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The Uiuc Virtual Spectrometer: A Java-Based Collaborative Learning Environment, Michael C. Dorneich, Patricia M. Jones Oct 2001

The Uiuc Virtual Spectrometer: A Java-Based Collaborative Learning Environment, Michael C. Dorneich, Patricia M. Jones

Michael C. Dorneich

The development of the UIUC Virtual Spectrometer (UIUC-VS), an interactive, Java-based simulation and tutoring system, is discussed. The apprenticeship model oflearning is utilized to create a learning environment for the study of a one-dimensional proton nuclear magnetic resonance (NMR) experiment, with the goal of linking theoretical knowledge with practical operational experience. Active, exploratory, apprentice-style learning is supported via modes of operation within the system. Students can flexibly choose to "observe the expert" perform and explain operational steps, or "act as an apprentice" and carry out the steps autonomously. Students can switch between modes at their discretion, giving them control of ...


In-Vivo 3d Motion Estimation Of The Shoulder Joint Utilizing Magnetic Resonance Imaging During A Simulated Push Task, D. M. Magnusson, Antonie J. Van Den Bogert, J. L. Ronsky May 2001

In-Vivo 3d Motion Estimation Of The Shoulder Joint Utilizing Magnetic Resonance Imaging During A Simulated Push Task, D. M. Magnusson, Antonie J. Van Den Bogert, J. L. Ronsky

Antonie J. van den Bogert

No abstract provided.


Melting And Resolidification Of A Substrate Caused By Molten Microdroplet Impact, Daniel Attinger, D. Poulikakos Mar 2001

Melting And Resolidification Of A Substrate Caused By Molten Microdroplet Impact, Daniel Attinger, D. Poulikakos

Daniel Attinger

This paper describes the main features and results of a numerical investigation of molten microdroplet impact and solidification on a colder flat substrate of the same material that melts due to the energy input from the impacting molten material. The numerical model is based on the axisymmetric Lagrangian Finite-Element formulation of the Navier–Stokes, energy and material transport equations. The model accounts for a host of complex thermofluidic phenomena, exemplified by surface tension effects and heat transfer with solidification in a severely deforming domain. The dependence of the molten volume on time is determined and discussed. The influence of the ...


Statistical Modeling Of Sprays Using The Droplet Distribution Function, Shankar Subramaniam Mar 2001

Statistical Modeling Of Sprays Using The Droplet Distribution Function, Shankar Subramaniam

Shankar Subramaniam

The theoretical foundations of a statistical spray modeling approach based on the droplet distribution function ~ddf!, which was originally proposed by Williams @Phys. Fluids 1, 541 ~1958!#, are established. The equation governing the ddf evolution is derived using an alternative approach. The unclosed terms in the ddf evolution equation are precisely defined, and the regime of applicability of current models is discussed. The theory of point processes is used to rigorously establish the existence of a disintegration of the ddf in terms of a spray intensity, which is the density of expected number of spray droplets in physical space, and ...


Rough Wall Modification Of Two-Layer K-E, Paul A. Durbin, G. Medic, J.-M. Seo, J. K. Eaton, S. Song Mar 2001

Rough Wall Modification Of Two-Layer K-E, Paul A. Durbin, G. Medic, J.-M. Seo, J. K. Eaton, S. Song

Paul A. Durbin

A formulation is developed to apply the two-layer k-ε model to rough surfaces. The approach involves modifying the ℓv formula and the boundary condition on k. A hydrodynamic roughness length is introduced and related to the geometrical roughness through a calibration procedure. An experiment has been conducted to test the model. It provides data on flow over a ramp with and without surface roughness.


