Cyclone Collector Research Articles

Aerosols Contamination in the Dental Practice Following Everyday Procedures: An Observational Study.

The purpose of the present observational study was to evaluate the bacterial load in the air following various dental procedures. Air contamination following seven aerosol-generating dental procedures was assessed. The air volume was sampled by a wet cyclone collector for 10 min during 10 sessions of the following procedures: air-polishing, ultrasonic instrumentation, manual instrumentation, rubber cup polishing, cavity preparation with a 1:5 red contra-angle, cavity preparation with turbine and Low Volume Evacuator (LVE), and cavity preparation with turbine and High Volume Evacuator (HVE). Contamination of the sampled solution was determined using ATP (Adenosine TriPhosphate) quantification of the viable bacterial count, and compared to baseline measurements. The baseline air contamination was 1.45 (0.85-2.04) CFUs/L of air. The highest increase in air contamination was observed after the use of a turbine with LVE, with an average of 7.38 (95% CI 3.87-10.89) CFUs/L of air (p < 0.01). The use of the turbine with HVE and the use of the red hand-piece resulted in non-significant increases in bacterial counts compared to baseline (2.98 [1.34-4.63] and 2.70 [0.18-4.22] CFUs/L of air respectively). The application of air polishing, ultrasonic instrumentation, hand instrumentation and rubber cups did not result in a higher bacterial count than the baseline. Routine professional oral hygiene procedures do not increase air contamination. However, cavity excavation with LVE creates a significantly higher bacterial count in the air.

Rapid detection of explosives in collected dust using ion mobility spectrometry

Vapor and particulate matter from explosives can be adsorbed onto dust, enabling their detection in security and military applications. In this study, model explosive-adsorbed dust specimens were prepared using four types of dust from two inorganic substances [silica (SL) and clay (CL)] and two organic materials [sawdust (SD) and cotton fabric (CF)]. Three explosives, namely 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), and pentaerythritol tetranitrate (PETN), were investigated, along with two different collection filters of poly(tetrafluoroethylene) (PTFE) and lens cleansing paper (LCP). The dust was sprayed in a hood and collected using a cyclone collector. The explosive components present in the dust were rapidly detected using ion mobility spectrometry (IMS). The adsorption efficiencies of TNT, RDX, and PETN onto dust were 36 – 97, 45 – 76, and 37 – 90 %, respectively, and the values of the inorganic dusts were higher than those of the organic dusts. The dust collection rate ranged from 5 to 15 %, and decreased in the order of CL > CF > SL = SD. The factors influencing rapid explosive detection were the intrinsic vapor pressure of the explosive, interactions between the dust and the explosive, thermal conductivities of the dusts and collection filters, and structure of the collection filter. Due to the low vapor pressure of RDX, this explosive was detected later than TNT and PETN. In most cases, detection was more rapid when using the LCP than when using the PTFE because of the thicker and woven structure of the PTFE filter. The detection limits achieved using the LCP (0.049 – 1.17 μg) were lower than those of the PTFE (0.67 – 10.05 μg). When the PTFE was used, the detection limits for the organic dusts were lower than those for the inorganic dusts. Notably, the detection limits of the explosives adsorbed onto dust were significantly higher than those of the pure explosives.

