Cyclone Type Research Articles

Energy and exergy aanalyses of drying of eggplant slices in a cyclone type dryer

In this paper, the energy and exergy analyses of the drying process of thin layer of eggplant slices are investigated. Drying experiments were conducted at inlet temperatures of drying air of 55, 65 and 75°C and at drying air velocities of 1 and 1.5 ms-1 in a cyclone type dryer. Using the first law of thermodynamics, energy analysis was carried to estimate the ratios of energy utilization. However, exergy analysis was accomplished to determine type and magnitude of exergy losses during the drying process by applying the second law of thermodynamics. It was deduced that eggplant slices are sufficiently dried in the ranges between 55-75°C of drying air temperature and at 1 and 1.5 ms-1 of drying air velocity during 12000-21600 s despite the exergy losses of 0-0.739 Us-1.

Evaluation of convective heat transfer coefficient of various crops in cyclone type dryer

Abstract In this paper, an attempt was made to evaluate the convective heat transfer coefficient during drying of various crops and to investigate the influences of drying air velocity and temperature on the convective heat transfer coefficient. Drying was conducted in a convective cyclone type dryer at drying air temperatures of 60, 70 and 80 °C and velocities of 1 and 1.5 m/s using rectangle shaped potato and apple slices (12.5 × 12.5 × 25 mm) and cylindrical shaped pumpkin slices (35 × 5 mm). The temperature changes of the dried crops and the temperature of the drying air were measured during the drying process. It was found that the values of convective heat transfer coefficient varied from crop to crop with a range 30.21406 and 20.65470 W/m 2 C for the crops studied, and it was observed that the convective heat transfer coefficient increased in large amounts with the increase of the drying air velocity but increased in small amounts with the rise of the drying air temperature.

Local vortices in a differentially rotating flow

A time-dependent local elliptic vortex in a differential two-dimensional incompressible fluid flow is considered. Nonlinear oscillations of vortices of the cyclonic and anticyclonic types are described. It is found that the evolutionary tracks can be both closed and unclosed. The former correspond to the azimuthal oscillations of the principal axis and the latter to the complete rotational state of the elliptic vortex. Steady-state solutions are also obtained; they are represented by ellipses elongated or compressed along the flow. Small oscillations of the vortex equilibrium figures are investigated and a general dispersion relation for arbitrary perturbations is derived. The stability criterion is found.

乾式サイクロンの局所的な流動制御による分級性能の向上

The present work studied the effectiveness of secondary flow injection into a cyclone on the separation performance of sub-micron particles. The particle collection efficiency increased with the secondary flowrate when injected in the upper cylindrical section of the cyclone. It was found that high particle collection efficiency is attained when the injection location of the secondary flow is close to the upper plate at a high flow velocity. A new type of cyclone developed based on these results achieved a high collection efficiency, which was in qualitative agreement with the three-dimensional simulation results.

On the relationships between circulation types and changes in rainfall variability in Greece

AbstractAn attempt is made to examine rainfall variability over the Greek area in relation to 500 hPa atmospheric circulation. Daily precipitation series from 22 evenly distributed Greek stations have been used for the period 1958–2000, along with the classification scheme of daily circulation types at 500 hPa for the same period. The seasonal frequency and the trends of circulation types have been calculated. It was found that there is a general positive trend of anticyclonic circulation types and a negative one for cyclonic types. The seasonal trends of rainy days and the precipitation totals have also been calculated and analysed. A general decreasing tendency of winter rainfall is observed; the decreasing trend during autumn and spring is less significant. Concerning the frequency and intensity of rainfall per circulation type, a decreasing tendency becomes evident for the majority of the stations during winter, whereas there is an increasing tendency during autumn. A multiple regression–cross‐validation model was developed using the seasonal frequency of circulation types as predictors and the seasonal rainfall totals as predictants. Only the winter modelled precipitation shows a good agreement with the observed precipitation, whereas for the other seasons the agreement is relatively poor. This could be caused by the influence of different factors that are not captured by the classification scheme used. The proposed model could serve as a circulation‐based downscaling method that could be further applied to geopotential data available from general circulation models in order to study regional climatological consequences of future climate scenarios. Copyright © 2004 Royal Meteorological Society

