Soil moisture-based irrigation interval and irrigation performance evaluation: In the case of lower kulfo catchment, Ethiopia.

The lack of soil moisture-based irrigation intervals, poor distribution of irrigation water among users, and the time-based and spatial variability of water supply have been challenges for the productivity of irrigation schemes in the Lower Kulfo catchment, Southern Ethiopia. This study was conducted to develop soil moisture-based irrigation intervals and to evaluate irrigation water delivery and field level irrigation efficiencies. Soil water content, and flow along the canal and in the field were measured directly, and irrigation duty was estimated by using CropWat 8 model. To minimize water stress or excess problems, irrigation needs to be applied when soil water content drops to 35.7 % for onion and pepper, 34.4 %% for watermelon, and 32.5 % for wheat and maize from field capacity. However, irrigation was applied at 36.2 % for onion, 35.4 % for watermelon, 36.4 % for pepper, 36.2 % for maize, and 35 % for wheat in the existing irrigation scheme that increased irrigation amount in the field. The average percentage of soil moisture depletion (p) at time of irrigation was 27.4 %, which was below the recommended value. The average adopted irrigation and design irrigation interval were 4 & 6 days for onion and pepper, 5 & 7 days for watermelon and wheat, and 6 & 7 days for maize, respectively. The mean irrigation adequacy and dependability of the irrigation scheme in the lower Kulfo catchment were 1 & 0 for Arba Minch irrigation scheme, 0.5 & 0.2 for Arba Minch University farmland, 0.4 & 0.25 for private farmland and 0.1 & 0.43 for Kollashara farmland, respectively. The value of irrigation equity was 0.7 in January, 0.6 in February, and 0.8 in March which indicates the highly temporary variation of irrigation adequacy. The mean value of canal conveyance was 82.7 % and the average on-farm irrigation efficiency also was 56.6 %. The average value crop yield in the present study were 0.5ton/ha for wheat, 4.9ton/ha for onion, 6.2ton/ha for pepper, 0.6ton/ha for watermelon, 4.2ton/ha for maize that was very low compared with other control irrigation in the study area. Inadequate soil moisture-based intervals, inequitable water distribution, and variable supply hinder irrigation in the Lower Kulfo catchment; adopting optimized practices and robust management can enhance efficiency, equity, and crop productivity.

Spatiotemporal patterns of greenhouse gas fluxes in the subtropical wetland ecosystem of Indian Himalayan foothill.

The study characterized the temporal and spatial variability in greenhouse gas (GHG) fluxes (CO2, CH4, and N2O) between December 2020 and November 2021 and their regulating drivers in the subtropical wetland of the Indian Himalayan foothill. Five distinct habitats (M1-sloppy surface at swamp forest, M2-plain surface at swamp forest, M3-swamp surface with small grasses, M4-marshy land with dense macrophytes, and M5-marshy land with sparse macrophytes) were studied. We conducted in situ measurements of GHG fluxes, microclimate (AT, ST, and SMC(v/v)), and soil properties (pH, EC, N, P, K, and SOC) in triplicates in all the habitat types. Across the habitats, CO2, CH4, and N2O fluxes ranged from 125 to 536 mg m-2 h-1, 0.32 to 28.4 mg m-2 h-1, and 0.16 to 3.14 mg m-2 h-1, respectively. The habitats (M3 and M5) exhibited higher GHG fluxes than the others. The CH4 flux followed the summer > autumn > spring > winter hierarchy. However, CO2 and N2O fluxes followed the summer > spring > autumn > winter. CO2 fluxes were primarily governed by ST and SOC. However, CH4 and N2O fluxes were mainly regulated by ST and SMC(v/v) across the habitats. In the case of N2O fluxes, soil P and EC also played a crucial role across the habitats. AT was a universal driver controlling all GHG fluxes across the habitats. The results emphasize that long-term GHG flux monitoring in sub-tropical Himalayan Wetlands has become imperative to accurately predict the near-future GHG fluxes and their changing nature with the ongoing climate change.

