Drum Surface Research Articles

Impact of axial segregation characteristics on the particle collision energy in rotating drums

The particle mixture in rotating drums is not always in a completely mixed state, resulting in a complex relationship between the particle mixing and segregation characteristics and the overall collision energy. Based on existing experimental validation, the rotary drums with axial adjacent segments are numerically simulated via the discrete element method to investigate the axial segregation mechanism of the particle mixtures in rotary drums. The results show that the rotational direction of the adjacent axial segments changes the axial flow configuration, resulting in a transformation of the overall particle mixing and segregation characteristics. Based on the proposed novel relative regional total energy (RRTE) index, this work further evaluates the impact of the axial segregation characteristics on the collision energy of binary and ternary particle mixtures within rotary drums. The axial segregation phenomenon makes the RRTE of each radial surface inconsistent, resulting in difficultly reflecting the particle collision energy through the individual radial surface. Compared with the radial drum surface, the RRTE represented by the axial surface can better reflect the particle collision energy in rotating drums. In summary, the more obvious the presence of axial segregation characteristics in rotary drums, the lower the total collision energy used for overall grinding process of the media and abrasive particles.

Monte Carlo simulation of shielding materials in storage drums for 241Am-Be disused sealed radioactive sources

Disused Sealed Radioactive Sources (DSRS) containing neutron sources such as 241Am-Be require careful management due to neutron radiation. However, finding readily available and effective combination layer shielding materials for practical use to safely contain 241Am-Be can be challenging. The main objective of this study is to investigate the configuration of shielding materials and determine the maximum activity of 241Am-Be sources that can be safely stored in a 200-L drum. A three-layer shielding approach using a 200-L drum as a storage container, with sequential layers of lead (Pb), polyethylene (PE), and ordinary Portland concrete (OPC), achieves the lowest dose rates compared to other combination sequences, as shown by Monte Carlo simulations. With a fixed lead thickness and varying polyethylene and ordinary Portland concrete thicknesses, Monte Carlo simulations using the Particle and Heavy Ion Transport code System (PHITS) demonstrate that this drum design can safely accommodate activities ranging from 22.01 Ci to 72.92 Ci of 241Am-Be. The fitted model equation determines the required polyethylene thickness for any activity within this range. Additionally, case-based simulation results indicate that Indonesia's total inventory of 241Am-Be DSRS can be stored in three 200-L drums with a polyethylene thickness of 15 cm. This configuration meets international standards, ensuring the dose rate does not exceed 2 mSv/h at the surface and 0.1 mSv/h at 1 m from the drum's surface.

Dependence of drying rate on interfacial thermal contact conductance in drum drying of thin materials

Drum dryers are widely employed in various industrial fields for their remarkable capability to efficiently dry thin porous materials such as textiles and paper. The heat transfer process in drum drying involves an interaction between the drum surface and the materials being dried. However, measuring interfacial thermal contact conductance during drum drying is very challenging, and little data has been reported in the literature. It is therefore unclear how changes in interfacial thermal contact conductance quantitatively affect drum drying in terms of drying time. We created an innovative laboratory-scale experimental setup designed to measure changes in moisture content of textiles at various contact pressures during drum drying. By combining our experiments with a simple yet effective heat transfer model, we were able to quantify the impact of interfacial thermal contact resistance on drying time. Specifically, in drying tests using thin cotton textiles, the experimental results revealed that when the contact pressure was increased from 120 Pa to 480 Pa, the thermal contact conductance increased by approximately 30% and the drying time decreased by approximately 20%. The outcomes of our study significantly advance the current understanding of drum drying processes and reveal vital insights into techniques for optimizing energy consumption.

