Effects of Surface Topographies on Heat and Fluid Flows

Responses of annular and planar flows to the introduction of grooves on the bounding surfaces have been analyzed. The required spectral algorithms based on the Fourier and Chebyshev expansions have been developed. The difficulties associated with the irregularities of the physical domain have been overcome using either the immersed boundary conditions (IBC) concept or the domain transformation method (DT). Steady flows in annuli bounded by walls with longitudinal grooves have been studied. Analysis of pressure losses showed that the groove-induced changes can be represented as a superposition of a pressure drop due to a change in the average position of the bounding cylinders and a pressure drop due to the flow modulations induced by the shape of the grooves. The former effect can be evaluated analytically while the latter requires explicit computations. It has been shown that the reduced-order model is an effective tool for extraction of features of the groove geometry that lead to flow modulations relevant to drag generation. It has been shown that the presence of the longitudinal grooves may lead to a reduction of the pressure loss in spite of an increase of the wetted surface area. The form of the optimal grooves from the point of view of the maximization of the drag reduction has been determined. When mixing augmentation is not available, heat can be transported across micro-channels by conduction only. A method to increase this heat flow has been proposed. The method relies on the use of grooves parallel to the flow direction. It has been shown that it is possible to find grooves that can increase the heat flow and, at the same time, can decrease the pressure losses. The optimal groove shape that maximizes the overall system performance has been determined. Since it has been assumed that the flow must be laminar, it is of interest to determine the maximum Reynolds number for which this assumption remains valid. The stability characteristics of flow in a grooved channel have been studied. Only disturbances corresponding to the travelling waves in the limit of zero groove amplitude have been found. It has been shown that disturbances corresponding to the two-dimensional waves in a smooth channel play the critical role in the grooved channel. The highly three-dimensional disturbance flow topology at the onset of the instability has been described. It has been demonstrated that the presence of the grooves leads to flow stabilization for the groove wave numbers 4.22 and flow destabilization for larger . The stabilizing/destabilizing effects increase with the groove amplitude. Variations of the critical Reynolds number over the whole range of the groove wave numbers and the groove amplitudes of interest have been determined. Special attention has been paid to the effects of the long wavelength, drag reducing grooves. It has been shown that such grooves lead to a small increase of the critical Reynolds number compared with the smooth channel

Modular Customizable ROS-Based Framework for Rapid Development of Social Robots

Developing socially competent robots requires tight integration of robotics, computer vision, speech processing, and web technologies. We present the Socially-interactive Robot Software platform (SROS), an open-source framework addressing this need through a modular layered architecture. SROS bridges the Robot Operating System (ROS) layer for mobility with web and Android interface layers using standard messaging and APIs. Specialized perceptual and interactive skills are implemented as ROS services for reusable deployment on any robot. This facilitates rapid prototyping of collaborative behaviors that synchronize perception with physical actuation. We experimentally validated core SROS technologies including computer vision, speech processing, and GPT2 autocomplete speech implemented as plug-and-play ROS services. Modularity is demonstrated through the successful integration of an additional ROS package, without changes to hardware or software platforms. The capabilities enabled confirm SROS's effectiveness in developing socially interactive robots through synchronized cross-domain interaction. Through demonstrations showing synchronized multimodal behaviors on an example platform, we illustrate how the SROS architectural approach addresses shortcomings of previous work by lowering barriers for researchers to advance the state-of-the-art in adaptive, collaborative customizable human-robot systems through novel applications integrating perceptual and social abilities

"Shami" A Public Life Narrator

The public life of people in most cases are among forgotten parts of the Persian literature; in other words, most of the poets because of their too much attention to the kings and their actions and behaviors, followed by their disconnection with the inferior class of the society, have rarely composed poems on the public life of the people. The constitutional revolution to a great extent shifted this balance in favor of the public. In this paper, the anthology of the Kurdish blind poet “Shami” - which deals with the poor class of the society and the issues relating to it from a linguistic and thematic perspective - has been investigated and on the basis of the issues that embody most in the anthology, the poems relating to the public life have been categorized into four groups: 1. Life appliances and equipment, 2.Number of people, 3. Speech and 4. Customs and etiquette. This investigation showed that Shami is a poet that understands the pains and woes of the people and tries through an eloquent language to express pains and sufferings of his own class in a poetic form, offering it to the public. Hence, he can be called a social poet as suc

A web-based gamification of upper extremity robotic rehabilitation

In recent years, gamification has become very popular for rehabilitating different cognitive and motor problems. It has been shown that rehabilitation is effective when it starts early enough and it is intensive and repetitive. However, the success of rehabilitation depends also on the motivation and perseverance of patients during treatment. Adding serious games to the rehabilitation procedure will help the patients to overcome the monotonicity of the treatment procedure. On the other hand, if a variety of games can be used with a robotic rehabilitation system, it will help to define tasks with different levels of difficulty with greater variety. In this paper we introduce a procedure for connecting a rehabilitation robot to several web-based games. In other words, an interface is designed that connects the robot to a computer through a USB port. To validate the usefulness of the proposed approach, a researcher designed survey was used to get feedback from several users. The results demonstrate that having several games besides rehabilitation makes the procedure of rehabilitation entertaining.Comment: 2021 International Serious Games Symposium (ISGS

