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In recent years, the adoption of alternative fuels and hybrid vehicles has necessitated radical changes to meet the energy needs of the automotive sector. Hybrid electric vehicles are used as a perfect step between traditional fossil fueled internal combustion engines and fully electric vehicles. Deeply related to this, complicated industry and manufacturers need simulation programs to reduce both the cost of test sets and to use time with the highest efficiency. Before the production, especially in automotive sector, the simulation and prototyping procedure is playing an indispensable role. For this study, the AVL-Cruise simulation tool was chosen. Due to its capability to keep up with evolving technological structures, this program can be easily implemented in hybrid vehicle simulations. In this study, a hybrid engine model was created based on a 1.5 L, four-cylinder gasoline engine and a 10 kW electric motor. Energy analysis, based on the variations in the CVT and AMT transmissions of a hybrid motor, was conducted under three different driving cycles and compared in detail. Additionally, energetic balance like exergy is executed for this model. Sankey diagrams were employed to illustrate the differences and energy consumptions of the vehicle based on the selected modeling criteria. As a result, the CVT is slightly better behaviors than AMT both fuel consumption (2.5–4%), emission reducing (1.5–4.6%) and energetic balances (3.6–5%). • Hybrid vehicles energy analyses are determined with Sankey diagrams. • Effects of CVT and AMT transmission to HEVs energetic outputs were compared. • Effects of various driving cycles on HEV components were discussed detailed. • CVT is slightly better than AMT with reducing the fuel consumption and emissions. • For this study, CVT is more energetic efficiency with 5% improvement vs AMT. [ABSTRACT FROM AUTHOR]

Flood attacks on a network occur when attackers send a very high volume of traffic to a system. This leads to an exhaustion of resources of the targeted system. Such a system or infrastructure under attack won't be able to cope up with the services it needs to provide due to capacity overload. These types of attacks are also called as Denial of Service (DoS) attacks. As it is essential for companies and organizations to provide high speed and high-quality services the network in which it operates needs to be secured against DoS attacks. As it is said prevention is better than cure, it is always better to detect an attack in the preliminary stages itself and deny an attacker any opportunity to continue the assault on the system. There are various kinds of DoS attacks, in this study the focus is on three kinds of attacks and its detection ICMP flood attack, UDP flood attack and TCP SYN flood attack. The detection mechanism employed is based on packet symmetry which can be used in to monitor the data flow in a network and detect any malicious anomalies in the network traffic at any instant. The experimental results, show that the packet symmetry is a reliable metric to detect attacks on the network by checking the data flow in the ICMP, UDP and TCP layers. [ABSTRACT FROM AUTHOR]

• A tripod joint-CV joint transmission between parallel axis shafts can be homokinetic. • If connected to a CV joint, a tripod joint performs better than previously expected. • On cars, tripod joints can still be a good alternative to CV joints. • The transmission ratio of a tripod joint-CVJ driveshaft can now be exactly assessed. The paper presents a procedure to assess the instantaneous transmission ratio, in a generic configuration, of a driveshaft equipped with a tripod joint and a constant velocity joint of the fixed type. This mechanical transmission is used, for example, in automobiles to connect each half shaft of the differential to a driving wheel. After highlighting that the usual approach to evaluating the instantaneous transmission ratio is conceptually flawed, the paper proposes an original procedure to correctly assess the transmission ratio. The paper also proves that the considered driveshaft is homokinetic whenever the axes of the two end shafts are parallel. Numerical examples show application of the proposed procedure to case studies. [ABSTRACT FROM AUTHOR]

Exploring the motion characteristics in thread rolling process under varied center distance between rotation axes of workpiece and rolling die is important for accuracy evaluation and process control, and provides a basis for further study on motion compatibility condition in the thread and spline synchronous rolling process. The motion characteristics between the die and workpiece under varied center distance in the thread rolling process were investigated. Related mathematical models in the rolling process, such as the rotation angle and the angular velocity for workpiece, the transmission ratio, and the axodes of workpiece and die, were established. The results indicated that: (1) the relationship between rotation angle of workpiece and rolling time is approximately linearly dependent, transmission ratio almost presents the same change as angular velocity of workpiece; (2) the cross sections of the axodes of workpiece and rolling die are similar to Archimedes line, where the polar radius reduces with the reduction of center distance; (3) however, the changes of the angular velocity of workpiece, the transmission ratio, and the axodes are closely related to the shape of tooth profile. [ABSTRACT FROM AUTHOR]

