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Jiang, Shangyuan, Ariana N. Gannon, Kyle D. Smith, Marcus Brown, Junfeng Liang i Rong Z. Gan. "Prevention of Blast-induced Auditory Injury Using 3D Printed Helmet and Hearing Protection Device – A Preliminary Study on Biomechanical Modeling and Animal". Military Medicine 186, Supplement_1 (1.01.2021): 537–45. http://dx.doi.org/10.1093/milmed/usaa317.
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ABSTRACT Introduction Repeated blast exposures result in structural damage to the peripheral auditory system (PAS) and the central auditory system (CAS). However, it is difficult to differentiate injuries between two distinct pathways: the mechanical damage in the PAS caused by blast pressure waves transmitted through the ear and the damage in the CAS caused by blast wave impacts on the head or traumatic brain injury. This article reports a preliminary study using a 3D printed chinchilla “helmet” as a head protection device associated with the hearing protection devices (e.g., earplugs) to isolate the CAS damage from the PAS injuries under repeated blast exposures. Materials and Methods A finite element (FE) model of the chinchilla helmet was created based on micro-computed tomography images of a chinchilla skull and inputted into ANSYS for FE analysis on the helmet’s protection against blast over pressure. The helmet was then 3D printed and used for animal experiments. Chinchillas were divided into four cases (ears open, with earplug only, with both earplug and helmet, and with helmet only) and exposed to three blasts at blast over pressure of 15 to 20 psi. Hearing function tests (e.g., auditory brainstem response) were performed before and after blast on Day 1 and Days 4 and 7 after blasts. Results The FE model simulation showed a significant reduction in intracranial stress with the helmet, and the animal results indicated that both earplug and helmet reduced the severity of blast-induced auditory injuries by approximately 20 dB but with different mechanisms. Conclusions The biomechanical modeling and animal experiments demonstrated that this four-case study in chinchillas with helmet and hearing protection devices provides a novel methodology to investigate the blast-induced damage in the PAS and CAS.
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Hussein, Assal, Hussam Mahmoud i Paul Heyliger. "Probabilistic analysis of a simple composite blast protection wall system". Engineering Structures 203 (styczeń 2020): 109836. http://dx.doi.org/10.1016/j.engstruct.2019.109836.
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EL. Mukhtar, Majdi, i Abdelmonim A. Haroun. "Analysis of Blast Resistant Structure (TNT Storage Case Study)". FES Journal of Engineering Sciences 9, nr 1 (5.10.2019): 1–5. http://dx.doi.org/10.52981/fjes.v9i1.639.
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The explosions produce extreme and unique loading on structures and can cause widespread damage to the building’s structural elements. Design of blast resistant structures provides structural integrity and acceptable levels of safety for buildings. The previous studies show that some structural systems could provide substantial increase in protection against blasts. This paper discussed the behavior of TNT loaded storage (a framed reinforced concrete (. the results of calculated pressure Using Reference (UFC)-3-340-02 [1] Equation and investigated that the average peak reflected pressure close to 5000 Psi. CSI-ETABS Software 3D model shows that the structural system of case study unsafe under 0.5 tons of TNT internal weight charge.
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Goel, M. D., N. S. Choudhary i Sandeep Panchal. "Comparative Analysis of Aluminum Alloy 6061-T6 and Mild Steel Tubes in Sacrificial Protection System under Blast Loading". Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, nr 1 (19.12.2022): 1299–304. http://dx.doi.org/10.38208/acp.v1.654.
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A sacrificial cladding consist of hollow metal tubes and steel sheet, is proposed in this study to protect a square concrete panel subjected to blast loading. Herein, comparative analysis of aluminum alloy 6061-T6 (Al 6061-T6) and mild steel tubes in sacrificial cladding is done using 3-D non-linear Finite Element (FE) software ABAQUS/Explicit®. Blast load is applied through ConWep program developed by US Army. Simplified Concrete Damage Plasticity (SCDP) model is used to define the material behavior of concrete slabs of thickness 250 mm. Johnson-Cook (J-C) plasticity model is used to model the stress-strain response of Al 6061-T6 and mild steel tubes, reinforcement bars and steel sheet. Diameter (D) and thickness (t) of circular metal hollow tubes are taken from IS1161:1998. Comparative analysis of Al 6061-T6 and mild steel tubes is carried out for blast loading using TNT with scaled distance of 0.425 m/kg1/3. It was observed that mild steel tubes perform better than Al 6061-T6 tubes and save concrete panel from degradation under blast loading.
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Khalifa, Yasser A., Mohamed N. Lotfy i Elsayed Fathallah. "Effectiveness of Sacrificial Shielding for Blast Mitigation of Steel Floating Pontoons". Journal of Marine Science and Engineering 11, nr 1 (4.01.2023): 96. http://dx.doi.org/10.3390/jmse11010096.
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Floating pontoons have played a supreme and indispensable role in crises and disasters for both civil and military purposes. Floating bridges and ferries are exposed to blast loadings in the case of wars or terrorist attacks. The protection effectiveness of sacrificial cladding subjected to a blast was numerically investigated. In this study, a steel ferry has been simulated and exposed to side explosions with different explosive charges at certain stand-off distances, according to military standards from NATO and American standard TM5. In this simulation, nonlinear three-dimensional hydro-code numerical simulation ANSYS autodyn-3d has been used. The results reported that the ferry could withstand a charge of 5 kg TNT at a stand-off distance of 1 m without failure. The main objective of this research is to achieve a design that would increase the capacity against the blast loading with minimal plastic deformation in the absence of any failure in the ferry. Therefore, an innovative mitigation system has been proposed to dissipate the blast energy of the explosion based on the scientific theory of impedance using sacrificial cladding. The new mitigation system used a specific structural system in order to install the existing pontoon structure without any distraction. The response, elastic deformations, plastic deformations and plastic failure of the ferry were illustrated in this paper. Furthermore, the results revealed that the proposed mitigation system could mitigate more than 50% of the blast waves. The new design revealed promising results, which makes it suitable for mitigating blast waves. Finally, the results were provided with a reference for the preliminary design and application of sacrificial cladding for structural protection against blast waves.
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Ivančo, Matúš, Jovan Trajkovski, Lucia Figuli i Romana Erdélyiová. "Determination of blast resistance of selected structural elements". MATEC Web of Conferences 313 (2020): 00026. http://dx.doi.org/10.1051/matecconf/202031300026.
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At the present time of political and war conflicts between countries, more and more attention is focused on the protection of important structures, being part of critical infrastructure, such as buildings of energy importance, government buildings or military bases. Regardless of the type of industry area, primarily, buildings needed to be protected. For this reason, the paper is focused on the determination of resistance of selected structural elements creating the protection system against the effects of the blast from the explosion, including terrorist attack. The paper has need of analysing the behaviour of structural elements affected by the blast load and setting the structural resistance of elements loaded by such dynamic type of load. The outputs can serve as a basis for the design of an effective plan for the protection of a selected elements of critical infrastructure, which ultimately represents not only the protection of the buildings themselves, but also the affected people presented inside the buildings.
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Mashee, Fouad K. "Estimation the blast wave pressure effecters by apply Remote Sensing (RS) and Geographic Information System (GIS) techniques". Iraqi Journal of Physics (IJP) 15, nr 34 (8.01.2019): 87–98. http://dx.doi.org/10.30723/ijp.v15i34.124.
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After the year 2003 terrorist attacks knock Baghdad city capital of Iraq using bomb explosion various, shook the nation, and made public resident of Baghdad aware of the need for better ways to protect occupants, assets, and buildings cause the terrorist gangs adopt style burst of blast to injury vulnerability a wider range form, and many structures will suffer damage from air blast when the overpressure concomitant the blast wave, (i.e., the excess over the atmospheric pressure 14.7 pounds per square inch at standard sea level conditions are about one-half pound per square inch or more(to attainment injury. Then, the distance to which this overpressure level will extend depends primarily on the energy yield (§1.20) of the burst of blast. Accordingly, must been have adopted a changing philosophy to provide appropriate and effective protection for preservation of psyche and building occupants, by establishment of a protected perimeter and the design of a debris mitigating facade, the isolation of internal explosive threats that may to dodge detection through the screening stations or may enter the public spaces prior to screening and the protection of the emergency evacuation, rescue and recovery systems. By reason of this above-mentioned, the study simple contribution of determined phenomena risk containment. Moreover, in this study may be applied remote sensing (RS) and geographic information system (GIS) techniques to estimation the blast wave overpressure of bomb explosive effecters for damage that building of materials (i.e., facade, building glass, secondary of roof, fashioning tools and furniture), and how avoid this problem, therefore, selection justice ministry of Iraq building in Salehyiea region at Baghdad city, it destroyed at 28/10/2009 by motocar bombs explosion.
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Grujicic, M., R. Yavari, J. S. Snipes i S. Ramaswami. "A zeolite absorbent/nano-fluidics protection-based blast- and ballistic-impact-mitigation system". Journal of Materials Science 50, nr 5 (17.12.2014): 2019–37. http://dx.doi.org/10.1007/s10853-014-8779-x.
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Khan, Rizwan, Syed Hassan Farooq i Muhammad Usman. "Blast Loading Response of Reinforced Concrete Panels Externally Reinforced with Steel Strips". Infrastructures 4, nr 3 (18.08.2019): 54. http://dx.doi.org/10.3390/infrastructures4030054.
