bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and manufacture of a radiative cooler to measure the subambient cooling effect and cooling power
Authors: Qin Jie , Zhang Zihan , Li Yanwen , Cai Yuanzhu , Zhang Hongqiang , Liu Lianhua , Xu Lijin , Zhang Weidong , Xue Xiao
Published: May 2022

The obscure theory of passive subambient daytime radiative cooling (PSDRC) was deduced in a more understandable way using an arithmetic formula rather than integro-differential equations. Based on two boundary conditions of the equations, an innovative radiative cooler was successfully developed to qualitatively observe PSDRC phenomena and quantitatively characterize the cooling effect and cooling power of radiative cooling coatings (RC coatings). The remarkable subambient temperature reduction over 4.0 °C was successfully achieved in a completely open environment without minimizing the parasitic conduction and convection from the ambient. Prominent PSDRC phenomena could even be observed in such an open environment on very cloudy days, which generally compromise the RC. A much more prominent subambient cooling depression of 10.0 °C was observed when a wind shield was employed to minimize the convection. With suppression of convection, the subambient daytime cooling effect on cloudy days was even more noticeable than that occurred on clear sunny days. The subambient cooling effect was still very remarkable even on clear sunny days in the winter. The average cooling power measured on a clear sunny day was 154.8 ± 9.7 W/m2, corresponding to an average solar irradiance of 680 ± 90 W/m2 with a peak value of ∼820 W/m2. Both the subambient RC effect and the cooling power measured under real weather conditions using the radiative cooler agreed excellently with the theoretical prediction, sufficiently demonstrating the great innovation, validity, and effectiveness of the device.
Effect of succinonitrile on ion transport in PEO-based lithium-ion battery electrolytes
Authors: Mohapatra Sipra , Sharma Shubham , Sriperumbuduru Aman , Varanasi Srinivasa Rao , Mogurampelly Santosh
Published: May 2022

We report the ion transport mechanisms in succinonitrile (SN) loaded solid polymer electrolytes containing polyethylene oxide (PEO) and dissolved lithium bis(trifluoromethane)sulphonamide (LiTFSI) salt using molecular dynamics simulations. We investigated the effect of temperature and loading of SN on ion transport and relaxation phenomenon in PEO-LiTFSI electrolytes. It is observed that SN increases the ionic diffusivities in PEO-based solid polymer electrolytes and makes them suitable for battery applications. Interestingly, the diffusion coefficient of TFSI ions is an order of magnitude higher than the diffusion coefficient of lithium ions across the range of temperatures and loadings investigated. By analyzing different relaxation timescales and examining the underlying transport mechanisms in SN-loaded systems, we find that the diffusivity of TFSI ions correlates excellently with the Li-TFSI ion-pair relaxation timescales. In contrast, our simulations predict distinct transport mechanisms for Li-ions in SN-loaded PEO-LiTFSI electrolytes. Explicitly, the diffusivity of lithium ions cannot be uniquely determined by the ion-pair relaxation timescales but additionally depends on the polymer segmental dynamics. On the other hand, the SN loading induced diffusion coefficient at a given temperature does not correlate with either the ion-pair relaxation timescales or the polymer segmental relaxation timescales.
Pressure-induced reemergence of superconductivity in BaIr2Ge7 and Ba3Ir4Ge16 with cage structures
Authors: Pei Cuiying , Ying Tianping , Zhao Yi , Gao Lingling , Cao Weizheng , Li Changhua , Hosono Hideo , Qi Yanpeng
Published: May 2022

Clathrate-like or caged compounds have attracted great interest owing to their structural flexibility, as well as their fertile physical properties. Here, we report the pressure-induced reemergence of superconductivity in BaIr2Ge7 and Ba3Ir4Ge16, two new caged superconductors with two-dimensional building blocks of cage structures. After suppression of the ambient-pressure superconducting (SC-I) states, new superconducting (SC-II) states emerge unexpectedly, with Tc increased to a maximum of 4.4 and 4.0 K for BaIr2Ge7 and Ba3Ir4Ge16, respectively. Combined with high-pressure synchrotron x-ray diffraction and Raman measurements, we propose that the reemergence of superconductivity in these caged superconductors can be ascribed to a pressure-induced phonon softening linked to cage shrinkage.
Mg-doping and free-hole properties of hot-wall MOCVD GaN
Authors: Papamichail A. , Kakanakova-Georgieva A. , Sveinbjörnsson E. Ö. , Persson A. R. , Hult B. , Rorsman N. , Stanishev V. , Le S. P. , Persson P. O. Å. , Nawaz M. , Chen J. T. , Paskov P. P. , Darakchieva V.
Published: May 2022

The hot-wall metal-organic chemical vapor deposition (MOCVD), previously shown to enable superior III-nitride material quality and high performance devices, has been explored for Mg doping of GaN. We have investigated the Mg incorporation in a wide doping range (2.45×1018 cm−3 up to 1.10×1020 cm−3) and demonstrate GaN:Mg with low background impurity concentrations under optimized growth conditions. Dopant and impurity levels are discussed in view of Ga supersaturation, which provides a unified concept to explain the complexity of growth conditions impact on Mg acceptor incorporation and compensation. The results are analyzed in relation to the extended defects, revealed by scanning transmission electron microscopy, x-ray diffraction, and surface morphology, and in correlation with the electrical properties obtained by Hall effect and capacitance–voltage (C–V) measurements. This allows to establish a comprehensive picture of GaN:Mg growth by hot-wall MOCVD providing guidance for growth parameters optimization depending on the targeted application. We show that substantially lower H concentration as compared to Mg acceptors can be achieved in GaN:Mg without any in situ or post-growth annealing resulting in p-type conductivity in as-grown material. State-of-the-art p-GaN layers with a low resistivity and a high free-hole density (0.77 Ω cm and 8.4×1017 cm−3, respectively) are obtained after post-growth annealing demonstrating the viability of hot-wall MOCVD for growth of power electronic device structures.
Detection of the orbital angular momentum state of light using sinusoidally shaped phase grating
Authors: Dezfouli Ali Mardan , Abramović Denis , Rakić Mario , Skenderović Hrvoje
Published: May 2022

