Estimation of explosion energy based on fragment characteristics

I have developed two-dimensional general relativistic magnetohydrodynamic (GRMHD) code. I have performed numerical simulations of collapsars using these codes and realistic progenitor models. In the GRMHD simulation, it is shown that a jet is launched from the center of the progenitor. We also performed simulations of collapsars with different Kerr parameters a = 0, 0.5, 0.9, 0.95. It is shown that a more rapidly rotating black hole is driving a more energetic jet. No jet is seen for the case of Schwartzschild black hole case, while the total energy of the jet is as large as 1050 erg for a rapidly rotating Kerr black hole case (a = 0.95). In order to explain the high luminosity of a GRB, it is concluded that a rapidly rotating black hole is favored ('faster is better'). We also performed two-dimensional hydrodynamic simulations in the context of collapsar model to investigate the explosive nucleosynthesis happened there. It is found that the amount of 56Ni is very sensitive to the energy deposition rate. This result means that the amount of synthesized 56Ni can be little even if the total explosion energy is as large as 1052 erg. Thus, some GRBs can associate with faint supernovae. Thus we consider it is quite natural to detect no underlying supernova in some X-ray afterglows.

We calculate the evolution of multiple supernova (SN) explosions inside a pre-exiting bubble blown up by winds from massive stars, using one-dimensional hydrodynamic simulations including radiative cooling and thermal conduction effects. First, the development of the wind bubble driven by collective winds from multiple stars during the main sequence is calculated. Then multiple SN explosion is loaded at the center of the bubble and the evolution of the SN remnant is followed for <TEX>$10^6$</TEX> years. We find the size and mass of the SN-driven shell depend on the structure of the pre-existing wind bubble as well as the total SN explosion energy. Most of the explosion energy is lost via radiative cooling, while about 10% remains as kinetic energy and less than 10% as thermal energy of the expanding bubble shell. Thus the photoionization and heating by diffuse radiation emitted by the shock heated gas is the most dominant form of SN feedback into the surrounding interstellar medium.

A variety of overbreak control techniques are used during excavation with the drill and blast system. Tracer blasting is used in Canadian underground mines to minimize blast damage and involves placing a low-strength detonating cord along the length of a blast hole prior to charging with ammonium nitrate-fuel oil (ANFO). The results of tracer blasting are not always consistent and its mechanism is only hazily comprehended. In the absence of a clearly defined mechanism, it is difficult to analyse the results of tracer blasting and to identify the factors responsible for the inconsistency of results. A series of bench blasts and pipe tests were carried out to investigate the mechanism of tracer blasting. The evidence indicated partial deflagration and desensitization of ANFO, thus reducing the total available explosive energy. The rock mass surrounding the traced blasthole experienced a low level of ground vibrations. As a result of the continuous side initiation of ANFO, energy partitioning was more in favour of gas energy. A mechanism of tracer blasting has been proposed and the factors responsible for the inconsistency of the results have been identified in this paper.

This study aimed to identify factors affecting the incidence of chemical accidents in chemical process industries. The present study investigated 840 accidents in 42 chemical process industries over 11 years (2008–2018). Data analysis was conducted using exploratory and confirmatory factor analysis (EFA and CFA) and structural equation modeling (SEM). Data analysis was done using IBM SPSS AMOS v. 22. Moreover, χ2/df, RMSEA, CFI, NFI, and NNFA (TLI) indices were used as model fit indices. The descriptive results showed that 45.3% and 32.14% of the accidents were related to transportation and the release of chemicals, respectively. Factor analysis showed that 6 latent factors and 37 indicator variables affected the accidents. SEM findings showed that latent factors, including individual and occupational training, risk management, and their indicator variables, had indirect effects on the chemical accidents (P &lt; 0.05). In contrast, unsafe conditions and unsafe acts latent factors with their indicator variables had a direct impact on the incidence of chemical accidents (P &lt; 0.05). The findings confirmed that chemical accidents are affected by different causal layers. Using different methods of accident analysis and combining them with scientific and updated techniques of other sciences, that is, mathematics, as well as statistics, can improve accident analysis and controlling methodologies.

