Emulation of the Space Robotics System on Earth

Present and future, without the sophisticated and highly automated mechanisms, it is impossible to fulfil the humanity's destiny in space. Thus to determine the success of ambitious space missions of the future, the humans and space robots have to form an excellent integrated team. Generally space robotic systems are designed, developed and operated to assist or replace humans in accomplishing tasks that are dangerous, costly or simply impossible for humans. The nature and operation of space systems are totally different from on earth such as zero gravity environments, have made the modifications of design and usage of robotics in space very important. This research comprises an analytical and experimental study of space robot locomotion. The main objective of this research work is to build a test-bed for space robot emulation that operates in the "zero gravity" situation. To experimentally study the locomotion of space robot in the laboratory, one has to create a "zero gravity" or "less gravity" environment. In order to perform simulations of partial or micro gravity environments on earth requires some method of compensation for the earth's gravitational field. To achieve this, gravity-less 2 Degrees-Of-Freedom robot with an unique instrumental arrangement was considered to compensate the gravity force. The space robot kinematics and dynamics formulations are studied, especially the Denavit-Hartenberg CD-H) parameters and Newton-Euler formulation. The feedbacks of the robot's arms are detected by encoders at the servomotors and transducers around the robot and sent to the computer through PC interface card. The space robot dynamic algorithms were tested in simulation and as well as in practical. The data especially the torque values, the joint positions and angular velocities of the robot's arm in the "zero gravity" environment as well as with gravitational effect were taken from the experimental and simulation. The simulation comprises the combination of mechanical simulation and virtual prototyping software, Mechanical Desktop and MSC Working Model. The graphs were plotted from data by using Excel. The Mathematical software package, Mathematica is used to derive the equations of motion. Finally all the trend graphs were plotted using Excel. The results were compared and analyzed with derived equations to prove that the "zero gravity" condition is achieved. Moreover this instrumental setup for emulation of space robot system can be used for various algorithms study based on robotics, control and other areas

Subminiature panel (SMA-P) coaxial sensor for the determination of moisture content of mango cv. Chok Anan

The research describes the development of a simple, cheap and efficient open-ended coaxial sensor for the determination of moisture content of Chok Anan mango during fruit ripening from week 5 to week 17. The sensor was a modification of a standard subminiature panel (SMA-P). The finite element method was used to calculate the numerical values of the reflection coefficient. The reflection coefficient of the sensor was measured using a Microwave Network Analyzer in the frequency range from 1 to 4 GHz. The actual moisture content was obtained using standard oven drying method. A calibration equation was obtained to predict moisture content from the measured reflection coefficient at 1 GHz with accuracy within 1.5%. The results indicate that the amount of m.c. in Chok Anan mango can be determined with excellent accuracy using a SMA-P coaxial sensor as an OEC sensor

Highly sensitive Escherichia coli shear horizontal surface acoustic wave biosensor with silicon dioxide nanostructures

Surface acoustic wave mediated transductions have been widely used in the sensors and actuators applications. In this study, a shear horizontal surface acoustic wave (SHSAW) was used for the detection of food pathogenic Escherichia coli O157:H7 (E.coli O157:H7), a dangerous strain among 225 E. coli unique serotypes. A few cells of this bacterium are able to cause young children to be most vulnerable to serious complications. Presence of higher than 1 cfu E.coli O157:H7 in 25 g of food has been considered as a dangerous level. The SHSAW biosensor was fabricated on 64° YX LiNbO3 substrate. Its sensitivity was enhanced by depositing 130 nm thin layer of SiO2 nanostructures with particle size lesser than 70 nm. The nanostructures act both as a waveguide as well as a physical surface modification of the sensor prior to biomolecular immobilization. A specific DNA sequence from E. coli O157:H7 having 22 mers as an amine-terminated probe ssDNA was immobilized on the thin film sensing area through chemical functionalization [(CHO-(CH2)3-CHO) and APTES; NH2-(CH2)3-Si(OC2H5)3]. The high-performance of sensor was shown with the specific oligonucleotide tar- get and attained the sensitivity of 0.6439 nM/0.1 kHz and detection limit was down to 1.8 femto-molar (1.8×10−15 M). Further evidence was provided by specificity analysis using single mismatched and complementary oligonucleotide sequences

Fabrication of Cu2O Nanostructured Thin Film by Anodizing

Cuprous oxide, a narrow bandgap p-type semiconductor, has been known as a potential material for applications in supercapacitors, hydrogen production, sensors, and energy conversion due to its properties such as non-toxicity, easy availability, cost effectiveness, high absorption coefficient in the visible region and large minority carriers diffusion length. In this study, Cu2O nanostructured thin film was fabricated by anodizing of Cu plates in ethylene glycol containing 0.15 M KOH, 0.1 M NH4F and 3 wt.% deionized water. The effects of anodizing voltage and temperature of electrolyte were investigated and reported. It was found that nanoporous Cu2O thin film was formed when anodizing voltages of 50 V and 70 V were used while a dense Cu2O thin film was formed due to the aggregation of smaller nanoparticles when 30 V anodizing voltage was used. Nanoplatelets thin film was formed when the temperature of electrolyte was reduced to 15 °C and 5 °C. X-ray diffraction confirmed the presence of Cu2O phase in thin film formed during anodizing of Cu plates, regardless of the anodizing voltage and temperature of electrolyte. Photoluminescence spectroscopy showed the presence of Cu2O peak at 630 nm corresponding to band gap of 1.97 eV. A mechanism of the formation of Cu2O thin film was proposed. This study reported the ease of tailoring Cu2O nanostructures of different morphologies using anodizing that may help widen the applications of this material