Search results

This paper aims to obtain the evolution law of dynamic performance of CR400BF electric multiple unit (EMU).

Using the dynamic simulation based on field test, stiffness of rotary arm nodes and damping coefficient of anti-hunting dampers were tested. Stiffness, damping coefficient, friction coefficient, track gauge were taken as random variables, the stochastic dynamics simulation method was constructed and applied to research the evolution law with running mileage of dynamic index of CR400BF EMU.

The results showed that stiffness and damping coefficient subjected to normal distribution, the mean and variance were computed and the evolution law of stiffness and damping coefficient with running mileage was obtained.

Firstly, based on the field test we found that stiffness of rotary arm nodes and damping coefficient of anti-hunting dampers subjected to normal distribution, and the evolution law of stiffness and damping coefficient with running mileage was proposed. Secondly stiffness, damping coefficient, friction coefficient, track gauge were taken as random variables, the stochastic dynamics simulation method was constructed and applied to the research to the evolution law with running mileage of dynamic index of CR400BF EMU.

Cannabis as a recreational drug is prohibited in Nigeria. Consequently, the open use of cannabis attracts both formal and informal sanctions. As such, there is much stigma on users' faces across social spaces. This has led to innovations in drug use. Recently, non-medical use of tramadol has been rising across each of the gender categories. This study aims to understand (1) tramadol use prompts, (2) the sudden surge in gendered recreational use of tramadol and (3) the gendered challenges of recreational tramadol use among Nigerian university students.

Data were collected between December 2021 and October 2022. The researcher conducted 20 semi-structured interviews, with participants chosen purposefully from acquaintances and others selected through chain referral. The selection criteria included knowledge of a particular tramadol tablet and willingness to participate. This study got ethical approval from the Anambra State Ministry of Health (Ref: MH/AWK/M/321/354) and oral consent was obtained before the interviews. The participants were assured of confidentiality. The interviews were conducted in English (the formal Nigerian language) and lasted between 30 and 65 min. The data collected were transcribed and coded manually, and themes generated.

Findings suggest that peer pressures accounted for entry-level drug use. However, cannabis-related stigma is attributed to the surge in tramadol use across gender categories. Furthermore, academic pressure and sexuality are major reasons for tramadol use. The challenges associated with tramadol use include headaches and addiction.

This study, to the best of the author’s knowledge, presents alternative data on the surge in tramadol use among Nigerian university students.

One of the major challenges in the design of thermal equipment is to minimize the entropy production and enhance the thermal dissipation rate for improving energy efficiency of the devices. In several industrial applications, the structure of thermal device is cylindrical shape. In this regard, this paper aims to explore the impact of isothermal cylindrical solid block on nanofluid (Ag – H₂O) convective flow and entropy generation in a cylindrical annular chamber subjected to different thermal conditions. Furthermore, the present study also addresses the structural impact of cylindrical solid block placed at the center of annular domain.

The alternating direction implicit and successive over relaxation techniques are used in the current investigation to solve the coupled partial differential equations. Furthermore, estimation of average Nusselt number and total entropy generation involves integration and is achieved by Simpson and Trapezoidal’s rules, respectively. Mesh independence checks have been carried out to ensure the accuracy of numerical results.

Computations have been performed to analyze the simultaneous multiple influences, such as different thermal conditions, size and aspect ratio of the hot obstacle, Rayleigh number and nanoparticle shape on buoyancy-driven nanoliquid movement, heat dissipation, irreversibility distribution, cup-mixing temperature and performance evaluation criteria in an annular chamber. The computational results reveal that the nanoparticle shape and obstacle size produce conducive situation for increasing system’s thermal efficiency. Furthermore, utilization of nonspherical shaped nanoparticles enhances the heat transfer rate with minimum entropy generation in the enclosure. Also, greater performance evaluation criteria has been noticed for larger obstacle for both uniform and nonuniform heating.

The current numerical investigation can be extended to further explore the thermal performance with different positions of solid obstacle, inclination angles, by applying Lorentz force, internal heat generation and so on numerically or experimentally.

A pioneering numerical investigation on the structural influence of hot solid block on the convective nanofluid flow, energy transport and entropy production in an annular space has been analyzed. The results in the present study are novel, related to various modern industrial applications. These results could be used as a firsthand information for the design engineers to obtain highly efficient thermal systems.

