Double-porosity rock model and squirt flow in the laboratory frequency band

Biot theory research has been extended to the multi-scale heterogeneity in actual rocks. Focused on laboratory frequency bandwidth studies, we discuss the relationships between double-porosity and BISQ wave equations, analytically derive the degeneration method for double-porosity＇s return to BISQ, and give three necessary conditions which the degeneration must satisfy. By introducing dynamic permeability and tortuosity theory, a full set of dynamic double-porosity wave equations are derived. A narrow band approximation is made to simplify the numerical simulation for dynamic double-porosity wavefields. Finally, the pseudo-spectral method is used for wave simulation within the laboratory frequency band （50 kHz）. Numerical results have proved the feasibility for dynamic double-porosity＇s description of squirt flow and the validity of the quasi-static approximation method.

暗物质粒子探测器触发逻辑测试系统的设计和实现

作为暗物质粒子探测器(DAMPE,Dark Matter Particle Explorer)的一部分,触发系统主要用于判选所需探测的目标粒子(高能电子和伽玛射线)事例,剔除非目标粒子事例.触发系统由触发探测器和触发判选逻辑电路组成.介绍了触发地检测试系统和宇宙线触发系统的设计和功能实现.触发地检系统实现了对触发判选逻辑电路的电子学验证;另外,配合宇宙线触发系统对部分触发逻辑和触发效率进行了测试.主要介绍了触发系统的测试方法和一些初步测试结果.

云南西双版纳(曼桂)目击陨石的热变质和冲击变质研究

曼桂陨石是新近(2018年6月1日)陨落在云南西双版纳地区的目击球粒陨石,其中的主要矿物为橄榄石(Fa24.3±0.6)、斜方辉石(Fs20.6±0.5Wo0.4±0.2)、长石(An11-12Or2-4)、铁镍金属和陨硫铁,次要矿物为铬铁矿、白磷钙矿等.橄榄石和辉石的化学成分表明曼桂陨石属于L型普通球粒陨石.陨石中球粒很少且轮廓不清晰,基质矿物普遍经历过重结晶,重结晶矿物颗粒粒径较大,高钙辉石粒径25–30μm,长石颗粒大多超过50μm,说明该陨石属于6型岩石类型.橄榄石和辉石颗粒中发育有波状消光、嵌晶块状消光现象、平面裂隙和面状变形构造,长石熔长石化并不完全,陨石中观察到宽度不等且纵横交错的冲击熔融脉,表明曼桂普通球粒陨石受到的冲击变质作用可以达到S5级以上.通过熔融脉中的矿物组合推断出熔融脉中矿物经历的压力在15–16 GPa左右.

Suture granuloma of the abdominal wall with intra-abdominal extension 12 years after open appendectomy

Most complications after appendectomy occur within ten days; however, we report the unusual case of a suture granuloma 12 years after open appendectomy. The afebrile 75-year-old woman presented with a slightly painful palpable mass in the right lower abdomen. There was no nausea or vomiting and bowel movements were normal. She lost 10 kg during the 3 mo before presentation. The patient had undergone an appendectomy 12 years previously. Physical examination revealed a tender mass, 10 cm in diameter, under the appendectomy scar. The preoperative laboratory findings, tumor markers and plain abdominal radiographs were normal. Multi-slice computed tomography scanning showed an inhomo-genous abdominal mass with minimal vascularization in the right lower abdomen 8.6cm×8cm×9 cm in size which communicated with the abdominal wall. The abdominal wall was thickened, weak and bulging. The abdominal wall mass did not communicate with the cecum or the ascending colon. Complete excision of the abdominal wall mass was performed via median laparotomy. Histopathological examination revealed a granuloma with a central abscess. This case report demonstrates that a preoperative diagnosis of abdominal wall mass after open appendectomy warrants the use of a wide spectrum of diagnostic modalities and consequently different treatment options.

Purification of Crude Glycerol from Waste Cooking Oil Based Biodiesel Production by Orthogonal Test Method

Purification of original crude glycerol obtained from biodiesel production was conducted in a laboratory scale equipment by means of a combined chemical and physical treatment method based upon repeated cycles of acidification of liquid phase to the desired pH value by using 5.85% H3PO4 solution for pH value adjustment, and the mixture was kept at 70 ℃ for 60 rain to make phase separation for obtaining a glycerol-rich middle phase. The yield of crude glycerol reached 81.2%. Subsequently, upon reaction of the obtained glycerol phase with 0.03% of sodium oxalate at 80 ℃ for 30 min the impurity removal rate was equal to 19.8%. The fraction boiling between 164 ℃ and 200 ℃ was collected by vacuum distil- lation followed by decolorization with 2% of active carbon at 80 ℃ for two times to yield the product glycerol with an ac- ceptable purity of 98.10%.

