bluuebunny/crossref_metadata_2025_split huggingface dataset:
Primordial black holes and stochastic inflation beyond slow roll. Part I. Noise matrix elements
Authors: Mishra Swagat S. , Copeland Edmund J. , Green Anne M. 
Published: September 2023

AbstractPrimordial Black Holes (PBHs) may form in the early Universe, from the gravitational collapse of large density perturbations, generated by large quantum fluctuations during inflation. Since PBHs form from rare over-densities, their abundance is sensitive to the tail of the primordial probability distribution function (PDF) of the perturbations. It is therefore important to calculate the full PDF of the perturbations, which can be done non-perturbatively using the `stochastic inflation' framework. In single field inflation models generating large enough perturbations to produce an interesting abundance of PBHs requires violation of slow roll. It is therefore necessary to extend the stochastic inflation formalism beyond slow roll. A crucial ingredient for this are the stochastic noise matrix elements of the inflaton potential. We carry out analytical and numerical calculations of these matrix elements for a potential with a feature which violates slow roll and produces large, potentially PBH generating, perturbations. We find that the transition to an ultra slow-roll phase results in the momentum induced noise terms becoming larger than the field noise whilst each of them falls exponentially for a few e-folds. The noise terms then start rising with their original order restored, before approaching constant values which depend on the nature of the slow roll parameters in the post transition epoch. This will significantly impact the quantum diffusion of the coarse-grained inflaton field, and hence the PDF of the perturbations and the PBH mass fraction.
Testing BSM physics with gravitational waves
Authors: Muia F. , Quevedo F. , Schachner A. , Villa G. 
Published: September 2023

Abstract
The Cosmic Gravitational Wave Background (CGWB) is an irreducible background of gravitational waves generated by particle exchange in the early Universe plasma. Standard Model particles contribute to such a stochastic background with a peak at f∼80 GHz. Any physics beyond the Standard Model (BSM) may modify the CGWB spectrum, making it a potential testing ground for BSM physics.
We consider the impact of general BSM scenarios on the CGWB, including an arbitrary number of hidden sectors.
We find that the largest amplitude of the CGWB comes from the sector that dominates the energy density after reheating and confirm the dominance of the SM for standard cosmological histories.
For non-standard cosmological histories, such as those with a stiff equation of state ω > 1/3, like in kination, BSM physics may dominate and modify the spectrum substantially.
We conclude that, if the CGWB is detected at lower frequencies and amplitudes compared to that of the SM, it will hint at extra massive degrees of freedom or hidden sectors.
If it is instead measured at higher values, it will imply a period with ω > 1/3.
We argue that for scenarios with periods of kination in the early Universe, a significant fraction of the parameter space can be ruled out from dark radiation bounds at BBN.
Why is zero spatial curvature special?
Authors: Jimenez Raul , Khalifeh Ali Rida , Litim Daniel F. , Matarrese Sabino , Wandelt Benjamin D. 
Published: September 2023

Abstract
Evidence for almost spatial flatness of the Universe has been provided from several observational probes, including the Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAO) from galaxy clustering data. However, other than inflation, and in this case only in the limit of infinite time, there is no strong a priori motivation for a spatially flat Universe. Using the renormalization group (RG) technique in curved spacetime, we present in this work a theoretical motivation for spatial flatness. Starting from a general spacetime, the first step of the RG, coarse-graining, gives a Friedmann-Lemaître-Robertson-Walker (FLRW) metric with a set of parameters. Then, we study the rescaling properties of the curvature parameter, and find that zero spatial curvature of the FLRW metric is singled out as the unique scale-free, non-singular background for cosmological perturbations.
Production rates of dark photons and Z' in the Sun and
stellar cooling bounds
Authors: Li Shao-Ping , Xu Xun-Jie 
Published: September 2023

