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Service life prediction of AP/Al/HTPB solid rocket propellant with consideration of softening aging behavior

Chinese Journal of Aeronautics 2019年第2期32卷 361-368页

作者： Walid m.adel Guozhu LIANG School of Astronautics Beihang University

The aging behavior of softening composite solid propellant was investigated by measuring its mechanical and ballistic prosperities during prolonged storage at elevated and room temperatures. Accelerated aging was conducted at 65 °C for 231 days while the normal aging was performed at 25 ± 3 °C and relative humidity less than 50% for 8 years. The mechanical properties were obtained from uniaxial tensile tests for the aged propellant specimens while the ballistic properties were determined from static firing tests of subscale motors aged for 112 days at 65 °C. The mechanical results show that the maximum tensile strength and Young's modulus initially increase and subsequently decrease with increasing aging time, while the maximum tensile strain generally increases with increasing aging time. The ballistic properties like burning rate show a small change which cannot affect the ballistic performance. The experimental results show that the changes in the mechanical properties are significant during the aging period, but the burning rate does not undergo significant changes. From this study, it is observed that the propellant ages through a combination of reactions like post-cure, oxidative cross-linking, chain scission, and hydrolysis. The chain scission and the hydrolysis effect are the most significant process, which makes the propellant soft and extendible. The observed aging mechanism has been modeled using an exponential function with two terms which can describe the complex behavior of the aging. By applying Arrhenius equation,the activation energy values were obtained based on the propellant mechanical properties. The shelf life of this propellant formulation at 25 °C is predicted to be 13 years using the modulus as failure criteria and control parameter.

关键词： Aging Hydrolysis Service life Softening behavior Solid propellant

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The asymptotic behavior for a binary alloy in energy and material science:The unified method and its applications

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Journal of Ocean Engineering and Science 2024年第4期9卷 373-378页

作者： m.adel K.Aldwoah F.Alahmadi m.S.Osman Department of mathematics Faculty of ScienceIslamic University of MadinahMedinaSaudi Arabia Department of mathematics Faculty of ScienceCairo UniversityGiza 12613Egypt

The Cahn-Hilliard system was proposed to the first time by Chan and Hilliard in *** model(or system of equations)has intrinsic participation energy and materials sciences and depicts significant characteristics of two phase systems relating to the procedures of phase separation when the temperature is *** instance,it can be noticed when a binary alloy(“Aluminum+Zinc”or“Iron+Chromium”)is cooled down *** this case,partially or totally nucleation(nucleation means the appearance of nuclides in the material)is observed:the homogeneous material in the initial state gradually turns into inhomogeneous,giving rise to a very accurate dispersive ***,when the time scale is slower the microstructure becomes *** this work,to the first time,the unified method is presented to investigate some physical interpretations for the solutions of the Cahn-Hilliard system when its coefficients varying with time,and to show how phase separation of one or two components and their concentrations occurs dynamically in the ***,2D and 3D plots are introduced to add more comprehensive study which help to understand the physical phenomena of this *** technique applied in this analysis is powerful and efficient,as evidenced by the computational work and *** technique can also solve a large number of higher-order evolution equations.

关键词： Cahn-Hilliard system Traveling wave solutions The unified method Variable coefficients

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Chitosan/Nanocrystalline Cellulose Biocomposites Based on Date Palm (Phoenix Dactylifera L.) Sheath Fibers

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Journal of Renewable materials 2019年第6期7卷 567-582页

作者： Abeer m.adel Amira m.El-Shafei Atef A.Ibrahim mona T.Al-Shemy Cellulose and Paper Department National Research Center33El-Bohouth St.(Former El-Tahrir St.)DokkiP.O.12622GizaEgypt Textile Research Division National Research Center33El-Bohouth St.(Former El-Tahrir St.)DokkiP.O.12622GizaEgypt

In this study,nanocrystalline celluloses were used to enhance physical,mechanical and water vapor barrier properties of chitosan films for potential food packaging *** different mineral acids(sulfuric and phosphoric)were used to extract nanocrystalline cellulose from date palm sheath *** influence of cellulose I and cellulose II on the properties of the isolated nanocrystalline celluloses(e.g.,yield,energy and length of intra-and intermolecular hydrogen bonds,and degree of substitution)were studied *** characteristics of chitosan biocomposite film with phosphorylated nanocrystalline cellulose were compared to those with sulfated nanocrystalline *** showed that besides cellulose polymorphism,the ionic ester groups on the surface of nanocrystalline cellulose is one of the factors influencing the physical,chemical,mechanical,and water vapor barrier properties in chitosan/nanocrystalline cellulose biocomposites.

