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Ballistic design and testing of a composite armour reinforced by CNTs suitable for armoured vehicles

Defence Technology（防务技术） 2024年第2期32卷 173-195页

作者： Evangelos ch.Tsirogiannis Evangelos Daskalakis Mohamed h.hassan Abdalla M.Omar Paulo Bartolo EODh SA Research and Development DepartmentLakkoma Chalkidikis63080Greece School of Mechanical Aerospace and Civil EngineeringUniversity of ManchesterManchesterM139PLUK Singapore Centre for 3D Printing School of Mechanical and Aerospace EngineeringNanyang Technological University639798Singapore

This paper is investigating the use of composite armour reinforced by nanomaterials, for the protection of light armoured(LAV) and medium armoured military vehicles(MAV), and the interaction between the composite materials and high-performance ballistic projectiles. Four armour materials, consisted of front hybrid fibre reinforced polymer cover layer, ceramic strike-face, fibre reinforced polymer intermediate layer and the metal matrix composite reinforced backplate, were manufactured and assembled by adhesive technology. The proposed laminated protection system is suitable for armoured ground vehicles;however, it could be used as armour on ground, air and naval platforms. The design of the protection system, including material selection and thickness, was elaborated depending on the performance requirements of Level 4 + STANAG 4569 military standard(projectile 14.5 mm × 114 mm API B32) and especially on a design philosophy which is analysed with the specifications. The backplate of this new composite is a hybrid material of Metal Matrix Composite(MMC) reinforced with carbon nanotubes(CNTs), manufactured with the use of powder metallurgy technique. The composite backplate material was morphologically, mechanically and chemically analysed. Results show that all plates are presenting high mechanical properties and ballistic characteristics, compared to commonly used armour plates. Real military ballistic tests according to AEP-STANAG 4569 were carried out for the total composite armour systems. After the ballistic tests, AA2024-CNT3 showed the best protection results, compared with the other plates(AA2024-CNT1 and AA2024-CNT2), with the projectile being unable to fully penetrate the composite plate.

关键词： Passive armour protection Protective armour Ballistic performance hybrid composites Vehicle protection

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Correlation between Total PSA Level and the histoprognostic Gleason Score

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Open Journal of Pathology 2024年第2期14卷 69-80页

作者： Fabrice Senghor Ibou Thiam Kor Ndiaye Kassoum badji Department of Pathological Anatomy H&#244pital de La Paix Ziguinchor Senegal Department of Pathological Anatomy CHU Aristide le Dantec Dakar Senegal

Prostate cancer is a public health problem in Senegal. It is one of the most common cancers in men and can be detected early by PSA measurement and confirmed by the pathological study which specifies the histological type and evaluates the histoprognostic scores (Gleason and pTNM). We did not find any anatomopathological study highlighting a link between the PSA t rate and histoprognostic Gleason scores in Senegal. Objective: We carried out this work aimed at determining whether there is a correlation between the PSA t rate and the histoprognostic Gleason score, in our context. Methodology: This is a retrospective, descriptive and analytical study conducted from January 2013 to October 2021, based on histologically proven prostate cancer cases with a specified PSA level, diagnosed in the pathological anatomy and cytology laboratory of Aristide Le Dantec hospital. Results: We identified 654 cases of prostate cancer. The average age was 68.59 ± 5.8 years with extremes of 40 years to 92 years. More than half of our cohort presented a clinical stage T2c, i.e. 56.94%. The average prostate volume on ultrasound was 81.81 ± 66 cc. The median PSA t was 110.5 ng/ml, with extremes ranging from 2 ng/ml to 74,770 ng/ml. Prostatic adenocarcinoma was the only histological type found in our patients. There was a predominance of Gleason score 6 (PICU grade group 1) observed in 35.17% of patients. Well-differentiated cancers were predominant and represented 35.17%. There was a statistically significant positive correlation between PSA t level and Gleason score (Spearman’s Rho = 0.305, p = 0.000). Conclusion: This study shows that in the Senegalese population, in patients with prostate cancer, the higher the PSA t level rises above normal, the higher the Gleason score tends to be.

