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This paper presents validation of a particle impact breakage model i.e. Vogel and Peukert model with a focus on the impact number. The Vogel and Peukert model developed based on mechanical and statistical foundation has been widely used in various fields such as mineral engineering and chemical engineering but is barely studied in the application of repeated impact. The selective breakage data in the literature is collected to provide the database for model validation. It has shown that the Vogel and Peukert model is generally applicable to all the breakage cases considering the impact number. The effect of impact number is further elaborated in the population balance model (PBM) whereas the particle dynamics are provided from Discrete Element Method (DEM) simulation of an impact pin mill. The global system analysis of impact number is carried out with the synergic effect from impact velocity. The successful validation of Vogel and Peukert model incorporating the effect of impact number demonstrates its versatility whilst other key parameters such as impact energy and particle size can be considered in parallel.

This paper presents a thorough study of particle impact breakage in selection function with a unified breakage criterion. The impact mode and breakage pattern for particulate materials are classified based on a significant review of well-established impact testers. It was found that the lack of a unified breakage criterion to determine the breakage probability disables a direct comparison of particle breakage propensity from different impact loading testers. The literature breakage models to describe the breakage probability are reviewed where the advantage and drawback of these models are scrutinized. The sourced literature breakage models are compared with the zeolite breakage datasets in a unified breakage criterion to evaluate the model performance. A novel computational modelling workflow for a milling process is proposed to provide a guidance in implementing the digital twin in milling process prediction. The breakage probability models, i.e. the selection functions are comprehensively assessed in population balance model to examine the model serviceability. The model simplicity and fidelity in the model assessment are specifically discussed and the value of digital twin in substantially reducing the experimental trials is highlighted.

This paper presents a breakage model of particulate solids under impact loading based on a mechanical approach. Existing breakage models are assessed using the experimental data from single particle impact tests, indicating a more general breakage model is required. Indentation fracture mechanics is used to account for surface damage under dynamic loading. The effect of impact angle is considered in the model, which rationalizes the contributions of both the normal and tangential impact velocity. A unified curve of breakage propensity is constructed using the equivalent velocity under oblique impact based on the experimental data from this study and the literature. This model provides a basis to evaluate breakage propensity of brittle/semi-brittle particles subject to oblique impact and the proposed equivalent velocity has a potential to improve the description of impact energy spectra for milling processes where oblique impact of particle is common and typically ignored.

This paper presents a scale-up procedure of parameter estimation in the selection function and breakage function from single particle impact breakage to inform the predictions at the process scale of an impact pin mill. The selection and breakage functions used in population balance model (PBM) for particle breakage in the literature are briefly reviewed. Single particle breakage tests are conducted in a vertical impact tester subject to varying impact velocities. The single particle breakage results further serve to provide the database for the parameter estimation in Vogel and Peukert model (Vogel and Peukert, 2005). The estimated parameters in the particle level are upscaled in an impact pin mill using the population balance model, which is implemented in the software gPROMS (Process Systems Enterprise, UK) (gPROMS® 4.1 Release Notes, 2016). The impact milling tests were carried out in an impact pin mill UPZ100 subject to four feed rates, providing the dataset for model validation. The sensitivity analysis of the PBM parameters was conducted to help identify their leverage on the particle size distribution. The scale-up procedure by specifying the parameters from single particle level to the process level of PBM demonstrates an approach to help predict the size reduction process subject to the prevailing mechanism in an impact pin mill and other milling processes alike.

Despite many attempts to establish material grindability in a milling process, it remains very difficult to predict the milling performance. In this study, impact milling tests were carried out under varying operational conditions in a UPZ100 impact pin mill. The product size distribution and fineness of milled alumina particle are reported and analyzed. A multiscale framework coupling discrete element method (DEM) and population balance model (PBM) is proposed to predict the milling performance of the mill. The impact velocity and impact frequency information from DEM is utilized to inform the mill operation parameters of the PBM model at the process scale, whilst the material grindability parameters are evaluated using constrained optimization to match a milling test. The predictions of the product size distribution show very good agreement with the experimental results. This indicates that the multiscale model is promising for optimizing the design and operation of mills.

This paper presents a novel breakage kernel for use in population balance modelling for twin screw granulation (TSG) using mechanistic understanding in different screw elements. Breakage-isolated experiments are conducted using conveying and distributive mixing elements for a range of model formulations of widely different yield stresses. The breakage kernel, i.e. the selection and breakage functions, are mathematically formed based on the identification of the dominant breakage mechanisms of chipping and fragmentation in the conveying and distributive mixing elements, respectively, and the unique geometries of the two screw elements. A parametric study for the proposed breakage kernel is performed to identify the influential parameters on the breakage kernel. This is the first breakage model specifically developed for a TSG and incorporates a mechanistic understanding of several key parameters, particularly the role of screw geometry. The breakage model is well suited to population balance modelling framework for model-driven design of twin screw granulation.

