bluuebunny/crossref_metadata_2025 huggingface dataset:
Climate change, counter-terrorism and capitalist development in Somalia
Authors: Mueller Jason C.
Published: September 2023

Somalia is often referred to as a ‘failed state’. In addition to ineffective governance, feeble economic development, and a large anti-government insurgency, it faces increasingly severe climate change-induced devastation. This article offers a critical discussion of the role of capitalist interests and ideology as a factor in the climate crisis. It explores interlocking issues of (1) the relationship between the ruling political class of Somalia and capitalist mining interests; (2) the largely covert US-backed ‘war on terror’ in Somalia; and (3) the ongoing, capitalism-induced climate crisis. The article analyses current US and Somali proposals to address these issues. Many of these proposals remain trapped in the politico-ideological deadlock of capitalist developmentalism, oriented towards fossil fuel extraction and militarised accumulation. The trajectory of this current path in Somalia is leading to immiseration, oppression, displacement for millions of people, and the destruction of an already deteriorating environment. Alternative paths to avert these catastrophes require transnational solidarity, cooperation and assistance.
On staticity of bifurcate Killing horizons*
Authors: Chruściel Piotr T , Mars Marc
Published: September 2023

We show that bifurcate Killing horizons with closed torsion form, in spacetimes of arbitrary dimension, and satisfying a Ricci-structure condition arise from static Killing vectors. The result applies in particular to Λ-vacuum spacetimes.
Pressure gradient in an incompressible fluid as a reaction force and the preservation of the principle of ‘cause and effect’
Authors: Simeonov Lachezar S
Published: September 2023

When considering the motion of an incompressible fluid, it is common practice to take the curl on both sides of the Navier–Stokes (or Euler) equations and cancel the pressure force. The governing equations are sufficient to derive the velocity field of the fluid without any knowledge of the pressure. In fact, the pressure is only calculated after obtaining the velocity field. This raises a number of conceptual problems. For instance, why is the pressure unnecessary for obtaining the velocity field? Traditionally, forces have been considered as the ‘causes’ of motion, and the resulting acceleration as the ‘effect’. However, the acceleration (the effect) and the resulting velocity field can be obtained without any recourse to the pressure (the cause), seemingly violating the principle of ‘cause’ and ‘effect’. We address these questions by deriving the pressure force of an incompressible fluid, starting from d’Alembert’s principle of virtual work, as a ‘reaction force’ that maintains the incompressibility condition. Next, we show that taking the curl on both sides of the Navier–Stokes (or Euler) equations is equivalent to using d’Alembert’s principle of virtual work, which cancels out the virtual work of the pressure gradient. This shows that abstract procedures, such as taking the curl on both sides of an equation, can actually be tacit applications of rich physical principles, without one realizing it. This can be quite instructive in a classroom of undergraduate students.
From Galilean relativity to special relativity: the pedagogical contribution of the space-proper time diagrams
Authors: Kirèche Alain
Published: September 2023

After detailing the characteristics of space-proper time diagrams for Galilean relativity and special relativity, we show how they can be used to better visualize the progression of ideas about the absolute or relative nature of space and time, from Galilean relativity to special relativity. We conclude that space-proper time diagrams could be an interesting new tool for introducing special relativity.
Mittag–Leffler expansions for inverse spectral problems with mixed data
Authors: Wei Zhaoying , Wei Guangsheng
Published: September 2023

We consider the inverse spectral problem for the Sturm–Liouville problem in the interval

[
0
,
1
]

with the Dirichlet boundary conditions at both ends. We provide a method for the unique reconstruction of the potential that is known a priori on the subinterval

[
0
,
r

/

m
]

, where m and r being positive integers and satisfying

r
<
m

/

2

, by using the spectral data set consisting of all the eigenvalues and a subset of the norming constants. The method is based on the Mittag–Leffler decomposition which can help us to decompose an entire function of exponential type into two functions of smaller types. This decomposition allows the use of Lagrange interpolation in order to reconstruct the potential in the Sturm–Liouville problem. We also provide necessary and sufficient conditions related to the existence issues.
Highly-sensitive expandable microsphere-based flexible pressure sensor for human–machine interaction
Authors: Wang Ye , Duan Shengshun , Liu Jiachen , Zhao Fangzhi , Chen Pinzhen , Shi Qiongfeng , Wu Jun
Published: September 2023

