Miracle-dz/UniFAR-FTUs huggingface dataset:
Harmonic Stability in MMC-HVDC Applications Controlled as a Virtual Synchronous Machine

Along with the increased requirements of grid-forming assets, a thorough comprehension of the impact of these controls on the system’s harmonic stability gains more and more importance. Therefore, previous research contributed to understanding the admittance-shaping effects of the main control loops related to a converter controlled as a virtual synchronous machine. In extension to previous investigations, this paper focuses on the impact of implementation and design of the ac voltage controller. In light of dynamic performance requirements of power quantities, structural adjustments – namely, a power feed-forward - have been proposed in literature. However, these adjustments might influence the frequency-dependent behavior of modular multilevel converters controlled as a virtual synchronous machine. Therefore, the impact of these dynamics are derived analytically and evaluated by means of their admittance-shaping effects, too. A final summary classifies all admittance-shaping effects of structural and design related dynamics within virtual synchronous machine controlled modular multilevel converters.
LF Radio Receiver For Substation Intrusion Deterrent and Measurement Validation

In this paper, we implement non-contact, low frequency radio measurements of the local magnetic field within an electric substation to infer power grid parameters like current, frequency, and harmonic distortion. In particular, our receiver measures the 60 Hz emission and its harmonics with time resolution <1 second. The goal is to independently verify the state of the power grid to guard against certain types of attacks. Using a linear regression model, we can estimate the power grid parameters using our radio observations. Initial results indicate a correlation coefficient as high as 70% in estimating the three-phase current, and that the estimation accuracy is significantly improved by including higher harmonics.
Enhancing Conservation Voltage Reduction using Coordinated Control of Medium and Low Voltage Controllable Devices

A large amount of distributed energy resources (DERs) are integrated into distribution system. As the operating cycle of DERs are faster, legacy devices are not sufficient in mitigating the voltage issues occurred due to DERs in a distribution system. Hence, fast operating voltage controllable devices are integrated in both the medium and low voltage side of a distribution network. This motivates a coordinated control of all the voltage controllable device to achieve a desired objective. In this paper, a distribution optimal power flow (D-OPF) problem is proposed, which combines legacy devices and new medium voltage controllable devices for conservation voltage reduction (CVR). Next, the low voltage controllable device maintains the nodal voltage set-point obtained from D-OPF. The coordinated control of all the voltage controllable devices increase the energy savings in a network. The scalability of the proposed D-OPF is demonstrated using an actual utility feeder. The results validate the effectiveness of the proposed coordinated control for enhancing the energy savings.
The diversity of flow structures in felsic dykes

Abstract: Numerous structures and textures, which can be related to magma flow, were observed in felsic dykes intruding late Mesozoic granitoid plutons in the Jiaodong peninsula, in eastern Shandong province, eastern China. These flow structures may be classified into two categories, interior and peripheral. The former group includes magmatic bands, various types of folds (e.g. injection, sheath, similar and disharmonic folds), rotation of phenocrysts, magmatic foliation or lineation, and crenulation, whereas the latter includes hot tool marks and quarrying structures. Magmatic banding resulted from shearing of mingled magma during magma flow in the dykes. The magma seemed to flow rapidly, probably triggering turbulence in some thick dykes. Interaction at the contact between the hot, moving magma and the cold, stationary wallrock sometimes produced the peripheral structures. A few measurements of hot tool marks and of magmatic lineation reveal a roughly horizontal flow of magma within these dykes. For the dominant NE–SW-striking dyke set in the Laoshan granitoid pluton, the felsic magma probably ascended on or to the SW of the pluton to feed the dyke swarm, and then flowed laterally to drive the horizontal propagation of dykes.
Adaptation to a changing environment: the response of marshland communities to the late medieval 'crisis'

