Engineering Commons^™

Asynchronous Phase Rotor Generators For Power Planes Operating Parallel With A Network, Sharafiddin Kamaliddinovich Alimhodzhaev, Odil Umirzakovich Zakhidov, Mirzohid Hurramovich Taniev

Journal of Tashkent Institute of Railway Engineers

The article presents the results of studies of asynchronous generators of wind power plants and small hydroelectric power stations operating in parallel with the electric network. The parameters of the equivalent circuit are specified, on the basis of which the analytical dependence of the electromagnetic moment of the generator is found. It is proposed to take into account the revealed features of the mechanical characteristics of the generators that differ from the characteristics determined by the generally accepted analytical method

Comparative Analysis Of Functional Diagnostic Methods Of Traction Asynchronous Motors, Zhavkharbek Sulton Ugli Fayzullaev

Journal of Tashkent Institute of Railway Engineers

The article provides a comparative analysis of the methods of functional diagnostics of traction induction motors and justifies that of them the most promising are thermal, electric, vibroacoustic and magnetic methods. To obtain the most reliable information in diagnosing the technical condition of traction induction motors, it is recommended that the methods considered be used in conjunction with the simultaneous improvement of their technical means.

The Research Of Transient Processes In Current Transformers By The Operator's Method, Sultan Fayzullayevich Amirov, Shavkat Mukhsimov, Otabek Tashmuhammatovich Boltayev

Journal of Tashkent Institute of Railway Engineers

In the article the transient processes occurring in current transformers are investigated and the values of the magnetization current are determined by the operator method using the primary current source. Using the obtained results, the regularities of the magnetization current change in time are analyzed. For the investigated wide-range current transformer with a closed and open core, that is, at different values of T', a comparative analysis of the laws of change in time of the aperiodic components of the magnetic current was carried out. It is determined that current transformers with air gap are effective in all cases when …

On The Dynamics Of The Movement Carriage In The Accelerating Grable The Marshalling Yard, Shukhrat Umarkhodjaevich Saidivaliev, Zakhro Valijanovna Ergasheva

Journal of Tashkent Institute of Railway Engineers

The article presents the results of studies of the movement of the carriage on the slope hump (including brake position) when exposed to the forces of wind. Maintaining acceptable speed impacts and screening the Park can be achieved by changing the profiles of individual sections of the drain side hump or application of additional wagon retarders.

Evaluation Of Concrete Deck Curing Regimens Using Capillary Pressure Sensing System, Samuel Spann

Graduate Theses and Dissertations

Early-age plastic shrinkage cracking is a common problem with the construction of concrete bridge decks due to the high surface area-to-volume ratio and exposure to potentially detrimental environmental effects. Curing regimens are utilized to mitigate cracking risk during the plastic stage of the concrete; the curing regimens evaluated for this study were wet burlap-polyethylene sheeting, two acrylic curing compounds, and one lithium compound. Capillary pressure in the water filled pores has been shown to correlate to the plastic shrinkage cracking risk of concrete. A new portable system has been developed to measure the capillary pressure that could potentially be used …

Truck Activity Pattern Classification Using Anonymous Mobile Sensor Data, Taslima Akter

Graduate Theses and Dissertations

To construct, operate, and maintain a transportation system that supports the efficient movement of freight, transportation agencies must understand economic drivers of freight flow. This is a challenge since freight movement data available to transportation agencies is typically void of commodity and industry information, factors that tie freight movements to underlying economic conditions. With recent advances in the resolution and availability of big data from Global Positioning Systems (GPS), it may be possible to fill this critical freight data gap. However, there is a need for methodological approaches to enable usage of this data for freight planning and operations.

