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Unraveling the role of dual Ti/mg metals on the ignition and combustion behavior of HTPB-boron-based fuel

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Defence Technology（防务技术） 2024年第2期32卷 134-143页

作者： Arijit Debnath Yash Pal sri Nithya mahottamananda Djalal Trache School of Aeronautical Science Hindustan Institute of Technology and ScienceChennai 603103India Department of Aerospace Engineering B S Abdur Rahman Crescent Institute of Science and TechnologyChennai 600048India Energetic materials Laboratory(EmLab) Teaching and Research Unit of Energetic ProcessesEcole Militaire PolytechniqueBP 17Bordj El-Bahri16046AlgiersAlgeria

metal additives play an essential role in explosive and propellant formulations. Boron(B) is widely used in propellant applications owing to its high energetic content. The addition of B to explosives and propellants increases their energy density, making them more efficient and powerful. Nevertheless, B forms oxide layers on its surface during combustion, slowing down the combustion rate and reducing rocket motor efficiency. To overcome this issue, other metal additives such as aluminum(Al), magnesium(mg),and titanium(Ti) are revealed to be effective in boosting the combustion rate of propellants. These additives may improve the combustion rate and therefore enhance the rocket motor’s performance. The present study focused on preparing and investigating the ignition and combustion behavior of pure hydroxyl-terminated polybutadiene(HTPB)-B fuel supplemented with nano-titanium and nanomagnesium. The burn rates of HTPB-B fuel samples were evaluated on the opposed flow burner(OFB)under a gaseous oxygen oxidizer, for which the mass flux ranges from 22 kg/(m^(2)·s) to 86 kg/(m^(2)·s). The addition of Ti and mg exhibited higher regression rates, which were attributed to the improved oxidation reaction of B due to the synergetic metal combustion effect. The possible combustion/oxidation reaction mechanism of B-mg and B-Ti by heating the fuel samples at 900℃ and 1100℃ was also examined in a Nabertherm burnout furnace under an oxygen atmosphere. The post-combustion products were collected and further subjected to X-ray diffraction(XRD) and field emission scanning electron microscopy(FE-SEm) analyses to inspect the combustion behavior of B-Ti and B-mg. It has been observed that the B oxide layer at the interface between B-Ti(B-mg) is removed at lower temperatures, hence facilitating oxygen transfer from the surroundings to the core B. Additionally, Ti and mg decreased the ignition delay time of B, which improved its combustion performance.

关键词： Boron B_(2)O_(3) Opposed flow burner Combustion magnesium

Evaluating Ignition and Combustion Performance with Al-metal- Organic Frameworks and Nano-Aluminum in HTPB Fuel

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火炸药学报 2024年第5期47卷 413-421,I0003页

作者： sri Nithya mahottamananda Yash Pal Yarravarapu Sai sriram Subha S Djalal Trache Department of Aerospace Engineering B S Abdur Rahman CrescentInstitute of Science and TechnologyChennai-600048India School of Aeronautical Science Hindustan Institute of Technologyand ScienceChennai-603103India Energetic materials Laboratory(EmLab) Teaching and ResearchUnit of Energetic ProcessesEcole Militaire PolytechniqueBP 17Bordj El-Bahri16046AlgiersAlgeria

Incorporating aluminum metal-organic frameworks(Al-mOFs)as energetic additives for solid fuels presents a promising avenue for enhancing combustion *** study explores the potential benefits of Al-mOF(mIL-53(Al))energetic additive on the combustion performance of hydroxyl-terminated polybutadiene(HTPB)*** HTPB-mOF fuel samples were manufactured using the vacuum-casting technique,followed by a comprehensive evaluation of their ignition and combustion properties using an opposed flow burner(OFB)setup utilizing gaseous oxygen as an *** gauge the effectiveness of Al-mOFs as fuel additives,their impact is compared with that of nano-aluminum(nAl),another traditional additive in HTPB *** results indicate that the addition of 15%(mass fraction)nAl into HTPB resulted in the shortest ignition delay time(136 ms),demonstrating improved ignition performance compared to pure HTPB(273 ms).The incorporation of Al-mOF in HTPB also reduced ignition delay times to 227 ms and 189 ms,***,under high oxidizer mass flux conditions(79—81 kg/(m^(2)s)),HTPB fuel with 15%nAl exhibited a substantial 83.2%increase in regression rate compared to the baseline HTPB fuel,highlighting the positive influence of nAl on combustion *** contrast,HTPB-mOF with a 15%Al-mOF additive showed a 32.7%increase in regression rate compared to pure *** results suggest that HTPB-nAl outperforms HTPB-mOF in terms of regression rates,indicating a more vigorous and rapid burning behavior.

