Initial Moisture Research Articles

ИССЛЕДОВАНИЕ УСТАНОВКИ С ИНФРАКРАСНЫМ НАГРЕВОМ ЗЕРНА

Thermal post-harvest processing of grain currently intended to improve its quality is highly energy-intensive and expensive. The development of new means of mechanization with infrared heating of grain, capable of reducing specific energy costs for heat treatment processes, as well as ensuring resource conservation, is a pressing and important scientific and technical problem. To reduce the cost of drying, disinfection and micronization of grain, as well as improve the quality of its heat treatment, we have developed an experimental model of an installation with infrared heating. The study of the developed installation was carried out in grain drying mode. The technological process of drying wheat grain with an initial moisture content of 18...19% was chosen as the object of study. The total specific energy consumption for grain drying was taken as an optimization parameter. The rational values of the selected factors were determined as a result of a study of the developed installation with infrared heating of grain: grain drying time t1 = 1000C; the temperature created by the infrared heater inside the installation casing is tin = 650C. Next, a series of experiments was carried out on the developed installation in the above modes. In each experiment, measurements were taken of the heating temperature of the grain, the percentage of reduction in grain moisture content and the throughput of the installation were determined, and the total specific energy consumption was recorded. The heating temperature of the grain was in the range of 37 - 38.5 ºС, while the moisture content of the grain decreased by 2.56%. The developed installation provides the required quality of grain drying, maintaining a throughput of about 800 kg/h and a minimum total specific energy consumption, which amounted to 4342.3 kJ h/kg.

Drying of Highland Bamboo (Oldeania alpina) Culms Grown in Ethiopia as Quality Enhancement

Drying is an essential step in the manufacturing process of bamboo culms which enhances its quality. Even though in the case of Ethiopia, effective bamboo culm drying has not been practiced. This is due to limited information/technology regarding bamboo culm drying. Therefore, this study aimed to investigate the effective drying technologies and the effect of site and culm height on the drying characteristics of Oldeania alpina (O. alpina). For this study, matured 3-5 years old samples of O. alpina culms sectioned into three segments were collected from Hagere-Selam and Rebu-Gebeya, Ethiopia. The culms were stacked and dried using kiln and air-drying methods. The mean values of basic density in O. alpina collected from Hagere-Selam and Rebu-Gebeya sites were 0.65 and 0.63 gcm-3, respectively. The average initial moisture content (MC) of Hagere-Selam and Rebu-Gebeya culms were 91.78% and 80.32%, respectively. The Hagere-Selam culm kiln-dried within 6.5 days while air-dried within 75 days to attain the final MC for kiln (10.15%) and air-drying (14.13%). The Rebu-Gebeya culm kiln dried within 5.4 days while they required 61 days for air-drying to attain the final MC for the kiln (10.60%) and air-drying (13.01%). The MC and drying time needed for drying the culms were significantly affected by site, culm height, and drying method. Drying O. alpina culms using kiln and air-drying methods was successful without significant drying defects. Well-seasoned culms of Hagere-Selam and Rebu-Gebeya are recommended for wider utilization in Ethiopia including furniture, flooring, handcrafts, etc.

Heat consumption and modeling of corn seeds intermittent drying

AbstractBackgroundCorn seed is produced on a large scale, and as production is carried out seasonally, the storage is needed to supply uninterrupted demand. To carry out the storage, as the material from the harvest has a high initial moisture content, it is necessary to carry out the drying process. In order to reduce energy consumption, an alternative is intermittent drying. The purpose of this article is to fit the mathematical model of intermittent drying by distributed parameters, based on experimental data of temperature and moisture content of corn seeds submitted to intermittent drying, to determine the diffusivity value and to assess heat consumption.ResultsFor samples dried to the final moisture content of 16.0% on dry basis (d.b.), the condition of intermittent drying at a temperature of 40°C and 10 min of tempering period led to the lowest heat consumption, in comparison to conventional drying and to intermittent drying under higher temperatures. In addition, to obtain a final moisture content of 14.0% (d.b.), the conventional drying condition at 55°C resulted in the lowest heat consumption, compared to the other drying conditions. The distributed parameter model can predict the experimental data with a global deviation lower than 10.0%.ConclusionAnalyzing the moisture distribution profiles for the corn seeds, it was verified that there was a difference in the moisture content along the position inside the material, being necessary to evaluate the influence of moisture distribution along the position inside the material in kinetic drying models.

