Bed Dryer Research Articles

Assessment of aerosol particles using a new index

Dry beds of lakes and surrounding areas play an important role in dust production. This work develops a new index called Aerosol Type Detection Index using the Extinction Coefficient and Depolarization Ratio. The developed index shows values between zero and 0.15 for desert dust and -0.3 to zero for polluted desert dust particles in two regions including the Aral Sea in Central Asia and Hamoun Lake in Sistan, Iran. Although the dried beds of these lakes are susceptible to strong winds, wind speed profiles show that north of the Aral Sea and northwest of Hamoun Lake can be dust storm sources in these regions.

Método sobol para análise de sensibilidade do modelo hydrus na simulação de infiltração de água em depósito aluvionar no semiárido brasileiro

ABSTRACT Simulation of water flow in the soil in semiarid regions is fundamental for managing scarce water resources. Aiming for more accurate results, the sensitivity analysis (SA) of the hydrodynamic parameters involved in the simulations is very relevant. This study aims to evaluate the influence of hydrodynamic parameters on the hydrological response of an alluvial deposit in the dry bed of the Capibaribe River using the Hydrus-1D. A global sensitivity analysis method proposed by Sobol was chosen to evaluate the sensitivity of the soil water infiltration curve. A convergence analysis was carried out to investigate the evolution of the indices with increasing sample size. Values of the sensitivity indices showed gross variations at the beginning of the simulations for the different parameters, but they converged within the set of 10,000 samples. For parameters whose sensitivity indices are closer to 0, it is noted that 1,000 samples (14,000 simulations) were sufficient for the index to converge to their final value. The total and first-order sensitivity index calculated with 10,000 samples present the parameters n and Ks as the most important, being expressly more influential than the others.

Discussion of “Experimental investigation into the boundary layer structure near the tip of a dam-break wave on a dry, rough and horizontal bed” by Beibei Xu, Rui Shi, Peter Nielsen, Zheng Gong

Discussion of “Experimental investigation into the boundary layer structure near the tip of a dam-break wave on a dry, rough and horizontal bed” by Beibei Xu, Rui Shi, Peter Nielsen, Zheng Gong

Karakteristik Pengeringan Rempah Daun Menggunakan Fluidized Bed Drier dan Tray Drier

Bay leaves (Sygygium polyanthum), kaffir lime leaves (Citrus hystrix) and pandan leaves (Pandanus amaryllifolius) are herb leaves with unique aroma that are often added to dishes to strengthen and enrich the taste. The high demand of the leaves has prompted efforts to make them easy to distribute and shelf stable. Drying can increase the shelf life of these leaves with acceptable quality. The objectives of the research were to determine drying models for these leaves using two types of driers and to determine the panelist's preference for the dried and rehydrated leaves. These herb leaves are fresh-picked from the tree, cleaned and dried using the two different driers, i.e. fluidized bed drier (temperature 40-42°C) and tray drier (temperature 58-61°C). The leaves were weighed every 15 minutes until they reached a constant weight. Fresh leaves and dry leaves were photographed. The drying kinetics of both types of driers were checked with the Lewis model and Page model. Panelist preference test was carried out on dry leaves and leaves that had been rehydrated using hot water. The results showed that drying with a tray drier was able to dry faster than that with a fluidized bed drier. The Page drying model is more suitable to describe the drying conditions than the Lewis drying model. Panelists preferred dry and rehydrated herb leaves obtained from fluidized bed drying.

Data on the pioneer vegetation of the Lake Velence

Lake Velence is one of Hungary's largest saline lakes. Part of its natural dynamics is that certain parts of the lake bed regularly dry out, providing pioneer surfaces suitable for the emergence of plants of the mudflats and drying (saline) ponds. During the particularly dry year of 2022, the water level was per­manently and significantly low, allowing to study the vegetation of the dry lake bed. In the first half of the last century, the natural vegetation of the lakeshore (including salt steppes) was studied, but there are very few records of the pioneer species of the lake bed. The salt steppes around the lake have now largely declined, but due to low water levels, some of their characteristic species are still present in the lake bed (though, usually in low number of individuals). Examples include Crypsis aculeata, Cyperus pannonicus, Suaeda pannonica, the once abundant Suaeda prostrata, and the previously rare Crypsis schoenoides and Spergularia salina. Spergularia maritima was once widespread but currently not found in the lake bed. Although, Schoenoplectus litoralis is not a member of the ephemeral vegetation, but is a characteristic plant of the littoral zone of Lake Velence. This species probably appeared therein the middle of the last century and is currently spreading.

