Integrated pest management (IPM) is invaluable in fighting parasitic diseases carried by freshwater snails as disease-transmitting vectors. Here, we studied the effectiveness of two non-GMO monosex decapods, the giant freshwater prawn Macrobrachium rosenbergii and the Australian redclaw crayfish Cherax quadricarinatus, as biocontrol agents against such disease-transmitting snails, namely, Melanoides tuberculata, Thiara scabra, Tarebia granifera and Haita acuta, found in fishponds. In food-choice experiments, the two decapods preferred snails which had thinner, weaker shells, with this feeding selectivity being stronger for the prawns than for the crayfish, which demonstrated more opportunistic feeding behavior. Notably, the crayfish were more efficient in snail predation than the prawns, displaying both shorter handling times and lower encounter rates. Subsequent physical-mechanical tests on the snails revealed that the snail species least preferred by the prawns had significantly 2.5 times thicker shells, which required 8 N more force to initially break. Practical implication: our findings suggest that the two monosex decapods could provide sustainable biocontrol solutions, potentially enhancing IPM strategies in aquaculture and offering win-win-win sustainable polyculture for fish farmers, with the biocontrol agent, which could be tailored to farmers' preferences, doubling as a valuable polyculture-produced protein.

The terminal velocity and drag coefficient are vital parameters for designing industrial systems involving free-falling particles. While the literature on spherical particles is abundant, that on non-spherical particles is scarce. Therefore, a comprehensive experimental study was conducted using discs, cylinders, and irregular particles of various sphericities in various fluids. First, the flow mode was analyzed, and seven flow modes were identified and described in a flow regime map. Subsequently, the terminal velocity and drag coefficient were correlated depending on the sphericity of three trends. The first is for nearly spherical particles with sphericities over 0.87, and the other two trend lines are for sphericities lower than 0.87, one for discs and the other for cylinders. Additional experiments enabled the extension of the models to nearly spherical, flat, and long particles within an error of ±30%.

The acceleration length of nonspherical particles is required for various aspects of system design. However, no simple or usable equations can be found in literature. Therefore, this study is designed to show that the force balance developed earlier for spherical particles, including the new exponential function for the history force, is also valid for nonspherical particles. To achieve this, a new history force parameter definition considering sphericity has been developed based on numerous experiments. The experimental results confirm the definitions of particle acceleration and velocity of nonspherical particles. The acceleration length can be described as a function of the Archimedes number, density ratio, and particle diameter by analogy to spherical particles, considering the terminal Reynolds number, drag coefficient, and history force parameter as functions of the sphericity. In most cases, the acceleration length describes the experiments well, but it is less accurate for cases of orientation change during acceleration.

Flowability is important for characterizing particulate materials. Some simple measurements, such as the Hausner ratio and angle of repose, are used to compare materials, and more sophisticated devices, such as the Jenike shear cell and ring shear tester, are used for design purposes. However, these devices are only used for measurements in air; thus, underwater operations lack such measurements and design models based on flowability measurements. This work shows that flowability can be measured underwater by simple modifications to the apparatuses. Although underwater flowability was found to be much smaller than that in air owing to negligible cohesive forces, such an approach enables the adoption of models developed for systems in air for underwater system design. In addition, more in-depth research on particulate material structure and flow by eliminating van der Waals forces can be conducted.

Acceleration length and time are required for various aspects of system design. However, simple and accurate equations that can be used by designers are lacking. Therefore, in this study, we used previously conducted tests and the simple exponential model to describe particle velocity and acceleration and thereby calculate the ac-celeration length, which is the length required for a particle to achieve 99% of the terminal velocity. Results indicated that the acceleration length can be well described by a function of the Archimedes number, density ratio, and particle diameter. Several new tests were conducted to measure the particle velocity as a function of time. These tests confirmed the newly developed model that describes the particle location, velocity, and ac-celeration as functions of time. Based on the new model, the acceleration time was calculated and found to be well described by the acceleration length and terminal velocity.

The angle of repose, angle of tilting, and Hausner ratio are frequently used to estimate the flowability of a particulate material. Also, the free and tapped densities are commonly used for design and operating of particulate solids handling systems. In this study, these properties were determined for mono-sized, binary mixtures and particle size distributions of spherical glass. It was found, as in previous studies that the mono-sized properties can be described as simple functions of Archimedes number. The binary mixture tests enabled to develop empirical models to describe the properties as functions of the small particles weight ratio. They also clearly revealed that segregation was a major concern for the angle of repose experiments. By using a logistic function for the particle size distribution tests and normalizing properties by their values for mono-sized particles at the median size, a common equation describing the behavior of all the investigated properties as a function of the distribution parameter was obtained.

The equation of motion for an accelerating particle is complicated to solve, primarily because of the Basset-history term. Therefore, most solutions found in the literature are numerical. Various experiments conducted with different particles and fluids have been presented and analyzed in this study. A simple exponential function for the particle velocity was found to fit all the experiments, describing the acceleration as a function of distance. Consequently, a simple exponential equation was developed for velocity. These functions depend on the initial acceleration and terminal velocity. While the terminal velocity can be predicted by several known equations, the initial acceleration was defined without any empirical parameter for cases of negligible history forces. In addition, the effect of history forces was correlated. Consequently, the velocity during the acceleration of 51 experiments was predicted to be ±10%.

