Walailak Journal of Science and Technology (WJST)

Facile Synthesis of Spherical Flake-shaped CuO Nanostructure and Its Characterization towards Solar Cell Application

Jemibha PAULDURAI — 2021-08-29

The aim of this work is to synthesis CuO nanoparticles and investigates their eminent properties to identify their diverse application capability in the field of solar cells. In this work, CuO nanoparticles were synthesized by precipitation method using Copper (II) nitrate and Copper (II) chloride. Surface effects due to defects, structural properties related through lattice parameter, and crystallite sizes of nanoparticles have been identified from XRD. The crystal plane and reflection peak position was calculated using Bragg’s law. It showed that CuO nanoparticles have a monoclinic structure, and that the average crystallite size of CuO nanoparticles was 28.82 nm. n-type semiconductor behavior had a direct band of E_g = 1.465(2) eV, analyzed from optical studies by DRS. The band gap of the sample was determined from the reflectance spectra using Kubelka-Munk (K-M) function. Elements present were found through absorption peak of FTIR. The blue shifts observed in FTIR spectra in CuO nanoparticles were compared with that of bulk CuO, and absorption band agreed with XRD results. Morphological studies revealed the formation of spherical flake-shaped formation of CuO. It had a higher surface area and was well-suited to solar cell applications.

HIGHLIGHTS

The CuO nanoparticles were synthesized by precipitation method
The average crystallite size of CuO nanoparticles obtained in the range of 28.82 nm
Spherical flake-shaped nanostruture with higher surface area formed in this method
Optical property of CuO (E_g = 1.465 eV) and good electron mobility make it a suitable solar cell absorber material

GRAPHICAL ABSTRACT

Germination, Morphological and Physiological Evaluation of Seedlings Pretreated with Colchicine in Soybean (Glycine max L)

Phetole MANGENA — 2021-08-29

Wider genetic diversity has the potential to improve crop productivity of soybean, especially under environmental stress conditions. The pre-treatment of soybean seeds with antimitotic agents to establish improved genetic pool may also contribute to the enhancement of germination, seedling development, morpho-physiological growth and yield. In this study, 2 soybean genotypes viz. TGx1835-10E and Dundee were imbibed in solutions containing different amounts of colchicine (0.0, 0.1, 0.5 and 1 %) to evaluate the variations in germination, morphometric and physiological parameters. The seeds were imbibed for the period of 12 and 24 h before sowing for germination in plastic pots containing moistened sterile vermiculite. The variance components expressed as means, and mean percentage of total variations showed that colchicine concentration and imbibitional duration were the most important sources of variation for all traits, followed by the genotypes. Significant responses were detected for various germination parameters, seedling morphology and physiological contents such as; chlorophyll content, total phenolics, flavonoids as well as total protein and DNA content in the 2 genotypes used.

HIGHLIGHTS

Mutagenic pre-treatment of seeds via imbibition
Germination and seedling growths of colchicine preconditioned seeds
Chloroplastidic pigment analysis of pre-treated seedlings
Physiological valuation of primary and secondary metabolites in grown seedlings
Role of colchicine on germination, seedling development and growth of soybean plantlets

GRAPHICAL ABSTRACT

The 2D Barcodes Identify the Workpieces by using Microcontroller Interface between Image Processing and PLC Machine

Napassadol SINGHATA — 2021-08-29

This paper focuses on 3 main subjects; the first is the presentation and implementation of a PLC concept as a core component to control the system in the industry. The next subject of this work involves some tests to detect 2D barcodes with a web camera on 5 similar workpieces. It is difficult to classify and detect 2D barcodes since they are small about a size of 0.5×0.5 cm² patterned squares. The last part of the paper presents the implementation of a technique by using a microcontroller to link between a vision system and PLC. This method can be used in an old type of PLC without an additional equipment in the PLC, which can be connected to various types of cameras. The results of the system test show that the vision system can operate in the automatic classifying machine of the PLC controller. The machine vision can classify similar workpieces by using small 2D barcodes with image processing methods. The workpieces are stored in the correct position of 5 boxes in the storage compartment. This method of using a microcontroller interface with image processing and the PLC was successful.