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Frequent terrorist activities, the use of vehicle bomb blasts and improvised explosive devices (IEDs) have brought forth the task of protection against blasts as a priority issue for engineers. Terrorists mostly target the areas where human and economic losses are significantly higher. It is really challenging to study the effects of blast loading on structures due to numerous variables. For instance, the type of detonation charge, explosive material, placement of charge and standoff distance, etc., are a few of the variables which make the system more complicated. Reinforced cement concrete (RCC) wall panels are commonly used for protecting important installations and buildings. In this research, the response of RCC wall panels has been investigated due to the blast effect caused by two TNT charge weights of 50 kg and 100 kg. These two charge weights have been selected after a detailed study of terrorist activities in the recent past. For this purpose, an existing arrangement at an important military installation, i.e., NESCOM Hospital Islamabad in Pakistan, has been selected. To reduce computational efforts, three RCC wall panels, placed side by side producing a continuous front along with a corresponding boundary and structural wall, have been considered. RCC wall panels are placed at a distance of 3 ft from the perimeter of the boundary wall and 23 ft from the structural wall. The displacement on the front face of RCC wall panels and the structural wall is measured at three levels of top, middle and bottom. ANSYS AUTODYN software has been used to simulate the model. Analysis has been carried out to identify and study the weakness of existing arrangements. Literature was reviewed for suggesting an appropriate strengthening technique for existing structures against blast loading. It was found that in addition to existing strengthening techniques, use of steel strips is amongst the most feasible technique for strengthening existing structures. It not only significantly enhanced the blast performance of structures, but it also significantly reduced z-direction displacements and pressures. The results show that the use of steel strips as the improvement technique for already placed RCC wall panels can be effective against a blast loading of up to 100 kg TNT.
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Bondar, V. S., Y. M. Temis i M. V. Biryukov. "Determination of optimal parameters of damper system for explosion protection of a structure on the basis of foam aluminum". Izvestiya MGTU MAMI 8, nr 4-4 (20.08.2014): 15–17. http://dx.doi.org/10.17816/2074-0530-67326.
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The authors considered the use of sandwich packs as protection of a technical object from the explosion. A comparative study of the effect of blast waves of varying intensity on the deformation of the sandwich package was conducted. Optimal characteristics of a sandwich package were founded.
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Zhang, Xuejian, Xiaojuan Wang, Hongyuan Zhou, Wenxue Zhang, Tianyi Song, Yonghui Wang i Hong Zhang. "Improving blast protection of double-layered system for infilled masonry wall in frame structure". Thin-Walled Structures 190 (wrzesień 2023): 110953. http://dx.doi.org/10.1016/j.tws.2023.110953.
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Kciuk, Sławomir, Edyta Krzystała, Arkadiusz Mężyk i Paweł Szmidt. "The Application of Microelectromechanical Systems (MEMS) Accelerometers to the Assessment of Blast Threat to Armored Vehicle Crew". Sensors 22, nr 1 (31.12.2021): 316. http://dx.doi.org/10.3390/s22010316.
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This paper describes the development and application of an autonomous register and measurement system (ARMS), and the application of microelectromechanical systems (MEMS) accelerometers to the assessment of blast threat to armored vehicle crews. Taking measurements with reference to an explosion is one of the principal issues in the protection of crews of special vehicles. The proposed ARMS reduces research costs and contributes to the development of an autonomous, wireless test stand, applicable in various research areas and industry. The ARMS performs data acquisition with simultaneous measurement in multiple channels. The maximum sampling rate is 100 kHz and the sensor range is ±500 g. This solution is an alternative to cable systems, which have a high energy demand. The functionality of the developed autonomous measuring system is demonstrated experimentally. The paper concludes with a field study of the proposed system and the application of MEMS accelerometers via a mine blast test of a military vehicle at level 4 of STANAG 4569.
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Codina, Ramón, Daniel Ambrosini i Fernanda de Borbón. "New sacrificial cladding system for the reduction of blast damage in reinforced concrete structures". International Journal of Protective Structures 8, nr 2 (5.04.2017): 221–36. http://dx.doi.org/10.1177/2041419617701571.
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Over the past few decades, explosive devices have become the weapon of choice for many terrorist attacks. In some of these attacks, large amounts of explosives are detonated within a short distance of building structures. It has been shown that current design methods are inadequate for the prevention of progressive collapse. The protection of key elements, such as columns, is necessary to prevent this catastrophic response sufficiently. This article discusses the performance of a new sacrificial cladding that protects reinforced concrete members under blast loading. It consists of reinforced resin panels with an insulation layer. For comparison purposes, two reinforced concrete members were previously experimentally studied, a reinforced concrete column without protection and reinforced concrete column with classical steel jacketing. It can be observed from the experimental results that the new sacrificial cladding achieves an important reduction in damage and displacements.
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Alogla, Ageel, Mahmoud Helal, Mohamed Mokbel ElShafey i Elsayed Fathallah. "Numerical Analysis for Critical Structures Protection against Blast Loading Using Metallic Panels". Applied Sciences 10, nr 6 (20.03.2020): 2121. http://dx.doi.org/10.3390/app10062121.
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The need for building protection against blast loads is a crucial issue nowadays due to the escalating threat of terrorist attacks, which affect people’s lives and critical structures. Consequently, design of protective panels to segregate building façades from the effect of a nearby explosion is required. Such design mainly depends on the ability of protective panels to mitigate and diffract the blast wave before reaching building façades. Five protective panel models with different designs, referred to as the Combined Protection System (CPS), are introduced in this paper. The main objective of this research was to achieve a design that could sustain a blast load with minimum plastic deformations. The introduced CPS designs included two steel plates linked by connector plates. The CPS dimensions were 3 m × 3 m × 0.35 m, representing length, width, and height, respectively. After that, the successful panel design was supported by placing these panels onto a masonry wall in different configurations. The protective panels were tested against 50 kg of trinitrotoluene (TNT) with a standoff distance of one meter. The final run of the optimum model was carried out using a blast load equivalent to 500 kg of TNT. The air–structure interactions were simulated using finite element analysis software called “ANSYS AUTODYN”, where the deformation of the panel was the governing parameter to evaluate the behavior of different designs. The analysis showed minimum deformation of the CPS design with vertical and horizontal connecting plates in a masonry wall distanced at 500 mm from the panel. However, the other designs showed promising results, which could make them suitable for critical structural protection on different scales.
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Asprone, D., A. Prota, G. Manfredi i A. Nanni. "Behavior of Full-Scale Porous GFRP Barrier under Blast Loads". International Journal of Polymer Science 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/349310.
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This research paper is part of the SAS (Security of Airport Structures) Project funded by the European Programme for Critical Infrastructure Protection, whose objective was to develop and deploy a fiber reinforced polymer (FRP) fencing system intended to protect airport infrastructures against terrorist acts. In the paper, the efficacy of the proposed glass FRP discontinuous (porous) barrier under blast loads is presented by showing the results of the blast test campaign conducted on full-size specimens with a focus on the reduction of the blast shock wave induced by the barrier. A simplified model predicting the reduction of the shock wave beyond the barrier is proposed and validated via the experimental data obtained in the project.
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Mára, Michal, Candida Talone, Radoslav Sovják, Jindřich Fornůsek, Jan Zatloukal, Přemysl Kheml i Petr Konvalinka. "Experimental Investigation of Thin-Walled UHPFRCC Modular Barrier for Blast and Ballistic Protection". Applied Sciences 10, nr 23 (5.12.2020): 8716. http://dx.doi.org/10.3390/app10238716.
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The static response of ballistic panels and also its resistance to blast and ballistic impact is investigated in the framework of this study. By connecting individual ballistic panels together, the protective barrier can be constructed. The protective barrier can be featured as a system with high mobility and versatility that is achieved by linking basic interlocking plate elements together. The resulting protective barrier can be shaped according to many possible scenarios in a wall with various possible opening angles and a small post with the tetragonal base or a larger post with the hexagonal ground plan. The material solution of the protective barrier benefits from the application of ultra-high-performance fibre-reinforced cement-based composites (UHPFRCC), which meets the requirements for enhanced resistance against extreme loads such as blast or impact. Besides, by using UHPFRCC, thin and slender design can be adopted, which is advantageous in many ways. Slender design results in a lower weight, allowing for easy manipulation and replacement. To verify the behavior of the panels, the proposed barrier was subjected to various loadings at different strain rates. The experimental campaign demonstrated that the protective barrier has a reasonable load-bearing capacity and also sufficient resistance against projectile impact and blast effects.
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Zheng, Haifeng, Congchong Ru, Chang Wen Chen i Lun Yu. "Video Transmission over MIMO-OFDM System: MDC and Space-Time Coding-Based Approaches". Advances in Multimedia 2007 (2007): 1–8. http://dx.doi.org/10.1155/2007/61491.
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MIMO-OFDM is a promising technique for the broadband wireless communication system. In this paper, we propose a novel scheme that integrates multiple-description coding (MDC), error-resilient video coding, and unequal error protection strategy with hybrid space-time coding structure for robust video transmission over MIMO-OFDM system. The proposed MDC coder generates multiple bitstreams of equal importance which are very suitable for multiple-antennas system. Furthermore, according to the contribution to the reconstructed video quality, we apply unequal error protection strategy using BLAST and STBC space-time codes for each video bitstream. Experimental results have demonstrated that the proposed scheme can be an excellent alternative to achieve desired tradeoff between the reconstructed video quality and the transmission efficiency.
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Khan, M. A. I., M. A. Ali, M. A. Monsur, A. Kawasaki-Tanaka, N. Hayashi, S. Yanagihara, M. Obara, M. A. T. Mia, M. A. Latif i Y. Fukuta. "Diversity and Distribution of Rice Blast (Pyricularia oryzae Cavara) Races in Bangladesh". Plant Disease 100, nr 10 (październik 2016): 2025–33. http://dx.doi.org/10.1094/pdis-12-15-1486-re.
