Drum Load Research Articles

Modeling of mechanical treatment of napiform onion to determine the rational parameters of its cleaning

In order to improve quality of the process of cleaning vegetable raw materials, development of new equipment is necessary, which will allow processing different kinds of raw materials and manufacturing products with stable quality indicators. When designing new equipment, it is necessary to take into account that the new machinery should have compact dimensions, be versatile and multioperational. This will make it possible to successfully compete in the domestic and international markets. We designed an experimental installation with appropriate methodology that allows studying the process of cleaning napiform onion with the capacity to determine the impact of all its parameters on the percentage of loss of raw materials and efficiency of cleaning the product. This is provided for by the presence of a working drum that rotates around its axis in an experimental set-up. The rotation frequency may be changed in the required range. The working drum has at its surface special openings for cutting inedible part of the bulbs. A mathematical model of treating napiform onion during cleaning was obtained. Mathematical model takes the form of a system of inequalities, which links the coefficient of filling the drum and central angle of the segment with product. The model proves that the optimal mode of motion of the product in the drum device for cleaning is the mode under which a layer of bulbs lose equilibrium state and there occur sliding forces relative to the inner surface of the drum, which, together with the force of friction, determine the effort for cutting the neck and stem of a bulb. We received equations to calculate the limiting modes of motion when moving in the drum, which explicitly take into account the friction coefficient, angle of natural bevel of the layer of product and the magnitude of drum load. It was established that the maximum value of degree of cleaning the bulbs is 88…98 %. Mathematical modeling of the process of mechanical treatment of napiform onion allows us to determine rational parameters of the combined process of its cleaning. These parameters include rotation frequency of the working drum, load factor of the working chamber and the shape of openings in the working drum. On the basis of the conducted theoretical and experimental research, we designed a device for the combined cleaning of napiform onion. The device allows thermal pre-treatment of raw materials with the aim of weakening the bond between husk and a bulb. Subsequent mechanical treatment, which is also implemented in the device, provides complete cleaning of the product from husk.

STOCHASTIC ANALYSIS TO ASSESS THE PERFORMANCE OF PELTON WHEEL TEST RIG KEEPING SPEED CONSTANT

Hydraulic Turbines are being used since the ancient times to harness the energy stored in flowing streams, rivers and lakes. The oldest and the simplest form of a hydraulic turbine was the waterwheel used for grinding grains. The basic idea of a Pelton Wheel Turbine is derived from this ancient waterwheel. Pelton wheel is the only hydraulic turbine of the impulse type in common use. It is named after the American engineer Laster A. Pelton, who contributed much to its development around the year 1880. Therefore, this machine is known as Pelton Turbine or Pelton Wheel. Pelton Wheels are the preferred turbine for hydro-power when the available water source has relatively high hydraulic head at low flow rates. In the present study, a complete analysis of the Pelton Wheel Test Rig with brake drum loading made available on college campus is carried out. The major input and output parameters along with their working ranges are identified. Stochastic analysis using Monte Carlo’s simulation is carried out by randomly generating a design matrix and thus calculating the responses using predetermined equations. Response Surface Methodology is adapted to identify the optimal set of inputs and also generate inputoutput relations. Furthermore, a design matrix is generated by taking practical readings on the Test Rig keeping speed constant and the respective outputs are calculated. Similar to the stochastic study, Response Surface Methodology is adapted by inputting the design matrix in a design expert software. Input-output relations are generated and also the optimal set of input parameters are determined using this software.

Research on the effect of dip angle in mining direction on drum loading performance: a discrete element method

Poor performance in coal loading of thin coal shearer is the main reason affecting thin coal mining efficiency. In the paper, the development of thin coal shearer coal loading performance was summarized and the lack of the related researches was pointed out. According to the working features of dip angle of thin coal shearer at the different working faces, a simplified model of drum coal loading was set up. The influence rules of dip angle on drum pushing and drum ejection coal loading performance were studied by discrete element method (DEM) simulations and the prime factors of drum coal loading rate significantly influenced by dip angle were identified. In addition, according to the poor drum coal loading rate, the improvement suggestions were proposed, and verified through DEM simulation.