A Synoptic Climatology of the Subtropical Kona Storm

Ten years of surface and upper-air analyses from the ECMWF Tropical Ocean Global Atmosphere (TOGA) dataset were used to construct a synoptic climatology of kona storms in the subtropical central and eastern Pacific Ocean. Within a sample of 115 cyclones that predominantly occurred during the Northern Hemisphere cool season, three distinct types of kona storms were identified: cold-frontal cyclogenesis (CFC) cyclones, coldfrontal cyclogenesis/trade wind easterlies (CT) cyclones, and trade wind easterlies (TWE) cyclones. Of the three types, CFC cyclones were found to be the most common type of kona storm, while CT and TWE cyclones occur much less frequently. The geographical distribution, propagation characteristics, and the monthly and interannual variability in the number of kona storms are presented. Kona storms initially develop across a large portion of the subtropical Pacific, with the greatest concentration of kona storms found within a southwest-to-northeast-oriented band from west of Hawaii to 408N, 1408W. A distinct latitudinal stratification was evident for each type of kona storm, with CFC, CT, and TWE cyclones each more likely to initially develop at successively lower latitudes. The analysis reveals that kona storms can propagate in any direction but exhibit a clear preference to propagate toward the northeast. Use of the multivariate ENSO index indicates that the number of kona storms that develop during each cool season is not correlated to the phase of ENSO. An analysis of the composite structure and evolution of each type of kona storm revealed some common and some unique characteristics. Development of the surface cyclone in all types results from the intrusion of an upper-level disturbance of extratropical origin into the subtropics, although differences in the initial structure and subsequent evolution of the 300-hPa trough were noted for each type of kona storm. The analysis also revealed that relatively weak 300-hPa winds are present throughout the evolution of each type of kona storm and that the composite kona storm tends to be nestled along the southern boundary of a region of higher surface pressure during the mature stage of its evolution. The development of robust ridges in the 300-hPa geopotential and 1000‐500-hPa thickness fields downstream of the composite surface cyclone were noteworthy features that characterized the evolution of all kona storms, the latter feature strongly suggesting that these disturbances are fundamentally baroclinic in nature.

Effect of mist injection position on particle separation performance of cyclone scrubber

Experimental and simulation studies have been conducted about the effect of mist injection position on particle separation performance of cyclone scrubber. The typical particle trajectories for the normal type cyclone are calculated. The optimum mist injection position is determined based on the simulation of particle trajectories. Two types of cyclone scrubbers that have different mist injection position were tested in this research. It was found that the particle separation efficiency is strongly depended on the mist injection position. With the injection of mist, the 50% cut size is smaller than the case with the injection of air only. It was also found that increasing liquid to gas flow ratio enhances the separation efficiency. The experimental data agreed with the numerical simulation based on the direct flow calculation method.

Spatial Analysis of Extreme Precipitation in Sweden 1961–2000

Extreme daily precipitation in Sweden for the years 1961-2000 is analyzed with respect to spatial scale, regional variations and associated weather types. Correlograms based on a lag distance of 30 km estimated the spatial scale of variation of the annual mean precipitation, the 99th percentile of daily precipitation and the average of annual maximum daily precipitation to 100 km, 60-100 km and 40-70 km, respectively. Regions of correlation with respect to precipitation at 82 stations during days of extreme events are identified through Maximum-Likelihood Factor Analysis. Eleven factors are found to provide the optimum factor solution. Weather types for the days of extreme events are determined by an objective classification scheme, based on daily sea level pressure, which is modified by subjective inclusion of fronts. In total, 63% of the extreme events occurred during cyclonic weather types, 32% during frontal, 3% during directional and 2% during anticyclonic types. The frequency of the weather types during extreme events varied between the regions however.

MODELING and EXPERIMENTAL STUDY ON DRYING of APPLE SLICES IN A CONVECTIVE CYCLONE DRYER

ABSTRACTThe main objective pursued in this paper is to experimentally investigate the single layer drying behavior of apple slices in a convective type cyclone dryer and also to perform the mathematical modeling by using single layer drying models in literature. the experiments were conducted at drying air temperatures of 60, 70 and 80C in drying air velocities of 1 and 1.5 m/s. It was concluded that apple slices with the thickness of 12.5 mm would perfectly dry in the ranges of 280–540 mm while those with the thickness of 8 mm would dry in the ranges of 180–320 min in these drying conditions by using convective type cyclone dryer. Additionally, the mathematical model describing the single layer drying curves was determined by nonlinear regression analysis, and the logarithmic model was selected as the most suitable model to obtain the drying curve equation of apple slices. Considering the parameters such as drying time, drying rate, moisture transfer, velocity and drying air temperature it is suggested that the apple slices be dried at the above optimum processing conditions.

