The find of an exceptional set of notarial documents from Puente Genil, conserved in the Provincial Historical Archive of Cordoba and dated between 1566 and 1594, has allowed a deeper knowledge of ...the exploration of millstone quarries located around of this town during the second half of the sixteenth century. The features of the work are approached from a technical (types and location of the quarries, extraction systems of the stones, type of grinding stones obtained) and human (property of the quarries, workers organization, systems used for transport, territorial scope of use and economic cost of molars) point of view, deepening the understanding of this activity during one of the most intense periods of exploitation in its history.
The present study investigates for the first time a largely forgotten pyrotechnology for manufacturing artificial millstones for Persian windmills and querns from Islamic period Sistan, a region in ...southeastern Iran. The unusual characteristics of these materials result from melting a sand-clay mixture at high temperatures. A unique experimental and multianalytical method was developed to understand the heating-cooling regime for manufacturing artificial millstones and other technical details of their production. According to chemical and microstructural analyses, these materials were melted between 1150 °C and 1250 °C and kept there for a period of 14–20 h, to be subsequently cooled down by 10–50 °C/h. Our experimental results for reproducing the microstructure of these objects show that any other temperature regime would be unsuccessful for manufacturing a functional millstone for these huge windmills which are usually referred to as the first wind turbines in the history of technology.
В статье предлагается на обсуждение тематика переработки зерна и развитие мукомольного производства в городах Золотой Орды. Рассматривается потребность в результатах этого производства среди кочевого ...населения, путешествующих купцов, послов и миссионеров. Следы переработки зерна приводятся как на примере археологических исследований города Маджар и материалов, полученных при археологических работах в городе Азаке, так и на основании средневековые письменных источников.
ЛИТЕРАТУРАБабенко А.Н., Сергеев А.Ю. Археоботанические исследования городища Маджары // Поволжская археология. 2019. №4(30). С. 161–170 doi: 10.24852/pa2019.4.30.161.170Барбаро И. Путешествие в Тану Иосафата Барбаро, венецианского дворянина // Библиотека иностранных писателей о России. Т. 1. СПб.: Типография III отделения Собственной Е.И.В. Канцелярии, 1836. С. 5−66. C. 17Городцов В.А. Результаты археологических исследований на месте развалин города Маджар в 1907 году // Труды четырнадцатого археологического съезда в Чернигове, 1909 г. Т. III / Под ред. графини Уваровой. М., 1911. С. 162–208.Контарини A. Путешествие Амвросия Контарини посла светлейшей Венецианской республики к знаменитому персидскому государю Узун-Гассану, совершенное в 1473 году // Библиотека иностранных писателей о России. Т. 1. СПб.: Типография III отделения Собственной Е.И.В. Канцелярии, С. 91−92.Минаев А.В. Переработка зерна в Азаке в XIV в. // Археология Евразийских степей. 2018. № 4. C. 127−140.Недашковский Л.Ф. Хозяйство населения Золотой Орды // РA. 2009. №1 С. 91−98.Пигарев Е.М «К вопросу о земледелии на нижней Волге в золотоордынский период»// Астраханские краеведческие чтения. Вып. I. / Ред. А.А. Курапов. Астрахань: Сорокин Роман Васильевич, 2009. С. 62−65.Тизенгаузен В. Сборник материалов, относящихся к истории Золотой Орды. Т. I. Арабские источники. СПб, 1884. 588 с.Франческо Пеголотти. Руководство по торговли // Кавказ: европейские дневники XIII-XVIII веков. Вып. III. / сост. В. Аталиков. Нальчик. Из-во М. и В. Котляровых, 2010. С. 10−11.
The article proposes to discuss the issue of grain processing and the development of flour milling in the cities of the Golden Horde. Using the example of the archaeological research of the city of ...Madzhar and the materials obtained during the archaeological work in the city of Azak, as well as drawing on medieval sources, the need for this production among the nomadic population, traveling merchants, ambassadors and missionaries is also considered.
