scholarly journals Problems of natural lighting for deepened buildings and underground premises under screen effect of high-rise construction

2018 ◽  
Vol 33 ◽  
pp. 02017
Author(s):  
Kira Larionova ◽  
Sergey Stetsky
Keyword(s):  
Theoretical Calculations ◽  
Research Work ◽  
Experimental Studies ◽  
Screen Effect ◽  
Lighting System ◽  
Method Of Calculation ◽  
Natural Lighting ◽  
High Rise ◽  
Urban Territories ◽  
New Formula

The main rationale and objective of the submitted research work is to create a quality lighting environment in the premises of deepened buildings and below-ground structures under screen effect of high-rise construction (high-rise buildings). It is noted, that in modern megapolises, a deficiency of vacant urban territories leads to the increased density of urban development with increased amount of high-rise construction and tendency to increase efficiency in the use of underground space. The natural lighting of premises in underground buildings and structures is the most efficient way, but it can be implemented only under use of roof lighting system in the form of roof monitors or skylights. In this case the levels of indoor natural lighting will be affected with serious screening effect of high-rise buildings in surrounding development. Such an situation is not regulated, or even considered by the contemporary building Codes and Regulations on natural lighting of interiors. The authors offered a new formula for a daylight factor calculation with roof lighting system in the described cases. The results of theoretical calculations and experimental studies showed very similar values. This proved the truth of the offered formula and elaborated method of calculation on the basis of an offered hypothesis. It prooves, that it is possible to use some factor and guide points in the daylight factors design under system of side natural lighting in the same design for a system of roof lighting.

Luminous Environment and the Perceived Environment

2019 ◽  
pp. 15-21
Author(s):  
Banu Manav
Keyword(s):  
Experimental Studies ◽  
Light Output ◽  
Lighting Design ◽  
Lighting System ◽  
Main Concept ◽  
Healthy Environment ◽  
Perceived Environment ◽  
Efficiency Cost ◽  
Lighting Systems ◽  
User Friendly

In lighting design, the main concept is to achieve a healthy environment, which addresses energy efficiency, cost, maintenance, and quality. User-friendly lighting systems shall be adopted to architecture and interior architecture. User control over the lighting system is important, by dimming or increasing light output, by changing the colour of the light sets the inner atmosphere and affects user mood. Standards and codes on lighting shall also be evaluated by means of these topics. The paper aims to analyse how the luminous environment is affective on the perceived environment. Hence, a series of experimental studies and recent research will be evaluated in regard to understanding and designing luminous environment.

Daylight in Underground Spaces

2018 ◽  
pp. 156-161
Author(s):  
Alexei K. Solovyov
Keyword(s):  
Light Guide ◽  
Heat Losses ◽  
Internal Environment ◽  
Method Of Calculation ◽  
Natural Lighting ◽  
Different Depths ◽  
The Common ◽  
Different Diameters

Underground spaces in town centres present a big attraction for investors. However, they put special requirements to the internal environment. Those requirements can be fulfilled by means of daylighting. Examples of lighting of underground spaces are discussed. It is shown that the common systems of natural lighting are not always possible to use and cause big heat losses. Hollow light guide pipes allow avoid the shortcomings of common daylight systems. Method of calculation of daylight factors from hollow light guide pipes is shown. The results of calculation of daylight factors under the light guide pipes of different diameters in the different depths are presented.

Theoretical and experimental studies of palladium-catalyzed site-selective C(sp3)−H bond functionalization enabled by transient ligands

2017 ◽  
Author(s):  
Haibo Ge ◽  
Lei Pan ◽  
Piaoping Tang ◽  
Ke Yang ◽  
Mian Wang ◽  
...  
Keyword(s):  
Bond Activation ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Bond Functionalization ◽  
Aliphatic Ketones ◽  
Site Selectivity ◽  
Mechanistic Investigation ◽  
Palladium Catalyzed ◽  
Metal Catalyzed ◽  
Site Selective

Transition metal-catalyzed selective C–H bond functionalization enabled by transient ligands has become an extremely attractive topic due to its economical and greener characteristics. However, catalytic pathways of this reaction process on unactivated sp<sup>3</sup> carbons of reactants have not been well studied yet. Herein, detailed mechanistic investigation on Pd-catalyzed C(sp<sup>3</sup>)–H bond activation with amino acids as transient ligands has been systematically conducted. The theoretical calculations showed that higher angle distortion of C(sp2)-H bond over C(sp3)-H bond and stronger nucleophilicity of benzylic anion over its aromatic counterpart, leading to higher reactivity of corresponding C(sp<sup>3</sup>)–H bonds; the angle strain of the directing rings of key intermediates determines the site-selectivity of aliphatic ketone substrates; replacement of glycine with β-alanine as the transient ligand can decrease the angle tension of the directing rings. Synthetic experiments have confirmed that β-alanine is indeed a more efficient transient ligand for arylation of β-secondary carbons of linear aliphatic ketones than its glycine counterpart.<br><br>

