Noise removal in multichannel images

A adaptive filtering method, the Windrow-Hoff algorithm, for enhancing multichannel signals against aditive noise was investigated. It removes noise for multichannel images containing correlated signal compoments but uncorrelated noise components. Its potential application is the enhancement of multichannel microwave satellite images as a preprocessing step for the extraction of geophysical parameters

Restoration of multichannel microwave radiometric images

A constrained iterative image restoration method is applied to multichannel diffraction-limited imagery. This method is based on the Gerchberg-Papoulis algorithm utilizing incomplete information and partial constraints. The procedure is described using the orthogonal projection operators which project onto two prescribed subspaces iteratively. Some of its properties and limitations are also presented. The selection of appropriate constraints was emphasized in a practical application. Multichannel microwave images, each having different spatial resolution, were restored to a common highest resolution to demonstrate the effectiveness of the method. Both noise-free and noisy images were used in this investigation

From Cosmology to Cold Atoms: Observation of Sakharov Oscillations in Quenched Atomic Superfluids

Sakharov oscillations, conventionally discussed in the context of early universe evolution and the anisotropy of cosmic microwave background radiation, is the manifestation of interfering acoustic waves synchronously generated in an ideal fluid. Here we report the laboratory demonstration of Sakharov oscillations in a quenched atomic superfluid. We quench the sample by Feshbach tuning and monitor the subsequent density fluctuations at different time and length scales by in situ imaging. Sakharov oscillations are identified as the multi-peak structure in the atomic density power spectrum, resembling that of the cosmic microwave background. We also observe Sakharov oscillations in the time domain, from which we extract the energy dispersion of the superfluid, and determine the sonic horizon of the excitations

Cloning, sequencing, and expression of Brucella abortus heat shock 70 gene

Brucella abortus is a gram negative bacteria that can infect and cause serious disease in many mammals including humans. Any organism, including Brucella, that can survive as an intracellular parasite must be able to survive the stress of a foreign and often hostile environment of the host. Stress usually results in a dramatic change in gene expression including an elevated synthesis of heat shock proteins;We have subcloned, sequenced and expressed the Brucella HSP70 and the upstream sequences. The gene was put under the control of the strong tac promoter. However, when expressed, we saw a high accumulation of a 23 kDa polypeptide. Upon sequencing, this peptide was shown to be from the N-terminus of the protein;Upstream of the initiation codon of the Brucella HSP70 gene is a small ORF complete with its own initiation and termination codon and a good ribosome binding site. Various subclones were made and western blots from these showed that if the Brucella HSP70 gene is expressed without the ORF, the 23 kDa polypeptide accumulates. If the ORF is present, the protein accumulates intact. So, we concluded that this ORF is an important upstream regulatory element. Such a system has not been reported before and seems to be unique to Brucella. However, Brucella is an unusual parasite in that it can survive and multiply in the macrophage--the cell type of the immune system designed to kill it. It\u27s unknown whether this form of regulation has any relationship to survival as an intracellular parasite;To facilitate expression we also constructed seven expression vectors, pJE1-pJE7. All these plasmids were derived from pKK223-3. They all carry the M13 origin of replication to facilitate production of single stranded DNA and an expanded polycloning site to facilitate cloning. pJE1-6 are in vivo constitutive expression vectors with modified promoters such that there is a graded expression with pJE1 carrying the strongest promoter. pJE7 is designed for in vitro regulated expression using the tac promoter. This plasmid carries the lac I[superscript]q gene to prevent over expression from the tac promoter

