Rise Height Research Articles

Плантационное выращивание Pinus sibirica Du Tour в среднетаежной зоне Республики Коми

In order to create a valuable gene pool of cedar pines in the conditions of the Komi Republic, rootstock crops of Siberian pine (Pinus sibirica Du Tour) were planted on the territory of laboratory training center of the Syktyvkar Forest Institute. The plants were collected from different areas of the Komi Republic and the Arkhangelsk region for adjustment to the local, northwestern climate. The paper presents the results of the variational analysis of morphological parameters and growth dynamics in P. sibirica cultures. Height, trunk diameter, and crown diameter were chosen as the morphometric criteria. The variability of the studied traits ranged from 18.8 to 93.1 %. The average height of the plants was 72.2±3.9 cm, the average trunk diameter was 2.0±0.1 cm. The most changeable characteristic was the diameter of the crown of the plants, which ranged between 11 and 148 cm with Сv of 30.6–93.1 %. The plants of Yarensk origin were the most developed according to the examined morphometric criteria. The average growth of P. sibirica plants in height within the age group of 9–11 years over three years was 13.5±0.9 cm. The lowest growth rate was registered in plants of the Sysola group (1 cm), whereas plants of Yarensk origin had the highest growth rate (38 cm). Throughout the research period, plants of all groups had a consistent rise in overall height. However, this trait variability was reduced only in the group of plants of Yarensk origin. The maximum variability in all three traits was observed in plants of Syktyvkar origin with Сv of 39.7–93.1 %. In general, high variability in the development of Siberian pines over three years across all experimental groups was detected. The investigation results can be applied for further research on the development and inheritance of economically valuable traits and decorative characteristics of P. sibirica in the conditions of the middle taiga subzone of the Komi Repub lic. For citation: Parshina E.I., Dymova O.V., Titov E.V. Plantation Cultivation of Pinus sibirica Du Tour in the Middle Taiga Subzone of the Komi Republic. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 195–204. (In Russ.). https://doi.org/10.37482/0536-1036-2023-3-195-204

A novel approach for mobile kentledge loading in plate load tests on coal mine-over burden dumps

Acute space crunch in the mining places lead to use of overburden dumps for rehabilitation and construction of new structures. Evaluation of stability and bearing capacity is of prime concern in utilization of these overburden dumps for further construction activities. In this study, the use of novel mobile plate load test for determining the bearing capacity of mine over burden dumps is discussed in detail. Conducting conventional plate load tests with traditional kentledge load is a costly, time-consuming, and necessitate huge workmanship. To overcome these setbacks, in this study the mine-excavator is modified to mobile kentledge loading arrangement. Using this novel approach, the time for testing is reduced by about 90% and the cost of work is reduced by about 200% with safe working environment. Further, the bearing capacity results are compared with the corresponding values obtained through standard Terzaghis estimation methods. Results obtained through Terzaghis method are found to be over conservative compared to the in-situ Plate load test evaluations. Thus, through this study it is recommended to perform enough plate load tests to conclude the actual bearing capacity and settlement of mine over-burden dumps that are non-homogenous and filled in an unscientific manner. Further, the safe ultimate bearing capacities were used for understanding the safety against capacity enhancement for probable rise in height of mine over burden dumps.

Heel riser height and slope gradient influence the physiology of ski mountaineering-A laboratory study.

In ski mountaineering it is the goal to reach the top of a mountain by sheer muscle force. The specific equipment (flexible boot, only toe fixated binding, and a skin on the ski to prevent from slipping backwards) enables the skier to move up the hill ergonomically, where the heel part of the binding offers a special adaptation possibility. The so-called riser height supports the heel standing height and can be adjusted to individually preferred settings. General recommendations suggest using lower heel support in flat ascents and higher heel support in steep ascents to maintain upright posture and lower the strain. Still, it remains unclear whether the application of riser height affects the physiological response during ski mountaineering. This study was designed to investigate the effects of riser height on physiological response during indoor ski mountaineering. Nineteen participants took part in the study and walked on a treadmill with ski mountaineering equipment. The three available riser heights (low, medium, and high) were applied randomized at 8%, 16%, and 24% gradient. Results show that global physiological measurements like heart rate (p = 0.34), oxygen uptake (p = 0.26) or blood lactate (p = 0.38) values were not affected by changes in riser height. But local measurements of muscle oxygen saturation were affected by the riser height. Additionally comfort and rating of perceived exertion were also prone to changes in riser height. These results suggest differences on local measurements and perceived parameters, while global physiological measurements did not change. The results are in line with the existing recommendations but need to be confirmed in an outdoor setting as well.

