The Essential Complexity of Auditory Receptive Fields

PubMed Central

Thorson, Ivar L.; Liénard, Jean; David, Stephen V.

2015-01-01

Encoding properties of sensory neurons are commonly modeled using linear finite impulse response (FIR) filters. For the auditory system, the FIR filter is instantiated in the spectro-temporal receptive field (STRF), often in the framework of the generalized linear model. Despite widespread use of the FIR STRF, numerous formulations for linear filters are possible that require many fewer parameters, potentially permitting more efficient and accurate model estimates. To explore these alternative STRF architectures, we recorded single-unit neural activity from auditory cortex of awake ferrets during presentation of natural sound stimuli. We compared performance of > 1000 linear STRF architectures, evaluating their ability to predict neural responses to a novel natural stimulus. Many were able to outperform the FIR filter. Two basic constraints on the architecture lead to the improved performance: (1) factorization of the STRF matrix into a small number of spectral and temporal filters and (2) low-dimensional parameterization of the factorized filters. The best parameterized model was able to outperform the full FIR filter in both primary and secondary auditory cortex, despite requiring fewer than 30 parameters, about 10% of the number required by the FIR filter. After accounting for noise from finite data sampling, these STRFs were able to explain an average of 40% of A1 response variance. The simpler models permitted more straightforward interpretation of sensory tuning properties. They also showed greater benefit from incorporating nonlinear terms, such as short term plasticity, that provide theoretical advances over the linear model. Architectures that minimize parameter count while maintaining maximum predictive power provide insight into the essential degrees of freedom governing auditory cortical function. They also maximize statistical power available for characterizing additional nonlinear properties that limit current auditory models. PMID:26683490

Derivative information recovery by a selective integration technique

NASA Technical Reports Server (NTRS)

Johnson, M. A.

1974-01-01

A nonlinear stationary homogeneous digital filter DIRSIT (derivative information recovery by a selective integration technique) is investigated. The spectrum of a quasi-linear discrete describing function (DDF) to DIRSIT is obtained by a digital measuring scheme. A finite impulse response (FIR) approximation to the quasi-linearization is then obtained. Finally, DIRSIT is compared with its quasi-linear approximation and with a standard digital differentiating technique. Results indicate the effects of DIRSIT on a wide variety of practical signals.

Digital filtering implementations for the detection of broad spectral features by direct analysis of passive Fourier transform infrared interferograms.

PubMed

Tarumi, Toshiyasu; Small, Gary W; Combs, Roger J; Kroutil, Robert T

2004-04-01

Finite impulse response (FIR) filters and finite impulse response matrix (FIRM) filters are evaluated for use in the detection of volatile organic compounds with wide spectral bands by direct analysis of interferogram data obtained from passive Fourier transform infrared (FT-IR) measurements. Short segments of filtered interferogram points are classified by support vector machines (SVMs) to implement the automated detection of heated plumes of the target analyte, ethanol. The interferograms employed in this study were acquired with a downward-looking passive FT-IR spectrometer mounted on a fixed-wing aircraft. Classifiers are trained with data collected on the ground and subsequently used for the airborne detection. The success of the automated detection depends on the effective removal of background contributions from the interferogram segments. Removing the background signature is complicated when the analyte spectral bands are broad because there is significant overlap between the interferogram representations of the analyte and background. Methods to implement the FIR and FIRM filters while excluding background contributions are explored in this work. When properly optimized, both filtering procedures provide satisfactory classification results for the airborne data. Missed detection rates of 8% or smaller for ethanol and false positive rates of at most 0.8% are realized. The optimization of filter design parameters, the starting interferogram point for filtering, and the length of the interferogram segments used in the pattern recognition is discussed.

Optimized FPGA Implementation of Multi-Rate FIR Filters Through Thread Decomposition

NASA Technical Reports Server (NTRS)

Kobayashi, Kayla N.; He, Yutao; Zheng, Jason X.

2011-01-01

Multi-rate finite impulse response (MRFIR) filters are among the essential signal-processing components in spaceborne instruments where finite impulse response filters are often used to minimize nonlinear group delay and finite precision effects. Cascaded (multistage) designs of MRFIR filters are further used for large rate change ratio in order to lower the required throughput, while simultaneously achieving comparable or better performance than single-stage designs. Traditional representation and implementation of MRFIR employ polyphase decomposition of the original filter structure, whose main purpose is to compute only the needed output at the lowest possible sampling rate. In this innovation, an alternative representation and implementation technique called TD-MRFIR (Thread Decomposition MRFIR) is presented. The basic idea is to decompose MRFIR into output computational threads, in contrast to a structural decomposition of the original filter as done in the polyphase decomposition. A naive implementation of a decimation filter consisting of a full FIR followed by a downsampling stage is very inefficient, as most of the computations performed by the FIR state are discarded through downsampling. In fact, only 1/M of the total computations are useful (M being the decimation factor). Polyphase decomposition provides an alternative view of decimation filters, where the downsampling occurs before the FIR stage, and the outputs are viewed as the sum of M sub-filters with length of N/M taps. Although this approach leads to more efficient filter designs, in general the implementation is not straightforward if the numbers of multipliers need to be minimized. In TD-MRFIR, each thread represents an instance of the finite convolution required to produce a single output of the MRFIR. The filter is thus viewed as a finite collection of concurrent threads. Each of the threads completes when a convolution result (filter output value) is computed, and activated when the first input of the convolution becomes available. Thus, the new threads get spawned at exactly the rate of N/M, where N is the total number of taps, and M is the decimation factor. Existing threads retire at the same rate of N/M. The implementation of an MRFIR is thus transformed into a problem to statically schedule the minimum number of multipliers such that all threads can be completed on time. Solving the static scheduling problem is rather straightforward if one examines the Thread Decomposition Diagram, which is a table-like diagram that has rows representing computation threads and columns representing time. The control logic of the MRFIR can be implemented using simple counters. Instead of decomposing MRFIRs into subfilters as suggested by polyphase decomposition, the thread decomposition diagrams transform the problem into a familiar one of static scheduling, which can be easily solved as the input rate is constant.

Differential Frequency Hopping (DFH) Modulation for Underwater Acoustic Communications and Networking

DTIC Science & Technology

2009-10-09

trains the coefficients c of a finite impulse response (FIR) filter by gradient descent. The coefficients at iteration k + 1 are computed with the update... absorption . Figure 9 shows the reflection loss as a function of grazing angle for this bottom model. Note that below 30◦ this bottom model predicts...less than 1 dB loss per ray bounce. 11 Figure 9: Jackson bottom reflection loss for sand at 15 kHz Absorption Loss The absorption loss in the medium was

Method and system for training dynamic nonlinear adaptive filters which have embedded memory

NASA Technical Reports Server (NTRS)

Rabinowitz, Matthew (Inventor)

2002-01-01

Described herein is a method and system for training nonlinear adaptive filters (or neural networks) which have embedded memory. Such memory can arise in a multi-layer finite impulse response (FIR) architecture, or an infinite impulse response (IIR) architecture. We focus on filter architectures with separate linear dynamic components and static nonlinear components. Such filters can be structured so as to restrict their degrees of computational freedom based on a priori knowledge about the dynamic operation to be emulated. The method is detailed for an FIR architecture which consists of linear FIR filters together with nonlinear generalized single layer subnets. For the IIR case, we extend the methodology to a general nonlinear architecture which uses feedback. For these dynamic architectures, we describe how one can apply optimization techniques which make updates closer to the Newton direction than those of a steepest descent method, such as backpropagation. We detail a novel adaptive modified Gauss-Newton optimization technique, which uses an adaptive learning rate to determine both the magnitude and direction of update steps. For a wide range of adaptive filtering applications, the new training algorithm converges faster and to a smaller value of cost than both steepest-descent methods such as backpropagation-through-time, and standard quasi-Newton methods. We apply the algorithm to modeling the inverse of a nonlinear dynamic tracking system 5, as well as a nonlinear amplifier 6.

A low-noise delta-sigma phase modulator for polar transmitters.

PubMed

Zhou, Bo

2014-01-01

A low-noise phase modulator, using finite-impulse-response (FIR) filtering embedded delta-sigma (ΔΣ) fractional-N phase-locked loop (PLL), is fabricated in 0.18 μ m CMOS for GSM/EDGE polar transmitters. A simplified digital compensation filter with inverse-FIR and -PLL features is proposed to trade off the transmitter noise and linearity. Experimental results show that the presented architecture performs RF phase modulation well with 20 mW power dissipation from 1.6 V supply and achieves the root-mean-square (rms) and peak phase errors of 4° and 8.5°, respectively. The measured and simulated phase noises of -104 dBc/Hz and -120 dBc/Hz at 400-kHz offset from 1.8-GHz carrier frequency are observed, respectively.

Novel programmable microwave photonic filter with arbitrary filtering shape and linear phase.

PubMed

Zhu, Xiaoqi; Chen, Feiya; Peng, Huanfa; Chen, Zhangyuan

2017-04-17

We propose and demonstrate a novel optical frequency comb (OFC) based microwave photonic filter which is able to realize arbitrary filtering shape with linear phase response. The shape of filter response is software programmable using finite impulse response (FIR) filter design method. By shaping the OFC spectrum using a programmable waveshaper, we can realize designed amplitude of FIR taps. Positive and negative sign of FIR taps are achieved by balanced photo-detection. The double sideband (DSB) modulation and symmetric distribution of filter taps are used to maintain the linear phase condition. In the experiment, we realize a fully programmable filter in the range from DC to 13.88 GHz. Four basic types of filters (lowpass, highpass, bandpass and bandstop) with different bandwidths, cut-off frequencies and central frequencies are generated. Also a triple-passband filter is realized in our experiment. To the best of our knowledge, it is the first demonstration of a programmable multiple passband MPF with linear phase response. The experiment shows good agreement with the theoretical result.

Detecting Structural Failures Via Acoustic Impulse Responses

NASA Technical Reports Server (NTRS)

Bayard, David S.; Joshi, Sanjay S.

1995-01-01

Advanced method of acoustic pulse reflectivity testing developed for use in determining sizes and locations of failures within structures. Used to detect breaks in electrical transmission lines, detect faults in optical fibers, and determine mechanical properties of materials. In method, structure vibrationally excited with acoustic pulse (a "ping") at one location and acoustic response measured at same or different location. Measured acoustic response digitized, then processed by finite-impulse-response (FIR) filtering algorithm unique to method and based on acoustic-wave-propagation and -reflection properties of structure. Offers several advantages: does not require training, does not require prior knowledge of mathematical model of acoustic response of structure, enables detection and localization of multiple failures, and yields data on extent of damage at each location.

A Low-Noise Delta-Sigma Phase Modulator for Polar Transmitters

PubMed Central

Zhou, Bo

2014-01-01

A low-noise phase modulator, using finite-impulse-response (FIR) filtering embedded delta-sigma (ΔΣ) fractional-N phase-locked loop (PLL), is fabricated in 0.18 μm CMOS for GSM/EDGE polar transmitters. A simplified digital compensation filter with inverse-FIR and -PLL features is proposed to trade off the transmitter noise and linearity. Experimental results show that the presented architecture performs RF phase modulation well with 20 mW power dissipation from 1.6 V supply and achieves the root-mean-square (rms) and peak phase errors of 4° and 8.5°, respectively. The measured and simulated phase noises of −104 dBc/Hz and −120 dBc/Hz at 400-kHz offset from 1.8-GHz carrier frequency are observed, respectively. PMID:24719578

In vivo evaluation of the effect of stimulus distribution on FIR statistical efficiency in event-related fMRI

PubMed Central

Jansma, J Martijn; de Zwart, Jacco A; van Gelderen, Peter; Duyn, Jeff H; Drevets, Wayne C; Furey, Maura L

2013-01-01

Technical developments in MRI have improved signal to noise, allowing use of analysis methods such as Finite impulse response (FIR) of rapid event related functional MRI (er-fMRI). FIR is one of the most informative analysis methods as it determines onset and full shape of the hemodynamic response function (HRF) without any a-priori assumptions. FIR is however vulnerable to multicollinearity, which is directly related to the distribution of stimuli over time. Efficiency can be optimized by simplifying a design, and restricting stimuli distribution to specific sequences, while more design flexibility necessarily reduces efficiency. However, the actual effect of efficiency on fMRI results has never been tested in vivo. Thus, it is currently difficult to make an informed choice between protocol flexibility and statistical efficiency. The main goal of this study was to assign concrete fMRI signal to noise values to the abstract scale of FIR statistical efficiency. Ten subjects repeated a perception task with five random and m-sequence based protocol, with varying but, according to literature, acceptable levels of multicollinearity. Results indicated substantial differences in signal standard deviation, while the level was a function of multicollinearity. Experiment protocols varied up to 55.4% in standard deviation. Results confirm that quality of fMRI in an FIR analysis can significantly and substantially vary with statistical efficiency. Our in vivo measurements can be used to aid in making an informed decision between freedom in protocol design and statistical efficiency. PMID:23473798

An Innovations-Based Noise Cancelling Technique on Inverse Kepstrum Whitening Filter and Adaptive FIR Filter in Beamforming Structure

PubMed Central

Jeong, Jinsoo

2011-01-01

This paper presents an acoustic noise cancelling technique using an inverse kepstrum system as an innovations-based whitening application for an adaptive finite impulse response (FIR) filter in beamforming structure. The inverse kepstrum method uses an innovations-whitened form from one acoustic path transfer function between a reference microphone sensor and a noise source so that the rear-end reference signal will then be a whitened sequence to a cascaded adaptive FIR filter in the beamforming structure. By using an inverse kepstrum filter as a whitening filter with the use of a delay filter, the cascaded adaptive FIR filter estimates only the numerator of the polynomial part from the ratio of overall combined transfer functions. The test results have shown that the adaptive FIR filter is more effective in beamforming structure than an adaptive noise cancelling (ANC) structure in terms of signal distortion in the desired signal and noise reduction in noise with nonminimum phase components. In addition, the inverse kepstrum method shows almost the same convergence level in estimate of noise statistics with the use of a smaller amount of adaptive FIR filter weights than the kepstrum method, hence it could provide better computational simplicity in processing. Furthermore, the rear-end inverse kepstrum method in beamforming structure has shown less signal distortion in the desired signal than the front-end kepstrum method and the front-end inverse kepstrum method in beamforming structure. PMID:22163987

Fast digital zooming system using directionally adaptive image interpolation and restoration.

PubMed

Kang, Wonseok; Jeon, Jaehwan; Yu, Soohwan; Paik, Joonki

2014-01-01

This paper presents a fast digital zooming system for mobile consumer cameras using directionally adaptive image interpolation and restoration methods. The proposed interpolation algorithm performs edge refinement along the initially estimated edge orientation using directionally steerable filters. Either the directionally weighted linear or adaptive cubic-spline interpolation filter is then selectively used according to the refined edge orientation for removing jagged artifacts in the slanted edge region. A novel image restoration algorithm is also presented for removing blurring artifacts caused by the linear or cubic-spline interpolation using the directionally adaptive truncated constrained least squares (TCLS) filter. Both proposed steerable filter-based interpolation and the TCLS-based restoration filters have a finite impulse response (FIR) structure for real time processing in an image signal processing (ISP) chain. Experimental results show that the proposed digital zooming system provides high-quality magnified images with FIR filter-based fast computational structure.

Hardware-efficient implementation of digital FIR filter using fast first-order moment algorithm

NASA Astrophysics Data System (ADS)

Cao, Li; Liu, Jianguo; Xiong, Jun; Zhang, Jing

2018-03-01

As the digital finite impulse response (FIR) filter can be transformed into the shift-add form of multiple small-sized firstorder moments, based on the existing fast first-order moment algorithm, this paper presents a novel multiplier-less structure to calculate any number of sequential filtering results in parallel. The theoretical analysis on its hardware and time-complexities reveals that by appropriately setting the degree of parallelism and the decomposition factor of a fixed word width, the proposed structure may achieve better area-time efficiency than the existing two-dimensional (2-D) memoryless-based filter. To evaluate the performance concretely, the proposed designs for different taps along with the existing 2-D memoryless-based filters, are synthesized by Synopsys Design Compiler with 0.18-μm SMIC library. The comparisons show that the proposed design has less area-time complexity and power consumption when the number of filter taps is larger than 48.

An advanced real-time digital signal processing system for linear systems emulation, with special emphasis on network and acoustic response characterization

NASA Astrophysics Data System (ADS)

Gaydecki, Patrick; Fernandes, Bosco

2003-11-01

A fast digital signal processing (DSP) system is described that can perform real-time emulation of a wide variety of linear audio-bandwidth systems and networks, such as reverberant spaces, musical instrument bodies and very high order filter networks. The hardware design is based upon a Motorola DSP56309 operating at 110 million multiplication-accumulations per second and a dual-channel 24 bit codec with a maximum sampling frequency of 192 kHz. High level software has been developed to express complex vector frequency responses as both infinite impulse response (IIR) and finite impulse response (FIR) coefficients, in a form suitable for real-time convolution by the firmware installed in the DSP system memory. An algorithm has also been devised to express IIR filters as equivalent FIR structures, thereby obviating the potential instabilities associated with recursive equations and negating the traditional deficiencies of FIR filters respecting equivalent analogue designs. The speed and dynamic range of the system is such that, when sampling at 48 kHz, the frequency response can be specified to a spectral precision of 22 Hz when sampling at 10 kHz, this resolution increases to 0.9 Hz. Moreover, it is also possible to control the phase of any frequency band with a theoretical precision of 10-5 degrees in all cases. The system has been applied in the study of analogue filter networks, real-time Hilbert transformation, phase-shift systems and musical instrument body emulation, where it is providing valuable new insights into the understanding of psychoacoustic mechanisms.

In vivo evaluation of the effect of stimulus distribution on FIR statistical efficiency in event-related fMRI.

PubMed

Jansma, J Martijn; de Zwart, Jacco A; van Gelderen, Peter; Duyn, Jeff H; Drevets, Wayne C; Furey, Maura L

2013-05-15

Technical developments in MRI have improved signal to noise, allowing use of analysis methods such as Finite impulse response (FIR) of rapid event related functional MRI (er-fMRI). FIR is one of the most informative analysis methods as it determines onset and full shape of the hemodynamic response function (HRF) without any a priori assumptions. FIR is however vulnerable to multicollinearity, which is directly related to the distribution of stimuli over time. Efficiency can be optimized by simplifying a design, and restricting stimuli distribution to specific sequences, while more design flexibility necessarily reduces efficiency. However, the actual effect of efficiency on fMRI results has never been tested in vivo. Thus, it is currently difficult to make an informed choice between protocol flexibility and statistical efficiency. The main goal of this study was to assign concrete fMRI signal to noise values to the abstract scale of FIR statistical efficiency. Ten subjects repeated a perception task with five random and m-sequence based protocol, with varying but, according to literature, acceptable levels of multicollinearity. Results indicated substantial differences in signal standard deviation, while the level was a function of multicollinearity. Experiment protocols varied up to 55.4% in standard deviation. Results confirm that quality of fMRI in an FIR analysis can significantly and substantially vary with statistical efficiency. Our in vivo measurements can be used to aid in making an informed decision between freedom in protocol design and statistical efficiency. Published by Elsevier B.V.

High-speed spectral calibration by complex FIR filter in phase-sensitive optical coherence tomography.

PubMed

Kim, Sangmin; Raphael, Patrick D; Oghalai, John S; Applegate, Brian E

2016-04-01

Swept-laser sources offer a number of advantages for Phase-sensitive Optical Coherence Tomography (PhOCT). However, inter- and intra-sweep variability leads to calibration errors that adversely affect phase sensitivity. While there are several approaches to overcoming this problem, our preferred method is to simply calibrate every sweep of the laser. This approach offers high accuracy and phase stability at the expense of a substantial processing burden. In this approach, the Hilbert phase of the interferogram from a reference interferometer provides the instantaneous wavenumber of the laser, but is computationally expensive. Fortunately, the Hilbert transform may be approximated by a Finite Impulse-Response (FIR) filter. Here we explore the use of several FIR filter based Hilbert transforms for calibration, explicitly considering the impact of filter choice on phase sensitivity and OCT image quality. Our results indicate that the complex FIR filter approach is the most robust and accurate among those considered. It provides similar image quality and slightly better phase sensitivity than the traditional FFT-IFFT based Hilbert transform while consuming fewer resources in an FPGA implementation. We also explored utilizing the Hilbert magnitude of the reference interferogram to calculate an ideal window function for spectral amplitude calibration. The ideal window function is designed to carefully control sidelobes on the axial point spread function. We found that after a simple chromatic correction, calculating the window function using the complex FIR filter and the reference interferometer gave similar results to window functions calculated using a mirror sample and the FFT-IFFT Hilbert transform. Hence, the complex FIR filter can enable accurate and high-speed calibration of the magnitude and phase of spectral interferograms.

High-speed spectral calibration by complex FIR filter in phase-sensitive optical coherence tomography

PubMed Central

Kim, Sangmin; Raphael, Patrick D.; Oghalai, John S.; Applegate, Brian E.

2016-01-01

Swept-laser sources offer a number of advantages for Phase-sensitive Optical Coherence Tomography (PhOCT). However, inter- and intra-sweep variability leads to calibration errors that adversely affect phase sensitivity. While there are several approaches to overcoming this problem, our preferred method is to simply calibrate every sweep of the laser. This approach offers high accuracy and phase stability at the expense of a substantial processing burden. In this approach, the Hilbert phase of the interferogram from a reference interferometer provides the instantaneous wavenumber of the laser, but is computationally expensive. Fortunately, the Hilbert transform may be approximated by a Finite Impulse-Response (FIR) filter. Here we explore the use of several FIR filter based Hilbert transforms for calibration, explicitly considering the impact of filter choice on phase sensitivity and OCT image quality. Our results indicate that the complex FIR filter approach is the most robust and accurate among those considered. It provides similar image quality and slightly better phase sensitivity than the traditional FFT-IFFT based Hilbert transform while consuming fewer resources in an FPGA implementation. We also explored utilizing the Hilbert magnitude of the reference interferogram to calculate an ideal window function for spectral amplitude calibration. The ideal window function is designed to carefully control sidelobes on the axial point spread function. We found that after a simple chromatic correction, calculating the window function using the complex FIR filter and the reference interferometer gave similar results to window functions calculated using a mirror sample and the FFT-IFFT Hilbert transform. Hence, the complex FIR filter can enable accurate and high-speed calibration of the magnitude and phase of spectral interferograms. PMID:27446666

A novel low-complexity digital filter design for wearable ECG devices

PubMed Central

Mehrnia, Alireza

2017-01-01

Wearable and implantable Electrocardiograph (ECG) devices are becoming prevailing tools for continuous real-time personal health monitoring. The ECG signal can be contaminated by various types of noise and artifacts (e.g., powerline interference, baseline wandering) that must be removed or suppressed for accurate ECG signal processing. Limited device size, power consumption and cost are critical issues that need to be carefully considered when designing any portable health monitoring device, including a battery-powered ECG device. This work presents a novel low-complexity noise suppression reconfigurable finite impulse response (FIR) filter structure for wearable ECG and heart monitoring devices. The design relies on a recently introduced optimally-factored FIR filter method. The new filter structure and several of its useful features are presented in detail. We also studied the hardware complexity of the proposed structure and compared it with the state-of-the-art. The results showed that the new ECG filter has a lower hardware complexity relative to the state-of-the-art ECG filters. PMID:28384272

Adaptively combined FIR and functional link artificial neural network equalizer for nonlinear communication channel.

PubMed

Zhao, Haiquan; Zhang, Jiashu

2009-04-01

This paper proposes a novel computational efficient adaptive nonlinear equalizer based on combination of finite impulse response (FIR) filter and functional link artificial neural network (CFFLANN) to compensate linear and nonlinear distortions in nonlinear communication channel. This convex nonlinear combination results in improving the speed while retaining the lower steady-state error. In addition, since the CFFLANN needs not the hidden layers, which exist in conventional neural-network-based equalizers, it exhibits a simpler structure than the traditional neural networks (NNs) and can require less computational burden during the training mode. Moreover, appropriate adaptation algorithm for the proposed equalizer is derived by the modified least mean square (MLMS). Results obtained from the simulations clearly show that the proposed equalizer using the MLMS algorithm can availably eliminate various intensity linear and nonlinear distortions, and be provided with better anti-jamming performance. Furthermore, comparisons of the mean squared error (MSE), the bit error rate (BER), and the effect of eigenvalue ratio (EVR) of input correlation matrix are presented.

A novel low-complexity digital filter design for wearable ECG devices.

PubMed

Asgari, Shadnaz; Mehrnia, Alireza

2017-01-01

Wearable and implantable Electrocardiograph (ECG) devices are becoming prevailing tools for continuous real-time personal health monitoring. The ECG signal can be contaminated by various types of noise and artifacts (e.g., powerline interference, baseline wandering) that must be removed or suppressed for accurate ECG signal processing. Limited device size, power consumption and cost are critical issues that need to be carefully considered when designing any portable health monitoring device, including a battery-powered ECG device. This work presents a novel low-complexity noise suppression reconfigurable finite impulse response (FIR) filter structure for wearable ECG and heart monitoring devices. The design relies on a recently introduced optimally-factored FIR filter method. The new filter structure and several of its useful features are presented in detail. We also studied the hardware complexity of the proposed structure and compared it with the state-of-the-art. The results showed that the new ECG filter has a lower hardware complexity relative to the state-of-the-art ECG filters.

Fast downscaled inverses for images compressed with M-channel lapped transforms.

PubMed

de Queiroz, R L; Eschbach, R

1997-01-01

Compressed images may be decompressed and displayed or printed using different devices at different resolutions. Full decompression and rescaling in space domain is a very expensive method. We studied downscaled inverses where the image is decompressed partially, and a reduced inverse transform is used to recover the image. In this fashion, fewer transform coefficients are used and the synthesis process is simplified. We studied the design of fast inverses, for a given forward transform. General solutions are presented for M-channel finite impulse response (FIR) filterbanks, of which block and lapped transforms are a subset. Designs of faster inverses are presented for popular block and lapped transforms.

The discrete prolate spheroidal filter as a digital signal processing tool

NASA Technical Reports Server (NTRS)

Mathews, J. D.; Breakall, J. K.; Karawas, G. K.

1983-01-01

The discrete prolate spheriodall (DPS) filter is one of the glass of nonrecursive finite impulse response (FIR) filters. The DPS filter is superior to other filters in this class in that it has maximum energy concentration in the frequency passband and minimum ringing in the time domain. A mathematical development of the DPS filter properties is given, along with information required to construct the filter. The properties of this filter were compared with those of the more commonly used filters of the same class. Use of the DPS filter allows for particularly meaningful statements of data time/frequency resolution cell values. The filter forms an especially useful tool for digital signal processing.

Optimal design of a bank of spatio-temporal filters for EEG signal classification.

PubMed

Higashi, Hiroshi; Tanaka, Toshihisa

2011-01-01

The spatial weights for electrodes called common spatial pattern (CSP) are known to be effective in EEG signal classification for motor imagery based brain computer interfaces (MI-BCI). To achieve accurate classification in CSP, the frequency filter should be properly designed. To this end, several methods for designing the filter have been proposed. However, the existing methods cannot consider plural brain activities described with different frequency bands and different spatial patterns such as activities of mu and beta rhythms. In order to efficiently extract these brain activities, we propose a method to design plural filters and spatial weights which extract desired brain activity. The proposed method designs finite impulse response (FIR) filters and the associated spatial weights by optimization of an objective function which is a natural extension of CSP. Moreover, we show by a classification experiment that the bank of FIR filters which are designed by introducing an orthogonality into the objective function can extract good discriminative features. Moreover, the experiment result suggests that the proposed method can automatically detect and extract brain activities related to motor imagery.

Low-cost space-varying FIR filter architecture for computational imaging systems

NASA Astrophysics Data System (ADS)

Feng, Guotong; Shoaib, Mohammed; Schwartz, Edward L.; Dirk Robinson, M.

2010-01-01

Recent research demonstrates the advantage of designing electro-optical imaging systems by jointly optimizing the optical and digital subsystems. The optical systems designed using this joint approach intentionally introduce large and often space-varying optical aberrations that produce blurry optical images. Digital sharpening restores reduced contrast due to these intentional optical aberrations. Computational imaging systems designed in this fashion have several advantages including extended depth-of-field, lower system costs, and improved low-light performance. Currently, most consumer imaging systems lack the necessary computational resources to compensate for these optical systems with large aberrations in the digital processor. Hence, the exploitation of the advantages of the jointly designed computational imaging system requires low-complexity algorithms enabling space-varying sharpening. In this paper, we describe a low-cost algorithmic framework and associated hardware enabling the space-varying finite impulse response (FIR) sharpening required to restore largely aberrated optical images. Our framework leverages the space-varying properties of optical images formed using rotationally-symmetric optical lens elements. First, we describe an approach to leverage the rotational symmetry of the point spread function (PSF) about the optical axis allowing computational savings. Second, we employ a specially designed bank of sharpening filters tuned to the specific radial variation common to optical aberrations. We evaluate the computational efficiency and image quality achieved by using this low-cost space-varying FIR filter architecture.

Optimal design of FIR triplet halfband filter bank and application in image coding.

PubMed

Kha, H H; Tuan, H D; Nguyen, T Q

2011-02-01

This correspondence proposes an efficient semidefinite programming (SDP) method for the design of a class of linear phase finite impulse response triplet halfband filter banks whose filters have optimal frequency selectivity for a prescribed regularity order. The design problem is formulated as the minimization of the least square error subject to peak error constraints and regularity constraints. By using the linear matrix inequality characterization of the trigonometric semi-infinite constraints, it can then be exactly cast as a SDP problem with a small number of variables and, hence, can be solved efficiently. Several design examples of the triplet halfband filter bank are provided for illustration and comparison with previous works. Finally, the image coding performance of the filter bank is presented.

Adaptive frequency-domain equalization in digital coherent optical receivers.

PubMed

Faruk, Md Saifuddin; Kikuchi, Kazuro

2011-06-20

We propose a novel frequency-domain adaptive equalizer in digital coherent optical receivers, which can reduce computational complexity of the conventional time-domain adaptive equalizer based on finite-impulse-response (FIR) filters. The proposed equalizer can operate on the input sequence sampled by free-running analog-to-digital converters (ADCs) at the rate of two samples per symbol; therefore, the arbitrary initial sampling phase of ADCs can be adjusted so that the best symbol-spaced sequence is produced. The equalizer can also be configured in the butterfly structure, which enables demultiplexing of polarization tributaries apart from equalization of linear transmission impairments. The performance of the proposed equalization scheme is verified by 40-Gbits/s dual-polarization quadrature phase-shift keying (QPSK) transmission experiments.

Joint polarization tracking and channel equalization based on radius-directed linear Kalman filter

NASA Astrophysics Data System (ADS)

Zhang, Qun; Yang, Yanfu; Zhong, Kangping; Liu, Jie; Wu, Xiong; Yao, Yong

2018-01-01

We propose a joint polarization tracking and channel equalization scheme based on radius-directed linear Kalman filter (RD-LKF) by introducing the butterfly finite-impulse-response (FIR) filter in our previously proposed RD-LKF method. Along with the fast polarization tracking, it can also simultaneously compensate the inter-symbol interference (ISI) effects including residual chromatic dispersion and polarization mode dispersion. Compared with the conventional radius-directed equalizer (RDE) algorithm, it is demonstrated experimentally that three times faster convergence speed, one order of magnitude better tracking capability, and better BER performance is obtained in polarization division multiplexing 16 quadrature amplitude modulation system. Besides, the influences of the algorithm parameters on the convergence and the tracking performance are investigated by numerical simulation.

Symmetric convolution of asymmetric multidimensional sequences using discrete trigonometric transforms.

PubMed

Foltz, T M; Welsh, B M

1999-01-01

This paper uses the fact that the discrete Fourier transform diagonalizes a circulant matrix to provide an alternate derivation of the symmetric convolution-multiplication property for discrete trigonometric transforms. Derived in this manner, the symmetric convolution-multiplication property extends easily to multiple dimensions using the notion of block circulant matrices and generalizes to multidimensional asymmetric sequences. The symmetric convolution of multidimensional asymmetric sequences can then be accomplished by taking the product of the trigonometric transforms of the sequences and then applying an inverse trigonometric transform to the result. An example is given of how this theory can be used for applying a two-dimensional (2-D) finite impulse response (FIR) filter with nonlinear phase which models atmospheric turbulence.

MULTISCALE ADAPTIVE SMOOTHING MODELS FOR THE HEMODYNAMIC RESPONSE FUNCTION IN FMRI*

PubMed Central

Wang, Jiaping; Zhu, Hongtu; Fan, Jianqing; Giovanello, Kelly; Lin, Weili

2012-01-01

In the event-related functional magnetic resonance imaging (fMRI) data analysis, there is an extensive interest in accurately and robustly estimating the hemodynamic response function (HRF) and its associated statistics (e.g., the magnitude and duration of the activation). Most methods to date are developed in the time domain and they have utilized almost exclusively the temporal information of fMRI data without accounting for the spatial information. The aim of this paper is to develop a multiscale adaptive smoothing model (MASM) in the frequency domain by integrating the spatial and temporal information to adaptively and accurately estimate HRFs pertaining to each stimulus sequence across all voxels in a three-dimensional (3D) volume. We use two sets of simulation studies and a real data set to examine the finite sample performance of MASM in estimating HRFs. Our real and simulated data analyses confirm that MASM outperforms several other state-of-art methods, such as the smooth finite impulse response (sFIR) model. PMID:24533041

Adaptive linear predictor FIR filter based on the Cyclone V FPGA with HPS to reduce narrow band RFI in AERA radio detection of cosmic rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szadkowski, Zbigniew

We present the new approach to a filtering of radio frequency interferences (RFI) in the Auger Engineering Radio Array (AERA) which study the electromagnetic part of the Extensive Air Showers. The radio stations can observe radio signals caused by coherent emissions due to geomagnetic radiation and charge excess processes. AERA observes frequency band from 30 to 80 MHz. This range is highly contaminated by human-made RFI. In order to improve the signal to noise ratio RFI filters are used in AERA to suppress this contamination. The first kind of filter used by AERA was the Median one, based on themore » Fast Fourier Transform (FFT) technique. The second one, which is currently in use, is the infinite impulse response (IIR) notch filter. The proposed new filter is a finite impulse response (FIR) filter based on a linear prediction (LP). A periodic contamination hidden in a registered signal (digitized in the ADC) can be extracted and next subtracted to make signal cleaner. The FIR filter requires a calculation of n=32, 64 or even 128 coefficients (dependent on a required speed or accuracy) by solving of n linear equations with coefficients built from the covariance Toeplitz matrix. This matrix can be solved by the Levinson recursion, which is much faster than the Gauss procedure. The filter has been already tested in the real AERA radio stations on Argentinean pampas with a very successful results. The linear equations were solved either in the virtual soft-core NIOSR processor (implemented in the FPGA chip as a net of logic elements) or in the external Voipac PXA270M ARM processor. The NIOS processor is relatively slow (50 MHz internal clock), calculations performed in an external processor consume a significant amount of time for data exchange between the FPGA and the processor. Test showed a very good efficiency of the RFI suppression for stationary (long-term) contaminations. However, we observed a short-time contaminations, which could not be suppressed either by the IIR-notch filter or by the FIR filter based on the linear predictions. For the LP FIR filter the refreshment time of the filter coefficients was to long and filter did not keep up with the changes of a contamination structure, mainly due to a long calculation time in a slow processors. We propose to use the Cyclone V SE chip with embedded micro-controller operating with 925 MHz internal clock to significantly reduce a refreshment time of the FIR coefficients. The lab results are promising. (authors)« less

Adaptive Identification and Control of Flow-Induced Cavity Oscillations

NASA Technical Reports Server (NTRS)

Kegerise, M. A.; Cattafesta, L. N.; Ha, C.

2002-01-01

Progress towards an adaptive self-tuning regulator (STR) for the cavity tone problem is discussed in this paper. Adaptive system identification algorithms were applied to an experimental cavity-flow tested as a prerequisite to control. In addition, a simple digital controller and a piezoelectric bimorph actuator were used to demonstrate multiple tone suppression. The control tests at Mach numbers of 0.275, 0.40, and 0.60 indicated approx. = 7dB tone reductions at multiple frequencies. Several different adaptive system identification algorithms were applied at a single freestream Mach number of 0.275. Adaptive finite-impulse response (FIR) filters of orders up to N = 100 were found to be unsuitable for modeling the cavity flow dynamics. Adaptive infinite-impulse response (IIR) filters of comparable order better captured the system dynamics. Two recursive algorithms, the least-mean square (LMS) and the recursive-least square (RLS), were utilized to update the adaptive filter coefficients. Given the sample-time requirements imposed by the cavity flow dynamics, the computational simplicity of the least mean squares (LMS) algorithm is advantageous for real-time control.

Clutter Mitigation in Echocardiography Using Sparse Signal Separation

PubMed Central

Yavneh, Irad

2015-01-01

In ultrasound imaging, clutter artifacts degrade images and may cause inaccurate diagnosis. In this paper, we apply a method called Morphological Component Analysis (MCA) for sparse signal separation with the objective of reducing such clutter artifacts. The MCA approach assumes that the two signals in the additive mix have each a sparse representation under some dictionary of atoms (a matrix), and separation is achieved by finding these sparse representations. In our work, an adaptive approach is used for learning the dictionary from the echo data. MCA is compared to Singular Value Filtering (SVF), a Principal Component Analysis- (PCA-) based filtering technique, and to a high-pass Finite Impulse Response (FIR) filter. Each filter is applied to a simulated hypoechoic lesion sequence, as well as experimental cardiac ultrasound data. MCA is demonstrated in both cases to outperform the FIR filter and obtain results comparable to the SVF method in terms of contrast-to-noise ratio (CNR). Furthermore, MCA shows a lower impact on tissue sections while removing the clutter artifacts. In experimental heart data, MCA obtains in our experiments clutter mitigation with an average CNR improvement of 1.33 dB. PMID:26199622

Design of efficient circularly symmetric two-dimensional variable digital FIR filters.

PubMed

Bindima, Thayyil; Elias, Elizabeth

2016-05-01

Circularly symmetric two-dimensional (2D) finite impulse response (FIR) filters find extensive use in image and medical applications, especially for isotropic filtering. Moreover, the design and implementation of 2D digital filters with variable fractional delay and variable magnitude responses without redesigning the filter has become a crucial topic of interest due to its significance in low-cost applications. Recently the design using fixed word length coefficients has gained importance due to the replacement of multipliers by shifters and adders, which reduces the hardware complexity. Among the various approaches to 2D design, transforming a one-dimensional (1D) filter to 2D by transformation, is reported to be an efficient technique. In this paper, 1D variable digital filters (VDFs) with tunable cut-off frequencies are designed using Farrow structure based interpolation approach, and the sub-filter coefficients in the Farrow structure are made multiplier-less using canonic signed digit (CSD) representation. The resulting performance degradation in the filters is overcome by using artificial bee colony (ABC) optimization. Finally, the optimized 1D VDFs are mapped to 2D using generalized McClellan transformation resulting in low complexity, circularly symmetric 2D VDFs with real-time tunability.

Design of efficient circularly symmetric two-dimensional variable digital FIR filters

PubMed Central

Bindima, Thayyil; Elias, Elizabeth

2016-01-01

Circularly symmetric two-dimensional (2D) finite impulse response (FIR) filters find extensive use in image and medical applications, especially for isotropic filtering. Moreover, the design and implementation of 2D digital filters with variable fractional delay and variable magnitude responses without redesigning the filter has become a crucial topic of interest due to its significance in low-cost applications. Recently the design using fixed word length coefficients has gained importance due to the replacement of multipliers by shifters and adders, which reduces the hardware complexity. Among the various approaches to 2D design, transforming a one-dimensional (1D) filter to 2D by transformation, is reported to be an efficient technique. In this paper, 1D variable digital filters (VDFs) with tunable cut-off frequencies are designed using Farrow structure based interpolation approach, and the sub-filter coefficients in the Farrow structure are made multiplier-less using canonic signed digit (CSD) representation. The resulting performance degradation in the filters is overcome by using artificial bee colony (ABC) optimization. Finally, the optimized 1D VDFs are mapped to 2D using generalized McClellan transformation resulting in low complexity, circularly symmetric 2D VDFs with real-time tunability. PMID:27222739

Adaptive feedforward control of non-minimum phase structural systems

NASA Astrophysics Data System (ADS)

Vipperman, J. S.; Burdisso, R. A.

1995-06-01

Adaptive feedforward control algorithms have been effectively applied to stationary disturbance rejection. For structural systems, the ideal feedforward compensator is a recursive filter which is a function of the transfer functions between the disturbance and control inputs and the error sensor output. Unfortunately, most control configurations result in a non-minimum phase control path; even a collocated control actuator and error sensor will not necessarily produce a minimum phase control path in the discrete domain. Therefore, the common practice is to choose a suitable approximation of the ideal compensator. In particular, all-zero finite impulse response (FIR) filters are desirable because of their inherent stability for adaptive control approaches. However, for highly resonant systems, large order filters are required for broadband applications. In this work, a control configuration is investigated for controlling non-minimum phase lightly damped structural systems. The control approach uses low order FIR filters as feedforward compensators in a configuration that has one more control actuator than error sensors. The performance of the controller was experimentally evaluated on a simply supported plate under white noise excitation for a two-input, one-output (2I1O) system. The results show excellent error signal reduction, attesting to the effectiveness of the method.

Landsat thematic mapper attitude data processing

NASA Technical Reports Server (NTRS)

Sehn, G. J.; Miller, S. F.

1984-01-01

The Landsat 4 and 5 satellites carry a new, high resolution, seven band thematic mapper imaging instrument. The spacecraft also carry two types of attitude sensors: a gyroscopic internal reference unit (IRU) which senses angular rate from dc to about 2 Hz, and an AC-coupled angular displacement sensor (ADS) measuring angular deviation above 2 Hz. A description of the derivation of the crossover network used to combine and equalize the IRU and ADS data is made. Also described are the digital data processing algorithms which produce the time history of the satellites' attitude motion including the finite impulse response (FIR) implementation of G and F filters; the resampling (interpolation/decimation) and synchronization of the IRU and ADS data; and the axis rotations required as a result of the on-board sensor locations on three orthogonal axes.

Hardware Design and Implementation of Fixed-Width Standard and Truncated 4×4, 6×6, 8×8 and 12×12-BIT Multipliers Using Fpga

NASA Astrophysics Data System (ADS)

Rais, Muhammad H.

2010-06-01

This paper presents Field Programmable Gate Array (FPGA) implementation of standard and truncated multipliers using Very High Speed Integrated Circuit Hardware Description Language (VHDL). Truncated multiplier is a good candidate for digital signal processing (DSP) applications such as finite impulse response (FIR) and discrete cosine transform (DCT). Remarkable reduction in FPGA resources, delay, and power can be achieved using truncated multipliers instead of standard parallel multipliers when the full precision of the standard multiplier is not required. The truncated multipliers show significant improvement as compared to standard multipliers. Results show that the anomaly in Spartan-3 AN average connection and maximum pin delay have been efficiently reduced in Virtex-4 device.

Space-time adaptive decision feedback neural receivers with data selection for high-data-rate users in DS-CDMA systems.

PubMed

de Lamare, Rodrigo C; Sampaio-Neto, Raimundo

2008-11-01

A space-time adaptive decision feedback (DF) receiver using recurrent neural networks (RNNs) is proposed for joint equalization and interference suppression in direct-sequence code-division multiple-access (DS-CDMA) systems equipped with antenna arrays. The proposed receiver structure employs dynamically driven RNNs in the feedforward section for equalization and multiaccess interference (MAI) suppression and a finite impulse response (FIR) linear filter in the feedback section for performing interference cancellation. A data selective gradient algorithm, based upon the set-membership (SM) design framework, is proposed for the estimation of the coefficients of RNN structures and is applied to the estimation of the parameters of the proposed neural receiver structure. Simulation results show that the proposed techniques achieve significant performance gains over existing schemes.

Evaluation of the FIR Example using Xilinx Vivado High-Level Synthesis Compiler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Zheming; Finkel, Hal; Yoshii, Kazutomo

Compared to central processing units (CPUs) and graphics processing units (GPUs), field programmable gate arrays (FPGAs) have major advantages in reconfigurability and performance achieved per watt. This development flow has been augmented with high-level synthesis (HLS) flow that can convert programs written in a high-level programming language to Hardware Description Language (HDL). Using high-level programming languages such as C, C++, and OpenCL for FPGA-based development could allow software developers, who have little FPGA knowledge, to take advantage of the FPGA-based application acceleration. This improves developer productivity and makes the FPGA-based acceleration accessible to hardware and software developers. Xilinx Vivado HLSmore » compiler is a high-level synthesis tool that enables C, C++ and System C specification to be directly targeted into Xilinx FPGAs without the need to create RTL manually. The white paper [1] published recently by Xilinx uses a finite impulse response (FIR) example to demonstrate the variable-precision features in the Vivado HLS compiler and the resource and power benefits of converting floating point to fixed point for a design. To get a better understanding of variable-precision features in terms of resource usage and performance, this report presents the experimental results of evaluating the FIR example using Vivado HLS 2017.1 and a Kintex Ultrascale FPGA. In addition, we evaluated the half-precision floating-point data type against the double-precision and single-precision data type and present the detailed results.« less

Integrated built-in-test false and missed alarms reduction based on forward infinite impulse response & recurrent finite impulse response dynamic neural networks

NASA Astrophysics Data System (ADS)

Cui, Yiqian; Shi, Junyou; Wang, Zili

2017-11-01

Built-in tests (BITs) are widely used in mechanical systems to perform state identification, whereas the BIT false and missed alarms cause trouble to the operators or beneficiaries to make correct judgments. Artificial neural networks (ANN) are previously used for false and missed alarms identification, which has the features such as self-organizing and self-study. However, these ANN models generally do not incorporate the temporal effect of the bottom-level threshold comparison outputs and the historical temporal features are not fully considered. To improve the situation, this paper proposes a new integrated BIT design methodology by incorporating a novel type of dynamic neural networks (DNN) model. The new DNN model is termed as Forward IIR & Recurrent FIR DNN (FIRF-DNN), where its component neurons, network structures, and input/output relationships are discussed. The condition monitoring false and missed alarms reduction implementation scheme based on FIRF-DNN model is also illustrated, which is composed of three stages including model training, false and missed alarms detection, and false and missed alarms suppression. Finally, the proposed methodology is demonstrated in the application study and the experimental results are analyzed.

Reconstructing the calibrated strain signal in the Advanced LIGO detectors

NASA Astrophysics Data System (ADS)

Viets, A. D.; Wade, M.; Urban, A. L.; Kandhasamy, S.; Betzwieser, J.; Brown, Duncan A.; Burguet-Castell, J.; Cahillane, C.; Goetz, E.; Izumi, K.; Karki, S.; Kissel, J. S.; Mendell, G.; Savage, R. L.; Siemens, X.; Tuyenbayev, D.; Weinstein, A. J.

2018-05-01

Advanced LIGO’s raw detector output needs to be calibrated to compute dimensionless strain h(t) . Calibrated strain data is produced in the time domain using both a low-latency, online procedure and a high-latency, offline procedure. The low-latency h(t) data stream is produced in two stages, the first of which is performed on the same computers that operate the detector’s feedback control system. This stage, referred to as the front-end calibration, uses infinite impulse response (IIR) filtering and performs all operations at a 16 384 Hz digital sampling rate. Due to several limitations, this procedure currently introduces certain systematic errors in the calibrated strain data, motivating the second stage of the low-latency procedure, known as the low-latency gstlal calibration pipeline. The gstlal calibration pipeline uses finite impulse response (FIR) filtering to apply corrections to the output of the front-end calibration. It applies time-dependent correction factors to the sensing and actuation components of the calibrated strain to reduce systematic errors. The gstlal calibration pipeline is also used in high latency to recalibrate the data, which is necessary due mainly to online dropouts in the calibrated data and identified improvements to the calibration models or filters.

Efficient multidimensional regularization for Volterra series estimation

NASA Astrophysics Data System (ADS)

Birpoutsoukis, Georgios; Csurcsia, Péter Zoltán; Schoukens, Johan

2018-05-01

This paper presents an efficient nonparametric time domain nonlinear system identification method. It is shown how truncated Volterra series models can be efficiently estimated without the need of long, transient-free measurements. The method is a novel extension of the regularization methods that have been developed for impulse response estimates of linear time invariant systems. To avoid the excessive memory needs in case of long measurements or large number of estimated parameters, a practical gradient-based estimation method is also provided, leading to the same numerical results as the proposed Volterra estimation method. Moreover, the transient effects in the simulated output are removed by a special regularization method based on the novel ideas of transient removal for Linear Time-Varying (LTV) systems. Combining the proposed methodologies, the nonparametric Volterra models of the cascaded water tanks benchmark are presented in this paper. The results for different scenarios varying from a simple Finite Impulse Response (FIR) model to a 3rd degree Volterra series with and without transient removal are compared and studied. It is clear that the obtained models capture the system dynamics when tested on a validation dataset, and their performance is comparable with the white-box (physical) models.

Orthonormal filters for identification in active control systems

NASA Astrophysics Data System (ADS)

Mayer, Dirk

2015-12-01

Many active noise and vibration control systems require models of the control paths. When the controlled system changes slightly over time, adaptive digital filters for the identification of the models are useful. This paper aims at the investigation of a special class of adaptive digital filters: orthonormal filter banks possess the robust and simple adaptation of the widely applied finite impulse response (FIR) filters, but at a lower model order, which is important when considering implementation on embedded systems. However, the filter banks require prior knowledge about the resonance frequencies and damping of the structure. This knowledge can be supposed to be of limited precision, since in many practical systems, uncertainties in the structural parameters exist. In this work, a procedure using a number of training systems to find the fixed parameters for the filter banks is applied. The effect of uncertainties in the prior knowledge on the model error is examined both with a basic example and in an experiment. Furthermore, the possibilities to compensate for the imprecise prior knowledge by a higher filter order are investigated. Also comparisons with FIR filters are implemented in order to assess the possible advantages of the orthonormal filter banks. Numerical and experimental investigations show that significantly lower computational effort can be reached by the filter banks under certain conditions.

Fluids and Combustion Facility: Fluids Integrated Rack Modal Model Correlation

NASA Technical Reports Server (NTRS)

McNelis, Mark E.; Suarez, Vicente J.; Sullivan, Timothy L.; Otten, Kim D.; Akers, James C.

2005-01-01

The Fluids Integrated Rack (FIR) is one of two racks in the Fluids and Combustion Facility on the International Space Station. The FIR is dedicated to the scientific investigation of space system fluids management supporting NASA s Exploration of Space Initiative. The FIR hardware was modal tested and FIR finite element model updated to satisfy the International Space Station model correlation criteria. The final cross-orthogonality results between the correlated model and test mode shapes was greater than 90 percent for all primary target modes.

WE-D-204-02: Novel Method for Correcting Degradation of Sharpness of Liquid-Crystal Display Based On Modulation Transfer Function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tokurei, S; Department of Radiology, Yamaguchi University Hospital, Ube, Yamaguchi; Morishita, J

2015-06-15

Purpose: To develop a method for improving sharpness of images reproduced on liquid-crystal displays (LCDs) by compensating for the degradation of modulation transfer function (MTF) of the LCD. Methods: The inherent MTF of a color LCD (display MTF) was measured using a commercially available color digital camera. The frequency responses necessary to compensate for the resolution property of the LCD were calculated from the inverses of the display MTFs in both the horizontal and vertical directions. In addition, the inverses of the display MTFs were combined with the response of the human eye. The finite impulse response (FIR) filters weremore » computed by taking the inverse Fourier transform of the frequency responses, and the effects of the FIR filtering on both the resolution and noise properties of the displayed images were verified by measuring the MTF and Wiener spectrum (WS), respectively. The FIR filtering was then applied to the representation of digital bone and chest radiographs. Results: The FIR filtering improved the MTF values by up to almost 1.0 or greater over the frequency range of interest, while it minimally increased the WS values. Combining the inverses of the display MTFs with the response of the human eye led to further refinement of the MTF. Our method was successfully and beneficially applied to the image interpretation of bone radiographs. The resolution enhancement of chest radiographs, which include larger scattered radiation than bone radiographs, was easily perceived by incorporating the response of the human eye. In addition, no artifacts were observed on the processed images. Conclusion: Our proposed method to compensate for the degradation of the resolution properties of LCDs has the potential to improve the observer performance of radiologists when reading digital radiographs. This work was supported in part by grant from EIZO Corporation.« less

The Least Mean Squares Adaptive FIR Filter for Narrow-Band RFI Suppression in Radio Detection of Cosmic Rays

NASA Astrophysics Data System (ADS)

Szadkowski, Zbigniew; Głas, Dariusz

2017-06-01

Radio emission from the extensive air showers (EASs), initiated by ultrahigh-energy cosmic rays, was theoretically suggested over 50 years ago. However, due to technical limitations, successful collection of sufficient statistics can take several years. Nowadays, this detection technique is used in many experiments consisting in studying EAS. One of them is the Auger Engineering Radio Array (AERA), located within the Pierre Auger Observatory. AERA focuses on the radio emission, generated by the electromagnetic part of the shower, mainly in geomagnetic and charge excess processes. The frequency band observed by AERA radio stations is 30-80 MHz. Thus, the frequency range is contaminated by human-made and narrow-band radio frequency interferences (RFIs). Suppression of contaminations is very important to lower the rate of spurious triggers. There are two kinds of digital filters used in AERA radio stations to suppress these contaminations: the fast Fourier transform median filter and four narrow-band IIR-notch filters. Both filters have worked successfully in the field for many years. An adaptive filter based on a least mean squares (LMS) algorithm is a relatively simple finite impulse response (FIR) filter, which can be an alternative for currently used filters. Simulations in MATLAB are very promising and show that the LMS filter can be very efficient in suppressing RFI and only slightly distorts radio signals. The LMS algorithm was implemented into a Cyclone V field programmable gate array for testing the stability, RFI suppression efficiency, and adaptation time to new conditions. First results show that the FIR filter based on the LMS algorithm can be successfully implemented and used in real AERA radio stations.

Finite-time resilient decentralized control for interconnected impulsive switched systems with neutral delay.

PubMed

Ren, Hangli; Zong, Guangdeng; Hou, Linlin; Yang, Yi

2017-03-01

This paper is concerned with the problem of finite-time control for a class of interconnected impulsive switched systems with neutral delay in which the time-varying delay appears in both the state and the state derivative. The concepts of finite-time boundedness and finite-time stability are respectively extended to interconnected impulsive switched systems with neutral delay for the first time. By applying the average dwell time method, sufficient conditions are first derived to cope with the problem of finite-time boundedness and finite-time stability for interconnected impulsive switched systems with neutral delay. In addition, the purpose of finite-time resilient decentralized control is to construct a resilient decentralized state-feedback controller such that the closed-loop system is finite-time bounded and finite-time stable. All the conditions are formulated in terms of linear matrix inequalities to ensure finite-time boundedness and finite-time stability of the given system. Finally, an example is presented to illustrate the effectiveness of the proposed approach. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Recursive Inversion By Finite-Impulse-Response Filters

NASA Technical Reports Server (NTRS)

Bach, Ralph E., Jr.; Baram, Yoram

1991-01-01

Recursive approximation gives least-squares best fit to exact response. Algorithm yields finite-impulse-response approximation of unknown single-input/single-output, causal, time-invariant, linear, real system, response of which is sequence of impulses. Applicable to such system-inversion problems as suppression of echoes and identification of target from its scatter response to incident impulse.

