Transhydrogenation of propyne with butane over a vanadia/θ-alumina catalyst

The transhydrogenation of propyne and butane was studied over a 1 % VO x /alumina catalyst at 873 K. In the absence of the vanadia, the alumina support was active for cracking and alkylation. However, the addition of the vanadia reduced the propensity for both cracking and alkylation and added dehydrogenation activity. When propyne and butane were co-fed over the catalyst there was a synergistic effect resulting in an increased conversion of propyne (81 cf. 26 % when fed alone); however, much of this increased conversion was converted to carbon deposited on the catalyst. Transhydrogenation of propyne to propene was detected with an enhanced yield of propene when the propane/butane mix was passed over the catalyst. Taking a yield based on propyne fed then the yield of propene increased from 1.2 to 5.0 %. The conversion of butane to value-added products was also enhanced with all the butane converted accounted for in the production of 1-butene, trans-2-butene, iso-butane and iso-butene

Floral development and potential pollinators of Syzygium myhendrae (Bedd. ex Brandis) Gamble, a wild endemic tree of the Southern Western Ghats, India

Syzygium myhendrae, is a semi-evergreen, endemic and endangered tree species of the Southern Western Ghats, India which exhibits bi-annual mode of flowering and fruiting behaviour. This research is specifically aimed to observe the sequence of morphological processes occurring during floral development and to identify the potential pollinators from the different floral visitors. These aims are achieved by examining the individual trees of candidate species during their flowering season. Sticky traps, bee bowls, sweep nets and pan traps were used to capture floral visitors at the anthesis stage. Visitation frequency and visitor activity index were calculated to distinguish effective pollinators from visitor insects. The results showed nine stages in flower development starting from flower bud emergence to fruit ripening, which took 6-9 weeks. Nine species of insects were recorded as visitors. Honey bees (Apis cerana, ApisMdorsata and Tetragonula iridipennis), butterflies (Hypolimnas misippus,pachilopta pandiana), wasp species, beetle species, fly species were exclusively visiting the flowers of the candidate species. Among the honey bees, Apis dorsata showed high visitation frequency (0.40±0.01) followed by Apis cerana (0.31±0.02) and Tetragonula iridipennis (052±0.02). As per the visitation frequency, it can be concluded that Apis dorsata was the most frequent and effective pollinator

PHYTOCHEMICAL ANALYSIS AND IN VITRO DPPH ASSAY OF ETHANOLIC EXTRACT OF MUCUNA PRURIENS SEED

Objective: To detect the bioactive phytoconstituents of Mucuna pruriens seed extract and to estimate invitro antioxidant activity. Methods: Preliminary phytochemical analysis were done to determine the active phytochemical constituents and DPPH (2, 2-diphenyl-1-picrylhydrazyl) assay method was used for the estimation of In vitro antioxidant activity. Results: Preliminary phytochemical analysis of Mucuna pruriens seed extract showed the presence of chief bioactive components like phenols, flavonoids, tannins, alkaloids, triterpenes and phytosterols. In antioxidant assay, Mucuna pruriens seed extract exhibited a maximum DPPH radical scavenging activity of 72.95% against the standard control with a maximum activity of 93.24% for the same concentration (0.2 mg/ml). This is a clear indication of strong antioxidant property of the drug. Conclusion: Mucuna Pruriens seeds are abundant source of natural antioxidants, and important bioactive phytoconstituents

Gynostemium morphology and floral biology of Thottea duchartrei Sivar., A.Babu & Balach. (Aristolochiaceae), an endemic species from Western Ghats, India

Gynostemium is a putative floral structure formed by the fusion of the male and female reproductive parts (stamens and carpels) through a process during its development called synorganization. Most of the Indian species of Thottea Rottb. have a prominent gynostemium in their floral architecture, with varying degrees of adnation and complexity. Even though the gynostemium is a significant taxonomic marker for the inter-specific systematics in Thottea, the scepticism and arguments on deciphering its morphology and functional parameters, including the existence of staminodes, makes it imperative to be examined in detail. The present study is the first attempt in this line which aims to explore the morphological characters of gynostemium and reproductive biology of Thottea duchartrei Sivar., A.Babu and Balach., an endemic species in the Western Ghats. Stereo zoom microscopy, SEM and reproductive biological studies were conducted providing special emphasis to the gynostemium. Detailed analysis revealed the structural and functional diversity of gynostemium with regard to its components. The study also helped to recognize the columnar outgrowths on the gynostemium as staminodes. In total, the present study helps to solve the confusions regarding the functional identity of the gynostemium T. duchartrei with regard to its morphology

A two dimensional model for ferromagnetic martensites

We consider a recently introduced 2-D square-to-rectangle martensite model that explains several unusual features of martensites to study ferromagnetic martensites. The strain order parameter is coupled to the magnetic order parameter through a 4-state clock model. Studies are carried out for several combinations of the ordering of the Curie temperatures of the austenite and martensite phases and, the martensite transformation temperature. We find that the orientation of the magnetic order which generally points along the short axis of the rectangular variant, changes as one crosses the twin or the martensite-austenite interface. The model shows the possibility of a subtle interplay between the growth of strain and magnetic order parameters as the temperature is decreased. In some cases, this leads to qualitatively different magnetization curves from those predicted by earlier mean field models. Further, we find that strain morphology can be substantially altered by the magnetic order. We have also studied the dynamic hysteresis behavior. The corresponding dissipation during the forward and reverse cycles has features similar to the Barkhausen's noise.Comment: 9 pages, 11 figure

Low energy excitations in crystalline perovskite oxides: Evidence from noise experiments

In this paper we report measurements of 1/f noise in a crystalline metallic oxide with perovskite structure down to 4.2K. The results show existence of localized excitations with average activation energy $\approx$ 70-80 meV which produce peak in the noise at T $\approx$ 35-40K. In addition, it shows clear evidence of tunnelling type two-level-systems (as in glasses) which show up in noise measurements below 30K.Comment: 11 pages, 4 figures, to appear in Phys Rev B, vol 58, 1st Dec issu

Optimization of admixture and three-layer particleboard made from oil palm empty fruit bunch and rubberwood clones

Empty fruit bunch (EFB) is a biomass that is widely available and has the potential to be used as industrial raw material especially in wood-based industries. This study focuses on producing a particleboard by incorporating EFB with two different rubberwood clones: Prang Besar (PB) 260 and RRIM 2002, respectively. PB 260 is a commercially planted clone and wood from matured (>25 year-old) trees are used by wood-based panel manufacturers. RRIM 2002 is a new clone planted at the Malaysian Rubber Board (MRB) research trial plots and consists of only 4-year-old trees. Two types of particleboards (admixture and three-layer) with different ratios were produced. The Japanese Industrial Standard (JIS-5908 2003 particleboard) was used to evaluate mechanical and dimensional stability properties of the particleboards. From the study, it was found that admixture particleboards showed superior properties compared to three-layer particleboards. Layering EFB and rubberwood significantly decreased board performance for all properties (except internal bonding). The optimum ratios of EFB and both rubberwood clones are found to be 1:1 (50% EFB: 50% rubberwood). Meanwhile, increasing the rubberwood clones ratio to 70% lowered board performance especially for EFB (30%):RRIM 2002 clone (70%) boards which showed the lowest values for all properties for both admixture and three-layer board