Electrical treatment of apple cossettes for intensifying juice pressing

The impact of two types of electrical treatment, electro‐osmotic (EO) and moderate electric field pulses (MEFP), on intensifying juice pressing from apple cossettes has been studied. The experiments were carried out in a laboratory filter‐press cell fitted with the appropriate electrical treatment system. Both EO and MEFP treatments result in a significant intensification of juice yield. Energy consumption, however, is 50–100 times less for MEFP treatment. Since a significant appearance of electrolytic processes and ohmic heating is observed with EO treatment, this treatment is very limited. MEFP treatment does not have these drawbacks and reduces the juice coloration. © 2000 Society of Chemical Industry     

Efficient and Reusable Pb(II) Metal–Organic Framework for Knoevenagel Condensation

A microporous lead–organic framework {[Pb₄(µ₈-MTB)₂(H₂O)₄]·5DMF·H₂O}_n (MTB?=?methanetetrabenzoate, DMF?=?N,N′-dimethylformamide) was synthesized and studied as a catalyst in Knoevenagel condensation reactions. The framework is built from tetranuclear [Pb₄(µ₃-COO)(µ₂-COO)₆(COO)(H₂O)₄] clusters and exhibits a 3D structure, with repeated 1D jar-like cavities with sizes about 14.98?×?7.88 and 14.98?×?13.17 Å² and BET specific surface area of 980 m² g^?1. To obtain open framework with unsaturated Pb(II) sites needed for catalysis, the thermal activation of the solvent exchanged sample was performed (DMF was exchanged by EtOH). The activated compound was tested in Knoevenagel condensation of bulky aldehydes and active methylene compounds at different temperatures. Excellent catalytic conversion and selectivity in condensation of small-sized aldehydes with malononitrile was observed, which indicates that the opened Pb(II) sites play a significant role in the heterogeneous catalytic process. Leaching test confirmed the stability of the catalyst in catalytic reactions. Moreover, the compound displayed good recyclability after several reuses without significant decrease in the original catalytic activity.

Graphical Abstract

Novel Pb(II) metal–organic framework was tested in Knoevenagel condensation. The catalyst showed excellent catalytic conversion, selectivity and recyclability. Aldehydes with lower kinetic diameter demonstrated high conversions and yields. Catalyst is less efficient for condensation of larger aromatic aldehydes.

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Experimental and thermodynamic modeling study of phase equilibria in the PbO–NiO–SiO2 system

An integrated experimental and thermodynamic modeling investigation of the phase equilibria in the PbO–NiO–SiO₂ system in air and also in equilibrium with liquid metal has been undertaken to better characterize the chemical reactions taking place in the Ni-containing Pb processing slags. New experimental phase equilibria data at 720°C–1740°C were obtained for this system using high-temperature equilibration of synthetic mixtures with predetermined compositions in sealed silica ampoules or in Au/Pt–Ir foils, a rapid quenching technique, and electron probe x-ray microanalysis of the equilibrated phase compositions. Phase equilibria and liquidus isotherms in the quartz/tridymite/cristobalite (SiO₂), olivine (Ni₂SiO₄), monoxide (NiO), Ni-barysilite (Pb₈NiSi₆O₂₁), massicot (PbO), and di-lead silicate (Pb₂SiO₄) primary phase fields were revealed and the extent of the high-SiO₂ two-liquid immiscibility gap in equilibrium with cristobalite was determined. New experimental data were used in the development of a thermodynamic database describing this ternary system. Also, modeling revision of the NiO–SiO₂ binary system was conducted, resulting in a smaller miscibility gap in ternary systems that was closer to the experimental results.     

GeSnOI mid-infrared laser technology

GeSn alloys are promising materials for CMOS-compatible mid-infrared lasers manufacturing. Indeed, Sn alloying and tensile strain can transform them into direct...     

Study on track dynamic forces due to rail short-wavelength dip defects using rail vehicle-track dynamics simulations

A rail vehicle-track interaction dynamics model has been applied to determine the track vertical dynamic forces due to rail shortwavelength dip defects such as squat, dip joints and welds, etc., which are required in both rail vehicle acceptance procedure and track maintenance. The model is validated using the field measurement data of rail squat defects and accelerations on a vehicle axlebox. The simulated track dynamic forces — the P₂ forces due to rail dipped joints have been compared with those calculated by using a well-known formula. The results are compared and the formula’s limitations have been discussed. The dependence of the track vertical dynamic forces on the rail dip defect size and vehicle speed has also been investigated.     

Investigation of influence of constraints with radius links on locomotive axle load distribution and wheelset steering ability

The problem of improving the tractive and dynamic performance of locomotives by means of using axle boxes with inclined radius links was investigated. The kinematics of axle boxes with different variants (different angles) and designs of inclined radius links, based on the vector contour method for link mechanisms, was studied. The results of a bogie design with vertically inclined radius links were used for the improvement of vertical load distribution for locomotives. The behavior of a locomotive running in a curve is more complicated because the lateral forces appear between a flange of the wheel and the head of the rail in the contact zone, and the values of wheel slip are higher than for straight sections of track. These two factors are the main reasons for wheel wear. Theoretical and experimental investigations to reduce wear and to improve vehicle dynamics were made, and the results obtained show that an effective solution can be reached by the use of inclined links to the longitudinal axis of a bogie in the horizontal plane. Questions about the development of a bogie with a radial installation and active steering are discussed.     

Problems,assumptions and solutions in locomotive design,traction and operational studies

Railway Engineering Science - Locomotive design is a highly complex task that requires the use of systems engineering that depends upon knowledge from a range of disciplines and is strongly...     

Compartmental residence time estimation in batch granulators using a colourimetric image analysis algorithm and Discrete Element Modelling

In this paper we present an experimental technique and a novel colourimetric image analysis algorithm to economically evaluate particle residence times within regions of batch granulators for use in compartmental population balance models. Residence times are extracted using a simple mixing model in conjunction with colourimetric data. The technique is applied to the mixing of wet coloured granules (binary and ternary systems) in a laboratory scale mixer. The resulting particle concentration evolutions were in qualitative agreement with those from the mixing model. It was seen that the algorithm was most stable in the case of the binary colour experiments. Lastly, simulations using the Discrete Element Method (DEM) were also performed to further validate the assumptions made in the analysis of the experimental results. Particle concentrations from the simulations showed the same trends as the experiment and highlighted the importance of particle size distributions on the DEM residence times.     

Nonmonotonic piezoresistive effect in elastomeric composite films

We compared the change of electrical resistance with elongation (piezoresistive effect) in thin films made of conductive multiwalled carbon nanotubes embedded in eight different elastomers. Two distinct forms of piezoresistive effect were observed: (i) in the “monotonic” (M) case, the film resistance always increased with the applied strain; (ii) the “nonmonotonic” (NM) case showed an initial increase in the resistance, while with further elongation the resistance began to decrease. By varying the amount of nitrile and/or styrene groups in the polymer matrix one can alter the piezoresistive effect qualitatively: composites with ～25 wt % or more of nitrile or styrene functional side groups exhibited M piezoresistance, while others, with no, or methyl side groups only, showed NM piezoresistance. Influence of the second filler (either conductive carbon black or nonconductive nanoclay) in the ternary composites on the piezoresistive effect was explored. The possibility to modify the piezoresistive behavior of the conductive elastomer composites, for example, via chemical modification of the polymeric matrix, opens up a new venue for practical applications such as diverse types of sensors and, in NM case, complex dynamical systems (bistable elements, electromechanical oscillators, etc.) in the MEMS field. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43518.