Stasys Dailydka

Bio: Stasys Dailydka is an academic researcher from Vilnius Gediminas Technical University. The author has contributed to research in topics: Competitive intelligence & Diesel fuel. The author has an hindex of 9, co-authored 29 publications receiving 218 citations.

An analytical mathematical method for calculation of the dynamic wheel-rail impact force caused by wheel flat

Abstract: The simplified method to determine a vertical impact force of wheel with flat and rail interaction is presented in this article. The presented simplified method can be used to identify maximum contact force and its distribution in the contact length between the damaged wheel and the rail. The vertical impact force depends on geometrical parameters of the rail and wheel with flat, speed of vehicle and the angle of deviation of rail. This article demonstrates the influence of wheel with flat geometrical parameters, speed of vehicle to maximum contact force and its distribution in the contact zone. The obtained values of the simplified method for determination of a vertical contact force are compared with the results obtained from field measurements.

Determination of the dynamic characteristics of freight wagons with various bogie

Abstract: In most cases, dynamic characteristics determine the wagon maintenance cycle, traffic safety, reliability and durability performance. The main dynamic indicators include the vertical Kvd and horizontal Khd dynamic coefficients as well as the stability coefficient Ks, which determines the wheel flange resistance to derailment. The article compares dynamic indications for three different types of bogies. There were no tangible differences observed for all the three different types of bogies running at a speed of 40 to 120 km/h on a direct tangent rail section. Nevertheless, there is a realistic potential to improve the dynamic indicators of a freight wagon by rationalising suspension unit parameters.

Modelling the interaction between railway wheel and rail

Abstract: The article presents a mathematical model for assessing the real operating conditions of railway rolling stock, taking into account the situations when the wheel loses contact with rail. The obtained amplitudinal fluctuation characteristics depend on the set roughness function and the running speed of the wheel. When calculating dynamic processes, the contact between wheel and rail should be considered unstable. With the increase of speed, the impact of this instability increases.

The dynamic behaviour of a wheel flat of a railway vehicle and rail irregularities

Abstract: The article examines a mathematical model for the system ‘Railway Vehicle Wheel–Track’ that allows examining the interaction between a wheel flat and a rail in the vertical plane The dynamics of the railway track is described using the finite element method while that of the soil and vehicle is expressed applying discrete elements The model is used for assessing physical and mechanical properties, the roughness of the wheel, rail surface and their geometry The analysis of the dynamic system ‘Railway Vehicle Wheel–Track’ has been conducted In accordance with the revised method, forces arising from contact between the wheel flat and the rail are possible to be determined in a more precise way The article presents and analyses the results of a mathematical experiment on this system

The criteria for identifying the quality of passengers’ transportation by railway and their ranking using AHP method

Abstract: Passengers’ transportation by rail involving various interested groups, such as managers, service staff and passengers, is a complicated process. Decision‐making persons, organizing railway trips should take into account the interests, needs and possibilities of these particular groups. The solution to some problems associated with passengers’ transportation by rail depends on the experience and qualification of decision‐makers, people who are responsible for the effectiveness of this work. To increase the quality of railway trips, the interested parties, groups of people mentioned above, should coordinate their actions, cooperate with each other in solving the problems and exchange relevant information. Therefore, the increasing quality of passenger transportation is a complicated issue, requiring good professional skills based on knowledge, practical experience, high intellect and new ideas of all the people involved in this process. The current paper presents a diagram showing passenger's tran...

Explaining The Variation In Reit Capital Structure: The Role Of Asset Liquidation Value