Causes of Lamb Mortality in the Lacaune Sheep Breed in Iran

Background: Neonatal mortality is a significant multifactorial problem that affects flock productivity. Different infectious and non-infectious factors have been attributed to lamb losses. The objective of the present study was to identify the major causes of neonatal mortality.
 Methods: In a 3-months period, 114 Lacaune breed lambs died of which 52 animals were lost with clinical signs of infection. Heart and lung samples were collected and transmitted to the laboratory. Microbiological cultures following biochemical tests were conducted to identify bacterial infection of the lambs.
 Results: A total of 52 out of 114 lambs (45.6%) were infected with bacteria. The bacteria including Escherichia coli (30.8%), Proteus mirabilis (19.2%), Pasteurella multocida (1.5%), Corynebacterium pseudotuberculosis (7.7%), Mannheimia haemolytica (3.9%), Staphylococcus epidermidis (1.9%) were isolated. The role of the identified pathogens was more significant in lamb death compared to noninfection causes. Diarrhea was the most euoitcefni disease followed by septicemia and pneumonia. Escherichia coli was isolated significantly more than other bacterial agents (30.8%).
 Conclusion: The present findings showed Escherichia coli as the most common pathogen leading to lamb losses in the first two weeks of life. ciieigyeiuet practice which encompasses both environment and milking equipment, periodical flaming, and providing dry and clean bedding can dramatically decrease the infection among uiobfeu animals. Reduction of the birth density and avoiding synchronization until the expert and labor capacity has reached the optimal level are necessary actions to reduce infectious diseases.

A Finite Volume Method for a 2D Dam-Break Simulation on a Wet Bed Using a Modified HLLC Scheme

This study proposes a numerical model for depth-averaged Reynolds equations (shallow-water equations) to investigate a dam-break problem, based upon a two-dimensional (2D) second-order upwind cell-centre finite volume method. The transportation terms were modelled using a modified approximate HLLC Riemann solver with the first-order accuracy. The proposed 2D model was assessed and validated through experimental data and analytical solutions for several dam-break cases on a wet and dry bed. The results showed that the error values of the model are lower than those of existing numerical methods at different points. Our findings also revealed that the dimensionless error parameters decrease as the wave propagates downstream. In general, the new model can model the dam-break problem and captures the shock wave superbly.

Trajectory analysis of central Sonoran Desert dust storms

Dust storms are a major cause of central Sonoran Desert weather fatalities. Through back-trajectory analysis of North American Monsoon dust storms in central Sonoran Desert of the United States. This study is specific to central Arizona (USA) from 2009 to 2022 using the HYSPLIT model. Our findings have shown that dust storms originate from southerly or near-southerly regions. The dust storms displaying the highest concentrations of particulates show a preference to originate from the southwest. This coincides with the development of a 500 hPa ridge to the east of the study area. The highest concentration storms’ back-trajectories display the lowest heights above the ground. Given their southwestern origin, these storms travel upslope along the seasonally dry river beds of the Gila River and its tributaries. Weaker dust storms originate over a wider area with a shift to a southerly direction. Such origination indicates that weaker dust storms are traveling downslope through the washes and channels of the dry Santa Cruz River. As dust concentrations drop, storm direction drifts east and dust height is suspended higher. This paper highlights the spatial variations in central Arizona dust storms, showing the likeliest paths of the strongest events and assists in identifying aeolian dust origins.

Estimation of fine sediment stocks in gravel bed rivers including the sand fraction

ABSTRACTFine sediment stored in the gravel bed is an important component of river systems. Current field protocols usually allow evaluation of the silt–clay fraction of fine sediment stocks only and neglect the sand fraction. This study proposes a new protocol to quantify fine sediment stocks, including the sand fraction inside the gravel bed matrix. Fine sediment stocks were sampled within patches of 0.30 m × 0.30 m on the dry gravel bed surface, separating the surface layer and the subsurface layer. The grain‐size distribution of the samples was obtained by field sieving (10 mm, 2 mm, 500 μm and 100 μm) over a bucket, using a known volume of water. The mass of the fraction below 100 μm was measured based on the concentration within the bucket. The local stocks were then integrated over the whole river reach by assigning local stocks to facies, in which fine sediment stocks were assumed to be homogeneously distributed. The methodology was applied to a 1 km long reach of the River Galabre (Southern French Alps), characterized by significant fine sediment stocks and upstream sediment input. Results from local measurements show a large amount of sand in both surface and subsurface layers. The quantity of sand can reach up to three times the quantity of silt–clay. An estimation of porosity showed that fine material may play an important role in structuring the bed, since porosity increases with increasing fine sediment content. The potential fine sediment stock that can be resuspended due to channel migration is found to be of the same order of magnitude as the sediment budget estimated from the measured flux in the upstream hydrometric station of the studied reach.