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The pathogenicity of 331 blast isolates (Pyricularia oryzae Cavara) collected from different regions and ecosystems for rice cultivation in Bangladesh was evaluated by compatibility on 23 differential varieties (DV), each harboring a single blast resistance gene, and susceptible ‘Lijiangxintuanheigu’ (LTH). A wide variation in virulence was found among the isolates, and 267 races were classified using a new designation system. Virulence of blast isolates against DV carrying the resistance genes Pia, Pib, Pit, Pik-s, Piz-t, Pi12(t), Pi19(t), and Pi20(t), as well as avirulence against those carrying Pish, Pi9, Pita-2, and Pita, was distributed widely in Bangladesh. Cluster analysis of the compatibility data on the DV initially classified the isolates into groups I and II. The virulence spectra of the two groups differed mainly according to the reactions of the DV to Pii, Pi3, Pi5(t), Pik-m, Pi1, Pik-h, Pik, Pik-p, and Pi7(t). Group I isolates were distributed mainly in rainfed lowlands, whereas group II isolates were found mainly in irrigated lowlands; however, there were no critical differences in geographic distribution of the blast isolates. In total, 26 isolates, which could be used to identify the 23 resistance genes of the DV on the basis of their reaction patterns, were selected as a set of standard differential blast isolates. To our knowledge, this is the first clear demonstration of the diversity and differentiation of blast races in Bangladesh. This information will be used to develop a durable blast protection system in that country.
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Grujicic, Mica, Ramin Yavari, Jennifer Snipes i S. Ramaswami. "Mitigation of blast and impact loading via the use of a zeolite-absorbent/nano-fluidics protection system". International Journal of Structural Integrity 6, nr 3 (8.06.2015): 367–89. http://dx.doi.org/10.1108/ijsi-09-2014-0041.
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Purpose – In the present work, a new blast-/ballistic-impact mitigation concept is introduced and its efficacy analyzed using advanced computational methods and tools. The concept involves the use of a zeolite protective layer separated by air from the structure being protected and in contact with a water layer in front. The paper aims to discuss these issues. Design/methodology/approach – To properly capture the attendant nano-fluidics phenomena, all the calculations carried out in the present work involved the use of all-atom molecular-level equilibrium and non-equilibrium molecular-dynamics simulations. Findings – Under high-rate loading, water molecules (treated as a nano-fluidic material) are forced to infiltrate zeolite nanopores wherein, due to complex interactions between the hydrophobic nanopore walls and the hydrogen bonds of the water molecules, water undergoes an ordering-type phase transition and acquires high density, while a significant portion of the kinetic energy of the water molecules is converted to potential energy. Concomitantly, a considerable portion of this kinetic energy is dissipated in the form of heat. As a result of these energy conversion/dissipation processes, the (conserved) linear momentum is transferred to the target structure over a longer time period, while the peak loading experienced by the structure is substantially reduced. Originality/value – To the authors’ knowledge, the present work constitutes the first reported attempt to utilize pure SiO2 hydrophobic zeolites in blast-/ballistic-impact protection applications.
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Balos, Sebastian, Daniel Howard, Adrian Brezulianu i Danka Labus Zlatanović. "Perforated Plate for Ballistic Protection—A Review". Metals 11, nr 4 (24.03.2021): 526. http://dx.doi.org/10.3390/met11040526.
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In recent years, the interest of the scientific community in perforated plates for ballistic protection has increased. Perforated plates do not represent protection by themselves, rather, they are used in the armour systems of armoured vehicles, in conjunction with base armour, since they are intended to induce bend stresses, where a penetrating core fracture occurs. The fragments are subsequently stopped by base armoured vehicle armour. Although for the first time used several decades ago, perforated plates are found to be attractive even today. The main reason is the combination of very convenient properties. Besides high mass effectiveness, they possess a high multi-impact resistance, since their perforations arrest cracks. Therefore, a relatively wide array of materials is suitable for perforated plate fabrication, ranging from alloy steel to some types of cast iron. Being made of metallic materials, raw material costs are relatively low compared to ceramics or composite materials, making them very attractive for present and future armoured vehicles. Finally, armour system consisting of a perforated plate and base plate at some distance, reduce the effectiveness of both shaped charge jets and act as blast mitigators.
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Ivo Uglešić, Igor Ivanković i Viktor Milardić. "Transients Caused by Sequential Circuit Breaker Tripping Issued by Busbar Protection". Journal of Energy - Energija 59, nr 1-4 (22.08.2022): 19–24. http://dx.doi.org/10.37798/2010591-4273.
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A study of transients in a high voltage substation 400/110 kV is presented in the paper. An analysis was carried out after a fault on the 110 kV busbar, which caused severe damage in the substation. Investigation was focused on a time frame of several sequential circuit breaker trippings. A first step of the study was collection of data from the primary and secondary system in the substation and the control centre. After numerous analyses of data an attempt was made to construct a precision model, which could be used in the computation. Appropriate models were developed for circuit breakers, voltage (potential) and current metering transformers, power transformers, surge arresters, overhead lines and an equivalent grid. The components of the power system can be modelled for the very particular purpose, which means that a different frequency model should be used and each element in this analysis has a specific frequency response. An attempt was made at very detailed modelling of a power transformer, air blast and SF6 circuit breakers. Computed results of fault currents were compared with measurements captured by the disturbance recorders in the field, mainly in differential numerical relays. Different switching schemes and different tripping sequences of several 110 kV circuit breakers were analysed with a constructed model in the millisecond range. Models of circuit breaker with different types of media, air blast and SF6 gas were used in the cases investigated. Modelling of the circuit breakers’ electrical arc was an important item in all cases in order to take into account the interaction between electrical arc and circuit current during the process of current interruption. The Schwarz/Avdonin equation is applied to model the dynamic behaviour of an electric arc. The fault studied was accompanied by a large short circuit current. For this particular case two types of circuit breaker, air blast and SF 6 were modelled. An important conclusion from those analyses was that sequential tripping of several circuit breakers does not cause superposition of overvoltages, because interruption the current happens when it is passing through the zero. Even the record from the substation and the disturbances recorder proves that each particular circuit breaker was successfully opened. On that basis, focus was put only on the final opening of the breaker and its arc extinction. The conclusion can be drawn that such a substation fault should have no influence on excessive overvoltages that can threaten the insulation of components in the substation.
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Khomeriki, David, Nikoloz Chikhradze, Edgar Mataradze, Mikheil Chikhradze, Karlo Tavlalashvili i Shalva Marjanishvili. "Wireless device for the detection of explosions and activation of a shock wave absorber". MATEC Web of Conferences 305 (2020): 00092. http://dx.doi.org/10.1051/matecconf/202030500092.
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Existing problems of security is strongly connected to terrorist and accident explosions and fires. Physical protection of critical infrastructure requires the creation of reliable system providing quick and accurate identification of the hazards and subsequent transmission of the alarm signal to the protection device. The paper describes the basic requirements and structure of the wireless device for the detection of explosions. Proposed wireless device consists of transmitter and receiver modules. A transmitter module contains the sensors and a microprocessor equipped with a blast identification software. A receiver module produces an activation signal for the operation of protection devices. The paper presents the test results of the proposed wireless device, carried out in the underground experimental base of the G. Tsulukidze Mining Institute.
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Jia, Xiao-liang. "Experimental study on performance of high purity nitrogen supply system in liquefaction unit of low concentration coalbed methane". E3S Web of Conferences 267 (2021): 02076. http://dx.doi.org/10.1051/e3sconf/202126702076.
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Aiming at the problems such as low CBM utilization rate caused by low concentration CBM with methane content less than 8% extracted from a small coal mine in Hancheng mining area, Shaanxi Province, and serious environmental pollution caused by coal-fired hot blast stove for heating, the heat storage and oxidation heating technology of ultra-low concentration gas in small coal mine was studied by combining field investigation and heat balance calculation. This technology replaces the coal-fired hot blast stove, realizes “coal and CBM mining and sharing” in the coal mine, and constructs a virtuous cycle development of “promoting drainage by using and promoting safety by drainage”. The research shows that: the scheme improves the utilization rate of CBM in the mining area, cancels the consumption of coal combustion, and can use 2.59 million Nm3 of pure CBM every year, generating 1.95 million yuan of economic benefits. And the emissions reduction of CO2 equivalent is 36000 tons. The benefits of safety, economy and environmental protection are remarkable. This technology is especially suitable for the utilization of ultra-low concentration CBM whose concentration is less than 8%, which has practical significance to improve the CBM utilization rate and promote the realization of the goal of “zero emission”.
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Qi, Xin, Hu Xu, Zhixiang Yu, Keqin Sun i Shichun Zhao. "Full-Scale Test and Numerical Simulation of Guided Flexible Protection System under a Blasting Load". Environmental and Engineering Geoscience 26, nr 2 (27.05.2020): 243–56. http://dx.doi.org/10.2113/eeg-2256.
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ABSTRACT Both active and passive flexible protection methods are effective against rockfalls, but they can result in a secondary hazard due to cumulate rocks inside the structure. To solve this problem, guided flexible protection systems are receiving increased attention in the engineering community. In this study, a full-scale test of a guided flexible protection system was carried out, where the bottom of the mesh was anchored under a blasting load, which can be considered as an extreme loading event related to rockfall hazards. The fluid-solid coupling method was employed in a finite element model to simulate the entire process from the blast to the accumulation of rocks at the bottom of the slope. Based on the experimental and numerical results, a two-stage process was revealed, the internal force and the dissipated energy of each component were compared and analyzed, and the load-transferring path within the system was obtained. The internal forces of the support ropes reached their maximum values in the intercept stage. The posts experienced two peak values, the first of which, in the guide stage, was twice that in the intercept stage. The brake rings were the main energy-dissipating components, and the energy dissipation in the intercept stage was much greater than that in the guide stage. Furthermore, the interaction in terms of collision and friction between the rocks, the slope, and the system was not insignificant, particularly in the guide stage, which can account for more than 40 percent of the consumed energy of the rockfall.
