Recent Study of Drag Embedment Plate Anchors in China

Experimental and theoretical studies of drag embedment plate anchors recently carried out in Tianjin University are summarized in this research paper, which involve a series of important topics relevant to the study of drag anchors. The techniques for measuring the trajectory and movement direction of drag anchors in soils, the techniques for measuring the moving embedment point and reverse eatenary shape of the embedded drag line, the penetration mechanism and kinematic behavior of drag anchors, the ultimate embedment depth of drag anchors, the movement direction of the anchor with an arbitrary fluke section, the reverse catenary properties of the embedded drag line, the interaetional properties between drag anchor and installation line, the kinematic model of drag anchors in seabed soils, and the analytical method for predicting the anchor trajectory in soils will all be examined. The present work remarkably reduces the uncertainties in design and analysis of drag embedment plate anchors, and is beneficial to improving the application of this new type of drag anchor in offshore engineering.

Critical embedment depth of a rigid retaining wall against overturning in unsaturated soils considering intermediate principal stress and strength nonlinearity

The overturning stability is vital for the retaining wall design of foundation pits, where the surrounding soils are usually unsaturated due to water draining. Moreover, the intermediate principal stress does affect the unsaturated soil strength; meanwhile, the relationship between the unsaturated soil strength and matric suction is nonlinear. This work is to present closed-form equations of critical embedment depth for a rigid retaining wall against overturning by means of moment equilibrium. Matric suction is considered to be distributed uniformly and linearly with depth. The unified shear strength formulation for unsaturated soils under the plane strain condition is adopted to characterize the intermediate principal stress effect, and strength nonlinearity is described by a hyperbolic model of suction angle. The result obtained is orderly series solutions rather than one specific answer; thus, it has wide theoretical significance and good applicability. The validity of this present work is demonstrated by comparing it with a lower bound solution. The traditional overturning designs for rigid retaining walls, in which the saturated soil mechanics neglecting matric suction or the unsaturated soil mechanics based on the Mohr-Coulomb criterion are employed, are special cases of the proposed result. Parametric studies about the intermediate principal stress, matric suction and its distributions along with two strength nonlinearity methods on a new defined critical buried coefficient are discussed.

Characterization of the fracture compressibility and its permeability for shale under the effects of proppant embedment and compaction:A preliminary study

Hydraulic fracturing technology plays a key role in improving the recovery rate of shale gas.The improvement of permeability in relation to hydraulic fracturing depends on changes brought about by the proppant on the fracture structure in reservoirs.Then it is of great significance to describe the microscopic changes during this process by means of an accurate theoretical model.In this study,based on the heterogeneity of shale fracture and the compaction and embedment of a proppant,we proposed a permeability model to examine the combined effects of a proppant and stress to describe the change mechanism in permeability.Further,changes in fracture width and porosity were considered,and a calculation model of fracture compressibility under proppant compaction and embedment was proposed.The difference from previous studies is that the compressibility and permeability of supported fractures can be further quantified and analyzed by this model.Moreover,its rationality was verified by publicly released test data.The results show that,the compressive effect of stress and the embedding of proppant both have a negative impact on shale permeability.

Crushing and embedment of proppant packs under cyclic loading: An insight to enhanced unconventional oil/gas recovery

Crushing and embedment are two critical downhole proppant degradation mechanisms that lead to a significant drop in production outputs in unconventional oil/gas stimulation projects. These persistent production drops due to the non-linear responses of proppants under reservoir conditions put the future utilization of such advanced stimulation techniques in unconventional energy extraction in doubt. The aim of this study is to address these issues by conducting a comprehensive experimental approach. According to the results, whatever the type of proppant, all proppant packs tend to undergo significant plastic deformation under the first loading cycle.Moreover, the utilization of ceramic proppants(which retain proppant pack porosity up to 75%), larger proppant sizes(which retain proppant pack porosity up to 15.2%) and higher proppant concentrations(which retain proppant pack porosity up to 29.5%) in the fracturing stimulations with higher in-situ stresses are recommended to de-escalate the critical consequences of crushing associated issues. Similarly, the selection of resin-coated proppants over ceramic and sand proppants may benefit in terms of obtaining reduced proppant embedment.In addition, selection of smaller proppant sizes and higher proppant concentrations are suggested for stimulation projects at depth with sedimentary formations and lower in-situ stresses where proppant embedment predominates. Furthermore, correlation between proppant embedment with repetitive loading cycles was studied.Importantly, microstructural analysis of the proppant-embedded siltstone rock samples revealed that the initiation of secondary induced fractures. Finally, the findings of this study can greatly contribute to accurately select optimum proppant properties(proppant type, size and concentration) depending on the oil/gas reservoir characteristics to minimize proppant crushing and embedment effects.

