bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of contrast-enhanced ultrasound imaging (CEUS) and super-resolution ultrasound (SRU) for the quantification of ischaemia flow redistribution: a theoretical study
Authors: Arthur Lachlan J M B , Voulgaridou Vasiliki , Butler Mairead B , Papageorgiou Georgios , Lu Weiping , McDougall Steven R , Sboros Vassilis
Published: November 2024

The study of microcirculation can reveal important information related to pathology. Focusing on alterations that are represented by an obstruction of blood flow in microcirculatory regions may provide an insight into vascular biomarkers. The current in silico study assesses the capability of contrast enhanced ultrasound (CEUS) and super-resolution ultrasound imaging (SRU) flow-quantification to study occlusive actions in a microvascular bed, particularly the ability to characterise known and model induced flow behaviours. The aim is to investigate theoretical limits with the use of CEUS and SRU in order to propose realistic biomarker targets relevant for clinical diagnosis. Results from CEUS flow parameters display limitations congruent with prior investigations. Conventional resolution limits lead to signals dominated by large vessels, making discrimination of microvasculature specific signals difficult. Additionally, some occlusions lead to weakened parametric correlation against flow rate in the remainder of the network. Loss of correlation is dependent on the degree to which flow is redistributed, with comparatively minor redistribution correlating in accordance with ground truth measurements for change in mean transit time,

dMTT

(CEUS, R = 0.85; GT, R = 0.82) and change in peak intensity,

d
I
p

(CEUS, R = 0.87; GT, R = 0.96). Major redistributions, however, result in a loss of correlation, demonstrating that the effectiveness of time-intensity curve parameters is influenced by the site of occlusion. Conversely, results from SRU processing provides accurate depiction of the anatomy and dynamics present in the vascular bed, that extends to individual microvessels. Correspondence between model vessel structure displayed in SRU maps with the ground truth was

>
91
%

for cases of minor and major flow redistributions. In conclusion, SRU appears to be a highly promising technology in the quantification of subtle flow phenomena due ischaemia induced vascular flow redistribution.
Comparison of automatic and physiologically-based feature selection methods for classifying physiological stress using heart rate and pulse rate variability indices
Authors: Iovino Marta , Lazic Ivan , Loncar-Turukalo Tatjana , Javorka Michal , Pernice Riccardo , Faes Luca
Published: November 2024

Objective. This study evaluates the effectiveness of four machine learning algorithms in classifying physiological stress using heart rate variability (HRV) and pulse rate variability (PRV) time series, comparing an automatic feature selection based on Akaike’s criterion to a physiologically-based feature selection approach. Approach. Linear discriminant analysis, support vector machines, K-nearest neighbors and random forest were applied on ten HRV and PRV indices from time, frequency and information domains, selected with the two feature selection approaches. Data were collected from 127 healthy individuals during different stress conditions (rest, postural and mental stress). Main results. Our results highlight that, while specific stress classification is feasible, distinguishing between postural and mental stress remains challenging. The used classifiers exhibited similar performance, with automatic Akaike Information Criterion-based feature selection proving overall better than the physiology-driven approach. Additionally, PRV-based features performed comparably to HRV-based ones, indicating their potential in outpatient monitoring using wearable devices. Significance. The obtained findings help to determine the most relevant HRV/PRV features for stress classification, potentially useful to highlight different physiological mechanisms involved during both challenges accompanied by a shift in the sympathovagal balance. The proposed approach may have implications for advancing stress assessment methodologies in clinical settings and real-world contexts for well-being evaluation.
Magnetic field sensor based on multiple Fano resonance in metal-insulator-metal waveguide coupled with cross-shape resonator
Authors: Li Zhuang , Chen Fang , Yang Wenxing
Published: November 2024

In this paper, an innovative plasmonic magnetic field sensor (MFS) that exploits a Metal-insulator-Metal (MIM) waveguide configuration with an asymmetric cross-shaped resonator is constructed. The design enables the observation of double Fano resonance in the transmission spectrum, resulting from the coupling between continuous spectrum and discrete spectrum. By incorporating magnetic fluid in the asymmetric cross-shape resonator, the Fano line shapes can be tuned by the external magnetic field. Finite-Difference Time-Domain (FDTD) is used to simulate the spectra response to external magnetic fields and geometrical sizes. The proposed structure exhibits remarkable magnetic field sensitivity of

12.1

p
m
/
O
e

within the detection range of

15

O
e

to

199

O
e
.

The resolution of MIM magnetic field sensors can reach

0.0826

O
e
.

