Electrical impedance tomography: a potential tool for intraoperative imaging of the tongue base

The presence of a tumor in the tongue is a pathology that requires surgical intervention from a certain stage. This type of surgery is difficult to perform because of the limited space available around the base of the tongue for the insertion of surgical tools. During the procedure, the surgeon has to stretch and then fix the tongue firmly in order to optimize the available space and prevent tissue movement. As a result, the preoperative images of the inside of the tongue no longer give a reliable indication of the position and shape of the cancerous tissue due to the deformation of the overall tissue in the area. Thus, new images are needed during the operation, but are very difficult to obtain using conventional techniques due to the presence of surgical tools. Electrical Impedance Tomography (EIT) is an imaging technique that maps the resistivity or difference of resistivity of biological tissues from electrical signals. The small size of the electrodes makes it a potentially interesting tool to obtain intraoperative images of the inside of the tongue. In this paper, the possibility of using EIT for this purpose is investigated. A detection method is proposed, including an original configuration of the electrodes, consistent with the anatomical specificities of the tongue. The proposed method is studied in simulation and then a proof of concept is obtained experimentally on a 3D printed test tank filled with saline solution and plant fibres.

Reconnecting groups of space debris to their parent body through proper elements

Satellite collisions or fragmentations generate a huge number of space debris; over time, the fragments might get dispersed, making it difficult to associate them to the configuration at break-up. In this work, we present a procedure to back-trace the debris, reconnecting them to their original configuration. To this end, we compute the proper elements, namely dynamical quantities which stay nearly constant over time. While the osculating elements might spread and lose connection with the values at break-up, the proper elements, which have been already successfully used to identify asteroid families, retain the dynamical features of the original configuration. We show the efficacy of the procedure, based on a hierarchical implementation of perturbation theory, by analyzing the following four different case studies associated to satellites that underwent a catastrophic event: Ariane 44lp, Atlas V Centaur, CZ-3, Titan IIIc Transtage. The link between (initial and final) osculating and proper elements is evaluated through tools of statistical data analysis. The results show that proper elements allow one to reconnect the fragments to their parent body.

Scheimpflug Topography Oriented Adequate Repositioning of a Misaligned Free Flap after Laser in situ Keratomileusis

This report describes a case of Scheimpflug topography oriented adequate repositioning of a misaligned thick free flap after laser in situ keratomileusis (LASIK). A 24-year-old patient consulted for irregular astigmatism and disoriented free right eye flap. The patient previously underwent binocular LASIK at a private clinic. During the right eye surgery, the flap was repositioned after laser ablation due to the free flap. The free flap was not repositioned to its original configuration due to insufficient preoperative corneal marking. On examination, the uncorrected visual acuity was 0.4, and refractive power was +2.00 Dsph with −4.25 Dcyl axis 66 in the right eye. Scheimpflug topography revealed irregular right eye astigmatism. The sagittal curvature of topography showed a 40° counterclockwise misalignment of the steep axis of the cornea. The free flap was repositioned by 40° clockwise rotation. After this, the refractive corneal power improved to −1.00 Dsph with −1.00 Dcyl Axis 19 in the right eye. The uncorrected and best-corrected visual acuity improved to 20/30 and 20/25 (x − 0.25Dsph −1.25 Dcyl A20), respectively. This is the first report on free flap repositioning using Scheimpflug topography. As proper flap positioning was compromised because of the free LASIK flap with no preoperative corneal marking, the flap was effectively repositioned using Scheimpflug topography.

Perceptual Organisation Affects Perception and Appreciation of Abstract Art: A Case Study with Black Square and Red Square by Kazimir Malevich

Perceptual organisation is hypothesised as a key in the perception and appreciation of abstract art. Here, we investigated how relational and compositional features affected the perception and aesthetic appreciation of Black Square and Red Square by Kazimir Malevich (1915). We studied how (i) the presence and obliquity of the red square and (ii) the relative configuration of the black and red square affected the detectability of the obliquity of the black square in this artwork. Results showed that the simultaneous presence and obliquity of the red square masked the obliquity of the original black square. The likelihood of the black square being incorrectly perceived as an exact square was always maximum in the original configuration and even slight alterations in the original configuration of the work resulted in the obliquity of the black square to be noticed. The original artwork was more aesthetically preferred compared to its alternatives. We argue that the artist may have intentionally set the configuration to mask the obliquity of the black square and maximise the aesthetic preference.

A GRAMMAR BASED METHODOLOGY TO SUPPORT THE ADAPTIVE REUSE OF HISTORIC BUILDINGS: THE CASE STUDY OF THE SOBRADO BUILDING TYPE

The historical center of São Luís is host to a diverse historic and urban ensemble, reminiscent of the 18th and 19th centuries. The architectural typology which can be found there illustrates the strong influence drawn from the Portuguese style known as Pombalino, developed during the reconstruction process of Lisbon after the 1755 earthquake. Due to the historical relevance of these buildings which encapsulate this period in time, it is important to preserve and maintain the buildings located in this region. Adaptive reuse projects have an important role to play in preserving architectural ensembles like this. The first part of the adaptive process is to document and understand the original configuration of the building with the aim of maintaining the elements with historical relevance. Therefore, this project proposes the use of a shape grammar approach to analyze floor plans, aiming to further contribute to adaptive reuse projects for ‘Sobrado’ buildings. The process focuses specifically on a case study building and aims to document and identify the specific placement of elements in the floor plan in an effort to provide a deeper understanding of future adaptive reuse.

