Academic literature on the topic 'Fumes extraction'

Huelva’s copper mines (Spain) have been active for centuries but in the second half of the nineteenth century extractive activities in Riotinto, Tharsis, and other mines in the region were intensified in order to reach world leadership. The method used in these mines for copper extraction from low grade ores generated continuous emissions of fumes that were extremely controversial. The inhabitants had complained about the fumes for decades but as activity intensified so did complaints. The killing of anti-fumes demonstrators in 1888 led to the passing of a Royal Decree banning the open-air roasting of ore and to the drafting of numerous reports on the hazards of the fumes. Major state and provincial medical institutions, as well as renowned hygienists and engineers, took part in the assessment, contributing to a scientific controversy especially rich in content. In my paper I will analyse the production and circulation of knowledge and ignorance about the impact of fumes on public health, as well as the role of medical experts and expertise in the controversy. The analysis will focus on the reports drafted between the 1888 ban and its 1890 repeal, and will show the changing nature of the expert assessment and the numerous paths followed by experts in producing ignorance. The paper will conclude by considering other stakeholders, who may shed some light on the reasons behind the performance of the medical experts.

Arsenolite (As203)was historically produced as a byproduct of gold and silver extraction in southernmost Baja California Peninsula. There are in the San Antonio-El Triunfo area more than 800,000 tonnes of mine waste material with an average content of 4% arsenic oxide. The chemical reaction to produce arsenic trioxide (arsenolite) was the oxidation of arsenopyrite (AsFeS) with gold (ore) to produce iron oxides (Fe203) with gold and releasing SO2and As203 fumes. During the process the arsenic fumes sublimated onto the inner walls of old, mineral processing plants. When the chambers filled up, they were periodically emptied out on big piles of oxidized tailings. But once the plants were abandoned, the chambers remain half filled with approximately 600 tonnes of pure arsenolite. X-ray diffraction and scanning electron microscopy/energy dispersive X-ray spectrometry (EDS) indicate that the trace element content in the arsenolite and its banded structure may be due to the use of different ore for gold and silver extraction. A rough but conservative analysis of the potential leaching, based on results of the humidity cell test on mine waste material (arsenolite and arsenolite-bearing oxidized tailings) indicates that from 0.5 to 2.0 mg/l arsenic could be released into the groundwater system of the region. Real world data from the local aquifer show a close match with the calculations, indicating the close relation between arsenic content in tailings and groundwater.

Summary Scots pine (Pinus silvestris) and Norway spruce (Picea abies) were dried in a laboratory kiln, using conventional schedules with temperatures up to 60°C as well as schedules reaching 110°C. The losses of terpenes, which completely dominate the fugitive emissions from kiln drying of softwoods, were estimated by extraction of pooled subsamples from each batch, before and after drying. The original contents of terpenes were found to be in the ranges of 0.4–0.5% in pine sapwood, 0.8–1.1% in pine heartwood, and 0.02–0.08% in spruce, all calculated relative to the dry weight of the wood. The emissions from pine corresponded to 25–50% of the original content and those from spruce to 10–50%. High temperature drying in the laboratory was accompanied by larger losses, but this tendency was not found in the full-scale drying of spruce. No consistent difference was found between timber from the north of Sweden and from the south. Sampling of the vent exhaust fumes did not give results of sufficient reliability to confirm the extraction analyses.

INTRODUCTION The hazards of surgical smoke are well documented and electrosurgical units (ESUs) are an integral part of surgical practice. The aim of this study was to gauge the opinions of general surgical consultants, specialist registrars and senior theatre nurses in the Wessex Region towards the hazards of ESU smoke. MATERIALS AND METHODS A literature search was carried out using Ovid Medline. A questionnaire was sent to 169 consultants, SpRs and nurses in the 14 hospitals across the Wessex Region, exploring current practices, perceived hazards and whether adequate precautions were currently in use. RESULTS Only 3 of 98 surgeons used dedicated smoke extractors, despite the fact the majority (72%) felt that, currently, inadequate precautions were taken to protect staff and patients from surgical smoke. There was also uncertainty about the hazards amongst the respondents. CONCLUSIONS The use of smoke extraction equipment is very limited. Greater awareness of the hazards and available technology to extract fumes from the theatre environment might lead to greater uptake.