The chemical industry oversees the transformation of raw materials into products through unit operations that require appropriate organization to avoid accidents. Hence, it is important to do analyses to identify any possible mistakes, substances involved, or common sources of accidents in the industry to avoid such errors and design better safety measures to create a safer space for the chemical industry, which is hugely important and boasts a worldwide presence. This document presents an analysis of chemical industry‐related accidents in Saudi Arabia, namely fires, explosions, and toxic clouds which occurred in the chemical and petrochemical industries and while transporting hazardous materials in the last 46 years. Three databases—one for each type of accident—were created with information collected from articles, newspapers, videos, and papers. ‘Explosion’, ‘fire’, and ‘toxic clouds’ were the key words used for the research, focusing on accident taking place in Saudi Arabia. Once the information had been collected, the accidents were filtered, checked, and moved to a fourth general database. It is shown that 54.0% of all related accidents were fires, 25.4% toxic clouds, and 20.6% were explosions. The provinces with the most registered accidents were Riyadh (15), Jeddah (10), and Jubail (6).

The need for greater sustainability for the production of fuels and chemicals has spurred significant research to rethink the energy use in the chemical industry, and eventually substitute fossil fuel sources by renewable sources. Nowadays, the chemical industry is responsible for about one third of the total energy used - and the associated CO2 emissions - in the industrial sector. Most of the thermal energy used in the chemical industry is not fully recovered (by process-process stream heat exchange), but removed as low grade waste heat that ends up released into the environment. Moreover, there are certain energy intensive operations such as distillation which alone is responsible for about 40 % of the energy used in the chemical process industry. This paper aims to provide an informative perspective on the energy use in the chemical industry. The scope of this mini-review includes: current energy use, eco-efficiency aspects in chemical process industry, Process Integration for heat recovery, thermal energy upgrade by heat pumps, and advanced distillation technologies (reactive distillation, dividing-wall column, cyclic distillation) that can significantly reduce the energy usage and the carbon footprint of the modern chemical plants. Based on the provided overview, several important new research directions are defined towards rethinking the energy use for a more sustainable chemical industry.

The existence of black holes (BHs) of mass ~ 10^{9} M_sun at z > 6 is a big puzzle in astrophysics because even optimistic estimates of the accretion time are insufficient for stellar mass BHs of ~ 10 M_sun to grow into such supermassive BHs. A resolution of this puzzle might be the direct collapse of supermassive stars with mass M ~ 10^{5} M_sun into massive seed BHs. We find that if a jet is launched from the accretion disk around the central BH, the jet can break out the star because of the structure of the radiation pressure-dominated envelope. Such ultra-long gamma-ray bursts with duration of ~ 10^{4} - 10^{6} s and flux of 10^{-11} - 10^{-8} erg s^{-1} cm^{-2} could be detectable by Swift. We estimate an event rate of < 1yr^{-1}. The total explosion energy is > 10^{55} - 10^{56} erg. The resulting negative feedback delays the growth of the remnant BH by about 70 Myr or evacuates the host galaxy completely.

We present extensive ultraviolet, optical, and near-infrared observations of the Type IIP supernova (SN IIP) 2013ej in the nearby spiral galaxy M74. The multicolor light curves, spanning from similar to 8-185 days after explosion, show that it has a higher peak luminosity (i.e., M-V similar to -17.83 mag at maximum light), a faster post-peak decline, and a shorter plateau phase (i.e., similar to 50 days) compared to the normal Type IIP SN 1999em. The mass of Ni-56 is estimated as 0.02 +/- 0.01 M-circle dot from the radioactive tail of the bolometric light curve. The spectral evolution of SN 2013ej is similar to that of SN 2004et and SN 2007od, but shows a larger expansion velocity (i.e., v(Fe II) similar to 4600 km s(-1) at t similar to 50 days) and broader line profiles. In the nebular phase, the emission of the H alpha line displays a double-peak structure, perhaps due to the asymmetric distribution of Ni-56 produced in the explosion. With the constraints from the main observables such as bolometric light curve, expansion velocity, and photospheric temperature of SN 2013ej, we performed hydrodynamical simulations of the explosion parameters, yielding the. total explosion energy as similar to 0.7x 10(51) erg, the. radius of the progenitor as similar to 600 R-circle dot, and the ejected mass as similar to 10.6M(circle dot). These results suggest that SN 2013ej likely arose from a red supergiant with a mass of 12-13M(circle dot) immediately before the explosion.

