Dry Out Research Articles

Drying out fish ponds, for an entire growth season, as an agroecological practice: maintaining primary producers for fish production and biodiversity conservation.

Agroecology largely focusses on terrestrial agroecosystems, but it can also be applied to fish farming. Indeed, ponds are typically used for fish production in Europe, but are also important reservoirs of biodiversity. Numerous studies demonstrate that both fish production and biodiversity are strongly determined by human management. One key practice in extensive fish farming, although more rare in Europe, is to dry out ponds. They are left dry for a complete year after several years of fish production. However, the extent to which this practice affects the functioning of the ecosystem, its biodiversity and fish production remain unclear. We investigated data from 85 fish ponds in the Dombes region, France, sampled between 2007 and 2014. We related variation in key abiotic characteristics to the time since last dry out. The dataset included organic matter content in pond sediments and concentrations of inorganic nitrogen and phosphorus in the water column, and biotic components such as macrophytes cover and richness, phytoplankton concentration and richness, macroinvertebrates density, and fish yield. Our results show that drying out facilitates the mineralization of organic matter in sediments and results in higher concentrations of inorganic nitrogen in the water column. Macrophytes cover is highest during the first year after drying out, and gradually declines after at the expense of increasing phytoplankton concentration. The diversity of both is highest in the first year after drying out and declines rapidly, especially for macrophytes. Fish yield is at its maximum in the second year. Drying out fish ponds appears to be an important agroecological practice in extensive fish farming with an application every three to four years. By nutrient recycling, this practice has a positive impact on the balance between primary producers and indirectly on the whole food web during two years. It optimizes fish production and allows biodiversity conservation.

The compression deformation and particles removal of PVA brushes during the post-CMP cleaning process

Abstract In advanced wafer manufacturing processes, a wet cleaning system (wet in dry out) integrated with chemical mechanical polishing equipment is the primary form of post-chemical-mechanical polishing (CMP) cleaning. This pioneering study addresses the quantitative description of the contact between a polyvinyl alcohol (PVA) sponge brush and the wafer surface and establishes a relationship between the compression deformation as a function of the pressure on the wafer surface to achieve precise control of the contact between the brush and the wafer. The physical properties of the three types of PVA sponge brushes, namely, porosity, saturated water absorption, and pore change rate, were analyzed, and the effect of particle removal was explored. Finally, the effect of the brush on removing the residual polishing liquid from the wafer surface under different compression deformation conditions was studied, and its internal mechanism was explained. A ‘√’ curve was observed between the compression deformation (stress) and particle removal effect. When the compression deformation (stress) is 0.5 mm (35.11 g), the 26 nm particles on the wafer surface after post-CMP cleaning can reach less than 10ea.

First record of leaf miner, Phyllocnistis unipunctella (Stephens, 1834) (Lepidoptera, Gracillariidae) infesting Populus deltoides Marsh (Salicaceae) in Jammu and Kashmir, India

The study reports infestation of leaf miner Phyllocnistis unipunctella (Stephens, 1834) (Lepidoptera, Gracillariidae) on Populus deltoides Marsh (Salicaceae) in the UT of Jammu and Kashmir, India. The serpentine mining of leaves by larvae caused the leaves to dry out and turn brown, which lead to premature leaf drop, especially in severe infestations. Large populations rendered a silvery hue to the appearance of infested poplars when viewed from a distance. Pupation occurred inside the mine within a silken cell. Adults emerged after a period of 10-14 days. The infestation by this moth on poplars in the field was observed from the month of July to September.

