Special Drum Research Articles

Studies of the thermal stability of briquettes based on microsilica

The object of study in this work is microsilica. Microsilica is a pulverized technogenic waste generated during the smelting of technical silicon in industries. The intended use of this material is to obtain the highest quality grades of technical silicon in the end result without the use of expensive quartz. Microsilica is a finely dispersed powder, the direct processing (without preliminary preparation) of which into technical silicon is impossible in ore-thermal furnaces. That requires the manufacture of high-strength briquettes based on it, meeting all the requirements for raw materials for ore-thermal furnaces. In this paper, the authors present the results of a study of the thermal stability of microsilica-based briquettes in order to optimize the physicochemical properties of the resulting briquettes. The tested microsilica briquettes with various carbonaceous reducing agents (screenings of coke of thermo-oxidative coking, screenings of charcoal, etc.) were obtained on a large-scale laboratory roller briquetting press ZZXM-4. The evaluation of the thermal stability of the briquettes was carried out according to the method in which the resulting briquettes are subjected to thermal shock followed by abrasion on a special drum. The thermal resistance of a briquette is defined as the ratio of the weight of the main body of the briquette after the abrasion test to the sum of the weight of the main body and the crumbled material. The dependence of thermal stability on the granulometric composition of briquettes was also determined. The optimal granulometric composition was determined, with which the briquettes have satisfactory thermal stability. Thus, the most technologically advanced granulometric composition of the briquetting charge for reduction smelting in an ore-thermal furnace was established. It is best to use briquettes with granulometric compositions of the appropriate ratio of fractions 0-1; 1-3; 3-5 mm with the following proportions 35/35/30 and 60/20/15, as well as briquettes with particle size distribution within these ranges of variation.

Menguak Realitas Jejak “Goah” Sebagai Simbol Sakralitas Pertanian Di Desa Ciasmara Kecamatan Pamijahan Kabupaten Bogor

Agriculture is one of the important sectors that contribute to national income. However, agricultural development currently has a tendency to increase productivity so that it impacts on the agricultural system which tends to make agriculture is more just an activity that produces agricultural "commodities" Mainstreaming agriculture into "commodity agriculture" has an impact on the destruction of cultural infrastructure supporting agriculture. This study aims to: Identify "Goah" in Ciasmara Village, Pamijahan District, Bogor Regency. This study uses a Rapid-Ethnography approach, located in the village of Ciasmara, Pamijahan District, Bogor Regency from March 2019 - August 2019. This research found that in Ciasmara village there is still a "goah", but its form is no longer limited to a special space where to place rice but the "Goah" has transformed into another form such as a bucket or a special drum. The transformation form of the "Goah" is a result of the limitations of domestic space and the shift in the value of agricultural sacredity in the village.

Evaluation of the Role of Reclaimed Asphalt Pavement Preheating on Cracking Behavior of Hot Mix Asphalt Recycled Mixtures by Digital Image Analysis

Abstract In the last few decades, the need for reducing the exploitation of finite sources has led to an increasing use of reclaimed asphalt pavement (RAP) for the construction, maintenance, and rehabilitation of road pavements. During hot mix asphalt (HMA) plant production, RAP can be added at ambient temperature or preheated into special drums. When designing an RAP mixture, it is essential to dose the correct amount of virgin binder according to the percentage of the reactivated aged one. RAP preheating plays a key role in this process, although no reliable methods are available for achieving an accurate estimation. This article presents an innovative digital image-based methodology, named overlapped digital image (OIA) analysis, to better understand the role of reactivated binder on the cracking behavior of HMA-RAP mixtures. A recycled mixture was produced in the laboratory by adding RAP both at room temperature (25°C) and after preheating (150°C) and subsequently tested according to the Superpave IDT at 10°C and 25°C. The tests were combined with the OIA analysis to identify how the strain patterns and the initiation and propagation of fractures developed, according to the reactivation of the aged asphalt binder. The results show important outcomes in terms of cracking behaviors highlighting the important role of RAP preheating for inducing aged binder reactivation.

GRAVITY CHUTES, BUNKERS, GATES, FEEDERS AND DISPENSERS FOR BULK MATERIALS. LECTURE 7

The article presents materials of Lecture 7 in Theory of carrying and lifting, construction and road vehicles and equipment, which describes bunkers employed for storing and transporting bulk materials, manually and automatically controlled bunker gates, dispensers, gravity chutes, and special dispensers for mica and vermiculite concentrates. The release of bulk materials from the bunkers and the process of arching are analyzed; the pressure on the bunker walls and bottoms and the rate of release of bulk materials through the gates are determined. For a special drum mica dispenser, the feed and mica pulsation values are calculated; the optimal shape of a drum slot section is described. Calculations for two types of gravity chutes are presented.