Mesomechanical simulation of direct shear test on outwash deposits with granular discrete element method

The mechanical properties of outwash deposits which are taken as unconsolidated geo-materials with the characteristics of non-uniformity, heterogeneity and multiphase have attracted much attention in engineering. According to the results of laboratory direct shear test on the remolded samples, the soil particle parameters of numerical model based on in-situ particle size cumulative curves and 3D granular discrete element method were determined. Then, numerical experiments on different lithology, stone content and gradation composition were conducted. The results show that it is not a flat surface but a shear band that yields in the sample. The curve of particle velocity vs distance from the designed shear surface of test model that is taken as a datum plane in the vertical section of sample shows in "S" shape. The shear disturbance area is about twice the maximum diameter of stone blocks. The greater the stiffness of stone is, the rougher the shear surface is. The shear strength of outwash deposits is largely controlled by lithology and stone content, and the bite force between stone blocks is the root reason of larger friction angle. It is also shown that strain hardening and low shear dilatancy occur under high confining pressure as well as possibility of shear shrinkage. But it is easy to behave shear dilatation and strain softening under low confining pressure. The relationship between particle frictional coefficient and stone content presents an approximately quadratic parabola increase. The strain energy first increases and then drops with the increase of frictional energy. The cohesion increases with soil stiffness increasing but decreases with stone stiffness increasing. Numerical results are consistent with the laboratory test results of remolded samples, which indicate that this method can be a beneficial supplement to determine the parameters of engineering deposit bodies.

Intercalation Assembly Method and Intercalation Process Control of Layered Intercalated Functional Materials

Layered intercalated functional materials of layered double hydroxide type are an important class of functional materials developed in recent years. Based on long term studies on these materials in the State Key Laboratory of Chemical Resource Engineering in Beiiing University of Chemical Technology, the orinciole for the design of controlled intercalation processes in the light of tuture production processing requirements has been developed. Intercalation assembly methods and technologies have been invented to control the intercalation process for preparing layered intercalated materials with various structures and functions.

Probabilistic analysis of random contact force between geomembrane and granular material

A probabilistic method based on principle of maximum entropy was employed to analyze the randomness of contact force between geomembrane and granular material.The contact force distribution is exponential according to the proposed method and the grain size is the most important factor that affects the distribution of contact force.The proposed method is then verified by a series of laboratory experiments using glass beads and cobbles as granular material and a very thin pressure,indicating that film is firstly used in these experiments which give a reliable method to measure the contact force at each contact point.

Laboratory Detection and Diagnosis of Filoviruses

Ebola virus(EBOV) and Marburg virus(MARV),belonging to the Filoviridae family,emerged four decades ago and caused severe viral hemorrhagic fever in human and other primates.As high as 50-90% mortality,filoviruses can cause significant threats to public health.However,so far no specific and efficient vaccine has been available,nor have other treatment methods proved to be effective.It is of great importance to detect these pathogens specific,rapidly and sensitively in order to control future filovirus outbreaks.Here,recent progresses in the development of detection and diagnosis methods for EBOV and MARV are summarized.

Evaluation of Native Strains of Isaria fumosorosea （Wize） Against Anastrepha ludens （Loew） （Diptera： Tephritidae）

We evaluated the pathogenicity of six strains 1. fumosorosea to determine their potential as biological control agents of A. ludens by performing bioassays under laboratory conditions （25 ± 2 ℃, 60± 5% R.H and 12：12 h L： D） exposing larvae and pupae to a concentration of 1 × 10^8 conidia per milliliter using three different methods： direct spraying, spray of soil and submerged for both instars. The results showed that direct spraying method Pfr-612 strain showed the highest mortality （47%） in pupae while for larvae was strain HIB-27 to 46%. Regarding spray of soil Pfr-612 strain showed the highest percentage of mortality for pupae and larvae with 45 and 57% mortality, respectively. Finally, for the submerged method in pupae HIB-27 strain showed 62% mortality whereas in larvae HIB-32 strain showed 46%. These results indicate that A. ludens is susceptible in at least two instars to L fumosorosea and make this fungus a promising agent for control of the Mexican fruit fly.

An Alternative Approach for the Determination of Soil Water Mobility

A new laboratory method was proposed to establish an easily performed standard for the determination of mobile soil water close to real conditions during the infiltration and redistribution of water in a soil. It consisted of applying a water volume with a tracer ion on top of an undisturbed ring sample on a pressure plate under a known suction or pressure head. Afterwards, soil water mobility was determined by analyzing the tracer-ion concentration in the soil sample. Soil water mobility showed to be a function of the applied water volume. No relation between soil water mobility and applied pressure head could be established with data from the present cxperiment. A simple one- or two-parameter equation can be fitted to the experimental data to parameterize soil water mobility as a function of applied solute volume. Sandy soils showed higher mobility than loamy＂ soils at low values of applied solute volumes, and both sandy and loamy soils showed an almost complete mobility at high applied solute volumes.

