In order to take advantage of different forms of heat pumps and to mitigate thermal imbalance underground caused by long-term operation of ground source heat pumps, hybrid ground source heat pump systems have received an increasing attention. In this research, based on the fact that abundant groundwater resources are commonly available in karst regions, a new strategy is introduced for selecting and

Extreme haze was often observed at many locations in Beijing-Tianjin-Hebei region within several hours when they occurred, which is referred to as extreme co-movements and extreme dependence in statistics. This article applies tail quotient correlation coefficient to explore the temporal and spatial extreme dependence patterns of haze in this region. Hourly PM2.5 station-level data during 2014-2018

Considering the multiple effects of product greenness and carbon emission trading, this article constructs a differential game model to study the collaborative innovation between enterprises in a green supply chain composed of one manufacturer and one supplier. This article examines the optimal green technology innovation strategies, optimal revenues of manufacturers and suppliers as well as the overall

The fatality rate can be dramatically reduced with the help of emergency medical services. The purpose of this study was to establish a computational algorithm to predict the injury severity, so as to improve the timeliness, appropriateness, and efficacy of medical care provided. The computer simulations of full-frontal crashes with rigid wall were carried out using LS-DYNA and MADYMO under different

The research on the sealing problems is of great significance in the design of turbines and aircraft engines, with the constant pursuit of high thrust ratio and low fuel consumption. A large number of experimental studies give information that the brush seal not only has good sealing characteristics, high sealing efficiency, but also has low manufacturing cost and simple structure.1–6 The leakage of

The past decades have witnessed a great advance in studies of switched systems which are widely applied in robot systems,1 networked systems,2 chemical process3 and so on. Switched systems, which comprised multiple subsystems and a signal deciding to activate one of them, can effectively model processes or multiple-mode systems. Moreover, the idea of controller switching is carried over to many intelligent

Hydrodynamic effects of mussel farms have attracted increased research attentions in recent years. The understanding of the hydrodynamic impacts is essential for predicting the sustainability of mussel farms. A large mussel farm includes thousands of mussel droppers, and the combined drag on the mussel droppers is sufficient to possibly affect the longevity of the entire long-lines. This article intends

The purpose of this study was to evaluate the functional and cosmetic outcomes of a new modified Fox pentagon technique performed using polytetrafluoroethylene in frontalis suspension surgery for blepharophimosis syndrome. This retrospective study enrolled 40 patients diagnosed with blepharophimosis syndrome from March 2016 to October 2018. All patients underwent frontalis suspension using a new modified

Rotary lip seal is used in various applications where the rotation shaft needs to be sealed, such as hydraulic pumps, fuel pumps, camshafts, crankshafts, and so on. Many thermal elastohydrodynamic lubrication models of rotary lip seal have been introduced, and most of these models neglect the asperity contact. This article proposes a mixed thermal elastohydrodynamic lubrication model of rotary lip

In order to study the heat transfer characteristics between two rough surfaces of two contacting blocks with different bulk temperatures and sliding reciprocating motion, a two-dimensional heat transfer model was used to analyze the dimensionless average heat flux, considering thermal contact conductance. The results of a series simulations were presented, covering a wide range of operating parameters

The beam pumping unit is widely used in oil fields as an oil extraction machine. However, due to its structural characteristics and the changing conditions of underground reservoirs, there are many factors affecting the efficiency of the beam pumping unit. How to quickly and accurately reflect the inefficient factors, and whether the efficiency of the pumping unit is reasonable, it is an urgent problem

Biofilm formation of pathogenic bacteria in medical devices plays an important role in the development of chronic infections. The increased use of medical implants in health care is strongly associated with elevated biofilm-related infections. S. aureus is one of the most frequent agents causing hospital-acquired catheter-related bloodstream infections (CRBSI) associated with biofilm formation.1 In

Parallel kinematic machines (PKMs) have received significant attention both in terms of theoretical research and practical applications due to their merits of high loads, high accuracy, and high speed when compared with serial kinematic machines (SKMs). The typical success can be verified by the application of the Tricept and Sprint Z3 in assembly and milling in aerospace and automotive industry.1–4

In recent years, with increasingly serious energy and environmental issues, emission regulations have become stricter worldwide. Due to this fact, turbocharged engines have become more common because of their high volume of power output, low consumption, and low emissions. However, the better performance comes at a price because turbochargers operate at high speeds, usually hundreds of thousands of

In the industry of oil and gas, erosion triggered by solid particle is commonly seen in pipe system and it is regarded as a severe problem.1 In actual practice, sand is often found in pipelines and it would sometimes impinge the pipe wall, valves, and the other equipments.2,3 Therefore, the continual emergence of erosion damages in pipelines have led to one of the dominating hazards in the field.4