To …

Study Of Internal Strains Developed In Concrete Decks At Early Ages In Steel Continuous Bridges, Fernando R. Benitez Ortiz

Graduate Theses and Dissertations

The Arkansas Department of Transportation (ARDOT) has identified bridge deck cracking shortly after concrete decks are placed and prior to applying traffic loads. Previous researchers have confirmed improper construction practices and design methods can lead to deck cracking. Currently, many contractors throughout Arkansas are using continuous deck pours. This construction approach may restrict the concrete slab from movement during early age shrinkage, causing tensile stresses to develop. The final stresses at the end of construction must be lower than the concrete tensile strength, if not cracking issues will develop. Eventually, these cracks may enlarge due to service load stresses and …

Weigh-In-Motion Auto-Calibration Using Automatic Vehicle Identification, Fu Ren Zhang Zhang Durandal

Graduate Theses and Dissertations

Weigh-in-Motion (WIM) sensors are installed on mainline lanes at highway locations to record vehicle weights, axle spacing, vehicle class, travel speed, vehicle length, and traffic volume. These data elements support effective transportation planning, infrastructure design, and policy development. Therefore, it is important that WIM sensors supply accurate data. After initial installation and calibration, WIM systems may experience measurement drifts in weight and axle detection. Recalibration takes two general forms: (a) On-site calibration involving running trucks of known weight over WIM scales and (b) Auto-calibration methods involving comparisons to assumed reference weights. Auto-calibration can be more cost and time effective than …

Evaluation Of Fracture Principles In Asphalt Concrete Utilizing The Sc(B) Geometry, Airam Marlee Morales Vega

Graduate Theses and Dissertations

Since cracking is one of the principal distresses to be considered in asphalt concrete, multiple fracture tests and geometries have been used to quantify cracking resistance. One of the most popular geometries that have been used in fracture tests is the Semi-Circular bend (SC(B)). However, for this geometry, most of the fracture test methods use different parameters such as thickness, testing temperatures, and loading rates. Thus, the purpose of this research was first to evaluate fracture energy by performing a ruggedness test based on ASTM E1169. Then, to apply fracture mechanics concepts to evaluate three specimen thicknesses (25, 50, and …

An Application Of Bayesian Multilevel Model To Evaluate Variations In Stochastic And Dynamic Transition Of Traffic Conditions, Emmanuel Kidando, Ren Moses, Thobias Sando, Eren Erman Ozguven

Civil and Environmental Engineering Faculty Publications

© 2019, The Author(s). This study seeks to investigate the variations associated with lane lateral locations and days of the week in the stochastic and dynamic transition of traffic regimes (DTTR). In the proposed analysis, hierarchical regression models fitted using Bayesian frameworks were used to calibrate the transition probabilities that describe the DTTR. Datasets of two sites on a freeway facility located in Jacksonville, Florida, were selected for the analysis. The traffic speed thresholds to define traffic regimes were estimated using the Gaussian mixture model (GMM). The GMM revealed that two and three regimes were adequate mixture components for estimating …

Evaluation Of Reducing Cement Content In Ndor Class R Combined Aggregate Gradations, Miras Mamirov, Jiong Hu, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

The main objective of this research project was to achieve a cement reduction on Nebraska slip-form pavement concrete through aggregate particle packing optimization. A literature review was conducted to examine different aggregate optimization tools, quality control tests, and historical data of Nebraska Department of Transportation (NDOT) pavement mixtures. It was found that the Modified Toufar Model has good potential in optimizing particle packing and predicting packing degrees. The combined aggregate void content test was found to be useful to experimentally justify optimized aggregate gradations. The Box Test with a modified index and image analysis tool for surface void estimation was …

Long-Term Performance Evaluation Of Nudeck In Kearney East Bypass, George Morcous, Marc Maguire

Nebraska Department of Transportation: Research Reports

The Kearney East Bypass bridge is the first project that implements the newly developed precast concrete deck system (known as 2nd generation NUDECK). The new system consists of full-depth full-width precast prestressed concrete deck panels that are 12 ft (3.66 m) long each. The panels have covered shear pockets at 4 ft (1.22 m) spacing on each girder line to host clustered shear connectors that are adjustable in height. Narrow unreinforced transverse joints are used to eliminate the need for deck overlay. Also, deck panels are post-tensioned in the longitudinal direction using a new post-tensioning system that eliminates the need …

