bluuebunny/crossref_metadata_2025 huggingface dataset:
Si–rhodamine derivative with a large stokes shift for ELISA-based detection of SARS-CoV-2
Authors: Liu Yan-Hong , Zhang Hong , Yu Kang-Kang , Pei Xiao-Fang , Xu Jia-Nan , Chen Shan-Yong , Yu Xiao-Qi , Li Kun
Published: April 2024

An Si–rhodamine derivative with a large Stokes shift and high fluorescence brightness was applied to distinguish normal serum from serum of COVID-19 patients.
Organic semiconductor nanoparticles for visible-light-driven CO2 conversion
Authors: Ferree Mariia , Kosco Jan , Alshehri Nisreen , Zhao Lingyun , De Castro Catherine S. P. , Petoukhoff Christopher E. , McCulloch Iain , Heeney Martin , Laquai Frédéric
Published: April 2024

We present an experimental proof-of-concept study of organic semiconductor nanoparticles (NPs) for visible-light-driven carbon dioxide (CO2) conversion.
Operando X-ray absorption spectroscopy of Fe–N–C catalysts based on carbon black and biomass-derived support materials for the ORR
Authors: Wartner Garlef , Müller-Hülstede Julia , Trzesniowski Hanna , Wark Michael , Wagner Peter , Seidel Robert
Published: April 2024

Novel biomass based Fe–N–C catalysts exhibit a higher density of FeNx type sites with different redox characteristics compared to carbon black based Fe–N–Cs. These different characteristics are influenced by heteroatom doping and undercoordination.
Resource limitation and population fluctuation drive spatiotemporal order in microbial communities
Authors: Khandoori Rohit , Mondal Kaustav , Ghosh Pushpita
Published: April 2024

Resource-driven dynamics in bacterial colonies. Insights into cell length regulation and spatial organization reveal the complex interplay between resources and microbial community dynamics.
Development of diverse aluminium concentration gradient profiles in Ni-rich layered cathodes for enhanced electrochemical and thermal performances
Authors: Jiao Xinwei , Yap Junwei , Choi Junbin , Chen Mengyuan , Darbar Devendrasinh , Qi Gongshin , Huang Xiaosong , Kim Jung-Hyun
Published: April 2024

Nickel (Ni)-rich cathodes with elemental concentration gradients within particles have attracted great interest due to their considerably enhanced interfacial stability and electrochemical performance for advanced Li-ion batteries.
Biodegradable calcium carbonate carriers for the topical delivery of clobetasol propionate
Authors: Saveleva Mariia S. , Verkhovskii Roman A. , Demina Polina A. , Surkov Yury I. , Anisimov Roman A. , Prikhozhdenko Ekaterina S. , Pidenko Pavel S. , Serebryakova Isabella A. , Zaytsev Sergey M. , Tuchin Valery V. , Svenskaya Yulia I.
Published: April 2024

Vaterite carriers were used to design a novel topical formulation for clobetasol propionate, which was capable of intrafollicular accumulation. Gradual degradation of the carriers in skin in vivo paves the way for improved safety and release profile.
Optimization of thermoelectric parameters for quantum dot-assisted polymer nanocomposite
Authors: Shisodia Shivani , Sahraoui Abdelhak Hadj , Duponchel Benoit , Singh Dharmendra Pratap , Depriester Michael
Published: April 2024

Heterogeneous nanostructures serve dual purposes as energy filters and phonon scatterers to effectively optimize thermoelectric performance.
Can Videoconferencing Be a Viable Method to Measure Speech Perception?
Authors: Shukla Bhanu , Moncrieff Deborah
Published: April 2024

Purpose:

Telehealth has proven effective for service delivery to remote and rural locations and was helpful during lockdowns when patients were unable to see clinicians in person. To assure the reliability of clinical services, the aim of the present study was to evaluate a telehealth protocol to measure speech perception skills through virtual meeting applications such as Zoom.

Method:

A total of 20 participants with normal hearing and cognition participated in the study. Participants' speech perception performance was measured in two sessions: one over a Zoom call and one in person in the laboratory. Speech perception was measured using Quick Speech-in-Noise Test, Bamford–Kowal–Bench Speech-in-Noise Test, and Words-in-Noise Test.

Results:

Statistical analysis revealed no significant differences between speech perception scores obtained over the Zoom and in-person methodologies for any of the tests. Additionally, our study found no significant difference in the scores obtained between wired and wireless headphones during Zoom calls.

Conclusion:

These results suggest that Zoom can be used as a reliable method to measure speech perception in young individuals with normal hearing using these three tests in situations where conventional methods cannot be utilized.
The Predictability of Naturalistic Evaluation of All-Day Recordings for Speech and Language Development
Authors: Ha Seunghee
Published: April 2024

Objectives:

The study aimed to investigate the predictive potential of language environment and vocal development status measures obtained through integrated analysis of Language ENvironment Analysis (LENA) recordings during the prelinguistic stage for subsequent speech and language development in Korean-acquiring children. Specifically, this study explored whether measures from both LENA-automated analysis and human coding at 6–8 months and 12–14 months of age predict vocabulary and phonological development at 18–20 months.

Method:

One-day home recordings from 20 children were collected using a LENA recorder at 6–8 months, 12–14 months, and 18–20 months. Both LENA-automated measures and measures from human coding were obtained from recordings at 6–8 months and 12–14 months. The number of different words, consonant inventory, and utterance structure inventory were identified from recordings of 18–20 months. Correlation and multiple regression analyses were performed to investigate whether measures related to early language environment and child vocalization at 6–8 months and 12–14 months were predictive of vocabulary and phonological measures at 18–20 months.

