Miracle-dz/UniFAR-FTUs huggingface dataset:
Deformation and melting of steel projectiles in hypervelocity cratering experiments

Abstract– We carried out hypervelocity cratering experiments with steel projectiles and sandstone targets to investigate the structural and mineralogical changes that occur upon impact in the projectile and target. The masses of coherent projectile relics that were recovered in different experiments ranged between 58% and 92% of their initial projectile masses. A significant trend between impact energy, the presence of water in the target, and the mass of projectile relics could not be found. However, projectile fragmentation seems to be enhanced if the target contains substantial amounts of water. Two experiments that were performed with 1 cm sized steel projectiles impacting at 3400 and 5300 m s−1 vertically onto dry Seeberger sandstone were investigated in detail. The recovered projectiles are intensely plastically deformed. Deformation mechanisms include dislocation glide and dislocation creep. The latter led to the formation of subgrains and micrometer‐sized dynamically recrystallized grains. In case of the 5300 m s−1 impact experiment, this deformation is followed by grain annealing. In addition, brittle fracturing and friction‐controlled melting at the surface along with melting and boiling of iron and silica were observed in both experiments. We estimated that heating and melting of the projectile impacting at 5300 m s−1 consumed 4.4% of the total impact energy and was converted into thermal energy and heat of fusion. Beside the formation of centimeter‐sized projectile relics, projectile matter is distributed in the ejecta as spherules, unmelted fragments, and intermingled iron‐silica aggregates.
Narrow grass hedge effects on runoff and soil loss.

Abstract: This rainfall simulation study provided information on the effects of 0.72 m (2.4 ft) wide switchgrass hedges located at the bottom of plots on runoff and soil loss under both no-till and tilled conditions. The study area, which had slopes ranging from 8 to 16%, had produced corn for 33 years and the grass hedges had been established for six years. Simulated rainfall [64 mm hr−1 (2.5 in hr-1)I was applied for two hours to plots (3.7 m (12 ft) wide by 10.7 m (35.1 ft) long/with corn residue and to plots where corn residue was removed. The narrow grass hedges substantially reduced runoff and soil loss. Under no-till conditions, the plots with corn residue and pass hedges averaged 52% less runoff and 53% less soil loss tban similar plots without grass hakes. Under tilled conditions, the plots with corn residue and grass hedges averaged 22% less runoff and 57% Less soil loss than comparable plots without grass hedges. The plots with corn residue removed but with grass hedges present averaged 41 % less runoff and 63% less soil loss than similar plots without grass hedges. Narrow grass hedges are an effective conservation measure, especially when used in conjunction with such conservation practices as no-till or reduced-till firming systems.
Nanofluids: Thermophysical Analysis and Heat Transfer Performance

Nanofluids can be described as colloidal suspensions of solid particles smaller than 100 nm diluted in a base fluid. According to the literature nanofluids have better thermophysical properties and might achieve better cooling performance compared to conventional liquids. The current Master Thesis is divided into two main sections; the first part consists of the analysis of thermal conductivity and viscosity of nanofluids, while the second part is about the performance of forced convective heat transfer in laminar flow with nanofluids. For the evaluation of thermal conductivity and viscosity, which are the main two important thermo-physical properties, different nanoparticles were tested, such as Al2O3 (with 3-50 w%), TiO2 (with 3-40 w%), SiO2 (with 3-45 w%) and CeO2 (with 3-20 w%); all of them dispersed in distilled water. The results have been compared with the results provided by the Chemical Department of University of Birmingham for validation/comparison. Moreover, temperature effect on viscosity and thermal conductivity has been studied as well. Furthermore, some theoretical models have been used in order to understand the behavior of thermal conductivity and viscosity. For the second part, several nanofluids have been tested to evaluate heat transfer coefficient in a horizontal open micro-tube test section under laminar flow regime. The test section had an inner diameter of 0.50 mm and 30 cm length made of stainless steel. Along the pipe, seven thermocouples were unevenly attached on the outer surface in order to measure the local wall temperatures. Furthermore, two more thermocouples were used to measure inlet and outlet temperatures. A differential pressure transducer was used to measure pressure drop, and a DC power supply was used to apply constant heat flux along the test section; moreover, a double syringe pump were used to inject nanofluids inside the microtube.
Total albedo of Great Lakes ice

