bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of pH control and uncoupled carbon and nitrogen feeding strategy on enrichment of mixed microbial culture for polyhydroxyalkanoates production
Authors: Khor J W , Yoon L W , Nguyen-Huynh T-Thy , Ng W L , Low J H
Published: July 2023

Polyhydroxyalkanoates (PHA) production via a combination of mixed microbial culture (MMC) and waste carbon substrate has shown to be a more economical solution compared to pure culture process. Although crude glycerol has been proven as a promising feedstock, there are still limited study on the effect of operating conditions such as pH and nutrient feeding strategy on PHA production using crude glycerol. This study aims to investigate the feasibility of enrichment of PHA accumulators in mixed culture without pH control when uncoupled carbon and nitrogen feeding strategy was implemented. Enrichment was conducted in a sequencing batch reactor (SBR) with cycle duration of 24 hr and organic loading rate (OLR) of 1000 mg C/(L.d). Feast and famine strategy was successfully implemented, with feast/famine (F/F) ratio of 0.43 indicating good PHA storage response. The cyclic profile of substrate and PHA concentration has also proven the successful implementation of F/F regime. Biomass concentration of 779 mg/L was obtained by the end of week 5 with PHA content of 16.2% g PHA/g VSS. During the cycle, pH between 6 to 8 was recorded which suggests that extreme acidic or alkaline condition detrimental to PHA accumulators cultivation was not observed in this study. This study demonstrates that enrichment of PHA accumulators is feasible when pH is not controlled under uncoupled C and N feeding strategy.
An investigation to improve the antifouling properties of the Sharklet topography using computation fluid dynamics
Authors: Felicia Wong Yen Myan , Lee Yi Heng
Published: July 2023

Biofouling is an undesirable phenomenon that occurs on the surface that is submerged underwater for a long time. With the adhesion of microorganisms, it will defect indsutrie especially the marine industry. By having biofouling on the submerged surface of vessels, it larger the drag force and friction that are experienced by the vessels while travelling and thus increase the cost on fuel consumption. To deal with this issue, mechanical approach and chemical approach were firstly developed which were then attempting significance success on decreasing the occurrence of biofouling. However, these approaches are not a sustainable solution. Hence, surface modification is then proposed and developed by the researchers to control the biofouling. Currently, Sharklet topography is one of the popular micro-structures antifouling technology. Few studies have presented successful results of Sharklet topography on the antifouling performance, but lack of research is relevant to the way on improving the antifouling properties of Sharklet topography. Thus, this project is mainly on modifying the Sharklet topography and make comparison with the initial design by studying the hydrodynamic characteristics around the surface through Computation Fluid Dynamics (CFD) analysis. To carry out this experiment, three-dimensional (3D) models for the non-patterned surface and Sharklet micro-structured surfaces will be created in different channels of flow but with similar settings. The data to be identified and compared from both models are flow velocity, shear strain rate and wall shear stress. From this study, it is observed that as varying the sizes of width between the effective range of microtopography sizes (64 μm – 264 μm) under constant height and spacing, the bigger the size of width, the better the performance of antifouling since the wall shear aspect appears the sharp fluctuation for the geometry with aspect ratio of 1.5 as compared 2.0 and 3.0. With the sharply fluctuating shear stress, it will be an unfavorable environment for the microorganisms to settle down.
Design and development of an automated glove inspection machine
Authors: Chua Yue Le , Choo Hui Leng , Nazimudin Kasoo Raheel , Lim Eng Wei
Published: July 2023

Gloves are commonly used as personal protective equipment (PPE) to protect humans from contact of contamination of chemical substances and infection of disease such as Covid-19. The gloves markets including household gloves upsurged exponentially during the Covid-19 outbreak as the concern and awareness of safety and hygiene rises in the community. Hence, to ensure the safety and reliability of the product, quality control of the gloves must be efficient and accurate. However, most of the household glove manufacturers are still using manual visual inspection for quality control, which is unreliable and expensive as cost of labor are gradually increasing too. Therefore, the aim of the project is to develop an automated machine that can inspect varied sizes of household gloves and segregate the defective with non-defective gloves. With the implementation of automated glove inspection machine, the efficiency and return-of-investment for the glove inspection process can be increased. Throughout the project, the 3D model of the inspection device was developed and fabricated using 3D printing technology. Automated system of glove inspection and segregation was implemented on the inspection device. Then, the inspection device was tested on industrial defective gloves and self-made defective gloves with different diameters of pinholes. Results show that the inspection device was able to segregate all defective gloves from the non-defective gloves. The inspection device was duplicated with four more sets and mounted onto the rotating platform to complete the automated glove inspection machine. The final automated glove inspection machine can inspect and segregate five household gloves consecutively on each cycle to increase the efficiency and ROI of the quality control.
The Application of Image Processing for Conversion of Handwritten Mathematical Expression
Authors: Iskandar Nasuha , Chew Wei Jen , Phang Swee King
Published: July 2023

