Bed Dryer Research Articles

The characteristics of swampland rice farming in South Sumatra: local wisdom for climate change mitigation

Swampland has been used for agriculture for hundreds of years, yet most still use traditional ways. In general, rice farming in swampland is cultivated once a year before the dry season depending on land classification. This paper presents the swampland rice farming system’s role as local wisdom that needs to be maintained for environment preservation and climate change mitigation. Data was collected through interviews with farmers and extension workers and reviews of relevant experimental studies and articles. The success of rice farming in swampland is primarily determined by nature such as sudden flood and drought. Swampland is divided into three typologies, namely shallow swampland, mid swampland, and deep swampland. The nursery system and rice variety selection are key for successful rice farming in swampland. There are dry and floating nursery systems in South Sumatra. The dry nursery is carried out in dry land and field beds, usually done for shallow swampland; floating nursery is carried out in higher water level swampland using rafts made from waterweeds. Some of superior adaptive varieties in swampland are Inpara-1, Inpara-2, Inpara-4, Batutegi, Limboto, Inpari-1, Inpari-4, Inpari-6, Inpari-9 and Mekongga which may increase production in swampland.

Factors affecting evaporation of water from cattle bedding materials

In livestock farming, maintaining dry bedding is considered to be important for maximising animal performance and welfare. A better understanding of the mechanisms that regulate drying has the potential to improve bedding management and reduce production costs. A custom laboratory-scale method was developed to explore the effects of environmental conditions and bedding characteristics on drying rate (DR). Samples (n = 256) of different types of bedding materials were exposed to controlled environmental conditions by using a climate chamber equipped with a custom cabinet capable of simulating different levels of air velocity and bedding temperature. The effects of the type of material, bedding moisture content, bedding temperature, air temperature, air relative humidity (RH) and air velocity were evaluated in a full factorial experimental design. Under the experimental conditions tested, DR ranged from 0.28 to 6.04 kg m −2 d −1 , with an average of 2.03 kg m −2 d −1 . All variables significantly affected DR, but large variation in the magnitude of effects was found. Bedding moisture content, air velocity and air RH had considerably larger effects than the other variables, together accounting for more than 70% of the variance in DR. The DR from bedding samples increased with bedding moisture content and air velocity but decreased with increasing air RH. The results of the current study may have important implications in the design and management of bedded pack barns. To increase the DR and keep bedding dry, producers should focus primarily on providing adequate barn ventilation (both in terms of air velocity and air exchange), whereas maintaining a high pack temperature may yield poorer-than-expected results. • Water evaporation from livestock bedding materials has been measured experimentally. • Drying rate depends on environmental conditions and bedding characteristics. • Bedding moisture content, air velocity and air RH are the most important factors. • Producers with bedded pack barns should focus on providing adequate ventilation.

Control of septage sanitization by limes and lactic acid fermentation

Considering low-cost and effective fecal sludge (FS) treatment alternatives is essential to avoid risk to human health and to ensure safe disposal in landfills and soils. This research assesses optimal pH adjustment of two techniques for sanitizing de-watered FS from a septic sewage-treatment plant. The preliminary analysis evaluated the efficiency of lactic acid fermentation (LAF) by two lactic acid strains: Lactobacillus casei and Lactobacillus acidophilus. The homofermentative strain was chosen to evaluate three supplementary sugars: smashed carrot, sugarcane-derived molasses, and anhydrous dextrose. Lime treatment was examined using two materials, CaO, 105% calcium carbonate equivalent (CCE), and Ca(OH)2, 75% CCE. Four samples were retrieved from a passive thermal drying bed, two characterized by its available nutrient content; all samples were analyzed for the pathogenic profile, and total coliforms (TC) were selected as indicators. For LAF, an inoculating rate of Lactobacillus casei 10 g/100 g sludge was found effective in decreasing the pH below 4.0 after 30 days of fermentation, using 22% w/w dextrose/septage and 20% w/w molasses/septage, where molasses contains 20.7% of soluble sugars. In the case of lime treatment, the pH was fitted by a power-law relationship to the rate of lime applied in a septage with an initial pH lower than 7.0. A Langmuir type equation fitted better the liming of two septages with initial pHs above 7.0. The rate of lime CaO 10% w/w was observed to increase the pH above critical value, 12, after 1 h and 24 h. Analysis confirmed the total elimination of TC in samples with pH < 4.0 and pH > 12, contrasting the respective controls. Rates of CaO considering the initial pH of the FS are recommended in order to reach pH 12. Septage sanitization can be completed using either CaO or lactic acid fermentation with molasses; selecting the ideal method will rely on cost-benefit analysis. Sanitization can be considered as well to improve safety soil nutrient recycling practices.

