Dry Phase Research Articles

Construction of Energy Consumption Model in Asphalt Mixture Production Stage Based on Field Measurements

To better construct an energy consumption model for the asphalt mixture production stage, this study divides the production process into four phases: aggregate dust removal, aggregate drying, asphalt heating, and mixture blending. Utilizing measured data from various regions in Anhui Province, the model considers factors such as season, mixture type, and energy consumption type. The study quantitatively compares and analyzes the energy consumption results obtained from three calculation methods: the theoretical method, the quota method, and the energy consumption model method. The results indicate that the total energy consumption shares of the aggregate dust removal, aggregate drying, asphalt heating, and mixture blending phases are 4.23%, 69.50%, 17.75%, and 8.52%, respectively. The primary energy consumption during the asphalt mixture production stage is concentrated in the aggregate drying and asphalt heating phases. The energy consumption model based on on-site measurements effectively reflects the actual energy consumption levels during the asphalt mixture production stage. Moreover, the total energy consumption calculated by the three methods follows the order quota method > energy consumption model method > theoretical method. By constructing an energy consumption model based on measured data, it is possible to more accurately assess the energy usage during the asphalt mixture production process. This helps optimize production techniques, reduce energy consumption and carbon emissions, and provide a scientific basis for sustainable road construction.

The Efficiency of Polyester-Polysulfone Membranes, Coated with Crosslinked PVA Layers, in the Water Desalination by Pervaporation.

Composite polymer membranes were obtained using the so-called dry phase inversion and were used for desalination of diluted saline water solutions by pervaporation (PV) method. The tests used a two-layer backing, porous, ultrafiltration commercial membrane (PS20), which consisted of a supporting polyester layer and an active polysulfone layer. The active layer of PV membranes was obtained in an aqueous environment, in the presence of a surfactant, by cross-linking a 5 wt.% aqueous solution of polyvinyl alcohol (PVA)-using various amounts of cross-linking substances: 50 wt.% aqueous solutions of glutaraldehyde (GA) or citric acid (CA) or a 40 wt.% aqueous solution of glyoxal. An ethylene glycol oligomer (PEG 200) was also used to prepare active layers on PV membranes. Witch its help a chemically cross-linked hydrogel with PVA and cross-linking reagents (CA or GA) was formed and used as an active layer. The manufactured PV membranes (PVA/PSf/PES) were used in the desalination of water with a salinity of 35‱, which corresponds to the average salinity of oceans. The pervaporation method was used to examine the efficiency (productivity and selectivity) of the desalination process. The PV was carried at a temperature of 60 °C and a feed flow rate of 60 dm3/h while the membrane area was 0.005 m2. The following characteristic parameters of the membranes were determined: thickness, hydrophilicity (based on contact angle measurements), density, degree of swelling and cross-linking density and compared with the analogous properties of the initial PS20 backing membrane. The physical microstructure of the cross-section of the membranes was analyzed using scanning electron microscopy (SEM) method.

Deciphering Permian wetland deposits of the Parnaíba Basin through an integrated study of lithofacies and palynofacies in Western Gondwana

During the Permian, the northwestern portion of the supercontinent Gondwana experienced significant climate changes, among which the increasing aridity in the Parnaíba Basin, located between Brazil's northern and northeastern regions. The marine influence associated with the Panthalassa Ocean, evident in the Silurian and Devonian deposits, was progressively attenuated in the late Carboniferous, culminating in extensive continental deposits during the Permian and the Early Triassic in this region. In this paper, we present the first palynofacies analysis of the Permian Pedra de Fogo Formation, conducted concurrently with the description and association of sedimentary facies from outcrops located in the state of Maranhão, southwest of the Parnaíba Basin. A total of 15 m of sedimentary succession was described, and 28 samples were selected for palynofacies analysis. As a result, we identified six sedimentary facies, which were grouped into two distinct facies associations: Fa1 – Central Lake and Fa2 – Playa Lake. The palynofacies analysis considered the sedimentary organic matter, classifying it into amorphous organic matter, phytoclasts (subdivided into eight subgroups), and palynomorphs (with six subgroups). Integrating the results enabled an understanding of the depositional context, which is closely related to water dynamics and climate seasonality. The shallow lake system interpreted during the wet phases recorded interruptions in the normal sedimentation of the central lake due to turbidite deposits associated with ephemeral rivers. Conversely, during dry phases, salt precipitation occurred with subsequent substitution and aerial exposure of the surface when the water balance was negative. Eodiagenetic events were inferred and are considered throughout the article. The alternation of the hydrological regime allowed the deposition in proximal, transitional, and distal environments, creating a distinctive mosaic of wetland landscapes. The data presented indicate humid conditions within a context of increasing aridity in the studied location, particularly in the upper part of the Pedra de Fogo Formation.

