Stability of boreholes in a geologic medium including the effects of anisotropy

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｓｔｕｄｙｏｆｒｅｓｐｏｎｓｅｏｆａｂｏｒｅｈｏｌｅｔｏｃｈａｎｇｉｎｇｌｏａｄｉｎｇｃｏｎｄｉｔｉｏｎｓｉｓｏｆｐａｒｔｉｃｕｌａｒｉｎｔｅｒｅｓｔｔｏｅｖｅｒａｌｅｎｇｉｎｅｒｉｎｇｆｉｅｌｄｓｉｎｃｌｕｄｉｎｇｐｅ...     

Radioactivity in coral skeletons and marine sediments collected from the St. Martin’s Island of Bangladesh

Journal of Radioanalytical and Nuclear Chemistry - Although the coral island ‘St. Martin’s’ serves as the most attractive place for leisure and tourism, but no data on...     

Heterogeneous Heck reaction catalysed by silica gel-supported 1,2-diaminocyclohexane–Pd complex

A 1,2-diaminocyclohexane–Pd complex was immobilized onto the surface of silica gel and investigated as a catalyst for Heck coupling reactions. The immobilized catalyst exhibited high catalytic activity in the coupling of activated and nonactivated aryl substrates with various acrylates. Moreover, the catalyst was air-stable that could be recycled and reused without significant loss of catalytic activity.     

Perturbations of the periodicity of plant leaflet oscillations caused by visible light

Lateral leaflet movements in the presence of blue and white light stimuli in the plant Desmodium gyrans have been studied. A strong effect, namely, the reduction of amplitude of the lateral leaflet movement and thus a shortening period was observed. The oscillations regained their same regularity over a few cycles after the stimulus was removed and they quickly halted when the lateral leaflets were exposed to a light of higher intensity. However, the blue light was found to be more effective than the white light in the perturbation of leaflet oscillations. The results were discussed by reviewing the investigations performed in this plant with other stimuli.     

Biotransformation of perfumery terpenoids, ()- ambrox(R) by a fungal culture Macrophomina phaseolina and a plant cell suspension culture of Peganum harmala

ABSTRACT: BACKGROUND: Biotransformation offers chemo enzymatic system to modify the compounds into their novel analogues which are difficult to synthesize by chemical methods. This paper describes the biotransformational studies of ambrox, one of the most important components of natural Ambergris (wale sperm) with fungal and plant cell culture. RESULTS: Biotransformation of ()-ambrox (1) with a fungal cell culture of Macrophomina phaseolina and a plant cell suspension cultures of Peganum harmala yielded oxygenated products, 3beta- hydroxyambrox (2), 6beta-hydroxyambrox (3), 1alpha-hydroxy-3oxoambrox (4), 1alpha,3beta- dihydroxyambrox (5), 13,14,15,16-tetranorlabdane-3-oxo-8,12-diol (6), 3-oxoambrox (7), 2alpha- hydroxyambrox (8), 3beta-hydroxysclareolide (9), and 2alpha,3beta-dihydroxyambrox (10). Metabolite 4 was found to be new compound. These metabolites were structurally characterized on the basis of spectroscopic studies. CONCLUSION: Nine oxygenated metabolites of ()-ambrox (1) were obtained from Macrophomina phaseolina and Peganum harmala. Enzymatic system of screened organisms introduced hydroxyl and keto functionalities at various positions of compound 1 in a stereo- and regiocontrolled manner.     

Effective Separation and Simultaneous Quantification of Permethrin Isomers in Household Products by Validated TLC—Densitometric Method

JPC – Journal of Planar Chromatography – Modern TLC - Permethrin is widely used in household pests and insect-controlling products. A sensitive and robust TLC-densitometric method for...     

Photon energy dependence of the spin polarization

Spin polarization in semiconductors was investigated by pump-probe measurements, where the transmissions of the samples were monitored with probe pulses with same and opposite circular polarizations. The spin polarization as a function of the pump-probe delay was estimated, and the polarization was found to decay in a sub-ns timescale. It was also found that the polarization depends strongly on photon energy of the pump beam. The pumping energy dependence of the spin polarization was discussed based on the inter-band transition probabilities.     

Dynamic response of cable-stayed bridges to moving vehicles using the structural impedance method

The importance of dynamic interactions between cable-stayed bridges and heavy moving vehicles, such as trucks and locomotives, has been recognised by bridge engineers for a long time. A structural impedance algorithm is developed for analysing the dynamic response of cable-stayed bridges subjected to traversing vehicles. The bridge deck is modelled as an elastic plate, and the cables are idealised as springs for simplicity. The vehicles are modelled as a series of masses with suspension systems moving with different speeds and accelerations. A comprehensive computer program, CABLESIM, is developed for the static and dynamic analyses of a cable-stayed bridge. The accuracy of the numerical procedure and its computer implementation is verified with the available analytical and experimental results. A parametric study is conducted to investigate the effects of vehicle velocity, girder depth, different types of cable arrangements, and traffic load on the dynamic response of the deck. The numerical results are expected to be important in assessing the dynamics of cable-stayed bridge components and in determining the safety and allowable traffic conditions.     

Preparation and Characterization of Porous Titania by Modified Sol-Gel Method

Mesoporous titania, especially anatase, is attractive due to its potential applications. A novel method to control pore structure of titania, surfactant- or polymer modification, is proposed. The wet gels and gel films, prepared from Ti(O-nC₄H₉)₄ were dried at 90°C and annealed at 500°C after immersion in surfactant or polymer solutions, and mesoporous anatase was obtained. The pore size, pore volume and specific surface area of the surfactant-modified bulk gels, estimated from N₂ absorption-desorption curves, are more than twice larger than those of the gels without modification. The pore size of the surfactant-modified gel films, observed by SEM, are similar to that of the bulk gels. The pore size obviously depended on the size of micelles. The pore size of the gels modified with hydrophilic polymers hardly increased, but the pore volume and the specific surface area increased.