CALCULATION OSCILLATIONS OF VARIOUS ELEMENTS OF THE ELASTIC SYSTEM OF THE CENTER-FREE GRINDING MACHINE SASL 5AD

2020 ◽  
pp. 160-165
Author(s):  
Джугурян Т.Г. ◽  
Марчук В.І. ◽  
Марчук І. В.
Keyword(s):  
Horizontal Plane ◽  
Natural Frequencies ◽  
Elastic System ◽  
Experimental Studies ◽  
Piezoelectric Sensors ◽  
Forced Oscillations ◽  
Method Of Calculation ◽  
Vibration Resistance ◽  
Grinding Machine ◽  
Experimental Researches

During the design of operations of centerless intermittent grinding of surfaces there is a need to identify the natural frequencies of oscillations of the elements of the technological system of grinding. The method of calculation of rigidity, vibration resistance and forced oscillations of the elements of the circular grinding machine is offered in the article. Carrying out of experimental researches of rigidity of elastic system of the SASL 5AD grinding machine. We conducted preliminary experimental studies to measure the oscillations of various elements of the elastic system of the SASL 5AD grinding machine in the horizontal plane by piezoelectric sensors during grinding with continuous and discontinuous circles with different geometric parameters.

Zn diffusion and reflow behaviour of Sn-9Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga solders on a Ni/Cu substrate under IR reflow

2014 ◽  
Vol 26 (2) ◽  
pp. 87-95 ◽  
Author(s):  
J. Mittal ◽  
K.L. Lin
Keyword(s):  
Theoretical Calculations ◽  
Research Work ◽  
Content Type ◽  
Diffusion Behavior ◽  
Zn Diffusion ◽  
Cu Substrate ◽  
Practical Applications ◽  
Substrate Interface ◽  
Solder Balls ◽  
Practical Implications

Purpose – This paper aims to compare the reflow and Zn diffusion behaviors in Sn-Zn and Sn-8.5Zn-0.5Ag-0.01Al-0.1Ga (5E) solders during soldering on a Ni/Cu substrate under infrared (IR) reflow. The study proposes a model on the effect of various elements particularly Zn diffusion behavior in the solders on the formation of intermetallic compounds (IMCs). Design/methodology/approach – The melting activities of two solders near their melting points on copper substrates are visualized in an IR reflow furnace. Reflowed solder joints were analyzed using scanning electron microscope and energy dispersive X-ray spectroscopy. Findings – Reflow behaviors of the solders are similar. During melting, solder balls are first merged into each other and then reflow on the substrate from top to bottom. Both solders show a reduced amount of Zn in the solder. Theoretical calculations demonstrate a higher Zn diffusion in the 5E solder; however, the amount of Zn actually observed at the solder/substrate interface is lower than Sn-9Zn solder due to the formation of ZnAg3 in the solder. A thinner IMC layer is formed at the interface in the 5E solder than the Sn-Zn solder. Research limitations/implications – The present work compares the 5E solder only with Sn-Zn solder. Additional research work may be required to compare 5E solder with other solders like Sn-Ag, SnAgCu, etc. to further establish its practical applications. Practical implications – The study ascertains the advantages of 5E solder over Sn-Zn solder for all practical applications. Originality/value – The significance of this paper is the understanding of the relation between reflow behavior of solders and reactivity of different elements in the solder alloys and substrate to form various IMCs and their influence on the formation of IMC layer at solder/substrate interface. Emphasis is provided for the diffusion behavior of Zn during reflow and respective reaction mechanisms.

Film thickness in elastohydrodynamically lubricated slender elliptic contacts: Part I – numerical studies of central film thickness

2021 ◽  
pp. 135065012110477
Author(s):  
Marius Wolf ◽  
Sergey Solovyev ◽  
Fatemi Arshia
Keyword(s):  
Film Thickness ◽  
State Of The Art ◽  
Experimental Studies ◽  
Elastohydrodynamic Lubrication ◽  
Large Parameter ◽  
Numerical Studies ◽  
Minimum Film Thickness ◽  
Subsequent Publication ◽  
New Formula ◽  
Increasing Load

In this paper, analytical equations for the central film thickness in slender elliptic contacts are investigated. A comparison of state-of-the-art formulas with simulation results of a multilevel elastohydrodynamic lubrication solver is conducted and shows considerable deviation. Therefore, a new film thickness formula for slender elliptic contacts with variable ellipticity is derived. It incorporates asymptotic solutions, which results in validity over a large parameter domain. It captures the behaviour of increasing film thickness with increasing load for specific very slender contacts. The new formula proves to be significantly more accurate than current equations. Experimental studies and discussions on minimum film thickness will be presented in a subsequent publication.