The high incidence of lung cancer observed among Chinese women has been associated with exposure to fumes from cooking oil. Polycyclic aromatic hydrocarbons (PAHs) are a class of potentially mutagenic substances emitted from cooking oils heated at high temperatures. The objective of this study was to investigate whether deep frying with different oils under different conditions leads to the development of PAHs either in the oil or in the fried product (snacks). PAH analysis was carried out with solid-phase extraction followed by reverse-phase high-performance liquid chromatography and spectrofluorometric detection. Different oils were used to fry chips and extruded snacks in different industrial plants (continuous frying) at temperatures between 170 and 205°C, and peanut oil was used to fry French fries and fish (discontinuous frying) at temperatures between 160 and 185°C. No appreciable differences in PAH load was observed in the same oil before and after frying. Both before and after frying, the benzo[a]pyrene concentration in oils ranged from trace to 0.7 ppb. All the analyzed samples, including oils from fried snacks, had benzo[a]pyrene concentrations well below the 2 ppb limit recently proposed by the European Community.

The thesis deals with the implementation of a suction system for laser welding. The specific product is grate used for outdoor drainage. The original GMAW production technology is to be replaced by a laser. During the welding of S235JR steel, a significant development of exhaust gases was observed, which subsequently made the actual process impossible. Practical experiments were performed and evaluated using tensile testing and metallographic cut. Based on the results, the optimal position of the suction nozzle and welding parameters were recommended. The obtained values were re-verified by experiment. Furthermore, a suitable extraction device was proposed and an economic evaluation was performed.

Afin de permettre la mise en place d’une filière de valorisation du CO2 issu de l’industrie sidérurgique, cette étude a pour but de proposer un nouveau procédé de dépoussiérage des fumées de hauts fourneaux qui serait placé à la suite des filières actuelles de traitement pour améliorer leur épuration. L’originalité de la technologie retenue, un lit granulaire arrosé, permet de maintenir la perte de charge constante en facilitant le réentraînement en continu des particules collectées à l’aide d’un écoulement de liquide (formant un film à la surface des collecteurs) pour ainsi pallier le problème de colmatage. Une étude hydrodynamique et des mesures d’efficacité vis-à-vis de particules de diamètre compris entre 0,5 et 10 µm ont montré que la perte de charge et l’efficacité initiale augmentaient avec la diminution du diamètre des collecteurs, ce qui est en accord avec les résultats de la littérature pour des lits granulaires secs. La présence d’un filet d’eau augmente l’efficacité initiale de collecte au détriment toutefois d’une perte de charge plus élevée. Ces observations sont liées à la diminution de la porosité du lit lorsque ce dernier est arrosé par un débit d’eau. Un bon compromis entre perte de charge et efficacité a été trouvé avec un lit composé de 50 cm de billes de 5 mm de diamètre et un débit d’eau de 12 L.min-1 pour un débit de gaz à traiter de 20 m3.h-1. Des essais de colmatage longue durée ont mis en évidence que l’efficacité du lit reste globalement constante au cours du temps, à une valeur proche de la valeur initiale. La perte de charge, bien que supérieure en début d’expérience à celle d’un lit granulaire sec, se stabilise rapidement à une valeur bien plus faible que celle mesurée pour un lit sec pour une même masse de particules collectées. Les expériences ayant été menées sur 30 h dans des conditions défavorables, nous pouvons nous attendre à ce que dans des conditions réelles de fonctionnement la perte de charge soit stable sur des temps beaucoup plus longs. Ainsi la présence de l’eau remplit bien le rôle prévu en limitant l’évolution du colmatage du lit granulaire par le réentrainement des particules collectées par le lit. Cette étude s’est achevée par le développement d’un modèle permettant de déterminer la perte de charge et l’efficacité initiale d’un lit granulaire arrosé, ce qui a abouti sur un exemple de pré-dimensionnement à échelle industrielle
In order to enable the establishment of a CO2 recovery chain sector from the steel industry, this study aims to propose a new filtration device for the dust removal of blast furnace fumes that would be placed after the current treatment chain to improve their purification. The originality of the chosen technology, a trickle bed, permits to maintain a constant pressure drop by re-entraining continuously the particles trapped on collectors thanks to a water film flow to overcome the clogging problem. A hydrodynamic study and efficiency measurements lead with particles (in a range of diameters between 0.5 and 10 μm) showed that the pressure drop and the initial efficiency increase with the decrease of the collector diameter, which is in agreement with the results of the literature for dry granular beds. The presence of water increases the initial collection efficiency at the expense of a higher pressure drop. These observations are related to the decrease of the bed porosity in presence of a water flow. A good compromise between pressure drop and efficiency was found for an air flow rate of 20 m3.h-1, a liquid flow rate of 12 L.min-1 and using a 50 cm bed composed of glass beads of 5 mm diameter. Long-term clogging tests showed that the efficiency of the bed remains globally constant over time at a value close to the initial one. The pressure drop, although higher at the beginning of the experiment than that of a dry granular bed, stabilizes rapidly at a much lower value than that measured for a dry granular bed for the same mass of particles collected. The experiments have been carried out over 30 h under disadvantageous conditions, and we can expect that under real operating conditions the pressure drop will be stable over much longer times. Thus, the presence of water plays its part by limiting the clogging evolution of the granular bed by the re-entrainment of particles collected by the bed. This study was completed by the development of a model to determine the pressure drop and initial efficiency of a trickle bed, which resulted in an example of pre-sizing of a process on an industrial scale

