The Relationship Between Financial Constraints and Cash-Cash Flow Sensitivity of Chinese Listed Companies

With the cash-cash flow sensitivity theory originally proposed by Heitor et al, this paper conducts an empirical study on the relationship between the cash-cash flow sensitivity and the financial constraint of A-share listed companies in China. The results indicate： （1） the financially constrained firms display significantly positive cash- cash flow sensitivities, while financially unconstrained firms show insignificant cash-cash flow sensitivities. （2） The cash-cash flow sensitivity is significantly negatively correlated with firms＇ earning profit ability and repaying debt ability, and the degree of the financial constraint changes in opposite directions with firms＇ earning profit ability and repaying debt ability, thus the cash-cash flow sensitivity and the degree of the financial constraint changes in the same direction.

A semi-analytical model for coupled flow in stress-sensitive multi-scale shale reservoirs with fractal characteristics

A large number of nanopores and complex fracture structures in shale reservoirs results in multi-scale flow of oil. With the development of shale oil reservoirs, the permeability of multi-scale media undergoes changes due to stress sensitivity, which plays a crucial role in controlling pressure propagation and oil flow. This paper proposes a multi-scale coupled flow mathematical model of matrix nanopores, induced fractures, and hydraulic fractures. In this model, the micro-scale effects of shale oil flow in fractal nanopores, fractal induced fracture network, and stress sensitivity of multi-scale media are considered. We solved the model iteratively using Pedrosa transform, semi-analytic Segmented Bessel function, Laplace transform. The results of this model exhibit good agreement with the numerical solution and field production data, confirming the high accuracy of the model. As well, the influence of stress sensitivity on permeability, pressure and production is analyzed. It is shown that the permeability and production decrease significantly when induced fractures are weakly supported. Closed induced fractures can inhibit interporosity flow in the stimulated reservoir volume (SRV). It has been shown in sensitivity analysis that hydraulic fractures are beneficial to early production, and induced fractures in SRV are beneficial to middle production. The model can characterize multi-scale flow characteristics of shale oil, providing theoretical guidance for rapid productivity evaluation.

Introducing Fractal Dimension to Estimation of Soil Sensitivity to Preferential Flow

Food dye Brilliant Blue was introduced as the tracer in a dye-tracing experiment to obtain dye profile patterns of sandy loam soil, aeolian sandy soil, percolating paddy soil and permeable paddy soil. The dyed soil profiles were then photographed and the photos were scanned into a computer. Edited with certain software, only the dyed areas were left on the profile photos, which indicted the preferential flow paths for water and solute transport. Fractal dimensions of the dye patterns were calculated according to Arnold's function. Soil particle size distribution was analyzed by pipette method. The regression analysis showed that there was significant relationship between soil clay content and fractal dimension D of the dye pattern of soil profile. Based on the experiment results, the possibility of introducing fractal dimension to estimation of soil sensitivity to preferential flow is discussed.

Numerical modeling and parametric sensitivity analysis of heat transfer and two-phase oil and water flow characteristics in horizontal and inclined flowlines using OpenFOAM

Estimating the oil-water temperatures in flowlines is challenging especially in deepwater and ultra-deepwater offshore applications where issues of flow assurance and dramatic heat transfer are likely to occur due to the temperature difference between the fluids and the surroundings. Heat transfer analysis is very important for the prediction and prevention of deposits in oil and water flowlines, which could impede the flow and give rise to huge financial losses. Therefore, a 3D mathematical model of oil-water Newtonian flow under non-isothermal conditions is established to explore the complex mechanisms of the two-phase oil-water transportation and heat transfer in different flowline inclinations. In this work, a non-isothermal two-phase flow model is first modified and then implemented in the InterFoam solver by introducing the energy equation using OpenFOAM® code. The Low Reynolds Number (LRN) k-ε turbulence model is utilized to resolve the turbulence phenomena within the oil and water mixtures. The flow patterns and the local heat transfer coefficients (HTC) for two-phase oil-water flow at different flowlines inclinations (0°, +4°, +7°) are validated by the experimental literature results and the relative errors are also compared. Global sensitivity analysis is then conducted to determine the effect of the different parameters on the performance of the produced two-phase hydrocarbon systems for effective subsea fluid transportation. Thereafter, HTC and flow patterns for oil-water flows at downward inclinations of 4°, and 7° can be predicted by the models. The velocity distribution, pressure gradient, liquid holdup, and temperature variation at the flowline cross-sections are simulated and analyzed in detail. Consequently, the numerical model can be generally applied to compute the global properties of the fluid and other operating parameters that are beneficial in the management of two-phase oil-water transportation.

