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Selected AbstractsAbout 200 years after Mohs , Nanoscratching LiB3O5CRYSTAL RESEARCH AND TECHNOLOGY, Issue 11 2008P. Paufler Abstract Though simple scratch hardness tests after Mohs are still used today, the development of diamond nanoscratching equipment offers new possibilities to meet demands of modern nanotechnology. Preceding approaches to assign hardness values to materials are briefly reviewed, and scratch hardness is related to indentation hardness. Taking single-crystalline LiB3O5 as an example, the dependence of scratch morphology on the direction of scratching is demonstrated quantitatively. The coefficient of friction depends on normal load and varies between 0.25 and 0.37. Moreover, it is oscillating during scratching thus reflecting processes at nanoscale. Dislocation etch pits were observed due to scratching. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A perturbation analysis of harmonic generation from saturated elements in power systemsELECTRICAL ENGINEERING IN JAPAN, Issue 4 2010Teruhisa Kumano Abstract Nonlinear phenomena such as saturation of magnetic flux have considerable effects in power systems analysis. It is reported that a failure in a real 500-kV system triggered islanding operation, where resultant even harmonics caused malfunctions in protective relays. It is also reported that the major origin of this wave distortion is nothing but unidirectional magnetization of the transformer iron core. Time simulation is widely used today to analyze phenomena of this type, but it has basically two shortcomings. One is that the time simulation takes too much computing time in the vicinity of inflection points in the saturation characteristic curve because certain iterative procedures such as N-R (Newton,Raphson) must be used and such methods tend to be caught in an ill-conditioned numerical hunting. The other is that such simulation methods sometimes do not aid an intuitive understanding of the studied phenomenon because all of the nonlinear equations are treated in matrix form and are not properly divided into understandable parts, as is done in linear systems. This paper proposes a new computation scheme that is based on the so-called perturbation method. Magnetic saturation of iron cores in a generator and a transformer are taken into account. The proposed method has a special feature to deal with the first shortcoming of the N-R-based time simulation method stated above. The proposed method does not use an iterative process to reduce the equation residue, but uses perturbation series, so that it is free of the ill-conditioning problem. The user need only calculate the perturbation terms one by one until the necessary accuracy is attained. In a numerical example treated in the present paper, first-order perturbation can achieve reasonably high accuracy, which means very fast computing time. In a numerical study, three nonlinear elements are considered. The calculation results are almost identical to the conventional N-R-based time simulation, which shows the validity of the method. The proposed method can be effectively used in screening where many case studies are needed. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(4): 35,42, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20895 [source] The generation of hexahedral meshes for assembly geometry: survey and progress,INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2001Timothy J. Tautges Abstract The finite element method is being used today to model component assemblies in a wide variety of application areas, including structural mechanics, fluid simulations, and others. Generating hexahedral meshes for these assemblies usually requires the use of geometry decomposition, with different meshing algorithms applied to different regions. While the primary motivation for this approach remains the lack of an automatic, reliable all-hexahedral meshing algorithm, requirements in mesh quality and mesh configuration for typical analyses are also factors. For these reasons, this approach is also sometimes required when producing other types of unstructured meshes. This paper will review progress to date in automating many parts of the hex meshing process, which has halved the time to produce all-hex meshes for large assemblies. Particular issues which have been exposed due to this progress will also be discussed, along with their applicability to the general unstructured meshing problem. Published in 2001 by John Wiley & Sons, Ltd. [source] Ancient Remotely-Operated Instruments Recovered Under Water off the Israeli CoastINTERNATIONAL JOURNAL OF NAUTICAL ARCHAEOLOGY, Issue 2 2008Ehud Galili Underwater archaeological investigations in Israel have recovered instruments intended to be operated under water from a vessel on the surface, at depths and times beyond the ability of free divers. Some of these remotely-operated devices, including salvaging-rings, coral-harvesting devices, and grapnels, are described, classified and discussed. These humble but efficient instruments, the prototypes of sophisticated modern instruments, fulfilled necessary tasks in antiquity and are still being used today by traditional fishermen. © 2008 The Authors [source] EFFECTS OF PRETREATMENT WITH ROSEMARY (ROSMARINUS OFFICINALIS L.) IN THE PREVENTION OF LIPID OXIDATION IN SALTED