Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Missouri University of Science and Technology

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 14281 - 14310 of 21750

Full-Text Articles in Engineering

Web Crippling Behaviour Of Cold-Formed Unlipped Channels, Ben Young, Gregory J. Hancock Oct 1998

Web Crippling Behaviour Of Cold-Formed Unlipped Channels, Ben Young, Gregory J. Hancock

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

An experimental investigation of cold-formed unlipped channels subject to web crippling is described. The tests were carried out under four loading conditions according to the AISI Specification, namely End-One-Flange (EOF), Interior-One-Flange (IOF), End-Two-Flange (ETF), and Interior-Two-Flange (ITF) loading. The concentrated load or reaction forces were applied by means of bearing plates which acted across the full flange widths of the channels. The web crippling test results are compared with the American Iron and Steel Institute (AISI 1996) Specification and the Australian/New Zealand Standard (AS/NZS 4600-1996) for cold-formed steel structures. The design web crippling strength predictions given by the specifications have …

Go to article

Web Crippling Of Cold Formed Steel Members, K. Prabakaran, R. M. Schuster Oct 1998

Web Crippling Of Cold Formed Steel Members, K. Prabakaran, R. M. Schuster

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

A new design expression for web crippling of cold formed steel members has been developed. An extensive statistical analysis was performed using published test data from Canada, the United States, Sweden and France to develop new expressions for the web crippling strength of cold formed steel members under four different loading cases, i.e. (1) end one-flange loading (EOF), (2) interior one-flange loading (lOF), (3) end two-flange loading (ETF) and (4) interior two-flange loading (lTF). I-sections made of two channels connected back-to-back, Z-sections, channels and multiple web sections (decks) were considered. Comparisons were made with the web crippling expressions presented in …

Go to article

Columns Under Loads Of Varying Eccentricity, J. Rhodes Oct 1998

Columns Under Loads Of Varying Eccentricity, J. Rhodes

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

A series of tests on small lipped channel section columns is reported in this paper. The columns were loaded with varying degrees of eccentricity. The eccentricity of loading was produced by offsetting the loading line from the neutral axis of the section, and the offset could be set to a different degree at each end of the column. By this means the effect of moment variation along the column could be examined experimentally and the results compared with the predictions of different design codes for this type of loading. The predictions of the 1986 AISI Specification, the British Standard and …

Go to article

Shift Of The Effective Centroid Of Channel Columns, Ben Young, Kim J. R. Rasmussen Oct 1998

Shift Of The Effective Centroid Of Channel Columns, Ben Young, Kim J. R. Rasmussen

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

In the design of pin-ended channel columns, it is necessary to account for the shift of the effective centroid caused by local buckling. The current American Iron and Steel Institute (AISI 1996) Specification and the Australian/New Zealand Standard (AS/NZS 4600-1996) for cold-formed steel structures calculate the shift by use of effective widths. However, the ability of the effective width rules to accurately predict this shift has not been experimentally assessed. In this paper, recent tests on fixed-ended channel columns are used to obtain values of the shift of the effective centroid, including its variation with the applied load. In the …

Go to article

Tests Of Cold-Formed Channel Columns, Ben Young, Kim J. R. Rasmussen Oct 1998

Tests Of Cold-Formed Channel Columns, Ben Young, Kim J. R. Rasmussen

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The paper presents a series of tests on cold-formed plain and lipped channel columns, compressed between fixed and pinned ends. While it is well-known that local buckling of pin-ended channel columns induces overall bending, this phenomenon does not occur in fixed-ended channel columns which remain straight after local buckling and only bend when overall buckling occurs. These fundamentally different effects of local buckling on the behaviour of pin-ended and fixed-ended channel sections lead to inconsistencies in traditional design approaches, which account for full or partial rotational end restraint solely by using effective lengths. A series of tests was performed on …

Go to article

A European Design Code For Pallet Racking, M. H. R. Godley, J. Michael Davies Oct 1998

