固体を含む水理学的問題に対するマクロおよびメソスコピックな数値モデルの適用

国立大学法人長岡技術科学大

Thermal free-surface immersed-boundary lattice Boltzmann method for free surface flows with a liquid-solid phase transition

This paper reports on the progress of the liquid-solid phase transition modeling of water in open channel flow by using the lattice Boltzmann method with the immersed boundary modification. The phase transition in a fluid flow has a moving interface between the liquid and solid state, which leads complicated treatments in existing numerical models. By applying the immersed boundary modification in the lattice Boltzmann method and the non-iterative enthalpy approach for the separation of the states, the moving boundary of the melting or solidification front is solved without any difficulty. The ice bed and the submerged ice cover under dynamic flow conditions is exercised to demonstrate the model performance. The model is extremely suitable in the formulation in terms of its simple and compact framework extendable to any dimensions

PERCEPTIONS OF QUALITY AND EXPECTATIONS OF HOTEL SERVICES: Case study Mongolian 4,5 star hotels

Mongolia’s tourism industry has fully recovered after the COVID-19 pandemic, with an increase in foreign tourists. New international hotel chains are also opening and providing services. Mongolia has started to classify hotels by star system according to the new standard adopted in 1998. The Mongolian Standard “Hotel Service Quality Rating and Basic Requirements” MNS 5927:2008, which regulates hotel business activities in the laws, regulations, programs, plans, resolutions and orders in force in the Mongolian Tourism Industry, is the only legal document and national rating system for determining service quality. This study covered 4 and 5-star hotels that meet the Mongolian Standard “Hotel Service Quality Rating and Basic Requirements” MNS 5927:2008. This research assessed the expectations and perceptions of service quality in Mongolia’s four and five stars hotels by applying a modified version of the SERVQUAL model. A convenient sample of 270 guests drawn from six 4, 5 star hotels was used in the analytical stage. It also examined the relationship between overall satisfaction levels and the five service quality dimensions reliability, responsiveness, assurance, empathy end tangibility. The findings indicated, as a whole that the hotel customers’ perceptions of service quality provided by the hotel industry were lower than their expectations and the gap between customers’ expectations and perceptions were significant. Keywords: guest satisfaction, service quality, guest expectation, guest perception DOI: 10.7176/JEP/16-5-13 Publication date: May 30th 202

The Potential Implications of Mongolia Joining BRICS+ Nations: A Comprehensive Analysis

In the contemporary epoch of globalization, the expeditious growth of emerging economies is precipitating novel opportunities for transnational cooperation and investment. The establishment of regional economic cooperation and integration frameworks by nation-states is augmenting trade and investment flows, exemplified by the investment-driven collaboration among BRICS member states and contiguous countries. Mongolia, endowed with an abundance of mineral resources, is actively pursuing accelerated socio-economic development objectives and bolstering its international policy, affirming its role as a participant in regional and global development. Furthermore, this paper undertakes a comprehensive examination of the status, expectations, and potential implications of Mongolia's accession to this current ten-member organisation. Through a critical analysis of the geopolitical and economic dynamics at play, this research aims to elucidate the transformative potential of Mongolia's integration into the BRICS+ framework, and its concomitant impact on regional economic cooperation, global governance, and the nation's socio-economic trajectory. This study will, therefore, determine why Mongolia should be a new member of the BRICS+ bloc. Keywords: BRICS+, Mongolia, macroeconomics, policy, currency DOI: 10.7176/JEP/16-1-12 Publication date: January 30th 202

Introduction to Proceedings of ISCSET 2022

For the first time in its history, the proceedings of the 11th International Symposium on Computer Science, Computer Engineering and Educational Technologies (ISCSET-2022) is published in a special issue of the Embedded Self-Organizing Systems journal of the Chemnitz University of Technolog

Effectiveness of Transformative Learning Theory in Physics Laboratories of Physics Students of Mongolian National University of Education(MNUE)

As part of the conceptual reform of the curriculum, the orientation of changes in content, teaching methods, and evaluation are defined by the principles of “Simplifying Content, Amplifying Methodology, and Amplifying Process Evaluation”. In this study, we examined how Transformative Learning Theory can be applied to enhance students\u27 scientific inquiry abilities in the "Practicum of Physics Experiment" course within the MNUE’s Physics Teacher Training Program. The discussion focuses on developing a teaching and learning method for the physics laboratory, rooted in Transformative Learning Theory, to improve the experimental proficiency of Physics students at MNUE. The findings of the experimental study demonstrate a notable enhancement in students\u27 initial average score across various domains. Specifically, there was an increase of 2.57 points in conceptual knowledge, 2.61 points in planning skills, 2.75 points in the skills related to conducting experiments and collecting data, and 2.31 points in data analysis skills. When the students\u27 laboratory performance evaluation results were analyzed using a t-test, the results showed t = -43.096 and p = 0.001, indicating a statistically significant differences between pre and post-test

THE IMPACT OF DIESEL BUS EMISSIONS ON AIR POLLUTION IN ULAANBAATAR AND ATTEMPT TO REDUCE IT

The advantages of diesel engines have led it to become the only solution for heavy-duty vehicles (HDV), including city buses. Exhaust gas from diesel engines (EG) is a common environmental pollutant and carcinogenic to human health. The paper presents the results of measuring the emissions of city buses running on high sulfur fuel with and without diesel particulate filter (DPF). The study was conducted in real traffic conditions along the regular route of the city of Ulaanbaatar. The measurements were carried out using the HORIBA PEMS (Portable Emissions Measurement System) and the gravimetric method. The measured data was used to determine the actual emission levels from city buses. The actual particulate matter (PM) emissions from city buses were determined during the warm and cold seasons on a daily basis. It is found that a bus with average daily mileage of 242 km emits average of 166.155 g of PM into the atmosphere per day. This fluctuates depending on the season - 141.3 g in summer and 175.8 g in winter. The actual PM emissions of a city bus is 0.6866 g/km. The NOx concentration in the exhaust gases is 1410.94 ppm on average. As a result of 6 months of measurements, a total of 346.651 kg of soot was collected from 24 buses. Innovation: Actual on-road emissions from Ulaanbaatar buses and a cassette-type DPF system with “active” outside the bus regeneration, that can reduce conventional diesel engine PM emissions by up to 90% regardless of the sulfur content of the fuels