East-west Axis Research Articles

Hydrochemical Characteristics and Genesis of Sand–Gravel Brine Deposits in the Mahai Basin of the Northern Qinghai–Tibetan Plateau

The sand–gravel brine deposit in the Mahai Basin is a newly discovered large-scale potassium–bearing brine deposit. The potassium–bearing brine is primarily found at depths exceeding 150 m within the porous alluvial and fluvial sand–gravel reservoir of the Middle to Lower Pleistocene. This deposit is characterized by a relatively shallow water table, moderate–to–strong aquifer productivity, high salinity, and a KCl content that meets the conditions for exploitation, with the advantage of reduced salt crystallization during well mining, making it a potential reserve base for potash development. A geochemical analysis of the sand–gravel brine revealed consistent trends for the major ions K+, Na+, Mg2+, Cl−, and SO42− along the east–west axis of the alluvial fan, while Ca2+ showed an opposite trend compared to Mg2+. Along the exploration lines from north to south, the concentrations of the main ions gradually increase. The brine is enriched in Na+ and Cl− ions, while SO42− and HCO3− are depleted. In the K+-Na+-Mg2+/Cl−-H2O (25 °C) quaternary phase diagram, the brine falls within the halite stability field, with the hydrochemical type classified as chloride type. The brine coefficient characteristics indicate a multi-source origin involving residual evaporation, salt rock leaching, and metamorphic sedimentary brine. Comparison studies of the ionic composition and isotopic signatures (δD, δ18O, δ37Cl, and δ7Li) of deep sand–gravel brines in the study area with interstitial and confined brines in the southern depression suggest similar geochemical characteristics between them. The genetic analysis of the deposit proposes that during the basin tectonic evolution, the potassium-rich interstitial and confined brines originally located in the southern depression of the Mahai Basin were displaced under compressional forces and migrated northward as the depositional center shifted, eventually backfilling into the loose alluvial and fluvial sand and gravel reservoirs at the front of the Saishiteng Mountains, forming the deep sand–gravel brine deposits in the foreland.

Characterization of Water Bodies through Hydro-Physical Indices and Anthropogenic Effects in the Eastern Northeast of Brazil

Brazil, despite possessing the largest renewable freshwater reserves in the world (8.65 trillion m3 annually), faces growing challenges in water management due to increasing demand. Agriculture, responsible for 68.4% of water consumption, is one of the main drivers of this demand, especially in the São Francisco River Basin, where irrigation accounts for 81% of total water withdrawals. Water bodies play a crucial role in sustaining ecosystems and supporting life, particularly along the East-West axis of Alagoas, a water-rich region in the ENEB. This study aimed to map and quantify the spatiotemporal variations of water bodies in the ENEB region and assess the impacts of human activities using MODIS satellite data, applying hydrological indices such as NDWI, MNDWI, and AWEI. Between 2003 and 2022, significant variations in the extent of water bodies were observed, with reductions of up to 100 km2 during dry periods and expansions of up to 300 km2 during wet seasons compared to dry periods. AWEI and MNDWI proved to be the most effective indices for detecting water bodies with MODIS data, providing accurate insights into water dynamics. Additionally, the MapBiomas Rios dataset, despite being resampled from a 30 m to a 500 m resolution, offered the most accurate representation of water bodies due to its methodology for data acquisition. Changes in albedo and surface temperature were also detected, highlighting the influence of climate change on the region’s water resources. These findings are crucial for guiding the sustainable management of water resources, not only in Alagoas but also in other regions of Brazil and similar semi-arid areas around the world. The study demonstrates the hydrological variability in the state of Alagoas, indicating the need for adaptive strategies to mitigate the impacts of climate change and anthropogenic pressures, supporting the need for informed decision-making in water resource management at both local and national levels.