Flow boiling characteristics of HFE-7000 in high aspect ratio microchannels with the effect of flow orientation

The aim of the present experimental study is to investigate the flow boiling characteristics in a high aspect ratio microchannel for two different channel orientations. Hydrofluoroether 7000 (HFE-7000) flowing within a rectangular glass microchannel (with a hydraulic diameter of 909 μm and a width-to-height aspect ratio of 10) coated with a tantalum layer to provide uniform heating along the channel was the configuration investigated. The data were recorded for mass flux of 14 − 42 kg m−2 s−1, while the heat flux was varied between 3.5 and 24.3kWm−2 under horizontal and vertical upward flow. Analysis of the experimental data reveals that thermal performance is influenced by both mass and heat fluxes, as well as flow orientation, and these are presented and discussed. The wall temperature mapping and heat transfer coefficient analysis showed that for low mass flow cases, the dry out occurs at a lower heat flux and for either flow orientation. At medium and higher heat fluxes, though, it is found that a horizontal flow produces dry out events more easily compared to vertical upward flow. The observed phenomenon during flow boiling also shows the importance of nucleate boiling and thin film evaporation on the heat transfer performance. In addition, pressure fluctuations during flow boiling were also recorded. A Fourier transform analysis of pressure fluctuations data showed that vertical upward flow produces a higher dominant frequency than horizontal flow. Finally, the analysis of thermal characteristics and pressure fluctuations can provide further insights into the design of devices where flow orientation plays a major role.

Potential of Dried Red Palm Leaves as Sheet Interior Material

Red palm leaves only used as ornamental plants in the yard around the house, as they dry out and fall to the ground, they become unusable rubbish. Research has shown that red palm leaves are of high fiber quality. Red palm leaves are a good choice for furniture because they are durable and appealing in addition to having excellent fiber content and the level of quality[1]. This study seeks to serve as a resource of knowledge and a substitute for furniture craftsmen who want to utilize furniture mats made from leaf waste instead of wood or plastic. It can reduce the usage of inorganic resources that can harm the environment and nature through the use of materials from biological waste. Preparing tools and supplies, washing, drying, and shaping furniture mats are all steps in the process of creating organic furniture mats. Two parameters, namely the width of the palm leaf sheet with a size range of 2 cm and 3 cm, were identified as influences in this investigation [2]. The mechanical qualities of the red palm leaves used as the base for the organic furniture were tested, along with the leaves’ biodegradability and water permeability [3]. This is going to be a solution that may reduce waste from dried red palm tree leaves and work as a platform for furniture instead of using materials like wood and plastic that are bad for the environment.

Losses in fishery ecosystem services of the Dnipro river Delta and the Kakhovske reservoir area caused by military actions in Ukraine

We studied the development of commercial and recreational fishing on the Kakhovske Reservoir (aka Kakhovka) and the Dnipro (aka Dnieper) River lowlands in 2020–2023. The fish assemblage of the Kakhovske Reservoir is under consideration for the period 1956–2021. The dynamics of the fish population transformation, species extinction, and the emergence of new invasive species are given. The losses in Kakhovske Reservoir’s ecosystem services as a result of the Kakhovska Hydroelectric Power Plant’s (HPP) Dam explosion in June 2023 are analyzed. The states and prospects for local recreational and commercial fishing development are assessed. By field research and monitoring observations of the Kakhovske Reservoir and the Dnipro River lowland using the Earth remote sensing data, it was established that 2 months after the accident, the area of the remained reservoir water surface was ∼430 km2 (about 19% of the initial, including the restored Dnipro River bed). The newly formed shallow waterbodies, which do not have a water connection between each other, occupy an area of about 300 km2. These areas continue to dry out, shrink, and become overgrown with vegetation. The draining of the Kakhovske Reservoir caused an ecological disaster for about 40 species and subspecies of fish. The total monetary losses of commercial fishing are about $5.5 million annually. Losses in fishery from the vanishing of spawning grounds are estimated at 20,000 tons of fish resources (∼$40 million). The negative consequences of the loss of the Kakhovske Reservoir aquatic ecosystems will affect the socio-economic development of the entire South of Ukraine for a long time. Among the major ecosystem services lost is the cessation of water supply. Ukraine’s priority issues are the post-war rehabilitation of the country, its degraded lands, territories, and water areas, and ensuring water and food security. One of the urgent problems will be the feasibility of reconstruction of the Kakhovska HPP’s Dam and restoration of the Reservoir, renovation of water supply, fishery, navigation, energy, and recreation. Biodiversity is a basis for the efficient and sustainable ecosystem functions that provide many ecosystem services, and it should be considered for the post-war recovery and development of Ukraine.