Effects of flow and geometrical parameters on the collection efficiency in cyclone separators

A mathematical model has been developed for calculation of cut-off size and fractional efficiencies in cyclone separators, by taking into account the effects of flow, particle and geometrical parameters, and acceleration assuming that the mixture of fluid and particles is homogenous, and acceleration diminishes depending on the friction and geometry. Collection efficiency curves and cut-off size values predicted by the proposed model showed a good agreement with experiments over a wide range of inlet velocities for different types of cyclones. Comparison of the obtained results with semi empirical models available in literature also indicated that the present model may be used successfully for determination of the performance of a tangential inlet cyclone. Analyses of the effects of various parameters reveals that, in addition to flow and geometrical parameters, surface friction, vortex length and flow regimes play an important role on cyclone performance especially in small cyclones.

大型油回収船「白山」の油回収システムについて

Hakusan is the oil recovery vessel for the open sea. This ship was planned to build because of the oil spill of oil tanker Nakhodka when it sank in January 1997.We decided to load the oil recovery system “the cyclone type”. However the cyclone type was difficult to collect the oil in the winter high wave and to collect the very sticky oil.Accordingly we developed the new type of the oil recovery system that was based on model-experiment.And the oil recovery vessel “Hakusan” which was loaded the most suitable oil recovery system completed in August 2002.

Мезомасштабні та мікрофізичні властивості смуг хмар та опадів фронтальної системи циклону вибухового поглиблення над Антарктичним півостровом

The study is focused on the numerical simulation of frontal rainbands associated with a deep depression of the explosive cyclone type, moved over the Antarctic Peninsula from the South Pacific and caused severe weather and heavy precipitation 01-02.04.98. To study the formation and development of supercooled frontal rainbands, the adaptation of previously worked out numerical models to the specific region with limited initial data both for the simulation and verification of the model outputs has been performed. Outputs of 3-D novacasting limited area model (LAM) based on rawinsonde data of Bellingshausen station are used as initial data for 1-D forecasting microphysical model. A set of equations is used to simulate the evolution of the processes of condensation, nucleation, freezing, sedimentation, accretion, collection, etc. Thermodynamical conditions in the troposphere are continuously updated as the system moved over the initial point in 1-D simulation. Two tracks via the frontal rainbands are studied. The study shows that at the same thermodynamic conditions the liquid phase of the precipitation formed only by coagulation processes less depends on the concentrations, while the solid phase changes dramatically when the concentrations varying, in particular, over the Antarctic Peninsula. The study has pointed extreme values of cloud microphysical empirical parameters and showed that frontal clouds moved from the Pacific to the West Antarctic undercertain conditions can accumulate the huge reserve of precipitable moisture that could result in heavy rain and snowfalls.

Optimization of the evaporation cavity in a torch integrated sample introduction system based ICP-AES system. Applications to matrix and transient effects, analysis of microsamples and analysis of certified solid samples

Results corresponding to the optimization of the aerosol evaporation cavity of the previously published torch integrated sample introduction system (TISIS) are shown in the present work. A micronebulizer (i.e., MicroMist) operated at liquid delivery rates in the 20–200 µl min−1 range was used throughout. Theoretical calculations suggested that the TISIS chamber allowed the evaporation of a significant fraction of the solvent contained in primary aerosol, while the remaining droplets first impacted against its inner walls and then evaporated. The cavity dimensions (i.e., length and inner diameter) were optimized in terms of sensitivity and memory effects. The results demonstrated that the longer the cavity, the higher the sensitivity, whereas an increase in its diameter did not significantly modify the aforementioned parameters. The optimized TISIS cavity, with a conical shaped end, proved to significantly shorten the wash-out times with respect to a double pass spray chamber and a low inner volume cyclonic type one (i.e., a Cinnabar spray chamber). Besides, the TISIS was used for discrete sample introduction of very low sample volumes (i.e., from 0.3 to 32 µl). The peaks found were narrower and higher than those provided by a double pass spray chamber. Matrix effects caused by sodium, acetic acid and ethanol solutions were less severe for TISIS than for the double pass and the Cinnabar spray chambers, while transient effects caused by nitric acid solutions almost disappeared when using the TISIS. As a result of the mitigation of the interferences, the recoveries found for three certified solid samples while calibrating with plain water standards were closer to 100% for the TISIS than for double pass and mini cyclonic spray chambers.