The optimal figure of merit (FOM) and maximum Q factor of the Fano dip are about

6.9
×

10

−
4

/

O
e

and 66.74, respectively. Meanwhile, The proposed Fano resonance MFS has some advantages, including compact size, high sensitivity, and cost-effectiveness. A strong linear relationship between the magnetic field and resonance wavelength indicates that the proposed structure can find potential applications in diverse fields such as magnetic field sensors, aircraft navigation, and even nuclear energy generation.
Molecular dynamics-based study of the effects of grain size and temperature on the nanoscratching groove characteristics of grating polycrystalline layered Al films
Authors: Liu Jiye , Shi Guangfeng , Jiang Ziwei
Published: November 2024

Echelle gratings, a specialized type of diffraction grating, feature a periodic groove pattern that exhibits excellent light-splitting capabilities. These gratings are characterized by a low density of lines per millimeter and a significant blaze angle. The primary substrate for echelle gratings in mechanical scratching is an aluminum film with a layered structure, which is determined by the coating process. However, the unique interlayer structure of the layered aluminum film, combined with the challenges posed by deep and high-precision triangular diffraction grooves, complicates the control of the scratching process. This article aims to investigate the material removal process and the thermal field-assisted scratching mechanism in the nano-scratching of polycrystalline layered aluminum films, with a particular emphasis on the material removal mechanism involved in nano-scratching. It discusses the influence of the thermal field and grain size on the mechanical response and the material removal process, while thoroughly examining their effects on the accuracy of groove formation. The results indicate that as the temperature increases, both the frictional and normal forces exhibit a decreasing trend. Additionally, a reduction in grain size corresponds to smaller frictional and normal forces. This decrease in scratching force contributes to minimizing the deformation of the workpiece during the scratching process, which is advantageous for precise control of groove shape and enhances the scratching quality of large-area gratings. As the temperature increases, the number of atoms removed from the polycrystalline layered aluminum film rises, leading to an enhanced material removal rate. Consequently, the accuracy of the diffraction grating groove also improves. Concurrently, the presence of delaminated grain boundary interfaces impedes the downward propagation of defects such as dislocations and can accommodate these dislocations. As temperature rises, the total length of dislocation lines decreases. Elevated temperatures promote the transformation of the crystal structure into an amorphous state. The grain boundaries and interlayer grain boundaries at the delamination restrict the movement of dislocations. The deformation behavior suggests that grain boundaries significantly contribute to the suppression of strain and stress propagation, resulting in a gradient distribution at the layered grain boundary interface, which further impedes stress transmission. Stress and strain are concentrated not only in the contact area between the tool tip and the substrate but also within the grain boundaries and their adjacent regions.
Impact of nuclear level density and radiative strength function models on the S factors of (α, γ) reactions relevant to p-nuclei production
Authors: Nhu Le N
Published: November 2024

The astrophysical S factors of (α, γ) reactions are crucial inputs to nuclear reaction network simulations for studying p-nuclei production. Previous work revealed considerable discrepancies between theoretical and experimental S factors using different nuclear level densities (NLD) and radiative strength functions (RSF). Accordingly, in this article, we studied the influence of six RSF and four NLD models on the astrophysical S factors of (α, γ) reactions on 16 target nuclei. The microscopic NLD and RSF models under investigation are based on the Hartree–Fock + Bardeen-Cooper-Schrieffer (HFBCS) and Hartree–Fock-Bogulubov (HFB) mean-field calculations. The obtained results have shown that within the α-OMP proposed in Nhu Le and Quang Hung (2022 Phys. Rev. C 105 014602), RSF and NLD models used in the S factor computation yield root mean square (rms) deviations of less than 0.750, and phenomenological NLD and RSF models provide better predictions for astrophysical S factors than microscopic ones in all cases considered. More research is needed on NLD and RSF models to improve prediction accuracy and reduce deviations in calculations of the S factors of radiative α captures.
Advancing non-linear PDE's solutions: modified Yang transform method with Caputo-Fabrizio fractional operator
Authors: Ullah Abd , Ansari Khursheed J , Ullah Aman
Published: November 2024

Nonlinear partial differential equations have a crucial rule in many physical processes. In this paper, a novel approach is used to study nonlinear partial differential equations of fractional order, which is named as Modified Yang Transform (MYT) method. This approach combines Yang transform with the Adomian decomposition method. The fractional order is considered in the Caputo-Fabrizio sense. Convergence analysis of the modified Yang transform to nonlinear fractional order partial differential equations is presented. Additionally, a solution framework for the solution of nonlinear partial differential equation is carried out and some examples are provided to highlight the application of the current method. To illustrate that how the solution behaves for various fractional orders, 2D and 3D graphs are plotted. Various tables are also provided to show the difference between exact and approximate solutions and the values are compared with other methods in the literature. Results and discussion sections are included for each example to explain the graphs, tables and their results.
Unraveling coupling delays through a transfer entropy analysis in stochastic processes and non-linear systems
Authors: Salgado-García R , Rivera Islas A I , Gonzalez-Narvaez R E , Vázquez F , López de Haro M
Published: November 2024

In this work we propose a transfer entropy approach to discern time-delay couplings within non-linear and stochastic coupled systems. We introduce the concept of ‘time-wise transfer entropy’, which quantifies the reduction in future uncertainty for a process Y by considering the values of processes X and Y at a specific past moment. The key advantage of our approach is a reduction in the number of parameters required for estimation when compared to other transfer entropy methodologies. Our proposed time-wise transfer entropy not only lends itself to effective estimation from actual data but also enhances our understanding of the origins of seemingly ‘spurious’ couplings observed in some transfer entropy approaches. To validate our method, we apply it to determine coupling delays in minimal stochastic models where the time-wise transfer entropy can be precisely derived in terms of the Shannon entropy. We further assess the technique performance in coupled non-linear systems with delays, demonstrating its capacity to accurately reproduce the corresponding coupling delays. The developed technique may be useful in the analysis of multifactor non-linear physical systems where complex causal relationships may exist.
Thermoelastic field analysis using differential transform under Moore-Gibson-thompson theory
Authors: Sutar C S , Chaudhari Kamini K , Pimpare Sangita B , Pardeshi Yuvraj
Published: November 2024