Numerical study of Two-Phase flow behavior during dryout in a Two-Phase closed thermosyphon under thermal boundary conditions

This paper presents a two-dimensional axisymmetric two-phase closed thermosyphon (TPCT) model filled with R-134a refrigerant using the Volume of Fluid (VOF) method, Lee model, and Continuum Surface Force (CSF) method within Computational Fluid Dynamics (CFD) and simulates the flow characteristics inside the TPCT during the occurrence of dry out. Specifically, it discusses the two-phase flow in the condensation and evaporation sections when dry out occurs. The results indicate that the condensation section exhibits varying forms of vapor–liquid interface waves at different times. Phenomena such as liquid carryover and entrainment become increasingly prominent over time, contributing significantly to refrigerant blockages and dryout in the evaporation section. The mechanism behind dryout in the evaporation section is revealed to be the result of the initially continuous falling film being disrupted by fluctuations in the liquid–vapor interface, leading to the premature drying of thin liquid films in the troughs of these waves.

Inventarisasi Kearifan Lokal Etnis Karo Dalam Pembuatan Minyak Karo Desa Namo Ukur Kecamatan Sei Bingai Kabupaten Langkat

Research on the study of Minyak Karo ethnobotany aims to determine the types of plants that are the raw material for making Minyak Karo and its utilization. The method used in the study is a qualitative descriptive method with data collection techniques carried out through an emic approach and an ethical approach to the interview method with producers of Minyak Karo. The results obtained in this study are 42 species from 24 families which are used as ingredients in the production of Minyak Karo. Zingiberaceae is the type most widely used in these herbs. Plan tparts used are leaves (16 species), rhizomes (7 species), roots (6 species), seeds (5 species),fruit (4 species), flowers and tubers (2 species each), and stems (1 species). Benefits of Minyak Karo treat aches, treat colds, reduce heat / fever, heal wounds, dry out and treat sunburn, treat itching, strengthen bones in infants, treat lumbago, treat rheumatism, treat sprains, treat body aches, and treat muscle cramps. Minyak Karo is an external medicine so that its use is enough by way of being rubbed applied or massaged.

DEVELOPMENT OF HEAT EXCHANGER WITH TWO-PASS DIVERGING MICROCHANNELS FOR EVAPORATION COOLING SYSTEMS

This study developed a two-pass diverging microchannel heat exchanger to avoid flow reversal and partial dry out of HFC-245fa flow boiling in the evaporation cooling systems. It is aimed to improve the diverging microchannel heat exchangers designed by previous studies and to effectively accommodate diverging channels on a limited heating base surface. The test results showed that the maximum heat transfer coefficients in a diverging channel heat exchanger were as much as 20% higher than those in straight channel heat exchanger, while the maximum partial dry-out heat flux is 42% higher in diverging channel heat exchanger. There is no significant difference for the pressure drops in two heat exchangers at low heat fluxes before it reached the partial dry-out condition. For higher flux, the pressure drops in straight channels were higher than those in divergent channels while partial dry out. It is concluded that the two-pass diverging channel design provided higher maximum heat transfer coefficients and higher maximum heat fluxes with lower penalties of pressure drops. It could be a good design to replace the conventional straight channel heat exchanger for evaporation cooling systems.

