Variation In Content Research Articles

Starch molecular structure, physicochemical properties and in vitro digestibility of Ethiopian malt barley varieties

Characterization of local varietal barley quality diversity can help boost further development of novel value-added utilization of the grain. Therefore, in this study starch was isolated from 11 Ethiopian malting barley varieties to determine starch structural, pasting, thermal and digestibility characteristics, and their inter-relationships. The varieties showed significant differences in all amylopectin chain length fractions, and the A, B1, B2 and B3 chains ranged from 25.4 to 30.1, 47.4–50.1, 14.3–16.0 and 7.8–9.0 %, respectively. The varieties also exhibited significant variation in amylose content, relative crystallinity, absorbance peak ratios, pasting and thermal properties. Moreover, on average about 83 % raw starch of the varieties was classified as slowly digestible and resistant, whereas after gelatinization this was reduced to 9 %. Molecular and crystalline structures were strongly related to pasting properties, thermal characteristics and in vitro digestibility of the starches. The study provides information on some starch quality characteristics and the inter-relationships among the parameters, and might inspire further studies to suggest possible target-based starch modifications, and future novel utilization of barley. More studies are required to investigate the association of starch quality parameters with malting quality attributes.

Experimental investigation on the permeability of gap-graded soil due to horizontal suffusion considering boundary effect

The boundary condition is a crucial factor affecting the permeability variation due to suffusion. An experimental investigation on the permeability of gap-graded soil due to horizontal suffusion considering the boundary effect is conducted, where the hydraulic head difference (ΔH) varies, and the boundary includes non-loss and soil-loss conditions. Soil samples are filled into seven soil storerooms connected in turn. After evaluation, the variation in content of fine sand (ΔRf) and the hydraulic conductivity of soils in each storeroom (Ci) are analyzed. In the non-loss test, the soil sample filling area is divided into runoff, transited, and accumulated areas according to the negative or positive ΔRf values. ΔRf increases from negative to positive along the seepage path, and Ci decreases from runoff area to transited area and then rebounds in accumulated area. In the soil-loss test, all soil sample filling areas belong to the runoff area, where the gentle-loss, strengthened-loss, and alleviated-loss parts are further divided. ΔRf decreases from the gentle-loss part to the strengthened-loss part and then rebounds in the alleviated-loss part, and Ci increases and then decreases along the seepage path. The relationship between ΔRf and Ci is different with the boundary condition. Ci exponentially decreases with ΔRf in the non-loss test and increases with ΔRf generally in the soil-loss test.

Mutual Effect Between Moisture Transfer and Mechanical Response in Infill Masonry Walls of Reinforced Concrete Building Envelope

The external envelope of buildings with reinforced concrete structures (RCS buildings) is subjected to environmental actions, particularly related to wind-driven rain (WDR), external humidity variations, and rising dampness, which can cause significant variations in moisture content to their unreinforced masonry (URM) infill walls, mainly associated to water penetration across that envelope. The consequent moisture transfer across the envelope can change the mechanical response of the URM infill walls and lead to their cracking, which could aggravate the referred water penetration, with a subsequent increase in the risk of building envelope degradation. In reverse, the effects of mechanical loads on moisture transfer across that envelope can be also relevant, in terms of change in the moisture content of these URM infill walls. The aim here is to analyze this type of mutual effect between moisture transfer and mechanical response in URM infill walls of RCS buildings. Essential elements about the characteristics of moisture transfer across URM infill walls and of the interface resistance with moisture flows are summarily described, and the essential evaluation of the mechanical behavior of URM infill walls when subjected to moisture variations is carried out. Moisture transport characteristics are discussed, focusing on analyses of the behavior of masonry elements when subjected to moisture variations. An initial assessment of the mechanical behavior of URM infill walls when subjected to different moisture variations is made through a compression test of a brick masonry specimen with variable moisture content. Following that analysis, an evaluation is made of the moisture transfer in URM infills, as well as the influence of the interface between layers in that moisture transfer and, subsequently, an assessment is made of hygromechanical couplings. Finally, elements for prevention about the causes of degradation of URM infill related to humidity and mechanical actions in the RCS building envelope are discussed.