Historical drivers and future streamflow variations of the Kura River in the Western Transcaucasia region of Georgia: Analysis of tree-ring chronologies from 1720 to 2021 CE

In this paper, we conduct a dendrochronological study in the Western Transcaucasia region of Georgia to elucidate the relationship between tree growth and climatic variables (temperature, precipitation, and streamflow) in order to reconstruct the paleohydrology of the Kura River and to assess the impacts of climate change on water resources. We analyzed tree-ring chronologies from 1720 to 2021 CE, and analysis of July–August streamflow revealed five wet phases (1739–1753, 1764–1807, 1811–1831, 1962–1988 and 2000–2019 CE ranging in duration from 11 to 49 years) when streamflow exceeded the long-term mean, and four dry phases (1720–1738, 1832–1881, 1936–1961 and 1989–1999 CE) when streamflow was below average. The most extreme wet and dry years were 1771 and 1851 CE, respectively. Spatial correlation patterns of Kura River reconstructed runoff against sea level pressure (SLP) are negative in the Arctic and positive in mid- to high-latitude Eurasia. The Arctic Oscillation (AO)/North Atlantic Oscillation (NAO), and solar activity are important drivers of hydroclimatic conditions in the Mediterranean region, by modifying the location of high-pressure areas and large-scale atmospheric circulations. Comparison of our Kura streamflow reconstructions and data in the Old World Drought Atlas (OWDA) reveals a moderately positive correlation (0.40) throughout the study period, being strongest over the Southern Caucasus and Eastern Turkey. This validates the drought signals and emphasizes the importance of using multi-proxy approaches, supported by spatially resolved data, to enhance understanding of regional hydroclimatic variability and drought patterns. We additionally conducted future streamflow scenarios, most notably under the high-emission SSP585 scenario, in line with global trends in CMIP6 projections. Our streamflow results indicate a trend towards increasing drought severity, which highlights the need for urgent adaptation and mitigation strategies in water resource management in this region. Ultimately, this study provides valuable information on historical hydroclimatic conditions in the Kura River Basin, which help to develop strategies to mitigate the hydrologic impacts of climate change in the Western Transcaucasia Caucasus region. We further highlight the importance of regional and global teleconnections for understanding regional hydrological dynamics.

Exploring trace fossils on megafauna remains from the Quaternary Lagoa da Pedra tank deposit, northeastern Brazil

The natural tank deposits of northeastern Brazil, particularly those with sedimentary filling, are notable for preserving extensive Quaternary megafauna fossil remains. While previous studies have primarily emphasized taxonomic aspects, ichnological evidence has also been documented. This study reports new trace fossils on megafauna remains from the Lagoa da Pedra natural tank (state of Pernambuco, Brazil), shedding light on behavioral interactions between megafauna taxa and other organisms. Four distinct traces, corresponding to three ichnogenera (Cubiculum, Nihilichnus, and Machichnus) were identified on post-cranial bones, three from Eremotherium laurillardi and one from Xenorhinotherium bahiense. Holes and pits (Nihilichnus nihilicus) on the radius of X. bahiense and the rib of E. laurillardi, along with furrows and scratches (Machichnus fatimae and M. bohemicus) on the rib of E. laurillardi, are attributed to scavenging activities, likely by carnivores. Additionally, furrows observed on the rib and vertebra of E. laurillardi are associated with dermestid insect pupation (Cubiculum ornatus and C. cooperi). These pupal chambers of dermestid insects (Cubiculum) suggest that the final stage of the dry carcasses, before the final burial, probably happened under the dry phase during the late Pleistocene-early Holocene.