ПРОМИСЛОВИЙ ЦИКЛОННО-РОТАЦІЙНИЙ ПИЛОВЛОВЛЮВАЧ

Cyclone equipment is easy to manufacture and operate, versatile and economical, but its main drawback is the inability to capture finely dispersed dust. The article discusses the most important characteristics of the highly efficient industrial cyclonic rotary dust collector developed by us. The apparatus implements the principle of two-stage separation of heterogeneous dust-gas systems in a centrifugal field. In the first stage, working on the principle of a cyclone, and in the second - working on the principle of a rotary dust collector. During operation of the apparatus, a higher pressure on the periphery of the rotating part returns a concentrated dusty flow with a low gas flow to the cyclone part. Formed by a gap, between the cyclone body and the dividing cone, a closed circuit connects the output and input of the cyclone-rotational dust collector to each other. There is a negative feedback - an effective control mechanism for such complex probabilistic systems as gas heterogeneous curvilinear flows. Negative feedback stabilizes the processes occurring in such flows. The energy of the electric motor is used in the cyclone-rotational dust collector for the movement of dusty gas, concentration, coagulation of fine dust, its return from the rotary to the cyclone zone, dispersion and capture, with the aim of saving energy and material resources. The main task of the theory of centrifugal separation of dusty flows is to find the minimum diameter of a particle that has a practically perceptible relative radial velocity. Known deterministic models of centrifugal separation are either too simple and ignore many factors that determine the process, or in attempts to account for them are too cumbersome and difficult to solve, although they are also not free from various assumptions and limitations. The stochastic model takes into account the integral set of various influences on the radial drift of the Stokes particle from the center to the periphery of the swirling flow. The paper presents the results of the study of the structure of the three-dimensional two-phase gas flow with highly dispersed inclusions in cyclonic-rotary dust collectors using 3D geometric models with the aim of visualizing these flows using computer graphics methods. Numerical studies were carried out using the k-e model of turbulence with scaled wall functions.

Numerical Simulation of Dust Removal in the Cyclone Collector of a Straw Crusher Based on a Discrete Phase Model

The cyclone dust collector is an important subsystem of straw crushers used in agriculture. In the present study, a new type of dust collector with involute morphology is proposed to obtain better dust removal efficiency with respect to that of classical tangential and spiral dust collectors. A discrete phase model (DPM) method is used in synergy with a turbulence model, and the SIMPLE algorithm to simulate the flow field inside the dust collector and the related particle dynamics. It is shown that the internal flow field features a primary swirl, a secondary swirl and blockage effects. Moreover, for the involute dust collector, the tangential velocity in the initial stage and the pressure in the high-pressure area are larger than those obtained for the classical types. The dust removal efficiency is 37.11%, 25.3%, and 16.37% for the involute type dust collector, the tangential type and the spiral type, respectively.

Теорія і практика використання циклонів на деревообробних підприємствах

Теоретично обґрунтовано доцільність зміни геометричних розмірів циклона та на цій основі розроблено нову конструкцію пиловловлювача. Наведено характеристику основним типам циклонів, що використовуються у деревообробній галузі. Проаналізовано наявні підходи до математичного моделювання аеродинамічних процесів у циклонах. Наведено нову математичну модель руху запиленого повітря всередині сепаратора, яка ґрунтується на сумісному розгляді рівнянь Нав'є-Стокса для в'язкої стисливої рідини (газу), рівняння нерозривності, рівнянь стану і рівнянь балансу тепла. Для циклону типу ЦН-15 записано початкові і граничні умови. Розв'язано отриману повну систему диференціальних рівнянь у частинних похідних та досліджено вплив геометричних розмірів сепаратора на експлуатаційні показники апарату. Числовий аналіз задачі проведено для циклона з фіксованими геометричними параметрами. Досліджено залежність гідравлічного опору циклона від таких параметрів, як висота циліндричної частини, глибина занурення вихлопної труби, висота конічної частини, діаметр вихлопної труби, діаметр пиловипускного патрубка. Досліджено розподіл статичного тиску всередині корпуса циклона. Під час досліджень розглядали різні діаметри пиловипускного отвору, а також різні значення висоти циліндричної частини. Досліджено поле швидкостей запиленого потоку всередині пиловловлювача, зокрема, її тангенціальна та осьова складові. На основі розробленої математичної моделі побудовано ізолінії швидкості потоку у характерних площинах, які проходять через вертикальну вісь циклона. Для підтвердження адекватності запропонованої математичної моделі результати числового аналізу підтверджено експериментальними дослідженнями. Для цього розроблено конструкцію експериментального стенда для проведення досліджень, у якій передбачено можливість зміни висоти циліндричної частини, глибини занурення вихлопної труби, площі поперечного перерізу вихлопної труби та використання різних типів конічної частини бункерів.

