Validation of a coupled multibody and TEHL simulation by a piston/cylinder component test rig

A tribological highly stressed contact in the actuating system of axial piston machines is located between the control piston and the control chamber. This paper presents a new type of component test rig for measuring the frictional force and the gap heights between piston and cylinder. For this purpose, the original system is reduced to the actuator system, whereby the real kinematics and the loading forces are maintained. The axial movement of the control piston and the pressure in the control chamber can be configured individually. The measurement results of different parameter variations are compared with the results of the simulation. The simulation based on a coupled multibody and TEHL simulation with a transient, three-dimensional, thermal elastohydrodynamic contact calculation.

Real-time temperature calculation and temperature prediction of wet multi-plate clutches

Many applications of wet multi-plate clutches are within safety-critical areas since malfunction or failure of the clutch is often equivalent to “loss of drive”.The main criterion for the estimation of damage and endurance of wet multi-plate clutches is the temperature on the friction interface. Owing to the thin, rotating geometry of the plates, determination of relevant temperatures in operation mode is almost impossible. State of the art is that there is no general applicable model for real-time estimation of clutch temperatures during operation.This contribution presents a validated parametric real-time temperature model that is applicable to various use cases and operating conditions. The model enables the calculation of the actual clutch temperature during operation and the prediction of temperature for future shifting operations.The model is validated by comparing temperature measurements from a component test rig and from the KUPSIM thermal clutch design tool with the developed real-time temperature calculation. The validity of the model for serial parts from industry and automotive applications under various load cases (clutch mode, continuous slip, non-steady slip) is demonstrated. The deviation between measurement and calculation are typically very small (< 5 K). The temperature prediction allows a highly accurate (deviations typically < 5 K) conservative prediction of the thermal load for future shifting operations.The model can thus contribute to the increase of operational safety of wet multi-plate clutches while at the same time facilitating optimal component design by reducing thermal over-dimensioning of clutches.

Antimicrobial Properties of Acrylic Resin Incorporated with Propolis Nanoparticles

Objectives: One of the main problems with polymethyl methacrylate (PMMA) used for the fabrication of oral removable appliances is plaque accumulation due to surface porosities. Incorporation of antimicrobial agents in this material might help tackle this problem. The aim of this study was to evaluate the antimicrobial activity of PMMA acrylic resin incorporated with propolis nanoparticles (PNPs). Materials and Methods: Antimicrobial properties of acrylic resin incorporated with PNPs were assessed against Streptococcus mutans (S. mutans), Streptococcus sanguinis (S. sanguinis), Lactobacillus acidophilus (L. acidophilus) and Candida albicans (C. albicans). Acrylic discs were fabricated in four groups: A control group without PNPs and three experimental groups containing 0.5%, 1% and 2% concentrations of PNPs. Disc agar diffusion (DAD) test was performed to determine the antimicrobial effects of PNPs by measuring the microbial growth inhibition zones on Muller-Hinton agar plates. The eluted components test evaluated the viable counts of microorganisms in liquid medium after 24 and 72h. Finally, biofilm inhibition test assessed the efficacy of PNPs for inhibition of biofilm formation. P<0.05 was considered significant. Results: The acrylic discs failed to produce microbial inhibition zones in the DAD test. Discs containing 1% and 2% nanoparticles showed anti-biofilm effects on all four microbial species. The colony counts of all microorganisms significantly decreased following exposure to liquids containing nanoparticles after 24 and 72h in eluted component test. Conclusion: PMMA acrylic discs incorporated with PNPs presented some antimicrobial properties against S. mutans, S. sanguinis, L. acidophilus, and C. albicans.