HIGHLIGHTS

Web camera sensor read 2D barcodes
Decoding 2D barcode and transform to digital signal
Incorporating image processing into PLC system by using microcontroller and relay
Transform signal into PLC processing to classifying the workpieces

GRAPHICAL ABSTRACT

Experimental Investigation of Process Parameters of Al-SiC-B4C MMCs Finished by a Novel Magnetic Abrasive Flow Machining Setup

Gagandeep CHAWLA — 2021-09-13

Abrasive flow machining (AFM) is one of the non-conventional finishing processes used to attain good surface quality and high material removal. However, limited attempts have been made to improve the performance of these processes. This paper presents a novel magnetic abrasive flow machining (MAFM) setup fabricated by adding a magnetization effect in which a nylon fixture and permanent magnets are replaced by a newly fabricated aluminium fixture and coil-type magnets, respectively. Inner cylindrical surfaces of hybrid Al/SiC/B₄C metal matrix composites (MMCs) are finished by the MAFM process. One variable at a time (OVAT) approach is used for studying the effect of 6 input parameters, extrusion pressure (E_p), the number of cycles (N), abrasives concentration (C), workpiece material (W_p), abrasive mesh size (M), and magnetic flux density (M_f) upon response parameters, material removal rate (MRR) and change in surface roughness (ΔRa). The experimental results obtained for MRR and ΔRa show a significant improvement from 3.92 to 7.68 μg/s and 0.49 to 0.74 μm, respectively due to the increase of the extrusion pressure from 1 to 9 Mpa. The MRR and ΔRa was reduced from 6.89 to 6.78 μg/s and 0.46 to 0.22 μm, respectively with an increase in mesh number of abrasives from 80 to 400. The variation in concentration of abrasives from 40 to 60 % shows an improvement in MRR from 4.51 to 6.42 μg/s; whereas, there is a negligible effect on ΔRa which comes out from 3.82 to 3.86 μm. The MMCs, which are used for the experimentation shows a decline in MRR and ΔRa from 5.12 to 3.85 μg/s and 0.77 to 0.42 μm, respectively. This happened because there was a percentage change of reinforcement of SiC from 9 to 7 % and B₄C from 1 to 3 % in Al-6063. An increase in the number of cycles from 50 to 250 shows a significant improvement in both MRR and ΔRa from 1.79 to 3.75 μg/s and 0.97 to 1.86 μm, respectively. Variation in magnetic effect also significantly improves MRR and ΔRa from 1.35 to 3.17 μg/s and 0.38 to 1.06 μm, respectively, when it is varied from 0.15 - 0.45 Tesla. The work carried out shows an overall significant improvement in MRR and ΔRa by using the MAFM process. The MAFM process finds a wide range of applications in finishing like surgical instruments, mechanical components, aerospace industry, electronics industry, etc.

HIGHLIGHTS

The hybrid MMCs (Al/SiC/B₄C) are finished by novel MAFM setup
An aluminium fixture and coil-type magnets play a significant role for finishing the workpiece surfaces
An abrasive laden media acts as a cutting tool in the finishing process
The OVAT approach is used for investigating the parametric effect
The extrusion pressure, number of cycles and magnetic flux density are the significant parameters affecting the MRR and ΔRa

GRAPHICAL ABSTRACT

A Low Noise High Input Impedance Chopper-Stabilized Biopotential Amplifier with Ripple Reduction Technique

Ankit ADESARA — 2021-09-11

Biopotential signals are created as a result of the electrochemical activity of the many cells that comprise the nervous system, and they represent both normal and pathological organ function. These signals must be identified with extreme caution because they are surrounded by a great deal of noise when detected by sensors. This article explores a novel biopotential amplifier that incorporates the chopper stabilization technique to increase noise performance and minimize offset. However, by introducing the chopper modulator into the proposed design, the amplifier's overall input impedance was lowered, which was then increased to greater than 200 MΩ by adding the forward auxiliary path to the input branch. Additionally, the output ripple, produced due to switching activity and up-sampling, was reduced by inclusion of the R-C ripple removing block at the output of the operational transconductance amplifier (OTA). The designed architecture had a mid-band gain of 40dB with a power consumption of 9 µW and an offset of 10µV and a CMRR of 82 dB. It generated a noise of 42nV/√Hz. Also, the obtained results were compared with a conventional amplifier. The proposed design was verified by carrying out simulations using 180nm technology parameters. Cadence Virtuoso (Schematic editor), Spectre (Simulator), Symica and Magic (Layout) tools were used to complete the implementation and simulation of the proposed design.

