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Arctic sea-ice extent: No record minimum in 2023 or recent years

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Atmospheric and Oceanic Science Letters 2025年第1期18卷 52-55页

作者： Ola m.Johannessen Tor i.Olaussen Nansen Scientific Society BergenNorway Nansen Environmental and Remote Sensing Center BergenNorway

Arctic sea-ice extent reaches its minimum each year in September. On 11 September 2023 the minimum was 4.969 million square kilometers(***^(2)). This was not a record low, which occurred in 2012, when the minimum was 4.175 ***^(2), 0.794 ***^(2) less than the minimum in 2023. However, the ice extent had decreased by 0.432 ***^(2) compared with 2022. Nevertheless, the summer melting in 2023 was remarkably less than expected when considering the strong heat waves in the atmosphere and ocean, with record temperatures set around the world. in general, there is a high correlation between the long-term decrease in sea-ice extent and the increasing CO_(2) in the atmosphere, where the increase of CO_(2) in recent decades explains about 80% of the decrease in sea ice in September, while the remainder is caused by natural variability.

关键词： Sea ice Arctic minimum ice Climate

The GPBiCG(m, l) method for Solving General matrix Equations

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Journal of mathematical Research with Applications 2019年第4期39卷 408-432页

作者： Basem i.selim Lei DU Bo YU Xuanru ZHU School of mathematical Sciences Dalian University of Technology mathematics and Computer Science Department Faculty of Science Menoufia University

The generalized product bi-conjugate gradient(GPBiCG(m,l))method has been recently proposed as a hybrid variant of the GPBi CG and the Bi CGSTAB methods to solve the linear system Ax=b with non-symmetric coefficient matrix,and its attractive convergence behavior has been authenticated in many numerical *** means of the Kronecker product and the vectorization operator,this paper aims to develop the GPBi CG(m,l)method to solve the general matrix equation■ and the general discrete-time periodic matrix equations■ which include the well-known Lyapunov,Stein,and Sylvester matrix equations that arise in a wide variety of applications in engineering,communications and scientific *** accuracy and efficiency of the extended GPBi CG(m,l)method assessed against some existing iterative methods are illustrated by several numerical experiments.

关键词： GPBiCG(m,l) method Krylov Subspace method matrix equations Kronecker product vectorization operator

An improved Security Scheme for iEC 61850mmS messages in intelligent Substation Communication Networks

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Journal of modern Power Systems and Clean Energy 2020年第3期8卷 591-595页

作者： Taha selim Ustun S.m.Suhail Hussain Fukushima Renewable Energy institute AIST(FREA)FukushimaJapan Research institute of the Energy Frontier TsukubaJapan

Advanced connectivity in substations brings along cybersecurity considerations. Especially, the use of standardized data objects and message structures stipulated by iEC 61850 makes them much more vulnerable to unauthorized access and manipulation. in order to tackle these vulnerabilities, different methods are investigated by researchers all over the world. An important aspect of such efforts is the real-time performance consideration since power systems are bound by the rules of physics and all control/communication tasks need to be completed in a certain time frame. Security schemes for substation communication have been proposed in the recent literature. However, they must be improved to ensure a full security solution. Recently published iEC 62351 standard aims to fill this gap. Node authentication is vital for substation communication networks based on iEC 61850 to mitigate a variety of attacks such as man-in-the-middle(miTm) attack. This short communication presents a node authentication mechanism based on transport layer security(TLS) with certificates to address this knowledge gap. it also investigates the real-time performance by implementing the proposed scheme with Python.

