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The research aimed to evaluate the efficacy of the NeuroAssist, a parallel robotic system comprised of three robotic modules equipped with human–robot interaction capabilities, an internal sensor system for torque monitoring, and an external sensor system for real-time patient monitoring for the motor rehabilitation of the shoulder, elbow, and wrist. The study enrolled 10 consecutive patients with right upper limb paresis caused by stroke, traumatic spinal cord disease, or multiple sclerosis admitted to the Neurology I Department of Cluj-Napoca Emergency County Hospital. The patients were evaluated clinically and electrophysiologically before (T1) and after the intervention (T2). The intervention consisted of five consecutive daily sessions of 30–45 min each of 30 passive repetitive movements performed with the robot. There were significant differences (Wilcoxon signed-rank test) between baseline and end-point clinical parameters, specifically for the Barthel Index (53.00 ± 37.72 vs. 60.50 ± 36.39, p = 0.016) and Activities of Daily Living Index (4.70 ± 3.43 vs. 5.50 ± 3.80, p = 0.038). The goniometric parameters improved: shoulder flexion (70.00 ± 56.61 vs. 80.00 ± 63.59, p = 0.026); wrist flexion/extension (34.00 ± 28.75 vs. 42.50 ± 33.7, p = 0.042)/(30.00 ± 22.97 vs. 41.00 ± 30.62, p = 0.042); ulnar deviation (23.50 ± 19.44 vs. 33.50 ± 24.15, p = 0.027); and radial deviation (17.50 ± 18.14 vs. 27.00 ± 24.85, p = 0.027). There was a difference in muscle activation of the extensor digitorum communis muscle (1.00 ± 0.94 vs. 1.40 ± 1.17, p = 0.046). The optimized and dependable NeuroAssist Robotic System improved shoulder and wrist range of motion and functional scores, regardless of the cause of the motor deficit. However, further investigations are necessary to establish its definite role in motor recovery.

The aim of this work is to study the physical-chemical, mechanical, and biocompatible properties of hydroxyapatite obtained by hydrothermal synthesis, at relatively low temperatures and high pressures, starting from natural sources (Rapana whelk shells), knowing that these properties influence the behavior of nanostructured materials in cells or tissues. Thus, hydroxyapatite nanopowders were characterized by chemical analysis, Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). In vitro studies on osteoblast cell lines (cytotoxicity and cell proliferation), as well as preliminary mechanical tests, have been performed. The results showed that the obtained powders have a crystallite size below 50 nm and particle size less than 100 nm, demonstrating that hydrothermal synthesis led to hydroxyapatite nanocrystalline powders, with a Ca:P ratio close to the stoichiometric ratio and a controlled morphology (spherical particle aggregates). The tensile strength of HAp samples sintered at 1100 °C/90 min varies between 37.6–39.1 N/mm2. HAp samples sintered at 1300 °C/120 min provide better results for the investigated mechanical properties. The coefficient of friction has an appropriate value for biomechanical applications. The results of cell viability showed that the cytotoxic effect is low for all tested samples. Better cell proliferation is observed for osteoblasts grown on square samples.

The solid waste of Rapana thomasiana seashells both from domestic activities and natural waste on seashore can be used to obtain viable products for medical applications. However, conventional technologies applied for sintering the materials require massive energy consumption due to the resistance heating. Microwave heating represents an advanced technology for sintering, but the stability of the process, in terms of thermal runaway and microwave plasma arc discharge, jeopardizes the quality of the sintered products. This paper aims to present the results of research focused on viable heating technology and the mechanical properties of the final products. A comparative analysis, in terms of energy efficiency vs. mechanical properties, has been performed for three different heating technologies: direct microwave heating, hybrid microwave heating and resistance heating. The results obtained concluded that the hybrid microwave heating led to final products from Rapana thomasiana solid waste with similar mechanical properties compared with resistance heating. In terms of energy efficiency, the hybrid microwave heating was 20 times better than resistance heating.

