Search

This paper presents the closed loop teleoperation of a minimal surgery training system using haptic and robot devices. The force tracking performances of system can be improved by using dynamic compensation and fuzzy control. In this system, the master is the 6-DOF haptic device and the slave is the 6-DOF serial robot. The master haptic device provides the trajectories for the slave serial robot throught the operation of user's hand on the steering handle while the slave robot sends feedback forces on its end effector to the master controller in order to generate forces/moments on the steering handle of haptic master. In this manner the user's hand will feel the forces/moments as the same those of the robot end effector. Because dynamics of the master haptic device affects directly to the performances of control actions, it should be calculated to compensate in the control algorithms. Inverse dynamics combined with fuzzy control is used to compensate for actual dynamics of the haptic master in the real closed loop teleoperation system. Experiment results indicate that the dynamic compensation and fuzzy control can improve the control performances effectively.

The density and refractive index of diluted binary mixtures of active carbon and exfoliated graphite nanoplatelets dispersed in N,N-dimethylformamide were measured at different temperatures, and the ultrasound speed through these materials was determined. From the experimental results, acoustic parameters such as the acoustic impedance, isentropic compressibility, specific refraction, space-filling factor, and relaxation strength were estimated for all compositions and temperatures. The results were used to identify molecular interactions in the mixtures, including structural changes of exfoliated graphite nanoplatelets in polar solvents.

To evaluate the effect of crop residue burning of agriculturally tilled soils, the soil's sorption of polycyclic aromatic hydrocarbons (PAHs) is studied using naphthalene as a representative model contaminant in the soil. Soils from agriculturally tilled fields (Dorobantu farm, Calarasi, Romania), either burned or unburned for clearance, were examined for their toxicity and sorption capacity (fields being burned for cleansing experience an increase in nanoparticles because soot particles enter the soil). The burned and unburned soils were separated into several fractions on the basis of size using membranes with different pore sizes. Batch experiments were conducted to test the impact of the following operating parameters: the initial concentration of naphthalene, initial concentration of soil, pH, soil structure and composition and soil characterization. The toxic effectiveness of the various soils was also investigated.

A surface amino-functionalized ( CO NH2) exfoliated graphite nanoplatelet (xGnP) bismuth-modified electrode ( CO NH2 xGnP/glassy carbon electrode GCE) for the determination of lead was developed and characterized. The hybrid material was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The electrochemical properties of the CO NH2 xGnP bismuth-modified electrode were characterized by a physical deposition method, depositing the film on a graphite electrode. The differential pulse response was linear over the Pb(II) concentration range of 0.005–0.045 μg L−1, with a limit of detection of 0.001 μg L−1, and the linear regression equation was y = 3.75x + 0.73. In vegetable juice (cabbage), the current increased linearly relative to the Pb(II) concentrations over the concentration range 0.005–0.035 μg L−1 with the corresponding linear regression equations: y = 13.06x + 0.46, R2 = 0.9970.

The widespread use of organophosphate pesticides (OPPs) in agriculture leads to residue accumulation in the environment, which is dangerous to human health and disrupts the ecological balance. This study reports results obtained by a standard chromatographic method (high performance liquid chromatography, HPLC) and an amperometric method for chlorpyriphos (CPF) determination in broccoli. Reversed-phase HPLC with UV–VIS detection was used for the separation, and the mobile phase was acetonitrile–water (75:25 v/v). The electrochemical experiments were performed in phosphate buffer solutions at pH = 7.4, with an incubation time of 10 min. The response of the sensor was a linear function of CPF concentration from 10− 10 to 10− 7 M with a corresponding equation: y = 0.1467x + 1.4472 (R2 = 0.9959) and a detection limit of 1.58 × 10− 10 M. The biosensor methodology was used to analyze CPF directly in broccoli that had been previously spiked with CPF solution.