Optical character recognition (OCR) is the conversion of printed or written text from a scanned document or image file into a machine-readable form to be used for data processing like editing. Handwriting has been a way of communication for centuries, but modern technology has made it easier with the introduction of modern computers. While people have adapted to typing out words using a keyboard, formulas and mathematical expressions requires additional add-ons installed in the word processor. The process can be time consuming and tedious. Therefore, an alternative method is proposed in this paper in which handwritten mathematical formulas are converted into computer readable text. Horizontal and vertical projection is used for segmentation while convolutional neural network for character recognition is used to increase the recognition accuracy. The proposed method was able to segment out handwritten mathematical equations from lined papers as well as extract out and identify each character written. The handwritten equation was then successfully converted to a digital format.
Angular Stability Enhancement of Grid Integrated Wind Energy Using PSO to Optimize PSS
Authors: Alhinai Ahmed Mohammad Salim , Vaithilingam Chockalingam Aravind , Alsakati Ahmad Adel , Rajendran Gowthamraj , Raja Venkatesh Krishna , Kamalakkannan S.
Published: July 2023

The majority of nations are making efforts to protect our planet by reducing emissions caused by the combustion of fossil fuels to create energy and increasing the production of green power from renewable energy sources. Wind energy is one of the renewable energy sources that is the least destructive to the environment and an efficient approach to reducing carbon emissions. Wind power is also one of the renewable energy sources that are the most cost-effective. However, even though wind energy has been employed for quite some time, there are still some challenges that this form of renewable energy must overcome, such as maintaining the stability of the power grid. The primary objective of this research is to enhance the transient stability of the power system by utilizing an optimized power system stabilizer (PSS) that has been improved. The purpose of this study is to investigate the effect that wind power has on the reliability of power systems that are outfitted with PSS and also to optimize the parameters of the PSS to increase the network’s reliability in two different domains. While PSS with the ST1A excitation system is utilized to reduce the transient period and peak value, oscillations of the generator’s speed deviation can be dampened. Through the management of the relative power angle stability of the network, the major objective of PSS is to enhance the performance of the system.
Influence of the Formulated Surfactant on the Characterization of the Base Oil
Authors: Leng Lai Yee , Anisa Nor Ilia , Nour Abdurahman Hamid
Published: July 2023

An emulsion is defined as a phase containing two immiscible liquids consisting of water and oil. In the oil and gas industry, the presence of emulsions results in high costs for pumping equipment, reduced performance and increased corrosion rates in pipelines and other equipment. Numerous studies have been conducted for crude oil emulsions, but are still lacking for emulsions present in base oil. Therefore, the research focuses on characterising the emulsified base oil by comparing the physical and thermophysical properties of the emulsified base oil with and without a formulated surfactant and using the base oil as a control sample to observe the stabilisation of the samples. Physical properties include material composition, particle size and distribution, density, viscosity and shear stress; thermophysical properties include thermal stability. Samples were prepared using a homogeniser (2 hours) followed by ultrasonic treatment (2 hours) with 10 mL of water and 190 mL of base oil at room temperature. About 10 mL of the formulated surfactant was added to characterise the emulsified base oil with surfactant. The samples were further analysed for molecular compounds, particle distribution, physical properties (density and viscosity) and thermal stability using DSC and TGA. The results showed that the emulsified base oil with formulated surfactant has higher viscosity and lower density than the emulsified base oil without formulated surfactant.
Fast 3D Mapping Solution with UAV
Authors: Shahid Ismail Ghalif , Phang Swee King , Chew Wei Jen
Published: July 2023

The photogrammetric method of 3D mapping uses Structure from Motion (SfM) algorithm, where 3D structures of a scene are created from 2D sets of data taken from multiple angles. This 3D mapping process is used in many advanced and important applications in the digital and robotics industry. The use of omnidirectional camera along with UAV for this photogrammetric process allows faster data acquisition and data processing to construct 3D structures compared to traditional method. However, the metric accuracy of spherical photogrammetry is relatively less compared to traditional framed camera photogrammetry. Hence, this research will focus on improving metric accuracy of spherical photogrammetry by enhancing SfM algorithm for the purpose of providing an enhanced and value-added fast 3D mapping solution using UAV. The research was conducted at 4 main levels. 1) Data acquisition phase, where the 360-degree camera with GPS tracker are attached to a UAV, and it is used to collect different sets of images at different heights and angles. 2) Camera calibration, for the purpose of identifying the camera intrinsic and extrinsic. These 2 parameters are crucial in feature detection and camera position estimation. 3) Data processing phase, where the collected data would be processed through the enhanced SfM algorithm to create the 3D structures. 4) Data analysis phase, where the 3D model created from enhanced SfM algorithm would be compared against a reference 3D model created by commercial software. However, the results attained were not as expected due to undesired feature detection process. This research is expected to help geographical and land surveyors to conduct surveys at a faster, more efficient and at a higher accuracy. A practical use case of this solution is to survey the terrain of an area under natural disaster, accurately and faster for search and rescue missions.
The Investigation Of The Synthesis Cooking Oil As A New Power Transformer Oil
Authors: Subramaniam Sarrvish , Ahmad Hafisoh , Bakar Nurfarhanim Abu , Haris Faranadia Abdul , Rahman Rahisham Abdul
Published: July 2023