Upper bound seismic rotational stability analysis of gravity retaining walls considering embedment depth

Stability analysis of gravity retaining wall was currently based on the assumption that the wall had no embedment depth. The effect of earth berm was usually neglected. The present work highlighted the importance of embedment depth when assessing the seismic stability of gravity retaining walls with the pattern of pure rotation. In the framework of upper bound theorem of limit analysis, pseudo-static method was applied into two groups of parallel rigid soil slices methods in order to account for the effect of embedment depth on evaluating the critical acceleration of wall-soil system. The present analytical solution is identical to the results obtained from using limit equilibrium method, and the two methods are based on different theory backgrounds. Parameter analysis indicates that the critical acceleration increases slowly when the ratio of the embedment depth to the total height of the wall is from 0 to 0.15 and increases drastically when the ratio exceeds 0.15.

Structural Research on Embedment of a Bare Deflated Spiral Case

Complete bearing spiral case has not been applied to large power stations in China so far. The proposal of applying complete bearing spiral case necessitates an analysis of the reliability of the spiral case structure and the security of units under various working conditions. In combination with practice of a project, this paper presents a three-dimensional nonlinear finite element static analysis of the concrete using a concrete smeared crack model by means of the well-known finite element method （FEM） software ABAQUS. The stress distribution of the spiral case and reinforcing bars, the range of damages in surrounding concrete, and the displacement of structure are quantified. The computational results indicate that the embedment method ensures the structure＇s safety in strength. At the same time, the result shows that this embedment is a kind of preponderant method for embedment in aspects of economy and technique of construction, and the application of this embedment method to the hydropower station is feasible provided that some proper engineering measures are taken to constrain the width of the concrete in accord with the code＇s requirements. The paper proves the security and reliability of the structural design of spiral case in hydropower station accordingly.

Computation model of proppant embedment depth based on dimensional analysis

Hydraulic fracturing is designed to form a high-conductivity fracture. The proppant will embed into the formation rock, especially in soft rock, owing to the interaction between proppant and fracture surface after fracture closure. Proppant embedment would reduce the fracture width and then lower the fracture conductivity. According to dimensional analysis, the rock is assumed to be an elastic material. Using the theory of elasticity to describe the stage of elastic deformation and analysis of the corresponding simplified embedding process, the study establish the static computation model of the two-dimensional infinite half plane and three-dimensional infinite half space model of the proppant embedment. According to laboratory results, the calculation model was modified, got an effective correction factor and analyzed the causes of errors, then discussed the factors which have impact on proppant embedment. The result calculated by the model in this paper can be reference of prop- pant optimization in on-site fracturing for a certainty degree.

Techno-ethics Embedment： A New Trend in Technology Assessment

Facing the ethical potentials of technology, there appears a new trend in technology assessment （TA） recently, which is techno-ethics embedment that aims embed ethical perspectives within the process of assessing and developing new technologies. There are two basic dimensions of this trend： the role of ethics and the status of technology. By referring these dimensions, I articulate two different TA modes of the techno-ethics embedment： One is the ethical technology assessment （eTA） that appears as a combination of an ethical judge with the objective technological force, while the other is the combination of an engaged ethical participant with an active technological mediator. Moreover, there is an ideal status of this trend that is an engaged ethical participant with an active technological mediator. As the thought of technology accompaniment shows, both the ＂agency＂ of human and technology will be embodied to the most in this ideal status of techno-ethics embedment.