The new modular walking robots MERO by reconfiguring their architecture are built to displace the heavy loads on the unaligned terrain. The main characteristic of the modular walking robots is that they are able to move away on unarranged, horizontal and rough terrain The modular walking system protects much better the environment when its contact with the soil is discrete, a fact that limits appreciately the area that is crushed. The new modular walking robots may have a lower or higher autonomy degree. This autonomy has in view the power source's supply capability but also orientation and perception capabilities as regards the terrain configuration the robot is running upon and its decision making and the motion manner towards a target. Architecture of the reference structure of the walking robot has three two-legged modules. Every leg has three degrees of freedom (RRP), a slip sensor and tactile sensor to measure the contact which consists of lower and upper levels. The body of the MERO (MEchanism RObot) walking robot carries a gyroscopic bearing sensor to measure the pitch and roll angles of the platform. The legs are powered by hydraulic drives and are equipped with transducers and sensors. They are used to control the walking robot in the adaptability to a natural ground. In this paper presents some aspects of the new modular walking robot

Potential difference measurements have been used to obtain the mean ionic activity and osmotic coefficients of NaCl and Na2SO4 in their aqueous solutions. Also, the mean ionic activity coefficients of NaCl in NaCl–Na2SO4–H2O ternary system with sodium as a common ion have been determined from cell potential measurements using: Na-ISE/NaCl (mNaCl); Na2SO4 (mNa2SO4)/Ag/AgCl combined with the reference cell: Na-ISE/NaCl (I = mNaCl + 3mNa2SO4), AgCl(s)/Ag. The measurements were made at ionic strength ratios for Na2SO4, yNa2SO4, of (0.0, 0.2, 0.4, 0.6, 0.8, and 1.0), at constant total ionic strengths, I, of (0.1, 0.5, 1.0, 2.0, 3.0, and 4.0) mol·kg–1 and at temperatures of (298.15, 303.15, and 308.15) K. The experimental mean ionic activity coefficients of NaCl were correlated and analyzed with the Harned rule and Scatchard and Pitzer models. The excess free Gibbs energies of mixing were calculated from the trace activity coefficient data of NaCl and analyzed versus system composition at different temperatures...

In this study we report first data on exfoliated graphitic nanoplatelets (xGnPs) as a sorbent for phenol removal and preliminary evaluated the ability of different type of natural organic matter (NOM) to effectively disperse exfoliated graphitic nanoplatelets.

A Pb2+-selective sensor was fabricated from polyvinyl chloride (PVC) matrix membranes containing the ionophore 3,7,11-tris (2-pyridylmethyl)-3,7,11,17-tetraazabicyclo [11.3.1] heptadeca-1(17),13,15-triene (I). The effects of anion excluders (KTpClPB, NaTPB) and plasticizers (o-NPOE, DBP, DOP) on the performance of the membrane sensor were studied. The membrane with the composition of I:PVC:o-NPOE:KTpClPB in the percentage ratio (wt.%) of 2:32:60:6 exhibited the best performance, having a slope of 28.5 ± 0.2 mV/decade in the concentration range 10− 6–10− 1 M, a response time of 20 s and a lifetime longer than four months. The sensor was selective for Pb2+ ions over other monovalent, divalent and trivalent interfering cations and could be used in the pH range of 5–8. The high selectivity in the presence of Cd2+ may be important for further studies. The efficiency of the proposed sensor was demonstrated by its application in Pb2+ ions determination in water samples.

