Extra Air Research Articles

BCM Municipal Wastewater Advanced Treatment New Technology

BCM (Biology Cilium Magnetic) technology is a kind of municipal wastewater advanced treatment technology. By using high elastic cilia filler in the oxygen unit, the volume loading of oxygen unit has been greatly increased, and more solubility pollutants could be removed in the oxygen unit. The total phosphorus and suspended substance are deeply removed by magnetic separation coagulation system. The effect of BCM technology is that all pollutants indexes could reach to the first level A standard of GB18918-2002. BCM technology is suitable for AA/O, oxidation ditch and SBR process which needs to be upgraded from the first level B to the first level A standard. The high elastic cilia filler in oxygen unit doesn’t require extra land and extra air. The magnetic separation coagulation system only needs very small land. So BCM technology is suitable for municipal wastewater treatment in China.

Investigation of electrostatic charge distribution within the reactor wall fouling and bulk regions of a gas–solid fluidized bed

Abstract The distribution of charge within the wall fouling region and bulk of a fluidized bed reactor was investigated. Experiments were conducted in a 0.1 m in diameter carbon steel fluidization column under atmospheric conditions. Polyethylene particles were fluidized with extra dry air at 1.5 the minimum fluidization velocity (bubbling flow regime) for 1 h. Using an online Faraday cup measurement technique, the net charge-to-mass ratio ( q / m ), as well as the size distribution of all particles adhered to the column wall and those in the bulk of the bed was determined. The wall particles were found to be predominantly negatively charged while those which did not adhere to the wall were predominantly positively charged. The charge distribution within each region was then investigated by a custom made charged particle separator that separated the particles according to their charge magnitude and polarity. It was determined that although the net charge of the wall layer particles was negative, a significant amount of positively charged particles existed within each sample and therefore the entire wall particle layer. This suggests that the wall layer was formed through layering between positively and negatively charged particles. Particles in the bulk of the bed also consisted of bipolarly charged particles.

MIPAS-STR measurements in the Arctic UTLS in winter/spring 2010: instrument characterization, retrieval and validation

Abstract. The mid-infrared FTIR-limb-sounder Michelson Interferometer for Passive Atmospheric Sounding–STRatospheric aircraft (MIPAS-STR) was deployed onboard the research aircraft M55 Geophysica during the RECONCILE campaign (Reconciliation of Essential Process Parameters for an Enhanced Predictability of Arctic Stratospheric Ozone Loss and its Climate Interactions) in the Arctic winter/spring 2010. From the MIPAS-STR measurements, vertical profiles and 2-dimensional vertical cross-sections of temperature and trace gases are retrieved. Detailed mesoscale structures of polar vortex air, extra vortex air and vortex filaments are identified in the results at typical vertical resolutions of 1 to 2 km and typical horizontal sampling densities of 45 or 25 km, depending on the sampling programme. Results are shown for the RECONCILE flight 11 on 2 March 2010 and are validated with collocated in-situ measurements of temperature, O3, CFC-11, CFC-12 and H2O. Exceptional agreement is found for the in-situ comparisons of temperature and O3, with mean differences (vertical profile/along flight track) of 0.2/−0.2 K for temperature and −0.01/0.05 ppmv for O3 and corresponding sample standard deviations of the mean differences of 0.7/0.6 K and 0.1/0.3 ppmv. The comparison of the retrieved vertical cross-sections of HNO3 from MIPAS-STR and the infrared limb-sounder Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere–New Frontiers (CRISTA–NF) indicates a high degree of agreement. We discuss MIPAS-STR in its current configuration, the spectral and radiometric calibration of the measurements and the retrieval of atmospheric parameters from the spectra. The MIPAS-STR measurements are significantly affected by continuum-like contributions, which are attributed to background aerosol and broad spectral signatures from interfering trace gases, and are important for mid-infrared limb-sounding in the Upper Troposphere/Lower Stratosphere (UTLS) region. Taking into consideration continuum-like effects, we present a scheme suitable for accurate retrievals of temperature and an extended set of trace gases, including the correction of a systematic line-of-sight offset.