Robots for rehabilitation tasks require a high degree of safety for the interaction with both the patients and for the operators. In particular, high safety is a stable and intuitive control of the moving elements of the system combined with an external system of sensors able to monitor the position of every aspect of the rehabilitation system (operator, robot, and patient) and overcome in a certain measure all the events that may occur during the robotic rehabilitation procedure. This paper presents the development of an internal torque monitoring system for ASPIRE. This is a parallel robot designed for shoulder rehabilitation, which enables the use of strategies towards developing a HRI (human–robot interaction) system for the therapy. A complete analysis regarding the components of the robotic system is carried out with the purpose of determining the dynamic behavior of the system. Next, the proposed torque monitoring system is developed with respect to the previously obtained data. Several experimental tests are performed using healthy subjects being equipped with a series of biomedical sensors with the purpose of validating the proposed torque monitoring strategy and, at the same time, to satisfy the degree of safety that is requested by the medical procedure.

This paper presents the design of an innovative robotic system for lower limb post-stroke rehabilitation of bed confined patients during the acute stage of the treatment. To establish the particularities of each targeted joint motion, experimental measurements are performed on healthy subjects. The acquired data is used to determine the operational workspace, namely the limits of the anatomic joints motion for the lower limb. Based on the prescribed operational workspace, an innovative parallel robotic architecture is designed for achieving the rehabilitation of the lower limb. A detailed kinematic modelling and analysis is carried out to demonstrate the robot capability to safely achieve the required motions. The design of the robotic rehabilitation device is discussed in detail alongside with numerical simulations for validating its performance while performing medically relevant rehabilitation motions.

The first objective of this paper is to study the influence of the orthotic device on the maximum values of stresses in knee cartilages by using Ansys Workbench 14.5 software and applying the Finite Element Analysis (FEA) on a virtual assembly composed by an orthotic device and osteoarthritic knee (OAK). The second objective consists into quantifying and investigating the nonlinear motion of the human knee joint for OAK patients, with and without the orthotic device mounted on OAK, using tools of dynamics stability analysis. The short Lyapunov Exponents (LEs) are calculated, as measures of human knee and ankle joints stability, based on the experimental time series collected by using the biometrics acquisition system during walking on horizontal and inclined treadmills from a sample of healthy subjects and a sample of patients suffering by OAK disease. The values of LEs obtained for OAK patients are larger on the inclined treadmill than on horizontal treadmill and are larger than those obtained for healthy knees, being associated with more divergence and less stability. The results confirm that the influence of an orthotic device mounted on OAK on its stability is significant, the values obtained for LEs being smaller than those calculated for OAK, and closer to the values of normal knees of patients and of healthy subjects.

In this paper, we present a new exoskeleton robot model designed to assist human locomotion. In the first part of the paper are presented results concerning human gait motion analysis. The human gait experimental analysis is performed with goniometers sensors. In the second part of the paper are presented some structural solutions for exoskeleton robots, presented by first author in other published papers. Based on these achievements, new exoskeleton robot designs are proposed. The kinematic structure of the new robot is presented. The designed robot assures motion assistance for all the leg joints, and it is actuated with one drive. Based on this kinematic structure, the robot is modeled in the CAD design environment, SolidWorks, and the motion simulation is performed in the MSC.ADAMS simulation environment. The graphs of variation of the kinematic and dynamic parameters of the robot are presented. The exoskeleton motion results are compared with those from the human normal gait.

The purpose of this study was to estimate Lyapunov exponents (LE) in order to quantify the local dynamic stability of the lower limb joints during sit-to-stand movement. The values of the Lyapunov exponents are obtained based on the experimental time series of the flexion-extension movements in sagittal plane and the rotational movements in frontal plane for all six main joints of both lower limbs, collected from a sample of healthy subjects and a sample of patients suffering by knee osteoarthritis before total knee replacement. The values of LEs obtained for the osteoarthritic lower limb are associated with more divergence and less stability, being generally, larger than those obtained for the other patient’ limb, and larger than those of healthy joints.

The aim of this study is to measure the variation of the flexion-extension angles of the knee and to study the stability of the knees movements during ascending and descending the stairs for healthy subjects and for patients suffering of osteoarthritic knee (OAK). Tools of nonlinear dynamics are used in order to quantify the stability of human healthy knee and OAK joints during ascending and descending the stairs. The values of Lyapunov exponents (LE), which represent the measure of instability of knee movements, are computed based on the experimental time series collected for both knee joints movements: flexion-extension (fl-ext) in sagittal plane and varus-valgus rotation (var-valg) in frontal plane. LEs obtained for the OAK are associated with more divergence, more variability and less stability, being larger than those are obtained for the knees of healthy subjects.