The total (0.3-3.0μ) albedo of various types of ice common to the Great Lakes ranged from 10% for clear ice to 46% for snow ice at solar altitudes ranging from 32 to 40 degrees. Explanations are given for similarities between the albedo of pancake (31%) and slush curd ice (32%), and slush (41%) and brash ice (41%).
Tests of the rigid-plate hypothesis and bounds on intraplate deformation using geodetic data from very long baseline interferometry

The geodetic results of Ma et al. [1994] from very long baseline interferometry are used to assess rates of intraplate deformation. We analyze the resulting set of velocities of 18 plate-interior sites, nine on the North American plate, four western European sites on the Eurasian plate, three on the Pacific plate, and two on the Australian plate. We formulate three alternative error budgets based partly on the work of Ryan et al. [1993a]: an optimistic error budget, a conservative error budget, and an upper bound error budget. All three budgets assume the existence of a previously unmodeled error that is inversely proportional to the time span of observations at a site. Use of the conservative error budget indicates no significant motion between sites on any one of the four plates. Use of the upper bound error budget, designed to be precisely large enough to be consistent with rigid plates, places a usefully small upper bound on how fast any site might be moving relative to the rest of its plate. Speeds faster than 2 mm/yr are excluded at the 95% confidence level for seven of the 18 plate-interior sites. Adjustments of the site velocities for motion due to postglacial rebound as predicted from the model of Tushingham and Peltier [1991] give an insignificant improvement to the fit of the horizontal velocities to the rigid plate model. The velocities of six sites near the western margin of the interior of the North American plate were also analyzed. Use of the conservative error budget indicates that a site near Fairbanks (Alaska) has an upper bound of 3 mm/yr on its speed, a site in Nome (Alaska) has an upper bound on its speed of ∼8 mm/yr, and a site in Penticton (British Columbia) has an upper bound on its speed of ∼4 mm/yr. Of three sites on the Colorado Plateau, two move marginally significantly, and one moves insignificantly relative to stable North America. Upper limits on their speeds relative to stable North America range from 4 to ∼5 mm/yr. We conclude that the data do not yet demonstrate significant velocities between sites in the stable interior of any one plate but do provide useful and small upper bounds of 2 mm/yr or less on the speeds of the best observed intraplate sites. Six sites near the western margin of the North American interior have upper bound speeds of 3 to 8 mm/yr.
The Heated Condensation Framework. Part II: Climatological Behavior of Convective Initiation and Land–Atmosphere Coupling over the Conterminous United States

AbstractThis is Part II of a two-part study introducing the heated condensation framework (HCF), which quantifies the potential convective state of the atmosphere in terms of land–atmosphere interactions. Part I introduced the full suite of HCF variables and applied them to case studies with observations and models over a single location in the southern Great Plains. It was shown in Part I that the HCF was capable of identifying locally initiated convection and quantifying energetically favorable pathways for initiation. Here, the HCF is applied to the entire conterminous United States and the climatology of convective initiation (CI) in relation to local land–atmosphere coupling (LoCo) is explored for 34 summers (June–August) using the North American Regional Reanalysis (NARR) and observations. NARR is found to be capable of capturing the convective threshold (buoyant mixing potential temperature θBM) and energy advantage transition (energy advantage potential temperature θadv) for most of the United Sta.
An Attempt to Explain the Distribution of the Tree Species Composing the Riparian Forests of Lake Duparquet, Southern Boreal Region of Quebec, Canada

The objective of this study was to evaluate the most important environmental factors determining the distribution of tree species within the riparian zone of Lake Duparquet, located in the southern boreal region of Quebec, Canada. Occurrence and relative basal area of 10 species were recorded within an altitudinal range of 200 cm above mean water level along 95 transects. Stepwise logistic regression and canonical correspondence analyses were performed on the overall data set as well as separately for the five geomorphological shore types distinguished (depositional flats, floodplains, beaches, terraces, and rock outcrops). The elevation gradient, representing seasonal floodings, is the main factor determining the distribution of the species. The differences between the geomorphological shore types with respect to composition and arrangement of the arborescent vegetation along the elevation gradient are at least partially explained by surficial substratum, topography, aspect, and fire. Exposure to wave ac.
Temporal and alongshore distribution of decapod larvae in the oceanic island of Gran Canaria (NW Africa)