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Sharifi, Yasser, i Hamed Aviz. "Effect of outrigger-belt truss location on the dynamic response of high-rise building subjected to blast loading". Journal of Engineering, Design and Technology 14, nr 1 (7.03.2016): 54–77. http://dx.doi.org/10.1108/jedt-12-2013-0084.
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Purpose – Nowadays, with the expansion of terrorist operations around the world and also the dangers of accidental explosions, the need to design structures resistant to this phenomenon for the protection and safety of its citizens is inevitable. Tall buildings are one of the most important issues because of which those behavior should be investigated against the blast loading. Design/methodology/approach – In this paper, the authors used a simple method for investigating the dynamic response of tall buildings with the combined system of framed tube, shear core and outrigger-belt truss located at different heights of the building’s that were subjected to blast loading. This proposed model is based on the development of a continuum model and the ruling equations that have been obtained using the energy principle predict the whole structure idealized as a shear and flexural cantilever beam with rotational springs at the belt truss location. Findings – The mathematical procedure shows a good understanding of the structural behavior and is suitable for a quick evaluation during the preliminary design stage, which requires less time. Moreover, it was concluded that the present blast load idealization can be used to reasonably assess the response of tall buildings subjected to blast load. Originality/value – The comparative analysis in this paper could give other engineers a simple analysis method for the preliminary analysis and design of tall building analysis. Numerical example is given to illustrate the ease of application and the accuracy of the suggested model.
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Zvakova, Zuzana, Martin Boros, Lucia Figuli i Andrej Velas. "Evaluation Process of the Burglary Resistance When Explosives Are Used to Create an Opening in the Barriers". Symmetry 13, nr 9 (18.09.2021): 1740. http://dx.doi.org/10.3390/sym13091740.
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Burglary resistance expresses the time required to overcome the barriers to cause the damage in order to unlawfully enter a place for the purposes of stealing property or committing a felony (i.e., disruption of important assets, e.g., critical infrastructure). Damage to the object protection system means damage to the symmetry of the system—the balance between protection measures and security threats. Barriers are considered to be the walls of buildings or secure storage units (safe, safe, etc.), i.e., passive barriers that separate asset (protected value) from the security threat. The role of barriers in the security system is also to slow down the attack and create a time reserve for the intervention of a security service. There is no uniform approach to express the burglary resistance of such barriers using explosives; however, burglary by explosion are present. Explosives in the article are a tool that can be used by the offenders. The article uses mainly Delphi method and Saaty method. These methods have made it possible to identify and expertly evaluate scenarios for the use of explosives to break a barrier. Logical methods and interviews were also used. The result of the article is the identification and evaluation of the possibilities of using explosives to overcome barriers and expressing the blast burglary resistance of barriers. The universal assessment approach allows the inclusion of explosives to the burglary resistance protection system assessment schemes.
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Brown, Samuel J. "Energy Release Protection for Pressurized Systems. Part II: Review of Studies Into Impact/Terminal Ballistics". Applied Mechanics Reviews 39, nr 2 (1.02.1986): 177–201. http://dx.doi.org/10.1115/1.3143704.
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In order to assess whether or not there is a need for protection against the failure of a pressure system, the engineer must evaluate the hazards associated with rupture. The hazards are divided into two categories: (a) force/displacement and (b) degenerative. Force/displacement is classified into (1) kinetic energy associated with the atmosphere: blast, (2) kinetic energy of objects (fragmentation and impact of missiles), and (3) kinetic energy associated with foundations: soil foundation motion. The first article of this series [Energy release protection from pressurized systems: Part I Review of studies into blast and fragmentation, Appl Mech Rev38 (Dec), 1625–1651 (1985)] has set the stage for this paper, which reviews the studies into predicting the performance (mechanics) of a receptor (target, containment, barricade, shelter) that is impacted by a missile. The study into the prediction of target missile performance or terminal ballistics has occupied interests of man since the development of a projectile as a weapon. One of the earliest publications of terminal ballistics is reported by Robins (1742). A number of experimental studies during the 1800s are reported by Holie (1950). These early experiments set the pattern for the reliance on experimental programs to define semiempirical formula to predict missile–target responses (such as penetration, perforation, spalling, and scabbing) into the 20th century. This is due to the fact that theoretically derived equations to predict missile target performance have enjoyed only limited success because of the complexity of the problems to be solved. Numerical methods essentially had to wait for the development of the high speed digital computers in the early 1960s. Historically the finite difference methods have received the earliest use in simulating impact. They tend to be more computationally cost effective than finite element programs. However, because of the generality of the finite element method to idealize structures geometrically for a considerable range of mechanics problems, it has received the greater attention of research and development over the last two decades and is capable of solving wave propagation, nonlinear material, and nonlinear large deformation problems. The computer codes developed to solve impact problems are generally characterized as either Lagrangian or Eulerian. In this paper, a brief discussion will be provided covering the development of target/missile formulas, associated experimental programs and numerical methods.
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Liesveld, Jane L., Jeffrey E. Lancet, Karen E. Rosell, Jeremy Bechelli, Camille N. Abboud i Gordon L. Phillips. "The CXCR4 Antagonist, AMD3100, Inhibits AML Transmigratory Activity but Does Not Alter Blast Proliferation or Survival." Blood 104, nr 11 (16.11.2004): 2881. http://dx.doi.org/10.1182/blood.v104.11.2881.2881.
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Abstract Stromal cell derived factor-1 (SDF-1α) and its receptor, CXCR4 play a role in the trafficking of CD34+ cells. AMD3100, a selective CXCR4 antagonist, can mobilize hematopoietic progenitors from marrow to peripheral blood in healthy human volunteers and in patients with multiple myeloma and non-Hodgkin’s lymphoma (Flomenberg et al, Blood 102, 39a, 2003). Overexpression of CXCR4 on human CD34+ progenitors increases their proliferation and NOD/SCID repopulating capacity (Kahn et al. Blood 103:2942, 2004). Since CXCR4 has been found to regulate the migration and development of AML stem cells in NOD/SCID mice, we studied the effect of AMD3100 on AML cells from the standpoint of proliferation and in vitro transendothelial transmigration utilizing a transwell system. AMD3100 (from AnorMED, Inc.), at concentrations from 0.1 to 1.0 ng/ml did not affect the viability or porliferation of purified AML blasts (n=4). AMD3100 did not influence the adherence of AML blasts to endothelial monolayers. In the presence of 0.1 to 1 ng/ml AMD-3100, the transmigration of normal CD34+ cells stimulated by 100 ng/ml SDF-1α through a human umbilical vein endothelial cell (HUVEC) monolayer was completely inhibited. Likewise, the transmigration of AML blasts through HUVECs was not altered by AMD3100 exposure, but the SDF-1α mediated transmigration was inhibited by AMD3100 from 0.1 to 1 ng/ml. The same effect was noted with AML transmigration through marrow stromal layers. The increase in transmigration through endothelial cells stimulated with G-CSF was not inhibited by AMD3100 whereas the transmigration stimulated by interleukin-8 was inhibited. When AMD3100 was placed in the bottom of the migration chamber, no independent effects on AML transmigration were noted. Co-culture of AML blasts with stromal monolayers protected blasts from apoptosis. This protection was not altered by SDF-1α, AMD3100, nor by the combination. These in vitro results demonstrate that AMD3100 can influence the migratory capacity of AML cells but has no direct effects on their proliferation or survival. Further in vitro and in vivo studies will be required to elucidate the role that this unique chemokine antagonist has in the mobilization potential of AML blasts or progenitors or in the interactions of AML cells with their microenvironment. Such studies have implications for AML autografting and AML blast interactions with extramedullary endothelial cells.
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Britch, Seth C., Kenneth J. Linthicum, Robert L. Aldridge, Todd W. Walker, Mattie J. E. Rush, Matthew D. Aubuchon i Jerry D. Kerce. "Residual Pesticide On Hesco® Blast Protection Wall In Temperate Florida Habitat Effective Against Mosquitoes, Stable Flies, and Sand Flies". Journal of the American Mosquito Control Association 34, nr 3 (1.09.2018): 224–32. http://dx.doi.org/10.2987/18-6754.1.
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ABSTRACT United States military troops in the field are exposed to the environment and are thus at high risk for transmission of arboviruses, and degradation of mission from continual harassment from insects. Passive vector control, such as application of residual insecticides to US military materials common in the field such as tents and camouflage netting, has been shown to be effective and can contribute to a successful integrated vector management (IVM) plan in the field to reduce this risk. However, other common US military field materials have not been evaluated with residual pesticides. In this study we conducted the first known investigation of the efficacy and longevity of a residual pesticide containing λ-cyhalothrin applied to HESCO® blast protection wall geotextile. We exposed treated material to a temperate Florida environment and found that this treatment can be effective against sand flies, filth-breeding flies, and mosquitoes for at least 6 wk. This study provides evidence that residual treatment of this US military material may be leveraged as an IVM component to enhance the US Department of Defense pest management system.
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Mousa, Elsayed. "Modern blast furnace ironmaking technology: potentials to meet the demand of high hot metal production and lower energy consumption". Metallurgical and Materials Engineering 25, nr 2 (2.07.2019): 69–104. http://dx.doi.org/10.30544/414.