The inland navigation sector makes a significant contribution to the growth of the global economy as well as to climate change due to pollutants emitted by diesel engines. NOx emissions are very high in port areas where, due to traffic, the ships run at idling regimes. Selective catalytic reduction (SCR) represents one of the most suitable technologies, in terms of cost effectiveness, but does not perform well if the temperature during vessel operation is lower than 180 °C. Microwave technology can support preheating of the ceramic core of SCR in order to increase the temperature towards the optimal interval for the best NOx reduction. Research has focused on coupling a magnetron head to a SCR device in order to evaluate to what extent the technology can meet the requirements of Stage V of the European Directive related to NOx emissions. Measurements of NOx emitted have been performed on engines with 603.5 kW nominal power and 1500 rpm that operate at a lower engine speed (700–1200 rpm) and output power (58–418 kW). The values recorded for emissions using microwave heating of ceramic core of SCR have decreased by 89% for a constant load of engine and idling engine speed.

This work addresses the design and numerical characterization of a new exoskeleton solution for human leg motion assistance and rehabilitation. The exoskeleton solution is anthropomorphic, simple, low cost and easy to adapt on the human subject. The design aspect concerns the exoskeleton mechatronic structure, achieved in SolidWorks virtual environment. Numerical simulation is performed in MSC.ADAMS simulation environment. Obtained results for the exoskeleton computed motion are compared with those obtained from experimental walking of healthy subject. The prototype feasibility is studied both for design and operation aspect.

The first objective of this paper is to study the influence of a prosthesis on the maximum values of contact stresses developed in the components of the virtual model of a prosthetic knee assembly, using Finite element analysis (FEA). The second objective is to estimate Lyapunov exponents (LEs) in order to quantify the local dynamic stability of the human knee joint during walking overground for healthy subjects and for patients suffering of osteoarthritic knee (OAK), before and after total knee replacement (TKR), using tools of dynamics stability analysis. The values of the LEs are obtained based on the experimental time series of the flexion-extension movements in sagittal plane and the rotational movements in frontal plane for both knees, collected from a sample of healthy subjects and a sample of patients suffering by OAK before and after TKR. The influence of prosthesis mounted in OAK is positive, the values of LEs obtained for OAK four month after TKR are associated with increased stability, being smaller than those computed for OAK before TKR, and closer than those obtained for healthy knees.

The present paper presents the main wearable sensors used in order to monitor the human gait, to monitor the training and performance in sports, to monitor the normal and pathological human gait, as well as the movements of the driver and the occupants of the car during driving.

The Latitude Prosthesis is a complex implant for human elbow joint with a great constructional flexibility, providing the possibility, depending on the intraoperative situation and the residual instability, to “move” intra-operatively from a non-constrained prosthesis to a constrained prosthesis by a piece attached to the component ulnar. This study aims to present the virtual modeling of the Latitude elbow prosthesis and of the human elbow joint-Latitude prosthesis assembly. The kinematic simulation of the flexion-extension and pronation-supination movements of the elbow joint-Latitude prosthesis–assembly are performed.

This paper presents a study concerning the structural and mechanical design in Solid Works completed with a kinematic numerical description for a new leg exoskeleton proposed for human motion assistance and rehabilitation. The exoskeleton proposed new design is based on a seven links mechanism, designed to fulfil human locomotion tasks. A kinematic model of the proposed mechanism is presented and obtained results with a computational algorithm developed in ADAMS, are presented with plots. A 3D model is designed for simulation purposes in ADAMS multi body dynamics software and future manufacturing. The obtained simulation results are useful to appreciate the exoskeleton performance for human rehabilitation purposes.

In shape memory alloys (SMAs), the thermoelastic martensitic transformation between austenite and martensite phases leads to the appearance of the shape memory effect and super-elasticity. In addition, these alloys present high mechanical strength, great ductility, vibration damping property and hysteresis behavior. All of the above-mentioned properties make these alloys very promising for industrial applications and their usage leads to the increase of productivity and efficiency of the devices they pertain to. The purpose of this article is, on the one hand, to increase the awareness of R & D engineers about the existence and use of SMAs by describing and promoting the unusual properties and effects of these materials and, on the other hand, to outline some of their most promising industrial applications.