Influence of initial moisture content on creep and shrinkage of concrete at constant and cyclic ambient humidity

Creep and shrinkage are strongly influenced by the moisture content of concrete and by the ambient humidity. The effect of the latter is currently considered in models and design codes such as the fib Model Code 2010 by time-average considerations, thus totally neglecting cyclic changes in ambient humidity normally observed in outdoor structures. However, the influence of the cyclic ambient humidity on the long-term deformations of concrete compared to the constant mean humidity has barely been investigated. Therefore, the developments of creep and shrinkage of a normal-strength concrete C30/37 with three initial (before testing) moisture contents at constant humidity as well as cyclic humidity were investigated. Results demonstrate that the drying shrinkage and drying creep, but also the basic creep, are higher with higher initial moisture contents at constant ambient humidity conditions. Additionally, creep strains sharply increased up to plus 60% due to cyclic humidity compared to those due to corresponding average constant humidity. The influence of cyclic ambient humidity is more pronounced for concretes with lower initial moisture contents. Those strong deviations in the creep behaviour (compared to existing design models) may cause severe safety risks in prestressed concrete constructions. Therefore, existing creep models should be modified considering the influence of cyclic changes in humidity and the combined influence of the initial moisture content.

Using cellular automata to simulate external heat and mass transfer in the wood drying process

This work involves modeling the external heat and mass transfer in the wood drying chamber. One of the remarkable features of this research is to use cellular automata with variable cell sizes closely related to the geometric parameters of the considered wood materials. This approach allows for modeling and analyzing the changes in the characteristics of wood materials during the hydrothermal treatment process, taking into account their unique geometry. Such modeling provides valuable information about how different shapes and sizes of wood react to various drying conditions. This research has significant implications for industries dependent on wood drying, such as construction and furniture production, as it offers an individual approach to upgrading the drying processes of wood materials with different geometries. The modeling in this work is carried out using wood materials, primarily pine, with a standardized thickness of 25 mm and an initial moisture content of 30 %. The modeling is conducted under conditions of moderate drying, accurately mirroring real-world scenarios. Using pine as the researched material aimed to represent a widely used wood species in the industry, thereby increasing the relevance of the results. The work also explores the influence of various parameters of the wood drying agent. To achieve this, three key factors are systematically varied: temperature, relative humidity, and drying agent velocity. Temperature fluctuations are carried out within a range of ±10 °C. Similarly, relative humidity is adjusted within ±10 % of standard technological parameters. Finally, the drying agent velocity was increased to a maximum of 6 m/s. Thus, the impact of these changes on the moisture content in wood materials is investigated. The results obtained can be applied in an industrial setting. The knowledge gained from the experiments can play a crucial role in improving the wood drying process. In summary, the work investigates the hydrothermal treatment of wood materials, shedding light on the critical role of wood drying agent parameters in controlling moisture content in wood materials. The potential advantages in terms of product quality and overall production efficiency cannot be overstated, and it is expected that this work will be a valuable resource for industries dependent on wood processing.

A novel infrared drying technique for processing of apple slices: Drying characteristics and quality attributes

Most conventional drying methods often result in significant degradation of food items' flavor, color, and bioactive compounds due to the drying process. One of the effective drying methods for improving food quality and reducing the drying process's duration is applying heat through infrared radiation. Infrared-dried apple slice quality was evaluated experimentally and statistically in terms of the drying period, rehydration ratio, colour, and shrinkage as a function of infrared intensity levels, slice thicknesses, and air velocity. Apple slices were dried at infrared intensities of 0.130, 0.225, and 0.341 W/cm2, air velocities of 1.0, 0.5, and 1.5 m/s, and slice thicknesses of 6, 4, and 2 mm. Throughout the procedure, the dried slices were reduced from an initial moisture content of 87.5 %–11 % (w.b.). According to the findings, the drying time needed to decrease the moisture level of sliced apples to roughly 0.12 g water/g dry matter ranged from 200 to 280 min, 170–240 min, and 130–190 min at infrared radiation intensities of 0.130, 0.225, and 0.341 W/cm2, respectively. Water activity values for dried apple slices ranged from 0.371 to 0.450. The rehydration ratio increased with increasing air velocity and reduced with increased infrared radiation intensity. In contrast, the shrinkage ratio increased with increased infrared radiation intensity and decreased with increased air velocity. Slices of fresh and dry apples had a more significant overall colour difference as radiation intensity and air velocity increased.

