Theoretical Parameters Research Articles

Computation of Cross-sections by Effects of Theoretical Parameters Code for Production of 52Mn Radioisotope

Abstract: Theoretical calculations focusing on cross-section data results for the production of 52Mn from a natural chromium (natCr) target have been investigated for deuteron beams up to 35 MeV by using the EMPIRE 3.2.2 Malta nuclear model code. The optimization of theoretical calculations is important for the medical production routes of cross-section isotopes. In these computations, we tested different ATILNO parameters for the evaluation of cross-section data and improved techniques for the theoretical calculation of radioisotope 52Mn. The effects of these parameters were investigated, and the theoretical results were subsequently compared with each other, existing literature data, and the TENDL-2019 library. Keywords: EMPIRE code, Cross-section, Manganese-52, Radionuclide production, Positron emission tomography.

A comparison between theoretical results and experimental data of transition probability B(E2), deformation parameter, and intrinsic quadrupole moments for different nuclei with mass number A = 44

A comparison has been made between theoretical results and the experimental data for different nuclei (even-even) that possess the same mass number A = 44 and which have close values of the experimental deformation parameter such as 16S44, 18Ar44, 20Ca44 and 22Ti44. The core-polarization effects and model space were adopted through the inclusion of effective charges. Transition probability B(E2), theoretical deformation parameters, and theoretical intrinsic quadruple moments were calculated using two different interactions for each case, the first case the hasp interaction for nuclei in the sd shell, and the fpd6 interaction for nuclei in the fp shell, the second case the vpnp interaction for nuclei in the sd shell, and the kb3 interaction for nuclei in the fp shell, as well as adopted to different effective charges, such as Bohr and Mottelson effective charges, standard effective charges, and the effective charges from program NuShellX. The theoretical results of the transition probability B(E2), deformations parameters, and intrinsic quadruple moments were compared and found to be close to the experimental values for these nuclei.

Research on dynamic deformation behaviors of laser driving metal sheet precision forming

Laser shock forming (LSF) is an advanced sheet forming technology. With the aid of forming die, it can realize sheet precise forming, and has extensive application prospects in aeronautic and electronics industries. In the paper, a two-dimensional axial symmetric numerical model of SUS304 stainless steel is established. Finite element method is utilized to explore the dynamic deformation behaviors of the laser-driving sheet impacted by the forming die. The results show that the node velocity of metal sheet increases in an oscillatory manner during initial stage and then it starts to bulge. After collision with die cavity bottom, the central region of metal sheet jumps up reversely, and experiences repeating damped vibration. The metal sheet gradually exhausts the obtained kinetic energy from the shock wave, and the flat sheet is finally shaped into the geometrical shape of die cavity. The sheet forming precision can be improved by way of increasing laser shock pressure. The corresponding experiments are also carried out to verify the predicted results. The applied method and gained results can provide a reference for theoretical research and parameters optimization in LSF.

Subsistence via Jala-Samadhi (Sacred Suicide): An Enigmatic Activism of Yogmaya

Collective jal-samadhi (killing oneself by plunging in the river) is one of the rare evidences in the resistance history that Yogmaya led from the Eastern part of Nepal at the verge of Rana regime. This paper examines her three different aspects - her life story, her Sarwartha Yogbani, and her collective jala-samadhi - to argue Yogmaya as an enigmatic social activist. The main purpose is to foreground her life struggle with reference to her Sarwartha Yogbani from the perspective of subaltern studies. The notions of ‘hegemony’ and ‘subaltern’ as Antonio Gramsci and Gayatri Chakravorty Spivak point out when ‘agency’ of the oppressed is concerned have been applied as theoretical parameters to foreground her story. The finding of the study shows subsistence of her resistance via jal-samadhi that helps engage intellectuals in academic activism and critical discourse in the history form below perspective.