FLOW BOILING HEAT TRANSFER IN MICROCHANNEL HEAT EXCHANGERS WITH MICRO POROUS COATING SURFACE

This study experimentally investigated the heat transfer and pressure drop performance of refrigerant HFC-245fa flow boiling in microchannel heat exchangers with and without microporous coating. The flow boiling heat transfer performance at various mass fluxes, heating rate, exit vapor qualities, and surface coating thickness was compared. The test results showed that the 52 μm coating thickness porous surface exhibited 65-148% higher heat transfer performance than the smooth surface, while the 98 μm microporous coating surface showed a lower improvement of 41-90% at various mass fluxes. Partial dry out was observed at high and moderate mass fluxes on both smooth and porous coating channels. It happened at lower exit vapor qualities in microporous coating channels than that in smooth channels. The partial dry-out exit vapor qualities increased with decreasing mass fluxes. For the lowest mass flux, because of the low heat flux and low nucleation suppression, no significant partial dry out was investigated. The pressure drops in microporous coating channels were around 25-47% higher than those in smooth channels. There was no significant influence of microporous coating layer thickness on flow boiling pressures drops.

Irrigation practices affect relationship between reduced nitrogen fertilizer use and improvement of river and groundwater chemistry

In the last decades, the intensification of agricultural practices has deeply altered nitrogen (N) and water cycles. Climate change and drought events are expected to further increase the human impacts on the hydrological and biogeochemical cycles, and these impacts are gaining the attention of the scientific community. Here we show how the Chiese River watershed (Lombardy Region, Italy) represents an interesting opportunity to analyse the effects of traditional irrigation practices on N contamination in the context of water scarcity. During summer, flood irrigation is mostly sustained by groundwater withdrawal. Additional water withdrawals from the river contribute to the dry out of the Chiese River. The use of wells for irrigation over permeable and fertilized soils and the percolation of nitrate (NO3-) from the vadose zone to groundwater result in the accumulation of NO3- in groundwater and limited N losses via denitrification due to dominant oxic conditions. These practices contrast other measures targeting the reduction of N excess over arable land. In the Chiese River watershed, the N surplus from Soil System Budget calculations decreased by 43% since the early 2000 s but NO3- concentration in groundwater remained high and stable (up to 98.0 mg NO3- L−1). The dried-out Chiese River gains groundwater and NO3- concentration at the river mouth approaches 32.2 mg NO3- L−1. Our results suggest how the mismanagement of the watershed (overabundant fertilization and flood irrigation using groundwater) increases the N concentration both in the river and groundwater, leading to the violation of both Nitrate and Water Framework directives. We anticipate our assay to be a starting point for the conversion of the northern Po Plain to more efficient irrigation and fertilization practices to contrast severe droughts driven by climate change like the one who struck the Po Plain in summer 2022.

Drying out fish ponds, for an entire growth season, as an agroecological practice: maintaining primary producers for fish production and biodiversity conservation

Agroecology largely focusses on terrestrial agroecosystems, but it can also be applied to fish farming. Indeed, ponds are typically used for fish production in Europe, but are also important reservoirs of biodiversity. Numerous studies demonstrate that both fish production and biodiversity are strongly determined by human management. One key practice in extensive fish farming, although more rare in Europe, is to dry out ponds. They are left dry for a complete year after several years of fish production. However, the extent to which this practice affects the functioning of the ecosystem, its biodiversity and fish production remain unclear. We investigated data from 85 fish ponds in the Dombes region, France, sampled between 2007 and 2014. We related variation in key abiotic characteristics to the time since last dry out. The dataset included organic matter content in pond sediments and concentrations of inorganic nitrogen and phosphorus in the water column, and biotic components such as macrophytes cover and richness, phytoplankton concentration and richness, macroinvertebrates density, and fish yield. Our results show that drying out facilitates the mineralization of organic matter in sediments and results in higher concentrations of inorganic nitrogen in the water column. Macrophytes cover is highest during the first year after drying out, and gradually declines after at the expense of increasing phytoplankton concentration. The diversity of both is highest in the first year after drying out and declines rapidly, especially for macrophytes. Fish yield is at its maximum in the second year. Drying out fish ponds appears to be an important agroecological practice in extensive fish farming with an application every three to four years. By nutrient recycling, this practice has a positive impact on the balance between primary producers and indirectly on the whole food web during two years. It optimizes fish production and allows biodiversity conservation.