Biological denitrification inhibition (BDI) on nine contrasting soils: An unexpected link with the initial soil denitrifying community

Denitrification is considered the major pathway leading to soil gaseous (N) losses, affecting N availability for plants and consequently plant productivity. Biological denitrification inhibition (BDI) in Fallopia spp., a plant species complex with a high level of growth and competitiveness for mineral N, acts through procyanidin production. However, the soil factors governing BDI development are still unknown. Through a mesocosm experiment using two treatments – soil planted with Fallopia japonica and unplanted–, nine biologically and physically contrasting soils were studied with the aim to ascertain how each can affect BDI development. Microbial enzyme activities (respiration - SIR, denitrification - DEA), denitrifying functional gene abundance (nirK, nirS), total bacterial community abundance (rRNA 16S) and soil physicochemical parameters (N mineral forms, soil texture, moisture, pH) were measured before and after plant growth, and the DEA:SIR ratio was used as a BDI proxy. The DEA:SIR ratio decreased for six soils. BDI development is related to a small number of soil factors, mainly initial soil moisture and ammonium concentration, and unexpectedly, with the initial abundance of nirK(in), nirS(in) and rRNA 16S(in). The intensity of this decrease is positively correlated to the level of DEA in unplanted soil: the higher the DEA in unplanted soil, the more intense the BDI under F. japonica. The procyanidin concentration of the F. japonica belowground system was positively correlated to BDI intensity. These results suggest that a procyanidin assay from the plant belowground system could be a new proxy for measuring BDI intensity. Interestingly, this research shows that BDI is not systematic, and that few (a)biotic soil parameters influence its development. More importantly, this research is the first to highlight that biotic factors are relevant in explaining BDI. This paper also presents new perspectives on plant-microorganism interactions in terms of plant awareness of the soil microbial community.

CO2 monitoring associated with the quality of soybean grains stored in different moisture contentes

The objective of this study was to quantify the levels of CO2 produced by soybeans stored at room temperature in a prototype silo, with initial moisture contents of 12, 14, and 16% (w.b.), as well as to evaluate the quality of the product over storage. Analyses of the moisture content, ash, proteins, lipids, color, germination, and electrical conductivity were performed. In the atmosphere in the silos, the amount of CO2, relative humidity, and temperature were monitored every hour using a CO2 meter data logger. Grain quality evaluations took place at four storage times (0, 30, 60, and 90 days). Analyses were performed in triplicate, and data were analyzed using analysis of variance and regression, adopting the 5% level of significance. The moisture contents, protein, lipids, germination, and color were reduced over time, resulting in a loss of grain quality. Soybeans initially stored with 16% (w.b.) of initial moisture content showed greater losses associated with the rise in the levels of CO2. The rise in CO2 emission in the internal atmosphere of the silo signals the beginning of grain deterioration and can be used as a decision-making tool, aiming at preventing and reducing losses in product quality over storage.

Performance evaluation of innovative sensible energy storage material integration as an obstacle in solar collectors for drying applications

This research paper presents an innovative approach to enhance the performance of solar collectors in drying processes by integrating a sensible energy storage material within the airflow passage as an obstacle. The study involves a real-time comparative analysis of different collector configurations, under identical meteorological conditions, including flat collector, finned collector and rock integrated collector. The experimental results demonstrate that at high flow rate the collector equipped with fins achieves higher outlet temperatures, with a maximum of 59.8 °C, compared to 58.2 °C for the collector without fins. Additionally, for low and intermediate flow rates, the collector utilizing rocks as the energy storage material exhibits a maximum outlet temperature of 70.2 °C, while the collector with fins reaches 76.8 °C. Notably, the collector with rocks demonstrates a temperature gain of 13.6 °C during the night period. The drying efficiency of both solar dryers is evaluated, and they achieve a final moisture content of 6 % from an initial moisture content of 88 % (kg water/kg wet basis) in 1452 and 1722 min in solar dryer with fins and rocks, respectively. The drying rate is observed to be higher in the solar dryer with fins compared to the one with rocks. Midilli-Kucuk model provided the best agreements between experimental and predicted moisture ratios. Furthermore, the average effective moisture diffusivity is found to be higher in the solar dryer with fins (6.39485E-10 m2/s) compared to the one with rocks (1.33512E-10 m2/s).