To review the therapeutic effect of acupuncture and moxibustion on allergic rhinitis based on the network Meta-analysis.The randomized controlled trials of acupuncture and moxibustion for allergic rhinitis were retrieved from the databases, starting from the date of establishment to August 17, 2020, i.e. the PubMed, EMbase, Cochrane Library, CNKI, Wanfang and VIP. The traditional Meta-analysis and network Meta-analysis were performed by RevMan5.3 and GeMTC0.14.3.A total of 50 RCTs were included, including 4260 patients, involving 5 kinds of acupuncture and moxibustion therapies, such as acupuncture, moxibustion, acupoint application, acupoint thread-embedding and auricular point therapy.①In term of total effective rate, acupuncture, moxibustion and acupoint thread-embedding were superior to western medication and auricular point therapy (The therapeutic effect of acupuncture and moxibustion on allergic rhinitis is better than western medication, and acupoint thread-embedding has the best curative effect.

Saline soil has imposed a serious threat on many expressway engineering and agricultural areas. This paper describes the performance of saline soil treatment using electrokinetic remediation technology. Comparison study involving sample soil and in situ soil is carried out. Two different electric fields, i.e., uniform and non-uniform are utilized to promote the migration of inorganic ions contained in the soil toward the electrode area. The effects of different electric field types and potential gradient ion migration rate in soil are investigated. The test result reveals that a uniform electric field of a constant potential gradient of 1 V/cm drives the Cl− through the sample soil at a rate of 1.36 cm/h. Moreover, larger potential gradients could make ions migrate faster, but more electrical energy is consumed in such a way. Compared with uniform electric field, the non-uniform process maintains the soil pH values more effectively and consumes less electrical energy. A desirable result of removing Na+ in soil is expected using electrokinetic remediation technology under four-times scaling up of soil volume.

This study explored variations in the rhizosphere microbial community composition resulting from the continuous cropping of sorghum. We explored the potential growth-promoting effects of Bacillus amyloliquefaciens in manipulating the microbial community composition of the rhizosphere soil under continuous cropping. Illumina MiSeq sequencing was used to compare the composition of the bacterial and fungal communities in the rhizosphere soil from a sorghum–maize rotation system, sorghum continuous cropping system, and sorghum continuous cropping with the application of the biological agent B. amyloliquefaciens. The rhizosphere soil under continuous sorghum cropping had lower bacterial richness and higher fungal diversity than the sorghum–maize rotation rhizosphere soil. The bacterial phyla Acidobacteria and Gemmatimonadetes, and the fungal phylum Basidiomycota, were strongly enriched in the continuous cropping soil. The class Tremellomycetes was the most dominant group, accounting for 19.30% of the total fungal sequences in the continuous cropping soil and 4.51% in sorghum-maize rotation soil. Application of B. amyloliquefaciens significantly decreased the abundance of Tremellomycetes by 8.87% in the continuous cropping soil. Our results indicate that the decrease in sorghum growth and yield under continuous cropping are in coincidence with the alteration of soil microbial community composition, particularly the accumulation of Tremellomycetes in the continuously cropped rhizosphere soil. Our findings contribute to an improved understanding of the effects of continuous sorghum cropping on soil microbiome, and B. amyloliquefaciens can be used to manipulate the microbial communities of the sorghum rhizosphere soil.

Permeability is a key parameter to describe fluid transport properties of porous medium; however, the permeability measurement is extremely difficult for tight porous medium, e.g. fine-grained rock or dense soil. In this paper, three methods for gas permeability measurement, i.e. steady state method, pulse decay method (PDM) and pressure oscillation method (POM), are first reviewed and then their advantages and drawbacks are discussed. Both analytical and numerical solutions of gas permeability are presented for the tight porous medium. The results show that the analytical method is relatively simple but only valid under certain conditions, whilst the numerical method is more robust and generic, which can take into account several factors such as porosity, saturation, gas leakage, and unconventional boundary conditions. The influence of the effective porosity on the permeability determination is further analyzed using the proposed numerical method. In this study, new pressure data interpretation procedures for PDM and POM are proposed, and the obtained results can serve as a guidance to define a proper method for permeability measurement of the tight porous medium. Keywords: Permeability measurement, Steady state method, Pulse decay method (PDM), Pressure oscillation method (POM), Effective porosity, Tight porous medium

