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The purpose of this paper is to investigate thermoregulation properties of different composite phase change materials (PCMs), which could be used in the high temperature environmental conditions to protect human body against the extra heat flow.

Three kinds of composite PCM samples were prepared using the selected pure PCMs, including n-hexadecane, n-octadecane and n-eicosane. The DSC experiment was performed to get the samples’ phase change temperature range and enthalpy. The simulated high temperature experiments were performed using human arms in three different high temperature conditions (40°C, 45°C, 50°C), and the skin temperature variation curves varying with time were obtained. Then a comprehensive index TGP was introduced from the curves and calculated to evaluate the thermoregulation properties of different composite PCM samples comprehensively.

Results show that the composite PCM samples could provide much help to the high temperature human body. It could decrease the skin temperature quickly in a short time and it will not cause the over-cooling phenomenon. Comparing with other two composite PCM samples, the thermoregulation properties of the n-hexadecane and n-eicosane composite PCM is the best.

Using the n-hexadecane and n-eicosane composite PCM may provide people with better protection against the high temperature conditions, which is significative for the manufacture of functional thermoregulating textiles, garments or equipments.

Purpose – We investigate the impact of CEO turnover on performance and accounting-based outcomes following major business restructurings.

Design/Methodology/Approach – We analyze a sample of 217 major operational restructurings during the period 1999–2007 using regressions and other statistical tests.

Findings – We document significant improvements in postrestructuring operating and investment efficiencies with little differentiation between restructurings that involve a change in CEO and those that involve continuing CEOs. However, we find evidence of lower accounting quality for the continuing CEO firms. First, restructuring charges of CEO turnover firms are associated with lower current period unexpected core earnings and higher future period unexpected core earnings (lower levels of classification shifting). Second, CEO turnover firms have a significantly lower percentage of (i) restructuring charge reversals and (ii) prereversal shortfalls (in meeting analyst forecast estimates) followed by reversals (suggesting lower levels of subsequent earnings management). Therefore, turnover CEOs are less likely to manipulate restructuring charges to mask true economic performance than continuing CEOs. Overall, our evidence suggests continuing CEOs undertake less substantial restructurings, while opportunistically reporting similar charges and performance improvements, consistent with attempts to pool with new CEO hires to keep their jobs.

Originality/Value – Overall, our results highlight the key economic role played by top corporate managers in major business restructurings, suggesting that CEO turnover leads to both real changes in managerial actions and altered reporting incentives.

This paper aims to define an extended QoS model to accurately describe the quality of web service in the open distributed environment and propose a fuzzy evaluation approach for services selection based on the extended QoS model.

The extended QoS model classifies the quality criteria of web service as five composite quality criteria, and each composite quality criterion is composed by one or more sub‐quality criteria. Considering the multiple forms of representation for the quality criteria and different types of quality value could not be compared directly, a scaling fuzzy measure for quality criteria is introduced. Based on the scaling fuzzy measure of the quality criteria, a fuzzy synthetic evaluation system for services selection is proposed.

The quality of web service has multiple facets and multiple forms of representation. The fuzzy synthetic evaluation system can deal well with the fuzzy and implicit concepts about quality evaluations and provides higher expressive force and adaptability.

The quality of service in this paper is static preset.

The extended QoS model and the synthetic fuzzy evaluation system cover the shortage of the related researches and lay the foundations for QoS‐oriented service description and services selection.

The wire and arc additive manufacturing (WAAM) is a promising technology, but the parts are mostly manufactured on the plane and along the vertical direction. The purpose of this paper is to propose a cylindrical slicing and manufacturing method.

For revolved parts, e.g. blades of a propeller, instead of planes, a series of cylindrical surfaces intersect with the STL model of the part. The generated slicing layers lie on the cylindrical surface, and then these spatial contours are unfolded onto the plane by the use of the cylindrical coordinate system. A deposition system based on an NC machine is established to examine deposition paths. The temperature and stress of part of two deposition orders are analyzed using the finite element method.

The scan parallel path and contour offset path are not suitable to fabricate blades directly. The hybrid of two types of paths and the hybrid of skeleton and contour offset paths are capable of forming blades without gaps. Deposition symmetrically can decrease the deformation of the propeller.

