Design and laboratory evaluation of fog-sealed chip seal on epoxy asphalt pavement for steel bridge deck

In order to improve the surface performace of epoxy asphalt pavement （EAP） for steel bridge deck, an epoxy asphalt chip seal （ ECS） covered by a cationic emulsified asphalt fog seal （i. e., fog-sealed chip seal） isproposed and a laboratory study is conducted to design and evaluate te fog-sealed chip seal. First, the evaluation indices and methods of te chip seal on steel bridge deck pavement were proposed. Secondly, the worst pavement conditions during te maintenance time were simulated by te small traffic load simulation system MMLS3 and the short-term aging test for minimizing the failure probability of chip seal. Finally, the design parameters of fog-sealed chip seal were determined by the experimental analysis and the performance of the designed fog-sealed chip seal was evaluated in thelaboratory. Results indicate that the proposed simulation method of pavement conditions is effective and the maximal load repetitions on the EAPslab specimen are approximately 925 300 times. Moreover, the designed fog-sealedchip sealcan provide a dense surface with sufficient skid resistance,aggregate-asphalt aahesive performance and interlayer shearing resistance.

Laboratory Simulation of the Formation Process of Surface Geochemical Anomalies Applied to Hydrocarbon Exploration

The formation mechanisms and processes of geochemical anomalies used as proxies in surface geochemistry exploration （SGE） have not been well understood. Previous studies cannot realize 3D measurement of microseeping hydrocarbons from reservoirs to the surface, which made it difficult to understand the features and pathways of deep hydrocarbon microseepages. Understanding the processes of hydrocarbon microseepages will contribute to the acceptance and effectiveness of surface geochemistry. Based on a simplified geological model of hydrocarbon microseepages, including hydrocarbon reservoir, direct caprock, overlying strata and Quaternary sediments, this work established a 3D experimental system to simulate the mechanisms and processes of deep hydrocarbon microseepes extending to the surface. The dispersive halos of microseeping hydrocarbons in the subsurface were adequately described by using this 3D experimental system. Results indicate that different migration patterns of hydrocarbons above the point gas source within the simulated caprock and overlying strata can be reflected by the ratio of i-butane to n-butane （i-C4/n-C4）, which follow diffusion and infiltration （buoyancy） mechanisms. This is not the case for vertical measurement lines far from the point gas source. A vertical gas flow in the form of a plume was found during hydrocarbon microseepage. For sampling methods, the high-density grid sampling is favorable for delineating prospecting targets. Hydrocarbon infiltration or buoyancy flow occurs in the zones of infiltration clusters, coupling with a diffusion mechanism at the top of the water table and forming surface geochemical anomalies. These results are significant in understanding hydrocarbon microseepage and interpreting SGE data.

Experimental Study on the Variation of Optical Imaging Characteristics with Zenith Angle due to Internal Solitary Waves in Sunglint

Internal solitary waves(ISWs)change the roughness of the sea surface,thus producing dark and bright bands in optical images.However,reasons for changes in imaging characteristics with the solar zenith angle remain unclear.In this paper,the optical imaging pattern of ISWs in sunglint under different zenith angles of the light source is investigated by collecting optical images of ISWs through physical simulation.The experiment involves setting 10 zenith angles of the light source,which are divided into area a the optical images of ISWs in the three areas show dark-bright mode,single bright band,and bright-dark mode,which are consistent with those observed by optical remote sensing.In addition,this study analyzed the percentage of the dark and bright areas of the bands and the change in the relative gray difference and found changes in both areas under different zenith angles of the light source.The MODIS and ASAR images display a similar brightness-darkness distance of the same ISWs.Therefore,the relationship between the brightness-darkness distance and the characteristic half-width of ISWs is determined in accordance with the eKdV theory and the imaging mechanism of ISWs of the SAR image.Overall,the relationship between them in the experiment is almost consistent with the theoretical result.

Numerical and Experimental Study of the 3D Effect on Connecting Arm of Vertical Axis Tidal Current Turbine

Vertical axis tidal current turbine is a promising device to extract energy from ocean current. One of the important components of the turbine is the connecting arm, which can bring about a significant effect on the pressure distribution along the span of the turbine blade, herein we call it 3D effect. However, so far the effect is rarely reported in the research, moreover, in numerical simulation. In the present study, a 3D numerical model of the turbine with the connecting arm was developed by using FLUENT software compiling the UDF（User Defined Function） command. The simulation results show that the pressure distribution along the span of blade with the connecting arm model is significantly different from those without the connecting arm. To facilitate the validation of numerical model, the laboratory experiment has been carried out by using three different types of NACA aerofoil connecting arm and circle section connecting arm. And results show that the turbine with NACA0012 connecting arm has the best start-up performance which is 0.346 m/s and the peak point of power conversion coefficient is around 0.33. A further study has been performed and a conclusion is drawn that the aerofoil and thickness of connecting arm are the most important factors on the power conversion coefficient of the vertical axis tidal current turbine.