Exploring Electronic and Structural Properties of Titanium-Doped Chlorapatite: A Theoretical and Experimental Investigation

The apatite family stands as a pivotal class of inorganic compounds with diverse elemental components, playing a crucial role in biological, environmental, and geological contexts. Among these, chlorapatite (ClAp) emerges as a significant member, featuring a hexagonal structure with the space group P63/m. In this theoretical study, we delve into the unexplored realm of Ti-doped ClAp structures, investigating their electronic and structural characteristics for the first time. Motivated by the potential impact of titanium (Ti) doping on electronic and optical properties, we employ density functional theory (DFT) principles to perform band structure calculations. The electronic band structure is explored comprehensively, shedding light on the energy distribution for electrons as a function of momentum. Our calculations reveal that un-doped ClAp exhibits an insulating nature, as indicated by a calculated band gap of approximately 4.947 eV. The theoretical volume parameter closely matches experimental observations, validating the reliability of our computational model. Introducing Ti as a dopant in 1.2TiClAp results in a discernible increase in the band gap to approximately 5.339 eV. The theoretical volume parameter exhibits excellent agreement with experimental data, emphasizing the precision of our calculations. For 2.4TiClAp, the band gap remains stable at around 5.344 eV, while the theoretical volume parameter stands at 0.5260 nm3. Our systematic exploration of Ti-doped ClAp underscores the tunability of electronic properties, signifying potential applications across diverse fields. The reliability of theoretical calculations is further affirmed by the consistent alignment with experimental parameters. These findings contribute significantly to our fundamental understanding of Ti-doped ClAp, providing crucial insights for material design and optimization. Ongoing collaborative efforts between theoretical and experimental approaches are essential for a comprehensive assessment of these complex materials.

Exploring the Conductivity, Solubility, and thermodynamic properties of sulfonated waste styrofoam through experimental and theoretical studies

In this work, sulfonated WPS (SWPS) was synthesized using concentrated sulfuric acid (Con. H2SO4) at various concentrations (0.01–0.05 mol.dm−3) and temperatures (313 K, 333 K, and 353 K) and the structure was confirmed by various analytical techniques. The degree of sulfonation (DS) values was determined using cation exchange capacity (CEC), 1H NMR, and UV–visible spectroscopy, and to investigate the influence of temperature and various concentration of H2SO4 during the sulfonation reaction. The conductivity of the SWPS was calculated and found to range from 0.23 × 10−6 S.cm−1 to 40.2 × 10−6 S.cm−1. The theoretical solubility parameters of SWPS were determined and compared with experimental values. Using Frenkel-Erying equation, Thermodynamic parameters of SWPS was calculated and also evaluated the correlation between the intrinsic viscosity (η) and viscous flow activation free energy (ΔGv). Our findings contribute to a better understanding of the sulfonation reaction of WPS and the potential applications of SWPS as a functional material.

Two-dimensional Parameter Relationships for W UMa-type Systems Revisited

Reviewing the empirical and theoretical parameter relationships between various parameters is a good way to understand more about contact binary systems. In this investigation, two-dimensional (2D) relationships for P–M V(system), P–L 1,2, M 1,2–L 1,2, and q–L ratio were revisited. The sample used is related to 118 contact binary systems with an orbital period shorter than 0.6 days whose absolute parameters were estimated based on the Gaia Data Release 3 parallax. We reviewed previous studies on 2D relationships and updated six parameter relationships. Therefore, Markov chain Monte Carlo and Machine Learning methods were used, and the outcomes were compared. We selected 22 contact binary systems from eight previous studies for comparison, which had light curve solutions using spectroscopic data. The results show that the systems are in good agreement with the results of this study.

Synthesis, crystal structure, Hirshfeld surface analysis and DFT calculations of novel clusianone analogues as anticancer agents that downregulate β-tubulin and Cdk1/Cyclin B1

Clusianone is a natural product that has been shown to possess anticancer activity, however, studies on its potential anticancer activity remain limited and few. In this study, we further investigated the anticancer potential of clusianone by initially isolating clusianone from Garcinia parvifolia leaves and then using it to synthesise a total of 8 analogues, of which 5 are novel and being reported for the first time. Clusianone and its analogues’ reactivity and chemistry were thoroughly investigated, while the crystal structure of methylated clusianone, compound 1, was obtained and discussed. The crystal structure for 1 was used to conduct Hirshfeld surface analysis whereby it was found that H···H interactions contributed the most to the crystal packing. Moreover, DFT calculations showed that the calculated theoretical parameters for the optimised structure of 1 were in good agreement with the experimental x-ray diffraction measurements. The analogues that were obtained in good yields were further screened against A549 (lung) and HK1 (nasopharyngeal) cancer cells via the MTT assay. Results showed that introduction of an imine (C=N) group to clusianone resulted in bioactive compounds, with the methylamine derivative (compound 4) demonstrating the highest cytotoxic activity followed by clusianone. Further studies on clusianone and 4 showed that they caused apoptosis-related morphological changes in the cancer cells. Furthermore, the compounds were found to inhibit cancer cell division via decreasing the protein expression levels of β-tubulin and Cdk1/Cyclin B1 with 4 demonstrating a more pronounced effect against the proteins than clusianone. DFT calculations on 4 suggested that its high bioactivity could be attributed to its high chemical reactivity due to its lower HOMO-LUMO gap and lower chemical hardness. This study demonstrates the potential of 4 as an effective natural product derived anticancer agent.