A three dimensional dam break flow: Small time behavior

Small time behavior of gravity driven free surface flows resulting from the collapse of a cavity is studied. Initially there is a rigid vertical cylinder of circular cross section starting from the free surface of a liquid and ending at the rigid bottom. The cylinder disappears suddenly and gravity driven flow of the fluid starts. The flow in early stage is described by the potential theory. Attention is paid to the singular behavior of the velocity field at the intersection line between the bottom and the free surface of the cavity. The leading order linear problem is solved by the Fourier series method. The flow velocity is log-singular at the intersection line. In the limiting case where the radius and the center of the cavity approach infinity, the problem is reduced to the classical two dimensional dam break problem where the fluid is initially on one side of a vertical wall (dry bed case). The flow resulting from cavity collapse is a three dimensional dam break flow. It is concluded that the three dimensional effects are important when the radius of the cavity is small compared with its depth and that the local flow near the intersection line of the cavity is governed only by the hydrostatic pressure.

A fully Lagrangian DEM-MPS mesh-free model for ice-wave dynamics

This paper develops and evaluates a novel three-dimensional fully-Lagrangian (particle-based) numerical model, based on the hybrid discrete element method (DEM) and moving particle semi-implicit (MPS) mesh-free techniques, for modeling the highly-dynamic ice-wave interactions. Both MPS and DEM belong to mesh-free Lagrangian (particle) techniques. The model considers ice-wave dynamics as a multiphase continuum-discrete system. While the MPS solves the continuum equations of free-surface flow in a Lagrangian particle-based domain, the DEM uses a multi-sphere Hertzian contact dynamic model to simulate the ice floes motion and interaction. The hybrid model predicts the motion and collision of ice floes as well as their interaction with water, boundaries, and any obstacle in their way. Considering the mesh-free Lagrangian nature of both DEM and MPS, the developed model has an inherent ability to predict the free-drift (absence of internal stress) movements of the ice floes, e.g., sliding, rolling, colliding, and piling-up, in violent free-surface flow. A small-scale and challenging experiment based on dam-break flow over dry and wet beds with floating block floes, which mimics the characteristics of an idealized jam release, has been conducted to provide useful and comprehensive quality data for the validation of the proposed model, as well as other numerical models. Experimental and numerical results of the free-surface profile and the position of the blocks are compared. The results show the ability of the model to numerically reproduce and predict the complex three-dimensional dynamic behavior of wave-ice floes interaction. Overall, this study is a first effort toward developing an ice-wave dynamic within a fully Lagrangian framework (i.e. both flow hydrodynamics and ice dynamics in the Lagrangian particle-based system), and its results can be extended to bring an in-depth understanding of the physics of the real-scale ice-wave or river ice dynamic problems in the future.

