Intermediate Height Research Articles

A Bird's-Eye View: Novel Use of Drone Images to Quantify Differences in Altitudinal Reflections in Bird-window Collision Studies

Bird-window collisions (BWCs) constitute a significant source of mortality for both resident and migratory birds. Because windows reflect surrounding landscape components, such as vegetation or sky, birds do not always perceive glass as a barrier. Here we demonstrate a novel technique to classify and quantify reflections in windows on the Radford University campus in southwest Virginia, U.S.A. We deployed a consumer-grade Unmanned Aerial Vehicle, i.e., drone, to photograph 14 contiguous or near-contiguous window columns across five campus buildings in August 2020. For each study aspect, the drone (equipped with an RGB camera) captured images at ca. 5 m altitudinal increments from the ground floor to the roof of each building (three to six images/vertical column). We then manually classified each image in ImageJ to calculate approximate proportions of reflected: (1) vegetation, (2) sky, (3) and artificial structures or impervious surfaces, plus (4) nonreflective glass. We used a generalized linear model to determine how proportional reflections of vegetation, sky, buildings, and nonreflective glass varied across vertical increments. We found the proportion of sky significantly decreased with increasing photo heights, whereas proportion of nonreflective glass significantly increased with increasing heights. This supports previous findings that because birds are drawn to sky reflections, they may collide at relatively lower positions on buildings. Inconsistency in landscape design and building positioning on the campus precluded trends in vegetative or building reflections by height. Our pilot study demonstrates the applicability of a consumer-grade drone for investigating visual characteristics of reflections that influence BWCs from variable observation angles. We suggest the expanded use of drone images as a straightforward technique to measure changes in reflection characteristics from varying degrees of observation. They are a novel method in developing a BWC risk assessment as well as potential mitigation strategies in a suburban or campus environment with buildings of intermediate heights.

Transport Regimes of Underdamped Brownian Particles in a Tilted Washboard Potential

In this paper, a comprehensive examination of the temperature- and bias-dependent diffusion regimes of underdamped Brownian particles is presented. A temperature threshold reminiscent of a phase transition between anomalous and normal diffusive behaviors is located. In the low temperature regime, the system exhibits an apparent negative differential mobility due to persistent, long-time subdiffusion at low-bias; at high temperature (or critical bias,) the system rapidly approaches normal diffusion below an intermediate barrier height, U0 ? 6kBT. By comparison of the underdamped and overdamped response, it is demonstrated that the non-monotonic temperature dependence of the diffusivity can be traced to inertial effects. The velocity power spectra exhibit coupling between the \locked and \running states in the giant diffusion regime, with a characteristic frequency corresponding to the principal frequency of the limit cycles of a damped, driven plane pendulum near critical bias. Non-linear second harmonic generation, corresponding to oscillatory transient anomalous diffusivity, is observed with increasing bias and decreasing temperature, further emphasizing that the low-noise diffusion problem converges to noise-free dynamics, complementing analytic results for the average velocity [L. Cheng and N.K. Yip, Physica D, 2015].

Assessment and Distribution of Damages Caused by the Trunk-Boring Insects Coraebus undatus (Fabricius) (Coleoptera: Buprestidae) and Reticulitermes grassei Clément (Blattodea: Rhinotermitidae) in Mediterranean Restored Cork-Oak Forests

This work assesses damage caused by Coraebus undatus (Fabricius) (Coleoptera: Buprestidae) and Reticulitermes grassei Clément (Blattodea: Rhinotermitidae) in managed cork oak forests from the southern Iberian Peninsula. Lesions were diagnosed and quantified in relation to the following features: height and orientation in the trunk, diameter at breast height, solar exposure, understory presence and orography. The distribution patterns of lesions in the study area across 12 plots and in the trunk of the trees were also analyzed. The study was performed in “Sa de Hornachuelos” Natural Park (Córdoba, Spain) and the research area encompassed 12 environmentally-restored sampling plots. Data were recorded from 2007 to 2014, with yearly sampling from late June to mid-September, corresponding to the cork extraction period, since lesions caused by these insects are well distinguishable promptly after bark removal. The results reveal that C. undatus has low population levels and a non-uniform distribution pattern in the study area as well as in the trunk of the tree. It shows preference for medium height but not by any trunk orientation. R. grassei also shows low infestation levels and a preference to affect the trunk’s base. Comparatively, C. undatus showed higher infestation levels than R. grassei. The location of damage was also different, since galleries made by C. undatus predominated at intermediate trunk heights while those of R. grassei were more frequent at lower heights. Our results further showed a low co-occurrence of both species in the same tree trunks, which could be explained in terms of overlapping in the distribution areas of both species. These results provide background information that will enable natural resources managers to detect changes and trends of these species and inform future management decisions.