Multi-Objective Approach in Exergoeconomic and Environmental Optimization of the Gas Turbine Cycle

The gas turbine cycle either as an individual power production cycle or as a part of yet another cycle, is one of the most common industrials till now which, has been ever evaluated and analyzed. In the present research, this cycle has been modeled individually along with a pre-heater and a compressor at two stages with the objective to maximize the exergic efficiency and in the meantime decreasing the costs and environmental pollution. In addition, the isentropic turbine efficiency, the isentropic compressor efficiency, the ratio of the total pressure of the cycle, and the percentage of extra air has been defined as the design variables. Two objective functions are evaluated to be optimized by the genetic algorithm using the Pareto fitness approach as the determining comparison function. Finally, the exergo-economic coefficient of the related components and the amount of their exergy destruction and cost, at the optimum point, has been compared.

Comparison of the effect of grounding the column wall in gas-solid fluidized beds on electrostatic charge generation

In gas-solid fluidized beds as particles are fluidized, they continuously come into contact with other particles, as well as the fluidization column wall. This generates electrostatic charges by means of triboelectrification and frictional charging, leading to particle agglomeration, reactor wall fouling, and eventually process downtime and large financial losses. Grounding the fluidization column has been considered as a means of helping electrostatic charge dissipation within fluidized beds; however, in industrial applications despite the process vessels being grounded, the electrostatic problem still persists. This work focused on the effect of fluidization column grounding on particle wall fouling. Experiments were conducted in an atmospheric system consist of a 0.1 m in diameter carbon steel fluidization column. The mass and charge-to-mass ratio (q/m) of the particles that remained adhered to the column wall upon the completion of one hour fluidization period were measured in an electrically isolated and grounded columns to quantitatively determine the amount of reactor wall fouling. Polyethylene particles with different particle size ranges (300– 1000 μm) were fluidized with extra dry air at 1.5 times their respective minimum fluidization velocity (umf). Results obtained in the grounded fluidization column were not significantly different from those in the isolated column for all particle size ranges tested where the particles mass collected and q/m and were found to be generally similar.

Simulation of Thermoset Injection for Bulk Moulding Compounds (BMC)

This paper discusses about the simulation of the process of injection moulding for thermoset materials namely Bulk Moulding Compounds (BMC). BMC is a polyester resin based compound with glass fibre additives. In this paper a complex part was used to simulate and obtain the parameters for moulding BMC. Autodesk Moldflow Plastics Insight was used to run the simulation. Two main parameters i.e. Injection time and mould temperature were considered. Six different sets of parameters were used and the settings were optimized. The obtained optimized settings are 15.08 seconds and 145°C. The obtained parameters were then applied and the actual part was tested using an injection-moulding machine. After the simulation, changes were also made to the actual mould to improve the moulding conditions. Extra air vents were added at the problematic areas to ease the flow. There was an average variance of 7% which was thought to be acceptable as the simulation considers the ideal condition, where as there may be external factors such as the machine wear and tear during the actual moulding of the part. It can be said that the simulation was run successfully and tested during actual moulding.

Engineering of geranylgeranyl pyrophosphate synthase levels and physiological conditions for enhanced carotenoid and astaxanthin synthesis in Xanthophyllomyces dendrorhous

The basidiomycetous yeast, Xanthophyllomyces dendrorhous, is one of the very few organisms which can be used for biological production of the carotenoid astaxanthin. crtE cDNA has been cloned from this fungus for engineering of the terpenoid pathway. The function of its gene product as a geranylgeranyl pyrophosphate synthase was established. X. dendrorhous was transformed with the crtE cDNA to divert metabolite flow from the sterol pathway towards carotenoid biosynthesis. Transformants were obtained with increased levels of geranylgeranyl pyrophosphate synthase leading to higher carotenoid levels including astaxanthin. Physiological conditions for maximum carotenoid synthesis for wild type and the CrtE transformant were dim light and extra air supply of the shaking culture. These conditions and the transformation with crtE had additive effects and resulted in an 8-fold higher astaxanthin formation as compared to the initial wild type culture without illumination and extra air supply yielding 451 μg/g dry wt within 4 days of growth.

Quasi-steady-state and steady-state models for heat and moisture transport in textile assemblies

Heat and moisture transport plays an important role in many engineering areas. In many sweat transport systems, such as clothing assembly, the moisture concentration (or sweat) is relative small and the air concentration reaches a steady state quickly. In this paper, a quasi-steady-state multi-component and multi-phase model for heat and moisture transport in porous textile materials with phase change is proposed. An analytic form of the air concentration is obtained in terms of the mixture gas (vapour and air) concentration and temperature. The new model is described in the form of a single-component flow with an extra air resistance (permeability), involving only the vapour concentration (or pressure), temperature and water content. The existence of the classical positive solutions of the corresponding steady-state model is proved. Two types of clothing assemblies are investigated numerically. The comparisons among the experimental measurements and numerical results of the fully dynamic model, the proposed quasi-steady-state model and steady-state model are also presented. Numerical results show that the proposed quasi-steady-state model is realistic and less complicated.