Time Delay Estimation

DTIC Science & Technology

1976-04-09

of the signal and noise remain HH ***^-^*--~ 53 h, to r(Mc) h2(r» r(we) Figure 3-2 Sy&toetric Impulse Response for Two FIR Linear Phase...Inputs x,y and Outputs x.j. , 15 2-2 Linear System with Impulse Response h("r) 23 2-3 Model of Error Resulting from Linearly Filtering x(t) to...Corrupted with Additive Noise 42 2-6 Model of Directional Signal Corrupted with Additive Noise and Processed .... 45 2-7 Source Driving Two

Cloud Model-Based Artificial Immune Network for Complex Optimization Problem

PubMed Central

Wang, Mingan; Li, Jianming; Guo, Dongliang

2017-01-01

This paper proposes an artificial immune network based on cloud model (AINet-CM) for complex function optimization problems. Three key immune operators—cloning, mutation, and suppression—are redesigned with the help of the cloud model. To be specific, an increasing half cloud-based cloning operator is used to adjust the dynamic clone multipliers of antibodies, an asymmetrical cloud-based mutation operator is used to control the adaptive evolution of antibodies, and a normal similarity cloud-based suppressor is used to keep the diversity of the antibody population. To quicken the searching convergence, a dynamic searching step length strategy is adopted. For comparative study, a series of numerical simulations are arranged between AINet-CM and the other three artificial immune systems, that is, opt-aiNet, IA-AIS, and AAIS-2S. Furthermore, two industrial applications—finite impulse response (FIR) filter design and proportional-integral-differential (PID) controller tuning—are investigated and the results demonstrate the potential searching capability and practical value of the proposed AINet-CM algorithm. PMID:28630620

Signal propagation in cortical networks: a digital signal processing approach.

PubMed

Rodrigues, Francisco Aparecido; da Fontoura Costa, Luciano

2009-01-01

This work reports a digital signal processing approach to representing and modeling transmission and combination of signals in cortical networks. The signal dynamics is modeled in terms of diffusion, which allows the information processing undergone between any pair of nodes to be fully characterized in terms of a finite impulse response (FIR) filter. Diffusion without and with time decay are investigated. All filters underlying the cat and macaque cortical organization are found to be of low-pass nature, allowing the cortical signal processing to be summarized in terms of the respective cutoff frequencies (a high cutoff frequency meaning little alteration of signals through their intermixing). Several findings are reported and discussed, including the fact that the incorporation of temporal activity decay tends to provide more diversified cutoff frequencies. Different filtering intensity is observed for each community in those networks. In addition, the brain regions involved in object recognition tend to present the highest cutoff frequencies for both the cat and macaque networks.

Design of adaptive control systems by means of self-adjusting transversal filters

NASA Technical Reports Server (NTRS)

Merhav, S. J.

1986-01-01

The design of closed-loop adaptive control systems based on nonparametric identification was addressed. Implementation is by self-adjusting Least Mean Square (LMS) transversal filters. The design concept is Model Reference Adaptive Control (MRAC). Major issues are to preserve the linearity of the error equations of each LMS filter, and to prevent estimation bias that is due to process or measurement noise, thus providing necessary conditions for the convergence and stability of the control system. The controlled element is assumed to be asymptotically stable and minimum phase. Because of the nonparametric Finite Impulse Response (FIR) estimates provided by the LMS filters, a-priori information on the plant model is needed only in broad terms. Following a survey of control system configurations and filter design considerations, system implementation is shown here in Single Input Single Output (SISO) format which is readily extendable to multivariable forms. In extensive computer simulation studies the controlled element is represented by a second-order system with widely varying damping, natural frequency, and relative degree.

Artifact removal from EEG signals using adaptive filters in cascade

NASA Astrophysics Data System (ADS)

Garcés Correa, A.; Laciar, E.; Patiño, H. D.; Valentinuzzi, M. E.

2007-11-01

Artifacts in EEG (electroencephalogram) records are caused by various factors, like line interference, EOG (electro-oculogram) and ECG (electrocardiogram). These noise sources increase the difficulty in analyzing the EEG and to obtaining clinical information. For this reason, it is necessary to design specific filters to decrease such artifacts in EEG records. In this paper, a cascade of three adaptive filters based on a least mean squares (LMS) algorithm is proposed. The first one eliminates line interference, the second adaptive filter removes the ECG artifacts and the last one cancels EOG spikes. Each stage uses a finite impulse response (FIR) filter, which adjusts its coefficients to produce an output similar to the artifacts present in the EEG. The proposed cascade adaptive filter was tested in five real EEG records acquired in polysomnographic studies. In all cases, line-frequency, ECG and EOG artifacts were attenuated. It is concluded that the proposed filter reduces the common artifacts present in EEG signals without removing significant information embedded in these records.

Perfect blind restoration of images blurred by multiple filters: theory and efficient algorithms.

PubMed

Harikumar, G; Bresler, Y

1999-01-01

We address the problem of restoring an image from its noisy convolutions with two or more unknown finite impulse response (FIR) filters. We develop theoretical results about the existence and uniqueness of solutions, and show that under some generically true assumptions, both the filters and the image can be determined exactly in the absence of noise, and stably estimated in its presence. We present efficient algorithms to estimate the blur functions and their sizes. These algorithms are of two types, subspace-based and likelihood-based, and are extensions of techniques proposed for the solution of the multichannel blind deconvolution problem in one dimension. We present memory and computation-efficient techniques to handle the very large matrices arising in the two-dimensional (2-D) case. Once the blur functions are determined, they are used in a multichannel deconvolution step to reconstruct the unknown image. The theoretical and practical implications of edge effects, and "weakly exciting" images are examined. Finally, the algorithms are demonstrated on synthetic and real data.

Cloud Model-Based Artificial Immune Network for Complex Optimization Problem.

PubMed

Wang, Mingan; Feng, Shuo; Li, Jianming; Li, Zhonghua; Xue, Yu; Guo, Dongliang

2017-01-01

This paper proposes an artificial immune network based on cloud model (AINet-CM) for complex function optimization problems. Three key immune operators-cloning, mutation, and suppression-are redesigned with the help of the cloud model. To be specific, an increasing half cloud-based cloning operator is used to adjust the dynamic clone multipliers of antibodies, an asymmetrical cloud-based mutation operator is used to control the adaptive evolution of antibodies, and a normal similarity cloud-based suppressor is used to keep the diversity of the antibody population. To quicken the searching convergence, a dynamic searching step length strategy is adopted. For comparative study, a series of numerical simulations are arranged between AINet-CM and the other three artificial immune systems, that is, opt-aiNet, IA-AIS, and AAIS-2S. Furthermore, two industrial applications-finite impulse response (FIR) filter design and proportional-integral-differential (PID) controller tuning-are investigated and the results demonstrate the potential searching capability and practical value of the proposed AINet-CM algorithm.

Spatio-Temporal Equalizer for a Receiving-Antenna Feed Array

NASA Technical Reports Server (NTRS)

Mukai, Ryan; Lee, Dennis; Vilnrotter, Victor

2010-01-01

A spatio-temporal equalizer has been conceived as an improved means of suppressing multipath effects in the reception of aeronautical telemetry signals, and may be adaptable to radar and aeronautical communication applications as well. This equalizer would be an integral part of a system that would also include a seven-element planar array of receiving feed horns centered at the focal point of a paraboloidal antenna that would be nominally aimed at or near the aircraft that would be the source of the signal that one seeks to receive (see Figure 1). This spatio-temporal equalizer would consist mostly of a bank of seven adaptive finite-impulse-response (FIR) filters one for each element in the array - and the outputs of the filters would be summed (see Figure 2). The combination of the spatial diversity of the feedhorn array and the temporal diversity of the filter bank would afford better multipath-suppression performance than is achievable by means of temporal equalization alone. The seven-element feed array would supplant the single feed horn used in a conventional paraboloidal ground telemetry-receiving antenna. The radio-frequency telemetry signals re ceiv ed by the seven elements of the array would be digitized, converted to complex baseband form, and sent to the FIR filter bank, which would adapt itself in real time to enable reception of telemetry at a low bit error rate, even in the presence of multipath of the type found at many flight test ranges.

Two-dimensional heat flow analysis applied to heat sterilization of ponderosa pine and Douglas-fir square timbers

Treesearch

William T. Simpson

2004-01-01

Equations for a two-dimensional finite difference heat flow analysis were developed and applied to ponderosa pine and Douglas-fir square timbers to calculate the time required to heat the center of the squares to target temperature. The squares were solid piled, which made their surfaces inaccessible to the heating air, and thus surface temperatures failed to attain...

Wideband aperture array using RF channelizers and massively parallel digital 2D IIR filterbank

NASA Astrophysics Data System (ADS)

Sengupta, Arindam; Madanayake, Arjuna; Gómez-García, Roberto; Engeberg, Erik D.

2014-05-01

Wideband receive-mode beamforming applications in wireless location, electronically-scanned antennas for radar, RF sensing, microwave imaging and wireless communications require digital aperture arrays that offer a relatively constant far-field beam over several octaves of bandwidth. Several beamforming schemes including the well-known true time-delay and the phased array beamformers have been realized using either finite impulse response (FIR) or fast Fourier transform (FFT) digital filter-sum based techniques. These beamforming algorithms offer the desired selectivity at the cost of a high computational complexity and frequency-dependant far-field array patterns. A novel approach to receiver beamforming is the use of massively parallel 2-D infinite impulse response (IIR) fan filterbanks for the synthesis of relatively frequency independent RF beams at an order of magnitude lower multiplier complexity compared to FFT or FIR filter based conventional algorithms. The 2-D IIR filterbanks demand fast digital processing that can support several octaves of RF bandwidth, fast analog-to-digital converters (ADCs) for RF-to-bits type direct conversion of wideband antenna element signals. Fast digital implementation platforms that can realize high-precision recursive filter structures necessary for real-time beamforming, at RF radio bandwidths, are also desired. We propose a novel technique that combines a passive RF channelizer, multichannel ADC technology, and single-phase massively parallel 2-D IIR digital fan filterbanks, realized at low complexity using FPGA and/or ASIC technology. There exists native support for a larger bandwidth than the maximum clock frequency of the digital implementation technology. We also strive to achieve More-than-Moore throughput by processing a wideband RF signal having content with N-fold (B = N Fclk/2) bandwidth compared to the maximum clock frequency Fclk Hz of the digital VLSI platform under consideration. Such increase in bandwidth is achieved without use of polyphase signal processing or time-interleaved ADC methods. That is, all digital processors operate at the same Fclk clock frequency without phasing, while wideband operation is achieved by sub-sampling of narrower sub-bands at the the RF channelizer outputs.

Boundary implications for frequency response of interval FIR and IIR filters

NASA Technical Reports Server (NTRS)

Bose, N. K.; Kim, K. D.

1991-01-01

It is shown that vertex implication results in parameter space apply to interval trigonometric polynomials. Subsequently, it is shown that the frequency responses of both interval FIR and IIR filters are bounded by the frequency responses of certain extreme filters. The results apply directly in the evaluation of properties of designed filters, especially because it is more realistic to bound the filter coefficients from above and below instead of determining those with infinite precision because of finite arithmetic effects. Illustrative examples are provided to show how the extreme filters might be easily derived in any specific interval FIR or IIR filter design problem.

Development of Software for a Lidar-Altimeter Processor

NASA Technical Reports Server (NTRS)

Rosenberg, Jacob S.; Trujillo, Carlos

2005-01-01

A report describes the development of software for a digital processor that operates in conjunction with a finite-impulse-response (FIR) chip in a spaceborne lidar altimeter. Processing is started by a laser-fire interrupt signal that is repeated at intervals of 25 ms. For the purpose of discriminating between returns from the ground and returns from such things as trees, buildings, and clouds, the software is required to scan digitized lidar-return data in reverse of the acquisition sequence in order to distinguish the last return pulse from within a commanded ground-return range window. The digitized waveform information within this range window is filtered through 6 matched filters, in the hardware electronics, in order to maximize the probability of finding echoes from sloped or rough terrain and minimize the probability of selecting cloud returns. From the data falling past the end of the range window, there is obtained a noise baseline that is used to calculate a threshold value for each filter. The data from each filter is analyzed by a complex weighting scheme and the filter with the greatest weight is selected. A region around the peak of the ground return pulse associated with the selected filter is placed in telemetry, as well as information on its location, height, and other characteristics. The software requires many uplinked parameters as input. Included in the report is a discussion of major software-development problems posed by the design of the FIR chip and the need for the software to complete its process within 20 ms to fit within the overall 25-ms cycle.

On the performance of piezoelectric harvesters loaded by finite width impulses

NASA Astrophysics Data System (ADS)

Doria, A.; Medè, C.; Desideri, D.; Maschio, A.; Codecasa, L.; Moro, F.

2018-02-01

The response of cantilevered piezoelectric harvesters loaded by finite width impulses of base acceleration is studied analytically in the frequency domain in order to identify the parameters that influence the generated voltage. Experimental tests are then performed on harvesters loaded by hammer impacts. The latter are used to confirm analytical results and to validate a linear finite element (FE) model of a unimorph harvester. The FE model is, in turn, used to extend analytical results to more general harvesters (tapered, inverse tapered, triangular) and to more general impulses (heel strike in human gait). From analytical and numerical results design criteria for improving harvester performance are obtained.

A periodic spatio-spectral filter for event-related potentials.

PubMed

Ghaderi, Foad; Kim, Su Kyoung; Kirchner, Elsa Andrea

2016-12-01

With respect to single trial detection of event-related potentials (ERPs), spatial and spectral filters are two of the most commonly used pre-processing techniques for signal enhancement. Spatial filters reduce the dimensionality of the data while suppressing the noise contribution and spectral filters attenuate frequency components that most likely belong to noise subspace. However, the frequency spectrum of ERPs overlap with that of the ongoing electroencephalogram (EEG) and different types of artifacts. Therefore, proper selection of the spectral filter cutoffs is not a trivial task. In this research work, we developed a supervised method to estimate the spatial and finite impulse response (FIR) spectral filters, simultaneously. We evaluated the performance of the method on offline single trial classification of ERPs in datasets recorded during an oddball paradigm. The proposed spatio-spectral filter improved the overall single-trial classification performance by almost 9% on average compared with the case that no spatial filters were used. We also analyzed the effects of different spectral filter lengths and the number of retained channels after spatial filtering. Copyright © 2016. Published by Elsevier Ltd.

Time-domain prefilter design for enhanced tracking and vibration suppression in machine motion control

NASA Astrophysics Data System (ADS)

Cole, Matthew O. T.; Shinonawanik, Praween; Wongratanaphisan, Theeraphong

2018-05-01

Structural flexibility can impact negatively on machine motion control systems by causing unmeasured positioning errors and vibration at locations where accurate motion is important for task execution. To compensate for these effects, command signal prefiltering may be applied. In this paper, a new FIR prefilter design method is described that combines finite-time vibration cancellation with dynamic compensation properties. The time-domain formulation exploits the relation between tracking error and the moment values of the prefilter impulse response function. Optimal design solutions for filters having minimum H2 norm are derived and evaluated. The control approach does not require additional actuation or sensing and can be effective even without complete and accurate models of the machine dynamics. Results from implementation and testing on an experimental high-speed manipulator having a Delta robot architecture with directionally compliant end-effector are presented. The results show the importance of prefilter moment values for tracking performance and confirm that the proposed method can achieve significant reductions in both peak and RMS tracking error, as well as settling time, for complex motion patterns.

Continuous Mass Measurement on Conveyor Belt

NASA Astrophysics Data System (ADS)

Tomobe, Yuki; Tasaki, Ryosuke; Yamazaki, Takanori; Ohnishi, Hideo; Kobayashi, Masaaki; Kurosu, Shigeru

The continuous mass measurement of packages on a conveyor belt will become greatly important. In the mass measurement, the sequence of products is generally random. An interesting possibility of raising throughput of the conveyor line without increasing the conveyor belt speed is offered by the use of two or three conveyor belt scales (called a multi-stage conveyor belt scale). The multi-stage conveyor belt scale can be created which will adjust the conveyor belt length to the product length. The conveyor belt scale usually has maximum capacities of less than 80kg and 140cm, and achieves measuring rates of more than 150 packages per minute and more. The output signals from the conveyor belt scale are always contaminated with noises due to vibrations of the conveyor and the product to be measured in motion. In this paper an employed digital filter is of Finite Impulse Response (FIR) type designed under the consideration on the dynamics of the conveyor system. The experimental results on the conveyor belt scale suggest that the filtering algorithms are effective enough to practical applications to some extent.

Compact FPGA-based beamformer using oversampled 1-bit A/D converters.

PubMed

Tomov, Borislav Gueorguiev; Jensen, Jørgen Arendt

2005-05-01

A compact medical ultrasound beamformer architecture that uses oversampled 1-bit analog-to-digital (A/D) converters is presented. Sparse sample processing is used, as the echo signal for the image lines is reconstructed in 512 equidistant focal points along the line through its in-phase and quadrature components. That information is sufficient for presenting a B-mode image and creating a color flow map. The high sampling rate provides the necessary delay resolution for the focusing. The low channel data width (1-bit) makes it possible to construct a compact beamformer logic. The signal reconstruction is done using finite impulse reponse (FIR) filters, applied on selected bit sequences of the delta-sigma modulator output stream. The approach allows for a multichannel beamformer to fit in a single field programmable gate array (FPGA) device. A 32-channel beamformer is estimated to occupy 50% of the available logic resources in a commercially available mid-range FPGA, and to be able to operate at 129 MHz. Simulation of the architecture at 140 MHz provides images with a dynamic range approaching 60 dB for an excitation frequency of 3 MHz.

Programmable noise bandwidth reduction by means of digital averaging

NASA Technical Reports Server (NTRS)

Poklemba, John J. (Inventor)

1993-01-01

Predetection noise bandwidth reduction is effected by a pre-averager capable of digitally averaging the samples of an input data signal over two or more symbols, the averaging interval being defined by the input sampling rate divided by the output sampling rate. As the averaged sample is clocked to a suitable detector at a much slower rate than the input signal sampling rate the noise bandwidth at the input to the detector is reduced, the input to the detector having an improved signal to noise ratio as a result of the averaging process, and the rate at which such subsequent processing must operate is correspondingly reduced. The pre-averager forms a data filter having an output sampling rate of one sample per symbol of received data. More specifically, selected ones of a plurality of samples accumulated over two or more symbol intervals are output in response to clock signals at a rate of one sample per symbol interval. The pre-averager includes circuitry for weighting digitized signal samples using stored finite impulse response (FIR) filter coefficients. A method according to the present invention is also disclosed.

Space Shuttle Main Engine High Pressure Fuel Turbopump Turbine Blade Cracking

NASA Technical Reports Server (NTRS)

Lee, Henry

1988-01-01

The analytical results from two-dimensional (2D) and three-dimensional (3D) finite element model investigations into the cracking of Space Shuttle Main Engine (SSME) High Pressure Fuel Turbopump (HPFTP) first- and second-stage turbine blades are presented. Specifically, the initiation causes for transverse cracks on the pressure side of the firststage blade fir tree lobes and face/corner cracks on the downstream fir tree face of the second-state blade are evaluated. Because the blade material, MAR-M-246 Hf (DS), is highly susceptible to hydrogen embrittlement in the -100 F to 400 F thermal environment, a steady-state condition (full power level = 109 percent) rather than a start-up or shut-down transient was considered to be the most likely candidate for generating a high-strain state in the fir tree areas. Results of the analyses yielded strain levels on both first- and second-stage blade fir tree regions that are of a magnitude to cause hydrogen assisted low cycle fatigue cracking. Also evident from the analysis is that a positive margin against fir tree cracking exists for the planned design modifications, which include shot peening for both first- and second-stage blade fir tree areas.

A floating-point digital receiver for MRI.

PubMed

Hoenninger, John C; Crooks, Lawrence E; Arakawa, Mitsuaki

2002-07-01

A magnetic resonance imaging (MRI) system requires the highest possible signal fidelity and stability for clinical applications. Quadrature analog receivers have problems with channel matching, dc offset and analog-to-digital linearity. Fixed-point digital receivers (DRs) reduce all of these problems. We have demonstrated that a floating-point DR using large (order 124 to 512) FIR low-pass filters also overcomes these problems, automatically provides long word length and has low latency between signals. A preloaded table of finite impuls response (FIR) filter coefficients provides fast switching between one of 129 different one-stage and two-stage multrate FIR low-pass filters with bandwidths between 4 KHz and 125 KHz. This design has been implemented on a dual channel circuit board for a commercial MRI system.

High-Q microwave photonic filter with a tuned modulator.

PubMed

Capmany, J; Mora, J; Ortega, B; Pastor, D

2005-09-01

We propose the use of tuned electro-optic or electroabsorption external modulators to implement high-quality (high-Q) factor, single-bandpass photonic filters for microwave signals. Using this approach, we experimentally demonstrate a transversal finite impulse response with a Q factor of 237. This is to our knowledge the highest value ever reported for a passive finite impulse-response microwave photonic filter.

A Model-Based Approach to Trial-By-Trial P300 Amplitude Fluctuations

PubMed Central

Kolossa, Antonio; Fingscheidt, Tim; Wessel, Karl; Kopp, Bruno

2013-01-01

It has long been recognized that the amplitude of the P300 component of event-related brain potentials is sensitive to the degree to which eliciting stimuli are surprising to the observers (Donchin, 1981). While Squires et al. (1976) showed and modeled dependencies of P300 amplitudes from observed stimuli on various time scales, Mars et al. (2008) proposed a computational model keeping track of stimulus probabilities on a long-term time scale. We suggest here a computational model which integrates prior information with short-term, long-term, and alternation-based experiential influences on P300 amplitude fluctuations. To evaluate the new model, we measured trial-by-trial P300 amplitude fluctuations in a simple two-choice response time task, and tested the computational models of trial-by-trial P300 amplitudes using Bayesian model evaluation. The results reveal that the new digital filtering (DIF) model provides a superior account of the trial-by-trial P300 amplitudes when compared to both Squires et al.’s (1976) model, and Mars et al.’s (2008) model. We show that the P300-generating system can be described as two parallel first-order infinite impulse response (IIR) low-pass filters and an additional fourth-order finite impulse response (FIR) high-pass filter. Implications of the acquired data are discussed with regard to the neurobiological distinction between short-term, long-term, and working memory as well as from the point of view of predictive coding models and Bayesian learning theories of cortical function. PMID:23404628

Loss tolerant speech decoder for telecommunications

NASA Technical Reports Server (NTRS)

Prieto, Jr., Jaime L. (Inventor)

1999-01-01

A method and device for extrapolating past signal-history data for insertion into missing data segments in order to conceal digital speech frame errors. The extrapolation method uses past-signal history that is stored in a buffer. The method is implemented with a device that utilizes a finite-impulse response (FIR) multi-layer feed-forward artificial neural network that is trained by back-propagation for one-step extrapolation of speech compression algorithm (SCA) parameters. Once a speech connection has been established, the speech compression algorithm device begins sending encoded speech frames. As the speech frames are received, they are decoded and converted back into speech signal voltages. During the normal decoding process, pre-processing of the required SCA parameters will occur and the results stored in the past-history buffer. If a speech frame is detected to be lost or in error, then extrapolation modules are executed and replacement SCA parameters are generated and sent as the parameters required by the SCA. In this way, the information transfer to the SCA is transparent, and the SCA processing continues as usual. The listener will not normally notice that a speech frame has been lost because of the smooth transition between the last-received, lost, and next-received speech frames.

45 Gb/s low complexity optical front-end for soft-decision LDPC decoders.

PubMed

Sakib, Meer Nazmus; Moayedi, Monireh; Gross, Warren J; Liboiron-Ladouceur, Odile

2012-07-30

In this paper a low complexity and energy efficient 45 Gb/s soft-decision optical front-end to be used with soft-decision low-density parity-check (LDPC) decoders is demonstrated. The results show that the optical front-end exhibits a net coding gain of 7.06 and 9.62 dB for post forward error correction bit error rate of 10(-7) and 10(-12) for long block length LDPC(32768,26803) code. The performance over a hard decision front-end is 1.9 dB for this code. It is shown that the soft-decision circuit can also be used as a 2-bit flash type analog-to-digital converter (ADC), in conjunction with equalization schemes. At bit rate of 15 Gb/s using RS(255,239), LDPC(672,336), (672, 504), (672, 588), and (1440, 1344) used with a 6-tap finite impulse response (FIR) equalizer will result in optical power savings of 3, 5, 7, 9.5 and 10.5 dB, respectively. The 2-bit flash ADC consumes only 2.71 W at 32 GSamples/s. At 45 GSamples/s the power consumption is estimated to be 4.95 W.

Finite-time robust passive control for a class of switched reaction-diffusion stochastic complex dynamical networks with coupling delays and impulsive control

NASA Astrophysics Data System (ADS)

Syed Ali, M.; Yogambigai, J.; Kwon, O. M.

2018-03-01

Finite-time boundedness and finite-time passivity for a class of switched stochastic complex dynamical networks (CDNs) with coupling delays, parameter uncertainties, reaction-diffusion term and impulsive control are studied. Novel finite-time synchronisation criteria are derived based on passivity theory. This paper proposes a CDN consisting of N linearly and diffusively coupled identical reaction- diffusion neural networks. By constructing of a suitable Lyapunov-Krasovskii's functional and utilisation of Jensen's inequality and Wirtinger's inequality, new finite-time passivity criteria for the networks are established in terms of linear matrix inequalities (LMIs), which can be checked numerically using the effective LMI toolbox in MATLAB. Finally, two interesting numerical examples are given to show the effectiveness of the theoretical results.

Finite-time synchronization of complex networks with non-identical nodes and impulsive disturbances

NASA Astrophysics Data System (ADS)

Zhang, Wanli; Li, Chuandong; He, Xing; Li, Hongfei

2018-01-01

This paper investigates the finite-time synchronization of complex networks (CNs) with non-identical nodes and impulsive disturbances. By utilizing stability theories, new 1-norm-based analytical techniques and suitable comparison, systems, several sufficient conditions are obtained to realize the synchronization goal in finite time. State feedback controllers with and without the sign function are designed. Results show that the controllers with sign function can reduce the conservativeness of control gains and the controllers without sign function can overcome the chattering phenomenon. Numerical simulations are offered to verify the effectiveness of the theoretical analysis.

Adaptive nonlinear polynomial neural networks for control of boundary layer/structural interaction

NASA Technical Reports Server (NTRS)

Parker, B. Eugene, Jr.; Cellucci, Richard L.; Abbott, Dean W.; Barron, Roger L.; Jordan, Paul R., III; Poor, H. Vincent

1993-01-01

The acoustic pressures developed in a boundary layer can interact with an aircraft panel to induce significant vibration in the panel. Such vibration is undesirable due to the aerodynamic drag and structure-borne cabin noises that result. The overall objective of this work is to develop effective and practical feedback control strategies for actively reducing this flow-induced structural vibration. This report describes the results of initial evaluations using polynomial, neural network-based, feedback control to reduce flow induced vibration in aircraft panels due to turbulent boundary layer/structural interaction. Computer simulations are used to develop and analyze feedback control strategies to reduce vibration in a beam as a first step. The key differences between this work and that going on elsewhere are as follows: that turbulent and transitional boundary layers represent broadband excitation and thus present a more complex stochastic control scenario than that of narrow band (e.g., laminar boundary layer) excitation; and secondly, that the proposed controller structures are adaptive nonlinear infinite impulse response (IIR) polynomial neural network, as opposed to the traditional adaptive linear finite impulse response (FIR) filters used in most studies to date. The controllers implemented in this study achieved vibration attenuation of 27 to 60 dB depending on the type of boundary layer established by laminar, turbulent, and intermittent laminar-to-turbulent transitional flows. Application of multi-input, multi-output, adaptive, nonlinear feedback control of vibration in aircraft panels based on polynomial neural networks appears to be feasible today. Plans are outlined for Phase 2 of this study, which will include extending the theoretical investigation conducted in Phase 2 and verifying the results in a series of laboratory experiments involving both bum and plate models.

Conditional parametric models for storm sewer runoff

NASA Astrophysics Data System (ADS)

Jonsdottir, H.; Nielsen, H. Aa; Madsen, H.; Eliasson, J.; Palsson, O. P.; Nielsen, M. K.

2007-05-01

The method of conditional parametric modeling is introduced for flow prediction in a sewage system. It is a well-known fact that in hydrological modeling the response (runoff) to input (precipitation) varies depending on soil moisture and several other factors. Consequently, nonlinear input-output models are needed. The model formulation described in this paper is similar to the traditional linear models like final impulse response (FIR) and autoregressive exogenous (ARX) except that the parameters vary as a function of some external variables. The parameter variation is modeled by local lines, using kernels for local linear regression. As such, the method might be referred to as a nearest neighbor method. The results achieved in this study were compared to results from the conventional linear methods, FIR and ARX. The increase in the coefficient of determination is substantial. Furthermore, the new approach conserves the mass balance better. Hence this new approach looks promising for various hydrological models and analysis.

FPGA/NIOS Implementation of an Adaptive FIR Filter Using Linear Prediction to Reduce Narrow-Band RFI for Radio Detection of Cosmic Rays

NASA Astrophysics Data System (ADS)

Szadkowski, Zbigniew; Fraenkel, E. D.; van den Berg, Ad M.

2013-10-01

We present the FPGA/NIOS implementation of an adaptive finite impulse response (FIR) filter based on linear prediction to suppress radio frequency interference (RFI). This technique will be used for experiments that observe coherent radio emission from extensive air showers induced by ultra-high-energy cosmic rays. These experiments are designed to make a detailed study of the development of the electromagnetic part of air showers. Therefore, these radio signals provide information that is complementary to that obtained by water-Cherenkov detectors which are predominantly sensitive to the particle content of an air shower at ground. The radio signals from air showers are caused by the coherent emission due to geomagnetic and charge-excess processes. These emissions can be observed in the frequency band between 10-100 MHz. However, this frequency range is significantly contaminated by narrow-band RFI and other human-made distortions. A FIR filter implemented in the FPGA logic segment of the front-end electronics of a radio sensor significantly improves the signal-to-noise ratio. In this paper we discuss an adaptive filter which is based on linear prediction. The coefficients for the linear predictor (LP) are dynamically refreshed and calculated in the embedded NIOS processor, which is implemented in the same FPGA chip. The Levinson recursion, used to obtain the filter coefficients, is also implemented in the NIOS and is partially supported by direct multiplication in the DSP blocks of the logic FPGA segment. Tests confirm that the LP can be an alternative to other methods involving multiple time-to-frequency domain conversions using an FFT procedure. These multiple conversions draw heavily on the power consumption of the FPGA and are avoided by the linear prediction approach. Minimization of the power consumption is an important issue because the final system will be powered by solar panels. The FIR filter has been successfully tested in the Altera development kits with the EP4CE115F29C7 from the Cyclone IV family and the EP3C120F780C7 from the Cyclone III family at a 170 MHz sampling rate, a 12-bit I/O resolution, and an internal 30-bit dynamic range. Most of the slow floating-point NIOS calculations have been moved to the FPGA logic segments as extended fixed-point operations, which significantly reduced the refreshing time of the coefficients used in the LP. We conclude that the LP is a viable alternative to other methods such as non-adaptive methods involving digital notch filters or multiple time-to-frequency domain conversions using an FFT procedure.

Spatiotemporal models for the simulation of infrared backgrounds

NASA Astrophysics Data System (ADS)

Wilkes, Don M.; Cadzow, James A.; Peters, R. Alan, II; Li, Xingkang

1992-09-01

It is highly desirable for designers of automatic target recognizers (ATRs) to be able to test their algorithms on targets superimposed on a wide variety of background imagery. Background imagery in the infrared spectrum is expensive to gather from real sources, consequently, there is a need for accurate models for producing synthetic IR background imagery. We have developed a model for such imagery that will do the following: Given a real, infrared background image, generate another image, distinctly different from the one given, that has the same general visual characteristics as well as the first and second-order statistics of the original image. The proposed model consists of a finite impulse response (FIR) kernel convolved with an excitation function, and histogram modification applied to the final solution. A procedure for deriving the FIR kernel using a signal enhancement algorithm has been developed, and the histogram modification step is a simple memoryless nonlinear mapping that imposes the first order statistics of the original image onto the synthetic one, thus the overall model is a linear system cascaded with a memoryless nonlinearity. It has been found that the excitation function relates to the placement of features in the image, the FIR kernel controls the sharpness of the edges and the global spectrum of the image, and the histogram controls the basic coloration of the image. A drawback to this method of simulating IR backgrounds is that a database of actual background images must be collected in order to produce accurate FIR and histogram models. If this database must include images of all types of backgrounds obtained at all times of the day and all times of the year, the size of the database would be prohibitive. In this paper we propose improvements to the model described above that enable time-dependent modeling of the IR background. This approach can greatly reduce the number of actual IR backgrounds that are required to produce a sufficiently accurate mathematical model for synthesizing a similar IR background for different times of the day. Original and synthetic IR backgrounds will be presented. Previous research in simulating IR backgrounds was performed by Strenzwilk, et al., Botkin, et al., and Rapp. The most recent work of Strenzwilk, et al. was based on the use of one-dimensional ARMA models for synthesizing the images. Their results were able to retain the global statistical and spectral behavior of the original image, but the synthetic image was not visually very similar to the original. The research presented in this paper is the result of an attempt to improve upon their results, and represents a significant improvement in quality over previously obtained results.

Proposal of a calculation method to determine the structural components' contribution on the deceleration of a passenger compartment based on the energy-derivative method.

PubMed

Nagasaka, Kei; Mizuno, Koji; Ito, Daisuke; Saida, Naoya

2017-05-29

In car crashes, the passenger compartment deceleration significantly influences the occupant loading. Hence, it is important to consider how each structural component deforms in order to control the passenger compartment deceleration. In frontal impact tests, the passenger compartment deceleration depends on the energy absorption property of the front structures. However, at this point in time there are few papers describing the components' quantitative contributions on the passenger compartment deceleration. Generally, the cross-sectional force is used to examine each component's contribution to passenger compartment deceleration. However, it is difficult to determine each component's contribution based on the cross-sectional forces, especially within segments of the individual members itself such as the front rails, because the force is transmitted continuously and the cross-sectional forces remain the same through the component. The deceleration of a particle can be determined from the derivative of the kinetic energy. Using this energy-derivative method, the contribution of each component on the passenger compartment deceleration can be determined. Using finite element (FE) car models, this method was applied for full-width and offset impact tests. This method was also applied to evaluate the deceleration of the powertrain. The finite impulse response (FIR) coefficient of the vehicle deceleration (input) and the driver chest deceleration (output) was calculated from Japan New Car Assessment Program (JNCAP) tests. These were applied to the component's contribution on the vehicle deceleration in FE analysis, and the component's contribution to the deceleration of the driver's chest was determined. The sum of the contribution of each component coincides with the passenger compartment deceleration in all types of impacts; therefore, the validity of this method was confirmed. In the full-width impact, the contribution of the crush box was large in the initial phases, and the contribution of the passenger compartment was large in the final phases. For the powertrain deceleration, the crush box had a positive contribution and the passenger compartment had a negative contribution. In the offset test, the contribution of the honeycomb and the passenger compartment deformation to the passenger compartment deceleration was large. Based on the FIR analysis, the passenger compartment deformation contributed the most to the chest deceleration of the driver dummy in the full-width impact. Based on the energy-derivative method, the contribution of the components' deformation to deceleration of the passenger compartment can be calculated for various types of crash configurations more easily, directly, and quantitatively than by using conventional methods. In addition, by combining the energy-derivative method and FIR, each structure's contribution to the occupant deceleration can be obtained. The energy-derivative method is useful in investigating how the deceleration develops from component deformations and also in designing deceleration curves for various impact configurations.

An approach for fixed coefficient RNS-based FIR filter

NASA Astrophysics Data System (ADS)

Srinivasa Reddy, Kotha; Sahoo, Subhendu Kumar

2017-08-01

In this work, an efficient new modular multiplication method for {2k-1, 2k, 2k+1-1} moduli set is proposed to implement a residue number system (RNS)-based fixed coefficient finite impulse response filter. The new multiplication approach reduces the number of partial products by using pre-loaded product block. The reduction in partial products with the proposed modular multiplication improves the clock frequency and reduces the area and power as compared with the conventional modular multiplication. Further, the present approach eliminates a binary number to residue number converter circuit, which is usually needed at the front end of RNS-based system. In this work, two fixed coefficient filter architectures with the new modular multiplication approach are proposed. The filters are implemented using Verilog hardware description language. The United Microelectronics Corporation 90 nm technology library has been used for synthesis and the results area, power and delay are obtained with the help of Cadence register transfer level compiler. The power delay product (PDP) is also considered for performance comparison among the proposed filters. One of the proposed architecture is found to improve PDP gain by 60.83% as compared with the filter implemented with conventional modular multiplier. The filters functionality is validated with the help of Altera DSP Builder.

A Dynamic Attitude Measurement System Based on LINS

PubMed Central

Li, Hanzhou; Pan, Quan; Wang, Xiaoxu; Zhang, Juanni; Li, Jiang; Jiang, Xiangjun

2014-01-01

A dynamic attitude measurement system (DAMS) is developed based on a laser inertial navigation system (LINS). Three factors of the dynamic attitude measurement error using LINS are analyzed: dynamic error, time synchronization and phase lag. An optimal coning errors compensation algorithm is used to reduce coning errors, and two-axis wobbling verification experiments are presented in the paper. The tests indicate that the attitude accuracy is improved 2-fold by the algorithm. In order to decrease coning errors further, the attitude updating frequency is improved from 200 Hz to 2000 Hz. At the same time, a novel finite impulse response (FIR) filter with three notches is designed to filter the dither frequency of the ring laser gyro (RLG). The comparison tests suggest that the new filter is five times more effective than the old one. The paper indicates that phase-frequency characteristics of FIR filter and first-order holder of navigation computer constitute the main sources of phase lag in LINS. A formula to calculate the LINS attitude phase lag is introduced in the paper. The expressions of dynamic attitude errors induced by phase lag are derived. The paper proposes a novel synchronization mechanism that is able to simultaneously solve the problems of dynamic test synchronization and phase compensation. A single-axis turntable and a laser interferometer are applied to verify the synchronization mechanism. The experiments results show that the theoretically calculated values of phase lag and attitude error induced by phase lag can both match perfectly with testing data. The block diagram of DAMS and physical photos are presented in the paper. The final experiments demonstrate that the real-time attitude measurement accuracy of DAMS can reach up to 20″ (1σ) and the synchronization error is less than 0.2 ms on the condition of three axes wobbling for 10 min. PMID:25177802

Reception of Multiple Telemetry Signals via One Dish Antenna

NASA Technical Reports Server (NTRS)

Mukai, Ryan; Vilnrotter, Victor

2010-01-01

A microwave aeronautical-telemetry receiver system includes an antenna comprising a seven-element planar array of receiving feed horns centered at the focal point of a paraboloidal dish reflector that is nominally aimed at a single aircraft or at multiple aircraft flying in formation. Through digital processing of the signals received by the seven feed horns, the system implements a method of enhanced cancellation of interference, such that it becomes possible to receive telemetry signals in the same frequency channel simultaneously from either or both of two aircraft at slightly different angular positions within the field of view of the antenna, even in the presence of multipath propagation. The present system is an advanced version of the system described in Spatio- Temporal Equalizer for a Receiving-Antenna Feed Array NPO-43077, NASA Tech Briefs, Vol. 34, No. 2 (February 2010), page 32. To recapitulate: The radio-frequency telemetry signals received by the seven elements of the array are digitized, converted to complex baseband form, and sent to a spatio-temporal equalizer that consists mostly of a bank of seven adaptive finite-impulse-response (FIR) filters (one for each element in the array) plus a unit that sums the outputs of the filters. The combination of the spatial diversity of the feedhorn array and the temporal diversity of the filter bank affords better multipath suppression performance than is achievable by means of temporal equalization alone. The FIR filter bank adapts itself in real time to enable reception of telemetry at a low bit error rate, even in the presence of frequency-selective multipath propagation like that commonly found at flight-test ranges. The combination of the array and the filter bank makes it possible to constructively add multipath incoming signals to the corresponding directly arriving signals, thereby enabling reductions in telemetry bit-error rates.

Earth-ionosphere transmission line model for an impulsive geomagnetic disturbance at the dayside geomagnetic equator

NASA Astrophysics Data System (ADS)

Kikuchi, T.

2004-12-01

The near instantaneous onset of a geomagnetic impulse such as the preliminary reverse impulse (PRI) of the geomagnetic sudden commencement at high latitude and at the dayside geomagnetic equator has been explained by means of the TM0 mode waves in the Earth-ionosphere waveguide (Kikuchi and Araki, J. Atmosph. Terrest. Phys., 41, 927-936, 1979). There is, on the other hand, a time lag of the order of 10 sec in the peak amplitude of the magnetic impulse at the dayside equator. To explain these two temporal aspects, we examine transmission of the TM0 mode in a finite-length Earth-ionosphere transmission line composed of a finitely conducting ionosphere and the perfectly conducting Earth, with a fixed electric potential at one end and null potential at the other end of the transmission line, corresponding to the foot of a field-aligned current on the dawn- or dusk-side in the polar cap and middle point on the noon-midnight meridian at low latitude, respectively. Successive transmission and reflection in the bounded transmission line lead to that the ionospheric currents start to grow instantaneously, but reach a steady state with a relaxation time proportional to the length of the transmission line and the ionospheric conductivity. The relaxation time is of the order of 10 sec when we give high conductivity applicable to the equatorial ionosphere, which matches the observed time lag in the peak amplitude of the equatorial geomagnetic impulse. Consequently, the TM0 mode in the finite-length Earth-ionosphere transmission line explains both the instantaneous onset and time lag in the peak amplitude of the geomagnetic impulse at the dayside geomagnetic equator.

Cat Swarm Optimization algorithm for optimal linear phase FIR filter design.

PubMed

Saha, Suman Kumar; Ghoshal, Sakti Prasad; Kar, Rajib; Mandal, Durbadal

2013-11-01

In this paper a new meta-heuristic search method, called Cat Swarm Optimization (CSO) algorithm is applied to determine the best optimal impulse response coefficients of FIR low pass, high pass, band pass and band stop filters, trying to meet the respective ideal frequency response characteristics. CSO is generated by observing the behaviour of cats and composed of two sub-models. In CSO, one can decide how many cats are used in the iteration. Every cat has its' own position composed of M dimensions, velocities for each dimension, a fitness value which represents the accommodation of the cat to the fitness function, and a flag to identify whether the cat is in seeking mode or tracing mode. The final solution would be the best position of one of the cats. CSO keeps the best solution until it reaches the end of the iteration. The results of the proposed CSO based approach have been compared to those of other well-known optimization methods such as Real Coded Genetic Algorithm (RGA), standard Particle Swarm Optimization (PSO) and Differential Evolution (DE). The CSO based results confirm the superiority of the proposed CSO for solving FIR filter design problems. The performances of the CSO based designed FIR filters have proven to be superior as compared to those obtained by RGA, conventional PSO and DE. The simulation results also demonstrate that the CSO is the best optimizer among other relevant techniques, not only in the convergence speed but also in the optimal performances of the designed filters. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Vibrational Responses Of Structures To Impulses

NASA Technical Reports Server (NTRS)

Zak, Michail A.

1990-01-01

Report discusses propagation of vibrations in structure in response to impulsive and/or concentrated loads. Effects of pulsed loads treated by analyzing propagation of characteristic vibrational waves explicitly through each member of structure. This wave-front analysis used in combination with usual finite-element modal analysis to obtain more accurate representation of overall vibrational behavior.

Robust Frequency Invariant Beamforming with Low Sidelobe for Speech Enhancement

NASA Astrophysics Data System (ADS)

Zhu, Yiting; Pan, Xiang

2018-01-01

Frequency invariant beamformers (FIBs) are widely used in speech enhancement and source localization. There are two traditional optimization methods for FIB design. The first one is convex optimization, which is simple but the frequency invariant characteristic of the beam pattern is poor with respect to frequency band of five octaves. The least squares (LS) approach using spatial response variation (SRV) constraint is another optimization method. Although, it can provide good frequency invariant property, it usually couldn’t be used in speech enhancement for its lack of weight norm constraint which is related to the robustness of a beamformer. In this paper, a robust wideband beamforming method with a constant beamwidth is proposed. The frequency invariant beam pattern is achieved by resolving an optimization problem of the SRV constraint to cover speech frequency band. With the control of sidelobe level, it is available for the frequency invariant beamformer (FIB) to prevent distortion of interference from the undesirable direction. The approach is completed in time-domain by placing tapped delay lines(TDL) and finite impulse response (FIR) filter at the output of each sensor which is more convenient than the Frost processor. By invoking the weight norm constraint, the robustness of the beamformer is further improved against random errors. Experiment results show that the proposed method has a constant beamwidth and almost the same white noise gain as traditional delay-and-sum (DAS) beamformer.

Time-fixed rendezvous by impulse factoring with an intermediate timing constraint. [for transfer orbits

NASA Technical Reports Server (NTRS)

Green, R. N.; Kibler, J. F.; Young, G. R.

1974-01-01

A method is presented for factoring a two-impulse orbital transfer into a three- or four-impulse transfer which solves the rendezvous problem and satisfies an intermediate timing constraint. Both the time of rendezvous and the intermediate time of a alinement are formulated as any element of a finite sequence of times. These times are integer multiples of a constant plus an additive constant. The rendezvous condition is an equality constraint, whereas the intermediate alinement is an inequality constraint. The two timing constraints are satisfied by factoring the impulses into collinear parts that vectorially sum to the original impulse and by varying the resultant period differences and the number of revolutions in each orbit. Five different types of solutions arise by considering factoring either or both of the two impulses into two or three parts with a limit for four total impulses. The impulse-factoring technique may be applied to any two-impulse transfer which has distinct orbital periods.

A finite element study of the EIDI system. [Electro-Impulse De-Icing System

NASA Technical Reports Server (NTRS)

Khatkhate, A. A.; Scavuzzo, R. J.; Chu, M. L.

1988-01-01

This paper presents a method for modeling the structural dynamics of an Electro-Impulse De-Icing System, using finite element analyses procedures. A guideline for building a representative finite element model is discussed. Modeling was done initially using four noded cubic elements, four noded isoparametric plate elements and eight noded isoparametric shell elements. Due to the size of the problem and due to the underestimation of shear stress results when compared to previous analytical work an approximate model was created to predict possible areas of shedding of ice. There appears to be good agreement with the test data provided by The Boeing Commercial Airplane Company. Thus these initial results of this method were found to be encouraging. Additional analytical work and comparison with experiment is needed in order to completely evaluate this approach.

Recursive inversion of externally defined linear systems

NASA Technical Reports Server (NTRS)

Bach, Ralph E., Jr.; Baram, Yoram

1988-01-01

The approximate inversion of an internally unknown linear system, given by its impulse response sequence, by an inverse system having a finite impulse response, is considered. The recursive least squares procedure is shown to have an exact initialization, based on the triangular Toeplitz structure of the matrix involved. The proposed approach also suggests solutions to the problems of system identification and compensation.

A Finite-Element Method Model of Soft Tissue Response to Impulsive Acoustic Radiation Force

PubMed Central

Palmeri, Mark L.; Sharma, Amy C.; Bouchard, Richard R.; Nightingale, Roger W.; Nightingale, Kathryn R

2010-01-01

Several groups are studying acoustic radiation force and its ability to image the mechanical properties of tissue. Acoustic radiation force impulse (ARFI) imaging is one modality using standard diagnostic ultrasound scanners to generate localized, impulsive, acoustic radiation forces in tissue. The dynamic response of tissue is measured via conventional ultrasonic speckle-tracking methods and provides information about the mechanical properties of tissue. A finite-element method (FEM) model has been developed that simulates the dynamic response of tissues, with and without spherical inclusions, to an impulsive acoustic radiation force excitation from a linear array transducer. These FEM models were validated with calibrated phantoms. Shear wave speed, and therefore elasticity, dictates tissue relaxation following ARFI excitation, but Poisson’s ratio and density do not significantly alter tissue relaxation rates. Increased acoustic attenuation in tissue increases the relative amount of tissue displacement in the near field compared with the focal depth, but relaxation rates are not altered. Applications of this model include improving image quality, and distilling material and structural information from tissue’s dynamic response to ARFI excitation. Future work on these models includes incorporation of viscous material properties and modeling the ultrasonic tracking of displaced scatterers. PMID:16382621

Modeling and control of flexible space structures

NASA Technical Reports Server (NTRS)

Wie, B.; Bryson, A. E., Jr.

1981-01-01

The effects of actuator and sensor locations on transfer function zeros are investigated, using uniform bars and beams as generic models of flexible space structures. It is shown how finite element codes may be used directly to calculate transfer function zeros. The impulse response predicted by finite-dimensional models is compared with the exact impulse response predicted by the infinite dimensional models. It is shown that some flexible structures behave as if there were a direct transmission between actuator and sensor (equal numbers of zeros and poles in the transfer function). Finally, natural damping models for a vibrating beam are investigated since natural damping has a strong influence on the appropriate active control logic for a flexible structure.

Dynamic monitoring of compliant bodies impacting the water surface through local strain measurements

NASA Astrophysics Data System (ADS)

Panciroli, Riccardo; Biscarini, Chiara; Jannelli, Elio; Ubertini, Filippo; Ubertini, Stefano

2016-04-01

The understanding and the experimental characterization of the evolution of impulsive loading is crucial in several fields in structural, mechanical and ocean engineering, naval architecture and aerospace. In this regards, we developed an experimental methodology to reconstruct the deformed shape of compliant bodies subjected to impulsive loadings, as those encountered in water entry events, starting from a finite number of local strain measurements performed through Fiber Bragg Gratings. The paper discusses the potential applications of the proposed methodology for: i) real-time damage detection and structural health monitoring, ii) fatigue assessment and iii) impulsive load estimation.

An Efficient Implementation For Real Time Applications Of The Wigner-Ville Distribution

NASA Astrophysics Data System (ADS)

Boashash, Boualem; Black, Peter; Whitehouse, Harper J.

1986-03-01

The Wigner-Ville Distribution (WVD) is a valuable tool for time-frequency signal analysis. In order to implement the WVD in real time an efficient algorithm and architecture have been developed which may be implemented with commercial components. This algorithm successively computes the analytic signal corresponding to the input signal, forms a weighted kernel function and analyses the kernel via a Discrete Fourier Transform (DFT). To evaluate the analytic signal required by the algorithm it is shown that the time domain definition implemented as a finite impulse response (FIR) filter is practical and more efficient than the frequency domain definition of the analytic signal. The windowed resolution of the WVD in the frequency domain is shown to be similar to the resolution of a windowed Fourier Transform. A real time signal processsor has been designed for evaluation of the WVD analysis system. The system is easily paralleled and can be configured to meet a variety of frequency and time resolutions. The arithmetic unit is based on a pair of high speed VLSI floating-point multiplier and adder chips. Dual operand buses and an independent result bus maximize data transfer rates. The system is horizontally microprogrammed and utilizes a full instruction pipeline. Each microinstruction specifies two operand addresses, a result location, the type of arithmetic and the memory configuration. input and output is via shared memory blocks with front-end processors to handle data transfers during the non access periods of the analyzer.

Novel mathematical algorithm for pupillometric data analysis.

PubMed

Canver, Matthew C; Canver, Adam C; Revere, Karen E; Amado, Defne; Bennett, Jean; Chung, Daniel C

2014-01-01

Pupillometry is used clinically to evaluate retinal and optic nerve function by measuring pupillary response to light stimuli. We have developed a mathematical algorithm to automate and expedite the analysis of non-filtered, non-calculated pupillometric data obtained from mouse pupillary light reflex recordings, obtained from dynamic pupillary diameter recordings following exposure of varying light intensities. The non-filtered, non-calculated pupillometric data is filtered through a low pass finite impulse response (FIR) filter. Thresholding is used to remove data caused by eye blinking, loss of pupil tracking, and/or head movement. Twelve physiologically relevant parameters were extracted from the collected data: (1) baseline diameter, (2) minimum diameter, (3) response amplitude, (4) re-dilation amplitude, (5) percent of baseline diameter, (6) response time, (7) re-dilation time, (8) average constriction velocity, (9) average re-dilation velocity, (10) maximum constriction velocity, (11) maximum re-dilation velocity, and (12) onset latency. No significant differences were noted between parameters derived from algorithm calculated values and manually derived results (p ≥ 0.05). This mathematical algorithm will expedite endpoint data derivation and eliminate human error in the manual calculation of pupillometric parameters from non-filtered, non-calculated pupillometric values. Subsequently, these values can be used as reference metrics for characterizing the natural history of retinal disease. Furthermore, it will be instrumental in the assessment of functional visual recovery in humans and pre-clinical models of retinal degeneration and optic nerve disease following pharmacological or gene-based therapies. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Thermodynamic Cycle and CFD Analyses for Hydrogen Fueled Air-breathing Pulse Detonation Engines

NASA Technical Reports Server (NTRS)

Povinelli, Louis A.; Yungster, Shaye

2002-01-01

This paper presents the results of a thermodynamic cycle analysis of a pulse detonation engine (PDE) using a hydrogen-air mixture at static conditions. The cycle performance results, namely the specific thrust, fuel consumption and impulse are compared to a single cycle CFD analysis for a detonation tube which considers finite rate chemistry. The differences in the impulse values were indicative of the additional performance potential attainable in a PDE.

Finite-element time-domain algorithms for modeling linear Debye and Lorentz dielectric dispersions at low frequencies.

PubMed

Stoykov, Nikolay S; Kuiken, Todd A; Lowery, Madeleine M; Taflove, Allen

2003-09-01

We present what we believe to be the first algorithms that use a simple scalar-potential formulation to model linear Debye and Lorentz dielectric dispersions at low frequencies in the context of finite-element time-domain (FETD) numerical solutions of electric potential. The new algorithms, which permit treatment of multiple-pole dielectric relaxations, are based on the auxiliary differential equation method and are unconditionally stable. We validate the algorithms by comparison with the results of a previously reported method based on the Fourier transform. The new algorithms should be useful in calculating the transient response of biological materials subject to impulsive excitation. Potential applications include FETD modeling of electromyography, functional electrical stimulation, defibrillation, and effects of lightning and impulsive electric shock.

Minimum-domain impulse theory for unsteady aerodynamic force

NASA Astrophysics Data System (ADS)

Kang, L. L.; Liu, L. Q.; Su, W. D.; Wu, J. Z.