We demonstrate a method based on a unique sinusoidally shaped phased grating for efficient and nearly alignment free detection of both signs and modulus of the orbital angular momentum (OAM) of light. OAM detection efficiency is almost the same over the whole grating area. The capability and robustness of this method are demonstrated by detection of optical vortices with OAM topological charge up to 150 using a reflective phase-only liquid crystal on a silicon spatial light modulator.
Vector optical field manipulation via structural functional materials: Tutorial
Authors: Luo Xiangang , Pu Mingbo , Zhang Fei , Xu Mingfeng , Guo Yinghui , Li Xiong , Ma Xiaoliang
Published: May 2022

Vector optical field (VOF) manipulation greatly extended the boundaries of traditional scalar optics over the past decades. Meanwhile, the newly emerging techniques enabled by structural functional optical materials have driven the research domain into the subwavelength regime, where abundant new physical phenomena and technologies have been discovered and exploited for practical applications. In this Tutorial, we outline the basic principles, methodologies, and applications of VOF via structural functional materials. Among various technical routes, we focus on the metasurface-based approaches, which show obvious advantages regarding the design flexibility, the compactness of systems, and the overall performances. Both forward and inverse design methods based on the rigorous solution of Maxwell's equations are presented, which provide a valuable basis for future researchers. Finally, we discuss the generalized optical laws and conventions based on VOF manipulation. The applications in optical imaging, communications, precision measurement, laser fabrication, etc. are highlighted.
Instability of separated shear layer around levitated freestream-aligned circular cylinder
Authors: Yokota Sho , Asai Keisuke , Nonomura Taku
Published: May 2022

In the present study, characteristics of a shear layer around a freestream-aligned circular cylinder and the relationship between the shear layer motion and the aerodynamic force were investigated under supportless condition. A 0.3-m magnetic suspension and balance system was employed, and experiments were conducted without a mechanical supporting device. Velocity fields were measured using particle image velocimetry with a sufficient temporal and spatial resolution, and high-frequency velocity fluctuations caused by small Kelvin–Helmholtz (KH) vortices were captured. The power spectral densities of velocity fluctuations represent phenomena such as KH vortex convection, vortex pairing, and convection of multiple vortices. Furthermore, fluctuations of the shear layer position were investigated. The results illustrate that the dominant frequency of the shear layer position is lower than the frequency of the velocity, and it shows good agreement with the characteristic frequency of lift force fluctuations. The present results together with the report in the previous study illustrate that the pressure fluctuations are considered to drive both fluctuations of the shear layer position and lateral aerodynamic force.
Tracing the origin of heterogeneities in the local structure and very sluggish dynamics of [Cho][Gly] ionic liquid confined between rutile and graphite slit nanopores: A MD study
Authors: Khorrami Farzad , Kowsari Mohammad H.
Published: May 2022

Atomistic-level understanding of the interfacial behavior of ionic liquids (ILs) confined in slit-like nanopores is of both fundamental and practical interest. Molecular dynamics (MD) is an efficient and robust approach to characterize the properties of confined systems in contrast with some limitations in direct experimental measurements at low-dimensions. In this research, MD simulations are used to study the biocompatible IL cholinium glycinate, [Cho][Gly], confined between two parallel plates of rutile or graphite, with the separation distance of 24 Å along the z-direction. As expected, both the microscopic local structure and dynamical behavior of the confined IL are very heterogeneous and depend effectively on the position of the ions to the pore walls. The ion z-density profile is used for segmentation of the inter-wall space into a central region and two outer layers. The behavior of ions in the central region is very similar to the bulk IL, while the behavior of the arranged ionic layers adjacent to the pore walls shows the clear deviation from the bulk IL due to confinement. In general, the confined IL shows a “solid-like” dynamics at T = 353 K, especially in the outer layers near the walls as well as in the z-direction. The presence of the “IL-rutile wall” electrostatic interaction and hydrogen bonding (H-bonding) causes a significant difference in the local structure and very sluggish dynamics of the IL adjacent to the rutile walls vs the graphite walls. Simulation reveals a significant decrease in the average number of key cation–anion H-bonds at the outer layers relative to the central regions of both confined systems. The recognized [Cho]+⋯[Gly]−⋯[Cho]+ bridge structure at the central region is lost in the vicinity of the rutile walls due to inaccessibility of the hydroxyl hydrogen atom, which forms a stable H-bond with the rutile oxygen site. However, another unprecedented [Gly]− bridge is confirmed and preserved near the graphite walls, and [Cho]+ cations prefer to stay parallel to the wall surface to form the van der Waals dispersion interactions with the uncharged graphite walls.
N-Heterocycles via oxidative intramolecular cyclization
Authors: Shainyan B. A.
Published: May 2022

This review highlights two principal strategies of the last years (since 2015) for the design of various N-heterocycles including those containing O, S, Si, Se, Te heteroatoms via oxidative intramolecular cyclization using different catalysts, oxidants and reaction conditions.
 The bibliography includes 132 references.
Speech perception and production abilities in a group of Italian preschoolers aged 72–78 months
Authors: Lucarini Gaia , Bovo Roberto , Galatà Vincenzo , Pinton Alessandra , Zmarich Claudio
Published: May 2022

Objectives

The present work aims to contribute to the debate on the relationship between discrimination and production abilities in older pre-school-aged children and to fill a gap in the literature by providing evidence about this relationship in typically developing children speaking Italian, a language that is under-investigated.