Delineating groundwater potential zones using integrated remote sensing and GIS in Lahore, Pakistan.

Groundwater depletion and water scarcity are pressing issues in water-limited regions worldwide, including Pakistan, where it ranks as the third-largest user of groundwater. Lahore, Pakistan, grapples with severe groundwater depletion due to factors like population growth and increased agricultural land use. This study aims to address the lack of comprehensive groundwater availability data in Lahore's semi-arid region by employing GIS techniques and remote sensing data. Various parameters, including Land Use and Land Cover (LULC), Rainfall, Drainage Density (DD), Water Depth, Soil Type, Slope, Population Density, Road Density, Normalized Difference Vegetation Index (NDVI), Normalized Difference Built-Up Index (NDBI), Moisture Stress Index (MSI), Water Vegetation Water Index (WVWI), and Land Surface Temperature (LST), are considered. Thematic layers of these parameters are assigned different weights based on previous literature, reclassified, and superimposed in weighted overlay tool to develop a groundwater potential zones index map for Lahore. The groundwater recharge potential zones are categorized into five classes: Extremely Bad, Bad, Mediocre, Good, and Extremely Good. The groundwater potential zone index (GWPZI) map of Lahore reveals that the majority falls within the Bad to Mediocre recharge potential zones, covering 33% and 28% of the total land area in Lahore, respectively. Additionally, 14% of the total area falls under the category of Extremely Bad recharge potential zones, while Good to Extremely Good areas cover 19% and 6%, respectively. By providing policymakers and water supply authorities with valuable insights, this study underscores the significance of GIS techniques in groundwater management. Implementing the findings can aid in addressing Lahore's groundwater challenges and formulating sustainable water management strategies for the city's future.

Food Safety Research and Extension Needs for the U.S. Low-Moisture Food Industry.

Historically, low-moisture foods were considered to have minimal microbial risks. However, they have been linked to many high-profile multistate outbreaks and recalls in recent years, drawing research and extension attention to low-moisture food safety. Limited studies have assessed the food safety research and extension needs for the low-moisture food industry. The objectives of this needs assessment were to explore the food safety culture and education needs, identify the food safety challenges and data gaps, and understand the barriers to adopting food-safety-enhancing technologies in the U.S. low-moisture food industry. This needs assessment was composed of two studies. In Study 1, food safety experts from the low-moisture food industry upper management participated in online interviews and a debriefing discussion session. In Study 2, an online anonymous survey was disseminated to a different group of experts with experience in the low-moisture food industry. The qualitative data were analyzed using deductive and inductive coding approaches, while the quantitative data were analyzed via descriptive analysis. Twenty-five experts participated in the studies (Study 1: n=12; Study 2: n=13). Common commodities that participants had worked with included nuts and seeds, spices, flour, and dried fruits and vegetables. A food safety culture conceptual framework was adapted, which included three main components: infrastructure conditions (foundation), individual's food safety knowledge, attitudes, and risk perceptions; and organizational conditions (supporting pillars). Major barriers to establishing a positive food safety culture were identified to be limited resources, difficulties in risk communication, and difficulties in behavioral change. For continual improvement in food safety performance, two major themes of food safety challenges and data gaps were identified: cleaning, sanitation, and hygienic design; and pathogen reduction. Participants perceived the main barriers discouraging the low-moisture food industry from adopting food-safety-enhancing technologies were: (1) budgetary priorities, (2) operation constraints, (3) technology validation, (4) consumer acceptance, and (5) maintaining desired product characteristics such as quality and sensory functionality. The findings of this needs assessment provide guidance for the food industry, academia, and government agencies about the direction of future research and the development of targeted extension programs that might help improve food safety in the low-moisture food industry.