Macroinvertebrate, algal and diatom assemblages respond differently to both drying and wetting transitions in non‐perennial streams

Abstract Biological assemblages in streams are influenced by hydrological dynamics, particularly in non‐perennial systems. Although there has been increasing attention on how drying impacts stream organisms, few studies have investigated how specific characteristics of drying and subsequent wetting transitions influence biotic responses via resistance and resilience traits. Here, we characterized how hydrologic metrics, including those quantifying drying and wetting transitions as well as dry and wet phases, alter diversity and composition of three aquatic assemblages in non‐perennial streams in southern California: benthic macroinvertebrates, soft‐bodied algae and diatoms. We found that flow duration prior to sampling was correlated with variation in macroinvertebrate and soft‐bodied algal assemblage composition. The composition and richness of diatom assemblages, however, were predominantly influenced by the drying start date prior to sampling. Contrary to other studies, the duration of the dry phase prior to sampling did not influence the composition or richness of any assemblage. Although our study was conducted within a region in which each assemblage experienced comparable environmental conditions, we found no single hydrologic metric that influenced all assemblages in the same way. The hot‐summer Mediterranean climate of southern California likely acts as a strong environmental filter, with taxa in this region relying on resistance and resilience adaptations to survive and recolonize non‐perennial streams following wetting. The different responses of algal and diatom assemblages to hydrologic metrics suggest greater resilience to drying and wetting events, particularly for primary producers. As drying and wetting patterns continue to change, understanding biodiversity responses to hydrologic metrics could inform management actions that enhance the ecological resilience of communities in non‐perennial streams. In particular, the creation and enhancement of flow regimes in which natural timing and duration of dry and wet phases sustain refuges that support community persistence in a changing environment.

Separation and extraction of NH4Br and (K,NH4)2SO4 from 1-Bromooctane production wastewater by crystallization method

This work provides a method for the separation and extraction of bromine salts from bromine-containing wastewater by crystallization. Wastewater from the production of 1-Bromooctane is rich in potassium and bromine salts. This will allow for the recycling of chemical resources in this aqueous salt system. Based on the need for the process design of the new method, the solubility phase equilibrium of the quaternary K+,NH4+//SO42-,Br-–H2O system at 298.15 K and 323.15 K was investigated in this paper by using the isothermal dissolution equilibrium method, and the dry basis phase diagrams were plotted using the experimental data. And the equilibrium solid phase composition was determined by X-ray diffraction. At 298.15 K, the dry phase diagram of the quaternary system K+,NH4+//SO42-,Br-–H2O consists of three invariant points and five crystalline regions (K2SO4, (NH4)2SO4, (K,NH4)2SO4, (K,NH4)Br, (NH4,K)Br). At 323.15 K, there is one invariant point in the phase diagram of this quaternary system and three crystalline regions((K,NH4)2SO4, (K,NH4)Br, (NH4,K)Br). The (K,NH4)Br crystallization zone grows while the (NH4,K)Br crystallization zone decreases with increasing temperature, according to comparisons of the dry basis phase diagrams of this quaternary system at different temperatures. Crystallization zones of solid solution (K,NH4)2SO4 replaced the K2SO4 and (NH4)2SO4 single salt crystallization zones at the same time. The Pitzer model was used to calculate the solubility of this quaternary system at 298.15 K. The results showed that the experimental values were in good agreement with the calculated values. Based on the theoretical analysis of the dry phase diagram of the quaternary system K+,NH4+//SO42-,Br-–H2O, a process route for salt extraction using bromine-containing wastewater generated from the production of 1-Bromooctane was proposed and designed. The new process was experimentally verified to be technically feasible to obtain NH4Br with 99.01 % purity and (K,NH4)2SO4. The process has significant advantages, such as production safety, low input costs and no three-waste emissions.

