Grassy Surface Research Articles

Impact of paving surface material on thermal conditions within a residential building

This paper presents the impact of paving surface material on thermal comfort in a residential building. The aim of the study was to demonstrate differences in temperature, measured near a building’s walls, depending on their location (relative to the cardinal directions) and the type of paving surface material outside the building (in its immediate vicinity, considering the cardinal directions). The study found differences in temperature values recorded near walls located on the south-west side, which faced a garden and a grassy surface, compared to the temperature of the walls that faced a street with asphalt and concrete paving blocks. It should be noted that the study was carried out in the summer, when the interior of the building was not heated. The facade of the building had not been additionally insulated and retained its original historical form (facade render). The method used in the study consisted of temperature measurements taken near the building’s walls using a Steinberg System weather station’s sensors. The measurement results supported the hypothesis that wall temperature varies depending on a space’s placement relative to the cardinal directions and the surface paving material in the space adjoining the building. The results of the study are presented using line graphs. The study is of scientific value and the results may also be useful in site development planning practice. The thermal conditions are a major factor that affecting the comfort of various types of buildings, including housing.

Identification and Quantification of Surface Depressions on Grassy Land Surfaces of Different Topographic Attributes Using High-Resolution Terrestrial Laser Scanning Point Cloud and Triangulated Irregular Network

The objective of this study was to identify and quantify surface depressions on grass-covered land surfaces using a high-resolution terrestrial laser scanning (TLS) point cloud, and a triangulated irregular network (TIN). The entire grassy land surface in the study area was divided into five subwatersheds of different topographic attributes (i.e., depression depth and surface slope). Surface depressions were identified and quantified using a TIN generated from a high-resolution TLS point cloud. The results indicated that microtopography of the grassy land surface was well-characterized within each subwatershed in comparison with field observations. With the terrestrial light detection and ranging (LIDAR) point cloud of 15-mm point spacing and the TIN method, surface depression storage depths of the five subwatersheds ranged from 1.73 to 14.28 mm in the study area. The surface depression storage depth, as expected, increased with the maximum depth of surface depression. It was also found to increase when the land surface slope became milder. A sensitivity analysis indicated that a point cloud with a point spacing of 30 mm was sufficient to obtain an accurate representation of the terrain surface in the study area. This study also indicated the TIN method can represent the ground surface and the surface depression more realistically than the commonly used digital elevation model (DEM) method due to the TIN method’s higher capability of identifying and filtering out surface obstructions such as blades of grass. Moreover, by using the high-resolution TLS technology and the TIN method, our study provides an important and broad range of reference data on the surface depression storage depth commonly needed in application of the Storm Water Management Model (SWMM) and other watershed models.

ANALISIS KONDISI PERKERASAN JALAN DENGAN METODE BINA MARGA DAN PAVEMENT CONDITION INDEX (PCI)

Highways are one of the infrastructures to accelerate the growth and development of an area, especially the Klungkung Regency. Due to the age of the road pavement plan, the road service level will decrease. If this condition is left unchecked, it will worsen the condition of the pavement layers and the costs required will increase. Therefore, it is necessary to analyze the road damage so that later it can determine the maintenance and handling program. In writing this analysis using qualitative methods, data on road damage conditions was carried out by visual surveys, on the Kutapang-Maos road section, with the length of the road being observed along 1,200 km from km 0+000 - km 1+200. The categories of types of damage reviewed are cracking, patches and holes, surface hardness, grooves, and subsidence. While the existing condition of the pavement width is 3 meters, the pavement thickness is 5 cm with the AC layer, and the last overlay was carried out in 2009. The condition of the road shoulders is 1.5 – 2 meters wide with a grassy surface. In the analysis of the types of damage raveling, alligator cracking, patching, longitudinal and transverse cracking, shoving, potholes, ruts, and grade depressions with the Bina Marga method analysis, the priority order value is 8 while the PCI method analysis gets the road condition value is 6, meaning the road is included in moderate condition level (Fair) and the order of priority is 9 so that the appropriate alternative type of maintenance is a routine maintenance program. The form of handling the damage is with Burtu, Burda, and Lapen, while the costs required are Rp. 27,702,395.00-

Escoamento de drenagem sobre terreno ondulado

The present work investigates drainage events of cold air that occur over an undulating terrain, with elevations differences of some tens meters and grassy surface. For this, data collected in the autumn of 2015 from a micrometeorological tower and four weather stations are used. The results show two different cases of drainage, one when the ambient flow is upslope against the near the surface drainage flow, and another when the ambient flow is downslope in favor of the drainage.