Heat conduction has many applications in engineering fields. There are various heat conduction models have been studied in the last few years. The main objective of this research is to study the effect of MGT model on thermoelastic problem. Also, offer a strong tool-the DifferentialTransform Method- for solving the governing partial differential equations with a simpler computation load than existing approaches. This paper presents the mathematical model describing the MooreGibsonThompson (MGT) equation in rectangular plate. This MGT equation is modified into the heat conduction in the rectangular plate. Thermoelastic phenomena play a significant role in heat conduction, particularly in materials that experience both thermal and mechanical stresses. Thus the thermoelastic properties of rectangular plates were also studied using the two-dimensional mathematical model under MGT heat conduction. Goodier's function and Boussinesq harmonic functions techniques have been used to obtain the thermal stresses in rectangular plates. The results have been discussed using graphs drawn by the mathematical software MATLAB.
Splitting of triply quantized vortices in Bose–Einstein condensates of finite temperature
Authors: Yan Jun , Mo Jiexiong , Mo Lichang , Lan Shanquan , Xu Xiaobao , Li Guqiang , He Huandian
Published: November 2024

Utilizing the dissipative Gross–Pitaevskii equation, we investigated the splitting dynamics of triply quantized vortices at finite temperature. Through linear perturbation analysis, we determined the excitation modes of these vortices across various dissipation parameters. We identified three unstable modes with p = 2-, 3- and 4-fold rotational symmetries, revealing a significant dynamic transition of the most unstable mode. That is, as the dissipation parameter increases the most unstable mode transitions from the p = 2 mode to the p = 3 mode. Throughout the entire range of dissipation parameters, the p = 4 unstable mode is never the dominant mode. Subsequently, we performed nonlinear numerical simulations of the vortex splitting process. Under random perturbations we confirmed the dynamical transition, and under specific perturbations we confirmed the instability of the p = 4 mode. Our findings on the finite temperature dependence of the splitting dynamics of triply quantized vortices are expected to be verifiable in experiments.
Components and Anisotropy of 3D QFP Waves During the Early Solar Eruption
Authors: Hu Jialiang , Ye Jing , Chen Yuhao , Mei Zhixing , Xu Shanshan , Lin Jun
Published: November 2024

The propagation of disturbances in the solar atmosphere is inherently three-dimensional (3D), yet comprehensive studies on the spatial structure and dynamics of 3D wave fronts are scarce. Here we conduct high-resolution 3D numerical simulations to investigate filament eruptions, focusing particularly on the 3D structure and genesis of extreme ultraviolet (EUV) waves. Our results demonstrate that the EUV wave front forms a dome-like configuration subdivided into three distinct zones. The foremost zone, preceding the flux rope, consists of fast-mode shock waves that heat the adjacent plasma. Adjacent to either side of the flux rope, the second zone contains expansion waves that cool the nearby plasma. The third zone, at the juncture of the first two, exhibits minimal disturbances. This anisotropic structure of the wave front stems from the configuration and dynamics of the flux rope, which acts as a 3D piston during eruptions—compressing the plasma ahead to generate fast-mode shocks and evacuating the plasma behind to induce expansion waves. This dynamic results in the observed anisotropic wave front. Additionally, with synthetic EUV images from simulation data, the EUV waves are observable in Atmospheric Imaging Assembly 193 and 211 Å, which are identified as the fast-mode shocks. The detection of EUV waves varies with the observational perspective: the face-on view reveals EUV waves from the lower to the higher corona, whereas an edge-on view uncovers these waves only in the higher corona.
Parametric dependencies of ion temperature profile peaking in ASDEX Upgrade high-beta scenarios
Authors: Reisner M. , Di Siena A. , Fable E. , Stober J. , Fischer R. , McDermott R.M. , Bilato R. , Bock A. , Görler T. ,   the ASDEX Upgrade Team
Published: November 2024

Advanced Tokamak (AT) scenarios are attractive candidates for future nuclear fusion power plants. These scenarios often feature peaked temperature profiles, suggesting a local reduction of turbulent transport. The mechanisms behind this are, as yet, not fully understood. Parameters that are thought to be connected to these transport reductions include the q-profile and the E × B-shear

ω

E
×
B

. Another parameter considered to be important is the fast ion content, which can reduce transport in multiple different ways. This work presents AT experiments performed at the ASDEX Upgrade tokamak (AUG) in which these three parameters are varied to investigate their respective effect on the observed peaked ion temperature profiles. To disentangle potentially competing effects, simulations using the codes GENE and TGLF have been performed. It is found that the E × B-shear does not play a role in the AT scenarios performed at AUG, which have relatively low rotation, with

v

tor

=
100
−
250

km h−1. Experimentally, a significant dependence of

R

/

L

T

i

on the electron cyclotron current drive settings was found, indicating that either the current profile (and, therefore, the q-profile) or

