Measurements of Dendritic Growth Velocities in Undercooled Melts of Pure Nickel Under Static Magnetic Fields

Dendritic growth velocities in undercooled melts of pure Ni have been intensively studied over the past fifty years. However, the literature data are at marked variance with the prediction of the widely accepted model for rapid dendritic growth both at small and at large undercoolings. In the present work, bulk melts of pure Ni samples of high purity were undercooled by glass fluxing treatment under a static magnetic field. The recalescence processes of the samples at different undercoolings were recorded using a high-speed camera, and were modeled using a software to determine the dendritic growth velocities. The present data confirmed the effect of melt flow on dendritic growth velocities at undercoolings below 100 K. A comparison of the present data with previous measurements on a lower purity material suggested an effect of impurities on dendritic growth velocities at undercoolings larger than 200 K as well

Ethylene Response of Plum ACC Synthase 1 (ACS1) Promoter is Mediated through the Binding Site of Abscisic Acid Insensitive 5 (ABI5).

The enzyme 1-amino-cyclopropane-1-carboxylic acid synthase (ACS) participates in the ethylene biosynthesis pathways and it is tightly regulated transcriptionally and post-translationally. Notwithstanding its major role in climacteric fruit ripening, the transcriptional regulation of ACS during ripening is not fully understood. We studied fruit ripening in two Japanese plum cultivars, the climacteric Santa Rosa (SR) and its non-climacteric bud sport mutant, Sweet Miriam (SM). As the two cultivars show considerable difference in ACS expression, they provide a good system for the study of the transcriptional regulation of the gene. To investigate the differential transcriptional regulation of ACS1 genes in the SR and SM, their promoter region, which showed only minor sequence differences, was isolated and used to identify the binding of transcription factors interacting with specific ACS1 cis-acting elements. Three transcription factors (TFs), abscisic acid-insensitive 5 (ABI5), GLABRA 2 (GL2), and TCP2, showed specific binding to the ACS1 promoter. Synthetic DNA fragments containing multiple cis-acting elements of these TFs fused to β-glucuronidase (GUS), showed the ABI5 binding site mediated ethylene and abscisic acid (ABA) responses of the promoter. While TCP2 and GL2 showed constant and similar expression levels in SM and SR fruit during ripening, ABI5 expression in SM fruits was lower than in SR fruits during advanced fruit ripening states. Overall, the work demonstrates the complex transcriptional regulation of ACS1

Integral techno-economic comparison and greenhouse gas balances of different production routes of aromatics from biomass with CO₂ capture

The techno-economic performance and CO2 equivalent (CO2eq) reduction potential of bio-based aromatic production cases with and without CO2 capture and storage (CCS) have been evaluated and compared to those of fossil-based aromatic production. The bio-cases include tail gas reactive pyrolysis (TGRP), catalytic pyrolysis (CP), hydrothermal liquefaction (HTL), gasification-methanol-aromatics (GMA), and Diels-Alder of furan/furfural combined with catalytic pyrolysis of lignin (FFCA). The crude oil-based naphtha catalytic reforming (NACR) routes have GHG emissions of 43.4 and 43.9 t CO2eq/t aromatics with and without CCS (NACR-CCS), respectively. Except for HTL, all the biomass cases with CCS show negative emissions between −6.1 and −1.1 t CO2eq/t aromatics with avoidance costs ranging from 27.7 to 93.3 $/t CO2eq. Under favorable conditions, GMA with CCS (GMA-CCS) has the lowest emissions (−14.6 t CO2eq/t aromatics), while CP with CCS (CP-CCS) shows the lowest avoidance cost (12.3$/t CO2eq). All biomass based aromatics production techniques are currently at the laboratory or demonstration stages, except for CP, which has pilot plants. The results indicate that bio-based aromatics production, with their reasonable avoidance costs and low, or potentially negative, greenhouse gas (GHG) emissions, are an attractive option to compensate for the expected aromatic production shortages in the coming decades