It is inevitable that adverse conditions such as layered strata, groundwater, and ground overload will be encountered during the excavation of shallow tunnels. However, analytical theories on shallow tunnel stability are not well investigated while taking above factors into consideration together. In this paper, a shallow tunnel in two-layer rock strata is taken as an example. The influences of the groundwater table, ground overload, supporting force, etc., are considered. The corresponding kinematically admissible velocity fields for roof collapse under two cases are established. The analytical solutions of the curvilinear equations for failure of the roof surrounding rock masses and the critical burial depth of the shallow tunnel in Case I and Case II are obtained, respectively, based on upper bound theorem and variational principle. In addition, the influencing regularities of the roof collapse mechanisms under differing mechanical parameters are analyzed. It was found that the roof collapse range increases when the groundwater table drops or the supporting force, rock empirical parameter A, compressive strength, or tensile strength increase. Conversely, the roof collapse range decreases when the thickness of the upper stratum, pore water pressure coefficient, ground overload, rock empirical parameter B, or unit weight increase. The collapse range indicates the safety state of the tunnel roof. The larger the range is, the more external force power is required to generate collapse and the safer the roof is. Practically, it is efficient to improve the roof stability of the shallow tunnel by increasing the supporting force or employing the grouting technique to increase rock empirical parameter A and other strength parameters.

This paper presents a flowsheet modelling of an integrated twin screw granulation (TSG) and fluid bed dryer (FBD) process using a Model Driven Design (MDD) approach. The MDD approach is featured by appropriate process models and efficient model calibration workflow to ensure the product quality. The design space exploration is driven by the physics of the process instead of extensive experimental trials. By means of MDD, the mechanistic-based process kernels are first defined for the TSG and FBD processes. With the awareness of the underlying physics, the complementary experiments are carried out with relevance to the kinetic parameters in the defined models. As a result, the experiments are specifically purposeful for model calibration and validation. The L/S ratio (liquid to solid ratio) and inlet air temperature are selected as the Critical Process Parameters (CPPs) in TSG and FBD for model validation, respectively. Global System Analysis (GSA) is further performed to assess the uncertainty of CPPs imposed on the Critical Quality Attributes (CQAs), which provides significant insights to the exploration of the design space considering both TSG and FBD process parameters.

Particle aggregation and breakage phenomena are widely found in various industries such as chemical, agricultural and pharmaceutical processes. In this study, a physics-informed neural network is developed for solving both the forward and inverse problems of particle aggregation and breakage processes. In this method, the population balance equation is directly embedded in the loss function of a neural network so that the network can be trained efficiently and fulfil physical constraints. For the forward problems, solutions of population balance equations are obtained through the optimization of the neural network where the predictions well match the analytical solutions. In the inverse modelling, the data-driven discovery of model parameters of population balance equations is investigated. The sensitivity regarding the selection of different neural network structures is also investigated. The developed population balance equations embedded with neural network approach is promising for solving inverse problems of particle aggregation and breakage processes with noisy observation data.

A multiscale modelling approach to integrate resultful information of particle breakage at distinct scales is presented for quantitative prediction of a milling process. The nanoindentation test of zeolite particles is carried out to provide the deterministic value of mechanical properties, prior to which the Hertz based contact theory is described. The impact pin milling test is made to measure the particle size distribution subject to three rotary speeds. The population balance model composed of selection function and breakage function is developed to predict the varying milling operations based on successful model validation. With the hybrid of theoretical, experimental and numerical avenues, a conceptual multiscale modelling roadmap with complementary strength is proposed. The best available information spanning distinct scales is scoped where the interaction of physical twin and digital twin is highlighted. Global system analysis of the key parameters provides projected confidence in milling performance beyond the existing experimental space.

Water inrush is one of the most serious threats to the construction safety of karst tunnels. Numerical simulation is one of the important means of underground engineering research, which i...

This paper presents a comprehensive assessment of the most widely used tablet compaction models in a continuous wet granulation tableting process. The porosity models, tensile strength models and lubricant models are reviewed from the literature and classified based on their formulations i.e. empirical or theoretical and applications, i.e. batch or continuous. The majority of these models are empirical and were initially developed for batch tabletting process. To ascertain their effectiveness and serviceability in the continuous tableting process, a continuous powder processing line of Diamond Pilot Plant (DiPP) installed at The University of Sheffield was used to provide the quantitative data for tablet model assessment. Magnesium stearate (MgSt) is used as a lubricant to investigate its influence on the tensile strength. Whilst satisfactory predictions from the tablet models can be produced, a compromise between the model fidelity and model simplicity needs to be made for a suitable model selection. The Sonnergaard model outperforms amongst the porosity models whilst the Reynolds model produces the best goodness of fitting for two parameters fitting porosity models. An improved tensile strength model is proposed to consider the influence of powder size and porosity in the continuous tableting process.