Prediction of wood drying process based on artificial neural network

Taking the conventional drying process of Pinus sylvestris square wood with pith as the research material, based on the Back Propagation (BP) neural network algorithm, a model was constructed using the real-time online-measurement data. Softening treatment time and temperature, variable treatment time and temperature, initial moisture content of wood, and position of wood core and sapwood were used as model inputs. Wood drying rate and longitudinal cracking degree were used as outputs to indicate wood drying quality. The results showed that with a suitable model structure of 6-9-2 (input layer-hidden layer-output layer), the coefficient of determination R2 and mean square error of the test samples were 0.96, 0.99, and 0.00605, respectively, indicating that the neural network model has good generalization ability. Compared with the experimental value, the predicted value basically conforms to the change law and size of the experimental value, and the error distribution is approximately 2%. This shows that the BP neural network model can simulate the drying rate and longitudinal cracking degree in the drying process and realize the prediction of the drying process.

Moisture content effects on self-heating in stored biomass: An experimental study

Biomass is essential for modern bioenergy applications, but long-term storage of large volumes of it can pose challenges to plant safety due to the intrinsic self-heating characteristics of biomass piles. In recent years, serious fire accidents have occurred because of self-heating. However, little research has been conducted on this concern. The effects of different initial moisture contents (range of 20–95 %) on the self-heating characteristics of rice and wheat straw, which are two different agricultural biomass residues, are investigated in this study. Biomass samples with different initial moisture contents are stored in a well-insulated container, and the temperature and oxygen levels within the stored biomass samples are monitored. Based on the tests, the heat production rate, oxygen consumption rate and microorganism growth rate are derived, and the impacts of the initial moisture contents on the self-heating characteristics of the stored biomass samples are analysed. The highest temperatures in the stored rice straw and wheat straw are attained under initial moisture contents of 50 % and 20 %, respectively, while the largest heat production rates for both straw types are attained under an initial moisture content of 95 %. An increase in the initial moisture content greatly enhances the overall biological reactivity and oxygen consumption rate. The heat production and oxygen consumption levels exhibit a clear positive correlation. Under identical storage conditions, wheat straw is more susceptible to self-heating than rice straw, as shown by its higher heat generation, faster oxygen consumption, and shorter temperature peaking time. This study contributes to a quantitative understanding of the underlying processes and provides valuable experimental data for model development to guide safe biomass storage systems.

Exploring an intelligent adaptation method of hydrological model parameters for flood simulations based on the light gradient-boosting machine

Traditional hydrological modeling methods use a set of parameters to simulate flood processes with complex causes and variable intensity, which can easily lead to parameter instability. To address the problem of parameter instability, this study proposes an approach integrating the hydrological model with Intelligent Adaptation Parameters (IAP), whose intelligent adaptation relationship is established by the light gradient-boosting machine (LightGBM) based on individual calibration parameters by each flood event and flood characteristics including flood-caused rainstorm information and initial soil moisture. A widely used hydrological model, Xin 'anjiang (XAJ) model, is chosen to be integrated with IAP (XAJ-IAP) in this study, which has a relatively complex structure and a total of 15 model parameters. The obtained findings demonstrate that: (1) recalibrating the sensitive runoff concentration and separation parameters with a single flood leads to a notable enhancement in simulation accuracy, while simultaneously considering the model's physical significance; (2) the XAJ overestimates large floods and underestimates small floods. Compared with the XAJ, the XAJ-IAP has a better rain-flood response relationship and simulation accuracy for floods of different magnitudes, solving the problem of parameter instability that exists in XAJ; and (3) evaluated in terms of information gain, sensitive parameters contribute the most to the establishment of the intelligent adaptation relationship in the LightGBM compared to flood-caused rainstorm information and initial soil moisture, indicating that sensitive parameters are the most important input features of the LightGBM. It can be concluded that the intelligent adaptation system can not only solve the problem of parameter instability that exists when traditional hydrological models simulate complex and changeable floods, but also further reveal the relationship between the model and floods.

