Measurement of the Double-Beta Decay Half-life of {sup 136}Xe in KamLAND-Zen (open access)

Measurement of the Double-Beta Decay Half-life of {sup 136}Xe in KamLAND-Zen

We present results from the KamLAND-Zen double-beta decay experiment based on an exposure of 77.6 days with 129 kg of {sup 136}Xe. The measured two-neutrino double-beta decay half-life of {sup 136}Xe is T{sup 2{nu}}{sub 1/2} = 2:38 {+-}#6; 0:02(stat)#6;{+-}0.14(syst)#2;x10{sup 21} yr, consistent with a recent measurement by EXO-200. We also obtain a lower limit for the neutrinoless double-beta decay half-life, T{sup 0{nu}}{sub 1/2} > 5.7 x#2; 10{sup 24} yr at 90% C.L.
Date: January 23, 2012
Creator: Collaboration, KamLAND-Zen; Gando, A.; Gando, Y.; Hanakago, H.; Ikeda, H.; Inoue, K. et al.
System: The UNT Digital Library
Conformal growth of Mo/Si multilayers on grating substrates using collimated ion beam sputtering (open access)

Conformal growth of Mo/Si multilayers on grating substrates using collimated ion beam sputtering

Deposition of multilayers on saw-tooth substrates is a key step in the fabrication of multilayer blazed gratings (MBG) for extreme ultraviolet and soft x-rays. Growth of the multilayers can be perturbed by shadowing effects caused by the highly corrugated surface of the substrates, which results in distortion of the multilayer stack structure and degradation of performance of MBGs. To minimize the shadowing effects we used an ionbeam sputtering machine with a highly collimated atomic flux to deposit Mo/Si multilayers on saw-tooth substrates. The sputtering conditions were optimized by finding a balance between smoothening and roughening processes in order to minimize degradation of the groove profile in the course of deposition and at the same time to keep the interfaces of a multilayer stack smooth enough for high efficiency. An optimal value of energy of 200 eV for sputtering Kr{sup +} ions was found by deposition of test multilayers on flat substrates at a range of ion energies. Two saw-tooth substrates were deposited at energies of 200 eV and 700 eV for the sputtering ions. It was found that reduction of the ion energy improved the blazing performance of the MBG and resulted in a 40% gain in the diffraction efficiency …
Date: January 23, 2012
Creator: Gawlitza, Peter; Cambie, Rossana; Dhuey, Scott; Gullikson, Eric; Warwick, Tony; Braun, Stefan et al.
System: The UNT Digital Library
Ultra-high efficiency multilayer blazed gratings through deposition kinetic control (open access)

Ultra-high efficiency multilayer blazed gratings through deposition kinetic control

Diffraction efficiency of multilayer coated blazed gratings (MBG) strongly depends on the perfection of the saw-toothshaped layers in the overall composite structure. Growth of multilayers on saw-tooth substrates should be carefully optimized in order to reduce groove profile distortion and at the same time to avoid significant roughening of multilayer interfaces. In this work we report on a new way to optimize growth of sputter-deposited Mo/Si multilayers on saw-tooth substrates through variation of the sputtering gas pressure. A new record for diffraction efficiency of 44% was achieved for a optimized MBG with groove density of 5250 lines/mm at the wavelength of 13.1 nm.
Date: January 23, 2012
Creator: Anderson, Erik; Gullikson, Eric; Salmassi, Farhad; Warwick, Tony; Yashchuk, Valeriy & Padmore, Howard
System: The UNT Digital Library
MACHINERY RESONANCE AND DRILLING (open access)

MACHINERY RESONANCE AND DRILLING

New developments in vibration analysis better explain machinery resonance, through an example of drill bit chattering during machining of rusted steel. The vibration of an operating drill motor was measured, the natural frequency of an attached spring was measured, and the two frequencies were compared to show that the system was resonant. For resonance to occur, one of the natural frequencies of a structural component must be excited by a cyclic force of the same frequency. In this case, the frequency of drill bit chattering due to motor rotation equaled the spring frequency (cycles per second), and the system was unstable. A soft rust coating on the steel to be drilled permitted chattering to start at the drill bit tip, and the bit oscillated on and off of the surface, which increased the wear rate of the drill bit. This resonant condition is typically referred to as a motor critical speed. The analysis presented here quantifies the vibration associated with this particular critical speed problem, using novel techniques to describe resonance.
Date: January 23, 2010
Creator: Leishear, R. & Fowley, M.
System: The UNT Digital Library
PERFORMANCE ASSESSMENT ASSISTANCE ACTIVITIES IN THE DOE COMPLEX (open access)

PERFORMANCE ASSESSMENT ASSISTANCE ACTIVITIES IN THE DOE COMPLEX

The United States Department of Energy Office of Environmental Management (DOE-EM) has established a Performance Assessment Community of Practice (PA CoP) to foster the sharing of information among performance assessment (PA) and risk assessment practitioners, regulators and oversight personnel. The general intent is to contribute to continuous improvement in the consistency, technical adequacy and quality of implementation of PAs and risk assessments around the DOE Complex. The PA CoP activities have involved commercial disposal facilities and international participants to provide a global perspective. The PA CoP has also sponsored annual technical exchanges as a means to foster improved communication and to share lessons learned from on-going modelling activities. The PA CoP encourages activities to provide programmatic and technical assistance in the form of sharing experience and lessons learned with practitioners during the development of PAs and risk assessments. This assistance complements DOE-EM reviews through the Low-Level Waste Disposal Facility Federal Review Group (LFRG) that are conducted after modelling efforts are completed. Such up-front assistance is providing additional value in terms of improving consistency and sharing of information. There has been a substantial increase in the amount of assistance being provided. The assistance has been well received by practitioners and regulators …
Date: January 23, 2012
Creator: Seitz, R.
System: The UNT Digital Library
Phenotypic developmental plasticity induced by preincubation egg storage in chicken embryos (Gallus gallus domesticus) (open access)