A European Design Code For Pallet Racking, M. H. R. Godley, J. Michael Davies

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The work leading to a European design code for pallet racking started almost 25 years ago. Many difficulties were encountered in the early days of this work. Notable were the absence of a consistent safety philosophy between the various countries of Europe and the existence of procedures with which the manufacturers were comfortable but which were potentially unsafe. There were also difficulties in defining acceptable standard. test procedures. The emergence of Eurocode 3, especially Part 1.3 dealing with cold formed sections, provided a new impetus to the work because here was a European code which provided the required basis for …

Go to article

Neuron Scattering Studies Of The Magnetic Fluctuations In Yba2cu3o7−Δ, Herbert A. Mook, Pengcheng Dai, Rodney Dale Hunt, Fatih Dogan Oct 1998

Neuron Scattering Studies Of The Magnetic Fluctuations In Yba2cu3o7−Δ, Herbert A. Mook, Pengcheng Dai, Rodney Dale Hunt, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Neutron scattering measurements were made on the spin fluctuations in YBa2Cu3O7−δ for different oxygen doping levels. Incommensurability is clearly observed for oxygen concentrations of 6.6 and 6.7 and is suggested for the 6.93. Measurements of the resonance for the O6.6 concentration show that it exists in a broadened and less intense form at temperatures much higher than Tc.

Go to article

Incorporating Vertical Discontinuities In Power-Bus Modeling Using A Mixed-Potential Integral Equation And Circuit Extraction Formulation, Jun Fan, Hao Shi, James L. Drewniak, Todd H. Hubing, Richard E. Dubroff, Thomas Van Doren Oct 1998

Incorporating Vertical Discontinuities In Power-Bus Modeling Using A Mixed-Potential Integral Equation And Circuit Extraction Formulation, Jun Fan, Hao Shi, James L. Drewniak, Todd H. Hubing, Richard E. Dubroff, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Noise on the DC power-bus attributed to device switching is among the primary sources of EMI and signal integrity problems. A mixed-potential integral equation formulation with circuit extraction approach is used to model the planar multi-layer power-bus geometry, which can also include arbitrary shaped power regions on multiple layers. Incorporating vertical discontinuities, e.g., decoupling capacitor interconnects, is a critical aspect of the modeling, and must be done properly since they are included as a lumped element model and not a part of the MPIE formulation. Agreement with experimental results demonstrate the present approach.

Go to article

Optimum Control Of A Hybrid System For Seismic Excitations With State Observer Technique, Franklin Y. Cheng, Hongping Jiang Oct 1998

Optimum Control Of A Hybrid System For Seismic Excitations With State Observer Technique, Franklin Y. Cheng, Hongping Jiang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents a theoretical study of a hybrid seismic response control system comprising a passive fluid viscous damper and an active control system with a hydraulic actuator and acceleration sensors. The analytical model of this system is derived in the discrete time domain with actuator and clamper dynamics considered. Based on digital control theory, a state observer is established for optimal control strategies of the hybrid system. This study shows that the hybrid system gains the advantages of both active and passive control techniques currently in vogue; and that, with the state observer technique, a seismic response control system …

Go to article

Magma Traps And Driving Pressure: Consequences For Pluton Shape And Emplacement In An Extensional Regime, John Patrick Hogan, Jonathan D. Price, M. Charles Gilbert Sep 1998

Magma Traps And Driving Pressure: Consequences For Pluton Shape And Emplacement In An Extensional Regime, John Patrick Hogan, Jonathan D. Price, M. Charles Gilbert

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The level of emplacement and final form of felsic and mafic igneous rocks of the Wichita Mountains Igneous Province, southwestern Oklahoma, U.S.A. Are discussed in light of magma driving pressure, lithostatic load, and crustal magma traps. Deposition of voluminous A-type rhyolites upon an eroded gabbroic substrate formed a subhorizontal strength anisotropy that acted as a crustal magma trap for subsequent rising felsic and mafic magma. Intruded along this crustal magma trap are the A-type sheet granites (length/thickness 100:1) of the Wichita Granite Group, of which the Mount Scott Granite sheet is typical, and smaller plutons of biotite bearing Roosevelt Gabbro. …