Larval transport strongly influences neritic populations of oceanic islands. We investigated the spatial-temporal variability of the assemblage of decapod larvae at the shelf edge off Gran Canaria Island. Environmental and planktonic monitoring were conducted weekly from January to July 2001, at three stations located at different positions in relation to the Trade winds and Canary Current. A total of 5969 decapod larvae of 112 different taxa were recorded. Temporal distribution of decapod larvae abundance displayed two main peaks: the first one took place during February–March associated with the mesozooplankton increase and the second in June–July related to a rise in temperature. The spatial distribution of larvae had a windward–leeward pattern. Larval abundances were much higher in the area of the weak flow around the stagnation point upstream of the island and the warm lee region downstream and were dominated by the benthic species: Galathea intermedia, Philocheras bispinosus, Anapagurus spp. , Nanocassiope melanodactyla and Xantho spp. In contrast, on the flank of the island where the current and winds increase, abundances decreased notably with a higher contribution of holopelagic species, such as Gennadas spp. and Deosergestes henseni, suggesting a greater influence of the open ocean waters. Oceanographic conditions related to the island mass effect seems to control the retention zones for decapod larvae. The stagnation point and the lee of the island clearly favour the maintenance of the larval pool nearshore and the self-recruitment in the neritic populations. Consequently, these
Thrust and extensional faulting under the Chilean coast: 1965,1971 Aconcagua earthquakes

Summary. Earthquakes under coastal northern Chile, from 18° S to 33° S occur at two very different depths. The shallower interplate events have the typical thrust mechanisms associated with subduction of the Nazca Plate under South America. The deeper (close to 70 km) events have normal fault mechanisms with a tension axis approximately parallel to the dip of the downgoing slab. We study in detail a. couple of Ms∼ 7.5 events that took place about 60 km north of Valparaiso, Chile. The 1971 July 9 event was a shallow thrust interplate event at 40 km depth, while the 1965 March 28 earthquake had a normal fault mechanism and a depth of 72 km. We carry out a detailed analysis of long period P-and surface waves observed in the WWSSN network of stations in order to improve fault plane solutions and depth determinations. For the 1971 event we find a seismic moment of 5.6 ∼ 1027 dyne cm from both P-and surface waves. The source area for this event is relatively small compared to that of other underthrust events with similar moments. Assuming a circular fault shape and a rigidity of 7 ∼ 1011 dyne cm−2 we find a stress drop of 38 bar. The 1965 event is more complex; seismic moments of 1.8 and 1.0 ∼ 1027 dyne cm are found from surface and body waves respectively. The stress drop estimated from P-waves and a circular fault model is close to 91 bar. The existence of earthquakes at two different depths near the Chilean coast may be interpreted in terms of a double layered Benioff zone, as has been found in Honshu, Kuriles or central Peru. Unfortunately the hypo-central determinations of events in this region are not precise enough to separate the two layers. An alternative method to demonstrate the existence of a double Benioff zone is to look for compressional events associated with the upper layer of the down-going slab. A search among available fault plane solutions is ambiguous; three shallow coastal events are found in Stauder's catalogue with horizontal pressure axes normal to the trench, but they might be intra-continental plate events.
Intercomparison of surface energy flux measurement systems used during the HiWATER‐MUSOEXE

