bluuebunny/crossref_metadata_2025_split huggingface dataset:
The potential of biomass waste in Malaysian palm oil industry: A case study of Boustead Plantation Berhad
Authors: Jafri N H S , Jimat D N , Azmin N F M , Sulaiman S , Nor Y A 
Published: November 2021

AbstractThe oil palm industry is known as the primary producer of biomass in Malaysia. The massive production of oil palm biomass has resulted in a significant waste disposal problem. This study aims to assess the potential of waste derived from oil palm plantations and processing mills to be transformed into value-added products for various applications. The study was conducted on three oil palm estates managed by Boustead Rimba Nilai Berhad using data on the generation rates of fresh fruit bunches (FFB), crude palm oil (CPO), and oil palm biomass waste from 2018 to 2020. The availability of FFB, CPO, empty fruit bunches (EFB) and excess fibers, and palm oil mill effluents (POME) in 2030 was predicted using a forecasting approach, with trend analysis as the tool of choice. From 2018 to 2020, the output of FFB, EFB and excess fibers, as well as POME grew by 16%, 14%, 23%, and 14% respectively. Based on trend analysis, the projection of FFB, CPO, EFB and excess fibers, and POME outputs in 2030 is expected to be 80%, 56%, 92%, and 56% respectively, which are greater than the figures recorded in 2020. The state of the palm oil industry in Malaysia was described in this study and also highlighted the potential of oil palm biomass in various industries and as a source of green energy. Oil palm biomass can be commercialized in a wide range of value-added products.
Effect of Stabilizers in the Synthesis of Silver Nanoparticles and Methylene Blue Oxidation
Authors: Amir Dzilal , Nasaruddin Ricca Rahman , Engliman Nurul Sakinah , Sulaiman Sarina , Mastuli Mohd Sufri 
Published: November 2021

Abstract
Metal nanocatalysts have received increasing attention in catalysis due to their higher reactivity and surface area-to-volume ratio at nano-size. Silver nanoparticle (AgNP) is among metal nanocatalysts that have been studied in various catalytic reactions (e.g., hydrogenation and oxidation). However, the high reactivity of AgNPs at nano-size caused instability and aggregation. Therefore, stabilizing molecules (or stabilizers) are always applied to maintain the nano size of AgNPs and prevent aggregation. Herein, the effects of different types and molar ratio of stabilizers-to-Ag precursor, to the synthesized AgNPs (i.e, size and concentration) were investigated. Two types of stabilizers, polyvinylpyrrolidone (PVP) and citrate were used in this study. The roles of stabilizers to the catalytic performance of synthesized AgNPs were then elucidated by using methylene blue oxidation as the model reaction. The UV-Vis absorption analyses showed that both stabilizers produced slightly different size and concentration of AgNPs based on the different wavelength and absorption intensity of the peak. We also found that the molar ratio of stabilizers-to-Ag precursor that produced better yield of AgNPs was 1:1 and 1:3 for PVP and citrate, respectively. Then, AgNPs stabilized by citrate was found having slightly higher catalytic activity in the methylene blue oxidation than AgNPs stabilized by PVP. This study provides insights to the roles of stabilizers for the synthesis of stable AgNPs with efficient catalytic reaction and can be used as guideline to other metal nanocatalysts.
Evaluating the potential of chitin extracted from shrimp shell wastes as support material of gold nanoclusters (AuNCs) for catalysis
Authors: Zakaria Nabila Azirah , Nasaruddin Ricca Rahman , Wan Nawawi Wan Mohd Fazli 
Published: November 2021

Abstract
Thiolate-protected gold nanoclusters (AuNCs) have been intensively studied due to their appealing physicochemical properties that can be used in various applications, especially catalysis. However, thiolate-protected AuNCs in a free suspension form, tend to aggregate during catalytic reaction due to the high surface reactivity of its ultrasmall size, hence, reducing the rate of their catalytic reaction. Their recovery and reusability are also difficult. Therefore, several support materials have been studied to immobilize the thiolate-protected AuNCs for a better recovery, reusability and stability in solution and during a catalytic reaction. Herein, chitin extracted from shrimp shell waste was used as support material for the immobilization of the AuNCs protected by p-mercaptobenzoic acid ligands, using deposition-precipitation method. The free chitin and chitin immobilized with thiolate-protected AuNCs (abbreviated as AuNCs/Chitin) were characterized using FTIR. The catalytic properties of the AuNCs/Chitin were then evaluated in the hydrogenation of 4-nitrophenol in solution as the model reaction. It was found that the chitin extracted from SSW has a good potential to be support materials of thiolate-protected AuNCs because the shorter reaction time it took (12 minutes) as compared to the reaction without catalyst (60 minutes) and it can be recovered and reused twice.
Nonlinear regression for analysis of the uptake of KMnO4 from aqueous solutions onto natural marl
Authors: Bouzeghaia E A , Hafsi S , Gherraf N 
Published: November 2021