Go to article

Shell Cracking In Investment Casting With Laser Stereolithography Patterns, W. L. Yao, Ming-Chuan Leu Aug 1998

Shell Cracking In Investment Casting With Laser Stereolithography Patterns, W. L. Yao, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents an investigation of ceramic shell cracking during the burnout process in investment casting with internally webbed laser stereolithography patterns. We hypothesize that shell cracking will occur when the rupture temperature of the ceramic shell is lower than both the glass transition temperature of the pattern material and the web· link buckling temperature. The hypothesis is validated by our experimental observations which confirm the numerical predictions from our finite element analysis. This provides a basis for design of the internal web geometry of a lithography pattern and evaluation of the burnout process with such a pattern. We show …

Go to article

Rapid Freezing Prototyping With Water, Wei Zhang, Ming-Chuan Leu, Zhiming Ji, Yongnian Yan Aug 1998

Rapid Freezing Prototyping With Water, Wei Zhang, Ming-Chuan Leu, Zhiming Ji, Yongnian Yan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Rapid Freezing Prototyping (RFP) with water is a novel solid freeform fabrication technique that can generate three-dimensional ice objects by depositing and rapidly freezing water layer by layer. The support where necessary is made of brine whose. freezing point is lower than. pure water. After building the part, the support can be removed by utilizing the melting temperature difference between brine and water. Preliminary experiments have shown that the ice patterns produced by this technique can be used for design visualization and silicone molding. This paper will present the concept and some experimental results of the RFP process as well …

Go to article

Ccfss Technical Bulletin August 1998, Wei-Wen Yu Center For Cold-Formed Steel Structures Aug 1998

Ccfss Technical Bulletin August 1998, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Technical Bulletins (1993 - 2020)

No abstract provided.

Go to article

Ccfss News August 1998, Wei-Wen Yu Center For Cold-Formed Steel Structures Aug 1998

Ccfss News August 1998, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

Go to article

Considerations For Magnetic-Field Coupling Resulting In Radiated Emi, David M. Hockanson, James L. Drewniak, Richard E. Dubroff, Todd H. Hubing, Thomas Van Doren Aug 1998

Considerations For Magnetic-Field Coupling Resulting In Radiated Emi, David M. Hockanson, James L. Drewniak, Richard E. Dubroff, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Parasitic inductance in printed circuit board geometries can worsen the EMI performance and signal integrity of high-speed digital designs. Partial-inductance theory is a powerful tool for analyzing inductance issues in signal integrity. However, partial inductances may not adequately model magnetic flux coupling to EMI antennas because the EMI antennas are typically open loops. Therefore, partial inductances may not always accurately predict radiated EMI from noise sources, unless used in a full-wave analysis such as PEEC. Partial inductances can be used, however, to estimate branch inductances, which can be used to predict EMI. This paper presents a method for decomposing loop …

Go to article

An Impact Of Layer Stack-Up On Emi, S. Radu, Theodore M. Zeeff, Joe Nuebel, James L. Drewniak, Todd H. Hubing, Thomas Van Doren Aug 1998

An Impact Of Layer Stack-Up On Emi, S. Radu, Theodore M. Zeeff, Joe Nuebel, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Investigation of a server shows the heatsink of the CPU module as a primary component of the EMI coupling path. In order to identify the specific noise source and coupling path to the heatsink, a series of experiments were defined to provide support for one source and eliminate others. Based on experiments with two different versions of the CPU module, a stack-up related design guideline is proposed: a ground layer should be the first entire plane (as opposed to Vcc) on the active component side of the board. If there are known IC sources that switch significant currents …

Go to article

Design Of Airflow Aperture Arrays In Shielding Enclosures, Min Li, S. Radu, J. Neubel, James L. Drewniak, Todd H. Hubing, Thomas Van Doren Aug 1998

Design Of Airflow Aperture Arrays In Shielding Enclosures, Min Li, S. Radu, J. Neubel, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

EMI through perforation patterns for airflow in shielding enclosures resulting from coupling of interior sources is investigated numerically with FDTD simulations and experimentally. The FDTD simulations are compared with measurements on perforation patterns. A simple empirical design approach for the relation between aperture size, the number of apertures and shielding effectiveness is extracted. A double perforation pattern structure is proposed for perforation pattern designs where a high percentage of open area is required. Frequencies where the enclosure will support cavity modes are of primary concern.

