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The rapid development of three-dimensional (3D) printing makes it familiar in daily life, especially the fused deposition modeling 3D printers. The process planning of traditional flat layer printing includes slicing and path planning to obtain the boundaries and the filling paths for each layer along the vertical direction. There is a clear division line through the whole fabricated part, inherited in the flat-layer-based printed parts. This problem is brought about by the seam of the boundary in each layer. Hence, the purpose of this paper is to propose a novel helical filling path generation with the ideal surface-plane intersection for a rotary 3D printer.

The detailed algorithm and implementation steps are given with several worked examples to enable readers to understand it better. The adjacent points obtained from the planar slicing are combined to generate each layer's helical points. The contours of all layers are traversed to obtain the helical surface layer and helical path. Meanwhile, the novel rotary four-degree of freedom 3D printer is briefly introduced.

As a proof of concept, this paper presents several examples based on the rotary 3D printer designed in the authors’ previous research and the algorithms illustrated in this paper. The preliminary experiments successfully verify the feasibility and versatility of the proposed slicing method based on a rotary 3D printer.

This paper provides a novel and feasible slicing method for multi-axis rotary 3D printers, making manufacturing thin-wall and complex parts possible. To further broaden the proposed slicing method’s application in further research, adaptive tool path generation for flat and curved layer printing could be applied with a combination of flat and curved layers in the same layer, different layers or even different parts of structures.

With the development of 3D printing or additive manufacturing (AM), curved layer fused deposition modeling (CLFDM) has been researched to cope with the flat layer AM inherited problems, such as stair-step error, anisotropy and the time-cost and material-cost problems from the supporting structures. As one type of CLFDM, cylindrical slicing has obtained some research attention. However, it can only deal with rotationally symmetrical parts with a circular slicing layer, limiting its application. This paper aims to propose a ray-based slicing method to increase the inter-layer strength of flat layer-based AM parts to deal with more general revolving parts.

Specifically, the detailed algorithm and implementation steps are given with several examples to enable readers to understand it better. The combination of ray-based slicing and helical path planning has been proposed to consider the nonuniform path spacing between the adjacent paths in the same curved layer. A brief introduction of the printing system is given, mainly including a 3D printer and the graphical user interface.

The preliminary experiments are successfully conducted to verify the feasibility and versatility of the proposed and improved slicing method for the revolving thin-wall parts based on a rotary 3D printer.

This research is early-stage work, and the authors are intended to explore the process and show the initial feasibility of ray-based slicing for revolving thin-wall parts using a rotary 3D printer. In general, this research provides a novel and feasible slicing method for multiaxis rotary 3D printers, making manufacturing revolving thin-wall and complex parts possible.

The purpose of this paper is to separate and purify flavonoids from glycyrrhiza by macroporous adsorption resin (MAR) mixed-bed technology.

The adsorption performance of MAR and MAR mixed bed for flavonoids was studied using ultraviolet-visible spectrophotometry.

The research shows that the MAR mixed bed of LZ-50+LZ-59 with a mass ratio of LZ-50:LZ-59(m:m) = 1:1 was the optimized combination with the optimal conditions of adsorption (pH = 6, T = 45°C) and desorption (liquid ratio R = 70%, T = 50°C, pH = 8) obtained, relatively.

This paper provides a novel way to separate flavonoids from glycyrrhiza. Under the optimal conditions, the adsorption rate (F) of MAR mixed-bed LZ-50+LZ-59 to the flavonoids was 62.5 per cent/g, the desorption rate (D) was 89.23 per cent and the purity was achieved at 80 per cent.

The purpose of this paper is to prepare a higher chloromethylation degree (CD) modified macroporous adsorption resin (MAR, LX1180-Cl) and further study their adsorption performance.

CD and crosslinking degree were evaluated using stationary potential step and rotating-disk method, the adsorption performance of LX1180-Cl and LX1180 for flavonoids were studied using the UV-VIS spectrophotometry.

This research realized high CD (9.6 mass %) on high crosslinking MAR, LX1180. In tandem, the adsorption performance of them to flavonoids finds that the matching degree of polarity (presented with CD) and size were the critical factor to adsorption. It was also found that the reaction time had reduced to 24 h with the addition of iron particles into the zinc chloride (ZnCl₂) catalyst.

The study on reaction mechanism and the function principle of hybrid catalyst were speculated, but not the rigid experimental result.

This contribution can provide a rule for the separation and purification of natural products with the aim to improve food additive removal or isolation and purification of flavonoids used for healthcare applications.

This contribution provided a novel way to obtain high degree of CD with high crosslinking MAR, CD of commercially available MAR was improved by 2.5 times to 9.6 percent under crosslinking degree at 58.2 percent, compared with reported CD value (ca. 4.2 percent under crosslinking degree at 20.0 percent), which will be useful in the following further systematically research about the adsorption and separation selectivity of MAR. Besides, the primitive chosen principle of MAR according to the substrate was also presented. Moreover, the chloromethylation mechanism, although speculative, was briefly presented, which will stimulate the related study.

The purpose of this paper is to study the behavior of smoke flow in building fires and optimize the design of smoke control systems.

A total of 435 3-D fire simulations were conducted through NIST fire dynamics simulator to analyze thermal behavior of combined buoyancy-induced and pressure-driven smoke flow in complex vertical shafts, under consideration of influence of heat release rate (HRR) and locations of heat sources. This influence was evaluated through neutral pressure plane (NPP), which is a critical plane depicting the flow velocity distributions. Hot smoke flows out of shafts beyond the NPP and cold air flows into shafts below the NPP.

Numerical simulation results show that HRR of heat source has little influence on NPP, while location of heat source can make a significant difference to NPP, particularly in cases of multi-heat source. Identifying the location of NPP helps to develop a more effective way to control the smoke with less energy consumption. Through putting an emphasis on smoke exhausting beyond the NPP and air supplying below the NPP, the smoke control systems can make the best use of energy.

Because of the chosen research approach, the research results may need to be tested by further experiments.

The paper includes implications for the optimization of smoke control systems design in buildings.

This paper fulfills an identified need to research the behavior of hot smoke in building fires and optimize the design of smoke control systems.

The contribution of the public–private partnership (PPP) model towards the achievement of the United Nation (UN)'s Sustainable Development Goals (SDGs) has been widely acknowledged. However, limited studies have shed light on the connection between PPPs and the achievement of these coveted goals in Ghana. In this study, the authors aimed at analysing and synthesising the existing literature on the use of PPP to achieve sustainability in infrastructure projects in the country.

A three-step approach was used to retrieve and review 60 selected articles aided by content analysis.

The analysis showed that all existing relevant publications on the application of the PPP model to attain UN’s SDGs in the country are organised around dominant themes, such as poverty alleviation, urban development, waste management and risk management. However, the review revealed little studies exist on pertinent issues relating to PPPs and sustainable development goals, such as climate action, critical resilience, sustainable finance and clean energy.

Although the study is limited to 60 articles in Ghana, the results reveal pertinent gaps for further research studies to achieve sustainable infrastructural development in Ghana and other countries.

Holistically, the outcome of this study will serve as a guide to project managers to understand essential issues on attaining sustainability on public projects.

This article contributes to the literature and practice on the significance of PPP in mainstreaming UN's SDGs in public infrastructure projects.