Volume 17, Issue 3, 2017 July-September
| Volume 17, No 3 | Pages: |
| 2017 July-September | Articles: 6 |
Solvation enthalpy of uranium tetrachloride in aqueous-alcohols mixed solvents
The process of interaction between ions of a solute and the molecules of the solvent through relatively weak covalent bonds is called solvation. It involves evening out a concentration gradient and evenly distributing the solute molecules within the solvent. Hydration is a special case of solvation when the solvent molecules are water. Solvation energy, generally, is the energy released when ions in crystal lattices associate with molecules in a solvent, however it can be positive or negative, depending upon the combined effects of lattice and hydration energies in case of aqueous-ionic solid dissolution. Uranous chloride or uranium tetrachloride (UCl4) is a green crystalline solid which sublimes in vacuum at 500°C/10-3 mm. It is a Lewis acid and hence dissolves in solvents which can act as non-protic Lewis bases. Although dissolution of uranium tetrachloride crystals in water is an exothermic process yielding a green solution which is fairly stable in the cold, yet is hydrolyzed to a considerable extent to furnish an acidic reaction. Solvation enthalpies of quadrivalent uranium system have been scantly reported. The present communication deals with the calculation of enthalpy of solution of uranium tetrachloride in aqueous-non-aqueous solvent mixtures, particularly in 10 and 20 weight (wt) % methyl alcohol-water and ethyl alcohol-water systems at 25°C calorimetrically and thereby estimating the solvation enthalpy of UCl4 in the said media.
A geological study on Upper Bhuban Formation in parts of Surma Basin, Aizawl, Mizoram
Bubul Bharali , Pradip Borgohain, Devojit Bezbaruah, V. Vanthangliana, Parakh Protim Phukan, Raghupratim Rakshit
Tertiary sediments are thickly deposited in most part of the northeast India attaining a maximum thickness of ±7 km sedimentary succession. Surma basin located in the eastern proximity of India is also characterized by a thick sedimentary column which can be considered as the northeastern extension of Greater Bengal basin. This basin was initiated due to the mutual collision between Indian and Burmese Plate. Due to this collision, the bed rocks have undergone folding which are oriented N-S trending hill ranges. The basin was also cut by a number of parallel to sub-parallel transverse faults and thrusts. The litho association is consisting of sandstone, siltstone, shale and their various proportions. The present study focused on the provenance of the sediments, tectonic settings of the basin and various paleoclimatic conditions prevailing during the time of deposition by using petrography, granulometric and heavy mineral analysis of representative rock samples which were collected from various parts of Aizawl district of Mizoram belonging to the Upper Bhuban Formation. Based on the various proxies it was confirmed that the sediments were primarily derived from surrounding orogens and deposited in a shallow marine basin under the influence of fluvial-deltaic conditions which were basically sourced from felsic provenance. The sediments were moderately weathered under semi-humid to humid climatic condition before they deposited into Surma basin. Sandstones samples are litharenite and wacke type which were deposited in an active continental margin to recycled orogen settings.
Morphological and molecular characterization of Theloderma moloch (Anura: Rhacophoridae) from Indo-Burma biodiversity hotspot of northeast India
Samuel Lalronunga , C. Lalrinchhana
Specimens of a rare rhacophorid frog of the genus Theloderma were collected from Hmuifang, Mizoram, India. Based on their morphology and molecular analysis (16S rRNA), the specimens were identified as Theloderma moloch, a rare species previously recorded only from the Himalayan foothills of India and China. The present record significantly extends the known range of the species and is a first record for the state of Mizoram and Indo-Burma biodiversity hotspot. The uncorrected p-distance between the specimen from Mizoram, NE India and the specimen from Arunachal Pradesh, India (KU169993) and Tibet, China (KU243081) are 0.0% and 1.2% respectively.
Sporadic flowering of Bambusa tulda in Mizoram: A preliminary report
David C. Vanlalfakawma , F. Lalnunmawia, Sukanta Kumar Sen, S.K. Tripathi
Bambusa tulda Roxb. is a semi-deciduous caespitose bamboo endemic to Indo-Burma. It is known as ‘rawṭhing’ in Mizoram, India, and its mass gregarious flowering is called ṭhingtâm. ‘Ṭhingtâm’ has a cycle of about 45-50 years. The first ṭhingtâm, recorded in the region was in 1880, which was preceded by mautâm (gregarious flowering of Melocanna baccifera) in 1862; i.e., the ṭhingtâm phenomenon occurred ~20 years after the Mautâm. The last ṭhingtâm was recorded in 1981. However, there has been a localised ṭhingtâm at Zawlnuam, a village at the northwestern Mizoram. The first flowering was recorded in 2015. This unusual phenomenon needs to be investigated.
Assessment of potable water quality of surface water (tuikhur) and hand pumps in Siaha, southern Mizoram
The present study focused on the physico-chemical characterization of potable water from hand pump (groundwater) and sub-surface (tuikhur) water in Siaha, Mizoram, during pre-monsoon season of 2017. pH, total dissolved solids (TDS), electrical conductivity (EC), turbidity, total alkalinity (TA), total hardness (TH), iron (Fe), magnesium (Mg), calcium (Ca), nitrate (NO3), sulphate (SO4) and chloride (Cl) and their mean values obtained were 7.1, 67.72 mg/L, 103 mg/L, 1.8 NTU, 43.9 mg/L, 45 mg/L, 0.30 mg/L, 6.24 mg/L, 7.21 mg/L, 0.23 mg/L, 3.27 mg/L and 9.51 mg/L respectively. The results revealed that all these water samples were well within permissible limits established by World Health Organization (WHO), and Bureau of Indian Standards (BIS). Hence, they are suitable for drinking purposes. However, Iron contents at few sites are found exceeding the permissible value of 0.3 mg/L.
The path to the 2017 Nobel Prize in Physiology or Medicine
Jeffrey C. Hall, Michael Rosbash and Michael W. Young are selected to receive the 2017 Nobel Prize in Physiology or Medicine 2017 “for their discoveries of molecular mechanisms controlling the circadian rhythm”. They discovered clock genes and their protein-products that control the circadian rhythm in the fruit fly, Drosophila melanogaster. Starting with their work on the major clock gene period (per) in the 1980s, they subsequently discovered novel genes such as Clock, cry, cycle, dbt, pdp1, per, tim, vri, and their mutations that affect the fruit fly daily behaviours. With the proteins these genes produce, their discoveries have established the understanding of a complex molecular network of clock genes and proteins. This comprehensive knowledge further enrich our perception of circadian rhythm in other animals, including us. Behind this knowledge is the foundation of understanding of many disease and health-related issues concerned with our genetics, hormones, and behaviour. Their discoveries are befitting of the Nobel Prize, but it is a bit of an irony that the pioneer discovers have already died and will forever be denied of their deservedly fame. The epoch-making discovery of per gene was in fact by Seymour Benzer and his student Ronald J. Konopka discovered in 1971. Konopka especially continued as one of the leading scientists, in many of the later discoveries. But life and luck for Nobel fame ran out for them.
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