Methods

Two novel tests, an AX ‘same/different’ phonological discrimination test and a phonetic test, were administered to a sample of Italian pre-school children aged 72–78 months. Discrimination was tested at the feature and the syllable levels. Production was analyzed for consonant repertoire and the presence of phonological processes, such as devoicing or consonant cluster reduction.

Results

In the AX test, significantly worse performance was found for syllables than for individual features. However, in production, no significant difference was found among phonological processes. No significant correlations were found between children’s performance in the two tests.

Conclusion

The current data suggest that children’s discrimination and production abilities for speech are still developing after age 6. There is no complete overlap between what children produce and what they discriminate. The implications of these findings for theories of language development are discussed.
Enhanced electrical properties and conduction mechanism of A-site rare-earth Nd-substituted CaBi2Nb2O9
Authors: Chen Juan-Nan , Wang Qian , Lu Hong-Ting , Zhao Xian , Wang Chun-Ming
Published: May 2022

Calcium bismuth niobate (CaBi2Nb2O9, CBN) is considered to be one of the most promising high-temperature (HT) piezoelectric materials owing to its high Curie temperature of ∼940 °C, however, its low electrical resistance and poor piezoelectric properties at elevated temperatures limit its applications at high temperatures. In this work, we report the significantly enhanced dc electrical resistivity and piezoelectric performance of CBN ceramics through rare-earth Nd-substitution. The crystal structure, microstructure, and dielectric, electrical, ferroelectric and piezoelectric properties of Nd-modified CBN with nominal compositions of Ca1−x
Nd
x
Bi2Nb2O9 (CBN-100xNd) have been investigated in detail. The results indicate that the substitutions of Nd3+ ions for Ca2+ ions increase the piezoelectric properties, and reduce the dielectric loss tanδ at high temperatures. The dc and ac conduction mechanisms indicate that the conduction mechanism is closely related to oxygen vacancies that are reduced through the donor substitutions of Nd3+ for Ca2+, thereby resulting in a significant improvement in the dc electrical resistivity. The optimal composition of CBN-3Nd exhibits a high piezoelectric constant d
33 of 13.5 pC N−1, and a high Curie temperature T
c of 948 °C. More importantly, the CBN-3Nd exhibits good thermal stability of the electrical properties (ρ= 2.6 × 107 Ω cm at 500 °C and 1.8 × 106 Ω cm at 600 °C, k
p = 6.1%–6.2% at RT ∼ 500 °C), which demonstrates that the Nd-modified CBN ceramics are promising piezoelectric materials for use in HT piezoelectric sensors.
Morse potential specific bond volume: a simple formula with applications to dimers and soft–hard slab slider
Authors: Al-Raeei Marwan
Published: May 2022

Morse potential interaction is an important type of the vibrational potentials, especially, in the quantum mechanics which is used for the describing of general vibrational cases rather than the harmonic one. Morse potential has three fitting parameters, the depth of the Morse interaction, the distance of equilibrium bond and the range parameter which determines the range of the well. The Morse interaction specific bond volume is a three dimensional image of the bond length in its molar case, and this specific volume is the generalisation in three dimensions. In this study, the integral equation theory of the simple fluids has been applied for deriving a novel formula of the specific bond volume for Morse potential based on one of the approaches in the theory and based on the boundary conditions. We find that the specific bond volume of Morse potential depends on the absolute temperature via logarithmic function and square root function, besides, the specific bond volume of Morse potential decreases when the temperature decreases for different values of the molar volume and for different values of the depth of Morse well. In addition to that, the specific bond volume of Morse potential increases when the depth of the well decreases for different temperature values. Also, it is found from the formula which we derive that the specific bond volume of Morse potential increases via linear function with the molar volume of the system for different values of temperatures. We apply the formula of the specific bond volume of Morse potential for finding this specific volume for two molecules of the hydrogen halogens, which are the hydrogen chloride, and hydrogen fluoride. We find that the specific bond volume of the hydrogen chloride is greater than the one of the hydrogen fluoride. Also, we apply the formula for the two simple molecules gases which are the hydrogen molecules, and the nitrogen molecules. Besides, we apply the formula for the slab–slider system in two cases: hard and soft materials, and we concluded that the changes of the specific bond volume of the soft materials is faster than the hard materials. We believe that the formula which is found of the specific bond volume of Morse potential is general and can be applied for multiple materials.
Molecular dynamics study of fatigue behavior of nickel single-crystal under cyclic shear deformation and hyper-gravity condition
Authors: Xiao Yudi , Deng Xiaojuan , Ma Yiwu , Huang Bowen , Hu Wangyu
Published: May 2022