Background: The mineral oil has been widely used in a power transformer for the purpose of insulation and suppression of corona and arcing. But due to its extremely low flashpoint, this can also cause an explosion in the case of a fire and the mineral oil has been found to be non-biodegradable. In this research, an alternative of mineral oil is proposed, which is the usage of used cooking oil which will undergo chemical modification via transesterification in order to achieve its expected properties which fits into the requirements of the power transformer according to the IEEE standard of IEEE C57.147

Methods: the synthesis of oil process will begin by the selection of the most suitable vegetable oil, in this case the palm oil in which, the water content and acidity were taken into consideration. The oil will then undergo transesterification process for the removal of free fatty acids and water content, before being tested for its acidity, water content and the breakdown down voltage in the high voltage lab to evaluate the electrical properties of the oil.

Results: The results obtained during testing is that the breakdown voltage and water content is 6 kV and 125 ppm and the acidity 0.13 mg KOH/g.

Conclusion: It is expected that the potential synthesized oil which has undergone transesterification process and the removal of all water content and free fatty acids in the oil, can be able to replicate the values replace the mineral oil in a power transformer despite having a higher acidity than the mineral oil.
The Application of Image Processing to Determine Lift Occupancy
Authors: Nasir Nur Asyiqin Mohamad , Chew Wei Jen
Published: July 2023

Lifts have become an essential device to move people up and down tall buildings every day. However, sometimes the lift still stops even though it is already fully occupied, either with people or objects, and is not able to take in more passengers. This makes the amount of time used to get to a floor longer due to all the unnecessary delays. As a result, the primary emphasis of this research endeavour is placed on the application of image processing techniques, namely those that make use of the tracking system that uses Kalman filter, to track moving people and objects, to determine the occupancy of a lift. Kalman filter is applied to accurately track and determine whether it is a person or an object that is located within the bounding boxes. If it is a person, an estimate of the amount of space that an average human occupies in a given environment is determined. In contrast, if it is not a human, then the usage of the polygon function will be incorporated to estimate the percentage of space that is occupied by the items. This will be done in order to figure out how much space the objects take up. Through the use of the proposed system, the occupancy of the lift is determined by analyzing still images taken from a video that was recorded by a camera located within the lift. As a consequence of this, the average travel time for a lift user can be reduced with the reduction of unnecessary stops while it is fully occupied.
Alula Effect on Aerodynamic Performance of Small UAVs Wing Configuration
Authors: Eftekhari Shahrooz , Al-Obaidi Abdulkareem Sh. Mahdi , Mari Tamil Salvi
Published: July 2023

The application range of small UAVs for civil purposes such as aerial imaging, agricultural pest control and, corps management as well as drone delivery has been increasing throughout recent years. Promising results are observed from recent studies which support the effectiveness of the bio-inspired approach in improving the aerodynamic efficiency of small UAVs. However, very limited studies have investigated the effect of Alula on the aerodynamic performance of wing geometries. This research investigates the effects of employing Alula on the aerodynamic efficiency of the wing to overcome the challenge of small UAVs efficiency degradation. Numerical and experimental investigations are conducted on 6 different Alula configurations. The findings of the investigations shows a reduction in drag for wings and an increase in aerodynamic efficiency by 9% for wings with Alula compared to the conventional wing. It is observed that using Alula configuration helps in delaying flow separation by adding momentum into the flow which resulted in total drag reduction without having a significant effect on the lift. Consequently, the aerodynamic efficiency is increased, and this can be utilized in drone industry to increase the endurance of the flight.
Greenwall Filtration System for Lakewater Treatment: A Case Study on Cocopeat/Perlite Filter Media
Authors: Gan Chloe Vera Li Yi , Tee Lee Hong , Oh Kai Siang , Lam Weng Hoong , Yoon Li Wan , Phang Eunice Siew Wei
Published: July 2023

Anthropogenic activities often result in varying degrees of lakewater contamination. Conventional lakewater treatment processes require expansive space allocation which could be challenging under certain topographical situations. A greenwall filtration system is a vertical wall that consists of plants or greenery. In this system, greenery is planted in a growing medium made up of a combination of soil, stone, or water. A robust greenwall filtration system could serve as a potential solution for lakewater treatment. However, the efficacy of various filtering media in eliminating contaminants and various water quality indicators such as Chemical Oxygen Demand (COD) from lakewater remains unknown. Previous research has demonstrated that coir and perlite are suitable filter media for a greenwall system. In this study, the effects of various height ratios of the filter media and different lakewater flowrates were investigated. The treatment performance was assessed using various lakewater flowrates: low flowrate (13.10 L/h), medium flowrate (26.57 L/h) and high flowrate (45.18 L/h). The mixed media ratio of 3:1 cocopeat-to-perlite during low flowrate (13.10 L/h) attained the highest removal of COD with an overall removal of 71.00%. It was further discovered that the Langmuir isotherm model could better explain the adsorption process than the Freundlich isotherm model as it possesses an overall high coefficient of determination, R2
where the value of R2
for cocopeat to perlite ratio at 1:1, 1:3, and 3:1; are 0.9397, 0.9823, and 0.5348, respectively.
Finite Element Analysis of Sn-58Bi Shear Test
Authors: Leong Michelle Mei Kit , Amares S
Published: July 2023