Agreement among instruments is very important for the Multi‐Scale Observation Experiment on Evapotranspiration over heterogeneous land surfaces of The Heihe Watershed Allied Telemetry Experimental Research (HiWATER‐MUSOEXE), particularly in regard to radiation and turbulent flux measurements. Before HiWATER‐MUSOEXE was conducted, 20 eddy covariance (EC) system sets, 18 radiometer sets, and seven large aperture scintillometers (LASs) sets were intercompared over the Gobi desert between 14 and 24 May 2012. For radiometers, the four‐component radiation measurements exhibited good agreement—the average root‐mean‐square error (RMSE) and mean relative error (MRE) for the net radiation were 10.38 W m−2 and 1.24%, respectively. With regard to the EC systems, the best consistency for sensible heat fluxes was found among CSAT3 sonic anemometers and Li7500A/Li7500/EC150 combinations (average RMSE, 12.30 W m−2 and MRE, −1.36%), followed by Gill sonic anemometers and Li7500A/Li7500 combinations when a proper angle of attack correction method was applied (average RMSE, 16.75 W m−2 and MRE, −5.52%). The sensible heat flux measured using different LASs agreed well with high correlation coefficients—the average RMSE and MRE values were 10.26 W m−2 and 5.48% for boundary layer scintillometer (BLS) 900, 16.32 W m−2 and 10.47% for BLS450, and 14.38 W m−2 and −3.72% for ZZLAS, respectively. The EC and LAS measurements were compared and agreed well over homogeneous underlying surfaces, which also indicated that the EC and LAS measurements would be comparable in the follow‐up experiment. The intercomparison results can be used to determine instrument placement and are very helpful for subsequent data analysis.
From Rifted Margins to Foreland Basins: Investigating Provenance and Sediment Dispersal Across Desert Arabia (Oman, U.A.E.)

Arid Arabia, where chemical weathering and anthropic modifications are negligible, is a huge natural laboratory for the study of sediment provenance. Mafic and ultramafic detritus from ophiolite belts is found along the Oman Mountains and on Masirah Island ("obduction-orogen provenance"). Dominant cellular serpentinite grains from residual mantle harzburgites of the Sama'il ophiolite contrast with gabbroic, diabase, and basaltic grains from igneous crustal rocks of the Masirah ophiolite. Detritus from autochthonous basement and cover rocks is found along the Arabian Sea margin ("rift-shoulder provenance"). Transition from carbonate-dominated lithic sands ("undissected stage") to hornblende-rich plagioclase arkoses ("dissected stage") is best documented at the northern edge of the Gulf of Aden. Along the older, strike-slip Owen-basin margin, only locally are feldspars, hornblende, and garnet derived from small outcrops of Pan-African basement. Modern eolian sands from Yemen to the Arabian (Persian) Gulf display marked enrichment in quartz, low plagioclase/feldspar ratios, and depleted dense-mineral assemblages with rounded epidotes, hornblende, garnet, and ultrastables, pointing to extensive recycling also fostered by Quaternary changes. The Rub'-Al-Khali and Wahibah sand seas have distinct quartz/feldspar ratios, reflecting largely separate transport pathways. Dune fields, fed chiefly from rift highlands in the west and south, mix with orogenic detritus in the northeast. Carbonate-dominated sands in coastal UAE are mostly derived from the Zagros Mountains, blown by northerly Shamal winds across the Gulf during Pleistocene lowstands to reach the backbulge depozone and the foreland beyond. Contributions from the Oman Mountains reach only 5-10% of bulk sediment along their southern apron, and mostly indirectly through deflation of Plio-Pleistocene fans. The Sama'il ophiolite supplies enstatite and diopside to the eastern UAE and Wahibah sands; the Masirah ophiolite supplies amphiboles and clinopyroxenes locally along the Batain coast. The composition of desert sediments faithfully mirrors tectonic history of source terranes, deformation style during orogeny, and unroofing level during extension. Bulk petrography coupled with dense-mineral analysis thus represents a powerful tool to investigate not only provenance and sediment transport but also crustal dynamics and geologic evolution at continental scale.
Millennial- to Centennial-Scale Interruptions of the Oceanic Anoxic Event 1b (Early Albian, mid-Cretaceous) Inferred from Benthic Foraminiferal Repopulation Events