Les résidus d'épuration de fumées d'incinération d'ordures ménagères (REFIOM) représentent un résidu ultime destiné à l'enfouissement en centre d'enfouissement technique, après stabilisation de ses composés toxiques (les métaux lourds pour l'essentiel). Nous proposons un procédé de prétraitement de ces composés destiné à faciliter leur stabilisation par les procédés conventionnels tels que la solidification-stabilisation par liants hydrauliques et le traitement thermique à haute température, en réduisant simultanément le coût global de leur enfouissement. Cette étude a porté sur un échantillon de REFIOM contenant 12% de chlore sous forme de chlorures et 32% de calcium. Le prétraitement consiste en une solubilisation partielle en milieu aqueux alcalin destiné à extraire sélectivement et totalement les ions chlorures tout en confinant les composés toxiques en phase insoluble. Cette dernière est destinée à une stabilisation ultérieure. La forte teneur en chaux des REFIOM permet d'obtenir l'alcalinité désirée, sans apport extérieur d'aucune sorte. Nous avons montré que la déchloration diminue la fraction soluble des métaux lourds dans les matériaux stabilisés par liants hydrauliques. Nous avons étudié le cas de la solidification-stabilisation par un ciment Portland commercial. La fraction soluble des REFIOM devient, après déchloration, indépendante de leur concentration dans les matériaux stabilisés. Le traitement thermique des REFIOM déchlorés permet de réduire les quantités de gaz à épurer. Ce traitement provoque une distillation partielle de certains métaux lourds, variable selon l'espèce considérée. Elle conduit à leur concentration et permet ainsi une revalorisation ultérieure. La viabilité économique des résultats expérimentaux obtenus est discutée et montre que, pour des coûts globalement proches, la déchloration permet de réduire notablement les quantités de matériaux stabilisés à entreposer.

