Enhancing the ride comfort of the off-road vibratory roller cab by adding damper hydraulic mount

In order to improve the vibratory roller’s ride comfort, a 3-D nonlinear dynamic model of the vehicle interacting with the off-road terrain is established. A damper hydraulic mount is studied and combined with the cab’s rubber mounts to simulate and evaluate the performance of the ride comfort. The weighted RMS acceleration responses of the vertical driver’s seat, the cab’s pitch and roll angle are chosen as objective functions. The results show that the cab’s rubber mounts combined with the damper hydraulic mount are clearly improved the ride comfort under various operating conditions. Especially, with damping coefficients cc3,4= 1.8 kN.s.m-1, the weighted RMS values of the vertical driver’s seat, the cab’s pitch and roll angle are greatly reduced by 27.8 %, 22.7 % and 64.3 % in condition of the vehicle traveling, and by 23.8 %, 20.0 % and 63.7 % in condition of the vehicle compacting on an elastic-plastic terrain

Evaluating the effect of the working conditions on the ride comfort and road friendliness of the heavy truck

This study proposes a nonlinear dynamic model of the heavy trucks to evaluate the influence of the various working conditions on the ride comfort and road friendliness of the heavy vehicles based on Matlab/Simulink software. The weighted root mean square (RMS) acceleration responses of the vertical driver’s seat, the cab’s pitch and roll angles, and the dynamic load coefficient (DLC) are chosen as objective functions. The influence of the vehicle velocity and loads on the different road surfaces are evaluated based on the standard ISO 2631-1. The results show that the vehicle’s ride comfort is clearly affected on the road surfaces of ISO level C and D at the range of the vehicle velocity. Especially, the vehicle’s ride comfort is very poor at the velocity of 10-30 m.s-1 on ISO level D. The road friendliness of the vehicle is greatly decreased in the condition of the half-loaded vehicle. Particularly the vertical dynamic wheel loads at 2nd axle strongly affect the road damage at the velocity of 10-30 m.s-1

Cost optimization of two-stage helical gearboxes with second stage double gear-sets

In practice, the cost of a gearbox plays a very important role in the trade. Therefore, reducing the cost of gearboxes is an important task not only when manufacturing the gearboxes but also when designing them. In order to reduce the cost of a gearbox, there are many solutions in which determining the optimal partial gear ratios of a gearbox is an effective measure. This is because it not only the size, the mass but also the cost of a gearbox depends greatly on the partial gear ratios. This work presents a method for calculating the cost function of two-stage helical gearboxes with second-stage double gear-sets based on the mass of the components that construct the gearbox. The cost objective function is minimized to achieve the optimal transmission ratios. Furthermore, screening experiments are carried out with nine important input parameters that have significant effects on the optimum transmission ratio of the second stage. These parameters are the total gearbox ratio, the coefficient of wheel face width of the first stage, coefficient of wheel face width of the second stage, the allowable contact stress of the first stage, the allowable contact stress of the second stage, the output torque, the cost of gearbox housing, the cost of gears, and the shaft cost. The experimental results of were analysed by using the Analysis of Variance (ANOVA) method with the help of Minitab 19 software. The results demonstrate that the effective weight of the input parameters and their interactions on the output response was investigated. Also, a regression model for computing the optimal transmission ratio of the second stage was proposed. This brings significance not only in the design process but also in manufacturing since the gearbox cost can decreas

A Study Of UV-curable Offset Ink Emulsified With An Alternative Isopropyl Alcohol-free Fountain Solution

In the present research, fountain solution without isopropyl alcohol (IPA) for Ultraviolet offset curing ink (UV ink) was prepared by using Ethylene Glycol Mono-butyl Ether (EGME) as a substitute for IPA. The effect of EGME concentration on the water pick-up characteristics, tack value, rheological behaviors, and curing time of UV offset inks was investigated. Water pick-up characteristics, tack value and rheological behaviors were measured by Duke Ink water emulsification tester, Tack-o-scope and cone-plate rheometer, respectively. The curing time of the UV ink was evaluated by the rub test of printed sheet samples proofed on the polymer film at the standard solid ink density and the same ink thickness. The results revealed that an increase in EGME concentration increased the water pick-up characteristics of the UV ink. There was no significant influence of EGME on the tack value of UV inks. However, the tack value of UV ink was significantly affected by fountain concentration in UV inks and UV ink color. The addition of EGME reduced the dynamic viscosity and thixotropic property of UV inks but did not change the flow behavior of UV ink as shear thinning. This study indicates that UV ink emulsified with a higher EGME concentration fountain solution needs a longer curing time. The cyan UV ink has the longest curing time. Finally, the fountain solution of 10% EGME exhibited good performance in water pick-up characteristics, tack value, rheological behaviors, and curing time of UV inks

Network Coding with Multimedia Transmission and Cognitive Networking: An Implementation based on Software-Defined Radio

Network coding (NC) is considered a breakthrough to improve throughput, robustness, and security of wireless networks. Although the theoretical aspects of NC have been extensively investigated, there have been only few experiments with pure NC schematics. This paper presents an implementation of NC under a two-way relay model and extends it to two non-straightforward scenarios: (i) multimedia transmission with layered coding and multiple-description coding, and (ii) cognitive radio with Vandermonde frequency division multiplexing (VFDM). The implementation is in real time and based on software-defined radio (SDR). The experimental results show that, by combining NC and source coding, we can control the quality of the received multimedia content in an on-demand manner. Whereas in the VFDM-based cognitive radio, the quality of the received content in the primary receiver is low (due to imperfect channel estimation) yet retrievable. Our implementation results serve as a proof for the practicability of network coding in relevant applications