Effect of sampling in the evaluation of particle size distribution in nanoaerosols

The isokinetic sampling procedure is adopted to avoid errors in important parameters (particle concentration, collection efficiency, etc.) in aerosol studies. To attain isokinecity in a given sampling can be costly or difficult to control. This study aims at evaluating the behavior of nanometric particles in the laminar aerosol flow for various conditions of non-isokinetic sampling. Polydispersed sodium chloride (NaCl) particles dispersed in an extra pure air current were used as a test aerosol. The analysis was based on comparisons of size distribution measurements of the particles collected using different sampling nozzles and v 1/ v 2 ratios (i.e. between the velocity in the main duct, v 1, and at the nozzle, v 2). The results show that the size distribution was an independent ratio, for a given sampling nozzle. Also, the sampling size distribution did not depend on the ratio between the diameter of the sampling nozzle and that of the main flow duct in the system. Based on these findings, it can be concluded that, within the particle size range of 12.0–130.0 nm, duct Re < 600, duct/sampling velocity ratio ( v 1/ v 2) ranging from 0.28 to 6.25 and small particle Stokes number (St') ranging from 2.7 × 10 − 7 to 1.1 × 10 − 5, the effects of non-isokinetic sampling at the particle size distribution are negligible.

Don't Hold Your Breath

Competitive breath-holders can float face down in a pool for more than 4 minutes, and the world record is 11 minutes 35 seconds. That can't be good for their brains, right? To find out, researchers at Lund University in Sweden had nine trained breath-holders lie face-up on a couch and hold their breath to mimic the so-called static apnea pool competition. The breath-holders started with their normal warm-up routines: hyperventilation and “lung packing” (using tongue and throat muscles to force extra air into the lungs). Then they stopped breathing for an average of 5.5 minutes. The volunteers' blood oxygen levels dropped by almost 80%, and concentrations of the protein S100B—a standard marker for brain damage—increased by 37%, the researchers reported online 2 July in the Journal of Applied Physiology . S100B is normally found inside brain cells and fluid but seeps into the bloodstream when an injury disrupts the brain's protective blood-brain barrier. The breath-holders' concentrations were lower than those seen in stroke or traumatic brain injury patients, and the levels recovered after 2 hours. “We probably only saw a temporary opening of the blood-brain barrier,” says researcher Johan Andersson, but he warns that it is unclear if repeated barrier openings might produce long-term brain damage. Ralph Potkin, a pulmonologist at the Beverly Hills Center for Hyperbaric Medicine in Los Angeles, California, calls the findings “disconcerting.” But John Fitz-Clarke, a diving physiologist at Dalhousie University in Halifax, Canada, says that “it's way too premature to draw any conclusions about brain damage” from these findings.

Pump out the volume—The effect of tracheal and subelytral pressure pulses on convective gas exchange in a dung beetle, Circellium bacchus (Fabricus)

Many flightless beetles like the large apterous dung beetle Circellium bacchus, possess a subelytral cavity (SEC) providing an extra air space below the elytra which connects to the tracheal system (TS) via metathoracic and abdominal spiracles. By measuring subelytral and intratracheal pressure as well as body movements and gas exchange simultaneously in a flow-through setup, we investigated the contribution of convection on Circellium respiratory gas exchange.No constriction phase was observed. TS and SEC pressures were always around atmospheric values. During interburst phase open abdominal spiracles and a leaky SEC led to small CO2-peaks on a continuous CO2 baseline, driven by intermittent positive tracheal pressure peaks in anti-phase with small negative subelytral pressure peaks caused by dorso-ventral tergite action.Spiracle opening was accompanied by two types of body movements. Higher frequency telescoping body movements at the beginning of opening resulted in high amplitude SEC and TS pressure peaks. High frequency tergite movements caused subelytral pressure peaks and led to a saw tooth like CO2 release pattern in a burst. We propose that during the burst open mesothoracic spiracles increase the compliance of the subelytral cavity allowing big volumes of tracheal air being pulled out by convection.

