Three-dimensional(3D)parametric measurements of individual gravels in the Gobi region using point cloud technique

Gobi spans a large area of China,surpassing the combined expanse of mobile dunes and semi-fixed dunes.Its presence significantly influences the movement of sand and dust.However,the complex origins and diverse materials constituting the Gobi result in notable differences in saltation processes across various Gobi surfaces.It is challenging to describe these processes according to a uniform morphology.Therefore,it becomes imperative to articulate surface characteristics through parameters such as the three-dimensional(3D)size and shape of gravel.Collecting morphology information for Gobi gravels is essential for studying its genesis and sand saltation.To enhance the efficiency and information yield of gravel parameter measurements,this study conducted field experiments in the Gobi region across Dunhuang City,Guazhou County,and Yumen City(administrated by Jiuquan City),Gansu Province,China in March 2023.A research framework and methodology for measuring 3D parameters of gravel using point cloud were developed,alongside improved calculation formulas for 3D parameters including gravel grain size,volume,flatness,roundness,sphericity,and equivalent grain size.Leveraging multi-view geometry technology for 3D reconstruction allowed for establishing an optimal data acquisition scheme characterized by high point cloud reconstruction efficiency and clear quality.Additionally,the proposed methodology incorporated point cloud clustering,segmentation,and filtering techniques to isolate individual gravel point clouds.Advanced point cloud algorithms,including the Oriented Bounding Box(OBB),point cloud slicing method,and point cloud triangulation,were then deployed to calculate the 3D parameters of individual gravels.These systematic processes allow precise and detailed characterization of individual gravels.For gravel grain size and volume,the correlation coefficients between point cloud and manual measurements all exceeded 0.9000,confirming the feasibility of the proposed methodology for measuring 3D parameters of individual gravels.The proposed workflow yields accurate calculations of relevant parameters for Gobi gravels,providing essential data support for subsequent studies on Gobi environments.

New criterion for rock joints based on three-dimensional roughness parameters

The shear behavior of rock joints is important in solving practical problems of rock mechanics. Three group rock joints with different morphologies are made by cement mortar material and a series of CNL(constant normal loading) shear tests are performed. The influences of the applied normal stress and joint morphology to its shear strength are analyzed. According to the experimental results, the peak dilatancy angle of rock joint decreases with increasing normal stress, but increases with increasing roughness. The shear strength increases with the increasing normal stress and the roughness of rock joint. It is observed that the modes of failure of asperities are tensile, pure shear, or a combination of both. It is suggested that the three-dimensional roughness parameters and the tensile strength are the appropriate parameter for describing the shear strength criterion. A new peak shear criterion is proposed which can be used to predict peak shear strength of rock joints. All the used parameters can be easily obtained by performing tests.

Estimating Hansen solubility parameters of organic pigments by group contribution methods

The Hansen solubility parameters(HSP)are frequently used for solvent selection and characterization of polymers,and are directly related to the suspension behavior of pigments in solvent mixtures.The performance of currently available group contribution(GC)methods for HSP were evaluated and found to be insufficient for computer-aided product design(CAPD)of paints and coatings.A revised and,for this purpose,improved GC method is presented for estimating HSP of organic compounds,intended for organic pigments.Due to the significant limitations of GC methods,an uncertainty analysis and parameter confidence intervals are provided in order to better quantify the estimation accuracy of the proposed approach.Compared to other applicable GC methods,the prediction error is reduced significantly with average absolute errors of 0.45 MPa^(1/2),1.35 MPa^(1/2),and 1.09 MPa^(1/2) for the partial dispersion(δD),polar(δP)and hydrogen-bonding(δH)solubility parameters respectively for a database of 1106 compounds.The performance for organic pigments is comparable to the overall method performance,with higher average errors forδD and lower average errors forδP andδH.

