Non-contact ultrasonic inspection by Gas-Coupled Laser Acoustic Detection (GCLAD).

Gas-Coupled Laser Acoustic Detection (GCLAD) is an ultrasonic, non-contact detection technique that has been recently proven to be applicable to the inspection of mechanical components. GCLAD response raises as the intersection length between the probe laser beam and the acoustic wavefront propagating in the air increases; such feature differentiates the GCLAD device from other optical detection instruments, making it a line detection system rather than a point detector. During the inspection of structures mainly extending in two dimensions, the capability to evidence presence of defects in whichever point over a line would enable moving the emitter and the detector along a single direction: this translates in the possibility to decrease the overall required time for interrogation of components compared to point detectors, as well as generating simpler automated monitoring layouts.

Utilization of image phase information to achieve super-sampling.

For image phase-based super-sampling, an image sequence consisting of slightly displaced frames is up-sampled, aligned, and averaged into a single larger image that possesses image resolution exceeding the limitations of the imaging system. This process obtains a significant portion of high-resolution phase information and models the missing magnitude using deconvolution or reconstruction algorithms. Three simulations are presented in which a 32-frame sequence with the size 256 by 256 pixels is processed to create a single 4096 by 4096 pixel image with pixel level resolution.

Extracting flat-field images from scene-based image sequences using phase correlation.

Flat-field image processing is an essential step in producing high-quality and radiometrically calibrated images. Flat-fielding corrects for variations in the gain of focal plane array electronics and unequal illumination from the system optics. Typically, a flat-field image is captured by imaging a radiometrically uniform surface.

Frequency response of optical beam deflection by ultrasound in water.

Acoustic waveforms create fluctuations in the index of refraction of the medium. An optical beam passing through the disturbance will be deflected or displaced from the original path. The acoustic wave can be detected by sending a laser through the disturbance and sensing the path changes of the beam with a position-sensitive photodetector.

A DArT marker genetic map of perennial ryegrass (Lolium perenne L.) integrated with detailed comparative mapping information; comparison with existing DArT marker genetic maps of Lolium perenne, L. multiflorum and Festuca pratensis.

Background: Ryegrasses and fescues (genera, Lolium and Festuca) are species of forage and turf grasses which are used widely in agricultural and amenity situations. They are classified within the sub-family Pooideae and so are closely related to Brachypodium distachyon, wheat, barley, rye and oats. Recently, a DArT array has been developed which can be used in generating marker and mapping information for ryegrasses and fescues.

Generation of ultrasound in materials using continuous-wave lasers.

Generating and detecting ultrasound is a standard method of nondestructive evaluation of materials. Pulsed lasers are used to generate ultrasound remotely in situations that prohibit the use of contact transducers. The scanning rate is limited by the repetition rates of the pulsed lasers, ranging between 10 and 100 Hz for lasers with sufficient pulse widths and energies.

Application of a scattered-light radiometric power meter.

The power measurement of high-power continuous-wave laser beams typically calls for the use of water-cooled thermopile power meters. Large thermopile meters have slow response times that can prove insufficient to conduct certain tests, such as determining the influence of atmospheric turbulence on transmitted beam power. To achieve faster response times, we calibrated a digital camera to measure the power level as the optical beam is projected onto a white surface.

Alien introgression in the grasses Lolium perenne (perennial ryegrass) and Festuca pratensis (meadow fescue): the development of seven monosomic substitution lines and their molecular and cytological characterization.

Background And Aims: To address the issues associated with food security, environmental change and bioenergy in the context of crop plants, the production, identification and evaluation of novel plant phenotypes is fundamental. One of the major routes to this end will be wide hybridization and introgression breeding. The transfer of chromosomes and chromosome segments between related species (chromosome engineering or alien introgression) also provides an important resource for determining the genetic control of target traits.

Accumulation of chlorophyll catabolites photosensitizes the hypersensitive response elicited by Pseudomonas syringae in Arabidopsis.

