ALBERT

Description: Investigation of the effect of thermal radiation on a fully developed magnetohydrodynamic (MHD) convective flow of a Newtonian, incompressible and electrically conducting fluid in a vertical microchannel bounded by two infinite vertical parallel plates with constant temperature walls through a lateral magnetic field of uniform strength is presented. The Rosseland model for the conduction radiation heat transfer in an absorbing medium and two plates with slip-flow and no-slip conditions are assumed. In addition, the induced magnetic field is neglected due to the assumption of a small magnetic Reynolds number. The non-dimensional governing equations are solved numerically using Runge–Kutta–Fehlberg method with a shooting technique. The channel is optimized based on the Second Law of Thermodynamics by changing various parameters such as the thermal radiation parameter, the temperature parameter, Hartmann number, Grashof to Reynolds ratio, velocity slip length, and temperature jump.

Description: The aim of this study was to confirm the effects of two-stage combustion on the combustion and NOx reduction characteristics of a four cylinder direct injection diesel engine. In order to analyze the combustion and emission characteristics, various injection parameters, such as injection quantity, injection timing and injection pressure were used under constant engine speed and engine load. In addition, the experimental results of two-stage combustion are compared to the single injection when injection timing is 5° BTDC. The experimental results showed that NOx emissions were significantly reduced when applying two-stage combustion. In particular, an injection strategy when the first and second injections have a same quantity, the results showed the maximum reduction of NOx emissions in this experiment. The NOx emissions were also reduced when the timing of the first injection was advanced. However, NOx emissions indicated almost similar concentration regardless of first injection timings when the first injection timing was earlier than 50° BTDC. In the case of soot emissions were slightly increased compare to the single injection cases at tested conditions.

Description: The aim of this study was to confirm the effects of two-stage combustion on the combustion and NOx reduction characteristics of a four cylinder direct injection diesel engine. In order to analyze the combustion and emission characteristics, various injection parameters, such as injection quantity, injection timing and injection pressure were used under constant engine speed and engine load. In addition, the experimental results of two-stage combustion are compared to the single injection when injection timing is 5° BTDC. The experimental results showed that NOx emissions were significantly reduced when applying two-stage combustion. In particular, an injection strategy when the first and second injections have a same quantity, the results showed the maximum reduction of NOx emissions in this experiment. The NOx emissions were also reduced when the timing of the first injection was advanced. However, NOx emissions indicated almost similar concentration regardless of first injection timings when the first injection timing was earlier than 50° BTDC. In the case of soot emissions were slightly increased compare to the single injection cases at tested conditions.

Description: We have developed a simple electrochemical biosensing strategy for the label-free diagnosis of hepatitis B virus (HBV) on a gold electrode surface. Gold-binding polypeptide (GBP) fused with single-chain antibody (ScFv) against HBV surface antigen (HBsAg), in forms of genetically engineered protein, was utilized. This GBP-ScFv fusion protein can directly bind onto the gold substrate with the strong binding affinity between the GBP and the gold surface, while the recognition site orients toward the sample for target binding at the same time. Furthermore, this one-step immobilization strategy greatly simplifies a fabrication process without any chemical modification as well as maintaining activity of biological recognition elements. This system allows specific immobilization of proteins and sensitive detection of targets, which were verified by surface plasmon resonance analysis and successfully applied to electrochemical cyclic voltammetry and impedance spectroscopy upto 0.14 ng/mL HBsAg.

Description: Sensors, Vol. 18, Pages 2392: Geometric Parameter Calibration for a Cable-Driven Parallel Robot Based on a Single One-Dimensional Laser Distance Sensor Measurement and Experimental Modeling Sensors doi: 10.3390/s18072392 Authors: XueJun Jin Jinwoo Jung Seong Young Ko Eunpyo Choi Jong-Oh Park Chang-Sei Kim A cable-driven parallel robot has benefits of wide workspace, high payload, and high dynamic response owing to its light cable actuator utilization. For wide workspace applications, in particular, the body frame becomes large to cover the wide workspace that causes robot kinematic errors resulting from geometric uncertainty. However, appropriate sensors as well as inexpensive and easy calibration methods to measure the actual robot kinematic parameters are not currently available. Hence, we present a calibration sensor device and an auto-calibration methodology for the over-constrained cable-driven parallel robots using one-dimension laser distance sensors attached to the robot end-effector, to overcome the robot geometric uncertainty and to implement precise robot control. A novel calibration workflow with five phases—preparation, modeling, measuring, identification, and adjustment—is proposed. The proposed calibration algorithms cover the cable-driven parallel robot kinematics, as well as uncertainty modeling such as cable elongation and pulley kinematics. We performed extensive simulations and experiments to verify the performance of the suggested method using the MINI cable robot. The experimental results show that the kinematic parameters can be identified correctly with 0.92 mm accuracy, and the robot position control accuracy is increased by 58%. Finally, we verified that the developed calibration sensor devices and the calibration methodology are applicable to the massive-size cable-driven parallel robot system.

