Virtual mass of an oscillating sphere within a fixed concentric shell

CER62AA84.July 30, 1962.Includes bibliographical references.The virtual mass of a sphere oscillating within a fixed concentric spherical shell filled with water was determined experimentally for seven sphere-to-shell diameter ratios between 0 and 0.865. Laboratory measurements of the virtual mass for diameter ratios less than 0.520 agreed closely with the theoretically predicted values based on a potential flow analysis. For ratios greater than 0.520 the virtual mass increased more rapidly than the potential flow theory indicated with an increase of 33% for a diameter ratio of 0.865

<Notes>Distribution of Monthly Rainfall in Northeast Thailand

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。The distribution in space and in time of monthly rainfall in Northeast Thailand is investigated in this paper, using daily data at 56 stations, each having at least 20 years of continuous record. It was found that monthly rainfall sequences at all stations in this region have six significant harmonics corresponding to six periods : 12,6,4,3,2.4 and 2 months. At a station, the rainfall sequence in a month can be considered to be independent and can be fitted by the leakage law. Moreover, during the months of April through September, monthly rainfall in the region has a general pattern of increasing values towards the eastern and northeastern sections, while during the months of October to January, it has a general pattern of decreasing values towards these sections. Finally, an assessment of water availability for irrigation is made using the distribution of monthly rainfall and the potential evapotranspiration

Activity-Guided Isolation of Antioxidant Compounds from &lt;em&gt;Rhizophora apiculata&lt;/em&gt;

&lt;em&gt;Rhizophora apiculata&lt;/em&gt; (&lt;em&gt;R. apiculata&lt;/em&gt;) contains an abundance of biologically active compounds due its special salt-tolerant living surroundings. In this study, the total phenolic content and antioxidant activities of various extract and fractions of stem of &lt;em&gt;R. apiculata&lt;/em&gt; were investigated. Results indicated that butanol fraction possesses the highest total phenolic content (181.84 mg/g GAE/g dry extract) with strongest antioxidant abilities. Following &lt;em&gt;in vitro&lt;/em&gt; antioxidant activity-guided phytochemical separation procedures, lyoniresinol-3α-&lt;em&gt;O&lt;/em&gt;-β-arabinopyranoside (&lt;strong&gt;1&lt;/strong&gt;), lyoniresinol-3α-&lt;em&gt;O&lt;/em&gt;-β-rhamnoside (&lt;strong&gt;2&lt;/strong&gt;), and afzelechin-3-&lt;em&gt;O&lt;/em&gt;-L-rhamno-pyranoside (&lt;strong&gt;3&lt;/strong&gt;) were separated from the butanol fraction. These compounds showed more noticeable antioxidant activity than a BHT standard in the DPPH, ABTS and hydroxyl radical scavenging assays. HPLC analysis results showed that among different plant parts, the highest content of &lt;strong&gt;1&lt;/strong&gt;–&lt;strong&gt;3&lt;/strong&gt; was located in the bark (0.068%, 0.066% and 0.011%, respectively). The results imply that the &lt;em&gt;R. apiculata&lt;/em&gt; might be a potential source of natural antioxidants and &lt;strong&gt;1&lt;/strong&gt;–&lt;strong&gt;3&lt;/strong&gt; are antioxidant ingredients in &lt;em&gt;R. apiculata&lt;/em&gt;