2018-01-01

We extend the impulse theory for unsteady aerodynamics from its classic global form to finite-domain formulation then to minimum-domain form and from incompressible to compressible flows. For incompressible flow, the minimum-domain impulse theory raises the finding of Li and Lu ["Force and power of flapping plates in a fluid," J. Fluid Mech. 712, 598-613 (2012)] to a theorem: The entire force with discrete wake is completely determined by only the time rate of impulse of those vortical structures still connecting to the body, along with the Lamb-vector integral thereof that captures the contribution of all the rest disconnected vortical structures. For compressible flows, we find that the global form in terms of the curl of momentum ∇ × (ρu), obtained by Huang [Unsteady Vortical Aerodynamics (Shanghai Jiaotong University Press, 1994)], can be generalized to having an arbitrary finite domain, but the formula is cumbersome and in general ∇ × (ρu) no longer has discrete structures and hence no minimum-domain theory exists. Nevertheless, as the measure of transverse process only, the unsteady field of vorticity ω or ρω may still have a discrete wake. This leads to a minimum-domain compressible vorticity-moment theory in terms of ρω (but it is beyond the classic concept of impulse). These new findings and applications have been confirmed by our numerical experiments. The results not only open an avenue to combine the theory with computation-experiment in wide applications but also reveal a physical truth that it is no longer necessary to account for all wake vortical structures in computing the force and moment.

New results on finite-time parameter identification and synchronization of uncertain complex dynamical networks with perturbation

NASA Astrophysics Data System (ADS)

Zhao, Hui; Zheng, Mingwen; Li, Shudong; Wang, Weiping

2018-03-01

Some existing papers focused on finite-time parameter identification and synchronization, but provided incomplete theoretical analyses. Such works incorporated conflicting constraints for parameter identification, therefore, the practical significance could not be fully demonstrated. To overcome such limitations, the underlying paper presents new results of parameter identification and synchronization for uncertain complex dynamical networks with impulsive effect and stochastic perturbation based on finite-time stability theory. Novel results of parameter identification and synchronization control criteria are obtained in a finite time by utilizing Lyapunov function and linear matrix inequality respectively. Finally, numerical examples are presented to illustrate the effectiveness of our theoretical results.

Properties of Zero-Free Transfer Function Matrices

NASA Astrophysics Data System (ADS)

D. O. Anderson, Brian; Deistler, Manfred

Transfer functions of linear, time-invariant finite-dimensional systems with more outputs than inputs, as arise in factor analysis (for example in econometrics), have, for state-variable descriptions with generic entries in the relevant matrices, no finite zeros. This paper gives a number of characterizations of such systems (and indeed square discrete-time systems with no zeros), using state-variable, impulse response, and matrix-fraction descriptions. Key properties include the ability to recover the input values at any time from a bounded interval of output values, without any knowledge of an initial state, and an ability to verify the no-zero property in terms of a property of the impulse response coefficient matrices. Results are particularized to cases where the transfer function matrix in question may or may not have a zero at infinity or a zero at zero.

Conjugate gradient determination of optimal plane changes for a class of three-impulse transfers between noncoplanar circular orbits

NASA Technical Reports Server (NTRS)

Burrows, R. R.

1972-01-01

A particular type of three-impulse transfer between two circular orbits is analyzed. The possibility of three plane changes is recognized, and the problem is to optimally distribute these plane changes to minimize the sum of the individual impulses. Numerical difficulties and their solution are discussed. Numerical results obtained from a conjugate gradient technique are presented for both the case where the individual plane changes are unconstrained and for the case where they are constrained. Possibly not unexpectedly, multiple minima are found. The techniques presented could be extended to the finite burn case, but primarily the contents are addressed to preliminary mission design and vehicle sizing.

Infinite horizon optimal impulsive control with applications to Internet congestion control

NASA Astrophysics Data System (ADS)

Avrachenkov, Konstantin; Habachi, Oussama; Piunovskiy, Alexey; Zhang, Yi

2015-04-01

We investigate infinite-horizon deterministic optimal control problems with both gradual and impulsive controls, where any finitely many impulses are allowed simultaneously. Both discounted and long-run time-average criteria are considered. We establish very general and at the same time natural conditions, under which the dynamic programming approach results in an optimal feedback policy. The established theoretical results are applied to the Internet congestion control, and by solving analytically and nontrivially the underlying optimal control problems, we obtain a simple threshold-based active queue management scheme, which takes into account the main parameters of the transmission control protocols, and improves the fairness among the connections in a given network.

Multi-channel spatialization systems for audio signals

NASA Technical Reports Server (NTRS)

Begault, Durand R. (Inventor)

1993-01-01

Synthetic head related transfer functions (HRTF's) for imposing reprogrammable spatial cues to a plurality of audio input signals included, for example, in multiple narrow-band audio communications signals received simultaneously are generated and stored in interchangeable programmable read only memories (PROM's) which store both head related transfer function impulse response data and source positional information for a plurality of desired virtual source locations. The analog inputs of the audio signals are filtered and converted to digital signals from which synthetic head related transfer functions are generated in the form of linear phase finite impulse response filters. The outputs of the impulse response filters are subsequently reconverted to analog signals, filtered, mixed, and fed to a pair of headphones.

Multi-channel spatialization system for audio signals

NASA Technical Reports Server (NTRS)

Begault, Durand R. (Inventor)

1995-01-01

Synthetic head related transfer functions (HRTF's) for imposing reprogramable spatial cues to a plurality of audio input signals included, for example, in multiple narrow-band audio communications signals received simultaneously are generated and stored in interchangeable programmable read only memories (PROM's) which store both head related transfer function impulse response data and source positional information for a plurality of desired virtual source locations. The analog inputs of the audio signals are filtered and converted to digital signals from which synthetic head related transfer functions are generated in the form of linear phase finite impulse response filters. The outputs of the impulse response filters are subsequently reconverted to analog signals, filtered, mixed and fed to a pair of headphones.

Comparison principle for impulsive functional differential equations with infinite delays and applications

NASA Astrophysics Data System (ADS)

Li, Xiaodi; Shen, Jianhua; Akca, Haydar; Rakkiyappan, R.

2018-04-01

We introduce the Razumikhin technique to comparison principle and establish some comparison results for impulsive functional differential equations (IFDEs) with infinite delays, where the infinite delays may be infinite time-varying delays or infinite distributed delays. The idea is, under the help of Razumikhin technique, to reduce the study of IFDEs with infinite delays to the study of scalar impulsive differential equations (IDEs) in which the solutions are easy to deal with. Based on the comparison principle, we study the qualitative properties of IFDEs with infinite delays , which include stability, asymptotic stability, exponential stability, practical stability, boundedness, etc. It should be mentioned that the developed results in this paper can be applied to IFDEs with not only infinite delays but also persistent impulsive perturbations. Moreover, even for the special cases of non-impulsive effects or/and finite delays, the criteria prove to be simpler and less conservative than some existing results. Finally, two examples are given to illustrate the effectiveness and advantages of the proposed results.

Minimum impulse trajectories for Mars round trip missions

NASA Technical Reports Server (NTRS)

Horvat, Glen M.; Alexander, Stephen W.

1992-01-01

Data are presented for minimum-impulse earth-Mars round-trip trajectories for the 2010 to 2027 Mars launch opportunities. Round-trip mission times from 120 to 600 days, including a 30-day rendezvous at Mars, for direct trajectories and trajectories utilizing a Venus gravitational assist are considered. Optimal planetary launch and arrival dates and total impulse requirements are based on all maneuvers being performed propulsively with no finite burn or other losses. Direct trajectories have the lowest impulse requirements for shorter mission times and Venus gravitational assist trajectories have the lowest impulse requirements for longer mission times. It is shown that one can depart on trajectories to Mars, beginning with lower energy trajectories to the moon. The fuel savings varies, depending on the final energy level required and on the swingby procedure used. Procedures discussed include single lunar swingbys, double-powered or unpowered lunar swingbys, third lunar flybys a year later, and gravity assists by Venus and earth after the final lunar swingby.

Connecting multimodality in human communication

PubMed Central

Regenbogen, Christina; Habel, Ute; Kellermann, Thilo

2013-01-01

A successful reciprocal evaluation of social signals serves as a prerequisite for social coherence and empathy. In a previous fMRI study we studied naturalistic communication situations by presenting video clips to our participants and recording their behavioral responses regarding empathy and its components. In two conditions, all three channels transported congruent emotional or neutral information, respectively. Three conditions selectively presented two emotional channels and one neutral channel and were thus bimodally emotional. We reported channel-specific emotional contributions in modality-related areas, elicited by dynamic video clips with varying combinations of emotionality in facial expressions, prosody, and speech content. However, to better understand the underlying mechanisms accompanying a naturalistically displayed human social interaction in some key regions that presumably serve as specific processing hubs for facial expressions, prosody, and speech content, we pursued a reanalysis of the data. Here, we focused on two different descriptions of temporal characteristics within these three modality-related regions [right fusiform gyrus (FFG), left auditory cortex (AC), left angular gyrus (AG) and left dorsomedial prefrontal cortex (dmPFC)]. By means of a finite impulse response (FIR) analysis within each of the three regions we examined the post-stimulus time-courses as a description of the temporal characteristics of the BOLD response during the video clips. Second, effective connectivity between these areas and the left dmPFC was analyzed using dynamic causal modeling (DCM) in order to describe condition-related modulatory influences on the coupling between these regions. The FIR analysis showed initially diminished activation in bimodally emotional conditions but stronger activation than that observed in neutral videos toward the end of the stimuli, possibly by bottom-up processes in order to compensate for a lack of emotional information. The DCM analysis instead showed a pronounced top-down control. Remarkably, all connections from the dmPFC to the three other regions were modulated by the experimental conditions. This observation is in line with the presumed role of the dmPFC in the allocation of attention. In contrary, all incoming connections to the AG were modulated, indicating its key role in integrating multimodal information and supporting comprehension. Notably, the input from the FFG to the AG was enhanced when facial expressions conveyed emotional information. These findings serve as preliminary results in understanding network dynamics in human emotional communication and empathy. PMID:24265613

Connecting multimodality in human communication.

PubMed

Regenbogen, Christina; Habel, Ute; Kellermann, Thilo

2013-01-01

A successful reciprocal evaluation of social signals serves as a prerequisite for social coherence and empathy. In a previous fMRI study we studied naturalistic communication situations by presenting video clips to our participants and recording their behavioral responses regarding empathy and its components. In two conditions, all three channels transported congruent emotional or neutral information, respectively. Three conditions selectively presented two emotional channels and one neutral channel and were thus bimodally emotional. We reported channel-specific emotional contributions in modality-related areas, elicited by dynamic video clips with varying combinations of emotionality in facial expressions, prosody, and speech content. However, to better understand the underlying mechanisms accompanying a naturalistically displayed human social interaction in some key regions that presumably serve as specific processing hubs for facial expressions, prosody, and speech content, we pursued a reanalysis of the data. Here, we focused on two different descriptions of temporal characteristics within these three modality-related regions [right fusiform gyrus (FFG), left auditory cortex (AC), left angular gyrus (AG) and left dorsomedial prefrontal cortex (dmPFC)]. By means of a finite impulse response (FIR) analysis within each of the three regions we examined the post-stimulus time-courses as a description of the temporal characteristics of the BOLD response during the video clips. Second, effective connectivity between these areas and the left dmPFC was analyzed using dynamic causal modeling (DCM) in order to describe condition-related modulatory influences on the coupling between these regions. The FIR analysis showed initially diminished activation in bimodally emotional conditions but stronger activation than that observed in neutral videos toward the end of the stimuli, possibly by bottom-up processes in order to compensate for a lack of emotional information. The DCM analysis instead showed a pronounced top-down control. Remarkably, all connections from the dmPFC to the three other regions were modulated by the experimental conditions. This observation is in line with the presumed role of the dmPFC in the allocation of attention. In contrary, all incoming connections to the AG were modulated, indicating its key role in integrating multimodal information and supporting comprehension. Notably, the input from the FFG to the AG was enhanced when facial expressions conveyed emotional information. These findings serve as preliminary results in understanding network dynamics in human emotional communication and empathy.

Comparison of fMRI analysis methods for heterogeneous BOLD responses in block design studies

PubMed Central

Bernal-Casas, David; Fang, Zhongnan; Lee, Jin Hyung

2017-01-01

A large number of fMRI studies have shown that the temporal dynamics of evoked BOLD responses can be highly heterogeneous. Failing to model heterogeneous responses in statistical analysis can lead to significant errors in signal detection and characterization and alter the neurobiological interpretation. However, to date it is not clear that, out of a large number of options, which methods are robust against variability in the temporal dynamics of BOLD responses in block-design studies. Here, we used rodent optogenetic fMRI data with heterogeneous BOLD responses and simulations guided by experimental data as a means to investigate different analysis methods’ performance against heterogeneous BOLD responses. Evaluations are carried out within the general linear model (GLM) framework and consist of standard basis sets as well as independent component analysis (ICA). Analyses show that, in the presence of heterogeneous BOLD responses, conventionally used GLM with a canonical basis set leads to considerable errors in the detection and characterization of BOLD responses. Our results suggest that the 3rd and 4th order gamma basis sets, the 7th to 9th order finite impulse response (FIR) basis sets, the 5th to 9th order B-spline basis sets, and the 2nd to 5th order Fourier basis sets are optimal for good balance between detection and characterization, while the 1st order Fourier basis set (coherence analysis) used in our earlier studies show good detection capability. ICA has mostly good detection and characterization capabilities, but detects a large volume of spurious activation with the control fMRI data. PMID:27993672

Microseism Induced by Transient Release of In Situ Stress During Deep Rock Mass Excavation by Blasting

NASA Astrophysics Data System (ADS)

Yang, Jianhua; Lu, Wenbo; Chen, Ming; Yan, Peng; Zhou, Chuangbing

2013-07-01

During deep rock mass excavation with the method of drill and blast, accompanying the secession of rock fragments and the formation of a new free surface, in situ stress on this boundary is suddenly released within several milliseconds, which is termed the transient release of in situ stress. In this process, enormous strain energy around the excavation face is instantly released in the form of kinetic energy and it inevitably induces microseismic events in surrounding rock masses. Thus, blasting excavation-induced microseismic vibrations in high-stress rock masses are attributed to the combined action of explosion and the transient release of in situ stress. The intensity of stress release-induced microseisms, which depends mainly on the magnitude of the in situ stress and the dimension of the excavation face, is comparable to that of explosion-induced vibrations. With the methods of time-energy density analysis, amplitude spectrum analysis, and finite impulse response (FIR) digital filter, microseismic vibrations induced by the transient release of in situ stress were identified and separated from recorded microseismic signals during a blast of deep rock masses in the Pubugou Hydropower Station. The results show that the low-frequency component in the microseismic records results mainly from the transient release of in situ stress, while the high-frequency component originates primarily from explosion. In addition, a numerical simulation was conducted to demonstrate the occurrence of microseismic events by the transient release of in situ stress, and the results seem to have confirmed fairly well the separated vibrations from microseismic records.

An adaptive vibration control method to suppress the vibration of the maglev train caused by track irregularities

NASA Astrophysics Data System (ADS)

Zhou, Danfeng; Yu, Peichang; Wang, Lianchun; Li, Jie

2017-11-01

The levitation gap of the urban maglev train is around 8 mm, which puts a rather high requirement on the smoothness of the track. In practice, it is found that the track irregularity may cause stability problems when the maglev train is traveling. In this paper, the dynamic response of the levitation module, which is the basic levitation structure of the urban maglev train, is investigated in the presence of track irregularities. Analyses show that due to the structural configuration of the levitation module, the vibration of the levitation gap may be amplified and "resonances" may be observed under some specified track wavelengths and train speeds; besides, it is found that the gap vibration of the rear levitation unit in a levitation module is more significant than that of the front levitation unit, which agrees well with practice. To suppress the vibration of the rear levitation gap, an adaptive vibration control method is proposed, which utilizes the information of the front levitation unit as a reference. A pair of mirror FIR (finite impulse response) filters are designed and tuned by an adaptive mechanism, and they produce a compensation signal for the rear levitation controller to cancel the disturbance brought by the track irregularity. Simulations under some typical track conditions, including the sinusoidal track profile, random track irregularity, as well as track steps, indicate that the adaptive vibration control scheme can significantly reduce the amplitude of the rear gap vibration, which provides a method to improve the stability and ride comfort of the maglev train.

A new design approach to MMI-based (de)multiplexers

NASA Astrophysics Data System (ADS)

Yueyu, Xiao; Sailing, He

2004-09-01

A novel design method of the wavelength (de)multiplexer is presented. The output spectral response of a (de)multiplexer is designed from the view of FIR filters. Avoiding laborious mathematic analysis, the (de)multiplexer is analyzed and designed in this explicit and simple method. A four channel (de)multiplexer based on multimode interference (MMI) is designed as an example. The result obtained agrees with that of the commonly used method, and is verified by a finite difference beam propagation method (FDBPM) simulation.

Annual Review of Research Under the Joint Services Electronics Program.

DTIC Science & Technology

1983-12-01

Total Number of Professionals: PI 2 RA 2 (1/2 time ) 6. Sunmmary: Our research into the theory of nonlinear control systems and appli- * cations to...known that all linear time -invariant controllable systems can be transformed to Brunovsky canonical form by a transformation consist- ing only of...estimating the impulse response ( = transfer matrix) of a discrete- time linear system x(t+l) = Fx(t) + Gu(t) y(t) = Hx(t) from a finite set of finite

Spacecraft formation control using analytical finite-duration approaches

NASA Astrophysics Data System (ADS)

Ben Larbi, Mohamed Khalil; Stoll, Enrico

2018-03-01

This paper derives a control concept for formation flight (FF) applications assuming circular reference orbits. The paper focuses on a general impulsive control concept for FF which is then extended to the more realistic case of non-impulsive thrust maneuvers. The control concept uses a description of the FF in relative orbital elements (ROE) instead of the classical Cartesian description since the ROE provide a direct insight into key aspects of the relative motion and are particularly suitable for relative orbit control purposes and collision avoidance analysis. Although Gauss' variational equations have been first derived to offer a mathematical tool for processing orbit perturbations, they are suitable for several different applications. If the perturbation acceleration is due to a control thrust, Gauss' variational equations show the effect of such a control thrust on the Keplerian orbital elements. Integrating the Gauss' variational equations offers a direct relation between velocity increments in the local vertical local horizontal frame and the subsequent change of Keplerian orbital elements. For proximity operations, these equations can be generalized from describing the motion of single spacecraft to the description of the relative motion of two spacecraft. This will be shown for impulsive and finite-duration maneuvers. Based on that, an analytical tool to estimate the error induced through impulsive maneuver planning is presented. The resulting control schemes are simple and effective and thus also suitable for on-board implementation. Simulations show that the proposed concept improves the timing of the thrust maneuver executions and thus reduces the residual error of the formation control.

The Nonlinear Dynamic Response of an Elastic-Plastic Thin Plate under Impulsive Loading,

DTIC Science & Technology

1987-06-11

Among those numerical methods, the finite element method is the most effective one. The method presented in this paper is an " influence function " numerical...computational time is much less than the finite element method. Its precision is higher also. II. Basic Assumption and the Influence Function of a Simple...calculation. Fig. 1 3 2. The Influence function of a Simple Supported Plate The motion differential equation of a thin plate can be written as DV’w+ _.eluq() (1

Numerical Analysis of the Bending Properties of Cathay Poplar Glulam

PubMed Central

Gao, Ying; Wu, Yuxuan; Zhu, Xudong; Zhu, Lei; Yu, Zhiming; Wu, Yong

2015-01-01

This paper presents the formulae and finite element analysis models for predicting the Modulus of Elastic (MOE) and Modulus of Rupture (MOR) of Cathay poplar finger-jointed glulam. The formula of the MOE predicts the MOE of Cathay poplar glulam glued with one-component polyurethane precisely. Three formulae are used to predict the MOR, and Equation (12) predicts the MOR of Cathay poplar glulam precisely. The finite element analysis simulation results of both the MOE and MOR are similar to the experimental results. The predicted results of the finite element analysis are shown to be more accurate than those of the formulae, because the finite element analysis considers the glue layers, but the formulae do not. Three types of typical failure modes due to bending were summarized. The bending properties of Cathay poplar glulam were compared to those of Douglas fir glulam. The results show that Cathay poplar glulam has a lower stiffness, but a marginally higher strength. One-component polyurethane adhesive is shown to be more effective than resorcinol formaldehyde resin adhesive for Cathay poplar glulam. This study shows that Cathay poplar has the potential to be a glulam material in China. PMID:28793619

Wearable Sensor Data Classification for Human Activity Recognition Based on an Iterative Learning Framework.

PubMed

Davila, Juan Carlos; Cretu, Ana-Maria; Zaremba, Marek

2017-06-07

The design of multiple human activity recognition applications in areas such as healthcare, sports and safety relies on wearable sensor technologies. However, when making decisions based on the data acquired by such sensors in practical situations, several factors related to sensor data alignment, data losses, and noise, among other experimental constraints, deteriorate data quality and model accuracy. To tackle these issues, this paper presents a data-driven iterative learning framework to classify human locomotion activities such as walk, stand, lie, and sit, extracted from the Opportunity dataset. Data acquired by twelve 3-axial acceleration sensors and seven inertial measurement units are initially de-noised using a two-stage consecutive filtering approach combining a band-pass Finite Impulse Response (FIR) and a wavelet filter. A series of statistical parameters are extracted from the kinematical features, including the principal components and singular value decomposition of roll, pitch, yaw and the norm of the axial components. The novel interactive learning procedure is then applied in order to minimize the number of samples required to classify human locomotion activities. Only those samples that are most distant from the centroids of data clusters, according to a measure presented in the paper, are selected as candidates for the training dataset. The newly built dataset is then used to train an SVM multi-class classifier. The latter will produce the lowest prediction error. The proposed learning framework ensures a high level of robustness to variations in the quality of input data, while only using a much lower number of training samples and therefore a much shorter training time, which is an important consideration given the large size of the dataset.

Comparison of fMRI analysis methods for heterogeneous BOLD responses in block design studies.

PubMed

Liu, Jia; Duffy, Ben A; Bernal-Casas, David; Fang, Zhongnan; Lee, Jin Hyung

2017-02-15

A large number of fMRI studies have shown that the temporal dynamics of evoked BOLD responses can be highly heterogeneous. Failing to model heterogeneous responses in statistical analysis can lead to significant errors in signal detection and characterization and alter the neurobiological interpretation. However, to date it is not clear that, out of a large number of options, which methods are robust against variability in the temporal dynamics of BOLD responses in block-design studies. Here, we used rodent optogenetic fMRI data with heterogeneous BOLD responses and simulations guided by experimental data as a means to investigate different analysis methods' performance against heterogeneous BOLD responses. Evaluations are carried out within the general linear model (GLM) framework and consist of standard basis sets as well as independent component analysis (ICA). Analyses show that, in the presence of heterogeneous BOLD responses, conventionally used GLM with a canonical basis set leads to considerable errors in the detection and characterization of BOLD responses. Our results suggest that the 3rd and 4th order gamma basis sets, the 7th to 9th order finite impulse response (FIR) basis sets, the 5th to 9th order B-spline basis sets, and the 2nd to 5th order Fourier basis sets are optimal for good balance between detection and characterization, while the 1st order Fourier basis set (coherence analysis) used in our earlier studies show good detection capability. ICA has mostly good detection and characterization capabilities, but detects a large volume of spurious activation with the control fMRI data. Copyright © 2016 Elsevier Inc. All rights reserved.

Neural activity in the hippocampus predicts individual visual short-term memory capacity.

PubMed

von Allmen, David Yoh; Wurmitzer, Karoline; Martin, Ernst; Klaver, Peter

2013-07-01

Although the hippocampus had been traditionally thought to be exclusively involved in long-term memory, recent studies raised controversial explanations why hippocampal activity emerged during short-term memory tasks. For example, it has been argued that long-term memory processes might contribute to performance within a short-term memory paradigm when memory capacity has been exceeded. It is still unclear, though, whether neural activity in the hippocampus predicts visual short-term memory (VSTM) performance. To investigate this question, we measured BOLD activity in 21 healthy adults (age range 19-27 yr, nine males) while they performed a match-to-sample task requiring processing of object-location associations (delay period  =  900 ms; set size conditions 1, 2, 4, and 6). Based on individual memory capacity (estimated by Cowan's K-formula), two performance groups were formed (high and low performers). Within whole brain analyses, we found a robust main effect of "set size" in the posterior parietal cortex (PPC). In line with a "set size × group" interaction in the hippocampus, a subsequent Finite Impulse Response (FIR) analysis revealed divergent hippocampal activation patterns between performance groups: Low performers (mean capacity  =  3.63) elicited increased neural activity at set size two, followed by a drop in activity at set sizes four and six, whereas high performers (mean capacity  =  5.19) showed an incremental activity increase with larger set size (maximal activation at set size six). Our data demonstrated that performance-related neural activity in the hippocampus emerged below capacity limit. In conclusion, we suggest that hippocampal activity reflected successful processing of object-location associations in VSTM. Neural activity in the PPC might have been involved in attentional updating. Copyright © 2013 Wiley Periodicals, Inc.

Matched filter based detection of floating mines in IR spacetime

NASA Astrophysics Data System (ADS)

Borghgraef, Alexander; Lapierre, Fabian; Philips, Wilfried; Acheroy, Marc

2009-09-01

Ship-based automatic detection of small floating objects on an agitated sea surface remains a hard problem. Our main concern is the detection of floating mines, which proved a real threat to shipping in confined waterways during the first Gulf War, but applications include salvaging,search-and-rescue and perimeter or harbour defense. IR video was chosen for its day-and-night imaging capability, and its availability on military vessels. Detection is difficult because a rough sea is seen as a dynamic background of moving objects with size order, shape and temperature similar to those of the floating mine. We do find a determinant characteristic in the target's periodic motion, which differs from that of the propagating surface waves composing the background. The classical detection and tracking approaches give bad results when applied to this problem. While background detection algorithms assume a quasi-static background, the sea surface is actually very dynamic, causing this category of algorithms to fail. Kalman or particle filter algorithms on the other hand, which stress temporal coherence, suffer from tracking loss due to occlusions and the great noise level of the image. We propose an innovative approach. This approach uses the periodicity of the objects movement and thus its temporal coherence. The principle is to consider the video data as a spacetime volume similar to a hyperspectral data cube by replacing the spectral axis with a temporal axis. We can then apply algorithms developed for hyperspectral detection problems to the detection of small floating objects. We treat the detection problem using multilinear algebra, designing a number of finite impulse response filters (FIR) maximizing the target response. The algorithm was applied to test footage of practice mines in the infrared.

Design and testing of a controlled electromagnetic spinal cord impactor for use in large animal models of acute traumatic spinal cord injury.

PubMed

Petteys, Rory J; Spitz, Steven M; Syed, Hasan; Rice, R Andrew; Sarabia-Estrada, Rachel; Goodwin, C Rory; Sciubba, Daniel M; Freedman, Brett A

2017-09-01

Spinal cord injury (SCI) causes debilitating neurological dysfunction and has been observed in warfighters injured in IED blasts. Clinical benefit of SCI treatment remains elusive and better large animal models are needed to assess treatment options. Here, we describe a controlled electromagnetic spinal cord impactor for use in large animal models of SCI. A custom spinal cord impactor and platform were fabricated for large animals (e.g., pig, sheep, dog, etc.). Impacts were generated by a voice coil actuator; force and displacement were measured with a load cell and potentiometer respectively. Labview (National Instruments, Austin, TX) software was used to control the impact cycle and import force and displacement data. Software finite impulse response (FIR) filtering was employed for all input data. Silicon tubing was used a surrogate for spinal cord in order to test the device; repeated impacts were performed at 15, 25, and 40 Newtons. Repeated impacts demonstrated predictable results at each target force. The average duration of impact was 71.2 ±6.1ms. At a target force of 40N, the output force was 41.5 ±0.7N. With a target of 25N, the output force was 23.5 ±0.6N; a target of 15Newtons revealed an output force of 15.2 ±1.4N. The calculated acceleration range was 12.5-21.2m/s 2 . This custom spinal cord impactor reliably delivers precise impacts to the spinal cord and will be utilized in future research to study acute traumatic SCI in a large animal. Published by Elsevier Ltd.

Experiences with digital processing of images at INPE

NASA Technical Reports Server (NTRS)

Mascarenhas, N. D. A. (Principal Investigator)

1984-01-01

Four different research experiments with digital image processing at INPE will be described: (1) edge detection by hypothesis testing; (2) image interpolation by finite impulse response filters; (3) spatial feature extraction methods in multispectral classification; and (4) translational image registration by sequential tests of hypotheses.

Using indicator plants to assess susceptibility of Californian red fir and white fir to the fir engraver beetle

Treesearch

George T. Ferrell

1986-01-01

Using a Vegetation Drought Index (VDI) for estimating the susceptibility of California red and white firs to the fir engraver beetle (Scolytus venttralis) was evaluated in northern California forests where these true firs (Abies species) occur in mixed conifer and true fir stands. Midway through the summer drought, true fir...

Impulse Magnetization of Nd-Fe-B Sintered Magnets for Sensors

PubMed Central

Przybylski, Marek; Kapelski, Dariusz; Ślusarek, Barbara; Wiak, Sławomir

2016-01-01

Magnetization of large Nd-Fe-B sintered permanent magnets is still challenging. This type of permanent magnet is electrically conductive, so impulse magnetization causes a flow of eddy currents which prevent magnetization of the whole volume of the magnet. The paper deals with the impulse magnetization of sintered Nd-Fe-B permanent magnets and shows a method for the determination of suitable parameters for the supply system. The necessary magnetic field strength for magnetization of the magnet to saturation was determined. The optimal magnetizing fixture supply voltage for magnetization to saturation was determined from simulations in PSpice software, finite element analyses in Maxwell 15 and measurements. Measurements of magnetic induction on the surface of the Nd-Fe-B magnet are also presented to ensure that a magnet with 70 mm diameter and 20 mm in height is fully saturated. PMID:27110783

Impulse Magnetization of Nd-Fe-B Sintered Magnets for Sensors.

PubMed

Przybylski, Marek; Kapelski, Dariusz; Ślusarek, Barbara; Wiak, Sławomir

2016-04-21

Magnetization of large Nd-Fe-B sintered permanent magnets is still challenging. This type of permanent magnet is electrically conductive, so impulse magnetization causes a flow of eddy currents which prevent magnetization of the whole volume of the magnet. The paper deals with the impulse magnetization of sintered Nd-Fe-B permanent magnets and shows a method for the determination of suitable parameters for the supply system. The necessary magnetic field strength for magnetization of the magnet to saturation was determined. The optimal magnetizing fixture supply voltage for magnetization to saturation was determined from simulations in PSpice software, finite element analyses in Maxwell 15 and measurements. Measurements of magnetic induction on the surface of the Nd-Fe-B magnet are also presented to ensure that a magnet with 70 mm diameter and 20 mm in height is fully saturated.

Mapping interictal epileptic discharges using mutual information between concurrent EEG and fMRI.

PubMed

Caballero-Gaudes, César; Van de Ville, Dimitri; Grouiller, Frédéric; Thornton, Rachel; Lemieux, Louis; Seeck, Margitta; Lazeyras, François; Vulliemoz, Serge

2013-03-01

The mapping of haemodynamic changes related to interictal epileptic discharges (IED) in simultaneous electroencephalography (EEG) and functional MRI (fMRI) studies is usually carried out by means of EEG-correlated fMRI analyses where the EEG information specifies the model to test on the fMRI signal. The sensitivity and specificity critically depend on the accuracy of EEG detection and the validity of the haemodynamic model. In this study we investigated whether an information theoretic analysis based on the mutual information (MI) between the presence of epileptic activity on EEG and the fMRI data can provide further insights into the haemodynamic changes related to interictal epileptic activity. The important features of MI are that: 1) both recording modalities are treated symmetrically; 2) no requirement for a-priori models for the haemodynamic response function, or assumption of a linear relationship between the spiking activity and BOLD responses, and 3) no parametric model for the type of noise or its probability distribution is necessary for the computation of MI. Fourteen patients with pharmaco-resistant focal epilepsy underwent EEG-fMRI and intracranial EEG and/or surgical resection with positive postoperative outcome (seizure freedom or considerable reduction in seizure frequency) was available in 7/14 patients. We used nonparametric statistical assessment of the MI maps based on a four-dimensional wavelet packet resampling method. The results of MI were compared to the statistical parametric maps obtained with two conventional General Linear Model (GLM) analyses based on the informed basis set (canonical HRF and its temporal and dispersion derivatives) and the Finite Impulse Response (FIR) models. The MI results were concordant with the electro-clinically or surgically defined epileptogenic area in 8/14 patients and showed the same degree of concordance as the results obtained with the GLM-based methods in 12 patients (7 concordant and 5 discordant). In one patient, the information theoretic analysis improved the delineation of the irritative zone compared with the GLM-based methods. Our findings suggest that an information theoretic analysis can provide clinically relevant information about the BOLD signal changes associated with the generation and propagation of interictal epileptic discharges. The concordance between the MI, GLM and FIR maps support the validity of the assumptions adopted in GLM-based analyses of interictal epileptic activity with EEG-fMRI in such a manner that they do not significantly constrain the localization of the epileptogenic zone. Copyright © 2012 Elsevier Inc. All rights reserved.

Qualitative analysis of MTEM response using instantaneous attributes

NASA Astrophysics Data System (ADS)

Fayemi, Olalekan; Di, Qingyun

2017-11-01

This paper introduces new technique for qualitative analysis of multi-transient electromagnetic (MTEM) earth impulse response over complex geological structures. Instantaneous phase and frequency attributes were used in place of the conventional common offset section for improved qualitative interpretation of MTEM data by obtaining more detailed information from the earth impulse response. The instantaneous attributes were used to describe the lateral variation in subsurface resistivity and the visible geological structure with respect to given offsets. Instantaneous phase attribute was obtained by converting the impulse response into a complex form using the Hilbert transform. Conversely, the polynomial phase difference (PPD) estimator was favored over the center finite difference (CFD) approximation method in calculating the instantaneous frequency attribute because it is computationally efficient and has the ability to give a smooth variation of the instantaneous frequency over a common offset section. The observed results from the instantaneous attributes were in good agreement with both the subsurface model used and the apparent resistivity section obtained from the MTEM earth impulse response. Hence, this study confirms the capability of both instantaneous phase and frequency attributes as highly effective tools for MTEM qualitative analysis.

Rooting cuttings from douglas-fir, white-fir, and California red fir christmas trees

Treesearch

C. M. Blankensop; R. Z. Callaham

1960-01-01

Christmas tree growers in California have asked geneticists to help improve the characteristics of the - wild species they are cultivating. The preferred Christmas trees of California are Shasta red fir (Abies magnifica A. Murr.), white fir (A. concolor (Gord. & Glend.) Lindl.), and Douglas-fir (Pseudotsuga...

Non-transmissible Sendai virus vector encoding c-myc suppressor FBP-interacting repressor for cancer therapy

PubMed Central

Matsushita, Kazuyuki; Shimada, Hideaki; Ueda, Yasuji; Inoue, Makoto; Hasegawa, Mamoru; Tomonaga, Takeshi; Matsubara, Hisahiro; Nomura, Fumio

2014-01-01

AIM: To investigate a novel therapeutic strategy to target and suppress c-myc in human cancers using far up stream element (FUSE)-binding protein-interacting repressor (FIR). METHODS: Endogenous c-Myc suppression and apoptosis induction by a transient FIR-expressing vector was examined in vivo via a HA-tagged FIR (HA-FIR) expression vector. A fusion gene-deficient, non-transmissible, Sendai virus (SeV) vector encoding FIR cDNA, SeV/dF/FIR, was prepared. SeV/dF/FIR was examined for its gene transduction efficiency, viral dose dependency of antitumor effect and apoptosis induction in HeLa (cervical squamous cell carcinoma) cells and SW480 (colon adenocarcinoma) cells. Antitumor efficacy in a mouse xenograft model was also examined. The molecular mechanism of the anti-tumor effect and c-Myc suppression by SeV/dF/FIR was examined using Spliceostatin A (SSA), a SAP155 inhibitor, or SAP155 siRNA which induce c-Myc by increasing FIR∆exon2 in HeLa cells. RESULTS: FIR was found to repress c-myc transcription and in turn the overexpression of FIR drove apoptosis through c-myc suppression. Thus, FIR expressing vectors are potentially applicable for cancer therapy. FIR is alternatively spliced by SAP155 in cancer cells lacking the transcriptional repression domain within exon 2 (FIR∆exon2), counteracting FIR for c-Myc protein expression. Furthermore, FIR forms a complex with SAP155 and inhibits mutual well-established functions. Thus, both the valuable effects and side effects of exogenous FIR stimuli should be tested for future clinical application. SeV/dF/FIR, a cytoplasmic RNA virus, was successfully prepared and showed highly efficient gene transduction in in vivo experiments. Furthermore, in nude mouse tumor xenograft models, SeV/dF/FIR displayed high antitumor efficiency against human cancer cells. SeV/dF/FIR suppressed SSA-activated c-Myc. SAP155 siRNA, potentially produces FIR∆exon2, and led to c-Myc overexpression with phosphorylation at Ser62. HA-FIR suppressed endogenous c-Myc expression and induced apoptosis in HeLa and SW480 cells. A c-myc transcriptional suppressor FIR expressing SeV/dF/FIR showed high gene transduction efficiency with significant antitumor effects and apoptosis induction in HeLa and SW480 cells. CONCLUSION: SeV/dF/FIR showed strong tumor growth suppression with no significant side effects in an animal xenograft model, thus SeV/dF/FIR is potentially applicable for future clinical cancer treatment. PMID:24764668

Price projections for selected grades of Douglas-fir, coast hem-fir, inland hem-fir, and ponderosa pine lumber.

Treesearch

Richard W. Haynes; Roger D. Fight

1992-01-01

Grade-specific price projections were developed for Douglas-fir, coast hem-fir, inland hem-fir, and ponderosa pine lumber. These grade-specific price projections can be used in evaluating management practices that will affect the quality of saw logs produced under various management regimes.

Weather and tree growth associated with white fir mortality caused by fir engraver and roundheaded fir borer

Treesearch

George T. Ferrell; Ralph C. Hall

1975-01-01

White fir (Abides concolor [Cord. & Glend.] Lindl.) stands in Western North America periodically suffer extensive tree mortality caused by outbreaks of the fir engraver bark beetle (Scolytus ventralis Lec.). The cambial zone of the boles infested by S. ventralis is also colonized by the roundheaded fir borer...

Silvics of grand fir

Treesearch

Marvin W. Foiles

1959-01-01

Grand fir (Abies grandis) is one of the two balsam firs found in the northern Rocky Mountain region and one of seven in the Pacific Northwest. Except in the southern part of its range, where it is often confused with white fir (Abies concolor), it is distinguished from other firs in its range by its needles, which are distinctly two-ranked. Grand fir differs...

Growth classification systems for red fir and white fir in northern California

Treesearch

George T. Ferrell

1983-01-01

Selected crown and bole characteristics were predictor variables in growth classification equations developed for California red fir, Shasta red fir, and white fir in northern California. Individual firs were classified on the basis of percent basal area increment (PCTBAI ) as Class 1 (≤ 1 pct), Class 2 (> 1 pct and ≤ 3 pct), or Class 3 (> 3...

Fir dwarf mistletoe (FIDL).

Treesearch

Gregory M. Filip; Jerome S. Beatty; Robert L. Mathiasen

2000-01-01

Fir dwarf mistletoe (Arceuthobium abietinum Engelmann ex Munz) is a common and damaging parasite of white fir (Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.), grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), and California red fir (A. magnifica A. Murr.) in the western...

Damage from wind and other causes in mixed white fir-red fir stands adjacent to clearcuttings

Treesearch

Donald T. Gordon

1973-01-01

Damage to timber surrounding clearcuttings and in one light selection cutting in mixed white fir-red fir stands was monitored for 6 years in northeastern California. In some years, bark beetles apparently killed more trees than did wind damage, but in two of the study years, severe wind storms caused much damage. One storm produced mainly break-age, apparently...

Radial growth of grand fir and Douglas-fir 10 years after defoliation by the Douglas-fir tussock moth in the Blue Mountains outbreak.

Treesearch

Boyd E. Wickman

1986-01-01

Radial-growth recovery related to amount of tree defoliation was measured 10 years after a severe outbreak of Douglas-fir tussock moth (Orgyia pseudotsugata (McDunnough). For the period 1978-82, growth of qrand fir surpassed and was significantly greater than in the preoutbreak period, 1968-72. Douglas-fir growth during the postoutbreak period...

Reconsidering price projections for selected grades of Douglas-fir, coast hem-fir, inland hem-fir, and ponderosa pine lumber.

Treesearch

Richard W. Haynes; Roger D. Fight

2004-01-01

Grade-specific price projections were once again developed for Douglas-fir, coast hem-fir, inland hem-fir, and ponderosa pine lumber. These grade-specific price projections can be used to demonstrate the returns to land management of practices that lead to high-quality logs that produce a larger proportion of high grades of lumber. The price ratios among low, medium,...

Douglas-fir tussock moth- and Douglas-fir beetle-caused mortality in a ponderosa pine/Douglas-fir forest in the Colorado Front Range, USA

Treesearch

Jose F. Negron; Ann M. Lynch; Willis C. Schaupp; Vladimir Bocharnikov

2014-01-01

An outbreak of the Douglas-fir tussock moth, Orgyia pseudotsugata McDunnough, occurred in the South Platte River drainage on the Pike-San Isabel National Forest in the Colorado Front Range attacking Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco. Stocking levels, species composition, and tree size in heavily and lightly defoliated stands were similar. Douglas-fir...

AmeriFlux CA-Na1 New Brunswick - 1967 Balsam Fir - Nashwaak Lake Site 01 (Mature balsam fir forest)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bourque, Charles P.-A.

This is the AmeriFlux version of the carbon flux data for the site CA-Na1 New Brunswick - 1967 Balsam Fir - Nashwaak Lake Site 01 (Mature balsam fir forest). Site Description - immature balsam fir forest

Development and Implementation of a Scramjet Cycle Analysis Code with a Finite-Rate-Chemistry Combustion Model for Use on a Personal Computer

DTIC Science & Technology

1993-12-01

2 3 9 V List of Fi-ures Figure 1 - Functional...Block Diagram of a Scramjet ........................................ 9 Figure 2 - ’Corrected’ Specific Impulse of Hydrogen-Oxygen Rocket ............. 35...38 Figure 8 - Schematic of Northam/Anderson Mixing Model ............................ 39 Figure 9 - Pressure-Area

Prediction of high-speed rotor noise with a Kirchhoff formula

NASA Technical Reports Server (NTRS)

Purcell, Timothy W.; Strawn, Roger C.; Yu, Yung H.

1987-01-01

A new methodology has been developed to predict the impulsive noise generated by a transonic rotor blade. The formulation uses a full-potential finite-difference method to obtain the pressure field close to the blade. A Kirchhoff integral formulation is then used to extend these finite-difference results into the far-field. This Kirchhoff formula is written in a blade-fixed coordinate system. It requires initial data across a plane at the sonic radius. This data is provided by the finite-difference solution. Acoustic pressure predictions show excellent agreement with hover experimental data for two hover cases of 0.88 and 0.90 tip Mach number, the latter of which has delocalized transonic flow. These results represent the first successful prediction technique for peak pressure amplitudes using a computational code.

Fir Engraver (FIDL)

Treesearch

George T. Ferrell

1986-01-01

The fir engraver, Scolytus ventralis LeConte, belongs to the family of insects called bark beetles, which live between the bark and wood of host trees. A wide-ranging, native beetle, the fir engraver attacks most species of fir in the Western United States. Epidemics can cause severe tree mortality. From 1977 to 1978, for example, the fir engraver killed an estimated 1...

Heart Rots of Red and White Firs

Treesearch

J.W. Kimmey; H.H. Jr. Bynum

1961-01-01

Heart rots, caused by fungi that attack the heartwood of living trees, are responsible for the greatest volume loss sustained by California red fir (Abies magnifica A. Murr.) and white fir (A. concolor (Gord. and Glend.) Lindl.). These two firs comprise 25 percent of the commercial timber of California. More than 13 percent of the volume in these firs is useless cull...

The identification of Douglas-fir wood

Treesearch

Forest Products Laboratory (U.S.)

1963-01-01

Douglas-fir is one of the largest, most abundant and widely distributed species of trees native to North America, and next to the southern yellow pines, it is cut in the greatest quantities of any wood of commercial importance. It belongs to the coniferous family and is, therefore, a softwood. Other names for Douglas -fir are red fir, yellow fir, Oregon pine, Puget...

Weather, logging, and tree growth associated with fir engraver attack scars in white fir

Treesearch

George T. Ferrell

1973-01-01

The boles of 32 recently killed, and 41 living, white fir were examined for embedded fir engraver (Scolytus ventralis) attack scars. Of 287 scars found in annual rings for the years 1934-69, only 2 to 3 percent represented reproductively successful attacks. Trends in scar abundance were directly correlated with trends in white fir killed by ...

Concomitant expression of far upstream element (FUSE) binding protein (FBP) interacting repressor (FIR) and its splice variants induce migration and invasion of non-small cell lung cancer (NSCLC) cells.

PubMed

Müller, Benedikt; Bovet, Michael; Yin, Yi; Stichel, Damian; Malz, Mona; González-Vallinas, Margarita; Middleton, Alistair; Ehemann, Volker; Schmitt, Jennifer; Muley, Thomas; Meister, Michael; Herpel, Esther; Singer, Stephan; Warth, Arne; Schirmacher, Peter; Drasdo, Dirk; Matthäus, Franziska; Breuhahn, Kai

2015-11-01

Transcription factors integrate a variety of oncogenic input information, facilitate tumour growth and cell dissemination, and therefore represent promising therapeutic target structures. Because over-expression of DNA-interacting far upstream element binding protein (FBP) supports non-small cell lung cancer (NSCLC) migration, we asked whether its repressor, FBP-interacting repressor (FIR) is functionally inactivated and how FIR might affect NSCLC cell biology. Different FIR splice variants were highly expressed in the majority of NSCLCs, with the highest levels in tumours carrying genomic gains of chromosome 8q24.3, which contained the FIR gene locus. Nuclear FIR expression was significantly enriched at the invasion front of primary NSCLCs, but this did not correlate with tumour cell proliferation. FIR accumulation was associated with worse patient survival and tumour recurrence; in addition, FIR over-expression significantly correlated with lymph node metastasis in squamous cell carcinomas (SCCs). In vitro, we applied newly developed methods and modelling approaches for the quantitative and time-resolved description of the pro-migratory and pro-invasive capacities of SCC cells. siRNA-mediated silencing of all FIR variants significantly reduced the speed and directional movement of tumour cells in all phases of migration. Furthermore, sprouting efficiency and single cell invasiveness were diminished following FIR inhibition. Interestingly, the silencing of FIR isoforms lacking exon 2 (FIR(Δexon2)) alone was sufficient to reduce lateral migration and invasion. In summary, by using scale-spanning data derived from primary human tissues, quantitative cellular analyses and mathematical modelling, we have demonstrated that concomitant over-expression of FIR and its splice variants drives NSCLC migration and dissemination. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Finite-element nonlinear transient response computer programs PLATE 1 and CIVM-PLATE 1 for the analysis of panels subjected to impulse or impact loads

NASA Technical Reports Server (NTRS)

Spilker, R. L.; Witmer, E. A.; French, S. E.; Rodal, J. J. A.

1980-01-01

Two computer programs are described for predicting the transient large deflection elastic viscoplastic responses of thin single layer, initially flat unstiffened or integrally stiffened, Kirchhoff-Lov ductile metal panels. The PLATE 1 program pertains to structural responses produced by prescribed externally applied transient loading or prescribed initial velocity distributions. The collision imparted velocity method PLATE 1 program concerns structural responses produced by impact of an idealized nondeformable fragment. Finite elements are used to represent the structure in both programs. Strain hardening and strain rate effects of initially isotropic material are considered.

Disturbed alternative splicing of FIR (PUF60) directed cyclin E overexpression in esophageal cancers.

PubMed

Ogura, Yukiko; Hoshino, Tyuji; Tanaka, Nobuko; Ailiken, Guzhanuer; Kobayashi, Sohei; Kitamura, Kouichi; Rahmutulla, Bahityar; Kano, Masayuki; Murakami, Kentarou; Akutsu, Yasunori; Nomura, Fumio; Itoga, Sakae; Matsubara, Hisahiro; Matsushita, Kazuyuki

2018-05-01

Overexpression of alternative splicing of far upstream element binding protein 1 (FUBP1) interacting repressor (FIR; poly(U) binding splicing factor 60 [PUF60]) and cyclin E were detected in esophageal squamous cell carcinomas (ESCC). Accordingly, the expression of FBW7 was examined by which cyclin E is degraded as a substrate via the proteasome system. Expectedly, FBW7 expression was decreased significantly in ESCC. Conversely, c-myc gene transcriptional repressor FIR (alias PUF60; U2AF-related protein) and its alternative splicing variant form (FIRΔexon2) were overexpressed in ESCC. Further, anticancer drugs (cis-diaminedichloroplatinum/cisplatin [CDDP] or 5-fluorouracil [5-FU]) and knockdown of FIR by small interfering RNA (siRNA) increased cyclin E while knockdown of FIRΔexon2 by siRNA decreased cyclin E expression in ESCC cell lines (TE1, TE2, and T.Tn) or cervical SCC cells (HeLa cells). Especially, knockdown of SAP155 (SF3b1), a splicing factor required for proper alternative splicing of FIR pre-mRNA, decreased cyclin E. Therefore, disturbed alternative splicing of FIR generated FIR/FIRΔexon2 with cyclin E overexpression in esophageal cancers, indicating that SAP155 siRNA potentially rescued FBW7 function by reducing expression of FIR and/or FIRΔexon2. Remarkably, Three-dimensional structure analysis revealed the hypothetical inhibitory mechanism of FBW7 function by FIR/FIRΔexon2, a novel mechanism of cyclin E overexpression by FIR/FIRΔexon2-FBW7 interaction was discussed. Clinically, elevated FIR expression potentially is an indicator of the number of lymph metastases and anti-FIR/FIRΔexon2 antibodies in sera as cancer diagnosis, indicating chemical inhibitors of FIR/FIRΔexon2-FBW7 interaction could be potential candidate drugs for cancer therapy. In conclusion, elevated cyclin E expression was, in part, induced owing to potential FIR/FIRΔexon2-FBW7 interaction in ESCC.

Far infrared promotes wound healing through activation of Notch1 signaling.

PubMed

Hsu, Yung-Ho; Lin, Yuan-Feng; Chen, Cheng-Hsien; Chiu, Yu-Jhe; Chiu, Hui-Wen

2017-11-01

The Notch signaling pathway is critically involved in cell proliferation, differentiation, development, and homeostasis. Far infrared (FIR) has an effect that promotes wound healing. However, the underlying molecular mechanisms are unclear. In the present study, we employed in vivo and HaCaT (a human skin keratinocyte cell line) models to elucidate the role of Notch1 signaling in FIR-promoted wound healing. We found that FIR enhanced keratinocyte migration and proliferation. FIR induced the Notch1 signaling pathway in HaCaT cells and in a microarray dataset from the Gene Expression Omnibus database. We next determined the mRNA levels of NOTCH1 in paired normal and wound skin tissues derived from clinical patients using the microarray dataset and Ingenuity Pathway Analysis software. The result indicated that the Notch1/Twist1 axis plays important roles in wound healing and tissue repair. In addition, inhibiting Notch1 signaling decreased the FIR-enhanced proliferation and migration. In a full-thickness wound model in rats, the wounds healed more rapidly and the scar size was smaller in the FIR group than in the light group. Moreover, FIR could increase Notch1 and Delta1 in skin tissues. The activation of Notch1 signaling may be considered as a possible mechanism for the promoting effect of FIR on wound healing. FIR stimulates keratinocyte migration and proliferation. Notch1 in keratinocytes has an essential role in FIR-induced migration and proliferation. NOTCH1 promotes TWIST1-mediated gene expression to assist wound healing. FIR might promote skin wound healing in a rat model. FIR stimulates keratinocyte migration and proliferation. Notch1 in keratinocytes has an essential role in FIR-induced migration and proliferation. NOTCH1 promotes TWIST1-mediated gene expression to assist wound healing. FIR might promote skin wound healing in a rat model.

Convolution Algebra for Fluid Modes with Finite Energy

DTIC Science & Technology

1992-04-01

signals and systems analysis: the evaluation of the initial condition -or input- to a system given its final condition -or output- and its impulse ...Images Corrupted with Gaussian Blur .............. 30 III.. 5 Deblurring with Hermite-Rodriguez Wavelets 34 5.1 Introduction...66 25. Letter "T", which is diffused for t=12, and corrupted by additive noise at SNR’s = 1

Numerical modeling of the exterior-to-interior transmission of impulsive sound through three-dimensional, thin-walled elastic structures

NASA Astrophysics Data System (ADS)

Remillieux, Marcel C.; Pasareanu, Stephanie M.; Svensson, U. Peter

2013-12-01

Exterior propagation of impulsive sound and its transmission through three-dimensional, thin-walled elastic structures, into enclosed cavities, are investigated numerically in the framework of linear dynamics. A model was developed in the time domain by combining two numerical tools: (i) exterior sound propagation and induced structural loading are computed using the image-source method for the reflected field (specular reflections) combined with an extension of the Biot-Tolstoy-Medwin method for the diffracted field, (ii) the fully coupled vibro-acoustic response of the interior fluid-structure system is computed using a truncated modal-decomposition approach. In the model for exterior sound propagation, it is assumed that all surfaces are acoustically rigid. Since coupling between the structure and the exterior fluid is not enforced, the model is applicable to the case of a light exterior fluid and arbitrary interior fluid(s). The structural modes are computed with the finite-element method using shell elements. Acoustic modes are computed analytically assuming acoustically rigid boundaries and rectangular geometries of the enclosed cavities. This model is verified against finite-element solutions for the cases of rectangular structures containing one and two cavities, respectively.

Digital carrier demodulator employing components working beyond normal limits

NASA Technical Reports Server (NTRS)

Hurd, William J. (Inventor); Sadr, Ramin (Inventor)

1990-01-01

In a digital device, having an input comprised of a digital sample stream at a frequency F, a method is disclosed for employing a component designed to work at a frequency less than F. The method, in general, is comprised of the following steps: dividing the digital sample stream into odd and even digital samples streams each at a frequency of F/2; passing one of the digital sample streams through the component designed to work at a frequency less than F where the component responds only to the odd or even digital samples in one of the digital sample streams; delaying the other digital sample streams for the time it takes the digital sample stream to pass through the component; and adding the one digital sample stream after passing through the component with the other delayed digital sample streams. In the specific example, the component is a finite impulse response filter of the order ((N + 1)/2) and the delaying step comprised passing the other digital sample streams through a shift register for a time (in sampling periods) of ((N + 1)/2) + r, where r is a pipline delay through the finite impulse response filter.

