Ambient Surfaces Research Articles

Modelling Europe-wide fine resolution daily ambient temperature for 2003–2020 using machine learning

To improve our understanding of the health impacts of high and low temperatures, epidemiological studies require spatiotemporally resolved ambient temperature (Ta) surfaces. Exposure assessment over various European cities for multi-cohort studies requires high resolution and harmonized exposures over larger spatiotemporal extents. Our aim was to develop daily mean, minimum and maximum ambient temperature surfaces with a 1 × 1 km resolution for Europe for the 2003–2020 period. We used a two-stage random forest modelling approach. Random forest was used to (1) impute missing satellite derived Land Surface Temperature (LST) using vegetation and weather variables and to (2) use the gap-filled LST together with land use and meteorological variables to model spatial and temporal variation in Ta measured at weather stations. To assess performance, we validated these models using random and block validation. In addition to global performance, and to assess model stability, we reported model performance at a higher granularity (local). Globally, our models explained on average more than 81 % and 93 % of the variability in the block validation sets for LST and Ta respectively. Average RMSE was 1.3, 1.9 and 1.7 °C for mean, min and max ambient temperature respectively, indicating a generally good performance. For Ta models, local performance was stable across most of the spatiotemporal extent, but showed lower performance in areas with low observation density. Overall, model stability and performance were lower when using block validation compared to random validation. The presented models will facilitate harmonized high-resolution exposure assignment for multi-cohort studies at a European scale.

Validating HONO as an Intermediate Tracer of the External Cycling of Reactive Nitrogen in the Background Atmosphere.

In the urban atmosphere, nitrogen oxide (NOx═NO + NO2)-related reactions dominate the formation of nitrous acid (HONO). Here, we validated an external cycling route of HONO and NOx, i.e., formation of HONO resulting from precursors other than NOx, in the background atmosphere. A chemical budget closure experiment of HONO and NOx was conducted at a background site on the Tibetan Plateau and provided direct evidence of the external cycling. An external daytime HONO source of 100 pptv h-1 was determined. Both soil emissions and photolysis of nitrate on ambient surfaces constituted likely candidate mechanisms characterizing this external source. The external source dominated the chemical production of NOx with HONO as an intermediate tracer. The OH production was doubled as a result of the external cycling. A high HONO/NOx ratio (0.31 ± 0.06) during the daytime was deduced as a sufficient condition for the external cycling. Literature review suggested the prevalence of high HONO/NOx ratios in various background environments, e.g., polar regions, pristine mountains, and forests. Our analysis validates the prevalence of external cycling in general background atmosphere and highlights the promotional role of external cycling regarding the atmospheric oxidative capacity.

Chemometric and risk assessment of nitrogen composition of atmospheric rainwater from diverse surfaces in Rivers State, Nigeria.

Organic and inorganic nitrogen ions in the environment play important role across environmental matrices. Rainwater samples collected from ambient and different roofing surfaces (zinc, aluminium, asbestos and stone-coated roofing sheets) from selected locations at Ogale, Rumuodomaya/Rumuodome, Diobu and Chokocho within Rivers State, Niger Delta, Nigeria, from April to June, July to August and September to October depicting three regiments of early, mid and late rains. The samples were analysed for Kjeldahl nitrogen, ammonium, nitrate and nitrite using APHA methodology. Quantitative assessment showed that Kjeldahl nitrogen were in range of 0.11 to 28.05mg/L; ammonium 0.50 to 20.22mg/L, nitrate from 0.12 to 22.69mg/L and nitrite from 0.15 to 3.90mg/L. Parameters decreased from early to late rain, which can be attributed to rain dilution factor potential, wind pattern and emission from anthropogenic sources that influenced the rainwater quality across surfaces. Nitrogen results showed that dry and wet deposition has great impact; atmospheric aerosols and biogeochemical interactions can affect water quality. Monthly variation showed that Ogale had high regression compared to other locations due to close proximity to oil and gas emission and marine contribution. Neutralization factor showed that nitrate-nitrite compounds have strong correlation with ammonium ion. Non-carcinogenic risk assessment using US EPA model showed hazard index less than one (1), thus no associated health effect of nitrate and nitrite in rainwater. In conclusion, it is evident that nitrate/nitrite levels and other nitrogen derivatives in rainwater in crude oil-producing Niger Delta and its continuous consumption can cause negative health outcome.