Influence of surface water and groundwater gradient on spatial distribution of typical vegetation in the hinterland of Taklamakan desert.

Water resources are essential for desert oases and are key drivers of local ecological processes critical to the growth of desert vegetation. In this study, the oasis in the hinterland of the Taklamakan Desert, China, was selected as the research subject. Using high-precision classification of oasis vegetation through machine learning, surface water within the oasis was identified and extracted from multi-year Landsat remote sensing data. The spatial distribution patterns of the main community-building species, Populus euphratica and Tamarix ramosissima, were studied under different moisture gradients using environmental covariates and measured groundwater depth to invert its spatial distribution and K-mean clustering to construct surface water and groundwater moisture gradients. The results indicated that the classification accuracy for the two species reached 0.917. Gradients 1-5 were used to categorize the water resources, dividing surface water and groundwater into five gradients. Gradient 3 exhibited the optimal moisture conditions, with a high surface water distribution frequency (0.017) and shallow groundwater depth (3.158 m), while Gradient 4 showed the least optimal moisture conditions, characterized by a low surface water distribution frequency (0.008) and deep groundwater depth (4.820 m). The water gradient decreased in the following order: Gradient 3 > Gradient 5 > Gradient 1 > Gradient 2 > Gradient 4. The optimum gradients for growth of P. euphratica and T. ramosissima were gradients 5, 1, and 2. The normalized vegetation index spatial distribution patterns of the two species were consistent with that of the moisture gradient. Tamarix ramosissima was found to be more tolerant to salinity and drought than P. euphratica. Overall, this study provides valuable information on the effect of the spatial distribution of water resource gradients on oasis vegetation and can guide future water delivery policies in oases.

Why does afforestation policy lead to a drying trend in soil moisture on the Loess Plateau?

Soil moisture is a key factor for vegetation restoration in arid and semi-arid regions. Clarifying the vertical characteristics of soil moisture in artificial forests on a regional scale and its response mechanisms can benefit for land use management in water-deficient areas such as the Loess Plateau. The study targets Robinia pseudoacacia on the Loess Plateau with a meta-analysis based on 790 soil moisture data points abstracted from 35 published papers. The results show that extensive cultivation of R pseudoacacia on the Loess Plateau leads to a significant reduction in soil moisture (P < 0.05). Soil moisture decreases significantly with growth of trees, especially between 400 and 500 cm soil layers. Soil moisture increases with the hydrothermal gradient. The results indicate that intensive afforestation activities in high temperature and rainy areas still significantly consume deep soil moisture. The main reason is that the impact of hydrothermal factors on soil moisture is significant between 0 and 200 cm soil layers and decreases with increasing soil depth. However, the continuous depletion of deep soil moisture leads to insignificant differences in soil moisture responses under different topographical conditions in the region. Therefore, neglecting the impact of forest age and hydrothermal factors on soil moisture in afforestation activities, the excessive water consumption by R pseudoacacia during growth poses potential risks to the ecological environment of the Loess Plateau. This study provides references for knowledge on water relating problems and sustainable management of artificial forests in arid and semi-arid areas.

Binding and distribution regularity of water molecules in high-moisture textured Antarctic krill (Euphausia superba) meat.

High-moisture extrusion technique with the advantage of high efficiency and low energy consumption is a promising strategy for processing Antarctic krill meat. Consequently, this study aimed to prepare high-moisture textured Antarctic krill meat (HMTAKM) with a rich fiber structure at different water contents (53 %, 57 %, and 61 %) and to reveal the binding and distribution regularity of water molecules, which is closely related to the fiber structure of HMTAKM and has been less studied. The hydrogen-bond network results indicated the presence of at least two or more types of water molecules with different hydrogen bonds. Increasing the water content of HMTAKM promoted the formation of hydrogen bonds between the water molecules and protein molecules, leading to the transition of the ß-sheet to the α-helix. These findings offer a novel viable processing technique for Antarctic krill and a new understanding of the fiber formation of high-moisture textured proteins.