Automatic control and detection systems for low-level radioactive waste drums

Vast quantities of low-level solid nuclear wastes are produced in the operation and decommissioning of nuclear facilities. These radioactive nuclear wastes are usually contained in special drums. Consequently, these nuclear waste drums must be tested, classified and their levels measured before they are placed in a final repository. There are certain dangers during the detection process; there is an urgent need for a safe, efficient, and autonomous system to inspect these nuclear waste drums. This study describes the methods involved in scanning and measuring the vertical section of radioactive waste drums and describes using the programmable logic controller (PLC-SIEMENS S7-1200) in order to construct an automated system as well as a detection system. According to the waste drum test flow, we designed a control program that utilizes the STEP7 Software as well as a monitoring program using SIEMENS WinCC that is flexible within the computer's central monitoring system. In the future, this system may be applied beyond the scale of a laboratory; nuclear enterprises may be able to adopt this process for sampling checks on contaminated waste. This study ensures the detection efficiency of waste drums as well as the safety of their operators. Furthermore, the proposed system effectively promotes the disposal and management of radioactive waste, which has potential applications in engineering.

The experimental measurement of the tyre casing defects for the freight vehicles at the dynamic loading

The paper deals with the experimental measurement of the tyre casing defects for the freight vehicles at the dynamic loading. The given investigation was mainly focused on cracks and defects in tyre casing, which is commonly used for freight vehicles. The mentioned measurement or investigation was performed under the strictly specified conditions. The given measurement of crack propagation in car tyre casing was based on changes of speed, changes of loading as well as changes of service time interval. It is important to point out that the pressure in the tyre was predetermined to be the constant value. The experimental procedures were carried out by help of special drum testing machine with designation: IGTT 25 kN – C and with the 1707 mm drum diameter. The mentioned measurement was performed for the area of tyre casing shoulder and it was in the site between the first and the second buffer lining. Using the ITT-1 program relating to non-destructive testing analyser, the CCD camera for testing procedure of tyre casing was used for the camera images which were taken from the internal side of the tyre casing.

Penurunan Ukuran Butir Serbuk Besi dengan Ball Milling 744 rpm dan Ball to Powder Weight Ratio 1:5

<em><span lang="EN">Creating a magnet with powder metallurgy technology, the materials to be processed must be available in powder form with a relatively very fine size, in micrometers (μm). In the magnetism of materials, grinding the material to obtain a very fine powder size is intended to obtain a magnetic material powder having a single domain. One tool commonly used to reduce the size of the powder to reach the size of a micrometer (μm) is a ball milling machine. This tool works by using hard balls in a drum. The balls are clashing each other with ground powder until the powder size becomes very small. Ball milling is using a strong material SS400, so it is expected to last long. While the special drum uses a base material of metal that is non-magnetic based Austenitic Manganese Steel. Ball uses a Ni-Hard ball. The AC motor measured with a stroboscope while carrying the load is 744 rpm. The process of smoothing that occurs inside the tube when the machine is run is the occurrence of collisions between Ni-Hard balls with the best grind sand is 83.3 grams with the number of Ni-Hard ball 101 fruit with a diameter of 10 mm and 75 pieces with a diameter of 11 mm, with using a 1:5 ratio. The process of shooting using Keyence optical microscope VHX 5000 with 200x bundle. Significant size changes occur with grinding with 10 mm diameter Ni-Hard ball from 15 minutes to 45 minutes. Then by using a Ni-Hard ball diameter of 11 mm also changed although not too significant.</span></em>

Deployment of Long Flexible Element on Spacecraft with Magnetic Damper

The present paper deals with the study of the dynamics of a spacecraft with a gravitational system of stabilization, with a magnetic damper, and pitch flywheel. Primarily the boom of the gravitational stabilizer is a prestressed tape wound on a special drum. When the drum starts deploying the tape, its takes the shape of an elastic long boom with the mass on its tip. The objective of the study is the mechanical and mathematical modeling and numerical simulation of the spacecraft dynamics. The equations of motion are derived with the use of the Eulerian-Lagrangian formalism. The information, which is obtained by a numerical simulation, gives the conclusion that the deployment and functioning of the spacecraft can be used to design a rational choice of parameters of the spacecraft. The data obtained allow choosing of the most suitable law of deployment and parameters of the magnetic damper. A detailed simulation has allowed analyzing the dynamic behavior of the design at various values of parameters of the spacecraft with the gravitational stabilizer. Data obtained facilitate selection the most appropriate deployment, structure and damper parameters.

