Search results

Joule heating effect is a pervasive phenomenon in electro-osmotic flow because of the applied electric field and fluid electrical resistivity across the microchannels. Its effect in electro-osmotic flow field is an important mechanism to control the flow inside the microchannels and it includes numerous applications.

This research article details the numerical investigation on alterations in the profile of stream wise velocity of simple Couette-electroosmotic flow and pressure driven electro-osmotic Couette flow by the dynamic viscosity variations happened due to the Joule heating effect throughout the dielectric fluid usually observed in various microfluidic devices.

The advantages of the Joule heating effect are not only to control the velocity in microchannels but also to act as an active method to enhance the mixing efficiency. The results of numerical investigations reveal that the thermal field due to Joule heating effect causes considerable variation of dynamic viscosity across the microchannel to initiate a shear flow when EDL (Electrical Double Layer) thickness is increased and is being varied across the channel.

This research work suggest how joule heating can be used as en effective mechanism for flow control in microfluidic devices.

The purpose of this paper is to shed light on the changing pattern and characteristics of international financial flows in the emerging entrepreneurial ecosystems of Sub-Saharan Africa (SSA), provide a novel taxonomy to classify and analyze them, and discuss how such investments contribute to competence building and sustainable development.

In an exploratory study, the authors analyze the characteristics of international venture capital investors and the start-ups receiving funding in Kenya and map their interaction. The authors proceed by developing a novel taxonomy, classifying investors according to their main rationales (for-profit-for-impact), and start-ups according to the locus of needs and markets addressed by the start-up (local-global) and the locus of the start-ups capacity and knowledge (local-global).

The authors observe a new type of mainly western investors who support innovative ideas in SSA by identifying and investing in domestically developed technical innovations with the potential to address global market needs. The authors find such innovations to be mainly developed at the intersect of global and local knowledge.

The authors shed light on the – up to now – under-researched emerging phenomenon of international high-tech investments in SSA, and develop a novel taxonomy of technology investments in low-income countries, guiding further research on the conditions, impact, practical, and policy implications of this new form of finance flows.

World trade has been increasing rapidly and much faster than world output. This study analyzes the trade structures of major dynamic East Asian countries as well as regional subgroups such as ASEAN members and Northeast Asian countries. Emphasis will be on the complementarities that would enhance integration among them through international trade. In addition, potential trade levels for each combination of East Asian countries are estimated by applying the gravity model of trade to the trade flows of21 APEC members, as a reference group. It is estimated to have significant potentiality by regional subgroup, ASEAN or Northeast Asia, and not between the two regional subgroups. However, the potential integration between East Asian countries in different regional subgroups is more significant by considering complementarities in trade compared with the results from the basic gravity model. To enhance economic cooperation between East Asian countries, expanding relationships such as inter-industry trade in natural resources trade and industrial goods between the regional subgroups needs to occur. They should also utilize complementary relationships from intra-industry trade in industrial goods such as electric and electronic equipment, related parts and accessories. And they should focus on the implementation of trade facilitation measures based on global standards.

This study proposes spatial origin-destination threshold Tobit to address spatial interdependence among bilateral trade flows while accounting for zero trade volumes.

This model is designed to capture multiple forms of spatial autocorrelation embedded in “directional” trade flows. The authors apply this improved model to export flows among 32 Asian countries in 1990.

The empirical results indicate the presence of all three types of spatial dependence: exporter-based, importer-based and exporter-to-importer-based. After further considering multifaceted spatial correlation in bilateral trade flows, the authors find that the effect of conventional trade variables changes in a noticeable way.

This finding implies that the standard gravity model may produce biased estimates if it does not take spatial dependence into account.

This paper attempts to offer an improved model of the standard gravity model by taking spatial dependence into account.

The purpose of this paper is to analyze whether companies that contracted loans from the Brazilian National Bank for Economic and Social Development (BNDES) between 2002 and 2014 were able to invest more than companies that did not. The literature on financial constraints, particularly that based on the investment-cash flow sensitivity model, is among the most studied and controversial in the area of finance, and the discussion on the role of development banks is equally controversial.

The main econometric model of this study was based on the investment-cash flow sensitivity model, with the incorporation of a binary variable that captures the role of the BNDES. This model is applied to a sample of companies listed on the B3 from 2002 to 2014.

This study shows that loans from the BNDES amplify the effects of cash flow on investments, generating a kind of credit multiplier. An important role of development banks is to reduce the financial constraints typical of developing countries.

The use of the cash flow sensitivity model in companies that contracted loans from the BNDES is a relevant instrument to test the effect of the BNDES on companies with financial constraints.

The contracting of BNDES loans by companies can affect both capital structure and cash generation, particularly in companies or years in which there was financial constraint.

Due to the nature of the BNDES as a development bank, there are ramifications in terms of the generation of employment and income inherent to the mission of this type of institution. Knowing the multiplier effect on the cash flow potential of companies has a direct impact on their preservation, enabling them to maintain and expand the supply of jobs.

This study is the first to integrate two important areas of study. From the theoretical perspective, this study provides evidence on the relationship between the BNDES and company financial constraints that open new avenues of research. From the managerial point of view, the evidence of the multiplier effect is highly important for the management of the capital structure and cash flow of companies.