Experimental investigation of thermal behavior of overfilled sodium heat pipe

Operating limitations model of heat pipes are difficult to evaluate the effect of the charging amount of working fluid, which is one of the crucial factors in heat pipe performance of startup and maximum heat transfer. To reduce the knowledge gap on the effect of filling amount, the purpose of this paper is an investigation of the thermal behavior of excess liquid. Overfilled sodium heat pipe having about 260% filling ratio was fabricated and tested with the change of boundary and initial condition. Sodium heat pipe showed good isothermal characteristics that the temperature difference between evaporator and condenser reduced as the development of continuum flow until reaching operating limit condition. The characteristics of an overfilled heat pipe appear at power increased after the continuum flow fully developed to the condenser that sudden temperature rise about 100 °C in the overall heat pipe except the end region of the condenser where a continuous temperature about 50 °C drop occurs. Excess liquid moves toward the condenser end and forms the liquid pool and lessening the active condenser length which reduces the maximum heat transfer of heat pipe and induced the operating limitation. The results showed that this phenomenon only occurs at high heat flux conditions as sufficient vapor flow is required to allow excess liquid to propagate to the condenser and determined the operating limitation of overfilled sodium heat pipe that continuous temperature rises as the liquid propagates to the end of the condenser rather than the abrupt rising such as dry out. However, the operating limitations occur sudden dry-out of the evaporator similar to the conventional results of liquid metal heat pipe when the liquid propagation did not occur. Compared to the entertainment limit model, there was a significant difference in the dry-out point of the experimental results with excessive liquid propagation. It was confirmed that the horizontal operation of overfilled heat pipe was in good agreement with the prediction of capillary limit model within 22.6% of the maximum error.

The effectiveness of weed extract with different temperature aquades solvent for controlling antraknosa disease of red chili (Capsicum annum L.)

Red chili is an agricultural commodity with high economic value. National red chili production is still low and often does not meet the needs of the Indonesian people. One of the causes is anthracnose disorder. Red chili anthracnose caused by the fungus Colletotrichum capsici is characterized by symptoms of small black spots that can widen, dry out and shrink and the fruit can fall off. The aim of the study was to determine the effectiveness of extracts of several types of weeds with distilled water at different temperatures against anthracnose disease, growth, and yield of red chili plants. The study was a field experiment using a two-factor Completely Randomized Design (CRD). Factor 1 Types of weeds consist of: bandotan, kirinyuh, teki. Factor 2 Aquades Solvents with Different Temperatures consist of: room temperature, 50°C, 90°C. The variables observed were the intensity of anthracnose disease, plant height, number of healthy fruit, healthy fruit weight, number of sick fruit, phytotoxicity test and phytochemical screening test. The process of spraying botanical extracts is carried out once a week. The results showed that the type of weed extract treatment had a significant effect on the intensity of anthracnose disease and the number of sick fruits and had no significant effect on the number of healthy fruit, healthy fruit weight, and plant height. The treatment of distilled water with different temperatures did not significantly affect all observed variables. The interaction between the type of extract and the temperature of the solvent had a significant effect on the number of sick fruits. Bandotan extract treated with distilled water at room temperature produced the least number of sick fruits, namely 3.4 fruit/plant. The solvent temperature of 50°C produced more phytochemical compounds than the 3 types of weeds extracted. Red chili plants do not show any phytotoxic symptoms.