Investigation on the roller-pavement interaction and asphalt pavement compactness based on marginal spectrum of vibration signal energy

Compaction is a critical assurance for the quality and performance of asphalt pavement in terms of durability and serviceability. At present, there is a knowledge gap in the roller-pavement interaction in terms of energy variation during the process of asphalt pavement compaction. This paper aims to reveal the interaction and energy variation between the vibrating drum and pavement surface course during compaction process. Based on field tests, vibration signals of both the vibrating drum and pavement (i.e., the top, middle and bottom surface layers) were captured by acceleration sensors, and then the Hilbert marginal spectrum of the signals was obtained by the Hilbert-Huang Transform (HHT) for interpreting the signal features. Based on the marginal spectrum, the energy variation of the vibrating system (drum and pavement) during compaction was obtained. A predictive model of pavement compactness was further established according to the observed linear relationships between the pavement compactness and the energies of the vibrating system, and was then validated in the field application. The findings show that the energy-based approach adopted herein is able to not only characterize the compactness of asphalt pavement, but also reflect the uniformity of compaction. The developed relationships have a good potential as a useful tool for quality control in the field compaction practice.

On Drum Brake Squeal—Assessment of Damping Measures by Time Series Data Analysis of Dynamometer Tests and Complex Eigenvalue Analyses

Brake squeal—an audible high-frequency noise phenomenon in the range between 1 kHz and 15 kHz resulting from self-excited vibrations—is one of the main cost drivers while developing brake systems. Increasing damping is often a crucial factor in the context of self-excited vibrations. Countermeasures applied for preventing brake squeal have been investigated particularly for disk brakes in the past. However, in recent years, drum brakes have once again become more important, partly because of the issue of particle emissions. Concerning noise problems, drum brakes have a decisive advantage compared to disk brake systems in that the outer drum surface is freely accessible for applying damping devices. This paper focuses on the fundamental proving and evaluation of passive damping measures on a simplex drum brake system. To obtain a detailed understanding of the influence of additional damping on the squealing behavior of drum brakes, extensive experimental investigations are performed on a brake with an intentionally introduced high squealing tendency in the initial configuration. This made it possible to investigate the influence of different types of damping measures on their effectiveness. Techniques from the field of big data analysis and machine learning are tested to detect squeal in measured time series data. These techniques were remarkably reliable and made it possible to detect squeal efficiently even in data that was not generated on a traditional costly NVH brake dynamometer. To investigate whether the simulation method usually used for the simulation of brake squeal is applicable to depicting the influence of additional damping in drum brakes, a complex eigenvalue analysis was performed with Abaqus, and the results were compared with those from the experiments.

Large-scale assembly of isotropic nanofiber aerogels based on columnar-equiaxed crystal transition

Ice-templating technology holds great potential to construct industrial porous materials from nanometers to the macroscopic scale for tailoring thermal, electronic, or acoustic transport. Herein, we describe a general ice-templating technology through freezing the material on a rotating cryogenic drum surface, crushing it, and then re-casting the nanofiber slurry. Through decoupling the ice nucleation and growth processes, we achieved the columnar-equiaxed crystal transition in the freezing procedure. The highly random stacking and integrating of equiaxed ice crystals can organize nanofibers into thousands of repeating microscale units with a tortuous channel topology. Owing to the spatially well-defined isotropic structure, the obtained Al2O3·SiO2 nanofiber aerogels exhibit ultralow thermal conductivity, superelasticity, good damage tolerance, and fatigue resistance. These features, together with their natural stability up to 1200 °C, make them highly robust for thermal insulation under extreme thermomechanical environments. Cascading thermal runaway propagation in a high-capacity lithium-ion battery module consisting of LiNi0.8Co0.1Mn0.1O2 cathode, with ultrahigh thermal shock power of 215 kW, can be completely prevented by a thin nanofiber aerogel layer. These findings not only establish a general production route for nanomaterial assemblies that is conventionally challenging, but also demonstrate a high-energy-density battery module configuration with a high safety standard that is critical for practical applications.

Laboratory Machine Verification of Force Transmission Provided by Friction Acting on the Drive Drum of a Conveyor Belt