This paper presents a study on a novel passively variable transmission (PVT) which is capable of operating in a wide range of transmission ratios. The developed device is light, bidirectional, and compliant, which is achieved by incorporating a twisted string actuator (TSA) in it. TSA is a cheap and mechanically simple actuator, in which twisted strings contract as a result of twisting and therefore act as a linear transmission. If one introduces a physical offset between the twisted strings, this changes the ratio between the output speed and force provided by the actuator. By introducing a passive element that changes the offset between the strings depending on the magnitude of external load force, we developed a PVT which inherited the advantages of conventional TSAs. This paper describes the basic operation principle and presents mathematical model and experimental evaluation of the proposed variable transmission mechanism. Advantages such as light weight, compliance, and passive bidirectional adjustment of transmission ratio make the proposed device attractive for implementation in various areas of haptics, teleoperation, and wearable and lightweight robotics. [ABSTRACT FROM AUTHOR]

Based on the coaxial HPGHP system experiments, the mathematical model of the various components of the coaxial HPGHP system is established to research the matching relations between the drive system and the load demand of the compressor. This paper establishes the thermal efficiency of the engine model based on load rate, to maintain the thermal efficiency always be above 0.25, combined with the thermal efficiency map of the engine, the best economic zone of engine operation is determined. Finally, Torque optimization model of the coaxial HPGHP system was proposed, the transmission ratio of the HPGHP system was optimized and mode control strategy of the coaxial HPGHP system was determined. Simulation results show the thermal efficiency of the HPGHP system can be always been guaranteed above 0.25 and the transmission ratios are respectively 2.9, 1.8 and 1.4 in three different load demand range. [ABSTRACT FROM AUTHOR]

Highlights: [•] Used visual spectral analysis technology to determine changes of black tea added with different additives. [•] Took comparison analysis method as main method to get the difference of three additives added in tea. [•] The strength of absorption spectrum and the moving of peak value reflect the degree of influence on tea. [Copyright &y& Elsevier]

Abstract: The objective of the present work was the conjoint analysis of the efficiency and transmission ratio ranges that can be achieved with all the possible constructive solutions of four-, five-, and six-link planetary gear trains. We started from the graphs of these trains to determine all the structurally distinct kinematic inversions. We then obtained all the constructive solutions resulting from every possible combination of gear type and configuration. The result was thus the set of structurally and constructively different planetary gear trains. Next, we obtained the range of transmission ratio that can be achieved with each train, and the efficiency as a function of the transmission ratios within that range. This analysis revealed which trains allow both high transmission ratios and high efficiency, and are thus potentially most useful in the design of power transmission applications. They included a series of high efficiency trains whose potential utility had not as yet been investigated. Additionally, the study led to some interesting conclusions about the relationship between efficiency and transmission ratio in six-link planetary gear trains. [Copyright &y& Elsevier]

Abstract: Transmission of single-cell and spinning detonation waves in C2H4 +3(O2 + βN2) mixtures through a 2-D sudden expansion experimentally studied using high-speed cinematography and soot film visualization. Nitrogen dilution ratio, β, is utilized to control cell size and detonation mode. Detonation wave of ethylene/oxygen/nitrogen mixture was initiated via DDT in the 1mm×1mm cross-section and 250mm long initiator channel before propagating into the 3mm×1mm receptor channel. Visualizations show that detonation waves were extinct and accompanied with abrupt decrease in visible reaction front propagating velocities right after passing through the sudden expansion. However, re-acceleration of the reaction front and re-initiation of the detonation wave were observed downstream in the expanded receptor section. Two re-initiation modes with large disparity in the re-initiation distance were experimentally characterized. For mixtures with nitrogen dilution ratio equals 0.3 or less, the cellular detonation front propagated with single cell in the initiator section before entering the sudden expansion. The re-initiation distance was less than 50mm and was likely achieved via shock reflection. Velocity characterization shows that steady propagating speed of the detonation wave is ∼100m/s higher in receptor section than in the initiator section. Since the cell size became larger than 1mm for mixtures with β ⩾0.3, the detonation wave propagated in spinning detonation mode before transmitting into the expanded section. The reaction front would have to go through another DDT process to reach detonation state in the receptor section, and the re-initiation distance was increased to more than 150mm. Moreover, step height of the sudden expansion was proposed as the characteristic length scale to obtain a unified non-dimensional correlation between re-initiation distance and detonation cell size. [Copyright &y& Elsevier]