Climate variability in a 3.8 Ma old sedimentary record from the hyperarid Atacama Desert

The hyperarid Atacama Desert is one of the driest and oldest deserts on Earth, rendering it a valuable climate archive. However, unraveling its past climate is particularly challenging and the few studied paleoclimate records of the region reveal strong temporal and spatial variabilities. To enhance our understanding of these dynamics we investigated a sedimentary record in the Yungay valley located in the southern hyperarid Atacama Desert. We employed paleomagnetic and radiocarbon dating, and for the first time for Atacama Desert sediments, a meteoric 10Be/9Be based method for determining the depositional age. The respective 4.20 m deep profile comprises a lower alluvial fan deposit with a maximum age of 3.8 ± 0.8 Ma, and an upper 1.84 m thick clay pan deposit that has accumulated over the last 19 ka. Different proxies including grain size, salt concentration, and elemental composition indicate an aridity increase around 2.3 Ma ago and repeated dry and wet phases during the late Pleistocene and the Holocene. The latter climatic shifts can be assigned to variabilities of the South American Summer Monsoon and El Niño Southern Oscillation with moisture sources from the Atlantic and the Pacific Ocean, respectively. This study provides deeper insights into the heterogeneous climate of the hyperarid Atacama Desert and underlines the importance of interdisciplinary investigations to decipher climate systems and their effect on potential habitable regions in such an extreme environment.

A simple two-phase approach to predict moisture-dependent thermal conductivity for porous materials

This study develops a generalized solution for moisture-dependent thermal conductivity (λeff) in porous media, utilizing readily available parameters. By introducing arbitrary dry and saturated phases, the tri-phase model (solid, gas, and water) is simplified into a two-phase model. Seven analytical solutions are adapted, including series-parallel, Maxwell-Eucken, Landauer's, exponential, and Somerton's relations. The proposed method requires only two parameters to predict λeff under different degrees of saturation (Sr): effective dry thermal conductivity (λdry, where Sr = 0) and effective saturated thermal conductivity (λsat, where Sr = 1). In the absence of direct λsat measurement, this λsat can be obtained using λdry and the parallel relation for highly porous media, and using Landauer's relation for medium-density materials. Validation results indicate that both Landauer's and exponential relations provide the upper bound and lower bounds, respectively, for λeff. For medium-density materials, the upper bound aligns with the parallel relation and the lower bound aligns with Landauer's relation.

Surface weathering process of earthen heritage under dry-wet cycles: A case study of Suoyang City, China

Dry-wet cycle is a key factor in surface weathering of earthen heritage, which remains insufficiently explained. It involves the interaction of humidity, stress, and damage. Using the RFPA (realistic failure process analysis) numerical method, this study reproduced the processes of humidity diffusion, deformation, stress, and damage evolution under dry-wet cycles in the soil site of Suoyang City, China. The numerical results indicate that the drying phase following rainfall has the most significant deteriorative impact on the earthen heritage. The evaporation of surface moisture during this phase causes volume shrinkage, which in turn generates tensile stress and leads to the formation of numerous desiccation cracks. Desiccation cracks provide channels for moisture diffusion, which further exacerbates generation of the cracks, leading to a mutual promotion between the two phenomena. Furthermore, during the wetting phase, the model elements undergo hygroscopic expansion, resulting in a slight increase in strain and displacement. Previously formed cracks may exhibit temporary narrowing or closure, but will revert during the subsequent drying phase. Ultimately, the overall displacement increases with the number of dry-wet cycles. The findings provide a theoretical foundation for protection against surface weathering and other damage in earthen heritage in arid regions.

Prewetting couples membrane and protein phase transitions to greatly enhance coexistence in models and cells.