Spatial and Temporal Variations in the Coupled Relationship between Ecosystem Services and Human Well-Being in Gansu Province Counties and the Factors Affecting Them

Investigating the interplay between ecosystem services and human well-being is crucial for enhancing ecological conservation and achieving a superior quality of development. This research examined the spatial–temporal disparities in ecosystem services and human well-being across 87 counties in Gansu Province using the coupling coordination degree model and geographically weighted regression analysis. The key findings include the following: (1) Over two decades, from 2000 to 2020, ecosystem services in Gansu Province witnessed a financial appreciation of approximately CNY 29.32 billion. The distribution displayed a notable trend, with higher values in the southeastern counties, particularly in Gannan and Longnan, whereas lower values prevailed in the Hexi area. (2) The well-being of the populace experienced a substantial enhancement, registering a 75% increase during the same period, characterized by higher well-being indices in the north, especially in Hexi, and the lowest indices in Gannan and the Linxia sector of Longzhong. (3) The coupling coordination degree between ecosystem services and human well-being escalated from 0.412 to 0.587, transitioning from moderate dysfunction to moderate coordination over the two decades. Regions such as Hexi and Gannan recorded a moderate discordance in their coupling coordination, whereas regions including Longzhong, Longnan, and Longdong demonstrated a more stable, basic coordination. (4) Influences on the coupling coordination degree between county ecosystem services and human well-being displayed significant spatial variability, often aligned along distinct geographic bands. Economic and natural foundations were predominantly aligned southeast to northwest, while investment and urbanization levels were more prominent from west to east, and industrialization levels were distributed along an east–west axis.

Comprehensive performance analysis of CST-PV system based on spectral beam splitting film

Abstract In this paper, a novel linear Fresnel concentrator (LFC) with a rotating platform was constructed, and a novel concentrated solar thermal and photovoltaic (CST-PV) hybrid system utilizing spectral beam splitting was established on the LFC. A spectral beam-splitting film (SBSF) was coated on the PV cell’s inner glass wall, replacing the LFC’s primary reflector. The SBSF can transmit the solar spectrum of 300-1100 nm to the photovoltaic (PV) cells and reflect the remaining solar wavelengths to the absorber to generate heat. The LFC’s cosine efficiency and end efficiency after azimuthal compensation by a rotating platform were calculated through theoretical analysis. The effects of temperature on the efficiency of PV and linear Fresnel solar systems were studied through experimental and numerical simulations. The comprehensive utilization efficiency evaluation method was established. The results show that the LFC’s end efficiency and cosine efficiency in this paper, after azimuthal compensation, increased by 31.7% and 33.7%, respectively, compared with the east-west and north-south axis placement. The comprehensive utilization efficiency of the CST-PV system based on SBS is 61.58%, which increased by 13.47% compared to that of the single fixed PV system.

Statistical analysis of regional STEC gradient trends for midlatitude ionosphere

In this study, the gradients of Total Electron Content (TEC) for a midlatitude region are estimated and grouped with respect to the distance between neighboring stations, time periods within a day, and satellite directions. Annual medians of these gradients for quiet days are computed as templates. The metric distances (L2N) and Symmetric Kullback-Leibler Distances (SKLD) are obtained between the templates and the daily gradient series. The grouped histograms are fitted to the prospective Probability Density Functions (PDF). The method is applied to the Slant Total Electron Content (STEC) estimates from the Turkish National Permanent GPS Network (TNPGN-Active) for 2015. The highest gradients are observed in the east-west axis with a maximum of 25 mm/km during a geomagnetic storm. The maximum differences from the gradient templates occur for neighboring stations within 100–130 km distance away from each other, during night hours, and for regions bordering the Black Sea and the Mediterranean in the northeast and southeast of Turkey. The empirical PDFs of the station-pair gradients are predominantly Weibull-distributed. The mean values of Weibull PDFs in all station groups are between 1.2 and 1.8 mm/km, with an increase during noon and afternoon hours. The standard deviations of the gradient PDFs generally increase during night hours. The algorithm will form a basis for quantifying the stochastic variations of the spatial rate of change of TEC trends in midlatitude regions, thus supplementing reliable and accurate regional monitoring of ionospheric variability.