Grazing intensity drives plant diversity but does not affect forage production in a natural grassland dominated by the tussock-forming grass Andropogon lateralis Nees

Andropogon lateralis is a tall and highly plastic tussock-forming grass native from southern South America. It is a frequent component of Campos and Subtropical highland grasslands that often becomes dominant under lax grazing regimes. The aim of this work was to analyze the response of species diversity and forage production of a natural grassland dominated by A. lateralis to a wide range of grazing intensity. We hypothesized that species diversity and forage production would both peak at the intermediate canopy heights determined by grazing regimes of moderate intensity. A grazing experiment was conducted in a highland grassland with mesothermal humid climate at 922 masl (Atlantic Forest biome, Santa Catarina state, Brazil) that comprised 87 species from 20 families but had 50% of its standing biomass accounted by A. lateralis. Four pre-/post-grazing canopy heights—12/7, 20/12, 28/17, and 36/22 cm (measured on A. lateralis)—were arranged in a complete randomized block design with four replications, and intermittently stocked with beef heifers from October 2015 to October 2017. Andropogon lateralis cover decreased (from 75 to 50%), and species richness increased (15–25 species m−2) as canopy height decreased. Grazing intensity did not affect annual forage production (4.2 Mg DM ha−1). This natural grassland dominated by A. lateralis had a high capacity to adjust to grazing regimes of contrasting intensity, maintaining forage production stable over a wide range of canopy heights. However, to prevent losses in floristic diversity, such grassland should not be grazed at canopy heights higher than 28 cm.

Preliminary biometric characteristics of Greyster dogs

<b>The aim of the study was to record and analyse selected biometric data based on the results of measurements of Greyster dogs actively involved in sports. The results of our study were compared with the biometric indices of other breeds of dogs, including the original breeds from which Greysters derive, and the indices of Polish native breeds. The study showed that the Greysters were characterised by intermediate height, as compared with their original breeds, i.e. they were shorter than Greyhounds and taller than German Shorthaired Pointers, and their height index was lower than one. This means that the height at the withers dominated over the diagonal body length in the rectangular shape of the Greyster body. The massiveness index showed that the advantage of the chest girth over the height at the withers was similar to that of the Polish Greyhound. The Greyster eurysomy index was also similar to that of the Polish Greyhound. The biometric parameters of Greysters incline them to run fast. This inclination was also indicated by the leg length index and the proportions of the length of the sections of the pelvic limb. Further research is necessary to obtain full biometric characteristics of Greysters. The results obtained at this stage of the research can be used as an auxiliary tool to select these animals for reproduction or sport competitions. If a breed standard is to be established for Greyster dogs and they are classified as an FCI breed, any information with biometric data may help to set this standard.

Elite rice variety ‘VL Dhan 159’ for cultivation under organic condition of Uttarakhand hills

VL Dhan 159 is an early duration rice variety suitable for cultivation under rainfed upland organic condition of Uttarakhand hills. This variety has been developed by ICAR-Vivekananda Parvatiya Krishi Anusandhan Sansthan(VPKAS) Almora, Uttarakhand for the kharif season and released by the State Varietal Release Committee of Uttarakhand in 2020, Subsequently it was notified by the Central Seed Committee vide notification number S.O.500(E) dated the 29th January, 2021. VL Dhan 159 is derived from the cross VL 66/HPR 2143 with a maturity duration of 110-115 days. Under organic conditions, this variety has recorded an average yield of 2,054 kg/ha and out yielded the check varieties of Vivek Dhan 154 by 42.34 per cent, VL Dhan 221 by 27.34 per cent and VL Dhan 156 by 33.64 per cent. It was found resistant against leaf and neck blast (score 0-3), brown leaf spot (score 3-4), sheath rot (score 1), leaf scald (score 1-3), false smut (score 0), stem borer and leaf folder (score 0-1) under natural condition. It has more number of panicles/m2 (229) compared to the checks of Vivek Dhan 154 (200) and VL Dhan 156 (172). This variety has non lodging intermediate plant height, semi-erect with well exerted panicle. It has exhibited a better quality characteristics like high hulling (82.8%) and milling (72.1%), intermediate Alkali Spreading Value (4.0), Gel consistency (50) and amylose content (25.93%). Grain Chalkiness is very occasionally present. It has short bold grain with L/B ratio of 2.00 Key wordsVL Dhan 159, organic condition, Rainfed upland, hill rice, early duration, high yielding variety

