Indirect Fire Research Articles

Origin of archaeological black bones within a waterlogged context: A multidisciplinary approach

This paper presents the interdisciplinary study on the origin of “black bones” at the Neolithic lakeside settlement of Dispilio, Greece (5500–3500 BCE), where animal bones have been recovered from a waterlogged and organic soil-matrix containing charcoal, ash and burnt cultural remains. In the past, this has been interpreted as the result of the destruction of the village by fire and abandonment. This study aims to examine this theory through the distinction of burnt vs. oxide stained bones.A selection of 44 fish and 19 mammal bone samples are examined through Optical Microscopy, Scanning Electron Microscopy (SEM), X-ray Microanalysis (EDS), X-ray Diffraction (XRD) - Rietveld Analysis, Infrared Spectroscopy (ATR, NIR) and chemical analyses (ICP-MS).Alterations of histology, mineralogy, chemistry, crystallinity and structural parameters prove that the “black” bones from Dispilio owe their colour to Mn and Fe oxide staining. Light-coloured bones found at the site, have not been affected by this diagenetic procedure, which suggests that they were buried in a totally different geochemical environment.The analytical techniques employed did not offer any proof that the studied material is burnt. However, due to the fact that most techniques used to this day allow for the identification of thermal alteration of bone at temperatures usually higher than 300-450 °C, the possibility of thermal alterations due to an indirect fire, thus at lower temperatures or a fire of small duration cannot be identified and thus be ruled out.

Numerical comparative investigation of a flexible lignite-fired boiler using pre-dried lignite or biomass as supporting fuel

This work presents a numerical parametric investigation of an indirect firing scheme for a lignite-fired boiler during its operation at a thermal load of 35% of the nominal one, lower than the current technical minimum. The parametric investigation is important in order to evaluate different configurations of the firing concept and the impact of two different types of supporting fuels: pre-dried lignite and exhausted olive cake. Numerical results indicate that both types of supporting fuel can ensure the stable operation of the boiler at the reduced operating load. Moreover, it can be remarked, that the injection of biomass as supporting fuel improves the thermal efficiency of the boiler. Furthermore, the firing system setup especially for the injection of pre-dried lignite affects significantly the NOx emissions due to the developed temperature field. Finally, simulation results indicate that the injection of biomass particles through all vapour burners induces high thermal loading on boiler surfaces. Therefore, it is proved that the firing strategy plays a key role to the operation of a boiler using these fuel blends.

Retrofitting of different types of reinforced concrete beams after exposed to elevated temperature

The development of the concrete industry has facilitated the use of nonconventional concrete types, such as high-strength concrete (HSC) and self-compacting concrete (SCC). Normal concrete (NC) beams experience a significant reduction in their strength after fire exposure. An experimental program is designed to investigate the effect of different levels of temperature on the most common concrete types and the effect of different retrofitting techniques to restore the capacity of reinforced concrete beams. Thirty-one beams were casted using NC, SCC, and HSC. Twenty-eight beams were subjected to temperatures of 400 °C and 600 °C for 60 min and 120 min to evaluate the beam behaviour under indirect fire conditions. Carbon fibre reinforced polymer (CFRP) laminates, bonded steel plates, and concrete jacketing have been used for beam capacity retrofitting. The exposure time at a high temperature level had a significant effect on the behaviour of the different beams, especially those with NC, which underwent a dramatic reduction in strength after being subjected to 600 °C for 2 h. The SCC beams had an acceptable behaviour under elevated temperature conditions. All the retrofitting techniques had a positive effect on SCC and HSC beams, but the bonded steel plate and CFRP techniques did not produce a noticeable effect on NC at 600 °C. The reinforced concrete jacket had a satisfactory effect in the drastically deteriorated beams.