Pedestrians are common victims of traffic accidents in China, and pedestrian fatalities account for nearly a quarter of deaths in traffic accidents.1 While the number of automobiles is increasing rapidly at present. As a result, the incidence of traffic-related pedestrian deaths also increases every year. So, researches on vehicle–pedestrian crash reconstructions and pedestrian injury biomechanics

In recent years, with the continuous improvement and perfection of performance of permanent magnet materials, permanent magnet synchronous motor (PMSM) has gained rapid development. Owing to its simple structure, small size, high power factor, high torque–current ratio, low moment of inertia, easy heat dissipation and maintenance, it is widely applied in electric vehicles, robots, household appliances

With the wide application of high-speed and heavy-load palletizing robots in automobile, metallurgy, and logistics industries, automated production lines put forward higher requirements for the speed, load capacity, acceleration, and positioning accuracy of robots. The high-speed and heavy-load palletizing robot not only reduces the positioning accuracy of the palletizing robot but also limits the

Medical needles are widely used in medical treatment for injection or blood sampling purposes.1–3 When the needle is inserted into a human organ, an insertion force is generated between the needle and the organ tissue. This force may influence the needle inserting direction3–5 or increase pain.5–10 Therefore, it is important to reduce or minimize it for achieving better medical treatment. The sharpness

The long-term practices of developed countries show that developing multimodal transport is not only conducive to alleviating public problems such as energy depletion and environmental damage caused by transportation but also helpful in reducing transport costs, improving transport efficiency, and optimizing transport services. On 27 June 2018, the State Council of China issued the 3-year Action Plan

Breast cancer, as one of the most malignant tumors, poses a serious threat to the lives of females. Nucleotide exchange factor SIL1 is an important regulator of endoplasmic reticulum function that might have a specific role in tumor progression. In this study, we aimed to investigate the effect of SIL1 on the proliferation, apoptosis, and metastasis of human breast cancer. SIL1-specific small interfering

To evaluate the influence of low-concentration contrast agents and low-tube-voltage computed tomography on chest enhancement examinations, we conducted a multicenter prospective study. A total of 216 inpatients enrolled from 12 different hospitals were randomly divided into four groups: A: voltage, 120 kVp; iohexol, 350 mgI/mL; B: voltage, 100 kVp, iohexol, 350 mgI/mL; C: voltage, 120 kVp, iodixanol

In recent years, selective catalytic reduction (SCR) has become the mainstream after-treatment technology to reduce oxides of nitrogen (NOx) emission of diesel exhaust.1–6 The system uses a urea water solution (UWS) as the reductant to convert NOx in the exhaust to N2 and H2O by using a catalyst.7 The UWS plays a crucial role for NOX conversion,8,9 which is a corrosive liquid that freezes below −11°C

In bridge health monitoring, monitoring of the dynamic response of the bridge can provide important data, such as the natural frequency, damping, or mode shape, which can be used for bridge model updating or damage identification.1–8 Traditionally, to monitor the dynamic responses of a bridge, a fiber Bragg grating (FBG) accelerometer,9 a force balanced accelerometer,10,11 or a wireless accelerometer12

For a long time, traditional motors have received widespread attention and research, but they can only achieve single-degree-of-freedom rotation.1 In complex transmissions, the mechanical devices and multiple single-degree-of-freedom motors are required to complete multi-degree-of-freedom motion.2 The motor in the coupling control system of this type tends to be bulky, slow in response, and poor in

With the rapid development of economy, the urban motor vehicle population in the world is growing rapidly. The number of traffic accidents is also on the rise in China.1,2 According to the road traffic safety research institute of the ministry of public security, China’s urban road traffic accident accounts for 45.8% of the country’s road traffic accidents in 2018, and the number of casualties in urban

In the actual gas phase and liquid phase transport, the fluid in the pipeline generally contains a certain amount of solid particles, which is the main reason for the erosion of the pipeline. While in the pipeline system, elbow is considered as a key component, mainly because the elbow is under complicated forces, which leads to high stress. And elbow is the most vulnerable part to erosion, which has

Respirable particulate matter, such as PM2.5, can cause harmful effects on the body’s respiratory system. The primary sources of particulate matter include combustion of fossil fuel, industrial sources, automobile emission, and biomass burning.1 At present, fibrous media has been extensively used in industry and home, since it has excellent filtration efficiency to remove fine particulate matter from

A cavity is a common structure in an aircraft structural and mold design. It is usually processed by a robot or computer numerical control (CNC) milling.1–3 Aircraft structural parts are usually large in size and multi-cavity (the overall size can reach 4000 mm × 2000 mm); in this instance, cavities tend to be far apart from each other. In addition, the robot tool path planning of multi-cavity parts

With excellent mechanical properties, carbon fibre–reinforced composites are widely used in many engineering structures. So many researchers have studied static failure feature of carbon fibre–reinforced composites, which could be influenced by ply angle,1 environmental condition2 and moulding technology.3,4 With broad application of composites, composite structure is more and more complicated, and

