Bringing Math to Life: Provide Students Opportunities to Connect their Lives to Math

Math journals provide students with opportunities to articulate their understanding of math concepts and/or their frustrations with the gaps in those understandings. Their use supports metacognitive thinking to enhance understanding and application. This study took a look at the use of math journals by fourth grade students as a conduit for critical thinking, reflection, and real world math application. For this study, student journal entries consisted of identification of a real-life event, the use of a problem-solving strategy learned during class instruction, narrative of both the problem’s description as well as the rationale for choosing the problem, and the use of a numeric or pictorial model with solution. Students shared his/her journal entry with the entire class. Through this research, I witnessed evidence of growth in mathematical understanding, computing and a deeper connection to math’s many real-life applications in the lives of elementary students

Free-field propagation of high intensity noise

Research on high intensity (finite amplitude) acoustic waves shows that nonlinear distortion effects generally result in a shift of energy to higher frequencies. The higher intensities associated with supersonic jets would therefore indicate that high frequency enhancement of the spectrum should occur, resulting in the differences observed between subsonic and supersonic jets. A 10,000 acoustic watt source installed in an anechoic chamber generates sound levels such that acoustic shocks are readily observable. Dual frequency excitation of the source produces a strong parametric effect with a difference frequency comparable in level to the primary frequency. The test set up and recording equipment being used to determine the finite amplitude noise representative of an actual supersonic jet are described as well as the development of a computer program based on Burger's equation. The spectra of 1/2 octave band, 1 kHz sine wave, and dual frequency input and output are presented in graphs along with waveforms at Z = .025, 0.1, and 1.0

Formation of plasma around a small meteoroid: 1. Kinetic theory

This article is a companion to Dimant and Oppenheim [2017] https://doi.org/10.1002/2017JA023963.This paper calculates the spatial distribution of the plasma responsible for radar head echoes by applying the kinetic theory developed in the companion paper. This results in a set of analytic expressions for the plasma density as a function of distance from the meteoroid. It shows that at distances less than a collisional mean free path from the meteoroid surface, the plasma density drops in proportion to 1/R where R is the distance from the meteoroid center; and, at distances much longer than the mean‐free‐path behind the meteoroid, the density diminishes at a rate proportional to 1/R2. The results of this paper should be used for modeling and analysis of radar head echoes.This work was supported by NSF grant AGS-1244842. (AGS-1244842 - NSF

Drilling and coring methods that minimize the disturbance of cuttings, core, and rock formation in the unsaturated zone, Yucca Mountain, Nevada

A drilling-and-casing method (Odex 115 system) utilizing air as a drilling fluid was used successfully to drill through various rock types within the unsaturated zone at Yucca Mountain, Nevada. This paper describes this method and the equipment used to rapidly penetrate bouldery alluvial-colluvial deposits, poorly consolidated bedded and nonwelded tuff, and fractured, densely welded tuff to depths of about 130 meters. A comparison of water-content and water-potential data from drill cuttings with similar measurements on rock cores indicates that drill cuttings were only slightly disturbed for several of the rock types penetrated. Coring, sampling, and handling methods were devised to obtain minimally disturbed drive core from bouldery alluvial-colluvial deposits. Bulk-density values obtained from bulk samples dug from nearby trenches were compared to bulk-density values obtained from drive core to determine the effects of drive coring on the porosity of the core. Rotary coring methods utilizing a triple-tube core barrel and air as the drilling fluid were used to obtain core from welded and nonwelded tuff. Results indicate that the disturbance of the water content of the core was minimal. Water-content distributions in alluvium-colluvium were determined before drilling occurred by drive-core methods. After drilling, water-content distributions were determined by nuclear-logging methods. A comparison of the water-content distributions made before and after drilling indicates that Odex 115 drilling minimally disturbs the water content of the formation rock. 10 refs., 12 figs., 4 tabs

Characterization of hydrofracture grouts for radionuclide migration

Detailed characterization of hydrofracture grouts was performed by optical microscopy, scanning electron microscopy, x-ray diffraction, and ..beta..-..gamma.. autoradiography. Laboratory-produced samples containing simulated wastes as well as actual radioactive samples of hydrofracture grout sheets obtained by core drilling were examined in this work. X-ray diffraction results revealed that both laboratory-produced samples and a core-drilled sample consisted primarily of calcium carbonate phases. Both sample types contained very small amounts of strontium or cesium wastes, neither of which could be detected by microscopic techniques. The core-drilled sample contained radioactive /sup 90/Sr, /sup 137/Cs, and /sup 60/Co that could be detected by ..beta..-..gamma.. autoradiography. The autoradiograph revealed that these radionuclides were still present in the 20-year-old grout and that they had not migrated into the trapped shale fragments