The paper presents the measured values of tensile forces acting on transmission idlers in the upper and lower run of a conveyor belt placed on a laboratory machine designed at the Department of Machine and Industrial Design, Faculty of Mechanical Engineering, VSB-Technical University of Ostrava. The tensile forces detected by two strain gauge load cells and recorded using DEWESoft software were used to calculate the friction coefficient, which acts on the surface of the driving drum casing and the conveyor belt. The friction coefficient at the slip point, or during the slippage of the conveyor belt on the rubber or steel casing of the driving drum, was determined for two states of the surfaces that are in contact. Experimental measurements on a laboratory machine determined four values of friction coefficients for two types of drum surfaces and for two states of contact surfaces, which were compared with the recommended standard values. The measured values reached higher values in comparison with the values given by the CSN standards. The highest deviation of 273.3% is achieved using a steel wet surface, and the lowest deviation of 106.3% is achieved when using a rubber dry lining for the driving drum casing. On the presented laboratory machine, it is possible to measure tensile forces for different speeds of movement, different belt angles on the driving drum, various types of belt surfaces, different types of drum casing linings, and different sizes of tension forces for the endless loop of the conveyor belt. For these characteristics of the conveyor belt, the magnitude of the friction coefficient acting between the belt and the drum surfaces can be determined.

Dolomite and organic compost application for preventing acid mine drainage formation in a mesocosm system

Acid mine drainage (AMD) is one of most serious environmental problems facing mining industries. It results from oxidation of sulfide minerals contained in mining wastes, such as rock disposals in mine sites. This study was to investigate AMD formation from waste rocks containing potentially-acid forming (PAF) materials treated with dolomite and compost in a mesocosm system. The system comprised a plastic drum of 150-cm height and 50-cm diameter filled with 15-cm sand at the botom layer, over-laid by 50-cm mixture of PAF+10% of either dolomite or compost, and 35-cm top-soil layer on the top. The drum surface of the sand layer was equipped with a valve to drain leached water into a collecting container. The control was a similar constructed mesocosm without addition of either ameliorant. The drums were installed into the ground of the mined land so that their surfaces were as high as the surrounding soil surface and left under field condition. The leachate samples were taken two-weekly in the early two months and monthly until the day 487. The system demonstrated that both dolomite and compost significantly increased pH from around 3 to pH>6 and reduced dissolved Al and Fe concentrations. However, the dissolved Mn concentration was still high (>20 mg L−1) in all treatments even at the pH reached >6. .

Адаптация математической модели процесса кондуктивного замораживания к икре сазана как источнику лецитина и ее решение

In modern conditions the food industry of the Russian Federation needs high quality natural emulsifiers, for example, lecithins. It should be noted that the carp caviar, in particular, the sazan caviar contains a large amount of lecithin. Analysis of the positive and negative aspects of different approaches to the freezing process and its structural design leads to the conclusion that it is reasonable to use (both from the point of view of technology, power consuming and economy) a conductive energy removal from the product that is in contact with the working surface of the cooling unit made in the form of a drum with a refrigerant supplied inside it. Given that it is difficult to empirically determine the temperature over the volume of the frozen object, it is advisable to simulate the processes of internal transfer of thermal energy and its exchange at the interfaces between the sample and the external environment, as well as the cooling surface of the drum. The aim of the study was a mathematical model solution about internal heat transfer during sazan caviar freezing under heterogeneous boundary conditions. The object of the study is a thin layer of the sazan caviar. Putting into practice the mathematical model of heat transfer, which describes freezing a 5 mm thick caviar product by the contact method by means of the finite difference method was realized by using the Mathcad Professional software product. In the process of solving the mathematical model of freezing, it was revealed that at the end of the freezing procedure, the average volumetric temperature of the caviar reaches its rational value of –7.5°C, after which the caviar product can be transported to the storage places. Rational operating parameters 
 of the caviar product freezing process are: ambient air temperature up to 20°C; initial product temperature –10 ± 1°C; drum surface temperature up to –18°C; thickness of the frozen layer – 5 ± 0.5 mm; freezing time = 10 minutes.

Determining forces arising during the passage of cotton fiber between the fixed knife and working drum of the roller gin