Results:

The results showed that the two main LENA-automated measures, conversational turn count (CTC) and child vocalization count, were positively correlated with all vocabulary and phonological measures at 18–20 months. Multiple regression analysis revealed that CTC during the prelinguistic stages was the most significant predictor of a number of different words, consonant inventory, and utterance structure inventory at 18–20 months. Also, adult word count in LENA-automated measures, child-directed speech ratio, and canonical babbling ratio measured by human coding significantly predicted some vocabulary and phonological measures at 18–20 months.

Conclusion:

This study highlights the multifaceted nature of language acquisition and collectively emphasizes the value of considering both quantitative and qualitative aspects of language input to understand early language development in children.
Trustworthy semi‐supervised anomaly detection for online‐to‐offline logistics business in merchant identification
Authors: Li Yong , Wang Shuhang , Xu Shijie , Yin Jiao
Published: April 2024

The rise of online‐to‐offline (O2O) e‐commerce business has brought tremendous opportunities to the logistics industry. In the online‐to‐offline logistics business, it is essential to detect anomaly merchants with fraudulent shipping behaviours, such as sending other merchants' packages for profit with their low discounts. This can help reduce the financial losses of platforms and ensure a healthy environment. Existing anomaly detection studies have mainly focused on online fraud behaviour detection, such as fraudulent purchase and comment behaviours in e‐commerce. However, these methods are not suitable for anomaly merchant detection in logistics due to the more complex online and offline operation of package‐sending behaviours and the interpretable requirements of offline deployment in logistics. MultiDet, a semi‐supervised multi‐view fusion‐based Anomaly Detection framework in online‐to‐offline logistics is proposed, which consists of a basic version SemiDet and an attention‐enhanced multi‐view fusion model. In SemiDet, pair‐wise data augmentation is first conducted to promote model robustness and address the challenge of limited labelled anomaly instances. Then, SemiDet calculates the anomaly scoring of each merchant with an auto‐encoder framework. Considering the multi‐relationships among logistics merchants, a multi‐view attention fusion‐based anomaly detection network is further designed to capture merchants' mutual influences and improve the anomaly merchant detection performance. A post‐hoc perturbation‐based interpretation model is designed to output the importance of different views and ensure the trustworthiness of end‐to‐end anomaly detection. The framework based on an eight‐month real‐world dataset collected from one of the largest logistics platforms in China is evaluated, involving 6128 merchants and 16 million historical order consignor records in Beijing. Experimental results show that the proposed model outperforms other baselines in both AUC‐ROC and AUC‐PR metrics.
Fast quadratic model predictive control based on sensitivity analysis and Wolfe method
Authors: Kalantari Hamid , Mojiri Mohsen , Askari Javad , Zamani Najmeh
Published: April 2024

This paper proposes a new algorithm based on sensitivity analysis and the Wolfe method to solve a sequence of parametric quadratic programming (QP) problems such as those that arise in quadratic model predictive control (QMPC). The Wolfe method, based on Karush–Kuhn–Tucker conditions, has been used to convert parametric QP problems to parametric linear programming (LP) problems, and then the sensitivity analysis is applied to solve the sequence of the parametric LP problems. This strategy obtains sensitivity analysis‐based QMPC (SA‐QMPC) algorithm. It is proved that the computational complexity of SA‐QMPC is for a region of the initial conditions and for sufficiently small sampling time and all initial conditions, where and are the horizon time and dimension of the state vector, respectively. Numerical results indicate the potential and properties of the proposed algorithm.
RCP‐RF: A comprehensive road‐car‐pedestrian risk management framework based on driving risk potential field
Authors: Tan Shuhang , Wang Zhiling , Zhong Yan
Published: April 2024

Recent years have witnessed the proliferation of traffic accidents, which led wide researches on automated vehicle (AV) technologies to reduce vehicle accidents, especially on risk assessment framework of AV technologies. However, existing time‐based frameworks cannot handle complex traffic scenarios and ignore the motion tendency influence of each moving objects on the risk distribution, leading to performance degradation. To address this problem, a comprehensive driving risk management framework named RCP‐RF is novelly proposed based on potential field theory under connected and automated vehicles environment, where the pedestrian risk metric is combined into a unified road‐vehicle driving risk management framework. Different from existing algorithms, the motion tendency between ego and obstacle cars and the pedestrian factor are legitimately considered in the proposed framework, which can improve the performance of the driving risk model. Moreover, it requires only of time complexity in the proposed method. Empirical studies validate the superiority of our proposed framework against state‐of‐the‐art methods on real‐world dataset NGSIM and real AV platform.
End‐to‐end demonstration for CubeSatellite quantum key distribution
Authors: Zhang Peide , Sagar Jaya , Hastings Elliott , Stefko Milan , Joshi Siddarth , Rarity John
Published: April 2024