Investigation of KOH‐doped PVA‐based membrane electrolytes cross‐linked with tartaric acid for DMAFCs

AbstractThis research focused on the development of anion exchange membrane electrolytes suitable for direct methanol alkaline fuel cells (DMAFC) by employing a straightforward blending and solution casting process complemented by subsequent heat treatment. Tartaric acid (TA) was employed as a cross‐linking agent to enhance the heat resistance and structural integrity of the PVA matrix. The distinctive attributes of the PT (PVA and tartaric acid blend) samples, including water absorption and swelling capacity, were comprehensively investigated with respect to variations in both TA content (expressed as wt. % relative to the PVA matrix) and alterations in the duration of thermal treatment. Cross‐link formation between the polymer chains and TA was determined using FTIR analysis. The samples were subjected to comprehensive analysis, encompassing the determination of crystallinity via X‐ray diffraction (XRD), assessment of thermal stability using thermogravimetric analysis (TGA), investigation of morphology through scanning electron microscopy (SEM), and measurement of ionic conductivity using AC Impedance spectroscopy. The methanol permeability was measured to determine the selectivity values of the membranes. Subsequently, within the DMAFC system, the performances of the PT30‐3, PT40‐2, and PT40‐3 membranes, which exhibited the highest selectivities, were assessed. The contribution of the crosslinking process to the resistance of the membranes to oxidative conditions, as represented by the Fenton solution, was evaluated to assess the chemical stability of the membranes. The maximum power densities for PT30‐3 and PT40‐3 membranes reached 15.29 and 12.53 mW/cm2 at 30°C, respectively. These figures exhibited a notable increase, reaching 32.73 mW/cm2 for PT30‐3 and 31.72 mW/cm2 for PT40‐3 when the temperature was elevated to 60°C. This study confirmed that the crosslinking strategy using TA assisted by thermal treatment is very simple and competitive compared with other techniques reported in the literature. PT membranes are promising candidates for commercialization and utilization in DMAFC owing to their environment‐friendly nature, cost‐effectiveness, and high efficiency.Highlights TA cross‐linking improved the thermal and dimensional stability of PVA. The PT membrane properties varied with TA content and thermal treatment time. Some electrolytes in this study outperformed those previously reported for DMAFC. PT membranes offer efficiency, cost‐effectiveness, and eco‐friendliness for DMAFCs.

Cathodoluminescence and geochemical characteristics of Apatite: Implications for mineral exploration in the Xiongcun District, Tibet, China

Apatite grains from the No. 2 porphyry Cu–Au deposit in the Xiongcun district of Tibet, China, have a range of physical and compositional features. This study investigates the potential use of apatite associated with hydrothermal alteration as a tool for mineral exploration. In situ textural, cathodoluminescence (CL), and chemical analyses were performed on thin sections containing apatite from various alteration zones in the deposit. No clear variation was seen in apatite from rocks of the potassic, sodic–calcic, chlorite–sericite, phyllic, and propylitic alteration zones using visible light and scanning electron microscopy; however, distinct variations were observed in optical cathodoluminescence (OP-CL) (dark yellow to green, orange to green, yellow–brown to green, yellow-orange to brown, and light yellow–brown to green luminescence for the respective zones). The alteration-related differences in luminescence were a result of the interaction between Fe and Mn; the Na and Cl contents; and depletion in total heavy rare earth elements (ΣHREE) and Y. The variations in the REE contents of apatite from different types of altered rock record reactions with Cl- and F-rich fluids. The partitioning behavior of Cl between apatite and hydrothermal fluids is influenced by pressure, temperature, pH, and fluid composition, whereas the partitioning of F between apatite and fluids is dependent on the fluid composition and not the temperature. At high temperatures, Eu3+ is reduced to Eu2+, which results in negative Eu anomalies in apatite from the potassic-altered rocks and propylitic-altered rocks. Apatite grains in the sodic–calcic-altered rocks and chlorite–sericite-altered rocks show a similar enrichment in light REEs (LREEs) that resulted from REE and Y incorporation as follows: Na+ + (Y + REE)3+ = 2Ca2+. Apatite grains in the phyllic-altered rocks are enriched in the middle REEs. This study confirms that the luminescence, chemical composition (including Fe, Mn, Na, Cl, ΣHREE, and Y contents), and REE patterns of apatite can be affected by hydrothermal alteration; therefore, these results may be used to constrain the evolution of ore-forming hydrothermal fluids and may offer an effective tool for mineral exploration.

