High Moisture Content Research Articles

Macroscopic and mesoscopic mechanism of hydration instability of the rock-grout coupled structure

In order to investigate the macroscopic and mesoscopic mechanism of hydration instability of rock-grout structure under the influence of moisture content, a direct shear test combined with particle flow code (PFC) simulation was conducted subject to various moisture content levels and normal stresses. The results show that a higher moisture content would compromise the load bearing capacity of soft rock anchorage structures by deteriorating the structural integrity of the surrounding rock and the bonding effect between the anchorage interfaces. The load bearing capacity of the surrounding rock is also rapidly reduced. The rock-grout structure has four main shear damage modes, which are influenced by both moisture content and normal stress. When the saturated moisture content is reached, the anchorage structure has lost its bearing capacity, and the rock is muddied and subsequently debonded from the bolt. The energy required to break the internal adhesion of the rock-grout structure under the effect of hydration is greatly reduced, resulting in easy decoupling and dispersion between the rock skeleton particles. In turn, the rock surface particles bonded by the anchor agent are separated from the deeper particles, resulting in the failure of the bonding surface and weakening the coupling effect between the anchor and the surrounding rock. According to the test results, the control measures for surrounding rock of muddy roadway are put forward.

Effect of A Moringa Oil–Beeswax Edible Coating on the Shelf-Life and Quality of Fresh Cucumber

Cucumbers are a popular vegetable consumed worldwide and are known for their nutritional value, containing carbohydrates, antioxidants, vitamin C, etc. The abundance of a high moisture content is correlated to cucumber perishability, which encourages investigation into ways to maintain its quality and increase shelf-life. This study was carried out to determine the effect of a moringa oil–beeswax coating on the quality of fresh cucumber at different storage temperatures for 27 days of storage. Freshly harvested cucumbers were divided into two groups: the first group was coated with the moringa oil–beeswax edible coating, while the other one was not coated (control). Each group was divided into three other subgroups, for storage at 4, 10, and 22 °C. Different quality parameters, including weight loss, color change, firmness, total soluble solid (TSS), vitamin C, and pH, were evaluated. The findings showed that the weight loss of cucumber was highly increased in non-coated samples stored at high temperature. After 27 days of storage, the highest and lowest weight reduction % were recorded for non-coated cucumbers stored at 22 °C (38.09%) and moringa oil–beeswax-coated cucumbers stored at 10 °C (12.35%), respectively. Color analysis revealed that coating had a significant impact on color values, with distinct patterns in lightness, redness-greenness, and yellowness values for both treatments at various temperatures and days. The lightness values showed minimal fluctuations and stabilized at 13.65 at both 4 °C and 10 °C. Temperature and coating had a significant impact on pH levels, with the coating potentially exhibiting a protective effect on pH stability, particularly at lower temperatures (4 °C). Additionally, both groups’ total acidity levels held steady over time and at various temperatures, with the coating having a highly significant effect on total acidity levels. The amount of vitamin C varied significantly with temperature and storage period, but the coating did not affect vitamin C content. At 22 °C, there were notable variations in the vitamin C content over the storage period, with a final value of 37.7 mg/L on coated samples. Temperature and the duration of storage (p < 0.05) had a significant impact on the levels of total soluble solids (TSS), whereas firmness values changed significantly over the storage period only. Moringa oil–beeswax edible coating has the potential to preserve the nutritional value and quality attributes of cucumber.

Energetic, Exergetic, and Techno-Economic Analysis of A Bioenergy with Carbon Capture and Utilization Process via Integrated Torrefaction–CLC–Methanation