Abstract The Early Albian Oceanic Anoxic Event 1b (OAE 1b) black shale is interrupted by one or more ventilation events that display significant changes in benthic and planktic populations. Within the OAE 1b sections studied, at ODP Site 1049, DSDP Site 545, and the Vocontian Basin, the benthic foraminiferal repopulation events last between ∼500 and ∼1,250 years and occur with a cyclicity of approximately 5.7 kyr. This period may represent an amplitude modulation of the precessional cycle. The OAE 1b sections from the marginal setting of the Vocontian Basin exhibit up to eight repopulation events. In contrast, there is only one repopulation event identified in the Atlantic OAE 1b sections from the Mazagan Plateau (DSDP 545) and Blake Nose (ODP 1049). Within the margin of dating uncertainties, this supraregional repopulation event occurred synchronously in the Vocontian Basin and the Atlantic Ocean. While the OAE 1b black shale formed under extremely warm and humid conditions, the repopulation events occurred during intervals of short-term cooling and reduced humidity at deep-water formation sites. The resulting increase in evaporation led to enhanced formation of low-latitude deep water, thus improving the ventilation of the sea floor.
Arctic sea ice in transformation: A review of recent observed changes and impacts on biology and human activity

Sea ice in the Arctic is one of the most rapidly changing components of the global climate system. Over the past few decades, summer areal extent has declined over 30%, and all months show statistically significant declining trends. New satellite missions and techniques have greatly expanded information on sea ice thickness, but many uncertainties remain in the satellite data and long‐term records are sparse. However, thickness observations and other satellite‐derived data indicate a 40% decline in thickness, due in large part to the loss of thicker, older ice cover. The changes in sea ice are happening faster than models have projected. With continued increasing temperatures, summer ice‐free conditions are likely sometime in the coming decades, though there are substantial uncertainties in the exact timing and high interannual variability will remain as sea ice decreases. The changes in Arctic sea ice are already having an impact on flora and fauna in the Arctic. Some species will face increasing challenges in the future, while new habitat will open up for other species. The changes are also affecting people living and working in the Arctic. Native communities are facing challenges to their traditional ways of life, while new opportunities open for shipping, fishing, and natural resource extraction. Significant progress has been made in recent years in understanding of Arctic sea ice and its role in climate, the ecosystem, and human activities. However, significant challenges remain in furthering the knowledge of the processes, impacts, and future evolution of the system.
Lightning attachment process involving connection of the downward negative leader to the lateral surface of the upward connecting leader

High‐speed video camera records, with a temporal resolution of 20 µs and a spatial resolution of 2.4 m per pixel, of a downward negative lightning flash that terminated on a 440 m high building are examined. The attachment process in this flash exhibited an unexpected behavior in that the downward leader tip connected to the lateral surface of the ~400 m upward connecting leader (UCL) below its tip. It appears that the effect of the downward leader on the UCL is significant, while the effect of the UCL on the downward leader is negligible, except for the final 80 µs preceding the beginning of the first return stroke. The ratio of speeds of the downward leader and the UCL tends to decrease with time, ranging from 1.8 to 0.12, although the lower 80–100 m or so of the UCL were too faint to allow speed measurements.
Wind‐driven spin‐up in eddy‐resolving ocean models formulated in isopycnic and isobaric coordinates

Wind-driven spin-up of the four-layer, quasi-isopycnic, eddy-resolving primitive equation model of Bleck and Boudra (1981) is compared with that obtained with a (numerically dissimilar) “pure” isopycnic coordinate model and an isobaric (i.e., quasi-Cartesian) coordinate model. In particular, the onset of hydrodynamic instabilities in the flow forced by a double-gyre wind stress pattern is studied. The spin-up processes associated with the isopycnic and quasi-isopycnic model are found to be similar, whereas the flow pattern produced by the quasi-Cartesian model deviates in the direction of Holland's (1978) and Holland and Lin's (1975a, b) two-layer solutions.
A monthly and latitudinally varying volcanic forcing dataset in simulations of 20th century climate

A new monthly volcanic forcing dataset is included in a coupled GCM for a more physically consistent treatment of the stratospheric sulfate aerosol history from explosive volcanism. The volcanic forcing is different from previous versions in that there is an individual evolution of the aerosol for each event. Thus the seasonal and latitudinal dependence of the volcanic aerosol can affect global climate in a more realistic way prior to the satellite period, compared to earlier volcanic forcing datasets. Negative radiative forcing from volcanic activity is greatest in the early 20th century prior to 1915 and in the late 20th century after 1960. The combination of volcanic and solar forcing contributes to an early‐20th century warming, followed by relative cooling in late 20th century. Consequently, the addition of natural forcing factors to the anthropogenic GHG forcing in late 20th century is required to simulate the observed late 20th century warming.