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

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

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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 performance.This study explores the potential benefits of Al-MOF(MIL-53(Al))energetic additive on the combustion performance of hydroxyl-terminated polybutadiene(HTPB)fuel.The 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 oxidizer.To gauge the effectiveness of Al-MOFs as fuel additives,their impact is compared with that of nano-aluminum(nAl),another traditional additive in HTPB fuel.The 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,respectively.Moreover,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 behavior.In contrast,HTPB-MOF with a 15%Al-MOF additive showed a 32.7%increase in regression rate compared to pure HTPB.These 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

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Optimum insulation thickness and exergy savings of building walls in Bamenda: a comparative analysis

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Energy Storage and Saving 2024年第1期3卷 60-70页

作者： Fodoup Cyrille Vincelas Fohagui Yemeli Wenceslas Kohole Njimboh Henry Alombah Derek Ajesam Asoh Ghislain Tchuen department of Electrical and Electronics Engineering College of TechnologyThe University of BamendaP.O.Box 39BambiliCameroon department of energetic Environment and Thermal EngineeringIUT-FV BandjounUR-ISIEUniversity of DschangP.O.Box 134BandjounCameroon National Higher Polytechnic Institute and Higher Technical Teacher Training College The University of BamendaP.O.Box 39BambiliCameroon

The goal of this study is to examine the energetic,entransy,and exergetic methodologies employed to estimate the ideal insulation thickness for construction walls in terms of cost and ecological impact.To achieve these goals,the life cycle cost analysis-based insulating thicknesses of the various methods are evaluated along with the overall costs,yearly cost reductions,and total expenses.The fuel consumption,CO_(2) emissions,and ecological effects are then compared using an environmental analysis based on the three methodologies.The savings of hollow concrete brick(HCB),compressed stabilized earth brick(CSEB),and sundried earth brick(SEB)walls are evaluated along with the insulation thicknesses in terms of cost and ecological impact.As a result,it is determined that the exergetic technique is better suited for optimizing insulating thickness.For CSEB,SEB,and HCB walls,the economic ideal insulation thicknesses are 0.01 m,0.016 m,and 0.02 m,with yearly financial savings of 5$⋅m^(-2),7.5$⋅m^(-2),and 9$⋅m^(-2).For CSEB,SEB,and HCB walls,accordingly,the ecological optimal insulation thicknesses are 0.023 m,0.032 m,and 0.040 m,with net savings of exergetic ecological impact equal to 59 mPts⋅m^(-2),55 mPts⋅m^(-2),and 51 mPts⋅m^(-2).

关键词： Insulation thickness Environmental impact Entransy Exergy Exergoeconomic

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Chemical design and characterization of cellulosic derivatives containing high-nitrogen functional groups:Towards the next generation of energetic biopolymers

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Defence Technology（防务技术） 2022年第4期18卷 537-546页

作者： Ahmed Fouzi Tarchoun Djalal Trache Thomas M.Klapotke Amir Abdelaziz Mehdi Derradji Slimane Bekhouche energetic Materials Laboratory Teaching and Research Unit of Energetic ProcessesEcole Militaire PolytechniqueBP 17Bordj El-Bahri16046AlgiersAlgeria energetic Propulsion Laboratory Teaching and Research Unit of Energetic ProcessesEcole Militaire PolytechniqueBP 17Bordj El-Bahri16046AlgiersAlgeria department of Chemistry Ludwig Maximilian University Butenandtstrasse 5-13(D)D-81377MunichGermany Process Engineering Laboratory Teaching and Research Unit of Energetic ProcessesEcole Militaire PolytechniqueBP 17Bordj El-Bahri16046AlgiersAlgeria