Study on mechanical properties and microstructure of fly-ash-based geopolymer for solidifying waste mud

The chemical solidification of construction waste mud presents a strategy for mitigating environmental concerns as well as addressing problematic geotechnical engineering properties. The present study explores the efficacy of utilizing fly ash (FA)-based geopolymer, activated by calcium carbide residue (CCR) and sodium silicate solution (NS), for waste mud solidification. An unconfined compressive strength (UCS) test was conducted to ascertain the optimal CCR/NS ratio. Supplementary tests were executed to examine factors such as water content, pH level, X-ray diffractometry (XRD), scanning electron microscopy (SEM), and natural dehydration. According to the UCS results, an optimal 28-day strength of 2.2 MPa was observed when employing a CCR/NS ratio of 6:4. A notable reduction in the water content of the mud was achieved in the short term, with the most effective results observed at a pH level of 12. Microstructural analyses indicated that calcium silicate hydrate (CSH) and aluminosilicate-Na hydrate (NASH) acted as the primary cementitious products, filling pores and creating bonds with particles to facilitate strength development. Variations in crack morphology and water content during the natural dehydration process were also analyzed for both solidified and untreated mud. The findings suggest that solidified mud holds promise for application in subgrade engineering projects, potentially diverting significant volumes of waste mud and industrial by-products such as CCR and FA away from landfills.

Performance Evaluation of Fiber Near-Infrared (NIR) Optic Probes for Quality Control of Curd Hardness in Cheese Produced by Spray-Dried Milk

This study aims to provide the dairy industry with a direct control model focused on milk coagulation by using multifiber probes to determine parameters in the curding process, such as cutting time, at a lower cost. The main objective of the research is to confirm that a multifiber NIR light scattering probe can be used to predict the elastic modulus of curd during milk coagulation in cheese production. Two randomized complete block designs were used with a 3 × 3 factorial arrangement of three protein levels (3%, 3.5% and 4%) and three wavelengths (870 nm, 880 nm and 890 nm). Using a multifiber probe at a wavelength of 880 nm allowed obtaining a better optical response of the sensor during enzymatic milk coagulation than the 870 nm. It showed greater sensitivity to variations in the protein content of the milk and lower variation in the response. The multifiber probe at a wavelength of 880 nm generated a NIR light backscatter profile like those obtained with other systems. The results showed that the prediction model parameters had a variation as a function of the protein content, which opens the possibility of improving the prediction model’s performance substantially. Furthermore, the initial voltage obtained with the probe responded linearly to the different protein levels in milk. This fact would make it possible, at least theoretically, to estimate protein concentration with the same inline probe for G’ determination, facilitating the incorporation of a corrective protein factor in the prediction models using a single instrument.

Seasonal dynamics of bulk milk somatic cell count in grazing Norwegian dairy goats

Somatic cell count (SCC) is a widely used indicator of milk quality in the dairy industry. It is a relatively good indicator of udder health in dairy cows, but strongly confounded by non-infection factors, including season, in dairy goats. This study's objectives were to estimate the variation in SCC explained by season and stage of lactation. We also investigated associations between SCC and other milk quality parameters routinely measured, including total bacterial count, fat, protein, and lactose content, in different seasons and stages of lactation. In this observational study, we included results from the routine analyses of bulk milk samples (n = 5,180) collected every third day in 88 Norwegian goat herds through one year. Herd information was collected via a questionnaire and from the dairy herd recording system. The herds had a notable increase in bulk SCC associated with the pasture season. The median bulk SCC was 470,000 cells/mL in deliveries from the indoor spring period and 1,100,000 cells/mL in the pasture season. During the indoor fall season, when most goat herds are in late lactation, the median SCC was 940,000 cells/mL. The combined effect of the season and herd stage of lactation explained 53.5% of the variation in bulk milk SCC. Fat and protein contents varied significantly with season and stage of lactation, and the association with SCC was non-significant for fat content and explained less than 3% of the variation in protein content. Lactose content was associated with SCC, stage of lactation, and season. Total bacterial count was associated with SCC and the indoor seasons. Determination of normal seasonal variation of goat bulk milk SCC is necessary to establish thresholds for defining milk as abnormal and unacceptable for further processing and improving the usefulness of SCC as a tool for milk quality improvement in dairy goats. The results suggest that SCC thresholds for taking action to improve the milk quality should be adjusted for season and stage of lactation.

