This paper presents the comparative evaluation of multiple compact and lightweight 2D laser scanners for their possible backpack based scanning and mapping applications. These scanners include Hokuyo ...URG-04LX, Slamtec RPLidar A1-M8 and Hokuyo UTM-30LX-EW scanners. Since the technical datasheets provide general information and limited working details, this research presents a thorough study on the performance of each scanner related explicitly to indoor mapping operations. A series of scanning experiments have been performed for the characterization of each scanner using statistical analysis. During the testing, all the scanning data has been recorded using Robot Operating System (ROS) and then computed in offline processing. In initial tests, each scanner’s drift effect on range measurements has been tested and presented in the relevant section of the paper. In continuation, the effect of various scanning distances on measurement accuracy has been evaluated and discussed. Later the impact of various materials typically found in indoor vicinities and their respective properties of color and smoothness have been tested and provided in the paper. Finally, a Kalman Filtering based mathematical formulation has been utilized to calibrate each scanner and to reduce the measuring uncertainties as observed in various tests for each scanner.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The electrical characterization of p-Silicon (Si) and n-Zinc oxide (ZnO) nanorod heterojunction diode has been performed. ZnO nanorods were grown on p-Silicon substrate by the aqueous chemical growth ...(ACG) method. The SEM image revealed high density, vertically aligned hexagonal ZnO nanorods with an average height of about 1.2 μm. Electrical characterization of n-ZnO nanorods/p-Si heterojunction diode was done by current-voltage (I-V), capacitance-voltage (C-V), and conductance-voltage (G-V) measurements at room temperature. The heterojunction exhibited good electrical characteristics with diode-like rectifying behaviour with an ideality factor of 2.7, rectification factor of 52, and barrier height of 0.7 V. Energy band (EB) structure has been studied to investigate the factors responsible for small rectification factor. In order to investigate nonidealities, series resistance and distribution of interface state density (NSS) below the conduction band (CB) were extracted with the help of I-V and C-V and G-V measurements. The series resistances were found to be 0.70, 0.73, and 0.75 KΩ, and density distribution interface states from 8.38 × 1012 to 5.83 × 1011 eV−1 cm−2 were obtained from 0.01 eV to 0.55 eV below the conduction band.
Dye-sensitized solar cells (DSSCs) are made of manganese dioxide (MnO2) and Ag-doped manganese dioxide (Ag-MnO2) counter electrodes (CEs). Herein, MnO2 and Ag-MnO2 were synthesized using the ...hydrothermal method and deposited through the drop casting technique. Electrical characterizations were performed to obtain the fill factor (FF), short-circuit current density (JSC), open-circuit voltage (VOC), and power conversion efficiency (PCE). Frequency- and voltage-dependent impedance spectroscopy were performed to gain an insight into the charge transport characteristics. DSSCs fabricated with a MnO2-coated electrode gave a PCE of 2.86% with a VOC of 0.60 V and a JSC of 8.72 mA/cm2, while DSSCs fabricated with Ag-MnO2 CEs demonstrated a higher PCE of 3.05%, with a VOC of 0.66 v and a JSC of 13.3 mA/cm2. The obtained results indicate that Ag-doped MnO2-coated counter electrodes have the potential to replace expensive Pt=coated counter electrodes.
The aim of this study is to boost the power conversion efficiency of a dye-sensitized solar cell (DSSC) by using the co-sensitization strategy with appropriate natural dyes extracted from ...pomegranate, beetroot and cranberry. The fabricated DSSCs were evaluated using current–voltage characteristics and UV-Vis spectroscopy. The co-sensitized DSSC with beetroot and cranberry showed higher short-circuit current density and power conversion efficiency than their individual dye-based DSSCs. This improvement in the performance is due to the lower aggregation of the dyes, broader absorption in the visible region and lower value of impedance. However, co-sensitized DSSCs of pomegranate with beetroot and cranberry did not show any improvement in performance.
The effect of post-growth annealing treatment of zinc oxide (ZnO) nanorods on the electrical properties of their heterojunction diodes (HJDs) is investigated. ZnO nanorods are synthesized by the ...low-temperature aqueous solution growth technique and annealed at temperatures of 400 and 600°C. The as-grown and annealed nanorods are studied by scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. Electrical characterization of the ZnO/Si heterojunction diode is done by current–voltage (
) and capacitance–voltage (
) measurements at room temperature. The barrier height (
), ideality factor (
), doping concentration and density of interface states (
) are extracted. All HJDs exhibited a nonlinear behavior with rectification factors of 23, 1,596 and 309 at ±5 V for the as-grown, 400 and 600°C-annealed nanorod HJDs, respectively. Barrier heights of 0.81 and 0.63 V are obtained for HJDs of 400 and 600°C-annealed nanorods, respectively. The energy distribution of the interface state density has been investigated and found to be in the range 0.70 × 10
to 1.05 × 10
eV/cm
below the conduction band from
= 0.03 to
= 0.58 eV. The highest density of interface states is observed in HJDs of 600°C-annealed nanorods. Overall improved behavior is observed for the heterojunctions diodes of 400°C-annealed ZnO nanorods.