Quantum key distribution (QKD) provides a method of ensuring security using the laws of physics, avoiding the risks inherent in cryptosystems protected by computational complexity. Here, the authors investigate the feasibility of satellite‐based quantum key exchange using low‐cost compact nano‐satellites. The first prototype of system level quantum key distribution aimed at the Cube satellite scenario is demonstrated. It consists of a transmitter payload, a ground receiver and simulated free space channel to verify the timing and synchronisation (T&S) scheme designed for QKD and the required high loss tolerance of both QKD and T&S channels. The transmitter is designed to be deployed on various up‐coming nano‐satellite missions in the UK and internationally. The effects of channel loss, background noise, gate width and mean photon number on the secure key rate (SKR) and quantum bit error rate (QBER) are discussed. The authors also analyse the source of QBER and establish the relationship between effective signal noise ratio (ESNR) and noise level, signal strength, gating window and other parameters as a reference for SKR optimisation. The experiment shows that it can tolerate the 40 dB loss expected in space to ground QKD and with small adjustment decoy states can be achieved. The discussion offers valuable insight not only for the design and optimisation of miniature low‐cost satellite‐based QKD systems but also any other short or long range free space QKD on the ground or in the air.
Lumped‐element equivalent circuit modelling of district heating pipe in electromagnetic transients program
Authors: Jiang Mingyu , Xia Yue , Lan Tian , Song Ruikai , Du Songhuai , Su Juan
Published: April 2024

Electromagnetic transients program (EMTP) is widely used to analyze transients in power systems. With the increased interest in integrated energy systems (IESs), it would be beneficial to extend the application of EMTP to multi‐physics transients in integrated electrical and heating networks. In this paper, an accurate and efficient lumped‐element circuit model of the heating district pipe is developed in EMTP. The pipe is split into segments using spatial discretization. The application of the numerical discretization to the energy conservation equation gives the discretized pipe equation which is expressed in the form of a companion model of EMTP. In order to reduce the computational effort, the time‐varying terms in the admittance matrix of the companion model of pipe are eliminated. The modification of the admittance matrix is avoided. Furthermore, the internal nodes resulting from spatial discretization are eliminated, resulting in a lumped‐element circuit model with only two external nodes. Case studies are carried out to validate the proposed model in terms of accuracy and efficiency. The 2‐norm error of the proposed model is 0.0153%. With a pipe length of 100 m, the computational speed of the proposed model is increased by a factor of 2.94 compared with the existing distributed‐element circuit model. The implementation of the proposed pipe model in the EMTP‐type simulator enables the analysis of multi‐physics transients in a multi‐carrier energy system.
THE THREE HUNDRED: Contrasting cluster galaxy density in hydrodynamical and dark matter simulations
Authors: Jiménez Muñoz A. , Macías-Pérez J. F. , Yepes G. , De Petris M. , Ferragamo A. , Cui W. , Gómez J. S.
Published: April 2024

Cluster number counts at visible and IR wavelengths will be a key cosmological probe in the next decade thanks to the Euclid satellite mission. For this purpose, the performance of cluster detection algorithms, which at these wavelengths are sensitive to the spatial distributions of the cluster galaxy members and their luminosity functions, need to be accurately characterized. Using THE THREE HUNDRED hydrodynamical and dark-matter-only simulations, we studied a complete sample of massive clusters beyond 7 (5) × 1014 M⊙ at redshift 0 (1) on a (1.48 Gpc)3 volume. We find that the mass resolution of the current hydrodynamical simulations (1.5 × 109 M⊙) is not enough to characterize the luminosity function of the sample in the perspective of Euclid data. Nevertheless, these simulations are still useful to characterize the spatial distribution of the cluster substructures assuming a common relative mass threshold for the different flavours and resolutions. By comparing with the dark-matter-only version of these simulations, we demonstrate that baryonic physics preserves significantly low-mass subhalos (galaxies), as has also been observed in previous studies with less statistics. Furthermore, by comparing the hydro simulations with higher resolution dark-matter-only simulations of the same objects and taking the same limit in subhalo mass, we find galaxy density profiles that are significantly more cuspy towards the centre of the clusters, where the low-mass substructures tend to concentrate. We conclude that using a dark-matter-only simulation may lead to some biases on the spatial distribution and density of galaxy cluster members. Based on the preliminary analysis of few high-resolution hydro simulations we conclude that a mass resolution of 1.8 × 108h−1 M⊙ will be needed for THE THREE HUNDRED simulations to approach the expected magnitude limits for the Euclid survey. These simulations are currently under way.
Probing the shape of the brown dwarf desert around main-sequence A-F-G-type stars using post-common-envelope WD−BD binaries
Authors: Chen Zhangliang , Chen Yizhi , Chen Chen , Ge Hongwei , Ma Bo
Published: April 2024

Context. Brown dwarfs (BDs) with masses in the range 40−60 MJup are rare around solar-type main-sequence (MS) stars, which gives rise to the brown dwarf desert (BDD). One caveat associated with previous studies of BDD is the relatively limited sample size of MS−BD binaries with accurately determined BD masses.

Aims. We aim to produce a large sample of BD companions with precisely determined masses around MS A-F-G-type stars using observations of post-common-envelope white dwarf (WD)−BD binaries.

Methods. We employed the rapid binary evolution code COMPAS to deduce the properties of MS−BD binary progenitors from post-common-envelope WD−BD binaries. With this method, we increase the sample of directly observed MS−BD binaries, enriching the data available for analyzing the BDD around MS A-F-G-type stars.

