Annular nozzle engine technology

The topics covered include: (1) driver rocket subsystem; (2) annular nozzle engine technology; (3) expansion-deflection nozzle; (4) aerospike-nozzled engine background; (5) aerospike testing; (6) linear aerospike; and (7) the combined cycle engine

Multimodal barometric and inertial measurement unit based tactile sensor for robot control

In this article, we present a low-cost multimodal tactile sensor capable of providing accelerometer, gyroscope, and pressure data using a seven-axis chip as a sensing element. This approach reduces the complexity of the tactile sensor design and collection of multimodal data. The tactile device is composed of a top layer (a printed circuit board (PCB) and a sensing element), a middle layer (soft rubber material), and a bottom layer (plastic base) forming a sandwich structure. This approach allows the measurement of multimodal data when force is applied to different parts of the top layer of the sensor. The multimodal tactile sensor is validated with analyses and experiments in both offline and real-time. First, the spatial impulse response and sensitivity of the sensor are analyzed with accelerometer, gyroscope, and pressure data systematically collected from the sensor. Second, the estimation of contact location from a range of sensor positions and force values is evaluated using accelerometer and gyroscope data together with a convolutional neural network (CNN) method. Third, the estimation of contact location is used to control the position of a robot arm. The results show that the proposed multimodal tactile sensor has the potential for robotic applications, such as tactile perception for robot control, human-robot interaction, and object exploration.</p

How universities have responded to E-learning as a result of Covid-19 challenges

E-learning environments designed with adaptive technology in mind can help students learn and retain information more effectively by enhancing their learning experience and increasing their level of engagement. Here, students' learning styles are considered in creating an adaptable online environment, and the effects on student engagement are examined. For the sake of this study, we've also attempted to describe and compare the suggested adaptive learning environment to an existing e-learning technique. With Covid-19 in the classroom, technology advancements have grown exponentially, and this progress has coincided with the process of teaching and learning. Virtual classrooms necessitated an e-learning process since it was the most user-friendly teaching method. A descriptive, correlative, transversal and prescriptive research approach was used. An online survey was used to gather data to get a random and voluntary sample of 3560 university students from Peru. A lack of reading comprehension is an issue, but students may use communication technologies and the Internet to improve their teaching and to learn via self-learning

Wearable fingertip with touch, sliding and vibration feedback for immersive virtual reality

Wearable haptic technology plays a key role to enhance the feeling of immersion in virtual reality, telepresence, telehealth and entertainment systems. This work presents a wearable fingertip capable of providing touch, sliding and vibration feedback while the user interacts with virtual objects. This multimodal feedback is applied to the human fingertip using an array of servo motors, a coin vibration motor and 3D printed components. The wearable fingertip uses a 3D printed cylinder that moves up and down to provide touch feedback, and rotates in left and right directions to deliver sliding feedback. The direction of movement and speed of rotation of the cylinder are controlled by the exploration movements performed by the user hand and finger. Vibration feedback is generated using a coin vibration motor with the frequency controlled by the type of virtual material explored by the user. The Leap Motion module is employed to track the human hand and fingers to control the feedback delivered by the wearable device. This work is validated with experiments for exploration of virtual objects in Unity. The experiments show that this wearable haptic device offers an alternative platform with the potential of enhancing the feeling and experience of immersion in virtual reality environments, exploration of objects and telerobotics.</p

Time course of oxidative damage in different brain regions following transient cerebral ischemia in gerbils

The time course of oxidative damage in different brain regions was investigated in the gerbil model of transient cerebral ischemia. Animals were subjected to both common carotid arteries occlusion for 5 min. After the end of ischemia and at different reperfusion times (2, 6, 12, 24, 48, 72, 96 h and 7 days), markers of lipid peroxidation, reduced and oxidized glutathione levels, glutathione peroxidase, glutathione reductase, manganese-dependent superoxide dismutase (MnSOD) and copper/zinc containing SOD (Cu/ZnSOD) activities were measured in hippocampus, cortex and striatum. Oxidative damage in hippocampus was maximal at late stages after ischemia (48-96 h) coincident with a significant impairment in glutathione homeostasis. MnSOD increased in hippocampus at 24, 48 and 72 h after ischemia, coincident with the marked reduction in the activity of glutathione-related enzymes. The late disturbance in oxidant-antioxidant balance corresponds with the time course of delayed neuronal loss in the hippocampal CA1 sector. Cerebral cortex showed early changes in oxidative damage with no significant impairment in antioxidant capacity. Striatal lipid peroxidation significantly increased as early as 2 h after ischemia and persisted until 48 h with respect to the sham-operated group. These results contribute significant information on the timing and factors that influence free radical formation following ischemic brain injury, an essential step in determining effective antioxidant intervention