Phenotypic developmental plasticity induced by preincubation egg storage in chicken embryos (Gallus gallus domesticus)

This article investigates how preincubation egg storage conditions (temperature, duration, hypoxia, and hypercapnia) affects viability, body mass, and physiological variables and functions in day 15 chicken embryos.
Date: January 23, 2016
Creator: Branum, Sylvia R.; Tazawa, Hiroshi & Burggren, Warren W.
System: The UNT Digital Library
THE IMPACT OF OZONE ON THE LOWER FLAMMABLE LIMIT OF HYDROGEN IN VESSELS CONTAINING SAVANNAH RIVER SITE HIGH LEVEL WASTE (open access)

THE IMPACT OF OZONE ON THE LOWER FLAMMABLE LIMIT OF HYDROGEN IN VESSELS CONTAINING SAVANNAH RIVER SITE HIGH LEVEL WASTE

The Savannah River Site, in conjunction with AREVA Federal services, has designed a process to treat dissolved radioactive waste solids with ozone. It is known that in this radioactive waste process, radionuclides radiolytically break down water into gaseous hydrogen and oxygen, which presents a well defined flammability hazard. Flammability limits have been established for both ozone and hydrogen separately; however, there is little information on mixtures of hydrogen and ozone. Therefore, testing was designed to provide critical flammability information necessary to support safety related considerations for the development of ozone treatment and potential scale-up to the commercial level. Since information was lacking on flammability issues at low levels of hydrogen and ozone, a testing program was developed to focus on filling this portion of the information gap. A 2-L vessel was used to conduct flammability tests at atmospheric pressure and temperature using a fuse wire ignition source at 1 percent ozone intervals spanning from no ozone to the Lower Flammable Limit (LFL) of ozone in the vessel, determined as 8.4%(v/v) ozone. An ozone generator and ozone detector were used to generate and measure the ozone concentration within the vessel in situ, since ozone decomposes rapidly on standing. The lower flammability …
Date: January 23, 2013
Creator: Sherburne, Carol; Osterberg, Paul; Johnson, Tom & Frawely, Thomas
System: The UNT Digital Library
Rate constant for the reaction C₂H₅ + HBr → C₂H₆ + Br (open access)

Rate constant for the reaction C₂H₅ + HBr → C₂H₆ + Br

Article on the rate constant for the reaction C2H5 + HBr → C2H6 + Br.
Date: January 23, 2012
Creator: Golden, David M.; Peng, Jingping; Goumri, Abdellatif; Yuan, Jessie & Marshall, Paul
System: The UNT Digital Library
Artificially structured boundary for confinement of effectively unmagnetized cryogenic antimatter plasmas (open access)

Artificially structured boundary for confinement of effectively unmagnetized cryogenic antimatter plasmas

The article is from conference proceedings that discuss an artificially structured boundary (ABS) considered to consist of a spatially periodic arrangement of electrostatically plugged magnetic cusps. As envisioned, a non-neutral positron plasma could be confined by an ASB along its edge, and the space charge of the positron plasma would serve to confine an antiproton plasma. If the conditions of the two-species plasma are suitable, production of antihydrogen via three-body recombination for antimatter gravity studies may be possible.
Date: January 23, 2018
Creator: Hedlof, R. M. & Ordonez, Carlos A.
System: The UNT Digital Library
Particular Emergency Department for Seniors (open access)

Particular Emergency Department for Seniors

Editorial discusses and compares services provided for senior people at emergency departments and geriatric emergency departments.
Date: January 23, 2012
Creator: Amini, Reza
System: The UNT Digital Library
Development of MMC Gamma Detectors for Nuclear Analysis (open access)

Development of MMC Gamma Detectors for Nuclear Analysis

None
Date: January 23, 2014
Creator: Bates, C. R.; Pies, C.; Kempf, S.; Gastaldo, L.; Fleischmann, A.; Enss, C. et al.
System: The UNT Digital Library
Hadron Spectroscopy and Dynamics from Light-Front Holography and Conformal Symmetry (open access)

Hadron Spectroscopy and Dynamics from Light-Front Holography and Conformal Symmetry

None
Date: January 23, 2014
Creator: de Teramond, Guy F.; Brodsky, Stanley J. & Dosch, Hans Gunter
System: The UNT Digital Library
A chemical genetic screen uncovers a small molecule enhancer of the N-acylethanolamine degrading enzyme, fatty acid amide hydrolase, in Arabidopsis (open access)

A chemical genetic screen uncovers a small molecule enhancer of the N-acylethanolamine degrading enzyme, fatty acid amide hydrolase, in Arabidopsis

This article demonstrates the feasibility of using an unbiased chemical genetic approach to identify new pharmacological tools for manipulating FAAH- and NAE-mediated physiological processes in plants.
Date: January 23, 2017
Creator: Khan, Bibi Rafeiza; Faure, Lionel; Chapman, Kent D. & Blancaflor, Elison B.
System: The UNT Digital Library