Tech Briefs

Cascading Failures in Coupled Distributed Power Grids and Communication Networks

Emerging distributed power grid systems will integrate tightly coupled networks, namely a power grid and a communication network, to provide distributed power monitoring and control. While distributing power monitoring and control away from a central site enhances the robustness of the power grid to multiple, dispersed failures and attacks, such communication-based distributed control schemes can introduce complex cascading failure scenarios in the face of large-scale weapons of mass destruction (WMD) attacks.

Posted in: Briefs, Physical Sciences, Telecommunications, Electric power grid, Hazards and emergency management

Implementing Interconnected Generation in Future Civil Aircraft

In addition to providing thrust, the engines on conventional civil jet airliners generate power for onboard systems and ancillary loads in the form of pneumatic, hydraulic, and electrical power. There is a move to begin replacing mechanically, hydraulically, and pneumatically powered aircraft systems with electrical equivalents, towards the ultimate goal of achieving the All-Electric Aircraft (AEA).

Posted in: Briefs, Electronics & Computers, Electrical systems, Business and general aviation aircraft

Formation and Characterization of Gold Nanoparticles

One-dimensional nanowires are of increasing interest due to their size, physical properties, and other applications in opto-electronics. For example, nanowires have already been used in light-emitting diodes and lasers, photo-detectors, resonant tunneling diodes, field-effect and single-electron transistors, and biochemical sensors. In addition, nanowires are useful because they can be grown almost dislocation-free due to their nano dimension. When dislocation- free nanowires nucleated on the substrate merge to form a continuous film, voids are left underneath, which act as sinks for dislocations, allowing other structures to be grown stress-free on top of the nano-engineered buffer layer.

Posted in: Briefs, Materials, Wiring, Nanomaterials

Carbon Nanotube Thermal Interfaces Enhanced with Sprayed-On Nanoscale Polymer Coatings

As the semiconductor industry continually strives to increase the power density of single-chip packages, thermal management remains a critical challenge toward realizing both performance and reliability metrics. One of the primary bottlenecks inhibiting effective thermal management arises from the several interfaces that can exist between the chip and heat sink. Specifically, the thermal resistance of the thermal interface materials (TIMs) that are currently used to bridge these interfaces must be decreased. Carbon nanotubes (CNTs), with their extraordinarily high axial thermal conductivity, have generated tremendous interest as candidates for providing low-resistance TIMs. A potentially scalable and low-cost process was developed that utilizes spray coating to deposit thin polymer films onto the tips of CNTs for bonding at room temperature.

Posted in: Briefs, Materials, Coatings Colorants and Finishes, Nanotechnology, Polymers, Semiconductors

Lipid Layer-Based Corrosion Monitoring on Metal Substrates

Corrosion is a deforming process that costs the United States Department of Defense (DOD) approximately $23 billion annually and accounts for 23% of all DOD maintenance. Exhaustive efforts have been made towards the detection and diagnosis of this issue; however, the problem persists. The Army’s “Go Green” initiative has opened the door for research into an environmentally friendly, biologically based corrosion monitoring technique. For this reason, novel research is being conducted on the use of lipid layers in corrosion monitoring.

Posted in: Briefs, Materials, Corrosion, Metals

Confocal Imaging System for Ultra-Fast, Three-Dimensional Transport Studies in Thermal Management Applications

The objective of this work was to develop a high-speed, three-dimensional (3D) confocal imaging system to study coupled fluidic and heat transport processes for high-performance thermal management applications. However, to successfully implement these approaches, fundamental understanding of interfacial dynamics and transport processes was necessary.

Posted in: Briefs, Physical Sciences, Imaging, Thermal management

Evaluating a Data Clustering Approach for Lifecycle Facility Control

Given the current emphasis on sustainability, there is a growing interest in monitoring various facets of building resource consumption. Building monitoring and automation systems most commonly exist as closed-loop systems for security, fire safety, water, electrical, and HVAC (Heating, Ventilation, and Air-Conditioning). One of the fundamental requirements of a mature engineering process model is the comparison of planned versus actual results for cost, risk, and quality control. For facility engineering, this implies that there must be a structured specification of building space requirements and a mechanism for detecting divergent system and occupant behaviors. Such a mechanism would have broad applicability for commissioning, energy efficiency, sustainability, diagnostics, maintenance, and a variety of other problems.

Posted in: Briefs, Physical Sciences, Sustainable development, Cost analysis, Risk management, Total life cycle management, Quality control