Design and fabrication of the trapezoidal electrostatic comb-drive actuator

This paper reports the design, fabrication and characterization process of the trapezoidal Electrostatic Comb-drive Actuator (ECA) with the slope angle α=20. Together with the trapezoidal ones, the rectangular ECA with identical dimension was also designed and fabricated for comparison purpose. In order to reduce calculating deviation, the fringing effect was also taken into consider while carrying out theoretical analysis. The obtained results pointed out the fact, that the trapezoidal ECA excels the rectangular ones with the same numbers of teeth in electrostatic force and displacement generation, while requires relatively low driving voltage. But it is also observed that with higher driving voltage (larger than 50V), the trapezoidal ECA starts to lose its stability (the lateral pull-in phenomenon occurs)

Joint optimization of monitoring quality and replacement decisions in condition-based maintenance

The quality of condition monitoring is an important factor affecting the effectiveness of a condition-based maintenance program. It depends closely on implemented inspection and instrument technologies, and eventually on investment costs, i.e., a more accurate condition monitoring information requires a more sophisticated inspection, hence a higher cost. While numerous works in the literature have considered problems related to condition monitoring quality, (e.g., imperfect inspection models, detection and localization techniques, etc.) few of them focus on adjusting condition monitoring quality for condition-based maintenance optimization. In this paper, we investigate how such an adjustment can help to reduce the total cost of a condition-based maintenance program. The condition monitoring quality is characterized by the observation noises on the system degradation level returned by an inspection. A dynamic condition-based maintenance and inspection policy adapted to such a observation information is proposed and formulated based on Partially Observable Markov Decision Processes. The use and advantages of the proposed joint inspection and maintenance model are numerically discussed and compared to several inspection-maintenance policies through numerical examples

Network Coding with Multimedia Transmission and Cognitive Networking: An Implementation based on Software-Defined Radio

Network coding (NC) is considered a breakthrough to improve throughput, robustness, and security of wireless networks. Although the theoretical aspects of NC have been extensively investigated, there have been only few experiments with pure NC schematics. This paper presents an implementation of NC under a two-way relay model and extends it to two\ua0non-straightforward scenarios: (i) multimedia transmission with layered coding and multiple-description coding, and (ii) cognitive radio with Vandermonde frequency division multiplexing (VFDM). The implementation is in real time and based on software-defined radio (SDR). The experimental results show that, by combining NC and source coding, we can control the quality of the received multimedia content in an on-demand manner. Whereas in the VFDM-based cognitive radio, the quality of the received content in the primary receiver is low (due to imperfect channel estimation) yet retrievable. Our implementation results serve as a proof for the practicability of network coding in relevant applications

Bisbenzylisoquinoline alkaloids from Mahonia nepalensis

From the wood of Mahonia nepalensis DC. 1821, two bisbenzylisoquinolines homoaromoline (1) and isotetrandrine (2) were isolated by using various chromatoghraphies. Their structures were characterized on the basis of the spectroscopic data (1D-NMR, HSQC, HMBC, ESI-MS) in comparison with the literature. This is the first report of 1 - 2 from Mahonia nepalensis. Keywords: Mahonia nepalensis, Isotetrandrine, Homoaromoline, Bisbenzylisoquinoline

VẬT LIỆU TIO2/THAN HOẠT TÍNH TỪ TRO TRẤU VÀ KHẢ NĂNG HẤP PHỤ XANH METHYLENE

In the present work, TiO2/activated-carbon composite (TiO2/RHAC) was synthesized with an assembly method. Activated carbon was fabircated from rice husks. The water-soluble titanium complex was synthesized from anatase via the peroxide complex. The mixture of activated carbon and water-soluble TiO2 was calcined at 600 °C. The obtained samples were characterized by using XRD, SEM, EDX, and UV-Vis-DR. The results show that the obtained composites exhibit excellent adsorption toward methylene blue (MB). The equilibrium data fit the Langmuir isotherm model well. The maximum monolayer capacity calculated from the Langmuir model is 144.7 mg·g–1. The TiO2/RHAC could be self-cleaned after use by photocatalytic degradation. The adsorption capacity insignificantly decreases after three recycles of adsorption, and TiO2/RHAC is a promising adsorbent for removing dyes from the aqueous environment.Trong nghiên cứu này, TiO2/than hoạt tính từ tro trấu (TiO2/RHAC) đã được tổng hợp bằng phương pháp trộn lẫn than hoạt tính và phức titanium. Than hoạt tính được tổng hợp từ tro trấu và phức titanium hòa tan trong nước tổng hợp từ anatase bằng cách tạo phức peroxide. Hỗn hợp được nung trong môi trường thiếu oxy ở 600 °C. Vật liệu tổng hợp được phân tích bằng nhiễu xạ tia X, kính hiển vi điện tử quét và đẳng nhiệt hấp phụ/giải hấp phụ ni tơ. TiO2/RHAC có khả năng hấp phụ cao đối với xanh methylene. Số liệu đẳng nhiệt cân bằng tuân theo mô hình Langmuir và dung lượng hấp phụ cực đại tính theo mô hình này là 144,7 mg·g–1. Chất bị hấp phụ có thể được loại bỏ bằng cách chiếu sáng bằng đèn chiếu nhờ khả năng xúc tác quang hóa của nó. Sau ba lần tái sinh, dung lượng hấp phụ thay đổi không đáng kể. TiO2/RHAC có tiềm năng làm chất hấp phụ xử lý phẩm màu nói chung