Of all feasible designs, some are “better” than others. If this is assumed as true, then there must be some quality that the better designs have more of than the lees desirable ones do. This quality must be expressed as a computable function of the design variables, and it can consider optimizing to obtain a “best” design. The function with respect to which the design is optimized is called the objective function. In some design situations, there may appear to be two or more quantities which should be objective functions. The goal of the kinematics synthesis of the linkages is to establish the kinematics dimensions of the component elements provided that some conditions are imposed regarding movements of some points or elements. As a rule, only conditions about the positions of the points or elements are imposed. In the other words, only the transmission functions of the positions are used to write the synthesis equations. The solving of the kinematics synthesis problems is reduced to the solving of some nonlinear equation systems. As a result, the problems of the kinematics synthesis of linkages do not have the unique solutions. Only in some very simples particular cases the system of synthesis equations is linear and problem has a single solution. In the optimum synthesis of the gripper mechanisms, the objective function may express the positioning precision of the work pieces, the magnitude of the driving force, the domain of the stable fastening of the work pieces etc. In the work, some considerations about the optimum synthesis of the two fingered self centering grippers are shown.

The paper presents ZPM dynamic control of walking robots, developing an open architecture real time control multiprocessor system, in view of obtaining new capabilities for walking robots. The complexity of the movement mechanism of a walking robot was taken into account, being a repetitive tilting process with numerous instable movements and which can lead to its turnover on an uneven terrain. The control system architecture for the dynamic robot walking is presented in correlation with the control strategy which contains three main real time control loops: balance robot control using sensorial feedback, walking diagram control with periodic changes depending on the sensorial information during each walk cycle, predictable movement control based on a quick decision from the previous experimental data. The results obtained through simulation and experiments show an increase in mobility, stability in real conditions and obtaining of high performances related to the possibility of moving walking robots on terrains with a configuration as close as possible to real situations, respectively developing new technological capabilities of the walking robot control systems for slope movement and walking by overtaking or going around obstacles.

The strong dependence of heavy metal toxicity on metal physical–chemical structure has directed the interest in the qualitative and quantitative measurement of metal species in different environments. Mercury is ubiquitous in the environment, and occurs in three oxidation states in several physical and chemical forms. Among these, Hg(II) can severely damage the kidneys and the gastrointestinal tract, and is generally a serious hazard to human health. Potentiometric sensors based on ion-selective electrodes provide a simple, highly selective, precise, and economical method for online Hg(II) concentration monitoring in a variety of environments. Due to their selectivity, neutral carrier-based potentiometric sensors are routinely used for measuring ions directly in complex biological and environmental samples, and therein, several Hg(II)-selective electrodes have been studied in literature. This work presents a Hg(II) ion-selective electrode that uses a 1,4,8,11-tetrathiacyclotetradecane derivative entrapped inside a membrane for the measurement of Hg(II) in urine samples. Alumina modified dimethyl sulfoxide (AMDMSO) was used to separate Hg(II) from matrices, a mechanism already suggested in literature explaining the unique uptake of Hg(II) ions by binding as neutral at pH values

The present study was designed to investigate the toxic effects (evaluated as histopathological changes) of sodium fluoride on the kidney in two consecutive generations of NMRI mice. An attempt to correlate the toxicity with the urinary elimination of fluoride has been made, as urinary fluoride excretion has been widely used as an indicator of fluoride intake and exposure. Six mixed (males and females) animal groups have been constituted by dividing the populations of mice derived from pregnant females (named "mothers" 0.5 mg sodium fluoride) treated with 0.5 mg sodium fluoride by daily gavage and pregnant females (named "mothers" 0.25 mg sodium fluoride) treated with 0.25 mg sodium fluoride by daily gavage; three types of sodium fluoride treatments were administrated: homeopathic, allopathic-homeopathic and allopathic. When the animals reached the adulthood, by randomization, they were selected in pairs for giving birth to the second generation of mice. No treatments were administrated to the second generation of mice; thus, the urinary elimination of fluoride in the second generation is attributed to exposure at sodium fluoride before birth. The administration of sodium fluoride to the first generation (F1) is realized until the mice reached the adulthood. For the first generation, the urine was collected at three times, every three weeks: at the age of four weeks, seven weeks and 11 weeks; single sampling urine, at the age of four weeks, has been conducted for the second generation. The urine samples have been analyzed using the ion selective electrode method for fluoride. For the histopathological examination, the animals were killed by cervical dislocation; the kidneys were collected in a 10% formalin solution. The preparation of samples for optical microscopy was realized with Hematoxylin-Eosin staining. The results indicate that the elimination of fluoride was similar (at the second evaluation, at 7-week-old of the first generation) for the both generations of mice. Histopathological observation of the kidney has revealed granular dystrophy of the renal tubules, necrosis of the endothelial cells and of the mesangial cells of renal glomerulus. The study indicates that different sodium fluoride treatments produce some pathological aspects of the kidneys and influence the urinary elimination of fluoride in two consecutive generations of mice. For the higher doses, the pathological changes of the kidney are more important, and the urinary elimination of fluoride is higher, especially for the allopathic doses.