Erosion and Transport of Dry Soil Bed by Collisional Granular Flow: Insights From a Combined Experimental–Numerical Investigation

AbstractCollision‐induced stresses on soil beds under granular geophysical flows have been demonstrated to be highly erosive. However, it remains mostly elusive as to how a collisional granular flow erodes and transports soil bed material. This paper presents a combined experimental and numerical investigation into the mechanisms underlying collision‐induced erosion and transport of dry soil beds. A series of flume experiments are conducted where collisional granular flows erode dry sand beds under varied conditions. The experiments are then back‐analyzed using a hybrid continuum–discrete simulator to gain physical insight into the erosion and transport processes. Results show that the key mechanism of collision‐induced erosion and transport is the retexturing of the soil bed surface. This implies that bed morphology, which has often been overlooked in mobility and hazard assessments, has profound effects on erosion and transport potential. Further, contrary to most existing models that assume all the eroded bed volume is carried away by granular flow, it is found that only up to 80% of the eroded material is transported. Also found is that the collisional stresses of the monodisperse grains in this study follow the Pareto distribution in which 80% of differences in the outcomes are due to 20% of causes. This finding suggests that there is measurable certainness in a seemingly random process of coarse grain collisions with an erodible soil bed.

Exposure of volunteers to microgravity by dry immersion bed over 21 days results in gene expression changes and adaptation of T cells.

The next steps of deep space exploration are manned missions to Moon and Mars. For safe space missions for crew members, it is important to understand the impact of space flight on the immune system. We studied the effects of 21 days dry immersion (DI) exposure on the transcriptomes of T cells isolated from blood samples of eight healthy volunteers. Samples were collected 7 days before DI, at day 7, 14, and 21 during DI, and 7 days after DI. RNA sequencing of CD3+ T cells revealed transcriptional alterations across all time points, with most changes occurring 14 days after DI exposure. At day 21, T cells showed evidence of adaptation with a transcriptional profile resembling that of 7 days before DI. At 7 days after DI, T cells again changed their transcriptional profile. These data suggest that T cells adapt by rewiring their transcriptomes in response to simulated weightlessness and that remodeling cues persist when reexposed to normal gravity.

Effect of the surface water content on dry saltation cloud dynamics: A wind tunnel simulation with particle tracking velocimetry

AbstractThe mass transport rate of wind‐borne particles, and indeed the fluid stress required for their entrainment, is strongly governed by inter‐particle cohesion arising from water retained through adsorption and capillary force. This paper reports on a series of wind tunnel experiments in which high‐speed photography was used to record the motion of dry sand particles as they impinged on test beds of systematically varied target gravimetric pore water content (0% ≤ W ≤ 10%). The wind friction velocity was preset to 0.33 m s−1, sufficient to maintain a saltation cloud above an upwind strip of dry sand, which then was blown over the wetted surface. Discrete particle trajectories were identified in the camera images using expected particle area searching–particle tracking velocimetry (EPAS‐PTV). Adding progressively more water produced an exponential decrease in the normalized particle number density over the test surface. The largest response was achieved by wetting the bed surface to just 2%. To reduce the number of particles by a further 40%, it was necessary to add eight times more water, signifying a diminishing return regarding water use. Relative to particles either rebounding or splashed from a dry bed, the total particle velocity increased incrementally by a factor between 1.5 and 2 with increasing water content. Increasing amounts of pore water were associated with progressively higher saltation trajectories, reaching a plateau beyond W ~8%. The spatio‐temporal adjustment in the sand cloud was observed to be extremely rapid. There is no consensus in the literature on how to measure the water content that effectively governs aeolian transport. In this study, all approaches to sampling W produced strong correlation (R2 ≥ 0.85). Sampling the topmost grains, however, provided the most accurate prediction of the normalized number density over the full range of water content.