Anodisation Of Copper In Thiourea-And Formamidine Disulphide-Containing Acid Solution.: Part I. Identification Of Products And Reaction Pathway Jan 2001

Anodisation Of Copper In Thiourea-And Formamidine Disulphide-Containing Acid Solution.: Part I. Identification Of Products And Reaction Pathway

A.S. Md Abdul Haseeb

The anodic behaviour of copper in aqueous 0.5 M sulphuric acid containing different amounts of dissolved thiourea or formamidine disulphide was investigated at 298 K, combining data from electrochemical polarisation, chemical analysis, UV–vis spectroscopy, XPS and EDAX analysis, and structural information on copper–thiourea complexes. The main reactions depend on the applied potential and initial thiourea concentration. In the potential range −0.30≤E≤0.075 V (versus SCE), the electro-oxidation of thiourea to formamidine disulphide, the formation of Cu(I)–thiourea soluble complexes, and Cu(I)–thiourea complex polymer-like films, are the most relevant processes. The formation ...


Mössbauer Investigation On Electrodeposited Fe-C And Fe-Ni-C Alloys Jan 2001

Mössbauer Investigation On Electrodeposited Fe-C And Fe-Ni-C Alloys

A.S. Md Abdul Haseeb

Hard Fe-C based alloys, Fe-0.96 mass% C and Fe-15.4 mass% C having a microhardness of 810 and 750 HV, respectively, are electrodeposited from sulfate-based baths at 50°C. The Mössbauer spectra consist of high intensity sextet due to ferromagnetic Fe. The linewidth of the sextet is larger for alloys than for the pure Fe, indicating an increased effective field at different Fe sites in the alloys. Absence of any low intensity sextet, which is attributable to the Fe atoms close to the C atoms at the octahedral c-axis position, suggests that the electrodeposited alloys are in an advanced ...


Thermal Decomposition Study Of Electrodeposited Fe-C And Fe-Ni-C Alloys By Differential Scanning Calorimetry Jan 2001

Thermal Decomposition Study Of Electrodeposited Fe-C And Fe-Ni-C Alloys By Differential Scanning Calorimetry

A.S. Md Abdul Haseeb

Fe-0.96mass%C and Fe-15.4mass%Ni-0.70mass%C alloys with hardness of 810 and 750 HV respectively have been electrodeposited at 50°C from sulphate based baths containing a small amount of citric acid and L-ascorbic acid. Differential scanning calorimetry of the electrodeposited samples has been carried out in the temperature range of 293-725 K in argon atmosphere. Electrodeposited pure Fe is also investigated for comparison purposes. The DSC curves of both alloys contain two exothermic peaks: at about 411 K and 646 K for the Fe-C alloy, and 388 K and 639 K for the Fe-Ni-C alloy. These ...


Static Friction And Surface Roughness Studies Of Surface Micromachined Electrostatic Micromotors Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan Jan 2001

Static Friction And Surface Roughness Studies Of Surface Micromachined Electrostatic Micromotors Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan

Sriram Sundararajan

A technique to measure the static friction forces (stiction) encountered in surface micromachined micromotors using a commercial atomic force microscope (AFM)/friction force microscope has been developed and is described. An AFM tip is pushed against a rotor arm of the micromotor so as to generate lateral deflection (torsion) of the tip, which is measured by the AFM. The maximum value of the lateral deflection obtained prior to rotor movement (rotation) is a measure of the static friction force of the micromotors. This technique was employed to study the effect of humidity and rest time on the static friction force ...


Development Of A Continuous Microscratch Technique In An Atomic Force Microscope And Its Application To Study Scratch Resistance Of Ultrathin Hard Amorphous Carbon Coatings, Sriram Sundararajan, Bharat Bhushan Jan 2001

Development Of A Continuous Microscratch Technique In An Atomic Force Microscope And Its Application To Study Scratch Resistance Of Ultrathin Hard Amorphous Carbon Coatings, Sriram Sundararajan, Bharat Bhushan

Sriram Sundararajan

A method to measure friction during scratching at linearly increasing loads in a commercial atomic force/friction force microscope (AFM/FFM) has been developed. The normal load was increased in small increments over the required range for the scratch using a software module while the friction signal was measured via a breakout box and data acquisition computer. Topography images of the scratch were obtained in situ with the AFM in tapping mode with minimal loss of damage event information. This technique was employed to study the scratch resistance of hard amorphous carbon coatings of thicknesses ranging from 20 nm down ...