For the characteristics of allowing constructing tunnels in adverse geological conditions including difficult ground conditions as well as tunnels in vulnerable urban areas, tunnel boring machine (TBM) has well-established tunnel construction method recently.1,2 When a tunnel is being excavated, the following two steps in the shield machine are conducted alternatively: the tunneling of the TBM by all

In the face of the dual crises of energy and the environment, hybrid electric vehicles (HEVs) are being in the process of gradually replacing traditional fossil-fueled vehicles. As is well known, HEVs can use the electrical power stored in the battery to propel the vehicle; thus the energy management strategy (EMS) controlling the engine and electrical power-split flows are crucial for reducing fuel

The vehicle suspension system is the fundamental device for improving ride comfort and handling stability.1–4 Recently, researchers found that the energy of the suspension vibration can be regenerated by means of magnetic suspension5–11 and piezoelectric suspension.12–16 In Segal and Lu,17 the influence of suspension damping, tires, and road surface roughness on the vehicle running resistance was analyzed

As one of the important parts of intelligent vehicle system, automatic steering system (ASS) can make intelligent vehicle to accurately track the desired unmanned vehicle trajectory via onboard sensors such as vision system1,2 or the Global Positioning System,3 which provide feedback signals. The field of automatic steering control system is well established, and the available literature on the topic

Because of the development of electro-hydraulic servo technology,1–3 multiple hydraulic valves have been widely used to drive an actuator in parallel, and scholars have achieved favorable results by using this method in some engineering applications.

In this article, we propose a dual-servo micro-feed mechanism based on the motion synthesis principle. The motor-driven ball screw and motor-driven ball nut of two quasi-equal areas can realize a micro-feed mechanism. The rotary nut and ball screw pair is the key component of movement and force transmission, and their dynamic performance directly determines the precision of the micro-feed mechanism;

A solar cavity receiver is an essential apparatus to achieve solar-thermal conversion in a solar thermal power tower station. Its basic structure is shown in Figure 1. In the solar cavity receiver, several evaporating heating surfaces and superheating surfaces that consist of single parallel panel or multiple parallel panels are arranged in the solar cavity receiver. Evaporating heating surfaces are

In today’s increasingly serious energy issues, it is particularly important to carry out research on energy conservation and emission reduction. Pump as turbine (PAT) is a kind of energy-recovery equipment, which can recover the residual energy in the technological fields of fertilizer, water distribution network,1–3 water desalination, and petro-chemical industry,4 as well as many other processes

Air-breathing hypersonic vehicle (AHV) is a new type of aerospace vehicle that can fly for a long distance at five times the speed of sound in large airspace, flying at an altitude of 20–100 km in near space.1,2 AHV combines many advanced technologies of modern science and technology, and it has the advantages of spacecraft and aircraft. It is an important direction of future aircraft development.

The thinning spinning has the advantages of complete structure, good comprehensive performance, high material utilization rate and short spinning stroke, and so on. It has become one of the preferred manufacturing methods for thin wall tubes used in aviation, aerospace, and nuclear power fields. In the spinning process of an ultra-thin wall cylinder, the combination of simulation and experiment and

In the last decades, two-degrees-of-freedom robots (TDFRs) are widely applied for imitating the motions of the natural creatures with multi-joints whose rhythmic motions depend on the synchronized locomotion of their joints.1–5 Therefore, to imitate coordinated swinging or walking of the multi-joints natural creatures, each joint of the TDFRs needs to be movement synchronized with other coupled joints

The flight safety and punctuality rate exist serious risks because of the aircraft ground icing in bad weather. Aircraft ground deicing can avoid flying accidents and easing flight extensive delays caused by the aircraft icing on the ground, and it is widely used at home and abroad. As people travel efficiently, the efficiency of aircraft deicing on the ground and the safety of flight in ice and snow

Cavitation phenomenon reduces hydraulic performance and creates vibration and noise, which seriously affects the safety and stability of system operation.1,2 The configuration of cavitation can be divided into five categories: bubble cavitation, sheet cavitation, cloud cavitation, super cavitation, and vortex cavitation. Considering the intense unsteady flow characteristics of cavitation, cloud cavitation

With the starts of large-scale civil aircraft project, the development of new fuselage structure is an effective means to improve fuselage life, economy, safety, comfort, and reliability of large passenger aircraft. Aircraft tire is a very important component which requires high safety and reliability. The safe taking off and landing of aircraft must be accomplished by the unique functions of aviation

The near-space solar-powered unmanned aerial vehicles (SP-UAVs) harvest solar energy throughout the day, storing energy inside the energy storage batteries (such as lithium sulfur battery) and using the stored energy for night cruising. Having the advantages of high altitude long-endurance (HALE) performance, being less affected by the tropospheric weather, and multiple mission payloads, the SP-UAVs