Flexible microstructural pressure sensors (FMPSs) have been widely used in different areas including health monitoring, human–machine interaction and electronic skin for their good reliability, easy fabrication, and highly sensitive sensing performance. Although the use of a sensing layer with microstructure improves the sensor sensitivity, it also results in limited sensitive pressure range, slow response and poor cyclic stability, which prevents the sensors from being utilized in applications requiring wide detect range, real-time response and high durability. Here, we propose an advanced micro-structured sensing layer through doping thermally expandable microspheres into the screen-printing carbon black slurry to enhance its mechanical properties. An FMPS is then developed based on this enhanced micro-structured sensing layer. Benefiting from the expanded microsphere-like microstructure, the as-prepared sensor features high sensitivity (37.16 kPa−1), fast response/recovery time (126/52 ms), and good mechanical stability (over 3000 cycles). In addition, a home-made and effective collision avoidance system consisting of a robotic arm, the pressure sensor, a MEGA2560 microcontroller unit and a computer is constructed to indicate the sensor’s outstanding tactile perception characteristic, making it a promising candidate for intelligent robotic applications such as human–robot collaboration. Furthermore, we develop a pressure sensor array and demonstrate its ability to spatial pressure distribution perception. The developed microsphere-based pressure sensor and its array show great potential to be adopted in various monitoring and interactive applications such as humanoid robots, smart home, human–machine interaction, etc.
Hyperfine transition induced by atomic motion above a paraffin-coated magnetic film
Authors: Sekiguchi Naota , Usui Hiroaki , Hatakeyama Atsushi
Published: September 2023

We measured transitions between the hyperfine levels of the electronic ground state of potassium-39 atoms (transition frequency: 460 MHz) as the atoms moved through a periodic magneto-static field produced above the magnetic-stripe domains of a magnetic film. The period length of the magnetic field was 3.8 µm. The atoms were incident to the field as an impinging beam with the most probable velocity of 550 m s−1 and experienced a peak oscillating field of 20 mT. Unwanted spin relaxation caused by the collisions of the atoms with the film surface was suppressed by the paraffin coating on the film. We observed increasing hyperfine transition probabilities as the frequency of the field oscillations experienced by the atoms increased from 0 to 140 MHz for the atomic velocity of 550 m s−1, by changing the incident angle of the atomic beam with respect to the stripe domains. Numerical calculation of the time evolution of the hyperfine states revealed that the oscillating magnetic field experienced by the atoms induced the hyperfine transitions, and the main process was not a single-quantum transition but rather multi-quanta transitions.
Deep learning assisted microwave-plasma interaction based technique for plasma density estimation
Authors: Ghosh Pratik , Chaudhury Bhaskar , Purohit Shishir , Joshi Vishv , Kothari Ashray , Shetranjiwala Devdeep
Published: September 2023

The electron density is a key parameter to characterize any plasma. Most of the plasma applications and research in the area of low-temperature plasmas (LTPs) are based on the accurate estimations of plasma density and plasma temperature. The conventional methods for electron density measurements offer axial and radial profiles for any given linear LTP device. These methods have major disadvantages of operational range (not very wide), cumbersome instrumentation, and complicated data analysis procedures. The article proposes a deep learning (DL) assisted microwave-plasma interaction-based non-invasive strategy, which can be used as a new alternative approach to address some of the challenges associated with existing plasma density measurement techniques. The electric field pattern due to microwave scattering from plasma is utilized to estimate the density profile. The proof of concept is tested for a simulated training data set comprising a low-temperature, unmagnetized, collisional plasma. Different types of symmetric (Gaussian-shaped) and asymmetrical density profiles, in the range 1016–1019 m−3, addressing a range of experimental configurations have been considered in our study. Real-life experimental issues such as the presence of noise and the amount of measured data (dense vs sparse) have been taken into consideration while preparing the synthetic training data-sets. The DL-based technique has the capability to determine the electron density profile within the plasma. The performance of the proposed DL-based approach has been evaluated using three metrics- structural similarity index, root mean square logarithmic error, and mean absolute percentage error. The obtained results show promising performance in estimating the 2D radial profile of the density for the given linear plasma device and affirms the potential of the proposed machine learning-based approach in plasma diagnostics.
Anisotropic optical conductivities of model topological nodal-line semimetals
Authors: Kandel Sita , Gumbs Godfrey , Berman Oleg L
Published: September 2023

With the use of simple models, we investigated the optical conductivity of a nodal-line semimetal (NLSM) whose crossing of the conduction and valence bands near the origin (O point) in the (

k
x

,

k
y

) plane of a small cubic region can be adjusted by a parameter α. The Hamiltonian of the NLSM is based on the

k

⋅

p

model for the low-lying energy bands. When α = 0, these bands touch each other along a continuous closed loop but the opening of a band gap corresponding to finite values of α and the varying of the carrier concentration can be adjusted. This provides a tunable semiconductor gap, around the O point and the valence and conduction bands can meet at a pair of points within the small cubic region in k space. The optical conductivity of such a NLSM is calculated using the Kubo formula with emphasis on the optical spectral weight redistribution, deduced from appropriate Green’s functions, brought about by changes in gap and chemical potential due to modifying α. We derived closed-form semi-analytic expressions for the longitudinal components of the optical conductivity for these model systems of NLSM and compare results for chosen α and chemical potential. We also present results for the heat capacity when the system is in thermal equilibrium for various chosen α and chemical potential.
Bearing fault diagnosis under non-stationary conditions based on a speed signal resonance component demodulation algorithm
Authors: Ye Ming , Zhang Xiaojun , Yang Jiaqiang
Published: September 2023