Analysis of large-scale tablet coating: Modeling, simulation and experiments

This work concerns a tablet coating process in an industrial-scale drum coater. We set up a full-scale Design of Simulation Experiment (DoSE) using the Discrete Element Method (DEM) to investigate the influence of various process parameters (the spray rate, the number of nozzles, the rotation rate and the drum load) on the coefficient of inter-tablet coating variation (cv,inter). The coater was filled with up to 290kg of material, which is equivalent to 1,028,369 tablets. To mimic the tablet shape, the glued sphere approach was followed, and each modeled tablet consisted of eight spheres. We simulated the process via the eXtended Particle System (XPS), proving that it is possible to accurately simulate the tablet coating process on the industrial scale. The process time required to reach a uniform tablet coating was extrapolated based on the simulated data and was in good agreement with experimental results.The results are provided at various levels of details, from thorough investigation of the influence that the process parameters have on the cv,inter and the amount of tablets that visit the spray zone during the simulated 90s to the velocity in the spray zone and the spray and bed cycle time. It was found that increasing the number of nozzles and decreasing the spray rate had the highest influence on the cv,inter. Although increasing the drum load and the rotation rate increased the tablet velocity, it did not have a relevant influence on the cv,inter and the process time.

Solids holdup in flighted rotating drums: An experimental and simulation study

Directly heated rotary dryers are widely used in various industries and have been the subject of numerous studies. However, few studies have focused on the behavior of particle dynamics in these dryers, and most of them are still designed based on empirical data and pilot plant scale-ups. This paper reports on a study of the effect of operating conditions on solids flow in rotating dryers. The holdup of solids in the flights was modeled using the Eulerian Granular Multiphase Model and the results were compared with experimental data, using a methodology created specifically for this purpose. The influence of particle diameter, type of material, rotation speeds and drum loading on solids holdup in the flighted rotating drum has been analyzed. The results of the present work have shown that the Eulerian approach has been able to predict the fluid dynamics behavior of different solid materials in several operating conditions. Despite the deviations between predicted and measured results, this approach allows the development of a “more” generalized model, with “low” computational cost.

Understanding the Agglomeration Behavior of Selected Copper Ores Using Statistical Design of Experiments

The drum agglomeration of two different crushed copper ores (I and II) has been optimized using Taguchi's L16 (45) orthogonal array design to determine the optimum conditions for maximizing the average agglomerate size and minimizing the amount of fines. The effects of controllable operating factors including moisture content (ore I: 9.6–11.1%; ore II: 12.8–14%), retention time (2–4 min), drum speed (15–45% critical), drum load (ore I: 13–32%; ore II: 6–24%) and acid concentration (6.5–90 g/L) on the performance of the agglomeration process were studied. For ore I, the maximum average agglomerate size and minimum percent fines (−1 mm) occurred under the conditions: drum load (22.75%), moisture (10.35%), time (4 min), drum speed (30% critical), and acid concentration (41 g/L), whereas for ore II, the same conditions occurred under the drum load (18%), moisture (13%), time (3 min), drum speed (30% critical), and acid concentration (30 g/L). Under the conditions studied for ore I, the most effective parameter for maximizing average agglomerate size and minimizing the amount of fines was found to be drum load. For ore I, time and acid concentration had a measurable effect on maximizing average agglomerate size, whereas moisture had a statistically significant effect on minimizing the amount of fines. For ore II, the most effective parameter for maximizing average agglomerate size and minimizing the amount of fines was found to be acid concentration. Time had a measurable effect on maximizing average agglomerate size, whereas the other variables did not affect the responses significantly for ore II.

Evaluation of critical process parameters for inter-tablet coating uniformity of active-coated GITS using Terahertz Pulsed Imaging

The aim of this study was the evaluation of critical process parameters (CPP) for inter-tablet coating uniformity in an active pan coating process using nondestructive Terahertz Pulsed Imaging (TPI). Coating uniformity was assessed by calculating the coefficient of variation (CV) of coating thickness measured by TPI, and the CV of API content measured by high performance liquid chromatography (HPLC). A design of experiments (DoE) was performed at pilot scale with drum load, drum speed, spray rate, run duration and spray pressure as factors. Good agreement in the CV of both analytical techniques was shown. The DoE models both revealed the same CPP: a low drum load, high drum speed, low spray rate and high run duration were beneficial for coating uniformity. The spray pressure was only significant in one of the DoE models. It was further shown that the negative impact of a high drum load on the CV cannot only be compensated by high drum speed, but also be compensated by a low spray rate and long run duration. It was demonstrated that TPI is a feasible tool for the measurement of inter-tablet coating uniformity and for the evaluation of CPP in an active pan coating process.