A comprehensive mesoscopic investigation has been conducted to examine the evolution of the fracture process zone (FPZ), using notched plain concrete beams subjected to three-point bending as a generic representation. The concrete beams are modelled as random heterogeneous materials containing three components, namely coarse aggregates, mortar and the interface transition zone (ITZ). To better represent the fracture process in concrete, a coupled cohesive-contact interface approach is employed to model the crack initiation, crack propagation and the friction mechanisms during the fracture process. Thus, the FPZ is naturally captured in the simulation as the zone composed by microcracks along the ITZ or through the mortar matrix in the mesoscale model. The macroscopic response of load-deformation curves as well as the shapes and sizes of FPZ calculated from numerical results are validated against experimental observations and good agreement is achieved. Subsequent modelling results demonstrate that the FPZ tend to exhibit a main crack and multiple secondary microcracks. During the growth of the main crack, new microcracks initiate while some microcracks formed earlier stop growing and even close. The evolution path of the FPZ is strongly irregular due to the random spatial distribution of the aggregate particles with weak ITZs. The influence of the size effect on the FPZ is also investigated from the numerical simulation. Results show that the width of the FPZ is insensitive to the beam size but the length of the FPZ is strongly dependent on the beam size, and such characteristics of the FPZ are deemed to be intrinsic reasons for the overall size effect phenomenon in concrete structures.

This paper presents a generic framework of Model Driven Design (MDD) with its application for a twin screw granulation process using a mechanistic-based population balance model (PBM). The process kernels including nucleation, breakage, layering and consolidation are defined in the PBM. A recently developed breakage kernel is used with key physics incorporated in the model formulation. Prior to granulation experiments, sensitivity analysis of PBM parameters is performed to investigate the variation of model outputs given the input parameter variance. The significance of liquid to solid ratio (L/S ratio), nucleation and breakage parameters is identified by sensitivity analysis. The sensitivity analysis dramatically reduces the number of fitting parameters in PBM and only nine granulation experiments are required for model calibration and validation. A model validation flowchart is proposed to elucidate the evolution of kinetic rate parameters associated with L/S ratio and screw element geometry. The presented MDD framework for sensitivity analysis, parameter estimation, model verification and validation can be generalized and applied for any particulate process.

Rhizosphere microbiota play a pivotal role in promoting plant growth and defending against pathogens, but their responses to abiotic environmental stress remain largely elusive. Here, we investigated the influences of low-N stress on rhizosphere bacteria of six sorghum cultivars in a glasshouse experiment. The alpha diversity of bacteria (as revealed by Shannon diversity and Chao1 richness indices) was remarkably lower in rhizosphere soils than in bulk soils, and was significantly higher under low-N stress than under N addition. Principal coordinates analysis revealed that the bacterial community compositions in rhizosphere soils were clearly separated from bulk soils, and the rhizosphere soils under low-N stress or with N fertilization were clearly separated, indicating that both rhizosphere effects and N fertilization impacted the rhizosphere bacterial community. Notably, the relative abundances of beneficial bacteria such as Bacillaceae and Streptomycetaceae significantly increased in rhizosphere soils under low-N stress, which had significantly positive correlations with the sorghum N uptake. The relative abundance of Nitrosomonadaceae in rhizosphere soils was significantly lower than that in bulk soils, while the relative abundance of Rhizobiaceae showed an opposite pattern. Taken together, our results suggested that sorghum rhizosphere effects can reduce soil bacterial diversity possibly through recruiting specific bacterial species under low N stress.

This paper aims to establish a breakage master curve of oblique impact using a DEM bonded contact model. Despite numerous advantages of particle impact breakage by DEM, there exist two major issues in hindering the distinct power of DEM with a fully predictive capacity. The first barrier is the notable discrepancy of breakage probability evaluation, i.e. breakage ratio in experiments and damage ratio in DEM. The second barrier is the lack of an oblique impact model where the breakage probability subject to various impact angles can be unified. In this work, these two longstanding barriers are addressed by conducting digital twin of impact breakage using a DEM bonded contact model. A newly developed oblique impact model is used to account for the effect of impact angle. The equivalent velocity proposed in the oblique impact model is shown to successfully establish a remarkable breakage master curve for all the impact angles.

