Absolute phase map recovery of two fringe patterns with flexible selection of fringe wavelengths.

Science.gov (United States)

Long, Jiale; Xi, Jiangtao; Zhu, Ming; Cheng, Wenqing; Cheng, Rui; Li, Zhongwei; Shi, Yusheng

2014-03-20

A novel approach is proposed to unwrap the phase maps of two fringe patterns in fringe pattern projection-based profilometry. In contrast to existing techniques, where spatial frequencies (i.e., the number of fringes on a pattern) of the two fringe patterns must be integers and coprime, the proposed method is applicable for any two fringe patterns with different fringe wavelengths (i.e., the number of pixels in a fringe) and thus provides more flexibility in the use of fringe patterns. Moreover, compared to the existing techniques, the proposed method is simpler in its implementation and has better antierror capability. Theoretical analysis and experiment results are presented to confirm the effectiveness of the proposed method.

A fringe projector-based study of the Brighter-Fatter Effect in LSST CCDs

Science.gov (United States)

Gilbertson, W.; Nomerotski, A.; Takacs, P.

2017-09-01

To achieve the goals of the Large Synoptic Survey Telescope for Dark Energy science requires a detailed understanding of CCD sensor effects. One such sensor effect is the Point Spread Function (PSF) increasing with flux, alternatively called the `Brighter-Fatter Effect.' In this work a novel approach was tested to perform the PSF measurements in the context of the Brighter-Fatter Effect employing a Michelson interferometer to project a sinusoidal fringe pattern onto the CCD. The Brighter-Fatter effect predicts that the fringe pattern should become asymmetric in the intensity pattern as the brighter peaks corresponding to a larger flux are smeared by a larger PSF. By fitting the data with a model that allows for a changing PSF, the strength of the Brighter-Fatter effect can be evaluated.

A Self-Powered and Autonomous Fringing Field Capacitive Sensor Integrated into a Micro Sprinkler Spinner to Measure Soil Water Content.

Science.gov (United States)

da Costa, Eduardo Ferreira; de Oliveira, Nestor E; Morais, Flávio J O; Carvalhaes-Dias, Pedro; Duarte, Luis Fernando C; Cabot, Andreu; Siqueira Dias, J A

2017-03-12

We present here the design and fabrication of a self-powered and autonomous fringing field capacitive sensor to measure soil water content. The sensor is manufactured using a conventional printed circuit board and includes a porous ceramic. To read the sensor, we use a circuit that includes a 10 kHz triangle wave generator, an AC amplifier, a precision rectifier and a microcontroller. In terms of performance, the sensor's capacitance (measured in a laboratory prototype) increases up to 5% when the volumetric water content of the porous ceramic changed from 3% to 36%, resulting in a sensitivity of S = 15.5 pF per unity change. Repeatability tests for capacitance measurement showed that the θ v sensor's root mean square error is 0.13%. The average current consumption of the system (sensor and signal conditioning circuit) is less than 1.5 μ A, which demonstrates its suitability for being powered by energy harvesting systems. We developed a complete irrigation control system that integrates the sensor, an energy harvesting module composed of a microgenerator installed on the top of a micro sprinkler spinner, and a DC/DC converter circuit that charges a 1 F supercapacitor. The energy harvesting module operates only when the micro sprinkler spinner is irrigating the soil, and the supercapacitor is fully charged to 5 V in about 3 h during the first irrigation. After the first irrigation, with the supercap fully charged, the system can operate powered only by the supercapacitor for approximately 23 days, without any energy being harvested.

Fringe pattern denoising via image decomposition.

Science.gov (United States)

Fu, Shujun; Zhang, Caiming

2012-02-01

Filtering off noise from a fringe pattern is one of the key tasks in optical interferometry. In this Letter, using some suitable function spaces to model different components of a fringe pattern, we propose a new fringe pattern denoising method based on image decomposition. In our method, a fringe image is divided into three parts: low-frequency fringe, high-frequency fringe, and noise, which are processed in different spaces. An adaptive threshold in wavelet shrinkage involved in this algorithm improves its denoising performance. Simulation and experimental results show that our algorithm obtains smooth and clean fringes with different frequencies while preserving fringe features effectively.

Theoretical and experimental study of low-finesse extrinsic Fabry-Perot interferometric fiber optic sensors

Science.gov (United States)

Han, Ming

In this dissertation, detailed and systematic theoretical and experimental study of low-finesse extrinsic Fabry-Perot interferometric (EFPI) fiber optic sensors together with their signal processing methods for white-light systems are presented. The work aims to provide a better understanding of the operational principle of EFPI fiber optic sensors, and is useful and important in the design, optimization, fabrication and application of single mode fiber(SMF) EFPI (SMF-EFPI) and multimode fiber (MMF) EFPI (MMF-EFPI) sensor systems. The cases for SMF-EFPI and MMF-EFPI sensors are separately considered. In the analysis of SMF-EFPI sensors, the light transmitted in the fiber is approximated by a Gaussian beam and the obtained spectral transfer function of the sensors includes an extra phase shift due to the light coupling in the fiber end-face. This extra phase shift has not been addressed by previous researchers and is of great importance for high accuracy and high resolution signal processing of white-light SMF-EFPI systems. Fringe visibility degradation due to gap-length increase and sensor imperfections is studied. The results indicate that the fringe visibility of a SMF-EFPI sensor is relatively insensitive to the gap-length change and sensor imperfections. Based on the spectral fringe pattern predicated by the theory of SMF-EFPI sensors, a novel curve fitting signal processing method (Type 1 curve-fitting method) is presented for white-light SMF-EFPI sensor systems. Other spectral domain signal processing methods including the wavelength-tracking, the Type 2-3 curve fitting, Fourier transform, and two-point interrogation methods are reviewed and systematically analyzed. Experiments were carried out to compare the performances of these signal processing methods. The results have shown that the Type 1 curve fitting method achieves high accuracy, high resolution, large dynamic range, and the capability of absolute measurement at the same time, while others either

An improved sensor for precision detection of in situ stem water content using a frequency domain fringing capacitor.

Science.gov (United States)

Zhou, Haiyang; Sun, Yurui; Tyree, Melvin T; Sheng, Wenyi; Cheng, Qiang; Xue, Xuzhang; Schumann, Henrik; Schulze Lammers, Peter

2015-04-01

One role of stems is that of water storage. The water content of stems increases and decreases as xylem water potential increases and decreases, respectively. Hence, a nondestructive method to measure stem water content (StWC) = (volume of water) : (volume of stem), could be useful in monitoring the drought stress status of plants. We introduce a frequency domain inner fringing capacitor-sensor for measuring StWC which operates at 100 MHz frequency. The capacitor-sensor consists of two wave guides (5-mm-wide braided metal) that snugly fit around the surface of a stem with a spacing of 4-5 mm between guides. Laboratory measurements on analog stems reveals that the DC signal output responds linearly to the relative dielectric constant of the analog stem, is most sensitive to water content between the waveguides to a depth of c. 3 mm from the stem surface, and calibrations based on the gravimetric water loss of excised stems of plants revealed a resolution in StWC of < ± 0.001 v/ v. The sensor performed very well on whole plants with a 100-fold increased resolution compared with previous frequency domain and time domain reflectometry methods and, hence, may be very useful for future research requiring nondestructive measurements of whole plants. © European Union 2014. New Phytologist © 2014 New Phytologist Trust.

Principal-vector-directed fringe-tracking technique.

Science.gov (United States)

Zhang, Zhihui; Guo, Hongwei

2014-11-01

Fringe tracking is one of the most straightforward techniques for analyzing a single fringe pattern. This work presents a principal-vector-directed fringe-tracking technique. It uses Gaussian derivatives for estimating fringe gradients and uses hysteresis thresholding for segmenting singular points, thus improving the principal component analysis method. Using it allows us to estimate the principal vectors of fringes from a pattern with high noise. The fringe-tracking procedure is directed by these principal vectors, so that erroneous results induced by noise and other error-inducing factors are avoided. At the same time, the singular point regions of the fringe pattern are identified automatically. Using them allows us to determine paths through which the "seed" point for each fringe skeleton is easy to find, thus alleviating the computational burden in processing the fringe pattern. The results of a numerical simulation and experiment demonstrate this method to be valid.

Estimation of fringe orientation for optical fringe patterns with poor quality based on Fourier transform.

Science.gov (United States)

Tang, Chen; Wang, Zhifang; Wang, Linlin; Wu, Jian; Gao, Tao; Yan, Si

2010-02-01

Fringe orientation represents an important property of fringes. The estimation of orientation from a poor quality fringe image is still a challenging problem faced in this area. This paper introduces a new approach for estimating optical fringe orientation with a poor quality image. This approach is based on the power spectrum analysis of the Fourier transform. We evaluate the performance of this algorithm via application to a variety of test cases and comparison with the widely used gradient-based method and accumulate-differences method. The experimental results show that our method is capable of calculating fringe orientation robustly even when the quality of fringe images is considerably low because of high or low density, high noise, and low contrast. Under the same conditions, our accuracy is even better than that obtained with the gradient-based and accumulate-differences methods, especially for fringe images with poor quality.

Simplified absolute phase retrieval of dual-frequency fringe patterns in fringe projection profilometry

Science.gov (United States)

Lu, Jin; Mo, Rong; Sun, Huibin; Chang, Zhiyong; Zhao, Xiaxia

2016-04-01

In fringe projection profilometry, a simplified method is proposed to recover absolute phase maps of two-frequency fringe patterns by using a unique mapping rule. The mapping rule is designed from the rounded phase values to the fringe order of each pixel. Absolute phase can be recovered by the fringe order maps. Unlike the existing techniques, where the lowest frequency of dual- or multiple-frequency fringe patterns must be single, the presented method breaks the limitation and simplifies the procedure of phase unwrapping. Additionally, due to many issues including ambient light, shadow, sharp edges, step height boundaries and surface reflectivity variations, a novel framework of automatically identifying and removing invalid phase values is also proposed. Simulations and experiments have been carried out to validate the performances of the proposed method.

Simplified fringe order correction for absolute phase maps recovered with multiple-spatial-frequency fringe projections

International Nuclear Information System (INIS)

Ding, Yi; Peng, Kai; Lu, Lei; Zhong, Kai; Zhu, Ziqi

2017-01-01

Various kinds of fringe order errors may occur in the absolute phase maps recovered with multi-spatial-frequency fringe projections. In existing methods, multiple successive pixels corrupted by fringe order errors are detected and corrected pixel-by-pixel with repeating searches, which is inefficient for applications. To improve the efficiency of multiple successive fringe order corrections, in this paper we propose a method to simplify the error detection and correction by the stepwise increasing property of fringe order. In the proposed method, the numbers of pixels in each step are estimated to find the possible true fringe order values, repeating the search in detecting multiple successive errors can be avoided for efficient error correction. The effectiveness of our proposed method is validated by experimental results. (paper)

A Self-Powered and Autonomous Fringing Field Capacitive Sensor Integrated into a Micro Sprinkler Spinner to Measure Soil Water Content

Directory of Open Access Journals (Sweden)

Eduardo Ferreira da Costa

2017-03-01

Full Text Available We present here the design and fabrication of a self-powered and autonomous fringing field capacitive sensor to measure soil water content. The sensor is manufactured using a conventional printed circuit board and includes a porous ceramic. To read the sensor, we use a circuit that includes a 10 kHz triangle wave generator, an AC amplifier, a precision rectifier and a microcontroller. In terms of performance, the sensor’s capacitance (measured in a laboratory prototype increases up to 5% when the volumetric water content of the porous ceramic changed from 3% to 36%, resulting in a sensitivity of S = 15.5 pF per unity change. Repeatability tests for capacitance measurement showed that the θ v sensor’s root mean square error is 0.13%. The average current consumption of the system (sensor and signal conditioning circuit is less than 1.5 μ A, which demonstrates its suitability for being powered by energy harvesting systems. We developed a complete irrigation control system that integrates the sensor, an energy harvesting module composed of a microgenerator installed on the top of a micro sprinkler spinner, and a DC/DC converter circuit that charges a 1 F supercapacitor. The energy harvesting module operates only when the micro sprinkler spinner is irrigating the soil, and the supercapacitor is fully charged to 5 V in about 3 h during the first irrigation. After the first irrigation, with the supercap fully charged, the system can operate powered only by the supercapacitor for approximately 23 days, without any energy being harvested.

Fringe pattern denoising using coherence-enhancing diffusion.

Science.gov (United States)

Wang, Haixia; Kemao, Qian; Gao, Wenjing; Lin, Feng; Seah, Hock Soon

2009-04-15

Electronic speckle pattern interferometry is one of the methods measuring the displacement on object surfaces in which fringe patterns need to be evaluated. Noise is one of the key problems affecting further processing and reducing measurement quality. We propose an application of coherence-enhancing diffusion to fringe-pattern denoising. It smoothes a fringe pattern along directions both parallel and perpendicular to fringe orientation with suitable diffusion speeds to more effectively reduce noise and improve fringe-pattern quality. It is a generalized work of Tang's et al.'s [Opt. Lett.33, 2179 (2008)] model that only smoothes a fringe pattern along fringe orientation. Since our model diffuses a fringe pattern with an additional direction, it is able to denoise low-density fringes as well as improve denoising effectiveness for high-density fringes. Theoretical analysis as well as simulation and experimental verifications are addressed.

49 CFR 25.525 - Fringe benefits.

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2010-10-01

... 49 Transportation 1 2010-10-01 2010-10-01 false Fringe benefits. 25.525 Section 25.525... Employment in Education Programs or Activities Prohibited § 25.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

36 CFR 1211.525 - Fringe benefits.

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2010-07-01

... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Fringe benefits. 1211.525... Prohibited § 1211.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

22 CFR 229.525 - Fringe benefits.

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2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Fringe benefits. 229.525 Section 229.525... Employment in Education Programs or Activities Prohibited § 229.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

32 CFR 196.525 - Fringe benefits.

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2010-07-01

... 32 National Defense 2 2010-07-01 2010-07-01 false Fringe benefits. 196.525 Section 196.525... Prohibited § 196.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

22 CFR 146.525 - Fringe benefits.

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2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Fringe benefits. 146.525 Section 146.525... Employment in Education Programs or Activities Prohibited § 146.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

28 CFR 54.525 - Fringe benefits.

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2010-07-01

... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Fringe benefits. 54.525 Section 54.525... in Employment in Education Programs or Activities Prohibited § 54.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

10 CFR 1042.525 - Fringe benefits.

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2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Fringe benefits. 1042.525 Section 1042.525 Energy... Education Programs or Activities Prohibited § 1042.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life...

44 CFR 19.525 - Fringe benefits.

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2010-10-01

... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Fringe benefits. 19.525... Programs or Activities Prohibited § 19.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or...

43 CFR 41.525 - Fringe benefits.

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2010-10-01

... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Fringe benefits. 41.525 Section 41.525... in Employment in Education Programs or Activities Prohibited § 41.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

14 CFR 1253.525 - Fringe benefits.

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2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Fringe benefits. 1253.525 Section 1253.525... in Employment in Education Programs or Activities Prohibited § 1253.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

6 CFR 17.525 - Fringe benefits.

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2010-01-01

... 6 Domestic Security 1 2010-01-01 2010-01-01 false Fringe benefits. 17.525 Section 17.525 Domestic... in Employment in Education Programs or Activities Prohibited § 17.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, the term fringe benefits means any medical...

10 CFR 5.525 - Fringe benefits.

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2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Fringe benefits. 5.525 Section 5.525 Energy NUCLEAR... Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

40 CFR 5.525 - Fringe benefits.

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2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Fringe benefits. 5.525 Section 5.525... in Employment in Education Programs or Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

31 CFR 28.525 - Fringe benefits.

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2010-07-01

... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Fringe benefits. 28.525 Section 28... the Basis of Sex in Employment in Education Programs or Activities Prohibited § 28.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any...

29 CFR 36.525 - Fringe benefits.

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2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Fringe benefits. 36.525 Section 36.525 Labor Office of the... Activities Prohibited § 36.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

Sensor concentrator unit for the Continuous Automated Vault Inventory System

Energy Technology Data Exchange (ETDEWEB)

Nodine, R.N.; Lenarduzzi, R.

1997-06-01

The purpose of this document is to describe the use and operation of the sensor concentrator in the Continuous Automated Vault Inventory System (CAVIS). The CAVIS electronically verifies the presence of items of stored special nuclear material (SNM). US Department of Energy orders require that stored SNM be inventoried periodically to provide assurance that the material is secure. Currently this inventory is a highly manual activity, requiring personnel to enter the storage vaults. Using a CAVIS allows the frequency of physical inventories to be significantly reduced, resulting in substantial cost savings, increased security, and improved safety. The electronic inventory of stored SNM requires two different types of sensors for each item. The two sensors measure different parameters of the item, usually weight and gamma rays. A CAVIS is constructed using four basic system components: sensors, sensor concentrators, a data collection unit, and a database/user interface unit. One sensor concentrator supports the inventory of up to 20 items (40 sensors) and continuously takes readings from the item sensors. On request the sensor concentrator outputs the most recent sensor readings to the data collection unit. The information transfer takes place over a RS485 communications link. The data collection unit supports from 1 to 120 sensor concentrators (1 to 2,400 items) and is referred to as the Sensor Polling and Configuration System (SPCS). The SPCS is connected by a secure Transmission Control Protocol/Internet Protocol (TCP/IP) network to the database/user interface unit, which is referred to as the Graphical Facility Information Center (GraFIC). A CAVIS containing more than 2,400 items is supported by connecting additional SPCS units to the GraFIC.

Sensor concentrator unit for the Continuous Automated Vault Inventory System

International Nuclear Information System (INIS)

Nodine, R.N.; Lenarduzzi, R.

1997-06-01

The purpose of this document is to describe the use and operation of the sensor concentrator in the Continuous Automated Vault Inventory System (CAVIS). The CAVIS electronically verifies the presence of items of stored special nuclear material (SNM). US Department of Energy orders require that stored SNM be inventoried periodically to provide assurance that the material is secure. Currently this inventory is a highly manual activity, requiring personnel to enter the storage vaults. Using a CAVIS allows the frequency of physical inventories to be significantly reduced, resulting in substantial cost savings, increased security, and improved safety. The electronic inventory of stored SNM requires two different types of sensors for each item. The two sensors measure different parameters of the item, usually weight and gamma rays. A CAVIS is constructed using four basic system components: sensors, sensor concentrators, a data collection unit, and a database/user interface unit. One sensor concentrator supports the inventory of up to 20 items (40 sensors) and continuously takes readings from the item sensors. On request the sensor concentrator outputs the most recent sensor readings to the data collection unit. The information transfer takes place over a RS485 communications link. The data collection unit supports from 1 to 120 sensor concentrators (1 to 2,400 items) and is referred to as the Sensor Polling and Configuration System (SPCS). The SPCS is connected by a secure Transmission Control Protocol/Internet Protocol (TCP/IP) network to the database/user interface unit, which is referred to as the Graphical Facility Information Center (GraFIC). A CAVIS containing more than 2,400 items is supported by connecting additional SPCS units to the GraFIC

Circular fringe projection profilometry.

Science.gov (United States)

Zhao, Hong; Zhang, Chunwei; Zhou, Changquan; Jiang, Kejian; Fang, Meiqi

2016-11-01

In this Letter, a novel three-dimensional (3D) measurement method, called the circular fringe projection profilometry (CFPP), is proposed. Similar to the conventional fringe projection profilometry, CFPP also requires fringe pattern projection and capture, phase demodulation, and phase unwrapping. However, it works with a totally different mechanism. CFPP recovers the height of a point by calculating its distance to the optical center of a projector along the optical axis. This distance is calculated with the aid of the divergence angle of a projected light ray and the distance between the measured point and the optical axis. The distance between the measured point and the optical axis is detected by a camera with telecentric lenses, while the divergence angle can be calculated from the phase of a captured circular fringe pattern. The validity of CFPP is confirmed by a set of experiments.

Measurement of instantaneous rotational speed using double-sine-varying-density fringe pattern

Science.gov (United States)

Zhong, Jianfeng; Zhong, Shuncong; Zhang, Qiukun; Peng, Zhike

2018-03-01

Fast and accurate rotational speed measurement is required both for condition monitoring and faults diagnose of rotating machineries. A vision- and fringe pattern-based rotational speed measurement system was proposed to measure the instantaneous rotational speed (IRS) with high accuracy and reliability. A special double-sine-varying-density fringe pattern (DSVD-FP) was designed and pasted around the shaft surface completely and worked as primary angular sensor. The rotational angle could be correctly obtained from the left and right fringe period densities (FPDs) of the DSVD-FP image sequence recorded by a high-speed camera. The instantaneous angular speed (IAS) between two adjacent frames could be calculated from the real-time rotational angle curves, thus, the IRS also could be obtained accurately and efficiently. Both the measurement principle and system design of the novel method have been presented. The influence factors on the sensing characteristics and measurement accuracy of the novel system, including the spectral centrobaric correction method (SCCM) on the FPD calculation, the noise sources introduce by the image sensor, the exposure time and the vibration of the shaft, were investigated through simulations and experiments. The sampling rate of the high speed camera could be up to 5000 Hz, thus, the measurement becomes very fast and the change in rotational speed was sensed within 0.2 ms. The experimental results for different IRS measurements and characterization of the response property of a servo motor demonstrated the high accuracy and fast measurement of the proposed technique, making it attractive for condition monitoring and faults diagnosis of rotating machineries.

48 CFR 731.372 - Fringe benefits.

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2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Fringe benefits. 731.372 Section 731.372 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL....372 Fringe benefits. USAID's policies on certain fringe benefits related to overseas service...

Computer-assisted techniques to evaluate fringe patterns

Science.gov (United States)

Sciammarella, Cesar A.; Bhat, Gopalakrishna K.

1992-01-01

Strain measurement using interferometry requires an efficient way to extract the desired information from interferometric fringes. Availability of digital image processing systems makes it possible to use digital techniques for the analysis of fringes. In the past, there have been several developments in the area of one dimensional and two dimensional fringe analysis techniques, including the carrier fringe method (spatial heterodyning) and the phase stepping (quasi-heterodyning) technique. This paper presents some new developments in the area of two dimensional fringe analysis, including a phase stepping technique supplemented by the carrier fringe method and a two dimensional Fourier transform method to obtain the strain directly from the discontinuous phase contour map.

41 CFR 101-4.525 - Fringe benefits.

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2010-07-01

... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Fringe benefits. 101-4... in Employment in Education Programs or Activities Prohibited § 101-4.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

Fringe image analysis based on the amplitude modulation method.

Science.gov (United States)

Gai, Shaoyan; Da, Feipeng

2010-05-10

A novel phase-analysis method is proposed. To get the fringe order of a fringe image, the amplitude-modulation fringe pattern is carried out, which is combined with the phase-shift method. The primary phase value is obtained by a phase-shift algorithm, and the fringe-order information is encoded in the amplitude-modulation fringe pattern. Different from other methods, the amplitude-modulation fringe identifies the fringe order by the amplitude of the fringe pattern. In an amplitude-modulation fringe pattern, each fringe has its own amplitude; thus, the order information is integrated in one fringe pattern, and the absolute fringe phase can be calculated correctly and quickly with the amplitude-modulation fringe image. The detailed algorithm is given, and the error analysis of this method is also discussed. Experimental results are presented by a full-field shape measurement system where the data has been processed using the proposed algorithm. (c) 2010 Optical Society of America.

Fringes in FTIR spectroscopy revisited: understanding and modelling fringes in infrared spectroscopy of thin films.

Science.gov (United States)

Konevskikh, Tatiana; Ponossov, Arkadi; Blümel, Reinhold; Lukacs, Rozalia; Kohler, Achim

2015-06-21

The appearance of fringes in the infrared spectroscopy of thin films seriously hinders the interpretation of chemical bands because fringes change the relative peak heights of chemical spectral bands. Thus, for the correct interpretation of chemical absorption bands, physical properties need to be separated from chemical characteristics. In the paper at hand we revisit the theory of the scattering of infrared radiation at thin absorbing films. Although, in general, scattering and absorption are connected by a complex refractive index, we show that for the scattering of infrared radiation at thin biological films, fringes and chemical absorbance can in good approximation be treated as additive. We further introduce a model-based pre-processing technique for separating fringes from chemical absorbance by extended multiplicative signal correction (EMSC). The technique is validated by simulated and experimental FTIR spectra. It is further shown that EMSC, as opposed to other suggested filtering methods for the removal of fringes, does not remove information related to chemical absorption.

Real-time determination of fringe pattern frequencies: An application to pressure measurement

Science.gov (United States)

Sciammarella, Cesar A.; Piroozan, Parham

2007-05-01

Retrieving information in real time from fringe patterns is a topic of a great deal of interest in scientific and engineering applications of optical methods. This paper presents a method for fringe frequency determination based on the capability of neural networks to recognize signals that are similar but not identical to signals used to train the neural network. Sampled patterns are generated by calibration and stored in memory. Incoming patterns are analyzed by a back-propagation neural network at the speed of the recording device, a CCD camera. This method of information retrieval is utilized to measure pressures on a boundary layer flow. The sensor combines optics and electronics to analyze dynamic pressure distributions and to feed information to a control system that is capable to preserve the stability of the flow.

Fringe order error in multifrequency fringe projection phase unwrapping: reason and correction.

Science.gov (United States)

Zhang, Chunwei; Zhao, Hong; Zhang, Lu

2015-11-10

A multifrequency fringe projection phase unwrapping algorithm (MFPPUA) is important to fringe projection profilometry, especially when a discontinuous object is measured. However, a fringe order error (FOE) may occur when MFPPUA is adopted. An FOE will result in error to the unwrapped phase. Although this kind of phase error does not spread, it brings error to the eventual 3D measurement results. Therefore, an FOE or its adverse influence should be obviated. In this paper, reasons for the occurrence of an FOE are theoretically analyzed and experimentally explored. Methods to correct the phase error caused by an FOE are proposed. Experimental results demonstrate that the proposed methods are valid in eliminating the adverse influence of an FOE.

18 CFR 1317.525 - Fringe benefits.

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2010-04-01

... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Fringe benefits. 1317... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

13 CFR 113.525 - Fringe benefits.

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2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Fringe benefits. 113.525 Section... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

38 CFR 23.525 - Fringe benefits.

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2010-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Fringe benefits. 23.525... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

45 CFR 2555.525 - Fringe benefits.

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2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false Fringe benefits. 2555.525 Section 2555.525 Public... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

34 CFR 106.56 - Fringe benefits.

Science.gov (United States)

2010-07-01

... 34 Education 1 2010-07-01 2010-07-01 false Fringe benefits. 106.56 Section 106.56 Education... benefits. (a) Fringe benefits defined. For purposes of this part, fringe benefits means: Any medical, hospital, accident, life insurance or retirement benefit, service, policy or plan, any profit-sharing or...

45 CFR 618.525 - Fringe benefits.

Science.gov (United States)

2010-10-01

... 45 Public Welfare 3 2010-10-01 2010-10-01 false Fringe benefits. 618.525 Section 618.525 Public... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

24 CFR 3.525 - Fringe benefits.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Fringe benefits. 3.525 Section 3... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

Making sense of nanocrystal lattice fringes

International Nuclear Information System (INIS)

Fraundorf, P.; Qin Wentao; Moeck, Peter; Mandell, Eric

2005-01-01

The orientation dependence of thin-crystal lattice fringes can be gracefully quantified using fringe-visibility maps, a direct-space analog of Kikuchi maps [Nishikawa and Kikuchi, Nature (London) 121, 1019 (1928)]. As in navigation of reciprocal space with the aid of Kikuchi lines, fringe-visibility maps facilitate acquisition of crystallographic information from lattice images. In particular, these maps can help researchers to determine the three-dimensional lattice of individual nanocrystals, to 'fringe-fingerprint' collections of randomly oriented particles, and to measure local specimen thickness with only a modest tilt. Since the number of fringes in an image increases with maximum spatial-frequency squared, these strategies (with help from more precise goniometers) will be more useful as aberration correction moves resolutions into the subangstrom range

Quality-guided orientation unwrapping for fringe direction estimation.

Science.gov (United States)

Wang, Haixia; Kemao, Qian

2012-02-01

Fringe patterns produced by various optical interferometric techniques encode information such as shape, deformation, and refractive index. Denoising and demodulation are two important procedures to retrieve information from a single closed fringe pattern. Various existing denoising and demodulation techniques require fringe direction/orientation during the processing. Fringe orientation is often easier to obtain but fringe direction is needed in some demodulation techniques. A quality-guided orientation unwrapping scheme is proposed to estimate direction from orientation. Two techniques, one based on windowed Fourier ridges and the other based on fringe gradient, are proposed for the quality-guided orientation unwrapping scheme. The direction qualities are compared for both simulated and experimental fringe patterns. Their application to demodulation technique is also given.

Fringing-field effects in acceleration columns

International Nuclear Information System (INIS)

Yavor, M.I.; Weick, H.; Wollnik, H.

1999-01-01

Fringing-field effects in acceleration columns are investigated, based on the fringing-field integral method. Transfer matrices at the effective boundaries of the acceleration column are obtained, as well as the general transfer matrix of the region separating two homogeneous electrostatic fields with different field strengths. The accuracy of the fringing-field integral method is investigated

Control bandwidth improvements in GRAVITY fringe tracker by switching to a synchronous real time computer architecture

Science.gov (United States)

Abuter, Roberto; Dembet, Roderick; Lacour, Sylvestre; di Lieto, Nicola; Woillez, Julien; Eisenhauer, Frank; Fedou, Pierre; Phan Duc, Than

2016-08-01

The new VLTI (Very Large Telescope Interferometer) 1 instrument GRAVITY5, 22, 23 is equipped with a fringe tracker16 able to stabilize the K-band fringes on six baselines at the same time. It has been designed to achieve a performance for average seeing conditions of a residual OPD (Optical Path Difference) lower than 300 nm with objects brighter than K = 10. The control loop implementing the tracking is composed of a four stage real time computer system compromising: a sensor where the detector pixels are read in and the OPD and GD (Group Delay) are calculated; a controller receiving the computed sensor quantities and producing commands for the piezo actuators; a concentrator which combines both the OPD commands with the real time tip/tilt corrections offloading them to the piezo actuator; and finally a Kalman15 parameter estimator. This last stage is used to monitor current measurements over a window of few seconds and estimate new values for the main Kalman15 control loop parameters. The hardware and software implementation of this design runs asynchronously and communicates the four computers for data transfer via the Reflective Memory Network3. With the purpose of improving the performance of the GRAVITY5, 23 fringe tracking16, 22 control loop, a deviation from the standard asynchronous communication mechanism has been proposed and implemented. This new scheme operates the four independent real time computers involved in the tracking loop synchronously using the Reflective Memory Interrupts2 as the coordination signal. This synchronous mechanism had the effect of reducing the total pure delay of the loop from 3.5 [ms] to 2.0 [ms] which then translates on a better stabilization of the fringes as the bandwidth of the system is substantially improved. This paper will explain in detail the real time architecture of the fringe tracker in both is synchronous and synchronous implementation. The achieved improvements on reducing the delay via this mechanism will be

Mobile robot multi-sensor unit for unsupervised gas discrimination in uncontrolled environments

OpenAIRE

Xing, Yuxin; Vincent, Timothy A.; Cole, Marina; Gardner, Julian W.; Fan, Han; Hernandez Bennetts, Victor; Schaffernicht, Erik; Lilienthal, Achim

2017-01-01

In this work we present a novel multi-sensor unit to detect and discriminate unknown gases in uncontrolled environments. The unit includes three metal oxide (MOX) sensors with CMOS micro heaters, a plasmonic enhanced non-dispersive infra-red (NDIR) sensor, a commercial temperature humidity sensor, and a flow sensor. The proposed sensing unit was evaluated with plumes of gases (propanol, ethanol and acetone) in both, a laboratory setup on a gas testing bench and on-board a mobile robot operati...

On-Line Fringe Tracking and Prediction at IOTA

Science.gov (United States)

Wilson, Edward; Mah, Robert; Lau, Sonie (Technical Monitor)

1999-01-01

The Infrared/Optical Telescope Array (IOTA) is a multi-aperture Michelson interferometer located on Mt. Hopkins near Tucson, Arizona. To enable viewing of fainter targets, an on-line fringe tracking system is presently under development at NASA Ames Research Center. The system has been developed off-line using actual data from IOTA, and is presently undergoing on-line implementation at IOTA. The system has two parts: (1) a fringe tracking system that identifies the center of a fringe packet by fitting a parametric model to the data; and (2) a fringe packet motion prediction system that uses characteristics of past fringe packets to predict fringe packet motion. Combined, this information will be used to optimize on-line the scanning trajectory, resulting in improved visibility of faint targets. Fringe packet identification is highly accurate and robust (99% of the 4000 fringe packets were identified correctly, the remaining 1% were either out of the scan range or too noisy to be seen) and is performed in 30-90 milliseconds on a Pentium II-based computer. Fringe packet prediction, currently performed using an adaptive linear predictor, delivers a 10% improvement over the baseline of predicting no motion.

Wages or Fringes?

DEFF Research Database (Denmark)

Eriksson, Tor Viking; Kristensen, Nicolai

The two key predictions of hedonic wage theory are that there is a trade-o¤ between wages and nonmonetary rewards and that the latter can be used as a sorting device by firms to attract and retain the kind of employees they desire. Empirical analysis of these topics are scarce as they require...... negative wage-fringe trade-offs, con-siderable heterogeneity in willingness to pay for fringe benefits, and signs of sorting. The findings imply that personnel economics models can be applied also to the analysis of nonmonetary rewards....

Adaptive pixel-to-pixel projection intensity adjustment for measuring a shiny surface using orthogonal color fringe pattern projection

Science.gov (United States)

Chen, Chao; Gao, Nan; Wang, Xiangjun; Zhang, Zonghua

2018-05-01

Three-dimensional (3D) shape measurement based on fringe pattern projection techniques has been commonly used in various fields. One of the remaining challenges in fringe pattern projection is that camera sensor saturation may occur if there is a large range of reflectivity variation across the surface that causes measurement errors. To overcome this problem, a novel fringe pattern projection method is proposed to avoid image saturation and maintain high-intensity modulation for measuring shiny surfaces by adaptively adjusting the pixel-to-pixel projection intensity according to the surface reflectivity. First, three sets of orthogonal color fringe patterns and a sequence of uniform gray-level patterns with different gray levels are projected onto a measured surface by a projector. The patterns are deformed with respect to the object surface and captured by a camera from a different viewpoint. Subsequently, the optimal projection intensity at each pixel is determined by fusing different gray levels and transforming the camera pixel coordinate system into the projector pixel coordinate system. Finally, the adapted fringe patterns are created and used for 3D shape measurement. Experimental results on a flat checkerboard and shiny objects demonstrate that the proposed method can measure shiny surfaces with high accuracy.

Effects of diotic fringes on interaural disparity detection (L)

DEFF Research Database (Denmark)

Le Goff, Nicolas; Kohlrausch, Armin; Dau, Torsten

2012-01-01

Detection thresholds were measured for interaural time differences (ITDs) and interaural level differences (ILDs) that were carried by probe segments embedded in otherwise diotic broadband noise (fringe). The duration of the probe was varied between 5 and 200 ms, and the duration of the fringe...... was between 5 and 100 ms. Consistent with results of Akeroyd and Bernstein [(2001). J. Acoust. Soc. Am. 110, 2516-2526], it was found that a 5-ms fringe placed before a 5-ms probe (forward fringe) led to a larger threshold elevation than a 5-ms fringe placed after the probe (backward fringe). As suggested...... by Akeroyd and Bernstein, this effect was accounted for by a model providing an onset emphasis of a factor of 2. In contrast, for longer probe and fringe durations, which have not been tested before, a backward fringe had a stronger effect than a forward fringe. This surprising effect was accounted...

Non-spectroscopic surface plasmon sensor with a tunable sensitivity

International Nuclear Information System (INIS)

Wen, Qiuling; Han, Xu; Hu, Chuang; Zhang, Jiasen

2015-01-01

We demonstrate a non-spectroscopic surface plasmon sensor with a tunable sensitivity which is based on the relationship between the wave number of surface plasmon polaritons (SPPs) on metal film and the refractive index of the specimen in contact with the metal film. A change in the wave number of the SPPs results in a variation in the propagation angle of the leakage radiation of the SPPs. A reference light is used to interfere with the leakage radiation, and the refractive index of the specimen can be obtained by measuring the period of the interference fringes. The sensitivity of the sensor can be tuned by changing the incident direction of the reference light and this cannot be realized by conventional surface plasmon sensors. For a reference angle of 1.007°, the sensitivity and resolution of the sensor are 4629 μm/RIU (RIU stands for refractive index unit) and 3.6 × 10 −4 RIU, respectively. In addition, the sensor only needs a monochromatic light source, which simplifies the measurement setup and reduces the cost

29 CFR 4.52 - Fringe benefit determinations.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Fringe benefit determinations. 4.52 Section 4.52 Labor... Procedures § 4.52 Fringe benefit determinations. (a) Wage determinations issued pursuant to the Service... differential, which are considered wages rather than fringe benefits under SCA). Pursuant to Section 4(b) of...

7 CFR 15a.56 - Fringe benefits.

Science.gov (United States)

2010-01-01

... 7 Agriculture 1 2010-01-01 2010-01-01 false Fringe benefits. 15a.56 Section 15a.56 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM... Activities Prohibited § 15a.56 Fringe benefits. (a) “Fringe benefits” defined. For purposes of this part...

Fiber optic pH sensor with self-assembled polymer multilayer nanocoatings.

Science.gov (United States)

Shao, Li-Yang; Yin, Ming-Jie; Tam, Hwa-Yaw; Albert, Jacques

2013-01-24

A fiber-optic pH sensor based on a tilted fiber Bragg grating (TFBG) with electrostatic self-assembly multilayer sensing film is presented. The pH sensitive polymeric film, poly(diallyldimethylammonium chloride) (PDDA) and poly(acrylic acid) (PAA) was deposited on the circumference of the TFBG with the layer-by-layer (LbL) electrostatic self-assembly technique. The PDDA/PAA film exhibits a reduction in refractive index by swelling in different pH solutions. This effect results in wavelength shifts and transmission changes in the spectrum of the TFBG. The peak amplitude of the dominant spectral fringes over a certain window of the transmission spectrum, obtained by FFT analysis, has a near-linear pH sensitivity of 117 arbitrary unit (a.u.)/pH unit and an accuracy of ±1 a.u. (in the range of pH 4.66 to pH 6.02). The thickness and surface morphology of the sensing multilayer film were characterized to investigate their effects on the sensor's performance. The dynamic response of the sensor also has been studied (10 s rise time and 18 s fall time for a sensor with six bilayers of PDDA/PAA).

15 CFR 8a.525 - Fringe benefits.

Science.gov (United States)

2010-01-01

... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Fringe benefits. 8a.525 Section 8a.525 Commerce and Foreign Trade Office of the Secretary of Commerce NONDISCRIMINATION ON THE BASIS OF SEX IN... in Employment in Education Programs or Activities Prohibited § 8a.525 Fringe benefits. (a) “Fringe...

Investigation of michelson interferometer for volatile organic compound sensor

International Nuclear Information System (INIS)

Marzuarman; Rivai, Muhammad; Sardjono, Tri Arief; Purwanto, Djoko

2017-01-01

The sensor device is required to monitor harmful gases in the environments and industries. Many volatile organic compounds adsorbed on the sensor material will result in changes of the optical properties including the refractive index and the film thickness. This study designed and realized a vapor detection device using the principle of Michelson Interferometer. The laser light beamed with a wavelength of 620 nm was divided by using a beam splitter. Interference occurredwhen the two separated lights were recombined. The phase difference between the two beams determined whether the interference would destruct or construct each other to produce the curved fringes. The vapor samples used in these experiments were ethanol and benzene. The results showed that the ethanol concentration of 1611-32210 ppm produced a fringe shift of 197 pixels, while the concentration of benzene of 964-19290 ppm produced a fringe shift of 273 pixels. (paper)

Windowed fringe pattern analyis

CERN Document Server

Kemao, Qian

2013-01-01

This book provides solutions to the challenges involved in fringe pattern analysis, covering techniques for full-field, noncontact, and high-sensitivity measurement. The primary goal of fringe pattern analysis is to extract the hidden phase distributions that generally relate to the physical quantities being measured. Both theoretical analysis and algorithm development are covered to facilitate the work of researchers and engineers. The information presented is also appropriate as a specialized subject for students of optical and computer engineering.

Robust Fringe Projection Profilometry via Sparse Representation.

Science.gov (United States)

Budianto; Lun, Daniel P K

2016-04-01

In this paper, a robust fringe projection profilometry (FPP) algorithm using the sparse dictionary learning and sparse coding techniques is proposed. When reconstructing the 3D model of objects, traditional FPP systems often fail to perform if the captured fringe images have a complex scene, such as having multiple and occluded objects. It introduces great difficulty to the phase unwrapping process of an FPP system that can result in serious distortion in the final reconstructed 3D model. For the proposed algorithm, it encodes the period order information, which is essential to phase unwrapping, into some texture patterns and embeds them to the projected fringe patterns. When the encoded fringe image is captured, a modified morphological component analysis and a sparse classification procedure are performed to decode and identify the embedded period order information. It is then used to assist the phase unwrapping process to deal with the different artifacts in the fringe images. Experimental results show that the proposed algorithm can significantly improve the robustness of an FPP system. It performs equally well no matter the fringe images have a simple or complex scene, or are affected due to the ambient lighting of the working environment.

LineVISAR. A fringe-trace data analysis program

Energy Technology Data Exchange (ETDEWEB)

Furnish, Michael D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2014-02-01

The line-imaging ORVIS or VISAR provides velocity as a function of position and time for a line on an experimental setup via a streak camera record of interference fringes. This document describes a Matlab-based program which guides the user through the process of converting these fringe data to a velocity surface. The data reduction is of the "fringe trace" type, wherein the changes in velocity at a given position on the line are calculated based on fringe motion past that point. The analyst must establish the fringe behavior up front, aided by peak-finding routines in the program. However, the later work of using fringe jumps to compensate for phase problems in other analysis techniques is greatly reduced. This program is not a standard GUI construction, and is prescriptive. At various points it saves the progress, allowing later restarts from those points.

Optimized Beam Sculpting with Generalized Fringe-rate Filters

Science.gov (United States)

Parsons, Aaron R.; Liu, Adrian; Ali, Zaki S.; Cheng, Carina

2016-03-01

We generalize the technique of fringe-rate filtering, whereby visibilities measured by a radio interferometer are re-weighted according to their temporal variation. As the Earth rotates, radio sources traverse through an interferometer’s fringe pattern at rates that depend on their position on the sky. Capitalizing on this geometric interpretation of fringe rates, we employ time-domain convolution kernels to enact fringe-rate filters that sculpt the effective primary beam of antennas in an interferometer. As we show, beam sculpting through fringe-rate filtering can be used to optimize measurements for a variety of applications, including mapmaking, minimizing polarization leakage, suppressing instrumental systematics, and enhancing the sensitivity of power-spectrum measurements. We show that fringe-rate filtering arises naturally in minimum variance treatments of many of these problems, enabling optimal visibility-based approaches to analyses of interferometric data that avoid systematics potentially introduced by traditional approaches such as imaging. Our techniques have recently been demonstrated in Ali et al., where new upper limits were placed on the 21 {cm} power spectrum from reionization, showcasing the ability of fringe-rate filtering to successfully boost sensitivity and reduce the impact of systematics in deep observations.

INTERFERENCE FRINGES OF SOLAR ACOUSTIC WAVES AROUND SUNSPOTS

Energy Technology Data Exchange (ETDEWEB)

Chou, Dean-Yi; Zhao Hui; Yang, Ming-Hsu; Liang, Zhi-Chao, E-mail: chou@phys.nthu.edu.tw [Physics Department, National Tsing Hua University, Hsinchu, Taiwan (China)

2012-10-20

Solar acoustic waves are scattered by a sunspot due to the interaction between the acoustic waves and the sunspot. The sunspot, excited by the incident wave, generates the scattered wave. The scattered wave is added to the incident wave to form the total wave around the sunspot. The interference fringes between the scattered wave and the incident wave are visible in the intensity of the total wave because the coherent time of the incident wave is of the order of a wave period. The strength of the interference fringes anti-correlates with the width of temporal spectra of the incident wave. The separation between neighboring fringes increases with the incident wavelength and the sunspot size. The strength of the fringes increases with the radial order n of the incident wave from n = 0 to n = 2, and then decreases from n = 2 to n = 5. The interference fringes play a role analogous to holograms in optics. This study suggests the feasibility of using the interference fringes to reconstruct the scattered wavefields of the sunspot, although the quality of the reconstructed wavefields is sensitive to the noise and errors in the interference fringes.

Fringing field measurement of dipole magnet

International Nuclear Information System (INIS)

Lu Hongyou; Jiang Weisheng; Mao Naifeng; Mao Xingwang

1985-01-01

The fringing field of a dipole magnet with a C-type circuit and homogeneous field in the gap has been measured including the distributions of fringing fields with and without magnetic shield. The measured data was analyzed by using the concept of virtual field boundary

Does Gender Influence the Provision of Fringe Benefits?

DEFF Research Database (Denmark)

Rand, John; Tarp, Finn

2011-01-01

This contribution studies the provision of fringe benefits using a unique survey of small and medium-sized enterprises (SMEs) in Vietnam. Analysis of the survey reveals that women who own SMEs are more likely than men who own similar firms to provide employees with fringe benefits such as annual...... and workforce structure, worker recruitment mechanisms, and the degree of unionization. However, these factors cannot fully account for the observed differences in fringe benefits along the “gender of owner” dimension. There remains a sizable and unexplained fringe benefits premium paid to employees in women...

Carrier introduction to moire pattern for automatic fringe-order distinguishing

International Nuclear Information System (INIS)

Fang, J.; Laermann, K.H.

1992-01-01

This paper presents an automatic procedure of pseudo-colour encoding of moire fringe orders. A carrier consisting of parallel fringes is introduced before the specimen deforms. The carrier pattern is captured by a camera and then stored in computer as a standard image. The space of the carrier fringes is distored by the strains on the specimen as it is loaded. On a certain condition, the orders of the frequency-modulated carrier still vary monotonically so that they can be easyly distinguished. Both the standard fringe-carrier and the frequency-modulated fringe pattern are transformed into two digital images, of which every fringe is encoded by one of the pseudo-colour codes corresponding to the monotonical fringe orders. At each pixel, the difference between the colour sequences of two images is calculated to obtain the fringe order of pure deformation. The moire pattern of the in-plane displacement is restored as a pseudo-colour image by whose colour-change the variation of the fringe orders is displayed. (orig.)

Colloid mobilization and transport during capillary fringe fluctuations.

Science.gov (United States)

Aramrak, Surachet; Flury, Markus; Harsh, James B; Zollars, Richard L

2014-07-01

Capillary fringe fluctuations due to changing water tables lead to displacement of air-water interfaces in soils and sediments. These moving air-water interfaces can mobilize colloids. We visualized colloids interacting with moving air-water interfaces during capillary fringe fluctuations by confocal microscopy. We simulated capillary fringe fluctuations in a glass-bead-filled column. We studied four specific conditions: (1) colloids suspended in the aqueous phase, (2) colloids attached to the glass beads in an initially wet porous medium, (3) colloids attached to the glass beads in an initially dry porous medium, and (4) colloids suspended in the aqueous phase with the presence of a static air bubble. Confocal images confirmed that the capillary fringe fluctuations affect colloid transport behavior. Hydrophilic negatively charged colloids initially suspended in the aqueous phase were deposited at the solid-water interface after a drainage passage, but then were removed by subsequent capillary fringe fluctuations. The colloids that were initially attached to the wet or dry glass bead surface were detached by moving air-water interfaces in the capillary fringe. Hydrophilic negatively charged colloids did not attach to static air-bubbles, but hydrophobic negatively charged and hydrophilic positively charged colloids did. Our results demonstrate that capillary fringe fluctuations are an effective means for colloid mobilization.

Assessing increasing susceptibility to wildfire at the wildland-urban fringe in the western United States

Science.gov (United States)

Kinoshita, A. M.; Hogue, T. S.

2013-05-01

Much of the western U.S. is increasingly susceptible to wildfire activity due to drier conditions, elevated fuel loads, and expanding urbanization. As population increases, development pushes the urban boundary further into wildlands, creating more potential for human interaction at the wildland-urban interface (WUI), primarily from human ignitions and fire suppression policies. The immediate impacts of wildfires include vulnerability to debris flows, flooding, and impaired water quality. Fires also alter longer-term hydrological and ecosystem behavior. The current study utilizes geospatial datasets to investigate historical wildfire size and frequency relative to the WUI for a range of cities across western North America. California, the most populous state in the U.S., has an extensive fire history. The decennial population and acres burned for four major counties (Los Angeles, San Bernardino, San Diego, and Shasta) in California show that increasing wildfire size and frequency follow urbanization trends, with high correlation between the last decade of burned area, urban-fringe proximity, and increasing population. Ultimately, results will provide information on urban fringe communities that are most vulnerable to the risks associated with wildfire and post-fire impacts. In light of evolving land use policies (i.e. forest management and treatment, development at the urban-fringe) and climate change, it is critical to advance our knowledge of the implications that these conditions pose to urban centers, communicate risks to the public, and ultimately provide guidance for wildfire management.

26 CFR 1.132-9 - Qualified transportation fringes.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Qualified transportation fringes. 1.132-9... Qualified transportation fringes. (a) Table of contents. This section contains a list of the questions and answers in § 1.132-9. (1) General rules. Q-1. What is a qualified transportation fringe? Q-2. What is...

Fringe counting method for synthetic phase with frequency-modulated laser diodes

International Nuclear Information System (INIS)

Onodera, Ribun; Sakuyama, Munechika; Ishii, Yukihiro

2007-01-01

Fringe counting method with laser diodes (LDs) for displacement measurement has been constructed. Two LDs are frequency modulated by mutually inverted sawtooth currents on an unbalanced two-beam interferometer. The mutually inverted sawtooth-current modulation of LDs produces interference fringe signals with opposite signs for respective wavelengths. The two fringe signals are fed to an electronic mixer to produce a synthetic fringe signal with a reduced sensitivity to the synthetic wavelength. Synthetic fringe pulses derived from the synthetic fringe signal make a fringe counting system possible for faster movement of the tested mirror

77 FR 42419 - Airworthiness Directives; Honeywell International, Inc. Global Navigation Satellite Sensor Units

Science.gov (United States)

2012-07-19

... Airworthiness Directives; Honeywell International, Inc. Global Navigation Satellite Sensor Units AGENCY: Federal.... Model KGS200 Mercury\\2\\ wide area augmentation system (WAAS) global navigation satellite sensor units... similar Honeywell global positioning system (GPS) sensor and the same software as the Model KGS200 Mercury...

High-frequency background modulation fringe patterns based on a fringe-wavelength geometry-constraint model for 3D surface-shape measurement.

