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Nanoparticles (NPs) are applied in a wide range of processes, and their use continues to increase. Fluidization is one of the best techniques available to disperse and process NPs. NPs cannot be fluidized individually; they fluidize as very porous agglomerates. The objective of this article is to review the developments in nanopowder fluidization. Often, it is needed to apply an assistance method, such as vibration or microjets, to obtain proper fluidization. These methods can greatly improve the fluidization characteristics, strongly increase the bed expansion, and lead to a better mixing of the bed material. Several approaches have been applied to model the behavior of fluidized nanopowders. The average size of fluidized NP agglomerates can be estimated using a force balance or by a modified Richardson and Zaki equation. Some first attempts have been made to apply computational fluid dynamics. Fluidization can also be used to provide individual NPs with a thin coating of another material and to mix two different species of nanopowder. The application of nanopowder fluidization in practice is still limited, but a wide range of potential applications is foreseen.

Nanoparticles (NPs) are applied in a wide range of processes, and their use continues to increase. Fluidization is one of the best techniques available to disperse and process NPs. NPs cannot be fluidized individually; they fluidize as very porous agglomerates. The objective of this article is to review the developments in nanopowder fluidization. Often, it is needed to apply an assistance method, such as vibration or microjets, to obtain proper fluidization. These methods can greatly improve the fluidization characteristics, strongly increase the bed expansion, and lead to a better mixing of the bed material. Several approaches have been applied to model the behavior of fluidized nanopowders. The average size of fluidized NP agglomerates can be estimated using a force balance or by a modified Richardson and Zaki equation. Some first attempts have been made to apply computational fluid dynamics. Fluidization can also be used to provide individual NPs with a thin coating of another material and to mix two different species of nanopowder. The application of nanopowder fluidization in practice is still limited, but a wide range of potential applications is foreseen.

Nanoparticles (NPs) are applied in a wide range of processes, and their use continues to increase. Fluidization is one of the best techniques available to disperse and process NPs. NPs cannot be fluidized individually; they fluidize as very porous agglomerates. The objective of this article is to review the developments in nanopowder fluidization. Often, it is needed to apply an assistance method, such as vibration or microjets, to obtain proper fluidization. These methods can greatly improve the fluidization characteristics, strongly increase the bed expansion, and lead to a better mixing of the bed material. Several approaches have been applied to model the behavior of fluidized nanopowders. The average size of fluidized NP agglomerates can be estimated using a force balance or by a modified Richardson and Zaki equation. Some first attempts have been made to apply computational fluid dynamics. Fluidization can also be used to provide individual NPs with a thin coating of another material and to mix two different species of nanopowder. The application of nanopowder fluidization in practice is still limited, but a wide range of potential applications is foreseen.

Nanoparticles (NPs) are applied in a wide range of processes, and their use continues to increase. Fluidization is one of the best techniques available to disperse and process NPs. NPs cannot be fluidized individually; they fluidize as very porous agglomerates. The objective of this article is to review the developments in nanopowder fluidization. Often, it is needed to apply an assistance method, such as vibration or microjets, to obtain proper fluidization. These methods can greatly improve the fluidization characteristics, strongly increase the bed expansion, and lead to a better mixing of the bed material. Several approaches have been applied to model the behavior of fluidized nanopowders. The average size of fluidized NP agglomerates can be estimated using a force balance or by a modified Richardson and Zaki equation. Some first attempts have been made to apply computational fluid dynamics. Fluidization can also be used to provide individual NPs with a thin coating of another material and to mix two different species of nanopowder. The application of nanopowder fluidization in practice is still limited, but a wide range of potential applications is foreseen.

Nanoparticles (NPs) are applied in a wide range of processes, and their use continues to increase. Fluidization is one of the best techniques available to disperse and process NPs. NPs cannot be fluidized individually; they fluidize as very porous agglomerates. The objective of this article is to review the developments in nanopowder fluidization. Often, it is needed to apply an assistance method, such as vibration or microjets, to obtain proper fluidization. These methods can greatly improve the fluidization characteristics, strongly increase the bed expansion, and lead to a better mixing of the bed material. Several approaches have been applied to model the behavior of fluidized nanopowders. The average size of fluidized NP agglomerates can be estimated using a force balance or by a modified Richardson and Zaki equation. Some first attempts have been made to apply computational fluid dynamics. Fluidization can also be used to provide individual NPs with a thin coating of another material and to mix two different species of nanopowder. The application of nanopowder fluidization in practice is still limited, but a wide range of potential applications is foreseen.

Combating WMD Journal is published semi-annual by the Army Nuclear and CWMD Agency (USANCA). Articles include topics on deterrence, weapons of mass destruction, the Cold War, history of chemical warfare, nuclear engineering, etc., The original document contains color images. All DTIC reproductions will be in black and white.

