Shear Cell Technique Research Articles

Prediction of Temperature Dependence of Impurity Diffusion Coefficients in Liquid Metal Based on a Hard-Sphere Model from Measurements Using Shear Cell Technique and Stable Density Layering

Prediction of Temperature Dependence of Impurity Diffusion Coefficients in Liquid Metal Based on a Hard-Sphere Model from Measurements Using Shear Cell Technique and Stable Density Layering

Suppressing Natural Convection for Self-diffusion Measurement in Liquid Pb Using Shear Cell Technique by Stable Density Layering of Isotopic Concentration

Suppressing Natural Convection for Self-diffusion Measurement in Liquid Pb Using Shear Cell Technique by Stable Density Layering of Isotopic Concentration

A review of research on plant-based meat alternatives: Driving forces, history, manufacturing, and consumer attitudes.

The topic of plant-based meat alternatives (PBMAs) has been discussed for several decades, but it has only recently become one of the hottest topics in the food and research communities. With the purpose of investigating the current situation of scientific research on PBMA and determining future research opportunities, the driving forces for PBMA development, a brief history of its progression, key technologies required for production, and the resulting consumer attitudes are summarized. Environmental, human health, and animal welfare concerns are the main factors that have driven the development of PBMA. Although its history can trace back to ancient Asian civilizations, the first generation of PBMA originated in 1960s and a new generation of PBMA designed for carnivore was developed in recently years. Structuring methods such as extrusion and shear cell techniques have been widely studied, but improvements toward the overall appearance and flavor, biological and chemical safety control, as well as the selection of protein sources are also very important for PBMA production. The consumer acceptance of PBMA remains unsatisfactory but is continually improving. Based on those knowledge, future research opportunities include developing more effective strategies for consumer education, providing more scientific evidence for the health properties of PBMA, finding more suitable protein sources to improve the quality of the final products, improving the appearance and flavor, further examining and securing the chemical safety, exploring the structure formation mechanism during the extraction or shearing processes, and developing methods and standards for a quality evaluation of PBMA.

Investigation of powder flowability at low stresses: Influence of particle size and size distribution

At moderate stresses, shear cells are the preferred method of powder flow measurement. However, several industrial processes operate at low stresses, where the determination of unconfined yield strength by the shear cell technique may be inconsistent, or found not to correlate with observed behaviour. Alternatively, ball indentation can be used, which directly measures hardness; related to unconfined yield strength by the constraint factor. However, it is not known how constraint factor is influenced by particle properties. Here, ball indentation and shear cell methods are applied for glass beads of various size distributions, and the influence of particle size distribution on the constraint factor is explored. The constraint factor is shown to be independent of the pre-consolidation stress, though reduces as the d10, d50 or d90 are increased. Unconfined yield strength inferred from indentation measurements suggest that extrapolation of shear cell data to low stresses overestimates the unconfined yield strength.

Investigation of the Influence of Different Solute on Impurity Diffusion in Liquid Sn using the Shear Cell Technique

Investigation of the Influence of Different Solute on Impurity Diffusion in Liquid Sn using the Shear Cell Technique

Concentration dependence of interdiffusion in aluminum-rich Al-Cu melts

We present measurements and ab initio molecular dynamic simulations of interdiffusion in aluminum-rich Al-Cu melts for concentrations up to 30 at. % copper. To obtain accurate data, a combination of x-ray radiography and shear-cell technique is used, including an experiment in microgravity. Interdiffusion coefficients between 5.3 and $3.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}\phantom{\rule{4pt}{0ex}}{\mathrm{m}}^{2}/\mathrm{s}$ at 973 K are found experimentally with a slight decrease with increasing Cu concentration. Results from ab initio molecular dynamic simulation at 1000 K show a decrease of interdiffusion coefficients with the same slope at slightly higher values. Using Darken's equation to discuss the relation between self-diffusion and interdiffusion, we find the cross-correlation term $S$ to be around unity by simulation and experiment.

Self-diffusion Measurements of Liquid Sn Using the Shear Cell Technique and Stable Density Layering

By utilizing the shear cell technique and achieving stable density layering with the addition of an alloying element Bi, the self-diffusion coefficients of liquid Sn were measured on the ground at 573 K, 773 K, and 973 K (300 °C, 500 °C, and 700 °C). Moreover, the impurity diffusion coefficients of Bi in the liquid Sn were simultaneously measured, to confirm the suppression of natural convection. From the experimental results, natural convection was confirmed to be suppressed, given that the impurity diffusion coefficients of Bi were in good agreement with the microgravity reference data. Upon changing the amounts of added Bi within 5 at. pct Bi, the self-diffusion coefficients of liquid Sn did not vary significantly. Moreover, the SnBi system within 5 at. pct Bi can be regarded as a dilute solution by calculating the activity of Sn in the SnBi system beforehand. The self-diffusion coefficients of the liquid Sn were in good agreement with the power law of temperature dependence from the microgravity reference data. After confirming the suppression of natural convection and that the SnBi system is a dilute solution, the self-diffusion coefficient of liquid Sn was determined as 5.00 ± 0.16 × 10−9 m2 s−1 at 773 K (500 °C). The effectiveness of the experimental method used in this study for the measurement of the self-diffusion coefficients was confirmed, under the condition that the liquid system could be regarded as a dilute solution.