A new manufacture method of backfill samples in lab——Illustrated with a case study

The differences between the formation processes of lab backfill samples and field backfill were analysed. An improved sampling mold, containing an outer box shell and inner sampling mold, was put forward. The new and traditional test molds were applied to make subsequent-backfill samples of Yong-ping Copper Mine. The observation of mass fraction and theory analysis of settlement and distribution of tailing particles were carried out. The research results show that the magnitude of the strength of the backfill forming in new mold is lower than that of backfill forming in traditional mold, and the biggest gap amounts to 36%.

Modeling approaches to pressure balance dynamic system in shield tunneling

In order to deal with modeling problem of a pressure balance system with time-delay, nonlinear, time-varying and uncertain characteristics, an intelligent modeling procedure is proposed, which is based on artificial neural network(ANN) and input-output data of the system during shield tunneling and can overcome the precision problem in mechanistic modeling(MM) approach. The computational results show that the training algorithm with Gauss-Newton optimization has fast convergent speed. The experimental investigation indicates that, compared with mechanistic modeling approach, intelligent modeling procedure can obviously increase the precision in both soil pressure fitting and forecasting period. The effectiveness and accuracy of proposed intelligent modeling procedure are verified in laboratory tests.

Operation Phase Problems of Prefabricated Residential Buildings with Integrated Autoclaved Aerated Concrete Panel Walls

Growing technical problems with the maintenance of precast concrete housing stock result in the search for efficient repair methods. The paper analyses the effects of flaws in the design concept and assembly accuracy of integrated AAC （autoclaved aerated concrete） panel walls, type GWO （Gazobetonowa Wielka P｜yta Ostonowa which means large cover panel from aerated concrete in English）, used as curtain walls in a system of precast concrete housing blocks erected in Lublin. The results of in-situ observations and laboratory tests of the panel walls have been described, and the opinion on the further use of these elements has been presented. As for the analysed case, there is no possibility of replacing damaged elements, thus, additional reinforcement with steel tendons has been proposed as a repair measure.

Laboratory investigation of axisymmetric single vacuum well point

Vacuum well point is a new but faint soft ground treatment method. This work focuses on the consolidation behavior of a reconstituted soft clayey specimen under vacuum well point combined with surcharge loading. The laboratory test was conducted through a vacuum-surcharge consolidation apparatus, and the vacuum loading scheme was adopted for vacuum pressure application to investigate the vacuum effect on soil consolidation. In the testing process, some key parameters such as vacuum pressure, pore water pressure and settlement deformation were timely recorded. Furthermore, the water content, void ratio and permeability coefficient of samples collected after loading were measured to reflect the consolidation characteristics. By comparing with the membrane system and membraneless system, something different was found for the vacuum well point method. The results indicate that the consolidation behavior of an axisymmetric single vacuum well point is almost identical to the behavior of vacuum preloading combined with prefabricated vertical drain(PVD), except for the distribution of the vacuum pressure along the well drain due to the structure of the vacuum well point. And the vacuum well point method may be useful for the improvement of soft clayey deposit in a certain depth.

Lightning Induced Surge on the Distribution Lines in the House near by the Lightning Point

Recently, a lightning surge is recognized as one of the biggest risks to the society. If the surges induced by lightning invade into low voltage distribution lines, there might be a possibility of giving some severe damages to the systems. Therefore, it is necessary to examine these induced phenomena. FDTD （finite difference time domain） method which treats objects as three-dimensional solid circuits is applied to analyze these induced phenomena. VSTL （Virtual Surge Test Lab.） is the surge analysis simulation program using FDTD method. In this paper, the lightning induced phenomena on the low voltage distribution line in the house are analyzed by using VSTL. In this paper, investigation results about induced surge when a lightning struck the point nearby the house, and about a suppressing effect of surges by comparing the results of analysis with and without SPD （surge protective device） are shown. As a result, it is confirmed that SPD is effective for suppressing lightning surge.

Study of a new one-way timing method

This paper combines the advantages of both common-view time transfer and one-way timing and proposes a new one-way timing method.Owing to the limitations in users capacity and real-time,common-view time transfer can not provide time service simultaneously for mass users.A zero baseline experiment is carried out to validate its feasibility.Experimental results indicate this new method can achieve a timing accuracy within 5 ns.Users with requirements of rigorous time can employ this method to keep time synchronized with timing labs.