Influence of hot-air drying on the starch structure and physicochemical properties of two corn cultivars cultivated in East China

In this study, Denghai-685 and Xianyu-335, two major corn cultivars cultivated in East China, underwent hot air drying with different initial moisture contents (20, 25, and 30%) and drying temperatures (60, 90, and 120 °C). The study analyzed the dried corn kernels' starch structure and physicochemical characteristics. Hot-air drying altered the starch shape, transforming it from spherical to polyhedra. This process also reduces the amount of amylose in corn compared to naturally dried samples. Interestingly, higher drying temperatures (90 and 120 °C) increased gelatinization temperature but decreased other gelatinization parameters for both cultivars. The transparency of starch pastes from the two cultivars was improved, but the retrogradation was weakened. The onset, peak, and conclusion temperatures of starches increased as the drying temperature rose, while the gelatinization enthalpy decreased. Hot-air drying increased the relative crystallinity of starches of the two cultivars, peaking at 60 °C. The changes in values of R1047cm−1/1022cm−1 and R995cm−1/1022cm−1 deduced from infrared spectroscopy suggested that hot-air drying promoted a more ordered crystalline structure of starches from the two cultivars. These findings suggested that the physicochemical and structural characteristics of starches from the two cultivars were significantly influenced by the interaction of initial moisture content and heating temperatures.

Determining the Stabilised Subfoudation Soil Deformation Modulus According to the Plate Load Tests and Geotechnical Monitoring Data

Introduction. The subsiding soils, which are widely spread in the south of Russia, create a number of problems and hazards due to the high probability of subfoundations subsidence in case of exceeding the values of initial soil moisture and initial pressure for subsidence. This is an important phenomenon to be considered at all life cycle stages of a building or structure, especially at the stage of design, when the scientifically justified design and technological solutions must be developed to ensure the reliable operation of facilities in the complicated engineering and geological conditions being studied hereby. The present article analyses the acting federal and regional regulatory and technical documentation in the field of buildings and structures design on the subsiding soils. Based on the numerical experiment, the incorrectness of the results sometimes received upon following the normative methodology is shown. A new calculating methodology based on determining the stabilised subfoudation soil deformation modulus according to the plate load tests and geotechnical monitoring data is proposed.Materials and Methods. The research comprised:– analysis of the existing approaches and methodologies for the subfoundations and foundations design on the subsiding soils;– numerical experiments, including calculations according to the normative methodology, which implied variation of the original data of both the initial properties of soils and technological parameters of stabilisation, as well as statistical processing of the results;– analysis of the carried out earlier by the authors geotechnical monitoring results of the buildings built on the stabilized soils and experimental study of the deformation properties using a patented device;– determining the main factors having influence on the design solutions for the subfoudation soils and building foundations strengthening under a complicated set of operational loads and establishing a new dependence of the stabilised soil deformation modulus on the initial soil deformation modulus and percentage of soil reinforcement.Research results. It has been established that the existing methodologies for calculating the stabilised subfoudation soils are not enough precise for determining the forecastable subsidence of buildings and structures, and the obtained design values do not always correspond to the factual deformations of subfoundations and foundations. The dependence of the stabilised subfoudation soil deformation modulus on the initial soil deformation modulus and percentage of soil reinforcement with the cement-sand mortar has been traced. A new calculating methodology has been developed based on determining the stabilised subgrade soil deformation modulus according to the data of the plate load tests using a patented device and geotechnical monitoring.Discussion and conclusion. It has been established that the deformation modulus of the soil mass stabilised by the cementation method depends non-linearly on percentage of soil reinforcement with the cement-sand mortar and the initial soil deformation modulus, and this dependence is described by a second-order surface equation of a general form. It is recommended to apply the discovered dependencies for designing the technological parameters of the subsiding soils stabilisation in the Rostov region conditions.

