ALLOWANCE FOR THE EFFECT OF CONDENSED PARTICLES ON BALLISTIC PARAMETERS OF A SHOT

2021 ◽  
pp. 50-59
Author(s):  
V.A. Burakov ◽  
◽  
A.S. D'yachkovskiy ◽  
A.N. Ishchenko ◽  
V.Z. Kasimov ◽  
...  
Keyword(s):  
Energy Exchange ◽  
Equations Of State ◽  
Burning Velocity ◽  
Combustion Products ◽  
Condensed Phases ◽  
Layer By Layer ◽  
Energy Characteristics ◽  
Wide Range ◽  
Powder Particles ◽  
Propellant Charge

A mathematical model of the shot fired from a powder propellant setup is developed. An arbitrary number of powder particles of various types are supposed to be in a propellant charge, which are different in size, shape, energy characteristics, and layer-by-layer burning velocity. The products of their combustion represent a mixture of non-viscous non-heat conductive gases with known equations of state. These gases are generated during combustion of the powder particle of a corresponding type. Some condensed particles may occur in the mixture of combustion products during the burning of powder particles. The motion of the polydispersed mixture of combustion products along a varying-cross-section channel is described by the laws of conservation of mass, momentum, and energy. When formulating these laws, the mass, momentum, and energy exchange between gas and condensed phases is taken into account. The formulation is universal and allows one to use the laws for modelling a wide range of internal ballistic phenomena. In this paper, a theoretical parametric research is shown as an example, which is aimed at estimating the effect of quantity of the occurring condensed particles on basic ballistic characteristics of a shot.

Compact back-scattered electrons' energy analyzer for standard SEM

1994 ◽  
Vol 52 ◽  
pp. 488-489
Author(s):  
S. Likharev ◽  
A. Kramarenko ◽  
V. Vybornov
Keyword(s):  
Depth Resolution ◽  
High Energy ◽  
Primary Beam ◽  
Layer By Layer ◽  
Energy Analyzer ◽  
High Energy Part ◽  
Small Window ◽  
Energy Part ◽  
Wide Range ◽  
High Voltage Supply

At present time the interest is growing considerably for theoretical and experimental analysis of back-scattered electrons (BSE) energy spectra. It was discovered that a special angle and energy nitration of BSE flow could be used for increasing a spatial resolution of BSE mode, sample topography investigations and for layer-by layer visualizing of a depth structure. In the last case it was shown theoretically that in order to obtain suitable depth resolution it is necessary to select a part of BSE flow with the directions of velocities close to inverse to the primary beam and energies within a small window in the high-energy part of the whole spectrum.A wide range of such devices has been developed earlier, but all of them have considerable demerit: they can hardly be used with a standard SEM due to the necessity of sufficient SEM modifications like installation of large accessories in or out SEM chamber, mounting of specialized detector systems, input wires for high voltage supply, screening a primary beam from additional electromagnetic field, etc. In this report we present a new scheme of a compact BSE energy analyzer that is free of imperfections mentioned above.

Wide-range equations of state for organic liquids

2007 ◽  
Vol 5 ◽  
pp. 113-120 ◽  
Author(s):  
R.Kh. Bolotnova
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
Organic Liquids ◽  
Liquid Phases ◽  
Wide Range ◽  
High Pressures And Temperatures

The method of construction the wide-range equations of state for organic liquids, describing the gas and liquid phases including dissociation and ionization which occurs during an intense collapse of steam bubbles and accompanied by ultra-high pressures and temperatures, is proposed.