Improving Energy and Environmental Efficiency of Flue Gas Cleaning at Thermal Power Plants

The aim of the work is to improve cyclone and filter dust collectors by increasing the efficiency of fine particle deposition classes PM10, PM2,5 as well as reducing energy and material costs. The analysis of existing methods of cyclonic filtration of industrial dispersed emissions is carried out. The laboratory tests of the cyclone filter, made by modernization of the cyclone CN-11-200, were performed, the aerodynamic characteristics of its operation were found. The calculated determination of the efficiency of suspension deposition from multiphase flow in the separator using a dimensionless Rer criterion is performed, derived from the Navier-Stokes single-phase flow equations of motion and the particle motion equation based on Newton’s law. A numerically studied the aerodynamic parameters of the cyclone on the basis of computational fluid dynamics methods. For mathematical modeling of turbulence we used the DES model

Additive Manufacturing of Devices Used for Collection and Application of Cereal Rust Urediniospores.

Optimized inoculation procedures are an important consideration in achieving repeatable plant infection when working with biotrophic rust fungi. Several plant pathology laboratories specializing in rust research employ a system where the collection and application of fungal spores are accomplished using an exchangeable gelatin capsule. Urediniospores are collected from erumpent pustules on plant surfaces into a capsule fitted to a cyclone collector controlled by a vacuum pump. By adding light mineral oil to the same capsule, the spore suspension is then sprayed onto plants by means of a dedicated atomizer (inoculator) connected to an air pressure source. Although devices are not commercially available, modern day technologies provide an opportunity to efficiently design and manufacture collectors and inoculators. Using a process called Additive Manufacturing (AM), also known as “3D printing,” the bodies of a collector and inoculator were digitally designed and then laser-sintered in nylon. Depending on availability, copper or aluminum tubes were fitted to the bodies of both devices afterward to either facilitate directed collection of spores from rust pustules on plant surfaces or act as a siphon tube to deliver the spore suspension contained in the capsule. No statistical differences were found between AM and metal inoculators for spray delivery time or spore deposition per unit area. In replicated collection and inoculation tests of wheat seedlings with urediniospore bulks or single pustule collections of Puccinia triticina and P. graminis f. sp. tritici, the causal organisms of leaf rust and stem rust, consistent and satisfactory infection levels were achieved. Immersing used devices in acetone for 60 s followed by a 2 h heat treatment at 75°C produced no contaminant infection in follow-up tests.

Water saving performance and macro fluid analysis of a new cyclonic water collector

Power and chemical plants entail serious water loss during their operation. In order to save water by alleviating the loss of the circulating water in the cooling tower, a FLUENT simulation is performed to design and analyze a cyclonic water collector. The geometrical structure of the collector was such designed that the trajectory of the steam is optimized. The turbulence caused by the collector increases the possibility for collisions between water molecules, and the accumulation of tiny drops could be recycled. The results of the numerical simulation and the experiment verification demonstrate the ability of the proposed device to save much water. Furthermore, the mechanisms for water recycling and water saving are elucidated clearly through the gas-liquid coupling of the circulating water and cooling water. The present theory gives deep insights into the optimization of water-saving facilities and improvement of water-saving efficiency.

First Report of Pseudomonas syringae pv. actinidiae on Kiwifruit Pollen from Argentina

During last years, in Mar del Plata (Argentina) area, many kiwifruit orchards composed by only male plants (Actinidia deliciosa cv. Chieftain) have been established for pollen production and commercialization, since the country was considered unaffected by Psa. When mature, the anthers are detached and dried, and grains of pollen collected with a portable cyclonic pollen collector. Then, routine controls aimed to assess the risk of infection by Pseudomonas syringae pv. actinidiae (Psa), the causal agent of kiwifruit bacterial canker (Takikawa et al., 1989), are carried out by plating 1 gram aliquots of pollen on semi-selective medium (modified KB) and incubating plates for 48-72 h at 27 °C. During one of these controls, in February 2015, some bacterial colonies with morphological features similar to Psa were detected. After purification, four of them (labeled as Arg1.1 to Arg2.3) were found to be gram negative, non-fluorescent, positive for levan production, and caused hypersensitive response on tobacco. ...