BRRI Dhan100: A Zinc Enriched Rice Variety Suitable for Irrigated Ecosystem in Bangladesh

Recently released zinc enriched, high yielding, medium slender grain containing rice variety BRRI dhan100, appropriate for irrigated ecosystem of Bangladesh is an improvement over existing zinc enriched rice varieties for Bangladesh. The variety has satisfactorily passed the Proposed Variety Trial (PVT) conducted in the farmers’ field in Boro 2019-20 season. As a result National Seed Board (NSB) approved this variety for commercial cultivation in the Boro season (dry season) in 2021. It has modern plant type with 101 cm plant height and matures by 148 days. The proposed variety showed 1.20 t/ha higher yield than check variety BRRI dhan84. Identifying characters of this variety are green leaf, intermediate plant height, erect flag leaf, medium slender grain, intermediate leaf senescence grain. It can produce 7.7 - 8.8 t/ha grain yield. Thousand grain weight of the variety is 16.7 gm and head rice yield is 64%. The rice has zinc content 25.7 mg/kg, 26.8% amylose content with 7.8% protein content. The zinc enriched BRRI dhan100 is a superb variety for cultivating in the Boro season (dry) and farmers can be economically benefited and the country will be nutritionally benefited by the cultivation of BRRI dhan100.

Can the ground enhance vertical force for inclined stroke plane flapping wing?

The numerical investigation of 2D insect wing kinematics in an inclined stroke plane is carried out using an immersed boundary solver. The effect of vortex shedding and dipole jet on the vertical force generation by the flapping wing due to change in the stroke plane angle is investigated in the vicinity of the ground. The results of instantaneous force and vorticity contours reveal the underlying lift enhancement mechanisms for the inclined stroke plane flapping wing. Moreover, they aid in the understanding of the wake-ground interaction and the associated shear layers. The calculated average vertical force delineates different force trends for the inclined stroke plane flapping near the ground. Furthermore, the dipole jet patterns are analyzed for different heights. These patterns are found to be a better tool to assess the kinematics for the vertical force enhancement and reduction, especially at intermediate heights. Vertical force enhancement is the critical parameter in the design of the micro aerial vehicle (MAV). Through this study, it is certain that the dipole jet has the potential to be used as a lift modification mechanism in MAVs. In summary, the study gives a holistic view of the physics of the inclined plane kinematics near the ground and serves as the basis for the design of MAVs.

Anatomic Description of the Distal and Intercuneiform Articulations: A Cadaveric Study

The medial, intermediate, and lateral cuneiforms play a pivotal role in foot biomechanics. When correcting deformities of this joint complex understanding the clinical anatomy remains imperative to provide both anatomic reduction and appropriately sized fixation. This study qualitatively and quantitatively describes the distal and intercuneiform articulations and their clinical implications. The cuneiform complex of 10 fresh-frozen cadavers was dissected, and the width of the complex was measured with digital calipers. Following further dissection, the distal articular surface shapes of each cuneiform were described, and the individual heights and widths were measured. The intercuneiform articular facets were described and the protrusion distances, between the medial and lateral cuneiforms with the intermediate cuneiform, were measured. The width of the joint complex was 44.74 ± 3.40 mm. The medial cuneiform height, width, dorsal anterior, and plantar protrusion distances were 32.58 ± 2.77 mm, 14.08 ± 2.26 mm, 8.51 ± 2.17 mm, and 6.66 ± 1.21 mm, respectively. The intermediate cuneiform height and width was 23.05 ± 1.92 mm and 9.59 ± 1.85 mm, respectively. The lateral cuneiform height, width, dorsal, and plantar anterior protrusion distances were 23.38 ± 2.67 mm, 10.98 ± 3.01 mm, and 6.76 ± 1.43 mm, and 4.19 ± 1.10 mm respectively. The anterior surface of the medial, intermediate, and lateral cuneiforms was described as reniform, triangular, and triangular, respectively. The majority of intermediate cuneiforms shared an inverted L-shaped articulation with the medial cuneiform, and a B-shaped articulation with the lateral cuneiform. The shapes and sizes of distal and intercuneiform articulations were described with shared anatomical features across cadavers. Understanding the dimensions of the respective surfaces allows for anatomically appropriate fixation size.

