In order to understand the mechanism of the effects of ground supports and reinforcements on tunnel stability, numerical simulations are conducted using the distinct element method. Four cases of ...simulations are carried out in this paper for tunnels excavated in a sandy ground to investigate the effects of (1) dowels and a lining on a single tunnel, (2) dowels and a lining on two parallel tunnels, (3) forepoling and face bolts on a single tunnel face, and (4) forepoling and face bolts on two tunnels which face each other. It is found that the use of ground supports causes a discontinuous ground to behave as a continuous one. In addition, it is revealed that supports help to form ground arches in the sandy ground. Detailed discussions are given considering the stress paths and the stress distributions.
Powderpost beetle, Lyctus africanus, is a common dry wood pest in the tropical region. The insect pest damages wood by converting the wood into powdery frass. The damaged wood is created by larvae of ...L. africanus which digests the starchy wood part into powdery form. The powdery form developed in exit holes from which Lyctus emerges is an indicator of an active infestation. However, the presence of frass could be detected in the delayed period. Developing prevention of Lyctus entrance into the wood is crucial to minimize the losses. Monitoring the Lyctus infestation regularly, as chemical communication practice, leads to green technology in the pest control system. The chemical communication in Lyctus beetle was identified as the pheromone detected in male Lyctus beetle. In contrast, the female crude extract was observed to show none of the attractant behavior. In this study, the activity of female crude extract of Lyctus on the behaviour of the beetle was observed. The extract was from hexane washed of newly emerged female beetle for 24 h. Chemical analysis by GC-MS indicated dominancy of hydrocarbon compounds in the female crude extract. Purification of the hydrocarbon fraction was then conducted in SiO2 column with hexane solvent. Then, a preference test of the compounds against both male and female beetle was supervised in the Petri dish method. Result of the preference test indicated a repulsion behavior of both female and male beetles. Furthermore, the purified compound increased the repulsion behavior of Lyctus beetle. The hydrocarbon is suggested as a specific compound of female beetle which alters the behaviour of Lyctus beetle.
Abstract
Field monitoring is essential for assessing the stability of natural as well as well-designed slopes to confirm the validity of the design. Many instruments and systems are available for ...monitoring the slope behavior. Interpretation of the monitoring results for assessing the stability of slopes is an important task. Displacements are usually plotted versus time, and their transition and rate of increase are observed and compared with the criteria. This is a common and useful practice, but it is based on an empirical method. Therefore, a method for assessing the stability of slopes on the basis of rock mechanics is required. This paper outlines a back analysis method originally proposed by Sakurai in 1987 to estimate the factor of safety from the measured displacements. Two case studies are demonstrated to confirm the validity of the method. By applying the back analysis method to natural and well-designed slopes, the time transition of the factor of safety can be estimated from the measured displacements. The applicability and limitations of the method are also discussed.
More than 1·5 million people live in or near the Phlegrean Volcanic District (PVD) in southern Italy, which represents one of the most carefully studied volcanic hazard areas in the world. Throughout ...its history, the style of volcanic activity has varied greatly, from relatively quiescent lava flows to explosive phreatomagmatic eruptions. The goal of this study is to develop a more detailed understanding of the physical and chemical processes associated with the Solchiaro eruption in the PVD. The PVD includes three volcanic fields: the Campi Flegrei (CF) caldera and the volcanic islands of Ischia and Procida. The Solchiaro eruption on the island of Procida is one of the few primitive (less evolved) eruptions in the PVD and can provide information on the source of the more evolved magmas associated with this volcanic system. One of the more important chemical parameters that determine the style of volcanic eruptions is the volatile budget of the magma before and during eruption. Melt inclusions (MI) provide the most direct information on the volatile contents of the pre-eruptive melt in the source region for the PVD. The composition of the melt phase before eruption was determined by analyzing the major, minor and trace element and volatile contents of 109 MI in olivine from four samples of the Solchiaro eruption, representing different stratigraphic heights in the deposits and, therefore, different relative times of eruption. Olivine compositions vary from Fo82 to Fo88, with one maximum value of Fo90. The compositions of the MI in olivine were corrected for post-entrapment crystallization (PEC) and for Fe loss by diffusion. Most (97 out of 109) of the MI studied are classified as 'normal' MI because they show chemical evolution trends consistent with that of bulk-rocks from the PVD. Two types of anomalous MI were also recognized based on their major and trace element compositions: (1) Sr-rich MI, and (2) enriched MI that are variably enriched in TiO2, K2O, P2O5, large ion lithophile elements, high field strength elements and rare earth elements relative to 'normal' MI. These MI probably originated from dissolution-reaction-mixing processes in the mush zone of the magma body. 'Normal' MI include both bubble-bearing and bubble-free (containing only glass ± trapped chromite) types. Bubble-free MI most closely record the pre-eruptive volatile content of the melt over a range of temporal and spatial conditions. The observed trends in CO2 contents of MI versus crystallization indicators (e.g. Al2O3/CaO) support the interpretation that variations in the volatile contents of bubble-free MI reflect real variations in the volatile budget of the melt during the evolution of the magma. The correlation between CO2 contents of MI and the relative stratigraphic position of each sample is consistent with eruption of a volatile-saturated magma that initially ascended through the crust from an original depth of at least 8 km. The magma ponded at 4-2 km depth prior to eruption and crystallization and the concomitant volatile exsolution from the saturated melt in the shallow chamber triggered the Solchiaro eruption. As the eruption proceeded, the Solchiaro magma continued to ascend through the crust to a final storage depth of about 1 km.