Effect of cathode microstructure on arc velocity and erosion rate of cold cathodes in magnetically rotated atmospheric pressure arcs

Atmospheric pressure arc velocity and arc erosion measurements were performed on thermal sprayed copper cathodes having grain size distributions from submicrometre to a few micrometres in a continuous running arc system. Ultrahigh purity (UHP), 99.99% pure, argon and a mixture of UHP argon with 10% (volumetric) extra dry air were used as plasma forming gases. An external magnetic field of 0.10 T was used to rotate the arc which was operated at a constant power setting of 6 kW (150 A and 40 V). Cathodes having different microstructures were formed using high velocity oxygen fuel (HVOF) spraying and vacuum plasma spraying (VPS) methods with different annealing times. HVOF sprayed cathodes were tested for arc erosion and arc velocity in their as-sprayed state and also after annealing them at 300 and 600 °C for 1 and 8 h durations in an inert argon atmosphere. VPS sprayed coatings were tested as-sprayed. The effect of the initial coating thickness on erosion rates was investigated. Annealing HVOF coatings at 600 °C for 8 h produced near equi-axed grains with a 2–3 µm average size. These coatings showed 60% higher steady state arc velocities and up to 68% lower erosion rates compared with massive copper cathodes having a 20–23 µm average grain size. VPS coatings having a 0.9–1.5 µm average grain size gave up to 70% lower erosion rates when compared with massive copper cathodes. The results show a clear effect of the cathode microstructure on the arc velocity and the erosion rate.

Air transport liberalisation and traffic growth in tourism-dependent economies: A case-history of some US-Caribbean markets

This study looks at the relationship between air traffic/capacity growth and recent air policy reform pertaining to some Caribbean member states. The hypothesis is tested that changes to extra regional air policy can facilitate traffic growth that may result in substantial tourism growth for the region. A time-trend evaluation for three US-Caribbean markets shows that the country-pair which did not make efforts to further liberalise free carrier designation rights between 1995 and 2003 saw less traffic/capacity growth as those that had. The number of competitors, along with low-cost carrier expansion, has increased more notably on US-Bahamas markets than on US-Dominican Republic and US-Jamaica markets. A non-linear air traffic model, modified to include an intuitive liberalisation scale, is used to better reflect the fragmented approach towards air policy development. It is found that a unit increase in air policy liberalisation produced annual log traffic growth coefficients of between 2.55% and 3.02% with the upper estimate affected least by multicollinearity within the US-Bahamas traffic model. These findings challenge current restrictive practises in the region.

Are You Smarter Than a Fifth Grader?

Of course you are. If you are reading this column, you are most likely a college-educated, twenty-first-century information professional who is engaged in assisting members of your community navigate through, find, and understand complex information resources. This takes skills far beyond those of a fifth-grade education. So why am asking? At the time of the writing of this column, a new television game show was rising in popularity. For those of you who stay out of touch with current popular culture or who may be reading this in future years long after this particular show has been cancelled, it is based upon an interesting premise. Hosted by Jeff Foxworthy (who despite his blue collar, redneck humor is a graduate of Georgia Tech and was formerly employed by IBM), adults compete against a team of fifth-grade students to answer factual questions compiled from grade school textbooks. Questions are rated in difficulty from the first through fifth grade. Topics are grouped in categories ranging in supposedly increasing levels of difficulty, from first-grade science to third-grade spelling to fifth-grade geometry. Answering all of the questions correctly results in a reward of $1,000,000, whereas failing to complete that task requires the adult to say: I am not smarter than a fifth grader. Needless to say, the producer's money at the Fox network is pretty safe, and most adults end up admitting their ignorance. Admittedly, the show picks some pretty smart fifth graders to compete against the adults. The children answer the questions correctly much more frequently than the adults do, and there is obvious joy when they get the answers right. In fact, at least one member of the current cast has already demonstrated the potential to become a future RUSA member. The children's desire to show off their intelligence by matching wits with adults is refreshing, demonstrating to other young people that learning is not only cool, but that it can literally pay off with some big money. The fact that the adults can cheat off the kids lends an extra air of respect to the children, although it also sends the negative message that cheating on tests is acceptable behavior. Overall, the program takes knowledge of basic facts and turns it into some pretty good entertainment As a reference librarian, this program has caught my attention for a number of reasons. The idea that adults who have presumably completed their K-12 schooling cannot beat a group of fifth graders on a quiz show says something about our society The fact that we--that I--actually watch such programming probably says even more. And the fact that most adults fail to correctly answer all of the questions says something about how we measure the success and failure of information queries. The entire success of this show depends on measuring intelligence through correct or incorrect answers to factual questions. Although the nature of the questions is a little different, the process sounds a lot like the popular image of reference service. As with Katherine Hepburn in the 1950s film Desk Set, people come to the library with questions and librarians find answers. As in that film, some questions might be easy, such as finding the names of Santa's reindeer. Some are more difficult, such as determining whether the King of the Watusis drives an automobile (and, if so, what make and model). In this version of reference service, the librarian serves as the definitive, correct arbitrator of factual information. This is very often the popular image of the reference librarian. However, it is not the reality. With the development of the Internet and such Web tools as Yahoo! and Google, people are able to find accurate factual information on their own. …