HIGHLIGHTS

Biopotential signals are created as a result of the electrochemical activity of the many cells which must be identified with extreme caution because they are surrounded by a great deal of noise when detected by sensors
It explores a novel biopotential amplifier that incorporates the chopper stabilization technique to increase noise performance and minimize offset
By introducing the chopper modulator into the proposed design, the amplifier's overall input impedance was lowered, which was then increased to greater than 200 MΩ by adding the forward auxiliary path to the input branch
The output ripple, produced due to switching activity and up-sampling, was reduced by inclusion of the R-C ripple removing block at the output of the operational transconductance amplifier (OTA)
The designed architecture had a mid-band gain of 40dB with a power consumption of 9 µW and an offset of 10 µV and a CMRR of 82 dB. It generated a noise of 42 nV/√Hz

GRAPHICAL ABSTRACT

Application of the Simple Verification Method to Estimate the Weather at Makassar Maritime Station, Indonesia

Didiharyono DIDIHARYONO — 2021-09-13

Verification is used to measure the quality of a weather prediction, improve process performance, and measure the value of weather estimation. Initially, weather verification developed after Finley published his paper on the verification of tornado events. The type of data, objectives, and scale can make a different method in using weather verification. If there are some parameters that can be predicted, a simple question is consequently often asked by the public: how accurate are weather forecasts? Nowadays, the public wants a simple answer in 1 value that is presented quantitatively. The aim of the research is to develop a simple method that can answer the accuracy of weather prediction in a value that is easily understood by the public. Practically, validation comparing between prediction and observation parameters is divided into 2, namely dichotomous and comparing the values. This research tries to combine all weather prediction variables into a dichotomous variable with a threshold. Moreover, this technique is tested on weather predictions for the port of Makassar over a year. The results show that a certain threshold can be used to change the weather variable to be dichotomous. With the application of this method, forecast accuracy and suitability between the predicted parameters can be obtained. Moreover, the weather forecast issued by the Makassar Maritime Station shows the average true value of the forecast to be 69.1 %, and then the capabilities vary by forecasters, which range from 61 to 79 %.

HIGHLIGHTS

Weather forecast verification is used to measure the quality of a weather forecast, improve process performance, and the value of weather forecasts
The character of the weather variables and their predictions is unique and influences the type of evaluation method
To facilitate the public's assessment of the accuracy of weather predictions, it is necessary to combine weather prediction evaluation methods in one value
Using the tolerance threshold whether a deviant prediction is used to combine various weather predictive variables
Average true value of the forecast is 69.1 % and the different capabilities of each forecaster, which range from 61 to 79 %

GRAPHICAL ABSTRACT

A Study of the Extragalactic UV Radiation in Helix Nebula using GALEX

Lakshmi S BOSE — 2021-09-13

We have studied the ultraviolet sources using Galaxy Evolution Explorer medium imaging surveys in Helix Nebula and estimated UV fluxes by using aperture photometry in distant and near ultraviolet bands. The aperture photometric method produces reliable, accurate flux measurements and found inconsistent with the merged catalog of Galaxy Evolution Explorer. From the current results, the fluxes are consistent with brighter absolute magnitude up to 24.5 and the measurement error increases gradually to more than 50 % at the fainter magnitude side. Percentage of error in far UV is greater than near UV, due to the fact that brighter galaxies are more visible than the near UV sources. The diffuse UV contributors of zodiacal light, airglow contribution in the nebula were estimated. The total extragalactic UV radiation from the detected sources to the diffuse background in the nebula is of the order of 50 ± 14 photons cm^-2sr^-1s^-1Å^-1in NUV band and 28 ±10 photons cm^-2sr^-1s^-1Å^-1 in FUV band.

HIGHLIGHTS

GALEX observations have the potential to find extragalactic UV sources
Helix Nebula is first identified for distinct source detection
Aperture photometric method can detect fainter sources up to the magnitude of 27
Extragalactic sources in the Helix nebula contribute to diffuse UV emission in the nebula

GRAPHICAL ABSTRACT

Implementation of 5.1 Sidra Intersection Software for Appraisal of Road Corridors under Current Form

Dagimwork Asele MANUKA — 2021-09-13

The major goal of this study was to compute the flow appearances of the chosen midblock and to evaluate the road sections using various performance metrics that analyzed these road sections in both current and future conditions. Performance measure of flow parameters was at the operational period of the road. Therefore, this work examined the 2-way 2-lane roads with various performance measures. The capacity of mid blocks was also determined by plotting capacity curves and the level of service arrived and Sidra Intersection 5.1 tools were used for the analysis. All midblock evaluated with different performance measures both in current and future conditions with basic considerations. The analysis was done by adopting Sidra Intersection 5.1 tool and showed that 2-way 2-lane roads in future conditions were studied and the result indicated that their average travel speed, degree of saturation, practical spare capacity, total effective capacity, demand of flow, and level of service (LOS) displayed major changes from the base condition.