Materials used in low-level liquid waste reprocessing/treatment studies at Oak Ridge National Laboratory

The importance of effective waste management in the nuclear fuel cycle cannot be overestimated. At Oak Ridge National Laboratory (ORNL), development work in waste reprocessing and treatment includes the testing and use of various additives for the purpose of facilitating adherence to both process and regulatory performance criteria. Three waste reprocessing/treatment technologies and the associated materials are discussed in this paper: (1) suspension and transfer of sludge from waste storage tanks; (2) treatment to render a waste in compliance with regulatory requirements; and (3) fluoride-rich waste reprocessing. 7 refs., 3 figs

Observation of isotonic symmetry for enhanced quadrupole collectivity in neutron-rich 62,64,66Fe isotopes at N=40

The transition rates for the 2_{1}^{+} states in 62,64,66Fe were studied using the Recoil Distance Doppler-Shift technique applied to projectile Coulomb excitation reactions. The deduced E2 strengths illustrate the enhanced collectivity of the neutron-rich Fe isotopes up to N=40. The results are interpreted by the generalized concept of valence proton symmetry which describes the evolution of nuclear structure around N=40 as governed by the number of valence protons with respect to Z~30. The deformation suggested by the experimental data is reproduced by state-of-the-art shell calculations with a new effective interaction developed for the fpgd valence space.Comment: 4 pages, 2 figure

The role of metallic impurities in the interaction of carbon nanotubes with microwave radiation

ABSTRACT Microwave interaction with single-walled, carbon nanotubes (SWNTs) in vacuum has been shown to result in rather dramatic effects including highly ionized plasmas, high temperatures, and unique morphological changes. The mechanism for absorption of microwave energy in SWNTs is contested and centers on the role of metallic impurities. Such impurities, especially Fe, are introduced during the synthesis process as a catalyst to control the morphology of the SWNTs. In this work, the absorption of microwave energy was determined for different types of carbon nanotubes, including multi-walled and double-walled varieties. Particle Induced X-Ray Emission (PIXE) analysis was done to identify the impurities and their concentrations in the samples. Also, low-temperature gas desorption from the carbon nanotubes was studied. The results indicate that metallic impurities do not play an important role in the absorption of microwave energy by carbon nanotubes but rather structural properties dominate

Excited-state transition-rate measurements in C-18

Excited states in C-18 were populated by the one-proton knockout reaction of an intermediate energy radioactive N-19 beam. The lifetime of the first 2(+) state was measured with the Koln/NSCL plunger via the recoil distance method to be tau (2(1)(+)) = 22.4 +/- 0.9(stat)(-2.2)(+3.3)(syst) ps, which corresponds to a reduced quadrupole transition strength of B(E2; 2(1)(+) -> 0(1)(+)) = 3.64(-0.14)(+ 0.15)(stat)(-0.47)(+0.40)(syst) e(2)fm(4). In addition, an upper limit on the lifetime of a higher-lying state feeding the 2(1)(+) state was measured to be tau < 4.6 ps. The results are compared to large-scale ab initio no-core shell model calculations using two accurate nucleon-nucleon interactions and the importance-truncation scheme. The comparison provides strong evidence that the inclusion of three-body forces is needed to describe the low-lying excited-state properties of this A = 18 system

Modelos explicativos da memória prospectiva: uma revisão teórica

Neste artigo é apresentada uma revisão da literatura sobre os mecanismos cognitivos associados à memória prospectiva, organizados de acordo com a divisão das diferentes fases da recordação prospectiva (i.e., codificação, retenção e recuperação). Inicialmente, é apresentada a diversidade de dados da investigação que sustentam diferentes abordagens explicativas do fenômeno de recuperação de intenções, considerando a natureza automática ou estratégica da memória prospectiva. Em seguida, são salientadas as potenciais explicações sobre os mecanismos presentes durante o intervalo de retenção e na fase de codificação.(undefined