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Sample records for filters reduce amount

  1. Method for reducing pressure drop through filters, and filter exhibiting reduced pressure drop

    SciTech Connect

    Sappok, Alexander; Wong, Victor

    2014-11-18

    Methods for generating and applying coatings to filters with porous material in order to reduce large pressure drop increases as material accumulates in a filter, as well as the filter exhibiting reduced and/or more uniform pressure drop. The filter can be a diesel particulate trap for removing particulate matter such as soot from the exhaust of a diesel engine. Porous material such as ash is loaded on the surface of the substrate or filter walls, such as by coating, depositing, distributing or layering the porous material along the channel walls of the filter in an amount effective for minimizing or preventing depth filtration during use of the filter. Efficient filtration at acceptable flow rates is achieved.

  2. Cermet Filters To Reduce Diesel Engine Emissions

    SciTech Connect

    Kong, Peter

    2001-08-05

    Pollution from diesel engines is a significant part of our nation's air-quality problem. Even under the more stringent standards for heavy-duty engines set to take effect in 2004, these engines will continue to emit large amounts of nitrogen oxides and particulate matter, both of which affect public health. To address this problem, the Idaho National Engineering and Environmental Laboratory (INEEL) invented a self-cleaning, high temperature, cermet filter that reduces heavy-duty diesel engine emissions. The main advantage of the INEEL cermet filter, compared to current technology, is its ability to destroy carbon particles and NOx in diesel engine exhaust. As a result, this technology is expected to improve our nation's environmental quality by meeting the need for heavy-duty diesel engine emissions control. This paper describes the cermet filter technology and the initial research and development effort.Diesel engines currently emit soot and NOx that pollute our air. It is expected that the U.S. Environmental Protection Agency (EPA) will begin tightening the regulatory requirements to control these emissions. The INEEL's self-cleaning, high temperature cermet filter provides a technology to clean heavy-duty diesel engine emissions. Under high engine exhaust temperatures, the cermet filter simultaneously removes carbon particles and NOx from the exhaust gas. The cermet filter is made from inexpensive starting materials, via net shape bulk forming and a single-step combustion synthesis process, and can be brazed to existing structures. It is self-cleaning, lightweight, mechanically strong, thermal shock resistant, and has a high melting temperature, high heat capacity, and controllable thermal expansion coefficient. The filter's porosity is controlled to provide high removal efficiency for carbon particulate. It can be made catalytic to oxidize CO, H2, and hydrocarbons, and reduce NOx. When activated by engine exhaust, the filter produces NH3 and light hydrocarbon

  3. Reduced-Order Kalman Filtering for Processing Relative Measurements

    NASA Technical Reports Server (NTRS)

    Bayard, David S.

    2008-01-01

    A study in Kalman-filter theory has led to a method of processing relative measurements to estimate the current state of a physical system, using less computation than has previously been thought necessary. As used here, relative measurements signifies measurements that yield information on the relationship between a later and an earlier state of the system. An important example of relative measurements arises in computer vision: Information on relative motion is extracted by comparing images taken at two different times. Relative measurements do not directly fit into standard Kalman filter theory, in which measurements are restricted to those indicative of only the current state of the system. One approach heretofore followed in utilizing relative measurements in Kalman filtering, denoted state augmentation, involves augmenting the state of the system at the earlier of two time instants and then propagating the state to the later time instant.While state augmentation is conceptually simple, it can also be computationally prohibitive because it doubles the number of states in the Kalman filter. When processing a relative measurement, if one were to follow the state-augmentation approach as practiced heretofore, one would find it necessary to propagate the full augmented state Kalman filter from the earlier time to the later time and then select out the reduced-order components. The main result of the study reported here is proof of a property called reduced-order equivalence (ROE). The main consequence of ROE is that it is not necessary to augment with the full state, but, rather, only the portion of the state that is explicitly used in the partial relative measurement. In other words, it suffices to select the reduced-order components first and then propagate the partial augmented state Kalman filter from the earlier time to the later time; the amount of computation needed to do this can be substantially less than that needed for propagating the full augmented

  4. Reduced-order Kalman filtering with incomplete observability

    NASA Technical Reports Server (NTRS)

    Yonezawa, K.

    1980-01-01

    Kalman filtering is considered with reference to linear stochastic dynamic systems without complete observability. It is shown that the canonical decomposition theorem can be extended to the stochastic case and the matrix Riccati equation of the Kalman filter is order-reducible if some states are not observable. The inclusion of unobservable states in Kalman filtering makes the unobservable states 'asymptotically' observable in the filter if these unobservable states are dynamically connected to observable states and asymptotically stable. The reduced-order Kalman filter saves computation time when compared to the conventional Kalman filter.

  5. Electrically heated particulate filter with reduced stress

    DOEpatents

    Gonze, Eugene V.

    2013-03-05

    A system comprises a particulate matter (PM) filter comprising an inlet for receiving exhaust gas. A zoned heater is arranged in the inlet and comprises a resistive heater comprising N zones, where N is an integer greater than one. Each of the N zones comprises M sub-zones, where M is an integer greater than one. A control module selectively activates one of the N zones to initiate regeneration in downstream portions of the PM filter from the one of the N zones and deactivates others of the N zones.

  6. Reduced Kalman Filters for Clock Ensembles

    NASA Technical Reports Server (NTRS)

    Greenhall, Charles A.

    2011-01-01

    This paper summarizes the author's work ontimescales based on Kalman filters that act upon the clock comparisons. The natural Kalman timescale algorithm tends to optimize long-term timescale stability at the expense of short-term stability. By subjecting each post-measurement error covariance matrix to a non-transparent reduction operation, one obtains corrected clocks with improved short-term stability and little sacrifice of long-term stability.

  7. Speckle reducing bilateral filter for cattle follicle segmentation

    PubMed Central

    2010-01-01

    Background Ultrasound imaging technology has wide applications in cattle reproduction and has been used to monitor individual follicles and determine the patterns of follicular development. However, the speckles in ultrasound images affect the post-processing, such as follicle segmentation and finally affect the measurement of the follicles. In order to reduce the effect of speckles, a bilateral filter is developed in this paper. Results We develop a new bilateral filter for speckle reduction in ultrasound images for follicle segmentation and measurement. Different from the previous bilateral filters, the proposed bilateral filter uses normalized difference in the computation of the Gaussian intensity difference. We also present the results of follicle segmentation after speckle reduction. Experimental results on both synthetic images and real ultrasound images demonstrate the effectiveness of the proposed filter. Conclusions Compared with the previous bilateral filters, the proposed bilateral filter can reduce speckles in both high-intensity regions and low intensity regions in ultrasound images. The segmentation of the follicles in the speckle reduced images by the proposed method has higher performance than the segmentation in the original ultrasound image, and the images filtered by Gaussian filter, the conventional bilateral filter respectively. PMID:21047390

  8. Distributed Particle Filter for Target Tracking: With Reduced Sensor Communications.

    PubMed

    Ghirmai, Tadesse

    2016-01-01

    For efficient and accurate estimation of the location of objects, a network of sensors can be used to detect and track targets in a distributed manner. In nonlinear and/or non-Gaussian dynamic models, distributed particle filtering methods are commonly applied to develop target tracking algorithms. An important consideration in developing a distributed particle filtering algorithm in wireless sensor networks is reducing the size of data exchanged among the sensors because of power and bandwidth constraints. In this paper, we propose a distributed particle filtering algorithm with the objective of reducing the overhead data that is communicated among the sensors. In our algorithm, the sensors exchange information to collaboratively compute the global likelihood function that encompasses the contribution of the measurements towards building the global posterior density of the unknown location parameters. Each sensor, using its own measurement, computes its local likelihood function and approximates it using a Gaussian function. The sensors then propagate only the mean and the covariance of their approximated likelihood functions to other sensors, reducing the communication overhead. The global likelihood function is computed collaboratively from the parameters of the local likelihood functions using an average consensus filter or a forward-backward propagation information exchange strategy. PMID:27618057

  9. Using Kalman filters to reduce noise from RFID location system.

    PubMed

    Abreu, Pedro Henriques; Xavier, José; Silva, Daniel Castro; Reis, Luís Paulo; Petry, Marcelo

    2014-01-01

    Nowadays, there are many technologies that support location systems involving intrusive and nonintrusive equipment and also varying in terms of precision, range, and cost. However, the developers some time neglect the noise introduced by these systems, which prevents these systems from reaching their full potential. Focused on this problem, in this research work a comparison study between three different filters was performed in order to reduce the noise introduced by a location system based on RFID UWB technology with an associated error of approximately 18 cm. To achieve this goal, a set of experiments was devised and executed using a miniature train moving at constant velocity in a scenario with two distinct shapes-linear and oval. Also, this train was equipped with a varying number of active tags. The obtained results proved that the Kalman Filter achieved better results when compared to the other two filters. Also, this filter increases the performance of the location system by 15% and 12% for the linear and oval paths respectively, when using one tag. For a multiple tags and oval shape similar results were obtained (11-13% of improvement). PMID:24592186

  10. Using Kalman Filters to Reduce Noise from RFID Location System

    PubMed Central

    Xavier, José; Reis, Luís Paulo; Petry, Marcelo

    2014-01-01

    Nowadays, there are many technologies that support location systems involving intrusive and nonintrusive equipment and also varying in terms of precision, range, and cost. However, the developers some time neglect the noise introduced by these systems, which prevents these systems from reaching their full potential. Focused on this problem, in this research work a comparison study between three different filters was performed in order to reduce the noise introduced by a location system based on RFID UWB technology with an associated error of approximately 18 cm. To achieve this goal, a set of experiments was devised and executed using a miniature train moving at constant velocity in a scenario with two distinct shapes—linear and oval. Also, this train was equipped with a varying number of active tags. The obtained results proved that the Kalman Filter achieved better results when compared to the other two filters. Also, this filter increases the performance of the location system by 15% and 12% for the linear and oval paths respectively, when using one tag. For a multiple tags and oval shape similar results were obtained (11–13% of improvement). PMID:24592186

  11. Reduced-Rank Adaptive Filtering Using Krylov Subspace

    NASA Astrophysics Data System (ADS)

    Burykh, Sergueï; Abed-Meraim, Karim

    2003-12-01

    A unified view of several recently introduced reduced-rank adaptive filters is presented. As all considered methods use Krylov subspace for rank reduction, the approach taken in this work is inspired from Krylov subspace methods for iterative solutions of linear systems. The alternative interpretation so obtained is used to study the properties of each considered technique and to relate one reduced-rank method to another as well as to algorithms used in computational linear algebra. Practical issues are discussed and low-complexity versions are also included in our study. It is believed that the insight developed in this paper can be further used to improve existing reduced-rank methods according to known results in the domain of Krylov subspace methods.

  12. Use of Grating in Reading Multilayer Discs to Reduce Amount of Interlayer Crosstalk

    NASA Astrophysics Data System (ADS)

    Kimura, Shigeharu; Ide, Tatsuro; Anzai, Yumiko; Watanabe, Koichi; Shintani, Toshimichi; Tatsu, Eriko

    2009-03-01

    Crosstalk from adjacent layers affects the tracking error signal of conventional optical pickups when a multilayered disc is read. The tracking error signal fluctuates and makes precise tracking difficult. We propose the use of a grating in the return path to reduce the amount of crosstalk. Using a grating with an uneven plane on the optical axis reduces the amount of stray light causing the crosstalk and allows the target light to pass through. We show that using a grating with an appropriate pitch prevents diffracted light higher than an order of ±1 from going back to detectors. As the shape and depth of the grating are important factors for the zeroth-order light, we chose a deep triangular grating. We measured the distribution of the transmitted intensity through the grating as a focused beam position was scanned and found that the grating can reduce the amount of crosstalk.

  13. Wavelet Filtering to Reduce Conservatism in Aeroservoelastic Robust Stability Margins

    NASA Technical Reports Server (NTRS)

    Brenner, Marty; Lind, Rick

    1998-01-01

    Wavelet analysis for filtering and system identification was used to improve the estimation of aeroservoelastic stability margins. The conservatism of the robust stability margins was reduced with parametric and nonparametric time-frequency analysis of flight data in the model validation process. Nonparametric wavelet processing of data was used to reduce the effects of external desirableness and unmodeled dynamics. Parametric estimates of modal stability were also extracted using the wavelet transform. Computation of robust stability margins for stability boundary prediction depends on uncertainty descriptions derived from the data for model validation. F-18 high Alpha Research Vehicle aeroservoelastic flight test data demonstrated improved robust stability prediction by extension of the stability boundary beyond the flight regime.

  14. C. elegans miro-1 Mutation Reduces the Amount of Mitochondria and Extends Life Span

    PubMed Central

    Shen, Yanqing; Ng, Li Fang; Low, Natarie Pei Wen; Hagen, Thilo; Gruber, Jan; Inoue, Takao

    2016-01-01

    Mitochondria play a critical role in aging, however, the underlying mechanism is not well understood. We found that a mutation disrupting the C. elegans homolog of Miro GTPase (miro-1) extends life span. This phenotype requires simultaneous loss of miro-1 from multiple tissues including muscles and neurons, and is dependent on daf-16/FOXO. Notably, the amount of mitochondria in the miro-1 mutant is reduced to approximately 50% of the wild-type. Despite this reduction, oxygen consumption is only weakly reduced, suggesting that mitochondria of miro-1 mutants are more active than wild-type mitochondria. The ROS damage is slightly reduced and the mitochondrial unfolded protein response pathway is weakly activated in miro-1 mutants. Unlike previously described long-lived mitochondrial electron transport chain mutants, miro-1 mutants have normal growth rate. These results suggest that the reduction in the amount of mitochondria can affect the life span of an organism through activation of stress pathways. PMID:27064409

  15. C. elegans miro-1 Mutation Reduces the Amount of Mitochondria and Extends Life Span.

    PubMed

    Shen, Yanqing; Ng, Li Fang; Low, Natarie Pei Wen; Hagen, Thilo; Gruber, Jan; Inoue, Takao

    2016-01-01

    Mitochondria play a critical role in aging, however, the underlying mechanism is not well understood. We found that a mutation disrupting the C. elegans homolog of Miro GTPase (miro-1) extends life span. This phenotype requires simultaneous loss of miro-1 from multiple tissues including muscles and neurons, and is dependent on daf-16/FOXO. Notably, the amount of mitochondria in the miro-1 mutant is reduced to approximately 50% of the wild-type. Despite this reduction, oxygen consumption is only weakly reduced, suggesting that mitochondria of miro-1 mutants are more active than wild-type mitochondria. The ROS damage is slightly reduced and the mitochondrial unfolded protein response pathway is weakly activated in miro-1 mutants. Unlike previously described long-lived mitochondrial electron transport chain mutants, miro-1 mutants have normal growth rate. These results suggest that the reduction in the amount of mitochondria can affect the life span of an organism through activation of stress pathways. PMID:27064409

  16. Two Reduced Resolution Filter Approaches to Data Assimilation

    NASA Technical Reports Server (NTRS)

    Todling, Ricardo; Cohn, Stephen E.

    1996-01-01

    In this paper we evaluate the performance of two reduced resolution filter approaches to data assimilation. The main distinction between these approaches is in the manner they propagate error covariances. Both account for error covariances in a space with dimension m smaller than the model's state vector dimension n. In the first approach the m dimensional error covariance matrix is interpolated to the n-dimensional space and propagated with the n-dimensional dynamics. In the second approach the low-dimensional error covariance matrix is propagated by a dynamical operator generated in the m-dimensional space. Our experiments indicate that the first approach provides a more reliable simplified scheme for error covariance propagation than the second approach.

  17. Engineering Filters for Reducing Spontaneous Emission in cQED

    NASA Astrophysics Data System (ADS)

    Bronn, Nicholas; Masluk, Nicholas; Srinivasan, Srikanth; Chow, Jerry; Abraham, David; Rothwell, Mary; Keefe, George; Gambetta, Jay; Steffen, Matthias; Lirakis, Chris

    2014-03-01

    Inserting a notch filter between a qubit and the external environment at the qubit frequency can significantly suppress spontaneous emission mediated by the cavity (``Purcell effect''). In order to realize this filtering in multi-qubit architectures, where space comes at a premium, we will present a filter with minimal space requirements. We acknowledge support from IARPA under contract W911NF-10-1-0324.

  18. Recent Progress with Atmospheric Noise-Reducing Filters

    NASA Astrophysics Data System (ADS)

    Hedlin, M. A.

    2003-12-01

    Wind noise is one of the key issues facing the community of acousticians who monitor the atmosphere for long-period signals from natural atmospheric phenomena or from man-made sources, such as nuclear weapons tests. Presently, a network of infrasound observing sites is being constructed to provide global coverage of acoustic sources in the atmosphere. It is well known that spatial filters can be used to attenuate noise due to atmospheric turbulence near the recording point and increase the ratio of signal-to-noise. Rosette spatial filters are currently used at the new infrasound monitoring stations and have been found to provide a significant reduction of noise across the frequency band of interest to the acoustic monitoring community. Research continues into modifications to existing rosette filters that might improve their performance. Additional research is providing insight into entirely different filters, such as wind barriers. Some of the monitoring system's array sites are located on oceanic islands at locations where spatially extensive noise filters will not be practical. This practical limitation fuels our interest in effective, spatially compact filtering methods. This presentation gives an overview of the various filters currently being used and research into improvements for these filters and into entirely different filter designs.

  19. Recent progress with atmospheric noise-reducing filters

    NASA Astrophysics Data System (ADS)

    Hedlin, Michael

    2003-04-01

    Wind noise is one of the key issues facing the community of acousticians who monitor the atmosphere for long-period signals from natural atmospheric phenomena or from man-made sources, such as nuclear weapons tests. Presently, a network of infrasound observing sites is being constructed to provide global coverage of acoustic sources in the atmosphere. It is well known that spatial filters can be used to attenuate noise due to atmospheric turbulence near the recording point and increase the ratio of signal-to-noise. Rosette spatial filters are currently used at the new infrasound monitoring stations and have been found to provide a significant reduction of noise across the frequency band of interest to the acoustic monitoring community. Research continues into modifications to existing rosette filters that might improve their performance. Additional research is providing insight into entirely different filters, such as wind barriers. Some of the monitoring systems array sites are located on oceanic islands at locations where spatially extensive noise filters will not be practical. This practical limitation fuels our interest in effective, spatially compact filtering methods. This presentation gives an overview of the various filters currently being used and research into improvements for these filters and into entirely different filter designs.

  20. Kinetic control by limiting glutaredoxin amounts enables thiol oxidation in the reducing mitochondrial intermembrane space

    PubMed Central

    Kojer, Kerstin; Peleh, Valentina; Calabrese, Gaetano; Herrmann, Johannes M.; Riemer, Jan

    2015-01-01

    The mitochondrial intermembrane space (IMS) harbors an oxidizing machinery that drives import and folding of small cysteine-containing proteins without targeting signals. The main component of this pathway is the oxidoreductase Mia40, which introduces disulfides into its substrates. We recently showed that the IMS glutathione pool is maintained as reducing as that of the cytosol. It thus remained unclear how equilibration of protein disulfides with the IMS glutathione pool is prevented in order to allow oxidation-driven protein import. Here we demonstrate the presence of glutaredoxins in the IMS and show that limiting amounts of these glutaredoxins provide a kinetic barrier to prevent the thermodynamically feasible reduction of Mia40 substrates by the IMS glutathione pool. Moreover, they allow Mia40 to exist in a predominantly oxidized state. Consequently, overexpression of glutaredoxin 2 in the IMS results in a more reduced Mia40 redox state and a delay in oxidative folding and mitochondrial import of different Mia40 substrates. Our findings thus indicate that carefully balanced glutaredoxin amounts in the IMS ensure efficient oxidative folding in the reducing environment of this compartment. PMID:25392302

  1. 45 CFR 261.51 - Under what circumstances will we reduce the amount of the penalty below the maximum?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false Under what circumstances will we reduce the amount of the penalty below the maximum? 261.51 Section 261.51 Public Welfare Regulations Relating to Public... to Work Requirements? § 261.51 Under what circumstances will we reduce the amount of the...

  2. 43 CFR 3809.591 - What are the limitations on the amount by which BLM may reduce my financial guarantee?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Financial Guarantee § 3809.591 What are the limitations on the amount by which BLM may reduce my financial... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false What are the limitations on the amount by which BLM may reduce my financial guarantee? 3809.591 Section 3809.591 Public Lands:...

  3. 43 CFR 3809.591 - What are the limitations on the amount by which BLM may reduce my financial guarantee?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Financial Guarantee § 3809.591 What are the limitations on the amount by which BLM may reduce my financial... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false What are the limitations on the amount by which BLM may reduce my financial guarantee? 3809.591 Section 3809.591 Public Lands:...

  4. 43 CFR 3809.591 - What are the limitations on the amount by which BLM may reduce my financial guarantee?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Financial Guarantee § 3809.591 What are the limitations on the amount by which BLM may reduce my financial... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false What are the limitations on the amount by which BLM may reduce my financial guarantee? 3809.591 Section 3809.591 Public Lands:...

  5. 43 CFR 3809.591 - What are the limitations on the amount by which BLM may reduce my financial guarantee?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Financial Guarantee § 3809.591 What are the limitations on the amount by which BLM may reduce my financial... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false What are the limitations on the amount by which BLM may reduce my financial guarantee? 3809.591 Section 3809.591 Public Lands:...

  6. A Reduced Dimension Static, Linearized Kalman Filter and Smoother

    NASA Technical Reports Server (NTRS)

    Fukumori, I.

    1995-01-01

    An approximate Kalman filter and smoother, based on approximations of the state estimation error covariance matrix, is described. Approximations include a reduction of the effective state dimension, use of a static asymptotic error limit, and a time-invariant linearization of the dynamic model for error integration. The approximations lead to dramatic computational savings in applying estimation theory to large complex systems. Examples of use come from TOPEX/POSEIDON.

  7. Effects of using passive filter for reduce electrical load harmonics

    NASA Astrophysics Data System (ADS)

    Sucita, T.

    2016-04-01

    Due to the use of electrical current load that uses a lot of electronic components (passive non-linear electrical loads), so the impact will cause harmonics in the electrical network system. These harmonics can unwittingly cause a relatively large loss in electrical energy consumption and can lower the power factor of an electrical installation. Limits how much the harmonic distortion that is installed on the load adjusted to the IEEE 519-1992 standard. The study was conducted by taking data on a network of electrical installation of a building using measuring devices Fluke 43B Power Quality Analyser. The data is then processed and consulted with the standard IEEE 519-1992. Once the data has a discrepancy with the standard, further made the filter design using linear passive components. The design is then installed on the network installation by means of simulated order harmonic losses can be overcome so that the circuit meets the IEEE standard installation by changing the parameters of the linear load L and C. The results of this study indicate that THDi value decreased after the installation of filters for phase R fell by 9.39%, the S phase decreased by 7.54% and for the T phase decreased by 16.88%. So that meets the IEEE standard by 15%.

  8. Carbohydrate-binding modules (CBMs) revisited: reduced amount of water counterbalances the need for CBMs

    PubMed Central

    2013-01-01

    Background A vast number of organisms are known to produce structurally diversified cellulases capable of degrading cellulose, the most abundant biopolymer on earth. The generally accepted paradigm is that the carbohydrate-binding modules (CBMs) of cellulases are required for efficient saccharification of insoluble substrates. Based on sequence data, surprisingly more than 60% of the cellulases identified lack carbohydrate-binding modules or alternative protein structures linked to cellulases (dockerins). This finding poses the question about the role of the CBMs: why would most cellulases lack CBMs, if they are necessary for the efficient hydrolysis of cellulose? Results The advantage of CBMs, which increase the affinity of cellulases to substrates, was found to be diminished by reducing the amount of water in the hydrolytic system, which increases the probability of enzyme-substrate interaction. At low substrate concentration (1% w/w), CBMs were found to be more important in the catalytic performance of the cellobiohydrolases TrCel7A and TrCel6A of Trichoderma reesei as compared to that of the endoglucanases TrCel5A and TrCel7B. Increasing the substrate concentration while maintaining the enzyme-to-substrate ratio enhanced adsorption of TrCel7A, independent of the presence of the CBM. At 20% (w/w) substrate concentration, the hydrolytic performance of cellulases without CBMs caught up with that of cellulases with CBMs. This phenomenon was more noticeable on the lignin-containing pretreated wheat straw as compared to the cellulosic Avicel, presumably due to unproductive adsorption of enzymes to lignin. Conclusions Here we propose that the water content in the natural environments of carbohydrate-degrading organisms might have led to the evolution of various substrate-binding structures. In addition, some well recognized problems of economical saccharification such as unproductive binding of cellulases, which reduces the hydrolysis rate and prevents recycling of

  9. Effectiveness of cigarette filter tips for reducing cadmium in relation to other mainstream smoke constituents

    SciTech Connect

    Bache, C.A.; Lisk, D.J.; Shane, B.S.; Hoffmann, D.; Adams, J.D.

    1987-01-01

    The effectiveness of filter tips for reducing cadmium, tar, nicotine, carbon monoxide and carbon dioxide in cigarettes was studied. The cigarettes were made from tobacco grown on municipal sewage sludge-amended soil and were therefore high in cadmium. When machine-smoked, filter tips did not result in a significant reduction of cadmium deposited on Cambridge filters. This may indicate that a considerable fraction of cadmium is present in the vapor phase of the smoke and therefore not reduced to the same extent as the tar by certain filters. Nicotine and carbon monoxide were reduced to a lesser extent than tar. This indicates that the filter tip has influenced the combustion of the tobacco column during smoking.

  10. 42 CFR 137.87 - May the Secretary reduce the amount of funds due under Title V in subsequent years?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SELF-GOVERNANCE Funding Prohibitions § 137.87 May the Secretary reduce the amount of funds due under... the terms of the funding agreement; or (e) Completion of a project, activity, or program for...

  11. 42 CFR 137.87 - May the Secretary reduce the amount of funds due under Title V in subsequent years?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SELF-GOVERNANCE Funding Prohibitions § 137.87 May the Secretary reduce the amount of funds due under... the terms of the funding agreement; or (e) Completion of a project, activity, or program for...

  12. 42 CFR 137.87 - May the Secretary reduce the amount of funds due under Title V in subsequent years?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SELF-GOVERNANCE Funding Prohibitions § 137.87 May the Secretary reduce the amount of funds due under... the terms of the funding agreement; or (e) Completion of a project, activity, or program for...

  13. 42 CFR 137.87 - May the Secretary reduce the amount of funds due under Title V in subsequent years?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SELF-GOVERNANCE Funding Prohibitions § 137.87 May the Secretary reduce the amount of funds due under... the terms of the funding agreement; or (e) Completion of a project, activity, or program for...

  14. 42 CFR 137.87 - May the Secretary reduce the amount of funds due under Title V in subsequent years?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SELF-GOVERNANCE Funding Prohibitions § 137.87 May the Secretary reduce the amount of funds due under... the terms of the funding agreement; or (e) Completion of a project, activity, or program for...

  15. Reduced-order filtering for flexible space structures

    NASA Technical Reports Server (NTRS)

    Sims, Craig S.

    1990-01-01

    There is a need for feedback control of the large flexible space structures which are going to be increasingly important in the future of the space program. These structures are very lightly damped, and vibrations may persist for a long time when the system is disturbed unless an active feedback control strategy is used to damp out the vibrations. The system is best described by a partial differential equation description, but the more common approach is to use a large set of second order differential equations, where a large number of modes must be retained if the mathematics is to provide an adequate description of the dynamical process. Sensors, such as accelerometers and rate gyros, may provide data to the feedback controller so that it may respond appropriately to control the system. The data from the sensors is not perfect, but is subject to noise, called measurement noise, and the dynamical process itself is subject to disturbances referred to as process noise. Filtering the sensor signals to remove the measurement noise, and using the resulting state estimates to control the system are investigated.

  16. Efficiency of automotive cabin air filters to reduce acute health effects of diesel exhaust in human subjects

    PubMed Central

    Rudell, B.; Wass, U.; Horstedt, P.; Levin, J. O.; Lindahl, R.; Rannug, U.; Sunesson, A. L.; Ostberg, Y.; Sandstrom, T.

    1999-01-01

    OBJECTIVES: To evaluate the efficiency of different automotive cabin air filters to prevent penetration of components of diesel exhaust and thereby reduce biomedical effects in human subjects. Filtered air and unfiltered diluted diesel exhaust (DDE) were used as negative and positive controls, respectively, and were compared with exposure to DDE filtered with four different filter systems. METHODS: 32 Healthy non- smoking subjects (age 21-53) participated in the study. Each subject was exposed six times for 1 hour in a specially designed exposure chamber: once to air, once to unfiltered DDE, and once to DDE filtered with the four different cabin air filters. Particle concentrations during exposure to unfiltered DDE were kept at 300 micrograms/m3. Two of the filters were particle filters. The other two were particle filters combined with active charcoal filters that might reduce certain gaseous components. Subjective symptoms were recorded and nasal airway lavage (NAL), acoustic rhinometry, and lung function measurements were performed. RESULTS: The two particle filters decreased the concentrations of diesel exhaust particles by about half, but did not reduce the intensity of symptoms induced by exhaust. The combination of active charcoal filters and a particle filter significantly reduced the symptoms and discomfort caused by the diesel exhaust. The most noticable differences in efficacy between the filters were found in the reduction of detection of an unpleasant smell from the diesel exhaust. In this respect even the two charcoal filter combinations differed significantly. The efficacy to reduce symptoms may depend on the abilities of the filters investigated to reduce certain hydrocarbons. No acute effects on NAL, rhinometry, and lung function variables were found. CONCLUSIONS: This study has shown that the use of active charcoal filters, and a particle filter, clearly reduced the intensity of symptoms induced by diesel exhaust. Complementary studies on vehicle

  17. 45 CFR 261.51 - Under what circumstances will we reduce the amount of the penalty below the maximum?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 2 2014-10-01 2012-10-01 true Under what circumstances will we reduce the amount of the penalty below the maximum? 261.51 Section 261.51 Public Welfare Regulations Relating to Public Welfare OFFICE OF FAMILY ASSISTANCE (ASSISTANCE PROGRAMS), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN...

  18. 45 CFR 261.55 - Under what circumstances will we reduce the amount of the penalty for not properly imposing...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 2 2010-10-01 2010-10-01 false Under what circumstances will we reduce the amount of the penalty for not properly imposing penalties on individuals? 261.55 Section 261.55 Public Welfare Regulations Relating to Public Welfare OFFICE OF FAMILY ASSISTANCE (ASSISTANCE PROGRAMS), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT...

  19. 45 CFR 261.55 - Under what circumstances will we reduce the amount of the penalty for not properly imposing...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 2 2014-10-01 2012-10-01 true Under what circumstances will we reduce the amount of the penalty for not properly imposing penalties on individuals? 261.55 Section 261.55 Public Welfare Regulations Relating to Public Welfare OFFICE OF FAMILY ASSISTANCE (ASSISTANCE PROGRAMS), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT...