Optimization of heat transfer in the thermal Marangoni convective flow of a hybrid nanomaterial with sensitivity analysis

The heat transfer rate of the thermal Marangoni convective flow of a hybrid nanomaterial is optimized by using the response surface methodology(RSM).The thermal phenomenon is modeled in the presence of a variable inclined magnetic field,thermal radiation,and an exponential heat source.Experimentally estimated values of the thermal conductivity and viscosity of the hybrid nanomaterial are utilized in the calculation.The governing intricate nonlinear problem is treated numerically,and a parametric analysis is carried out by using graphical visualizations.A finite difference-based numerical scheme is utilized in conjunction with the 4-stage Lobatto IIIa formula to solve the nonlinear governing problem.The interactive effects of the pertinent parameters on the heat transfer rate are presented by plotting the response surfaces and the contours obtained from the RSM.The mono and hybrid nanomaterial flow fields are compared.The hybrid nanomaterial possesses enhanced thermal fields for nanoparticle volume fractions less than 2%.The irregular heat source and the thermal radiation enhance the temperature profiles.The high level of the thermal radiation and the low levels of the exponential heat source and the angle of inclination(of the magnetic field)lead to the optimized heat transfer rate(Nux=7.46275).

Traffic flow sensitivity to visco-elasticity

This letter reports traffic flow sensitivity to visco-elasticity, with the traffic flow modeling briefly described at first and then used to do traffic flow simulations whose results can reflect the properties of spatial-temporal evolution of ring traffic flow. It reveals that visco-elasticity plays crucial role in formation of traffic flow patterns, implying that self-organization of traffic flow is crucial in determining traffic flow status.

SENSITIVITY COEFFICIENTS OF SINGLE-PHASE FLOW IN LOW-PERMEABILITY HETEROGENEOUS RESERVOIRS

Theoretical equations for computing sensitivity coefficients of wellbore pressures to estimate the reservoir parameters in low-permeability reservoirs conditioning to non-Darcy flow data at low velocity were obtained. It is shown by a lot of numerical calculations that the wellbore pressures are much more sensitive to permeability very near the well than to permeability a few gridblocks away from the well. When an initial pressure gradient existent sensitivity coefficients in the region are closer to the active well than to the observation well. Sensitivity coefficients of observation well at the line between the active well and the observation well are influenced greatly by the initial pressure gradient.

Development of Supply Chain Finance, Financial Constraints and Cash Flow Sensitivity

This paper used the Chinese listing Corporation financial data （2003-2013） to study the relationship between the supply chain finance development, SME financing constraints and cash flow. The study found that the small and medium-sized enterprise has obvious cash flow sensitivity, explaining it is subjected to the larger financing constraints. The development of supply chain finance can alleviate the financing constraints of SMEs, but for large enterprises it is unable to play a corresponding role.

Pore-scale study of the pressure-sensitive effect of sandstone and its influence on multiphase flows

The pressure-sensitive effect on the pore structure of sandstone was investigated using X-ray computed micro-tomography and QEMSCAN quantitative mineral analysis. In a physical simulation study, we extracted the pore network model from digital cores at different confining pressures and evaluated the effect of pressure sensitivity on the multiphase displacement process. In both the pore network model and QEMSCAN scanning, the pore structure was observed to be damaged under a high confining pressure. Due to their different scales, the pores and throats exhibited inhomogeneous changes; further, the throats exhibited a significant variation compared to that exhibited by the pores. Meanwhile, the heterogeneity of the pore structure under the two aforementioned activities was aggravated by the elastic-plastic deformation of the pore structure.The pressure-sensitive effect increased the proportion of mineral particles, such as quartz(the main component of the core skeleton), and reduced the proportion of clay minerals. The clay minerals were originally attached to the pore walls or interspersed in the pores; however, as the pressure increased, the clay minerals accumulated in the pores resulting in blockage of the pores. While simulating the multiphase displacement process, increasing the confining pressure was observed to severely restrict the flowability of oil and water. This study promises to improve the efficiency of reservoir development in terms of oil and gas exploitation.