Welcome to the first issue of the US Army Nuclear and Combating WMD Journal. Since my last writing, USANCA continues to improve its planning and analysis capabilities to assist the Army Service Component Commands, in coordination and support of the Army Staff. We are also increasingly engaged in the Army's capabilities process, in concert with the Joint Capabilities Integration and Development System (JCIDS) process, and through international forums as well. I want to highlight just a few of the activities and issues our Army is now addressing in these areas. Two Combating WMD Planning Assistance Teams are forming to assist Echelon Above Corps Army elements with CWMD planning capability. Their initial focus will be the Pacific and domestically in the US. Key to their success is close coordination with the Defense Threat Reduction Planners (for COCOM level integration) and HODA Strategy, Plans and Policy Elements (for Army Component integration). Additionally, we are providing CWMD subject matter experts to the Battle Command Training Program in support of exercises held at Corps level and above. Information from these interactions is used by USANCA in reviewing Joint Capability documents as well as guiding analysis efforts to better understand the operational impact of specific WMD challenges. One key to successful integration of CWMD tasks and strategy is the consideration of Security Cooperation efforts in light of those called for in the Contingency Planning Guidance. Beyond the obvious `Phase 0' connection, the demand on Army resources across both areas is viewed concurrently providing a more holistic perspective., The original document contains color images. All DTIC reproductions will be in black and white. Published in Combating WMD Journal, Issue 1, p1-63, 2007.

The introduction of high-tech equipment into the Army inventory has substantially increased battle effectiveness, reduced personnel requirements, and in some cases allowed the replacement of several manned operational platforms and systems with unmanned equivalents. The continued trend toward digital robotics in the battlespace has become extremely attractive to military planners, so much so that future warfighters are expected to employ a considerable number of unmanned platforms and systems. Up to this point in time, however, nuclear hardening criteria have been applied principally to manned systems and have been balanced to the nuclear survivability of the operating crew. This paper provides the rationale for establishing reasonable nuclear hardening criteria for objective force unmanned mission critical equipment. It starts with the survivability requirement and then identifies the process used to establish criteria for five unmanned equipment classes. Also included are the factors to be considered and the steps to be taken to establish hardening criteria for all nuclear weapons effects (NWE) and for all weapon yields of interest. The paper concludes with an application of the process to a hypothetical system. Details given in this paper form the basis for proposed Quadripartite Standardization Agreement (QSTAG) 2041, a standard for the Armies of the United States, the United Kingdom, Canada, and Australia., Presented at the International Command and Control Research and Technology Symposium (8th), ICCRTS '03, held in Washington, DC on 17-19 Jun 2003. The original document contains color images.

In this paper, a unified protection methodology is applied to a digital mobile C4I platform subjected to several human-generated and nature-generated EM environments and effects. The unclassified values for self-induced electromagnetic interference (EMI), EM radiation (EMR), electrostatic discharge (ESD), near-strike lightning, and high-altitude EM pulse (HEMP) came from MIL-STD-464 and several commercial standards. By applying this methodology the EM protection requirements were estimated to be 70 dB enclosure port protection for frequencies between 100 MHz and 5 GHz, and 80 dB penetration port protection on the phone line for frequencies dependent upon the length of the phone line used. This EM protection strategy is both useful and cost effective to coalition forces, since validation testing and maintenance/surveillance testing to meet international standards reduce to simple, low-cost shield and penetration protection tests that can be conducted anywhere, even with the system operating. The application of this protection approach in the original system circuit design significantly reduces the number of breadboard and brassboard tests. Such protection also allows component replacement within the barrier, once the new component immunity level has been measured.

The single crystal epitaxial layer ohmic contacts are very promising in the fabrication of shallow junction nanoelectronic and mesoscopic devices based on III-V compounds. A single crystal Ge film is grown epitaxially on GaAs or InGaP lattice matched to GaAs and a Au or Pd layer is deposited on top of it using an Ultra High Vacuum (10(exp -9 -10 Torr) Electron Beam (UHV E-Beam) deposition system. The interface between the Ge and thermally cleaned GaAs or InGaP is almost atomically abrupt, smooth and oxide free, and there is a minimum of disruption of the underlying layers. When deposited at an appropriate temperature, the metals are highly oriented and have large grains. They can be diffused through the Ge film to initiate the formation on an ohmic contact in a controlled manner. A detailed analysis of interface quality, crystal structure and defect propagation in GaAs/Ge/Au, GaAs/Ge/Pd, InGaP/Ge structures is presented. High resolution Transmission Electron Microscopy (HRTEM), Double Crystal X-ray Diffraction (DXRD), Rutherford Backscattering Spectroscopy (RBS) and Auger Electron Spectroscopy (AES) were used to characterize the materials.