In this research,a promising class of insensitive and high-energy dense biopolymers,which contain nitrogen-rich 1H-tetrazol-1-yl acetate and nitrate ester functional groups,was successfully synthesized through tetrazole derivatization and nitration of cellulose and its micro-sized derivative(TNCN and TCMCN).Their molecular structures,physicochemical properties,thermal behaviors,mechanical sensitivities and detonation performances were studied and compared to those of the corresponding nitrocellulose and nitrated micro-sized cellulose(NCN and CMCN).The developed energetic TNCN and TCMCN exhibited insensitive character with excellent features such as density of 1.710 g/cm3and 1.726 g/cm3,nitrogen content of 20.95%and 22.59%,and detonation velocity of 7552 m/s and 7786 m/s,respectively,and thereby demonstrate their potential applications as new generation of energetic biopolymers to substitute the common NCN.Furthermore,thermal results showed that the designed nitrated and chemical modified cellulosic biopolymers displayed good thermal stability with multistep decomposition mechanism.These results enrich future prospects for the design of promising insensitive and high-energy dense cellulose-rich materials and commence a new chapter in this field.

关键词： Cellulose Surface functionalization Tetrazole Nitrate ester Nitrogen-rich polymer energetic properties

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Development of bimetallic spinel catalysts for low-temperature decomposition of ammonium dinitramide monopropellants

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Defence Technology（防务技术） 2023年第12期30卷 47-54页

作者： C.Shamjitha Anuj A.Vargeese Laboratory for energetic and Energy Materials Research(LEEMR) Department of ChemistryNational Institute of Technology CalicutKozhikode 673601India

Ammonium dinitramide(ADN)based liquid monopropellants have been identified as environmentally benign substitutes for hydrazine monopropellant.However,new catalysts are to be developed for making ADN monopropellants cold-start capable.In the present study,performance of Co and Ba doped CuCr_2O_4 nanocatalysts prepared by hydrothermal method was evaluated on the decomposition of aqueous ADN solution and ADN liquid monopropellant(LMP103X).The catalysts were characterized by PXRD(Powder X-ray Diffraction),FTIR(Fourier Transform Infrared spectroscopy),SEM(Scanning Electron Microscopy),TEM(Transmission Electron Microscopy),EDS(Energy Dispersive X-ray Spectroscopy),and XPS(X-ray Photoelectron Spectroscopy).The nanosize was confirmed by SEM and TEM,while the nanoflake morphology was confirmed by the SEM analysis.Further,we obtained the elemental composition from the EDS analysis.We investigated the catalytic activity of the catalysts by thermogravimetric(TG)analysis and the developed catalysts lowered the decomposition temperature of ADN monopropellant by about 55℃.The XPS analysis confirmed the presence of metal ions with different chemical states.Apparently,increase in the surface area of the catalysts and the mixed active sites as well as the development of oxygen vacancy on the catalyst surface introduced by metal doping are influencing the decomposition temperature of ADN samples.

关键词： ADN monopropellant Mixed metal oxides Doped spinels Catalytic decomposition

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Measurement of the high energyγ-rays from heavy ion reactions usingČerenkov detector

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Nuclear Science and Techniques 2024年第2期35卷 123-130页

作者： Da-Wei Si Yan Zhou Sheng Xiao Zhi Qin Dong Guo Yu-Hao Qin Yi-Jie Wang Bo-Yuan Zhang Bai-Ting Tian Zhi-Gang Xiao department of Physics Tsinghua UniversityBeijing 100084China

The energetic bremsstrahlung photons up to 100 MeV produced in heavy ion collisions can be used as a sensitive probe for short-range correlation in atomic nuclei. The energy of the γ-rays can be measured by collecting the Čerenkov light in the medium induced by the fast electrons generated in the Compton scattering or electromagnetic shower of the incident γray. Two types of detectors based on pure water and lead glass as sensitive materials were designed for this purpose. The γresponse and optical photon propagation in the detectors were simulated based on electromagnetic and optical processes in Geant4. The inherent energy resolutions of 0.022(4) + 0.51(2)∕E^(1/2)_(γ) for water and 0.0026(3) + 0.446(3)∕E^(1/2)_(γ) for lead glass were obtained. The geometry sizes of the lead glass and water were optimized to 30 cm × 30 cm × 30 cm and 60 cm × 60 cm ×120 cm, respectively, to detect high-energy γ-rays at 160 MeV. The Hough transform method was applied to reconstruct the direction of the incident γ-rays, providing the ability to experimentally distinguish the high-energy γ-rays produced in the reactions on the target from random background cosmic-ray muons.