Description: Sensors, Vol. 17, Pages 2016: Analysis of Multi-Level Simultaneous Driving Technique for Capacitive Touch Sensors Sensors doi: 10.3390/s17092016 Authors: Jong Park Chang-Ju Lee Jong Kim The signal-to-noise ratio (SNR) and driving levels of capacitive touch sensors determine the applicability of these sensors to thinner displays and sensor-integrated modules. The simultaneous driving technique has been widely applied to capacitive touch sensors to cope with various types of environmental noise. A Hadamard matrix has been used to determine the driving code and multiplex capacitive signals required to increase the SNR and responsivity of touch sensors. Using multi-level Hadamard matrices, a new driving technique for sensing concurrent capacitive elements across multiple rows of a touch panel was developed. The technique provides more effective design choices than the existing bipolar driving method by supporting a variety of orders of matrices and regular capacity. The required TX voltage can be reduced by applying the Kronecker product for higher orders of simultaneous driving. A system model is presented for multiplexing capacitive signals to extract the SNR of the existing Hadamard matrices as well as one of the proposed multi-level sequences. In addition, the corresponding multi-level drivers and receivers were implemented to verify the theoretical expectations and simulation results of the proposed technique.

Description: Sustainability, Vol. 9, Pages 1593: Does Social Media Use Influence Entrepreneurial Opportunity? A Review of its Moderating Role Sustainability doi: 10.3390/su9091593 Authors: Joo Park Chang Sung Il Im Social media platforms are an indispensable part of entrepreneurship practices. They offer entrepreneurs a platform for business growth and brand development. However, little is known about the effect of social media use on identifying entrepreneurial opportunities. Utilizing social cognition theory, this research focuses on how certain factors—prior knowledge, alertness, and social media—may impact two aspects of opportunity: the discovery and the creation of entrepreneurial opportunity. This study focuses on the investigation of the moderating role of social media use on entrepreneurial opportunities. The findings have important practical and academic implications for how social media impacts entrepreneurship and can be used to increase the ability of entrepreneurs to find new opportunities.

Description: Utilizing a simple fluidic structure, we demonstrate the improved performance of oxidase-based enzymatic biosensors. Electrolysis of water is utilized to generate bubbles to manipulate the oxygen microenvironment close to the biosensor in a fluidic channel. For the proper enzyme reactions to occur, a simple mechanical procedure of manipulating bubbles was developed to maximize the oxygen level while minimizing the pH change after electrolysis. The sensors show improved sensitivities based on the oxygen dependency of enzyme reaction. In addition, this oxygen-rich operation minimizes the ratio of electrochemical interference signal by ascorbic acid during sensor operation (i.e., amperometric detection of hydrogen peroxide). Although creatinine sensors have been used as the model system in this study, this method is applicable to many other biosensors that can use oxidase enzymes (e.g., glucose, alcohol, phenol, etc.) to implement a viable component for in-line fluidic sensor systems.

Description: Remote Sensing, Vol. 10, Pages 1261: Measurement of Planetary Boundary Layer Winds with Scanning Doppler Lidar Remote Sensing doi: 10.3390/rs10081261 Authors: Soojin Park Sang-Woo Kim Moon-Soo Park Chang-Keun Song The accurate measurement of wind profiles in the planetary boundary layer (PBL) is important not only for numerical weather prediction, but also for air quality modeling. Two wind retrieval methods using scanning Doppler light detection and ranging (lidar) measurements were compared and validated with simultaneous radiosonde soundings. A comparison with 17 radiosonde sounding profiles showed that the sine-fitting method was able to retrieve a larger number of data points, but the singular value decomposition method showed significantly smaller bias (0.57 m s−1) and root-mean-square error (1.75 m s−1) with radiosonde soundings. Increasing the averaging time interval of radial velocity for obtaining velocity azimuth display scans to 15 min resulted in better agreement with radiosonde soundings due to the signal averaging effect on noise. Simultaneous measurements from collocated wind Doppler lidar and aerosol Mie-scattering lidar revealed the temporal evolution of PBL winds and the vertical distribution of aerosols within the PBL.