Finite element analysis (FEA) of quasi-static single lap shear test was conducted to study the mechanical properties of Sn-58Bi in terms of deformation, strain, stress, yield strength and ultimate strength. The study generated results of simulated behaviour of low temperature Sn-Bi solder alloy to address the demand of low temperature solder alloys in the electronic industry. The geometry was constructed in SolidWorks based on ASTM D1002 standard before being imported to ANSYS. The simulation was conducted at shear velocity of 0.1, 0.5, 1 and 1.27 mm/min and temperature of 138, 178, 208 and 238 °C using ANSYS. The simulation results were compared with the corresponding experimental results. Simulation results showed that an increase in shear velocity caused a decrease in ultimate strength and an increase in ductility of Sn-58Bi. As the velocity increased from 0.5 to 1.27 mm/min, the ultimate strength decreased from 339.87 to 291.24 MPa. This is predicted due to the Bi-rich layer within the lamellar structure of Sn-Bi alloy. An increase in temperature caused an increase in ultimate strength and brittleness in Sn-58Bi due to the trans-granular propagation of brittle failures along the weak Bi-abundant phase. As the temperature increased from 138 to 238°C, ultimate strength increased from 290.46 to 298.93 MPa.
The geometrical and Möbius-invariant properties of parabolic cycles
Authors: Gupta Sneha , Biswas Debapriya
Published: July 2023

We have studied parabolic cycles and given their equivalent matrix representations. Invariant properties of matrices under similarity have contributed to the Möbius-invariant properties in cycles. We have further discussed the inner product in the cycle space. Also, the geometrical properties of orthogonality and reflection have been studied to obtain the irregular points in the cycle space.
Mathematical Modeling of pedestrian flow through the obstacle bottleneck
Authors: Jia Xiaolu , Yanagisawa Daichi , Feliciani Claudio , Nishinari Katsuhiro
Published: July 2023

For pedestrians in walking facilities, their movements are often obstructed by bottlenecks where the walkable widths are geometrically reduced. In previous research, to reproduce the influence of bottlenecks on pedestrian movements, agent-based simulation models have been widely applied. However, their high reliability on modeling rules and parameters requires calibration at the microscopic level, which makes them difficult to apply from an engineering perspective. Here, we applied a mathematical approach, which estimates the egress efficiency based on the density-flow rate fundamental diagram, to reproduce the egress time of pedestrians in our field experiments. Both the obstacle and the exit were considered bottlenecks in our experiments. It was indicated that with the same width, the obstacle bottleneck acted as an ‘ineffective’ bottleneck that did not affect the egress time when it was near the exit bottleneck, whereas acted as an ‘effective’ bottleneck when it was distant from the exit bottleneck. To reproduce this phenomenon, we applied a mathematical approach that abstracts the walking scenario as a scheme with the bottlenecks as links and different regions as nodes. As a result, the egress times under different layouts were reproduced successfully by introducing the density-flow rate fundamental diagram into the scheme. Furthermore, a reasonable range of the obstacle size and obstacle-exit width, under which condition the egress time is constant, was estimated. This study can be applied to estimate the egress time of the walking facilities by considering the fundamentals of pedestrian flows from a mathematical perspective, thus helping in the actual design of bottlenecks that could ensure efficient and safe pedestrian egress in walking facilities.
Utilizing GOES-16 instruments to forecast geomagnetic storm during Solar Cycle 25
Authors: Rossdee Anis , Hamidi Z S , Shariff N N M
Published: July 2023

This paper focuses on the study of active region AR12891 in conjunction with geostorm from space weather data. A flare of magnitude M1.7 occurred in this active region, resulting in a geomagnetic storm of magnitude 3. By observing solar activity, x-ray flux, and radiation particle monitoring, GOES-16 instruments were used to forecast these events. A python program was used to analyze data collected from the online database of solar monitor and space weather live provided by the NOAA. Solar flare events can be studied and monitored through GOES-16 instruments to forecast geomagnetic storms. This allows less impacts towards satellite navigations and power sources if geomagnetic storm was detected early.
Atomic hydrogen adsorption on freestanding α-borophene nanoribbons for hydrogen spillover applications: Insights from density functional theory calculations
Authors: Santos-Putungan A B , Herrera M U , Putungan D B
Published: July 2023