Calculation method of proppant embedment depth in hydraulic fracturing

For the issue of proppant embedment in hydraulic fracturing,a new calculation method of embedment depth considering elastic-plastic deformation was proposed based on the mechanism of proppant embedment into rocks by combining proppant embedment constitutive equations and contact stresses on the rock-proppant system.And factors affecting embedment depth of proppant were analyzed using the new method.Compared with the elastic embedment model,the results calculated by the new method match well with the experimental data,proving the new method is more reliable and more convenient to make theoretical calculation and analysis.The simulation results show the process of proppant embedment into rocks is mainly elastic-plastic.The embedment depth of monolayer proppants decreases with higher proppant concentration.Under multi-layer distribution conditions,increasing the proppant concentration will not change its embedment depth.The larger the proppant embedment ratio,the more the stress-bearing proppants,and the smaller the embedment depth will be.The embedment depth under higher closure stress is more remarkable.The embedment depth increased with the drawdown of fluid pressure in the fracture.Increasing proppant radius or the ratio of proppant Young’s modulus to rock Young’s modulus can reduce the proppant embedment depth.

Morphological features of allogenic nerve segment in rats after subcutaneous embedment

BACKGROUND ： Some studies demonstrate that allogenic peripheral nerve segment embedded subcutaneously significantly reduce the infiltration of lymphocyte and decrease immunological reaction.OBJECTIVE ： To observe the gross shape, optical and electron microscope results of allogenic nerve segment in rats 2 weeks after subcutaneous embedment, and compare with subcutaneous emdedment of autologous nerve segment. DESIGN ： A randomized and controlled experiment.SETTING ： Department of Orthopaedics of Fifth People＇s Hospital of Zhengzhou; Department of Orthopaedics,First Hospital Affiliated to Chongqing Medical University.MATERIALS ： Totally 30 adult healthy Wistar male rats, with body mass of （200±20） g, were enrolled. Ten rats were chosen as the donors of allogenic nerve transplantation. The other 20 rats were randomly divided into 2 groups： allogenic nerve embedment group and autologous nerve embedment group, with 10 rats in each one. JEM-1220 transmission electron microscope （Japan） and Olympus BX50 optical microscope （Japan） were used. METHODS ： This experiment was carried out at the laboratory of Orthopaedic Department, Chongqing Medical University from October 2000 to April 2002. ① Sciatic nerve of donor rats for allogenic nerve transplantation was cut off at 5 mm distant from pelvic strait.15 mm sciatic nerve segment was chosen from lateral part as graft, allogenic nerve embedment group： 15 mm sciatic nerve form the donor rats was embedded in the posterior part of right legs. Autologous nerve embedment group： 15 mm sciatic nerve segment of autologous left side was embedded in the posterior side of right legs. ② Nerve segment embedded subcutaneously was taken out at postoperative 2 weeks and performed gross observation; then 5 samples chosen randomly respectively from 2 groups and given haematoxylin-eosin staining and observation under optical microscope （×400）;The other 5 samples were made into ultrathin sections （0.5μm）and observed under transmission electron microscope（×17 000）. MAIN OUTCOME MEASURES ： Gross shape, optical and electron microscope results of nerve segments of rats between two groups at 2 weeks after subcutaneous embedment. RESULTS ： ① Results of gross observation： Appearance of nerve segment was similar between 2 groups. ② Results of optical observation： medullary sheath denaturation, axonotmesis, vascular engorgement, desmoplasia of adventitia and infiltration of inflammatory cells were all found in both 2 groups. Inflammatory reaction was a little more severe in the allogenic nerve embedment group than in the autologous nerve embedment groups.③Results of electron microscope ： Similar cataplasia and denaturation of medullary sheath and cataplasia of Schwann cell were all found in the 2 groups. CONCLUSION： Some inflammatory reaction occurs after allogenic nerve embedment, but the activity of Schwann cell is similar to that of peripheral nerve after autologous nerve embedment.

Embedment Effect on Eliminating Damage of CFRP Pull-riveting Process by Simulation Study

The rivet joints have been widely applied in aerospace and vehicle fields.During the joining process of the carbon fiber reinforced plastic(CFRP)laminates,the pre-tightening force of pulling-rivet was the key factor to ensure the connection performance.To predict the impact of clamping loads on stress and failure of laminates,the value of stress and damage evolution of the wall of a hole under the pre-tightening force were simulated by the finite element method.The results of the simulation showed that excessive clamping force led to the damage and failure of CFRP in the hole edge.Connection performance together with progressive failure process and failure modes of CFRP laminates with various pre-tightening forces were investigated.A kind of metal embedded parts embedded in the laminates was designed to reduce the damage by the simulation study.Simulation results showed that embedment reduced the failure and damage efficiently.The embedment reduced about 64%of the maximum stress.