Design, Manufacturing, and Testing Process of a Lab Scale Test Bench Hybrid Rocket Engine

The current paper presents the architecture of a test bench for small (laboratory) scale hybrid rocket motors destined for teaching purposes. The sustainability of the proposed methodology is emphasized, as it addresses the development of small-scale hybrid rocket motor test benches, to be used either as didactic means for students or for research laboratories, by using low-cost materials, while preserving efficiency. In this regard, the entire development process is approached, from designing to manufacturing (including the casting of the fuel rod) and testing of the product. The developed product uses a mixture of 88% paraffin, 10% stearic acid, and 2% coal for the solid phase and liquid oxygen for the liquid phase. The testing of the hybrid rocket motor demonstrator was performed outdoors, in controlled conditions. The results showed a good correlation between the theoretical testing parameters with the obtained ones.

Voice of Emancipation from Caste Discrimination: Reading Untouchability and Injustice in Dulal’s Gahugoro Africā

This paper attempts to analyze the issues on the untouchability, injustice and voice declaration of emancipation from caste discrimination in Bishowbhakta Dulal’s Gahugoro Africa. Dalits as Africans are primarily artisans and utilize their skills and perform the imposed duties. However, they get fewer wage and they are hated, humiliated, discriminated, exploited and traumatized in the society by the upper caste people and the nation even in the twenty-first century. Therefore, the purpose of this paper was to analyze the voice of emancipation from various evil cultural practices like caste discrimination, untouchability and injustice. The text was chosen purposively and the research was conducted using a library-based qualitative approach, utilizing relevant texts and sources to analyze the objective. The researcher has implemented cultural studies perspective and the discursive approach of Stuart Hall as main and other theorists’ ideas as supporting tools for theoretical parameters. The data were collected by text information, description and record keeping. The researcher examined that Dalits have been considered untouchable, distanced and humiliated despite their vital role in the society. The imposed professions that were assigned to them could not suffice their needs. Dalits have presented themselves everywhere still they have been the victims of socio-cultural biasness and injustice. So the speaker strictly declares emancipation from every type of cultural shackles. Freedom from such evil practice is inevitable for Dalits in Nepal. So, it is the representative voice of Dalits (Kami, Damai, Sarki, Badi, Gaine, Mushahar and Cyame) in general. The research is significant due to its focus on the inhuman treatment and miserable existence of Dalits in the context of Nepal. The exploration on the voice of emancipation from the caste discrimination in the diverse cultures and cultural practices is valuable to academia.

Re-utilization of long lived 99Tc radio isotope via Photon induced nuclear reactions

Technetium-99 is a radioactive waste produced primarily in nuclear reactors. It is also left as radioactive waste in hospitals, directly from 99mTc isomeric state. To bring down the quantity of technetium-99 radioactive waste, the nuclear reactions using photon beam is explored. The integral cross section of the reaction 99Tc(γ,γ′)99mTc has been determined using the photo-nuclear activation method. The experiment was done using bremsstrahlung photons having endpoint energies viz. 6, 9, 12, 16, and 20 MeV. 115In(γ,γ′)115mIn reaction has been used as a monitor reaction, for the flux normalization of the bremsstrahlung spectrum. Theoretical model calculations have been done using the nuclear reaction code Talys 1.9. Theoretical parameter values are optimized with the presently obtained data. Total cross sections are estimated and investigated the feasibility of re-utilization of the technetium-99 radioactive isotope.

An Effective, Green Synthesis Procedure for Obtaining Coumarin-Hydroxybenzohydrazide Derivatives and Assessment of Their Antioxidant Activity and Redox Status.