In this work, we probed the applicability of α-borophene nanoribbon as a spillover hydrogen host material using density functional theory (DFT) calculations. It is found that all top sites, along the edges and on the planar surface, are appropriate for hydrogen physisorption. On the other hand, the hollow site which is a defining feature of the α-borophene nanoribbon, was found to be an unstable adsorption site for hydrogen, and does not act as a trap site for hydrogen atom. Density of states calculations show that the broadening of the hydrogen 1s states made it possible for a good hybridization with the boron 2p states, allowing for such a moderate hydrogen physisorption. The resulting moderate adsorption energies indicate good hydrogen migration properties, making α-borophene nanoribbon a very good candidate material for spillover hydrogen applications and could be utilized as a key material for overall hydrogen storage.
An analysis of slow drift type II radio burst and its association with full halo coronal mass ejection on 12th January 2022
Authors: Shamsuddin SNA , Ansor NM , Hamidi ZS , Shariff NNM
Published: July 2023

Radio bursts have been a point of contention among astrophysicists in the modern era. Solar flares, coronal mass ejections (CMEs), and solar energetic particles (SEPs) that project from the Sun to interplanetary space can all be observed using this method. Based on data from e-Callisto, we detected a type II radio burst on 12th January 2022 starting at 04:24 UT and lasting until 04:56 UT. The full image of radio burst type II (SRBTII) was compiled from two stations (Almaty and Australia-ASSA), the drift rate of the bursts calculated are -0.07796 MHz/s and - 0.105822893 MHz/s respectively, and the relevant solar activity was determined. There was a possible association between the observed burst and the halo CME event on the day. This study includes the properties of the CME and the D-region Absorption Prediction (D-Rap) plot as the signal degradation indicator caused by the solar flare and CMEs to demonstrate its significance in understanding the impact on Earth’s atmosphere.
Power-frequency performance of step-graded double Gunn diodes
Authors: Butts L J , El-Ghazaly S M
Published: July 2023

Simulations of conventional Gunn diodes containing the double Gunn effect have shown a significant increase in oscillation frequency and frequency range. However, conventional Gunn diodes suffer from higher phase noise, lower efficiency, and reduced temperature stability due to the lack of a hot electron injector. A study on the performance of a Double Gunn diode with a graded gap injector is presented. The second region of negative differential mobility is gradually introduced in several temperature-dependent mobility models, which are implemented in an energy balance simulation. Devices with transit lengths of 0.7μm, 1.1μm, and 1.65μm are simulated. All devices experience an increase in oscillation frequency with increasing intensities of the double Gunn effect. The frequency range doubles at significant intensities of the effect in the devices with transit lengths of 0.7μm and 1.65μm.
Protection of Substation Grounding Grid by Gadolinium Magnesium Sacrificial Anode
Authors: Peng Dingda , Liu Ruilong , Huang Wenxun , Wang Xiaobo , Xia Fubing , Zhai Zhe
Published: July 2023

Since lower galvanic efficiency and potential reversal might occur in magnesium (Mg) sacrificial anode applied in anti-corrosion project for grounding grid in substation, rare earth gadolinium (Gd) was incorporated into Mg sacrificial anode material for activating and improving the performance of the anode, and the influence of Gd concentration on properties of Mg sacrificial anode was evaluated by electrochemical method. The results revealed that the incorporation of Gd could effectively improve the electrochemical properties of magnesium sacrificial anode. The present of 0.1%(wt) Gd in the anode caused the best electrochemical properties as follows: the OCP decreased to as low as -1.78V (SEC) while the galvanic efficiency increased to as high as 62%, and the minimal anodic corrosion current, 0.0186mA, was realized, also the reverse potential and current density in DC leakage process increased from 500mV to 900mV and 1mA/dm2 to 2.27mA/dm2, respectively.
Research on Bulk Acoustic Wave Resonator Based on Phononic Crystal
Authors: Shuang Wang
Published: July 2023

With the continuous advancement of information technology and the rapid development of mobile communication technology, from smart home to automatic driving of cars, and then to the application and development of virtual reality, communication technology has evolved from the earliest communication between people to communication between things. The frequency band supported by smart phones and various small mobile terminals is increasing, and their communication frequency is also gradually increasing, which brings some challenges to the traditional RF front-end devices. The traditional RF filter can not meet the current market demand because of its own performance and size constraints. As the best option to integrate with RF circuit or microwave circuit, bulk acoustic wave filter has great development and application prospects in modern RF communication system. This paper will focus on the solid-state assembled resonators based on one-dimensional and two-dimensional phononic crystals, analyze the influence and change law of the performance of bulk acoustic wave devices based on two-dimensional phononic crystals, then explore the main loss mechanism existing in solid-state assembled devices, and propose improvement schemes, which lays a foundation for the application of solid-state assembled resonators in today’s RF front-end.
Timer Switching Control Applied to Municipal Water Pumping System
Authors: Ngancha P B , Kusakana K , Markus E D
Published: July 2023

In this paper, the timer control and the inverter control of the pumping system are modelled and simulated. The effects of evaporation, rainfall and seepage are considered to make the model more practical. The proposed timer control model and VFD are used to control the motor pump, which saves a lot of cost. MATLAB/SCIP optimization software was used to implement the developed model. Simulation was used to assess the performance of the proposed electrical timer switching control system. Two scenarios were used to simulate the model: first, a timer control system was applied to a fixed speed water pump, and second, a timer control system was integrated with the VFD power control pump. The simulated results are compared in order to calculate the developed model economic benefit. In comparison to the baseline case, where the load demand is met using a timer control model with a fixed speed motor pump, the simulated results for the given day of operation demonstrate that employing the suggested timer control model with a VFD control motor pump can save 706 ZAR in operating cost each day.
Optical property measurements of lithium chloride aqueous solution for a novel solar neutrino experiment
Authors: Liang Ye , Xu Tong , Zhang Jialiang , Li Shuo , Qi Ming , Wang Zhe
Published: July 2023

