scholarly journals Valve converter with steeply falling external characteristics

2019 ◽  
Vol 516 ◽  
pp. 012055
Author(s):  
S Mendybayev ◽  
T Akimzhanov ◽  
S Zhumazhanov ◽  
Ye Sarsikeev
Keyword(s):  
Valve Converter ◽  
External Characteristics

scholarly journals Prediction and Evaluation of Waterjet Pump Performance under Nonuniform Inflow Using Parallel Compressor Theory

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Puyu Cao ◽  
Rui Zhu
Keyword(s):  
Flow Instability ◽  
Internal Flow ◽  
Weighted Sum ◽  
Pump Performance ◽  
Inlet Velocity ◽  
Inlet Distortion ◽  
Pump Head ◽  
Compressor Performance ◽  
Waterjet Pump ◽  
External Characteristics

Parallel compressor theory (PCT) is commonly used to estimate effects of inlet distortion on compressor performance. As well as compressor, the actual inflow to pump is also nonuniform and unfavorable for performances. Nowadays, insufficient understanding of nonuniform inflow effects on pump performance restricts its development. Therefore, this paper applies PCT to predict external characteristics and evaluate internal flow instability of waterjet pump under nonuniform inflow. According to features of nonuniform inflow, the traditional PCT is modified and makes waterjet pump sub-divided into two circumferential tubes owning same performances but with different inlet velocity (representing nonuniform inflow). Above all, numerical simulation has been conducted to validated the applicability and accuracy of PCT in head prediction of waterjet pump under nonuniform inflow, since area-weighted sum of each tube head (i.e., theoretical pump head) is highly consistent with simulated result. Moreover, based on identifications of when and which tube occurs stall, PCT evaluates four stall behaviors of waterjet pump: partial deep stall, partial stall, pre-stall and full stall. Furthermore, different stall behavior generates different interactions between head variation of each tube, resulting in a multi-segment head curve under nonuniform inflow. The modified PCT with associated physical interpretations are expected to provide a sufficient understanding of nonuniform inflow effects on pump performances.

scholarly journals Analysis of the Influence of Different Bionic Structures on the Noise Reduction Performance of the Centrifugal Pump

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 886
Author(s):  
Cui Dai ◽  
Chao Guo ◽  
Yiping Chen ◽  
Liang Dong ◽  
Houlin Liu
Keyword(s):  
Flow Field ◽  
Noise Reduction ◽  
Centrifugal Pump ◽  
Great Influence ◽  
Frequency Doubling ◽  
Sound Field ◽  
Internal Flow ◽  
Test System ◽  
Centrifugal Pumps ◽  
External Characteristics

The strong noise generated during the operation of the centrifugal pump harms the pump group and people. In order to decrease the noise of the centrifugal pump, a specific speed of 117.3 of the centrifugal pump is chosen as a research object. The bionic modification of centrifugal pump blades is carried out to explore the influence of different bionic structures on the noise reduction performance of centrifugal pumps. The internal flow field and internal sound field of bionic blades are studied by numerical calculation and test methods. The test is carried out on a closed pump test platform which includes external characteristics and a flow noise test system. The effects of two different bionic structures on the external characteristics, acoustic amplitude–frequency characteristics and flow field structure of a centrifugal pump, are analyzed. The results show that the pit structure has little influence on the external characteristic parameters, while the sawtooth structure has a relatively great influence. The noise reduction effect of the pit structure is aimed at the wide-band noise, while the sawtooth structure is aimed at the discrete noise of the blade-passing frequency (BPF) and its frequency doubling. The noise reduction ability of the sawtooth structure is not suitable for high-frequency bands.

THE COMPOSITION DEVELOPMENT AND TECHNOLOGICAL RESEARCH OF THE ANTI-SCAR ECTOIN GEL

2021 ◽  
pp. 216-221
Author(s):  
Mayorova A.V. ◽  
Sysuev B.B. ◽  
Sysueva Y.V.
Keyword(s):  
Colloidal Stability ◽  
Protective Action ◽  
Topical Therapy ◽  
Hydrophobic Effect ◽  
Drying Characteristics ◽  
Plastic Properties ◽  
Technological Research ◽  
Technological Characteristics ◽  
Long Time ◽  
External Characteristics

The development of new means for topical therapy and prevention of scar formation of moisturizing and protective action based on ectoin can be promising. The optimal form is hydrogels, because of their adhesive and plastic properties, easily distribution and remaining for a long time on the skin. The purpose of this study was the development of the composition and technological research of the gel with ectoin for the prevention of skin scars. To select the optimal gel-forming agents’ technological studies (external characteristics, drying characteristics and film quality on the skin and on model surfaces, skin moisture, pH, the active substance release, thermal and colloidal stability, rheological properties) of model samples based on gel-forming agents, used in protective and anti-scar creams carried out. The composition of polymers xanthan and sodium carboxymethyl cellulose selected, which has improved adhesion and moisturizing properties, to reduce the frequency of application and provide a prolonged effect. The optimal concentration of dimethicone to enhance the protective effect and enhance the hydrophobic effect selected. The technological characteristics of model samples of ectoin gel investigated: description, pH, thermal and colloidal stability, viscosity, microbiological purity. The results indicate that the gel has the necessary technological characteristics that determine its quality. Thus, as a result of technological research, the composition of the anti-scar ectoin gel was developed.