Formulation Containing Phytosomes of Crocin-Rich Extract from Nyctanthes arbor-tristis and Petroselinic Acid from Coriandrum sativum seeds Exhibits Sunscreen and Moisturizing Effects

Background: Orange coloured tubular calyx of Nyctanthes arbor-tristis can be utilized as a substitute for saffron due to the presence of crocin, an apocarotenoid, which can act as a sun-screen agent. Petroselinic acid is reported to have a moisturizing effect on the skin. Objective: To utilize the tubular calyx of Nyctanthes arbor- tristis as an economical source of crocin and Coriandrum sativum seed oil as a source of petroselinic acid for the development of a stable phytosomal gel formulation and to evaluate its sunscreen and moisturizing activities. Methodology: Phytosomes of standardized crocin-rich extract and petroselinic acid were prepared separately by lipid film hydration technique. The phytosomes were then incorporated into a gel base prepared from dehydroxanthan gum, and it was evaluated for in-vitro sunscreen activity by using Mansur’s equation. Moisturizing effect of the phytosomal gel was evaluated on 10 healthy female volunteers with their informed consent, and the water content of the stratum corneum was measured by using a Digital Moisture detector pen before and 5 hours later the application of the gel. Results: Mean initial moisture content of the skin was found to be 30.08 %, which was signifi-cantly (P < 0.05) raised to 45.59% at the end of 5 hours. Sun Protection Factor was found to be 15.09 and with a Boot Star rating of 2. Conclusion: Entrapping the phytoconstituents in vesicles increased stability, and the formulation was found to have moderate protection and a good moisturizing effect on the skin.

Machine learning-based prediction of internal moisture variation in kiln-dried timber

ABSTRACT Monitoring the moisture content uniformity in kiln-dried wood and preventing large gradients is vital as nonuniformity renders dried timbers susceptible to warpage and degrade. This research uses a gradient-boosting machine learning model to model kiln drying by providing a predictive approach to estimate moisture levels and gradients. A population of 378 western hemlock square timbers was assigned into nine drying batches, each undergoing a different drying schedule. Inputs were four timber attributes, i.e, initial and final moisture, initial weight, and basic density, and three drying parameters, i.e. drying schedule, end-schedule conditioning, and dried timber post-storage. The results revealed that drying schedules and post-storage significantly impacted moisture gradients, while the effect of conditioning was insignificant. All the input parameters were crucial in developing the predictive machine-learning model, where wood attributes had relatively higher importance than drying parameters. Also, outputs highly depend on final moisture after drying. The best training and testing performances were achieved when predicting the shell moisture, followed by the core moisture and moisture gradient. Further research is required to enhance the predictive performance of the moisture gradient predictive model. Future studies could also develop classification models for the moisture gradient beneficial to sawmills.

Physical modelling of climate-soil-infrastructure interactions of paved roadways constructed in expansive soil

Roadways founded on expansive soils are notorious for incurring damage in the months and years after construction. Soil swelling and shrinking manifest at the road surface as differential displacements of the pavement and eventually lead to linear cracks developing parallel with the direction of traffic flow. This climate-soil-infrastructure interaction occurs over daily, seasonal, and annual cycles that cause variations in moisture, temperature, relative humidity, and precipitation. Design recommendations often call for expansive soil to be compacted 1–2% wet of optimum to limit pavement damage regardless of the local climatic conditions or soil swell potential. Despite the prevalence of expansive soils found worldwide and the significant damage they cause to overlying infrastructure, very few studies appear in the literature that include field monitoring. To overcome this lack of physical data and examine the traditional design specification centrifuge modelling was undertaken to reproduce a stress-appropriate environment and control the moisture boundary conditions. These centrifuge experiments examine the effect of as-placed moisture content on the response of a two-lane paved road profile subjected to wetting–drying cycles. The centrifuge model results provide high temporal and spatial resolution displacement measurements using Digital Image Correlation. Cumulative subsurface strains are reflected at the road surface and cause detectable differential displacements of the model paved road. The relatively minor variation of initial moisture content in the three tests examined (varied from 29 to 34%) was found to have a significant impact on the hydraulic-mechanical response expressed in the isolated ground located beyond the influence of the road as well as the pavement-ground interface. The experimental results provide new insight into climate-soil-infrastructure interaction under a paved road, which would otherwise be unobservable using traditional discrete measurement techniques in the field. Interpretation of the high-density displacement measurements allowed for calculation of unique curvature / bending envelopes for the pavement under the different as-placed moisture conditions. The wet of optimum model displayed 5-times greater curvature / bending compared to the optimum and dry of optimum tests. Compacting wet of optimum may not be uniformly beneficial to limit pavement damage and construction specifications should consider local climate and swelling potential.