Bioenergy with carbon capture and storage (BECCS) or utilization (BECCU) allows net zero or negative carbon emissions and can be a breakthrough technology for climate change mitigation. This work consists of an energetic, exergetic, and economic analysis of an integrated process based on chemical looping combustion of solar-torrefied agro-industrial residues, followed by methanation of the concentrated CO2 stream with green H2. Four agro-industrial residues and four Italian site locations are considered. Depending on the considered biomass, the integrated plant processes about 18–93 kg h−1 of raw biomass and produces 55–70 t y−1 of synthetic methane. Global exergetic efficiencies ranged within 45–60% and 67–77% when neglecting and considering, respectively, the valorization of torgas. Sugar beet pulp and grape marc required a non-negligible input exergy flow for the torrefaction, due to the high moisture content of the raw biomasses. However, for these biomasses, the water released during drying/torrefaction and CO2 methanation could be recycled to the electrolyzer to eliminate external water consumption, thus allowing for a more sustainable use of water resources. For olive stones and hemp hurd, this water recycling brings, instead, a reduction of approximately 65% in water needs. A round-trip electric efficiency of 28% was estimated assuming an electric conversion efficiency of 40%. According to the economic analysis, the total plant costs ranged within 3–5 M€ depending on the biomass and site location considered. The levelized cost of methane (LCOM) ranged within 4.3–8.9 € kgCH4−1 but, if implementing strategies to avoid the use of a large temporary H2 storage vessel, can be decreased to 2.6–5.3 € kgCH4−1. Lower values are obtained when considering hemp hurd and grape marc as raw biomasses, and when locating the PV field in the south of Italy. Even in the best scenario, values of LCOM are out of the market if compared to current natural gas prices, but they might become competitive with the introduction of a carbon tax or through government incentives for the purchase of the PV field and/or electrolyzer.

An evaluation on the shrinkage deformation characteristics of Chinese yam during multiphase microwave drying based on digital image processing

The deformation characteristics of Chinese yam during multiphase microwave drying (MMD) was evaluated by image processing, and the effects of MMD on the drying characteristics, physical properties, shrinkage behavior, and microstructure of the samples were also investigated. The drying time was significantly reduced by increasing microwave power density. Compared with Scheme I, the time of Scheme V was shortened by 22.22%. The moisture content at the transition point from sublimation to evaporation drying stages (TPS-E) significantly affected the shrinkage of the samples. In Scheme I, the lowest moisture content at TPS-E of 0.354 g. g−1 was found, and the dried products with the shrinkage ratio and bulk density closest to those of FD. The deformation of Chinese yam mainly appeared in the evaporation drying stage. At this stage, the rate of change in cross-sectional area of dried samples ranged from 9.74% to 26.76% for Schemes II to Scheme V, compared to 2.03% for Scheme I. Similarly, the shrinkage ratio of the dried samples in Schemes II, III, IV, and V increased from 16.82% to 21.12% at TPS-E to 29.23% to 51.28% at the end of drying, respectively. Additionally, the shrinkage caused by the pores collapse of the samples because of the high moisture content at TPS-E (Scheme III, IV, and V) during the evaporation drying stage resulted in increases of bulk density. The present study can provide valuable insights for rational control of shrinkage and deformation of fruits and vegetables in MMD. Industrial relevanceChinese yam is a widely used food and medicinal resource in China due to its rich nutritional and medicinal values. Since the moisture content of Chinese yam can reach as high as 70–80%, drying serves as an effective method to broaden its application. However, shrinkage and deformation of materials during drying are common forms of appearance deterioration that can directly impact consumer acceptability. MMD has proven to be a promising drying technology. Nevertheless, improper drying parameter settings may lead to a deterioration of the appearance quality of MMD products. Therefore, comprehending the information of shrinkage and deformation of Chinese yam during MMD and effectively regulating these processes is essential. Mastering these aspects is critical for enhancing the economic value and consumer acceptance of dried Chinese yam products.

Analysis on Chemical and Physical Properties of Dried Sago Bagasse

The uncontrollable of sago bagasse waste from sago industry production become an environmental issue as it just dumping directly into nearby rivers which can affect a river pollution if not treated well. As it still has about 70% starch content, it has a potential to be converted to the others value-added product such as animal feed. However, before it can be converted to others product, it should go through a drying process to reduce its higher moisture content (90 wt.%), as well to prevent any micro bacteria growth and for long lasting packaging. Thus, this study focused on the evaluation of drying process at T=70 and 80 °C on reducing of its final moisture content by using three drying approaches: fluidized bed dryer (FBD), micro-oven and direct sunlight drying. Then, these samples of dried sago were analysed to determine its properties of starch, fibre, and ash, as well to study its functional organic chemical group by using Fourier infrared transform (FTIR) method. The results show the reduction of sago water content by FBD shown a significant result as compared to others drying methods as the FBD method produces a good solid mixed between particles. Besides, the drying rate using the FBD was achieved in a shorter time within 30 min as compared to oven which within 2 hours and sunlight drying within 6 days to achieve similar final desired moisture content at 11 wt.%. The analysis on the starch properties using the FBD was also almost 75% more higher than oven, which is about 70% starch content. Moreover, the presence of starch was successful proven by the presence of acrylic acid at a wavelength of 1539.72 cm-1 for FBD sample by using FTIR. In addition, using the FBD, the sago waste can maintain its quality as an animal feed by reached a brightness level, W1 as compared to the slurry sago waste where the dried sago using FBD is 58.78%, meanwhile the fresh slurry sago waste is 93.31%. In conclusion, the sago drying in the FBD at T=80 °C was selected as the optimum drying condition as it had achieved a short drying rate for desired final 11 wt.% moisture content and resulted in better on the chemical and physical analysis.

