Movement of the particle on the surface of the conveyor belt, arbitrarily oriented in space

The movement of the material on the inclined belt of the conveyor takes place during transportation or its frictional cleaning. For an inclined moving plane (slide), the angle of its inclination to the horizontal plane is decisive. The absolute motion of a particle is the sum of two motions - the portable belt and the relative particle along the belt, so it is affected by the angle between the vectors of the greatest inclination of the plane and the transfer velocity of the plane (tape). The purpose of the study is to determine the motion of a material particle on the conveyor belt for the case when the angle between the vector of the line of greatest inclination of the conveyor plane and the direction of its transfer speed is arbitrary. To do this, the conveyor belt element was depicted as a rectangle with an axis of symmetry drawn along the direction of translational movement. In the initial position, the plane was placed horizontally, so the angle of greatest inclination is absent. In the future, the plane was given an arbitrary location in space due to alternate rotation around the sides bounding its compartment or around the axes of symmetry of the compartment, which is equivalent. The relative and absolute motions of the material particle along the moving web of the conveyor are considered for the case when the line of the greatest inclination of the web plane makes an arbitrary angle with the direction of the portable motion of the web. A system of differential equations of motion is compiled and solved. The obtained results are illustrated graphically. It is established that the nature of the relative motion of a particle on an inclined plane moving rectilinearly and uniformly depends on the direction of the vector of the line of the greatest inclination and the value of the angle of inclination of this plane. If the angle of inclination is less than the angle of friction, then the lateral feed of the particle will eventually stop either on the curved section of the trajectory or on a straight line that is parallel to the line of greatest inclination. The stopping place of the particle depends on the value of the initial velocity. At an angle of inclination of the plane equal to the angle of friction, the particle during the movement along the curved section of the trajectory reduces its initial velocity by half and then moves in a straight line and evenly. If the angle of inclination of the plane is greater than the angle of friction, the particle in relative motion along the curvilinear section of the trajectory first reduces the velocity, and when approaching a rectilinear section, its velocity increases and continues to increase on a rectilinear section of the trajectory. Key words: material particle, conveyor, inclined plane, plane inclination angle, particle velocity

Verification of strength resistance of sandy soil using small scale penetrometer tests

This study focuses on utilizing cone penetrometer models to determine strength (resistance) of sandy soil and also assessment how the relative density and the angle of friction effects on the measured cone penetration resistance in sandy soil. Simple empirical equations are used also to determine the cone penetration resistance components such as the sleeve resistance and the tip resistance. Simple comparison is performed between the measured and calculated soil strength and well agreement is noticed between them.

SCREW DESCENT, ANALYTICAL DESCRIPTION OF WHICH INCLUDES THE EQUATION OF PARTICLE MOVEMENT ON AN INCLINED PLANE

To study the modes of particle movement depending on the constructive parameters of the surface, it is important to have analytical dependencies of this movement. An analytical description of the movement of a load on the example of a material particle on the surface of a gravitational descent formed by a screw conoid and a coaxial vertical limiting cylinder was developed in the article. It makes it possible to find the constructive parameters of the descent, which will provide the required speed of the transportation. If the surface of the confining cylinder is absolutely smooth, then the movement of the particle along such a descent will be uniformly accelerated or equally slowed down depending on the value of the angle of inclination of the plane, that is, similar to movement along an inclined plane. If the angle of inclination of the plane is equal to the angle of friction, then the particle will move with a constant angular velocity of rotation, then one can find the linear velocity, which will also be constant. The value of this speed will be equal to the initial one. If the angle of inclination of the plane is equal to the angle of friction, but the coefficient of friction is not equal to zero, then the particle will be decelerated due to the action of the friction force of the particle on the surface of the cylinder. This is the difference from descent along an inclined plane, along which the particle in this case will move at a constant speed. In the general case, when the angle of ascent of the helix is ​​greater than the angle of friction, the driving force and the force of friction on the surface of the conoid and on the surface of the cylinder are balanced with each other and the angular velocity of rotation of the particle becomes constant. Consequently, it is possible to provide the required speed of transportation of the material at various ratios of the structural parameters of the surface with known coefficients of friction. To reduce the overall dimensions of the screw descent, it is necessary to reduce the radius of the limiting cylinder; however, with this limitation, the weight of loads should be taken into account.