Results. Our study opens a new window for studying the shape of the BDD around A-F-G-type MS stars in the short-period regime. We find tentative evidence, albeit with a small sample size, that the “driest” part of the BDD around A-F-G-type stars may extend into an orbital period of several hundred days. More post-common-envelope WD−BD binaries detected in the future will advance our understanding of the BDD around A-F-G-type stars.
Impact of far-side structures observed by Solar Orbiter on coronal and heliospheric wind simulations
Authors: Perri B. , Finley A. , Réville V. , Parenti S. , Brun A. S. , Strugarek A. , Buchlin É.
Published: April 2024

Context.Solar Orbiter is a new space observatory that provides unique capabilities to understand the heliosphere. In particular, it has made several observations of the far-side of the Sun and therefore provides unique information that can greatly improve space weather monitoring.

Aims.In this study, we aim to quantify how the far-side data will affect simulations of the corona and the interplanetary medium, especially in the context of space weather forecasting.

Methods.To do so, we focused on a time period with a single sunspot emerging on the far-side in February 2021. We used two different input magnetic maps for our models: one that includes the far-side active region and one that does not. We used three different coronal models typical of space weather modeling: a semi-empirical model (potential field source surface or PFSS) and two different magnetohydrodynamic models (Wind Predict and Wind Predict-AW). We compared all the models with both remote sensing and in situ observations in order to quantify the impact of the far-side active region on each solution.

Results.We find that the inclusion of the far-side active region in the various models has a small local impact due to the limited amount of flux of the sunspot (at most 8% of the total map flux), which leads, for example, to coronal hole changes of around 7% for all models. Interestingly, there is a more global impact on the magnetic structure seen in the current sheet, with clear changes, for example, in the coronal hole boundaries visible in extreme ultra-violet (EUV) on the western limb, which is opposite to the active region and the limb most likely to be connected to Earth. For the Wind Predict-AW model, we demonstrate that the inclusion of the far-side data improves both the structure of the streamers and the connectivity to the spacecraft.

Conclusions.In conclusion, the inclusion of a single far-side active region may have a small local effect with respect to the total magnetic flux, but it has global effects on the magnetic structure, and thus it must be taken into account to accurately describe the Sun-Earth connection. The flattening of the heliospheric current sheet for all models reveals that it causes an increase of the source surface height, which in return affects the open and closed magnetic field line distributions.
Impact of disc magnetisation on MHD disc wind signature
Authors: Datta Sudeb Ranjan , Chakravorty Susmita , Ferreira Jonathan , Petrucci Pierre-Olivier , Kallman Timothy R. , Jacquemin-Ide Jonatan , Zimniak Nathan , Wilms Joern , Bianchi Stefano , Parra Maxime , Clavel Maïca
Published: April 2024

Context. Observations of blue-shifted X-ray absorption lines indicate the presence of wind from the accretion disc in X-ray binaries. Magnetohydrodynamic (MHD) driving is one possible wind-launching mechanism. Recent theoretical developments have made self-similar magnetic accretion-ejection solutions much more generalised, showing that wind can be launched at a much lower magnetisation than the equipartition value, which had previously been the only possibility.

Aims. In this work, we model the transmitted spectra through MHD-driven photoionised wind models with different levels of magnetisation. We investigate the possibility of detecting absorption lines by upcoming instruments, such as XRISM and Athena. We investigate the robustness of the method of fitting asymmetric line profiles by multiple Gaussians.

Methods. We used the photoionisation code XSTAR to simulate the transmitted model spectra. To cover the extensive range of velocity and density of the wind spanned over a large distance (∼105 gravitational radii), we divided the wind into slabs following a logarithmic radial grid. Fake observed spectra are finally produced by convolving model spectra with instrument responses. Since the line asymmetries are apparent in the convolved spectra as well, this can be used in future XRISM and Athena spectra as an observable diagnostic to fit for. We applied some amount of rigor in assessing the equivalent widths of the major absorption lines, including the Fe XXVI Lyα doublets, which will be clearly distinguishable thanks to the superior quality of future high-resolution spectra.

Results. Disc magnetisation stands as another crucial MHD variable that can significantly alter the absorption line profiles. Pure MHD outflow models at low magnetisation are dense enough to be observed by the existing or upcoming instruments. Therefore, these models can serve as simpler alternatives to MHD-thermal models. Fitting with multiple Gaussians is a promising method for handling asymmetric line profiles, as well as the Fe XXVI Lyα doublets.
MUSE view of PDS 456: Kiloparsec-scale wind, extended ionized gas, and close environment
Authors: Travascio A. , Piconcelli E. , Bischetti M. , Cresci G. , Feruglio C. , Perna M. , Vietri G. , Carniani S. , Cantalupo S. , Cicone C. , Ginolfi M. , Venturi G. , Zubovas K. , Bongiorno A. , Brusa M. , Luminari A. , Mainieri V. , Marconi A. , Menci N. , Nardini E. , Pensabene A. , Ramos Almeida C. , Tombesi F. , Vignali C. , Zappacosta L. , Fiore F.
Published: April 2024