The objective of this study is to investigate the impact of longitudinal forces on extreme-long heavy-haul trains, providing new insights and methods for their design and operation, thereby enhancing safety, operational efficiency and track system design.

A longitudinal dynamics simulation model of the super long heavy haul train was established and verified by the braking test data of 30,000 t heavy-haul combination train on the long and steep down grade of Daqing Line. The simulation model was used to analyze the influence of factors on the longitudinal force of super long heavy haul train.

Under normal conditions, the formation length of extreme-long heavy-haul combined train has a small effect on the maximum longitudinal coupler force under full service braking and emergency braking on the straight line. The slope difference of the long and steep down grade has a great impact on the maximum longitudinal coupler force of the extreme-long heavy-haul trains. Under the condition that the longitudinal force does not exceed the safety limit of 2,250 kN under full service braking at the speed of 60 km/h the maximum allowable slope difference of long and steep down grade for 40,000 t super long heavy-haul combined trains is 13‰, and that of 100,000 t is only 5‰.

The results will provide important theoretical basis and practical guidance for further improving the transportation efficiency and safety of extreme-long heavy-haul trains.

Trade relations between China and the USA have been marked by conflict, especially since China’s membership in the World Trade Organization (WTO). These conflicts have been analyzed from a variety of perspectives, including the loss of jobs in the USA due to Chinese imports, competition in high technology sectors and the balance of trade. Conceptual frameworks have employed models of domestic differences as well as models of international power distribution. Among domestic differences examined are the existence of state-owned enterprises in China compared to the domination of the USA economy by private firms, the large role of the Communist Party in China and the influence of labor and environmental and labor groups in the USA. Power distribution theories focus on the systemic effects of the distribution of power on trade openness and on the pattern of intra-bloc versus between-bloc trade. This paper aims to examine the role of macroeconomic policy factors in China and the USA, in particular, the role of national patterns of savings, investment and consumption (both private and government). The paper concludes that insofar as the balance of trade is an important component of the trade conflict, domestic macroeconomic factors continue to be important. The resolution of the conflict will have to take into account the respective macroeconomic policies of China and the USA.

The design is an analytic case study of US–China trade relations with a particular focus on the balance of trade. The conceptual framework employed involves an analysis of macroeconomic policy categories, especially the overall pattern of savings (household, firm and government), investment and consumption. Process tracing over time since China's membership in the WTO is carried out with an eye toward the relationship between the balance of trade and macroeconomic policy.

The main findings are that there is a strong relation between the respective macroeconomic policies of the USA and China and their trade relations. The domestic political economy of the USA encourages consumption and a low rate of savings. The opposite is true of China where household income is low by design and national savings are high. China depends on the USA to consume what is not consumed domestically. The USA depends on Chinese imports for additional consumption encouraged by its low rate of savings. The two economies are locked in a mutual dependence.

Key research implications are that there should be more focus on domestic macroeconomic policies since these are the root causes of the trade imbalance. This is not to say that trade frictions centering on jobs, subsidies and competition in high technology are unimportant. However, without the resolution of differences in the management of macroeconomic policies, trade conflicts between the USA and China will continue.

Practical implications are huge, in some ways much more important than the academic implications. Macroeconomic policy differences in savings, investment, government spending, taxation and infrastructure are important. Furthermore, there are available tools in both China and the USA to manage the macroeconomy, particularly, monetary and fiscal policy.

One implication of this paper is that satisfaction or dissatisfaction of workers is dependent on income distribution which in turn affects trade. Treatment of people in different socioeconomic categories, such as the elderly, the young, and those at working age are a function of macroeconomic policies.

Many people have written about macroeconomics. It is a conventional subfield of economics. The originality of this paper lies in its advocacy of a shift of focus and attention and in the argument that traditional macroeconomics is related to trade. Despite its importance, macroeconomics has not been the center of attention for most political scientists, though economists have made it more central.

This study explores the organisational dynamics in a change process across work units in a Swedish municipality. The purpose of this study is to understand how and why co-creation unfolds during efforts to bring different units into one united work unit.

A qualitative longitudinal study was designed using data triangulation for eight months, comprising written reflection texts, meeting protocols and interviews. This study is based on a back-and-forth inductive and abductive grounded theory analysis.

