Numerical study of subcooled and saturated flow boiling in the curved and helically coiled tubes in presence of phase change is one of the challenging area of CFD studies. In this paper, the CFD modeling of the nucleate and convective flow boiling in the small helically coiled tube at low vapor quality (up to the 18.93 percent) region is studied. A proper Eulerian-based mathematical model is used for interphase exchange forces and heat transfer between two phases in CFD modeling using Bulk boiling model. The results show that, the inner and the bottom wall of the helically coiled tube have the lowest and the highest heat transfer coefficient, respectively. The effect of change in coil diameter, helical pitch and tube diameter is investigated on the counters of vapor volume fraction. It is seen that at low vapor quality flows, the heat transfer coefficient is enhanced by decreasing in coil diameter, tube diameter and increasing in coil pitch of helically coiled tube.
This paper provides a comprehensive review of equity trading simulators, focusing on their performance in assuring pre-trade compliance and portfolio investment management. A systematic search was conducted that covered the period of January 2000 to May 2023 and used keywords related to equity trade simulators, portfolio management, pre-trade compliance, online trading, and artificial intelligence. Studies demonstrating the use of simulators and online platforms specific to portfolio investment management, written in English, and matching the specified query were included. Abstracts, commentaries, editorials, and studies unrelated to finance and investments were excluded. The data extraction process included data related to challenges in modern portfolio trading, online stock trading strategies, the utilization of deep learning, the features of equity trade simulators, and examples of equity trade simulators. A total of 32 studies were included in the systematic review and were approved for qualitative analysis. The challenges identified for portfolio trading included the subjective nature of the inputs, variations in the return distributions, the complexity of blending different investments, considerations of liquidity, trading illiquid securities, optimal portfolio execution, clustering and classification, the handling of special trading days, the real-time pricing of derivatives, and transaction cost models (TCMs). Portfolio optimization techniques have evolved to maximize portfolio returns and minimize risk through optimal asset allocation. Equity trade simulators have become vital tools for portfolio managers, enabling them to assess investment strategies, ensure pre-trade compliance, and mitigate risks. Through simulations, portfolio managers can test investment scenarios, identify potential hazards, and improve their decision-making process.
Local scour, a complex phenomenon in river flows around piers with movable beds, can damage bridge piers during high floods. Predicting scour depth accurately is vital for safety and economic reasons, especially for large bridges. This study using hydraulic flume laboratory experiments compared diamond, square, and elliptical pier models of different sizes under steady clear-water conditions considering different flow rates and discharge levels to identify the most efficient shape with less local scour. Local scour, a complex phenomenon in three-dimensional flow around piers in rivers with movable beds, can lead to detrimental effects on bridge piers due to high flood velocities. Accurate prediction of scour depth is crucial for economic and safety reasons, especially for large bridges with complex piers. Hydraulic engineers are keen on forecasting the equilibrium scour depth. To achieve this, laboratory testing compared diamond, square, and elliptical pier models under steady clear-water conditions to identify the most efficient pier shape with less local scour. This research provides valuable insights for optimizing pier design to enhance bridge stability and resilience against scour-induced risks. A variety of configurations, including different sizes and shapes of piers were experimented with in the flume using diamond, square, and elliptical shapes. The test results showed that the local scour depth around elliptical piers was around 29.16% less, and around diamond piers, it was approximately 16.05% less compared to the scour depth observed around square piers with the same dimensions. The researchers also observed distinct patterns of scouring around different pier shapes. Specifically, the square-shaped piers displayed the highest level of scouring depth, that is, 48 mm, followed by the diamond-shaped pier which experienced a scouring depth of 48 mm while the elliptical-shaped piers experienced the least amount of scouring depth, that is, 34 mm. The test results also demonstrated that pier size significantly influences scouring, with an increase in pier size from 3 × 3 cm2 to 5 × 5 cm2 leading to a rise in scour depth by 26.04%. Moreover, this study findings also elucidated that an increase in flow results in an increase of in scouring depth i.e., elevating the discharge from 0.0026 cumecs to 0.0029 cumecs led to a 28.13% increase in scouring depth for the identical pier size. These findings provide valuable insights into the hydraulic behavior of various pier shapes and can aid in the optimization of bridge design and hydraulic engineering practices. The investigations further revealed that local scouring is sensitive not only to pier dimensions but also to other critical parameters, including flow rate, time of exposure, and the size of a pier.