Comparison of thermal comfort performance of two different types of road vehicle climate control systems

The performance of climate control systems in vehicles becomes more and more important, especially against the background of the important relationship between compartment climate and driver mental condition and, thus, traffic safety. The performance of two different types of climate control systems, an un-air-conditioned heating/cooling device (VW) and an air-conditioning climate control unit (BMW), is compared using modern and practical evaluation techniques quantifying both the dynamic 3-D temperature distribution and the local air refreshment rate. Both systems suffer from considerable temperature gradients: temperature gradients in the U-AC (VW) car up to 8–9°C are encountered, while the AC (BMW) delivers clear improvement resulting in temperature gradients of 5–6°C. The experiments clearly demonstrate the effect of the presence of even a single passenger on the thermal regime, increasing the existing thermal discrepancies in the compartment with 15% independent of ventilation rate. Furthermore, in terms of air refreshment rates in the vehicle compartment, an air-conditioning unit halves the air refreshment time at all positions in the vehicle cabin, delivering a significant improvement in terms of human comfort. Similarly, extra air inlets in the back compartment of a car deliver progress in terms of cabin refreshment rate (93 s down to 50 s).

Bandgap properties of modified square photonic crystal fibers

The bandgap properties of modified square photonic crystal fibers are investigated. It is shown numerically that the bandgaps of such fibers can be tailored by introducing an extra air hole into the center of each unit cell of the original square lattice. Square photonic crystal fibers with large air holes can be designed to be air-guiding by introducing extra air holes of about the same size. The air-guiding regions of square photonic bandgap fibers with extremely large air holes can also be greatly extended by the extra air holes.

Bandgap properties of Kagomé photonic crystal fibers

Photonic crystal fibers (PCFs) can guide light by the photonic bandgap (PBG) effect created by the periodically arranged air holes in the cladding. In this paper, the bandgap properties of Kagome photonic crystal fibers (KPCFs) are investigated in detail. First, the bandgap properties of PCFs based on the basic Kagome lattice are analyzed and compared with the PBGs of PCFs based on honeycomb and triangular lattices. We highlight the similarities between KPCFs and honeycomb PCFs in their PBGs, both having air-guiding regions only at very large air filling fractions (AIFs), whereas the PBGs of triangular PCFs can have large air-guiding regions at smaller AIFs due to the difference in the gap structure. In the second half of this paper, we show how the PBGs of KPCFs can be modified by introducing an extra air hole into the vacant space of the original lattice. In particular, KPCFs with medium-sized air holes can be designed to guide air by introducing extra air holes of a larger size. The air-guiding regions of KPCFs with very large air holes can also be greatly extended by the extra air holes. These air-guiding regions occur at higher normalized frequencies, resulting in larger air hole pitches favorable for fabrication.

Emission Rates Due to Indoor Activities: Indoor Aerosol Model Development, Evaluation, and Applications

