Laboratory Experiments Do Not Support the Greenhouse Effect as Applicable to CO2

The analysis of Greenhouse Effect experiments in the public domain indicated that the lab tests were primarily centered around illustrating the mechanics of conventional greenhouses. They used high-energy visible light (such as sunlight), rather than addressing the Greenhouse Effect, which involves low-energy infrared radiation emitted by the Earth’s surface. Studies with argon, a non-greenhouse gas with similar density to CO2, showed thermal heat transfer as the dominant factor in the temperature profiles, with radiation absorption being undetected. The same conclusion was drawn by another study, which measured infrared back radiation. Experiments using exaggerated CO2 concentrations inadvertently illustrated the principle of the Popper Falsification Test by disproving the Greenhouse Effect applicable to CO2 within the troposphere. A straightforward kitchen test showed that a microwave oven cannot be used as a model for the Greenhouse Effect.

A laboratory acoustic emission experiment and numerical simulation of rock fracture driven by a high-pressure fluid source

In order to improve our understanding of rock fracture and fault instability driven by high-pressure fluid sources, the authors carried out rock fracture tests using granite under a confining pressure of 80 MPa with fluid injection in the laboratory. Furthermore, we tested a number of numerical models using the FLAC;modeling software to find the best model to represent the experimental results. The high-speed multichannel acoustic emission（AE） waveform recording system used in this study made it possible to examine the total fracture process through detailed monitoring of AE hypocenters and seismic velocity.The experimental results show that injecting high-pressure oil into the rock sample can induce AE activity at very low stress levels and can dramatically reduce the strength of the rock. The results of the numerical simulations show that major experimental results, including the strength, the temporal and spatial patterns of the AE events, and the role of the fluid can be represented fairly well by a model involving（1） randomly distributed defect elements to model pre-existing cracks,（2） random modification of rock properties to represent inhomogeneity introduced by different mineral grains, and（3）macroscopic inhomogeneity. Our study, which incorporates laboratory experiments and numerical simulations, indicates that such an approach is helpful in finding a better model not only for simulating experimental results but also for upscaling purposes.

Comparing the reinforcement capacity of welded steel mesh and a thin spray-on liner using large scale laboratory tests

Steel mesh is used as a passive skin confinement medium to supplement the active support provided by rock bolts for roof and rib control in underground coal mines. Thin spray-on liners(TSL) are believed to have the potential to take the place of steel mesh as the skin confinement medium in underground mines.To confirm this belief, large scale laboratory experiments were conducted to compare the behaviour of welded steel mesh and a TSL, when used in conjunction with rock bolts, in reinforcing strata with weak bedding planes and strata prone to guttering, two common rock conditions which exist in coal mines. It was found that while the peak load taken by the simulated rock mass with weak bedding planes acting as the control sample(no skin confinement) was 2494 kN, the corresponding value of the sample with 5 mm thick TSL reinforcement reached 2856 kN. The peak load of the steel mesh reinforced sample was only2321 kN, but this was attributed to the fact that one of the rock bolts broke during the test. The TSL reinforced sample had a similar post-yield behaviour as the steel mesh reinforced one. The results of the large scale guttering test indicated that a TSL is better than steel mesh in restricting rock movement and thus inhibiting the formation of gutters in the roof.

Laboratory Observations on Internal Solitary Wave Evolution over A Submarine Ridge

Laboratory experiments were conducted in a wave flume on internal solitary wave （ISW） of depression and elevation types propagating over a submarine ridge in semicircular/triangular shape. Tests were arranged in series for combinations of submarine ridges of different heights and ISW of different amplitudes. The resuhant wave motions were found differing from thee of surface gravity waves. In deeper water, where an ISW of depression-type prevailed, the process of wave breaking displayed downward motion with continuous eddy on the front face of the ridge followed by upward motion towards the apex of the obstacle. Experimental results also suggested that blockage parameter ξ could be applied to classify various degrees of ISW-ridge interaction, i.e., ξ 〈 0.5 for weak interaction, 0.5 〈 ξ 〈 0.7 for moderate interaction, and 0.7 〈 ξ for wave breaking.