T
e

/

T
i

has a significant impact on the observed suppression of turbulent transport. In support of the first option, both GENE and TGLF show a q-profile dependence of

R

/

L

T

i

. Furthermore, according to GENE, electromagnetic (EM) fast ion effects are essential in reproducing the experimental results. Scans with TGLF (which does not include such effects), suggest that these fast ion effects become relevant above a threshold of

R

/

L

T

i

=

4–5. In the presence of ICRF, additional electrostatic (ES) fast ion effects seem to come into effect, according to GENE, albeit to a smaller degree than the EM effects.
The role of ion-scale micro-turbulence in pedestal width of the DIII-D wide-pedestal QH mode
Authors: Li Zeyu , Chen Xi , Jian Xiang , Ernst Darin , Xu Xueqiao , Groebner R.J. , Wang Huiqian , Osborne T.H. , Burrell K.H. ,   the DIII-D Team
Published: November 2024

The low-edge rotation, intrinsically ELM-free, and improved confinement wide-pedestal quiescent H-mode (QH-mode), discovered in DIII-D tokamak, has pedestal widths exceeding the EPED-kinetic-ballooning mode (KBM) model scaling typically by at least 25%. Ion-scale (

k
y

ρ
s

< 1) microturbulence and its role in setting the pedestal structure is investigated using the radially local

δ
f

gyrokinetic code CGYRO. The electromagnetic trapped electron mode (TEM) is unstable at the pedestal top, while plasma beta (

β
e

)

is ∼60% below the KBM onset threshold and the electron temperature gradient mode is found to be unstable in the peak gradient region. Nonlinear simulation reveals that the ion-scale turbulence could produce electron energy flux consistent with the flux inferred from power balance at the pedestal top, with a reasonable variation of the local

E
×
B

shearing rate; and the local neoclassical transport from NEO is dominant over the simulated turbulent transport in the ion energy flux channel. The simulated ion-scale turbulence produces much lower electron energy flux than inferred from experiment in the pedestal peak gradient region. A correction to the EPED-KBM pedestal width scaling is obtained based on the two-dimensional scan of pedestal top plasma beta (

β
e

)

and normalized electron density and temperature scale lengths,

a

/

L

n
e

,

a

/

L

T
e

using CGYRO linear simulations. Mode transitions among TEM, micro-tearing mode, ion-temperature gradient mode and KBM, are observed in the 2D scan at the pedestal top. A fixed normalized growth rate for these drift-type modes is taken to determine the pedestal width scaling, which shows good consistency with the QH experimental database on pedestal heights and widths. The onset of KBM instabilities and the local E × B shear suppression criterion set the lower and upper limit for the pedestal width of standard QH-mode, wide-pedestal QH-mode and type-I ELMy H mode. A potentially higher and wider pedestal is expected from the new scaling of pedestal width. This work presents an improved understanding of the ion-scale micro-turbulence of wide-pedestal QH-mode and sheds light on a promising scenario for future reactors, including ITER and beyond.
Beam emission spectroscopy diagnostic design and capabilities for two-dimensional turbulence measurements on Wendelstein 7-X
Authors: Han X. , Smith D.R. , Windisch T. , Laube R. , Den Hartog D. , Seyfert C. , Gallenberger T. , Jaehnig K. , Geiger B. , McKee G. , Grulke O. ,   the Wendelstein 7-X team
Published: November 2024

A beam emission spectroscopy (BES) diagnostic is designed
for studying two-dimensional turbulent dynamics by measuring the
Doppler-shifted Balmer-Alpha emission (n = 3 → 2) from neutral
heating beams on Wendelstein 7-X (W7-X) stellarator. The BES viewing
geometry has been determined in the conceptual design
previously. However, the small Doppler shifts and small optical
throughput compared to a typical BES diagnostic demand dedicated
efforts on the optical assemblies and the detector module for the
BES system. We present the detailed opto-mechanical design and
specifications of BES, including a customized neutral beam viewing
optical system, a semi-telecentric optical assembly, and a detector
module for electronic amplification. The point spread function is
calculated using the pyFIDASIM code with experimental parameters and
W7-X magnetic configurations to estimate the BES spatial resolution
and beam intensity. The as-manufactured interference filter is
applied for the spectral isolated beam radiance calculation. Result
shows that the BES system is capable of measuring the ion-scale
turbulence for k
⊥
ρ

i
≤ 0.4 at r/a = 0.75 with reasonable
spatial and wavenumber resolutions. An integrated detector module is
fabricated where two 8×4 avalanche photodiode detectors (APD)
are embedded into the custom-designed pre-amplifier circuit to gain
signals to the desired level. The detector noise measurement is
performed and the signal-to-noise ratio (SNR) is evaluated. A
detectable fluctuation level can be achieved as low as
ñ

e
/n

e
≈ 0.5% at frequency f ≤ 400 kHz with a
bandwidth of 1 MHz.
Prevention of early thrombosis in transplanted vein model by encapsulation with tirofiban microneedle drug delivery system
Authors: Wang Bolin , Yang Yazhu , Ding Xiaohang , Sun Jiefang , Yu Wenyuan , Zhao Yuehua , Ma Qian , Yu Yang
Published: November 2024

