Nido-Hydroborate-Based Electrolytes for All-Solid-State Lithium Batteries

Hydroborate-based solid electrolytes have recently been successfully employed in high voltage, room temperature all-solid-state sodium batteries. The transfer to analogous lithium systems has failed up to now due to the lower conductivity of the corresponding lithium compounds and their high cost. Here LiB₁₁H₁₄ nido-hydroborate as a cost-effective building block and its high-purity synthesis is introduced. The crystal structures of anhydrous LiB₁₁H₁₄ as well as of LiB₁₁H₁₄-based mixed-anion solid electrolytes are solved and high ionic conductivities of 1.1 × 10⁻⁴ S cm⁻¹ for Li₂(B₁₁H₁₄)(CB₁₁H₁₂) and 1.1 × 10⁻³ S cm⁻¹ for Li₃(B₁₁H₁₄)(CB₉H₁₀)₂ are obtained, respectively. LiB₁₁H₁₄ exhibits an oxidative stability limit of 2.6 V versus Li⁺/Li and the proposed decomposition products are discussed based on density functional theory calculations. Strategies are discussed to improve the stability of these compounds by modifying the chemical structure of the nido-hydroborate cage. Galvanostatic cycling in symmetric cells with two lithium metal electrodes shows a small overpotential increase from 22.5 to 30 mV after 620 h (up to 0.5 mAh cm⁻²), demonstrating that the electrolyte is compatible with metallic anodes. Finally, the Li₂(B₁₁H₁₄)(CB₁₁H₁₂)  electrolyte is employed in a proof-of-concept half cell with a TiS₂ cathode with a capacity retention of 82% after 150 cycles at C/5.     

Solidification and Re-melting Phenomena During Slurry Preparation Using the RheoMetal™ Process

The melting sequence of the enthalpy exchange material (EEM) and formation of a slurry in the RheoMetal? process was investigated. The EEM was extracted and quenched, together with a portion of the slurry at different processing times before complete melting. The EEM initially increased in size/diameter due to melt freezing onto its surface, forming a freeze-on layer. The initial growth of this layer was followed by a period of a constant diameter of the EEM with subsequent melting and decrease of diameter. Microstructural characterization of the size and morphology of different phases in the EEM and in the freeze-on layer was made. Dendritic equiaxed grains and eutectic regions containing Si particles and Cu-bearing particles and Fe-rich particles were observed in the as-cast EEM. The freeze-on layer consisted of dendritic aluminum tilted by about 30 deg in the upstream direction, caused by the rotation of the EEM. Energy dispersion spectroscopy analysis showed that the freeze-on layer had a composition corresponding to an alloy with higher melting point than the EEM and thus shielding the EEM from the surrounding melt. Microstructural changes in the EEM showed that temperature rapidly increased to 768 K (495 °C), indicated by incipient melting of the lowest temperature melting eutectic in triple junction grain boundary regions with Al₂Cu and Al₅Mg₈Si₆Cu₂ phases present. As the EEM temperature increased further the binary Al-Si eutectic started to melt to form a region of a fully developed coherent mushy state. Experimental results and a thermal model indicated that as the dendrites spheroidized near to the interface at the EEM/freeze-on layer reached a mushy state with 25 pct solid fraction, coherency was lost and disintegration of the freeze-on layer took place. Subsequently, in the absence of the shielding effect from the freeze-on Layer, the EEM continued to disintegrate with a coherency limit of a solid fraction estimated to be 50 pct.     

Reasoning about nature of contact for planning manipulators tasks

Extracting information about contact between two convex bodies from the measured force vector is a prerequisite for any fine compliant motion control strategy. Contact information contains the direction and orientation of the contact surface normal and its relative location and orientation with respect to the compliant reference frame system.A method for interpreting the contact force feedback during compliant robot motion control, using kinematic screws, is presented. Domain specific rules combined with partial a priori knowledge of mating parts geometry and interpreted force signals are used to reason and make inferences about the initial contact configuration. The likely contact surfaces are predicted and point(s) or line(s) of contact are fully defined. These surfaces are idealized and represented by quadratic equations or polyhedral surfaces. The geometric properties of surfaces at the contact location are used to select the contact configuration when multiple solutions exist.An algorithm for predicting the Expected Contact Configuration (ECC) has been developed and is illustrated here with examples. Experimental validation of the developed expert system prototype, using a 6R manipulator, a six-axis force sensor, and a host computer is described.     

On Confinement of the Initial Location of an Intruder in a Multi-robot Pursuit Game

Research in multi-robot pursuit-evasion demonstrates that three pursuers are sufficient to capture an intruder in a polygonal environment. However, this result requires the confined of the initial location of the intruder within the convex hull of the locations of the pursuers. In this study, we extend this result to alleviate this convexity through the application of a set of virtual goals that are independent of the locations of the pursuers. These virtual goals are solely calculated using the location information of the intruder such that whose locations confine the intruder within their convex hull at every execution cycle. We propose two strategies to coordinate the pursuers. They are the agents votes maximization and the profile matrix permutations strategies. We consider the time, the energy expended, and the distance traveled by the pursuers as metrics to analyze the performance of these strategies in contrast to three different allocation strategies. They are the probabilistic, the leader-follower, and the prioritization coordination strategies.     