Abstract
Light weakly interacting particles could be copiously
produced in the Sun which, as a well-understood star, could provide
severe constraints on such new physics. In this work, we calculate
the solar production rates of light gauge bosons (e.g. dark photon)
arising from various U(1) extensions of the standard model. It
is known that the dark photon production rate is suppressed by the
dark photon mass if it is well below the plasmon mass of the medium.
We show that for more general U(1) gauge bosons, this suppression
is absent if the couplings are not in alignment with those of the
photon. We investigate a few frequently discussed U(1) models including
B - L, Lμ - Lτ
, and Le - Lμ(τ)
, and derive
the stellar cooling bounds for these models.
Direct Ion Beam Figuring Process and Rotational Measurement Method for Ultra-smooth Aspherical Surfaces of a 46.5 nm Telescope
Authors: Gu Weichen , Yu Jun , Sheng Pengfeng , Wu Qiaoyu , Huang Qiushi , Wang Zhanshan 
Published: September 2023

Abstract
This paper describes a fabrication process for the hyperboloidal concave mirror of a 46.5 nm telescope. The 180 mm aperture hyperboloidal concave mirror and 70 mm aperture compensator are machined directly from chemical mechanical polishing of a spherical surface to a high-accuracy aspherical surface by ion beam figuring. The aspherical measurement method is the Dall null test. To minimize system errors in the measurement process, the rotational measurement method with six rotations is used in the null test. The results of the analysis for the ME (first solve the machined surface profile, then solve the system errors) and EM (first solve the system errors, then solve the machined surface profile) methods of calculation in the measurement are given. The ME method is a more accurate rotational test method, and the six rotations are appropriate for rotational measurements. After the figuring process, the hyperboloidal concave mirror surface profile reached 8.27 nm rms and the compensator surface profile is approximately 4 nm rms. The roughness of the hyperboloidal concave mirror is smooth to 0.160 nm rms.
Numerical analysis of graphene oxide modified glass fiber/epoxy resin composites
Authors: Ni Xuweilai , Zhu Chenyang , Chen Long 
Published: September 2023

Abstract
Graphene is extensively used as a functional material due to its superb heat transfer and electrical conductivity properties. In this paper, sample graphene oxide /glass fiber/epoxy resin composites were prepared by ultrasonic decentralization. The heat transfer and stress distribution of the graphene-doped fiber-reinforced resin matrix composites were simulated by mathematical modelling. The reliability of the numerical heat transfer model is illustrated by comparing the measured temperature field distribution of the graphene oxide/glass fiber/epoxy composite samples with the numerical simulation results. It is also shown that graphene particles can facilitate heat transfer and the epoxy resin in the composite expands significantly more than the fibers, so the compressive stress on the fibers at the interface strengthens the bond between resin and fibers. Still, the thermal stress can cause the glass fiber ends to detach from the resin material and affect the material life.
Study on heat transfer failure time effect energy of lithium heat pipe
Authors: Zhang Yitong , Zhou Tao , Liu Wenbin , Wei Dong , Mao Shang , Xue Chunhui , Lu Huaichang , Yao Yao 
Published: September 2023

Abstract
Studying the efficiency of lithium heat pipe above 1000K in case of problems is of considerable value for mastering and controlling its safety. We use COMSOL software to model and calculate a single element above 1000 K, and calculate and analyze its various parameter changes under fault conditions. According to different situations that should be classified and discussed, the cold end fluid temperature and corresponding heat transfer coefficient in the lower temperature area, as well as the temperature situation at the other end, should be separately considered. Based on the calculated results, it is discussed that they all undergo linear and proportional changes with the target parameters, and the fluid situation on the lower temperature side has the smallest impact on these target results. The maximum temperature of the module will reach 1900K, and materials that can withstand 1900K need to be selected during design.
Cu2GeS3/Cd0.5Zn0.5S Heterojunction Thin Film Solar Cells
Authors: Bao Wujisiguleng , Qiu Fangyuan , Bai Sachuronggui 
Published: September 2023

AbstractTernary compounds such as Cu2GeS3(CGS) and Cu2SnS3(CTS) semiconductor materials have been considered as lower defects and environmentally friendly absorber layer materials for solar cells. In this work, the band offsets for CGS/CdS and CTS/CdS heterointerface are calculated by the first-principles calculation method. The valence band maximum (VBM) of CdS is below CGS (valence band offset ΔEV=1.4 eV), and the conduction band minimum (CBM) of CdS is below CGS (conduction band offset ΔEC=0.5 eV), i.e., the CGS/CdS is type II interface. The VBM of CdS is below CGS (ΔEV=1.4 eV), and the CBM of CdS is above CTS(ΔEC=-0.1 eV), i.e., the CTS/CdS heterojunction is type I. We also obtained the type I of CGS/Cd1−xZnxS heterointerface with a favorable barrier height of 0.2 eV by adjusting the composition of x in Cd1−xZnxS alloy with 0.5.
A Study on the Influencing Factors of the Compressive Strength of Planting Concrete
Authors: Liu Ying , Liu Dehua , Ma Lijie 
Published: September 2023