Science.gov (United States)

Liu, Xinran; Kofman, Jonathan

2017-07-10

A new fringe projection method for surface-shape measurement was developed using four high-frequency phase-shifted background modulation fringe patterns. The pattern frequency is determined using a new fringe-wavelength geometry-constraint model that allows only two corresponding-point candidates in the measurement volume. The correct corresponding point is selected with high reliability using a binary pattern computed from intensity background encoded in the fringe patterns. Equations of geometry-constraint parameters permit parameter calculation prior to measurement, thus reducing measurement computational cost. Experiments demonstrated the ability of the method to perform 3D shape measurement for a surface with geometric discontinuity, and for spatially isolated objects.

Fringe instability in constrained soft elastic layers.

Science.gov (United States)

Lin, Shaoting; Cohen, Tal; Zhang, Teng; Yuk, Hyunwoo; Abeyaratne, Rohan; Zhao, Xuanhe

2016-11-04

Soft elastic layers with top and bottom surfaces adhered to rigid bodies are abundant in biological organisms and engineering applications. As the rigid bodies are pulled apart, the stressed layer can exhibit various modes of mechanical instabilities. In cases where the layer's thickness is much smaller than its length and width, the dominant modes that have been studied are the cavitation, interfacial and fingering instabilities. Here we report a new mode of instability which emerges if the thickness of the constrained elastic layer is comparable to or smaller than its width. In this case, the middle portion along the layer's thickness elongates nearly uniformly while the constrained fringe portions of the layer deform nonuniformly. When the applied stretch reaches a critical value, the exposed free surfaces of the fringe portions begin to undulate periodically without debonding from the rigid bodies, giving the fringe instability. We use experiments, theory and numerical simulations to quantitatively explain the fringe instability and derive scaling laws for its critical stress, critical strain and wavelength. We show that in a force controlled setting the elastic fingering instability is associated with a snap-through buckling that does not exist for the fringe instability. The discovery of the fringe instability will not only advance the understanding of mechanical instabilities in soft materials but also have implications for biological and engineered adhesives and joints.

Optical fringe-reflection deflectometry with bundle adjustment

Science.gov (United States)

Xiao, Yong-Liang; Li, Sikun; Zhang, Qican; Zhong, Jianxin; Su, Xianyu; You, Zhisheng

2018-06-01

Liquid crystal display (LCD) screens are located outside of a camera's field of view in fringe-reflection deflectometry. Therefore, fringes that are displayed on LCD screens are obtained through specular reflection by a fixed camera. Thus, the pose calibration between the camera and LCD screen is one of the main challenges in fringe-reflection deflectometry. A markerless planar mirror is used to reflect the LCD screen more than three times, and the fringes are mapped into the fixed camera. The geometrical calibration can be accomplished by estimating the pose between the camera and the virtual image of fringes. Considering the relation between their pose, the incidence and reflection rays can be unified in the camera frame, and a forward triangulation intersection can be operated in the camera frame to measure three-dimensional (3D) coordinates of the specular surface. In the final optimization, constraint-bundle adjustment is operated to refine simultaneously the camera intrinsic parameters, including distortion coefficients, estimated geometrical pose between the LCD screen and camera, and 3D coordinates of the specular surface, with the help of the absolute phase collinear constraint. Simulation and experiment results demonstrate that the pose calibration with planar mirror reflection is simple and feasible, and the constraint-bundle adjustment can enhance the 3D coordinate measurement accuracy in fringe-reflection deflectometry.

Automated Fringe Pattern Acquisition for Portable Laser Shearography

International Nuclear Information System (INIS)

Khairiah Yazid; Mohd Yusnisyam Yusof; Wan Saffiey Wan Abdullah

2013-01-01

In shearography system one of the most important tasks is the automatic, fast, reliable processing of the fringe patterns to allow real time inspection. Development of digital CCD cameras, the PC (fast and small data acquisition), high power lasers have led to dramatic performance improvements in shearography instruments and systems. This paper concentrates on development of fringe pattern acquisition using digital CCD camera for portable laser shearography system. A new program for fringe pattern processing which incorporates rapid methods for automatic fringe pattern acquisition and filtering has been developed. The algorithm is written using MATLAB. A graphical user interface with several functions was developed to ensure an easy adaptation in custom applications and providing a flexible way for additional functions. The preliminary results show that the developed algorithm can be used to generate good contrast and reliable fringe pattern. (author)

29 CFR 1620.11 - Fringe benefits.

Science.gov (United States)

2010-07-01

... Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION THE EQUAL PAY ACT § 1620.11 Fringe... unlawful for an employer to discriminate between men and women performing equal work with regard to fringe... spouses or families of employees of one gender where the same benefits are not made available for the...

Manic fringe is not required for embryonic development, and fringe family members do not exhibit redundant functions in the axial skeleton, limb, or hindbrain

Science.gov (United States)

Moran, Jennifer L.; Shifley, Emily T.; Levorse, John M.; Mani, Shyamala; Ostmann, Kristin; Perez-Balaguer, Ariadna; Walker, Dawn M.; Vogt, Thomas F.; Cole, Susan E.

2009-01-01

Tight regulation of Notch pathway signaling is important in many aspects of embryonic development. Notch signaling can be modulated by expression of fringe genes, encoding glycosyltransferases that modify EGF repeats in the Notch receptor. Although Lunatic fringe (Lfng) has been shown to play important roles in vertebrate segmentation, comparatively little is known regarding the developmental functions of the other vertebrate fringe genes, Radical fringe (Rfng) and Manic fringe (Mfng). Here we report that Mfng expression is not required for embryonic development. Further, we find that despite significant overlap in expression patterns, we detect no obvious synergistic defects in mice in the absence of two, or all three, fringe genes during development of the axial skeleton, limbs, hindbrain and cranial nerves. PMID:19479951

Towards accurate simulation of fringe field effects

International Nuclear Information System (INIS)

Berz, M.; Erdelyi, B.; Makino, K.

2001-01-01

In this paper, we study various fringe field effects. Previously, we showed the large impact that fringe fields can have on certain lattice scenarios of the proposed Neutrino Factory. Besides the linear design of the lattice, the effects depend strongly on the details of the field fall off. Various scenarios are compared. Furthermore, in the absence of detailed information, we study the effects for the LHC, a case where the fringe fields are known, and try to draw some conclusions for Neutrino Factory lattices

Accuracy and high-speed technique for autoprocessing of Young's fringes

Science.gov (United States)

Chen, Wenyi; Tan, Yushan

1991-12-01

In this paper, an accurate and high-speed method for auto-processing of Young's fringes is proposed. A group of 1-D sampled intensity values along three or more different directions are taken from Young's fringes, and the fringe spacings of each direction are obtained by 1-D FFT respectively. Two directions that have smaller fringe spacing are selected from all directions. The accurate fringe spacings along these two directions are obtained by using orthogonal coherent phase detection technique (OCPD). The actual spacing and angle of Young's fringes, therefore, can be calculated. In this paper, the principle of OCPD is introduced in detail. The accuracy of the method is evaluated theoretically and experimentally.

An Asynchronous Multi-Sensor Micro Control Unit for Wireless Body Sensor Networks (WBSNs

Directory of Open Access Journals (Sweden)

Ching-Hsing Luo

2011-07-01

Full Text Available In this work, an asynchronous multi-sensor micro control unit (MCU core is proposed for wireless body sensor networks (WBSNs. It consists of asynchronous interfaces, a power management unit, a multi-sensor controller, a data encoder (DE, and an error correct coder (ECC. To improve the system performance and expansion abilities, the asynchronous interface is created for handshaking different clock domains between ADC and RF with MCU. To increase the use time of the WBSN system, a power management technique is developed for reducing power consumption. In addition, the multi-sensor controller is designed for detecting various biomedical signals. To prevent loss error from wireless transmission, use of an error correct coding technique is important in biomedical applications. The data encoder is added for lossless compression of various biomedical signals with a compression ratio of almost three. This design is successfully tested on a FPGA board. The VLSI architecture of this work contains 2.68-K gate counts and consumes power 496-μW at 133-MHz processing rate by using TSMC 0.13-μm CMOS process. Compared with the previous techniques, this work offers higher performance, more functions, and lower hardware cost than other micro controller designs.

26 CFR 1.132-8 - Fringe benefit nondiscrimination rules.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Fringe benefit nondiscrimination rules. 1.132-8... Fringe benefit nondiscrimination rules. (a) Application of nondiscrimination rules—(1) General rule. A.... (2) Consequences of discrimination—(i) In general. If an employer maintains more than one fringe...

Computer aided fringe pattern analysis

Science.gov (United States)

Sciammarella, Cesar A.

The paper reviews the basic laws of fringe pattern interpretation. The different techniques that are currently utilized are presented using a common frame of reference stressing the fact that these techniques are different variations of the same basic principle. Digital and analog techniques are discussed. Currently available hardware is presented and the relationships between hardware and the operations of pattern fringe processing are pointed out. Examples are given to illustrate the ideas discussed in the paper.

Effect of low-frequency vibrations on speckle interferometry fringes

International Nuclear Information System (INIS)

Vikram, C.S.; Pechersky, M.J.

1998-01-01

The effects of low-frequency vibrations on speckle correlation fringes have been investigated. The relatively short capture time of the camera in the low-frequency case may yield usable fringe contrast in spite of vibration. It has been shown that the fringes also shift due to the vibration. The study is in agreement with experimental observations of good-contrast correlation fringes even if the object is not on a vibration-isolated table. Some such experimental observations are also presented. copyright 1998 Society of Photo-Optical Instrumentation Engineers

Strong time-consistency in the cartel-versus-fringe model

NARCIS (Netherlands)

Groot, F.; Withagen, C.A.A.M.; Zeeuw, de A.J.

2003-01-01

Due to developments on the oil market in the 1970s, the theory of exhaustible resources was extended with the cartel-versus-fringe model to characterize markets with one big coherent cartel and a large number of small suppliers called the fringe. Because cartel and fringe are leader and follower,

29 CFR 4.170 - Furnishing fringe benefits or equivalents.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Furnishing fringe benefits or equivalents. 4.170 Section 4... Standards Compliance with Compensation Standards § 4.170 Furnishing fringe benefits or equivalents. (a) General. Fringe benefits required under the Act shall be furnished, separate from and in addition to the...

Improved Spectral Resolution of Long-Period Fiber Grating Sensors for Ultra-High Temperature Environments Using Narrow Interferences between Regenerated Gratings

DEFF Research Database (Denmark)

Kristensen, Martin; Russell, J; Gao, Shaorui

2014-01-01

The advantages of D-shape fiber in combination with an optical analog of Ramsey fringes using LPGs are presented. The mode-profiles of the sensor were characterized experimentally to provide deeper knowledge about improved functionality.......The advantages of D-shape fiber in combination with an optical analog of Ramsey fringes using LPGs are presented. The mode-profiles of the sensor were characterized experimentally to provide deeper knowledge about improved functionality....

Phase retrieval from reflective fringe patterns of double-sided transparent objects

International Nuclear Information System (INIS)

Huang, Lei; Asundi, Anand Krishna

2012-01-01

‘Ghosted’ fringe patterns simultaneously reflected from both the upper and lower sides of a transparent target in the fringe reflection technique are captured for transparent surface 3D shape measurement, but the phase retrieval from the captured ‘ghosted’ fringe patterns is still not solved. A novel method is proposed to solve this issue by using two sets of phase-shifted fringe patterns with slightly different frequencies. The nonlinear least-squares method is used to estimate the fringe phase and modulation from both front and rear interfaces. Several simulations are done to show the feasibility of the proposed method. The influence of fringe noise on the algorithm is studied as well, which indicates that the proposed method is able to retrieve the phase from double-sided reflective fringe patterns with fringe noise equivalent to that in practical measurements. The merits and limitations of the method are discussed and recommendations for future studies are made. (paper)

26 CFR 1.61-21 - Taxation of fringe benefits.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Taxation of fringe benefits. 1.61-21 Section 1... § 1.61-21 Taxation of fringe benefits. (a) Fringe benefits—(1) In general. Section 61(a)(1) provides... vehicle. The fact that another section of subtitle A of the Internal Revenue Code addresses the taxation...

29 CFR 5.25 - Rate of contribution or cost for fringe benefits.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Rate of contribution or cost for fringe benefits. 5.25... Fringe Benefits Provisions of the Davis-Bacon Act § 5.25 Rate of contribution or cost for fringe benefits... contribution or cost of fringe benefits. Only the amount of contributions or costs for fringe benefits which...

Inpainting for Fringe Projection Profilometry Based on Geometrically Guided Iterative Regularization.

Science.gov (United States)

Budianto; Lun, Daniel P K

2015-12-01

Conventional fringe projection profilometry methods often have difficulty in reconstructing the 3D model of objects when the fringe images have the so-called highlight regions due to strong illumination from nearby light sources. Within a highlight region, the fringe pattern is often overwhelmed by the strong reflected light. Thus, the 3D information of the object, which is originally embedded in the fringe pattern, can no longer be retrieved. In this paper, a novel inpainting algorithm is proposed to restore the fringe images in the presence of highlights. The proposed method first detects the highlight regions based on a Gaussian mixture model. Then, a geometric sketch of the missing fringes is made and used as the initial guess of an iterative regularization procedure for regenerating the missing fringes. The simulation and experimental results show that the proposed algorithm can accurately reconstruct the 3D model of objects even when their fringe images have large highlight regions. It significantly outperforms the traditional approaches in both quantitative and qualitative evaluations.

Corneal topometry by fringe projection: limits and possibilities

Science.gov (United States)

Windecker, Robert; Tiziani, Hans J.; Thiel, H.; Jean, Benedikt J.

1996-01-01

A fast and accurate measurement of corneal topography is an important task especially since laser induced corneal reshaping has been used for the correction of ametropia. The classical measuring system uses Placido rings for the measurement and calculation of the topography or local curvatures. Another approach is the projection of a known fringe map to be imaged onto the surface under a certain angle of incidence. We present a set-up using telecentric illumination and detection units. With a special grating we get a synthetic wavelength with a nearly sinusoidal profile. In combination with a very fast data acquisition the topography can be evaluated using as special selfnormalizing phase evaluation algorithm. It calculates local Fourier coefficients and corrects errors caused by imperfect illumination or inhomogeneous scattering by fringe normalization. The topography can be determined over 700 by 256 pixel. The set-up is suitable to measure optically rough silicon replica of the human cornea as well as the cornea in vivo over a field of 8 mm and more. The resolution is mainly limited by noise and is better than two micrometers. We discuss the principle benefits and the drawbacks compared with standard Placido technique.

Micro analysis of fringe field formed inside LDA measuring volume

International Nuclear Information System (INIS)

Ghosh, Abhijit; Nirala, A K

2016-01-01

In the present study we propose a technique for micro analysis of fringe field formed inside laser Doppler anemometry (LDA) measuring volume. Detailed knowledge of the fringe field obtained by this technique allows beam quality, alignment and fringe uniformity to be evaluated with greater precision and may be helpful for selection of an appropriate optical element for LDA system operation. A complete characterization of fringes formed at the measurement volume using conventional, as well as holographic optical elements, is presented. Results indicate the qualitative, as well as quantitative, improvement of fringes formed at the measurement volume by holographic optical elements. Hence, use of holographic optical elements in LDA systems may be advantageous for improving accuracy in the measurement. (paper)

29 CFR 4.174 - Meeting requirements for holiday fringe benefits.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Meeting requirements for holiday fringe benefits. 4.174... Compensation Standards Compliance with Compensation Standards § 4.174 Meeting requirements for holiday fringe benefits. (a) Determining eligibility for holiday benefits—in general. (1) Most fringe benefit...

Note: Optical fiber milled by focused ion beam and its application for Fabry-Pérot refractive index sensor

DEFF Research Database (Denmark)

Yuan, Scott Wu; Wang, Fei; Savenko, Alexey

2011-01-01

We introduce a highly compact fiber-optic Fabry-Pérot refractive index sensor integrated with a fluid channel that is fabricated directly near the tip of a 32 μm in diameter single-mode fiber taper. The focused ion beam technique is used to efficiently mill the microcavity from the fiber side...... and finely polish the end facets of the cavity with a high spatial resolution. It is found that a fringe visibility of over 15 dB can be achieved and that the sensor has a sensitivity of ∼1731 nm/RIU (refractive index units) and a detection limit of ∼5.78 × 10−6 RIU. This miniature integrated all-in-fiber...

Determination of Stress Intensity Factor K1 from Two Fringe Orders by Fringe Multiplication and Sharpening

International Nuclear Information System (INIS)

Chen, Lei; Baek, Tae Hyun

2007-01-01

Stress intensity factor is one of the most important parameters in fracture mechanics. Both the stress field distribution and the crack propagation are closely related to these parameters. Due to the complexity of actual engineering problems, it is difficult to calculate the stress intensity factor by theoretical formulation, so photoelasticity method is a good choice. In this paper, modified two parameter method is employed to calculate stress intensity factor for opening mode by using data from more than one photoelastic fringe loop. For getting accurate experiment results, the initial fringes are doubled and sharpened by digital image programs from the fringe patterns obtained by a CCD camera. Photoelastic results are compared with those obtained by the use of empirical equation and FEM. Good agreement shows that the methods utilized in experiments are considerably reliable. The photoelastic experiment can be used for bench mark in theoretical study and other experiments

Fringe-projection profilometry based on two-dimensional empirical mode decomposition.

Science.gov (United States)

Zheng, Suzhen; Cao, Yiping

2013-11-01

In 3D shape measurement, because deformed fringes often contain low-frequency information degraded with random noise and background intensity information, a new fringe-projection profilometry is proposed based on 2D empirical mode decomposition (2D-EMD). The fringe pattern is first decomposed into numbers of intrinsic mode functions by 2D-EMD. Because the method has partial noise reduction, the background components can be removed to obtain the fundamental components needed to perform Hilbert transformation to retrieve the phase information. The 2D-EMD can effectively extract the modulation phase of a single direction fringe and an inclined fringe pattern because it is a full 2D analysis method and considers the relationship between adjacent lines of a fringe patterns. In addition, as the method does not add noise repeatedly, as does ensemble EMD, the data processing time is shortened. Computer simulations and experiments prove the feasibility of this method.

Comparative analysis on some spatial-domain filters for fringe pattern denoising.

Science.gov (United States)

Wang, Haixia; Kemao, Qian

2011-04-20

Fringe patterns produced by various optical interferometric techniques encode information such as shape, deformation, and refractive index. Noise affects further processing of the fringe patterns. Denoising is often needed before fringe pattern demodulation. Filtering along the fringe orientation is an effective option. Such filters include coherence enhancing diffusion, spin filtering with curve windows, second-order oriented partial-differential equations, and the regularized quadratic cost function for oriented fringe pattern filtering. These filters are analyzed to establish the relationships among them. Theoretical analysis shows that the four filters are largely equivalent to each other. Quantitative results are given on simulated fringe patterns to validate the theoretical analysis and to compare the performance of these filters. © 2011 Optical Society of America

Time average vibration fringe analysis using Hilbert transformation

International Nuclear Information System (INIS)

Kumar, Upputuri Paul; Mohan, Nandigana Krishna; Kothiyal, Mahendra Prasad

2010-01-01

Quantitative phase information from a single interferogram can be obtained using the Hilbert transform (HT). We have applied the HT method for quantitative evaluation of Bessel fringes obtained in time average TV holography. The method requires only one fringe pattern for the extraction of vibration amplitude and reduces the complexity in quantifying the data experienced in the time average reference bias modulation method, which uses multiple fringe frames. The technique is demonstrated for the measurement of out-of-plane vibration amplitude on a small scale specimen using a time average microscopic TV holography system.

Study of moire fringes using synchrotron X-rays

International Nuclear Information System (INIS)

Yoshimura, Jun-ichi

1992-01-01

It has recently been shown that X-ray moire fringes are not exactly the projection of the intensity distribution of the wave field on the exit surface of the crystal, but do oscillate along the beam path behind the crystal. Such nonprojectiveness of moire fringes is inexplicable by the conventional understanding of moire fringes, and therefore is of interest from a fundamental viewpoint as well as practical one. In this paper the phenomena of the nonprojectiveness are described on the basis of the latest experimental data obtained by synchrotron radiation. (author)

Separation of complex fringe patterns using two-dimensional continuous wavelet transform.

Science.gov (United States)

Pokorski, Krzysztof; Patorski, Krzysztof

2012-12-10

A method for processing fringe patterns containing additively superimposed multiple fringe sets is presented. It enables to analyze different fringe families present in a single image separately. The proposed method is based on a two-dimensional continuous wavelet transform. A robust ridge extraction algorithm for a single fringe set extraction is presented. The method is fully automatic and requires no user interference. Spectral separation of fringe families is not required. Simulations are presented to verify performance and advantage of the proposed method over the Fourier transform based technique. Method validity has been confirmed using experimental images.

11 CFR 114.12 - Incorporation of political committees; payment of fringe benefits.

Science.gov (United States)

2010-01-01

... of fringe benefits. 114.12 Section 114.12 Federal Elections FEDERAL ELECTION COMMISSION GENERAL CORPORATE AND LABOR ORGANIZATION ACTIVITY § 114.12 Incorporation of political committees; payment of fringe...'s share of the cost of fringe benefits, such as health and life insurance and retirement, for...

In-phase and anti-phase interference fringes in Laue case

International Nuclear Information System (INIS)

Negishi, Riichirou; Fukamachi, Tomoe; Yoshizawa, Masami; Hirano, Kenji; Hirano, Keiichi; Kawamura, Takaaki

2009-01-01

By using X-rays from synchrotron radiation, we measured the rocking curves due to only the imaginary part of the atomic scattering factor in Laue case. The interference fringes are observed which are totally different from the Pendelloesung fringe. The fringes of the diffracted and transmitted rocking curves are in-phase with each other. We studied the origin of the in-phase fringes by using the complex dispersion surface and the electric field in the crystal, and also the relation with a coupled pendulum. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

29 CFR 4.172 - Meeting requirements for particular fringe benefits-in general.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Meeting requirements for particular fringe benefits-in... particular fringe benefits—in general. Where a fringe benefit determination specifies the amount of the..., as such costs are properly a business expense of the employer. If prevailing fringe benefits for...

In Situ Fringe Projection Profilometry for Laser Power Bed Fusion Process

Science.gov (United States)

Zhang, Bin

Additive manufacturing (AM) offers an industrial solution to produce parts with complex geometries and internal structures that conventional manufacturing techniques cannot produce. However, current metal additive process, particularly the laser powder bed fusion (LPBF) process, suffers from poor surface finish and various material defects which hinder its wide applications. One way to solve this problem is by adding in situ metrology sensor onto the machine chamber. Matured manufacturing processes are tightly monitored and controlled, and instrumentation advances are needed to realize this same advantage for metal additive process. This encourages us to develop an in situ fringe projection system for the LPBF process. The development of such a system and the measurement capability are demonstrated in this dissertation. We show that this system can measure various powder bed signatures including powder layer variations, the average height drop between fused metal and unfused powder, and the height variations on the fused surfaces. The ability to measure textured surface is also evaluated through the instrument transfer function (ITF). We analyze the mathematical model of the proposed fringe projection system, and prove the linearity of the system through simulations. A practical ITF measurement technique using a stepped surface is also demonstrated. The measurement results are compared with theoretical predictions generated through the ITF simulations.

Straight, conic and circular fringes in single interferogram

International Nuclear Information System (INIS)

Rajkumar

2015-01-01

Interferometry is an important part of optics courses taught at the undergraduate level in universities throughout the world. It is used to explain to students the wave nature of light and is also used to measure parameters like length, refractive index, thickness of test samples and wavelength of light source, etc. The shape of interference fringes (linear, conic or circular) gives vital information about the interfering wavefronts and is used for firsthand visual inspection in optical shop testing and other applications of scientific and engineering importance. The present work describes a simple laboratory technique to generate fringes with different shapes in a single interferogram. This is achieved by using our diffraction-Lloyd mirror interferometer where two portions of the diffracted field are superimposed to generate the interference fringes. The technique is quite helpful in explaining the role of source orientation on the shape of interference fringes to students. (paper)

14 CFR 93.345 - VFR outbound procedures for fringe airports.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false VFR outbound procedures for fringe airports... Metropolitan Area Special Flight Rules Area § 93.345 VFR outbound procedures for fringe airports. (a) A pilot may depart from a fringe airport as defined in § 93.335 without filing a flight plan or communicating...

Fringe field effects in small rings of large acceptance

Directory of Open Access Journals (Sweden)

Martin Berz

2000-12-01

Full Text Available Recently there has been renewed interest in the influence of fringe fields on particle dynamics, due to studies that revealed their importance in some cases, as, for example, the proposed Neutrino Factory and muon colliders. In this paper, we present a systematic study of generic fringe field effects. Using as an example a lattice of the proposed Neutrino Factory, we show that fringe fields influence the dynamics of particles at all orders, starting with the linear motion. It is found that the widely used sharp cutoff approximation leads to divergences regardless of the specific fall-off shape of the fields. The results suggest that a careful consideration of fringe field effects in the design stage of small machines for large emittances is always recommended.

Measurement uncertainty budget of an interferometric flow velocity sensor

Science.gov (United States)

Bermuske, Mike; Büttner, Lars; Czarske, Jürgen

2017-06-01

Flow rate measurements are a common topic for process monitoring in chemical engineering and food industry. To achieve the requested low uncertainties of 0:1% for flow rate measurements, a precise measurement of the shear layers of such flows is necessary. The Laser Doppler Velocimeter (LDV) is an established method for measuring local flow velocities. For exact estimation of the flow rate, the flow profile in the shear layer is of importance. For standard LDV the axial resolution and therefore the number of measurement points in the shear layer is defined by the length of the measurement volume. A decrease of this length is accompanied by a larger fringe distance variation along the measurement axis which results in a rise of the measurement uncertainty for the flow velocity (uncertainty relation between spatial resolution and velocity uncertainty). As a unique advantage, the laser Doppler profile sensor (LDV-PS) overcomes this problem by using two fan-like fringe systems to obtain the position of the measured particles along the measurement axis and therefore achieve a high spatial resolution while it still offers a low velocity uncertainty. With this technique, the flow rate can be estimated with one order of magnitude lower uncertainty, down to 0:05% statistical uncertainty.1 And flow profiles especially in film flows can be measured more accurately. The problem for this technique is, in contrast to laboratory setups where the system is quite stable, that for industrial applications the sensor needs a reliable and robust traceability to the SI units, meter and second. Small deviations in the calibration can, because of the highly position depending calibration function, cause large systematic errors in the measurement result. Therefore, a simple, stable and accurate tool is needed, that can easily be used in industrial surroundings to check or recalibrate the sensor. In this work, different calibration methods are presented and their influences to the

Vision-based measurement system for structural vibration monitoring using non-projection quasi-interferogram fringe density enhanced by spectrum correction method

International Nuclear Information System (INIS)

Zhong, Jianfeng; Zhong, Shuncong; Zhang, Qiukun; Lu, Huancai; Zhuang, Yizhou; Fu, Xinbin

2017-01-01

A non-projection fringe vision measurement system suitable for vibration monitoring was proposed by using the concept of a 2D optical coherence vibration tomography (2D-OCVT) technique. An artificial quasi-interferogram fringe pattern (QIFP), similar to the interferogram of the 2D-OCVT system, was pasted onto the surface of a vibrating structure as a sensor. Image sequences of the QIFP were captured by a high-speed CMOS camera that worked as a detector. It was possible to obtain both the in-plane and out-of-plane vibration simultaneously. The in-plane vibration was obtained by tracking the center of the imaged QIFP using an image cross-correlation method, whilst the out-of-plane vibration was obtained from the changes in period density of the imaged QIFP. The influence of the noise sources from the CMOS image sensor, together with the effect of the imaging distance, the period density of the QIFP and also the key parameters of the fringe density enhanced by the spectrum correction method on the accuracy of the displacement measurement, were investigated by numerical simulations and experiments. Compared with the results from a conventional accelerometer-based measurement system, the proposed method was demonstrated to be an effective and accurate technique for measuring structural vibration without introducing any extra mass from the accelerometer. The significant advantages of this method include its simple installation and real-time dynamic response measurement capability, making the measurement system ideal for the low- and high-frequency vibration monitoring of engineering structures. (paper)

Virtual fringe projection system with nonparallel illumination based on iteration

International Nuclear Information System (INIS)

Zhou, Duo; Wang, Zhangying; Gao, Nan; Zhang, Zonghua; Jiang, Xiangqian

2017-01-01

Fringe projection profilometry has been widely applied in many fields. To set up an ideal measuring system, a virtual fringe projection technique has been studied to assist in the design of hardware configurations. However, existing virtual fringe projection systems use parallel illumination and have a fixed optical framework. This paper presents a virtual fringe projection system with nonparallel illumination. Using an iterative method to calculate intersection points between rays and reference planes or object surfaces, the proposed system can simulate projected fringe patterns and captured images. A new explicit calibration method has been presented to validate the precision of the system. Simulated results indicate that the proposed iterative method outperforms previous systems. Our virtual system can be applied to error analysis, algorithm optimization, and help operators to find ideal system parameter settings for actual measurements. (paper)

Phase retrieval from a single fringe pattern by using empirical wavelet transform

International Nuclear Information System (INIS)

Guo, Xiaopeng; Zhao, Hong; Wang, Xin

2015-01-01

Phase retrieval from a single fringe pattern is one of the key tasks in optical metrology. In this paper, we present a new method for phase retrieval from a single fringe pattern based on empirical wavelet transform. In the proposed method, a fringe pattern can be effectively divided into three components: nonuniform background, fringes and random noise, which are described in different sub-pass. So the phase distribution information can be robustly extracted from fringes representing a fundamental frequency component. In simulation and a practical projection fringes test, the performance of the present method is successfully verified by comparing with the conventional wavelet transform method in terms of both image quality and phase estimation errors. (paper)

A dual-unit pressure sensor for on-chip self-compensation of zero-point temperature drift

International Nuclear Information System (INIS)

Wang, Jiachou; Li, Xinxin

2014-01-01

A novel dual-unit piezoresistive pressure sensor, consisting of a sensing unit and a dummy unit, is proposed and developed for on-chip self-compensation for zero-point temperature drift. With an MIS (microholes inter-etch and sealing) process implemented only from the front side of single (1 1 1) silicon wafers, a pressure sensitive unit and another identically structured pressure insensitive dummy unit are compactly integrated on-chip to eliminate unbalance factors induced zero-point temperature-drift by mutual compensation between the two units. Besides, both units are physically suspended from silicon substrate to further suppress packaging-stress induced temperature drift. A simultaneously processes ventilation hole-channel structure is connected with the pressure reference cavity of the dummy unit to make it insensitive to detected pressure. In spite of the additional dummy unit, the sensor chip dimensions are still as small as 1.2 mm × 1.2 mm × 0.4 mm. The proposed dual-unit sensor is fabricated and tested, with the tested sensitivity being 0.104 mV kPa −1 3.3 V −1 , nonlinearity of less than 0.08% · FSO and overall accuracy error of ± 0.18% · FSO. Without using any extra compensation method, the sensor features an ultra-low temperature coefficient of offset (TCO) of 0.002% °C −1 · FSO that is much better than the performance of conventional pressure sensors. The highly stable and small-sized sensors are promising for low cost production and applications. (paper)

29 CFR 5.22 - Effect of the Davis-Bacon fringe benefits provisions.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Effect of the Davis-Bacon fringe benefits provisions. 5.22... Fringe Benefits Provisions of the Davis-Bacon Act § 5.22 Effect of the Davis-Bacon fringe benefits... paragraphs (a) and (b) of § 1.2 of this subtitle. The fringe benefits amendments enlarge the scope of this...

Sustainable Urban Fringes - Connecting Urban and Rural : Final report of the SURF project

NARCIS (Netherlands)

Bruijn, de T.J.N.M. (Theo); Haccoû, H.A. (Huib); Leslie, A. (Allison); Lier, G. (Goos); Littlewood, S. (Stephan); Oldejans, R. (Rolf); Thomas, K. (Kevin); Vries, de B.J. (Bauke); Watt, E. (Emma); Wishardt, M. (Michelle)

2012-01-01

What happens at the urban edge and the SURF aspiration to influence it? Projects in the urban fringe Urban fringe governance Integrated policy guidelines and approaches towards urban fringe planning and management The future management of the urban fringe

Modeling aerobic biodegradation in the capillary fringe.

Science.gov (United States)

Luo, Jian; Kurt, Zohre; Hou, Deyi; Spain, Jim C

2015-02-03

Vapor intrusion from volatile subsurface contaminants can be mitigated by aerobic biodegradation. Laboratory column studies with contaminant sources of chlorobenzene and a mixture of chlorobenzene, 1,2-dichlorobenzene, and 1,4-dichlorobenzene showed that contaminants were rapidly degraded in thin reactive zones with high biomass and low substrate concentrations in the vicinity of the capillary fringe. Such behavior was well characterized by a model that includes oxygen-, substrate-, and biomass-dependent biodegradation kinetics along with diffusive transport processes. An analytical solution was derived to provide theoretical support for the simplification of reaction kinetics and the approximation of reactive zone location and mass flux relationships at steady state. Results demonstrate the potential of aerobic natural attenuation in the capillary fringe for preventing contaminant migration in the unsaturated zone. The solution indicates that increasing contaminant mass flux into the column creates a thinner reactive zone and pushes it toward the oxygen boundary, resulting in a shorter distance to the oxygen source and a larger oxygen mass flux that balances the contaminant mass flux. As a consequence, the aerobic biodegradation can reduce high contaminant concentrations to low levels within the capillary fringe and unsaturated zone. The results are consistent with the observations of thin reactive layers at the interface in unsaturated zones. The model considers biomass while including biodegradation in the capillary fringe and unsaturated zone and clearly demonstrates that microbial communities capable of using the contaminants as electron donors may lead to instantaneous degradation kinetics in the capillary fringe and unsaturated zone.

Automatic fringe enhancement with novel bidimensional sinusoids-assisted empirical mode decomposition.

Science.gov (United States)

Wang, Chenxing; Kemao, Qian; Da, Feipeng

2017-10-02

Fringe-based optical measurement techniques require reliable fringe analysis methods, where empirical mode decomposition (EMD) is an outstanding one due to its ability of analyzing complex signals and the merit of being data-driven. However, two challenging issues hinder the application of EMD in practical measurement. One is the tricky mode mixing problem (MMP), making the decomposed intrinsic mode functions (IMFs) have equivocal physical meaning; the other is the automatic and accurate extraction of the sinusoidal fringe from the IMFs when unpredictable and unavoidable background and noise exist in real measurements. Accordingly, in this paper, a novel bidimensional sinusoids-assisted EMD (BSEMD) is proposed to decompose a fringe pattern into mono-component bidimensional IMFs (BIMFs), with the MMP solved; properties of the resulted BIMFs are then analyzed to recognize and enhance the useful fringe component. The decomposition and the fringe recognition are integrated and the latter provides a feedback to the former, helping to automatically stop the decomposition to make the algorithm simpler and more reliable. A series of experiments show that the proposed method is accurate, efficient and robust to various fringe patterns even with poor quality, rendering it a potential tool for practical use.

44 CFR 208.40 - Reimbursement of fringe benefit costs during Activation.

Science.gov (United States)

2010-10-01

... reimbursement sought from DHS. (c) DHS will not reimburse the Sponsoring Agency for fringe benefit costs for... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Reimbursement of fringe... RESCUE RESPONSE SYSTEM Response Cooperative Agreements § 208.40 Reimbursement of fringe benefit costs...

Spectral dispersion and fringe detection in IOTA

Science.gov (United States)

Traub, W. A.; Lacasse, M. G.; Carleton, N. P.

1990-01-01

Pupil plane beam combination, spectral dispersion, detection, and fringe tracking are discussed for the IOTA interferometer. A new spectrometer design is presented in which the angular dispersion with respect to wavenumber is nearly constant. The dispersing element is a type of grism, a series combination of grating and prism, in which the constant parts of the dispersion add, but the slopes cancel. This grism is optimized for the display of channelled spectra. The dispersed fringes can be tracked by a matched-filter photon-counting correlator algorithm. This algorithm requires very few arithmetic operations per detected photon, making it well-suited for real-time fringe tracking. The algorithm is able to adapt to different stellar spectral types, intensity levels, and atmospheric time constants. The results of numerical experiments are reported.

Optical sensor technology for simultaneous measurement of particle speed and concentration of micro sized particles

DEFF Research Database (Denmark)

Clausen, Casper; Han, Anpan; Kristensen, Martin

2013-01-01

Experimental characterization of a sensor technology that can measure particle speed and concentration simultaneously in liquids and gases is presented here. The basic sensor principle is based on an optical element that shapes a light beam into well-defined fringes. The technology can be described...

29 CFR 4.177 - Discharging fringe benefit obligations by equivalent means.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Discharging fringe benefit obligations by equivalent means... CONTRACTS Compensation Standards Compliance with Compensation Standards § 4.177 Discharging fringe benefit obligations by equivalent means. (a) In general. (1) Section 2(a)(2) of the Act, which provides for fringe...

Modeling of cylindrical surrounding gate MOSFETs including the fringing field effects

International Nuclear Information System (INIS)

Gupta, Santosh K.; Baishya, Srimanta

2013-01-01

A physically based analytical model for surface potential and threshold voltage including the fringing gate capacitances in cylindrical surround gate (CSG) MOSFETs has been developed. Based on this a subthreshold drain current model has also been derived. This model first computes the charge induced in the drain/source region due to the fringing capacitances and considers an effective charge distribution in the cylindrically extended source/drain region for the development of a simple and compact model. The fringing gate capacitances taken into account are outer fringe capacitance, inner fringe capacitance, overlap capacitance, and sidewall capacitance. The model has been verified with the data extracted from 3D TCAD simulations of CSG MOSFETs and was found to be working satisfactorily. (semiconductor devices)

Analytical determination of 5th-order transfer matrices of magnetic quadrupole fringing fields

International Nuclear Information System (INIS)

Hartmann, B.; Irnich, H.; Wollnik, H.

1993-01-01

The fringing-field effects on particle trajectories in magnetic quadrupoles are described to 5th order by fringing-field integrals. It is shown that this method improves the description of fringing-field effects noticeably over the so far known use of third-order fringing-field integrals. (Author)

Analysis techniques of lattice fringe images for quantified evaluation of pyrocarbon by chemical vapor infiltration.

Science.gov (United States)

Li, Miaoling; Zhao, Hongxia; Qi, Lehua; Li, Hejun

2014-10-01

Some image analysis techniques are developed for simplifying lattice fringe images of deposited pyrocarbon in carbon/carbon composites by chemical vapor infiltration. They are mainly the object counting method for detecting the optimum threshold, the self-adaptive morphological filtering, the node-separation technique for breaking the aggregate fringes, and some post processing algorithms for reconstructing the fringes. The simplified fringes are the foundation for defining and extracting quantitative nanostructure parameters of pyrocarbon. The frequency filter window of a Fourier transform is defined as the circular band that retains only those fringes with interlayer distance between 0.3 and 0.45 nm. Some judge criteria are set to define topological relation between fringes. For example, the aspect ratio and area of fringes are employed to detect aggregate fringes. Fringe coaxality and distance between endpoints are used to judge the disconnected fringes. The optimum values are determined by using the iterative correction techniques. The best cut-off value for the short fringes is chosen only when there is a reasonable match between the mean fringe length and the value measured by X-ray diffraction. The adopted techniques have been verified to be feasible and to have the potential to convert the complex lattice fringe image to a set of distinct fringe structures.

29 CFR 4.162 - Fringe benefits under contracts exceeding $2,500.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Fringe benefits under contracts exceeding $2,500. 4.162... Compensation Standards § 4.162 Fringe benefits under contracts exceeding $2,500. (a) Pursuant to the statutory... contain a provision specifying the fringe benefits to be furnished the various classes of service...

Wavelength-independent fringe spacing in rainbows from falling neutrons

International Nuclear Information System (INIS)

Berry, M.V.

1982-01-01

For particles with speed upsilon and mass m emitted isotropically from a point source and falling under gravity g, the quantal probability density is dominated by a paraboloidal caustic decorated with paraboloidal interference fringes. Near the caustic, the fringes have a spacing independent of upsilon and hence of wavelength, given by ΔR=3.53897x(h 2 /m 2 g)sup(1/3) for the first two (brightest) fringes at the level of the source. For neutrons in the Earth's field, ΔR=0.02617mm. The effect might be difficult to detect. (author)

29 CFR 4.165 - Wage payments and fringe benefits-in general.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Wage payments and fringe benefits-in general. 4.165 Section... Compensation Standards Compliance with Compensation Standards § 4.165 Wage payments and fringe benefits—in... fringe benefits (see § 4.177). (2) The Act makes no distinction, with respect to its compensation...

29 CFR 4.50 - Types of wage and fringe benefit determinations.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Types of wage and fringe benefit determinations. 4.50... Determination Procedures § 4.50 Types of wage and fringe benefit determinations. The Administrator specifies the minimum monetary wages and fringe benefits to be paid as required under the Act in two types of...

Observation of electron beam moiré fringes in an image conversion tube

Energy Technology Data Exchange (ETDEWEB)

Lei, Yunfei; Liao, Yubo [Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Shenzhen University, Shenzhen 518060 (China); Long, Jing-hua [College of Physics Science and Technology, Shenzhen University, Shenzhen 518060 (China); Cai, Houzhi; Bai, Yanli [Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Shenzhen University, Shenzhen 518060 (China); Liu, Jinyuan, E-mail: ljy@szu.edu.cn [Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Shenzhen University, Shenzhen 518060 (China)

2016-11-15

An image conversion tube with a magnetic lens was designed to observe electron beam moiré fringes. Electron beam moiré fringes result from the interference between the photocathode and the anode meshes. The photocathode had a strip line structure with a spatial frequency of 10 L/mm. The anode mesh had a fixed spatial frequency of 10 L/mm, and could be rotated around the axis of the image tube. The changes to the fringe direction and the spacing as a function of the rotation angle between the photocathode and the anode mesh were examined. The experimental results agreed with the theoretical analysis. Moiré fringes with a modulation of ~20% were obtained using a 3 keV electron beam. - Highlights: • Observe the electron beam moiré fringes in large angle of view. • The changes to the fringe direction and the spacing as a function of the rotation angle between the two gratings were examined. • Modulations of the moiré fringes in different rotation angle are recorded.

Observation of electron beam moiré fringes in an image conversion tube

International Nuclear Information System (INIS)

Lei, Yunfei; Liao, Yubo; Long, Jing-hua; Cai, Houzhi; Bai, Yanli; Liu, Jinyuan

2016-01-01

An image conversion tube with a magnetic lens was designed to observe electron beam moiré fringes. Electron beam moiré fringes result from the interference between the photocathode and the anode meshes. The photocathode had a strip line structure with a spatial frequency of 10 L/mm. The anode mesh had a fixed spatial frequency of 10 L/mm, and could be rotated around the axis of the image tube. The changes to the fringe direction and the spacing as a function of the rotation angle between the photocathode and the anode mesh were examined. The experimental results agreed with the theoretical analysis. Moiré fringes with a modulation of ~20% were obtained using a 3 keV electron beam. - Highlights: • Observe the electron beam moiré fringes in large angle of view. • The changes to the fringe direction and the spacing as a function of the rotation angle between the two gratings were examined. • Modulations of the moiré fringes in different rotation angle are recorded.

On price taking behavior in a nonrenewable resource cartel-fringe game

NARCIS (Netherlands)

Withagen, C.A.A.M.; Benchekroun, H.

2012-01-01

We consider a nonrenewable resource game with one cartel and a set of fringe members. We show that (i) the outcomes of the closed-loop and the open-loop nonrenewable resource game with the fringe members as price takers (the cartel-fringe game à la Salant, 1976) coincide and (ii) when the number of

Fringe biasing: A variance reduction technique for optically thick meshes

Energy Technology Data Exchange (ETDEWEB)

Smedley-Stevenson, R. P. [AWE PLC, Aldermaston Reading, Berkshire, RG7 4PR (United Kingdom)

2013-07-01

Fringe biasing is a stratified sampling scheme applicable to Monte Carlo thermal radiation transport codes. The thermal emission source in optically thick cells is partitioned into separate contributions from the cell interiors (where the likelihood of the particles escaping the cells is virtually zero) and the 'fringe' regions close to the cell boundaries. Thermal emission in the cell interiors can now be modelled with fewer particles, the remaining particles being concentrated in the fringes so that they are more likely to contribute to the energy exchange between cells. Unlike other techniques for improving the efficiency in optically thick regions (such as random walk and discrete diffusion treatments), fringe biasing has the benefit of simplicity, as the associated changes are restricted to the sourcing routines with the particle tracking routines being unaffected. This paper presents an analysis of the potential for variance reduction achieved from employing the fringe biasing technique. The aim of this analysis is to guide the implementation of this technique in Monte Carlo thermal radiation codes, specifically in order to aid the choice of the fringe width and the proportion of particles allocated to the fringe (which are interrelated) in multi-dimensional simulations, and to confirm that the significant levels of variance reduction achieved in simulations can be understood by studying the behaviour for simple test cases. The variance reduction properties are studied for a single cell in a slab geometry purely absorbing medium, investigating the accuracy of the scalar flux and current tallies on one of the interfaces with the surrounding medium. (authors)

Fringe biasing: A variance reduction technique for optically thick meshes

International Nuclear Information System (INIS)

Smedley-Stevenson, R. P.

2013-01-01

Fringe biasing is a stratified sampling scheme applicable to Monte Carlo thermal radiation transport codes. The thermal emission source in optically thick cells is partitioned into separate contributions from the cell interiors (where the likelihood of the particles escaping the cells is virtually zero) and the 'fringe' regions close to the cell boundaries. Thermal emission in the cell interiors can now be modelled with fewer particles, the remaining particles being concentrated in the fringes so that they are more likely to contribute to the energy exchange between cells. Unlike other techniques for improving the efficiency in optically thick regions (such as random walk and discrete diffusion treatments), fringe biasing has the benefit of simplicity, as the associated changes are restricted to the sourcing routines with the particle tracking routines being unaffected. This paper presents an analysis of the potential for variance reduction achieved from employing the fringe biasing technique. The aim of this analysis is to guide the implementation of this technique in Monte Carlo thermal radiation codes, specifically in order to aid the choice of the fringe width and the proportion of particles allocated to the fringe (which are interrelated) in multi-dimensional simulations, and to confirm that the significant levels of variance reduction achieved in simulations can be understood by studying the behaviour for simple test cases. The variance reduction properties are studied for a single cell in a slab geometry purely absorbing medium, investigating the accuracy of the scalar flux and current tallies on one of the interfaces with the surrounding medium. (authors)

Ghost fringe removal techniques using Lissajous data presentation.

Science.gov (United States)

Erskine, David J; Eggert, J H; Celliers, P M; Hicks, D G

2016-03-01

A VISAR (Velocity Interferometer System for Any Reflector) is a Doppler velocity interferometer which is an important optical diagnostic in shockwave experiments at the national laboratories, used to measure equation of state (EOS) of materials under extreme conditions. Unwanted reflection of laser light from target windows can produce an additional component to the VISAR fringe record that can distort and obscure the true velocity signal. Accurately removing this so-called ghost artifact component is essential for achieving high accuracy EOS measurements, especially when the true light signal is only weakly reflected from the shock front. Independent of the choice of algorithm for processing the raw data into a complex fringe signal, we have found it beneficial to plot this signal as a Lissajous and seek the proper center of this path, even under time varying intensity which can shift the perceived center. The ghost contribution is then solved by a simple translation in the complex plane that recenters the Lissajous path. For continuous velocity histories, we find that plotting the fringe magnitude vs nonfringing intensity and optimizing linearity is an invaluable tool for determining accurate ghost offsets. For discontinuous velocity histories, we have developed graphically inspired methods which relate the results of two VISARs having different velocity per fringe proportionalities or assumptions of constant fringe magnitude to find the ghost offset. The technique can also remove window reflection artifacts in generic interferometers, such as in the metrology of surfaces.

Carrier and aberrations removal in interferometric fringe projection profilometry

Science.gov (United States)

Blain, P.; Michel, F.; Renotte, Y.; Habraken, S.

2012-04-01

A profilometer which takes advantage of polarization states splitting technique and monochromatic light projection method as a way to overcome ambient lighting for in-situ measurement is under development [1, 2]. Because of the Savart plate which refracts two out of axis beams, the device suffers from aberrations (mostly coma and astigmatism). These aberrations affect the quality of the sinusoidal fringe pattern. In fringe projection profilometry, the unwrapped phase distribution map contains the sum of the object's shape-related phase and carrier-fringe-related phase. In order to extract the 3D shape of the object, the carrier phase has to be removed [3, 4]. An easy way to remove both the fringe carrier and the aberrations of the optical system is to measure the phases of the test object and to measure the phase of a reference plane with the same set up and to subtract both phase maps. This time consuming technique is suitable for laboratory but not for industry. We propose a method to numerically remove both the fringe carrier and the aberrations. A first reference phase of a calibration plane is evaluated knowing the position of the different elements in the set up and the orientation of the fringes. Then a fitting of the phase map by Zernike polynomials is computed [5]. As the triangulation parameters are known during the calibration, the computation of Zernike coefficients has only to be made once. The wavefront error can be adjusted by a scale factor which depends on the position of the test object.

Improvement of a sensor unit for wrist blood pressure monitoring system

Science.gov (United States)

Koo, Sangjun; Kwon, Jongwon; Park, Yongman; Ayuzenara, Odgerel; Kim, Hiesik

2007-12-01

A blood pressure sensor unit for ubiquitous healthcare monitoring was newly developed. The digital wrist band-type blood pressure devices for home are popular already in the market. It is useful for checking blood pressure level at home and control of hypertension. Especially, it is very essential home device to check the health condition of blood circulation disease. Nowadays many product types are available. But the measurement of blood pressure is not accurate enough compared with the mechanical type. It needs to be upgraded to assure the precise health data enough to use in the hospital. The structure, feature and output signal of capacitor type pressure sensors are analyzed. An improved design of capacitor sensor is suggested. It shows more precise health data after use on a wrist band type health unit. They can be applied for remote u-health medical service.

Frequency guided methods for demodulation of a single fringe pattern.

Science.gov (United States)

Wang, Haixia; Kemao, Qian

2009-08-17

Phase demodulation from a single fringe pattern is a challenging task but of interest. A frequency-guided regularized phase tracker and a frequency-guided sequential demodulation method with Levenberg-Marquardt optimization are proposed to demodulate a single fringe pattern. Demodulation path guided by the local frequency from the highest to the lowest is applied in both methods. Since critical points have low local frequency values, they are processed last so that the spurious sign problem caused by these points is avoided. These two methods can be considered as alternatives to the effective fringe follower regularized phase tracker. Demodulation results from one computer-simulated and two experimental fringe patterns using the proposed methods will be demonstrated. (c) 2009 Optical Society of America

Demonstration of a tunable two-frequency projected fringe pattern with acousto-optic deflectors

International Nuclear Information System (INIS)

Dupont, S.; Kastelik, J. C.