The modelling of fracture initiation and propagation is a nontrivial problem in computational mechanics. However, it is an area that is extremely important in engineering applications, requiring accurate and robust numerical methods that can be applied to a variety of materials. This paper presents the development of a new numerical modelling approach, which combines material, or configurational, forces and the material point method (MPM), for finite deformation crack modelling of linear elastic solids in two dimensions. The combination of these numerical methods offers a number of advantages relating to the flexibility of the MPM in terms of decoupling the material deformation from the computational grid and the general nature of configurational force theory in terms of being applicable across different material behaviour. In the method presented in this paper, the MPM forms the basis of the mechanical response of the underlying material, while the configurational force theory provides a fracture criterion for crack modelling through a post-processing procedure. The developed modelling framework is applied to a number of benchmark problems for linear elastic solids in 2D. All simulations show good agreement with the results in the literature, which demonstrates that the combined configuration force-material point framework is a promising numerical tool for fracture modelling.

Wet granulation is a critical unit operation in solid dosage form manufacturing in the pharmaceutical industry. Traditionally, wet granulation has been a batch process. Recently, there has been a move toward more advanced manufacturing approaches such as continuous processing to allow more rigorous process control, consistent quality assurance, and reduced capital costs. This chapter discusses continuous wet granulation process with emphasis on twin screw granulation as the most commonly used continuous granulation approach in the pharmaceutical industry. The key design features of a twin screw granulator (TSG) are described, and comparisons with batch high shear granulation equipment are made. The effects of formulation and process variables on granule attributes are discussed. Mechanistic studies of screw elements with the proposed granulation rate processes are presented. Real-time process monitoring tools, including spectroscopic and imaging techniques, are described. Implementation of dimensional analysis as a tool for scaling up/scaling out of continuous twin screw granulation is presented. Two numerical methods, that is, population balance model (PBM) and discrete element method (DEM), are chosen for the multiscale modeling of twin screw granulation, and their coupling mechanisms of data exchange between DEM and PBM are discussed.

In the present study, microalgal biomass (Anabeana circinalis and Scenedesmus quadricauda) was used as biofertilizer in cucumber cultivation. The response of cucumber growth characters to microalgal biofertilizer was evaluated. Moreover, rhizosphere microbial diversity and community composition of cucumber was analyzed through 16S rRNA high-throughput Illumina sequencing data. The results showed that microalgal biomass as biofertilizer significantly promoted height, number of leaves and flower buds, and stem diameter of cucumber. The application of a high concentration of S. quadricauda to soil raised the diversity of rhizosphere fungi of cucumber. The rhizosphere microbial community of cucumber also responded to microalgal biofertilizer. The most abundant bacterial phylum in all samples was Proteobacteria. Acidobacteria, Actinobacteria, and Gemmatimonadetes were also highly abundant in all samples. Ascomycota was the most predominant fungal phylum in all samples. Zygomycota was the dominant phylum in the control, whereas Basidiomycota was dominant in all treatments. At the genus level, both growth-promoting bacteria and fungi (Azotobacter, Bacillus, Pseudomonas, Cryptococcus, Fusarium, Penicillium, and Trichoderma) from the rhizosphere of cucumber were enhanced in all treatments after the application of microalgae fertilizer. All results indicate a significant impact of microalgal biofertilizer on the growth of cucumber and microbial abundance in the cucumber rhizosphere.

Splitting failure, which is recognized as a special engineering geology phenomenon, occurs continually in the brittle rock mass of caverns during underground excavation. In this paper, a splitting model of linear slippage crack groups is built with fracture mechanics, energy analysis, and crack extension theories. Considering intrinsic cracks in rock mass and change of outer stress, intrinsic cracks propagate into macroscopical splitting cracks that are approximately parallel to the side wall of caverns. The splitting criterion of cavern rock mass and the method for predicting displacement in view of splitting opening displacement are proposed. In the end, the forecasting method is applied to the Jinping-I Hydropower Station, underground caverns engineering in China, the splitting failure zone and forecasting displacement are accordant with the monitoring data. The new forecasting displacement method is proven to contribute to the construction of similar underground caverns.