Research progress of mushroom drying pretreatment technology

AbstractMushrooms are delicious foodstuffs that are rich in nutrients, but they have high moisture contents and are easily spoiled. While mushrooms are usually preserved by drying, the process tends to reduce quality, and it takes a long time and consumes a large amount of energy. To improve the mushroom drying efficiency and quality, pretreatment is often conducted. In this review, a comprehensive summary of commonly used pretreatments for mushroom drying is provided. Moreover, the effects of various pretreatments on the drying rate and quality characteristics of mushrooms are summarized, and their respective advantages and limitations are analyzed. Furthermore, the application and development prospects of various mushroom drying pretreatments are analyzed and discussed.Practical applicationsThe pretreatment before mushroom drying can shorten drying time, maintain the optimal color and taste of dried mushroom, and reduce nutrient loss. This review summarizes two types of pretreatment methods used in mushroom drying: thermal pretreatment and nonthermal pretreatment. It can provide reference for the application and research of pretreatment in mushroom drying, and also provide new ideas for the optimization of industrial mushroom drying processes.

Fresh-Keeping Effect of Vacuum Skin Packaging on Whiteleg Shrimp (Penaeus vannamei)

ABSTRACT Penaeus vannamei (P. vannamei) is prone to deterioration and spoilage during storage due to its high content of moisture, amino acids, and protein. In order to prolong fresh-keeping state of P. vannamei products, the effects of vacuum skin packaging (VSP) and polyethylene (PE) packaging on the characteristics of P. vannamei stored at 4°C and −18°C were compared. Compared with P. vannamei with PE packaging, the values of physicochemical indexes during the late storage period were significantly lower compared to meat submitted to VSP technology (p < 0.05), with significantly higher scores in muscle chewiness and sensory attributes (p < 0.05). Moreover, VSP delayed the decrease in the content of α-helix in protein secondary structure during storage of P. vannamei at 4°C. VSP combined with low-temperature storage exhibited a more remarkable effect on ensuring fresh-keeping state of P. vannamei. In particular, the fresh-keeping state of P. vannamei stored at 4°C and −18°C was prolonged for two days and fifteen days, respectively, in VSP. Thus, VSP was shown to effectively prolong the shelf-life and increase the appearance of shrimp products, thus having a prospect for market application in their preservation and distribution.

A Meta-Analysis to Evaluate the Reliability of Depth-to-Water Maps in Predicting Areas Particularly Sensitive to Machinery-Induced Soil Disturbance

The careful planning of the extraction routes is one of the most important best management practices to limit soil disturbance related to ground-based forest operations. Over the recent years, this task has been commonly addressed in the framework of boreal forestry, by developing soil trafficability maps based on the depth-to-water (DTW) topographic index. The basic concept of trafficability maps developed with the DTW index is that soils at low DTW index, namely &amp;lt;1, could be more prone to soil compaction and rutting as they tend to have higher moisture content. However, previous studies that tried to assess the reliability of these maps reported contrasting results. Therefore, the present meta-analysis was developed to evaluate if soils at low DTW index (≤1) are actually more sensitive to soil compaction and rutting than soils at higher DTW index (&amp;gt;1). A database was created containing all the studies that assessed soil compaction and rutting in soils at low DTW index (experimental treatment) and high DTW index (control treatment), and a multivariate meta-analysis was used to check the presence of statistically significant effect size. Then the influence on the effect size of variables like soil texture, number of machine passage and weight of the machine, was checked by applying sub-group meta-analysis and meta-regression. Finally, a sensitivity analysis was performed by removing possible outliers from the database and repeating the analyses. No statistical differences were found in soil compaction and rutting severity in areas at low DTW index in comparison to the control areas (DTW index ≥1). The results showed that soil texture, number of machine passage and weight of the machine did not have a significant influence on the effect size. The sensitivity analysis developed after removing outliers from the database fully confirmed the obtained results. Thus our meta-analysis showed that the DTW index in its current form is not a fully reliable predictor of soil areas that could be particularly sensitive to machinery-induced disturbance. It is therefore recommended to use the DTW index to create trafficability maps, always taking into account that the results of the algorithms should be validated in the field before starting harvesting operations.