Laboratory studies on the infectivity of human respiratory viruses:Experimental conditions,detections,and resistance to the atmospheric environment

The environmental stability of infectious viruses in the laboratory setting is crucial to the transmission potential of human respiratory viruses.Different experimental techniques or conditions used in studies over the past decades have led to diverse understandings and predictions for the stability of viral infectivity in the atmospheric environment.In this paper,we review the current knowledge on the effect of simulated atmospheric conditions on the infectivity of respiratory viruses,mainly focusing on influenza viruses and coronaviruses,including severe acute respiratory syndrome coronavirus 2 and Middle East respiratory syndrome coronavirus.First,we summarize the impact of the experimental conditions on viral stability;these involve the methods of viral aerosol generation,storage during aging and collection,the virus types and strains,the suspension matrixes,the initial inoculum volumes and concentrations,and the drying process.Second,we summarize and discuss the detection methods of viral infectivity and their disadvantages.Finally,we integrate the results from the reviewed studies to obtain an overall understanding of the effects of atmospheric environmental conditions on the decay of infectious viruses,especially aerosolized viruses.Overall,this review highlights the knowledge gaps in predicting the ability of viruses to maintain infectivity during airborne transmission.

Building towards Expertise in CME （Continuous Medical Education）： Suggestions for a New Paradigm

To build towards expertise, one has to accept to modify his way of practicing, including： （1） a need to reflect on and about the action; （2） a continuous concern about our competence to practice; （3） tireless effort to combine metacognition and mental practice in a trans-disciplinary approach; （4） adding research with neuroscience, understanding neuroplasticity, modulation and artificial intelligence. Usual practice actually does not include a continuous concern for CME （continued medical education） and is intermittent at best. This new paradigm constitutes the basis of our approach. Expertise starting in 2015 is described as an asymptotic curve unable to be obtained with usual practice and intermittent education. We suggest a new way of conceiving CME combining practice, reflection on action and in-situ simulation laboratory near work. We are describing TEE （technology-enhanced education） coupled with certain neuro-enhancers to achieve a break in the asymptotic curve of expertise. This is in reality a new conception of CME in medicine.

Simulating System for the Investigation of Mechanical Malfunctions Appeared in a Twin AC Drive Used in Cement Industry

In order to investigate the dynamic behavior, to study a variety of operational problems, to apply different control techniques and to suggest functional improvements of a high power electromechanical system, a pilot study on a low power laboratory simulating system is proposed in this paper. Particularly, to investigate operational problems of a twin AC drive with asynchronous machines used for cement kilns, an under-scale laboratory simulating system has been developed and experimental results are being presented in this research work.

Evaluation of laboratory and environmental exposure systems for protein modification upon gas pollutants and environmental factors

Chemical modifications of proteins induced by ambient ozone(O_(3))and nitrogen oxides(NOx)are of public health concerns due to their potential to trigger respiratory diseases.The laboratory and environmental exposure systems have been widely used to investigate their relevant mechanism in the atmosphere.Using bovine serum albumin(BSA)as a model protein,we evaluated the two systems and aimed to reduce the uncertainties of both the reactants and products in the corresponding kinetic study.In the laboratory simulation system,the generated gaseous pollutants showed negligible losses.Ten layers of BSA were coated on the flow tube with protein extraction recovery of 87.4%.For environmental exposure experiment,quartz fiber filter was selected as the upper filter with low gaseous O_(3)(8.0%)and NO_(2)(1.7%)losses,and cellulose acetate filter was appropriate for the lower filter with protein extraction efficiency of 95.2%.The protein degradation process was observed without the exposure to atmospheric oxidants and contributed to the loss of protein monomer mass fractions,while environmental factors(e.g.,molecular oxygen and ultraviolet)may cause greater protein monomer losses.Based on the evaluation,the study exemplarily applied the two systems to protein modification and both showed that O_(3) promotes the protein oligomerization and nitration,while increased temperature can accelerate the oligomerization and increased relative humidity can inhibit the nitration in the environmental exposure samples.The developed laboratory and environmental systems are suitable for studying protein modifications formed under different atmospheric conditions.A combination of the two will further reveal the actual mechanism of protein modifications.