Identification of generic drilling task phases and height effect: Coupling of kinematic and kinetic data

BackgroundThe prevention of work-related musculoskeletal disorders (MSDs) is an important issue for the health of operators, especially when the workload is heavy, such as in drilling activities. Research questionThis study aimed to propose an objective identification and description of the different phases that comprise a drilling task as well as a biomechanical and ergonomic evaluation of the subjects' overall posture during its effective part. MethodsFourteen healthy subjects performed three successive drillings at two different heights, 130 (H130) and 170 cm (H170) from the ground, of a 3 mm thick steel plate. Kinematic and kinetic data were simultaneously acquired using a Qualisys motion capture system and a force platform. The speed profiles of each body segments and the evolution of the force exerted were analysed to identify the different phases. Then, the average joint angles of the whole body were calculated during the drilling phase for the two heights considered and compared. Finally, the measured postures were qualified through the Rapid Upper Limb Assessment (RULA) score in order to assess the risk of developing MSDs for each condition. ResultsThe drilling task could be divided into five phases whatever the condition: transport, aiming, repositioning, drilling, and return. The increase in height has doubled the duration of the drilling phase while reducing the force exerted by about 30 %. Similarly, height variation significantly influenced the subjects' posture, mainly in the head, trunk and upper limbs, and the RULA scores obtained for conditions H130 and H170 were 6 and 7 respectively. SignificanceThe results indicate, on the one hand, the relevance of coupling kinematic and kinetic data in order to analyse the drilling task and, on the other hand, that operators are exposed to considerable risk of developing MSDs, even at intermediate heights, which increase as the height increases.

Registration of ‘Resilience CL+’ soft white winter wheat

Abstract‘Resilience CL+’ (Reg. no. CV‐1176, PI 686413; PVP 201800104) is a soft white common winter wheat (Triticum aestivum L.) cultivar carrying two‐gene tolerance to imazamox herbicide that was developed and released in October 2016 by the Agricultural Research Center of Washington State University. It was tested under the experimental designations KCF9002 and WA 8187. Resilience CL+ was developed using marker‐assisted background selection and marker‐assisted forward breeding approaches involving a cross between a soft white winter wheat cultivar ‘Madsen’ and CL0618 (an Australian hard red spring two‐gene Clearfield line). Resilience CL+ carries two mutation alleles (Als1 and Als2) of the acetolactate synthase gene (ALS) located on chromosomes 6DL and 6BL. Resilience CL+ has high grain‐yield potential, intermediate plant height, and is well adapted to regions of the inland Pacific Northwest (PNW) with >500 mm of annual precipitation. Resilience CL+ exhibited herbicide tolerance equivalent to ‘AP503 CL2’ and greater than the single‐gene Clearfield cultivar ‘ORCF‐102’. Compared with the other Clearfield cultivars grown in the PNW, Resilience CL+ has a high level of resistance to stripe rust and foot rot resistance, similar to that of Madsen. Resilience CL+ has soft kernels, an excellent milling score, and good end‐use quality characteristics. Yield comparison of Resilience CL+ with other popular cultivars demonstrated that it has greater yield than ‘SY Ovation’ and Madsen but is similar to ORCF‐102.

The influence of range hood mounting height on capture efficiency

A new test procedure for determining capture efficiency (CE) of domestic range hoods (ASTM-E3087.18) was used to investigate how the range hood mounting height above a stove influences CE. Previous studies on CE utilized only two heights for a single range hood and a test procedure that did not strictly adhere to ASTM-E3087.18. In the study reported herein, testing was performed in accordance with ASTM-E3087.18 on six range hoods of similar design at three heights. The measured CE values ranged from 42.8–96.2%CE with CE changing by 8.2%CE at worst when varying the height for a specific fan. The influence of mounting height on CE uncertainty, repeatability, reproducibility and variability were also investigated. Lower mounting heights were found to increase CE and reduce uncertainty at the cost of increased variability between repeat tests. In contrast, intermediate mounting heights typically improved variability performance and repeatability/reproducibility. One range hood with vents for re-circulation showed higher uncertainty and more variability, indicating that flow exhausting from these vents can influence CE performance. Thus, it is possible that future ASHRAE/HVI certification standards be written with re-circulating vents sealed off during testing and a specified mounting height to minimize variations in CE caused by varying mounting heights.