Go to article

Modeling Multilayered Pcb Power-Bus Designs Using An Mpie Based Circuit Extraction Technique, Hao Shi, Jun Fan, James L. Drewniak, Todd H. Hubing, Thomas Van Doren Aug 1998

Modeling Multilayered Pcb Power-Bus Designs Using An Mpie Based Circuit Extraction Technique, Hao Shi, Jun Fan, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

A circuit extraction tool (CEMPIE) has been developed based on the mixed-potential integral equation (MPIE) using a quasi-static approximation. A power-bus in a multi-layered PCB consisting of a pair of dedicated ground and power planes is studied using this tool. The distributed behavior of a power-bus is represented by a collection of passive circuit elements, which is valid up to several gigahertz. The decoupling performance of a power-bus due to its layer spacing and the dielectric constant is evaluated for simple test geometries. The impact of the relative distance between the noise source and the potential receiver is also studied. …

Go to article

Time History Extrapolation For Fdtd Modeling Of Shielding Enclosure Designs And Emi Antenna Geometries, Xiao Luo, Min Li, James L. Drewniak Aug 1998

Time History Extrapolation For Fdtd Modeling Of Shielding Enclosure Designs And Emi Antenna Geometries, Xiao Luo, Min Li, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

The GPOF (generalized pencil-of-function) method was used to extrapolate the time response from FDTD simulations of EMI problems by approximating the time history as a sum of complex exponentials. This method can significantly shorten the FDTD program execution time. However, various difficulties can arise from parameterization during data-processing. The GPOF is applied to, and studied for, two relevant EMI problems, enclosure design and EMI antenna modeling. The merits of GPOF in modeling shielding enclosures and EMI antennas is evaluated through several examples

Go to article

A Feasibility Study Of On-Line Excitation System Parameter Estimation, Eric Ludwig, K. Shah, Kelvin T. Erickson, Mariesa Crow Aug 1998

A Feasibility Study Of On-Line Excitation System Parameter Estimation, Eric Ludwig, K. Shah, Kelvin T. Erickson, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper details a feasibility study of estimating excitation system parameters during online operation using time-domain system identification. This study concentrates on identifying the appropriate exciter model, developing an input signal that would provide a proper level of perturbation such that the dynamics of the system can be captured, analyzing the effects of both systematic and random noise, developing algorithms to perform the parameter estimation, testing and validating the obtained system parameters. This study established a strong basis for estimating the system parameters during online operation.

Go to article

A Mentoring Guide For Female Faculty In Engineering, Susan L. Murray, Linda M. Manning, Catherine A. Riordan, Elizabeth Cummins, Philip B. Thompson Jul 1998

A Mentoring Guide For Female Faculty In Engineering, Susan L. Murray, Linda M. Manning, Catherine A. Riordan, Elizabeth Cummins, Philip B. Thompson

Engineering Management and Systems Engineering Faculty Research & Creative Works

One widely accepted method for increasing the chances of success of female engineering and science students and faculty alike is to provide access to female role models and mentors. In this article we offer to new female faculty, and to those who would mentor them, an annotated list of text and electronic resources that address most of the most important challenges facing new female faculty in science and engineering.

