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In this paper, a high-frequency radar test system was used to collect the data of clean ballast bed and fouled ballast bed of ballasted tracks, respectively, for a quantitative evaluation of the condition of railway ballast bed.

Based on original radar signals, the time–frequency characteristics of radar signals were analyzed, five ballast bed condition characteristic indexes were proposed, including the frequency domain integral area, scanning area, number of intersections with the time axis, number of time-domain inflection points and amplitude envelope obtained by Hilbert transform, and the effectiveness and sensitivity of the indexes were analyzed.

The thickness of ballast bed tested at the sleep bottom by high-frequency radar is up to 55 cm, which meets the requirements of ballast bed detection. Compared with clean ballast bed, the values of the five indexes of fouled ballast bed are larger, and the five indexes could effectively show the condition of the ballast bed. The computational efficiency of amplitude envelope obtained by Hilbert transform is 140 s·km⁻¹, and the computational efficiency of other indexes is 5 s·km⁻¹. The amplitude envelopes obtained by Hilbert transform in the subgrade sections and tunnel sections are the most sensitive, followed by scanning area. The number of intersections with the time axis in the bridge sections was the most sensitive, followed by the scanning area. The scanning area can adapt to different substructures such as subgrade, bridges and tunnels, with high comprehensive sensitivity.

The research can provide appropriate characteristic indexes from the high-frequency radar original signal to quantitatively evaluate ballast bed condition under different substructures.

The purpose of this paper is to examine whether competitor concentration relates to better customer acceptance of the firm’s offerings and better networking of the firm with competitors and government officials.

The research is conducted in the context of the transition economy of Vietnam, using a combination of methods. Qualitative interviews are followed by a survey of 199 small firms in Hanoi, Vietnam. Since competitor concentration is count data, Poisson regression is used to test the relationship between networking, customer acceptance, and competitor concentration.

The results show that locating in a competitor concentration area improves customer acceptance of the firm’s offerings and increases networking with competitors, while decreasing networking with government officials. Competitor concentration does not help improve firm performance.

A sample of 199 businesses in the food, furniture, and jewelry sectors in Hanoi may not be representative of all private businesses in Vietnam. The use of cross-sectional data could not establish causational relationships among variables.

Small firms in transition economies should be aware of the trade-offs between initial customer acceptance and negative consequences of being in a competitor concentrated area. Thus, once the firm’s offerings are generally accepted by customers, the firm may consider moving out of competitor concentration areas to expand and differentiate.

This paper points out that in the absence of effective market institutions, businesses want to be located near a concentration of similar firms as a means of gaining initial customer acceptance. This initial acceptance does not necessarily help firms improve business performance beyond the firm’s survival.

This study aims to understand whether business and political relations help emerging markets' SMEs to overcome the challenges posed by low institutionalization in their national and international expansion. It focuses on the role that these relations play in determining access to government funding and contracts and to market information and business-related knowledge.

The data were collected from 828 SMEs in Brazil and China. The data analysis was developed in two stages: the first stage was based on multivariate regression analyses using the ratio of sales outside the companies' region of origin divided by total sales as a dependent variable and the survey's answers as independent variables; outward sales were taken at two different levels – national and international – to consider: (1) the different stages in the national and international expansion process, and (2) the fragmented nature of domestic markets in both Brazil and China. The second stage was based on a stepwise multiple regression as the relative importance of the variables was not known beforehand and the objective was to rank them according to the managers' perceptions.

Informal institutions, in particular business and political relations, can help to reduce uncertainty and overcome some disadvantages associated with weak institutionalization. They do this by providing access to trusted distribution channels, improving the familiarity with different institutional environments and strengthening the management of supply chains and commercial strategies to serve markets outside their region. Also, SMEs in emerging markets getting access to private sources of funding, market knowledge and government contracts through business and political relations are in a better position to expand nationally and internationally.

