Phytoplankton responses to marine climate change – an introduction

Phytoplankton are one of the key players in the ocean and contribute approximately 50% to global primary production. They serve as the basis for marine food webs, drive chemical composition of the global atmosphere and thereby climate. Seasonal environmental changes and nutrient availability naturally influence phytoplankton species composition. Since the industrial era, anthropogenic climatic influences have increased noticeably – also within the ocean. Our changing climate, however, affects the composition of phytoplankton species composition on a long-term basis and requires the organisms to adapt to this changing environment, influencing micronutrient bioavailability and other biogeochemical parameters. At the same time, phytoplankton themselves can influence the climate with their responses to environmental changes. Due to its key role, phytoplankton has been of interest in marine sciences for quite some time and there are several methodical approaches implemented in oceanographic sciences. There are ongoing attempts to improve predictions and to close gaps in the understanding of this sensitive ecological system and its responses

Growth of a polarity controlled ZnO nanorod array on a glass/FTO substrate by chemical bath deposition

We present a polarity controlled ZnO nanorod thin film deposition on a glass substrate by Chemical Bath Deposition (CBD). The polarity of ZnO is controlled by the anions of the Zn-salt used in the deposition solution. In the presence of -SO42- the rods grow in the +c direction (Zn-polar), while -c directional (O-polar) growth is observed in the presence of -NO3-. The polarity of the nanorods is confirmed by the Convergent Beam Electron Diffraction (CBED) technique. This study depicts that rods with different polarity possess different optical, electrical and chemical properties

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Not AvailablePresent study was aimed at understanding the effect of pretreatments and modified atmosphere packaging on the quality of fresh-cut green bell pepper (Capsicum annuum L.) during low temperature storage. Dip treatment of freshly cut green bell pepper pieces in 2 % calcium propionate followed by surface drying and subsequent packing in cryovac PD961 film which maintained an equilibrium modified atmosphere of 13–14 % O2 and 7 % CO2 helped to extend the marketability till 9 days storage at 8 °C. The microbiological quality was at the best level up to 6 days of storage, as evidenced by a surge in aerobic plate count, pectinolysers and pseudomonads on subsequent days. Head space volatile analysis of the produce at regular intervals showed a reduction in monoterpenoids and simultaneous increase of aldehydes and ketones, sesquiterpenoids, esters, furans and pyrazines during storage. Principal component analysis of the head space volatiles identified, cis - ocimene, 1,3,8-paramenthatriene, trans 3- caren 2-ol, bergamotene, 2-hexenal, ethyl 1- decanol, (E)-3- hexenol and heptane thiol as the markers of freshness in minimally processed green bell pepper.t AvailableNot Availabl

In-situ phase transformation studies of Ni48Mn39In13 melt-spun ribbons

The phase transformation in Ni48Mn39In13 melt-spun ribbons has been studied by employing in-situ transmission electron microscopy (TEM) techniques. At room temperature, the investigations showed the martensite phase consisting of plates with internal stacking faults. This phase exhibited the presence of 7M and 5M modulations. In addition, a small volume fraction of the austenite phase was observed. Upon in-situ heating from room temperature to 95 degrees C, the martensite phase transformed to austenite phase. However, in the subsequent cooling-heating cycles, the martensite phase was retained at high temperature. We discuss our experimental observations and the possible mechanisms for the stabilization of the martensite phase due to thermal cycling. (c) 2012 Elsevier Ltd. All rights reserved

Raman Spectroscopy of the Charge Transfer Complex (TTF)x C60 Br8

We report Raman studies on powder samples of the charge transfer complex (TTF)(x)C60Br8 at room temperature. The phonons show considerable softening with respect to the frequencies observed in the Raman spectrum of solid C60Br8. The strongest mode at 1464 cm(-1) in C60Br8 is red shifted to a doublet with peaks at 1414 and 1421 cm(-1), implying an average phonon softening Delta omega of -47 cm(-1). A comparison with the phonon softening of the corresponding A(g)(2) mode in alkali-doped C-60 (Delta omega similar to -36 cm(-1) for A(6)C(60), A = K, Rb or Cs) suggests that 8 electrons are transferred per C60Br8 molecule in the charge transfer complex. The mode at 503 cm(-1) in C60Br8 is shifted upwards, similar to that in A(6)C(60) compounds

Raman study of the doped fullerene C60⋅TDAEC_{60}\cdot{TDAE}

Raman studies on powder samples of $C_{60}\cdot{TDAE}$ are reported in the temperature range of 296 to 14 K. The strongest line $A_g(2)$ shows a doublet at 1454 and 1463 $cm^{-1}$ whose relative intensities are strongly temperature dependent. The relative intensities of the $H_g(7)$ and $H_g(8)$ modes at 296 K are much higher than those in pure $C_{60}$ and these intensities increase at low temperatures. The phonon softening and broadening are compared with the results on alkali-doped $C_{60}$ and the theoretical calculations

Role of component layers in designing carbon nanotubes-based tandem absorber on metal substrates for solar thermal applications

Ti/Al2O3 coating was designed and developed for the growth of carbon nanotubes (CNTs)-based tandem absorber on stainless steel (SS) substrates. The aluminum and titanium target power densities and oxygen flow rates were optimized to deposit the Ti/Al2O3 coatings. The optimized Ti/Al2O3 coating with a Co catalyst on top was used as an underlying substrate to grow the CNT-based tandem absorber at 800 °C in Ar+H2 atmosphere (i.e., SS/Ti/Al2O3/Co/CNT). The formation of aluminum titanium oxide (AlTiO) was observed during the CNT growth process and this layer enhances the optical properties of the CNT based tandem absorber. At 0.36 µm CNT coating thickness, the tandem absorber exhibits an absorptance of 0.95 and an emittance of 0.20. The optical constants of Ti, Al2O3 and AlTiO coatings were measured using phase modulated spectroscopic ellipsometry in the wavelength range of 300–900 nm. The experimentally measured ellipsometric parameters have been fitted with the simulated spectra using Tauc-Lorentz model for generating the dispersion of the optical constants of the Al2O3 and the AlTiO layers. The Ti and Al2O3 layer thicknesses play a major role in designing CNT based tandem absorber with good optical properties. The transmission electron microscopy studies showed that the as-grown CNTs were multi-walled in nature. The angular and the polarization dependence studies of the CNT based tandem absorber grown at different thicknesses were carried out using UV-VIS-NIR spectrophotometer

Single-walled carbon nanotube bundles intercalated with semiconductor nanoparticles

Nanoparticles of CdSe, CdS and ZnSe have been incorporated in the inter-tubular gaps of single-walled carbon nanotube (SWNT) bundles. Electron microscope, X-ray diffraction (XRD), electronic spectroscopy and Raman studies have been employed to characterize these systems. The lengths of the intercalate inside the bundles could be varied by changing the reaction conditions. Electronic absorption and photoluminescence studies from the semiconductor intercalates show the expected blue-shift with respect to the corresponding bulk samples in CdS and ZnS samples. The SWNT lattice is expanded on incorporating CdSe as confirmed by XRD in the low-angle range. The expansion in the lattice is also corroborated by the Raman measurements which show a considerable red-shift for both the radial and the tangential modes of the SWNT signal, thus signifying an increase in the van der Waals gap between the tubes in the bundle. The red-shift of the Raman signal is due to the decrease in the inter-tube interactions as well as due to doping effects