Abstract Coastal marshlands form one of the many distinctive landscapes - or pays - within the British Isles. Their reclamation generally began during the early medieval period, and by the 12th and 13th centuries they were extensively settled and used for mixed agriculture, much like the adjacent dryland areas. It would be expected that the late medieval climatic deterioration, population decline and its associated socio-economic changes would have led to a marked decline in the settlement of such physically challenging areas but this was not generally the case. This paper examines how the communities living in coastal marshlands responded to the increase in flooding, declining population and falling profits from agriculture through a combination of increased investment and agricultural innovation, and that these cultural responses can only be understood by placing these specific landscapes within their wider context.
Design of a distributed P2P-based content management middleware

There is an emerging need for content management systems (CMS) enabling collaborative development, administration, and distribution of content over the Internet. Many CMS solutions are currently based on a client/server architecture with a central server for storage and management. While such centralized systems simplify management with respect to data consistency, security, and accountability, they lack scalability and reliability. Pure peer-to-peer (P2P) network architectures are based on the assumption that no central server exists and has to be relied on, since peers collaboratively provide content and core system functionality that would be provided otherwise by a single server. A P2P-based CMS scales much better, since available system resources increase linearly with the number of participating peers. In addition, the availability of the system can be raised without much effort, by increasing the redundancy of content across the peer.
Testing the Woodcock-Harward image segmentation algorithm in an area of southern California chaparral and woodland vegetation

Abstract Vegetation maps were produced by applying a region-growing segmentation algorithm to Landsat Thematic Mapper (TM) data, and labelling the resulting segments or map polygons by overlay of a per-pixel classification and applying a plurality rule. Thus, each segment was assigned a vegetation class label based on the most frequently occurring pixels in the segment. The segmentation improved overall map accuracies by an average of 10 per cent relative to the underlying per-pixel classification for three subimages within a southern California montane watershed based on a comparison with photointerpreted maps. While it was hypothesized that including transformed slope aspect and image texture as input to the segmentation would improve map accuracy by creating segments corresponding more closely to vegetation stands, our results did not support these hypotheses. Further, performing the segmentation on principal components bands, or a vegetation index, did not improve results over the segmentation based o.
Host–guest relationships in rural tourism: evidence from two Portuguese villages

Rural tourism is receiving increasing interest, but not all areas have the same tourism potential, whereas evidence also reveals negative impacts on tourism. It is therefore important to analyse the tourism phenomenon at the local scale and understand a most important dimension of the rural tourism experience – social interaction. This is sought and appreciated, for distinct reasons, by both tourists and local communities, but little is still known about concrete interactions taking place, how these are interpreted, and may become more satisfactory for all involved. These questions are discussed based on results of an in-depth, qualitative approach on rural tourism in two Portuguese villages, comparing perspectives of hosts and guests, as well as of two distinct destination realities.
Comparison of Ground Penetrating Radar and Time-Domain Reflectometry as Soil Water Sensors

Robust and noninvasive techniques for in situ measurement of soil water content are essential for monitoring and research of many hydrologic processes. Although in situ measurement of soil water content by means of a soil's electric and dielectric properties has been explored extensively, the use of ground-penetrating radar (GPR) for this purpose is not well established. We compared the soil's dielectric constant as measured by GPR and time domain reflectometry (TDR) and its relationship to water content determined independently in auger holes. We propose a calibration equation relating soil water to GPR-measured dielectric constants. The difference in calibration equations between GPR and TDR was partially attributed to the difference in frequency ranges in which TDR and GPR operate and the zero offset of the GPR.
Development of an incised valley‐fill at an evolving rift margin: Pleistocene eustasy and tectonics on the southern side of the Gulf of Corinth, Greece