The lithium chloride aqueous solution has great potential to
be the detection medium of a novel solar neutrino detector. The
nuclide 7Li provides a charged-current interaction channel with a
high cross-section for the MeV-scale solar electron-neutrinos,
enabling measurement of the solar neutrino spectrum. This work
measures the optical properties and the light yields of a saturated
lithium chloride solution. After adsorption with activated carbon
and recrystallization, the solution shows little absorption in the
sensitive wavelength range of the bialkali photomultipliers. The
attenuation length is evaluated to reach 50 meters at 430 nm. In
addition to being a pure Cherenkov detector medium, a wavelength
shifter, carbostyril 124, is added to the LiCl aqueous solution. The
compatibility and the enhancement of the light yield are confirmed,
enabling the development of a water-based Cherenkov-enhanced
lithium-rich detector.
Design and implementation of a temperature-compensated corrector magnet power supply for the Taiwan Photon Source
Authors: Wang Baosheng , Liu Chenyeo , Liu Kuobin , Wong Yongseng
Published: July 2023

The Taiwan Photon Source (TPS) is a widely recognised 3 GeV
synchrotron light source. It has demonstrated exceptional
performance in average beam downtime and meeting international
standards over its successful ten-year operation. Regular equipment
updates are conducted for all subsystems to ensure continuous
improvement and maintain an optimal research facility
environment. This study focuses on designing and implementing a
temperature-compensated corrector magnet power supply for the
TPS. The power supply incorporates a high-bandwidth, compact,
cost-effective, bipolar, and highly precise shunt resistor as the
current feedback component. A temperature control copper box and
temperature compensation circuit are employed to improve the thermal
equilibrium time of the output current. A laboratory-developed
TPS-corrected magnet power supply with temperature compensation
control has been successfully developed through these measures. The
prototype exhibits a maximum output current of 10 A and operates at
a voltage of 40 V. Metal-oxide-semiconductor field-effect
transistors (MOSFETs) are utilised as the power switch in a
full-bridge (H-bridge) configuration with a driving frequency of
40 kHz. The output current ripple is effectively maintained at
100 μA for a 10 A output, and the stabilisation time is
achieved within 5 minutes. The control loop design of the prototype
has been verified to achieve fast and stable output current
performance. The completed prototype demonstrated a -3 dB
bandwidth of 2.57 kHz when tested with an input reference signal of
0.1 V. Finally, a hardware prototype circuit was constructed in the
power supply laboratory, featuring an input voltage of 48 V, an
output current of 10 A, and a maximum power capacity of 400 W.
Recent peat and carbon accumulation on changing permafrost landforms along the Mackenzie River valley, Northwest Territories, Canada
Authors: Germain Chartrand Pénélope , Sonnentag Oliver , Sanderson Nicole K , Garneau Michelle
Published: July 2023

Northwestern Canada is currently warming nearly four times faster than the global average, driving accelerated permafrost thaw and changes to ecosystem vegetation, hydrology and landscape structure across the landscape. While permafrost peatlands constitute a large carbon reservoir, there is no consensus yet on the direction and magnitude of changes to their vulnerable carbon balance. Here, we assessed changes in peatland ecosystems following permafrost thaw at three sites located along a 1000 km long climate and permafrost gradient along the Mackenzie River valley, Canada. Specifically, we examined vegetation succession over the last few decades to evaluate the possible impact of climate warming on peat and carbon accumulation. Results from the palaeoecological analysis of 20 surficial peat cores, supported by robust chronologies, show a return to Sphagnum accumulation since ca. 1980 CE in the sporadic and discontinuous permafrost zones and ca. 2000 CE in the continuous permafrost zone. The average rates of peat and carbon accumulation reached 4 mm yr−1 and 134 g C m−2 yr−1 at the northernmost site in the continuous permafrost zone. In contrast, peat and carbon accumulation reached 3 mm yr−1 and 81 g C m−2 yr−1, respectively, in the sporadic and discontinuous permafrost zones. This study highlights the need for a net carbon budget that integrates the recent accelerated Sphagnum growth and carbon uptake from the atmosphere to better assess the potential carbon emissions offset following permafrost thaw. High-resolution palaeoecological studies can offer insights into decadal-scale patterns of vegetation and carbon balance changes to improve model predictions of peat climate-carbon cycle feedbacks.
Deviation of geodesics and particle trajectories in a gravitational wave of the Bianchi type VI universe
Authors: Osetrin K E , Osetrin E K , Osetrina E I
Published: July 2023