TILAPIA FILLETSJOURNAL OF FOOD QUALITY, Issue 5 2008M. DA SILVA AFONSO ABSTRACT To delay lipid oxidation during meat processing, synthetic antioxidants have been used in the food industry, but the consumers' concern over their toxicity increased interest in research with natural antioxidants. The aim of this work was to analyze the water activity (Aw), thiobarbituric acid reactive substances (TBARS), moisture and trichloroacetic acid-soluble nitrogen (TCASN) in brined tilapia fillets treated or pretreated with natural rosemary extract (Rosmarinus officinalis) and stored for 240 days at ,18C. Higher Aw (0.900 ± 0.010) and moisture (70.13 ± 0.20) values were observed in the pretreated fillets. The TBARS values in the treatment (3.31 ± 0.79) and pretreatment (3.39 ± 0.53) were half the value of the control treatment (6.14 ± 1.21) at 240 days. Statistical differences were observed in TCASN values in 180 (0.112 ± 0.020) and 240 (0.132 ± 0.017) days, with the pretreatment showing a more protective effect in protein oxidation. In this study, rosemary proved to be protective during the frozen storage, especially when its extract was used as pretreatment, before the salting process. PRACTICAL APPLICATIONS Fish consumption is highly elastic, because the annual average consumption of seafood per person in Brazil is only 6.8 kg. The federal government has set a goal to increase it to 12 kg by 2007. Salting is an older food preservation process still used today, and is extremely important because, despite advances in food technology, increased monitoring and improved knowledge, it is emphasized as an easy, cheap and effective process that does not require refrigeration. Tilapia is a highly prolific fish, with a production volume that is increasingly higher each year in Brazil. Therefore, it calls for interesting research to allow an increased shelf life for this species. [source] Remifentanil and the brainACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2008V. FODALE Background and aim: Remifentanil is an ultra-short-acting opioid, increasingly used today in neuroanesthesia and neurointensive care. Its characteristics make remifentanil a potentially ideal agent, but previous data have cast a shadow on this opioid, supporting potentially toxic effects on the ischemic brain. The aim of the present concise review is to survey available up-to-date information on the effects of remifentanil on the central nervous system. Method: A MEDLINE search within the past seven years for available up-to-date information on remifentanil and brain was performed. Results: Concise up-to-date information on the effects of remifentanil on the central nervous system was reported, with a particular emphasis on the following topics: cerebral metabolism, electroencephalogram, electrocorticography, motor-evoked potentials, regional cerebral blood flow, cerebral blood flow velocity, arterial hypotension and hypertension, intracranial pressure, cerebral perfusion pressure, cerebral autoregulation, cerebrovascular CO2 reactivity, cerebrospinal fluid, painful stimulation, analgesia and hyperalgesia, neuroprotection, neurotoxicity and hypothermia. Conclusion: The knowledge of the influence of remifentanil on brain functions is crucial before routine use in neuroanesthesia to improve anesthesia performance and patient safety as well as outcome. [source] A review of the thoracic splanchnic nerves and celiac gangliaCLINICAL ANATOMY, Issue 5 2010Marios Loukas Abstract Anatomical variation of the thoracic splanchnic nerves is as diverse as any structure in the body. Thoracic splanchnic nerves are derived from medial branches of the lower seven thoracic sympathetic ganglia, with the greater splanchnic nerve comprising the more cranial contributions, the lesser the middle branches, and the least splanchnic nerve usually T11 and/or T12. Much of the early anatomical research of the thoracic splanchnic nerves revolved around elucidating the nerve root level contributing to each of these nerves. The celiac plexus is a major interchange for autonomic fibers, receiving many of the thoracic splanchnic nerve fibers as they course toward the organs of the abdomen. The location of the celiac ganglia are usually described in relation to surrounding structures, and also show variation in size and general morphology. Clinically, the thoracic splanchnic nerves and celiac ganglia play a major role in pain management for upper abdominal disorders, particularly chronic pancreatitis and pancreatic cancer. Splanchnicectomy has been a treatment option since Mallet-Guy became a major proponent of the procedure in the 1940s. Splanchnic nerve dissection and thermocoagulation are two common derivatives of splanchnicectomy that are commonly used today. Celiac plexus block is also a treatment option to compliment splanchnicectomy in pain management. Endoscopic ultrasonography (EUS)-guided celiac injection and percutaneous methods of celiac plexus block have been heavily studied and are two important methods used today. For both splanchnicectomies and celiac plexus block, the innovation of ultrasonographic imaging technology has improved efficacy and accuracy of these procedures and continues to make pain management for these diseases more successful. Clin. Anat. 23:512,522, 2010. © 2010 Wiley-Liss, Inc. 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