New in Old: Simplified Equations for Linear-elastic Symmetric Arches and Insights on Their Behavior

2020 ◽  
Vol 61 (3) ◽  
pp. 227-240
Author(s):  
Branko Glisic
Keyword(s):  
Cross Sections ◽  
Normal Force ◽  
Approximate Equation ◽  
Structural Behavior ◽  
Structural Systems ◽  
Linear Elastic ◽  
Wide Range ◽  
Different Types ◽  
Internal Forces

Closed-form equations for determination of reactions and internal forces of linear-elastic symmetric arches with constant cross-sections are derived. The derivation of the equations was initially made for segmental, threehinged, two-hinged, and hingeless arches. Not all derived equations are simple, but still not excessively complex to apply, and they reveal several new insights into the structural behavior of arches. The first is an extremely simple approximate equation for horizontal reactions of a hingeless arch under self-weight, which could be also applied with excellent accuracy to catenary and parabolic arches, and with a desirable level of accuracy to two- and three-hinged arches with a relatively wide range of geometries. The second insight is an approximately linear relationship between reactions and between internal forces of arches with different structural systems, which helps understand the global structural behavior of arches in a new way and enables inference of some other insights presented in the paper. The third insight reflects the relationships between normal force distribution and its eccentricity in different types of arches. Finally, the fourth insight regards the comparison of behavior of arches under the self-weight with those loaded with uniformly distributed load along their span.

scholarly journals Basic Concepts of Structural Design for Architecture Students

2021 ◽  
Author(s):  
Anahita Khodadadi ◽  
Keyword(s):  
Material Properties ◽  
Structural Design ◽  
Structural Systems ◽  
Structural Elements ◽  
Math Problem Solving ◽  
Vector Addition ◽  
Rules Of Thumb ◽  
Different Types ◽  
Internal Forces ◽  
Basic Concepts

This book aims to narrate fundamental concepts of structural design to architecture students such that they have minimum involvement with math problem-solving. Within this book, students learn about different types of loads, forces and vector addition, the concept of equilibrium, internal forces, geometrical and material properties of structural elements, and rules of thumb for estimating the proportion of some structural systems such as catenary cables and arches, trusses, and frame structures.

Molar absorptivities of human hemoglobin in the visible spectral range

1983 ◽  
Vol 54 (5) ◽  
pp. 1287-1291 ◽  
Author(s):  
W. G. Zijlstra ◽  
A. Buursma ◽  
A. Zwart
Keyword(s):  
Human Blood ◽  
Hemoglobin Concentration ◽  
Visible Spectral Range ◽  
Human Hemoglobin ◽  
Spectrophotometric Methods ◽  
Total Hemoglobin ◽  
Wide Range ◽  
Different Types ◽  
Total Hemoglobin Concentration

In a recent paper, Burkhard and Barnikol (J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 52: 124–130, 1982) claimed that the absorption spectra of human (oxy-)hemoglobin are dependent on the total hemoglobin concentration (CHb) and it is suggested that this might also be the case with cyanmethemoglobin (HiCN). Such relationships would invalidate the widely used spectrophotometric methods for the determination of total hemoglobin and the fractions of various hemoglobin derivatives in human blood. Although Burkhard and Barnikol's findings are rather improbable considering earlier data, we measured the millimolar absorptivities of oxyhemoglobin (epsilon HbO2) and cyanmethemoglobin (epsilon HiCN) at various wavelengths over a wide range of concentrations (CHb approximately equal to 0.004–10 mmol x 1(-1)), using two different types of spectrophotometers. epsilon HbO2 and epsilon HiCN proved to be independent of CHb. Moreover the values obtained confirmed those in the earlier literature, whereas those of Burkhard and Barnikol are some 30% higher. Consequently there is no reason to doubt the validity of the generally accepted millimolar absorptivities of human hemoglobin.

Analysis of the Influence of Dynamic Properties of Structures on Seismic Response According to Montenegrin and European Regulations

2014 ◽  
Vol 633-634 ◽  
pp. 1069-1076 ◽  
Author(s):  
Ivan Mrdak ◽  
Marina Rakočević ◽  
Ljiljana Žugić ◽  
Rustam Usmanov ◽  
Vera Murgul ◽  
...  
Keyword(s):  
Seismic Design ◽  
Dynamic Characteristics ◽  
Nonlinear Deformation ◽  
Dynamic Properties ◽  
Structural Systems ◽  
Strong Earthquakes ◽  
Linear Elastic ◽  
European Regulations ◽  
Two Phases

The motion of strong earthquakes causes nonlinear deformation and damages to the structure. For structural systems of buildings, domestic and European (EC8) regulation apply algorithm of seismic design based on reference linear-elastic methods that are carried out in two phases. Phase I includes determination of dynamic characteristics of structure, which are then used in phase II for calculation of seismic effects. In this study, parametric analysis of influence of dynamic characteristics of structure was done on multiple numerical examples, according to domestic and EC8 regulations and comparison of results.

