bluuebunny/crossref_metadata_2025 huggingface dataset:
Triaxial Testing’s 1/6th Rule: Particle-Continuum Analysis of Granular Stability during Compression
Authors: Hoffman Peter
Published: June 2019

The 1/6th Rule of Triaxial Testing says that particles larger than 1/6th the diameter of the specimen will skew test results when not discarded. Although this rule is documented in the procedures of government laboratories, its origin is obscure. In this paper, the rule is derived as a corollary of granular stability. The stability derivation involves particle-continuum analysis. However, instead of a discrete element formulation or Cosserat mechanics, this paper uses the classical solution of Sokolovskii that is the modern basis of Terzaghi bearing capacity theory. Stability of a soil particle is addressed within the continuum by matching leading terms of series expansions, which is also known as the singular perturbation method. This finding is similar to previous derivations involving deformation of geosynthetic reinforced soil.
Assessing the impact of vertical heat exchangers on the response of a retaining wall
Authors: Sailer Eleonora , Taborda David M. G. , Zdravkovic Lidija , Potts David M.
Published: June 2019

Shallow geothermal energy systems, e.g. borehole heat exchangers or thermo-active structures, provide sustainable space heating and cooling by exchanging heat with the ground. When installed within densely built urban environments, the thermo-hydro-mechanical (THM) interactions occurring due to changes in ground temperature, such as soil deformation and development of excess pore water pressures, may affect the mechanical behaviour of adjacent underground structures. This paper investigates the effects of vertical heat exchangers installed near a deep basement by performing fully coupled THM finite element analyses using the Imperial College Finite Element Program. Different heat exchanger configurations are considered and their influence on the response of the basement wall is assessed in two-dimensional plane strain analyses, where different methods of modelling the heat sources in this type of analysis are employed to evaluate their effect on the temperature field and the non-isothermal soil response.
Cracking behaviour of fine-grained soils: from laboratory testing to numerical modelling
Authors: Gerard Pierre , Murray Ian , Tarantino Alessandro
Published: June 2019

Many experimental evidences suggest that desiccation cracks in clay initiate as a result of the mobilization of soil tensile strength. However this mechanical approach disregards the cohesionless and effective stress-dependent behaviour of fine-grained soil. On the other hand recent findings in the literature suggest that effective stress-dependent shear failure criteria would be appropriate to explain the mechanisms of desiccation cracking for tensile total stress states. This work aims at assessing the validity of a shear failure criterion to predict the onset of cracking in clay forms exposed to air drying. Clay forms of various geometries were experimentally subjected to non-uniform hydraulic and mechanical boundary conditions. Time and location for crack initiation are monitored using a digital camera. Cracking experiments are then modelled in a hydro-mechanical framework using an effective-stress shear failure criterion. The comparison of simulations with experimental results for both the time and the location of cracking allows assuming that cracking occurs due to failure in shearing.
The potential of seismic cross-hole tomography for geotechnical site investigation
Authors: Hing Ng Yannick Choy , Danovan William , Ku Taeseo
Published: June 2019

Seismic cross-hole tomography has been commonly used in oil and gas exploration and the mining industry for the detection of precious resources. For near-surface geotechnical site investigation, this geophysical method is relatively new and can be used to supplement traditional methods such as the standard penetration test, coring and sampling, thus improving the effectiveness of site characterization. This paper presents a case study which was carried out on a reclaimed land in the Eastern region of Singapore. A seismic cross-hole test was performed by generating both compressional waves and shear waves into the ground. The signals were interpreted by using first-arrival travel time wave tomography and the arrival times were subsequently inverted using Simultaneous Iterative Reconstruction Technique (SIRT). A comparison with the borehole logging data indicated that P-wave velocity model cannot provide sufficient information about the soil layers, especially when the ground water table is near the surface. The S-wave velocity model seemed to agree quite well with the variation in the SPT-N value and could identify to a certain extent the interface between the different soil layers. Finally, P-wave and S-wave velocities are used to compute the Poisson's ratio distribution which gave a good indication of the degree of saturation of the soil.
Fragebogenerhebung zur Erfassung des Status Quo bewegungstherapeutischer Interventionen in deutschen zertifizierten Krebszentren
Authors: Kowarik Evelyn , Wirtz Petra , Steinhauser Susanne , Elter Thomas , Baumann Freerk Theeagnus
Published: June 2019

Hintergrund Umfassende Erkenntnisse zu bewegungstherapeutischen onkologischen Versorgungsstrukturen in Deutschland liegen zurzeit nicht vor. Ziel dieser Umfrage war eine Infrastruktur- und Angebotsanalyse der Bewegungsinterventionen an bundesdeutschen Krebszentren.

Methoden 2015 wurden alle deutschen zertifizierten Krebszentren (N=756) mittels Fragebogen zu bestehenden bewegungstherapeutischen Angeboten befragt und mit definierten infrastrukturelle Mindestanforderung zur Umsetzung gezielter Bewegungstherapie verglichen.

Ergebnisse 132 Krebszentren wurden in die Auswertung eingeschlossen. 90,9% der Zentren (N=120) bieten mindestens eine Form von Physio- oder Sporttherapie an. 22,7% der befragten Zentren erfüllen die infrastrukturellen Mindestanforderungen.