For the Bianchi type VI universe, exact solutions of the equation of geodesic deviation in a strong primordial gravitational wave in a privileged coordinate system are obtained. The solutions refer to Shapovalov’s gravitational-wave models of spacetime and allow the existence of complete integrals of the Hamilton–Jacobi equation for test particles. For all the solutions obtained, the analytical form of the tidal acceleration vector in a strong primordial gravitational wave is obtained. An explicit form of the coordinate transformation, an explicit form of the metric of the primordial gravitational wave of the Bianchi type VI universe, and the form of the tidal acceleration vector in the laboratory synchronous coordinate system are obtained. The synchronous coordinate system is associated with a freely falling observer and allows the observer to separate time and spatial coordinates, as well as to synchronize time at different points in space. The presented mathematical approach can be applied both in the general theory of relativity and in modified theories of gravity.
The bioengineering of perfusable endocrine tissue with anastomosable blood vessels
Authors: Yago Hiroki , Homma Jun , Sekine Hidekazu , Higashi Yuhei , Sakurai Hiroyuki , Shimizu Tatsuya
Published: July 2023

Organ transplantation is a definitive treatment for endocrine disorders, but donor shortages limit the use of this technique. The development of regenerative therapies would revolutionize the treatment of endocrine disorders. As is the case for harvested organs, the ideal bioengineered graft would comprise vascularized endocrine tissue, contain blood vessels that could be anastomosed to host vessels, have stable blood flow, and be suitable for transplantation into various sites. Here, we describe a transplantable endocrine tissue graft that was fabricated by ex vivo perfusion of tricultured cell sheets (islet β-cells, vascular endothelial cells (vECs), and mesenchymal stem cells (MSCs)) on a vascularized tissue flap of in vivo origin. The present study has three key findings. First, mild hypothermic conditions enhanced the success of ex vivo perfusion culture. Specifically, graft construction failed at 37 °C but succeeded at 32 °C (mild hypothermia), and endocrine tissue fabricated under mild hypothermia contained aggregations of islet β-cells surrounded by dense vascular networks. Second, the construction of transplantable endocrine tissue by ex vivo perfusion culture was better achieved using a vascular flap (VF) than a muscle flap. Third, the endocrine tissue construct generated using a VF could be transplanted into the rat by anastomosis of the graft artery and vein to host blood vessels, and the graft secreted insulin into the host’s circulatory system for at least two weeks after transplantation. Endocrine tissues bioengineered using these techniques potentially could be used as novel endocrine therapies.
Noncanonical binding of transcription factors: time to revisit specificity?
Authors: Samee Md. Abul Hassan
Published: July 2023

Transcription factors (TFs) are one of the most studied classes of DNA-binding proteins that have a direct functional impact on gene transcription and thus, on human physiology and disease. The mechanisms that TFs use for recognizing target DNA binding sites have been studied for nearly five decades, yet they remain poorly understood. It is classically assumed that a TF recognizes a specific sequence pattern, or motif, as its binding sites. However, recent studies are consistently finding examples of noncanonical binding, that is, TFs binding at sites that do not resemble their sequence motifs. Here we review the current literature on four major types of noncanonical TF binding, namely binding based on DNA shape readout, at Guanine-quadruplex structures, at repeat sequences, and bispecific binding. These examples point to a critical need for studies to unify our current observations, many of which are at odds with the “one TF, one motif” view, into a more comprehensive definition of the DNA-binding specificity of TFs.
Exploring Interaction in Video-call Paired Speaking Tests: A Look at Scores, Language, and Perceptions
Authors: Lee Hye-won , Mullooly Andrew , Devine Amy , Galaczi Evelina
Published: July 2023

In the assessment of second language oral communication, the video-call speaking test has received increasing attention as a test method with higher practicality than its in-person counterpart, but still with broad coverage of the test construct. Previous studies into video-call assessment have focussed on the individual (as opposed to paired or group) interactional format. The current study extends this line of research by focussing on paired speaking interactions, with a specific focus on the construct of interactional competence. A concurrent triangulation design was adopted with the use of both quantitative and qualitative data through recordings and scores of test performances, questionnaires, and focus groups. Findings indicate that video-call paired interactions in the assessment context of interest in this study are largely comparable to in-person interactions in terms of scores, with statistically small-effect size differences identified. Some differences in terms of turn-taking management, examiner, and test-taker perceptions were also identified. We argue for a more in-depth awareness of the characteristics of video-call speaking in its own right, which can inform both assessment and learning contexts.
A case report of self-audible pericardial rub secondary to acute pericarditis from post-pericardiotomy syndrome (pericardial rub tinnitus)
Authors: Ibrahim Ramzi , Ferng Jonathan , Pineda J R Exequiel , Lee Kwan
Published: July 2023

Background

Pericarditis is a common pericardial disorder that is frequently accompanied by a pericardial friction rub, which can be detected during a physical examination. Although patients’ awareness of cardiac murmurs and vascular bruits has been extensively reported, there are no reports on patients’ self-awareness of a pericardial friction rub.