High Accuracy Fuel Flowmeter, Phase 1

Technology related to aircraft fuel mass - flowmeters was reviewed to determine what flowmeter types could provide 0.25%-of-point accuracy over a 50 to one range in flowrates. Three types were selected and were further analyzed to determine what problem areas prevented them from meeting the high accuracy requirement, and what the further development needs were for each. A dual-turbine volumetric flowmeter with densi-viscometer and microprocessor compensation was selected for its relative simplicity and fast response time. An angular momentum type with a motor-driven, spring-restrained turbine and viscosity shroud was selected for its direct mass-flow output. This concept also employed a turbine for fast response and a microcomputer for accurate viscosity compensation. The third concept employed a vortex precession volumetric flowmeter and was selected for its unobtrusive design. Like the turbine flowmeter, it uses a densi-viscometer and microprocessor for density correction and accurate viscosity compensation

Intense slow beams of bosonic potassium isotopes

We report on an experimental realization of a two-dimensional magneto-optical trap (2D-MOT) that allows the generation of cold atomic beams of 39K and 41K bosonic potassium isotopes. The high measured fluxes up to 1.0x10^11 atoms/s and low atomic velocities around 33 m/s are well suited for a fast and reliable 3D-MOT loading, a basilar feature for new generation experiments on Bose-Einstein condensation of dilute atomic samples. We also present a simple multilevel theoretical model for the calculation of the light-induced force acting on an atom moving in a MOT. The model gives a good agreement between predicted and measured flux and velocity values for our 2D-MOT.Comment: Updated references, 1 figure added, 10 pages, 9 figure

Ultracold molecules: vehicles to scalable quantum information processing

We describe a novel scheme to implement scalable quantum information processing using Li-Cs molecular state to entangle $^{6}$Li and $^{133}$Cs ultracold atoms held in independent optical lattices. The $^{6}$Li atoms will act as quantum bits to store information, and $^{133}$Cs atoms will serve as messenger bits that aid in quantum gate operations and mediate entanglement between distant qubit atoms. Each atomic species is held in a separate optical lattice and the atoms can be overlapped by translating the lattices with respect to each other. When the messenger and qubit atoms are overlapped, targeted single spin operations and entangling operations can be performed by coupling the atomic states to a molecular state with radio-frequency pulses. By controlling the frequency and duration of the radio-frequency pulses, entanglement can either be created or swapped between a qubit messenger pair. We estimate operation fidelities for entangling two distant qubits and discuss scalability of this scheme and constraints on the optical lattice lasers

Resolution enhancement of multichannel microwave imagery from the Nimbus-7 SMMR for maritime rainfall analysis

A restoration of the 37, 21, 18, 10.7, and 6.6 GHz satellite imagery from the scanning multichannel microwave radiometer (SMMR) aboard Nimbus-7 to 22.2 km resolution is attempted using a deconvolution method based upon nonlinear programming. The images are deconvolved with and without the aid of prescribed constraints, which force the processed image to abide by partial a priori knowledge of the high-resolution result. The restored microwave imagery may be utilized to examined the distribution of precipitating liquid water in marine rain systems

Piezoelectric devices for vibration suppression: Modeling and application to a truss structure

For a space structure assembled from truss members, an effective way to control the structure may be to replace the regular truss elements by active members. The active members play the role of load carrying elements as well as actuators. A piezo strut, made of a stack of piezoceramics, may be an ideal active member to be integrated into a truss space structure. An electrically driven piezo strut generates a pair of forces, and is considered as a two-point actuator in contrast to a one-point actuator such as a thruster or a shaker. To achieve good structural vibration control, sensing signals compatible to the control actuators are desirable. A strain gage or a piezo film with proper signal conditioning to measure member strain or strain rate, respectively, are ideal control sensors for use with a piezo actuator. The Phase 0 CSI Evolutionary Model (CEM) at NASA Langley Research Center used cold air thrusters as actuators to control both rigid body motions and flexible body vibrations. For the Phase 1 and 2 CEM, it is proposed to use piezo struts to control the flexible modes and thrusters to control the rigid body modes. A tenbay truss structure with active piezo struts is built to study the modeling, controller designs, and experimental issues. In this paper, the tenbay structure with piezo active members is modelled using an energy method approach. Decentralized and centralized control schemes are designed and implemented, and preliminary analytical and experimental results are presented