The use of linear programming techniques to design optimal digital filters for pulse shaping and channel equalization

NASA Technical Reports Server (NTRS)

Houts, R. C.; Burlage, D. W.

1972-01-01

A time domain technique is developed to design finite-duration impulse response digital filters using linear programming. Two related applications of this technique in data transmission systems are considered. The first is the design of pulse shaping digital filters to generate or detect signaling waveforms transmitted over bandlimited channels that are assumed to have ideal low pass or bandpass characteristics. The second is the design of digital filters to be used as preset equalizers in cascade with channels that have known impulse response characteristics. Example designs are presented which illustrate that excellent waveforms can be generated with frequency-sampling filters and the ease with which digital transversal filters can be designed for preset equalization.

Silvical characteristics of balsam fir (Abies balsamea)

Treesearch

Arthur C. Hart

1959-01-01

Balsam fir takes its name from the Latin word for balm. Some people know the tree as the Balm-of-Gilead fir. It has also been called the blister fir, because of the bark blisters that yield Canada balsam, a resin that is used for, among other things, mounting microscope slides. The needles of balsam fir have a spicy aroma that Donald Culross Peattie has called "...

Predicting susceptibility of white fir during a drought-associated outbreak of the fir engraver, Scolytus centralis, in California

Treesearch

G.T. Ferrell; W.J. Otrosina; C.J. DeMars

1994-01-01

Phenotypic traits were compared with a vigor (growth efficiency) index for accuracy in predicting susceptibility of white fir, Abies concolor (Gord. & Glend.) Lindl., during a drought-associated outbreak of the fir engraver, Scolytus centralis LeC., in the central Sierra Nevada at Lake Tahoe, California.Predictor variables were estimated for 633 firs in six forest...

Seed maturity in white fir and red fir

Treesearch

William W. Oliver

1974-01-01

White fir and red fir seed collected over a 2-month period in northern California was tested for germination of fresh and stratified seed. Ratio of embryo length to embryo cavity length was found to be the most useful index of seed maturity for white and red fir. Cone specific gravity also was correlated with nearly all measures of seed germination. Data suggest that...

Differential susceptibility of white fir provenances to the fir engraver and its fungal symbiont in northern California

Treesearch

G.T. Ferrell; W.J. Otrosina

1996-01-01

The fir engraver, Scolytus ventralis LeC., attacks white fir, Abies concolor (Gord. and Glend.) Lindl., and other true firs, Abies spp., in western North America. The biology, attack behavior, and ecology of this bark beetle were recently summarized by Berryman and Ferrell (1988). During the summer flight season, the attacking beetles bore into the cambial zone of...

Demonstrating a New Census of Infrared Galaxies with ALMA (DANCING-ALMA). I. FIR Size and Luminosity Relation at z = 0-6 Revealed with 1034 ALMA Sources

NASA Astrophysics Data System (ADS)

Fujimoto, Seiji; Ouchi, Masami; Shibuya, Takatoshi; Nagai, Hiroshi

2017-11-01

We present the large statistics of the galaxy effective radius R e in the rest-frame far-infrared (FIR) wavelength {R}{{e}({FIR})} obtained from 1627 Atacama Large Millimeter/submillimeter Array (ALMA) 1 mm band maps that become public by 2017 July. Our ALMA sample consists of 1034 sources with the star formation rate ˜ 100{--}1000 {M}⊙ {{yr}}-1 and the stellar mass ˜ {10}10{--}{10}11.5 {M}⊙ at z = 0-6. We homogeneously derive {R}{{e}({FIR})} and FIR luminosity L FIR of our ALMA sources via the uv-visibility method with the exponential disk model, carefully evaluating selection and measurement incompletenesses by realistic Monte-Carlo simulations. We find that there is a positive correlation between {R}{{e}({FIR})} and L FIR at the >99% significance level. The best-fit power-law function, {R}{{e}({FIR})}\\propto {L}{FIR}α , provides α =0.28+/- 0.07, and shows that {R}{{e}({FIR})} at a fixed L FIR decreases toward high redshifts. The best-fit α and the redshift evolution of {R}{{e}({FIR})} are similar to those of R e in the rest-frame UV (optical) wavelength {R}{{e}({UV})} ({R}{{e}({Opt}.)}) revealed by Hubble Space Telescope (HST) studies. We identify that our ALMA sources have significant trends of {R}{{e}({FIR})}≲ {R}{{e}({UV})} and {R}{{e}({Opt}.)}, which suggests that the dusty starbursts take place in compact regions. Moreover, {R}{{e}({FIR})} of our ALMA sources is comparable to {R}{{e}({Opt}.)} of quiescent galaxies at z ˜ 1-3 as a function of stellar mass, supporting the evolutionary connection between these two galaxy populations. We also investigate rest-frame UV and optical morphologies of our ALMA sources with deep HST images, and find that ˜30%-40% of our ALMA sources are classified as major mergers. This indicates that dusty starbursts are triggered by not only the major mergers but also the other mechanism(s).

Risk-rating systems for mature red fir and white fir in northern California

Treesearch

George T. Ferrell

1980-01-01

On the basis of crown and bole characteristics, risk-rating systems to predict the probability that a tree will die within 5 years were developed for mature red fir and white fir in northern California. The systems apply to firs at least 10 inches (25.4 cm) in diameter-at-breast-height (d.b.h.), growing in mature stands, with the original overstory at least partially...

Assessing the susceptibility of white fir to the fir engraver, Scolytus ventralis Lec. (Coleoptera: Scolytidae), using fungal inoculation

Treesearch

G.T. Ferrell; W.J. Otrosina; C.J. DeMars

1993-01-01

A method of assessing susceptibility of white fir, Abies concolor (Gord. and Glend.) Lindl., by fungal inoculation was tested during an outbreak of the fir engraver beetle, Scolytus ventralis LeC., at Lake Tahoe, California, in 1987 through 1989.A total of 592 firs growing in six forest stands containing trees infested by the beetle were inoculated with the mutualistic...

Allelochemicals and activities in a replanted Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) tree ecosystem.

PubMed

Kong, C H; Chen, L C; Xu, X H; Wang, P; Wang, S L

2008-12-24

Autotoxicity is a major reason for replant problems in managed tree ecosystems. Studies have related phenolics-based allelochemicals to autotoxicity. We selected a 20-year-old replanted Chinese fir [Cunninghamia lancealata (Lamb.) Hook] tree ecosystem to isolate, identify, determine the biological activity of, and quantify soil phytotoxins. Eight common phenolics (coumarin, vanillin, isovanillin, and p-hydroxybenzoic, vanillic, benzoic, cinnamic, and ferulic acids), friedelin, and a novel cyclic dipeptide (6-hydroxy-1,3-dimethyl-8-nonadecyl-[1,4]-diazocane-2,5-diketone) were obtained by using the bioassay-guided isolation technique from toxic soil of the replanted Chinese fir tree ecosystem. Chemical structures were determined by spectroscopic means, including 2D-NMR (COSY, HMQC, HMBC, and NOESY) experiments. High concentrations of soil phenolics and friedelin were observed in the natural evergreen broadleaf forest (CK) rather than in the Chinese fir tree ecosystem. The phenolics and friedelin were not phytotoxic to Chinese fir trees. However, the cyclic dipeptide inhibited Chinese fir growth at soil concentrations determined in the replanted Chinese fir tree ecosystem. There was a significantly higher soil concentration of cyclic dipeptide in the replanted Chinese fir tree ecosystem than in a fresh Chinese fir tree ecosystem. The results suggest that phenolics and friedelin are not key allelochemicals since they are weakly phytotoxic and are detected in low concentrations in the replanted Chinese fir tree ecosystem, while cyclic dipeptide is a highly active allelochemical with a phytotoxic effect that limits offspring growth in the replanted Chinese fir tree ecosystem. The discovery of cyclic dipeptide, as well as a further understanding of its potential action mechanism in the replanted Chinese fir tree ecosystem, may contribute to solving the replant problems in managed tree ecosystems.

Precommercial thinning in mixed-species conifer plantations affected by armillaria and heterobasidion root diseases in West-Central Oregon and Washington: 30-year results

Treesearch

Gregory M. Filip; Joshua J. Bronson; Kristen L. Chadwick; Jeremy B. Filip; Susan J. Frankel; Donald J. Goheen; Ellen M. Goheen; Sylvia R. Mori; Angel L. Saavedra

2015-01-01

Four 10- to 20-year-old plantations were precommercially thinned to determine the effects on tree growth and mortality caused by armillaria and heterobasidion root diseases. The plantations represented different species compositions with one each of (1) coastal Douglas-fir and noble fir, (2) Douglas-fir and western hemlock, (3) pure Douglas-fir, and (4) Shasta red fir...

Hybridization of a Rocky Mountain fir (Abies concolor) and a Mexican fir (Abies religiosa).

Treesearch

J.B. St. Clair; W.B. Critchfield

1988-01-01

Interspecific crosses of Abies religiosa (HBK.) Schlecht. & Cham. (oyamel) with Abies concolor (Gord. & Glend.) Lindle. ex Hildebr. var. concolor (white fir) and Abies magnifica A. Murr. (California red fir) were undertaken to explore the relationships between these species. The...

Inhibition of the growth of Alexandrium tamarense by algicidal substances in Chinese fir (Cunninghamia lanceolata).

PubMed

Yang, Wei-Dong; Liu, Jie-Sheng; Li, Hong-Ye; Zhang, Xin-Lian; Qi, Yu-Zao

2009-10-01

The wood sawdust from Chinese fir (Cunninghamia lanceolata) exhibited stronger inhibition on the growth of Alexandrium tamarense than those from alder (Alnus cremastogyne), pine (Pinus massoniana), birch (Betula alnoides) and sapele (Entandrophragma cylindricum). The water extract, acetone-water extract and essential oil from fir sawdust were all shown to inhibit the growth of A. tamarense. The inhibition of fir essential oil was the strongest among all the above wood sources while the half effective concentration was only 0.65 mg/L. These results suggested that the fir essential oil may play an important role in the algicidal effect of Chinese fir.

Hybridization of a Rocky Mountain fir (Abies concolor) and a Mexican fir (Abies religiosa)

Treesearch

J. B. St. Clair; W. B. Critchfield

1988-01-01

Interspecific crosses of Abies religiosa (HBK.) Schlecht. & Cham, (oyamel) with Abies concolor (Gord. & Glend.) Lindl. ex Hildebr. var. concolor (white fir) and Abies magnifica A. Murr. (California red fir) were undertaken to explore the relationships between these species. The cross...

User's guide to the Douglas-fir beetle impact model

Treesearch

Michael A. Marsden; Bov B. Eav; Matthew K. Thompson

1993-01-01

Douglas-fir beetle (Dendroctonus pseudotsugae Hopk.) occurs throughout the range of its principal host, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). At epidemic levels, the beetle causes considerable mortality in large-diameter Douglas-fir trees. Wind storms, drought, fire, and other factors have been reported as precedent...

Douglas-Fir Tussock Moth

Treesearch

Boyd E. Wickman; Richard R. Mason; Galen C. Trostle

1981-01-01

The Douglas-fir tussock moth (Orgyia pseudotsugata McDunnough) is an important defoliator of true firs and Douglas-fir in Western North America. Severe tussock moth outbreaks have occurred in British Columbia, Idaho, Washington, Oregon, Nevada, California, Arizona, and New Mexico, but the area subject to attack is more extensive

FPGA-based fused smart sensor for dynamic and vibration parameter extraction in industrial robot links.

PubMed

Rodriguez-Donate, Carlos; Morales-Velazquez, Luis; Osornio-Rios, Roque Alfredo; Herrera-Ruiz, Gilberto; de Jesus Romero-Troncoso, Rene

2010-01-01

Intelligent robotics demands the integration of smart sensors that allow the controller to efficiently measure physical quantities. Industrial manipulator robots require a constant monitoring of several parameters such as motion dynamics, inclination, and vibration. This work presents a novel smart sensor to estimate motion dynamics, inclination, and vibration parameters on industrial manipulator robot links based on two primary sensors: an encoder and a triaxial accelerometer. The proposed smart sensor implements a new methodology based on an oversampling technique, averaging decimation filters, FIR filters, finite differences and linear interpolation to estimate the interest parameters, which are computed online utilizing digital hardware signal processing based on field programmable gate arrays (FPGA).

FPGA-Based Fused Smart Sensor for Dynamic and Vibration Parameter Extraction in Industrial Robot Links

PubMed Central

Rodriguez-Donate, Carlos; Morales-Velazquez, Luis; Osornio-Rios, Roque Alfredo; Herrera-Ruiz, Gilberto; de Jesus Romero-Troncoso, Rene

2010-01-01

Intelligent robotics demands the integration of smart sensors that allow the controller to efficiently measure physical quantities. Industrial manipulator robots require a constant monitoring of several parameters such as motion dynamics, inclination, and vibration. This work presents a novel smart sensor to estimate motion dynamics, inclination, and vibration parameters on industrial manipulator robot links based on two primary sensors: an encoder and a triaxial accelerometer. The proposed smart sensor implements a new methodology based on an oversampling technique, averaging decimation filters, FIR filters, finite differences and linear interpolation to estimate the interest parameters, which are computed online utilizing digital hardware signal processing based on field programmable gate arrays (FPGA). PMID:22319345

Effects of far-infrared radiation on heart rate variability and central manifestations in healthy subjects: a resting-fMRI study.

PubMed

Lin, Yii-Jeng; Kung, Yen-Ying; Kuo, Wen-Jui; Niddam, David M; Cheng, Chou-Ming; Chou, Chih-Che; Yeh, Tzu-Chen; Hsieh, Jen-Chuen; Chiu, Jen-Hwey

2015-01-01

The aim of this study was to investigate the autonomic responses and central manifestations by peripheral FIR stimulation. Ten subjects (mean ± SD age 26.2 ± 3.52 years) received FIR stimulation at left median nerve territory for 40 min. Electrocardiograph was continuously recorded and heart rate variability (HRV) were analyzed. By using a 3 T-MRI scanner, three sessions of resting-state functional magnetic resonance images (fMRI) were acquired, namely, before (baseline-FIR), immediately after (IA-FIR) and 15 min after FIR was turned off (Post-FIR). The fractional amplitude of low-frequency (0.01-0.08 Hz) fluctuation (fALFF) of each session to evaluate the intensity of resting-brain activity in each session was analyzed. Our results showed that FIR stimulation induced significant HRV responses such as an increasing trend of nLF and LF/HF ratio, while FIR increased fALFF in right superior front gyrus, middle frontal gyrus and decreased the resting brain activity at fusiform gyrus, extrastriae cortex, inferior temporal gyrus and middle temporal gyrus, especially 15 min after FIR was turned off. We conclude that the central manifestation and the autonomic responses are prominent during and after FIR stimulation, which provide important mechanistic explanation on human disorder treated by such energy medicine.

Acoustic waves from mechanical impulses due to fluorescence resonant energy (Förster) transfer: Blowing a whistle with light

NASA Astrophysics Data System (ADS)

Zurita-Sánchez, J. R.; Henkel, C.

2012-02-01

We present a momentum transfer mechanism mediated by electromagnetic fields that originates in a system of two nearby molecules: one excited (donor D*) and the other in ground state (acceptor A). An intermolecular force related to fluorescence resonant energy or Förster transfer (FRET) arises in the unstable D*A molecular system, which differs from the equilibrium van der Waals interaction. Due to the its finite lifetime, a mechanical impulse is imparted to the relative motion in the system. We analyze the FRET impulse when the molecules are embedded in free space and find that its magnitude can be much greater than the single recoil photon momentum, getting comparable with the thermal momentum (Maxwell-Boltzmann distribution) at room temperature. In addition, we propose that this FRET impulse can be exploited in the generation of acoustic waves inside a film containing layers of donor and acceptor molecules, when a picosecond laser pulse excites the donors. This acoustic transient is distinguishable from that produced by thermal stress due to laser absorption, and may therefore play a role in photoacoustic spectroscopy. The effect can be seen as exciting a vibrating system like a string or organ pipe with light; it may be used as an opto-mechanical transducer.

Noble fir: a bibliography with abstracts.

Treesearch

Jerry F. Franklin

1962-01-01

This bibliography on noble fir (Abies procera Rehd.) includes both North American and European references. Its purpose is to list articles for those interested in the species; the most important references have been abstracted. An article concerning California red fir and one concerning Shasta red fir are included, as their silvical characteristics...

User's guide to the douglas-fir beetle impact model. Forest Service general technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marsden, M.A.; Eav, B.B.; Thompson, M.K.

1994-09-01

Douglas-fir beetle occurs throughout the range of its principal host, Douglas-fir. At epidemic levels, the beetle causes considerable mortality in large-diameter Douglas-fir trees. Wind storms, drought, fire, and other factors have been reported as precendent conditions for epidemics of Douglas-fir beetle. An impact model has been developed to simulate tree mortality during such epidemics. The model has been linked to the Stand Prognosis Model (Forest Vegetation Simulator). This is a guide for using the model.

[Community stability for spruce-fir forest at different succession stages in Changbai Mountains, Northeast China].

PubMed

Zhang, Meng-tao; Zhang, Qing; Kang, Xin-gang; Yang, Ying-jun; Xu, Guang; Zhang, Li-xin

2015-06-01

Based on the analysis of three forest communities (polar-birch secondary forest, spruce-fir mixed forest, spruce-fir near pristine forest) in Changbai Mountains, a total of 22 factors of 5 indices, including the population regeneration, soil fertility (soil moisture and soli nutrient), woodland productivity and species diversity that reflected community characteristics were used to evaluate the stability of forest community succession at different stages by calculating subordinate function values of a model based on fuzzy mathematics. The results that the indices of population regeneration, soli nutrient, woodland productivity and species diversity were the highest in the spruce-fir mixed forest, and the indices of soil moisture were the highest in the spruce-fir near-pristine forest. The stability of three forest communities was in order of natural spruce-fir mixed forest > spruce-fir near pristine forest > polar-birch secondary forest.

Selective Transient Cooling by Impulse Perturbations in a Simple Toy Model

NASA Astrophysics Data System (ADS)

Fabrizio, Michele

2018-06-01

We show in a simple exactly solvable toy model that a properly designed impulse perturbation can transiently cool down low-energy degrees of freedom at the expense of high-energy ones that heat up. The model consists of two infinite-range quantum Ising models: one, the high-energy sector, with a transverse field much bigger than the other, the low-energy sector. The finite-duration perturbation is a spin exchange that couples the two Ising models with an oscillating coupling strength. We find a cooling of the low-energy sector that is optimized by the oscillation frequency in resonance with the spin exchange excitation. After the perturbation is turned off, the Ising model with a low transverse field can even develop a spontaneous symmetry breaking despite being initially above the critical temperature.

Predicting postfire Douglas-fir beetle attacks and tree mortality in the northern Rocky Mountains

Treesearch

Sharon Hood; Barbara Bentz

2007-01-01

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were monitored for 4 years following three wildfires. Logistic regression analyses were used to develop models predicting the probability of attack by Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins, 1905) and the probability of Douglas-fir mortality within 4 years following...

Losses associated with Douglas-fir and true fir tops killed by western spruce budworm in eastern Washington.

Treesearch

Paul E. Aho

1984-01-01

A sample of 133 Douglas-firs (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and 69 true firs (Abies spp.) with dead tops caused by defoliation by the western spruce budworm (Choristoneura occidentalis Freeman) were felled, dissected, and examined for height loss and incidence and...

Composition of root pressure exudate from conifers.

Treesearch

D.O. Ketchie; W. Lopushinsky

1981-01-01

Root pressure exudates collected from detopped seedlings of Douglas-fir, grand fir, noble fir, Pacific silver fir, ponderosa pine, lodgepole pine, and Engelmann spruce were analyzed for sugars, amino acids, organic acids, nitrogen, potassium, calcium, and magnesium. Sugar concentrations ranged from 0.10 percent to 5 percent, and included glucose, sucrose, fructose, and...

Effects of fir sawyer beetle on spatial structure of Siberian fir stands

Treesearch

Vladimir L. Gavrikov; Valentina P. Vetrova

1991-01-01

Insects not only use plants for food and habitat; they also change plant populations by influencing their structure and dynamics. This influence is evidenced in the alteration of the spatial structure of a stand. The fir sawyer, Monochamus urussovi Fisch. (Coleoptera: Cerambycidae), is the most abundant xylophagous insect injuring siberian fir,...

Timing of aerial surveys for the balsam woolly aphid

Treesearch

W.J. Buckhorn; Paul G. Lauterbach

1957-01-01

An outbreak of the balsam woolly aphid (Chermes piceae Ratz.) is damaging and killing Pacific silver fir, subalpine fir, and grand fir extensively in western Washington and Oregon. It is most serious in southern Washington where an outbreak on Pacific silver fir was discovered in 1954. Since effective methods for controlling this insect under...

Biological Degradation of Chinese Fir with Trametes Versicolor (L.) Lloyd

PubMed Central

Chen, Meiling; Wang, Chuangui; Fei, Benhua; Ma, Xinxin; Zhang, Bo; Zhang, Shuangyan; Huang, Anmin

2017-01-01

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) has been an important afforestation species in northeast China. It has obvious defects of buckling and cracking easily, which are caused by its chemical components. Trametes versicolor (L.) Lloyd, a white-rot fungus, can decompose the cellulose, hemicellulose, and lignin in the wood. White-rot fungus was used to biologically degrade Chinese fir wood. The effects of different degradation time on the Chinese fir wood’s mechanical properties, micromorphology, chemical components, and crystallinity were studied. The results showed that the heartwood of Chinese fir was more durable than the sapwood and the durability class of Chinese fir was III. Trametes versicolor (L.) Lloyd had a greater influence on the mechanical properties (especially with respect to the modulus of elasticity (MOE)) for the sapwood. Trametes versicolor (L.) Lloyd degraded Chinese fir and colonized the lumen of various wood cell types in Chinese fir, penetrated cell walls via pits, caused erosion troughs and bore holes, and removed all cell layers. The ability of white-rot fungus to change the chemical composition mass fraction for Chinese fir was: hemicellulose > lignin > cellulose. The durability of the chemical compositions was: lignin > cellulose > hemicellulose. The crystallinity of the cellulose decreased and the mean size of the ordered (crystalline) domains increased after being treated by white-rot fungus. PMID:28773191

Association of Far-Infrared Radiation Therapy and Ankle-Brachial Index of Patients on Hemodialysis with Peripheral Artery Occlusive Disease

PubMed Central

Chen, Szu-Chia; Lee, Mei-Yueh; Huang, Jiun-Chi; Kuo, I-Ching; Mai, Hsiu-Chin; Kuo, Po-Lin; Chang, Jer-Ming; Hwang, Shang-Jyh; Chen, Hung-Chun

2016-01-01

Background and Aim: The ankle-brachial index (ABI) is recognized to be a good marker for atherosclerosis, and is useful in the diagnosis of peripheral artery occlusive disease (PAOD) which is prevalent among patients on hemodialysis (HD). Methods: This randomized trial aimed to evaluate the effect of far-infrared radiation (FIR) therapy on ABI in HD patients with PAOD. PAOD was defined as patients with ABI < 0.95. One hundred and eight HD patients were enrolled, including 50 in the control group and 58 in the FIR group. A WS TY101 FIR emitter was applied for 40 minutes during each HD session, three times per week for six months. The ABI was measured before and after the FIR therapy. Results: Regardless of FIR therapy, the bilateral ABI decreased (in the FIR group, left: 0.88±0.22 to 0.85±0.24, p = 0.188; right: 0.92±0.20 to 0.90±0.23, p = 0.372; in control group, left: 0.91±0.23 to 0.88±0.21, p = 0144; right: 0.93±0.17 to 0.89±0.21, p = 0.082). Multivariate logistic analysis of the FIR group revealed that high uric acid (odds ratio [OR]: 2.335; 95% confidence interval [CI]: 1.117-4.882; p=0.024) and aspirin use (OR: 16.463; 95% CI: 1.787-151.638; p=0.013) were independently associated with increased bilateral ABI after FIR therapy. Conclusions: This study demonstrates that ABI is not increased after FIR therapy in HD patients with PAOD. However, in the FIR group, patients with higher uric acid level or those who used aspirin have increased bilateral ABI after FIR therapy. PMID:27994503

Silver fir and Douglas fir are more tolerant to extreme droughts than Norway spruce in south-western Germany.

PubMed

Vitali, Valentina; Büntgen, Ulf; Bauhus, Jürgen

2017-12-01

Improving our understanding of the potential of forest adaptation is an urgent task in the light of predicted climate change. Long-term alternatives for susceptible yet economically important tree species such as Norway spruce (Picea abies) are required, if the frequency and intensity of summer droughts will continue to increase. Although Silver fir (Abies alba) and Douglas fir (Pseudotsuga menziesii) have both been described as drought-tolerant species, our understanding of their growth responses to drought extremes is still limited. Here, we use a dendroecological approach to assess the resistance, resilience, and recovery of these important central Europe to conifer species the exceptional droughts in 1976 and 2003. A total of 270 trees per species were sampled in 18 managed mixed-species stands along an altitudinal gradient (400-1200 m a.s.l.) at the western slopes of the southern and central Black Forest in southwest Germany. While radial growth in all species responded similarly to the 1976 drought, Norway spruce was least resistant and resilient to the 2003 summer drought. Silver fir showed the overall highest resistance to drought, similarly to Douglas fir, which exhibited the widest growth rings. Silver fir trees from lower elevations were more drought prone than trees at higher elevations. Douglas fir and Norway spruce, however, revealed lower drought resilience at higher altitudes. Although the 1976 and 2003 drought extremes were quite different, Douglas fir maintained consistently the highest radial growth. Although our study did not examine population-level responses, it clearly indicates that Silver fir and Douglas fir are generally more resistant and resilient to previous drought extremes and are therefore suitable alternatives to Norway spruce; Silver fir more so at higher altitudes. Cultivating these species instead of Norway spruce will contribute to maintaining a high level of productivity across many Central European mountain forests under future climate change. © 2017 John Wiley & Sons Ltd.

MicroRNA-134 Contributes to Glucose-Induced Endothelial Cell Dysfunction and This Effect Can Be Reversed by Far-Infrared Irradiation

PubMed Central

Wang, Yen-Li; Chang, Shih-Ting; Liao, Ko-Hsun; Lo, Hung-Hao; Chiu, Ya-Lin; Hsieh, Tsung-Han; Huang, Tse-Shun; Lin, Chin-Sheng; Cheng, Shu-Meng; Cheng, Cheng-Chung

2016-01-01

Diabetes mellitus (DM) is a metabolic disease that is increasing worldwide. Furthermore, it is associated with the deregulation of vascular-related functions, which can develop into major complications among DM patients. Endothelial colony forming cells (ECFCs) have the potential to bring about medical repairs because of their post-natal angiogenic activities; however, such activities are impaired by high glucose- (HG) and the DM-associated conditions. Far-infrared radiation (FIR) transfers energy as heat that is perceived by the thermoreceptors in human skin. Several studies have revealed that FIR improves vascular endothelial functioning and boost angiogenesis. FIR has been used as anti-inflammatory therapy and as a clinical treatment for peripheral circulation improvement. In addition to vascular repair, there is increasing evidence to show that FIR can be applied to a variety of diseases, including cardiovascular disorders, hypertension and arthritis. Yet mechanism of action of FIR and the biomarkers that indicate FIR effects remain unclear. MicroRNA-134 (miR-134-5p) was identified by small RNA sequencing as being increased in high glucose (HG) treated dfECFCs (HG-dfECFCs). Highly expressed miR-134 was also validated in dmECFCs by RT-qPCR and it is associated with impaired angiogenic activities of ECFCs. The functioning of ECFCs is improved by FIR treatment and this occurs via a reduction in the level of miR-134 and an increase in the NRIP1 transcript, a direct target of miR-134. Using a mouse ischemic hindlimb model, the recovery of impaired blood flow in the presence of HG-dfECFCs was improved by FIR pretreatment and this enhanced functionality was decreased when there was miR-134 overexpression in the FIR pretreated HG-dfECFCs. In conclusion, our results reveal that the deregulation of miR-134 is involved in angiogenic defects found in DM patients. FIR treatment improves the angiogenic activity of HG-dfECFCs and dmECFCs and FIR has potential as a treatment for DM. Detection of miR-134 expression in FIR-treated ECFCs should help us to explore further the effectiveness of FIR therapy. PMID:26799933

MicroRNA-134 Contributes to Glucose-Induced Endothelial Cell Dysfunction and This Effect Can Be Reversed by Far-Infrared Irradiation.

PubMed

Wang, Hsei-Wei; Su, Shu-Han; Wang, Yen-Li; Chang, Shih-Ting; Liao, Ko-Hsun; Lo, Hung-Hao; Chiu, Ya-Lin; Hsieh, Tsung-Han; Huang, Tse-Shun; Lin, Chin-Sheng; Cheng, Shu-Meng; Cheng, Cheng-Chung

2016-01-01

Diabetes mellitus (DM) is a metabolic disease that is increasing worldwide. Furthermore, it is associated with the deregulation of vascular-related functions, which can develop into major complications among DM patients. Endothelial colony forming cells (ECFCs) have the potential to bring about medical repairs because of their post-natal angiogenic activities; however, such activities are impaired by high glucose- (HG) and the DM-associated conditions. Far-infrared radiation (FIR) transfers energy as heat that is perceived by the thermoreceptors in human skin. Several studies have revealed that FIR improves vascular endothelial functioning and boost angiogenesis. FIR has been used as anti-inflammatory therapy and as a clinical treatment for peripheral circulation improvement. In addition to vascular repair, there is increasing evidence to show that FIR can be applied to a variety of diseases, including cardiovascular disorders, hypertension and arthritis. Yet mechanism of action of FIR and the biomarkers that indicate FIR effects remain unclear. MicroRNA-134 (miR-134-5p) was identified by small RNA sequencing as being increased in high glucose (HG) treated dfECFCs (HG-dfECFCs). Highly expressed miR-134 was also validated in dmECFCs by RT-qPCR and it is associated with impaired angiogenic activities of ECFCs. The functioning of ECFCs is improved by FIR treatment and this occurs via a reduction in the level of miR-134 and an increase in the NRIP1 transcript, a direct target of miR-134. Using a mouse ischemic hindlimb model, the recovery of impaired blood flow in the presence of HG-dfECFCs was improved by FIR pretreatment and this enhanced functionality was decreased when there was miR-134 overexpression in the FIR pretreated HG-dfECFCs. In conclusion, our results reveal that the deregulation of miR-134 is involved in angiogenic defects found in DM patients. FIR treatment improves the angiogenic activity of HG-dfECFCs and dmECFCs and FIR has potential as a treatment for DM. Detection of miR-134 expression in FIR-treated ECFCs should help us to explore further the effectiveness of FIR therapy.

Far-infrared radiation acutely increases nitric oxide production by increasing Ca{sup 2+} mobilization and Ca{sup 2+}/calmodulin-dependent protein kinase II-mediated phosphorylation of endothelial nitric oxide synthase at serine 1179

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Jung-Hyun; Lee, Sangmi; Cho, Du-Hyong

Highlights: •Far-infrared (FIR) radiation increases eNOS-Ser{sup 1179} phosphorylation and NO production in BAEC. •CaMKII and PKA mediate FIR-stimulated increases in eNOS-Ser{sup 1179} phosphorylation. •FIR increases intracellular Ca{sup 2+} levels. •Thermo-sensitive TRPV Ca{sup 2+} channels are unlikely to be involved in the FIR-mediated eNOS-Ser{sup 1179} phosphorylation pathway. -- Abstract: Repeated thermal therapy manifested by far-infrared (FIR) radiation improves vascular function in both patients and mouse model with coronary heart disease, but its underlying mechanism is not fully understood. Using FIR as a thermal therapy agent, we investigate the molecular mechanism of its effect on endothelial nitric oxide synthase (eNOS) activity andmore » NO production. FIR increased the phosphorylation of eNOS at serine 1179 (eNOS-Ser{sup 1179}) in a time-dependent manner (up to 40 min of FIR radiation) in bovine aortic endothelial cells (BAEC) without alterations in eNOS expression. This increase was accompanied by increases in NO production and intracellular Ca{sup 2+} levels. Treatment with KN-93, a selective inhibitor of Ca{sup 2+}/calmodulin-dependent protein kinase II (CaMKII) and H-89, a protein kinase A inhibitor, inhibited FIR radiation-stimulated eNOS-Ser{sup 1179} phosphorylation. FIR radiation itself also increased the temperature of culture medium. As transient receptors potential vanilloid (TRPV) ion channels are known to be temperature-sensitive calcium channels, we explore whether TRPV channels mediate these observed effects. Reverse transcription-PCR assay revealed two TRPV isoforms in BAEC, TRPV2 and TRPV4. Although ruthenium red, a pan-TRPV inhibitor, completely reversed the observed effect of FIR radiation, a partial attenuation (∼20%) was found in cells treated with Tranilast, TRPV2 inhibitor. However, ectopic expression of siRNA of TRPV2 showed no significant alteration in FIR radiation-stimulated eNOS-Ser{sup 1179} phosphorylation. This study suggests that FIR radiation increases NO production via increasing CaMKII-mediated eNOS-Ser{sup 1179} phosphorylation but TRPV channels may not be involved in this pathway. Our results may provide the molecular mechanism by which FIR radiation improves endothelial function.« less

Trapping Douglas-fir beetle (Dendroctonus pseudotsugae) with pheromone baited multiple-funnel traps does not reduce Douglas-fir (Pseudotsuga menziesii) mortality

Treesearch

R.A. Progar; N. Sturdevant; M.J. Rinella

2010-01-01

Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) (DFB) causes considerable mortality to Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in western North American forests. We evaluated the use of semiochemical-baited multiple-funnel traps for the protection of small, high-value stands of trees, such as those occurring...

Size of Douglas-fir trees in relation to distance from a mixed red alder - Douglas-fir stand

Treesearch

R.E. Miller; D.L. Reukema; T.A. Max

1993-01-01

Variation in diameter, height, and stem volume of 57-year-old Douglas-fir(Pseudotsuga menziesii var. menziesii (Mirb.) Franco) was related to distance of these trees from a 27 m wide strip in the same Douglas-fir plantation that had been interplanted with red alder (Alnus rubra Bong.). Within the...

HOW to Identify and Manage Needlecast Diseases on Balsam Fir

Treesearch

Mike Albers; Jana Albers; Jane Cummings Carlson; Linda Haugen; Nancy Wenner

1996-01-01

Needlecast diseases are common in balsam fir stands and Christmas tree plantations in the northeastern and north central United States and in southern Ontario, Quebec, and New Brunswick. Three different needlecast fungi, Lirula nervata, Lirula mirabilis and Isthmiella faullii, cause similar disease symptoms on balsam fir. These diseases may affect other firs planted in...

Ten-year risk-rating systems for California red fir and white fir: development and use

Treesearch

George T. Ferrell

1989-01-01

Logistic regression equations predicting the probability that a tree will die from natural causes--insects, diseases, intertree competition--within 10 years have been developed for California red fir (Abies magnifica) and white fir (A. concolor). The equations, like those with a 5-year prediction period already developed for these...

Diagnosis of Annosus Root Disease in Mixed Conifer Forests in the Northwestern United States

Treesearch

Craig L. Schmitt

1989-01-01

Recognizing annosus root disease affecting conifers in northwestern United States forests is discussed. Field diagnosis can bemade by observing characteristic stand patterns, wood stain and decay, ectotrophic mycelium, and sporophores. Most seriously affected trees include hemlocks, grand fir, white fir and Pacific silver fir. Ponderosa pine and other true firs may...

Decay of subalpine fir in Colorado

Treesearch

Thomas E. Hinds; Frank G. Hawksworth; Ross W. Davidson

1960-01-01

Spruce-fir is one of the major forest types in the central Rocky Mountains. Engelmann spruce, Picea engelmanni Parry, is usually the predominant species with subalpine fir, Abies lasiocarpa (Hook. ) Nutt., making up one-fourth or less of the total volume. Lodgepole pine, Pinus contorta Dougl. ex Loud., is frequently present at the lower elevations of the spruce-fir...

Stability of nuclear DNA content among divergent and isolated populations of Fraser fir

Treesearch

L.D. Auckland; J.S. Johnston; H.J. Price; F.E. Bridgwater

2001-01-01

Fraser fir (Abies fraseri (Pursh) Poir.) is an endemic species consisting of six major disjunct populations in the Appalachian Mountains, U.S.A. Nuclear DNA content was measured with laser flow cytometry to determine if genome size differences could be detected among the disjunct populations of Fraser fir and its close relatives, balsam fir

Altitudinal gradients of bryophyte diversity and community assemblage in southern Appalachian spruce-fir forests

Treesearch

Sarah E. Stehn; Christopher R. Webster; Janice M. Glime; Michael A. Jenkins

2010-01-01

Ground-layer plant communities in spruce-fir forests of the southern Appalachians have likely undergone significant change since the widespread death of canopy Fraser fir (Abies fraseri) caused by the exotic balsam woolly adelgid (Adelges piceae). Bryophytes comprise an important part of the ground-layer flora in the spruce-fir...

A SYNCHRONIZED FIR/VUV LIGHT SOURCE AT JEFFERSON LAB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stephen Benson, David Douglas, George Neil, Michelle D. Shinn, Gwyn Williams

We describe a dual free-electron laser (FEL) configuration on the UV Demo FEL at Jefferson Lab that allows simultaneous lasing at FIR/THz and UV wavelengths. The FIR/THz source would be an FEL oscillator with a short wiggler providing nearly diffraction-limited pulses with pulse energy exceeding 50 microJoules. The FIR source would use the exhaust beam from a UVFEL. The coherent harmonics in the VUV from the UVFEL are out-coupled through a hole. The FIR source uses a shorter resonator with either hole or edge coupling to provide very high power FIR pulses. Simulations indicate excel-lent spectral brightness in the FIRmore » region with over 100 W/cm-1 output.« less

Explicit Finite Element Method for Transparency Impact Analysis

DTIC Science & Technology

1991-06-01

investigators have employed a similar concept for fiber-reinforced composite laminates (Chow 1971, 1975; Noor 1975, 1989; Chatterjee, 1979). Consider...Intense Impulsive Loads, It. J. Nuon. Meth. Engng. 14, 1865- 1871. Jones, R. M. (1975), Mechanics of Composite Materials, Scripta Book Co., Washington, D...Structural Dynamics, J. Eng. Mech. Div. 85, 67-94. Noor, A. K. (1975), Stability of Multilayered Composite Plates, Fibre Sci. Tech. 8, 81-89. Noor, A. K

Simulating Underbelly Blast Events using Abaqus/Explicit - CEL

DTIC Science & Technology

2013-01-15

describe the material. As a result, a Langragian treatment of the structure is preferred. Therefore, a finite element solver with the capability of...algorithm is a two part process in which all material is deformed with a Lagrange treatment in a given time increment. This is followed by a remapping...accurately describe the material response of geological materials subjected to high impulse loading (i.e. shock events). The hydrostatic behavior of

Far-infrared protects vascular endothelial cells from advanced glycation end products-induced injury via PLZF-mediated autophagy in diabetic mice

PubMed Central

Chen, Cheng-Hsien; Chen, Tso-Hsiao; Wu, Mei-Yi; Chou, Tz-Chong; Chen, Jia-Rung; Wei, Meng-Jun; Lee, San-Liang; Hong, Li-Yu; Zheng, Cai-Mei; Chiu, I-Jen; Lin, Yuh-Feng; Hsu, Ching-Min; Hsu, Yung-Ho

2017-01-01

The accumulation of advanced glycation end products (AGEs) in diabetic patients induces vascular endothelial injury. Promyelocytic leukemia zinc finger protein (PLZF) is a transcription factor that can be activated by low-temperature far-infrared (FIR) irradiation to exert beneficial effects on the vascular endothelium. In the present study, we investigated the influence of FIR-induced PLZF activation on AGE-induced endothelial injury both in vitro and in vivo. FIR irradiation inhibited AGE-induced apoptosis in human umbilical vein endothelial cells (HUVECs). PLZF activation increased the expression of phosphatidylinositol-3 kinases (PI3K), which are important kinases in the autophagic signaling pathway. FIR-induced PLZF activation led to autophagy in HUVEC, which was mediated through the upregulation of PI3K. Immunofluorescence staining showed that AGEs were engulfed by HUVECs and localized to lysosomes. FIR-induced autophagy promoted AGEs degradation in HUVECs. In nicotinamide/streptozotocin-induced diabetic mice, FIR therapy reduced serum AGEs and AGEs deposition at the vascular endothelium. FIR therapy also reduced diabetes-induced inflammatory markers in the vascular endothelium and improved vascular endothelial function. These protective effects of FIR therapy were not found in PLZF-knockout mice. Our data suggest that FIR-induced PLZF activation in vascular endothelial cells protects the vascular endothelium in diabetic mice from AGE-induced injury. PMID:28071754

Natural regeneration 10 years after a Douglas-fir tussock moth outbreak in northeastern Oregon.

Treesearch

B.E. Wickman; K.W. Seidel; G. Lynn Star

1986-01-01

A survey of natural regeneration 10 years after severe grand fir mortality caused by an outbreak of Douglas-fir tussock moth was conducted in the Wenaha-Tucannon Wilderness in the Blue Mountains of northeastern Oregon. Seedling stocking was only moderate, but seedling density was adequate where present. Grand fir is dominating both preoutbreak and postoutbreak...

Douglas-fir growth and yield: research 1909-1960.

Treesearch

R.O. Curtis; D.D. Marshall

2004-01-01

Systematic research on growth and yield of Douglas-fir began in 1909. This line of early research evolved over time and culminated in publication of USDA Bulletin 201, The Yield of Douglas-fir in the Pacific Northwest. B201 had an enormous influence on development of Douglas-fir forestry and was arguably the most influential single research publication ever produced in...

Symptoms associated with inoculation of stems on living Douglas-fir and Grand Fir Trees with Phytophthora ramorum

Treesearch

Gary Chastagner; Kathy Riley; Katie Coats; Marianne Elliott; Annie DeBauw; Norm Dart

2010-01-01

To obtain a better understanding of the potential risk of infection and colonization of living Douglas-fir (Pseudotsuga menziesii) and grand fir (Abies grandis) stems, the stems on over 150 trees of each species were inoculated at a Christmas tree farm near Los Gatos, California. This study had the following objectives: 1)...

Decay in white fir top-killed by Douglas-fir tussock moth.

Treesearch

Boyd E. Wickman; Robert F. Scharpf

1972-01-01

Stands heavily defoliated in 1936-37 by the Douglas-fir tussock moth, Hemerocampa pseudotsugata McD., at Mammoth Lakes, California, were studied to determine the incidence and extent of decay in top-damaged trees. This was done by dissecting the tops of trees felled during logging. Comparisons were made with white fir in a nearby logged area that was...

Growth of White fir after Douglas-fir tussock moth outbreaks: long-term records in the Sierra Nevada.

Treesearch

Boyd E. Wickman

1986-01-01

Radial growth of white fir trees, Abies concolor (Gord. and Glend.) Lindl. ex Hildebr., defoliated almost 30 years ago by Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), in the central Sierra Nevada was compared with 22 years of growth prior to the outbreak. There was little difference in growth between the two...

Little response of true fir saplings to understory shrub removal

Treesearch

William W. Oliver; Fabian C.C. Uzoh

2002-01-01

The ability of white fir and California red fir to become established, persist, and eventually dominate montane shrub fields is well known. When the firs have eventually dominated do the understory shrubs continue to inhibit growth? In a small study in the southern Cascade Range of northeastern California, we tested the growth response of a thinned stand of saplings to...

Environmental characteristics of the Grand Fir Mosaic and adjacent habitat types

Treesearch

Dennis E. Ferguson; John C. Byrne

2000-01-01

Grand Fir Mosaic habitats differ from adjacent forest habitats in their slow rate of secondary succession to woody vegetation. Remote monitoring stations were used to sample the environment at a Grand Fir Mosaic site and three adjacent habitat types. The Grand Fir Mosaic site has shorter growing seasons, cooler temperatures, and more soil moisture than the other sites...

Mortality patterns following spruce budworm infestation in unprotected spruce-fir forests in Maine

Treesearch

Dale S. Solomon; Lianjun Zhang; Thomas B. Brann; David S. Larrick

2003-01-01

Cumulative and annual mortality of red spruce (Picea rubens Sarg.) and balsam fir [Abies balsamea (L) Mill.] were examined over a 10 yr period to follow the mortality patterns in unprotected spruce-fir forests in northern Maine. Different mortality patterns were determined based on stand composition classes and merchantability classes. In general, balsam fir was more...

Early development of matched planted and naturally regenerated Douglas-fir stands after slash burning in the Cascade Range.

Treesearch

R.E. Miller; R.E. Bigley; S. Webster

1993-01-01

We compared matched planted and naturally regenerated plots in 35- to 38- year-old Douglas-fir (Pseudotsuga menziesii var. menziesii) stands at seven locations in western Washington and Oregon. Total number of live stems is similar, but stands planted to Douglas fir average 26 more live stemslac of Douglas-fir and 39 fewer...

Tree Biomass Estimation of Chinese fir (Cunninghamia lanceolata) Based on Bayesian Method

PubMed Central

Zhang, Jianguo

2013-01-01

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) is the most important conifer species for timber production with huge distribution area in southern China. Accurate estimation of biomass is required for accounting and monitoring Chinese forest carbon stocking. In the study, allometric equation was used to analyze tree biomass of Chinese fir. The common methods for estimating allometric model have taken the classical approach based on the frequency interpretation of probability. However, many different biotic and abiotic factors introduce variability in Chinese fir biomass model, suggesting that parameters of biomass model are better represented by probability distributions rather than fixed values as classical method. To deal with the problem, Bayesian method was used for estimating Chinese fir biomass model. In the Bayesian framework, two priors were introduced: non-informative priors and informative priors. For informative priors, 32 biomass equations of Chinese fir were collected from published literature in the paper. The parameter distributions from published literature were regarded as prior distributions in Bayesian model for estimating Chinese fir biomass. Therefore, the Bayesian method with informative priors was better than non-informative priors and classical method, which provides a reasonable method for estimating Chinese fir biomass. PMID:24278198

Tree biomass estimation of Chinese fir (Cunninghamia lanceolata) based on Bayesian method.

PubMed

Zhang, Xiongqing; Duan, Aiguo; Zhang, Jianguo

2013-01-01

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) is the most important conifer species for timber production with huge distribution area in southern China. Accurate estimation of biomass is required for accounting and monitoring Chinese forest carbon stocking. In the study, allometric equation W = a(D2H)b was used to analyze tree biomass of Chinese fir. The common methods for estimating allometric model have taken the classical approach based on the frequency interpretation of probability. However, many different biotic and abiotic factors introduce variability in Chinese fir biomass model, suggesting that parameters of biomass model are better represented by probability distributions rather than fixed values as classical method. To deal with the problem, Bayesian method was used for estimating Chinese fir biomass model. In the Bayesian framework, two priors were introduced: non-informative priors and informative priors. For informative priors, 32 biomass equations of Chinese fir were collected from published literature in the paper. The parameter distributions from published literature were regarded as prior distributions in Bayesian model for estimating Chinese fir biomass. Therefore, the Bayesian method with informative priors was better than non-informative priors and classical method, which provides a reasonable method for estimating Chinese fir biomass.

Ecophysiology and growth of advance red spruce and balsam fir regeneration after partial cutting in yellow birch-conifer stands.

PubMed

Dumais, Daniel; Prévost, Marcel

2008-08-01

We investigated ecophysiological and growth responses of short (0.4 to 1.3 m in height) advance regeneration of red spruce (Picea rubens Sarg.) and balsam fir (Abies balsamea L.) six years after removal of 0, 40, 50, 60 and 100% of the overstory basal area (BA) in two yellow birch-conifer stands. Partial cuts significantly increased stomatal conductance of red spruce only. Light-saturated photosynthesis (leaf-area basis) of both species increased with BA removal, but unlike red spruce, specific leaf area (SLA) of balsam fir decreased with increased cutting intensity. Partial cuts appreciably increased the concentration of N and Ca in red spruce and balsam fir foliage, respectively, and resulted in decreased foliar concentrations of K in red spruce and Mg in balsam fir. The height and lateral growth of both species increased with BA removal, although partial cuts were more beneficial to balsam fir. The data suggest that short advance regeneration of red spruce and balsam fir can coexist under partial overstory conditions, but balsam fir has physiological characteristics and a capacity for morphological adjustment (SLA) that places it at an advantage when in competition with red spruce.

Dual-Emission SG7@MOF Sensor via SC-SC Transformation: Enhancing the Formation of Excimer Emission and the Range and Sensitivity of Detection.

PubMed

Fu, Hong-Ru; Wu, Xiao-Xia; Ma, Lu-Fang; Wang, Fei; Zhang, Jian

2018-05-30

In this study, a water stable metal-organic framework FIR-53 is applied as a single-crystal container for anion exchange. The exceptional chemical stability and low crystallographic symmetry of FIR-53 makes it possible to determine anionic guests. Through ion exchange and single-crystal to single-crystal (SC-SC) transformation, 8-hydroxypyrene-1,3,6-trisulfonate (SG7, solvent green 7, ion form as SG7 3- ) is introduced into the pores of FIR-53 to obtain SG7@FIR-53. Because of the spatial confinement and partition effect, SG7@FIR-53 shows the bright exciter emission of SG7 ions. Interestingly, the composite SG7@FIR-53 exhibits a sensitive fluorescence quenching response against Cr 2 O 7 2- and MnO 4 - in aqueous solution. Especially, the detection limit toward MnO 4 - is as low as 0.12 ppb, which is the smallest value to date. Moreover, the prepared SG7@FIR-53 film also displays a broad response to nitro explosives in vapor/aqueous phase. Compared with the results of FIR-53, the range and sensitivity were greatly improved.

WATER AND METHANOL MASER ACTIVITIES IN THE NGC 2024 FIR 6 REGION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Minho; Kang, Miju; Byun, Do-Young

The NGC 2024 FIR 6 region was observed in the water maser line at 22 GHz and the methanol class I maser lines at 44, 95, and 133 GHz. The water maser spectra displayed several velocity components and month-scale time variabilities. Most of the velocity components may be associated with FIR 6n, while one component was associated with FIR 4. A typical lifetime of the water maser velocity components is about eight months. The components showed velocity fluctuations with a typical drift rate of about 0.01 km s{sup -1} day{sup -1}. The methanol class I masers were detected toward FIRmore » 6. The methanol emission is confined within a narrow range around the systemic velocity of the FIR 6 cloud core. The methanol masers suggest the existence of shocks driven by either the expanding H II region of FIR 6c or the outflow of FIR 6n.« less

Adenovirus-mediated FIR demonstrated TP53-independent cell-killing effect and enhanced antitumor activity of carbon-ion beams.

PubMed

Kano, M; Matsushita, K; Rahmutulla, B; Yamada, S; Shimada, H; Kubo, S; Hiwasa, T; Matsubara, H; Nomura, F

2016-01-01

Combination therapy of carbon-ion beam with the far upstream element-binding protein (FBP)-interacting repressor, FIR, which interferes with DNA damage repair proteins, was proposed as an approach for esophageal cancer treatment with low side effects regardless of TP53 status. In vivo therapeutic antitumor efficacy of replication-defective adenovirus (E1 and E3 deleted adenovirus serotype 5) encoding human FIR cDNA (Ad-FIR) was demonstrated in the tumor xenograft model of human esophageal squamous cancer cells, TE-2. Bleomycin (BLM) is an anticancer agent that introduces DNA breaks. The authors reported that Ad-FIR involved in the BLM-induced DNA damage repair response and thus applicable for other DNA damaging agents. To examine the effect of Ad-FIR on DNA damage repair, BLM, X-ray and carbon-ion irradiation were used as DNA damaging agents. The biological effects of high linear energy transfer (LET) radiotherapy used with carbon-ion irradiation are more expansive than low-LET conventional radiotherapy, such as X-rays or γ rays. High LET radiotherapy is suitable for the local control of tumors because of its high relative biological effectiveness. Ad-FIR enhanced BLM-induced DNA damage indicated by γH2AX in vitro. BLM treatment increased endogenous nuclear FIR expression in TE-2 cells, and P27Kip1 expression was suppressed by TP53 siRNA and BLM treatment. Further, Ad-FIRΔexon2, a dominant-negative form of FIR that lacks exon2 transcriptional repression domain, decreased Ku86 expression. The combination of Ad-FIR and BLM in TP53 siRNA increased DNA damage. Additionally, Ad-FIR showed synergistic cell toxicity with X-ray in vitro and significantly increased the antitumor efficacy of carbon-ion irradiation in the xenograft mouse model of TE-2 cells (P=0.03, Mann-Whitney's U-test) and was synergistic with the sensitization enhancement ratio (SER) value of 1.15. Therefore, Ad-FIR increased the cell-killing activity of the carbon-ion beam that avoids late-phase severe adverse effects independently of the TP53 status in vitro. Our findings indicated the feasibility of the combination of Ad-FIR with DNA damaging agents for future esophageal cancer treatment.

A key to arboreal spiders of Douglas-fir and true fir forests of the Pacific Northwest.

Treesearch

A.R. Moldenke; B.L. Fichter; W.P. Stephen; C.E. Griswold

1987-01-01

This illustrated key for identifying spiders inhabiting true fir and Douglas-fir is based on extensive collections from throughout the three North American Pacific Coast States. Details of the age classes present at budburst and the season in which to expect adults are presented for all species. This paper is written for people unfamiliar as well as familiar with...

Stand and tree characteristics influencing density of fir engraver beetle attack scars in white fir

Treesearch

George T. Ferrell

1973-01-01

Density of embedded scars resulting from old fir engraver (Scolytus ventralis Lec.) attacks was assessed in 3,430 bole cross sections cut from 603 white firs growing in both cutover and in virgin old-growth stands in northern California. Mean scar density was directly related to percentage of mature stand removed by logging and was higher in...

Mortality of spruce and fir in Maine in 1976-78 due to the spruce budworm outbreak

Treesearch

Donald W. Seegrist; Stanford L. Arner

1982-01-01

The spruce budworm population in Maine's spruce-fir forests has been at epidemic levels since the early 1970's. Spruce-fir mortality in 1976-78 is compared with predictions of what mortality would have been had the natural mortality rates remained at the levels experienced before the budworm outbreak. It appears that mortality of spruce and fir has increased...

Impact of the first recorded outbreak of the Douglas-fir tussock moth, Orgyia pseudotsugata, in southern California and the extent of its distribution in the Pacific Southwest region

Treesearch

Tom W. Coleman; Michael I. Jones; Beatrice Courtial; Andrew D. Graves; Meghan Woods; Alain Roques; Steven J. Seybold

2014-01-01

The Douglas-fir tussock moth (DFTM), Orgyia pseudotsugata McDunnough (Lepidoptera:Erebidae: Lymantriinae), is a native western North American defoliator of true fir, Abies spp. Mill., and Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco. We investigated the population genetics and impact associated with the first recorded...