关键词： iEC 62351 standard certificate authority cer-tificate-based authentication cybersecurity smart grid

Torsional Wave in a Dissipative Cylindrical Shell Under initial Stresses

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Computers, materials & Continua 2022年第2期70卷 3021-3030页

作者： mahmoud m.selim Khaled A.Gepreel Department of mathematics-College of Sciences&Humanities in Al Aflaj Prince Sattam bin Abdulaziz UniversityAl-Aflaj11912KSA Department of mathematics Suez Faculty of ScienceSuez UniversityEgypt Department of mathematics Faculty of ScienceTaif UniversityTaif21944Saudi Arabia

The dispersion relation of torsional wave in a dissipative,incompressible cylindrical shell of infinite length incorporating initial stresses effects is *** governing equation and closed form solutions are derived with the aid of Biot’s *** velocity and damping of torsional wave are obtained analytically and the influences of dissipation and initial stresses are studied in *** proposed a new method for obtaining the phase and damping velocities of torsional wave in a complex *** results analyzing the torsional wave propagation incorporating initial stress effects are analyzed and presented in *** analytical and numerical solutions reveal that,the dissipation as well as the initial stresses have notable impacts on the phase velocity of torsional wave in a pre-stressed dissipative cylindrical *** numerical results reveal that,the initial stresses and dissipation,considerably,effect the phase velocity of the torsional *** has been observed that,any change in dissipation parameter(δ)produces a substantial change in damping velocity of torsional *** addition,it can be seen that,the phase velocity increases as the initial stress parameter ***,the result of numerical simulation illustrated the influence of dissipation and initial stresses on damping and phase velocities of torsional wave *** conclusion made shown the consistency with the Biot’s incremental deformation theory,and the effective on model such as engineering mechanics and displacement of particles.

关键词： Propagation torsional wave dissipation cylindrical shell initial stress

inhibitive Effect of Some Aldehydes on Corrosion ofAl-3mg Alloy in Acid Solutions

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Journal of materials Science & Technology 1998年第4期14卷 313-319页

作者： i.Z.selim (Physical Chemistry Dept., National Research Center, Dokki, Cairo, Egypt) Physical Chemistry Dept. National Research Center Dokki Cairo Egypt

2m hydrochloric acid solution was used and the methods of polarization and weight loss measurements were adopted. The two methods give the same order of inhibition efficiency. Polarization studies reveal that catholic polarization is more pronounced than the anodic one. The results indicate that all the studied compounds excellent corrosion inhibitors and the percentage efficiency varying with both the type and concentration of the inhibitor and being in the following order: p-methoxy-benzaldehyde (1)benzaldehyde (2)p-chlorobenzaldehyde (3)p-nitrobenzaldehyde (4). The degree of surface coverage of the adsorbed additives was determined and the results obey the Langmuir isotherm. Effect of temperature on the corrosion rate in absence and presence of different concentrations of the used inhibitors was investigated by using weight loss measurements. The results indicate that the corrosion rate rapidly increases with increasing temperature. (Edited author abstract) 19 Refs.

关键词： Champion benzaldehyde blank Adsorption Singh Pearson Chapman Egypt London

Comprehensive toxicity assessment of nanodiamond on <i>Blaps polychrestai>: implications and novel findings

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iNSECT SCiENCE 2024年第6期31卷 1838-1863页

作者： Saad, marwa selim, Nabila El-Samad, Lamia m. Alexandria Univ Fac Sci Dept Zool Alexandria Egypt Alexandria Univ Fac Sci Dept Zool Baghdad st Qism Moharram Bek Alexandria 21568 Egypt

With the increasing development of nanomaterials, the use of nanodiamonds (NDs) has been broadly manifested in many applications. However, their high penetration into the ecosystem indubitably poses remarkable toxicological risks. This paper investigates the toxic effects of NDs on the darkling beetle, Blaps polychresta Forskal, 1775 (Coleoptera: Tenebrionidae). Survival analysis was carried out by monitoring the beetles for 30 d after the injection of four different doses of NDs. A dose of 10.0 mg NDs/g body weight, causing less than 50% mortality effect, was assigned in the analysis of the different organs of studied beetles, including testis, ovary, and midgut. Structural and ultrastructural analyses were followed using light, TEm, and SEm microscopes. in addition, a variety of stress markers and enzyme activities were assessed using spectrophotometric methods. Furthermore, cell viability and DNA damage were evaluated using cytometry and comet assay, respectively. Compared to the control group, the NDs-treated group was exposed to various abnormalities within all the studied organs as follows. Significant disturbances in enzyme activities were accompanied by an apparent dysregulation in the antioxidant system. The flow cytometry results indicated a substantial decrease of viable cells along with a rise of apoptotic and necrotic cells. The comet assay demonstrated a highly increased level of DNA damage. Likewise, histological analyses accentuated the same findings showing remarkable deformities in the studied organs. Prominently, the research findings substantially contribute for the first time to evaluating the critical effects of NDs on B. polychresta, adopted as the bioindicator in this paper.