关键词： Prostate Cancer PSAt Gleason Dakar

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Management of Acute Bowel Obstruction in Adults in Ziguinchor hospital Establishments: About 163 Cases Followed Up

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Surgical Science 2024年第4期15卷 207-218页

作者： Omar Sow ch.ikh.h. badji Mouhamed Dieng Reymond Seydi Aissata Diallo cheikh Diouf Papa A. Ba Boubacar Fall Department of General Surgery Peace Hospital Assane Seck University of Ziguinchor Ziguinchor Senegal Department of General Surgery Central Regional Hospital of Ziguinchor Assane Seck University of Ziguinchor Ziguinchor Senegal Department of General Surgery University of Iba Der Thiam Thies Senegal

Acute intestinal obstruction represents a very frequent admission to surgical emergencies. The aim of our study was to make a descriptive analysis of the management of acute intestinal obstructions at the level of hospital establishments in Ziguinchor. Materials and Methods: This was a retrospective, descriptive, multicenter study from the period of January 1, 2017 to December 31, 2021. Patients over 15 years of age admitted for occlusive syndrome in the two surgical departments of the Ziguinchor regional hospitals were included in the study. Epidemiological, diagnostic, therapeutic and evolutionary data were studied. Results: Acute intestinal occlusions accounted for 8.3% of admissions. A total of 163 patients were enrolled, 61.9% were men, sex ratio of 1.6. The mean age was 48.7 years. The average consultation time was 74.8 hours (3.12 days). The total occlusive syndrome was in 48.5% of the cases. Abdominal pain was present in 87.1%, vomiting in 74.2%, cessation of matter and gas in 60.7% and meteorism in 36.2%. Biological lab tests reported hyperleukocytosis in 28.1% of the cases. Abdominal CT scans were performed in 71.2%, confirming the diagnosis in 90.5% and determining the etiology in 93.1%. The zone of the obstruction in the small bowel was 62.7%, and in the colon in 37.3%. Functional occlusions accounted for 22.7% of cases and mechanical for 77.3%, including 120 cases of strangulation occlusion (95.2%) and 6 cases of obstruction. Etiologies were dominated by adhesions and/or fibrous bands (61.2%). Medical treatment resolved the occlusive syndrome in 9.2% of cases, instrumental treatment in 17.1% and surgical treatment in 77.3%. Adhesiolysis/section of fibrous bands (55.7%), detorsion (14.3%) and resection anastomosis (11.9%) were the most common surgical procedures. Overall morbidity was 11.6%, dominated by surgical site infection (7.14%). The mean resumption of intestinal transit was 2.7 days, and the mean hospital stay was 7.9 days. Overall mortality was

关键词： Intestinal Obstruction Emergency Surgery Ziguinchor

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Phosphine/Benzocyclone-based Neutral Nickel Catalysts for Ethylene Polymerization and Copolymerization with Polar Monomers

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chinese Journal of Polymer Science 2024年第2期42卷 202-212,I0007页

作者： Fei Wang Li Pan Vladislav A.Tuskaev Svetlana ch.Gagieva Yue-Sheng Li Tianjin Key Lab of Composite&Functional Materials School of Material Science and EngineeringTianjin UniversityTianjin300072China Department of chemistry Lomonosov Moscow State UniversityRussian Federation InstitutionLeninskie Gory 1Moscow119991Russian Federation A N Nesmeyanov Institute of Organoelement Compounds Russian Academy of SciencesVavilova st.28Moscow119991Russian Federation

The efficient copolymerization of olefin with polar monomers using nickel-based catalysts presents a longstanding challenge. In this contribution, three phosphine-benzocyclone ligands and corresponding neutral nickel catalysts(Ni1: Ar = Ph;Ni2: Ar = 2-(C_(6)h_(5))C_(6)h_(4);Ni3: Ar = 2-[2',6'-(Me O)_(2)-C_(6)h3]C_(6)h_(4)) were prepared and applied for the ethylene polymerization and copolymerization with polar monomers without any cocatalyst. The bulky substituent groups in complexes Ni2 and Ni3 contributed to high catalytic activities(up to 7.24×10^(6) and 9.04×10^(6)g·mol Ni^(-1)·h^(-1), respectively), and produced high-molecular-weight polyethylene(Mw up to 545.7 k Da). Complex Ni3 exhibited high activities for ethylene polymerization at the level of 10^(6) g·mol Ni^(-1)·h^(-1) across a wide range from 30 ℃ to 120 ℃, exhibiting excellent high temperature tolerance. These nickel complexes were also effectively employed in the copolymerization of ethylene with methyl acrylate, ethyl acrylate, butyl acrylate and lauryl acrylate, producing copolymers with high molecular weights(Mw up to 80.5 k Da) and high polar monomer incorporation(up to 8.2 mol%). Microstructure analyses revealed that the introduction of large sterically hindered substituents facilitated the incorporation of polar functional units into the polymer backbone. This study demonstrates the potential of these nickel-based catalysts for efficient copolymerization of olefin with polar monomers.