MOISTURE-DEPENDENT PHYSICAL PROPERTIES OF MEDICAL TINY SEEDS: PART A: FLIXWEED (DESCURAINIA SOPHIA L.)

Knowledge of agricultural seeds’ physical properties has significant importance for machinery and processing equipment design. Physical properties of flixweed (Descur ainia sophia L.) seeds were determined as a function of moisture content. Several properties were studied in the moisture range from 5.28 to 17.53% dry basis. Also, probability distribution of seeds’ principal dimensions were modeled by Gamma, Generalized Extreme Value, Lognormal, and Weibull functions. With increasing moisture content from 5.28 to 17.53%, properties including; length, width, thickness, geometric and arithmetic mean diameter, sphericity, specific surface area, volume, and projected area showed no specific trend. In contrast, the surface area increased from 6×10-7 to 1×10-6 m2. The bulk and particle density decreased from 696.61 to 542.51 kg·m-3, and 1217.50 to 1189.02 kg·m-3, respectively. The porosity increased from 42.78 to 54.37%. The maximum external static angle of friction belonged to wood at all moisture content levels, followed by the iron and galvanized surfaces. At all moisture levels, the emptying angle of repose was more than the filling one.

MOISTURE-DEPENDENT PHYSICAL PROPERTIES OF MEDICAL TINY SEEDS: PART B: SUMMER SAVORY (SATUREJA HORTENSIS L.), BASIL (OCIMUM BASILICUM L.), CRESS (LEPIDIUM SATIVUM L.), AND AJOWAN (CARUM COPTICUM L.)

One of the most critical challenges of determining tiny seeds’ engineering properties is their dimensions. In the present study, a method based on digital image processing was employed to investigate the moisture content’s effect on geometric properties of summer savory, basil, cress, and ajowan seeds. Also, the gravimetrical and frictional properties of the seeds were measured. Gamma, Generalized Extreme Value, and Weibull distributions were used to model the probability frequency distribution of the seeds’ length, width, and thickness. This research indicated that the application of the image processing technique could be an excellent method to measure dimensional parameters of tiny seeds. Results showed that, with an increasing moisture content of seeds, the 1000-seed mass increased for basil, cress, and ajowan seeds; but, summer savory seeds showed that increasing-decreasing trend. For all four plant spices, increasing moisture content will result in the bulk density decrement. The particle density of summer savory, basil, and cress seeds decreased due to moisture content increment. However, the particle density of ajowan seeds increased with increasing moisture content. Results of measuring the angle of friction on iron, wood, and galvanized surfaces showed that, in most cases, the angle of friction increased by increasing moisture content. Also, except for the filling angle of repose of summer savory, increasing trends were observed for the emptying and filling angle of repose due to moisture content increment.

Study on the mechanics of textile thread in woven

Specialists in the weaving industry are often interested in the question of what tension of the warp and weft threads must be set on the weaving machine to produce a particular fabric. Along with this, they are interested in the question of what is the relationship between these parameters and the structure of the fabric, how much it is necessary to increase or decrease the tension of the warp and weft threads when changing the assortment of fabric. These problems arise because the correct thread tension on weaving machines increases the productivity of equipment and labor, and also improves the quality of the fabrics produced. The current state of the mechanics of a weighty deformable flexible thread on a plane and other forms of guides do not take into account the rigidity of the threads on the friction surface, since this parameter is determined by the type and type of threads, the linear density of the threads and the elastic properties of the threads. Therefore, the article analyzes the work on the mechanics of textile yarn and studies of the tension of the yarns were carried out depending on the radius of friction, angle of friction, coefficient of friction and stiffness of the yarns.

The forces acting on the teeth of catching machine

Republic of Uzbekistan, pumping stations are used in very difficult conditions. The presence of various particles and effluents in the water has a negative effect on the operating modes of the pumping equipment. Special grilles are installed to prevent the catching devices from entering the advance chamber of the pump station. The shape and length of the device covers are of great importance so that they are caught in front of the grilles and completely cover the accumulated debris. In the article, the laws of mechanics were used to determine the shape and size of the working device of the device for cleaning the effluent flowing into the pump station as water and accumulated in front of the grids. In doing so, the condition of ensuring complete removal of the leaks covered by the device was taken into account. It was argued that the angle γ between the working surfaces and velocities of the covers should be less than 90-φ over its entire working surface in order to fully cover the device shafts. It was found that when the working surface of the device is flat, the time of interaction with the catching device pieces is minimal. Studies and literature have shown that the angle of friction on the working surfaces of the device covers should be φ=20°, the angle between the working surface of the device cover and the rotational speed γ=70°.