Compositional variation and petrogenesis of mare basalts in the Humorum basin: New insights from spectral analysis and crater counting

Pyroxene chemistry estimated using a series of spectral parameters derived from Chandrayaan-I M3 data was used to divide the basalts of Mare Humorum into six compositional units. In order to understand the petrogenetic history of the Humorum basalts, first, the dominant pyroxene end-member composition in each unit is used to estimate the temperature of crystallization; and then crater counting is implemented using craters mapped from the high-resolution Kaguya Terrain Camera data to estimate the age of each unit. The spatial distributions of pyroxene composition and corresponding crystallization temperatures indicate that there is a difference in volcanic activity between the regions corresponding to Units 1–3 (Group I) and the regions corresponding to Units 4–6 (Group II). This observation is further reinforced by analyzing the variation of FeO and TiO2 content across the units. Hence two sources titanium-rich high calcic pyroxene (HCP) and less titanium high calcic pyroxene (HCP) correspond to two groups of basalts in the Humorum area. Furthermore, our new crater-counting analysis reveals that the magmatic activity probably continued until ca. 1.9 Ga in the Humorum basin. To the best of our knowledge, this younger age of volcanism has not been reported before.

Intraspecific Variation of Transposable Elements Reveals Differences in the Evolutionary History of Fungal Phytopathogen Pathotypes.

Transposable elements (TEs) contribute to intraspecific variation and play important roles in the evolution of fungal genomes. However, our understanding of the processes that shape TE landscapes is limited, as is our understanding of the relationship between TE content, population structure, and evolutionary history of fungal species. Fungal plant pathogens, which often have host-specific populations, are useful systems in which to study intraspecific TE content diversity. Here, we describe TE dynamics in five lineages of Magnaporthe oryzae, the fungus that causes blast disease of rice, wheat, and many other grasses. We identified differences in TE content across these lineages and showed that recent lineage-specific expansions of certain TEs have contributed to overall greater TE content in rice-infecting and Setaria-infecting lineages. We reconstructed the evolutionary histories of long terminal repeat-retrotransposon expansions and found that in some cases they were caused by complex proliferation dynamics of one element and in others by multiple elements from an older population of TEs multiplying in parallel. Additionally, we found evidence suggesting the recent transfer of a DNA transposon between rice- and wheat-infecting M. oryzae lineages and a region showing evidence of homologous recombination between those lineages, which could have facilitated such a transfer. By investigating intraspecific TE content variation, we uncovered key differences in the proliferation dynamics of TEs in various pathotypes of a fungal plant pathogen, giving us a better understanding of the evolutionary history of the pathogen itself.

Prosthetic Curricular Threads: Pilot Survey of Clinical Practice and Physical Therapy Education

ABSTRACT Introduction Physical therapists play a critical role in the rehabilitation of persons with limb loss/limb difference. The introduction to the skills and knowledge necessary to provide skilled care occurs during the physical therapist’s education in an accredited physical therapy program. Although clinical practice evolves as technological changes manifest and the evidence base progresses, it is unclear whether physical therapy education is adapting to stay current with clinical practice. Purpose The aim of this study was to explore the alignment of clinical practice with physical therapy education as it relates to prosthetic-specific curriculum. Methods Surveys were sent to inpatient rehabilitation hospitals, prosthetic service clinics, and accredited physical therapy programs. Each survey was designed to assess both limb loss/limb difference rehabilitation and prosthetic specific-content germane to the setting being surveyed. Results Sixty-eight physical therapy programs, 48 prosthetic-service providers, and 14 rehabilitation hospitals responded. Just over one third of physical therapy education programs reported having a course dedicated solely to prosthetic-related content. There was general alignment between what is being taught and what is being practiced in the clinics; however, there was variation in specific content and time devoted to prosthetic-related curriculum across programs. Conclusions Further alignment of prosthetic-related content and clinical practice is needed in physical therapy programs. Clinical Relevance Statement More careful alignment of prosthetic curricular content with clinical practice in physical therapy programs will increase the effectiveness of rehabilitation programs and help persons with amputations regain more function and quality of life.