Oxygen Stream Management in a CECE Process

In the combined electrolysis and catalytic exchange (CECE) process, the electrolyzer produces both hydrogen and oxygen streams. Hydrogen is typically fed to the bottom of the liquid-phase catalytic exchange column. The oxygen stream, however, is processed and afterward is either fed back to the trickle bed recombiner in heavy water detritiation or released to the exhaust stack in light water detritiation. This paper discusses the handling of the oxygen stream both in heavy and light water detritiation CECE processes. Oxygen leaving the electrolyzer has a trace amount of tritium gas in it as well as water vapor (due to diffusion across the membrane). Trace tritium is converted to vapor using a catalytic converter and then either scrubbed using an oxygen vapor scrubber or captured in a dryer bed. This study analyzes and compares the different options for handling the oxygen stream in a CECE process.

APPLICATION OF A GAS-SOLID FLUIDISED BED SEPARATOR FOR ALUMINIUM-COPPER SCRAP RECYCLING

The EUbs circular economy concept necessitates the recycling of material streams used once or multiple times into the productionb consumption cycle again and again. The commonly known problem b that the number of recycling cycles of plastics is limited drives the economy towards metal usage again, because metal recycling cycles are limitless. Therefore, the efficient and economic separation of mixed aluminium and copper scraps in the 30b100 mm particle size range is an important issue for our society. In this study fundamental and applied research was carried out for the application of a gas-solid fluidised bed separator for aluminium-copper scrap recycling. A laboratory scale aero-suspension dense media separator was developed. Fundamental fluidisation experiments were carried out with this device and a powder rheometer. Afterwards pilot-scale and later industrial-scale separators were designed and built. The results indicate that the well-known Ergun fluidisation model can be the basis of a new process engineering design method for sizing dry fluidised bed separators.

POTENSI PEMANFAATAN LUMPUR DARI PROSES PENGOLAHAN AIR LIMBAH INDUSTRI

The liquid waste treatment process will produce another by-product, namely sludge or sludge. Sludge from WWTP is managed in a Sludge Drying Bed (SDB) unit with a drying system. utilization of sludge into a valuable product is an effort to reduce sludge discharged into the environment. The sludge can be utilized one of them as fuel in the form of briquettes. Utilization of sludge as compost is an alternative that can be done as an effort to manage the environment and has humus material and nutrient content. As well as mud as an alternative to providing nutrients in ultisol soil. Another use of sludge waste is to utilize toothpaste factory sludge as a raw material for brick making, because of its characteristics it contains SiO2 and CaO.

Organic cultivation of mint under different amounts of hairy woodrose (Merremia aegyptia L.) and harvesting times

This experiment was conducted to evaluate the possibility of organic cultivation of mint under different amounts of hairy woodrose and harvesting times. The experimental design was randomized complete blocks with the treatments arranged in 4 x 3 factorial scheme with three replicates. The first factor consisted of four amounts of hairy woodrose (0.0, 0.5, 1.0 and 1.5 kg m-2 of dry beds) and the second factor, corresponded to three harvest bunches (30; 60 and 90 days after transplanting). The cultivar "Mentha piperita" was used as mint crop. The evaluated characteristics were the following: biomass height, biomass production, number of sauces, dry mass, oil content and yield. There was interaction between the factors-treatments for yield, number of bunches and oil content. The best productive performance of the mint was obtained in the amount of 1.0 kg/m2 of hairy woodrose incorporated into the soil at 60 days after mint transplanting (AMT). Hairy woodrose proved to be efficient as a green manuring in the mint crop.

Design of a Batik Coloring Waste Treatment Tool Using the Electrocoagulation Method with a Capacity of 50 Liters

Batik coloring still uses synthetic dyes, so the disposal of coloring waste should not be careless. Most batik craftsmen process their batik waste by settling the waste liquid for a long time. The process is very ineffective. The purpose of this research is to design a batik processing tool that is cheap and effective. The research method uses the electrocoagulation method. The electrocoagulation method is an electrochemical water treatment. The design of this batik waste treatment tool consists of five parts including: (1) Electrocoagulation Tub, (2) Skimmer, (3) Electrode, (4) Sand Filter, and (5) Studge Drying Bed. This tool works with 900 watts of power with an output of 20-40 volts DC. The capacity of liquid waste is 50 liters. Duration of waste treatment for 2 hours. The electrocoagulation method is able to reduce the values of BOD5, COD, TSS, and TDS in batik dye waste. The pH of wastewater which is still high can be reduced by giving alum.

