Lingulodinium machaerophorum expansion over the last centuries in the Caspian Sea reflects global warming

This article is made available through the Brunel Open Access Publishing Fund. Copyright @ Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 License.We analysed dinoflagellate cyst assemblages in four short sediment cores, two of them dated by radionuclides, taken in the south basin of the Caspian Sea. The interpretation of the four sequences is supported by a collection of 27 lagoonal or marine surface sediment samples. A sharp increase in the biomass of the dinocyst occurs after 1967, especially owing to Lingulodinium machaerophorum. Considering nine other cores covering parts or the whole of Holocene, this species started to develop in the Caspian Sea only during the last three millennia. By analysing instrumental data and collating existing reconstructions of sea level changes over the last few millennia, we show that the main forcing of the increase of L. machaerophorum percentages and of the recent dinocyst abundance is global climate change, especially sea surface temperature increase. Sea level fluctuations likely have a minor impact. We argue that the Caspian Sea has entered the Anthropocene

Optical surface waves on one-dimensional photonic crystals: investigation of loss mechanisms and demonstration of centimeter-scale propagation

It has been predicted that optical surface waves at interfaces that separate purely dielectric media should be able to propagate over long distances, particularly over distances greater than possible with surface plasmon polaritons. Despite numerous studies, there has been no report of such an observation, and an estimate of the propagation length achievable with dielectric optical surface waves is yet to be provided. In this work, we focus on the propagation properties of optical modes supported at the free surface of a one-dimensional photonic crystal. The contributions of intrinsic and extrinsic loss mechanisms are discussed. The developed understanding is applied to the design of structures that are optimized to support long propagating optical surface waves. We experimentally demonstrate, for the first time, the existence of optical surface waves capable of propagating over centimeter-scale distances in the visible spectral range. This result opens new perspectives for the use of optical surface waves in integrated optics and for light-matter interactions at interfaces.Comment: 11 pages, 4 figure

CO₂ gasification of bio-char derived from conventional and microwave pyrolysis

Thermal-chemical processing of biomass is expected to provide renewable and clean energy and fuels in the future. Due to the nature of endothermic reactions, microwave and conventional heating have been applied to this technology. However, more studies need to be carried out to clarify the difference between these two heating technologies. In this work, we investigated two bio-char samples produced from conventional pyrolysis of wood biomass (yield of bio-char: 38.48 and 59.70 wt.%, respectively) and one bio-char produced from microwave pyrolysis with a yield of 45.16 wt.% from the same biomass sample at different process conditions. Various methodologies have been used to characterise the bio-chars. CO₂ gasification of bio-char has also been studied using a thermogravimetric analyser (TGA) and a fixed-bed reaction system. The results show that volatile and carbon contents of the bio-char derived from microwave pyrolysis were between the two conventional bio-chars. However, the microwave bio-char is more reactive for CO₂ gasification, as more CO was released during TGA experiments, and the CO release peak was narrower compared with the CO₂ gasification of the conventional bio-chars. It is suggested that the conventional bio-char is less reactive due to the presence of more secondary chars which are produced from secondary reactions of volatiles during the conventional biomass pyrolysis. While the microwave pyrolysis generates more uniform bio-chars with less secondary char, and therefore, has advantages of producing bio-char for downstream char gasification

Cynara cardunculus L. gasification in a bubbling fluidized bed: the effect of magnesite and olivine on product gas, tar and gasification performance

peer-reviewedGasification of Cynara cardunculus L. was performed in a bubbling fluidized bed (BFB) using air as gasifying agent and, magnesite and olivine as different bed materials. Temperature was varied during the experiments (700-800 degrees C) with fixed biomass feeding and air flow rate. The effect of using the magnesite and olivine on gas and tar composition, carbon and biomass conversion, and cold gas efficiency was investigated. The product gas showed high hydrogen content (13-16% v/v) for both magnesite and olivine in the studied temperature range. Higher heating value and gas yield were improved with increasing the temperature from 700 to 800 degrees C. Biomass and carbon conversion were greater than 75%, obtaining values higher than 90% for both 700 and 800 degrees C in magnesite and for 800 degrees C in olivine. Small differences in total tar were observed between materials, although tar composition was very different. BTEX were higher for olivine and similar PAHs was obtained for both magnesite and olivine. A higher catalytic activity at 800 degrees C was observed for magnesite. Gasification performance was better with magnesite at 700 degrees C while olivine showed better properties at 800 degrees C. (C) 2016 Elsevier Ltd. All rights reserved.ACCEPTEDpeer-reviewe

Response of Wheat Genotypes to Terminal Drought Stress Using Physiological Indices

In order to study the effect of terminal drought stress on yield and yield components and some physiological traits of wheat genotypes, a field experiment was conducted at the Research Farm of Agricultural College of Shiraz University during 2010-11 growing season in a split plot arrangement based on randomized complete block design with three replications. Main plots were assigned to irrigation treatment and the sub plots to sixteen wheat genotypes. Post anthesis cutting irrigation caused significant reduction in grain yield (GY), biological yield (BY), harvest index (HI), canopy temperature depression (CTD), grain number per spike, 1000 grain weight and relative water content (RWC). Under normal irrigation conditions, the highest grain yield was obtained from Zarrin cultivar, whereas, under drought stress conditions, the highest grain yield was obtained from Tabasi cultivar. The trait most sensitive to water stress was grain yield (mean reduction 51.6% compared to control) followed by harvest index (mean reduction 37.2% compared to control). Correlation coefficient results showed that under normal irrigation conditions the highest correlation was between grain yield and biological yield (0.844*) and under stress conditions was found between grain yield and grain number per spike (0.895**), CTD (0.771**) and 1000 Grain weight (0.689**). Evaluating of CTD trend under stress conditions showed that by passing time from applying cutting irrigation, canopy temperature (CT) gradually increases due to water unavailability. The most reduction in grain and biological yield under drought stress was observed in C-85-7 genotype, whereas, cv. Shiraz with the least reduction in these two components, was found a drought tolerant and yield stability cultivar. At both irrigation treatments, there was a positive correlation between grain yield and CTD therefore, CTD may be a suitable index for selecting late-season water stress tolerant wheat cultivars