Nutritional value, bioactive composition, physico-chemical and sensory properties of Ulva sp. and Fucus vesiculosus depending on post-harvest processing: a drying comparison study

Drying is an important post-harvest process to preserve seaweed as they are highly susceptible to spoilage due to their high moisture content. Drying can be performed in multiple ways by changing the temperature, pressure, air flow, and humidity. Therefore, the choice of drying method can affect the quality of the product in terms of sensory, chemical, and physicochemical properties. Seaweeds contain nutrients (protein, lipids, carbohydrates, vitamins, and minerals) and bioactive compounds. The compounds impact properties such as texture, taste, odor, and appearance. However, there is currently limited knowledge about how different drying methods affect the quality of seaweed products. In this paper we demonstrate, how different drying methods: i) convective drying (52 °C), ii) microwave-vacuum drying (-40 to 40 °C at 10 Pa), and iii) freeze-drying (-20 to 20 °C at 20 Pa) influence the food quality of Fucus vesiculosus and Ulva sp. by investigating physico-chemical properties such as water holding capacity, water absorption, and color, the changes in some of the chemical compounds such as macronutrients, fatty acids, amino acids, antioxidants, and pigments, as well as the taste, odor, appearance, and texture within sensory attributes. This study found that different drying methods have a species-dependent influence on the quality of seaweed, with Ulva sp. showing more similarities of using microwave-vacuum and freeze-drying methods, while the drying method for F. vesiculosus should be selected based on the desired food quality due to significant variations between the drying methods.

TA and CTAB treatment synergistically enhance activated sludge dewatering by lowering proteins and boosting Zeta potential

Waste activated sludge (WAS) is produced by urban sewage treatment plants, which contains pathogenic microorganisms, chemical elements, wiht high moisture content (>99%). To mitigate environmental pollution and reduce the volume of WAS, sludge dewatering are widely needed. The main objective of this study is to investigate the improvement in sludge dewaterability through the combined efficacy of tannic acid (TA) and cetyltrimethylammonium bromide (CTAB). Significant reductions in Capillary Suction Time (CST), Specific Resistance to Filtration (SRF), and moisture content of vacuum-filtered sludge cake (WC) were observed as experimental findings demonstrated the combined use of TA and CTAB. Specifically, CST decreased from 78.6 s to 15 s, SRF reduced from 1.12×1013 m/kg to 2.23×1012 m/kg, and WC decreased from 97.98% to 74.80%. The levels of polysaccharides and proteins present in various layers of the extracellular polymeric substances (EPS) within the sludge were reduced due to the interaction and formation of protein complexes with TA and CTAB. Additionally, these additives neutralized surface with a negative electrical potential of EPS, decreasing repulsion among sediment particles. This led to a decrease in the Zeta potential, while the contact angle and particle size of the sludge increased. Additionally, the hydrophobicity of the sludge particles was enhanced. As a result, intracellular moisture was released by disrupting the sludge cells. The findings presented here may assist in the development of sustainable and productive strategies for the management of sludge, ultimately promoting environmental protection and the well-being of urban communities.

Enzyme-induced Carbonate Precipitation (EICP) Combined with Lignin to Improve the Unconfined Compression Strength (USC) of Shanghai Clay

In order to improve the mechanical properties of high moisture content and low strength of clay particles in Shanghai, the effects of different lignin content on the unconfined compressive strength of EICP-lignin-cured clay were studied by using the method of lignin combined with EICP technology to strengthen the clay by lignin combined with EICP technology. The experimental results showed that EICP-lignin could enhance the unconfined compressive strength of Shanghai clay. With the increase of lignin content, the unconfined compressive strength of clay first increased and then decreased, and there was an optimal content value. The optimal lignin content is 8%.