Dynamic mechanical properties play an essential role in governing the intrinsic fatigue behavior of superalloys. In this work, [001](010), [110](−110), and [101](010) pre-existing center cracks model of nickel single crystals under increasing cyclic shear deformations were studied by molecular dynamics simulations. More importantly, we introduced three hyper-gravity forces, i.e. 3 × 1012 g, 4 × 1012 g, and 5 × 1012 g, during the fatigue deformation to simulate the high-speed rotation of the blade. The stress intensity factor for the first dislocation nucleation indicates that the critical stress is strongly dependent on the hyper-gravity intensities and temperatures. The fatigue life decreased rapidly with the elevated hyper-gravity strength. Moreover, the [001](010) crack propagation shows a brittle-to-ductile transition at temperatures below 300 K and is suppressed at high temperatures. The crack length in the relation to hyper-gravity intensities is discussed and shows anisotropy along the direction of hyper-gravity. No crack propagation is observed in [110](−110) and [101](010) central crack models.
Front-like expansion and arrest of programmed cell death in brown banana spots
Authors: Steinbock Oliver , Wang Qingpu , Knoll Pamela
Published: May 2022

The spot patterns on bananas are a striking case of biological pattern formation and—as a qualitative ripeness indicator—linked to 50 million tons of wasted food per year. Ripening bananas develop these senescent spots as phenolic compounds are enzymatically oxidized and cellular integrity is lost. We characterize the dynamics of the spot expansion and their nucleation rates based on time-lapse movies. Spots nucleate for about 2 days yielding a typical density of 8 spots/cm2. The expansion is initially diffusion controlled and the effective diffusion coefficient decreases with nucleation time from 1.3 to 0.4 mm2 d−1. During and after expansion, the browning fronts maintain a steep and constant intensity gradient. We quantitatively reproduce these features by a reaction–diffusion model that considers the local oxygen concentration and browning degree of the peel. All model parameters are based on measurements and front stalling is explained by decreasing oxygen levels in the nucleation sites.
A 40 Gbps optical transceiver for particle physics experiments
Authors: Deng B. , Huang X. , Sun H. , Chao C.-P. , Chen S.-W. , Gong D. , Hou S. , Huang G. , Li C.-Y. , Liu C. , Liu T. , Sun Q. , Ye J. , Zhang L. , Zhang W.
Published: May 2022

We present the design and the test results of a quad-channel optical transceiver module (QTRx) possibly for future particle physics experiments. The transmitters of QTRx, each at 10 Gbps, are based on a Quad-channel VCSEL Diode array Driver (QLDD) and 1 × 4 VCSEL array. The receivers of QTRx, with data rates of 2.56 Gbps or 10 Gbps per channel, are based on a Quad-channel Trans-Impedance and limiting Amplifier (QTIA) and 1 × 4 photodiode array of GaAs or InGaAs. QTRx is 20 mm × 10 mm × 5 mm and couples to an MT fiber connector. Test results indicate that QTRx achieves the design goals with a power consumption of 124 mW per transmitter channel at 10 Gbps and 120 mW at 2.56 Gbps per receiver channel with an on-chip charge pump. The sensitivities of QTIA are −17 dBm at 2.56 Gbps and −8 dBm at 10 Gbps, respectively. Further improvements with a gold-finger interface and a more compact optical lens are being designed.
A novel differential time-of-flight algorithm for high-precision ultrasonic gas flow measurement
Authors: Li L. , Hu Y. , Dong J. , Wu Q. , Hu T. , Zhu F.
Published: May 2022

The use of ultrasonic gas flow meters has expanded in industrial and household fields owing to their unique advantages. The transit-time method is applied to measure the gas flow rate by determining the absolute time-of-flight (TOF). However, it is inevitable that there is a contradiction between long time scale and high time precision of absolute TOF. In this paper, a novel differential TOF (ΔT) algorithm is proposed for high-precision ultrasonic gas flow measurements. The experimental results proved that ΔT plays a decisive role in the actual flow rate calculation. Therefore, when the absolute TOF is obtained, furthermore, the high-precision ΔT is calculated by the cross-power spectrum method separately. The two echo signals are aligned and compared to obtain ΔT, instead of subtracting the absolute TOFs. Either of the two echo signals is the reference signal of each other, which also avoids the problem of finding reference signals. The results of the calibration experiment indicate that the algorithm improves the stability of zero flow drift under static conditions and the accuracy of the dynamic flow rates. The algorithm allows the adjustment of parameters to be applied to pipes of different diameters. The parameters of the algorithm can be adjusted for application to ultrasonic flow metering systems of different diameters.
Development of a compact torus injector system for central fuelling technology of EAST
Authors: Zhao Z.H. , Lan T. , Kong D.F. , Ye Y. , Zhang S.B. , Zhuang G. , Zhang X.H. , Hu G.H. , Chen C. , Wu J. , Zhang S. , Qi M.B. , Li C.H. , Yang X.M. , Nie L.Y. , Wen F. , Zi P.F. , Li L. , Meng F.W. , Li B. , Dong Q.L. , Huang Y.Q.
Published: May 2022