Deep CNN with late fusion for real time multimodal emotion recognition

Emotion recognition is a fundamental aspect of human communication and plays a crucial role in various domains. This project aims at developing an efficient model for real-time multimodal emotion recognition in videos of human oration (opinion videos), where the speakers express their opinions about various topics. Four separate datasets contributing 20,000 samples for text, 1,440 for audio, 35,889 for images, and 3,879 videos for multimodal analysis respectively are used. One model is trained for each of the modalities: fastText for text analysis because of its efficiency, robustness to noise, and pre-trained embeddings; customized 1-D CNN for audio analysis using its translation invariance, hierarchical feature extraction, scalability, and generalization; custom 2-D CNN for image analysis because of its ability to capture local features and handle variations in image content. They are tested and combined on the CMU-MOSEI dataset using both bagging and stacking to find the most effective architecture. They are then used for real-time analysis of speeches. Each of the models is trained on 80% of the datasets, the remaining 20% is used for testing individual and combined accuracies in CMU-MOSEI. The emotions finally predicted by the architecture correspond to the six classes in the CMU-MOSEI dataset. This cross-dataset training and testing of the models makes them robust and efficient for general use, removes reliance on a specific domain or dataset, and adds more data points for model training. The proposed architecture was able to achieve an accuracy of 85.85% and an F1-score of 83 on the CMU-MOSEI dataset.

Effects of Fe and Cr on the microstructure and mechanical properties of FexCr72−xNi14Al14 high-entropy alloys

Cobalt-free lightweight FexCr(72−x)Ni14Al14 (x = 34, 36; at%) high-entropy alloys were designed and prepared in this study to determine the effects of Fe and Cr content variations on the microstructure and mechanical properties of the alloys. Both alloys were prepared from pure metals using a vacuum arc melting furnace. The microstructures of the alloys were characterized using various analytical methods and the macroscopic compressive mechanical properties and microscopic creep properties were investigated. Both alloys were composed of a disordered α(Fe-Cr) body-centered cubic matrix and ordered (Ni-Al) B2 nanoparticle precipitates, with the differently sized nanoparticle precipitates and micron grains forming a four-stage layered structure. The alloys exhibited excellent compressive properties with a maximum yield strength of 1378 MPa, compression ratio of 34.1 %, and high specific yield strength of 210 kPa·m3/kg. Dense geometrically necessary dislocations (GNDs) were observed in the grains of the two as-cast alloys. GND was the main deformation mechanism in the early stages of creep, and the GNDs and B2 precipitated phase became obstacles to dislocation movement, which improved the creep resistance of the alloys. Excellent mechanical properties and good economy have great attraction in structural materials

Impact of Variation in Amylose Content on Durum Wheat cv. Svevo Technological and Starch Properties.

Reserve starch, the main component of durum wheat semolina, is constituted of two glucan homopolymers (amylose and amylopectin) that differ in their chemical structure. Amylose is mainly a linear structure formed of α-1,4-linked glucose units, with a lower polymerization degree, whereas amylopectin is a highly branched structure of α-1,4-chains linked by α-1,6-bonds. Variation of the amylose/amylopectin ratio has a profound effect on the starch properties which may impact the wheat technological and nutritional characteristics and their possible use in the food and non-food sector. In this work a set of genotypes, with a range of amylose from 14.9 to 57.8%, derived from the durum wheat cv. Svevo was characterised at biochemical and rheological level and used to produce pasta to better understand the role of amylose content in a common genetic background. A negative correlation was observed between amylose content and semolina swelling power, starch peak viscosity, and pasta stickiness. A worsening of the firmness was observed in the low amylose pasta compared to the control (cv. Svevo), whereas no difference was highlighted in the high amylose samples. The resistant starch was higher in the high amylose (HA) pasta compared to the control and low amylose (LA) pasta. Noteworthy, the extent of starch digestion was reduced in the HA pasta while the LA genotypes offered a higher starch digestion, suggesting other possible applications.

