Design of cold-formed compression web members with periodically varying section properties

2007 ◽  
Vol 34 (2) ◽  
pp. 253-265
Author(s):  
Serge Parent ◽  
Joseph J Pote ◽  
Kenneth W Neale
Keyword(s):  
Cross Sections ◽  
Design Method ◽  
Design Procedure ◽  
Effective Length ◽  
Cross Sectional ◽  
The North ◽  
Stub Column ◽  
Flexural Torsional Buckling ◽  
Open Face

In this paper, a design procedure for cold-formed channels periodically closed on their open face and utilized as joist web members is detailed. The design method for periodically closed sections is based on the representation of the cross-sectional properties using Fourier series introduced in Timoshenko quotients for the determination of the buckling loads about each of the three member axes. Once those loads are computed, they are used in the current framework of the North American Specification for the design of cold-formed structures with appropriate effective length coefficients. The proposed design methodology is compared with test results obtained from 36 stub column samples and 21 full-scale joist specimens, also presented in this paper.Key words: cold-formed struts, periodically varying cross sections, steel joists, flexural–torsional buckling, effective length coefficients.

Gender determination of caucasoid hair using image analysis

1993 ◽  
Vol 51 ◽  
pp. 216-217
Author(s):  
T.B. Ball ◽  
W.M. Hess
Keyword(s):  
Image Analysis ◽  
Cross Sections ◽  
Scalp Hair ◽  
The Body ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Hair Samples ◽  
Length Width ◽  
Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

Determination of Fiber Cross-Sectional Circularity From Measurements Made in a Longitudinal View

1979 ◽  
Vol 101 (1) ◽  
pp. 59-64 ◽  
Author(s):  
R. L. Barker ◽  
D. W. Lyons
Keyword(s):  
Cross Sections ◽  
Analytical Procedure ◽  
Cross Sectional ◽  
Longitudinal View ◽  
Made In

A procedure is described for obtaining information concerning the circularity of fiber cross-sections from measurements made in a longitudinal view of the fibers. A method is developed for viewing and measuring the projected diameter of fibers viewed longitudinally, and an analytical procedure is described for analyzing these measurements to determine the flatness or roundness of the fiber cross-sections. Experimentation conducted to test the reliability of these procedures is discussed as these methods are used to measure numerous different samples of fibers of known and varied cross-sectional shapes and sizes.

Buckling Behaviour of Stainless Steel Square Hollow Sections

2016 ◽  
Vol 853 ◽  
pp. 301-305
Author(s):  
Shameem Ahmed ◽  
Mahmud Ashraf ◽  
Mohammad Anwar-Us-Saadat
Keyword(s):  
Stainless Steel ◽  
Strain Hardening ◽  
Cross Sections ◽  
Design Method ◽  
Numerical Models ◽  
Slenderness Ratio ◽  
Design Guidelines ◽  
Material Nonlinearity ◽  
Cross Sectional ◽  
Steel Design

Structural stainless steel design guidelines should appropriately recognise its characteristic beneficial properties such as material nonlinearity and significant strain hardening. The Continuous Strength Method (CSM) exploits those through a strain based approach for both stocky and slender cross-sections. In this paper, a new design method is proposed that combines the CSM with Perry type buckling curves. Numerical models were developed to investigate effects of various parameters on column strength and to develop full column curves. It was observed that material nonlinearity significantly influence column strengths, and hence, different column curves were developed for a total of 20 material property combinations by calibrating imperfection factor and limiting slenderness ratio for each set. Proposed method includes the strain hardening benefits for stocky section, and abolished the necessity of calculating effective cross-sectional properties for slender sections. Performance of the proposed technique is compared against those obtained by the Eurocode EN1993-1-4.

Displacement-Based Lateral Stiffness Design for Multi-Storey Structures Subject to Earthquake Motions

2012 ◽  
Vol 166-169 ◽  
pp. 2337-2340
Author(s):  
Feng Wang ◽  
Hong Nan Li ◽  
Ting Hua Yi
Keyword(s):  
Subjective Experience ◽  
Design Method ◽  
Design Procedure ◽  
Lateral Stiffness ◽  
Stiffness Design ◽  
Target Period ◽  
Displacement Based ◽  
Seismic Design Method ◽  
Adjustment Parameter

The determination of structural stiffness for the currently seismic design method depends on subjective experience of designers which is not rational and economical. A method that uses displacements as the basis for the stiffness design procedure is then presented: (1)By means of preliminary design, the initial elastic structure are obtained and the 1th mode shape, period etc are then calculated by modal analyses; (2) The target period and lateral equivalent stiffness of structure are determined according to target displacement used in seismic code; (3)The two periods for initial designed structure and target structure are compared and the lateral stiffness is adjusted to make the displacement responses of the structural weak members meet the limited displacements by adjustment parameter. An example is implemented for demonstrating the process and verifying the accuracy of the procedure.

scholarly journals Determination of Pesticide Residues in Food Premises Using QuECHERS Method in Bench-Sheko Zone, Southwest Ethiopia

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Besufekad Mekonnen ◽  
Jafer Siraj ◽  
Samuel Negash
Keyword(s):  
Pesticide Residues ◽  
Human Life ◽  
Cereal Crops ◽  
Cross Sectional ◽  
Southwest Ethiopia ◽  
Governmental Organizations ◽  
The North ◽  
Human Health Effects ◽  
Local Farmers