Spatial and Temporal Audience Behavior of Scrum Practitioners Around Semi-Public Ambient Displays

Exploring spatial and temporal audience behavior around ambient displays is an important area of HCI research. It aids in, for instance, understanding better user appropriation in natural environments. However, there are only a few tools to capture said behavior, and simultaneously, little knowledge of the space around ambient display installations exists. In this research, we report on audience behavior observed during an in-the-wild study where we deployed our custom Ambient Surfaces solution in a professional, large-scale agile software development context for circa 5 years. Across 18 weeks in 2017, we collected skeletal data with two Microsoft Kinect v2 cameras resulting in behavior information of more than 30,000 passersby. Our results indicate, among others, that users did show the highest levels of engagement at quite some distance to the Ambient Surfaces and that people engaging in direct interaction did so rather purposely. Ultimately, this article encapsulates our research’s originality in four contributions including an approach to separate passersby from real users and an in-depth exploration of skeletal data. With the tools and methods illustrated, we hope to demonstrate manifold insights for future research on audience behavior tracking.

Spontaneous Utilization: A Classic Grounded Theory of Utilizing Ambient Displays in Professional, Large-Scale Agile Software Development Environments

ABSTRACT This research addresses an interdisciplinary problem area concerning the long-term deployment of socially embedded technology in authentic environments. It concentrates on the case of ambient displays, where long-term research in the real world is still scant and evidentially requires methodological development. This study seeks to advance on this situation at both findings and methodological levels. To this end, we introduce our Ambient Surfaces solution that was deployed in the agile software development department of a company for circa 5 years. Classic grounded theory was chosen to methodologically guide the evaluation, while the theoretical contribution of this work is a substantive theory exemplified by its core category of Spontaneous utilization. The theory reveals insights on how ambient displays are utilized by practitioners in professional and large-scale agile environments. We found, among others, that staff members used the Ambient Surfaces largely not on purpose, that our solution evolved toward having a strong emphasis on progress tracking information, and that inter-team awareness as well as intra-team communication were encouraged.

Elucidating molecular mechanisms of two-dimensional chemical reactions

Elucidating molecular mechanisms of two-dimensional chemical reactions

Euler characteristics of Gothic Teichmüller curves

We compute the Euler characteristics of the recently discovered series of Gothic Teichm\"{u}ller curves. The main tool is the construction of 'Gothic' Hilbert modular forms vanishing at the images of these Teichm\"{u}ller curves. Contrary to all previously known examples, the Euler characteristic is not proportional to the Euler characteristic of the ambient Hilbert modular surfaces. This results in interesting 'varying' phenomena for Lyapunov exponents.

ANALYSIS OF PRESSURE AND VELOCITY EFFECTS OF ACOUSTIC WAVES ON DIFFERENT AMBIENT SURFACES USING FDTD METHOD

Bu çalışmada ses dalgalarının farklı ortam yüzeylerinde meydana getirdiği basınç ve hız değişimleri ele alınmıştır. Ultrason dalgalarına benzerliği nedeniyle çalışmada ses dalgaları kullanılmıştır. Dalga modeli olarak, gauss nabız dalga modeli kullanılmıştır. Ortam yüzeyleri olarak hava, su, metal, s-oil, polietilen gibi cansız yüzeyler, doku türleri da olarak bağ doku ve kas dokusu yüzeyleri analizlerde kullanılmıştır. Seçilen bu ortam yüzeylerinde, akustik dalgalarının oluşturduğu basınç etkileri, zamanda sonlu farklar (FDTD) metodu kullanılarak incelenmiştir. Örneklenen gauss ses dalgasının analizinde, iterasyon sayısı arttıkça yayılım değeri de artmaktadır. Polietilen yapılı katmanlarda ise sesin oluşturduğu basıncın etkisinin düşük olduğu (Pplastik=39,5 µPa ve Vplastik=13,17 µm/sn ) tespit edilmiştir. Canlı dokulardan bağ dokusu ve kas dokusu üzerinde yapılan incelemede ise bir ses dalgasının bu iki doku üzerinde benzer basınç (Pbağ=1,295 Pa, Pkas=1,282 Pa) ve hız (Vbağ=0,63 µm/sn, Vkas= 0,58 µm/sn) değerleri oluşturduğu gözlenmektedir.