PDS 456 is the most luminous (Lbol ∼ 1047erg s−1) radio-quiet quasar atz < 0.3 and can be regarded as a local counterpart of the powerful quasars shining at Cosmic Noon. It hosts a strong nuclear X-ray ultra-fast (∼0.3c) outflow, and a massive and clumpy CO (3–2) molecular outflow extending up to ∼5 kpc from the nucleus. We analyzed the first MUSE Wide Field Mode (WFM) and Adaptive-Optics Narrow Field Mode (AO-NFM) optical integral field spectroscopic observations of PDS456. The AO-NFM observations provide an unprecedented spatial resolution, reaching up to ∼280 pc. Our findings reveal a complex circumgalactic medium around PDS 456, extending to a maximum projected size of ≈46 kpc. This includes a reservoir of gas with a mass of ∼107 − 108M⊙, along with eight companion galaxies and a multi-phase outflow. WFM and NFM MUSE data reveal an outflow on a large scale (≈12 kpc from the quasar) in [O III], and on smaller scales (within 3 kpc) with higher resolution (about 280 pc) in Hα, respectively. The [O III] outflow mass rate is 2.3 ± 0.2M⊙yr−1which is significantly lower than those typically found in other luminous quasars. Remarkably, the Hαoutflow shows a similar scale, morphology, and kinematics to the CO (3–2) molecular outflow, with the latter dominating in terms of kinetic energy and mass outflow rate by two and one orders of magnitude, respectively. Our results therefore indicate that mergers, powerful active galactic nucleus (AGN) activity, and feedback through AGN-driven winds collectively contribute to shaping the host galaxy evolution of PDS 456, and likely that of similar objects at the brightest end of the AGN luminosity function across all redshifts. Moreover, the finding that the momentum boost of the total outflow deviates from the expected energy-conserving expansion for large-scale outflows highlights the need of novel AGN-driven outflow models to comprehensively interpret these phenomena.
PRODIGE – envelope to disk with NOEMA
Authors: Hsieh T.-H. , Pineda J. E. , Segura-Cox D. M. , Caselli P. , Valdivia-Mena M. T. , Gieser C. , Maureira M. J. , Lopez-Sepulcre A. , Bouscasse L. , Neri R. , Möller Th. , Dutrey A. , Fuente A. , Semenov D. , Chapillon E. , Cunningham N. , Henning Th. , Piétu V. , Jimenez-Serra I. , Marino S. , Ceccarelli C.
Published: April 2024

Context. Complex organic molecules (COMs) have been found toward low-mass protostars, but the origins of the COM emission are still unclear. It can be associated with, for example, hot corinos, outflows, and/or accretion shock and disk atmospheres.

Aims. We aim to disentangle the origin of the COM emission toward the chemically rich protobinary system SVS13A using six O-bearing COMs.

Methods. We conducted NOrthern Extended Millimeter Array observations toward SVS13A as part of the PROtostars & DIsks: Global Evolution (PRODIGE) program. Our previous DCN observations reveal a possible infalling streamer, which may affect the chemistry of the central protobinary by inducing accretion outbursts and/or shocked gas. We further analyzed six O-bearing COMs: CH3OH, aGg’- (CH2OH)2, C2H5OH, CH2(OH)CHO, CH3CHO, and CH3OCHO. Although the COM emission is not spatially resolved, we constrained the source sizes to ≲0.3–0.4 arcsec (90–120 au) by conducting uv-domain Gaussian fitting. Interestingly, the high-spectral-resolution data reveal complex line profiles with multiple peaks; although the line emission is likely dominated by the secondary, VLA4A, at VLSR = 7.36 km s−1, the numbers of peaks (~2–5), the velocities, and the linewidths of these six O-bearing COMs are different. The local thermodynamic equilibrium (LTE) fitting unveils differences in excitation temperatures and emitting areas among these COMs. We further conducted multiple-velocity-component LTE fitting to decompose the line emission into different kinematic components. As a result, the emission of these COMs is decomposed into up to six velocity components from the LTE modeling. The physical conditions (temperature, column density, and source size) of these components from each COM are obtained, and Markov chain Monte Carlo sampling was performed to test the fitting results.

Results. We find a variety in excitation temperatures (100–500 K) and source sizes (D ~ 10–70 au) from these kinematic components from different COMs. The emission of each COM can trace several components, and different COMs most likely trace different regions.

Conclusions. Given this complex structure, we suggest that the central region is inhomogeneous and unlikely to be heated by only protostellar radiation. We conclude that accretion shocks induced by the large-scale infalling streamer likely exist and contribute to the complexity of the COM emission. This underlines the importance of high-spectral-resolution data when analyzing COM emission in protostars and deriving relative COM abundances.
Proper motion study of the 6.7 GHz methanol maser rings
Authors: Bartkiewicz A. , Sanna A. , Szymczak M. , Moscadelli L. , van Langevelde H. J. , Wolak P. , Kobak A. , Durjasz M.
Published: April 2024

Context. Methanol masers at 6.7 GHz are well-known signposts of high-mass star-forming regions. Due to their high brightness, they enable us to derive the three-dimensional gas kinematics near protostars and young stars.

Aims. We aim to understand the origin of the ring-like structures outlined by methanol maser emission in a number of sources. This emission could be, a priori, spatially associated with an outflow and/or disc around a high-mass protostar. In cases of expansion or rotation, maser proper motions should be, for instance, diverging from the ring centre or perpendicular to the ring radius.

Methods. Using sensitive, three-epoch observations spanning over 8 yr with the European VLBI Network, we have started the most direct investigations of maser rings using very accurate proper motion measurements with uncertainties below ~1 km s−1.