Analysis issues for cyclone

Cyclone [1, 2] is an experimental, type-safe programming language based upon the syntax, semantics, and spirit of C. The primary goal of the language is to provide a type-safe environment that is close enough to C in both appearance and functionality, that systems programmers will find it attractive and useful.The most challenging aspect of the design is capturing the spirit of C without compromising type-safety. In particular, systems programmers expect to have good control over data representations, memory management, and performance. Yet, these features are usually absent from high-level, type-safe languages (e.g., Java). Another challenge is validating a sufficiently wide set of idioms that are in fact type-safe, but which conventional type systems reject.To address these issues, we have used a novel combination of typing features in conjunction with some interesting inference and dataflow techniques. The most novel typing feature is the support for region-based memory management which was summarized in an earlier paper [1]. However, this paper did not discuss the inference techniques we use to validate the regions and effects.In this talk, I will briefly summarize the Cyclone type system and then focus on the analysis issues that arise in its implementation, including (a) kind and type inference, (b) region and effect inference, and (c) dataflow analysis for validating initialization, array subscripts, and linear pointers.

Single layer drying behaviour of potato slices in a convective cyclone dryer and mathematical modeling

The main objective pursued in this paper is to investigate the single layer drying behaviour of potato slices experimentally in a convective cyclone dryer and also to perform mathematical modeling by using single layer drying models in the literature. Drying experiments of potato slices with the thicknesses of 12.5 and 8 mm were conducted at inlet temperatures of drying air of 60, 70 and 80 °C and with drying air velocities of 1 and 1.5 m/s. It was concluded that potato slices with thickness of 12.5 mm would dry perfectly in the range of 460–740 min, while those with thickness of 8 mm would dry in the range of 280–520 min in these drying conditions in the convective type cyclone dryer. Additionally, the mathematical model describing the single layer drying curves was determined by non-linear regression analysis, and an approximation of the diffusion model was selected as the most suitable model to describe the drying curve equation of potato slices.

Norwegian-Type and Cold Front Aloft–Type Cyclones East of the Rocky Mountains

Abstract Conventional data and mesoscale model simulations are used to analyze two cyclones that developed east of the Rocky Mountains in June and November 1998. Both cyclones formed when a Pacific cold front overtook a lee trough/dryline east of the Rockies. In one case the leading edge of the Pacific cold front was on the surface, as depicted in the classic Norwegian model of a cyclone. In the other case, which is referred to as a cold front aloft (CFA) cyclone, the leading edge of the Pacific cold front was aloft and in advance of the lee trough. The lifting and severe weather associated with the Pacific cold front was along the leading edge of this front in both the Norwegian-type and CFA-type cyclones. To obtain an estimate of how often CFA cyclones, with a coincident CFA rainband, occurred in the central United States during the period 15 September 1994 through 15 September 1995, 70 cyclones that maintained closed surface low pressure centers for at least 24 h, and produced precipitation in the Unit...

Predicting the performance of air cyclones

Many empirical models for predicting the particle separation efficiency of cyclone separators have been presented by different investigators, but they are often limited in their use to the particular type of cyclones on which they were developed. This paper describes theoretical models and a numerical model for the analysis of the fluid flow and particle separation of cyclones and how they may be used in the design of new types of cyclones. The governing fluid and particulate flow equations have been analysed and numerically solved in order to predict the fluid flow and particle separation in cyclones. In addition, the key design parameters for the cyclones have been discussed as to their effect on the overall performance of the cyclone and general recommendations for the engineering design of cyclones have been suggested. Copyright © 2002 John Wiley & Sons, Ltd.