2008-01-01

We report on a fringe projector for three-dimensional shape measurement. The developed instrument is able to project a two-frequency fringe pattern, each frequency is independently controlled by electronics. Moreover, each phase of the two fringe patterns is also independently adjusted. The projection system is based on the use of a pair of custom large bandwidth (40 MHz) and high efficiency (60%) TeO 2 deflectors. The developed instrument offers the combined advantages of a static two-frequency fringe projector and of a tunable single frequency fringe projector

SCALING LAW FOR THE IMPACT OF MAGNET FRINGE FIELDS

International Nuclear Information System (INIS)

WEI, J.; PAPAPHILIPPOU, Y.; TALMAN, R.

2000-01-01

A general scaling law can be derived for the relative momentum deflection produced on a particle beam by fringe fields, to leading order. The formalism is applied to two concrete examples, for magnets having dipole and quadrupole symmetry. During recent years, the impact of magnet fringe fields is becoming increasingly important for rings of relatively small circumference but large acceptance. A few years ago, following some heuristic arguments, a scaling law was proposed [1], for the relative deflection of particles passing through a magnet fringe-field. In fact, after appropriate expansion of the magnetic fields in Cartesian coordinates, which generalizes the expansions of Steffen [2], one can show that this scaling law is true for any multipole magnet, at leading order in the transverse coefficients [3]. This paper intends to provide the scaling law to estimate the impact of fringe fields in the special cases of magnets with dipole and quadrupole symmetry

Optimal defocus selection based on normed Fourier transform for digital fringe pattern profilometry.

Science.gov (United States)

Kamagara, Abel; Wang, Xiangzhao; Li, Sikun

2017-10-01

Owing to gamma-effect robustness and high-speed imaging capabilities, projector defocusing of binary-coded fringe patterns is by far the most widely used and effective technique in generating sinusoidal fringe patterns for three-dimensional optical topography measurement with digital fringe projection techniques. However, this technique is not trouble-free. It is borne with uncertainty and challenges mainly because it remains somewhat difficult to quantify and ascertain the level of defocus required for desired fidelity in sinuousness of the projected fringe pattern. Too much or too little defocusing will affect the sinuosity accuracy of fringe patterns and consequently jeopardize the quality of the measurement results. In this paper, by combining intrinsic phase spectral sensitivities and normed Fourier transform, a method to quantify the amount of defocus and subsequently select the optimal degree of sinuosity for generating digital sinusoidal fringe patterns with projector defocusing for fringe pattern optical three-dimensional profilometry is proposed. Numerical simulations plus experiments give evidence of the feasibility and validity of the proposed method in enabling an improved digital binary defocusing technique for optical phase-shift profilometry using the digital fringe projection technique.

An algorithm to remove fringe jumps and its application to microwave reflectometry

International Nuclear Information System (INIS)

Ejiri, A.; Kawahata, K.; Shinohara, K.

1997-01-01

In some plasma discharges, the phase measured by microwave reflectometry has many fringe (2π radians) jumps. A new algorithm to detect and remove fringe jumps has been developed, and applied to the data in the JIPP TII-U tokamak. Using this algorithm, quantitative properties of fringe jumps, and their effects on the analysis of phase fluctuations are investigated. It was found that the occurrence of fringe jumps obeys a Poisson process, and the time scale of jumps is distributed over a wide range. Fringe jumps affect mainly the low-frequency components of phase fluctuations. Comparison of the phase corrected by the algorithm and the phase calculated from the time smoothed signals indicates that time smoothing (or frequency filtering) is an effective way to obtain information concerning the macroscopic density profile. Fringe jump and phase runaway can be phenomenologically explained by the distribution of the complex amplitude of the reflected wave. (author)

Investigation on the properties of the formation and coherence of intense fringe near nonlinear medium slab

Science.gov (United States)

Hu, Yonghua; Qiu, Yaqiong; Li, Yang; Shi, Lin

2018-03-01

Near medium intense (NMI) fringe is a kind of intense fringe which can be formed near Kerr medium in high-power laser beam propagation. The formation properties of NMI fringe and the relations between NMI fringe and related important parameters are systematically investigated. It is found that it is the co-existence of two wirelike phase-typed scatterers in the incident beam spot which is mainly responsible for the high intensity of NMI fringe. From the viewpoint of coherent superposition, the formation process of NMI fringe is analyzed, and the mechanism that NMI fringe is formed by the coherent superposition of the localized bright fringes in the exit field of Kerr medium slab is demonstrated. The fluctuations of NMI fringe properties with beam wavelength, scatterer spacing and object distance are studied, the coherence of NMI fringe are revealed, and the approximate periodicity of the appearance of remarkable NMI fringe for these parameters are obtained. Especially, it is found that the intensity of NMI fringe is very sensitive to scatterer spacing. Besides, the laws about how NMI fringe properties will be changed by the modulation properties of scatterers and the medium thickness are demonstrated.

Single-shot color fringe projection for three-dimensional shape measurement of objects with discontinuities.

Science.gov (United States)

Dai, Meiling; Yang, Fujun; He, Xiaoyuan

2012-04-20

A simple but effective fringe projection profilometry is proposed to measure 3D shape by using one snapshot color sinusoidal fringe pattern. One color fringe pattern encoded with a sinusoidal fringe (as red component) and one uniform intensity pattern (as blue component) is projected by a digital video projector, and the deformed fringe pattern is recorded by a color CCD camera. The captured color fringe pattern is separated into its RGB components and division operation is applied to red and blue channels to reduce the variable reflection intensity. Shape information of the tested object is decoded by applying an arcsine algorithm on the normalized fringe pattern with subpixel resolution. In the case of fringe discontinuities caused by height steps, or spatially isolated surfaces, the separated blue component is binarized and used for correcting the phase demodulation. A simple and robust method is also introduced to compensate for nonlinear intensity response of the digital video projector. The experimental results demonstrate the validity of the proposed method.

Closed fringe demodulation using phase decomposition by Fourier basis functions.

Science.gov (United States)

Kulkarni, Rishikesh; Rastogi, Pramod

2016-06-01

We report a new technique for the demodulation of a closed fringe pattern by representing the phase as a weighted linear combination of a certain number of linearly independent Fourier basis functions in a given row/column at a time. A state space model is developed with the weights of the basis functions as the elements of the state vector. The iterative extended Kalman filter is effectively utilized for the robust estimation of the weights. A coarse estimate of the fringe density based on the fringe frequency map is used to determine the initial row/column to start with and subsequently the optimal number of basis functions. The performance of the proposed method is evaluated with several noisy fringe patterns. Experimental results are also reported to support the practical applicability of the proposed method.

The Gender Pay Gap, Fringe Benefits, and Occupational Crowding.

Science.gov (United States)

Solberg, Eric; Laughlin, Teresa

1995-01-01

In estimating earnings equations for seven occupations, when fringe benefits are excluded, women receive significantly lower wages in all but the most female-dominated occupation. Including fringe benefits makes gender significant in only one occupational category. Crowding of one gender into an occupation appears the primary determinant of the…

Pendellosung fringes of silicon at low temperatures

International Nuclear Information System (INIS)

Soejima, Y.; Eto, T.; Naruoka, H.; Lu, Z.; Okazaki, A.

1997-01-01

The crystal structure o silicon has been examined by means of X-ray diffraction according to the Pendellosung method. Measurements of the fringe pattern were made for the 111, 220, 113, 004, 331, 224 and 333 diffractions in a temperature range 17-300 K. It is found that the value of the Debye temperature determined from the temperature dependence of the period of Pendellosung fringes is in good agreement with that in the literature except for the first three diffractions; for these with shorter scattering vectors, the value depends on specimen and, in some cases, is smaller than that in the literature and depends on the length of the scattering vector. It is also found that the fringe pattern is stress sensitive, and that the stress can be released at lowest temperatures. This phenomenon of a kind of aging is discussed in connection with a similar effect observed in the high-resolution measurement of the lattice spacing

In-situ position and vibration measurement of rough surfaces using laser Doppler distance sensors

Science.gov (United States)

Czarske, J.; Pfister, T.; Günther, P.; Büttner, L.

2009-06-01

In-situ measurement of distances and shapes as well as dynamic deformations and vibrations of fast moving and especially rotating objects, such as gear shafts and turbine blades, is an important task at process control. We recently developed a laser Doppler distance frequency sensor, employing two superposed fan-shaped interference fringe systems with contrary fringe spacing gradients. Via two Doppler frequency evaluations the non-incremental position (i.e. distance) and the tangential velocity of rotating bodies are determined simultaneously. The distance uncertainty is in contrast to e.g. triangulation in principle independent of the object velocity. This unique feature allows micrometer resolutions of fast moved rough surfaces. The novel sensor was applied at turbo machines in order to control the tip clearance. The measurements at a transonic centrifugal compressor were performed during operation at up to 50,000 rpm, i.e. 586 m/s velocity of the blade tips. Due to the operational conditions such as temperatures of up to 300 °C, a flexible and robust measurement system with a passive fiber-coupled sensor, using diffractive optics, has been realized. Since the tip clearance of individual blades could be temporally resolved an analysis of blade vibrations was possible. A Fourier transformation of the blade distances results in an average period of 3 revolutions corresponding to a frequency of 1/3 of the rotary frequency. Additionally, a laser Doppler distance sensor using two tilted fringe systems and phase evaluation will be presented. This phase sensor exhibits a minimum position resolution of σz = 140 nm. It allows precise in-situ shape measurements at grinding and turning processes.

Dispersed Fringe Sensing Analysis - DFSA

Science.gov (United States)

Sigrist, Norbert; Shi, Fang; Redding, David C.; Basinger, Scott A.; Ohara, Catherine M.; Seo, Byoung-Joon; Bikkannavar, Siddarayappa A.; Spechler, Joshua A.

2012-01-01

Dispersed Fringe Sensing (DFS) is a technique for measuring and phasing segmented telescope mirrors using a dispersed broadband light image. DFS is capable of breaking the monochromatic light ambiguity, measuring absolute piston errors between segments of large segmented primary mirrors to tens of nanometers accuracy over a range of 100 micrometers or more. The DFSA software tool analyzes DFS images to extract DFS encoded segment piston errors, which can be used to measure piston distances between primary mirror segments of ground and space telescopes. This information is necessary to control mirror segments to establish a smooth, continuous primary figure needed to achieve high optical quality. The DFSA tool is versatile, allowing precise piston measurements from a variety of different optical configurations. DFSA technology may be used for measuring wavefront pistons from sub-apertures defined by adjacent segments (such as Keck Telescope), or from separated sub-apertures used for testing large optical systems (such as sub-aperture wavefront testing for large primary mirrors using auto-collimating flats). An experimental demonstration of the coarse-phasing technology with verification of DFSA was performed at the Keck Telescope. DFSA includes image processing, wavelength and source spectral calibration, fringe extraction line determination, dispersed fringe analysis, and wavefront piston sign determination. The code is robust against internal optical system aberrations and against spectral variations of the source. In addition to the DFSA tool, the software package contains a simple but sophisticated MATLAB model to generate dispersed fringe images of optical system configurations in order to quickly estimate the coarse phasing performance given the optical and operational design requirements. Combining MATLAB (a high-level language and interactive environment developed by MathWorks), MACOS (JPL s software package for Modeling and Analysis for Controlled Optical

Investigation on the properties of the formation and coherence of intense fringe near nonlinear medium slab

Directory of Open Access Journals (Sweden)

Yonghua Hu

2018-03-01

Full Text Available Near medium intense (NMI fringe is a kind of intense fringe which can be formed near Kerr medium in high-power laser beam propagation. The formation properties of NMI fringe and the relations between NMI fringe and related important parameters are systematically investigated. It is found that it is the co-existence of two wirelike phase-typed scatterers in the incident beam spot which is mainly responsible for the high intensity of NMI fringe. From the viewpoint of coherent superposition, the formation process of NMI fringe is analyzed, and the mechanism that NMI fringe is formed by the coherent superposition of the localized bright fringes in the exit field of Kerr medium slab is demonstrated. The fluctuations of NMI fringe properties with beam wavelength, scatterer spacing and object distance are studied, the coherence of NMI fringe are revealed, and the approximate periodicity of the appearance of remarkable NMI fringe for these parameters are obtained. Especially, it is found that the intensity of NMI fringe is very sensitive to scatterer spacing. Besides, the laws about how NMI fringe properties will be changed by the modulation properties of scatterers and the medium thickness are demonstrated. Keywords: High-power laser beam, Nonlinear propagation, Kerr medium, Small-scale scatterer, Nonlinear imaging

Theoretical analysis of moiré fringe multiplication under a scanning electron microscope

International Nuclear Information System (INIS)

Li, Yanjie; Xie, Huimin; Chen, Pengwan; Zhang, Qingming

2011-01-01

In this study, theoretical analysis and experimental verification of fringe multiplication under a scanning electron microscope (SEM) are presented. Fringe multiplication can be realized by enhancing the magnification or the number of scanning lines under the SEM. A universal expression of the pitch of moiré fringes is deduced. To apply this method to deformation measurement, the calculation formulas of strain and displacement are derived. Compared to natural moiré, the displacement sensitivity is increased by fringe multiplication while the strain sensitivity may be retained or enhanced depending on the number of scanning lines used. The moiré patterns are formed by the interference of a 2000 lines mm −1 grating with the scanning lines of SEM, and the measured parameters of moiré fringes from experimental results agree well with theoretical analysis

Adaptive fringe-pattern projection for image saturation avoidance in 3D surface-shape measurement.

Science.gov (United States)

Li, Dong; Kofman, Jonathan

2014-04-21

In fringe-projection 3D surface-shape measurement, image saturation results in incorrect intensities in captured images of fringe patterns, leading to phase and measurement errors. An adaptive fringe-pattern projection (AFPP) method was developed to adapt the maximum input gray level in projected fringe patterns to the local reflectivity of an object surface being measured. The AFPP method demonstrated improved 3D measurement accuracy by avoiding image saturation in highly-reflective surface regions while maintaining high intensity modulation across the entire surface. The AFPP method can avoid image saturation and handle varying surface reflectivity, using only two prior rounds of fringe-pattern projection and image capture to generate the adapted fringe patterns.

26 CFR 1.162-25 - Deductions with respect to noncash fringe benefits.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Deductions with respect to noncash fringe... Corporations § 1.162-25 Deductions with respect to noncash fringe benefits. (a) [Reserved] (b) Employee. If an employer provides the use of a vehicle (as defined in § 1.61-21(e)(2)) to an employee as a noncash fringe...

Portable air quality sensor unit for participatory monitoring: an end-to-end VESNA-AQ based prototype

Science.gov (United States)

Vucnik, Matevz; Robinson, Johanna; Smolnikar, Miha; Kocman, David; Horvat, Milena; Mohorcic, Mihael

2015-04-01

Key words: portable air quality sensor, CITI-SENSE, participatory monitoring, VESNA-AQ The emergence of low-cost easy to use portable air quality sensors units is opening new possibilities for individuals to assess their exposure to air pollutants at specific place and time, and share this information through the Internet connection. Such portable sensors units are being used in an ongoing citizen science project called CITI-SENSE, which enables citizens to measure and share the data. The project aims through creating citizens observatories' to empower citizens to contribute to and participate in environmental governance, enabling them to support and influence community and societal priorities as well as associated decision making. An air quality measurement system based on VESNA sensor platform was primarily designed within the project for the use as portable sensor unit in selected pilot cities (Belgrade, Ljubljana and Vienna) for monitoring outdoor exposure to pollutants. However, functionally the same unit with different set of sensors could be used for example as an indoor platform. The version designed for the pilot studies was equipped with the following sensors: NO2, O3, CO, temperature, relative humidity, pressure and accelerometer. The personal sensor unit is battery powered and housed in a plastic box. The VESNA-based air quality (AQ) monitoring system comprises the VESNA-AQ portable sensor unit, a smartphone app and the remote server. Personal sensor unit supports wireless connection to an Android smartphone via built-in Wi-Fi. The smartphone in turn serves also as the communication gateway towards the remote server using any of available data connections. Besides the gateway functionality the role of smartphone is to enrich data coming from the personal sensor unit with the GPS location, timestamps and user defined context. This, together with an accelerometer, enables the user to better estimate ones exposure in relation to physical activities, time

Analysis of Fringe Field Formed Inside LDA Measurement Volume Using Compact Two Hololens Imaging Systems

Science.gov (United States)

Ghosh, Abhijit; Nirala, A. K.; Yadav, H. L.

2018-03-01

We have designed and fabricated four LDA optical setups consisting of aberration compensated four different compact two hololens imaging systems. We have experimentally investigated and realized a hololens recording geometry which is interferogram of converging spherical wavefront with mutually coherent planar wavefront. Proposed real time monitoring and actual fringe field analysis techniques allow complete characterizations of fringes formed at measurement volume and permit to evaluate beam quality, alignment and fringe uniformity with greater precision. After experimentally analyzing the fringes formed at measurement volume by all four imaging systems, it is found that fringes obtained using compact two hololens imaging systems get improved both qualitatively and quantitatively compared to that obtained using conventional imaging system. Results indicate qualitative improvement of non-uniformity in fringe thickness and micro intensity variations perpendicular to the fringes, and quantitative improvement of 39.25% in overall average normalized standard deviations of fringe width formed by compact two hololens imaging systems compare to that of conventional imaging system.

Marker encoded fringe projection profilometry for efficient 3D model acquisition.

Science.gov (United States)

Budianto, B; Lun, P K D; Hsung, Tai-Chiu

2014-11-01

This paper presents a novel marker encoded fringe projection profilometry (FPP) scheme for efficient 3-dimensional (3D) model acquisition. Traditional FPP schemes can introduce large errors to the reconstructed 3D model when the target object has an abruptly changing height profile. For the proposed scheme, markers are encoded in the projected fringe pattern to resolve the ambiguities in the fringe images due to that problem. Using the analytic complex wavelet transform, the marker cue information can be extracted from the fringe image, and is used to restore the order of the fringes. A series of simulations and experiments have been carried out to verify the proposed scheme. They show that the proposed method can greatly improve the accuracy over the traditional FPP schemes when reconstructing the 3D model of objects with abruptly changing height profile. Since the scheme works directly in our recently proposed complex wavelet FPP framework, it enjoys the same properties that it can be used in real time applications for color objects.

General filtering method for electronic speckle pattern interferometry fringe images with various densities based on variational image decomposition.

Science.gov (United States)

Li, Biyuan; Tang, Chen; Gao, Guannan; Chen, Mingming; Tang, Shuwei; Lei, Zhenkun

2017-06-01

Filtering off speckle noise from a fringe image is one of the key tasks in electronic speckle pattern interferometry (ESPI). In general, ESPI fringe images can be divided into three categories: low-density fringe images, high-density fringe images, and variable-density fringe images. In this paper, we first present a general filtering method based on variational image decomposition that can filter speckle noise for ESPI fringe images with various densities. In our method, a variable-density ESPI fringe image is decomposed into low-density fringes, high-density fringes, and noise. A low-density fringe image is decomposed into low-density fringes and noise. A high-density fringe image is decomposed into high-density fringes and noise. We give some suitable function spaces to describe low-density fringes, high-density fringes, and noise, respectively. Then we construct several models and numerical algorithms for ESPI fringe images with various densities. And we investigate the performance of these models via our extensive experiments. Finally, we compare our proposed models with the windowed Fourier transform method and coherence enhancing diffusion partial differential equation filter. These two methods may be the most effective filtering methods at present. Furthermore, we use the proposed method to filter a collection of the experimentally obtained ESPI fringe images with poor quality. The experimental results demonstrate the performance of our proposed method.

REMOVAL OF SPECTRO-POLARIMETRIC FRINGES BY TWO-DIMENSIONAL PATTERN RECOGNITION

International Nuclear Information System (INIS)

Casini, R.; Judge, P. G.; Schad, T. A.

2012-01-01

We present a pattern-recognition-based approach to the problem of the removal of polarized fringes from spectro-polarimetric data. We demonstrate that two-dimensional principal component analysis can be trained on a given spectro-polarimetric map in order to identify and isolate fringe structures from the spectra. This allows us, in principle, to reconstruct the data without the fringe component, providing an effective and clean solution to the problem. The results presented in this paper point in the direction of revising the way that science and calibration data should be planned for a typical spectro-polarimetric observing run.

SensInDenT-Noncontact Sensors Integrated Into Dental Treatment Units.

Science.gov (United States)

Teichmann, Daniel; Teichmann, Maren; Weitz, Philippe; Wolfart, Stefan; Leonhardt, Steffen; Walter, Marian

2017-02-01

This paper presents the first system design (SensInDenT) for noncontact cardiorespiratory monitoring during dental treatment. The system is integrated into a dental treatment unit, and combines sensors based on electromagnetic, optical, and mechanical coupling at different sensor locations. The measurement principles and circuits are described and a system overview is presented. Furthermore, a first proof of concept is provided by taking measurements in healthy volunteers under laboratory conditions.

49 CFR 1242.50 - Fringe benefits (account 12-27-00).

Science.gov (United States)

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Fringe benefits (account 12-27-00). 1242.50 Section 1242.50 Transportation Other Regulations Relating to Transportation (Continued) SURFACE...-Equipment § 1242.50 Fringe benefits (account 12-27-00). Separate common expenses in proportion to the...

49 CFR 1242.63 - Fringe benefits (account 12-51-00).

Science.gov (United States)

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Fringe benefits (account 12-51-00). 1242.63 Section 1242.63 Transportation Other Regulations Relating to Transportation (Continued) SURFACE...-Transportation § 1242.63 Fringe benefits (account 12-51-00). Separate common expenses in proportion to the...

49 CFR 1242.85 - Fringe benefits (account 12-63-00).

Science.gov (United States)

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Fringe benefits (account 12-63-00). 1242.85 Section 1242.85 Transportation Other Regulations Relating to Transportation (Continued) SURFACE....85 Fringe benefits (account 12-63-00). Separate the common expenses in proportion to the total common...

49 CFR 1242.75 - Fringe benefits (account 12-53-00).

Science.gov (United States)

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Fringe benefits (account 12-53-00). 1242.75 Section 1242.75 Transportation Other Regulations Relating to Transportation (Continued) SURFACE...-Transportation § 1242.75 Fringe benefits (account 12-53-00). Separate common expenses in proportion to the...

49 CFR 1242.80 - Fringe benefits (account 12-55-00).

Science.gov (United States)

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Fringe benefits (account 12-55-00). 1242.80 Section 1242.80 Transportation Other Regulations Relating to Transportation (Continued) SURFACE...-Transportation § 1242.80 Fringe benefits (account 12-55-00). Separate common expenses in proportion to the...

49 CFR 1242.70 - Fringe benefits (account 12-52-00).

Science.gov (United States)

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Fringe benefits (account 12-52-00). 1242.70 Section 1242.70 Transportation Other Regulations Relating to Transportation (Continued) SURFACE...-Transportation § 1242.70 Fringe benefits (account 12-52-00). Separate common expenses in proportion to the...

49 CFR 1242.38 - Fringe benefits (account 12-26-00).

Science.gov (United States)

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Fringe benefits (account 12-26-00). 1242.38 Section 1242.38 Transportation Other Regulations Relating to Transportation (Continued) SURFACE...-Equipment § 1242.38 Fringe benefits (account 12-26-00). Separate common expenses in proportion to the split...

The quest for synergy when developing the urban fringe

DEFF Research Database (Denmark)

Hansen, Jesper Rohr; Engberg, Lars A.

How can planning policies related to urban fringe development and disadvantaged neighbourhoods create synergy? This question is approached and answered by various research fields and explored on various urban-planning levels, displaying case-studies related to urban regeneration, post......-industrial and suburban development and urban fringe literature. The present paper adds to these discussions by analysing two case-studies in Denmark in which local government pursue traditional urban-growth strategies in urban-fringe development - a post-industrial harbour and a large suburb, located just outside...... analyses this synergy by first describing the legislative, interventionist and financial context for urban-growth strategies deployed in the cases. On this background, the paper explores synergy potential related to policy as well as private-sector actors (local businesses, social housing organizations...

Two-shot fringe pattern phase-amplitude demodulation using Gram-Schmidt orthonormalization with Hilbert-Huang pre-filtering.

Science.gov (United States)

Trusiak, Maciej; Patorski, Krzysztof

2015-02-23

Gram-Schmidt orthonormalization is a very fast and efficient method for the fringe pattern phase demodulation. It requires only two arbitrarily phase-shifted frames. Images are treated as vectors and upon orthogonal projection of one fringe vector onto another the quadrature fringe pattern pair is obtained. Orthonormalization process is very susceptible, however, to noise, uneven background and amplitude modulation fluctuations. The Hilbert-Huang transform based preprocessing is proposed to enhance fringe pattern phase demodulation by filtering out the spurious noise and background illumination and performing fringe normalization. The Gram-Schmidt orthonormalization process error analysis is provided and its filtering-expanded capabilities are corroborated analyzing DSPI fringes and performing amplitude demodulation of Bessel fringes. Synthetic and experimental fringe pattern analyses presented to validate the proposed technique show that it compares favorably with other pre-filtering schemes, i.e., Gaussian filtering and continuous wavelet transform.

Dynamic consistency of leader/fringe models of exhaustible resource markets

International Nuclear Information System (INIS)

Pelot, R.P.

1990-01-01

A dynamic feedback pricing model is developed for a leader/fringe supply market of exhaustible resources. The discrete game optimization model includes marginal costs which may be quadratic functions of cumulative production, a linear demand curve and variable length periods. The multiperiod formulation is based on the nesting of later periods' Kuhn-Tucker conditions into earlier periods' optimizations. This procedure leads to dynamically consistent solutions where the leader's strategy is credible as he has no incentive to alter his original plan at some later stage. A static leader-fringe model may yield multiple local optima. This can result in the leader forcing the fringe to produce at their capacity constraint, which would otherwise be non-binding if it is greater than the fringe's unconstrained optimal production rate. Conditions are developed where the optimal solution occurs at a corner where constraints meet, of which limit pricing is a special case. The 2-period leader/fringe feedback model is compared to the computationally simpler open-loop model. Under certain conditions, the open-loop model yields the same result as the feedback model. A multiperiod feedback model of the world oil market with OPEC as price-leader and the remaining world oil suppliers comprising the fringe is compared with the open-loop solution. The optimal profits and prices are very similar, but large differences in production rates may occur. The exhaustion date predicted by the open-loop model may also differ from the feedback outcome. Some numerical tests result in non-contiguous production periods for a player or limit pricing phases. 85 refs., 60 figs., 30 tabs

Effective bias removal for fringe projection profilometry using the dual-tree complex wavelet transform.

Science.gov (United States)

Ng, William Wai-Lam; Lun, Daniel Pak-Kong

2012-08-20

When reconstructing the three-dimensional (3D) object height profile using the fringe projection profilometry (FPP) technique, the light intensity reflected from the object surface can yield abruptly changing bias in the captured fringe image, which leads to severe reconstruction error. The traditional approach tries to remove the bias by suppressing the zero spectrum of the fringe image. It is based on the assumption that the aliasing between the frequency spectrum of the bias, which is around the zero frequency, and the frequency spectrum of the fringe is negligible. This, however, is not the case in practice. In this paper, we propose a novel (to our knowledge) technique to eliminate the bias in the fringe image using the dual-tree complex wavelet transform (DT-CWT). The new approach successfully identifies the features of bias, fringe, and noise in the DT-CWT domain, which allows the bias to be effectively extracted from a noisy fringe image. Experimental results show that the proposed algorithm is superior to the traditional methods and facilitates accurate reconstruction of objects' 3D models.

Manic fringe inhibits tumor growth by suppressing Notch3 degradation in lung cancer.

Science.gov (United States)

Yi, Fuming; Amarasinghe, Baru; Dang, Thao P

2013-01-01

Notch signaling plays an essential role in development as well as cancer. We have previously shown that Notch3 is important for lung cancer growth and survival. Notch receptors are activated through the interaction with their ligands, resulting in proteolytic cleavage of the receptors. This interaction is modulated by Fringe, a family of fucose-specific β1,3 N-acetylglucosaminyltransferases that modify the extracellular subunit of Notch receptors. Studies in developmental models showed that Fringe enhances Notch's response to Delta ligands at the expense of Jagged ligands. We observed that Manic Fringe expression is down-regulated in lung cancer. Since Jagged1, a known ligand for Notch3, is often over-expressed in lung cancer, we hypothesized that Fringe negatively regulates Notch3 activation. In this study, we show that re-expression of Manic Fringe down-regulates Notch3 target genes HES1 and HeyL and reduces tumor phenotype in vitro and in vivo. The mechanism for this phenomenon appears to be related to modulation of Notch3 protein stability. Proteasome inhibition reverses Manic Fringe-induced protein turnover. Taken together, our data provide the first evidence that Manic Fringe functions as a tumor suppressor in the lung and that the mechanism of its anti-tumor activity is mediated by inhibition of Notch3 activation.

Note: Using a Kösters prism to create a fringe pattern.

Science.gov (United States)

Capellmann, R F; Bewerunge, J; Platten, F; Egelhaaf, S U

2017-05-01

The interference of two crossed laser beams results in a standing wave. Such fringe patterns are exploited in different instruments such as interferometers or laser-Doppler anemometers. We create a fringe pattern in the sample plane of a microscope using a compact apparatus based on a Kösters prism. The fringe pattern is shown to be spatially and temporally very stable, covers a large area, and its spacing is easily tunable. In addition, we exploit it to impose a sinusoidal potential on colloidal particles.

Acoustic grating fringe projector for high-speed and high-precision three-dimensional shape measurements

International Nuclear Information System (INIS)

Yin Xuebing; Zhao Huijie; Zeng Junyu; Qu Yufu

2007-01-01

A new acoustic grating fringe projector (AGFP) was developed for high-speed and high-precision 3D measurement. A new acoustic grating fringe projection theory is also proposed to describe the optical system. The AGFP instrument can adjust the spatial phase and period of fringes with unprecedented speed and accuracy. Using rf power proportional-integral-derivative (PID) control and CCD synchronous control, we obtain fringes with fine sinusoidal characteristics and realize high-speed acquisition of image data. Using the device, we obtained a precise phase map for a 3D profile. In addition, the AGFP can work in running fringe mode, which could be applied in other measurement fields

Three-dimensional displacement measurement by fringe projection and speckle photography

International Nuclear Information System (INIS)

Barrientos, B.; Garcia-Marquez, J.; Cerca, M.; Hernandez-Bernal, C.

2008-01-01

3D displacement fields are measured by the combination of two optical methods, fringe projection and speckle photography. The use of only one camera recording the necessary information implies that no calibration procedures are necessary as is the case in techniques based on stereoscopy. The out-of-plane displacement is measured by fringe projection whereas speckle photography yields the 2-D in-plane component. To show the feasibility of the technique, we analyze a detailed morphological spatio-temporal evolution of a model of the Earth's crust while subjected to compression forces. The results show that the combination of fringe projection and speckle photography is well suited for this type of studies

A Fiber-Optic Sensor for Leak Detection in a Space Environment

Science.gov (United States)

Sinko, John E.; Korman, Valentin; Hendrickson, Adam; Polzin, Kurt A.

2009-01-01

A miniature fiber-optic, laser-based, interferometric leak detector is presented for application as a means to detect on-orbit gas leaks. The sensor employs a fiber-coupled modified Michelson interferometer to detect gas leaks by measuring an increase in gas density in the sensing region. Monitoring changes in the fringe pattern output by the interferometer allows for direct measurement of the gas density in the sensing region and, under the assumption of an equation of state, this can be used to obtain a pressure measurement. Measurements obtained over a pressure range from 20 mtorr to 760 torr using a prototypical interferometer on working gases of air, nitrogen, argon, and helium generally exhibit agreement with a theoretical prediction of the pressure increase required before an interference fringe completely moves over the detector. Additional measurements performed on various gases demonstrate the range of detectable species, measuring sub-torr pressure changes in the process. A high-fidelity measurement places the ultimate pressure resolution for this particular sensor configuration in the 10 mtorr range. Time-resolved data prove the capability of this sensor to detect fast gas flow phenomena associated with transients and pressure waves.

Development of an Emergency Locking Unit for a Belt-In-Seat (BIS System Using a MEMS Acceleration Sensor

Directory of Open Access Journals (Sweden)

Chang Hyun Baek

2010-04-01

Full Text Available This paper proposes an emergency locking unit (ELU for a seat belt retractor which is mounted on the back frame of a vehicle seat. The proposed unit uses a recliner sensor based on a MEMS acceleration sensor and solenoid mechanism. The seat has an upper frame supported to tilt on a lower frame. The retractor in belt in seat (BIS system is supported by the upper frame. The proposed recliner sensor based on a MEMS acceleration sensor comprises orientation means for maintaining a predetermined orientation of emergency relative to the lower frame independently of the force of gravity when the upper frame tilts on the lower frame. Experimental results show that the developed recliner sensor unit operates effectively with respect to rollover angles. Thus, the developed unit will have a considerable potential to offer a new design concept in BIS system.

Image decomposition model Shearlet-Hilbert-L2 with better performance for denoising in ESPI fringe patterns.

Science.gov (United States)

Xu, Wenjun; Tang, Chen; Su, Yonggang; Li, Biyuan; Lei, Zhenkun

2018-02-01

In this paper, we propose an image decomposition model Shearlet-Hilbert-L 2 with better performance for denoising in electronic speckle pattern interferometry (ESPI) fringe patterns. In our model, the low-density fringes, high-density fringes, and noise are, respectively, described by shearlet smoothness spaces, adaptive Hilbert space, and L 2 space and processed individually. Because the shearlet transform has superior directional sensitivity, our proposed Shearlet-Hilbert-L 2 model achieves commendable filtering results for various types of ESPI fringe patterns, including uniform density fringe patterns, moderately variable density fringe patterns, and greatly variable density fringe patterns. We evaluate the performance of our proposed Shearlet-Hilbert-L 2 model via application to two computer-simulated and nine experimentally obtained ESPI fringe patterns with various densities and poor quality. Furthermore, we compare our proposed model with windowed Fourier filtering and coherence-enhancing diffusion, both of which are the state-of-the-art methods for ESPI fringe patterns denoising in transform domain and spatial domain, respectively. We also compare our proposed model with the previous image decomposition model BL-Hilbert-L 2 .

On laser sensor image fringe detection and mitigation in real-time processing based on firmware supported Hilbert-Huang Transform for 2-Dimensions

Data.gov (United States)

National Aeronautics and Space Administration — In physics, interference is a phenomenon in which two waves superimpose to form a new complex wave and fringes are observed wherever the two or more waves overlap....

Decorrelation and fringe visibility: On the limiting behavior of varous electronic speckle pattern correlation interferometers

DEFF Research Database (Denmark)

Owner-Petersen, Mette

1996-01-01

I discuss the behavior of fringe formation in image-plane electronic speckle-pattern correlation interferometers as the limit of total decorrelation is approached. The interferometers are supposed to operate in the difference mode. The effect of decorrelation will be a decrease in fringe visibility...... until the limit of total decorrelation, when no fringes will be formed, is reached. A quantitative evaluation of the partially decorrelated fringe pattern is presented for the case of decorrelation due to both tilt and in-plane translation of an object surface element. It is shown that the fringe...

Fringe fields modeling for the high luminosity LHC large aperture quadrupoles

CERN Document Server

Dalena, B; Payet, J; Chancé, A; Brett, D R; Appleby, R B; De Maria, R; Giovannozzi, M

2014-01-01

The HL-LHC Upgrade project relies on large aperture magnets (mainly the inner Triplet and the separation dipole D1). The beam is much more sensitive to non-linear perturbations in this region, such as those induced by the fringe fields of the low-beta quadrupoles. Different tracking models are compared in order to provide a numerical estimate of the impact of fringe fields for the actual design of the inner triplet quadrupoles. The implementation of the fringe fields in SixTrack, to be used for dynamic apertures studies, is also discussed.

Three-dimensional trace measurements for fast-moving objects using binary-encoded fringe projection techniques.

Science.gov (United States)

Su, Wei-Hung; Kuo, Cho-Yo; Kao, Fu-Jen

2014-08-20

A fringe projection technique to trace the shape of a fast-moving object is proposed. A binary-encoded fringe pattern is illuminated by a strobe lamp and then projected onto the moving object at a sequence of time. Phases of the projected fringes obtained from the sequent measurements are extracted by the Fourier transform method. Unwrapping is then performed with reference to the binary-encoded fringe pattern. Even though the inspected object is colorful, fringe orders can be identified. A stream of profiles is therefore retrieved from the sequent unwrapped phases. This makes it possible to analyze physical properties of the dynamic objects. Advantages of the binary-encoded fringe pattern for phase unwrapping also include (1) reliable performance for colorful objects, spatially isolated objects, and surfaces with large depth discontinuities; (2) unwrapped errors only confined in a local area; and (3) low computation cost.

Single shot fringe pattern phase demodulation using Hilbert-Huang transform aided by the principal component analysis.

Science.gov (United States)

Trusiak, Maciej; Służewski, Łukasz; Patorski, Krzysztof

2016-02-22

Hybrid single shot algorithm for accurate phase demodulation of complex fringe patterns is proposed. It employs empirical mode decomposition based adaptive fringe pattern enhancement (i.e., denoising, background removal and amplitude normalization) and subsequent boosted phase demodulation using 2D Hilbert spiral transform aided by the Principal Component Analysis method for novel, correct and accurate local fringe direction map calculation. Robustness to fringe pattern significant noise, uneven background and amplitude modulation as well as local fringe period and shape variations is corroborated by numerical simulations and experiments. Proposed automatic, adaptive, fast and comprehensive fringe analysis solution compares favorably with other previously reported techniques.

Proton moire fringes for diagnosing electromagnetic fields in opaque materials and plasmas

International Nuclear Information System (INIS)

Mackinnon, A.J.; Patel, P.K.; Price, D.W.; Hicks, D.; Romagnani, L.; Borghesi, M.

2003-01-01

High contrast proton moire fringes have been obtained in a laser-produced proton beam. Moire fringes with modulation of 20%-30% were observed in protons with energies in the range of 4-7 MeV. Monte Carlo simulations with simple test fields showed that shifts in the moire fringes can be used to give quantitative information on the strength of transient electromagnetic fields inside plasmas and materials that are opaque to conventional probing methods

Analysis of the localization of Michelson interferometer fringes using Fourier optics and temporal coherence

International Nuclear Information System (INIS)

Narayanamurthy, C S

2009-01-01

Fringes formed in a Michelson interferometer never localize in any plane, in the detector plane and in the localization plane. Instead, the fringes are assumed to localize at infinity. Except for some explanation in Principles of Optics by Born and Wolf (1964 (New York: Macmillan)), the fringe localization phenomena of Michelson's interferometer have never been analysed seriously in any book. Because Michelson's interferometer is one of the important and fundamental optical experiments taught at both undergraduate and graduate levels, it would be appropriate to explain the localization of these fringes. In this paper, we analyse the localization of Michelson interferometer fringes using Fourier optics and temporal coherence, and show that they never localize at any plane even at infinity

The first F-ring modified ciguatoxin analogue showing significant toxicity.

Science.gov (United States)

Ishihara, Yuuki; Lee, Nayoung; Oshiro, Naomasa; Matsuoka, Shigeru; Yamashita, Shuji; Inoue, Masayuki; Hirama, Masahiro

2010-05-07

Ciguatoxins, the principal causative toxins of ciguatera seafood poisoning, are potent neurotoxic polycyclic ethers. We report herein the total synthesis of a 10-membered F-ring analogue of 51-hydroxyCTX3C, which constitutes the first example of an F-ring modified ciguatoxin that exhibits potent cytotoxicity as well as mouse acute toxicity.

Temporal fringe pattern analysis with parallel computing

International Nuclear Information System (INIS)

Tuck Wah Ng; Kar Tien Ang; Argentini, Gianluca

2005-01-01

Temporal fringe pattern analysis is invaluable in transient phenomena studies but necessitates long processing times. Here we describe a parallel computing strategy based on the single-program multiple-data model and hyperthreading processor technology to reduce the execution time. In a two-node cluster workstation configuration we found that execution periods were reduced by 1.6 times when four virtual processors were used. To allow even lower execution times with an increasing number of processors, the time allocated for data transfer, data read, and waiting should be minimized. Parallel computing is found here to present a feasible approach to reduce execution times in temporal fringe pattern analysis

Deposition gradients across mangrove fringes

NARCIS (Netherlands)

Horstman, Erik Martijn; Mullarney, Julia C.; Bryan, K.R.; Sandwell, Dean R.; Aagaard, Troels; Deigaard, Rolf; Fuhrman, David

2017-01-01

Observations in a mangrove in the Whangapoua Harbour, New Zealand, have shown that deposition rates are greatest in the fringing zone between the tidal flats and the mangrove forest, where the vegetation is dominated by a cover of pneumatophores (i.e. pencil roots). Current speeds and suspended

20 CFR 641.565 - What policies govern the provision of wages and fringe benefits to participants?

Science.gov (United States)

2010-04-01

... and fringe benefits to participants? 641.565 Section 641.565 Employees' Benefits EMPLOYMENT AND... PROGRAM Services to Participants § 641.565 What policies govern the provision of wages and fringe benefits...) Fringe benefits—(1) Required fringe benefits. Except as provided in paragraphs (b)(3) and (b)(4) of this...

Feedback-stabilized fractional fringe laser interferometer for plasma density measurements

International Nuclear Information System (INIS)

Schneider, J.; Robertson, S.

1979-01-01

A feedback stabilization technique is described for a fractional fringe interferometer measuring plasma electron densities. Using this technique, a CO 2 laser Michelson interferometer with a pyroelectric detector exhibited a sensitivity of 3.4 x 10 -4 fringe on a 1-ms time scale and, due to acoustic pickup, 1.8 x 10 -2 fringe on a 10-ms time scale. The rise time is 45 μs. Stabilization against slow drifts in mirror distances is achieved by an electromechanically translated mirror driven by a servo system having a 0.2-s response time. A mechanical chopper in one of the two beam paths generates the signal which drives the servo system

Percolative Theory of Organic Magnetoresistance and Fringe-Field Magnetoresistance

Science.gov (United States)

Flatté, Michael E.

2013-03-01

A recently-introduced percolation theory for spin transport and magnetoresistance in organic semiconductors describes the effects of spin dynamics on hopping transport by considering changes in the effective density of hopping sites, a key quantity determining the properties of percolative transport. Increases in the spin-flip rate open up ``spin-blocked'' pathways to become viable conduction channels and hence, as the spin-flip rate changes with magnetic field, produce magnetoresistance. Features of this percolative magnetoresistance can be found analytically in several regimes, and agree with measurements of the shape and saturation of measured magnetoresistance curves. We find that the threshold hopping distance is analogous to the branching parameter of a phenomenological two-site model, and that the distinction between slow and fast hopping is contingent on the threshold hopping distance. Regimes of slow and fast hopping magnetoresistance are uniquely characterized by their line shapes. Studies of magnetoresistance in known systems with controllable positional disorder would provide an additional stringent test of this theory. Extensions to this theory also describe fringe-field magnetoresistance, which is the influence of fringe magnetic fields from a nearby unsaturated magnetic electrode on the conductance of an organic film. This theory agrees with several key features of the experimental fringe-field magnetoresistance, including the applied fields where the magnetoresistance reaches extrema, the applied field range of large magnetoresistance effects from the fringe fields, and the sign of the effect. All work done in collaboration with N. J. Harmon, and fringe-field magnetoresistance work in collaboration also with F. Macià, F. Wang, M. Wohlgenannt and A. D. Kent. This work was supported by an ARO MURI.

In-phase and anti-phase interference fringes in rocking curves of resonant X-ray dynamical diffraction

International Nuclear Information System (INIS)

Negishi, Riichirou; Fukamachi, Tomoe; Yoshizawa, Masami; Hirano, Kenji; Hirano, Keiichi; Kawamura, Takaaki

2008-01-01

We have observed the interference fringes that are in phase with each other in the diffracted and transmitted rocking curves of GaAs 200 reflection near the K-absorption edge of As. The fringes are in contrast with the well-known Pendelloesung fringes that are anti-phase with each other in the diffracted and transmitted waves. The origin of the in-phase interference fringe is analyzed to be due to the diffraction only by the imaginary part of the atomic scattering factor. It is also shown that the interference fringes become typical Pendelloesung fringes when the diffraction is caused only by the real part. (author)

Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms

International Nuclear Information System (INIS)

Volkov, V.V.; Han, M.G.; Zhu, Y.

2013-01-01

We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice. - Highlights: • We propose a fringe-shifting holographic method simple enough for practical implementations. • Our new image-wave-recovery algorithm follows from exact solution of holographic equations. • With autocorrelation band removal from holograms it is possible to achieve double-resolution electron holography data free from several commonly known artifacts. • The new fringe-shifting method can reach an image wave resolution close to single fringe spacing

Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms

Energy Technology Data Exchange (ETDEWEB)

Volkov, V.V., E-mail: volkov@bnl.gov; Han, M.G.; Zhu, Y.

2013-11-15

We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice. - Highlights: • We propose a fringe-shifting holographic method simple enough for practical implementations. • Our new image-wave-recovery algorithm follows from exact solution of holographic equations. • With autocorrelation band removal from holograms it is possible to achieve double-resolution electron holography data free from several commonly known artifacts. • The new fringe-shifting method can reach an image wave resolution close to single fringe spacing.

Controlling Fringe Sensitivity of Electro-Optic Holography Systems Using Laser Diode Current Modulation

Science.gov (United States)

Bybee, Shannon J.

2001-01-01

Electro-Optic Holography (EOH) is a non-intrusive, laser-based, displacement measurement technique capable of static and dynamic displacement measurements. EOH is an optical interference technique in which fringe patterns that represent displacement contour maps are generated. At excessively large displacements the fringe density may be so great that individual fringes are not resolvable using typical EOH techniques. This thesis focuses on the development and implementation of a method for controlling the sensitivity of the EOH system. This method is known as Frequency Translated Electro-Optic Holography (FTEOH). It was determined that by modulating the current source of the laser diode at integer multiples of the object vibration, the fringe pattern is governed by higher order Bessel function of the first kind and the number of fringes that represent a given displacement can be controlled. The reduction of fringes is theoretically unlimited but physically limited by the frequency bandwidth of the signal generator, providing modulation to the laser diode. Although this research technique has been verified theoretically and experimentally in this thesis, due to the current laser diode capabilities it is a tedious and time consuming process to acquire data using the FTEOH technique.

An improved principal component analysis based region matching method for fringe direction estimation

Science.gov (United States)

He, A.; Quan, C.

2018-04-01

The principal component analysis (PCA) and region matching combined method is effective for fringe direction estimation. However, its mask construction algorithm for region matching fails in some circumstances, and the algorithm for conversion of orientation to direction in mask areas is computationally-heavy and non-optimized. We propose an improved PCA based region matching method for the fringe direction estimation, which includes an improved and robust mask construction scheme, and a fast and optimized orientation-direction conversion algorithm for the mask areas. Along with the estimated fringe direction map, filtered fringe pattern by automatic selective reconstruction modification and enhanced fast empirical mode decomposition (ASRm-EFEMD) is used for Hilbert spiral transform (HST) to demodulate the phase. Subsequently, windowed Fourier ridge (WFR) method is used for the refinement of the phase. The robustness and effectiveness of proposed method are demonstrated by both simulated and experimental fringe patterns.

A generalization of the theory of fringe patterns containing displacement information

Science.gov (United States)

Sciammarella, C. A.; Bhat, G.

The theory that provides the interpretation of interferometric fringes as frequency modulated signals, is used to show that the electrooptical system used to analyze fringe patterns can be considered as a simultaneous Fourier spectrum analyzer. This interpretation generalizes the quasi-heterodyning techniques. It is pointed out that the same equations that yield the discrete Fourier transform as summations, yield correct values for a reduced number of steps. Examples of application of the proposed technique to electronic holography are given. It is found that for a uniform field the standard deviation of the individual readings is 1/20 of the fringe spacing.

Two dimensional Fourier transform methods for fringe pattern analysis

Science.gov (United States)

Sciammarella, C. A.; Bhat, G.

An overview of the use of FFTs for fringe pattern analysis is presented, with emphasis on fringe patterns containing displacement information. The techniques are illustrated via analysis of the displacement and strain distributions in the direction perpendicular to the loading, in a disk under diametral compression. The experimental strain distribution is compared to the theoretical, and the agreement is found to be excellent in regions where the elasticity solution models well the actual problem.

Effects of the Tax Treatment of Fringe Benefits on Labor Market Segmentation.

Science.gov (United States)

Scott, Frank A.; And Others

1989-01-01

Argues that the provision of the same fringe benefits for all workers promotes labor market segmentation by inducing workers to sort themselves across the economy according to their demand for fringe benefits. (JOW)

From Payday Loans To Pawnshops: Fringe Banking, The Unbanked, And Health.

Science.gov (United States)

Eisenberg-Guyot, Jerzy; Firth, Caislin; Klawitter, Marieka; Hajat, Anjum

2018-03-01

The fringe banking industry, including payday lenders and check cashers, was nearly nonexistent three decades ago. Today it generates tens of billions of dollars in annual revenue. The industry's growth accelerated in the 1980s with financial deregulation and the working class's declining resources. With Current Population Survey data, we used propensity score matching to investigate the relationship between fringe loan use, unbanked status, and self-rated health, hypothesizing that the material and stress effects of exposure to these financial services would be harmful to health. We found that fringe loan use was associated with 38 percent higher prevalence of poor or fair health, while being unbanked (not having one's own bank account) was associated with 17 percent higher prevalence. Although a variety of policies could mitigate the health consequences of these exposures, expanding social welfare programs and labor protections would address the root causes of the use of fringe services and advance health equity.

Effect of quadrupole fringe fields on the tune of Indus-2

International Nuclear Information System (INIS)

Kant, Pradeep; Husain, Riyasat; Ghodke, A.D.; Singh, Gurnam

2009-01-01

Being an unavoidable part in a real magnet design, fringe fields of different kind of magnets have various effects on the beam parameters of the storage ring. The fringe field of a bending magnet (dipole) generates closed orbit distortion and disturbs the dispersion function whereas the fringe field of a quadrupole affects other parameters of the ring like tune values and twiss functions. The fringe field pattern of the quadrupoles of Indus-2 was measured by the Magnet Group. The measurements were performed along the various radial tracks in a quadrupole from -30 to 30 mm in steps of 5 mm at various excitation current levels. The pattern of the gradient at these different current levels was obtained by a line fit of the magnetic field at each point. The data was used to get the effect on the tune of Indus-2. The paper describes the results of the effect on the tune. (author)

26 CFR 1.162-25T - Deductions with respect to noncash fringe benefits (temporary).

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Deductions with respect to noncash fringe... Individuals and Corporations § 1.162-25T Deductions with respect to noncash fringe benefits (temporary). (a) Employer. If an employer includes the value of a noncash fringe benefit in an employee's gross income, the...

Analysis of the Localization of Michelson Interferometer Fringes Using Fourier Optics and Temporal Coherence

Science.gov (United States)

Narayanamurthy, C. S.

2009-01-01

Fringes formed in a Michelson interferometer never localize in any plane, in the detector plane and in the localization plane. Instead, the fringes are assumed to localize at infinity. Except for some explanation in "Principles of Optics" by Born and Wolf (1964 (New York: Macmillan)), the fringe localization phenomena of Michelson's interferometer…

26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Taxation of fringe benefits-1985 through 1988 (temporary). 1.61-2T Section 1.61-2T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY..., and Taxable Income § 1.61-2T Taxation of fringe benefits—1985 through 1988 (temporary). (a) Fringe...