The main results of this study indicate that there was friction in the co-creation process between units, between the members of the change group and supervisors, as well as friction within the change group. Further, the results indicate that communications, relations, supervisor support and governing strategies clashed with work routines and methods, work cultures, roles and responsibilities and that the units had differing views of the needs of the intended target group. This thereby challenged the propensity for change which, in turn, may have limited developmental learning at a workplace and organisational level.

Working across units to find common and new paths and work methods for labour market inclusion proved to be challenging because of contextual circumstances. Crossing and merging organisational boundaries through co-creation processes was demanding because of new expectations from the organisation, as it shifted towards trust-based governance in conjunction with working during a pandemic when social interactions were restricted to digital communication channels.

This paper aims to examine the prevailing Rohingya refugee crisis from political and humanitarian perspectives and explores the political and humanitarian aspects of the Rohingya refugee crisis.

Relevant literature has been reviewed for conceptual understanding. This study is descriptive and qualitative in nature and based on secondary sources of data.

The main causes of the Rohingya crisis such as political and humanitarian aspects. Issues such as discrimination and homelessness, and national security concerns that regional politics scapegoated the Rohingya to exacerbate regional tensions. Moreover, armed conflicts, political radicalization, security concerns, human rights violations and low media attention compared to other displaced families have made the future of the Rohingyas very uncertain.

The Rohingya crisis has far-reaching implications for domestic and regional politics as well as for relations with major world powers. In the context of regional security and geopolitics, this study provides insight into the polarization and politicization of the Rohingya minority.

This research offers a vital exploration of the Rohingya refugee crisis, delving into its multifaceted political and humanitarian dimensions, contributing fresh insights to address a pressing global concern.

The purpose of this paper is to explore the scope for action of local human resource managers, who are employed in foreign subsidiaries of multinational companies (MNCs), for implementing training activities. These managers are situated in relationships to headquarters and the local environment. Related to this is the question whether MNCs contribute to the local skill base by implementing training activities or whether they exploit the existing skill formation system.

This study focusses on German subsidiaries of MNCs with headquarters in the USA and the UK, France, China and Japan. The study is based on 107 expert interviews with subsidiary managers and representatives of local stakeholder organisations, such as educational organisations, chambers, economic promotion agencies and governmental bodies in Germany.

The study reveals that headquarters introduce general schemes for training. In addition to these MNC-internal trainings, local managers use their information advantage over headquarters to implement dual training activities.

The training activities of subsidiaries are dependent on the institutional settings of the host country.

Albeit dual training activities are laborious and tie the local managers down for the medium and long term, the future need of the subsidiary for adequately skilled workforce prompts local managers’ engagement in implementing dual training activities.

Subsidiaries contribute to the local skill base and do not act in a free-rider position, at least in the German variety of capitalism.

The study deepens insights on distanced relations within and how subsidiaries generate scope for action by using this kind of relationships.

National cultures significantly explain cross-country differences in the relation between asset growth and stock returns. Motivated by the notion that managers in individualistic and low uncertainty-avoiding cultures have a higher tendency to overinvest, this study aims to show that the negative relation between asset growth and stock returns is stronger in countries with such cultural features. Once the researchers control for cultural dimensions, proxies associated with the q-theory, limits-to-arbitrage, corporate governance, investor protection and accounting quality provide no incremental power for the relation between asset growth and stock returns across countries. Evidence of this study highlights the importance of the overinvestment hypothesis in explaining the asset growth anomaly around the world.

The authors explore the hypothesis that some movements in commodity prices are anticipated (news shocks) and can trigger aggregate fluctuations in small open emerging economies. This paper aims to discuss the aforementioned objective.

The authors build a multi-sector dynamic stochastic general equilibrium model with endogenous commodity production. There are five exogenous processes: a country-specific interest rate shock that responds to commodity price fluctuations, a productivity (TFP) shock for each sector and a commodity price shock. Both TFP and commodity price shocks are composed of unanticipated and anticipated components.

The authors show that news shocks to commodity prices lead to higher output, investment and consumption, and a countercyclical movement in the trade-balance-to-output ratio. The authors also show that commodity price news shocks explain about 24% of output aggregate fluctuations in the small open economy.

Given the importance of both anticipated and unanticipated commodity price shocks, policymakers should pay attention to developments in commodity markets when designing policies to attenuate the business cycles. Future research should investigate the design of optimal fiscal and monetary policies in SOE subject to news shocks in commodity prices.

This paper contributes to the knowledge of the sources of fluctuations in emerging economies highlighting the importance of a new source: news shocks in commodity prices.