Spray Type Research Articles

STUDY OF FLARE-ASSOCIATED X-RAY PLASMA EJECTIONS : II. MORPHOLOGICAL CLASSIFICATION

X-ray plasma ejections often occurred around the impulsive phases of solar flares and have been well observed by the SXT aboard Yohkoh. Though the X-ray plasma ejections show various morphological shapes, there has been no attempt at classifying the morphological groups for a large sample of the X-ray plasma ejections. In this study, we have classified 137 X-ray plasma ejections according to their shape for the first time. Our classification criteria are as follows: (1) a loop type shows ejecting plasma with the shape of loops, (2) a spray type has a continuous stream of plasma without showing any typical shape, (3) a jet type shows collimated motions of plasma, (4) a confined ejection shows limited motions of plasma near a flaring site. As a result, we classified the flare-associated X-ray plasma ejections into five groups as follows: loop-type (60 events), spray-type (40 events), jet-type (11 events), confined ejection (18 events), and others (8 events). As an illustration, we presented time sequence images of several typical events to discuss their morphological characteristics, speed, CME association, and magnetic field configuration. We found that the jet-type events tend to have higher speeds and better association with CMEs than those of the loop-type events. It is also found that the CME association (11/11) of the jet-type events is much higher than that (5/18) of the confined ejections. These facts imply that the physical characteristics of the X-ray plasma ejections are closely associated with magnetic field configurations near the reconnection regions.

Evaluation of white metal adhesion (conventional casting and thermal wire arc spraying) by ultrasonic non-destructive method

Slide bearings can be classified (as follows): bearing shells, radial and axial segments, used for turbogenerators and hydrogenerators. Slide bearings work in heavy operating conditions including their size of load, middle peripheral velocity, number of revolutions and operating temperature. Causes of the slide bearing damage is possible to divide into these types: casting defects, adhesion defects, steel substrate break, assembling defects, operating defects on the white metal surface (scribbling), insufficiency of lubricating oil, dynamic overload of the bearing, cavitation and corrosion [V. Ševčík, M. Knotek, Segmentová ložiska, SNTL Praha, 1985]. The article presents that adhesion defects can be depended on used technology for the deposition of the white metal on the steel substrate. Two types of deposition technology, conventional casting and thermal spraying, are compared by help of ultrasonic and penetrant method, metallography and X-ray diffraction.

Extinguishment of Cooking Oil Fires by Water Mist Fire Suppression Systems

A series of full-scale experiments were conducted in a mock-up commercial cooking area to study extinguishing mechanisms and effectiveness of water mist against cooking oil fires. The impact of water mist characteristics, such as spray angle, droplet size, flow rate, discharge pressure and type of nozzle, on the effectiveness of water mist against cooking oil fires was investigated. A series of oil splash experiments were also conducted to determine if the oil was splashed by water mist. In addition, the change in oil composition during heating and fire suppression was determined using Fourier Transform Infrared (FTIR) technique. The study showed that cooking oil fires were very difficult to extinguish, because they burned at high temperature and re-ignited easily due to changes in oil composition during heating and fire suppression. The water mist systems developed in the present work effectively extinguished cooking oil fires and prevented them from re-ignition. The spray angle, discharge pressure, and water flow rate were important factors to determine the effectiveness of water mist in extinguishing cooking oil fires.

Mechanical and precorroded fatigue properties of coated aluminium aircraft skin system as function of various thermal spray processes

Aluminium coatings deposited on AA2024-T3 by the flame arc, atmospheric plasma and high velocity oxyfuel (HVOF) processes were evaluated using quantitative metallography, microhardness, adhesion, three point bend and conventional fatigue tests as well as fatigue tests on precorroded samples. Comparison of the microstructures, mechanical properties, and the fatigue and precorroded fatigue properties of samples with the three types of thermal spray coating, as well as samples of bare AA2024-T3 and Alclad AA2024-T3, revealed that HVOF is the most promising thermal spray process for the deposition of aluminium coatings, and, in particular, HVOF coatings greatly increase the fatigue and precorroded fatigue lifetimes of the AA2024-T3 substrate.