Potential of Bagasse as Raw Material for Lignosulfonate Surfactant

Anionic surfactants are generally used in surfactant injections because they are good, resistant in storage and stable. Furthermore, Commercially, anions are produced in the form of carboxylates, sulfates, sulfonates, phosphates, or phosphonates. The surfactants used in the process of implementing Enhanced Oil Recovery (EOR) are generally petroleum-based, such as Petroleum Sulfonate. Therefore, an increase in oil price, leads to an increase in the price of surfactant and the operational costs becomes relatively expensive. Lignosulfonate is a type of anionic surfactant which is made with lignin as raw material. This lignin is found in many plants, including wood stalks, plant leaves, peanut shells, corn cobs, bagasse, empty bunches of oil palm and wheat straw. Based on the results of previous studies, 25% of lignin component was discovered in bagasse. This may be a consideration that there is enough lignin in bagasse to be used as raw material in the production of lignosulfonate vegetable surfactants. Furthermore, lignin from bagasse is used because bagasse is easy to obtain, cheap and an environmental friendly vegetable waste. Currently, bagasse is only used as fuel in steam boilers and papermaking, cement and brick reinforcement, a source of animal feed, bioethanol, activated charcoal as adsorbent and compost fertilizer. This is a consideration to optimize the use of bagasse to become lignosulfonate as an alternative for surfactants in the petroleum sector. The purpose of this study is to show that lignin from bagasse has the potential of becoming a lignosulfonate surfactant. There are several studies that have processed bagasse into sodium lignosulfonate. The component test on the results showed that the surfactant component of sodium lignosulfonate from bagasse was almost the same as the commercial standard lignosulfonate component. Furthermore, the results of the HLB (Hydrophilic–Lipophilic Balance) value test show that the sodium lignosulfonate surfactant from bagasse can function as an emulsion form which is a required parameter for the surfactant injection mechanism. Based on the discussion of the study results, bagasse has the potential as a raw material to be processed into lignosulfonates.

Reliability Assessment Based on Multisource Information Fusion Method for High Pressure Natural Gas Compressors

Compressor units used for long-distance transportation natural gas pipeline pressurization have high-pressure and high-risk characteristics. Hence, the scientific reliability assessment is important for high-pressure compressor units, to evaluate the reliability standard, find the performance deficiency, and provide references for operation and maintenance. The classical reliability assessment method is not suitable for the complex and high-reliability equipment, like high-pressure compressor units and pipelines. The reliability assessment of the high-reliability equipment is faced with the challenge of the multisource information. A reliability assessment method based on the multisource information fusion is proposed in this work. The fusion resources consist of design information, component test information, and trial operation information. The reliability of high-pressure compressor units can be assessed by fusing the characteristic parameters, from component-based assessment, function-based assessment, quality evaluation, and life model, by D–S evidence theory. A case study is conducted to verify the proposed reliability assessment method in a 20 MW-class high-pressure compressor. There are four information resources in the case, i.e., component test data, design information, operation data, and simulation data. The compressor reliability is assessed as 99.32%, validated by the statistical assessment result based on long-term shutdown reports. This application points out the existing weakness in the high-pressure compressor units and indicates the directions for improving the design, analysis, operation, and failure prevention technologies. It reveals that the reliability assessment based on multisource information can provide a guarantee for the operation and maintenance of high-pressure compressor units. Meanwhile, the proposed method has good expansibility, which may be used in more fields.

Dampak Kapasitas Aerobik dan Elevation Training Mask (ETM) Menggunakan Metode High Intensity Interval Training (HIIT) Terhadap Kemampuan Fisiologik pada Pemain Futsal Putri

This study was aimed at investigating the effect of using an Elevation Training Mask (ETM) with the High Intensity Interval Training (HIIT) Training Method on physiological abilities based on aerobic capacity. This research was an experimental study with a 2x2 factorial design. This study used aerobic and anaerobic physical component test instruments. This study involved 20 female futsal players as participants. Data analysis used statistical calculations with the help of the SPSS application. The results of the study showed that there was no increase in the physiological abilities of female futsal players based on the use of ETM. It indicated that there was an increase in the physiological ability of female futsal players based on aerobic abilities and there was no interaction between the use of ETM and aerobic capacity in increasing the physiological abilities of female futsal players. This study also concluded that female futsal players with high aerobic capacity were more effective than female futsal players with low aerobic capacity using the HIIT training method, both with high aerobic capacity using ETM and not using ETM compared to low aerobic capacity using ETM or without ETM. Apart from that, there was no interaction found. The implication of the research result shows that, in physical training, the training method must be adjusted to the aerobic capacity of the player by paying more attention to the principles of the training and specificity. Besides that, it is necessary to carry out further research using ETM to see the effect in lung capacity, so that it would be more comprehensive.