碩士
國立臺灣大學
職業醫學與工業衛生研究所
99
Lung cancer has been the first cause of death for a long time in Taiwan. Smoking is considered as the primary carcinogen, but the smoking rate of female is even lower in Taiwan. Epidemiology research shows that cooking oil fume is the significant risk factor of lung cancer. Restaurant workers are study subjects of this research. There were 46 waiters, 59 cooks and 20 vendors recruited to join this study. Urine samples of pre-work and post-work were collected. We use tt-DDE (trans, trans-2,4-decadienal) to represent the exposure of cooking oil fume. Cooks and Vendors used personal air sampling equipment to collect the tt-DDE while they were working. We wanted to develop an LC-MS/MS analysis method for simultaneously quantification of urinary 8-OHdG and cotinine. To monitor the oxidative stress after the exposure of cooking oil fume. The simultaneously analysis method for quantification of urinary 8-OHdG and Cotinine has been established. Quantification range of cotinine is from 0.5ng/mL to 1000 ng/mL. The limit of detection (LOD) is 0.5ng/mL. Accuracy is from -0.22% to 3.76%. Precision is from 0.86% to 7.67%. The quantification range of 8-OHdG is from 0.5ng/mL to 15ng/mL. the limit of detection (LOD) is 0.5ng/mL. Accuracy is from -2.28% to 0.19%. Precision is from 1.42% to 8.24%. R2 values are larger than 0.995. Urinary 8-OHdG concentrations of cooks and vendors are higher than waiters (p-value <0.0001) and urinary 8-OHdG concentrations of post-work are higher than of pre-work. Urinary cotinine concentrations of cooks and vendors are also higher than waiters.( p-value<0.0001)