A THEORETIC METHOD TO PREDICT POLYMER SOLUBILITY PARAMETERS

A partition function and a complete thermodynamic description for pure polymer fluids have been investigated based on a self-avoid-walk lattice model. Caused by the introduction of Gibbs distribution into the Flory-Huggins theory, the partition function and the thermodynamic description depicted their dependence on temperature well. In the present study, we applied the theory to calculate polymer solubility parameters. The polymer solubility parameters predicted by our theory are well consistent with the experiment values.

Selection of Extraction Solvents for Bitumen from Indonesian Oil Sands through Solubility Parameters

Indonesian oil sands were systematically separated to investigate their basic composition.The extraction effects of the solvents with different Hilderbrand solubility parameters(HSPs)on the bitumen of Indonesian oil sands were compared.Furthermore,the Hansen solubility combination parameter(HSCP)and Teas triangle were used to explore rules in the separation of oil sands bitumen via solvent extraction.Finally,the saturates,aromatics,resins,and asphaltenes(SARA)fractions of the bitumen from Indonesian oil sands were analyzed.The results showed that the Indonesian oil sands were oil-wet with a bitumen content of 24.93%.The solvent extraction for bitumen could be accurately and conveniently selected based on the solubility parameter.When the HSPs of the extraction solvent were around 18–19 and the HSCPs were closer to a certain range(δ_(d)=17.5–18.0,δ_(p)=1–3.5,and δ_(h)=2–6),the extraction effect of bitumen from Indonesian oil sands improved,and the primary component affecting the extraction rate of bitumen were asphaltenes.

Simultaneous Removal of H_2S and Organosulfur Compounds from Liquefied Petroleum Gas Using Formulated Solvents: Solubility Parameter Investigation and Industrial Test

The performance of four formulated solvents(labeled as UDS-I, UDS-II, UDS-III, and UDS-IV) for removing methyl mercaptan from liquefied petroleum gas was predicted based on a two-dimensional solubility parameter theory. The calculation results show that UDS-IV has the closest solubility parameter to that of methyl mercaptan as compared with other tested solvents, indicating the strongest affinity and the highest solubility for methyl mercaptan. The industrial tests at a plant for desulfurization of LPG produced from the delayed coker have shown that the UDS solvents have the excellent performance for removal of organosulfur compounds(mainly methyl mercaptan). Although the sulfur loading dramatically increases, the total sulfur content of LPG treated with UDS-IV can be reduced by about 50% in comparison with N-methyl diethanolamine. In addition, UDS-IV has superior regeneration performance and selectivity for sulfur compounds over hydrocarbons. The industrial test and the solubility parameter calculation results are in good agreement with each other.

Antidiastole Value of Three-dimensional Ultrasonography and Power Doppler between Uterine Parenchyma Lumps and Endometrial Cancer:A Retrospective Study

Sometimes endometrial polyps,submucosal myomas,and endometrial cancer show similar findings under ultrasonography.The aim of this study was to assess the antidiastole value of blood flow parameters using three-dimensional(3D)power Doppler ultrasonography angiography(PDA)between endometrial cancer and uterine parenchyma lumps.The data of the blood flow indices in 3D-PDA including the vascularization index(VI),flow index(FI),and vascularization flow index(VFI)in 40 patients with endometrial cancer and 41 patients with uterine parenchyma lumps(endometrial polyps and submucosal myomas)were retrospectively analysed and compared utilizing Virtual Organ Computer-aided AnaLysis(VOCAL)software.The results showed that all the blood flow parameters(VI,FI,VFI)were significantly higher in women with endometrial cancer than in those with uterine parenchyma lumps(P<0.001).The area under the curve of ROC of VI,FI,and VFI was 0.98,0.84,and 0.97,respectively.Thus,the best predictor of endometrial carcinoma was VI with a sensitivity of 97.0% and a specificity of 91.0%.The optimal cutoff value of VI was 4.06%.Our data demonstrated that all of the blood flow signal parameters(including VI,FI,and VFI)in 3D power Doppler ultrasonography had significant antidiastole values between endometrial cancer and uterine parenchyma lumps to assist clinicians in properly diagnosing patients.