خنک سازی محیطهای شهری و تأثیر آن بر تغییرات اقلیمی در محلات سنتی و سکونتگاههای غیررسمی از طریق آسایش حرارتی بیرونی (نمونه موردی محلات عاملی ، قلعه ساختمان و شهرک حجت شهر مشهد)

خنک سازی محیطهای شهری و تأثیر آن بر تغییرات اقلیمی در محلات سنتی و سکونتگاههای غیررسمی از طریق آسایش حرارتی بیرونی (نمونه موردی محلات عاملی ، قلعه ساختمان و شهرک حجت شهر مشهد)

Real Algebraic Curves on Real del Pezzo Surfaces

AbstractThe study of the topology of real algebraic varieties dates back to the work of Harnack, Klein, and Hilbert in the 19th century; in particular, the isotopy-type classification of real algebraic curves in real toric surfaces is a classical subject that has undergone considerable evolution. On the other hand, not much is known for more general ambient surfaces. We take a step forward in the study of topological-type classification of real algebraic curves on non-toric surfaces focusing on real del Pezzo surfaces of degree 1 and 2 with multi-components real part. We use degeneration methods and real enumerative geometry in combination with variations of classical methods to give obstructions to the existence of topological-type classes realized by real algebraic curves and to give constructions of real algebraic curves with prescribed topology.

Antimicrobial Resistance as a Problem for the Quality of Boar Semen

Abstract The aim of the study was to determine whether the bacteria from the environment and from the mucous membrane of the boar prepuce have antimicrobial resistance and whether the result obtained is similar/same to the bacteria that can be found in native boar semen. The study addresses the problem of the presence of primarily resistant bacterial strains in the boar sperm, which, due to their reduced sensitivity, cannot be suppressed by antibiotics used in the semen dilution agent, as well as to emphasize the importance of microbiological monitoring of the boar mucous membranes and ambient surfaces before and during their exploitation. Such an examination could contribute to the interchangeable design of the dilution agent for the boar semen relative to the antibiotic content.Resistant strains of bacteria from prepuce swabs and swabs taken from the facility, as well as from native boar semen were isolated. The presence of these bacteria affected the quality of the semen. In conclusion, it should be pointed out that bacterial monitoring of the prepuce and surface of the facility can indicate possible problems related to the quality of semen, and that the design of the dilution agent for boar semen should be adjusted to the established resistance of isolated bacteria.

Sessile Droplet Freezing on Hydrophobic Structured Surfaces under Cold Ambient Conditions.

There have been conflicting reports as to whether surface wettability is effective in the freezing delay enhancement of attached water droplets. It is an important problem in the development of anti-icing surfaces needed for applications, such as aircraft wings and infrastructures. Here, we prepared precooled ambient conditions and surfaces which included smooth, microstructured, and two nanostructured surfaces with hydrophobic coatings to create an environment closer to the actual environment and to avoid frost formation, which enhances wetting transition and nucleation. Static and dynamic wetting characteristics of each surface were investigated as the fundamental properties and the freezing behavior of precooled water droplets were observed. A distinct elongation of the freezing delay time was observed for droplets on nanostructured surfaces which have static contact angles >150°, in contrast to those on smooth and microstructured surfaces. However, the difference in droplet adhesion induced by nanostructures showed a negligible impact on freezing delay. These results indicated that the reduction of the actual contact area between the solid and liquid phases restricted ice nucleus formation.

The first gap for total curvatures of planar graphs with nonnegative curvature

AbstractWe prove that the total curvature of a planar graph with nonnegative combinatorial curvature is at least 1/12 if it is positive. Moreover, we classify the metric structures of ambient polygonal surfaces for planar graphs attaining this bound.