In this paper, a compact torus (CT) injector system is
designed for experimental advanced superconducting tokamak
(EAST). The injector system consists of a coaxial electrode and four
pulsed power systems and generates self-organized CT with high
density and velocity. In addition, the performance of EAST-CTI is
evaluated using a series of diagnostics systems. The experimental
results show that the velocity, electron density, and number of
particles of the CT are 56.0 km/s,
8.73 × 1020 m-3, and 2.4 × 1018,
respectively. The detailed description and experimental results are
presented in this paper.
The design and development of DAB DC- DC converter for HF MRI superconducting magnet power supply
Authors: Dai T. , Wang F. , Xue S. , Gao P. , Zhang Z. , Qin J. , Zhou C. , Li J.
Published: May 2022

According to the design requirements of high-field (HF)
magnetic resonance imaging (MRI) superconducting magnet power
supply, the bidirectional dual-active-bridge (DAB) DC-DC converter
is analyzed, designed and developed. This paper presents the overall
topology design of the middle stage DAB converter. In turn, the
single channel DAB converter is designed and analyzed in detail,
including magnetic component design, control system design and power
device selection. The results show that the designed converter can
meet the system requirements.
A methacrylated hyaluronic acid network reinforced Pluronic F-127 gel for treatment of bacterial keratitis
Authors: Wang Anyang , Dong Lina , Guo Zhongwei , Sun Wei , Mi Shengli
Published: May 2022

In this study, we developed a novel in situ thermoresponsive gel by introducing crosslinked methacrylated hyaluronic acid (HA-MA) networks into Pluronic F-127 (PF-127) gel (HP gel) to achieve sustained levofloxacin (LFX) delivery in bacterial keratitis treatment. The interactions between PF-127 molecules and HA-MA networks were studied by scanning electron microscopy, rheology, dynamic light scattering, differential scanning calorimetry, and small angle x-ray scattering. The results showed that the HP gel exhibited a higher critical gelling temperature and lower viscosity than the PF-127 gel (P gel), and could form a uniform thin layer on the ocular surface. Moreover, the drug release profile and gel dissolution rate revealed that the HA-MA network could retard the diffusion and dissolution of drug molecules and prolong the drug release time, which corresponded to an enhanced antibacterial ability of the HP-LFX gel. Furthermore, the HP gel exhibited low cytotoxicity to human corneal epithelial cells. Finally, an in vivo pharmacodynamic study was conducted with rabbit keratitis models. An improved treatment efficacy was observed after application of the HP-LFX gels. This study highlights the potential of HP gels in ophthalmic drug delivery.
Screening of Phytochemicals from the Ethanolic Extracts of Gnetum gnemon, Gnetum latifolium and Cynometra malaccensis of Kuala Keniam, Pahang
Authors: Ahmat N , Kamarozaman A S , Johari M S M , Abas F , Mohamad S A S , Yunoh S M M
Published: May 2022

The diversity of plants has led to various findings in the medicinal world. The abundance of bioactive compounds existing in the plant is the main factor contributing to its application in pharmaceutical industries. Gnetum gnemon, Gnetum latifolium and Cynometra malaccensis were collected from the forest area, Stesen Penyelidikan UiTM-Perhilitan, Kuala Keniam, Taman Negara, Pahang. This project focussed on profiling the bioactive constituent through phytochemical screening via Shinoda, Mayer, saponin, tannin, and terpenoid tests from the ethanolic extract of stem bark, stem, leaves and twigs of the three species. The results displayed that all plant parts showed the presence of flavonoids, terpenes and tannins. These compounds might contribute to the good properties of the plants.
Enhancing soil chemical properties at plantation riparian buffer zone using leguminous cover crops: A review
Authors: Suliman Nurul Shazuwani , Kassim Nur Qursyna Boll
Published: May 2022

The construction of a reserved area known as riparian buffer zone (RBZ) in oil palm plantation is one of the conservation measures that helps to protect the nearest water sources from negative impact of adjacent land uses. Most of the plantation planted different types of leguminous cover crops (LCCs) at the RBZ area, considering the benefits and economical planting cost. However, little is known on the changes of soil properties sited in the RBZ which has been planted with different LCCs. As such, this paper intends to review the enhancement of soil chemical properties, specifically the soil pH, soil macronutrients and soil micronutrients at RBZ planted with different LCCs. The review encompasses the most common LCCs planted which are limited to Mucuna bracteate, Pueraria phaseoloides, Clitoria ternate, Calopogonium mucuinodes and Centrosema pubescens. The effects of these LCCs on abovementioned soil properties were discussed and the issues on fertilizer run-off as well as the impact on the soil chemical properties at RBZ is critically reviewed. Findings showed that the planting of LCCs demonstrate a positive uptake of the run-off nutrients from adjacent land use, reflected by the amount of nutrients fixed by the LCCs as well as nutrients left in the soil. The findings also reveal that there is evidence on the enhancement of soil fertility in RBZ, due to the decomposition process followed by nutrient recycling of LCCs residues. This review suggested that the planting of LCCs in RBZ can enhance the soil chemical properties, reducing the fertilizer run-off through efficient nutrient uptake and act as the buffer zone to conserve the nearest water sources, leading to the sustainable environment in oil palm plantation.
Preliminary Study on the Distribution and Diversity of Diptera at Tuba Island Reserve Forest, Langkawi Malaysia
Authors: Nizam N A , Mohd Najib C N I I , Yusof N N Md. , Mohammad Naser N B , Mohd Hatta S K
Published: May 2022