Schlussfolgerungen Neueste wissenschaftliche Erkenntnisse im Zuge einer optimalen therapeutischen Trainingssteuerung und damit evidenzbasierten Versorgung scheinen zurzeit schwer umsetzbar, was die Etablierung einer Leitlinie zu onkologischer Sport- und Bewegungstherapie notwendig macht.
Longitudinal Course of Short-Term Variation and Doppler Parameters in Early Onset Growth Restricted Fetuses
Authors: Baier Friederike , Weinhold Leonie , Stumpfe Florian M. , Kehl Sven , Pretscher Jutta , Bayer Christian M. , Topal Nalan , Pontones Constanza , Mayr Andreas , Schild Ralf , Schmid Matthias , Beckmann Matthias W. , Faschingbauer Florian
Published: June 2019

Purpose To evaluate the longitudinal pattern of fetal heart rate short term variation (STV) and Doppler indices and their correlation to each other in severe growth restricted (IUGR) fetuses.

Materials and Methods In this retrospective study, pregnancies with a birth weight below the 10th percentile, born between 24 and 34 gestational weeks with serial Doppler measurements in combination with a computerized CTG (cCTG) with calculated STV were included. Longitudinal changes of both Doppler indices and STV values were evaluated with generalized additive models, adjusted for gestational age and the individual. For all measurements the frequency of abnormal values with regard to the time interval before delivery and Pearson correlations between Doppler indices and STV values were calculated.

Results 41 fetuses with a total of 1413 observations were included. Over the course of the whole study period, regression analyses showed no significant change of STV values (p = 0.38). Only on the day of delivery, a prominent decrease was observed (mean STV d28-22: 7.97 vs. mean STV on day 0: 6.8). Doppler indices of UA and MCA showed a continuous, significant deterioration starting about three weeks prior to delivery (p = 0.007; UA and p < 0.001, MCA). Correlation between any Doppler index and STV values was poor.

Conclusion Fetal heart rate STV does not deteriorate continuously. Therefore, cCTG monitoring should be performed at least daily in these high-risk fetuses. Doppler indices of umbilical artery (UA) and middle cerebral artery (MCA), however, showed continuous deterioration starting about 3 weeks prior to delivery.
Auswirkungen der vorübergehend fehlenden Genehmigungsfähigkeit für Zwangsbehandlung in Baden-Württemberg: nicht weniger Medikamente, aber längere Freiheitsentziehung
Authors: Steinert Tilman , Keyssner Simon , Schmid Peter , Flammer Erich
Published: June 2019

Hintergrund Nach den Entscheidungen des Bundesverfassungsgerichts von 2011 und des Bundesgerichtshofs von 2012 waren Zwangsbehandlungen in Baden-Württemberg vorübergehend für sieben Monate nicht genehmigungsfähig. Auswertungen aus Routinedaten hatten gezeigt, dass bei einer kleinen Gruppe von Patientinnen und Patienten aggressive Übergriffe, Fixierungen und Isolierungen signifikant zunahmen und danach wieder auf das vorige Niveau zurückgingen. Die vorliegende Studie sollte mittels der Analyse von Krankenakten aus sechs Klinikstandorten klären, ob Verweigerung der angeordneten Medikation häufiger war und wie häufig eine antipsychotische Medikation ohne die Möglichkeit des Zwangs realisiert wurde.

Methode In einem quasi-experimentellen intraindividuellen longitudinalen Vergleich bezogen wir alle Patientinnen und Patienten mit schizophrenen und manischen Störungen ein, die eine Behandlungsepisode sowohl in der Zeit ohne zulässige Zwangsmedikation als auch in einem Zeitraum gleicher Länge im Vorjahr aufwiesen (N = 174).

Ergebnisse In der Periode ohne Möglichkeit einer Zwangsbehandlung waren die Patientinnen und Patienten im Durchschnitt signifikant häufiger (+ 26 %), aber nur insignifikant länger untergebracht, Aufenthaltsdauer und Anzahl der Fixierungen blieben unverändert, Isolierungen verdoppelten sich, einige Patienten hatten sehr lange keinen Ausgang und wurden häufig wieder aufgenommen. Medikamentenverweigerung war signifikant häufiger (+130 %, p < .001). Dennoch unterschied sich der Anteil der Patienten, die im Verlauf ein Antipsychotikum einnahmen, nicht (96,0 bzw. 96,6 %), die Dosis in Chlorpromazin-Einheiten bei Entlassung war in der Periode ohne Zwangsbehandlung tendenziell sogar höher (+7,9 %, p = 0.07). Die Unterschiede betrafen gleichermaßen freiwillig und unfreiwillig behandelte Patienten.

Schlussfolgerungen Ohne die Möglichkeit der Genehmigung einer Zwangsbehandlung nahmen anhaltende Medikamentenverweigerung und Freiheitseinschränkungen verschiedener Art zu, eine orale antipsychotische Behandlung wurde in fast allen Fällen realisiert.
Nerve Ultrasonography as an Additive Tool to Clinical Examination and Electrodiagnostics in Sporadic Mononeuritis – Imaging is the Key
Authors: Winter Natalie , Dammeier Nele , Schäffer Eva , Bornemann Antje , Stahl Jan-Hendrik , Herlan Stephan , Schuhmann Martin Ullrich , Grimm Alexander
Published: June 2019

Purpose Sporadic mononeuropathies without trauma or compression are challenging to diagnose. Nerve ultrasound has recently proven its usefulness in the diagnosis of traumatic neuropathies, tumors and polyneuropathies. However, its role in mononeuropathies currently remains unclear. We describe ultrasonography follow-up results in 12 patients with suggested spontaneous, monophasic mononeuritis without signs of generalization.