Standard Design For Nebraska County Bridges, Chungwook Sim, Jiong Hu, Maher K. Tadros, Alexander Bleyhl, David Gee

Nebraska Department of Transportation: Research Reports

Many county-owned bridges in Nebraska need replacement due to their structural deficiency. Most of the bridges needing replacement are in the 40 to 60 ft range. This span range lacks a standard design that fits Nebraska county practices in terms of speed and simplicity of construction. The current systems being used are (a) Precast 1 by 2 ft planks which can span up to 30 ft, (b) Cast-in-place slab bridges which can span up to 50 ft but require extensive field formwork, concrete placing, and curing, and are best when constructed in three-span units, and (c) Inverted tees which can …

Precast Concrete Deck-To-Girder Connection Using Uhpc, George Morcous, Mostafa Abo El-Khier

Nebraska Department of Transportation: Research Reports

The implementation of ultra-high-performance concrete (UHPC) in bridge construction has been growing rapidly in the last two decades due to its excellent mechanical properties, workability, and durability. This report presents a new UHPC connection between precast concrete deck panels and bridge girders that eliminates changes to the design and production of girder shear connectors commonly used in conventional cast-in-place concrete deck construction. In conventional construction, girder shear reinforcement or studs are extended into the cast-in-place concrete deck to transfer interface shear and create composite section. In the new connection, girder shear reinforcement or studs are kept underneath the deck panels, …

Development Of High-Performance Rapid Patching Materials For Pavement Repair, Gholami Shayan, Jiong Hu, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

Concrete pavements exhibiting severe distresses which require patching are commonly observed in the concrete pavement in Nebraska. Due to the requirements of opening pavement to traffic after placing the rapid patching materials, it is essential for that concrete to achieve high early strength. To ensure this, a high cement content and chloride-based accelerators are currently used in the Nebraska Department of Transportation (NDOT) Portland cement-based rapid-patching materials. Besides its associated high cost, high cement content tends to result in a less stable mix with high shrinkage, high heat of hydration, and high cracking potential. In addition, using chloride-based accelerators has …

Condition Assessment Of Bridge Decks With Asphalt Overlay, Sepehr Pashoutani, Jinying Zhu

Nebraska Department of Transportation: Research Reports

Ground penetrating RADAR (GPR) is a widely used nondestructive testing (NDT) method for bridge deck evaluation. However, the current GPR signal and data processing software and algorithms are not able to provide comprehensive information about bridge deck condition. Although the original objective of this research project was to develop GPR analysis algorithms for condition assessment of bridge decks with asphalt overlay, the scope of work has been expanded to concrete bridge decks with or without overlays.

In this study, the research team developed a complete GPR analysis procedure that includes the following components: 1) obtain zero-time for GPR reflection at …

Building Along The Railroad: Towns And Tourism In Michigan’S Eastern Upper Peninsula, Bridget Stoetzer

Honors Projects

The state of Michigan is not solely the lower portion or in other words the “mitten.” It is a combination of the lower and upper peninsula. The Upper Peninsula of Michigan (abbreviated the “UP”) is the upper portion of Michigan that is surrounded on three sides by three different Great Lakes: Lake Superior, Lake Michigan, and Lake Huron. It connects to the Lower Peninsula of Michigan by the Mackinac Bridge which crosses five miles across the Straits of Mackinac.

The counties of the Eastern Upper Peninsula are Alger, Chippewa, Luce, Mackinac, and Schoolcraft. They are marked by large stretches of …

Fractional Order State Feedback Control For Improved Lateral Stability Of Semi-Autonomous Commercial Heavy Vehicles, Rasheed Mazen Abdulkader

Graduate Theses and Dissertations

With the growing development of autonomous and semi-autonomous large commercial heavy vehicles, the lateral stability control of articulated vehicles have caught the attention of researchers recently. Active vehicle front steering (AFS) can enhance the handling performance and stability of articulated vehicles for an emergency highway maneuver scenario. However, with large vehicles such tractor-trailers, the system becomes more complex to control and there is an increased occurrence of instabilities. This research investigates a new control scheme based on fractional calculus as a technique that ensures lateral stability of articulated large heavy vehicles during evasive highway maneuvering scenarios. The control method is …

