Three-point observation in the troposphere over Sofia-Plana Mountain,Bulgaria

Based on a novel combination of approaches and instruments, this article presents campaign-based results from atmospheric boundary layer (ABL) height and aerosol optical depth (AOD) measurements carried out at two different experimental sites in Sofia, as well as from three-point measurements of aerosol number concentrations. Several instruments (lidar (developed by the IE), ceilometer, aerosol particle counter, sun photometer and meteorological sensors) were used in this study. Based on joint interpretation of the instruments' data we assess the influence of the atmospheric aerosol in the planetary boundary layer and the significant influence of aerosol layers and high clouds on AOD values. Measurements of AOD in the city basin gave values in the range 0.22–0.41 for cloud-free skies, and up to around 0.8 under partly cloudy conditions. The information obtained during the two campaigns indicates that aerosol particle concentrations were lower in park areas than along heavy-traffic thoroughfares in the city, but higher than in the mountain area. In conclusion, our study demonstrates the potential of employing a broad array of instruments for the study of boundary layer and aerosol over large, valley-situated and heavily urbanized city areas.     

Boundary layer development and meteorological parameters impact on the ground level ozone concentration over an urban area in a mountain valley (Sofia,Bulgaria)

The ecological problems caused by the increasing ozone concentration are not easily solved because ozone is not directly emitted by certain sources Its concentration depends on numerous dynamical and chemical processes. Stratosphere–troposphere exchange and subsequent ozone penetration into the boundary layer determine the contribution of so-called ‘natural’ ozone to ozone pollution near the ground. However, the main contribution to the concentration of this pollution is that of the anthropogenic ozone, which is generated as a result of complex photochemical reactions. The purpose of this research is the ground level ozone concentration behaviour to be studied during the stable boundary layer (SBL) and the residual layer (RL) destruction and the convective boundary layer (CBL) formation, so the influence of the temperature, the relative humidity and the height of the mixing layer (ML) as well as that of the ML formation in different areas of Sofia (42° 39′ N, 23° 23′ E, 591 m above sea level), Bulgaria, have to be determined. The ground level ozone concentration in the area of the Institute of Electronics changes synchronously with the development of the ML. The maximum values of the ground level ozone concentration are reached when the height of the ML reached its maximum and afterwards. The maximum growth of the ground level ozone concentration is around 11:00–12:30 h LST when a fast growth of the ML begins and the complete destruction of the RL is observed, that is, the two processes of ML growth and entrainment of aerosol and ozone from the higher layers of the atmospheric boundary layer are observed. The values of the ground level ozone concentration during the summer months are higher than those during the fall.     

Experimental Designs Optimally Balanced for Trend

When experiments are carried out over a period of time, the response may be subject to time trends. We use an algorithm for exact optimum designs to construct a series of designs resistant to linear and quadratic trend. Designs considered include the allocation of simple treatments, multifactor designs in qualitative or quantitative factors, and response surface designs. The investigation is extended from consideration of linear ordering in time to include designs with several trials at each time point, designs in which several trials are spread over only one out of three shifts per day, and designs in which there are more time points than experiments. Comparisons with designs in the absence of trend show that surprisingly little information is lost by designing for protection against a potential trend. The BT algorithm for obtaining these designs is outlined.     

The endoscopic therapy of benign stenoses of the esophagus and cardioesophageal junction using Eder-Puestow instrumentation

The results of palliative endoscopic treatment by bougienage using Eder-Puestow instrumentation, performed in a limited contingent of patients presenting benign esophageal strictures, are analyzed. It is underscored that the method is readily carried out and effective, and seldom leads to noteworthy complications, such as esophageal perforations--one patient alone presenting cicatricial stricture out of the total of 42 cases given treatment with bougienage over a 10-year period. The commonest cause of benign strictures of the esophagus in the series being examined is reflux (peptic) esophagitis against the background of hiatus hernia.     

Introduction of a new continuous time and state space stochastic process in condition prediction

Periodic condition assessments of pavements together with condition predictions are the basis for investment decisions in every pavement management system (PMS). Typical approaches include surveys of distress types every 3–6 years with analysis rating and calculation of condition indices for road safety and/or structural health. Furthermore, advanced PMS prediction models allow a comparison of maintenance alternatives and an optimisation of investment strategies. This paper presents an overview of current survey and rating approaches in Germany, Switzerland and Austria, together with an impact analysis of different methods, utilised deterministic performance functions and condition threshold (trigger) values for all major distress types. The core of this paper is a comparison of common deterministic condition prediction models with discrete stochastic approaches and prediction models based on advanced regression techniques mainly from scientific literature and an innovative stochastic continuous time and continuous state space process (HOFFMANN – Process). All prediction models are applied to real-world data from condition surveys in Austria and the long-term pavement performance Database (USA) at single-section and network level. The paper provides evidence why deterministic prediction approaches are leading to substantial bias in condition distribution and remaining service life as they do not account for the stochastic nature of pavements. Classic Markov-chain approaches do not account for censoring of survey data and neglect changes in transition probabilities with increasing age. Applying common bivariate and multiple regression techniques may also lead to certain bias due to collinearity effects and specification bias. The paper provides mathematical evidence on ways to avoid these shortcomings based on the presented innovative stochastic process leading to a higher reliability in condition assessment, rating and accuracy of condition predictions. The aspects of censoring, distress-specific assignment and optimisation of treatments with this new HOFFMANN-process will be covered in forthcoming papers.     

Substrate effects on the electron-beam-induced deposition of platinum from a liquid precursor

Focused electron-beam-induced deposition using bulk liquid precursors (LP-EBID) is a new nanofabrication technique developed in the last two years as an alternative to conventional EBID, which utilizes cumbersome gaseous precursors. Furthermore, LP-EBID using dilute aqueous precursors has been demonstrated to yield platinum (Pt) nanostructures with as-deposited metal content that is substantially higher than the purity achieved by EBID with currently available gaseous precursors. This advantage of LP-EBID--along with the ease of use, low cost, and relative innocuousness of the liquid precursors--holds promise for its practical applicability in areas such as rapid device prototyping and lithographic mask repair. One of the feasibility benchmarks for the LP-EBID method is the ability to deposit high-fidelity nanostructures on various substrate materials. In this study, we report the first observations of performing LP-EBID on bare and metal-coated silicon-nitride membranes, and compare the resulting Pt deposits to those obtained by LP-EBID on polyimide membranes in terms of nucleation, morphology, size dependence on electron dose, and purity.