This paper proposes a novel bearing fault diagnosis indicator, the resonance component, for motor speed signals. The speed signal was modulated into a higher-frequency band using a double-inertia system, and the bearing fault information was carried and reserved in this high-frequency resonance component. Variational mode decomposition was then used to separate the components unrelated to the resonance based on the parameters optimized using the artificial bee colony algorithm. After envelope demodulation and angular resampling, the multipoint optimal minimum entropy deconvolution adjusted algorithm was utilized to enhance the amplitude of the order spectrum at the corresponding faulty order. Additionally, experiments were successfully conducted on both the outer and inner raceway bearing faults under time-varying conditions using the proposed method. The results indicate that the ordinary diagnosis method using the basic bearing fault characteristic frequency as an indicator is less effective.
Parametric study of intensity-ratio-based phosphor thermometry using Mg4FGeO6:Mn4+ for instantaneous temperature measurement
Authors: Cheng Weilun , Liu Yingzheng , Peng Di
Published: September 2023

Intensity-ratio-based phosphor thermometry is advantageous for instantaneous temperature measurement because it avoids interframe displacement due to moving phosphor coated samples that is encountered with lifetime-based methods. This study was aimed at investigating the effects of exposure time, excitation energy, and wavelength on intensity-ratio-based phosphor thermometry using Mg4FGeO6:Mn4+ (MFG). First, the temperature-dependent emission spectra of MFG were obtained under 355 nm and 405 nm excitations. The spectra exhibited different trends in the two cases, potentially because of thermally enhanced phonon-assisted absorption. Next, the shot-to-shot calibration uncertainties were evaluated from the temperature calibration results under different exposure time and excitation irradiance/fluence values for light-emitting diode/laser. The uncertainties under 355 nm and 405 nm excitations exhibited similar trends, i.e. they increased and decreased with increasing temperature and exposure time, respectively. For the minimum exposure time of 4 μs under 355 nm excitation, the uncertainty increased from 1.5 K at 323 K to 3.3 K at 673 K at a constant excitation fluence of 3.14 mJ cm−2. The uncertainties under 405 nm excitation were higher than those under 355 nm excitation. In addition, the inaccuracies due to excitation non-uniformity were evaluated from the calibration results under different excitation irradiance/fluence. The calibration curves were more sensitive to excitation irradiance at higher temperatures under 405 nm excitation. Consequently, the excitation non-uniformity induced inaccuracies under 405 nm excitation and different exposure time values were small at low temperatures (0.4–1.1 K at 323 K) and increased rapidly with temperature (2.6–14.4 K at 673 K). In the case of 355 nm excitation, the calibration curves exhibited small sensitivity to excitation fluence only at low temperatures. As the temperature increased, the inaccuracies under 355 nm excitation decreased and then increased, and exhibited values between 0.5 K and 2.5 K.
Fault diagnosis of gas turbine generator bearings using enhanced valuable sample strategy and convolutional neural network
Authors: Xu Xiaozhuo , Li Zhiyuan , Zhao Yunji , Qian Wei
Published: September 2023

Gas turbine bearings operate continuously under complex and harsh conditions such as high temperatures, high pressures and high speeds. Bearing fault monitoring data often exhibits anomalies, noise, missing values, and strong coupling and non-linearity due to real-world random factors. In addition, the traditional convolutional neural network (CNN) is still limited by the scarcity of labeled samples in real-world conditions and cannot fully extract fault features. To address the complexities of strongly coupled fault data, inconsistent data quality, and the shortage of authentic labeled samples, this paper presents a novel method for bearing fault diagnosis. This method utilizes an enhanced valuable sample strategy in conjunction with CNNs, integrating data enhancement and active learning (AL) for preprocessing to create valuable training sets for the networks. At the outset, random dropout and scaling jitter operations are applied to the original data, effectively removing anomalies and gaps in the fault signals. This process simultaneously emulates variations in the frequency spectrum and amplitude of vibration signals under real operating conditions, thereby enhancing the quality of gas turbine bearing fault data. Subsequently, the method incorporates AL techniques, iteratively selecting unlabeled data samples with the highest information value, and annotating them using support vector machines. This strategy creates a valuable training dataset that further enhances the fault diagnosis capabilities of the model. In the subsequent phase, a three-dimensional CNN is employed to extract fault feature information efficiently from the fault data, culminating in precise fault classification. In order to validate the effectiveness and superiority of the algorithm, validation and comparison analyses were carried out using the Case Western Reserve University and XJTU open datasets. To evaluate the practical effectiveness, a gas turbine main bearing dataset collected in a real environment, named the BaiChuan dataset, is used for the engineering validation of the proposed method.
Isodrastic magnetic fields for suppressing transitions in guiding-centre motion
Authors: Burby J W , MacKay R S , Naik S
Published: September 2023