  20. Waste water treatment costs reduced by 50% with rotary vacuum precoat filter

    SciTech Connect

    Mrozinski, W.; Short, A.J.

    1983-01-01

    This article describes a rotary vacuum precoat filter which reduces waste treatment costs by 50%. This filter was used to solve Union Carbide Corporation's Linde Division's plant problem of high operating costs at the facility due to frequent cleaning, repair, and replacement of electric filters.The solids separation system at Linde's waste water treatment facility also had high operating, maintenance and sludge disposal costs. Installation of the rotary vacuum precoat filter with diatomite precoat performs the same functions as were previously accomplished with the high pressure filter and a centrifuge, and does these with less total horsepower, fewer water treatment chemicals, reduced maintenance, and lower water content in the sludge. All of these improvements have added up to a 50% reduction in the total cost of waste water treatment. On a trial-basis, the small rotary vacuum precoat flter satisfactorily handled all the waste water treatment required at present plant production rates. Based on full plant operating rates and the installation of an appropriate sized filter, total savings from using this system are estimated at $92,000/yr.

  1. Grapevine downy mildew control using reduced copper amounts in organic viticulture.

    PubMed

    La Torre, A; Pompi, V; Mandalà, C; Cioffi, C

    2011-01-01

    Copper is an essential natural micronutrient. However, copper used as a plant protection product may have long-term consequences due to its accumulation in the soil. Limitations on copper use have therefore been defined in organic farming (Regulation EC 889/2008). In the light of new developments and evidence, the European Commission has planned to assess whether further restrictions are needed in the quantities of copper permitted. A two-year field trial was therefore set up with new copper formulations to evaluate the possibility of reducing the copper quantities applied with treatments and consequently to reduce copper soil residues. Plots were prepared, each containing 12 plants and repeated four times in randomized blocks. The test organism was Plasmopara viticola (Berk. and M.A. Curtis) Berl. and De Toni. Cupric formulations characterised by a low metallic content (Glutex CU 90 and Labicuper) were tested in comparison with a reference product (standard) and an untreated control. Evaluations of treatments were carried out periodically on 100 leaves and 100 bunches for each replicate. Data obtained were subjected to statistical analysis. Chemical analyses were performed to determine copper residues on leaves, grapes and soil. Samplings of leaves and grapes were carried out for each replicate. Soil samples were taken from 0-20 cm and 20-40 cm depth. Total copper was determined using spectrophotometry in atomic absorption by acetylene-air flame (FAAS at lambda = 324.8 microm). The results showed that the tested products were effective in controlling downy mildew with a lower copper dosage than with the cupric formulations used as a standard. Glutex CU 90 formulation led to an annual input of copper that was a little more than a third compared to the standard and Labicuper about a fifth or a sixth. At harvest, copper levels in grapes were much lower than RML (fixed at 50 mg/kg). With regard to the impact of cupric treatments on organic vineyard soil, no

  2. A Computationally Efficient Filter for Reducing Shot Noise in Low S/N Data

    PubMed Central

    Okada, Mami; Ishikawa, Tomoe; Ikegaya, Yuji

    2016-01-01

    Functional multineuron calcium imaging (fMCI) provides a useful experimental platform to simultaneously capture the spatiotemporal patterns of neuronal activity from a large cell population in situ. However, fMCI often suffers from low signal-to-noise ratios (S/N). The main factor that causes the low S/N is shot noise that arises from photon detectors. Here, we propose a new denoising procedure, termed the Okada filter, which is designed to reduce shot noise under low S/N conditions, such as fMCI. The core idea of the Okada filter is to replace the fluorescence intensity value of a given frame time with the average of two values at the preceding and following frames unless the focused value is the median among these three values. This process is iterated serially throughout a time-series vector. In fMCI data of hippocampal neurons, the Okada filter rapidly reduces background noise and significantly improves the S/N. The Okada filter is also applicable for reducing shot noise in electrophysiological data and photographs. Finally, the Okada filter can be described using a single continuous differentiable equation based on the logistic function and is thus mathematically tractable. PMID:27304217

  3. White-tailed deer are a biotic filter during community assembly, reducing species and phylogenetic diversity

    PubMed Central

    Begley-Miller, Danielle R.; Hipp, Andrew L.; Brown, Bethany H.; Hahn, Marlene; Rooney, Thomas P.

    2014-01-01

    Community assembly entails a filtering process, where species found in a local community are those that can pass through environmental (abiotic) and biotic filters and successfully compete. Previous research has demonstrated the ability of white-tailed deer (Odocoileus virginianus) to reduce species diversity and favour browse-tolerant plant communities. In this study, we expand on our previous work by investigating deer as a possible biotic filter altering local plant community assembly. We used replicated 23-year-old deer exclosures to experimentally assess the effects of deer on species diversity (H′), richness (SR), phylogenetic community structure and phylogenetic diversity in paired browsed (control) and unbrowsed (exclosed) plots. Additionally, we developed a deer-browsing susceptibility index (DBSI) to assess the vulnerability of local species to deer. Deer browsing caused a 12 % reduction in H′ and 17 % reduction in SR, consistent with previous studies. Furthermore, browsing reduced phylogenetic diversity by 63 %, causing significant phylogenetic clustering. Overall, graminoids were the least vulnerable to deer browsing based on DBSI calculations. These findings demonstrate that deer are a significant driver of plant community assembly due to their role as a selective browser, or more generally, as a biotic filter. This study highlights the importance of knowledge about the plant tree of life in assessing the effects of biotic filters on plant communities. Application of such knowledge has considerable potential to advance our understanding of plant community assembly. PMID:24916059

  4. Trans-resveratrol and beta-carotene from sunscreens penetrate viable skin layers and reduce cutaneous penetration of UV-filters.

    PubMed

    Freitas, J V; Praça, F S G; Bentley, M V L B; Gaspar, L R

    2015-04-30

    Cutaneous permeation is a critical parameter when topical application of sunscreens containing antioxidants is considered. The aim of this study was to evaluate the cutaneous penetration of most marketed UV-filters combined with trans-resveratrol (RES) and beta-carotene (BTC) since few studies report skin penetration when such compounds are applied. Formulations containing octocrylene, octyl methoxycinnamate, avobenzone and bemotrizinole were prepared and supplemented or not with BTC, or with RES, or with both compounds in combination. Penetration studies were performed using Franz vertical diffusion cells and porcine ear skin as the biological membrane. The quantification of UV-filters and antioxidants in the stratum corneum (SC), viable epidermis plus dermis and receptor fluid was performed by HPLC. Results suggested that UV-filters and antioxidants did not permeate the skin but were retained for 12h post application. About 90% and 80%, respectively, of the total penetrated amount of UV-filters and antioxidants was found in the SC. Interestingly, it was observed that BTC, alone or combined with RES, reduced the skin retention of UV-filters on average by 63%. In conclusion, this study demonstrated that the combination of antioxidants and UV-filters in sunscreens is advantageous for cutaneous penetration, since BTC and BTC+RES improved sunscreen safety by reducing delivery of the four UV-filters in the study into SC and viable epidermis. PMID:25724133

  5. Assimilating irregularly spaced sparsely observed turbulent signals with hierarchical Bayesian reduced stochastic filters

    SciTech Connect

    Brown, Kristen A.; Harlim, John

    2013-02-15

    In this paper, we consider a practical filtering approach for assimilating irregularly spaced, sparsely observed turbulent signals through a hierarchical Bayesian reduced stochastic filtering framework. The proposed hierarchical Bayesian approach consists of two steps, blending a data-driven interpolation scheme and the Mean Stochastic Model (MSM) filter. We examine the potential of using the deterministic piecewise linear interpolation scheme and the ordinary kriging scheme in interpolating irregularly spaced raw data to regularly spaced processed data and the importance of dynamical constraint (through MSM) in filtering the processed data on a numerically stiff state estimation problem. In particular, we test this approach on a two-layer quasi-geostrophic model in a two-dimensional domain with a small radius of deformation to mimic ocean turbulence. Our numerical results suggest that the dynamical constraint becomes important when the observation noise variance is large. Second, we find that the filtered estimates with ordinary kriging are superior to those with linear interpolation when observation networks are not too sparse; such robust results are found from numerical simulations with many randomly simulated irregularly spaced observation networks, various observation time intervals, and observation error variances. Third, when the observation network is very sparse, we find that both the kriging and linear interpolations are comparable.

  6. Assimilating irregularly spaced sparsely observed turbulent signals with hierarchical Bayesian reduced stochastic filters

    NASA Astrophysics Data System (ADS)

    Brown, Kristen A.; Harlim, John

    2013-02-01

    In this paper, we consider a practical filtering approach for assimilating irregularly spaced, sparsely observed turbulent signals through a hierarchical Bayesian reduced stochastic filtering framework. The proposed hierarchical Bayesian approach consists of two steps, blending a data-driven interpolation scheme and the Mean Stochastic Model (MSM) filter. We examine the potential of using the deterministic piecewise linear interpolation scheme and the ordinary kriging scheme in interpolating irregularly spaced raw data to regularly spaced processed data and the importance of dynamical constraint (through MSM) in filtering the processed data on a numerically stiff state estimation problem. In particular, we test this approach on a two-layer quasi-geostrophic model in a two-dimensional domain with a small radius of deformation to mimic ocean turbulence. Our numerical results suggest that the dynamical constraint becomes important when the observation noise variance is large. Second, we find that the filtered estimates with ordinary kriging are superior to those with linear interpolation when observation networks are not too sparse; such robust results are found from numerical simulations with many randomly simulated irregularly spaced observation networks, various observation time intervals, and observation error variances. Third, when the observation network is very sparse, we find that both the kriging and linear interpolations are comparable.

  7. Reducing the complexity of the CCSDS standard for image compression decreasing the DWT filter order

    NASA Astrophysics Data System (ADS)

    Ito, Leandro H.; Pinho, Marcelo S.

    2014-10-01

    The goal for this work is to evaluate the impact of utilizing shorter wavelet filters in the CCSDS standard for lossy and lossless image compression. Another constraint considered was the existence of symmetry in the filters. That approach was desired to maintain the symmetric extension compatibility of the filter banks. Even though this strategy works well for oat wavelets, it is not always the case for their integer approximations. The periodic extension was utilized whenever symmetric extension was not applicable. Even though the latter outperforms the former, for fair comparison the symmetric extension compatible integer-to-integer wavelet approximations were evaluated under both extensions. The evaluation methods adopted were bit rate (bpp), PSNR and the number of operations required by each wavelet transforms. All these results were compared against the ones obtained utilizing the standard CCSDS with 9/7 filter banks, for lossy and lossless compression. The tests were performed over tallies (512x512) of raw remote sensing images from CBERS-2B (China-Brazil Earth Resources Satellites) captured from its high resolution CCD camera. These images were cordially made available by INPE (National Institute for Space Research) in Brazil. For the CCSDS implementation, it was utilized the source code developed by Hongqiang Wang from the Electrical Department at Nebraska-Lincoln University, applying the appropriate changes on the wavelet transform. For lossy compression, the results have shown that the filter bank built from the Deslauriers-Dubuc scaling function, with respectively 2 and 4 vanishing moments on the synthesis and analysis banks, presented not only a reduction of 21% in the number of operations required, but also a performance on par with the 9/7 filter bank. In the lossless case, the biorthogonal Cohen-Daubechies-Feauveau with 2 vanishing moments presented a performance close to the 9/7 integer approximation of the CCSDS, with the number of operations

  8. HEPA air filter (image)

    MedlinePlus

    ... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

  9. A comb filter based signal processing method to effectively reduce motion artifacts from photoplethysmographic signals.

    PubMed

    Peng, Fulai; Liu, Hongyun; Wang, Weidong

    2015-10-01

    A photoplethysmographic (PPG) signal can provide very useful information about a subject's cardiovascular status. Motion artifacts (MAs), which usually deteriorate the waveform of a PPG signal, severely obstruct its applications in the clinical diagnosis and healthcare area. To reduce the MAs from a PPG signal, in the present study we present a comb filter based signal processing method. Firstly, wavelet de-noising was implemented to preliminarily suppress a part of the MAs. Then, the PPG signal in the time domain was transformed into the frequency domain by a fast Fourier transform (FFT). Thirdly, the PPG signal period was estimated from the frequency domain by tracking the fundamental frequency peak of the PPG signal. Lastly, the MAs were removed by the comb filter which was designed based on the obtained PPG signal period. Experiments with synthetic and real-world datasets were implemented to validate the performance of the method. Results show that the proposed method can effectively restore the PPG signals from the MA corrupted signals. Also, the accuracy of blood oxygen saturation (SpO2), calculated from red and infrared PPG signals, was significantly improved after the MA reduction by the proposed method. Our study demonstrates that the comb filter can effectively reduce the MAs from a PPG signal provided that the PPG signal period is obtained. PMID:26334000

  10. Mode-filtered large-core fiber for short-pulse delivery with reduced nonlinear effects

    PubMed Central

    Moon, Sucbei; Liu, Gangjun; Chen, Zhongping

    2012-01-01

    We present a large-core fiber (LCF) with a reduced nonlinear property for a single-mode beam delivery of intense ultrashort pulses. A tapered-fiber mode filter was fabricated in an LCF with the core diameter decreased from 20 μm to 6 μm at the tapered waist region surrounded by index-matched liquid. By the tapered geometry, the high-order mode was rejected so that our mode-filtered LCF acted as a single-mode fiber despite the multimode property of the original LCF. It has been found that this fiber class is suitable for applications, such as an endoscopic multiphoton microscope, that demand a flexible short-distance (<4 m) delivery medium of ultrashort pulses. PMID:21886211

  11. Adaptive anisotropic gaussian filtering to reduce acquisition time in cardiac diffusion tensor imaging.

    PubMed

    Mazumder, Ria; Clymer, Bradley D; Mo, Xiaokui; White, Richard D; Kolipaka, Arunark

    2016-06-01

    Diffusion tensor imaging (DTI) is used to quantify myocardial fiber orientation based on helical angles (HA). Accurate HA measurements require multiple excitations (NEX) and/or several diffusion encoding directions (DED). However, increasing NEX and/or DED increases acquisition time (TA). Therefore, in this study, we propose to reduce TA by implementing a 3D adaptive anisotropic Gaussian filter (AAGF) on the DTI data acquired from ex-vivo healthy and infarcted porcine hearts. DTI was performed on ex-vivo hearts [9-healthy, 3-myocardial infarction (MI)] with several combinations of DED and NEX. AAGF, mean (AVF) and median filters (MF) were applied on the primary eigenvectors of the diffusion tensor prior to HA estimation. The performance of AAGF was compared against AVF and MF. Root mean square error (RMSE), concordance correlation-coefficients and Bland-Altman's technique was used to determine optimal combination of DED and NEX that generated the best HA maps in the least possible TA. Lastly, the effect of implementing AAGF on the infarcted porcine hearts was also investigated. RMSE in HA estimation for AAGF was lower compared to AVF or MF. Post-filtering (AAGF) fewer DED and NEX were required to achieve HA maps with similar integrity as those obtained from higher NEX and/or DED. Pathological alterations caused in HA orientation in the MI model were preserved post-filtering (AAGF). Our results demonstrate that AAGF reduces TA without affecting the integrity of the myocardial microstructure. PMID:26843150

  12. Kalman filtering approach for reducing gyroscope noise effects in stabilized platforms

    NASA Astrophysics Data System (ADS)

    Algrain, Marcelo C.

    1992-11-01

    Stabilization systems use gyroscopes typically mounted along side-sensing or imaging devices isolated from external rotations in inertial space. The gyroscopes measure the residual angular motion of the platform stabilized member. The better the stabilization, the smaller the sensed residual motion is. Conceivably, the residual motion (angular jitter) could be as small as the noise in the gyroscope outputs. This represents a low SNR case. Under such conditions, lower noise gyroscopes would be required to further reduce angular jitter, at considerably higher expense. Alternatively, the performance of the stabilization system can be significantly enhanced through noise-reducing optimal filtering techniques. The latter approach uses angular velocity estimates that are more accurate than raw measurements to stabilize the platform. This paper presents a new Kalman filtering technique that reduces the mean-square-error (MSE) between actual angular velocity values and estimated ones by an order of magnitude compared to the MSE resulting from direct measurements even under extremely low SNR conditions. The electronically improved angular motion measurements can be fed into the platform stabilization control system instead of raw measurements, considerably reducing stabilization jitter.

  13. Kalman filtering approach for reducing gyroscope noise effects in stabilized platforms

    NASA Astrophysics Data System (ADS)

    Algrain, Marcelo C.

    Stabilization systems use gyroscopes typically mounted along side sensing or imaging devices being isolated from external rotations in inertial space. The gyroscopes measure the residual angular motion of the platform stabilized member. The better the stabilization the smaller the sensed residual motion is. Conceivably, the residual motion (angular jitter) could be as small as the noise in the gyroscope outputs. This represents a low signal-to-noise ratio case. Under such conditions, lower noise gyroscopes would be required to further reduce angular jitter, at considerably higher expense. Alternatively, the performance of the stabilization system can be significantly enhanced through noise reducing optimal filtering techniques. The latter approach uses angular velocity estimates that are more accurate than raw measurements to stabilize the platform, without resorting to more precise and costly lower-noise gyroscopes. This paper presents a new Kalman filtering technique that reduces the mean-square-error (MSE) between actual angular velocity values and estimated ones by an order of magnitude (when compared to the MSE resulting from direct measurements) even under extremely low signal-to-noise ratio conditions. The electronically improved angular motion measurements can be fed into the platform stabilization control system (instead of raw measurements) considerably reducing stabilization jitter.

  14. Filter-feeding bivalves can remove avian influenza viruses from water and reduce infectivity

    PubMed Central

    Faust, Christina; Stallknecht, David; Swayne, David; Brown, Justin

    2009-01-01

    Avian influenza (AI) viruses are believed to be transmitted within wild aquatic bird populations through an indirect faecal–oral route involving contaminated water. This study examined the influence of filter-feeding bivalves, Corbicula fluminea, on the infectivity of AI virus in water. Clams were placed into individual flasks with distilled water inoculated 1:100 with a low pathogenic (LP) AI virus (A/Mallard/MN/190/99 (H3N8)). Viral titres in water with clams were significantly lower at 24 and 48 h post-inoculation compared to LPAI-infected water without clams. To determine whether clams affected the infectivity of AI viruses, 18 wood ducks (Aix sponsa) were divided into test groups and inoculated with a variety of treatments of clam supernatants, whole clams and water exposed to a high pathogenic (HP) AI (A/whooper swan/Mongolia/244/05 (H5N1)). None of the wood ducks inoculated with HPAI-infected water that was filtered by clams or that was inoculated with or fed tissue from these clams exhibited morbidity or mortality. All wood ducks exposed to either HPAI-infected water without clams or the original viral inoculum died. These results indicate that filter-feeding bivalves can remove and reduce the infectivity of AI viruses in water and demonstrate the need to examine biotic environmental factors that can influence AI virus transmission. PMID:19656788

  15. A method for reducing the level of spurious signals in surface acoustic wave filters

    NASA Astrophysics Data System (ADS)

    Borodii, Iu. N.; Grankin, I. M.; Zapunnyi, A. P.; Kolomeiko, A. V.

    1986-03-01

    A method for reducing spurious signals in surface acoustic wave (SAW) filters is proposed whereby both bulk and reflected wave signals are attenuated by electrodes of special configuration providing synphase addition of the useful signal and nonsynphase addition of spurious signal components. The electrodes of the input and output converters are made with a common focus point and equal angular apertures. The shape of the electrodes of the focusing converters on anisotropic crystal surfaces is determined by the corresponding SAW group velocity curve. An implementation of the method proposed here is examined together with some test results.

  16. Assessment of the capacity of vehicle cabin air inlet filters to reduce diesel exhaust-induced symptoms in human volunteers

    PubMed Central

    2014-01-01

    Background Exposure to particulate matter (PM) air pollution especially derived from traffic is associated with increases in cardiorespiratory morbidity and mortality. In this study, we evaluated the ability of novel vehicle cabin air inlet filters to reduce diesel exhaust (DE)-induced symptoms and markers of inflammation in human subjects. Methods Thirty healthy subjects participated in a randomized double-blind controlled crossover study where they were exposed to filtered air, unfiltered DE and DE filtered through two selected particle filters, one with and one without active charcoal. Exposures lasted for one hour. Symptoms were assessed before and during exposures and lung function was measured before and after each exposure, with inflammation assessed in peripheral blood five hours after exposures. In parallel, PM were collected from unfiltered and filtered DE and assessed for their capacity to drive damaging oxidation reactions in a cell-free model, or promote inflammation in A549 cells. Results The standard particle filter employed in this study reduced PM10 mass concentrations within the exposure chamber by 46%, further reduced to 74% by the inclusion of an active charcoal component. In addition use of the active charcoal filter was associated by a 75% and 50% reduction in NO2 and hydrocarbon concentrations, respectively. As expected, subjects reported more subjective symptoms after exposure to unfiltered DE compared to filtered air, which was significantly reduced by the filter with an active charcoal component. There were no significant changes in lung function after exposures. Similarly diesel exhaust did not elicit significant increases in any of the inflammatory markers examined in the peripheral blood samples 5 hour post-exposure. Whilst the filters reduced chamber particle concentrations, the oxidative activity of the particles themselves, did not change following filtration with either filter. In contrast, diesel exhaust PM passed through the

  17. Replacement of HEPA Filters at the LANL CMR Facility: Risks Reduced by Comprehensive Waste Characterization

    SciTech Connect

    Corpion, J.; Barr, A.; Martinez, P.; Bader, M.

    2002-02-28

    In March 2001, the Los Alamos National Laboratory (LANL) completed the replacement of 720 radioactively contaminated HEPA filters for $5.7M. This project was completed five months ahead of schedule and $6.0M under budget with no worker injuries or contaminations. Numerous health and safety, environmental, and waste disposal problems were overcome, including having to perform work in a radioactively contaminated work environment, that was also contaminated with perchlorates (potential explosive). High waste disposal costs were also an issue. A project risk analysis and government cost estimate determined that the cost of performing the work would be $11.8M. To reduce risk, a $1.2M comprehensive condition assessment was performed to determine the degree of toxic and radioactive contamination trapped on the HEPA filters; and to determine whether explosive concentrations of perchlorates were present. Workers from LANL and personnel from Waldheim International of Knoxville, TN collected hundreds of samples wearing personnel protective gear against radioactive, toxic, and explosive hazards. LANL also funded research at the New Mexico Institute of Mining and Technology to determine the explosivity of perchlorates. The data acquired from the condition assessment showed that toxic metals, toxic organic compounds, and explosive concentrations of perchlorates were absent. The data also showed that the extent of actinide metal contamination was less than expected, reducing the potential of transuranic waste generation by 50%. Consequently, $4.2M in cost savings and $1.8M in risk reduction were realized by increased worker productivity and waste segregation.

  18. Replacement of HEPA Filters at the LANL CMR Facility : risk reduced by comprehensive waste characterization

    SciTech Connect

    Corpion, J. C.

    2002-01-01

    In March 2001, the Los Alamos National Laboratory (LANL) completed the replacement of 720 radioactively contaminated HEPA filters for $5.7M. This project was completed five months ahead of schedule and $6.0M under budget with no worker injuries or contaminations. Numerous health and safety, environmental, and waste disposal problems were overcome, including having to perform work in a radioactively contaminated work environment, that was also contaminated with perchlorates (potential explosive). High waste disposal costs were also an issue. A project risk analysis and government cost estimate determined that the cost of performing the work would be $11.8M. To reduce risk, a $1.2M comprehensive condition assessment was performed to determine the degree of toxic and radioactive contamination trapped on the HEPA filters; and to determine whether explosive concentrations of perchlorates were present. Workers from LANL and personnel from Waldheim International of Knoxville, TN collected hundreds of samples wearing personnel protective gear against radioactive, toxic, and explosive hazards. LANL also funded research at the New Mexico Institute of Mining and Technology to determine the explosivity of perchlorates. The data acquired from the condition assessment showed that toxic metals, toxic organic compounds, and explosive concentrations of perchlorates were absent. The data also showed that the extent of actinide metal contamination was less than expected, reducing the potential of transuranic waste generation by 50%. Consequently, $4.2M in cost savings and $1.8M in risk reduction were realized by increased worker productivity and waste segregation.

  19. Scene-based nonuniformity correction based on bilateral filter with reduced ghosting

    NASA Astrophysics Data System (ADS)

    Li, Zhaolong; Shen, Tongsheng; Lou, Shuli

    2016-07-01

    In order to correct the nonuniformity noise of the IR imaging system, a nonuniformity correction deghosting algorithm based on high-brightness region detection was proposed. Firstly, the bilateral filter was used to filter the image. The high-brightness regions in the result image were detected, and the correction factors corresponding to the regions were reduced. And then, the positions were detected which are high-brightness pixels in former frame but are not in current frame, and the correction factors corresponding to the regions were enlarged. Thus, the wrong update of the correction factor caused by high-brightness region of both the current frame and the previous frame was reduced. The correction method was validated using a real image sequence. The experimental results showed that the suppression effect of the proposed algorithm on the 'ghost' effect caused by the high-brightness region is better than the other two algorithms named SLTH-NUC and BFTH-NUC, respectively. Moreover, the proposed algorithm can also suppress the 'ghost' effect caused by the sharp edge of the scene.

  20. The use of wavelet filters for reducing noise in posterior fossa Computed Tomography images

    SciTech Connect

    Pita-Machado, Reinado; Perez-Diaz, Marlen Lorenzo-Ginori, Juan V. Bravo-Pino, Rolando

    2014-11-07

    Wavelet transform based de-noising like wavelet shrinkage, gives the good results in CT. This procedure affects very little the spatial resolution. Some applications are reconstruction methods, while others are a posteriori de-noising methods. De-noising after reconstruction is very difficult because the noise is non-stationary and has unknown distribution. Therefore, methods which work on the sinogram-space don’t have this problem, because they always work over a known noise distribution at this point. On the other hand, the posterior fossa in a head CT is a very complex region for physicians, because it is commonly affected by artifacts and noise which are not eliminated during the reconstruction procedure. This can leads to some false positive evaluations. The purpose of our present work is to compare different wavelet shrinkage de-noising filters to reduce noise, particularly in images of the posterior fossa within CT scans in the sinogram-space. This work describes an experimental search for the best wavelets, to reduce Poisson noise in Computed Tomography (CT) scans. Results showed that de-noising with wavelet filters improved the quality of posterior fossa region in terms of an increased CNR, without noticeable structural distortions.

  1. Documentation for subroutine REDUC3, an algorithm for the linear filtering of gridded magnetic data

    USGS Publications Warehouse

    Blakely, Richard J.

    1977-01-01

    Subroutine REDUC3 transforms a total field anomaly h1(x,y) , measured on a horizontal and rectangular grid, into a new anomaly h2(x,y). This new anomaly is produced by the same source as h1(x,y) , but (1) is observed at a different elevation, (2) has a source with a different direction of magnetization, and/or (3) has a different direction of residual field. Case 1 is tantamount to upward or downward continuation. Cases 2 and 3 are 'reduction to the pole', if the new inclinations of both the magnetization and regional field are 90 degrees. REDUC3 is a filtering operation applied in the wave-number domain. It first Fourier transforms h1(x,y) , multiplies by the appropriate filter, and inverse Fourier transforms the result to obtain h2(x,y). No assumptions are required about the shape of the source or how the intensity of magnetization varies within it.

  2. Effects of reduced amounts of lipid unsaturation on chloroplast ultrastructure and photosynthesis in a mutant of Arabidopsis

    SciTech Connect

    McCourt, P.; Kunst, L.; Browse, J.; Somerville, C.R.

    1987-06-01

    A mutant of Arabidopsis thaliana with reduced content of C/sub 18:3/ and C/sub 16:3/ fatty acids in membrane lipids exhibited a 45% reduction in the cross-sectional area of chloroplasts and had a decrease of similar magnitude in the amount of chloroplast lamellar membranes. The reduction in chloroplast size was partially compensated by a 45% increase in the number of chloroplasts per cell in the mutant. When expressed on a chlorophyll basis the rates of CO/sub 2/-fixation and photosynthetic electron transport were not affected by these changes. Fluorescence polarization measurements indicated that the fluidity of the thylakoid membranes was not significantly altered by the mutation. Similarly, on the basis of temperature-induced fluorescence yield enhancement measurements, there was no significant effect on the thermal stability of chlorophyll-protein complexes in the mutant. These observations suggest that the high content of trienoic fatty acids in chloroplast lipids may be an important factor regulating organelle biogenesis but is not required to support normal levels of the photosynthetic activities associated with the thylakoid membranes.

  3. [Application of photodynamic therapy to reduce the amount of resection for non-small cell lung cancer].

    PubMed

    Akopov, A L; Rusanov, A A; Chistiakov, I V; Urtenova, M A; Kazakov, N V; Gerasin, A V; Papaian, G V

    2013-01-01

    A prospective analysis of results of combined treatment of 22 patients with central stage II-III non-small cell lung cancer (NSCLC) was performed (the defeat of the main bronchi or lower parts of the trachea), which initially had been regarded as unresectable or inoperable (12 patients for functional reasons could not pass pneumonectomy, and in 10 patients a contraindication to primary surgery was the involvement of the distal trachea in tumor), but underwent surgery after preoperative treatment.Combination therapy included preoperative endobronchial photodynamic therapy (PDT) and chemotherapy followed by surgery and intraoperative PDT resection margins. PDT was carried out with the use of chlorine E6 (Radachlorin) and light wavelength of 662 nm. Overall response rate after neoadjuvant treatment was 82 %, endoscopic remission was observed in 21 of 22 patients (95%). 10 patients underwent pneumonectomy, 12--lobectomy. 19 surgical interventions were regarded as radical (R0--86%), 3--as microscopically non-radical (R1--14%). Degree of lymphatic metastasis spreading pN0 was detected in 6 patients (27 %), pN1--in 14 (64%) and pN2--in 2 patients (9%). Surgical lethality was 5%. In the late time of the whole observation period none of the patients developed local recurrence. One-year survival was 95%, 3-year--91%. PDT can play an important role in combination with surgical treatment for NSCLC and reduces the amount of resection in part of initially unresectable or inoperable patients. PMID:24624784

  4. 42 CFR 412.162 - Process for reducing the base operating DRG payment amount and applying the value-based incentive...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 2 2014-10-01 2014-10-01 false Process for reducing the base operating DRG payment amount and applying the value-based incentive payment amount adjustment under the Hospital Value-Based Purchasing (VBP) Program. 412.162 Section 412.162 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN...