Effect of high‐pressure homogenization on the flow properties of citrus peel fibers

AbstractIn this study, high‐pressure homogenization process with two different pressures (90 MPa/13,000 psi and 160 Mpa/23,000 psi) was used to pretreat the citrus peels fiber. Soybean oil was added to the citrus peels fiber before high‐pressure homogenization process, and the effect of four different percentages (0, 50%, 150%, and 300%) of oil to fiber on behaviors and physical properties were measured. Shear cell technique was used to measure the flowability index and powder cohesion of these powder samples. The physical properties, including particle size in suspension liquid, bulk density and scanning electron microscopy images of powder were also measured to ascertain the relationship between the structural changes and the flow property variation. The results show that the high‐pressure homogenization process can change the granular structures and produce large quantities of tiny pores on the surface of the citrus fiber. Meanwhile, the particle size in suspension liquid and bulk density of powder decreased after this treatment. With the increase of the ratios of oil to fiber, the flowability index decreased and the powder cohesion increased. For the physical properties, the bulk density improved and the particle size in suspension liquid decreased; simultaneously, the number of pores on the surface of the fiber increased. Altering pressure for the high‐pressure homogenization process also change the microstructure and flow properties which presented lower particle size in suspension liquid and higher bulk density.Practical applicationsThis simple and low cost process can efficiently and effectively improve the physical, chemical, and functional properties of various fibrous materials, including surface area, water holding capacity, texture, viscosity, etc. Therefore, this process can be used to develop new value‐added products and ingredients from various agricultural fibrous byproducts, such as fruit peers or pulps, seed coats, straws and leaves, etc. In addition, these new value‐added ingredients can still be classified into the clean label category that is highly significant to the quality and healthy food market.

Combined interdiffusion and self-diffusion analysis in Al-Cu liquid diffusion couple

In this paper, a recent combined isotope and interdiffusion analysis is adapted to the case of binary liquid alloys. Shear-cell interdiffusion experiments with a layer enriched in 65Cu sandwiched between the interdiffusion couple ends have been performed on liquid Al-Cu that is suitable for demonstration of the application of this analysis. (Note that the analysis is not limited to the use of the shear-cell technique.) The self-diffusion coefficient of Cu is then obtainable as a function of composition. Results of the new analysis are in good agreement with an independently measured Cu self (tracer) diffusion coefficient at two compositions.

A multi-slice sliding cell technique for diffusion measurements in liquid metals.

The long capillary and shear-cell techniques are traditionally used for diffusion measurements in liquid metals. Inspired by the idea of the shear-cell method, we have built a multi-slice sliding cell device for inter-diffusion measurements in liquid metals. The device is designed based on a linear sliding movement rather than a rotational shearing as used in the traditional shear-cell method. Compared with the normal shear-cell method, the present device is a more compact setup thus easier to handle. Also, it is expected to be easier to monitor with X-rays or neutrons if used in in situ experiments. A series of benchmark time-dependent diffusion experiments in Al-Cu melts carried out with the present technique reveal that accurate diffusion constants can be achieved only after a sufficient time. For short annealing times, the initial shearing process causing convective flow dominates the measurement and leads to an increase of the measured diffusion coefficient by a factor three. The diffusion data obtained for Al-Cu liquids are consistent with the most accurate data measured by the in situ X-ray radiography method under well controlled conditions of no temperature gradient or other perturbation. High accuracy and easy handling as well as superior adaptability make the present technique suitable for diffusion studies in liquid metals.

A sliding cell technique for diffusion measurements in liquid metals

The long capillary and shear cell techniques are the usual methods for diffusion measurements in liquid metals. Here we present a new “sliding cell technique” to measure interdiffusion in liquid alloys, which combines the merits of these two methods. Instead of a number of shear cells, as used in the shear cell method, only one sliding cell is designed to separate and join the liquid diffusion samples. Using the sliding cell technique, the influence of the heating process (which affects liquid diffusion measurements in the conventional long capillary method) can be eliminated. Time-dependent diffusion measurements at the same isothermal temperature were carried out in Al-Cu liquids. Compared with the previous results measured by in-situ X-ray radiography, the obtained liquid diffusion coefficient in this work is believed to be influenced by convective flow. The present work further supports the idea that to obtain accurate diffusion constants in liquid metals, the measurement conditions must be well controlled, and there should be no temperature gradients or other disturbances.