Understanding the agglomeration behavior of nickel laterite and gold ores using statistical design of experiments

The drum agglomeration of nickel laterite and gold ores has been optimized through the design of experiments (DOE) using a Taguchi L16 (4 5 ) orthogonal array to determine the optimum conditions for maximizing average agglomerate size and minimizing the amount of fines. The effects of controllable operating factors including moisture content (nickel laterite ore: 34-37%; gold ore: 7-10%), retention time (2-3.5 min), drum speed (15-45% critical speed), drum load (nickel laterite ore: 8-32 %; gold ore: 6-22%) and acid concentration (150-600 g/L) on the performance of the agglomeration process were studied. For nickel laterite ore, maximum average agglomerate size and minimum percent fines (-1 mm) occurred under the following conditions: drum load (23.7%), moisture (36.5%), time (3 min), drum speed (30% critical speed) and acid concentration (150 g/L). Under the studied nickel laterite ore conditions, the most effective parameters for maximizing average agglomerate size and minimizing the amount of fines were found to be drum load and acid concentration, respectively. Drum speed had a statistically significant effect on minimizing the amount of fines. Maximum average agglomerate size and minimum percent fines (-1 mm) for gold ore occurred under the following conditions: drum load (19.3%), moisture (8.5%), time (2 min 15 s) and drum speed (40% critical). The most significant factors for maximizing average agglomerate size and minimizing the amount of fines for gold ore were found to be drum load, time and moisture.

Fatigue behaviour of coke drum materials under thermal-mechanical cyclic loading

Coke drums are vertical pressure vessels used in the delayed coking process in petroleum refineries. Significant temperature variation during the delayed coking process causes damage in coke drums in the form of bulging and cracking. There were some studies on the fatigue life estimation for the coke drums, but most of them were based on strain-fatigue life curves at constant temperatures, which do not consider simultaneous cyclic temperature and mechanical loading conditions. In this study, a fatigue testing system is successfully developed to allow performing thermal-mechanical fatigue (TMF) test similar to the coke drum loading condition. Two commonly used base and one clad materials of coke drums are then experimentally investigated. In addition, a comparative study between isothermal and TMF lives of these materials is conducted. The experimental findings lead to better understanding of the damage mechanisms occurring in coke drums and more accurate prediction of fatigue life of coke drum materials.

Evaluation of critical process parameters for intra-tablet coating uniformity using terahertz pulsed imaging

The purpose of this study was to evaluate the intra-tablet coating uniformity and the identification of critical process parameters in an active pan coating process using terahertz pulsed imaging (TPI). A design of experiments (DoE) was performed with drum load, drum speed, spray rate, run duration and spray pressure as factors. Different measures of intra-tablet uniformity were investigated: the average thickness on the individual tablet faces, spatial variation in layer thickness over the tablet surface, and the coefficient of variation (CVintra). Data analysis revealed that the process parameters in the investigated parameter space had hardly any influence on the difference in layer thickness of the tablet faces and centre band. No increase or decrease in layer thickness – as described in the literature – was found towards the edges of the tablet face. In overwetted process conditions a higher layer thickness at the centre band edges could be observed. Still, the highest variability in coating thickness was found along the circumference of the centre band rather than the height. In general, higher CVintra of layer thickness were found on the centre bands in comparison with the tablet faces. The analysis of the DoE model revealed that the run duration had the highest influence on the CVintra on the tablet faces. TPI showed high potential in the assessment of intra-tablet uniformity and layer thickness distributions over the whole tablet surface. It was successfully used to identify critical process parameters regarding intra-tablet coating uniformity.

Development of Hand-Operated Mechanical Ginger Peeler

Ginger, an underground rhizome, is valued as a spice and is used in both dry and fresh form. The process of peeling is labour-intensive and is a time-consuming operation in post-harvest handling of ginger done manually by women labour. To reduce time and labour requirement, a mechanical ginger peeler having a square mesh drum was developed. Peeling trials were conducted for varying drum loads (6kg, 8kg and 10kg), varying drum speeds (35rpm, 40rpm and 45rpm) and for different peeling durations (5 min, 10 min and 15 min). Optimum machine parameters for maximum efficiency were: drum load of 8 kg per batch, operated at drum speed of 40rpm for peeling duration 15 min. Peeling efficiency and material loss at optimum conditions were determined to be 55.60% and 4.68%, respectively. Dry ginger obtained after mechanical peeling was found to contain essential oil at 2%, oleoresin 4.6%, moisture content 9.82% and crude fibre content 2.5%.

Parameters analysis of shearer drum loading performance

Three drums with different helical angles (15°, 20°, and 25°) were developed to investigate improved loading performance of the shearer drum. Nine trials were performed at different drum rotation speeds (80, 100, and 120 r/min) and different haulage speeds (1.5, 2.0, and 2.5 m/min) in an orthogonal test design. Loaded coal quantity and cutting power of the drum were the responses measured under the different conditions. The effect of the parameters was determined by means of the extreme difference method. The significance of the effects was determined by analysis of variance. The results indicate that the effect from changes in the helical vane on loading performance of the drum is the largest in magnitude. The haulage speed has the least affect on loading performance. The helical angle has the least affect on cutting power of the drum. Haulage speed has the largest affect on the cutting power of the drum.