  5. 30 CFR 872.35 - When will OSM reduce the amount of prior balance replacement funds or certified in lieu funds...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false When will OSM reduce the amount of prior balance replacement funds or certified in lieu funds distributed to you? 872.35 Section 872.35 Mineral... the amount of prior balance replacement funds or certified in lieu funds distributed to you? (a)...

  6. 30 CFR 872.35 - When will OSM reduce the amount of prior balance replacement funds or certified in lieu funds...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false When will OSM reduce the amount of prior balance replacement funds or certified in lieu funds distributed to you? 872.35 Section 872.35 Mineral... the amount of prior balance replacement funds or certified in lieu funds distributed to you? (a)...

  7. 30 CFR 872.35 - When will OSM reduce the amount of prior balance replacement funds or certified in lieu funds...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false When will OSM reduce the amount of prior balance replacement funds or certified in lieu funds distributed to you? 872.35 Section 872.35 Mineral... the amount of prior balance replacement funds or certified in lieu funds distributed to you? (a)...

  8. 30 CFR 872.35 - When will OSM reduce the amount of prior balance replacement funds or certified in lieu funds...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false When will OSM reduce the amount of prior balance replacement funds or certified in lieu funds distributed to you? 872.35 Section 872.35 Mineral... the amount of prior balance replacement funds or certified in lieu funds distributed to you? (a)...

  9. 30 CFR 872.35 - When will OSM reduce the amount of prior balance replacement funds or certified in lieu funds...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false When will OSM reduce the amount of prior balance replacement funds or certified in lieu funds distributed to you? 872.35 Section 872.35 Mineral... the amount of prior balance replacement funds or certified in lieu funds distributed to you? (a)...

  10. Application of the Karhunen-Loeve transform temporal image filter to reduce noise in real-time cardiac cine MRI.

    PubMed

    Ding, Yu; Chung, Yiu-Cho; Raman, Subha V; Simonetti, Orlando P

    2009-06-21

    Real-time dynamic magnetic resonance imaging (MRI) typically sacrifices the signal-to-noise ratio (SNR) to achieve higher spatial and temporal resolution. Spatial and/or temporal filtering (e.g., low-pass filtering or averaging) of dynamic images improves the SNR at the expense of edge sharpness. We describe the application of a temporal filter for dynamic MR image series based on the Karhunen-Loeve transform (KLT) to remove random noise without blurring stationary or moving edges and requiring no training data. In this paper, we present several properties of this filter and their effects on filter performance, and propose an automatic way to find the filter cutoff based on the autocorrelation of the eigenimages. Numerical simulation and in vivo real-time cardiac cine MR image series spanning multiple cardiac cycles acquired using multi-channel sensitivity-encoded MRI, i.e., parallel imaging, are used to validate and demonstrate these properties. We found that in this application, the noise standard deviation was reduced to 42% of the original with no apparent image blurring by using the proposed filter cutoff. Greater noise reduction can be achieved by increasing the length of the image series. This advantage of KLT filtering provides flexibility in the form of another scan parameter to trade for SNR. PMID:19491455

  11. Digital filter based on the Fisher linear discriminant to reduce dead-time paralysis in photon counting

    NASA Astrophysics Data System (ADS)

    Sullivan, Shane Z.; Schmitt, Paul D.; DeWalt, Emma L.; Muir, Ryan D.; Simpson, Garth J.

    2013-03-01

    Photon counting represents the Poisson limit in signal to noise, but can often be complicated in imaging applications by detector paralysis, arising from the finite rise / fall time of the detector upon photon absorption. We present here an approach for reducing dead-time by generating a deconvolution digital filter based on optimizing the Fisher linear discriminant. In brief, two classes are defined, one in which a photon event is initiated at the origin of the digital filter, and one in the photon event is non-coincident with the filter origin. Linear discriminant analysis (LDA) is then performed to optimize the digital filter that best resolves the coincident and non-coincident training set data.1 Once trained, implementation of the filter can be performed quickly, significantly reducing dead-time issues and measurement bias in photon counting applications. Experimental demonstration of the LDA-filter approach was performed in fluorescence microscopy measurements using a highly convolved impulse response with considerable ringing. Analysis of the counts supports the capabilities of the filter in recovering deconvolved impulse responses under the conditions considered in the study. Potential additional applications and possible limitations are also considered.

  12. The application of the reduced order model Kalman filter to motion estimation of degraded image sequences. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Simpson, Elizabeth C.

    1989-01-01

    Motion estimation is a field of great interest because of its many applications in areas such as robotics and image coding. The optic flow method is one such scheme which, although fairly accurate, is prone to error in the presence of noise. This thesis describes the use of the reduced order model Kalman filter (ROMKF) in reducing errors in displacement estimation due to degradation of the sequence. The implementation of filtering and motion estimation algorithms on the SUN workstation is also discussed. Results from preliminary testing were used to determine the degrees of freedom available for the ROMKF in the SUN software. The tests indicated that increasing the state to the left leads to slight improvement over the minimum state case. Therefore, the software uses the minimum model, with the option of adding states to the left only. The ROMKF was then used in conjunction with a hierarchical pel recursive motion estimation algorithm. Applying the ROMKF to the degraded displacements themselves generally yielded slight improvements in cases with noise degradation and noise plus blur. Filtering the images of the degraded sequence prior to motion estimation was less effective in these cases. Both methods performed badly in the case of blur alone, resulting in increased displacement errors. This is thought to be due in part to filter artifacts. Some improvements were obtained by varying the filter parameters when filtering the displacements directly. This result suggests that further study in varying filter parameters may lead to better results. The results of this thesis indicate that the ROMKF can play a part in reducing motion estimation errors from degraded sequences. However, more work needs to be done before the use of the ROMKF can be a practical solution.

  13. Distortion invariant pattern recognition with phase filters

    NASA Technical Reports Server (NTRS)

    Rosen, Joseph; Shamir, Joseph

    1987-01-01

    A recently developed approach for pattern recognition using spatial filters with reduced tolerance requirements is employed for the generation of filters containing mainly phase information. As anticipated, the recognition levels were decreased, but they remain adequate for unambiguous identification together with appreciable amounts of distortion immunity. Furthermore, the information content of the filters is compatible with low devices like spatial light modulators.

  14. The critical flux method for reduced filter membrane fouling when monitoring high-solids digesters.

    PubMed

    Tait, Stephan; Carney, Christopher R; Batstone, Damien J

    2013-01-01

    Membrane fouling currently makes filtration of high-solids anaerobic sludges difficult and this is discouraging online monitoring of volatile fatty acids and control of high-solids digesters. The present study tests the critical flux approach to reduce membrane fouling. Filtration tests are performed on two sludges, filtered via a side-stream off two full-scale digesters. Sub-critical flux operating conditions (for minimal cake layer formation) are identified for each of the sludges and the filtration units are operated at these conditions to assess longer term performance. Results for one of the sludges (co-digested primary and secondary sludge) is found to be encouraging, showing that sufficient flux rates (up to 40 L m(-2) h(-1)) can be readily sustained to allow longer term digester monitoring and control. Filtration performance for this sludge did not deteriorate significantly over the test period. Results for the other test sludge (digested thermally hydrolyzed waste activated sludge) were not as favorable and indicated that application may be limited for very high solids digesters (>5% total solids concentration). Differences in filtration behavior for the two test sludges were ascribed to the presence of complex soluble organics, the concentration of sludge solids and their particle size. PMID:23666767

  15. Hyaluronic acid as a molecular filter and friction-reducing lubricant in the human inner ear.

    PubMed

    Anniko, M; Arnold, W

    1995-01-01

    Immunofluorescence for hyaluronic acid occurred intracellularly in morphologically highly specialized areas in the adult human inner ear, for instance in the cuticular plates of all types of hair cells, at the apposition between outer hair cells and Deiter's cell bodies and in the near-surface area of Hensen's cells. The cytoskeletal organization in these regions is characterized by tightly packed filamentous proteins. Under physiological stimulus these regions undergo micromechanical change, either actively moving (force generation) or passively vibrating with changes in elasticity. Hyaluronic acid might therefore act as a friction-reducing molecular lubricant. In the lateral wall of the cochlea an accumulation of hyaluronic acid occurred in the loose connective tissue of the spiral ligament, in particular close to the stria vascularis. Due to its complex molecular network, hyaluronic acid offers considerable resistance to bulk flow of water and may exclude molecules. The basal cell region of the stria vascularis is thus given additional support to minimize (seal?) the stria vascularis towards all other areas except the endolymphatic space. Here, hyaluronic acid could act as a molecular filter. PMID:7731661

  16. Damage Detection in Flexible Plates through Reduced-Order Modeling and Hybrid Particle-Kalman Filtering.

    PubMed

    Capellari, Giovanni; Azam, Saeed Eftekhar; Mariani, Stefano

    2015-01-01

    Health monitoring of lightweight structures, like thin flexible plates, is of interest in several engineering fields. In this paper, a recursive Bayesian procedure is proposed to monitor the health of such structures through data collected by a network of optimally placed inertial sensors. As a main drawback of standard monitoring procedures is linked to the computational costs, two remedies are jointly considered: first, an order-reduction of the numerical model used to track the structural dynamics, enforced with proper orthogonal decomposition; and, second, an improved particle filter, which features an extended Kalman updating of each evolving particle before the resampling stage. The former remedy can reduce the number of effective degrees-of-freedom of the structural model to a few only (depending on the excitation), whereas the latter one allows to track the evolution of damage and to locate it thanks to an intricate formulation. To assess the effectiveness of the proposed procedure, the case of a plate subject to bending is investigated; it is shown that, when the procedure is appropriately fed by measurements, damage is efficiently and accurately estimated. PMID:26703615

  17. Damage Detection in Flexible Plates through Reduced-Order Modeling and Hybrid Particle-Kalman Filtering

    PubMed Central

    Capellari, Giovanni; Eftekhar Azam, Saeed; Mariani, Stefano

    2015-01-01

    Health monitoring of lightweight structures, like thin flexible plates, is of interest in several engineering fields. In this paper, a recursive Bayesian procedure is proposed to monitor the health of such structures through data collected by a network of optimally placed inertial sensors. As a main drawback of standard monitoring procedures is linked to the computational costs, two remedies are jointly considered: first, an order-reduction of the numerical model used to track the structural dynamics, enforced with proper orthogonal decomposition; and, second, an improved particle filter, which features an extended Kalman updating of each evolving particle before the resampling stage. The former remedy can reduce the number of effective degrees-of-freedom of the structural model to a few only (depending on the excitation), whereas the latter one allows to track the evolution of damage and to locate it thanks to an intricate formulation. To assess the effectiveness of the proposed procedure, the case of a plate subject to bending is investigated; it is shown that, when the procedure is appropriately fed by measurements, damage is efficiently and accurately estimated. PMID:26703615

  18. Reduced Complexity HMM Filtering With Stochastic Dominance Bounds: A Convex Optimization Approach

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, Vikram; Rojas, Cristian R.

    2014-12-01

    This paper uses stochastic dominance principles to construct upper and lower sample path bounds for Hidden Markov Model (HMM) filters. Given a HMM, by using convex optimization methods for nuclear norm minimization with copositive constraints, we construct low rank stochastic marices so that the optimal filters using these matrices provably lower and upper bound (with respect to a partially ordered set) the true filtered distribution at each time instant. Since these matrices are low rank (say R), the computational cost of evaluating the filtering bounds is O(XR) instead of O(X2). A Monte-Carlo importance sampling filter is presented that exploits these upper and lower bounds to estimate the optimal posterior. Finally, using the Dobrushin coefficient, explicit bounds are given on the variational norm between the true posterior and the upper and lower bounds.

  19. Influence of soil pH in vegetative filter strips for reducing soluble nutrient transport.

    PubMed

    Rahmana, Atikur; Rahmana, Shafiqur; Cihacek, Larry

    2014-08-01

    Low efficacy of vegetative filter strips (VFS) in reducing soluble nutrients has been reported in research articles. Solubility of phosphorus and nitrogen compounds is largely affected by pH of soil. Changing soil pH may result in a decrease in soluble nutrient transportation through VFS. This study was conducted to evaluate the effect of pH levels of VFS soil on soluble nutrient transport reduction from manure-borne runoff. Soil (loamy sand texture; bulk density 1.3 g cm-3) was treated with calcium carbonate to change pH at different pH treatment levels (5.5-6.5, 6.5-7.5, and 7.5-8.5), soil was packed into galvanized metal boxes, and tall fescue grasses were established in the boxes to simulate VFS. Boxes were placed in an open environment, tilted to a 3.0% slope, and 44.0 L manure-amended water was applied through the VFS by a pump at a rate of 1.45 L min-1. Water samples were collected at the inlet and outlet as well as from the leachate. Samples were analysed for ortho-phosphorus, ammonium nitrogen, nitrate nitrogen, and potassium. Highest transport reductions in ortho-phosphorus (42.4%) and potassium (20.5%) were observed at pH range 7.5-8.5. Ammonium nitrogen transport reduction was the highest at pH level of 6.5-7.5 and was 26.1%. Surface transport reduction in nitrate nitrogen was 100%, but leachate had the highest concentration of nitrate nitrogen. Mass transport reduction also suggested that higher pH in the VFS soil are effective in reducing some soluble nutrients transport. PMID:24956766

  20. Project Report: Reducing Color Rivalry in Imagery for Conjugated Multiple Bandpass Filter Based Stereo Endoscopy

    NASA Technical Reports Server (NTRS)

    Ream, Allen

    2011-01-01

    A pair of conjugated multiple bandpass filters (CMBF) can be used to create spatially separated pupils in a traditional lens and imaging sensor system allowing for the passive capture of stereo video. This method is especially useful for surgical endoscopy where smaller cameras are needed to provide ample room for manipulating tools while also granting improved visualizations of scene depth. The significant issue in this process is that, due to the complimentary nature of the filters, the colors seen through each filter do not match each other, and also differ from colors as seen under a white illumination source. A color correction model was implemented that included optimized filter selection, such that the degree of necessary post-processing correction was minimized, and a chromatic adaptation transformation that attempted to fix the imaged colors tristimulus indices based on the principle of color constancy. Due to fabrication constraints, only dual bandpass filters were feasible. The theoretical average color error after correction between these filters was still above the fusion limit meaning that rivalry conditions are possible during viewing. This error can be minimized further by designing the filters for a subset of colors corresponding to specific working environments.

  1. Switching between filter settings reduces the efficient utilization of visual working memory.

    PubMed

    Jost, Kerstin; Mayr, Ulrich

    2016-04-01

    The capacity limitation of working memory requires that only relevant information gains access to the workspace, while irrelevant information is kept out. Thus, the ability to use attention to filter out irrelevant information is an important factor in how efficiently the limited storage space is used. Here, we examined to what degree the requirement to flexibly change filter settings affects filtering efficiency. Participants were presented with visual objects in different colors, and a cue presented in advance indicated which objects had to be stored. The contralateral delay activity, an event-related brain potential that reflects working-memory load was used to assess filtering efficiency during the retention interval. The data of two experiments showed that when filter settings had to be adjusted on a trial-by-trial basis, more irrelevant information passed the gate to working memory. Moreover, this switching-induced filtering deficit was restricted to those items that matched the previous, but currently irrelevant, filter settings. Thus, lingering effects of the selection history seem to counteract goal-directed encoding, and thus constitute an important attentional limitation for the efficient utilization of our limited workspace. PMID:26450507

  2. Sorbent-amended compost filter socks in grassed waterways reduce nutrient losses in surface runoff from corn fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface runoff from fields used to grow row crops frequently has high concentrations of sediment, nutrients, and pesticides, particularly in the first few events after tillage and agrochemical application. Compost filter socks placed in grassed waterways can further reduce sediment concentration as ...

  3. 43 CFR 404.34 - Can Reclamation reduce the amount of non-Federal cost-share required for a feasibility study?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-Federal cost-share required for a feasibility study? 404.34 Section 404.34 Public Lands: Interior... for a feasibility study? Yes. Reclamation may reduce the non-Federal cost-share required for a feasibility study to an amount less than 50 percent of the study costs if: (a) Reclamation determines...

  4. 43 CFR 404.34 - Can Reclamation reduce the amount of non-Federal cost-share required for a feasibility study?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-Federal cost-share required for a feasibility study? 404.34 Section 404.34 Public Lands: Interior... for a feasibility study? Yes. Reclamation may reduce the non-Federal cost-share required for a feasibility study to an amount less than 50 percent of the study costs if: (a) Reclamation determines...

  5. 43 CFR 404.34 - Can Reclamation reduce the amount of non-Federal cost-share required for a feasibility study?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-Federal cost-share required for a feasibility study? 404.34 Section 404.34 Public Lands: Interior... for a feasibility study? Yes. Reclamation may reduce the non-Federal cost-share required for a feasibility study to an amount less than 50 percent of the study costs if: (a) Reclamation determines...

  6. Markov Model Predicts Changes in STH Prevalence during Control Activities Even with a Reduced Amount of Baseline Information

    PubMed Central

    Montresor, Antonio; Deol, Arminder; à Porta, Natacha; Lethanh, Nam; Jankovic, Dina

    2016-01-01

    Background Estimating the reduction in levels of infection during implementation of soil-transmitted helminth (STH) control programmes is important to measure their performance and to plan interventions. Markov modelling techniques have been used with some success to predict changes in STH prevalence following treatment in Viet Nam. The model is stationary and to date, the prediction has been obtained by calculating the transition probabilities between the different classes of intensity following the first year of drug distribution and assuming that these remain constant in subsequent years. However, to run this model longitudinal parasitological data (including intensity of infection) are required for two consecutive years from at least 200 individuals. Since this amount of data is not often available from STH control programmes, the possible application of the model in control programme is limited. The present study aimed to address this issue by adapting the existing Markov model to allow its application when a more limited amount of data is available and to test the predictive capacities of these simplified models. Method We analysed data from field studies conducted with different combination of three parameters: (i) the frequency of drug administration; (ii) the drug distributed; and (iii) the target treatment population (entire population or school-aged children only). This analysis allowed us to define 10 sets of standard transition probabilities to be used to predict prevalence changes when only baseline data are available (simplified model 1). We also formulated three equations (one for each STH parasite) to calculate the predicted prevalence of the different classes of intensity from the total prevalence. These equations allowed us to design a simplified model (SM2) to obtain predictions when the classes of intensity at baseline were not known. To evaluate the performance of the simplified models, we collected data from the scientific literature on

  7. Photosynthetic electron sinks in transgenic tobacco with reduced amounts of Rubisco: little evidence for significant Mehler reaction.

    PubMed

    Ruuska, S A; Badger, M R; Andrews, T J; von Caemmerer, S

    2000-02-01

    Transgenic tobacco (Nicotiana tabacum L. cv. W38) plants with an antisense gene directed against the mRNA of the small subunit of Rubisco were used to investigate the role of O2 as an electron acceptor during photosynthesis. The reduction in Rubisco has reduced the capacity for CO2-fixation in these plants without a similar reduction in electron transport capacity. Concurrent measurements of chlorophyll fluorescence and CO2 assimilation at different CO2 and O2 partial pressures showed close linear relationships between chloroplast electron transport rates calculated from chlorophyll fluorescence and those calculated from CO2-fixation. These relationships were similar for wild-type and transgenic plants, indicating that the reduced capacity for CO2 fixation in the transgenic plants did not result in extra electron transport not associated with the photosynthetic carbon reduction (PCR) or photorespiratory carbon oxidation (PCO) cycle. This was further investigated with mass spectrometric measurements of 16O2 and 18O2 exchange made concurrently with measurements of chlorophyll fluorescence. In all tobacco lines the rates of 18O2 uptake in the dark were similar to the 18O2 uptake rates at very high CO2 partial pressures in the light. Rates of oxygenase activity calculated from 18O2 uptake at the compensation point were linearly related to the Rubisco content of leaves. The ratios of oxygenase to carboxylase rates were calculated from measurements of 16O2 evolution and 18O2 uptake at the compensation point. These ratios were lower in the transgenic plants, consistent with their higher CO2 compensation points. It is concluded that although there may be some electron transport to O2 to balance conflicting demands of NADPH to ATP requirements, this flux must decrease in proportion with the reduced demand for ATP and NADPH consumption in the transgenic lines. The altered balance between electron transport and Rubisco capacity, however, does not result in rampant electron

  8. Apparatus and method to reduce automotive emissions using filter catalyst interactive with Uego

    SciTech Connect

    Anderson, M.J.

    1992-01-28

    This patent describes a system for cleansing the gaseous emission stream generated by the combustion of an A/F mixture within cylinders of an internal combustion engine. It comprises a low mass, three-way filter catalyst stationed close to the source of the stream effective to affect substantially the entire emission stream by filtering out random combustion effects within the stream, the filter catalyst being limited in conversion efficiency to less than that of the main catalyst; a high mass, three-way main catalyst stationed downstream of the filter catalyst effective to convert the remainder of noxious emissions in the stream to desired levels; a continuous universal exhaust gas oxygen sensor stationed in the stream between the catalysts effective to symmetrically and accurately indicate the level of oxygen within the stream leaving the filter catalyst within a time response period of less than 60 milliseconds; and proportional control means for adjusting in closed loop the A/F ratio of the mixture in interactive response to a deviation of the sensed oxygen level from a target level.

  9. A filter for reducing the angular dependence of LiF; Ti, Mg for beta radiation

    SciTech Connect

    Akabani, G.; Poston, J.W. Sr. )

    1990-06-01

    This paper reports on an improvement in the angular dependence of LiF:Ti,Mg (TAD-100) for beta radiation which was achieved by using a special filter design which produced a constant dosimeter response over a range of +70{degrees} and {minus}70{degrees}. The filter material used was acetate. The filter design was tested with three different beta sources, Sr/Y-90, Tl-204 and Pm-147 with average energies of 0.8, 0.24 and 0.06 MeV, respectively. The average response at 180 degrees of the new filtered dosimeter differed by less than 5% when compared to the response at zero degrees. An average decrease in sensitivity of 53% for Sr-90, 70% for Tl-204 and 67% for Pm-147 was obtained due to filter use. All doses were calculated for a depth dose in tissue of 0.07 mm equivalent to 7 mg/cm{sup 2} as is recommended in ICRP Publication 26. A comparison of the energy dependence for a bare TAD-100 at 0.0 mm and 0.07 mm depth in tissue was obtained.

  10. Membrane bioreactors for municipal wastewater treatment - a viable option to reduce the amount of polar pollutants discharged into surface waters?

    PubMed

    Weiss, Stefan; Reemtsma, Thorsten

    2008-08-01

    The potential of a lab-scale membrane bioreactor (MBR) to remove polar pollutants from municipal wastewater was studied for industrial and household chemicals over a period of 22 months parallel to a conventional activated sludge (CAS) treatment. For half of the compounds, such as benzotriazole, 5-tolyltriazole (5-TTri), benzothiazole-2-sulfonate and 1,6-naphthalene disulfonate (1,6-NDSA), removal by MBR was significantly better than in CAS, while no improvement was recorded for the other half (1,5-NDSA, 1,3-NDSA, 4-TTri and naphthalene-1-sulfonate). The influence of operational conditions on trace pollutant removal by MBR was studied but no significant effects were found for variation of hydraulic retention time (7h-14h) and sludge retention time (26d-102d), suggesting that the lowest values selected have already been high enough for good removal. It is shown that the seemingly inconsistent results reported here and in previous studies regarding the comparison of trace pollutant removal in MBR and CAS are highly consistent. MBR is neither superior for well degradable compounds that are already extensively degraded in CAS treatment nor for recalcitrant compounds that are not amenable to biodegradation. For most compounds of intermediate removal in CAS treatment (15-80%), among them pharmaceuticals, personal care products and industrial chemicals, the MBR is clearly superior and reduces the effluent concentration by 20-50%. Despite of this clear benefit of MBR, the effect is not pronounced enough to serve as a sole argument for employing MBR in municipal wastewater treatment. PMID:18684484

  11. Filter-feeding bivalves can remove avian influenza viruses from water and reduce infectivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza (AI) viruses are transmitted within wild aquatic bird populations through an indirect fecal-oral route involving fecal-contaminated water. In this study, the influence of filter-feeding bivalves, Corbicula fluminea, on the infectivity of AI virus in water was examined. A single cla...

  12. Feasibility of reduced-dose 3D/4D-DSA using a weighted edge preserving filter

    NASA Astrophysics Data System (ADS)

    Oberstar, Erick L.; Speidel, Michael A.; Davis, Brian J.; Strother, Charles; Mistretta, Charles

    2016-03-01

    A conventional 3D/4D digital subtraction angiogram (DSA) requires two rotational acquisitions (mask and fill) to compute the log-subtracted projections that are used to reconstruct a 3D/4D volume. Since all of the vascular information is contained in the fill acquisition, it is hypothesized that it is possible to reduce the x-ray dose of the mask acquisition substantially and still obtain subtracted projections adequate to reconstruct a 3D/4D volume with noise level comparable to a full dose acquisition. A full dose mask and fill acquisition were acquired from a clinical study to provide a known full dose reference reconstruction. Gaussian noise was added to the mask acquisition to simulate a mask acquisition acquired at 10% relative dose. Noise in the low-dose mask projections was reduced with a weighted edge preserving (WEP) filter designed to preserve bony edges while suppressing noise. 2D log-subtracted projections were computed from the filtered low-dose mask and full-dose fill projections, and then 3D/4D-DSA reconstruction algorithms were applied. Additional bilateral filtering was applied to the 3D volumes. The signal-to-noise ratio measured in the filtered 3D/4D-DSA volumes was compared to the full dose case. The average ratio of filtered low-dose SNR to full-dose SNR was 1.07 for the 3D-DSA and 1.05 for the 4D-DSA, indicating the method is a feasible approach to restoring SNR in DSA scans acquired with a low-dose mask. The method was also tested in a phantom study with full dose fill and 22% dose mask.

  13. 43 CFR 404.34 - Can Reclamation reduce the amount of non-Federal cost-share required for a feasibility study?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Can Reclamation reduce the amount of non-Federal cost-share required for a feasibility study? 404.34 Section 404.34 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR RECLAMATION RURAL WATER SUPPLY PROGRAM Cost-Sharing § 404.34...

  14. 43 CFR 404.34 - Can Reclamation reduce the amount of non-Federal cost-share required for a feasibility study?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Can Reclamation reduce the amount of non-Federal cost-share required for a feasibility study? 404.34 Section 404.34 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR RECLAMATION RURAL WATER SUPPLY PROGRAM Cost-Sharing § 404.34...

  15. Simultaneous retrieval of total ozone column amounts and cloud/aerosol optical depths from multi-channel, moderate bandwidth filter instruments

    NASA Astrophysics Data System (ADS)

    Stamnes, Knut; Fan, Lingling; Li, Wei; Dahlback, Arne; Stamnes, Jakob; Stamnes, Snorre

    2015-04-01

    A new method is presented based on using neural networks (NN) to analyze ultraviolet (UV) irradiance data recorded by multi-channel, moderate bandwidth filter instruments. Application of the NN method to three years of data obtained by a NILU-UV multi-channel, moderate bandwidth filter instrument, revealed that compared to a traditional look-up table (LUT) method, the NN method yielded better agreement against the Ozone Monitoring Instrument (OMI) with a 1% decrease in relative difference and a significant increase in the correlation of total ozone column (TOC) values. Furthermore, this new method resulted in larger number of valid retrievals (daily average values within a meaningful range of 200-500 DU) than the LUT method. Compared with NN retrievals based on NILU-UV irradiance measurements, TOC values obtained from OMI were underestimated under cloudy conditions. Cloud optical depth (COD) values derived by the NN method were more reliable than corresponding results derived by the LUT method, the latter results were less accurate for heavy cloud cover, broken cloud situations or snow-covered ground. The potential for retrieving aerosol optical depth (AOD) values under cloud-free conditions will be discussed. The cloud-aerosol information obtained by irradiance instruments such as the NILU-UV can be used in conjunction with a radiative transfer model to estimate cloud/aerosol radiative forcing and hence the impact of clouds and aerosols on the radiative energy balance. Deployment of multi-channel, moderate bandwidth filter instruments at AERONET sites and analysis of such data in conjunction with AERONET and satellite remote sensing data can provide crucial information needed for the assessment of the influence of ozone, clouds, and aerosols on climate.

  16. Biochar filters reduced the toxic effects of nickel on tomato (Lycopersicon esculentum L.) grown in nutrient film technique hydroponic system.

    PubMed

    Mosa, Ahmed; El-Banna, Mostafa F; Gao, Bin

    2016-04-01

    This work used the nutrient film technique to evaluate the role of biochar filtration in reducing the toxic effects of nickel (Ni(2+)) on tomato growth. Three hydroponic treatments: T1 (control), T2 (with Ni(2+)), and T3 (with Ni(2+) and biochar) were used in the experiments. Scanning electron microscopy equipped with energy dispersive X-ray spectroscopy and Fourier transform spectroscopy was used to characterize the pre- and post-treatment biochar samples. The results illustrated that precipitation, ion exchange, and complexation with surface functional groups were the potential mechanisms of Ni(2+) removal by biochar. In comparison to the control, the T2 treatment showed severe Ni-stress with alterations in cell wall structure, distortions in cell nucleus, disturbances in mitochondrial system, malformations in stomatal structure, and abnormalities in chloroplast structure. The biochar filters in T3 treatment reduced dysfunctions of cell organelles in root and shoot cells. Total chlorophyll concentration decreased by 41.6% in T2 treatment. This reduction, however, was only 20.8% due to the protective effect of the biochar filters. The presence of Ni(2+) in the systems reduced the tomato fruit yield 58.5% and 31.9% in T2 and T3, respectively. Nickel concentrations reached the toxic limit in roots, shoots, and fruits in T2, which were not observed in T3. Biochar filters in T3 also minimized the dramatic reductions in nutrients concentration in roots, shoots, and fruits, which occurred in T2 treatment due to the severe Ni-stress. Findings from this work suggested that biochar filters can be used on farms as a safeguard for wastewater irrigation. PMID:26866963

  17. Moiré reducing two-dimensional diffractive optical low-pass filter made from molded plastic

    NASA Astrophysics Data System (ADS)

    Sakohira, Yosuke; Yamamoto, Kazuya; Okada, Makoto

    2016-03-01

    A two dimensional sinusoid diffraction grating is developed for a moiré-reducing low-pass filter. Typical display units have image pixels arranged systematically in two dimensions, with non-illuminating regions between the image pixels. Using a conventional lens to view this display, the image pixels and the region between the pixels are both magnified, and the resulting image is unpleasant to the human eye, especially with color displays, called the screen door effect. This pixel problem is typically solved with a low-pass filter using a diffraction grating. However, depending on the period of the diffraction grating compared to the period of the image pixels, moiré can be seen. In recent years, organic electroluminescence displays with a small fill factor are growing popular, but such displays are usually more prone to the screen door effect and moiré. With conventional optical low-pass filters, only the pixel pitch in the vertical and horizontal directions are taken into account, but this is insufficient with small fill-factor pixels, and consideration for various diagonal periods is needed. A two dimensional sinusoid structure diffraction grating is developed for a moiré-reducing low-pass filter. The angle of the grating with the image pixel arrangement, the distance between the display and the grating, the grating depth, and the grating period are all chosen appropriately, and take into account multiple non-adjacent diagonal image pixel periods for all colors, consequently reducing moiré and the screen door effect. We present the calculations and evaluation results from plastic samples made by lithography tooled molds.

