852 research outputs found

    Molecular characteristic of phosphoric acid treated soils

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    The expansive nature of soils containing high amounts of clay minerals can be altered through chemical stabilization, resulting in a material suitable for construction purposes. The primary objective of this investigation was to study the changes induced in the molecular structure of phosphoric acid stabilized bentonite and lateritic soil using Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared (FTIR) spectroscopy. Based on the obtained data, it was found that a surface alteration mechanism was the main reason responsible for the improvement of treated soils. Furthermore, the results indicated that the Al present in the octahedral layer of clay minerals were more amenable to chemical attacks and also partly responsible for the formation of new products

    RELATIONSHIP BETWEEN UNDERCARBOXYLATED OSTEOCALCIN AND OSTEOPROTEGERIN IN KNEE OSTEOARTHRITIS

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    Objective: The purpose of the present study was to evaluate the possible association between the serum levels of undercarboxylated osteocalcin (ucOC) and osteoprotegerin (OPG) in patients with knee osteoarthritis (OA). Methods: Twenty patients (10 men and 10 women) diagnosed to have knee OA, and twenty healthy subjects of matching age, sex, and BMI as a control group, were enrolled in this study. Serum levels of ucOC and OPG, were assayed using the corresponding human ELISA kits. Results: Patients with knee OA, showed a statistically significant elevation in serum levels of ucOC (P<0.001), and a statistically significant reduction in that of OPG (P<0.0001), as compared to the control group. Also, there is significant negative correlation (r=-0.554, p= 0.0113) between the serum levels of ucOC and OPG in knee OA patients. Conclusion: there is possible association between the serum levels of ucOC and OPG in patients with knee OA

    Thermal and Non-thermal Plasmas in the Galaxy Cluster 3C 129

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    We describe new Chandra spectroscopy data of the cluster which harbors the prototypical "head tail" radio galaxy 3C 129 and the weaker radio galaxy 3C 129.1. We combined the Chandra data with Very Large Array (VLA) radio data taken at 0.33, 5, and 8 GHz (archival data) and 1.4 GHz (new data). We also obtained new HI observations at the Dominion Radio Astrophysical Observatory (DRAO) to measure the neutral Hydrogen column density in the direction of the cluster with arcminute angular resolution. The Chandra observation reveals extended X-ray emission from the radio galaxy 3C 129.1 with a total luminosity of 1.5E+41 erg/s. The X-ray excess is resolved into an extended central source of ~2 arcsec (1 kpc) diameter and several point sources with an individual luminosity up to 2.1E+40 erg/s. In the case of the radio galaxy 3C 129, the Chandra observation shows, in addition to core and jet X-ray emission reported in an earlier paper, some evidence for extended, diffuse X-ray emission from a region east of the radio core. The 12 arcsec x 36 arcsec (6 kpc x 17 kpc) region lies "in front" of the radio core, in the same direction into which the radio galaxy is moving. We use the radio and X-ray data to study in detail the pressure balance between the non-thermal radio plasma and the thermal Intra Cluster Medium (ICM) along the tail of 3C 129 which extends over 15 arcmin (427 kpc). Depending on the assumed lower energy cutoff of the electron energy spectrum, the minimum pressure of the radio plasma lies a factor of between 10 and 40 below the ICM pressure for a large part of the tail. We discuss several possibilities to explain the apparent pressure mismatch.Comment: Accepted for publication in MNRAS. Refereed manuscript. 14 pages, 8 figures, additional panel of Fig. 3 shows asymmetric ICM distributio

    Probing Fine-Scale Ionospheric Structure with the Very Large Array Radio Telescope

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    High resolution (~1 arcminute) astronomical imaging at low frequency (below 150 MHz) has only recently become practical with the development of new calibration algorithms for removing ionospheric distortions. In addition to opening a new window in observational astronomy, the process of calibrating the ionospheric distortions also probes ionospheric structure in an unprecedented way. Here we explore one aspect of this new type of ionospheric measurement, the differential refraction of celestial source pairs as a function of their angular separation. This measurement probes variations in the spatial gradient of the line-of-sight total electron content (TEC) to 0.001 TECU/km accuracy over spatial scales of under 10 km to over 100 km. We use data from the VLA Low-frequency Sky Survey (VLSS; Cohen et al. 2007, AJ 134, 1245), a nearly complete 74 MHz survey of the entire sky visible to the Very Large Array (VLA) telescope in Socorro, New Mexico. These data comprise over 500 hours of observations, all calibrated in a standard way. While ionospheric spatial structure varies greatly from one observation to the next, when analyzed over hundreds of hours, statistical patterns become apparent. We present a detailed characterization of how the median differential refraction depends on source pair separation, elevation and time of day. We find that elevation effects are large, but geometrically predictable and can be "removed" analytically using a "thin-shell" model of the ionosphere. We find significantly greater ionospheric spatial variations during the day than at night. These diurnal variations appear to affect the larger angular scales to a greater degree indicating that they come from disturbances on relatively larger spatial scales (100s of km, rather than 10s of km).Comment: Accepted for publication by The Astronomical Journa