In this study, green synthesis of two derivatives of coumarin-hydroxybenzohydrazide, (E)-2,4-dioxo-3-(1-(2-(2,3,4-trihydroxybenzoyl)hydrazyl)ethylidene)-chroman-7-yl acetate (C-HB1), and (E)-2,4-dioxo-3-(1-(2-(3,4,5-trihydroxybenzoyl)hydrazyl)ethylidene)chroman-7-yl acetate (C-HB2) is reported. Using vinegar and ethanol as a catalyst and solvent, the reactions were carried out between 3-acetyl-4-hydroxy-coumarin acetate and corresponding trihydroxybenzoyl hydrazide. The antioxidant potential of these compounds was investigated using the DPPH and ABTS assays, as well as the FRAP test. The obtained results reveal that even at very low concentrations, these compounds show excellent radical scavenging potential. The IC50 values for C-HB1 and C-HB2 in relation to the DPPH radical are 6.4 and 2.5 μM, respectively, while they are 4.5 and 2.0 μM in relation to the ABTS radical. These compounds have antioxidant activity that is comparable to well-known antioxidants such as gallic acid, NDGA, and trolox. These results are in good correlation with theoretical parameters describing these reactions. Moreover, it was found that inhibition of DPPH● follows HAT, while inactivation of ABTS+● follows SET-PT and HAT mechanisms. Additionally, coumarin-hydroxybenzohydrazide derivatives induced moderate cytotoxic activity and show significant potential to modulate redox status in HCT-116 colorectal cancer cells. The cytotoxicity was achieved via their prooxidative activity and ability to induce oxidative stress in cancer cells by increasing O2˙- concentrations, indicated by increased MDA and GSH levels. Thus, ROS manipulation can be a potential target for cancer therapies by coumarins, as cancer cells possess an altered redox balance in comparison to normal cells. According to the ADMET analysis, the compounds investigated show good pharmacokinetic and toxicological profiles similar to vitamin C and gallic acid, which makes them good candidates for application in various fields of industry and medicine.

Elucidating the corrosion inhibition mechanisms: A computational and statistical exploration of the molecular structure-efficiency relationship for phenolic Schiff bases in acidic medium on the mild steel surface

This study investigated mild steel corrosion inhibition using four Schiff bases in a theoretical framework. The study used statistical analysis to relate the experimental inhibitor's efficacy to theoretical data, revealing the corrosion inhibition process. Density functional theory (DFT) was used to assess the global reactivity of the four inhibitors' neutral, protonated, and complex forms. Where, Fukui functions were used for local reactivity study of the four inhibitors in neutral and protonated forms. To study system dynamics at the inhibitor-steel contact, a Monte Carlo simulation was performed. The experimental and quantum results are strongly correlated when the global quantum features of the neutral and protonated forms, such as the dipole moment μ, EHOMO, and ELUMO, are examined. The PA and pKa protonation parameters demonstrate that the protonation of the compounds strongly influences the inhibition efficiency. According to Fukui functions, the amine function (N) is the highest nucleophilic reactivity, making it highly sensitive to electrophilic attack, for all four inhibitors. The stability and predominance of complex forms in the medium were interpreted using thermodynamic characteristics of PSBi-FeCl2 complexes. Monte Carlo simulation yielded the most stable adsorption configurations, which were geometrically and energetically examined to explain experimental data. QSAR shows a significant linearity between theoretical parameters and experimental inhibitory efficiency.

CN and CCH azirine derivatives, possible precursors of prebiotic molecules: formation and spectroscopic parameters

ABSTRACT N-heterocycles are of special relevance in astrobiology but at present no nitrogen-containing heterocycles have been detected in the interstellar medium (ISM). Thus far, the simplest N-heterocyclic compound, 2H-Azirine (c-C2H3N), has not been conclusively identified, despite being searched for. Recently, several cyano and ethynyl derivatives of unsaturated hydrocarbons have been discovered in the cold prestellar core Taurus Molecular Cloud 1 (TMC-1). The purpose of this work is to assess the feasibility of the possible formation of cyano and ethynyl derivatives of azirine (c-C2H2N-CN, c-C2H2N-CCH) under interstellar conditions and provide high-level theoretical spectroscopic parameters of the most relevant cyano- and ethynyl-azirine isomers to facilitate their experimental identification. Six isomers are located for each, cyano- and ethynyl-azirine derivatives, and their interconversion processes are studied. The reactions of 2H-azirine with the CN or CCH radicals in the gas phase are explored as possible formation routes of cyano and ethynyl azirine. We found that the formation processes of the most stable isomers, namely 3-cyano-2H-azirine, 2-cyano-2H-azirine, 3-ethynyl-2H-azirine, and 2-ethynyl-2H-azirine, are exothermic and barrier free. Thus, these compounds stand out as potential targets to be searched for in space. Based on the newly determined rotational spectroscopic parameters, which also account for 14N hyperfine splittings, we compile a line catalogue for each system up to 50 GHz as a preliminary and required step to characterize these molecules experimentally, whether in the laboratory or directly in the ISM.

