Kinematics and Path Following Control of an Articulated Drum Roller

Automatic navigation of an articulated drum roller, which is an articulated steering type vehicle widely used in the construction industry, is highly expected for operation cost reduction and improvement of work effi- ciency. In order to achieve the path following control, considering that its steering system is articulated steering and two frames are articulated by an active revolute joint, a kinematic model and an error dynamic state-space equation of an articulated drum roller are proposed. Besides, a state- feedback control law based on Lyapunov stability theory is also designed, which can be proved to achieve the purpose of control by the analysis of stability. What＇s more, to evaluate the performance of the proposed method, simu- lation under the MATLAB/Simulink and experiments using positioning algorithm and errors correction at the uneven construction site are performed, with initial dis- placement error （-1.5 m）, heading error （-0.11 tad） and steering angle （-0.19 rad）. Finally, simulation and exper- imental results show that the errors and steering angle can decrease gradually, and converge to zero with time. Meanwhile, the control input is not saturated. An articu- lated drum roller can lock into a desired path with the proposed method in uneven fields.

Performance of rotating drum biofilter for volatile organic compound removal at high organic loading rates

Uneven distribution of volatile organic compounds （VOCs） and biomass, and excess biomass accumulation in some biofilters hinder the application of biofiltration technology. An innovative multilayer rotating drum biofilter （RDB） was developed to correct these problems. The RDB was operated at an empty bed contact time （EBCT） of 30 s and a rotational rate of 1.0 r/min. Diethyl ether was chosen as the model VOC. Performance of the RDB was evaluated at organic loading rates of 32,1, 64.2, 128, and 256 g ether/（m^3·h） （16.06 g ether/（m^3·h） ≈ 1.0 kg chemical oxygen demand （COD）/（m^3·d））. The EBCT and organic loading rates were recorded on the basis of the medium volume. Results show that the ether removal efficiency decreased with an increased VOC loading rate. Ether removal efficiencies exceeding 99% were achieved without biomass control even at a high VOC loading rate of 128 g ether/（m^3·h）. However, when the VOC loading rate was increased to 256 g ether/（m^3·h）, the average removal efficiency dropped to 43%. Nutrient limitation possibly contributed to the drop in ether removal efficiency. High biomass accumulation rate was also observed in the medium at the two higher ether loading rates, and removal of the excess biomass in the media was necessary to maintain stable performance. This work showed that the RDB is effective in the removal of diethyl ether from waste gas streams even at high organic loading rates. The results might help establish criteria for designing and operating RDBs.

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 cracking. There were some studies on coke drums in the form of bulging and 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 devel- oped 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.

The Mathematical Simulation of Brush Drums in a Dual Saw Cylinder Chamber Gin for the Purpose of Increasing the Quantity of Captured Cotton Fiber from Saw

An analysis of the efficiency of the ginning of cotton fibers with two saw cylinders has been carried out. In comparison to a one-cylinder machine, the 2 cylinder approach can help to preserve the natural characteristics of cotton fiber and seeds. This technology allows economizing electricity and decreasing damage to fiber and also increases the productivity of the machine.

DESIGN AND APPLICATION OF MODEL DZI LOG GRAPPLE DRIVEN BY AN ELECTRIC DRUM

This article introduces the history and development of log grapple in China.Ac-cording to the special conditions of Chinese forest areas,we have selected log grapple driven byelectric drum,and have analyzed and calculated its parameters theoretically.This is the first loggrapple driven by an electric drum made successfully in China.The Model DZ1 log grapple has alarge closing force,works safely and is suitable for the special forest working conditions inChina.

LEAD ISOTOPE STUDIES ON ANCIENT BRONZE DRUMS OF GUANGXI CHINA

A study has been reported on 208Pb/206Pb and 207Pb/206Pb ratio variations in ancient drums and Cu-., Pb- ores from Guangxi, China and can indicate that the Cu- and Pb- bearing ores for making the Beiliu and the Lingshan type drums were taken from Tongshiling of Beiliu County and its vicinity, that were not only ancient sites for smelting the copper ores, but possibly also for casting the bronze drums. Some of the Lengshuichong type drums have abnormal Pb isotopic ratios, which means that they were made of special ore sources, one of the possibilities is that the ore material or the drums were transported from South- East Asia to Guangxi Province, because they have been excavated there too.

SOME MECHANISMS OF DRUM BRAKE OSCILLATION AND SQUEAL

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Analysis of transient temperature field in coke drums

One of the primary reasons leading to bulging and cracking in a coke drum is the severe temperature gradient due to cyclic temperature variation. Based on the twodimensional heat conduction theory, an analytical solution of the transient temperature field in the coke drum is obtained, which is different from the known FEM results. The length of the coke drum is considered finite. The dynamic boundary conditions caused by fluid uninterrupted rising in oiling and watering stages are simulated with the iteration method. Numerical results show that the present theoretical model can accurately describe basic features of the transient temperature field in the coke drum. Effects of the geometry of the coke drum and the rising velocity of quench water on the axial temperature gradient are also discussed.