Abstract: Real Estate Investment Trusts (REITs) with different property type focuses exhibit significant variation in capital structure. Average leverage ranges from a low of forty percent for industrial REITs to a high of sixty-one percent for hotel REITs. Debt maturity ranges from seventy-four months for office REITs to 105 months for hotel REITs. The extent of this variation is surprising because all REITS share common tax and governance attributes. In this paper, we explore the systematic variation in capital structure by REIT type. We first examine how well the traditional corporate finance explanations for variations in capital structure explain the observed variations within the REIT sector. Myers (1977) and Hart (1993) show that changes in leverage and the mix of long- and short-term debt can alter the incentives of managers and help resolve the over- and under-investment problems identified in the agency and corporate governance literature. Other theoretical papers have focused on the problems associated with asymmetric information between managers and investors (Diamond, 1991 and Titman, 1992) and the use of debt to signal the quality of the firm and its investment prospects. Several recent empirical studies have modeled a firmis capital structure choices (Datta, Iskandar-Datta and Raman, 2005, Johnson, 2003 and Barclay, Marx and Smith, 2003) that support these theories. We estimate a simultaneous equation model similar to Johnsonis (2003) for a panel data set of REITs and find that the ratio of market-to-book value (traditionally viewed as a proxy for firm growth opportunities) and firm size are significant in explaining both the leverage and debt maturity equations and have signs consistent with their hypothesized effects. We then extend the Johnson (2003) model to include measures of the liquidation value of the underlying collateral. Shleifer and Vishny (1992) argue that variations in the liquidation value of the assets across different industries can help explain the observed variations in capital structure by industry and time. Briefly, Shleifer and Vishny argue that firms in industries where assets have high liquidation values will use higher leverage and longer maturity debt. This liquidation value theory has been hard to test empirically because of difficulty in measuring liquidation values and consequently liquidation value has not been included in previous studies of firm capital structure. However, the REIT sector provides a unique opportunity to test this theory because REITs typically concentrate in a particular type of real estate asset and different types of real estate assets exhibit significant differences in liquidity and redeployability. We use two different quantitative measures of liquidity as well as a more subjective rank ordering of property types by liquidation value to extend the model of capital structure. First, because short-term leases provide the landlord an option to reorient the current property, we add the average lease maturity to the system of equations for leverage and debt maturity. Consistent with Shleifer and Vishnyis (1992) hypothesis, we find that REITs with shorter maturity lease structures use lower leverage and shorter maturity debt. Second, we measure liquidity by the average recovery on defaulted Commercial Mortgage-backed Securities (CMBS) loans collateralized by different property types. Highly liquid, easily redeployed assets should retain their value better than less liquid assets and thus result in lower average losses for lenders when a default occurs. When Johnsonis model is extended using this categorical variable, it provides further evidence that liquidation value influences capital structure. Finally, we extend the concept of liquidation value to include more qualitative measures of liquidity such as zoning flexibility and physical redeployability. We rank order the five major REIT property types using all four dimensions of liquidity and identify industrial and residential REITs as having the most liquid assets and office and retail REITs as having the least liquid assets. We re-estimate the model using property type indicators as proxies for liquidation value and find evidence consistent with the hypothesis that firms with highly liquid assets use more leverage and longer debt maturity. We conclude that the liquidity of the underlying assets significantly influences managementis choice of capital structure within the REIT sector.

Analysis of energy efficiency in China's transportation sector

Abstract: Using a global meta-frontier approach, this paper analyzes energy efficiency and the savings potential in China's transportation sector from 2006 to 2014 from the perspectives of technological progress, technology gaps, and management efficiency. The results show that energy efficiency in China's transportation sector first decreased from 2006 to 2010, mainly due to a decline in management efficiency and an expansion of the regional technology gap. The energy efficiency then increased from 2011 to 2014 when management efficiency and the regional technology gap stabilized. The energy efficiency in China's transportation sector shows spatial differences, suggesting that the focus of future work on China's provincial transportation sectors should be quite varied. Most provinces in eastern China should commit to upgrading their management efficiency, while most provinces in central and western China should focus on both upgrading their management efficiency and narrowing the regional technology gap.

Research On the Quality of Passenger Transportation By Railway

Abstract: The transportation of passengers by railroads is a dynamic process because setting, wherein the process takes place, undergoes continuous changes observed at technical, technological and transportation process planning levels. Every passenger has different needs and aims and can afford different possibilities. Therefore, the conception of quality differs in each individual case. In order to be able to plan a railway trip process in a proper manner, it is important to become familiarized with passenger needs and preferences and eliminate any existing deficiencies. To this end, it is reasonable to conduct passenger surveys. The paper provides an affinity diagram of railway transportation quality factors, the elements whereof correspond to the structure of the survey questionnaire. For determining the level of the quantitative significance (weight) of indicators, there was applied the method of Analytic Hierarchy Process (AHP) developed and introduced by the American scientist T. Saaty. The scope of...

Wheel flat can cause or exacerbate wheel polygonization

Abstract: Wheel flat is a common local defect occurring to railway wheels. The relevant standards have specified the operational limits for wheel flats in terms of the length. However, in the actual operatio...