关键词： Blaps polychresta ecotoxicity molecular analysis nanodiamond oxidative stress pathophysiology

The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury

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Neural Regeneration Research 2025年第11期20卷 3317-3329页

作者： Jennifer m.Colón-mercado Aranza i.Torrado-Tapias iris K.Salgado Jose m.Santiago Samuel E.Ocasio Rivera Dina P.Bracho-Rincon Luis H.Pagan Rivera Jorge D.miranda Department of Physiology University of Puerto RicoMedical Sciences CampusSan JuanPRUSA National institutes of Health National Human Genome Research InstituteBethesdaMDUSA Universidad Central del Caribe School of MedicineBayamónPRUSA University of Puerto Rico Carolina CampusCarolinaPRUSA institute of Neurobiology San JuanPRUSA

in addition to the loss of motor function,~60% of patients develop pain after spinal cord *** cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic *** can lead to the formation of new connections triggering abnormal sensory *** excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and *** previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator *** this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord *** hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant *** and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical *** treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent *** expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on *** rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased

关键词： allodynia central neuropathic pain EAAT-1/GLAST EAAT-2/GLT-1 glutamate transporters selective estrogen receptor modulator sexual dimorphism spinal cord injury trauma

Dielectric Properties of Some Aldehydes

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Journal of materials Science & Technology 1995年第3期11卷 222-228页

作者： i.m.El-Anwnr and i.Z.selim (Physical Chemistry Dept., National Research Centre, Dokki, Cairo, Egypt)A.A.Foad(Faculty of Science, Helwan University, Helwan, Cairo, Egypt) NATL RES CTR DEPT CHEM PHYSCAIROEGYPT HELWAN UNiV FAC SCICAIROEGYPT

The apparent solution dipole moment, μ, the association factor S, and the correlation parameter g for some aldehydes are calculated at different temperatures. The results are discussed and compared with previous results. The dielectric constant ε' and loss ε' for the investigated aldehydes were measured with different frequencies at 10-50℃. The variation of permittivities with both temperature and frequency is discussed. The relaxation times τ, for some aldehydes were calculated at different temperatures and its values were used in the calculation of the thermodynamic parameters △H and △S

关键词： Am Dielectric Properties of Some Aldehydes

Efficiency of Chalcone Compounds inhibitors for Acid Corrosion of Al and Al-3.5mg Alloy

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Journal of materials Science & Technology 1996年第4期12卷 267-272页

作者： i. Z. selim A. A. Khedr and K.m.Ei-Sobki(Physical Chemistry Dept., National Research Centre, Dokki, Cairo, Egypt) Physical Chemistry Dept. National Research Centre Dokki Cairo Egypt

Corrosion inhibition of Al and Al-3.5mg alloy by organic compounds, namely chalcones in hydrochloric acid solutions has been investigated by rapid polarization technique and weight loss method. Polarization measurements show that, the inhibitors act cathodically both in case of Al and Al-3.5mg alloy. it was found from the weight loss measurements that, the inhibition efficiency depends on the substituent in the chalcone compound. The relative inhibitive efficiency of these compounds has been explained on the basis of structure dependent electron donor properties of the inhibitors and the metal inhibitor interaction on the surface. The inhibition efficiency ranges from 16 to 64% for Al and from 30% to 91% for Al-3.5mg alloy

关键词： Al Efficiency of Chalcone Compounds inhibitors for Acid Corrosion of Al and Al-3.5mg Alloy