Safe Conditions for Conducting Tests Using Ballistic Facilities

2019 ◽  
pp. 105-114
Author(s):  
S.I. Gerasimov ◽  
I.A. Odzeriho ◽  
R.V. Gerasimova ◽  
A.V. Salnikov ◽  
A.P. Kalmykov ◽  
...  
Keyword(s):  
High Speed ◽  
Practical Implication ◽  
Structure Change ◽  
Heating Rates ◽  
Significant Challenge ◽  
Modern Engineering ◽  
High Heating ◽  
Compressed Gas ◽  
Strong Compression ◽  
Exterior Ballistics

Understanding the physical and thermomechanical response of materials subjected to intense dynamic loading is a significant challenge that has a practical implication for modern engineering. Shock compression followed by expansion precipitates both reversible and irreversible physical and mechanical processes in the material. These processes include strong compression in solids, high heating rates, phase transformations, electronic structure change, work hardening, spalling. Methods and devices for producing intense shock loads can be subdivided into several groups. Presently, in worldwide practice, gun type launchers have gained the widest acceptance in studying dynamic compressibility, strength characteristics, and spallatation phenomena in laboratory conditions. In this type of facility, the launched body moves in a tube under the force of a compressed gas. The facilities differ depending on the gas used and the method of its compression. Specific features of the facilities impose certain limitations on the registration and format of the tests. Examples of determining the boundary between the interior and exterior ballistics, the influence of the launched body supporting elements and the conditions of safe testing at high-speed entry in fuel are considered in this work.

Study of dynamic features of highly energetic reactions by DSC and High-Speed Temperature Scanner (HSTS)

2013 ◽  
Vol 1521 ◽  
Author(s):  
M.A. Hobosyan ◽  
Kh.G. Kirakosyan ◽  
S.L. Kharatyan ◽  
K.S. Martirosyan
Keyword(s):  
High Speed ◽  
Initial Period ◽  
Exothermic Reaction ◽  
Dynamic Features ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Dsc Measurements ◽  
High Heating ◽  
Mechanism And Kinetics ◽  
Conventional Dsc

ABSTRACTThe dynamic features of Al2O3 - polytetrafluoroethylene (PTFE) and Al - PTFE reactions in non-isothermal conditions are presented. The Differential Scanning Calorimetry (DSC) and High-Speed Temperature Scanner (HSTS) were used to characterize the Al2O3/Al – PTFE reactions at different heating rates. The study shows that the HSTS instrument can give more information about the reaction mechanism and kinetics than the conventional DSC measurements. In this work we show that high heating rates may reveal exothermic reaction between Al2O3 and PTFE that were previously unidentified. The PTFE can potentially remove the oxide layer from aluminum in the initial period of the reaction and increase the direct contact area between oxygen and aluminum, which increases the reaction velocity and improves the energy release abilities of the system.

scholarly journals Joint Reduction of NiO/WO3 Pair and NiWO4 by Mg + C Combined Reducer at High Heating Rates

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1351
Author(s):  
Marieta Zakaryan ◽  
Khachik Nazaretyan ◽  
Sofiya Aydinyan ◽  
Suren Kharatyan
Keyword(s):  
Composite Materials ◽  
High Speed ◽  
Synergetic Effect ◽  
Isoconversional Method ◽  
Heating Rates ◽  
Formation Pathway ◽  
High Heating ◽  
Functional Features ◽  
Maximum Temperatures ◽  
Solid Liquid

Functional features of Ni-W composite materials combined with successful performance enabled a breakthrough in their broad application. To disclose the formation pathway of Ni-W composite materials at extreme conditions of combustion synthesis in the NiO-WO3-Mg-C and NiWO4-Mg-C systems for the optimization of the synthesis procedure, the process was modeled under programmed linear heating conditions by thermal analysis methods. The reduction kinetics of tungsten and nickel oxides mixture and nickel tungstate by Mg + C combined reducer at non-isothermal conditions was studied at high heating rates (100–1200 °C min−1) by high-speed temperature scanner techniques. It was shown that when moving from low heating to high heating rates, the mechanism of both the magnesiothermic and magnesio-carbothermic reductions of the initial mixtures changes; that is, the transition from a solid-solid scheme to a solid-liquid scheme is observed. The strong influence of the heating rate on the reduction degree and kinetic parameters of the systems under study was affirmed. The simultaneous utilization of magnesium and carbon as reducers allowed the lowering of the starting and maximum temperatures of reduction processes, as evidenced by the synergetic effect at the utilization of a combined reducer. The effective values of activation energy (Ea) for the reactions proceeding in the mixtures NiO + WO3 + 4Mg, NiO + WO3 + 2.5Mg + 1.5C, NiWO4 + 4Mg and NiWO4 + 2Mg + 2C were estimated by Kissinger isoconversional method and were 146 ± 10, 141 ± 10, 216 ± 15 and 148 ± 15 kJ mol−1, respectively.