Early thrombosis following coronary artery bypass grafting (CABG) surgery leads to perioperative myocardial infarction, which causes difficulties for clinicians and patients. Moreover, once perioperative myocardial infarction occurs, the mortality rate is extremely high. In recent years, microneedle (MN) drug delivery systems have become a research hotspot with broad clinical application prospects. These systems are capable of achieving sustained, safe, and painless local drug release. In cardiovascular applications, MNs maximize local anticoagulant effects, inhibit endometrial hyperplasia, and reduce systemic side effects. We speculate that a MN drug delivery system can be used to target transplanted veins to inhibit their thrombosis and reduce the incidence of perioperative myocardial infarction after CABG surgery. Therefore, this study developed a hyaluronic acid MN patch loaded with tirofiban and conducted preliminary physicochemical tests. The safety, efficacy, biocompatibility, and targeting of the MN system were evaluated using in vitro and in vivo experiments using a jugular vein transplantation model. The results indicate that the MN system has excellent physical properties, safety, effectiveness, biocompatibility, and strong targeting, which can effectively inhibit early local thrombus formation. In addition, the observation of early postoperative endometrial hyperplasia activation provides a foundation for future research.
Climate variability and worldwide migration: current evidence and future projections
Authors: Cattaneo Cristina , Massetti Emanuele , Farinosi Fabio , Dasgupta Shouro
Published: November 2024

The literature linking climatic drivers and migration is growing, but there is still limited evidence and substantial uncertainty regarding future bilateral flows driven by climate stress on a global scale. The aim of this paper is to fill this gap by projecting changes in the flows of international migrants from medium-term population and climate change projections. We employ a bilateral gravity equation for emigration rates controlling for decadal weather averages of temperature, precipitation, droughts, and extreme precipitation in the origin countries. We use the parameter estimates of the gravity equation to estimate global, regional, and country-by-country emigration flows for several combinations of socio-economic development and climate change. Results indicate that global emigration flows are projected to increase to around 110 million in 2060 for SSP1 and RCP 4.5 and SSP5 and RCP 4.5; to 135 million for SSP5 and RCP 8.5; to 163 million for SSP3 and RCP 4.5. We report that changes in emigration flows are largely due to population growth in the origin countries.
Cellulose extraction from Cladophora rupestris for extraction of nanomaterials
Authors: Persincula M R F , Madrazo C F
Published: November 2024

Cellulose from macroalgae is potential for the extraction of nanomaterials due to its availability and its great fraction in the biomass. Cladophora rupestris is a macroalgae and is a good material to which a cellulose may be extracted. The said macroalgae has no value-added products or uses yet. It has a lignocellulosic profile of: alpha-cellulose, 33.43 %; hemicellulose, 15.48%; holocellulose, 48.93; acid soluble lignin, 2.22%; acid insoluble lignin, 22.33%, extractives, 5.67% and total ash, 39.65%. Identifying the best method and conditions for the extraction of cellulose from the said material is a challenge that needs to be addressed. The process for the cellulose extraction considered variations on drying (oven, air, and sun drying), defatting (using solvents: methanol and hexane; and extraction time: 8 hrs and 4 days), solvent drying (oven and air drying), alkaline pre-treatment (0.1, 0.5, and 1M NaOH), fixed conditions on bleaching, bleached biomass oven drying. The biomass weight losses were monitored for some steps, attributing this on the removal of the lignin and extractives. The lignocellulosic profile of the crude cellulose extracted from the macroalgae using the best conditions was determined indicating an increased fraction of the cellulose components in the biomass and a transformation of the rigid biomass into a soft and paper-like texture. The functional groups present on the cellulose was determined. The extracted cellulose was used to produced cellulose nanofibril (CNF) with fiber diameter of the CNF ranges on 14.29 – 37.50 nm and crystallinity index of 92.48%. Attempts were done on extraction of cellulose nanocrystal (CNC) utilizing microwave-assisted acid hydrolysis (MAAH) and semi-batch acid hydrolysis (SBAH); and variation on the acid used (sulfuric acid, and oxalic acid), concentration of the acid, and the temperature conditions.
Fast biodiesel production via potassium ferrate catalysis at room temperature using used cooking oil and refined canola oil
Authors: Demafelis R B , Cases M K A , Sombilla J C , Migo V P , Matanguihan A E D , Landoy R J B
Published: November 2024