This study from the southern margin of the Gulf of Corinth documents a Late Pleistocene incised valley‐fill succession that differs from the existing facies models, because it comprises gravelly shoal‐water and Gilbert‐type deltaic deposits, shows strong wave influence and lacks evidence of tidal activity. The valley‐fill is at least 140 m thick, formed in 50 to 100 ka between the interglacials Marine Isotope Stage 9a and Marine Isotope Stage 7c. The relative sea‐level rise left its record both inside and outside the incised valley, and the age of the valley‐fill is estimated from a U/Th date of coral‐bearing deposits directly outside the palaeovalley outlet. Tectonic up‐warping due to formation of a valley‐parallel structural relay ramp contributed to the valley segmentation and limited the landward extent of marine invasions. The valley segment upstream of the ramp crest was filled with a gravelly alluvium, whereas the downstream segment accumulated fluvio‐deltaic deposits. The consecutive deltaic systems nucleated in the ramp‐crest zone, forming a bathymetric gradient that promoted the ultimate growth of thick Gilbert‐type delta. The case study contributes to the spectrum of conceptual models for incised valley‐fill architecture. Four key models are discussed with reference to the rates of sediment supply and accommodation development, and it is pointed out that not only similarity, but also all departures of particular field cases from these end‐member models may provide valuable information on the system formative conditions. The Akrata incised valley‐fill represents conditions of high sediment supply and a rapid, but stepwise development of accommodation that resulted from the spatiotemporal evolution of normal faulting at the rift margin and overprinted glacioeustatic signals. This study adds to an understanding of valley‐fill architecture and provides new insights into the Pleistocene tectonics and palaeogeography of the Corinth Rift margin.
Synthesizing multiple remote-sensing techniques for subglacial hydrologic mapping: application to a lake system beneath MacAyeal Ice Stream, West Antarctica

Abstract We present an analysis of the active hydrologic system of MacAyeal Ice Stream (MacIS), West Antarctica, from a synthesis of multiple remote-sensing techniques: satellite laser altimetry; satellite image differencing; and hydrologic potential mapping (using a satellite-derived DEM and a bedrock DEM from airborne radio-echo sounding). Combining these techniques augments the information provided by each one individually, and allows us to develop a protocol for studying subglacial hydrologic systems in a holistic manner. Our study reveals five large active subglacial lakes under MacIS, the largest of which undergoes volume changes of at least 1.0 km3. We discuss the hydrologic properties of this system and present evidence for links between the lakes. At least three of the lakes are co-located with sticky spots, i.e. regions of high local basal shear stress. We also find evidence for surface elevation changes due to ice-dynamic effects (not just water movement) caused by changes in basal resistance. Lastly, we show that satellite radar altimetry is of limited use for monitoring lake activity on fast-flowing ice streams with surfaces that undulate on ∼10 km length scales.
Gas-particle interactions above a Dutch heathland: I. Surface exchange fluxes of NH 3 , SO 2 , HNO 3 and HCl

Abstract. A field measurement campaign was carried out over a Dutch heathland to investigate the effect of gas-to-particle conversion and ammonium aerosol evaporation on surface/atmosphere fluxes of ammonia and related species. Continuous micrometeorological measurements of the surface exchange of NH3, SO2, HNO3 and HCl were made and are analyzed here with regard to average fluxes, deposition velocities (Vd), canopy resistances (Rc) and canopy compensation point for NH3. Gradients of SO2, HNO3 and HCl were measured with a novel wet-denuder system with online anion chromatography. Measurements of HNO3 and HCl indicate an Rc of 100 to 200 s m-1 during warm daytime periods, probably at least partly due to non-zero acid partial pressures above NH4NO3 and NH4Cl on the leaf surfaces. Although it is likely that this observation is exacerbated by the effect of the evaporation of airborne NH4+ on the gradient measurements, the findings nevertheless add to the growing evidence that HNO3 and HCl are not always deposited at the maximum rate. Ammonia (NH3) fluxes show mainly deposition, with some periods of significant daytime emission. The net exchange could be reproduced both with an Rc model (deposition fluxes only) using resistance parameterizations from former measurements, as well as with the canopy compensation point model, using parameterizations derived from the measurements. The apoplastic ratio of ammonium and hydrogen concentration (Γs=[NH4+]/[H+]) of 1200 estimated from the measurements is large for semi-natural vegetation, but smaller than indicated by previous measurements at this site.
Attribute extraction: An important application in any detailed 3-D interpretation study

