Topic
Vapours
About: Vapours is a research topic. Over the lifetime, 1153 publications have been published within this topic receiving 15022 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this paper, the effect of the variation of the [ HC ] o [ NO 2 ] o ratio on the formed ozone, PAN, PPN and nitric acid was evaluated, and the results showed that the PAN produced from the unleaded vapours was much less than that of the leaded ones.
TL;DR: In this paper , an innovative technology was developed to quantify naturally emitted nitrogen oxides, NOx, from Nitrocellulose vapours, as the main indicator for propellants degradation degree.
Abstract: Nowadays, solid propulsion is the workhorse of a wide range of applications, from gun ammunition to missiles; and Nitrocellulose, NC, is still widely used in propellant compositions. However, its long-time storage represents a serious risk due to NC natural autocatalytic degradation process, that may lead to severe accidents. Some National Surveillance Programs continue using the so-called Stability Tests to monitor Nitrocellulose condition and storage risks; nevertheless, most users consider these tests technologically outdated and difficult to achieve a precise interpretation. This manuscript deals with this NC stability challenge, developing an innovative technology but maintaining Stability Tests phenomenological behaviour, in order to quantify naturally emitted nitrogen oxides, NOx, from Nitrocellulose vapours, as the main indicator for propellants degradation degree. However, accurate NOx quantification is usually strongly interfered by other naturally emitted vapours from gunpowder components, both in Stability Tests and in the technological proposal. Consequently, this document not only describes the technology and main development milestone, but individual components are also studied to reach a proper essay validation, employing Metal Oxide sensors, MOx. Additionally, signal deconvolution is presented to sharpen the NOx determination from interferences with two real samples (NC gunpowder), which are natural and artificially aged, determining performance of sensors and comparing conclusions with those from classical tests. Finally, presented results have shown insignificant interference of other chemicals present in the gunpowder over NOx quantification. According to these conclusions, this technology can be considered a technological improvement on NC Stability Tests.
TL;DR: In this paper , a case study is presented where an entire house was severely damaged due to spontaneous combustion of accumulated vapours of volatile substances which had become reason for subsequent explosion and devastation.
Abstract: Volatile substances comprise major constituents in dry cleaning processes. People use them extensively, ignorant towards their associated combustible properties. A case study is presented here, wherein, entire house was severely damaged due to spontaneous combustion of accumulated vapours of volatile substances which had become reason for subsequent explosion and devastation. The house was partially being used for commercial dry-cleaning purpose. The seat of fire was predominantly observed in bathroom, area near the washing machine. As per information, this portion was the main work station and an unfortunate demise of one person had occurred in the said accident. Vapours from the volatile inflammable solvents used during the cleaning process, as well as from the residues in stored dry-cleaned clothes got accumulated in the upper portion of entire house. Improper ventilation in the premise resulted in the accumulated volatiles forming a lethal source for explosion. Although ordinary people are well aware and are vigilant about fire hazards associated with highly inflammable liquids like kerosene and petrol but all may not be equally aware about fire hazards associated with highly volatile solvents. In absence of such awareness, these volatile inflammable chemicals pose far greater threat to the safety and security of the premises where they are being used. Spontaneous combustion in laundry has been reported from UK, whereas similar or severe incidences might have gone unreported in India. Chemical analysis indicated that the chemical constituents identified from the samples were volatile and inflammable in nature, possessing very high vapour pressure with very low flash point. Solvents with high vapour pressure, if used consistently, leads to consistent formation and accumulation of vapour in enclosed space. If the vapour is inflammable, it poses substantial risk of spontaneous combustion as soon as there is any source of ignition or spark, even remotely. From the detailed analysis of the samples examined, it is inferred that the chemicals detected were extremely volatile and combustible. Various components separated on the basis of the retention with the column were identified by their mass/charge (m/z) ratio in the mass spectrometer as several organic volatile compound by the instrument Head Space-Gas Chromatography-Mass Spectroscopy. When compared with petroleum fractions, some of the detected chemical compounds have high vapour pressure whereas others have low vapour pressure but all come under hazardous material category ‘3′. Similarly, several chemical compounds to have same or much lower Flash Points than petroleum fractions. It is pertinent to mention that in routine arson cases encountered by forensic scientists, petroleum fractions play an important role due to their easy availability, use and inflammability, hence chosen for comparison by. The biggest irony in such cases is that an explosive mixture is being created inadvertently by the user, slowly and silently, due to shear ignorance and lack of knowledge. The study will not only create alertness to follow safety rules while handling flammable and combustible substances, but also infuse awareness among forensic scientist and crime investigators. The investigation of explosion related incidences in a confined space poses substantial challenge for forensic scientist to locate the seat of fire and hence this case study would be of immense support to forensic community.
09 Mar 2023
TL;DR: In this article , a doubly resonant cavity that translates Kerr nonlinearity induced by an optical control field into a switch for a signal field is proposed. But the model is not suitable for logic gate operation at room temperature.
Abstract: Strong nonlinearities mediated by atomic vapours have the potential to achieve optically controlled switching at room temperature, opening the way to scalable quantum computing. A strong candidate for engineering such interactions is the combination of optical waveguides and cavities with warm alkali vapours. Here we report the implementation of a doubly resonant cavity that translates Kerr nonlinearity induced by an optical control field into a switch for a signal field. We investigate losses and consider optimised designs. We discuss this model in the context of building practical switching devices with applications to logic gate operations at room temperature.