As biodiesel is continuously aimed to be a better alternative to petroleum-based diesel fuel, the University of the Philippines Los Baños – Interdisciplinary Biofuels Research Studies Center (UPLB-IBRSC) continues to explore process conversion techniques to improve efficiencies in biodiesel production. In this study, the catalytic activity of potassium ferrate in the transesterification of canola oil and used cooking oil for biodiesel production at room temperature was examined for potential reduction in energy consumption. Parameters such as methanol-to-oil molar ratio, catalyst loading, and reaction time were varied to determine their effects on biodiesel yield and purity. Thin layer chromatography was applied to qualitatively analyze the biodiesel, while ImageJ software was used for purity determination. The characterization analysis confirmed that the refined canola oil used in the study has an acceptable FFA content of 0.06%. On the other hand, the used cooking oil showed an FFA content of 3.71%, which is beyond the desired limit of 2%. Hence, neutralization through the addition of potassium hydroxide was performed, resulting in a lowered FFA content of 0.86%. Experimental results of the parametric and optimization study on used cooking oil showed that an optimum conversion of 86.55% was achieved at a 2:1 methanol-to-oil molar ratio, 5 wt% catalyst loading, and 90 minutes reaction time. Consequently, a yield of 83.21% was attained using refined canola oil at the optimum conditions of 6:1 methanol-to-oil molar ratio, 3 wt% catalyst loading, and 69 minutes reaction time. Generally, findings show that catalyst loading and reaction time significantly affect the biodiesel yield and purity only up to a certain optimum value. The methanol-to-oil ratio, on the other hand, showed to have a significant inverse relationship on yield and purity. Compared to the typical biodiesel production process at 60 °C with up to two hours of reaction time, this study which describes a catalytic process at room temperature and a relatively shorter reaction time, showed the potential to reduce significantly the high energy consumption in biodiesel production.
Cellulose acetate production using cacao pod husks from local sources for potential industrial applications
Authors: Magallanes-Nava Juniper V. , Tamargo Ramuel John I.
Published: November 2024

Cacao (Theobroma cacao) is one of the most important high-value crops worldwide. Cacao fruit is mainly composed the cacao beans, pulp, and husks. The cacao pod husk (CPH) accounts for almost 60-80% of the weight of the whole fruit. However, oftentimes, these CPH are discarded as waste. Amongst the potential use of CPH is the isolation of its cellulose. The lack of available studies exploring the cellulose content of CPH of different varieties of cacao in the Philippines, and the comparison of heating methods for its extraction, highlights a significant research gap. This knowledge will provide a more comprehensive understanding of its composition for potential applications. In this study, different sources and varieties of cacao pod husks were used to produce cellulose through alkali treatment and bleaching with conventional heating and microwave synthesis methods. The result showed that the microwave synthesis approach produces a comparable yield to the conventional method but at a lower treatment time. The cellulose produced was successfully converted into cellulose acetate as confirmed via FTIR analysis. The cellulose acetate was dissolved in different solvents as preparation for its use as one of the components for the development of bioplastic. Characterization of the film produced showed the potential of the cellulose acetate from cacao pod husk for bioplastic application.
Production of Bio-plasticized Polyvinyl Chloride (PVC) Films Synthesized from Microalgae (Chlorella vulgaris)
Authors: Ampong M L , Catapat D D , Panaligan D C , Pantaleon G M , Clemeña J R , Rubi R V , Lavilles F D , Gildo P J , Pangayao D
Published: November 2024

Bio-based plasticizers for PVC films are being explored to replace conventional phthalate-based plasticizers due to the threats they pose to human health and the environment. In the present study, fatty acids from Chlorella vulgaris were extracted via Microwave-assisted Extraction and were epoxidized using esterification and transesterification reactions in a magnetically stirred reactor to produce EFAME plasticizer. FTIR Analysis determined the presence of an epoxy group as the peak C=O stretch (1739.79 cm−1) was detected. PVC films were synthesized at different concentrations of EFAME (30%, 40%, and 60%). At 40% of EFAME, the PVC exhibited high displacement in the tensile strength and elongation at break test, which was used as a basis to produce PVC-A, PVC-B, and PVC-C, and was compared to phthalate-plasticized PVC film, PVC-D. SEM-EDX Analysis verified the presence of PVC and EFAME in the plasticized PVC films as Carbon, Oxygen, and Chlorine elements were detected. PVC A had the lowest weight loss percentage at 40.96% indicating it has developed high migration resistance among the extraction mediums used. DSC analysis confirmed the plasticizing effect of EFAME as the glass transition temperature of bioplasticized PVC films decreased. Using One-way ANOVA, the physicochemical tests of PVC films plasticized with EFAME showed significantly better results than PVC films plasticized by DOP. Thus, the present study indicates that the bio-based plasticizer derived from C. vulgaris is a better and a potential alternative for phthalates in plasticizing PVC films.
Effect of rubber surface pretreatment method on the rubberized precast concrete
Authors: Espiritu Danielle , Garcia Dale Tristan O. , Isidro Maridil Joy B. , Labadan Christine Jim I. , Sumagui Maria Francesca S. , Alano Vince Harvey O. , Roque Erison C.
Published: November 2024