Comparing fast inductive tempering and conventional tempering: Effects on microstructure and mechanical properties

2018 ◽  
Vol 115 (4) ◽  
pp. 407 ◽  
Author(s):  
Annika Eggbauer Vieweg ◽  
Gerald Ressel ◽  
Peter Raninger ◽  
Petri Prevedel ◽  
Stefan Marsoner ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Energy ◽  
Charpy Impact ◽  
Heat Treating ◽  
Processing Route ◽  
High Heating Rate ◽  
Heating Rates ◽  
High Heating ◽  
Tempering Treatment ◽  
Carbide Distribution

Induction heating processes are of rising interest within the heat treating industry. Using inductive tempering, a lot of production time can be saved compared to a conventional tempering treatment. However, it is not completely understood how fast inductive processes influence the quenched and tempered microstructure and the corresponding mechanical properties. The aim of this work is to highlight differences between inductive and conventional tempering processes and to suggest a possible processing route which results in optimized microstructures, as well as desirable mechanical properties. Therefore, the present work evaluates the influencing factors of high heating rates to tempering temperatures on the microstructure as well as hardness and Charpy impact energy. To this end, after quenching a 50CrMo4 steel three different induction tempering processes are carried out and the resulting properties are subsequently compared to a conventional tempering process. The results indicate that notch impact energy raises with increasing heating rates to tempering when realizing the same hardness of the samples. The positive effect of high heating rate on toughness is traced back to smaller carbide sizes, as well as smaller carbide spacing and more uniform carbide distribution over the sample.

Effect of low and high heating rates on reaction path of Ni(V)/Al multilayer

2017 ◽  
Vol 193 ◽  
pp. 244-252 ◽  
Author(s):  
Łukasz Maj ◽  
Jerzy Morgiel ◽  
Maciej Szlezynger ◽  
Piotr Bała ◽  
Grzegorz Cios
Keyword(s):  
Reaction Path ◽  
Heating Rates ◽  
High Heating

A FUNDAMENTAL STUDY ON THE COMBUSTION CHARACTERISTICS OF MUNICIPAL WASTE PLASTICS UNDER HIGH HEATING RATES

1995 ◽  
Author(s):  
Θωμαή Παναγιώτου
Keyword(s):  
Combustion Characteristics ◽  
Municipal Waste ◽  
Waste Plastics ◽  
Heating Rates ◽  
Fundamental Study ◽  
High Heating