In this paper finite-time Lyapunov exponents were estimated in order to quantify the local dynamic stability, based on the experimental time series of the flexion-extension and inversion-eversion angles of ankle joints, obtained from a group of five subjects with normal left ankles and right ankles suffering by repeated sprains with residual laxities walking over-ground and on plane and inclined treadmill with different speeds and inclinations.

In this study, a new exoskeleton leg design for the human motion assistance and rehabilitation use is proposed. The structural solution of the leg mechanism is analysed and a mechanical design solution is developed in Solid Works. The 3D model is used for design optimization and simulation purposes. The study of the leg mechanism is complete with a kinematic analysis, solved with a computational algorithm in Mathlab software, in order to obtain numerical results with plots. The rehabilitation exoskeleton is based on a five links planar mechanism, and design to fulfil human main locomotion tasks. A proper dynamic model of the proposed rehabilitation exoskeleton system is build in ADAMS multi body dynamics software and used to obtain numerical results for exoskeleton motion parameters with plots. These results consist in motion parameters of the exoskeleton solution and exoskeleton gait trajectories, being very useful to appreciate the exoskeleton feasibility and usefulness for human motion assistance and rehabilitation purposes.

To generate a virtual human hip is a main goal for our research team. Also, starting from the normal virtual hip joint and using the important orthopedics information was defined the affected hip joint. All these models were generated in a 3D virtual environment starting with CT scanning images. Using an original method all the scanned CT images were re-defined and re-drawn and transferred to the 3D software. The resulted curves were used to generate the bones and the virtual complex system of both hip joints. With motion and geometric constrains the bio-mechanical assemblies were defined, starting from anatomical information. The normal hip joint and the model of the affected hip were defined and exported to ANSYS, software based on Finite element analysis.

In this paper, using 3D finite element method and starting from the virtual model of the human knee joint-prosthesis assembly, we investigate the effects of antero-posterior tibial slope on contact stresses in the three components of total knee prosthesis. Using AnsysWorkbench15.07 software, the stress and displacements maps are obtained for knee-prosthesis assemblies and for their components, considering two loading force: 800N and 2400N and two cases of prosthetic knee varus slope: 176o and b) 191o. For each prosthesis-knee assembly and for each considered force, two variants of antero-posterior tibial slope were considered: 00 and 50.

In this paper the effects of varus tilt on contact stresses in the three components of total knee prostheses using 3D finite element analysis were investigated. Using Ansys simulation environment, six complex virtual models of human knee joint–prosthesis assembly obtained for six different varus tilts which increase from 176o to 191o, with an increment of 3o have been subjected to finite element analysis in order to obtain the stress maps and total displacements maps.

In this paper the knee joint biomechanics during squat exercises is studied. Using an acquisition system based on electro-goniometers, measurements of flexion-extension knee angle during squat movement on a sample group of healthy subjects are performed. For each subject the curves of knee squat angle are normalized and the mean squat cycle of each subject and the final medium cycle are determined. The phase plane portraits are used to characterize the kinematics of the biomechanical system. Using ADAMS software, the forces components and the resultant connection force during squat cycle in the human knee joint are determined.

The paper presents the results of the authors concerning the experimental human walking and numerical simulation of human rehabilitation on a treadmill. Using Biometrics data acquisition system based on electrogoniometers, experimental measurements for ankle, knee and hip joints of right and left legs during walking on plane and inclined treadmill are performed. The human legs motion assistance for rehabilitation is proposed with an attached exoskeleton. The numerical simulation of a virtual mannequin walking with the attached exoskeleton on a plane and inclined treadmill is performed, using ADAMS virtual environment. A comparison between human experimental measurements and numerical simulations of a virtual mannequin with exoskeleton is presented.

The use of Shape Memory Alloy (SMA) materials for actuation represents a technological opportunity for the development of innovative applications. The issue of using the SMA actuators is an enticing solution that has attracted the interest of specialists in recent years, due to their numerous advantages (i.e. reliability, compactness and flexibility, reduced cost, linear or angular movement etc.). In addition, their unmatched energy density, easy integration into various structures and the simplicity in terms of design, have all motivated the authors to develop a barrier structure model, actuated by three SMA helical springs. The actuator used in this structure works as a linear actuator, contracting with great strength and speed, thus exerting the necessary force to lift the barrier arm in the SMA springs heat-activated, austenitic state. The first part of this paper provides a description of the accomplished model and of its functioning principle. The second part of the study presented in this paper focuses on the authors' investigation on how the performances of the actuator inserted in the barrier structure—namely the actuator's heating time, cooling time, actuation time and stroke—are affected by the SMA spring activating direct current values. The tests were conducted while keeping the geometrical parameters of SMA springs and the weight of the barrier arm constant.