This paper presents a method to generate a Georeferenced 3D point cloud of GPS denied built structures using custom made backpack laser scanning system. An orthogonal combination of 2D Hokuyo laser ...scanners has been used on the backpack system to generate a 3D point cloud of the surveyed environments. The data logging of scanners and simultaneous localization and mapping (SLAM) of the scanning system have been carried out using Robot Operating System (ROS). The developed local SLAM based 3D point cloud solution has been transformed into global Georeferenced 3D point cloud using observed geographic coordinates of nearby GPS visible vicinities. Multiple indoor environments have been scanned and 3D point clouds have been developed which have been found accurate when compared to the ground truth. In comparison to available surveying solutions present in the local market, the developed system has been found more accurate, faster, and user friendly to generate structural results of the surveyed vicinities in detail. The efficacy of the system has been witnessed by local surveying companies by delivering the unique global coordinated solutions on affordable rates.
The effect of thermal annealing atmosphere on the electrical characteristics of Zinc oxide (ZnO) nanorods/p-Silicon (Si) diodes is investigated. ZnO nanorods are grown by low-temperature aqueous ...solution growth method and annealed in Nitrogen and Oxygen atmosphere. As-grown and annealed nanorods are studied by scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. Electrical characteristics of ZnO/Si heterojunction diodes are studied by current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. Improvements in rectifying behaviour, ideality factor, carrier concentration, and series resistance are observed after annealing. The ideality factor of 4.4 for as-grown improved to 3.8 and for Nitrogen and Oxygen annealed improved to 3.5 nanorods diodes. The series resistances decreased from 1.6 to 1.8 times after annealing. An overall improved behaviour is observed for oxygen annealed heterojunction diodes. The study suggests that by controlling the ZnO nanorods annealing temperatures and atmospheres the electronic and optoelectronic properties of ZnO devices can be improved.
Improvement in panchromatic light-harvesting and photovoltaic performance is reported for dye-sensitized solar cells by adopting co-sensitization technique by mixing dyes. Betalain and Anthocyanin ...natural dyes are extracted from beetroot and cranberries. All dyes are characterized by UV–Vis and FTIR spectroscopy. Solar cells are fabricated and electrical characterizations are performed. Solar cell sensitized with mixed dyes demonstrated improved performance compared to cells of individual dyes, and yielded short circuit current density, open circuit voltage and fill factor of 0.36 mA/cm2, 0.42 V and 0.51 respectively. Their maximum efficiency is 5.37 and 1.16 times higher than that of individual beetroot and cranberry dye DSSCs respectively. Charge transfer processes are studied by impedance spectroscopy characterizations. The obtained results are in close agreement with commercially available N3 dye DSSC. The results yield that mixing dyes from different natural sources can be a very effective to further improve the performance of DSSCs.
Zinc sulfide nanoparticles are embedded in unsaturated polyester resins (UPR) to form nanocomposites through the hand layup method. It is observed that dielectric, magnetic and mechanical properties ...improved due to strong interaction between ZnS nanofillers and UPR matrix. The amorphous nature of prepared nanocomposites confirmed by x-ray diffraction. SEM images revealed that UPR based nanocomposites exhibited well dispersion of ZnS nanoparticles. ZnS nanofillers (2.5 wt % concentration) exhibited significant/improved values of dielectric constant 309, ac conductivity 2.71 × 10−4S/cm, coercivity 259Oe, magnetic saturation 0.117 emu/g, and magnetic remanence 2.9 × 10−3emu/g. Whereas, good tensile strength 6.56 MPa and Young's modulus 99.7 MPa is observed at 2 wt % concentration of ZnS nanofillers. This work suggests that the prepared semiconducting ZnS nanofillers in the UPR matrix has potential as an electro-magnetic material with remarkable properties.
Photoelectrical characterization and impedance spectroscopy are performed for Dye sensitized solar cells (DSSC) fabricated by using natural dye (Pomegranate extract) and metallic dye (N719). Dyes are ...characterized by ultraviolet–visible spectroscopy to study optical properties. Typical photovoltaic behaviors are observed with open circuit voltage of 0.52 and 0.7 V and short circuit current density of 0.34 and 14 mA/cm2 for natural and metallic dyes based cells respectively. From current–voltage (I-V) measurements, fill factor, conversion efficiency and ideality factor are extracted. Electrical properties of the cells are investigated using Mott-Schottky plots. To gain insight into charge transport, voltage and frequency dependent impedance spectroscopy is performed. Photovoltaic performance of cells is evaluated from the trends of recombination resistance and chemical capacitance in the measured impedance spectra. Significant contribution of interface trap states is observed at low frequencies and reversal of the polarity of capacitance from positive to negative values is observed at higher frequencies. The overall behavior of devices is compared. To our knowledge these impedance spectroscopy results for natural dye based solar cell are not reported earlier. Their insight and understanding is important for optimizing various components and interfaces for the development of cost effective commercially available natural dyes based DSSCs.
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