Catalytic dehydration of cassava-derived glucose into 5-hydroxymethyl-furan (5-HMF) in 1-butyl-3- methylimidazolium chloride ([BMIM]Cl)

Catalytic dehydration of glucose and fructose into 5- Hydroxymethylfuran (5-HMF) catalysed by sulfated zirconia in 1- butyl-3-methylimidazolium chloride ([BMIM][Cl]) ionic liquid was investigated by reactive vacuum distillation process. A 5-HMF yields of 82% and 65% were obtained using fructose and glucose substrates in 2 h reaction time at 180 oC. When the reaction time was increased beyond 2 h, a decreased in 5-HMF yield was observed. The ionic liquid and sulfated zirconia exhibited a constant activity when recycled for five successive trials. This process provided an avenue whereby the production of 5-HMF from cassava-derived carbohydrate is conducted and separated with minimal use of volatile solvents.Keywords: Cassava, 5-Hydroxymethylfuran, reactive vacuum distillatio

An Origin-of-Life Reactor to Simulate Alkaline Hydrothermal Vents

Chemiosmotic coupling is universal: practically all cells harness electrochemical proton gradients across membranes to drive ATP synthesis, powering biochemistry. Autotrophic cells, including phototrophs and chemolithotrophs, also use proton gradients to power carbon fixation directly. The universality of chemiosmotic coupling suggests that it arose very early in evolution, but its origins are obscure. Alkaline hydrothermal systems sustain natural proton gradients across the thin inorganic barriers of interconnected micropores within deep-sea vents. In Hadean oceans, these inorganic barriers should have contained catalytic Fe(Ni)S minerals similar in structure to cofactors in modern metabolic enzymes, suggesting a possible abiotic origin of chemiosmotic coupling. The continuous supply of H2 and CO2 from vent fluids and early oceans, respectively, offers further parallels with the biochemistry of ancient autotrophic cells, notably the acetyl CoA pathway in archaea and bacteria. However, the precise mechanisms by which natural proton gradients, H2, CO2 and metal sulphides could have driven organic synthesis are uncertain, and theoretical ideas lack empirical support. We have built a simple electrochemical reactor to simulate conditions in alkaline hydrothermal vents, allowing investigation of the possibility that abiotic vent chemistry could prefigure the origins of biochemistry. We discuss the construction and testing of the reactor, describing the precipitation of thin-walled, inorganic structures containing nickel-doped mackinawite, a catalytic Fe(Ni)S mineral, under prebiotic ocean conditions. These simulated vent structures appear to generate low yields of simple organics. Synthetic microporous matrices can concentrate organics by thermophoresis over several orders of magnitude under continuous open-flow vent conditions

Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

Peer reviewe

Charged-particle nuclear modification factors in PbPb and pPb collisions at √=sNN=5.02 TeV

The spectra of charged particles produced within the pseudorapidity window |η| < 1 at √ sNN = 5.02 TeV are measured using 404 µb −1 of PbPb and 27.4 pb−1 of pp data collected by the CMS detector at the LHC in 2015. The spectra are presented over the transverse momentum ranges spanning 0.5 < pT < 400 GeV in pp and 0.7 < pT < 400 GeV in PbPb collisions. The corresponding nuclear modification factor, RAA, is measured in bins of collision centrality. The RAA in the 5% most central collisions shows a maximal suppression by a factor of 7–8 in the pT region of 6–9 GeV. This dip is followed by an increase, which continues up to the highest pT measured, and approaches unity in the vicinity of pT = 200 GeV. The RAA is compared to theoretical predictions and earlier experimental results at lower collision energies. The newly measured pp spectrum is combined with the pPb spectrum previously published by the CMS collaboration to construct the pPb nuclear modification factor, RpA, up to 120 GeV. For pT > 20 GeV, RpA exhibits weak momentum dependence and shows a moderate enhancement above unity

Extrusion pressure generated in high alumina content paste extrusion

Four different alumina pastes with various solvent volume fractions were processed by extrusion free forming and the pressures generated in the extrusion process were recorded and analyzed. The extrusion pressure increased as the solvent volume fraction decreased. Air bubbles and particle agglomeration influenced the final properties of the product and caused pressure to fluctuate. An aging process for the paste was introduced to obtain more even solvent distribution and hence deliver highly regular ceramic lattice structure

Mechanical properties of injection moulding suspensions as a function of ceramic volume fraction and temperature

The elastic modulus of ceramic injection moulding compositions with ceramic volume fractions from 0 to 0·56 were measured in the temperature range from 20°C to the softening point of 144°C. The uniaxial fracture strength of the most concentrated suspension was measured in the same temperature range. Poisson's ratio was obtained by a train gauge method in which the electrical heating effect of the gauge was controlled. The results are compared with model predictions in order that such data can be obtained for diverse suspensions from a minimum of measurements. Such results are necessary for the analysis of residual stress and hence cracking during the solidification stage of ceramic injection moulding. © 1991

The properties of a ceramic injection moulding suspensions based on a preceramic polymer

A ceramic suspension incorporating fine sinterable silicon carbide powder in a polycarbosilane vehicle has been modified by additions of paraffin wax to make it suitable for plastic forming operations. The diluent enables higher volume fractions of ceramic to be incorporated and lowers the softening point of the suspension. The danger of temperature-induced crosslinking in processing machinery is alleviated. © 1991

Computation of volume flow in modulated pressure ceramic injection moulding

The volume of ceramic suspension involved in oscillatory flow through the sprue and runners during modulated hold pressure moulding was calculated using the cooling characteristics of the moulding and the equation of state for the suspension. With single-gated moulds, the displaced volume is limited by the mould dimensions and the compressibility of the suspension. This restricts the heat dissipated from viscous losses in the core of the sprue and hence the extension to sprue solidification time. The calculation facilitates preliminary estimations of heat fluxes. © 1993