A classification of FASTEX cyclones using a height‐attributable quasi‐geostrophic vertical‐motion diagnostic

AbstractA systematic and objective procedure is developed for applying the simple cyclone classification scheme of Petterssen and Smebye. This method uses a height‐attributable solution of the quasi‐geostrophic ! equation to identify and quantify the relative importance of upper‐ and lower‐tropospheric forcing and also the time trend in the horizontal spacing of the forcing at these two levels. By applying this classification method to a sample of cyclogenesis events, during their maximum intensification stage, from the Fronts and Atlantic Storm‐Track EXperiment field experiment, the Type A and Type B scheme of Petterssen and Smebye is reproduced and extended to include a Type C. Type C consists of upper‐level dominated cyclones that form at high latitudes and in their initial stages resemble comma‐cloud‐type polar lows. Detailed examples of each of the three types are presented. Some cyclones can undergo more than one period of development and it is found that each development period can be classified as a different cyclogenesis category, A or B: these cyclones are classified as hybrid Type A=B. There is some evidence that cyclone forecast accuracy depends on cyclone type, thereby suggesting the potential for this method to be used to assign confidence levels for forecasts of cyclogenesis produced by numerical weather‐prediction models. Type B cyclones appear more difficult to predict, because their development depends, initially, on the interaction between significant features in the upper and lower troposphere. Copyright © 2002 Royal Meteorological Society. T. D. Hewson's contribution is Crown copyright.

New torch design with an in-built chamber for liquid sample analysis by ICP-AES

The analytical performance of the torch integrated sample introduction system (TISIS) for the analysis of very low sample volumes by ICP-AES is described. The TISIS consists of a commercially available torch with a low inner volume cavity (i.e., 5–9 cm3) placed at its base, which is attached to the shortened plasma injector tube through a special PTFE adapter. The nebulizer is vertically fitted to the torch base by means of a home-made Teflon adapter that has an exit for the drain solution. The aerosol is thus generated at the base of the TISIS cavity. The nebulization conditions corresponded to very low liquid flow rates (i.e., from 5 to 200 µl min−1) and conventional gas flow rates (i.e., 0.7 l min−1). Based on previously published work, these nebulization conditions favored aerosol solvent evaporation. At ambient temperature and below 40 µl min−1, almost all the solvent was evaporated and no drain was needed. Therefore, the main purpose of the TISIS cavity was to promote efficient solvent evaporation (instead of selecting the maximum drop size introduced into the plasma) and to simplify the transport path. In order to enhance solvent evaporation, the primary aerosols must be as fine as possible. In the present work, two pneumatic micronebulizers were employed: a so-called high efficiency nebulizer (HEN) and a MicroMist. For the sake of comparison, the HEN was coupled to a double-pass spray chamber and the MicroMist to a cyclonic type spray chamber. The results indicated that the TISIS exhibited promising behavior in ICP-AES, giving rise to emission intensities similar to or higher than both conventional reference systems. No further deterioration of the plasma thermal characteristics was observed when using the TISIS with respect to conventional chambers. The signal stability and limits of detection were similar for the different systems employed.

CLIMATOLOGICAL CLASSIFICATION OF SEVERE WIND-DRIVEN RAIN EVENTS AFFECTING THE SOUTHERN UNITED STATES

This paper follows recent studies of wind-driven rain (WDR), and statistically defines a “severe” WDR event. The research suggests a classification for severe WDR events by association with larger-scale weather systems. The study incorporates data for the period 1971 to 1995 and, from these data, the analysis reveals that severe WDR events are confined mainly to the southern United States and occur most frequently in the cold and transition seasons. Extratropical cyclones are the most common synoptic-scale weather systems associated with severe WDR events. Extratropical cyclones originating in three areas accounted for more than 70 percent of the severe events in the study. The cyclone types are referred to as Colorado Lows (CLs), Gulf Lows (GLs), and Texas Lows (TLs). The attendant synoptic-scale conditions of cyclones that produced severe WDR events differ significantly from extratropical cyclones originating in similar areas but not producing severe events. Key differences between the two cyclone populations are the cyclone track trajectories and the low and midlevel synoptic environments promoting cyclone intensification. [Key words: wind-driven rain (WDR), synoptic climatology, extratropical cyclones, United States.]