Article
Physics, Multidisciplinary
Timothy Cohen, Nathaniel Craig, Xiaochuan Lu, Dave Sutherland
Summary: Scattering amplitudes in quantum field theory are geometrically invariant under field redefinitions and can be expressed in terms of Riemannian curvature tensors. A generalized geometric framework is presented to extend the manifest covariance of amplitudes to all allowed field redefinitions. The amplitudes exhibit a recursive relation that resembles the application of covariant derivatives, indicating a notion of on-shell covariance at tree-level.
PHYSICAL REVIEW LETTERS
(2023)
Article
Astronomy & Astrophysics
Daniel Kapec, Y. T. Albert Law, Sruthi A. Narayanan
Summary: This study demonstrates the same identification between gravity and quantum field theory as expectations derived from the celestial conformal field theory formalism for gravity in asymptotically flat spacetimes. The soft limits of moduli scalars in the sigma model are universal and relate to the parallel transport of S-matrix observables over the moduli space of bulk vacua. The leading soft moduli operator corresponds to a marginal deformation in the conformal field theory and coherent states of the soft scalars correspond to finite deformations along the conformal manifold.
Article
Engineering, Civil
Jiang Ding, Zhi Xing, Ziyang Zeng, Weihang Nong, Fei Wu
Summary: In this paper, an LS function based on conformal geometry theory (LSF-CGT) is proposed for topology optimization of shell structures with complex Gaussian curvature. Experimental results demonstrate that LSF-CGT can effectively reduce the strain energy of shell structures with arbitrary Gaussian curvatures, and it can stably and quickly converge to the optimal structure.
Article
Mathematics, Applied
Olimjon Eshkobilov, Emilio Musso, Lorenzo Nicolodi
Summary: This paper focuses on the geometry of critical points of the simplest conformally invariant variational problem for timelike curves in the n-dimensional Einstein universe. It shows that the trajectory of a conformal timelike geodesic is constrained into some totally umbilical Einstein universe of dimension 2, 3, or 4. The paper also discusses the case of conformal timelike geodesics in the 4-dimensional Einstein universe and provides explicit expressions in terms of elliptic functions and integrals.
JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS
(2021)
Article
Mathematics, Applied
Flavio Almeida Lemos, Ezequiel Barbosa
Summary: In this paper, we investigate the properties of the CR Yamabe Operator and CR Yamabe Invariants on compact, connected, strictly pseudo-convex CR manifolds. We provide an upper bound for the Second CR Yamabe Invariant when the First CR Yamabe Invariant is negative, and prove the existence of a minimizer for the Second CR Yamabe Invariant under certain conditions.
COMMUNICATIONS IN CONTEMPORARY MATHEMATICS
(2022)
Article
Computer Science, Software Engineering
Mark Gillespie, Boris Springborn, Keenan Crane
Summary: This paper introduces a numerical method for surface parameterization that produces locally injective and discretely conformal maps on any manifold triangle mesh. The method is extremely robust in practice and provides high-quality interpolation even on meshes with poor elements.
ACM TRANSACTIONS ON GRAPHICS
(2021)
Article
Energy & Fuels
Vahid Safari, Babak Kamkari, Hossein Abolghasemi
Summary: In this research, the combined effects of the shell geometry and downward eccentricity of the heat transfer tube on the melting behavior of the paraffin wax in shell and tube heat exchangers were investigated. The results showed that increasing the eccentricity of the tube accelerated the melting rate, but there was an optimum eccentricity factor for each geometry beyond which the melting rate reduced. It was also found that increasing the eccentricity factor prolonged the convection-dominated melting time and shortened the conduction-dominated melting time.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Mathematics
Sun-Yung Alice Chang, Eden Prywes, Paul Yang
Summary: We study integral curvature conditions for a Riemannian metric on a four-dimensional sphere that quantify the best bilipschitz constant between different metrics. Our results show that the best bilipschitz constant is controlled by specific conditions on the curvature norms. The proof is achieved in two steps by constructing a quasiconformal map between metrics and applying the Ricci flow to establish bilipschitz equivalence.
ADVANCES IN MATHEMATICS
(2022)
Article
Astronomy & Astrophysics
M. R. Setare, A. Jalali
Summary: This study investigates the non-trivial coordinate transformations and their effects on the horizon of Kerr-Bolt black holes using the covariant phase space formalism. The results provide a holographic description of Kerr-Bolt black holes in terms of warped conformal field theory.