Engine Room Fires & Local Fire Extinguishing Systems

10% of fatalities at sea are caused by fires.Rated by the cost of insurance claims, fires are in third place, only exceeded by grounding/collision (severe consequences) and machinery damage (high frequency) .Statistics gathered from 1992 to 1997 show that 63% of all reported fires are engine room fires. The same trend is seen for the period 1998 to 2001. These fires are often very serious fires and may disable the vessel for longer periods. A rough estimate of the related cost of an engine room fire is about £ 100.000 per minute of fire.Of all reported engine room fires, more than 50% are caused by oil leakages onto hot surfaces. SOLAS 2001 consolidated edition requires that surfaces with temperature exceeding 220 degrees C shall be insulated or shielded.To reduce or extinguish fires at an early stage without endangering people and to reduce the consequences of an erroneous release, there is a requirement in SOLAS 2000 amendments Ch.II-2, Reg.10.5.6 for a local application fire extinguishing system. The system shall be of the water spray or low expansion foam type and be capable of both automatic and manual release from both inside and outside of the machinery space. Automatic release is initiated by a separate fire detection system covering the high fire risk objects in the machinery space as separate sections. Activation of the system shall not cause shut down of main or auxiliary engines or malfunction of essential electrical systems. It may also be noted that there is no requirement for redundant water pumps, nor for a redundant power supply.To further improve the fire safety in machinery spaces, DNV has developed a class notation called F-M that has requirements in addition to SOLAS. The focus is on:-prevention of fires through requirements to the oil systems and separation and requirements for thermo scanning of hot surfaces.-quick response to fires through enhanced fire detection and confirmation of fires by use of CCTV system.-reliability of fire fighting systems through robust local extinguishing, reliable main fire fighting system and well specified fireman's equipment.

A new approach to estimating the volatilization rates of shower water-contained volatile organic compounds during showering

A mathematical hybrid-showering model was developed in order to describe the dynamic behaviour of volatile organic compounds (VOCs) contained in shower water during personal showering. The approach involves assuming a two-film theory and taking into account the dual flow patterns of “jet” and “spray” from a showerhead in order to estimate the emission of VOCs from tap water to air. The liquid-phase mass-transfer coefficients corresponding to both flow patterns and the gas-phase mass-transfer coefficient for spray droplets are estimated using the penetration theory, while the gas-phase mass-transfer coefficient for a jet-flow stream is calculated using an analogous empirical correlation. Literature-derived data were used to test the validity of the hybrid-showering model and a good correlation between literature-derived and calculated data was obtained. This study confirms the usefulness of the hybrid-showering modelling approach as regards the risk assessment of personal showering. Moreover, our simulated findings indicated that the jet-flow type showerhead should be more beneficial than the spray type showerhead as regards being associated with a lower VOC exposure risk.

수용성 뿜칠형 고무 아스팔트 방수재의 시공성 평가에 관한 연구 - 재료 조건을 중심으로 -

This study deals with the estimation of material properties according to the construction condition for water-soluble rubberized asphalt waterproofing material of spray type. In this study, the waterproofing material property by the spray construction method is suggested by means of estimation its tensile performance and temperature dependency according to mix proportion ratio(4:1, 8:1), referenced viscosity and solid content (A:360cps, 76%, B:580cps, 79%, C:490cps, 70%), spray angle(<TEX>$30^{\circ}$</TEX>, <TEX>$45^{\circ}$</TEX>, <TEX>$60^{\circ}$</TEX>), and spray distance(30cm, 50cm, 70cm). The result of testing are as follows. (1) The mix proportion ratio of principal agent and hardener is 4:1. (2) The viscosity referenced and solid content are 490cps and 70%. (3) The spray angle referenced is <TEX>$45.^{\circ}$</TEX> (4) The distance referenced from concrete surface to spray gun is 40~50cm.