A Simple Approach to Determine Noise Frequency of Boiler Drum Level

This paper proposed a simple approach to determine noise frequency of boiler drum level in order to improve control performance. Based on analysis of uncertainty of drum level, the redundant oscillation component of signal, noise is ascribed to the surface wave of drum water. According to the characteristic of surface wave, a new method was proposed to determine noise’s frequency band. By gradually removing the lowest frequency component of signal, the variance of remained component is calculated and observed. An apparent turning point was found and the corresponding critical frequcncy was determined. With this result a low-pass filter was designed to separate noise component. Finally validation is conducted by comparing the proposed method and conventional ones. Results show the accuracy and simpleness of the proposed method.

Effects of cooling rate on vermicular graphite percentage in a brake drum produced by onestep cored wire injection

In this research, a vermicular graphite cast iron brake drum was produced by cored wire injection in a one-step method. Silica sand and low-density alumina-silicate ceramic were used as molding materials in order to investigate the effect of cooling rate on percentage of vermicular graphite and mechanical properties of the brake drum casting. Several thermocouples were inserted into the casting in the desired positions to measure the temperature change. By means of one-step cored wire injection, the two residual concentrations of Mg and RE were effectively controlled in the ranges of 0.013%-0.017% and 0.019%-0.025%, respectively, which are crucial for the production of vermicular graphite cast iron and the formation of vermicular graphite. In addition, the cooling rate had a significant effect on the vermicular graphite percentage. In the case of the silica mold brake drum casting, there was an obvious difference in the cooling rate with the wall change, leading to a change in vermicular graphite percentage from 70.8% to 90%. In the low-density alumina-silicate ceramic mold casting, no obvious change in temperature was detected by the thermocouples and the percentage of the vermicular graphite was stable at 85%. Therefore, the vermicular graphite cast iron brake drum with a better combination of mechanical properties could be obtained.

Investigation of solids segregation of binary mixtures in a rotating drum at various Froude numbers

To investigate the effect of the Froude number(Fr)on solid segregation in a rotating drum,a two dimensional mathematical modelling on solids behaviour in horizontally oriented rotating drums operated in rolling,cascading and cataracting modes has been carried out by using Euler-Euler multi-fluid model in Fluent6.2 environment.Small particles and big particles are used in the work as binary mixtures to investigate segregation characteristics.The effect of Froude number(rotating velocity)on the flow field is investigated.It is found that the model captures the main features of solids motion and segregation in the drum and numerical results agree well with limited experimental data for solid velocity.

Particle breakage of sand subjected to friction and collision in drum tests

This paper presents a laboratory experimental study on particle breakage of sand subjected to friction and collision,by a number of drum tests on granular materials(silica sand No.3 and ceramic balls)to investigate the characteristics of particle breakage and its effect on the characteristics of grain size distribution of sand.Particle breakage increased in up convexity with increasing duration of drum tests,but increased linearly with increasing number of balls.Particle breakage showed an increase,followed by a decrease while increasing the amount of sand.There may be existence of a characteristic amount of sand causing a maximum particle breakage.Friction tests caused much less particle breakage than collision tests did.Friction and collision resulted in different mechanisms of particle breakage,mainly by abrasion for friction and by splitting for collision.The fines content increased with increasing relative breakage.Particle breakage in the friction tests(abrasion)resulted in a sharper increase but with a smaller total amount of fines content in comparison with that in the collision tests(splitting).For the collision tests,the fines content showed a decrease followed by an increase as the amount of sand increased,whereas it increased in up convexity with increasing number of balls.The characteristic grain sizes D_(10) and D_(30) decreased in down convexity with increasing relative breakage,which could be described by a natural exponential function.However,the characteristic grain sizes D50 and D60 decreased linearly while increasing the relative breakage.In addition,the coefficients of uniformity and curvature of sand showed an increase followed by a decrease while increasing the relative breakage.

Thermomechanical Behavior of Brake Drums Under Extreme Braking Conditions

Braking efficiency is characterized by reduced braking time and distance,and therefore passenger safety depends on the design of the braking system.During the braking of a vehicle,the braking system must dissipate the kinetic energy by transforming it into heat energy.A too high temperature can lead to an almost total loss of braking efficiency.An excessive rise in brake temperature can also cause surface cracks extending to the outside edge of the drum friction surface.Heat transfer and temperature gradient,not to forget the vehicle’s travel environment(high speed,heavy load,and steeply sloping road conditions),must thus be the essential criteria for any brake system design.The aim of the present investigation is to analyze the thermal behavior of different brake drum designs during the single emergency braking of a heavy-duty vehicle on a steeply sloping road.The calculation of the temperature field is performed in transient mode using a three-dimensional finite element model assuming a constant coefficient of friction.In this study,the influence of geometrical brake drum configurations on the thermal behavior of brake drums with two different materials in grey cast iron FG200 and aluminum alloy 356.0 reinforced with silicon carbide(SiC)particles is analyzed under extreme vehicle braking conditions.The numerical simulation results obtained using FE software ANSYS are qualitatively compared with the results already published in the literature.