Insects, the ecologically important organisms, contribute most to the world’s biodiversity. A study on distribution to diversity of order Diptera was conducted in a selected area of Tuba Island Forest Reserve, Langkawi from 17th September to 21st September 2020 using Malaise traps. Three study sites which were forest fringe, middle forest and inner forest were chosen. A total of 5450 individuals of Diptera belonging to 18 families and 27 morphospecies were collected in this study. Diptera samples were highly abundant in the forest fringe with Mycetophilidae as the most abundant family recorded, while the least abundant family was Drosophilidae. The Shannon-Weiner Diversity Index (H’) showed that the forest fringe had the highest diversity value (H’=2.05), followed by the inner forest (H’=0.67) and middle forest (H’=0.45). The highest Evenness Index (E’) value was recorded from the inner forest with E’=0.66 while the highest value for Margalef Richness Index (R’) was from the forest fringe which was 1.91. The Kruskal-Wallis H test conducted indicates that there was a significant difference in the distribution of Dipteran across the three locations of the forest with P<0.05. Overall, this study suggested that the diversity of order Diptera was higher in the forest fringe compared to the middle and the inner forest. This study is important as it is helpful for future study of Diptera species in Tuba Island as well as for conservation measures in the island ecosystem.
Relationship between Particulate Matter (PM2.5) Concentration and Aerosol Optical Depth (AOD) throughout Peninsular Malaysia
Authors: Talib Noorfatekah , Sa’aidi Nur Amira Mohd , Narashid Rohayu Haron , Zaki Nurul Ain Mohd , Saad Nurhafiza Md , Abdullah Suzanah , Mohd Fazly Amri
Published: May 2022

A particular matter (PM2.5) is a small particle in the air that reduces visibility and causes air to fade when raised. It is one of the parameters that contribute to air pollution. There are a few causes of air pollution. It can appear in solid and liquid particles and certain gases that are suspended in the air. Consequently, pollution can significantly and negatively impact human health. This study aimed to explore the relationship between concentrations of PM2.5 and aerosol optical depth (AOD) throughout Peninsular Malaysia using the GIS approach. The tabular data of PM2.5 was acquired from the Department of Environment and overlaid with the MODIS satellite image. A correlation test was performed using QGIS software using Inverse Distance Weighting (IDW) technique. Then, by using the Air Pollution Index data and the value of Aerosol Optical Depth, this study can identify the values that influence the pollutants by studying the relationship between PM2.5 and AOD using MODIS satellite images. The linear regression of PM2.5 concentration with the MODIS AOD has shown significant differences. This study aligns with the eleven Sustainable Development Goals which are focused on sustainable cities and communities, to reduce the adverse environmental impact of cities per capita, especially the air quality such as fine particulate matter (PM2.5 and PM10) in cities.
Impact Of Movement Control Order (MCO) Of Covid-19 Pandemic on Aerosol Optical Depth Over Peninsular Malaysia
Authors: Alias Ahmad Fadhilah Bin , Salim Pauziyah Binti Mohammad , Latif Zulkiflee Abdul
Published: May 2022

Recently in 2020, the spread of the Virus COVID-19 leads the government of Malaysia to enforce for a Movement Control Order (MCO) in order to curb the pendamic. Thus, this study aims to analyse aerosol optical depth from MODIS aerosol product over Peninsular Malaysia before and during the MCO. Data before MCO shows a higher AOD concentration in major part of the eastern coast of the peninsular. This might be due mostly to the long range transport of agricultural or biomass burning season that occur in the Mekong sub-region area as reported by ASEAN Specialised Metrological Centre brought to eastern part of the Peninsular with the Northeast Monsoon wind. Both data before and during MCO managed to capture high AOD concentrations in the Greater Kuala Lumpur as well as area southern of the state of Perak confirming that the resuspension of urban, dust, and open biomass burning aerosols from local sources are dominant in this area. As of quantification of the AOD concentration, The highest reduction was at Temerloh, with -40.3% (0.67-0.4), while the lowest reduction was at Bandaraya Melaka with -4.6% (0.43-0.41). Highest increment of AOD during was detected in Sri Manjung, with value of 56.1% and Kulim Hightech as well as Alor Setar not far behind with, 55.1% and 54.8% respectively. It can be clearly seen that Northern and Central Region contribute to the increase of AOD while the Eastern Region contributes to the reduction of AOD for the study area during this MCO. The overall total AOD average is 0.413 before the MCO and 0.432 during the MCO giving a total increment of 4.6%.
Effects of Cr content and electromagnetic stirring on the phase separation of Cu-Cr alloy
Authors: Yang Zhihao , Jin Qinglin
Published: May 2022

The Cu-Cr immiscible alloys were prepared by arc melting. The effects of Cr addition and electromagnetic stirring on the phase separation, microstructure were examined. The results show that serious phase segregation occurs at the center of the sample with increasing Cr contents, forming a sandwich like structure. The shape of the primary Cr transforms from fine dendrite to more developed dendrite. Thermodynamic analysis indicates that Cr addition increases the driving force for the liquid phase separation. The electromagnetic stirring can facilitate elative motion between the Cr droplets and the melts, and thus intensify the segregation phenomenon. With Cr additions, the hardness in non-segregated area shows only slight increase, and in Cr segregated area shows a significant increase. While the electrical conductivity shows only slight decrease with increasing Cr content.
The effect of nitrogen concentration on the properties of N-DLC prepared by helicon wave plasma chemical vapor deposition
Authors: YANG Yan , HUANG Tianyuan , LI Maoyang , YU Yaowei , HUANG Jianjun , YU Bin , WU Xuemei , JI Peiyu
Published: May 2022