Void fraction and bulk density are the fundamental characteristics of most practical analyses of particulate materials. Most industrial particles are not spherical and can have various shapes. In this study, the effect of particle shape on the free and tapped void fractions was tested. Based on the analysis of well-defined geometries, high circularities was considered equivalent to sphericity. All the experiments conducted with a high Archimedes number (Ar), where the Ar effect was negligible, demonstrated that three trend lines were obtained as a function of sphericity for long, flat, and high-sphericity particles. Two factors can be defined by dividing the void fractions of the non-spherical particles by that of spherical particles, namely, the shape and Ar factors. Accordingly, the void fractions are calculated and predicted to be within +/- 5% for free void fractions and +/- 7% for tapped void fractions.

The angle of repose, angle of tilting, and Hausner ratio are frequently used to estimate the flowability of particulate materials. In addition, free and tapped densities are commonly used for the design and operation of systems for handling particulate solids. In this study, these properties were determined for mono-sized and particle size distributions of three non-spherical particle materials. Based on previous and additional new measurements with new size fractions of mono-sized particles, it was found that mono-sized properties can be described as simple new functions (replacing the previous correlations) of the Archimedes number. Mixtures with wider size distributions were defined using logistic functions based on the median size and distribution parameter. Normalizing the measured property by the median size and assuming it to be mono-sized enabled finding a simple relation to the distribution parameter, equivalent to that found for spherical particles. Thus, the appropriate properties can be predicted based on the size distribution.

The current work involves experimental and computational study of rotary drum cross-sectional characteristics such as: kinetic angle of repose (AoR), flight holdup, flight geometry and flight discharge energy. Experiments with two spherical and three non-spherical particulate materials with sizes between 70 μm and 2 mm were performed in a home-made rotary drum to measure the kinetic angle of repose as a function of flight angular position and drum rotational speed. As a result, an empirical model was proposed to predict the kinetic AoR as a function of the Archimedes number (Ar), Froude number (Fr), and flight angular position. The kinetic AoR predicted by the model is fairly correlated with the experimental findings, with an error of ±8%. The effect of moisture was also examined for a single case of material type and percentage of moisture content, and the results indicated that the same model for dry material can be applied to moist material. In addition, a simple computational algorithm was introduced to predict the flight holdup for any angular position of the flight. Validation using experimental data from the literature demonstrated the soundness of the model. Furthermore, a discharge energy characteristic was introduced, and a parametric study showed that this characteristic can be used as a new key parameter for optimization purposes.

Empirical correlations and experimental works relating the drag coefficient (C-D) of spheres to the Reynolds number (Re) and Re to the Archimedes number (Ar) were reviewed with a focus on the correlations applicable to the entire Re range. In addition, experiments with various spherical particles and fluids for the entire range of Re were conducted using high-speed video and added to the literature data. One of the correlations from the literature for Re-Ar and a modified correlation for C-D-Re were found to best fit the experimental results. The analysis also established new correlations for Re-Ha (a non-dimensional number for velocity not including particle size) and C-D-Ar. The latter is easier to use than the common C-D-Re curve. (C) 2021 Elsevier B.V. All rights reserved.

Particle velocity, acceleration length and velocity profile evaluations are essential for the design and modeling in conveying systems. Although the subject has been widely researched, the relationship between pneumatic and hydraulic systems has not been addressed and still lacks a model that will be consistent over various operating conditions and materials and that includes both conveying media. The current paper presents a thorough experimental investigation of the above-mentioned characteristics obtained from a 75 mm (3 '), 50 mm (2 ') and 38 mm (1.5 ') hydraulic conveying system. Experiments with various operating conditions and conveyed materials in vertical and horizontal pipes of a hydraulic transport system were conducted. The experimental results were compared and combined with experimental data on pneumatic conveying. The particles' velocities in the pipe were obtained using a high-speed camera combined with image processing. Data was obtained for each particle allowing an investigation of the effect each component has on the phenomenon. Correlations are suggested for the characteristics' evaluation in the range of the tested operating conditions. (c) 2020 Elsevier B.V. All rights reserved.

In this study, single particle compression and impact tests were employed to measure various parameters such as the projected area of indentation, kinetic energy, and mechanical work done to deform the particle and the surface. The experiments were conducted with various particulate materials, including glass, steel, and ceramic spheres, and silica gel particles. In addition, various surface materials were tested, including two aluminum alloys, a steel alloy, stainless steel, brass, and PVC. The analyses showed that the compression force and work clone to deform the surface were both linearly dependent on the projected area of indentation and apparent volume of indentation, respectively. Additionally, the slope of the compression force with respect to the projected area of the indentation graph represented the hardness of the surface material. It was also shown that, for the measured range of impact velocities (10-65 m/s), the applied force during impact was identical to the static compression force, with a deviation of +/- 20%. Lastly, a semi-empirical model was developed to estimate the percentage of total kinetic energy required to deform the surface and the particle in an elastic-plastic manner. The model exhibited a reasonable agreement with the experimental results, with deviation of +/- 10%. (C) 2020 Elsevier B.V. All rights reserved.