Go to article

A Technology Assessment Survey For Web Based Higher Education Programs, Earl A. Evans, Susan L. Murray Jul 1998

A Technology Assessment Survey For Web Based Higher Education Programs, Earl A. Evans, Susan L. Murray

Engineering Management and Systems Engineering Faculty Research & Creative Works

Advances in communications and computer technology, as well as in human-computer interfaces, have enabled concurrent advances in Web-based education. A number of case studies concerning applications of Web-based education for both distance learning and on-campus programs have been published. Primarily, these studies have focused on individual assessments of the web-based technologies. In contrast, this paper will provide a broad based assessment of applied web-based technology for higher education. This research was conducted via a survey completed by university and college faculty from numerous 4-year institutions. To gain an effective assessment, eleven categories of web-based course delivery tools, such as chatrooms …

Go to article

Effectiveness Of An On-Line Graduate Engineering Management Course: A Preliminary Study, Rosemarie Maffei Evans, Madison Daily, Susan L. Murray Jul 1998

Effectiveness Of An On-Line Graduate Engineering Management Course: A Preliminary Study, Rosemarie Maffei Evans, Madison Daily, Susan L. Murray

Engineering Management and Systems Engineering Faculty Research & Creative Works

In the summer of 1997, the University of Missouri-Rolla's (UMR) Engineering Management Department began offering its first completely Web-based course. This graduate level course, Advanced Production Management, was designed to utilize a combination of Web-based tools to create a conducive, yet non-traditional, learning environment for its students. The students in the course did not physically have to attend any lectures and only met for an initial and final class period. The remainder of the course was conducted exclusively via Web-based tools. Accordingly, the Engineering Management Department commenced a research effort to determine the effectiveness of this new learning environment. This …

Go to article

Fabrication Guidelines For Cold Bending (1998, Republished 2022), R. L. Brockenbrough & Associates, Inc. Jun 1998

Fabrication Guidelines For Cold Bending (1998, Republished 2022), R. L. Brockenbrough & Associates, Inc.

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

To avoid cracking plates during cold bending, it is necessary to adopt a suitable minimum inside bend radius, which typically varies with plate thickness and grade. However, because of the addition of new plate grades over the years, it was suspected that current limits may not have been developed on a consistent basis. Therefore, the American Iron and Steel Institute (AISI) initiated a program to develop rational limits in 1998. This study was made to review information obtained in recent tests and develop suggested fabrication guidelines.

Go to article

Mixed Electron Emission From Doped Pb(Zr,Ti)O₃ Ceramics: Microstructural Aspects, Weiming Zhang, Wayne Huebner Jun 1998

Mixed Electron Emission From Doped Pb(Zr,Ti)O₃ Ceramics: Microstructural Aspects, Weiming Zhang, Wayne Huebner

Materials Science and Engineering Faculty Research & Creative Works

A mixed type electron emission, i.e., simultaneous ferroelectric and plasma emission, was observed with a negative driving pulse applied to doped Pb(Zr,Ti)O3 ceramics in the absence of any external potential on the electron collector. During these emission studies, significant microstructural changes on the emission surface were observed, and corresponded to the different emission modes. Erosion craters at the edge of the electrode and small particles near these craters reflected the formation of a dense plasma there. Comparatively, cavities, i.e., grain pullouts, accumulated on the bare ferroelectric surface, the frequency of which depended upon its distance from the grid. This …

Go to article

Data-Driven Homologue Matching For Chromosome Identification, R. Joe Stanley, James M. Keller, Paul D. Gader, Charles William Caldwell Jun 1998

Data-Driven Homologue Matching For Chromosome Identification, R. Joe Stanley, James M. Keller, Paul D. Gader, Charles William Caldwell

Electrical and Computer Engineering Faculty Research & Creative Works

Karyotyping involves the visualization and classification of chromosomes into standard classes. In "normal" human metaphase spreads, chromosomes occur in homologous pairs for the autosomal classes 1-22, and X chromosome for females. Many existing approaches for performing automated human chromosome image analysis presuppose cell normalcy, containing 46 chromosomes within a metaphase spread with two chromosomes per class. This is an acceptable assumption for routine automated chromosome image analysis. However, many genetic abnormalities are directly linked to structural or numerical aberrations of chromosomes within the metaphase spread. Thus, two chromosomes per class cannot be assumed for anomaly analysis. This paper presents the …

