Progressive Failure and Scale Effect of Trap-Door Problems with Granular Materials

Label-free immunosensors are well suited for detection of microorganisms because of their fast response and reasonable sensitivity comparable to infection doses of common pathogens. Active (lever oscillator and frequency counter) and passive (impedance analyzer) modes of quartz crystal microbalance (QCM) were used and compared for rapid detection of three strains of E. coli. Different approaches for antibody immobilization were compared, the immobilization of reduced antibody using Sulfo‐SMCC was most effective achieving the limit of detection (LOD) 8 × 104 CFU·mL−1 in 10 min. For the passive mode, software evaluating impedance characteristics in real-time was developed and used. Almost the same results were achieved using both active and passive modes confirming that the sensor properties are not limited by the frequency evaluation method but mainly by affinity of the antibody. Furthermore, reference measurements were done using surface plasmon resonance. Effect of condition of cells on signal was observed showing that cells ruptured by ultrasonication provided slightly higher signal changes than intact microbes.

A portable solar still's productivity boost combining a magnetic stirrer and thermoelectric

A PAM (pneumatic artificial muscle) bionic kangaroo leg suspension is proposed on the basis of a kangaroo leg structure evolved from long-term hopping; the modelling and characteristics research are conducted to pursue a high-performance vehicle suspension system. Based on the PAM and kangaroo leg bone proportions, the bionic suspension structure is constructed by analysing and refining the kangaroo leg structure and functions. The dynamic equations are derived by the Lagrange's Equations considering the rods system features and an Adams simulation model is built up to study the damping performance and parameter characteristics of the suspension. Moreover, a co-simulation of Adams and Matlab is performed under fuzzy control and PID control. The dynamic response characteristics of the suspension is simulated and analysed under the passive and active modes in the time and frequency domains. The result indicates that the vibration and shock of the vehicle body can be reduced effectively by the proposed suspension in passive, fuzzy control and PID control modes; compared with the passive mode, the damping performance of the suspension is better under the active control. The fuzzy control and the PID control are effective to reduce the suspension transmissibility, especially in the medium frequency ranges, and the two control effects are better than that of the passive mode in most frequency bands. The study result of this paper can provide a reference for the research and development of high-performance bionic suspension.

Most conventional vital-sign sensing techniques are incompatible with the circuits in commercial wireless communication devices. In addition, conventional techniques cannot easily provide both active and passive sensing. This article presents a novel active/passive dual-mode sensing technique for detecting vital signs. The proposed technique simply combines the error vector magnitude (EVM) algorithm with the demodulation of wireless communication to detect vital signs. Therefore, any wireless device can be used as a vital-sign sensor without any modification of their circuits. The proposed technique can switch between active and passive modes as desired. The experimental results show that the developed sensing technique is very effective in detecting vital signs. In active mode, the maximum vital-sign detection distances of the developed 2.4-GHz sensor are 4.3 and 9 m with and without a 15-cm-thick reinforced concrete wall as a barrier, respectively. In passive mode, the developed sensor can penetrate a 15-cm-thick reinforced concrete wall to detect human vital signs within a range of 6.3 m.

To study human motor control and learning in upper extremities, scientists widely use robotic arms to apply external forces to subject’s hand interactively. In this work, we describe the design procedure of a planar parallel manipulandum with five links and 2-DoF in a vertical plane (e.g. sagittal or frontal plane). The manipulandum works in two active and passive modes. In the passive mode, the robotic arm follows the movements of the human arm; while in the active mode, the robotic endeffector guides subject’s hand in any desired direction. In both active and passive conditions, the robot arm can be programmed to apply unexpected disturbances to the subjects hand. To control the movement of the manipulandum, we used two PID controllers with local shaft angle feedback to control the manipulandum. For the active mode, we used also a global feedback from endeffector position. As the first step for proof of concept, the whole system was simulated in MATLAB.