关键词： Bremsstrahlungγ-rays Čerenkov Geant4 Energy resolution Direction reconstruction Hough transform

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A statistical analysis of the Kappa-type energy spectrum distribution of radiation belt electrons observed by Van Allen Probes

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Earth and Planetary Physics 2024年第2期8卷 368-374页

作者： LuHuai Jiao Xin Ma YuanNong Zhang TaiFeng Jin Song Fu BinBin Ni department of Space Physics School of Electronic InformationWuhan UniversityWuhan 430072China

The energy spectrum of energetic electrons is a key factor representing the dynamic variations of Earth’s Van Allen radiation belts.Increased measurements have indicated that the commonly used Maxwellian and Kappa distributions are inadequate for capturing the realistic spectral distributions of radiation belt electrons.Here we adopt the Kappa-type(KT)distribution as the fitting function and perform a statistical analysis to investigate the radiation belt electron flux spectra observed by the Van Allen Probes.By calculating the optimal values of the key KT distribution parameters(i.e.,κandθ2)from the observed spectral shapes,we fit the radiation belt electron fluxes at different L-shells under different geomagnetic conditions.In this manner,we obtain typical values of the KT distribution parameters,which are statistically feasible for modeling the radiation belt electron flux profiles during either geomagnetically quiet or active periods.A comparison of the KT distribution model results with those using the Maxwellian or Kappa distribution reveals the advantage of the KT distribution for studying the overall properties of the radiation belt electron spectral distribution,which has important implications for deepening the current understanding of the radiation belt electron dynamics under evolving geomagnetic conditions.

关键词： radiation belt electron Kappa-type distribution fitting geomagnetic storm

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Metabolic reprogramming of the inflammatory response in the nervous system:the crossover between inflammation and metabolism

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Neural Regeneration Research 2024年第10期19卷 2189-2201页

作者： Jesus Amo-Aparicio Charles A.Dinarello Ruben Lopez-Vales department of Medicine University of ColoradoAuroraCOUSA Institute of Neurosciences and Department Cell BiologyPhysiology and ImmunologyUniversitat Autònoma de BarcelonaBellaterraSpain Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas(CIBERNED) Instituto de Salud Carlos ⅢSpain

Metabolism is a fundamental process by which biochemicals are broken down to produce energy(catabolism) or used to build macromolecules(anabolism). Metabolism has received renewed attention as a mechanism that generates molecules that modulate multiple cellular responses. This was first identified in cancer cells as the Warburg effect, but it is also present in immunocompetent cells. Studies have revealed a bidirectional influence of cellular metabolism and immune cell function, highlighting the significance of metabolic reprogramming in immune cell activation and effector functions. Metabolic processes such as glycolysis, oxidative phosphorylation, and fatty acid oxidation have been shown to undergo dynamic changes during immune cell response, facilitating the energetic and biosynthetic demands. This review aims to provide a better understanding of the metabolic reprogramming that occurs in different immune cells upon activation, with a special focus on central nervous system disorders. Understanding the metabolic changes of the immune response not only provides insights into the fundamental mechanisms that regulate immune cell function but also opens new approaches for therapeutic strategies aimed at manipulating the immune system.