Measurements of bed shear stresses near the tip of dam-break waves on a rough bed

Shear plates have previously been used to measure bed shear stresses under swash and dam-break waves. The present study has been focused on the large bed shear stresses near the tip and even at distances less than one plate length from the tip. In order to resolve this rapid stress variation, the shear plate was calibrated with respect to its step response as well as statically. Step response calibration enables the effects of the time lag and the natural frequency of the shear plate system to be removed. Thus, the initial variation of the bed shear stress during and just after the rise of the water level is resolved and opens the opportunity to investigate the boundary layer development close to the tip where other measurements have not previously succeeded. The bed shear stress $$\tau_{{{\text{bed}}}} \left( t \right)$$ initially increases almost linearly with time to a maximum, which occurs about 0.2 s after the passage of the contact point, while it takes about 2.0 s for the water surface level h(t) to rise to a quasi-steady level under the present experimental conditions. Thus, with h(t) and $$\tau_{{{\text{bed}}}} \left( t \right)$$ varying with different timescales, the simple assumption of $$\tau_{{{\text{bed}}}} = \tau_{{{\text{bed}}}} \left( {\frac{{{\text{roughness}}}}{{{\text{depth}}}}} \right)$$ is not supported. For a given dam-break, the peak bed shear stress depends on the tailwater level. In our tests with initial dam depth 400 mm and bed roughness 84 mm, $$\tau_{{{\text{bed}}}}$$ peaks at 210 Pa ± 20 Pa on dry beds decreases to peak values of the order 40 Pa with 98 mm tailwater depths. Quasi-steady $$\tau_{{{\text{bed}}}}$$ -values reached while the water surface is still quasi-steady, which are of the order 5–10 Pa. For dry beds, $$\tau_{{{\text{bed}}}}$$ shows a single peak followed by a smooth monotonical decay, while tailwater depths above 40 mm may lead to two almost equal, successive $$\tau_{{{\text{bed}}}}$$ -peaks and an oscillating decay.

Numerical Study of the Dynamics and Structure of a Partial Dam-Break Flow Using the VOF Method

This paper aims to evaluate the effects of the opening width of a dam site on the evolution of partial dam-break waves over a fixed dry bed. The volume of fluid (VOF) method was used to scrutinize the propagation of the dam-break free surface. The model was validated using experimental data provided in the literature. At the same time, a sensitivity analysis was conducted on the size of the mesh cells and the turbulence model. However, the large eddy simulation (LES) method showed the highest accuracy among all the models. The results affirmed the crucial role of the opening width of the dam site in the flow characteristics. In this direction, diminishing the opening width results in a reduction of the wave-front travel distance, free surface gradient within the reservoir, outflow discharge values, damping the outflow hydrographs and decreasing the Froude number values at the dam site. Conversely, this leads to an increase in the air bubbles entrained within the wave and results in energy dissipation across the downstream channel.

A locally implicit time-reversible sonic point processing algorithm for one-dimensional shallow-water equations

In this paper, we introduce a new locally implicit sonic point processing algorithm for one-dimensional shallow-water equations. The algorithm is based on transferring the shallow-water invariants along the characteristics around the sonic point, and it can be coupled with conservative-characteristic methods, which have problems modelling the transonic flows. For each sonic point, a system of two non-linear equations should be solved, which allows to use the proposed method with explicit methods for subsonic or supersonic flows without noticeable increase in calculation time. The important features of the algorithm include the second order of approximation in time and space and the property of time reversibility if monotonization procedures are disabled. Coupled with the CABARET scheme, the proposed method has been tested on several Riemann problems, including the Toro tests for transonic flows. The results have shown that the algorithm allows to obtain solutions with accurate transonic rarefaction and shock waves in both cases of wet and dry beds.

New Inventory of Dust Emission Sources in Central Asia and Northwestern China Derived From MODIS Imagery Using Dust Enhancement Technique