Evaluating Urban Downtown One-Way To Two-Way Street Conversion Using Microscopic Traffic Simulation, Bernice Liu

Master's Theses

Located in the heart of Silicon Valley, Downtown San Jose is attracting new residents, visitors, and businesses. Clearly, the mobility of these residents, visitors, and businesses cannot be accommodated by streets that focus on the single-occupancy automobile mode. To increase the potential for individuals to use non-single-occupancy modes of travel, the downtown area must have a cohesive plan to integrate multimodal use and public life. Complete streets are an integral component of the multi-modal transport system and more livable communities. Complete streets refer to roads designed to accommodate multiple modes, users, and activities including walking, cycling, transit, automobile, and nearby …

The Potential For Using Loyalty Rewards And Incentives Programs To Encourage Transit Ridership And Regional Transportation And Land Use Integration, Christopher E. Ferrell

Mineta Transportation Institute

Transit smart cards can be used as a tool for increasing transit ridership, increasing retail sales in transit-oriented developments (TODs) and eventually, increasing opportunities for retail development in TODs. Instead of providing separate loyalty rewards for each store, or chain of stores, such cards would provide loyalty rewards—in several possible forms, including free transit ride credits, cash rewards, retail purchase discounts, sweepstakes rewards—to all transit riders who patronize TOD retail businesses. Additional rewards could also be given to transit riders who live, work, and shop in TODs, and even to riders who take transit for specific shopping trips in TODs. …

The Application Of Gray-Scale Level-Set Method In Segmentation Of Concrete Deck Delamination Using Infrared Images, Chongsheng Cheng, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Conventional nondestructive delamination detection of concrete pavements through thermography is often based on temperature contrasts between delaminated and sound areas. Non-uniform backgrounds caused by the environmental conditions are often challenging for contrast-based methods to robustly differentiate the delaminated areas from the sound areas. Instead of focusing on the temperature contrast, this study proposes a temperature gradient-based level set method (LSM) to detect boundaries for delamination segmentations. A modified edge indicator function is developed to represent the normalized temperature gradient of a thermal image. The experimental study was conducted to evaluate its applicability and stability for boundary detection in terms of …

Evaluation Of The Rheological Behaviors And Molecular Composition Properties Of Crumb Rubber Modified Emulsion For Chip Seal, Md Tanvir Ahmed Sarkar

LSU Master's Theses

An experimental study was conducted to characterize the chemical, molecular, and rheological properties of different asphalt emulsions including a newly introduced tire rubber modified asphalt emulsion. One tire rubber modified asphalt emulsion (CRS-2TR), two conventional emulsions (CRS-2 and CRS-2P), and one asphalt rubber binder (AC20-5TR) were evaluated. The differences in functional groups, chemical composition, and molecular weight distribution of the asphalt binder and emulsions under different aging conditions (Original, RTFO-aged, and PAV-aged) were evaluated by the Saturates, Aromatics, Resins and Asphaltenes (SARA) fractionation test, High-Pressure Gel Permeation Chromatography (HP-GPC), and Fourier Transform Infrared Spectroscopy (FTIR) test, respectively. Superpave Performance Grade …

Application Of Modern, Effective Materials In Rail Road Reinforced Bridge Elements, U.Z. Shermuxamedov, F.Z. Zokirov

Journal of Tashkent Institute of Railway Engineers

The article is about reducing the construction costs of railroad bridges and the effective use modern building materials. The article compares the technical characteristics of composite fittings and metal fittings and their proportionality. Indeed, recourse saving of metal and composite fittings, as well as factors of localization of construction is compared

Mathematical Modeling Of The Structure Cellular Concrete, Anvar Ishanovich Adilkhodjayev, E.V. Shipacheva, S.S. Shaumarov

Journal of Tashkent Institute of Railway Engineers

The article presents the developed mathematical model of the structure of cellular concrete, which allows one to establish pore sizes and characteristics of inter-pore walls corresponding to the required thermal conductivity and strength of the material, and the results of its numerical implementation are presented

