Experimental Study of Prestressed Concrete Track Slab at Railroad Crossings

Currently, the prestressed concrete track slabs are testing installed at the field to replace the reinforced concrete track slabs at railroad crossings in Vietnam. Prestressed concrete track slabs used for 1000 mm gauge. The dimensions of each slab were designed with a length, width, and height of 2.5 m, 1.0 m, and 0.33m, respectively. This paper presents experimental measurements to analyze the behavior of the prestressed concrete track slab at railroad crossings under the action of train and truck dynamic load. Experiment measurements were implemented at the site. Eight strain gauges were mounted at three sections of the track slab to measure the deformation. HL-93 truck load and TY-7E train load were used in the test. The results show the eccentricity of the gravity center point of the prestressed wires to the centroidal axis of the transformed area. The deviation ratio between experimental and theoretical results is from 0.88% ÷ 1.25%. These results can be used to optimize the design process and limit cracks. In addition, tensile and compressive stresses in slabs are smaller than the allowable values. The results show that this track slab meets the requirements of durability and strength under the action of train and truck dynamic load

Experimental Study of Prestressed Concrete Track Slab at Railroad Crossings

Currently, the prestressed concrete track slabs are testing installed at the field to replace the reinforced concrete track slabs at railroad crossings in Vietnam. Prestressed concrete track slabs used for 1000 mm gauge. The dimensions of each slab were designed with a length, width, and height of 2.5 m, 1.0 m, and 0.33m, respectively. This paper presents experimental measurements to analyze the behavior of the prestressed concrete track slab at railroad crossings under the action of train and truck dynamic load. Experiment measurements were implemented at the site. Eight strain gauges were mounted at three sections of the track slab to measure the deformation. HL-93 truck load and TY-7E train load were used in the test. The results show the eccentricity of the gravity center point of the prestressed wires to the centroidal axis of the transformed area. The deviation ratio between experimental and theoretical results is from 0.88% ÷ 1.25%. These results can be used to optimize the design process and limit cracks. In addition, tensile and compressive stresses in slabs are smaller than the allowable values. The results show that this track slab meets the requirements of durability and strength under the action of train and truck dynamic load

仮想空間移動課題における自己の空間的位置更新に関わる事象関連電位のsLORETA法による電流源密度解析

富山大学・富生命博甲第54号・NGUYEN MINH HAI・2014/03/21Frontiers in behavioral neuroscience,2014,Vol.8,Article66,doi:10.3389/fnbeh.2014.00066に掲載。出版社版はhttp://journal.frontiersin.org/Journal/10.3389/fnbeh.2014.00066/（オープンアクセス）富山大

Behavior of monolithic prestressed concrete slab track at highway-railway grade crossings

Highway-railway grade crossings are an important part of the transportation system. It allows two types of vehicles to operate in the same areas. Researchers have previously studied the grade crossings, but research on the monolithic prestressed concrete slab (PSCS) track at grade crossings for 1,000mm gauge is limited. At present, there are many types of grade crossing structures that are using in Vietnam. However, these structures still have many disadvantages in the operation process. A new structure type of grade crossing for PSCS is proposed to apply for the 1,000 mm gauge to overcome the main disadvantages of existing structural types. This paper presents test production and experimental measurements to analyze the behavior of PSCS. Test samples of monolithic PSCS were produced in factory. Measurement experiments were conducted in the laboratory. The results of the manufacturing and testing process presented in this paper show that this structure completely meets the criteria of stability and durability under the effect of test loads

A Study on Derailment at Railway Turnout Using the Multi-body Dynamics Simulation

In this study, the locomotive and the turnout were simulated with three-dimensional models. The purpose of this study is prediction the derailment phenomenon of the locomotive running on the turnout in Vietnam. Multi-body simulations were implemented by SIMPACK software to determine the derailment coefficient, the wheel unloading factor, and the lateral force. The interaction between the locomotive and the track structure at turnout was considered unified. The derailment coefficient, the wheel unloading factor, and the lateral force were calculated for locomotive-D19E at turnout (tg0.15) for 1000 mm gauge according to QCVN 18:2011/BGTVT, EN 14363:2016, and TCVN 8784:2011. The derailment coefficient, the wheel unloading factor, and the lateral force for the locomotive at max speed V=27.8 km/h are 0.94, 0.61, and 67.46 kN, respectively. These results show that the locomotive will not derail when it passes the turnout at a speed V 27.8 km/h

SHEDDING TO GROW: THE COMING DOI MOI 2.0 IN VIETNAM’S FOREIGN POLICY

Purpose of the study: The purpose of this study is to revisit the characteristics of Vietnam’s foreign policy since its renovation in 1986, also known as Doi Moi, and explore its future trajectory in the coming decades. Methodology: This study employs a well-established analytical framework relying on the two-level game theory in foreign policy analysis which denotes that a state’s foreign policy is shaped by both external and domestic factors. Primary data are collected from a wide range of trusted resources and databases and communications of the authors with Vietnamese veteran diplomats and foreign policymakers. Main finding: This article finds that three decades since the launching of Doi Moi in 1986, fundamental principles of Vietnam’s foreign policy remains intact. Because both domestic and external foundations for the initial stage of renovation have fundamentally been replaced by new contexts, Hanoi will likely move towards the so-called Doi Moi 2.0 characterized by greater proactiveness and determination. Applications of this study: This study has implication for policymakers, scholars and experts in the disciplines and subfields of politics, international relations, foreign policy analysis given that Vietnam has been well known for its significant achievements in its diplomatic relations after the Cold War and it is playing a growing role in regional and international affairs. The originality of this study: This study makes an original contribution to the existing literature of Vietnam’s foreign policy because it digs into an issue where only a few numbers of scholars have touched upon and provides a comprehensive analysis of the factors influencing Hanoi’s mindset, shaping Vietnam’s national interests and formulating Vietnam’s foreign policy in the coming decades

A Study on Derailment at Railway Turnout Using the Multi-body Dynamics Simulation

In this study, the locomotive and the turnout were simulated with three-dimensional models. The purpose of this study is prediction the derailment phenomenon of the locomotive running on the turnout in Vietnam. Multi-body simulations were implemented by SIMPACK software to determine the derailment coefficient, the wheel unloading factor, and the lateral force. The interaction between the locomotive and the track structure at turnout was considered unified. The derailment coefficient, the wheel unloading factor, and the lateral force were calculated for locomotive-D19E at turnout (tg0.15) for 1000 mm gauge according to QCVN 18:2011/BGTVT, EN 14363:2016, and TCVN 8784:2011. The derailment coefficient, the wheel unloading factor, and the lateral force for the locomotive at max speed V=27.8 km/h are 0.94, 0.61, and 67.46 kN, respectively. These results show that the locomotive will not derail when it passes the turnout at a speed V 27.8 km/h

“I can't get it out of my mind” - Why, how, and when crisis rumination leads entrepreneurs to act and pivot during crises

Why do some entrepreneurs pivot their business models in a crisis, while others are more passive? Integrating Conservation of Resources theory with work on crisis rumination, we developed a micro-level model to explain why entrepreneurs who are under strain due to a crisis, as indicated by experiencing crisis rumination, adopt an active approach – i.e., using active coping and engaging in pivoting. Moreover, prevention-focused entrepreneurs who are habitually more sensitive to losses are especially stimulated by crisis rumination to pivot to prevent (further) resource losses. We tested our model in an experiment and an eight-month longitudinal study with entrepreneurs during an inflation crisis