ΑΥΤΗ Η ΕΡΓΑΣΙΑ ΕΙΝΑΙ ΜΙΑ ΒΑΣΙΚΗ ΕΡΕΥΝΑ ΕΠΑΝΩ ΣΤΗΝ ΚΑΥΣΗ ΠΛΑΣΤΙΚΩΝ ΠΟΥ ΒΡΙΣΚΟΝΤΑΙ ΣΤΑ ΑΠΟΡΡΙΜΑΤΑ (ΠΟΛΥ-ΣΤΥΡΕΝΙΟ (PS), ΠΟΛΥ-ΕΘΥΛΕΝΙΟ (ΡΕ) ΚΑΙ PVC). ΣΦΑΙΡΙΚΑ ΣΩΜΑΤΙΔΙΑ ΠΛΑΣΤΙΚΩΝ ΙΣΟΥ ΜΕΓΕΘΟΥΣ ΔΗΜΙΟΥΡΓΗΘΗΚΑΝ ΣΤΟ ΕΡΓΑΣΤΗΡΙΟ ΚΑΙ ΚΑΗΚΑΝ ΕΝΑ, ΕΝΑ ΣΕ ΗΛΕΚΤΡΙΚΟ ΦΟΥΡΝΟ ΚΑΙ ΘΕΡΜΟΚΡΑΣΙΕΣ 1040 -1400 Κ. Η ΚΑΥΣΗ ΤΩΝ ΣΩΜΑΤΙΔΙΩΝ ΜΕΛΕΤΗΘΗΚΕ ΜΕ ΕΝΑ ΤΡΙΧΡΩΜΑΤΙΚΟ ΠΥΡΟΜΕΤΡΟ ΚΑΙ ΜΙΑ ΥΨΗΛΗΣ ΤΑΧΗΤΗΤΑΣ ΚΙΝΗΜΑΤΟΓΡΑΦΙΚΗ ΜΗΧΑΝΗ, ΩΣΤΕ ΝΑ ΣΥΛΛΕΧΘΟΥΝ ΟΙ ΕΞΗΣ ΠΛΗΡΟΦΟΡΙΕΣ: Α) Ο ΧΡΟΝΟΣ ΤΗΣ ΚΑΥΣΗΣ, Β) ΤΟ ΕΙΔΟΣ ΤΗΣ ΚΑΥΣΗΣ (ΟΜΟΙΟΓΕΝΗΣ Η ΕΤΕΡΟΓΕΝΗΣ), Γ) ΤΟ ΠΑΧΟΣ ΤΗΣ ΦΛΟΓΑΣ ΚΑΙ Δ) Η ΤΑΧΥΤΗΤΑ ΠΤΩΣΗΣ ΤΩΝ ΣΩΜΑΤΙΔΙΩΝ. ΟΙ ΠΛΗΡΟΦΟΡΙΕΣ ΑΥΤΕΣ ΧΡΗΣΙΜΟΠΟΙΗΘΗΚΑΝ ΓΙΑ ΤΟΝ ΥΠΟΛΟΓΙΣΜΟ ΤΗΣ ΣΤΙΓΜΙΑΙΑΣ ΠΕΡΙΕΚΤΙΚΟΤΗΤΑΣ ΤΗΣ ΦΛΟΓΑΣ ΣΕ ΑΙΘΑΛΗ ΚΑΙ ΤΗΣ ΠΡΩΤΕΥΟΥΣΑΣ ΦΥΣΙΚΗΣ ΚΑΙ ΧΗΜΙΚΗΣ ΔΙΕΡΓΑΣΙΑΣ ΚΑΤΑ ΤΗΝ ΚΑΥΣΗ ΤΩΝ ΣΩΜΑΤΙΔΙΩΝ. ΚΑΘΕ ΥΛΙΚΟ ΠΑΡΟΥΣΙΑΣΕ ΜΟΝΑΔΙΚΑ ΧΑΡΑΚΤΗΡΙΣΤΙΚΑ ΚΑΥΣΗΣ. ΟΙ ΦΛΟΓΕΣ ΤΩΝ PVC ΣΩΜΑΤΙΔΙΩΝ ΕΙΧΑΝ ΤΗΝ ΜΕΓΑΛΥΤΕΡΗ ΠΕΡΙΕΚΤΙΚΟΤΗΤΑ ΣΕ ΑΙΘΑΛΗ, ΕΝΩ ΤΩΝ ΡΕ ΤΗΝ ΜΙΚΡΟΤΕΡΗ. Η ΤΑΧΥΤΗΤΑ ΚΑΥΣΗΣ ΤΩΝ PS ΣΩΜΑΤΙΔΙΩΝ ΒΡΕΘΗΚΕ ΟΤΙ ΕΞΑΡΤΑΤΑΙ ΑΠΟ ΤΗΝ ΤΑΧΥΤΗΤΑ ΔΙΑΧΥΣΗΣ ΣΤΗΝ ΑΕΡΙΑ ΦΑΣΗ, ΕΝΩ ΤΩΝ ΡΕ ΑΠΟ ΤΗΝ ΤΑΧΥΤΗΤΑ ΠΥΡΟΛΥΣΗΣ ΤΩΝ ΣΩΜΑΤΙΔΙΩΝ. Η ΑΝΑΦΛΕΞΗ ΤΩΝ PVC ΣΩΜΑΤΙΔΙΩΝ ΕΜΠΟΔΙΣΤΗΚΕ ΑΠΟ ΤΗΝ ΥΠΑΡΞΗ ΤΗΣ ΧΛΩΡΙΝΗΣ ΠΟΥ ΔΙΕΦΥΓΕ ΑΡΧΙΚΑ. ΟΤΑΝ Η ΚΑΥΣΗ ΑΡΧΙΣΕ, ΔΗΜΙΟΥΡΓΗΘΗΚΕ ΜΙΑ ΠΑΧΙΑ ΚΑΙ ΠΡΟΑΝΑΜΙΓΜΕΝΗ ΦΛΟΓΑ ΓΥΡΩΑΠΟ ΤΟ ΣΩΜΑΤΙΔΙΟ.