In order to analyze the stability of surrounding rocks with two groups parallel joints under different angles, a new method, DDARF (discontinuous deformation analysis for rock failure) program was adopted to investigate three cases of uniaxial compression tests of two groups parallel joints sample with the angels 30, 45 and 60. The results show the sample with 30 is least prone to be destroyed and the sample with 60 are most likely to be destroyed. Then DDARF program was also applied to investigate the underground cavern excavation process of two groups parallel joints surrounding rocks with the angels 30, 45 and 60. The results show that the stability of underground cavern with joint angel of 60 is worst in the aspect of stability.

The height of the water-conducting zone is of significant importance for the safety of underground mining under a water body. Fully backfilling a mine excavation with gangue provides the advantages of safety and efficiency during the extraction of coal under buildings, railways and water bodies. Based on a mine with steeply dipping coal seams, a systematic numerical study of the damage mode of the safety pillar and roof strata surrounding a stope with and without backfilling was performed. The fracture initiation, propagation and coalescence in the stressed strata, and the seepage fluid field evolution were numerically obtained during the advance of the working face, which provided the detailed evolution of the fracture zone and the interaction of the fractures surrounding the stope in the steeply inclined coal seam. When backfilling with gangue is used as part of the mining process, the degree and absolute values of roof strata deformation are clearly reduced. The safety of the pillar and roof strata are...

The study examined the wear resistance of Al2O3/epoxy resin composite coating including the composite curing agents and its ratio,fillers volume fraction and its particle size.The results show that, firstly, when the low molecular polyamide and phenolic amine composite curing agent were added into the epoxy resin system within a proper ratio ,it can improve the coating wear resistance property, especially the quality ratio is 1:1. Secondly, when the fillers particle size is fixed, its volume fraction ranges from 0 to 36.8%, when the volume fraction is 23.4%, the wear resistance property is better. Thirdly, when the fillers volume fraction is fixed, its particle size ranges from 28μm to 106μm, when the size within the range of 58-75μm, it can significantly improve the wear resistance ,the best wear resistance is about 3 or 5 times of the basal material Q235,having a higher cost performance. Besides, the coating resistance mechanism was investigated.

Al2O3-glaze composite ceramic coating was prepared with enamel coating as transition layer and Al2O3 as hard antiwear facies on Q235A steel surface in this paper, and the effects of the particle size and volume fraction of ceramic coating on erosive wear behavior of composite coating were investigated. The results show that enamel performance of ceramic coating is better when the particle size of glaze is 16µm; the anti-wear property of composite ceramic coating is improved by adding Al2O3 particle, and the coating with 50μm particle size and 40% volume fraction particles, eroded at 45° impact angle at 15MPa pressure, is the best, which is 4.2 times than that of the enamel coating without Al2O3.

A new type of pellet binder was prepared with oxalic acid as sodium silicate chemical modification agent in this paper, the compressive strength of which improved obviously. It improved from 0.6 KN/a to 2.4 KN/a, when the amount of oxalic acid is 8%. Meanwhile, carboxyl introduced at 390°C started carbonization decomposition, and pelletizing properties wouldn't be affected without new pellet impurity. The analysis shows that adding oxalic acid introduces carboxyl only in the binder, but doesn't generate new functional groups; Polymer layer formed by carboxyl adsorption on sodium silicate gel particle surface limits colloidal particle growing up, and plays roles of refining colloidal particle and improving the bonding strength.

In this paper, two-component compound modifiers were used to modify sodium silicate, preparing a new type of inorganic-organic composite cold pellet binder consolidation. The dispersion of its formative adhesive films is good and the bonding ability is also high. By changing modifier ratio and addition, the information of pellet structure and composition was studied. The results showed that: when the compound modifier-component mass ratio is 1:1, adding the amount is 2%, the modified adhesive bond strength is higher, the production of pellets using compression strength up to 2.75KN / a, meeting the needs of blast furnace smelting.

The influence of added quantity of SiO2 micro-powder on ceramic core properties was investigated in this paper. The results show that, the quantity of added SiO2 powder has significant effect on the properties of ceramic core, and the room temperature flexural strength of ceramic core samples, sintered at 1550°C for 4~5 hours' holding time, increases with the increasing quantity of SiO2. The room temperature flexural strength can reach 35MPa, when the amount of SiO2 powder is 15%. The XRD results show that new mullite phase was detected in the composite material, and that is the key factor that helps to increase the strength.

Al2O3/epoxy resin composite materials were prepared with alumina as filler in this paper, and the effects of particle size and added quantity of Al2O3 powers on the thermal conductivity of the composites have been investigated. The results show that, thermal conductivity of the composites increases with the increase of the added quantity of Al2O3 powders, and suitable particle size of alumina filler could help to form heat conductive chain which can improve the thermal conductivity of the composites effectively. The thermal conductivity could reach 0.48 W/(m•K), which is five times than that of pure epoxy resin, when the amount of alumina powders is 60% and its mean particle size is 100µm.

