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Having read previous literature about vortex pump, we noticed that mechanisms of circulating flow and its relationship with energy transition remain unclear yet. However, this mechanism, which should be clarified, significantly influences the pump’s efficiency. To comply with the aim of investigating it, the 150WX-200-20 type pump is selected as study object in our present work.

Numerical simulation is conducted to formulate interactions between flow rate and geometric parameters of circulating flow with certain types of blade while experiments on inner flow are served as a witness to provide experimental confirmation of numerical results. Based on these, we coupled some parameters with the pump’s external performance to study their internal connections.

It is concluded that separatrix between circulating flow and other turbulent forms is not that clear under low flow rate. With flow increases, hydraulic losses coming of it will be dominant within the front chamber. Besides, we analogized circulating flow to vortices so as to make a quantitative analysis on its progressive evolution with changing flow, and vortices speaking for circulating flow can be divided into two groups. One is called main circulating flow vortex (hereinafter referred to as MCFV), which occurs all the time while subsidiary circulating flow vortices (hereinafter referred to as SCFV) appear in certain conditions. This context discusses the primary phase of our work with intent to follow up further with circulating flow characterized by vortices (hereinafter referred to as CFV). We confirmed that MCFV Vortex 1 (Vor1) directly influences the efficiency while SCFVs only play helping. As the flow goes to the given working condition, fluids in this pump tend to be steady with the size of CFVs getting larger and their shape being regular. Meanwhile, for MCFV Vor2 and Vor4, their geometric parameters are the key factors for efficiency. When CFVs become steady, they absorb other vortices nearby, as they have higher viscosity with the efficiency reaching its maximum.

The research results explore a new way to measure the circulating flow and help work out the causation of this flow pattern, which may be used to improve the vortex pump’s efficiency.

The special structure of the vortex pump contributes to its complex internal flow pattern. A type of horizontal 150WX-200-20 vortex pump is taken as a research subject to deeply study the progression and distribution of flow pattern in its channel. To explain the mechanism of flow in this pump, numerical analysis of the whole flow and experiment have been conducted.

The authors studied and analyzed the distribution and evolution of flow pattern under different flow, such as circulating-flow, through-flow and other forms. Finally, a model of flow pattern in the vortex pump has been built, which has more perfectly fit the reality.

They are through-flow affected by circulating-flow, main and subsidiary circulating-flow, vortices between vanes and other vortices (or liquid impingement) in volute. Entering the pump, part of the flow stays in vanes and turn into vortices while the other goes into the front chamber. The flow that runs into the front chamber will be divided into two parts. One part will be collected by viscosity into a vortex rope when it passing through the interface between the impeller and the vaneless chamber, which closely relates to the circulating-flow, and the rest directly goes out of the field through the diffuser. Besides, a fraction of circulating-flow joins the through-flow when it goes through the section V and leaves the pump.

The research results build a theoretical foundation for working out the flow mechanism of the vortex pump, improving its efficiency and optimizing its hydraulic design.

To analyze the work principle and capacity of energy conversion in each segment of profile lines, the energy transfer from impeller to transmission medium is separated into head coefficient and load coefficient to analyze the energy transfer process. The concepts of airfoil lift coefficient and drag coefficient are used; the third manifestation of the Euler equations is used as well.

The numerical simulation of energy conversion mechanism based on load criteria of vane airfoil has been established in screw centrifugal pump to explain its energy conversion mechanism in an impeller. Upon this basis, the velocity and pressure along the entire blade are investigated through the numerical simulation of internal solid–liquid flow in the pump. The energy conversion process under load criteria in the blade airfoil has also been obtained.

The research suggests that the mathematical model of energy conversion mechanism based on the load criteria of the vane airfoil is reliable in the screw centrifugal pump. The screw centrifugal blade has twice or even several times the wrap angle than the ordinary centrifugal blade. It is a large wrap angle that forms the unique flow channel which lays the foundation for solid particles to pass smoothly and for soft energy conversion. At the same time, load distribution along the profile line on the long-screw centrifugal blade is an important factor affecting the energy conversion efficiency of the impeller.

The quantitative analysis method of energy in the screw centrifugal pump can help the pump designer improve certain features of the pump and shorten the research cycle.

The purpose of paper is to investigate the dissatisfaction and what specifically prompts multi-owned housing owners to change their body corporate management provider. Globally there has been a substantial growth reported in the number of residents living in multi-owned housing in recent years. There is increasing evidence that residents in these developments are experiencing dissatisfaction and frustration especially with the service received from their body corporate management company.

The paper includes a review of both the body corporate literature and customer switching literature which serves to inform the research. The investigation takes the form of a qualitative study comprising eight in-depth one-to-one interviews with residential body corporate owners who have recently switched to an alternative body corporate management provider.

The dissatisfaction experienced by body corporate owners leading them to change management companies bears a close similarity to the retail banking industry. The interviews record highly emotive responses from interviewees and the desire for an improved quality of service and better value for money from their service provider. These findings allow a deeper understanding of the outcome of studies that have been carried out previously in England and New Zealand.

The findings will assist directors of body corporate companies, property management and real-estate companies to understand the needs and wants of their clients and may also benefit property developers in their selection of a body corporate management company and legislators in providing a suitable legal framework.

This paper provides in-depth insights into switching behaviour within the context of body corporate management companies which has not before been published within academic journals.

The purpose of this paper is to discuss sentiment search, which not only retrieves data related to submitted keywords but also identifies sentiment opinion implied in the retrieved data and the subject targeted by this opinion.

The authors propose a retrieval framework known as Cross-Domain Sentiment Search (CSS), which combines the usage of domain ontologies with specific linguistic rules to handle sentiment terms in textual data. The CSS framework also supports incrementally enriching domain ontologies when applied in new domains.