Results. We present full results for the five targets of our sample, G23.207−00.377, G23.389+00.185, G28.817+00.365, G31.047+00.356, and G31.581+00.077, where proper motions show similar characteristics; maser cloudlets do not move inwards towards the centre of the rings but rather outwards. We also include the most circular source, G23.657−00.127, in the discussion as a reference. The magnitude of maser proper motions ranges from a maximum of about 13 km s−1 to 0.5 km s−1. In two of the five sources with a high number of maser spots (>100), namely G23.207−00.377 and G23.389+00.185, we show that the size of the best elliptical model, fitted to the distribution of persistent masers, increases in time in a manner similar to the case of G23.657−00.127. Moreover, we checked the separations between the pairs of spots from distinct regions, and we were able to assess that G28.817+00.365 and G31.047+00.356 can be interpreted as showing expanding motions. We analysed the profiles of single maser cloudlets and studied their variability. Contrary to single-dish studies, the interferometric data indicate variability of the emission of single-masing cloudlets.

Conclusions. In five of the six targets, namely, G23.207−00.377, G23.389+00.185, G23.657-00.127, G28.817+00.365, and G31.047+00.356, expansion motions prevail. Only in the case of G31.581+00.077 can a scenario of disc-like rotation not be excluded. Complementary observations of thermal tracers as well as searching for ultra-compact H II regions in the same sources are needed. Although the overall morphology of the maser emission has remained stable, the intensities of individual maser cloudlets varied from epoch to epoch, suggesting internal instabilities.
Astrometric detection of a Neptune-mass candidate planet in the nearest M-dwarf binary system GJ65 with VLTI/GRAVITY
Authors:   GRAVITY Collaboration, Abuter R. , Amorim A. , Benisty M. , Berger J. P. , Bonnet H. , Bourdarot G. , Bourget P. , Brandner W. , Clénet Y. , Davies R. , Delplancke-Ströbele F. , Dembet R. , Drescher A. , Eckart A. , Eisenhauer F. , Feuchtgruber H. , Finger G. , Förster Schreiber N. M. , Garcia P. , Garcia-Lopez R. , Gao F. , Gendron E. , Genzel R. , Gillessen S. , Hartl M. , Haubois X. , Haussmann F. , Henning T. , Hippler S. , Horrobin M. , Jochum L. , Jocou L. , Kaufer A. , Kervella P. , Lacour S. , Lapeyrère V. , Le Bouquin J.-B. , Ledoux C. , Léna P. , Lutz D. , Mang F. , Mérand A. , More N. , Nowak M. , Ott T. , Paumard T. , Perraut K. , Perrin G. , Pfuhl O. , Rabien S. , Ribeiro D. C. , Sadun Bordoni M. , Shangguan J. , Shimizu T. , Stadler J. , Straub O. , Straubmeier C. , Sturm E. , Tacconi L. J. , Tristram K. R. W. , Vincent F. , von Fellenberg S. , Widmann F. , Wieprecht E. , Woillez J. , Yazici S. , Zins G.
Published: April 2024

The detection of low-mass planets orbiting the nearest stars is a central stake of exoplanetary science, as they can be directly characterized much more easily than their distant counterparts. Here, we present the results of our long-term astrometric observations of the nearest binary M-dwarf Gliese 65 AB (GJ65), located at a distance of only 2.67 pc. We monitored the relative astrometry of the two components from 2016 to 2023 with the VLTI/GRAVITY interferometric instrument. We derived highly accurate orbital parameters for the stellar system, along with the dynamical masses of the two red dwarfs. The GRAVITY measurements exhibit a mean accuracy per epoch of 50−60 ms in 1.5 h of observing time using the 1.8 m Auxiliary Telescopes. The residuals of the two-body orbital fit enable us to search for the presence of companions orbiting one of the two stars (S-type orbit) through the reflex motion they imprint on the differential A–B astrometry. We detected a Neptune-mass candidate companion with an orbital period ofp = 156 ± 1 d and a mass ofmp = 36 ± 7 M⊕. The best-fit orbit is within the dynamical stability region of the stellar pair. It has a low eccentricity,e = 0.1 − 0.3, and the planetary orbit plane has a moderate-to-high inclination ofi > 30° with respect to the stellar pair, with further observations required to confirm these values. These observations demonstrate the capability of interferometric astrometry to reach microarcsecond accuracy in the narrow-angle regime for planet detection by reflex motion from the ground. This capability offers new perspectives and potential synergies withGaiain the pursuit of low-mass exoplanets in the solar neighborhood.
The AstraLux-TESS high spatial resolution imaging survey
Authors: Lillo-Box J. , Morales-Calderón M. , Barrado D. , Balsalobre-Ruza O. , Castro-González A. , Mendigutía I. , Huélamo N. , Montesinos B. , Vioque M.
Published: April 2024

Context. Chance-aligned sources or blended companions can cause false positives in planetary transit detections or simply bias the determination of the candidate properties. In the era of high-precision space-based photometers, the need for high spatial resolution images has been demonstrated to be critical for validating and confirming transit signals. This already applied to theKeplermission, is now applicable to the TESS survey, and will be critical for the PLATO mission.

Aims. In this paper we present the results of the AstraLux-TESS survey, a catalog of high spatial resolution images obtained with the AstraLux instrument at the Calar Alto observatory (Almería, Spain) in the context of the TESS Follow-up Observing Program.

Methods. We used the lucky imaging technique to obtain high spatial resolution images from planet candidate hosts included mostly in two relevant regimes: exoplanet candidates belonging to the level one requirement of the TESS mission (planets with radiiR <4R⊕) and TESS planet candidates around intermediate-mass main-sequence stars.