Dynamic gas flow effects on the ESD of aerospace vehicle surfaces

An aerospace vehicle traveling through the atmosphere is subject to triboelectrically induced electrostatic charge build-up caused by dust and ice crystal impingement. Electrostatic discharges between an antenna housing and the exterior of the vehicle may interfere with system operation. Paschen's Law, derived for stationary, charged surfaces, fails to account for the loss of electron-ion pairs with high gas velocity between the electrodes. The purpose of this work is to develop a version of Paschen's Law that takes into account the flow of ambient gas past electrode surfaces. The basic hypothesis of this work is that the number of electron-ion pairs created per unit distance between electrode surfaces is mitigated by the electron-ion pairs removed per unit distance by the flow of gas. The revised theoretical model must be a function of the mean velocity, vxm, of the ambient gas and reduce to Paschen's law when the gas mean velocity, vxm = 0. This model has been evaluated by wind tunnel experimentation. Initial data of the baseline wind tunnel experiments show results consistent with the hypothesis. Based on the results of this work, it is hoped that the safety of aerospace vehicles will be enhanced with a redefinition of electrostatic launch commit criteria. It is also possible that new products, such as anti-static coatings, may be formulated from this data.

Wet nitrogen and phosphorus deposition in the eutrophication of the Lagos Lagoon, Nigeria.

Air pollution is influenced by wind-aided particulate suspension, open-air waste burning, and fossil fuel combustion. The pollutants from these sources eventually deposit on ambient surfaces. Atmospheric wet deposition into Lagos Lagoon may be significant additions to the nutrient levels of the eutrophic lagoon. Precipitation was monitored at three stations in the Lagos Lagoon basin from May to November, 2012, in order to estimate the contribution of wet deposition to the nutrient cycles of the lagoon. Water samples were digested with potassium persulfate, and the species of phosphorus (P) and nitrogen (N) were analyzed by colorimetric methods. The mean [NO3-+NO2-]-N level was 0.39±0.51kgha-1month-1. The average total N was 3.16±6.39kgha-1month-1. The mean soluble reactive P was lower than the [NO3-+NO2-]-N averaging 0.06±0.09 (at control site S2) to 0.24±0.10kgha-1month-1 (at site S1). Average total P was 1.25±0.82kgha-1month-1. The annual total N (May-September) was 4.55 (at S2) to 32.4kgha-1year-1 (at S3). The annual total P (May-November) over Lagos Lagoon basin was 5.06kgha-1year-1 (at S2). This study demonstrated that wet deposition of anthropogenically derived nutrients to the Lagos Lagoon is ongoing and may represent a considerable proportion of the total nutrient loading to it. The increased P availability in the wet deposition is likely responsible for the water hyacinths, which usually blossom on Lagos Lagoon during the late rainy season, and the reported harmattan-season bottom water hypoxia.

Low frequency dove coos vary across noise gradients in an urbanized environment

Urbanization poses a challenge to bird communication due to signal masking by ambient noise and reflective surfaces that lead to signal degradation. Bird species (especially oscines) have been shown to alter their singing behaviour to increase signal efficiency in highly urbanized environments. However, few studies on the effects of noise on song structure have included birds with low frequency vocal signals which may be especially vulnerable to noise pollution due to significant frequency overlap of their signals with traffic noise. We compared the perch coos of spotted doves (Streptopelia chinensis), a species with very low frequency vocalizations, in different background noise levels across urban and peri-urban areas in Hong Kong. We documented a 10% upward shift in the minimum frequency of coos of spotted doves across the noise gradient (a relatively small but significant shift), and a reduced maximum frequency in urban habitats with a higher density of built up area. Hong Kong doves had significantly higher minimum and maximum frequencies than doves from throughout their range (from mostly rural sites). Our results indicate that urban species with extremely low sound frequencies such as doves can alter their vocalizations in response to variable urban acoustic environments.

Adaptive digital fringe projection technique for high dynamic range three-dimensional shape measurement.