サイクロン型集塵器における離散要素モデルと連続体モデルによる数値解析および粒子挙動の観察

サイクロン型集塵器における離散要素モデルと連続体モデルによる数値解析および粒子挙動の観察

Separation of the desired product from aerosol flows in the manufacture of carbon black (a review)

The current trends of the development of studies and technologies for the separation of a target product from aerosol flows in the manufacture of carbon black are surveyed. Studies oriented to decreasing material and power consumption in the processes of carbon black production are analyzed. An analysis of aerosol coagulation mechanisms and the dependence of the rate constant of coagulation on the physicochemical properties of dispersed carbon is given. The precipitation of the target product in a cyclone collector is considered. Studies directed toward an improvement in the quality and effectiveness of thermoresistant filtering materials and bag-type filters with their use are analyzed. Some results of the experimental studies of the filtration of a dispersed carbon aerosol in a layer of porous carbon granules are given.

Mathematical modeling of cleaning dust-laden gas flows in the cyclone dust collector

The issues of developing a mathematical model for calculating the aerodynamic drag and collection efficiency of solid particles in the cyclone collector, which takes into account the geometry and the opening angle of the louver element of designed dust collector, are considered in the paper.Experimental studies of the cyclone collector are given and the adequacy of the developed mathematical model is verified. Experimental data processing has allowed to determine the dimensionless coefficients n, m, l, included in the equation for determining fractional dust collection efficiency in the developed dust collector.Theoretical calculation of aerodynamic drag is conducted and the technique, suitable for the cyclone collector is determined by comparing with experimental results. The discrepancy between the experimental and theoretical data is 13.9 %. Dust collection efficiency is theoretically calculated using the mathematical model. The discrepancy between the experimental and theoretical data is 1.06 %. Experimental data processing is conducted and criterion equation for calculating partial coefficients of cleaning is found.

Leaching of elements from flue dust produced in copper scrap smelting process

To understand the features and leaching characteristics of copper (Cu) scrap smelting dust and its potential risk to environment and humans, three types of smelting dust were sampled and investigated. The dust samples were collected from the dust captured by cyclone collector, panel cooler, and bag house in a typical Cu scrap smelting process of a factory in Guangxi of China. Zinc (Zn), Cu and lead (Pb) were the main elements of the samples of cyclone collector dust (CCD), panel cooler dust (PCD), and bag house dust (BHD). There were less arsenic (As), Pb and Cu in CCD than PCD and BHD, and PCD contained more manganese (Mn), nickel (Ni), and iron (Fe) than BHD. The particle shapes of BHD appeared more regular than CCD and PCD, and energy dispersive X-ray spectroscopy analysis illustrated the compositions of selected surface areas of three samples. The size of particles ranged from 0.011 to 33.11 μm in CCD, from less than 1 μm to several mm in PCD, and from 0.832 to 363.078 μm in BHD. The main elements in leachate were Zn and Mn from CCD, Zn, cadmium (Cd) and Pb from PCD, Zn, Mn and Cd from BHD. The leaching toxicity risk of Cd, Mn, and Zn of PCD and BHD was higher than CCD.

Trace metals in fugitive dust from unsurfaced roads in the Viburnum Trend resource mining District of Missouri—Implementation of a direct-suspension sampling methodology

Fugitive dust from 18 unsurfaced roadways in Missouri were sampled using a novel cyclonic fugitive dust collector that was designed to obtain suspended bulk samples for analysis. The samples were analyzed for trace metals, Fe and Al, particle sizes, and mineralogy to characterize the similarities and differences between roadways. Thirteen roads were located in the Viburnum Trend (VT) mining district, where there has been a history of contaminant metal loading of local soils; while the remaining five roads were located southwest of the VT district in a similar rural setting, but without any mining or industrial process that might contribute to trace metal enrichment. Comparison of these two groups shows that trace metal concentration is higher for dusts collected in the VT district. Lead is the dominant trace metal found in VT district dusts representing on average 79% of the total trace metal concentration, and was found moderately to strongly enriched relative to unsurfaced roads in the non-VT area. Fugitive road dust concentrations calculated for the VT area substantially exceed the 2008 Federal ambient air standard of 0.15μgm−3 for Pb. The pattern of trace metal contamination in fugitive dust from VT district roads is similar to trace metal concentrations patterns observed for soils measured more than 40years ago indicating that Pb contamination in the region is persistent as a long-term soil contaminant.