3D Mobile Augmented Reality Interface for Laboratory Experiments

In fields such as science and engineering, virtual environment is commonly used to provide replacements for practical hands-on laboratories. Sometimes, these environments take the form of a remote interface to the physical laboratory apparatus and at other times, in the form of a complete software implementation that simulates the laboratory apparatus. In this paper, we report on the use of a semi-immersive 3D mobile Augmented Reality (mAR) interface and limited simulations as a replacement for practical hands-on laboratories in science and engineering. The 3D-mAR based interfaces implementations for three different experiments (from micro-electronics, power and communications engineering) are presented;the discovered limitations are discussed along with the results of an evaluation by science and engineering students from two different institutions and plans for future work.

Study on Load Bearing Characteristics of Novel Expandable Deepwater Drilling Conductor Based on Laboratory Experiment and Field Test

A novel expandable conductor was designed and applied in deep-water drilling to improve the vertical and lateral bearing capacity with a significant reduction of conductor jetting depth and soaking time. The vertical and lateral bearing capability of expandable conductors was depicted based on the ultimate subgrade reaction method and pile foundation bearing theory. The load-bearing characteristics of a laboratory-scale expandable conductor were analyzed through laboratory experiments. The serial simulation experiments are accomplished to study the bearing characteristics(vertical ultimate bearing capacity, lateral soil pressure, and lateral displacement) during the conductor soaking process. The laboratory experimental results show that the larger the length and thickness of expandable materials are,the higher the bearing capacity of the wellhead will be. During the conductor soaking process, the soil pressure around the three expandable conductors increases faster, strings representing a stronger squeezing effect and resulting in higher vertical bearing capacity. Furthermore, the lateral displacement of novel expandable conductor is smaller than that of the conventional conductor. All the advantages mentioned above contributed to the reduction of conductor’s jetting depth and soaking time. Lastly, the application workflow of a novel expandable deep-water drilling conductor was established and the autonomous expandable conductor was successfully applied in the South China Sea with a significant reduction of conductor’s jetting depth and soaking time. According to the soil properties and designed installation depth of the surface conductor, the arrangement of expandable materials should be designed reasonably to meet the safety condition and reduce the construction cost of the subsea wellhead.

Numerical modeling of zero-offset laboratory data in a strong topographic environment: results for a spectral-element method and a discretized Kirchhoff integral method

Abstract Accurate simulation of seismic wave propaga- tion in complex geological structures is of particular interest nowadays. However conventional methods may fail to simulate realistic wavefields in environments with great and rapid structural changes, due for instance to the presence of shadow zones, diffractions and/or edge effects. Different methods, developed to improve seismic model- ing, are typically tested on synthetic configurations against analytical solutions for simple canonical problems or ref- erence methods, or via direct comparison with real data acquired in situ. Such approaches have limitations,especially if the propagation occurs in a complex envi- ronment with strong-contrast reflectors and surface irreg- ularities, as it can be difficult to determine the method which gives the best approximation of the ＂real＂ solution, or to interpret the results obtained without an a priori knowledge of the geologic environment. An alternative approach for seismics consists in comparing the synthetic data with high-quality data collected in laboratory experi- ments under controlled conditions for a known configuration. In contrast with numerical experiments, laboratory data possess many of the characteristics of field data, as real waves propagate through models with no numerical approximations. We thus present a comparison of laboratory-scaled measurements of 3D zero-offset wave reflection of broadband pulses from a strong topographic environment immersed in a water tank with numerical data simulated by means of a spectral-element method and a discretized Kirchhoff integral method. The results indicate a good quantitative fit in terms of time arrivals and acceptable fit in amplitudes for all datasets.