Effects of solubility parameter differences among PEG,PVP and CA on the preparation of ultrafiltration membranes:Impacts of solvents and additives on morphology,permeability and fouling performances

The effects of two different hydrophilic additives and two solvents on the membrane morphological structure,permeability property and anti-fouling performances of cellulose acetate(CA) ultrafiltration membranes were investigated. During the phase-inversion process, cellulose acetate was selected as a membrane forming polymer; polyethylene glycol(PEG) and polyvinyl pyrrolidone(PVP) were used as additives; acetone(Ac): N,N-Dimethylacetamide(DMAc) and N, N-Dimethylformamide(DMF) were used as solvents; and deionized(DI)water was used in the coagulation bath. All the prepared membranes were characterized in terms of hydraulic permeability(Pm), membrane resistance, average pore radius, and hydrophilicity. The top surface and crosssectional view of the prepared membranes were also observed by using field emission scanning electron microscopy. Membrane fouling and rejection experimentations were done using a stirred batch-cell filtration set-up.The experimental studies of fouling/rinsing cycles, rejection, and permeate fluxes were used to investigate the effect of PEG and PVP additives and effect of the two solvents on the fabricated membranes using bovine serum albumin(BSA) as a model protein.

Quantitative determination of PFC3D microscopic parameters

It is important to calibrate micro-parameters for applying partied flow code(PFC)to study mechanical characteristics and failure mechanism of rock materials.Uniform design method is firstly adopted to determine the microscopic parameters of parallel-bonded particle model for three-dimensional discrete element particle flow code(PFC3D).Variation ranges of microscopic of the microscopic parameters are created by analyzing the effects of microscopic parameters on macroscopic parameters(elastic modulus E,Poisson ratio v,uniaxial compressive strengthσc,and ratio of crack initial stress to uniaxial compressive strengthσci/σc)in order to obtain the actual uniform design talbe.The calculation equations of the microscopic and macroscopic parameters of rock materials can be established by the actual uniform design table and the regression analysis and thus the PFC3D microscopic parameters can be quantitatively determined.The PFC3D simulated results of the intact and pre-cracked rock specimens under uniaxial and triaxial compressions(including the macroscopic mechanical parameters,stress−strain curves and failure process)are in good agreement with experimental results,which can prove the validity of the calculation equations of microscopic and macroscopic parameters.

A fast and precise three-dimensional measurement system based on multiple parallel line lasers

This paper conducts a trade-off between efficiency and accuracy of three-dimensional(3 D)shape measurement based on the triangulation principle,and introduces a flying and precise 3 D shape measurement method based on multiple parallel line lasers.Firstly,we establish the measurement model of the multiple parallel line lasers system,and introduce the concept that multiple base planes can help to deduce the unified formula of the measurement system and are used in simplifying the process of the calibration.Then,the constraint of the line spatial frequency,which maximizes the measurement efficiency while ensuring accuracy,is determined according to the height distribution of the object.Secondly,the simulation analyzing the variation of the systemic resolution quantitatively under the circumstance of a set of specific parameters is performed,which provides a fundamental thesis for option of the four system parameters.Thirdly,for the application of the precision measurement in the industrial field,additional profiles are acquired to improve the lateral resolution by applying a motor to scan the 3 D surface.Finally,compared with the line laser,the experimental study shows that the present method of obtaining 41220 points per frame improves the measurement efficiency.Furthermore,the accuracy and the process of the calibration are advanced in comparison with the existing multiple-line laser and the structured light makes an accuracy better than 0.22 mm at a distance of 956.02 mm.