The research shows that the domestic environment, in particular one with low levels of institutionalization, impacts negatively the national and international expansion of SMEs and, more importantly, how firms can use business and political relations to overcome the obstacles posed by this environment. The findings also have implications for theory, practice and policymaking.

Many markets are conceptualized as a stratified low- and middle-income “pyramid” of consumers. Emerging markets are sites of rapid consumer mobility, and thus the middle class there is connected to, and often supports, low-income relatives and employees. Therefore, this paper aims to establish that African income groups are not insular, but rather interrelated and have strong social ties reinforced with longstanding communal values, such as ubuntu.

Using a between-subjects experimental vignette design, the propensity of the middle class to cover low-income individuals on an insurance product was assessed.

Income strata are interrelated and can inform value propositions, which is demonstrated in this paper with insurance, where the middle class are willing to include others, depending on their social proximity, on their insurance cover.

The context for this study was personal home insurance; hence, the generalisability of the results is circumscribed. Other more tangible forms of cover, such as medical, funeral or educational insurance, may engender far stronger effects.

Marketers tend to view low- and middle-income consumers as independent. A view of their interrelation will change the design of many products and services, such as a service catered to the poor but targeted at their support networks. An example of such a service is insurance, which is traditionally hard to sell to the poor. A less atomistic approach to income strata could have implications for vicarious consumption, as well as a reconsideration of the disposable income of both groups.

The pyramid is an interconnected network of social and economic ties.

Given that several publicly announced international merger and acquisition deals have been abandoned in recent years, the purpose of this paper is to present a synthesis of influential articles that examine organizational characteristics of cross-border acquisition transactions. The synthesis is framed through general traits and resources, learning and prior acquisition experience, and top-level management and governance attributes. Specifically, the paper conceptualizes key organizational attributes influencing the propensity of cross-border negotiations, and the most common characteristics and post-deal effects by illustrating several case examples from around the world.

Owing to fairness and integrity principles of the literature survey studies, the paper adopts an exploratory review design to present a synthesis of several influential articles published in strategy, international business and corporate finance journals. Since case method and storytelling are the best qualitative approaches to conceptualizing extant theoretical contributions, a number of case examples—successful, delayed and abandoned—from around the world have been discussed by leveraging the case information from archival sources.

Drawing on resource-based view, organizational learning, upper echelons and agency theory perspectives, the paper underscores three observations. First, organizational characteristics such as firm age, firm size, ownership structure, slack resources, marketing resources, technological intensity, export intensity and business group affiliation have different impacts on the propensity of publicly announced cross-border deals. Second, firm’s prior acquisition experience and firm’s acquisition experience in the target country have positive or moderating effects on the success of a cross-border merger. Third, top-level management characteristics such as CEO foreign nationality and CEO international career experience, and governance characteristics such as board size, the number of independent directors and directors with overseas experience, have mixed effects on the incidence of cross-border acquisitions.

The paper puts forth several recommendations for top-level managers participating in cross-border acquisition negotiations, such as learning from peers in the same industry, learning from predecessors in the target country and learning from failure negotiations in the same industry and other industries.

Nested within the organizational, international business strategy and corporate finance literature, the paper presents a synthesis of influential publications that study organizational characteristics affecting the propensity of cross-border acquisitions. The cases discussed in this paper are unique examples from around the world.

The purpose of this study is to examine the relationship between positive emotion, self-efficacy, job satisfaction and turnover intention in the context of resource building during the socialization process of new faculty members, particularly in the context of the coronavirus disease 2019 (COVID-19) pandemic.

The study utilizes a quantitative research design and employs purposive sampling to obtain 554 valid questionnaires. The study analyzes the relationship between positive emotion, self-efficacy, job satisfaction and turnover intention and examines the influence of strategic human resource management (SHRM) on these variables.

The results of the study reveal that SHRM positively influences positive emotion and self-efficacy, which, in turn, positively impact job satisfaction. However, positive emotion is negatively related to turnover intention.

This study contributes to the existing literature on human resource management (HRM) by examining the impact of strategic HRM on the socialization process of new faculty members. The findings of the study have significant practical implications for the implementation of HRM in research-oriented universities.