Estimating extent of mortality associated with the Douglas-fir beetle in the Central and Northern Rockies

Treesearch

Jose F. Negron; Willis C. Schaupp; Kenneth E. Gibson; John Anhold; Dawn Hansen; Ralph Thier; Phil Mocettini

1999-01-01

Data collected from Douglas-fir stands infected by the Douglas-fir beetle in Wyoming, Montana, Idaho, and Utah, were used to develop models to estimate amount of mortality in terms of basal area killed. Models were built using stepwise linear regression and regression tree approaches. Linear regression models using initial Douglas-fir basal area were built for all...

Impulse propagation over a complex site: a comparison of experimental results and numerical predictions.

PubMed

Dragna, Didier; Blanc-Benon, Philippe; Poisson, Franck

2014-03-01

Results from outdoor acoustic measurements performed in a railway site near Reims in France in May 2010 are compared to those obtained from a finite-difference time-domain solver of the linearized Euler equations. During the experiments, the ground profile and the different ground surface impedances were determined. Meteorological measurements were also performed to deduce mean vertical profiles of wind and temperature. An alarm pistol was used as a source of impulse signals and three microphones were located along a propagation path. The various measured parameters are introduced as input data into the numerical solver. In the frequency domain, the numerical results are in good accordance with the measurements up to a frequency of 2 kHz. In the time domain, except a time shift, the predicted waveforms match the measured waveforms with a close agreement.

Determination of the critical bending speeds of a multy-rotor shaft from the vibration signal analysis

NASA Astrophysics Data System (ADS)

Crâştiu, I.; Nyaguly, E.; Deac, S.; Gozman-Pop, C.; Bârgău, A.; Bereteu, L.

2018-01-01

The purpose of this paper is the development and validation of an impulse excitation technique to determine flexural critical speeds of a single rotor shaft and multy-rotor shaft. The experimental measurement of the vibroacoustic response is carried out by using a condenser microphone as a transducer. By the means of Modal Analysis using Finite Element Method (FEM), the natural frequencies and shape modes of one rotor and three rotor specimens are determined. The vibration responses of the specimens, in simple supported conditions, are carried out using algorithms based on Fast Fourier Transform (FFT). To validate the results of the modal parameters estimated using Finite Element Analysis (FEA) these are compared with experimental ones.

Recent Advances in Laboratory Infrared Spectroscopy of Polycyclic Aromatic Hydrocarbons: PAHs in the Far Infrared

NASA Technical Reports Server (NTRS)

Mattioda, Andrew L.; Ricca, Alessandra; Tucker, Jonathan; Boersma, Christiaan; Bauschlicher, Charles, Jr.; Allamandola, Louis J.

2010-01-01

Over 25 years of observations and laboratory work have shown that the mid-IR spectra of a majority of astronomical sources are dominated by emission features near 3.3, 6.2, 7.7, and 11.2 microns, which originate in free polycyclic aromatic hydrocarbon (PAH) molecules. PAHs dominate the mid-IR emission from many galactic and extragalactic objects. As such, this material tracks a wide variety of astronomical processes, making this spectrum a powerful probe of the cosmos Apart from bands in the mid-IR, PAHs have bands spanning the Far-IR (FIR) and emission from these FIR features should be present in astronomical sources showing the Mid-IR PAH bands. However, with one exception, the FIR spectral characteristics are known only for a few neutral small PAHs trapped in salt pellets or oils at room temperature, data which is not relevant to astrophysics. Furthermore, since most emitting PAHs responsible for the mid-IR astronomical features are ionized, the absence of any experimental or theoretical PAH ion FIR spectra will make it impossible to correctly interpret the FIR data from these objects. In view of the upcoming Herschel space telescope mission and SOFIA's FIR airborne instrumentation, which will pioneer the FIR region, it is now urgent to obtain PAH FIR spectra. This talk will present an overview recent advances in the laboratory spectroscopy of PAHs, Highlighting the FIR spectroscopy along with some quantum calculations.

Fifteen-year results from a Grand fir-Shasta red fir spacing study.

Treesearch

K.W. Seidel

1987-01-01

A 43-year-old, even-aged stand of advance reproduction of grand fir and Shasta red fir in central Oregon responded to release and thinning with diameter and height growth two to three times the prerelease rate. The response began the first growing season after the overstory was killed with 2,4-D. Diameter growth during the second and third 5-year periods after release...

Tree growth in thinned and unthinned White fir stands 20 years after a Douglas-fir tussock moth outbreak.

Treesearch

Boyd E. Wickman

1988-01-01

Twenty-year postoutbreak growth was compared in thinned and unthinned, severely defoliated stands. Basal area of unthinned white fir has declined 37 percent and pine basal area has increased 32 percent since 1964. The stand thinned in 1960 has the lowest basal area in the study area, but the greatest tree growth before and after the outbreak. All defoliated fir are...

Evolutionary history and population genetics of fraser fir and intermediate fir, southern Appalachian endemic conifers imperiled by an exotic pest and climate change

Treesearch

Kevin M. Potter; John Frampton; Sedley Josserand; C. Dana. Nelson

2010-01-01

Two Abies (true fir) taxa are endemic to high elevations of the Appalachian Mountains, where both are restricted to small populations and are imperiled by the same exotic insect. Fraser fir (Abies fraseri) exists in a handful of island-like populations on mountain ridges in the southern Appalachians of North Carolina, Tennessee and...

A preliminary study of the deterioration of alder and Douglas-fir chips in outdoor piles.

Treesearch

Ernest. Wright

1954-01-01

In the fall of 1952, E. E. Matson of the Pacific Northwest Forest and Range Experiment Station learned that the Fir-Tex Insulating Board Company bf St. Helens, Oregon was considering mixing alder with Douglas-fir chips for outside storage. Since alder heartwood i s more susceptible to decay than that of Douglas-fir, the question arose whether mixing the two might...

The Far Infrared Earth

NASA Technical Reports Server (NTRS)

Harries, John; Carli, Bruno; Rizzi, Rolando; Serio, Carmine; Mlynczak, Martin G.; Palchetti, Luca; Maestri, T.; Brindley, H.; Masiello, Guido

2007-01-01

The paper presents a review of the far infrared (FIR) properties of the Earth's atmosphere, and the role of these properties in climate. These properties have been relatively poorly understood, and it is one of the purposes of this review to demonstrate that, in recent years, we have made great strides in improving this understanding. Seen from space, the Earth is a cool object, with an effective emitting temperature of about 255 K. This contrasts with a global mean surface temperature of 288 K, and is due primarily to strong absorption of outgoing longwave energy by water vapour, carbon dioxide and clouds (especially ice). A large fraction of this absorption occurs in the FIR, and so the Earth is effectively a FIR planet. The FIR is important in a number of key climate processes, for example the water vapour and cloud feedbacks (especially ice clouds). The FIR is also a spectral region which can be used to remotely sense and retrieve atmospheric composition in the presence of ice clouds. Recent developments in instrumentation have allowed progress in each of these areas, which are described, and proposals for a spaceborne FIR instrument are being formulated. It is timely to review the FIR properties of the clear and cloudy atmosphere, the role of FIR processes in climate, and its use in observing our planet from space.

Far-infrared suppresses skin photoaging in ultraviolet B-exposed fibroblasts and hairless mice.

PubMed

Chiu, Hui-Wen; Chen, Cheng-Hsien; Chen, Yi-Jie; Hsu, Yung-Ho

2017-01-01

Ultraviolet (UV) induces skin photoaging, which is characterized by thickening, wrinkling, pigmentation, and dryness. Collagen, which is one of the main building blocks of human skin, is regulated by collagen synthesis and collagen breakdown. Autophagy was found to block the epidermal hyperproliferative response to UVB and may play a crucial role in preventing skin photoaging. In the present study, we investigated whether far-infrared (FIR) therapy can inhibit skin photoaging via UVB irradiation in NIH 3T3 mouse embryonic fibroblasts and SKH-1 hairless mice. We found that FIR treatment significantly increased procollagen type I through the induction of the TGF-β/Smad axis. Furthermore, UVB significantly enhanced the expression of matrix metalloproteinase-1 (MMP-1) and MMP-9. FIR inhibited UVB-induced MMP-1 and MMP-9. Treatment with FIR reversed UVB-decreased type I collagen. In addition, FIR induced autophagy by inhibiting the Akt/mTOR signaling pathway. In UVB-induced skin photoaging in a hairless mouse model, FIR treatment resulted in decreased skin thickness in UVB irradiated mice and inhibited the degradation of collagen fibers. Moreover, FIR can increase procollagen type I via the inhibition of MMP-9 and induction of TGF-β in skin tissues. Therefore, our study provides evidence for the beneficial effects of FIR exposure in a model of skin photoaging.

The FCF Fluids Integrated Rack: Microgravity Fluid Physics Experimentation on Board the ISS

NASA Technical Reports Server (NTRS)

Gati, Frank G.; Hill, Myron E.; SaintOnge, Tom (Technical Monitor)

2001-01-01

The Fluids Integrated Rack (FIR) is a modular, multi-user scientific research facility that will fly in the U.S. laboratory module, Destiny, of the International Space Station (ISS). The FIR will be one of the racks that will constitute the Fluids and Combustion Facility (FCF). The ISS will provide the FCF and therefore the FIR with the necessary resources, such as power and cooling, so that the FIR can carry out its primary mission of accommodating fluid physics science experiments. This paper discusses the mission, design, and the capabilities of the FIR in carrying out research on the ISS.

The heating of dust in starburst galaxies: The contribution of the nonionizing radiation

NASA Technical Reports Server (NTRS)

Calzetti, D.; Bohlin, R. C.; Kinney, Anne L.; Storchi-Bergmann, T.; Heckman, Timothy M.

1995-01-01

The IUE UV and optical spectra and the far-infrared (FIR) IRAS flux densities of a sample of starburst and blue compact galaxies are used to investigate the relationship between dust obscuration and dust emission. The amount of dust obscuration at UV wavelengths correlates with the FIR-to-blue ratio; and an analysis of the correlation indicates that not only the ionizing but also the nonionizing radiation contribute to the FIR emission. The amount of UV and optical energy lost to dust obscuration accounts for most of the cool dust FIUR emission and for about 70% of the warm dust FIR emission. The remaining 30% of the warm dust FIR flux is probably due to dust emission from regions of star formation which are embedded in opaque giant molecular clouds and do not contribute to the integrated UV and optical spectrum. The use of the FIR emission as an indicator of high-mass star formation rate in star-forming galaxies can be problematic, since the contribution to the FIR flux from cool dust emission heated by relatively old stars is nonnegligible.

A decentralized linear quadratic control design method for flexible structures

NASA Technical Reports Server (NTRS)

Su, Tzu-Jeng; Craig, Roy R., Jr.

1990-01-01

A decentralized suboptimal linear quadratic control design procedure which combines substructural synthesis, model reduction, decentralized control design, subcontroller synthesis, and controller reduction is proposed for the design of reduced-order controllers for flexible structures. The procedure starts with a definition of the continuum structure to be controlled. An evaluation model of finite dimension is obtained by the finite element method. Then, the finite element model is decomposed into several substructures by using a natural decomposition called substructuring decomposition. Each substructure, at this point, still has too large a dimension and must be reduced to a size that is Riccati-solvable. Model reduction of each substructure can be performed by using any existing model reduction method, e.g., modal truncation, balanced reduction, Krylov model reduction, or mixed-mode method. Then, based on the reduced substructure model, a subcontroller is designed by an LQ optimal control method for each substructure independently. After all subcontrollers are designed, a controller synthesis method called substructural controller synthesis is employed to synthesize all subcontrollers into a global controller. The assembling scheme used is the same as that employed for the structure matrices. Finally, a controller reduction scheme, called the equivalent impulse response energy controller (EIREC) reduction algorithm, is used to reduce the global controller to a reasonable size for implementation. The EIREC reduced controller preserves the impulse response energy of the full-order controller and has the property of matching low-frequency moments and low-frequency power moments. An advantage of the substructural controller synthesis method is that it relieves the computational burden associated with dimensionality. Besides that, the SCS design scheme is also a highly adaptable controller synthesis method for structures with varying configuration, or varying mass and stiffness properties.

Lumber recovery and deterioration of beetle-killed douglas-fir and grand fir in the Blue Mountains of eastern Oregon. Forest Service general technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parry, D.L.; Filip, G.M.; Willits, S.A.

1996-09-01

The purpose of this study was to determine the effect of time since death over a 4-year period on the amount of usable product volume and value, and to determine the species of fungi associated with wood deterioration in the stems of Douglas-fir and grand fir trees killed by bark beetles in northeastern Oregon.

Growth of suppressed grand fir and Shasta red fir in central Oregon after release and thinning—10-year results.

Treesearch

Kenneth W. Seidel

1983-01-01

A 43-year-old, even-aged stand of advance reproduction of grand fir and Shasta red fir in central Oregon responded to release and thinning with diameter and height growth two to three times the prerelease rate. The response began immediately after the overstory was killed with 2,4-D. Diameter growth during the second 5 years after release increased significantly over...

Lumber recovery and deterioration of beetle-killed Douglas-fir and grand fir in the Blue Mountains of eastern Oregon.

Treesearch

Dean L. Parry; Gregory M. Filip; Susan A. Willits; Catherine G. Parks

1996-01-01

The purpose of this study was to determine the effect of time since death over a 4-year period on the amount of usable product volume and value, and to determine the species of fungi associated with wood deterioration in the stems of Douglas-fir and grand fir trees killed by bark beetles in northeastern Oregon. Sap rot, caused principally by Cryptoporus...

Tunable far infrared laser spectrometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blake, G.A.; Laughlin, K.B.; Cohen, R.C.

The state of the art in far infrared (FIR) spectroscopy is reviewed. The development of tunable, coherent FIR radiation sources is discussed. Applications of tunable FIR laser spectrometers for measurement of rotational spectra and dipole moments of molecular ions and free radicals, vibration-rotation-tunneling (VRT) spectra of weakly bound complexes, and vibration-rotation spectra of linear carbon clusters are presented. A detailed description of the Berkeley tunable FIR laser spectrometers is presented in the following article.

Comparison between hybrid feedforward-feedback, feedforward, and feedback structures for active noise control of fMRI noise.

PubMed

Reddy, Rajiv M; Panahi, Issa M S

2008-01-01

The performance of FIR feedforward, IIR feedforward, FIR feedback, hybrid FIR feedforward--FIR feedback, and hybrid IIR feedforward - FIR feedback structures for active noise control (ANC) are compared for an fMRI noise application. The filtered-input normalized least squares (FxNLMS) algorithm is used to update the coefficients of the adaptive filters in all these structures. Realistic primary and secondary paths of an fMRI bore are used by estimating them on a half cylindrical acrylic bore of 0.76 m (D)x1.52 m (L). Detailed results of the performance of the ANC system are presented in the paper for each of these structures. We find that the IIR feedforward structure produces most of the performance improvement in the hybrid IIR feedforward - FIR feedback structure and adding the feedback structure becomes almost redundant in the case of fMRI noise.

Far infrared radiation (FIR): its biological effects and medical applications

PubMed Central

Vatansever, Fatma; Hamblin, Michael R.

2013-01-01

Far infrared (FIR) radiation (λ = 3–100 μm) is a subdivision of the electromagnetic spectrum that has been investigated for biological effects. The goal of this review is to cover the use of a further sub-division (3– 12 μm) of this waveband, that has been observed in both in vitro and in vivo studies, to stimulate cells and tissue, and is considered a promising treatment modality for certain medical conditions. Technological advances have provided new techniques for delivering FIR radiation to the human body. Specialty lamps and saunas, delivering pure FIR radiation (eliminating completely the near and mid infrared bands), have became safe, effective, and widely used sources to generate therapeutic effects. Fibers impregnated with FIR emitting ceramic nanoparticles and woven into fabrics, are being used as garments and wraps to generate FIR radiation, and attain health benefits from its effects. PMID:23833705

A Radio Study of the Ultra-luminous FIR Galaxy NGC 6240

NASA Astrophysics Data System (ADS)

Colbert, E.; Wilson, A. S.; Bland-Hawthorn, J.

1993-05-01

A number of galaxies observed in the IRAS mission are noted to emit ~ 99% of their bolometric flux in the FIR, with FIR luminosities in excess of 10(11) Lsun. The interacting galaxy NGC 6240 has often been referred to as the ``proto-typical'' ultra-luminous (L_FIR >~ 10(12) Lsun) FIR galaxy. The origin of the FIR excess remains a disputed subject in the literature. New observations of NGC 6240 were taken with the VLA at 20cm in the B-configuration, and at 3.6cm in the A-configuration. No significant radio emission was detected from or near the possible ultra-massive ``dark core'' hypothesized by Bland-Hawthorn et. al. (1991); however, approximately 30% of Seyfert galaxies have 20 cm radio luminosities weaker than the upper limit derived from the radio maps. The non-thermal radio emission from luminous FIR galaxies is tightly correlated with the FIR emission. Previous radio observations of NGC 6240 revealed two compact, steep-spectrum nuclear sources, nearly coincident with the two nuclear sources seen in optical images. The 2 images from the new VLA observations and 5 images from previous VLA observations are used to identify the morphological and spectral features of the strong, compact components in the nuclear regions (<~ 1.5 kpc; D=100 Mpc) and of the weaker ``clumps'' of diffuse emission south and west (>~ 3 kpc) from the nucleus. Feasible explanations for the radio emission are discussed. The models that have been proposed in the literature for the FIR excess of NGC 6240 are evaluated for consistency with the observed radio emission.

RADIO IMAGING OF THE NGC 2024 FIR 5/6 REGION: A HYPERCOMPACT H II REGION CANDIDATE IN ORION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Minho; Kang, Miju; Lee, Jeong-Eun, E-mail: minho@kasi.re.kr

The NGC 2024 FIR 5/6 region was observed in the 6.9 mm continuum with an angular resolution of about 1.5 arcsec. The 6.9 mm continuum map shows four compact sources, FIR 5w, 5e, 6c, and 6n, as well as an extended structure of the ionization front associated with the optical nebulosity. FIR 6c has a source size of about 0.4 arcsec or 150 AU. The spectral energy distribution (SED) of FIR 6c is peculiar: rising steeply around 6.9 mm and flat around 1 mm. The possibility of a hypercompact H II region is explored. If the millimeter flux of FIRmore » 6c comes from hot ionized gas heated by a single object at the center, the central object may be a B1 star of about 5800 solar luminosities and about 13 solar masses. The 6.9 mm continuum of FIR 6n may be a mixture of free-free emission and dust continuum emission. Archival data show that both FIR 6n and 6c exhibit water maser activity, suggesting the existence of shocked gas around them. The 6.9 mm continuum emission from FIR 5w has a size of about 1.8 arcsec or 760 AU. The SEDs suggest that the 6.9 mm emission of FIR 5w and 5e comes from dust, and the masses of the dense molecular gas are about 0.6 and 0.5 solar masses, respectively.« less

7 CFR 301.92-2 - Restricted, regulated, and associated articles; lists of proven hosts and associated plant taxa.

Code of Federal Regulations, 2012 CFR

2012-01-01

... willow *Sequoia sempervirens Coast redwood *Syringa vulgaris Lilac *Taxus baccata European yew... Phytophthora ramorum: Abies concolor White fir Abies grandis Grand fir Abies magnifica Red fir Acer circinatum...

7 CFR 301.92-2 - Restricted, regulated, and associated articles; lists of proven hosts and associated plant taxa.

Code of Federal Regulations, 2013 CFR

2013-01-01

... willow *Sequoia sempervirens Coast redwood *Syringa vulgaris Lilac *Taxus baccata European yew... Phytophthora ramorum: Abies concolor White fir Abies grandis Grand fir Abies magnifica Red fir Acer circinatum...

7 CFR 301.92-2 - Restricted, regulated, and associated articles; lists of proven hosts and associated plant taxa.

Code of Federal Regulations, 2014 CFR

2014-01-01

... willow *Sequoia sempervirens Coast redwood *Syringa vulgaris Lilac *Taxus baccata European yew... Phytophthora ramorum: Abies concolor White fir Abies grandis Grand fir Abies magnifica Red fir Acer circinatum...

7 CFR 301.92-2 - Restricted, regulated, and associated articles; lists of proven hosts and associated plant taxa.

Code of Federal Regulations, 2010 CFR

2010-01-01

... willow *Sequoia sempervirens Coast redwood *Syringa vulgaris Lilac *Taxus baccata European yew... Phytophthora ramorum: Abies concolor White fir Abies grandis Grand fir Abies magnifica Red fir Acer circinatum...

7 CFR 301.92-2 - Restricted, regulated, and associated articles; lists of proven hosts and associated plant taxa.

Code of Federal Regulations, 2011 CFR

2011-01-01

... willow *Sequoia sempervirens Coast redwood *Syringa vulgaris Lilac *Taxus baccata European yew... Phytophthora ramorum: Abies concolor White fir Abies grandis Grand fir Abies magnifica Red fir Acer circinatum...

Far-infrared properties of cluster galaxies

NASA Technical Reports Server (NTRS)

Bicay, M. D.; Giovanelli, R.

1987-01-01

Far-infrared properties are derived for a sample of over 200 galaxies in seven clusters: A262, Cancer, A1367, A1656 (Coma), A2147, A2151 (Hercules), and Pegasus. The IR-selected sample consists almost entirely of IR normal galaxies, with Log of L(FIR) = 9.79 solar luminosities, Log of L(FIR)/L(B) = 0,79, and Log of S(100 microns)/S(60 microns) = 0.42. None of the sample galaxies has Log of L(FIR) greater than 11.0 solar luminosities, and only one has a FIR-to-blue luminosity ratio greater than 10. No significant differences are found in the FIR properties of HI-deficient and HI-normal cluster galaxies.

A collocation--Galerkin finite element model of cardiac action potential propagation.

PubMed

Rogers, J M; McCulloch, A D

1994-08-01

A new computational method was developed for modeling the effects of the geometric complexity, nonuniform muscle fiber orientation, and material inhomogeneity of the ventricular wall on cardiac impulse propagation. The method was used to solve a modification to the FitzHugh-Nagumo system of equations. The geometry, local muscle fiber orientation, and material parameters of the domain were defined using linear Lagrange or cubic Hermite finite element interpolation. Spatial variations of time-dependent excitation and recovery variables were approximated using cubic Hermite finite element interpolation, and the governing finite element equations were assembled using the collocation method. To overcome the deficiencies of conventional collocation methods on irregular domains, Galerkin equations for the no-flux boundary conditions were used instead of collocation equations for the boundary degrees-of-freedom. The resulting system was evolved using an adaptive Runge-Kutta method. Converged two-dimensional simulations of normal propagation showed that this method requires less CPU time than a traditional finite difference discretization. The model also reproduced several other physiologic phenomena known to be important in arrhythmogenesis including: Wenckebach periodicity, slowed propagation and unidirectional block due to wavefront curvature, reentry around a fixed obstacle, and spiral wave reentry. In a new result, we observed wavespeed variations and block due to nonuniform muscle fiber orientation. The findings suggest that the finite element method is suitable for studying normal and pathological cardiac activation and has significant advantages over existing techniques.

Tree-ring stable isotopes record the impact of a foliar fungal pathogen on CO(2) assimilation and growth in Douglas-fir.

PubMed

Saffell, Brandy J; Meinzer, Frederick C; Voelker, Steven L; Shaw, David C; Brooks, J Renée; Lachenbruch, Barbara; McKay, Jennifer

2014-07-01

Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible reference species (western hemlock, Tsuga heterophylla) to evaluate their use as proxies for variation in past SNC infection, particularly in relation to potential explanatory climate factors. We sampled trees from an Oregon site where a fungicide trial took place from 1996 to 2000, which enabled the comparison of stable isotope values between trees with and without disease. Carbon stable isotope discrimination (Δ(13)C) of treated Douglas-fir tree-rings was greater than that of untreated Douglas-fir tree-rings during the fungicide treatment period. Both annual growth and tree-ring Δ(13)C increased with treatment such that treated Douglas-fir had values similar to co-occurring western hemlock during the treatment period. There was no difference in the tree-ring oxygen stable isotope ratio between treated and untreated Douglas-fir. Tree-ring Δ(13)C of diseased Douglas-fir was negatively correlated with relative humidity during the two previous summers, consistent with increased leaf colonization by SNC under high humidity conditions that leads to greater disease severity in following years. © 2013 John Wiley & Sons Ltd.

Far-infrared suppresses skin photoaging in ultraviolet B-exposed fibroblasts and hairless mice

PubMed Central

Chiu, Hui-Wen; Chen, Cheng-Hsien; Chen, Yi-Jie; Hsu, Yung-Ho

2017-01-01

Ultraviolet (UV) induces skin photoaging, which is characterized by thickening, wrinkling, pigmentation, and dryness. Collagen, which is one of the main building blocks of human skin, is regulated by collagen synthesis and collagen breakdown. Autophagy was found to block the epidermal hyperproliferative response to UVB and may play a crucial role in preventing skin photoaging. In the present study, we investigated whether far-infrared (FIR) therapy can inhibit skin photoaging via UVB irradiation in NIH 3T3 mouse embryonic fibroblasts and SKH-1 hairless mice. We found that FIR treatment significantly increased procollagen type I through the induction of the TGF-β/Smad axis. Furthermore, UVB significantly enhanced the expression of matrix metalloproteinase-1 (MMP-1) and MMP-9. FIR inhibited UVB-induced MMP-1 and MMP-9. Treatment with FIR reversed UVB-decreased type I collagen. In addition, FIR induced autophagy by inhibiting the Akt/mTOR signaling pathway. In UVB-induced skin photoaging in a hairless mouse model, FIR treatment resulted in decreased skin thickness in UVB irradiated mice and inhibited the degradation of collagen fibers. Moreover, FIR can increase procollagen type I via the inhibition of MMP-9 and induction of TGF-β in skin tissues. Therefore, our study provides evidence for the beneficial effects of FIR exposure in a model of skin photoaging. PMID:28301572

Harmonised information exchange between decentralised food composition database systems.

PubMed

Pakkala, H; Christensen, T; de Victoria, I Martínez; Presser, K; Kadvan, A

2010-11-01

The main aim of the European Food Information Resource (EuroFIR) project is to develop and disseminate a comprehensive, coherent and validated data bank for the distribution of food composition data (FCD). This can only be accomplished by harmonising food description and data documentation and by the use of standardised thesauri. The data bank is implemented through a network of local FCD storages (usually national) under the control and responsibility of the local (national) EuroFIR partner. The implementation of the system based on the EuroFIR specifications is under development. The data interchange happens through the EuroFIR Web Services interface, allowing the partners to implement their system using methods and software suitable for the local computer environment. The implementation uses common international standards, such as Simple Object Access Protocol, Web Service Description Language and Extensible Markup Language (XML). A specifically constructed EuroFIR search facility (eSearch) was designed for end users. The EuroFIR eSearch facility compiles queries using a specifically designed Food Data Query Language and sends a request to those network nodes linked to the EuroFIR Web Services that will most likely have the requested information. The retrieved FCD are compiled into a specifically designed data interchange format (the EuroFIR Food Data Transport Package) in XML, which is sent back to the EuroFIR eSearch facility as the query response. The same request-response operation happens in all the nodes that have been selected in the EuroFIR eSearch facility for a certain task. Finally, the FCD are combined by the EuroFIR eSearch facility and delivered to the food compiler. The implementation of FCD interchange using decentralised computer systems instead of traditional data-centre models has several advantages. First of all, the local partners have more control over their FCD, which will increase commitment and improve quality. Second, a multicentred solution is more economically viable than the creation of a centralised data bank, because of the lack of national political support for multinational systems.

MHD Energy Bypass Scramjet Performance with Real Gas Effects

NASA Technical Reports Server (NTRS)

Park, Chul; Mehta, Unmeel B.; Bogdanoff, David W.

2000-01-01

The theoretical performance of a scramjet propulsion system incorporating an magneto-hydro-dynamic (MHD) energy bypass scheme is calculated. The one-dimensional analysis developed earlier, in which the theoretical performance is calculated neglecting skin friction and using a sudden-freezing approximation for the nozzle flow, is modified to incorporate the method of Van Driest for turbulent skin friction and a finite-rate chemistry calculation in the nozzle. Unlike in the earlier design, in which four ramp compressions occurred in the pitch plane, in the present design the first two ramp compressions occur in the pitch plane and the next two compressions occur in the yaw plane. The results for the simplified design of a spaceliner show that (1) the present design produces higher specific impulses than the earlier design, (2) skin friction substantially reduces thrust and specific impulse, and (3) the specific impulse of the MHD-bypass system is still better than the non-MHD system and typical rocket over a narrow region of flight speeds and design parameters. Results suggest that the energy management with MHD principles offers the possibility of improving the performance of the scramjet. The technical issues needing further studies are identified.

Crosswell electromagnetic modeling from impulsive source: Optimization strategy for dispersion suppression in convolutional perfectly matched layer

PubMed Central

Fang, Sinan; Pan, Heping; Du, Ting; Konaté, Ahmed Amara; Deng, Chengxiang; Qin, Zhen; Guo, Bo; Peng, Ling; Ma, Huolin; Li, Gang; Zhou, Feng

2016-01-01

This study applied the finite-difference time-domain (FDTD) method to forward modeling of the low-frequency crosswell electromagnetic (EM) method. Specifically, we implemented impulse sources and convolutional perfectly matched layer (CPML). In the process to strengthen CPML, we observed that some dispersion was induced by the real stretch κ, together with an angular variation of the phase velocity of the transverse electric plane wave; the conclusion was that this dispersion was positively related to the real stretch and was little affected by grid interval. To suppress the dispersion in the CPML, we first derived the analytical solution for the radiation field of the magneto-dipole impulse source in the time domain. Then, a numerical simulation of CPML absorption with high-frequency pulses qualitatively amplified the dispersion laws through wave field snapshots. A numerical simulation using low-frequency pulses suggested an optimal parameter strategy for CPML from the established criteria. Based on its physical nature, the CPML method of simply warping space-time was predicted to be a promising approach to achieve ideal absorption, although it was still difficult to entirely remove the dispersion. PMID:27585538

On the nonlinear stability of viscous modes within the Rayleigh problem on an infinite flat plate

NASA Technical Reports Server (NTRS)

Webb, J. C.; Otto, S. R.; Lilley, G. M.

1994-01-01

The stability has been investigated of the unsteady flow past an infinite flat plate when it is moved impulsively from rest, in its own plane. For small times the instantaneous stability of the flow depends on the linearized equations of motion which reduce in this problem to the Orr-Sommerfeld equation. It is known that the flow for certain values of Reynolds number, frequency and wave number is unstable to Tollmien-Schlichting waves, as in the case of the Blasius boundary layer flow past a flat plate. With increase in time, the unstable waves only undergo growth for a finite time interval, and this growth rate is itself a function of time. The influence of finite amplitude effects is studied by solving the full Navier-Stokes equations. It is found that the stability characteristics are markedly changed both by the consideration of the time evolution of the flow, and by the introduction of finite amplitude effects.

Assessment of the performance of rigid pavement back-calculation through finite element modeling

NASA Astrophysics Data System (ADS)

Shoukry, Samir N.; William, Gergis W.; Martinelli, David R.

1999-02-01

This study focuses on examining the behavior of rigid pavement layers during the Falling Weight Deflectometer (FWD) test. Factors affecting the design of a concrete slab, such as whether the joints are doweled or undoweled and the spacing between the transverse joints, were considered in this study. Explicit finite element analysis was employed to investigate pavement layers' responses to the action of the impulse of the FWD test. Models of various dimensions were developed to satisfy the factors under consideration. The accuracy of the finite element models developed in this investigation was verified by comparing the finite element- generated deflection basin with that experimentally measured during an actual test. The results showed that the measured deflection basin can be reproduced through finite element modeling of the pavement structure. The resulting deflection basins from the use FE modeling was processed in order to backcalculate pavement layer moduli. This approach provides a method for the evaluation of the performance of existing backcalculation programs which are based on static elastic layer analysis. Based upon the previous studies conducted for the selection of software, three different backcalculation programs were chosen for the evaluation: MODULUS5.0, EVERCALC4.0, and MODCOMP3. The results indicate that ignoring the dynamic nature of the load may lead to crude results, especially during backcalculation procedures.

A SNP resource for Douglas-fir: de novo transcriptome assembly and SNP detection and validation.

PubMed

Howe, Glenn T; Yu, Jianbin; Knaus, Brian; Cronn, Richard; Kolpak, Scott; Dolan, Peter; Lorenz, W Walter; Dean, Jeffrey F D

2013-02-28

Douglas-fir (Pseudotsuga menziesii), one of the most economically and ecologically important tree species in the world, also has one of the largest tree breeding programs. Although the coastal and interior varieties of Douglas-fir (vars. menziesii and glauca) are native to North America, the coastal variety is also widely planted for timber production in Europe, New Zealand, Australia, and Chile. Our main goal was to develop a SNP resource large enough to facilitate genomic selection in Douglas-fir breeding programs. To accomplish this, we developed a 454-based reference transcriptome for coastal Douglas-fir, annotated and evaluated the quality of the reference, identified putative SNPs, and then validated a sample of those SNPs using the Illumina Infinium genotyping platform. We assembled a reference transcriptome consisting of 25,002 isogroups (unique gene models) and 102,623 singletons from 2.76 million 454 and Sanger cDNA sequences from coastal Douglas-fir. We identified 278,979 unique SNPs by mapping the 454 and Sanger sequences to the reference, and by mapping four datasets of Illumina cDNA sequences from multiple seed sources, genotypes, and tissues. The Illumina datasets represented coastal Douglas-fir (64.00 and 13.41 million reads), interior Douglas-fir (80.45 million reads), and a Yakima population similar to interior Douglas-fir (8.99 million reads). We assayed 8067 SNPs on 260 trees using an Illumina Infinium SNP genotyping array. Of these SNPs, 5847 (72.5%) were called successfully and were polymorphic. Based on our validation efficiency, our SNP database may contain as many as ~200,000 true SNPs, and as many as ~69,000 SNPs that could be genotyped at ~20,000 gene loci using an Infinium II array-more SNPs than are needed to use genomic selection in tree breeding programs. Ultimately, these genomic resources will enhance Douglas-fir breeding and allow us to better understand landscape-scale patterns of genetic variation and potential responses to climate change.

A SNP resource for Douglas-fir: de novo transcriptome assembly and SNP detection and validation

PubMed Central

2013-01-01

Background Douglas-fir (Pseudotsuga menziesii), one of the most economically and ecologically important tree species in the world, also has one of the largest tree breeding programs. Although the coastal and interior varieties of Douglas-fir (vars. menziesii and glauca) are native to North America, the coastal variety is also widely planted for timber production in Europe, New Zealand, Australia, and Chile. Our main goal was to develop a SNP resource large enough to facilitate genomic selection in Douglas-fir breeding programs. To accomplish this, we developed a 454-based reference transcriptome for coastal Douglas-fir, annotated and evaluated the quality of the reference, identified putative SNPs, and then validated a sample of those SNPs using the Illumina Infinium genotyping platform. Results We assembled a reference transcriptome consisting of 25,002 isogroups (unique gene models) and 102,623 singletons from 2.76 million 454 and Sanger cDNA sequences from coastal Douglas-fir. We identified 278,979 unique SNPs by mapping the 454 and Sanger sequences to the reference, and by mapping four datasets of Illumina cDNA sequences from multiple seed sources, genotypes, and tissues. The Illumina datasets represented coastal Douglas-fir (64.00 and 13.41 million reads), interior Douglas-fir (80.45 million reads), and a Yakima population similar to interior Douglas-fir (8.99 million reads). We assayed 8067 SNPs on 260 trees using an Illumina Infinium SNP genotyping array. Of these SNPs, 5847 (72.5%) were called successfully and were polymorphic. Conclusions Based on our validation efficiency, our SNP database may contain as many as ~200,000 true SNPs, and as many as ~69,000 SNPs that could be genotyped at ~20,000 gene loci using an Infinium II array—more SNPs than are needed to use genomic selection in tree breeding programs. Ultimately, these genomic resources will enhance Douglas-fir breeding and allow us to better understand landscape-scale patterns of genetic variation and potential responses to climate change. PMID:23445355

The Fluids Integrated Rack and Light Microscopy Module Integrated Capabilities

NASA Technical Reports Server (NTRS)

Motil, Susan M.; Gati, Frank; Snead, John H.; Hill, Myron E.; Griffin, DeVon W.

2003-01-01

The Fluids Integrated Rack (FIR), a facility class payload, and the Light Microscopy Module (LMM), a subrack payload, are scheduled to be launched in 2005. The LMM integrated into the FIR will provide a unique platform for conducting fluids and biological experiments on ISS. The FIR is a modular, multi-user scientific research facility that will fly in the U.S. laboratory module, Destiny, of the International Space Station (ISS). The first payload in the FIR will be the Light Microscopy Module (LMM). The LMM is planned as a remotely controllable, automated, on-orbit microscope subrack facility, allowing flexible scheduling and control of fluids and biology experiments within the FIR. Key diagnostic capabilities for meeting science requirements include video microscopy to observe microscopic phenomena and dynamic interactions, interferometry to make thin film measurements with nanometer resolution, laser tweezers for particle manipulation, confocal microscopy to provide enhanced three-dimensional visualization of structures, and spectrophotometry to measure photonic properties of materials. The LMM also provides experiment sample containment for frangibles and fluids. This paper will provide a description of the current FIR and LMM designs, planned capabilities and key features. In addition a brief description of the initial five experiments planned for LMM/FIR will be provided.

Global dynamics of a stochastic neuronal oscillator

NASA Astrophysics Data System (ADS)

Yamanobe, Takanobu

2013-11-01

Nonlinear oscillators have been used to model neurons that fire periodically in the absence of input. These oscillators, which are called neuronal oscillators, share some common response structures with other biological oscillations such as cardiac cells. In this study, we analyze the dependence of the global dynamics of an impulse-driven stochastic neuronal oscillator on the relaxation rate to the limit cycle, the strength of the intrinsic noise, and the impulsive input parameters. To do this, we use a Markov operator that both reflects the density evolution of the oscillator and is an extension of the phase transition curve, which describes the phase shift due to a single isolated impulse. Previously, we derived the Markov operator for the finite relaxation rate that describes the dynamics of the entire phase plane. Here, we construct a Markov operator for the infinite relaxation rate that describes the stochastic dynamics restricted to the limit cycle. In both cases, the response of the stochastic neuronal oscillator to time-varying impulses is described by a product of Markov operators. Furthermore, we calculate the number of spikes between two consecutive impulses to relate the dynamics of the oscillator to the number of spikes per unit time and the interspike interval density. Specifically, we analyze the dynamics of the number of spikes per unit time based on the properties of the Markov operators. Each Markov operator can be decomposed into stationary and transient components based on the properties of the eigenvalues and eigenfunctions. This allows us to evaluate the difference in the number of spikes per unit time between the stationary and transient responses of the oscillator, which we show to be based on the dependence of the oscillator on past activity. Our analysis shows how the duration of the past neuronal activity depends on the relaxation rate, the noise strength, and the impulsive input parameters.

Global dynamics of a stochastic neuronal oscillator.

PubMed

Yamanobe, Takanobu

2013-11-01

Nonlinear oscillators have been used to model neurons that fire periodically in the absence of input. These oscillators, which are called neuronal oscillators, share some common response structures with other biological oscillations such as cardiac cells. In this study, we analyze the dependence of the global dynamics of an impulse-driven stochastic neuronal oscillator on the relaxation rate to the limit cycle, the strength of the intrinsic noise, and the impulsive input parameters. To do this, we use a Markov operator that both reflects the density evolution of the oscillator and is an extension of the phase transition curve, which describes the phase shift due to a single isolated impulse. Previously, we derived the Markov operator for the finite relaxation rate that describes the dynamics of the entire phase plane. Here, we construct a Markov operator for the infinite relaxation rate that describes the stochastic dynamics restricted to the limit cycle. In both cases, the response of the stochastic neuronal oscillator to time-varying impulses is described by a product of Markov operators. Furthermore, we calculate the number of spikes between two consecutive impulses to relate the dynamics of the oscillator to the number of spikes per unit time and the interspike interval density. Specifically, we analyze the dynamics of the number of spikes per unit time based on the properties of the Markov operators. Each Markov operator can be decomposed into stationary and transient components based on the properties of the eigenvalues and eigenfunctions. This allows us to evaluate the difference in the number of spikes per unit time between the stationary and transient responses of the oscillator, which we show to be based on the dependence of the oscillator on past activity. Our analysis shows how the duration of the past neuronal activity depends on the relaxation rate, the noise strength, and the impulsive input parameters.

Robust stochastic resonance: Signal detection and adaptation in impulsive noise

NASA Astrophysics Data System (ADS)

Kosko, Bart; Mitaim, Sanya

2001-11-01

Stochastic resonance (SR) occurs when noise improves a system performance measure such as a spectral signal-to-noise ratio or a cross-correlation measure. All SR studies have assumed that the forcing noise has finite variance. Most have further assumed that the noise is Gaussian. We show that SR still occurs for the more general case of impulsive or infinite-variance noise. The SR effect fades as the noise grows more impulsive. We study this fading effect on the family of symmetric α-stable bell curves that includes the Gaussian bell curve as a special case. These bell curves have thicker tails as the parameter α falls from 2 (the Gaussian case) to 1 (the Cauchy case) to even lower values. Thicker tails create more frequent and more violent noise impulses. The main feedback and feedforward models in the SR literature show this fading SR effect for periodic forcing signals when we plot either the signal-to-noise ratio or a signal correlation measure against the dispersion of the α-stable noise. Linear regression shows that an exponential law γopt(α)=cAα describes this relation between the impulsive index α and the SR-optimal noise dispersion γopt. The results show that SR is robust against noise ``outliers.'' So SR may be more widespread in nature than previously believed. Such robustness also favors the use of SR in engineering systems. We further show that an adaptive system can learn the optimal noise dispersion for two standard SR models (the quartic bistable model and the FitzHugh-Nagumo neuron model) for the signal-to-noise ratio performance measure. This also favors practical applications of SR and suggests that evolution may have tuned the noise-sensitive parameters of biological systems.

Price projections for selected grades of Douglas-fir lumber.

Treesearch

Richard W. Haynes; Thomas D. Fahey; Roger D. Fight

1988-01-01

Grade-specific price projections were developed for Douglas-fir lumber produced in the Douglas-fir region. These grade-specific price projections can be used as an aid in evaluating management practices that will affect the quality of saw logs that are produced.

Predictions of fire behavior and resistance to control: for use with photo series for the Douglas fir-hemlock type and the coastal Douglas-fir-hardwood type.

Treesearch

David V. SANDBERG; Franklin R. Ward

1981-01-01

This publication presents tables on the behavior of fire and the resistance of fuels to control. The information is to be used with the photos in the publication, "Photo Series for Quantifying Forest Residues in the Coastal Douglas-fir—Hemlock Type, Coastal Douglas-fir—Hardwood Type" (Maxwell, Wayne G.; Ward, Franklin R. 1976. Gen. Tech. Rep. PNW-GTR-051....

Modelling based on Spatial Impulse Response Model for Optimization of Inter Digital Transducers (SAW Sensors) for Non Destructive Testing

NASA Astrophysics Data System (ADS)

Fall, D.; Duquennoy, M.; Ouaftouh, M.; Piwakowski, B.; Jenot, F.

This study deals with modelling SAW-IDT transducers for their optimization. These sensors are specifically developed to characterize properties of thin layers, coatings and functional surfaces. Among the methods of characterization, the ultrasonic methods using Rayleigh surface waves are particularly interesting because the propagation of these waves is close to the surface of material and the energy is concentrated within a layer under the surface of about one wavelength thick. In order to characterize these coatings and structures, it is necessary to work in high frequencies, this is why in this study, SAW-IDT sensors are realized for surface acoustic wave generation. For optimization of these SAW-IDT sensors, particularly their band-width, it is necessary to study various IDT configurations by varying the number of electrodes, dimensions of the electrodes, their shapes and spacings. Thus it is necessary to implement effective and rapid technique for modelling. The originality of this study is to develop simulation tools based on Spatial Impulse Response model. Therefore it will be possible to reduce considerably computing time and results are obtained in a few seconds, instead of several hours (or days) by using finite element method. In order to validate this method, theoretical and experimental results are compared with finite element method and Interferometric measurements. The results obtained show a good overall concordance and confirm effectiveness of suggested method.

Litter dynamics in two Sierran mixed conifer forests. I. Litterfall and decomposition rates

USGS Publications Warehouse

Stohlgren, Thomas J.

1988-01-01

Litterfall was measured for 4 years and leaf litter decomposition rates were studied for 3.6 years in two mixed conifer forest (giant sequoia-fir and fir-pine) in the southern Sierra Nevada of California. The giant sequoia-fir forest (GS site) was dominated by giant sequoia (Sequoiadendron giganteum (Lindl.) Buchh.), white fir (Abies concolor Lindl. & Gord.), and sugar pine (Pinus lambertiana Dougl.). The fir-pine forest (FP site) was dominated by white fir, sugar pine, and incense cedar (Calocedrus decurrens (Torr.) Florin). Litterfall, including large woody debris -1•year-1 compared with 4355 kg•ha-1•year-1 at the FP site (3.4:1). In the GS site, leaf litter decomposition after 3.6 years was slowest for giant sequoia (28.2% mass loss), followed by sugar pine (34.3%) and white fie (45.1%). In the FP site, mass loss was slowest for sugar pine (40.0%), followed by white fir (45.1%), while incense cedar showed the greatest mass loss (56.9%) after 3.6 years. High litterfall rates of large woody debris (i.e., 2.5-15.2 cm diameter) and slow rates of leaf litter decomposition in the giant sequoia-fir forest type may result in higher litter accumulation rates than in the fir-pine type. Leaf litter times to 95% decay for the GS and FP sites were 30 and 27 years, respectively, if the initial 0.7-year period (a short period of rapid mass decay) was ignored in the calculation. A mass balance approach for total litterfall (<15.2 cm diameter) decomposition yielded lower decay constants than did the litterbag study and therefore longer times to 95% decay (57 years for the GS site and 62 years for the FP site).

Experimental and analytical comparison of flowfields in a 110 N (25 lbf) H2/O2 rocket

NASA Technical Reports Server (NTRS)

Reed, Brian D.; Penko, Paul F.; Schneider, Steven J.; Kim, Suk C.

1991-01-01

A gaseous hydrogen/gaseous oxygen 110 N (25 lbf) rocket was examined through the RPLUS code using the full Navier-Stokes equations with finite rate chemistry. Performance tests were conducted on the rocket in an altitude test facility. Preliminary parametric analyses were performed for a range of mixture ratios and fuel film cooling pcts. It is shown that the computed values of specific impulse and characteristic exhaust velocity follow the trend of the experimental data. Specific impulse computed by the code is lower than the comparable test values by about two to three percent. The computed characteristic exhaust velocity values are lower than the comparable test values by three to four pct. Thrust coefficients computed by the code are found to be within two pct. of the measured values. It is concluded that the discrepancy between computed and experimental performance values could not be attributed to experimental uncertainty.

Deflection corridors of abdomen and thorax in oblique side impacts using equal stress equal velocity approach: comparison with other normalization methods.

PubMed

Yoganandan, Narayan; Arun, Mike W J; Humm, John; Pintar, Frank A

2014-10-01

The first objective of the study was to determine the thorax and abdomen deflection time corridors using the equal stress equal velocity approach from oblique side impact sled tests with postmortem human surrogates fitted with chestbands. The second purpose of the study was to generate deflection time corridors using impulse momentum methods and determine which of these methods best suits the data. An anthropometry-specific load wall was used. Individual surrogate responses were normalized to standard midsize male anthropometry. Corridors from the equal stress equal velocity approach were very similar to those from impulse momentum methods, thus either method can be used for this data. Present mean and plus/minus one standard deviation abdomen and thorax deflection time corridors can be used to evaluate dummies and validate complex human body finite element models.

Loss Factor Estimation Using the Impulse Response Decay Method on a Stiffened Structure

NASA Technical Reports Server (NTRS)

Cabell, Randolph; Schiller, Noah; Allen, Albert; Moeller, Mark

2009-01-01

High-frequency vibroacoustic modeling is typically performed using energy-based techniques such as Statistical Energy Analysis (SEA). Energy models require an estimate of the internal damping loss factor. Unfortunately, the loss factor is difficult to estimate analytically, and experimental methods such as the power injection method can require extensive measurements over the structure of interest. This paper discusses the implications of estimating damping loss factors using the impulse response decay method (IRDM) from a limited set of response measurements. An automated procedure for implementing IRDM is described and then evaluated using data from a finite element model of a stiffened, curved panel. Estimated loss factors are compared with loss factors computed using a power injection method and a manual curve fit. The paper discusses the sensitivity of the IRDM loss factor estimates to damping of connected subsystems and the number and location of points in the measurement ensemble.

Impulse generation by detonation tubes

NASA Astrophysics Data System (ADS)

Cooper, Marcia Ann

Impulse generation with gaseous detonation requires conversion of chemical energy into mechanical energy. This conversion process is well understood in rocket engines where the high pressure combustion products expand through a nozzle generating high velocity exhaust gases. The propulsion community is now focusing on advanced concepts that utilize non-traditional forms of combustion like detonation. Such a device is called a pulse detonation engine in which laboratory tests have proven that thrust can be achieved through continuous cyclic operation. Because of poor performance of straight detonation tubes compared to conventional propulsion systems and the success of using nozzles on rocket engines, the effect of nozzles on detonation tubes is being investigated. Although previous studies of detonation tube nozzles have suggested substantial benefits, up to now there has been no systematic investigations over a range of operating conditions and nozzle configurations. As a result, no models predicting the impulse when nozzles are used exist. This lack of data has severely limited the development and evaluation of models and simulations of nozzles on pulse detonation engines. The first experimental investigation measuring impulse by gaseous detonation in plain tubes and tubes with nozzles operating in varying environment pressures is presented. Converging, diverging, and converging-diverging nozzles were tested to determine the effect of divergence angle, nozzle length, and volumetric fill fraction on impulse. The largest increases in specific impulse, 72% at an environment pressure of 100 kPa and 43% at an environment pressure of 1.4 kPa, were measured with the largest diverging nozzle tested that had a 12° half angle and was 0.6 m long. Two regimes of nozzle operation that depend on the environment pressure are responsible for these increases and were first observed from these data. To augment this experimental investigation, all data in the literature regarding partially filled detonation tubes was compiled and analyzed with models investigating concepts of energy conservation and unsteady gas dynamics. A model to predict the specific impulse was developed for partially filled tubes. The role of finite chemical kinetics in detonation products was examined through numerical simulations of the flow in nonsteady expansion waves.

Aboveground growth interactions of paired conifer seedlings in close proximity

Treesearch

Warren D. Devine; Timothy B. Harrington

2011-01-01

Where belowground resources are relatively abundant, naturally established trees sometimes occur in very close proximity to one another. We conducted a two-year study to assess the aboveground interactions between Douglas-fir (Pseudotsuga menziesii), grand fir (Abies grandis) and noble fir (Abies procera)...

Early genetic testing of coastal Douglas-fir for Swiss needle cast tolerance.

Treesearch

Fatih Temel; G.R. Johnson; W.T. Adams

2005-01-01

The possibility of early testing coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) for Swiss needle cast (SNC; caused by Phaeocryptopus gaeumannii (Rohde) Petrak) tolerance was investigated using 55 Douglas-fir families from western Oregon. Seedlings were inoculated with P...

Technology Development of Miniaturized Far-Infrared Sources for Biomolecular Spectroscopy

NASA Technical Reports Server (NTRS)

Kono, Junichiro

2003-01-01

The objective of this project was to develop a purely solid-state based, thus miniaturized, far-infrared (FIR) (also known as terahertz (THz)) wave source using III-V semiconductor nanostructures for biomolecular detection and sensing. Many biomolecules, such as DNA and proteins, have distinct spectroscopic features in the FIR wavelength range as a result of vibration-rotation-tunneling motions and various inter- and intra-molecule collective motions. Spectroscopic characterization of such molecules requires narrow linewidth, sufficiently high power, tunable (in wavelength), and coherent FIR sources. Unfortunately, the FIR frequency is one of the least technologically developed ranges in the electromagnetic spectrum. Currently available FIR sources based on non-solid state technology are bulky, inefficient, and very often incoherent. In this project we investigated antimonide based compound semiconductor (ABCS) nanostructures as the active medium to generate FIR radiation. The final goal of this project was to demonstrate a semiconductor THz source integrated with a pumping diode laser module to achieve a compact system for biomolecular applications.

Spectral Energy Distribution of Far-infrared Bright Quasar Sample in the Lockman Hole

NASA Astrophysics Data System (ADS)

Dai, Y.; Huang, J.-S.; Omont, A.; Hatziminaoglou, E.; Willmer, C.; Fazio, G.; Elvis, M.; Bergeron, J.; Rigopoulou, D.; Perez-Fournon, I.

2011-10-01

The far-infrared (FIR) properties of Quasi-Stellar Objects (QSOs) is important in connecting the Starburst (SB) and Active Galactic Nucleus (AGN) activities. Therefore, we constructed a 24 μ m selected QSO sample to study their FIR behavior. All sources were spectroscopically identified from MMT or the Sloan Digital Sky Survey (SDSS) as broadline quasars. Of the total ˜330 sources, 37 have secure FIR detections in the Herschel-HERMES field. We compared their SEDs to previous QSO templates, and found that those FIR bright quasars differ from existing AGNs only by an additional dust component(s). Further studies on the origin for the FIR emission reveals the relative roles starburst and AGN play in powering the dust emission, based on the dust temperature, FIR luminosity, and the shapes of individual SEDs. The dust temperatures have a wide range from 20K to 80K with a median of ˜ 30K, indicating homogeneous heating mechanisms that could later be related to the origin of these cold dust emissions.

Local Volume Hi Survey: the far-infrared radio correlation

NASA Astrophysics Data System (ADS)

Shao, Li; Koribalski, Bärbel S.; Wang, Jing; Ho, Luis C.; Staveley-Smith, Lister

2018-06-01

In this paper we measure the far-infrared (FIR) and radio flux densities of a sample of 82 local gas-rich galaxies, including 70 "dwarf" galaxies (M* < 109 M⊙), from the Local Volume HI Survey (LVHIS), which is close to volume limited. It is found that LVHIS galaxies hold a tight linear FIR-radio correlation (FRC) over four orders of magnitude (F_1.4GHz ∝ F_FIR^{1.00± 0.08}). However, for detected galaxies only, a trend of larger FIR-to-radio ratio with decreasing flux density is observed. We estimate the star formation rate by combining UV and mid-IR data using empirical calibration. It is confirmed that both FIR and radio emission are strongly connected with star formation but with significant non-linearity. Dwarf galaxies are found radiation deficient in both bands, when normalized by star formation rate. It urges a "conspiracy" to keep the FIR-to-radio ratio generally constant. By using partial correlation coefficient in Pearson definition, we identify the key galaxy properties associated with the FIR and radio deficiency. Some major factors, such as stellar mass surface density, will cancel out when taking the ratio between FIR and radio fluxes. The remaining factors, such as HI-to-stellar mass ratio and galaxy size, are expected to cancel each other due to the distribution of galaxies in the parameter space. Such cancellation is probably responsible for the "conspiracy" to keep the FRC alive.