Article
Mechanics
Zhilong Peng, Weijun Feng, Jiawei Huang, Peiran Li, Shaohua Chen
Summary: The suture in a turtle shell is an important structural feature that affects both the physiology and mechanical performance of the shell. This study characterizes the morphologies and constructing features of the turtle shell suture and elucidates its effect on the mechanical behaviors of the shell in wet and dry conditions. The suture exhibits hierarchical microstructures and is constructed by interdigitating pyramid-like bony teeth. The presence of the suture endows the turtle shell with flexibility, toughness, and larger deformation. The fracture modes of wet and dry samples differ, with wet samples failing along the suture and dry samples failing along the suture with bony tooth fracturing. The findings deepen the understanding of the hierarchical microstructures of turtle shell and have implications for bio-inspired protective structure design.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Astronomy & Astrophysics
Kristina Giesel, Bao-Fei Li, Parampreet Singh
Summary: The study investigates the consequences of loop quantization on the outermost dust shell in the Lemaitre-Tolman-Bondi spacetime. Different quantization strategies are compared, showing that while both resolve the central singularity, they result in different mass gaps. The presence of gauge-covariant flux modifications can lead to asymmetric evolution of the dust shell and the non-formation of black hole-white hole twins.
Article
Physics, Multidisciplinary
Didier Kileba Matondo, Sunil D. Maharaj
Summary: In this study, a model of a charged anisotropic compact star was investigated by assuming a relationship between metric functions derived from conformal symmetry. This led to a first-order differential equation involving pressure anisotropy and the electric field. By using specific forms of electric field intensity and the Tolman VII metric, new exact solutions expressed in elementary functions were obtained. The model was shown to satisfy causality, stability, and energy conditions for specific parameter values, with numerical values consistent with compact objects such as PSR J1614-2230 and SMC X-1.
Article
Engineering, Multidisciplinary
Xiaoqiang Xu, Xianfeng David Gu, Shikui Chen
Summary: This paper presents a dimension reduction level set method (DR-LSM) based on conformal geometry theory for shape and topology optimization of heat conduction problems on free-form surfaces. The method is capable of transforming the original 3D problem into a 2D parameter domain, reducing computational cost and overcoming challenges of dynamic boundary evolution. Numerical examples demonstrate the effectiveness and efficiency of the proposed method.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Biodiversity Conservation
Adan Perez-Garcia
Summary: A new pleurodiran turtle, identified as attributable to Bothremydidae, is described from an Upper Cretaceous outcrop in Southwestern Niger. The unique features of Abalakemys chapmanae gen. et sp. nov. include an almost complete large shell, an exclusive ornamental pattern on the plate's outer surface, small fourth pleural scutes, and a noticeably wedged posterior plastral lobe. This turtle could belong to Nigeremydini, a poorly understood lineage of Bothremydodda that inhabited the African Trans-Saharan seaway, with limited shell information available.
Article
Mathematics
Giada Franz, Federico Trinca
Summary: In this paper, we investigate an n-dimensional Riemannian sphere that is conformal to the round one and has 8-pinched curvature. We prove that this sphere does not contain any closed stable minimal submanifold of dimension 2=k=n-d(-1).
JOURNAL OF GEOMETRIC ANALYSIS
(2023)
Article
Multidisciplinary Sciences
Prabhakaran Vasantha-Srinivasan, Pavana K. Sivadasan Unni, Sengodan Karthi, Raja Ganesan, Sengottayan Senthil-Nathan, Muthiah Chellappandian, Narayanaswamy Radhakrishnan, Rajakrishnan Rajagopal, Krutmuang Patcharin
Summary: This study investigates the phyto-chemical screening and toxicity of chloroform crude extracts from Ageratum conyzoides on the pest Spodoptera litura and beneficial earthworm. The results show that the extract is toxic to the pest and has adverse effects on larval-pupal growth and development. However, it is less toxic to non-target earthworms.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
Govindan Rajivgandhi, Chenthis Kanisha Chelliah, Manavalan Murugan, Govindan Ramachandran, Gnanasekaran Chackaravarthi, Muthuchamy Maruthupandy, Franck Quero, Arulraj Arunachalam, Mangalaraja Ramalinga Viswanathan, Jamal M. Khaled, Fetim S. AlHarbi, Wen-Jun Li
Summary: This study focuses on the screening and analysis of phytochemical and bioactive compounds from the marine mangrove plant Avicennia marina. The results confirm the antioxidant, antimicrobial, and bactericidal activities of the plant extract. The findings suggest that A. marina has the potential to be a future drug discovery plant against multidrug resistant pathogens.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
Mohd Javed Akhtar, Maqusood Ahamed, Hisham Alhadlaq
Summary: This study compares the effects of two types of cobalt-based nanoparticles on lung cells and finds that cobalt nanoparticles are more toxic to cells than cobalt-iron oxide nanoparticles, possibly due to the higher release of Co2+ ions by cobalt nanoparticles. Additionally, the study suggests that CalceinAM alone is insufficient to assess the toxicity of cobalt-based nanoparticles, and other methods should be used for further confirmation.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