Design and Kinematic Simulation of a Novel Leg Mechanism for Multi-Legged Robots

Among mobile robotic research field, legged locomotion is largely applied for advanced robotic systems due to the higher degree of versatility compared to wheeled robots, which allows them to successfully move and interact in unstructured environments; nevertheless, legged robots present several designing problems and require a much more complex control system. Based on an effective robotic leg, this paper presents a novel design, which integrates a cam joint, aimed to improve the versatility performances minimizing changes in the original model and without increasing the control complexity. Furthermore, the design strategy aims to exploit the coupled action of two actuators, which are disposed in a novel configuration so to gain versatility advantage while maintaining velocity performances of legs equipped with a single actuator. The model is presented through a kinematic analysis, followed by the simulation of the leg mechanism trajectory and a comparison with the original configuration.

Performance of an agricultural engine using turbocharger and intercooler

This paper aimed to evaluate the effects of air and fuel supercharging in an agricultural engine. The analyzed variables consisted of torque, power, and specific fuel consumption. Tests were carried out using a dynamometer through the power take-off of an agricultural tractor. The experiment was carried out at a laboratory in a completely randomized design arranged under a two-factorial scheme, with three replications. Six engine configurations (natural aspiration, natural aspiration + service, turbocharger, turbocharger + service, turbocharger + intercooler, and turbocharger + service + intercooler) and 10 engine speeds (1,200, 1,300, 1,400, 1,500, 1,600, 1,700, 1,800, 1,900, 2,000, and 2,100 rpm) were evaluated. The turbocharger alone did not increase engine torque and power. The increase in fuel flow enhanced engine performance for the evaluated configurations. Turbocharger + service and turbocharger + service + intercooler configurations reduced specific fuel consumption by up to 10% and increased torque and power by approximately 30% compared to the original configuration (natural aspiration).

Comparative analysis of cylindrical and planar aesa in 3d suveillance radar.

A modern rotating 3D surveillance radars scan azimuth by mechanical rotation, and scan elevation using Active Electronic Scanning Array (AESA) in Multi Beam Receive Mode (MBM). Radars with fixed cylindrical AESA and four-sided prismatic antenna, with 4 flat AESA, scan azimuth electronically, without mechanical rotation. The most significant advantage of electronic scanning is the possibility of Multi-mode operation: surveillance targets in the far zone and targeting targets in the near zone. However, electronic scanning also brings problems. A main beam of planar AESA spreads and lateral lobes increase when the radiating direction increases. An original arrangement of shifted array to reduce lateral lobes has been proposed. The cylindrical array has a constant shape of pattern during azimuth scanning. But, for both prismatic and cylindrical AESA, the beam deforms during scanning in vertical plane, so limits the elevation scan. Also, the complexity and price of fixed AESA is significantly higher compared to the rotating one. In order to enable the selection of the optimal solution for a specific application, the comparative analysis of advantages and disadvantages for cylindrical, prismatic and rotating AESA is done. The original configuration of the cylindrical AESA for Very Fast Scanning in Near-zone has been proposed.

Optimal Design of Tuned Mass Damper Inerter for Base-Isolated Buildings

Tuned mass dampers (TMD) are installed in base-isolated building to suppress the excessive isolator displacement and acceleration responses of primary structure. By incorporating an inerter element into the original configuration, the seismic performance of TMD is significantly enhanced. In this work, optimal solutions of tuned mass damper inerter (TMDI) for improving the seismic resilience of base-isolated building are proposed. The analytical formulations of optimal design of TMDI are respectively developed to minimize the H2 norm of the displacement of primary structure relative to the base floor and the isolator displacement. The performance of presented optimal methods are validated by using stationary responses under the stochastic excitations. Additionally, the seismic performance of TMDI with parameters obtained from the proposed method are compared with the established methods.

Fuel efficiency optimization of high-aspect-ratio aircraft via variable camber technology considering aeroelasticity

In this study, variable camber technology is applied to improve the fuel efficiency of high-aspect-ratio aircraft with aeroelasticity considered. The nonlinear static aeroelastic analyses are conducted for CFD/CSD (computational fluid dynamics/computational structural dynamics) numerical simulations. The RBF (radial basis function) method is adopted for the transmission of aerodynamic loads and structural displacements, the diffusion smoothing method is employed for grid deformation in each iteration of CFD/CSD coupling, and the FFD (free-form deformation) method is introduced for the parameterization of variable camber wing. Based on the aerodynamic characteristic curves under different cambers, the discrete variable camber control matrix for the high-aspect-ratio aircraft during the cruise phase is established. The Fibonacci method is employed to optimize the fuel efficiency by utilizing the control matrix. The results indicate that the drag during the cruise phase is reduced obviously and the fuel efficiency is improved evidently comparing to the original configuration.