The authors found that domain ontologies are extremely helpful when CSS is applied in specific domains. In the meantime, the embedded linguistic rules make CSS achieve better performance as compared to data mining techniques.

The approach has been initially applied in a real social monitoring system of a professional IT company. Thus, it is proved to be able to handle real data acquired from social media channels such as electronic newspapers or social networks.

The authors have placed aspect-based sentiment analysis in the context of semantic search and introduced the CSS framework for the whole sentiment search process. The formal definitions of Sentiment Ontology and aspect-based sentiment analysis are also presented. This distinguishes the work from other related works.

The purpose of this paper is to construct a novel delay grey incidence analysis model to analyze drivers and obstacles of university R&D performance.

With respect to the fact that university R&D activities typically experience two stages of knowledge creation and technology transfer, and different drivers and obstacles come into play to affect the conversion of R&D investment to outcomes at each stage, based on the thought of grey incidence analysis and the specific characteristics of science and technology (sci-tech) development, a novel delay grey incidence analysis model is proposed in this paper, and then according to the yearbook statistical data, Chinese university R&D activities are investigated and the drivers and obstacles of university R&D performance are analyzed.

The results show that the R&D full-time staff and R&D funds of basic research are the key drivers of influencing factors, and the sci-tech innovation talents in universities’ R&D institutions and experiment development funds are the restraining factors to improve R&D performance in the stage of knowledge creation; the expenses of R&D achievement application and technology service and the full-time staff of achievement application and technology service are the key drivers and obstacles of influencing the aggregate amount of patent sale respectively.

This research helps policy makers to reflect on their university R&D policies and understand how to enhance the technology transfer rate in China.

The paper succeeds in identifying key drivers and obstacles of affecting university R&D performance in China by examining the input and output incidence at both the knowledge creation and technology transfer stages.

With the proliferation of virtual reality (VR) applications in electronic commerce, investigations on the effects of VR on consumer responses are important. The purpose of this paper is to examine the effects of online presentation modes (i.e. situational VR, pure VR and picture) on consumer responses for three product types (i.e. geometric, material and mechanical).

This study conducted a 3×3 between-subjects experiment to validate the research model and hypotheses.

The results revealed that both the situational VR mode and the pure VR mode had a greater impact on product knowledge and purchase intention than the picture mode. The situational VR mode yielded a higher level of product knowledge and purchase intention than the pure VR mode although it was not statistically significant. Furthermore, the pattern of VR modes superiority was found to be consistent across geometric, material and mechanical product types.

This research study contributes to the VR literature by investigating a new type of VR: situational VR, and offering a more comprehensive picture of consumer responses to online product presentations. The authors then drew the implications from the findings to suggest guidelines for practitioners to efficiently allocate resources and maximize the effectiveness of online presentation modes.

Information carriers (including mass media and We-Media) play important roles in information diffusion on social networks. The purpose of this paper is to investigate changes in the dissemination of information combing with data analysis.

This work analyzed nearly 200 years of coverage of different information carriers during different periods of human society, from the period of only mouth-to-mouth communication to the period of modern society. Information diffusion models are built to illustrate how the information dynamic changes with time and combined box office data of several movies to predict the process of information diffusion. In addition, a metric is defined to identify which information would become news in the future.

Results show that with the development of information carriers, information spreads faster and wider nowadays. The correctness of the metric proposed has been validated.

The structure of social networks influences the dissemination of information. There are an enormous number of factors that influence the formation of hotspots.

The results and conclusion of this work will benefit by predicting the evolution of information carriers. The metric proposed will aid in searching hot news in the future.

This work may shed some light on a better understanding of information diffusion, spreading not only on social networks but also on the carriers used for the information spreading.

Variable fractional delay filtering is an important technology in signal processing; the research shows that all-pass variable fractional delay (VFD) filters achieve higher design accuracy than FIR VFD filters; therefore, the design, analysis and implementation of all-pass VFD filters are of great importance.

In this paper, a two-stage approach for the design of general 1-D stable VFD all-pass filters is proposed. The method takes the desired group delay range [N−1, N], where N is the filter order.

The design algorithm is decomposed into two design stages: first, a set of fixed delay all-pass filters are designed by minimizing a set of objective functions defined in terms of approximating error criterion and filter stability constraint. Then, the design result is determined by fitting each of the fixed delay all-pass filter coefficients as 1-D polynomials. A design example together with its comparisons with those of the recent literature studies is given to justify the effectiveness of the proposed design method.

An illustrating design example shows that the method proposed can achieve better filter performances than the existing ones.

This exploratory qualitative study examines both the impact of mental health conditions on self-perceived job performance and how individuals with mental health conditions cope with their conditions at work.

A total of 257 responses to a qualitative questionnaire and 17 in-depth interviews with individuals with mental health conditions are analyzed.

The findings show that mental health conditions can negatively impact self-perceived job performance in the form of lower quality of one's work, slower pace, and more mistakes. In addition, the findings reveal coping strategies that positively and negatively affect one’s performance at work. Strategies that negatively influence one’s performance include substance abuse and self-harm, suppressing and hiding one's symptoms, and forcing oneself to continue to work when feeling unwell. Coping strategies that tend to positively affect their performance include accepting one's condition and taking time off, medication and counseling, mindfulness activities, transparent communication, humor, and a compensation strategy.

A growing number of individuals struggle with mental health conditions at work, impacting both organizations and employees. However, little is known about the influence of mental health conditions on one's performance at work, how individuals cope with their mental health conditions at work, and what effect those coping strategies have on organization-relevant outcomes.