Phase and fringe order determination in wavelength scanning interferometry.

Science.gov (United States)

Moschetti, Giuseppe; Forbes, Alistair; Leach, Richard K; Jiang, Xiang; O'Connor, Daniel

2016-04-18

A method to obtain unambiguous surface height measurements using wavelength scanning interferometry with an improved repeatability, comparable to that obtainable using phase shifting interferometry, is reported. Rather than determining the conventional fringe frequency-derived z height directly, the method uses the frequency to resolve the fringe order ambiguity, and combine this information with the more accurate and repeatable fringe phase derived z height. A theoretical model to evaluate the method's performance in the presence of additive noise is derived and shown to be in good agreement with experiments. The measurement repeatability is improved by a factor of ten over that achieved when using frequency information alone, reaching the sub-nanometre range. Moreover, the z-axis non-linearity (bleed-through or ripple error) is reduced by a factor of ten. These order of magnitude improvements in measurement performance are demonstrated through a number of practical measurement examples.

Effective wavelength calibration for moire fringe projection

International Nuclear Information System (INIS)

Purcell, Daryl; Davies, Angela; Farahi, Faramarz

2006-01-01

The fringe patterns seen when using moire instruments are similar to the patterns seen in traditional interferometry but differ in the spacing between consecutive fringes. In traditional interferometry, the spacing is constant and related to the wavelength of the source. In moire fringe projection, the spacing (the effective wavelength) may not be constant over the field of view and the spacing depends on the system geometry. In these cases, using a constant effective wavelength over the field of view causes inaccurate surface height measurements. We examine the calibration process of the moirefringe projection measurement, which takes this varying wavelength into account to produce a pixel-by-pixel wavelength map. The wavelength calibration procedure is to move the object in the out-of-plane direction a known distance until every pixel intensity value goes through at least one cycle. A sinusoidal function is then fit to the data to extract the effective wavelength pixel by pixel, yielding an effective wavelength map. A calibrated step height was used to validate the effective wavelength map with results within 1% of the nominal value of the step height. The error sources that contributed to the uncertainty in determining the height of the artifact are also investigated

Inspection of arterial-induced skin vibration by Moire fringe with two-dimensional continuous wavelet transform

Science.gov (United States)

Wang, Chun-Hsiung; Chiu, Shih-Yung; Hsu, Yu-Hsiang; Lee, Shu-Sheng; Lee, Chih-Kung

2017-06-01

A non-contact arterial-induced skin vibration inspection system is implemented. This optical metrology system is constructed with shadow Moiré configuration and the fringe analysis algorithm. Developed with the Region of Interested (ROI) capturing technique and the Two-dimensional Wavelet Transform (2D-CWT) method, this algorithm is able to retrieve the height-correlated phase information from the shadow Moiré fringe patterns. Using a commercial video camera or a CMOS image sensor, this system could monitor the skin-vibration induced by the cyclic deformation of inner layered artery. The cross-sectional variation and the rhythm of heart cycle could be continuously measured for health monitoring purposes. The average vibration amplitude of the artery at the wrist ranges between 20 μm and 50 μm, which is quite subtle comparing with the skin surface structure. Having the non-stationary motion of human body, the traditional phase shifting (PS) technique can be very unstable due to the requirement of several frames of images, especially for case that artery is continuously pumping. To bypass this fundamental issue, the shadow Moiré technique is introduced to enhance the surface deformation characteristic. And the phase information is retrieved by the means of spectrum filtering instead of PS technique, which the phase is calculated from intensity maps of multiple images. The instantaneous surface can therefore be reconstructed individually from each frame, enabling the subtle arterial-induced skin vibration measurement. The comparative results of phase reconstruction between different fringe analysis algorithms will be demonstrated numerically and experimentally. And the electrocardiography (ECG) results will used as the reference for the validity of health monitoring potential of the non-contact arterial-induced skin vibration inspection system.

Telecentric 3D profilometry based on phase-shifting fringe projection.

Science.gov (United States)

Li, Dong; Liu, Chunyang; Tian, Jindong

2014-12-29

Three dimensional shape measurement in the microscopic range becomes increasingly important with the development of micro manufacturing technology. Microscopic fringe projection techniques offer a fast, robust, and full-field measurement for field sizes from approximately 1 mm2 to several cm2. However, the depth of field is very small due to the imaging of non-telecentric microscope, which is often not sufficient to measure the complete depth of a 3D-object. And the calibration of phase-to-depth conversion is complicated which need a precision translation stage and a reference plane. In this paper, we propose a novel telecentric phase-shifting projected fringe profilometry for small and thick objects. Telecentric imaging extends the depth of field approximately to millimeter order, which is much larger than that of microscopy. To avoid the complicated phase-to-depth conversion in microscopic fringe projection, we develop a new system calibration method of camera and projector based on telecentric imaging model. Based on these, a 3D reconstruction of telecentric imaging is presented with stereovision aided by fringe phase maps. Experiments demonstrated the feasibility and high measurement accuracy of the proposed system for thick object.

Design of an ozone and nitrogen dioxide sensor unit and its long-term operation within a sensor network in the city of Zurich

Directory of Open Access Journals (Sweden)

M. Mueller

2017-10-01

Full Text Available This study focuses on the investigation and quantification of low-cost sensor performance in application fields such as the extension of traditional air quality monitoring networks or the replacement of diffusion tubes. For this, sensor units consisting of two boxes featuring NO2 and O3 low-cost sensors and wireless data transfer were engineered. The sensor units were initially operated at air quality monitoring sites for 3 months for performance analysis and initial calibration. Afterwards, they were relocated and operated within a sensor network consisting of six locations for more than 1 year. Our analyses show that the employed O3 and NO2 sensors can be accurate to 2–5 and 5–7 ppb, respectively, during the first 3 months of operation. This accuracy, however, could not be maintained during their operation within the sensor network related to changes in sensor behaviour. For most of the O3 sensors a decrease in sensitivity was encountered over time, clearly impacting the data quality. The NO2 low-cost sensors in our configuration exhibited better performance but did not reach the accuracy level of NO2 diffusion tubes (∼ 2 ppb for uncorrected 14-day average concentrations. Tests in the laboratory revealed that changes in relative humidity can impact the signal of the employed NO2 sensors similarly to changes in ambient NO2 concentration. All the employed low-cost sensors need to be individually calibrated. Best performance of NO2 sensors is achieved when the calibration models also include time-dependent parameters accounting for changes in sensor response over time. Accordingly, an effective procedure for continuous data control and correction is essential for obtaining meaningful data. It is demonstrated that linking the measurements from low-cost sensors to the high-quality measurements from routine air quality monitoring stations is an effective procedure for both tasks provided that time periods can be identified when

Analysis of isoclinic fringes of a circular disk under diametric compression

International Nuclear Information System (INIS)

Jung, Girl; Park, Tae Geun; Yang, Min Bok; Kim, Myung Soo; Baek, Tae Hyun

2005-01-01

This paper presents the process for obtaining isoclinic fringes from experiment and compares the experimental results with theoretical calculations. In this experiment, the polaris cope named 'Stress master' is used as a primary tool, combined with a circular disk made of urethane rubber called as 'Photoflex' and a CCD camera to record the isoclinic fringes. In photoelasticity, isoclinics can be used to get the stress trajectories and then to analyze the whole field stresses. But it must be emphasized that isoclinic fringes are not themselves stress trajectories. In this paper, isoclinics are measured accurately by use of sharpening technique. Experimental results are comparable to those of theory.

A low-cost and portable realization on fringe projection three-dimensional measurement

Science.gov (United States)

Xiao, Suzhi; Tao, Wei; Zhao, Hui

2015-12-01

Fringe projection three-dimensional measurement is widely applied in a wide range of industrial application. The traditional fringe projection system has the disadvantages of high expense, big size, and complicated calibration requirements. In this paper we introduce a low-cost and portable realization on three-dimensional measurement with Pico projector. It has the advantages of low cost, compact physical size, and flexible configuration. For the proposed fringe projection system, there is no restriction to camera and projector's relative alignment on parallelism and perpendicularity for installation. Moreover, plane-based calibration method is adopted in this paper that avoids critical requirements on calibration system such as additional gauge block or precise linear z stage. What is more, error sources existing in the proposed system are introduced in this paper. The experimental results demonstrate the feasibility of the proposed low cost and portable fringe projection system.

Comparative analysis of gradient-field-based orientation estimation methods and regularized singular-value decomposition for fringe pattern processing.

Science.gov (United States)

Sun, Qi; Fu, Shujun

2017-09-20

Fringe orientation is an important feature of fringe patterns and has a wide range of applications such as guiding fringe pattern filtering, phase unwrapping, and abstraction. Estimating fringe orientation is a basic task for subsequent processing of fringe patterns. However, various noise, singular and obscure points, and orientation data degeneration lead to inaccurate calculations of fringe orientation. Thus, to deepen the understanding of orientation estimation and to better guide orientation estimation in fringe pattern processing, some advanced gradient-field-based orientation estimation methods are compared and analyzed. At the same time, following the ideas of smoothing regularization and computing of bigger gradient fields, a regularized singular-value decomposition (RSVD) technique is proposed for fringe orientation estimation. To compare the performance of these gradient-field-based methods, quantitative results and visual effect maps of orientation estimation are given on simulated and real fringe patterns that demonstrate that the RSVD produces the best estimation results at a cost of relatively less time.

Interpretation of interfacial structures in X-ray multilayers by TEM Fresnel fringe effects

OpenAIRE

Nguyen, Tai D.; O'Keefe, Michael A.; Kilaas, Roar; Gronsky, Ronald; Kortright, Jeffrey B.

1991-01-01

Assessment of interfacial structures from high-resolution TEM images of cross-sectional specimens is difficult due to Fresnel fringe effects producing different apparent structures in the images. The effects of these fringes have been commonly over-looked in efforts of making quantitative interpretation of interfacial profiles. In this report, we present the observations of the Fresnel fringes in nanometer period Mo/Si, W/C, and WC/C multilayers in through-focus-series TEM images. Calculation...

Modeling of the fringe shift in multiple beam interference for glass ...

Indian Academy of Sciences (India)

A quadratic model is suggested to describe the fringe shift occurred due to the phase variations of uncladded glass fiber introduced between the two plates of the liquid wedge interferometer. The fringe shift of the phase object is represented in the harmonic term which appears in the denominator of the Airy distribution ...

An analytical-numerical comprehensive method for optimizing the fringing magnetic field

International Nuclear Information System (INIS)

Xiao Meiqin; Mao Naifeng

1991-01-01

The criterion of optimizing the fringing magnetic field is discussed, and an analytical-numerical comprehensive method for realizing the optimization is introduced. The method mentioned above consists of two parts, the analytical part calculates the field of the shims, which corrects the fringing magnetic field by using uniform magnetizing method; the numerical part fulfils the whole calculation of the field distribution by solving the equation of magnetic vector potential A within the region covered by arbitrary triangular meshes with the aid of finite difference method and successive over relaxation method. On the basis of the method, the optimization of the fringing magnetic field for a large-scale electromagnetic isotope separator is finished

Second-order oriented partial-differential equations for denoising in electronic-speckle-pattern interferometry fringes.

Science.gov (United States)

Tang, Chen; Han, Lin; Ren, Hongwei; Zhou, Dongjian; Chang, Yiming; Wang, Xiaohang; Cui, Xiaolong

2008-10-01

We derive the second-order oriented partial-differential equations (PDEs) for denoising in electronic-speckle-pattern interferometry fringe patterns from two points of view. The first is based on variational methods, and the second is based on controlling diffusion direction. Our oriented PDE models make the diffusion along only the fringe orientation. The main advantage of our filtering method, based on oriented PDE models, is that it is very easy to implement compared with the published filtering methods along the fringe orientation. We demonstrate the performance of our oriented PDE models via application to two computer-simulated and experimentally obtained speckle fringes and compare with related PDE models.

Material Stress Fringe Constant Measurement of Specimen under Pure Bending Load by Use of Photoelastic Phase Shifting Method

International Nuclear Information System (INIS)

Liu, Guan Yong; Kim, Myung Soo; Baek, Tae Hyun

2014-01-01

In a photoelastic experiment, it is necessary to know the material stress fringe constant of the photoelastic specimen to determine the stresses from the measured isochromatic fringe orders. The material stress fringe constant can be obtained using a simple tension specimen and/or a circular disk under diametric compression. In these methods, there is generally a need to apply numerous loads to the specimen in response to the relationship of the fringe order. Then, the least squares method is used to obtain the material constant. In this paper, the fringe orders that appear on a four-point bending specimen are used to determine the fringe constant. This method requires four photoelastic fringes obtained from a circular polariscope by rotating the analyzer to 0, π/4, π/2, and 3π/4 radians. Using the four-point bending specimen to determine the material stress fringe constant has an advantage because measurements can be made at different locations by applying a constant load. The stress fringe constant measured with this method is within the range suggested by the manufacturer of the photoelastic material

Adaptive digital fringe projection technique for high dynamic range three-dimensional shape measurement.

Science.gov (United States)

Lin, Hui; Gao, Jian; Mei, Qing; He, Yunbo; Liu, Junxiu; Wang, Xingjin

2016-04-04

It is a challenge for any optical method to measure objects with a large range of reflectivity variation across the surface. Image saturation results in incorrect intensities in captured fringe pattern images, leading to phase and measurement errors. This paper presents a new adaptive digital fringe projection technique which avoids image saturation and has a high signal to noise ratio (SNR) in the three-dimensional (3-D) shape measurement of objects that has a large range of reflectivity variation across the surface. Compared to previous high dynamic range 3-D scan methods using many exposures and fringe pattern projections, which consumes a lot of time, the proposed technique uses only two preliminary steps of fringe pattern projection and image capture to generate the adapted fringe patterns, by adaptively adjusting the pixel-wise intensity of the projected fringe patterns based on the saturated pixels in the captured images of the surface being measured. For the bright regions due to high surface reflectivity and high illumination by the ambient light and surfaces interreflections, the projected intensity is reduced just to be low enough to avoid image saturation. Simultaneously, the maximum intensity of 255 is used for those dark regions with low surface reflectivity to maintain high SNR. Our experiments demonstrate that the proposed technique can achieve higher 3-D measurement accuracy across a surface with a large range of reflectivity variation.

Development of a phase counter with real-time fringe jump corrector for heterodyne interferometer on LHD

International Nuclear Information System (INIS)

Ito, Y.; Tanaka, K.; Tokuzawa, T.; Akiyama, T.; Okajima, S.; Kawahata, K.

2005-01-01

Phase counters, which are used with heterodyne interferometers for plasma density measurements, frequently suffer from phase jumping and cause difficulties for data interpretation. An automatic fringe jump corrector (AFJC) circuit has been developed to compensate for fringe jumps. The AFJC can correct phase jumps automatically in real-time. The AFJC, which is integrated on one chip, is installed on the presently working phase counter circuit. As for the specification of this phase counter the intermediate beat signal is 1 MHz, the phase detection range is 31 fringes with phase resolution of 1/80 of a fringe and the response time of 10 μs. The circuit has been tested on the far infrared (FIR) laser interferometer on LHD. The AFJC works fine to correct fringe jumps, when fringe jumps occurred due to the strong density gradient produced by the hydrogen pellet injection

26 CFR 1.132-6T - De minimis fringe-1985 through 1988 (temporary).

Science.gov (United States)

2010-04-01

... holiday gifts of property (not cash) with a low fair market value; occasional theatre or sporting event tickets; and coffee and doughnuts. (2) Benefits not excludable as de minimis fringes. Examples of fringe...

Distributed energy generation techniques and the competitive fringe effect in electricity markets

NARCIS (Netherlands)

Mulder, Machiel; Petrikaite, Vaiva; Scholtens, Bert

2015-01-01

We analyse the impact of two different generation techniques used by fringe suppliers on the intensity of competition in the electricity wholesale market. For that purpose, we derive a Cournot model of this market taking into account long-term contracts, international trade and fringe suppliers

Spatial Recognition of the Urban-Rural Fringe of Beijing Using DMSP/OLS Nighttime Light Data

Directory of Open Access Journals (Sweden)

Yuli Yang

2017-11-01

Full Text Available Spatial identification of the urban-rural fringes is very significant for deeply understanding the development processes and regulations of urban space and guiding urban spatial development in the future. Traditionally, urban-rural fringe areas are identified using statistical analysis methods that consider indexes from single or multiple factors, such as population densities, the ratio of building land, the proportion of the non-agricultural population, and economic levels. However, these methods have limitations, for example, the statistical data are not continuous, the statistical standards are not uniform, the data is seldom available in real time, and it is difficult to avoid issues on the statistical effects from edges of administrative regions or express the internal differences of these areas. This paper proposes a convenient approach to identify the urban-rural fringe using nighttime light data of DMSP/OLS images. First, a light characteristics–combined value model was built in ArcGIS 10.3, and the combined characteristics of light intensity and the degree of light intensity fluctuation are analyzed in the urban, urban-rural fringe, and rural areas. Then, the Python programming language was used to extract the breakpoints of the characteristic combination values of the nighttime light data in 360 directions taking Tian An Men as the center. Finally, the range of the urban-rural fringe area is identified. The results show that the urban-rural fringe of Beijing is mainly located in the annular band around Tian An Men. The average inner radius is 19 km, and the outer radius is 26 km. The urban-rural fringe includes the outer portions of the four city center districts, which are the Chaoyang District, Haidian District, Fengtai District, and Shijingshan District and the part area border with Daxing District, Tongzhou District, Changping District, Mentougou District, Shunyi District, and Fangshan District. The area of the urban-rural fringe

FIMBRIN1 is involved in lily pollen tube growth by stabilizing the actin fringe.

Science.gov (United States)

Su, Hui; Zhu, Jinsheng; Cai, Chao; Pei, Weike; Wang, Jiaojiao; Dong, Huaijian; Ren, Haiyun

2012-11-01

An actin fringe structure in the subapex plays an important role in pollen tube tip growth. However, the precise mechanism by which the actin fringe is generated and maintained remains largely unknown. Here, we cloned a 2606-bp full-length cDNA encoding a deduced 77-kD fimbrin-like protein from lily (Lilium longiflorum), named FIMBRIN1 (FIM1). Ll-FIM1 was preferentially expressed in pollen and concentrated at actin fringe in the subapical region, as well as in longitudinal actin-filament bundles in the shank of pollen tubes. Microinjection of Ll-FIM1 antibody into lily pollen tubes inhibited tip growth and disrupted the actin fringe. Furthermore, we verified the function of Ll-FIM1 in the fim5 mutant of its closest relative, Arabidopsis thaliana. Pollen tubes of fim5 mutants grew with a larger diameter in early stages but could recover into normal forms in later stages, despite significantly slower growth rates. The actin fringe of the fim5 mutants, however, was impaired during both early and late stages. Impressively, stable expression of fim5pro:GFP:Ll-FIM1 rescued the actin fringe and the growth rate of Arabidopsis fim5 pollen tubes. In vitro biochemical analysis showed that Ll-FIM1 could bundle actin filaments. Thus, our study has identified a fimbrin that may stabilize the actin fringe by cross-linking actin filaments into bundles, which is important for proper tip growth of lily pollen tubes.

45 CFR 86.56 - Fringe benefits.

Science.gov (United States)

2010-10-01

... available to employees or make fringe benefits available to spouses, families, or dependents of employees... Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION NONDISCRIMINATION ON THE BASIS OF..., accident, life insurance or retirement benefit, service, policy or plan, any profit-sharing or bonus plan...

Model-based multi-fringe interferometry using Zernike polynomials

Science.gov (United States)

Gu, Wei; Song, Weihong; Wu, Gaofeng; Quan, Haiyang; Wu, Yongqian; Zhao, Wenchuan

2018-06-01

In this paper, a general phase retrieval method is proposed, which is based on one single interferogram with a small amount of fringes (either tilt or power). Zernike polynomials are used to characterize the phase to be measured; the phase distribution is reconstructed by a non-linear least squares method. Experiments show that the proposed method can obtain satisfactory results compared to the standard phase-shifting interferometry technique. Additionally, the retrace errors of proposed method can be neglected because of the few fringes; it does not need any auxiliary phase shifting facilities (low cost) and it is easy to implement without the process of phase unwrapping.

A dual-mode proximity sensor with integrated capacitive and temperature sensing units

International Nuclear Information System (INIS)

Qiu, Shihua; Huang, Ying; He, Xiaoyue; Sun, Zhiguang; Liu, Ping; Liu, Caixia

2015-01-01

The proximity sensor is one of the most important devices in the field of robot application. It can accurately provide the proximity information to assistant robots to interact with human beings and the external environment safely. In this paper, we have proposed and demonstrated a dual-mode proximity sensor composed of capacitive and resistive sensing units. We defined the capacitive type proximity sensor perceiving the proximity information as C-mode and the resistive type proximity sensor detecting as R-mode. Graphene nanoplatelets (GNPs) were chosen as the R-mode sensing material because of its high performance. The dual-mode proximity sensor presents the following features: (1) the sensing distance of the dual-mode proximity sensor has been enlarged compared with the single capacitive proximity sensor in the same geometrical pattern; (2) experiments have verified that the proposed sensor can sense the proximity information of different materials; (3) the proximity sensing capability of the sensor has been improved by two modes perceive collaboratively, for a plastic block at a temperature of 60 °C: the R-mode will perceive the proximity information when the distance d between the sensor and object is 6.0–17.0 mm and the C-mode will do that when their interval is 0–2.0 mm; additionally two modes will work together when the distance is 2.0–6.0 mm. These features indicate our transducer is very valuable in skin-like sensing applications. (paper)

Color Fringe Correction by the Color Difference Prediction Using the Logistic Function.

Science.gov (United States)

Jang, Dong-Won; Park, Rae-Hong

2017-05-01

This paper proposes a new color fringe correction method that preserves the object color well by the color difference prediction using the logistic function. We observe two characteristics between normal edge (NE) and degraded edge (DE) due to color fringe: 1) the DE has relatively smaller R-G and B-G correlations than the NE and 2) the color difference in the NE can be fitted by the logistic function. The proposed method adjusts the color difference of the DE to the logistic function by maximizing the R-G and B-G correlations in the corrected color fringe image. The generalized logistic function with four parameters requires a high computational load to select the optimal parameters. In experiments, a one-parameter optimization can correct color fringe gracefully with a reduced computational load. Experimental results show that the proposed method restores well the original object color in the DE, whereas existing methods give monochromatic or distorted color.

An optoelectronic system for fringe pattern analysis

Science.gov (United States)

Sciammarella, C. A.; Ahmadshahi, M.

A system capable of retrieving and processing information recorded in fringe patterns is reported. The principal components are described as well as the architecture in which they are assembled. An example of application is given.

Investigation on the intense fringe formation phenomenon downstream hot-image plane.

Science.gov (United States)

Hu, Yonghua; Li, Guohui; Zhang, Lifu; Huang, Wenti; Chen, Shuming

2015-11-30

The propagation of a high-power flat-topped Gaussian beam, which is modulated by three parallel wirelike scatterers, passing through a downstream Kerr medium slab and free spaces is investigated. A new phenomenon is found that a kind of intense fringe with intensity several times that of the incident beam can be formed in a plane downstream the Kerr medium. This kind of intense fringe is another result in the propagation process of nonlinear imaging and it locates scores of centimeters downstream the predicted hot image plane. Moreover, the intensity of this fringe can achieve the magnitude of that of hot image in corresponding single-scatterer case, and this phenomenon can arise only under certain conditions. As for the corresponding hot images, they are also formed but largely suppressed. The cause of the formation of such an intense fringe is analyzed and found related to interference in the free space downstream the Kerr medium. Moreover, the ways it is influenced by some important factors such as the wavelength of incident beam and the properties of scatterers and Kerr medium are discussed, and some important properties and relations are revealed.

3D fingerprint imaging system based on full-field fringe projection profilometry

Science.gov (United States)

Huang, Shujun; Zhang, Zonghua; Zhao, Yan; Dai, Jie; Chen, Chao; Xu, Yongjia; Zhang, E.; Xie, Lili

2014-01-01

As an unique, unchangeable and easily acquired biometrics, fingerprint has been widely studied in academics and applied in many fields over the years. The traditional fingerprint recognition methods are based on the obtained 2D feature of fingerprint. However, fingerprint is a 3D biological characteristic. The mapping from 3D to 2D loses 1D information and causes nonlinear distortion of the captured fingerprint. Therefore, it is becoming more and more important to obtain 3D fingerprint information for recognition. In this paper, a novel 3D fingerprint imaging system is presented based on fringe projection technique to obtain 3D features and the corresponding color texture information. A series of color sinusoidal fringe patterns with optimum three-fringe numbers are projected onto a finger surface. From another viewpoint, the fringe patterns are deformed by the finger surface and captured by a CCD camera. 3D shape data of the finger can be obtained from the captured fringe pattern images. This paper studies the prototype of the 3D fingerprint imaging system, including principle of 3D fingerprint acquisition, hardware design of the 3D imaging system, 3D calibration of the system, and software development. Some experiments are carried out by acquiring several 3D fingerprint data. The experimental results demonstrate the feasibility of the proposed 3D fingerprint imaging system.

3-D optical profilometry at micron scale with multi-frequency fringe projection using modified fibre optic Lloyd's mirror technique

Science.gov (United States)

Inanç, Arda; Kösoğlu, Gülşen; Yüksel, Heba; Naci Inci, Mehmet

2018-06-01

A new fibre optic Lloyd's mirror method is developed for extracting 3-D height distribution of various objects at the micron scale with a resolution of 4 μm. The fibre optic assembly is elegantly integrated to an optical microscope and a CCD camera. It is demonstrated that the proposed technique is quite suitable and practical to produce an interference pattern with an adjustable frequency. By increasing the distance between the fibre and the mirror with a micrometre stage in the Lloyd's mirror assembly, the separation between the two bright fringes is lowered down to the micron scale without using any additional elements as part of the optical projection unit. A fibre optic cable, whose polymer jacket is partially stripped, and a microfluidic channel are used as test objects to extract their surface topographies. Point by point sensitivity of the method is found to be around 8 μm, changing a couple of microns depending on the fringe frequency and the measured height. A straightforward calibration procedure for the phase to height conversion is also introduced by making use of the vertical moving stage of the optical microscope. The phase analysis of the acquired image is carried out by One Dimensional Continuous Wavelet Transform for which the chosen wavelet is the Morlet wavelet and the carrier removal of the projected fringe patterns is achieved by reference subtraction. Furthermore, flexible multi-frequency property of the proposed method allows measuring discontinuous heights where there are phase ambiguities like 2π by lowering the fringe frequency and eliminating the phase ambiguity.

Turbo machine tip clearance and vibration measurements using a fibre optic laser Doppler position sensor

Science.gov (United States)

Pfister, T.; Büttner, L.; Czarske, J.; Krain, H.; Schodl, R.

2006-07-01

This paper presents a novel fibre optic laser Doppler position sensor for single blade tip clearance and vibration measurements at turbo machines, which offers high temporal resolution and high position resolution simultaneously. The sensor principle is based on the generation of a measurement volume consisting of two superposed fan-like interference fringe systems with contrary fringe spacing gradients using wavelength division multiplexing. A flexible and robust measurement system with an all-passive fibre coupled measurement head has been realized employing diffractive and refractive optics. Measurements of tip clearance and rotor vibrations at a transonic centrifugal compressor performed during operation at up to 50 000 rpm (833 Hz) corresponding to 21.7 kHz blade frequency and 586 m s-1 blade tip velocity are presented. The results are in excellent agreement with those of capacitive probes. The mean uncertainty of the position measurement was around 20 µm and, thus, considerably better than for conventional tip clearance probes. Consequently, this sensor is capable of fulfilling the requirements for future active clearance control systems and has great potential for in situ and online tip clearance and vibration measurements at metallic and non-metallic turbine blades with high precision.

Ultrafast layer based computer-generated hologram calculation with sparse template holographic fringe pattern for 3-D object.

Science.gov (United States)

Kim, Hak Gu; Man Ro, Yong

2017-11-27

In this paper, we propose a new ultrafast layer based CGH calculation that exploits the sparsity of hologram fringe pattern in 3-D object layer. Specifically, we devise a sparse template holographic fringe pattern. The holographic fringe pattern on a depth layer can be rapidly calculated by adding the sparse template holographic fringe patterns at each object point position. Since the size of sparse template holographic fringe pattern is much smaller than that of the CGH plane, the computational load can be significantly reduced. Experimental results show that the proposed method achieves 10-20 msec for 1024x1024 pixels providing visually plausible results.

Stitching interferometry of high numerical aperture cylindrical optics without using a fringe-nulling routine.

Science.gov (United States)

Peng, Junzheng; Wang, Qingquan; Peng, Xiang; Yu, Yingjie

2015-11-01

Stitching interferometry is a common method for measuring the figure error of high numerical aperture optics. However, subaperture measurement usually requires a fringe-nulling routine, thus making the stitching procedure complex and time-consuming. The challenge when measuring a surface without a fringe-nulling routine is that the rays no longer perpendicularly hit the surface. This violation of the null-test condition can lead to high fringe density and introduce high-order misalignment aberrations into the measurement result. This paper demonstrates that the high-order misalignment aberrations can be characterized by low-order misalignment aberrations; then, an efficient method is proposed to separate the high-order misalignment aberrations from subaperture data. With the proposed method, the fringe-nulling routine is not required. Instead, the subaperture data is measured under a nonzero fringe pattern. Then, all possible misalignment aberrations are removed with the proposed method. Finally, the full aperture map is acquired by connecting all subaperture data together. Experimental results showing the feasibility of the proposed procedure are presented.

Study of 3D solder-paste profilometer by dual digital fringe projection

Science.gov (United States)

Juan, Yi-Hua; Yih, Jeng-Nan; Cheng, Nai-Jen

2013-09-01

In a 3D profilometer by the fringe projection, the shadow will be produced inevitably, thus the fringes cannot be detected in the region of the shadow. In addition, a smooth surface or a metal surface produces the specular reflection, and then, no projection fringe can be recorded in the region of oversaturation on CCD. This paper reveals a proposed system for improved these defects and shows some preliminary improved 3D profiles by the proposed dual fringe projection. To obtain the profile of sample hided in the shadow and the oversaturation, this study used the dual-projection system by two projectors. This system adopted two different directions of fringe projection and illuminates them alternately, therefore, the shadow and the oversaturation produced in their corresponding locations. Two raw 3D profiles obtained from taking the dual-projection by the four-step phase-shift. A set of algorithms used to identify the pixels of the shadow and the oversaturation, and create an error-map. According to the error-map to compensate, two 3D profiles merged into an error-reduced 3D profile. We used the solder paste as a testing sample. After comparatively analyzing the 3D images obtained by our measurement system and by a contact stylus profilometer, the result shows that our measurement system can effectively reduce the error caused by shadows and oversaturation. Fringe projection system by using a projector is a non-contact, full field and quickly measuring system. The proposed dual-projection by dual-projectors can effectively reduce the shadow and the oversaturation errors and enhance the scope of application of the 3D contour detection, especially in the detection of precision structure parts with specular reflection.

Robust and efficient multi-frequency temporal phase unwrapping: optimal fringe frequency and pattern sequence selection.

Science.gov (United States)

Zhang, Minliang; Chen, Qian; Tao, Tianyang; Feng, Shijie; Hu, Yan; Li, Hui; Zuo, Chao

2017-08-21

Temporal phase unwrapping (TPU) is an essential algorithm in fringe projection profilometry (FPP), especially when measuring complex objects with discontinuities and isolated surfaces. Among others, the multi-frequency TPU has been proven to be the most reliable algorithm in the presence of noise. For a practical FPP system, in order to achieve an accurate, efficient, and reliable measurement, one needs to make wise choices about three key experimental parameters: the highest fringe frequency, the phase-shifting steps, and the fringe pattern sequence. However, there was very little research on how to optimize these parameters quantitatively, especially considering all three aspects from a theoretical and analytical perspective simultaneously. In this work, we propose a new scheme to determine simultaneously the optimal fringe frequency, phase-shifting steps and pattern sequence under multi-frequency TPU, robustly achieving high accuracy measurement by a minimum number of fringe frames. Firstly, noise models regarding phase-shifting algorithms as well as 3-D coordinates are established under a projector defocusing condition, which leads to the optimal highest fringe frequency for a FPP system. Then, a new concept termed frequency-to-frame ratio (FFR) that evaluates the magnitude of the contribution of each frame for TPU is defined, on which an optimal phase-shifting combination scheme is proposed. Finally, a judgment criterion is established, which can be used to judge whether the ratio between adjacent fringe frequencies is conducive to stably and efficiently unwrapping the phase. The proposed method provides a simple and effective theoretical framework to improve the accuracy, efficiency, and robustness of a practical FPP system in actual measurement conditions. The correctness of the derived models as well as the validity of the proposed schemes have been verified through extensive simulations and experiments. Based on a normal monocular 3-D FPP hardware system

20 CFR 641.873 - What minimum expenditure levels are required for participant wages and fringe benefits?

Science.gov (United States)

2010-04-01

... for participant wages and fringe benefits? 641.873 Section 641.873 Employees' Benefits EMPLOYMENT AND... wages and fringe benefits? (a) Not less than 75 percent of the SCSEP funds provided under a grant from the Department must be used to pay for the wages and fringe benefits of participants in such projects...

Optimal multi-photon phase sensing with a single interference fringe

Science.gov (United States)

Xiang, G. Y.; Hofmann, H. F.; Pryde, G. J.

2013-01-01

Quantum entanglement can help to increase the precision of optical phase measurements beyond the shot noise limit (SNL) to the ultimate Heisenberg limit. However, the N-photon parity measurements required to achieve this optimal sensitivity are extremely difficult to realize with current photon detection technologies, requiring high-fidelity resolution of N + 1 different photon distributions between the output ports. Recent experimental demonstrations of precision beyond the SNL have therefore used only one or two photon-number detection patterns instead of parity measurements. Here we investigate the achievable phase sensitivity of the simple and efficient single interference fringe detection technique. We show that the maximally-entangled “NOON” state does not achieve optimal phase sensitivity when N > 4, rather, we show that the Holland-Burnett state is optimal. We experimentally demonstrate this enhanced sensitivity using a single photon-counted fringe of the six-photon Holland-Burnett state. Specifically, our single-fringe six-photon measurement achieves a phase variance three times below the SNL. PMID:24067490

Utilization characteristics and importance of woody biomass resources on the rural-urban fringe in botswana.

Science.gov (United States)

Nkambwe, Musisi; Sekhwela, Mogodisheng B M

2006-02-01

This article examines the utilization characteristics and importance of woody biomass resources in the rural-urban fringe zones of Botswana. In the literature for Africa, attention has been given to the availability and utilization of biomass in either urban or rural environments, but the rural-urban fringe has been neglected. Within southern Africa, this neglect is not justified; the rural-urban fringe, not getting the full benefits available in urban environments in Botswana, has developed problems in woody biomass availability and utilization that require close attention. In this article, socioeconomic data on the importance of woody biomass in the Batlokwa Tribal Territory, on the rural-urban fringe of Gaborone, Botswana, were collected together with ecologic data that reveal the utilization characteristics and potential for regrowth of woody biomass. The analysis of these results show that local woody biomass is very important in the daily lives of communities in the rural-urban fringe zones and that there is a high level of harvesting. However, there is no effort in planning land use in the tribal territory to either conserve this resource or provide alternatives to its utilization. The future of woody biomass resources in Botswana's rural-urban fringe is uncertain. The investigators recommend that a comprehensive policy for the development of the rural-urban fringe consider the importance of this resource. The neglect of this resource will have far-reaching implications on the livelihoods of residents as well as the environment in this zone.

Adaptive enhancement of optical fringe patterns by selective reconstruction using FABEMD algorithm and Hilbert spiral transform.

Science.gov (United States)

Trusiak, Maciej; Patorski, Krzysztof; Wielgus, Maciej

2012-10-08

Presented method for fringe pattern enhancement has been designed for processing and analyzing low quality fringe patterns. It uses a modified fast and adaptive bidimensional empirical mode decomposition (FABEMD) for the extraction of bidimensional intrinsic mode functions (BIMFs) from an interferogram. Fringe pattern is then selectively reconstructed (SR) taking the regions of selected BIMFs with high modulation values only. Amplitude demodulation and normalization of the reconstructed image is conducted using the spiral phase Hilbert transform (HS). It has been tested using computer generated interferograms and real data. The performance of the presented SR-FABEMD-HS method is compared with other normalization techniques. Its superiority, potential and robustness to high fringe density variations and the presence of noise, modulation and background illumination defects in analyzed fringe patterns has been corroborated.

3D phase-shifting fringe projection system on the basis of a tailored free-form mirror.

Science.gov (United States)

Zwick, Susanne; Heist, Stefan; Steinkopf, Ralf; Huber, Sandra; Krause, Sylvio; Bräuer-Burchardt, Christian; Kühmstedt, Peter; Notni, Gunther

2013-05-10

Phase-shifting fringe projection is an effective method to perform 3D shape measurements. Conventionally, fringe projection systems utilize a digital projector that images fringes into the measurement plane. The performance of such systems is limited to the visible spectral range, as most projectors experience technical limitations in UV or IR spectral ranges. However, for certain applications these spectral ranges are of special interest. We present a wideband fringe projector that has been developed on the basis of a picture generating beamshaping mirror. This mirror generates a sinusoidal fringe pattern in the measurement plane without any additional optical elements. Phase shifting is realized without any mechanical movement by a multichip LED. As the system is based on a single mirror, it is wavelength-independent in a wide spectral range and therefore applicable in UV and IR spectral ranges. We present the design and a realized setup of this fringe projection system and the characterization of the generated intensity distribution. Experimental results of 3D shape measurements are presented.

A second-order approximation of particle motion in the fringing field of a dipole magnet

International Nuclear Information System (INIS)

Tarantin, N.I.

1980-01-01

The radial and axial motion of charged particles in the fringing field of an arbitrary dipole magnet has been considered with accuracy to the second-order of small quantities. The dipole magnet has an inhomogeneous field and oblique entrance and exit boundaries in the form of second-order curves. The region of the fringing field has a variable extension. A new definition of the effective boundary of the real fringing field has a variable extension. A new definition of the effective boundary of the real fringing field of the dipole magnet is used. A better understanding of the influence of the fringing magnetic field on the motion of charged particles in the pole gap of the dipole magnet has been obtained. In particular, it is shown that it is important to take into account, in the second approximation, some terms related formally to the next approximations. The results are presented in a form convenient for practical calculations. (orig.)

Fringe proteins modulate Notch-ligand cis and trans interactions to specify signaling states.

Science.gov (United States)

LeBon, Lauren; Lee, Tom V; Sprinzak, David; Jafar-Nejad, Hamed; Elowitz, Michael B

2014-09-25

The Notch signaling pathway consists of multiple types of receptors and ligands, whose interactions can be tuned by Fringe glycosyltransferases. A major challenge is to determine how these components control the specificity and directionality of Notch signaling in developmental contexts. Here, we analyzed same-cell (cis) Notch-ligand interactions for Notch1, Dll1, and Jag1, and their dependence on Fringe protein expression in mammalian cells. We found that Dll1 and Jag1 can cis-inhibit Notch1, and Fringe proteins modulate these interactions in a way that parallels their effects on trans interactions. Fringe similarly modulated Notch-ligand cis interactions during Drosophila development. Based on these and previously identified interactions, we show how the design of the Notch signaling pathway leads to a restricted repertoire of signaling states that promote heterotypic signaling between distinct cell types, providing insight into the design principles of the Notch signaling system, and the specific developmental process of Drosophila dorsal-ventral boundary formation.

Nitrogen dynamics in subtropical fringe and basin mangrove forests inferred from stable isotopes.

Science.gov (United States)

Reis, Carla Roberta Gonçalves; Nardoto, Gabriela Bielefeld; Rochelle, André Luis Casarin; Vieira, Simone Aparecida; Oliveira, Rafael Silva

2017-03-01

Mangroves exhibit low species richness compared to other tropical forests, but great structural and functional diversity. Aiming to contribute to a better understanding of the functioning of mangrove forests, we investigated nitrogen (N) dynamics in two physiographic types of mangroves (fringe and basin forests) in southeastern Brazil. Because fringe forests are under great influence of tidal flushing we hypothesized that these forests would exhibit higher N cycling rates in sediment and higher N losses to the atmosphere compared to basin forests. We quantified net N mineralization and nitrification rates in sediment and natural abundance of N stable isotopes (δ 15 N) in the sediment-plant-litter system. The fringe forest exhibited higher net N mineralization rates and δ 15 N in the sediment-plant-litter system, but net nitrification rates were similar to those of the basin forest. The results of the present study suggest that fringe forests exhibit higher N availability and N cycling in sediment compared to basin forests.

Advanced split-illumination electron holography without Fresnel fringes

International Nuclear Information System (INIS)

Tanigaki, Toshiaki; Aizawa, Shinji; Park, Hyun Soon; Matsuda, Tsuyoshi; Harada, Ken; Shindo, Daisuke

2014-01-01

Advanced split-illumination electron holography was developed by employing two biprisms in the illuminating system to split an electron wave into two coherent waves and two biprisms in the imaging system to overlap them. A focused image of an upper condenser-biprism filament was formed on the sample plane, and all other filaments were placed in its shadow. This developed system makes it possible to obtain precise reconstructed object waves without modulations due to Fresnel fringes, in addition to holograms of distant objects from reference waves. - Highlights: • Advanced split-illumination electron holography without Fresnel fringes is developed. • Two biprisms are installed in illuminating system of microscope. • High-precision holographic observations of an area locating far from the sample edge become possible

Advanced split-illumination electron holography without Fresnel fringes

Energy Technology Data Exchange (ETDEWEB)

Tanigaki, Toshiaki, E-mail: tanigaki-toshiaki@riken.jp [Center for Emergent Matter Science (CEMS), RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Aizawa, Shinji; Park, Hyun Soon [Center for Emergent Matter Science (CEMS), RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Matsuda, Tsuyoshi [Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Harada, Ken [Central Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395 (Japan); Shindo, Daisuke [Center for Emergent Matter Science (CEMS), RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan)

2014-02-01

Advanced split-illumination electron holography was developed by employing two biprisms in the illuminating system to split an electron wave into two coherent waves and two biprisms in the imaging system to overlap them. A focused image of an upper condenser-biprism filament was formed on the sample plane, and all other filaments were placed in its shadow. This developed system makes it possible to obtain precise reconstructed object waves without modulations due to Fresnel fringes, in addition to holograms of distant objects from reference waves. - Highlights: • Advanced split-illumination electron holography without Fresnel fringes is developed. • Two biprisms are installed in illuminating system of microscope. • High-precision holographic observations of an area locating far from the sample edge become possible.

Three-dimensional shape profiling by out-of-focus projection of colored pulse width modulation fringe patterns.

Science.gov (United States)

Silva, Adriana; Flores, Jorge L; Muñoz, Antonio; Ayubi, Gastón A; Ferrari, José A

2017-06-20

Three-dimensional (3D) shape profiling by sinusoidal phase-shifting methods is affected by the non-linearity of the projector. To overcome this problem, the defocusing technique has become an important alternative to generate sinusoidal fringe patterns. The precision of this method depends on the binary pattern used and on the defocusing applied. To improve the defocusing technique, we propose the implementation of a color-based binary fringe patterns. The proposed technique involves the generation of colored pulse width modulation (PWM) fringe patterns, which are generated with different frequencies at the carrier signal. From an adequate selection of these frequencies, the colored PWM fringe patterns will lead to amplitude harmonics lower than the conventional PWM fringe patterns. Hence, the defocusing can decrease, and the 3D shape profiling can be more accurate. Numerical simulations and experimental results are presented as validation.

Fringing field optimization of hemispherical deflector analyzers using BEM and FDM

Energy Technology Data Exchange (ETDEWEB)

Sise, Omer, E-mail: omersise@aku.edu.t [Department of Physics, Science and Arts Faculty, Afyon Kocatepe University, 03200 Afyonkarahisar (Turkey); Ulu, Melike; Dogan, Mevlut [Department of Physics, Science and Arts Faculty, Afyon Kocatepe University, 03200 Afyonkarahisar (Turkey); Martinez, Genoveva [Department Fisica Aplicada III, Fac. de Fisica, UCM 28040-Madrid (Spain); Zouros, Theo J.M. [Department of Physics, University of Crete, P.O. Box 2208, 71003 Heraklion, Crete (Greece); TANDEM Accelerator Laboratory, Institute of Nuclear Physics, NCSR ' Demokritos' , 153.10 Aghia Paraskevi, Athens (Greece)

2010-02-15

In this paper we present numerical modeling results for fringing field optimization of hemispherical deflector analyzers (HDAs), simulated using boundary-element and finite-difference numerical methods. Optimization of the fringing field aberrations of HDAs is performed by using a biased optical axis and an optimized entry position offset (paracentric) from the center position used in conventional HDAs. The described optimization achieves first-order focusing thus also further improving the energy resolution of HDAs.

FFT swept filtering: a bias-free method for processing fringe signals in absolute gravimeters

Science.gov (United States)

Křen, Petr; Pálinkáš, Vojtech; Mašika, Pavel; Val'ko, Miloš

2018-05-01

Absolute gravimeters, based on laser interferometry, are widely used for many applications in geoscience and metrology. Although currently the most accurate FG5 and FG5X gravimeters declare standard uncertainties at the level of 2-3 μGal, their inherent systematic errors affect the gravity reference determined by international key comparisons based predominately on the use of FG5-type instruments. The measurement results for FG5-215 and FG5X-251 clearly showed that the measured g-values depend on the size of the fringe signal and that this effect might be approximated by a linear regression with a slope of up to 0.030 μGal/mV . However, these empirical results do not enable one to identify the source of the effect or to determine a reasonable reference fringe level for correcting g-values in an absolute sense. Therefore, both gravimeters were equipped with new measuring systems (according to Křen et al. in Metrologia 53:27-40, 2016. https://doi.org/10.1088/0026-1394/53/1/27 applied for FG5), running in parallel with the original systems. The new systems use an analogue-to-digital converter HS5 to digitize the fringe signal and a new method of fringe signal analysis based on FFT swept bandpass filtering. We demonstrate that the source of the fringe size effect is connected to a distortion of the fringe signal due to the electronic components used in the FG5(X) gravimeters. To obtain a bias-free g-value, the FFT swept method should be applied for the determination of zero-crossings. A comparison of g-values obtained from the new and the original systems clearly shows that the original system might be biased by approximately 3-5 μGal due to improperly distorted fringe signal processing.

Taking apart the enhanced backscattering cone: Interference fringes from reciprocal paths in multiple light scattering

International Nuclear Information System (INIS)

Bret, Boris P. J.; Ferreira, Flavio P.; Nunes-Pereira, Eduardo J.; Belsley, Michael

2010-01-01

We report the decomposition of the enhanced backscattering cone into its constitutive interference fringes. These fringes are due to the constructive interference between reciprocal paths of any multiply scattered wave after ensemble averaging. An optical setup combining a two-point continuous-wave illumination and matching detection allows the observation of the fringes and, therefore, the quantitative characterization of the Green's function for light propagation between the two points in a multiple-scattering media.

The linkage between car-related fringe benefits and the travel behavior of knowledge workers

DEFF Research Database (Denmark)

Bendit, Eduard; Frenkel, Amnon; Kaplan, Sigal

2011-01-01

This study focuses on the linkage between car-related fringe benefits and the travel behavior of knowledge workers in commute and leisure trips. Specifically, this study compares the commuting and leisure travel behavior of knowledge workers who receive either a company-car or car allowance...... with the travel behavior of workers who do not receive car-related fringe benefits. Data are based on a revealed-preferences survey among knowledge workers in Israel. Results show that car-related fringe benefits are associated with (i) high car ownership and car use intensity, (ii) long commute distances...... and travel times and non-sustainable transport modes, and (iii) high frequency of long-distance leisure trips. Policy implications include (i) directing policies towards reducing car ownership induced by car-related fringe benefits, (ii) encouraging company-car holders to ‘pay their way’, and (iii...

Analysis of moiré fringes by Wiener filtering: An extension to the Fourier method

International Nuclear Information System (INIS)

Harasse, Sébastien; Yashiro, Wataru; Momose, Atsushi

2012-01-01

In X-ray Talbot interferometry, tilting the phase grating with respect to the absorption grating results in the formation of spatial fringes. The analysis of this moiré pattern, classically performed by the Fourier method, allows the extraction of the sample phase shift information from a single image. In this context, an extension to the Fourier method is proposed. The filter used to extract the fringe information is chosen optimally in the least-squares sense, given models for the zeroth and first order modes, noise and the modulation transfer function. The latter is obtained by measuring the detector response to moiré fringes with increasing frequencies. The obtained Wiener filter allows a better reconstruction of the phase information at all fringe frequencies, compared to the usual box or gaussian filters. This is demonstrated quantitatively by experiments using synchrotron radiation.

3D palmprint and hand imaging system based on full-field composite color sinusoidal fringe projection technique.

Science.gov (United States)

Zhang, Zonghua; Huang, Shujun; Xu, Yongjia; Chen, Chao; Zhao, Yan; Gao, Nan; Xiao, Yanjun

2013-09-01

Palmprint and hand shape, as two kinds of important biometric characteristics, have been widely studied and applied to human identity recognition. The existing research is based mainly on 2D images, which lose the third-dimensional information. The biological features extracted from 2D images are distorted by pressure and rolling, so the subsequent feature matching and recognition are inaccurate. This paper presents a method to acquire accurate 3D shapes of palmprint and hand by projecting full-field composite color sinusoidal fringe patterns and the corresponding color texture information. A 3D imaging system is designed to capture and process the full-field composite color fringe patterns on hand surface. Composite color fringe patterns having the optimum three fringe numbers are generated by software and projected onto the surface of human hand by a digital light processing projector. From another viewpoint, a color CCD camera captures the deformed fringe patterns and saves them for postprocessing. After compensating for the cross talk and chromatic aberration between color channels, three fringe patterns are extracted from three color channels of a captured composite color image. Wrapped phase information can be calculated from the sinusoidal fringe patterns with high precision. At the same time, the absolute phase of each pixel is determined by the optimum three-fringe selection method. After building up the relationship between absolute phase map and 3D shape data, the 3D palmprint and hand are obtained. Color texture information can be directly captured or demodulated from the captured composite fringe pattern images. Experimental results show that the proposed method and system can yield accurate 3D shape and color texture information of the palmprint and hand shape.

The effects of noise-bandwidth, noise-fringe duration, and temporal signal location on the binaural masking-level difference.