Dynamics of spacecraft with gyro-gravitational system of stabilization due to elastic ring antenna deployment

This article deals with the study of the dynamics of the spacecraft with the gyro-gravitational system of stabilization. The deployment of a flexible ring antenna is performed after placing the spacecraft into orbit and completion of the preliminary damping by a special jet-propelled system, and after uncaging the gyros. Primarily, the antenna is a pre-stressed tape wound on a special drum. When the drum starts deploying the tape, it takes the shape of an elastic ring of variable diameter. The objective of the study is the mechanical and computational modelling of the spacecraft dynamics. The equations of motion are derived with the use of the Eulerian–Lagrangian formalizm. Numerical simulations of the operational mode of the system are conducted. Numerical results indicate that the system used for attitude stabilization ensures the shape of the deployed design and prescribed accuracy of the orientation. Simulation results are presented for the spacecraft model to show the effectiveness of the spacecraft and deployment process stabilization.

Spacecraft dynamics due to elastic ring antenna deployment

In this paper the dynamics of a spacecraft with a system of stabilization out-of-operation is studied. The deployment of the ring flexible antenna is performed after placing the spacecraft into orbit and damping the initially undesired rotations by a special jet-propelled system. Basically the antenna is a pre-stressed tape reeled on a special drum. Deploying from the drum, the tape takes the shape of an elastic ring of 30 m in diameter. The objective of the study is the mechanical and computational modelling of the spacecraft dynamics. The equations of motion are derived in Lagrangian form. Numerical simulations of operational mode of the system are performed. As it is shown in main result, which restrictions must be imposed on parameters of the process of deployment for maintenance of the shape of the deployed design.

Spacecraft dynamics with regard to elastic gravitational stabilizer deployment

The present paper deals with the study the dynamics of the spacecraft with gyro-gravitational system of stabilization. The deployment of the boom of the gravitational stabilizer commences after placing the spacecraft into the orbit and completion of the preliminary damping, when the gyroscopes are uncaged. Primarily the boom is the pre-stressed tape wound on the special drum. When the drum starts deploying the tape, it turns into the elastic cylindrical rod with the mass at its tip. The objective of the study is the creation of the generalized mathematical model and the conducting of the computer modelling of the spacecraft dynamics. The equations of motion are worked out with the use of the Lagrangian formalism. The numerical simulation of typical modes of system functioning is conducted. It is shown that the folding and the following deployment of the boom result in the turn of the spacecraft by 180° about the axis of the pitch. The results illustrate the behaviour of the main system variables.

Modeling the effects of the engineered barriers of a radioactive waste repository by Monte Carlo simulation

In the current conception of some permanent repositories for radioactive wastes, these are trapped, after proper conditioning, in cement matrices within special drums. These drums, in turn, are placed in a concrete container called a “module”, in which the space between the drums is back-filled with grout. Finally, several modules are stacked within the concrete walls of the repositories. Through this multiple barrier design, typical of the nuclear industry, the disposal facility is expected to ensure adequate protection of man and environment against the radiological impacts of the wastes by meeting various functional objectives which aim at limiting the release of radionuclides. Because one of the principal mechanisms of release of radionuclides is through water infiltration into the various constituents of the repository and subsequent percolation into the groundwater system, it is of utmost importance to study the phenomena of advection and dispersion of radionuclides in the artificial porous matrices hosting the waste (near field) and, subsequently, in the natural rock matrix of the host geosphere (far field). This paper addresses the issue of radionuclide transport through the artificial porous matrices constituting the engineered barriers of the repository's near field. The complexity of the phenomena involved, augmented by the heterogeneity and stochasticity of the media in which transport occurs, renders classical analytical-numerical approaches scarcely adequate for realistic representation of the system of interest. Hence, we propound the use of a Monte Carlo simulation method based on the Kolmogorov and Dmitriev theory of branching stochastic processes.

Ultrastructure of Mauthner cells in fish adapted to long-duration vestibular stimulation and the effect of ethanol.