INTERNAL PRESSURE AND SOLUBILITY PARAMETER FOR LIQUIDS

Based on a modified van der Waals model, in which the excluded volume is expressed as a linear function of density, the internal pressure and the physical contribution of two - dimensional solubility parameter suggested by Bagley et al. can be expressed as functions of density and a size dependent parameter A. A group contribution method for estimating parameter A and then the solubility parameter has been developed. Average relative deviation of the predicted solubility parameters in comparison will the experimental values for more than sixty liquids including non- polar and polar species as well as those with strong hydrogen bonding is 0.8%. Further correlation with topological indices of molecules makes this method applicable to various isomers of saturated alkanes. Average relative deviation of prediction for 34 saturated alkanes is only 0.6%.

Analysis of soluble chemical transfer from soil to surface runoff and incomplete mixing parameter identification

A two-layer mathematical model proposed by Tong et al. （2010） was used to predict soluble chemical transfer from soil into surface runoff with ponded water on the soil surface. Infiltration-related incomplete mixing parameter γ and runoff-related incomplete mixing parameter a in the analytical solution of the Tong et al. （2010） model were assumed to be constant. In this study, different laboratory experimental data of soluble chemical concentration in surface runoff from initially unsaturated and saturated soils were used to identify the variables γ and a based on the analytical solution of the model. The values of γ and a without occurrence of surface runoff were constant and equal to their values at the moment when the surface runoff started. It was determined from the results that γ decreases with the increase of the ponded water depth, and when the initial volumetric water content is closer to the saturated water content, there is less variation of parameter γ after the occurrence of surface runoff. As infiltration increases, the soluble chemical concentration in surface runoff decreases. The values of parameter a range from 0 to 1 for the fine loam and sand under the controlled infiltration conditions, while it can increase to a very large value, greater than 1, for the sand under the restrained infiltration conditions, and the analytical solution of the model is not valid for experimental soil without any infiltration if a is expected to be less than or equal to 1. The soluble chemical concentrations predicted from the model with variable incomplete mixing parameters γ and α are more accurate than those from the model with constant γ and α values.

Effect of printing parameters on properties of 3D printing sand samples

Three-dimensional sand printing(3DSP)is widely applied in sand mold fabrication.In this study,the effects of printing parameters including the resolution of printehead holes,activator content,layer thickness,and recoating speed on the tensile and bending strengths,gas evolution,and loss-on-ignition(LOI)of 3DSP samples were investigated by changing single parameter,and the dimension deviation was also measured.As the resolution increases,the tensile strength,bending strength,gas evolution,LOI,and deviations at X-and Y-axis directions decrease gradually while the deviation at Z-axis direction firstly increases and then deceases.The gas evolution and LOI drops by 13.02%and 8.13%respectively,but the strength only reduces by 2.2% when the resolution increases from 0.08 mm to 0.09 mm.The strengths of samples rise at first and then decline while the gas evolution and LOI rise gradually with the increasing activator content or recoating speed.The activator content is found to have little effect on the gas evolution as the activator increases from 0.14%to 0.34%,the gas evolution is increased by 7.3%which is far less than the LOI increment of 24.1%.As the layer thickness increases,the tensile and bending strengths firstly rise and then drop while gas evolution and LOI descend.Under the optimal printing parameters of 0.09 mm resolution,0.18%activator,-10.28 mm layer thickness and 160 mm·s^(-1) recoating speed,the tensile strengths for X-sample and Y-sample are 1.48 MPa and 1.37 MPa,the bending strengths are 1.84 MPa and 1.75 MPa,the gas evolution and LOI are-19.62 mL·g^(-1) and 1.92%,respectively.