Dehydration and Environmentally Friendly Thermal Processing of Excess Activated Sludge

Introduction. Currently, there is a problem with the accumulation of large amounts of production waste. One type of this waste is excess activated sludge, which is a waste product from biological wastewater treatment that has a high moisture content. When excess activated sludge is deposited in beds, problems can arise related to changes in the gas-air environment, the release of unpleasant odors, as well as the contamination of groundwater and soil. Prolonged presence of sediment in sludge beds in oxygen-free conditions leads to its decay and deterioration of moisture-yielding properties. For these reasons, the development of new methods for disposing of large volumes of waste generated during wastewater treatment is essential. The aim of this research is to develop a technique for preliminary neutralization and thermal treatment of excess activated sludge using energy waste. Materials and Methods. The work used excess activated sludge with a moisture content of 98.2% (waste of hazard class IV). Water treatment sludge (waste of hazard class V) was used as a reagent to increase moisture yield. For experimental studies on dehydration, a laboratory centrifuge Elmi CM-6M.01 was used. Tests were conducted under various conditions (500, 1 000, and 1 500 revolutions per second for 1, 2, and 3 minutes), and the value of centrifugation was determined as a criterion for moisture yield in the sludge. Fuel pellets were produced by rolling with technical lignosulfonate as a binding agent. Elemental analysis of the samples was conducted to study the possibility of thermal treatment using an EA 3 000 Euro Vector Analyzer. Results. A comprehensive technology has been developed to clean the resulting gas emissions from solid particles formed during the combustion of fuel pellets and remove them from the furnace in the form of fly ash along with the outgoing gases. This technology also removed sulfur oxides, nitrogen oxides, and polychlorinated dibenzodioxins and dibenzofurans, while beneficially utilizing flue gas heat by reducing its temperature from 900–1 200°C to 140°C. Discussion and Conclusion. The approach proposed in this article for the processing and disposal of large volumes of waste allows for the reduction of moisture content of excess activated sludge and the use of this waste as a secondary energy source. This method is environmentally friendly and addresses both technical and environmental challenges, such as the effective recycling of industrial waste and reducing the anthropogenic impact on soil, air, and groundwater. It also provides an opportunity to generate additional electrical and thermal energy through thermal utilization of waste. The results of this work indicate that it is possible to integrate the use of various types of industrial waste (sewage sludge, water treatment waste, and pulp and paper industry waste) as secondary energy sources. These findings have practical implications for enterprises in both the municipal and industrial sectors with wastewater treatment facilities.

Comparative study on physical properties of bio-based PA56 fibers and wearability of their fabrics

Abstract Bio-based polyamide 56 (PA56) has significant advantages in reducing oil dependence and reducing carbon emissions. This study compared the physical properties of bio-based PA56 and conventional polyamide 66 (PA66) fibers and their fabrics. The results showed that due to the odd arrangement structure of carbon atoms in PA56 fiber molecules, its crystallinity and orientation were lower than those of PA66. At the same time, PA56 had a higher degradation rate and coloring rate due to its smaller crystallinity and higher moisture content and gave PA56 fabrics better instantaneous cooling and moisture absorption and drying properties. In addition, the molecular structure characteristics of PA56 also lead to a lower stiffness and soft feel of the fabric, which is beneficial for improving the curling phenomenon of the fabric. Overall, bio-based PA56 fibers can meet the applications in the textile and clothing field and can largely replace PA66, which is worthy of further research and utilization.

Adaptation of breakthrough models in a continuous-flow fixed bed column: Describing and predicting 1.1.1.2-Tetrafluoroethane breakthrough curves under high moisture content

Gas mask and filter adsorber designs are mainly determined by the accurate breakthrough time calculated by fitting descriptive models to breakthrough curves in military chemistry. Currently, in most practical environments, the highly toxic fluoride gas/vapor breakthrough curves with roll-up and/or stepwise breakthrough structures in the C/C0<1.0 range usually occur, which is induced by the existence of pre-adsorbed water vapor. Common and easily modified descriptive breakthrough models have a significant shortcoming in that they are not able to simultaneously fit the above complex breakthrough curves and explain gas desorption, enhanced adsorption again, and stepwise adsorption in the competitive adsorption process. This study adapts three modified descriptive models by introducing a dimensionless breakthrough coefficient to fit roll-up and stepwise 1.1.1.2-Tetrafluoroethane (R134a) breakthrough curves under humid conditions. Results reveal that correlation coefficients between the model and R134a breakthrough data are higher than 0.98, demonstrating that the novel adaptation successfully accounted for R134a desorption, enhanced R134a adsorption again, and R134a stepwise adsorption without significantly increasing the complexity of implementing the models. Further, through relationship curves between fitting parameters and moisture contents, R134a breakthrough curves on activated carbons under a wider moisture content range were successfully predicted. It will greatly reduce the cost of toxic experimentation and improve experimental safety factors.