BL-6A at the Photon Factory is new small-angle X-ray scattering beamline. The light source makes use of a bending magnet, and the available wavelength, monochromatized by a Johann type crystal ...monochromator, is fixed to 1.5 Å. Various kinds of detectors for SAXS and WAXS experiments are installed in BL-6A, and a SAXS/WAXS simultaneous measurement system was also constructed. This beamline is maintained to measure various samples, such as protein solutions, fibers, liquid crystals as well as solid state materials.
Abstract This study aimed to evaluate stress in the bone when an orthodontic mini-implant is close to the roots of adjacent teeth using finite element models (FEMs), and to investigate the causes of ...the high implant failure rate in the mandible. Four FEMs were used: the implant touches nothing; the implant touches the surface of the periodontal membrane; part of the screw thread is embedded in the periodontal membrane; and the implant touches the root. The effect of cortical bone thickness was evaluated using values of 1, 2 and 3 mm. Maximum stress value and stress distribution on the bone elements was determined. Maximum stress on the bone increased when the mini-implant was close to the root. When the implant touched the root, stress increased to 140 MPa or more, and bone resorption could be predicted. Stress was higher for a cortical bone thickness of 2 mm than for other thicknesses. Cortical bone 2 mm thick had a higher risk for bone resorption. A mandible with an average cortical bone thickness of 2 mm may have a higher risk for implant loosening than a maxilla with the same degree of root proximity, which may be related to the lower success rate in the mandible.
We here addressed the basic question, how does extrachromosomal DNA behave when it is placed in the nuclear or the cytoplasmic environment and how is it eliminated? To do this, we tracked ...microinjected DNA molecules in live cells. In the cytoplasm, the diffusion of microinjected DNA was inhibited in a size- and linearity-dependent manner, probably by the intermediate filament. This was followed by the rapid disappearance of the DNA fluorescent signal. In the nucleus, the diffusion was also dependent on the size of the molecule and was accompanied by the aggregation of the DNA. The aggregation may be due to a putative DNA-binding molecule, whose level is high during the G1 phase. Surprisingly, the injected DNA could move across the nuclear membrane and appeared in the cytoplasm, which suggests the presence of a transport system. The intracytoplasmic behavior and the elimination of such DNA was obviously different from the DNA that was directly injected at the cytoplasm. The DNA remaining in the nucleus appeared to be stable and persisted in the nucleus or, after cell division, in the cytoplasm, for more than one cell cycle. These findings provide a novel and basic understanding of the behavior and elimination of a wide variety of extrachromosomal genetic material.
Pb isotopic measurements in olivine-hosted melt inclusions of ocean island basalts (OIBs) from São Miguel, Azores, reflect the high 207Pb/204Pb and 208Pb/204Pb at a given 206Pb/204Pb of their host ...lavas. The data are consistent with mixing between two endmembers: the first (the Central Group) has relatively high 208Pb/206Pb and is similar to the component sampled by Graciosa and Faial, and the second is a radiogenic endmember (with low 208Pb/206Pb) that we refer to as the Nordeste component. F and Cl concentrations measured in the same melt inclusions from São Miguel represent parental abundances unmodified by crustal assimilation. Based on undegassed F and Cl concentrations, the source beneath São Miguel is volatile-rich. Pb-isotope composition of the melt inclusions correlates positively with S concentration: we attribute this correlation to the dissolution of oceanic crust sulfides in the S-undersaturated basaltic melt of the Nordeste component. These blebs were then assimilated by the São Miguel magma and the magma droplets were later trapped in olivines.
When comparing melt inclusions from worldwide OIBs representing mantle endmembers, we find an overall negative correlation between F/Nd and 208Pb/206Pb for volcanic glasses and melt inclusions. The high F/Nd (up to 40) endmember is represented by HIMU melt inclusions and the low F/Nd (down to 14) by EM1 Pitcairn glasses. São Miguel melt inclusions have an intermediate F/Nd of 23.1±3.4.
We present a monochromatic sub-terahertz signal generation technique using an optical comb signal, arrayed waveguide gratings (AWGs), and a uni-traveling carrier photodiode (UTC-PD) for spectroscopic ...applications. This scheme offers random or continuous frequency tuning in the range between 100 GHz and up to 1 THz. In addition, since a RF synthesizer is employed as a reference signal source of the photonic frequency multiplier, frequency locking with external instruments and reliable operation are offered. Highly coherent optical comb signal for the photonic frequency multiplication provides a narrow linewidth and very low phase noise in the generated sub-terahertz signal. For 125 GHz, the phase noise is approximately -92 dBc/Hz at the offset frequency of 10 kHz. This is larger than that of the 25-GHz RF source by about 13 dB and agrees well with the theory regarding phase noise multiplications due to frequency multiplication. For generating monochromatic signals, unwanted spurious signals are suppressed in the optical domain over a wide range with two AWGs, and the suppression ratio is expected to be better than 46 dBc. Utilizing the implemented sub-terahertz signal generator with a J-band UTC-PD module, absorption lines of N 2 O were measured in the frequency range between 240 and 360 GHz and compared with theoretical calculations.
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