scholarly journals GIS use in solving water supplying and water environmental problems of Urban Territories

2018 ◽  
Vol 170 ◽  
pp. 04008
Author(s):  
Nadezhda Kurepina ◽  
Irina Rybkina
Keyword(s):  
Water Management ◽  
Research Work ◽  
Environmental Problems ◽  
Geoinformation Systems ◽  
Step Procedure ◽  
Wide Range ◽  
Urban Territories ◽  
Cartographic Modeling ◽  
Academy Of Sciences ◽  
Regional Water

Geoinformation systems (GIS) are actively used in modern scientific research, including the field of Urban Territories’ management. The lack of a universal methodology for their application requires an individual approach in the study of water management and water and environmental problems in the region. The purpose of this article is to demonstrate concrete examples of GIS successful use in solving some water supplying problems. One of the leading research methods is geoinformation-cartographic modeling, which has a wide range of possibilities and contributes to the effective solution of water-related and water-ecological regional problems. The developed algorithm for GIS using in solving regional water, a step-by-step procedure organizes for carrying out research work, the presented structure of the thematic database facilitates the systematizatin of thematic data large volume with the base a GIS project is created, where information is integrated, calculations, and a cartographic model is created that visualizes the regional water management and water-e logical situation. The research examples carried out in the Institute of Hydrometeorology of the Russian Academy of Sciences (Siberian Branch) on regional water management and water ecological problems by means of GIS and using the method of geoinformation-cartographic modeling considered in this paper prove the effectiveness and their use expediency.

Research of stamping of unequal channel bars. Part 5. Methods for calculating the extrusion of channels. 2. Extrusion of non-strengthening material

2021 ◽  
pp. 46-52
Author(s):  
A.L. Vorontsov
Keyword(s):  
Plane Strain ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
High Accuracy ◽  
Experimental Results ◽  
Die Forging

The results of experimental studies on the extrusion of channels from non-strengthening material are presented. Comparison of theoretical calculations with experimental results showed the high accuracy of the derived formulas. Keywords: die forging, extrusion, punch, matrix, misalignment, plane strain. [email protected]

scholarly journals Platinum–copper single atom alloy catalysts with high performance towards glycerol hydrogenolysis

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Xi Zhang ◽  
Guoqing Cui ◽  
Haisong Feng ◽  
Lifang Chen ◽  
Hui Wang ◽  
...  
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Reaction Pathway ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Value Added ◽  
Catalytic Performance ◽  
Single Atom ◽  
Glycerol Hydrogenolysis ◽  
Single Atom Alloy

AbstractSelective hydrogenolysis of biomass-derived glycerol to propanediol is an important reaction to produce high value-added chemicals but remains a big challenge. Herein we report a PtCu single atom alloy (SAA) catalyst with single Pt atom dispersed on Cu nanoclusters, which exhibits dramatically boosted catalytic performance (yield: 98.8%) towards glycerol hydrogenolysis to 1,2-propanediol. Remarkably, the turnover frequency reaches up to 2.6 × 103 molglycerol·molPtCu–SAA−1·h−1, which is to our knowledge the largest value among reported heterogeneous metal catalysts. Both in situ experimental studies and theoretical calculations verify interface sites of PtCu–SAA serve as intrinsic active sites, in which the single Pt atom facilitates the breakage of central C–H bond whilst the terminal C–O bond undergoes dissociation adsorption on adjacent Cu atom. This interfacial synergistic catalysis based on PtCu–SAA changes the reaction pathway with a decreased activation energy, which can be extended to other noble metal alloy systems.

scholarly journals Numerical simulation of the stress-strain state of complex-reinforced elements

2019 ◽  
Vol 13 (2) ◽  
pp. 110-115
Author(s):  
Olena Krantovska ◽  
Mykola Petrov ◽  
Liubov Ksonshkevych ◽  
Matija Orešković ◽  
Sergii Synii ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Strain State ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Theoretical Studies ◽  
Stress Strain ◽  
Narrow Strip ◽  
Stress Strain State ◽  
Graphical Environment ◽  
Experimental And Theoretical Studies

The article describes a developed technique of a numerical simulation of the stress-strain state of complex-reinforced elements, which allows you to create models of double-span continuous. The performed experimental and theoretical studies allowed us to carry out the testing of the developed design model and to justify the reliability of the proposed numerical simulation methodology. The results of the experimental studies were compared with those of the theoretical studies. The theoretical calculus algorithm was developed by using the finite element method. Theoretical calculations were performed by using the mathematical-graphical environment software system LIRA-SOFT and the mathematical and computer program MATLAB. On the basis of the experimental research, the iso-fields of displacements and stresses in the materials of an eccentrically compressed beam with a small bend of the slab were constructed, which collapse behind the inclined narrow strip of concrete and displacements and stresses in the materials of the eccentrically stretched beam, which is destroyed due to the yield of the upper mounting armature.

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