Results. Among the 185 planet host candidate stars observed, we found 13 (7%) to be accompanied by additional sources within a separation of 2.2 arcsec. Among them, six are not associated with sources in theGaiaDR3 catalog, thus contaminating the TESS light curve. Even if no contaminants have been detected, we can provide upper limits and probabilities to the possible existence of field contaminants through the sensitivity limits of our images. Among the isolated hosts, we can discard hazardous companions (bright enough to mimic a planetary transit signals) with an accuracy below 1% for all their planets.

Conclusions. The results from this catalog are key to the statistical validation of small planets (prime targets of the TESS mission) and planets around intermediate-mass stars in the main sequence. These two populations of planets are difficult to confirm with the radial velocity technique because of the shallow amplitude of small planets and the high rotational velocities and low number of available spectral lines in the intermediate stellar mass regime. Our results also demonstrate the importance of this type of follow-up observation for future transit missions such as PLATO, even in theGaiaera.
Age of (152830) Dinkinesh I Selam constrained by secular tidal-BYORP theory
Authors: Merrill C. C. , Kubas A. R. , Meyer A. J. , Raducan S. D.
Published: April 2024

We constrained the age of the main belt binary asteroid system, (152830) Dinkinesh, through secular dynamics and assuming the secondary, Selam, is at equilibrium. We reproduced Selam’s current semi-major axis and rotation period and Dinkinesh’s current rotation period, starting from the initial conditions of the spin-up fission event. The method presented here includes the secular effects of YORP, BYORP, and tidal interactions, while also allowing for the strengths of these effects to be constrained. Based on this method, we performed a Monte Carlo simulation, which indicates that Selam’s age is likely to be ∼1–10 Ma. Derivations for improved equations that describe tidal-BYORP equilibria in binary asteroid systems are also presented in this work. In particular, we derived: (1) a tidal-BYORP equilibrium equation that scales appropriately with the secondary mass and accounts for differences in the primary and secondary densities; and (2) an equation for YORP-driven primary spin stability, with the secondary being at equilibrium.
The neutrino background from non-jetted active galactic nuclei
Authors: Padovani P. , Gilli R. , Resconi E. , Bellenghi C. , Henningsen F.
Published: April 2024

Aims. We calculate the contribution to the neutrino background from the non-jetted active galactic nuclei (AGN) population following the recent IceCube association of TeV neutrinos with NGC 1068.

Methods. We exploited our robust knowledge of the AGN X-ray luminosity function and evolution and converted it to the neutrino band by using NGC 1068 as a benchmark, together with a theoretically motivated neutrino spectrum.

Results. The resulting neutrino background up to redshift 5 does not violate either the IceCube diffuse flux or the upper bounds for non-jetted AGN, although barely so. This is consistent with a scenario in which the latter class makes a substantial contribution mostly below 1 PeV, while jetted AGN, that is, blazars, dominate above this energy, in intriguing agreement with the dip in the neutrino data at ∼300 TeV. More and better IceCube data on Seyfert galaxies will allow us to constrain the fraction of neutrino emitters among non-jetted AGN.
Unravelling the potential of fibrous silica zirconia catalyst for CO methanation in energy production
Authors: Hatta Abdul Hakim , Norazahar Norafneeza , Aziz Muhammad Akmal , Alhassan Mansur
Published: April 2024

In this contemporary era of rapid progress, the global demand for energy has reached unprecedented levels, placing considerable strain on existing energy supplies. To address this challenge, synthetic or substituted natural gas (SNG) has emerged as a groundbreaking energy source attained through the methanation reaction of hydrogen and carbon monoxide (CO). This paper unveils a successful synthesis method for fibrous silica zirconia (FSZr) exploiting the microemulsion procedure, subsequently applied in the CO methanation process. The catalyst underwent comprehensive characterization using advanced techniques, including Fourier Transform Infrared (FTIR) spectroscopy, Field-Emission Scanning Electron Microscopy (FESEM), x-ray diffraction (XRD), and N2 adsorption-desorption. The experimental results clearly demonstrate the exceptional catalytic performance of FSZr when compared to commercially available ZrO2. At a temperature of 500 ºC, FSZr achieved a CO conversion and CH4 yield of 20.76% and 11.52%, respectively. The remarkable achievements are credited to FSZr’s distinct fibrous structure, expansive surface area, and exceptional basic characteristics. The heightened surface area facilitates better access to reactive sites, while the strong basic properties enable easier adsorption of the reactant. These combined factors significantly enhanced the effectiveness of the CO methanation procedure. These findings underscore the significance of fibrous morphology in zirconia catalysts for CO methanation, presenting a promising avenue for further research and insights into meeting the global energy demands efficiently.
Effect of kenaf fiber loading on mechanical and morphological properties of polyurethane shape memory polymer composites
Authors: Khiyon Nor Hanim , Arshad Mohd Fadzil , Kamarudin Mohd Khairul , Muhammad Fauzi Nurshamimie
Published: April 2024