On Some Embedment of Groups into Wreath Products

In this paper, we showed how groups are embedded into wreath products, we gave a simpler proof of the theorem by Audu (1991) (see [1]), also proved that a group can be embedded into the wreath product of a factor group by a normal subgroup and also proved that a factor group can be embedded inside a wreath product and the wreath product of a factor group by a factor group can be embedded into a group. We further showed that when the abstract group in the Universal Embedding Theorem is a p-group, cyclic and simple, the embedding becomes an isomorphism. Examples were given to justify the results.

Clinical efficacy of catgut embedment combined with moxibustion and bloodletting in the treatment of androgenic alopecia

Objective To observe the clinical efficacy of catgut embedment combined with moxibustion and bloodletting in the treatment of androgenic alopecia and to probe into its therapeutic mechanism. Methods Eighty-four patients with androgenic alopecia were divided into catgut embedment group （group A） and western medicine group （group B） on the basis of random number table and according to the order of treatment. For the pateints in group A, Shenguan （肾关） on both sides, Minghuang （明黄） and Zusanli （足三里 ST 36） were selected to receive catgut embedment therapy, once every month, combined with moxibustion on the lower abdomen and local bloodletting treatment. For the patients in group B, finasteride 1mg/d was orally administrated. The treatment period for two groups was 3 months, and the follow-up visit lasted for 3 months. Serum testosterone （T） and estradiol （E2） contents were detected respectively before treatment, after i month and 3 months of treatment and after 3 months of follow-up visit, and the specific values were calculated to make statistical analysis of T, E2, T/E2 and curative effects of the two groups after i month and 3 months of treatment and after 3 months of follow-up visit. Results There was no statistical significance in curative effect between the two groups after i month of treatment （P〉0.05）, and the curative effect in group A were better than that in group B after 3 months of treatment or after 3 months of follow-up visit （both P〈0.05）; E2 level in group A was lower than that in group A after 3 months of treatment （P〈0.05）; T, E2 and T/E2 in group A were all lower than that in group B after 3 month of follow-up visit （all P〈0.05）. Conclusion The curative effect of treating androgenic alopecia with catgut embedment, moxibustion and bloodletting is definite, and its mechanism of action may be related to the reduction of T levels and T/E2 values.

Decomposition and embedment of trajectories after explosion for a birth and death process

Let X = X(t),t < σ (σ is lifespan) be a birth and death process with explosion whose characteristic triple is (α, C, D). For a set $\bar M \subset \bar E = \left\{ {0, 1, 2, \cdots , \infty } \right\}$ , reserving the trajectories before the first explosion time τ and decomposing the trajectories after τ for X according to $\bar M$ we obtain a new birth and death process $_{\bar M} X = \left\{ {_{\bar M} X\left( t \right), t < _{\bar M} \tau } \right\}$ . We calculate the average lifetime after τ for $_{\bar M} X$ and corresponding characteristic triple $\left( {_{\bar M} \alpha , _{\bar M} C, _{\bar M} D} \right)_{\bar M} X$ of $_{\bar M} X$ in terms of (α,C, D) and $\bar M$ . This means that a lot of given birth and death processes can be embedded in one and the same birth and death process. If $k \in \bar E$ and $\bar M = \left\{ k \right\}$ , we decompose X into $_k X, k \in \bar E$ .

Multifunctional AlPO_(4)reconstructed LiMn_(2)O_(4)surface for electrochemical lithium extraction from brine

