Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Research into terahertz technology is now receiving increasing attention around the world, and devices exploiting this waveband are set to become increasingly important in a very diverse range of applications. Here, an overview of the status of the technology, its uses and its future prospects are presented.

Cutting-edge terahertz technology

The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

American Society for Testing and Materials

Terahertz spectroscopy systems use far-infrared radiation to extract molecular spectral information in an otherwise inaccessible portion of the electromagnetic spectrum. Materials research is an essential component of modern terahertz systems: novel, higher-power terahertz sources rely heavily on new materials such as quantum cascade structures. At the same time, terahertz spectroscopy and imaging provide a powerful tool for the characterization of a broad range of materials, including semiconductors and biomolecules.

Materials for terahertz science and technology

Over the past three decades a new spectroscopic technique with unique possibilities has emerged. Based on coherent and time-resolved detection of the electric field of ultrashort radiation bursts in the far-infrared, this technique has become known as terahertz time-domain spectroscopy (THz-TDS). In this review article the authors describe the technique in its various implementations for static and time-resolved spectroscopy, and illustrate the performance of the technique with recent examples from solid-state physics and physical chemistry as well as aqueous chemistry. Examples from other fields of research, where THz spectroscopic techniques have proven to be useful research tools, and the potential for industrial applications of THz spectroscopic and imaging techniques are discussed.

Terahertz spectroscopy and imaging – Modern techniques and applications

Terahertz spectroscopy of crystalline and non-crystalline solids is probably one of the most active research fields within the terahertz community. Many potential applications, amongst which spectral recognition is probably one of the most prominent, have significantly stimulated the development of commercial systems and have spurred an increased technical advancement. However, the topic is very complex and multifaceted. Therefore, it is beyond the scope of this chapter to provide a fully comprehensive review of the works performed in this area. We would rather like to demonstrate, based on some selected examples, the potential the technique holds for various different applications. A particular focus will be given to data analysis and, in particular, how we may account for effects resulting from non-ideal sample preparation.

Terahertz Spectroscopy of Crystalline and Non-Crystalline Solids

We present a complete approach to highly efficient image registration for embedded systems, covering all steps from theory to practice. An optimization-based image registration algorithm using a least-squares data term is implemented on an embedded distributed multicore digital signal processor (DSP) architecture. All relevant parts are optimized, ranging from mathematics, algorithmics, and data transfer to hardware architecture and electronic components. The optimization for the rigid alignment of two-dimensional images is performed in a multilevel Gauss–Newton minimization framework. We propose a reformulation of the necessary derivative computations, which eliminates all sparse matrix operations and allows for parallel, memory-efficient computation. The pixelwise parallellism forms an ideal starting point for our implementation on a multicore, multichip DSP architecture. The reduction of data transfer to the particular DSP chips is key for an efficient calculation. By determining worst cases for the subimages needed on each DSP, we can substantially reduce data transfer and memory requirements. This is accompanied by a sophisticated padding mechanism that eliminates pipeline hazards and speeds up the generation of the multilevel pyramid. Finally, we present a reference hardware architecture consisting of four TI C6678 DSPs with eight cores each. We show that it is possible to register high-resolution images within milliseconds on an embedded device. In our example, we register two images with 4096 × 4096 pixels within 93 ms, while off-loading the CPU by a factor of 20 and requiring 3.12 times less electrical energy.

Highly efficient image registration for embedded systems using a distributed multicore DSP architecture

In image registration of medical data a common and challenging problem is handling intensity-inhomogeneities. These inhomogeneities appear for instance in images of serially sectioned brains caused by the histological staining process or in medical imaging with contrast agents. Beneath this, natural outliers (for instance cells or vessels) produced by the underlying material itself may be mistaken as noise. Both image registration applications have in common that the well known sum of squared differences (SSD) measure would detect false differences. To deal with these kinds of problems, we supplement the common SSD-measure with image derivatives of higher order. Additionally we introduce a non-quadratic penalizer function to the distance measure leading to robust energy. The concepts are well known in optical flow. Overall, we present a variational model which combines all of these properties. This formulation leads to a fast and efficient algorithm. We demonstrate its applicability at the problems described above.

Robust and staining-invariant elastic registration of a series of images from histologic slices

A terahertz amplitude switching device is proposed which allows for the efficient manipulation of sharp transmission bands. The switching concept is based on the thermally triggered insulator-to-metal transition of a thin vanadium dioxide layer, placed inside a Fabry–Perot resonator.

Switchable THz Filter Based on a Vanadium Dioxide Layer Inside a Fabry–Pérot Cavity

Terahertz radiation or T-rays, show promise in quality control of food products. As T-rays are inherently sensitive to water, they are very suitable for moisture detection. This proves to be a valuable asset in detecting the moisture content of dried food, a critical area for some products. As T-rays are transparent to plastics, food
additives can also be probed through the packaging, providing checks against a manufacturer's claims, such as the presence of certain substances in foods.

/pdf/towards-quality-control-of-food-using-terahertz-uf17rpslda.pdf

Bernd M. Fischer

Papers

Terahertz Spectroscopy of Crystalline and Non-Crystalline Solids

Highly efficient image registration for embedded systems using a distributed multicore DSP architecture

Robust and staining-invariant elastic registration of a series of images from histologic slices

Switchable THz Filter Based on a Vanadium Dioxide Layer Inside a Fabry–Pérot Cavity

Towards quality control of food using terahertz