The aim of this paper is to compare the range of motion of the sit-to-stand (STS) movement angles for the both knees: osteoarthritic (OA) left knee and healthy right knee, for seven subjects who performed an experimental test consisting of STS cycles on a chair. The acquisition system consists of two electro-goniometers, one for each leg, for making possible the simultaneously reading of data during experiments. The angular amplitudes of human knee flexion-extension during the STS cycles are obtained as data files. For each knee of all subjects were selected 8 consecutive cycles which were normalized by interpolation with cubic Spline functions, using MATLAB environment. The final medium STS cycle for both knees is obtained. Finally, statistical analyses are made and the results are presented. The maximum values of the knee angle for both knees of all seven subjects were compared and tested with an unpaired Student t-test, considering α=0.05. The p-values corresponding to this test are calculated using ANOVA. Based on the average anthropometric data the virtual model of a mannequin using SolidWorks software was developed, and then was transferred to ADAMS simulation environment in order to obtain the variation laws of reaction forces in the lower limb joints.

This paper presents advanced modeling and simulation methods, using the latest generation of CAD-CAE applications. For the geometric modeling of human knee joint embedded applications as DesignModeler, SpaceClaim under Ansys Workbench software package were used. The objective of this study is to present our contributions on the modeling, simulations and finite element analysis of the healthy and osteoarthritic human knee joint in order to quantify and investigate its biomechanical behavior. The main objective of this article is to present a complex three-dimensional model of the healthy knee joint and of the osteoarthritic joint which shows a 15otilt in varus, the joint being affected by osteoarthritis in both compartments, in order to predict stresses and displacements in their individual components. The applied forces were equal with 800 N and 1500 N. Finally the results obtained for normal knee and for OA knee joint are compared.

The research for an ideal hip prosthesis has led to the development of several durable materials that have been tested very intensly during the past decades, both clinically and mechanically. Alumina on alumina bearing has proven to be a very reliable bearing and is used more and more often. Nevertheless, because of the lack of ductility of alumina ceramic, concerns have been raised regarding its risk of fracture. The purpose of our study is to evaluate the mid-term results (78 months follow-up) of alumina on alumina prosthesis and the complications that have appeared regarding to the properties of the implant. We have reviewed retrospectively 89 THA performed in our clinic during October 2005 – October 2013 on a follow-up period of maximum 78 months. The mean age of the patients included was 49,60 years for men and 48,44 years for women. It was used a single kind of implant with same type of alumina parts, applied only on a postero-lateral surgical approach. The survival rate of ceramic-on-ceramic bearing surface by itself was 98.87% (88 out of 89). The most frequent complication was the dislocation of the prosthesis that happened in 7 cases, mainly due to a malposition of the acetabular cup, without any damage done to the ceramic bearing surfaces. In the failed case we have encountered a cracked femoral head that has been previously resterilized by steam. We could conclude that the alumina on alumina prosthesis is a very reliable prosthesis regarding its durability and strength. It requires a very precise surgical technique when implanted, since almost all the complications were due to a malposition of the acetabular component. A postero-lateral wall of the liner might decrease the rate of dislocations and ceramic wear. Also, we might debate that the steam sterilization is not suitable for alumina implants, since the fractured femoral head was resterilized.

The paper presents a complex three-dimensional model of the human knee joint, containing bones, ligaments, menisci, tibial and femoral cartilages. To investigate the role of the articular cartilage in the developing of the osteoarthritis, to analyze and simulate the biomechanical behavior of the human knee joint, a finite element analysis was performed. The non-linearities are due to the presence of the contact elements modeled between components surfaces and to the nonlinear properties of the cartilage, applying a load of 800 N and 1500 N, for 0o in flexion. The results show that misalignment (valgus variation) could damage the articular cartilage because they increase the stress magnitude, that progressively produce articular cartilage damage and it enhances the osteoarthritis phenomenon due to mechanical factors. The displacements and the Von Mises stress distributions on the cartilage and menisci for the virtual prototype, considering an angle of 10 degrees for valgus, are presented. The obtained values are comparable with the values obtained by other authors.