Science.gov (United States)

Yasin, Ifat; Henning, G Bruce

2012-07-01

The effects of forward and backward noise fringes on binaural signal detectability were investigated. Masked thresholds for a 12-ms, 250-Hz, sinusoidal signal masked by Gaussian noise, centered at 250 Hz, with bandwidths from 3 to 201 Hz, were obtained in N(0)S(0) and N(0)S(π) configurations. The signal was (a) temporally centered in a 12-ms noise burst (no fringe), (b) presented at the start of a 600-ms noise burst (backward fringe), or (c) temporally centered in a 600-ms noise burst (forward-plus-backward fringe). For noise bandwidths between 3 and 75 Hz, detection in N(0)S(0) improved with the addition of a backward fringe, improving further with an additional forward fringe; there was little improvement in N(0)S(π). The binaural masking-level difference (BMLD) increased from 0 to 8 dB with a forward-plus-backward fringe as noise bandwidths increased to 100 Hz, increasing slightly to 10 dB at 201 Hz. This two-stage increase was less pronounced with a backward fringe. With no fringe, the BMLD was about 10-14 dB at all bandwidths. Performance appears to result from the interaction of across-time and across-frequency listening strategies and the possible effects of gain reduction and suppression, which combine in complex ways. Current binaural models are, as yet, unable to account fully for these effects.

DLP-based 3D metrology by structured light or projected fringe technology for life sciences and industrial metrology

Science.gov (United States)

Frankowski, G.; Hainich, R.

2009-02-01

Since the mid-eighties, a fundamental idea for achieving measuring accuracy in projected fringe technology was to consider the projected fringe pattern as an interferogram and evaluate it on the basis of advanced algorithms widely used for phase measuring in real-time interferometry. A fundamental requirement for obtaining a sufficiently high degree of measuring accuracy with this so-called "phase measuring projected fringe technology" is that the projected fringes, analogous to interference fringes, must have a cos2-shaped intensity distribution. Until the mid-nineties, this requirement for the projected fringe pattern measurement technology presented a basic handicap for its wide application in 3D metrology. This situation changed abruptly, when in the nineties Texas Instruments introduced to the market advanced digital light projection on the basis of micro mirror based projection systems, socalled DLP technology, which also facilitated the generation and projection of cos2-shaped intensity and/or fringe patterns. With this DLP technology, which from its original approach was actually oriented towards completely different applications such as multimedia projection, Texas Instruments boosted phase-measuring fringe projection in optical 3D metrology to a worldwide breakthrough both for medical as well as industrial applications. A subject matter of the lecture will be to present the fundamental principles and the resulting advantages of optical 3D metrology based on phase-measuring fringe projection using DLP technology. Further will be presented and discussed applications of the measurement technology in medical engineering and industrial metrology.

Fringe projection profilometry with portable consumer devices

Science.gov (United States)

Liu, Danji; Pan, Zhipeng; Wu, Yuxiang; Yue, Huimin

2018-01-01

A fringe projection profilometry (FPP) using portable consumer devices is attractive because it can realize optical three dimensional (3D) measurement for ordinary consumers in their daily lives. We demonstrate a FPP using a camera in a smart mobile phone and a digital consumer mini projector. In our experiment of testing the smart phone (iphone7) camera performance, the rare-facing camera in the iphone7 causes the FPP to have a fringe contrast ratio of 0.546, nonlinear carrier phase aberration value of 0.6 rad, and nonlinear phase error of 0.08 rad and RMS random phase error of 0.033 rad. In contrast, the FPP using the industrial camera has a fringe contrast ratio of 0.715, nonlinear carrier phase aberration value of 0.5 rad, nonlinear phase error of 0.05 rad and RMS random phase error of 0.011 rad. Good performance is achieved by using the FPP composed of an iphone7 and a mini projector. 3D information of a facemask with a size for an adult is also measured by using the FPP that uses portable consumer devices. After the system calibration, the 3D absolute information of the facemask is obtained. The measured results are in good agreement with the ones that are carried out in a traditional way. Our results show that it is possible to use portable consumer devices to construct a good FPP, which is useful for ordinary people to get 3D information in their daily lives.

Geographically distributed environmental sensor system

Science.gov (United States)

French, Patrick; Veatch, Brad; O'Connor, Mike

2006-10-03

The present invention is directed to a sensor network that includes a number of sensor units and a base unit. The base station operates in a network discovery mode (in which network topology information is collected) in a data polling mode (in which sensed information is collected from selected sensory units). Each of the sensor units can include a number of features, including an anemometer, a rain gauge, a compass, a GPS receiver, a barometric pressure sensor, an air temperature sensor, a humidity sensor, a level, and a radiant temperature sensor.

Community structure and abundance of benthic infaunal invertebrates in Maine fringing marsh ecosystems

Science.gov (United States)

Richard A. MacKenzie; Michele Dionne; Jeremy Miller; Michael Haas; Pamela A. Morgan

2015-01-01

Fringing marshes are abundant ecosystems that dominate the New England coastline. Despite their abundance, very little baseline data is available from them and few studies have documented the ecosystems services that they provide. This information is important for conservation efforts as well as for an increased understanding of how fringing marshes function compared...

Commuting-related fringe benefits in the Netherlands : Interrelationships and company, employee and location characteristics

NARCIS (Netherlands)

Nijland, Linda; Dijst, Martin

2015-01-01

Mobility management measures taken by firms could potentially result in more sustainable transport choices and hence reduce traffic congestion and emissions. Fringe benefits offered to employees are a means to implement those measures. This paper explores the most common commuting-related fringe

High-speed scanning stroboscopic fringe-pattern projection technology for three-dimensional shape precision measurement.

Science.gov (United States)

Yang, Guowei; Sun, Changku; Wang, Peng; Xu, Yixin

2014-01-10

A high-speed scanning stroboscopic fringe-pattern projection system is designed. A high-speed rotating polygon mirror and a line-structured laser cooperate to produce stable and unambiguous stroboscopic fringe patterns. The system combines the rapidity of the grating projection with the high accuracy of the line-structured laser light source. The fringe patterns have fast frame rate, great density, high precision, and high brightness, with convenience and accuracy in adjusting brightness, frequency, linewidth, and the amount of phase shift. The characteristics and the stability of this system are verified by experiments. Experimental results show that the finest linewidth can reach 40 μm and that the minimum fringe cycle is 80 μm. Circuit modulation makes the light source system flexibly adjustable, easy to control in real time, and convenient to project various fringe patterns. Combined with different light intensity adjustment algorithms and 3D computation models, the 3D topography with high accuracy can be obtained for objects measured under different environments or objects with different sizes, morphologies, and optical properties. The proposed system shows a broad application prospect for fast 3D shape precision measurements, particularly in the industrial field of 3D online detection for precision devices.

Stress Analysis of an Edge-Cracked Plate by using Photoelastic Fringe Phase Shifting Method

International Nuclear Information System (INIS)

Baek, Tae Hyun; Kim, Myung Soo; Cho, Sung Ho

2000-01-01

The method of photoelasticity allows one to obtain principal stress differences and principal stress directions in a photoelastic model. In the classical approach, the photoelastic parameters are measured manually point by point. The previous methods require much time and skill in the identification and measurement of photoelastic data. Fringe phase shifting method has been recently developed and widely used to measure and analyze fringe data in photo-mechanics. This paper presents the test results of photoelastic fringe phase shifting technique for the stress analysis of a circular disk under compression and an edge-cracked plate subjected to tensile load. The technique used here requires four phase stepped photoelastic images obtained from a circular polariscope by rotating the analyzer at 0 .deg. ,45 .deg. ,90 .deg. ,and 135 .deg. . Experimental results are compared with those or FEM. Good agreement between the results can be observed. However, some error may be included if the technique is used to general direction which is not parallel to isoclinic fringe

29 CFR 4.1b - Payment of minimum compensation based on collectively bargained wage rates and fringe benefits...

Science.gov (United States)

2010-07-01

... bargained wage rates and fringe benefits applicable to employment under predecessor contract. 4.1b Section 4... collectively bargained wage rates and fringe benefits applicable to employment under predecessor contract. (a) Section 4(c) of the Service Contract Act of 1965 as amended provides special minimum wage and fringe...

Research on a power management system for thermoelectric generators to drive wireless sensors on a spindle unit.

Science.gov (United States)

Li, Sheng; Yao, Xinhua; Fu, Jianzhong

2014-07-16

Thermoelectric energy harvesting is emerging as a promising alternative energy source to drive wireless sensors in mechanical systems. Typically, the waste heat from spindle units in machine tools creates potential for thermoelectric generation. However, the problem of low and fluctuant ambient temperature differences in spindle units limits the application of thermoelectric generation to drive a wireless sensor. This study is devoted to presenting a transformer-based power management system and its associated control strategy to make the wireless sensor work stably at different speeds of the spindle. The charging/discharging time of capacitors is optimized through this energy-harvesting strategy. A rotating spindle platform is set up to test the performance of the power management system at different speeds. The experimental results show that a longer sampling cycle time will increase the stability of the wireless sensor. The experiments also prove that utilizing the optimal time can make the power management system work more effectively compared with other systems using the same sample cycle.

Adaptive DFT-Based Interferometer Fringe Tracking

Science.gov (United States)

Wilson, Edward; Pedretti, Ettore; Bregman, Jesse; Mah, Robert W.; Traub, Wesley A.

2005-12-01

An automatic interferometer fringe tracking system has been developed, implemented, and tested at the Infrared Optical Telescope Array (IOTA) Observatory at Mount Hopkins, Arizona. The system can minimize the optical path differences (OPDs) for all three baselines of the Michelson stellar interferometer at IOTA. Based on sliding window discrete Fourier-transform (DFT) calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on offline data. Implemented in ANSI C on the 266 MHz PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately [InlineEquation not available: see fulltext.] milliseconds per scan (including all three interferograms), using the science camera and piezo scanners to measure and correct the OPDs. The adaptive DFT-based tracking algorithm should be applicable to other systems where there is a need to detect or track a signal with an approximately constant-frequency carrier pulse. One example of such an application might be to the field of thin-film measurement by ellipsometry, using a broadband light source and a Fourier-transform spectrometer to detect the resulting fringe patterns.

Adaptive DFT-Based Interferometer Fringe Tracking

Directory of Open Access Journals (Sweden)

Wesley A. Traub

2005-09-01

Full Text Available An automatic interferometer fringe tracking system has been developed, implemented, and tested at the Infrared Optical Telescope Array (IOTA Observatory at Mount Hopkins, Arizona. The system can minimize the optical path differences (OPDs for all three baselines of the Michelson stellar interferometer at IOTA. Based on sliding window discrete Fourier-transform (DFT calculations that were optimized for computational efficiency and robustness to atmospheric disturbances, the algorithm has also been tested extensively on offline data. Implemented in ANSI C on the 266 MHz PowerPC processor running the VxWorks real-time operating system, the algorithm runs in approximately 2.0 milliseconds per scan (including all three interferograms, using the science camera and piezo scanners to measure and correct the OPDs. The adaptive DFT-based tracking algorithm should be applicable to other systems where there is a need to detect or track a signal with an approximately constant-frequency carrier pulse. One example of such an application might be to the field of thin-film measurement by ellipsometry, using a broadband light source and a Fourier-transform spectrometer to detect the resulting fringe patterns.

Digital reconstruction of Young's fringes using Fresnel transformation

Science.gov (United States)

Kulenovic, Rudi; Song, Yaozu; Renninger, P.; Groll, Manfred

1997-11-01

This paper deals with the digital numerical reconstruction of Young's fringes from laser speckle photography by means of the Fresnel-transformation. The physical model of the optical reconstruction of a specklegram is a near-field Fresnel-diffraction phenomenon which can be mathematically described by the Fresnel-transformation. Therefore, the interference phenomena can be directly calculated by a microcomputer.If additional a CCD-camera is used for specklegram recording the measurement procedure and evaluation process can be completely carried out in a digital way. Compared with conventional laser speckle photography no holographic plates, no wet development process and no optical specklegram reconstruction are needed. These advantages reveal a wide future in scientific and engineering applications. The basic principle of the numerical reconstruction is described, the effects of experimental parameters of Young's fringes are analyzed and representative results are presented.

Speckle and fringe dynamics in imagingspeckle-pattern interferometry for spatial-filtering velocimetry

DEFF Research Database (Denmark)

Jakobsen, Michael Linde; Iversen, Theis F. Q.; Yura, Harold T.

2011-01-01

This paper analyzes the dynamics of laser speckles and fringes, formed in an imaging-speckle-pattern interferometer with the purpose of sensing linear three-dimensional motion and out-of-plane components of rotation in real time, using optical spatial-filtering-velocimetry techniques. The ensemble......-average definition of the cross-correlation function is applied to the intensity distributions, obtained in the observation plane at two positions of the object. The theoretical analysis provides a description for the dynamics of both the speckles and the fringes. The analysis reveals that both the magnitude...... and direction of all three linear displacement components of the object movement can be determined. Simultaneously, out-ofplane rotation of the object including the corresponding directions can be determined from the spatial gradient of the in-plane fringe motion throughout the observation plane. The theory...

Inherently safe SNR shutdown system with Curie point controlled sensor/switch unit

International Nuclear Information System (INIS)

Mueller, K.; Norajitra, P.; Reiser, H.

1987-02-01

Inherent shutdown due to increase in the sodium temperature at the core outlet is triggered by interruption of the current supply to the electromagnet coupling of absorber elements via curie point controlled sensor/switch units. These switches are arranged above suitable fuel element positions and spatially independent of the shutdown elements. Compared with other similar systems very short response times are achieved. A prototype switch unit has already undergone extensive testing. These tests have confirmed that switching takes place in a very narrow temperature range. (orig./HP) [de

Comment on "Fringe projection profilometry with nonparallel illumination: a least-squares approach"

Science.gov (United States)

Wang, Zhaoyang; Bi, Hongbo

2006-07-01

We comment on the recent Letter by Chen and Quan [Opt. Lett.30, 2101 (2005)] in which a least-squares approach was proposed to cope with the nonparallel illumination in fringe projection profilometry. It is noted that the previous mathematical derivations of the fringe pitch and carrier phase functions on the reference plane were incorrect. In addition, we suggest that the variation of carrier phase along the vertical direction should be considered.

Delineating Urban Fringe Area by Land Cover Information Entropy—An Empirical Study of Guangzhou-Foshan Metropolitan Area, China

Directory of Open Access Journals (Sweden)

Junyi Huang

2016-05-01

Full Text Available Rapid urbanization has caused many environmental problems, such as the heat island effect, intensifying air pollution, pollution from runoff, loss of wildlife habitat, etc. Accurate evaluations of these problems demand an accurate delineation of the spatial extent of the urban fringe. Conceptual and analytical ambiguity of the urban fringe and a general lack of consensus among researchers have made its measurement very difficult. This study reports a compound and reliable method to delineate the urban fringe area using a case study. Based on the 'fringe effect' theory in landscape ecology, the existing land cover information entropy model for defining the urban fringe is renewed by incorporating scale theory, cartography and urban geography theory. Results show that the urban fringe area of Guangzhou and Foshan metropolitan area covers an area of 2031 km2, and it occupies over 31% of the total study area. Result evaluation by industry structure data shows satisfactory correspondence with different land cover types. This paper reports the method and outcome of an attempt to provide an objective, repeatable and generally applicable method for mapping its spatial extent from remote sensing imageries, and could be beneficial to relevant urban studies and urban fringe management projects.

Fringe Fitting for Coherent Integrations with the NPOI

National Research Council Canada - National Science Library

Jorgensen, A. M; Mozurkewich, D; Armstrong, T; Hindsley, R; Pauls, T; Gilbreath, G. Charmaine; Restaino, S

2004-01-01

...), which is based on fitting a model fringe pattern to the NPOI data frames. The procedure is quite computationally intensive, but gives a better estimation of the phase than the conventional method of locating the peak of the group delay power...

Simplified paraboloid phase model-based phase tracker for demodulation of a single complex fringe.

Science.gov (United States)

He, A; Deepan, B; Quan, C

2017-09-01

A regularized phase tracker (RPT) is an effective method for demodulation of single closed-fringe patterns. However, lengthy calculation time, specially designed scanning strategy, and sign-ambiguity problems caused by noise and saddle points reduce its effectiveness, especially for demodulating large and complex fringe patterns. In this paper, a simplified paraboloid phase model-based regularized phase tracker (SPRPT) is proposed. In SPRPT, first and second phase derivatives are pre-determined by the density-direction-combined method and discrete higher-order demodulation algorithm, respectively. Hence, cost function is effectively simplified to reduce the computation time significantly. Moreover, pre-determined phase derivatives improve the robustness of the demodulation of closed, complex fringe patterns. Thus, no specifically designed scanning strategy is needed; nevertheless, it is robust against the sign-ambiguity problem. The paraboloid phase model also assures better accuracy and robustness against noise. Both the simulated and experimental fringe patterns (obtained using electronic speckle pattern interferometry) are used to validate the proposed method, and a comparison of the proposed method with existing RPT methods is carried out. The simulation results show that the proposed method has achieved the highest accuracy with less computational time. The experimental result proves the robustness and the accuracy of the proposed method for demodulation of noisy fringe patterns and its feasibility for static and dynamic applications.

FIMBRIN1 Is Involved in Lily Pollen Tube Growth by Stabilizing the Actin Fringe[C][W][OA

Science.gov (United States)

Su, Hui; Zhu, Jinsheng; Cai, Chao; Pei, Weike; Wang, Jiaojiao; Dong, Huaijian; Ren, Haiyun

2012-01-01

An actin fringe structure in the subapex plays an important role in pollen tube tip growth. However, the precise mechanism by which the actin fringe is generated and maintained remains largely unknown. Here, we cloned a 2606-bp full-length cDNA encoding a deduced 77-kD fimbrin-like protein from lily (Lilium longiflorum), named FIMBRIN1 (FIM1). Ll-FIM1 was preferentially expressed in pollen and concentrated at actin fringe in the subapical region, as well as in longitudinal actin-filament bundles in the shank of pollen tubes. Microinjection of Ll-FIM1 antibody into lily pollen tubes inhibited tip growth and disrupted the actin fringe. Furthermore, we verified the function of Ll-FIM1 in the fim5 mutant of its closest relative, Arabidopsis thaliana. Pollen tubes of fim5 mutants grew with a larger diameter in early stages but could recover into normal forms in later stages, despite significantly slower growth rates. The actin fringe of the fim5 mutants, however, was impaired during both early and late stages. Impressively, stable expression of fim5pro:GFP:Ll-FIM1 rescued the actin fringe and the growth rate of Arabidopsis fim5 pollen tubes. In vitro biochemical analysis showed that Ll-FIM1 could bundle actin filaments. Thus, our study has identified a fimbrin that may stabilize the actin fringe by cross-linking actin filaments into bundles, which is important for proper tip growth of lily pollen tubes. PMID:23150633

Fringe projection application for surface variation analysis on helical shaped silicon breast

Science.gov (United States)

Vairavan, R.; Ong, N. R.; Sauli, Z.; Shahimin, M. M.; Kirtsaeng, S.; Sakuntasathien, S.; Alcain, J. B.; Paitong, P.; Retnasamy, V.

2017-09-01

Breast carcinoma is rated as a second collective cause of cancer associated death among adult females. Detection of the disease at an early stage would enhance the chance for survival. Established detection methods such as mammography, ultrasound and MRI are classified as non invasive breast cancer detection modality, but however they are not entire non-invasive as physical contact still occurs to the breast. Thus requirement for a complete non invasive and non contact is evident. Therefore, in this work, a novel application of digital fringe projection for early detection of breast cancer based on breast surface analysis is reported. Phase shift fringe projection technique and pixel tracing method was utilized to analyze the breast surface change due to the incidence of breast lump. Results have shown that the digital fringe projection is capable in detecting the existence of 1 cm sized lump within the breast sample.

Resolving fringe ambiguities of a wide-field Michelson interferometer using visibility measurements of a noncollimated laser beam.

Science.gov (United States)

Wan, Xiaoke; Wang, Ji; Ge, Jian

2009-09-10

An actively stabilized interferometer with a constant optical path difference is a key element in long-term astronomical observation, and resolving interference fringe ambiguities is important to produce high-precision results for the long term. We report a simple and reliable method of resolving fringe ambiguities of a wide-field Michelson interferometer by measuring the interference visibility of a noncollimated single-frequency laser beam. Theoretical analysis shows that the interference visibility is sensitive to a subfringe phase shift, and a wide range of beam arrangements is suitable for real implementation. In an experimental demonstration, a Michelson interferometer has an optical path difference of 7 mm and a converging monitoring beam has a numerical aperture of 0.045 with an incidental angle of 17 degrees. The resolution of visibility measurements corresponds to approximately 1/16 fringe in the interferometer phase shift. The fringe ambiguity-free region is extended over a range of approximately 100 fringes.

Adaptive oriented PDEs filtering methods based on new controlling speed function for discontinuous optical fringe patterns

Science.gov (United States)

Zhou, Qiuling; Tang, Chen; Li, Biyuan; Wang, Linlin; Lei, Zhenkun; Tang, Shuwei

2018-01-01

The filtering of discontinuous optical fringe patterns is a challenging problem faced in this area. This paper is concerned with oriented partial differential equations (OPDEs)-based image filtering methods for discontinuous optical fringe patterns. We redefine a new controlling speed function to depend on the orientation coherence. The orientation coherence can be used to distinguish the continuous regions and the discontinuous regions, and can be calculated by utilizing fringe orientation. We introduce the new controlling speed function to the previous OPDEs and propose adaptive OPDEs filtering models. According to our proposed adaptive OPDEs filtering models, the filtering in the continuous and discontinuous regions can be selectively carried out. We demonstrate the performance of the proposed adaptive OPDEs via application to the simulated and experimental fringe patterns, and compare our methods with the previous OPDEs.

Singlet-to-triplet interconversion using hyperfine as well as ferromagnetic fringe fields.

Science.gov (United States)

Wohlgenannt, M; Flatté, M E; Harmon, N J; Wang, F; Kent, A D; Macià, F

2015-06-28

Until recently the important role that spin-physics ('spintronics') plays in organic light-emitting devices and photovoltaic cells was not sufficiently recognized. This attitude has begun to change. We review our recent work that shows that spatially rapidly varying local magnetic fields that may be present in the organic layer dramatically affect electronic transport properties and electroluminescence efficiency. Competition between spin-dynamics due to these spatially varying fields and an applied, spatially homogeneous magnetic field leads to large magnetoresistance, even at room temperature where the thermodynamic influences of the resulting nuclear and electronic Zeeman splittings are negligible. Spatially rapidly varying local magnetic fields are naturally present in many organic materials in the form of nuclear hyperfine fields, but we will also review a second method of controlling the electrical conductivity/electroluminescence, using the spatially varying magnetic fringe fields of a magnetically unsaturated ferromagnet. Fringe-field magnetoresistance has a magnitude of several per cent and is hysteretic and anisotropic. This new method of control is sensitive to even remanent magnetic states, leading to different conductivity/electroluminescence values in the absence of an applied field. We briefly review a model based on fringe-field-induced polaron-pair spin-dynamics that successfully describes several key features of the experimental fringe-field magnetoresistance and magnetoelectroluminescence. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Biodegradation at Dynamic Plume Fringes: Mixing Versus Reaction Control

Science.gov (United States)

Cirpka, O. A.; Eckert, D.; Griebler, C.; Haberer, C.; Kürzinger, P.; Bauer, R.; Mellage, A.

2014-12-01

Biodegradation of continuously emitted plumes is known to be most pronounced at the plume fringe, where mixing of contaminated water and ambient groundwater, containing dissolved electron acceptors, stimulates microbial activity. Under steady-state conditions, physical mixing of contaminant and electron acceptor by transverse dispersion was shown to be the major bottleneck for biodegradation, with plume lengths scaling inversely with the bulk transverse dispersivity in quasi two-dimensional settings. Under these conditions, the presence of suitable microbes is essential but the biokinetic parameters do not play an important role. When the location of the plume shifts (caused, e.g., by a fluctuating groundwater table), however, the bacteria are no more situated at the plume fringe and biomass growth, decay, activation and deactivation determine the time lag until the fringe-controlled steady state is approached again. During this time lag, degradation is incomplete. The objective of the presented study was to analyze to which extent flow and transport dynamics diminish effectiveness of fringe-controlled biodegradation and which microbial processes and related biokinetic parameters determine the system response in overall degradation to hydraulic fluctuations. We performed experiments in quasi-two-dimensional flow through microcosms on aerobic toluene degradation by Pseudomonas putida F1. Plume dynamics were simulated by vertical alteration of the toluene plume position and experimental results were analyzed by reactive-transport modeling. We found that, even after disappearance of the toluene plume for two weeks, the majority of microorganisms stayed attached to the sediment and regained their full biodegradation potential within two days after reappearance of the toluene plume. Our results underline that besides microbial growth and maintenance (often subsumed as "biomass decay") microbial dormancy (that is, change into a metabolically inactive state) and

Confessions of an iconoclast: at home on the fringe.

Science.gov (United States)

Loevinger, Jane

2002-04-01

The career of a psychologist whose work has been on the fringe of psychometrics, of personality theory, and, at a stretch, of psychoanalytic theory and the philosophy of science is described in this article.

Coherent Integrations, Fringe Modeling, and Bootstrapping With the NPOI

National Research Council Canada - National Science Library

Jorgensen, Anders M; Mozurkewich, Dave; Schmitt, Henrique; Armstrong, J. T; Gilbreath, G. C; Hindsley, Robert; Pauls, Thomas A; Peterson, Deane M

2006-01-01

.... It causes fringes to move on ms time-scales, forcing very short exposures. Because of the semi-random phase shifts, the traditional approach averages exposure power spectra to build signal-to-noise ratio (SNR...

The Offerings of Fringe Figures and Migrants

Science.gov (United States)

Engels-Schwarzpaul, A.-Chr.

2015-01-01

"The Western tradition", as passe-partout, includes fringe figures, émigrés and migrants. Rather than looking to resources at the core of the Western tradition to overcome its own blindnesses, I am more interested in its gaps and peripheries, where other thoughts and renegade knowledges take hold. It is in the contact zones with…

Urban fringe renewal with urban catalysts elements: connections in an unconnected area

OpenAIRE

Yanru, Yang

2014-01-01

Based on Santa Coloma as a main case,analyzing how can be update there in this crisis situation to do suitable interventions to achieve a great effect. After analyzing the Santa Coloma area,I pay attention to its urban marginality.It has the territorial marginality,the marginality of the relationship with Barcelona,the marginality of the people and life style and so on. Urban fringe is corresponding the city center, the city of mainstream.The socalled "fringe" can be underst...

Self-correction of projector nonlinearity in phase-shifting fringe projection profilometry.

Science.gov (United States)

Lü, Fuxing; Xing, Shuo; Guo, Hongwei

2017-09-01

In phase-shifting fringe projection profilometry, the luminance nonlinearity of the used projector has been recognized as one of the most crucial factors decreasing the measurement accuracy. To solve this problem, this paper presents a self-correcting technique that allows us to suppress the effect of the projector nonlinearity in the absence of any calibration data regarding the projector intensities or regarding the phase errors. In its first step, the standard phase-shifting algorithm is used to recover the phases, as well as the background intensities and the modulations. Using these results enables normalizing the fringe patterns, for ridding them of the effects of the background and modulations. Second, we smooth the calculated phase map by use of a low-pass filter in order to remove the ripple-like phase errors induced by the projector nonlinearity. Third, we determine a polynomial representing the projector nonlinearity by fitting the curve of the normalized fringe intensities against the cosine values of the smoothed phases. Finally, we correct the phase errors using the curve just obtained. Doing these steps in an iterative way eventually results in a phase map and, further, a 3D shape with their artifacts induced by the projector nonlinearity suppressed significantly. Experimental results demonstrate that this technique offers some advantages over others. It does not require a prior calibration of the projector, thus being suitable for dealing with a time-variant nonlinearity; its pointwise operation protects the edges and details of the measurement results from being blurred; and it works well with very few fringe patterns and is efficient in image capturing.

APPLICATION FEATURES OF SPATIAL CONDUCTOMETRY SENSORS IN MODELLING OF COOLANT FLOW MIXING IN NUCLEAR POWER UNIT EQUIPMENT

Directory of Open Access Journals (Sweden)

A. A. Barinov

2016-01-01

Full Text Available Coolant flow mixing processes with different temperatures and concentrations of diluted additives widely known in nuclear power units operation. In some cases these processes make essential impact on the resource and behavior of the nuclear unit during transient and emergency situations. The aim of the study was creation of measurement system and test facility to carry out basic tests and to embed spatial conductometry method in investigation practice of turbulent coolant flows. In the course of investigation measurement system with sensors and experimental facility was designed, several first tests were carried out. A special attention was dedicated to calibration and clarification of conductometry sensor application methodologies in studies of turbulent flow characteristics. Investigations involved method of electrically contrast tracer jet with concurrent flow in closed channel of round crosssection. The measurements include both averaged and unsteady realizations of measurement signal. Experimental data processing shows good agreement with other tests acquired from another measurement systems based on different physical principles. Calibration functions were acquired, methodical basis of spatial conductometry measurement system application was created. Gathered experience of spatial sensor application made it possible to formulate the principles of further investigation that involve large-scale models of nuclear unit equipment. Spatial wire-mesh sensors proved to be a perspective type of eddy resolving measurement devices.

Theoretical study of the properties of X-ray diffraction moiré fringes. I

International Nuclear Information System (INIS)

Yoshimura, Jun-ichi

2015-01-01

A detailed and comprehensive theoretical description of X-ray diffraction moiré fringes for a bicrystal specimen is given on the basis of a calculation by plane-wave dynamical diffraction theory, where the effect of the Pendellösung intensity oscillation on the moiré pattern is explained in detail. A detailed and comprehensive theoretical description of X-ray diffraction moiré fringes for a bicrystal specimen is given on the basis of a calculation by plane-wave dynamical diffraction theory. Firstly, prior to discussing the main subject of the paper, a previous article [Yoshimura (1997 ▸). Acta Cryst. A53, 810–812] on the two-dimensionality of diffraction moiré patterns is restated on a thorough calculation of the moiré interference phase. Then, the properties of moiré fringes derived from the above theory are explained for the case of a plane-wave diffraction image, where the significant effect of Pendellösung intensity oscillation on the moiré pattern when the crystal is strained is described in detail with theoretically simulated moiré images. Although such plane-wave moiré images are not widely observed in a nearly pure form, knowledge of their properties is essential for the understanding of diffraction moiré fringes in general

High-speed X-ray phase tomography with Talbot interferometer and fringe scanning method

International Nuclear Information System (INIS)

Kibayashi, Shunsuke; Harasse, Sébastien; Yashiro, Wataru; Momose, Atsushi

2012-01-01

High-speed X-ray phase tomography based on the Fourier-transform method has been demonstrated with an X-ray Talbot interferometer using white synchrotron radiation. We report the experimental results of high-speed X-ray phase tomography with fringe-scanning method instead of Fourier-transform method to improve spatial resolution without a considerable increase of scan time. To apply fringe-scanning method to high speed tomography, we tested a scan that is a synchronous combination of one-way continuous movements of the sample rotation and the grating displacement. When this scanning method was combined with X-ray phase tomography, we were able to obtain a scan time of 5 s. A comparison of the image quality derived with the conventional approach and with the proposed approach using the fringe-scanning method showed that the latter had better spatial resolution.

Fringe periods of color moirés in contact-type 3-D displays.

Science.gov (United States)

Lee, Hyoung; Kim, Sung-Kyu; Sohn, Kwanghoon; Son, Jung-Young; Chernyshov, Oleksii O

2016-06-27

A mathematical formula of calculating the fringe periods of the color moirés appearing at the contact-type 3-D displays is derived. It is typical that the color moirés are chirped and the period of the line pattern in viewing zone forming optics is more than two times of that of the pixel pattern in the display panel. These make impossible to calculate the fringe periods of the color moirés with the conventional beat frequency formula. The derived formula work very well for any combination of two line patterns having either a same line period or different line periods. This is experimentally proved. Furthermore, it is also shown that the fringe period can be expressed in terms of the viewing distance and focal length of the viewing zone forming optics.

The effect of geographical centralization of education for outmigration from fringe areas

DEFF Research Database (Denmark)

Andersen, Hans Skifter

During the last 25 years population in fringe areas in Denmark has declined. The main reason has been that young people leave these areas and seldom come back. In this study is examined the connection between young people’s outmigration, their choice of education and the location of educational...... institutions. It is shown that geographical centralization of education since 1990 and the tendency for more young people to choose higher education has resulted in an increase in the outmigration of young people from fringe areas...

Modeling of Dipole and Quadrupole Fringe-Field Effects for the Advanced Photon Source Upgrade Lattice

Energy Technology Data Exchange (ETDEWEB)

Borland, M.; Lindberg, R.

2017-06-01

The proposed upgrade of the Advanced Photon Source (APS) to a multibend-achromat lattice requires shorter and much stronger quadrupole magnets than are present in the existing ring. This results in longitudinal gradient profiles that differ significantly from a hard-edge model. Additionally, the lattice assumes the use of five-segment longitudinal gradient dipoles. Under these circumstances, the effects of fringe fields and detailed field distributions are of interest. We evaluated the effect of soft-edge fringe fields on the linear optics and chromaticity, finding that compensation for these effects is readily accomplished. In addition, we evaluated the reliability of standard methods of simulating hardedge nonlinear fringe effects in quadrupoles.

Fringe Controls Naïve CD4+T Cells Differentiation through Modulating Notch Signaling in Asthmatic Rat Models

Science.gov (United States)

Gu, Wen; Xu, Weiguo; Ding, Tao; Guo, Xuejun

2012-01-01

The ability of Notch signaling to regulate T helper cell development and differentiation has been widely accepted. Fringe, O-fucose-β1,3-N-acetylglucosaminyltransferases modulate Notch receptor expression and promote the Notch signaling pathway through receptor-ligand binding. In this study, we assayed the expression levels of three Fringe homologs in naive CD4+T cells in asthmatic rats. We found that Radical Fringe (Rfng) was highly expressed, whereas both Lunatic Fringe (Lfng) and Manic Fringe (Mfng) were expressed at low levels. Down-regulation of Rfng using siRNA, and overexpression of Lfng or Mfng enhanced Th1 subset lineages and diminished Th2 subset lineages. Notch signaling was more activated in asthmatic naïve CD4+T cells than in control cells, and Lfng, but not Mfng or Rfng, partly inhibited Notch signaling in asthmatic naïve CD4+T lymphocytes. Lfng overexpression resulted in significantly decreased Th2 cytokine production in asthma, which was the same effect as the GSI (γ-secretase inhibitor) treatment alone, but had an increased effect on Th1 cytokines than GSI treatment. Collectively, these data identify the essential role of Fringe modulating naïve CD4+T cells differentiation through Notch signaling. Lfng regulated Th2 cells differentiation via a Notch-dependent manner and Th1 cells differentiation via a Notch-independent manner. Fringe could be a therapeutic strategy for the management and prevention of allergic asthma. PMID:23071776

Fringe controls naïve CD4(+)T cells differentiation through modulating notch signaling in asthmatic rat models.

Science.gov (United States)

Gu, Wen; Xu, Weiguo; Ding, Tao; Guo, Xuejun

2012-01-01

The ability of Notch signaling to regulate T helper cell development and differentiation has been widely accepted. Fringe, O-fucose-β1,3-N-acetylglucosaminyltransferases modulate Notch receptor expression and promote the Notch signaling pathway through receptor-ligand binding. In this study, we assayed the expression levels of three Fringe homologs in naive CD4(+)T cells in asthmatic rats. We found that Radical Fringe (Rfng) was highly expressed, whereas both Lunatic Fringe (Lfng) and Manic Fringe (Mfng) were expressed at low levels. Down-regulation of Rfng using siRNA, and overexpression of Lfng or Mfng enhanced Th1 subset lineages and diminished Th2 subset lineages. Notch signaling was more activated in asthmatic naïve CD4(+)T cells than in control cells, and Lfng, but not Mfng or Rfng, partly inhibited Notch signaling in asthmatic naïve CD4(+)T lymphocytes. Lfng overexpression resulted in significantly decreased Th2 cytokine production in asthma, which was the same effect as the GSI (γ-secretase inhibitor) treatment alone, but had an increased effect on Th1 cytokines than GSI treatment. Collectively, these data identify the essential role of Fringe modulating naïve CD4(+)T cells differentiation through Notch signaling. Lfng regulated Th2 cells differentiation via a Notch-dependent manner and Th1 cells differentiation via a Notch-independent manner. Fringe could be a therapeutic strategy for the management and prevention of allergic asthma.

26 CFR 1.132-5 - Working condition fringes.

Science.gov (United States)

2010-04-01

... exist unless the employee's employer establishes to the satisfaction of the Commissioner that an overall... example, threats are made on the life of an employee), the bona fide business-oriented security concern is... condition fringe. A “working condition fringe” is any property or service provided to an employee of an...

Interference fringes in synchrotron section topography of implanted silicon with a very large ion range

International Nuclear Information System (INIS)

Wieteska, K.; Dluzewska, K.; Wierzchowski, W.; Graeff, W.

1997-01-01

Silicon crystals implanted with 9 MeV protons to the dose of 5x10 17 cm -2 were studied with X-ray topographic methods using both conventional and synchrotron radiation sources. After the implantation the crystals were thermally and electron annealed. The implantation produced large 600 μm thick shot-through layer while the total thickness of the samples was 1.6 mm. It was confirmed by means of double crystal topography that the whole crystal was elastically bent. The transmission section patterns revealed both parts of the implanted crystal separated by strong contrasts coming from the most damaged layer and distinct interference fringes which appeared on one side of the topograph only. The locations of the fringes changed when the beam entered the other side of the sample. The mechanism of fringe formation was studied with numerical integration of the Takagi-Taupin equations, especially studying the intensity distribution in the diffraction plane. The simulations reproduced the location of the fringes in different geometries and indicate that they can be caused both by variable crystal curvature and variable ion dose. (author)

A far-infrared Michelson interferometer for tokamak electron density measurements using computer-generated reference fringes

International Nuclear Information System (INIS)

Krug, P.A.; Stimson, P.A.; Falconer, I.S.

1986-01-01

A simple far-infrared interferometer which uses the 394 μm laser line from optically-pumped formic acid vapour to measure tokamak electron density is described. This interferometer is unusual in requiring only one detector and a single probing beam since reference fringes during the plasma shot are obtained by computer interpolation between the fringes observed immediately before and after the shot. Electron density has been measured with a phase resolution corresponding to + - 1/20 wavelength fringe shift, which is equivalent to a central density resolution of + - 0.1 x 10 19 m -3 for an assumed parabolic density distribution in a plasma of diameter of 0.2 m, and with a time resolution of 0.2 ms. (author)

On-Chip Method to Measure Mechanical Characteristics of a Single Cell by Using Moiré Fringe

Directory of Open Access Journals (Sweden)

Hirotaka Sugiura

2015-06-01

Full Text Available We propose a method to characterize the mechanical properties of cells using a robot-integrated microfluidic chip (robochip and microscopy. The microfluidic chip is designed to apply the specified deformations to a single detached cell using an on-chip actuator probe. The reaction force is simultaneously measured using an on-chip force sensor composed of a hollow folded beam and probe structure. In order to measure the cellular characteristics in further detail, a sub-pixel level of resolution of probe position is required. Therefore, we utilize the phase detection of moiré fringe. Using this method, the experimental resolution of the probe position reaches 42 nm. This is approximately ten times smaller than the optical wavelength, which is the limit of sharp imaging with a microscope. Calibration of the force sensor is also important in accurately measuring cellular reaction forces. We calibrated the spring constant from the frequency response, by the proposed sensing method of the probe position. As a representative of mechanical characteristics, we measured the elastic modulus of Madin-Darby Cannie Kidney (MDCK cells. In spite of the rigid spring constant, the resolution and sensitivity were twice that achieved in our previous study. Unique cellular characteristics can be elucidated by the improvements in sensing resolution and accuracy.

Enhanced precision of ankle torque measure with an open-unit dynamometer mounted with a 3D force-torque sensor.

Science.gov (United States)

Toumi, A; Leteneur, S; Gillet, C; Debril, J-F; Decoufour, N; Barbier, F; Jakobi, J M; Simoneau-Buessinger, Emilie

2015-11-01

Many studies have focused on maximum torque exerted by ankle joint muscles during plantar flexion. While strength parameters are typically measured with isokinetic or isolated ankle dynamometers, these devices often present substantial limitations for the measurement of torque because they account for force in only 1 dimension (1D), and the device often constrains the body in a position that augments torque through counter movements. The purposes of this study were to determine the contribution of body position to ankle plantar-flexion torque and to assess the use of 1D and 3D torque sensors. A custom designed 'Booted, Open-Unit, Three dimension, Transportable, Ergometer' (B.O.T.T.E.) was used to quantify plantar flexion in two conditions: (1) when the participant was restrained within the unit (locked-unit) and (2) when the participant's position was independent of the ankle dynamometer (open-unit). Ten young males performed maximal voluntary isometric plantar-flexion contractions using the B.O.T.T.E. in open and locked-unit mechanical configurations. The B.O.T.T.E. was reliable with ICC higher than 0.90, and CV lower than 7 %. The plantar-flexion maximal resultant torque was significantly higher in the locked-unit compared with open-unit configuration (P torque sensor significantly underestimated the proper capacity of plantar-flexion torque production (P torque should be performed with an open-unit dynamometer mounted with a 3D sensor that is exclusive of accessory muscles but inclusive of all ankle joint movements.

26 CFR 1.132-6 - De minimis fringes.

Science.gov (United States)

2010-04-01

...) so small as to make accounting for it unreasonable or administratively impracticable. (b) Frequency... of hours worked (e.g., $1.00 per hour for each hour over eight hours) be considered a de minimis... as a working condition fringe if the employee would not have had such special security design but for...

Iterated unscented Kalman filter for phase unwrapping of interferometric fringes.

Science.gov (United States)

Xie, Xianming

2016-08-22

A fresh phase unwrapping algorithm based on iterated unscented Kalman filter is proposed to estimate unambiguous unwrapped phase of interferometric fringes. This method is the result of combining an iterated unscented Kalman filter with a robust phase gradient estimator based on amended matrix pencil model, and an efficient quality-guided strategy based on heap sort. The iterated unscented Kalman filter that is one of the most robust methods under the Bayesian theorem frame in non-linear signal processing so far, is applied to perform simultaneously noise suppression and phase unwrapping of interferometric fringes for the first time, which can simplify the complexity and the difficulty of pre-filtering procedure followed by phase unwrapping procedure, and even can remove the pre-filtering procedure. The robust phase gradient estimator is used to efficiently and accurately obtain phase gradient information from interferometric fringes, which is needed for the iterated unscented Kalman filtering phase unwrapping model. The efficient quality-guided strategy is able to ensure that the proposed method fast unwraps wrapped pixels along the path from the high-quality area to the low-quality area of wrapped phase images, which can greatly improve the efficiency of phase unwrapping. Results obtained from synthetic data and real data show that the proposed method can obtain better solutions with an acceptable time consumption, with respect to some of the most used algorithms.

Measurement of gradient index profiles by Babinet fringe analysis.

Science.gov (United States)

Pandya, T P; Saxena, A K

1979-03-01

A theory for determining one-dimensional ray deflections with the help of distorted Babinet fringes has been developed. An approach for investigating two-dimensional ray deflections has been presented. Applications of the techniques for the study of gradient index glass have been described.

Polarization modeling and predictions for DKIST part 3: focal ratio and thermal dependencies of spectral polarization fringes and optic retardance

Science.gov (United States)

Harrington, David M.; Sueoka, Stacey R.

2018-01-01

Data products from high spectral resolution astronomical polarimeters are often limited by fringes. Fringes can skew derived magnetic field properties from spectropolarimetric data. Fringe removal algorithms can also corrupt the data if the fringes and object signals are too similar. For some narrow-band imaging polarimeters, fringes change the calibration retarder properties and dominate the calibration errors. Systems-level engineering tools for polarimetric instrumentation require accurate predictions of fringe amplitudes, periods for transmission, diattenuation, and retardance. The relevant instabilities caused by environmental, thermal, and optical properties can be modeled and mitigation tools developed. We create spectral polarization fringe amplitude and temporal instability predictions by applying the Berreman calculus and simple interferometric calculations to optics in beams of varying F/ number. We then apply the formalism to superachromatic six-crystal retarders in converging beams under beam thermal loading in outdoor environmental conditions for two of the world's largest observatories: the 10-m Keck telescope and the Daniel K. Inouye Solar Telescope (DKIST). DKIST will produce a 300-W optical beam, which has imposed stringent requirements on the large diameter six-crystal retarders, dichroic beamsplitters, and internal optics. DKIST retarders are used in a converging beam with F/ ratios between 8 and 62. The fringe spectral periods, amplitudes, and thermal models of retarder behavior assisted DKIST optical designs and calibration plans with future application to many astronomical spectropolarimeters. The Low Resolution Imaging Spectrograph with polarimetry instrument at Keck also uses six-crystal retarders in a converging F / 13 beam in a Cassegrain focus exposed to summit environmental conditions providing observational verification of our predictions.

Identifikasi Ketersediaan dan Kualitas Sarana Prasarana Lingkungan di Urban Fringe Area Kelurahan Pudakpayung

Directory of Open Access Journals (Sweden)

Ajeng Dwi Handayani

2014-12-01

Full Text Available Pudakpayung Sub District is the southest in Banyumanik District of Semarang City. This area is a Urban Fringe Area with high population growth and development area for human settlement. But not supported by good facilities and infrastructure. This research is aiming to see the availability and quality of facilities and infrastructure in this urban fringe area. So, this research can give the recommendation about availability and quality of facilities and infrastructure, especially in urban fringe area. This research will identify changes the pattern of human settlement and then identify the availability, quality, and distribution of neighborhoods facilities and infrastructure. The research method used in this research is quantitative descriptive method. The analysis uses the quantitative descriptive analysis with the provisions of SNI 03-1733-2004, scoring with a Likert scale, and spatial mapping. The result of this research indicate changes the pattern of land up and indicate the availability, quality, and distribution of every facilities and infrastructure.

Transport of volatile organic compounds across the capillary fringe

Science.gov (United States)

McCarthy, Kathleen A.; Johnson, Richard L.

1993-01-01

Physical experiments were conducted to investigate the transport of a dissolved volatile organic compound (trichloroethylene, TCE) from shallow groundwater to the unsaturated zone under a variety of conditions including changes in the soil moisture profile and water table position. Experimental data indicated that at moderate groundwater velocities (0.1 m/d), vertical mechanical dispersion was negligible and molecular diffusion was the dominant vertical transport mechanism. Under these conditions, TCE concentrations decreased nearly 3 orders of magnitude across the capillary fringe and soil gas concentrations remained low relative to those of underlying groundwater. Data collected during a water table drop showed a short-term increase in concentrations throughout most of the unsaturated zone, but these concentrations quickly declined and approached initial values after the water table was returned to its original level. In the deep part of the unsaturated zone, the water table drop resulted in a long-term decrease in concentrations, illustrating the effects of hysteresis in the soil moisture profile. A two-dimensional random walk advection-diffusion model was developed to simulate the experimental conditions, and numerical simulations agreed well with experimental data. A simpler, one-dimensional finite-difference diffusion-dispersion model was also developed. One-dimensional simulations based on molecular diffusion also agreed well with experimental data. Simulations which incorporated mechanical dispersion tended to overestimate flux across the capillary fringe. Good agreement between the one- and two-dimensional models suggested that a simple, one-dimensional approximation of vertical transport across the capillary fringe can be useful when conditions are appropriate.

Fringing field effects in negative capacitance field-effect transistors with a ferroelectric gate insulator

Science.gov (United States)

Hattori, Junichi; Fukuda, Koichi; Ikegami, Tsutomu; Ota, Hiroyuki; Migita, Shinji; Asai, Hidehiro; Toriumi, Akira

2018-04-01

We study the effects of fringing electric fields on the behavior of negative-capacitance (NC) field-effect transistors (FETs) with a silicon-on-insulator body and a gate stack consisting of an oxide film, an internal metal film, a ferroelectric film, and a gate electrode using our own device simulator that can properly handle the complicated relationship between the polarization and the electric field in ferroelectric materials. The behaviors of such NC FETs and the corresponding metal-oxide-semiconductor (MOS) FETs are simulated and compared with each other to evaluate the effects of the NC of the ferroelectric film. Then, the fringing field effects are evaluated by comparing the NC effects in NC FETs with and without gate spacers. The fringing field between the gate stack, especially the internal metal film, and the source/drain region induces more charges at the interface of the film with the ferroelectric film. Accordingly, the function of the NC to modulate the gate voltage and the resulting function to improve the subthreshold swing are enhanced. We also investigate the relationships of these fringing field effects to the drain voltage and four design parameters of NC FETs, i.e., gate length, gate spacer permittivity, internal metal film thickness, and oxide film thickness.

Explanations for Long-Distance Counter-Urban Migration into Fringe Areas in Denmark

DEFF Research Database (Denmark)

Andersen, Hans Skifter

2009-01-01

In Denmark, as in most other European countries, there is a net migration from the less urbanized to the more urbanized parts of the country. This article summarizes the results of a Danish study on the extent and composition of migration fl ows; and on factors and conditions that have a decisive...... infl uence on migration to fringe areas. The study shows that a considerable share of movers to the fringe areas in Denmark can be characterised as income-transfer mover. They are people without employment moving to get lower housing costs. But there are also groups of people moving to employment...

FSD-HSO Optimization Algorithm for Closed Fringes Interferogram Demodulation

Directory of Open Access Journals (Sweden)

Ulises H. Rodriguez-Marmolejo

2016-01-01

Full Text Available Due to the physical nature of the interference phenomenon, extracting the phase of an interferogram is a known sinusoidal modulation problem. In order to solve this problem, a new hybrid mathematical optimization model for phase extraction is established. The combination of frequency guide sequential demodulation and harmony search optimization algorithms is used for demodulating closed fringes patterns in order to find the phase of interferogram applications. The proposed algorithm is tested in four sets of different synthetic interferograms, finding a range of average relative error in phase reconstructions of 0.14–0.39 rad. For reference, experimental results are compared with the genetic algorithm optimization technique, obtaining a reduction in the error up to 0.1448 rad. Finally, the proposed algorithm is compared with a very known demodulation algorithm, using a real interferogram, obtaining a relative error of 1.561 rad. Results are shown in patterns with complex fringes distribution.

Controversy among giants: Young's experiment and loss of fringe visibility at low photon-count levels

Science.gov (United States)

Rhodes, William T.

2011-09-01

An ideal beam splitter model for an absorber presented by Leonhardt in his book Measuring the Quantum State of Light (Cambridge University Press, 1997) has intriguing implications for the simple Young's fringe experiment in the photon-counting regime. Specifically, it suggests that different results will be obtained depending on whether the light forming the fringes is attenuated at the source or at the slits.