Multi-source machine learning and spaceborne remote sensing data accurately predict three-dimensional soil moisture in an in-service uranium disposal cell.

One reason arid and semi-arid environments have been used to store waste is due to low groundwater recharge, presumably limiting the potential for meteoric water to mobilize and transport contaminants into groundwater. The U.S. Department of Energy Office of Legacy Management (LM) is evaluating selected uranium mill tailings disposal cell covers to be managed as evapotranspiration (ET) covers, where vegetation is used to naturally remove water from the cover profile via transpiration, further reducing deep percolation. An important parameter in monitoring the performance of ET covers is soil moisture (SM). If SM is too high, water may drain into tailings material, potentially transporting contaminants into groundwater; if SM is too low, radon flux may increase through the cover. However, monitoring SM via traditional instrumentation is invasive, expensive, and may fail to account for spatial heterogeneity, especially over vegetated disposal cells. Here we investigated the potential for non-invasive SM monitoring using radar remote sensing and other geospatial data to see if this approach could provide a practical, accurate, and spatially comprehensive tool to monitor SM. We used theoretical simulations to analyze the sensitivity of multi-frequency radar backscatter to SM at different depths of a field-scale (3 ha) drainage lysimeter embedded within an in-service LM disposal cell. We then evaluated a shallow and deep form of machine learning (ML) using Google Earth Engine to integrate multi-source observations and estimate the SM profile across six soil layers from depths of 0-2 m. The ML models were trained using in situ SM measurements from 2019 and validated using data from 2014 to 2018 and 2020-2021. Model predictors included backscatter observations from satellite synthetic aperture radar, vegetation, temperature products from optical infrared sensors, and accumulated, gridded rainfall data. The radar simulations confirmed that the lower frequencies (L- and P-band) and smaller incidence angles show better sensitivity to deeper soil layers and an overall larger SM dynamic range relative to the higher frequencies (C- and X-band). The ML models produced accurate SM estimates throughout the soil profile (r values from 0.75 to 0.94; RMSE = 0.003-0.017 cm3/cm3; bias = 0.00 cm3/cm3), with the simpler shallow-learning approach outperforming a selected deep-learning model. The ML models we developed provide an accurate, cost-effective tool for monitoring SM within ET covers that could be applied to other vegetated disposal cell covers, potentially including those with rock-armored covers.

The unique distribution pattern of PFAS in landfill organics.

PFAS from degrading landfill waste partition into organic matter, leachate, and landfill gas. Driven by the limited understanding of PFAS distribution in landfill organics, we analyzed PFAS across various depths and seven spatially distinct locations within a municipal landfill. The measured PFAS concentrations in organics ranged from 6.71 to 73.06 µg kg-1, a sum of twenty-nine PFAS from six classes. Perfluorocarboxylic acids (PFCAs) and fluorotelomer carboxylic acids (FTCAs) were the dominant classes, constituting 25-82 % and 8-40 % of total PFAS at different depths. PFBA was the most dominant PFCA with a concentration range of 0.90-37.91 µg kg-1, while 5:3 FTCA was the most prevalent FTCA with a concentration of 0.26-17.99 µg kg-1. A clear vertical distribution of PFAS was observed, with significantly greater PFAS concentrations at the middle depths (20-35 ft), compared to the shallow (10-20 ft) and high depths (35-50 ft). A strong positive correlation (r > 0.50) was noted between total PFAS, total carbon, and dissolved organic matter in landfill organics. Multivariate statistical analysis inferred common sources and transformations of PFAS within the landfill. This study underscores the importance of a system-level analysis of PFAS fate in landfills, considering waste variability, chemical properties, release mechanisms, and PFAS transformations.

Enhanced Corrosion Protection of Printed Circuit Board Electronics using Cold Atmospheric Plasma-Assisted SiOx Coatings.