In a magnetic field, transitions between classes of guiding-centre motion can lead to cross-field diffusion and escape. We say a magnetic field is isodrastic if guiding centres make no transitions between classes of motion. This is an important ideal for enhancing confinement. First, we present a weak formulation, based on the longitudinal adiabatic invariant, generalising omnigenity. To demonstrate that isodrasticity is strictly more general than omnigenity, we construct weakly isodrastic mirror fields that are not omnigenous. Then we present a strong formulation that is exact for guiding-centre motion. We develop a first-order treatment of the strong version via a Melnikov function and show that it recovers the weak version. The theory provides quantification of deviations from isodrasticity that can be used as objective functions in optimal design. The theory is illustrated with some simple examples.
Characterization of Cherenkov imaging parameters and positional constraints on an O-ring linear accelerator
Authors: Alexander Daniel A , Majji Srikanth , Jermyn Michael , Byrd Brook K , Bruza Petr , Li Taoran , Zhu Timothy C
Published: September 2023

Objective. With the introduction of Cherenkov imaging technology on the Halcyon O-ring linear accelerator platform, we seek to demonstrate the imaging feasibility and optimize camera placement. Approach. Imaging parameters were probed by acquiring triggering data Cherenkov image frames for simplistic beams on the Halcyon and comparing the analyzed metrics with those from the TrueBeam platform. Camera position was analyzed by performing 3D rendering of patient treatment plans for various sites and iterating over camera positions to assess treatment area visibility. Main results. Commercial Cherenkov imaging systems are compatible with the pulse timing of the Halcyon, and this platform design favorably impacts signal to noise in Cherenkov image frames. Additionally, ideal camera placement is treatment site dependent and is always within a biconical zone of visibility centered on the isocenter. Visibility data is provided for four treatment sites, with suggestions for camera placement based on room dimensions. Median visibility values were highest for right breast plans, with values of 80.33% and 68.49% for the front and rear views respectively. Head and neck plans presented with the lowest values at 26.44% and 38.18% respectively. Significance. This work presents the first formal camera positional analysis for Cherenkov imaging on any platform and serves as a template for performing similar work for other irradiation platforms. Additionally, this study confirms the Cherenkov imaging parameters do not need to be changed for optimal imaging on the Halcyon. Lastly, the presented methodology provides a framework which could be further expanded to other optical imaging systems which rely on line of sight visibility to the patient.
An ensemble approach for enhancing generalization and extendibility of deep learning facilitated by transfer learning: principle and application in curing monitoring
Authors: Zhu Jianjian , Su Zhongqing , Han Zhibin , Lan Zifeng , Wang Qingqing , Ho Mabel Mei-po
Published: September 2023

Machine learning (ML) and deep learning (DL) have exhibited significant advantages compared to conventional data analysis methods. However, the limitations of poor generalization and extendibility impede the broader application of these methods beyond specific learning tasks. To address this challenge, this study proposes a transfer learning-based ensemble approach called SMART. This approach incorporates synthetic minority oversampling technique, average reinforced interpolation, series data imaging, and fine-tuning. To validate the effectiveness of SMART, we conduct experiments on curing monitoring of polymeric composites and construct a hybrid dataset with highly heterogeneous features. We compare the performance of SMART with exemplary ML algorithms using conventional evaluation indicators, including Accuracy, Precision, Recall, and F1-score. The experimental results demonstrate that the SMART approach exhibits superior generalization capacity and extendibility, achieving indicator scores above 0.9900 in new scenarios. These findings suggest that the proposed SMART approach has the potential to break through the limitations of conventional ML and DL models, enabling wider applications in the industrial sectors.
Levy-type analytical series solution for the three-dimensional free vibrations of functionally graded material rectangular plates with piezoelectric layers
Authors: Huang Chiung-Shiann , Chen Guan-Hong , Lu Meng-Wei
Published: September 2023

Analytical solutions founded on three-dimensional theories play a crucial role in evaluating the credibility and precision of different plate theories and numerical methodologies. While Levy-type analytical solutions are widely recognized, they have been primarily confined to purely elastic plates. This study introduces a Levy-type analytical series solution for three-dimensional vibrations in a sandwich rectangular plate featuring a functionally graded material (FGM) core, along with piezoelectric material (PM) layers on the top and bottom surfaces. The behaviors of the FGM and PM layers were described using three-dimensional elasticity and piezoelasticity theories, respectively. In this study, the displacement functions and electric potential of each layer were expanded by Fourier series and polynomial auxiliary functions. An analytical series solution was then established by satisfying the governing equations of each layer, the mechanical and electric boundary conditions on the six faces of the plate, and the continuity conditions on the interfaces between the PM and FGM layers. To validate the proposed solutions, in-depth convergence studies were conducted for the vibration frequencies of the first six modes of sandwich square plates with various boundary conditions on the other pair of side faces. The well-converged results were then compared with published data based on various plate theories to verify the accuracy of these published data. Finally, accurate nondimensional frequencies were tabulated for the first six modes of sandwich rectangular plates with various aspect ratios, thickness-to-width ratios, PM-to-FGM layer thickness ratios, power law indices for the FGM layer, and six combinations of boundary conditions. These new numerical results when piezoelectric coupling is considered should be very useful to future analytical and numerical studies.
Research on interactions between different operating modes of piezoelectric motors
Authors: Li Chong , Chen Ruimin
Published: September 2023