Abstract
The present work aims to evaluate the performance of raw marl collected from the region of Oum El Bouaghi on the elimination of KMnO4 from aqueous solution. The adsorption capacities were studied using the batch technique as a function of pH, initial concentration and temperature. The maximum adsorption for KMnO4 was found to be 83.517% at pH 3.0. When the pH is low (pH<3.0), the uptake of KMnO4 occurs with an electrostatic attraction between the MnO4-ions and the surface proton groups, while at pH ≥3.0-8.0, the formation of complexes with the surface functional groups during the adsorption process and/or cation exchange are responsible for retention of Mn(II) ions onto marl. Experimental adsorption data were modeled with different nonlinear isotherms and kinetic models. Furthermore, statistical errors (SSE, SD, ARE, χ
2, R2 and R2
adj) were calculated to choose the suitable model. Langmuir isotherm was found to be best for fitting the experimental data. The calculated thermodynamic parameters indicated that adsorption process was physical, spontaneous and endothermic in nature. From this work, it was concluded that the natural marl can be used for effective elimination of KMnO4 from aqueous solution and wastewater.
Chemiresistive sensors based on Dodecyl benzene Sulfonic acid doped Polypyrrole and Reduced Graphene Oxide for nitrogen oxides
Authors: Guettiche Djamil , Mekki Ahmed , Zohra Tighilt Fatma , Ramdani Noureddine , Mahmoud Rachid 
Published: November 2021

Abstract
A new series of polypyrrole doped with n-dodecylbenzene sulphonic acid/reduced graphene oxide (PPy-DBSA/rGO) nanocomposite was electrodeposited on Indium tin oxide coated Polyethylene terephthalate (ITO/PET) flexible substrate by electrochemical route using the chronoamperometric technique. As-prepared for testing of chemiresistive properties against the detection of nitrogen dioxide (NO2) vapors at room temperature. The sensitivity and reactivity of the composite toward NO2 was evaluated. The recorded morphological and structural data confirmed that the PPy-DBSA/rGO forms a homogeneous nanocomposite. The optimal NO2 sensing properties have been revealed by the PPy-DBSA/rGO in terms of response (43%), response time (30.25 s), the detection limit (1ppm), and reproducibility. Furthermore, Results showed that the doped by sulfonic acid improved both the sensitivity and the reactivity of our produced nanocomposite toward NO2. Due to the strong interactions between the NO2 gas molecules and the rGO was dramatically enhanced the electronic properties of these nanocomposites. These striking characteristics of the newly developed nanocomposites make them very suitable to be used as NO2 gas sensor.
The trend towards a warmer and wetter climate observed in arid and semi-arid areas of northwest China from 1959 to 2019
Authors: Zheng Shijun , Zhang Bing , Peng Dailiang , Yu Le , Lin Binbin , Pan Yuhao , Xie Qiaoyun 
Published: November 2021