Abstract: Glan–Taylor prism is the key component of the static polarization interference imaging spectrometer. In this paper, we consider the case that optical axes of the Glan–Taylor prism have departure angles from their ideal directions that in the principal section, however principal section varies with optical axes. Ray tracing method is employed to detailedly present the light trails in the birefringent Glan–Taylor prism when the incident plane and the principal section are in the same plane. Both double refraction in the crystal and internal double reflection over the interface between the birefringent and isotropic mediums are analyzed in detail. Besides, we obtain the approximate formula about the transmission ratio of Glan–Taylor prism. Finally, the transmission ratio of Glan–Taylor prism due to the deviations of the optical axes is deduced and discussed in particular. [Copyright &y& Elsevier]

Abstract: This paper proposes an analytical approach to the robust design of mechanisms, to achieve motion and accuracy requirements given a desired transmission ratio and allowable geometrical variations. The focus is on four-bar and slider-crank mechanisms, which are common elements for the transmission of rotary motion, especially over distances, which are too big for the use of conventional elements such as gears, and motion along a predefined guide-curve, which often is a straight line. For many power transmission applications, a constant relation between the motions of an input and corresponding output element is required. For a four-bar linkage, a value of 1 is the only possible constant transmission ratio—achieved when the mechanism has a parallelogram configuration. In the case of a slider-crank linkage a constant transmission ratio can be achieved with a properly designed circular guide-curve, which makes the slider-crank essentially equivalent to a four-bar. In practice, however, as a result of variations in link lengths due to manufacturing tolerances and load-induced or thermal deformations, the transmission ratio for a parallelogram four-bar linkage will deviate substantially from its ideal theoretical value of 1. Even small changes in link lengths due to deformations or joint backlash can cause unacceptable instantaneous transmission ratio variations. The concepts presented are not limited to the design of four-bars and slider-cranks but can also be applied universally in the design of other mechanisms. [Copyright &y& Elsevier]

Abstract: The optical properties of PbMg1/3Nb2/3O3(PMN) single crystals in the wavelength range of 300–1700nm have been investigated using Variable Angle Spectroscopic Ellipsometer (VASE). The refractive indices and extinction coefficients have been obtained. The optical band gap energy of PMN single crystal was derived to be about 3.41eV. The Sellmeier optical coefficients E 0, λ 0, S 0, and E d were calculated by fitting the single-term oscillator equation. The transmission ratio of PMN single crystal ranging from 200 to 2200nm has also been investigated using UV–visible–NIR spectrometer. The transmission ratio is above 60% in near IR region and the reflection loss is calculated to be about 20%. [Copyright &y& Elsevier]

Abstract: An explosion in a borehole or an accidental explosion in a tunnel will generate a two-dimensional (2-D) compressive wave that travels through the surrounding rock mass. For the problem of 2-D compressive wave propagation in a rock mass with parallel joints in the radial direction normal to the joints, parametric studies on the transmission ratio and the maximum rebound ratio are performed in universal distinct element code. The variation of the transmission ratio with the ratio of joint spacing to wavelength is generalized into a characteristic curve, which can be used as a prediction model for estimating the transmission ratio. The relationship between the maximum rebound ratio and the influence factors is obtained in charts. The charts can be used as a prediction model for estimating the maximum rebound ratio. The proposed prediction models for estimating the transmission ratio and the maximum rebound ratio are applied to a field explosion test, Mandai test in Singapore. The minimum possible values of peak particle velocity (PPV) at the monitoring points are estimated by using the proposed prediction model for estimating the transmission ratio along the radial direction normal to the joints. On the other hand, the maximum possible values of PPV are estimated by using the proposed prediction model for estimating the maximum rebound ratio along the same radial direction. The comparison shows a good agreement between the field-recorded PPVs and the estimated range of PPVs given by the minimum possible PPVs and the maximum possible PPVs at the monitoring points in Mandai test. The good agreement between the estimated and field-recorded values validates the proposed prediction models for estimating peak particle velocity in a rock mass with a set of joints due to application of a compressive wave at the boundary of a tunnel or a borehole. [Copyright &y& Elsevier]