PTFE–Al2O3 reactive interaction at high heating rates

2014 ◽  
Vol 119 (1) ◽  
pp. 245-251 ◽  
Author(s):  
M. A. Hobosyan ◽  
Kh. G. Kirakosyan ◽  
S. L. Kharatyan ◽  
K. S. Martirosyan
Keyword(s):  
Heating Rates ◽  
High Heating ◽  
Reactive Interaction

Cutting Experiments in Cutting Speeds of up to 200 m/s with a High-Speed Impact Cutting Tester

2012 ◽  
Vol 523-524 ◽  
pp. 1041-1046 ◽  
Author(s):  
Tappei Higashi ◽  
Masato Sando ◽  
Jun Shinozuka
Keyword(s):  
High Speed ◽  
Ambient Pressure ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
High Speed Impact ◽  
Air Gun ◽  
Impact Cutting ◽  
Compressed Gas ◽  
Cutting Experiments ◽  
Cutting Speeds

High-speed orthogonal cutting experiments with cutting speeds of up to 200 m/s with a high-speed impact cutting tester of air-gun type are attempted. In this tester, a light projectile with a small built-in cutting tool is loaded into a tube, being accelerated by a compressed gas. The projectile captures the chip that is indispensable to analyze the cutting mechanism. The projectile holding the chip is decelerated by another compressed gas just after finishing the cutting, being stopped without damage in the tube. Successful experiment can be accomplished by setting adequate values of the operation parameters for the experiment, which are the pressure of each gas and the opening and shutting time of the solenoid-controlled valve for each compressed gas. In order to determine the adequate values of these parameters, a ballistic simulator that simulates the velocity and position of the projectile traveling in the tube is developed. By setting the values of these parameters obtained by the simulator, the cutting speed of 200 m/s is achieved when the ambient pressure is set to be a vacuum and helium is used for each compressed gas. This paper describes the ballistic simulator developed and shows the experimental results of the high-speed cutting of aluminum alloy A2017.

Evolution of Gases from the Pyrolysis of Raw and Torrefied Biomass and from the Oxy-combustion of their Bio-Chars

2021 ◽  
pp. 1-30
Author(s):  
Xiaoxiao Meng ◽  
Wei Zhou ◽  
Emad Rokni ◽  
Xigang Yang ◽  
Yiannis Levendis
Keyword(s):  
Co2 Emissions ◽  
Carbon Capture ◽  
Heating Rates ◽  
Renewable Biomass ◽  
Carbon Capture And Utilization ◽  
Combustion Emissions ◽  
Torrefied Biomass ◽  
High Heating ◽  
Pyrolysis Of Biomass ◽  
N Compounds