关键词： Neutral nickel catalyst Ethylene polymerization Copolymerization Polar acrylate monomers

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Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.M.FEIZABAD M.h.YAS Department of Mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQM)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQM)

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holographic dark energy in non-conserved gravity theory

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Communications in Theoretical Physics 2024年第4期76卷 126-133页

作者： h R Fazlollahi Institute of Gravitation and Cosmology Peoples Friendship University of Russia(RUDN University)6 Miklukho-Maklaya StMoscow117198Russia

Recently, reconsidering the Rastall idea T_(μ;νν)^(v)=α_(,μ) through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non-conserved gravity theory’ Fazlollahi 2023 Euro. Phys. J. C 83 923. This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy. hence, in this study we have reinvestigated holographic dark energy Ρ_(X)~h^(2) in the non-conserved theory of gravity. In this context, the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field. As shown, due to non-conservation effects on large-scale structures, unlike the original holographic model, our model onsets an acceleration epoch for the current Universe satisfies observations. Moreover, the interaction and viscous scenarios are studied for this model.

关键词： non-conserved gravity covariant form of thermodynamics holographic dark energy

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Novel synthesis of stabilized Bi_(1-x-y)Gd_xDy_yO_(1.5) solid electrolytes with enhanced conductivity for intermediate temperature solid oxide fuel cells(SOFCs)

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Journal of Rare Earths 2024年第10期42卷 1903-1911页

作者： Ahmed h.Ibrahim Yehia M.Abbas h.A.Ayoub Marwa h.Ali Mustafa Aldoori Materials Science Laboratory Physics DepartmentFaculty of ScienceSuez Canal University41522IsmailiaEgypt Ministry of higher Education and Scientific Research Aliraqia University10011BaghdadIraq

herein,we report the synthesis of a Dy-Gd co-doped cubic phase-stabilized Bi_(2)O_(3) solid electrolyte system via solid-state processing under atmospheric *** with Dy^(3+) and Gd^(3+) has been observed to significantly enhance the densification process during sintering for stabilization purposes,thereby improving the electrical properties of δ-Bi_2O_(3)-type *** synthesized ceramics were characterized using X-ray diffraction(XRD),field emission scanning electron microscopy-energy dispersive X-ray spectroscopy(FESEM-EDX),thermal gravimetry/differential thermal analysis(TG/DTA),and the four-point probe technique(4PPT).XRD analysis reveals that the samples Bi_(1-x-y)Gd_(x)Dy_(y)O_(1.5)(y=0.05/x=0.05,0.10,0,15,and 0.20,and x=0.05/y=0.10,0.15,and 0.20) exhibit a stable face-centered cubic δ-phase and a mixed-phase crystallographic *** XRD analysis of the stabilized δ-phase suggests that the prepared oxides show a face-centered cubic(FCC) structure with a space group of *** micrographs reveal that the composition Bi_(0.90)Gd_(0.05)Dy_(0.05)O_(1.5) has no significant ***,an evident increase in the pore formation is observed as the amount of Gd_(2O_(3) increases until it reaches 20%.This finding suggests that dense pellets are formed during the sintering process at 900-1000℃.The DTA analyses were performed to verify the phase stability,which agrees with the XRD *** electrochemical performance of the synthesized Dy-Gd co-doped Bi_2O_(3)solid electrolyte system was evaluated and analyzed in detail by using the electrochemical impedance spectroscopy(EIS) technique,Based on EIS and conductivity measurements,Bi_(0.75)Gd_(0.20)Dy_(0.05)O_(1.5) exhibits the lowest activation energy of 0.519 eV and the highest conductivity value of 0.398 S/cm at 627℃compared to the other samples;this composition can be used as a solid electrolyte for intermediatetemperature solid oxide fuel cells(SOFCs).

关键词： Solid oxide fuel cells(SOFCs) Rare earths Solid-state processing Rietveld Fast Fourier transform(FFT) Electrochemical impedance spectroscopy(EIS)

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Solid-liquid extraction for yttrium recovery using porous polymeric resin(XAD-7) functionalized with D_(2)EhPA

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Journal of Rare Earths 2024年第9期42卷 1764-1773,I0005页