La fumée du tabac est un aérosol extrêmement complexe constitué de milliers de composés répartis entre la phase particulaire et la phase vapeur. Il a été démontré que les effets toxicologiques de cette fumée sont associés aux composés appartenant aux deux phases. Plusieurs composés biologiquement actifs ont été identifiés dans la fumée du tabac; cependant, il n’y a pas d’études démontrant la relation entre les réponses biologiques obtenues via les tests in vitro ou in vivo et les composés présents dans la fumée entière du tabac. Le but de la présente recherche est de développer des méthodes fiables et robustes de fractionnement de la fumée à l’aide de techniques de séparation analytique et de techniques de détection combinés à des essais in vitro toxicologiques. Une étude antérieure réalisée par nos collaborateurs a démontré que, suite à l’étude des produits de combustion de douze principaux composés du tabac, l’acide chlorogénique s’est avéré être le composé le plus cytotoxique selon les test in vitro du micronoyau. Ainsi, dans cette étude, une méthode par chromatographie préparative en phase liquide a été développée dans le but de fractionner les produits de combustion de l’acide chlorogénique. Les fractions des produits de combustion de l’acide chlorogénique ont ensuite été testées et les composés responsables de la toxicité de l’acide chlorogénique ont été identifiés. Le composé de la sous-fraction responsable en majeure partie de la cytoxicité a été identifié comme étant le catéchol, lequel fut confirmé par chromatographie en phase liquide/ spectrométrie de masse à temps de vol. Des études récentes ont démontré les effets toxicologiques de la fumée entière du tabac et l’implication spécifique de la phase vapeur. C’est pourquoi notre travail a ensuite été focalisé principalement à l’analyse de la fumée entière. La machine à fumer Borgwaldt RM20S® utilisée avec les chambres d’exposition cellulaire de British American Tobacco permettent l’étude in vitro de l’exposition de cellules à différentes concentrations de fumée entière du tabac. Les essais biologiques in vitro ont un degré élevé de variabilité, ainsi, il faut prendre en compte toutes les autres sources de variabilité pour évaluer avec précision la finalité toxicologique de ces essais; toutefois, la fiabilité de la génération de la fumée de la machine n’a jamais été évaluée jusqu’à maintenant. Nous avons donc déterminé la fiabilité de la génération et de la dilution (RSD entre 0,7 et 12 %) de la fumée en quantifiant la présence de deux gaz de référence (le CH4 par détection à ionisation de flamme et le CO par absorption infrarouge) et d’un composé de la phase particulaire, le solanesol (par chromatographie en phase liquide à haute performance). Ensuite, la relation entre la dose et la dilution des composés de la phase vapeur retrouvée dans la chambre d’exposition cellulaire a été caractérisée en utilisant une nouvelle technique d’extraction dite par HSSE (Headspace Stir Bar Sorptive Extraction) couplée à la chromatographie en phase liquide/ spectrométrie de masse. La répétabilité de la méthode a donné une valeur de RSD se situant entre 10 et 13 % pour cinq des composés de référence identifiés dans la phase vapeur de la fumée de cigarette. La réponse offrant la surface maximale d’aire sous la courbe a été obtenue en utilisant les conditions expérimentales suivantes : intervalle de temps d’exposition/ désorption de 10 0.5 min, température de désorption de 200°C pour 2 min et température de concentration cryogénique (cryofocussing) de -75°C. La précision de la dilution de la fumée est linéaire et est fonction de l’abondance des analytes ainsi que de la concentration (RSD de 6,2 à 17,2 %) avec des quantités de 6 à 450 ng pour les composés de référence. Ces résultats démontrent que la machine à fumer Borgwaldt RM20S® est un outil fiable pour générer et acheminer de façon répétitive et linéaire la fumée de cigarette aux cultures cellulaires in vitro. Notre approche consiste en l’élaboration d’une méthodologie permettant de travailler avec un composé unique du tabac, pouvant être appliqué à des échantillons plus complexes par la suite ; ex : la phase vapeur de la fumée de cigarette. La méthodologie ainsi développée peut potentiellement servir de méthode de standardisation pour l’évaluation d’instruments ou de l’identification de produits dans l’industrie de tabac.
Tobacco smoke is an extremely complex aerosol composed of thousands of constituents distributed amongst the particulate and vapor phases. Toxicological effects have been linked to compounds present in both of these phases. Many biologically active compounds have been identified within tobacco smoke; however, there is a lack of studies correlating specific in vitro or in vivo biological responses to components within whole tobacco smoke. The goal of this research was to develop reliable and robust smoke fractionation methods using analytical separation and detection techniques in combination with in vitro toxicological assays. In a previous study by our collaborators, toxicological assessment of the particulate phase combustion products of twelve individual tobacco components revealed that the combustion products of chlorogenic acid were the most cytotoxic using the in vitro micronucleus test. Therefore, a preparative liquid chromatography method was developed in this work to fractionate the combustion products of chlorogenic acid to assess the bioactivity of these fractions and to identify the compounds responsible for the toxicity observed. The sub-fraction responsible for the most cytotoxic response comprised catechol, which was identified by liquid chromatography/time-of-flight mass spectrometry. Emerging studies have highlighted the toxicological significance of whole tobacco smoke and specifically the vapor phase, which shifted our focus to whole smoke analyses. The Borgwaldt RM20S® smoking machine in combination with British American Tobacco’s in vitro cell exposure chamber allow for the generation of fresh cigarette smoke in various doses and delivery to cell cultures. In vitro biological assays have a high degree of variability, thus, all other sources of variability must be accounted for to accurately assess toxicological endpoints; however, the reliability of dose delivery of the instrument had not been assessed until now. We have determined the reliability (RSD from 0.7-12%) of smoke generation and dilution by quantifying two reference standard gases (CH4 by flame ionization detection and CO by infrared absorption) and the tobacco particulate phase marker, solanesol (by high performance liquid chromatography-ultraviolet absorption detection). The relationship between dose and diluted vapor phase components found within the exposure chamber was then characterized by developing a headspace stir-bar sorptive extraction-gas chromatography/mass spectrometry method. The method repeatability gave an RSD from 10-13% for five reference compounds identified in the vapor phase of cigarette smoke. The maximal peak area response was obtained using the following experimental conditions: exposure-to-desorption time interval of 10  0.5 min, desorption temperature of 200 °C for 2 min, and a cryofocussing temperature of -75 °C. The dilution precision was found to yield a linear response of analyte abundance and was observed to be a function of concentration (RSD from 6.2-17.2 %) with quantities of 6-450 ng for the reference compounds. The findings obtained suggest the Borgwaldt RM20S® is a reliable tool to generate and deliver repeatable and linear doses of cigarette smoke to in vitro cell cultures. Our approach began with designing the methodology to work with an individual tobacco component, which could then be applied to a more complex sample, e.g., the vapor phase of cigarette smoke. The methodology developed can potentially serve as standardized methods for the assessment of instrumentation or screening of products for the Tobacco Industry.