Both membranes and biopolymers can individually separate into coexisting liquid phases. Here we explore biopolymer prewetting at membranes, a phase transition that emerges when these two thermodynamic systems are coupled. In reconstitution, we couple short poly-L-Lysine and poly-L-Glutamic Acid polyelectrolytes to membranes of saturated lipids, unsaturated lipids, and cholesterol, and detect coexisting prewet and dry surface phases well outside of the region of coexistence for each individual system. Notability, polyelectrolyte prewetting is highly sensitive to membrane lipid composition, occurring at 10 fold lower polymer concentration in a membrane close to its phase transition compared to one without a phase transition. In cells, protein prewetting is achieved using an optogenetic tool that enables titration of condensing proteins and tethering to the plasma membrane inner leaflet. Here we show that protein prewetting occurs for conditions well outside those where proteins condense in the cytoplasm, and that the stability of prewet domains is sensitive to perturbations of plasma membrane composition and structure. Our work presents an example of how thermodynamic phase transitions can impact cellular structure outside their individual coexistence regions, suggesting new possible roles for phase-separation-prone systems in cell biology.

Nellix Device Failure Mechanisms Analysis on Explanted Grafts.

To understand possible reasons for poor durability of the Nellix (Endologix Inc., Irvine, USA) endovascular aneurysm sealing (EVAS) device. 21 Nellix endoprostheses explanted for endoleaks and migration underwent visual examinations of stent structures and instrumental examinations of the polymer endobags on 4 devices. We harvested 2.0-gram polymer slices out of each of them and tested the samples in an in vitro implantation replication that included wet and dry exposures. During the wet phase, we placed samples in a beaker with saline, mimicking the filling of the endobags during implantation. An exposure to a 37°C environment with 60% humidity during the dry phase replicated the postimplantation conditions inside the aneurysmal sac. Iatrogenic defects affected 16 (76%) metal stents and 20 (95%) endobags. The polymer was disintegrated owing to degradation in 15 (71%) cases. The polymer could lose more than 70% of its initial weight when partially dehydrated and regain 80% when placed in saline. We observed volume decrease and polymer fragmentation during these study phases. The polymer can lose weight and volume while it dehydrates. This structural degradation of the polymer could lead to the development of endoleaks and/or migration of the device. Based on the results of previous investigations, due to possible endovascular device degradation, patients with endografts should be offered life-long surveillance, and the Nellix device is no exception. Herein we suggest polymer degradation as one of the possible reasons for the device failure. Although Nellix has been withdrawn from the market, there are numerous patients with this type of endograft. Due to its unpredictable performance in the medium and long term, these patients should be recommended enhanced life-long surveillance every 6 months. Any suspicious conditions during the follow-up must be taken seriously and explantation should be considered.

Impact of joint dispatch of reservoir group on water pollution incident in drinking water source area

To reduce the harm of water contamination incidents in drinking water source areas (DWSAs) and explore feasible approaches, the research developed a hydrodynamic water quality model for DWSAs based on two dimensional water quality and quantity equations, Geographic Information System (GIS), and Digital Elevation Model (DEM). The Heshangshan Drinking Water Source Area (HDWSA) in the Three Gorges Reservoir Area (TGRA) was selected as the research area, with total phosphorus (TP) as the representative pollutant in the water. The research investigated the changes in TP content during various hydrological phase under pollution incident, compared the duration and trends of TP concentration exceeding standard value before and after joint reservoir group dispatch. The results showed that the migration speed of TP pollutants varied from slowest to fastest in the following order: dry phase, recession phase, storage phase, and flood phase. Under pollution incident condition, the time demanded for TP content to meet standard value in each water phase was 36 min (dry phase), 33 min (recession phase), 30 min (storage phase), and 27 min (flood phase). The joint dispatch group 1–3 shortened the time required to meet standard value by 6–13 min (dry phase), 5–11 min (recession phase), 4–9 min (storage phase), and 3–7 min (flood phase). The trend of TP concentration before and after joint dispatch showed four stages: significant increase, sharp decrease, rapid decrease, and slow decrease. Joint dispatch of reservoir group can effectively reduced the TP concentration in DWSA under pollution incident.