Reduction of Environmental Impact of Drum Machine Washing

An improvement of efficiency of the horizontally rotating drum washing machine is possible by using a more open type of drum, essentially without suds in the annulus, by using a pump to wet the clothes during rotation and fall. Modelling and simulation are used to quantify these claims and further optimize the design of the horizontal washing machine. The flow of suds inside the deforming clothes at impact with the drum is calculated. The wash performance is shown to be largely proportional to the open perforation area in the drum. The traditional design uses 1/8 of drum area for the perforation holes. A significant reduction of water, detergent, electrical energy, and wash time, with parity in wash performance, provides a step towards a cleaner and more sustainable future.

Feed-Drum和SkinAct膜鸣扩增型乐器的音准调控

介绍了Feed-Drum和SkinAct膜鸣扩增型乐器的研发背景,并对其鼓膜振荡模式图和控制系统中的音准调控方式做出理论分析。

Influence of the Mode of Discrete Drum Speed and the Number of Inputs on the Technological Parameters of the Yarn Produced

This article is devoted to the research work aimed at improving the quality of yarns obtained by pneumomechanical spinning. The yarn quality indicators obtained at different speed modes of the pneumomechanical spinning machine discrete drum were studied and analyzed. The effect of the number of incisions of the sawtooth coatings on the discrete drum on the quality indicators of the yarn produced was also studied. The results of the experiments were analyzed by graphical and histogram methods, and alternative options were suggested.

The Effects of a Drums Alive Kids® Beats Intervention vis a vis Behavior on Children with Developmental Delays

The purpose of this study was to determine if the Drums Alive Kids Beats intervention could improve behavior in children with developmental delays (DD). The original pilot study that this study on behavior is linked to is titled, “The Effects of a Drums Alive Kids Beats Intervention on the Physical Performance and Motor Skills of Children with Developmental Delays,” which was published in the December edition of the Open Journal of Pediatrics (OJPED, Vol.11 No.4 2021). During the facilitation of said intervention on physical and motor skills, the facilitators noticed unanticipated improvements in behavior, both individually and as a community through better awareness, self-control, self-efficacy, social interaction, and positive energy. Therefore, while maintaining the integrity of the MOT 4 - 6 testing protocols and Drums Alive intervention, a parallel study was conducted to objectively measure six behavioral domains, namely, motivation, impulse control, coordination, concentration, implementation of tasks, and creativity using a self-designed measurement tool with three elements for each domain that was approved by Dr. Heiner Lagenkamp, Department of Sports and Physical Activities, Teaching and Research, Ruhr University, Germany. The 20 participants were German students between 5.10 and 10.2 years of age with no inclusion or exclusion characteristics who were divided into two intervention groups, IG Kindergarten (IG Kinder) and IG Elementary (IG Elem), with varied DD, i.e., transgressive behavior, ADHD, ADD, autism, anger management, visual acuity, self-control, and self-esteem. During the MOT 4 - 6 study and Drums Alive Kids Beats intervention, the facilitators monitored and assessed each participant for pre- and post-performance vis a vis behavior concurrently with physical and motoric skills. As the original study provided statistically significant improvements of between 14% - 24% in physical and motor skill performance with regards to overall scoring and 7 subdivisions of tasks, the results of this parallel study on behavior, with its 6 domains and 18 elements of between 24% - 28%, were even more compelling. The evidence indicated that the Drums Alive Kids Beats intervention with its multidisciplinary approach of music, movement, and drumming, could be used as an effective tool and therapeutic approach to improve behavior in children with developmental delays.

The Effects of a Drums Alive^®Kids Beats Intervention on the Physical Performance and Motor Skills of Children with Developmental Delays

The objective of this original pilot study was to determine if the Drums Alive® Kids Beats intervention could provide statistically significant improvements to physical and motor skill performance on participants with Developmental Delays (DD) using the Dusseldorf Motor-Proficiency-Test for children (MOT 4-6) model. The researchers selected the research-based Drums Alive Kids Beat intervention because of its multidisciplinary methodology that in previous studies demonstrated positive effects on physiological, psychological, neurological, educational, rhythmical, and socio-emotional literacy. Facilitators used standardized Drums Alive approved lesson plans and equipment to conduct the intervention through a battery of music, movement and drumming-centered exercises and activities. The 30 participants were German students between 4.9 and 10.2 years of age, without any inclusion or exclusion characteristics, who were divided into three groups consisting of two intervention groups: IG Kindergarten (IG Kinder), IG Elementary (IG Elem) with varied physical, social, and emotional DD that affected gross and fine motor skills, movement, coordination, and behavioral control;and, a Control Group (CG) that had normal physical and motor skill development (Table 1). The results of the study suggested that the Drums Alive Kids Beats intervention provided statistically significant improvements in physical and motor skill performance in children with DD, namely, 24% improvement (IG Kinder), 14% (IG Elem) vice a minor 4% improvement (CG). Of note, during this study to measure physical capability pre- and post-intervention, the facilitators noticed significant improvements in behavior in both IG groups;therefore, they chose to conduct a collateral study to measure six behavioral domains which will be documented in a future publication to demonstrate the exclusive relationship between the Drums Alive Kids Beats intervention and improvement in behavior.