关键词： Biocomposite Cellulose I Cellulose II Nanocrystalline cellulose(NCC) physico-mechanical properties Thermal stability

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Feasibility and reliability of the revised Edmonton Symptom Assessment System(ESAS-r)in Egyptian patients with advanced cancer:A single institutional experience

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Oncology and Translational medicine 2016年第2期2卷 132-137页

作者： Dina A.Salem Azza m.adel Ahmed E.Essa mohamed O Alorabi Zeinab m.Elsayed Department of Clinical Oncology Ain Shams University HospitalsCairoEgypt

Objective This study aims to test the acceptance, feasibility, and usefulness of the Arabic version of the revised Edmonton Symptom AssesSment System （ESAS-r） among Egyptian patients with advanced cancer and to compare the rates of symptoms documented by patients and physicians. methods Between August 2014 and February 2015, a total of 140 patients at Ain Shams University Hospitals in Cairo, Egypt received the Arabic version of the ESAS-r. For each patient, the ESAS-r was completed twice, first by the treating physician （as part of the basic assessment） and a second time by the patient, with a maximum of 2 hours between the two assessments. An additional survey was included to assess patients＇ acceptance of the survey and their preferences. Results Out of 140 enrolled patients in the study, 11 patients refused to complete the questionnaire, and 10 patients were excluded due to incomplete records in their medical records. Complete data was retrieved for 119 patients who were included for further analyses. The 78 （65%） patients declared that the test was clear and easy to complete. They were able to answer the test without help. Collectively, tiredness and sense of well-being were the most commonly encountered symptoms in ratings obtained by both patients and physicians. Tiredness was the only symptom showing a significant difference between the two rating methods, patient-rated scores being higher （P = 0.032）. Cronbach＇s alpha showed that both tests com- pleted by the physician and the patients were internally consistent： the physician-rated test had a coefficient of 0.877, and the patient-rated test had a coefficient of 0.863. All ESAS scores had good internal consis- tency, with a Cmnbach＇s alpha coefficient of 0.88. The internal consistency remained high after removal of individual symptom scores, with Cronbach＇s alpha coefficients ranging from 0.823 to 0.902, indicating that no individual question had undue influence on the total ESAS score. Conclusion The ESAS-r

关键词： advanced cancer palliative care Egypt Edmonton Symptom Assessment System (ESAS)

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Stability Prediction in Smart Grid Using PSO Optimized XGBoost Algorithm with Dynamic Inertia Weight Updation

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Computer modeling in Engineering & Sciences 2025年第1期142卷 909-931页

作者： adel Binbusayyis mohemmed Sha Department of Software Engineering College of Computer Engineering and Sciences in Al-Kharj Prince Sattam Bin Abdulaziz UniversityAl-Kharj11942Saudi Arabia

Prediction of stability in SG(Smart Grid)is essential in maintaining consistency and reliability of power supply in grid *** the fluctuations in power generation and consumption patterns of smart cities assists in effectively managing continuous power supply in the *** also possesses a better impact on averting overloading and permitting effective energy *** though many traditional techniques have predicted the consumption rate for preserving stability,enhancement is required in prediction measures with minimized *** overcome the complications in existing studies,this paper intends to predict stability from the smart grid stability prediction dataset using machine learning *** accomplish this,pre-processing is performed initially to handle missing values since it develops biased models when missing values are mishandled and performs feature scaling to normalize independent data ***,the pre-processed data are taken for training and *** that,the regression process is performed using modified PSO(Particle Swarm Optimization)optimized XGBoost Technique with dynamic inertia weight update,which analyses variables like gamma(G),reaction time(tau1–tau4),and power balance(p1–p4)for providing effective future stability in *** PSO attains optimal solution by adjusting position through dynamic inertial weights,it is integrated with XGBoost due to its scalability and faster computational speed *** hyperparameters of XGBoost are fine-tuned in the training process for achieving promising outcomes on *** results are measured through evaluation metrics such as mSE(mean Square Error)of 0.011312781,mAE(mean Absolute Error)of 0.008596322,and RmSE(Root mean Square Error)of 0.010636156 and mAPE(mean Absolute Percentage Error)value of 0.0052 which determine the efficacy of the system.