Using tanks for idirect fire - an attempt to reactivate training

Indirect fire is a domain of artillery. Tanks due to their combat capabilities (mobility, hit resistance and accuracy of fire) were hardly used for such type of tasks, although being prepared from constructional point of view. Nevertheless, evaluation of a concept of tanks utilization in a battlefield frequently oscillated around a support of infantry or just operation support. Closing down and ceasing development of artillery units as a result of the Polish Armed Forces’ transformation led to a situation under which the lack of an adequately intensive artillery fire significantly affecting support of first echelon units can be faced during real operations. For this reason, the General Command of Branches of Armed Forces bearing in mind tanks’ capability of fulfilling the aforementioned task decided to reactivate the competence of indirect fire by tanks’ crews, especially because the execution of this task was terminated at the beginning of the 1990s. The article presents the analysis of documents in force related to conducting indirect fire by a tank subunit and characteristics of individual undertakings required for preparation of a subunit to fulfil above-mentioned tasks based on the experience gained by a tank battalion of the 15th Mechanized Brigade in Giżycko, as well as realization of numerous organizational projects necessary for shooting preparation and fire control execution during fulfillment of this type of fire tasks. Results of practical indirect fire execution by tanks lead to constructive observations referred to achieving high results of an accurate indirect fire by tanks and implementing changes in documents which normalize training and shooting processes, adjusting an organizational portion of the project to the current organizational structures of tank and artillery subunits and to correlations resulting from this fact. The article also inclines to discussion regarding the direction of changes indispensable for conducting the indirect fire by tanks and the rationale of the execution of these tasks in a contemporary battlefield.

Seeing Things Differently: Nang, Tura, Zolm, and Other Cultural Factors in Taliban Attitudes to Drones

This article addresses the question of what the Taliban think about drones. Western literature on this question is predominately anti-war, anti-drone, or critical of the lack of transparency, which means little to the Taliban. The discussion here focuses on their literature, exploring it through the frames of how Pashtuns understand war and bravery in combat, how Pashtuns have created meta narratives to discuss the relationship between US and allied use of force and how that connects to a wider understanding of the legitimacy. This has important policy implications because the primacy that the drone has in the West as a totemic weapon of war does not exist for the Taliban. Their dislike of drones is indivisibly and culturally bound, not specific to the instrument as distinct from other means of aerial and indirect fire.

Using tanks for idirect fire - an attempt to reactivate training

Indirect fire is a domain of artillery. Tanks due to their combat capabilities (mobility, hit resistance and accuracy of fire) were hardly used for such type of tasks, although being prepared from constructional point of view. Nevertheless, evaluation of a concept of tanks utilization in a battlefield frequently oscillated around a support of infantry or just operation support. Closing down and ceasing development of artillery units as a result of the Polish Armed Forces’ transformation led to a situation under which the lack of an adequately intensive artillery fire significantly affecting support of first echelon units can be faced during real operations. For this reason, the General Command of Branches of Armed Forces bearing in mind tanks’ capability of fulfilling the aforementioned task decided to reactivate the competence of indirect fire by tanks’ crews, especially because the execution of this task was terminated at the beginning of the 1990s. The article presents the analysis of documents in force related to conducting indirect fire by a tank subunit and characteristics of individual undertakings required for preparation of a subunit to fulfil above-mentioned tasks based on the experience gained by a tank battalion of the 15th Mechanized Brigade in Giżycko, as well as realization of numerous organizational projects necessary for shooting preparation and fire control execution during fulfillment of this type of fire tasks. Results of practical indirect fire execution by tanks lead to constructive observations referred to achieving high results of an accurate indirect fire by tanks and implementing changes in documents which normalize training and shooting processes, adjusting an organizational portion of the project to the current organizational structures of tank and artillery subunits and to correlations resulting from this fact. The article also inclines to discussion regarding the direction of changes indispensable for conducting the indirect fire by tanks and the rationale of the execution of these tasks in a contemporary battlefield.

One million rounds fired in 12 hours? An analysis of the account of six guns of the 100th Brigade Machine Gun Company at High Wood in August 1916

ABSTRACTThe Great War saw machine gunnery develop from a direct fire weapon through to mass indirect fire barrages. There is an account from High Wood in August 1916 that represents the pinnacle of these developments – firing one million rounds from ten guns in 12 hours. This research examines that account to determine what happened and the technical and logistical requirements of such a feat. By examining the war diaries and characteristics of the Vickers machine gun, it has been possible to identify what actually took place, what would have been necessary for one million rounds to be fired, the potential of Great War machine gunnery and challenge posed when citing first-hand accounts from veterans.