The slicing algorithm is simply implemented and practicable for any parts. The recognition of gaps and supplementary skeleton path can guarantee the full deposition of contour offset paths.

This study aims to explore the relationship between network position, various types of inter-organizational conflicts and project performance in the context of megaprojects.

Centrality and structural holes were used to represent network position. A theoretical model was developed, and a structured questionnaire survey was conducted with construction professionals involved in megaprojects. A total of 291 valid responses were obtained, which were analyzed via structural equation modeling.

The results showed that centrality negatively impacts project performance, while structural holes do not significantly impact project performance. Centrality negatively affects task conflicts, but positively affects process conflicts and relationship conflicts. Structural holes positively impact task conflicts, but negatively impact both process conflicts and relationship conflicts. Task conflict and relationship conflict exert constructive and destructive effects on project performance, respectively, while process conflict does not significantly impact project performance. Task conflict and relationship conflict play mediating roles. Task conflict weakens while relationship conflict strengthens the relationship between centrality and project performance. Task conflict strengthens while relationship conflict weakens the relationship between structure hole and project performance.

This study provides a reference for the implementation of network governance, inter-organizational conflict management and project performance management in megaprojects. However, the impact of dynamic changes of inter-organizational conflicts and network position on project performance has not been discussed in the context of megaprojects. Future research may explore the impact of dynamic changes of conflicts and network position on project implementation.

This study increases the current understanding of the impact of network position on project performance. Moreover, a new direction for network governance in the context of megaprojects is provided. This study also verified both the constructive and destructive effects of conflicts and the mediating role they play, thus supplementing the literature on inter-organizational conflict management in the construction field.

With the popularity of high-rise buildings, wall inspection and cleaning are becoming more difficult and associated with danger. The best solution is to replace manual work with wall-climbing robots. Therefore, this paper proposes a design method for a rolling-adsorption wall-climbing robot (RWCR) based on vacuum negative pressure adsorption of the crawler. It can improve the operation efficiency while solving the safety problems.

The pulleys and tracks are used to form a dynamic sealing chamber to improve the dynamic adsorption effect and motion flexibility of the RWCR. The mapping relationship between the critical minimum adsorption force required for RWCR downward slip, longitudinal tipping and lateral overturning conditions for tipping and the wall inclination angle is calculated using the ultimate force method. The pressure and gas flow rate distribution of the negative pressure chamber under different slit heights of the negative pressure mechanism is analysed by the fluid dynamics software to derive the minimum negative pressure value that the fan needs to provide.

Simulation and test results show that the load capacity of the RWCR can reach up to 6.2 kg on the smooth glass wall, and the maximum load in the case of lateral movement is 4.2 kg, which verifies the rationality and effectiveness of the design.

This paper presents a new design method of a RWCR for different rough wall surfaces and analyses the ultimate force state and hydrodynamic characteristics.

This paper aims to explore the effects of mineral diesel fuel carbon soot (MCS) and biodiesel carbon soot (BCS) on the lubrication of polyalphaolefin (PAO) and diesel fuels.

Two styles of carbon soot were prepared from the natural combustion of mineral diesel fuel oil (MDO) and biodiesel oil (BDO). Tribological tests were conducted on a high-frequency reciprocating rig. Friction surfaces were characterized using three-dimensional laser scanning confocal microscopy and Raman spectroscopy.

The addition of MCS and BCS to PAO could reduce friction in most cases. MCS had a negligible effect on the wear for contents not exceeding 1.0 per cent. By contrast, BCS exhibited a considerable negative influence on the wear resistance even at low contents. For diesel fuels, MCS reduced both friction and wear, whereas BCS substantially deteriorated the lubrication of BDO. MCS formed a Fe₃O₄/C composite lubricating film on the friction surface. BCS also entered the contact region, but it did not form an effective Fe₃O₄/C composite lubricating film.

This work compared MDO and BDO from a different perspective, i.e. the effects of their combustion carbon soot on the lubrication of lubricating oil and fuel oil. The significant negative effect of BCS on the lubrication of lubricating oil and BDO is a problem that could occur in the industrial application of BDO.