Effects of physical parameter range on dimensionless variable sensitivity in water flooding reservoirs

The similarity criterion for water flooding reservoir flows is concerned with in the present paper. When finding out all the dimensionless variables governing this kind of flow, their physical meanings are subsequently elucidated. Then, a numerical approach of sensitivity analysis is adopted to quantify their corresponding dominance degree among the similarity parameters. In this way, we may finally identify major scaling law in different parameter range and demonstrate the respective effects of viscosity, permeability and injection rate.

Analysis of key parameters sensitivity and calibration accuracy of signal timing algorithm

A theoretical sensitivity analysis of total lost timeand saturated flow rate is conducted based on the methodproposed in the Highway Capacity Manual （HCM）. Inaddition, the accuracy of the timing calculation algorithmsuggested in the HCM is verified using field data from threeintersections. It is demonstrated that there is a positivecorrelation between the estimation error rates of the signalcycle length and the phase lost time. Also, the estimated valueof saturated flow rate must meet the specific requirementsunder different saturated conditions to guarantee the accuracyof the signal cycle length. However, through analysis of fielddata collected on the discharge headway in three intersections,it is also found that, if the 4th vehicle is set as the initial spotfor the stable discharge headway, as is recommended in theHCM, the error of the phase lost time will be over 40% whenthe line length is over 10 vehicles. Moreover, the calculationerror for signal cycle length is not guaranteed to fall within the15% range when the length of line is over 15 vehicles. It issuggested that, to improve the applicability of the HCMmethod, a more accurate description of the distributedregularity of the discharge headway is necessary whencalibrating key parameters.

Comparative studies of serum-free media and detection techniques for <i>in vitro</i>drug sensitivity assessment of <i>Plasmodium falciparum</i>

Malaria continues to be a devastating disease. In a previous study, we formulated a chemically defined culture medium that is able to sustain the complete intraerythrocytic growth of Plasmodium falciparum. We tested the feasibility of using the medium (CDRPMI) as well as human serum-free media enriched with commercially available human-serum substitutes (GFSRPMI and ALBRPMI) to assess the drug sensitivity of P. falciparum, using chloroquine diphosphate (CQ) and dihydroartemisinin (DHART) as conventional antimalarial drugs. Growth inhibition was measured by four different methods: flow cytometry with SYBR Green I (FCM), microscopy (Giemsa method), enzymatic estimation of parasite lactate dehydrogenase (pLDH), and histidine-rich protein 2 (HRPII) determination. In drug sensitivity tests on asynchronous parasites cultured for 96 h in the presence of drugs, the dose-response curves were similar and differences in the 50% growth inhibition concentrations for the drugs, which were estimated by the four methods, were not statistically significant for the three culture media. The effect of the drugs on the growth of synchronous parasites at the ring stage was also assessed in micro-volume tests by three different methods of FCM: tracking fluorescent erythrocytes, schizont test, and merozoite test. Dose-response curves for the drugs were similar, and differences in the 50% growth inhibition concentrations were not statistically significant for CDRPMI and GFSRPMI. Thus CDRPMI as well as GFSRPMI and ALBRPMI can be similarly useful media for drug sensitivity testing of P. falciparum. The FCM, pLDH and HRPII estimations were fast and reliable detection methods, with FCM allowing schizont and merozoite tests to be performed with shorter periods of culture.

Hydrodynamics and Sensitivity Analysis of a Williamson Fluid in Porous-Walled Wavy Channel

In this work,a steady,incompressible Williamson fluid model is investigated in a porous wavy channel.This situation arises in the reabsorption of useful substances from the glomerular filtrate in the kidney.After 80%reabsorption,urine is left,which behaves like a thinning fluid.The laws of conservation of mass and momentum are used to model the physical problem.The analytical solution of the problem in terms of stream function is obtained by a regular perturbation expansion method.The asymptotic integration method for small wave amplitudes and the RK-Fehlberg method for pressure distribution has been used inside the channel.It is demonstrated that the forward flow becomes fast in the narrow region(at x=0.75),which dominates the upward flow inside the channel.To study the impact of model parameters on outputs,we applied normalized local sensitivity analysis and noticed that the most influential parameter for the longitudinal velocity profile is the dimensionless wave amplitude.The reabsorption parameter is sensitive for transverse velocity in the narrow region,and the Weissenberg number has a strong effect on the pressure inside the channel.Further,the least sensitive parameters for the velocity components and pressure have been identified.