  18. Small amount of reduce graphene oxide modified Li4Ti5O12 nanoparticles for ultrafast high-power lithium ion battery

    NASA Astrophysics Data System (ADS)

    Chen, Chengcheng; Huang, Yanan; Zhang, Hao; Wang, Xiaofeng; Li, Guoyang; Wang, Yijing; Jiao, Lifang; Yuan, Huatang

    2015-03-01

    Small amount of reduce graphene oxide (rGO) nanosheets modified Li4Ti5O12 nanoparticles composite has been synthesized by a facile and environmental in-situ hydrothermal reaction with subsequent annealing. The small amount of rGO (only 1.2 wt. %) greatly improves the whole morphology and electrochemical performance of composite. The nanoparticles uniformly grow on the rGO nanosheets effective suppressing the agglomeration and enhancing the specific surface area. Meanwhile, the special discharge capacity is 187 mAh g-1 at 1 C and the high rates discharge capacity is 128 mAh g-1 at 80 C (discharge-charge time only 33s). In particular, the cells remain in good work condition after 2000 cycles at 80 C, which credibly evidence the excellent electrochemical performance as an anode for high-power LIBs.

  19. Ultrahigh-rate supercapacitors based on eletrochemically reduced graphene oxide for ac line-filtering

    PubMed Central

    Sheng, Kaixuan; Sun, Yiqing; Li, Chun; Yuan, Wenjing; Shi, Gaoquan

    2012-01-01

    The recent boom in multifunction portable electronic equipments requires the development of compact and miniaturized electronic circuits with high efficiencies, low costs and long lasting time. For the operation of most line-powered electronics, alternating current (ac) line-filters are used to attenuate the leftover ac ripples on direct current (dc) voltage busses. Today, aluminum electrolytic capacitors (AECs) are widely applied for this purpose. However, they are usually the largest components in electronic circuits. Replacing AECs by more compact capacitors will have an immense impact on future electronic devices. Here, we report a double-layer capacitor based on three-dimensional (3D) interpenetrating graphene electrodes fabricated by electrochemical reduction of graphene oxide (ErGO-DLC). At 120-hertz, the ErGO-DLC exhibited a phase angle of −84 degrees, a specific capacitance of 283 microfaradays per centimeter square and a resistor-capacitor (RC) time constant of 1.35 milliseconds, making it capable of replacing AECs for the application of 120-hertz filtering. PMID:22355759

  20. Ultrahigh-rate supercapacitors based on eletrochemically reduced graphene oxide for ac line-filtering.

    PubMed

    Sheng, Kaixuan; Sun, Yiqing; Li, Chun; Yuan, Wenjing; Shi, Gaoquan

    2012-01-01

    The recent boom in multifunction portable electronic equipments requires the development of compact and miniaturized electronic circuits with high efficiencies, low costs and long lasting time. For the operation of most line-powered electronics, alternating current (ac) line-filters are used to attenuate the leftover ac ripples on direct current (dc) voltage busses. Today, aluminum electrolytic capacitors (AECs) are widely applied for this purpose. However, they are usually the largest components in electronic circuits. Replacing AECs by more compact capacitors will have an immense impact on future electronic devices. Here, we report a double-layer capacitor based on three-dimensional (3D) interpenetrating graphene electrodes fabricated by electrochemical reduction of graphene oxide (ErGO-DLC). At 120-hertz, the ErGO-DLC exhibited a phase angle of -84 degrees, a specific capacitance of 283 microfaradays per centimeter square and a resistor-capacitor (RC) time constant of 1.35 milliseconds, making it capable of replacing AECs for the application of 120-hertz filtering. PMID:22355759

  1. Water Filters

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Aquaspace H2OME Guardian Water Filter, available through Western Water International, Inc., reduces lead in water supplies. The filter is mounted on the faucet and the filter cartridge is placed in the "dead space" between sink and wall. This filter is one of several new filtration devices using the Aquaspace compound filter media, which combines company developed and NASA technology. Aquaspace filters are used in industrial, commercial, residential, and recreational environments as well as by developing nations where water is highly contaminated.

  2. Application of the flux noise reducing filter for CO2 inverse modelling

    NASA Astrophysics Data System (ADS)

    Maksyutov, Shamil; Yaremchuk, Alexey

    2010-05-01

    Recent atmospheric remote sensing products from AIRS and GOSAT provide large volume of the observations but with larger errors and variance as compared to in-situ measurements, so efficient noise reduction techniques are required for inverse modeling of the surface fluxes. Inverse models of the atmospheric transport optimize regional or grid resolving surface CO2 fluxes to fit transport model simulation optimally to the observations. The optimization problem appears to be ill-posed so it is usually solved by applying regularization techniques. Most widely used regularization methods apply constraints on flux deviation from prior and/or from adjacent regions of same surface type (land-ocean, vegetation type), and from adjacent time periods. Convenient method for solving the problem of limited dimension is based on singular value decomposition (SVD) of the transport matrix, because it can decompose the solution space into a combination of the independent singular vectors. Introducing a simple constraint on fluxes limits amplitude of the corresponding singular vectors with larger reduction for smaller singular values. However this amplitude reduction is not sufficient in practice for inverse modeling of the regional CO2 fluxes, when we have large underconstrained regions in tropics. Alternatively other means of the amplitude reduction are also used, such as truncation, when all amplitudes below threshold singular value are set to zero. We apply a filter which is less abrupt is less abrupt compared to truncation but still suppressing strongly small singular value related vectors. Setting strength of a constraint is often done empirically. To decide a proper value of the cut-off singular value we suggest analyzing a dependence of the singular vector amplitude vs the singular value and set the cut-off value aiming at retaining most of useful information from observation. A graphical tool based on a plot of amplitude spectra is proposed. Advantage of the technique is

  3. Homomorphic filtering textural analysis technique to reduce multiplicative noise in the 11Oba nano-doped liquid crystalline compounds

    NASA Astrophysics Data System (ADS)

    Madhav, B. T. P.; Pardhasaradhi, P.; Manepalli, R. K. N. R.; Pisipati, V. G. K. M.

    2015-07-01

    The compound undecyloxy benzoic acid (11Oba) exhibits nematic and smectic-C phases while a nano-doped undecyloxy benzoic acid with ZnO exhibits the same nematic and smectic-C phases with reduced clearing temperature as expected. The doping is done with 0.5% and 1% ZnO molecules. The clearing temperatures are reduced by approximately 4 ° and 6 °, respectively (differential scanning calorimeter data). While collecting the images from a polarizing microscope connected with hot stage and camera, the illumination and reflectance combined multiplicatively and the image quality was reduced to identify the exact phase in the compound. A novel technique of homomorphic filtering is used in this manuscript through which multiplicative noise components of the image are separated linearly in the frequency domain. This technique provides a frequency domain procedure to improve the appearance of an image by gray level range compression and contrast enhancement.

  4. UK approach to assessing assays and filters designed to reduce the risk of transfusion-transmitted vCJD.

    PubMed

    Thomas, S; Turner, M L; Williamson, L M

    2013-09-01

    Three cases of vCJD transmission by blood transfusion have been reported in the UK, and a fourth case discovered at post-mortem. Modelling has been conducted to predict the number of cases that may occur in the future through transfusion, based on estimates of prevalence, infectivity and susceptibility, and a number of steps have been taken to reduce the risk of transmission. These include deferral of previously transfused donors, leucocyte depletion of all components, importation of plasma for certain patient groups and for fractionation, and the collection of the majority of platelets from single donors (by apheresis). However, even with these interventions, some future cases are still predicted. The UK-wide Advisory Committee on the Safety of Blood, Tissues and Organs (SaBTO) considers the evidence for clinical and cost-effectiveness of any proposed intervention, such as prion assays and filters, and makes recommendations to the governments of the UK. The development of prion assays is challenging as prions do not generate an immune response, do not have nucleic acid and are present in blood in very low concentrations against a high background of normal prion protein. It is critically important that prion assays show high levels of sensitivity and - especially -specificity for a healthy blood donor population. Assessment is impacted by the very short supply of positive human samples, necessitating the use of animal models. Filters that are capable of removing prions from blood components have been developed and CE marked, but it is again necessary to use animal models to study their efficacy. Guidelines have been produced for the assessment of the quality of red cells filtered through these devices, and a clinical safety study has recently been completed. In conclusion, the evaluation of screening assays and prion filters is challenging, time-consuming and costly, but these evaluations are critical to policy making. PMID:23928183

  5. A novel spherical shell filter for reducing false positives in automatic detection of pulmonary nodules in thoracic CT scans

    NASA Astrophysics Data System (ADS)

    van de Leemput, Sil; Dorssers, Frank; Ehteshami Bejnordi, Babak

    2015-03-01

    Early detection of pulmonary nodules is crucial for improving prognosis of patients with lung cancer. Computer-aided detection of lung nodules in thoracic computed tomography (CT) scans has a great potential to enhance the performance of the radiologist in detecting nodules. In this paper we present a computer-aided lung nodule detection system for computed tomography (CT) scans that works in three steps. The system first segments the lung using thresholding and hole filling. From this segmentation the system extracts candidate nodules using Laplacian of Gaussian. To reject false positives among the detected candidate nodules, multiple established features are calculated. We propose a novel feature based on a spherical shell filter, which is specifically designed to distinguish between vascular structures and nodular structures. The performance of the proposed CAD system was evaluated by partaking in the ANODE09 challenge, which presents a platform for comparing automatic nodule detection programs. The results from the challenge show that our CAD system ranks third among the submitted works, demonstrating the efficacy of our proposed CAD system. The results also show that our proposed spherical shell filter in combination with conventional features can significantly reduce the number of false positives from the detected candidate nodules.

  6. Constant Modulus Algorithm with Reduced Complexity Employing DFT Domain Fast Filtering

    NASA Astrophysics Data System (ADS)

    Yang, Yoon Gi; Lee, Chang Su; Yang, Soo Mi

    In this paper, a novel CMA (constant modulus algorithm) algorithm employing fast convolution in the DFT (discrete Fourier transform) domain is proposed. We propose a non-linear adaptation algorithm that minimizes CMA cost function in the DFT domain. The proposed algorithm is completely new one as compared to the recently introduced similar DFT domain CMA algorithm in that, the original CMA cost function has not been changed to develop DFT domain algorithm, resulting improved convergence properties. Using the proposed approach, we can reduce the number of multiplications to O(N log 2 N), whereas the conventional CMA has the computation order of O(N2). Simulation results show that the proposed algorithm provides a comparable performance to the conventional CMA.

  7. Reducing patients’ exposures to asthma and allergy triggers in their homes: an evaluation of effectiveness of grades of forced air ventilation filters

    PubMed Central

    Minegishi, Taeko; Allen, Joseph G.; McCarthy, John F.; Spengler, John D.; MacIntosh, David L.

    2014-01-01

    Objective Many interventions to reduce allergen levels in the home are recommended to asthma and allergy patients. One that is readily available and can be highly effective is the use of high performing filters in forced air ventilation systems. Methods We conducted a modeling analysis of the effectiveness of filter-based interventions in the home to reduce airborne asthma and allergy triggers. This work used “each pass removal efficiency” applied to health-relevant size fractions of particles to assess filter performance. We assessed effectiveness for key allergy and asthma triggers based on applicable particle sizes for cat allergen, indoor and outdoor sources of particles <2.5 µm in diameter (PM2.5), and airborne influenza and rhinovirus. Results Our analysis finds that higher performing filters can have significant impacts on indoor particle pollutant levels. Filters with removal efficiencies of >70% for cat dander particles, fine particulate matter (PM2.5) and respiratory virus can lower concentrations of those asthma triggers and allergens in indoor air of the home by >50%. Very high removal efficiency filters, such as those rated a 16 on the nationally recognized Minimum Efficiency Removal Value (MERV) rating system, tend to be only marginally more effective than MERV12 or 13 rated filters. Conclusions The results of this analysis indicate that use of a MERV12 or higher performing air filter in home ventilation systems can effectively reduce indoor levels of these common asthma and allergy triggers. These reductions in airborne allergens in turn may help reduce allergy and asthma symptoms, especially if employed in conjunction with other environmental management measures recommended for allergy and asthma patients. PMID:24555523

  8. Interaction between PVY HC-Pro and the NtCF1β-subunit reduces the amount of chloroplast ATP synthase in virus-infected tobacco.

    PubMed

    Tu, Yayi; Jin, Yongsheng; Ma, Dongyuan; Li, Heng; Zhang, Zhenqian; Dong, Jiangli; Wang, Tao

    2015-01-01

    The photosynthetic rate of virus-infected plants is always reduced. However, the molecular mechanism underlying this phenomenon remains unclear. The helper component-proteinase (HC-Pro) of Potato virus Y (PVY) was found in the chloroplasts of PVY-infected tobacco, indicating some new function of HC-Pro in the chloroplasts. We generated HC-Pro transgenic plants with a transit peptide to target the protein to chloroplast. The HC-Pro transgenic tobacco showed a decreased photosynthetic rate by 25% at the light intensity of 600 μmol m(-2) s(-1). Using a yeast two-hybrid screening assay to search for chloroplast proteins interacting with HC-Pro, we identified that PVY HC-Pro can interact with the chloroplast ATP synthase NtCF1β-subunit. This interaction was confirmed by GST pull-down and co-immunoprecipitation assays. HC-Pro didn't interfere with the activity of assembled ATP synthase in vitro. The HC-Pro/NtCF1β-subunit interaction might affect the assembly of ATP synthase complex. Quantitative western blot and immunogold labeling of the ATP synthase indicated that the amount of ATP synthase complex was decreased in both the HC-Pro transgenic and the PVY-infected tobacco. These results demonstrate that HC-Pro plays an important role in reducing the photosynthetic rate of PVY-infected plants, which is a completely new role of HC-Pro besides its multiple known functions. PMID:26499367

  9. Interaction between PVY HC-Pro and the NtCF1β-subunit reduces the amount of chloroplast ATP synthase in virus-infected tobacco

    PubMed Central

    Tu, Yayi; Jin, Yongsheng; Ma, Dongyuan; Li, Heng; Zhang, Zhenqian; Dong, Jiangli; Wang, Tao

    2015-01-01

    The photosynthetic rate of virus-infected plants is always reduced. However, the molecular mechanism underlying this phenomenon remains unclear. The helper component-proteinase (HC-Pro) of Potato virus Y (PVY) was found in the chloroplasts of PVY-infected tobacco, indicating some new function of HC-Pro in the chloroplasts. We generated HC-Pro transgenic plants with a transit peptide to target the protein to chloroplast. The HC-Pro transgenic tobacco showed a decreased photosynthetic rate by 25% at the light intensity of 600 μmol m−2 s−1. Using a yeast two-hybrid screening assay to search for chloroplast proteins interacting with HC-Pro, we identified that PVY HC-Pro can interact with the chloroplast ATP synthase NtCF1β-subunit. This interaction was confirmed by GST pull-down and co-immunoprecipitation assays. HC-Pro didn’t interfere with the activity of assembled ATP synthase in vitro. The HC-Pro/NtCF1β-subunit interaction might affect the assembly of ATP synthase complex. Quantitative western blot and immunogold labeling of the ATP synthase indicated that the amount of ATP synthase complex was decreased in both the HC-Pro transgenic and the PVY-infected tobacco. These results demonstrate that HC-Pro plays an important role in reducing the photosynthetic rate of PVY-infected plants, which is a completely new role of HC-Pro besides its multiple known functions. PMID:26499367

  10. Reduced wheel running and blunted effects of voluntary exercise in LPA1-null mice: The importance of assessing the amount of running in transgenic mice studies

    PubMed Central

    Castilla-Ortega, Estela; Rosell-Valle, Cristina; Blanco, Eduardo; Pedraza, Carmen; Chun, Jerold; de Fonseca, Fernando Rodríguez; Estivill-Torrús, Guillermo; Santín, Luis J.

    2014-01-01

    This work was aimed to assess whether voluntary exercise rescued behavioral and hippocampal alterations in mice lacking the lysophosphatidic acid LPA1 receptor (LPA1-null mice), studying the potential relationship between the amount of exercise performed and its effects. Normal and LPA1-null mice underwent 23 days of free wheel running and were tested for open-field behavior and adult hippocampal neurogenesis (cell proliferation, immature neurons, cell survival). Running decreased anxiety-like behavior in both genotypes but increased exploration only in the normal mice. While running affected all neurogenesis-related measures in normal mice (especially in the suprapyramidal blade of the dentate gyrus), only a moderate increase in cell survival was found in the mutants. Importantly, the LPA1-nulls showed notably reduced running. Analysis suggested that defective running in the LPA1-null mice could contribute to explain the scarce benefit of the voluntary exercise treatment. On the other hand, a literature review revealed that voluntary exercise is frequently used to modulate behavior and the hippocampus in transgenic mice, but half of the studies did not assess the quantity of running, overlooking any potential running impairments. This study adds evidence to the relevance of the quantity of exercise performed, emphasizing the importance of its assessment in transgenic mice research. PMID:24055600

  11. Increased stocking rate and associated strategic dry-off decision rules reduced the amount of nitrate-N leached under grazing.

    PubMed

    Roche, J R; Ledgard, S F; Sprosen, M S; Lindsey, S B; Penno, J W; Horan, B; Macdonald, K A

    2016-07-01

    The effect of intensive agricultural systems on the environment is of increasing global concern, and recent review articles have highlighted the need for sustainable intensification of food production. In grazing dairy systems, the leaching of nitrate-N (NO3-N) to groundwater is a primary environmental concern. A herd-level factor considered by many to be a key contributor to the amount of NO3-N leached from dairy pastures is stocking rate (SR), and some countries have imposed limits to reduce the risk of NO3-N loss to groundwater. The objective of the current experiment was to determine the effect of dairy cow SR on NO3-N leached in a grazing system that did not import feed from off-farm and had the same N fertilizer input. Five SR were evaluated (2.2, 2.7, 3.1, 3.7, and 4.3 cows/ha) in a completely randomized design (i.e., 2 replicates of each SR as independent farmlets) over 2 y. Pasture utilization, milk production/hectare, and days in milk/hectare increased with SR, but days in milk/cow and milk production/cow declined. The concentration of NO3-N in drainage water and the quantity of NO3-N leached/ha per year declined linearly with increasing SR, and the operating profit/kg NO3-N leached per ha increased. Higher SR was associated with fewer days in milk/cow, resulting in a reduction in estimated urine N excretion/cow (the main source of N leaching) during the climatically sensitive period for NO3-N leaching (i.e., late summer to winter). We hypothesized that the reduction in estimated urine N excretion per cow led to an increase in urinary N spread and reduced losses from urine patches. The results presented indicate that lowering SR may not reduce nitrate leaching and highlight the need for a full farm system-level analysis of any management change to determine its effect on productivity and environmental outcomes. PMID:27157574

  12. Effects of MERV 16 filters and routine work practices on enclosed cabs for reducing respirable dust and DPM exposures in an underground limestone mine

    PubMed Central

    Noll, J.D.; Cecala, A.B.; J.A.Organiscak; Rider, J.P.

    2015-01-01

    An effective technique to minimize miners’ respirable dust and diesel exposure on mobile mining equipment is to place mine operators in enclosed cabs with designed filtration and pressurization systems. Many factors affect the performance of these enclosed cab systems, and one of the most significant factors is the effectiveness of the filtration system. High-efficiency particulate air (HEPA)-type filters are typically used because they are highly efficient at capturing all types and sizes of particles, including those in the submicron range such as diesel particulate matter (DPM). However, in laboratory tests, minimum efficiency reporting value (MERV) 16 filters have proven to be highly efficient for capturing DPM and respirable dust. Also, MERV 16 filters can be less restrictive to cab airflow and less expensive than HEPA filters. To verify their effectiveness in the field, MERV 16 filters were used in the enclosed cab filtration system on a face drill and roof bolting mining machine and tested at an underground limestone mine. Test results showed that DPM and respirable dust concentrations were reduced by more than 90% when the cabs were properly sealed. However, when the cab door was opened periodically throughout the shift, the reduction efficiency of the MERV 16 filters was reduced to 80% on average. PMID:26236044

  13. Reduction in the amount of crosstalk with reduced number of focal spot rows in a grating array based zonal wavefront sensor

    NASA Astrophysics Data System (ADS)

    Pathak, Biswajit; Boruah, Bosanta R.

    2015-06-01

    The Shack Hartmann wavefront sensor (SHWS), named after Johannes Franz Hartmann and Roland Shack, is one of the most well-known and popularly used optical wavefront sensor that finds numerous applications in various optical technologies. SHWS samples the incident wavefront by means of a lenslet array to produce an array of regular 2D array of focal spots on the detector plane of a digital camera, in the case of an unaberrated plane wavefront. If the incident wavefront is aberrated or deviates from a plane wavefront, the respective focal spots get shifted from its reference positions corresponding to the regular grid. If the incident wavefront aberration increases or has a very large curvature, the focal spot of one lenslet may enter the detector sub-aperture of the nearby lenslet. Thus, the SHWS has a limited dynamic range that is restricted to aberrations which do not allow the sub-images to be displaced out from their own detector sub-array. It makes the SHWS sensitive to cross-talk when higher order aberrations are present thereby unavoidably a ecting the wavefront estimation process. The array of tiny lenses of the SHWS can be replaced by an array of gratings followed by a focusing lens, generating an array of focal spots which is similar to that as in the case of a SHWS. In this paper, the spatial frequency of such a grating array based zonal wavefront sensor is configured to produce lesser number of rows of focal spots. The reduction in the number of focal spot rows reduces the amount of cross talk in the vertical direction. In this paper we present preliminary experimental results to demonstrate the above stated reduction in crosstalk.

  14. Detection of Urothelial Carcinoma: Comparison of Reduced-Dose Iterative Reconstruction with Standard-Dose Filtered Back Projection.

    PubMed

    Bahn, Young Eun; Kim, See Hyung; Kim, Mi Jeong; Kim, Chan Sun; Kim, Young Hwan; Cho, Seung Hyun

    2016-05-01

    Purpose To prospectively assess radiation dose, image quality, and diagnostic performance of computed tomography (CT) urography for detection of urothelial carcinomas by performing reduced-dose scanning with iterative reconstruction (IR) compared with standard-dose scanning with filtered back projection (FBP). Materials and Methods The institutional review board approved the study with written informed patient consent. In total, 2163 patients at high risk for urothelial carcinomas randomly underwent standard-dose scanning with FBP (protocol A, 120 kVp for >80 kg body weight; protocol B, 100 kVp for 50-80 kg body weight) or reduced-dose scanning with IR (protocol C, 100 kVp for >80 kg body weight; protocol D, 80 kVp for 50-80 kg body weight). Objective image quality (signal-to-noise ratio and contrast-to-noise ratio) between the two groups with same weight range was measured for various regions of interest. Subjective image quality (visual image noise, artifact, ureter depiction, and overall image quality) and diagnostic accuracy (per lesion and per patient) were assessed with three- and five-point scores, respectively. Results Size-specific dose estimate (protocol A vs protocol C, 24.2 mGy vs 19.2 mGy, respectively; protocol B vs protocol D,13.9 mGy vs 8.8 mGy, respectively) was significantly lower in reduced-dose scanning (P < .001 for both). There were significantly higher signal-to-noise and contrast-to-noise ratios in reduced-dose scanning, except for the abdominal aorta (P < .05 for all). There was no significant difference in subjective image quality, except for artifacts in protocols B and D (range, 4-5 vs 3-4; P < .05). Per-lesion diagnostic accuracy was 90.8% (89 of 98, protocol A), 91.3% (105 of 115, protocol B), 92.9% (79 of 85, protocol C), and 88.8% (111 of 125, protocol D). Conclusion Reduced-dose scanning with IR showed dose reduction and no significant difference of image quality in detection of urothelial carcinomas, except for some artifacts in 80

  15. Reducing radiation dose by application of optimized low-energy x-ray filters to K-edge imaging with a photon counting detector

    NASA Astrophysics Data System (ADS)

    Choi, Yu-Na; Lee, Seungwan; Kim, Hee-Joung

    2016-01-01

    K-edge imaging with photon counting x-ray detectors (PCXDs) can improve image quality compared with conventional energy integrating detectors. However, low-energy x-ray photons below the K-edge absorption energy of a target material do not contribute to image formation in the K-edge imaging and are likely to be completely absorbed by an object. In this study, we applied x-ray filters to the K-edge imaging with a PCXD based on cadmium zinc telluride for reducing radiation dose induced by low-energy x-ray photons. We used aluminum (Al) filters with different thicknesses as the low-energy x-ray filters and implemented the iodine K-edge imaging with an energy bin of 34-48 keV at the tube voltages of 50, 70 and 90 kVp. The effects of the low-energy x-ray filters on the K-edge imaging were investigated with respect to signal-difference-to-noise ratio (SDNR), entrance surface air kerma (ESAK) and figure of merit (FOM). The highest value of SDNR was observed in the K-edge imaging with a 2 mm Al filter, and the SDNR decreased as a function of the filter thicknesses. Compared to the K-edge imaging with a 2 mm Al filter, the ESAK was reduced by 66%, 48% and 39% in the K-edge imaging with a 12 mm Al filter for 50 kVp, 70 kVp and 90 kVp, respectively. The FOM values, which took into account the ESAK and SDNR, were maximized for 8, 6 to 8 and 4 mm Al filters at 50 kVp, 70 kVp and 90 kVp, respectively. We concluded that the use of an optimal low-energy filter thickness, which was determined by maximizing the FOM, could significantly reduce radiation dose while maintaining image quality in the K-edge imaging with the PCXD.

  16. Reducing radiation dose by application of optimized low-energy x-ray filters to K-edge imaging with a photon counting detector.

    PubMed

    Choi, Yu-Na; Lee, Seungwan; Kim, Hee-Joung

    2016-01-21

    K-edge imaging with photon counting x-ray detectors (PCXDs) can improve image quality compared with conventional energy integrating detectors. However, low-energy x-ray photons below the K-edge absorption energy of a target material do not contribute to image formation in the K-edge imaging and are likely to be completely absorbed by an object. In this study, we applied x-ray filters to the K-edge imaging with a PCXD based on cadmium zinc telluride for reducing radiation dose induced by low-energy x-ray photons. We used aluminum (Al) filters with different thicknesses as the low-energy x-ray filters and implemented the iodine K-edge imaging with an energy bin of 34-48 keV at the tube voltages of 50, 70 and 90 kVp. The effects of the low-energy x-ray filters on the K-edge imaging were investigated with respect to signal-difference-to-noise ratio (SDNR), entrance surface air kerma (ESAK) and figure of merit (FOM). The highest value of SDNR was observed in the K-edge imaging with a 2 mm Al filter, and the SDNR decreased as a function of the filter thicknesses. Compared to the K-edge imaging with a 2 mm Al filter, the ESAK was reduced by 66%, 48% and 39% in the K-edge imaging with a 12 mm Al filter for 50 kVp, 70 kVp and 90 kVp, respectively. The FOM values, which took into account the ESAK and SDNR, were maximized for 8, 6 to 8 and 4 mm Al filters at 50 kVp, 70 kVp and 90 kVp, respectively. We concluded that the use of an optimal low-energy filter thickness, which was determined by maximizing the FOM, could significantly reduce radiation dose while maintaining image quality in the K-edge imaging with the PCXD. PMID:26733235

  17. Severe Extracellular Matrix Abnormalities and Chondrodysplasia in Mice Lacking Collagen Prolyl 4-Hydroxylase Isoenzyme II in Combination with a Reduced Amount of Isoenzyme I*

    PubMed Central

    Aro, Ellinoora; Salo, Antti M.; Khatri, Richa; Finnilä, Mikko; Miinalainen, Ilkka; Sormunen, Raija; Pakkanen, Outi; Holster, Tiina; Soininen, Raija; Prein, Carina; Clausen-Schaumann, Hauke; Aszódi, Attila; Tuukkanen, Juha; Kivirikko, Kari I.; Schipani, Ernestina; Myllyharju, Johanna

    2015-01-01

    Collagen prolyl 4-hydroxylases (C-P4H-I, C-P4H-II, and C-P4H-III) catalyze formation of 4-hydroxyproline residues required to form triple-helical collagen molecules. Vertebrate C-P4Hs are α2β2 tetramers differing in their catalytic α subunits. C-P4H-I is the major isoenzyme in most cells, and inactivation of its catalytic subunit (P4ha1−/−) leads to embryonic lethality in mouse, whereas P4ha1+/− mice have no abnormalities. To study the role of C-P4H-II, which predominates in chondrocytes, we generated P4ha2−/− mice. Surprisingly, they had no apparent phenotypic abnormalities. To assess possible functional complementarity, we established P4ha1+/−;P4ha2−/− mice. They were smaller than their littermates, had moderate chondrodysplasia, and developed kyphosis. A transient inner cell death phenotype was detected in their developing growth plates. The columnar arrangement of proliferative chondrocytes was impaired, the amount of 4-hydroxyproline and the Tm of collagen II were reduced, and the extracellular matrix was softer in the growth plates of newborn P4ha1+/−;P4ha2−/− mice. No signs of uncompensated ER stress were detected in the mutant growth plate chondrocytes. Some of these defects were also found in P4ha2−/− mice, although in a much milder form. Our data show that C-P4H-I can to a large extent compensate for the lack of C-P4H-II in proper endochondral bone development, but their combined partial and complete inactivation, respectively, leads to biomechanically impaired extracellular matrix, moderate chondrodysplasia, and kyphosis. Our mouse data suggest that inactivating mutations in human P4HA2 are not likely to lead to skeletal disorders, and a simultaneous decrease in P4HA1 function would most probably be required to generate such a disease phenotype. PMID:26001784

  18. Preoperative education and use of analgesic before onset of pain routinely for post-thoracotomy pain control can reduce pain effect and total amount of analgesics administered postoperatively.

    PubMed

    Kol, Emine; Alpar, Sule Ecevit; Erdoğan, Abdullah

    2014-03-01

    homogeneous distribution in both patient groups. The rate of pain, which was defined as sharp, stabbing, and exhausting, was higher in the control group than in the study group, and the difference between the two groups was statistically significant (p < .05). As the doses of analgesics used for pain management in both groups were compared, it was determined that analgesic consumption was lower in the study group than in the control group, and the difference was statistically significant (p < .05). As a result, it was determined that preoperative thoracic pain management education and analgesics administered postoperatively, before the onset of pain, reduced the amount of analgesics used in the first postoperative 48 hours. PMID:23485658

  19. Assessing the efficacy of tabs on filtering facepiece respirator straps to increase proper doffing techniques while reducing contact transmission of pathogens.