It is a challenge for any optical method to measure objects with a large range of reflectivity variation across the surface. Image saturation results in incorrect intensities in captured fringe pattern images, leading to phase and measurement errors. This paper presents a new adaptive digital fringe projection technique which avoids image saturation and has a high signal to noise ratio (SNR) in the three-dimensional (3-D) shape measurement of objects that has a large range of reflectivity variation across the surface. Compared to previous high dynamic range 3-D scan methods using many exposures and fringe pattern projections, which consumes a lot of time, the proposed technique uses only two preliminary steps of fringe pattern projection and image capture to generate the adapted fringe patterns, by adaptively adjusting the pixel-wise intensity of the projected fringe patterns based on the saturated pixels in the captured images of the surface being measured. For the bright regions due to high surface reflectivity and high illumination by the ambient light and surfaces interreflections, the projected intensity is reduced just to be low enough to avoid image saturation. Simultaneously, the maximum intensity of 255 is used for those dark regions with low surface reflectivity to maintain high SNR. Our experiments demonstrate that the proposed technique can achieve higher 3-D measurement accuracy across a surface with a large range of reflectivity variation.

Is the pulsed xenon ultraviolet light no-touch disinfection system effective on methicillin-resistant Staphylococcus aureus in the absence of manual cleaning?

Methicillin-resistant Staphylococcus aureus (MRSA) has been shown to survive on ambient surfaces for extended periods of time. Leftover MRSA environmental contamination in a hospital room places future patients at risk. Manual disinfection supplemented by pulsed xenon ultraviolet (PX-UV) light disinfection has been shown to greatly decrease the MRSA bioburden in hospital rooms. However, the effect of PX-UV in the absence of manual disinfection has not been evaluated. Rooms that were previously occupied by a MRSA-positive patient (current colonization or infection) were selected for the study immediately postdischarge. Five high-touch surfaces were sampled, before and after PX-UV disinfection, in each hospital room. The effectiveness of the PX-UV device on the concentration of MRSA was assessed employing a Wilcoxon signed-rank test for all 70 samples with MRSA in 14 rooms, as well as by surface location. The final analysis included 14 rooms. Before PX-UV disinfection there were a total of 393 MRSA colonies isolated from the 5 high-touch surfaces. There were 100 MRSA colonies after disinfection by the PX-UV device and the overall reduction was statistically significant (P < .01). Our study results suggest that PX-UV light effectively reduces MRSA colony counts in the absence of manual disinfection. These findings are important for hospital and environmental services supervisors who plan to adapt new technologies as an adjunct to routine manual disinfection.

General Parametrization of Persisting Long-Range Nanoscale Phenomena in Force Measurements Emerging under Ambient Conditions

Advances in quantification of nanoscale forces are mainly focused on repulsive forces, the sample’s stiffness, and related parameters such as deformation. The reactivity and chemistry of the surface however depends on longer range forces that are prevalent in ambient conditions and control functional surfaces. Suitable models and appropriate parametrization of this range, however, are still emerging. Here, we define and employ metrics to parametrize long-range forces and experimental observables in dynamic atomic force microscopy and force measurements in a general way even when suitable physical models are lacking. We find that plateaus in the attractive part of the force that can be of more than 1 nm in range are a general characteristic of surfaces exposed to the ambient environment. These plateaus can be identified directly from force measurements or indirectly from computationally low-cost parameters that we define here. We further demonstrate that the defined metrics can be employed for rapid discri...

In situ bioconjugation and ambient surface modification using reactive charged droplets.

Molecular ions are generated in induced electrospray ionization, and they can be transported to grounded ambient surfaces in the form of charged microdroplets. Efficient amide bonds formation between amines and carboxylic acids were observed inside charged droplets during transfer to the surface. Biomolecules derivatized using this method were self-assembled on a bare gold surface via Au-S bonds under the charged microdroplet environment. Cyclic voltammetric analysis of the self-assembled molecular film showed accelerated protein derivatization with cysteine, which allowed the covalent immobilization of the protein to the gold surface. Cytochrome C-functionalized electrodes prepared using the induced dual nanoelectrospray process showed bioactivity toward aqueous solutions of hydrogen peroxide below 50 μM. In effect, we have developed a method that allows derivatization of biomolecules and their immobilization at ambient surfaces in a single experimental step.