Go to article

Mixed Electron Emission From Lead Zirconate-Titanate Ceramics, Weiming Zhang, Wayne Huebner, Stephen E. Sampayan, Mike L. Krogh Jun 1998

Mixed Electron Emission From Lead Zirconate-Titanate Ceramics, Weiming Zhang, Wayne Huebner, Stephen E. Sampayan, Mike L. Krogh

Materials Science and Engineering Faculty Research & Creative Works

Simultaneous ferroelectric and plasma emission from Pb(Zr,Ti)O3 was observed with only a negative driving pulse applied to the sample, and without an extraction potential on the electron collector. Plasma emission was a strong, inconsistent, and self-destructive process. In addition, a positive ion current was detected. Comparatively, ferroelectric emission was a relatively stable self-emission process, exhibiting no apparent delay time, and no positive ion current. The relationship between the switching and emission current of ferroelectric samples measured simultaneously cannot only be used to determine the existence of ferroelectric emission, but can also give direction to choosing suitable ferroelectric materials for …

Go to article

Cure-State Monitoring And Water-To-Cement Ratio Determination Of Fresh Portland Cement-Based Materials Using Near-Field Microwave Techniques, Karl Joseph Bois, Aaron D. Benally, Paul S. Nowak, R. Zoughi Jun 1998

Cure-State Monitoring And Water-To-Cement Ratio Determination Of Fresh Portland Cement-Based Materials Using Near-Field Microwave Techniques, Karl Joseph Bois, Aaron D. Benally, Paul S. Nowak, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Quick and nondestructive determination of curestate and water-to-cement (w/c) ratio in fresh Portland cementbased materials is an important issue in the construction industry since the compressive strength of these materials is significantly influenced by w/c ratio. This is especially true since current techniques are not reliable and require a priori testing of test specimens as calibration for subsequent on-site monitoring of a cast in-place structure. Recently, the sensing of Portland cementbased materials using microwave techniques has received much attention. Microwave nondestructive techniques have already shown the potential for determining w/c ratio, sand-to-cement (s/c) ratio and coarse aggregate-to-cement (ca/c) ratio in …

Go to article

Iron Phosphate Compositions For Containment Of Hazardous Metal Waste, D. E. Day May 1998

Iron Phosphate Compositions For Containment Of Hazardous Metal Waste, D. E. Day

Materials Science and Engineering Faculty Research & Creative Works

An improved iron phosphate waste form for the vitrification, containment and long-term disposition of hazardous metal waste such as radioactive nuclear waste is provided. The waste form comprises a rigid iron phosphate matrix resulting from the cooling of a melt formed by heating a batch mixture comprising the metal waste and a matrix-forming component. The waste form comprises from about 30 to about 70 weight percent P205 and from about 25 to about 50 weight percent iron oxide and has metals present in the metal waste chemically dissolved therein. The concentration of iron oxide in the waste form along with …

Go to article

Regarding The Correlation Of Nuclear Spin Relaxation And Electrical Conductivity Relaxation In Ionic Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow Apr 1998

Regarding The Correlation Of Nuclear Spin Relaxation And Electrical Conductivity Relaxation In Ionic Glasses, David L. Sidebottom, Peter F. Green, Richard K. Brow

Materials Science and Engineering Faculty Research & Creative Works

Much attention has been focused recently on the apparent differences between ion dynamics in ion-containing glasses as probed by electrical conductivity relaxation (ECR) and by nuclear spin relaxation (NSR) techniques. In both relaxation processes, a power law frequency dependence is observed. Based upon fluctuation-dissipation arguments, the power law exponents should be equivalent. However, experimentally, it appears that the conductivity exponent is generally smaller than the NSR exponent. While an explanation for this discrepancy based upon fundamental differences in the correlation functions probed by the two techniques has been proffered, we show how this discrepancy may simply arise from differing analyses …

Go to article

First Prev Next Last