Reaction Model Development of Selected Aromatics as Relevant Molecules of a Kerosene Surrogate – The Importance of M-Xylene Within the Combustion of 1,3,5-Trimethylbenzene

2021 ◽  
Author(s):  
Astrid Ramirez Hernandez ◽  
Trupti Kathrotia ◽  
Torsten Methling ◽  
Marina Braun-Unkhoff ◽  
Uwe Riedel
Keyword(s):  
Atmospheric Pressure ◽  
Burning Velocity ◽  
Model Development ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Reaction Model ◽  
Pollutant Emissions ◽  
Similar Species ◽  
Ignition Delay Times ◽  
Wide Range

Abstract The development of advanced reaction models to predict pollutant emissions in aero-engine combustors usually relies on surrogate formulations of a specific jet fuel for mimicking its chemical composition. 1,3,5-trimethylbenzene is one of the suitable components to represent aromatics species in those surrogates. However, a comprehensive reaction model for 1,3,5-trimethylbenzene combustion requires a mechanism to describe the m-xylene oxidation. In this work, the development of a chemical kinetic mechanism for describing the m-xylene combustion in a wide parameter range (i.e. temperature, pressure, and fuel equivalence ratios) is presented. The m-xylene reaction submodel was developed based on existing reaction mechanisms of similar species such as toluene and reaction pathways adapted from literature. The sub-model was integrated into an existing detailed mechanism that contains the kinetics of a wide range of n-paraffins, iso-paraffins, cyclo-paraffins, and aromatics. Simulation results for m-xylene were validated against experimental data available in literature. Results show that the presented m-xylene mechanism correctly predicts ignition delay times at different pressures and temperatures as well as laminar burning velocities at atmospheric pressure and various fuel equivalence ratios. At high pressure, some deviations of the calculated laminar burning velocity and the measured values are obtained at stoichiometric to rich equivalence ratios. Additionally, the model predicts reasonably well concentration profiles of major and intermediate species at different temperatures and atmospheric pressure.

Effect of Different Heat Treatments on Mechanical Properties of Laser Sintered Additive Manufactured Parts

2017 ◽  
Author(s):  
Sagar Sarkar ◽  
Cheruvu Siva Kumar ◽  
Ashish Kumar Nath
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Yield Strength ◽  
Tensile Strain ◽  
Wear Loss ◽  
Layer By Layer ◽  
Solution Annealing ◽  
Wear Properties ◽  
Sem Images ◽  
Wide Range

One of the most popular additive manufacturing processes is laser based direct metal laser sintering process which enables us to make complex three dimensional parts directly from CAD models. Due to layer by layer formation, parts built in this process tend to be anisotropic in nature. Suitable heat treatment can reduce this anisotropic behaviour by changing the microstructure. Depending upon the applications, a wide range of mechanical properties can be achieved between 482–621° C temperature for precipitation-hardened stainless steels. In the present study effect of different heat treatment processes, namely solution annealing, ageing and overaging, on tensile strength, hardness and wear properties has been studied in detail. Suitable metallurgical and mechanical characterization techniques have been applied wherever required, to support the experimental observations. Results show H900 condition gives highest yield strength and lowest tensile strain at break whereas solution annealing gives lowest yield strength and as-built condition gives highest tensile strain at break. SEM images show that H900 and H1150 condition produces brittle and ductile morphology respectively which in turn gives highest and lowest hardness value respectively.XRD analysis shows presence of austenite phases which can increase hardness at the cost of ductility. Average wear loss for H900 condition is highest whereas it is lowest for solution annealed condition. Further optical and SEM images have been taken to understand the basic wear mechanism involved.

Prediction of CO and NOx Pollutants in a Stratified Bluff Body Burner

2017 ◽  
Author(s):  
Pascal Gruhlke ◽  
Fabian Proch ◽  
Andreas M. Kempf ◽  
Enric Illana Mahiques ◽  
Stefan Dederichs ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Bluff Body ◽  
Combustion Products ◽  
Combustion Model ◽  
Wide Range ◽  
Flame Region ◽  
Numerical Grid ◽  
Nitric Oxide Emissions ◽  
Heavy Duty Gas Turbine