Toward the development of interactive virtual dissection with haptic feedback

Traditional, hands-on dissection of an animal is common practice in many classrooms to aid in the study of anatomy and biology. More specifically, virtual dissection environments have been developed making it possible to study the inner workings of animals without cutting them up. In this paper, we present a novel virtual reality dissection simulator, where a user can dissect an animal (i.e. frog) and its organs using a 3D force feedback haptic device. The simulator uses force feedback as part of a multimodal cue to provide guidance and performance feedback to the user. This paper highlights methodologies which are used for addressing some of the key challenges involved in designing and developing simulators, such as: modelling and mechanics of deformation, collision detection between multiple deformable bodies, and haptic feedback.     

Interactive multi-modal suturing

We present a mechanics-based interactive multi-modal environment designed as part of a serious gaming platform. The specific objectives are to teach basic suturing and knotting techniques for simple skin or soft tissue wound closure. The pre-wound suturing target, skin, or deformable tissue is modeled as a modified mass-spring system. The suturing material is designed as a mechanics-based deformable linear object. Tools involved in a typical suturing procedures are also simulated. Collision management modules between the soft tissue and the needle, the soft tissue and the suture are analyzed. In addition to modeling the interactive environment of a typical suturing procedure, basics of the modeling approaches on the evaluation of a stitch formed by the user are also discussed. For example, if needle insertion points are too close from each other or to the edge of the wound, when the suture is pulled, the suture will tear the soft tissue instead of suturing the incision together. Experiment results show that our simulator can run on a standard personal computer and allow users to perform different suturing patterns with smooth graphics and haptic feedback.     

Cooperative hybrid multi-camera tracking for people surveillance

In this paper, a novel hybrid visual tracking system for event detection and people tracking is proposed. This surveillance system is composed of a stationary camera and a pan/tilt/zoom (PTZ) camera. The stationary camera has a wide field of view and detects fall and wandering events by means of motion-based visual tracking. The PTZ camera then tracks and follows the person who triggered an event using colour-based particle filtering. The purpose of tracking in view of the PTZ camera is to continuously keep the person in the camera view in order to obtain identifying details. Experimental results for event detection and people tracking are presented to demonstrate the proposed cooperative hybrid visual tracking system.     

siRNA nanotherapeutics: a promising strategy for anti‐HBV therapy

Chronic hepatitis B (CHB) is the most common cause of hepatocellular carcinoma (HCC) and liver cirrhosis worldwide. In spite of the numerous advances in the treatment of CHB, drugs and vaccines have failed because of many factors like complexity, resistance, toxicity, and heavy cost. New RNA interference (RNAi)‐based technologies have developed innovative strategies to target Achilles'' heel of the several hazardous diseases involving cancer, some genetic disease, autoimmune illnesses, and viral disorders particularly hepatitis B virus (HBV) infections. Naked siRNA delivery has serious challenges including failure to cross the cell membrane, susceptibility to the enzymatic digestion, and excretion by renal filtration, which ideally can be addressed by nanoparticle‐mediated delivery systems. cccDNA formation is a significant problem in obtaining HBV infections complete cure because of strength, durability, and lack of proper immune response. Nano‐siRNA drugs have a great potential to address this problem by silencing specific genes which are involved in cccDNA formation. In this article, the authors describe siRNA nanocarrier‐mediated delivery systems as a promising new strategy for HBV infections therapy. Simultaneously, the authors completely represent the clinical trials which use these strategies for treatment of the HBV infections.Inspec keywords: tumours, drugs, genetics, cellular biophysics, RNA, nanomedicine, diseases, molecular biophysics, microorganisms, cancer, liver, nanoparticles, patient treatmentOther keywords: siRNA nanotherapeutics, anti‐HBV therapy, chronic hepatitis B, CHB, HCC, hazardous diseases, cancer, genetic disease, autoimmune illnesses, viral disorders, hepatitis B virus infections, naked siRNA delivery, cell membrane, enzymatic digestion, renal filtration, nanoparticle‐mediated delivery systems, cccDNA formation, HBV infections complete cure, nanosiRNA drugs, siRNA nanocarrier‐mediated delivery systems, HBV infections therapy, liver cirrhosis, RNA interference, immune response, hepatocellular carcinoma     

Control strategies for rodotic contact tasks: An experimental study

In this article, we study the contact instability problem encountered in robotic manipulators while trying to make contact with an environment, such as grasping or pushing against objects, and propose a unified control strategy capable of achieving a stable contact against both stiff and compliant environments. The problem has three distinct stages of the contact task. In the first stage, free-space motion, the robot is approaching the environment; in the second stage, post-contact force regulation; in the third, impact stage, the transition from the first stage to the second. We make an experimental comparison of the control schemes that may be used for the three stages. For example, during impact, the manipulator should not lose contact with the environment, nor exert high impulsive forces on the environment, and in the post-impact phase, the robot should have a fast force trajectory tracking. The best strategies for the above stages are experimentally determined and then combined into a single unified controller that can achieve stable contact as well as a fast force trajectory tracking response for surfaces of variable stiffnesses. This control scheme does not require a priori knowledge of the stiffness of the environment, and is able to estimate the environmental stiffness and tune gains accordingly so as to achieve the best response. Also experimentally compared is the use of such a scheme with impedance control, another method proposed in the literature for robotic contact task control. © 1995 John Wiley & Sons, Inc.