    PubMed

    Strauch, Amanda L; Brady, Tyler M; Niezgoda, George; Almaguer, Claudia M; Shaffer, Ronald E; Fisher, Edward M

    2016-10-01

    NIOSH-certified N95 filtering facepiece respirators (FFRs) are used in healthcare settings as a control measure to mitigate exposures to airborne infectious particles. When the outer surface of an FFR becomes contaminated, it presents a contact transmission risk to the wearer. The Centers for Disease Control and Prevention (CDC) guidance recommends that healthcare workers (HCWs) doff FFRs by grasping the straps at the back of the head to avoid contact with the potentially contaminated surface. Adherence to proper doffing technique is reportedly low due to numerous factors including difficulty in locating and grasping the straps. This study compares the impact of tabs placed on FFR straps to controls (without tabs) on proper doffing, ease of use and comfort, and reduction of transfer of contamination to the wearer. Utilizing a fluorescent agent as a tracer to track contamination from FFRs to hand and head areas of 20 human subjects demonstrated that there was no difference in tabbed FFR straps and controls with respect to promoting proper doffing (p = 0.48), but did make doffing easier (p = 0.04) as indicated by 7 of 8 subjects that used the tabs. Seven of the 20 subjects felt that FFRs with tabs were easier to remove, while only 2 of 20 indicated that FFRs without tabs were easier to remove. Discomfort was not a factor for either FFR strap type. When removing an FFR with contaminated hands, the use of the tabs significantly reduced the amount of tracer transfer compared to straps without tabs (p = 0.012). FFRs with tabs on the straps are associated with ease of doffing and significantly less transfer of the fluorescent tracer. PMID:27105142

  20. Impact of Orchard Fungicide Spraying on Lowering the Amount of Symbiotic Fungi in Bee Bread and Its Implications for Reduced Colony Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bee larvae depend on fungi to produce food (bee bread) from stored pollen as a developmental requirement. In the absence of or lower amounts of such fungi, chalkbrood disease (Ascosphaera apis) occurs, which is the highlight observation and the purpose for this chapter. Beebread is a competitive e...

  1. 42 CFR 137.86 - Is the Secretary prohibited from reducing the amount of funds required under Title V to make...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... amount of funds required under Title V to make funding available for self-governance monitoring or... required under Title V to make funding available for self-governance monitoring or administration by the... funding available for self-governance monitoring or administration....

  2. 42 CFR 137.86 - Is the Secretary prohibited from reducing the amount of funds required under Title V to make...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... amount of funds required under Title V to make funding available for self-governance monitoring or... required under Title V to make funding available for self-governance monitoring or administration by the... funding available for self-governance monitoring or administration....

  3. 42 CFR 137.86 - Is the Secretary prohibited from reducing the amount of funds required under Title V to make...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... amount of funds required under Title V to make funding available for self-governance monitoring or... required under Title V to make funding available for self-governance monitoring or administration by the... funding available for self-governance monitoring or administration....

  4. 42 CFR 137.86 - Is the Secretary prohibited from reducing the amount of funds required under Title V to make...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... amount of funds required under Title V to make funding available for self-governance monitoring or... required under Title V to make funding available for self-governance monitoring or administration by the... funding available for self-governance monitoring or administration....

  5. 42 CFR 137.86 - Is the Secretary prohibited from reducing the amount of funds required under Title V to make...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... amount of funds required under Title V to make funding available for self-governance monitoring or... required under Title V to make funding available for self-governance monitoring or administration by the... funding available for self-governance monitoring or administration....

  6. New type of magnetic tunnel junction based on spin filtering through a reduced symmetry oxide: FeCo|Mg3B2O6|FeCo.

    PubMed

    Stewart, Derek A

    2010-01-01

    Magnetic tunnel junctions with high-tunneling magnetoresistance values such as Fe|MgO|Fe capitalize on spin filtering in the oxide region based on the band symmetry of incident electrons. However, these structures rely on magnetic leads and oxide regions of the same cubic symmetry class. A new magnetic tunnel junction (FeCo|Mg(3)B(2)O(6)|FeCo) is presented that uses a reduced symmetry oxide region (orthorhombic) to provide spin filtering between the two cubic magnetic leads. Complex band structure analysis of Mg(3)B(2)O(6) based on density functional calculations shows that significant spin filtering could occur in this system. This new type of magnetic tunnel junction may have been fabricated already and can explain recent experimental studies of rf-sputtered FeCoB|MgO|FeCoB junctions where there is significant B diffusion into the MgO region. PMID:20017563

  7. A Cluster Randomized Controlled Trial to Reduce Childhood Diarrhea Using Hollow Fiber Water Filter and/or Hygiene–Sanitation Educational Interventions

    PubMed Central

    Lindquist, Erik D.; George, C. M.; Perin, Jamie; Neiswender de Calani, Karen J.; Norman, W. Ray; Davis, Thomas P.; Perry, Henry

    2014-01-01

    Safe domestic potable water supplies are urgently needed to reduce childhood diarrheal disease. In periurban neighborhoods in Cochabamba, Bolivia, we conducted a cluster randomized controlled trial to evaluate the efficacy of a household-level hollow fiber filter and/or behavior change communication (BCC) on water, sanitation, and hygiene (WASH) to reduce the diarrheal disease in children less than 5 years of age. In total, 952 households were followed for a period of 12 weeks post-distribution of the study interventions. Households using Sawyer PointONE filters had significantly less diarrheal disease compared with the control arm during the intervention period, which was shown by diarrheal prevalence ratios of 0.21 (95% confidence interval [95% CI] = 0.15–0.30) for the filter arm and 0.27 (95% CI = 0.22–0.34) for the filter and WASH BCC arm. A non-significant reduction in diarrhea prevalence was reported in the WASH BCC study arm households (0.71, 95% CI = 0.59–0.86). PMID:24865680

  8. A cluster randomized controlled trial to reduce childhood diarrhea using hollow fiber water filter and/or hygiene-sanitation educational interventions.

    PubMed

    Lindquist, Erik D; George, C M; Perin, Jamie; Neiswender de Calani, Karen J; Norman, W Ray; Davis, Thomas P; Perry, Henry

    2014-07-01

    Safe domestic potable water supplies are urgently needed to reduce childhood diarrheal disease. In periurban neighborhoods in Cochabamba, Bolivia, we conducted a cluster randomized controlled trial to evaluate the efficacy of a household-level hollow fiber filter and/or behavior change communication (BCC) on water, sanitation, and hygiene (WASH) to reduce the diarrheal disease in children less than 5 years of age. In total, 952 households were followed for a period of 12 weeks post-distribution of the study interventions. Households using Sawyer PointONE filters had significantly less diarrheal disease compared with the control arm during the intervention period, which was shown by diarrheal prevalence ratios of 0.21 (95% confidence interval [95% CI] = 0.15-0.30) for the filter arm and 0.27 (95% CI = 0.22-0.34) for the filter and WASH BCC arm. A non-significant reduction in diarrhea prevalence was reported in the WASH BCC study arm households (0.71, 95% CI = 0.59-0.86). PMID:24865680

  9. Optimizing mini-ridge filter thickness to reduce proton treatment times in a spot-scanning synchrotron system

    SciTech Connect

    Courneyea, Lorraine; Beltran, Chris Tseung, Hok Seum Wan Chan; Yu, Juan; Herman, Michael G.

    2014-06-15

    Purpose: Study the contributors to treatment time as a function of Mini-Ridge Filter (MRF) thickness to determine the optimal choice for breath-hold treatment of lung tumors in a synchrotron-based spot-scanning proton machine. Methods: Five different spot-scanning nozzles were simulated in TOPAS: four with MRFs of varying maximal thicknesses (6.15–24.6 mm) and one with no MRF. The MRFs were designed with ridges aligned along orthogonal directions transverse to the beam, with the number of ridges (4–16) increasing with MRF thickness. The material thickness given by these ridges approximately followed a Gaussian distribution. Using these simulations, Monte Carlo data were generated for treatment planning commissioning. For each nozzle, standard and stereotactic (SR) lung phantom treatment plans were created and assessed for delivery time and plan quality. Results: Use of a MRF resulted in a reduction of the number of energy layers needed in treatment plans, decreasing the number of synchrotron spills needed and hence the treatment time. For standard plans, the treatment time per field without a MRF was 67.0 ± 0.1 s, whereas three of the four MRF plans had treatment times of less than 20 s per field; considered sufficiently low for a single breath-hold. For SR plans, the shortest treatment time achieved was 57.7 ± 1.9 s per field, compared to 95.5 ± 0.5 s without a MRF. There were diminishing gains in time reduction as the MRF thickness increased. Dose uniformity of the PTV was comparable across all plans; however, when the plans were normalized to have the same coverage, dose conformality decreased with MRF thickness, as measured by the lung V20%. Conclusions: Single breath-hold treatment times for plans with standard fractionation can be achieved through the use of a MRF, making this a viable option for motion mitigation in lung tumors. For stereotactic plans, while a MRF can reduce treatment times, multiple breath-holds would still be necessary due to the

  10. Compact planar microwave blocking filters

    NASA Technical Reports Server (NTRS)

    U-Yen, Kongpop (Inventor); Wollack, Edward J. (Inventor)

    2012-01-01

    A compact planar microwave blocking filter includes a dielectric substrate and a plurality of filter unit elements disposed on the substrate. The filter unit elements are interconnected in a symmetrical series cascade with filter unit elements being organized in the series based on physical size. In the filter, a first filter unit element of the plurality of filter unit elements includes a low impedance open-ended line configured to reduce the shunt capacitance of the filter.

  11. Local drinking water filters reduce diarrheal disease in Cambodia: a randomized, controlled trial of the ceramic water purifier.

    PubMed

    Brown, Joe; Sobsey, Mark D; Loomis, Dana

    2008-09-01

    A randomized, controlled intervention trial of two household-scale drinking water filters was conducted in a rural village in Cambodia. After collecting four weeks of baseline data on household water quality, diarrheal disease, and other data related to water use and handling practices, households were randomly assigned to one of three groups of 60 households: those receiving a ceramic water purifier (CWP), those receiving a second filter employing an iron-rich ceramic (CWP-Fe), and a control group receiving no intervention. Households were followed for 18 weeks post-baseline with biweekly follow-up. Households using either filter reported significantly less diarrheal disease during the study compared with a control group of households without filters as indicated by longitudinal prevalence ratios CWP: 0.51 (95% confidence interval [CI]: 0.41-0.63); CWP-Fe: 0.58 (95% CI: 0.47-0.71), an effect that was observed in all age groups and both sexes after controlling for clustering within households and within individuals over time. PMID:18784232

  12. Application of a Reduced Order Kalman Filter to Initialize a Coupled Atmosphere-Ocean Model: Impact on the Prediction of El Nino

    NASA Technical Reports Server (NTRS)

    Ballabrera-Poy, J.; Busalacchi, A.; Murtugudde, R.

    2000-01-01

    A reduced order Kalman Filter, based on a simplification of the Singular Evolutive Extended Kalman (SEEK) filter equations, is used to assimilate observed fields of the surface wind stress, sea surface temperature and sea level into the nonlinear coupled ocean-atmosphere model of Zebiak and Cane. The SEEK filter projects the Kalman Filter equations onto a subspace defined by the eigenvalue decomposition of the error forecast matrix, allowing its application to high dimensional systems. The Zebiak and Cane model couples a linear reduced gravity ocean model with a single vertical mode atmospheric model of Zebiak. The compatibility between the simplified physics of the model and each observed variable is studied separately and together. The results show the ability of the model to represent the simultaneous value of the wind stress, SST and sea level, when the fields are limited to the latitude band 10 deg S - 10 deg N In this first application of the Kalman Filter to a coupled ocean-atmosphere prediction model, the sea level fields are assimilated in terms of the Kelvin and Rossby modes of the thermocline depth anomaly. An estimation of the error of these modes is derived from the projection of an estimation of the sea level error over such modes. This method gives a value of 12 for the error of the Kelvin amplitude, and 6 m of error for the Rossby component of the thermocline depth. The ability of the method to reconstruct the state of the equatorial Pacific and predict its time evolution is demonstrated. The method is shown to be quite robust for predictions up to six months, and able to predict the onset of the 1997 warm event fifteen months before its occurrence.

  13. Application of a Reduced Order Kalman Filter to Initialize a Coupled Atmosphere-Ocean Model: Impact on the Prediction of El Nino

    NASA Technical Reports Server (NTRS)

    Ballabrera-Poy, Joaquim; Busalacchi, Antonio J.; Murtugudde, Ragu

    2000-01-01

    A reduced order Kalman Filter, based on a simplification of the Singular Evolutive Extended Kalman (SEEK) filter equations, is used to assimilate observed fields of the surface wind stress, sea surface temperature and sea level into the nonlinear coupled ocean-atmosphere model. The SEEK filter projects the Kalman Filter equations onto a subspace defined by the eigenvalue decomposition of the error forecast matrix, allowing its application to high dimensional systems. The Zebiak and Cane model couples a linear reduced gravity ocean model with a single vertical mode atmospheric model of Zebiak. The compatibility between the simplified physics of the model and each observed variable is studied separately and together. The results show the ability of the model to represent the simultaneous value of the wind stress, SST and sea level, when the fields are limited to the latitude band 10 deg S - 10 deg N. In this first application of the Kalman Filter to a coupled ocean-atmosphere prediction model, the sea level fields are assimilated in terms of the Kelvin and Rossby modes of the thermocline depth anomaly. An estimation of the error of these modes is derived from the projection of an estimation of the sea level error over such modes. This method gives a value of 12 for the error of the Kelvin amplitude, and 6 m of error for the Rossby component of the thermocline depth. The ability of the method to reconstruct the state of the equatorial Pacific and predict its time evolution is demonstrated. The method is shown to be quite robust for predictions I up to six months, and able to predict the onset of the 1997 warm event fifteen months before its occurrence.

  14. A Single-Phase Current Source Solar Inverter with Constant Instantaneous Power, Improved Reliability, and Reduced-Size DC-Link Filter

    NASA Astrophysics Data System (ADS)

    Bush, Craig R.

    This dissertation presents a novel current source converter topology that is primarily intended for single-phase photovoltaic (PV) applications. In comparison with the existing PV inverter technology, the salient features of the proposed topology are: a) the low frequency (double of line frequency) ripple that is common to single-phase inverters is greatly reduced; b) the absence of low frequency ripple enables significantly reduced size pass components to achieve necessary DC-link stiffness and c) improved maximum power point tracking (MPPT) performance is readily achieved due to the tightened current ripple even with reduced-size passive components. The proposed topology does not utilize any electrolytic capacitors. Instead an inductor is used as the DC-link filter and reliable AC film capacitors are utilized for the filter and auxiliary capacitor. The proposed topology has a life expectancy on par with PV panels. The proposed modulation technique can be used for any current source inverter where an unbalanced three-phase operation is desires such as active filters and power controllers. The proposed topology is ready for the next phase of microgrid and power system controllers in that it accepts reactive power commands. This work presents the proposed topology and its working principle supported by with numerical verifications and hardware results. Conclusions and future work are also presented.

  15. The combination of two novel tobacco blends and filter technologies to reduce the in vitro genotoxicity and cytotoxicity of prototype cigarettes.

    PubMed

    Crooks, Ian; Scott, Ken; Dalrymple, Annette; Dillon, Debbie; Meredith, Clive

    2015-04-01

    Tobacco smoke from a combustible cigarette contains more than 6000 constituents; approximately 150 of these are identified as toxicants. Technologies that modify the tobacco blend to reduce toxicant emissions have been developed. These include tobacco sheet substitute to dilute toxicants in smoke and blend treated tobacco to reduce the levels of nitrogenous precursors and some polyphenols. Filter additives to reduce gas (vapour) phase constituents have also been developed. In this study, both tobacco blend and filter technologies were combined into an experimental cigarette and smoked to International Organisation on Standardisation and Health Canada puffing parameters. The resulting particulate matter was subjected to a battery of in vitro genotoxicity and cytotoxicity assays - the Ames test, mouse lymphoma assay, the in vitro micronucleus test and the Neutral Red Uptake assay. The results indicate that cigarettes containing toxicant reducing technologies may be developed without observing new additional genotoxic hazards as assessed by the assays specified. In addition, reductions in bacterial mutagenicity and mammalian genotoxicity of the experimental cigarette were observed relative to the control cigarettes. There were no significant differences in cytotoxicity relative to the control cigarettes. PMID:25584437

  16. Second-order advantage achieved by modeling excitation-emission fluorescence matrices affected by inner filter effects using a strategy which combines standardization and calibration: reducing experimental and increasing analytical sensitivity.

    PubMed

    Schenone, Agustina V; Culzoni, María J; Galera, María Martínez; Goicoechea, Héctor C

    2013-05-15

    A methodology based on second-order data (excitation emission matrices) modeling with one of most popular algorithms presenting the second-order advantage, parallel factor analysis (PARAFAC), combined with transference of calibration is proposed to predict the analyte concentration when significant inner filter effects occur, even in the presence of unexpected sample components. The quantitation of phenylephrine hydrochloride (PHE) in water samples (concentrations ranged between 250 and 750 ng mL(-1)) in the presence of ibuprofen, acetyl salicylic acid and paracetamol (which produce inner filter effect across the useful wavelength range) was achieved. The strategy allows reducing the experimental work and increasing the analytical sensitivity in the determination of the analyte of interest in the presence of unexpected compounds and matrix effect caused by inner filter, avoiding the preparation of a large number of solutions and maintaining acceptable figures of merit. Recoveries between 97 and 102% for validation and real spiked water samples, respectively, and a relative prediction error of 5% were achieved. Results were compared with those obtained after the application of the classical standard addition method combined with PARAFAC, carrying out five additions to each sample, in triplicate. The presented methodology constitutes a simple and low-cost method for the determination of PHE in water samples with a considerable reduction in standard handling and time. This methodology can be extended to other systems presenting matrix effect and, consequently, can become in a useful tool to know the amount of pharmaceuticals in the aquatic environment and to evaluate the effect of conventional wastewater treatment plants in the elimination of pharmaceutical compounds. PMID:23618146

  17. Comparison of Image Filters for Low Dose Neutron Imaging

    NASA Astrophysics Data System (ADS)

    Hungler, P. C.; Bennett, L. G. I.; Lewis, W. J.; Bevan, G.; Metzler, J.

    Neutron imaging using low flux sources, such as accelerators or low flux nuclear reactors, produces images which contain significant amounts of noise. The noise indications are a result of high energy gamma radiation and some neutron scattering which hit the CCD detector despite heavy shielding. The amount of noise in an image is a factor of the exposure time required to produce images with adequate dynamic ranges. Minimization of noise and maximization of the dynamic range are inversely proportional and the exposure time is often extended to increase incident neutrons at the expense of noise. The resultant noise can be reduced using image filters; however, these filters usually increase the signal to noise ratio (SNR) at the expense of spatial resolution. Three filters were applied to low dose neutron images acquired at RMC; a median filter, a Z-projection filter and a hybrid PDE filter. The median filter and the hybrid PDE filter showed similar performance in 3D with regards to SNR and spatial resolution, however, the median filter created numerous artefacts in the resultant tomogram. The Z-projection filter using 5 projections had the best performance in 2D improving the SNR of the raw image from 10.2 ± 0.767 to 22.5 ± 1.52 and the spatial resolution from 331 ± 2.89 to 309 ± 0.846, respectively. The Z-projection filter was not evaluated in 3D due to facility induced constraints.

  18. Comparison of Different Edge Detections and Noise Reduction on Ultrasound Images of Carotid and Brachial Arteries Using a Speckle Reducing Anisotropic Diffusion Filter

    PubMed Central

    Rafati, Mehravar; Arabfard, Masoud; Rafati-Rahimzadeh, Mehrdad

    2014-01-01

    Background: Common carotid artery (CCA) ultrasound with measurement of intima-media thickness (IMT) is a safe and noninvasive technique for assessing subclinical atherosclerosis and determining cardiovascular risks. Moreover, the pattern of wall thickening in the brachial artery (BA) is rather diffuse compared to the carotid artery and may be a more sensitive indicator of long-term systemic exposure to risk factors. Therefore noninvasive evaluation of mechanical parameters changes of both arteries has gained the attention of researchers. Objectives: The aim of this study was to compare different edge detection techniques with speckle reducing anisotropic diffusion (SRAD) de-noising filter in ultrasound images of both arteries. Patients and Methods: In a cross-sectional design, an examination was performed on ten men with mean age of 40 ± 5 years from September 2012 to March 2013 through random sampling. An ultrasonic examination of the left CCA and BA was performed. The program was designed in the MATLAB software to extract consecutive images in JPEG format from the AVI. Another program was designed in the MATLAB software to apply regions of interest (ROI) on the IMT of the posterior wall of common carotid and brachial arteries. Next, different edge detections and SRAD filter were applied to the ROI, separately. Finally, the program measured mean-squared error (MSE) and peak signal to noise ratio (PSNR). Results: The lowest values of MSE and highest values of PSNR were achieved by Canny edge detection with de-noising SRAD filter for IMT of left CCA and BA in 90 frames. Conclusions: Based on the result, by measuring the MSE and PSNR, this study showed Canny edge detection with SRAD filter is better than other edge detections in terms of speckle suppression and details preservation in CCA and BA ultrasound images. PMID:25593716

  19. Rigid porous filter

    DOEpatents

    Chiang, Ta-Kuan; Straub, Douglas L.; Dennis, Richard A.

    2000-01-01

    The present invention involves a porous rigid filter including a plurality of concentric filtration elements having internal flow passages and forming external flow passages there between. The present invention also involves a pressure vessel containing the filter for the removal of particulates from high pressure particulate containing gases, and further involves a method for using the filter to remove such particulates. The present filter has the advantage of requiring fewer filter elements due to the high surface area-to-volume ratio provided by the filter, requires a reduced pressure vessel size, and exhibits enhanced mechanical design properties, improved cleaning properties, configuration options, modularity and ease of fabrication.

  20. HEPA filter monitoring program

    NASA Astrophysics Data System (ADS)

    Kirchner, K. N.; Johnson, C. M.; Aiken, W. F.; Lucerna, J. J.; Barnett, R. L.; Jensen, R. T.

    1986-07-01

    The testing and replacement of HEPA filters, widely used in the nuclear industry to purify process air, are costly and labor-intensive. Current methods of testing filter performance, such as differential pressure measurement and scanning air monitoring, allow determination of overall filter performance but preclude detection of incipient filter failure such as small holes in the filters. Using current technology, a continual in-situ monitoring system was designed which provides three major improvements over current methods of filter testing and replacement. The improvements include: cost savings by reducing the number of intact filters which are currently being replaced unnecessarily; more accurate and quantitative measurement of filter performance; and reduced personnel exposure to a radioactive environment by automatically performing most testing operations.

  1. Nonlinear optimal semirecursive filtering

    NASA Astrophysics Data System (ADS)

    Daum, Frederick E.

    1996-05-01

    This paper describes a new hybrid approach to filtering, in which part of the filter is recursive but another part in non-recursive. The practical utility of this notion is to reduce computational complexity. In particular, if the non- recursive part of the filter is sufficiently small, then such a filter might be cost-effective to run in real-time with computer technology available now or in the future.

  2. VEP contrast sensitivity responses reveal reduced functional segregation of mid and high filters of visual channels in autism.

    PubMed

    Jemel, Boutheina; Mimeault, Daniel; Saint-Amour, Dave; Hosein, Anthony; Mottron, Laurent

    2010-01-01

    Despite the vast amount of behavioral data showing a pronounced tendency in individuals with autism spectrum disorder (ASD) to process fine visual details, much less is known about the neurophysiological characteristics of spatial vision in ASD. Here, we address this issue by assessing the contrast sensitivity response properties of the early visual-evoked potentials (VEPs) to sine-wave gratings of low, medium and high spatial frequencies in adults with ASD and in an age- and IQ-matched control group. Our results show that while VEP contrast responses to low and high spatial frequency gratings did not differ between ASD and controls, early VEPs to mid spatial frequency gratings exhibited similar response characteristics as those to high spatial frequency gratings in ASD. Our findings show evidence for an altered functional segregation of early visual channels, especially those responsible for processing mid- and high-frequency spatial scales. PMID:20884562

  3. Ceramic filters

    SciTech Connect

    Holmes, B.L.; Janney, M.A.

    1995-12-31

    Filters were formed from ceramic fibers, organic fibers, and a ceramic bond phase using a papermaking technique. The distribution of particulate ceramic bond phase was determined using a model silicon carbide system. As the ceramic fiber increased in length and diameter the distance between particles decreased. The calculated number of particles per area showed good agreement with the observed value. After firing, the papers were characterized using a biaxial load test. The strength of papers was proportional to the amount of bond phase included in the paper. All samples exhibited strain-tolerant behavior.

  4. Eyeglass Filters

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Biomedical Optical Company of America's suntiger lenses eliminate more than 99% of harmful light wavelengths. NASA derived lenses make scenes more vivid in color and also increase the wearer's visual acuity. Distant objects, even on hazy days, appear crisp and clear; mountains seem closer, glare is greatly reduced, clouds stand out. Daytime use protects the retina from bleaching in bright light, thus improving night vision. Filtering helps prevent a variety of eye disorders, in particular cataracts and age related macular degeneration.

  5. Implementation of a reduced order Kalman filter to assimilate ocean color data into a coupled physical-biochemical model of the North Aegean Sea.

    NASA Astrophysics Data System (ADS)

    Kalaroni, Sofia; Tsiaras, Kostas; Economou-Amilli, Athena; Petihakis, George; Politikos, Dimitrios; Triantafyllou, George

    2013-04-01

    Within the framework of the European project OPEC (Operational Ecology), a data assimilation system was implemented to describe chlorophyll-a concentrations of the North Aegean, as well the impact on the European anchovy (Engraulis encrasicolus) biomass distribution provided by a bioenergetics model, related to the density of three low trophic level functional groups of zooplankton (heterotrophic flagellates, microzooplankton and mesozooplankton). The three-dimensional hydrodynamic-biogeochemical model comprises two on-line coupled sub-models: the Princeton Ocean Model (POM) and the European Regional Seas Ecosystem Model (ERSEM). The assimilation scheme is based on the Singular Evolutive Extended Kalman (SEEK) filter and its variant that uses a fixed correction base (SFEK). For the initialization, SEEK filter uses a reduced order error covariance matrix provided by the dominant Empirical Orthogonal Functions (EOF) of model. The assimilation experiments were performed for year 2003 using SeaWiFS chlorophyll-a data during which the physical model uses the atmospheric forcing obtained from the regional climate model HIRHAM5. The assimilation system is validated by assessing the relevance of the system in fitting the data, the impact of the assimilation on non-observed biochemical parameters and the overall quality of the forecasts.

  6. Electrochemical state and internal variables estimation using a reduced-order physics-based model of a lithium-ion cell and an extended Kalman filter

    SciTech Connect

    Stetzel, KD; Aldrich, LL; Trimboli, MS; Plett, GL

    2015-03-15

    This paper addresses the problem of estimating the present value of electrochemical internal variables in a lithium-ion cell in real time, using readily available measurements of cell voltage, current, and temperature. The variables that can be estimated include any desired set of reaction flux and solid and electrolyte potentials and concentrations at any set of one-dimensional spatial locations, in addition to more standard quantities such as state of charge. The method uses an extended Kalman filter along with a one-dimensional physics-based reduced-order model of cell dynamics. Simulations show excellent and robust predictions having dependable error bounds for most internal variables. (C) 2014 Elsevier B.V. All rights reserved.

  7. Stack filters

    NASA Astrophysics Data System (ADS)

    Wendt, P. D.; Coyle, E. J.; Gallagher, N. C., Jr.

    1986-08-01

    A large class of easily implemented nonlinear filters called stack filters are discussed which includes the rank order operators in addition to the compositions of morphological operators. Techniques similar to those used to determine the root signal behavior of median filters are employed to study the convergence properties of the filters, and necessary conditions for a stack filter to preserve monotone regions or edges in signals, and the output distribution of the filters, are obtained. Among the stack filters of window width three are found asymmetric median filters in which one removes only positive going edges, the other removes only negative going edges, while the median filter removes impulses of both signs.

  8. Filters For Chest Radiography

    NASA Astrophysics Data System (ADS)

    Ramanathan, N.; Paron, J.

    1980-08-01

    The objective of low dose radiography is achieved by a judicious combination of proper kV selection, fast film-screen systems and beam filtration. A systematic study of filters was undertaken to evaluate the improvements that can be realized in terms of patient Entrance Skin Exposures (ESE) for chest radiographs. The Picker CD 135 Generator and the Automatic Chest Filmer with dynamic phototiming were used for the study. The kV dependence of ESE with various amounts of zinc and aluminum filtration is presented. The effect of filtration on image contrast is discussed. The variations of ESE with phantom thickness under different filtration conditions are also considered. It was found that the ESE can be reduced by as much as a factor of 1.8 ± .1 with no significant increase in tube loading.

  9. Impact of data assimilation filtering methods on the mesosphere

    NASA Astrophysics Data System (ADS)

    Sankey, David; Ren, Shuzhan; Polavarapu, Saroja; Rochon, Yves J.; Nezlin, Yulia; Beagley, Stephen

    2007-12-01

    Three-dimensional data assimilation schemes typically produce analyses that are not in balance. This is evidenced by the generation of spurious high-frequency waves during the first 2 d of forecasts which start from analyses. To remove these spurious waves, assimilation systems frequently filter analyses before using them in models. This work examines the behavior of various spurious wave filtering methods in the context of a model with a mesosphere. Since gravity waves comprise a significant portion of the mesospheric energy spectrum, it is necessary to retain naturally occurring high-frequency waves while filtering spurious waves. The results show that filtering the full analysis state can remove many important high-frequency oscillations from the mesosphere. On the other hand, filtering analysis increments preserves much more of the natural variability of the model. The incremental analysis updating scheme and the incremental digital filter, which are equivalent for linear models and identical coefficients, are shown to give very similar results in the context of a realistic nonlinear model. Results also show a nonlocal response to the insertion of analysis increments in the troposphere and stratosphere. The global mean temperature in the vicinity of the model lid and the diurnal tidal amplitudes are sensitive to the choice of filtering schemes because the filters reduce the amount of resolved waves available to propagate upward into mesosphere. This sensitivity of the mesosphere to the filtering of the lower atmosphere is exploited to choose an optimal filter for our system using measurements of the mesosphere.