Comparative investigation of a co-firing scheme in a lignite-fired boiler at very low thermal-load operation using either pre-dried lignite or biomass as supporting fuel

This work presents an investigation of an indirect firing scheme using biomass (cardoon) as supporting fuel for a pulverized-lignite boiler during its operation at a thermal load of 35%, lower than the current minimum one. Results are compared with an alternative indirect firing scheme which employs pre-dried lignite (PDL) as supporting fuel. The numerical investigation of the boiler has been conducted using the commercial software ANSYS Fluent® v15.0, supported by in-house built functions for the combustion rate of the fuels and the drag force exerted on biomass particles. The simulation and the comparison of the combustion of two different fuel blends in a co-firing strategy is important in order to evaluate technically the available possibilities and select among them the optimal firing concept (number and position of the operating injection ports) and the ideal fuel blend for the operation of the unit at lower than technical minimum thermal loads, in order to attain reduction of emissions and improvement of the boiler flexibility. Due to the implementation of a two-stage over-fire air (OFA) system and the consideration of sub-stoichiometric conditions exhibited at the nominal load, this work also takes into consideration the modeling of the boiler convective section, following the porous media analysis provided by the available Macro Heat Exchanger Model, ANSYS Fluent®. The validation of the applied models has been performed in previous works of the same group of authors, while the combustion results regarding crucial combustion parameters have been compared against corresponding values derived by a suitably-developed thermodynamic model. The agreement between these two models is good, since the maximum percentage deviation is calculated to be in the range of approximately 10%. Based on the numerical results, it can be concluded, that the utilization of both types of supporting fuel can ensure the stable operation of the boiler at thermal loads, lower than the technical minimum of the unit, promoting its flexibility. Between the two different supporting fuels, it is observed, that biomass ensures higher combustion efficiency compared to pre-dried lignite. However, it is also indicated, that the reduction of NOx emissions and the intensity of the induced thermal loading on the membrane walls with the utilization of biomass is more dependent on the firing strategy compared to lignite, proving the key role that this parameter plays to the operation of a boiler using this specific fuel blend.

British military mapping on the Western Front 1914–18

ABSTRACTCertain pointers to the possible direction military operations might take were available by 1914, notably the trench warfare, heavy artillery and siege operations of the Russo-Japanese War (1904–5), and the air and siege elements of the Balkan Wars (1912–13), and the air aspects of Italian operations in Libya (1911–12). Given the crucial importance of aerial photography and air survey to operations and mapping in the First World War, it is important to note that British survey and mapping on the Western Front developed from a starting point of almost total British lack of knowledge, equipment or experience for aerial photogrammetry. The Germans (and Austrians) and French were significantly ahead. Another initial weakness was the lack of provision for artillery survey. The Crimean War (1854–6) apart, the British Army had seen only colonial campaigns since Waterloo, and was ill-prepared for a long, continental campaign. The experience of the Boer War (1899–1902), however, had been invaluable in terms of the realisation of the need for indirect artillery fire, air observation (balloons, and latterly airships and aeroplanes) and rethinking survey and mapping requirements. After a slow start in 1914–16 (particularly with map reproduction plant in the field), the British rapidly adapted to the challenge of a new type of warfare, eventually creating a remarkably efficient field survey and mapping organisation which ended the war in a commanding position.

An experimental study on the effects of the use of multi-walled carbon nanotubes in ethylene glycol/water-based fluid with indirect heaters in gas pressure reducing stations

Heaters that work with indirect fire and water heating have a variety of applications, especially in the gas industry and in gas processing. In the present study, an experimental device is first constructed to enhance heat transfer in indirect heaters in gas pressure reducing stations in Iran, and then its efficiency is examined by adding multi-walled carbon nanotubes (MWCNTs) to ethylene glycol/water-based fluids. The efficiency of the experimental device was tested with MWCNTs at volume fractions of 0.025, 0.05, 0.1, 0.2 and 0.3 and diameters of 20–30 nm to enhance heat transfer. The results showed that the viscosity of the nanofluid was enhanced by increasing the volume fraction of their nanoparticles while an increase in the temperature reduces the viscosity and density of the nanofluid. Besides, the specific heat coefficient of the nanofluid is increased with temperature, but did not show significant changes with the increase in volume fraction. Increasing the volume fraction, however, increased the thermal conductivity coefficient and viscosity ratios, and increasing the Nusselt number also increased the convective heat transfer coefficient. Furthermore, results show a 34.5 °C increase in the outlet gas temperature difference and a 48% growth in efficiency at volume fraction of 0.05 and temperature of 70 °C. These findings are relatively consistent with the theoretical assumptions.