HIGHLIGHTS

Compute the flow appearances of the chosen midblock
To evaluate the road sections using various performance metrics that analyzed these road sections in both current and future conditions
Performance measure of flow parameters was at the operational period of the road. Therefore, this work examined the 2-way 2-lane roads with various performance measures
The capacity of mid blocks was also determined by plotting capacity curves
The level of service arrived and Sidra Intersection 5.1 tools were used for the analysis

GRAPHICAL ABSTRACT

Soil Chemical Properties and Maize (Zea mays L.) Yield influenced by Lime and Fern (Pteris vittata)

Nguyen Van CHUONG — 2021-09-13

This study aimed to investigate the influence of liming and fern on reducing the absorption of arsenic (As) by maize and As content in the soil. The single-factor experiment was designed in a completely random block (4 treatments and 4 replicates). Treatments were followed: Treatment 1 (NT1) liming (3tons CaO.ha^-1); NT2: Plant ferns alternately with maize (without liming); NT3: Plant ferns alternately with maize and liming (3 tons CaO.ha^-1); NT4: Control (no liming or ferns). The results showed that the applications of liming and ferns have positive influences on the soil pH, EC, OM, yield, and yield components of the maize tested in this study. The yield difference between the application of liming and intercropped ferns was increased from 5.4 to 22.3 %. Moreover, the arsenic contents in soil, stems, and seeds were 25.7, 32.0 and 50 % lower than that of the control, respectively. soil to roots and stems, which significantly caused reduction of a large amount of As content in soils. Therefore, to reduce the production cost, and enhance soil and maize quality, application of lime (3 ton.ha^-1) and intercropped ferns is recommended.

HIGHLIGHTS

Increasing pH, EC and organic matter by the lime application combined with ferns
Decreasing the soil arsenic concentration by intercroping maizes and ferns
The lime application combined with ferns raising the yield components and yield of maize
The high As accumulation of stems and shoots of ferns intercroping maizes and ferns
The lowest As accumulation of stems and seeds of maizes applying the lime combined with ferns

A Single Mutation in the Carbohydrate-Binding Module Enhances Cellulase Activity in Bacillus Amyloliquefaciens Mutant

Nitipol POLSA — 2021-09-13

From our earlier work, we modified the carbohydrate-binding module (CBM) of Bacillus amyloliquefaciens to increase cellulase activity using cold plasma technology. The cellulase gene (BglC-M) from the mutant was expressed in Escherichia coli BL21(DE3) under the T7 promoter. The hydrolysis activity of the cellulase mutant (BglC-M) was approximately 2.5-fold higher than the control (BglC-W) over a wide range of pH and temperature conditions. The amino acid sequence of the mutant BglC-M contained 471 residues that were almost identical to the control BglC-W. Only a single amino acid, lysine, was replaced by glutamic acid at position 370 (K370E) within the carbohydrate-binding module (CBM). Structure prediction and substrate docking of BglC-M indicated that the single mutation (K370E) might involve cellulose binding of the β-sandwich facilitated by hydrogen bonding. The docking study of cellopentaose with the model structure of BglC-M indicated that the replacement of lysine-370 led to the formation of a hydrogen bond with 436Y, which has a shorter distance (2.6 Å) compared with the control (5.4 Å). As a result, the structure becomes more compact and stable, resulting in increased catalytic efficiency. Finally, the biomass hydrolysis ability of cellulase was investigated on lignocellulosic wastes such as pineapple peel, corncob, and durian peel. The BglC-M enzyme showed a more significant amount of reducing sugar released from all lignocellulosic wastes than the control. This was the first evidence that altering the base composition of the cellulose binding module enhanced the catalytic activity.

HIGHLIGHTS

Increasing cellulase activity of Bacillus amyloliquefaciens using plasma technology
Mutation at cellulose-binding module enhance cellulase hydrolysis activity
Greater cellulase activity in the hydrolysis on lignocellulosic wastes

GRAPHICAL ABSTRACT