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Growth processes in many living organisms create thin, soft materials with an intrinsically hyperbolic geometry. These objects support novel types of mesoscopic defects - discontinuity lines for the second derivative and branch points - terminating defects for these line discontinuities. These higher-order defects move "easily", and thus confer a great degree of flexibility to thin hyperbolic elastic sheets. We develop a general, higher-order, continuum mechanical framework from which we can derive the dynamics of higher order defects in a thermodynamically consistent manner. We illustrate our framework by obtaining the explicit equations for the dynamics of branch points in an elastic body.

Galaxies are built by complex physical processes with significant inherent stochasticity. It is therefore surprising that the inferred dark matter distributions in galaxies are strongly correlated with the observed baryon distributions leading to various `Baryon-Halo conspiracies'. The fact that no dark matter candidate has been definitively identified invites a search for alternative explanations for such correlations and we present an approach motivated by the behaviors of self organized patterns. We propose a nonlocal relativistic Lagrangian theory for a `pattern field' which acts as an `effective dark matter', built on the idea that defects in this pattern field couple to the baryonic matter distribution. Our theory accounts for the gross structure of cold disk galaxies. We compute galactic rotation curves and derive various galaxy scaling relations including Renzo's rule, the radial acceleration relation, and the existence of the Freeman limit for central surface brightness., 8 pages, 4 figures

Developments in the area of intelligent transportation system in India are constrained due to the difficulty in accurate automated data collection. Many existing automated sensors may not be accurate under Indian traffic conditions due to their heterogeneity and less lane discipline, resulting in erroneous data. Thus, there is a need to develop tools and estimation schemes that can address these errors and still be able to generate reasonably accurate results. The present study addresses this issue, considering the real-time estimation of speed and density. A dynamical systems approach using the Kalman filtering technique was developed. The implementation was done using data fusion where location-based and spatial traffic variables were used. The estimated values were compared with field data and it was observed that the proposed method was reasonably accurate in the presence of erroneous data.

An important aspect from the perspective of operational safety of heavy road vehicles is the detection and avoidance of collisions, particularly at high speeds. The development of a collision avoidance system is the overall focus of the research presented in this paper. The collision avoidance algorithm was developed using a sliding mode controller (SMC) and compared to one developed using linear full state feedback in terms of performance and controller effort. Important dynamic characteristics such as load transfer during braking, tyre-road interaction, dynamic brake force distribution and pneumatic brake system response were considered. The effect of aerodynamic drag on the controller performance was also studied. The developed control algorithms have been implemented on a Hardware-in-Loop experimental set-up equipped with the vehicle dynamic simulation software, IPG/TruckMaker®. The evaluation has been performed for realistic traffic scenarios with different loading and road conditions. The Ha...

It has been observed during the operation of the diesel engine fuel injection pump that the fuel and the lubrication oil leak through the working clearance between the piston and the cylinder bore and mix with each other. The leakage of lubrication oil to fuel (OtF) leads to injector nozzle coking and emission, which necessitates the automotive industry to design a robust fuel injection pump to meet stringent emission norms. Similarly, the leakage of fuel to lubrication oil leads to depreciation of lubrication property of the oil, thereby reducing the life of engine oil lubricated components. In this research, the leakage flow through this clearance gap was studied using the numerical simulation tool, Ansys CFX, to estimate the volume flow rate of lubrication oil to fuel and fuel to lubrication oil. Pressure and drag effects are two important mechanisms that drive the leakage process. The simulation was carried out for various design parameters such as clearance, clearance taper and speed, and experiments were performed to determine the lubrication oil to fuel and fuel to lubrication oil flow rates. The diluted samples collected from fuel and lubrication oil tanks were analyzed using ICP-AES (inductively coupled plasma – atomic emission spectrometry) for calcium and barium element tracing. Calibration was performed on the ICP bench to study the accuracy and repeatability of the test sample analysis method. The results of numerical simulations and experiments were compared for various design parameters. The proposed analysis could serve as a valuable aid in the fuel injection pump development process.