This work conducts a statistical study of the subauroral polarization stream (SAPS) feature in the North American sector using Millstone Hill incoherent scatter radar measurements from 1979 to 2019, ...which provides a comprehensive SAPS climatology using a significantly larger database of radar observations than was used in seminal earlier works. Key features of SAPS and associated electron density (Ne), ion temperature (Ti), and electron temperature (Te) are investigated using a superposed epoch analysis method. The characteristics of these parameters are investigated with respect to magnetic local time, season, geomagnetic activity, solar activity, and interplanetary magnetic field (IMF) orientation, respectively. The main results are as follows: (1) Conditions for SAPS are more favorable for dusk than near midnight, for winter compared to summer, for active geomagnetic periods compared to quiet time, for solar minimum compared to solar maximum, and for IMF conditions with negative By and negative Bz. (2) SAPS is usually associated with a midlatitude trough of 15–20% depletion in the background density. The SAPS‐related trough is more pronounced in the postmidnight sector and near the equinoxes. (3) Subauroral ion and electron temperatures exhibit a 3–8% (50–120 K) enhancement in SAPS regions, which tend to have higher percentage enhancement during geomagnetically active periods and at midnight. Ion temperature enhancements are more favored during low solar activity periods, while the electron temperature enhancement remains almost constant as a function of the solar cycle. (4) The electron thermal content, Te × Ne, in the SAPS associated region is strongly dependent on 1/Ne, with Te exhibiting a negative correlation with respect to Ne.
Key Points
Key features of North American SAPS and associated Ne, Ti, and Te were analyzed using four decade Millstone Hill IS radar measurements
North American SAPS climatology in terms of MLT, season, geomagnetic activity, solar activity, and IMF condition was comprehensively studied
Both ion and electron temperatures exhibit moderate enhancement around SAPS, with similar geomagnetic but different solar activity dependence
This paper reports the characteristics of the topside ionospheric O+ diffusive flux (ΦO+) during both geomagnetically quiet (0 ≤ Kp ≤ 2) and moderate (2 < Kp ≤ 4) times using incoherent scatter radar ...observations at Millstone Hill (42.6°N, 288.5°E) for solar minimum from 1970 to 2018. ΦO+ partially characterizes plasma mass exchange between the upper and lower part of the topside ionosphere through diffusion and sometimes serves as upper boundary conditions for ionosphere‐thermosphere models. The altitude where the flux sign changes (mainly during daytime) is termed the transition height and the time when the flux sign changes (mainly at dawn and dusk) is termed the transition time. At quiet times, the daytime transition height is ∼100 km above the F2 peak height (hmF2) in summer, and it is about 50 km above hmF2 in other seasons; the transition time is before 18 solar local time (SLT) in spring and winter, but after 18 SLT in summer and autumn. The daytime average upward ΦO+ above the transition height shows a significant seasonal variation with a minimum of 2.2×108cm−2s−1 in summer and a maximum of 3.7×108cm−2s−1 in autumn. Under geomagnetically moderate conditions, the transition height increases by ∼20 km in spring, winter, and autumn, but moves up by about 20–50 km in summer. The transition time occurs later by ∼1 hr in summer but ∼1 hr earlier in other seasons. The mean upward ΦO+ peaks in summer and minimizes in spring.
Plain Language Summary
The topside ionospheric O+ diffusive flux (ΦO+) is a part of the total plasma flux that is a critical parameter to characterize the plasma exchange between the upper and lower part of the topside ionosphere, but has been poorly known due to lack of direct measurements. Using long‐term incoherent scatter radar (ISR) data observed at Millstone Hill for nearly five decades, this study investigates ΦO+ variations as a function of the altitude above the F2 peak height (hmF2), local time, and season in both geomagnetically quiet and moderate times, and further explores the physical mechanism causing these variations. During quiet times, the summer daytime transition height where ΦO+ changes from downward to upward along magnetic field lines occurs at ∼hmF2+100 km. However, it is usually near hmF2+50 km in other seasons. In addition, the transition time when ΦO+ changes from upward to downward at a fixed height is earlier than 18 SLT in spring and winter, but later than 18 SLT in summer and autumn. We also found that an increase in geomagnetic activity decreases the vertical gradient of plasma density during the daytime in all seasons, resulting in a ∼20 km increase in the transition height and an earlier transition time near dusk in spring, autumn, and winter, but a larger transition height change of about 20–50 km and a later transition time in summer. The change in the seasonal variations of the upward ΦO+ results from the competition between the variations of plasma diffusive velocity and density when the geomagnetic activity increases, as well as the changes in plasma vertical density profiles.