关键词： ignition combustion enhancement mOF HTPB regression rate

Praseodymium metal nanorods as a 5-fluorouracil carrier

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Journal of Rare Earths 2024年第7期42卷 1328-1336,I0005页

作者： Varnitha manikantan Govindaraj sri Varalakshmi Ujma Ashapak Tamboli Archana Sumohan Pillai Aleyamma Alexander Anushka Lucas Bose Allben Akash Israel V.m.V.Enoch Centre for Nanoscience and Genomics Karunya Institute of Technology and Sciences(Deemed University)Coimbatore641114Tamil NaduIndia Department of Applied Chemistry Karunya Institute of Technology and Sciences(Deemed University)Coimbatore641114Tamil NaduIndia

Interest in metal nanoparticles as nanoscale drug-carrying vehicles has been *** such an aspect,lanthanide metal nanoparticles are particularly ***,we report praseodymium nanoparticles as a novel anticancer therapeutic transporting *** material was made as a composite with the supramolecular host polymer,poly-β-*** praseodymium nanorods were characterized using standard analytical techniques,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and thermogravimetric analysis(TGA).In addition,they were imaged using transmission electron *** nanostructures are a long rod-shaped material with 2.0±0.1μm in length and 230±10 nm in *** material shows a saturation magnetization value above 30 emu/g with a coercivity value of 130 *** nanocarrier is freighted with the drug 5-fluorouracil,and the encapsulation efficiency is 76.09%.The drug release is continuous from the nanocarrier(polymer-containing praseodymium nanoparticles)and proceeds for above 250 *** in vitro cytotoxicities of the blank nanocarrier and the 5-fluorouracil-loaded one are deduced by testing them on mCF-7 and Vero(non-cancerous)cell *** cytotoxicity on the cancerous cell lines is observed,whereas the non-cancerous cells are *** IC_(50)values on the cell lines are reported.

关键词： metal nanoparticles Praseodymium Poly-cyclodextrin Drug delivery Anticancer activity Rare earths

Simulation and experimentation of Propeller-Savonius turbine tested underwater surface

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Clean Energy 2024年第3期8卷 20-33页

作者： sri Wuryanti Teguh Sasono Bambang P.manunggal Wahyu B.mursanto Sugianto Department of Energy Conversion Engineering Politeknik Negeri BandungIndonesia Department of mechanical Engineering Politeknik Negeri BandungIndonesia

Indonesia’s vast maritime territory offers a unique opportunity for harnessing the potential Energy of seawater *** study explores the effectiveness of a combined Savonius and propeller-type turbine *** Savonius turbine,known for its efficiency in capturing ocean currents due to its large sweep area,is combined with a propeller-type turbine to enhance rotational speed and power generation.A novel approach is employed to induce turbulence and optimize energy extraction,first channeling water through the propeller turbine and then into the Savonius turbine.A comprehensive investigation is conducted through simulations and experimental tests within a controlled tunnel *** study explores the performance of two-bladed and three-bladed Propeller-Savonius configurations at varying inlet water velocities(0.1,0.3,0.6 and 1.0 m/s).The simulation incorporates a turbulence model with 5%intensity and a hydraulic diameter of 0.216 *** indicate that the proposed configuration achieves a maximum power output of 2.0293 W with an impressive efficiency of 63.339%in ***,experimental testing yields a peak efficiency of 61.335%and turbine power of 0.3951 *** findings demonstrate the feasibility of the combined turbine system and highlight the importance of turbulence in optimizing energy extraction from seawater *** research contributes valuable insights into the design and performance of hybrid turbines for harnessing oceanic Energy,emphasizing the potential for sustainable power generation in maritime *** methodology and results presented herein offer a foundation for further exploration and refinement of seawater current energy conversion technologies.