East African highland cooking banana: towards an efficient selection of hybrids with user-preferred food quality traits.

Determinants of culinary qualities of East African highland cooking bananas (EAHCB) are not well known. This constrains the inclusion of user-preferred traits in breeding. The present study aimed to quantify key indicators of user-preferred characteristics to enable selection of acceptable hybrids. Qualitative characteristics that drive preference were big bunches (15-34 kg), long straight/slightly curved fingers (12-23 cm), yellowness and soft texture. Descriptive sensory analysis of the intensity of colour and texture the 23 genotypes revealed that landraces Kibuzi, Mbwazirume, Nakitembe and Mpologoma had higher intensity of yellowness and lower intensity of hardness (softer) and a low score (≤ 1.0) of astringency taste. A preference test showed that they had higher acceptability scores. Biochemical, instrumental and sensory data revealed correlations between sensory firmness and instrumental hardness (r = 0.5), sensory firmness and amylopectin (r = -0.54), suggesting that qualitative descriptions can be predicted by instrumental and biochemical indicators. Significant (P < 0.05) variations in amylose and total starch content were observed in different varieties. Moderate correlations between instrumental hardness and firmness in mouth (r = 0.55), cohesiveness and firmness in the mouth (r = 0.57), and adhesiveness and firmness in the mouth (r = 0.64) were observed. Surprisingly, carotenoids content was not correlated with yellowness in cooked matooke. However, positive correlations were observed between chroma (b*) parameters of raw matooke and sensorial assessed color on cooked samples. Qualitative characteristis; the bunch, pulp colour and texture; that drive users-preference in the EAHCB were quantified, paving way for breeders to use them to select genotypes with these attributes early in the breeding process. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Deciphering the Effect of Microstructural Modification in Sodium Alginate-Based Solid Polymer Electrolyte by Unlike Anions.

Microstructure modification in sodium alginate (NaAlg)-based solid polymer electrolytes by the perchlorate (ClO4-) and acetate (CH3COO-) anions of sodium salts has been reported. ClO4- participates in the structure-breaking effect via inter/intramolecular hydrogen bond breaking, while CH3COO- changes the amorphous phase, as evident from X-ray diffraction studies. The larger size and negative charge delocalization of ClO4- have a plasticizing effect, resulting in a lower glass transition temperature (Tg) compared to CH3COO-. Decomposition temperature is strongly dependent on the type of anion. Scanning electron microscopy images showed divergent modifications in the surface morphology in both electrolyte systems, with variations in salt content. The mechanical properties of the NaAlg-NaClO4 electrolyte systems are better than those of the NaAlg-CH3 COONa system, indicating weak interactions in the latter. Although most of the studies focus on the cation influence on conductivity, the interaction of the anion and its size certainly have an influence on the properties of solid polymer electrolytes, which will be of interest in the near future for sodium ion-based electrolytes in energy storage devices.

Structures and electrochemical performances of La0.7Sm0.3MgNi3·6Co0.4 + xwt.%Ni (x = 0,5,10,15,20) alloys applied to Ni-MH battery

The La–Mg–Ni–Co-based AB2-type alloys, namely La0.7Sm0.3MgNi3·6Co0.4xwt.%Ni (x = 0,5,10, 15, 20), were synthesized through ball milling. The study focused on investigating the impact of Ni content on the structures and electrochemical properties. The structures of the samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Transmission electron microscope (TEM). It has been demonstrated that the experimental samples consist of a primary phase, LaMgNi4, and a secondary phase, LaNi5. The abundance of phases undergoes significant changes with variations in Ni content, while the phase composition remains constant. The results indicate that a rise in Ni concentration results in an elevation of the LaNi5 phase and a reduction of the LaMgNi4 phase. Additionally, ball milling and the addition of nickel contribute to the refinement of the alloy grains. As the nickel concentration reached 20 wt%, the cycle retention rate(S30) of the composite alloy electrode achieved its maximum value of 73.42 %. In addition, the electrochemical kinetic test findings demonstrated that the maximum D value of the hydrogen diffusion system was 1.807 × 10−10 cm2/s and that the maximum current density of the composite hydrogen storage alloy electrode was 723 mA/g when x = 0 wt%.