Exploring aspects of Neanderthal mobility in the Mani Peninsula: Evidence from Lithic Raw Material procurement and management at Kalamakia Cave, Greece

The Kalamakia cave located on the western Mani Peninsula, southern Greece is a Middle Palaeolithic site dated between ∼100,000 and >39,000 years BP. The aim of this paper is to provide insights into the Neanderthal groups’ mobility by addressing the lithic raw material procurement and management, with reference to the Kalamakia cave assemblage. The methodology included field survey and laboratory analyses, encompassing macroscopic, petrographic, and geochemical ones, for the location and identification of the sources of used lithic raw materials. Local, semi-local and allochthonous lithic raw materials were used by the Neanderthals at the Kalamakia cave to manufacture tools. The presence of various lithic raw materials used at the cave suggests diverse mobility strategies. The semi-local black/grey chert, followed by the allochthonous andesite was mostly used. Andesite transported across an east–west axis presents a long-term stability, both in terms of percentages and the different artefact types transported in both Unit III and IV of the cave. The significant quantities of andesite in the cave’s assemblage suggest non-random mobility, possibly linked to the exploitation of different ecological environments available in the region. The north-western part of the peninsula saw additional exploitation by groups moving along the coastal north–south corridor. However, cherts transported along this axis occurred occasionally, and their quantities were notably smaller in comparison to andesite. The strategic location of the cave close to the intersection of two natural movement routes, may have played a key role in the circulation of Palaeolithic inhabitants, facilitating movements along east–west and north–south axes.

Două planuri necunoscute ale Craiovei din a doua jumătate a secolului al XVIII-lea – jumătatea secolului al XIX-lea

In this study, we publish two plans of Craiova, discovered at the Military-Historical Archive of Moscow: a plan made during the occupation of Wallachia in 1771–1774 and another made either during the occupation after the 1848 revolution (1848–1851) or during the first year of the Crimean War (August 1853 – April 1854). Both plans support the idea that the town underwent organic development, which took into account the local landforms and the way man intervened. Its location in the Jiu Valley played a significant role in the emergence and evolution of this centre, as the course of the river was accompanied by an important road, Craiova being at the intersection with other major traffic routes of this region of the country. The valleys bordering the urban core had the role of delimiting the original inhabited area and the position of the “Bănia” area, with the church of St. Dumitru, as a strategic area and centre of power, on the edge of the coast overlooking the valley towards the west, is evident. Separately, across another small valley, the heart of the town developed, the market, the area with the best economic outlook, not coincidentally located at the crossroads of the main east-west and south-north axes. The medieval town evolved around these two cores, but development and population growth meant the valleys bordering it were overtaken by the 18th century. How the streets converged in the town underlines the idea of gradual growth, and the concentration of roads around the focal point that was the town market marked the layout of Craiova. Human intervention up to the 1830s and 1840s took place not only through the building of dwelling houses, shops and workshops but also through the construction of major landmarks represented by churches and monasteries, around which the neighbourhood (mahala) gravitated. Once the process of modernization began, the anthropic footprint became even more important through the extensive building actions initiated after the Organic Regulation, some of which are visible in the second plan studied. Unfortunately, we could not identify the plan’s authors among the Russian army surveyors of those periods. The two cartographic documents contribute to a better knowledge of Craiova in the second half of the 18th century and the first half of the following century, adding to the already known plans (the Austrian plan of 1790 and the Romanian one of 1845).

A preliminary study of genetic diversity in populations of Montrichardia Crueg. (Araceae) estimated with ISSR molecular markers

AbstractThe two species of Montrichardia (Araceae) are perennial herbs of great ecological, economic, and ethnobotanical importance that form populations by clonal growth and sexual reproduction. Here, genetic diversity was studied within a drainage system distant from Amazonia. Five populations were sampled from the Rio Parnaíba Delta (northeast Brazil) and two outside it. The eight ISSR primers selected generated 342 marker bands. The non‐Delta populations (M. arborescens) were grouped together by cluster analysis and Bayesian simulation but the Delta populations (M. linifera) were only grouped weakly. Ordination and Bayesian simulation grouped populations into three pairs along an east–west axis. All population pairs were significantly different (pairwise PhiPT, p ≤ 0.001). Between‐population variance (AMOVA, 39.9% variance, p < 0.001) was much greater than between‐species (12.2%, p < 0.034), but within‐population variance was greatest (48.0%). Within the Delta, geographical distance between populations did not predict genetic similarity, but relative within‐population diversity appears to be influenced by habitat differences. There is genetic evidence, but relatively weak, for recognizing the Delta populations as M. linifera and the non‐Delta ones as M. arborescens; Paulino Neves (Maranhão) appears to be the easternmost record for this species. The strong between‐population differences previously reported for M. linifera are corroborated.