AbstractThe first inventory of dust emission sources in Central Asia and northwestern China (35–50°N, 50–100°E) derived from the twice daily MODIS imagery from 2003 to 2012 is presented. A high‐resolution (1 km) dust enhancement product was generated to produce maps of dust point sources (DPS), indicating geographical locations of the observed dust emissions, and gridded data sets of dust emission frequencies. About 13,500 DPS were detected over an area of ∼5 × 106 km2, however, their distribution was uneven. The highest frequency of DPS occurred in the northern and eastern Taklimakan, in the Aralkum, and in the regions, which were not widely reported in literature before, the Balkh delta in northern Afghanistan and the pre‐Aral, from the northern Caspian coast to the Betpak‐Dala desert in Kazakhstan. South of the Aral, DPS were mainly associated with fluvial features: drying lakes, dry river beds, alluvial deposits and agricultural activity which is closely linked to water availability in this arid region. In the pre‐Aral and Balkhash‐Junggar regions, land damaged by wildfire was the main source of dust. In China and eastern Kazakhstan dust emissions peaked in spring; in Central Asia and western Kazakhstan—in summer. The Aralkum was active throughout the year with a positive trend in emission frequency over the study period. Locations of DPS did not always correlate with high atmospheric optical depth (AOD) particularly west of the Aral and in the southern Taklimakan where few DPS were detected despite the high AOD values. This was attributed to dust transport from the upwind sources.

Numerical Simulation of Novel Hybrid Solid Desiccant Bed for Drying

Numerical Simulation of Novel Hybrid Solid Desiccant Bed for Drying

Assessment of the Influence of Evaporation and Evapotranspiration on the Volume of Sludge Accumulation in The Sludge Drying Beds

Assessment of the Influence of Evaporation and Evapotranspiration on the Volume of Sludge Accumulation in The Sludge Drying Beds

Drinking water salinity is associated with hypertension and hyperdilute urine among Daasanach pastoralists in Northern Kenya

Water salinity is a growing global environmental health concern. However, little is known about the relation between water salinity and chronic health outcomes in non-coastal, lean populations. Daasanach pastoralists living in northern Kenya traditionally rely on milk, yet are experiencing socioecological changes and have expressed concerns about the saltiness of their drinking water. Therefore, this cross-sectional study conducted water quality analyses to examine how water salinity, along with lifestyle factors like milk intake, was associated with hypertension (blood pressure BP ≥140 mm Hg systolic or ≥90 mm Hg diastolic) and hyperdilute urine (urine specific gravity <1.003 g/mL, indicative of altered kidney function). We collected health biomarkers and survey data from 226 non-pregnant adults (46.9% male) aged 18+ from 134 households in 2019 along with participant observations in 2020. The salinity (total concentration of all dissolved salts) of reported drinking water from hand-dug wells in dry river beds, boreholes, and a pond ranged from 120 to 520 mg/L. Water from Lake Turkana and standpipes, which was only periodically used for consumption when no other drinking sources are available, ranged from 1100 to 2300 mg/L. Multiple logistic regression models with standard errors clustered on households indicate that each additional 100 mg/L of drinking water salinity was associated with 45% (95% CI: 1.09–1.93, P = 0.010) increased odds of hypertension and 33% (95% CI: 0.97–1.83, P = 0.075) increased odds of hyperdilute urine adjusted for confounders. Results were robust to multiple specifications of the models and sensitivity analyses. Daily milk consumption was associated with 61–63% (P < 0.01) lower odds of both outcomes. This considerable protective effect of milk intake may be due to the high potassium, magnesium, and calcium contents or the protective lifestyle considerations of moving with livestock. Our study results demonstrate that drinking water salinity may have critical health implications for blood pressure and kidney function even among lean, active pastoralists.

ALIGN-CCUS: Results of the 18-Month Test with Aqueous AMP/PZ Solvent at the Pilot Plant at Niederaussem – Solvent Management, Emissions and Dynamic Behavior