The roasting process of leachable alumina based ceramic core has been systematically studied in this paper, the results show that, the roasting process should be divided into two parts, i.e., dewaxing process and sintering process, and the plasticizer can be removed completely from the ceramic green body by the dewaxing process with little residue left behind. The sintering temperature and mineralizer are the decisive factors to ensure the strength of ceramic core. The apparent porosity of ceramic core will decrease obviously while the room temperature flexural strength will increase when the sintering temperature is rising. The room temperature flexural strength can exceed 14MPa when the ceramic core samples sintered at 1550°C. The ceramic core samples will present excellent comprehensive properties when the sintering temperature is 1550°C and the added quantity of SiO2 is 8~10%, i.e., apparent porosity is 44.7~46.9%, bulk density is 1.93~1.99 g/cm3, room temperature flexural strength is 10.65~11.93MPa.

The anchorage force loss of the prestressed anchor rope results in reduction or loss of anchorage force, which poses an enormous threat to the project safety. In the conceptual design process, factors like the system , structure, spacing and tonnage of anchorage, and properties of rock and soil should be considered and measures should be taken to effectively control or reduce the effect of the anchorage force loss, which possesses great theoretical and practical significance on the design, construction , safety and social-economic benefits of the anchorage project. Finally, the validity and reliability of design measure was proved by an engineering example.

The traditional method to remove zinc coating from matrix has some problems, such as complicated process, expensive cost, and environmental pollution problems. In our article, mechanical method is proposed to remove zinc from galvanized sheet. Using this method, In the paper, the galvanized sheet can reused by an easy and low-cost method. The paper mainly introduces the technological process, best choice of abrasive material and analysis of the results. Under laboratory conditions, this study has achieved some achievements, which has some guiding significance for removing abandoned tobacco zinc coating in future practical production.

Radar absorbing structures (RAS) can’t only load bearing but also absorb electromagnetic wave energy by inducing dielectric loss and minimizing reflected electromagnetic waves. Therefore, the development of the RAS haves become important to reduce RCS of the object. These composites possess excellent specific stiffness and strength. The electromagnetic wave properties of RAS can be effectively tailored by controlling the content of the lossy materials. Radar absorbing structures composed of glass fibers, carbon fibers and epoxy resin filling with carbon nanotubes (CNTs), was designed and prepared. Permittivity of the composite was measured by using a network analyzer, HP8510B. The contents of composites were observed to be different from each composite. Reflection of electromagnetic waves energy of RAS was calculated by using the genetic algorithm, it was discovered that the composites can be applied to design an optional RAS composites filling with CNTs.

Inbetween the many factors, which will influence the distribution character of initial stress in a mountain, different angle of mountain slopes and horizontal geostress will have important effects on it. Therefore, stress distribution in mountains under different slope angles with considering different lateral coefficients of initial stress is studied using numerical method in here. In this paper, the initial geostress distribution of mountain at typical vertical profiles are studied in the gravity field, with the slope angles being 30°, 45° and 60°, respectively. After the calculation, it can be known that the actual initial vertical stresses may be 2-5 times of the gravitational stresses calculated by direct depth gh for some zones. Meanwhile, it reveals that different horizontal geostress has a momentous impact on it as well. Computation of damage-fracture model for jointed rock is adopted to analyze the rock stability of a cavern. Comparison of the rock stability excavated in a mountain area or under a flat surface is made also.

As source of ceramic core, the raw materials play an important role in determining the properties of ceramic core. In this paper, the effect of matrix Al2O3 particle size on the properties of ceramic core during fabricating is mainly studied and discussed, the test results show that reasonable particle size match of coarser, middle and finer matrix Al2O3 will be beneficial for properties of ceramic core. Matrix Al2O3 powders with double peak or multi-peak can form denser packing and help to increase the ceramic core’s strength than powders with single peak can. The influence of middle Al2O3 particle size is great for its large proportion in matrix materials, and its optimal particle size range is between 23~28µm.

The reasonable selection of a location for underground structures has a great influence on the stability of surrounding rock masses, especially when the construction is built in the alpine and gorge regions. In general, the higher and steeper the mountains are, the more significant the effect is. In this paper, numerical analysis was carried out to study the stress distribution characters in the mountain with different slope angles of 30 °, 45 ° and 60 °. The results show that, the initial vertical component of stress field can not be directly determined by the buried depth when the slope angle is greater than 30 °. Meanwhile, numerical results indicate that is unfavorable for the structural stability when the underground caverns are constructed in the stress concentration areas of mountains with high slope angle. Moreover, some conclusions and recommendations were proposed for the design of underground constructions.