Geopolitical Positioning of a Small State: Serbia in the Shadow of Yugoslavia’s ‘Third Way’

This article examines Serbia’s positioning in the East-West axis during the post-Cold War era. This is a specific example of the ‘third way’ in twenty-first century geopolitical behaviour. The small country remains non-aligned within the existing alliances of the East and the West, trying to find a balance between their influence and remaining faithful to its national interests. Although with far more modest resources, the situation of the Serbian state is reminiscent of the fate of Yugoslavia, which was among the initiators of the Non-Aligned Movement (NAM). Relying on substantial empirical evidence, this article claims that being a small state is not an insurmountable obstacle to pursuing an assertive foreign policy, albeit at the cost of complicated relations with neighbouring countries and those geopolitical forces dominating the current world order. Summarising the Serbian experience in ‘third way’ geopolitics, a model of multiple asymmetries in interrelations between the small state and great powers is elaborated.

Ансамбль Императорского путевого дворца на «Государевой дороге» в Торжке

Torzhok is rightfully considered among the most ancient cities in the Tver region, since the settlement on the territory of the Novotorzhsky Kremlin appeared no later than the turn of the 10th century. There, in the Middle Ages, over the years the administrative center of the city was formed and existed until the second half of the 18th century. The landmark in its history were the urban planning reforms initiated by Catherine II. Having given instructions to adjust the layout of Torzhok taking into account other, “regular” principles of organizing the urban environment, the Empress ordered her residence in this city to be located on the opposite, not the “Kremlin”`s, left bank of the Tvertsa. As a result, in the 1770s, the beginning of the formation of a new square — the Palace Square — was laid here. Almost simultaneously with the palace ensemble, the construction of several more administrative complexes began on this square, including offices, the houses of the mayor and treasurer, the post office, as well as various “services” necessary for their full existence. The “regular” square, stretched along the east-west axis, was organically linked to the route of the "Tsar's Road" so that the representatives of the royal family could get to their travel residence without interference. At the same time, the Imperial Palace served not only as the main city-forming accent of the square, but also as the dominant one in this part of the Left Bank, since the main building of the complex was placed on the high bank of the Tvertsa. However, the palace function did not remain decisive for this ensemble for long. After several decades, it was significantly adjusted, and by the middle of the 19th century the palace was a dilapidated architectural complex. Only the transferring of it to the department of education allowed to breathe new life into the ensemble created in the second half of the 18th century.

Masters of Places: Music and Territory in Makadade (Atauro, East Timor)

On the island of Atauro, certain musical forms are deeply connected to space, which the Adadi conceive of in six primary directions. Each direction is governed by opun (ʻownersʼ, ʻmastersʼ). Specific melodies, rhythms, vocal calls, and instruments, distinguish neighboring territorial zones. This musical polarisation, evident in both discourse and musical content, highlights the importance of the east-west axis, which structures the Adadi territory. Each direction is associated with distinct values, expressed through sound, particularly via complementary instruments that correspond to the eastern and western mountain ranges. The music is part of a system of spatial oppositions relating to place, revealing a hierarchical representation of space and the dynamics of territorial occupation by rival groups.

SOLVING FIRST SCIENTIFIC PROBLEMS ON PRELIMINARY ADJUSTMENT OF THE ANTENNA OF THE ROT-54/2.6 RADIO-OPTICAL TELESCOPE

The ROT-54/2.6 radio-optical telescope was built in the Aragats Scientific Center by the institution headed by Professor Paris Herouni in 1980-1987 and still has the world's largest double-reflector spherical antenna. After working for more than three decades, it was mothballed in 2012, since there was a physical impact on various structures of the radio-optical telescope due to natural and artificial phenomena. In connection with the fact that the ROT-54/2.6 radio-optical telescope has remained in the mentioned state for a long time, some antenna parameters may have changed compared to the initial parameters. In particular, in 2015, one of the support brackets of the East-West axis of the antenna structure failed and its axis was welded by the decision of the autorities of the National Institute of Metrology without carrying out research and repairs at that time, just to keep the axis stationary. For this reason, at present, the small reflector of the telescope can move only due to rotating around one axis. Therefore, in order to reactivate and reboot the radio optical telescope, it is necessary to know with high accuracy the shift of the physical, ge-ometric and radio engineering parameters of the antenna, and thus estimate the amount of work on the reboot.