Effect of the chain length of geraniol esters on the plasticization efficiency with poly(lactide)

This work reports on the development of environmentally friendly PLA formulations utilizing different esters derived from geraniol as plasticizers. Geranyl formate, acetate, propionate, butyrate, isovalerate and caproate at 10 wt% were combined with PLA in formulations that were produced through extrusion and injection moulding processes. Theoretical solubility parameter studies predicted good miscibility between PLA and all the plasticizers. This was confirmed by tensile test, which showed elongation at break values between 200 and 300 %, totally in contrast with the 8 % value of neat PLA. Geranyl acetate and geranyl formate exhibited the highest elongation at break behavior. These values of elongation at break were supported by FESEM images, which showed clear signs of plasticization. The plasticization effect was further corroborated by DSC and DMTA analysis, where a clear decrease in the glass transition temperature was observed from a typical value of 60 °C for neat PLA down to 40–50 °C for the plasticized blends. This was related to an enhanced chain mobility of the amorphous regions of PLA. Moreover, the plasticizers slightly increased the water absorption capabilities of PLA, as demonstrated by an increase in the water contact angle and water uptake for 11 weeks.

Accurate Estimation of Some Pharmaceutical Compounds Using HPLC Technology

For the assessment of different chemical components in pharmaceutical and biological samples, High Performance Liquid Chromatography (HPLC) can be defined as a commonly utilized analytical method in pharmaceutical samples. HPLC offers high sensitivity, specificity, and accuracy, making it a preferred method for the analysis of complex samples. In this technique, the sample is prepared by extracting, purifying, and concentrating the target analyte from the matrix. Mobile and stationary phases are after that used in chromatographic separation of the prepared sample. Several detectors, including fluorescence, UV-vis, and mass spectrometry, are used to identify and measure the eluted compounds. HPLC is capable of estimating a wide range of elements, including small molecules, peptides, and proteins, making it an essential tool in pharmaceutical research and development. The theoretical plates, peak tailing, and % assay have not been significantly impacted by the deliberate alterations made to the method. This implies that the existing technique is robust. The low values of LOQ and LOD show how sensitive the suggested approach is. The current research used a standard drug solution with six replicates to examine the system suitability parameters. It was discovered that the computed parameters fell under the acceptable criteria. The theoretical plate count, tailing factor, and HETP parameters are all within acceptable ranges. The results of this work are compared with those of earlier research. Upon analyzing the chart, it can be inferred that the proposed method presents certain benefits. The investigation employed a Kromasil C18 column. The obtained retention time is comparatively lower than that of all other methodologies. The maximum quantifiable threshold is 600 μg/mL, surpassing or equating all of the aforementioned techniques. The duration of the execution is also minimal. Therefore, the author draws the conclusion that the HPLC method proposed exhibits sensitivity and reproducibility in analysis of etodolac and thiocolchicoside in combined tablet dosage form, while also requiring a short analysis time.

Light dark matter axion-wind detection with a static electric field

We explore the axionic dark matter search sensitivity with a narrow-band detection scheme aimed at the axion-photon conversion by a static electric field inside a cylindrical capacitor. An alternating magnetic field signal is induced by effective currents as the axion dark matter wind flows perpendicularly through the electric field. At low axion masses, such as in a KKLT scenario, front-end narrow band filtering is provided by using LC resonance with a high Q factor, which enhances the detectability of the tiny magnetic field signal and leads to thermal noise as the major background that can be reduced under cryogenic conditions. We demonstrate that high gaγ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$g_{a\\gamma }$$\\end{document} sensitivity can be achieved by using a strong electric field E∼\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E\\sim $$\\end{document}MVm-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-1}$$\\end{document}. The QCD axion theoretical parameter space would require a high E∼\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E\\sim $$\\end{document} GVm-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-1}$$\\end{document} field strength. Using the static electric field scheme essentially avoids exposing the sensitive superconducting pickup to an applied laboratory magnetic field.