여름철 자연증발시스템(NES)의 腞슬러리 증발효율 평가

본 연구는 실험방법이 간단하고 분석비요이 저렴하여, 단시간내에 세균수를 측정할 수 있는 현장적용 가능한 방법을 확립하기 위하여 냉장우육의 총균수를 표준평판배양법과 배양온도를 25<TEX>$^{\circ}C$</TEX>, 30<TEX>$^{\circ}C$</TEX>, 35<TEX>$^{\circ}C$</TEX> 별로 레자주린 환원색과 환원시간을 측정하여 상관관계를 산출하였다. 연구결과를 보면, 총균수(25<TEX>$^{\circ}C$</TEX>/72시간, Y)와 레자주린 환원시간(X)과의 상관계수는 RRT(Resazurin reducion test) 배양온도가 25<TEX>$^{\circ}C$</TEX>와 30<TEX>$^{\circ}C$</TEX>, 환원색은 청색에서 분홍색으로 변할 때가 각각 -0.95와 -0.94로서 가장 높았다. 상관계수와 환원시간을 감안할 때 RRT 배양온도는 30<TEX>$^{\circ}C$</TEX>가 적합하였으며, 이때 회귀방정식은 Y=-0.4386X + 7.7870이었으며, 돼지고기의 총균수가 <TEX>$10^2$</TEX>, <TEX>$10^3$</TEX>, <TEX>$10^4$</TEX> cfu/<TEX>$cm^2$</TEX>일 경우 검사시간은 13.2시간, 10.9시간, 8.6시간이었다. 총균수(30<TEX>$^{\circ}C$</TEX>/72시간, Y)와 레자주린 환원시간(X)과의 상관계수는 RRT 배양온도가 30<TEX>$^{\circ}C$</TEX>, 환원색은 청색에서 분홍색으로 변할 때가 -0.93으로서 가장 높았다. 이때 회귀방정식은 Y=0-0.417X + 7.5540이었으며, 돼지고기의 총균수가 <TEX>$10^2$</TEX>, <TEX>$10^3$</TEX>, <TEX>$10^4$</TEX> cfu/<TEX>$cm^2$</TEX>일 경우 검사시간은 13.3시간, 10.9시간, 8.5시간이었다. 총균수(35<TEX>$^{\circ}C$</TEX>/48시간, Y)와 레자주린 환원시간(X)과의 상관계수는 RRT 배양온도가 30<TEX>$^{\circ}C$</TEX>, 환원색은 청색에서 분홍색으로 변할 때가 -0.93으로서 가장 높았다. 이때 회귀방정식은 Y=-0.3514X + 6.7513이었으며, 돼지고기의 총균수가 <TEX>$10^2$</TEX>, <TEX>$10^3$</TEX>, <TEX>$10^4$</TEX> cfu/<TEX>$cm^2$</TEX>일 경우 검사시간은 13.5시간, 10.7시간, 7.8시간이었다. The purpose of this study was to establish the optimal operation condition of the natural evaporation system(NES) which was used for reducing swine slurry. Especially the main point of this study is to estimate the effect of climate condition(clear & rainy) and spray type(batch & flow) for the evaporation rate of swine slurry applying the NES in summer. Experiment was performed from June to August, which was generally regarded as summer in Korea, with the spray type of batch in 2000 and that of flow in 2001. As a result of experiment for batch and flow type, the averaged evaporation rate was measured into 2.71 and 3.59 l/ton . <TEX>$m^2$</TEX> . day on clear days and 0.62 and 0.66 l/ton . <TEX>$m^2$</TEX> . day on raint days, respectively. Based on the calculated evaporation rate by the climate condition and the spray type, it was proved that the averaged reduction rate for total input(1t/day) were 15.99% and 3.19% on clear and rainy days and the evaporation rate of the flow type was superior to that of the batch type by 5%, approximately. Therefore, it was concluded that the supplementary equipment, such as fan, should by operated in rainy days and the spray type of flow rather than that of batch should be recommended to increase the evaporation rate in the natural evaporation system(NES).