Influence of difference in surface tension on indirect fire suppression on fire extinguishing ability

Influence of difference in surface tension on indirect fire suppression on fire extinguishing ability

NOx reduction using advanced techniques in a 175MWth multi-fuel corner-fired boiler

The techniques used to reduce emissions in a typical coal boiler are well established, and projects concerning wall-fired, tangentially-fired and down-fired boilers have been widely published in literature. This article discusses a recent project concerning the reduction of NOx and unburnt losses through advanced primary measures in a Czech corner-fired furnace using swirl-stabilised burners, usually typically installed on wall fired units.The 200t/h boiler is part of a large steel manufacturing complex. The firing system has been designed to fire coking coal as the primary fuel, with blast furnace gas and coke oven gas as secondary fuels. Relying on an indirect firing system and a single mill while attempting to burn a suite of difficult fuels presents a number of challenges, especially when targeting high-performance combustion as required for IED compliant emissions performance.A site assessment and a baseline testing programme were performed to obtain detailed process data. The 2.2 fuel ratio coal proved to be difficult to burn, and resulted in baseline carbon-in-ash levels over 20%, with NOx emissions above 470mg/Nm3. The experimental results were replicated in computational fluid dynamics and used to calibrate the full-furnace combustion CFD model used to confirm the design of the final solution. Bespoke burners were designed and installed for each fuel and an advanced over fire air system was installed to allow heavy staging of the combustion air. Low NOx performance was achieved through a combination of the ultra-low NOx burner design and the use of vapour injection, which, in conjunction with an efficient overfire air system, allowed the plant to achieve a NOx reduction of up to 39%, while carbon-in-ash was reduced by up to 88%.

Climate change vulnerability assessment of forests in the Southwest USA

Climate change effects are already apparent in some Southwestern US forests and are expected to intensify in the coming decades, via direct (temperature, precipitation) and indirect (fire, pests, pathogens) stressors. We grouped Southwestern forests into ten major types to assess their climate exposure by 2070 using two global climate models (GCMs) and two emission scenarios representing wetter or drier conditions and current or lowered emission levels. We estimate future climate exposure over forests covering 370,144 km2 as the location and proportion of each type projected to experience climate conditions that fall outside 99% of those they currently occupy. By late century, 27–77% is climatically exposed under wetter or drier current emission levels, while lowered emission levels produce 10–50% exposure, respectively. This difference points to the benefits of reducing emissions from the RCP8.5 to the RCP4.5 track, with regard to forest retention. Exposed areas common to all four climate futures include central Arizona and the western slope of the Sierra Nevada. Vulnerability assessments also comprise sensitivity and adaptive capacity, which we scored subjectively by forest type according to the number of key stressors they are sensitive to and the resilience conferred by life history traits of their dominant tree species. Under the 2070 RCP8.5 emissions, four forest types are critically and six are highly vulnerable under the hotter GCM; and eight are highly and two moderately vulnerable under the wetter GCM. We discuss forest management adaptation strategies and the barriers to and co-benefits of such plans.

Extinguishing characteristics of a diffusion flame with water vapor produced from a water droplet impacting onto a heated plate

In this study, we have investigated an extinguishing method of a diffusion flame with water vapor produced from a water droplet impacting onto a headed plate, which is called as indirect fire attack. In order to clarify the extinguishing characteristics, the extinguishing experiments of a methane-air diffusion flame have been performed by using a pure water droplet with the diameter of 3.2mm. The droplet dropped from the height of 400mm. The wall superheat and the burner height were varied from 0K to 330K and from 32mm to 102mm, respectively. As a result, under certain wall-heat conditions, the water-vapor vortex ring is formed and visualized by the white water fog. At wall superheat of 150K, the formation probability of the vortex ring is unity and the extinguishing probability always shows the peak values regardless of the burner height. As a result, it can be said in our study that the wall superheat of 150K is the most effective value for the indirect extinguishing method.