This paper explores interactions between multiple operating modes of piezoelectric motors. The developed motor can operate in the second-order in-plane bending modes (I), the third-order in-plane bending modes (II) and the first-order out-of-plane bending modes (III). These working modes excited separately and simultaneously, can be manipulated electronically. Each of the vibrational modes can both be driven by applying single-phase and two-phase voltages to piezoelectric ceramic plates. In order to produce all the vibration states, the structural parameters of stator were strictly designed to harmonize two eigenfrequencies of each type of vibrational modes by using finite element software ANSYS. Displacement characteristics of stator driving particles under all vibration states were calculated to evaluate mutual effects of different operating modes. Simulation results reveal that the superposition of I and II corresponds to a mode with lower resonance frequency and larger vibration amplitude in stator body. For the designed motor, the conjunction of modes I and II actually forms the first-order in-plane vibrational mode B01. Therefore, the response displacement of stator driving points reaches the maximum value when modes I and II are conjointly actuated by supplying single-phase excitation voltage under the premise of undistorted three-dimensional motion trajectory. The motor performances under that condition were also investigated experimentally. The dimension of the fabricated prototype motor is 10 mm × 10 mm × 20 mm. The stall torque is 0.2 N·m under 200 V single-phase excitation, when the motor operates in modes I and II simultaneously. The maximum no-load speed is 74 r min−1. Compared with separate actuation of vibrational modes I and II, mechanical properties of the prototype motor are significantly improved.
Self-centering capacity of RC columns with smart plastic hinges of martensitic NiTi SMA bars
Authors: Choi Eunsoo , Jeon Jong-Su , Lee Jong-Han
Published: September 2023

The objective of this study was to examine the self-centering capacity of reinforced concrete (RC) columns with martensitic shape memory alloy (SMA) bars in the plastic hinge region. To achieve this, three RC columns were prepared: one was conventional and the other two had SMA bars in the plastic hinge zone. The columns had a diameter of 400 mm, height of 1400 mm, and aspect ratio of 3.5. The 400 mm long SMA bars were connected to the steel rebars using specially devised couplers. A cyclic lateral load was applied at the top of the columns, and the lateral displacements along the height of the columns and the corresponding forces were measured during cyclic lateral loading. The strain in the SMA bars was also measured. The RC column with SMA bars exhibited a plastic hinge around the couplers, thus concrete damage from cracking was concentrated at this site. This was completely different from the failure mode of the conventional RC column. The SMA bars in the column were in an elastic state, whereas the steel rebars yielded inside the couplers. The RC column with SMA bars exhibited excellent self-centering capacity, and its displacement recovery ratio was approximately 95% at a drift of 5%. However, its energy-dissipation capacity was lower than that of the conventional RC column. The equivalent damping ratio of the RC column with SMA bars was approximately 3% after 1.75% drift. It is conjectured that the excellent self-centering of the RC column with SMA bars was caused by the elastic behavior of the martensitic SMA bars.
Determining the access to H–mode in the ITER pre–fusion and fusion power operation phases at low plasma current with full–radius TGLF–SAT2 simulations of L–mode plasmas
Authors: Angioni C. , Citrin J. , Loarte A. , Polevoi A.R. , Kim S.H. , Fable E. , Tardini G.
Published: September 2023

The pre–fusion power operation 1 phase of ITER is planned to be characterized by electron cyclotron resonance heating only. Under the assumption that the access to H–mode is determined by a critical ion heat flux at the plasma edge, full–radius ASTRA simulations with the TGLF–SAT2 transport model are performed in order to compute the ion heat flux produced by the thermal exchange between electrons and ions in different operational conditions. Both hydrogen and deuterium plasmas at 5 MA are considered, respectively at 1.8 T and 2.65 T, corresponding to one third and half of the nominal maximum magnetic field. Different levels of electron cyclotron heating power are considered in sets of simulations with increasing values of the electron line averaged density. The predictions are compared with the currently available scaling of the critical ion heat flux. In hydrogen, 20 MW of electron heating power are predicted to allow H–mode access in a vanishingly small density window, whereas 30 MW and 40 MW would allow more substantial H–mode operational windows. Despite the fact that in deuterium plasmas the thermal exchange between electrons and ions is smaller by the hydrogen to deuterium mass ratio compared to hydrogen plasmas, the lower H–mode power threshold in deuterium leads to the prediction that an even broader and more robust domain to access H–mode is obtained at half field at 40 MW in deuterium as compared to operation in hydrogen at one third of the maximum magnetic field, even at the same power.
Trapping and Repellent Techniques for Huanglongbing Management in Citrus Orchards: Innovative Strategies to Combat Vector-Mediated Disease Transmission
Authors: Poerwanto M E
Published: September 2023