Mechanical ventilation is indispensable for patients with severe respiratory conditions, and high-fidelity lung simulators play a pivotal role in ventilator testing, clinical training, and respiratory research. However, most existing simulators are passive, single-lung models with limited and discrete control over respiratory mechanics, which constrains their ability to reproduce realistic breathing dynamics. To overcome these limitations, this study presents a dual-chamber lung simulator that can operate in both active and passive modes. The system integrates a sliding mode controller enhanced by a linear extended state observer, enabling the accurate replication of complex respiratory patterns. In active mode, the simulator allows for the precise tuning of respiratory muscle force profiles, lung compliance, and airway resistance to generate physiologically accurate flow and pressure waveforms. Notably, it can effectively simulate pathological conditions such as acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disease (COPD) by adjusting key parameters to mimic the characteristic respiratory mechanics of these disorders. Experimental results show that the absolute flow error remains within ±3 L/min, and the response time is under 200 ms, ensuring rapid and reliable performance. In passive mode, the simulator emulates ventilator-dependent conditions, providing continuous adjustability of lung compliance from 30 to 100 mL/O and airway resistance from 2.01 to 14.67, with compliance deviations limited to ±5%. This design facilitates fine, continuous modulation of key respiratory parameters, making the system well-suited for evaluating ventilator performance, conducting human–machine interaction studies, and simulating pathological respiratory states.

Monitoring of microwave emission of HRP system during the enzyme functioning

Sensitive measurements require a vibration isolation system to safeguard against detrimental tremble. Two types of vibration isolation systems - passive and active - are currently implemented. The spring-based passive designs usually accompany with ineffective low-frequency response. Therefore, the active designs, consisting of sensors, feedback control systems, and actuators, are consolidated to improve the total effectiveness of the cancellation performance. In this work, we focus on developing the actuator founded on electromagnetic spring to be incorporated into our compact quantum gravimeter. Each spring-actuated part comprises two repelling Nd magnets positioned face to face inside a solenoid. With this configuration, the spring can also work in the passive mode via repulsive magnetic force. In the active mode, the exerted force is a result of magnetic fields formed by the magnets and the current-controlled solenoid coils. By changing the coil current, the stiffness of the spring can be modified, and thus the displacement can be controlled. Different sizes of magnets are explored, and their force behaviors in passive and active modes are characterized. The implementation scheme of the actuator in the quantum gravimeter is also discussed.

A novel type of semi-active jet turbulence grid

The trap door problem is a useful model for providing a clearer understanding of the stress distribution around civil engineering structures such as anchor plates and tunnels. The passive mode can be used either to compute the uplift force of anchors or any buried structure which may be idealized as an anchor; the active mode can be used to compute the gravitational flow of a granular material between vertical walls or the soil reaction curve for tunnel design. Both modes of displacement are modelled numerically in this Paper using the finite element method. The results are presented in the form of influence charts, which may be used for both the passive and active modes to provide failure loads for a range of geometries and soil properties, using non-dimensionalized parameters. The use of these equations is compared with results obtained from other sources using both physical and numerical models. Le probleme de la trappe représente un modéle utile pour l'obtention d'une compréhension plus claire de la distribution des contraintes autour de structures du génie civil telles que les plaques d'ancrage et les tunnels. Le mode passif peut s'employer pour calculer la force d'arrachement des éléments d'ancrage ou d'une construction quel-conque ayant la fonction d'un element d'ancrage, tandis que le mode actif peut être utilisé pour calculer l'écoulement gravitationnel d'une matière granulée entre des murs verticaux ou la courbe de réaction du sol dans le cas d'un tunnel. Dans cet article les deux modes de déplacement sont model-és de fa&cidel;on numérique à l'aide de la méthode aux éléments finis. Les résultats sont présentés dans la forme de graphiques d'influence qui peuvent s'employer pour les modes passif et actif dans le but d'obtenir des chargements de rupture pour une serie de géométries et de propriétés du sol en uti-lisant des paramétres non-dimensionnes. L'emploi de ces équations est comparé aux résultats obtenus à partir d'autres sources en utilisant des modèles physiques et numériques.