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Iron and steel making is one of the most intense energy consuming in the industrial sectors. The intensive utilization of fossil carbon in the ironmaking blast furnace (BF) is related directly to CO2 emission and global warming. Lowering the energy consumption and CO2 emission from BF comes on the top priorities from both economic and environmental aspects. The BF has undergone tremendous modifications and development to increase production and improve the overall efficiency. Both technological development and scientific research drive one another to reach optimum operation conditions, which are very close to the ideal conditions; however, further development is still required to meet the stringent environmental regulations. The present article provides a comprehensive review of recent research and development which were carried out in modern blast furnace to increase the productivity meanwhile reduce the energy consumption and CO2 emission to meet the demand of steel market and the environmental protection. The recent technological and metallurgical improvements in the BF are intensively discussed including: (i) modifications of BF design, top charging and measuring system, (ii) upgrading of conventional top charging burden and alternative agglomerates, (iii) developing of tuyeres injection system and injected materials, and (iv) potentials of waste heat recovery and usage. These topics are reviewed and discussed in some details to elucidate the potential of recent progress in BF technology in saving the energy consumption and lowering CO2 emission. In this paper, the major research and development which have been carried out in ironmaking BF technology are reviewed with an overview of the future prospects.
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Altenaiji, Mohamed, Graham K. Schleyer i Yo Yang Zhao. "Characterisation of Aluminium Matrix Syntactic Foams under Static and Dynamic Loading". Applied Mechanics and Materials 82 (lipiec 2011): 142–47. http://dx.doi.org/10.4028/www.scientific.net/amm.82.142.
Pełny tekst źródłaStreszczenie:
Development of a lightweight, strong and energy-absorbing material that has potential application for the protection of vehicles and occupants against impact and blast, is a difficult challenge facing the materials community. Aluminium matrix syntactic foams will be investigated as a possible core material as part of a multi-layered protection system for military vehicles. Aluminium matrix syntactic foams are composite materials consisting of an aluminium matrix implanted with hollow or porous ceramic particles. This paper investigates the mechanical properties of aluminium matrix syntactic foam with different sizes of ceramic micro-spheres and different grades of aluminium, fabricated by the pressure infiltration method. The static crushing behaviour of the foam was investigated under two test conditions using an Instron 4505 machine. Results are compared and discussed. The dynamic compressive response was investigated using a drop-weight impact test machine. It was found that the particle size of the ceramic micro-spheres and the grade of the aluminium metal have a significant effect on the energy absorption capacity of the material. The compressive strength of the syntactic foam was found to increase with increasing compressive strength of the metal matrix.
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Moreb, J., J. R. Zucali, M. A. Gross i R. S. Weiner. "Protective effects of IL-1 on human hematopoietic progenitor cells treated in vitro with 4-hydroperoxycyclophosphamide." Journal of Immunology 142, nr 6 (15.03.1989): 1937–42. http://dx.doi.org/10.4049/jimmunol.142.6.1937.
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Abstract Based on recently published data, IL-1 has been shown to provide radioprotective effects when given to mice 20 h before a lethal dose of irradiation and to enhance granulocyte recovery in mice treated with cyclophosphamide. In this study, we have investigated whether IL-1 can provide protection for human bone marrow colony-forming cells treated with high doses of 4-hydroperoxycyclophosphamide (4-HC), a potent derivative of cyclophosphamide. We have established an in vitro model system which demonstrates that prior incubation with IL-1 protects early human hematopoietic progenitor cells from the lethal effects of high doses of 4-HC. These early progenitors give rise to blast cell colonies which appear late in the culture and are characterized by their ability to give rise to different types of secondary colonies when replated. Furthermore, prior incubation with IL-1 was shown not to protect HL-60 or K562 leukemic cells from the lethal effects of 4-HC. We conclude that IL-1 is able to protect early human hematopoietic progenitors from a non-cell cycle-specific chemotherapeutic agent such as 4-HC, whereas providing no protection for the leukemic cell lines HL-60 and K562.
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Adrianovsky, V. I., E. A. Kuzmina, N. V. Zlygosteva, A. P. Boyarsky i G. Ya Lipatov. "A SYSTEM APPROACH TO CARCINOGENIC RISK ASSESSMENT AND MANAGEMENT FOR METALLURGICAL WORKERS EMPLOYED IN VARIOUS BLISTER COPPER PRODUCTION PROCESSES". Hygiene and sanitation 96, nr 12 (27.03.2019): 1161–66. http://dx.doi.org/10.18821/0016-9900-2017-96-12-1161-1166.
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The paper presents results of the application of the system approach to carcinogenic risk assessment and management based on the identification carcinogens, prediction carcinogenic effects and rationale for targeted preventive and curative measures. Evidence from metallurgical shops where various blister copper production processes are used regardless of the existing smelting technologies shows the risk of cancer to be Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeingeptable even when the working conditions are classified as permissible (class 2) in terms of chemical factors. The highest carcinogenic risk values are observed for occupations with workplaces characterized by a significant release of dust, arsenic being the main risk contributor. In cases of the blast furnace and reverberatory furnace smelting, carcinogenic risks for workers with a 25-year length of employment exceed the permissible level by 17.6 and 28.8 times, respectively, and in the case of bath smelting, carcinogenic risks exceed the permissible level by 5.1 times. The maximum length of employment for bath smelting shop workers amounts to 5.14 years, being by 1.42 and 0.89 years higher than that for the blast furnace and reverberatory furnace smelting shop workers, respectively. The observed cancer mortality rates exceed significantly the expected mortality rates for the tumor of all sites in cases of combined and respiratory cancers. The highest cancer mortality rates were recorded for batch loaders (60%) and smelter (40%) with the highest predicted carcinogenic risk values. Cancer-specific marker levels higher normal ones were detected in 73% of workers from the increased individual carcinogenic risk group. The proposed system approach to carcinogenic risk assessment and management will make it possible to try out components of the risk-based approach in the supervisory activities at industrial facilities with exposure to carcinogens, to establish the acceptable risk levels depending on the length of employment, identify the priority carcinogens; it will also allow indicating a rationale for additional testing for occupational carcinogenesis predictors as part of routine medical examination procedures and to develop preventive measures against key risk factors.
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Kalidoss, Karthik. "CRISPR-Cas Genome Editing Tool: Mechanisms of Pathogen Resistance Plants – Review". Journal of Horticulture and Plant Research 7 (sierpień 2019): 69–80. http://dx.doi.org/10.18052/www.scipress.com/jhpr.7.69.
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In recent years, the CRISPR-Cas system is most familiar and advance genome editing tool in modern biological research. The genome editing tool used in various biological researchers worldwide in past years has witnessed exposure site-directed mutagenesis modification methods zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), Meganucleases and CRISPR-Cas9(associated proteins 9). CRISPR-Cas genome editing technology to ease design and implement, more flexible and less expensive. Plants are affected two types of stresses like biotic and abiotic. Abiotic occurs naturally temperature or wind, sunlight depend upon on the environmental conditions. Biotic stress is caused by pathogens of virus, fungi, bacteria, etc. This review to focus on the recent advance of plant protection use CRISPR-Cas system mechanism of disease resistant plants in past and current trends of research. A short overview of the experimental methodology for Beet Curly Top Virus (BCTV) disease and Magnaporthe oryzae fungus infection cause rice blast disease resistance mechanisms will be discussed. Furthermore, the need developments of this genome editing tool in future.
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Yang, Guoliang, Wenjia Huang i Shuai Feng. "Antiexplosion Performance of Engineered Cementitious Composite Explosion-Proof Wall". Advances in Materials Science and Engineering 2020 (20.03.2020): 1–10. http://dx.doi.org/10.1155/2020/1921960.
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The antiexplosion performance of an explosion-proof wall made of engineered cementitious composite was studied, using small-scale explosion-proof walls made of different materials and sizes that were subjected to on-site blasting. The dynamic responses of these walls were evaluated under blast loading using overpressure test system, digital image correlation (DIC) full-field strain testing, and high-speed photography recording of the crushing process. Analysis of the results of the overpressure and strain tests revealed the effect of the wall height on the overpressure behind the wall. Increasing the height of the explosion-proof wall can improve the protection ratio of the wall by more than 2%. The variation of full-field strain of different materials at the same burst ratio was obtained. The engineered cementitious composite explosion-proof wall was obviously superior to that of ordinary concrete in strain control on the back-explosion surface. These theoretical results provide references for the design of explosion-proof walls.
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Shrivastava, V. K., M. K. Pradhan, S. Minz i M. P. Thakur. "RICE PLANT DISEASE CLASSIFICATION USING TRANSFER LEARNING OF DEEP CONVOLUTION NEURAL NETWORK". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W6 (26.07.2019): 631–35. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w6-631-2019.
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<p><strong>Abstract.</strong> Early and accurate diagnosis of plant diseases is a vital step in the crop protection system. In traditional practices, identification is performed either by visual observation or by testing in laboratory. The visual observation requires expertise and it may vary subject to an individual which may lead to an error while the laboratory test is time consuming and may not be able to provide the results in time. To overcome these issues, image based machine learning approach to detect and classify plant diseases has been presented in literature. We have focused specifically on rice plant (<i>Oryza sativa</i>) disease in this paper. The images of the diseased symptoms in leaves and stems have been captured from the rice field. We have collected a total of 619 rice plant diseased images from the real field condition belong to four classes:(a) Rice Blast (RB), (b) Bacterial Leaf Blight (BLB), (c) Sheat Blight (SB) and (d) Healthy Leave (HL). We have used a pre-trained deep convolutional neural network(CNN) as a feature extractor and Support Vector Machine (SVM) as a classifier. We have obtained encouraging results. The early identification of rice diseases by this approach could be used as a preventive measure well as an early warning system. Further, it could be extended to develop a rice plant disease identification system on real agriculture field.</p>
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Si, Jianfeng, Dongwang Zhong i Wei Xiong. "Piezoceramic-Based Damage Monitoring of Concrete Structure for Underwater Blasting". Sensors 20, nr 6 (17.03.2020): 1672. http://dx.doi.org/10.3390/s20061672.