作者： P.A.Martínez-Montoya R.G.Sanchez-Alvarado D.Y.Medina-Velazquez M.L.Carrera-Jota P.Garnica-chávez A.de J.Morales-Ramirez higher School of chemical Engineering and Extractive Industries ESIQIEIPNDepartment of Metallurgical EngineeringUPALM S/NCol.LindavistaGustavo A.Madero Cd.de MéxicoC.P07738Mexico Metropolitan Autonomous University Department of MaterialsBasic Sciences and EngineeringAv.San Pablo No.180Col.Reynosa TamaulipasCd.de MéxicoC.P02200Mexico Center for Research and Technological Innovation CIITECIPNCda.de CECATIs/nSanta CatarinaAzcapotzalcoC.P02250CDMXMexico

The recovery of yttrium is proposed by applying a solid-liquid extraction process using di-2-ethyl hexylphosphoric acid(D2EhPA) as extracting *** extracting agents were supported on a macro porous polymeric resin XAD-7(solid phase).Yttrium ions extraction and discharge tests were performed,firstly from a synthetic aqueous solution of 100 mg/L Y(liquid phase) at 25℃ with *** effects of ph of aqueous solutions bearing yttrium,volume fraction of extracting agents and the solid/liquid(S/L)ratio on the yttrium recovery were *** most favorable conditions for yttrium ions extraction are;20 vol% D_(2)EhPA functionalized resin,ph=1.5 and an S/L ratio of 10 mg/mL The discharge of yttrium ions was done under the same conditions of extraction stage,using a 2 mol/L [h_(2)SO_(4)] as stripping *** to 80% yttrium is extracted,while 75% yttrium is recovered in the striping *** all experiments,the reaction equilibrium is reached after 20 min,and the kinetics for the extraction stage was determined as a second-order ***,experiments were carried out to discharge the yttriumloaded resins,and it has been determined that the best ph value to strip the Y ions is *** tests of extraction and discharge for yttrium ions show that the functionalized resin can work at least five cycles without decreasing its ***,the proposed process was tested in a real solution with Y ions fro m a waste fluorescent la mp powder leached in h_(2)SO_(4),demonstrating the ability to effectively recover yttrium,separating it from various metals from the studied residue.

关键词： Yttrium recovery Rare earth solid-liquid extraction XAD-7 resin Fluorescent lamps recycling Solid-liquid kinetics extraction

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Shell-model representations of the microscopic version of the Bohr-Mottelson collective model

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Communications in Theoretical Physics 2024年第8期76卷 79-90页

作者： h G Ganev Joint Institute for Nuclear Research DubnaRussia Institute of Mechanics Bulgarian Academy of SciencesSofiaBulgaria

The structure of the irreducible collective spaces of the group Sp(12,R),which many-particle nuclear states are classified according to the chain Sp(12,R)⊃U(6)⊃SO(6)⊃SU_(pn)(3)⊗SO(2)⊃SO(3)of the proton-neutron symplectic model(PNSM),is considered in *** chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr-Mottelson collective *** construction of the relevant shell-model representations of the Sp(12,R)group along this chain is considered for three nuclei with varying collective properties and from different mass *** is shown that the SU_(pn)(3)basis states of the Sp(12,R)representations belonging to the SO(6)irreps with seniorityυ≥υ0,withυ0 denoting the maximal seniority SO(6)irrep contained in the Sp(12,R)bandhead,are always Pauli allowed,but organized in a different way into different SO(6)*** is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm *** the SU_(pn)(3)multiplets withinυhe present work are important for the practical application of the microscopic version of the Bohr-Mottelson collective model.

关键词： microscopic shell-model version of the Bohr-Mottelson model proton-neutron symplectic model Sp(12,R)dynamical algebra shell-model representations

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Convexification of hybrid AC-DC Optimal Power Flow with Line-Commutated Converters

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 617-628页

作者： hongyuan Liang Zhigang Li J.h.Zheng Q.h.Wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China

Line-commutated converter (LCC)-based high-voltage DC (hVDC) systems have been integrated with bulk AC power grids for interregional transmission of renewable power. The nonlinear LCC model brings additional nonconvexity to optimal power flow (OPF) of hybrid AC-DC power grids. A convexification method for the LCC station model could address such nonconvexity but has rarely been discussed. We devise an equivalent reformulation for classical LCC station models that facilitates second-order cone convex relaxation for the OPF of LCC-based AC-DC power grids. We also propose sufficient conditions for exactness of convex relaxation with its proof. Equivalence of the proposed LCC station models and properties, exactness, and effectiveness of convex relaxation are verified using four numerical simulations. Simulation results demonstrate a globally optimal solution of the original OPF can be efficiently obtained from relaxed model.

关键词： AC-DC power system convex relaxation linecommutated converter optimal power flow second-order cone programming

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