Fir Decline and Mortality in the Southern Siberian Mountains

NASA Technical Reports Server (NTRS)

Kharuk, Viacheslav I.; Im, Sergei T.; Petrov, Ilya A.; Dvinskaya, Mariya, L.; Fedotova, Elena V.; Ranson, Kenneth J.

2016-01-01

Increased dieback and mortality of dark needle conifer (DNC) stands (composed of fir (Abies sibirica),Siberian pine (Pinus sibirica) and spruce (Picea obovata))were documented in Russia during recent decades. Here we analyzed spatial and temporal patterns of fir decline and mortality in the southern Siberian Mountains based on satellite, in situ and dendrochronological data. The studied stands are located within the boundary between DNC taiga to the north and forest-steppe to the south. Fir decline and mortality were observed to originate where topographic features contributed to maximal water-stress risk, i.e., steep (1825),convex, south-facing slopes with a shallow well-drained root zone. Fir regeneration survived droughts and increased stem radial growth, while upper canopy trees died. Tree ring width(TRW) growth negatively correlated with vapor pressure deficit (VPD), drought index and occurrence of late frosts, and positively with soil water content. Previous year growth conditions (i.e., drought index, VPD, soil water anomalies)have a high impact on current TRW (r 0.600.74). Fir mortality was induced by increased water stress and severe droughts (as a primary factor) in synergy with bark-beetles and fungi attacks (as secondary factors). Dendrochronology data indicated that fir mortality is a periodic process. In a future climate with increased aridity and drought frequency, fir (and Siberian pine) may disappear from portions of its current range (primarily within the boundary with the forest steppe)and is likely to be replaced by drought-tolerant species such as Pinus sylvestris and Larix sibirica.

Effects of channel tap spacing on delay-lock tracking

NASA Astrophysics Data System (ADS)

Dana, Roger A.; Milner, Brian R.; Bogusch, Robert L.

1995-12-01

High fidelity simulations of communication links operating through frequency selective fading channels require both accurate channel models and faithful reproduction of the received signal. In modern radio receivers, processing beyond the analog-to-digital converter (A/D) is done digitally, so a high fidelity simulation is actually an emulation of this digital signal processing. The 'simulation' occurs in constructing the output of the A/D. One approach to constructing the A/D output is to convolve the channel impulse response function with the combined impulse response of the transmitted modulation and the A/D. For both link simulations and hardware channel simulators, the channel impulse response function is then generated with a finite number of samples per chip, and the convolution is implemented in a tapped delay line. In this paper we discuss the effects of the channel model tap spacing on the performance of delay locked loops (DLLs) in both direct sequence and frequency hopped spread spectrum systems. A frequency selective fading channel is considered, and the channel impulse response function is constructed with an integer number of taps per modulation symbol or chip. The tracking loop time delay is computed theoretically for this tapped delay line channel model and is compared to the results of high fidelity simulations of actual DLLs. A surprising result is obtained. The performance of the DLL depends strongly on the number of taps per chip. As this number increases the DLL delay approaches the theoretical limit.

Veneer recovery from peeler-grade Douglas-fir logs in western Washington.

Treesearch

E.H. Clarke; A.C. Knauss

1957-01-01

As Douglas-fir plywood production continues to expand, increased demands will be made for all grades of peelable Douglas-fir logs. Thus, it becomes increasingly important to know the veneer-grade recovery expected so that timber and logs can be more accurately appraised.

Biological research by optically pumped far infrared lasers

NASA Astrophysics Data System (ADS)

Zhengyu, Mi

1989-05-01

The FIR breeding for paddy rice, black bean and wheat, the chlorophyll mutation of paddy rice induced by optically pumped FIR laser, etc., are presented. The results of SDS electrophoresis analysis of soluble proteins of Drosophita melanrgaster irradiated by optically pumped FIR laser are described and discussed.

Dwarf mistletoe-infected red fir: growth after release

Treesearch

Robert F. Scharpf

1979-01-01

Release cutting, live crown ratio, diameter-at-breast height, and dwarf mistletoe (Arceuthobium abietinum f. sp. magnificae). acted to affect radial and height growth of red firs (Abies magnifica A. Murr.). Infected and noninfected red firs responded well to release as expressed by increased radial growth: growth...

Growing corkbark fir and subalpine fir for nursery production

USDA-ARS?s Scientific Manuscript database

This bulletin is largely based on research conducted at the University of Idaho during 2000-2009. Corkbark and subalpine fir have desirable characteristics for Christmas tree and landscape use, including soft, fragrant foliage that ranges from dark green to silvery or bluish-green. Depending on seed...

Evolutionary history of two endemic Appalachian conifers revealed using microsatellite markers

Treesearch

Kevin M. Potter; John Frampton; Sedley A. Josserand; C. Dana Nelson

2010-01-01

Fraser fir (Abies fraseri [Pursh] Poir.) and intermediate fir (Abies balsamea [L.] Mill. var. phanerolepis Fern.) exist in small populations in the Appalachian highlands of the southeastern United States. We used ten nuclear microsatellite markers to quantify genetic variation within Fraser fir and intermediate...

77 FR 2930 - Airworthiness Directives; Turbomeca S.A. Turboshaft Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-20

... certain power turbine (PT) blade fir-tree roots. This proposed AD would require removing the affected PT... detected geometric non-conformities on blade fir-tree roots. The technical investigations carried out by... was prompted by the detection of geometric non- conformities on PT blade fir-tree roots. We are...

Dwarf Mistletoe on Red Fir . . . infection and control in understory stands

Treesearch

Robert F. Scharpf

1969-01-01

Height and age of understory red fir (Abies magnifica A. Murr.) were related to dwarf mistletoe (Arceuthobiilm campylopodum f. abietinum) infection from the surrounding overstory red fir on four National Forests in California. Percentage of trees infected and intensity of infection increased significantly as height of understory...

Fraser fir stand structure in the Black Mountains of North Carolina

Treesearch

Rachael H. McManamay; Lynn M. Resle; James B. Campbell

2010-01-01

Over the past several decades, naturally occurring populations of Fraser fir (Abies fraseri [Pursh.] Poir) have experienced devastating mortality rates due to attack by the exotic insect, balsam woolly adelgid (BWA) (Adelges piceae Ratz.). The decline in Fraser fir is particularly concerning because its natural geographic...

Belowground competition from overstory trees influences Douglas-fir sapling morphology in thinned stands

Treesearch

Warren D. Devine; Timothy B. Harrington

2009-01-01

We evaluated effects of belowground competition on morphology of naturally established coast Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) saplings in 60- to 80-year-old thinned Douglas-fir stands in southwestern Washington. We separately quantified belowground competition from overstory and understory sources...

AmeriFlux CA-Cha New Brunswick - Charlie Lake site 01 (immature balsam fir forest to be thinned in year 3)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bourque, Charles

This is the AmeriFlux version of the carbon flux data for the site CA-Cha New Brunswick - Charlie Lake site 01 (immature balsam fir forest to be thinned in year 3). Site Description - mature balsam fir forest

Jet Drying of Southern Pine and Douglas-Fir: Exploratory Study

Treesearch

Howard N. Rosen

1978-01-01

Southern pine and Douglas-fir boards, containing both heart- and sapwood and 1.75 inches thick, were jet dried at temperatures from 160 to 400 F and air velocities from 3,000 to 9,000 fmp. Jet drying was more effective for southern pine than for Douglas-fir.

A forest health inventory assessment of red fir (Abies magnifica) in upper montane California

Treesearch

Leif Mortenson; Andrew N. Gray; David C. Shaw

2015-01-01

We investigated the forest health of red fir (Abies magnifica) and how it compared with commonly-associated species Jeffrey pine (Pinus jeffreyi), lodgepole pine (Pinus contorta) and white fir (Abies concolor) in the upper montane forests of California. We evaluated tree mortality rates...

Response of different white fir geographic provenances to Trichosporium symbioticum inoculation in California

Treesearch

William J. Otrosina; Stanley J. Zarnoch

2012-01-01

We inoculated the fir engraver (Scolytus ventralis LeConte) associated fungus Trichosporium symbioticum Wright onto 56 white fir (Abies concolor (Gordon & Glend.) Lindl. ex Hildebr.) trees planted in a common garden study near Camino, California, that represented five geographic provenances of this species....

Saddle Bag Mountain Research Natural Area: guidebook supplement 34.

Treesearch

Reid Schuller; Ronald L. Exeter

2007-01-01

This guidebook describes the Saddle Bag Mountain Research Natural Area, a 121-ha (300-ac) tract established to represent an old-growth remnant of Pacific silver fir (Abies amabilis) and western hemlock (Tsuga heterophylla) forest in the Oregon Coast Range. Pacific silver fir and noble fir (Abies procera)...

Madrone duff and the natural regeneration of Douglas-fir.

Treesearch

Don Minore

1987-01-01

Excellent natural regeneration of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) often occurs under canopies of Pacific madrone (Arbutus menziesii Pursh), but the effects of madrone duff on regeneration are poorly understood. A field experiment was conducted in a thinned Douglas-fir stand in southwestern Oregon to see if...

Dwarfmistletoe of Douglas-fir

Treesearch

Donald P. Graham

1961-01-01

Dwarfmistletoe (Arceuthobium douglasii Engelm.), one of the most destructive enemies of Douglas-fir, causes serious losses in many stands. This parasitic plant is present almost everywhere within the range of Douglas-fir in the northern, central, and southern Rockies. It is abundant in eastern Washington and Oregon and is common in southwestern Oregon and northern...

Truffle abundance and mycophagy by northern flying squirrels in eastern Washington forests.

Treesearch

John F. Lehmkuhl; Laura E. Gould; Efren Cazares; David R. Hosford

2004-01-01

Although much is known about truffle abundance and rodent mycophagy in mesic Douglas-fir forests in the Pacific Northwest, few data are available for dry interior montane forests dominated by ponderosa pine (Pinus ponderosa), Douglas-fir (Pseudotsuga menziesii), and grand fir (Abies grandis). Our objective...

Douglas-fir displays a range of growth responses to temperature, water, and Swiss needle cast in western Oregon, USA

EPA Science Inventory

Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) growth in the Pacific Northwest is affected by climatic, edaphic factors and Swiss needle cast (SNC) disease. We examine Douglas-fir growth responses to temperature, dewpoint deficit (DPD), soil moisture, and SNC ...

Graft union formation in Douglas-fir.

Treesearch

D.L. Copes

1969-01-01

Greenhouse-grown Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) graft unions were examined between 2 and 84 days after grafting. Room temperature was maintained at 60-70 F throughout the growing season. In most respects grafts of Douglas-fir followed development patterns previously reported for spruce and pine grafts, but specific differences...

Design and analysis of optically pumped submillimeter waveguide maser amplifiers and oscillators

NASA Technical Reports Server (NTRS)

Galantowicz, T. A.

1975-01-01

The design and experimental measurements are described of an optically pumped far-infrared (FIR) waveguide maser; preliminary measurements on a FIR waveguide amplifier are presented. The FIR maser was found to operate satisfactorily in a chopped CW mode using either methanol (CH3OH) or acetonitrile (CH3CN) as the active molecule. Two other gases, difluoroethane and difluoroethylene, produced an unstable output with high threshold and low output power when operated in the chopped CW mode. Experimental measurements include FIR output versus cavity length, output beam pattern, output power versus pressure, and input power. The FIR output was the input to an amplifier which was constructed similar to the oscillator. An increase of 10% in output power was noted on the 118.8 microns line of methanol.

Simulations of a FIR Oscillator with Large Slippage parameter at Jefferson Lab for FIR/UV pump-probe experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benson, Stephen V.; Campbell, L. T.; McNeil, B.W.T.

We previously proposed a dual FEL configuration on the UV Demo FEL at Jefferson Lab that would allow simultaneous lasing at FIR and UV wavelengths. The FIR source would be an FEL oscillator with a short wiggler providing diffraction-limited pulses with pulse energy exceeding 50 microJoules, using the exhaust beam from a UVFEL as the input electron beam. Since the UV FEL requires very short pulses, the input to the FIR FEL is extremely short compared to a slippage length and the usual Slowly Varying Envelope Approximation (SVEA) does not apply. We use a non-SVEA code to simulate this systemmore » both with a small energy spread (UV laser off) and with large energy spread (UV laser on).« less

The Dust Content and Opacity of Actively Star-Forming Galaxies

NASA Technical Reports Server (NTRS)

Calzetti, Daniela; Armus, Lee; Bohlin, Ralph C.; Kinney, Anne L.; Koornneef, Jan; Storchi-Bergmann, Thaisa

2000-01-01

We present far-infrared (FIR) photometry at 150 and 205 micron(s) of eight low-redshift starburst galaxies obtained with the Infrared Space Observatory (ISO) ISOPHOT. Five of the eight galaxies are detected in both wave bands, and these data are used, in conjunction with IRAS archival photometry, to model the dust emission at lambda approximately greater than 40 microns. The FIR spectral energy distributions (SEDs) are best fitted by a combination of two modified Planck functions, with T approx. 40 - 55 K (warm dust) and T approx. 20-23 K (cool dust) and with a dust emissivity index epsilon = 2. The cool dust can be a major contributor to the FIR emission of starburst galaxies, representing up to 60% of the total flux. This component is heated not only by the general interstellar radiation field, but also by the starburst itself. The cool dust mass is up to approx. 150 times larger than the warm dust mass, bringing the gas-to-dust ratios of the starbursts in our sample close to Milky Way values, once resealed for the appropriate metallicity. The ratio between the total dust FIR emission in the range 1-1000 microns and the IRAS FIR emission in the range 40 - 120 microns is approx. 1.75, with small variations from galaxy to galaxy. This ratio is about 40% larger than previously inferred from data at millimeter wavelengths. Although the galaxies in our sample are generally classified as "UV bright," for four of them the UV energy emerging shortward of 0.2 microns is less than 15% of the FIR energy. On average, about 30% of the bolometric flux is coming out in the UV-to-near-IR wavelength range; the rest is emitted in the FIR. Energy balance calculations show that the FIR emission predicted by the dust reddening of the UV-to-near-IR stellar emission is within a factor of approx. 2 of the observed value in individual galaxies and within 20% when averaged over a large sample. If our sample of local starbursts is representative of high-redshift (z approx. greater than 1), UV - bright star-forming galaxies, these galaxies' FIR emission will be generally undetected in submillimeter surveys, unless: (1) their bolometric luminosity is comparable to or larger than that of ultraluminous FIR galaxies and (2) their FIR SED contains a cool dust component.

Flexural waves induced by electro-impulse deicing forces

NASA Technical Reports Server (NTRS)

Gien, P. H.

1990-01-01

The generation, reflection and propagation of flexural waves created by electroimpulsive deicing forces are demonstrated both experimentally and analytically in a thin circular plate and a thin semicylindrical shell. Analytical prediction of these waves with finite element models shows good correlation with acceleration and displacement measurements at discrete points on the structures studied. However, sensitivity to spurious flexural waves resulting from the spatial discretization of the structures is shown to be significant. Consideration is also given to composite structures as an extension of these studies.

A Projection of the Characteristics of Group 4 Facsimile Equipment.

DTIC Science & Technology

1981-02-01

et de transfert quasi nu[ pour i compression d’impulsion donnd A cc genre de f <cJ ci! etf fo +Af. fitre ne modiflant pas Ia phase filtre adaptd : Ia...be used on the public telephone network where an DD, 1473k EiTiow or, Nov6 s OBSOLETE SECURITY CLASSIFICATION OF TN;S PAGE (When De E...are not necessarily visible to host computers attached to the network. Datagram: A finite length packet of data together with des - tination host

Ectomycorrhizal fungi associated with ponderosa pine and Douglas-fir: a comparison of species richness in native western North American forests and Patagonian plantations from Argentina.

PubMed

Barroetaveña, C; Cázares, E; Rajchenberg, M

2007-07-01

The putative ectomycorrhizal fungal species registered from sporocarps associated with ponderosa pine and Douglas-fir forests in their natural range distribution (i.e., western Canada, USA, and Mexico) and from plantations in south Argentina and other parts of the world are listed. One hundred and fifty seven taxa are reported for native ponderosa pine forests and 514 taxa for native Douglas-fir forests based on available literature and databases. A small group of genera comprises a high proportion of the species richness for native Douglas-fir (i.e., Cortinarius, Inocybe, and Russula), whereas in native ponderosa pine, the species richness is more evenly distributed among several genera. The comparison between ectomycorrhizal species richness associated with both trees in native forests and in Patagonia (Argentina) shows far fewer species in the latter, with 18 taxa for the ponderosa pine and 15 for the Douglas-fir. Epigeous species richness is clearly dominant in native Douglas-fir, whereas a more balanced relation epigeous/hypogeous richness is observed for native ponderosa pine; a similar trend was observed for Patagonian plantations. Most fungi in Patagonian Douglas-fir plantations have not been recorded in plantations elsewhere, except Suillus lakei and Thelephora terrestris, and only 56% of the fungal taxa recorded in Douglas-fir plantations around the world are known from native forests, the other taxa being new associations for this host, suggesting that new tree + ectomycorrhizal fungal taxa associations are favored in artificial situations as plantations.

Fir Decline and Mortality in the Southern Siberian Mountains

NASA Technical Reports Server (NTRS)

Kharuk, Viacheslav I.; Im, Sergei T.; Petrov, Ilya A.; Dvinskaya, Mariya, L.; Fedotova, Elena V.; Ranson, Kenneth J.

2016-01-01

Increased dieback and mortality of dark needle conifer (DNC) stands (composed of fir (Abies sibirica),Siberian pine (Pinus sibirica) and spruce (Picea obovata)) were documented in Russia during recent decades. Here we analyzed spatial and temporal patterns of fir decline and mortality in the southern Siberian Mountains based on satellite, in situ and dendrochronological data. The studied stands are located within the boundary between DNC taiga to the north and forest-steppe to the south. Fir decline and mortality were observed to originate where topographic features contributed to maximal water-stress risk, i.e., steep (18 deg to 25 deg), convex, south-facing slopes with a shallow well-drained root zone. Fir regeneration survived droughts and increased stem radial growth, while upper canopy trees died. Tree ring width (TRW) growth negatively correlated with vapor pressure deficit (VPD), drought index and occurrence of late frosts, and positively with soil water content. Previous year growth conditions (i.e., drought index, VPD, soil water anomalies) have a high impact on current TRW (r = 0.60 to 0.74). Fir mortality was induced by increased water stress and severe droughts (as a primary factor) in synergy with bark-beetles and fungi attacks (as secondary factors). Dendrochronology data indicated that fir mortality is a periodic process. In a future climate with increased aridity and drought frequency, fir (and Siberian pine) may disappear from portions of its current range (primarily within the boundary with the forest- steppe) and is likely to be replaced by drought-tolerant species such as Pinus sylvestris and Larix sibirica.

RADIO OBSERVATIONS OF THE STAR FORMATION ACTIVITIES IN THE NGC 2024 FIR 4 REGION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Minho; Kang, Miju; Lee, Jeong-Eun, E-mail: minho@kasi.re.kr

Star formation activities in the NGC 2024 FIR 4 region were studied by imaging centimeter continuum sources and water maser sources using several archival data sets from the Very Large Array. The continuum source VLA 9 is elongated in the northwest–southeast direction, consistent with the FIR 4 bipolar outflow axis, and has a flat spectrum in the 6.2–3.6 cm interval. The three water maser spots associated with FIR 4 are also distributed along the outflow axis. One of the spots is located close to VLA 9, and another one is close to an X-ray source. Examinations of the positions ofmore » compact objects in this region suggest that the FIR 4 cloud core contains a single low-mass protostar. VLA 9 is the best indicator of the protostellar position. VLA 9 may be a radio thermal jet driven by this protostar, and it is unlikely that FIR 4 contains a high-mass young stellar object (YSO). A methanol 6.7 GHz maser source is located close to VLA 9, at a distance of about 100 AU. The FIR 4 protostar must be responsible for the methanol maser action, which suggests that methanol class II masers are not necessarily excited by high-mass YSOs. Also discussed are properties of other centimeter continuum sources in the field of view and the water masers associated with FIR 6n. Some of the continuum sources are radio thermal jets, and some are magnetically active young stars.« less

Survey for balsam woolly adegid in Washington and Oregon.

Treesearch

I. Ragenovich; B. Willhite; R. Mitchell; D. Overhulser; K. Ripley

2002-01-01

Balsam woolly adelgid (BWA) is an introduced insect that has had a significant impact on Abies tree species in the Pacific Northwest. During the late 1950s and 1960s, it caused extensive mortality of grand fir (A. grandis), subalpine fir (A. lasiocarpa), and silver fir (A. amabilis), particularly in the...

Relationship between self-fertility, allocation of growth, and inbreeding depression in three coniferous species.

Treesearch

Frank C. Sorensen

1999-01-01

Mortality and growth of self and outcross families of three wind-pollinated, mixed-mating, long-lived conifers, Douglas-fir (Pseudotsuga menziesii), ponderosa pine (Pinus ponderosa), and noble fir (Abies procera) were followed from outplanting to age 26 (25 for noble fir) in spaced plantings at a common...

Pulp quality from small-diameter trees.

Treesearch

G.C. Myers; S. Kumar; R.R. Gustafson; R.J. Barbour; S.M. Abubakr

1997-01-01

Kraft and thermomechanical (TMP) pulps were prepared and evaluated from lodgepole pine and mixed Douglas-fir/western larch sawmill residue chips; lodgepole pine, Douglas-fir, and western larch submerchantable logs; and lodgepole pine, Douglas-fir, and western larch small trees and tops. Kraft pulp from small trees and tops was identical to that from submerchantable...

Population dynamics of dwarf mistletoe on young true firs in the central Sierra Nevada, California

Treesearch

Robert E Scharpf; J. R. Jr. Parmeter

1982-01-01

Young red firs (Abies magnifica A. Murr.) and white firs (A. concolor [Gord. & Glend.] Lindl. ex Hildebr.) on the Stanislaus National Forest, California, were inoculated with seeds of dwarf mistletoe (Arceuthobium abietinum) for 5 successive years. Only 3 to 4 percent of about 7000 seeds placed on branches...

Growth of bear-damaged trees in a mixed plantation of Douglas-fir and red alder.

Treesearch

Richard E. Miller; Harry W. Anderson; Donald L. Reukema; Timothy A. Max

2007-01-01

Incidence and effects of tree damage by black bear (Ursus americanus altifrontalis) in a 50-year-old, coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) plantation are described. Bears girdled or partially girdled 35 dominant or codominant Douglas-fir trees per acre, but only in that...

Forest tree improvement in California-1970

Treesearch

M. Thompson Conkle

1972-01-01

Foresters in California were surveyed in 1970 to determine the extent of artificial regeneration and tree improvement efforts in the State. Seeding of Douglas-fir was the prevailing practice in the North Coast. Inland areas were being planted with conifers, including ponderosa, Jeffrey, Monterey, and sugar pines, Douglas-fir, and red and white firs. Manpower devoted to...

Conversion of SPORL pretreated Douglas fir forest residues into microbial lipids with oleaginous yeasts

USDA-ARS?s Scientific Manuscript database

Douglas fir is the dominant commercial tree grown in the United States. In this study Douglas fir residue was converted to single cell oils using oleaginous yeasts. Monosaccharides were extracted from the woody biomass by pretreating with sulfite and dilute sulfuric acid (SPORL process) and hydrol...

A SNP resource for douglas-fir: de novo transcriptome assembly and SNP detection and validation

Treesearch

Glenn R. Howe; Jianbin Yu; Brian Knaus; Richard Cronn; Scott Kolpak; Peter Dolan; W. Walter Lorenz; Jeffrey F.D. Dean

2013-01-01

Douglas-fir (Pseudotsuga menziesii), one of the most economically and ecologically important tree species in the world, also has one of the largest tree breeding programs. Although the coastal and interior varieties of Douglas-fir (vars. menziesii and glauco) are native to North America, the coastal variety is...

First report of Phytophthora ramorum infecting grand fir in California

Treesearch

K.L. Riley; G.A. Chastagner

2011-01-01

Phytophthora ramorum was detected on grand fir in 2003 and 2005 in a Christmas tree plantation near Los Gatos, CA, in association with infected California bay laurel. Isolates derived from stem lesions were used to inoculate grand fir seedlings in two tests. Isolations from lesions on inoculated plants were positive for P. ramorum...

Climate and growth rate as related to an outbreak of silver fir beetles.

Treesearch

Gerard M. Thomas

1957-01-01

In 1947, an outbreak of silver fir beetles, Pseudohylesinus grandis Sw. and P. granulatus (Lec.), was discovered in northwestern Washington. The epidemic flourished for the next six years, killing some 525 million board-feet of Pacific silver fir, Abies amabilis (Dougl.) Forbes. Prior to 1947, the silver...

Shelterwood regeneration of true fir: conclusion after 8 years

Treesearch

Robert J. Laacke; Jeanne H. Tomascheski

1986-01-01

Shelterwood cuttings on Swain Mountain Experimental Forest were measured to determine performance six to eight years after the shelterwood cutting and before shelterwood removal. Use of appropriate selecting criteria minimized windthrow of seed trees. Regeneration remained red fir, even where the major seed source was white fir. Density of seed trees may affect...

Photo guide for appraising downed woody fuels in Montana forests: Interior ponderosa pine, ponderosa pine - larch - Douglas-fir, larch - Douglas-fir, and interior Douglas-fir cover types

Treesearch

William C. Fischer

1981-01-01

Four series of color photographs show different levels of downed woody material resulting from natural processes in four forest cover types in Montana. Each photo is supplemented by fuel inventory data and potential fire behavior ratings.

Douglas-fir tussock moth: an annotated bibliography.

Treesearch

Robert W. Campbell; Lorna C. Youngs

1978-01-01

This annotated bibliography includes references to 338 papers. Each deals in some way with either the Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), or a related species. Specifically, 210 publications and 82 unpublished documents make some reference, at least, to the Douglas-fir tussock moth; 55 are concerned with other species in...

Survival, frost susceptibility, growth, and disease resistance of corkbark and subalpine fir grown for landscape and Christmas trees

USDA-ARS?s Scientific Manuscript database

Trees from six corkbark fir (Abies lasiocarpa var. arizonica) and 10 subalpine fir (A. lasiocarpa var. lasiocarpa) seed sources were grown at the University of Idaho Sandpoint Research and Extension Center (SREC) and two commercial nurseries in Idaho and Oregon. Post transplant mortality was highest...

Multi-decadal establishment for single-cohort Douglas-fir forests

Treesearch

James A. Freund; Jerry F. Franklin; Andrew J. Larson; James A. Lutz

2014-01-01

The rate at which trees regenerate following stand-replacing wildfire is an important but poorly understood process in the multi-century development of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) forests. Temporal patterns of Douglas-fir establishment reconstructed from old-growth forests (>450 year) have...

Mammoth lakes revisited—50 years after a Douglas-fir tussock moth outbreak.

Treesearch

Boyd E. Wickman; G. Lynn Starr

1990-01-01

For five decades after an outbreak of Douglas-fir tussock moth (Orgyia pseudotsugata (McDunnough)), radial growth of defoliated white fir trees (Abies concolor (Gord. & Glend.) Lindl.), was significantly greater than that of nondefoliated host trees nearby. The increased growth probably was due to the thinning effect of...

TECHNICAL NOTE: Direct finite-element analysis of the frequency response of a Y-Z lithium niobate SAW filter

NASA Astrophysics Data System (ADS)

Xu, Guanshui

2000-12-01

A direct finite-element model is developed for the full-scale analysis of the electromechanical phenomena involved in surface acoustic wave (SAW) devices. The equations of wave propagation in piezoelectric materials are discretized using the Galerkin method, in which an implicit algorithm of the Newmark family with unconditional stability is implemented. The Rayleigh damping coefficients are included in the elements near the boundary to reduce the influence of the reflection of waves. The performance of the model is demonstrated by the analysis of the frequency response of a Y-Z lithium niobate filter with two uniform ports, with emphasis on the influence of the number of electrodes. The frequency response of the filter is obtained through the Fourier transform of the impulse response, which is solved directly from the finite-element simulation. It shows that the finite-element results are in good agreement with the characteristic frequency response of the filter predicted by the simple phase-matching argument. The ability of the method to evaluate the influence of the bulk waves at the high-frequency end of the filter passband and the influence of the number of electrodes on insertion loss is noteworthy. We conclude that the direct finite-element analysis of SAW devices can be used as an effective tool for the design of high-performance SAW devices. Some practical computational challenges of finite-element modeling of SAW devices are discussed.

Analysis of conifer forest regeneration using Landsat Thematic Mapper data

NASA Technical Reports Server (NTRS)

Fiorella, Maria; Ripple, William J.

1995-01-01

Landsat Thematic Mapper (TM) data were used to evaluate young conifer stands in the western Cascade Mountains of Oregon. Regression and correlation analyses were used to describe the relationships between TM band values and age of young Douglas-fir stands (2 to 35 years old). Spectral data from well regenerated Douglas-fir stands were compared to those of poorly regenerated conifer stands. TM bands 1, 2, 3, 5, 6, and 7 were inversely correlated with the age (r greater than or equal to -0.80) of well regenerated Douglas-fir stands. Overall, the 'structural index' (TM 4/5 ratio) had the highest correlation to age of Douglas-fir stands (r = 0.96). Poorly regenerated stands were spectrally distinct from well regenerated Douglas-fir stands after the stands reached an age of approximately 15 years.

Accurate thermometry based on the red and green fluorescence intensity ratio in NaYF₄: Yb, Er nanocrystals for bioapplication.

PubMed

Liu, Lixin; Qin, Feng; Lv, Tianquan; Zhang, Zhiguo; Cao, Wenwu

2016-10-15

A biological temperature measurement method based on the fluorescence intensity ratio (FIR) was developed to reduce uncertainty. The upconversion luminescence of NaYF₄:Yb, Er nanocrystals was studied as a function of temperature around the physiologically relevant range of 300-330 K. We found that the green-green FIR Fe and red-green FIR (I₆₆₀/I₅₄₀) varied linearly as temperature increased. The thermometric uncertainties using the two FIRs were discussed and were determined to be almost constant at 0.6 and 0.09 K for green-green and red-green, respectively. The lower thermometric uncertainty comes from the intense signal-to-noise ratio of the measured FIRs owing to their comparable fluorescence intensities.

Effect of confounding variables on hemodynamic response function estimation using averaging and deconvolution analysis: An event-related NIRS study.

PubMed

Aarabi, Ardalan; Osharina, Victoria; Wallois, Fabrice

2017-07-15

Slow and rapid event-related designs are used in fMRI and functional near-infrared spectroscopy (fNIRS) experiments to temporally characterize the brain hemodynamic response to discrete events. Conventional averaging (CA) and the deconvolution method (DM) are the two techniques commonly used to estimate the Hemodynamic Response Function (HRF) profile in event-related designs. In this study, we conducted a series of simulations using synthetic and real NIRS data to examine the effect of the main confounding factors, including event sequence timing parameters, different types of noise, signal-to-noise ratio (SNR), temporal autocorrelation and temporal filtering on the performance of these techniques in slow and rapid event-related designs. We also compared systematic errors in the estimates of the fitted HRF amplitude, latency and duration for both techniques. We further compared the performance of deconvolution methods based on Finite Impulse Response (FIR) basis functions and gamma basis sets. Our results demonstrate that DM was much less sensitive to confounding factors than CA. Event timing was the main parameter largely affecting the accuracy of CA. In slow event-related designs, deconvolution methods provided similar results to those obtained by CA. In rapid event-related designs, our results showed that DM outperformed CA for all SNR, especially above -5 dB regardless of the event sequence timing and the dynamics of background NIRS activity. Our results also show that periodic low-frequency systemic hemodynamic fluctuations as well as phase-locked noise can markedly obscure hemodynamic evoked responses. Temporal autocorrelation also affected the performance of both techniques by inducing distortions in the time profile of the estimated hemodynamic response with inflated t-statistics, especially at low SNRs. We also found that high-pass temporal filtering could substantially affect the performance of both techniques by removing the low-frequency components of HRF profiles. Our results emphasize the importance of characterization of event timing, background noise and SNR when estimating HRF profiles using CA and DM in event-related designs. Copyright © 2017 Elsevier Inc. All rights reserved.

Herschel/PACS far-IR spectral imaging of a jet from an intermediate mass protostar in the OMC-2 region

NASA Astrophysics Data System (ADS)

González-García, B.; Manoj, P.; Watson, D. M.; Vavrek, R.; Megeath, S. T.; Stutz, A. M.; Osorio, M.; Wyrowski, F.; Fischer, W.; Tobin, J. J.; Sánchez-Portal, M.; Diaz Rodriguez, A. K.; Wilson, T. L.

2016-11-01

We present the first detection of a jet in the far-IR [O I] lines from an intermediate mass protostar. This jet was detected in a Herschel/PACS spectral mapping study in the [O I] lines of OMC-2 FIR 3 and FIR 4, two of the most luminous protostars in Orion outside of the Orion Nebula. The spatial morphology of the fine structure line emission reveals the presence of an extended photodissociation region (PDR) and a narrow, but intense jet connecting the two protostars. The jet seen in [O I] emission is spatially aligned with the Spitzer/IRAC 4.5 μm jet and the CO (6-5) molecular outflow centered on FIR 3. The mass-loss rate derived from the total [O I] 63 μm line luminosity of the jet is 7.7 × 10-6M⊙ yr-1, more than an order of magnitude higher than that measured for typical low-mass class 0 protostars. The implied accretion luminosity is significantly higher than the observed bolometric luminosity of FIR 4, indicating that the [O I] jet is unlikely to be associated with FIR 4. We argue that the peak line emission seen toward FIR 4 originates in the terminal shock produced by the jet driven by FIR 3. The higher mass-loss rate that we find for FIR 3 is consistent with the idea that intermediate-mass protostars drive more powerful jets than their low-mass counterparts. Our results also call into question the nature of FIR 4. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.The final reduced Herschel data used in this paper (FITS) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/596/A26

Added Value of Far-Infrared Radiometry for Ice Cloud Remote Sensing

NASA Astrophysics Data System (ADS)

Libois, Q.; Blanchet, J. P.; Ivanescu, L.; S Pelletier, L.; Laurence, C.

2017-12-01

Several cloud retrieval algorithms based on satellite observations in the infrared have been developed in the last decades. However, most of these observations only cover the midinfrared (MIR, λ < 15 μm) part of the spectrum, and none are available in the far-infrared (FIR, λ ≥ 15 μm). Recent developments in FIR sensors technology, though, now make it possible to consider spaceborne remote sensing in the FIR. Here we show that adding a few FIR channels with realistic radiometric performances to existing spaceborne narrowband radiometers would significantly improve their ability to retrieve ice cloud radiative properties. For clouds encountered in the polar regions and the upper troposphere, where the atmosphere above clouds is sufficiently transparent in the FIR, using FIR channels would reduce by more than 50% the uncertainties on retrieved values of optical thickness, effective particle diameter, and cloud top altitude. This would somehow extend the range of applicability of current infrared retrieval methods to the polar regions and to clouds with large optical thickness, where MIR algorithms perform poorly. The high performance of solar reflection-based algorithms would thus be reached in nighttime conditions. Using FIR observations is a promising venue for studying ice cloud microphysics and precipitation processes, which is highly relevant for cirrus clouds and convective towers, and for investigating the water cycle in the driest regions of the atmosphere.

[Effects of conversion of natural broad-leaved forest to Chinese fir plantation on soil respiration in subtropical China].

PubMed

Zhang, Rui; Bai, Yang; Liu, Juan; Jiang, Pei-kun; Zhou, Guo-mo; Wu, Jia-sen; Tong, Zhi-peng; Li, Yong-fu

2015-10-01

Soil CO2 effluxes in natural broad-leaved forest and the conversed Chinese fir plantation in Linglong Mountains Scenic of Zhejiang Province were evaluated by using static closed chamber and gas chromatography method. The results showed that soil CO2 efflux showed consistent seasonal dynamics in natural broad-leaved forest and Chinese fir plantation, with the maximums observed in summer and autumn, the minimums in winter and spring. Soil CO2 effluxes were 20.0-111.3 and 4.1-118.6 mg C . m-2 . h-1 in natural broad-leaved forest and Chinese fir plantation, respectively. The cumulative soil CO2 emission of natural broad-leaved forest (16.46 t CO2 . hm-2 . a-1) was significantly higher than that of Chinese fir plantation (11.99 t CO2 . hm-2 . a-1). Soil moisture did not affect soil CO2 efflux. There was a significant relationship between soil CO2 efflux and soil temperature at 5 cm depth. There was no significant relationship between soil CO2 efflux of natural broad-leaved forest and water soluble organic carbon content, while water soluble organic carbon content affected significantly soil CO2 efflux in Chinese fir plantation. Converting the natural broad-leaved forest to Chinese fir plantation reduced soil CO2 efflux significantly but improved the sensitivity of soil respiration to environmental factors.

Tree-ring stable isotopes record the impact of a foliar fungal pathogen on CO2 assimilation and growth in Douglas-fir

EPA Science Inventory

Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible...

Documentation of the Douglas-fir tussock moth outbreak-population model.

Treesearch

J.J. Colbert; W. Scott Overton; Curtis. White

1979-01-01

Documentation of three model versions: the Douglas-fir tussock moth population-branch model on (1) daily temporal resolution, (2) instart temporal resolution, and (3) the Douglas-fir tussock moth stand-outbreak model; the hierarchical framework and the conceptual paradigm used are described. The coupling of the model with a normal-stand model is discussed. The modeling...

Host resistance screening for balsam woolly adelgid: A comparison of seedlings from 12 fir species

Treesearch

Leslie Newton; John Frampton; Fred Hain

2012-01-01

The balsam woolly adelgid, Adelges piceae (Hemiptera: Adelgidae) (BWA), first reported on Fraser fir, Abies fraseri (Pursh) Poiret, on Mount Mitchell in 1955 (Amman 1966, Boyce 1955), is a major pest in Christmas tree plantations and in native stands. Nearly all Fraser fir Christmas trees produced in North Carolina...

Development of spruce-fir stands following spruce beetle outbreaks

Treesearch

J. M. Schmid; T. E. Hinds

1974-01-01

Logged and unlogged stands of Engelmann spruce-subalpine fir were evaluated in spruce beetle outbreak areas infested about 15, 25, 50, and 100 years ago. Seedling regeneration was generally adequate except in heavily logged areas, although seedlings were often damaged, apparently by animals. Species composition was dramatically altered in favor of fir in the unlogged...

Guide to understory burning in ponderosa pine-larch-fir forests in the Intermountain West

Treesearch

Bruce M. Kilgore; George A. Curtis

1987-01-01

Summarizes the objectives, prescriptions, and techniques used in prescribed burning beneath the canopy of ponderosa pine stands, and stands of ponderosa pine mixed with western larch, Douglas-fir, and grand fir. Information was derived from 12 districts in two USDA Forest Service Regions and seven National Forests in Montana and Oregon.

Rx for Abies: silvicultural options for diseased firs in Oregon and Washington.

Treesearch

G.M. Filip; C.L. Schmitt

1990-01-01

The true firs are important species in Oregon and Washington forests, but root diseases, stem decays, and dwarf mistletoes cause more mortality, growth loss, and cull in these species than in any other. This paper consolidates research, observations, and management techniques for diseases of true firs, especially the effects of silvicultural activities on root diseases...

Resource use and clonal differences in attack rate by the Douglas-fir seed chalcid, Megastigmus spermotrophus Wachtl (Hymenoptera: Torymidae), in France

Treesearch

Nancy Rappaport; Alain Roques

1991-01-01

The within-cone distribution of Megastigmus spermotrophus Wachtl (Hymenoptera: Torymidae), the Douglas-fir seed chalcid, infesting Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] cones from north-central France was compared with that in samples from California. Results indicate that the mid-region of cones was more intensively...

Decay losses associated with wounds in commercially thinned true fir stands in northern California.

Treesearch

Paul E. Aho; Gary Fiddler; Gregory M. Filip

1989-01-01

A total of 562 white firs (Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.) and red firs (A. magnifica A. Murr.) with logging wounds were felled, dissected, and analyzed for infection and decay in 28 commercially thinned stands on the Klamath and Tahoe National Forests in California. On the Klamath National Forest, decay...

Veneer recovery from Douglas-fir logs.

Treesearch

E.H. Clarke; A.C. Knauss

1957-01-01

During 1956, the Pacific Northwest Forest and Range Experiment Station made a series of six veneer-recovery studies in the Douglas-fir region of Oregon and Washington. The net volume of logs involved totaled approximately 777 M board-feet. Purpose of these studies was to determine volume recovery, by grade of veneer, from the four principal grades of Douglas-fir logs...

Financial analysis of pruning coast Douglas-fir.

Treesearch

Roger D. Fight; James M. Cahlll; Thomas D. Fahey; Thomas A. Snellgrove

1987-01-01

Pruning of coast Douglas-fir was evaluated; recent product recovery information for pruned and unpruned logs for both sawn and peeled products was used. Dimensions of pruned and unpruned trees were simulated with the Douglas-fir stand simulator (DFSIM). Results are presented for a range of sites, ages at time of pruning, ages at time of harvest, product prices, and...

What's in your Douglas-fir bark?

Treesearch

M. Gabriela Buamscha; James E. Altland

2008-01-01

Douglas-fir bark is a common waste product of forest industry, and has potential use as a substrate in container nurseries. Douglas-fir bark (DFB) is strongly acidic and contains amounts of phosphorus, potassium, iron, copper and manganese within or above the levels recommended for growing container crops. As the pH of DFB decreases, electrical conductivity and amounts...

A pioneer exotic tree search for the Douglas-fir region.

Treesearch

Roy R. Silen; Donald L. Olson

1992-01-01

After three-quarters of a century of introduction of 152 conifer and broadleaf species, no promising candidate exotic was found for the Douglas-fir region. Growth curves spanning 50 years or longer are figured for many species. Firs, pines, larches, spruces, hemlocks, and cedars originating in northwestern North America had superior growth rates to those from other...

Behavior of ground vegetation under a partially cut stand of Douglas-fir.

Treesearch

Kenneth W. Krueger

1960-01-01

Environmental changes resulting from logging in the Douglas-fir region often create ideal growing conditions for many woody and herbaceous plants. A rapid increase of brush and low vegetation, in turn, can seriously hinder efforts to establish a new stand. Consequently, one argument against partial cutting in Douglas-fir (Pseudotsuga menziesii) is...

Mortality and growth of dwarf mistletoe-infected red and white fir and the efficacy of thinning for reducing associated losses

Treesearch

H. K. Mehl; S. R. Mori; S. J. Frankel; D. M. Rizzo

2013-01-01

In managed forests dominated by true fir (Abies) species, stands are often restocked using understory trees retained during timber harvest, making the effects of dwarf mistletoe (Arceuthobium spp.) infestation on small true fir a concern. This study examined the response of small red (A. magnifica) and...

Dwarf mistletoe in red and white firs in California–23 to 28 years after inoculation

Treesearch

John R. Parmeter Jr.; Robert F. Scharpf

1989-01-01

Spread and buildup of dwarf mistletoe, Arceuthobium abietinum, was studied on inoculated white fir, Abies concolor, and red fir, A. magnifica, in northern California for 23 to 28 years. At the end of these studies (1986), and in the absence of overstory infection, 13 of 23 trees had dwarf mistletoe populations...

Ecological adaptations in Douglas-fir (Pseudotsuga menziesii var. glauca) populations. III. Central Idaho

Treesearch

Gerald E. Rehfeldt

1983-01-01

Rehfeldt, Gerald E. 1983. Ecological adaptations in Douglas-fir (Pseudotsuga menziesii var. glauca) populations. III. Central Idaho. Canadian Journal of Forest Research. 13: 626-632. Growth, phenology, and cold hardiness of seedlings from 74 populations of Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) from central Idaho were compared in four...

Field performance of stress-laminated highway bridges constructed with glued laminated timber

Treesearch

J.P. Wacker

2004-01-01

This paper summarizes the field performance of three stress-laminated deck timber bridges located in Wisconsin, New York, and Arizona. The deck superstructures of these single-span highway bridges is comprised of full-span glued laminated timber (glulam) beam laminations manufactured with southern pine, hem fir/red maple combination, and/or Douglas fir lumber species....

Growth of white firs defoliated by Modoc budworm in northeastern California

Treesearch

George T. Ferrell

1980-01-01

Open-grown, pole-sized white firs defoliated by Modoc budwonn (Choristoneura viridis) in northeastern California in the years 1959-62 and 1973-75 suffered only minor growth reductions and topkilling compared with the effects that more protracted budworm outbreaks have had elsewhere on their conifer hosts. Growth index analysis indicated that the firs...

A model to estimate noble fir bough weight.

Treesearch

Keith A. Blatner; Roger D. Fight; Nan Vance; Mark Savage; Roger. Chapman

2005-01-01

The harvesting of noble fir (Abies procera) for the production of Christmas wreaths and related products has been a mainstay of the nontimber forest products industry in the Pacific Northwest (PNW) for decades. Although noble fir is the single most important bough product harvested in the PNW, little or no work has been published concerning the...

EXPLAINING THE [C II]157.7 {mu}m DEFICIT IN LUMINOUS INFRARED GALAXIES-FIRST RESULTS FROM A HERSCHEL/PACS STUDY OF THE GOALS SAMPLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diaz-Santos, T.; Armus, L.; Howell, J. H.

We present the first results of a survey of the [C II]157.7 {mu}m emission line in 241 luminous infrared galaxies (LIRGs) comprising the Great Observatories All-sky LIRG Survey (GOALS) sample, obtained with the PACS instrument on board the Herschel Space Observatory. The [C II] luminosities, L{sub [C{sub II]}}, of the LIRGs in GOALS range from {approx}10{sup 7} to 2 Multiplication-Sign 10{sup 9} L{sub Sun }. We find that LIRGs show a tight correlation of [C II]/FIR with far-IR (FIR) flux density ratios, with a strong negative trend spanning from {approx}10{sup -2} to 10{sup -4}, as the average temperature of dustmore » increases. We find correlations between the [C II]/FIR ratio and the strength of the 9.7 {mu}m silicate absorption feature as well as with the luminosity surface density of the mid-IR emitting region ({Sigma}{sub MIR}), suggesting that warmer, more compact starbursts have substantially smaller [C II]/FIR ratios. Pure star-forming LIRGs have a mean [C II]/FIR {approx} 4 Multiplication-Sign 10{sup -3}, while galaxies with low polycyclic aromatic hydrocarbon (PAH) equivalent widths (EWs), indicative of the presence of active galactic nuclei (AGNs), span the full range in [C II]/FIR. However, we show that even when only pure star-forming galaxies are considered, the [C II]/FIR ratio still drops by an order of magnitude, from 10{sup -2} to 10{sup -3}, with {Sigma}{sub MIR} and {Sigma}{sub IR}, implying that the [C II]157.7 {mu}m luminosity is not a good indicator of the star formation rate (SFR) for most local LIRGs, for it does not scale linearly with the warm dust emission most likely associated to the youngest stars. Moreover, even in LIRGs in which we detect an AGN in the mid-IR, the majority (2/3) of galaxies show [C II]/FIR {>=} 10{sup -3} typical of high 6.2 {mu}m PAH EW sources, suggesting that most AGNs do not contribute significantly to the FIR emission. We provide an empirical relation between the [C II]/FIR and the specific SFR for star-forming LIRGs. Finally, we present predictions for the starburst size based on the observed [C II] and FIR luminosities which should be useful for comparing with results from future surveys of high-redshift galaxies with ALMA and CCAT.« less

Light Microscopy Module Imaging Tested and Demonstrated

NASA Technical Reports Server (NTRS)

Gati, Frank

2004-01-01

The Fluids Integrated Rack (FIR), a facility-class payload, and the Light Microscopy Module (LMM), a subrack payload, are integrated research facilities that will fly in the U.S. Laboratory module, Destiny, aboard the International Space Station. Both facilities are being engineered, designed, and developed at the NASA Glenn Research Center by Northrop Grumman Information Technology. The FIR is a modular, multiuser scientific research facility that is one of two racks that make up the Fluids and Combustion Facility (the other being the Combustion Integrated Rack). The FIR has a large volume dedicated for experimental hardware; easily reconfigurable diagnostics, power, and data systems that allow for unique experiment configurations; and customizable software. The FIR will also provide imagers, light sources, power management and control, command and data handling for facility and experiment hardware, and data processing and storage. The first payload in the FIR will be the LMM. The LMM integrated with the FIR is a remotely controllable, automated, on-orbit microscope subrack facility, with key diagnostic capabilities for meeting science requirements--including video microscopy to observe microscopic phenonema and dynamic interactions, interferometry to make thin-film measurements with nanometer resolution, laser tweezers to manipulate micrometer-sized particles, confocal microscopy to provide enhanced three-dimensional visualization of structures, and spectrophotometry to measure the photonic properties of materials. Vibration disturbances were identified early in the LMM development phase as a high risk for contaminating the science microgravity environment. An integrated FIR-LMM test was conducted in Glenn's Acoustics Test Laboratory to assess mechanical sources of vibration and their impact to microscopic imaging. The primary purpose of the test was to characterize the LMM response at the sample location, the x-y stage within the microscope, to vibration emissions from the FIR and LMM support structures.

Effect of casing yield stress on bomb blast impulse

NASA Astrophysics Data System (ADS)

Hutchinson, M. D.

2012-08-01

An equation to predict blast effects from cased charges was first proposed by U. Fano in 1944 and revised by E.M. Fisher in 1953 [1]. Fisher's revision provides much better matches to available blast impulse data, but still requires empirical parameter adjustments. A new derivation [2], based on the work of R.W. Gurney [3] and G.I. Taylor [4], has resulted in an equation which nearly matches experimental data. This new analytical model is also capable of being extended, through the incorporation of additional physics, such as the effects of early case fracture, finite casing thickness, casing metal strain energy dissipation, explosive gas escape through casing fractures and the comparative dynamics of blast wave and metal fragment impacts. This paper will focus on the choice of relevant case fracture strain criterion, as it will be shown that this allows the explicit inclusion of the dynamic properties of the explosive and casing metal. It will include a review and critique of the most significant earlier work on this topic, contained in a paper by Hoggatt and Recht [5]. Using this extended analytical model, good matches can readily be made to available free-field blast impulse data, without any empirical adjustments being needed. Further work will be required to apply this model to aluminised and other highly oxygen-deficient explosives.

Severe leaching of calcium ions from fir needles caused by acid fog.

PubMed

Igawa, Manabu; Kase, Toshiyuki; Satake, Kosuke; Okochi, Hiroshi

2002-01-01

We have measured the components of the throughfall under fir trees (Abies firma) in the field around Mt. Oyama, where the forest appears to be declining, for the period 1994-1998. Exposure experiments of a simulated acid fog to fir twigs were performed under field conditions. There was a similarity between the acid response in the field and that in the laboratory. In both studies, the severe leaching of calcium ions from the needle surface was caused by exposure to acid fog. We also applied acid fog to fir seedlings over 1 year and observed a decrease in the growth of the seedlings due to this application in the dormant season. These results suggest that the severe leaching of calcium ions due to acid fog may cause the deficiency of calcium and be responsible for the decline of the fir trees.

The temporal change in the cortical activations due to salty and sweet tastes in humans: fMRI and time-intensity sensory evaluation.

PubMed

Nakamura, Yuko; Goto, Tazuko K; Tokumori, Kenji; Yoshiura, Takashi; Kobayashi, Koji; Nakamura, Yasuhiko; Honda, Hiroshi; Ninomiya, Yuzo; Yoshiura, Kazunori

2012-04-18

It remains unclear how the cerebral cortex of humans perceives taste temporally, and whether or not such objective data about the brain show a correlation with the current widely used conventional methods of taste-intensity sensory evaluation. The aim of this study was to investigate the difference in the time-intensity profile between salty and sweet tastes in the human brain. The time-intensity profiles of functional MRI (fMRI) data of the human taste cortex were analyzed using finite impulse response analysis for a direct interpretation in terms of the peristimulus time signal. Also, time-intensity sensory evaluations for tastes were performed under the same condition as fMRI to confirm the reliability of the temporal profile in the fMRI data. The time-intensity profile for the brain activations due to a salty taste changed more rapidly than those due to a sweet taste in the human brain cortex and was also similar to the time-intensity sensory evaluation, confirming the reliability of the temporal profile of the fMRI data. In conclusion, the time-intensity profile using finite impulse response analysis for fMRI data showed that there was a temporal difference in the neural responses between salty and sweet tastes over a given period of time. This indicates that there might be taste-specific temporal profiles of activations in the human brain.

Coarse woody debris in a Southern Appalachian spruce-fir forest of the Great Smoky Mountains National Park

Treesearch

Anita K. Rose; N.S. Nicholas

2008-01-01

Spruce-fir forests in the southern Appalachian Mountains receive high atmospheric nitrogen inputs and have high nitrate levels in soil solution and streamwater. High levels of excess nitrogen have been associated with reduced tree vigor. Additionally, the balsam woolly adelgid (Adelges piceae Ratz.) has killed the majority of endemic Fraser fir [

An examination of the genetic control of Douglas-fir vascular tissue phytochemicals: implications for black bear foraging.

Treesearch

Bruce A. Kimball; G.R. Johnson; Dale L. Nolte; Doreen L. Griffin

1999-01-01

Silvicultural practices can influence black bear (Ursus americanus) foraging preferences for Douglas-fir (Pseudotsuga menziesii) cambial-zone vascular tissues, but little is known about the role of genetics. To study the impact of genetic selection, vascular tissue samples were collected from Douglas-fir trees in six half-sib families from five...

Early survival and height growth of Douglas-fir and lodgepole pine seedlings and variations in site factors following treatment of logging residues.

Treesearch

W. Lopushlnsky; D. Zabowskl; T.D. Anderson

1992-01-01

Logging residues were broadcast burned, piled and burned, removed, or left in place after clearcutting in a high-elevation subalpine fir (Abies lasiocarpa (Hook.) Nutt.) lodgepole pine (Pinus contorta Dougl. ex Loud.) forest in north-central Washington. Survival, height growth and foliar nutrient content of planted Douglas-fir...

Assessing the effects of vegetation types on carbon storage fifteen years after reforestation on a Chinese fir site

Treesearch

Qinkui Wang; Silong Wang; Jianwei Zhang

2009-01-01

Forest ecosystems play a significant role in sequestering carbon (C) in biomass and soils. Plantations established in subtropical China since the 1980s, mainly of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) in monocultures, have proved to be major C sinks. However, information is lacking about whether mixing Chinese fir with broadleaved tree...

Conifer-Ceanothus interactions influence tree growth before and after shrub removal in a forest plantation in the western Cascade Mountains, USA.