Key Points
Topside ionospheric O+ diffusive flux (ΦO+) climatology at solar minimum is derived from incoherent scatter radar data at Millstone Hill
O+ diffusive flux has seasonal, local time, and altitude dependence
Geomagnetic activity changes the spatiotemporal variations of Φ(O+) by modulating the vertical gradient of the plasma density
Ion temperature data recorded by Millstone Hill incoherent scatter radar (42.61° N, 288.51° E) over four full solar cycles (from 1970 to 2018) are analyzed to depict its climatological behavior in ...the range of altitudes between 100 and 550 km. The ion temperature dependencies on altitude, local time, month of the year, and solar activity level are studied through a climatological analysis based on binning and boxplot representation of statistical values. Binned observations of ion temperature are compared with International Reference Ionosphere (IRI) modeled values (IRI-2016 version). This comparison reveals several shortcomings in the IRI modeling of the ion temperature at ionosphere altitudes, in particular for the altitudinal, diurnal, seasonal, and solar activity description. The main finding of this study is that the overall IRI overestimation of the ion temperature can be probably ascribed to the long-term ionosphere cooling. Moreover, the study suggests that the IRI ion temperature model needs to implement the seasonal and solar activity dependence, and introduce a more refined diurnal description to allow multiple diurnal maxima seen in observations. The IRI ion temperature anchor point at 430 km is investigated in more detail to show how also a better description of the altitude dependence is desirable for modeling purposes. Some hints and clues are finally given to improve the IRI ion temperature model.
A survey of millstone and grindstone production sites in the western Pennines of north-west England has identified 54 sites. Combining archival research with field survey, the production of millstone ...roughouts was identified at varying scales at each site, with evidence for the production of grindstones and edge runners apparent at several of the sites. Very few of these production sites have received attention from past researchers and some were previously unrecorded. The survey has enabled a detailed picture to be compiled of production methods, sales and transportation of roughouts from the medieval period to the early 20th century. Various case studies are used to illustrate the nature of this lost rural industry.
Ionospheric F‐region electron density is anomalously higher in the evening than during the daytime on many occasions in the summer in geomagnetic mid‐latitude regions. This unexpected ionospheric ...diurnal variation has been studied for several decades. The underlying processes have been suggested to be related to meridional winds, topside influx arising from sunset ionospheric collapse, and other factors. However, substantial controversies remain unresolved. Using a numerical model driven by the statistical topside O+ diffusive flux from the Millstone Hill incoherent scatter radar data, we provide new insight into the competing roles of topside diffusive flux, neutral winds, and electric fields in forming the evening density peak. Simulations indicate that while meridional winds, which turn equatorward before sunset, are essential to sustain the daytime ionization near dusk, the topside diffusive flux is critically important for the formation and timing of the summer evening density peak.
Plain Language Summary
The phenomenon of mid‐latitude summer nighttime anomalous ionospheric electron density enhancement (MSNA) has often been observed by both ground‐based and space‐based measurements. Previous observation and simulation studies suggested that the combined effects of neutral winds and geomagnetic field configuration are the drivers of the formation of MSNA. These results, particularly some modeling results, were obtained under some constraints and assumptions that have not been strictly validated either through critical observations or self‐consistent, first principle simulations of the coupled ionosphere‐thermosphere system. This study represents a major new advance in understanding an important controlling factor that has not been adequately addressed before. In this study, we evaluate the relative roles of topside diffusive flux, meridional winds, and electric fields over Millstone Hill, where MSNA‐like anomalies are very representative of mid‐latitudes. Using a self‐consistent coupled ionosphere‐thermosphere model, Thermosphere–Ionosphere−Electrodynamics General Circulation Model, driven by the statistical topside O+ diffusive flux from the Millstone Hill Incoherent Scatter Radar data, we found that topside O+ diffusion is critical for the formation and timing of the evening electron density peak, although it is also very clear that meridional winds, which turn equatorward before sunset, are essential for sustaining the daytime ionization near dusk. This new finding from the Millstone Hill observations may lead to an ultimate understanding of the more generic MSNA features in both the Northern and Southern Hemispheres.
Key Points
The ionospheric electron density summer evening anomaly at Millstone Hill is investigated using a joint observation and simulation analysis
Topside O+ diffusive flux is critical for anomaly formation and timing, while thermospheric winds act to preserve solar‐produced plasma
A much better understanding of the mid‐latitude summer night anomaly is achieved with observation‐informed topside specification
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