Drying of cable backfill by vapour diffusion balanced by capillary water suction: a laboratory experiment with altered groundwater levels

The performance of underground infrastructures, such as an electrical transmission cable, is strongly affected by transmission-induced high temperatures, which have an impact on the properties of the cable and the electric load. Therefore, it is essential to determine if a high load will cause a dry out of a sandy thermal backfill close to the cable. This paper aims at describing processes and establishing criteria for when a dry out can occur. Processes that are addressed are e.g., vapour diffusion and capillary water transport. Criteria of interest are e.g., groundwater levels and capillarity of soil. A new pilot laboratory experiment, with varying groundwater levels, was developed to investigate the dry out of the cable sand in close proximity to an operating cable. The experimental results show that a thermal backfill can withstand a dry out, at a high current load in a cable, if there is a capillary contact to a groundwater level 2 m below the backfill material.

Increasing productivity of valuable agarwood in Senggreng Village, Malang Regency

Wisma Gaharu as one of the plantations assisted by the Malang Regency Perhutani Service conducts an agarwood nursery with the species Gyrinops Versteegii. However, the agarwood plants cultivated at Wisma Gaharu are attacked by caterpillars annually, causing damage to the agarwood leaves. Accordingly, the growth of agarwood plants is hampered, and further dry out and die. This causes the owner of Wisma Gaharu to suffer huge losses, especially if the pest attacks the plant which is ready for the inoculation process in the dry season. To overcome this, agarwood farmers must pay high attention and vigilance to fight agarwood caterpillar attacks that occur throughout the year since it is considered the most dangerous pest for plants. The unavailability of production support equipment is one of the problems faced by Wisma Gaharu; there is also a need for work safety training (K3) regarding proper supporting equipment use considering the risks faced by workers in the agriculture sector. The above problems underline the main reasons for supporting equipment procurement and administering work safety training.

Conceptualization of the micro research reactor cooled by heat pipes (MRR-HP), part-II: safety analyses

ABSTRACT The safety of the novel Micro Research Reactor cooled by Heat Pipes (MRR-HP) design is explored. This is achieved by developing a 3D thermal conduction model using STARCCM+ software, besides, coupling it with the 3D neutronics model for reactor dynamics. The MRR-HP has a unique design characteristic, which is the implementation of dual-sets of heat pipes (HPs) in the monolithic-block: Water-HPs for operation, and Potassium-HPs for accident/post-accident scenarios. Water-HPs cool the reactor effectively, allowing for maximum fuel temperature (K). However, water-HPs may suffer from: Loss-of-heat-Sink-Accident(LOSA), which may occur due to blackout, since it requires forced convective cooling in the condenser. Non-Condensable-Gases-Generation-Accident (NCGGA), due to radiolysis. These events cause significant melting in the monolithic-block and fuel rods after 3 and 6 hours, respectively. This paper proves the reliability of potassium-HPs as a passive countermeasure against LOSA and NCGGA, while natural convective cooling in the condenser is applied. Cold-state no-scram Reactivity-Insertion-Accident (RIA) scenarios with an insertion of 2.35$ are investigated, showing that no partial or significant melting occurs, due to the negative reactivity feedback of the MRR-HP. Besides, Potassium-HPs are essential in removing the decay heat, for warm-state RIA, after water-HPs dry out. This paper proves the robustness of the MRR-HP and encourages its utilization for remote operation.

The effectiveness of biofertilizer biofilm formulation in promoting the growth of Pak choi (Brassica rapa L.) plant