Treesearch

Heather E. Erickson; Constance A. Harrington

2006-01-01

Ceanothus velutinous is often considered to be an aggressive competitor with young conifers in the western United States. Using a conifer (noble fir, Pacific silver fir, Douglas-fir, and western hemlock) plantation in western WA where Ceanothus had become established, we assessed how conifer-shrub crown interactions affected...

Probability of infestation and extent of mortality associated with the Douglas-fir beetle in the Colorado Front Range

Treesearch

Jose F. Negron

1998-01-01

Infested and uninfested areas within Douglas fir, Pseudotsuga menziesii Mirb.. Franco, stands affected by the Douglas-fir beetle, Dendroctonus pseudotsugae Hopk. were sampled in the Colorado Front Range, CO. Classification tree models were built to predict probabilities of infestation. Regression trees and linear regression analysis were used to model amount of tree...

How to identify brooms in Douglas-fir caused by dwarf mistletoe.

Treesearch

Robert O. Tinnin; Donald M. Knutson

1985-01-01

Dwarf mistletoe causes obvious brooms in Douglas-fir. The brooms are the easiest means of recognizing the presence of dwarf mistletoe; however, dwarf mistletoe is not the only cause of brooming in Douglas-fir. Therefore, accurate identification of dwarf mistletoe brooms is important. If no evidence of aerial shoots can be found in the brooms, and if the brooms occur...

Within-stand spatial distribution of tree mortality caused by the Douglas-Fir beetle (Coleoptera: Scolytidae)

Treesearch

Jose F. Negron; John A. Anhold; A. Steve Munson

2001-01-01

The Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, causes considerable mortality in Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, forests. Within-stand distribution of mortality was examined in affected stands using geostatistical techniques. A 10 x 10 m grid was established in two 4-ha study sites. Live and beetle-killed host basal area was measured at...

A ponderosa pine-grand fir spacing study in central Oregon: results after 10 years.

Treesearch

K.W. Seidel

1985-01-01

The 10-year growth response from an initial spacing study established in a ponderosa pine (Pinus ponderosa Dougl, ex Laws.) and grand fir (Abies grandis (Dougl. ex D. Don) Lindl.) plantation was measured in central Oregon. The study was designed to compare the growth rates of pure pine, pure fir, and a 50-percent mixture of...

Seedfall and seed viability within artificial canopy gaps in a western Washington douglas-fir forest

Treesearch

Warren D. Devine; Timothy B. Harrington

2015-01-01

Seedfall of coast Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) has been studied at the forest edge-clearcut interface and in small canopy gaps, but it has not been evaluated in gap sizes that would be typical of a group-selection method of regeneration. In a mature Douglas-fir forest in the Puget Sound...

Site index curves for white fir in the southwestern United States developed using a guide curve method

Treesearch

Robert L. Mathiasen; William K. Olsen; Carleton B. Edminster

2006-01-01

Site index curves for white fir (Abies concolor) in Arizona, New Mexico, and southwestern Colorado were developed using height-age measurements and an estimated guide curve and 95% confidence intervals for individual predictions. The curves were developed using height-age data for 1,048 white firs from 263 study sites distributed across eight...

White fur lumber recovery at a western Washington sawmill.

Treesearch

E.E. Matson

1957-01-01

In April 1956 a study was made in western Washington to determine grades of lumber that could be expected from silver fir (Abies amabilis) and grand fir (Abies grandis) which are grouped together the lumber industry and sold as white fir. At the sawmill where the study was made, none of the lumber is seasoned and most of it is...

True fir spacing and yield trials—20-year update

Treesearch

Robert O. Curtis

2013-01-01

This report updates data and comparisons from previous reports (Curtis and others 2000, Curtis 2008) on a series of precommercial thinning and yield trials in high-elevation true fir–hemlock stands, using data from the 12 replicates for which 20-year data are now available. The stands were varying mixtures of Pacific silver fir (Abies amabilis (Douglas ex Loudon)...

Natural regeneration of Douglas-fir and associated species using modified clear-cutting systems in the Oregon Cascades.

Treesearch

Jerry F. Franklin

1963-01-01

Clear cutting is the standard harvesting system in old-growth Douglas-fir (Pseudotsuga menziesii) forests in the Pacific Northwest. Usually these clear cuts are in "staggered settings" of 15 to 80 acres with the surrounding stand left uncut to provide seed and serve as a firebreak. However, satisfactory natural regeneration of Douglas-fir...

Flight periodicity of the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (Coleoptera: Curculionidae: Scolytinae) in Colorado, U.S.A

Treesearch

Jose F. Negron; Willis C. Schaupp; Lee Pederson

2011-01-01

There are about 500 species of bark beetles (Coleoptera: Curculionidae: Scolytinae) in the United States (Wood 1982). A number of them are important disturbance agents in forested ecosystems, occasionally creating large tracts of dead trees. One eruptive species is the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, which utilizes Douglas-fir, Pseudotsuga...

Thinning balsam fir thickets with soil sterilants

Treesearch

Arthur C. Hart

1961-01-01

Under certain conditions that we do not yet fully understand, balsam fir has a tendency to form dense thickets that cause stagnation of growth. This condition is common throughout the spruce-fir region, and it presents the landowner with one of his most perplexing management problems. A typical thicket averaging 15 feet tall may contain 5,000 to 10,000 stems per acre (...

Selected yield tables for plantations and natural stands in Inland Northwest Forests

Treesearch

Albert R. Stage; David L. Renner; Roger C. Chapman

1988-01-01

Yields arrayed by site index and age have been tabulated for plantations of 500 trees per acre, with five thinning regimes, for Douglas-fir, grand fir, and western larch. Yields were also tabulated for naturally regenerated stands of the grand fir-cedar-hemlock ecosystem of the Inland Empire. All yields were estimated with the Prognosis Model for Stand Development,...

Changes in wood product proportions in the Douglas-fir region with respect to size, age, and time.

Treesearch

R.A. Monserud; X. Zhou

2007-01-01

We examine both the variation and the changing proportions of different wood products obtained from trees and logs in the Douglas-fir region of the Northwestern United States. Analyses are based on a large product recovery database covering over 40 years of recovery studies; 13 studies are available for Douglas-fir (Pseudotsuga menziesii (Mirb.)...

Five-year field trials using preservative-treated, second-growth Douglas-fir exposed in ground contact in Australia

Treesearch

Rodney C. De Groot; Douglas M. Crawford; Jack Norton; John Keith

2000-01-01

The durability of preservative-treated stakes of second-growth Coastal Douglas-fir was evaluated in a field plot in northern Queensland, Australia. Results from this field trial indicate that second-growth Douglas-fir can be treated with preservatives to meet Australian standards and will provide long-term durability in adverse environments. Data presented indicate...

Height growth and site index curves for Douglas-fir on dry sites in the Willamette National Forest.

Treesearch

Joseph E Means; Mary E. Helm

1985-01-01

Equations and curves are presented for estimating height and site index of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) on hot, dry sites in the Willamette National Forest in western Oregon. The equations are based on the dissected stems of 27 trees. The curves differ from those previously published for Douglas-fir. Instructions are presented...

Annosus Root Disease in True Firs in Northern and Central California National Forests

Treesearch

G. W. Slaughter; J. R. Parmeter Jr.

1989-01-01

True fir stands in California (3.5 million acres) were surveyed during 1979-1980 to estimate the prevalence of infection by Heterobasidion annosum, and to determine stand and tree characteristics associated with the occurrence of annosus root disease. Approximately 4 percent (1.46 billion board-feet) of the live true firs were estimated to be...

Stand development 18 years after gap creation in a uniform Douglas-fir plantation

Treesearch

Robert O. Curtis; Constance A. Harrington; Leslie C. Brodie

2017-01-01

This report gives early results, 18 years after treatment and 30 years after planting, from a trial of early thinning and gap creation intended to increase biodiversity in a very uniform extensive Douglas-fir plantation. Gap creation has introduced canopy irregularity and a substantial hemlock component into what was originally a very uniform pure Douglas-fir...

The distribution of genets and their nuclear composition reveal the dynamics of establishment and survival of Heterobasidion annosum in white fir stands

Treesearch

M. Garbelotto; F.W. Cobb; T.D. Bruns; W. Otrosina; T. Popenuck; Garey Slaughter

1998-01-01

The structure of Heterobasidiom annosum populations in white fir was studied in 15 mixed conifer sites of central and northern California. Areas selected for the study displayed mortality of white fir trees in enlarging discrete patches (mortality centers). At each site, fungal genotypes were defined by somatic compatibility tests...

Fir sawyer beetle-Siberian fir interaction modeling: resistance of fir stands to insect outbreaks

Treesearch

Tamara M. Ovtchinnikova; Victor V. Kiselev

1991-01-01

Entomological monitoring is part of a total ecological monitoring system. Its purpose is the identification, prognosis, and estimation of forest ecosystem impacts induced by insects. The entomological monitoring of a forest is based on a clear understanding of the role played by insects in forest ecosystems. The patterns of insect population dynamics in space and time...

FIR digital filter-based ZCDPLL for carrier recovery

NASA Astrophysics Data System (ADS)

Nasir, Qassim

2016-04-01

The objective of this work is to analyse the performance of the newly proposed two-tap FIR digital filter-based first-order zero-crossing digital phase-locked loop (ZCDPLL) in the absence or presence of additive white Gaussian noise (AWGN). The introduction of the two-tap FIR digital filter widens the lock range of a ZCDPLL and improves the loop's operation in the presence of AWGN. The FIR digital filter tap coefficients affect the loop convergence behaviour and appropriate selection of those gains should be taken into consideration. The new proposed loop has wider locking range and faster acquisition time and reduces the phase error variations in the presence of noise.

Source identification of western Oregon Douglas-fir wood cores using mass spectrometry and random forest classification.

PubMed

Finch, Kristen; Espinoza, Edgard; Jones, F Andrew; Cronn, Richard

2017-05-01

We investigated whether wood metabolite profiles from direct analysis in real time (time-of-flight) mass spectrometry (DART-TOFMS) could be used to determine the geographic origin of Douglas-fir wood cores originating from two regions in western Oregon, USA. Three annual ring mass spectra were obtained from 188 adult Douglas-fir trees, and these were analyzed using random forest models to determine whether samples could be classified to geographic origin, growth year, or growth year and geographic origin. Specific wood molecules that contributed to geographic discrimination were identified. Douglas-fir mass spectra could be differentiated into two geographic classes with an accuracy between 70% and 76%. Classification models could not accurately classify sample mass spectra based on growth year. Thirty-two molecules were identified as key for classifying western Oregon Douglas-fir wood cores to geographic origin. DART-TOFMS is capable of detecting minute but regionally informative differences in wood molecules over a small geographic scale, and these differences made it possible to predict the geographic origin of Douglas-fir wood with moderate accuracy. Studies involving DART-TOFMS, alone and in combination with other technologies, will be relevant for identifying the geographic origin of illegally harvested wood.

FIR statistics of paired galaxies

NASA Technical Reports Server (NTRS)

Sulentic, Jack W.

1990-01-01

Much progress has been made in understanding the effects of interaction on galaxies (see reviews in this volume by Heckman and Kennicutt). Evidence for enhanced emission from galaxies in pairs first emerged in the radio (Sulentic 1976) and optical (Larson and Tinsley 1978) domains. Results in the far infrared (FIR) lagged behind until the advent of the Infrared Astronomy Satellite (IRAS). The last five years have seen numerous FIR studies of optical and IR selected samples of interacting galaxies (e.g., Cutri and McAlary 1985; Joseph and Wright 1985; Kennicutt et al. 1987; Haynes and Herter 1988). Despite all of this work, there are still contradictory ideas about the level and, even, the reality of an FIR enhancement in interacting galaxies. Much of the confusion originates in differences between the galaxy samples that were studied (i.e., optical morphology and redshift coverage). Here, the authors report on a study of the FIR detection properties for a large sample of interacting galaxies and a matching control sample. They focus on the distance independent detection fraction (DF) statistics of the sample. The results prove useful in interpreting the previously published work. A clarification of the phenomenology provides valuable clues about the physics of the FIR enhancement in galaxies.

Blasim: A computational tool to assess ice impact damage on engine blades

NASA Astrophysics Data System (ADS)

Reddy, E. S.; Abumeri, G. H.; Chamis, C. C.

1993-04-01

A portable computer called BLASIM was developed at NASA LeRC to assess ice impact damage on aircraft engine blades. In addition to ice impact analyses, the code also contains static, dynamic, resonance margin, and supersonic flutter analysis capabilities. Solid, hollow, superhybrid, and composite blades are supported. An optional preprocessor (input generator) was also developed to interactively generate input for BLASIM. The blade geometry can be defined using a series of airfoils at discrete input stations or by a finite element grid. The code employs a coarse, fixed finite element mesh containing triangular plate finite elements to minimize program execution time. Ice piece is modeled using an equivalent spherical objective that has a high velocity opposite that of the aircraft and parallel to the engine axis. For local impact damage assessment, the impact load is considered as a distributed force acting over a region around the impact point. The average radial strain of the finite elements along the leading edge is used as a measure of the local damage. To estimate damage at the blade root, the impact is treated as an impulse and a combined stress failure criteria is employed. Parametric studies of local and root ice impact damage, and post-impact dynamics are discussed for solid and composite blades.

Six-year growth of Douglas-fir saplings after manual or herbicide release from coastal shrub competition.

Treesearch

William I. Stein

1999-01-01

Survival and growth of planted Douglas-fir (Pseudotsuga menziesii) saplings and associated shrubs were observed for 6 years after seven release treatments had been applied, side by, side on four areas in the Coast Range of Oregon. Four times as much Douglas-fir volume as in the control was produced by one manual cutting of shrubs, which also...

Seedling Responses of Five Species of Western Conifers to Simulated Ambient Sulfur Dioxide Exposures

Treesearch

Theodor D. Leininger; Paul R. Miller; Susan L. Schilling; Paul H. Dunn

1991-01-01

Seedlings of ponderosa pine, Douglas-fir, white fir, Engelmann spruce, and subalpine fir were exposed continuously to charcoal-filtered (CF) air or one of three levels of a simulated ambient exposure typical of SO, pollution near smelters in the western United States. Seedlings were exposed during winter-spring experiments for 60 days to hourly means of 17, 38, and 54...

Foliage Consumption by 6th-Instar Spruce Budworm Larvae, Choristoneura fumiferana (Clem.) Feeding on Balsam Fir and White Spruce

Treesearch

A.W.  Thomas

1983-01-01

Female larvae ate about 1.5 times as much foliage as male larvae. Larvae ate significantly less old foliage than current foliage. Balsam fir current foliage was eaten in greater quantitities than any other foliage; white spruce current and balsam fir old were eaten to the same extent; very little old white spruce was eaten.

Stereo photo series for quantifying forest residues in the Douglas-Fir-Hemlock type of the Willamette National Forest.

Treesearch

Roger D. Ottmar; Colin C. Hardy; Robert E. Vihnanek

1990-01-01

A series of stereo photographs displays a range of residue loadings for harvested units in the Douglas-fir-western hemlock cover type common to the Willamette National Forest. Postburn residue levels are also represented for the Douglas-fir-western hemlock types. Information with each photo includes measured quadratic means and weights for various size classes, woody...

White fir stands killed by tussock moth...70-mm. color photography aids detection

Treesearch

Steven L. Wert; Boyd E. Wickman

1968-01-01

The use of large-scale 70 mm. aerial photography proved to be an effective technique for detecting trees in white fir stands killed by Douglas-fir tussock moth in northeastern California. Correlations between ground and photo estimates of dead trees were high. But correlations between such estimates of lesser degrees of tree damage--thin tops and topkill--were much...

Genetic diversity and seed production in Santa Lucia fir (Abies bracteata),a relict of the Miocene broadleaved evergreen forest

Treesearch

F. Thomas Ledig; Paul D. Hodgskiss; David R. Johnson

2006-01-01

Santa Lucia fir (Abies bracteata), is a unique fir, the sole member of the subgenus Pseudotorreya. It is a relict of the Miocene broadleaved evergreen sclerophyll forest, and is now restricted to a highly fragmented range in the Santa Lucia Mountains of central coastal California. Expected heterozygosity for 30 isozyme loci in 18 enzyme systems...

Optimal uneven-aged stocking guides: an application to spruce-fir stands in New England

Treesearch

Jeffrey H. Gove; Mark J. Ducey

2014-01-01

Management guides for uneven-aged forest stands periodically need to be revisited and updated based on new information and methods. The current silvicultural guide for uneven-aged spruce-fir management in Maine and the northeast (Frank, R.M. and Bjorkbom, J.C. 1973 A silvicultural guide for spruce-fir in the northeast. General Technical Report NE-6, Forest Service. U.S...

Projected future suitable habitat and productivity of Douglas-fir in western North America

Treesearch

Aaron R. Weiskittel; Nicholas L. Crookston; Gerald E. Rehfeldt

2012-01-01

Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) is one of the most common and commercially important species in western North America. The species can occupy a range of habitats, is long-lived (up to 500 years), and highly productive. However, the future of Douglas-fir in western North America is highly uncertain due to the expected changes in climate conditions....

Effects of soil calcium and aluminum on the physiology of balsam fir and red spruce saplings in northern New England

Treesearch

Richard L. Boyce; Paul G. Schaberg; Gary J. Hawley; Joshua M. Halman; Paula F. Murakami

2013-01-01

We examined the influence of calcium (Ca) and aluminum (Al) nutrition on the foliar physiology of red spruce (Picea rubens Sarg.) and balsam fir [Abies balsamea (L.) Mill.] in northern New England, USA. At the Hubbard Brook Experimental Forest (NH, USA), spruce and fir saplings were sampled from control, Al-, and Ca-supplemented...

The selection system of silviculture in spruce-fir stands - procedures, early results, and comparisons with unmanaged stands

Treesearch

Robert M. Frank; Barton M. Blum

1978-01-01

Early results after 20 years of record keeping indicate that spruce-fir stands will respond to the selection system of silviculture. Stand quality is improved, species composition can be altered, diameter-class distribution approaches a stated goal, stand density is controlled, and yields are increased. Selection silviculture in spruce-fir can now be compared to early...

Conversion of SPORL pretreated Douglas fir forest residues into microbial lipids with oleaginous yeasts

Treesearch

Bruce S. Dien; Junyong Zhu; Patricia J. Slininger; Cletus P. Kurtzman; Bryan R. Moser; Patricia J. O' Bryan; Roland Gleisner; Michael A. Cotta

2016-01-01

Douglas fir is the dominant commercial tree grown in the United States. In this study Douglas fir residue was converted to single cell oils (SCO) using oleaginous yeasts. Monosaccharides were extracted from the woody biomass by pretreating with sulfite and dilute sulfuric acid (SPORL process) and hydrolyzing using commercial cellulases. A new SPORL process that uses pH...

A comparison of postburn woodpecker foraging use of white fir (Abies concolor) and Jeffrey Pine (Pinus jeffreyi)

Treesearch

Kerry L. Farris; Steve Zack

2008-01-01

We examined the temporal patterns of the structural decay, insect infestation and woodpecker foraging patterns on white-fir and yellow pine following a prescribed burn in Lassen National Park, CA. Our objectives were to: 1) describe how pine and fir differ in their decay patterns and insect activity, and 2) determine how these differences reflect woodpecker foraging...

Lumber recovery from young-growth red and white fir in northern California.

Treesearch

W.Y. Pong

1982-01-01

Lumber recovery data from 1,106 logs from 341 young-growth white fir (Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.) and red fir (A. magnifica A. Murr) trees are presented. All logs were processed through a quad-band headsaw. Nominal 2x4's and 2x6's made up over 93 percent of the lumber volume; nearly 70...

Mortality and growth reduction of white fir following defoliation by the Douglas-fir tussock moth

Treesearch

Boyd E. Wickman

1963-01-01

In 5 years after a 1954-56 outbreak of Hemerocampa pseudotsugata in Calaveras and Tuolumne Counties, California, 20 percent of the merchantable white fir, or 11,071 board feet per acre, died in heavily defoliated stands. Another 1,113 board feet per acre was lost owing to radial growth reductions in partly defoliated trees; 12 percent of these trees...

Dimension lumber grades from white fir in Lakeview area.

Treesearch

E.E. Matson

1955-01-01

Production of white fir lumber in the western pine region amounted to a little more than a billion board feet in 1954, or about 13 percent of the output of pine-region sawmills. Moreover, production of the white fir lumber is expanding, and it is important to know what grades of lumber can be expected so that timber and log values can be more accurately appraised....

Released advance reproduction of white and red fir. . . growth, damage, mortality

Treesearch

Donald T. Gordon

1973-01-01

Advance reproduction of white fir and red fir released by cutting overmature over-story was studied at the Swain Mountain Experimental Forest in northern California, at 6,300 feet elevation. Seedling and sapling height growth before logging was only 0.1-0.2 foot per year. Five years after cutting, seedling and sapling height growth had accelerated to about 0.5 to 0.8...

Height-diameter equations for young-growth red fir in California and southern Oregon

Treesearch

K. Leroy Dolph

1989-01-01

Total tree height of young-growth red fir can be estimated from the relation of total tree height to diameter outside bark at breast height (DOB). Total tree heights and corresponding diameters were obtained from stem analyses of 562 trees distributed across 56 sampling locations in the true fir forest type of California and Oregon. The resulting equations can predict...

Deterioration of beetle-killed Douglas-fir in Oregon and Washington: a summary of findings to date.

Treesearch

Ernest Wright; K.H. Wright

1954-01-01

In 1952 and 1953 cooperative research was conducted by the Pacific Northwest Forest Experiment Station and the Research Department of Weyerhaeuser Timber Company to obtain information concerning the rate of deterioration of beetle-killed Douglas-fir. The study was prompted by an outbreak of the Douglas-fir beetle that developed in 1951 and has since killed an estimated...

Assessing post-fire Douglas-fir mortality and Douglas-fir beetle attacks in the northern Rocky Mountains

Treesearch

Sharon Hood; Barbara Bentz; Ken Gibson; Kevin Ryan; Gregg DeNitto

2007-01-01

Douglas-fir has life history traits that greatly enhance resistance to injury from fire, thereby increasing post-fire survival rates. Tools for predicting the probability of tree mortality following fire are important components of both pre-fire planning and post-fire management efforts. Using data from mixed-severity wildfire in Montana and Wyoming, Hood and Bentz (...

Release of Oregon white oak from overtopping Douglas-fir: effects on soil water and microclimate.

Treesearch

W.D. Devine; C.A. Harrington

2007-01-01

Many former Oregon white oak woodland and savanna stands in the coastal Pacific Northwest have been invaded and subsequently overtopped by Douglas-fir during the past century. We examined soil water and microclimate conditions near overtopped oak trees and near oak trees that had been released from Douglas-fir. In each of the three study years, volumetric soil water...

Population buildup and vertical spread of dwarf mistletoe on young red and white firs in California

Treesearch

Robert F. Scharpf; John R. Parmeter Jr.

1976-01-01

Rate of population buildup of dwarf mistletoe, Arceuthobium abietinum Engelm. ex Munz., was slow in most small red firs and white firs 12 to 15 years after inoculation with the parasite. Where population buildup did occur, it remained clustered in the lower portions of tree crowns near inoculation sites. Maximum distance of vertical spread was 16...

Douglas-fir ectomycorrhizae in 40- and 400-year-old stands: mycobiont availability to late successional western hemlock.

Treesearch

T. R. Horton; R. Molina; K. Hood

2005-01-01

We investigated ectomycorrhizal (EM) fungi in forest stands containing both early successional Douglas-fir and late successional western hemlock at two points in the typical stand development by identifying EM fungi from roots of Douglas-fir and western hemlock in mixed stands. Tn an early seral stage forest, EM roots of western hemlock seedlings and intermingling 40-...

Gross yield and mortality tables for fully stocked stands of Douglas-fir.

Treesearch

George R. Staebler

1955-01-01

Increasing interest in the practice of intensive forestry has demonstrated the need for gross yield tables for Douglas-fir showing the volume of trees that die as well as volume of live trees. Net yield tables for Douglas-fir, published in 1930, give the live volume in fully stocked stands at different ages on different sites. As in all normal yield tables, no...

Lumber grades from young-growth Douglas-fir.

Treesearch

E.E. Matson

1952-01-01

Young Douglas-fir timber is known to produce much No. 1 Common and Better lumber but, little or no clear lumber. The volume of lumber produced from young-growth timber has become a sizable part of the cut from the Douglas-fir region of Oregon and Washington. No exact figures are available, but it is estimated that more than one-fourth of the lumber produced from this...

Estimating decay in 40- to 90-year-old grand fir stands in the Clearwater region of northern Idaho.

Treesearch

Gregory M. Filip; John W. Schwandt; Susan K. Hagle

1990-01-01

The fir decay equation for Oregon and Washington was used to predict stem decay in 12 grand fir (Abies grandis (Dougl. ex D. Don) Lindl.) stands in the Clearwater region of northern Idaho. These 12 stands represented a range in geographic and stand characteristic variation. All 12 observed decay percentages were within their associated 95-percent...

Pityophthorus orarius Bright (Coleoptera: Scolytidae) in a northern California Douglas-fir seed orchard: effect of clone, tree vigor, and cone crop on rate of attack

Treesearch

Nancy G. Rappaport; David L. Wood

1994-01-01

The geographic range of the Douglas-fir twig beetle, Pityophthorus orarius Bright, was extended beyond the original provenance of southern British Columbia to northern California. A survey of 457 Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] trees in 1985 revealed that those with heavy cone crops were more likely to be...

Detecting changes in tree health and productivity in silver fir-beech forests of Slovenia

Treesearch

N. Torelli; W.C. Shortle; K. Cufar; F. Ferlin; K.T. Smith

1999-01-01

Cambial electrical resistance (CER) was used as an objective measure of vitality of silver fir (Abies alba) in the forests of Slovenia. Trees were rated during the growing season by CER and a subjective crown status index (CSI). Both CER and CSI were inversely correlated to annual ring width increment. Using both CER and CSI, fir were assigned to...

Hydraulic architecture and photosynthetic capacity as constraints on release from suppression in Douglas-fir and western hemlock.

PubMed

Renninger, Heidi J; Meinzer, Frederick C; Gartner, Barbara L

2007-01-01

We compared hydraulic architecture, photosynthesis and growth in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), a shade-intolerant species, and western hemlock (Tsuga heterophylla (Raf.) Sarg.), a shade-tolerant species, to study the temporal pattern of release from suppressive shade. In particular, we sought to determine whether hydraulic architecture or photosynthetic capacity is most important in constraining release. The study was conducted at two sites with mixed stands of 10- to 20-year-old Douglas-fir and western hemlock. At one site, the stand had been thinned allowing release of the understory trees, whereas at the other site, the stand remained unthinned. Douglas-fir had lower height growth (from 1998-2003) and lower relative height growth (height growth from 1998 to 2003/height in 1998) than western hemlock. However, relative height growth of released versus suppressed trees was higher in Douglas-fir (130%) than in western hemlock (65%), indicating that, although absolute height growth was less, Douglas-fir did release from suppression. Release seemed to be constrained initially by a limited photosynthetic capacity in both species. Five years after release, Douglas-fir trees had 14 times the leaf area and 1.5 times the leaf nitrogen concentration (N (area)) of suppressed trees. Needles of released western hemlock trees had about twice the maximum assimilation rate (A (max)) at ambient [CO(2)] as needles of suppressed trees and exhibited no photoinhibition at the highest irradiances. After release, trees increased in leaf area, leaf N concentration and overall photosynthetic capacity. Subsequently, hydraulic architecture appeared to constrain release in Douglas-fir and, to a lesser extent, in western hemlock. Released trees had significantly less negative foliar delta(13)C values than suppressed trees and showed a positive relationship between leaf area:sapwood area ratio (A (L)/A (S)) and delta(13)C, suggesting that trees with more leaf area for a given sapwood area experienced a stomatal limitation on carbon gain. Nonetheless, these changes had no significant effects on leaf specific conductivities of suppressed versus released trees of either species, but leaf specific root conductance was significantly lower in released Douglas-fir.

Asymmetric Shock Wave Generation in a Microwave Rocket Using a Magnetic Field

NASA Astrophysics Data System (ADS)

Takahashi, Masayuki

2017-10-01

A plasma pattern is reproduced by coupling simulations between a particle-in- cell with Monte Carlo collisions model and a finite-difference time-domain simulation for an electromagnetic wave propagation when an external magnetic field is applied to the breakdown volume inside a microwave-rocket nozzle. The propagation speed and energy-absorption rate of the plasma are estimated based on the breakdown simulation, and these are utilized to reproduce shock wave propagation, which provides impulsive thrust for the microwave rocket. The shock wave propagation is numerically reproduced by solving the compressible Euler equation with an energy source of the microwave heating. The shock wave is asymmetrically generated inside the nozzle when the electron cyclotron resonance region has a lateral offset, which generates lateral and angular impulses for postural control of the vehicle. It is possible to develop an integrated device to maintain beaming ight of the microwave rocket, achieving both axial thrust improvement and postural control, by controlling the spatial distribution of the external magnetic field.

Integrated guidance and control for microsatellite real-time automated proximity operations

NASA Astrophysics Data System (ADS)

Chen, Ying; He, Zhen; Zhou, Ding; Yu, Zhenhua; Li, Shunli

2018-07-01

This paper investigates the trajectory planning and control of autonomous spacecraft proximity operations with impulsive dynamics. A new integrated guidance and control scheme is developed to perform automated close-range rendezvous for underactuated microsatellites. To efficiently prevent collision, a modified RRT* trajectory planning algorithm is proposed under this context. Several engineering constraints such as collision avoidance, plume impingement, field of view and control feasibility are considered simultaneously. Then, the feedback controller that employs a turn-burn-turn strategy with a combined impulsive orbital control and finite-time attitude control is designed to ensure the implementation of planned trajectory. Finally, the performance of trajectory planner and controller are evaluated through numerical tests. Simulation results indicate the real-time implementability of the proposed integrated guidance and control scheme with position control error less than 0.5 m and velocity control error less than 0.05 m/s. Consequently, the proposed scheme offers the potential for wide applications, such as on-orbit maintenance, space surveillance and debris removal.

A General Approach to the Geostationary Transfer Orbit Mission Recovery

NASA Technical Reports Server (NTRS)

Faber, Nicolas; Aresini, Andrea; Wauthier, Pascal; Francken, Philippe

2007-01-01

This paper discusses recovery scenarios for geosynchronous satellites injected in a non-nominal orbit due to a launcher underperformance. The theory on minimum-fuel orbital transfers is applied to develop an operational tool capable to design a recovery mission. To obtain promising initial guesses for the recovery three complementary techniques are used: p-optimized impulse function contouring, a numerical impulse function minimization and the solutions to the switching equations. The tool evaluates the feasibility of a recovery with the on-board propellant of the spacecraft and performs the complete mission design. This design takes into account for various mission operational constraints such as e.g., the requirement of multiple finite-duration burns, third-body orbital perturbations, spacecraft attitude constraints and ground station visibility. In a final case study, we analyze the consequences of a premature breakdown of an upper rocket stage engine during injection on a geostationary transfer orbit, as well as the possible recovery solution with the satellite on-board propellant.

Far-infrared observations of the evolved H II region M16

NASA Technical Reports Server (NTRS)

Mcbreen, B.; Fazio, G. G.; Jaffe, D. T.

1982-01-01

The results of far infrared (FIR) observations of the larger H II region M16, associated with the young open star cluster NGC 6611, are discussed. Three FIR sources detected on an extended ridge of FIR emission within the scanned region are described. The observations confirm that M16 is an H II region in a late stage of evolution. The H II region has expanded and is now extremely density bounded, consisting of an extended region of ionized gas and a series of ionization fronts located at the surrounding molecular cloud boundaries nearest to the exciting OB star cluster. The FIR radiation arises from heated dust at these boundaries.

The correlation between far-IR and radio continuum emission from spiral galaxies

NASA Technical Reports Server (NTRS)

Dickey, John M.; Garwood, Robert W.; Helou, George

1987-01-01

A sample of 30 galaxies selected for their intense IRAS flux at 60 and 100 micron using the Arecibo telescope at 21 cm to measure the continuum and HI line luminosities were observed. The centimeter wave continuum correlates very well with the far-infrared flux, with a correlation coefficient as high as that found for other samples, and the same ratio between FIR and radio luminosities. Weaker correlations are seen between the FIR and optical luminosity and between the FIR and radio continuum. There is very little correlation between the FIR and the HI mass deduced from the integral of the 21 cm line. The strength of the radio continuum correlation suggests that there is little contribution to either the radio and FIR from physical processes not affecting both. If they each reflect time integrals of the star formation rate then the time constants must be similar, or the star formation rate must change slowly in these galaxies.

Dynamics of column stability with partial end restraints

NASA Technical Reports Server (NTRS)

Gregory, Peyton B.

1990-01-01

The dynamic behavior of columns with partial end restraints and loads consisting of a dead load and a pulsating load are investigated. The differential equation is solved using a lumped impulse recurrence formula relative to time coupled with a finite difference discretization along the member length. A computer program is written from which the first critical frequencies are found as a function of end stiffness. The case of a pinned ended column compares very well with the exact solution. Also, the natural frequency and buckling load formulas are derived for equal and unequal end restraints.

On the tidal evolution and tails formation of disc galaxies

NASA Astrophysics Data System (ADS)

Alavi, M.; Razmi, H.

2015-11-01

In this paper, we want to study the tidal effect of an external perturber upon a disc galaxy based on the generalization of already used Keplerian potential. The generalization of the simple ideal Keplerian potential includes an orbital centripetal term and an overall finite range controlling correction. Considering the generalized form of the interaction potential, the velocity impulse expressions resulting from tidal forces are computed; then, using typical real values already known from modern observational data, the evolution of the disc including tidal tails formation is graphically investigated.

Early survival and growth of planted Douglas-fir with red alder in four mixed regimes.

Treesearch

Marshall D. Murray; Richard E. Miller

1986-01-01

To quantify between-species interactions, we measured and compared survival and growth of planted Douglas-fir and associated planted and volunteer red alder at a location on the west side of the Cascade Range in Washington. The planted alder were wildlings dug either from a nearby area or from a distant, coastal site and interplanted into a 3-year-old Douglas-fir...

Effects of manganese and manganese-nitrogen applications on growth and nutrition of Douglas-fir seedlings.

Treesearch

M. A. Radwan; John S. Shumway; Dean S. DeBell

1979-01-01

Effects of manganese (Mn) on Douglas-fir grown in soil, with and without urea, and in nutrient solution were investigated. In addition, Mn sorption by forest soils was evaluated. Results show that Douglas-fir does not respond to added Mn and is quite tolerant to high Mn levels. Moreover, Mn sorption by soils is high. It is doubtful that Mn toxicity is of practical...

Balsam fir conservation and red spruce ecosystem restoration initiatives in the West Virginia highlands

Treesearch

Corey A. Bonasso; David W. Saville

2010-01-01

The West Virginia Highlands Conservancy has been working for more than a decade to protect, conserve, and restore the spruce-fir forests in West Virginia. Beginning in the mid 1990s an effort was initiated to conserve balsam fir in West Virginia where it reaches its southern most extent in North America. This work led to further efforts which have focused on the...

Nonlinear equations for predictiing diameter inside bark at breast height for young-growth red fir in California and southern Oregon

Treesearch

K. Leroy Dolph

1989-01-01

Inside bark diameters of young-growth red fir can be estimated from the relationship of inside bark diameter 10 outside bark diameter at breast height. Inside and outside bark diameter were obtained from stem analyses of 562 trees distributed across 56 sampling locations in the true fir forest type of California and southern Oregon. The resulting equation can predict...

Repeated manual release in a young plantation: effect on Douglas-fir seedlings, hardwoods, shrubs, forbs, and grasses.

Treesearch

Philip M. McDonald; Gary O. Fiddler; Henry Harrison

1994-01-01

Douglas-fir seedlings on the Arcata Resource Area, Bureau of Land Management, U.S. Department of the Interior, in central coastal California, were released by chain sawing and grubbing competing vegetation around them at different frequencies (0, 2, and 3 grubbings) over a 5-year period. After 5 years, average Douglas-fir stem diameter (measured at 12 inches above mean...

Five-year growth responses of Douglas-fir, western hemlock, and western redcedar seedlings to manipulated levels of overstory and understory competition.

Treesearch

T.B. Harrington

2006-01-01

Douglas-fir, western hemlock, and western redcedar seedlings were planted in 2001 within clearcuts, shelterwoods, or thinned stands of second-growth Douglas-fir. Understory vegetation was left untreated or removed to provide areas of vegetation control (AVC) of 0, 50, or 100 percent of seedling growing space. Third-year stem volume of seedlings growing in clearcuts...

Fine-structure mapping of the firA gene, a locus involved in the phenotypic expression of rifampin resistance in Escherichia.

PubMed

Lathe, R

1977-09-01

The firA (Ts)200 mutation not only eliminates the resistance to rifampin of certain genetically resistant strains, but, moreover, renders ribonucleic acid synthesis thermolabile. The firA gene has been mapped by P1 tranduction and is located extremely close to the structural gene for deoxyribonucleic acid polymerase III at 4 min on the Escherichia coli linkage map.

Radial growth in grand fir and Douglas-fir related to defoliation by the Douglas-fir tussock moth in the Blue Mountains outbreak.

Treesearch

B.E. Wickman; D.L. Henshaw; S.K. Gollob

1980-01-01

Radial growth reduction related to amount of tree defoliation was studied following a severe tussock moth outbreak. Growth sharply declined the year after defoliation began, and amount of decline was proportional to percent defoliation. Growth recovery began the year after defoliation ceased and radial increment had returned to pre-outbreak levels 5 years after...

Mulching to regenerate a harsh site: effect on Douglas-fir seedlings, forbs, grasses, and ferns

Treesearch

Philip M. McDonald; Gary O. Fiddler; Henry R. Harrison

1994-01-01

Douglas-fir seedlings on the Arcata District, Bureau of Land Management, U.S. Department of the Interior, in central coastal California, were planted in an effort to restore the natural forest to what was then pastureland. Douglas-fir seedlings were released from a complex forb-grass-fern plant community by applying very large (10-ft square) and very small (2-foot...

Comparative drought resistance of five conifers and foliage moisture content as a viability index.

Treesearch

Richard P. Pharis

1966-01-01

Whole plant lethal points of foliage moisture content (FMC) for ponderosa pine, sugar pine, Douglas-fir, grand fir, and incense-cedar were established from foliage tissue of various ages. Exact lethal level depended upon the age of the tissue, but there was a general plateau between the ages 6 and 13 months for sugar pine and Douglas-fir and 3 and 13 months for incense...

Tree shaking machine aids cone collection in a Douglas-fir seed orchard.

Treesearch

Donald L. Copes; William K. Randall

1983-01-01

A boom-type tree shaker was used in a Douglas-fir seed orchard to remove cones from 7- to 9-meter tall grafted Douglas-fir trees. An average of 55 percent of the cones were removed by shaking, while damage inflicted to the upper crown was confined primarily to branch and leader breakage in the top three internodes. Damage to the lower bole, where the shaker head...

[A comparative study on soil fauna in native secondary evergreen broad-leaved forest and Chinese fir plantation forests in subtropics].

PubMed

Yan, Shaokui; Wang, Silong; Hu, Yalin; Gao, Hong; Zhang, Xiuyong

2004-10-01

In this study, we investigated the response of soil animal communities to the replacement of native secondary forest by Chinese fir plantation forest and successive rotation of Chinese fir in subtropics. Three adjacent forest stands, i.e., native secondary evergreen broad-leaved forest stand (control) and Chinese fir plantation stands of first (20 yr) and second (20 yr) rotations were selected for the comparison of soil fauna. All animals were extracted from the floor litter and 0-15 cm soil layer of the stands in Summer, 2003 by using Tullgren method, wet funnel method and hand-sorting method. Compared to two Chinese fir plantation forests, the native secondary evergreen broad-leaved forest had a higher abundance and a higher taxonomic diversity of animals in soil and litter, but there were no significant differences in the biomass and productivity of soil fauna between all study stands. The abundance or diversity did not differ significantly between the first rotation and second rotation stands, too. The results supported that vegetation cover might be one of the main forces driving the development of soil animal communities, and the effect of successive rotation of Chinese fir on the development of soil fauna was a slow-running process.

Source identification of western Oregon Douglas-fir wood cores using mass spectrometry and random forest classification1

PubMed Central

Finch, Kristen; Espinoza, Edgard; Jones, F. Andrew; Cronn, Richard

2017-01-01

Premise of the study: We investigated whether wood metabolite profiles from direct analysis in real time (time-of-flight) mass spectrometry (DART-TOFMS) could be used to determine the geographic origin of Douglas-fir wood cores originating from two regions in western Oregon, USA. Methods: Three annual ring mass spectra were obtained from 188 adult Douglas-fir trees, and these were analyzed using random forest models to determine whether samples could be classified to geographic origin, growth year, or growth year and geographic origin. Specific wood molecules that contributed to geographic discrimination were identified. Results: Douglas-fir mass spectra could be differentiated into two geographic classes with an accuracy between 70% and 76%. Classification models could not accurately classify sample mass spectra based on growth year. Thirty-two molecules were identified as key for classifying western Oregon Douglas-fir wood cores to geographic origin. Discussion: DART-TOFMS is capable of detecting minute but regionally informative differences in wood molecules over a small geographic scale, and these differences made it possible to predict the geographic origin of Douglas-fir wood with moderate accuracy. Studies involving DART-TOFMS, alone and in combination with other technologies, will be relevant for identifying the geographic origin of illegally harvested wood. PMID:28529831

Blind identification of nonlinear models with non-Gaussian inputs

NASA Astrophysics Data System (ADS)

Prakriya, Shankar; Pasupathy, Subbarayan; Hatzinakos, Dimitrios

1995-12-01

Some methods are proposed for the blind identification of finite-order discrete-time nonlinear models with non-Gaussian circular inputs. The nonlinear models consist of two finite memory linear time invariant (LTI) filters separated by a zero-memory nonlinearity (ZMNL) of the polynomial type (the LTI-ZMNL-LTI models). The linear subsystems are allowed to be of non-minimum phase (NMP). The methods base their estimates of the impulse responses on slices of the N plus 1th order polyspectra of the output sequence. It is shown that the identification of LTI-ZMNL systems requires only a 1-D moment or polyspectral slice. The coefficients of the ZMNL are not estimated, and need not be known. The order of the nonlinearity can, in theory, be estimated from the received signal. These methods possess several noise and interference suppression characteristics, and have applications in modeling nonlinearly amplified QAM/QPSK signals in digital satellite and microwave communications.

Non-linear effects in finite amplitude wave propagation through ducts and nozzles

NASA Technical Reports Server (NTRS)

Salikuddin, M.; Brown, W. H.

1986-01-01

In this paper an extensive study of non-linear effects in finite amplitude wave propagation through ducts and nozzles is summarized. Some results from earlier studies are included to illustrate the non-linear effects on the transmission characteristics of duct and nozzle terminations. Investigaiations, both experimental and analytical, were carried out to determine the magnitudes of the effects for high intensity pulse propagation. The results derived from these investigations are presented in this paper. They include the effect of the sound intensity on the acoustic characteristics of duct and nozzle terminations, the extent of the non-linearities in the propagation of high intensity impulsive sound inside the duct and out into free field, the acoustic energy dissipation mechanism at a termination as shown by flow visualizations, and quantitative evaluations by experimental and analytical means of the influence of the intensity of a sound pulse on the dissipation of its acoustic power.

Two Dimensional Finite Element Analysis for the Effect of a Pressure Wave in the Human Brain

NASA Astrophysics Data System (ADS)

Ponce L., Ernesto; Ponce S., Daniel

2008-11-01

Brain injuries in people of all ages is a serious, world-wide health problem, with consequences as varied as attention or memory deficits, difficulties in problem-solving, aggressive social behavior, and neuro degenerative diseases such as Alzheimer's and Parkinson's. Brain injuries can be the result of a direct impact, but also pressure waves and direct impulses. The aim of this work is to develop a predictive method to calculate the stress generated in the human brain by pressure waves such as high power sounds. The finite element method is used, combined with elastic wave theory. The predictions of the generated stress levels are compared with the resistance of the arterioles that pervade the brain. The problem was focused to the Chilean mining where there are some accidents happen by detonations and high sound level. There are not formal medical investigation, however these pressure waves could produce human brain damage.

Soil spore bank communities of ectomycorrhizal fungi in endangered Chinese Douglas-fir forests.

PubMed

Wen, Zhugui; Shi, Liang; Tang, Yangze; Hong, Lizhou; Xue, Jiawang; Xing, Jincheng; Chen, Yahua; Nara, Kazuhide

2018-01-01

Chinese Douglas-fir (Pseudotsuga sinensis) is an endangered Pinaceae species found in several isolated regions of China. Although soil spore banks of ectomycorrhizal (ECM) fungi can play an important role in seedling establishment after disturbance, such as in the well-known North American relative (Pseudotsuga menziesii), we have no information about soil spore bank communities in relict forests of Chinese Douglas-fir. We conducted bioassays of 73 soil samples collected from three Chinese Douglas-fir forests, using North American Douglas-fir as bait seedlings, and identified 19 species of ECM fungi. The observed spore bank communities were significantly different from those found in ECM fungi on the roots of resident trees at the same sites (p = 0.02). The levels of potassium (K), nitrogen (N), organic matter, and the pH of soil were the dominant factors shaping spore bank community structure. A new Rhizopogon species was the most dominant species in the spore banks. Specifically, at a site on Sanqing Mountain, 22 of the 57 surviving bioassay seedlings (representing 21 of the 23 soil samples) were colonized by this species. ECM fungal richness significantly affected the growth of bioassay seedlings (R 2  = 0.20, p = 0.007). Growth was significantly improved in seedlings colonized by Rhizopogon or Meliniomyces species compared with uncolonized seedlings. Considering its specificity to Chinese Douglas-fir, predominance in the soil spore banks, and positive effect on host growth, this new Rhizopogon species could play critical roles in seedling establishment and forest regeneration of endangered Chinese Douglas-fir.

Reproductive potential of balsam fir (Abies balsamea), white spruce (Picea glauca), and black spruce (P. mariana) at the ecotone between mixedwood and coniferous forests in the boreal zone of western Quebec.

PubMed

Messaoud, Yassine; Bergeron, Yves; Asselin, Hugo

2007-05-01

The reproductive potentials of balsam fir and white spruce (co-dominants in mixedwood forests) and black spruce (dominant in coniferous forests) were studied to explain the location of the ecotone between the two forest types in the boreal zone of Quebec. Four sites were selected along a latitudinal gradient crossing the ecotone. Cone crop, number of seeds per cone, percentage filled seeds, and percentage germination were measured for each species. Balsam fir and white spruce cone crops were significantly lower in the coniferous than in the mixedwood forest, while black spruce had greater crop constancy and regularity between both forest types. Mast years were more frequent for black spruce than for balsam fir in both forest types (mast year data not available for white spruce). The number of seeds per cone was more related to cone size than to forest type for all species. Black spruce produced more filled seeds in the coniferous forest than balsam fir or white spruce. The sum of growing degree-days and the maximum temperature of the warmest month (both for the year prior to cone production) significantly affected balsam fir cone production. The climate-related northward decrease in reproductive potential of balsam fir and white spruce could partly explain the position of the northern limit of the mixedwood forest. This could change drastically, however, as the ongoing climate warming might cancel this competitive advantage of black spruce.

Spatial correlations between browsing on balsam fir by white-tailed deer and the nutritional value of neighboring winter forage.

PubMed

Champagne, Emilie; Moore, Ben D; Côté, Steeve D; Tremblay, Jean-Pierre

2018-03-01

Associational effects, that is, the influence of neighboring plants on herbivory suffered by a plant, are an outcome of forage selection. Although forage selection is a hierarchical process, few studies have investigated associational effects at multiple spatial scales. Because the nutritional quality of plants can be spatially structured, it might differently influence associational effects across multiple scales. Our objective was to determine the radius of influence of neighbor density and nutritional quality on balsam fir ( Abies balsamea ) herbivory by white-tailed deer ( Odocoileus virginianus ) in winter. We quantified browsing rates on fir and the density and quality of neighboring trees in a series of 10-year-old cutovers on Anticosti Island (Canada). We used cross-correlations to investigate relationships between browsing rates and the density and nutritional quality of neighboring trees at distances up to 1,000 m. Balsam fir and white spruce ( Picea glauca ) fiber content and dry matter in vitro true digestibility were correlated with fir browsing rate at the finest extra-patch scale (across distance of up to 50 m) and between cutover areas (300-400 m). These correlations suggest associational effects, that is, low nutritional quality of neighbors reduces the likelihood of fir herbivory (associational defense). Our results may indicate associational effects mediated by intraspecific variation in plant quality and suggest that these effects could occur at scales from tens to hundreds of meters. Understanding associational effects could inform strategies for restoration or conservation; for example, planting of fir among existing natural regeneration could be concentrated in areas of low nutritional quality.

Added value of far-infrared radiometry for remote sensing of ice clouds

NASA Astrophysics Data System (ADS)

Libois, Quentin; Blanchet, Jean-Pierre

2017-06-01

Several cloud retrieval algorithms based on satellite observations in the infrared have been developed in the last decades. However, these observations only cover the midinfrared (MIR, λ < 15 μm) part of the spectrum, and none are available in the far-infrared (FIR, λ≥ 15 μm). Using the optimal estimation method, we show that adding a few FIR channels to existing spaceborne radiometers would significantly improve their ability to retrieve ice cloud radiative properties. For clouds encountered in the polar regions and the upper troposphere, where the atmosphere is sufficiently transparent in the FIR, using FIR channels would reduce by more than 50% the uncertainties on retrieved values of optical thickness, effective particle diameter, and cloud top altitude. Notably, this would extend the range of applicability of current retrieval methods to the polar regions and to clouds with large optical thickness, where MIR algorithms perform poorly. The high performance of solar reflection-based algorithms would thus be reached in nighttime conditions. Since the sensitivity of ice cloud thermal emission to effective particle diameter is approximately 5 times larger in the FIR than in the MIR, using FIR observations is a promising venue for studying ice cloud microphysics and precipitation processes. This is highly relevant for cirrus clouds and convective towers. This is also essential to study precipitation in the driest regions of the atmosphere, where strong feedbacks are at play between clouds and water vapor. The deployment in the near future of a FIR spaceborne radiometer is technologically feasible and should be strongly supported.

Syntheses, crystal structures and fluorescent properties of three metal- tris(4‧-carboxybiphenyl)amine frameworks

NASA Astrophysics Data System (ADS)

Yuan, Lv-Bing; He, Yan-Ping; Xu, Hai; Zhang, Jian

2017-11-01

Triphenylamine and its derivatives have been widely concerned because of their excellent performance in the area of the photoelectric functional material. In this work, we chose a nanosized tris(4‧-carboxybiphenyl)amine (H3TPA) as organic ligand. By employing the H3TPA ligand to assemble with M2+ (M = Zn, Cd, and Pb) ions, respectively, three metal-organic frameworks (FIR-43 to FIR-45, FIR denotes Fujian Institute of Research) have been synthesized under different solvent systems. FIR-43 exhibits a 3-connected two-dimensional (2D) network based on mononuclear [Zn(COO)3] second building unit (SBU). Unlike the anionic framework FIR-43, FIR-44 is a neutral 2D layer constructed by trinuclear [Cd3(COO)6] SBU and displays a (3,6)-NbSe2 topology structure. If the weak Pb-O interactions in the range of 2.79-2.88 Å are considered, FIR-45 is a neutral 3D framework built by hexanuclear [Pb6(DMAE)6(COO)6] SBU (DMAE = N,N-dimethylethanolamine) and represents a (3,6)-connected (4·82)2(42·811·102) topology. Thermogravimetric analyses (TGA) and X-ray powder diffraction (PXRD) patterns were used to evaluate their thermal stability and phase purity. Photoluminescence studies showed that they exhibited strong emitting bands in the visible region with high quantum yields and long luminescent lifetimes. The assembly between nanosized tris((4-carboxyl)phenylduryl)amine ligand and M2+ (M = Zn, Cd, and Pb) ions leads to three new metal-organic frameworks, which show excellent fluorescent properties.

[Effects of broadleaf plantation and Chinese fir (Cunninghamia lanceolata) plantation on soil carbon and nitrogen pools].

PubMed

Wan, Xiao-Hua; Huang, Zhi-Qun; He, Zong-Ming; Hu, Zhen-Hong; Yang, Jing-Yu; Yu, Zai-Peng; Wang, Min-huang

2013-02-01

A comparative study was conducted on the soil C and N pools in a 19-year-old broadleaf plantation and a Chinese fir (Cunninghamia lanceolata) plantation in subtropical China, aimed to understand the effects of tree species on the soil C and N pools. In the broadleaf plantation, the C and N stocks in 0-40 cm soil layer were 99.41 Mg.hm-2 and 6. 18 Mg.hm-2, being 33.1 % and 22. 6 % larger than those in Chinese fir plantation, respectively. The standing biomass and the C and N stocks of forest floor in the broadleaf plantation were 1.60, 1.49, and 1.52 times of those in Chinese fir plantation, respectively, and the differences were statistically significant. There was a significant negative relationship between the forest floor C/N ratio and the soil C and N stocks. In the broadleaf plantation, the fine root biomass in 0-80 cm soil layer was 1.28 times of that in the Chinese fir plantation, and the fine root biomass in 0-10 cm soil layer accounted for 48. 2 % of the total fine root biomass. The C and N stocks in the fine roots in the broadleaf plantation were also higher than those in the Chinese fir plantation. In 0-10 cm soil layer, its C stock had a significant positive relationship with the fine root C stock. It was suggested that as compared with Chinese fir plantation, the soil in broadleaf plantation had a greater potential to accumulate organic carbon.

How Do Trees Know When to Flower? Predicting Reproductive Phenology of Douglas-fir with Changing Winter and Spring Temperatures

NASA Astrophysics Data System (ADS)

Prevey, J.; St Clair, B.; Harrington, C.

2016-12-01

Flowering at the right time is one of the primary ways that plants are adapted to their environment. Trees that flower too early risk cold damage to vulnerable new tissues and those that flower too late miss peak resources or may mistime flowering to coincide with other trees, altering outcrossing rates and gene flow. Past observations indicate that temperature cues over winter and spring influence the timing of flowering in many tree species. Understanding these cues is important for predicting how flowering phenology of trees will change with a changing climate.We developed predictive models of flowering for Douglas-fir, an abundant and commercially important tree in the Pacific Northwest. We assembled over 10,000 flowering observations of trees from 11 sites across western Oregon and Washington. We modeled the dates of flowering using hourly temperature data; our models of flowering were adapted from previous models of vegetative budburst and height growth initiation developed for Douglas-fir. Preliminary results show that both chilling (cold) and forcing (warm) temperatures over winter and spring are important determinants of flowering time for Douglas-fir. This suggests that as spring temperatures warm in the future, Douglas-fir across the Pacific Northwest will flower earlier, unless plants experience insufficient chilling over winter, in which case it is possible that Douglas-fir may flower later than in the past, or not flower at all. At one site, Douglas-fir genotypes from different geographic regions flowered in the same order from year to year, indicating that both temperature and heredity influence flowering. Knowledge of the environmental and genetic cues that drive the timing of flowering can help predict how changes in temperature under various climate models could change flowering time across sites. These models may also indicate the geographic areas where future climate could enhance or reduce flowering of Douglas-fir in the future.