Determination of the Friction Angle between the Wheat Ear and Stripper Fingers

Introduction. Determining the angle of friction between stripper fingers and a wheat ear is an important task aimed at finding the optimal design parameters and operating modes of stripping devices. When stripper fingers and wheat ears interact, the relative position of the ear glumes, flower glumes, and grains is densified. In this case, the spikelet surface roughness changes. Materials and Methods. A series of experiments was carried out to determine the angles of friction between a steel stripper fingers and wheat ears. Wheat varieties “Moskovskaya 40” and “Moskovskaya 56” were selected for the study. The experimental measuring installation is a frame with a rotatable platform mounted on it with the adjustable angle of rotation. The goniometer head provides the ability to fix the platform rotation angle value. The weight suspended from the stem of the plant imitated the forces arising in the process of stripping. The width and thickness of the wheat ear were also measured and recorded. Results. The influence of the size of the wheat ear on the angle of friction is determined. The results of the study are divided into two groups. The following values of the friction angles were obtained: 26.4–31.5° for the wheat with ear width of less than 10.4 mm; 22.0–27.1° for the wheat with ear width of more than 10.4 mm. Discussion and Conclusion. The angles of friction of wheat ears on the stripper fingers for wheat varieties specific to the Central region are obtained. The dependence of the angle of friction on the ratio of the geometric dimensions of the wheat ear and the slit width of the stripper fingers is established. When a wheat ear width is less than 10.4 mm, an effect of pinching the spikelets between the stripper fingers was observed. In this case, the coefficient of friction noticeably increased.

Research of particle movement on cylinder outer surface during its progressive oscillations in horizontal planes

The differential equations of relative movement of a particle on the external surface of the inclined cylinder which carries out oscillatory movement were received in the article. All points of the cylinder describe circles in horizontal planes. The equations were solved by numerical methods and the trajectories of the relative motion of the particle on the surface of the cylinder are constructed. Graphs of other kinematic characteristics as a function of time are given. Partial cases when the axis of the cylinder is located horizontally or at an angle of friction to the horizontal plane are considered.

Swelling clayey soils promote slope instability in the Muhunguzi watershed, western Burundi

<p>In Burundi, landslides are frequent on the western slope of the Congo-Nile ridge. Unfortunately, they are poorly studied and understood despite their deadly consequences. Previous reports have suggested that slope steepness, lithology and clay soils expose this slope to landslides, while heavy and intense rainfall is a trigger. However, the role of soil in the vulnerability of this specific slope to landslides is unknown. Here we investigate on soil characteristics involved in land sliding in this area.</p><p>We selected and sampled black and red soils in two Muhunguzi landslides. We determined the soil plasticity from Atterberg limits as well as the particle size distribution. In addition, we measured the soil weathering stage, and further identified the clay minerals from measuring the cation exchange capacity of the clay fraction and analyzing clay samples with X-ray diffraction (XRD).</p><p>Both the black and red soils are moderately weathered since TRB values in the B horizons range between 330 and 425 cmol(+) kg<sup>-1</sup>. The soils are loamy clayey to clayey (% clay: 33-55%), and contain high charge clay minerals. They do not differ in their Atterberg limits, which classify the soils as medium plasticity soils in the Casagrande plasticity diagram. Our data further show that both soils have a medium swelling potential. XRD show that the clay fraction consists of kaolinite and smectite and/or vermiculite. The latter 2:1 clay minerals are expandable and swelling clays, respectively. They give these two soils their plasticity and swelling properties. These two properties play an important role in the mechanical behavior of water-saturated soils. Indeed, swelling reduces soil cohesion while the plasticity index and the liquidity limit vary inversely with the internal angle of friction of the soil; cohesion and internal angle of friction being the fundamental parameters of the soil shear resistance. In addition, the soil mantle covers a hard schistose rock whose declivity is parallel to the soil surface slope. Thus, after intense rainfall during the wet season, the water-saturated soil reaches a level of liquidity sufficient to favor a landslide, all the more easily if the slope of the hard rock is inclined in the direction of the gravity flow.gru</p>