Formation of grassy TiO2 nanotube thin film by anodisation in peroxide electrolyte for Cr(VI) removal under ultraviolet radiation

Arrays of TiO2 nanotubes (TiO2 NTs) with grassy surfaces were observed on titanium foil anodised at 60 V in fluorinated ethylene glycol (EG) with added hydrogen peroxide (H2O2). The grassy surface was generated by the chemical etching and dissolution of the surface of the TiO2 NTs walls, which was accelerated by the temperature increase on the addition of H2O2 . Upon annealing at 600 °C, the grassy part of the TiO2 NTs was found to consist of mostly anatase TiO2 whereas the bottom part of the anodic oxide comprised a mixture of anatase and rutile TiO2. The TiO2 NTs were then used to reduce hexavalent chromium (Cr(VI)) under ultraviolet radiation. They exhibited a rather efficient photocatalytic effect, with 100% removal of Cr(VI) after 30 min of irradiation. The fast removal of Cr(VI) was due to the anatase dominance at the grassy part of the TiO2 NTs as well as the higher surface area the structure may have. This work provides a novel insight into the photocatalytic reduction of Cr(VI) on grassy anatase TiO2 NTs.

Variability and role of long-wave radiation fluxes in the formation of net radiation and thermal features of grassy and bare soil active surfaces in Wrocław

The paper examines the variability of long-wave radiation fluxes in two contrasting types of urban active surfaces – grassy surface and surface without plants (bare soil) in Wrocław (Poland) within a 12-year period (August 2007–July 2019). The study used net radiation and heat balance formulas to calculate the share of individual radiation fluxes in these balances, and then utilized the Stefan-Boltzmann formula to calculate the effective temperatures of researched surfaces. The analysis showed the temporal variability of these fluxes against the background of weather and climatic conditions and in relation to the variability of short-wave radiation fluxes. The role of long-wave radiation fluxes in forming net radiation was examined in detail to show the buffering role of vegetation surfaces regarding the variability of solar radiation fluxes and their heat effects. The mean monthly values of outgoing long-wave radiation fluxes change from 309.0 W·m−2 for bare soil, 309.8 W·m−2 for grassy surface, and 288.8 W·m−2 for downward atmospheric radiation to respectively 435.8, 425.0 and 369.4 W·m−2 in July. The coefficient of variability for long-wave radiation daily fluxes are approximately one order of magnitude lower than for the short-wave radiation. The differences between values of long-wave radiation fluxes for bare soil and grassy surfaces vary from slight negative values in winter to relatively sizable positive values during the vegetation period (March–October). The weakening of the buffering effect for grassy surface and how air temperature then changes considerably compared to the effective temperature of the active surfaces were explained using the dry summer period of August 2015 as example. The obtained results are important, as they provide empirical arguments for urban planning to extend plant areas' share in big cities as well as to introduce there a friendly environmental system of irrigation in these areas using renewable solar energy.

Long-wave radiation balances of grassy surface and bare soil in Wrocław

The paper goal is to show diurnal, seasonal and year to year variability of long-wave radiation balances of two contrasting types of active surfaces – grassy and bare soil in the context of bioclimatic and ecological role of plant areas in a big city. The analyses was conducted on example of Wrocław (SW Poland) and the experimental results were obtained from about twelve-year period of measurements. The average annual values of fluxes of the main components of these long-wave balances reached: 368.6 W/m2 for the long-wave radiation of bare soil, 363.6 W/m2 for the long-wave radiation of grassy surface and 322.9 W/m2 for the downward atmospheric radiation. These differences between values of bare soil and grassy surfaces varied during the year from negative values in winter to positive values in spring and the summer. The final conclusion of the study is an important empirical argument for urban planning to extend share of plant areas in cities and urban agglomerations.

Subsurface shallow depth soil layers thermal potential for ground heat pumps in Poland