An Overview of the Thermochemical Valorization of Sewage Sludge: Principles and Current Challenges

With the increase in the world population and economic activity, the production of sewage sludge has grown, and its management has become an environmental problem. The most traditional method of managing sewage sludge is to dispose of it in landfills and on farmland. One way to valorize sewage sludge is to use thermochemical conversion processes to produce added-value products such as biochar, biofuels, and renewable gases. However, due to the high moisture content, thermochemical conversion using processes such as pyrolysis and traditional gasification involves multiple pre-treatment processes such as material drying. Hydrothermal thermochemical processes usually require high pressures, which pose many challenges to their application on a large scale. In this work, the advantages and disadvantages of the different existing thermochemical processes for the recovery of sewage sludge were analyzed, as well as the resulting industrial and environmental challenges. A SWOT analysis was carried out to assess the different thermochemical processes in terms of technical feasibility, economic viability, and broader market considerations.

Thermodynamic analysis of temperature boosting of hot primary air in an ultra‐supercritical lignite‐fired power plant: Scheme comparison and performance enhancement

AbstractLignite‐fired boilers usually encounter the insufficient drying capacity of the pulverizer due to the inherent drawback of high moisture content in fuel. In this study, four schemes of heat sources for temperature boosting of hot primary air are proposed for an ultra‐supercritical large‐scale single reheat lignite‐fired power plant according to heat sources such as inlet flue gas of air preheater (Scheme 1), the third stage extraction steam (Scheme 2), outlet steam of low‐temperature reheater (Scheme 3), and inlet flue gas of economizer (Scheme 4). The thermodynamic system models are built by using EBSILON Professional software. The thermodynamic performance of the four schemes is analyzed and compared from the perspectives of the first and second laws of thermodynamics. First law analysis indicates that the power generation standard coal consumption of Scheme 3 is reduced by 0.87, 0.42, and 0.04 g·kW−1·h−1 compared with Schemes 1, 2, and 4, respectively. Second law analysis indicates that the exergy loss of Schemes 2–4 is 3.7, 7.6, and 7.5 MW lower than that of Scheme 1. The present study may provide guidance for the energy efficiency improvement of lignite‐fired power plants.

Origin and Geochemical Characterization of Groundwater from Coal Seam: A Case Study of Balasu Coalfield, Ordos Basin.

The hydrochemical characteristics of groundwater are of great significance for studying the source, development, and utilization of groundwater. This study investigated the characteristics of anions and cations, total dissolved solids (TDS), hydrochemical types, and hydrogen and oxygen isotopes of surface water and groundwater in the Balasu coalfield. By conducting experiments using inductively coupled plasma emission electron spectrometry, ion chromatography, acid-base titration, and gravimetric analysis, the characteristics of ion concentration and TDS in different aquifers were analyzed to determine the possible source of groundwater in C2 (number 2 coal seam in Yan'an Formation). The Piper trilinear diagram was used to determine the hydrochemical types of aquifers, and the source of groundwater was determined based on the stable isotope characteristics of hydrogen and oxygen. The changes in ion, TDS, hydrogen, and oxygen isotopes of surface water and groundwater were analyzed, and the groundwater differences between the two sets of coal seams were compared. The research results indicate that the groundwater in C2 (number 2 coal seam in Yan'an Formation) is caused by the original sedimentary water and the infiltration of Zhiluo Formation and A1 (strata at the top of the Yan'an Formation to number 2 coal seam). However, C4 (number 3 coal seam in Yan'an Formation) is hindered by the well-developed mudstone in A3 (bottom of number 2 coal seam to the top of number 3 coal seam), which hinders the infiltration of groundwater. The study emphasizes that the overlying strata can have a significant impact on the coal seam when the moisture content is high and there is a lack of overlap, thereby promoting changes in the moisture content of the coal seam. This study provides some insights into the safety of coal mines, especially in mining areas with a high coal seam moisture content.