The global increase in human population has heightened the demand for citrus fruits and their derivatives, necessitating effective management strategies to mitigate the impact of huanglongbing (HLB) disease. Caused by gram-negative bacteria such as ‘Candidatus Liberibacter asiaticus’, ‘Candidatus Liberibacter africanus’, and ‘Candidatus Liberibacter americanus’, HLB is primarily transmitted by the insect vector Diaphorina citri. While traditional vector suppression methods using insecticides have proven ineffective, innovative approaches are required to control disease spread. This study aims to address the persistent nature of the vector and its ability to transmit HLB throughout its life cycle by emphasizing trapping and repellent techniques. By implementing early detection methods, utilizing disease-resistant citrus varieties, employing disease-free seeds, enhancing nutritional regimes, and reducing vector populations, promising results have been achieved in reducing vector populations and limiting HLB inoculum. The implications of this research underscore the importance of adopting trapping and repellent strategies, alongside the use of disease-free citrus plants, to effectively manage HLB and safeguard citrus plantations worldwide.
Impact of Pipe Length on Discharge and Headloss in PVC Water Pipe Installations
Authors: Mustofa W A , Tjahjanti P H
Published: September 2023

This study was conducted to investigate the implications of pipe length on water discharge and headloss in clean water pipe installations in Klampok hamlet, Indonesia. Three residential houses were selected as research sites, each equipped with a 2-inch diameter PVC type pipe and a water pump with a power of 3.6 housepower. The goal was to measure the water discharge, major and minor headloss, and the flow pattern within these pipe installations. Results revealed a water pump discharge to the reservoir of 0.004 m3/s, while the reservoir water discharge designated to supply residents’ houses was 0.0026 m3/s. Further, the study uncovered that headloss value was inversely proportional to pipe length, with a maximum major headloss value of 1.764 m at 17 m and a minimum of 1.038 m at 10 m, similarly mirrored in minor headloss values. Finally, the flow pattern within the pipe, irrespective of its length, was found to be turbulent, as deduced from the Reynolds number (Re=165,780 > 4,000). These findings underscore the role of pipe length in dictating energy loss and water discharge rates, offering key insights for the design and installation of efficient water supply systems.
Sustainable Bioavtur: A System Dynamics Approach to Addressing the Aviation Industry’s Environmental Impact
Authors: Nuryadin D , Nurcholis M , Rahmanda G A
Published: September 2023

The global energy crisis, predominantly affecting fossil fuel sources, poses significant challenges to numerous sectors worldwide, leading to escalating fuel prices and rising costs of living and production. The aviation industry, in particular, faces severe repercussions as domestic avtur production fails to meet the soaring demand, jeopardizing economic profitability and energy security. To tackle these issues, this study employs a qualitative modeling approach using system dynamics to investigate the interconnections among social, economic, technological, and environmental components within the biofuels development system. The research highlights the urgency of implementing several measures, including land conversion restrictions, regulation of palm oil trade schemes, and technological advancements in bioavtur production in Indonesia, to mitigate potential adverse consequences. The findings underscore the aviation industry’s contribution to greenhouse gas emissions and emphasize the need for sustainable biovehicles. This study provides valuable insights for policymakers, scientists, and professionals in the agricultural environment, ecology, and resources field, offering strategies to address the aviation sector’s environmental impact while ensuring sustainable energy alternatives.
Inorganic Waste Management and Energy Potential: Implications for Agricultural Sustainability
Authors: Dharmasyah D F , Anasstasia T T , Utami A , Widiarti I W , Alfiani O D
Published: September 2023

This study aims to evaluate the potential of inorganic waste as an energy source at TPS 3R Kasih (Indonesian waste management facility), a waste management site currently facing challenges with effective solid waste segregation. A comprehensive assessment was performed by analyzing heap size, waste composition, density, and energy potential through proximate and ultimate tests. The findings revealed that the site generates an average of 12.34 tons of waste per week, with inorganic waste accounting for 23.28%. Further examination of this inorganic waste, comprising of Hard Plastic (3.18%), Ordinary Plastic (10.97%), Paper/Carton (6.84%), Rubber/Fabric (3.65%), and Wood (2.30%), indicated its significant potential as Refuse Derived Fuel (RDF) fluff. Upon processing, the RDF fluff presented a calorific value of 4,708 Kcal/kg, Moisture of 2.1%, Ash Content of 3.7%, and Volatile Matter of 85.2%. These characteristics make it a potential alternative fuel source for the cement industry. The study concludes that effective waste segregation and processing at TPS 3R Kasih could transform inorganic waste into a valuable energy source, highlighting the significant implications for waste-to-energy strategies and the reduction of dependency on fossil fuels.
UK scientists dismayed by stalled Horizon progress
Authors: Allen Michael
Published: September 2023