Radio Frequency Vacuum Drying Study on the Drying Characteristics and Quality of Cistanche Slices and Analysis of Heating Uniformity.

To fully leverage the advantages of both hot air drying and radio frequency vacuum drying, a segmented combination drying technique was applied to post-harvest Cistanche. This new drying method involves using hot air drying in the initial stage to remove the majority of free water, followed by radio frequency vacuum drying in the later stage to remove the remaining small amount of free water and bound water. During the radio frequency vacuum drying (RFV) phase, the effects of temperature (45, 55, and 65 °C), vacuum pressure (0.020, 0.030, and 0.040 MPa), plate spacing (65, 75, and 85 mm), and slice thickness (4, 5, and 6 mm) on the drying characteristics, quality, and microstructure of Cistanche slices were investigated. Additionally, infrared thermal imaging technology was used to examine the surface temperature distribution of the material during the drying process. The results showed that compared to radio frequency vacuum drying alone, the hot air-radio frequency combined drying significantly shortened the drying time. Under conditions of lower vacuum pressure (0.020 MPa), plate spacing (65 mm), and higher temperature (65 °C), the drying time was reduced and the drying rate increased. Infrared thermal imaging revealed that in the early stages of hot air-radio frequency vacuum combined drying, the center temperature of Cistanche was higher than the edge temperature. As drying progressed, the internal moisture of the material diffused from the inside out, resulting in higher edge temperatures compared to the center and the formation of overheating zones. Compared to natural air drying, the hot air-radio frequency vacuum combined drying effectively preserved the content of active components such as polysaccharides (275.56 mg/g), total phenols (38.62 mg/g), total flavonoids (70.35 mg/g), phenylethanoid glycosides, and iridoids. Scanning electron microscopy observed that this combined drying method reduced surface collapse and cracking of the material. This study provides theoretical references for future drying processes of Cistanche.

Unravelling large-scale patterns and drivers of biodiversity in dry rivers

More than half of the world’s rivers dry up periodically, but our understanding of the biological communities in dry riverbeds remains limited. Specifically, the roles of dispersal, environmental filtering and biotic interactions in driving biodiversity in dry rivers are poorly understood. Here, we conduct a large-scale coordinated survey of patterns and drivers of biodiversity in dry riverbeds. We focus on eight major taxa, including microorganisms, invertebrates and plants: Algae, Archaea, Bacteria, Fungi, Protozoa, Arthropods, Nematodes and Streptophyta. We use environmental DNA metabarcoding to assess biodiversity in dry sediments collected over a 1-year period from 84 non-perennial rivers across 19 countries on four continents. Both direct factors, such as nutrient and carbon availability, and indirect factors such as climate influence the local biodiversity of most taxa. Limited resource availability and prolonged dry phases favor oligotrophic microbial taxa. Co-variation among taxa, particularly Bacteria, Fungi, Algae and Protozoa, explain more spatial variation in community composition than dispersal or environmental gradients. This finding suggests that biotic interactions or unmeasured ecological and evolutionary factors may strongly influence communities during dry phases, altering biodiversity responses to global changes.

How Can Seasonality Influence the Performance of Recent Microwave Satellite Soil Moisture Products?