The miniaturization and widespread deployment of electronic devices across diverse environments have heightened their vulnerability to corrosion, particularly affecting copper traces within printed circuit boards (PCBs). Conventional protective methods, such as conformal coatings, face challenges including the necessity for a critical thickness to ensure effective barrier properties and the requirement for multiple steps of drying and curing to eliminate solvent entrapment within polymer coatings. This study investigates cold atmospheric plasma (CAP) as an innovative technique for directly depositing ultrathin silicon oxide (SiOx) coatings onto copper surfaces to enhance corrosion protection in PCBs. A systematic investigation was undertaken to examine how the scanning speed of the CAP deposition head impacts the film quality and corrosion resistance. The research aims to determine the optimal scanning speed of the CAP deposition head that achieves complete surface coverage while promoting effective cross-linking and minimizing unreacted precursor entrapment, resulting in superior electrical barrier and mechanical properties. The CAP coating process demonstrated the capability of depositing SiOx onto copper surfaces at various thicknesses ranging from 70 to 1110 nm through a single deposition process by simply adjusting the scanning speed of the plasma head (5-75 mm/s). Evaluation of material corrosion barrier characteristics revealed that scanning speeds of 45 mm/s of the plasma deposition head provided an effective coating thickness of 140 nm, exhibiting superior corrosion resistance (30-fold) compared to that of uncoated copper. As a proof of concept, the efficacy of CAP-deposited SiOx coatings was demonstrated by protecting an LED circuit in saltwater and by coating printed circuits for potential agricultural sensor applications. These CAP-deposited coatings offer performance comparable to or superior to traditional conformal polymeric coatings. This research presents CAP-deposited SiOx coatings as a promising approach for effective and scalable corrosion protection in miniaturized electronics.

Production and characterization of coconut shell charcoal-based bio-briquettes as an alternative energy source for rural communities.

The increasing demand for sustainable energy solutions has driven interest in the utilization of agricultural residues, such as coconut shells, for bio-briquette production. This study investigates the impact of binder types (cassava and corn) and concentrations (5 wt%, 10 wt%, 15 wt%) on the properties of bio-briquettes made from dried coconut shells with two particle sizes (40 mesh and 60 mesh). The experimental evaluation focuses on several performance indicators, including density, shatter index, percentage moisture content (PMC), percentage volatile matter (PVM), percentage ash content (PAC), percentage fixed carbon (PFC), higher heating value (HHV), ignition time, burning time, and boiling time. The results indicate that briquettes with 10 % fine charcoal cassava binder achieved the highest density of 0.764 g/cm³ due to improved compaction. Briquettes with 15 % coarse charcoal corn binder demonstrated the highest shatter resistance at 96.99 %, reflecting their superior structural integrity. The highest PMC and PVM values were observed in briquettes with 15 % coarse charcoal cassava binder, at 8.13 % and 31.25 %, respectively. Conversely, the highest PAC was 16.34 % for 5 % coarse charcoal cassava binder. Briquettes with 10 % fine charcoal corn binder exhibited the highest PFC of 70.79 % and HHV of 31.51 MJ/kg. Boiling times ranged from 15 min 53 s to 36 min 35 s, with the shortest boiling time for briquettes with 10 % fine charcoal corn binder. The findings highlight the superior mechanical properties and energy performance of bio-briquettes with specific binder concentrations and particle sizes. This study demonstrates the potential of coconut shell bio-briquettes as a viable and sustainable energy source, offering economic and environmental benefits through the effective utilization of agricultural waste and reduction of carbon emissions.

Recent advances in moisture-induced electricity generation based on wood lignocellulose: Preparation, properties, and applications.