Three-Dimensional Analytical Modeling of Axial-Flux Permanent Magnet Drivers

In this paper, the axial-flux permanent magnet driver is modeledand analyzed in a simple and novel way under three-dimensional cylindricalcoordinates. The inherent three-dimensional characteristics of the deviceare comprehensively considered, and the governing equations are solved bysimplifying the boundary conditions. The axial magnetization of the sectorshapedpermanent magnets is accurately described in an algebraic form bythe parameters, which makes the physical meaning more explicit than thepurely mathematical expression in general series forms. The parameters of theBessel function are determined simply and the magnetic field distribution ofpermanent magnets and the air-gap is solved. Furthermore, the field solutionsare completely analytical, which provides convenience and satisfactoryaccuracy for modeling a series of electromagnetic performance parameters,such as the axial electromagnetic force density, axial electromagnetic force,and electromagnetic torque. The correctness and accuracy of the analyticalmodels are fully verified by three-dimensional finite element simulations and a15 kW prototype and the results of calculations, simulations, and experimentsunder three methods are highly consistent. The influence of several designparameters on magnetic field distribution and performance is studied and discussed.The results indicate that the modeling method proposed in this papercan calculate the magnetic field distribution and performance accurately andrapidly, which affords an important reference for the design and optimizationof axial-flux permanent magnet drivers.

Calculation of hydrogen solubility in molten alloys

A thermodynamic model was developed to calculate the hydrogen solubility in molten alloys based on the hydrogen solubility in constitutional pure liquid metals and their interaction parameters. The calculated results have a good agreement with the documented experimental results. The closer the molten alloy to an ideal liquid is, the more accurate the calculated results are. The compound forming ability and molar mixing heat of the constitutional elements take important roles in influencing the hydrogen solubility in molten alloys.

Solubility of the silver nitrate in supercritical carbon dioxide with ethanol and ethylene glycol as double cosolvents: Experimental determination and correlation

Solubility of the silver nitrate in the supercritical carbon dioxide containing ethanol and ethylene glycol as double cosolvents was measured under certain pressure and temperature range(10–25 MPa, 323.15–333.15 K). The impact of the pressure and temperature on the solubility was also investigated. Based on the experiment data,a correlation model concerning solid's solubility in supercritical fluids was established by combining the solubility parameter with the thermodynamic equation when a binary interaction parameter and a mixed solvent solubility parameter were defined. Experiments show the solubility of AgNO_3 increases with the pressure at a certain temperature. However, the influence of temperature is related to a pressure defined as the turnover pressure(12.3 MPa). When the pressure is higher(or lower) than this turnover pressure, silver nitrate's solubility shows increasing(or decreasing) trend as the temperature rises. Satisfactory accuracy of our presented model was revealed by comparing experimental data with calculated results.

A novel interfacial thermodynamic model for predicting solubility of nanoparticles coated by stabilizers

To improve the stability of nanoparticles in aqueous solution,polymer or surfactant,etc.are often added in solutions during the preparation process of nanoparticles,which can induce new interfaces that influence the solubility of nanoparticles.In this work,a novel interfacial thermodynamic model for describing the Gibbs energy of the nanoparticles coated by stabilizers was proposed to predict the solubility of nanoparticles.Within the developed model,the activity coefficient of nano metal system was determined by Davies model and that of nano drug system by Perturbed-Chain Statistical Associating Fluid Theory(PC-SAFT).The Gibbs energy of the interface was established as a function of molecular parameters via the application for nano metal system.Furthermore,the model was further used to predict the solubility of nano drugs itraconazole,fenofibrate,and griseofulvin.It was found that the Gibbs energy of the interface plays an important role especially when the radius of nano metal is less than 40 nm,and the developed model can predict the solubility of nano drug with high accuracy in comparison with the experimental data as well as predict the changing trend of solubility of nano drugs that increases as the particle size decreases.Meanwhile,the stabilization mechanism of stabilizers on nano drugs was studied which provided theoretical guidance for the selection of polymer or surfactant stabilizer.These findings showed that the developed model can provide a reliable prediction of the solubility of nanoparticles and help to comprehend the stabilization mechanism of the stabilizers on nano drugs with different particle sizes,which is expected to provide important information for the design of nano drugs formulations.