In situ calibration of an interferometric velocity sensor for measuring small scale flow structures using a Talbot-pattern

Science.gov (United States)

König, Jörg; Czarske, Jürgen

2017-10-01

Small scale flow phenomena play an important role across engineering, biological and chemical sciences. To gain deeper understanding of the influence of those flow phenomena involved, measurement techniques with high spatial resolution are often required, presuming a calibration of very low uncertainty. To enable such measurements, a method for the in situ calibration of an interferometric flow velocity profile sensor is presented. This sensor, with demonstrated spatial resolution better than 1 μm, allows for spatially-resolving measurements with low velocity uncertainty in flows with high velocity gradients, on condition that the spatial behavior of the interference fringe systems is well-known by calibration with low uncertainty, especially challenging to obtain at applications with geometries difficult to access. The calibration method described herein uses three interfering beams to form the interference fringe systems of the sensor, yielding Doppler burst signals exhibiting two peaks in the frequency domain whose amplitude ratio varies periodically along the measurement volume major z-axis, giving a further independent value of the axial tracer particle position that can be used to determine the calibration functions of the sensor during the flow measurement. A flow measurement in a microchannel experimentally validates that the presented approach allows for simultaneously estimating the calibration functions and the velocity profile, providing flow measurements with very low systematic measurement errors of the particle position of less than 400 nm (confidence interval 95%). In that way, the interferometric flow velocity profile sensor utilizing the in situ self-calibration method promises valuable insights on small scale flow phenomena, such as those given in shear and boundary layer flows, by featuring reliable flow measurements due to minimum systematic and statistical measurement errors.

Combination of oriented partial differential equation and shearlet transform for denoising in electronic speckle pattern interferometry fringe patterns.

Science.gov (United States)

Xu, Wenjun; Tang, Chen; Gu, Fan; Cheng, Jiajia

2017-04-01

It is a key step to remove the massive speckle noise in electronic speckle pattern interferometry (ESPI) fringe patterns. In the spatial-domain filtering methods, oriented partial differential equations have been demonstrated to be a powerful tool. In the transform-domain filtering methods, the shearlet transform is a state-of-the-art method. In this paper, we propose a filtering method for ESPI fringe patterns denoising, which is a combination of second-order oriented partial differential equation (SOOPDE) and the shearlet transform, named SOOPDE-Shearlet. Here, the shearlet transform is introduced into the ESPI fringe patterns denoising for the first time. This combination takes advantage of the fact that the spatial-domain filtering method SOOPDE and the transform-domain filtering method shearlet transform benefit from each other. We test the proposed SOOPDE-Shearlet on five experimentally obtained ESPI fringe patterns with poor quality and compare our method with SOOPDE, shearlet transform, windowed Fourier filtering (WFF), and coherence-enhancing diffusion (CEDPDE). Among them, WFF and CEDPDE are the state-of-the-art methods for ESPI fringe patterns denoising in transform domain and spatial domain, respectively. The experimental results have demonstrated the good performance of the proposed SOOPDE-Shearlet.

Fringe Benefits Provision by Rural Small Businesses

OpenAIRE

Jayachandran N. Variyam; David S. Kraybill

1998-01-01

We examine the relationship between employer size and the provision of fringe benefits in a large sample of rural businesses. A clear employer size-benefits relationship exists only in the case of health insurance, while other benefits are not strongly linked to employer size. The negative relationship between employer size and health insurance is weaker, though still existent, in businesses whose employees have relatively high skill levels. Single, independent establishments and sole proprie...

Micro Extrinsic Fiber-Optic Fabry-Perot Interferometric Sensor Based on Erbium- and Boron-Doped Fibers

International Nuclear Information System (INIS)

Yun-Jiang, Rao; Bing, Xu; Zeng-Ling, Ran; Yuan, Gong

2010-01-01

Micro extrinsic Fabry–Perot interferometers (MEFPIs), with cavity lengths of up to ∼ 9 μm and maximum fringe contrast of ∼ 19 dB, are fabricated by chemically etching Er- and B-doped optical fibers and then splicing the etched fiber to a single-mode fiber, for the first time to the best of our knowledge. The strain and temperature responses of the MEFPI sensors are investigated experimentally. Good linearity and high sensitivity are achieved. Such a type of MEFPI sensor is cost-effective and suitable for mass production, indicating its great potential for a wide range of applications. (fundamental areas of phenomenology(including applications))

Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms.

Science.gov (United States)

Volkov, V V; Han, M G; Zhu, Y

2013-11-01

We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice. Published by Elsevier B.V.

Real-time detection and elimination of nonorthogonality error in interference fringe processing

International Nuclear Information System (INIS)

Hu Haijiang; Zhang Fengdeng

2011-01-01

In the measurement system of interference fringe, the nonorthogonality error is a main error source that influences the precision and accuracy of the measurement system. The detection and elimination of the error has been an important target. A novel method that only uses the cross-zero detection and the counting is proposed to detect and eliminate the nonorthogonality error in real time. This method can be simply realized by means of the digital logic device, because it does not invoke trigonometric functions and inverse trigonometric functions. And it can be widely used in the bidirectional subdivision systems of a Moire fringe and other optical instruments.

Anacostia River fringe wetlands restoration project: final report for the five-year monitoring program (2003 through 2007)

Science.gov (United States)

Krafft, Cairn C.; Hammerschlag, Richard S.; Guntenspergen, Glenn R.

2009-01-01

The 6-hectare (ha) freshwater tidal Anacostia River Fringe Wetlands (Fringe Wetlands) were reconstructed along the mainstem of the Anacostia River in Washington, DC (Photograph 1, Figure 1) during the summer of 2003. The Fringe Wetlands consist of two separate planting cells. Fringe A, located adjacent to Lower Kingman Island, on the west bank of the Anacostia River, occupies 1.6 ha; Fringe B, located on the east bank of the Anacostia River, occupies 4.4 ha. This project is the third in a series of freshwater tidal wetland reconstructions on the Anacostia River designed and implemented by the US Army Corps of Engineers (USACE) Baltimore District and District Department of the Environment (DDOE) on lands managed by the National Park Service (NPS). The first was Kenilworth Marsh, reconstructed in 1993 (Syphax and Hammerschlag 2005); the second was Kingman Marsh, reconstructed in 2000 (Hammerschlag et al. 2006). Kenilworth and Kingman were both constructed in low-energy backwaters of the Anacostia. However, the Fringe Wetlands, which were constructed on two pre-existing benches along the high-energy mainstem, required sheet piling to provide protection from erosive impacts of increased flow and volume of water associated with storm events during the establishment phase (Photograph 2). All three projects required the placement of dredged sediment materials to increase elevations enough to support emergent vegetation (Photograph 3). The purpose of all three wetland reconstruction projects was to restore pieces of the once extensive tidal freshwater marsh habitat that bordered the Anacostia River historically, prior to the dredge and fill operations and sea wall installation that took place there in the early to mid-1900's (Photograph 4).

Spatial dual-orthogonal (SDO) phase-shifting algorithm by pre-recomposing the interference fringe.

Science.gov (United States)

Wang, Yi; Li, Bingbo; Zhong, Liyun; Tian, Jindong; Lu, Xiaoxu

2017-07-24

In the case that the phase distribution of interferogram is nonuniform and the background/modulation amplitude change rapidly, the current self-calibration algorithms with better performance like principal components analysis (PCA) and advanced iterative algorithm (AIA) cannot work well. In this study, from three or more phase-shifting interferograms with unknown phase-shifts, we propose a spatial dual-orthogonal (SDO) phase-shifting algorithm with high accuracy through using the spatial orthogonal property of interference fringe, in which a new sequence of fringe patterns with uniform phase distribution can be constructed by pre-recomposing original interferograms to determine their corresponding optimum combination coefficients, which are directly related with the phase shifts. Both simulation and experimental results show that using the proposed SDO algorithm, we can achieve accurate phase from the phase-shifting interferograms with nonuniform phase distribution, non-constant background and arbitrary phase shifts. Specially, it is found that the accuracy of phase retrieval with the proposed SDO algorithm is insensitive to the variation of fringe pattern, and this will supply a guarantee for high accuracy phase measurement and application.

Optical coherent control in semiconductors: Fringe contrast and inhomogeneous broadening

DEFF Research Database (Denmark)

Østergaard, John Erland; Vadim, Lyssenko; Hvam, Jørn Märcher

2001-01-01

in the interplay between the homogeneous and inhomogeneous broadenings are measured. Based on these experiments, a coherent control model describing the optical fringe contrast using different detection schemes, such as photoluminescence or four-wave mixing, is established. Significant spectral modulation...

On-line process analysis innovation: DiComp (tm) shunting dielectric sensor technology

Science.gov (United States)

Davis, Craig R.; Waldman, Frank A.

1993-01-01

The DiComp Shunting Dielectric Sensor (SDS) is a new patent-pending technology developed under the Small Business Innovation Research Program (SBIR) for NASA's Kennedy Space Center. The incorporation of a shunt electrode into a conventional fringing field dielectric sensor makes the SDS uniquely sensitive to changes in material dielectric properties in the KHz to MHz range which were previously detectable only at GHz measurement frequencies. The initial NASA application of the SDS for Nutrient Delivery Control has demonstrated SDS capabilities for thickness and concentration measurement of Hoagland nutrient solutions. The commercial introduction of DiComp SDS technology for concentration and percent solids measurements in dispersions, emulsions and solutions represents a new technology for process measurements for liquids in a variety of industries.

Two-dimensional wavelet transform for reliability-guided phase unwrapping in optical fringe pattern analysis.

Science.gov (United States)

Li, Sikun; Wang, Xiangzhao; Su, Xianyu; Tang, Feng

2012-04-20

This paper theoretically discusses modulus of two-dimensional (2D) wavelet transform (WT) coefficients, calculated by using two frequently used 2D daughter wavelet definitions, in an optical fringe pattern analysis. The discussion shows that neither is good enough to represent the reliability of the phase data. The differences between the two frequently used 2D daughter wavelet definitions in the performance of 2D WT also are discussed. We propose a new 2D daughter wavelet definition for reliability-guided phase unwrapping of optical fringe pattern. The modulus of the advanced 2D WT coefficients, obtained by using a daughter wavelet under this new daughter wavelet definition, includes not only modulation information but also local frequency information of the deformed fringe pattern. Therefore, it can be treated as a good parameter that represents the reliability of the retrieved phase data. Computer simulation and experimentation show the validity of the proposed method.

Phase extraction based on iterative algorithm using five-frame crossed fringes in phase measuring deflectometry

Science.gov (United States)

Jin, Chengying; Li, Dahai; Kewei, E.; Li, Mengyang; Chen, Pengyu; Wang, Ruiyang; Xiong, Zhao

2018-06-01

In phase measuring deflectometry, two orthogonal sinusoidal fringe patterns are separately projected on the test surface and the distorted fringes reflected by the surface are recorded, each with a sequential phase shift. Then the two components of the local surface gradients are obtained by triangulation. It usually involves some complicated and time-consuming procedures (fringe projection in the orthogonal directions). In addition, the digital light devices (e.g. LCD screen and CCD camera) are not error free. There are quantization errors for each pixel of both LCD and CCD. Therefore, to avoid the complex process and improve the reliability of the phase distribution, a phase extraction algorithm with five-frame crossed fringes is presented in this paper. It is based on a least-squares iterative process. Using the proposed algorithm, phase distributions and phase shift amounts in two orthogonal directions can be simultaneously and successfully determined through an iterative procedure. Both a numerical simulation and a preliminary experiment are conducted to verify the validity and performance of this algorithm. Experimental results obtained by our method are shown, and comparisons between our experimental results and those obtained by the traditional 16-step phase-shifting algorithm and between our experimental results and those measured by the Fizeau interferometer are made.

Diffusive-dispersive mass transfer in the capillary fringe: Impact of water table fluctuations and heterogeneities

DEFF Research Database (Denmark)

Grathwohl, Peter; Haberer, Cristina; Ye, Yu

Diffusive–dispersive mass transfer in the capillary fringe is important for many groundwater quality issues such as transfer of volatile compounds into (and out of) the groundwater, the supply of oxygen for aerobic degradation of hydrocarbons as well as for precipitation of minerals (e.g. iron...... hydroxides). 2D-laboratory scale experiments were used to investigate the transfer of oxygen into groundwater under non-reactive and reactive conditions, at steady state and with water table fluctuations. Results show that transfer of oxygen is limited by transverse dispersion in the capillary fringe...... and the dispersion coefficients are the same as below the water table. Water table fluctuations cause temporarily increased fluxes of oxygen into groundwater during draining conditions and entrapped air after water table rise. High-permeability inclusions in the capillary fringe enhance mass transfer of oxygen...

Advanced Dispersed Fringe Sensing Algorithm for Coarse Phasing Segmented Mirror Telescopes

Science.gov (United States)

Spechler, Joshua A.; Hoppe, Daniel J.; Sigrist, Norbert; Shi, Fang; Seo, Byoung-Joon; Bikkannavar, Siddarayappa A.

2013-01-01

Segment mirror phasing, a critical step of segment mirror alignment, requires the ability to sense and correct the relative pistons between segments from up to a few hundred microns to a fraction of wavelength in order to bring the mirror system to its full diffraction capability. When sampling the aperture of a telescope, using auto-collimating flats (ACFs) is more economical. The performance of a telescope with a segmented primary mirror strongly depends on how well those primary mirror segments can be phased. One such process to phase primary mirror segments in the axial piston direction is dispersed fringe sensing (DFS). DFS technology can be used to co-phase the ACFs. DFS is essentially a signal fitting and processing operation. It is an elegant method of coarse phasing segmented mirrors. DFS performance accuracy is dependent upon careful calibration of the system as well as other factors such as internal optical alignment, system wavefront errors, and detector quality. Novel improvements to the algorithm have led to substantial enhancements in DFS performance. The Advanced Dispersed Fringe Sensing (ADFS) Algorithm is designed to reduce the sensitivity to calibration errors by determining the optimal fringe extraction line. Applying an angular extraction line dithering procedure and combining this dithering process with an error function while minimizing the phase term of the fitted signal, defines in essence the ADFS algorithm.

Analysis of Professional Fringe Benefits, 1978-79. OMNI Report.

Science.gov (United States)

Vater, James J.; Riddle, Richard A.

This report contains data collected from 275 Pennsylvania school districts for the 1978-79 school year. The data reflect policies and practices affecting fringe benefits for professional employees. The report is divided into three major sections. The first section presents comparative data for 30 variables on a statewide, size, and wealth basis.…

Analysis of Professional Fringe Benefits 1977-78. OMNI Report.

Science.gov (United States)

Caldwell, William E.; Vater, James J.

This report contains data collected from 275 Pennsylvania school districts for the 1977-78 school year. The data reflect policies and practices affecting fringe benefits for professional employees. The report is divided into three major sections. The first section presents comparative data for 30 variables on a statewide, size, and wealth basis.…

Demodulation of moire fringes in digital holographic interferometry using an extended Kalman filter.

Science.gov (United States)

Ramaiah, Jagadesh; Rastogi, Pramod; Rajshekhar, Gannavarpu

2018-03-10

This paper presents a method for extracting multiple phases from a single moire fringe pattern in digital holographic interferometry. The method relies on component separation using singular value decomposition and an extended Kalman filter for demodulating the moire fringes. The Kalman filter is applied by modeling the interference field locally as a multi-component polynomial phase signal and extracting the associated multiple polynomial coefficients using the state space approach. In addition to phase, the corresponding multiple phase derivatives can be simultaneously extracted using the proposed method. The applicability of the proposed method is demonstrated using simulation and experimental results.

Lunatic, Manic and Radical Fringe Each Promote T and B Cell Development

Science.gov (United States)

Song, Yinghui; Kumar, Vivek; Wei, Hua-Xing; Qiu, Ju; Stanley, Pamela

2015-01-01

Lunatic, Manic and Radical Fringe (LFNG, MFNG and RFNG) are N-acetylglucosaminyltransferases that modify Notch receptors and regulate Notch signaling. Loss of LFNG affects thymic T cell development and LFNG and MFNG are required for marginal zone (MZ) B cell development. However, roles for MFNG and RFNG in T cell development, RFNG in B cell development, or Fringes in T and B cell activation, are not identified. Here we show that Lfng/Mfng/Rfng triple knockout (Fng tKO) mice exhibited reduced binding of DLL4 Notch ligand to CD4/CD8 double-negative (DN) T cell progenitors, and reduced expression of NOTCH1 targets Deltex1 and CD25. Fng tKO mice had reduced frequencies of DN1/cKit+ and DN2 T cell progenitors and CD4+CD8+ double positive (DP) T cell precursors, but increased frequencies of CD4+ and CD8+ single positive (SP) T cells in thymus. In spleen, Fng tKO mice had reduced frequencies of CD4+, CD8+, central memory T cells and marginal zone (MZ) B cells, and an increased frequency of effector memory T cells, neutrophils, follicular (Fo) and MZ P B cells. The Fng tKO phenotype was cell-autonomous and largely rescued in mice expressing one allele of a single Fng gene. Stimulation of Fng tKO splenocytes with anti-CD3/CD28 beads or lipopolysaccharide gave reduced proliferation compared to controls, and the generation of activated T cells by concanavalin A or L-PHA was also reduced in Fng tKO mice. Therefore, each Fringe contributes to T and B cell development, and Fringe is required for optimal in vitro stimulation of T and B cells. PMID:26608918

The apical actin fringe contributes to localized cell wall deposition and polarized growth in the lily pollen tube.

Science.gov (United States)

Rounds, Caleb M; Hepler, Peter K; Winship, Lawrence J

2014-09-01

In lily (Lilium formosanum) pollen tubes, pectin, a major component of the cell wall, is delivered through regulated exocytosis. The targeted transport and secretion of the pectin-containing vesicles may be controlled by the cortical actin fringe at the pollen tube apex. Here, we address the role of the actin fringe using three different inhibitors of growth: brefeldin A, latrunculin B, and potassium cyanide. Brefeldin A blocks membrane trafficking and inhibits exocytosis in pollen tubes; it also leads to the degradation of the actin fringe and the formation of an aggregate of filamentous actin at the base of the clear zone. Latrunculin B, which depolymerizes filamentous actin, markedly slows growth but allows focused pectin deposition to continue. Of note, the locus of deposition shifts frequently and correlates with changes in the direction of growth. Finally, potassium cyanide, an electron transport chain inhibitor, briefly stops growth while causing the actin fringe to completely disappear. Pectin deposition continues but lacks focus, instead being delivered in a wide arc across the pollen tube tip. These data support a model in which the actin fringe contributes to the focused secretion of pectin to the apical cell wall and, thus, to the polarized growth of the pollen tube. © 2014 American Society of Plant Biologists. All Rights Reserved.

At-wavelength metrology using the moiré fringe analysis method based on a two dimensional grating interferometer

International Nuclear Information System (INIS)

Wang, Hongchang; Berujon, Sebastien; Pape, Ian; Rutishauser, Simon; David, Christian; Sawhney, Kawal

2013-01-01

A two-dimensional (2D) grating interferometer was used to perform at-wavelength metrology. A Fast Fourier Transform (FFT) of the interferograms recovers the differential X-ray beam phase in two orthogonal directions simultaneously. As an example, the X-ray wavefronts downstream from a Fresnel Zone plate were measured using the moiré fringe analysis method, which requires only a single image. The rotating shearing interferometer technique for moiré fringe analysis was extended from one dimension to two dimensions to carry out absolute wavefront metrology. In addition, the 2D moiré fringes were extrapolated using Gerchberg's method to reduce the boundary artifacts. The advantages and limitations of the phase-stepping method and the moiré fringe analysis method are also discussed. -- Highlights: ► A rapid and sensitive strip test for CPPU (forchlorfenuron) detection is reported. ► Carbon nanoparticles were used for antibody labelling. ► A common flatbed scanner was employed to the quantitate strip spots. ► The new method was successfully applied to the analysis of the field samples

EFFECT OF DIGITAL FRINGE PROJECTION PARAMETERS ON 3D RECONSTRUCTION ACCURACY

Directory of Open Access Journals (Sweden)

A. Babaei

2013-09-01

This paper aims to evaluate different parameters which affect the accuracy of the final results. For this purpose, some test were designed and implemented. These tests assess the number of phase shifts, spatial frequency of the fringe pattern, light condition, noise level of images, and the color and material of target objects on the quality of resulted phase map. The evaluation results demonstrate that digital fringe projection method is capable of obtaining depth map of complicated object with high accuracy. The contrast test results showed that this method is able to work under different ambient light condition; although at places with high light condition will not work properly. The results of implementation on different objects with various materials, color and shapes demonstrate the high capability of this method of 3D reconstruction.

49 CFR 1242.29 - Fringe benefits (accounts 12-17-00, 12-18-00, and 12-19-00).

Science.gov (United States)

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Fringe benefits (accounts 12-17-00, 12-18-00, and... RAILROADS 1 Operating Expenses-Way and Structures § 1242.29 Fringe benefits (accounts 12-17-00, 12-18-00, and 12-19-00). Separate common expenses in the running subactivity in the same proportion as the...

Streak camera recording of interferometer fringes

International Nuclear Information System (INIS)

Parker, N.L.; Chau, H.H.

1977-01-01

The use of an electronic high-speed camera in the streaking mode to record interference fringe motion from a velocity interferometer is discussed. Advantages of this method over the photomultiplier tube-oscilloscope approach are delineated. Performance testing and data for the electronic streak camera are discussed. The velocity profile of a mylar flyer accelerated by an electrically exploded bridge, and the jump-off velocity of metal targets struck by these mylar flyers are measured in the camera tests. Advantages of the streak camera include portability, low cost, ease of operation and maintenance, simplified interferometer optics, and rapid data analysis

Phase retrieval from the phase-shift moiré fringe patterns in simultaneous dual-wavelength interferometry

Science.gov (United States)

Cheng, Jinlong; Gao, Zhishan; Bie, Shuyou; Dou, Yimeng; Ni, Ruihu; Yuan, Qun

2018-02-01

Simultaneous dual-wavelength interferometry (SDWI) could extend the measured range of each single-wavelength interferometry. The moiré fringe generated in SDWI indirectly represents the information of the measured long synthetic-wavelength ({λ }{{S}}) phase, thus the phase demodulation is rather arduous. To address this issue, we present a method to convert the moiré fringe pattern into a synthetic-wavelength interferogram (moiré to synthetic-wavelength, MTS). After the square of the moiré fringe pattern in the MTS method, the additive moiré pattern is turned into a multiplicative one. And the synthetic-wavelength interferogram could be obtained by a low-pass filtering in spectrum of the multiplicative moiré fringe pattern. Therefore, when the dual-wavelength interferometer is implemented with the π/2 phase shift at {λ }{{S}}, a sequence of synthetic-wavelength phase-shift interferograms with π/2 phase shift could be obtained after the MTS method processing on the captured moiré fringe patterns. And then the synthetic-wavelength phase could be retrieved by the conventional phase-shift algorithm. Compared with other methods in SDWI, the proposed MTS approach could reduce the restriction of the phase shift and frame numbers for the adoption of the conventional phase-shift algorithm. Following, numerical simulations are executed to evaluate the performance of the MTS method in processing time, frames of interferograms and the phase shift error compensation. And the necessary linear carrier for MTS method is less than 0.11 times of the traditional dual-wavelength spatial-domain Fourier transform method. Finally, the deviations for MTS method in experiment are 0.97% for a step with the height of 7.8 μm and 1.11% for a Fresnel lens with the step height of 6.2328 μm.

Real-Time and High-Resolution 3D Face Measurement via a Smart Active Optical Sensor.

Science.gov (United States)

You, Yong; Shen, Yang; Zhang, Guocai; Xing, Xiuwen

2017-03-31

The 3D measuring range and accuracy in traditional active optical sensing, such as Fourier transform profilometry, are influenced by the zero frequency of the captured patterns. The phase-shifting technique is commonly applied to remove the zero component. However, this phase-shifting method must capture several fringe patterns with phase difference, thereby influencing the real-time performance. This study introduces a smart active optical sensor, in which a composite pattern is utilized. The composite pattern efficiently combines several phase-shifting fringes and carrier frequencies. The method can remove zero frequency by using only one pattern. Model face reconstruction and human face measurement were employed to study the validity and feasibility of this method. Results show no distinct decrease in the precision of the novel method unlike the traditional phase-shifting method. The texture mapping technique was utilized to reconstruct a nature-appearance 3D digital face.

The Radio Frequency Health Node Wireless Sensor System

Science.gov (United States)

Valencia, J. Emilio; Stanley, Priscilla C.; Mackey, Paul J.

2009-01-01

The Radio Frequency Health Node (RFHN) wireless sensor system differs from other wireless sensor systems in ways originally intended to enhance utility as an instrumentation system for a spacecraft. The RFHN can also be adapted to use in terrestrial applications in which there are requirements for operational flexibility and integrability into higher-level instrumentation and data acquisition systems. As shown in the figure, the heart of the system is the RFHN, which is a unit that passes commands and data between (1) one or more commercially available wireless sensor units (optionally, also including wired sensor units) and (2) command and data interfaces with a local control computer that may be part of the spacecraft or other engineering system in which the wireless sensor system is installed. In turn, the local control computer can be in radio or wire communication with a remote control computer that may be part of a higher-level system. The remote control computer, acting via the local control computer and the RFHN, cannot only monitor readout data from the sensor units but can also remotely configure (program or reprogram) the RFHN and the sensor units during operation. In a spacecraft application, the RFHN and the sensor units can also be configured more nearly directly, prior to launch, via a serial interface that includes an umbilical cable between the spacecraft and ground support equipment. In either case, the RFHN wireless sensor system has the flexibility to be configured, as required, with different numbers and types of sensors for different applications. The RFHN can be used to effect realtime transfer of data from, and commands to, the wireless sensor units. It can also store data for later retrieval by an external computer. The RFHN communicates with the wireless sensor units via a radio transceiver module. The modular design of the RFHN makes it possible to add radio transceiver modules as needed to accommodate additional sets of wireless sensor

Polarization modeling and predictions for DKIST part 2: application of the Berreman calculus to spectral polarization fringes of beamsplitters and crystal retarders

Science.gov (United States)

Harrington, David M.; Snik, Frans; Keller, Christoph U.; Sueoka, Stacey R.; van Harten, Gerard

2017-10-01

We outline polarization fringe predictions derived from an application of the Berreman calculus for the Daniel K. Inouye Solar Telescope (DKIST) retarder optics. The DKIST retarder baseline design used six crystals, single-layer antireflection coatings, thick cover windows, and oil between all optical interfaces. This tool estimates polarization fringes and optic Mueller matrices as functions of all optical design choices. The amplitude and period of polarized fringes under design changes, manufacturing errors, tolerances, and several physical factors can now be estimated. This tool compares well with observations of fringes for data collected with the spectropolarimeter for infrared and optical regions at the Dunn Solar Telescope using bicrystalline achromatic retarders as well as laboratory tests. With this tool, we show impacts of design decisions on polarization fringes as impacted by antireflection coatings, oil refractive indices, cover window presence, and part thicknesses. This tool helped DKIST decide to remove retarder cover windows and also recommends reconsideration of coating strategies for DKIST. We anticipate this tool to be essential in designing future retarders for mitigation of polarization and intensity fringe errors in other high spectral resolution astronomical systems.

Calibration method for projector-camera-based telecentric fringe projection profilometry system.

Science.gov (United States)

Liu, Haibo; Lin, Huijing; Yao, Linshen

2017-12-11

By combining a fringe projection setup with a telecentric lens, a fringe pattern could be projected and imaged within a small area, making it possible to measure the three-dimensional (3D) surfaces of micro-components. This paper focuses on the flexible calibration of the fringe projection profilometry (FPP) system using a telecentric lens. An analytical telecentric projector-camera calibration model is introduced, in which the rig structure parameters remain invariant for all views, and the 3D calibration target can be located on the projector image plane with sub-pixel precision. Based on the presented calibration model, a two-step calibration procedure is proposed. First, the initial parameters, e.g., the projector-camera rig, projector intrinsic matrix, and coordinates of the control points of a 3D calibration target, are estimated using the affine camera factorization calibration method. Second, a bundle adjustment algorithm with various simultaneous views is applied to refine the calibrated parameters, especially the rig structure parameters and coordinates of the control points forth 3D target. Because the control points are determined during the calibration, there is no need for an accurate 3D reference target, whose is costly and extremely difficult to fabricate, particularly for tiny objects used to calibrate the telecentric FPP system. Real experiments were performed to validate the performance of the proposed calibration method. The test results showed that the proposed approach is very accurate and reliable.

A high-resolution non-invasive approach to quantify oxygen transport across the capillary fringe and within the underlying groundwater.

Science.gov (United States)

Haberer, Christina M; Rolle, Massimo; Liu, Sanheng; Cirpka, Olaf A; Grathwohl, Peter

2011-03-25

Oxygen transport across the capillary fringe is relevant for many biogeochemical processes. We present a non-invasive technique, based on optode technology, to measure high-resolution concentration profiles of oxygen across the unsaturated/saturated interface. By conducting a series of quasi two-dimensional flow-through laboratory experiments, we show that vertical hydrodynamic dispersion in the water-saturated part of the capillary fringe is the process limiting the mass transfer of oxygen. A number of experimental conditions were tested in order to investigate the influence of grain size and horizontal flow velocity on transverse vertical dispersion in the capillary fringe. In the same setup, analogous experiments were simultaneously carried out in the fully water-saturated zone, therefore allowing a direct comparison with oxygen transfer across the capillary fringe. The outcomes of the experiments under various conditions show that oxygen transport in the two zones of interest (i.e., the unsaturated/saturated interface and the saturated zone) is characterized by very similar transverse dispersion coefficients. An influence of the capillary fringe morphology on oxygen transport has not been observed. These results may be explained by the narrow grain size distribution used in the experiments, leading to a steep decline in water saturation at the unsaturated/saturated interface and to the absence of trapped gas in this transition zone. We also modeled flow (applying the van Genuchten and the Brooks-Corey relationships) and two-dimensional transport across the capillary fringe, obtaining simulated profiles of equivalent aqueous oxygen concentration that were in good agreement with the observations. Copyright © 2010 Elsevier B.V. All rights reserved.

Evolution and loss of long-fringed petals: a case study using a dated phylogeny of the snake gourds, Trichosanthes (Cucurbitaceae

Directory of Open Access Journals (Sweden)

de Boer Hugo J

2012-07-01

Full Text Available Abstract Background The Cucurbitaceae genus Trichosanthes comprises 90–100 species that occur from India to Japan and southeast to Australia and Fiji. Most species have large white or pale yellow petals with conspicuously fringed margins, the fringes sometimes several cm long. Pollination is usually by hawkmoths. Previous molecular data for a small number of species suggested that a monophyletic Trichosanthes might include the Asian genera Gymnopetalum (four species, lacking long petal fringes and Hodgsonia (two species with petals fringed. Here we test these groups’ relationships using a species sampling of c. 60% and 4759 nucleotides of nuclear and plastid DNA. To infer the time and direction of the geographic expansion of the Trichosanthes clade we employ molecular clock dating and statistical biogeographic reconstruction, and we also address the gain or loss of petal fringes. Results Trichosanthes is monophyletic as long as it includes Gymnopetalum, which itself is polyphyletic. The closest relative of Trichosanthes appears to be the sponge gourds, Luffa, while Hodgsonia is more distantly related. Of six morphology-based sections in Trichosanthes with more than one species, three are supported by the molecular results; two new sections appear warranted. Molecular dating and biogeographic analyses suggest an Oligocene origin of Trichosanthes in Eurasia or East Asia, followed by diversification and spread throughout the Malesian biogeographic region and into the Australian continent. Conclusions Long-fringed corollas evolved independently in Hodgsonia and Trichosanthes, followed by two losses in the latter coincident with shifts to other pollinators but not with long-distance dispersal events. Together with the Caribbean Linnaeosicyos, the Madagascan Ampelosicyos and the tropical African Telfairia, these cucurbit lineages represent an ideal system for more detailed studies of the evolution and function of petal fringes in plant

48 CFR 22.406-2 - Wages, fringe benefits, and overtime.

Science.gov (United States)

2010-10-01

... exact cash amounts. In these cases, the hourly cash equivalent of the cost of these items shall be... the contractor's contributions, costs, or payment of cash equivalents for fringe benefits. Overtime... cash to the laborer or mechanic, or deducted from payments under the conditions set forth in 29 CFR 3.5...

3D shape measurement of automotive glass by using a fringe reflection technique

Science.gov (United States)

Skydan, O. A.; Lalor, M. J.; Burton, D. R.

2007-01-01

In automotive and glass making industries, there is a need for accurately measuring the 3D shapes of reflective surfaces to speed up and ensure product development and manufacturing quality by using non-contact techniques. This paper describes a technique for the measurement of non-full-field reflective surfaces of automotive glass by using a fringe reflection technique. Physical properties of the measurement surfaces do not allow us to apply optical geometries used in existing techniques for surface measurement based upon direct fringe pattern illumination. However, this property of surface reflectivity can be used to implement similar ideas from existing techniques in a new improved method. In other words, the reflective surface can be used as a mirror to reflect illuminated fringe patterns onto a screen behind. It has been found that in the case of implementing the reflective fringe technique, the phase-shift distribution depends not only on the height of the object but also on the slope at each measurement point. This requires the solving of differential equations to find the surface slope and height distributions in the x and y directions and development of the additional height reconstruction algorithms. The main focus has been made on developing a mathematical model of the optical sub-system and discussing ways for its practical implementation including calibration procedures. A number of implemented image processing algorithms for system calibration and data analysis are discussed and two experimental results are given for automotive glass surfaces with different shapes and defects. The proposed technique showed the ability to provide accurate non-destructive measurement of 3D shapes of the reflective automotive glass surfaces and can be used as a key element for a glass shape quality control system on-line or in a laboratory environment.

Record number (11 000) of interference fringes obtained by a 1 MV field-emission electron microscope

International Nuclear Information System (INIS)

Akashi, Tetsuya; Harada, Ken; Matsuda, Tsuyoshi; Kasai, Hiroto; Tonomura, Akira; Furutsu, Tadao; Moriya, Noboru; Yoshida, Takaho; Kawasaki, Takeshi; Kitazawa, Koichi; Koinuma, Hideomi

2002-01-01

An electron biprism for a 1 million-volt field-emission electron microscope was developed. This biprism is controlled similarly as a specimen holder so that it can be driven and rotated precisely and is tough against mechanical vibration and stray magnetic field. We recorded the maximum number of interference fringes by using this biprism in order to confirm the overall performance as a holography electron microscope, and obtained a world record of 11,000 interference fringes

Glioma cell fate decisions mediated by Dll1-Jag1-Fringe in Notch1 signaling pathway.

Science.gov (United States)

Shi, Xiaofei; Wang, Ruiqi

2017-09-21

The Notch family of proteins plays a vital role in determining cell fates, such as proliferation, differentiation, and apoptosis. It has been shown that Notch1 and its ligands, Dll1 and Jag1, are overexpressed in many glioma cell lines and primary human gliomas. The roles of Notch1 in some cancers have been firmly established, and recent data implicate that it plays important roles in glioma cell fate decisions. This paper focuses on devising a specific theoretical framework that incorporates Dll1, Jag1, and Fringe in Notch1 signaling pathway to explore their functional roles of these proteins in glioma cells in the tumorigenesis and progression of human gliomas, and to study how glioma cell fate decisions are modulated by both trans-activation and cis-inhibition. This paper presents a computational model for Notch1 signaling pathway in glioma cells. Based on the bifurcation analysis of the model, we show that how the glioma cell fate decisions are modulated by both trans-activation and cis-inhibition mediated by the Fringe protein, providing insight into the design and control principles of the Notch signaling system and the gliomas. This paper presents a computational model for Notch1 signaling pathway in glioma cells based on intertwined dynamics with cis-inhibition and trans-activation involving the proteins Notch1, Dll1, Jag1, and Fringe. The results show that how the glioma cell fate transitions are performed by the Notch1 signaling. Transition from grade III ∼ IV with significantly high Notch1 to grade I ∼ II with high Notch1, and then to normal cells by repressing the Fringe levels or decreasing the strength of enhancement induced by Fringe.

Means for maintaining a fixed relative orientation of two sensors

International Nuclear Information System (INIS)

Jubinski, P.

1987-01-01

A sensor module adapted for use in a seismic cable is described comprising: an enclosed housing; a volume of fluid within the housing; a first sensor unit having a specific gravity less than the specific gravity of the fluid and deployed within the housing so that the first sensor unit floats at the top of the fluid as the orientation of the housing changes; a second sensor unit having a specific gravity greater than the specific gravity of the fluid and deployed within the housing so that the second sensor unit remains at the bottom of the fluid as the orientation of the housing changes; a first and second flexible tether securing the first and second sensor units, respectively, to opposite ends of the housing, the tethers including signal conductors for coupling signal from the sensor units to the exterior of the housing

Livelihood trends in Response to Climate Change in Forest Fringe ...

African Journals Online (AJOL)

One of the forest fringe communities in Ghana where the rural livelihoods of the people have been compromised due to deforestation and climate change is the Offin basin. The removal of forests impacts on local climate, water availability, and livelihoods due to influence of forests on precipitation and water balance. Fluxes ...

High-efficiency holograms fixed in lithium niobate after recording using a digital fringe stabilization system.

Science.gov (United States)

Arizmendi, Luis; Ambite, Emilio J

2012-02-20

We used a digital feedback control loop system to produce reproducible fixed volume transmission holograms of high diffraction efficiency. Different strategies were investigated to obtain holograms of good quality and the highest refractive index modulation depth. Using this control system, we were able to record holograms with stationary fringes. Additionally to using the stationary fringe recording, a double recording-fixing schedule resulted in being the most appropriate one to produce reproducible holograms of better characteristics. This strategy is discussed and compared with other already established ones. © 2012 Optical Society of America

Mechanisms of wave‐driven water level variability on reef‐fringed coastlines

Science.gov (United States)

Buckley, Mark L.; Lowe, Ryan J.; Hansen, Jeff E; van Dongeren, Ap R.; Storlazzi, Curt

2018-01-01

Wave‐driven water level variability (and runup at the shoreline) is a significant cause of coastal flooding induced by storms. Wave runup is challenging to predict, particularly along tropical coral reef‐fringed coastlines due to the steep bathymetric profiles and large bottom roughness generated by reef organisms, which can violate assumptions in conventional models applied to open sandy coastlines. To investigate the mechanisms of wave‐driven water level variability on a reef‐fringed coastline, we performed a set of laboratory flume experiments on an along‐shore uniform bathymetric profile with and without bottom roughness. Wave setup and waves at frequencies lower than the incident sea‐swell forcing (infragravity waves) were found to be the dominant components of runup. These infragravity waves were positively correlated with offshore wave groups, signifying they were generated in the surf zone by the oscillation of the breakpoint. On the reef flat and at the shoreline, the low‐frequency waves formed a standing wave pattern with energy concentrated at the natural frequencies of the reef flat, indicating resonant amplification. Roughness elements used in the flume to mimic large reef bottom roughness reduced low frequency motions on the reef flat and reduced wave run up by 30% on average, compared to the runs over a smooth bed. These results provide insight into sea‐swell and infragravity wave transformation and wave setup dynamics on steep‐sloped coastlines, and the effect that future losses of reef bottom roughness may have on coastal flooding along reef‐fringed coasts.

Rigorous bounds on survival times in circular accelerators and efficient computation of fringe-field transfer maps

International Nuclear Information System (INIS)

Hoffstaetter, G.H.

1994-12-01

Analyzing stability of particle motion in storage rings contributes to the general field of stability analysis in weakly nonlinear motion. A method which we call pseudo invariant estimation (PIE) is used to compute lower bounds on the survival time in circular accelerators. The pseudeo invariants needed for this approach are computed via nonlinear perturbative normal form theory and the required global maxima of the highly complicated multivariate functions could only be rigorously bound with an extension of interval arithmetic. The bounds on the survival times are large enough to the relevant; the same is true for the lower bounds on dynamical aperatures, which can be computed. The PIE method can lead to novel design criteria with the objective of maximizing the survival time. A major effort in the direction of rigourous predictions only makes sense if accurate models of accelerators are available. Fringe fields often have a significant influence on optical properties, but the computation of fringe-field maps by DA based integration is slower by several orders of magnitude than DA evaluation of the propagator for main-field maps. A novel computation of fringe-field effects called symplectic scaling (SYSCA) is introduced. It exploits the advantages of Lie transformations, generating functions, and scaling properties and is extremely accurate. The computation of fringe-field maps is typically made nearly two orders of magnitude faster. (orig.)

Generation of sinusoidal fringes with a holographic phase grating and a phase-only spatial light modulator

International Nuclear Information System (INIS)

Berberova, Natalia; Stoykova, Elena; Sainov, Ventseslav

2012-01-01

A variety of pattern projection methods for the three-dimensional capture of objects is based on the generation of purely sinusoidal fringes. This is not an easy task, especially when a portable non-interferometric system for outdoor usage is required. The use of phase gratings with coherent illumination as a possible solution has the advantage of providing good stability and a large measurement volume. In this work, we analyze the quality of fringes projected with two sinusoidal phase gratings. The first grating is recorded on a silver-halide holographic plate by means of a Michelson interferometer. The spatial resolution of the silver-halide material used is greater than 6000 lines per millimeter, and the recorded grating is practically analogous to a smooth variation of the phase profile. The second grating is formed as a sinusoidal phase variation on a liquid crystal-on-silicon phase-only reflective display with a resolution of 1920×1080 pixels, a pixel pitch of 8 μm and 256 phase levels. The frequency content of the fringes projected with both gratings is analyzed and compared on the basis of the calculated Fresnel diffraction pattern, taking into account that the sinusoidal phase distribution in the case of a spatial light modulator is both sampled and quantized. Experimental fringe patterns projected using both gratings are also provided.

A novel dual-functional MEMS sensor integrating both pressure and temperature units

Energy Technology Data Exchange (ETDEWEB)

Chen Tao; Zhang Zhaohua; Ren Tianling; Miao Gujin; Zhou Changjian; Lin Huiwang; Liu Litian, E-mail: RenTL@tsinghua.edu.c [National Laboratory for Information Science and Technology, Institute of Microelectronics, Tsinghua University, Beijing 100084 (China)

2010-07-15

This paper proposes a novel miniature dual-functional sensor integrating both pressure and temperature sensitive units on a single chip. The device wafer of SOI is used as a pizeoresistive diaphragm which features excellent consistency in thickness. The conventional anisotropic wet etching has been abandoned, while ICP etching has been employed to etch out the reference cave to minimize the area of individual device in the way that the 57.4{sup 0} slope has been eliminated. As a result, the average cost of the single chip is reduced. Two PN junctions with constant ratio of the areas of depletion regions have also been integrated on the same chip to serve as a temperature sensor, and each PN junction shows high linearity over -40 to 100 {sup 0}C and low power consumption. The iron implanting process for PN junction is exactly compatible with the piezoresistor, with no additional expenditure. The pressure sensitivity is 86 mV/MPa, while temperature sensitivity is 1.43 mV/{sup 0}C, both complying with the design objective.

A novel dual-functional MEMS sensor integrating both pressure and temperature units

International Nuclear Information System (INIS)

Chen Tao; Zhang Zhaohua; Ren Tianling; Miao Gujin; Zhou Changjian; Lin Huiwang; Liu Litian

2010-01-01

This paper proposes a novel miniature dual-functional sensor integrating both pressure and temperature sensitive units on a single chip. The device wafer of SOI is used as a pizeoresistive diaphragm which features excellent consistency in thickness. The conventional anisotropic wet etching has been abandoned, while ICP etching has been employed to etch out the reference cave to minimize the area of individual device in the way that the 57.4 0 slope has been eliminated. As a result, the average cost of the single chip is reduced. Two PN junctions with constant ratio of the areas of depletion regions have also been integrated on the same chip to serve as a temperature sensor, and each PN junction shows high linearity over -40 to 100 0 C and low power consumption. The iron implanting process for PN junction is exactly compatible with the piezoresistor, with no additional expenditure. The pressure sensitivity is 86 mV/MPa, while temperature sensitivity is 1.43 mV/ 0 C, both complying with the design objective.

An enhanced ionising radiation monitoring and detecting technique in radiotherapy units of hospitals using wireless sensor networks

International Nuclear Information System (INIS)

Ali, Peter

2017-01-01

In this paper, a solution of ionising radiation monitoring based on the concept of Wireless Sensor Network (WSN), is presented. Radiation dose rate measured by the sensor node is sent to the monitoring station through ZigBee wireless network operated on 2.4 GHz unlicensed Industrial Scientific Medical (ISM) band. The system is calibrated for use for ionizing radiation dose rate range of between amount of ionising radiation observed in radiotherapy unit of a hospital and 1.02 mSv/h. Power consumption of the sensor node is kept low by operating the node ZigBee radio with low duty cycle: i.e. by keeping the radio awake only during data transmission/reception. Two ATmega8 microcontrollers, one each for sensor node and the monitoring station, are programmed to perform interfacing, data processing, and control functions. The system range of coverage is 124m for outdoor (line of site) deployment and 56.8m for indoor application where 5 brick walls separated the sensor node and the monitoring station. Range of coverage of the system is extendable via the use of ZigBee router (s)

Fast fringe-field switching of a liquid crystal cell by two-dimensional confinement with virtual walls

OpenAIRE

Choi, Tae-Hoon; Oh, Seung-Won; Park, Young-Jin; Choi, Yeongyu; Yoon, Tae-Hoon

2016-01-01

We report a simple method for reducing the response time of a fringe-field switching liquid crystal cell by using two-dimensional confinement of the liquid crystals. Through both numerical calculations and experiments, we show that the switching speed can be increased by several fold in a fringe-field switching cell by simply using a rubbing angle of zero, which causes virtual walls to be built when an electric field is applied between the interdigitated electrodes and the common electrode, w...

The shelf space and strategic placement of healthy and discretionary foods in urban, urban-fringe and rural/non-metropolitan Australian supermarkets.

Science.gov (United States)

Cameron, Adrian J

2018-02-01

Supermarkets are a key influence on eating behaviours, but it is unknown if the promotion of food within stores varies on a geographic gradient from urban, to urban-fringe and non-metropolitan areas. The present study aimed to assess the shelf space and strategic placement of healthy and discretionary foods in each of urban, urban-fringe and non-metropolitan Australian supermarkets. Design/Setting In-store audits were conducted in stores from one of the two major Australian supermarket chains in urban (n 19), urban-fringe (n 20) and non-metropolitan (n 26) areas of Victoria. These audits examined selected food items (crisps/chips, chocolate, confectionery, soft drinks/sodas, fruits and vegetables) and measured the shelf space and the proportion of end-of-aisle and cash register displays containing these products. Store size was measured as the sum of aisle length. Differences in the supermarket food environment with respect to location were assessed, before and after adjustment for neighbourhood socio-economic position. The strategic placement of discretionary foods was commonly observed in all supermarkets. Adjusting for store size (larger in urban-fringe and rural areas), urban stores had greater shelf space devoted to fruits and vegetables, and less checkouts with soft drinks, than urban-fringe and rural/non-metropolitan areas. Differences remained following adjustment for neighbourhood socio-economic position. No clear pattern was observed for end-of-aisle displays, or the placement of chocolate and confectionery at checkouts. The shelf space of healthy and discretionary foods in urban-fringe and rural stores parallels the prevalence of overweight and obesity in these areas. Interventions in urban-fringe and rural stores targeting the shelf space of healthy foods and the placement of soft drinks at key displays may be useful obesity prevention initiatives.

Multiparametric methane sensor for environmental monitoring

Science.gov (United States)

Borecki, M.; Duk, M.; Kociubiński, A.; Korwin-Pawlowski, M. L.

2016-12-01

Today, methane sensors find applications mostly in safety alarm installations, gas parameters detection and air pollution classification. Such sensors and sensors elements exists for industry and home use. Under development area of methane sensors application is dedicated to ground gases monitoring. Proper monitoring of soil gases requires reliable and maintenance-free semi-constant and longtime examination at relatively low cost of equipment. The sensors for soil monitoring have to work on soil probe. Therefore, sensor is exposed to environment conditions, as a wide range of temperatures and a full scale of humidity changes, as well as rain, snow and wind, that are not specified for classical methane sensors. Development of such sensor is presented in this paper. The presented sensor construction consists of five commercial non dispersive infra-red (NDIR) methane sensing units, a set of temperature and humidity sensing units, a gas chamber equipped with a micro-fan, automated gas valves and also a microcontroller that controls the measuring procedure. The electronics part of sensor was installed into customized 3D printed housing equipped with self-developed gas valves. The main development of proposed sensor is on the side of experimental evaluation of construction reliability and results of data processing included safety procedures and function for hardware error correction. Redundant methane sensor units are used providing measurement error correction as well as improved measurement accuracy. The humidity and temperature sensors are used for internal compensation of methane measurements as well as for cutting-off the sensor from the environment when the conditions exceed allowable parameters. Results obtained during environment sensing prove that the gas concentration readings are not sensitive to gas chamber vertical or horizontal position. It is important as vertical sensor installation on soil probe is simpler that horizontal one. Data acquired during six

Diffraction of a Gaussian laser beam by a straight edge leading to the formation of optical vortices and elliptical diffraction fringes

Science.gov (United States)

Zeylikovich, Iosif; Nikitin, Aleksandr

2018-04-01

The diffraction of a Gaussian laser beam by a straight edge has been studied theoretically and experimentally for many years. In this paper, we have experimentally observed for the first time the formation of the cusped caustic (for the Fresnel number F ≈ 100) in the shadow region of the straight edge, with the cusp placed near the center of the circular laser beam(λ = 0 . 65 μm) overlapped with the elliptical diffraction fringes. These fringes are originated at the region near the cusp of the caustic where light intensity is zero and the wave phase is singular (the optical vortex). We interpret observed diffraction fringes as a result of interference between the helical wave created by the optical vortex and cylindrical wave diffracted at the straight edge. We have theoretically revealed that the number of high contrast diffraction fringes observable in a shadow region is determined by the square of the diffracted angles in the range of spatial frequencies of the scattered light field in excellent agreement with experiments. The extra phase singularities with opposite charges are also observed along the shadow boundary as the fork-like diffraction fringes.

Localization and Tracking of Implantable Biomedical Sensors

Directory of Open Access Journals (Sweden)

Ilknur Umay

2017-03-01

Full Text Available Implantable sensor systems are effective tools for biomedical diagnosis, visualization and treatment of various health conditions, attracting the interest of researchers, as well as healthcare practitioners. These systems efficiently and conveniently provide essential data of the body part being diagnosed, such as gastrointestinal (temperature, pH, pressure parameter values, blood glucose and pressure levels and electrocardiogram data. Such data are first transmitted from the implantable sensor units to an external receiver node or network and then to a central monitoring and control (computer unit for analysis, diagnosis and/or treatment. Implantable sensor units are typically in the form of mobile microrobotic capsules or implanted stationary (body-fixed units. In particular, capsule-based systems have attracted significant research interest recently, with a variety of applications, including endoscopy, microsurgery, drug delivery and biopsy. In such implantable sensor systems, one of the most challenging problems is the accurate localization and tracking of the microrobotic sensor unit (e.g., robotic capsule inside the human body. This article presents a literature review of the existing localization and tracking techniques for robotic implantable sensor systems with their merits and limitations and possible solutions of the proposed localization methods. The article also provides a brief discussion on the connection and cooperation of such techniques with wearable biomedical sensor systems.