We introduce a model for the dynamics of oil in suspension, appropriate for shallow waters, including the nearshore environment. This model is capable of oil mass conservation and does so by evolving the oil on the sea surface as well as the oil in the subsurface. The shallower portion of the continental shelf poses compounding unique modeling challenges. Many of these relate to the complex nature of advection and dispersion of oil in an environment in which wind, waves, as well as currents all play a role, as does the complex bathymetry and the nearshore geography. In this study we present an overview of the model as well as derive the most fundamental of processes, namely, the shallow water advectiion and dispersion processes. With regard to this basic transport, we superate several fundamental challenges associated with creating a transport model for oil and other buoyant pollutants, capable of capturing the dynamics at the large spatio-temporal scales demanded by environmental and hazard mitigation studies. Some of the strategies are related to dimension reduction and upscaling, and leave discussion of these to companion papers. Here we focus on wave-filtering, ensemble and depth-averaging. Integral to the model is the proposal of an ocean dynamics model that is consistent with the transport. This ocean dynamics model is detailed here. The ocean/oil transport model is applied to a couple of physically-inspired oil-spill problems in demonstrate its specialized capabilities.

The CRISPR/Cas9 system is an efficient genome editing method that can be used in functional genomics research. The fall armyworm, Spodoptera frugiperda, is a serious agricultural pest that has spread over most of the world. However, very little information is available on functional genomics for this insect. We performed CRISPR/Cas9-mediated site-specific mutagenesis of three target genes: two marker genes [Biogenesis of lysosome-related organelles complex 1 subunit 2 (BLOS2) and tryptophan 2, 3-dioxygenase (TO)], and a developmental gene, E93 (a key ecdysone-induced transcription factor that promotes adult development). The knockouts (KO) of BLOS2, TO and E93 induced translucent mosaic integument, olive eye color, and larval-pupal intermediate phenotypes, respectively. Sequencing RNA isolated from wild-type and E93 KO insects showed that E93 promotes adult development by influencing the expression of the genes coding for transcription factor, Kruppel homolog 1, the pupal specifier, Broad-Complex, serine proteases, and heat shock proteins. Often, gene-edited insects display mosaicism in which only a fraction of the cells are edited as intended, and establishing a homozygous line is both costly and time-consuming. To overcome these limitations, a method to completely KO the target gene in S. frugiperda by injecting the Cas9 protein and multiple sgRNAs targeting one exon of the E93 gene into embryos was developed. Ten percent of the G0 larvae exhibited larval-pupal intermediates. The mutations were confirmed by T7E1 assay, and the mutation frequency was determined as >80%. Complete KO of the E93 gene was achieved in one generation using the multiple sgRNA method, demonstrating a powerful approach to improve genome editing in lepidopteran and other non-model insects.

In this essay we explore analogies between macroscopic patterns, which result from a sequence of phase transitions/instabilities starting from a homogeneous state, and similar phenomena in cosmology, where a sequence of phase transitions in the early universe is believed to have separated the fundamental forces from each other, and also shaped the structure and distribution of matter in the universe. We discuss three distinct aspects of this analogy: (i) Defects and topological charges in macroscopic patterns are analogous to spins and charges of quarks and leptons; (ii) Generic (3+1) stripe patterns carry an (energy) density that accounts for phenomena that are currently attributed to dark matter; (iii) Space-time patterns of interacting nonlinear waves display behaviors reminiscent of quantum phenomena including inflation, entanglement and dark energy., 15 Pages, Essay with 3 technical appendices

This work proposes a method to simulate wheel lock of a Heavy Commercial Road Vehicle (HCRV) using pneumatic brake circuit on a brake dynamometer. The proposed methodology lumps the effects of wheel slip and load transfer during straight-line braking into ‘equivalent inertia’ on the wheels. This inertia profile could then be imported on a dynamometer interface and realized using suitable inertia discs and an electric motor. Equivalent inertia was computed from test datasets obtained from a Hardware-in-Loop (HiL) experimental system consisting of an air brake system and IPG TruckMaker®, a vehicle dynamic simulation software. These datasets were obtained for various road, vehicle load and braking conditions. This framework would facilitate the evaluation of wheel slip regulation algorithms using a brake dynamometer by capturing necessary dynamics of HCRVs during braking. It is expected that such testing can be placed between HiL and on-road tests, and would provide greater confidence in Active Safety Systems (ASSs) before their deployment on vehicles.

