EVALUATION OF POTENTIAL ELUANTS FOR NON-ACID ELUTION OF CESIUM FROM SPHERICAL RESORCINOL-FORMALDEHYDE RESIN (open access)

EVALUATION OF POTENTIAL ELUANTS FOR NON-ACID ELUTION OF CESIUM FROM SPHERICAL RESORCINOL-FORMALDEHYDE RESIN

Ion Exchange column loading and elution of cesium from spherical resorcinol-formaldehyde resin have been conducted for two potential non-acid eluants -(NH{sub 4}){sub 2}CO{sub 3} and CH{sub 3}COONH{sub 4}. The results revealed encouraging cesium elution performance. 100% elution was achieved in at most 22 hours ({approx}28 bed volumes) of elution. Elution performance was fairly high at 6 hours ({approx}8 bed volumes) of elution for some of the eluants and also practically comparable to the benchmark acid eluant (HNO{sub 3}). Hence, it is quite possible 100% percent elution will be closer to the 6th hour than the 22nd hour. Elution is generally enhanced by increasing the concentration and pH of the eluants, and combining the eluants.
Date: October 23, 2011
Creator: Adu-Wusu, K.; Nash, C. & Pennebaker, F.
System: The UNT Digital Library
Atomic-level cotrol of the thermoelectric properties in polytypoid nanowires (open access)

Atomic-level cotrol of the thermoelectric properties in polytypoid nanowires

Thermoelectric materials have generated interest as a means of increasing the efficiency of power generation through the scavenging of waste heat. Materials containing nanometer-sized structural and compositional features can exhibit enhanced thermoelectric performance due to the decoupling of certain electrical and thermal properties, but the extent to which these features can be controlled is often limited. Here we report a simple synthesis of M{sub 2}O{sub 3}(ZnO){sub n} (M = In, Ga, Fe) nanowires with controllable polytypoid structures, where the nanostructured features are tuned by adjusting the amount of metal precursor. After the introduction of nanometer-scale features (individual atomic layers and alloying), thermal and electrical measurements on single In{sub 2-x}Ga{sub x}O3(ZnO){sub n} nanowires reveal a simultaneous improvement in all contributing factors to the thermoelectric figure of merit, indicating successful modification of the nanowire transport properties.
Date: October 23, 2010
Creator: Andrews, Sean C.; Fardy, Melissa A.; Moore, Michael C.; Aloni, Shaoul; Zhang, Minjuan; Radmilovic, Velimir et al.
System: The UNT Digital Library
CO{sub 2} Sequestration Potential of Charqueadas Coal Field in Brazil (open access)

CO{sub 2} Sequestration Potential of Charqueadas Coal Field in Brazil

The I2B coal seam in the Charqueadas coal field has been evaluated as a target for enhanced coal bed methane production and CO{sub 2} sequestration. The samples were low rank coals (high volatile bituminous and sub-bituminous) obtained from the I2B seam as �3� cores. Such properties as sorption capacity, internal structure of the samples, porosity and permeability were of primary interest in this characterization study.
Date: October 23, 2012
Creator: Romanov, V.
System: The UNT Digital Library
Compact Cdznte-Based Gamma Camera for Prostate Cancer Imaging (open access)

Compact Cdznte-Based Gamma Camera for Prostate Cancer Imaging

In this paper, we discuss the design of a compact gamma camera for high-resolution prostate cancer imaging using Cadmium Zinc Telluride (CdZnTe or CZT) radiation detectors. Prostate cancer is a common disease in men. Nowadays, a blood test measuring the level of prostate specific antigen (PSA) is widely used for screening for the disease in males over 50, followed by (ultrasound) imaging-guided biopsy. However, PSA tests have a high false-positive rate and ultrasound-guided biopsy has a high likelihood of missing small cancerous tissues. Commercial methods of nuclear medical imaging, e.g. PET and SPECT, can functionally image the organs, and potentially find cancer tissues at early stages, but their applications in diagnosing prostate cancer has been limited by the smallness of the prostate gland and the long working distance between the organ and the detectors comprising these imaging systems. CZT is a semiconductor material with wide band-gap and relatively high electron mobility, and thus can operate at room temperature without additional cooling. CZT detectors are photon-electron direct-conversion devices, thus offering high energy-resolution in detecting gamma rays, enabling energy-resolved imaging, and reducing the background of Compton-scattering events. In addition, CZT material has high stopping power for gamma rays; for medical imaging, a …
Date: October 23, 2011
Creator: Cui, Y.; Lall, T.; Tsui, B.; Yu, J.; Mahler, G.; Bolotnikov, A. et al.
System: The UNT Digital Library
Grain Sorting in Cometary Dust from the Outer Solar Nebula (open access)

Grain Sorting in Cometary Dust from the Outer Solar Nebula

None
Date: October 23, 2012
Creator: Wozniakiewicz, P J; Bradley, J P; Ishii, H A; Brownlee, D E; Kearsley, A T; Burchell, M J et al.
System: The UNT Digital Library
Development of an instrument for non-destructive identification of Unexploded Ordnance using tagged neutrons - a proof of concept study (open access)

Development of an instrument for non-destructive identification of Unexploded Ordnance using tagged neutrons - a proof of concept study