  10. Concentric Split Flow Filter

    NASA Technical Reports Server (NTRS)

    Stapleton, Thomas J. (Inventor)

    2015-01-01

    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  11. A new double FFT-based filter to reduce the effect of 1/f noise spectrum in a tunable diode laser spectrometer (TDLS)

    NASA Astrophysics Data System (ADS)

    Mahdi, Samira; Chen, Youhua; Anderson, Gary

    2013-05-01

    A Tunable diode laser spectrometer (TDLS) system has been designed to scan the near-surface atmosphere for ammonia gas over a wide range of distances (10 m to 1 Km). Since the system is designed for space applications, it needs to be small, lightweight, and low power, which dictates the use of relatively low frequency measurement scans. The spectrometer uses a diode laser, which is subject to a large 1/f noise component at these low frequencies. In this work, digital signal processing techniques are used to maximize the measurement sensitivity of a low frequency TDLS system depending on Double Fast Fourier Transform (DFFT-BF) based- filter. Simulations of the 1/f noise spectrum and ammonia gas absorption peak were performed using a sinusoidal waveform to drive the diode laser. A DFFT-BF-BF method is proposed that reduces the average of the error in the gas readings to nearly 50 percent. Because, this method decreases the effect of 1/f noise while keeping the measurement signal relatively constant.

  12. Towards predictive data-driven simulations of wildfire spread - Part I: Reduced-cost Ensemble Kalman Filter based on a Polynomial Chaos surrogate model for parameter estimation

    NASA Astrophysics Data System (ADS)

    Rochoux, M. C.; Ricci, S.; Lucor, D.; Cuenot, B.; Trouvé, A.

    2014-11-01

    This paper is the first part in a series of two articles and presents a data-driven wildfire simulator for forecasting wildfire spread scenarios, at a reduced computational cost that is consistent with operational systems. The prototype simulator features the following components: an Eulerian front propagation solver FIREFLY that adopts a regional-scale modeling viewpoint, treats wildfires as surface propagating fronts, and uses a description of the local rate of fire spread (ROS) as a function of environmental conditions based on Rothermel's model; a series of airborne-like observations of the fire front positions; and a data assimilation (DA) algorithm based on an ensemble Kalman filter (EnKF) for parameter estimation. This stochastic algorithm partly accounts for the nonlinearities between the input parameters of the semi-empirical ROS model and the fire front position, and is sequentially applied to provide a spatially uniform correction to wind and biomass fuel parameters as observations become available. A wildfire spread simulator combined with an ensemble-based DA algorithm is therefore a promising approach to reduce uncertainties in the forecast position of the fire front and to introduce a paradigm-shift in the wildfire emergency response. In order to reduce the computational cost of the EnKF algorithm, a surrogate model based on a polynomial chaos (PC) expansion is used in place of the forward model FIREFLY in the resulting hybrid PC-EnKF algorithm. The performance of EnKF and PC-EnKF is assessed on synthetically generated simple configurations of fire spread to provide valuable information and insight on the benefits of the PC-EnKF approach, as well as on a controlled grassland fire experiment. The results indicate that the proposed PC-EnKF algorithm features similar performance to the standard EnKF algorithm, but at a much reduced computational cost. In particular, the re-analysis and forecast skills of DA strongly relate to the spatial and temporal

  13. Towards predictive data-driven simulations of wildfire spread - Part I: Reduced-cost Ensemble Kalman Filter based on a Polynomial Chaos surrogate model for parameter estimation

    NASA Astrophysics Data System (ADS)

    Rochoux, M. C.; Ricci, S.; Lucor, D.; Cuenot, B.; Trouvé, A.

    2014-05-01

    This paper is the first part in a series of two articles and presents a data-driven wildfire simulator for forecasting wildfire spread scenarios, at a reduced computational cost that is consistent with operational systems. The prototype simulator features the following components: a level-set-based fire propagation solver FIREFLY that adopts a regional-scale modeling viewpoint, treats wildfires as surface propagating fronts, and uses a description of the local rate of fire spread (ROS) as a function of environmental conditions based on Rothermel's model; a series of airborne-like observations of the fire front positions; and a data assimilation algorithm based on an ensemble Kalman filter (EnKF) for parameter estimation. This stochastic algorithm partly accounts for the non-linearities between the input parameters of the semi-empirical ROS model and the fire front position, and is sequentially applied to provide a spatially-uniform correction to wind and biomass fuel parameters as observations become available. A wildfire spread simulator combined with an ensemble-based data assimilation algorithm is therefore a promising approach to reduce uncertainties in the forecast position of the fire front and to introduce a paradigm-shift in the wildfire emergency response. In order to reduce the computational cost of the EnKF algorithm, a surrogate model based on a polynomial chaos (PC) expansion is used in place of the forward model FIREFLY in the resulting hybrid PC-EnKF algorithm. The performance of EnKF and PC-EnKF is assessed on synthetically-generated simple configurations of fire spread to provide valuable information and insight on the benefits of the PC-EnKF approach as well as on a controlled grassland fire experiment. The results indicate that the proposed PC-EnKF algorithm features similar performance to the standard EnKF algorithm, but at a much reduced computational cost. In particular, the re-analysis and forecast skills of data assimilation strongly relate

  14. Disk filter

    DOEpatents

    Bergman, Werner

    1986-01-01

    An electric disk filter provides a high efficiency at high temperature. A hollow outer filter of fibrous stainless steel forms the ground electrode. A refractory filter material is placed between the outer electrode and the inner electrically isolated high voltage electrode. Air flows through the outer filter surfaces through the electrified refractory filter media and between the high voltage electrodes and is removed from a space in the high voltage electrode.

  15. Disk filter

    DOEpatents

    Bergman, W.

    1985-01-09

    An electric disk filter provides a high efficiency at high temperature. A hollow outer filter of fibrous stainless steel forms the ground electrode. A refractory filter material is placed between the outer electrode and the inner electrically isolated high voltage electrode. Air flows through the outer filter surfaces through the electrified refractory filter media and between the high voltage electrodes and is removed from a space in the high voltage electrode.

  16. Cermet Filters for Diesel Engine Emissions Reduction

    SciTech Connect

    Kong, Peter Chuen Sun

    2001-08-01

    Pollution from diesel engines is a significant part of our nation's air-quality problem. Even under the more stringent standards for heavy-duty engines set to take effect in 2004, these engines will continue to emit large amounts of nitrogen oxides and particulate matter, both of which affect public health. To address this problem, the Idaho National Engineering and Environmental Laboratory (INEEL) invented a self-cleaning, high temperature, cermet filter that reduces heavy-duty diesel engine emissions. The main advantage of the INEEL cermet filter, compared to current technology, is its ability to destroy carbon particles and NOx in diesel engine exhaust. As a result, this technology is expected to improve our nation's environmental quality by meeting the need for heavy-duty diesel engine emissions control. This paper describes the cermet filter technology and the initial research and development effort.

  17. Fabric filter blinding mechanisms

    SciTech Connect

    Notestein, J.E.; Shang, J.Y.

    1982-08-01

    This discussion of various bag/cloth filter degradation mechanisms is mostly common sense. However, this information is occasionally lost in the subtleties of real-system operation. Although this paper is written with reference to fluidized-bed combustion (FBC) applications, the insights are generally applicable. For enumeration of particular filter fabric and baghouse experiences in FBC applications, the reader is referred to a report by Davy McKee Corporatin (no date). A fabric filter is a composite matrix of fibers oriented to retain the dust particles from dust-laden gas. The cleaned gas passes through the fabric filter; the retained dust particles are deposited on the surface of (and within) the fiber matrix. The retained dust can be later removed through mechanical means. The fabric may be made of any fibrous material, spun in yarn, and then woven, impacted, needled, or bonded into a felt. Deep penetration of aggregated fine particles, lack of dust removal during filter cleaning, and chars or condensed aerosols may contribute to the increase in pressure drop across the filter. This increases the filter operation power consumption and, consequently, reduces the filtration capacity. The phenomenon of building a high-pressure drop in spite of filter cleaning provisions is known as blinding. In order to maintain an acceptable gas throughput, blinding problems must be addressed. Recommendations are given: maintain temperature above dew point, use filter aids, by-pass filter during start-up or operational upsets, etc.

  18. Solar Rejection Filter for Large Telescopes

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid; Lesh, James

    2009-01-01

    To reject solar radiation photons at the front aperture for large telescopes, a mosaic of large transmission mode filters is placed in front of the telescope or at the aperture of the dome. Filtering options for effective rejection of sunlight include a smaller filter down-path near the focus of the telescope, and a large-diameter filter located in the front of the main aperture. Two types of large filters are viable: reflectance mode and transmittance mode. In the case of reflectance mode, a dielectric coating on a suitable substrate (e.g. a low-thermal-expansion glass) is arranged to reflect only a single, narrow wavelength and to efficiently transmit all other wavelengths. These coatings are commonly referred to as notch filter. In this case, the large mirror located in front of the telescope aperture reflects the received (signal and background) light into the telescope. In the case of transmittance mode, a dielectric coating on a suitable substrate (glass, sapphire, clear plastic, membrane, and the like) is arranged to transmit only a single wavelength and to reject all other wavelengths (visible and near IR) of light. The substrate of the large filter will determine its mass. At first glance, a large optical filter with a diameter of up to 10 m, located in front of the main aperture, would require a significant thickness to avoid sagging. However, a segmented filter supported by a structurally rugged grid can support smaller filters. The obscuration introduced by the grid is minimal because the total area can be made insignificant. This configuration can be detrimental to a diffraction- limited telescope due to diffraction effects at the edges of each sub-panel. However, no discernable degradation would result for a 20 diffraction-limit telescope (a photon bucket). Even the small amount of sagging in each subpanel should have minimal effect in the performance of a non-diffraction limited telescope because the part has no appreciable optical power. If the

  19. A backtracking algorithm that deals with particle filter degeneracy

    NASA Astrophysics Data System (ADS)

    Baarsma, Rein; Schmitz, Oliver; Karssenberg, Derek

    2016-04-01

    Particle filters are an excellent way to deal with stochastic models incorporating Bayesian data assimilation. While they are computationally demanding, the particle filter has no problem with nonlinearity and it accepts non-Gaussian observational data. In the geoscientific field it is this computational demand that creates a problem, since dynamic grid-based models are often already quite computationally demanding. As such it is of the utmost importance to keep the amount of samples in the filter as small as possible. Small sample populations often lead to filter degeneracy however, especially in models with high stochastic forcing. Filter degeneracy renders the sample population useless, as the population is no longer statistically informative. We have created an algorithm in an existing data assimilation framework that reacts to and deals with filter degeneracy based on Spiller et al. [2008]. During the Bayesian updating step of the standard particle filter, the algorithm tests the sample population for filter degeneracy. If filter degeneracy has occurred, the algorithm resets to the last time the filter did work correctly and recalculates the failed timespan of the filter with an increased sample population. The sample population is then reduced to its original size and the particle filter continues as normal. This algorithm was created in the PCRaster Python framework, an open source tool that enables spatio-temporal forward modelling in Python [Karssenberg et al., 2010] . The framework already contains several data assimilation algorithms, including a standard particle filter and a Kalman filter. The backtracking particle filter algorithm has been added to the framework, which will make it easy to implement in other research. The performance of the backtracking particle filter is tested against a standard particle filter using two models. The first is a simple nonlinear point model, and the second is a more complex geophysical model. The main testing

  20. A Reduced-order Kalman Filter To Assimilate Ssh, Sst and Sss In A Primitive Equation Model of The North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Testut, C. E.; Brasseur, P.; Brankart, J. M.; Verron, J.

    The main objective of this work is to develop an advanced statistical method in order to assimilate, simultaneously, various data sets characterised by low and high resolution, in a model of the North Atlantic Ocean. The assimilated sea surface temperature (SST) data originate from AVHRR observations gathered and processed within the NASA Pathfinder project while the altimetric data consist of sea surface height (SSH) maps computed as the sum of a time-invariant dynamic topography and gridded sea-level anomalies from the AVISO project. In addition, these high resolution data sets (1/4) have been complemented by a low resolution sea-surface salinity (SSS) coming from Levitus 98 monthly climatology. The assimilation system has been implemented in a eddy-permitting OPA configuration which has been elaborated within the framework of the French CLIPPER project and used in the MERCATOR Project for the near-real- time experiment during 2001. The domain of application is the North Atlantic Basin between 20S and 70N with high horizontal resolution (1/3×1/3). The method used in these assimilation experiments is a reduced-order Kalman filter derived from the SEEK, in which the error sub-space is represented by means of a truncated series of Empirical Orthogonal Functions (Eofs) of the system variability. The analysis al- gorithm has been further developed to strengthen the local impact of the data, and to update the forecast error statistics adaptively using all pertinent information left in the innovation vector. Hindcast experiments have been conducted with real observations to reconstruct the Atlantic Ocean circulation between 1992 and 1999. The validation of these experiments with independent in situ measurements (XBT) demonstrates the skill of the system to represent the upper ocean circulation.

  1. Biological Filters.

    ERIC Educational Resources Information Center

    Klemetson, S. L.

    1978-01-01

    Presents the 1978 literature review of wastewater treatment. The review is concerned with biological filters, and it covers: (1) trickling filters; (2) rotating biological contractors; and (3) miscellaneous reactors. A list of 14 references is also presented. (HM)

  2. Metallic Filters

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Filtration technology originated in a mid 1960's NASA study. The results were distributed to the filter industry, an HR Textron responded, using the study as a departure for the development of 421 Filter Media. The HR system is composed of ultrafine steel fibers metallurgically bonded and compressed so that the pore structure is locked in place. The filters are used to filter polyesters, plastics, to remove hydrocarbon streams, etc. Several major companies use the product in chemical applications, pollution control, etc.

  3. FILTER TREATMENT

    DOEpatents

    Sutton, J.B.; Torrey, J.V.P.

    1958-08-26

    A process is described for reconditioning fused alumina filters which have become clogged by the accretion of bismuth phosphate in the filter pores, The method consists in contacting such filters with faming sulfuric acid, and maintaining such contact for a substantial period of time.

  4. Water Filters

    NASA Technical Reports Server (NTRS)

    1987-01-01

    A compact, lightweight electrolytic water filter generates silver ions in concentrations of 50 to 100 parts per billion in the water flow system. Silver ions serve as effective bactericide/deodorizers. Ray Ward requested and received from NASA a technical information package on the Shuttle filter, and used it as basis for his own initial development, a home use filter.

  5. Generic Kalman Filter Software

    NASA Technical Reports Server (NTRS)

    Lisano, Michael E., II; Crues, Edwin Z.

    2005-01-01

    The Generic Kalman Filter (GKF) software provides a standard basis for the development of application-specific Kalman-filter programs. Historically, Kalman filters have been implemented by customized programs that must be written, coded, and debugged anew for each unique application, then tested and tuned with simulated or actual measurement data. Total development times for typical Kalman-filter application programs have ranged from months to weeks. The GKF software can simplify the development process and reduce the development time by eliminating the need to re-create the fundamental implementation of the Kalman filter for each new application. The GKF software is written in the ANSI C programming language. It contains a generic Kalman-filter-development directory that, in turn, contains a code for a generic Kalman filter function; more specifically, it contains a generically designed and generically coded implementation of linear, linearized, and extended Kalman filtering algorithms, including algorithms for state- and covariance-update and -propagation functions. The mathematical theory that underlies the algorithms is well known and has been reported extensively in the open technical literature. Also contained in the directory are a header file that defines generic Kalman-filter data structures and prototype functions and template versions of application-specific subfunction and calling navigation/estimation routine code and headers. Once the user has provided a calling routine and the required application-specific subfunctions, the application-specific Kalman-filter software can be compiled and executed immediately. During execution, the generic Kalman-filter function is called from a higher-level navigation or estimation routine that preprocesses measurement data and post-processes output data. The generic Kalman-filter function uses the aforementioned data structures and five implementation- specific subfunctions, which have been developed by the user on

  6. Hybrid Filter Membrane

    NASA Technical Reports Server (NTRS)

    Laicer, Castro; Rasimick, Brian; Green, Zachary

    2012-01-01

    Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

  7. Multidimensional synthetic estimation filter

    NASA Technical Reports Server (NTRS)

    Monroe, Stanley E., Jr.; Juday, Richard D.

    1990-01-01

    The synthetic estimation filter (SEF) crafts an affine variation into its response to a changing parameter (e.g. scale or rotation). Sets of such filters are used in an estimation correlator to reduce the number of filters required for a given tracking accuracy. By overspecifying the system (one more SEF than parameters to be tracked), the ratio of correlation responses between filters forms a robust estimator into the spanned domain of the parameters. Previous results dealt with a laboratory correlator which could track a single parameter. This paper explores the SEF and the estimator's extension to more dimensions. A 2D example is given in which a reduction of filters from 25 to 3 is demonstrated to span a 4-degree square portion of pose space.

  8. Use of zero-valent iron biosand filters to reduce E. coli O157:H12 in irrigation water applied to spinach plants in a field setting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Zero-valent iron (ZVI) filters may provide an efficient method to mitigate the contamination of produce crops through irrigation water. Purpose: To evaluate the use of ZVI-filtration in decontaminating E. coli O157:H12 in irrigation water and on spinach plants in a small, field-scale...

  9. Developing particulate thin filter using coconut fiber for motor vehicle emission

    NASA Astrophysics Data System (ADS)

    Wardoyo, A. Y. P.; Juswono, U. P.; Riyanto, S.

    2016-03-01

    Amounts of motor vehicles in Indonesia have been recognized a sharply increase from year to year with the increment reaching to 22 % per annum. Meanwhile motor vehicles produce particulate emissions in different sizes with high concentrations depending on type of vehicles, fuels, and engine capacity. Motor Particle emissions are not only to significantly contribute the atmosphric particles but also adverse to human health. In order to reduce the particle emission, it is needed a filter. This study was aimed to develop a thin filter using coconut fiber to reduce particulate emissions for motor vehicles. The filter was made of coconut fibers that were grinded into power and mixed with glues. The filter was tested by the measurements of particle concentrations coming out from the vehicle exhaust directly and the particle concentrations after passing through the filter. The efficiency of the filter was calculated by ratio of the particle concentrations before comming in the filter to the particle conentrations after passing through the filter. The results showed that the efficiency of the filter obtained more than 30 %. The efficiency increases sharply when a number of the filters are arranged paralelly.

  10. A Study of Derivative Filters Using the Discrete Fourier Transform. Final Report M. S. Thesis

    NASA Technical Reports Server (NTRS)

    Ioup, G. E.

    1980-01-01

    Important properties of derivative (difference) filters using the discrete Fourier transform are investigated. The filters are designed using the derivative theorem of Fourier analysis. Because physical data are generally degraded by noise, the derivative filter is modified to diminish the effects of the noise, especially the noise amplification which normally occurs while differencing. The basis for these modifications is the reduction of those Fourier components for which the noise most dominates the data. The various filters are tested by applying them to find differences of two-dimensional data to which various amounts of signal dependent noise, as measured by a root mean square value, have been added. The modifications, circular and square ideal low-pass filters and a cut-off pyramid filter, are all found to reduce noise in the derivative without significantly degrading the result.

  11. Anti-Glare Filters

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Glare from CRT screens has been blamed for blurred vision, eyestrain, headaches, etc. Optical Coating Laboratory, Inc. (OCLI) manufactures a coating to reduce glare which was used to coat the windows on the Gemini and Apollo spacecraft. In addition, OCLI offers anti-glare filters (Glare Guard) utilizing the same thin film coating technology. The coating minimizes brightness, provides enhanced contrast and improves readability. The filters are OCLI's first consumer product.

  12. Filtering apparatus

    DOEpatents

    Haldipur, Gaurang B.; Dilmore, William J.

    1992-01-01

    A vertical vessel having a lower inlet and an upper outlet enclosure separated by a main horizontal tube sheet. The inlet enclosure receives the flue gas from a boiler of a power system and the outlet enclosure supplies cleaned gas to the turbines. The inlet enclosure contains a plurality of particulate-removing clusters, each having a plurality of filter units. Each filter unit includes a filter clean-gas chamber defined by a plate and a perforated auxiliary tube sheet with filter tubes suspended from each tube sheet and a tube connected to each chamber for passing cleaned gas to the outlet enclosure. The clusters are suspended from the main tube sheet with their filter units extending vertically and the filter tubes passing through the tube sheet and opening in the outlet enclosure. The flue gas is circulated about the outside surfaces of the filter tubes and the particulate is absorbed in the pores of the filter tubes. Pulses to clean the filter tubes are passed through their inner holes through tubes free of bends which are aligned with the tubes that pass the clean gas.

  13. Filtering apparatus

    DOEpatents

    Haldipur, G.B.; Dilmore, W.J.

    1992-09-01

    A vertical vessel is described having a lower inlet and an upper outlet enclosure separated by a main horizontal tube sheet. The inlet enclosure receives the flue gas from a boiler of a power system and the outlet enclosure supplies cleaned gas to the turbines. The inlet enclosure contains a plurality of particulate-removing clusters, each having a plurality of filter units. Each filter unit includes a filter clean-gas chamber defined by a plate and a perforated auxiliary tube sheet with filter tubes suspended from each tube sheet and a tube connected to each chamber for passing cleaned gas to the outlet enclosure. The clusters are suspended from the main tube sheet with their filter units extending vertically and the filter tubes passing through the tube sheet and opening in the outlet enclosure. The flue gas is circulated about the outside surfaces of the filter tubes and the particulate is absorbed in the pores of the filter tubes. Pulses to clean the filter tubes are passed through their inner holes through tubes free of bends which are aligned with the tubes that pass the clean gas. 18 figs.

  14. Diesel exhaust filter-incinerator

    SciTech Connect

    Martyniuk, E.T.

    1981-08-11

    A diesel engine exhaust particulate filter-incinerator comprising an enclosed filter panel having particulate deposition surfaces bordered by electrodes of a high voltage power supply. Periodic incineration is accomplished by the collection on the surfaces of particulates in amounts sufficient to conduct sufficient electric current along paths through the particulates to heat them to incineration temperature. Ignition and burn off of particulates may be automatically accomplished by maintaining a suitable voltage across the electrodes at the edges of the collection surfaces to initiate arc-like current flow before the collected particulates reach a level that would plug the filter. Specific embodiments of exemplary filter constructions are disclosed.

  15. RETENTION OF SULFUR DIOXIDE BY NYLON FILTERS

    EPA Science Inventory

    Based on laboratory studies, recovery efficiencies of sulfur dioxide (SO2) were determined for nylon filters. The nylon filters used in these experiments were found to retain SO2. A relatively uniform amount (1.7%) was recoverable from each nylon filter, independent of relative...

  16. An information theoretic approach of designing sparse kernel adaptive filters.

    PubMed

    Liu, Weifeng; Park, Il; Principe, José C

    2009-12-01

    This paper discusses an information theoretic approach of designing sparse kernel adaptive filters. To determine useful data to be learned and remove redundant ones, a subjective information measure called surprise is introduced. Surprise captures the amount of information a datum contains which is transferable to a learning system. Based on this concept, we propose a systematic sparsification scheme, which can drastically reduce the time and space complexity without harming the performance of kernel adaptive filters. Nonlinear regression, short term chaotic time-series prediction, and long term time-series forecasting examples are presented. PMID:19923047

  17. Optimization of the development process for air sampling filter standards

    NASA Astrophysics Data System (ADS)

    Mena, RaJah Marie

    Air monitoring is an important analysis technique in health physics. However, creating standards which can be used to calibrate detectors used in the analysis of the filters deployed for air monitoring can be challenging. The activity of a standard should be well understood, this includes understanding how the location within the filter affects the final surface emission rate. The purpose of this research is to determine the parameters which most affect uncertainty in an air filter standard and optimize these parameters such that calibrations made with them most accurately reflect the true activity contained inside. A deposition pattern was chosen from literature to provide the best approximation of uniform deposition of material across the filter. Samples sets were created varying the type of radionuclide, amount of activity (high activity at 6.4 -- 306 Bq/filter and one low activity 0.05 -- 6.2 Bq/filter, and filter type. For samples analyzed for gamma or beta contaminants, the standards created with this procedure were deemed sufficient. Additional work is needed to reduce errors to ensure this is a viable procedure especially for alpha contaminants.

  18. Humic acid interference with virus recovery by electropositive microporous filters.

    PubMed Central

    Guttman-Bass, N; Catalano-Sherman, J

    1986-01-01

    The effects of humic acid on poliovirus type 1 recovery from water by Zeta Plus 60S filters were investigated. The humic acid interfered by preventing virus adsorption to the filters, and the interference increased as a function of the amount of humic acid filtered. Humic acid decreased virus adsorption when filtered before the virus, but did not elute virus which had adsorbed to the filters. The effects on virus recovery were not due to alterations in virus titer or neutralizability. The addition of AlCl3, which improved virus recovery by electronegative filters in the presence of humic acid, did not aid in overall virus recovery by the Zeta Plus filters in the presence or absence of humic acid. However, the salt and humic acid in combination improved virus adsorption and concurrently reduced virus elution efficiency. The addition of NaH2PO4 had no direct effect on virus recovery and did not alter the effect of humic acid. In an attempt to identify the components of humic acid responsible for the interference, humic materials were fractionated by size by using Sephadex gel chromatography and dialysis, and the fractions were tested for interfering activity. Interference was not associated with specific size fractions of the humic materials. PMID:3021058

  19. Parallel Subconvolution Filtering Architectures

    NASA Technical Reports Server (NTRS)

    Gray, Andrew A.

    2003-01-01

    These architectures are based on methods of vector processing and the discrete-Fourier-transform/inverse-discrete- Fourier-transform (DFT-IDFT) overlap-and-save method, combined with time-block separation of digital filters into frequency-domain subfilters implemented by use of sub-convolutions. The parallel-processing method implemented in these architectures enables the use of relatively small DFT-IDFT pairs, while filter tap lengths are theoretically unlimited. The size of a DFT-IDFT pair is determined by the desired reduction in processing rate, rather than on the order of the filter that one seeks to implement. The emphasis in this report is on those aspects of the underlying theory and design rules that promote computational efficiency, parallel processing at reduced data rates, and simplification of the designs of very-large-scale integrated (VLSI) circuits needed to implement high-order filters and correlators.

  20. Filter Enhances Fluorescent-Penetrant-Inspecting Borescope

    NASA Technical Reports Server (NTRS)

    Molina, Orlando G.

    1990-01-01

    Slip-on eyepiece for commercial ultraviolet-light borescope reduces both amount of short-wave ultraviolet light that reaches viewer's eye and apparent intensity of unwanted reflections of white light from surfaces undergoing inspection. Fits on stock eyepiece of borescope, which illuminates surface inspected with intense ultraviolet light. Surface, which is treated with fluorescent dye, emits bright-green visible light wherever dye penetrates - in cracks and voids. Eyepiece contains deep-yellow Wratten 15 (G) filter, which attenuates unwanted light strongly but passes yellow-green fluorescence so defects seen clearly.

  1. A real-time recursive filter for the attitude determination of the Spacelab instrument pointing subsystem

    NASA Technical Reports Server (NTRS)

    West, M. E.

    1992-01-01

    A real-time estimation filter which reduces sensitivity to system variations and reduces the amount of preflight computation is developed for the instrument pointing subsystem (IPS). The IPS is a three-axis stabilized platform developed to point various astronomical observation instruments aboard the shuttle. Currently, the IPS utilizes a linearized Kalman filter (LKF), with premission defined gains, to compensate for system drifts and accumulated attitude errors. Since the a priori gains are generated for an expected system, variations result in a suboptimal estimation process. This report compares the performance of three real-time estimation filters with the current LKF implementation. An extended Kalman filter and a second-order Kalman filter are developed to account for the system nonlinearities, while a linear Kalman filter implementation assumes that the nonlinearities are negligible. The performance of each of the four estimation filters are compared with respect to accuracy, stability, settling time, robustness, and computational requirements. It is shown, that for the current IPS pointing requirements, the linear Kalman filter provides improved robustness over the LKF with less computational requirements than the two real-time nonlinear estimation filters.

  2. ROTARY FILTER FINES TESTING FOR SMALL COLUMN ION EXCHANGE

    SciTech Connect

    Herman, D.

    2011-08-03

    SRNL was requested to quantify the amount of 'fines passage' through the 0.5 micron membranes currently used for the rotary microfilter (RMF). Testing was also completed to determine if there is any additional benefit to utilizing a 0.1 micron filter to reduce the amount of fines that could pass through the filter. Quantifying of the amount of fines that passed through the two sets of membranes that were tested was accomplished by analyzing the filtrate by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) for titanium. Even with preparations to isolate the titanium, all samples returned results of less than the instrument's detection limit of 0.184 mg/L. Test results show that the 0.5 micron filters produced a significantly higher flux while showing a negligible difference in filtrate clarity measured by turbidity. The first targeted deployment of the RMF is with the Small Column Ion Exchange (SCIX) at the Savannah River Site (SRS). SCIX uses crystalline silicotitanate (CST) to sorb cesium to decontaminate a clarified salt solution. The passage of fine particles through the filter membranes in sufficient quantities has the potential to impact the downstream facilities. To determine the amount of fines passage, a contract was established with SpinTek Filtration to operate a 3-disk pilot scale unit with prototypic filter disk and various feeds and two different filter disk membranes. SpinTek evaluated a set of the baseline 0.5 micron filter disks as well as a set of 0.1 micron filter disks to determine the amount of fine particles that would pass the membrane and to determine the flux each set produced. The membrane on both disk sets is manufactured by the Pall Corporation (PMM 050). Each set of disks was run with three feed combinations: prototypically ground CST, CST plus monosodium titanate (MST), and CST, MST, plus Sludge Batch 6 (SB6) simulant. Throughout the testing, samples of the filtrate were collected, measured for turbidity, and sent back

  3. Magnetic bearing stiffness control using frequency band filtering

    NASA Technical Reports Server (NTRS)

    Chen, H. Ming

    1989-01-01

    Active magnetic bearings can be implemented with frequency band-reject filtering that decreases the bearing stiffness and damping at a small bandwidth around a chosen frequency. The control scheme was used for reducing a rotor dynamic force, such as an imbalance force, transmitted to the bearing stator. The scheme creates additional system vibration modes at the same frequency. It also shows that the amount of force reduction is limited by the stability requirement of these modes.

  4. Digital filtering for data compression in telemetry systems

    SciTech Connect

    Bell, R.M.

    1994-08-01

    There are many obstacles to using data compression in a telemetry system. Non-linear quantization is often too lossy, and the data is too highly structured to make variable-length entropy codes practical. This paper describes a lossless telemetry data compression system that was built using digital FIR filters. The method of compression takes advantage of the fact that the optimal Nyquist sampling rate is rarely achievable due to two factors: (1) Sensor/transducers are not bandlimited to the frequencies of interest, and (2) Accurate, high-order analog filters are not available to perform effective band limiting and prevent aliasing. Real-time digital filtering can enhance the performance of a typical sampling system so that it approaches Nyquist sampling rates, effectively compressing the amount of data and reducing transmission bandwidth. The system that was built reduced the sampling rate of 14 high-frequency vibration channels by a factor of two, and reduced the bandwidth of the-data link from 1.8 Mbps to 1.28 Mbps. The entire circuit uses seven function-specific, digital-filter DSP`s operating in parallel (two 128-tap FIR filters can be implemented on each Motorola DSP56200), one EPROM and a Programmable Logic Device as the controller.