The major exhaust gas pollutants from heavy duty gas turbine engines are CO and NOx. The difficulty of predicting the concentration of these combustion products originates from their wide range of chemical time scales. In this paper, a combustion model that includes the prediction of the carbon monoxide and nitric oxide emissions is tested. Large eddy simulations (LES) are performed using a compressible code (OpenFOAM). A modified flamelet generated manifolds (FGM) approach is applied with a thickened flame approach (ATF) to resolve the flame on the numerical grid, with a flame sensor to ensure that the flame is only thickened in the flame region. For the prediction of the CO and NOx emissions, pollutant species transport equations and a second, CO based, progress variable are introduced for the flame burnout zone to account for slow chemistry effects. For the validation of the models, the Cambridge burner of Sweeney and Hochgreb [1, 2] is employed, as both carbon monoxide and nitric oxide [3] data is available.

scholarly journals Highly sensitive and multiplexed in situ protein profiling with cleavable fluorescent streptavidin

2019 ◽  
Author(s):  
Renjie Liao ◽  
Diego Mastroeni ◽  
Paul D. Coleman ◽  
Jia Guo
Keyword(s):  
Signal Amplification ◽  
Individual Cell ◽  
Protein Detection ◽  
Protein Profiling ◽  
Detection Sensitivity ◽  
Layer By Layer ◽  
Protein Targets ◽  
Highly Sensitive ◽  
Wide Range

AbstractThe ability to perform highly sensitive and multiplexed in situ protein analysis is crucial to advance our understanding of normal physiology and disease pathogenesis. To achieve this goal, here we develop an approach using cleavable biotin conjugated antibodies and cleavable fluorescent streptavidin (CFS). In this approach, protein targets are first recognized by the cleavable biotin labeled antibodies. Subsequently, CFS is applied to stain the protein targets. Though layer-by-layer signal amplification using cleavable biotin conjugated orthogonal antibodies and CSF, the protein detection sensitivity can be enhanced by at least 10 fold, compared with the existing methods. After imaging, the fluorophores and the biotins unbound to streptavidin are removed by chemical cleavage. The leftover streptavidin is blocked by biotin. Upon reiterative analysis cycles, a large number of different proteins with a wide range of expression levels can be unambiguously detected in individual cell in situ.

Optimization of Metallic Powder Filaments for Additive Manufacturing Extrusion (MEX)

2021 ◽  
Author(s):  
Fábio Silva Cerejo ◽  
Daniel Gatões ◽  
Teresa Vieira
Keyword(s):  
Additive Manufacturing ◽  
Low Cost ◽  
Metallic Powder ◽  
Powder Injection ◽  
Layer By Layer ◽  
Powder Injection Moulding ◽  
Powder Particles ◽  
Powder Content ◽  
Metallic Parts ◽  
Am Processes

Abstract Additive manufacturing (AM) of metallic powder particles has been establishing itself as sustainable, whatever the technology selected. Material Extrusion (MEX) integrates the ongoing effort to improve AM sustainability, in which low-cost equipment is associated with a decrease of powder waste during manufacturing. MEX has been gaining increasing interest for building 3D functional/structural metallic parts because it incorporates the consolidated knowledge from powder injection moulding/extrusion feedstocks into the AM scope—filament extrusion layer-by-layer. Moreover, MEX as an indirect process can overcome some of the technical limitations of direct AM processes (laser/electron-beam-based) regarding energy-matter interactions. The present study reveals an optimal methodology to produce MEX filament feedstocks (metallic powder, binder and additives), having in mind to attain the highest metallic powder content. Nevertheless, the main challenges are also to achieve high extrudability and a suitable ratio between stiffness and flexibility. The metallic powder volume content (vol.%) in the feedstocks was evaluated by the critical powder volume concentration (CPVC). Subsequently, the rheology of the feedstocks was established by means of the mixing torque value, which is related to the filament extrudability performance.