Moisture-induced electricity generation (MEG), which can directly harvest electricity from moisture, is considered as an effective strategy for alleviating the growing energy crisis. Recently, tremendous efforts have been devoted to developing MEG active materials from wood lignocellulose (WLC) due to its excellent properties including environmental friendliness, sustainability, and biodegradability. This review comprehensively summarizes the recent advances in MEG based on WLC (wood, cellulose, lignin, and woody biochar), covering its principles, preparation, performances, and applications. In detail, the basic working mechanisms of MEG are discussed, and the natural features of WLC and their significant advantages in the fabrication of MEG active materials are emphasized. Furthermore, the recent advances in WLC-based MEG for harvesting electrical energy from moisture are specifically discussed, together with their potential applications (sensors and power sources). Finally, the main challenges of current WLC-based MEG are presented, as well as the potential solutions or directions to develop highly efficient MEG from WLC.

Data from the experiment of dynamic moisture transport in spruce wood under cyclic step-changes in relative humidity 72-95.

The interaction of wood and moisture has to be considered in many industrial sectors. Wood is highly hygroscopic material while the absorbed moisture affects all its technical properties. One of them is a moisture permeability which is further affected by the sorption hysteresis and also differs in the three wood anatomical directions - radial, tangential, and axial. For the prediction of the dynamic hygro-thermal behaviour of wood can be used numerical simulation tools. However, data from carefully designed and controlled experiments are needed for reliable validation of these tools. This paper presents data from a 45-day dynamic laboratory experiment. The one-dimensional moisture transport in spruce wood in the tangential and radial directions under isothermal conditions was studied. The samples were exposed to cyclic step-changes in relative humidity 72-95 % at 23 °C. Data show the rate of stabilisation of moisture content in the samples, the effect of sorption hysteresis, and changes in the temperature of samples due to moisture sorption. In addition, the paper also presents material functions describing the sorption properties and moisture permeability of spruce wood. These properties were determined based on laboratory measurements using the spruce wood of the same origin as used for the dynamic experiment. The dynamic data, together with the proposed material functions can be used in the development or verification of hygro-thermal numerical simulation tools.

Soil moisture-dependent tire wear particles aging processes shift soil microbial communities and elevated nitrous oxide emission on drylands.

Tire wear particles (TWPs) have been an emerging threat to the soil ecosystem, while impact of the TWPs aging on soil microbial communities remains poorly understood. This study investigated the dynamic responses of soil microbial communities to the TWPs aging under both wet and flooded conditions. We found that different soil moisture conditions resulted in distinct microbial community structures. Soil bacteria were more sensitive to wet conditions, while soil fungi were more sensitive to flooded conditions. The family Symbiobacteraceae was predominant in the TWP-sphere under both wet and flooded conditions after 60 days, followed by Brevibacillaceae. Notably, we observed that TWPs input significantly increased nitrous oxide (N2O) emission from dryland soil. Several taxa including Cyanobacteriales, Blastocatellaceae and Pyrinomonadaceae were identified as TWP-biomarkers in soils and potentially played significant roles in N2O emissions from drylands. Their responses to the TWPs input correlated closely with changes in the relative abundance of genes involved in ammonia oxidation (amoA/B), nitrite reduction (nirS/K) and N2O reduction (nosZ) in drylands. Our results demonstrate that soil moisture-dependent TWP aging influences N2O emission by altering both the associated microbial communities and the relevant genes.

Temporal changes in net ecosystem CO2 exchange and influential factors in an apple orchard in Northeast China.