Abstract
The observed trend towards a warmer and wetter climate in northwest China is a controversial issue lacking sufficient scientific research. Based on monthly meteorological data from 201 weather stations in northwest China and surrounding regions from 1959 to 2019, we calculated potential evapotranspiration using Penman-Monteith (PM) equation. By analyzing the spatial–temporal variations in temperature and precipitation and by studying changing drought trends, we systematically explored the climate trends in northwest China over the past 60 years. Our findings include: (1) From 1959 to 2019, during the growing season, there was a significant upward trend in temperature across northwest China. The most obvious trend, ranged between 0.4 °C–0.6 °C per decade, was observed in northern Qinghai and northeastern Xinjiang. On a per-month basis, the average temperature increased in all months, with April showing a maximum rate of 0.41 °C per decade. (2) The amount of precipitation in the growing season increased in most regions, especially in western Xinjiang and Qinghai. The areas of reduced precipitation were mainly concentrated in the south of Gansu and Ningxia, the west of Shaanxi and the northeast of Xinjiang. The average precipitation also increased in all months, with June showing a maximum change rate of 1.8 mm per decade. (3) There were obvious spatial differences in the climate trends in northwest China with the warming shifting from areas of bare land to grassland and the trend towards increased rainfall shifting from grassland to bare land. These effects were most obvious in Xinjiang’s Tarim Basin. (4) From 1959 to 2019, the degree of drought in northwest China significantly decreased in most areas. The areas where drought decreased and precipitation increased were fairly consistent, which produced a strong spatial correlation between them.
Beyond-dipole van der Waals contributions within the many-body dispersion framework
Authors: Massa Dario , Ambrosetti Alberto , Silvestrelli Pier Luigi 
Published: November 2021

Abstract
By introducing a suitable range-separation of the Coulomb coupling in analogy to Ambrosetti et al (2014 J. Chem. Phys.
140 18A508), here we extend the many-body dispersion approach to include beyond-dipole van der Waals (vdW) interactions at a full many-body level, in combination with semi-local density functional theory. A reciprocal-space implementation is further introduced in order to efficiently treat periodic systems. Consistent reliability is found from molecular dimers to large supramolecular complexes and two-dimensional systems. The large weight of both many-body effects and multipolar terms illustrates how a correct description of vdW forces in large-scale systems requires full account of both contributions, beyond standard pairwise dipolar approaches.
A brief review on the recent evolution in piezoelectric linear ultrasonic motors
Authors: Mukhopadhyay Shalini , Behera Basudeba , Kumar Jayendra 
Published: November 2021

Abstract
This article represents the various recent advancements in the field of Piezoelectric Ultrasonic Motors, especially in linear type. The construction and operation principles evolving time to time. We have accumulated and presented a brief discussion on the linear ultrasonic motor including its working principles, initial designs, and recent advancements in this article. These motors have had increasing applications in recent years and have been developing rapidly due to their simplicity of construction and good performance. The potential applications are expanding lately to various areas such as medical devices, precise positioning systems, astronautical devices, tactile feedback systems, and many more. Owing to the wide range of applications, simple and compact design, rapidly increasing miniaturization, and the several advantages of the linear ultrasonic motor, it has been a vastly researched area in the last few decades. Continuous effort is being put into creating smaller and efficient designs, structures, and materials of the device, with stable and upgraded output performance, an acceptable range of frictional wear enabling prolonged usage.
Resolving Pseudohyponatremia: Validation of Plasma Sodium on Radiometer ABL800 Blood Gas Analyzers for Immediate Reflex Testing
Authors: Vera Michael A , Sutphin Angela , Hansen Lisa , El-Khoury Joe M 
Published: November 2021

Abstract

Objective
To perform validation of plasma sodium on blood gas analyzers to reflexively correct erroneous measurements by ion-selective electrodes (ISEs).

Methods
We compared remnant specimens of whole blood and plasma collected by lithium heparin vacutainer with normal protein concentrations and no lipemia. Whole-blood specimens were tested for sodium concentration on the ABL800 Flex blood gas analyzer, followed by centrifugation for plasma separation, and repeat sodium determination on an aliquot of the plasma only. Also, plasma specimens were analyzed by indirect ISE on the Cobas 8000 series and by direct ISE on the ABL800 Flex for instrument comparison.

Results
Plasma aliquots yielded comparable results to the parent whole-blood specimen, with an average change of −1.33 mmol/L (R2 = 0.9727). Comparison of indirect ISE to direct ISE similarly yielded comparable results, with an average change of + 0.8 mmol/L (R2 = 0.9016).