Concrete structures inevitably suffer from dynamic loadings, causing damage and uncomfortable vibration. Improving the damping of concrete to passively absorb the vibration energy is beneficial to mitigate the hazards and improve comfort. However, at least two challenges must be completed before applying this strategy, namely, preparing effective energy dissipating concrete and estimating the damping parameter of its elements and structures. In this study, rubberized recycled aggregate concrete (RRAC), prepared with coarse recycled concrete aggregate (RCA) and recycled rubber aggregate (RRA) instead of natural aggregate, is experimentally validated to show higher damping. Besides, a universal function of energy dissipation over strain amplitude is established for concrete containing natural aggregate, RCA, and RRA. Based on the found strain–energy dissipation function and finite element analysis, an iterative method of estimating the inner damping ratio of RRAC elements from the material damping is proposed and validated. Through the proposed method, the effects of loading amplitude, loading frequency, and stress history on the nonlinear damping behaviors of RRAC beams are numerically analyzed. The experiment result and the proposed damping determination method can encourage the application of recycled building materials in structural engineering, especially in projects with requirements of vibration control. • High-damping concrete is prepared by combining RRA and RCA as aggregates. • Strain–energy dissipation function is established for different concrete. • Material damping of RRAC beam is estimated based on the found function and FEA. [ABSTRACT FROM AUTHOR]

• The Wind Energy Fan (WEF) has high-efficient utilization of wind energy. • The performance of Wind Energy Fan with lift-type wind turbine and Drag-type was studied and compared. • WEF-System with Drag-type wind turbine is easier to start up than with lift-type wind turbine. • WEF-System with Lift-type wind turbine of 3 blades is relatively optimal. The Wind Energy Fan system (WEF-System) can realize the efficient ventilation in underground engineering by utilizing wind energy to drive the axial fan with the vertical wind turbine directly. The wind turbine in WEF-System is a key equipment to catch the wind energy, its performance affects the ventilation performance of WEF-system directly. In this study, based on the characteristic analysis of vertical axis wind turbine, an experiment platform with the corresponding test system was established and the wind turbine was optimized to improve the ventilation performance of WEF-System by the type and the blade number. Experimental results showed the duct ventilation volumes for WEF-System with Lift-type wind turbine are 9.6 %∼25.3 % and 9.6 %∼15.2 % larger than those with Drag-type wind turbine under transmission ratios of 1:5.17 and 1:10, respectively. With increasing the blade number of Lift-type wind turbine, the duct ventilation volume of WEF-System reduces and WEF-System with Lift-type wind turbine of 3 blades is relatively optimal. This WEF-System is proved to an effective wind energy technology to realize the active utilization of wind energy in underground ventilation. [ABSTRACT FROM AUTHOR]

• A new ventilation method in the underground engineering is proposed. • The Wind Energy Fan (WEF) has high-efficient utilization of wind energy. • The influence rules of the peed increaser are revealed. • A method is proposed to match the vertical wind turbine and the axial fan. Wind energy is heavily utilized due to its clean renewability, large reserves and wide distribution. Wind energy is also the main driving force for natural ventilation, but it is very difficult to realize natural ventilation directly in the underground engineering. This study proposed an integrated device called Wind Energy Fan (WEF), which utilizes wind energy to drive the fan linked with the wind turbine directly by a transmission shaft, and this vertical wind turbine can realize the underground ventilation. An experiment platform was established to test the WEF performance with the consideration of three transmission ratios and two kinds of wind turbines with 3 and 5 blades. Results showed that the transmission ratio has a pronounced influence on the fan air volume and should be selected to obtain the rated air volume. The wind turbine with 3 blades is easier to start and its air volume is also 5.43%–17.85% more than that with 5 blades. According to the aerodynamic characteristic curves of the vertical wind turbine and axial fan, their matching method is proposed on the power and the speed. This scheme is an effective wind energy technology to realize the active utilization of wind energy in the underground engineering. [ABSTRACT FROM AUTHOR]