Research Of Surface Condition Of The Rails Rollingon Sections Of High-Speed And High-Speed Train Traffic, E.B. Abdualiyev

Journal of Tashkent Institute of Railway Engineers

This article analyzes the intensity of impulse irregularities that occur on the surface of the rolling rail heads on the section of high-speed and high-speed train traffic. On the rolling surface of the rail heads, the formation of pulse irregularities is observed, which are fixed by the measuring system of the track measuring car No. 106. This shows the main character of damage to the surface of the rail head ride

Method Of Calculation Of Self-Stressed Concrete Slabs Supported Along The Contour, S.S. Salixanov

Journal of Tashkent Institute of Railway Engineers

The paper presents the developed method for calculating the contour-supported slab of self-stressed concrete. Reinforced concrete slab on the tension cement replaces the traditional construction of the bridge. In this article, in order to exclude reinforcement, the problem of determining the stress-strain state of self-stressed concrete slabs supported along the contour is considered. The values of stresses in the upper and lower faces of the concrete slab, as well as the bending moment in the middle section of the slab

Construction Features Of Transport Tunnels In The Mountain Areas Of Uzbekistan, M.Х. Miralimov, Sh.U. Normurodov

Journal of Tashkent Institute of Railway Engineers

The paper provides information about the transport tunnel 19,2 km long which was recently completed on new electrified railway line “Angren-Pap” in the mountain area of Uzbekistan. It is noted that the most actual for transport tunnels is account of seismic activity of geological environment in the process of design, construction and maintenance. There are given the effects of earthquakes on underground structures and regularities of displacement and stress distribution in the tunnel linings under seismic impacts. The accumulated experience of earthquake-resistant construction in Uzbekistan shows the need to consider several design schemes for the interaction of tunnels in the …

Research Of System Conditions For Formation Of Failure On Mathematical Models By The Results Of The Research Of Reinforced Concrete Bridges, E.T. Yaxshiev, F.Z. Zokirov, A.B. Karimova

Journal of Tashkent Institute of Railway Engineers

Based on the data of field surveys, the results of assessing the state of reinforced concrete span structures of bridges and characteristic defects that occur in the structure during operation are presented. An analysis of the results of inspections and periodic inspections responsible for the operation of artificial structures shows that a significant part of reinforced concrete spans has various types of defects and damage to load-bearing structures. Studies show that defects have a significant impact on the operational properties of reinforced concrete spans, leading both to a limitation of the speed regime of train movements and to the emergence …

Development Of A Hybrid Model Of A Thermophotogenerator And An Empirical Analysis Of The Dependence Of The Efficiency Of A Photocell On Temperature, S.I. Zokirov, M.N. Sobirov, H.Kh. Tursunov, M.M. Sobirov

Journal of Tashkent Institute of Railway Engineers

This paper presents the results of experiments to analyze the efficiency of the photocell of selective radiation of a photothermogen generator at various densities. It was found that in a relatively hot climate (Uzbekistan, Ferghana), the performance of the solar cell is stable at temperatures from +25 to +35. It was found that the lowest solar cell performance (from single-crystal silicon) was about 6% and 13%, and the highest - about 15% and 16% for typical and selective lighting with triple density in a certain period of time (up to 3 and 15 minutes), respectively. The lux-ampere characteristic is given; …

Diagnostic Method For Current Collectors Of Freight Electric Locomotives In The Conditions Of The Republic Of Uzbekistan, B.B. Abdurakhmanov

Journal of Tashkent Institute of Railway Engineers

The paper provides a method for diagnosing current collectors of freight electric locomotives in the Republic of Uzbekistan in order to increase the reliability of current collectors, as well as reduce the time for their operation. A large number of failures attributable to current collectors, in particular to current collector inserts, were revealed. Improving the reliability, which will improve the reliability of the electric locomotive as a whole. To date, the electric locomotives of the park of the Republic of Uzbekistan do not have the diagnostic tools to determine the condition of current collector inserts. The article provides an algorithm …