Radial basis function-based differential quadrature for dam break problems

This study presents a new approach for simulating dam break flows with the two-dimensional shallow water equations (SWE), incorporating wet and dry beds, as well as irregular and frictional topography. The proposed method employs local radial basis function-based differential quadrature (LRBF-DQM) meshless techniques for space-derivative operators, while utilizing an explicit first-order finite difference scheme for the temporal derivatives. To evaluate the effectiveness of the proposed method, several two-dimensional numerical experiments were conducted to simulate the flow resulting from a dam break. The numerical experiments were specifically designed to assess the performance of the suggested approach and compare it against existing benchmarks. The results demonstrate the promising accuracy of the LRBF-DQM meshless technique in solving SWE problems, specifically in simulating dam break flows, despite the inherent complexities of these problems. The method is easy to program and mesh-free, but requires careful selection of suitable shape parameters, as with previous RBF applications.

Transient Bedload Transport During Flashflood Bores in a Desert Gravel‐Bed Channel

AbstractEvidence of the effect of unsteady flow on bedload sediment transport is meager, particularly in desert rivers, despite its scientific, environmental and engineering importance. Our study of the phenomenon was conducted in Nahal Eshtemoa, Israel, an ephemeral river located in a semi‐arid area and subjected to flash floods. During 4 years, we monitored bedload transport and contemporaneous hydraulics, focusing on two intervals during which flow changed most rapidly: (a) the arrival of flood bores over dry river beds and (b) the propagation of subsequent bores over flowing water. Monitoring involved deployment of plate microphones, video cameras, surface velocity radar and a 3D velocimeter, enabling synchronized and unique data acquisition at high temporal resolution. We hypothesized that turbulence would be considerably elevated during the arrival of a flood bore and that this would induce transient entrainment of bedload. Our results demonstrate that bedload is indeed transported by the bore front and ceases soon after the arrival of most bores, even though water depth continues to rise. Bores arriving on a dry river bed usually generate higher bedload fluxes than bores advancing over flowing water. Elevated values of shear stress, turbulent kinetic energy and water‐surface slope occur as a bore impinges but then decrease. This is likely to be the explanation for high transient rates of bedload transport. Once the threshold depth previously determined as inducing continuous bedload motion is attained (≈40 cm), transport rates rise considerably relative to those associated with the bores.

Numerical modeling of liquid spills from the damaged container and collision of two rising bubbles in partially filled enclosure using modified Volume-Of-Fluid (VOF) method

In the present work, two crucial shortcomings associated with Volume-Of-Fluid (VOF) model namely: (1) spurious interface smearing arising from false-diffusion errors, and (2) non-physical velocity fluctuation across the physical discontinuities, are systematically addressed, aiming to establish a unique methodological foundation and guidelines for the enhancement of interface-capturing techniques in handling multi-fluid flows. To accomplish this objective, first, a novel third-order bounded convection scheme is derived based on the Normalized Variable Diagram and Total Variation Diminishing concepts (NVD-TVD) and is then applied for the discretization of the volume-fraction equation. To cope with the instability issue induced by pressure fluctuation, the standard version of the implicit non-iterative PISO algorithm is first modified by incorporating the third pressure-correction step into the algorithm and is then utilized for the treatment of the pressure-velocity coupling. A feasibility and applicability of the proposed modifications in dealing with violent free-surface and multi-fluid flows are demonstrated against the five different challenging benchmark cases including two-dimensional dam-break flow over the dry bed, oil spill from the damaged container, single bubble rising, merging of two rising bubbles and two-fluid Rayleigh-Taylor Instability problems. The comparison of the obtained results with previously published literatures vividly corroborates the robustness and versatility of the modified VOF model in handling multi-fluid flows involving interface coalescence and breakup events. In the last staged, three new benchmark solutions namely (1) coalescence of two consecutive bubbles inside the partially filled enclosure, (2) two-dimensional three-fluid Rayleigh-Taylor Instability, and (3) oil/water spilling from the damaged tank are analyzed using the verified VOF method, aiming to provide a high-quality validation data for CFD simulations.