A series of numerical models has been constructed for the three-dimensional explosion dynamics of a low-mass neutron star in a binary system that results from the collapse of the rotating iron core of a massive supernova. The numerical solution has been obtained by the particle method with an adaptive time step that allows the computational accuracy to be controlled automatically. The constructed numerical models include the proper motion of the massive component in the binary system of neutron stars, their finite sizes, the graduality of energy release during the explosive disruption of a critical-mass neutron star, and the nonuniform expansion velocity distribution of iron ejecta. The extent to which each of the listed parameters affects the explosion characteristics has been determined. The total explosion energy and the pulsar escape velocity have been estimated. A sizable fraction of the material of the exploded neutron star has been found to remain gravitationally bound to the massive component of the binary system. A further study of its dynamics is of interest in its own right, because the captured material can be considered as an additional source of muon neutrinos.

The problem of incipient joint/fault motion due to a spherical explosion in an infinite homogeneous isotropic rock mass is considered analytically. The mechanical response of intact rock is assumed to be elastic. The shear failure criterion for the joint or fault is taken to be of the usual Mohr-Coulomb form, which results in a single scalar quantity for the definition of the stress states at which failure occurs. In some cases it is found that there exist certain unexpected orientations for which shear failure is inhibited, even though the fault is very close to the source. Also, a quantitative description of catastrophic shear failure on a fault or joint depends on detailed time-resolved stress histories; simple quantitative models based solely on total explosive energy, for example, are incomplete.

I have developed two-dimensional general relativistic magnetohydrodynamic (GRMHD) code. I have performed numerical simulations of collapsars using these codes and realistic progenitor models. In the GRMHD simulation, it is shown that a jet is launched from the center of the progenitor. We also performed two-dimensional hydrodynamic simulations in the context of collapsar model to investigate the explosive nucleosynthesis happened there. It is found that the amount of 56 Ni is very sensitive to the energy deposition rate. This result means that the amount of synthesized 56 Ni can be little even if the total explosion energy is as large as 1052 erg. Thus, some GRBs can associate with faint supernovae. Thus we consider it is quite natural to detect no underlying supernova in some X-ray afterglows.

An analysis over of character of the isodenses of conical charge explosive products, got by mathematical design, is brought. The features of distribution of the power field are certain depending on direction of initiation of the truncated conical charge. The complex character of intermediate initiator using in a downhole charge as the truncated cone at his location in the ground part of hole is discussed. It is established that the shape of the field of isolines of the density of PD is due primarily to the form of the charge, regardless of the place of its initiation; the prevailing field development occurs relative to the Z axis, that is, along the X axis of the conical charge by the action of its narrow part. This is due to the spread of the products of detonation normal to the sloping surface of the cone. If you associate the total area of the PD density field with the total explosive energy, it is possible to redistribute the flow of energy due primarily to the orientation of the bases and sides of the truncated cone charge, and then to its initiation location. Control of the dynamics and direction of development of the force field is possible by choosing the location of application of the initiating pulse, namely, the location of the initiator on the opposite charge basis for the development of the process in the desired direction of concentrating the energy of the explosion. Due to the specific "pear-shaped" form of the radiated energy field, the explosion of the inverted conical fighter at the stage of initiation of the main (downhole) charge directs the vector of the initial section of the stress wave front towards the upper free surface, ie towards the surface sideways. This area is not subject to the direct action of a system of compressive radial and tensile tangential loads from a charge explosion in a well. changing the direction of development of the force field toward the upper layers of the rock should contribute to better grinding of this part of the array. This method can be implemented using the mechanism of interaction of rock masses, moving towards and additionally destroyed similar to the conditions of short-delay blasting in a schematic diagram, ie, the mechanism of interaction at the level of a slower process - the collision (collision) of the mass directed to the upper side. Simultaneous lower initiation of prolonged charges in adjacent rows gives rise to the front edges inclined to the free surface of the ledge (Fig.). In fact, in this case, the scheme of a wedge or trapezoidal cut is implemented, but oriented instead of the lateral free surface towards the roof of the ledge, which because of its large area is the main source of oversized fractions. consists in the simultaneous simultaneous detonation of three adjacent series of downhole charges treated as one group, followed by the short-term detonation of the adjacent three-row group and the like. The implementation of such a scheme allows to take advantage of its advantages by combining mechanisms of movement of masses in the vertical direction and traditional movement with the coincidence of areas of the array in the horizontal direction. The advantages of using a mixed circuit switching scheme have been proven by industrial testing of the method.

