Adsorption is one of the widely used processes in the chemical industry environmental application. As compared to mathematical models proposed to describe batch adsorption in terms of isotherm and kinetic behavior, insufficient models are available to describe and predict fixed-bed or column adsorption, though the latter one is the main option in practical application. The present review first provides a brief summary on basic concepts and mathematic models to describe the mass transfer and isotherm behavior of batch adsorption, which dominate the column adsorption behavior in nature. Afterwards, the widely used models developed to predict the breakthrough curve, i.e., the general rate models, linear driving force (LDF) model, wave propagation theory model, constant pattern model, Clark model, Thomas model, Bohart-Adams model, Yoon-Nelson model, Wang model, Wolborska model, and modified dose-response model, are briefly introduced from the mechanism and mathematical viewpoint. Their basic characteristics, including the advantages and inherit shortcomings, are also discussed. This review could help those interested in column adsorption to reasonably choose or develop an accurate and convenient model for their study and practical application.

The purpose of this research is to investigate the potential of pre-treatment with phosphoric acid (PA) and monobasic calcium phosphate (MCP) for the stabilization of heavy metals in sludge and its bottom ash. The tannery sludge samples were collected in Wenzhou, China and heavily contaminated with heavy metals, such as Pb, Cr and so on. The samples were pre-treated with PA or MCP. Then XRD and TCLP tests were adopted as the evaluating methods to characterize the Pb, Cr, Cu, Zn and Cd immobilization in the pre-treated sludge and its bottom ash. The results showed that this treatment effectively immobilized Pb and Cd in the sludge, lightly stabilized the metal Cu, and adversely, enhanced the leachability of Zn. After incineration at 900 °C, Pb and Cr in the bottom ash of pre-treated sludge were significantly stabilized due to the formation of their highly thermostable phosphates and pyromorphite-like minerals during the incineration process. However, an increase of Cu and Zn solubility was observed which might be attributable to the acidification of sludge due to the addition of PA or MCP.

In five-axis machining, tool orientation above a blade stream surface may lead to tool collision and a decrease in workpiece rigidity. Hence, collisionless tool orientation smoothing (TOS) becomes an important issue. On the basis of a constant scallop height tool path, the triangular facets in the faces, vertices format are constructed from cutter contact (CC) using the Voronoi incremental algorithm. The cutter location (CL) points candidate set is represented by an oblique elliptic cone whose vertex lies at CC using NURBS envelope. Whether the CL point is above its CC is judged by the dot product between the normal vector and the point on triangulation nearest to the CL point. The curvatures at CC are obtained by fitting a moving least square (MLS) quadratic patch to the local neighborhood of a vertex and calculating eigenvectors and eigenvalues of the Hessian matrix. Triangular surface elastic energy is employed as the weight in selection from the NURBS envelope. The collision is judged by NURBS surface intersection. TOS can then be expressed by selecting a CL point for each CC point and converted into a numerical control (NC) code automatically according to the postprocessor type of the machine center. The proposed method is verified by finishing of a cryogenic turboexpander impeller of air separation equipment.

This work presents a new analytical method to analyze the influence of reaction piles on the test pile response in a static load test. In our method, the interactive effect between soil and pile is simulated using independent springs and the shear displacement method is adopted to analyze the influence of reaction piles on test pile response. Moreover, the influence of the sheltering effect between reaction piles and test pile on the test pile response is taken into account. Two cases are analyzed to verify the rationality and efficiency of the present method. This method can be easily extended to a nonlinear response of an influenced test pile embedded in a multilayered soil, and the validity is also demonstrated using centrifuge model tests and a computer program presented in the literature. The present analyses indicate that the proposed method will lead to an underestimation of the test pile settlement in a static load test if the influence of the presence of reaction piles on the test pile response is neglected.

This study investigated characteristics of bifurcation and critical buckling load by shape imperfection of space truss, which were sensitive to initial conditions. The critical point and buckling load were computed by the analysis of the eigenvalues and determinants of the tangential stiffness matrix. The two-free-nodes example and star dome were selected for the case study in order to examine the nodal buckling and global buckling by the sensitivity to the eigen buckling mode and the analyses of the influence, and characteristics of the parameters as defined by the load ratio of the center node and surrounding node, as well as rise-span ratio were performed. The sensitivity to the imperfection of the initial shape of the two-free-nodes example, which occurs due to snapping at the critical point, resulted in bifurcation before the limit point due to the buckling mode, and the buckling load was reduced by the increase in the amount of imperfection. The two sensitive buckling patterns of the numerical model are established by investigating the displaced position of the free nodes, and the asymmetric eigenmode greatly influenced the behavior of the imperfection shape whether it was at limit point or bifurcation. Furthermore, the sensitive mode of the two-free-nodes example was similar to the in-extensional basis mechanism of a simplified model. The star dome, which was used to examine the influence among several nodes, indicated that the influence of nodal buckling was greater than that of global buckling as the rise-span ratio was higher. Besides, global buckling is occurred with reaching bifurcation point as the value of load ratio was higher, and the buckling load level was about 50%–70% of load level at limit point.

The original version of this article unfortunately contained a mistake. In p.597, the minus on the right side of Eq. (1) was incorrect. The correct version is given.

From the case study of Evening Bell Ringing at Nanping Hill, one of the West Lake Cultural Landscapes in Hangzhou, China, we investigated the soundscape of a scenic area with a profound cultural background. First, we conducted the soundscape physical index of the area in both winter and spring seasons to analyze its objective graphical expression. Second, we focused on people’s reactions to the soundscape in order to obtain a subjective evaluation of each component in the soundscape and integrated environment. Then, the relationship between the objective data and the subjective evaluation was analyzed. Finally, the impacts of the natural environment, history, and cultural factors on the evaluation of the Jingci Temple soundscape were studied. It was found that natural sounds, cultural sounds, and historic sounds were widely acclaimed in people’s subjective feelings, which indicated the close relationships among historical and cultural background, soundscape, and natural environment. Thus, the conclusion was made that soundscape should be consistent with the local natural environment and the historical and cultural background.