关键词： Smart Grid machine learning particle swarm optimization XGBoost dynamic inertia weight update

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mesoporous WO_3-graphene photocatalyst for photocatalytic degradation of methylene Blue dye under visible light illumination

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Journal of Environmental Sciences 2018年第4期30卷 328-337页

作者： adel A.Ismail m.Faisal adel Al-Haddad Wastewater Treatment and Reclamation Technologies (WTRT) Water Research Center Kuwait Institute for Scientific Research Advanced materials and Nano-Research Centre Najran University

Advanced oxidation technologies are a friendly environmental approach for the remediation of industrial wastewaters. Here, one pot synthesis of mesoporous WO3 and WO3-graphene oxide（GO） nanocomposites has been performed through the sol–gel method. Then, platinum（Pt） nanoparticles were deposited onto the WO3 and WO3-GO nanocomposite through photochemical reduction to produce mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites. X-ray diffraction（XRD） findings exhibit a formation of monoclinic and triclinic WO3 phases. Transmission Electron microscope（TEm） images of Pt/WO3-GO nanocomposites exhibited that WO3 nanoparticles are obviously agglomerated and the particle sizes of Pt and WO3 are ~ 10 nm and 20–50 nm, respectively. The mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites were assessed for photocatalytic degradation of methylene Blue（mB） as a probe molecule under visible light *** findings showed that mesoporous Pt/WO3, WO3-GO and Pt/WO3-GO nanocomposites exhibited much higher photocatalytic efficiencies than the pure WO3. The photodegradation rates by mesoporous Pt/WO3-GO nanocomposites are 3, 2 and 1.15 times greater than those by mesoporous WO3, WO3-GO, and Pt/WO3, respectively. The key factors of the enhanced photocatalytic performance of Pt/WO3-GO nanocomposites could be explained by the highly freedom electron transfer through the synergetic effect between WO3 and GO sheets, in addition to the Pt nanoparticles that act as active sites for O2 reduction, which suppresses the electron hole pair recombination in the Pt/WO3-GO nanocomposites.

关键词： mesoporous Pt/WO3 nanocomposites Graphene oxide methylene Blue photodegradation Visible light

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Integration of automatic voltage regulator and power system stabilizer: small-signal stability in DFIG-based wind farms

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Journal of modern Power Systems and Clean Energy 2019年第5期7卷 1115-1128页

作者： Sirine ESSALLAH adel BOUALLEGUE adel KHEDHER Universite de Sousse Ecole Nationale d’Ingenieurs de SousseLATIS-Laboratory of Advanced Technology and Intelligent Systems4023 SousseTunisia

The increasing penetration of wind farms in the energy sector directly affects the dynamic behavior of the power *** increasing use of wind energy in the power system worsens its stability and inherently influences the firmness of a small *** investigate these effects,one of the synchronous generators(SGs)of the grid is considered defective and is replaced by a doubly fed induction generator(DFIG)-based wind farm of the same *** small-signal stability of a power system is usually evaluated via eigenvalue analysis where local-area and inter-area oscillatory modes for the New England test system are *** controls,such as automatic voltage regulator(AVR)and power system stabilizer(PSS),are added to attenuate the generated *** this study,the impact of wind energy on the small-signal stability of the power system is *** combinations of AVR and PSS types are considered to mitigate the undesirable alterations.A comparative study is performed based on numerical simulations to choose the best combination of AVR and PSS *** obtained results prove that the proposed combination yields good results in terms of stability enhancement both under normal operating conditions and in DFIG-based wind farms.