After a 13,000-hour test campaign with aqueous 30 wt% MEA (2-aminoethanol) solvent at the CO2 capture pilot plant at Niederaussem, another long-term test was carried out as part of the ALING-CCUS project. This test ran for more than 12,275 hours with aqueous AMP/PZ (2-Amino-2-methyl-1-propanol/piperazine) solvent, named CESAR1 (3.0 molar AMP (~ 26.74 wt%) and 1.5 molar PZ (~ 12.92 wt. %)). A minimum specific reboiler duty of 2,970 MJ/tCO2 was identified for the capture plant operation with four active absorber beds (total 16 m packing height). Neither a lower desorber pressure of 1.5 bar(a), instead of 1.75 bar(a), nor a change of the different positions of intercooling had a significant effect on energy consumption. Reduction of the active packing height to three beds (i.e., 12 m), resulted in a moderately higher specific energy demand (+100 MJ/tCO2). Tests with CO2 capture rates between 90 and 98% showed only a small increase of the specific energy demand at 95% (+20 MJ/tCO2) and four active packings (98%: + 250 MJ/tCO2). The average solvent consumption of CESAR1 during 400 days of operation was 0.45 kg/tCO2 and is lower than for MEA if the phase of accelerated non-linear degradation of MEA is taken into account. CESAR1 follows a slow-progressing linear degradation behavior; neither a critical metal ion concentration threshold value could be found that triggers fast degradation nor a correlation between accumulated trace components or metal ion concentrations in the solvent and the degradation rate was observed. Highly transient tests were conducted to investigate the dynamic behavior of the capture plant and subsequently special settings were chosen to stimulate high emissions for the investigation of aerosol-based emissions, connected with performance tests of several emission mitigation measures: single water wash, double water wash, acid wash, dry bed, wet electric precipitator and flue gas pre-treatment. When applying the dry bed configuration, emissions of AMP between 15 - 20 mg/Nm3, PZ between 3 - 7 mg/Nm3, and NH3 below 3 mg/Nm3 were achieved.

Lift irrigation from dry river bed through shallow tubewell in Odisha

Lift irrigation from dry river bed through shallow tubewell in Odisha

Investigation of the end bearing load in pile group model in dry soil under horizontal excitation

A series of 94 laboratory tests were conducted to measure the response of pile foundation when subjected to dynamic loads. Eight tests were conducted on single pile in dry soil at relative density 30 % (loose) and 50 % (medium); 66 tests on group of piles with different spacings and patterns. All tests were carried out under operating frequencies 0.5, 1 and 2 Hz under horizontal shaking. All tests were achieved with one embedment ratio (L/d = 30). These tests were grouped in three different numbers of piles; 2 piles in row and line patterns, 3 piles and 4 piles; and three pile spacing ratios (s/d = 3, 4 and 5). The results of dry soil indicating the mechanism of dynamic response of piles and soil subjected to dynamic horizontal shaking include the variation and distribution of acceleration with time in different states of soil in addition to the vertical and horizontal displacements, end-bearing load, peak acceleration and the peak velocity of foundation. It was concluded that for a dry soil bed, the acceleration amplitudes increase with frequency for both soil relative densities (loose and medium) and different pile patterns (number; single or group and different spacing ratios s/d). The maximum acceleration in the foundation is lower than in the soil bed for all operating shaking frequencies, pile spacing ratios and soil states. The decreasing of the maximum acceleration recorded in the foundation as compared to that in the soil bed is between 10-100 % for loose and medium state of soil, and the decrease in loose state is more than in medium state. This means that there is damping effect or attenuation of vibration waves. The amplitudes of recorded acceleration in the pile cap are much higher than in the soil bed for single pile and pile group with different pile spacing ratios, also these amplitudes are increasing with increase of shaking frequency and relative density of the soil.

Granular impacts: how far the Boussinesq model can go?

A key problem on granular impacts deals with the determination of the mechanical response of the grains due to the impact of the intruder. This topic has been poorly addressed in the literature so far, a gap to which this study aims to contribute by measuring the pressure distribution at the bottom of a loose and dry sandy bed, impacted by a heavy sphere of fixed diameter. Exploring different bed thicknesses and intruder’s dropping height, we have found that the structure of this distribution is very similar to the Boussinesq model, initially proposed for a static point-force acting over an isotropic-elastic medium. This surprising result opens up many challenging questions that could help validate or refute this model in other scenarios.