Eficacia del Procedimiento de Tutela Laboral como protección contra el mobbing en Chile

The "constitutionalisation" of the labor law has allowed an advance in the protection of the fundamental rights inside the company, as much for the aplication between individuals of the fundamental rights, as for the progressive aparition of labor regulations that supports them. Even for the absence of regulation in the chilean legislation about the figure of mobbing or labor psychological abuse, the protection of the fundamental rights wich are involved in this contrariety, allows to configurare jurídica! ways to confront it. The typical juridic ways, before the labor procedure reformation, were limitated principal y to ordinary indemnization actions, the indirect firing or the protection action. The new labor procedure reformation instaurated wich it is the great way to confornt the mobbing, because contemplares the advances taken by the new doctrines about the protection of unspecified rigths. The current paper pretends to determinare if the use of this procedure will be efficient for the abused worker to regain the state before the abuse, qith the compensation for the damages wich he has been exposed.

Protective Structure Design against Airblast Effect

In the Army of the Czech Republic, the protective structure design is currently regulated by a military standard Žen 2-1/1, mainly for buried structures and against nuclear loads. As the nature of current armed conflicts suggests, it would be more appropriate to design above-ground protective structures exposed to the effects of direct or indirect fire weapons. The paper describes a search for an ideal above-ground structural shape exposed to an airblast. Several shapes were designed and their behavior under a typical airblast loading was tested using ANSYS software. As a result of the analysis, the most suitable shape of a protection structure was designed.

ARMED FORCES TODAY

ARMED FORCES TODAY

Minimizing civilian harm in populated areas: Lessons from examining ISAF and AMISOM policies

AbstractBoth the African Union Mission in Somalia (AMISOM) and the International Security Assistance Force (ISAF) – the North Atlantic Treaty Organization's security assistance mission to Afghanistan – have recognized the importance of reducing civilian harm, and adopted policies and practices that restrict the use of certain weapons in populated areas. ISAF commanders issued a number of tactical directives that restricted the use of certain air-delivered weapons, and AMISOM developed an indirect fire policy limiting the use of artillery and other indirect fire munitions in populated areas. This article examines both ISAF and AMISOM policies and practices to reduce civilian harm in populated areas and explores how these policies strengthened adherence to international humanitarian law and illustrated new ways in which armed actors can take feasible precautions and prioritize civilian protection.

Improved theory of generalized meteo-ballistic weighting factor functions and their use

Abstract It follows from the analysis of artillery fire errors that approximately two-thirds of the inaccuracy of indirect artillery fire is caused by inaccuracies in the determination of the meteo parameters included in fire error budget model. Trajectories calculated under non-standard conditions are considered to be perturbed. The tools utilized for the analysis of perturbed trajectories are weighting factor functions (WFFs) which are a special kind of sensitivity functions. WFFs are used for calculation of meteo ballistic elements µB (ballistic wind wB, density ρB, virtual temperature τB, pressure pB) as well. We have found that the existing theory of WFF calculation has several significant shortcomings. The aim of the article is to present a new, improved theory of generalized WFFs that eliminates the deficiencies found. Using this theory will improve methods for designing firing tables, fire control systems algorithms, and meteo message generation algorithms.

Synergy of direct and indirect cholinergic septo-hippocampal pathways coordinates firing in hippocampal networks.

The medial septum/diagonal band of Broca complex (MSDB) is a key structure that modulates hippocampal rhythmogenesis. Cholinergic neurons of the MSDB play a central role in generating and pacing theta-band oscillations in the hippocampal formation during exploration, novelty detection, and memory encoding. How precisely cholinergic neurons affect hippocampal network dynamics in vivo, however, has remained elusive. In this study, we show that stimulation of cholinergic MSDB neurons in urethane-anesthetized mice acts on hippocampal networks via two distinct pathways. A direct septo-hippocampal cholinergic projection causes increased firing of hippocampal inhibitory interneurons with concomitantly decreased firing of principal cells. In addition, cholinergic neurons recruit noncholinergic neurons within the MSDB. This indirect pathway is required for hippocampal theta synchronization. Activation of both pathways causes a reduction in pyramidal neuron firing and a more precise coupling to the theta oscillatory phase. These two anatomically and functionally distinct pathways are likely relevant for cholinergic control of encoding versus retrieval modes in the hippocampus.