Conclusion
Plasma is a valid specimen matrix for use on blood gas analyzers for sodium determination, eliminating the need for re-collection of whole-blood specimens from patients with pseudohyponatremia.
Noise analysis in the European Pulsar Timing Array data release 2 and its implications on the gravitational-wave background search
Authors: Chalumeau A , Babak S , Petiteau A , Chen S , Samajdar A , Caballero R N , Theureau G , Guillemot L , Desvignes G , Parthasarathy A , Liu K , Shaifullah G , Hu H , van der Wateren E , Antoniadis J , Bak Nielsen A-S , Bassa C G , Berthereau A , Burgay M , Champion D J , Cognard I , Falxa M , Ferdman R D , Freire P C C , Gair J R , Graikou E , Guo Y J , Jang J , Janssen G H , Karuppusamy R , Keith M J , Kramer M , Lee K J , Liu X J , Lyne A G , Main R A , McKee J W , Mickaliger M B , Perera B B P , Perrodin D , Porayko N K , Possenti A , Sanidas S A , Sesana A , Speri L , Stappers B W , Tiburzi C , Vecchio A , Verbiest J P W , Wang J , Wang L , Xu H 
Published: November 2021

ABSTRACTThe European Pulsar Timing Array (EPTA) collaboration has recently released an extended data set for six pulsars (DR2) and reported evidence for a common red noise signal. Here we present a noise analysis for each of the six pulsars. We consider several types of noise: (i) radio frequency independent, ‘achromatic’, and time-correlated red noise; (ii) variations of dispersion measure and scattering; (iii) system and band noise; and (iv) deterministic signals (other than gravitational waves) that could be present in the PTA data. We perform Bayesian model selection to find the optimal combination of noise components for each pulsar. Using these custom models we revisit the presence of the common uncorrelated red noise signal previously reported in the EPTA DR2 and show that the data still supports it with a high statistical significance. Next, we confirm that there is no preference for or against the Hellings–Downs spatial correlations expected for the stochastic gravitational-wave background. The main conclusion of the EPTA DR2 paper remains unchanged despite a very significant change in the noise model of each pulsar. However, modelling the noise is essential for the robust detection of gravitational waves and its impact could be significant when analysing the next EPTA data release, which will include a larger number of pulsars and more precise measurements.
Collisional properties of cm-sized high-porosity ice and dust aggregates and their applications to early planet formation
Authors: Schräpler Rainer R , Landeck Wolf A , Blum Jürgen 
Published: November 2021

ABSTRACT
In dead zones of protoplanetary discs, it is assumed that micrometre-sized particles grow Brownian, sediment to the mid-plane and drift radially inward. When collisional compaction sets in, the aggregates collect slower and therefore dynamically smaller particles. This sedimentation and growth phase of highly porous ice and dust aggregates is simulated with laboratory experiments in which we obtained mm- to cm-sized ice aggregates with a porosity of 90 per cent as well as cm-sized dust agglomerates with a porosity of 85 per cent. We modelled the growth process during sedimentation in an analytical calculation to compute the agglomerate sizes when they reach the mid-plane of the disc. In the mid-plane, the dust particles form a thin dense layer and gain relative velocities by, e.g. the streaming instability or the onset of shear turbulence. To investigate these collisions, we performed additional laboratory drop tower experiments with the high-porosity aggregates formed in the sedimentary-growth experiments and determined their mechanical parameters, including their sticking threshold velocity, which is important for their further collisional evolution on their way to form planetesimals. Finally, we developed a method to calculate the packing-density-dependent fundamental properties of our dust and ice agglomerates, the Young’s modulus, the Poisson ratio, the shear viscosity, and the bulk viscosity from compression measurements. With these parameters, it was possible to derive the coefficient of restitution which fits our measurements. In order to physically describe these outcomes, we applied a collision model. With this model, predictions about general dust-aggregate collisions are possible.
Synthetic CO emission and the XCO factor of young molecular clouds: a convergence study
Authors: Borchert E M A , Walch S , Seifried D , Clarke S D , Franeck A , Nürnberger P C 
Published: November 2021