关键词： Power system stability Power transmission system Transient analysis Voltage regulation

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Neurogenesis dynamics in the olfactory bulb:deciphering circuitry organization, function, and adaptive plasticity

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Neural Regeneration Research 2025年第6期20卷 1565-1581页

作者： moawiah m.Naffaa Department of Psychology and Neuroscience Duke UniversityDurhamNCUSA Department of Cell Biology Duke University School of MedicineDurhamNCUSA

Adult neurogenesis persists after birth in the subventricular zone, with new neurons migrating to the granule cell layer and glomerular layers of the olfactory bulb, where they integrate into existing circuitry as inhibitory interneurons. The generation of these new neurons in the olfactory bulb supports both structural and functional plasticity, aiding in circuit remodeling triggered by memory and learning processes. However, the presence of these neurons, coupled with the cellular diversity within the olfactory bulb, presents an ongoing challenge in understanding its network organization and function. moreover,the continuous integration of new neurons in the olfactory bulb plays a pivotal role in regulating olfactory information processing. This adaptive process responds to changes in epithelial composition and contributes to the formation of olfactory memories by modulating cellular connectivity within the olfactory bulb and interacting intricately with higher-order brain regions. The role of adult neurogenesis in olfactory bulb functions remains a topic of debate. Nevertheless, the functionality of the olfactory bulb is intricately linked to the organization of granule cells around mitral and tufted cells. This organizational pattern significantly impacts output, network behavior, and synaptic plasticity, which are crucial for olfactory perception and memory. Additionally, this organization is further shaped by axon terminals originating from cortical and subcortical regions. Despite the crucial role of olfactory bulb in brain functions and behaviors related to olfaction, these complex and highly interconnected processes have not been comprehensively studied as a whole. Therefore, this manuscript aims to discuss our current understanding and explore how neural plasticity and olfactory neurogenesis contribute to enhancing the adaptability of the olfactory system. These mechanisms are thought to support olfactory learning and memory, potentially through increased

关键词： network adaptability neurogenesis neuronal communication olfactory bulb olfactory learning olfactory memory synaptic plasticity

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mitochondria–cGAS–STING axis is a potential therapeutic target for senescence-dependent inflammaging-associated neurodegeneration

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Neural Regeneration Research 2025年第3期20卷 805-807页

作者： Josém.Izquierdo Centro de Biología molecular Severo Ochoa(CBm) Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid(CSIC-UAM)MadridSpain

The word “senescence” comes from the Latin senescens, meaning “to begin to age”, and is characterized by a long-lasting but reversible block in proliferation, resulting from stress-induced cell cycle arrest of pre... 详细信息

关键词： Latin potential lasting

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Enhancing Thermal Performance of a Parabolic Trough Collector with Inserting Longitudinal Fins in the Down Half of the Receiver Tube

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Journal of Thermal Science 2020年第5期29卷 1309-1321页

作者： LAARABA adel mEBARKI Ghazali Department of physics University of BatnalBatna 05000Algeria Faculty of Technology LESEI LaboratoryDepartment of Mechanical EngineeringUniversity of Batna2Batna 05000Algeria

Heat transfer in a finned absorber of a parabolic trough collector was studied numerically. The main aim of this work was to study the effect of attached fins on the enhancement of the thermal performance of a parabolic trough collector. The values of the fin's length varied from 0 to 20 mm;their thicknesses varied from 0 to 8 mm and their number was 5. The parameters used in the current study are: the thermal and dynamic field,friction coefficient, Nusselt number, the thermal efficiency and thermal enhancement index. Obtained results show that inclusion of fins to the lower half of the absorber tube can enhance the heat transfer between the absorber tube and working fluid. The increase of the fin*s length increases the friction factor, Nusselt number and thermal efficiency, and the increase of fin's thickness also increases the previous parameters. Starting the value 6 mm of thickness, its effect remains the same, but thickness is less effective than length. The values 15 mm of length and 6 mm of thickness are selected as optimal values. Results show that the inclusion of the fins enhances the thermal performance of the parabolic collector by 8.45%.

关键词： solar energy Nusselt number thermal efficiency parabolic trough collector forced convection

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