关键词： hydro-turbine propeller-Savonius renewable energy water

Laparoscopic plication for diaphragmatic eventration in adults:Unveiling the mystery of eventration

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Laparoscopic, Endoscopic and Robotic Surgery 2024年第2期7卷 92-96页

作者： Balika mahesan Prasanna Kumar Reddy K.S.Santhosh Anand muvva sri Harsha m Vijay N Sudarsan srikanth Department of minimal Access Surgery Apollo HospitalsChennaiIndia Department of Surgical Gastroenterology Apollo HospitalsChennaiIndia

Diaphragm eventration is the permanent elevation of a hemidiaphragm and can be due to congenital or acquired *** is a rather uncommon condition in adults and causes a spectrum of symptoms,ranging from asymptomatic incidental findings on imaging to life-threatening respiratory *** patients do not require any treatment,but plication is the conventional,well-known method for treating symptomatic *** varies depending on the *** this article,we discuss two rare cases of diaphragmatic eventration that were treated with minimal access surgery.

关键词： Diaphragmatic eventration minimal access surgeryLaparoscopy

Finite Deformation, Finite Strain Nonlinear Dynamics and Dynamic Bifurcation in TVE Solids with Rheology

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Applied mathematics 2024年第1期15卷 108-168页

作者： Karan S. Surana sri Sai Charan mathi Department of mechanical Engineering University of Kansas Lawrence US

This paper presents a mathematical model consisting of conservation and balance laws (CBL) of classical continuum mechanics (CCm) and ordered rate constitutive theories in Lagrangian description derived using entropy inequality and the representation theorem for thermoviscoelastic solids (TVES) with rheology. The CBL and the constitutive theories take into account finite deformation and finite strain deformation physics and are based on contravariant deviatoric second Piola-Kirchhoff stress tensor and its work conjugate covariant Green’s strain tensor and their material derivatives of up to order m and n respectively. All published works on nonlinear dynamics of TVES with rheology are mostly based on phenomenological mathematical models. In rare instances, some aspects of CBL are used but are incorrectly altered to obtain mass, stiffness and damping matrices using space-time decoupled approaches. In the work presented in this paper, we show that this is not possible using CBL of CCm for TVES with rheology. Thus, the mathematical models used currently in the published works are not the correct description of the physics of nonlinear dynamics of TVES with rheology. The mathematical model used in the present work is strictly based on the CBL of CCm and is thermodynamically and mathematically consistent and the space-time coupled finite element methodology used in this work is unconditionally stable and provides solutions with desired accuracy and is ideally suited for nonlinear dynamics of TVES with memory. The work in this paper is the first presentation of a mathematical model strictly based on CBL of CCm and the solution of the mathematical model is obtained using unconditionally stable space-time coupled computational methodology that provides control over the errors in the evolution. Both space-time coupled and space-time decoupled finite element formulations are considered for obtaining solutions of the IVPs described by the mathematical model and are presented i

关键词： Thermoviscoelasticity Rheology memory Finite Strain Finite Deformation Nonlinear Dynamics Dynamic Bifurcation Ordered Rate Theories

An evaluation of force-based design *** displacement-based design of jointed precast post-tensioned wall systems

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Earthquake Engineering and Engineering Vibration 2006年第2期5卷 285-296页

作者： m. Ataur Rahman sri sritharan 414 Town Engineering building Iowa State University Ames IA 50011 USA 406 Town Engineering building Iowa State University Ames IA 50011 USA Associate Professor

The unique features of jointed post-tensioned wall systems, which include minimum structural damage and re-centering capability when subjected to earthquake lateral loads, are the result of using unbonded post-tensioning to attach the walls to the foundation, along with employing energy dissipating shear connectors between the walls. Using acceptance criteria defined in terms of inter-story drift, residual drift, and floor acceleration, this study presents a multiplelevel performance-based seismic evaluation of two five-story unbonded post-tensioned jointed precast wall systems. The design and analysis of these two wall systems, established as the direct displacement-based and force-based solutions for a prototype building used in the PREcast Seismic Structural Systems （PRESSS） program, were performed at 60% scale so that the analysis model could be validated using the PRESSS test data. Both buildings satisfied the performance criteria at four levels of earthquake motions although the design base shear of the direct displacement-based jointed wall system was 50% of that demanded by the force-based design method. The study also investigated the feasibility of controlling the maximum transient inter-story drift in a jointed wall system by increasing the number of energy dissipating shear connectors between the walls but without significantly affecting its re-centering capability.