오일미스트용 사이클론 집진기에 관한 기초 설계 -오일미스트 및 슬러지 입자 융합연구-

Dust collecting performance of cyclone collector for oil mist was alalyzed in the study. The purposes of using cutting fluid during cutting have been colling, lubricating, chip washing and anti-corroding. However, the present manufactaring industry restricts the use of cutting fluid because cutting fluid confains poisonous substances which are harmful to the human body. Also, the optimum design oil-mist collector. The new oil mist collector was designed. In the near future, this device must be tested in the real machining center and CNC machine. Cutting using oil-mist showed better cutting characteristics than dry, air and fluid cutting with respect to by cutting force, tool wear and surface roughness. The model(A, B Type cyclone) of the set of fixture and alveolus are made by using a CAE software. Finally, we have obtained a model A Type solution by using orthogonal array. Therefore, it could be confirmed that as the model-A was increased and model-B was decreased, cut diameter was decreased.

Elemental Composition of PM2.5 Particles Sampled in Industrial and Residential Areas of Taif, Saudi Arabia

This paper describes the first part of a project conducted to evaluate the trace element composition of atmospheric aerosol particles (PM2.5) and to determine their influence on air quality in Taif city, Saudi Arabia. PM2.5 particles were collected from two different sites (industrial and residential) in Taif during the summer of 2011. The industrial site was situated in the largest industrial area of Taif, and the residential site was situated in the city’s most crowded area. PM2.5 samples were collected on polycarbonate filters using a cyclonic collector. Each sample was collected over a 24 hour period and new samples were collected weekly. Average PM2.5 concentrations of 47 ± 15 and 46 ± 31 µg/m 3 were seen in the industrial and residential areas, respectively. An Energy Dispersive X-ray Fluorescence (EDXRF) spectrometer with a Mo secondary target was used to analyze the solid samples because of the relative simplicity of the technique for filter analysis. The use of a Mo secondary target is advantageous, because it decreases the impact of continuum radiation from the X-ray tube and increases the signal to background ratio. Quantitative X-ray Analysis Software (PyMca) was used to perform quantitative analysis of the atmospheric aerosols. The analysis resulted in detected concentrations for sixteen elements; Si, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Pb and Black Carbon (BC). Using Principal Component Analysis (PCA) it was possible to distinguish between natural and anthropogenic sources. The measured concentrations of the potentially hazardous trace elements Cu, Cr, Mn, Ni and Pb were below the limits defined by international guidelines and national standards for ambient air quality. However, further long-term research will be required to validate the quantification of trace elements in particulate matter in Taif.

Relationship between airborne detection of influenza A virus and the number of infected pigs

Influenza A virus infects a wide range of species including both birds and mammals (including humans). One of the key routes by which the virus can infect populations of animals is by aerosol transmission. This study explored the relationship between number of infected pigs and the probability of detecting influenza virus RNA in bioaerosols through the course of an acute infection. Bioaerosols were collected using a cyclonic collector in two groups of 7week-old pigs that were experimentally infected by exposure with a contact infected pig (seeder pig). After contact exposure, individual pig nasal swab samples were collected daily and air samples were collected three times per day for 8days. All samples were tested for influenza by real-time reverse transcriptase (RRT)-PCR targeting the influenza virus matrix gene.All pigs’ nasal swabs became influenza virus RRT-PCR positive upon exposure to the infected seeder pig. Airborne influenza was detected in 28/43 (65%) air samples. The temporal dynamics of influenza virus detection in air samples was in close agreement with the nasal shedding pattern in the infected pigs. First detection of positive bioaerosols happened at 1day post contact (DPC). Positive bioaerosols were consistently detected between 3 and 6 DPC, a time when most pigs were also shedding virus in nasal secretions. Overall, the odds of detecting a positive air sample increased 2.2 times for every additional nasal swab positive pig in the group. In summary, there was a strong relationship between the number of pigs shedding influenza virus in nasal secretions and the generation of bioaerosols during the course of an acute infection.