Laboratory simulation on acoustic well-logging with phased array transmitter

Two small scale acoustic phased arrays with 4 elements have been designed and assembled in the laboratory. Experiments have been carried out with them. It is found that both directivity and radiation lobe width of the phased array can be regulated by changing the time delay between the input signals on neighboring elements. Results measured are in good agreement with those calculated. By using the phased array as an acoustic transmitter and hydrophone as a receiver, small scale acoustic well-logging simulations have been carried out both on an aluminum modei well and on a concrete one. Experimental results show that, by increasing the time delay of the input signals on neighboring elements, the steered radiation angle of the phased array becomes larger and larger, and generation conditions of the refracted compressional wave and the refracted shear wave are reached successively, and the refracted compressional wave, the refracted shear wave and the Stoneley wave are strengthened, respec-tively. Therefore, by choosing element spacing of a phased array and acoustic wave frequency appropriately, the main radiation lobe of the phased array can be widened to cover the first critical angle of all kinds of formations, which makes it possible to apply phased array acoustic well-logging in any formation continuously without regulating directivity of the phased array.

Surrogate atmospheric dust particles generated from dune soils in laboratory: Comparison with field measurement

Desert dust strongly influences the climate and the environment by altering the radiation budget, participating in atmospheric chemical reactions, and engaging the biogeochemical cycle. Studying its impacts requires knowledge of the physical and chemical properties of the original particles from the source origin. Unfortunately, the field collection of atmospheric samples in the desert is impractical. Fine surface soil is thus considered an alternative material from which to obtain the information applicable to dust particles from the desert soil. In this study, a laboratory system was set up to generate dust particles with simulated natural wind erosion processes from surface soils or directly from desert surfaces. Surface soils and field dust were simultaneously collected during a local blowing dust event. The comparison between the laboratory-generated dust and the field dust showed a consistent trend in particle size distribution and chemical composition. The chemical compositions were found to have explainable differences with the Certified Reference Materials for Asian dust (CJ-2). The laboratory-generated dust particles with the system could be applied as surrogates for soil-emitted dust in desert areas.

Laboratory simulation and CO_(2) flooding efficiency of oil-water transition zones in a low permeability reservoir in the Jilin Oilfield

Geological reserves of oil-water transition zone(OWTZ)in low-permeability reservoirs have been considered as uneconomical resources because of high water cut and low abundance.Though the OWTZ may account for 30%-50%of a reservoir,it has not been paid more attentions yet.The average oil saturation of the OWTZ is about 35%,which is equal to that of a reservoir after water flooding.Currently,CO_(2) flooding is an effective technique for residual oil recovery after water flooding,which could reduce the residual oil saturation greatly.Therefore,it is of significance for the EOR of the low-permeability reservoir if the CO_(2) flooding could be successfully applied in the OWTZ.In this study,a method based on a long core to simulate distribution of oil saturation in OWTZs is set up in the laboratory using bidirectional saturation.In order to investigate CO_(2) flooding characteristics in OWTZs,experiments are carried out on 3 sets of initial oil saturation,and the recoverable reserves of the OWTZ and its contribution to the EOR are calculated based on the WJ reservoir in the Jilin Oilfield,China.

In Situ Corrosion Monitoring of Mild Steel in a Simulated Tidal Zone without Marine Fouling Attachment by Electrochemical Impedance Spectroscopy

The corrosion behaviors of the isolated short and vertical long scale Q235B steel in a simulated tidal zone were studied by electrochemical impedance spectroscopy （EIS） monitoring and corrosion weight loss calculation in an experimental indoor simulating trough. The results show that the corrosion rate of the isolated short scale Q235B steel in the tidal zone acquired by the EIS agrees with the corrosion weight loss result. The corrosion rates of the short scale steel are in the order of middle tidal zone 〉 the central zone between the middle tidal zone and low tidal zone 〉 high tidal zone 〉 low tidal zone. The fastest corrosion rate in the middle tidal zone is attributed to the longest wet time in a tidal cycle. According to the comparison of corrosion weight loss between the vertical long scale and isolated short scale specimens, the corrosion rate of vertical long scale specimens of Q235B steel is lower than that of the isolated short scale specimens in the tidal zone, but the result is contrary in the immersion zone.

Effect of Cooling Rate on the Room Temperature Microstructure Following the Intercritical Deformation of Steel S460

The effect of final hot rolling in the intercritical (α+γ) region on microstructure and properties is very specific to the individual processing conditions and the chemical composition of a steel.S460 is a plate steel processed in this way.To reproduce at the laboratory scale,a multi-stage simulation was developed which included a high temperature austenite deformation and an isothermal hold.The effect of the applied cooling rate following intercritical deformation was investigated.At 1K/s (typical industrial cooling) the microstructure was similar to the reference sample,but included an intragranular ferrite fraction.This was due to differences in processing history,and considered to be linked to a larger prior austenite grain size.At an accelerated cooling rate (15K/s),acicular ferrite formed on shear bands within the strained austenite phase.EBSD scans have been completed to provide further information about the microstructures,with band contrast able to identify the pearlite phase at the slowest cooling rate.This is a starting point from which to focus on the ferrite morphologies.