In this paper we propose a new plausible mechanism of supernova explosions specific to close binary systems. The starting point is the common envelope phase in the evolution of a binary consisting of a red super giant and a neutron star. As the neutron star spirals towards the center of its companion it spins up via disk accretion. Depending on the specific angular momentum of gas captured by the neutron star via the Bondi-Hoyle mechanism, it may reach millisecond periods either when it is still inside the common envelope or after it has merged with the companion core. The high accretion rate may result in strong differential rotation of the neutron star and generation of a magnetar-strength magnetic field. The magnetar wind can blow away the common envelope if its magnetic field is as strong as 1015 G, and can destroy the entire companion if it is as strong as 1016 G. The total explosion energy can be comparable to the rotational energy of a millisecond pulsar and reach 1052 erg. The result is an unusual type-II supernova with very high luminosity during the plateau phase, followed by a sharp drop in brightness and a steep light-curve tail. The remnant is either a solitary magnetar or a close binary involving a Wolf-Rayet star and a magnetar. When this Wolf-Rayet star explodes this will be a third supernovae explosion in the same binary. A particularly interesting version of the binary progenitor involves merger of a red super giant star with an ultra-compact companion, neutron star or black hole. In the case if a strong magnetic field is not generated on the surface of a neutron star then it will collapse to a black hole. After that we expect the formation of a very long-lived accretion disk around the black hole. The Blandford-Znajek driven jet from this black hole may drive not only hypernovae explosion but produce a bright X-ray transient event on a time scale of 104 s.

I have developed two‐dimensional general relativistic magnetohydrodynamic (GRMHD) code. I have performed numerical simulations of collapsars using these codes and realistic progenitor models. In the GRMHD simulation, it is shown that a jet is launched from the center of the progenitor. We also performed two‐dimensional hydrodynamic simulations in the context of collap‐sar model to investigate the explosive nucleosynthesis happened there. It is found that the amount of 56Ni is very sensitive to the energy deposition rate. This result means that the amount of synthesized 56Ni can be little even if the total explosion energy is as large as 1052 erg. Thus, some GRBs can associate with faint supernovae. Thus we consider it is quite natural to detect no underlying supernova in some X‐ray afterglows.

The advent of nuclear weapons not only has introduced a means by which massively large explosive power may be attained but also has given the general public its baptism of fear of ionizing radiation—a fleeting, unseen, unfelt messenger of death. This new and poorly understood phenomenon has so capitivated the minds of the public, as well as of many students, that they have overlooked the fact that thermal and mechanical trauma will be of much greater importance in a nuclear explosion of any large magnitude and, furthermore, that there is some hope of medical care being given for these types of trauma, while there is not yet any specific practical therapy for ionizing radiation. These statements are supported by data on the portions of the total explosive energy in nuclear explosions which are delivered as a blast (50%), initial ionizing radiation (5%), residual ionizing radiation (fall-out) (10%), and thermal radiation