Range clearance operations at munitions testing grounds must discriminate Unexploded Ordnance (UXO) from clutter items and distinguish UXO filled with High Explosives (HE) from those with inert fillers. Non-destructive technologies are thus necessary for the cost-effective disposal of UXO during remediation of such sites. The only technique showing promise so far for the non-destructive elemental characterization of UXO fillers utilizes neutron interactions with the material to detect carbon (C), nitrogen (N) and oxygen (O) which have unique ratios in HE. However, several unresolved issues hinder the wide application of this potentially very suitable technique. The most important one is that neutrons interact with all surrounding matter in addition to the interrogated material, leading to a very high gamma-ray background in the detector. Systems requiring bulky shielding and having poor signal-to-noise ratios (SNRs) for measuring elements are unsuitable for field deployment. The inadequacies of conventional neutron interrogation methods are overcome by using the tagged-neutron approach, and the availability of compact sealed neutron generators exploiting this technique offers field deployment of non-intrusive measurement systems for detecting threat materials, like explosives and drugs. By accelerating deuterium ions into a tritium target, the subsequent fusion reaction generates nearly back-to-back emissions of neutrons and alpha …
Date: October 23, 2011
Creator: Mitra, S. & Dioszegi, I.
System: The UNT Digital Library
Game design for visually-impaired individuals: Creativity and innovation theories and sensory substitution devices influence on virtual and physical navigation skills (open access)

Game design for visually-impaired individuals: Creativity and innovation theories and sensory substitution devices influence on virtual and physical navigation skills

This article examines the design elements of three virtual reality games for functionality and transferability to orientation and mobility education for visually impaired individuals.
Date: October 23, 2018
Creator: Baker, Rose M.; Ramos, Karina & Turner, John
System: The UNT Digital Library
One thousand plant transcriptomes and the phylogenomics of green plants (open access)

One thousand plant transcriptomes and the phylogenomics of green plants

Article describes the results of the One Thousand Plant Transcriptomes Initiative's efforts to sequence the vegetative transcriptomes of 1,124 species that span the diversity of plants in a broad sense (Archaeplastida), including green plants (Viridiplantae), glaucophytes (Glaucophyta) and red algae (Rhodophyta).
Date: October 23, 2019
Creator: One Thousand Plant Transcriptomes Initiative
System: The UNT Digital Library
Space-charge-based electrostatic plasma confinement involving relaxed plasma species (open access)

Space-charge-based electrostatic plasma confinement involving relaxed plasma species

In this article, a numerical study is reported on the equilibrium properties of a surface-emitted or edge-confined non-drifting plasma. A self-consistent finite-differences evaluation of the electrostatic potential is carried out for a non-neutral plasma that follows a Boltzmann density distribution.
Date: October 23, 2012
Creator: Pacheco, J. L.; Ordonez, Carlos A. & Weathers, Duncan L.
System: The UNT Digital Library
Determination of molar refractions and Abraham descriptors for tris(acetylacetonato)chromium(iii), tris(acetylacetonato)iron(iii) and tris(acetylacetonato)cobalt(iii) (open access)

Determination of molar refractions and Abraham descriptors for tris(acetylacetonato)chromium(iii), tris(acetylacetonato)iron(iii) and tris(acetylacetonato)cobalt(iii)

Article describes study in which researchers determined molar refractions of tris(acetylacetonato)chromium(III), tris(acetylacetonato)iron(III) and tris(acetylacetonato)cobalt(III).
Date: October 23, 2017
Creator: Abraham, M. H. (Michael H.); Acree, William E. (William Eugene); Fucaloro, Anthony F. & Zanella, Andrew W.
System: The UNT Digital Library
Evaluating player task engagement and arousal using electroencephalography (open access)

Evaluating player task engagement and arousal using electroencephalography

This paper from the 6th International Conference on Applied Human Factors and Ergonomics and the Affiliated Conference, AHFE 2015 conference proceedings coordinate task engagement data with arousal-valence data for application to expressive transformations to video game play in real time by tuning different performance parameters in an Engagement-Arousal rule system.
Date: October 23, 2015
Creator: McMahan, Timothy; Parberry, Ian & Parsons, Thomas D.
System: The UNT Digital Library
Variations in Park Facility Valuations across Neighborhoods (open access)

Variations in Park Facility Valuations across Neighborhoods

This article assesses the hedonic valuation of different types of park facilities.
Date: October 23, 2014
Creator: Leonard, Tammy; Zhang, Lei & Hoehner, Christine M.
System: The UNT Digital Library
Development of Cdznte Radiation Detectors (open access)

Development of Cdznte Radiation Detectors

Cadmium Zinc Telluride (CdZnTe or CZT) is a very attractive material for room-temperature semiconductor detectors because of its wide band-gap and high atomic number. Despite these advantages, CZT still presents some material limitations and poor hole mobility. In the past decade most of the developing CZT detectors focused on designing different electrode configurations, mainly to minimize the deleterious effect due to the poor hole mobility. A few different electrode geometries were designed and fabricated, such as pixelated anodes and Frisch-grid detectors developed at Brookhaven National Lab (BNL). However, crystal defects in CZT materials still limit the yield of detector-grade crystals, and, in general, dominate the detector's performance. In the past few years, our group's research extended to characterizing the CZT materials at the micro-scale, and to correlating crystal defects with the detector's performance. We built a set of unique tools for this purpose, including infrared (IR) transmission microscopy, X-ray micro-scale mapping using synchrotron light source, X-ray transmission- and reflection-topography, current deep level transient spectroscopy (I-DLTS), and photoluminescence measurements. Our most recent work on CZT detectors was directed towards detailing various crystal defects, studying the internal electrical field, and delineating the effects of thermal annealing on improving the material properties. In …
Date: October 23, 2011
Creator: Bolotnikov, A.; Camarda, G.; Hossain, A.; Kim, K. H.; Yang, G.; Gul, R. et al.
System: The UNT Digital Library