Nitrogen-doped diamond-like carbon (N-DLC) films were synthesized by helicon wave plasma chemical vapor deposition (HWP-CVD). The mechanism of the plasma influence on the N-DLC structure and properties was revealed by the diagnosis of plasma. The effects of nitrogen doping on the mechanical and hydrophobicity properties of DLC films were studied. The change in the ratio of precursor gas flow reduces the concentration of film-forming groups, resulting in a decrease of growth rate with increasing nitrogen flow rate. The morphology and structure of N-DLC films were characterized by scanning probe microscopy, Raman spectroscopy, and X-ray photoemission spectroscopy. The mechanical properties and wettability of N-DLC were analyzed by an ultra-micro hardness tester and JC2000DM system. The results show that the content ratio of N+ and

N

2

+

is positively correlated with the mechanical properties and wettability of N-DLC films. The enhancement hardness and elastic modulus of N-DLC are attributed to the increase in sp3 carbon–nitrogen bond content in the film, reaching 26.5 GPa and 160 GPa respectively. Water contact measurement shows that the increase in the nitrogen-bond structure in N-DLC gives the film excellent hydrophobic properties, and the optimal water contact angle reaches 111.2°. It is shown that HWP technology has unique advantages in the modulation of functional nanomaterials.
Contribution of the Sn 5s state to the SnS valence band: direct observation via ARPES measurements
Authors: Suzuki Issei , Kawanishi Sakiko , Tanaka Kiyohisa , Omata Takahisa , Tanaka Shin-ichiro
Published: May 2022

Tin sulfide (SnS) is a compound semiconductor that has been studied for a wide range of applications, including solar cells and thermoelectric materials. In this study, the electronic structure of the SnS valence band, which is important for such applications, was investigated via angle-resolved photoelectron spectroscopy with two different excitation energies in the extreme ultraviolet region (21 and 60 eV). The contribution of the Sn 5s state to the SnS valence band was determined in relation to the k-vector by utilizing the fact that the cross section of Sn 5s state varies significantly compared to those of other states in the extreme ultraviolet region. The experimental results demonstrate that the Sn 5s state significantly contributed to the k-vector around the valence band maximum (VBM) and second VBM (VBM1).
Determining optimal parameters using Taguchi’s design of experiments (DOE) for improving the quality of biogas generation process
Authors: Kanakavalli Prakash Babu , More Satish R
Published: May 2022

The use of an anaerobic process of biogas production depends on various parameters. Increasing the methane (CH4) production percentage is a critical task in an anaerobic process. In the present investigation, the role of the four most common process parameters are temperature, pH value, solid concentration, and C/N ratio optimized for two responses i.e. biogas production and higher methane percentage. A Taguchi Design of Experiment (DOE) methodology was used to investigate and analyze the effects of different parameters using an L9 orthogonal array. The investigation results for both responses showed that solid concentration had a higher contribution of 65.37% and 73.37% for biogas production and methane percentage respectively. The second rank responsible parameter for both the responses is pH having the same contribution of 18%. the initial pH and rotation speed of the process was the most effective parameters for comparison with others. While the other factors’ temperature and C/N ratio contribution are 15.54% and 0.13% for biogas production and 3.48% and 4.25% for methane percentage. Biogas production and methane percentage model found with correlation percentage (r2) 0.98 and 0.92 respectively which is agreeable. The confirmation test results with Taguchi’s model show errors of 7.46% and 2.43% for biogas and methane production percentages respectively.
Local invariants of minimal generic curves on rational surfaces
Authors: Cogolludo-Agustín José , László Tamás , Martín-Morales Jorge , Némethi András
Published: May 2022

Let

(
C
,
0
)

(C,0)

be a reduced curve germ in a normal surface singularity

(
X
,
0
)

(X,0)

. The main goal is to recover the delta invariant

δ
(
C
)

\delta (C)

of the abstract curve

(
C
,
0
)

(C,0)

from the topology of the embedding

(
C
,
0
)
⊂
(
X
,
0
)

(C,0)\subset (X,0)

. We give explicit formulae whenever

(
C
,
0
)

(C,0)

is minimal generic and

(
X
,
0
)

(X,0)

is rational (as a continuation of some previous papers by the authors).

Additionally, in this case, we prove that if

(
X
,
0
)

(X,0)

is a quotient singularity, then

δ
(
C
)

\delta (C)

only admits the values

r
−
1

r-1

or

r
r

, where

r
r

is the number or irreducible components of

(
C
,
0
)

(C,0)

. (

δ
(
C
)
=
r
−
1

\delta (C)=r-1

realizes the extremal lower bound, valid only for ‘ordinary

r
r

–tuples’.)
Scaled lattice rules for integration on ℝ^{𝕕} achieving higher-order convergence with error analysis in terms of orthogonal projections onto periodic spaces
Authors: Nuyens Dirk , Suzuki Yuya
Published: May 2022