Materials and Methods Nerve conduction studies (NCS), ultrasonography of the affected nerves and the contralateral side, laboratory analysis, and if possible magnetic resonance imaging (MRI) of the affected nerves were established in all patients at onset. In one patient, additive nerve biopsy was performed. In all patients, ultrasonography was repeated after immunotherapy.

Results An infectious pathogen of neuritis was not found in any patient. All but one patient showed predominant axonal nerve damage in NCS, whereas ultrasonography and MRI revealed fascicular and/or overall cross-sectional area (CSA) enlargement or T2 hyperintensity of the affected nerve segments, suggesting an inflammatory background of the neuropathy. Most patients showed significant clinical amelioration of symptoms under treatment (75.0 %) and consequently a decrease in CSA/fascicle enlargement over time (77.8 %).

Conclusion Ultrasonography and MRI of the nerves revealed enlargement in patients with mononeuropathy of axonal NCS pattern of unknown origin. Ultrasonography can facilitate the therapeutic decision for immunotherapy. Next to nerve trauma, nerve tumors and nerve entrapments, ultrasonography reliably shows nerve enlargement in the case of inflammation and therefore could further enrich neurophysiology. Nerve imaging might serve as a follow-up tool by observing a decrease in nerve enlargement and improved function.
The Impact of Ethinyl Estradiol on Metformin Action on Prolactin Levels in Women with Hyperprolactinemia
Authors: Krysiak Robert , Szkróbka Witold , Okopień Bogusław
Published: June 2019

Background Metformin reduced prolactin levels only in women with hyperprolactinemia.

Objective The purpose of this case-control study was to compare metformin action on lactoctrope function between women receiving oral contraceptive pills and women not using hormonal contraception.

Methods The study included two groups of matched women with elevated prolactin levels and new-onset prediabetes or diabetes. The first group consisted of 20 women using oral contraceptive pills for at least 12 months before entering the study, while the second group included 20 patients not using any hormonal contraception. Over the whole study period, all women were treated with metformin (1.7–3 g daily). Circulating levels of glucose, insulin, prolactin, thyrotropin, free thyroid hormones, adrenocorticotropic hormone, gonadotropins and insulin-like growth factor-1 were measured at the beginning and at the end of the study (16 weeks later).

Results Thirty-eight patients completed the study. Metformin reduced plasma glucose levels and improved insulin sensitivity but the latter effect was stronger in women receiving oral contraceptive pills than in women not using any contraception. Although metformin treatment decreased plasma prolactin levels in both study groups, this effect was stronger in women taking oral contraceptive pills. Only in this group of women, metformin increased plasma luteinizing hormone levels. The changes in plasma prolactin correlated with their baseline insulin sensitivity and the effect of metformin on insulin sensitivity. Metformin did not affect plasma levels of thyrotropin, free thyroxine, free triiodothyronine, follicle-stimulating hormone, adrenocorticotropic hormone and insulin-like growth factor-1.

Conclusions The obtained results suggest that the effect of metformin on overactive lactotropes depends on estrogen levels.
Effective participatory science education in a diverse Latin American population
Authors: Ferreira Leonardo M. R. , Carosso Giovanni A. , Montellano Duran Natalia , Bohorquez-Massud Soad V. , Vaca-Diez Gustavo , Rivera-Betancourt Laura Ines , Rodriguez Yara , Ordonez Dalila G. , Alatriste-Gonzalez Diana K. , Vacaflores Aldo , Gonzalez Auza Lilian , Schuetz Christian , Alvarado-Arnez Lucia Elena , Alexander-Savino Carolina V. , Gandarilla Omar , Mostajo-Radji Mohammed A.
Published: June 2019

Particular challenges exist for science education in the developing world, where limited resources require curricula designed to balance state-of-the-art knowledge with practical and political considerations in region-specific contexts. Project-based biology teaching is especially difficult to execute due to high infrastructural costs and limited teacher training. Here, we report the results of implementing short, challenging, and low-cost biology courses to high school and college students in Bolivia, designed and taught in collaboration between scientists from developed nations and local science instructors. We find our approach to be effective at transmitting advanced topics in disease modeling, microscopy, genome engineering, neuroscience, microbiology, and regenerative biology. We find that student learning through this approach was not significantly affected by their background, education level, socioeconomic status, or initial interest in the course. Moreover, participants reported a heightened interest in pursuing scientific careers after course completion. These results demonstrate efficacy of participatory learning in a developing nation, and suggest that similar techniques could drive scientific engagement in other developing economies.
Nanotransfer-printed stamps allow fabrication of top-contact nanogap electrodes
Authors: Liebendorfer Adam
Published: June 2019

Molecular beam epitaxy and nanotransfer-printing pave way for depositing electrodes directly on top of nanoscale objects, providing a way to integrate the electrodes with external testing.
Rosiglitazone increases expression of steroidogenic acute regulatory protein and progesterone production through PPARγ–EGFR–ERK1/2 in human cumulus granulosa cells
Authors: Pogrmic-Majkic Kristina , Kosanin Gordana , Samardzija Nenadov Dragana , Fa Svetlana , Stanic Bojana , Trninic Pjevic Aleksandra , Andric Nebojsa
Published: June 2019