Subsurface shallow depth soil layer (SSDSL) is characterized by dynamic temperature changes, which may be eligible to constitute as a heat source for ground heat pumps. This paper aims to present the regime of heat flow in SSDSL and its climatic conditions in central Europe, taking into consideration the agriculture periphery characteristics of Wroclaw (Poland). Emphasis was laid on the relation between the radiative properties and heat balance of two contrasting types of analyzed active surfaces (bare soil and grassy surface). The obtained experimental results gathered across a span nine years (August 2007–July 2016) and the conducted thermal analysis aim to evaluate the utilization of SSDSL as a heat source for ground heat pumps. The heat fluxes were measured between the active surface of the soils and their lower layers on an 8 cm depth. The soil temperature data between 5 cm to 10 cm under the ground and the temperatures of the active soil surfaces are represented. The results showed that the biggest monthly sums of ground positive fluxes (G > 0) reached about 80 MJ/m2 (22.2 kWh/m2) for the bare soil from May to July and the adequate average monthly sums reached maximum 55 MJ/m2 (15.3 kWh/m2) in July. The sums for the grassy surface were nearly twice lower, with the monthly maximum equals to 42.5 MJ/m2 (11.7 kWh/m2) in June and average value of 32 MJ/m2 (8.9 kWh/m2) in July. The nine-year average annual sums for G > 0 reached 337.6 MJ/m2 (93.8 kWh/m2) for the bare soil and 170.8 MJ/m2 (59.9 kWh/m2) for the grassy surface. The heat fluxes of the 5 cm depth soil were higher than for the 8 cm and 10 cm soil. Thus, the conclusion of the study suggests that the thermal performance of SSDSL is efficient enough to be used as an environment friendly heat source for interseasonal heat pump operation.

Method for Testing and Evaluating Grassy Runway Surface

The main purpose of this study is to develop a test method to evaluate grassy airfields by determining the mechanical properties that affect airfield performance during takeoff, touchdown, and landing roll. A number of airfields with grassy or partially grassy runways in European Union countries could be more effective for flight operations with better knowledge of the surfaces and their impact on field performance. The proposed method could provide this information. The concept of the method (and an advantage over the existing methods) is to determine 1) wheel–surface braking friction, 2) rolling resistance, and 3) surface roughness. All these parameters are essential for wheel–soil interactions and performance of an airplane on the airfield. Friction coefficients would be determined with a portable tester, which has been designed and built. The complete test method will also include procedures, instructions, and comparison charts. The plan is to present the complete test method for certification so it may be used widely by the general aviation community.

Eleven years of ground–air temperature tracking over different land cover types

ABSTRACTWe have analyzed series of air, near‐surface and shallow ground temperatures under four land cover types, namely bare clayey soil, sand, short‐cut grass and asphalt; the samples were collected between 2002 and 2013 and monitored at the Geothermal Climate Change Observatory Sporilov, Prague (50°02.43′N, 14°28.54′E, 226 m a.s.l.). A comparison of all of the obtained temperature series revealed a strong dependence of the subsurface thermal regime on the respective surface cover material. The ground ‘skin’ temperature was generally warmer than the surface air temperature over all monitored surfaces; however, the temperatures over different land cover types differed significantly. Asphalt exhibited the highest temperatures, and temperatures below the grassy surface were the lowest. Special attention was paid to assessing the value of the ‘temperature offset’, the instant value of which sometimes varied dramatically, on both daily and annual scales, by up to 30+ K; however, on a long‐time scale, the temperature offset was generally constant and reflected the surface material. The characteristic 2003–2013 mean values for the individual covers are as follows: asphalt 4.1 K, sand 1.6 K, clay 1.4 K and grass 0.2 K. All four surface covers revealed typical daily and inter‐annual cycles, which were monitored and are discussed in detail. Incident solar radiation was the primary variable for determining the amount and temporal changes of the temperature offset values. A linear relationship between air–ground temperature differences and incident solar radiation was detected. The mean slope of the linear regression between both variables is clearly surface cover dependent. The greatest value, 3.3 K per 100 W m−2, was found for asphalt cover; rates of 1.0–1.2 apply to bare soil and sand cover, and a negative slope of −0.44 K per 100 W m−2 represents grass cover.

The structure of the radiation balance on a sandy surface: case the Błędów desert, Silesian Upland

Abstract Comprehensive environmental studies taking under consideration the structure of the radiation balance during the vegetation growing seasons of 2001 and 2002 were carried out on the open sandy surface of the area called the Błędów ‘desert’ located on Silesian Upland. The research in each site covered the composition of plant species, their age and height, the condition of the substratum, the composition and structure of the soil and the meteorological conditions with elements of the radiation balance. The article presents some part of the research on meteorological elements and their impact on ecosystem. Special attention was devoted to radiation conditions on the open sandy surface in the context of the formation of BSC (biological soil crust). Having presumed that the values obtained on the grassy surface constituted 100%, the values of radiation reflection measured on the open sandy surface were 185% higher and the values of net longwave radiation were 105% higher in day time and 137% in night time. Values of net radiation of about 63% lower were observed on the sandy surface during a typical sunny summer day. It was found that a strong irradiation of the sandy surface (26 MJ·m–2d–1) creates extremely difficult conditions for the initiation of the process of ecosystem formation (including BSC or plant succession). The elements of the radiation balance, net radiation, albedo and temperature of the open sandy surface were represented quantitatively. The test surfaces were classified based on the value of the albedo: group I with low albedo values, up to 0.15 (spore-bearing plants on a dark surface), including BSC; group II with mean values of the albedo from 0.16 to 0.24 (spore-bearing plants and seed on a dark grey surface); and group III with high albedo values, above 0.25 (plants growing on bare or loose sands).

