Automation of a complex transfer operation using a polar manipulator

Purpose – The objective of this paper included developing a polar robot (SPBot) for rotating and transferring car engine block (CEB) around and along two different axes in a confined workspace envelope. Design/methodology/approach – The complex transfer operations of the CEB requires sweeping complete surface of the half sphere, and thus a polar robot is best suited to such a task in a confined space. Considering the limited space for this operation, a specially designed manipulator is built comprising 2 degrees of freedom driven by electrical servo motors. Also due to the special form of CEB, an especially designed pneumatic gripper is developed. Kinematics models, static and dynamic equations, together with trajectory planning for such a manipulator are described. Findings – The high-speed complex transfer in a limited environment is successfully implemented. Originality/value – The developed polar robot provides for complex transfer operations that significantly increases the speed of the product line and thus reducing the cycle time from 60?s using manpower to just 20?s using the robot

Kinematics analysis of 6-DOF parallel micro-manipulators with offset u-joints : a case study

This paper analyses the kinematics of a special 6-DOF parallel micro-manipulator with offset RR-joint configuration. Kinematics equations are derived and numerical methodologies to solve the inverse and forward kinematics are presented. The inverse and forward kinematics of such robots compared with those of 6-UCU parallel robots are more complicated due to the existence of offsets between joints of RR-pairs. The characteristics of RR-pairs used in this manipulator are investigated and kinematics constraints of these offset U-joints are mathematically explained in order to find the best initial guesses for the numerical solution. Both inverse and forward kinematics of the case study 6-DOF parallel micro-manipulator are modelled and computational analyses are performed to numerically verify accuracy and effectiveness of the proposed methodologies

Semiotic Approach to Globalization: Living in a World of Glocal Things

This paper is an effort to discuss the concept of glocalization from a semiotic point of view. In order to carry out a semiotic analysis of globalization or glocalization, first globalization needs to be defined from a semiotic perspective. Therefore, first an explanation of globalization and glocalization in semiotic terms is provided. Some believe the ongoing process in the world cannot be best described as globalization and it should be called glocalization. According to this approach, the ongoing universal process is a combination of globalization and localization leading to new diversities, not uniformity. With a structuralist approach to semiotics a better understanding is gained on how glocalization may affect the world in which we are living. After a theoretical argument on the semiotic definition of globalization and glocalization, the results of a number of in-depth interviews with people who have experienced living in two different cultures will be analyzed in a qualitative method to provide further insight on how glocalization might work

Design of a Variable Reactor for Load Balancing and Harmonics Elimination

This paper presents the design of a variable inductor with a rotational magnetic core whose position is controlled in a closed-loop system. This magnetic structure facilitates the impedance changes which may be used for load balancing, harmonics elimination, transient response improvement, and as a controlled reactor in static VAr compensation (SVC). The design of the inductor and analysis of its impedance change caused by positioning a movable element are carried out by using the finite element method. As a result, the variation range of the impedance is determined. The proposed variable inductor is compared with a typical SVC reactor. The results show good performances in static var compensation with higher reliability and no harmonics generated. For closed-loop control, a secondorder sliding mode controller is designed for position control of the rotating core via a DC motor. Simulation results of the proposed system present highly robust and accurate responses without control chattering in face of nonlinearities and disturbances

Design of second-order sliding mode controllers for MR damper-embedded smart structures

This paper presents the design of second-order sliding mode controllers for semi-active control using magneto-rheological (MR) dampers. The approach can be useful in applications involving shock absorbers but here our main concern is the suppression of building vibrations induced by dynamic loadings such as earthquakes or strong winds. The MR dampers have been of increasing interest in structural control as they are inexpensive to manufacture and have attractive properties such as small energy requirements, reliability and stability in operations, as well as a fast response of milliseconds. Challenges of MR damper structural control rest with the system's high nonlinearity due to the force-velocity hysteresis, and the constraint of the magnetisation current, required to be between its zero and maximal values. A variety of control algorithms have been applied, including the decentralized bangbang control, modulated homogeneous friction algorithm, clipped optimal control, Lyapunov-based control, and also non model-based intelligent schemes. In these techniques, the currents are usually obtained from the damping force indirectly rather than directly from the controller output. For direct current control, in this paper we propose second-order sliding mode controllers, which can satisfy the control constraint, provide high accuracy, retain robustness and remove chattering. The effectiveness of the proposed direct current control technique is verified, in simulations, on a benchmark building model subject to excitation of various scaled earthquake records

Ojačanje spojeva između LVL elemenata polimerima ojačanim staklenim vlaknima i analiza metodom konačnih elemenata