ABSTRACT
The properties of synthetic CO emission from 3D simulations of forming molecular clouds are studied within the SILCC-Zoom project. Since the time-scales of cloud evolution and molecule formation are comparable, the simulations include a live chemical network. Two sets of simulations with an increasing spatial resolution (dx = 3.9 pc to dx = 0.06 pc) are used to investigate the convergence of the synthetic CO emission, which is computed by post-processing the simulation data with the radmc-3d radiative transfer code. To determine the excitation conditions, it is necessary to include atomic hydrogen and helium alongside H2, which increases the resulting CO emission by ∼7–26 per cent. Combining the brightness temperature of 12CO and 13CO, we compare different methods to estimate the excitation temperature, the optical depth of the CO line and hence, the CO column density. An intensity-weighted average excitation temperature results in the most accurate estimate of the total CO mass. When the pixel-based excitation temperature is used to calculate the CO mass, it is over-/underestimated at low/high CO column densities where the assumption that 12CO is optically thick while 13CO is optically thin is not valid. Further, in order to obtain a converged total CO luminosity and hence 〈XCO〉 factor, the 3D simulation must have dx ≲ 0.1 pc. The 〈XCO〉 evolves over time and differs for the two clouds; yet pronounced differences with numerical resolution are found. Since high column density regions with a visual extinction larger than 3 mag are not resolved for dx ≳ 1 pc, in this case the H2 mass and CO luminosity both differ significantly from the higher resolution results and the local XCO is subject to strong noise. Our calculations suggest that synthetic CO emission maps are only converged for simulations with dx ≲ 0.1 pc.
On the nature of the single eclipse per 80d orbit of the H-rich luminous WN star WR22
Authors: Lenoir-Craig G , Antokhin I I , Antokhina E A , St-Louis N , Moffat A F J 
Published: November 2021

ABSTRACT
WR22 = HD 92740 is a bright (V = 6.4 mag), intrinsically luminous, double-line WN7h + O9III-V binary exhibiting one sharp 8 per cent deep eclipse near periastron in its elliptical (e = 0.6) 80-day orbit, when the WR-star passes in front of the O star, with no secondary eclipse. We apply two models (L96, A13) to probe the optical space-based light curves from BRITE-Constellation, including three separate, complete eclipses, that show increased (o-c) scatter compared to the rest of the observations outside the eclipses, likely due to O-star light encountering WR wind-clumps. L96 is a simple atmospheric-eclipse model, often applied to close WR + O binaries, where the O-star is considered a point-source. A13 considers a finite-disk O-star and allows for atmospheric, photospheric and reflection components to the eclipse, permitting a better characterization of its shape through a more physically realistic description of the structures for both stars in WR22. Nevertheless, A13 is still susceptible to uncertainties in the luminosity of the O-star before unique values for the orbital inclination and WR mass-loss rate can be estimated. We present solutions for the two extremes of the O-star, O9V and O9III. As photometry alone cannot allow us to discriminate between these, we compared our results to the spectral models found in the literature and determined the correct solution to be O9V. Our best-fitting A13 Model 1 gives i = 83.5 ± 0.4°, with $\dot{M}_{\rm WR} = (1.86 \pm 0.2) \times 10^{-5} \dot{M}_{\odot }/yr$. The flux ratio in the red BRITE band in this model is FO/FWR = 0.064 ± 0.002.
MeerKAT discovery of radio emission from the Vela X-1 bow shock
Authors: van den Eijnden J , Heywood I , Fender R , Mohamed S , Sivakoff G R , Saikia P , Russell T D , Motta S , Miller-Jones J C A , Woudt P A 
Published: November 2021

ABSTRACT
Vela X-1 is a runaway X-ray binary system hosting a massive donor star, whose strong stellar wind creates a bow shock as it interacts with the interstellar medium (ISM). This bow shock has previously been detected in H α and infrared, but, similar to all but one bow shock from a massive runaway star (BD+43o3654), has escaped detection in other wavebands. We report on the discovery of 1.3 GHz radio emission from the Vela X-1 bow shock with the MeerKAT telescope. The MeerKAT observations reveal how the radio emission closely traces the H α line emission, both in the bow shock and in the larger scale diffuse structures known from existing H α surveys. The Vela X-1 bow shock is the first stellar-wind-driven radio bow shock detected around an X-ray binary. In the absence of a radio spectral index measurement, we explore other avenues to constrain the radio emission mechanism. We find that thermal/free–free emission can account for the radio and H α properties, for a combination of electron temperature and density consistent with earlier estimates of ISM density and the shock enhancement. In this explanation, the presence of a local ISM overdensity is essential for the detection of radio emission. Alternatively, we consider a non-thermal/synchrotron scenario, evaluating the magnetic field and broad-band spectrum of the shock. However, we find that exceptionally high fractions (≳ 13 per cent) of the kinetic wind power would need to be injected into the relativistic electron population to explain the radio emission. Assuming lower fractions implies a hybrid scenario, dominated by free–free radio emission. Finally, we speculate about the detectability of radio bow shocks and whether it requires exceptional ISM or stellar wind properties.