• The staygreen (SGR) gene encodes a chloroplast-targeted protein which promotes chlorophyll degradation via disruption of light-harvesting complexes (LHCs). • Over-expression of SGR in Arabidopsis (SGR-OX) in a Columbia-0 (Col-0) background caused spontaneous necrotic flecking. To relate this to the hypersensitive response (HR), Col-0, SGR-OX and RNAi SGR (SGRi) lines were challenged with Pseudomonas syringae pv tomato (Pst) encoding the avirulence gene avrRpm1.

Nondestructive analysis of senescence in mesophyll cells by spectral resolution of protein synthesis-dependent pigment metabolism.

* Over 6 d of dark-induced senescence, leaf segments of wild-type Lolium temulentum lost > 96% chlorophyll a + b; leaves from plants containing a staygreen mutation introgressed from Festuca pratensis, which has a lesion in the senescence-associated fragmentation of pigment-proteolipid complexes, retained over 43% of total chlorophyll over the same period. * Mutant segments preferentially retained thylakoid membrane proteins (exemplified by LHCP II) but lost other cellular proteins at the same rate as wild-type tissue. The protein synthesis inhibitor D-MDMP inhibited chlorophyll degradation and partially prevented protein loss in both genotypes, but tissues treated with the ineffective L-stereoisomer were indistinguishable from water controls.

Modification of nitrogen remobilization, grain fill and leaf senescence in maize (Zea mays) by transposon insertional mutagenesis in a protease gene.

A maize (Zea mays) senescence-associated legumain gene, See2beta, was characterized at the physiological and molecular levels to determine its role in senescence and resource allocation. A reverse-genetics screen of a maize Mutator (Mu) population identified a Mu insertion in See2beta. Maize plants homozygous for the insertion were produced.

Cross-species identification of Mendel's I locus.

A key gene involved in plant senescence, mutations of which partially disable chlorophyll catabolism and confer stay-green leaf and cotyledon phenotypes, has been identified in Pisum sativum, Arabidopsis thaliana, and Festuca pratensis by using classical and molecular genetics and comparative genomics. A stay-green locus in F. pratensis is syntenically equivalent to a similar stay-green locus on rice chromosome 9.

Rapid supersampling of multiframe sequences by use of blind deconvolution.

Under certain conditions, multiframe image sequences can be processed to produce images that achieve greater resolution through image registration and increased sampling. This technique, known as supersampling, takes advantage of the spatiotemporal data available in an undersampled imaging sequence. In this effort the image registration is replaced by application of a fast blind-deconvolution technique to remove the motion blur in the upsampled average of the image sequence.

Blind deconvolution of audio-frequency signals using the self-deconvolving data restoration algorithm.

A signal processing algorithm has been developed in which a filter function is extracted from degraded data through mathematical operations. The filter function can be used to restore much of the degraded content of the data through use of a deconvolution process. The operation can be performed without prior knowledge of the detection system, a technique known as blind deconvolution.

Analysis of the chlorophyll catabolism pathway in leaves of an introgression senescence mutant of Lolium temulentum.

Pigments, proteins and enzyme activity related to chlorophyll catabolism were analysed in senescing leaves of wild-type (WT) Lolium temulentum and compared with those of an introgression line carrying a mutant gene from stay-green (SG) Festuca pratensis. During senescence of WT leaves chlorophylls a and b were continuously catabolised to colourless products and no other derivatives were observed, whereas in SG leaves there was an accumulation of dephytylated and oxidised catabolites including chlorophyllide a, phaeophorbide a and 13(2) OH-chlorophyllide a. Dephytylated products were absent from SG leaf tissue senescing under a light-dark cycle.

Noniterative blind data restoration by use of an extracted filter function.

A signal-processing algorithm has been developed where a filter function is extracted from degraded data through mathematical operations. The filter function can then be used to restore much of the degraded content of the data through use of a deconvolution algorithm. This process can be performed without prior knowledge of the detection system, a technique known as blind deconvolution.