Numerical analysis of downward progressive landslides in long natural slopes with sensitive clay

Landslides occurring in sensitive clay often result in widespread destruction,posing a significant risk to human lives and property due to the substantial decrease in undrained shear strength during deformation.Assessing the consequences of these landslides is challenging and necessitates robust numerical methods to comprehensively investigate their failure mechanisms.While studies have extensively explored upward progressive landslides in sensitive clays,understanding downward progressive cases remains limited.In this study,we utilised the nodal integration-based particle finite element method(NPFEM)with a nonlinear strain-softening model to analyse downward progressive landslides in sensitive clay on elongated slopes,induced by surcharge loads near the crest.We focused on elucidating the underlying failure mechanisms and evaluating the effects of different soil parameters and strainsoftening characteristics.The simulation results revealed the typical pattern for downward landslides,which typically start with a localised failure in proximity to the surcharge loads,followed by a combination of different types of failure mechanisms,including single flow slides,translational progressive landslides,progressive flow slides,and spread failures.Additionally,inclined shear bands occur within spread failures,often adopting distinctive ploughing patterns characterised by triangular shapes.The sensitive clay thickness at the base,the clay strength gradient,the sensitivity,and the softening rate significantly influence the failure mechanisms and the extent of diffused displacement.Remarkably,some of these effects mirror those observed in upward progressive landslides,underscoring the interconnectedness of these phenomena.This study contributes valuable insights into the complex dynamics of sensitive clay landslides,shedding light on the intricate interplay of factors governing their behaviour and progression.

Sensitivity Analysis of Geological Parameters Influencing a Solute Transport from a Deep Repository of Spent Nuclear Fuel

When evaluating Nuclear Waste DGR Safety, it is necessary to confirm its safety in a long run and above all its safety towards the biosphere which is more precisely that the biosphere will not be in any hazard caused by radioactive substances, With the aid of geologists, a model of a hypothetical area was elaborated and described with the use of geological and hydrogeological parameters. The volume of isotopes released out of the massif at the borderline of the near/far field from the DGR was determined. The paper results showed that ground water flow and transport of substances within the area were first to be determined. The Flow123D SW was used for the determination. The resulting outcome represents a determination of transported substances concentration depending on time. The disadvantage of the model is the fact that all the input parameters were set deterministically. The problem is solved by using the sensitivity analysis （changing the input parameters） or using the Monte Carlo Method. The major results are： calculations of the radionuclide concentrations in the elements depending on time and determination of parameters that have the biggest impact on the sensitivity of the whole model.

Effect of resistance exercise on insulin sensitivity of skeletal muscle

Insulin resistance(IR)is the common pathophysiological basis of many metabolic diseases.IR is characterized by decreased glucose uptake in skeletal muscle and adipose tissue,especially in skeletal muscle.Skeletal muscle is the main target tissue of glucose uptake under insulin stimulation.Glucose uptake by skeletal muscle is complex,and it is controlled by many pathways.The PI3K/AKt/GSK-1 signaling pathway is not only the main pathway for insulin signal transduction but also an important mechanism for regulating blood glucose.From the binding of insulin to its receptors on the surface of target cells to the transportation of glucose from extracellular fluid to skeletal muscle,a series of signal transduction processes is completed,any of which potentially affects the physiological effects of insulin and leads to IR.Resistance exercise(RT)can reduce skeletal muscle IR and effectively improve blood glucose control and glycosylated hemoglobin level in patients with type 2 diabetes mellitus(T2DM).However,the exact mechanism by which RT improves skeletal muscle IR remains unclear.Therefore,this paper discusses the above problems by tracking the progress of the literature to deepen the correlation between RT and skeletal muscle insulin sensitivity and provide further evidence for the application of exercise therapy in IR.In conclusion,RT mainly improves insulin sensitivity of skeletal muscle by increasing muscle mass,microvascular blood flow,and glucose transporter-4 expression in skeletal muscle,as well as by reducing lipid accumulation and inflammation in skeletal muscle.Thus,it is potentially useful in the prevention and treatment of T2DM.