Study on Sewage Sludge Drying System With Built-in Solar Drying Bed

In this paper, the renewable energy solar energy is used as the heat source. The combination of solar drying bed and traditional hot air drying can effectively reduce energy consumption and operation cost. The drying chamber is divided into three layers. The top air supply outlet supplies hot air, the middle layer places wet sludge, and the bottom layer uses hot water coil to dry the sludge. The whole drying process is a heat and mass transfer process with convective heat transfer and radiation heat transfer. After analysis and comparison with traditional energy drying, it is found that drying 97.5kg of sewage sludge will save 79% energy, save 12.84 kg of standard coal, reduce 32 kg of carbon dioxide and 1.284 kg of sulphur dioxide.

Changes in body temperature of critically ill patients submitted to bed bathing: a crossover clinical trial.

to compare tympanic and axillary body temperature values of critical patients before and after the traditional and dry bed bath. this is a randomized, open crossover clinical trial conducted with 50 adult critical patients. All patients received both types of bed bathing. The tympanic and axillary temperature values were measured at the beginning and end of the baths. The Wilcoxon test or paired Student's t test was used. elderly and male patients predominated. There was no significant difference between tympanic temperature medians measured during the traditional bed bath (p=0.707) and dry bath (p=0.101). Axillary temperature means reduced at the end of the baths (p=0.001), being 36.12ºC in the traditional bath and 35.92ºC in dry bath. bed bath, regardless of the method used, caused a reduction in critical patients' axillary temperature.

Numerical study of shallow-water equations using three explicit schemes - application to dam break flood wave

The numerical method to solve dam break problem on regular bathymetry was developed. Two cases of dam break wave propagation on wet and dry bottoms were selected to verify the numerical model elaborated. Three numerical schemes of Lax-Friedrichs, Adams-Bashforth and Adams-Bashforth-Adams-Moulton are applied to simulate this phenomenon using the 1D Saint-Venant equations. An artificial viscosity is added to these numerical schemes to provide stability and reduce numerical diffusion. This viscosity makes the numerical scheme robust (very powerful) for the simulation of this phenomenon. The results obtained show that these developed models are able to simulate dam break wave propagation process. The relative error in the L1 norm between the computed results and analytical solutions is calculated. The L1 norm indicates that the Adams-Bashforth-Adams-Moulton scheme has better accuracy than the other two schemes. It is shown that the technique used is simple, accurate, robust and stable for the simulation of the dam break wave propagation on wet and dry bed conditions.

Sludge Stabilization Process, Drying Depth and Polymeric Material Addition: Implication on Nitrogen Content, Selected Chemical Properties and Land Requirement in Sand Drying Beds

Drying beds are a simple and economical means to dewater municipal sludge and are widely used in places with a suitable climate for air-drying. However, research-based information on drying thickness/drying depth effects on nutrient content and land size requirements for sludge drying is scarce. In this study, aerobically digested (AeD), and anaerobically digested without polymer (AnDP0) and with polymer (AnDP1) sludge types were dried in sand drying beds at 5, 10, 15, 20 and 25 cm depths in South Africa. Measured nitrogen (N) fractions and other parameters were more strongly influenced by sludge types than by drying depth. Total N content followed the order of AeD &gt; AnDP1 &gt; AnDP0. Polymeric material addition tended to increase total and inorganic N content and reduce the length of sludge drying period and land size requirement. The study showed that larger land size is required to dry sludge at shallower depths, even though the sludge dried more quickly. Drying sludge at 15 cm was the best option across sludge types in winter, taking an average land area between 261 and 383 m2 over the fewest days of sludge drying, whereas in spring, drying at 20 to 25 cm depth was most favorable. The findings suggest that drying bed management can be based on land area requirements with little concern for biosolid quality changes. For wastewater treatment plants relying on drying in beds, adding polymeric materials may be beneficial where land area for drying beds is limited, but not otherwise. Therefore, land availability is critical in decision making for sustainable sludge drying thickness.