Disposal of waste tires is one of the environmental problems that require urgent attention. Their durability and potential for leaching out toxic chemicals have been a problem associated with disposal. This led many researchers to conduct studies on its potential for reuse. Among them is its potential as alternative to natural aggregates in concrete. However, rubber normally negatively affects the mechanical properties of concrete due to its hydrophobic nature resulting to poor adhesion with cement. In this study, the researchers explored the effects of different pre-treatment methods of rubber from waste tires to improve its hydrophilicity, its workability when mixed Type I Portland cement, and the mechanical properties of the resulting “rubberized” concrete. The pretreatment methods considered included: 1) soaking rubber in polyvinyl alcohol at different concentrations (8%, 10% and 12%); 2) soaking rubber in a mixture of sodium hydroxide, potassium permanganate, and saturated sodium bisulfite solution; and 3) exposure to UVA/B/C radiation. The rubber pieces from waste tires were first shredded into 0.3-0.5mm pieces prior to pretreatment. Hydrophilicity was measured through the contact angle test using an Optical Theta Lite Tensiometer. Workability of the concrete mix was measured through slump test (ASTM C143). The results show that rubber soaked in PVA 10% yielded the lowest contact angle (better hydrophilicity) and the most similar workability with normal concrete. Several concrete specimens using the pretreated rubber aggregates were then produced and cured for 7 days and 28 days before subjecting to several tests to determine the compressive, tensile, and flexural strengths. Pretreatment by soaking in PVA yielded concrete with mechanical properties comparable and in some instances better than normal concrete.
Environmental Sustainability Assessment of Banana Peel Briquetting
Authors: Torres M V , Aberilla J M O
Published: November 2024

Continued population growth is expected to further strain the energy-food nexus, such as the increase of waste generation by 2050. Proper waste management is thus essential to manage the future scenarios. Banana is one of the highly produced crops globally, and especially in the Philippines, where one of its most notable wastes are the banana peels. It is estimated that 1.67 million metric tons of banana peel waste is generated from banana production in the Philippines. Despite the potential of BP across other applications, these technologies are not yet implemented on an industrial scale. While their potential as a raw material for various products has been researched extensively, the environmental sustainability of these technologies is yet to be measured. One of the technologies for utilizing waste biomass is briquetting. Briquettes are processed densified biomass which can be used as a substitute for conventional solid fuels, especially in household cooking. This study aims to report for the first time the environmental performance of industrial-scale banana peel briquetting from collected empirical data. Life cycle assessment is conducted through openLCA with ReCiPe 2016 Midpoint (H) being the impact assessment method. The results indicate that the production of briquetting performs better environmentally compared to the equivalent production of charcoal. The carbon footprint of producing briquettes from banana peels is 0.01 kg CO2-eq/MJ, over 95% lower than conventional charcoal. The briquettes from banana peels also indicate lower environmental impacts in categories such as agricultural land occupation, and fossil depletion potential. Contribution analysis of the system indicates that the use of binder contributes most to the impacts of briquetting production. Possible use of different binders or the development of different binders is expected to improve environmental performance. Alternative energy schemes for drying can also improve environmental performance.
Free-standing polyaniline-reduced graphene oxide (PANI-rGO) thermoelectric films via electrochemical synthesis
Authors: San Juan A M , Enriquez E P
Published: November 2024

Heat-based energy harvesting is gaining attention as an alternative energy source. Thermoelectric materials (TEs) generate voltages in response to a thermal gradient and conductive polymer-carbon composites have properties that make them favorable for these applications. Polyaniline-reduced graphene oxide (PANi-GO) thermoelectric thin films were fabricated by the electropolymerization of PANi with simultaneous co-deposition of graphene onto fluorine-doped tin oxide (FTO). Poly(butyl acrylate) was spin-coated onto these films as backing support to make a stable free-standing film of PANi-rGO. The free-standing film was formed upon GO reduction which resulted in simultaneous delamination from the FTO electrode. Compositional and morphological data were obtained via Raman microspectroscopy and scanning electron microscopy and the TE properties were measured in terms of the Seebeck coefficient and conductivities from Hall effect measurements. The Seebeck coefficients of the films measured between 6.6 μV K−1 to 13.4 μV K−1, whereas Hall effect conductivities ranged from 0.483 to 2.68 S cm−1. The highest film power factor measured was 0.025 μW m−1K−2. Varying the GO content used in the electropolymerized film did not have a significant effect on the overall TE property though varying the reduction cycle number and voltage resulted in significant changes in the film Seebeck coefficients and conductivities.
Structural and electrical properties of Ni-doped MnZn ferrite synthesized via solid state reaction
Authors: Mendoza JC , Arcangel M , Nucum JA , Cervera RB
Published: November 2024

MnZn ferrite is commonly studied due to its exceptional magnetic, electric, and catalytic properties, making it a promising material for hyperthermia applications, magnetic fluid, memory storage devices, drug delivery, virus detection, and photocatalysis. It was identified that divalent nickel cation substitution increases the ferrite conductivity and dielectric constant. This study targets to synthesize Ni-doped MnZn ferrite by a simpler, more convenient, and economic solid state reaction, and to investigate its influence on the structural and electrical properties of MnZn ferrite. Mn0.5-xNixZn0.5Fe2O4 (x=0.1 and 0.2) was synthesized via solid state reaction with calcination and sintering temperature at 1000 °C and 1200 °C, respectively. The structural and electrical properties of the resulting pellet were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The XRD profile, indexed as cubic spinel, indicated good crystallinity and no impurity peaks were detected. As Ni2+ dopant concentration increases, a decrease in lattice parameter and an increase in theoretical and apparent densities were observed. This is attributed to the smaller ionic radius and greater mass of Ni2+ relative to Mn2+. Varying Ni2+ concentration significantly modified the morphology of the ferrite. At higher Ni2+, less uniformity in shape and size was evident in the SEM micrograph since Ni promotes aggregation at the surface. An increase in dielectric constant was also observed with increasing Ni2+ molar concentration. Since Ni2+ presents a high tendency to occupy B sites, its substitution promotes Fe2+ migration to A sites, augmenting Fe2+/Fe3+ hopping resulting in an increase in polarization and dielectric constant.
Comparison of single-vs dual-chamber microbial electrolysis cells performance for biohydrogen production
Authors: Isla-Cabaraban M T , Paclijan S , Logico N P , Dalagan J M , Gonzales F A , Cabaraban G M S , Tan N P
Published: November 2024