The mechanism by which rosiglitazone (ROSI: a thiazolidinedione (TZD)) affects steroid production in undifferentiated human granulosa cells is not known. In this study, cultured human cumulus granulosa cells were exposed to ROSI and pharmacological inhibitors of the extracellular signal-regulated kinase 1/2 (ERK1/2), epidermal growth factor receptor (EGFR) and peroxisome proliferator-activated receptor gamma (PPARγ) signalling pathways. Expression of progesterone biosynthetic enzymes, PPARγ and PPARα, progesterone production and ERK1/2 activation were analysed. After 48h, 30μM ROSI increased STAR, 3βHSD and PPARγ mRNA and elevated progesterone production in human cumulus granulosa cells. Addition of ERK1/2 (U0126), EGFR (AG1478) and PPARγ (GW9662) inhibitors prevented the ROSI-induced STAR mRNA expression and progesterone production after 48h. Inhibition of PPARγ, but not EGFR or ERK1/2, decreased the PPARγ mRNA levels induced by ROSI in human cumulus granulosa cells after 48h. On the other hand, U0126 and GW9662 prevented the ROSI-induced increase in PPARγ transcripts after 6h. Western blot analysis showed that ROSI induced a rapid ERK1/2 activation, which was prevented by inhibition of ERK1/2, EGFR and PPARγ in human cumulus granulosa cells. Overall, these data suggested that PPARγ, EGFR and ERK1/2 were involved in the stimulatory effect of ROSI on STAR expression and progesterone production in undifferentiated human cumulus granulosa cells.
The ethnopragmatics of Akan advice
Authors: Agyekum Kofi
Published: June 2019

This paper discusses Akan Advice under ethnopragmatics. It adopts persuasion, speech acts of directives and expressives, and Akan proverbs to discuss advice with the insight from Akan culture. The adviser expresses some feelings and emotions and directs the advisee to act and behave towards the benefits of the individual, the group or society. The paper taps data from participant observations and audio taped recordings at arbitrations, marriage and naming ceremonies. There is another data from Adi’s (1973) Akan literature book, Brako that covers pieces of advice on travelling, settlement and occupation. The Akan texts are translated into English and analysed. The analysis covers semantics, pragmatics, stylistic devices, and proverbs.
What keeps diaspora from contributing to peace processes? Exploring diaspora online narratives of homeland conflict
Authors: Martin Michelle
Published: June 2019

Politically active diaspora are increasingly recognized as key stakeholders in homeland peace processes, driven in large part by the globalization of communication technologies. Previous research has identified ways that diaspora contribute to peace processes in their countries of origin, or foment conflict. This study seeks to fill a gap in the literature regarding factors that influence diaspora contributions using Rwanda as a case study. Status posts from public and anonymous Facebook and Twitter accounts of self-identified Rwandan diaspora living in the Global North. Thematic analysis and methods drawn from virtual ethnography revealed several themes that were consistent with the literature on conflict-generated diaspora typology related to ethnic identity, ethnic reconciliation, victim status and motivations framed in human rights terms. The results highlight several dynamics that can potentially serve as barriers to diaspora positive engagement, as well as the enduring nature of ethnic conflict.
Time-dependent kinetic analysis of trapped electrons in a magnetically expanding plasma
Authors: Kim June Young , Jang Jae Young , Chung K S , Chung Kyoung-Jae , Hwang Y S
Published: June 2019

A deep understanding of the kinetic properties of the electrons in a magnetic nozzle (MN), which is attracting attention as an acceleration stage for thrusters, is of great significance as it directly contributes to the development of the MN performance. In the sense that a conversion of the electron momentum to the ion kinetic energy determines the characteristics of the MN, fundamental research on the kinetic feature of a magnetically expanding plasma has focused on the spatial distribution of the electron properties and proposed directions to the desired application. Unlike the common perception of this importance, various research groups have proposed contradictory arguments based on their theoretical approaches regarding the ion beam acceleration from the viewpoint of heat flow of electrons. We point out that the main reason for the absence of a theoretical consensus for the nozzle efficiency improvements arises from the lack of the clear interpretation of the plasma properties by focusing only on the final state of the electrons. In this Letter, time-resolved measurement of the electron energy distributions has been performed to grasp a detailed series of expansion processes. It has been revealed that the effective potential well gradually formed by the self-generated electric field acts as a limiting factor in the motion of electrons; this effect attributes to the changes of the electron energy distribution represented as the accumulation of the trapped electrons. The accumulation over the entire region diminishes the degree of the cooling rate of a system and decreases the electric field in the downstream region initially generated by the adiabatic expansion. The present study emphasizes that the kinetic features of an MN are strongly affected by the non-stationary motion of the trapped electrons; thus, the temporal behavior of the trapped electrons must be considered for prediction and analysis of nozzle performances.
Fabrication, characterization and micromechanics modeling of the electrical conductivity of reduced graphene oxide/aramid nanofiber nanocomposites
Authors: Zhou Tianyang , Boyd James G , Loufakis Dimitrios , Lutkenhaus Jodie L , Lagoudas Dimitris C
Published: June 2019