Physicochemical Characterization and Solubility Enhancement Studies of Mebendazole Solid Dispersions in Solvent Mixtures

Abstract： The objective was to obtain solid dispersion to improve the dissolution rate, solubility and oral absorption of MB （mebendazole）, poor water-soluble drugs. The new formulation was characterized by DSC （differential scanning calorimetry）, PXRD （powder X-ray diffraction）, FT-1R （fourier transform infrared spectroscopy） and STEM （scanning transmission electron microscopy） methods. Solid dispersions of MB with polyvinylpyrrolidone K-30 （PVP K30） were prepared by solvent evaporation method. The solubility of MB （original powder） and that of the solid dispersions was measured at 25℃ in ethanol-water. The aqueous solubility of MB was favoured by the presence of the polymer in solvent mixtures. Combination of solid dispersions with co-solvents increased the water solubility of MB in a larger extent that each method separately. Solubility parameter （o） was used to relate to solubility profiles. MB and the solid dispersions show a solubility curve with a single peak at 51 = 30.78 MPav2. Solid state characterizations indicated that the solid dispersion exist an amorphous material entrapped in polymer matrix getting highest improvement in wettability and solubility.

Maximum solid solubility of transition metals in vanadium solvent

Maximum solid solubility (C_ max) of different transition metals in metal solvent can be described by a semi-empirical equation using function Z_f that contains electronegativity difference, atomic diameter and electron concentration. The relation between C_ max and these parameters of transition metals in vanadium solvent was studied. It is shown that the relation of C_ max and function Z_f can be expressed as lnC_ max=Z_f= 7.3165- 2.7805(ΔX) 2- 71.278δ 2-0.85556n 2/3. The factor of atomic size parameter has the largest effect on the C_ max of the V binary alloy; followed by the factor of electronegativity difference; the electrons concentration has the smallest effect among the three bond parameters. Function Z_f is used for predicting the unknown C_ max of the transition metals in vanadium solvent. The results are compared with Darken-Gurry theorem, which can be deduced by the obtained function Z_f in this work.

胎盘植入孕妇子宫动脉血流动力学参数与血管新生的关系及其相关指标诊断价值

目的 探究胎盘植入孕妇子宫动脉血流动力学参数与血管新生的关系及其相关指标的诊断价值。方法 收集2016年1月至2021年4月于丹阳市人民医院常规超声检查疑似胎盘植入的125例孕妇的临床资料,根据产后最终临床诊断及病理诊断结果分为观察组(n=35,胎盘植入)与对照组(n=90,非胎盘植入)。比较两组孕妇的临床特征、子宫动脉血流动力学参数[子宫动脉搏动指数(PI)、阻力指数(RI)、收缩期峰值血流速度与舒张末期血流速度的比值(S/D)]及血管新生指标[可溶性血管内皮生长因子受体-1(sFlt-1)、血管内皮生长因子(VEGF)]。分析子宫动脉血流动力学参数、血管新生指标与胎盘植入的关系,子宫动脉血流动力学参数对胎盘植入的诊断价值,以及子宫动脉血流动力学参数与血管新生指标的相关性。结果 观察组孕妇的流产次数、剖宫产次数均明显多于对照组孕妇,PI、RI及sFlt-1水平均明显低于对照组孕妇,S/D、VEGF水平均明显高于对照组孕妇,差异均有统计学意义(P<0.01)。多因素分析结果显示,调整混杂因素流产次数、剖宫产次数后,PI、RI、S/D、VEGF、sFlt-1均仍为胎盘植入的独立影响因素(P<0.05)。受试者工作特征(ROC)曲线分析结果显示,PI、RI、S/D、VEGF、sFlt-1诊断胎盘植入的曲线下面积(AUC)分别为0.716、0.717、0.626、0.797、0.793,各指标联合诊断胎盘植入的AUC为0.870。胎盘植入孕妇子宫动脉血流动力学参数PI、RI与VEGF呈负相关,与sFlt-1呈正相关(P<0.05);S/D与VEGF呈正相关,与sFlt-1呈负相关(P<0.05)。结论 胎盘植入孕妇彩色多普勒超声下的子宫动脉血流动力学参数与血管新生具有明显相关性,且临床监测子宫动脉血流动力学参数、血管新生指标对胎盘植入的诊断具有积极意义。