Ahmad Mohammad Salamatullah, Mohammed Asif Ahmed, Khizar Hayat, Fohad Mabood Husain, Shaista Arzoo, Abdulhakeem Alzahrani, Asdaf Alotaibi, Heba Khalil Alyahya, Syed Rizwan Ahmad
Summary: This study investigated the effects of different drying methods on the polyphenol and flavonoid content, as well as the antioxidant properties of rose petals. The results showed that oven-dried samples had the highest levels of polyphenols and flavonoids, as well as the strongest antioxidant activity.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
J. Bharathi, S. Nandhini
Summary: This paper considers a single-server queue model with Modified Bernoulli Vacation. The server offers Compulsory Service and Non-Compulsory Re-service. The Probability Generating Function for the system is derived using the Supplementary Variable Method, and numerical examples are discussed to demonstrate the impact of system parameters.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
Raju Suresh Kumar, Dhaifallah M. Al-thamili, Khloud Ibrahim Al-Shemaimari, Faruq Mohammad, Mohamad Altaf, Rashid Ayub
Summary: Eight new functionalized spirooxindole-pyrrolizidine heterocyclic hybrids have been synthesized and characterized. The compound with no substitution on the aryl rings displayed the highest anticancer activity. The most active compounds were further tested for toxicity effects and their impact on cell viability was investigated by assaying free radicals, apoptosis, and caspases.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
Alaa Ali Hameed
Summary: This study provides a comprehensive analysis of the integration of hyperspectral sensors and artificial intelligence. It proposes a hybrid strategy that combines BPVAM with PCA for the classification of hyperspectral images and demonstrates that this model is efficient for hyperspectral sensor classification.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
Muhammad Muzaffar Ali Khan Khattak, Nor Azwani Mohd-Shukri, Tahir Mahmood, Mukhtar Ahmed, Syed Najmul Hejaz Azmi, Mahboob Alam, Murni Nazira Sarian, Qamar Uddin Ahmed
Summary: This research aimed to evaluate the effect of mixed herbs on blood HbA1c and liver function in type 2 diabetes mellitus patients. The results showed that the consumption of mixed herbs improved HbA1c levels without significant changes in blood urea, creatinine, and liver enzymes.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
Natarajan Arumugam, Khloud Ibrahim Al-Shemaimari, Mohammad Altaf, Karuppiah Ponmurugan, Dhanaraj Premnath, Sinouvassane Djearamane, Ling Shing Wong, Saminathan Kayarohanam
Summary: This study synthesized a new class of spiro compounds as potential antibiotics and evaluated their antimicrobial efficacy. Compound 4a showed significant activity against tested pathogens. This research is important for the development of effective antimicrobial therapies.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
Zsolt Giczi, Beatrix Sik, Viktoria Kapcsandi, Erika Lakatos, Angela Mrazik, Rita Szekelyhidi
Summary: This study examined the composition of micro- and macroelements, total antioxidant, and polyphenols in different types of dried houseleek and fresh plant decoctions. The results showed that the type of houseleek greatly influenced the composition. Mn was present in high amounts among microelements, while Ca and Na were present in larger quantities among macroelements. The drying methods had some influence on the antioxidant and polyphenol content.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
Eunjeong Jeon, Sangbuem Cho, Seongsoo Hwang, Kwanghyun Cho, Cedric Gondro, Nag-Jin Choi
Summary: A body weight prediction model was developed using milk production traits, providing a useful indicator for energy balance evaluation in dairy cows. The deep neural network (DNN) model showed the best predictive accuracy for body weight compared to other models. It was found that the transition from negative to positive energy balance varied among cows. Energy balance indexes were proposed to estimate and monitor individual cows' energy balance during lactation.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
Sohail Rehman, Souhail Bouzgarrou, Mehdi Akermi, Hashim
Summary: This study investigates the steady flow of viscoelastic fluid in a deformable channel. The mathematical structure for computing the impacts of fluid viscoelasticity on the flow is provided, and the dimensionless variables influencing the interaction between the fluid and structure are identified. The results show that the converging and diverging sections of the channel are affected similarly by the inertial forces and channel opening. Longer strain delaying time and shorter stress relaxation phase improve the velocity profile of the fluid flow.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Article
Multidisciplinary Sciences
Muhammad Umar Ijaz, Syeda Sania Zahara, Moazama Batool, Mikhlid H. Almutairi, Ayesha Ishtiaq, Asma Ashraf
Summary: This experiment evaluated the therapeutic effects of Kaempferide (KMF) on Paraquat (PQ) induced cardiac toxicity in rats. The findings showed that KMF alleviated the cardiac damage caused by PQ through reducing oxidative stress and inflammation.
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)
Correction
Multidisciplinary Sciences
Saganuwan Alhaji Saganuwan, Otiger Fredrick Egworrow, Agbo Joseph Ode
JOURNAL OF KING SAUD UNIVERSITY SCIENCE
(2024)