The apple orchards in Liaoning, one of the four major apple-producing areas in Bohai Bay, Northeast China, play a crucial role in regulating the carbon sink effect. However, there is limited information on the variation in carbon flux and its influential factors in apple orchards in this region. To address this, CO2 flux data were monitored throughout the entire apple growth seasons from April to November in 2017 and 2018 in the apple (Malus pumila Mill. cv Hanfu) orchard in Shenyang, China. The energy closure of the apple orchard was calculated, and variations in net ecosystem exchange (NEE) at different time scales and its response to environmental factors were analyzed. Our results showed that the energy balance ratio of the apple was 0.74 in 2017 and 1.38 in 2018. NEE was generally positive in April and November and negative from May to October, indicating a strong carbon sink throughout the growth season. The daily average NEE ranged from - 0.103 to 0.094 mg m-2 s-1 in 2017 and from - 0.134 to 0.059 mg m-2 s-1 in 2018, with the lowest values observed in June and July. NEE was negatively correlated with net radiation, atmospheric temperature, saturated vapor pressure deficit, and soil temperature. These findings provide valuable insights for predicting carbon flux in orchard ecosystems within the context of global climate change.

Moisture Impact on Static and Dynamic Modulus of Elasticity in Structural Normal-Weight Concretes.

In the case of concrete built into a structure, the static secant modulus of elasticity (Ec,s) is often estimated based on its dynamic value (Ed) measured by the ultrasonic pulse velocity method instead of direct tests carried out on drilled cores. Meanwhile, the prevailing equations applied to estimate Ec,s often overlook the impact of concrete moisture. This study aimed to elucidate the moisture impact across two normal-weight structural concretes differing in compressive strength (51.6 and 71.4 MPa). The impact of moisture content was notably more evident only for the weaker concrete, according to dynamic modulus measurements. In other cases, contrary to the literature reports and expectations, this effect turned out to be insignificant. These observations may be explained by two factors: the relatively dense and homogeneous structure of tested concretes and reduced sensitivity of Ec,s measurements to concrete moisture condition compared to Ed measurements obtained using the ultrasonic method. Additionally, established formulas to estimate Ec,s were verified. The obtained modulus results tested under different moisture conditions of normal-weight concretes were also compared with those of lightweight aggregate concretes of identical volume compositions previously obtained in a separate study.

A Study of the Effects of Moisture on Composite-to-Metal Double-Lap Shear Joints.

This work investigated the effects of moisture absorption treatment on composite-to-metal double-lap shear joints (DLSJs) bonded with epoxy adhesive film through experiments and simulations. The composite-to-metal DLSJ can be divided into five parts (the interface between the composite and adhesive, the interface between the adhesive and metal, the composite adherend, the metal adherend, and the adhesive layer). First, the wet-dependent properties of the adhesive and interfaces were obtained through adhesive tensile tests and GC tests, which showed that the properties of the adhesive and interfaces were significantly affected by the moist environment. Then, tensile tests of the composite-to-metal double-lap shear joints were carried out in dry and wet environments. Finally, based on the experimental investigations, a finite element (FE) model that considered cohesive damage was established for simulating damage evolution and predicting the failure loads and failure modes of the DLSJs. The results of both the experimental and numerical tests show that the DLSJ failure load decreases significantly after immersion in 95 °C water, and the major failure mode transfers from adhesive failure to interface failure. The research results provide a theoretical basis or basic data for the structural design of adhesively bonded composite-to-metal.

Influence of Montmorillonite Organoclay Fillers on Hygrothermal Response of Pultruded E-Glass/Vinylester Composites.