Basic turn-taking and imitation skills are imperative for effective communication and social interaction (Nehaniv in Imitation and Social Learning in Robots, Springer, New York, 2007). Recently, research has demonstrated that interactive games using turn-taking and imitation have yielded positive results with autistic children who have impaired communication or social skills (Barakova and Brok in Proceedings of the 9th International Conference on Entertainment Computing, pp. 115–126, 2010). This paper describes a robot that plays interactive imitation games using hand and face tracking. The robot is equipped with a head and two arms, each with two degrees of freedom, and a camera. We trained a human hands detector and subsequently, used this detector along with a standard face tracker to create two autonomous interactive games: single-player (“Imitate Me, Imitate You”) and two-player (“Pass the Pose”.) Additionally, we implemented a third setting in which the robot is teleoperated by remote control. In “Imitate Me, Imitate You”, the robot has both passive and active game modes. In the passive mode, the robot waits for the child to initiate an interaction by raising one or both hands. In the second game mode, the robot initiates interactions. The “Pass the Pose” game engages two children in cooperative play by enlisting the robot as a mediator between two children alternately initiating and imitating poses. These games are designed to increase attention, promote turn-taking skills and encourage child-led verbal and non-verbal communication through simple imitative play. This research makes two specific contributions: (1) We present a low-cost robot design which measures and adapts to a child’s actions during interactive games and, (2) we train, test and make freely available, a new hand detector, based on Haar-like features, which is usable in various kinds of human-robot interactions. We present proof-of-concept experiments with a group of typically developing children.

We describe the positioning system of MAUVE, a miniaturized inexpensive underwater platform dedicated to the surveillance of coastal regions. MAUVE can navigate in three distinct modes (active, passive and inertial). In active mode position is directly observed, but energy consumption is non-negligible. In passive mode one component of position is not observable, however, it requires no additional energy. In inertial mode, positioning basically integrates on-board proprioceptive measures, leading to a strictly increasing error. We show that, by critically interleaving the use of these three modes, efficient tracking of a pre-specified trajectory can be achieved with a minimal penalty in consumed energy. Additionally, the paper proposes an autonomy monitoring indicator that flags the situations where vehicle recuperation can be in danger.

Primordial magnetic fields lead to non-Gaussian signals in the cosmic\nmicrowave background (CMB) even at the lowest order, as magnetic stresses and\nthe temperature anisotropy they induce depend quadratically on the magnetic\nfield. In contrast, CMB non-Gaussianity due to inflationary scalar\nperturbations arises only as a higher order effect. Apart from a compensated\nscalar mode, stochastic primordial magnetic fields also produce scalar\nanisotropic stress that remains uncompensated till neutrino decoupling. This\ngives rise to an adiabatic-like scalar perturbation mode that evolves passively\nthereafter (called the passive mode). We compute the CMB reduced bispectrum\n($b_{l_{_1}l_{_2}l_{_3}}$) induced by this passive mode, sourced via the\nSachs-Wolfe effect, on large angular scales. For any configuration of\nbispectrum, taking a partial sum over mode-coupling terms, we find a typical\nvalue of $l_1(l_1+1)l_3(l_3+1) b_{l_{_1}l_{_2}l_{_3}} \\sim 6-9 \\times\n10^{-16}$, for a magnetic field of $B_0 \\sim 3$ nG, assuming a nearly\nscale-invariant magnetic spectrum . We also evaluate, in full, the bispectrum\nfor the squeezed collinear configuration over all angular mode-coupling terms\nand find $l_1(l_1+1)l_3(l_3+1) b_{l_{_1}l_{_2}l_{_3}} \\approx -1.4 \\times\n10^{-16}$. These values are more than $\\sim 10^6$ times larger than the\npreviously calculated magnetic compensated scalar mode CMB bispectrum.\nObservational limits on the bispectrum from WMAP7 data allow us to set upper\nlimits of $B_0 \\sim 2$ nG on the present value of the cosmic magnetic field of\nprimordial origin. This is over 10 times more stringent than earlier limits on\n$B_0$ based on the compensated mode bispectrum.\n

Assistive robotic rehabilitation can be classified into two groups, the passive mode where the robot moves the patient’s affected member along the desired movement, and the assisted as needed mode, where the subject performs the exercises by himself and the robot interacts only to guarantee the accuracy of the movement. This paper proposes an optimal design of a 3-DoF planar cable-driven parallel robot intended for upper limb rehabilitation as well as the torque control strategies adopted for the assisted as needed and the passive rehabilitation modes. In this context, a motion capture system was carried out for the desired trajectories and the measured data were analyzed in order to extract the robot prescribed workspace.KeywordsPassive modeAssisted as needed modeOptimal designPlanar cable-driven parallel robotTorque control strategies

Granular materials: constitutive equations and strain localization