Graphene-based materials with high graphene concentration are of great interest for multifunctional, structural electrode materials that simultaneously store electrical energy and carry structural loads. Graphene-based materials can have a high electrochemically active surface area, high electrical conductivity, and good stiffness and strength. Published analytical studies of electrical conductivity are mostly focused on graphene-based polymer nanocomposites with very low concentrations of conductive fillers, for percolation purposes. In the research reported herein, reduced graphene oxide (rGO) and aramid nanofiber (ANF) nanocomposite films with higher concentrations of rGO, up to 100 wt% rGO, were fabricated and characterized for their electrical conductivity. In addition, a hybrid micromechanical and phenomenological model of electrical conductivity was developed to include the effects of rGO waviness and conductivity, volume fraction of ANF, random orientation of rGO and ANFs, interphase thickness and interphase conductivity. The experimentally measured in-plane conductivity of rGO/ANF nanocomposite films decreases exponentially with the addition of ANFs. For example, the experimental in-plane conductivity of rGO/ANF nanocomposite films was increased 30-fold by decreasing the ANF loading from 25 wt% to 0 wt%. This exponential relationship can be explained by the model proposed. The model showed that the influence of the interphase thickness and interphase conductivity was more significant than that of waviness. The effective in-plane conductivity changed by 20% when the waviness was decreased from maximum observed value to minimum. The effective in-plane conductivity decreased by two orders of magnitude when the interphase thickness was changed from 0 to 0.5 nm and the interphase conductivity was 0.09 S m−1. The model results agreed with the experimental data when the interphase thickness and conductivity vary with the volume fraction of rGO. The addition of ANFs is significant due to the influence it has on the microstructure of the composite and the interphase structure and conductivity. This model can be used for composites with coated fibers or continuous polymeric matrix by adjusting the interphase morphology.
What do we know about soil carbon destabilization?
Authors: Bailey Vanessa L , Pries Caitlin Hicks , Lajtha Kate
Published: June 2019

Most empirical and modeling research on soil carbon (C) dynamics has focused on those processes that control and promote C stabilization. However, we lack a strong, generalizable understanding of the mechanisms through which soil organic carbon (SOC) is destabilized in soils. Yet a clear understanding of C destabilization processes in soil is needed to quantify the feedbacks of the soil C cycle to the Earth system. Destabilization includes processes that occur along a spectrum through which SOC shifts from a ‘protected’ state to an ‘available’ state to microbial cells where it can be mineralized to gaseous forms or to soluble forms that are then lost from the soil system. These processes fall into three general categories: (1) release from physical occlusion through processes such as tillage, bioturbation, or freeze-thaw and wetting-drying cycles; (2) C desorption from soil solids and colloids; and (3) increased C metabolism. Many processes that stabilize soil C can also destabilize C, and C gain or loss depends on the balance between competing reactions. For example, earthworms may both destabilize C through aggregate destruction, but may also create new aggregates and redistribute C into mineral horizon. Similarly, mycorrhizae and roots form new soil C but may also destabilize old soil C through priming and promoting microbial mining; labile C inputs cause C stabilization through increased carbon use efficiency or may fuel priming. Changes to the soil environment that affect the solubility of minerals or change the relative surfaces charges of minerals can destabilize SOC, including increased pH or in the reductive dissolution of Fe-bearing minerals. By considering these different physical, chemical, and biological controls as processes that contribute to soil C destabilization, we can develop thoughtful new hypotheses about the persistence and vulnerability of C in soils and make more accurate and robust predictions of soil C cycling in a changing environment.
Seasonal hydroclimatic ensemble forecasts anticipate nutrient and suspended sediment loads using a dynamical-statistical approach
Authors: Sharma Sanjib , Gall Heather , Gironás Jorge , Mejia Alfonso
Published: June 2019

Subseasonal-to-seasonal (S2S) water quantity and quality forecasts are needed to support decision and policy making in multiple sectors, e.g. hydropower, agriculture, water supply, and flood control. Traditionally, S2S climate forecasts for hydroclimatic variables (e.g. precipitation) have been characterized by low predictability. Since recent next-generation S2S climate forecasts are generated using improved capabilities (e.g. model physics, assimilation techniques, and spatial resolution), they have the potential to enhance hydroclimatic predictions. Here, this is tested by building and implementing a new dynamical-statistical hydroclimatic ensemble prediction system. Dynamical modeling is used to generate S2S flow predictions, which are then combined with quantile regression to generate water quality forecasts. The system is forced with the latest S2S climate forecasts from the National Oceanic and Atmospheric Administration’s Climate Forecast System version 2 to generate biweekly flow, and monthly total nitrogen, total phosphorus, and total suspended sediment loads. By implementing the system along a major tributary of the Chesapeake Bay, the largest estuary in the US, we demonstrate that the dynamical-statistical approach generates skillful flow, nutrient load, and suspended sediment load forecasts at lead times of 1–3 months. Through the dynamical-statistical approach, the system comprises a cost and time effective solution to operational S2S water quality prediction.
An overview of handheld sun photometer measurements of atmospheric aerosols in New Orleans, Louisiana: A case study of the Xavier university study site
Authors: Bradley M , Sevalia B , Gasseller M
Published: June 2019