Valence shell absolute photoabsorption oscillator strengths, constrained dipole oscillator strength distributions, and dipole properties for CH3NH2, (CH3)2NH, and (CH3)3N

1994 ◽  
Vol 72 (3) ◽  
pp. 529-546 ◽  
Author(s):  
Gordon R. Burton ◽  
Wing Fat Chan ◽  
Glyn Cooper ◽  
C.E. Brion ◽  
Ashok Kumar ◽  
...  
Keyword(s):  
Oscillator Strength ◽  
Cross Sections ◽  
Oscillator Strengths ◽  
Valence Shell ◽  
Reliable Determination ◽  
Sum Rule ◽  
Wide Range ◽  
Dipole Oscillator ◽  
Strength Distributions

Dipole (e,e) spectroscopy has been used to measure the absolute photoabsorption oscillator strengths (cross sections) for the valence shells of CH3NH2, (CH3)2NH, and (CH3)3N from the photoabsorption threshold to 250 eV at low resolution (∼1 eV fwhm) and to 31 eV at high resolution (0.048 eV fwhm). The observed peaks in the photoabsorption spectra of the methylamines have been assigned to transitions to Rydberg orbital upper states. Our measured photoabsorption data, augmented by mixture rule estimates for high photon energies, have been used in conjunction with Thomas–Reiche–Kuhn sum rule and molar refractivity constraints, to construct constrained dipole oscillator strength distributions for each of the methylamines. From these constrained dipole oscillator strength distributions a wide range of related dipole properties have been calculated for each of the methylamines, and in most cases the results so obtained represent the first (reliable) determination of these properties.

scholarly journals A Theoretical Assessment of the Formation of IT clusters in Kazakhstan

2016 ◽  
Vol 5 (3) ◽  
pp. 54-65
Author(s):  
Anel A Kireyeva
Keyword(s):  
Advanced Technology ◽  
Complex Objects ◽  
Conceptual Approach ◽  
Theoretical Approaches ◽  
Industrial Parks ◽  
Different Types ◽  
Internal Forces ◽  
Structured Approach ◽  
Theoretical Assessment

The aim of this research is to develop new theoretical approaches of the formation of IT clusters in order to strengthen of trend of the innovative industrialization and competitiveness of the country. Keeping with the previous literature, this study determines by the novelty of the problem, concerning the formation of IT clusters, which can become a driving force of transformation due to the interaction, improving efficiency and introducing advanced technology. In this research, we used conceptual approach employs the study of different conceptual views of scientists on a specific research object; structured approach involves determination of properties of a whole object by identifying the different relationships; system approach aims to develop research methods and design of complex objects – systems of different types. This study allows to conclude that IT-clusters will be most effective when they evolve naturally, originating under the action of internal forces of consolidation of  innovative, information and communications infrastructure (industrial parks, techno polis, research laboratories and business incubators, formation of soft infrastructure), that can help to find quick, innovative and creative ways to solve problems.

scholarly journals Analytical Method for Determination of Internal Forces of Mechanisms and Manipulators

Robotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 53 ◽  
Author(s):  
Muratulla Utenov ◽  
Tarek Sobh ◽  
Zhumadil Baigunchekov ◽  
Saltanat Zhilkibayeva ◽  
Sarosh Patel
Keyword(s):  
Cross Sections ◽  
Discrete Model ◽  
Discrete Models ◽  
Dynamic Loads ◽  
Dynamic Equations ◽  
Analytical Determination ◽  
Kinematic Characteristics ◽  
Internal Forces ◽  
Rigid Joints

This paper presents a theory for the analytical determination of internal forces in the links of planar linkage mechanisms and manipulators with statically determinate structures, considering the distributed dynamic loads. Linkage mechanisms and manipulators were divided into elements and joints. Discrete models were created for both the elements and the entire mechanism. The dynamic equations of equilibrium for the discrete model of the elements and the hinged and rigid joints, under the action of longitudinal and transverse distributed dynamic trapezoidal loads, were derived. In the dynamic equations of the equilibrium of the discrete model of the elements and joints, the connections between the components of the force vector in the calculated cross-sections and the geometric, physical, and kinematic characteristics of the element were established for its plane-parallel motion. According to the developed technique, programs were created in the Maple system, and animations of the motion of the mechanisms were produced. The links were constructed with the intensity of transverse- and longitudinal-distributed dynamic loads, bending moments, and shearing and normal forces, depending on the kinematic characteristics of the links.