MSL compatible isothermal furnace insert for high temperature shear-cell diffusion experiments

For long-time diffusion experiments shear-cell techniques offer more favourable terms than the traditional long capillary techniques. Here, we present a further developed shear-cell that enables the measurement of diffusion coefficients up to temperatures of 1600 °C. Hence, diffusion experiments can be carried out at temperatures not accessible until now by conventional capillary or shear-cell techniques. The modified shear-cell, which can contain up to six samples of a total length of 90mm and a diameter of 1.5 mm, is built of 30 shear discs of 3mm thickness each. It is operated in an isothermal furnace insert which can be accommodated in the Materials Science Laboratory of the International Space Station. This provides the opportunity that the shear-cell can be applied to microgravity and to ground-based experiments, respectively. The heater insert with an overall length of 518mm and a diameter of 210mm consists of four heating zones with a total power of 3.5 kW. Temperature homogeneity along the graphite sample compartment is better than 2K at 1600°C. Details of the new design are discussed and results of first successfully performed heating and shearing cycles are presented.

Diffusion Coefficient Measurements Under Reduced Gravity Conditions by Means of the Shear Cell Technique. The Impact of Free Surfaces

A recent computational methodology is applied here in order to analyze the impact of free surfaces on the measurement of the interdiffusion coefficients if shear cells are used. Calculations indicate that the above-mentioned impact depends on the intensity of the solutal Marangoni convection but mainly on the number of active Marangoni segments, that is to say, on the extent of the free surface considered. Bulk solutal convection due to reduced gravity levels is not relevant if the gravity vector acts orthogonally to the gradient of concentration.

Diffusion measurements using the shear cell technique: Investigation of the role of Marangoni convection by pre-flight experiments on the ground and during the Foton M2 mission

An experimental investigation on the disturbing influence of the solutal Marangoni convection during diffusion measurements is presented. We used the systems Sn–Bi, Pb–Ag and Sn–In with decreasing differences in surface tension. For all systems we measured surface tension and – under varying free surface conditions – diffusion coefficients. We succeeded in measuring diffusion coefficients on the ground under nearly non-free surface conditions. The results are compared with the results of the FOTON M2-satellite mission with similar μg-experiments. We show that temperatures from around 400 °C to about 800 °C and the degree of free surfaces influences strongly the measured value for the diffusion coefficient.

Impurity diffusion measurements of Bi in liquid Sn using stable density layering and the shear cell technique

To obtain reliable diffusion data on earth, impurity diffusion experiments of Bi in liquid Sn were performed using a stable density layering and the shear cell technique with a reservoir system to provide pressure on the liquid. The experiment type was diffusion of Bi from a SnBi3at.% (5wt%) thick layer into Sn. The diffusion temperatures (diffusion times) were 300°C (8h), 500°C (4.5h) and 800°C (2.5h). At each temperature four parallel experiments were performed simultaneously in one shear cell cartridge. After the diffusion experiments, the Bi concentration profiles were measured by atom absorption spectroscopy. The diffusion coefficients were determined by fitting with the thick layer solution considering the correction method of the shear convection and the averaging effect. As a result, the concentration profiles had only small deviations and the diffusion coefficients agreed well among the four parallel experiments. The mean diffusion coefficient at 300°C agreed well with data from the 1g-diffusion experiments in a magnetic field and with μg-data. It was also shown that this method can be applied also to interdiffusion experiments, in which the influence of Marangoni convection can be investigated by the variation of the pressure inside the capillary and artificial free surfaces on the liquid sample. The temperature dependence of the diffusion coefficient was empirically described as the nth power law (n≈1.8) of T.

Measurement of diffusion coefficients of Au in liquid Ag with the shear cell technique

Diffusion coefficients of Au in liquid Ag were measured at the temperatures 1300K and 1500K by using the shear cell technique. The adopted technique was a modified long capillary method which had a diffusion couple configuration. Obtained diffusion coefficients of Au in liquid Ag were respectively 2.30×10−9m2s−1 at 1300K and 3.16×10−9m2s−1 at 1500K, which were in good agreement with calculations based on the hard sphere mixture model.