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This paper developed a piezoelectric-transducer-based damage detection of concrete materials after blasting. Two specimens (with or without an energy-relieving structure) were subjected to a 40 m deep-underwater blasting load in an underwater-explosion vessel, and their damage was detected by a multifunctional piezoelectric-signal-monitoring and -analysis system before and after the explosion. Statistical-data analysis of the piezoelectric signals revealed four zones: crushing, fracture, damage, and safe zones. The signal energy was analyzed and calculated by wavelet-packet analysis, and the blasting-damage index was obtained after the concrete specimen was subjected to the impact load of the underwater explosion. The damage of the two specimens gradually decreased from the blast hole to the bottom of the specimen. The damage index of the specimen with the energy-relieving structure differed for the fracture area and the damage area, and the damage protection of the energy-relieving structure was prominent at the bottom of the specimen. The piezoelectric-transducer-based damage monitoring of concrete materials is sensitive to underwater blasting, and with wavelet-packet-energy analysis, it can be used for postblasting damage detection and the evaluation of concrete materials.
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Naila Rafique. "Malakand Nizam-I-Adal Regulation 2009". sjesr 5, nr 3 (30.09.2022): 145–49. http://dx.doi.org/10.36902/sjesr-vol5-iss3-2022(145-149).
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The administration of Pakistan isn’t directly by Central Government, so that fail in administrative capacity. Malakand Division consists of Swat, Chitral, Dir, Malakand Agency. Before 1969 each states have had their own rule and regulations. After implementation of the PATA Regulation (Provincially Administrative Tribal Area) 1975, legal cases were decided by Tehsildar. Under PATA Regulation any person was arrested without any reason. So this Regulation was deteriorated Malakand situation. In 1994 imposition of Tehreek-i-Nifaz-i-Shariat-i-Muhammadi (TNSM), so it was called enforcement of Islamic law in Malakand Division[1]. This Regulation was later on repeal in 1999. The emergence of Tehreek-e-Taliban Pakistan (TTP) 2007 and was swallow up whole of FATA. The TTP has adopted modern techniques to subdue terrorism. Bomb blast and suicide attacks killed thousand of people in whole country. TTP attacked inside in Pakistan was revenge of US involvement in Afghanistan. So in this violence and conflict situation another Regulation was enforced in Malakand Nizam-e-Adal Regulation 2009. In this regulation disputes are settle by informal institutions. It is ensuring of natural justice system, equality, peace and protection.
[1] Sultan-i-Rome, Swat State, p. 308.
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Khobotova, Elina, i Vit, Datsenko. "Radioactivity of metallurgical enterprises waste". Bulletin of Kharkov National Automobile and Highway University, nr 100 (7.04.2023): 63. http://dx.doi.org/10.30977/bul.2219-5548.2023.100.0.63.
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Abstract. Problem. The problem of obtaining environmentally friendly materials is especially relevant when using the wastes that concentrate natural radionuclides (NRN) dangerous for public health. The concentrators of radionuclides include dump and granular blast-furnace slags. Goal. The purpose of the work is to determine the radionuclide composition of the fractions of dump and granular blast-furnace slags from Ukrainian enterprises, their compliance with the radiation safety standards of Ukraine and international radiological indicators, and to identify the factors that determine the level of natural radioactivity of the slags. Methodology. The specific activity of natural slag radionuclides was determined by the gamma spectrometric method on a SEG-001 scintillation gamma spectrometer. The mineral composition of the crystalline component of the slag was determined using X-ray phase analysis performed on a Siemens D500 powder diffractometer. The elemental composition of blast furnace slag was determined by the method of electron-probe microanalysis on a JSM-6390 LV scanning electron microscope with an INCA micro-X-ray analysis system. The particle charge and electrokinetic potential were determined during macroelectrophoresis of suspensions. Results. The blast-furnace slag contains natural radionuclides: 226Ra, 232Th and 40K. The content of radionuclides varies by waste fractions. According to the contribution to the total activity value, NRN can be arranged in a row: 40К > 226Ra > 232Th. The most radiation-clear is the fraction > 20 mm of the “Zaporizhstal” dump slag, the radioactivity of the fractions 1.25‒2.5 mm for DMC, 5‒10 and 0.63‒1.25 for MMC and the “ArcelorMittal” granulated slag is increased. All investigated slags belong to the first class of radiation hazard (Сef 370 Bq/kg) and can be used in construction without restrictions. Originality. All investigated slags correspond to international radiological indicators: Raeq 370 Bq/kg, radiation hazard indices are Iγ, Iex, Iin and Iα 1, which indicates that there is no danger of increased gamma radiation and emanation of radon and the daughter products of its decay into the room air. The concentration of radon indoors does not exceed 200 Bq/m3. For the average sample and slag fractions <2.5 mm of “ArcelorMittal”, the activity utilization index which determines the safety of practical waste use is overestimated; the absorbed dose rate in the open air and the annual effective equivalent dose are higher than the world average values, they are, respectively, 58 nGy/h and 0.07 mSv, but at the same time below the value recommended by the IAEA for the population of 1 mSv/year. The excess lifetime carcinogenic risk for dispersed fractions of “ArcelorMittal” slag is higher than the world average: 0.29·10–3, but below the 0.05 limit set by the International Commission on Radiation Protection. A direct correlation between the acidity of the slag fractions and the increase in radiological parameters was determined. Practical value. An attempt has been made to relate the radioactivity of blast-furnace slag with the NRN sorption on the negatively charged surface of slag particles, which is more reliable for amorphous sorption-active granular slag.
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García-Montelongo, Ana María, Amelia C. Montoya-Martínez, Pamela Helue Morales-Sandoval, Fannie Isela Parra-Cota i Sergio de los Santos-Villalobos. "Beneficial Microorganisms as a Sustainable Alternative for Mitigating Biotic Stresses in Crops". Stresses 3, nr 1 (15.01.2023): 210–28. http://dx.doi.org/10.3390/stresses3010016.
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Nowadays, population growth, the global temperature increase, and the appearance of emerging diseases in important crops generate uncertainty regarding world food security. The use of agrochemicals has been the “go-to” solution for the control of phytopathogenic microorganisms, such as Magnaporte oryzae, causing blast disease in rice and other cereals; Botrytis cinerea, causing gray mold in over 500 plant species; and Puccinia spp., causing rust in cereals. However, their excessive use has harmed human health, as well as ecosystems (contaminating water, and contributing to soil degradation); besides, phytopathogens can develop resistance to them. The inoculation of plant growth-promoting microorganisms (PGPMs) to crops is a sustainable strategy for increasing the yield and quality of crops and mitigating biotic stresses. Likewise, PGPMs, such as Pseudomonas, Bacillus, and Trichoderma, can trigger a series of signals and reactions in the plant that lead to the induction of systemic resistance, a mechanism by which plants react to microorganism stimulation by activating their defense system, resulting in protection against future pathogen attack. These plant defense mechanisms help to mitigate biotic stresses that threaten global food security. Thus, the study of these mechanisms at molecular, transcriptomic, and metabolomic levels is indispensable to elucidate how stresses affect globally important crops.
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Forte, Dorian, María García-Fernández, Abel Sánchez-Aguilera, Vaya Stavropoulou, Claire Fielding, Daniel Martín-Pérez, Alexandar Tzankov, Juerg Schwaller i Simón Méndez-Ferrer. "Leukemic Stem Cells Co-Opt Normal Bone Marrow Niches As a Source of Energy and Antioxidant Defence". Blood 130, Suppl_1 (7.12.2017): 94. http://dx.doi.org/10.1182/blood.v130.suppl_1.94.94.
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Abstract Modulation of oxidative stress as well as metabolic adjustments are key aspects in cancer stem cell-derived diseases, such as acute myelogenous leukemia (AML). Metabolic reprogramming in leukemia seems to be influenced by the crosstalk of malignant cells with their surrounding microenvironment. Reactive oxygen species (ROS), mainly generated by the mitochondria, are relatively high in malignant cells, without reaching a cytotoxic level that would compromise their survival. In addition, chemotherapy efficacy lies on increased ROS-mediated cellular damage. Cumulative evidence shows that AML often exhibits poor response to chemotherapy partly due to the support of leukemic stem cells (LSCs) by the bone marrow (BM) microenvironment, which includes BM mesenchymal stem cells (BMSCs). However, how exactly this happens, i.e. the specific mechanism(s) and cell populations implicated, remains incompletely understood. Hematopoietic stem cell (HSC)-niche forming BMSCs can be identified by the expression of the intermediate filament protein nestin and can be isolated and propagated as non-adherent 'mesenspheres', which can self-renew and support HSCs ex vivo. Here we have studied the contribution of nestin+ BMSCs to MLL-AF9-driven AML development and resistance. Immunohistochemistry for nestin on BM samples from AML patients (N=35) showed that the number of nestin+ niches per square millimeter was 2.4-fold higher as compared to control samples (N=12). To study the role of BMSCs in AML, we used a doxycycline-inducible iMLL-AF9 mouse strain that closely mimics the human disease (Stavropoulou V et al., Cancer Cell 2016;30:43-58). Development of AML in iMLL-AF9 mice caused a significant reduction of stromal cells in the BM but it did not reduce the number of BM nestin+ cells. To study the possible contribution of nestin+ cells to leukemia development, we partially depleted nestin+ cells by inducing diphtheria toxin expression in these cells using Nestin-creERT2 ; iDTA mice previously transplanted in a competitive fashion with pre-leukemic and normal BM cells. Nestin+ cell depletion selectively diminished leukemia burden in BM, spleen and blood, and reduced the number of primitive leukemic cells, without affecting normal residual hematopoiesis. Combined nestin+ cell depletion and standard chemotherapy further exaggerated the elimination of BM leukemic cells, suggesting that nestin+ cells contribute to chemotherapy resistance. To investigate the crosstalk of BMSCs and leukemic blasts, we developed a novel in vitro co-culture system using BM mesenspheres and iMLL-AF9+ leukemic blasts. Co-cultures with nestin+ mesenspheres promoted leukemic blast survival under metabolic stress (FBS deprivation) and chemotherapy (cytarabine, Ara-C). Increased survival correlated with a strong protection against excessive ROS levels and lipid peroxidation. Particularly, reduced glutathione (GSH), a key antioxidant element, increased in leukemic blasts co-cultured with nestin+ mesenspheres. Mitochondrial transfer from BMSCs has also recently been proposed as a metabolic-related mechanism contributing to chemoresistance in AML (Moschoi R et al. Blood 2016;128:253-64). Using the Seahorse Extracellular Flux Analyzer, we actually revealed that leukemic blast bioenergetics increased in co-culture with mesenspheres. Surprisingly, we found that chemotherapy-induced transfer of mitochondria from BMSCs to AML cells correlated with decreased ROS levels in the leukemic blasts, pointing out mitochondria transfer as an important ROS detoxifying mechanism to allow chemoresistance. We demonstrated that cell-to-cell contact could be required for Ara-C-mediated protective effects of mesenspheres on leukemic blasts and their mitochondria transfer. Accordingly, either the inhibition of GSH generation or mitochondrial transfer (by avoiding cell contact) may reduce BMSCs survival support after chemotherapy. Altogether, these results suggest that simultaneous co-opting of energy sources and anti-oxidant mechanisms of BMSCs contribute to chemoresistance in AML. Disclosures No relevant conflicts of interest to declare.