Sensor fusion to enable next generation low cost Night Vision systems

NASA Astrophysics Data System (ADS)

Schweiger, R.; Franz, S.; Löhlein, O.; Ritter, W.; Källhammer, J.-E.; Franks, J.; Krekels, T.

2010-04-01

The next generation of automotive Night Vision Enhancement systems offers automatic pedestrian recognition with a performance beyond current Night Vision systems at a lower cost. This will allow high market penetration, covering the luxury as well as compact car segments. Improved performance can be achieved by fusing a Far Infrared (FIR) sensor with a Near Infrared (NIR) sensor. However, fusing with today's FIR systems will be too costly to get a high market penetration. The main cost drivers of the FIR system are its resolution and its sensitivity. Sensor cost is largely determined by sensor die size. Fewer and smaller pixels will reduce die size but also resolution and sensitivity. Sensitivity limits are mainly determined by inclement weather performance. Sensitivity requirements should be matched to the possibilities of low cost FIR optics, especially implications of molding of highly complex optical surfaces. As a FIR sensor specified for fusion can have lower resolution as well as lower sensitivity, fusing FIR and NIR can solve performance and cost problems. To allow compensation of FIR-sensor degradation on the pedestrian detection capabilities, a fusion approach called MultiSensorBoosting is presented that produces a classifier holding highly discriminative sub-pixel features from both sensors at once. The algorithm is applied on data with different resolution and on data obtained from cameras with varying optics to incorporate various sensor sensitivities. As it is not feasible to record representative data with all different sensor configurations, transformation routines on existing high resolution data recorded with high sensitivity cameras are investigated in order to determine the effects of lower resolution and lower sensitivity to the overall detection performance. This paper also gives an overview of the first results showing that a reduction of FIR sensor resolution can be compensated using fusion techniques and a reduction of sensitivity can be compensated.

Herschel Extreme Lensing Line Observations: [CII] Variations in Galaxies at Redshifts z=1-3*

NASA Technical Reports Server (NTRS)

Malhotra, Sangeeta; Rhoads, James E.; Finkelstein, K.; Yang, Huan; Carilli, Chris; Combes, Francoise; Dassas, Karine; Finkelstein, Steven; Frye, Brenda; Gerin, Maryvonne;

Herschel Extreme Lensing Line Observations: [CII] Variations in Galaxies at Redshifts z=1-3

NASA Astrophysics Data System (ADS)

Malhotra, Sangeeta; Rhoads, James E.; Finkelstein, K.; Yang, Huan; Carilli, Chris; Combes, Françoise; Dassas, Karine; Finkelstein, Steven; Frye, Brenda; Gerin, Maryvonne; Guillard, Pierre; Nesvadba, Nicole; Rigby, Jane; Shin, Min-Su; Spaans, Marco; Strauss, Michael A.; Papovich, Casey

2017-01-01

We observed the [C II] line in 15 lensed galaxies at redshifts 1 < z < 3 using HIFI on the Herschel Space Observatory and detected 14/15 galaxies at 3σ or better. High magnifications enable even modestly luminous galaxies to be detected in [C II] with Herschel. The [C II] luminosity in this sample ranges from 8 × 107 L⊙ to 3.7 × 109 L⊙ (after correcting for magnification), confirming that [C II] is a strong tracer of the ISM at high redshifts. The ratio of the [C II] line to the total far-infrared (FIR) luminosity serves as a measure of the ratio of gas to dust cooling and thus the efficiency of the grain photoelectric heating process. It varies between 3.3% and 0.09%. We compare the [C II]/FIR ratio to that of galaxies at z = 0 and at high redshifts and find that they follow similar trends. The [C II]/FIR ratio is lower for galaxies with higher dust temperatures. This is best explained if increased UV intensity leads to higher FIR luminosity and dust temperatures, but gas heating does not rise due to lower photoelectric heating efficiency. The [C II]/FIR ratio shows weaker correlation with FIR luminosity. At low redshifts highly luminous galaxies tend to have warm dust, so the effects of dust temperature and luminosity are degenerate. Luminous galaxies at high redshifts show a range of dust temperatures, showing that [C II]/FIR correlates most strongly with dust temperature. The [C II] to mid-IR ratio for the HELLO sample is similar to the values seen for low-redshift galaxies, indicating that small grains and PAHs dominate the heating in the neutral ISM, although some of the high [CII]/FIR ratios may be due to turbulent heating. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

HERSCHEL EXTREME LENSING LINE OBSERVATIONS: [C ii] VARIATIONS IN GALAXIES AT REDSHIFTS z = 1–3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malhotra, Sangeeta; Rhoads, James E.; Yang, Huan

We observed the [C ii] line in 15 lensed galaxies at redshifts 1 < z < 3 using HIFI on the Herschel Space Observatory and detected 14/15 galaxies at 3 σ or better. High magnifications enable even modestly luminous galaxies to be detected in [C ii] with Herschel . The [C ii] luminosity in this sample ranges from 8 × 10{sup 7} L {sub ⊙} to 3.7 × 10{sup 9} L {sub ⊙} (after correcting for magnification), confirming that [C ii] is a strong tracer of the ISM at high redshifts. The ratio of the [C ii] line to themore » total far-infrared (FIR) luminosity serves as a measure of the ratio of gas to dust cooling and thus the efficiency of the grain photoelectric heating process. It varies between 3.3% and 0.09%. We compare the [C ii]/FIR ratio to that of galaxies at z = 0 and at high redshifts and find that they follow similar trends. The [C ii]/FIR ratio is lower for galaxies with higher dust temperatures. This is best explained if increased UV intensity leads to higher FIR luminosity and dust temperatures, but gas heating does not rise due to lower photoelectric heating efficiency. The [C ii]/FIR ratio shows weaker correlation with FIR luminosity. At low redshifts highly luminous galaxies tend to have warm dust, so the effects of dust temperature and luminosity are degenerate. Luminous galaxies at high redshifts show a range of dust temperatures, showing that [C ii]/FIR correlates most strongly with dust temperature. The [C ii] to mid-IR ratio for the HELLO sample is similar to the values seen for low-redshift galaxies, indicating that small grains and PAHs dominate the heating in the neutral ISM, although some of the high [CII]/FIR ratios may be due to turbulent heating.« less

China Report, Agriculture, Hubei Agricultural Geography

DTIC Science & Technology

1984-03-14

the growing of crops. Numerous farm crops, forest trees and pasture grasses are suited to growth in soil with a pH of between 6 and 8. Plants do...kinds of timber forest trees Fir [Abies fabri], dragon spruce [Picea asperata], China fir, Pinus armandi, birch, oaks, mountain poplar [Populus...half of which are in timber forests . The trees most used in construc- tion are massoon pine, oak, Chinese fir, Pinus armandi, Chinese pine [ Pinus

Fine-structure mapping of the firA gene, a locus involved in the phenotypic expression of rifampin resistance in Escherichia.

PubMed Central

Lathe, R

1977-01-01

The firA (Ts)200 mutation not only eliminates the resistance to rifampin of certain genetically resistant strains, but, moreover, renders ribonucleic acid synthesis thermolabile. The firA gene has been mapped by P1 tranduction and is located extremely close to the structural gene for deoxyribonucleic acid polymerase III at 4 min on the Escherichia coli linkage map. PMID:330494

Alignment and Polarization Sensitivity Study for the Cassini-Composite InfraRed Spectrometer (CIRS) Far InfraRed (FIR) Interferometer

NASA Technical Reports Server (NTRS)

Crooke, Julie A.; Hagopian, John G.

1998-01-01

The Composite InfraRed Spectrometer (CIRS) instrument flying on the Cassini spacecraft to Saturn is a cryogenic spectrometer with far-infrared (FIR) and mid-infrared (MIR) channels. The CIRS FIR channel is a polarizing interferometer that contains three polarizing grid components. These components are an input polarizer, a polarizing beamsplitter, and an output polarizer/analyzer. They consist of a 1.5 micron thick mylar substrate with 2 gm wide copper wires, with 2 gm spacing (4 micron pitch) photolithographically deposited on the substrate. This paper details the polarization sensitivity studies performed on the output polarizer/analyzer, and the alignment sensitivity studies performed on the input polarizer and beamsplitter components in the FIR interferometer.

Generation of tunable laser sidebands in the far-infrared region

NASA Technical Reports Server (NTRS)

Farhoomand, J.; Frerking, M. A.; Pickett, H. M.; Blake, G. A.

1985-01-01

In recent years, several techniques have been developed for the generation of tunable coherent radiation at submillimeter and far-infrared (FIR) wavelengths. The harmonic generation of conventional microwave sources has made it possible to produce spectrometers capable of continuous operation to above 1000 GHz. However, the sensitivity of such instruments drops rapidly with frequency. For this reason, a great deal of attention is given to laser-based methods, which could cover the entire FIR region. Tunable FIR radiation (approximately 100 nW) has been produced by mixing FIR molecular lasers and conventional microwave sources in both open and closed mixer mounts. The present investigation is concerned with improvements in this approach. These improvements provide approximately thirty times more output power than previous results.

State-dependent impulsive models of integrated pest management (IPM) strategies and their dynamic consequences.

PubMed

Tang, Sanyi; Cheke, Robert A

2005-03-01

A state-dependent impulsive model is proposed for integrated pest management (IPM). IPM involves combining biological, mechanical, and chemical tactics to reduce pest numbers to tolerable levels after a pest population has reached its economic threshold (ET). The complete expression of an orbitally asymptotically stable periodic solution to the model with a maximum value no larger than the given ET is presented, the existence of which implies that pests can be controlled at or below their ET levels. We also prove that there is no periodic solution with order larger than or equal to three, except for one special case, by using the properties of the LambertW function and Poincare map. Moreover, we show that the existence of an order two periodic solution implies the existence of an order one periodic solution. Various positive invariant sets and attractors of this impulsive semi-dynamical system are described and discussed. In particular, several horseshoe-like attractors, whose interiors can simultaneously contain stable order 1 periodic solutions and order 2 periodic solutions, are found and the interior structure of the horseshoe-like attractors is discussed. Finally, the largest invariant set and the sufficient conditions which guarantee the global orbital and asymptotic stability of the order 1 periodic solution in the meaningful domain for the system are given using the Lyapunov function. Our results show that, in theory, a pest can be controlled such that its population size is no larger than its ET by applying effects impulsively once, twice, or at most, a finite number of times, or according to a periodic regime. Moreover, our theoretical work suggests how IPM strategies could be used to alter the levels of the ET in the farmers' favour.

The oscillatory behavior of the CoM facilitates mechanical energy balance between push-off and heel strike.

PubMed

Kim, Seyoung; Park, Sukyung

2012-01-10

Humans use equal push-off and heel strike work during the double support phase to minimize the mechanical work done on the center of mass (CoM) during the gait. Recently, a step-to-step transition was reported to occur over a period of time greater than that of the double support phase, which brings into question whether the energetic optimality is sensitive to the definition of the step-to-step transition. To answer this question, the ground reaction forces (GRFs) of seven normal human subjects walking at four different speeds (1.1-2.4 m/s) were measured, and the push-off and heel strike work for three differently defined step-to-step transitions were computed based on the force, work, and velocity. To examine the optimality of the work and the impulse data, a hybrid theoretical-empirical analysis is presented using a dynamic walking model that allows finite time for step-to-step transitions and incorporates the effects of gravity within this period. The changes in the work and impulse were examined parametrically across a range of speeds. The results showed that the push-off work on the CoM was well balanced by the heel strike work for all three definitions of the step-to-step transition. The impulse data were well matched by the optimal impulse predictions (R(2)>0.7) that minimized the mechanical work done on the CoM during the gait. The results suggest that the balance of push-off and heel strike energy is a consistent property arising from the overall gait dynamics, which implies an inherited oscillatory behavior of the CoM, possibly by spring-like leg mechanics. Copyright © 2011 Elsevier Ltd. All rights reserved.

Single-trial extraction of cognitive evoked potentials by combination of third-order correlation and wavelet denoising.

PubMed

Zhang, Z; Tian, X

2005-01-01

The application of a recently proposed denoising implementation for obtaining cognitive evoked potentials (CEPs) at the single-trial level is shown. The aim of this investigation is to develop the technique of extracting CEPs by combining both the third-order correlation and the wavelet denoising methods. First, the noisy CEPs was passed through a finite impulse response filter whose impulse response is matched with the shape of the noise-free signal. It was shown that it is possible to estimate the filter impulse response on basis of a select third-order correlation slice (TOCS) of the input noisy CEPs. Second, the output from the third-order correlation filter is decomposed with bi-orthogonal splines at 5 levels. The CEPs is reconstructed by wavelet final approximation a5. We study its performance in simulated data as well as in cognitive evoked potentials of normal rat and Alzheimer's disease (AD) model rat. For the simulated data, the method gives a significantly better reconstruction of the single-trial cognitive evoked potentials responses in comparison with the simulated data. Moreover, with this approach we obtain a significantly better estimation of the amplitudes and latencies of the simulated CEPs. For the real data, the method clearly improves the visualization of single-trial CEPs. This allows the calculation of better averages as well as the study of systematic or unsystematic variations between trials.

Three-dimensional water impact at normal incidence to a blunt structure

PubMed Central

Cooker, M. J.; Korobkin, A. A.

2016-01-01

The three-dimensional water impact onto a blunt structure with a spreading rectangular contact region is studied. The structure is mounted on a flat rigid plane with the impermeable curved surface of the structure perpendicular to the plane. Before impact, the water region is a rectangular domain of finite thickness bounded from below by the rigid plane and above by the flat free surface. The front free surface of the water region is vertical, representing the front of an advancing steep wave. The water region is initially advancing towards the structure at a constant uniform speed. We are concerned with the slamming loads acting on the surface of the structure during the initial stage of water impact. Air, gravity and surface tension are neglected. The problem is analysed by using some ideas of pressure-impulse theory, but including the time-dependence of the wetted area of the structure. The flow caused by the impact is three-dimensional and incompressible. The distribution of the pressure-impulse (the time-integral of pressure) over the surface of the structure is analysed and compared with the distributions provided by strip theories. The total impulse exerted on the structure during the impact stage is evaluated and compared with numerical and experimental predictions. An example calculation is presented of water impact onto a vertical rigid cylinder. Three-dimensional effects on the slamming loads are the main concern in this study. PMID:27616912

Spitzer Quasar and ULIRG Evolution Study (QUEST). II. The Spectral Energy Distributions of Palomar-Green Quasars

NASA Astrophysics Data System (ADS)

Netzer, Hagai; Lutz, Dieter; Schweitzer, Mario; Contursi, Alessandra; Sturm, Eckhard; Tacconi, Linda J.; Veilleux, Sylvain; Kim, D.-C.; Rupke, David; Baker, Andrew J.; Dasyra, Kalliopi; Mazzarella, Joseph; Lord, Steven

2007-09-01

This is the second paper studying the QSOs in the Spitzer QUEST sample. Previously we presented new PAH measurements and argued that most of the observed far-infrared (FIR) radiation is due to star-forming activity. Here we present spectral energy distributions (SEDs) by supplementing our data with optical, NIR, and FIR observations. We define two subgroups, of ``weak FIR'' and ``strong FIR'' QSOs, and a third group of FIR nondetections. Assuming a starburst origin for the FIR, we obtain ``intrinsic'' active galactic nucleus (AGN) SEDs by subtracting a starburst template from the mean SEDs. The resulting SEDs are remarkably similar for all groups. They show three distinct peaks corresponding to two silicate emission features and a 3 μm bump, which we interpret as the signature of the hottest AGN dust. They also display drops beyond ~20 μm that we interpret as the signature of the minimum temperature (~200 K) dust. This component must be optically thin to explain the silicate emission and the slope of the long-wavelength continuum. We discuss the merits of an alternative model in which most of the FIR emission is due to AGN heating. Such models are unlikely to explain the properties of our QSOs, but they cannot be ruled out for more luminous objects. We also find correlations between the luminosity at 5100 Å and two infrared starburst indicators: L(60 μm) and L(PAH 7.7 μm). The correlation of L(5100 Å) with L(60 μm) can be used to measure the relative growth rates and lifetimes of the black hole and the new stars.

Effect of ultraviolet and far infrared radiation on microbial decontamination and quality of cumin seeds.

PubMed

Erdoğdu, S Belgin; Ekiz, H İbrahim

2011-01-01

Cumin seeds might be exposed to a high level of natural bacterial contamination, and this could potentially create a public health risk besides leading to problems in exportation. Ultraviolet (UVC) and far infrared (FIR) radiation has low penetration power, and due to that, there might be no detrimental defects to the products during a possible decontamination process. Therefore, the objective of this study was to determine the effect of UVC and FIR treatment on microbial decontamination and quality of cumin seeds. For this purpose, FIR treatment at different exposure times and temperatures were applied followed by constant UVC treatment with an intensity of 10.5 mW/cm² for 2 h. Total mesophilic aerobic bacteria of the cumin seeds were decreased to the target level of 10⁴ CFU/g after 1.57, 2.8, and 4.8 min FIR treatment at 300, 250, and 200 °C, respectively, following a 2 h UVC treatment. Under the given conditions, a complete elimination for total yeast and molds were obtained while there were no significant changes in volatile oil content and color of the cumin seeds. Consequently, combined UVC and FIR treatment was determined to be a promising method for decontamination of the cumin seeds. This research attempts to apply UVC and far infrared (FIR) radiation for pasteurization of cumin seeds. The data suggested that combined UVC and FIR radiation treatments can become a promising new method for pasteurization of cumin seeds without causing any detrimental defect to the quality parameters. The results of this industry partnered (Kadioglu Baharat, Mersin, Turkey--http://www.kadioglubaharat.com) study were already applied in industrial scale production lines. © 2011 Institute of Food Technologists®

Positive-pressure ventilation during transport: a randomized crossover study of self-inflating and flow-inflating resuscitators in a simulation model.

PubMed

Lucy, Malcolm J; Gamble, Jonathan J; Daku, Brian L; Bryce, Rhonda D; Rana, Masud

2014-12-01

Positive-pressure ventilation during transport of intubated patients is generally delivered via a hand-pressurized device. Of these devices, self-inflating resuscitators (SIR) and flow-inflating resuscitators (FIR) constitute the two major types used. Selection of a particular device for transport, however, remains largely an institutional practice. To evaluate the hypothesis that transport ventilation goals of intubated pediatric patients are better achieved using an FIR compared to an SIR. This randomized crossover simulation study compared the performance of SIR and FIR among anesthesia providers in a pediatric transport scenario. Subjects hand-ventilated a test lung while simultaneously maneuvering a stretcher bed to simulate patient transport. Hand ventilation was carried out using a Jackson-Rees circuit (FIR) and a Laerdal pediatric silicone resuscitator (SIR). The primary outcome was the proportion of total breaths delivered within the predefined target PIP/PEEP range (30+/- 3, 10+/- 3 cm H2O). Secondary outcomes included proportion of total breaths delivered with operationally defined unacceptable breath variables (PIP > 35 cm H2O or PEEP < 5 cm H2O). Overall, participants were four times more likely to deliver target breaths and one-third less likely to deliver unacceptable breaths using the FIR compared to the SIR. When comparing device performance, a 44% increase in the proportions of target breaths and a 40.4% decrease in unacceptable breaths using the FIR were observed (P < 0.0001 for both). Hand ventilation during patient transport is superior using the FIR compared to the SIR to achieve target ventilatory goals and avoid unacceptable ventilatory cycles. © 2014 John Wiley & Sons Ltd.

MO-DE-207A-07: Filtered Iterative Reconstruction (FIR) Via Proximal Forward-Backward Splitting: A Synergy of Analytical and Iterative Reconstruction Method for CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, H

Purpose: This work is to develop a general framework, namely filtered iterative reconstruction (FIR) method, to incorporate analytical reconstruction (AR) method into iterative reconstruction (IR) method, for enhanced CT image quality. Methods: FIR is formulated as a combination of filtered data fidelity and sparsity regularization, and then solved by proximal forward-backward splitting (PFBS) algorithm. As a result, the image reconstruction decouples data fidelity and image regularization with a two-step iterative scheme, during which an AR-projection step updates the filtered data fidelity term, while a denoising solver updates the sparsity regularization term. During the AR-projection step, the image is projected tomore » the data domain to form the data residual, and then reconstructed by certain AR to a residual image which is in turn weighted together with previous image iterate to form next image iterate. Since the eigenvalues of AR-projection operator are close to the unity, PFBS based FIR has a fast convergence. Results: The proposed FIR method is validated in the setting of circular cone-beam CT with AR being FDK and total-variation sparsity regularization, and has improved image quality from both AR and IR. For example, AIR has improved visual assessment and quantitative measurement in terms of both contrast and resolution, and reduced axial and half-fan artifacts. Conclusion: FIR is proposed to incorporate AR into IR, with an efficient image reconstruction algorithm based on PFBS. The CBCT results suggest that FIR synergizes AR and IR with improved image quality and reduced axial and half-fan artifacts. The authors was partially supported by the NSFC (#11405105), the 973 Program (#2015CB856000), and the Shanghai Pujiang Talent Program (#14PJ1404500).« less

Durability of structural lumber products after exposure at 82°C and 80% relative humidity

Treesearch

David W. Green; James W. Evans; Cherilyn A. Hatfield; Pamela J. Byrd

2005-01-01

Solid-sawn lumber (Douglas-fir, southern pine, Spruce–Pine–Fir, and yellow-poplar), laminated veneer lumber (Douglas-fir, southern pine, and yellow-poplar), and laminated strand lumber (aspen and yellow-poplar) were heated continuously at 82°C (180°F) and 80% relative humidity (RH) for periods of up to 24 months. The lumber was then reconditioned to room temperature at...

Pedestrian Detection in Far-Infrared Daytime Images Using a Hierarchical Codebook of SURF

PubMed Central

Besbes, Bassem; Rogozan, Alexandrina; Rus, Adela-Maria; Bensrhair, Abdelaziz; Broggi, Alberto

2015-01-01

One of the main challenges in intelligent vehicles concerns pedestrian detection for driving assistance. Recent experiments have showed that state-of-the-art descriptors provide better performances on the far-infrared (FIR) spectrum than on the visible one, even in daytime conditions, for pedestrian classification. In this paper, we propose a pedestrian detector with on-board FIR camera. Our main contribution is the exploitation of the specific characteristics of FIR images to design a fast, scale-invariant and robust pedestrian detector. Our system consists of three modules, each based on speeded-up robust feature (SURF) matching. The first module allows generating regions-of-interest (ROI), since in FIR images of the pedestrian shapes may vary in large scales, but heads appear usually as light regions. ROI are detected with a high recall rate with the hierarchical codebook of SURF features located in head regions. The second module consists of pedestrian full-body classification by using SVM. This module allows one to enhance the precision with low computational cost. In the third module, we combine the mean shift algorithm with inter-frame scale-invariant SURF feature tracking to enhance the robustness of our system. The experimental evaluation shows that our system outperforms, in the FIR domain, the state-of-the-art Haar-like Adaboost-cascade, histogram of oriented gradients (HOG)/linear SVM (linSVM) and MultiFtrpedestrian detectors, trained on the FIR images. PMID:25871724

Efficacy and safety of far infrared radiation in lymphedema treatment: clinical evaluation and laboratory analysis.

PubMed

Li, Ke; Zhang, Zheng; Liu, Ning Fei; Feng, Shao Qing; Tong, Yun; Zhang, Ju Fang; Constantinides, Joannis; Lazzeri, Davide; Grassetti, Luca; Nicoli, Fabio; Zhang, Yi Xin

2017-04-01

Swelling is the most common symptom of extremities lymphedema. Clinical evaluation and laboratory analysis were conducted after far infrared radiation (FIR) treatment on the main four components of lymphedema: fluid, fat, protein, and hyaluronan. Far infrared radiation is a kind of hyperthermia therapy with several and additional benefits as well as promoting microcirculation flow and improving collateral lymph circumfluence. Although FIR therapy has been applied for several years on thousands of lymphedema patients, there are still few studies that have reported the biological effects of FIR on lymphatic tissue. In this research, we investigate the effects of far infrared rays on the major components of lymphatic tissue. Then, we explore the effectiveness and safety of FIR as a promising treatment modality of lymphedema. A total of 32 patients affected by lymphedema in stage II and III were treated between January 2015 and January 2016 at our department. After therapy, a significant decrease of limb circumference measurements was noted and improving of quality of life was registered. Laboratory examination showed the treatment can also decrease the deposition of fluid, fat, hyaluronan, and protein, improving the swelling condition. We believe FIR treatment could be considered as both an alternative monotherapy and a useful adjunctive to the conservative or surgical lymphedema procedures. Furthermore, the real and significant biological effects of FIR represent possible future applications in wide range of the medical field.

Detection of the 158 Micrometers[CII] Transition at z=1.3: Evidence for a Galaxy-Wide Starburst

NASA Technical Reports Server (NTRS)

Hailey-Dunsheath, S.; Nikola, T.; Oberst, T. E.; Parshley, S. C.; Benford, D. J.; Staguhn, J. G.; Tucker, C. E.

2010-01-01

We report the detection of 158 micron [C II] fine-structure line emission from MIPS J142824.0+352619, a hyperluminous ( L(sub IR) approximates 10(exp 13) L (sub solar)) starburst galaxy at z = 1.3. The line is bright, corresponding to a fraction L(sub [Cu II] L(sub Fir) approximates 2 x 10(exp -3) of the far-IR (FIR) continuum. The [C II], CO, and FIR continuum emission may be modeled as arising from photodissociation regions (PDRs) that have a characteristic gas density of n approximates 10(exp 4.2) /cm(exp 3) , and that are illuminated by a far-UV radiation field approximately 10(exp 3.2) times more intense than the local interstellar radiation field. The mass in these PDRs accounts for approximately half of the molecular gas mass in this galaxy. The L(sub [CII])/L(sub FIR) ratio is higher than observed in local ultralummous infrared galaxies or in the few high-redshift QSOs detected in [C II], but the L(sub [CII])/L(sub FIR) and L(sub CO)/L(sub FIR) ratios are similar to the values seen in nearby starburst galaxies. This suggests that MIPS J142824.0+352619 is a scaled-up version of a starburst nucleus, with the burst extended over several kiloparsecs.

Physiology and growth of advance Picea rubens and Abies balsamea regeneration following different canopy openings.

PubMed

Dumais, Daniel; Prévost, Marcel

2014-02-01

We examined the ecophysiology and growth of 0.3-1.3 m tall advance red spruce (Picea rubens Sarg.) and balsam fir (Abies balsamea [L.] Mill.) regeneration during a 5-year period following the application of different harvest types producing three sizes of canopy openings: (i) small gaps (<100 m(2) in area; SMA) created by partial uniform single-tree harvest; (ii) irregular gaps of intermediate size (100-300 m(2); INT) created by group-selection harvest (removal of groups of trees, mainly balsam fir, with uniform partial removal between groups); and (iii) large circular gaps (700 m(2); LAR) created by patch-selection harvest (removal of trees in 30-m diameter circular areas with uniform partial removal between gaps). An unharvested control (CON) was monitored for comparison. At the ecophysiological level, we mainly found differences in light-saturated photosynthesis of red spruce and specific leaf area of balsam fir among treatments. Consequently, we observed good height growth of both species in CON and INT, but fir surpassed spruce in SMA and LAR. Results suggest that intermediate 100-300 m(2) irregular openings create microenvironmental conditions that may promote short-term ecophysiology and growth of red spruce, allowing the species to compete with balsam fir advance regeneration. Finally, results observed for spruce in large 700-m(2) openings confirm its inability to grow as rapidly as fir in comparable open conditions.

[Post-logging organic matter recovery in forest ecosystems of eastern Baikal region].

PubMed

Vedrova, E F; Mukhortova, L V; Ivanov, V V; Krivobokov, L V; Boloneva, M V

2010-01-01

The dynamics of organic matter accumulated in the soil and main vegetation elements was analyzed for post-logging forest ecosystem succession series in eastern Baikal region. The phytomass was found to allocate up 63 and 50% of carbon in undisturbed Scots pine and fir stands, respectively. The post-logging phytomass contribution to the total carbon pool appeared to decrease down to 16% in Scots pine and 6% in fir stands. In Scots pine stands, carbon storage was determined to account for almost 70% of the initial carbon 60 years after logging. In 50- to 55-year-old fir stands, carbon recovered its initial pool only by 10%. Soil carbon recorded in recently logged Scots pine and fir sites appeared to be 5 and 16 times that accumulated in the phytomass, respectively. The ratio between phytomass carbon and soil organic matter recovered back to the prelogging level in Scots pine stands by the age of 50-60 years. While phytomass carbon also increased in fir stand of the same age, it did not reach the level of the control stand.

Repellent Activity of Botanical Oils against Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae)

PubMed Central

Kuhns, Emily H.; Martini, Xavier; Hoyte, Angel; Stelinski, Lukasz L.

2016-01-01

The Asian citrus psyllid, Diaphorina citri Kuwayama, is the insect vector of the pathogen causing huanglongbing. We selected three botanical oils to evaluate behavioral activity against D. citri. In laboratory olfactometer assays, fir oil was repellent to D. citri females, while litsea and citronella oils elicited no response from D. citri females. In choice settling experiments, D. citri settled almost completely on control plants rather than on plants treated with fir oil at a 9.5 mg/day release rate. Therefore, we conducted field trials to determine if fir oil reduced D. citri densities in citrus groves. We found no repellency of D. citri from sweet orange resets that were treated with fir oil dispensers releasing 10.4 g/day/tree as compared with control plots. However, we found a two-week decrease in populations of D. citri as compared with controls when the deployment rate of these dispensers was doubled. Our results suggest that treatment of citrus with fir oil may have limited activity as a stand-alone management tool for D. citri and would require integration with other management practices. PMID:27429006

Repellent Activity of Botanical Oils against Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae).

PubMed

Kuhns, Emily H; Martini, Xavier; Hoyte, Angel; Stelinski, Lukasz L

2016-07-14

The Asian citrus psyllid, Diaphorina citri Kuwayama, is the insect vector of the pathogen causing huanglongbing. We selected three botanical oils to evaluate behavioral activity against D. citri. In laboratory olfactometer assays, fir oil was repellent to D. citri females, while litsea and citronella oils elicited no response from D. citri females. In choice settling experiments, D. citri settled almost completely on control plants rather than on plants treated with fir oil at a 9.5 mg/day release rate. Therefore, we conducted field trials to determine if fir oil reduced D. citri densities in citrus groves. We found no repellency of D. citri from sweet orange resets that were treated with fir oil dispensers releasing 10.4 g/day/tree as compared with control plots. However, we found a two-week decrease in populations of D. citri as compared with controls when the deployment rate of these dispensers was doubled. Our results suggest that treatment of citrus with fir oil may have limited activity as a stand-alone management tool for D. citri and would require integration with other management practices.

A flattened cloud core in NGC 2024

NASA Technical Reports Server (NTRS)

Ho, Paul T. P.; Peng, Yun-Lou; Torrelles, Jose M.; Gomez, Jose F.; Rodriguez, Luis F.; Canto, Jorge

1993-01-01

The (J, K) (1, 1) and (2, 2) NH3 lines were mapped toward a molecular cloud core in NGC 2024 using the VLA in its C/D-configuration. This region is associated with one of the most highly collimated molecular outflows. We find that the molecular condensations associated with the far-infrared sources FIR 5, FIR 6, and FIR 7 have kinetic temperatures of about 40 K. We also find line broadening toward FIR 6 and FIR 7. This suggests that these condensations may not be protostars heated by gravitational energy released during collapse but that they have an internal heating source. A flattened structure of ammonia emission is found extending parallel to the unipolar CO outflow structure, but displaced systematically to the east. If the NH3 emission traces the denser gas environment, there is no evidence that a dense gas structure is confining the molecular outflow. Instead, the location of the high-velocity outflow along the surface of the NH3 structure suggests that a wind is sweeping material from the surface of this elongated cloud core.

Finite element cochlea box model - Mechanical and electrical analysis of the cochlea

NASA Astrophysics Data System (ADS)

Nikolic, Milica; Teal, Paul D.; Isailovic, Velibor; Filipović, Nenad

2015-12-01

The primary role of the cochlea is to transform external sound stimuli into mechanical vibrations and then to neural impulses which are sent to the brain. A simplified cochlea box model was developed using the finite element method. Firstly, a mechanical model of the cochlea was analyzed. The box model consists of the basilar membrane and two fluid chambers - the scala vestibuli and scala tympani. The third chamber, the scala media, was neglected in the mechanical analysis. The best agreement with currently available analytical and experimental results was obtained when behavior of the fluid in the chambers was described using the wave acoustic equation and behavior of the basilar membrane was modeled with Newtonian dynamics. The obtained results show good frequency mapping. The second approach was to use an active model of the cochlea in which the Organ of Corti was included. The operation of the Organ of Corti involves the generation of current, caused by mechanical vibration. This current in turn causes a force applied to the basilar membrane, creating in this way an active feedback mechanism. A state space representation of the electro-mechanical model from existing literature was implemented and a first comparison with the finite element method is presented.

Eco-physiological characteristics and variation in water source use between montane Douglas-Fir and lodgepole pine trees in southwestern Alberta

NASA Astrophysics Data System (ADS)

Andrews, S.; Flanagan, L. B.

2009-12-01

Winter weather on the Canadian prairies is now warmer and drier than 50 years ago and this has implications for soil water re-charge in montane ecosystems with consequences for tree and ecosystem function. We used measurements of the hydrogen isotope ratio of tree stem water to analyze the use of different water sources (winter snow melt, ground water, summer precipitation) in two montane forest sites, one dominated by Douglas-Fir and the other dominated by lodgepole pine trees. On average during the growing season (May-October) stem water in both Douglas-Fir and lodgepole pine trees was composed of 60% summer precipitation. However, during late summer Douglas-Fir trees showed an increased use of ground water as summer precipitation was minimal and ground water was accessible at the bottom of a relatively large soil reservoir. The low summer precipitation and reduced soil water availability in the shallow soils at the lodgepole pine site resulted in severely reduced photosynthetic capacity in late summer. Increased precipitation during the autumn resulted in recovery of photosynthetic gas exchange in lodgepole pine before winter dormancy was induced by low temperatures. Stomatal limitation of photosynthesis, as estimated from measurements of the carbon isotope composition of leaf tissue, was higher in Douglas-Fir than lodgepole pine. This was also associated with lower midday water potential values in Douglas-Fir and sapwood cross-sectional area that was only 70% of that measured in lodgepole pine. The vulnerability of xylem to loss of conductivity with declines in water potential was very similar between the two species. However, midday water potential in Douglas-Fir approached values where cavitation and loss of conductivity were apparent, while in lodgepole pine midday water potential was always much higher than the point at which loss of hydraulic conductivity occurred. These data suggest that, despite the presence of Douglas-Fir on deeper and higher quality soils, lodgepole pine appears to have eco-physiological characteristics that allow it to better withstand and recover from exposure to summer water deficits that may increase in association with trends to warmer and drier conditions.

Silvical characteristics of bigcone Douglas-fir (Pseudotsuga macrocarpa [Vasey] Mayr)

Treesearch

Gerald W. Gause

1966-01-01

Describes the climatic, edaphic, physiographic, and biotic habitat conditions of the natural range of bigcone Douglas-fir (Pseudotsuga macrocarpa [Vasey] Mayr) and how this tree reproduces, grows, and dies.

Estimating stand age for Douglas-fir.

Treesearch

Floyd A. Johnson

1954-01-01

Stand age for Douglas-fir has been defined as the average age of dominant and codominant trees. It is commonly estimated by measuring the age of several dominants and codominants and computing their arithmetic average.

Integrated programmable photonic filter on the silicon-on-insulator platform.

PubMed

Liao, Shasha; Ding, Yunhong; Peucheret, Christophe; Yang, Ting; Dong, Jianji; Zhang, Xinliang

2014-12-29

We propose and demonstrate a silicon-on-insulator (SOI) on-chip programmable filter based on a four-tap finite impulse response structure. The photonic filter is programmable thanks to amplitude and phase modulation of each tap controlled by thermal heaters. We further demonstrate the tunability of the filter central wavelength, bandwidth and variable passband shape. The tuning range of the central wavelength is at least 42% of the free spectral range. The bandwidth tuning range is at least half of the free spectral range. Our scheme has distinct advantages of compactness, capability for integrating with electronics.

Space-Frequency Sampling Criteria for Electromagnetic Scattering of a Finite Object.

DTIC Science & Technology

1985-08-01

An impulsive magnetic field incident upon a solid conducting body, sets up current - ’ 3 on the surface. As a result, 3 = n x RT will start...sphere and a cube using cubic, isotropic, and rectangular box confinement units are presented in Chapter IV. The efficiency definition proves to e a...8217S’IDRNGE FILE NAME: ACCPEr 30,FNAME2 30 PDR1’ RT (Al 0) IF (aCM.BD.𔃼’) GO MI 35 C C CIII/FR MI MPIT’UME(LINEA) ANDV PHASE (RADIAN) C WD 33 1-l.NsTEP XII~w

Incidence of the pine wood nematode in green coniferous sawn wood in Oregon and California. Forest Service research note

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dwinell, L.D.

1993-05-01

Samples of green sawn Douglas-fir, redwood, ponderosa pine, and white fir were collected in August and September 1992 from seven mills in Oregon and California, and assayed for the pine wood nematode, Bursaphelenchus xylophilus. The mills produced about 108 million board feet during the survey period. The pine wood nematode was not found in any of the 424 samples of Douglas-fir, the 192 of redwood, or the 3 of white fir. The nematode was recovered from 8 of 105 samples of green ponderosa pine lumber from a mill in Oregon. These eight samples contained an average of 54 pine woodmore » nematodes per gram of dry weight. This is the first report of the pine wood nematode in Oregon.« less

Dust silicate emission in FIR/submm

NASA Astrophysics Data System (ADS)

Coupeaud, A.; Demyk, K.; Mény, C.; Nayral, C.

2010-12-01

The far-infrared to millimeter wavelength (FIR-mm) range in astronomical observations is dominated by the thermal emission from large (10-100 nm) and cold (10-20 K) dust grains, which are in thermal equilibrium with the interstellar radiation field. However, the physics of the FIR-mm emission from such cold matter is not well understood as shown by the observed dependence with the temperature of the spectral index of the dust emissivity β and by the observed far infrared excess. Interestingly, a similar behaviour is observed in experiments of characterization of the spectral properties of dust analogues. We present a study of the optical properties of analogues of interstellar silicate grains at low temperature in the FIR/submm range aiming to understand their peculiar behaviour. Such studies are essential for the interpretation of the Herschel and Planck data.

Frontiers in Reproduction (FIR): An Assessment of Success1

PubMed Central

Ascoli, Mario; Mebane, Dorianne; Fazleabas, Asgerally T.

2016-01-01

The Frontiers in Reproduction (FIR) course has been held annually since 1998 at the Marine Biological Laboratories in Woods Hole, MA. The primary purpose of the course is to train young reproductive biologists in cutting-edge techniques that would strengthen their career opportunities. An initial evaluation of the FIR course was conducted by surveying the participants who took the course between 1998 and 2002. The findings of this survey were published in Biology of Reproduction in 2006, which highlighted the overall positive impact the course had on the training and upward career trajectory of the participants during the first 5 yr. The current study was designed to access the continued impact of FIR at the 10-yr mark by evaluating the participants who took the course between 1998 and 2008 using two different survey mechanisms. Based on these evaluations and feedback from the participants, it was evident that 1) FIR continues to have a significant positive impact on the careers of the participants, 2) the majority of the participants continue to be involved in research or administration related to the reproductive sciences, 3) nearly 90% of the attendees have been successful in obtaining funding for their research, and 4) most alumni have published at least five manuscripts in higher impact journals since they took the course. Therefore, it is evident that FIR participants are highly successful and continue to significantly impact the advances in the reproductive sciences worldwide. PMID:27335071

Comparison of international normalized ratio audit parameters in patients enrolled in GARFIELD-AF and treated with vitamin K antagonists.

PubMed

Fitzmaurice, David A; Accetta, Gabriele; Haas, Sylvia; Kayani, Gloria; Lucas Luciardi, Hector; Misselwitz, Frank; Pieper, Karen; Ten Cate, Hugo; Turpie, Alexander G G; Kakkar, Ajay K

2016-08-01

Vitamin K antagonist (VKA) therapy for stroke prevention in atrial fibrillation (AF) requires monitoring of the international normalized ratio (INR). We evaluated the agreement between two INR audit parameters, frequency in range (FIR) and proportion of time in the therapeutic range (TTR), using data from a global population of patients with newly diagnosed non-valvular AF, the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF). Among 17 168 patients with 1-year follow-up data available at the time of the analysis, 8445 received VKA therapy (±antiplatelet therapy) at enrolment, and of these patients, 5066 with ≥3 INR readings and for whom both FIR and TTR could be calculated were included in the analysis. In total, 70 905 INRs were analysed. At the patient level, TTR showed higher values than FIR (mean, 56·0% vs 49·8%; median, 59·7% vs 50·0%). Although patient-level FIR and TTR values were highly correlated (Pearson correlation coefficient [95% confidence interval; CI], 0·860 [0·852-0·867]), estimates from individuals showed widespread disagreement and variability (Lin's concordance coefficient [95% CI], 0·829 [0·821-0·837]). The difference between FIR and TTR explained 17·4% of the total variability of measurements. These results suggest that FIR and TTR are not equivalent and cannot be used interchangeably. © 2016 John Wiley & Sons Ltd.

THE FLUIDS AND COMBUSTION FACILITY: ENABLING THE EXPLORATION OF SPACE

NASA Technical Reports Server (NTRS)

Weiland, Karen J.; Gati, Frank G.; Hill, Myron E.; OMalley, Terence; Zurawski, Robert L.

2005-01-01

The Fluids and Combustion Facility (FCF) is an International Space Station facility designed to support physical and biological research as well as technology experiments in space. The FCF consists of two racks called the Combustion Integrated Rack (CIR) and the Fluids Integrated Rack (FIR). The capabilities of the CIR and the FIR and plans for their utilization will support the President s vision for space exploration. The CIR will accommodate physical research and technology experiments that address needs in the areas of spacecraft fire prevention, detection and suppression, incineration of solid wastes, and power generation. Initial experiments will provide data to support design decisions for exploration spacecraft. The CIR provides a large sealed chamber in a near-weightless environment. The chamber supports many simulated atmospheres including lunar or Martian environments. The FIR will accommodate experiments that address needs for advanced life support, power, propulsion, and spacecraft thermal control systems. The FIR can also serve as a platform for experiments that address human health and performance, medical technologies, and biological sciences. The FIR provides a large volume for payload hardware, reconfigurable diagnostics, customizable software, active rack-level vibration isolation, and data acquisition and management in a nearly uniform temperature environment.

The Fluids and Combustion Facility: Enabling the Exploration of Space

NASA Technical Reports Server (NTRS)

Weiland, Karen J.; Gati, Frank G.; Hill, Myron E.; O'Malley Terence F.; Zurawski, Robert L.

2005-01-01

The Fluids and Combustion Facility (FCF) is an International Space Station facility designed to support physical and biological research as well as technology experiments in space. The FCF consists of two racks called the Combustion Integrated Rack (CIR) and the Fluids Integrated Rack (FIR). The capabilities of the CIR and the FIR and plans for their utilization will support the President's vision for space exploration. The CIR will accommodate physical research and technology experiments that address needs in the areas of spacecraft fire prevention, detection and suppression, incineration of solid wastes, and power generation. Initial experiments will provide data to support design decisions for exploration spacecraft. The CIR provides a large sealed chamber in a near-weightless environment. The chamber supports many simulated atmospheres including lunar or Martian environments. The FIR will accommodate experiments that address needs for advanced life support, power, propulsion, and spacecraft thermal control systems. The FIR can also serve as a platform for experiments that address human health and performance, medical technologies, and biological sciences. The FIR provides a large volume for payload hardware, reconfigurable diagnostics, customizable software, active rack-level vibration isolation, and data acquisition and management in a nearly uniform temperature environment.

Efficient and Accurate Optimal Linear Phase FIR Filter Design Using Opposition-Based Harmony Search Algorithm

PubMed Central

Saha, S. K.; Dutta, R.; Choudhury, R.; Kar, R.; Mandal, D.; Ghoshal, S. P.

2013-01-01

In this paper, opposition-based harmony search has been applied for the optimal design of linear phase FIR filters. RGA, PSO, and DE have also been adopted for the sake of comparison. The original harmony search algorithm is chosen as the parent one, and opposition-based approach is applied. During the initialization, randomly generated population of solutions is chosen, opposite solutions are also considered, and the fitter one is selected as a priori guess. In harmony memory, each such solution passes through memory consideration rule, pitch adjustment rule, and then opposition-based reinitialization generation jumping, which gives the optimum result corresponding to the least error fitness in multidimensional search space of FIR filter design. Incorporation of different control parameters in the basic HS algorithm results in the balancing of exploration and exploitation of search space. Low pass, high pass, band pass, and band stop FIR filters are designed with the proposed OHS and other aforementioned algorithms individually for comparative optimization performance. A comparison of simulation results reveals the optimization efficacy of the OHS over the other optimization techniques for the solution of the multimodal, nondifferentiable, nonlinear, and constrained FIR filter design problems. PMID:23844390

Efficient and accurate optimal linear phase FIR filter design using opposition-based harmony search algorithm.

PubMed

Saha, S K; Dutta, R; Choudhury, R; Kar, R; Mandal, D; Ghoshal, S P

2013-01-01

In this paper, opposition-based harmony search has been applied for the optimal design of linear phase FIR filters. RGA, PSO, and DE have also been adopted for the sake of comparison. The original harmony search algorithm is chosen as the parent one, and opposition-based approach is applied. During the initialization, randomly generated population of solutions is chosen, opposite solutions are also considered, and the fitter one is selected as a priori guess. In harmony memory, each such solution passes through memory consideration rule, pitch adjustment rule, and then opposition-based reinitialization generation jumping, which gives the optimum result corresponding to the least error fitness in multidimensional search space of FIR filter design. Incorporation of different control parameters in the basic HS algorithm results in the balancing of exploration and exploitation of search space. Low pass, high pass, band pass, and band stop FIR filters are designed with the proposed OHS and other aforementioned algorithms individually for comparative optimization performance. A comparison of simulation results reveals the optimization efficacy of the OHS over the other optimization techniques for the solution of the multimodal, nondifferentiable, nonlinear, and constrained FIR filter design problems.

The Douglas-Fir Genome Sequence Reveals Specialization of the Photosynthetic Apparatus in Pinaceae

PubMed Central

Neale, David B.; McGuire, Patrick E.; Wheeler, Nicholas C.; Stevens, Kristian A.; Crepeau, Marc W.; Cardeno, Charis; Zimin, Aleksey V.; Puiu, Daniela; Pertea, Geo M.; Sezen, U. Uzay; Casola, Claudio; Koralewski, Tomasz E.; Paul, Robin; Gonzalez-Ibeas, Daniel; Zaman, Sumaira; Cronn, Richard; Yandell, Mark; Holt, Carson; Langley, Charles H.; Yorke, James A.; Salzberg, Steven L.; Wegrzyn, Jill L.

2017-01-01

A reference genome sequence for Pseudotsuga menziesii var. menziesii (Mirb.) Franco (Coastal Douglas-fir) is reported, thus providing a reference sequence for a third genus of the family Pinaceae. The contiguity and quality of the genome assembly far exceeds that of other conifer reference genome sequences (contig N50 = 44,136 bp and scaffold N50 = 340,704 bp). Incremental improvements in sequencing and assembly technologies are in part responsible for the higher quality reference genome, but it may also be due to a slightly lower exact repeat content in Douglas-fir vs. pine and spruce. Comparative genome annotation with angiosperm species reveals gene-family expansion and contraction in Douglas-fir and other conifers which may account for some of the major morphological and physiological differences between the two major plant groups. Notable differences in the size of the NDH-complex gene family and genes underlying the functional basis of shade tolerance/intolerance were observed. This reference genome sequence not only provides an important resource for Douglas-fir breeders and geneticists but also sheds additional light on the evolutionary processes that have led to the divergence of modern angiosperms from the more ancient gymnosperms. PMID:28751502

Active field control (AFC) -electro-acoustic enhancement system using acoustical feedback control

NASA Astrophysics Data System (ADS)

Miyazaki, Hideo; Watanabe, Takayuki; Kishinaga, Shinji; Kawakami, Fukushi

2003-10-01

AFC is an electro-acoustic enhancement system using FIR filters to optimize auditory impressions, such as liveness, loudness, and spaciousness. This system has been under development at Yamaha Corporation for more than 15 years and has been installed in approximately 50 venues in Japan to date. AFC utilizes feedback control techniques for recreation of reverberation from the physical reverberation of the room. In order to prevent coloration problems caused by a closed loop condition, two types of time-varying control techniques are implemented in the AFC system to ensure smooth loop gain and a sufficient margin in frequency characteristics to prevent instability. Those are: (a) EMR (electric microphone rotator) -smoothing frequency responses between microphones and speakers by changing the combinations of inputs and outputs periodically; (b) fluctuating-FIR -smoothing frequency responses of FIR filters and preventing coloration problems caused by fixed FIR filters, by moving each FIR tap periodically on time axis with a different phase and time period. In this paper, these techniques are summarized. A block diagram of AFC using new equipment named AFC1, which has been developed at Yamaha Corporation and released recently in the US, is also presented.

Detection of the 158 Micrometers[CII] Transition at z=1.3: Evidence for a Galaxy-Wide Starburst

NASA Technical Reports Server (NTRS)

Hailey-Dunsheath, S.; Nikola, T.; Stacey, G. J.; Oberst, T. E.; Parshley, S. C.; Benford, D. J.; Staguhn, J. G.; Tucker, C. E.

2010-01-01

We report the detection of 158 micrometer [C II] fine-structure line emission from MIPS J 142824.0+3526l9, a hyperluminous (L(sub IR) approx. 10(exp 13) Solar Luminosity starburst galaxy at z = 1.3. The line is bright, corresponding to a fraction L[C II]/L(sub FIR) approx. equals 2 x l0(exp -3) of the far-IR(FIR) continuum. The [C II], CO, and FIR continuum emission may be modeled as arising from photodissociation regions (PDRs) that have a characteristic gas density of n approx. 10(exp 4.2)/cu cm., and that are illuminated by a far-UV radiation field approx. 10(exp 3.2) times more intense than the local interstellar radiation field. The mass in these PDRs accounts for approximately half of the molecular gas mass in this galaxy. The L[C II]/L(sub F1R) ratio is higher than observed in local ultraluminous infrared galaxies or in the few high-redshift QSOs detected in [C II], but the L[CII]/L(sub FIR) and L(sub CO)/L(sub FIR) ratios are similar to the values seen in nearby starburst galaxies

Mice and voles prefer spruce seeds

Treesearch

Herschel G. Abbott; Arthur C. Hart

1961-01-01

When spruce-fir stands in the Northeast are cut, balsam fir seedlings often predominate in the regeneration that follows. Most landowners would prefer to have the spruce; but they do not get it, and they wonder why.

Estimating seed crops of conifer and hardwood species

Treesearch

Philip M. McDonald

1992-01-01

Cone, acorn, and berry crops of ponderosa pine (Pinus ponderosa Dougl. ex Laws. var. ponderosa), sugar pine (Pinus lambertiana Dougl.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), California white fir (Abies concolor var. lowiana (Gord...

Impulse response of a two-dimensional rough surface overlying an inhomogeneous, nondispersive medium: A hybrid model

NASA Astrophysics Data System (ADS)

Keiffer, Richard; Novarini, Jorge; Norton, Guy

2002-11-01

A numerical model to calculate the impulse response of a two-dimensional, impenetrable, rough surface directly in the time domain has been recently introduced [R. S. Keiffer and J. C. Novarini, J. Acoust. Soc. Am. 107, 27-39 (2000)]. This model is based on wedge diffraction theory and assumes the half-space containing the source and receiver is homogeneous. In this work, the model is extended to handle media where the index of refraction varies with depth by merging the scattering model with a ray-based propagation model. The resulting hybrid model is tested against a finite-difference time-domain (FDTD) method for backscattering from a corrugated surface in the presence of a refractive layer. This new model can be applied, for example, to calculate acoustic reverberation from the sea surface in cases where the water mass is inhomogeneous and dispersion is negligible. [Work supported by ONR/NRL (PE 61153N-32) and by grants of computer time DoD HPC Shared Resource Center at Stennis Space Center, MS.

Determination of elastic mechanical characteristics of surface coatings from analysis of signals obtained by impulse excitation

NASA Astrophysics Data System (ADS)

Nyaguly, E.; Craştiu, I.; Deac, S.; Gozman-Pop, C.; Drăgănescu, G.; Bereteu, L.

2018-01-01

Most of the surface coatings are based on the synthetic polymers, which are substances composed from very large molecules that form tough, flexible, adhesive films when applied to surfaces. The other components of surface coverings materials are pigments that provide colour, opacity, gloss and other properties. Surface coatings are two-phase composite materials: constitute a polymer matrix on the one side, and on the other side of the pigments and additives dispersed in the matrix. Their role is not only aesthetically but also to ensure anticorrosive protection or even improve some mechanical properties of coated surfaces. In this paper it will follow, starting from the mechanical properties of the substrate, the metallic sheet in general, to determine the new properties of the assembly of substrate and the two coating layers, also the determination of mechanical properties of the layers. From the analysis of vibroacoustic signals obtained by the impulse excitation of the sample, one can determine the elasticity modulus. These results come to validate the results based on finite element analysis (FEA) of the same samples.

Lp-stability (1 less than or equal to p less than or equal to infinity) of multivariable nonlinear time-varying feedback systems that are open-loop unstable. [noting unstable convolution subsystem forward control and time varying nonlinear feedback

NASA Technical Reports Server (NTRS)

Callier, F. M.; Desoer, C. A.

1973-01-01

A class of multivariable, nonlinear time-varying feedback systems with an unstable convolution subsystem as feedforward and a time-varying nonlinear gain as feedback was considered. The impulse response of the convolution subsystem is the sum of a finite number of increasing exponentials multiplied by nonnegative powers of the time t, a term that is absolutely integrable and an infinite series of delayed impulses. The main result is a theorem. It essentially states that if the unstable convolution subsystem can be stabilized by a constant feedback gain F and if incremental gain of the difference between the nonlinear gain function and F is sufficiently small, then the nonlinear system is L(p)-stable for any p between one and infinity. Furthermore, the solutions of the nonlinear system depend continuously on the inputs in any L(p)-norm. The fixed point theorem is crucial in deriving the above theorem.