The object of this study is a roller gin. Roller gins are installed in the gin shops of cotton factories and their purpose is to mechanically separate cotton fiber from seeds in fine-fiber varieties of cotton. The criteria for the technological evaluation of roller gin are the sum of defects and fiber contamination after ginning, the cleansing effect of gin on weeds, damage to seeds, and fiber tow effects. Existing methods do not fully reveal all the reserves of increasing the productivity of the machine, improving the design of the main working bodies of the roller gin, ensuring the effective operation of the machine, and preserving the natural qualities of fiber and seeds. The determination of the force on the surface of the drum during the ginning process is of great practical interest for designing main working bodies of roller gins. The efficiency and quality of the processed product depend on the interaction of the working drum and knife with the breaking organ in the process of fiber separation. The design of the drum and knife, their kinematic parameters, the stability of technological wiring largely determine both the performance of the gin and the quality of the fiber and seeds. Theoretical studies have been conducted to determine the factors that affect the performance of roller gin. Based on the results obtained, it is recommended to change the most important structural parameters of the machine. The obtained analytical expressions for the specific pressure and specific friction forces applied from the side of the drum surface to the processed mass of raw materials make it possible to conclude that when the load from the breaking body increases during the lower rebound, the process of grasping, dragging, and holding the fibers between the working drum and the fixed knife worsens

Theoretical analysis of the movement trajectory of a cotton piece thrown from the pile surface

The article contains information about the theoretical analysis of the trajectory of the cotton piece thrown from the surface of the piled drum in the 1XK aggregates available in cotton ginning enterprises. For this, in the recommended cleaning equipment, cotton pieces are dragged through the mesh surface by hanging the drum piles, and the separated impurities fall through the holes of the mesh surface. The piles eject the cotton piece at the appropriate speed. A piece of cotton moves in different trajectories depending on the value of the initial exit velocity and its mass. In this case, it is necessary to determine the impact zone of pile drums located in a row in the zone of cleaning cotton from small impurities. The results of theoretical studies on determining the mathematical model of the movement of cotton pieces along a drum with piles are presented. The problem of determining the impact zone of the next pile drum depending on the movement trajectory after the cotton piece is thrown from the surface of the pile drum in the process of cleaning cotton from small impurities has been solved. The value of the distance between the axis of pile drums was based on the analysis of the obtained trajectories of the movement of cotton particles and the constructed graphical relationships. In addition, the movement of cotton particles along the surface of the piles was analyzed. The results were obtained by analyzing the movement of a piece of cotton under the influence of external forces in order to ensure the transmission of small impurities separated from the mesh surface of the 1XK equipment, which is currently used in production, and the impact of the pile drum on the cotton flow.

Щодо надійності технологічного процесу подрібнення пожнивних решток

The article is devoted to finding ways to solve the problem of increasing the reliability of the technological process of shredding crop residues using shredding rollers with operating parts in the form of knife drums. The research presents a review and analysis of existing types of machines for shredding crop residues equipped with driven and non-driven active operating parts with their advantages and disadvantages. The ways and methods that should be considered when solving problems of improving the quality of grinding and reliability of this technological process are formulated. The article presents the content and methods of conducting experimental field studies of the process of shredding crop residues by a drum with knives installed on its surface at a certain angle of deflection between adjacent rows and with a shift of the line of row blades relative to the axis of the drum itself. It is proved that at certain values of these parameters, it is possible to achieve a significant increase in the reliability of the technological process, to virtually eliminate the negative phenomenon of clogging of the inter-row space with particles of plant stems and soil. The rational values of the angles of the knives on the surface of the chopping drum, substantiated in this work, allow increasing the intensity of chopping crop residues as a result of reducing the distance between the rows of knives. Thus, the approximate length of the particles of chopped plant stems can be reduced from 21.4 cm to 17.4 cm, without negative consequences for the reliability of the technological process.

Analysis of the main design and operating parameters of the device for the fermentation of bird droppings

The study on the utilization of poultry droppings put forward the need for the constructive and technological improvement of the biofermentation device. A drum-type bioreactor better meets the requirements for the technological process of eco-friendly biologically active fertilizer production from livestock and poultry wastes. However, the great size of the heat transfer surface of the bioreactor drum and its significant ejection momentum during spinning require quite a lot of energy. To decrease this consumption, the main constructive parameters should be optimized. The main reason is the sharp increase in prices for mineral fertilizers, the weak economic condition of most farms, the lack of advanced processing technologies and the use of organic fertilizers.
 Our aim in these studies was to analyze the types of design and operating parameters of the device for the fermentation of bird droppings. To this end, we conducted a study on the disposal of bird droppings, and also put forward the need for constructive and technological improvement of the biofermentation device. One of such ways to solve the problem was a drum-type bioreactor, which, according to our research indicators, better meets the requirements for the technological process of producing environmentally friendly biologically active fertilizers from animal husbandry and poultry waste, however, the size of this equipment of the heat transfer surface of the bioreactor drum and its significant emission pulse during rotation require a rather large waste of energy. To reduce this consumption, it is necessary to optimize the basic design parameters.
 Devices that work continuously were recognized as the most promising. They fully meet the technological and operational requirements