    Quantitative Studies of the Lung of the Domestic Fowl (Gallus gallus var. domesticus)

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    Comprehensive quantitiative studies on the lung of the domestic fow, (Gallus galluf var. domesticus). have been made. The data obtained were VL/W 14.65 ± 3.17 cm3/kg; Sa/W 18.08 ±2.51 cm2 /g; rht 0.322 ± 0.01 um; Dto/W 12. 79 ± 2.20 mlo/minlmmHglkg; dan DLo/W 1.39 ± 0.36 mlo/minlmmHglkg. These values are compared with those reported by other authors, and possible reasons for the differences are discussed. The mean values for many of the parameters have been calculated so that the values so obtained may form a basis for further investigations

    Synthesized and extending the Bidentate Schiff base complexes using multilayer feedforward neural network

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    Complexes of Pd(II) and Ni(II) have been synthesized with general composition ML2X2 (M =Pd(II), Ni(II); L = benzylsalicylideneimine and X = OCH3, F). All synthesized compoundshave been characterized using elemental analysis, magnetic susceptibility measurements,infrared and NMR spectral studies that led to the conclusion that the ligands act as bidentatemanner to form square planar geometry for all complexes. As an extending work, the modeldevelopment of these complexes using multilayer feedforward neural network wereperformed. NiL1d, PdL1d, NiL1c and PdL1c were fed to the training network as inputs andbacteria as output. Levenberg Marquardt training algorithm was used during the networktraining with 10 nodes in hidden layer. The results of testing network showed that theregression, R is 1, indicating that the developed model is good. This is supported by the small mean square error (MSE) is 1.948x10-28 at epochs 5. The finding in this study is significant, thus contributed to the design of antibacterial agent especially to the bidentate Schiff base complexes.Keywords: Schiff base, palladium(II), nickel(II), antibacterial, regression, neural network

    Response of suction distribution due to variations of permeability in residual soil slope

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    A landslide in residual soil normally occurs immediately after heavy rainfall. Previous studies have shown that decrease in matric suction during rainfall decreases the shear strength of soil and results in landslides. One of the factors that contribute to infiltration of water into soil is permeability of the soil which varies with depth. The variations of permeability can either prevent or allow water to infiltrate into deeper soil layer. Therefore, the aim of this study is to determine the suction distribution in a two-layered residual soil system with variable permeability function using laboratory physical slope model. The Ksat for Grade V varies from 5.11 × 10-4 m/s for relict joint of 100 mm spacing to 5.40 × 10-5 m/s for relict joint of 300 mm spacing. Meanwhile the Ksat for Grade VI represent Grade VI without burrow holes, 5.00 × 10-7 m/s and Ksat with burrow holes, 6.98 × 10-4 m/s. The infiltration tests were conducted for 12 series of experimental program. The suction distribution due to variations of permeability and rainfall intensity were determined. The results illustrated that suction distribution responded in various ways depending on permeability of the layered soil and also the rainfall intensity

    “Experimental and Theoretical Study of a Multi- Stage Solar Still Connected to Evacuated Solar Collector Tubes”

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    التقطير الشمسي أحد الحلول الفعالة والمفيدة لحل مشكلة شحة المياه النقية على سطح الارض. استعمل مقطر شمسي متعدد الطبقات وتم تحسين ادائه من خلال ربطه بانابيب مفرغة لتجميع الطاقة الشمسية. فكانت نسبة الزيادة بالانتاجية عن الانواع الاخرى بنسبة (38%). اجريت دراستان عملية ونظرية لحالتان الاولى كانت باحتواء خزانات المقطر الشمسي على الماء فقط من دون اي اضافة اما الحالة الاخرى فكانت باضافة ليف النخل الى حوض المرحلة الاولى. اضافة ليف النخل حسن من الانناجية الليلية للمقطر فكانت نسبة الزيادة في الانتاجية الليلية حوالي (25%) عما هو فارغ. يعتبر هذا النوع من المقطرات الشمسية تقنية حديثة في تحسين اداء المقطرات الشمسية متعددة الطبقات.Solar distillation is an effective and a useful method to solve the problem of water scarcity usable on the surface of the earth. A multi-stage solar still was used, and the performance of it was improved by linking it to (Evacuated Solar Collector Tubes), the rate of increase in productivity is about (38%). Practical and theoretical calculations were carried out on two cases. The first case was the basin of the first stage containing water only; the second case was the basin containing the fiber of the palm. When comparing the two cases there was a similarity between the two cases, but the addition of leaf fiber improved the increase in night productivity. The rate of increase in night productivity is about (25%).This type of solar still was a modern technology in improving the performance of multi-stage solar still
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