Optimizing Storage Location Assignment (SLA) is essential for improving warehouse operations, reducing operational costs, travel distances and picking times. The effectiveness of the optimization process should be evaluated. This study introduces a novel, generalized objective function tailored to optimize SLA through integration with a Genetic Algorithm. The method incorporates key parameters such as item order frequency, storage grouping, and proximity of items frequently ordered together. Using simulation tools, this research models a picker-to-part system in a warehouse environment characterized by complex storage constraints, varying item demands and family-grouping criteria. The study explores four scenarios with distinct parameter weightings to analyze their impact on SLA. Contrary to other research that focuses on frequency-based assignment, this article presents a novel framework for designing SLA using key parameters. The study proves that it is advantageous to deviate from a frequency-based assignment, as considering other key parameters to determine the layout can lead to more favorable operations. The findings reveal that adjusting the parameter weightings enables effective SLA customization based on warehouse operational characteristics. Scenario-based analyses demonstrated significant reductions in travel distances during order picking tasks, particularly in scenarios prioritizing ordered-together proximity and group storage. Visual layouts and picking route evaluations highlighted the benefits of balancing frequency-based arrangements with grouping strategies. The study validates the utility of a tailored generalized objective function for SLA optimization. Scenario-based evaluations underscore the importance of fine-tuning SLA strategies to align with specific operational demands, paving the way for more efficient order picking and overall warehouse management.
Cyclically, the debate on Keynes’ economic policies reemerge. The economic impact of the pandemic caused by COVID-19 has relaunched the discussion about the importance of Keynesian policies, the multipliers effects, and their impact on stimulating economies. This paper aims to analyze the importance and relevance of the Keynesian multiplier before the pandemic, in a period without experiencing exceptional aggregate shocks. The main focus of the research is to examine the shortcomings of the public investment multiplier, which plays a central role in Keynesian theory. Despite the undeniable relevance of the concept, the issue is to understand the extent to which the multiplier is still relevant in specific contexts. The research presents empirical evidence which suggests that the effects of public investment depend on structural characteristics of economies specifically trade liberalization, the dimension of internal markets, the question of countries having the freedom to issue their currency, and the issue of currencies being accepted as an international reserve. A sample of 35 OECD countries was used for the period 2010–2018. The Keynesian public investment multiplier was calculated for several countries and the obtained values were related to various correlations carried out to assess the relationship between public investment, national income, and specific characteristics of the economies to which the multipliers are sensitive. The results obtained contrast in terms of short-term and long-term impacts so, is at least dubious, that one can rely on Keynesian public policies to boost economies at least in the absence of substantial shocks to aggregate demand.
Background and introduction: The East and Southeast Asian newly industrialized economies have shown spectacular economic development by their export-oriented development policies during recent decades, which resulted in not only economic wealth but enabled them to be technology exporters and investors. Their products, their flagship brands today are well-known and recognized throughout the world. It is not surprising that the Hungarian government—by its Hungarian Eastern Opening strategy—intended to focus on these economies, even though that with most of them there were intensive and broad co-operation in the fields of business, investment, culture, education and tourism. The new strategy gave a focus on increasing the diplomatic and trade relationship with the wider region, new embassies and trade representation offices were opened or re-opened in several locations with the view of intensifying the business and the people-to-people contacts. Even though the pandemic of Covid 19 and the energy crisis caused disruption in international trade, it can be said the trade and investment relations with these economies have still been growing, especially on the import side. The prospects of the growth of Hungarian exports to these destinations are modest which is hindered by the huge geographic distance, the peculiar consumer preferences, the merely different market conditions and the sharp competition. Objective: The aim of this paper to illustrate by statistical figures the state of the trade and investment relations between Hungary and the Republic of Korea, Taiwan, Singapore and Thailand. Methodology: Bibliographic and data analysis, focusing on the relevant international and Hungarian literature and databases, especially the trade and investment statistics of the Hungarian Central Statistical Office (HCSO/KSH).
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