Alejandro Bugacov

Nanoparticle manipulation by mechanical pushing: underlying phenomena and real-time monitoring

Experimental results that provide new insights into nanomanipulation phenomena are presented. Reliable and accurate positioning of colloidal nanoparticles on a surface is achieved by pushing them with the tip of an atomic force microscope under control of software that compensates for instrument errors. Mechanical pushing operations can be monitored in real time by acquiring simultaneously the cantilever deflection and the feedback signal (cantilever non-contact vibration amplitude). Understanding of the underlying phenomena and real-time monitoring of the operations are important for the design of strategies and control software to manipulate nanoparticles automatically. Manipulation by pushing can be accomplished in a variety of environments and materials. The resulting patterns of nanoparticles have many potential applications, from high-density data storage to single-electron electronics, and prototyping and fabrication of nanoelectromechanical systems.

Nanorobotic assembly of two-dimensional structures

Precise control of the structure of matter at the nanometer scale will have revolutionary implications for science and technology. Nanoelectromechanical systems (NEMS) will be extremely small and fast, and have applications that range from cell repair to ultrastrong materials. This paper describes the first steps towards the construction of NEMS by assembling nanometer-scale objects using a scanning probe microscope as a robot. Our research takes an interdisciplinary approach that combines knowledge of macrorobotics and computer science with the chemistry and physics of phenomena at the nanoscale. We present experimental results that show how to construct arbitrary patterns of gold nanoparticles on a mica or silicon substrate, and describe the underlying technology. We also discuss the next steps in our research, which are aimed at producing connected structures in the plane, and eventually three-dimensional nanostructures.

Integrating geographic information systems, spatial digital libraries and information spaces for conducting humanitarian assistance and disaster relief operations in urban environments

The GeoWorlds system integrates geographic information systems, spatial digital libraries and other information analysis, retrieval and collaboration tools. It supports multiple applications ranging from intelligence gathering to urban planning, to crisis management and response. Teams can rapidly assemble collections of document-based information from the World-Wide Web and other specialized information sources, visualize geospatial distribution of these collections and monitor events that might change conclusions or decisions formed on the basis of an initial information set. This functionality is provided within a framework that supports both synchronous and asynchronous collaboration over finding, filtering and organizing information and presenting it in a rich visualization environment.

GeoWorlds: integrating GIS and digital libraries for situation understanding and management

Abstract Helping organizations to marshal, analyze, discuss, and act on all of the available information about a situation playing out over space and time is a critical problem. GeoWorlds (http://www.isi.edu/geoworlds) is a component-based information management system that addresses this issue. It brings together information analysis, retrieval and collaboration tools and integrates digital library, geographic information systems (GIS), and remote sensor data management technologies. It provides three key services: 1) rapidly assembling a custom repository of geographic information about a region, 2) bi-directionally linking it to collections of document-based information from the World-Wide Web, and 3) monitoring real-time sensor data for information that might change conclusions or decisions formed on the basis of this rich information set. GeoWorlds framework enables synchronous and asynchronous collaboration over finding, filtering, organizing and visualizing the needed information.

Voxels: volume-enclosing microstructures

This paper presents results on the development and fabrication of hollow 3D, programmable-volume, micro-scale, artificial, non-biological volume cells or voxels. The standardized silicon wafer processing method PolyMUMPs® was used to construct a variety of polysilicon devices capable of being folded from two-dimensional shapes into three-dimensional regular solids with dimensions in the order of 40–80 µm per side. Folding of the devices was performed by a combination of magnetic and surface tension forces in water. Complete closure of pyramidal structures with dimensions down to 40 µm per side was achieved, as well as folding of five-sided boxes and half-dodecahedrons (lotuses) with dimensions down to 40 µm per side.