Preparing a Celadonite Electron Source and Estimating Its Brightness.

The electron celadonite source described here performs well in a low-energy electron point-source projection microscope in long-range imaging. It presents major advantages compared to sharp metal tips. Its robustness affords a lifetime of months and it can be used under relatively high pressure.

A low-energy electron point-source projection microscope not using a sharp metal tip performs well in long-range imaging.

A low-energy electron point-source projection microscope that uses a metal/insulator structure as source instead of a sharp metal needle is presented. By combining this source with an electron optical lens and a high spatial resolution image detector, performances comparable to those of a normal electron projection microscope are easily accessible and presented here. The accessible electron energy range extends from 100 eV to 1000 eV.

High spatial resolution detection of low-energy electrons using an event-counting method, application to point projection microscopy.

An event-counting method using a two-microchannel plate stack in a low-energy electron point projection microscope is implemented. 15 μm detector spatial resolution, i.e.

Localizing and inducing primary nucleation.

Do the differing properties of materials influence their nucleation mechanisms? We present different experimental approaches to study and control nucleation, and shed light on some of the factors affecting the nucleation process.

Practical physics behind growing crystals of biological macromolecules.

The aim of this review is to provide biocrystallographers who intend to tackle protein-crystallization with theory and practical examples. Crystallization involves two separate processes, nucleation and growth, which are rarely completely unconnected. Here we give theoretical background and concrete examples illustrating protein crystallization.

Predictive nucleation of crystals in small volumes and its consequences.

We propose another way of getting to the bottom of nucleation by using finite volume systems. Here we show, using a sharp tip, that a single nucleation event is launched as soon as the tip touches the supersaturated confined metastable solution. We thus control spatial and temporal location and demonstrate that confinement allows us to carry out predictive nucleation experiments.

Permeability profiles in granular aquifers using flowmeters in direct-push wells.

Numerical hydrogeological models should ideally be based on the spatial distribution of hydraulic conductivity (K), a property rarely defined on the basis of sufficient data due to the lack of efficient characterization methods. Electromagnetic borehole flowmeter measurements during pumping in uncased wells can effectively provide a continuous vertical distribution of K in consolidated rocks. However, relatively few studies have used the flowmeter in screened wells penetrating unconsolidated aquifers, and tests conducted in gravel-packed wells have shown that flowmeter data may yield misleading results.

The influence of topology on hydraulic conductivity in a sand-and-gravel aquifer.

A field experiment consisting of geophysical logging and tracer testing was conducted in a single well that penetrated a sand-and-gravel aquifer at the U.S. Geological Survey Toxic Substances Hydrology research site on Cape Cod, Massachusetts.

Lensless electron reflection microscopy using a coaxial point-source structure.

A lensless image of the surface of a crystal is obtained by the reflection on this surface of a low-energy electron beam originated from a point source integrated in a coaxial structure. The point source is a sharp field emission tip and a free propagation of reflected electrons results from the shielding of the tip voltage provided by the coaxial structure. Images are obtained for an incidence angle between 3 and 45 degrees and for nA incident currents with a kinetic energy down to 40 V.

Use of an electromagnetic seepage meter to investigate temporal variability in lake seepage.

A commercially available electromagnetic flowmeter is attached to a seepage cylinder to create an electromagnetic seepage meter (ESM) for automating measurement of fluxes across the sediment/water interface between ground water and surface water. The ESM is evaluated through its application at two lakes in New England, one where water seeps into the lake and one where water seeps out of the lake. The electromagnetic flowmeter replaces the seepage-meter bag and provides a continuous series of measurements from which temporal seepage processes can be investigated.