A photometric analysis of tablet movement in a side-vented perforated drum (Accela-Cota)

A novel particle tracing technique has been used to study the effect of the normal process variables i.e. drum speed, drum loading and the presence/absence of mixing elements (baffles) on the movement of tablets in a side-vented perforated drum (24 in diameter Accela-Cota). The technique involves measuring the duration of light emission from a single luminous tablet using a photomultiplier mounted to scan the same area as a spray gun, and has enabled the quantification of both the time that the tablet spends on the surface per pass (surface time) and the time that the tablet spends within the bulk of the tablet bed (circulation time) over run lengths equating to the normal tablet coating cycle. The technique also allows the study of the uniformity of tablet appearances by means of circulation profiles. It was found that, while both the surface and circulation times decreased with increasing drum speed and loading, there was irregularity of tablet appearance especially at low drum speeds and in the absence of baffles.

Study on pick arrangement of shearer drum based on load fluctuation

Abstract According to the coal or rock cutting theory, a mechanical model and computing formula for a pick and the drum load fluctuation model were established in order to obtain relationships between pick arrangements and drum fluctuation loads, drum rotary speeds and haulage speeds. Based on a minimum load fluctuation, an optimal mathematical model was established for drum pick arrangements. The effects of pick arrangements (including punnett square, sequence, aberrance I and II) on the drum load fluctuation coefficient are discussed. The relationships between the pick arrangements of the drum with different start vanes and the cutting load fluctuation coefficient, the drum rotary speed and haulage speed were also studied. The results indicate that the punnett square arrangement has a smaller cutting load fluctuation coefficient than other forms of arrangement and the drum with the 4-start vanes has the smallest coefficient. The drum rotary speed and haulage speed are affected not only by pick arrangements, but also by the number of vanes.

Experimental studies on distributions of granule size, binder content and porosity in batch drum granulation: Inferences on process modelling requirements and process sensitivities

Batch granulation experiments on a lab-scale drum granulator for a Calcite/Polyvinyl alcohol in water (Calcite/PVOH–H 2O) system are presented in this study. Experimental studies were carried out to study the aggregation kinetics and mechanism for this granulation recipe, whilst investigating the effects of binder-to-solids ratio and drum load on the granule size, binder content and porosity distributions. In particular, the effect of formulation properties and the granulation operating conditions on the batch process dynamics and the end-granule properties are studied. The formulation properties considered include liquid surface tension, powder-liquid contact angle, dynamic yield stress, powder shape and liquid viscosity. The operating variables include the binder-to-solids ratio, binder addition duration and the binder addition mode. The sensitivity in the process and the non-homogeneity of key particle attributes (size, binder content, and porosity) is evident. The important process manipulations for feedback control and potential disturbances are identified, formulating a comprehensive control configuration for batch and continuous granulation, with the latter case being exemplified in Glaser et al. [T., Glaser, C.F.W., Sanders, F.Y., Wang, I.T., Cameron, R., Ramachandran, J.D., Litster, J.M.-H., Poon, C.D., Immanuel, F.J. Doyle, III, 2007. Model predictive control of drum granulation. Manuscript in preparation.]. The importance of multi-scale process models that link fundamental material properties with the granulation mechanisms and end-granule properties is also evident from the experiments. A three-dimensional population balance equation structure in terms of the particle size, binder content and porosity is confirmed to be an ideal framework for the process model.

Solubility characterization of airborne uranium from an in situ uranium processing plant.

Solubility profiles of uranium dusts in the Irigaray uranium processing plant were determined by performing in vitro solubility tests on breathing zone air samples conducted in all process areas of the processing plant. The dissolution rate of the uranium on the air samples was then determined over the next 28 d in a simulant solution of the extracellular airway lining fluid (Gamble's solution). Airborne uranium in the wet process areas of the processing plant was highly soluble, with 97% dissolving in a 0.3 d half-time and 3% with a half-time of 15.6 d. The airborne uranium dusts in the drum load out area were also soluble, with 97% dissolving with a T1/2 of 0.25 d and the remainder with a T1/2 of 20 d. Exhaust from the drier stack and areas of the processing plant that had only this airborne uranium was slightly more insoluble, with 46% dissolving with a T1/2 of 0.4 d and 53% with an 18 d half-time. These results compare well with x-ray diffraction analysis of the uranium samples and the bioassay program for the processing plant workers.

