Simple Apparatus for Adding Small Amounts of Powder Materials under an Inert Atmosphere

Addition of reactants under an inert atmosphere is a fundamental but extremely important technique in synthetic chemistry. Although this is achievable in many cases by using a glove box or a Schlenk-and-syringe technique, the direct addition of powder (solid) materials without contamination by air or moisture has been difficult, especially in the later stages of a reaction. Here, we offer a simple and small apparatus to realize powder addition with easy handling. Use of this apparatus permitted one-pot glycosylation reactions that required extremely dry conditions to be performed in a highly reproducible manner.

High-Reynolds-number turbulence in small apparatus: grid turbulence in cryogenic liquids

Liquid helium at 4.2 K has a viscosity that is about 40 times smaller than that of water at room temperature, and about 600 times smaller than that of air at atmospheric pressure. It is therefore a convenient fluid for generating in a table-top apparatus turbulent flows at high Reynolds numbers that require large air and water facilities. Here, we produce turbulence behind towed grids in a liquid helium chamber that is 5 cm2 in cross-section at mesh Reynolds numbers of up to 7×105. Liquid nitrogen is intermediate in its viscosity as well as refrigeration demands, and so we also exploit its use to generate towed-grid turbulence up to mesh Reynolds number of about 2×104. In both instances, we map two-dimensional fields of velocity vectors using particle image velocimetry, and compare the data with those in water and air.

Spinal Fixator for the Management of Spinal Injury (the Mechanical Rationale)

The goal of successful treatment of spinal injury is to achieve a stable pain-free spine with no deformity and also the complete anterior decompression of the cord for maximum neurological recovery, the minimum bed-ridden time and hospitalization, and reduction of complications and expenses. A special ‘spinal fixator’ has been developed to fulfill these aims. It is a small apparatus with two components: a stabilizer to fix the adjacent vertebrae and a turn-buckle part to produce compression. Extensive biomechanical tests on cadavers confirmed that this appliance produced secure stability on the broken spine. It will simply replace the broken bodies through an anterolateral approach, restore the height of the body vertebrae for normal weight-bearing, and securely stabilize the broken spine for early mobility and rehabilitation; and finally, it will provide the chance to decompress the cord anteriorly for a better recovery. In this way the patient will be able to sit one day after the operation, to stand (with or without brace) in two to three weeks, and leave the hospital in three to six weeks after the operation. Details of engineering rational bases of this technique are described.

An Inexpensive Unit for Demonstrations of the Phi and Autokinetic Phenomena

This paper describes a small apparatus for demonstrating the phi phenomenon and the autokinetic effect and provides circuit diagrams whereby the apparatus may be constructed.