Numerical Simulation and Experiment on Air Washer with One Row Water Spray

The main purpose of the present work is to acquire further insight into the procedure of heat and mass transfer between sprayed water droplets and air stream in a direct evaporative air cooler used in air-conditioning systems in textile mills. The thermodynamic models of the two-phase flow in such an air treatment system have been developed for both the one row parallel flow spray and one row counter flow spray. The fields of temperature and relative humidity in the spray chamber have been obtained by calcula-tion. A series of experiments aimed at quantifying the system performance and its influence factors have been conducted. This indicates that the increases of air velocity and water/air ratio, together with the decrease of nozzle density are favorable. Comparison of these two different spray types have been carried out by means of humidity efficiency. Finally, numerical calculations have been compared with experimental results. Satisfactory agreements have been found regarding outlet air temperature while a maximum error of 10% has been observed regarding relative air humidity.

A Study of Adequate Spray Formation for Premixed Lean Diesel Combustion. An Analysis of Impingement Spray.

Premixed lean diesel combustion (PREDIC) achieves very low NOx emissions as a result of early fuel injection. Another consequence of such early injection is an increase in the amount of fuel spray reaching the cylinder wall. This results in higher fuel consumption and THC emissions. Another shortfall is that compression ignition timing control is difficult because of its dependence upon the incylinder temperature. These problems can be addressed by utilizing an impingement spray, with two nozzles. In this study, this type of spray was analyzed on spray position control, larger spray volume, and less wall wetting, among others. Also, the impingement spray structure was analyzed by cross-sectional observation using laser induced fluorescence. Spray penetration, high-density area, and plume area were measured. The impinging sprays enhance each other's spreading and mixture formation. Higher injection pressure has little effect on spray penetration and high-density area.

Comparison of adventitious shoot formation from node and leaf explants of various carnation (Dianthus caryophyllus L.) cultivars

SummaryShoot regeneration of leaf explants from in vitro plants of 35 carnation cultivars, and node explants from greenhouse plants of 38 cultivars was compared. First to third node explants cultured on medium containing 1.0 mg l–1 TDZ for 10.d and subcultured onto medium contain 1.0 mg l–1 BA showed a high shoot regeneration percentage, while the upper node showed higher shoot regeneration ability than the lower node. In contrast, there was no difference in regeneration ability among the first to sixth in vitro leaves (cultured on medium with 0.5 mg l–1 IBA and 0.22 mg l–1 TDZ). In both node and leaf explants regeneration ability was different depending on the cultivar, and there was no difference between standard and spray types. The correlation coefficients between regeneration percentage and the number of shoots per regenerating node and leaf explants were significantly positive (r=0.536** and 0.720**, respectively P<0.01). The correlation coefficient between shoot regeneration percentage of node and leaf explants was significantly positive (r=0.213*; P<0.05). Histological observations on adventitious shoot organogenesis by SEM and light microscopy showed that in both node and leaf explants, shoot primordia were regenerated from the transition zone between the leaf base and the stem. In both node and leaf explants shoot primordia regenerated in the cortex tissue near the wound surface.

D126 噴霧燃焼器におけるエア供給方法の改善によるエミッション低減

To reduce its size and improve exhaust emission property, it is effective for spray type combustor to increase burning velocity by promoting such as fuel evaporation, diffusion, mixture of fuel and air. Excessive swirl inhibit the mixture in centrifugal direction of fuel and air to deteriorate combustion condition. This paper reports the coexistence of high load combustion and emission reduction experimentally confirmed having shorter flame length, compared to swirl type combustor, by making many air injection holes along combustion cylinder axis which causes creating small turbulence.

Experimental study on the interaction of fine water spray with liquid pool fires

An experimental study of the interaction of a fine water spray with liquid pool fires was performed. Spatially resolved droplet size, velocity distributions, and volume flux of the fine water spray have been obtained in two types of pressure-atomized fine spray, using LDA/APV technology. A method to correct for the presence of droplets is presented and used to determine the heat release rate using a cone calorimeter system, the effects of water spray application on the heat release rate for liquid pool fires were studied. It was found that the volume flux of the water spray is an important factor to determine the liquid pool fire behavior. For the current experimental conditions, the flame was enlarged when lower volume flux of water is used, and suppressed significantly when larger volumes of water are used. Two opposing mechanisms compete when water sprays are applied, which is more complex than the halon agents, such as 1301. The combustion enhancement becomes insignificant when water sprays with the proper characteristics such as adequate volume flux are applied to the diffusion flame in a confined space.