In this study, fed batch single- and dual-chamber microbial electrolysis cells (MECs) were operated to compare differences in the electrohydrogenesis performance at 0.8 V applied voltage and hydraulic retention time (HRT) of 48 h. Results showed that current intensity, current density, COD removal efficiency, and H2 production rate were higher in the dual-chamber MEC than in the single-chamber configuration. Electromethanogenesis and homoacetogenesis scavenged the H2 from electrohydrogenesis thus reducing H2 generation, as demonstrated by cathodic efficiencies less than 10%. It appears that homoacetogenesis overshadowed H2 production in the dual-chamber MEC, as reflected by a coulombic efficiency greater than 100%, likely induced by a high H2 partial pressure. These results portray MECs as an energy-efficient scheme for bioH2 production in addition to removal of pollutants (COD). This study presented valuable information when deciding on suitable reactors and optimizing reactor design.
Generation mechanism and anti-friction effect evaluation of continuous micro-groove texture machined by ball-end milling process
Authors: Huang Weimin , Huang Yuchao , Li Anbang , Zhou Xiangyuan , Wan Cong , Wang Guijie
Published: November 2024

Based on ball-end milling cutter characteristics, it takes advantage of the flexibility and controllability of its tool path during processing. The aim of this research is to process continuous microgroove textured surfaces by using ball-end milling cutters. Evaluation of the anti-friction effect of continuous microgroove texture by combining simulation and friction tests. The results indicate that, the surface topography of continuous microgrooves can be obtained by combining small feed per tooth and large radial cutting depth. The radial depth of cut and tool radius affect aspect ratio of microgrooves. The bearing capacity of the oil film shows an increasing and then decreasing trend with the increase of radial depth of cut and orientation angle. The radial depth of cut increased from 0.1 mm to 0.3 mm, resulting in a maximum 4.87% increase in the bearing capacity of oil film because of the enhanced wedge effect. However, further increase in radial depth of cut leads to increased vortex, weakening the wedge effect. The oil film bearing capacity is reduced so that the friction coefficient increases by a maximum of 510%. Moreover, as the orientation angle increases from 10° to 20°, the bearing capacity of the oil film increases by 22.7%. The minimum friction coefficient currently is 0.0215. However, when the microgroove orientation angle is further increased, the countercurrent effect is enhanced and the dynamic pressure effect is weakened, which finally leads to a decrease in the bearing capacity of the oil film. The friction coefficient has increased by 30.2% maximum. This study is of great significance which provides a new method for guiding the friction reduction on the die surface.
Development of age-specific population-based paediatric computational phantoms for image-based data mining and other radiotherapy applications
Authors: Ahmad Reem , Cantwell Jessica , Borrelli Carolina , Lim Pei , D’Souza Derek , Gaze Mark N , Moinuddin Syed , Gains Jennifer , Veiga Catarina
Published: November 2024

Objective. Computational anatomical models have many applications in paediatric radiotherapy. Age-specific computational anatomical models were historically developed to represent average and/or healthy individuals, where cancer patients may present with anatomical variations caused by the disease and/or treatment effects. We developed RT-PAL, a library of computational age-specific voxelized anatomical models tailored to represent the paediatric radiotherapy population. Approach. Data from patients undergoing craniospinal irradiation (CSI) were used (n = 74, median age 7.3y, range: 1–17y). The RT-PAL phantoms were generated using groupwise deformable image registration to spatially normalize and average a sub-set of twenty clinical CTs and contours (n = 74, median age 7.7y, range: 3–14 y). To assess their anatomical and age-dependency plausibility, the RT-PAL models were compared against clinical cancer patient data and two healthy population based libraries of phantoms: the International Commission on Radiological Protection (ICRP) pediatric reference computational phantoms (n = 8, median age 7.5y, range: 1–15y) and a range of 4D paediatric extended cardiac torso (XCAT) phantoms (n = 75, median age 9.1y, range: 1–18y). For each dataset, nineteen organs were segmented on all age models to determine their volume. Each set was evaluated through a linear fit of organ volume with age, where comparisons were made relative to the linear fit of the clinical data. Main Results. Overall good anatomical plausibility was found for the RT-PAL phantoms. The age-dependency reported was comparable to both the clinical data and other phantoms, demonstrating their efficacy as a library of age-specific phantoms. Larger discrepancies with the clinical, ICRP and XCAT organ data were attributable to differences in organ filling, segmentation strategy and age distribution of the datasets, limitations of RT-PAL generation methodology, and/or possible anatomical differences between healthy and cancer populations. Significance. The RT-PAL models showed potential in representing the paediatric radiotherapy cohort, who are most likely to benefit from dedicated, age-specific anatomical phantoms.