Natural clines and human management impact the genetic structure of Algerian honey bee populations

BackgroundThe Algerian honey bee population is composed of two described subspecies A. m. intermissa and A. m. sahariensis, of which little is known regarding population genomics, both in terms of genetic differentiation and of possible contamination by exogenous stock. Moreover, the phenotypic differences between the two subspecies are expected to translate into genetic differences and possible adaptation to heat and drought in A. m. sahariensis. To shed light on the structure of this population and to integrate these two subspecies in the growing dataset of available haploid drone sequences, we performed whole-genome sequencing of 151 haploid drones.ResultsIntegrated analysis of our drone sequences with a similar dataset of European reference populations did not detect any significant admixture in the Algerian honey bees. Interestingly, most of the genetic variation was not found between the A. m. intermissa and A. m. sahariensis subspecies; instead, two main genetic clusters were found along an East–West axis. We found that the correlation between genetic and geographic distances was higher in the Western cluster and that close-family relationships were mostly detected in the Eastern cluster, sometimes at long distances. In addition, we selected a panel of 96 ancestry-informative markers to decide whether a sampled bee is Algerian or not, and tested this panel in simulated cases of admixture.ConclusionsThe differences between the two main genetic clusters suggest differential breeding management between eastern and western Algeria, with greater exchange of genetic material over long distances in the east. The lack of detected admixture events suggests that, unlike what is seen in many places worldwide, imports of queens from foreign countries do not seem to have occurred on a large scale in Algeria, a finding that is relevant for conservation purposes. In addition, the proposed panel of 96 markers was found effective to distinguish Algerian from European honey bees. Therefore, we conclude that applying this approach to other taxa is promising, in particular when genetic differentiation is difficult to capture.

Neotraditionalism and Innovations in Kazakh Instruments and Music-Making

In the XX and XXI centuries, Kazakh music went through three waves of innovations: first, after centuries of solo-only performance, ensembles and orchestras appeared in the first decades of the Soviet period. Then, ethnographic, iconographic, and archaeological research brought back to life lost or nearly-forgotten instruments in 1970-80s, and in the 2000s new types of ensembles and neo-folk instruments appeared under global influences. All these changes were driven by two opposite tendencies: intensive cross-cultural interaction (primarily on the West-East axis) met the growing interest to the nation’s past. This neotraditional mindset influences, on the one hand, to music instrument-making, on the other hand, to performance practice. In the first wave, the need for creating the orchestra of Kazakh folk instruments, declared by Akhmet Zhubanov, caused the foundation of the workshop where standardized dombra (plucked lute chordophone) and qobyz (bowed lute chordophone) were created together with their modernized cousins (prima, alto and bass versions). During the second wave, such prominent scholars as Bolat Sarybayev turned to a restoration of the lost instruments (sherter, zhetygen, saz syrnai, percussionand so on) that were later included in orchestras and ensembles and even institutionalized within the conservatoire’s classes. The third wave is strongly associated with various kinds of popular music. Some ensembles (as Turan and Hassak) moved toward the World music style, others (as Aldaspan) experimented in electronic and rock directions. So, it is obvious that all three waves are interconnected. Unification and experiments with materials in the early Soviet period, as well as the creation of special workshops and laboratories for folk music, have created a systematic cycle of research and reconstructions.