  5. Tracking Comb Filter Suppresses Welder Harmonics

    NASA Technical Reports Server (NTRS)

    Delcher, Ray C.

    1992-01-01

    Tracking comb filter includes charge-coupled-device delay line and phase-locked loop. Filter removes harmonics of frequency of repetition of welding-current pulses from acoustic-emission signal. Spurious signals reduced almost to fundamental limit.

  6. BMP FILTERS: UPFLOW VS. DOWNFLOW

    EPA Science Inventory

    Filtration methods have been found to be effective in reducing pollutant levels in stormwater. The main drawback of these methods is that the filters get clogged frequently and require periodical maintenance. In stormwater treatment, because of the cost of pumping, the filters ar...

  7. Amplification of trace amounts of nucleic acids

    DOEpatents

    Church, George M.; Zhang, Kun

    2008-06-17

    Methods of reducing background during amplification of small amounts of nucleic acids employ careful analysis of sources of low level contamination. Ultraviolet light can be used to reduce nucleic acid contaminants in reagents and equipment. "Primer-dimer" background can be reduced by judicious design of primers. We have shown clean signal-to-noise with as little as starting material as one single human cell (.about.6 picogram), E. coli cell (.about.5 femtogram) or Prochlorococcus cell (.about.3 femtogram).

  8. Water Filters

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Seeking to find a more effective method of filtering potable water that was highly contaminated, Mike Pedersen, founder of Western Water International, learned that NASA had conducted extensive research in methods of purifying water on board manned spacecraft. The key is Aquaspace Compound, a proprietary WWI formula that scientifically blends various types of glandular activated charcoal with other active and inert ingredients. Aquaspace systems remove some substances; chlorine, by atomic adsorption, other types of organic chemicals by mechanical filtration and still others by catalytic reaction. Aquaspace filters are finding wide acceptance in industrial, commercial, residential and recreational applications in the U.S. and abroad.

  9. Application of Archimedes Filter for Reduction of Hanford HLW

    SciTech Connect

    Gilleland, J.; Agnew, S.; Cluggish, B.; Freeman, R.; Miller, R.; Putvinski, S.; Sevier, L.; Umstadter, K.

    2002-02-26

    Archimedes Technology Group, Inc., is developing a plasma mass separator called the Archimedes Filter that separates waste oxide mixtures ion by ion into two mass groups: light and heavy. For the first time, it is feasible to separate large amounts of material atom by atom in a single pass device. Although vacuum ion based electromagnetic separations have been around for many decades, they have traditionally depended on ion beam manipulation. Neutral plasma devices, on the other hand, are much easier, less costly, and permit several orders of magnitude greater throughput. The Filter has many potential applications in areas where separation of species is otherwise difficult or expensive. In particular, radioactive waste sludges at Hanford have been a particularly difficult issue for pretreatment and immobilization. Over 75% of Hanford HLW oxide mass (excluding water, carbon, and nitrogen) has mass less than 59 g/mol. On the other hand, 99.9% of radionuclide activity has mass greater than 89 g/mol. Therefore, Filter mass separation tuned to this cutoff would have a dramatic effect on the amount of IHLW produced--in fact IHLW would be reduced by a factor of at least four. The Archimedes Filter is a brand new tool for the separations specialist's toolbox. In this paper, we show results that describe the extent to which the Filter separates ionized material. Such results provide estimates for the potential advantages of Filter tunability, both in cutoff mass (electric and magnetic fields) and in degree of ionization (plasma power). Archimedes is now engaged in design and fabrication of its Demonstration Filter separator and intends on performing a full-scale treatment of Hanford high-level waste surrogates. The status of the Demo project will be described.

  10. Modeling and simulation of ion-filtered inductively coupled plasma using argon plasma

    NASA Astrophysics Data System (ADS)

    Wu, Chao; Wang, Jian; Zhang, Weiwang; Luo, Yi

    2015-03-01

    An ion-filtered inductively coupled plasma (IF-ICP) is proposed to reduce ion bombardment and provide high metastable species density for chemical vapor deposition. Argon plasma, which has simple reaction mechanism, is simulated to show the effects of ion filter. Compared to typical ICP, the maximum density of ions of IF-ICP is lower while that of metastable species is higher. The filter can absorb ions effectively and relatively small amount of metastable species, with the absorption coefficient proportional to its surface area. A proper gap between filter and substrate can achieve more metastable species and less ions on the substrate. The pressure and RF power need to be optimized based on the tradeoff between deposition rate and ion damage. The density of ions on the substrate can be reduced by two orders of magnitude while that of metastable species are maintained in the order of 1017 m-3 under the optimized conditions.

  11. Development of a Methodology to Conduct Usability Evaluation for Hand Tools that May Reduce the Amount of Small Parts that are Dropped During Installation while Processing Space Flight Hardware

    NASA Technical Reports Server (NTRS)

    Miller, Darcy

    2000-01-01

    Foreign object debris (FOD) is an important concern while processing space flight hardware. FOD can be defined as "The debris that is left in or around flight hardware, where it could cause damage to that flight hardware," (United Space Alliance, 2000). Just one small screw left unintentionally in the wrong place could delay a launch schedule while it is retrieved, increase the cost of processing, or cause a potentially fatal accident. At this time, there is not a single solution to help reduce the number of dropped parts such as screws, bolts, nuts, and washers during installation. Most of the effort is currently focused on training employees and on capturing the parts once they are dropped. Advances in ergonomics and hand tool design suggest that a solution may be possible, in the form of specialty hand tools, which secure the small parts while they are being handled. To assist in the development of these new advances, a test methodology was developed to conduct a usability evaluation of hand tools, while performing tasks with risk of creating FOD. The methodology also includes hardware in the form of a testing board and the small parts that can be installed onto the board during a test. The usability of new hand tools was determined based on efficiency and the number of dropped parts. To validate the methodology, participants were tested while performing a task that is representative of the type of work that may be done when processing space flight hardware. Test participants installed small parts using their hands and two commercially available tools. The participants were from three groups: (1) students, (2) engineers / managers and (3) technicians. The test was conducted to evaluate the differences in performance when using the three installation methods, as well as the difference in performance of the three participant groups.

  12. Effect of surfactant washing on enhanced dewatering of fine coal. [Microstructure and porosity of coal filter cakes

    SciTech Connect

    Binkley, T.O.

    1985-01-01

    The final moisture content of fine coal filter cakes in coal preparation plants is determined by the filtration and dewatering process. Washing the coal filter cake with a surfactant solution is a potentially economical technique to reduce the final moisture in a fine coal filter cake. The microscopic structure of the porous coal filter cake determines the relative permeability, porosity and final moisture content of the coal filter cake. An experimental study of washing fine coal filter cakes formed from coal-water slurries was conducted. The effect of surfactants on the structure of fine coal filter cakes and the final moisture of these filter cakes was investigated. The filter cake structure was determined using the Cahn and Fullman section chord method. This micrographic technique of quantitative stereology utilized an optical microscope and an image analyzer to measure particle and pore sizes. The washing phenomena using Triton X-114 and Aerosol-OT was investigated to determine the ability of surfactants to enhance the dewatering of fine coal. A significant reduction in final moisture content was achieved by washing the filter cake with a 100 ppM Aerosol-OT solution. While Triton X-114 can also produce a significant reduction in the final moisture content in a filter cake, the amount of surfactant adsorbed from the wash liquor onto the coal in the filter cake was, however, more than Aerosol-OT. Wash ratios of ten gave optimum results for both types of surfactants. The effects of washing on particle and pore size distributions in the coal filter cake were analyzed by micrographic measurement. The mean size of the particles and pores was used to correlate the washing results. Comparisons were made between double distilled water filter cakes and double distilled water filter cakes washed with either double distilled water or surfactant solutions. Experimental results are discussed. 25 refs., 68 figs., 32 tabs.

  13. Filtering in SPECT Image Reconstruction

    PubMed Central

    Lyra, Maria; Ploussi, Agapi

    2011-01-01

    Single photon emission computed tomography (SPECT) imaging is widely implemented in nuclear medicine as its clinical role in the diagnosis and management of several diseases is, many times, very helpful (e.g., myocardium perfusion imaging). The quality of SPECT images are degraded by several factors such as noise because of the limited number of counts, attenuation, or scatter of photons. Image filtering is necessary to compensate these effects and, therefore, to improve image quality. The goal of filtering in tomographic images is to suppress statistical noise and simultaneously to preserve spatial resolution and contrast. The aim of this work is to describe the most widely used filters in SPECT applications and how these affect the image quality. The choice of the filter type, the cut-off frequency and the order is a major problem in clinical routine. In many clinical cases, information for specific parameters is not provided, and findings cannot be extrapolated to other similar SPECT imaging applications. A literature review for the determination of the mostly used filters in cardiac, brain, bone, liver, kidneys, and thyroid applications is also presented. As resulting from the overview, no filter is perfect, and the selection of the proper filters, most of the times, is done empirically. The standardization of image-processing results may limit the filter types for each SPECT examination to certain few filters and some of their parameters. Standardization, also, helps in reducing image processing time, as the filters and their parameters must be standardised before being put to clinical use. Commercial reconstruction software selections lead to comparable results interdepartmentally. The manufacturers normally supply default filters/parameters, but these may not be relevant in various clinical situations. After proper standardisation, it is possible to use many suitable filters or one optimal filter. PMID:21760768

  14. Electric filter with movable belt electrode

    SciTech Connect

    Bergman, W.

    1982-02-23

    A method and apparatus are disclosed for removing airborne contaminants entrained in a gas or airstream. The apparatus includes an electric filter characterized by a movable endless belt electrode, a grounded electrode, and a filter medium sandwiched therebetween. Inclusion of the movable, endless belt electrode provides the driving force for advancing the filter medium through the filter, and reduces frictional drag on the filter medium, thereby permitting a wide choice of filter medium materials. Additionally, the belt electrode includes a plurality of pleats in order to provide maximum surface area on which to collect airborne contaminants.

  15. Electric filter with movable belt electrode

    DOEpatents

    Bergman, W.

    1983-09-20

    A method and apparatus for removing airborne contaminants entrained in a gas or airstream includes an electric filter characterized by a movable endless belt electrode, a grounded electrode, and a filter medium sandwiched there between. Inclusion of the movable, endless belt electrode provides the driving force for advancing the filter medium through the filter, and reduces frictional drag on the filter medium, thereby permitting a wide choice of filter medium materials. Additionally, the belt electrode includes a plurality of pleats in order to provide maximum surface area on which to collect airborne contaminants. 4 figs.

  16. Electric filter with movable belt electrode

    DOEpatents

    Bergman, Werner

    1983-01-01

    A method and apparatus for removing airborne contaminants entrained in a gas or airstream includes an electric filter characterized by a movable endless belt electrode, a grounded electrode, and a filter medium sandwiched therebetween. Inclusion of the movable, endless belt electrode provides the driving force for advancing the filter medium through the filter, and reduces frictional drag on the filter medium, thereby permitting a wide choice of filter medium materials. Additionally, the belt electrode includes a plurality of pleats in order to provide maximum surface area on which to collect airborne contaminants.

  17. A rigid porous filter and filtration method

    SciTech Connect

    Chiang, Ta-Kuan; Straub, Douglas, Straub L.; Dennis, Richard A.

    1998-12-01

    The present invention involves a porous rigid filter comprising a plurality of concentric filtration elements having internal flow passages and forming external flow passages there between. The present invention also involves a pressure vessel containing the filter for the removal of particulate from high pressure particulate containing gases, and further involves a method for using the filter to remove such particulate. The present filter has the advantage of requiring fewer filter elements due to the high surface area- to-volume ratio provided by the filter, requires a reduced pressure vessel size, and exhibits enhanced mechanical design properties, improved cleaning properties, configuration options, modularity and ease of fabrication.

  18. Fast bilateral filtering using recursive moving sum

    NASA Astrophysics Data System (ADS)

    Igarashi, Masaki; Ikebe, Masayuki; Shimoyama, Sohsuke; Motohisa, Junichi

    We propose a constant-time algorithm for a bilateral filter. Bilateral filter can be converted into the operation of three-dimensional (3D) convolution. By using recursive moving sum, we can reduce the number of calculations needed to construct a pseudo-Gaussian filter. Applying one-dimensional Gaussian filter to the 3D convolution, we achieved a constant-time bilateral filter. We used a 3-GHz CPU without SIMD instructions, or multi-thread operations. We confirmed our proposed bilateral filter to be processed in constant time. In practical conditions, high PSNR values over 40 dB are obtained.

  19. The effects of spatial filtering and artifacts on electrocorticographic signals

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Coon, W. G.; de Pesters, A.; Brunner, P.; Schalk, G.

    2015-10-01

    Objective. Electrocorticographic (ECoG) signals contain noise that is common to all channels and noise that is specific to individual channels. Most published ECoG studies use common average reference (CAR) spatial filters to remove common noise, but CAR filters may introduce channel-specific noise into other channels. To address this concern, scientists often remove artifactual channels prior to data analysis. However, removing these channels depends on expert-based labeling and may also discard useful data. Thus, the effects of spatial filtering and artifacts on ECoG signals have been largely unknown. This study aims to quantify these effects and thereby address this gap in knowledge. Approach. In this study, we address these issues by exploring the effects of application of two types of unsupervised spatial filters and three methods of detecting signal artifacts using a large ECoG data set (20 subjects, four task conditions in each subject). Main results. Our results confirm that spatial filtering improves performance, i.e., it reduces ECoG signal variance that is not related to the task. They also show that removing artifactual channels automatically (using quantitatively defined rejection criteria) or manually (using expert opinion) does not increase the total amount of task-related information, but does avoid potential contamination from one or more noisy channels. Finally, applying a novel ‘median average reference’ filter does not require the elimination of artifactual channels prior to spatial filtering and still mitigates the influence of channels with channel-specific noise. Thus, it allows the investigator to retain more potentially useful task-related data. Significance. In summary, our results show that appropriately designed spatial filters that account for both common noise and channel-specific noise greatly improve the quality of ECoG signal analyses, and that artifacts in only a single channel can result in profound and undesired effects on

  20. Water Filter

    NASA Technical Reports Server (NTRS)

    1982-01-01

    A compact, lightweight electrolytic water sterilizer available through Ambassador Marketing, generates silver ions in concentrations of 50 to 100 parts per billion in water flow system. The silver ions serve as an effective bactericide/deodorizer. Tap water passes through filtering element of silver that has been chemically plated onto activated carbon. The silver inhibits bacterial growth and the activated carbon removes objectionable tastes and odors caused by addition of chlorine and other chemicals in municipal water supply. The three models available are a kitchen unit, a "Tourister" unit for portable use while traveling and a refrigerator unit that attaches to the ice cube water line. A filter will treat 5,000 to 10,000 gallons of water.

  1. FILTER CAKE REDEPOSITION IN A PULSE-JET FILTER

    EPA Science Inventory

    The report gives results of a pilot-scale study of pulse-jet filter cleaning, a process that is ineffective to the extent that collected dust redeposits, rather than falling to the hopper. Dust tracer techniques were used to measure the amount of redeposition. A mathematical mode...

  2. [Discussion on acupuncture treatment amount].

    PubMed

    Wu, Song; Liang, Fengxia; Wang, Hua; Li, Jia

    2015-05-01

    The amount of acupuncture treatment refers to the sum of acupuncture effects during the treatment. From the factors that constitutes the amount of acupuncture treatment, including the numbers of needling, the size of acupuncture instruments, the depth of acupuncture, the manipulation, the retained time of needle, etc., and combined with teaching and clinical experience, it is believed that the amount of acupuncture treatment is closely related with clinical efficacy, besides, moderate amount of acupuncture treatment is a key factor to improve acupuncture efficacy and guarantee the safety of acupuncture. The basic principles of regular treatment amount are arrival of qi and being moderate, indicating the retained time of needle, treatment frequency and course should be based on individual condition, time, location and disease. PMID:26255521

  3. Robust scale-space filter using second-order partial differential equations.

    PubMed

    Ham, Bumsub; Min, Dongbo; Sohn, Kwanghoon

    2012-09-01

    This paper describes a robust scale-space filter that adaptively changes the amount of flux according to the local topology of the neighborhood. In a manner similar to modeling heat or temperature flow in physics, the robust scale-space filter is derived by coupling Fick's law with a generalized continuity equation in which the source or sink is modeled via a specific heat capacity. The filter plays an essential part in two aspects. First, an evolution step size is adaptively scaled according to the local structure, enabling the proposed filter to be numerically stable. Second, the influence of outliers is reduced by adaptively compensating for the incoming flux. We show that classical diffusion methods represent special cases of the proposed filter. By analyzing the stability condition of the proposed filter, we also verify that its evolution step size in an explicit scheme is larger than that of the diffusion methods. The proposed filter also satisfies the maximum principle in the same manner as the diffusion. Our experimental results show that the proposed filter is less sensitive to the evolution step size, as well as more robust to various outliers, such as Gaussian noise, impulsive noise, or a combination of the two. PMID:22652189

  4. Objects tracking with adaptive correlation filters and Kalman filtering

    NASA Astrophysics Data System (ADS)

    Ontiveros-Gallardo, Sergio E.; Kober, Vitaly

    2015-09-01

    Object tracking is commonly used for applications such as video surveillance, motion based recognition, and vehicle navigation. In this work, a tracking system using adaptive correlation filters and robust Kalman prediction of target locations is proposed. Tracking is performed by means of multiple object detections in reduced frame areas. A bank of filters is designed from multiple views of a target using synthetic discriminant functions. An adaptive approach is used to improve discrimination capability of the synthesized filters adapting them to multiple types of backgrounds. With the help of computer simulation, the performance of the proposed algorithm is evaluated in terms of detection efficiency and accuracy of object tracking.

  5. NUCLEAR RADIATION DOSIMETER USING COMPOSITE FILTER AND A SINGLE ELEMENT FILTER

    DOEpatents

    Storm, E.; Shlaer, S.

    1964-04-21

    A nuclear radiation dosimeter is described that uses, in combination, a composite filter and a single element filter. The composite filter contains a plurality of comminuted metals having K-edges evenly distributed over the energy range of interest and the quantity of each of the metals is selected to result in filtering in an amount inversely proportional to the sensitivity of the film in the range over l00 kev. A copper filter is used that has a thickness to contribute the necessary additional correction in the interval between 40 and 100 kev. (AEC)

  6. Crater detection by linear filters representing the Hough Transform

    NASA Astrophysics Data System (ADS)

    Jahn, Herbert

    1994-08-01

    Crater detection is accomplished by means of Hough transform, applied to binary images, which is obtained by edge detection and thresholding from grey value images. Because the ordinary Hough transform is very time consuming, the problem must be reduced. Starting from minimum mean square estimation linear (matched) filters are obtained representing the radon transform, which is equivalent to the Hough transform. Because the filter coefficients can be calculated in advance and may be saved in a filter bank, the computation of the Hough accumulator array can be speeded up considerably. The computational amount can be reduced further, if the accumulator array is projected from the (a,b,r)-space to the (a,b)-space. In order to do that, a special method is presented, which uses a priori information about the possible circle (or crater) radii. Coarse estimation of the circle center coordinates by this method defines limited regions where the full Hough transform can be applied with a much lower amount of computation. The method presented here was applied to simulated images and to Mars images obtained by the VIKING Mars orbiters.

  7. Adaptable Iterative and Recursive Kalman Filter Schemes

    NASA Technical Reports Server (NTRS)

    Zanetti, Renato

    2014-01-01

    Nonlinear filters are often very computationally expensive and usually not suitable for real-time applications. Real-time navigation algorithms are typically based on linear estimators, such as the extended Kalman filter (EKF) and, to a much lesser extent, the unscented Kalman filter. The Iterated Kalman filter (IKF) and the Recursive Update Filter (RUF) are two algorithms that reduce the consequences of the linearization assumption of the EKF by performing N updates for each new measurement, where N is the number of recursions, a tuning parameter. This paper introduces an adaptable RUF algorithm to calculate N on the go, a similar technique can be used for the IKF as well.

  8. Performance of ceramic membrane filters

    SciTech Connect

    Ahluwalia, R.K.; Im, K.H.; Geyer, H.K.; Shelleman, D.L.; Tressler, R.E.

    1996-08-01

    CeraMem Corp.`s ceramic-membrane coated, dead-end ceramic filters offer a promising alternative to ceramic candle filters providing long-term operational and reliability issues are resolved: regenerability of filter passages by back pulse cleaning, tolerance to alkali-containing combustion gas and thermal/chemical aging. ANL is responsible for analytical modeling of filtration and pulse cleaning operations, flow-through testing, and prediction of filter response to thermal cycling under realistic service conditions. A test apparatus was built to expose ceramic filter specimens to chemical environments simulating operation of pressurized fluidized bed and integrated gasification combined cycle plants. Four long-duration tests have been conducted in which 100-cpsi channel filters were exposed to ash collected downstream of the cyclone separator at the PFBC plant at Tidd. Results are discussed. Focus has now shifted to exposing the advanced candle filter specimens to reducing gas environments containing NaCl, H{sub 2}S, H{sub 2}O, and gasification ash.

  9. Structural evaluation of phospholipidic nanovesicles containing small amounts of chitosan.

    PubMed

    Mertins, Omar; Cardoso, Mateus Borba; Pohlmann, Adriana Raffin; da Silveira, Nádya Pesce

    2006-08-01

    In this study we present a full characterization of nanovesicles containing soybean phosphatidylcholine and polysaccharide chitosan. The nanovesicles were prepared by the reverse phase evaporation method, including the preparation of reverse micelles followed by the formation of an organogel, which is dispersed in water to yield the final liposomal particles. Structural changes as a function of the chitosan amount and the filter porosity used in the nanovesicles preparation were studied employing Static and Dynamic Light Scattering as well as Small Angle X-ray Scattering. The hydrodynamic radius of the nanovesicles ranged between 106 and 287 nm, depending on the chitosan contents and the filter porosity. A comparison with nanovesicles free of chitosan indicates the existence of higher contents of multilamellar structures that depends on the chitosan concentration in the vesicles containing chitosan. Typical spherical vesicles having nanometric diameters with polydispersity mostly desired in the biomedical area could only be achieved by filtration through a 0.45 microm porous filter. PMID:17037851

  10. Filling schemes at submicron scale: Development of submicron sized plasmonic colour filters

    NASA Astrophysics Data System (ADS)

    Rajasekharan, Ranjith; Balaur, Eugeniu; Minovich, Alexander; Collins, Sean; James, Timothy D.; Djalalian-Assl, Amir; Ganesan, Kumaravelu; Tomljenovic-Hanic, Snjezana; Kandasamy, Sasikaran; Skafidas, Efstratios; Neshev, Dragomir N.; Mulvaney, Paul; Roberts, Ann; Prawer, Steven

    2014-09-01

    The pixel size imposes a fundamental limit on the amount of information that can be displayed or recorded on a sensor. Thus, there is strong motivation to reduce the pixel size down to the nanometre scale. Nanometre colour pixels cannot be fabricated by simply downscaling current pixels due to colour cross talk and diffraction caused by dyes or pigments used as colour filters. Colour filters based on plasmonic effects can overcome these difficulties. Although different plasmonic colour filters have been demonstrated at the micron scale, there have been no attempts so far to reduce the filter size to the submicron scale. Here, we present for the first time a submicron plasmonic colour filter design together with a new challenge - pixel boundary errors at the submicron scale. We present simple but powerful filling schemes to produce submicron colour filters, which are free from pixel boundary errors and colour cross- talk, are polarization independent and angle insensitive, and based on LCD compatible aluminium technology. These results lay the basis for the development of submicron pixels in displays, RGB-spatial light modulators, liquid crystal over silicon, Google glasses and pico-projectors.

  11. Filling schemes at submicron scale: Development of submicron sized plasmonic colour filters

    PubMed Central

    Rajasekharan, Ranjith; Balaur, Eugeniu; Minovich, Alexander; Collins, Sean; James, Timothy D.; Djalalian-Assl, Amir; Ganesan, Kumaravelu; Tomljenovic-Hanic, Snjezana; Kandasamy, Sasikaran; Skafidas, Efstratios; Neshev, Dragomir N.; Mulvaney, Paul; Roberts, Ann; Prawer, Steven

    2014-01-01

    The pixel size imposes a fundamental limit on the amount of information that can be displayed or recorded on a sensor. Thus, there is strong motivation to reduce the pixel size down to the nanometre scale. Nanometre colour pixels cannot be fabricated by simply downscaling current pixels due to colour cross talk and diffraction caused by dyes or pigments used as colour filters. Colour filters based on plasmonic effects can overcome these difficulties. Although different plasmonic colour filters have been demonstrated at the micron scale, there have been no attempts so far to reduce the filter size to the submicron scale. Here, we present for the first time a submicron plasmonic colour filter design together with a new challenge - pixel boundary errors at the submicron scale. We present simple but powerful filling schemes to produce submicron colour filters, which are free from pixel boundary errors and colour cross- talk, are polarization independent and angle insensitive, and based on LCD compatible aluminium technology. These results lay the basis for the development of submicron pixels in displays, RGB-spatial light modulators, liquid crystal over silicon, Google glasses and pico-projectors. PMID:25242695

  12. Zeolite - A Natural Filter Material for Lead Polluted Water

    NASA Astrophysics Data System (ADS)

    Neamţu, Corina Ioana; Pică, Elena Maria; Rusu, Tiberiu

    2014-11-01

    Reducing the concentration of lead ions in a wastewater using zeolite has proven to be a successful water treatement method, all over the world. Putting the two media (solid and liquid) in contact in static conditions had good results regarding the concentration of the filtered solution, the pH and the electric conductivity, depending on the values of certain parameters such as the amount of the zeolite, volume of the solution or interaction time. The present study highlights the zeolite ability to retain the lead ions from a solution, in dynamic interaction conditions between the two environments, in a short interaction time. The results confirmed the effectiveness of ion exchange water treatment method in the conditions set, emphasizing once again the properties of the filter material - the zeolite

  13. Design and application of finite impulse response digital filters.

    PubMed

    Miller, T R; Sampathkumaran, K S

    1982-01-01

    The finite impulse response (FIR) digital filter is a spatial domain filter with a frequency domain representation. The theory of the FIR filter is presented and techniques are described for designing FIR filters with known frequency response characteristics. Rational design principles are emphasized based on characterization of the imaging system using the modulation transfer function and physical properties of the imaged objects. Bandpass, Wiener, and low-pass filters were designed and applied to 201Tl myocardial images. The bandpass filter eliminates low-frequency image components that represent background activity and high-frequency components due to noise. The Wiener, or minimum mean square error filter 'sharpens' the image while also reducing noise. The Wiener filter illustrates the power of the FIR technique to design filters with any desired frequency response. The low-pass filter, while of relative limited use, is presented to compare it with a popular elementary 'smoothing' filter. PMID:7060600

  14. A New Method to Cancel RFI---The Adaptive Filter

    NASA Astrophysics Data System (ADS)

    Bradley, R.; Barnbaum, C.

    1996-12-01

    An increasing amount of precious radio frequency spectrum in the VHF, UHF, and microwave bands is being utilized each year to support new commercial and military ventures, and all have the potential to interfere with radio astronomy observations. Some radio spectral lines of astronomical interest occur outside the protected radio astronomy bands and are unobservable due to heavy interference. Conventional approaches to deal with RFI include legislation, notch filters, RF shielding, and post-processing techniques. Although these techniques are somewhat successful, each suffers from insufficient interference cancellation. One concept of interference excision that has not been used before in radio astronomy is adaptive interference cancellation. The concept of adaptive interference canceling was first introduced in the mid-1970s as a way to reduce unwanted noise in low frequency (audio) systems. Examples of such systems include the canceling of maternal ECG in fetal electrocardiography and the reduction of engine noise in the passenger compartment of automobiles. Only recently have high-speed digital filter chips made adaptive filtering possible in a bandwidth as large a few megahertz, finally opening the door to astronomical uses. The system consists of two receivers: the main beam of the radio telescope receives the desired signal corrupted by RFI coming in the sidelobes, and the reference antenna receives only the RFI. The reference antenna is processed using a digital adaptive filter and then subtracted from the signal in the main beam, thus producing the system output. The weights of the digital filter are adjusted by way of an algorithm that minimizes, in a least-squares sense, the power output of the system. Through an adaptive-iterative process, the interference canceler will lock onto the RFI and the filter will adjust itself to minimize the effect of the RFI at the system output. We are building a prototype 100 MHz receiver and will measure the cancellation

  15. Bragg reflection transmission filters for variable resolution monochromators

    SciTech Connect

    Chapman, D. )

    1989-01-01

    There are various methods for improving the angular and spectral resolution of monochromator and analyzer systems. The novel system described here, though limited to higher x-ray energies (>20keV), is based on a dynamical effect occurring on the transmitted beam with a thin perfect crystal plate set in the Bragg reflection case. In the case of Bragg reflection from a perfect crystal, the incident beam is rapidly attenuated as it penetrates the crystal in the range of reflection. This extinction length is of the order of microns. The attenuation length, which determines the amount of normal transmission through the plate is generally much longer. Thus, in the range of the Bragg reflection the attenuation of the transmitted beam can change by several orders of magnitude with a small change in energy or angle. This thin crystal plate cuts a notch in the transmitted beam with a width equal to its Darwin width, thus acting as a transmission filter. When used in a non-dispersive mode with other monochromator crystals, the filter when set at the Bragg angle will reflect the entire Darwin width of the incident beam and transmit the wings of the incident beam distribution. When the element is offset in angle by some fraction of the Darwin width, the filter becomes useful in adjusting the angular width of the transmitted beam and removing a wing. Used in pairs with a symmetric offset, the filters can be used to continuously adjust the intrinsic angular divergence of the beam with good wing reduction. Instances where such filters may be useful are in improving the angular resolution of a small angle scattering camera. These filters may be added to a Bonse-Hart camera with one pair on the incident beam to reduce the intrinsic beam divergence and a second pair on the analyzer arm to improve the analyzer resolution. 2 refs., 3 Figs.