Abstract
It is a study on the influence of aggregate size, water-cement ratio, and target porosity on the compressive strength of planting porous concrete. Experiment results show that porous concrete’s compressive strength is negatively correlated with target porosity and aggregate size; no distinct linear relation with the water-cement ratio is indicated, and there is an optimal water-cement ratio in different mix proportions. Among the three factors influencing the compressive strength of porous concrete, target porosity ranks first in influence and is followed successively by aggregate size and water-cement ratio. Besides, the paste-coating method is helpful in the formation of connected pores of porous concrete.
Investigation on Rheological Characterization of Isotropic Conductive Adhesives
Authors: Li Saipeng , Jiang Qinglei , Wang Xuyan 
Published: September 2023

Abstract
In the field of microelectronic packaging technology, isotropic conductive adhesives (ICAs) have been used widely as interconnection materials between chips and substrates. ICAs are composed of silver powder particles and adhesive matrix. The paper analysed the rheological properties of ICAs at different temperatures in order to better apply ICAs in dispensing and jet printing processes. The viscosity, viscoelasticity, and thixotropic behaviours of ICAs were studied using various experimental methods such as oscillatory stress shear, and rotational rheology. The rheological behaviours of ICAs conforms to the Cross Model. In SAOS flow field, the ICAs has G”>G’ in LVR region, which shows the viscous component is dominant and ICAs represent viscoelastic fluid characteristics.
Influence of ultrasonic impact treatment on corrosion resistance of 7075 aluminum alloy welded joint
Authors: Ding BoSheng , He MingTao , Ma RongBin , Xie Li , Wang JiangTao , Zou ShengGuang , Liu Chang 
Published: September 2023

Abstract
To enhance the resist corrosion and service safety of 7075 aluminum alloy FSWed joints, an ultrasonic impact treatment was applied, and its effects on the surface morphology, microhardness, residual stress, and corrosion performance of the welded joint were investigated. The experimental results showed that after impact, the surface of the welded joint exhibited larger undulations. The distribution trend of micro-hardness changed from a “W” distribution to a uniform distribution, and the tensile residual stress (TRS) on the surface of the welded joint transformed into compressive residual stress (CRS). After the ultrasonic impact treatment, only minimal pitting corrosion occurred on the welded joint, and the corrosion current density decreased, while the capacitance arc radius increased. The resist corrosion of the welded joints was ameliorated.
Synthesis and Characterization of a New In-based Metal Organic Framework
Authors: Feng Mengchu , Yu Xinyu 
Published: September 2023

Abstract
In this work, by meticulously selecting high-valence intermetallic ions and functional tetracarboxylic acid organic ligands, we had the opportunity to effectively develop a new metal-organic framework In-MOFs. Metal nodes in In-MOF are interestingly linked to organic ligands, and twisted decahedra behave as tetrahedra, producing a 3D
pts
topology. These structures have been investigated via SCXRD, PXRD, and Fourier transform infrared (FT-IR). In-MOF features two one-dimensional channels of varying diameters in the c-axis and b-axis directions, 17.4 Å × 4.2 Å and 17.3 Å× 7.5 Å, respectively, and possesses high solvent stability.
Study of the Effect of double slotted construction on motor slot torque
Authors: Yan Hongliang , Wu Yabin 
Published: September 2023

Abstract
To address the problem of vibration and noise caused by high slot torque of stacked-in permanent magnet synchronous motor, a motor model with a rectangular slot in the stator and curved slot in the rotor is proposed to analyze the variation of slot torque with the auxiliary slot parameter based on the analysis of slot torque, taking an 8-pole 36-slot built-in permanent magnet synchronous motor as an example. The modeling results display that the slot torque reduces and then increases with the change of incomplete groove parameters. The slot torque is weakened by 92.01% when the stator with a rectangular slot rotor with a curved slot.
Design and Fabrication of an Environment Simulation Test Bed for Deep-sea Laser Cladding
Authors: Zhang Yingying , Liu Jingxi , Dong Wenkui 
Published: September 2023