WO3 and Ti-doped WO3 electrochromic films were prepared by mid-frequency dual-target magnetron sputtering method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and spectrophotometer were used to characterize the structure, morphology, composition and transmittance properties of the films, respectively. The results show that this method is available to deposit WO3 and Ti-doped WO3 electrochromic films. The as-deposited films prepared at room temperature are amorphous and display good transmittance. The difference value of transmittance between the bleached and coloration states of WO3 film is above 60% at 633nm. Ti-doped WO3 films have smoother surface and smaller grains than undoped ones. Moreover, the crystalline temperature increases after doping titanium, because the titanium atoms influence the lattice distortion of the WO3 films. So it is more convenient for Li+ ions to inject into films and can enhance the response speed and stability of Ti-doped WO3 electrochromic films.

The stability of underground cavities is of increasing importance considering the predominant cavity locations built up in high mountain and canyon environments. Such cavity locations are characterized by a high initial in situ stress, which results in brittle fracture and deformation of the surrounding rock during cavity construction. This paper presents a numerical study of underground cavern stability considering four factors, namely, mechanical property of surrounding rock, cavern burial depth, lateral pressure coefficient in horizontal direction, and the angle included between plant longitudinal axis and horizontal principal stress. Analytical methods including the key point displacement in side wall, plastic zone volume, and splitting fracture volume are used to characterize the stability of underground cavern. A modified formula to predict side wall displacement is proposed based on prior work, which is applicable to 3D computation model by taking horizontal geostress in two directions into account. Eventually, the optimal layout of underground cavern is put forward under different conditions of geostress field.

Amorphous WO3 films were prepared by mid-frequency dual-target magnetron sputtering. X-ray diffraction, energy dispersive X-ray microanalysis, scanning electron microscopy and spectrophotometer were used to characterize their structure, morphology, composition and transmittance properties. The effects of oxygen content and heat treatment temperature on the electrochromism were studied. The results show that the as-deposited films are amorphous. WO3 crystalline is formed when annealing temperature is up to 300–400 °C. The films deposited at higher oxygen content show a good electrochromic property after annealing at 200 °C.

The reaction of Cp2TiCl2 with o-mercaptophenolate in the presence of a base (Et3N or NaOMe) afforded the complex (BnMe3N)2[Ti(o-SC6H4O)3] or (Et4N)2[Ti2(o-SC6H4O)4(OMe)2]·2H2O under slightly varied conditions. Single-crystal X-ray diffraction studies showed that the Ti(IV) geometry in both complexes is a severely distorted octahedron with average trans-angles of 162.2° and 159.1(2)°, respectively. Crystallographic data for (BnMe3N)2[Ti(o-SC6H4O)3]: a = 9.884(3), b = 16.501(7), c = 23.028(7) A; β = 99.89(3)°, V = 3700.2(22) A3, Z = 4, final R = 0.050 for 3134 observed reflections; for (Et4N)2[Ti2(o-SC6H4O)4(OMe)2]·2H2O: a = 8.953(4), b = 10.148(3), c = 14.527(3) A; α = 73.16(2)°, β = 73.00(3)°, γ = 83.56(4)°, V = 1207.4(9) A3, Z = 1, final R = 0.082 for 2233 observed reflections. The isolation of (BnMe3N)2[Ti(o-SC6H4O)3] provides strong evidence for the synthon character of [Ti(mp)3]2−, which was previously predicted to be present in the complex (Et4N)2[Ti(mp)3Na(MeOH)2]2. Both electronic and 1H NMR spectr...

A nickel(II) complex of the pyridine-2-aldehyde Schiff base of S-methyldithiocarbazate (HNNS) has been synthesized and characterized by means of elemental analysis, IR and UV-vis spectra. The crystal structure of the complex has been determined by single-crystal X-ray diffraction. The complex crystallizes in the monoclinic, space P21/c, with a = 14.092(2), b = 16.886(2), c = 8.857(2)A; β = 105.78(3) °, V = 2028.2(6) A3, and Z = 4. The nickel atom is octahedrally coordinated by two uninegatively charged tridentate Schiff base in a mer-configuration via the pyridine nitrogen atom, azomethine nitrogen atom, and mecaptide sulfur atom.