The Impact of Beaver Dams on the Dynamic of Groundwater Levels at Łąki Soleckie

Areas excluded from agricultural production are susceptible to the presence of beaver families. The most significant changes occur during the initial period, when agricultural utilization is abandoned and beavers establish their presence on the land. During this period, some parcels remain uncultivated, while agricultural activities persist in neighboring areas. This situation is accompanied by the destruction of beaver dams, especially during periods of abundant water resources, and notably during intensive fieldwork. The article presents field studies aimed at determining the extent to which constructed and operational beaver dams contribute to changes in groundwater levels in drained peatland areas. In order to protect and sustainably use peat soils, it is necessary to maintain their high moisture content by ensuring a high groundwater level elevation. This can be achieved through the use of existing damming structures in the area (levees, weirs). Beaver dams can also serve a similar function, blocking the outflow of water from peat lands by raising the water level and consequently retaining it naturally. The specific objective was to develop principles for verifying factors influencing the effects of beaver dam construction on groundwater levels in fields within their range of influence. The water table levels within the study area during rainless periods were influenced by water levels in ditches, dependent on beaver activity in the nearby river. Beaver activities, manifested through dam construction, were influenced by periodic water resources in the river, defined by the cumulative monthly precipitation. Factors affecting groundwater levels in rainless periods on the plots also included the distance from the river cross-section and the permeability of soils expressed by the filtration coefficient of the active layer. Beaver dams had the greatest impact on stabilizing the water table in the soil profile closest to the river.

Drying characteristics and kinetics of bottle gourd using stand-alone indirect solar dryer

Drying food is an effective method to preserve fruits and vegetables, increasing their shelf life and preventing germination. Bottle gourds, known for their high nutritional value, can rot quickly due to their high moisture content, causing biochemical and microbial changes. To improve shelf life, moisture can be removed to prevent microbial activity. Different drying methods are used to preserve gourd family vegetables for long periods and off-season. Indirect solar drying shields foods from UV rays, dust, insects, and other contamination by avoiding direct exposure. This study aimed to utilize an indirect solar dryer to research the potential for drying bottle gourds and conduct physicochemical analyses for the dried products to compare the drying techniques. In this experiment, different samples of bottle gourd slices were dried using an indirect solar dryer and compared with sun and shade drying. Under physicochemical properties, moisture content (MC), retention of color, thickness, and shrinkage of dried samples were analyzed and compared. The result showed that the time taken to reach 10% moisture was 13 h for samples dried with sun drying. While shade and indirect solar drying took 17 h. The Midilli-Kucuk model outperforms other approaches for drying bottle gourd, with the greatest R2 values (0.9967, 0.9950, 0.9936) and the lowest RMSE values (0.0182, 0.0220, 0.0277) for direct sun, shade, and indirect solar drying, respectively. The indirect sun dryer showed good color retention compared to the fresh bottle gourd samples with L* value of 44.08, b* value of 15.40 and a* value of 7.01. The volumetric shrinkage was 97.64% in the direct sun drying method after 15 h, which is higher compared to sun and shade dryers due to the effect of time and temperature. In addition, there was a significant difference (p-value &amp;lt;0.05) between the thickness of the three drying methods. The use of indirect solar drying methods can be highly recommended to get high-quality dried food with zero energy cost. For future studies it is recommended to enhance the function and design of the indirect solar dryer to speed up drying times and improve the quality of dried samples.

Sludge deep dewatering by liquefied dimethyl ether: selection of operating conditions based on response surface methodology

ABSTRACT Sludge is an inevitable by-product of the sewage treatment process and its high moisture content poses significant challenges for its treatment and disposal. This study focuses on the technology of sludge deep dewatering using liquefied dimethyl ether (DME) and explores the relationship between operating parameters (DME/sludge ratio, extraction time and stirring speed) and the water content of the sludge after deep dewatering. After deep dewatering, the sludge's lower heating value (LHV) was significantly increased. The dehydrated filtrate is highly biodegradable and could be treated together with sewage. Based on the response surface method of central composite design, a second-order regression model of the above three variables and sludge water content as the response was established. Finally, the operating conditions diagram was drawn by target water content (36.96 wt.%) which meets the requirement of self-sustained incineration and model equation. This study provides a valuable perspective on sludge drying and fuelisation.