Voltammetric and UV spectrophotometric investigations of alkali and alkaline earth metal cations binding by the new ferrocene macrocyclic ligands 1–4 have been performed in acetonitrile electrolyte. Stability constants were determined from UV measurements. All the metal cations surveyed formed 1:1 stoichiometric complexes with 2 and 3 , with the exception of barium which produced a 1:2 intermolecular sandwich complex with 2 . No complexation occurred with 1 . Electrochemical studies have demonstrated that the binding of Li + , Na + , K + , Mg 2+ , Ca 2+ and Ba 2+ with 2 resulted in shifts of the ferrocene oxidation wave to more positive potentials. The same features were observed with 3 in the presence of Li + , Na + , K + and Mg 2+ , and with 4 and Ba 2+ . In contrast, a different type (two-wave behaviour) of positive shift revealed the binding of Ca 2+ and Ba 2+ with 3 , allowing the amperometric titration of these metal cations. The magnitude and the type of potential shift could not be related to the radius and charge to radius ratio of the cations, or to the strength of the host-guest association. It can be assumed that additional effects such as an effective charge transfer interaction between the cationic guest and the redox centre control the electrochemical recognition behaviour of these redox ionophores. Single crystal X-ray structure of [ 3 -Ba](ClO 4 ) 2 has also been determined to gain better understanding of the barium complextion in 3 .

The detection of organophosphoric insecticides, in a simple manner was made using impedimetric enzyme biosensors, which allow determination in sub-micromolar concentration ranges. This type of measurement applies for monitoring of biocatalytic reactions based on irreversible inhibition of the enzyme (acetylcholinesterase). The reaction involves generation of charged species, which leads to a global change in the ionic composition of the tested solution.Our work has been focused on the development of an impedimetric microsensor for direct detection of dichorvos, because this kind of biosensor presents a number of advantages such as: miniaturized electrodes based on gold thin film; easy production using standard microtechnology; low cost; no reference electrode required; no light sensitivity and differential mode measurements possibile allowing elimination of interferences. In addition, dichlorvos is targeted to be detected considering that the commonest poisoning today is due to: Methyl Parathion (metacid), Dichorvos (Nuvan), Zinc Phosphide and Aluminium Phosphide (Celphos). The biosensor with interdigitated electrodes and immobilized acetylcholinesteraze (AChE) measures the impedance of the layer adjacent to the electrode surface. The impedimetric measurement consists of determining the conductivity and capacitance of the solution between two interdigitated electrodes. The chemistry of deposited enzymatic layer (concentration, enzymatic activity measuring, deposition protocol), the immobilization technique for AChE, the fabrication technique and the electrical characteristiques of the enzymatic sensor have been studied. AChE immobilization was performed by ionic adsorption on polyethylenglycol (PEG) bio-polymeric substrate, by including in the gel. The functionalized electrodes deposited with biomaterial were inserted into the microfluidic channels and tested from electrical andmicrofluidic point of view, achieving the micro-bio integration. Insertion of electrolyte plus acetilcholine into the channels leads to activation of the enzyme and the measurements are realized under the strict control of temperature and pH. The response time is about 10 minutes.