Antireflective grassy surface on glass substrates with self-masked dry etching

Although recently developed bio-inspired nanostructures exhibit superior optic performance, their practical applications are limited due to cost issues. We present highly transparent glasses with grassy surface fabricated with self-masked dry etch process. Simultaneously generated nanoclusters during reactive ion etch process with simple gas mixture (i.e., CF4/O2) enables lithography-free, one-step nanostructure fabrication. The resulting grassy surfaces, composed of tapered subwavelength structures, exhibit antireflective (AR) properties in 300 to 1,800-nm wavelength ranges as well as improved hydrophilicity for antifogging. Rigorous coupled-wave analysis calculation provides design guidelines for AR surface on glass substrates.

Investigating GaSb(001) Dry Etching by ICP-RIE on a non-Silicon Containing Sample Holder with no Organic Gases

ABSTRACTWe report the dry etch of GaSb(001) by inductively coupled plasma reactive ion etcher. Silicon Oxide, deposited by PECVD, was used as a mask. The oxide layer proved to be almost unaffected compared to the GaSb, when using chlorine compound gases as etchants (Cl2, BCl3, and SiCl4) as well as argon. This provides high selectivity for GaSb to the mask layer. The sample holder has no silicon that may contribute to the etching process. Etching using Cl2 + Ar showed increase in the etching rate as the chlorine ratio increases; however, the process led to grassy surface and chemical like reaction. The use of SiCl4+Cl2+Ar mixture with low chlorine ratio resulted in anisotropic etch with smooth sides. It has been found for this case that the increase of the chlorine ratio led to an increased etching rate as well. The repeat of previously reported result by Swaminathan et al. [Thin Solid Films 516 (2008) 8712.] yet with a sample holder not having silicon, proved the effect of Si-contribution in producing vertical profile etch with smooth surfaces.

Disturbance is required for CO2-dependent promotion of woody plant growth in grasslands

The relative effects of disturbance (here defined as bare soil), competition for edaphic resources, thermal interference and elevated [CO2] on growth of tree seedlings in grasslands were studied under field conditions. Snow gum (Eucalyptus pauciflora Sieb. ex Spreng.) seedlings were grown in open-top chambers flushed with either ambient or elevated [CO2] from March 2004 to January 2005 (autumn to summer). These seedlings were planted into three treatments (i.e. bare soil, soil covered with straw or soil supporting a sward of live pasture grass) to separate effects of grass on seedling growth into those due to competition with grass for soil resources or to alteration of the thermal environment caused by a grassy surface (Ball et al. 2002). After the first major autumn frost, seedlings growing in competition with grass lost 59% of their canopy area, whereas those growing in bare soil or straw suffered negligible damage. These results reveal the complexity of competitive inhibition of plant growth in which ineffective competition for resources such as soil water enhances the vulnerability of the plant to abiotic stress, in this case frost. Tree seedlings growing in bare soil and straw commenced growth earlier in spring than those growing in competition with grass, where soil moisture was consistently lowest. Under ambient [CO2], growth was greater in bare soil than in straw, consistent with thermal interference, but these differences disappeared under elevated [CO2]. Elevated [CO2] significantly increased biomass accumulation for seedlings growing in bare soil and straw treatments, but not in grass. Thus, elevated [CO2] alleviated apparent thermal interference of seedling growth in spring but did not overcome adverse effects on seedling growth of either competitive reduction in soil resources or competitive enhancement of environmental stress. Nevertheless, elevated [CO2] could promote invasion of grasslands due to enhancement of woody plant growth in bare soil created by disturbances.

Dry etching characteristics of amorphous As2S3 film in CHF3 plasma

The authors describe the dry etching characteristics of amorphous As2S3 films in CHF3 plasma and the development of an optimized fabrication process for compact waveguides. The observed etching behavior is due to the relative densities of fluorine atoms, polymer precursors, and ions in the plasma which are controlled by the process parameters. In particular, the flow rate of the CHF3 gas has a significant influence on the etched profile and surface roughness as well as the etch rate of the As2S3. The profile evolves from isotropic to vertical with the flow rate due to passivation by increasing polymer deposition on the sidewalls. Such passivation also helps achieve smooth sidewalls because it inhibits differential etching between the phases in the inherently phase-separated As2S3 film, which otherwise results in a grainy and rough etched surface. At the highest flow rate, however, excessive polymer deposition occurs and this results in positive-sloped sidewall and grassy etched surface due to micromasking.