A new elastoplastic model for bolt-grouted fractured rock

Complexities in mechanical behaviours of rock masses mainly stem from inherent discontinuities,which calls for advanced bolt-grouting techniques for stability enhancement.Understanding the mechanical properties of bolt-grouted fractured rock mass(BGFR)and developing accurate prediction methods are crucial to optimize the BGFR support strategies.This paper establishes a new elastoplastic(E-P)model based on the orthotropic and the Mohr-Coulomb(M-C)plastic-yielding criteria.The elastic parameters of the model were derived through a meso-mechanical analysis of composite materials mechanics(CMM).Laboratory BGFR specimens were prepared and uniaxial compression test and variable-angle shear test considering different bolt arrangements were carried out to obtain the mechanical parameters of the specimens.Results showed that the anisotropy of BGFR mainly depends on the relative volume content of each component material in a certain direction.Moreover,the mechanical parameters deduced from the theory of composite materials which consider the short fibre effect are shown to be in good agreement with those determined by laboratory experiments,and the variation rules maintained good consistency.Last,a case study of a real tunnel project is provided to highlight the effectiveness,validity and robustness of the developed E-P model in prediction of stresses and deformations.

Shale oil recovery by CO_(2)injection in Jiyang Depression,Bohai Bay Basin,East China

Laboratory experiments,numerical simulations and fracturing technology were combined to address the problems in shale oil recovery by CO_(2)injection.The laboratory experiments were conducted to investigate the displacement mechanisms of shale oil extraction by CO_(2)injection,and the influences of CO_(2)pre-pad on shale mechanical properties.Numerical simulations were performed about influences of CO_(2)pre-pad fracturing and puff-n-huff for energy replenishment on the recovery efficiency.The findings obtained were applied to the field tests of CO_(2)pre-pad fracturing and single well puff-n-huff.The results show that the efficiency of CO_(2)puff-n-huff is affected by micro-and nano-scale effect,kerogen,adsorbed oil and so on,and a longer soaking time in a reasonable range leads to a higher exploitation degree of shale oil.In the"injection+soaking"stage,the exploitation degree of heavy hydrocarbons is enhanced by CO_(2)through its effects of solubility-diffusion and mass-transfer.In the"huff"stage,crude oil in large pores is displaced by CO_(2)to surrounding larger pores or bedding fractures and finally flows to the production well.The injection of CO_(2)pre-pad is conducive to keeping the rock brittle and reducing the fracture breakdown pressure,and the CO_(2)is liable to filter along the bedding surface,thereby creating a more complex fracture.Increasing the volume of CO_(2)pre-pad can improve the energizing effect,and enhance the replenishment of formation energy.Moreover,the oil recovery is more enhanced by CO_(2)huff-n-puff with the lower shale matrix permeability,the lower formation pressure,and the larger heavy hydrocarbon content.The field tests demonstrate a good performance with the pressure maintained well after CO_(2)pre-pad fracturing,the formation energy replenished effectively after CO_(2)huff-n-puff in a single well,and the well productivity improved.

Rotating tank experiments for the study of geophysical fluid dynamics

Geophysical fluid dynamics(GFD)is an interdisciplinary field that studies the large-scale motion of fluids in the natural world.With a wide range of applications such as weather forecasts and climate prediction,GFD employs various research approaches including in-situ observations,satellite measurements,numerical simulations,theoretical analysis,artificial intelligence,and physical model experiments in laboratory.Among these approaches,rotating tank experiments provide a valuable tool for simulating naturally-occurring fluid motions in laboratories.With proportional scaling and proper techniques,scientists can reproduce multi-scale physical processes of stratified fluids in the rotation system,which allows for the simulation of essential characteristics of fluid motions in the atmosphere and oceans.In this review,rotating tanks of various scales in the world are introduced,as these tanks have been actively used to explore fundamental scientific questions in ocean and atmosphere dynamics.To illustrate the GFD experiments,three representative cases are presented to demonstrate the frontier achievements in the the GFD study by using rotating tank experiments:mesoscale eddies in the ocean,convection processes,and plume dynamics.Detailed references for the experimental procedures are provided.Future studies are encouraged to further explore the utilization of rotating tanks with improvements in experimental design and integration of other research methods.This is a promising direction of GFD to help enhance our understanding of the complex nature of fluid motions in the natural world and to address the challenges posed by global environmental changes.