Time-step constraints in coupled hydro-mechanical finite element analysis of unsaturated soils

In the finite element (FE) modelling of transient coupled problems for soils, the associated equations need to be integrated numerically over a time interval during the solution process. A minimum time-step size has been observed to exist, below which spatial oscillations in the obtained solutions can occur. These oscillations might lead to an accumulation of the resultant errors, eventually leading to invalid final predictions. This paper presents an analytical approach for deriving the time-step constraints for FE modelling of the transient behaviour of unsaturated soils with a fully coupled hydro-mechanical (HM) formulation. The effects of both element type and nonlinear soil properties are accounted for in the derivation. The proposed time-step constraints were subsequently verified through a series of coupled HM FE analyses of unsaturated soils, showing an excellent agreement. The present work shows that, when dealing with unsaturated soils, the minimum time-step size depends on the suction range investigated. This dependency derives from the nonlinear variation of water content and permeability with suction, as demonstrated through a set of comparative studies with three different types of unsaturated clays.

Holistic multiphysics simulation of climatic responses of cold region pavements

In cold regions, the environment dynamics lead to variations of soil temperature, water content, and deformation, which are characterized by highly coupled physical interplay. The hydraulic and thermal properties of unsaturated soils are highly nonlinear, which is further complicated when subjected to freezing. This paper presents a comprehensive multiphysics coupling model to evaluate these complex processes. The model considers the behaviors of unsaturated frozen soils. It accounts for the influences of meteorological, geothermal, and hydrological factors. The model is validated through two pavement case studies using Long-Term Pavement Performance (LTPP) road section data. The first case analysis is performed for a pavement section in Vermont, and the simulation lasted for 30 days during a non-freezing season on an hourly basis. The results validated the performance of the model considering unsaturated soil behaviors. The second case study is based on a daily analysis of a pavement section in South Dakota over a freezing–thawing cycle over 194 days. The results validated the model in considering the frozen unsaturated soil behaviors. Both case studies demonstrate the performance of this comprehensive model in quantifying the spatial and temporal variations of soil temperature and water content in response to environmental stressors. The capability of the model in accurately predicting the responses of pavement to the meteorological factors unleashes the potential of this model to assess the effects of climate and climate change on cold region pavement, as well as other types of geo-structures.

Green Ultrasound-Assisted Extraction of Podophyllotoxin from Juniperus scopulorum Needles

Background—Podophyllotoxin, a polyphenolic compound with major applications in cancer treatment, is in short supply, as its source is now an endangered plant species. It is therefore essential to find another available plant that produces high levels of podophyllotoxin. Some Juniperus species are known to contain podophyllotoxin, more exactly within their needles, but are still unused in this regard. Objective—The aim is to develop an efficient green ultrasound-assisted extraction protocol for podophyllotoxin from commercially available Juniperus scopulorum varieties. Methodology—To highlight optimal extraction conditions, a single-factor experiment was performed to identify the parameters (extraction duration, frequency, temperature extraction, preliminary grinding, and plant material concentration) influencing extraction. A multifactorial approach using the Box–Behnken design was then applied to determine the exact optimal extraction conditions. Results—The conditions for extracting the maximum amount of podophyllotoxin consist of 51.5 min of extraction time, in ethanol at 69.3%, and at 58.8 °C. This is the highest podophyllotoxin extraction yield ever obtained from Juniperus scopulorum needles. Compared with the reference protocol for the extracting of podophyllotoxin from Juniperus, ultrasonic extraction is an eco-friendly protocol, safe for humans, and the podophyllotoxin extracted by this method has much greater stability, allowing its purification. The analyses also indicate a variation in the podophyllotoxin content of Juniperus scopulorum needles, (from 7.02 to 10.34 mg/g DW) depending on the variety and year of purchase. Conclusion—Extraction in ethanol at 69.3% and at 58.8 °C for 51.5 min allows the extraction of up to 10.34 mg podophyllotoxin/g from freeze-dried Juniperus scopulorum needles.