Polymer surface morphology control by reactive ion etching for microfluidic devices

Abstract This paper presents the novel method to control polymer surface morphology using reactive ion etching (RIE) technique and its application to microfluidic devices. By using this method, polymer surface morphology could be controlled in the wide range between smooth surface and grassy surface with a newly developed electron cyclotron resonance (ECR)-RIE system. It was found that the polymer surface morphology is closely related to metal micromask concentration on the surface. Our system could easily control the micromask concentration only by changing the total pressure in the chamber. The etching characteristics of 75 mol% O 2 –CF 4 gas mixture were systematically investigated as a function of total pressure. The smoothest surface with the arithmetic mean roughness value ( R a ) less than 10 nm was achieved at 0.1 Pa. On the other hand, the grassy surface with high aspect ratio of 80 was uniformly formed on the polymer surface under the higher-pressure range from 1.0 Pa to 1.5 Pa. Furthermore, the proposed method was applied to microfluidic channels with multiple pillars, and a hybrid structure with smooth and grassy surfaces.

Fatty acid composition of broilers from free range rearing

The study aimed to investigate the effect of rearing method on the fatty acid composition of broiler meat. The subjects were chickens of two genotypes (Ross 208 and Prelux-bro). Experiment went on for 56 days, chickens were kept in a standard deep litter house and fed the same diet. After 28 days chickens were divided into two groups of 50 birds, the first grup had a 12-hours daily access to a grassy surface (free range), the second remaining indoors. At the end of experiment, 8 broilers per group (total of 32) were randomly chosen for fatty acid composition analysis. After slaughter, breasts and legs with skin were excised, homogenised and freeze-stored. Analyses of fatty acid composition was preformed by gas-liquid chromatography (in situ transesterification). The results were processed with statistical computer program SAS. From the perspective of human nutrition, free range broilers gave meat with better fatty acid composition (increased content of w-3 and w-6 fatty acids) compared to indoor raised chickens. Fatty acid composition was more favourable for breast then leg, and for Prelux-bro than Ross 208 genotype.

Microscale temperature fluctuations in the atmospheric surface layer

Microscale temperature fluctuations were measured at 2 m above a grassy surface. The temperature-derivative spectrum was in general agreement with earlier results but the bump at nondimensional wavenumbers higher than 0.02 was not as pronounced as has been observed. The Obukhov-Corrsin constant for the one-dimensional temperature spectrum was evaluated to be 0.92 ± 0.05, consistent with recent results. The effects of instability and the vertical variation of temperature variance and kinetic energy dissipation are postulated to explain some of the difference with other spectra.

Fluctuations in the Propagation of Sound near the Ground

The fluctuation in the propagation of a pure tone over a flat grassy surface from a source on the ground has been studied over ranges of frequency (300–4000 Hz) of the source as well as height (0–5 m) and distance (15–150 m) of the receiving microphone. Preliminary analysis of the records indicates that the standard deviation of signal level about the mean initially increases nearly linearly with distance as found by previous experimenters, but for longer distances saturates at ∼6 dB as found previously only in the propagation of light. The dependence on frequency found for the unsaturated region is considerably greater than the 7/12 power predicted for large-scale isotropic turbulence, in keeping with the reduced scale expected near the ground. Signal correlation along a wavefront has also been measured. The results place limitations on the use of coherent acoustic theory for the calculation of the attenuation of noise in practice by barriers and ground interference, as well as the use of modeling techniques for solving outdoor propagation problems.

Wild Bees

A FEW words respecting a colony of wild bees (a species of Andrena) which I have just discovered in our garden, may interest your entomological readers. A day or two ago, on walking beside a low-turfed mound which supports two trees on one of our towns, I noticed that the grassy surface on the south—therefore the sunny—side was covered with little hillocks of earth, such as ants throw up after rain. On examination each little heap showed the circular hole which denotes a bee's nest, and the bees themselves were seen in many places going in and out. Some holes were level with the ground, but most had the tiny mound of soil cast up in the process of excavation. The peculiarity of the case seems to me to lie in the great number of nests forming a complete colony. It is difficult to count them, but there cannot be less than eighty or ninety in an area—roughly calculated—of about sixty square feet. Have any of your readers noticed a similar city of these busy people? and. can any one supply the specific name?