Screening and field application of microbial-flooding activator systems

This study aims to further enhance the oil recovery of reservoirs in the Zhong-2 Block of the Gudao Oilfield by identifying the most effective microbial-flooding activator systems and applying them in the field.We began by analyzing the structure of the reservoirs'endogenous microbial communities to understand the potential impact of microbial flooding.This was followed by determining commonly used activator systems based on their abilities to stimulate oil-displacement functional bacteria.Through laboratory experiments on oil displacement efficiency and sweep characteristics,we determined the optimal activator injection method(injection ratio)and the requisite bacterial concentration for maximal microbial-flooding efficacy.Finally,we selected the optimal activator systems and applied them to field tests.Our findings suggest the target block is highly receptive to microbial-flooding.In terms of performance,the activator systems ranked as No.3>No.4>No.1>No.2.Interestingly,a deep activator system,when compared to the top-performing No.3 system,exhibited a higher bacterial concentration peak and longer peaking duration.Optimal oil displacement effects were observed at a 1:4 vol ratio between the No.3 activator and deep activator systems,with bacterial concentrations of up to 106 cells/mL or above.Field tests with the selected activator systems,following a specific injection protocol,demonstrated a notable increase in oil production and a reduction in water cut.

Redox mechanism of geobattery and related electrical signals using a novel real-time self-potential monitoring experimental platform

Controlled laboratory experiments are proved to be a valuable tool for investigating changes in underground physical properties and the related response of surface geophysical signals.The self-potential(SP)method is widely used in mineral resource exploration due to its direct correlation with underground electrochemical gradients.This paper presented the design and construction of an experimental platform based on a multi-channel SP monitoring system.The proposed platform was used to monitor the anodizing corrosion process of different metal blocks from a laboratory perspective,record the real-time SP signal generated by the redox reaction,as well as investigate the geobattery mechanism associated with the natural polarization process of metal mineral resources.The experimental results demonstrate that the constructed SP monitoring platform effectively captures time-series SP signals and provides direct laboratory evidence for the geobattery model.The measured SP data were quantitatively interpreted using the simulated annealing algorithm,and the inversion results closely match the real model.This finding highlights the potential of the SP method as a promising tool for determining the location and spatial distribution of underground polarizers.The study holds reference value for the exploration and exploitation of mineral resources in both terrestrial and marine environments.

Design of A Hydraulic Power Take-off System for the Wave Energy Device with An Inverse Pendulum

This paper describes a dual-stroke acting hydraulic power take-off （PTO） system employed in the wave energy converter （WEC） with an inverse pendulum. The hydraulic PTO converts slow irregular reciprocating wave motions to relatively smooth, fast rotation of an electrical generator. The design of the hydraulic PTO system and its control are critical to maximize the generated power. A time domain simulation study and the laboratory experiment of the full-scale beach test are presented. The results of the simulation and laboratory experiments including their comparison at full-scale are also presented, which have validated the rationality of the design and the reliability of some key components of the prototype of the WEC with an inverse pendulum with the dual-stroke acting hydraulic PTO system.

Mechanical behaviour analysis and support system field experiment of confined concrete arches

Soft rock control is a big challenge in underground engineering.As for this problem,a high-strength support technique of confined concrete(CC)arches is proposed and studied in this paper.Based on full-scale mechanical test system of arch,research is made on the failure mechanism and mechanical properties of CC arch.Then,a mechanical calculation model of circular section is established for the arches with arbitrary section and unequal rigidity;a calculation formula is deduced for the internal force of the arch;an analysis is made on the influence of different factors on the internal force of the arch;and a calculation formula is got for the bearing capacity of CC arch through the strength criterion of bearing capacity.With numerical calculation and laboratory experiment,the ultimate bearing capacity and internal force distribution is analyzed for CC arches.The research results show that:1)CC arch is 2.31 times higher in strength than the U-shaped steel arch and has better stability;2)The key damage position of the arch is the two sides;3)Theoretical analysis,numerical calculation and laboratory experiment have good consistency in the internal force distribution,bearing capacity,and deformation and failure modes of the arch.All of that verifies the correctness of the theoretical calculation.Based on the above results,a field experiment is carried out in Liangjia Mine.Compared with the U-shaped steel arch support,CC arch support is more effective in surrounding rock deformation control.The research results can provide a basis for the design of CC arch support in underground engineering.

