Horizontal Tiles Research Articles

Climatology and trends of wintertime diurnal temperature range over East Asia in CMIP6 models: Evaluation and attribution

Based on the 18 realizations of three state-of-the-art climate models participated in the Coupled Model Intercomparison Project phase 6 (CMIP6), this paper examines the changes in climatology and trends of winter diurnal temperature range (DTR) over East Asia in response to natural and anthropogenic forcings. In the observation, the climatology of DTR during 1979–2014 displays a horizontal tile from southwest to northeast over East Asia. In addition, the observed DTR also presents an obviously declining trend in recent decades, with the magnitude of roughly −0.10 °C decade−1. The historical all-forcing simulations well reproduce the geographical distributions and magnitude of climatology and trends of winter DTR over East Asia in 1979–2014. Furthermore, the winter DTR exhibits a continuous declining trend from the historical scenario to the future SSP245 scenario over East Asia, with the most significant declining during the first half of twenty-first century (i.e., 2021–2060). Based on the individual forcing experiments, it suggests that the greenhouse gases forcing plays a primary role in driving the climatology and trends of DTR over East Asia, especially for the SSP245 scenario. Further analysis indicates that the increasing precipitation under greenhouse gases forcing largely explain the declining DTR trends over East Asia, especially over the northern East Asia both in historical and SSP245 scenarios.

The Influence of Marina Characteristics on Non-native Colonisation

The marina properties, such as; salinity range, tidal fluctuations, depth, and ascidian presence in-fluence the distribution of invasive non-natives. Transport vectors, aquaculture and fishery practic-es also have an important role in the distribution of invasive non-native species during the bioinva-sion process. We focused on 10 invasive non-native species of marine invertebrates in the UK. This study explained the distribution and ecology of five invasive non-native species (Styela clava (As-cidia), Didemnum vexillum (Ascidia), Caprella mutica (Crustacea), Crepidula fornicata (Gastropo-da), Watersipora subtorquata (Bryozoa)) and the marina characteristics of five invasive non-native species colonization (Austrominius modestus (Arthropoda), Ciona intestinalis (Ascidia), Botrylloides violaceus (Ascidia), Tricellaria inopinata (Bryozoa), Bugula neritina (Bryozoa)) in Wales coasts. The study site deployed settlement tiles in the inner and the outer tile as two positions in each marina: An equal number of vertical and horizontal tiles was deployed at each site with half-sampled at two weeks (very early colonization) and at eight weeks (later colonization). The results showed that some variations in marina characteristics affected the distribution of invasive non-native species. Invasive non-native species abundance, diversity and multivariate structure of the assemblages were very high. The colonization of tiles varied between locations at the entrance and within the marina, but not in any way, and the effect of tile orientation was surprisingly low.

Impurity analysis of JET DiMPle pulses

Divertor monitoring pulses (DiMPle) have been run in JET from the C35 campaign onwards. They provide an opportunity to study the impurity contamination of the plasma when it is limited by different surfaces within the machine, as well as the longer term behaviour of the impurities. In these discharges the plasma is first limited on the outer wall, then on the inner wall and, subsequently, in the X-point configuration the outer strike point is positioned on the horizontal tile 5 of the machine followed by tile 6 and then the vertical tile 7. The present study details the impurity behaviour in the DiMPle pulses from JET-ILW campaigns C35 to C38, which ran from 2015 to 2019. The impurities can largely be divided into two groups. The first, including most gases, are present immediately after their use in the machine; the second group includes those elements that are retained on plasma facing surfaces within the vessel. Most of these are metals, for which a systematic behaviour is found. Influxes due to metallic dust particles behave more like the elements of the first group. The origin of the impurities where this is known is given as well as details of the systematic behaviour, including differences due to the line-of-sight of the observing spectrometer. A clear difference is seen when the discharge fuel is H and this has implications for tritium and deuterium-tritium operations.

Toroidal variation of the strike point in DIII-D

We report measurements of a+/− 5 mm toroidal variation of the outer strike point radial position using an array of three identical Langmuir probes distributed at 90° intervals around the torus (90°, 180°, 270°). The strike point radial location is determined from the profiles of floating potential (Vf) measured by the three 6 mm diameter domed Langmuir probes as the strike point is swept radially on a horizontal tile surface just outside of the upper small angle slot (SAS1) divertor. Based on the three probe measurements, the strike point variation is consistent with previous error field measurements by Schaffer [1,2] and estimates by Luxon [3] which indicated the strike point error could appear as an n = 1 radial variation of 4.5 mm at the outer mid plane and thus could be effectively described with a three point measurement. The results are also consistent with field line tracing calculations using the MAFOT code [4]. The small angle slot (SAS1) divertor performance is particularly sensitive to a misalignment with the divertor plasma since enhanced neutral confinement and recycling in the slot and distribution of neutrals along the slot surfaces are important for achieving divertor detachment at the lowest possible core plasma separatrix density. These strike point measurements are discussed with regard to the slot divertor alignment.