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Mahardika, Ketut, i Indah Mastuti. "THE EFFECTS OF CRUDE RECOMBINANT VIRAL PROTEIN VACCINES AGAINST GROUPER SLEEPY DISEASE IRIDOVIRUS (GSDIV) ON HUMPBACK GROUPER (Cromileptes altivelis)". Indonesian Aquaculture Journal 10, nr 2 (31.12.2015): 163. http://dx.doi.org/10.15578/iaj.10.2.2015.163-172.
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Infection of Megalocytivirus cause serious mass mortality in marine fish in South East Asian countries. The aim of this study was to produce recombinant of GSDIV capsid protein and its protection to humpback grouper Cromileptes altivelis against grouper sleepy disease iridovirus (GSDIV). A major capsid protein (MCP) was selected for use as a crude subunit vaccines. This gene target (MCP) was inserted to the protein expression system vector of pET SUMO and cloned in cells bacteria Escherichia coli strain BL-21. The MCP was succeded to be induced using 1 mM of IPTG. Results of protein analysis using MALDI TOF-TOF indicated that the MCP has measurement of 49.566 kDa with PI index of 6.00, and contained 453 amino acids. BLAST homology analysis exhibited that the amino acid sequence of the MCP showed high similarity with MCP of Red Sea Bream Iridovirus (RSIV). E. coli expressing MCP protein was inactivated using 0.03% formalin overnight and washed using PBS. The inactivated E. coli as a crude subunit vaccine was then injected intramuscularly to humpback grouper juveniles. Subsequently, the juveniles were challenged tested with GSDIV. The juveniles vaccinated with the MCP recombinant bacteria showed significantly higher survival rates than control those vaccinated with PBS. Thus, the MCP fusion protein is considered as a potential vaccine against GSDIV infections in grouper.
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Ramirez, Pablo A., Patricia Macanas, Leonardo Navarrete, Thomas Quezada, Richard Broekhuisen i Bruno Nervi. "The MCP-1/CCR2 Axis in the Biology of Acute Myeloid Leukemia: Possible Role in Blast Cell Migration". Blood 120, nr 21 (16.11.2012): 1439. http://dx.doi.org/10.1182/blood.v120.21.1439.1439.
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Abstract Abstract 1439 Background: Acute myeloid leukemia (AML) is a complex disease with a high mortality rate despite chemotherapy and allogeneic stem cell transplantation. There are multiple mechanisms of resistance against chemotherapy and significant data indicate that both CXCR4/SDF-1 and VLA-4/VCAM1 axes are involved in leukemia protection. Little is known about the role of MCP-1/CCR2 in AML biology and protection against chemotherapy. Methods: To evaluate the role of MCP-1/CCR2 in AML biology, we first measured MCP-1/CCR2 expression in AML cell lines and primary AML cells. We quantified CCR2 by flow cytometry (FCM), real time PCR (RT-PCR) and western blot (WB). MCP-1 production was quantified by solid phase ELISA in peripheral blood (PB) and bone marrow (BM) serum. Our second objective was to establish the role of MCP-1/CCR2 axis in chemotaxis, cell cycle and AML proliferation. Chemotaxis was performed in a 5um transwell system with AML primary cells (6×105 cells) or AML cell lines (2×105 cells) in the upper chamber and different concentrations of MCP-1/CCR2 agonists/blockers or controls added to the lower chamber. Migrated cells were measured by optic microscopy and FCM 24 hrs after culture. Cell cycle and proliferation experiments were performed as with the chemotaxis studies. Quantification of cell cycle and proliferation was done with BrDU by FCM. We also quantified cell cycle using propidium iodide and proliferation with yellow tetrazolium MTT. Our third objective was to determine if synergy was present in cell apoptosis in vitro when conventional chemotherapy and MCP-1/CCR2 blockade was combined. AML cells were cultured in the presence of rhMCP-1, CCR2 inhibitors or controls at different doses and IC50 cytarabine. Apoptosis was measured by FCM against Annexin V. Results: Of 34 patients, 18 (53%) expressed CCR2 by FCM. Mean CCR2 expression was 19% (range, 4–53) in PB and 20% (range, 6–63) in BM. We also screened 5 AML cell lines (Kasumi, GDM, THP-1, U937 and a murine AML), 2 of them expressing high levels of CCR2 (THP-1 and murine AML). RT-PCR in AML primary cells and CCR2+ cell lines confirmed mRNA production in these samples. WB analysis confirmed RT-PCR findings. MCP-1 solid phase ELISA analysis in PB and BM serum samples showed significantly lower levels of MCP-1 compared to normal controls (p<0.05). No differences were seen between BM and PB MCP-1 plasma levels (p=NS). Chemotaxis experiments confirmed functional activity of the axis in cell lines and primary cells with receptor expression. Overall, both AML primary cells and cell lines (U937, Kasumi, GDM) that lacked CCR2 expression, failed to transmigrate under different MCP-1 concentrations. In contrast, a dose-dependent migration was seen in AML primary cells expressing CCR2 and THP-1 cells, with a maximum effect using MCP-1 10ng/ml (5-fold increase over control). SDF-1 used as a positive control showed 2-fold increased migration over controls. A significant inhibition of transmigration was seen after MCP-1/CCR2 blockade. Proliferation of AML cell lines expressing CCR2 was slightly increased (1.4-fold) compared to controls after incubation with MCP-1 100ng/ml. A non-significant increase in phase S THP-1 cells was seen after incubation with MCP-1 50ng/ml compared to control (64% vs 60%, respectively in S phase). A concomitant decrease of cells in G1 was also observed (controls 32% vs. MCP-1 50ng/ml 27%, in G1 phase). The chemotherapy studies did not show a protective effect of MCP-1 on cytarabine-induced apoptosis or synergy with chemotherapy after MCP-1/CCR2 blockade. Conclusions: MCP-1/CCR2 axis is expressed in the majority of AML blasts analyzed. The axis is involved in cell trafficking and proliferation but no in vitro chemotherapy protective effect was seen. We are now investigating the possibility that the main in vivo effect is related to cell migration and mobilization, which could be a potential target in the treatment of AML. Funded by Chilean Government Grant FONDECYT #1110319 Disclosures: No relevant conflicts of interest to declare.
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Пласкеева, Е. И., Д. А. Полянская, В. И. Трусов, Р. С. Ходжаев i Г. В. Черкаев. "Atmospheric resistance coating systems for shipboard yard". MORSKIE INTELLEKTUAL`NYE TEHNOLOGII), nr 1(51) (5.03.2021): 75–78. http://dx.doi.org/10.37220/mit.2021.51.1.028.
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Предметом исследования является фосфатирующий состав «НОТЕХ». Это цинкфосфатный водный материал с неорганическими ингибиторами коррозии анодного типа, которые эффективно подавляют развитие подпленочной коррозии под слоем грунта. Механизм действия и исследования эффективности подавления коррозии фосфатирующего состава «НОТЕХ» проводилась с отечественными лакокрасочными материалами типа грунта ЭФ-065 и эмали ЭП-1236. Цель работы – обоснование системы покрытия с химической подготовкой поверхности под окраску. Предложена универсальная атмосферостойкая система лакокрасочного покрытия повышенной надежности и долговечности для защиты береговых металлических сооружений, конструкций и оборудования судостроительной верфи. Впервые методами кондуктометрии, рН-метрии и измерения адгезии показана совместимость «НОТЕХ» с алкидным грунтом Pilot QD Primer компании JOTUN и соответствие требованиям стандартов ISO по содержанию остаточных водорастворимых веществ перед окраской. При этом дополнительная обработка поверхности «НОТЕХ» после абразивоструйной очистки до степени Sa2,5 не ухудшает адгезию покрытия, а также допустима нестандартная операция преобразования продуктов вторичной (вспышечной) коррозии после очистки абразивом без их удаления. The subject of the study is the phosphating composition «НОТЕХ». It is a zinc phosphate aqueous material with inorganic anode-type corrosion inhibitors that effectively suppress the development of sub-film corrosion under a layer of soil. The mechanism of action and research on the effectiveness of corrosion suppression of the phosphating compound «НОТЕХ» was carried out with domestic paints and varnishes such as soil ЭФ-065 and enamel ЭП-1236. The purpose of the work is to substantiate a coating system with chemical surface preparation for painting. A universal weather-resistant paint and varnish coating system of increased reliability and durability for the protection of coastal metal structures, structures and equipment of a shipyard is proposed. For the first time, conductometry, pH and adhesion measurements have demonstrated the compatibility of «НОТЕХ» with JOTUN's Pilot QD Primer alkyd soil and compliance with ISO standards for residual water-soluble substances before painting. Moreover, additional processing of the «НОТЕХ» surface after abrasive blast cleaning to the degree of Sa2.5 does not impair the adhesion of the coating, and a non-standard operation of converting secondary (flash) corrosion products after abrasive cleaning without removing them is also acceptable.