Adaptation or resistance of fish Mauthner cells (M-cells) to long duration (2 h) vestibular stimulation (LDS)was produced by daily brief and gradually increasing vestibular stimulation (training). The LDS resistance was accompanied by an increase in the number of desmosome-like junctions in the afferent axosomatic synapses. F-actin, the main component of desmosome-like contacts, has been suggested to be responsible for the increased resistance of M-cells to LDS. The purpose of the present study was to investigate the capacity of M-cells to adapt to LDS under the influence of ethanol, which alters the content of F-actin in cells. The experiments were carried out in goldfish fry. Vestibular stimulation (training and LDS) was performed in special drums that were rotated in two planes. The training time was increased from 1 min on day 1 to 30 min on day 30. For ethanol exposure, fish were immersed daily in a 2% ethanol solution for 20 min. To assess the level of resistance to LDS, motor activity indicating the functional state of M-cells was evaluated before and after LDS. The results show that exposure to ethanol reduces the resistance to LDS in both untrained and trained fish. Electron microscopic data demonstrated some structural changes in the synaptic endings located on M-cell soma in ethanol-exposed fish. Wrapping of boutons by cytoplasmic out- growths and myelin- like structures was observed. Morphometric analysis revealed that exposure to ethanol without training decreases the number of desmosome-like contacts, probably due to ethanol-induced depolymerization of cytoskeletal actin. Ethanol exposure also partly suppressed the increase in the number of desmosome-like contacts that occurs as a result of training. In ethanol-treated trained fish, however, a concomitant increase in the length of desmosome-like contacts was observed. As training alone leads to the formation of additional desmosome-like contacts of standard length, it is possible that although a sufficient amount of such structures cannot be formed in the M-cells of ethanol-exposed trained fish, the existing contacts can be elongated. Thus, possibly changes of the actin state are involved in the adaptation of M-cells to LDS.

Devices for testing tablets with respect to abrasion strength and dissolution rate

120 be not less that 97%. No abrasion testing is stipulated for the coated tablets. The standard procedure for determination of the abrasion strength of tablets [ i ] involves rotation of tablets in a special drum and monitoring of the amount of powder formed as a result of mechanical interactions of the tablets with each other and with the drum elements. The pre-existing standard device for the abrasionstrength testing of tablets was recently improved at the Progress Company and is now available in the modified variant. Figure l shows a general outline of the tablet testing device of the UPI type (Russian technical standard TU 9471012-05749470 95). The testing device comprises an electromechanical unit and two drums. The electromechanical unit rotates the drums with tested tablets at a controlled speed and provides necessary supply voltages for the electronic circuit. The front panel of the electromechanical unit contains the following controls: "Power o n o f f " tumbler and the indicator lamp "Mains"; "Time" multiposition switch for selecting the drum rotation time from 1 to 30 min; "Start" button initiating the drum rotation. The rear panel of the electromechanical unit contains the elements of mains connections. The drums are cylinders provided with removable lids. The testing procedure is as follows. According to [ 1 ], ten tablets, cleaned from loose species and weighed with an accuracy of 0.001 g, are placed into the drum and treated for a 5-min time period. When the drum is stopped, the tablets are extracted, cleaned of powdered material, and weighed again to within 0.001 g. The abrasion strength is calculated by the formula

EFFECTS OF GYPSUM ON THE NEUTRON PROBE CALIBRATION CURVE

The variation of percent gypsum with depth in gypsiferous soils requires a special calibration curve for each layer in order to obtain accurate results in soil-water studies using a neutron probe. To overcome the tedious work of the field calibration for each layer, a correction factor for percent gypsum and bulk density was suggested. The effects of gypsum and bulk density on the neutron probe calibration curve were studied in the laboratory, using a special drum that can be bolted together in two halves, and in the field. The effect of bulk density determined on core samples was negligible for the soil studied in the laboratory, whereas it was significant for one of the field calibrations carried out on gypsiferous soils. An increase in the slope of moisture content on a volume basis vs. count ratio with increasing gypsum content determined by precipitation with acetone method of the soil was observed in the laboratory calibration. A simple method for correction of the calibration curve for gypsum content was adopted to obtain a specific curve for each layer. The adopted method requires the hypsum fraction to be estimated for each layer and then incorporated in the calibration curve to improve themore » coefficient of determination. The field calibrations showed improvements of the determination coefficient by introducing hypsum fraction, calcium carbonate fraction determined by the calcimeter, and bulk density in one calibration in addition to count ratio using moisture content on a volume basis as a dependent variable in multilinear regression analysis. The presence of gypsum in the soil increases count ratio in that some of the water is water of hydration, unavailable to plants. The effect of bulk density is not as clear in the case of organic soils and when hydrogen exists in the soil in forms other than free water. 13 refs., 4 figs., 3 tabs.« less

Practical evaluation of some coal-cutting theories using a continuous miner : Roxborough, F F; Pedroncelli, E J Min Engr, V142, N252, Sept 1982, P145–156