Three‐dimensional seismic is playing an increasingly important role in appraisal and development planning. Whereas, at first, 3 D data sets were aimed at analyzing the structural style and the mapping of complex fields, more recently, 3-D seismic has proved its value in defining details at reservoir level. Pore content, reservoir facies and very small faults which may impede fluid movement can often be mapped confidently with 3-D seismic.
Steady State DNAPL Dissolution in Three-Dimensional Fractured Sandstone Network Experiments

AbstractThe distribution of residual dense nonaqueous phase liquid (DNAPL) in the subsurface plays a critical role in the DNAPL dissolution kinetics. However, measuring residual DNAPL at the field scale in fractured bedrock settings is generally impractical. This research uses a three-dimensional (3D), bench-scale, fractured-rock network comprised of low-porosity sandstone to evaluate the dissolution kinetics of tetrachloroethylene (PCE) DNAPL at residual saturation during ambient groundwater conditions. To our knowledge, this work presents the first experiments to investigate DNAPL dissolution in 3D bench-scale fractured systems. DNAPL dissolution in the relatively uniform fracture network was evaluated and described using an effective parameter, the bulk mass transfer coefficient (KL). Results from dissolution experiments revealed a positive, statistically significant correlation between KL and DNAPL-water interfacial area, and between KL and DNAPL saturation, analogous to porous media experiments. Whil.
Predicted and Measured Drainable Porosities for Field Soils

ABSTRACT EXPERIMENTS were conducted on large field cores to determine the relationship between drainage volume and water table depth for five soils. The measured drainage volumes were less than pre-dicted from the soil water characteristics for three soils, but were in good agreement for the other two. Drainable porosities were calculated from both theoretical and experimental drainage volume-water table depth relationships by assuming that the un-saturated zone is essentially 'drained to equilibrium, with the water table. The experimental drainable porosities thus obtained were less than predicted. Drainable porosities for drainage in two-dimensions were calculated from experimental results for one-dimension by assuming an elliptical water table profile. These results gave nearly constant drainable porosities for the layered soils and a variable drain-able porosity for Wagram, a homogeneous, sandy soil.
(POSTER) Insights from Executing TinyML Models on Smartphones and Microcontrollers

In this paper, we empirically compare the system-level performances of executing a machine learning task on a resource-constrained IoT device and compare its performance to offloading the task to a more capable device, a smartphone. Our results indicate that although the resource-constrained device cannot run complex machine learning models, they can provide reasonable accuracy using similar models that can load on their memory. For running simpler models on the microcontroller, the best case accuracy for the machine learning task was 94.32% (SD: 1.7%). Furthermore, local computation resulted in almost 50% lesser current draw as compared to the offloading. These observations make a case for adopting an adaptive approach to ensure that applications meet the energy-accuracy-latency balance.
Factors controlling the rate of CaCO3 precipitation on Great Bahama Bank

Measurements by Langdon et al. [2000] in the man‐made mesocosm coral reef at Biosphere 2's ocean reveal a strong dependence of calcification rate on the degree of supersaturation of CaCO3 in seawater. A similar trend was previously encountered on the Bahama Banks, where Halimeda and other calcifiers are likely responsible for aragonite precipitation [Broecker and Takahashi, 1966]. In this paper we compare these two sets of results and conclude that the dependence on saturation state is significant but less strong in the Bahamas. However, it must be kept in mind that to some extent, the reduction in CaCO3 precipitation on the Bahama Banks may be due to impact of higher salinity on the growth of the calcifying algae. However, if, as many sedimentologists are convinced, the precipitation of CaCO3 on the Bahama Banks is inorganic [Macintyre and Reid, 1992; Milliman et al., 1993], then the comparison of the Bahamas and Biosphere 2 results for dependence of calcification rate on saturation state is telling us something quite different.
Amoebiasis and probiotics: perspectives on complementary treatment