Holographic images reconstructed from GMR-based fringe pattern

Directory of Open Access Journals (Sweden)

Kikuchi Hiroshi

2013-01-01

Full Text Available We have developed a magneto-optical spatial light modulator (MOSLM using giant magneto-resistance (GMR structures for realizing a holographic three-dimensional (3D display. For practical applications, reconstructed image of hologram consisting of GMR structures should be investigated in order to study the feasibility of the MOSLM. In this study, we fabricated a hologram with GMR based fringe-pattern and demonstrated a reconstructed image. A fringe-pattern convolving a crossshaped image was calculated by a conventional binary computer generated hologram (CGH technique. The CGH-pattern has 2,048 × 2,048 with 5 μm pixel pitch. The GMR stack consists of a Tb-Fe-Co/CoFe pinned layer, a Ag spacer, a Gd-Fe free layer for light modulation, and a Ru capping layer, was deposited by dc-magnetron sputtering. The GMR hologram was formed using photo-lithography and Krion milling processes, followed by the deposition of a Tb-Fe-Co reference layer with large coercivity and the same Kerr-rotation angle compared to the free layer, and a lift-off process. The reconstructed image of the ON-state was clearly observed and successfully distinguished from the OFF-state by switching the magnetization direction of the free-layer with an external magnetic field. These results indicate the possibility of realizing a holographic 3D display by the MOSLM using the GMR structures.

A Flexible Fringe Projection Vision System with Extended Mathematical Model for Accurate Three-Dimensional Measurement.

Science.gov (United States)

Xiao, Suzhi; Tao, Wei; Zhao, Hui

2016-04-28

In order to acquire an accurate three-dimensional (3D) measurement, the traditional fringe projection technique applies complex and laborious procedures to compensate for the errors that exist in the vision system. However, the error sources in the vision system are very complex, such as lens distortion, lens defocus, and fringe pattern nonsinusoidality. Some errors cannot even be explained or rendered with clear expressions and are difficult to compensate directly as a result. In this paper, an approach is proposed that avoids the complex and laborious compensation procedure for error sources but still promises accurate 3D measurement. It is realized by the mathematical model extension technique. The parameters of the extended mathematical model for the 'phase to 3D coordinates transformation' are derived using the least-squares parameter estimation algorithm. In addition, a phase-coding method based on a frequency analysis is proposed for the absolute phase map retrieval to spatially isolated objects. The results demonstrate the validity and the accuracy of the proposed flexible fringe projection vision system on spatially continuous and discontinuous objects for 3D measurement.

APPLICATION OF THE NATURALLY-OCCURRING DEUTERIUM ISOTOPE TO TRACING THE CAPILLARY FRINGE

Science.gov (United States)

Naturally-occurring deuterium is a useful tracer of subsurface hydrologic processes. A possible application includes the identification of capillary fringes in the vadose zone. Multiple and discontinuous water tables persist in many temperate regions, under various hydrogeologi...

Actors and processes behind urban fringe development: Mechanism to guide urban land management. Study on Dhaka, Bangladesh

OpenAIRE

Masum, Fahria

2009-01-01

This thesis has attempted to analyze and resolve urban fringe problems in Dhaka by incorporating different roles and interests of actors in land development processes. The research has revealed that these different actors have different interests, norms and ideologies which are playing an active role in guiding or regulating urban land development process. This situation is deploying existing rules and regulations in form of politics and affecting urban fringe management negatively. The resea...

Nanowire sensor, sensor array, and method for making the same

Science.gov (United States)

Yun, Minhee (Inventor); Myung, Nosang (Inventor); Vasquez, Richard (Inventor); Homer, Margie (Inventor); Ryan, Margaret (Inventor); Yen, Shiao-Pin (Inventor); Fleurial, Jean-Pierre (Inventor); Bugga, Ratnakumar (Inventor); Choi, Daniel (Inventor); Goddard, William (Inventor)

2012-01-01

The present invention relates to a nanowire sensor and method for forming the same. More specifically, the nanowire sensor comprises at least one nanowire formed on a substrate, with a sensor receptor disposed on a surface of the nanowire, thereby forming a receptor-coated nanowire. The nanowire sensor can be arranged as a sensor sub-unit comprising a plurality of homogeneously receptor-coated nanowires. A plurality of sensor subunits can be formed to collectively comprise a nanowire sensor array. Each sensor subunit in the nanowire sensor array can be formed to sense a different stimulus, allowing a user to sense a plurality of stimuli. Additionally, each sensor subunit can be formed to sense the same stimuli through different aspects of the stimulus. The sensor array is fabricated through a variety of techniques, such as by creating nanopores on a substrate and electrodepositing nanowires within the nanopores.

Land Use Land Cover Change in the fringe of eThekwini ...

African Journals Online (AJOL)

Concerns on urban environmental quality, increasing knowledge on impacts of climate change and pursuit for sustainable development have increased the need for past, current and future knowledge on the transformation of remnant urban fringe green ecosystems. Using land-cover change modeler and a Markov chain ...

Fringe field interference of neighbor magnets in China spallation neutron source

International Nuclear Information System (INIS)

Li, L.; Kang, W.; Wu, X.; Deng, C.D.; Li, S.; Yang, M.; Zhou, J.X.; Liu, Y.Q.; Wu, Y.W.

2016-01-01

In CSNS accelerator construction, the field measurement of all RCS magnets have been finished and the magnets have been installed in the tunnel before the end of 2015. The electromagnetic quadrupoles have a large aperture and the core-to-core distance between magnets is rather short in some places. The corrector magnet or the sextupole magnet is closer to one of the quadrupole magnets which caused certain interference. The interference caused by magnetic fringe field has been appeared and it becomes a significant issue in beam dynamics for beam loss control in this high-intensity proton accelerator. We have performed 3D computing simulations to study integral field distributions between the quadrupole and the corrector magnets, and the sextupole and the other quadrupole magnets. The effect of the magnetic fringe field and the interference has been investigated with different distances of the neighbor magnets. The simulation and the field measurement results will be introduced in this paper.

Modeling the static fringe field of superconducting magnets.

Science.gov (United States)

Jeglic, P; Lebar, A; Apih, T; Dolinsek, J

2001-05-01

The resonance frequency-space and the frequency gradient-space relations are evaluated analytically for the static fringe magnetic field of superconducting magnets used in the NMR diffusion measurements. The model takes into account the actual design of the high-homogeneity magnet coil system that consists of the main coil and the cryoshim coils and enables a precise calibration of the on-axis magnetic field gradient and the resonance frequency inside and outside of the superconducting coil. Copyright 2001 Academic Press.

Optical seismic sensor systems and methods

Science.gov (United States)

Beal, A. Craig; Cummings, Malcolm E.; Zavriyev, Anton; Christensen, Caleb A.; Lee, Keun

2015-12-08

Disclosed is an optical seismic sensor system for measuring seismic events in a geological formation, including a surface unit for generating and processing an optical signal, and a sensor device optically connected to the surface unit for receiving the optical signal over an optical conduit. The sensor device includes at least one sensor head for sensing a seismic disturbance from at least one direction during a deployment of the sensor device within a borehole of the geological formation. The sensor head includes a frame and a reference mass attached to the frame via at least one flexure, such that movement of the reference mass relative to the frame is constrained to a single predetermined path.

Theoretical fringe profiles with crossed Babinet compensators in testing concave aspheric surfaces.

Science.gov (United States)

Saxena, A K; Lancelot, J P

1982-11-15

This paper presents the theory for the use of crossed Babinet compensators in testing concave aspheric surfaces. Theoretical fringe profiles for a sphere and for an aspheric surface with primary aberration are shown. Advantages of this method are discussed.

Fourier fringe analysis and its application to metrology of extreme physical phenomena: a review [Invited].

Science.gov (United States)

Takeda, Mitsuo

2013-01-01

The paper reviews a technique for fringe analysis referred to as Fourier fringe analysis (FFA) or the Fourier transform method, with a particular focus on its application to metrology of extreme physical phenomena. Examples include the measurement of extremely small magnetic fields with subfluxon sensitivity by electron wave interferometry, subnanometer wavefront evaluation of projection optics for extreme UV lithography, the detection of sub-Ångstrom distortion of a crystal lattice, and the measurement of ultrashort optical pulses in the femotsecond to attosecond range, which show how the advantages of FFA are exploited in these cutting edge applications.

The Acropora inheritance: A reinterpretation of the development of fringing reefs in Barbados, West Indies

Science.gov (United States)

Lewis, John B.

1984-11-01

The discovery of the widespread occurrence of the remains of the reef coral Acropora palmata within the fabric of the fringing reefs on the west coast of Barbados requires a new interpretation of their Holocene development. Radiocarbon dating of the A. palmata framework suggests that reef construction by this species began as early as 2,300 years B.P. A. palmata probably flourished in Barbados into the present century but has now declined. The present fringing reefs are characterized by a core and base of A. palmata upon which subsequent colonization took place, especially by Montastrea annularis, Porites porites and coralline algae.

Design of an Integrated Sensor Platform for Vital Sign Monitoring of Newborn Infants at Neonatal Intensive Care Units

Directory of Open Access Journals (Sweden)

Wei Chen

2010-01-01

Full Text Available Continuous health status monitoring and advances in medical treatments have resulted in a significant increase of survival rate in critically ill infants admitted into Neonatal Intensive Care Units (NICUs. The quality of life and long-term health prospects of the neonates depend increasingly on the reliability and comfort of the monitoring systems. In this paper, we present the design work of a smart jacket for vital sign monitoring of neonates at a NICU. The design represents a unique integration of sensor technology, user focus and design aspects. Textile sensors, a reflectance pulse oximeter and a wearable temperature sensor were proposed to be embedded into the smart jacket. Location of the sensor, materials and appearance were designed to optimize the functionality, patient comfort and the possibilities for aesthetic features. Prototypes were built for demonstrating the design concept and experimental results were obtained from tests on premature babies at the NICU of M�xima Medical Centre (MMC in Veldhoven, the Netherlands.

Profilometry of discontinuous solids by means of co-phased demodulation of projected fringes with RGB encoding

Science.gov (United States)

Padilla, J. M.; Servin, M.; Garnica, G.

2015-05-01

Here we describe a 2-projectors and 1-camera setup for profilometry of discontinuous solids by means of co-phased demodulation of projected fringes and red, green, and blue (RGB) multichannel operation. The dual projection configuration for this profilometer is proposed to solve efficiently specular regions and self-occluding shadows due to discontinuities, which are the main drawbacks for a 1-projector 1-camera configuration. This is because the regions where shadows and specular reflections are generated, and the fringe contrast drops to zero, are in general different for each projection direction; thus, the resulting fringe patterns will have complementary phase information. Multichannel RGB operation allows us to work simultaneously with both projectors and to record independently the complementary fringe patterns phase-modulated by the 3D profile of the object under study. In other words, color encoding/decoding reduces the acquisition time respect to one-at-a-time grayscale operation and, in principle, enables the study of dynamic phenomena. The co-phased demodulation method implemented in this work benefits from the complex (analytic) nature of the output signals estimated with most phase demodulation methods (such as the Fourier method, and temporal phaseshifting algorithms). This allowed us to straightforwardly generate a single phase-map well-defined for the entire area of interest. Finally we assessed our proposed profilometry setup by measuring a fractured spherical cap made of (uncoated) expanded polystyrene. The results were satisfactory but in the authors' opinion this must be considered a preliminary report.

Anti-spoof touchless 3D fingerprint recognition system using single shot fringe projection and biospeckle analysis

Science.gov (United States)

Chatterjee, Amit; Bhatia, Vimal; Prakash, Shashi

2017-08-01

Fingerprint is a unique, un-alterable and easily collected biometric of a human being. Although it is a 3D biological characteristic, traditional methods are designed to provide only a 2D image. This touch based mapping of 3D shape to 2D image losses information and leads to nonlinear distortions. Moreover, as only topographic details are captured, conventional systems are potentially vulnerable to spoofing materials (e.g. artificial fingers, dead fingers, false prints, etc.). In this work, we demonstrate an anti-spoof touchless 3D fingerprint detection system using a combination of single shot fringe projection and biospeckle analysis. For fingerprint detection using fringe projection, light from a low power LED source illuminates a finger through a sinusoidal grating. The fringe pattern modulated because of features on the fingertip is captured using a CCD camera. Fourier transform method based frequency filtering is used for the reconstruction of 3D fingerprint from the captured fringe pattern. In the next step, for spoof detection using biospeckle analysis a visuo-numeric algorithm based on modified structural function and non-normalized histogram is proposed. High activity biospeckle patterns are generated because of interaction of collimated laser light with internal fluid flow of the real finger sample. This activity reduces abruptly in case of layered fake prints, and is almost absent in dead or fake fingers. Furthermore, the proposed setup is fast, low-cost, involves non-mechanical scanning and is highly stable.

A New Facility for Testing Superconducting Solenoid Magnets with Large Fringe Fields at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Orris, D. [Fermilab; Carcagno, R. [Fermilab; Nogiec, J. [Fermilab; Rabehl, R. [Fermilab; Sylvester, C. [Fermilab; Tartaglia, M. [Fermilab

2013-09-01

Testing superconducting solenoid with no iron flux return can be problematic for a magnet test facility due to the large magnetic fringe fields generated. These large external fields can interfere with the operation of equipment while precautions must be taken for personnel supporting the test. The magnetic forces between the solenoid under test and the external infrastructure must also be taken under consideration. A new test facility has been designed and built at Fermilab specifically for testing superconducting magnets with large external fringe fields. This paper discusses the test stand design, capabilities, and details of the instrumentation and controls with data from the first solenoid tested in this facility: the Muon Ionization Cooling Experiment (MICE) coupling coil.

The Apical Actin Fringe Contributes to Localized Cell Wall Deposition and Polarized Growth in the Lily Pollen Tube1[W][OPEN

Science.gov (United States)

Rounds, Caleb M.; Hepler, Peter K.; Winship, Lawrence J.

2014-01-01

In lily (Lilium formosanum) pollen tubes, pectin, a major component of the cell wall, is delivered through regulated exocytosis. The targeted transport and secretion of the pectin-containing vesicles may be controlled by the cortical actin fringe at the pollen tube apex. Here, we address the role of the actin fringe using three different inhibitors of growth: brefeldin A, latrunculin B, and potassium cyanide. Brefeldin A blocks membrane trafficking and inhibits exocytosis in pollen tubes; it also leads to the degradation of the actin fringe and the formation of an aggregate of filamentous actin at the base of the clear zone. Latrunculin B, which depolymerizes filamentous actin, markedly slows growth but allows focused pectin deposition to continue. Of note, the locus of deposition shifts frequently and correlates with changes in the direction of growth. Finally, potassium cyanide, an electron transport chain inhibitor, briefly stops growth while causing the actin fringe to completely disappear. Pectin deposition continues but lacks focus, instead being delivered in a wide arc across the pollen tube tip. These data support a model in which the actin fringe contributes to the focused secretion of pectin to the apical cell wall and, thus, to the polarized growth of the pollen tube. PMID:25037212

Modeling of the fringe shift in multiple beam interference for glass ...

Indian Academy of Sciences (India)

An experiment is conducted using liquid wedge interferometer where the fiber of a nearly quadratic .... For a fringe shift dz < ∆z, we obtain this inequality. µf − µL < λt2 .... [11] L M Boggs, H M Presby and D Marcuse, Bell System Tech. J. 58, 867 ...

Western Pairie Fringed Orchid: Its Status, Ecology, and in Vitro Propagation

Science.gov (United States)

Jyotsna Sharma; J. W. Van Sambeek; Christopher J. Starbuck

2002-01-01

Western prairie fringed orchid (Platanthera praeclara Sheviak and Bowles), listed in 1989 as federally threatened, has been extirpated from 75% of historic sites throughout its range. We describe (a) threats to the orchid; (b) seed germination on synthetic medium; and (c) in vitro germination with mycorrhizal fungi. Destruction of prairies for...

Boussinesq Modeling of Wave Propagation and Runup over Fringing Coral Reefs, Model Evaluation Report

National Research Council Canada - National Science Library

Demirbilek, Zeki; Nwogu, Okey G

2007-01-01

..., for waves propagating over fringing reefs. The model evaluation had two goals: (a) investigate differences between laboratory and field characteristics of wave transformation processes over reefs, and (b...

A Flexible Fringe Projection Vision System with Extended Mathematical Model for Accurate Three-Dimensional Measurement

Directory of Open Access Journals (Sweden)

Suzhi Xiao

2016-04-01

Full Text Available In order to acquire an accurate three-dimensional (3D measurement, the traditional fringe projection technique applies complex and laborious procedures to compensate for the errors that exist in the vision system. However, the error sources in the vision system are very complex, such as lens distortion, lens defocus, and fringe pattern nonsinusoidality. Some errors cannot even be explained or rendered with clear expressions and are difficult to compensate directly as a result. In this paper, an approach is proposed that avoids the complex and laborious compensation procedure for error sources but still promises accurate 3D measurement. It is realized by the mathematical model extension technique. The parameters of the extended mathematical model for the ’phase to 3D coordinates transformation’ are derived using the least-squares parameter estimation algorithm. In addition, a phase-coding method based on a frequency analysis is proposed for the absolute phase map retrieval to spatially isolated objects. The results demonstrate the validity and the accuracy of the proposed flexible fringe projection vision system on spatially continuous and discontinuous objects for 3D measurement.

Applicability of Neural Networks to Etalon Fringe Filtering in Laser Spectrometers

Science.gov (United States)

Nicely, J. M.; Hanisco, T. F.; Riris, H.

2018-01-01

We present a neural network algorithm for spectroscopic retrievals of concentrations of trace gases. Using synthetic data we demonstrate that a neural network is well suited for filtering etalon fringes and provides superior performance to conventional least squares minimization techniques. This novel method can improve the accuracy of atmospheric retrievals and minimize biases.

Applicability of neural networks to etalon fringe filtering in laser spectrometers

Science.gov (United States)

Nicely, J. M.; Hanisco, T. F.; Riris, H.

2018-05-01

We present a neural network algorithm for spectroscopic retrievals of concentrations of trace gases. Using synthetic data we demonstrate that a neural network is well suited for filtering etalon fringes and provides superior performance to conventional least squares minimization techniques. This novel method can improve the accuracy of atmospheric retrievals and minimize biases.

Directly Measuring the Degree of Quantum Coherence using Interference Fringes

Science.gov (United States)

Wang, Yi-Tao; Tang, Jian-Shun; Wei, Zhi-Yuan; Yu, Shang; Ke, Zhi-Jin; Xu, Xiao-Ye; Li, Chuan-Feng; Guo, Guang-Can

2017-01-01

Quantum coherence is the most distinguished feature of quantum mechanics. It lies at the heart of the quantum-information technologies as the fundamental resource and is also related to other quantum resources, including entanglement. It plays a critical role in various fields, even in biology. Nevertheless, the rigorous and systematic resource-theoretic framework of coherence has just been developed recently, and several coherence measures are proposed. Experimentally, the usual method to measure coherence is to perform state tomography and use mathematical expressions. Here, we alternatively develop a method to measure coherence directly using its most essential behavior—the interference fringes. The ancilla states are mixed into the target state with various ratios, and the minimal ratio that makes the interference fringes of the "mixed state" vanish is taken as the quantity of coherence. We also use the witness observable to witness coherence, and the optimal witness constitutes another direct method to measure coherence. For comparison, we perform tomography and calculate l1 norm of coherence, which coincides with the results of the other two methods in our situation. Our methods are explicit and robust, providing a nice alternative to the tomographic technique.

Fibre optic strain sensor: examples of applications

Science.gov (United States)

Kruszewski, J.; Beblowska, M.; Wrzosek, P.

2006-03-01

Construction of strain sensor for application in safety systems has been presented. The device consists of sensor's head and source and detector units. The head is made of polymer fiber bends. Designed sensor could be mounted in monitoring place (e.g. under a floor) and controlled by PC unit or could be used as a portable device for a valuable object protection.

Preferred sensor sites for surface EMG signal decomposition

International Nuclear Information System (INIS)

Zaheer, Farah; Roy, Serge H; De Luca, Carlo J

2012-01-01

Technologies for decomposing the electromyographic (EMG) signal into its constituent motor unit action potential trains have become more practical by the advent of a non-invasive methodology using surface EMG (sEMG) sensors placed on the skin above the muscle of interest (De Luca et al 2006 J. Neurophysiol. 96 1646–57 and Nawab et al 2010 Clin. Neurophysiol. 121 1602–15). This advancement has widespread appeal among researchers and clinicians because of the ease of use, reduced risk of infection, and the greater number of motor unit action potential trains obtained compared to needle sensor techniques. In this study we investigated the influence of the sensor site on the number of identified motor unit action potential trains in six lower limb muscles and one upper limb muscle with the intent of locating preferred sensor sites that provided the greatest number of decomposed motor unit action potential trains, or motor unit yield. Sensor sites rendered varying motor unit yields throughout the surface of a muscle. The preferred sites were located between the center and the tendinous areas of the muscle. The motor unit yield was positively correlated with the signal-to-noise ratio of the detected sEMG. The signal-to-noise ratio was inversely related to the thickness of the tissue between the sensor and the muscle fibers. A signal-to-noise ratio of 3 was found to be the minimum required to obtain a reliable motor unit yield. (paper)

Transport-related fringe benefits: implications for moving and the journey to work

NARCIS (Netherlands)

van Ommeren, J.N.; van der Vlist, A.J.; Nijkamp, P.

2006-01-01

Firms offer compensation not only through wages, but also offer transport-related fringe benefits such as transport benefits (company cars, travel, and parking benefits) and relocation benefits to job applicants. We argue that these benefits are not randomly offered to employees, but depend on the

Activity Recognition Invariant to Sensor Orientation with Wearable Motion Sensors.

Science.gov (United States)

Yurtman, Aras; Barshan, Billur

2017-08-09

Most activity recognition studies that employ wearable sensors assume that the sensors are attached at pre-determined positions and orientations that do not change over time. Since this is not the case in practice, it is of interest to develop wearable systems that operate invariantly to sensor position and orientation. We focus on invariance to sensor orientation and develop two alternative transformations to remove the effect of absolute sensor orientation from the raw sensor data. We test the proposed methodology in activity recognition with four state-of-the-art classifiers using five publicly available datasets containing various types of human activities acquired by different sensor configurations. While the ordinary activity recognition system cannot handle incorrectly oriented sensors, the proposed transformations allow the sensors to be worn at any orientation at a given position on the body, and achieve nearly the same activity recognition performance as the ordinary system for which the sensor units are not rotatable. The proposed techniques can be applied to existing wearable systems without much effort, by simply transforming the time-domain sensor data at the pre-processing stage.

Novel Method of Detecting Movement of the Interference Fringes Using One-Dimensional PSD

Directory of Open Access Journals (Sweden)

Qi Wang

2015-06-01

Full Text Available In this paper, a method of using a one-dimensional position-sensitive detector (PSD by replacing charge-coupled device (CCD to measure the movement of the interference fringes is presented first, and its feasibility is demonstrated through an experimental setup based on the principle of centroid detection. Firstly, the centroid position of the interference fringes in a fiber Mach-Zehnder (M-Z interferometer is solved in theory, showing it has a higher resolution and sensitivity. According to the physical characteristics and principles of PSD, a simulation of the interference fringe’s phase difference in fiber M-Z interferometers and PSD output is carried out. Comparing the simulation results with the relationship between phase differences and centroid positions in fiber M-Z interferometers, the conclusion that the output of interference fringes by PSD is still the centroid position is obtained. Based on massive measurements, the best resolution of the system is achieved with 5.15, 625 μm. Finally, the detection system is evaluated through setup error analysis and an ultra-narrow-band filter structure. The filter structure is configured with a one-dimensional photonic crystal containing positive and negative refraction material, which can eliminate background light in the PSD detection experiment. This detection system has a simple structure, good stability, high precision and easily performs remote measurements, which makes it potentially useful in material small deformation tests, refractivity measurements of optical media and optical wave front detection.

Battery management system with distributed wireless sensors

Science.gov (United States)

Farmer, Joseph C.; Bandhauer, Todd M.

2016-02-23

A system for monitoring parameters of an energy storage system having a multiplicity of individual energy storage cells. A radio frequency identification and sensor unit is connected to each of the individual energy storage cells. The radio frequency identification and sensor unit operates to sense the parameter of each individual energy storage cell and provides radio frequency transmission of the parameters of each individual energy storage cell. A management system monitors the radio frequency transmissions from the radio frequency identification and sensor units for monitoring the parameters of the energy storage system.

Investigating excitation-dependent and fringe-field effects of electromagnet and permanent-magnet phase shifters for a crossed undulator

Energy Technology Data Exchange (ETDEWEB)

Chung, Ting-Yi, E-mail: chung.albert@nsrrc.org.tw [National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Yang, Chih-Sheng; Chu, Yun-Liang; Lin, Fu-Yuan; Jan, Jyh-Chyuan [National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Hwang, Ching-Shiang [National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Department of Electrophysics, National Chiao Tung University, Hsinchu 30050, Taiwan (China)

2017-04-01

To enhance the flux density or to control polarization, a phase shifter was designed and used to modulate the phase matching between segmented undulators. A larger hysteresis loop causes, however, a repeatability issue in the phase matching; the fringe field of the phase shifter creates an extra magnetic-field error. The design of the phase shifter must therefore minimize the hysteresis loop and fringe field to maintain the phases exact and to ignore the crosstalk effect. Two critical issues are the hysteresis-loop problem and the fringe-field effect, which determine the radiation performance and the stability of the ring. To investigate these issues, a phase shifter was constructed to operate in accordance with electromagnetic- and permanent-type magnets; the results from the field measurements and shims are discussed here. The shimming algorithm and a compact permanent-magnet phase shifter that eliminates the issues are also presented.

NEW OPTICAL SENSOR SUITE FOR ULTRAHIGH TEMPERATURE FOSSIL FUEL APPLICATIONS

Energy Technology Data Exchange (ETDEWEB)

Russell G. May; Tony Peng; Tom Flynn

2004-12-01

Accomplishments during the Phase I of a program to develop and demonstrate technology for the instrumentation of advanced powerplants are described. Engineers from Prime Research, LC and Babcock and Wilcox Research Center collaborated to generate a list of potential applications for robust photonic sensors in existing and future boiler plants. From that list, three applications were identified as primary candidates for initial development and demonstration of high-temperature sensors in an ultrasupercritical power plant. A matrix of potential fiber optic sensor approaches was derived, and a data set of specifications for high-temperature optical fiber was produced. Several fiber optic sensor configurations, including interferometric (extrinsic and intrinsic Fabry-Perot interferometer), gratings (fiber Bragg gratings and long period gratings), and microbend sensors, were evaluated in the laboratory. In addition, progress was made in the development of materials and methods to apply high-temperature optical claddings to sapphire fibers, in order to improve their optical waveguiding properties so that they can be used in the design and fabrication of high-temperature sensors. Through refinements in the processing steps, the quality of the interface between core and cladding of the fibers was improved, which is expected to reduce scattering and attenuation in the fibers. Numerical aperture measurements of both clad and unclad sapphire fibers were obtained and used to estimate the reduction in mode volume afforded by the cladding. High-temperature sensors based on sapphire fibers were also investigated. The fabrication of an intrinsic Fabry-Perot cavity within sapphire fibers was attempted by the bulk diffusion of magnesium oxide into short localized segments of longer sapphire fibers. Fourier analysis of the fringes that resulted when the treated fiber was interrogated by a swept laser spectrometer suggested that an intrinsic cavity had been formed in the fiber. Also

[Heat vulnerability assessment in Jinan city: a comparison between residents living in urban centers and urban-fringe areas].

Science.gov (United States)

Wan, Fangjun; Xin, Zheng; Zhou, Lin; Bai, Li; Wang, Yongming; Gu, Shaohua; Liu, Shouqin; Li, Mengmeng; Sang, Shaowei; Zhang, Ji; Liu, Qiyong

2014-06-01

To find out the differences in regional characteristics of heat vulnerability between people living in urban centers and urban-fringe areas of Jinan city so as to provide basis for the development of adaptation measures to heat. A cross-sectional survey on heat vulnerability was conducted in urban center and urban-fringe areas of Jinan city, using a self-designed questionnaire among 801 residents at the age of 16 years or older in August 2013. Data of 23 indicators related to heat vulnerability were collected and aggregated to 7 dimensions:health and medical insurance, social networks, heat perception and adaptive behavior, economic status, resources, living environment and working environment. An index score was calculated using a balanced weighted average approach for each dimension, ranging from 0 to 1, with the closer to 1 as greater vulnerability. The scores on heat perception and adaptive behavior, economic status, resources and working environment dimensions for urban-fringe areas were 0.42,0.63,0.55 and 0.62, statistically significantly higher than the urban center area of 0.41,0.51,0.26 and 0.41. Scores of living environment, social networks and health/medical insurance dimensions for urban center area were 0.57,0.49 and 0.31, which were all higher than the urban-fringe areas of 0.50,0.46 and 0.25, with differences statistically significant. Residents living in the urban center might be more vulnerable to heat in terms of living environment, health/medical insurance and social networks while residents living in the urban-fringe areas might more be vulnerable in terms of heat perception and adaptive behavior, economic status, life resources and working environment. These facts indicated that heat vulnerability among residents could be quite different, even at a fine geographic sale. We would thus suggest that intervention strategies on protecting people from heat, should be more targeted.

Flexible Fringe Benefit Plans Save You Money and Keep Employees Happy.

Science.gov (United States)

Johnson, Rob

1987-01-01

This fringe benefit plan saves money for both employers and employees, provides a better fit for employees' actual benefit needs, and allows employees to choose options from a menu of benefits. One option is a flexible spending plan. Employees place a portion of their before-tax income into a special account from which allowable expenses are paid…

Increased interference fringe visibility from the post-fabrication heat treatment of a perfect crystal silicon neutron interferometer

Science.gov (United States)

Heacock, B.; Arif, M.; Cory, D. G.; Gnaeupel-Herold, T.; Haun, R.; Huber, M. G.; Jamer, M. E.; Nsofini, J.; Pushin, D. A.; Sarenac, D.; Taminiau, I.; Young, A. R.

2018-02-01

We find that annealing a previously chemically etched interferometer at 800 °C dramatically increased the interference fringe visibility from 23% to 90%. The Bragg plane misalignments were also measured before and after annealing using neutron rocking curves, showing that Bragg plane alignment was improved across the interferometer after annealing. This suggests that current interferometers with low fringe visibility may be salvageable and that annealing may become an important step in the fabrication process of future neutron interferometers, leading to less need for chemical etching and larger more exotic neutron interferometers.

29 CFR 4.54 - Locality basis of wage and fringe benefit determinations.

Science.gov (United States)

2010-07-01

... pertinent to the employment of particular classes of service employees on the varied kinds of service... of prevailing wage rates and prevailing fringe benefits in all situations under the Act. The locality... area. For example, a survey by the Bureau of Labor Statistics of the Baltimore, Maryland Standard...

Quantization error of CCD cameras and their influence on phase calculation in fringe pattern analysis.

Science.gov (United States)

Skydan, Oleksandr A; Lilley, Francis; Lalor, Michael J; Burton, David R

2003-09-10

We present an investigation into the phase errors that occur in fringe pattern analysis that are caused by quantization effects. When acquisition devices with a limited value of camera bit depth are used, there are a limited number of quantization levels available to record the signal. This may adversely affect the recorded signal and adds a potential source of instrumental error to the measurement system. Quantization effects also determine the accuracy that may be achieved by acquisition devices in a measurement system. We used the Fourier fringe analysis measurement technique. However, the principles can be applied equally well for other phase measuring techniques to yield a phase error distribution that is caused by the camera bit depth.

Rainbow fringes around crevice corrosion formed on stainless steel AISI 316 after ennoblement in seawater

Energy Technology Data Exchange (ETDEWEB)

Wang, W.; Zhang, X. [College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao (China); Wang, J. [College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao (China); State Key Laboratory for Corrosion and Protection, Shenyang (China)

2009-10-15

The crevice corrosion occurrence probability of stainless steel (SS) AISI 316 was increased under ennoblement condition due to chemically added H{sub 2}O{sub 2} into seawater. The H{sub 2}O{sub 2} was used to simulate the important factor causing ennoblement in natural marine biofilm. Morphology of the crevice corrosion was observed using an incident-light source microscopy. Some interesting ''rainbow'' fringes were observed around micro-crevices. The mechanism was discussed from the ions diffusion and potential distribution during the crevice formation. This result shows that under ennoblement condition the colored fringe is a distinct characteristic of the morphology of localized corrosion for stainless steel. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Microwave radiometric aircraft observations of the Fabry-Perot interference fringes of an ice-water system

Science.gov (United States)

Harrington, R. F.; Swift, C. T.; Fedors, J. C.

1980-01-01

Airborne stepped-frequency microwave radiometer (SFMR) observations of the Fabry-Perot interference fringes of ice-water systems are discussed. The microwave emissivity at normal incidence of a smooth layered dielectric medium over a semi-infinite dielectric medium is examined for the case of ice over water as a function of ice thickness and attenuation coefficient, and the presence of quarter-wavelength oscillations in emissivity as the ice thickness and frequency are varied is pointed out. Experimental observations of pronounced quarter-wavelength oscillations in radiometric brightness temperature due to the Fabry-Perot interference fringes over smooth sea ice and lake ice varying in roughness as the radiometer frequencies were scanned are then presented.

2D fringe probing of liquid film dynamics of a plug bubble in a micropipe

International Nuclear Information System (INIS)

Ji, H F; Qiu, H H

2009-01-01

An extended film thickness measurement method that can obtain the liquid film thickness profile of the whole plug bubble in a capillary tube simultaneously is presented. The approach is based on a 2D spatial fringe scattering technique, where the spatial frequency of scattered fringes is a function of liquid film thickness along the micropipe. Laser sheets are used instead of the laser beams, and the width of the laser sheets can be selected to cover the whole measurement field. Capillary tubes, with inner diameters of 1.0 mm and 0.3 mm, and lengths of 125 mm and 65 mm, are used. A gas plug bubble, 2.5–20 mm long, is introduced and moves through the testing part of the tube, which is filled with water as the working fluid. The interference fringes produced by two incident laser sheets are scattered from the interface between gas and water, and captured by a high-speed camera at a speed of up to 2000 frames s −1 . The experimental results show that the improved method can obtain the liquid film thickness profile at the different times and can be used to analyze the status of the plug bubble movement in a micropipe

Pressure-sensitive strain sensor based on a single percolated Ag nanowire layer embedded in colorless polyimide

Energy Technology Data Exchange (ETDEWEB)

Lee, Chan-Jae [Display Materials & Components Research Center, Korea Electronics Technology Institute, 68 Yatap-dong, Bundang-gu, Seongnam 463-816 (Korea, Republic of); Jun, Sungwoo [Display Materials & Components Research Center, Korea Electronics Technology Institute, 68 Yatap-dong, Bundang-gu, Seongnam 463-816 (Korea, Republic of); Display and Nanosystem Laboratory, College of Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Ju, Byeong-Kwon [Display and Nanosystem Laboratory, College of Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Jong-Woong, E-mail: wyjd@keti.re.kr [Display Materials & Components Research Center, Korea Electronics Technology Institute, 68 Yatap-dong, Bundang-gu, Seongnam 463-816 (Korea, Republic of)

2017-06-01

This paper presents the fabrication of an elastomer-free, transparent, pressure-sensitive strain sensor consisting of a specially designed silver nanowire (AgNW) pattern and colorless polyimide (cPI). A percolated AgNW network was patterned with a simple tandem compound circuit, which was then embedded in the surface of the cPI via inverted layer processing. The resulting film-type sensor was highly transparent (~93.5% transmittance at 550 nm) and mechanically stable (capable of resisting 10000 cycles of bending to a 500 µm radius of curvature). We demonstrated that a thin, transparent, and mechanically stable electrode can be produced using a combination of AgNWs and cPI, and used to produce a system sensitive to pressure-induced bending. The capacitance of the AgNW tandem compound electrode pattern grew via fringing, which increased with the pressure-induced bending applied to the surface of the sensor. The sensitivity was four times higher than that of an elastomeric pressure sensor made with the same design. Finally, we demonstrated a skin-like pressure sensor attached to the inside wrist of a human arm. - Highlights: • A thin, transparent pressure sensor was fabricated from AgNWs and cPI. • An AgNW network was patterned with a simple circuit, and then embedded into cPI. • The resulting film-type sensor was highly transparent and mechanically stable. • The sensor sensitivity was 4x higher than that of an elastomeric pressure sensor.

Location choice of Chinese urban fringe residents on employment, housing, and urban services: A case study of Nanjing

Directory of Open Access Journals (Sweden)

Xingping Wang

2016-03-01

Full Text Available Urban fringe area is the most important space for city development. It includes several complicated elements, such as population, space, and management organization. On the basis of local population attributes in the city fringe area combined with people’s movement characteristics in time and space, this article reclassifies basic public service facilities and discusses the relationship between facility layout and housing, employment, and commuter transportation. Through a questionnaire survey in Qiaobei District of the urban fringe area in Nanjing and on the basis of comparative analysis, we discuss the impact factor on the choice of housing, urban services, and the tolerance of commuting time. Our findings indicate mutual promoting and restricting connections among living, employment, and services. Workers’ living situation determines their daily behavior, such as dining, shopping, and entertainment. Furthermore, different income levels have a great influence on residents’ choices with regard to places to live and develop their careers.

Design considerations in projection phase-shift moiré topography based on theoretical analysis of fringe formation.

Science.gov (United States)

Buytaert, Jan A N; Dirckx, Joris J J

2007-07-01

Moiré topography is a well-established optical technique to measure the shape of three-dimensional surfaces, based on the geometric interference between an optical grid and its image deformed by an object surface. The technique produces fringes that represent contours of equal height, and from the recordings of several phase-shifted topograms surface height coordinates can be calculated. To perform these calculations, it is assumed that object height variation is small in comparison with the measurement setup dimensions, and this approximation leads to systematic errors in measurement accuracy. We present the mathematical description of the fringe formation process in projection moiré topography, and on the basis of these equations we establish the relation between setup geometry and upper limits of the systematic measurement errors. We derive the equations that determine design specifications needed to reduce the effects of approximations to be below the measurement resolution of the setup. It is shown that setup geometry should be adapted to the gray-scale measurement resolution of the imaging system. We show that, using an iterative correction from one fringe order to the next, measurement accuracy can be maintained over the entire object depth.

Highly sensitive magnetic field sensor based on microfiber coupler with magnetic fluid

International Nuclear Information System (INIS)

Luo, Longfeng; Pu, Shengli; Tang, Jiali; Zeng, Xianglong; Lahoubi, Mahieddine

2015-01-01

A kind of magnetic field sensor using a microfiber coupler (MFC) surrounded with magnetic fluid (MF) is proposed and experimentally demonstrated. As the MFC is strongly sensitive to the surrounding refractive index (RI) and MF's RI is sensitive to magnetic field, the magnetic field sensing function of the proposed structure is realized. Interrogation of magnetic field strength is achieved by measuring the dip wavelength shift and transmission loss change of the transmission spectrum. The experimental results show that the sensitivity of the sensor is wavelength-dependent. The maximum sensitivity of 191.8 pm/Oe is achieved at wavelength of around 1537 nm in this work. In addition, a sensitivity of −0.037 dB/Oe is achieved by monitoring variation of the fringe visibility. These suggest the potential applications of the proposed structure in tunable all-in-fiber photonic devices such as magneto-optical modulator, filter, and sensing

Highly sensitive magnetic field sensor based on microfiber coupler with magnetic fluid

Energy Technology Data Exchange (ETDEWEB)

Luo, Longfeng; Pu, Shengli, E-mail: shlpu@usst.edu.cn; Tang, Jiali [College of Science, University of Shanghai for Science and Technology, Shanghai 200093 (China); Zeng, Xianglong [2Key Laboratory of Specialty Fiber Optics and Optical Access Network, Shanghai University, Shanghai 200072 (China); Lahoubi, Mahieddine [Department of Physics, Faculty of Sciences, Laboratory L.P.S., Badji Mokhtar-Annaba University, P. O. Box 12, 23000 Annaba (Algeria)

2015-05-11

A kind of magnetic field sensor using a microfiber coupler (MFC) surrounded with magnetic fluid (MF) is proposed and experimentally demonstrated. As the MFC is strongly sensitive to the surrounding refractive index (RI) and MF's RI is sensitive to magnetic field, the magnetic field sensing function of the proposed structure is realized. Interrogation of magnetic field strength is achieved by measuring the dip wavelength shift and transmission loss change of the transmission spectrum. The experimental results show that the sensitivity of the sensor is wavelength-dependent. The maximum sensitivity of 191.8 pm/Oe is achieved at wavelength of around 1537 nm in this work. In addition, a sensitivity of −0.037 dB/Oe is achieved by monitoring variation of the fringe visibility. These suggest the potential applications of the proposed structure in tunable all-in-fiber photonic devices such as magneto-optical modulator, filter, and sensing.

Micro-structured optical fiber sensor for simultaneous measurement of temperature and refractive index

Science.gov (United States)

Liu, Ying-gang; Liu, Xin; Ma, Cheng-ju; Zhou, Yu-min

2018-03-01

Through using micro-machining method for optical fiber sensor, a kind of miniature, compact and composite structural all-fiber sensor is presented. Based on manufacturing two micro-holes with certain distance in ordinary single-mode fiber Bragg grating (FBG) by excimer laser processing technique, we fabricate a dual Fabry-Perot-FBG (FP-FBG) composite fiber interferometric sensor, which can be used in simultaneous measurement for liquid's refractive index (RI) and temperature change. Due to every micro-hole and the dual micro-holes in fiber acting as different Fabry-Perot (FP) cavities, this kind of sensor has not only different RI sensitivities but also different temperature sensitivities, which are corresponding to the wavelength shifts of the fine interference fringes and spectral envelope, respectively. The experimental results show that the spectral wavelength shift keep better linear response for temperature and RI change, so that we can select the higher temperature and RI sensitivities as well as the analyzed sensitivities of FBG to utilize them for constituting a sensitivity coefficients matrix. Finally, the variations of liquid's temperature and RI are detected effectively, and the resolutions can reach to 0.1 °C and 1.0 ×10-5 RIU. These characteristics are what other single-type sensors don't have, so that this kind of all-fiber dual FP-FBG composite fiber interferometric sensor can be used in extremely tiny liquid environment for measuring different physical quantities simultaneously.

Electrocatalytic glucose sensor

Energy Technology Data Exchange (ETDEWEB)

Gebhardt, U; Luft, G; Mund, K; Preidel, W; Richter, G J

1983-01-01

An artificial pancreas consists of an insulin depot, a dosage unit and a glucose sensor. The measurement of the actual glucose concentration in blood is still an unsolved problem. Two methods are described for an electrocatalytic glucose sensor. Under the interfering action of amino acids and urea in-vitro measurements show an error of between 10% and 20%.

Proximity Operations and Docking Sensor Development

Science.gov (United States)

Howard, Richard T.; Bryan, Thomas C.; Brewster, Linda L.; Lee, James E.

2009-01-01

The Next Generation Advanced Video Guidance Sensor (NGAVGS) has been under development for the last three years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in spot mode out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. 12 Parts obsolescence issues prevent the construction of more AVGS units, and the next generation sensor was updated to allow it to support the CEV and COTS programs. The flight proven AR&D sensor has been redesigned to update parts and add additional capabilities for CEV and COTS with the development of the Next Generation AVGS at the Marshall Space Flight Center. The obsolete imager and processor are being replaced with new radiation tolerant parts. In addition, new capabilities include greater sensor range, auto ranging capability, and real-time video output. This paper presents some sensor hardware trades, use of highly integrated laser components, and addresses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It also discusses approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements

Underwater 3D Surface Measurement Using Fringe Projection Based Scanning Devices.

Science.gov (United States)

Bräuer-Burchardt, Christian; Heinze, Matthias; Schmidt, Ingo; Kühmstedt, Peter; Notni, Gunther

2015-12-23

In this work we show the principle of optical 3D surface measurements based on the fringe projection technique for underwater applications. The challenges of underwater use of this technique are shown and discussed in comparison with the classical application. We describe an extended camera model which takes refraction effects into account as well as a proposal of an effective, low-effort calibration procedure for underwater optical stereo scanners. This calibration technique combines a classical air calibration based on the pinhole model with ray-based modeling and requires only a few underwater recordings of an object of known length and a planar surface. We demonstrate a new underwater 3D scanning device based on the fringe projection technique. It has a weight of about 10 kg and the maximal water depth for application of the scanner is 40 m. It covers an underwater measurement volume of 250 mm × 200 mm × 120 mm. The surface of the measurement objects is captured with a lateral resolution of 150 μm in a third of a second. Calibration evaluation results are presented and examples of first underwater measurements are given.

Smart Rocking Armour Units

NARCIS (Netherlands)

Hofland, B.; Arefin, Syed Shamsil; van der Lem, Cock; van gent, Marcel

2018-01-01

This paper describes a method to measure the rocking motion of lab-scale armour units. Sensors as found in mobile phones are used. These sensors, data-storage and battery are all embedded in the model units, such that they can be applied without wires attached to them. The technique is applied to

A general theory of interference fringes in x-ray phase grating imaging

International Nuclear Information System (INIS)

Yan, Aimin; Wu, Xizeng; Liu, Hong

2015-01-01

Purpose: The authors note that the concept of the Talbot self-image distance in x-ray phase grating interferometry is indeed not well defined for polychromatic x-rays, because both the grating phase shift and the fractional Talbot distances are all x-ray wavelength-dependent. For x-ray interferometry optimization, there is a need for a quantitative theory that is able to predict if a good intensity modulation is attainable at a given grating-to-detector distance. In this work, the authors set out to meet this need. Methods: In order to apply Fourier analysis directly to the intensity fringe patterns of two-dimensional and one-dimensional phase grating interferometers, the authors start their derivation from a general phase space theory of x-ray phase-contrast imaging. Unlike previous Fourier analyses, the authors evolved the Wigner distribution to obtain closed-form expressions of the Fourier coefficients of the intensity fringes for any grating-to-detector distance, even if it is not a fractional Talbot distance. Results: The developed theory determines the visibility of any diffraction order as a function of the grating-to-detector distance, the phase shift of the grating, and the x-ray spectrum. The authors demonstrate that the visibilities of diffraction orders can serve as the indicators of the underlying interference intensity modulation. Applying the theory to the conventional and inverse geometry configurations of single-grating interferometers, the authors demonstrated that the proposed theory provides a quantitative tool for the grating interferometer optimization with or without the Talbot-distance constraints. Conclusions: In this work, the authors developed a novel theory of the interference intensity fringes in phase grating x-ray interferometry. This theory provides a quantitative tool in design optimization of phase grating x-ray interferometers

A general theory of interference fringes in x-ray phase grating imaging.

Science.gov (United States)

Yan, Aimin; Wu, Xizeng; Liu, Hong

2015-06-01

The authors note that the concept of the Talbot self-image distance in x-ray phase grating interferometry is indeed not well defined for polychromatic x-rays, because both the grating phase shift and the fractional Talbot distances are all x-ray wavelength-dependent. For x-ray interferometry optimization, there is a need for a quantitative theory that is able to predict if a good intensity modulation is attainable at a given grating-to-detector distance. In this work, the authors set out to meet this need. In order to apply Fourier analysis directly to the intensity fringe patterns of two-dimensional and one-dimensional phase grating interferometers, the authors start their derivation from a general phase space theory of x-ray phase-contrast imaging. Unlike previous Fourier analyses, the authors evolved the Wigner distribution to obtain closed-form expressions of the Fourier coefficients of the intensity fringes for any grating-to-detector distance, even if it is not a fractional Talbot distance. The developed theory determines the visibility of any diffraction order as a function of the grating-to-detector distance, the phase shift of the grating, and the x-ray spectrum. The authors demonstrate that the visibilities of diffraction orders can serve as the indicators of the underlying interference intensity modulation. Applying the theory to the conventional and inverse geometry configurations of single-grating interferometers, the authors demonstrated that the proposed theory provides a quantitative tool for the grating interferometer optimization with or without the Talbot-distance constraints. In this work, the authors developed a novel theory of the interference intensity fringes in phase grating x-ray interferometry. This theory provides a quantitative tool in design optimization of phase grating x-ray interferometers.

Water level effects on breaking wave setup for Pacific Island fringing reefs

Science.gov (United States)

Becker, J. M.; Merrifield, M. A.; Ford, M.

2014-02-01

The effects of water level variations on breaking wave setup over fringing reefs are assessed using field measurements obtained at three study sites in the Republic of the Marshall Islands and the Mariana Islands in the western tropical Pacific Ocean. At each site, reef flat setup varies over the tidal range with weaker setup at high tide and stronger setup at low tide for a given incident wave height. The observed water level dependence is interpreted in the context of radiation stress gradients specified by an idealized point break model generalized for nonnormally incident waves. The tidally varying setup is due in part to depth-limited wave heights on the reef flat, as anticipated from previous reef studies, but also to tidally dependent breaking on the reef face. The tidal dependence of the breaking is interpreted in the context of the point break model in terms of a tidally varying wave height to water depth ratio at breaking. Implications for predictions of wave-driven setup at reef-fringed island shorelines are discussed.

Unsaturated flow characterization utilizing water content data collected within the capillary fringe

Science.gov (United States)

Baehr, Arthur; Reilly, Timothy J.

2014-01-01

An analysis is presented to determine unsaturated zone hydraulic parameters based on detailed water content profiles, which can be readily acquired during hydrological investigations. Core samples taken through the unsaturated zone allow for the acquisition of gravimetrically determined water content data as a function of elevation at 3 inch intervals. This dense spacing of data provides several measurements of the water content within the capillary fringe, which are utilized to determine capillary pressure function parameters via least-squares calibration. The water content data collected above the capillary fringe are used to calculate dimensionless flow as a function of elevation providing a snapshot characterization of flow through the unsaturated zone. The water content at a flow stagnation point provides an in situ estimate of specific yield. In situ determinations of capillary pressure function parameters utilizing this method, together with particle-size distributions, can provide a valuable supplement to data libraries of unsaturated zone hydraulic parameters. The method is illustrated using data collected from plots within an agricultural research facility in Wisconsin.

29 CFR 4.5 - Contract specification of determined minimum wages and fringe benefits.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Contract specification of determined minimum wages and... of determined minimum wages and fringe benefits. (a) Any contract in excess of $2,500 shall contain, as an attachment, the applicable, currently effective wage determination specifying the minimum wages...

Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe.

Science.gov (United States)

Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H

2015-12-01

Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp=200...600 μm, porosity ε=0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol)=0 after t=6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest. Copyright © 2015 Elsevier B.V. All rights

Novel motor design for rotating anode x-ray tubes operating in the fringe field of a magnetic resonance imaging system.