Scientists have expressed their disappointment at the lack of progress in negotiations over the UK re-joining the €95bn Horizon Europe research programme.
Euclid dark-energy mission launches
Authors: Banks Michael
Published: September 2023

The €1.4bn Euclid mission was launched last month to study the large-scale structure of the universe and understand how it evolved following the Big Bang.
Investing in innovation
Authors: Johnston Hamish
Published: September 2023

Physicist and creativity coach Dennis Sherwood gives Hamish Johnston his top tips on generating novel ideas and stimulating creativity in science.
Approaching infinity, and beyond
Authors: Viti Eugenia , Viti Ivan
Published: September 2023

Brother-and-sister duo Eugenia Viti and Ivan Viti ponder the limits of the everyday.
Air quality monitor detects coronavirus in near real time
Authors: Dumé Isabelle
Published: September 2023

A new air quality monitor can detect any variant of the SARS-CoV-2 virus in near real time, and could be adapted to detect other respiratory pathogens.
Why fungi could hold the key to eco-friendly, fire-resistant buildings
Authors: Harris Margaret
Published: September 2023

Materials researchers are exploring ways to weave fungus into the fabric of buildings as inexpensive replacements for foams, timber and plastics due to their excellent thermal and acoustic properties.
LK-99 fails replication test
Authors: Harris Margaret
Published: September 2023

Independent groups find no evidence for room-temperature, ambient-pressure superconductivity in a modified form of lead apatite dubbed LK-99, as Margaret Harris reports.
Where credit’s due
Authors: McKenzie James
Published: September 2023

R&D tax credits can help to keep hi-tech firms afloat, which is why James Mckenzie welcomes a new plan to make the system in the UK much less complex.
Writing memorials
Authors: Crease Robert P
Published: September 2023

Robert P Crease explains why “biographical memoirs” are so tricky to get right.
Cold: the early days of laser cooling
Authors: Orzel Chad
Published: September 2023

The advent of laser cooling revolutionized the field of atomic physics, transforming atomic clocks and GPS technology and laying the foundations for quantum computing with atoms and ions. In the first of a three-part series, Chad Orzel tells the story of its early years.
Engineering materials that could change the world
Authors: Hiscott Laura
Published: September 2023

2022 Europhysics Prize and Hamburg Prize for Theoretical Physics winner Nicola Spaldin talks to Laura Hiscott about her work on magnetoelectric multiferroics, the importance of finding fun in research and how physics can benefit from a more flexible idea of excellence.
Proof of the Kresch-Tamvakis conjecture
Authors: Caughman John , Terada Taiyo
Published: September 2023

In this paper we resolve a conjecture of Kresch and Tamvakis [Duke Math. J. 110 (2001), pp. 359–376]. Our result is the following.

Theorem: For any positive integer

D
D

and any integers

i
,
j

i,j

(
0
≤
i
,
j
≤
D
)
,

(0\leq i,j \leq D), \;

the absolute value of the following hypergeometric series is at most 1:

4

F
3

[

−
i
,

i
+
1
,

−
j
,

j
+
1

1
,

D
+
2
,

−
D

;
1
]

.

\begin{equation*} {_4F_3} \left [ \begin {array}{c} -i, \; i+1, \; -j, \; j+1 \\ 1, \; D+2, \; -D \end{array} ; 1 \right ]. \end{equation*}

To prove this theorem, we use the Biedenharn-Elliott identity, the theory of Leonard pairs, and the Perron-Frobenius theorem.
Model theoretic characterizations of large cardinals revisited
Authors: Boney Will , Dimopoulos Stamatis , Gitman Victoria , Magidor Menachem
Published: September 2023

In Boney [Israel J. Math. 236 (2020), pp. 133–181], model theoretic characterizations of several established large cardinal notions were given. We continue this work, by establishing such characterizations for Woodin cardinals (and variants), various virtual large cardinals, and subtle cardinals.
Patients with AUD exhibit dampened heart rate variability during sleep as compared to social drinkers
Authors: Wemm Stephanie E , Golden Max , Martins Jorge , Fogelman Nia , Sinha Rajita
Published: September 2023

