Intelligent motion planning and obstacle avoidance for multiple mobile robots in highly cluttered environments

In recent years, the interest in research on robots has increased extensively; mainly due to avoid human to involve in hazardous task, automation of Industries, Defense, Medical and other household applications. Different kinds of robots are used for different applications. In rough terrains, walking robots are usually preferred. On smoother surfaces, wheeled mobile robots have the advantage because of its faster and more alert characteristics. Autonomous navigation in a cluttered and dynamic environment is a huge problem; because it is not possible to create all the possible conditions in the environment. So it is necessary to design the robot control system that can be adapted to different conditions and will be robust in dynamic environments. The robustness of the robot is to reduce the sensor errors and adopt with the sudden changes in environmental condition. The method of robot control may be categorized as deliberative and reactive. Deliberative approach method is used in a completely known environment. In this method the robot control system has feed with the map of the environment, where it has to work. The drawback of this approach is that, it is difficult to create an exact map of the environment and the further modifications in a dynamic environment. In reactive approach no map is required to the control system. The robot has to take decision as per the sensor information. Only the target position is given to the controller of the mobile robot. The sensors collect the data from the environment and navigate accordingly

Rheological characteristics of bauxite slurry with varying concentration, particle size distribution, and modal distribution for pipeline transportation

Some of the foremost parameters effecting the slurry rheology, preferably the slurry concentration, particle size distribution, and modal distributions, were studied in the current findings, figuring out the variation in shear stress and apparent viscosity using a rotational rheometer. The particle size considered for the test ranges from fine particle size of −75 µm to coarse particle size of +75–300 µm, separated at varied size fractions of +75–105, +105–150, +150–210, and +210–300 µm. The −75 µm bauxite slurry at 60 wt% has shown a maximum static settled concentration (Cw-max) under gravity after 48 h free settlement. This fine particle slurry at varying concentrations of Cw = 45–65% is discerned to behave like a Non-Newtonian Bingham plastic fluid at lower concentrations, unlike the other coarse fraction bauxite slurries at Cw =  55%, which exhibit shear thickening behavior. The present work carried out adds knowledge on the rheological behavior of bimodal, trimodal, and multimodal with four and five different size fraction bauxite slurries in finding the optimum mass concentration for a particle size fraction of (coarse):(fine), obtained in the ratio (25):(75), (25:25):(50), (25:25:10):(40), and (15:15:15:15):(40), respectively of the total 60 wt%. Certain parameters, like yield stress, consistency index (k), and flow behavior index (n), were estimated upon fitting the modal distributions to the Herschel Bulkley model to choose the best particle size distribution of the bauxite sample showing improved slurry stability, rheology, and flow characteristics.</p

Behaviour of a Strip Footing on Compacted Pond Ash Reinforced with Coir Geotextiles

Pond ash, produced in huge quantities by thermal power plants, require large land area for disposal and causes environmental hazards. The pond ash can be effectively used as a fill material for low lying areas as site reclamations and in embankments. The low bearing capacity of pond ash fills can be improved by using coir geotextiles, as reinforcement which will be an eco-friendly approach. The effectiveness of horizontally placed coir geotextiles, as reinforcement in single and multiple layers, on the bearing capacity of compacted pond ash is investigated. In the present study, the bearing capacity behaviour of a strip footing on two pond ash samples reinforced with two types of woven coir geotextiles has been studied by load bearing tests in model tanks in the laboratory. The parameters varied during the tests were width of reinforcement, depth of the top reinforcement layer below the base of the footing and the number of geotextile layer. The improvement of ultimate bearing capacity was studied. The ultimate bearing capacity ratios were evaluated. A mathematical model based on the geometric parameters of the reinforcement, tensile properties of reinforcement and shear parameter of pond ash has been developed

An Unusual Cause of Chronic Cough

A 68-year-old male presented with a history of on and off cough for several years which was increased over last month and was associated with low-grade intermittent fever since last four weeks [...

Misdiagnosed Case of Bronchial Carcinoid Presenting with Refractory Dyspnoea and Wheeze: A Rare Case Report and Review of Literature

A 59-year-old male smoker presented with persistent wheezing and occasional coughing that had been ongoing for two years and had been unsuccessfully treated with an inhalational β2 agonist, an anticholinergic and an inhalational steroid in the last year. On clinical examination, a left-sided wheeze was detected. The initial chest X-ray was normal. A computed tomography (CT) scan of thorax demonstrated a mass lesion in the left main bronchus. On subsequent bronchoscopy, an endobronchial polypoid mass was detected in the left main bronchus, completely occluding the bronchial lumen. A biopsy taken from the mass revealed features of bronchial carcinoid. Bronchial carcinoid can present uncommonly with wheezes, resulting in misdiagnosis as bronchial asthma or chronic obstructive pulmonary disease (COPD). If an asthma or COPD patient does not respond to conventional therapy, a CT scan and subsequent bronchoscopy is warranted