ABSTRACT--Strain distributions to failure, tensile and compressive strain-concentration factors, ... more ABSTRACT--Strain distributions to failure, tensile and compressive strain-concentration factors, and strength-reduc-tion factors were determined for glass-, boron-, and graphite-epoxy plates with holes loaded in tension. Strain gages, photoelastic coatings and moir6 ...
Electrospray ionisation mass spectrometry (ESI-MS) has been used for the determination and quanti... more Electrospray ionisation mass spectrometry (ESI-MS) has been used for the determination and quantitation of a broad range of 24 antibiotics, from groups including aminoglycosides, beta-lactams, tetracyclines, antifungals and glycopeptides. Spectra have been acquired for all 24 antibiotics derived from pure samples dissolved in acetonitrile/water, along with samples extracted from complex fermentation liquor. Quantitation was carried out by the detection of the protonated molecules, using time-scheduled single-ion monitoring (SIM). ESI-MS was used to detect and quantify to 5-microM levels. A one-step extraction of antibiotics with an organic solvent (methanol) was used for this rapid and simple procedure. Specificity is not matched by other methods and antibiotic analogues (e.g. the five forms of erythromycin) can be determined within minutes.
ABSTRACT--Strain distributions to failure, tensile and compressive strain-concentration factors, ... more ABSTRACT--Strain distributions to failure, tensile and compressive strain-concentration factors, and strength-reduc-tion factors were determined for glass-, boron-, and graphite-epoxy plates with holes loaded in tension. Strain gages, photoelastic coatings and moir6 ...
ABSTRACT----Cubic-spline and discrete-quadratic polynomial techniques are presented for reliably ... more ABSTRACT----Cubic-spline and discrete-quadratic polynomial techniques are presented for reliably computing up to third-order derivatives of experimental information. The concept is demonstrated by stress analyzing from measured displace-ments a transversely loaded plate and a ...
ABSTRACT We demonstrate the ability to determine stress intensity factors in orthotropic material... more ABSTRACT We demonstrate the ability to determine stress intensity factors in orthotropic materials directly from measured temperatures away from the crack and using far-field expressions for the stresses. This is advantageous, recognizing that recorded thermoelastic data can be very unreliable near the tip of a crack. In addition to singular terms that govern in the immediate vicinity of the crack tip, the present series expressions for the stresses contain higher-order finite terms. Little measured input information is needed and data acquisition positions can be selected largely at the user's discretion.
The isochromatic and isopachic fringes are obtained holographically in the neighborhood of a cent... more The isochromatic and isopachic fringes are obtained holographically in the neighborhood of a central crack in a tensile, orthotropic glass-composite plate. The general inability to separate the principal stresses or strains from such information alone under anisotropic conditions is discussed, as are the results relative to fracture-mechanics implications.
Using strain-induced orthotropic material concepts, a new numerical constitutive model is demonst... more Using strain-induced orthotropic material concepts, a new numerical constitutive model is demonstrated by predicting the ultimate capacity of a unique simple test specimen and two cylindrical shell structures. Only the uniaxial compressive strength of the concrete and the yield stress of the reinforcing steel are needed as input to predict both constitutive behavior and structural strength. The approach is simple,
ABSTRACT--Strain distributions to failure, tensile and compressive strain-concentration factors, ... more ABSTRACT--Strain distributions to failure, tensile and compressive strain-concentration factors, and strength-reduc-tion factors were determined for glass-, boron-, and graphite-epoxy plates with holes loaded in tension. Strain gages, photoelastic coatings and moir6 ...
Electrospray ionisation mass spectrometry (ESI-MS) has been used for the determination and quanti... more Electrospray ionisation mass spectrometry (ESI-MS) has been used for the determination and quantitation of a broad range of 24 antibiotics, from groups including aminoglycosides, beta-lactams, tetracyclines, antifungals and glycopeptides. Spectra have been acquired for all 24 antibiotics derived from pure samples dissolved in acetonitrile/water, along with samples extracted from complex fermentation liquor. Quantitation was carried out by the detection of the protonated molecules, using time-scheduled single-ion monitoring (SIM). ESI-MS was used to detect and quantify to 5-microM levels. A one-step extraction of antibiotics with an organic solvent (methanol) was used for this rapid and simple procedure. Specificity is not matched by other methods and antibiotic analogues (e.g. the five forms of erythromycin) can be determined within minutes.
ABSTRACT--Strain distributions to failure, tensile and compressive strain-concentration factors, ... more ABSTRACT--Strain distributions to failure, tensile and compressive strain-concentration factors, and strength-reduc-tion factors were determined for glass-, boron-, and graphite-epoxy plates with holes loaded in tension. Strain gages, photoelastic coatings and moir6 ...
ABSTRACT----Cubic-spline and discrete-quadratic polynomial techniques are presented for reliably ... more ABSTRACT----Cubic-spline and discrete-quadratic polynomial techniques are presented for reliably computing up to third-order derivatives of experimental information. The concept is demonstrated by stress analyzing from measured displace-ments a transversely loaded plate and a ...
ABSTRACT We demonstrate the ability to determine stress intensity factors in orthotropic material... more ABSTRACT We demonstrate the ability to determine stress intensity factors in orthotropic materials directly from measured temperatures away from the crack and using far-field expressions for the stresses. This is advantageous, recognizing that recorded thermoelastic data can be very unreliable near the tip of a crack. In addition to singular terms that govern in the immediate vicinity of the crack tip, the present series expressions for the stresses contain higher-order finite terms. Little measured input information is needed and data acquisition positions can be selected largely at the user's discretion.
The isochromatic and isopachic fringes are obtained holographically in the neighborhood of a cent... more The isochromatic and isopachic fringes are obtained holographically in the neighborhood of a central crack in a tensile, orthotropic glass-composite plate. The general inability to separate the principal stresses or strains from such information alone under anisotropic conditions is discussed, as are the results relative to fracture-mechanics implications.
Using strain-induced orthotropic material concepts, a new numerical constitutive model is demonst... more Using strain-induced orthotropic material concepts, a new numerical constitutive model is demonstrated by predicting the ultimate capacity of a unique simple test specimen and two cylindrical shell structures. Only the uniaxial compressive strength of the concrete and the yield stress of the reinforcing steel are needed as input to predict both constitutive behavior and structural strength. The approach is simple,
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Papers by R. Rowlands