A simple mechanical model of the drumroll

We propose an experiment in which the sound of a drumroll is recorded and analysed according to a simple mechanical model in which the inelastic restitution coefficient of the collision between the stick and drum surface, as well as the ongoing kinematics of the drumstick, are considered. The agreement shows that this model is well suited for describing the most relevant features of drumstick behaviour during this type of motion.

Hydrogen Sulfide Measurement of Degraded Corrosion Inhibitor with Glass Tube Detector in Oil & Gas Industry

Introduction: Corrosion inhibitor (CI) is injected as carbon steel pipe corrosion protection with sulfur-containing substances in the product. One type of them is thioglycolic acid (TGA). Besides having benefits in maintaining pipe integrity, TGA can be decomposed to HS (hydrogen sulfide) due to changes in ambient temperature during storage, such as direct sunlight exposure on the field. This irritant gas can pose a risk to the health of chemical workers. Therefore, this study aims to measure the concentration of H2S in a CI product containing TGA. Method: The data were collected from an oil and gas company measurement report on 12 CI drums with 1-3%w of TGA content by using a glass tube detector. Measurements were performed by varying the measurement distance (0 and 10 cm from the mouth of the drum), observing the condition of the inflated drum surface, and determining the existence of internal pressure. Results: All samples were contained H2S, and the inflated drums had higher H2S content than those that were not inflated up to more than 200 ppm in the drum bore. At this concentration, workers can experience pulmonary edema significantly prolonged exposure. Biological monitoring can be done by analyzing thiosulfate content in urine and blood after exposure or routine examination at the end of the work shift. Conclusion: CI with TGA content has the potential of high H2S concentration, and it requires risk control such as engineering control, administration control, and PPE application to minimize the health impact of H2S exposure to the workers.

Friction-induced noise in drum brakes: finite-element modeling and experiments with special focus on damping

Brake squeal in friction brakes is a typical audible noise phenomenon in vehicles leading to high development and sometimes warranty costs for the suppliers. The friction forces generated during braking are responsible for self-excited vibrations in the audible frequency range starting from 1hbox { kHz}. In the past countermeasures against friction-induced vibrations are mostly investigated for disk brakes while the present study focuses on drum brakes. Damping is in the context of self-excited vibrations often one of the key measures. Nowadays recuperative braking in electric vehicles relieves the conventional friction brake. Due to safety reasons, electric vehicles need to possess at least a second independent brake system. Therefore, simpler drum brakes are on the rise again when developing brake systems. Compared to brake disks, where damping elements can hardly be implemented, the freely accessible drum surface and the brake shoes offer so far unused potential for applying passive damping measures. The present paper focuses on how damping measures influence the noise behavior of drum brakes. Industrial and non-industrial brake components are investigated in detail. Experimental as well as numerical procedures are used to assess damping and noise characteristics.