Quartz micro-balance results of pulse-resolved erosion/deposition in the JET-ILW divertor

A set of quartz crystal microbalances (QMB) was used at JET with full carbon wall to monitor mass erosion/deposition rates in the remote areas of the divertor. After introduction of the ITER- like wall (ILW) in JET with beryllium main wall and tungsten divertor, strong reduction of the material deposition and accompanied fuel retention was observed. Therefore the existing QMB electronics have been modified to improve the accuracy of frequency measurements by a factor of ten down to 0.1Hz which corresponds to 1.4ngcm−2. The averaged deposition rates of 1.2–3ngcm−2s−1 and erosion rates of 5.6–8.1ngcm−2s−1 were observed in the inner divertor of JET -ILW with the inner strike point positions close to the bottom edge of vertical tile 3 and at the horizontal tile 4 respectively. The erosion with averaged rates of ≈2.1ngcm−2s−1 and ≈120ngcm−2s−1 were observed in the outer divertor for the outer strike point positions at tile 5 and tile 6 respectively.

Ecological Complexity of Coral Recruitment Processes: Effects of Invertebrate Herbivores on Coral Recruitment and Growth Depends Upon Substratum Properties and Coral Species

BackgroundThe transition from planktonic planula to sessile adult corals occurs at low frequencies and post settlement mortality is extremely high. Herbivores promote settlement by reducing algal competition. This study investigates whether invertebrate herbivory might be modulated by other ecological factors such as substrata variations and coral species identity.Methodology/Principal FindingsThe experiment was conducted at the Flower Garden Banks, one of the few Atlantic reefs not experiencing considerable degradation. Tiles of differing texture and orientation were kept in bins surrounded by reef (24 m). Controls contained no herbivores while treatment bins contained urchins (Diadema antillarum) or herbivorous gastropods (Cerithium litteratum). Juvenile corals settling naturally were monitored by photography for 14 months to evaluate the effects of invertebrate herbivory and substratum properties. Herbivory reduced algae cover in urchin treatments. Two genera of brooding coral juveniles were observed, Agaricia and Porites, both of which are common but not dominant on adjacent reef. No broadcast spawning corals were observed on tiles. Overall, juveniles were more abundant in urchin treatments and on vertical, rough textured surfaces. Although more abundant, Agaricia juveniles were smaller in urchin treatments, presumably due to destructive overgrazing. Still, Agaricia growth increased with herbivory and substrata texture-orientation interactions were observed with reduced growth on rough tiles in control treatments and increased growth on vertical tiles in herbivore treatments. In contrast to Agaricia, Porites juveniles were larger on horizontal tiles, irrespective of herbivore treatment. Mortality was affected by substrata orientation with vertical surfaces increasing coral survival.Conclusions/SignificanceWe further substantiate that invertebrate herbivores play major roles in early settlement processes of corals and highlight the need for deeper understanding of ecological interactions modulating these effects. The absence of broadcast-spawning corals, even on a reef with consistently high coral cover, continues to expose the recruitment failure of these reef-building corals throughout the Caribbean.

Influence of fish grazing and sedimentation on the early post-settlement survival of the tabular coral Acropora cytherea

Processes operating in the early life stages of corals are critical in ultimately establishing patterns of adult abundance. Mortality, in particular, is assumed to be very high during the first few months to years post-settlement, but the sources of this mortality are largely unknown. This study quantified early post-settlement survival for Acropora cytherea, spawned and reared in captivity and settled onto terracotta tiles. Replicate tiles were then deployed in the field at Lizard Island, in northern section of the Great Barrier Reef to examine the effects of grazing and sedimentation on survival of corals in two different habitats, the exposed reef crest and sheltered back reef. Overall, survivorship was broadly comparable between habitats, ranging from 37.7 to 64.5 % per month on the exposed reef crest and 53.1–64.3 % on the sheltered back reef. On the reef crest, the exclusion of herbivores increased survivorship by 22.4 %, from 42.1 to 64.5 % per month. Moreover, survivorship within the reef crest was negatively correlated with the density of parrotfish feeding scars on tiles after 4 weeks. In contrast, the exclusion of herbivores had no detectable effect on survivorship within the back reef, and no feeding scars were observed on tiles in this habitat. Difference in grazing-induced mortality between habitats is most likely related to differences in herbivore size and abundance, with parrotfish biomass being 5.5-fold greater on the reef crest than the back reef. Surprisingly, tile orientation had no effect on survivorship of A. cytherea in either habitat, despite a marked difference in the sediment cover on vertical (0 %) versus horizontal tiles (30 %) in the back reef. This is in marked contrast to previous studies that have reported sedimentation is a major cause of early post-settlement mortality in corals. Clearly, processes that cause mortality of newly settled corals, such as grazing and sedimentation, vary spatially.