Evaluating and predicting surfactant-induced hydrophilization of pore channels in membrane distillation

Membrane distillation (MD) processes are susceptible to membrane pore wetting, which compromises the membrane's salt rejection efficiency and deteriorates the quality of the distillate. However, current understanding of the dynamics of membrane wetting remains incomplete, and the conventional indicators used to detect post-wetting, such as conductivity and distillate flux, have limitations.We develop a theoretical model for the wetting front (l) to elucidate the adsorption of surfactant molecules and their role in the hydrophilization of commercial polyvinylidene fluoride (PVDF) membranes under various sodium dodecyl sulfate (SDS) concentrations and different membrane pore sizes. Subsequently, we utilize an in-situ impedance-based monitoring technique to quantitatively track the progression of wetting and validate our model's ability to accurately describe the relationship between the wetting front and the square root of time (l=Kt) to obtain the wetting progression coefficient K within the first 30 min of the slow wetting stage.Hence, K, through the combination of impedance measurement and modelling, offers the advancement of wetting until the critical wetting front is reached. This critical wetting front, located at the half point of the membrane thickness, signifies the occurrence of partial wetting, alerting the need for membrane cleaning to mitigate full wetting before it occurs. Additionally, the potential for membrane recoverability can be assessed by examining the variation of K after cleaning, thereby facilitating the evaluation of the effectiveness of different membrane cleaning strategies. The theoretical model and applicable parameters presented in this study contribute to the understanding and quantification of mechanisms slow wetting in surfactant-induced scenarios and provide a promising method for determining the appropriate membrane for the desired feed and the optimal membrane cleaning strategy for extending the lifespan of membranes.

Study on the Transient Flow Characteristics of a Hump Water Pipeline Based on the Random Distribution of Bubbles

Aiming at establishing the transient flow characteristics of gas–liquid two-phase flow in high-undulation water pipelines, based on the bubble distribution law measured using physical tests, the bubble distribution law function was input into the hump-pipe fluid domain model, and CFD numerical simulation was carried out for different flow rates and different air contents. The CLSVOF two-phase flow model and the RNG k-ε turbulence model were used to analyze the flow pattern evolution and pressure pulsation propagation in the process of gas–liquid two-phase flow through a hump pipe. The results show that the bubble size has a lognormal distribution, the equivalent diameter is between 3 mm and 10 mm, and the evolution of the flow pattern in the hump pipe is complex and violent. In the horizontal pipe section, there are three main flow patterns: bubble flow, wavy flow and segment plug flow. In the vertical pipe, there are two main flow patterns, slug flow and churning flow, and the flow pattern is affected by the flow rate and the air content rate. When air bubbles or air pockets in the pipeline flow through a certain area, this leads to a steep increase and decrease in the pressure pulsation amplitude in the region, and the pressure fluctuation is extremely frequent. Compared with the water flow rate, the air content is the main factor affecting the relative pressure pulsation amplitude under the condition of a 0.15-air content operating mode, which is generally approximately two to six times that of the 0-air content operating mode. The results of the research should facilitate the prediction of stagnant gas pipeline system bursts and water hammer protection, providing a theoretical basis and calculation parameters.

Propulsion theoretical and experimental analysis of composite propellants motors

Rockets have revolutionized space technology and human space exploration. Most rockets and missiles are both propelled by rocket motors that use composite solid propellants. The ICT code and the NSAS CEA code are two programs that can be used to forecast theoretical propulsion parameters for composite solid rocket propellant. Rocket propellant performance is governed by a specific impulse factor, which is calculated theoretical and experiment. In this paper, the theoretical specific impulse for different composite solid propellant formulations at 70 bar combustion pressure and an adapted nozzle (optimum expansion) were calculated by the NASA-CEA code and the ICT code. Meanwhile, a static firing test was performed on a small scale test motor to experimentally determine the actual specific impulse. The objective is to verify theoretical calculations from two codes with experimental data, via the determination of the specific impulse deviation co-efficient.