One of the climate changes is the El Nino phenomenon, causing the soil to dry out, so it needs to be addressed because it will impact plant growth. Farmers use a lot of inorganic fertilizers (NPK), and in the long term, it can cause soil damage. One alternative treatment is to use organic fertilizers or biological fertilizers. Biofilm biofertilizer is a form of biological fertilizer. This study aims to determine the effect of dosing biofilm biofertilizer on the growth of Pak choi plants so that it can help reduce the use of inorganic fertilizers. This type of research was an experiment in a greenhouse using a completely randomized design (CRD) with six treatments, consisting of A (100% inorganic fertilizer), B (75% inorganic fertilizer and 25% biofilm biofertilizer), C (50% inorganic fertilizer and 50% biofertilizer biofilm), D (25% inorganic fertilizer and 75% biofertilizer biofilm), E (100% biofertilizer biofilm), and F (no inorganic fertilizer and no biofertilizer biofilm). Each treatment was repeated four times. Parameters used in this study included plant height, number of leaves, dry weight and wet weight, and leaf diameter. Data analysis used the ANOVA test with a 95% confidence level, followed by Duncan's Multiple Range Test (DMRT). The results showed that the combination of 25% biofertilizer biofilm treatment with 75% inorganic fertilizer gave the best results compared to the control and other treatments. The treatment of 25% Biofilm biofertilizer with 75% inorganic fertilizer was able to increase plant height by 21.175 cm or 74.24% higher than control, number of leaves by 17.25 strands or 65.62% higher than control, leaf width by 7.125 cm or 61.80% higher than control, wet weight by 28.083 g or 97.29% higher than control, and dry weight by 1.869 g or 95.88% higher than control so that this treatment can be an alternative to reduce the use of inorganic fertilizer.

Soil water and solute transport in an Andosol apple orchard including the dormancy period in a snowy cold region

Early spring corresponds to the snowmelt season in apple orchards of the northern hemisphere. This has a significant effect on the initial growth of shoots and flower buds of apple trees. Understanding the soil environment of the orchard during the non-growth period as monitored by farmers is important for managing year-round apple production. However, the details of mass transport, such as that of soil water and solute, during the non-growing season in the Andosols remain unclear. This study conducted soil environment monitoring in an Andosol apple orchard in Aomori Prefecture, Japan, during the non-growing season in winter to examine the year-round changes in the soil environment, using a field monitoring system that is necessary for understanding the soil environment. Volumetric water content, soil bulk electrical conductivity, and soil temperature were measured, and the cumulative changes in total soil moisture (ΣΔTSM) were calculated from the monitored volumetric water content. Results showed that although ΣΔTSM tended to increase (i.e., dry out) annually with periodicity, the variation was small compared to that of apple orchards with gravelly brown forest soil. These results could significantly influence fertilization management of apple orchard soil during the summer drought season and early spring when the roots of apple trees begin taking up nutrients. In particular, it was revealed that if sufficient nutrients remain in the soil pore water in early spring, the negative impact of excessive fertilization on the surrounding environment can be reduced. Therefore, this study constitutes an innovative step in the implementation of field monitoring system to understand the details of mass transport in the Andosol apple orchard soil.

Enhancement of flow boiling heat transfer by laser-induced periodic surface structures using femtosecond laser

This study proposes a new surface processing method using a femtosecond laser to enhance the flow boiling heat transfer in a single mini/micro-channel duct. The suggested method is suitable for mini/micro-channel surface processing because the femtosecond laser with a short pulse duration (∼220 femtoseconds) simplifies the fabrication procedure and minimizes the thermal damage of surfaces during laser processing. Three types of laser-induced surfaces different in the nano-surface structure were fabricated. Three surfaces include laser-induced periodic surface structure (LIPSS), micro-groove covered clustered cavity by low fluence (MGCC-LF), and micro-groove covered clustered cavity by high fluence (MGCC-HF). Flow boiling heat transfer of each surface was experimentally investigated through a comparison with that of the plain copper surface in single-channel experiments. Experimental results demonstrated that LIPSS enhanced the boiling heat transfer by increasing the bubble nucleation sites with a self-organized nanosized ripple structure. Consequently, the MGCC-HF surface with nanosized clustered cavities and hydrophilic characteristics has the most prominent flow boiling heat transfer and critical heat flux enhancement. This enhancement is due to a synergy between increased nucleation sites and the wicking effects, promoting liquid rewetting and hindering local dry out. The present study confirmed that the flow boiling performance of the metal surface could be significantly improved through a relatively easy and fast process using a femtosecond laser.