Chronic heavy alcohol use profoundly affects the cardiovascular system, contributing to several life-threatening cardiovascular diseases. Heart rate variability (HRV), or the fluctuations in heart rate, reflects dynamic autonomic nervous system processes that change to meet biological demands and environmental challenges. In the current study, we examined whether HRV metrics are altered in alcohol use disorder (AUD) during waking and sleeping with passive biomonitoring as participants went about their daily lives. Social drinkers (standard deviation: n = 10, 5 female) and treatment-seeking individuals with moderate to severe AUD (n = 16, 7 female) provided continuous, real-world heart rate monitoring for 5 days of monitoring on average (M = 5.27 ± 2.22). Five indices of respiration and HRV—respiratory sinus arrhythmia (RSA) amplitude, high frequency (HF), low frequency (LF), HF/LF ratio, root-mean-square standard deviation (RMSSD), and standard deviation of the N–N intervals (SDNN)—were analyzed separately for waking and sleeping hours. Both RMSSD and SDNN decreased the longer the participants were awake (Ps < .013). During sleeping hours, HF, RSA amplitude, RMSSD, and SDNN were significantly higher in light social drinkers as compared to patients with AUD (all Ps < .009), indicating higher parasympathetic activation during sleep in the SD versus AUD group. Sleep and waking HRV measures were significantly correlated with patient-reported symptoms of depression and sleep difficulties in the AUD group (Ps < .05). This natural observational study utilizing continuous autonomic biomonitoring in the real world indicates parasympathetic dysfunction that is clearly detectable during sleep in AUD and HRV measures, which are also related to clinical, patient-related symptoms of AUD.
Pollination syndromes and the origins of floral traits
Authors: Assis Leandro C S
Published: September 2023

Background

A general view in the study of pollination syndromes is that floral traits usually represent convergent floral adaptations to specific functional pollinator groups. However, the definition of convergence is elusive and contradictory in the literature. Is convergence the independent evolution of either the same trait or similar traits with the same function? A review of the concept of convergence in developmental biology and phylogenetic systematics may shed new light in studies of pollination syndromes.

Scope

The aims of this article are (1) to explore the notion of convergence and other concepts (analogy, homoplasy and parallelism) within the theory and practice of developmental evolution and phylogenetic systematics; (2) to modify the definitions of syndromes in order to embrace the concepts of analogy and convergence; (3) to revisit the bat pollination syndrome in the context of angiosperm phylogeny, with focus on the showy ‘petaloid’ organs associated with the syndrome; (4) to revisit the genetic-developmental basis of flower colour; (5) to raise evolutionary hypotheses of floral evolution associated with the bat pollination syndrome; and (6) to highlight some of the current frontiers of research on the origin and evolution of flowers and its impact on pollination syndrome studies in the 21st century.

Conclusions

The inclusion of the concepts of analogy and convergence within the concept of syndromes will constitute a new agenda of inquiry that integrates floral biology, phylogenetic systematics and developmental biology. Phyllostomid and pteropodid bat pollination syndrome traits in eudicots and monocots represent cases of analogous and convergent evolution. Pollination syndromes are a multivariate concept intrinsically related to the understanding of flower organogenesis and evolution. The formulation of hypotheses of pollination syndromes must consider the phylogenetic levels of universality for both plant and animal taxa, flower development, genetics, homology and evolution, and a clear definition of evolutionary concepts, including analogy, convergence, homoplasy and parallelism.
An improved rhythmicity analysis method using Gaussian Processes detects cell-density dependent circadian oscillations in stem cells
Authors: Sahay Shabnam , Adhikari Shishir , Hormoz Sahand , Chakrabarti Shaon
Published: September 2023

Motivation

Detecting oscillations in time series remains a challenging problem even after decades of research. In chronobiology, rhythms (for instance in gene expression, eclosion, egg-laying, and feeding) tend to be low amplitude, display large variations amongst replicates, and often exhibit varying peak-to-peak distances (non-stationarity). Most currently available rhythm detection methods are not specifically designed to handle such datasets, and are also limited by their use of P-values in detecting oscillations.

Results

We introduce a new method, ODeGP (Oscillation Detection using Gaussian Processes), which combines Gaussian Process regression and Bayesian inference to incorporate measurement errors, non-uniformly sampled data, and a recently developed non-stationary kernel to improve detection of oscillations. By using Bayes factors, ODeGP models both the null (non-rhythmic) and the alternative (rhythmic) hypotheses, thus providing an advantage over P-values. Using synthetic datasets, we first demonstrate that ODeGP almost always outperforms eight commonly used methods in detecting stationary as well as non-stationary symmetric oscillations. Next, by analyzing existing qPCR datasets, we demonstrate that our method is more sensitive compared to the existing methods at detecting weak and noisy oscillations. Finally, we generate new qPCR data on mouse embryonic stem cells. Surprisingly, we discover using ODeGP that increasing cell-density results in rapid generation of oscillations in the Bmal1 gene, thus highlighting our method’s ability to discover unexpected and new patterns. In its current implementation, ODeGP is meant only for analyzing single or a few time-trajectories, not genome-wide datasets.

Availability and implementation

ODeGP is available at https://github.com/Shaonlab/ODeGP.
Global differences in tobacco use: who is using what?
Authors: Medianfar Cecilia E , Jemec Gregor B E
Published: September 2023

Hidradenitis suppurativa has been associated with tobacco use, but often only smoking status is recorded. In order to further our understanding on this association, local and cultural differences in tobacco use must be considered in future research.