Aerosol optical depth (AOT) was measured at Xavier University of Louisiana (XULA, 29.96° N, 90.11° W and 3m above sea level) using a GLOBE handheld sun photometer. The measurements were done at two different wavelengths, 505nm and 625nm. The measured values were used to extrapolate the AOT values for wavelengths 667nm, 551nm, 532nm and 490nm at the XULA site. The measured and calculated AOT values were then compared with values from the nearest AERONET station at Wave CIS site 6 (AERONET, 28.87° N, 90.48° W and 33m above sea level), which is 60 miles south of XULA. In this study we tracked the annual and daily variations of AOT for a 12-month period from September 2017 to August 2018. These data show good qualitative agreement between the two stations in the 12-month period. Both sets of data show distinct peaks in February and May. Both sets of data show low AOT values in the winter months and high AOT values in the summer months. The hourly AOT variations averaged over the 12-month period was also investigated for the XULA site. The data show two peaks, one at 9:00 am and another at 3:00pm. We also compared AOT data from two independently calibrated GLOBE sun photometers at the XULA site. The data show that the two instruments are in excellent agreement. The R-squared value for the 505nm channel is 0.92 and the R-squared value for the 625nm channel is 0.95.
Experimental investigation of hydrodynamics and heat transfer of sphere cooling using air/water mist two phase flow
Authors: Abed A H , Shcheklein S E , Pakhaluev V M
Published: June 2019

To improve the cooling performance for the future generation of gas-cooled equipment, experimental studies on air/water mist heat transfer of single sphere inside a cylindrical channel have been carried out with an aim to investigate the heat transfer enhancement by suspending tiny water mist into air flow. The effect of the different key factors such the inlet Reynolds number, surface heat flux and water flux density on friction flow and heat transfer characteristics are examined. Experiments were performed in five cases using air as well as air/water mist two phase flow as working coolant for range of water flux density (j = 23.39 - 111.68 kg m-2 hr-1). The results obtained from the related experimental work revealed that the presence of water mist leads to a significant increase in heat transfer over the use of air coolant alone. The Nusselt numbers are respectively 1%, 19.7%, 90.2% and 134% higher than those in single phase - cooling for all cases of water flux density respectively. It was also found that the water flux density has little influence on friction factor. When the surface heat flux is fixed, the heat transfer enhancement factor increases with the increasing of water flux density.
The device for monitoring the LED display high-voltage insulators state
Authors: Balobanov R N , Zaripov D K , Akhmadeev A A
Published: June 2019

The article discusses the possibility of using devices for monitoring the state of highvoltage insulators with LED indication, mounted on insulating structures of high-voltage lines and substations. The scheme of the device is given and its principle of operation is described. The feasibility of indicating the early stage of the an insulation defect development in a laboratory and full-scale experiments on real power system facilities using devices with LED indication are shown. A new method of insulation control using the developed device will allow, when visually inspecting an overhead line, to additionally provide information about the change in the electric field and the appearance of discharges in the insulation. In addition to the early warning of the birth of a defect, this information will be useful for routine maintenance (cleaning) of insulators.
On the forecasting of trends of specific mixed loads of electric consumers of microdistricts and cities change in the conditions of inadequate data
Authors: Gasho E G , Guzhov S V , Krolin A A
Published: June 2019

The paper gives a brief analysis of modern methods of analysis, confirmation and prediction of specific mixed loads of electric consumers in housing estates and cities and formulates the main problems afflicting the reorganization of the industry, taking into account the requirements of digitalization of the economy. In order to identify the advantages and disadvantages of various solutions for optimizing the compilation of energy balances, a mathematical model is constructed, which allows analyzing the needs of microdistricts and cities in electrical energy and realizes the forecast of the development of urban energy systems in different socio-economic and climatic conditions.
Methodology of GHG emissions assessment caused at the construction of energy facilities. Case study: Hydropower
Authors: Avilova I P , Naumov A E , Krutilova M O
Published: June 2019

As energy is the main ‘fuel’ for social and economic development, and since energy-related activities have significant environmental impacts, it is important to lower emissions and stabilize atmospheric CO2 levels to avoid the worst predicted effects of climate change. Reducing energy consumption and costs is becoming central to planning, construction, and use of energy construction facilities from an environmental and economic point of view. Each energy source has advantages and disadvantages referred to: operating costs, environmental impact, and other factors. Each generation method produces some greenhouse gases (GHG) in varying quantities through construction, operation, and decommissioning. Some generation methods like coal fired plants release the majority of GHGs during operation. Others, such as wind power and hydro power release the majority of emissions during construction and decommissioning. Normalizing the lifecycle emissions with electrical generation allows a fair comparison of different generation methods on a per gigawatt-hour basis.
Determination of tensile strength of brittle materials by bending thin discs on the annular support
Authors: Goltsev V Y , Gribov N A
Published: June 2019

It is proposed to use the test of bending small thin disk specimens simply supported along the contour, to determine the resistance of material to tensile strain. The results of computer analysis of stress-strain state and test a thin disk specimens made of brittle materials are cast iron and graphite as a possible model, and directly samples made by electric pulse methods are presented. It is shown the effect of size of specimens on the resistance to their destruction and different character of deformation and destruction of cast iron and graphite samples. The possibility of application of thin disc samples for the determination the resistance to tensile strain of the composite ceramics based on SiAlON with various additives Y2O3, SiC, and TiN is confirmed.
Processing of mineral raw materials and production wastes by combustion under atmospheric conditions
Authors: Loryan V E , Kachin A R , Khomenko N Yu
Published: June 2019