New drought-tolerant rainfed upland rice (Oryza sp.) genotypes adapted to the west, centre-west, and centre regions of Côte d'Ivoire

To select new rainfed upland rice genotypes, adapted to the West, Centre-West, and Centre regions of Côte d'Ivoire, a study was conducted in research stations. Six genotypes (ART15-11-8-5-2-B-1, WAB891-SG12, WAB1092-B-40AB.1, ARCC3Fa3L10P1-1-B-1, and ART15-16-12 -3-1-B-1-B-3-1) including the control IDSA 10, widely cultivated across the country, were evaluated on three research stations of the National Center of Agricultural Research (CNRA), during the wet seasons of the year 2016 and 2017. These stations are located at the West, Center, and West-Center of Côte d'Ivoire. The trial was set up in a randomised complete block design with four replications. The agromorphological traits such as tillering ability, sowing-50% heading cycle, plant height, percentage of productive tillers, sowing-maturity cycle, and paddy yield were collected for each genotype. In all the environments evaluated, the genotypes ART15-11-8-5-2-B-1, WAB891-SG12, ARCC3Fa3L10P1-1-B-1, and ART15-16-12-3-1-B-1-B -3-1 were characterised by high percentages of productive tillers (87 to 91%), intermediate plant heights (114 to 121 cm), and high average paddy yields (2,601 to 2,810 kg/ha). Yield gains of these genotypes compared to the control ranged from 16 to 25%. The Genotype × Environment interaction (G × E) was highly significant for paddy yield (p < 0.001). The study of the interaction based on the first two principal components analysis of the GGE biplot, explained a 97% of the main effect of the Genotype and the G × E interaction. The polygon tool of the biplot suggested the existence of a single complex mega-environment. Visualizing the mean and stability of genotypes' paddy yield in the biplot indicated that genotypes ART15-11-8-5-2-B-1, WAB891-SG12, ARCC3Fa3L10P1-1-B-1, and ART15-16-12-3-1-B-1-B- 3-1 were more adapted to upland rice-growing regions of the West, Center-West, and Center of Côte d'Ivoire. These genotypes can be released for large scale rice production in these regions. Keywords: Rainfed upland rice, G × E interaction, GGE biplot analysis

Evaluation Criteria and Benefit Analysis of Mixing Process in Anaerobic Digesters of Biogas Plants

Abstract A valid method to evaluate decisions of a project proposal is the so-called cost-benefit analysis. Criteria are selected and properly weighted to determine if the project is effective and feasible. The present research study is focused on methodical selection of design parameters to install two propeller mixers inside anaerobic digesters of biogas plants. A cylindrical tank of 1400 m3 was considered. For the model-based optimisation, the substrate was considered as a non-Newtonian fluid with a density of 1090 kg/m3. The Oswald-de Waele power-law model was selected to account for the rheological behaviour of the fluid. Installation parameters of the mixers were rotational angles and heights of the shafts of the two propellers. A computational model was developed to simulate the fluid dynamics depending on the mixing process inside the tank. Several configurations were analysed according to evaluating criteria such as the value of the fluid velocity, its distribution along the three spatial dimensions, and the power consumption to rotate the mixers. The maximum fluid velocity and minimum power consumption were observed when the propellers are located at intermediate height inside the tank and with the shafts perpendicular to the tank radius. With this configuration, the fluid reaches a maximum velocity of 0.28 m/s. According to the investigation, it is evident that mixing systems with propeller shafts deep-seated and parallel to the tank radius should be avoided, both in term of efficiency of the fluid mixing distribution and in term of power consumption.