关键词： central nervous system fatty acid oxidation glycolysis inflammation macrophage metabolism microglia neurodegeneration oxidative phosphorylation

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Thermal Analysis of Melting Occurring Inside a Finned Rectangular Enclosure Equipped with Discrete Pulsed Protruding Heat Sources

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Fluid Dynamics & Materials Processing 2022年第5期18卷 1539-1549页

作者： Brahim Amahan Hamid El Qarnia Ali El Afif Faculty of Sciences Department of PhysicsLaboratory of Innovation in Sciences Technology and ModelingChouaib Doukkali UniversityEl JadidaMorocco Faculty of Sciences Semlalia Fluid Mechanics and Energetic LaboratoryDepartment of PhysicsCadi Ayyad UniversityMarrakeshMorocco

This paper numerically investigates the effect of the location of a horizontal fin on the melting of a phase change material(PCM)inside a rectangular enclosure heated by multiple discrete pulsed protruding heat sources.The fin and the phase change material filling the enclosure store the thermal energy extracted from the heat sources,in sensible and latent forms.The heat sources are assumed to simulate electronic components undergoing a superheating technical issue.By extracting heat from the electronics,the PCM plays the role of a heat sink.To analyze the thermal behavior and predict the cooling performance of the proposed cooling system,we derive a nonlinear mathematical model based on mass,momentum and energy conservation laws.Several numerical investigations are conducted to quantify the influence of the fin position on the thermal behavior and the cooling performance of the heat sink.Predictions include the transient maximum temperature occurring inside the heat sources and the liquid volume.A comparison between our numerical results and experimental data selected from the literature shows a good agreement.The main conclusion is that the presence of the fin leads to a slight increase in the melting time.

关键词： Phase change material melting heat transfer pulsed heating electronics cooling heat storage fin

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Natural parasites in conjunction with behavioral and color traits explain male agonistic behaviors in a lizard

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Current Zoology 2024年第1期70卷 59-69页

作者： Rodrigo Megia-Palma Dhanashree Paranjpe Robert D.Cooper Pauline Blaimont Barry Sinervo department of Biomedicine and Biotechnology Parasitology UnitUniversidad de Alcala(UAH)E-28805Alcala de HenaresSpain CIBio Centro de Investigagao em Biodiversidade e Recursos GeneticosInBIO Laboratorio AssociadoCampus de VairaoUniversidade do PortoP-4485-661 VairaoPortugal BIOPOLIS Program in Genomics Biodiversity and Land PlanningCIBIOCampus de VairaoP-4485-661 VairaoPortugal Rupa Rahul Bajaj Center for Environment and Art Empress Botanical GardensKavade MalaPuneIndia department of Ecology and Evolutionary Biology University of CaliforniaLos AngelesCA 90095USA department of Biology University of Houston Downtown1Main St.HoustonTX 77002USA department of Ecology and Evolutionary Biology University of CaliforniaSanta CruzCA 95064USA

Male competition conforms to a cost-benefit model,because while aggression may increase reproductive prospects,it can also increase the risk of injury.We hypothesize that an additional cost in aggressive males would be an increase in parasite load associated with a high energy investment into sexual competition.Some of these infections,in turn,may downmodulate the level of host aggression via energetic trade-offs.We staged dyadic male contests in the lab to investigate the relationships of multiple parasites with the agonistic behavior of lizard hosts,Sceloporus occidentalis.We also included both color and behavioral traits from opponents in the analyses because(1)color patches of lizards may serve as intraspecific signals used by conspecifics to assess the quality of opponents,and(2)contests between male lizards fit classical models of escalated aggression,where lizards increase aggression displays in response to an opponent's behavior.The results conform to our hypothesis because male lizards displayed more pushups when they had more ticks.Moreover,some parasites may modulate the levels of aggression because lizards infected by hematic coccidians performed fewer pushups.Interestingly,lizards also displayed fewer pushups when both the chroma and size of the opponent's blue patch were greater.The results thus also supported the role of the blue patch of s.occidentalis as a sexual armament,because it contributed to the deterrence of aggression from opponent lizards.We revealed that natural parasitic infections in lizard hosts can contribute to their agonistic behavior.We encourage future studies to account for parasites in behavioral testswithlizards.

关键词： Ixodes pacificus Lankesterella sexual selection social interactions ticks

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