EVALUATION OF POSSIBILITIES TO IMPROVE RIGID BODIES

2020 ◽  
Vol 69 (1) ◽  
pp. 392-395
Author(s):  
N.M. Nurullayev ◽  
◽  
D.A. Turgunboyev ◽  
Ye.N. Zholdassov ◽  
◽  
...  
Keyword(s):  
Literature Review ◽  
Software Package ◽  
Scientific Research ◽  
Rigid Bodies ◽  
Robotic Arm ◽  
Electromechanical Devices ◽  
End Effectors ◽  
External Characteristics

Manipulators are used for various purposes in order to simplify tasks or reduce the risk of tasks that are considered impossible, dangerous or difficult for humans. The robotic arm can be equipped with various types of end effectors to perform a variety of tasks. Grips are one of the most commonly used tools for manipulators. This article discusses the analysis of modeling new robotic gripping fingers, based on models of gripping gross rigid bodies of manipulators. A literature review was conducted in the relevant branches of scientific research. The ability to minimize dimensions and masses, as well as the final cost of the product, using available materials and electromechanical devices, various sensors, is evaluated. The external characteristics that make the previously developed analogues ineffective are analyzed. Modeling was released using the SolidWorks software package.

scholarly journals Control of Valve Converters with Natural Current Characteristics

2018 ◽  
Vol 155 ◽  
pp. 01047 ◽  
Author(s):  
Sergazy Mendybayev ◽  
Yermek Sarsikeyev ◽  
Dameli Kapanova
Keyword(s):  
Reactive Elements ◽  
Electric Force ◽  
Current Characteristic ◽  
Current Converter ◽  
Characteristic Features ◽  
Current Characteristics ◽  
Valve Converter ◽  
Modulating Functions ◽  
Parametric Source

The article considers the valve converter with a natural current characteristic, which is called the current of parametric, for which the primary is not the source of the electric force but a parametric source of current, to the output of which connected to the counter-parallel thyristor sets assembled on the bridge scheme. The control of thyristors in the current converter is carried out taking into account the characteristic features of the parametric source, to avoid overvoltage on its reactive elements, analyzed algorithmic and modulating functions of the system borne temporary diagrams.

scholarly journals QUALITY OF ‘TAHITI’ ACID LIME FERTILIZED WITH NITROGEN AND POTASSIUM IN THE SEMIARID REGION OF MINAS GERAIS

2017 ◽  
Vol 39 (2) ◽  
Author(s):  
ARIANE CASTRICINI ◽  
JOSÉ TADEU ALVES DA SILVA ◽  
INÊZ PEREIRA DA SILVA ◽  
MARIA GERALDA VILELA RODRIGUES
Keyword(s):  
Ascorbic Acid ◽  
Titratable Acidity ◽  
Soluble Solids ◽  
Semiarid Region ◽  
Skin Thickness ◽  
Juice Quality ◽  
Acid Lime ◽  
Technological Index ◽  
External Characteristics ◽  
Juice Content

ABSTRACT This study aimed to evaluate external characteristics and juice obtained from ‘Tahiti’ acid lime produced under nitrogen and potassium fertilization. This study had a completely randomized design with three replicates of four fruits of the two central plants, 4 x 5 factorial and four N doses (0, 25, 50 and 100 Kg ha-1 year- 1) and five K2O doses (0, 25, 50, 100 and 200 Kg ha-1 year- 1), totaling 20 treatments. In the postharvest period, external characteristics (size, color and skin thickness, firmness and fresh mass) and juice (content, percentage, soluble solids, technological index, pH, titratable acidity, ratio and ascorbic acid) of fruits were evaluated. Size, skin color, soluble solids content and pH of ‘Tahiti’ acid lime juice were not affected by N and K2O fertilization. Skin thickness, juice percentage and technological index increased with the N and K2O doses applied to the soil. Juice content and fruit firmness decreased with application of K2O doses. Titratable acidity and ascorbic acid content increased with K2O doses. The different nitrogen and potassium doses influenced more the juice quality than the external characteristics of ‘Tahiti’ acid lime in the postharvest period.

scholarly journals Semantics of pre-war names of lviv villas

2020 ◽  
Vol 69 ◽  
pp. 53-63
Author(s):  
Kseniya Borodin ◽  
Keyword(s):  
Key Words ◽  
Religious Affiliation ◽  
Well Being ◽  
Present Stage ◽  
Dwelling House ◽  
The Times ◽  
The City ◽  
Coats Of Arms ◽  
House Building ◽  
External Characteristics

Background: The names of houses in Lviv, including villas, are still an unexplored niche in Lviv studies. The issue of semantics of pre-war names of Lviv villas is important at the present stage of the development of the onomastic research. It gives the clue of a good house name to modern naming and house-building companies. Purpose: The author put forward the task to acquaint readers with the Lviv’s named villas (ХІХ–the beginning of ХХ century), to describe the specification of naming features and name functions in diachronic cut and to define semantic groups of villa`s names. They appeared in the times when in naming there was no real practical need and became a manifestation of home essence, a mediator in communication between the owner, the host and a passerby, a potential guest. The name of the house emphasized its individuality, charm, created an emotional personal component of the city text. It was associated with its owners and gave an idea of the level of well-being, education, national composition and religious affiliation of the inhabitants. Results: Lviv`s villas were named mostly in Polish by its owners, architects or citizens. Their purposes were to nominate, distinguish (address function), inform, separate from the others, express oneself as an author, as well as to advertise. The nominative field of Lviv`s house names is represented by women’s names and their shorten forms, words with positive associations, sometimes with several meanings, family coats of arms, external characteristics and location of the house. Key words: name semantic, nominating field, dwelling house, villa, L’viv.

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