In addition to technical issues related to the instruments used, differences between soil moisture (SM) measured using ground-based methods and microwave remote sensing (RS) can be related to the main features of the study areas, which are intricately connected to hydraulic–hydrological conditions and soil properties. When long-term analysis is performed, these discrepancies are mitigated by the contribution of SM seasonality and are only evident when high-frequency variations (i.e., signal anomalies) are investigated. This study sought to examine the responsiveness of SM to seasonal variations in terrestrial ecoregions located in areas covered by the in situ Romanian Soil Moisture Network (RSMN). To achieve this aim, several remote sensing-derived retrievals were considered: (i) NASA’s Soil Moisture Active and Passive (SMAP) L4 V5 model assimilated product data; (ii) the European Space Agency’s Soil Moisture and Ocean Salinity INRA–CESBIO (SMOS-IC) V2.0 data; (iii) time-series data extracted from the H115 and H116 SM products, which are derived from the analysis of Advanced Scatterometer (ASCAT) data acquired via MetOp satellites; (iv) Copernicus Global Land Service SSM 1 km data; and (v) the “combined” European Space Agency’s Climate Change Initiative for Soil Moisture (ESA CCI SM) product v06.1. An initial assessment of the performance of these products was conducted by checking the anomaly of long-term fluctuations, quantified using the Absolute Variation of Local Change of Environment (ALICE) index, within a time frame spanning 2015 to 2020. These correlations were then compared with those based on raw data and anomalies computed using a moving window of 35 days. Prominent correlations were observed with the SMAP L4 dataset and across all ecoregions, and the Balkan mixed forests (646) exhibited strong concordance regardless of the satellite source (with a correlation coefficient RALICE > 0.5). In contrast, neither the Central European mixed forests (No. 654) nor the Pontic steppe (No. 735) were adequately characterized by any satellite dataset (RALICE < 0.5). Subsequently, the phenological seasonality and dynamic behavior of SM were computed to investigate the effects of the wetting and drying processes. Notably, the Central European mixed forests (654) underwent an extended dry phase (with an extremely low p-value of 2.20 × 10−16) during both the growth and dormancy phases. This finding explains why the RSMN showcases divergent behavior and underscores why no satellite dataset can effectively capture the complexities of the ecoregions covered by this in situ SM network.

Optimizing the secondary drying phase of a continuous Spin-Freeze Drying process: A semi-mechanistic modelling approach

Over the past decade, continuous spin freeze-drying technology has emerged as a promising alternative to conventional batch freeze-drying, effectively addressing many of the latter’s inherent disadvantages. Much of the focus during this period has been on controlling and optimizing the primary drying phase of this process. However, optimizing the secondary drying step is equally critical for the overall efficiency of the process. The primary aim of this study was to develop a comprehensive semi-mechanistic model for the secondary drying phase in continuous spin freeze-drying, accounting for the effects of process settings such as freezing rate and product temperature on desorption kinetics. Additionally, the study aimed to address discrepancies between conventional desorption models, typically applied in batch freeze-drying, and the observed data in this research. To achieve this, a residual moisture-dependent activation energy was introduced to improve the accuracy of the desorption model. Using NIR spectroscopy and IR-thermography, unknown model parameters could reliably be estimated using a simple and fast procedure. The calibrated model successfully predicted the final moisture content with an accuracy within 0.11% of the measured value under previously untested process conditions. Ultimately, the proposed semi-mechanistic model demonstrated its reliability in predicting the impact of new process conditions on both product temperature and residual moisture over time, enabling the development of a practical design space.

Quaternary environment and climate change reconstruction from geochemical and geoarchaeological evidences of paleosols in east-central Barind, NW Bangladesh