Multiplex Detection of Protein Toxins Using MALDI-TOF-TOF Tandem Mass Spectrometry: Application in Unambiguous Toxin Detection from Bioaerosol

Protein toxins, such as botulinum neurotoxins (BoNTs), Clostridium perfringens epsilon toxin (ETX), staphylococcal enterotoxin B (SEB), shiga toxin (STX), and plant toxin ricin, are involved in a number of diseases and are considered as potential agents for bioterrorism and warfare. From a bioterrorism and warfare perspective, these agents are likely to cause maximum damage to a civilian or military population through an inhalational route of exposure and aerosol is considered the envisaged mode of delivery. Unambiguous detection of toxin from aerosol is of paramount importance, both for bringing mitigation protocols into operation and for implementation of effective medical countermeasures, in case a "biological cloud" is seen over a population. A multiplex, unambiguous, and qualitative detection of protein toxins is reported here using tandem mass spectrometry with MALDI-TOF-TOF. The methodology involving simple sample processing steps was demonstrated to identify toxins (ETX, Clostridium perfringes phospholipase C, and SEB) from blind spiked samples. The novel directed search approach using a list of unique peptides was used to identify toxins from a complex protein mixture. The bioinformatic analysis of seven protein toxins for elucidation of unique peptides with conservation status across all known sequences provides a high confidence for detecting toxins originating from any geographical location and source organism. Use of tandem MS data with peptide sequence information increases the specificity of the method. A prototype for generation of aerosol using a nebulizer and collection using a cyclone collector was used to provide a proof of concept for unambiguous detection of toxin from aerosol using precursor directed tandem mass spectrometry combined with protein database searching. ETX prototoxin could be detected from aerosol at 0.2 ppb concentration in aerosol.

Detection of Airborne Influenza A Virus in Experimentally Infected Pigs With Maternally Derived Antibodies

This study assessed whether recently weaned piglets with maternally derived antibodies were able to generate infectious influenza aerosols. Three groups of piglets were assembled based on the vaccination status of the dam. Sows were either non-vaccinated (CTRL) or vaccinated with the same (VAC-HOM) strain or a different (VAC-HET) strain to the one used for challenge. Piglets acquired the maternally derived antibodies by directly suckling colostrum from their respective dams. At weaning, pigs were challenged with influenza virus by direct contact with an infected pig (seeder pig) and clinical signs evaluated. Air samples, collected using a liquid cyclonic air collector, and individual nasal swabs were collected daily for 10 days from each group and tested by matrix real-time reverse transcriptase polymerase chain reaction (RRT-PCR) assay. Virus isolation and titration were attempted for air samples on Madin-Darby canine kidney cells. All individual pigs from both VAC-HET and CTRL groups tested positive during the study but only one pig in the VAC-HOM group was positive by nasal swab RRT-PCR. Influenza virus could not be detected or isolated from air samples from the VAC-HOM group. Influenza A virus was isolated from 3.2% and 6.4% air samples from both the VAC-HET and CTRL groups, respectively. Positive RRT-PCR air samples were only detected in VAC-HET and CTRL groups on day 7 post-exposure. Overall, this study provides evidence that recently weaned pigs with maternally derived immunity without obvious clinical signs of influenza infection can generate influenza infectious aerosols which is relevant to the transmission and the ecology of influenza virus in pigs.

Modeling of the hydrodynamics of a cyclonic rotational dust collector of increased efficiency

The results of investigation of the structure of a three-dimensional two-phase gas flow with highly dispersed inclusions in a cyclonic-rotational dust collector with the use of a 3D geometrical model and methods of computer graphics for flow visualization are presented. Numerical investigations were carried out on the basis of the k–e model of turbulence with scaled wall functions. Good agreement between the calculated and experimental results has been obtained.