高压输电线路雷击闪络的实验室研究(英文)

This paper presents an investigation on the attractive width of high voltage transmission lines to lightning strikes.In order to design the optimal lightning protection,the estimated number of lightning flashes on the line, which is based on its attractive width,needs to be determined.The investigation was performed using experiments with model tests at the Mississippi State University High Voltage Laboratory.For laboratory experiments,a total of 2,100 negative and positive switching impulse voltages were applied to transmission line models from a conducting rod,which represented a lightning downward leader.Different tested models of transmission lines on a scale of 1:100 were used.The effects of overhead ground wires,phase conductors,tower structures,and the magnitude and polarity of lightning strokes were also studied.The attractive width increased gradually with the height of overhead ground wires and towers as well as the magnitude of the lightning stroke current.Impulse polarity had an impact on the attractive width,and the attractive width for negative polarity was larger than that for positive polarity.The taller tower had more effect on flash distribution to transmission lines than the shorter one.The experimental results agree with the actual transmission line observations published in literature.The new expressions for the attractive width of transmission lines,based on the experimental results,were established.The accurate estimation of the attractive width can help electric power utilities plan transmission systems reliably and economically.The detailed description of the background problem,proposed method,experimental results,and analysis are presented in this paper.

Pyrite-hydrocarbon Interaction under Hydrothermal Conditions: an Alternative Origin of H_2S and Organic Sulfur Compounds in Sedimentary Environments

Sulfate rocks and organic sulfur from sedimentary organic matter are conventionally assumed as the original sulfur sources for hydrogen sulfide （H2S） in oil and gas reservoirs. However, a few recent experiments preliminarily indicate that the association of pyrite and hydrocarbons may also have implications for H2S generation, in which water effects and natural controls on the evolution of pyrite sulfur into OSCs and H2S have not been evaluated. In this study, laboratory experiments were conducted from 200 to 450°C to investigate chemical interactions between pyrite and hydrocarbons under hydrothermal conditions. Based on the experimental results, preliminary mechanism and geochemical implications were tentatively discussed. Results of the experiments showed that decomposition of pyrite produced H2S and thiophenes at as low as 330°C in the presence of water and n-pentane. High concentrations of H2S were generated above 450°C under closed pyrolysis conditions no matter whether there is water in the designed experiments. However, much more organic sulfur compounds （OSCs） were formed in the hydrous pyrolysis than in anhydrous pyrolysis. Generally, most of sulfur liberated from pyrite at elevated temperatures was converted to H2S. Water was beneficial to breakdown of pyrite and to decomposition of alkanes into olefins but not essential to formation of large amounts of H2S, given the main hydrogen source derived from hydrocarbons. In addition, cracking of pyrite in the presence of 1-octene under hydrous conditions was found to proceed at 200°C, producing thiols and alkyl sulfides. Unsaturated hydrocarbons would be more reactive intermediates involved in the breakdown of pyrite than alkanes. The geochemistry of OSCs is actually controlled by various geochemical factors such as thermal maturity and the carbon chain length of the alkanes. This study indicates that the scale of H2S gas generated in deep buried carbonate reservoirs via interactions between pyrite and natural gas should be much smaller than that of thermochemical sulfate reduction （TSR） due to the scarcity of pyrite in carbonate reservoirs and the limited amount of long-chained hydrocarbons in natural gas. Nevertheless, in some cases, OSCs and/or low contents of H2S found in deep buried reservoirs may be associated with the deposited pyrite-bearing rock and organic matters （hydrocarbons）, which still needs further investigation.