Prediction of Higher Heating Values in Bio-Oil from Solvothermal Biomass Conversion and Bio-Oil Upgrading Given Discontinuous Experimental Conditions.

Both the conversion of lignocellulosic biomass to bio-oil (BO) and the upgrading of BO have been the targets of many studies. Due to the large diversity and discontinuity seen in terms of reaction conditions, catalysts, solvents, and feedstock properties that have been used, a comparison across different publications is difficult. In this study, machine learning modeling is used for the prediction of final higher heating value (HHV) and ΔHHV for the conversion of lignocellulosic feedstocks to BO, and BO upgrading. The models achieved coefficient of determination (R2) scores ranging from 0.77 to 0.86, and the SHapley Additive exPlanations (SHAP) values were used to obtain model explainability, revealing that only a few experimental parameters are largely responsible for the outcome of the experiments. In particular, process temperature and reaction time were overwhelmingly responsible for the majority of the predictions, for both final HHV and ΔHHV. Elemental composition of the starting feedstock or BO dictated the upper possible HHV value obtained after the experiment, which is in line with what is known from previous methodologies for calculating HHV for fuels. Solvent used, initial moisture concentration in BO, and catalyst active phase showed low predicting power, within the context of the data set used. The results of this study highlight experimental conditions and variables that could be candidates for the creation of minimum reporting guidelines for future studies in such a way that machine learning can be fully harnessed.

Radio frequency drying and puffing of composite purple sweet potato chips

Radio frequency (RF) heating is a novel technology applied to drying and puffing. In the previous study, the optimal conditions for RF drying and puffing of composite purple sweet potato chips were 60% initial moisture content, 1 mm sample thickness, and 110 mm electrode gap. The effects of RF treatment temperature (50–110 °C) on the quality, physicochemical properties, and starch structure of composite purple sweet potato chips were further studied in this research. With the increase in RF treatment temperature, the protein, starch, and anthocyanin content in the samples were significantly reduced. However, the reducing sugar content, gelatinization degree, water absorption index (WAI), and water soluble index (WSI) were greatly improved. No new functional groups were produced after RF treatment. The starch changed from A-type to B-type crystal structure at temperature of 65 °C, which may result in the formation of a new double helix structure. Moreover, a larger irregular structure was observed at low temperatures of 50–65 °C, while this structure disintegrated into debris at high temperatures of 80–110 °C. This study provided a theoretical foundation for applying RF drying and puffing technology to starchy foods.

A Novel Analytical Solution for Ponded Infiltration With Consideration of a Developing Saturated Zone

AbstractPonding at the soil surface exerts profound impacts on infiltration. However, the effects of ponding depth on infiltration, especially the development of a saturated zone below the soil surface, have yet to be considered in present infiltration models. A new general Green‐Ampt model solution (GAMS) was derived for a one‐dimensional vertical infiltration problem under a uniform initial moisture distribution with ponding on its surface. An expression was included in the new solution for simulating the saturated layer developed below the soil surface as long as the pressure head at the surface is sufficiently high to saturate the soil. The GAMS simulates the infiltration processes closer to the numerical solution by HYDRUS‐1D than the traditional and the recently improved Green‐Ampt model. Moreover, an inversion method to improve the estimates of soil hydraulic parameters from one‐dimensional vertical infiltration experiments that is based on the GAMS was suggested. The effect of ponding depth (hp), initial soil moisture content, soil texture, and hydraulic soil properties (saturated hydraulic conductivity Ks, water‐entry suction hd and shape coefficient n of soil water retention curve) in the saturated zone was also evaluated. The results indicate that the saturated zone length increased at a comparable rate with the unsaturated wetted zone length during infiltration. Generally, a larger saturated zone was found for soils with higher initial soil moisture contents, coarser texture, higher Ks values, greater n, and lower −hd. Our findings reveal that including the saturated zone in the infiltration model yields a better estimate of the soil hydraulic parameters. The proposed GAMS model can improve irrigation design and rainfall‐runoff simulations.