Fruit provision from Berberis microphylla shrubs as ecosystem service in Nothofagus forest of Tierra del Fuego

Berry production is a non-wood product worldwide recognized by its nutritional value and taste, but the most studied species are non-native commercial plants in productive areas, leaving aside native berries. We propose that native berries (Berberis microphylla G.Forst) naturally growing in degradation forests areas could diversify livestock establishment production and complement traditional uses (e.g., livestock). The aims of this work were to 1) environmentally characterize (e.g., soil nutrient content and physical conditions, air conditions and photosynthetically active radiation) in three degraded Nothofagus antarctica Oerst. forest (due to past fires and livestock use) of Tierra del Fuego; and 2) evaluate berries production of B. microphylla in terms of quality production (e.g., fruit number and weigh per shrub) and in terms of quality (individual fruit weight, fruit pulp percentage, and soluble solids content) to assess provisioning ecosystem service of this native shrub in different degraded areas. Studied sites were defined as: 1) Severe soil degradation condition (SEV) (high frequency of horses, bulls and some native guanacos year round, severe soil erosion, and shorter herbaceous layer), 2) Moderate soil degradation condition (MOD) (cattle and guanaco year round, intermediate level of soil erosion and intermediate height of herbaceous layer), and 3) Slight soil degradation condition (SLI) (livestock only during winter, but high frequency of native guanacos, lower soil erosion and taller herbaceous layer). (SEV) had the highest air and soil temperature, least soils nutrients content, highest bulk density, the least soil water content and the poorest fruit production. (MOD) had the highest soil water content and nutrient-rich soils, while (SLI) had the highest relative air humidity and PAR. B. microphylla shrubs grow with similar morphology on the different soil degraded condition. The highest fruit production were at (SLI), however the (SEV) had the highest soluble solids. We conclude that calafate shrubs in degraded Nothofagus forests offer a provisioning ecosystem service through their excellent fruits quality. Livestock farms could diversify their production through native fruits taking advantage of the altered areas occupied by B. microphylla. However, we recommend avoiding intensive livestock use in burned forests since it could lead to an irreversible soil erosion. Proper livestock management in Nothofagus burned forest could keep over the time not only the recognized ecosystem provision services (fruits, meat, wood), but also those of regulation and support that calafate shrubs offer and that make the functionality of the ecosystem.

Registration of ‘Curiosity CL+’ soft white winter wheat

Abstract‘Curiosity CL+’ (Reg. no. CV‐1167, PI 675007; PVP 201500290) is a soft white winter (SWW) wheat (Triticum aestivum L.) cultivar carrying two‐gene tolerance to imazamox herbicide that was developed and released by the Agricultural Research Center of Washington State University in October 2013. It was tested under the experimental designations EBC2F3‐3‐18 and WA008143. Curiosity CL+ was developed using marker‐assisted background selection involving a cross between ‘Eltan’ and ‘CL0618’. Eltan was a predominant SWW wheat cultivar (released in 1990) in the Pacific Northwest (PNW), whereas CL0618 is an Australian hard red spring line carrying two‐gene mutations conferring herbicide tolerance. Curiosity CL+ carries two mutation alleles (AhasL‐B1 and AhasL‐D1) of acetolactate synthase gene copies on chromosomes 6B and 6D. Curiosity CL+ has high grain‐yield potential, intermediate plant height, and is well adapted to the dryland production areas of the PNW with <300 mm of annual precipitation. Tested in multiple location and years, Curiosity CL+ showed herbicide tolerance equivalent to the two‐gene Clearfield cultivar ‘AP503 CL2’ (PVP 200800322) and higher than the single‐gene Clearfield cultivar ‘ORCF‐102’ (PI 641787). Its end‐use quality is similar to ORCF‐102, ‘Stephens’ (CI 17596), and ‘Xerpha’ (PI 645605). Compared with Eltan, Curiosity CL+ has better stripe rust resistance, whereas the level of snow mold and Cephalosporium stripe tolerance is equal.