Optimization of Cutting Parameters for Pocket Milling on the Skin Plate in Al and Al-Li Materials

RÉSUMÉ L'objectif de cette étude est d'optimiser des paramètres de coupes pour l’usinage de poche sur une plaque mince en alliage d’aluminium et en alliage d’aluminium-lithium. Ces plaques minces sont utilisées dans l’industrie aéronautique pour fabriquer le fuselage d’un avion. Présentement, ces poches sur les plaques minces sont fabriquées par usinage chimique. Cette méthode chimique est dite nocive pour l’environnement. La méthode chimique pourrait être remplacée par une méthode mécanique comme l’usinage. En plus, les paramètres de coupes seront optimisés pour l’alliage d’aluminium-lithium. L’effet des paramètres de coupes a été étudié par des expériences utilisant la méthode de Taguchi. L’analyse de rapport signal sur bruit (Signal to Noise ratio) a été menée sur les données recueillies pour illustrer la significativité des facteurs des plans d’expériences et de leur contribution. La rugosité de la surface sur les pièces a été aussi étudiée et des paramètres optimaux ont été définis. Des vérifications ont été accomplies et la poche sur la plaque a été usinée à la satisfaction des exigences de l'ingénierie de l'industrie.----------ABSTRACT In the present work the pocket machining (milling) of the thin skin components made of aluminium and aluminium-lithium (Al-Li) alloys is studied. These milled components are known as principle parts of commercial airplanes. They have significant impacts on the airplane body weight and fuel consumption. Chemical milling is the main method used for pockets machining on these components. However, this method is not considered as an environmentally friendly operation due to severe contamination problems. To remedy these difficulties, this study intends to replace the chemical milling by an alternative machining method capable to do pocket machining. To that end, pocket milling was selected as machining method. Furthermore, in order to reduce the weight of airplane, an alternative material such as Al-Li alloys is proposed to replace the aluminum alloys. In the first phase of this study, a comprehensive literature review was conducted on milling and pocket milling of aluminum and aluminum-lithium alloys. The sample parts required for cutting operations were prepared in accordance with in specified dimensional geometries of the real parts used in industry. A milling fixture was then designed and manufactured in order to perform machining operations on the sample parts. The experimental tests were planned according to the Taguchi method design of experiment. The cutting parameters studied included: RPM, chip thickness (feed rate), depth of cut and lubricant. The one way and profile contouring milling operations were selected as machining strategies. A process failure mode and effect analysis (FMEA) was executed to determine the main failure modes during pocket milling operations and the surface roughness was used as performance criteria. The experimental results were analyzed using Signal to Noise ratio (S/N) strategy though Taguchi method. According to the experimental results, the optimal setting levels of cutting parameters are RPM (10000 rev/min), chip thickness (0.0508 mm), depth of cut (0.45 mm) and lubricant (MQL, 40 ml/min). Finally, the experimental verification tests were performed. According to the literature, a similar machining specification can be applied for conventional aluminium alloys and the Al-Li alloys. Consequently, in order to reduce the experimental cost and time, the optimum setting levels of process parameters proposed in this work could be applied in the machining of Al-Li work pieces

Automatic Speech Recognition for Speech Assessment of Persian Preschool Children

Preschool evaluation is crucial because it gives teachers and parents influential knowledge about children's growth and development. The COVID-19 pandemic has highlighted the necessity of online assessment for preschool children. One of the areas that should be tested is their ability to speak. Employing an Automatic Speech Recognition(ASR) system is useless since they are pre-trained on voices that are different from children's voices in terms of frequency and amplitude. We constructed an ASR for our cognitive test system to solve this issue using the Wav2Vec 2.0 model with a new pre-training objective called Random Frequency Pitch(RFP). In addition, we used our new dataset to fine-tune our model for Meaningless Words(MW) and Rapid Automatic Naming(RAN) tests. Our new approach reaches a Word Error Rate(WER) of 6.45 on the Persian section of the CommonVoice dataset. Furthermore, our novel methodology produces positive outcomes in zero- and few-shot scenarios.Comment: 8 pages, 5 figures, 4 tables, 1 algorith

Biointegrated and wirelessly powered implantable brain devices: a review

Implantable neural interfacing devices have added significantly to neural engineering by introducing the low-frequency oscillations of small populations of neurons known as local field potential as well as high-frequency action potentials of individual neurons. Regardless of the astounding progression as of late, conventional neural modulating system is still incapable to achieve the desired chronic in vivo implantation. The real constraint emerges from mechanical and physical diffierences between implants and brain tissue that initiates an inflammatory reaction and glial scar formation that reduces the recording and stimulation quality. Furthermore, traditional strategies consisting of rigid and tethered neural devices cause substantial tissue damage and impede the natural behaviour of an animal, thus hindering chronic in vivo measurements. Therefore, enabling fully implantable neural devices, requires biocompatibility, wireless power/data capability, biointegration using thin and flexible electronics, and chronic recording properties. This paper reviews biocompatibility and design approaches for developing biointegrated and wirelessly powered implantable neural devices in animals aimed at long-term neural interfacing and outlines current challenges toward developing the next generation of implantable neural devices