Physiological Responses of Chrysanthemum Petals during Senescence

Flower senescence was studied in three cultivars of Chrysanthemum coronarium L.: Snowball White, Yellow Chandrama (standard type flowers) and Spray Button (spray type flowers). Spray button flowers exhibited least respiration rate, less efflux of ions, minimum protease activity and less decline in fresh mass, relative water content and total soluble protein content with the progression of senescence. The Snowball White flowers showed highest respiration rate, great efflux of ions, maximum protease activity, high activity of hydrolytic as well as proteolytic enzymes, and high decline in fresh mass, relative water content, and total soluble protein content. Yellow Chandrama flowers showed responses similar to Snowball White flowers.

A model for fuel spray penetration

A new model for fuel spray penetration (location of spray tip) is suggested and validated against available experimental data. Simple analytical expressions for fuel spray penetration are derived in two limiting cases: the initial stage and the two-phase flow regime. At the initial stage, the effects of droplet drag and entrainment of air are accounted for. In the case of the two-phase flow, it is assumed that the spray droplets have the same velocities as the entrained air. The characteristic time of droplet break-up in the spray is estimated for both bag and stripping break-up mechanisms. For realistic diesel spray parameters, the droplet break-up takes place almost immediately after the droplets leave the nozzle. This leads to a considerable shortening of the initial stage and a rapid conversion of the flow to the two-phase stage. This allows the analysis to be restricted to the two-phase flow approximation for this type of spray. The expressions for spray penetration derived in this paper give more accurate predictions compared with those suggested earlier.

Experimental study on premix combustion at isosceles triangle type rate of heat release for squish type combustion chamber

This paper presents a theory on premix fuel combustion at near isoceles triangle type rate of heat release, describes the measures taken for the combustion system, points out its many theoretical advantages, and that it can solve effectively the problems of rough running, fuel consumption and exhaust emission. Two squish lip type combustion chambers are designed to match separately with multiple holes injector and conical spray type injector in order to achieve premix combustion at near isosceles triangle type rate of heat release. Experimental studies on two single cylinder diesel engines showed that premix combustion at isosceles triangle type rate of heat release resulted in longer ignition delay period, larger amount of fuel injected into cylinder during the ignition delay period, lower maximum pressure, better fuel economy, and better exhaust emission.

The effect of water spray upon incineration flue gas clean-up

The existence of liquid water was found very important in incineration flue gas clean-up systems for enhancing the absorption of acid components contained. In a newly developed incineration flue gas clean-up tower, which works in a semi-dry mode, the water is injected in the form of spray to maximum its contact surface with the gas. The criteria for the design of the water nozzles would be high water concentration but no liquid impinging on the solid wall and complete evaporation inside the tower. In order to optimize the atomizer design, the effects of the spray type (hollow or solid cone), their initial droplet size distribution and water flow rate on the performance of the acid gas absorption were investigated. The liquid behaviour was studied with a fluid dynamic simulation code, and the overall performance was checked experimentally. This paper presents the use of a commercial CFD code, FLUENT, and some modifications made during such investigation. The modification includes the viscosity of the flue gas defined as a function of the temperature, and the initial mass fraction of different droplet size group described with an exponential distribution formula of Rosin-Rammler. The investigation results (the optimal spray parameters) were used to guide the water nozzle design. The general performance of the flue gas clean-up system measured during the plant operation complied with the design criteria.