Interfacial flow dynamic micro-response and spatiotemporal evolution of flow pattern for thermocapillary–buoyancy convection in a liquid bridge

Compared with the former studies, the perturbation behavior of thermocapillary–buoyancy convection caused by the simultaneous coupling response of the microscale surface flow, free surface deformation and spatiotemporal evolution of flow patterns is revealed by the combination of experimental and numerical methods for the first time. The free surface morphology transforms from the ‘Ƨ’-shape into the twisted ‘M’-shape in the corresponding balanced stage of thermocapillary–buoyancy convection (at t = 975, Bod = 251.5), and eventually becomes ‘Ƨ’-shape in the corresponding third stage (Bod = 229.9). Meanwhile, there is a weak response of the free surface flow during each transition stage accompanied by periodic hydrothermal waves. The perturbation characteristics of the velocity, the temperature and the transverse location of surface flow are the most prominent at the intermediate height of liquid bridge (y = 0.2). The characteristic of longitudinal velocity mainly presents as the pulsation, while there is also the pulsation inside the oscillation of transverse velocity with the large amplitude (the oscillating period of 2fu = 7.2 s and the amplitude of Au = 0.0057). The periodic characteristic of temperature oscillation is obvious (2fθ = 0.2 s, Au = 0.015).

Numerical and experimental study of the heat transfer process in a double pipe heat exchanger with inner corrugated tubes

In this study, 3-D numerical simulations were carried out to analyse the influence of geometrical parameters for eight spirally inner corrugated tubes at turbulent flow (Re=25×103) in a double pipe heat exchanger. As a novelty, different combinations of pitch and height in a 3-D inward corrugated tube numerical model were analysed and validated with an experimental setup. This had not previously been conducted in a double pipe heat exchanger. Furthermore, the numerical model included the entire geometry of the heat exchanger, with dimensions of the computational domain similar to those used in actual commercial applications. Grid independence analysis of the numerical solution was performed based on a 3-D unstructured tetrahedral mesh scheme, considering the Realizable k−ε turbulence model. Case 8, with the highest corrugation height (H/D=0.05) and the lowest helical pitch (P/D=0.682) presented the highest pressure drops in both inner and annular tubes, being 4.15 and 1.27 times higher in the inner tube and in the annulus side than in the smooth tube, respectively. Regarding heat transfer, Case 9, with the smallest helical pitch and an intermediate corrugation height (H/D=0.041) obtained the highest number of transfer units (NTU) value, which, under the experimental conditions of this work, resulted in an increase of 29% compared with the smooth tube. In Cases 7 and 9, the inner tubes showed optimal results when considering the combined influence of the enhanced heat transfer performance and pressure drop using the performance evaluation criteria (PEC).

Horizontal distribution affects the vertical distribution of native and invasive container-inhabiting Aedes mosquitoes within an urban landscape.

The vertical dimension constitutes an important niche axis along which mosquitoes may adjust their distribution. Here, we evaluated whether the vertical distribution of container-inhabiting Aedes mosquitoes differs along a gradient of anthropogenic land-use intensity within an urban landscape. Using a pulley system, we hung oviposition cups at three heights (ground level, 4.5, and 9 m) and in three habitats: forest, park, and a built environment. We hypothesized that mosquito abundance and diversity would be highest in the least disturbed forest habitat, decrease in the park, and be lowest at the UNC-Greensboro campus. We also expected Aedes albopictus (Skuse) and Ae. triseriatus (Say) to mainly oviposit at ground level and Ae. hendersoni (Cockerell) at canopy height. Aedes albopictus was the most common species (68.8%) collected in all three habitat types and was the only species found in the built environment. In that habitat, Ae. albopictus exhibited a bimodal distribution with the lowest activity at the intermediate height (4.5 m). Aedes triseriatus (28.9%) did not differ in egg abundance between the forest and park habitats but did exhibit diverse vertical habitat use while avoiding the canopy in the park habitat. Aedes hendersoni (2.3%) was the most sylvatic species and oviposited only at ground level. Our results indicate that the vertical distribution of mosquitoes is affected by the type of habitat in which they occur, and that this variation could be driven via local-scale modification of microclimatic factors.

A robust second-order surface reconstruction for shallow water flows with a discontinuous topography and a Manning friction

A second-order surface reconstruction (SR) method for the shallow water equations with a discontinuous bottom topography and a Manning friction source term is presented. We redefine the water surface level at the cell interface by using the minimum difference between the bottom level and the original water surface level. The reconstructed water surface level is used to define the intermediate bottom level and the intermediate water height at the cell interface. We propose an explicit-implicit method to address the friction source term. The new second-order SR scheme together with the explicit-implicit method can preserve a special steady-state solution of the system and can maintain the positivity of the water depth. We also extend the new scheme to two-dimensional shallow water flows. To demonstrate the robustness and effectiveness of the new scheme, we use several classical numerical experiments for the shallow water flows over a complex bottom topography.