Synthesis of cis- and trans-2,5-disubstituted tetrahydrofurans by a tandem dihydroxylation-SN2 cyclization sequence

[reaction: see text] Dihydroxylation of delta- and epsilon-mesyloxy alpha,beta-unsaturated esters proceeds with in situ cyclization to afford 2,5-disubstituted and 2,3,5-trisubstituted tetrahydrofurans.     

Negative and positive mass spectra of some substituted trinitromethanes

The negative and positive ion mass spectra of a series of substituted trinitroalkanes (nitroform, tetranitro methane, methyl, fluoro, chloro, bromo and iodo-trinitro methane) have been measured with an Aatlas CH-4 Mass Spectrometer, under varying electron energies from 70 over the total range at which ions are produced. The modes of decomposition of the compounds are presented. A few metastable transitions are observable in the negative ion spectra, but only at high electron energies (ion pair region) and are very low in intensity. the negative and positive ion clastograms of these polynitro compounds showed little parent-daughter ion correlation. Finally, the negative ions formed appear to contain excess amounts of kinetic energy even at low electron energies; as a retult there is a great deal of overlap in the various mechanisms for the formation of negative ions.     

Gravimetric determination of gold with di-2-thienylketoxime

Di-2-thienylketoxime may be used as a gravimetric reagent to determine gold. The error is of the order of ± 0.3%. There are few interfering ions and simple methods may be used to eliminate these.     

Verification and validation of a winter driving simulator

A full vehicle dynamics simulator was constructed in SimCreator^® for the Cold Regions Research and Engineering Laboratory (CRREL) Instrumented Vehicle (CIV) and was used to investigate and validate the newly developed Vehicle Terrain Interaction (VTI) code. The VTI code replaces the tire component of the simulated vehicle, in the Driver and Motion Simulator (DMS), allowing it to report back realistic values while driving on various types of terrain surfaces such as mud, snow, ice, and pavement. The validation effort within this paper is focused on the winter (snow and ice) parts of the VTI code. The outputs from the Engineering Research and Development Center (ERDC) and the DMS VTI codes were validated through field experiments and against the North Atlantic Treaty Organization (NATO) Reference Mobility Model (NRMM). The DMS VTI code can be used with different vehicle models, providing the US. Army with a valuable asset that will allow simulation of existing or conceptual, manned or autonomous, ground vehicle performance for acquisition, planning, or training. This information, along with some basic terrain information, will allow troops to plan the fastest and most effective way of getting to a desired location, while minimizing the possibility of being delayed because of the terrain conditions.     

Special Issue Article: Preparing for the 21st Century: The Status of Quantitative Literacy in the United States

This article articulates and operationalizes a framework for investigating the level of quantitative literacy in the United States. Quantitative literacy is defined in terms of mathematical content knowledge, mathematical reasoning, understanding of the social impact and utility of mathematics, understanding the nature and historical development of mathematics, and mathematical disposition‐Data from the Third International Mathematics and Science Study are used to document the level of quantitative literacy in the US. Results suggest that, although students in the US seem to possess an awareness of the usefulness of mathematics and have positive dispositions toward mathematics, they fall short in their understanding of the nature of mathematics and an ability to apply their content knowledge to everyday situations. Suggestions for curriculum and instruction that align with the framework for promoting quantitative literacy are offered.     

High‐resolution slice selection NMR for the measurement of CO2 diffusion under non‐equilibrium conditions

We present a simple and an efficient approach using spatially selective NMR to investigate solvation and diffusion of CO₂ in ionic liquids. The techniques demonstrated here are shown as novel and effective means of studying solvated gas dynamics under non‐equilibrium conditions without the need for conventional high power gradients. Copyright © 2014 John Wiley & Sons, Ltd.