The charge transport dosimeter, an instrument capable of measuring doses of gamma rays and fast neutrons delivered to personnel, is intended as a second generation Army tactical dosimeter, replacing the present IM185. The instrument's response to gamma rays is based on the tendency of high atomic number materials to reflect the energetic electrons produced within matter by gamma rays, causing a positive charge to collect on a thin central conductor surrounded by a low atomic number insulator. It is made sensitive to fast neutrons as well by surrounding the collector with a hydrogenous radiator. By proper selection of collector and radiator dimensions and compositions, its quantum energy response and neutron-to-gamma response ratio can be tailored to match a wide choice of desired characteristics. A number of experimental models of the charge transport dosimeter have been built and successfully tested on gamma rays and fast neutrons at various dose delivery rates. Results show that the instrument promises to satisfy all Army requirements for a tactical dosimeter while substantially reducing both production and maintenance costs., Sponsored in part by Defense Civil Preparedness Agency, Washington, D.C. Presented at the Army Science Conference (10th), Military Academy, West Point, N.Y., 23 Jun 76.

The present investigation has shown to be in very good agreement with a broad spectrum of numerical Navier-Stokes solutions for the flow past smoothly contoured bodies in the intermediate Reynolds number range where the body is semi-infinite or a steady laminar wake exists. The theory can be easily applied to many boundary shapes for which published numerical Navier-Stokes solutions currently do not exist. The important fundamental contribution of the study is the improved understanding of the role and construction of the displacement body and the effect of centrifugal forces in thick viscous layers.

An aluminum threshold dosimetry technique has been adopted to measure neutron fluences at the Fort Hancock 14-MeV neutron source operated by the ECOM Nuclear Radiation Facility. A procedure is outlined for those wishing to measure dose delivered to irradiated samples. A description of the source (including its calibration) is provided, as is a theoretical clarification of the dosimetry technique.

As part of an investigation of the physical basis underlying aspects of MOS processing technology, we have studied the transport mechanism by which water diffuses through thin SiO2 films. This process is responsible for the formation of oxide layers on silicon wafers by means of thermal steam oxidation, which is frequently employed in the manufacture of integrated circuit devices. We have performed tracer diffusion measurements involving network 180, demonstrating the importance of oxygen exchange between the Si02 network and molecularly dissolved water. We have found that in the presence of water, bound network oxygen diffuses through Si02 as a constituent of molecularly dissolved water. Employing methods common to state-of-the-art semiconductor technology, the central region within a thermal oxide layer grown on silicon was enriched with immobile 180 by ion implantation. After heating in atmospheres with different water contents, the extent of 180 diffusion was determined by observing changes in the concentration profile (i.e. the chemical concentration as a function of depth) of implanted 180 by means of nuclear resonance profiling.

An absolute dosimetry system was designed to determine the effect of differences between nuclear weapon simulator gamma-ray spectra and the spectra of standard calibration sources on the accuracy of simulator dosimetry systems. This system, employing a set of portable equilibrium calorimeters of widely differing composition, was constructed at ECOM, Fort Monmouth, NJ, and successfully tested at the Air Force Weapons Laboratory (AFWL), Transient Radiation Effects Facility (TREF), Albuquerque, NM. The test results were consistent with a calculated prediction of a 60% variation in deposited dose with atomic number characteristic of the gamma-ray spectra of TREF simulators. It is suggested that the output spectra of these machines be hardened via selective absorption of low energy photons by a layer of high atomic number material interposed between the faceplate and objects being exposed. The layer should be thick enough to yield a spectrum for which the variation of dose over atomic number is within the uncertainty of the dosimetry system used, permitting the use of any dosimetric materials. (Author)

Irradiation of an insulator by gamma rays can produce voltage and charge buildups near thin layers of foreign material within the insulator. Measurements have been made of the current produced as a function of atomic nuber and thickness of the perturbing layer. Current was also measured as a function of separation from the perturbation, as was voltage buildup within the insulator close to the perturbation. (Author)

While conducting radiation experiments using polyvinyl chloride and photographic film as dosimeters the author noticed anomalous 'hot spots' in dose delivered to regions where there was a perturbation in the atomic number Z close to the dosimeter. These increases in local dose were strongly dependent on the direction of the incident radiation and could be observed even when the perturbation was a very thin layer of different Z material. Such perturbations can affect measurements of gamma and X-ray doses and may be responsible for serious errors in dosimetry if one is not aware of their existence. This effect is discussed in the report.