The work considers the regularities of SHS of ferrotitanium, ferrochromium and synthetic mica-based fluorophlogopite. The powder mixture of minerals (silica sand, Karelian shungite, ilmenite, chromium concentrate from Shorzha) and secondary raw materials (recirculated cryolite) with metal reducing agents and KClO4 energy additive were used for the synthesis. The regularities of the initial mixture combustion under atmospheric conditions, the synthesized product composition and structure were investigated. Low-carbon ferrochromium with carbon content of 0.2%, ferrotitanium of the composition close to that of the industrial FeTi30 and synthetic mica-fluorophlogopite were synthesized. The synthesis of porous and molten-cast materials based on fluorophlogopite is shown to be possible. The composite material of K(Na)Mg3AlSi3O10Fe2-MgAl2O4-SiC was synthesized.
Features of the synthesis and consolidation of MeIVB2– (MeIV, Mo)Si2 ceramic powder for high-temperature applications
Authors: Pogozhev Yu S , Lemesheva M V , Potanin A Yu , Vershinnikov V I , Levashov E A
Published: June 2019

ZrB2–ZrSi2–MoSi2 and HfB2–HfSi2–MoSi2 composite ceramic powders were obtained by magnesiothermic SHS. The synthesized powders were consolidated by hot pressing in the temperature range of 1200-1250°C at 30 MPa. The structure and phase composition of the powders and compact ceramics were studied by X-ray powder diffraction analysis and scanning electron microscopy. ZrB2/HfB2, ZrSi2/HfSi2, ZrSi, and MoSi2 were the key phases of the ceramic powders and sintered ceramics. The average grain size of the powders after grinding was 6–8 μm. Saturation of the ZrSi phase with silicon and increased ZrSi2 content were observed during hot pressing. The dense ceramics had a residual porosity of 1.1–7.4%, which was largely dependent on the contents of silicides in SHS powders.
Simulation of spatial ordering of powder mixture particles when packed in square matrices using an example of monodisperse balls
Authors: Ponomarev M A , Loryan V E
Published: June 2019

The peculiarities of self-ordering of large particles of powder mixture components with layer-by-layer pressing of long billets used in material production by the method of self-propagating high-temperature synthesis (SHS) are studied using the example of structure formation at compaction of thin layers of a model system of monodisperse calibrated solid balls (1 mm in diameter). In unilateral axial compaction, the case of packing of thin layers of balls (containing 1–5 monolayers) in a square matrix (with a ratio of the transverse dimension of the matrix to the diameter of the ball ∼14) is considered at low pressures that do not cause significant deformation of the balls. In the disperse system under study, a structural ordering of the particles occurs with a characteristic stepped view of the curve of the compact height dependence on the number of balls in the initial charge of balls. With an increase in the number of balls in the charge, the density of thin layers changes periodically during the compaction. In the compacts, fragments of structures in which the particles are arranged orderly like regular packing of ideal balls appear. The square shape of the matrix provides the formation of fragments of rhombohedral and cubic packing. The influence of nonuniform distribution of the initial charge of balls inside the matrix on the structuring of thin layers during compaction is considered.
Electroconductivity of Al2O3/graphene nanocomposite processed by SPS technique
Authors: Sanchez-Bolinchez A , Klyatskina E , Segovia-Lopez F , Zholnin A G , Stolyarov V V
Published: June 2019

Electrical conductivity (σ), relative dielectric permittivity (εr) and dissipation factor (D) measured in graphene-alumina composites. Samples obtained by plasma spark sintering (SPS) from a mixture of raw powders: δ-alumina (36 nm average particle size) and graphene flakes (3 nm thickness and 2–3 μm length). Graphene content in samples was 0, 1 and 2% by weight. The study carried out for frequencies from 50 Hz to 100 kHz. Both c and εr were higher for Al2O3–2% graphene: up to 90 μS/m and 19 respectively; while alumina with 1% graphene showed similar values to the pure alumina samples: 50 μS/m to electrical conductivity and 16 to relative permittivity. The dissipation factor was similar in the three materials tested. D increased with the frequency, reaching high values (0.7) at 100 kHz. Composites with 1 and 2% graphene content showed a dissimilar dielectric behavior with the frequency. Alumina reflected a classical behavior of the permittivity dependence with the frequency. Graphene composites also show the same behavior at frequencies above 100 Hz. Below this frequency, the presence of graphene increases the relative permittivity to exceed that from pure alumina. The graphene content leads to rise of relative permittivity, which means easier polarizability.
Titanium carbide based metal-ceramic material with porous layered structure
Authors: Shustov V S
Published: June 2019