Case summary

We present the first case of a patient with acute pericarditis associated with objective self-awareness of a pericardial friction rub, which we recorded with an electronic stethoscope and confirmed the sound with the patient. The patient had a recent history of three-vessel coronary artery bypass grafting and presented with a progressively worsening, rhythmic, and ‘sandpaper-scratching’ sound in both ears. The sound was more pronounced in the left lateral decubitus position. The symptom resolved with colchicine therapy and was associated with concomitant resolution of the pericardial friction rub.

Discussion

This is the first documented case of a patient demonstrating objective self-awareness of a pericardial rub resulting from acute pericarditis associated with post-pericardiotomy syndrome. Tinnitus refers to the perception of an auditory sensation that can be subjective or objective, depending on whether it is heard only by the individual or can also be heard by an observer. While objective tinnitus caused by cardiovascular conditions has been previously reported, no cases have attributed the pericardial friction rub as the underlying cause. Therefore, we suggest using the term pericardial rub tinnitus to describe this unique phenomenon.
Autolytic attempt mimicking Brugada type 1 electrocardiogram pattern due to flecainide toxicity. A case report
Authors: López Guillén José Luis , Sastre Albiach José Manuel , Torres García María Begoña , Maravall Llagaria María Dolores
Published: July 2023

Background

Brugada phenocopies are a group of heterogeneous disorders that mimic Brugada syndrome (BrS) electrocardiogram (ECG) changes elicited by reversible clinical conditions. We report a novel case on flecainide toxicity causing an ECG signature of Brugada type 1 pattern in the paediatric age.

Case summary

A 13-year-old Caucasian boy with untreated attention-deficit/hyperactivity disorder referred to the Pediatric Emergency Department (PED) after unknown antiarrhythmic drug overdose. He deliberately ingested 10 tablets from a labelled white box of a 100-mg single dose. The ECG showed a coved-type ST-segment elevation in right precordial leads and prolongation of PR segment with a QTc limit interval. Values of troponins gradually increased and echocardiogram was normal. The altered ECG pattern was explained by the stabilizing membrane effect of flecainide involving the inhibition of rapid Na+ channels. After offending drug removal, regression of ECG changes was observed and no cardiac events were documented during follow-up.

Discussion

Flecainide-induced Brugada type 1 ECG pattern may occur in patients with no evidence of genetic susceptibility receiving a toxic dosage of this drug. With increasing dose, its action on conduction pathways manifests as prolongation of PR interval and QT and QRS complex duration and may cause BrS mimicry. A detailed clinical history considering symptoms and ECG findings may support early-raised suspicion for flecainide ingestion. The therapeutic approach implies primary detoxification, prevention of potential triggers, and management of eventual cardiotoxicity events. Finally, risk stratification for BrS should be always measured according to the clinical scenario and surveillance considered in a timely manner.
Multiple mechanisms contribute to isolation-by-environment in the redheaded pine sawfly, Neodiprion lecontei
Authors: Bagley Robin K , Hurst Melanie N , Frederick Jeremy , Wolfe Jordan , Terbot John W , Frost Christopher J , Linnen Catherine R
Published: July 2023

Isolation by environment (IBE) is a population genomic pattern that arises when ecological barriers reduce gene flow between populations. Although current evidence suggests IBE is common in nature, few studies have evaluated the underlying mechanisms that generate IBE patterns. In this study, we evaluate five proposed mechanisms of IBE (natural selection against immigrants, sexual selection against immigrants, selection against hybrids, biased dispersal, environment-based phenological differences) that may give rise to host-associated differentiation within a sympatric population of the redheaded pine sawfly, Neodiprion lecontei, a species for which IBE has previously been detected. We first characterize the three pine species used by N. lecontei at the site, finding morphological and chemical differences among the hosts that could generate divergent selection on sawfly host-use traits. Next, using morphometrics and ddRAD sequencing, we detect modest phenotypic and genetic differentiation among sawflies originating from different pines that is consistent with recent, in situ divergence. Finally, via a series of laboratory assays – including assessments of larval performance on different hosts, adult mate and host preferences, hybrid fitness, and adult eclosion timing – we find evidence that multiple mechanisms contribute to IBE in N. lecontei. Overall, our results suggest IBE can emerge quickly, possibly due to multiple mechanisms acting in concert to reduce migration between different environments.
The Tripwire Effect: Experimental Evidence Regarding U.S. Public Opinion
Authors: Musgrave Paul , Ward Steven
Published: July 2023

Claims about the deterrent role of forward military deployments often depend on the argument that attacks on troops stationed abroad will activate a “tripwire effect.” It is assumed that this effect would generate strong domestic pressure for further military intervention by the country whose troops have come under attack. In theory, the anticipation of a strong tripwire effect prospectively ties the hands of leaders, thereby bolstering the reliability of extended deterrent threats and promises. In this paper, we define the tripwire effect and use both conjoint and vignette survey experiments to evaluate its operation and magnitude among Americans. Results suggest that the tripwire effect is, at best, far weaker than many analysts and policymakers commonly assume. This finding raises serious questions about a core logic underpinning the United States’ forward military posture and highlights the need for more research on the deterrent functions of forward deployment.