The dynamism of competition in international markets requires managers to react accordingly and ensure the firm's survival and competitiveness. This study examines the impact of cognitive styles and dynamic managerial capabilities (DMC) on a firm's international performance and the mediating role of these capabilities in the relationship between cognitive styles and international performance.

This study adopts a quantitative cross-sectional research design, employing a sample of 306 firm owner-managers from exporting companies in Kosovo.

The findings suggest that managers' cognitive styles positively influence firm international performance, including their impact on DMC. Results also indicate that only managerial cognition mediates cognitive styles' effects on a firm's international performance, compared to managers' social capital.

In this study, the authors contribute to the literature by integrating cognitive styles with DMC in a transition country. Moreover, the authors demonstrate that DMC mediate the impact of cognitive styles on the firm international performance.

Hydroelectric power is widely used because it is environmental friendly, renewable and green. The cavitation is an inevitable phenomenon during the operation of hydro turbine, which is related to the efficiency and service life of the unit. This paper aims to discriminate the phenomenon of the incipient cavitation, prevent the early destruction and avoid the irreversible damage to hydro turbine.

The paper tries to find out the characteristics of cavitation entirely through a variety of features. The method comprises collection of the signals using a hydrophone, acceleration sensor and acoustic emission sensor; analyzing cavitation signal by using the way of wavelet time-frequency, peak factor and power spectral density; and comparing the different wavelet basis for analyzing signals and find the most suitable one.

The analyzed results show that the wavelet basis of morlet is more suitable for the cavitation signals. The hydrophone can distinguish the different operating conditions and discriminate the difference between the phenomenon of incipient cavitation and the other state of cavitation. The results show that when the hydrophone and acceleration sensors are used, the accuracy rate goes up to 75 per cent, which meets the requirements for the detection for incipient cavitation.

This paper focuses on finding the best sensor to discriminate the operating state of incipient cavitation to prevent early destruction.

The purpose of this paper is to focus on the development of highly efficient emission materials for light‐emitting diodes (LEDs).

The equilibrium geometries of silole‐based derivatives are optimised by means of DFT/B3LYP method with the 6‐31G(d) basis set in this paper. The geometries of single‐excitation are optimised using the ab initio configuration interaction with single excitations/6‐31G(d), the first singlet excited states and optical properties are calculated by using time‐dependent density‐functional theory based on the 6‐31G(d) basis set.

The highest occupied molecular orbital and lowest unoccupied molecular orbital suffer larger effects from the variation of the substituent groups of methyls and phenyls. The absorption wavelengths of all the cases are similar, but the emission wavelengths are significantly different.

Solid‐state stacking effect is not included in this paper.

In view of the application of silole‐based derivatives systems, the control of photophysical properties and electronic structures by structural modification is relevant to further molecular design.

This study aims to propose a numerical modeling procedure for response analysis of elastic body floating in water and submitted to regular waves. An equivalent simplified mechanical single-degree-of-freedom system allowing to reproduce the heave movements is first developed, then the obtained lumped characteristics are used for elastic analysis of the floating body in heave motion.

First, a two-dimensional numerical model of a rigid floating body in a wave tank is implemented under DualSPHysics, an open source computational fluid dynamics (CFD) code based on smoothed particle hydrodynamics method. Then, the obtained results are exploited to derive an equivalent mechanical mass-spring-damper model. Finally, estimated equivalent characteristics are used in a structural finite element modeling of the considered body assuming elastic behavior.

Obtained results concerning the floating body displacements are represented and validated using existing experimental data in the literature. Wave forces acting on the body are also evaluated. It was found that for regular waves, it is possible to replace the complex CFD refined model by an equivalent simplified mechanical system which makes easy the use of structural finite element analysis.

The originality of this work lies in the proposed procedure to evaluate the mechanical properties of the equivalent elastic system. This allows to couple two different software tools and to take advantages of their features.