Science.gov (United States)

Lillaney, Prasheel; Shin, Mihye; Hinshaw, Waldo; Bennett, N Robert; Pelc, Norbert; Fahrig, Rebecca

2013-02-01

Using hybrid x-ray∕MR (XMR) systems for image guidance during interventional procedures could enhance the diagnosis and treatment of neurologic, oncologic, cardiovascular, and other disorders. The authors propose a close proximity hybrid system design in which a C-arm fluoroscopy unit is placed immediately adjacent to the solenoid magnet of a MR system with a minimum distance of 1.2 m between the x-ray and MR imaging fields of view. Existing rotating anode x-ray tube designs fail within MR fringe field environments because the magnetic fields alter the electron trajectories in the x-ray tube and act as a brake on the induction motor, reducing the rotation speed of the anode. In this study the authors propose a novel motor design that avoids the anode rotation speed reduction. The proposed design replaces the permanent magnet stator found in brushed dc motors with the radial component of the MR fringe field. The x-ray tube is oriented such that the radial component of the MR fringe field is orthogonal to the cathode-anode axis. Using a feedback position sensor and the support bearings as electrical slip rings, the authors use electrical commutation to eliminate the need for mechanical brushes and commutators. A vacuum compatible prototype of the proposed motor design was assembled, and its performance was evaluated at various operating conditions. The prototype consisted of a 3.1 in. diameter anode rated at 300 kHU with a ceramic rotor that was 5.6 in. in length and had a 2.9 in. diameter. The material chosen for all ceramic components was MACOR, a machineable glass ceramic developed by Corning Inc. The approximate weight of the entire assembly was 1750 g. The maximum rotation speed, angular acceleration, and acceleration time of the motor design were investigated, as well as the dependence of these parameters on rotor angular offset, magnetic field strength, and field orientation. The resonance properties of the authors' assembly were also evaluated to determine

Novel motor design for rotating anode x-ray tubes operating in the fringe field of a magnetic resonance imaging system

Energy Technology Data Exchange (ETDEWEB)

Lillaney, Prasheel; Pelc, Norbert [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States); Shin Mihye [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Hinshaw, Waldo; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Bennett, N. Robert [Department of Radiology, Stanford University, Stanford, California 94305 and Qualcomm MEMS Technologies, San Jose, California 95134 (United States)

2013-02-15

Purpose: Using hybrid x-ray/MR (XMR) systems for image guidance during interventional procedures could enhance the diagnosis and treatment of neurologic, oncologic, cardiovascular, and other disorders. The authors propose a close proximity hybrid system design in which a C-arm fluoroscopy unit is placed immediately adjacent to the solenoid magnet of a MR system with a minimum distance of 1.2 m between the x-ray and MR imaging fields of view. Existing rotating anode x-ray tube designs fail within MR fringe field environments because the magnetic fields alter the electron trajectories in the x-ray tube and act as a brake on the induction motor, reducing the rotation speed of the anode. In this study the authors propose a novel motor design that avoids the anode rotation speed reduction. Methods: The proposed design replaces the permanent magnet stator found in brushed dc motors with the radial component of the MR fringe field. The x-ray tube is oriented such that the radial component of the MR fringe field is orthogonal to the cathode-anode axis. Using a feedback position sensor and the support bearings as electrical slip rings, the authors use electrical commutation to eliminate the need for mechanical brushes and commutators. A vacuum compatible prototype of the proposed motor design was assembled, and its performance was evaluated at various operating conditions. The prototype consisted of a 3.1 in. diameter anode rated at 300 kHU with a ceramic rotor that was 5.6 in. in length and had a 2.9 in. diameter. The material chosen for all ceramic components was MACOR, a machineable glass ceramic developed by Corning Inc. The approximate weight of the entire assembly was 1750 g. The maximum rotation speed, angular acceleration, and acceleration time of the motor design were investigated, as well as the dependence of these parameters on rotor angular offset, magnetic field strength, and field orientation. The resonance properties of the authors' assembly were also

Multiple rotation assessment through isothetic fringes in speckle photography

International Nuclear Information System (INIS)

Angel, Luciano; Tebaldi, Myrian; Bolognini, Nestor

2007-01-01

The use of different pupils for storing each speckled image in speckle photography is employed to determine multiple in-plane rotations. The method consists of recording a four-exposure specklegram where the rotations are done between exposures. This specklegram is then optically processed in a whole field approach rendering isothetic fringes, which give detailed information about the multiple rotations. It is experimentally demonstrated that the proposed arrangement permits the depiction of six isothetics in order to measure either six different angles or three nonparallel components for two local general in-plane displacements

Color Fringes Bordering Black Stripes at the Bottom of a Swimming Pool

Science.gov (United States)

Fuster, Gonzalo; Rojas, Roberto; Slüsarenko, Viktor

2016-01-01

We have observed a nice example of chromatic dispersion due to refraction in water, in the form of color fringes bordering the black stripes that exist at the bottom of a swimming pool. Here we give a qualitative description of the phenomenon, explaining the role of the black stripes and the dispersive index of refraction of water.

Experimental and Numerical Studies on Wave Breaking Characteristics over a Fringing Reef under Monochromatic Wave Conditions

Directory of Open Access Journals (Sweden)

Jong-In Lee

2014-01-01

Full Text Available Fringing reefs play an important role in protecting the coastal area by inducing wave breaking and wave energy dissipation. However, modeling of wave transformation and energy dissipation on this topography is still difficult due to the unique structure. In the present study, two-dimensional laboratory experiments were conducted to investigate the cross-shore variations of wave transformation, setup, and breaking phenomena over an idealized fringing reef with the 1/40 reef slope and to verify the Boussinesq model under monochromatic wave conditions. One-layer and two-layer model configurations of the Boussinesq model were used to figure out the model capability. Both models predicted well (r2>0.8 the cross-shore variation of the wave heights, crests, troughs, and setups when the nonlinearity is not too high (A0/h0<0.07 in this study. However, as the wave nonlinearity and steepness increase, the one-layer model showed problems in prediction and stability due to the error on the vertical profile of fluid velocity. The results in this study revealed that one-layer model is not suitable in the highly nonlinear wave condition over a fringing reef bathymetry. This data set can contribute to the numerical model verification.

Cost-effective optical fiber pressure sensor based on intrinsic Fabry-Perot interferometric micro-cavities

Science.gov (United States)

Domingues, M. Fátima; Rodriguez, Camilo A.; Martins, Joana; Tavares, Cátia; Marques, Carlos; Alberto, Nélia; André, Paulo; Antunes, Paulo

2018-05-01

In this work, a cost-effective procedure to manufacture optical fiber pressure sensors is presented. This has a high relevance for integration in robotic exoskeletons or for gait plantar pressure monitoring within the physical rehabilitation scenarios, among other applications. The sensing elements are based on Fabry-Perot interferometric (FPI) micro-cavities, created from the recycling of optical fibers previously destroyed by the catastrophic fuse effect. To produce the pressure sensors, the fiber containing the FPI micro-cavities was embedded in an epoxy resin cylinder used as pressure transducer and responsible to transfer the pressure applied on its surface to the optical fiber containing the FPI micro-cavity. Before the embedding process, some FPI sensors were also characterized to strain variations. After that, the effect of the encapsulation of the FPI structure into the resin was assessed, from which a slight decrease on the FPI interferogram fringes visibility was verified, indicating a small increase in the micro-cavity length. Up on the sensors characterization, a linear dependence of the wavelength shift with the induced pressure was obtained, which leads to a maximum sensitivity of 59.39 ± 1.7 pm/kPa. Moreover, direct dependence of the pressure sensitivity with the micro-cavity volume and length was found.

VLTI First Fringes with Two Auxiliary Telescopes at Paranal

Science.gov (United States)

2005-03-01

interferometric installation of this size and crucial for its exceptional performance. The ATs may be placed at 30 different positions and thus be combined in a very large number of ways. If the 8.2-m VLT Unit Telescopes are also taken into account, no less than 254 independent pairings of two telescopes ("baselines"), different in length and/or orientation, are available. Moreover, while the largest possible distance between two 8.2-m telescopes (ANTU and YEPUN) is about 130 metres, the maximal distance between two ATs may reach 200 metres. As the achievable image sharpness increases with telescope separation, interferometric observations with the ATs positioned at the extreme positions will therefore yield sharper images than is possible by combining light from the large telescopes alone. All of this will enable the VLTI to obtain exceedingly detailed (sharp) and very complete images of celestial objects - ultimately with a resolution that corresponds to detecting an astronaut on the Moon. Auxiliary Telescope no. 1 (AT1) was installed on the observatory's platform in January 2004. Now, one year later, the second of the four to be delivered, has been integrated into the VLTI. The installation period lasted two months and ended around midnight during the night of February 2-3, 2005. With extensive experience from the installation of AT1, the team of engineers and astronomers were able to combine the light from the two Auxiliary Telescopes in a very short time. In fact, following the necessary preparations, it took them only five minutes to adjust this extremely complex optical system and successfully capture the "First Fringes" with the VINCI test instrument! The star which was observed is named HD62082 and is just at the limit of what can be observed with the unaided eye (its visual magnitude is 6.2). The fringes were as clear as ever, and the VLTI control system kept them stable for more than one hour. Four nights later this exercise was repeated successfully with the mid

High-precision angle sensor based on a Köster’s prism with absolute zero-point

Science.gov (United States)

Ullmann, V.; Oertel, E.; Manske, E.

2018-06-01

In this publication, a novel approach will be presented to use a compact white-light interferometer based on a Köster’s prism for angle measurements. Experiments show that the resolution of this angle interferometer is in the range of a commercial digital autocollimator, with a focal length of f  =  300 mm, but with clearly reduced signal noise and without overshoot artifacts in the signal caused by digital filters. The angle detection of the reference mirror in the Köster’s interferometer is based on analysing the rotation angle of the fringe pattern, which is projected on a CMOS-matrix. The fringe pattern is generated by two displaced spherical wave fronts coming from one fiber-coupled white-light source and getting divided into a reference and a measurement beam by the Köster’s prism. The displacement correlates with the reference angle mirror in one linear direction and with the angle aberrations of the prism in the other orthogonal direction on the CMOS sensor. We will present the experimental and optical setup, the method and algorithms for the image-to-angle processing as well as the experimental results obtained in calibration and long-term measurements.

The Mass1frings mutation underlies early onset hearing impairment in BUB/BnJ mice, a model for the auditory pathology of Usher syndrome IIC

Science.gov (United States)

Johnson, K.R.; Zheng, Q.Y.; Weston, M.D.; Ptacek, L.J.; Noben-Trauth, K.

2010-01-01

The human ortholog of the gene responsible for audiogenic seizure susceptibility in Frings and BUB/BnJ mice (mouse gene symbol Mass1) recently was shown to underlie Usher syndrome type IIC (USH2C). Here we report that the Mass1frings mutation is responsible for the early onset hearing impairment of BUB/BnJ mice. We found highly significant linkage of Mass1 with ABR threshold variation among mice from two backcrosses involving BUB/BnJ mice with mice of strains CAST/EiJ and MOLD/RkJ. We also show an additive effect of the Cdh23 locus in modulating the progression of hearing loss in backcross mice. Together, these two loci account for more than 70% of the total ABR threshold variation among the backcross mice at all ages. The modifying effect of the strain-specific Cdh23ahl variant may account for the hearing and audiogenic seizure differences observed between Frings and BUB/BnJ mice, which share the Mass1frings mutation. During postnatal cochlear development in BUB/BnJ mice, stereocilia bundles develop abnormally and remain immature and splayed into adulthood, corresponding with the early onset hearing impairment associated with Mass1frings. Progressive base–apex hair cell degeneration occurs at older ages, corresponding with the age-related hearing loss associated with Cdh23ahl. The molecular basis and pathophysiology of hearing loss suggest BUB/BnJ and Frings mice as models to study cellular and molecular mechanisms underlying USH2C auditory pathology. PMID:15820310

Extrinsic fiber-optic Fabry-Perot interferometer sensor for refractive index measurement of optical glass

International Nuclear Information System (INIS)

Chen Jihuan; Zhao Jiarong; Huang Xuguang; Huang Zhenjian

2010-01-01

A simple fiber-optic sensor based on Fabry-Perot interference for refractive index measurement of optical glass is investigated both theoretically and experimentally. A broadband light source is coupled into an extrinsic fiber Fabry-Perot cavity formed by the surfaces of a sensing fiber end and the measured sample. The interference signals from the cavity are reflected back into the same fiber. The refractive index of the sample can be obtained by measuring the contrast of the interference fringes. The experimental data meet with the theoretical values very well. The proposed technique is a new method for glass refractive index measurement with a simple, solid, and compact structure.

Compact, low-cost, and high-resolution interrogation unit for optical sensors

International Nuclear Information System (INIS)

Kiesel, Peter; Schmidt, Oliver; Mohta, Setu; Johnson, Noble; Malzer, Stefan

2006-01-01

Compact wavelength detectors that resolve wavelength changes in the subpicometer range over a broad spectral range are presented. A photodiode array or position sensor device is coated with a linear variable filter that converts the wavelength of the incident light into a spatial intensity distribution. The centroid of the spatial distribution is determined by a differential readout of the two elements of the photodiode array or the position sensor device. The device can interrogate any optical sensor that produces a wavelength shift in response to a stimulus. The potential of this device was tested by interrogating fiber-Bragg-grating sensors

Phase accuracy evaluation for phase-shifting fringe projection profilometry based on uniform-phase coded image

Science.gov (United States)

Zhang, Chunwei; Zhao, Hong; Zhu, Qian; Zhou, Changquan; Qiao, Jiacheng; Zhang, Lu

2018-06-01

Phase-shifting fringe projection profilometry (PSFPP) is a three-dimensional (3D) measurement technique widely adopted in industry measurement. It recovers the 3D profile of measured objects with the aid of the fringe phase. The phase accuracy is among the dominant factors that determine the 3D measurement accuracy. Evaluation of the phase accuracy helps refine adjustable measurement parameters, contributes to evaluating the 3D measurement accuracy, and facilitates improvement of the measurement accuracy. Although PSFPP has been deeply researched, an effective, easy-to-use phase accuracy evaluation method remains to be explored. In this paper, methods based on the uniform-phase coded image (UCI) are presented to accomplish phase accuracy evaluation for PSFPP. These methods work on the principle that the phase value of a UCI can be manually set to be any value, and once the phase value of a UCI pixel is the same as that of a pixel of a corresponding sinusoidal fringe pattern, their phase accuracy values are approximate. The proposed methods provide feasible approaches to evaluating the phase accuracy for PSFPP. Furthermore, they can be used to experimentally research the property of the random and gamma phase errors in PSFPP without the aid of a mathematical model to express random phase error or a large-step phase-shifting algorithm. In this paper, some novel and interesting phenomena are experimentally uncovered with the aid of the proposed methods.

Improvement of the fringe analysis algorithm for wavelength scanning interferometry based on filter parameter optimization.

Science.gov (United States)

Zhang, Tao; Gao, Feng; Muhamedsalih, Hussam; Lou, Shan; Martin, Haydn; Jiang, Xiangqian

2018-03-20

The phase slope method which estimates height through fringe pattern frequency and the algorithm which estimates height through the fringe phase are the fringe analysis algorithms widely used in interferometry. Generally they both extract the phase information by filtering the signal in frequency domain after Fourier transform. Among the numerous papers in the literature about these algorithms, it is found that the design of the filter, which plays an important role, has never been discussed in detail. This paper focuses on the filter design in these algorithms for wavelength scanning interferometry (WSI), trying to optimize the parameters to acquire the optimal results. The spectral characteristics of the interference signal are analyzed first. The effective signal is found to be narrow-band (near single frequency), and the central frequency is calculated theoretically. Therefore, the position of the filter pass-band is determined. The width of the filter window is optimized with the simulation to balance the elimination of the noise and the ringing of the filter. Experimental validation of the approach is provided, and the results agree very well with the simulation. The experiment shows that accuracy can be improved by optimizing the filter design, especially when the signal quality, i.e., the signal noise ratio (SNR), is low. The proposed method also shows the potential of improving the immunity to the environmental noise by adapting the signal to acquire the optimal results through designing an adaptive filter once the signal SNR can be estimated accurately.

Fringe pattern demodulation using the one-dimensional continuous wavelet transform: field-programmable gate array implementation.

Science.gov (United States)

Abid, Abdulbasit

2013-03-01

This paper presents a thorough discussion of the proposed field-programmable gate array (FPGA) implementation for fringe pattern demodulation using the one-dimensional continuous wavelet transform (1D-CWT) algorithm. This algorithm is also known as wavelet transform profilometry. Initially, the 1D-CWT is programmed using the C programming language and compiled into VHDL using the ImpulseC tool. This VHDL code is implemented on the Altera Cyclone IV GX EP4CGX150DF31C7 FPGA. A fringe pattern image with a size of 512×512 pixels is presented to the FPGA, which processes the image using the 1D-CWT algorithm. The FPGA requires approximately 100 ms to process the image and produce a wrapped phase map. For performance comparison purposes, the 1D-CWT algorithm is programmed using the C language. The C code is then compiled using the Intel compiler version 13.0. The compiled code is run on a Dell Precision state-of-the-art workstation. The time required to process the fringe pattern image is approximately 1 s. In order to further reduce the execution time, the 1D-CWT is reprogramed using Intel Integrated Primitive Performance (IPP) Library Version 7.1. The execution time was reduced to approximately 650 ms. This confirms that at least sixfold speedup was gained using FPGA implementation over a state-of-the-art workstation that executes heavily optimized implementation of the 1D-CWT algorithm.

Smart Rocking Armour Units

OpenAIRE

Hofland, B.; Arefin, Syed Shamsil; van der Lem, Cock; van gent, Marcel

2018-01-01

This paper describes a method to measure the rocking motion of lab-scale armour units. Sensors as found in mobile phones are used. These sensors, data-storage and battery are all embedded in the model units, such that they can be applied without wires attached to them. The technique is applied to double-layer units in order to compare the results to the existing knowledge for this type of armour layers. In contrast to previous research, the gyroscope reading is used to determine the (rocking)...

Urodynamic pressure sensor

Science.gov (United States)

Moore, Thomas

1991-01-01

A transducer system was developed for measuring the closing pressure profile along the female urethra, which provides up to five sensors within the functional length of the urethra. This new development is an improvement over an earlier measurement method that has a smaller sensor area and was unable to respond to transient events. Three sensors were constructed; one of them was subjected to approximately eight hours of use in a clinical setting during which 576 data points were obtained. The complete instrument system, including the signal conditioning electronics, data acquisition unit, and the computer with its display and printer is described and illustrated.

Digital fringe projection for hand surface coordinate variation analysis caused by osteoarthritis

Science.gov (United States)

Nor Haimi, Wan Mokhdzani Wan; Hau Tan, Cheek; Retnasamy, Vithyacharan; Vairavan, Rajendaran; Sauli, Zaliman; Roshidah Yusof, Nor; Hambali, Nor Azura Malini Ahmad; Aziz, Muhammad Hafiz Ab; Bakhit, Ahmad Syahir Ahmad

2017-11-01

Hand osteoarthritis is one of the most common forms of arthritis which impact millions of people worldwide. The disabling problem occurs when the protective cartilage on the boundaries of bones wear off over time. Currently, in order to identify hand osteoarthritis, special instruments namely X-ray scanning and MRI are used for the detection but it also has its limitations such as radiation exposure and can be quite costly. In this work, an optical metrology system based on digital fringe projection which comprises of an LCD projector, CCD camera and a personal computer has been developed to anticipate abnormal growth or deformation on the joints of the hand which are common symptoms of osteoarthritis. The main concept of this optical metrology system is to apply structured light as imaging source for surface change detection. The imaging source utilizes fringe patterns generated by C++ programming and is shifted by 3 phase shifts based on the 3 steps 2 shifts method. Phase wrapping technique and analysis were applied in order to detect the deformation of live subjects. The result has demonstrated a successful method of hand deformation detection based on the pixel tracking differences of a normal and deformed state.

Clock-Frequency Switching Technique for Energy Saving of Microcontroller Unit (MCU-Based Sensor Node

Directory of Open Access Journals (Sweden)

Pumin Duangmanee

2018-05-01

Full Text Available In this paper; a technique is proposed for reducing the energy consumption of microcontroller-based sensor nodes by switching the operating clock between low and high frequencies. The proposed concept is motivated by the fact that if the application codes of the microcontroller unit (MCU consist of no-wait state instruction sets, it consumes less energy when it operates with a higher frequency. When the application code of the MCU consists of wait instruction sets; e.g., a wait acknowledge signal, it switches to low clock frequency. The experimental results confirm that the proposed technique can reduce the MCU energy consumption up to 66.9%.

IN SITU ABIOTIC DETOXIFICATION AND IMMOBILIZATION OF HEXAVALENT CHROMIUM IN THE CAPILLARY FRINGE ZONE

Science.gov (United States)

Detailed site characterization data from the former electroplating shop at the U.S. Coast Guard Air Support Center, Elizabeth City, North Carolina suggested that the elevated Cr(VI) in the capillary fringe area had contaminated the ground water at the site. Most of the mobile Cr(...

Correlative studies of satellite ozone sensor measurements

International Nuclear Information System (INIS)

Lovill, J.E.; Ellis, J.S.

1983-01-01

Comparisons are made between total ozone measurements made by four satellite ozone sensors (TOMS, SBUV, TOVS and MFR). The comparisons were made during July 1979 when all sensors were operating simultaneously. The TOMS and SBUV sensors were observed to measure less total ozone than the MFR sensor, 10 and 15 Dobson units (DU) respectively. The MFR and TOMS sensors measured less ozone than the TOVS sensor, 19 an 28 DU, respectively. Latitudinal variability of the total ozone comparisons is discussed

Wireless Biological Electronic Sensors.

Science.gov (United States)

Cui, Yue

2017-10-09

The development of wireless biological electronic sensors could open up significant advances for both fundamental studies and practical applications in a variety of areas, including medical diagnosis, environmental monitoring, and defense applications. One of the major challenges in the development of wireless bioelectronic sensors is the successful integration of biosensing units and wireless signal transducers. In recent years, there are a few types of wireless communication systems that have been integrated with biosensing systems to construct wireless bioelectronic sensors. To successfully construct wireless biological electronic sensors, there are several interesting questions: What types of biosensing transducers can be used in wireless bioelectronic sensors? What types of wireless systems can be integrated with biosensing transducers to construct wireless bioelectronic sensors? How are the electrical sensing signals generated and transmitted? This review will highlight the early attempts to address these questions in the development of wireless biological electronic sensors.

Optical detection system for MEMS-type pressure sensor

International Nuclear Information System (INIS)

Sareło, K; Górecka-Drzazga, A; Dziuban, J A

2015-01-01

In this paper a special optical detection system designed for a MEMS-type (micro-electro-mechanical system) silicon pressure sensor is presented. The main part of the optical system—a detection unit with a perforated membrane—is bonded to the silicon sensor, and placed in a measuring system. An external light source illuminates the membrane of the pressure sensor. Owing to the light reflected from the deflected membrane sensor, the optical pattern consisting of light points is visible, and pressure can be estimated. The optical detection unit (20   ×   20   ×   20.4 mm 3 ) is fabricated using microengineering techniques. Its dimensions are adjusted to the dimensions of the pressure sensor (5   ×   5 mm 2 silicon membrane). Preliminary tests of the optical detection unit integrated with the silicon pressure sensor are carried out. For the membrane sensor from 15 to 60 µm thick, a repeatable detection of the differential pressure in the range of 0 to 280 kPa is achieved. The presented optical microsystem is especially suitable for the pressure measurements in a high radiation environment. (paper)

A Piezoelectric Passive Wireless Sensor for Monitoring Strain

Science.gov (United States)

Zou, Xiyue; Ferri, Paul N.; Hogan, Ben; Mazzeo, Aaron D.; Hull. Patrick V.

2017-01-01

Interest in passive wireless sensing has grown over the past few decades to meet demands in structural health monitoring.(Deivasigamani et al., 2013; Wilson and Juarez, 2014) This work describes a passive wireless sensor for monitoring strain, which does not have an embedded battery or chip. Without an embedded battery, the passive wireless sensor has the potential to maintain its functionality over long periods in remote/harsh environments. This work also focuses on monitoring small strain (less than 1000 micro-?). The wireless sensing system includes a reader unit, a coil-like transponder, and a sensing unit. It operates in the Megahertz (MHz) frequency range, which allows for a few centimeters of separation between the reader and sensing unit during measurements. The sensing unit is a strain-sensitive piezoelectric resonator that maximizes the energy efficiency at the resonance frequency, so it converts nanoscale mechanical variations to detectable differences in electrical signal. In response to an external loading, the piezoelectric sensor breaks from its original electromechanical equilibrium, and the resonant frequency shifts as the system reaches a new balanced equilibrium. In this work, the fixture of the sensing unit is a small, sticker-like package that converts the surface strain of a test material to measurable shifts in resonant frequencies. Furthermore, electromechanical modeling provides a lumped-parameter model of the system to describe and predict the measured wireless signals of the sensor. Detailed characterization demonstrates how this wireless sensor has resolution comparable to that of conventional wired strain sensors for monitoring small strain.

Photoacoustic CO2-Sensor for Automotive Applications

OpenAIRE

Huber, J.; Weber, C.; Eberhardt, A.; Wöllenstein, J.

2016-01-01

We present a field-tested miniaturized spectroscopic CO2 sensor which is based on the photoacoustic effect. The sensor is developed for automotive applications and considers the requirements for the usage in vehicles. The sensor measures two measurement ranges simultaneously: The monitoring of the indoor air quality and the detection of possible leakages of the coolant in CO2 air-conditioning systems. The sensor consists of a miniaturized innovative photoacoustic sensor unit with integrated e...

Development of wireless sensor network for landslide monitoring system

International Nuclear Information System (INIS)

Suryadi; Puranto, Prabowo; Adinanta, Hendra; Tohari, Adrin; Priambodo, Purnomo S

2017-01-01

A wireless sensor network has been developed to monitor soil movement of some observed areas periodically. The system consists of four nodes and one gateway which installed on a scope area of 0.2 Km 2 . Each of nodehastwo types of sensor,an inclinometer and an extensometer. An inclinometer sensor is used to measure the tilt of a structure while anextensometer sensor is used to measure the displacement of soil movement. Each of nodeisalso supported by awireless communication device, a solar power supply unit, and a microcontroller unit called sensor module. In this system, there is also gateway module as a main communication system consistinga wireless communication device, power supply unit, and rain gauge to measure the rainfall intensity of the observed area. Each sensor of inclinometer and extensometer isconnected to the sensor module in wiring system but sensor module iscommunicating with gateway in a wireless system. Those four nodes are alsoconnectedeach other in a wireless system collecting the data from inclinometer and extensometer sensors. Module Gateway istransmitting the instruction code to each sensor module one by one and collecting the data from them. Gateway module is an important part to communicate with not only sensor modules but also to the server. This wireless system wasdesigned toreducethe electric consumption powered by 80 WP solar panel and 55Ah battery. This system has been implemented in Pangalengan, Bandung, which has high intensity of rainfall and it can be seen on the website. (paper)

Mapping landscape service provision of cropland in the urban fringe : the case of Wuhan, China

NARCIS (Netherlands)

Zhou, T.; Koomen, E.; Ke, X.

2016-01-01

People benefit from cropland through food production and a variety of environmental and recreational benefits. However, the provision of the different functions offered by agricultural landscape deteriorates as a consequence of ongoing urban development, especially in urban fringe. To help define

Network compensation for missing sensors

Science.gov (United States)

Ahumada, Albert J., Jr.; Mulligan, Jeffrey B.

1991-01-01

A network learning translation invariance algorithm to compute interpolation functions is presented. This algorithm with one fixed receptive field can construct a linear transformation compensating for gain changes, sensor position jitter, and sensor loss when there are enough remaining sensors to adequately sample the input images. However, when the images are undersampled and complete compensation is not possible, the algorithm need to be modified. For moderate sensor losses, the algorithm works if the transformation weight adjustment is restricted to the weights to output units affected by the loss.

Cryogenic microsize Hall sensors

International Nuclear Information System (INIS)

Kvitkovic, J.; Polak, M.

1993-01-01

Hall sensors have a variety of applications in magnetic field measurements. The active area of the Hall sensor does not play an important role in measuring of homogeneous magnetic field. Actually Hall sensors are widely used to measure profiles of magnetic fields produced by magnetization currents in samples of HTC superconductors, as well as of LTC ones. Similar techniques are used to measure magnetization of both HTC and LTC superconductors. In these cases Hall sensor operates in highly inhomogeneous magnetic fields. Because of that, Hall sensors with very small active area are required. We developed and tested Hall sensors with active area 100 μm x 100 μm - type M and 50 μm x 50 μm - type V. Here we report on the most imporant parameters of these units, as well as on their properties as differential magnetometer. (orig.)

Chronic oiling and long-term effects of the 1986 Galeta spill on fringing mangroves

International Nuclear Information System (INIS)

Garrity, S.D.; Levings, S.C.; Burns, K.A.

1993-01-01

In April 1986, more than 50,000 barrels of crude oil spilled into Bahia las Minas on the central Caribbean coast of Panama, oiling reef flats, sea grasses, coral reefs and mangroves. In August 1986, the authors began a five-year study on the red mangrove (Rhizophora mangle L.) fringe and the plants and animals that live attached to submerged prop roots. This habitat forms an important part of near shore, tropical nursery grounds. In three habitats (wave-washed open shores, channels and lagoons, and interior drainage streams), oil initially coated virtually the entire surface of submerged prop roots and sank more than 20 cm into sediments. Secondary re-oiling was heaviest in sheltered drainage streams where oil continuously leached from sediments, but also occurred on the open coast and in channels. Bivalves in channels and streams were heavily contaminated through at least May 1991. Results show this spill was a chronic source of oil contamination rather than a single point-source event. The epibiota of submerged mangrove roots had not recovered completely in any habitat after five years. Independent of this reduction, the structure of the mangrove fringe significantly changed after oiling, including decreases in the amount of shore fringed with mangroves and in the density and size of submerged prop roots. Overall, the surface area on submerged mangrove roots decreased by 33 percent on the open coast, 38 percent in channels and 74 percent in stream. The combination of chronic re-oiling, damage to epibiotic assemblages, and reductions in the biogenic substrate (submerged prop roots) has decreased the productivity of this tropical nursery area and suggests recovery will be a complex and prolonged process

Fringe pattern analysis for optical metrology theory, algorithms, and applications

CERN Document Server

Servin, Manuel; Padilla, Moises

2014-01-01

The main objective of this book is to present the basic theoretical principles and practical applications for the classical interferometric techniques and the most advanced methods in the field of modern fringe pattern analysis applied to optical metrology. A major novelty of this work is the presentation of a unified theoretical framework based on the Fourier description of phase shifting interferometry using the Frequency Transfer Function (FTF) along with the theory of Stochastic Process for the straightforward analysis and synthesis of phase shifting algorithms with desired properties such

Second harmonic generation: Effects of the multiple reflections of the fundamental and the second harmonic waves on the Maker fringes

Science.gov (United States)

Tellier, Gildas; Boisrobert, Christian

2007-11-01

The Maker fringes technique is commonly used for the determination of nonlinear optical coefficients. In this article, we present a new formulation of Maker fringes in parallel-surface samples, using boundary conditions taking into account the anisotropy of the crystal, the refractive-index dispersion, and the reflections of the fundamental and the second harmonic waves inside the material. Complete expressions for the generated second harmonic intensity are given for birefringent crystals for the case of no pump depletion. A comparison between theory and experimental results is made, showing the accuracy of our theoretical expressions.

Microstructure imaging of the YBCO thin film/MgO substrate interface: HRTEM and Fourier analysis of the Moire fringe pattern

International Nuclear Information System (INIS)

Auzary, S.; Pailloux, F.; Denanot, M.F.; Gaboriaud, R.J.

1998-01-01

Detailed microstructural aspects of the interface between YBaCuO thin films and MgO substrate are studied by means of a Fourier analysis of Moire fringe pattern obtained from HRTEM investigations of plan view samples. The main features of the observations are large, well oriented crystallographic domains surrounded by wide boundaries. HRTEM investigations together with the Fourier analysis show evidence of both orthorhombic and pseudo-tetragonal structure in the YBaCuO film. An accommodation mechanism is suggested from the Fourier analysis of the Moire fringe pattern. (orig.)

Networked sensors for the combat forces

Science.gov (United States)

Klager, Gene

2004-11-01

Real-time and detailed information is critical to the success of ground combat forces. Current manned reconnaissance, surveillance, and target acquisition (RSTA) capabilities are not sufficient to cover battlefield intelligence gaps, provide Beyond-Line-of-Sight (BLOS) targeting, and the ambush avoidance information necessary for combat forces operating in hostile situations, complex terrain, and conducting military operations in urban terrain. This paper describes a current US Army program developing advanced networked unmanned/unattended sensor systems to survey these gaps and provide the Commander with real-time, pertinent information. Networked Sensors for the Combat Forces plans to develop and demonstrate a new generation of low cost distributed unmanned sensor systems organic to the RSTA Element. Networked unmanned sensors will provide remote monitoring of gaps, will increase a unit"s area of coverage, and will provide the commander organic assets to complete his Battlefield Situational Awareness (BSA) picture for direct and indirect fire weapons, early warning, and threat avoidance. Current efforts include developing sensor packages for unmanned ground vehicles, small unmanned aerial vehicles, and unattended ground sensors using advanced sensor technologies. These sensors will be integrated with robust networked communications and Battle Command tools for mission planning, intelligence "reachback", and sensor data management. The network architecture design is based on a model that identifies a three-part modular design: 1) standardized sensor message protocols, 2) Sensor Data Management, and 3) Service Oriented Architecture. This simple model provides maximum flexibility for data exchange, information management and distribution. Products include: Sensor suites optimized for unmanned platforms, stationary and mobile versions of the Sensor Data Management Center, Battle Command planning tools, networked communications, and sensor management software. Details

Fringing-field dielectrophoretic assembly of ultrahigh-density semiconducting nanotube arrays with a self-limited pitch

Science.gov (United States)

Cao, Qing; Han, Shu-Jen; Tulevski, George S.

2014-09-01

One key challenge of realizing practical high-performance electronic devices based on single-walled carbon nanotubes is to produce electronically pure nanotube arrays with both a minuscule and uniform inter-tube pitch for sufficient device-packing density and homogeneity. Here we develop a method in which the alternating voltage-fringing electric field formed between surface microelectrodes and the substrate is utilized to assemble semiconducting nanotubes into well-aligned, ultrahigh-density and submonolayered arrays, with a consistent pitch as small as 21±6 nm determined by a self-limiting mechanism, based on the unique field focusing and screening effects of the fringing field. Field-effect transistors based on such nanotube arrays exhibit record high device transconductance (>50 μS μm-1) and decent on current per nanotube (~1 μA per tube) together with high on/off ratios at a drain bias of -1 V.

Time-domain fiber loop ringdown sensor and sensor network

Science.gov (United States)

Kaya, Malik

Optical fibers have been mostly used in fiber optic communications, imaging optics, sensing technology, etc. Fiber optic sensors have gained increasing attention for scientific and structural health monitoring (SHM) applications. In this study, fiber loop ringdown (FLRD) sensors were fabricated for scientific, SHM, and sensor networking applications. FLRD biosensors were fabricated for both bulk refractive index (RI)- and surface RI-based DNA sensing and one type of bacteria sensing. Furthermore, the effect of glucose oxidase (GOD) immobilization at the sensor head on sensor performance was evaluated for both glucose and synthetic urine solutions with glucose concentration between 0.1% and 10%. Detection sensitivities of the glucose sensors were achieved as low as 0.05%. For chemical sensing, heavy water, ranging from 97% to 10%, and several elemental solutions were monitored by using the FLRD chemical sensors. Bulk index-based FLRD sensing showed that trace elements can be detected in deionized water. For physical sensing, water and cracking sensors were fabricated and embedded into concrete. A partially-etched single-mode fiber (SMF) was embedded into a concrete bar for water monitoring while a bare SMF without any treatment was directly embedded into another concrete bar for monitoring cracks. Furthermore, detection sensitivities of water and crack sensors were investigated as 10 ml water and 0.5 mm surface crack width, respectively. Additionally fiber loop ringdown-fiber Bragg grating temperature sensors were developed in the laboratory; two sensor units for water, crack, and temperature sensing were deployed into a concrete cube in a US Department of Energy test bed (Miami, FL). Multi-sensor applications in a real concrete structure were accomplished by testing the six FLRD sensors. As a final stage, a sensor network was assembled by multiplexing two or three FLRD sensors in series and parallel. Additionally, two FLRD sensors were combined in series and

Accurate characterisation of hole size and location by projected fringe profilometry

Science.gov (United States)

Wu, Yuxiang; Dantanarayana, Harshana G.; Yue, Huimin; Huntley, Jonathan M.

2018-06-01

The ability to accurately estimate the location and geometry of holes is often required in the field of quality control and automated assembly. Projected fringe profilometry is a potentially attractive technique on account of being non-contacting, of lower cost, and orders of magnitude faster than the traditional coordinate measuring machine. However, we demonstrate in this paper that fringe projection is susceptible to significant (hundreds of µm) measurement artefacts in the neighbourhood of hole edges, which give rise to errors of a similar magnitude in the estimated hole geometry. A mechanism for the phenomenon is identified based on the finite size of the imaging system’s point spread function and the resulting bias produced near to sample discontinuities in geometry and reflectivity. A mathematical model is proposed, from which a post-processing compensation algorithm is developed to suppress such errors around the holes. The algorithm includes a robust and accurate sub-pixel edge detection method based on a Fourier descriptor of the hole contour. The proposed algorithm was found to reduce significantly the measurement artefacts near the hole edges. As a result, the errors in estimated hole radius were reduced by up to one order of magnitude, to a few tens of µm for hole radii in the range 2–15 mm, compared to those from the uncompensated measurements.

Integrated active sensor system for real time vibration monitoring.

Science.gov (United States)

Liang, Qijie; Yan, Xiaoqin; Liao, Xinqin; Cao, Shiyao; Lu, Shengnan; Zheng, Xin; Zhang, Yue

2015-11-05

We report a self-powered, lightweight and cost-effective active sensor system for vibration monitoring with multiplexed operation based on contact electrification between sensor and detected objects. The as-fabricated sensor matrix is capable of monitoring and mapping the vibration state of large amounts of units. The monitoring contents include: on-off state, vibration frequency and vibration amplitude of each unit. The active sensor system delivers a detection range of 0-60 Hz, high accuracy (relative error below 0.42%), long-term stability (10000 cycles). On the time dimension, the sensor can provide the vibration process memory by recording the outputs of the sensor system in an extend period of time. Besides, the developed sensor system can realize detection under contact mode and non-contact mode. Its high performance is not sensitive to the shape or the conductivity of the detected object. With these features, the active sensor system has great potential in automatic control, remote operation, surveillance and security systems.

Elimination of image flicker in a fringe-field switching liquid crystal display by applying a bipolar voltage wave.

Science.gov (United States)

Oh, Seung-Won; Park, Jun-Hee; Lee, Ji-Hoon; Yoon, Tae-Hoon

2015-09-07

Recently, low-frequency driving of liquid crystal display (LCD) panels to minimize power consumption has drawn much attention. In the case in which an LCD panel is driven by a fringe-field at a low frequency, the image flickering phenomenon occurs when the sign of the applied electric field is reversed. We investigated image flickering induced by the flexoelectric effect in a fringe-field switching (FFS) liquid crystal cell in terms of the transmittance difference between frames and the ripple phenomenon. Experimental results show that image flicker due to transmittance difference can be eliminated completely and that the ripple phenomena can be reduced significantly by applying a bipolar voltage wave to the FFS cell.

Marshall Islands Fringing Reef and Atoll Lagoon Observations of the Tohoku Tsunami

Science.gov (United States)

Ford, Murray; Becker, Janet M.; Merrifield, Mark A.; Song, Y. Tony

2014-12-01

The magnitude 9.0 Tohoku earthquake on 11 March 2011 generated a tsunami which caused significant impacts throughout the Pacific Ocean. A description of the tsunami within the lagoons and on the surrounding fringing reefs of two mid-ocean atoll islands is presented using bottom pressure observations from the Majuro and Kwajalein atolls in the Marshall Islands, supplemented by tide gauge data in the lagoons and by numerical model simulations in the deep ocean. Although the initial wave arrival was not captured by the pressure sensors, subsequent oscillations on the reef face resemble the deep ocean tsunami signal simulated by two numerical models, suggesting that the tsunami amplitudes over the atoll outer reefs are similar to that in deep water. In contrast, tsunami oscillations in the lagoon are more energetic and long lasting than observed on the reefs or modelled in the deep ocean. The tsunami energy in the Majuro lagoon exhibits persistent peaks in the 30 and 60 min period bands that suggest the excitation of closed and open basin normal modes, while energy in the Kwajalein lagoon spans a broader range of frequencies with weaker, multiple peaks than observed at Majuro, which may be associated with the tsunami behavior within the more irregular geometry of the Kwajalein lagoon. The propagation of the tsunami across the reef flats is shown to be tidally dependent, with amplitudes increasing/decreasing shoreward at high/low tide. The impact of the tsunami on the Marshall Islands was reduced due to the coincidence of peak wave amplitudes with low tide; however, the observed wave amplitudes, particularly in the atoll lagoon, would have led to inundation at different tidal phases.

A hybrid Fabry–Perot/Michelson interferometer sensor using a dual asymmetric core microstructured fiber

International Nuclear Information System (INIS)

Frazão, O; Silva, S F; Viegas, J; Baptista, J M; Santos, J L; Roy, P

2010-01-01

A hybrid Fabry–Perot/Michelson interferometer sensor using a dual asymmetric core microstructured fiber is demonstrated. The hybrid interferometer presents three waves. Two parallel Fabry–Perot cavities with low finesse are formed between the splice region and the end of a dual-core microstructured fiber. A Michelson configuration is obtained by the two small cores of the microstructured fiber. The spectral response of the hybrid interferometer presents two pattern fringes with different frequencies due to the respective optical path interferometers. The hybrid interferometer was characterized in strain and temperature presenting different sensitivity coefficients for each topology. Due to these characteristics, this novel sensing head is able to measure strain and temperature, simultaneously

Displacement, distance, and shape measurements of fast-rotating rough objects by two mutually tilted interference fringe systems.

Science.gov (United States)

Günther, Philipp; Kuschmierz, Robert; Pfister, Thorsten; Czarske, Jürgen W

2013-05-01

The precise distance measurement of fast-moving rough surfaces is important in several applications such as lathe monitoring. A nonincremental interferometer based on two mutually tilted interference fringe systems has been realized for this task. The distance is coded in the phase difference between the generated interference signals corresponding to the fringe systems. Large tilting angles between the interference fringe systems are necessary for a high sensitivity. However, due to the speckle effect at rough surfaces, different envelopes and phase jumps of the interference signals occur. At large tilting angles, these signals become dissimilar, resulting in a small correlation coefficient and a high measurement uncertainty. Based on a matching of illumination and receiving optics, the correlation coefficient and the phase difference estimation have been improved significantly. For axial displacement measurements of recurring rough surfaces, laterally moving with velocities of 5 m/s, an uncertainty of 110 nm has been attained. For nonrecurring surfaces, a distance measurement uncertainty of 830 nm has been achieved. Incorporating the additionally measured lateral velocity and the rotational speed, the two-dimensional shape of rotating objects results. Since the measurement uncertainty of the displacement, distance, and shape is nearly independent of the lateral surface velocity, this technique is predestined for fast-rotating objects, such as crankshafts, camshafts, vacuum pump shafts, or turning parts of lathes.

Manipulation of incoherent and coherent spin ensembles in diluted magnetic semiconductors via ferromagnetic fringe fields; Manipulation inkohaerenter und kohaerenter Spinensembles in verduennt-magnetischen Halbleitern mittels ferromagnetischer Streufelder

Energy Technology Data Exchange (ETDEWEB)

Halm, Simon

2009-05-19

In this thesis it is demonstrated that fringe fields of nanostructured ferromagnets provide the opportunity to manipulate both incoherent and coherent spin ensembles in a dilute magnetic semiconductor (DMS). Fringe fields of Fe/Tb ferromagnets with a remanent out-of-plane magnetization induce a local magnetization in a (Zn,Cd,Mn)Se DMS. Due to the sp-d exchange interaction, optically generated electron-hole pairs align their spin along the DMS magnetization. One obtains a local, remanent spin polarization which was probed by spatially resolved, polarization sensitive photoluminescence spectroscopy. Fringe fields from in-plane magnetized Co ferromagnets allow to locally modify the precession frequency of the Manganese magnetic moments of the DMS in an external magnetic field. This was probed by time-resolved Kerr rotation technique. The inhomogeneity of the fringe field leads to a shortening of the ensemble decoherence time and to the effect of a time-dependent ensemble precession frequency. (orig.)

29 CFR 4.176 - Payment of fringe benefits to temporary and part-time employees.

Science.gov (United States)

2010-07-01

... 29 Labor 1 2010-07-01 2010-07-01 true Payment of fringe benefits to temporary and part-time... to temporary and part-time employees. (a) As set forth in § 4.165(a)(2), the Act makes no distinction, with respect to its compensation provisions, between temporary, part-time, and full-time employees...

SU-E-T-410: Fringe Stability and Phase Shift Measurements in a Michelson Interferometer for Optical Calorimetry

International Nuclear Information System (INIS)

Flores-Martinez, E; Malin, M; DeWerd, L

2014-01-01

Purpose: To identify the variables limiting the resolution of a Michelson interferometer used to measure phase shifts (PS) in water as part of a radiometric calorimeter. Methods: We investigated the output stability of a He-Ne laser and a laser diode. The short and long term stability of the fringe pattern in a Michelson interferometer was tested with different types of lasers, thermal insulation arrangements, damping systems and optical mounts to optimize system performance. PS were induced by electrically heating water in a 1 cm quartz cuvette located in one of the interferometer arms. The PS was calculated from fringe intensity changes and compared to a calculated PS using thermocouple-measured temperature changes in the water. Results: The intensity of the laser diode is more stable, but the gas laser’s profile is more suitable for fringe analysis and has better temporal coherence. The laser requires a warm-up time of 4 hours before its output is stabilized (SNR>95). The fringe’s stability strongly depends on the thermal insulation. When the interferometer is exposed to ambient temperature swings of 0.7 K, it is not possible to stabilize the fringe pattern. Enclosing the system in a 2.5 cm-thick Styrofoam box improves the SNR, but further insulation will be needed to increase the SNR above 50. High frequency noise is significantly reduced by damping the system.Inducing a temperature rise in water, starting at 299 K, the average temperature increase for a 2π PS is 0.29 ± 0.02 K and the proportionality constant is -21.1 ± 0.8 radians/K. This is 5.8% lower than the calculated value using the thermocouple. Conclusion: Interferometric PS measurements of temperature may provide an alternative to thermistors for water calorimetry. The resolution of the current prototype is limited by ambient temperature stability. Calculated and measured thermally-induced PS in water agreed to within 5.8%

Fringe pattern information retrieval using wavelets

Science.gov (United States)

Sciammarella, Cesar A.; Patimo, Caterina; Manicone, Pasquale D.; Lamberti, Luciano

2005-08-01

Two-dimensional phase modulation is currently the basic model used in the interpretation of fringe patterns that contain displacement information, moire, holographic interferometry, speckle techniques. Another way to look to these two-dimensional signals is to consider them as frequency modulated signals. This alternative interpretation has practical implications similar to those that exist in radio engineering for handling frequency modulated signals. Utilizing this model it is possible to obtain frequency information by using the energy approach introduced by Ville in 1944. A natural complementary tool of this process is the wavelet methodology. The use of wavelet makes it possible to obtain the local values of the frequency in a one or two dimensional domain without the need of previous phase retrieval and differentiation. Furthermore from the properties of wavelets it is also possible to obtain at the same time the phase of the signal with the advantage of a better noise removal capabilities and the possibility of developing simpler algorithms for phase unwrapping due to the availability of the derivative of the phase.

Fringe Field Effects on Bending Magnets, Derived for TRANSPORT/TURTLE

Energy Technology Data Exchange (ETDEWEB)

Molloy, Riley [Arizona State Univ., Tempe, AZ (United States); Blitz, Sam [Arizona State Univ., Tempe, AZ (United States)

2013-08-05

A realistic magnetic dipole has complex effects on a charged particle near the entrance and exit of the magnet, even with a constant and uniform magnetic field deep within the interior of the magnet. To satisfy Maxwell's equations, the field lines near either end of a realistic magnet are significantly more complicated, yielding non-trivial forces. The effects of this fringe field are calculated to first order, applying both the paraxial and thin lens approximations. We find that, in addition to zeroth order effects, the position of a particle directly impacts the forces in the horizontal and vertical directions.

Slot-waveguide biochemical sensor.

Science.gov (United States)

Barrios, Carlos A; Gylfason, Kristinn B; Sánchez, Benito; Griol, Amadeu; Sohlström, H; Holgado, M; Casquel, R

2007-11-01

We report an experimental demonstration of an integrated biochemical sensor based on a slot-waveguide microring resonator. The microresonator is fabricated on a Si3N4-SiO2 platform and operates at a wavelength of 1.3 microm. The transmission spectrum of the sensor is measured with different ambient refractive indices ranging from n=1.33 to 1.42. A linear shift of the resonant wavelength with increasing ambient refractive index of 212 nm/refractive index units (RIU) is observed. The sensor detects a minimal refractive index variation of 2x10(-4) RIU.

Self organization of wireless sensor networks using ultra-wideband radios

Science.gov (United States)

Dowla, Farid U [Castro Valley, CA; Nekoogar, Franak [San Ramon, CA; Spiridon, Alex [Palo Alto, CA

2009-06-16

A novel UWB communications method and system that provides self-organization for wireless sensor networks is introduced. The self-organization is in terms of scalability, power conservation, channel estimation, and node synchronization in wireless sensor networks. The UWB receiver in the present invention adds two new tasks to conventional TR receivers. The two additional units are SNR enhancing unit and timing acquisition and tracking unit.

A survey on the wireless sensor network technology

International Nuclear Information System (INIS)

Kim, Jae Hee; Jun, Hyeong Seop; Lee, Jae Cheol; Choi, Yoo Rak

2007-12-01

Wireless sensor technology is required in the safety inspection for safety-critical unit of nuclear power plant. This report describes wireless sensor technology related with the project named 'Development of a remote care system of NPP components based on the network and safety database'. This report includes contents of methodology and status of sensor network construction, status of zigbee sensor network, problem of security and sensor battery. Energy harvesting technology will be mentioned on the next report

Micro/Nano-scale Strain Distribution Measurement from Sampling Moiré Fringes.

Science.gov (United States)

Wang, Qinghua; Ri, Shien; Tsuda, Hiroshi

2017-05-23

This work describes the measurement procedure and principles of a sampling moiré technique for full-field micro/nano-scale deformation measurements. The developed technique can be performed in two ways: using the reconstructed multiplication moiré method or the spatial phase-shifting sampling moiré method. When the specimen grid pitch is around 2 pixels, 2-pixel sampling moiré fringes are generated to reconstruct a multiplication moiré pattern for a deformation measurement. Both the displacement and strain sensitivities are twice as high as in the traditional scanning moiré method in the same wide field of view. When the specimen grid pitch is around or greater than 3 pixels, multi-pixel sampling moiré fringes are generated, and a spatial phase-shifting technique is combined for a full-field deformation measurement. The strain measurement accuracy is significantly improved, and automatic batch measurement is easily achievable. Both methods can measure the two-dimensional (2D) strain distributions from a single-shot grid image without rotating the specimen or scanning lines, as in traditional moiré techniques. As examples, the 2D displacement and strain distributions, including the shear strains of two carbon fiber-reinforced plastic specimens, were measured in three-point bending tests. The proposed technique is expected to play an important role in the non-destructive quantitative evaluations of mechanical properties, crack occurrences, and residual stresses of a variety of materials.