Diffusion measurements on a liquid monotectic alloy PbGa using the shear cell technique under µg in the foton-M2 mission and under 1G

Diffusion experiments of a liquid monotectic alloy PbGa were performed under 1g-conditions at 623, 773 and 903K, and under µg-conditions at 903K. As a measurement tool the shear cell specially designed for Russian satellite Foton missions within the AGAT-furnace was used to have a homogenization time before the diffusion and to avoid the influence of decomposition into two liquid phases during cooling-down. The experiment type was diffusion from a thick layer of PbGa5at% into pure Pb. The liquid sample in the capillary was pressurized using a reservoir system in order to minimize Marangoni convection. In 1g-experiments the diffusion axis was arranged vertically and the sample was set such that the density increases monotonously parallel to the gravity vector in order to suppress buoyancy convection. Four experiments were performed simultaneously for each set-up. The µg-experiment was performed in the AGAT facility during the Foton-M2 mission (June 2005) where one capillary was assigned for the PbGa-Pb experiment (PbGa was containing an enriched Pb-isotope tracer). The concentration profiles were obtained by AAS (1g) and by ICP-MS (µg). The diffusion coefficients were evaluated by fitting with the thick layer solution. For the evaluation a correction method was used for the shear convection and the averaging effect inside each cell. As a result, the obtained concentration curves agreed well with the fitting function. The reproducibility of the diffusion coefficients among four parallel 1g-experiments was good with a standard deviation among four capillaries smaller than 5.5% including the standard temperature deviation. The diffusion coefficients agreed well between 1g- and µg-experiments. The temperature dependence of the diffusion coefficients could be fitted well to a power law with an exponent about 2.4. From these results we conclude that the 1g-experimental method in this study for diffusion measurement is effective also for monotectic systems.

Interdiffusion in liquid tin

The interdiffusion coefficients of Zn, Ag, Sb, Pb, and Bi in liquid Sn were determined using both shear cell and long capillary techniques. These elements were chosen to provide a range of valences and atomic radii, variables that are expected to affect the interdiffusion coefficients. The results indicate that Sb and Ag diffuse in liquid Sn at the same rate as does Sn itself. Bi and Pb appear to diffuse more slowly in liquid Sn than does Sn. Zn appears to diffuse more rapidly in liquid Sn than does Sn itself. These results indicate that the atomic radius is an important variable for interdiffusion in liquid Sn. However, the results for the interdiffusion of Zn, Pb, and Bi, were more scattered than those for Ag and Sb, suggesting that some convective mixing, due possibly to transverse temperature gradients, may be occurring even in capillaries with only 1.5 mm diameters.

Shear cell development for diffusion experiments in FOTON-Satellite missions and on the ground with consideration of shear-induced convection

A shear cell technique was developed to obtain exact diffusion data. The shear cell in this study was designed for the utilization under μg-conditions, especially in the FOTON-M2 mission, but also under 1g-conditions. To minimize the influence of the shear convection, the cell size, the rotation system and the speed of the discs were optimized. To minimize free surfaces, which can cause Marangoni convection, a reservoir system providing pressure on the liquid was introduced. Using this FOTON shear cell we performed short-time diffusion experiments in the In-Sn system in a parabolic flight and under 1g conditions to investigate the influence of the shear convection quantitatively. As a result, the influence of the shear convection was so small that the mean square diffusion depth caused by the shear convection was in the order of10− 7m2, which is smaller than 1% of the typical value Xdiff2 ≈ 10− 4m2 in a standard diffusion experiment using the FOTON shear cell. By using this result a correction method for the evaluation of the diffusion coefficient was established. In several ground experiments, the FOTON shear cell showed the same diffusion coefficients as from μg reference experiments within the range of errors and no obvious indication of Marangoni convection was detected. From these results we confirmed that the FOTON shear cell can be applied to μg-experiments and ground-based experiments as well.

Effect of storage conditions on the wall friction characteristics of three food powders

This work presents an evaluation of the effect of storage conditions (temperature, relative humidity and storage time) on wall friction characteristics and hopper design for flour, tea and whey permeate powders. Jenike’s shear cell technique was applied to evaluate the wall friction, in particular, the wall yield locus and angle of wall friction, and to evaluate the minimum hopper angle required for mass flow. Wall friction increased with temperature for flour and tea powders while it decreased for whey permeate powder. The effect of relative humidity on wall friction and hopper design was significant. All powders sorbed moisture when exposed to air with relative humidity in the range of 22–66%, which resulted in an increase in wall friction and hopper angle requirement with increasing relative humidity. A consolidating bench was used in the investigation of storage time. Seven day storage time did not affect significantly the wall friction of flour, but did affect the wall friction of both tea and whey permeate powders. This work demonstrates the importance of performing wall friction tests for a number of possible variations in storage conditions in order to assess how these affect hopper design or how they may affect the flow pattern in an existing hopper.