This study presents an indoor aerosol model based on size-resolved and multi-compartment approach. The current indoor aerosol model is also developed with a semi-empirical technique to estimate the emission rates due to indoor sources of aerosol particles. We present in this study a methodology to predict and estimate the best-fit input parameters for the current indoor aerosol model. The performance of the current indoor aerosol model in its single-compartment form was evaluated against previously measured indoor-outdoor aerosol data sets from an office room with mechanical ventilation and a family house with natural ventilation. The indoor aerosol model simulations show that the current methodology used to predict the best-fit input parameters to the indoor aerosol model is efficient. As expected, the penetration factor, aerosol particle deposition, and ventilation rate are the most important parameters in the indoor-outdoor relationship of aerosol particles transport. The emission rate analysis showed that fine aerosol particles production was as high as 26 particle/cm 3 s during wood burning in a fireplace. The emission rate was about eight times this value during grilling in a fireplace and sauna heating. Indoor activities take place in another room may significantly increase the aerosol particle concentrations in other rooms in the building. Therefore, it is recommended to use extra air cleaners in houses to reduce the number concentrations of emitted aerosol particles. The quantitative and qualitative results obtained by the current indoor aerosol model in this study are building and condition specific. Applying the current model to a broad range of conditions and previously measured indoor-outdoor aerosol data sets provides better understanding of aerosol particle characteristics indoors, especially regarding the aerosol particles produced during different indoor activities.

Use of catalytic reforming to aid natural gas HCCI combustion in engines: experimental and modelling results of open-loop fuel reforming

The potential of the homogeneous charge compression ignition (HCCI) combustion process to deliver drastically reduced emissions of NO x and improved fuel economy from internal combustion engines is well known. The process is, however, difficult to initiate and control, especially when methane or natural gas are used as fuel. To aid the HCCI combustion of natural gas, hydrogen addition has been successfully used in this study. This hydrogen can be obtained from on-line reforming of natural gas. Methane reforming is achieved here by reaction with engine exhaust gas and air in a small scale monolith catalytic reactor. The benchmark quantity of H 2 required to enhance the feasibility and engine load range of HCCI combustion is 10%. For low temperature engine exhaust gas, typical for HCCI engine operating conditions, experiments show that additional air is needed to produce this quantity. Experimental results from an open-loop fuel exhaust gas reforming system are compared with two different models of basic thermodynamic equilibria calculations. At the low reactor inlet temperatures needed for the HCCI application (approx. 400 ∘ C ) the simplified three-reaction thermodynamic equilibrium model is in broad agreement with experimental results, while for medium ( 550 – 650 ∘ C ) inlet temperature reforming with extra air added, the high hydrogen yields predicted from the multi-component equilibrium model are difficult to achieve in a practical reformer.

The extraordinary events of the major, sudden stratospheric warming, the diminutive antarctic ozone hole, and its split in 2002

Great interest in the unprecedented events of the major, sudden stratospheric warming and the ozone hole split over Antarctica in September 25, 2002 motivates a necessity to analyze the current understanding on the dynamics, chemistry and climate impacts that are associated with both events. Significant progress in the analysis of the observational data obtained, as well as successful development and application of dynamical modeling, which have been achieved very recently, create a basis for the first survey on the role of the major, sudden stratospheric warming observed in the southern hemisphere and its relationship to the diminutive Antarctic ozone hole and its break up into two parts. Special attention has been paid to assessments of the causes of the major warming event and the future expectations concerning the stratospheric ozone depletion effect. Among the principal results is the fact that, as the polar vortex elongated, it became hydrodynamically unstable, and this insta-, bility affected the upper troposphere and stratosphere. During the major, sudden stratospheric warming, the middle stratospheric vortex split into two pieces; one piece rapidly mixed with extra vortex air, while the other returned to the pole as a much weaker and smaller vortex. The polar night jet was considerably weaker than normal, and was displaced more poleward than has been observed in previous winters, resulting from a series of wave events (propagated from the troposphere) that took place over the course of the winter. Finally, the relative ozone decrease (increase) in the eastern Antarctic is tightly associated with westerly (easterly) zonal wind anomalies near the southern tip of South America, and the unusual behavior of the ozone hole in 2002 therefore appears to be caused by great easterlies in this region. The main conclusion is that the southern polar vortex and the diminutive ozone hole split into two parts in September 2002, due to the prevalence of very strong planetary waves, led to the appearance of a major, sudden stratospheric warming. Although there is evidence that sea surface temperature anomalies contributed to the excitation of the quite strong planetary waves over Antarctica in 2002, there is not yet a widely approved mechanism supporting that. The appearance of the near-record size of the 2003 ozone hole confirmed that the 'no-ozone-hole' episode observed in the year 2002 does not denote a recovery of the ozone layer. Despite the current successful attempts to get a sufficient understanding for the genesis of both extraordinary events, more observations and further modeling efforts are necessary to more reliably assess the contribution of various dynamic mechanisms to the recently observed tropo-stratospheric surprises.