The impact of aspect ratio of buildings implementing Horizontal light pipe and shading systems on daylight performance

ABSTRACT Deep-plan buildings limit daylight use in spaces far from the building perimeter, leading to uneven daylight distribution. Integrating a Horizontal Light Pipe (HLP) as an optical daylighting system, reflective light shelves, and blinds as shading systems can reduce excessive daylight levels at the perimeter area of a building and improve daylight uniformity. Earlier investigations of HLP daylight performance concentrated on fixed building geometries, but few studies focused on the building aspect ratio, one of the design variables of building geometry that greatly influences daylight performance. This study aims to investigate the impact of the aspect ratio of buildings implementing HLP and shading systems on daylight performance. The research method was experimental, using IES-VE simulation as a tool. The daylight factor (DF), uniformity daylight factor (UDF), and useful daylight illuminance (UDI) of various aspect ratios and depths of office buildings implementing HLP and shading systems were analyzed. The results show that increasing the building aspect ratio from 1:1 to 2.1:1 sequentially increased the average DF and UDF values by 18.47% and 17.2%, respectively. Improving the building aspect ratio from 1:1 to 2.1:1 along the east-west axis improved the UDI by 3%, whereas the north-south axis decreased it by 10.2%.

Wind-Induced Vibrations and Gust Response Factors of the Cabin–Cable–Tower System

A large-scale radio astronomical telescope is a typical complex coupled system, consisting of a feed cabin, cables, and supporting structures. The system is extremely sensitive to wind loads, especially the feed cabin, which has high requirements for vibration displacement during operation, and excessive vibration may affect normal operation. To investigate the wind-induced vibration characteristics of such coupled systems, this study takes the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) as an example to conduct research. First, a refined finite element model of FAST is established, and a dynamic analysis using simulated random wind loads is conducted. The influence of the cable boundary on the time–frequency domain responses of the feed cabin is particularly considered. Then, the gust response factor (GRF) for different structural components within the coupled system is calculated. Finally, the evolution law of the GRF under various wind speeds and directions is revealed by parametric analysis. The parameter analysis only considers the wind directions ranging from 0° to 60°, because FAST is a symmetric structure. The results indicate that obvious differences are observed in both the rotational and translational displacements of the feed cabin under northward wind, especially the results along the east–west axis. When the supporting towers are considered, there is no change in the power spectral density (PSD) of the feed cabin in the low-frequency range. However, in the high-frequency range, taking the supporting towers into account leads to an increase in PSD and a resonance near the first-order natural frequency of the supporting tower. The GRF based on the dynamic response exhibits substantial deviations compared to those obtained from design codes, highlighting the need for an independent analysis when determining GRF for such coupled systems.

Spatiotemporal Pattern of Carbon Compensation Potential and Network Association in Urban Agglomerations in the Yellow River Basin

The Yellow River Basin is an important energy base and economic belt in China, but its water resources are scarce, its ecology is fragile, and the task of achieving the goal of carbon peak and carbon neutrality is arduous. Carbon compensation potential can also be used to study the path to achieving carbon neutrality, which can clarify the potential of one region’s carbon sink surplus to be compensated to the other areas. Still, there needs to be more research on the carbon compensation potential of the Yellow River Basin. Therefore, this study calculated the carbon compensation potential using the β convergence test and parameter comparison method. With the help of spatial measurement tools such as GIS, GeoDa, Stata, and social network analysis methods, the spatiotemporal pattern and network structure of the carbon compensation potential in the Yellow River Basin were studied from the perspective of urban agglomeration. The results demonstrate the following: (1) The overall carbon compensation rate of the YRB showed a downward trend from 2005 to 2019, falling by 0.94, and the specific pattern was “high in the northwest and low in the southeast”. The spatial distribution is roughly spread along the east–west axis, and the distribution axis and the center of gravity keep shifting to the northwest. It also showed a weak divergence and a bifurcation trend. (2) The carbon compensation rate in the YRB passed the spatial correlation and β convergence tests, demonstrating the existence of spatial correlation and a “catch-up effect” among cities. (3) The overall distribution pattern of the carbon compensation potential in the YRB is a “low in the west and high in the east” pattern, and its value increased by 8.86% during the sampled period. (4) The network correlation of carbon compensation potential in the YRB has been significantly enhanced, with the downstream region being more connected than the upstream region. (5) The Shandong Peninsula Urban Agglomeration has the largest network center, followed by the Central Plains Urban Agglomeration, and the Ningxia along the Yellow River Urban Agglomeration has the fewest linked conduction paths. According to the research results, accurate and efficient planning and development suggestions are proposed for urban agglomeration in the Yellow River Basin.