This study presents a new theoretical model for granular materials flow regimes during discharge from wedge-shape (planar) silos. The new model takes into account the influence of granular material properties, material height, bin and hopper geometrical dimensions and consider the possible difference between the bin and the hopper wall friction coefficients. In addition, the model allows to found an appropriate transition between mass flow and two kinds of funnel flow regimes. By comparing the new model assessments to experimental results, which were found in the literature, good agreement was achieved. Based on the new model equations a generalized flow regime map was presented. The proposed generalized flow regime map should help designers to increase accuracy and flexibility in the granules flow regime assessment and therefore might improve significantly the process efficiency.

The angle of repose, angle of tilting, and Hausner ratio are frequently used to estimate the flowabilities of particulate materials. In this study, these parameters were measured for 65 samples. A visualization study showed that there are three mechanisms affecting the angle of repose. Only one is directly related to the flowability. Crucially, to eliminate the effect of wall friction, the measurement of the angle of repose should be conducted on a high-friction surface (such as one covered in glue) or within a ring. Further, although all three parameters can be described as a function of the Archimedes number, the performance of each material was different; thus, the results cannot be generalized. Only the Hausner ratio could be defined reasonably by a single function. A new flowability classification was developed for the three parameters, and the best metric to define flowability was found to be the Archimedes number.

This study analyzes the effect of moisture content and compression pressure on bed void fraction in different materials. The void fractions of several materials, both spherical and non-spherical, solid and porous, with different particle sizes and densities, were evaluated as functions of moisture content and compression pressure. In our previous study, the Archimedes number was found to be an appropriate parameter to describe particle behavior. In this study, the Archimedes number was found to be an appropriate non-dimensional number to describe the effects of moisture content and compression pressure. A general equation was developed to evaluate the effect of moisture content on liquid bridge forces in solid and porous particles. Furthermore, a general equation was developed based on the Heckel model to describe compressed particulate beds. Finally, we studied the compression of wet particles. The general equations presented in this study agree well with the experimental values.

This paper presents a parametric study and a new design procedure for wedge-shaped (planar) silos. The analytical part of the study is based on a previously reported theoretical model and considers the influence of granular material properties, material height, bin and hopper geometrical dimensions, and the possible difference between the bin and hopper wall friction coefficients. This study includes new experimental results and analyses regarding the influence of various parameters. It was found that the mass–funnel flow boundaries were almost indifferent to the bin sidewall roughness. In addition, according to the new results, the mass flow mode could be achieved even for very rough hopper walls, but in that case, a stagnant layer of material exists next to the hopper walls. Finally, a new design procedure for planar silos was proposed. The new procedure should help operators and designers of silos to increase the accuracy and flexibility in the assessment of granular flow regime, and therefore it might significantly improve the process efficiency.

The angle of repose, angle of tilting, and Hausner ratio are frequently used to estimate the flowability of a particulate material. In this study, these factors were determined for 12 samples as a function of the moisture content. The measurements were thoroughly analyzed and indicate that the angle of tilting is the most appropriate for describing a material's response to moisture content. The flowability results clearly showed three types of materials according to their response to moisture content: solid particles, porous particles, and size-changing particles. A thorough analysis of various sizes of spherical solid particles enabled the identification of five zones from dry to fully immersed in water, and a zone map could be obtained. In addition, a model predicting flowability as a function of moisture content and Archimedes number could then be developed. Further experiments are required to relate the zone map and model to other types of materials.

The pick-up velocity is a threshold velocity that is considered when designing hydraulic or pneumatic conveying systems. Defining the conveyed particles as 'settling' or 'non-settling' affects the calculation method of the pressure drop over a hydraulic conveying system. Rheometers are commonly used to measure the dynamic viscosity of liquids and suspensions. In this work, a unique method of using a rheometer is presented. The method enables simple measurement of the pick-up velocity by increasing the rotational speed of the rheometer. In addition, characterizing the particles as non-settling is achieved by decreasing the rotational speed. The results of this work correlate well with previously published results, confirming that these two parameters can be found by conducting very simple and quick measurements.

Particulate bed compression is widely applied in various industries to break particles in comminution units or to manufacture tablets by compressing the particles to high pressures. Analyzing the medium range of compression pressures (compression stress) is complicated, as a number of phenomena occur simultaneously: particle rearrangement, force chain formation, particle breakage, particle bonding, and finally tableting. All of these phenomena affect one another and cannot be separated. However, the ability to quantify each of these phenomena and consider the strength of individual particles may lead to better understanding and design of the processes involved. The phenomenological research presented in this paper shows a number of interesting phenomena. Through experiments and extensive visualizations particle breakage within the compressed bed and individual particle crush were compared to show that particles within a bed will break at lower average pressure. In the same way, other phenomena are revealed, such as: breakage ratio in a compressed bed is limited and the strongest particles survive, the fine debris are required for bonding.