This research focuses on analyzing paleosols, major and trace element geochemistry, organic carbon levels, and geo-archaeological aspects of Quaternary deposits investigated in two sedimentary successions located in the east-central Barind region of NW Bangladesh. Several factors that influence the paleosol development can be used to decipher the paleoenvironment and paleoclimatic conditions of the study area. Sedimentary succession of the studied sections have been grouped into two broad categories i.e., Gray unit/Newer Alluvium (NA) of Late Holocene and Red unit/Older Alluvium (OA) of Early Pleistocene age. Some geoarchaeological evidences have been found at the bottom of the gray unit and the top of the red unit in Durgadaha (DD) section indicating the existence of paleo-settlement at about ∼1300 years BP. The age is determined by the relative dating of several artifacts found at the paleo-settlement surface. Interpretation of several field characteristics and geochemical parameters i.e., clayeyness, salinization, base loss, calcification, leaching (Ba/Sr), aeolian input (Zr/Al), CIA, CIW, CIA-K, etc. revealed that the paleosols in gray unit are weakly developed; whereas, paleosols in red unit are relatively moderate, strong to very strongly developed. In the red unit, the MAP and MAT range from 1000 ± 181 mm to 1478 ± 181 mm and 9° ± 4.4°–14° ± 4.4 °C respectively. On the other hand, MAT ranges from 23.1° ± 0.6 °C to 28.3° ± 0.6 °C in gray unit paleosols. Depending on the depositional pattern and estimated MAT, five short-term climatic cycles (i.e., alternating phases of dry and wet) have been recognized in gray/newer alluvium units during the last 1300 years. The demise of paleo settlement (1300 years BP) due to the abrupt climatic change towards a dry and cooler phase where the MAT was estimated as 23.1° ± 0.6° which is at least 3 °C lower than the present. This study also revealed that the estimated MAP and MAT are more analogous to paleoclimatic records of the Asian regions.

Reconstruction of late Holocene palaeoenvironmental and palaeohydrological changes using multi-proxy analysis of Sattal lake sediments, Kumaun lesser Himalaya, India

The present study aims to investigate the palaeoenvironmental changes around Sattal Lake, Kumaun Lesser Himalaya spanning the last 1670 years. Based on multi proxy analysis (i.e., grain size, mineral magnetism, clay mineralogy, Total Organic Carbon (TOC) and carbon isotopes), supported by a robust radiocarbon chronology, three major environmental phases were identified. Warm, wet phases occurred between 1,150–650 cal yr BP and 260 cal yr BP to the present. These phases coincide closely with the Medieval Climatic Anomaly (MCA) and modern warming, respectively. These warm/wet events were due to elevated precipitation, resulting in high lake levels and an expansion of the lake margin, which were marked by lower δ13C values, comparatively higher sand concentration, TOC values and magnetic susceptibility (χlf). The inference of a modern warm phase is supported by high resolution instrumental data. The MCA, which is marked by elevated amounts of coarse grained (sand) detrital material, is inferred to be an interval of strengthened of monsoonal intensity, which correlates with available monsoon records from various continental paleoclimate archives. Following the MCA a cold and dry phase was observed to occur between 610 and 260 cal yr BP, corresponding to the Little Ice Age (LIA). The LIA, which was characterized by high silt and clay concentration, high δ13C, low TOC and reduced magnetic susceptibility (χlf), is inferred to represent an interval of low lake levels, likely reflecting an episode of weakened monsoonal intensity.

Compaction behaviour of flax-preforms during forming for composites

Flax reinforced composites are becoming popular in automotive and civil industries due to their green production and recycling, and for good specific strength. To manufacture composites, firstly a multi-layer of flax preforms undergo compressive pressure before resin impregnation that causes nesting, wherein, fibres of one layer fit into the adjacent layers. This debulking of the preforms under compression is an important feature that determines the fibre volume fraction of composites. In this study, four flax structures such as: nonwoven tapes, unidirectional fabric, hopsack fabric, and nonwoven tape with glass veils were investigated for compaction behaviour under pressures between 1 and 10 bars, in single and multi-layer states, in dry and wet states, under different loading cycles, and in different ply orientations (0°/0° and 0°/90°). Nesting has been calculated for single- and multi-layer stacks. It was observed that the nonwoven structures shown greater thickness reduction compared to woven structures. Nesting factor was found to be higher than 1 for the nonwoven structures under compaction, indicating lower nesting, compared to the woven structures. In terms of thickness under repeated compaction, the reduction was the highest during first compressions, compared to the 2nd and 3rd compressions, for all the structures. When wettability was examined, thickness reduction for wet plies was higher for all the structures, compared to the dry phase. Finally, a comparative study was shown to evaluate fibre volume fractions of the composites.