of reverberation (1,678 s) differs from normalized values [17] no more, than at 10 %. Thus, for ceiling system it is recommended to use materials which have sound absorption coefficient, comparable with the provided coefficient in tab. 1.
For exception of repeated reflections from walls and ceiling, and for exception of decrease in probability of emergence of undesirable resonances, there is a possible increase in coefficient of sound absorption for some surfaces by means of IJO 09
Уровень звукопоглощения
acoustic panels Ekhokor [18] which are represented by modern synthetic material — foam melamine. It possesses good soundproof characteristics, especially in the range of average and low frequencies from 500 to 1000 Hz (fig. 2), and it meets the international standards of fire safety. It is firm to very high temperatures for a long time (up to 240 °C), it doesn't melt, and it doesn't form burning drops at contact with flame. At the same time panels can be painted (or be applied with prints) for harmonious installation into the existing room interior.
1000
H50 4om 5000
100 135 160 TOO J50 Ï1S 400 500 fvKl
Figure 2. Sound absorption coefficient as BASOTECT® G depending on material thickness according to the ISO 10534-2 standard (impedance pipe) [18].
Good acoustic situation can't be seen or touched — it can only be felt. At the same time acoustics can be regulated. The solution of the existing acoustic problems in rooms demands not only effective absorption of sound, but also the minimum weight of acoustic materials. Sound-absorbing materials are intended to relieve hearing of interference of sound, rumble at low frequencies, background noise, resulting from reflections of sound from walls, beams of overlap pings and other surfaces.
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2. CH 2.2.4/2.1.8.562-96. Noise at workplaces, in rooms of residential, public buildings and on the territory of housing estates. M. 1996. p. 8.
3. State Standard Certification (SSC) 12.1.036-81 (CT SEV 2834-80). Occupational safety standards system. Noise. Admissible levels in residential and public buildings. M.: Publishing house of standards. 2001. p. 6.
4. SSC 31296.2-2006 (ISO 1996-2:2007). Noise. Description, measurement and assessment of noise. Part 2. Determination of levels of sound pressure. M.: Publishing house of standards. 2008, p. 22.
5. Y.V. Denisova, V.N. Tarasenko. Soundproofing of dwelling and office premises // Education, science, production and
management. Belgorod: BSTU. 2011. p. 15 - 17.
6. V.N. Tarasenko, L.N. Solovyov. Problems of sound insulation in residential construction // Vestnik of the Belgorod State Technological University named after V.G. Shukhov. 2013. № 4. p. 48 -52.
7. R.V. Lesovik, L.N. Botsman, V.N. Tarasenko. Enhancement of sound insulation of lightweight concrete based on nanostructured granular aggregate // ARPN Journal of Engineering and Applied Sciences, № 10. 2014. p. 1789 -1793.
8. V.N. Tarasenko, I.A. Degtev. Sound insulation of protecting designs // Priority scientific directions: from theory to practice: collection of XIV scientific conference. Novosibirsk. 2014. p. 143 - 148.
9. V.N. Tarasenko. Design of noise protection constructions // High-tech innovations: Collect ion of research and scientific conf, devoted to 60 th-anniversary of BSTU named after V.G. Shukhov (XXI scientific readings). Belgorod: BSTU. 2014. p. 115 -117.
10. I.V. Vasiliev. Overview of multi-channel systems of acoustic correction // Young scientist. 2016. № 5.
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15. A.G. Boganik. New materials for acoustic comfort // Construction technology. 2010 № 4 (73). p. 64 - 67.
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18. http://echocor.ru/articles/v_zone_akusticheskogo_ komforta/
оксидно кобальтовый титановыи электрод для
электрохимического синтеза гипохлорита натрия
Тульский Г.Г.
доктор технических наук, профессор Диаб Хассан аспирант Сенкевич И.В.
кандидат технических наук, доцент Тульская А.Г. кандидат технических наук, асистент Национальный технический университет "Харьковский политехнический институт, г. Харьков
OXIDIZED COBALT-TITANIUM ELECTRODE FOR ELECTROCHEMICAL SYNTHESIS OF SODIUM HYPOCHLORIDE
Tulskiy G.G. Doctor of technical sciences, professor
Diab Hassan Post-graduate student
Sinkevich I.V. Candidate of technical sciences, associate professor
Tulskaya A.G. Candidate of technical sciences, assistant National technical university "Kharkov polytechnic institute", Kharkov, Ukraine
АННОТАЦИЯ
Разработан малоизнашиваемый анод для электрохимического синтеза водных растворов гипохлорита натрия. Электрод состоит из токопроводящей титановой основы с каталитически активным покрытием из смеси оксидов кобальта и титана (ОКТП). Установлено, что при плотности тока 1000 Ам2 перенапряжение выделения хлора на ОКТП оставляет 40...45 мВ, т.е. каталитическая активность ОКТП сравнима с активностью ОРТА. Показано, что при концентрации хлоридов ниже 50 гдм-3 каталитическая активность ОКТП превышает ОРТА.
ABSTRACT
A dimensional stable anode (DSA) for electrochemical synthesis of sodium hypochlorite was developed. It consists of conductive titanium base coated by catalytic active layer of cobalt and titanium oxides mixture (Co3O4/TiO2). It was determined that at current density 1000 Am-2 the over potential of chlorine reaction was about 40...45 mV, so the catalytic activity of Co3O4/TiO2 is in the close juxtaposition with DSA coated by ruthenium and titanium oxides. It is shown that when the concentration of chloride is below 50 gdm-3, the catalytic activity of Co3O4/TiO2 is higher than RuO2/TiO2.
Ключевые слова: малоизнашиваемый анод, гипохлорит натрия, электрохимического синтез, оксидное кобальтово титановое покрытие.
Keywords: dimensional stable anode, sodium hypochlorite, electrochemical synthesis, cobalt and titanium coating.
ВВЕДЕНИЕ. Растворы "активного хлора" нашли широкое применение при обеззараживании питьевых и про-мышленно-бытовых вод, предотвращения биообрастания систем оборотного водоснабжения, для нужд стерилизации, дезинфекции, отбеливания. Электрохимический способ получения растворов активного хлора электролизом водных растворов щелочных металлов позволяет организовать производство непосредственно на месте потребления и в нужных количествах. соотношение стандартных потенциалов выделения хлора и кислорода из водных растворов хлоридов обуславливает применение анодных материалов с высокой их селективность в реакции выделе-
ния хлора. Промышленное производство хлора основано на применении малоизнашиваемых анодов с каталитическим покрытием на основе К.и02 или еще более дорогого 1г02. Однако, в последнее время постоянно снижающийся спрос на газообразный хлор и пропорционально увеличивающийся на растворы "активного хлора" требует разработки доступных малоизнашиваемых анодов. В том числе и для электролиза разбавленных растворов (менее 50 г-дм-3) хлоридов. Использование при таких концентрациях анодов на основе К.и02 или 1г02 неэффективно. Поэтому исследования, направленные на выяснение возможности использования для электролиза хлоридных