Erosion and deposition behaviour of a-C:H layers in the private flux region of the JET MKII-HD divertor

Material deposition was measured in the private flux region of JET by means of a quartz microbalance (QMB) for ∼11 900 s of successive plasma discharges with moderate additional heating (2–3 MW). The QMB was located under the load bearing septum replacement plate with a view towards the inner divertor. In total a ∼270 nm thick hydrogenated amorphous carbon layer was measured assuming a density of 1 g/cm 3 correlated with a fluence of 2.36 × 10 23 D + ions into a toroidal section of 1 cm length of the inner divertor. The area of the QMB in the private flux region was deposition dominated when the inner strike point position was on the vertical tiles, line-of-sight with the quartz crystal, and turned into erosion solely by moving the strike point from vertical tile 3 to horizontal tile 4. The most likely reason is a change of the C/D flux ratio of the particles impinging on QMB turning this area from a deposition to an erosion dominated region.

Sedimentation behavior of indoor airborne microparticles

Abstract Experiments on the behavior of airborne microparticle sediments and their adhesion on glass slides were conducted in a laboratory located on the first floor of a teaching building. Clean tiles and glass slides were placed at different angles (0°, 45° and 90°) with respect to the horizontal plane in the laboratory. The sedimentation of microparticles was investigated at certain time intervals (1 d, 3 d, 10 d and 30 d). The results of testing, at day 30, show that the diameters of particles on the horizontal tiles varied from 20 to 80 μm; few particles with diameter less than 0.5 μm or greater than 100 μm were found. The amount of particle sediment on all the slides increased along over time, while the average diameter of particles was not correlated with time, nor with the angle of placement. The maximum particle size, the total particle surface area, the total perimeter of all particles and the cover ratio of light (the proportion of total area of particles to the observed area of the slides surfaces) did not change significantly within the first 10 days. Inspection of all the samples for the last 20 days, however, showed that these variables increased substantially with the passage of time and were in reverse proportion to the placement angles, which indicates a concentration of particles, as well as physical and chemical changes.

Migration of 13C and deposition at ASDEX Upgrade

To investigate material transport in scrape-off layer plasma and long term deposition in divertor, 13CH4 was puffed at the end of 2004 and 2005 experimental campaigns into ASDEX Upgrade from the outer mid-plane. Ex situ analyses of the tiles were performed by secondary ion mass spectrometry. The peaks of 13C were detected below the bottom inner strike point and at the horizontal tile at the outer lower divertor. It was detected ∼21% of the total puffed 13C amount. The deposition rate for carbon by plasma was also calculated in long term experiment. It was obtained to be 22×10−3 and 8.7×10−3g/s for the upper (campaign 2004) and lower (campaign 2003) divertors, respectively.

Reappraisal of flow to tile drains I. Steady state response

Most techniques used to analyse the flow of water to horizontal tile drains fail to separate the external boundary of the water table from the internal boundary of the tile drain. This is the first of a series of three papers which consider the correct formulation of the steady state and time-variant flow to tile drains. This paper is concerned with steady state conditions and provides important information about the correct formulation of tile drainage problems, especially the fact that the drain is an internal boundary. Field experiments are quoted which demonstrate the separation of the tile drains from the water table. A finite difference numerical solution to the full differential equation is developed with the drain represented as an internal boundary. Comparisons are made between conventional methods of analysis and the numerical solution; reference is also made to layered and anisotropic soils and surcharge pressures in the drains.

338. Vacuum technology: D Santeler, Virginia Polytech Inst Eng Ext Ser Circ, 1965

A set of quartz crystal microbalances (QMB) was used at JET with full carbon wall to monitor mass erosion/deposition rates in the remote areas of the divertor. After introduction of the ITER- like wall (ILW) in JET with beryllium main wall and tungsten divertor, strong reduction of the material deposition and accompanied fuel retention was observed. Therefore the existing QMB electronics have been modified to improve the accuracy of frequency measurements by a factor of ten down to 0.1 Hz which corresponds to 1.4 ng cm−2. The averaged deposition rates of 1.2–3 ng cm−2 s−1 and erosion rates of 5.6–8.1 ng cm−2 s−1 were observed in the inner divertor of JET -ILW with the inner strike point positions close to the bottom edge of vertical tile 3 and at the horizontal tile 4 respectively. The erosion with averaged rates of ≈2.1 ng cm−2 s−1 and ≈120 ng cm−2 s−1 were observed in the outer divertor for the outer strike point positions at tile 5 and tile 6 respectively.