Abstract
The complicated deep-sea high-pressure environment poses a significant challenge for deep-sea laser cladding. To solve this problem, an environment simulation test bed for deep-sea laser cladding is developed in this paper. First, a principle of environment simulation testbed is proposed, which can provide high-pressure water for underwater laser cladding simulation experiments. Based on the principle design, the structure of the environment simulation test bed is modeled in three dimensions, which can carry out underwater laser cladding experiments. Then, the strength of the pressure chamber is analyzed by finite element simulation. Finally, the environment simulation test bed for deep-sea laser cladding is modularly manufactured and integrally packaged. The environment simulation test bed for deep-sea laser cladding can be directly applicable to simulate underwater laser cladding.
Improving Neutron-gamma discrimination in CLYC with Gaussian mixture model
Authors: Chen Jiaolong , Guo Jianhua , Wang Shen , Wan Qiang , Xu Xing , Chen Yiren , Cui Yuxin , Zhang Yan , Zhang Yongqiang 
Published: September 2023

Abstract
Neutron and gamma discrimination is a common issue in neutron detection. Cs
2
LiYCl
6:Ce (CLYC) crystal, with its unique core-to-valence luminescence (CVL) mechanism for gamma rays, has excellent capability for neutron-gamma discrimination. This paper proposes a new preprocessing method called constant fraction alignment (CFA), based on the fast rise and slow decay characteristics of CLYC, to effectively improve discrimination performance. Unsupervised classification methods that do not require training data have a great advantage since pure neutron sources are difficult to obtain. As an unsupervised clustering method, Gaussian mixture model (GMM) is used to achieve neutron-gamma discrimination of data detected by CLYC, and the impact of different parameters on GMM results is studied. When the input dimension is high, GMM not only requires significantly more time but also reduces precision, so dimensionality reduction is necessary. Principal component analysis (PCA) is a commonly used dimensionality reduction method, and through analysis, it is found that using the first three components of PCA as inputs achieves the best performance. In the GMM solving process, selecting different covariance matrices based on data types can reduce running time while maintaining high accuracy. Diagonal mode is the most suitable according to comparison. Based on the same dataset, the accuracy of GMM is higher than that of charge comparison method and k-means++, with an accuracy of 99.96% for 252
Cf source and a false alarm rate as low as 0.01% for 137
Cs source.
Wet-bulb temperatures reveal inequitable heat risk following climate change in Hong Kong
Authors: Boyle Michael J W 
Published: September 2023

Abstract
Rising temperatures will impact urban communities, which are growing as a proportion of the global population. However, the effects of increasing temperature may not be felt equally, with less wealthy neighbourhoods experiencing hotter thermal environments in some urban areas because of geographic location and tree cover. While relationships have been drawn between wealth inequality and temperature in urban areas, these rarely project into the future or combine humidity and air temperatures into ‘wet-bulb temperature’ at fine spatial resolution, which is more directly relevant to the human experienced environment. Here I present an analysis of present and future wet-bulb temperatures in Hong Kong, an economically developed subtropical city in South-East Asia. I couple census data with recently available 30 × 30 m resolution climate models to examine how the income of districts and their physical characteristics are correlated with human-experienced local temperatures. I uncover evidence of thermal inequity, with wealthier districts exhibiting cooler conditions than less wealthy districts. Projecting into the future using three different climate change scenarios I demonstrate that wet-bulb temperatures considered dangerous to human survival may be commonly experienced in Hong Kong by the end of the century. However, the wealthiest districts of Hong Kong are likely to have a thermal safety margin of at least 25–30 years more than the least wealthy districts before these dangerous temperatures are reached. Due to the high population density and economic importance of the region, these findings have significant implications for public health and urban planning as global temperatures continue to rise.
Multimodal fluorescence imaging and spectroscopic techniques for oral cancer screening: a real-time approach
Authors: Thapa Pramila , Singh Veena , Bhatt Sunil , Maurya Kiran , Kumar Virendra , Nayyar Vivek , Jot Kiran , Mishra Deepika , Shrivastava Anurag , Mehta Dalip Singh 
Published: September 2023