Concerning the problem that the current facial expression analysis based on convolutional neural network (CNN) only uses the features of the last convolutional layer but the recognition rate is not high, this paper proposes the use of sub-deep convolutional layer features and builds a CNN model which fuses the features of multi-layer convolutional layers. The model uses a CNN for feature extraction and saves the deepest feature vectors and sub-deep feature vectors of the expression images. The sub-deep feature vector is used as the input of the multilayer CNN established in this paper. The processed fourth convolution layer feature is fused with the deepest feature previously saved to perform facial expression analysis. Experiments are performed on FERPLUS dataset, Cohn-Kanade dataset (CK+) and JAFFE dataset. The experimental results show that the improved network structure proposed in this paper can capture richer feature information during facial expression analysis, which greatly improves the accuracy of expression recognition and the stability of the network. Compared with the original CNN-based facial expression analysis using only the last layer of convolution layer features, using multi-layer fusion features on three kinds of datasets can improve the expression recognition rate by 33.3%, 2.3% and 22%, respectively.

Abstract Several hundred units were subjected to autoclave stress as part of the qualification of a new fast static RAM. Many units failed after autoclave stress, and these parts recovered after conventional depotting using nitric acid and a hot plate. Based on the recovery of the units, the failures were determined to be fuse-related because the nitric acid cleared the fuse cavities during depotting. Chemical analysis after thermally extracting the die from the package revealed an antimony-rich material in failing fuse cavities. Source of the antimony was linked to antimony trioxide added to the plastic package as a fire retardant. However, it was unclear whether the antimony-rich material caused the failure or if it was an artifact of thermal depotting. A new approach that did not thermally or chemically alter the fuse cavities was employed to identify the failing fuses. This approach used a combination of back-side grinding, dimpling, and back-side microprobing. The antimony-rich material found in the fuse cavity was confirmed using SEM and TEM-based EDS analysis, and it is believed to be a major contributing factor to fuse failures. However, it is unclear whether the short was caused by the antimony-rich material or by a reaction between that material and residual aluminum (oxide) left in the fuse cavity after the laser blows.

Sequential recommendation aims to predict users’ future behaviors given their historical interactions. However, due to the randomness and diversity of a user’s behaviors, not all historical items are informative to tell his/her next choice. It is obvious that identifying relevant items and extracting meaningful sequential patterns are necessary for a better recommendation. Unfortunately, few works have focused on this sequence denoising process. In this paper, we propose a PatteRn-enhanced ContrAstive Policy Learning Network (RAP for short) for sequential recommendation, RAP formalizes the denoising problem in the form of Markov Decision Process (MDP), and sample actions for each item to determine whether it is relevant with the target item. To tackle the lack of relevance supervision, RAP fuses a series of mined sequential patterns into the policy learning process, which work as a prior knowledge to guide the denoising process. After that, RAP splits the initial item sequence into two disjoint subsequences: a positive subsequence and a negative subsequence. At this, a novel contrastive learning mechanism is introduced to guide the sequence denoising and achieve preference estimation from the positive subsequence simultaneously. Extensive experiments on four public real-world datasets demonstrate the effectiveness of our approach for sequential recommendation.