小売店におけるスプレーカーネーション切り花の品質評価と品質保持期間，体内水分率および器官別糖含有量の関係

Cut flowers of the spray type carnation 'Light Pink Barbara' graded as : high(H), middle(M) and the low(L) in a flower market were investigated with respect to their vase life, fresh weight, and water and sugar contents in the floral organs. 1. Total fresh weight, percent water content and water absorption were highest in H and lowest in L throughout the experiment. 2. Buds of H and M opened normally within 10 days, whereas those of L blasted ; vase life in H and L were 15 and 10 days, respectively. 3. Petals of H and M conteined 11 to 13 mg/100mg dry weight (DW) of glucose and fructose, respectively, at the beginning of the experiment ; the concentration in H decreased to about 8 mg/100g DW within four days and sustained this level, whereas in M, they decreased to about 4 and 6 mg/100g DW by the end of the experiment. Petals of L contained 4 and 6 mg/100g of glucose and fructose, respectively, throughout the experiment. 4. Sucrose contents of leaves were 10 mg/100mg in H, 12 mg/100mg in M and about 2 mg/100mg in L ; fructose and glucose contents were about 1 mg/100mg in the grades. These levels persisted throughout the experiment in leaves of all grades. 5. Sucrose contents in stem of the three grades ranged between 4 to 6 mg/100mg DW throughout the experiment ; glucose content decreased from 2 mg to 0.5 mg/100mg during the same period. 6. When cut flowers were treated with silver thiosulphate, a substantial amount of silver was detected in petals, indicating that a significant uptake of the solution occurred. These results indicate the high water content percent of the cut flower with high fructose and glucose contents in the petals contribute to long vase life in spray carnation treated with silver.

Agricultural Intensification and Pest Outbreaks: A Reappraisal of Events in the Sudan Gezira

Pest control crises in agricultural systems often have been attributed to either direct or indirect effects of pesticide use and less frequently to the underlying cropping structure and environment. As an example of intensive, high-input agriculture, the Gezira Irrigation Scheme in Sudan and the pest crises that occurred there in the late 1970s are drawn upon to examine 2 principal arguments that have frequently been invoked to explain causes of pest outbreaks in crops. Both arguments considered pesticides to have been the principle inducers of the pest crises in the Sudan Gezira, but differed in their evaluation of the responsible mechanisms. One argument considered that pesticides indirectly led to the depletion of natural enemies and the concomitant rise in pest status of Bemisia tabaci (Gennadius), whereas the other argued that pesticides directly affected B. tabaci populations through fertility stimulation and resistance to insecticides. A 3rd argument is submitted herein to suggest that rising pest problems occurred in conjunction with a program of agricultural intensification and diversification that took place in the Gezira from the late 1950s through the late 1970s. This process began with crop intensification, was followed by favorable changes in agronomic practices from the standpoint of a crop pest, and together led to increasing densities of pests responding to significant improvements in the environment. Finally, management reacted to the pest surge by increasing the number of spray applications and types of insecticides used. Dramatic changes in the crop environment are viewed as having given rise to pest populations that were intrinsically capable of exploiting an expanded, improved resource base and that ultimately exceeded the inherent limitations of pesticides to effectively manage their populations.

スプレーギク切り花のａｃｔｉｖｅ ＭＡ包装貯蔵

MA包装によるスプレーギク切り花の貯蔵ならびに貯蔵後の日持ち試験を行った.スプレーギクの呼吸速度は, 2%O2雰囲気で空気下での呼吸量の1/2に抑制された.O2の低減を呼吸に依存するpassive MA包装では, 厚いポリエチレンフィルム(PE)を用いても袋内O2濃度を10%以下に低下させることはできなかった.低O2雰囲気を実現するには, ガス分離膜方式のN2発生装置を用いてPE袋内を2%O2のN2富化空気で置換して密封するactive MA包装が有効であった.厚さ0.1mmのPEまたは厚さ0.02mmのポリプロピレンフィルム(PP)を使用したactive MA包装により, 10℃で10日間スプレーギクの開花を完全に抑制することが可能で, 貯蔵後, 空気下20℃での鑑賞可能日数は13&acd;15日であった.一方, 湿式貯蔵, 有孔包装貯蔵の鑑賞可能日数は, それぞれ6日と3日で, passive MA包装ではPP, PEともに7日であった.葉の緑色度とアスコルビン酸含量は, 貯蔵スプレーギクの品質評価指標として有用であり, これらの評価法によっても, active MA包装は, passive MA包装や空気下湿式貯蔵, 空気下乾式貯蔵よりも顕著な貯蔵性を有することが分かった.