Thermodynamic analysis and optimization of liquid air power plant integrated with parabolic trough solar collectors

ABSTRACT As to investigate the impact of parabolic trough collector optical characteristics on the comprehensive performance of solar-driven liquid-gas energy storage power plants, this study establishes a mathematical analysis model for a liquid-gas energy storage power plant with a parabolic trough collector. The effects of direct irradiance, collector tracking mode, and component configuration on collector efficiency, round-trip efficiency, and exergy efficiency are analyzed. The results show that when the direct irradiance exceeds 400 W/m2, the round-trip efficiency of the system decreases while the exergy efficiency increases. For every 100 W/m2 increase in irradiance, the round-trip efficiency decreases by 1.54%, and the exergy efficiency increases by 2.36%. The north-south axis tracking mode is superior to the east-west axis tracking mode and dual-axis tracking mode. The component configuration improves the collector efficiency and round-trip efficiency but decreases the thermal efficiency. In low irradiance conditions (direct irradiance less than or equal to 400 W/m2), the system performance is optimal when the collector optical efficiency is maintained at 74%. Under these conditions, the system achieves a maximum net energy output of 495.12 kW·s/kg, the exergy efficiency of 54.5%, and the round-trip efficiency of 18.96%. In high irradiance conditions (direct irradiance greater than 400 W/m2), a 10% increase in collector optical efficiency leads to a 1.94 kW·s/kg decrease in net energy output, a 3.14% decrease in exergy efficiency, and a 0.05% decrease in round-trip efficiency.

Magnetic Fabric and Paleomagnetic Analyses of the Zaghar and Tafresh Areas, Central Urumieh-Dokhtar Magmatic Arc, Iran

Magnetic fabric, paleomagnetic, and petrophysical studies were conducted on rocks in the Tafresh area of the central Urumieh-Dokhtar magmatic arc in Iran. The samples included Late Triassic dark gray sandstone, a mafic dyke, diorites, and a felsic dyke in the Zaghar region. Hydrothermal alteration in the Spid intrusion was investigated to understand the effects of alteration on magnetic fabric patterns. The AMS measurements support the theory that the Nayband Formation was constructed under a crustal extension regime. Magnetic susceptibility anisotropy in a microdioritic dyke indicates compression from the NNE-SSW, likely due to tectonic activity. AMS results from diorites in Zaghar suggest intrusions were emplaced in extensional spaces between the Tafresh and Chaghar thrust faults. The Spid intrusion’s magnetite is the primary carrier of magnetic susceptibility, but hydrothermal alteration has partly converted it into hematite, resulting in lower susceptibility and higher porosity in altered diorites. This process leads to a bimodal distribution of magnetic lineation trends. The Spid and Zaghar massifs underwent a northward tilt of about 30 degrees around an east-west axis following the Early Miocene. Post-Eocene rotations in the area are typically within ±20 degrees. This study demonstrates how magnetic properties can provide new insights into the evolution of tectono-magmatic processes and structural controls within a magmatic arc.

Metal and metallothionein concentrations in mesozooplankton from an oligotrophic offshore area in the eastern Mediterranean Sea (Cretan Passage/Levantine Sea)

Spatial variability of Cd, Cu, Cr, Ni, Zn, Fe, Mn, Pb and metallothionein (MT) concentrations were determined in mesozooplankton samples along the west-east axis of the Cretan Passage in the western Levantine Sea (Eastern Mediterranean). Metal and MT values from the present study are proposed as background levels, due to the lack of substantial anthropogenic activities in the area, where only maritime traffic and atmospheric deposition could be potential sources. Higher concentrations, of both metals and MTs, were recorded mainly at the western stations indicating higher metal bioavailability than in the eastern part. An inverse relationship of the metal zooplankton levels with zooplankton biomass, abundance and vital rates (production, respiration and ingestion rates), as well as salinity, was evident. We discuss the hypothesis that physical and biological characteristics of the marine environment, affecting growth dynamics of phytoplankton and zooplankton communities, may also act on metal uptake in oligotrophic marine systems.