关键词： concrete precast unbonded post-tensioning wall building code performance-based evaluation force-baseddesign direct-displacement based design

SHOCK AND BOUNDARY STRUCTURE FORmATION BY SPECTRAL-LAGRANGIAN mETHODS FOR THE INHOmOGENEOUS BOLTZmANN TRANSPORT EQUATION

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Journal of Computational mathematics 2010年第4期28卷 430-460页

作者： Irene m.Gamba sri Harsha Tharkabhushanam Department of mathematics & Institute of Computational Engineering and Sciences University of Texas Austin Institute of Computational Engineering and Sciences University of Texas Austin

The numerical approximation of the Spectral-Lagrangian scheme developed by the authors in [30] for a wide range of homogeneous non-linear Boltzmann type equations is extended to the space inhomogeneous case and several shock problems are benchmark. Recognizing that the Boltzmann equation is an important tool in the analysis of formation of shock and boundary layer structures, we present the computational algorithm in Section 3.3 and perform a numerical study case in shock tube geometries well modeled in for ID in x times 3D in v in Section 4. The classic Riemann problem is numerically analyzed for Knudsen numbers close to continuum. The shock tube problem of Aoki et al [2], where the wall temperature is suddenly increased or decreased, is also studied. We consider the problem of heat transfer between two parallel plates with diffusive boundary conditions for a range of Knudsen numbers from close to continuum to a highly rarefied state. Finally, the classical infinite shock tube problem that generates a non-moving shock wave is studied. The point worth noting in this example is that the flow in the final case turns from a supersonic flow to a subsonic flow across the shock.

关键词： Spectral Numerical methods Lagrangian optimization FFT Boltzmann Trans- port Equation Conservative and non-conservative rarefied gas flows.

magnesium oxide(mgO)nanoadsorbents in wastewater treatment:A comprehensive review

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Journal of magnesium and Alloys 2024年第5期12卷 1709-1773页

作者： H.C.S.Perera V.Gurunanthanan Anoop Singh m.m.m.G.P.G.mantilaka G.Das Sandeep Arya Department of Physics Khalifa UniversityAbu Dhabi12788United Arab Emirates Postgraduate Institute of Science University of PeradeniyaPeradeniyaSri Lanka Department of Humanities and Sciences Guru Nanak Institutions Technical CampusIbrahimpatnamHyderabad501506India Centre for Global Health Research Saveetha Medical College and HospitalsSaveetha Institute of Medical and Technical SciencesChennai602105Tamil NaduIndia Department of Physics University of JammuJammu and Kashmir180006India

Wastewater contamination by heavy metals and synthetic dyes presents a significant environmental challenge,necessitating effective and sustainable separation *** review article provides a detailed examination of magnesium oxide(mgO)nanoparticles as an innovative nanoadsorbent for wastewater treatment,with a specific focus on heavy metal and dye *** review comprehensively explores various aspects of mgO nanoparticles,including their structural characteristics and synthesis *** article delves into the morphology and crystallographic arrangement of mgO nanoparticles,offering insights into their structural *** the complexity of adsorption processes,the review identifies and analyzes parameters influencing the adsorption efficiency of mgO nanoparticles,such as temperature,pH,contact time,initial concentration,and co-existing *** interplay between these parameters and the adsorption capability of mgO nanoparticles emphasizes the importance of optimizing operational ***,the review assesses various synthesis methods for mgO nanoparticles,including sol-gel,hydrothermal,precipitation,green synthesis,solvothermal,and template-assisted *** discusses the advantages,limitations,and resulting nanoparticle characteristics of each method,enabling readers to grasp the implications of synthesis processes on adsorption *** comprehensive review consolidates current insights into the effectiveness of mgO nanoparticles as a potent nanoadsorbent for removing heavy metals and dyes from wastewater covering a wide spectrum of aspects related to mgO ***,there is a need to investigate the use of mgO in the treatment of actual wastewater or river water,in order to leverage its cost-effectiveness and high efficiency for practical water treatment applications in real-time.

关键词： mgO nanoparticles Nanoadsorbent Wastewater treatment Heavy metals Dye separation Adsorption Synthesis methods