We introduce a new method to approximate integrals∫Rdf(x)dx\int _{\mathbb {R}^d} f(\boldsymbol {x}) \,\mathrm {d}\boldsymbol {x}which simply scales lattice rules from the unit cube[0,1]d[0,1]^dto properly sized boxes onRd\mathbb {R}^d, hereby achieving higher-order convergence that matches the smoothness of the integrand functionffin a certain Sobolev space of dominating mixed smoothness. Our method only assumes that we can evaluate the integrand functionffand does not assume a particular density nor the ability to sample from it. In particular, for the theoretical analysis we show a new result that the method of adding Bernoulli polynomials to a function to make it “periodic” on a box without changing its integral value over the box is equivalent to an orthogonal projection from a well chosen Sobolev space of dominating mixed smoothness to an associated periodic Sobolev space of the same dominating mixed smoothness, which we call a Korobov space. We note that the Bernoulli polynomial method is often not used because of its excessive computational complexity and also here we only make use of it in our theoretical analysis. We show that our new method of applying scaled lattice rules to increasing boxes can be interpreted as orthogonal projections with decreasing projection error. Such a method would not work on the unit cube since then the committed error caused by non-periodicity of the integrand would be constant, but for integration on the Euclidean space we can use the certain decay towards zero when the boxes grow. Hence we can bound the truncation error as well as the projection error and show higher-order convergence in applying scaled lattice rules for integration on Euclidean space. We illustrate our theoretical analysis by numerical experiments which confirm our findings.
Differences between perfect powers: The Lebesgue-Nagell equation
Authors: Bennett Michael , Siksek Samir
Published: May 2022

We develop a variety of new techniques to treat Diophantine equations of the shape

x
2

+
D
=

y
n

x^2+D =y^n

, based upon bounds for linear forms in

p
p

-adic and complex logarithms, the modularity of Galois representations attached to Frey-Hellegouarch elliptic curves, and machinery from Diophantine approximation. We use these to explicitly determine the set of all coprime integers

x
x

and

y
y

, and

n
≥
3

n \geq 3

, with the property that

y
n

>

x
2

y^n > x^2

and

x
2

−

y
n

x^2-y^n

has no prime divisor exceeding

11
11

.
A case for continuing statin medications in the intensive care unit: Reducing the risk for delirium
Authors: Navia Kyra L , Anthony Bridget K , Berlau Daniel J
Published: May 2022

Purpose

The objective of this review is to detail the utility of statin medications in the prevention and treatment of intensive care unit (ICU) delirium.

Delirium is a syndrome characterized by altered mental status, inattention, and disorganized thinking. It is particularly concerning in the ICU where specific risk factors are much more prevalent. Nonpharmacological therapy is the mainstay of treatment, aimed at increasing patient awareness; pharmacological therapies have also been explored with varying success. The utility of statin medications in this scenario has been investigated because of the numerous pleiotropic effects of these drugs. Although the benefits in terms of treating delirium are uncertain, statins may be good candidates for prevention. The peak anti-inflammatory effect of statins is delayed, so initiating a statin on admission will likely have little protective benefit, whereas continuation of a home regimen seems more likely to exert an effect.

Conclusion

Statin medications are very commonly used, and, while their role in treating delirium is unclear, continuation of these medications from a home regimen is reasonable to decrease the odds of delirium in the intensive care population.
Mosquito Control Workers in Malaysia: Is Lifetime Occupational Pesticide Exposure Associated With Poorer Neurobehavioral Performance?
Authors: Yusof Muhammad Zubir , Cherrie John W , Samsuddin Niza , Semple Sean
Published: May 2022

Background

Use of pesticides has been linked to neurobehavioral deficits among exposed workers. In Malaysia, organophosphate and pyrethroid pesticides are commonly used to control mosquito-borne diseases.

Objectives

This study aims to assess workers’ lifetime occupational pesticide exposure and examine the relationship with neurobehavioral health.

Methods

A cross-sectional study was conducted on 158 pesticide-exposed and 176 non-exposed workers. To collect historical exposure and job tasks, a questionnaire and an occupational history interview were used. Pesticide exposure was measured in a subgroup of workers via inhalation and skin contact. The total pesticide intake of each worker was assessed using inhalation and dermal exposure models. CANTAB® computerised neurobehavioral performance assessments were used.

Results

The participants’ mean age was 31 (8) years. Pirimiphos-methyl (median = 0.569 mg/m3, Interquartile range [IQR] = 0.151, 0.574) and permethrin (median = 0.136 mg/m3, IQR = 0.116, 0.157) had the highest measured personal inhalation concentrations during thermal spraying. The estimated total lifetime pesticide intake for exposed workers ranged from 0.006 g to 12800 g (median = 379 g and IQR = 131, 794 g). Dermal exposure was the predominant route of pesticide intake for all workers. Compared to controls, workers with high lifetime pesticide intake had lower Match to Sample Visual (adjusted B = −1.4, 95% Confidence Interval (CI) = −2.6, 0.1), Spatial Recognition Memory (adjusted B = −3.3, 95% CI = −5.8, 0.8), Spatial Span (SSP) (adjusted B = −0.6, 95% CI = −0.9, 0.3) scores. Workers with low pesticide intake performed worse than controls (adjusted B = −0.5, 95% CI = −0.8, −0.2) in the SSP test, but scored higher in the Motor Screening test (adjusted B = 0.9, 95% CI = 0.1, 1.6). Higher Paired Associates Learning test scores were observed among higher (adjusted B = 7.4, 95% CI = 2.3, 12.4) and lower (adjusted B = 8.1, 95% CI = 3, 13.2) pesticide intake groups. There was no significant difference between the Reaction Time and Pattern Recognition Memory tests with lifetime pesticide intake after adjusting for confounders.

Conclusion

Pesticide exposure has been linked to poorer neurobehavioral performance. As dermal exposure accounts for a major fraction of total intake, pesticide prevention should focus on limiting dermal exposure.