Pesticides are risk factors in human life causing chronic human health effects. They are commonly used across the globe to enhance human endeavors. In Ethiopia, pesticides are widely used by local farmers and governmental organizations for pest control purpose. Pesticide residues in food items have been a concern to the consumers and environment they live in. Therefore, this study was aimed at determining the amount of organochlorine and organophosphate pesticide residues in cereal crops in Bench-Sheko Zone, Ethiopia. A cross-sectional laboratory-based study design was employed to determine the amount of pesticide residues. The samples were extracted using a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction and clean up method. Finally, the extracted samples were injected into gas chromatography tandem mass spectrometer and the types and concentrations of pesticide residues were analyzed. The highest concentration of endosulfan sulfate (0.076 mgkg-1) was detected in rice, followed by dimethoate (0.068 mgkg-1) and p,p ′ -DDE (0.087 mgkg-1) in sorghum and common millet, respectively, in the samples obtained from the Gurafarda site.The highest concentration of p,p ′ -DDT (0.133 mgkg-1) was detected in common millet, followed by aldrin (0.082 mgkg-1) and dimethoate (0.077 mgkg-1) in sorghum and common millet, respectively, in the samples obtained from the North Bench site. In addition, aldrin detected in rice, sorghum, and common millet obtained from the three sites was a residue of above the maximum residual limits set by Codex Alimentarius regulations and European Union. The finding shows that an indication of the widespread use of pesticides in cereal crops.

scholarly journals AGE DETERMINATION AND PALAEOGEOGRAPHIC RECONSTRUCTION OF DIAPONDIA ISLANDS IN NW GREECE, BASED ON CALCAREOUS NANNOFOSSILS

2017 ◽  
Vol 43 (2) ◽  
pp. 675
Author(s):  
G. Makrodimitras ◽  
K. Stoykova ◽  
I. Vakalas ◽  
A. Zelilidis
Keyword(s):  
Cross Sections ◽  
Age Determination ◽  
Calcareous Nannofossils ◽  
Late Oligocene ◽  
Submarine Fans ◽  
The North ◽  
Western Area ◽  
North Western ◽  
Of Greece

Diapondia islands - Ereikoussa, Othonoi and Mathraki – extended in the north-western area of Greece, are part of the external Ionian zone of the Hellenides. The exposed sedimentary succession of the three islands consists of up to 74m thick submarine fans, interpreted as inner fan deposits. The determination of the sediment ages is based on the study of calcareous nannofossils, which came from almost 63 samples covering geological cross sections across the coast line of the three islands. The recorded nannofossil associations are assigned to the biozones of Martini’s (1971) standard scheme. According to the age determination clastic sedimentation in the studied area started during the Late Oligocene and finished during the Early Miocene time. Moreover, the age determination and in accordance with the previous results, indicate that also the Ionian thrust activity started during Late Oligocene.

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.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Preparation And elemental analysis of ancient fibers

1987 ◽  
Vol 45 ◽  
pp. 410-411
Author(s):  
Allen Angel ◽  
Kathryn A. Jakes
Keyword(s):  
Cross Sections ◽  
Physical Structure ◽  
Energy Dispersive ◽  
Archaeological Sites ◽  
X Ray ◽  
Long Term Storage ◽  
Backscattered Electron ◽  
Electron Imaging

Fabrics recovered from archaeological sites often are so badly degraded that fiber identification based on physical morphology is difficult. Although diagenetic changes may be viewed as destructive to factors necessary for the discernment of fiber information, changes occurring during any stage of a fiber's lifetime leave a record within the fiber's chemical and physical structure. These alterations may offer valuable clues to understanding the conditions of the fiber's growth, fiber preparation and fabric processing technology and conditions of burial or long term storage (1).Energy dispersive spectrometry has been reported to be suitable for determination of mordant treatment on historic fibers (2,3) and has been used to characterize metal wrapping of combination yarns (4,5). In this study, a technique is developed which provides fractured cross sections of fibers for x-ray analysis and elemental mapping. In addition, backscattered electron imaging (BSI) and energy dispersive x-ray microanalysis (EDS) are utilized to correlate elements to their distribution in fibers.

Profil Penyakit Malaria Di Rumah Sakit Islam Siti Rahmah Padang Tahun 2018

2020 ◽  
Vol 2 (2) ◽  
pp. 08-15
Author(s):  
Rahma Triyana ◽  
Salmi Salmi
Keyword(s):  
Observational Study ◽  
Frequency Distribution ◽  
Cross Section ◽  
Laboratory Tests ◽  
Age Group ◽  
Normal Range ◽  
Cross Sectional ◽  
West Sumatra ◽  
Severity Of The Disease

Malaria is one of the health problems in Indonesia, especially West Sumatra. Determination of the description of Malaria disease in an area is needed to determine the spread and severity of the disease. This study aims to determine the frequency distribution according to age, sex and place of residence, description of the types of Plasmodium causes of Malaria and hematological features in Malaria patients at Siti Rahmah Padang Hospital in 2018. This type of research is a descriptive observational study with an approach or design cross section (cross sectional). The frequency distribution of Malaria sufferers in Siti Rahmah Padang Hospital in 2018 according to the highest age was in the age group 21-30 years as many as 28 cases (36.8%), the highest sex among men was 46 (60.5%) and the highest number of residences was found in Koto Tangah sub-district there were 31 cases (40.8%). The type of Plasmodium found in Malaria cases in Siti Rahmah Padang Hospital in 2018 was P. vivax (73 cases (96.05%)) and P. falciparum (3 cases (3.95%)). The results of laboratory tests on Hb, hematocrit, platelet and leukocyte levels in Malaria positive patients in Siti Rahmah Padang Hospital in 2018 were in the normal range.

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