Abstract The current research assessed the evolution of gases from pyrolysis of biomass and from subsequent combustion of bio-chars. Raw and torrefied biomass was pyrolyzed in nitrogen or carbon dioxide under high heating rates (104 K/s) and high temperatures (1450 K). Pyrolyzates gases were monitored for carbon, nitrogen and sulfur oxides. Subsequently, generated bio-chars were burned in both conventional (air) and simulated oxy-combustion (O2/CO2) gases. In principle, oxy-combustion of renewable biomass coupled with carbon capture and utilization/sequestration can help remove atmospheric CO2. Pyrolysis of biomass in CO2 generated lower char yields, lower SO2 and NO, and higher CO2, CO and HCN mole fractions, compared to pyrolysis in N2. HCN was the most prominent among all measured nitrogen-bearing gases (HCN, NH3, NO) from biomass pyrolysis. Compared to their combustion in air, bio-chars burned more effectively in 30%O2/79%CO2 and less effectively in 21%O2/79%CO2. Emissions of CO were the lowest in 21%O2/79%CO2. Emissions of HCN were the highest in air combustion, and decreased with increasing O2 mole fraction in oxy-combustion; emissions of NO were highest in 30%O2/79%CO2, and emissions of NO were dominant during bio-char oxy-combustion compared with other N-compounds. In oxy-combustion bio-chars released the lowest emissions of SO2. Finally, the emissions of CO, NO, HCN, and SO2 from combustion of DDGS bio-chars were higher than those from RH bio-chars, because of different physicochemical properties.

High Productivity Thermo-Compression Flip Chip Bonding

2014 ◽  
Vol 2014 (1) ◽  
pp. 000100-000106
Author(s):  
Tom Colosimo ◽  
Horst Clauberg ◽  
Evan Galipeau ◽  
Matthew B. Wasserman ◽  
Michael Schmidt-Lange ◽  
...  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Flip Chip ◽  
Solder Joints ◽  
Rapid Heating ◽  
Temperature Cycle ◽  
Temperature Uniformity ◽  
Heating Rates ◽  
Heating And Cooling ◽  
Chip Technology

Advancements in electronic packaging performance and cost have historically been driven by higher integration primarily provided by fab shrinks that has followed the well-known Moore's law. However, due to the tremendous and continuously increasing cost of building new fabs, the performance/cost improvements achieved via node shrinks are negated. This leaves packaging innovation as the vehicle to achieve future cost-performance improvements. This has initiated a More-than-Moore idea that has led to vigorous R&D in packaging. Advanced packages which employ ultra-fine pitch flip chip technology for chip-to-substrate, chip-to-chip, or chip-to-interposer for the first level interconnect have been developed as an answer to obtaining higher performance. However, the costs are too high as compared to traditional wire bonding. The status today is that the fundamental technical hurdles of manufacturing the new advanced packages have been solved, but cost reduction and yield improvements have to be addressed for large-scale adoption into high volume manufacturing. In traditional flip chip assembly silicon chips are tacked onto a substrate and then the solder joints are melted and mass reflowed in an oven. This mass reflow technique is troublesome as the pitch of the solder bumps become finer. This is due to the large differences in the thermal expansion coefficient of the die and the substrate, which creates stress at the solder joints and warpage of the package when the die and substrate are heated and cooled together. To mitigate and resolve this issue, thermo-compression bonders have been developed which locally reflow the solder without subjecting the entire substrate to the heating and cooling cycle. This requires that the bondhead undergo heating past the melting point of solder and then cooling down to a low enough temperature to pick the next die from the wafer that is mounted to tape. Machines in the market today can accomplish this temperature cycle in 7 to 15 seconds. This is substantially slower than the standard flip chip process which leads to high cost and is delaying the introduction of these new packages. This paper shows a flip chip bonder with a new heating and cooling concept that will radically improve the productivity of thermo-compression bonding. Data and productivity cycles from this new bond head with heating rates of over 200°C/sec and cooling of faster than 100°C/sec are revealed. Experimental results are shown of exceptional temperature accuracy across the die of 5°C throughout the cycle and better than 3°C at the final heating stage. The high speed thermo-compression bonds are analyzed and the efficacy of the new concept is proven. Excellent temperature uniformity while heating rapidly is an absolute necessity for enabling good solder joints in a fast process. Without good temperature uniformity, additional dwell times need to be incorporated to allow heat to flow to all of the joints, negating any benefits from rapid heating. Whereas the current state-of-that-art is often to program temperature in steps, this bonder can be commanded and accurately follows more complex temperature profiles with great accuracy. Examples of how this profiling can be used to enhance the uniformity and integrity of the joints with non-conductive pastes, film, and without underfill along with the associated productivity improvements will be shown. Tests that show portability across platforms that will lead to set up time and yield improvements and are identified and quantified. Additionally new ideas for materials and equipment development to further enhance productivity and yield are explored.

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