Metal-organic framework (MOF) composites for photodegradation of hazardous organic materials

2021 ◽  
Vol 02 ◽  
Author(s):  
Xinxin Liu ◽  
Jiaqing Ren ◽  
Jiaqi Fang ◽  
An Pan ◽  
Nianqiao Qin ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Metal Organic Framework ◽  
Stable Process ◽  
Layer Growth ◽  
Thermal Method ◽  
Layer By Layer ◽  
Wide Range ◽  
Metal Organic ◽  
Organic Framework

: Photocatalytic degradation is an energy-efficient, cost-effective, and stable process that has a wide-range of applications. It is considered a promising method for the removal of organic pollutants. As a new type of porous materials, Metal-organic framework (MOF) composites have been proven to be an ideal catalyst for the degradation of organic pollutants due to their small size and large specific surface area. In this review, several common preparation methods of MOF composites are evaluated：microwave synthesis, solvent-thermal method, electrochemical method and layer by layer growth method. The degradation effects of MOF composites on different organic pollutants are summarized, and the excellent photocatalytic performances of some MOF composites are demonstrated. Finally, the prospect of photocatalytic degradation of organic pollutants by MOF composites is examined, and the challenges of further development of MOF composites are discussed.

Room-Temperature Ceramic Nanocoating Using Nanosheet Deposition Technique

2013 ◽  
Vol 2013 (CICMT) ◽  
pp. 000014-000018 ◽  
Author(s):  
M. Osada ◽  
T. Sasaki
Keyword(s):  
Room Temperature ◽  
Organic Molecules ◽  
Structural Diversity ◽  
Layer By Layer ◽  
Precise Control ◽  
Langmuir Blodgett ◽  
Wide Range ◽  
Potential Applications ◽  
Layer Assembly ◽  
Selection Of

We present a novel procedure for ceramic nanocoating using oxide nanosheet as a building block. A variety of oxide nanosheets (such as Ti1−δO2, MnO2 and perovsites) were synthesized by delaminating appropriate layered precursors into their molecular single sheets. These nanosheets are exceptionally rich in both structural diversity and electronic properties, with potential applications including conductors, semiconductors, insulators, and ferromagnets. Another attractive aspect is that nanosheets can be organized into various nanoarchitectures by applying solution-based synthetic techniques involving electrostatic layer-by-layer assembly and Langmuir-Blodgett deposition. It is even possible to tailor superlattice assemblies, incorporating into the nanosheet galleries with a wide range of materials such as organic molecules, polymers, and inorganic/metal nanoparticles. Sophisticated functionalities or paper-like devices can be designed through the selection of nanosheets and combining materials, and precise control over their arrangement at the molecular scale.

scholarly journals Modeling C540-C20 Fullerene Collisions

2018 ◽  
Vol 57 (2) ◽  
pp. 143-150 ◽  
Author(s):  
Leysan Kh. Rysaeva ◽  
Ivan P. Lobzenko ◽  
Julia A. Baimova ◽  
Sergey V. Dmitriev ◽  
Kun Zhou
Keyword(s):  
Molecular Dynamics ◽  
Energy Exchange ◽  
Translational Motion ◽  
Carbon Clusters ◽  
Chemical Bonds ◽  
Collision Velocity ◽  
C20 Fullerene ◽  
Wide Range ◽  
Pauli Repulsion ◽  
Very High

Abstract Collisions of C20 and C540 fullerenes are studied in a wide range of velocities by means of classical molecular dynamics. The simulations show that the collision scenario strongly depends on the collision velocity of the fullerenes. At low collision energies, the fullerenes are repelled by the van der Waals forces, and after bouncing off a part of the kinetic energy of their translational motion is converted into the energy of cage vibrations. At higher collision energies, the fullerenes overcome the potential barrier of Pauli repulsion with the formation of the new chemical bonds, and a significant change in the geometry of the molecules is observed. At very high collision energies, structure of the molecules is destroyed with the formation of new carbon clusters. Analysis of collisions for fullerenes of significantly different size revealed some new features associated with their asymmetric energy exchange.

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