An integrative model that predicts users' stickiness to WeChat is built. In the proposed model, perceived value plays a dual mediating role in the causal pathway from users' immersive experiences of presence and flow to their engagement and stickiness. Furthermore, presence is treated as a bi-dimensional construct made up of spatial feelings and the sense of being in company, and users' engagement is conceived as cognitive, affective and behavioural contributions to WeChat's marketing functions.

The authors develop a measurement instrument and analyse data from a survey of 917 WeChat users. They use a hybrid partial least squares-structural equation modelling (PLS-SEM) and neural network approach to confirm the reliability and validity of the measurement items and all the relationships between the constructs.

The paper provides robust evidence about the mediating influences of both utilitarian and hedonic value on users' engagement with the immersive experiences of presence and flow. An additional finding highlights the role of social norms in engagement and stickiness.

Rather than studying the effects of the immersive experiences of presence and flow from either a hedonic or a utilitarian perspective, the authors consider how immersive experiences shape both utilitarian and hedonic value, as well as their joint impact (along with that of social norms) on users' engagement and stickiness.

Using positive psychology theories, the authors build a model to test whether episodic fluctuations in strengths use coincide with changes in flow experiences and further predict risk-taking behavior and attentional performance.

A field study covering five working days was conducted among 164 Chinese employees; twice a day, they were asked to complete questionnaires regarding their strengths use and flow experiences during the previous hour (N = 938 observations). Immediately afterward, their risk-taking behaviors and attentional performance were tested using computerized tasks.

Multilevel analyses showed that when employees used their strengths more often in the previous hour, they also reported an increase in flow. Episodic fluctuations in flow were positively associated with risk taking and negatively related to attentional performance.

Employees should be encouraged to use their strengths more at work, as this might increase their flow experiences. At the same time, they should pay attention to the downsides of flow (i.e. less attention after flow) at an episodic level.

The authors add to previous studies by using a more objective approach, namely employing computerized tasks on risk-taking behavior and attention to capture the behavioral outcomes of work-related flow.

In this study, the authors sought to investigate how the implicit social ties of both project owners and potential backers are associated with crowdfunding project success.

Drawing on social ties theory and factors that affect crowdfunding success, in this research, the authors developed a model to study how project owners' and potential backers' implicit social ties are associated with crowdfunding projects' degrees of success. The proposed model was empirically tested with crowdfunding data collected from Kickstarter and social media data collected from Twitter. The authors performed the test using an ordinary least squares (OLS) regression model with fixed effects.

The authors found that project owners' implicit social ties (specifically, their social media activities, degree centrality and betweenness centrality) are significantly and positively associated with crowdfunding projects' degrees of success. Meanwhile, potential project backers' implicit social ties (their social media activities and degree centrality) are negatively associated with crowdfunding projects' degrees of success. The authors also found that project size moderates the effects of project owners' social media activities on projects' degrees of success.

This work contributes to the literature on crowdfunding by investigating how the implicit social ties of both potential backers and project owners on social media are associated with crowdfunding project success. This study extends the previous research on social ties' roles in explaining crowdfunding project success by including implicit social ties, while the literature explored only explicit social ties.

The most sustainable forms of urban mobility are walking and cycling. These modes of transportation are the most environmental friendly, the most economically viable and the most socially inclusive and engaging modes of urban transportation. To measure and compare the effectiveness of alternative pedestrianization or cycling infrastructure plans, the authors need to measure the potential flows of pedestrians and cyclists. The paper aims to discuss this issue.

The authors have developed a computational methodology to predict walking and cycling flows and local centrality of streets, given a road centerline network and occupancy or population density data attributed to building plots.

The authors show the functionality of this model in a hypothetical grid network and a simulated setting in a real town. In addition, the authors show how this model can be validated using crowd-sensed data on human mobility trails. This methodology can be used in assessing sustainable urban mobility plans.

The main contribution of this paper is the generalization and adaptation of two network centrality models and a trip-distribution model for studying walking and cycling mobility.

The aviation industry has seen consistent growth over the past few decades. To maintain its sustainability and competitiveness, it is important to have a comprehensive understanding of the environmental impacts across the entire life cycle of the industry, including materials, processes and resources; manufacturing and production; lifetime services; reuse; end-of-life; and recycling. One important component of aircraft engines, integral rotors known as Blisks, are made of high-value metallic alloys that require complex and resource-intensive manufacturing processes. The purpose of this paper is to assess the ecological and economical impacts generated through Blisk production and thereby identify significant ‘hot-spots’.

This paper focuses on the methodology and approach for conducting a full-scale Blisk life cycle assessment (LCA) based on ISO 14040/44. Unlike previous papers in the European Aerospace Science Network series, which focused on the first two stages of LCA, this publication delves into the “life cycle impact assessment” and “interpretation” stages, providing an overview of the life cycle inventory modeling, impact category selection and presenting preliminary LCA results for the Blisk manufacturing process chain.

The result shows that the milled titanium Blisk has a lower CO₂ footprint than the milled nickel Blisk, which is less than half of the global warming potential (GWP) of the milled nickel Blisk. A main contributor to GWP arises from raw material production. However, no recycling scenarios were included in the analysis, which will be the topic of further investigations.

The originality of this work lies in the detailed ecological assessment of the manufacturing for complex engine components and the derivation of hot spots as well as potential improvements in terms of eco-footprint reduction throughout the products cradle-to-gate cycle. The LCA results serve as a basis for future approaches of process chain optimisation, use of “greener” materials and individual process improvements.