Water migration in subgrade soil under seasonal freeze-thaw cycles in an alpine meadow on the Qinghai-Tibet Plateau

Highway frost heave and thawing settlement caused by water migration towards the freezing front and ice lens development is widespread in the alpine meadow area of the southeast QinghaiTibet Plateau(QTP). A laboratory experiment on a highway reconstruction and expansion project in the QTP was carried out in this work to analyze the effects of fine particle content, initial water content, and the number of freeze-thaw cycles(FTCs) on frost depth, temperature gradient(Grad T), total water intake, and water intake flux. Based on the results of the laboratory experiment, a modified model of migration potential related to fine particle content, freeze-thaw history, and freezing time was established. The results show that, with the increase of fine particle content, the frost depth of soil decreases, the curve of total water intake over time is transformed from an Sshape to an arch, and the curve of water intake flux over time is transformed from a peak shape to descending shape. The variation trend of migration potential with freezing time and the freeze-thaw history is the same as that of water intake flux with freezing time and freeze-thaw history. The variation trend of soil intake flux can be used as a reference to determine the variation trend of soil migration potential. This study provides a reference for the design and construction of highway subgrade in the alpine meadow area of the QTP.

Experimental Research on Wave Transmission over Submerged Rubble-Mound Breakwaters

This paper discusses some previous, and presents some new experimental results on wave transmission over submerged breakwaters. The objective of this study is to evaluate wave transmission coefficient and develop a two-dimensional （2D） model as an improvement to the existing wave transmission coefficient models. Factors which affect wave transmission over stbmerged breakwaters are discussed through a series of laboratory experiments. Basic recommendations for evaluation and design of submerged rubble-monud breakwaters are presented. From the test results, a calculation formula of wave transmission coefficient is proposed.

Experimental investigation and flow analysis of clear-water scour around pier and abutment in proximity

Local scour around bridge piers and abutments is one of the most significant causes of bridge failure.Despite a plethora of studies on scour around individual bridge piers or abutments,few studies have focused on the joint impact of a pier and an abutment in proximity to one another on scour.This study conducted laboratory experiments and flow analyses to examine the interaction of piers and abutments and their effect on clear-water scour.The experiments were conducted in a rectangular laboratory flume.They included 18 main tests(with a combination of different types of piers and abutments)and five control tests(with individual piers or abutments).Three pier types(a rectangular pier with a rounded edge,a group of three cylindrical piers,and a single cylindrical pier)and two abutment types(a wingewall abutment and a semicircular abutment)were used.An acoustic Doppler velocimeter was used to measure the three-dimensional flow velocity for analyses of streamline,velocity magnitude,vertical velocity,and bed shear stress.The results showed that the velocity near the pier and abutment increased by up to 80%.The maximum scour depth around the abutment increased by up to 19%.In contrast,the maximum scour depth around the pier increased significantly by up to l71%.The presence of the pier in the vicinity of the abutment led to an increase in the scour hole volume by up to 87%relative to the case with a solitary abutment.Empirical equations were also derived to accurately estimate the maximum scour depth at the pier adjacent to the abutment.

An Experimental Study on the Pressure Distribution in Horizontal Gas Wells

Laboratory experiments have been carried out to study the fluid flow in the wellbore of a horizontal gas well during the production process.The related pressure distribution has been determined considering different cases(different inflow media,different perforation opening methods and different liquid holdup).It has been found that the larger the fluid flow rate,the greater the pressure changes in the wellbore under the same hole opening mode.The uniformity of the perforation opening method was also an important factor affecting the magnitude of the wellbore pressure change.The liquid holdup also affected the pressure distribution,especially when the gas volumetric flow rate exceeded 200 m3/h.Comparison of the outcomes of the present experimental study with the predictions of a theoretical model available in the literature has provided a relative error smaller than 20%.