Abstract
The survival rate of oral squamous cell carcinoma (OSCC) patients is very poor, but it can be improved using highly sensitive, specific, and accurate techniques. Autofluorescence and fluorescence techniques are very sensitive and helpful in cancer screening; being directly linked with the molecular levels of human tissue, they can be used as a quantitative tool for cancer detection. Here, we report the development of multi-modal autofluorescence and fluorescence imaging and spectroscopic (MAF-IS) smartphone-based systems for fast and real-time oral cancer screening. MAF-IS system is indigenously developed and offers the advantages of being a low-cost, handy, non-contact, non-invasive, and easily operable device that can be employed in hospitals, including low-resource settings. In this study, we report the results of 43 individuals with 28 OSCC and 15 oral potentially malignant disorders (OPMDs), i.e., epithelial dysplasia and oral submucous fibrosis, using the developed devices. We observed a red shift in fluorescence emission spectra in vivo. We found red-shift of 7.72 ± 6 nm, 3 ± 4.36 nm, and 1.33 ± 0.47 nm in the case of OSCC, epithelial dysplasia, and oral submucous fibrosis, respectively, compared to normal. The results were compared with histopathology and found to be consistent. Further, the MAF-IS system provides results in real-time with higher accuracy and sensitivity compared to devices using a single modality. Our system can achieve an accuracy of 97% with sensitivity and specificity of 100% and 94.7%, respectively, even with a smaller number of patients (28 patients of OSCC). The proposed MAF-IS device has great potential for fast screening and diagnosis of oral cancer in the future.
The effects of varying wall thickness on the surface roughness of Ti-6Al-4V by electron beam powder bed fusion
Authors: Carolo Lucas C B , Cooper O Robert E , de Oliveira Marcelo F , da Silva Jorge V L 
Published: September 2023

Abstract
While the electron beam powder bed fusion (EB-PBF) process is recognized for generating parts with high surface roughness, the impact of wall thickness remains relatively understudied and shows inconsistent literature results. This study addresses this gap by performing a full factorial Design of Experiments (DoE) to examine Ti-6Al-4V specimen surfaces built in three distinct orientations (vertical, upskin, and downskin) and six wall thickness levels (0.5, 1.0, 2.0, 2.5, 3.0, and 4.0 mm). Findings reveal orientation-dependent effects of wall thickness on surface roughness, particularly for thicknesses below 1.0 mm. Vertical surfaces show increased roughness with decreasing wall thickness, in which 0.5 mm-thick specimens exhibited the highest Ra roughness values. In contrast, no particular trend was observed for upskin surfaces, with 0.5 mm specimens displaying roughness values comparable to the 2.0 to 4.0 mm range of specimens. Yet, downskin surfaces of 0.5 mm specimens showed significantly lower Ra roughness compared to their thicker counterparts, a trend opposite of that of vertical surfaces. These behaviors may relate to scanning strategies and electron beam parameters, particularly when building smaller cross-sectional areas.
Study on strength, durable and flexural behaviour of partial replacement of sugarcane bagasse ash over cement
Authors: Lourdu Arun Raja , Ali Shahul Hameed Masthan 
Published: September 2023

Abstract
Tonnes of cement are produced and used due to boom in infrastructure sector. During the process of production of cement, lot of CO2 has been emitted. It is estimated around 4%–8% of CO2 has been emitted from cement production. There is high need for address this issue. Because of its renewable nature and high silica content, Agriculture waste ash is gaining popularity as a viable alternative to traditional cementitious materials. It has been found by (Hernandez et al
1998) that Sugarcane bagasse ash shows good pozzolanic activity. Sugarcane bagasse ash (SCBA) is a waste-free renewable energy source made from sugarcane fibres. Many attempts have been made to study the SCBA as partial replacement for cement. The same has been checked in this study with extension for structural members have been done. The results of tests on concrete and concrete containing a partial replacement of cement made from sugarcane bagasse ash (SCBA) are the most important details in this text. The substitution of 10% SCBA resulted in the greatest increase in compressive strength, followed by a modest increase in split tensile strength maximum strength. The study findings allow for the conclusion that the Concrete that was built has high durability qualities. The flexural behaviour also showed very good performance. The use of Bagasse Ash shows improved performance due to is micro grain size and crystallographic nature. The replacement of 10% SCBA results in overall better performance.