Amoebiasis is a disease caused by the protozoan parasite Entamoeba histolytica that has a worldwide geographic distribution, with a higher prevalence in developing countries where social and sanitary conditions are considerably precarious. Amoebiasis can be accompanied by severe clinical manifestations such as amoebic colitis and amoebic liver abscess, aggravating the host's condition, with death as one of the consequences. Several health actions and pharmacological strategies have been made to prevent the infection and possible complications of this disease, and have achieved success in containing the disease in most patients. However, some medications such as metronidazole can also cause serious complications to the individual because of their potential hepatotoxic effect in addition to producing other side effects. Research directed towards an alternative and effective treatment for amebiasis has been conducted. The use of probiotics has been highlighted as a promising treatment against Entamoeba spp. In this review, we will address the prospects of using probiotics as a treatment for amoebiasis patients. In addition, we will provide information on the biology of Entameba spp. ; the clinical manifestations of amoebiasis and a perspective of the use of Weissella paramesenteroides as a possible treatment.
Perspectives on Sexual and Reproductive Health

Published four times a year, Perspectives on Sexual and Reproductive Health includes original research, special reports and commentaries on the latest developments in the field of sexual and reproductive health, as well as staff-written summaries of recent findings in the field. Perspectives has a wide range of readers, including researchers, policymakers, program administrators and service providers in the United States and around the world.
The distribution of potassium and sodium between the solution and the solid phase in a ternary (K–Na–Ca) system

Reduction of sodicity hazards in soils irrigated with waste water can be achieved through the replacement of the Na salts (mainly NaCl), used in water softening and other industrial processes, with potassium salts. We studied the effect of equilibrating a grumusol (Typic Chromoxerert) with solutions of differing potassium adsorption ratio (PAR) and sodium adsorption ratio (SAR), within the range expected in waste water, on the distribution of K and Na between the solution and the solid phase. The K distribution did not depend on the level of Na in the solution, but the distribution of Na between the 2 phases depended strongly on the PAR of the solution. For SAR 10 solutions, ESP decreased from 11.1 to 7.8 as PAR increased from 0 to 4. Gapon selectivity coefficients for Na, calculated separately for each PAR level, also decreased with increasing PAR. The Na distribution between solution and solid phase in a ternary (K–Na–Ca) system could not therefore be predicted from the Gapon selectivity coefficient obtained from a binary (Na–Ca) system.
Spring evolution of Arabian Sea High in the Indian Ocean

The seasonal formation of a large anticyclonic circulation pattern, Southern Arabian Sea High (SAH), appears in the southern Arabian Sea during the northeast monsoon. SAH is studied on the basis of the recent observations that include the World Ocean Circulation Experiment (WOCE)/Tropical Ocean-Global Atmosphere (TOGA) experiment drifting buoys along with TOPEX/ERS-2 satellite altimeter data in conjunction with the climatological hydrography observations. The SAH forms west of the Laccadive High (LH), first appears in January, and grows rapidly in situ to form a well-developed anticyclonic eddy, extending across the southern Arabian Sea by March. The center of the eddy is ∼65°E, 5°N. The SAH is bounded by a strong eastward current to the north and a weak southward flow between 65° and 70°E, which separates SAH from the LH. The westward flowing North Equatorial Current (NEC) is on the southern flank. A strong northward flow along 55°E during January and February marks the western boundary. SAH propagates westward as a Rossby wave between March and April. The arrival of SAH in the western boundary in April is accompanied by intensification of current along the coast of Somalia. In May, part of the SAH has subsequently moved northward to form an anticyclonic eddy with an apparent center 13°N, 53°E in the vicinity of the Gulf of Aden (Gulf of Aden Eddy (GAE)). The GAE extends horizontally nearly 600 km (along 13°) and is vertically extended down through the upper main thermocline to ∼250 m. Comparisons of hydrography, buoy, and altimetry reveal a good agreement in eddy size, location, and time of appearance of the GAE.