The method of obtaining a porous material with a layered structure is considered. This method makes it possible to create a finely porous layer on a highly porous base. The method was used to obtain a material based on titanium carbide powders. In the structure of flat samples of such material there were areas with different characteristics of porosity, such as volume and pore size. Creating a layered (or gradient) structure allows to increase the efficiency of membrane filters based on such material. The characteristics of the porous structure are determined. Filters based on titanium carbide powders were synthesized, the isotropic porous structure of which has the following characteristics: filtration fineness is about 460 nm with a total porosity of 39%, gas permeability of 3.3·10−19 kg/(m2·Pa·s) at a pressure drop of 0.05 MPa. Filters with a gradient structure had a filtration fineness of 320 nm and a gas permeability of 2.4·10−19 kg/(m2·Pa·s) at a pressure drop of 0.05 MPa.
2D MoS2 nanopores: ionic current blockade height for clustering DNA events
Authors: Diaz Carral Angel , Shekar Sarap Chandra , Liu Ke , Radenovic Aleksandra , Fyta Maria
Published: June 2019

2D nanopores can be used to electrophoretically drive DNA molecules, which can in turn be identified through measurable electronic current blockades. In this work, we use experimental data from molybdenum disulfide nanopores threading DNA nucleotides and propose a methodological approach to interpret DNA events. Specifically, the experimental ionic traces are used to train an unsupervised machine learning model for identifying distinct molecular events through the 2D nanopore. For the first time, we propose a clustering of experimental 2D nanopore data based on the ionic current blockade height and unrelated to the traditional dwell time for each DNA event. Within this approach, the blockade level information is implicitly included in the feature space analysis and does not need to be treated explicitly. We could show the higher efficiency of the blockade height over the traditional dwell time also in coping with sparse nanopore data sets. Our approach allows for a deep insight into characteristic molecular features in 2D nanopores and provides a feedback mechanism to tune these materials and interpret the measured signals. It has, thus, a high impact on the efficiency of 2D nanopore-based DNA sequencers.
Engineering the interface chemistry for scandium electron contacts in WSe2 transistors and diodes
Authors: Smyth Christopher M , Walsh Lee A , Bolshakov Pavel , Catalano Massimo , Schmidt Michael , Sheehan Brendan , Addou Rafik , Wang Luhua , Kim Jiyoung , Kim Moon J , Young Chadwin D , Hinkle Christopher L , Wallace Robert M
Published: June 2019

Sc has been employed as an electron contact to a number of two-dimensional (2D) materials (e.g. MoS2, black phosphorous) and has enabled, at times, the lowest electron contact resistance. However, the extremely reactive nature of Sc leads to stringent processing requirements and metastable device performance with no true understanding of how to achieve consistent, high-performance Sc contacts. In this work, WSe2 transistors with impressive subthreshold slope (109 mV dec−1) and I
ON/I
OFF (106) are demonstrated without post-metallization processing by depositing Sc contacts in ultra-high vacuum (UHV) at room temperature (RT). The lowest electron Schottky barrier height (SBH) is achieved by mildly oxidizing the WSe2
in situ before metallization, which minimizes subsequent reactions between Sc and WSe2. Post metallization anneals in reducing environments (UHV, forming gas) degrade the I
ON/I
OFF by ~103 and increase the subthreshold slope by a factor of 10. X-ray photoelectron spectroscopy indicates the anneals increase the electron SBH by 0.4–0.5 eV and correspondingly convert 100% of the deposited Sc contacts to intermetallic or scandium oxide. Raman spectroscopy and scanning transmission electron microscopy highlight the highly exothermic reactions between Sc and WSe2, which consume at least one layer RT and at least three layers after the 400 °C anneals. The observed layer consumption necessitates multiple sacrificial WSe2 layers during fabrication. Scanning tunneling microscopy/spectroscopy elucidate the enhanced local density of states below the WSe2 Fermi level around individual Sc atoms in the WSe2 lattice, which directly connects the scandium selenide intermetallic with the unexpectedly large electron SBH. The interface chemistry and structural properties are correlated with Sc–WSe2 transistor and diode performance. The recommended combination of processing conditions and steps is provided to facilitate consistent Sc contacts to WSe2.
Animal Ethics and Behavioral Science: An Overdue Discussion
Authors: Webb Christine E , Woodford Peter , Huchard Elise
Published: June 2019

Animal ethics—the field of philosophy concerned with the moral status of animals—is experiencing a momentum unprecedented in its history. Surprisingly, animal behavior science remains on the sidelines, despite producing critical evidence on which many arguments in animal ethics rest. In the present article, we explore the origins of the divide between animal behavior science and animal ethics before considering whether behavioral scientists should concern themselves with it. We finally envision tangible steps that could be taken to bridge the gap, encouraging scientists to be aware of, and to more actively engage with, an ethical revolution that is partly fueled by the evidence they generate.
A Life-Course Analysis of Engagement in Violent Extremist Groups
Authors: Carlsson Christoffer , Rostami Amir , Mondani Hernan , Sturup Joakim , Sarnecki Jerzy , Edling Christofer
Published: June 2019

In this exploratory study, individuals’ processes of engagement in violent extremist groups are analysed by drawing from criminological life-course theory and narrative-based understandings of crime. Based on interviews with individuals who have participated in violent extremism, it is suggested that the process of engagement consists of three steps: (1) a weakening of informal social controls, followed by (2) an interaction with individuals in proximity to the group and (3) a stage of meaning-making in relation to the group and one’s identity, resulting in an individual’s willingness and capacity to engaging in the group’s activities, including violence. In future theorizing about processes of engagement in violent extremism, the meanings of age, and the life-course stages of late adolescence and emerging adulthood in particular, should be given analytic attention.