LiMn_(2)O_(4)(LMO)electrochemical lithium-ion pump has gained widespread attention due to its green,high efficiency,and low energy consumption in selectively extracting lithium from brine.However,collapse of crystal structure and loss of lithium extraction capacity caused by Mn dissolution loss limits its industrialized application.Hence,a multifunctional coating was developed by depositing amorphous AlPO_(4)on the surface of LMO using sol-gel method.The characterization and electrochemical performance test provided insights into the mechanism of Li^(+)embedment and de-embedment and revealed that multifunctional AlPO_(4)can reconstruct the physical and chemical state of LMO surface to improve the interface hydrophilicity,promote the transport of Li^(+),strengthen cycle stability.Remarkably,after 20 cycles,the capacity retention rate of 0.5AP-LMO reached 93.6%with only 0.147%Mn dissolution loss.The average Li^(+)release capacity of 0.5AP-LMO//Ag system in simulated brine is 28.77 mg/(g h),which is 90.4%higher than LMO.Encouragingly,even in the more complex Zabuye real brine,0.5AP-LMO//Ag can still maintain excellent lithium extraction performance.These results indicate that the 0.5AP-LMO//Ag lithium-ion pump shows promising potential as a Li^(+)selective extraction system.

基于Transformer结构增强的神经网络架构搜索性能预测器

神经网络架构搜索(Neural Architecture Search,NAS)作为一种通过搜索算法设计神经网络架构的方法,在计算机视觉和自然语言处理等领域得到广泛应用,相较于人工设计网络,NAS方法可以减少设计成本并提高模型性能.但是NAS的性能评估需要对候选架构进行大量训练,由此带来的计算量占整个NAS的80%以上.为降低计算开销和时间成本,近年来已提出许多基于Transformer的NAS预测器,由于Transformer出色的结构编码能力可以更好地表示拓扑信息,因而得到广泛应用.但是,现有基于Transformer的NAS预测器依然存在三个问题:其一是在预处理阶段,传统的One-hot编码方式描述节点特征的能力较弱,只能区分不同操作节点类型,而难以表达操作的细节特征,如卷积核尺寸等.其二是在编码阶段,Transformer的自注意力机制导致模型结构信息缺失;其三是在评估阶段,现有的Transformer预测器仅使用多层感知机(Multilayer Perceptron,MLP)对前向传播图进行精度预测,忽略了反向传播梯度流对预测精度的影响,因此难以真正拟合NAS评估中的正、反向交替信息流图,导致预测器精度与实际运行精度误差波动极大(10%~90%).为解决上述问题,本文提出了一种基于Transformer结构增强的NAS性能预测方法.首先,在预处理阶段,本文提出了一种超维嵌入方法增加输入数据维度以强化节点操作的参数描述能力,其次,在编码阶段将Transformer编码后的信息与图结构信息共同输人一个图卷积网络(Graph Convolutional Network,GCN),弥补由自注意力机制引起的结构缺失.最后,在性能评估阶段,本文构建了同时包含前向传播和反向传播的全训练图,并将数据集信息、图结构编码与梯度编码共同输入到GCN网络预测器中,使预测结果更贴近模型真实性能.实验结果表明,本方法与目前最先进方法相比,肯德尔相关系数提高了7.45%,训练时间减少了1.55倍。

Oxygen functionalization-assisted anionic exchange toward unique construction of flower-like transition metal chalcogenide embedded carbon fabric for ultra-long life flexible energy storage and conversion

The metal-organic framework(MOF)derived Ni–Co–C–N composite alloys(NiCCZ)were“embedded”inside the carbon cloth(CC)strands as opposed to the popular idea of growing them upward to realize ultrastable energy storage and conversion application.The NiCCZ was then oxygen functionalized,facilitating the next step of stoichiometric sulfur anion diffusion during hydrothermal sulfurization,generating a flower-like metal hydroxysulfide structure(NiCCZOS)with strong partial implantation inside CC.Thus obtained NiCCZOS shows an excellent capacity when tested as a supercapacitor electrode in a three-electrode configuration.Moreover,when paired with the biomass-derived nitrogen-rich activated carbon,the asymmetric supercapacitor device shows almost 100%capacity retention even after 45,000 charge–discharge cycles with remarkable energy density(59.4 Wh kg^(-1)/263.8μWh cm^(–2))owing to a uniquely designed cathode.Furthermore,the same electrode performed as an excellent bifunctional water-splitting electrocatalyst with an overpotential of 271 mV for oxygen evolution reaction(OER)and 168.4 mV for hydrogen evolution reaction(HER)at 10 mA cm−2 current density along with 30 h of unhinged chronopotentiometric stability performance for both HER and OER.Hence,a unique metal chalcogenide composite electrode/substrate configuration has been proposed as a highly stable electrode material for flexible energy storage and conversion applications.