High-density magnetic tape recording by non-tracking method

Conventional helical-scan magnetic recording requires precise head tracking, precise tape path and accurate servo control. We have developed a magnetic tape recording system based on a new concept, the ‘non-tracking method’, which requires less accuracy. By combining double density track scanning and data rearrangement through a memory device, all data can be reproduced in correct order without precise head tracking. When the track pitch is 9.8 μm, the non-tracking method expands the tolerance on head tracking to ±100 μm, while the head tracking tolerance of ±5 μm is needed in conventional recording. Using the non-tracking method, a newly developed rotary head drum loading system called ‘non-loading’ and also a newly developed metal-evaporated tape, we have developed an extremely high density digital audio tape recording system, including a stamp-sized tape cassette and a miniature digital audio recorder. Two hours stereo digital recording is achieved with the small cassette.

High Density Magnetic Tape Recording by Non-Tracking Method

Conventional helical-scan magnetic recording requires precise head tracking, precise tape path and accurate servo control for them. We have developed a magnetic tape recording system based on a new concept, "Non-tracking Method" which requires less accuracy of them. By combining double track scanning and data rearrangement through a memory divice, all data can be reproduced in correct order without precise head tracking. When track pitch is 9.8μm, the non-tracking method expands the tolerance on head tracking to plus and minus 100μm, while the head tracking tolerance of plus and minus 5μm is needed in conventional recording. Using the non-tracking method, a newly developed rotary head drum loading system which is called "non-tape-loading" and also a newly developed metal-evaporated tape, we have developed a extremely high density digital audio tape recording system, including a stamp-sized tape cassette and a tiny digital audio recorder. Two hours stereo digital recording is realized with the tiny cassette.

Saturation Estimation In Interactive Computer Systems

AbstractThis paper presents a systematic method for estimating the saturation point of interactive computer systems in an environment of incomplete information (in particular, where per interaction information is unavailable). This method is an improvement over the ad hoc, highly subjective, and time-consuming iterative approach commonly used. Following an operational analysis approach and using only commonly available data, a simple model was constructed to estimate the mean response time of a task characterized by its ci’u and I/O requests running in a given level of system load. The system work load is characterized by the CPU, disk, drum, and channel load factors. The system is periodically measured (or the system log examined) to obtain the parameter values needed to estimate the mean response time ofthe task as well as the corresponding work load level. With sufficient samples, a mean response time vs. system load curve can be plotted. The system saturation load is taken to be that corresponding to ...

A hybrid processor for modifying and rearranging radionuclide scan data under direct observation.

INTERPRETATION of radionuclide scan data is still a qualitative and descriptive procedure, but quantitative relationships of scan data are becoming more important. As a consequence, there is a trend of interest toward using automatic computation methods in this field. Since even the simplest scan picture is made up of an enormous amount of data, it is natural to apply the digital computer to these problems, for this instrument characteristically can store large amounts of data and process them rapidly according to instructions (3–5). The potential value of digital computation in scanning is just unfolding. Special emphasis has been given to improving picture quality by smoothing random fluctuations in count (4, 6–8), correcting for distortions in resolution (9, 10), subtracting one picture from another (4, 11), or adding counts representing selected structures in a picture or series of pictures for either statistical analysis or quantification of the time course of radiopharmaceutical in an organ (11–13). These applications are useful for specific practical problems in scanning, but their greatest significance now is in establishing and clarifying the basic principles of the method. The general requirements for a scan processor are that it permit nondestructive storage of the data and have provision for modifying and displaying these data subsequently in flexible ways so that they can be used more effectively. The generalpurpose digital computer, in its most common form, has special disadvantages when applied to image data; communication between computing equipment and the physician is inadequate, batch processing is restrictive, and the printed matrix of symbols is ineffective for visualization. This is a report of a hybrid system we developed to avoid these restrictions. It is a combination of digital processor (Figure 1, A) and analogue cathode-raytube (CRT) display (Figure 1, B), matched so that each is used to best advantage. Our processor for scan data is designed to provide for a wide and flexible range of data operations, direct picture display on a CRT screen in grey-shade and other picture formats, and full operator control of both processing and display operations at the time of viewing. The instrument does not require the user to learn complicated programming schemes. The operator is expected to be a physician who controls the parameters of interest by punching preset buttons on a keyboard while observing changes displayed on a CRT screen. The instrument is intended to serve as a central processor and reader for data from several scanning units. The System A. Drum Loading At the time of scanning, counts detected during each predetermined spatial interval of detector displacement are recorded in 6-bit binary code on standard 8-column perforated paper tape, along with position codes (TABLE I) (14).