This paper deals with tracking of desired yaw rate generated by the path planner of an Autonomous Ground Vehicle (AGV) in the presence of unmodeled dynamics, changes in operating conditions and parametric uncertainties. A mathematical model considering the dynamics of the test vehicle and the steering actuator was used for controller design. The estimate of the unknown part of dynamics, called the total disturbance, obtained from the Extended State Observer (ESO) was used by Sliding Mode Controller (SMC) to compensate the actual total disturbance. It was observed that the lower bound on the SMC switching gain depends on the ratio of total disturbance estimation error and assumed known part of the system dynamics. This allows the choice of a low value of SMC switching gain, which in turn resulted in reduced chattering amplitude. Further attenuation in chattering was achieved using a saturation function. After simulating the designed controller in MATLAB-SIMULINK environment, the controller was validated in IPG: CarMaker® simulation platform over a large operating range by changing the mass distribution of the vehicle, speed of the vehicle, cornering stiffness of the tire and terrain friction coefficient. A look-up table was formulated for the maximum achievable yaw rate at different speeds, i.e., from 5 to 20 m/s, given the maximum steering angle input considering rollover and slip threshold while the terrain friction coefficient was also varied from 0.2 to 0.8. It was observed that the designed controller was robust to changes in operating conditions, parametric uncertainties and unmodeled dynamics.

The phenomenon of platoon dispersion deals with the spreading out of groups of vehicles discharged together from a signal (platoon) as they move along the roadway during normal traffic oper...

While the influence of pavement roughness on the dynamic load transferred is recognized in pavement engineering, the actual implementation of the same for routine pavement stress analysis or for distress computation is fraught with difficulties due to the substantial computational effort involved. In this regard, it would be beneficial to develop load safety factors for different degrees of roughness of pavement by taking into account the extent of dynamic loading experienced by the pavement due to its roughness. For this purpose, the dynamic load transferred to the pavement was determined for different degrees of roughness by conducting simulations using the commercial software TruckMaker. Following the guidelines of ISO 8608, five different road profiles having different levels of roughness were generated. Using the Truck Maker software, the dynamic load transferred to the pavement for these five road profiles were simulated for two different trucks with different wheelbase but identical net weight. The 95th percentile of the obtained dynamic load was used to develop load safety factors as a function of the grade of the pavement.

Active safety is of utmost importance in heavy road vehicles due to the relatively higher number of fatalities encountered in their accidents. Vehicle-to-Vehicle (V2V) technology, which is seen as a future of connected vehicles, can potentially complement onboard sensing to reduce the time taken for detection, and to plan the path with the information available from road side units (RSU). This paper investigates the effect of Iatency in (V2V) communication on a collision avoidance algorithm developed for heavy road vehicles. Experiments performed on a Hardware-in-Loop (HiL) setup were used to evaluate the effect of Iatency for various scenarios. It was found that Iatency had a counterbalancing effect on vehicle spacing and relative longitudinal speed that led to insignificant changes in the final spacing. Further, a sensitivity analysis done at different host vehicle longitudinal speeds demonstrated the need of a variable time headway.

In recent years, the problem of bus travel time prediction is becoming more important for applications such as informing passengers regarding the expected bus arrival time in order to make public transit more attractive to the urban commuters. One of the popular techniques reported for such prediction is the use of time series analysis. Most of the studies on the application of time series techniques for bus arrival time prediction used Box-Jenkins AutoRegressive Integrated Moving Average (ARIMA) models, which are presently not suited for real time implementation. This is mainly due to the necessity and dependence of ARIMA models on a time series modelling software to execute. Moreover, the ARIMA model building process is time consuming, making it difficult to use for real-time implementations. Alternatively, Exponential Smoothing (ES) methods can be used, as they are easy to understand and implement when compared to ARIMA models. The present study is an attempt in this direction, where the basic equation of ES is used, as the state equation with Kalman filtering to recursively update the travel time estimate as the new observation becomes available. The proposed algorithm of state space formulation of ES with Kalman filtering for bus travel time and arrival time prediction was field tested using 105 actual bus trips data along a particular bus route from Chennai, India. The results are promising and a comparison of the proposed algorithm with ES alone without state space formulation and Kalman filtering has also been performed. An information system based on a webpage for real-time display of bus arrival times has been designed and developed using the proposed algorithm. First published online:12 Oct 2015

With increasing numbers of road vehicles and accident fatalities, it is imperative to equip vehicles with active safety systems that can assist drivers. The commonly used actuator in any such active safety system is the vehicle brake system and hence its accurate control becomes important. This paper presents a systematic procedure for modeling the pneumatic brake system in heavy road vehicles using a Linear Time Invariant (LTI) approximation and controlling it based on the developed model. The proposed modeling approach is based on frequency response in the system's frequency range of interest and time response of the system. The model thus obtained was then used to systematically design controllers for brake pressure regulation. The good correlation of theoretical and experimental results corroborated the overall procedure followed for modeling and controller design. Such a controller would serve as an inner loop controller in vehicle control systems like wheel slip regulation, thus improving the brake system performance and vehicle stability.