基于Visual MODFLOW大水矿山深部开采矿坑涌水量预测

矿产资源的不断开发导致矿坑涌、突水现象愈加频繁,此类问题多发生于大水矿山,为更好指导大水矿山深部开采工作,准确预测矿山深部开采矿坑涌水量至关重要。结合某矿区勘察资料、水文地质条件和观测井实测水位数据,利用Visual MODFLOW软件建立矿区水文地质数值模型,进行稳态与非稳态校正以及相关参数敏感性分析;根据该矿区-150 m水平矿坑真实涌水量拟合分析Drain模块水力传导系数值,运用识别后模型对矿山深部开采矿坑涌水量预测,结果表明-200、-250、-300、-350 m等不同水平矿坑正常涌水量为17209.82、18896.20、21299.31、23494.10 m^(3)/d,预测结果可为矿山防治水工作提供依据,以及为工程安全开挖提供保障。

Differences of Gas Lift Design between Deviated and Vertical Wells and the Analysis of Sensitivity Parameters

尽管气举越来越多地被应用到大斜度井、水平井的举升采油中,但倾斜井气举设计与直井气举设计存在什么差异,这些差异随倾斜角度的增大将怎样变化,以及哪些气举设计所需参数对这种差异比较敏感,即如何对倾斜井气举设计所需参数进行合理选择,以便对倾斜井气举设计进行优化的研究较少,这也一直是倾斜井合理气举设计的难点问题。鉴于此,笔者以某油田一口倾斜井为例,通过实测数据进行了倾斜井产能预测方法优选和多相管流压力计算方法优选,然后在该基础上采用等套压降气举设计方法对比分析了倾斜井气举设计与同等条件下直井气举设计的差异,并逐一分析了各种气举设计所需重要参数分别取不同值时气举设计注气深度和产量随井斜角度的变化规律,从而得到了倾斜井气举设计的敏感性参数,可为倾斜井气举设计的参数优化和调整提供参考依据,是倾斜井气举高效生产的有力保障。

二维超声联合四维彩超HD-flow彩色血流显像在产前诊断先天性心脏发育异常中的应用

目的探讨二维超声联合四维彩超超高细微分辨血流技术(HD-flow)彩色血流显像在产前诊断先天性心脏发育异常中的临床应用价值。方法选取2016年7月至2018年2月在小榄人民医院行产前超声检查并分娩的单胎妊娠孕妇2 200例,先对所有入组的孕妇进行二维超声检查,二维超声检查提示胎儿疑似宫内心脏发育异常的孕妇再联合应用四维彩超HD-flow彩色血流显像进行检查。将进行二维超声的检查结果作为对照组,将二维超声+四维彩超HD-flow彩色血流显像的检查结果作为研究组,将出生后新生儿的心脏超声诊断结果或引产后胎儿心脏病理诊断结果作为金标准。观察所有入组孕妇中胎儿先天性心脏发育异常(FCHD)的检出情况,比较不同检查方式诊断FCHD胎儿的准确率。结果2 200例胎儿经随访诊断证实有56例胎儿存在先天性心脏发育异常,占所有入组胎儿总数的2.5%(56/2 200),其中,动脉弓畸形6例,三尖瓣畸形3例,完全性大动脉转位4例,右室双出口4例,单心室(房)4例,法洛四联症(TOF)8例,心内膜垫缺损4例,单纯性室间隔缺损9例、左心发育不良4例,肺动脉瓣闭锁5例,肺动脉瓣狭窄2例,永存动脉干3例;二维超声共检查出42例FCHD,有14例误诊或漏诊,准确率为75.0%,二维超声+四维彩超HD-flow彩色血流显像检查共查出52例FCHD,误诊或漏诊4例,准确率为92.8%,研究组的准确率高于对照组,差异具有统计学意义(P<0.05);研究组的灵敏度为92.1%、特异度为94.5%,对照组的灵敏度为60.7%、特异度为90.3%,研究组的灵敏度及特异度明显高于对照组,差异均有统计学意义(P<0.05)。结论二维超声联合四维彩超HD-flow彩色血流显像检查能显著提高FCHD的产前诊断准确率,具有较高的灵敏度及特异度,值得临床推广应用。

Plastic flow behavior of superalloy GH696 during hot deformation

In order to investigate the hot deformation behavior of superalloy GH696, isothermal compression experiments were carried out at deformation temperatures of 880?1120 °C and strain rates of 0.01?10 s?1. And the deformation amount of all the samples was 50%. The strain rate sensitivity exponent (m) and strain hardening exponent (n) under different deformation conditions were calculated, meanwhile the effects of the processing parameters on the values ofm andn were analyzed. The results show that the flow stress increases with the increase of strain rate and the decrease of deformation temperature. The value ofm increases with the increase of deformation temperature and decreases with the increase of strain rate, while the value ofn decreases with the increase of deformation temperature. A novel flow stress model during hot deformation of superalloy GH696 was also established. And the calculated flow stress of the alloy is in good agreement with the experimental one.