Shape memory polymers (SMPs) have captivated researchers and engineers with their unique ability to recover their original shape after deformation. Among SMPs, shape memory polyurethane (SMPU) is promising due to its easy processing, cost-effectiveness, and biocompatibility. Despite its potential, SMPU faces limitations in strength and modulus, hindering structural applications. This study investigates the sustainable improvement of shape memory polymer composites (SMPCs) by integrating kenaf fibers (KF) as a reinforcing material at different percentages, specifically 5%, 10%, 15%, 20%, 30%, and 40% of the composite’s weight. A combination of hand lay-up technique and compression moulding technique was employed for the fabrication process to achieve the desired shape. The results reveal a clear correlation between the KF content and the mechanical properties. Tensile testing reveals improved strength and strain up to 20% KF, peaking at this level but declining at 30% and 40% due to fiber agglomeration and void formation. Scanning electron microscope (SEM) analysis highlights favourable fiber-matrix adhesion at optimal level. By shedding light on the mechanical behaviour of SMPC with KF reinforcements, this study paves the way for developing high-performance composites tailored for shape memory applications.
Fabrication and characterization of highly hydrophobic PVDF membrane by phase inversion method with high anti-wettability characteristics
Authors: Enamul Hasan Muhammad , Md Nordin Nik Abdul Hadi , Shamsuddin Muhammad Rashid
Published: April 2024

Membrane gas-liquid separation technology has garnered significant attention in applications such as membrane desalination, distillation, and gas absorption due to its operational flexibility, compact design, and large specific interfacial area. However, the currently used membranes are prone to pore wetting under high operational pressures, transitioning from a non-wetted state to partially or fully wetted conditions. This undesired wetting increases mass transfer resistance for water vapor molecules, ultimately leading to reduced removal efficiency. To address this issue and enhance wetting resistance, membrane hydrophobicity needs to be improved. In this study, a highly hydrophobic polyvinylidene fluoride (PVDF) membrane was developed using the phase inversion method for membrane distillation applications. We mixed a 16wt% polymer concentration with N-Methylpyrrolidone (NMP) as a solvent at 50°C for 24 hours. Subsequently, the polymer solution was cast and exposed to different non-solvents, namely water and methanol, to investigate their impact. Surface morphology and hydrophobic properties of the synthesized membranes were analyzed using Scanning Electron Microscope (SEM) and a Goniometer. Our findings indicate that the PVDF membrane fabricated with methanol as the non-solvent exhibited a significantly higher water contact angle of 126°, compared to 70° when deionized water was used as the non-solvent. This change from water to methanol as the non-solvent resulted in a more symmetrical membrane structure, enhancing the water contact angle from 70° to 126°. It is interesting to note that increase in the water contact angle increases the hydrophobicity of the PVDF membrane.
Identifying Issues in the Katingan I Swamp Irrigation Area Through Field Survey and Monitoring Approaches
Authors: Hadi Siswoyo , Pratiwi Endita Prima Ari , Wignyosukarto Budi Santoso
Published: April 2024

The Katingan irrigation area is a swamp area that has undergone agricultural development. The optimization of yields necessitates the adaptation of management strategies in response to the challenges encountered within the swamp irrigation area. The objective of this study is to discern the issues in the Katingan I swamp irrigation area by conducting field surveys and monitoring. The field survey was conducted from December 2022 to March 2023. The primary data collected are water level, quality, agricultural products, and field documentation. Secondary data such as rainfall, irrigation network schemes, and institutions were also acquired. The survey result found water acidity issues due to water coming from peat forests and acid sulphate soils. The acidity of the water rises during low tide and when rain carries acidic water. There is a problem with high salinity, particularly during high tide in dry seasons. Optimal water management is achievable through continuous monitoring of water level and quality. Another issue is a lack of human resources to cultivate the land, especially because the irrigation service area has recently been expanded. The results of this study hopefully provide valuable insights for developing future management strategies in Katingan.
Optimizing the Integration of Building Information Modelling using Response Spectrum and Linear Time History Analysis. Case Study: Irregular Hangar Structure
Authors: Tohho Given , Sjah Jessica , Rarasati Ayomi Dita , Trigunarsyah Bambang
Published: April 2024

The increasing use of technology in the construction industry has introduced the concept of Building Information Modeling (BIM), which is widely utilized to streamline construction activities. BIM enables the exchange of data across various disciplines quickly, as well as facilitates analysis, design, and on-site construction processes. The implementation of BIM will be carried out in the analysis and design processes of structures with irregularities to assess the effectiveness and performance of BIM in modeling and analyzing structures. Considering the burgeoning development of the construction industry in Indonesia, there is a necessity for a laboratory hangar dedicated to conducting structural model tests and construction material examinations. The aim of this study is to compare the response and the volume output between the response spectrum and linear time history analysis of an irregular structure. The case study conducted in this research focuses on the 5-stories Laboratory Hangar in Indonesia. The software used in this study includes Autodesk Revit 2023 for BIM modeling and ETABS V21 for structural analysis. Data and model exchange are performed between both software platforms to evaluate the BIM integration between them.
Identification of Waste in The Production Process Using Lean Manufacturing Approach (Case Study: PT. Multiyasa Abadi Sentosa)
Authors: Fitriadi Ratnanto , Wijayanti Wahyu Retno
Published: April 2024

PT. Multiyasa Abadi Sentosa is an export company specializing in handmade crafts using natural materials such as banana fiber, rattan, and seagrass. The production process of baskets faces challenges such as rejected products, which slow down processing time, leading to shipment delays and increased production waste. This research aims to identify production activities, analyze waste, and propose improvements. The methods employed include Value Stream Mapping, Waste Assessment Model, and VALSAT. Research findings indicate that Value-Added activities contribute only 67.1%, while Non-Value Added and Necessary but Non-Value Added activities are also significant. Process Cycle Efficiency is 67%. The largest sources of waste are defects in products and transportation. Implementing Quality Control for raw materials and optimizing transportation are proposed solutions to reduce waste.