At present, in the boom of the promotion of new energy vehicles, electric vehicles have attracted much attention due to their advantages in emissions, structure, and technology.1 However, the problem of the cruising range of electric vehicle has not been effectively solved, and it has become an obstacle to market promotion.2–4 The electric vehicle drives the wheels by the motor, and at the same time

Energy consumption and environment protection have become increasingly important, and thus are drivers for developing energy-saving and environment-friendly vehicles. New energy vehicles1,2 and hybrid powertrain vehicles3–5 are the main solutions. However, new energy vehicles have not found an acceptable solution with safety, stability and low cost. The hybrid powertrain vehicle has become a concerned

Fiber-reinforced composites have excellent mechanical properties, good thermal stability, and capability on weight reduction, which are widely used in aeronautics, astronautics, automotives, naval vessels, and weapons industry.1,2 Currently, there are a large number of such composite thin walled structures, such as solar panels, aircraft engine fan blades, and large wind turbine blades. The vibration

The study of critical negative rake angle (CNRA) with a large RNA tool, as well as that of the minimum uncut chip thickness (MUCT) with the rounded-edge cutting tool in micro-cutting, is aiming for establishing the relationship between the effective negative rake angle (ENRA) of the tool and cutting process parameters in cutting and ploughing critical state. Therefore, the CNRA of large negative rake

At present, in the construction process of highway subgrades, builders often encounter the phenomenon of stress concentration caused by an insufficient subgrade soil layer, which causes early damage to the pavement structure. In engineering, a common technique is the use of lime to treat bad subgrade sections to improve the soil-based elastic modulus. The effect of the treatment has been recognized

Magneto-rheological fluid (MRF) is one type of smart material with solid–liquid two-phase, and its morphology and properties are constrained and regulated by external magnetic field. With the continuous, reversible, rapid, and easy to control rheological properties, it makes MRF have a broad range of applications including the fields of aerospace, automotive industry, hydraulic transmission, sealing

Unmanned aerial vehicle (UAV) has attracted wide attention from scholars all over the world in past decade. UAV has the advantages of small size, low cost, convenient use, low requirements for the operational environment, flexible, no casualty risk, and so on. It is widely used in aerial photography, plant protection, express transportation, disaster rescue, surveying and mapping, power inspection

As important two-dimensional (2D) lightweight cellular materials with excellent cushioning performance, the multi-layer regularly arranged circular honeycombs (MRACHs) are always widely applied in the fields of construction, vehicle manufacturing, military affairs, aviation, packaging, and so on. Some theoretical, finite element (FE) and experimental investigations have been carried out for the elastic

The application of distributed drive technology in heavy vehicle could bring greater benefits than passenger car. Since the clutch, transmission, transfer case, differential, drive shaft, and other mechanical components are removed, it simplifies the vehicle structure and makes its layout more convenient. In addition, each wheel is controlled by the wheel hub motor independently to increase the vehicle’s

There are thousands of large-aperture optics installed in high-power laser facilities coated with SiO2 sol–gel film, such as windows, lenses, crystals, gratings, shields, and so on. However, contact contamination from film debris introduced by manual assembly is severely destructive for all high-power laser components.1,2 Spaeth et al.3 found that the contamination on the surface of optical component

Ultra-precision patterned microstructures, including freeform surfaces by superimposing microstructures, are widely adopted in optical applications, such as three-dimensional (3D) imaging, micro-optical telescopes, confocal microscopy, endoscope systems, and machine vision,1–5 to realize the specified optical performance and a compact system. Such kind of compound surfaces can be fabricated through

High-speed parallel robots are widely used in industrial production lines, such as food industry, pharmaceutical industry, and electronics industry. They are mainly used to complete high-speed sorting, packing, stacking, and assembly. However, the high-speed parallel robots with less degrees of freedom (DOF) cannot meet the complex industrial production requirements. Therefore, the application of 6-DOF

The face gear is a widely researched new transmission mechanism. This mechanism can be widely used in the special transmission area, especially in the field of aviation. Since the contour of the face gear is complex, it cannot be modeled directly. The most common method of mechanical transmission is that of gear transmission, in which the tooth surfaces contact each other to transmit power, although

Prevalence of composites is found in the industrial field of aircraft, transportation, and marine owing to their superior material properties.1 However, since the composite laminates often lack the through-thickness reinforcement that can subject to impact in the transverse direction, such structure has low transverse damage tolerance.2 For low-velocity impacts in the composite, laminated structures

Reliability modeling and assessment are critical issues for complex engineering systems. It is challenging to accurately assess the reliability for such systems because of many factors such as the failure competing or dependencies, impact from external environments, and epistemic uncertainty associated with parameters of component failure/degradation models. According to the failure mechanism, most