Pultruded fiber reinforced polymer composites used in civil, power, and offshore/marine applications use fillers as resin extenders and for process efficiency. Although the primary use of fillers is in the form of an extender and processing aid, the appropriate selection of filler can result in enhancing mechanical performance characteristics, durability, and multifunctionality. This is of special interest in structural and high voltage applications where the previous use of specific fillers has been at levels that are too low to provide these enhancements. This study investigates the use of montmorillonite organoclay fillers of three different particle sizes as substitutes for conventional CaCO3 fillers with the intent of enhancing mechanical performance and hygrothermal durability. The study investigates moisture uptake and kinetics and reveals that uptake is well described by a two-stage process that incorporates both a diffusion dominated initial phase and a second slower phase representing relaxation and deterioration. The incorporation of the organoclay particles substantially decreases uptake levels in comparison to the use of CaCO3 fillers while also enhancing stage I, diffusion, dominated stability, with the use of the 1.5 mm organoclay fillers showing as much as a 41.5% reduction in peak uptake as compared to the CaCO3 fillers at the same 20% loading level (by weight of resin). The mechanical performance was characterized using tension, flexure, and short beam shear tests. The organoclay fillers showed a significant improvement in each, albeit with differences due to particle size. Overall, the best performance after exposure to four different temperatures of immersion in deionized water was shown by the 4.8 mm organoclay filler-based E-glass/vinylester composite system, which was the only one to have less than a 50% deterioration over all characteristics after immersion for a year in deionized water at the highest temperature investigated (70 °C). The fillers not only enhance resistance to uptake but also increase tortuosity in the path, thereby decreasing the overall effect of uptake. The observations demonstrate that the use of the exfoliated organoclay particles with intercalation, which have been previously used in very low amounts, and which are known to be beneficial in relation to enhanced thermal stability, flame retardancy, and decreased flammability, provide enhanced mechanical characteristics, decreased moisture uptake, and increased hygrothermal durability when used at particle loading levels comparable to those of conventional fillers, suggesting that these novel systems could be considered for critical structural applications.

Forest plant indicator values for moisture reflect atmospheric vapour pressure deficit rather than soil water content.

Soil moisture shapes ecological patterns and processes, but it is difficult to continuously measure soil moisture variability across the landscape. To overcome these limitations, soil moisture is often bioindicated using community-weighted means of the Ellenberg indicator values of vascular plant species. However, the ecology and distribution of plant species reflect soil water supply as well as atmospheric water demand. Therefore, we hypothesized that Ellenberg moisture values can also reflect atmospheric water demand expressed as a vapour pressure deficit (VPD). To test this hypothesis, we disentangled the relationships among soil water content, atmospheric vapour pressure deficit, and Ellenberg moisture values in the understory plant communities of temperate broadleaved forests in central Europe. Ellenberg moisture values reflected atmospheric VPD rather than soil water content consistently across local, landscape, and regional spatial scales, regardless of vegetation plot size, depth as well as method of soil moisture measurement. Using in situ microclimate measurements, we discovered that forest plant indicator values for moisture reflect an atmospheric VPD rather than soil water content. Many ecological patterns and processes correlated with Ellenberg moisture values and previously attributed to soil water supply are thus more likely driven by atmospheric water demand.

Developing an integrated model relating substrate water content to indoor temperature reduction for irrigation-decision support of a green roof.

This study analyzes the influences of evapotranspiration or substrate moisture variation on the indoor-temperature reduction of green roofs compared to the control group. A multiple linear regression (MLR) model for the operation stage based on observation and an integrated MLR model for the planning stage based on simulation are verified. The MLR model shows 0.64 °C of the Root Mean Square Error (RMSE) in predicting the hourly difference of temperature reduction based on the measured change in evapotranspiration and air temperature. The contributions of the hourly increment of air temperature (ΔTa) and increment of evapotranspiration (ΔET) are similar to the hourly increment of temperature reduction (ΔTdif). Then, the feasibility of the integrated MLR model is demonstrated based on the evapotranspiration and substrate moisture of a green roof simulated by a hydrological model as well as the indoor-temperature reduction simulated by a building energy model, which has fair performances in capturing the heat-transfer and water-balance physical process within a green roof. The integrated MLR model shows that evapotranspiration is relatively essential, followed by substrate moisture, air temperature, and vapor pressure. Despite the modeling bias, the integrated model quantitatively relates the influential factors to temperature reduction and predicts temperature reduction with an RMSE of 1.02 °C. The integrated model can quantify the influence of irrigation on temperature reduction under various climate conditions and green roof structures. This study demonstrates the procedure of establishing the integrated model. It shows the potential of the integrated model to provide decision support on irrigation for multi-purpose optimization of green roof performances.