  16. Pixelated filters for spatial imaging

    NASA Astrophysics Data System (ADS)

    Mathieu, Karine; Lequime, Michel; Lumeau, Julien; Abel-Tiberini, Laetitia; Savin De Larclause, Isabelle; Berthon, Jacques

    2015-10-01

    Small satellites are often used by spatial agencies to meet scientific spatial mission requirements. Their payloads are composed of various instruments collecting an increasing amount of data, as well as respecting the growing constraints relative to volume and mass; So small-sized integrated camera have taken a favored place among these instruments. To ensure scene specific color information sensing, pixelated filters seem to be more attractive than filter wheels. The work presented here, in collaboration with Institut Fresnel, deals with the manufacturing of this kind of component, based on thin film technologies and photolithography processes. CCD detectors with a pixel pitch about 30 μm were considered. In the configuration where the matrix filters are positioned the closest to the detector, the matrix filters are composed of 2x2 macro pixels (e.g. 4 filters). These 4 filters have a bandwidth about 40 nm and are respectively centered at 550, 700, 770 and 840 nm with a specific rejection rate defined on the visible spectral range [500 - 900 nm]. After an intense design step, 4 thin-film structures have been elaborated with a maximum thickness of 5 μm. A run of tests has allowed us to choose the optimal micro-structuration parameters. The 100x100 matrix filters prototypes have been successfully manufactured with lift-off and ion assisted deposition processes. High spatial and spectral characterization, with a dedicated metrology bench, showed that initial specifications and simulations were globally met. These excellent performances knock down the technological barriers for high-end integrated specific multi spectral imaging.

  17. The Archimedes Plasma Mass Filter

    NASA Astrophysics Data System (ADS)

    Miller, R. L.; Ohkawa, T.; Agnew, S. F.; Cluggish, B. P.; Freeman, R. L.; Gilleland, J.; Putvinski, S.; Sevier, L.; Umstadter, K. R.

    2001-10-01

    Archimedes Technology Group is developing a plasma technology, called the Archimedes Plasma Mass Filter, which can separate a waste mixture ion by ion into mass groups and as such represents a major advance in waste separations technology. The filter is a plasma device employing a magnetic and electric field configuration that acts as a low-mass-pass filter for ions. Ions with mass above a tunable “cutoff mass” are expelled from the plasma. The Archimedes Plasma Mass Filter satisfies all of the requirements of an economic mass separator system: good single-pass separation, acceptable energy cost per ion, and high material throughput. This technology could significantly reduce the volume of radioactive waste at the Hanford Site in Richland, Washington, which is storing sixty percent of the nation’s defense nuclear waste. The potential waste reduction is dramatic because 82 wtpresently scheduled to be vitrified (immobilized and stored in glass) at Hanford are below mass number 60 while 99.9the radioactivity comes from atoms above mass number 89. We will present the plasma physics basis for the filter effect, the fundamental parameter constraints, and modeling results of filter operation.

  18. Advanced distortion-invariant minimum average correlation energy (MACE) filters.

    PubMed

    Casasent, D; Ravichandran, G

    1992-03-10

    The original minimum average correlation energy (MACE) filter is addressed by using a new database (strategic relocatable objects, missile launchers) and including noise performance, depression angle, and resolution effects on the number of training set images that are required. Major attention is given to our new MACE filter algorithms for distortion-invariant pattern recognition: shifted-MACE filters (to suppress large false correlation peaks), minimum variance-MACE filters (for improved noise performance), multiple symbolic encoded filters (to reduce the effect of false correlation peaks), and Gaussian-MACE filters (to improve noise performance and intraclass recognition and reduce the training set size). PMID:20720728

  19. Advanced distortion-invariant minimum average correlation energy (MACE) filters

    NASA Astrophysics Data System (ADS)

    Casasent, David; Ravichandran, Gopalan

    1992-03-01

    The original minimum average correlation energy (MACE) filter is addressed by using a new database (strategic relocatable objects and missile launchers) and including noise performance, depression angle, and resolution effects on the number of training set images that are required. Major attention is given to new MACE filter algorithms for distortion-invariant pattern recognition: shifted-MACE filters to suppress large false correlation peaks, minimum variance-MACE filters for improved noise performance, multiple symbolic encoded filters to reduce the effect of false correlation peaks, and Gaussian-MACE filters to improve noise performance and intraclass recognition and reduce the training set size.

  20. HEPA filter dissolution process

    SciTech Connect

    Brewer, K.N.; Murphy, J.A.

    1992-12-31

    This invention is comprised of a process for dissolution of spent high efficiency particulate air (HEPA) filters and then combining the complexed filter solution with other radioactive wastes prior to calcining the mixed and blended waste feed. The process is an alternate to a prior method of acid leaching the spent filters which is an inefficient method of treating spent HEPA filters for disposal.

  1. Recirculating electric air filter

    DOEpatents

    Bergman, Werner

    1986-01-01

    An electric air filter cartridge has a cylindrical inner high voltage eleode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

  2. Hepa filter dissolution process

    DOEpatents

    Brewer, Ken N.; Murphy, James A.

    1994-01-01

    A process for dissolution of spent high efficiency particulate air (HEPA) filters and then combining the complexed filter solution with other radioactive wastes prior to calcining the mixed and blended waste feed. The process is an alternate to a prior method of acid leaching the spent filters which is an inefficient method of treating spent HEPA filters for disposal.

  3. HEPA filter dissolution process

    DOEpatents

    Brewer, K.N.; Murphy, J.A.

    1994-02-22

    A process is described for dissolution of spent high efficiency particulate air (HEPA) filters and then combining the complexed filter solution with other radioactive wastes prior to calcining the mixed and blended waste feed. The process is an alternate to a prior method of acid leaching the spent filters which is an inefficient method of treating spent HEPA filters for disposal. 4 figures.

  4. Recirculating electric air filter

    DOEpatents

    Bergman, W.

    1985-01-09

    An electric air filter cartridge has a cylindrical inner high voltage electrode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

  5. [Electrostatic air filters for dental practice].

    PubMed

    Iversen, D B; Tolo, K

    1975-12-01

    The filtrering effect of an electrostatic filtrattion equipment (Vortronic mod. 75) for air filtration was examined by sampling the air in a general dental practice by means of a Casella Slit Sampler for Airborne Bacteria (C. F. Casella & Co. Ltd., London). A reception, a sterilization, two treatment chairs and a resting cabinet were seperated by 180 cm high walls in a rectangular room of 33 m2 and with an air volume of approximately 80 m3. The staff including one dentist and one or two assistents worked from 8 a.m. till 4 p.m. with a 30 min. lunch break. A mean of 17 patients visited the practice every day. The electrostatic filter was placed in front of one of the treatment chairs and the slit sampler was, for one period, placed at a distance of 5 m from the filter. In the next period both filter and slit sampler were placed within 140 cm from the treatment chair. The air was sampled at noon and at 4 p.m. Micro-organisms from the air samples were cultured on blood agar by incubation at 37 degrees C for 48 hours. After incubation all colonies visible to the eye were counted. A total of 36 air samples were examined. Without filtration of the air the bacterial contamination amounted to 14 cultivable organisms per ft3 air at noon and 54 organisms per ft3 at 4 p.m. The filtration equipment proved to reduce the air contamination to 6 cultivable organisms per ft3. PMID:1060050

  6. Bacteria/virus filter membrane

    NASA Technical Reports Server (NTRS)

    Lysaght, M. S.; Goodwin, F.; Roebelen, G.

    1977-01-01

    Hollow acrylate fiber membrane that filters bacterial and viral organisms can be used with closed-cycle life-support systems for underwater habitations or laboratories. Membrane also has applications in fields of medicine, gnotobiotics, pharmaceutical production, and industries and research facilities that require sterile water. Device eliminates need for strong chemicals or sterilizing agents, thereby reducing costs.

  7. A method to improve the determination of wave perturbations close to the tropopause by using a digital filter

    NASA Astrophysics Data System (ADS)

    Alexander, P.; de la Torre, A.; Llamedo, P.; Hierro, R.; Schmidt, T.; Haser, A.; Wickert, J.

    2011-09-01

    GPS radio occultation satellite data allowed to analyze in the last decade for the first time a large amount of atmospheric temperature profiles including both the troposphere and the stratosphere all over the globe. Wave amplitude enhancements have been systematically observed around tropopause levels, which are apparently due to artifacts generated by any digital filter used to isolate the wave components from these data. We present a new filtering method which can be equally applied to temperature or refractivity profiles. It was tested with synthetic temperature data based on NCEP reanalyes and observed wave climatologies and it was also statistically validated with GPS radio occultation profiles from the COSMIC mission. The suggested technique significantly reduces artificial enhancements around the tropopause, mainly at low latitudes, where a sharp lapse rate change usually exists. This represents an improvement in comparison to previous applications of standard filters. In addition it would allow the study of longer vertical wavelengths than previously done with other filtering procedures.

  8. Properties of multilayer filters

    NASA Technical Reports Server (NTRS)

    Baumeister, P. W.

    1973-01-01

    New methods were investigated of using optical interference coatings to produce bandpass filters for the spectral region 110 nm to 200 nm. The types of filter are: triple cavity metal dielectric filters; all dielectric reflection filters; and all dielectric Fabry Perot type filters. The latter two types use thorium fluoride and either cryolite films or magnesium fluoride films in the stacks. The optical properties of the thorium fluoride were also measured.

  9. Filter selection based on light source for multispectral imaging

    NASA Astrophysics Data System (ADS)

    Xu, Peng; Xu, Haisong

    2016-07-01

    In multispectral imaging, it is necessary to select a reduced number of filters to balance the imaging efficiency and spectral reflectance recovery accuracy. Due to the combined effect of filters and light source on reflectance recovery, the optimal filters are influenced by the employed light source in the multispectral imaging system. By casting the filter selection as an optimization issue, the selection of optimal filters corresponding to the employed light source proceeds with respect to a set of target samples utilizing one kind of genetic algorithms, regardless of the detailed spectral characteristics of the light source, filters, and sensor. Under three light sources with distinct spectral power distributions, the proposed filter selection method was evaluated on a filter-wheel based multispectral device with a set of interference filters. It was verified that the filters derived by the proposed method achieve better spectral and colorimetric accuracy of reflectance recovery than the conventional one under different light sources.

  10. Range Filtering For Navigation By Satellite

    NASA Technical Reports Server (NTRS)

    Paielli, Russell

    1989-01-01

    Less processing and storage of data needed. Mathematical basis developed for Kalman filtering of sequential measurements of range from single-channel receiver in Global Positioning System (GPS) to each of several navigation satellites. Range filtering involves separate applications of kinematic Kalman tracking filter to measurements of signal from each satellite in use. State vector consists of pseudorange and time derivatives. Main advantages: simplification of tuning and decreases in required amounts of storage and processing of data for navigation in ships, airplanes, and ground vehicles.

  11. A Game Theoretic Fault Detection Filter

    NASA Technical Reports Server (NTRS)

    Chung, Walter H.; Speyer, Jason L.

    1995-01-01

    The fault detection process is modelled as a disturbance attenuation problem. The solution to this problem is found via differential game theory, leading to an H(sub infinity) filter which bounds the transmission of all exogenous signals save the fault to be detected. For a general class of linear systems which includes some time-varying systems, it is shown that this transmission bound can be taken to zero by simultaneously bringing the sensor noise weighting to zero. Thus, in the limit, a complete transmission block can he achieved, making the game filter into a fault detection filter. When we specialize this result to time-invariant system, it is found that the detection filter attained in the limit is identical to the well known Beard-Jones Fault Detection Filter. That is, all fault inputs other than the one to be detected (the "nuisance faults") are restricted to an invariant subspace which is unobservable to a projection on the output. For time-invariant systems, it is also shown that in the limit, the order of the state-space and the game filter can be reduced by factoring out the invariant subspace. The result is a lower dimensional filter which can observe only the fault to be detected. A reduced-order filter can also he generated for time-varying systems, though the computational overhead may be intensive. An example given at the end of the paper demonstrates the effectiveness of the filter as a tool for fault detection and identification.

  12. Improving the treatment efficiency of constructed wetlands with zeolite-containing filter sands.

    PubMed

    Bruch, Ingo; Fritsche, Johannes; Bänninger, Dominik; Alewell, Ulrike; Sendelov, Michael; Hürlimann, Heinz; Hasselbach, Ralf; Alewell, Christine

    2011-01-01

    In this study the physical and chemical properties of three different lava sands used in constructed wetlands for municipal wastewater treatment were investigated. The aim was to identify those properties and mechanisms that render lava sands as highly efficient filter media which could substitute conventional, fluviatile sands. It was shown that although lava sands per se may be suitable filter materials, the presence of zeolite minerals within the lava sands enhances the purification efficiency tremendously. Zeolites not only increase the sorption capacity, but even more important, they are able to absorb water in large amounts, which in turn leads to stronger swelling. The latter reduces hydrological conductivity considerably, resulting in a longer contact time to eliminate pollutants. A simple mineralogical survey of filter materials for the presence of zeolites may render many installations of constructed wetlands successful. PMID:20933388

  13. Binary Matrix Shuffling Filter for Feature Selection in Neuronal Morphology Classification

    PubMed Central

    Sun, Congwei; Dai, Zhijun; Zhang, Hongyan; Li, Lanzhi; Yuan, Zheming

    2015-01-01

    A prerequisite to understand neuronal function and characteristic is to classify neuron correctly. The existing classification techniques are usually based on structural characteristic and employ principal component analysis to reduce feature dimension. In this work, we dedicate to classify neurons based on neuronal morphology. A new feature selection method named binary matrix shuffling filter was used in neuronal morphology classification. This method, coupled with support vector machine for implementation, usually selects a small amount of features for easy interpretation. The reserved features are used to build classification models with support vector classification and another two commonly used classifiers. Compared with referred feature selection methods, the binary matrix shuffling filter showed optimal performance and exhibited broad generalization ability in five random replications of neuron datasets. Besides, the binary matrix shuffling filter was able to distinguish each neuron type from other types correctly; for each neuron type, private features were also obtained. PMID:25893005

  14. Binary matrix shuffling filter for feature selection in neuronal morphology classification.

    PubMed

    Sun, Congwei; Dai, Zhijun; Zhang, Hongyan; Li, Lanzhi; Yuan, Zheming

    2015-01-01

    A prerequisite to understand neuronal function and characteristic is to classify neuron correctly. The existing classification techniques are usually based on structural characteristic and employ principal component analysis to reduce feature dimension. In this work, we dedicate to classify neurons based on neuronal morphology. A new feature selection method named binary matrix shuffling filter was used in neuronal morphology classification. This method, coupled with support vector machine for implementation, usually selects a small amount of features for easy interpretation. The reserved features are used to build classification models with support vector classification and another two commonly used classifiers. Compared with referred feature selection methods, the binary matrix shuffling filter showed optimal performance and exhibited broad generalization ability in five random replications of neuron datasets. Besides, the binary matrix shuffling filter was able to distinguish each neuron type from other types correctly; for each neuron type, private features were also obtained. PMID:25893005

  15. ARRANGEMENT FOR REPLACING FILTERS

    DOEpatents

    Blomgren, R.A.; Bohlin, N.J.C.

    1957-08-27

    An improved filtered air exhaust system which may be continually operated during the replacement of the filters without the escape of unfiltered air is described. This is accomplished by hermetically sealing the box like filter containers in a rectangular tunnel with neoprene covered sponge rubber sealing rings coated with a silicone impregnated pneumatic grease. The tunnel through which the filters are pushed is normal to the exhaust air duct. A number of unused filters are in line behind the filters in use, and are moved by a hydraulic ram so that a fresh filter is positioned in the air duct. The used filter is pushed into a waiting receptacle and is suitably disposed. This device permits a rapid and safe replacement of a radiation contaminated filter without interruption to the normal flow of exhaust air.

  16. [Vena cava filter for prevention of pulmonary embolism].

    PubMed

    Winkler, W B; Slany, J

    1999-11-01

    Vena caval filters in the prevention of pulmonary embolism All currently available caval filters can be implanted percutaneously in local anaesthesia. In the USA the FDA has approved the stainless steel Greenfield filter, the Titanium Greenfield filter, the Bird's Nest filter, the LGM or VenaTech filter and the Simon Nitinol filter. Some other caval filters are commercially available in Europe, but there exist only few clinical trials about them. The Greenfield filter is implanted since the early seventies and the greatest amount of data has been published about it. Standard indications for filter placement are recurrent pulmonary embolism despite adequate anticoagulation, in patients after pulmonary embolectomy, when there is a contraindication to anticoagulation (e.g. fresh surgical wound, active gastrointestinal bleeding, recent haemorrhagic stroke, major trauma,...) and when serious complications occur after thrombolysis or anticoagulation. In patients who suffer from severe cardiopulmonary disease both a caval filter and anticoagulation may be required. Follow-up investigations include plain abdominal radiography and duplex ultrasound, in special cases computed tomography, cavography, magnetic resonance imaging in newer filter types, and intravascular ultrasound. Complications include recurrent pulmonary embolism, caval obstruction, migration, fracture and perforation of filter struts. As clinically relevant complications are rare, in diligently selected cases the patient will benefit from implantation of a caval filter. PMID:10611842

  17. Corrosion resistant filter unit

    SciTech Connect

    Gentry, J.M.

    1992-02-18

    This patent describes a fluid filter assembly adapted for the filtration of corrosive fluid to be injected into a well bore at pressure levels which may exceed 10,000 pounds per square. It comprises: a frame assembly for the mounting of a portion of the fluid filter assembly therein, the frame assembly; filter pods, the plurality of filter pods forming at least two banks of filter pods, each bank having at least two filter pods therein, each bank of the filter pods being supported by one or more the supports of the plurality of supports secured to selected struts of the frame assembly; an inlet manifold to direct the corrosive fluid to the plurality of filter pods, the inlet manifold being interconnected to the banks of filter pods formed by the filter pods whereby flow of the corrosive fluid can be directed to each bank of the filter pods; an outlet manifold to direct the corrosive fluid from the filter pods, the outlet manifold being interconnected to the banks of filter pods formed by the filter pods; a first valve means to control the flow of the corrosive fluid between banks of filter pods formed by the filter pods whereby the flow of the corrosive fluid can be selectively directed to each bank of the filter pods; a second valve means to selectively control the flow of the corrosive fluid between the inlet manifold and the outlet manifold; and union means for interconnecting the filter pods, inlet manifold and outlet manifold, each of the union means including mechanical connection means and internal seal means for isolating the corrosive fluids from the mechanical connection means.

  18. Anisotropic Total Variation Filtering

    SciTech Connect

    Grasmair, Markus; Lenzen, Frank

    2010-12-15

    Total variation regularization and anisotropic filtering have been established as standard methods for image denoising because of their ability to detect and keep prominent edges in the data. Both methods, however, introduce artifacts: In the case of anisotropic filtering, the preservation of edges comes at the cost of the creation of additional structures out of noise; total variation regularization, on the other hand, suffers from the stair-casing effect, which leads to gradual contrast changes in homogeneous objects, especially near curved edges and corners. In order to circumvent these drawbacks, we propose to combine the two regularization techniques. To that end we replace the isotropic TV semi-norm by an anisotropic term that mirrors the directional structure of either the noisy original data or the smoothed image. We provide a detailed existence theory for our regularization method by using the concept of relaxation. The numerical examples concluding the paper show that the proposed introduction of an anisotropy to TV regularization indeed leads to improved denoising: the stair-casing effect is reduced while at the same time the creation of artifacts is suppressed.

  19. Nanoparticle optical notch filters

    NASA Astrophysics Data System (ADS)

    Kasinadhuni, Pradeep Kumar

    Developing novel light blocking products involves the design of a nanoparticle optical notch filter, working on the principle of localized surface plasmon resonance (LSPR). These light blocking products can be used in many applications. One such application is to naturally reduce migraine headaches and light sensitivity. Melanopsin ganglion cells present in the retina of the human eye, connect to the suprachiasmatic nucleus (SCN-the body's clock) in the brain, where they participate in the entrainment of the circadian rhythms. As the Melanopsin ganglion cells are involved in triggering the migraine headaches in photophobic patients, it is necessary to block the part of visible spectrum that activates these cells. It is observed from the action potential spectrum of the ganglion cells that they absorb light ranging from 450-500nm (blue-green part) of the visible spectrum with a λmax (peak sensitivity) of around 480nm (blue line). Currently prescribed for migraine patients is the FL-41 coating, which blocks a broad range of wavelengths, including wavelengths associated with melanopsin absorption. The nanoparticle optical notch filter is designed to block light only at 480nm, hence offering an effective prescription for the treatment of migraine headaches.

  20. Filter type gas sampler with filter consolidation

    DOEpatents

    Miley, Harry S.; Thompson, Robert C.; Hubbard, Charles W.; Perkins, Richard W.

    1997-01-01

    Disclosed is an apparatus for automatically consolidating a filter or, more specifically, an apparatus for drawing a volume of gas through a plurality of sections of a filter, whereafter the sections are subsequently combined for the purpose of simultaneously interrogating the sections to detect the presence of a contaminant.

  1. Filter type gas sampler with filter consolidation

    DOEpatents

    Miley, H.S.; Thompson, R.C.; Hubbard, C.W.; Perkins, R.W.

    1997-03-25

    Disclosed is an apparatus for automatically consolidating a filter or, more specifically, an apparatus for drawing a volume of gas through a plurality of sections of a filter, where after the sections are subsequently combined for the purpose of simultaneously interrogating the sections to detect the presence of a contaminant. 5 figs.

  2. Permeability of filters used for immunoisolation.

    PubMed

    Iwata, H; Morikawa, N; Ikada, Y

    1996-01-01

    Immunoisolation of islets of Langerhans (islets) by their enclosure in a filter to isolate them from the host immune system following implantation is a particularly attractive method for bioartificial pancreas. The filter should have excellent semipermeability so that damaging components of the immune system cannot reach the implanted islets. In addition, oxygen and nutrients should be supplied at a sufficiently high rate to maintain tissue viability. In the present work we conducted in vitro diffusion studies of solutes with various molecular sizes through Nuclepore filters and an XM-50 ultrafilter, which have been preferentially used for immunoisolation. The high permeability of microsolutes was not reduced much by the presence of any filters, implying that oxygen and nutrients could be effectively supplied to living cells by diffusion even if enclosed in a filter. Since the predominant cause of allograft rejection is activation of cellular immunity by T lymphocyte, while humoral immunity including antibodies and complement proteins plays a major role in the rejection of xenografts, requirements for the semipermeability of filters highly depends on the donor of islet tissue. T lymphocytes with a diameter of about 10 microm can permeate through neither Nuclepore nor XM-50 filters because their pore size is less than 2 microm. Therefore all of the filters are anticipated to act as effective immunobarrier for islet allografts. Although the XM-50 ultrafilter and 0.015-microm-diameter Nuclepore filter can sharply fractionate macromolecules in accordance with their size (around 50 kD) in a pressure-driven process such as ultrafiltration, these filters were found to lose the fractionation efficiency of macrosolutes in a concentration-driven process such as diffusion. In other words, neither the Nuclepore filters nor the XM-50 ultrafilter could prevent passage of immunoglobulin G in the diffusion process. This finding suggests that these filters cannot protect xenogeneic

  3. Cordierite silicon nitride filters

    SciTech Connect

    Sawyer, J.; Buchan, B. ); Duiven, R.; Berger, M. ); Cleveland, J.; Ferri, J. )

    1992-02-01

    The objective of this project was to develop a silicon nitride based crossflow filter. This report summarizes the findings and results of the project. The project was phased with Phase I consisting of filter material development and crossflow filter design. Phase II involved filter manufacturing, filter testing under simulated conditions and reporting the results. In Phase I, Cordierite Silicon Nitride (CSN) was developed and tested for permeability and strength. Target values for each of these parameters were established early in the program. The values were met by the material development effort in Phase I. The crossflow filter design effort proceeded by developing a macroscopic design based on required surface area and estimated stresses. Then the thermal and pressure stresses were estimated using finite element analysis. In Phase II of this program, the filter manufacturing technique was developed, and the manufactured filters were tested. The technique developed involved press-bonding extruded tiles to form a filter, producing a monolithic filter after sintering. Filters manufactured using this technique were tested at Acurex and at the Westinghouse Science and Technology Center. The filters did not delaminate during testing and operated and high collection efficiency and good cleanability. Further development in areas of sintering and filter design is recommended.

  4. Bag filters for TPP

    SciTech Connect

    L.V. Chekalov; Yu.I. Gromov; V.V. Chekalov

    2007-05-15

    Cleaning of TPP flue gases with bag filters capable of pulsed regeneration is examined. A new filtering element with a three-dimensional filtering material formed from a needle-broached cloth in which the filtration area, as compared with a conventional smooth bag, is increased by more than two times, is proposed. The design of a new FRMI type of modular filter is also proposed. A standard series of FRMI filters with a filtration area ranging from 800 to 16,000 m{sup 2} is designed for an output more than 1 million m{sub 3}/h of with respect to cleaned gas. The new bag filter permits dry collection of sulfur oxides from waste gases at TPP operating on high-sulfur coals. The design of the filter makes it possible to replace filter elements without taking the entire unit out of service.

  5. Novel Backup Filter Device for Candle Filters

    SciTech Connect

    Bishop, B.; Goldsmith, R.; Dunham, G.; Henderson, A.

    2002-09-18

    The currently preferred means of particulate removal from process or combustion gas generated by advanced coal-based power production processes is filtration with candle filters. However, candle filters have not shown the requisite reliability to be commercially viable for hot gas clean up for either integrated gasifier combined cycle (IGCC) or pressurized fluid bed combustion (PFBC) processes. Even a single candle failure can lead to unacceptable ash breakthrough, which can result in (a) damage to highly sensitive and expensive downstream equipment, (b) unacceptably low system on-stream factor, and (c) unplanned outages. The U.S. Department of Energy (DOE) has recognized the need to have fail-safe devices installed within or downstream from candle filters. In addition to CeraMem, DOE has contracted with Siemens-Westinghouse, the Energy & Environmental Research Center (EERC) at the University of North Dakota, and the Southern Research Institute (SRI) to develop novel fail-safe devices. Siemens-Westinghouse is evaluating honeycomb-based filter devices on the clean-side of the candle filter that can operate up to 870 C. The EERC is developing a highly porous ceramic disk with a sticky yet temperature-stable coating that will trap dust in the event of filter failure. SRI is developing the Full-Flow Mechanical Safeguard Device that provides a positive seal for the candle filter. Operation of the SRI device is triggered by the higher-than-normal gas flow from a broken candle. The CeraMem approach is similar to that of Siemens-Westinghouse and involves the development of honeycomb-based filters that operate on the clean-side of a candle filter. The overall objective of this project is to fabricate and test silicon carbide-based honeycomb failsafe filters for protection of downstream equipment in advanced coal conversion processes. The fail-safe filter, installed directly downstream of a candle filter, should have the capability for stopping essentially all particulate

  6. MST Filterability Tests

    SciTech Connect

    Poirier, M. R.; Burket, P. R.; Duignan, M. R.

    2015-03-12

    The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). The low filter flux through the ARP has limited the rate at which radioactive liquid waste can be treated. Recent filter flux has averaged approximately 5 gallons per minute (gpm). Salt Batch 6 has had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. In addition, at the time the testing started, SRR was assessing the impact of replacing the 0.1 micron filter with a 0.5 micron filter. This report describes testing of MST filterability to investigate the impact of filter pore size and MST particle size on filter flux and testing of filter enhancers to attempt to increase filter flux. The authors constructed a laboratory-scale crossflow filter apparatus with two crossflow filters operating in parallel. One filter was a 0.1 micron Mott sintered SS filter and the other was a 0.5 micron Mott sintered SS filter. The authors also constructed a dead-end filtration apparatus to conduct screening tests with potential filter aids and body feeds, referred to as filter enhancers. The original baseline for ARP was 5.6 M sodium salt solution with a free hydroxide concentration of approximately 1.7 M.3 ARP has been operating with a sodium concentration of approximately 6.4 M and a free hydroxide concentration of approximately 2.5 M. SRNL conducted tests varying the concentration of sodium and free hydroxide to determine whether those changes had a significant effect on filter flux. The feed slurries for the MST filterability tests were composed of simple salts (NaOH, NaNO2, and NaNO3) and MST (0.2 – 4.8 g/L). The feed slurry for the filter enhancer tests contained simulated salt batch 6 supernate, MST, and filter enhancers.

  7. Survey of digital filtering

    NASA Technical Reports Server (NTRS)

    Nagle, H. T., Jr.

    1972-01-01

    A three part survey is made of the state-of-the-art in digital filtering. Part one presents background material including sampled data transformations and the discrete Fourier transform. Part two, digital filter theory, gives an in-depth coverage of filter categories, transfer function synthesis, quantization and other nonlinear errors, filter structures and computer aided design. Part three presents hardware mechanization techniques. Implementations by general purpose, mini-, and special-purpose computers are presented.

  8. Soliton transmission control by super-Gaussian filters

    NASA Astrophysics Data System (ADS)

    Peral, E.; Capmany, J.; Marti, J.

    1996-12-01

    Bandwidth-limited filtering has been proven to overcome certain limitations in soliton transmission systems. We propose super-Gaussian filters instead of Butterworth filter response obtained with conventionally used Fabry-Perot etalons as a method to improve soliton stability and reduce dispersion degradation and theoretically demonstrate their practical implementation in the form of holographic fiber gratings.

  9. Optimal filter parameters for low SNR seismograms as a function of station and event location

    NASA Astrophysics Data System (ADS)

    Leach, Richard R.; Dowla, Farid U.; Schultz, Craig A.

    1999-06-01

    Global seismic monitoring requires deployment of seismic sensors worldwide, in many areas that have not been studied or have few useable recordings. Using events with lower signal-to-noise ratios (SNR) would increase the amount of data from these regions. Lower SNR events can add significant numbers to data sets, but recordings of these events must be carefully filtered. For a given region, conventional methods of filter selection can be quite subjective and may require intensive analysis of many events. To reduce this laborious process, we have developed an automated method to provide optimal filters for low SNR regional or teleseismic events. As seismic signals are often localized in frequency and time with distinct time-frequency characteristics, our method is based on the decomposition of a time series into a set of subsignals, each representing a band with f/Δ f constant (constant Q). The SNR is calculated on the pre-event noise and signal window. The band pass signals with high SNR are used to indicate the cutoff filter limits for the optimized filter. Results indicate a significant improvement in SNR, particularly for low SNR events. The method provides an optimum filter which can be immediately applied to unknown regions. The filtered signals are used to map the seismic frequency response of a region and may provide improvements in travel-time picking, azimuth estimation, regional characterization, and event detection. For example, when an event is detected and a preliminary location is determined, the computer could automatically select optimal filter bands for data from non-reporting stations. Results are shown for a set of low SNR events as well as 379 regional and teleseismic events recorded at stations ABKT, KIV, and ANTO in the Middle East.

  10. Filter service system

    DOEpatents

    Sellers, Cheryl L.; Nordyke, Daniel S.; Crandell, Richard A.; Tomlins, Gregory; Fei, Dong; Panov, Alexander; Lane, William H.; Habeger, Craig F.

    2008-12-09

    According to an exemplary embodiment of the present disclosure, a system for removing matter from a filtering device includes a gas pressurization assembly. An element of the assembly is removably attachable to a first orifice of the filtering device. The system also includes a vacuum source fluidly connected to a second orifice of the filtering device.