The goal of this study was to investigate the effect of glass fiber reinforced polymer (GFRP) on joints made of laminated veneer lumber (LVL), through experimental data and evaluation by ANSYS finite element (FE) software. In order to fabricate LVL, veneer from poplar (Populus deltoides Bartr. ex Marsh) with 2.5 mm thickness and PVA adhesive were used. T-shape joints out of LVL were made and two wooden dowels were incorporated as well. Then GFRP was applied to reinforce the joints. GFRP in three grammages (100, 200 and 300 g/ m2) was adhered to joints with epoxy resin. Joints reinforcement was performed by a two-layer reinforcing agent. For comparing the effectiveness, half of the specimens were reinforced on sides and the other half on edges. Specimens were tested in static bending. The results have shown that GFRP had a significant effect on the strength of joints. Reinforced joints on both sides were stronger than those reinforced on edge. Joints reinforced with 300 g/m2 GFRP were improved by 35 % and 43 %, respectively, compared to 100 and 200 g/m2 grammage. Failure modes of specimens are dependent on GFRP grammage. The results of FE have shown that the highest concentration of stress and elastic strain was generated in the tension and compression zones of joints.Cilj rada bio je na temelju eksperimentalnih podataka i analize konačnih elemenata (FE) te uz pomoć softvera ANSYS istražiti utjecaj polimera ojačanog staklenim vlaknima (GFRP) na spojeve od lamelirane drvne građe (LVL). Za izradu LVL-a upotrijebljen je furnir drva topole (Populus deltoides Bartr. ex Marsh) debljine 2,5 mm i PVA ljepilo. Izrađeni su T-spojevi od LVL-a i ugrađena su dva drvena moždanika. Zatim je za ojačanje spojeva primijenjen GFRP u tri gramature (100, 200 i 300 g/m2) tako da je epoksidnom smolom zalijepljen na spojeve. Ojačanje spojeva izvedeno je dvoslojnim armaturnim sredstvom. Radi usporedbe učinkovitosti, polovica uzoraka ojačana je sa strane, a druga polovica na rubovima. Uzorci su ispitani na statičko savijanje. Rezultati su pokazali da GFRP ima značajan utjecaj na čvrstoću spojeva. Spojevi ojačani s obje strane bili su jači od onih ojačanih na rubu. Spojevi ojačani GFRP-om od 300 g/m2 poboljšani su za 35 % odnosno za 43 % u usporedbi s GFRP-om gramature100 i 200 g/m2. Načini loma uzoraka ovisili su o gramaturi GFRP-a. Rezultati analize konačnih elemenata pokazali su da se najveća koncentracija naprezanja i elastične deformacije pojavljuje u vlačnoj i tlačnoj zoni spojeva

Identification of exoS, exoU genes in Pseudomonas aeruginosa

The bacterium Pseudomonas aeruginosa is a common cause of infections, and infection with antibiotic-resistant strains can be dangerous. The aim of the present study is to investigate the presence of the exoS and exoU genes and the formation of biofilms in clinically isolated P.aeruginosa strains. A total of 126 samples were isolated, and P.aeruginosa was identified using biochemical tests. Bacterial genomic DNA was extracted, and the presence of the exoS and exoU genes were detected by PCR. Biofilms were formed by culturing P.aeruginosaon glass slides in rich medium. The exoU (76%) exoS (68%) genes were detected in of strains isolated from burn (burns caused by heat) patients, respectively. Among the 113 strains isolated from patients with burn infections. An improved understanding of virulence genes and biofilm formation in P.aeruginosa may facilitate the future development of novel vaccines and drug treatments.

Zinc Oxide Nanostructures Grown Using Electric Field-Assisted Aqueous Solution Method For Uv Photodetector Applications

Nanostructured zinc oxide (ZnO) was successfully synthesized using an electric field-assisted aqueous solution (EFAS) technique. ZnO nanostructures were grown with different growth parameters and characterized for the structural, optical and electrical properties. The study employed ZnO-seeded porous silicon (PSi) to grow one-dimensional (1-D) ZnO nanostructures. ZnO nanorod arrays were synthesized via the optimization of current density by using EFAS method and the ZnO nanorods were grown on PSi substrates that were prepared via a photo electrochemical etching (PECE) technique. Vertically aligned needle-shaped ZnO sample prepared at a current density of 0.5 mA/cm2, growth temperature of 105 °C, precursor concentration of 50 mM, and growth duration of 60 minutes produced the optimal structural, morphological, and optical properties with the highest (002) XRD peak intensity. Moreover, photoluminescence (PL) data of the optimized sample revealed the highest near-band-edge emission to deep-level emission intensity ratio while Raman data showed the most intense E2 (high) phonon mode compared with that of other samples. Using the optimized precursor concentration in the EFAS method, 1-D ZnO nanostructure arrays were grown on PSi subtrates. 1-D ZnO nanorods with cone heads were produced using the EFAS technique when the growth parameters were tuned at 50 mM precursor concentration, 0.65 mA/cm2 current density, 105 °C growth temperature and 60 minutes growth duration