Application of buried auricular point combined with Wenjing Sanhan prescription in arteriosclerosis obliterans patients with resting pain

BACKGROUND Research on the combined use of ear acupoint embedding beans and warming meridians with cold-dispersing formulas for alleviating resting pain in patients with arteriosclerosis obliterans(ASO)remains limited.AIM To explore the therapeutic efficacy of auricular point embedding beans combined with Wenjing Sanhan prescription in alleviating resting pain in patients with lower-limb ASO.METHODS A total of 100 patients with ASO experiencing resting pain who were treated at our hospital from January 2022 to January 2023 were enrolled.They were randomly allocated into two groups using a double-blind approach.The control group was treated using a warming meridian with a cold-dispersing formula,while the study group received additional treatment with ear acupoint embedding beans.The clinical efficacy,ankle-brachial artery pressure ratio,hemorheological indicators,and traditional Chinese medicine symptom scores were compared between the two groups.RESULTS The clinical efficacy rate in the study group was significantly higher(94.00%)than that in the control group(72.00%,P<0.05).Moreover,the ankle-brachial artery pressure ratio was significantly higher in the study group after treatment(P<0.05).Hemorheological parameters,including whole blood viscosity,plasma viscosity(1.83±0.11)mPa/s,fibrinogen levels(3.30±0.21)g/L,platelet adhesion rate(49.87%±10.51%),and erythrocyte aggregation index(1.79±0)were improved in the study group compared to the control group.In addition,the scores for decreased skin temperature(1.41±0.26),intermittent claudication(1.30±0.20),and resting pain(1.23±0.31)were significantly lower in the study group than those in the control group(all P<0.05).The level of oxidative stress in the study group also exhibited significant improvement(P<0.05),and the levels of inflammatory factors were considerably lower than those in the control group.CONCLUSION The combination of ear point embedding beans and Wenjing Sanhan prescription demonstrates promising clinical efficacy in alleviating resting pain associated with ASO.

A Linked List Encryption Scheme for Image Steganography without Embedding

Information steganography has received more and more attention from scholars nowadays,especially in the area of image steganography,which uses image content to transmit information and makes the existence of secret information undetectable.To enhance concealment and security,the Steganography without Embedding(SWE)method has proven effective in avoiding image distortion resulting from cover modification.In this paper,a novel encrypted communication scheme for image SWE is proposed.It reconstructs the image into a multi-linked list structure consisting of numerous nodes,where each pixel is transformed into a single node with data and pointer domains.By employing a special addressing algorithm,the optimal linked list corresponding to the secret information can be identified.The receiver can restore the secretmessage fromthe received image using only the list header position information.The scheme is based on the concept of coverless steganography,eliminating the need for any modifications to the cover image.It boasts high concealment and security,along with a complete message restoration rate,making it resistant to steganalysis.Furthermore,this paper proposes linked-list construction schemeswithin theproposedframework,which caneffectively resist a variety of attacks,includingnoise attacks and image compression,demonstrating a certain degree of robustness.To validate the proposed framework,practical tests and comparisons are conducted using multiple datasets.The results affirm the framework’s commendable performance in terms of message reduction rate,hidden writing capacity,and robustness against diverse attacks.

Intelligent casting:Empowering the future foundry industry

Emerging technological advances are reshaping the casting sector in latest decades.Casting technology is evolving towards intelligent casting paradigm that involves automation,greenization and intelligentization,which attracts more and more attention from the academic and industry communities.In this paper,the main features of casting technology were briefly summarized and forecasted,and the recent developments of key technologies and the innovative efforts made in promoting intelligent casting process were discussed.Moreover,the technical visions of intelligent casting process were also put forward.The key technologies for intelligent casting process comprise 3D printing technologies,intelligent mold technologies and intelligent process control technologies.In future,the intelligent mold that derived from mold with sensors,control devices and actuators will probably incorporate the Internet of Things,online inspection,embedded simulation,decision-making and control system,and other technologies to form intelligent cyber-physical casting system,which may pave the way to realize intelligent casting.It is promising that the intelligent casting process will eventually achieve the goal of real-time process optimization and full-scale control,with the defects,microstructure,performance,and service life of the fabricated castings can be accurately predicted and tailored.