Development of Chicken (Gallus gallus domesticus) Defeathering Machine

Because of the increased demand of chicken meat, the non-vegetarians worldwide has imposed big responsibility on poultry chicken processing industry. The chicken defeathering machines were made with different capacities but they still need of improvement. This paper is focused on the fabrication of a drum type small scale chicken defeathering machine. The drum type chicken defeathering machine was made using locally available materials. Design calculations were done to ensure appropriate shaft diameter supporting the rotating plate as this could affect the efficiency of the machine. The drum of the machine was made detachable and inside of it was the riveted ring on drum surface located above rotating plate. In addition to this, the machine was designed with chute that is made of two layers to separate the removal of feathers and waste water. Handle and wheel caster were included for ease handling and transport from one place to another place. The machine was tested using 28 days old broiler chicken.
 The machine was designed based on the identified problems on existing machine available from three local Dressing Plants namely Poultry Processing Plant in Municipality of Talavera, Nueva Ecija, Poultry Processing Plant in Barangay St. Nino, San Jose, Nueva Ecija and Poultry Processing Plant in Barangay Canitoan, Cagayan de Oro City. The identified problems of these existing machines were a) 10 percent of the chicken feathers was not removed, b) in a batch of 15 chicken, 2 pcs had broken legs; c) during the defeathering operation, workers have to pour manually 2 buckets (20-li capacity) of water, 3 d) unloading consumes about 60 seconds, and e) removing the feathers from the machine after operation was quite difficult.
 The overall dimension of chicken defeathering machine after fabrication is 1250 mm x 1160 mm x 650 mm and with a weight of 95 kg. The machine was designed to a capacity of 800 heads per hour. The performance evaluation of the machine has defeathering efficiency of 99.01% and defeathering efficacy of 95.85% at angular speed of 348 rpm. Thus, in this study, a small chicken defeathering machine was developed by improving its performance based on the problems identified above so as to make it more useful and adaptable by small scale poultry processors and poultry farmers who wish to have an added income from a dressed chicken over a live chicken.

Tracking transients in steelpan strikes using surveillance technology.

This paper presents advancements in tracking features in high-speed videos of Caribbean steelpans illuminated by electronic speckle pattern interferometry, made possible by incorporating robust computer vision libraries for object detection and image segmentation, and cleaning of the training dataset. Besides increasing the accuracy of fringe counts by 10% or more compared to previous work, this paper introduces a segmentation-regression map for the entire drum surface yielding interference fringe counts comparable to those obtained via object detection. Once trained, this model can count fringes for musical instruments not part of the training set, including those with non-elliptical antinode shapes.

Physical and mathematical modeling of the moving the raw cotton between directing wall and area ginning seeds

In article are brought algorithm and results brought numerically-experimental studies on qualitative and quantitative estimation of the law of the moving the raw cotton from directing walls outgoing between spiked-drum and netlike surface feeder aside worker of the camera ginning machines. It is known that the uniform supply of raw cotton to the ginning process has a direct impact on the efficiency of the ginning process. In the process of ginning, the cotton is cleaned on the surface of the pile drum and net of the supplier, and the crushed gin comes to the working chamber through the gin. As a result of the rotation of the saw cylinder in the working chamber, the cotton fiber is suspended and the rotation is started. As a result of the circular motion of the raw cotton, a raw material roller is formed. In this process, the actual problem is to ensure that the raw cotton consists of small pieces and is uniform in time and width of the equipment. The Comparison got given on calculation shows that increase the corner will bring about increase the growing forming displacement. Increase of this corner will bring the leaflet of the raw cotton about increase of length free moving.

A machine learning approach in drying of microalga Chlorella minutissima in a single rotary drum dryer for biodiesel production

Drying of Chlorella minutissima slurry was carried out in a single rotary drum dryer at varied drum surface temperature and rotational speed to achieve higher lipid yield for biodiesel conversion. Residual moisture content and lipid yield of the corresponding drum speed and drum surface temperature were mapped. Application of the machine learning tool classified the range of residual moisture content to be <10% (wet biomass) for high lipid recovery with an accuracy of 97%. Based on the drying time, lipid recovery, and energy consumption, drying at 80°C drum surface temperature with 0.3 rpm resulted ˃90% lipid recovery as compared to the bone-dried biomass. The energy consumption of 7.328 kWh for 1 kg of dried biomass was recorded with profound reduction in drying time as compared to oven and tray drying of algal slurry. The fatty acid methyl ester profile of C. minutissima biodiesel constituted higher proportion of saturated fatty acids followed by monounsaturated fatty acid and polyunsaturated fatty acids. Various fuel characteristics, namely, viscosity, density, free glycerin, triglycerides, diglycerides, monoglycerides, copper strip corrosion, flash point, cetane index, iodine value, calorific value, acid value, saponification value, phosphorous, sulfur, water, and ash contents were analyzed, and showed values within the specified limits of national and international biodiesel standards. Thus, considering the drying time, energy consumption, and lipid recovery with suitable fuel properties, the drum dryer could be recommended for drying the microalgal slurry for large-scale operation.