In this paper, a dynamic mathematical model of an autonomous ground vehicle was used to analyse its transient response and to design a heading-angle controller for the vehicle. A suitable ‘control-oriented model’ that could accurately characterize the phenomenon of interest was used to design the controller. The efficacy of this model was evaluated by corroborating its results with experimental data. This model included the cornering stiffness of the tyres as an unknown parameter, and two approaches were attempted to estimate its value. The dynamics of the actuator were included in the analysis since the response time to steer the front wheel is of the same order as that of the heading-angle dynamics of the vehicle. The performance of two controllers (namely a classical transfer-function-based controller and an optimal linear quadratic regulator) were evaluated using the IPG: CarMaker® simulation platform over a range of speeds. The transfer-function-based controller was also implemented on the experimental test vehicle at low speeds (high-speed experimental implementation was not possible because of safety concerns). It was found that control gain scheduling helped to track the desired heading angles of the vehicle at various speeds. Subsequently, a lane-change manoeuvre using the test vehicle was performed to evaluate the controller further. It was found that the transfer-function-based heading-angle controller could provide a comparable performance with that of the linear quadratic regulator, while keeping the sensing requirements to a minimum; thus, it was suitable for real-time implementation in an autonomous ground vehicle.

In this paper, a rear-wheel-driven series hybrid electric vehicle which has a mechanically operated friction brake system is studied. A new cooperative control of regenerative braking and friction braking called ‘combined braking’ is proposed for this vehicle configuration. A mechanism to adjust the proportions of regenerative braking and friction braking was proposed in this paper. Further, the braking force distribution between the front wheels and the rear wheels was analysed to ensure stable braking. The brake system characteristics were considered to ensure that the driver’s feel remains the same in the new proposed combined braking strategy. The simulation results under urban driving and across the Modified Indian Driving Cycle and vehicle road testing results show that the proposed combined braking can regenerate more than twice the braking energy of conventional parallel braking. Also, with combined braking, the braking force distribution between the front wheels and the rear wheels is closer to the ideal braking force distribution curve, which is desirable to ensure stable braking.

This paper describes the design and implementation of a controller to track the desired heading angle for an unmanned ground vehicle (UGV) considering the limits on rotation of steering wheel and steering motor rate. The well-known �bicycle model� approximation, that considers the vehicle slip angle and ground-wheel interaction, has been used. In this work, combined closed loop control for steering motor and heading angle of the vehicle has been considered for better accuracy. The challenge in designing this control system is to include the actuator dynamics as the response time to steer the front wheel is in the same order as that of the heading angle dynamics of the vehicle. Experiments have been conducted, analysis of data collected is presented and the resulting mathematical representation is explained in detail. Results from both simulation and experimental implementation are also compared. It has been found that the vehicle controller can be tuned effectively to achieve the desired heading angle changes up to twenty degrees within three seconds when the vehicle is moving at a speed of 1.4 m/sec. � 2015, The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.

Even though new infrastructure is being developed to meet demand, increased urbanization and vehicle ownership have increased the congestion levels in Indian cities. Attracting more travelers to public transport is an option to reduce congestion but still remains a challenge, mainly because of the uncertainty of service. A reliable and accurate system for predicting vehicle arrival can help make public transportation more attractive. An accurate prediction method should be used to provide reliable information to passengers, and accuracy depends on the input data used. Therefore, identifying the optimum inputs and incorporating them in the prediction method become important. The optimum number of inputs required for best prediction performance was identified with an analytical approach. A model-based algorithm motivated by the Kalman filter was used to predict bus travel time with the use of GPS data. A case study was conducted on two selected bus routes in the city of Chennai, India, to evaluate the prediction accuracy of the proposed method. Results obtained from the algorithm were promising and showed the prediction accuracy to be 65 min for a prediction window of 30 min in 92% of instances. The predicted travel time can be used to provide realtime bus arrival information to the public through various media, including web pages, mobile applications, and display boards.