As part of a major research programme in coalface mechanization, the South African Chamber of Mines has undertaken a comprehensive series of experiments in coal cutting using a Lee-Norse machine equipped with a special drum allowing four different levels of pick spacing, 50, 100, 150, and 200 mm to be investigated. Other modifications were made to the machine so that it could cut at drum speeds of 42, 35, 15 and 7 rpm and generate a much higher than normal sumping and shearing force capability at the cutting drum. The results of these experiments have shown that cutting efficiency improves markedly when operating at a large depth of cut, and that the optimum spacing for picks is between one and two times the depth of cut. This conforms well with laboratory and theoretical findings. However, the point-attack pick, which previously has been critized as an inefficient tool, was found in practice to be somewhat more efficient than the chisel-shaped pick at larger depths of cut, although its performance was generally inferior at shallow depths. (12 refs.)

Programmed "trendscription." A new approach to electrocardiographic monitoring.

A new approach to monitoring of episodic but frequently recurring arrhythmias has been developed, consisting of condensation of electrocardiographic information on a special drum recorder, a programmer that permits selection of intervals and durations for monitoring, and a telemetry unit for transmission of the electrocardiographic signal. We used this system to manage three selected cases.

Programmed "Trendscription"

A new approach to monitoring of episodic but frequently recurring arrhythmias has been developed, consisting of condensation of electrocardiographic information on a special drum recorder, a programmer that permits selection of intervals and durations for monitoring, and a telemetry unit for transmission of the electrocardiographic signal. We used this system to manage three selected cases. (JAMA232:39-43, 1975)

Rating of bare overhead conductors for continuous currents

The maximum continuous rating of a short transmission line is often based on the maximum permissible operating temperature of the conductors under the combined effects of wind, sun and air temperature. The paper describes measurements made in still air and in four different wind tunnels to determine the heat transfer from stranded-copper, aluminium, aluminium-alloy and steel-cored-aluminium (s.c.a. or a.c.s.r.) conductors. For Reynolds numbers (Re) between 100 and 3000, the heat transfer was very close to that for smooth circular cylinders of equal overall diameters, but for 3000 < (Re) < 50000, it was higher, the difference increasing with surface roughness. The heat transfer decreased with decreasing angle of attack of the wind relative to the axis of the conductor. Turbulence generated by the windward conductors of a bundle resulted in higher heat transfers for the leeward conductors. The effective radial thermal conductivity may be calculated from the radial temperature gradient, and typical values are given. Measurements of the absorption of solar heat by conductors mounted in a special drum are also described. Equations are given for calculating the continuous rating of conductors exposed to various atmospheric conditions.

Rational Design of Hoisting Drums

Abstract The main problem of hoisting-drum design resolves itself into two parts: determination of flange shape and thickness, and determination of the thickness of the drum body. Other factors, such as brake, clutch, and bearings, have already been investigated and are therefore not considered in this paper. The correct proportioning of drum flanges is obviously dependent upon the side pressure brought to bear against them, by the coils of rope wound about the drum. In other words, flange thickness is a function of (a) rope tension and (b) depth of winding. Previous theoretical investigations have recognized these factors, but have failed to take account of the friction between adjacent coils of rope, and between rope and drum, which tends to hold the coils in position without the aid of the flanges, and have also disregarded the flattening of the inside coils under pressure from the outer layers. This flattening, which is quite appreciable on account of the soft core of hoisting rope, results in a shortening of the inner coils, thereby relieving them of a part of their tension, and reducing the pressure against the flanges. A theoretical formula is deduced for the total pressure against a drum flange caused by the winding-on of rope to a given depth and under a given initial tension. Two other formulœ are then deduced, which relate this total pressure to the flange thickness and the maximum allowable tensile and shearing stresses in the material. By means of these formulæ a flange of the usual straight-sided or the mushroom type may be designed to withstand safely the pressure of the rope wound upon the drum. The drum body is subjected to combined stresses, since it is under compression from the coils wound upon it, under tension due to the lateral pressure against the flanges, and under combined torsion and bending caused by the load which is to be hoisted. Formulæ are derived which may be used to obtain the correct thickness both at the center of the drum, where the normal stresses are greatest, and at the ends of the drum, where the shearing stresses are most prominent. In order to check the theoretical formula for flange pressure, tests were made with small-size rope wound upon a special drum, which was so arranged that the side thrust against one flange could be directly measured while the rope was being wound on or unwound. These tests show conclusively that formulæ for flange pressure which do not take account of rope friction and flattening give excessively large results.