XIII.—The Appearance in Cross-section of the Hairs of some Carnivores and Rodents

1944 ◽  
Vol 62 (1) ◽  
pp. 99-104 ◽  
Author(s):  
J. L. Stoves
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Chemical Reactivity ◽  
Chemical Properties ◽  
Morphological Differentiation ◽  
Taxonomic Significance ◽  
Structural Variations ◽  
Wide Range ◽  
Different Types ◽  
Whole Mounts

Examination of mammalian pelts reveals the presence of two types of hair—long, glossy fibres known as “guard”- or “top-hair,” and shorter, softer, more curly fibres termed ”ground”- or “under-wool.” Guard-hairs are of two kinds: primary fibres classified by Toldt (1910) as “Leithaare,” and shorter, less robust secondary fibres which Toldt described as “Grannenhaare.” The under-wool is analogous to Toldt's “Wohlhaare.” More recently Toldt (1935) has described the appearance of the various fibre types occurring in hair from a wide range of mammals, and gives an extensive bibliography on hair from many orders of mammalia, including the two at present under consideration. Glaister (1931) made a photomicrographic survey of whole mounts and transverse sections of fibres from a large number of mammals. This work, however, suffers from the disadvantage that the photomicrographs were taken at low magnifications. When photographed at magnifications of the order × 500, transverse sections of fibres readily demonstrate the distribution and structure of cuticle, cortex and medulla. Such information is valuable as a means of studying structural variations in hair from different types of mammals, and often possesses considerable taxonomic significance and practical value—Dearborn (1939) reports the use of cross-sections of mammalian guard-hairs as a help to identifying small hairs found in the stomachs and excreta of predators, while the importance of fibre histology in forensic science has been reviewed by Smith and Glaister (1939). Furthermore, microchemical tests carried out on wool fibres (Bekker and King, 1931) and on transverse sections of kolinsky and hare fibres (Stoves, 1943 a) have shown that cuticle, cortex, and medulla exhibit different chemical properties, so that morphological differentiation is accompanied by variation in chemical reactivity.

Diffusion and flow of gases and vapours through micropores I. Slip flow and molecular streaming

1950 ◽  
Vol 203 (1072) ◽  
pp. 55-74 ◽  
Keyword(s):  
Transition Region ◽  
Cross Sections ◽  
Slip Flow ◽  
Gradual Change ◽  
Considerable Uncertainty ◽  
Fine Powders ◽  
True Value ◽  
Pore Texture ◽  
Wide Range

It has been shown that the slight minimum found by Knudsen in the plot of G against p for circular capillaries is very much exaggerated for non-circular cross-sections. Since the pore-system in a porous medium must correspond to non-circular sections, a similar minimum might be expected. Such a possibility would give rise to considerable uncertainty in applying gas permeabilities to the determination of specific surfaces of very fine powders, when flow takes place mainly by molecular streaming. The minimum should appear when d e = λ (transition region). By using a number of powders of different particle size and four different gases, a very wide range of values of d e /λ on both sides of unity has been covered. It has been established clearly that, while the plot of G against p sometimes undergoes a small and very gradual change of gradient in the transition region, no sign of a minimum has been detected. For all practical purposes, it is sufficient to assume that G against p is linear for all values of p . For a powder of Pyrex glass microspheres, the value of δ/k´ = 0·46, which agrees in magnitude with theoretical expectations. For different plugs, and also for the same plug, when G against p is curved, δ/k´ has different values, but the total range of variation is not large. The foregoing conclusions are not dependent on porosity or pore texture. The pore texture of fine powders at high porosities is so non-uniform that the surface calculated from permeability is 50% or less of its true value, but the transition from slip flow to streaming is unaffected and values of δ/k´ are normal.

Analysis of STEM micrographs of thick objects

1978 ◽  
Vol 36 (2) ◽  
pp. 106-107
Author(s):  
S. Golladay
Keyword(s):  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Mass Distribution ◽  
Cross Sections ◽  
Phase Contrast ◽  
Image Point ◽  
Contrast Effects ◽  
Total Cross Sections ◽  
Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

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