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SHIRAK, A., LIOR DOR, E. SEROUSSI, M. RON, G. HULATA i D. GOLANI. "DNA BARCODING OF FISH SPECIES FROM THE MEDITERRANEAN COAST OF ISRAEL". Mediterranean Marine Science 17, nr 2 (16.05.2016): 459. http://dx.doi.org/10.12681/mms.1384.
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Accurately-classified genomic data in the Barcode of Life Data System (BOLD) database is vital to the protection and conservation of marine biodiversity in the Mediterranean Sea. The taxonomic classifications of 468 fish of 50 Mediterranean species were analyzed using the BOLD Identifier tool for variation in the cytochrome oxidase subunit I (COI) mitochondrial gene. Within species, nucleotide maximum composite likelihood was low with a mean of 0.0044±0.0008. Three presumptive species had significantly higher values e.g., Arnoglossus spp. (0.07), Torquigener flavimaculosus (0.013) and Boops boops (0.028). However, samples of Arnoglossus species were sub-classified into two groups that were finally identified as two different species e.g., Arnoglossus laterna and Arnoglossus thori. For the different species, BLAST searches against the BOLD database using our DNA barcoding data as the query sequences designated the most similar targets into groups. For each analyzed species, the similarity of the first and second threshold groups ranged from 95 to 99% and from 83 to 98%, respectively. Sequence based classification for the first threshold group was concordant with morphology-based identification. However, for 34 analyzed species (68%) overlaps of species between the two threshold groups hampered classification. Tree-based phylogeny analysis detected more than one cluster in the first threshold group for 22 out of 50 species, representing genetic subgroups and geographic origins. There was a tendency for higher conservation and lower number of clusters in the Lessepsian (Red Sea) migrant versus indigenous species.
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KOSAREV, Nikolay Petrovich, Vladimir Nikolaevich MAKAROV, Aleksandr Vladimirovich UGOL'NIKOV, Nikolay Vladimirovich MAKAROV i German Petrovich DYLDIN. "Mine aerology of dust aerosols under conditions of hydro-vortex coagulation". NEWS of the Ural State Mining University, nr 4 (20.12.2020): 155–65. http://dx.doi.org/10.21440/2307-2091-2020-4-155-165.
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Dust suppression is the most popular method for depositing dust from the air to blast isolation. Improving the isolation system for probable coal dust explosions is an integral part of the problem of dust explosion protection of mining enterprises, the solution of which is one of the most important tasks in the field of occupational safety and health. Purpose: study of physics of the process and the construction of a mathematical model of the movement of aerosols in mine workings in a wide range of changes in the inertial kinematic parameters of the air flow. Research methods. Based on the Boussinesq equation, the Fourier rule and the similarity theorem of complex systems, the analogy of vorticity dispersion and kinematic viscosity, a mathematical model of the movement of dust aerosols under hydro-vortex coagulation conditions is constructed. Some similarity criteria are obtained that ensure the identity of experimental studies and real aerological processes in mines, as well as criterion equations for calculating the coefficient of aerodynamic drag and the time of unsteady inertial motion. Results. Equations are obtained that make it possible to identify aerodynamic processes of aerosol motion under hydro-cyclonic dust suppression through the criteria of Reynolds, Euler and Archimedes, corresponding to the overStokes and Stokes flow regimes. The possibility of reducing the aerodynamic resistance to 20% during hydro-vortex coagulation has been confirmed, which makes it possible to increase the energy efficiency of dust suppression by up to 15% and to increase the turbulization coefficient by at least 20%, thereby reducing the likelihood of a hazardous concentration of dust aerosols. Application. The use of the proposed mathematical model will make it possible to better calculate local aerological processes in mine workings and, as a consequence, to increase the efficiency of turbulization and dust suppression process control at mining enterprises.
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Gorlov, Yu V., i N. L. Razumnyak. "COAL MINES BLAST PROTECTION WITH THE USE OF AUTOMATIC BLAST LOCALIZATION SYSTEMS". Occupational Safety in Industry, nr 9 (wrzesień 2018): 13–19. http://dx.doi.org/10.24000/0409-2961-2018-9-13-19.
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Tsymbal, V. P., I. A. Rybenko, P. A. Sechenov, V. I. Kozhemyachenko, S. N. Kalashnikov i L. A. Ermakova. "Theoretical matters of self-organization and their practical implementation in jet-emulsion metallurgical process. Part 1. Basic principles and design features of jet-emulsion facility". Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 77, nr 2 (25.02.2021): 151–58. http://dx.doi.org/10.32339/0135-5910-2021-2-151-158.
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At present in the world steel industry a certain number of processes of iron direct reduction created, including liquidphase ones, which make it possible to obtain metal iron directly from ore bypassing blast furnace. However, no one of them enables principally to obtain an iron-carbon alloy with carbon content lower 2%. A jet-emulsion metallurgical process elaborated, differing by low energy consumption, small specific volume of the facility and possibility of metal direct producing with a wide range of carbon content. Application of principles of self-organization theory and of several physical effects enabled to create a process, which has significant advantages comparing with existing metallurgical processes. High rates of physical and chemical processes are reached by creating a large reaction surface and two-phase working mixture (gas suspension or emulsion). Organization of forced motion of the working (reaction) mixture in a closed system under pressure made it possible to create considerable deviation from thermodynamic equilibrium and at the same time to solve the task of internal transportation of reaction products through all the units connected in series/ Creation of dissipative structures, considerably deviated from thermodynamic equilibrium, ensures wide possibilities to control the chemical composition of metal and slag. A technological diagram and a brief description of the jet-emulsion facility (JER). The base of the JER technological scheme make the following units: charge supply system, reactor-oscillator, connecting channel with gas-dynamic self-shutting, refining sediment box, at the same time operating as the first stage of wet gas-cleaning, as well as automated system of scull cooling. The latter enables to ensure viability of the facility, in which high-temperature gas suspension is moving with high speed. Because of high intensity of gas-dynamic processes of aggressive two-phase media taking place in the facility, the protection of all the elements of the facility is made based on circulating scull cooling.
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Kunkle, Carey A., i Michael P. Schmitt. "Analysis of a DtxR-Regulated Iron Transport and Siderophore Biosynthesis Gene Cluster in Corynebacterium diphtheriae". Journal of Bacteriology 187, nr 2 (15.01.2005): 422–33. http://dx.doi.org/10.1128/jb.187.2.422-433.2005.
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ABSTRACT This report describes a genetic locus associated with siderophore biosynthesis and transport in Corynebacterium diphtheriae. A BLAST search of the C. diphtheriae genome identified a seven-gene cluster that included four genes, designated ciuA, ciuB, ciuC, and ciuD, whose predicted products are related to ABC-type iron transporters. Downstream from ciuD is the ciuE gene, whose predicted product is similar to the aerobactin biosynthetic enzymes IucA and IucC. The CiuE protein, which has a predicted mass of 121,582 Da and is approximately twice the size of either IucC or IucA, is homologous to each of these proteins in both its N- and C-terminal regions. C. diphtheriae ciuE deletion mutants exhibited a defect in siderophore production, iron uptake, and growth in low-iron medium. Mutations in the ciuA gene, whose predicted product is a lipoprotein component of an iron transport system, resulted in a severe defect in iron uptake and reduced ability to use the C. diphtheriae siderophore as an iron source. Site-directed mutations in irp6A, a gene previously reported to be associated with siderophore transport, had no effect on iron uptake or the utilization of the C. diphtheriae siderophore as an iron source. Transcriptional analysis demonstrated that expression of ciuA and ciuE is DtxR and iron regulated, and DNase I protection experiments confirmed the presence of DtxR binding sites upstream from each of these genes. Thus, this iron- and DtxR-regulated gene cluster is involved in the synthesis and transport of the C. diphtheriae siderophore.
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Zhang, Kai, Haifeng Lu, Jie Li i Hao Bai. "Orthogonal Experimental Study on the Factors Affecting the Mechanical Properties of Alkali-Activated Slag Materials". Materials 15, nr 24 (9.12.2022): 8795. http://dx.doi.org/10.3390/ma15248795.
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Blast furnace slag is one of the largest solid wastes in the world. The slag-based geopolymer obtained by alkali activation has many advantages, such as a high strength, a good corrosion resistance, low carbon and environmental protection. Existing studies have shown that the mechanical properties of slag-based geopolymers are related to the combined effects of many factors, but there is still a lack of reliable conclusions on the primary and secondary influence degree of each factor, which greatly affects the scientific preparation and application of slag-based geopolymers. In order to solve this problem, we choose to proceed from the two perspectives of the mix ratio of the alkali activator and the elemental composition of raw materials. Through the orthogonal analysis method, this paper studies the influence of the modulus of the alkali activator, the solid-to-liquid ratio of the activator, the water–cement ratio and the metakaolin replacement rate on the uniaxial compressive strength of a slag-based geopolymer. The results show that when the solid–liquid ratio is about 0.25, the modulus of the alkali activator is 1.3~1.5, the water–cement ratio is about 0.4 and the samples with higher strength can be prepared. With the addition of metakaolin, a new gel phase NASH was formed in the system, which significantly promoted the late strength and toughness growth of the sample. The research results comprehensively analyze the influence of different factors on the mechanical properties of the slag-based geopolymer, which can provide a valuable reference for the engineering application of alkali-activated slag materials.