This study aims to fabricate and manipulate ensemble spin of negative nitrogen-vacancy (NV⁻) centres optimally for future solid atomic magnetometers/gyroscope. Parameters for sample preparation most related to magnetometers/gyroscope are, in particular, the concentration and homogeneity of the NV⁻ centres, the parameters’ microwave antenna of resonance frequency and the strength of the microwave on NV⁻ centres. Besides, the abundance of other impurities such as neutral NV centres (NV⁰) and substitutional nitrogen in the lattice also plays a critical role in magnetic sensing.

The authors succeeded in fabricating the assembly of NV centres in diamond and they determined its concentration of (2-3) × 10¹⁶ cm⁻³ with irradiation followed by annealing under a high temperature condition. They explored a novel magnetic resonance approach to detect the weak magnetic fields that takes advantage of the solid-state electron ensemble spin of NV⁻ centres in diamond. In particular, the authors set up a magnetic sensor on the basis of the assembly of NV centres. They succeeded in fabricating the assembly of NV centres in diamond and determined its concentration. They also clarified the magnetic field intensity measured at different positions along the antenna with different lengths, and they found the optimal position where the signal of the magnetic field reaches the maximum.

The authors mainly reported preparation, initialization, manipulation and measurement of the ensemble spin of the NV centres in diamond using optical excitation and microwave radiation methods with variation of the external magnetic field. They determined the optimal parameters of irradiation and annealing to generate the ensemble NV centres, and a concentration of NV⁻ centres as high as 10¹⁶ cm⁻³ in diamond was obtained. In addition, they found that sensitivity of the magnetometer using this method can reach as low as 5.22 µT/Hz currently.

This research can shed light on the development of an atomic magnetometer and a gyroscope on the basis of the ensemble spin of NV centres in diamond.

High concentration spin of NV⁻ in diamond is one of the advantages compared with that of the atomic vapor cells, because it can obtain a higher concentration. When increasing the spin concentration, the spin signal is easy to detect, and macro-atomic spin magnetometer become possible. This research is the first step for solid atomic magnetometers with high spin density and high sensitivity potentially with further optimization. It has a wide range of applications from fundamental physics tests, sensor applications and navigation to detection of NMR signals.

As has been pointed out, in this research, the authors mainly worked on fabricating NV⁻ centres with high concentration (10¹⁵-10¹⁶ cm⁻³) in diamond by using optimal irradiation and annealing processes, and they quantitatively defined the NV⁻ concentration, which is important for the design of higher concentration processes in the magnetometer and gyroscope. Until now, few groups can directly define the NV⁻ concentration. Besides, the authors optimized the microwave antenna parameters experimentally and explored the dependence between the splitting of the magnetic resonance and the magnetic fields, which dictated the minimum detectable magnetic field.

The purpose of this paper is to evaluate the cogging torque in a surface-mounted permanent magnet (SPM) machine with both uniformly and non-uniformly segmented stator cores and to find out the optimal solution of stator core segmenting.

The cogging torque with segmented stators is synthesized from a single slot model, and analytical prediction is given to analyze the cogging torque with both uniformly and non-uniformly segmented stators. Finite element method (FEM) is used to figure out the electromagnetic field and validate the analytical prediction. Moreover, models with various shapes and positions of connecting tongues between the stator core segments are explored to achieve the optimal design.

The cogging torque is found to be greatly related to the number of segments and the electrical angle between adjacent additional air gaps caused by the tolerance of stator segments. Different shapes of the connecting tongues are tested and proved to be of great importance to the flux density, both radial and tangential, and therefore affect the cogging torque. Finally, position of the connecting tongues is perceived to have little influence on the performance of machine.

By utilizing analytical prediction and FEM calculation, the optimal solution is discussed to minimize the cogging torque in the SPM machine from the perspective of the stator core segmentation.

This paper establishes formula of cogging torque with segmented stators and predicts the variation of cogging torque with analytical method. Besides, different combinations of segments are compared and measures to reduce the cogging torque produced by the segmentation are proposed.