Ionosonde and GPS total electron content observations during the 26 December 2019 annular solar eclipse over Indonesia

Abstract. We report the investigation of the ionospheric response to the passage of an annular solar eclipse over Southeast Asia on 26 December 2019 using multiple sets of observations. Two ionosondes (one at Kototabang and another at Pontianak) were used to measure dynamical changes in the ionospheric layer during the event. A network of ground-based GPS receiver stations in Indonesia was used to derive the distribution of total electron content (TEC) over the region. In addition, extreme ultraviolet (EUV) images of the Sun from the Atmospheric Imaging Assembly (AIA) instrument on board the Solar Dynamics Observatory (SDO) satellite were also analyzed to determine possible impacts of solar-active regions on the changes that occurred in the ionosphere during the eclipse. We found −1.62 and −1.90 MHz reductions (24.0 % and 27.5 % relative reduction) in foF2 during the solar eclipse over Kototabang and Pontianak, respectively. The respective TEC reductions over Kototabang and Pontianak during the eclipse were −4.34 and −5.45 TECU (24.9 % and 27.9 % relative reduction). Data from both ionosondes indicate a consistent 34–36 min delay between maximum eclipse and minimum foF2. The corresponding time delays for eclipse-related TEC reduction at these two locations were 40 and 16 min, respectively. The ionospheric F layer was found to descend with a speed of 9–19 m s−1 during the first half of the eclipse period. We also found an apparent rise in the ionospheric F-layer height near the end of the solar eclipse period, equivalent to a vertical drift velocity of 44–47 m s−1. The GPS TEC data mapping along a set of cross-sectional cuts indicates that the greatest TEC reduction actually occurred to the north of the solar-eclipse path, opposite of the direction from which the lunar shadow fell. As the central path of the solar eclipse was located just to the north of the southern equatorial ionization anomaly (EIA) crest, it is suspected that such a peculiar TEC reduction pattern was caused by plasma flow associated with the equatorial fountain effect. Net perturbations of TEC were also computed and analyzed, which revealed the presence of some wavelike fluctuations associated with the solar-eclipse event. Some of the observed TEC perturbation patterns that propagated with a velocity matching the lunar shadow may be explained in terms of nonuniform EUV illumination that arose as various active regions on the Sun went obstructed and unobstructed during the eclipse. The remaining wavelike features are likely to be traveling ionospheric disturbances (TIDs) generated by the passage of the solar eclipse on top of other diurnal factors.

Thermals from finite sources in stable and unstable environments

The rise of thermals in the atmosphere has attracted a lot of attention since the early work of Morton et al. (Proc. R. Soc. Lond. A, vol. 234, 1956, pp. 1–23), who proposed that entrainment into a thermal was proportional to the surface area of the thermal and to the mean vertical velocity of the thermal. This paper presents new analytical solutions for the heights of rise of buoyant thermals in both stably and unstably stratified environments, for both negatively and positively buoyant sources, and where the sources have different size and strength (momentum) characteristics. The limiting cases of these analytical solutions are consistent with previous work. These analytical solutions do not appear elsewhere, and provide a compact set of equations that are easy to apply to a wide range of circumstances. The solutions are dependent upon the entrainment hypothesis, which is of course only an approximation, but the simplicity of the analytical solutions allows easy calculation and additional insights. These include the fact that while heights of rise are strongly dependent on both source strength and size for flows in stable environments, the dilution at the top of rise is independent of the source momentum. Further, in a stable environment, there is a conserved quantity that has dimensions proportional to vertical momentum. For negatively buoyant flows in an unstably stratified environment, thermals having low initial momentum will reach a maximum height, while thermals with high initial momentum will entrain sufficient buoyant environmental fluid that they will eventually become positively buoyant and continue to rise indefinitely.

Late Holocene Cliff Retreat in Del Mar, CA, Revealed From Shore Platform 10Be Concentrations and Numerical Modeling

AbstractRocky coast cliff retreat presents a hazard to coastal communities and infrastructure that is potentially amplified under rising sea level conditions, among other factors. Unfortunately, constraints on retreat rates are typically limited to those derived from imagery and maps spanning the last ∼100 years. Here, we use a newly developed coupled model of shore platform profile evolution and cosmogenic radionuclide production that considers the influence of relative sea level (RSL) rise, weathering, material resistance, and wave height decay to model cliff retreat over millennial timescales and its potential drivers in Del Mar, California. We demonstrate the ability to use topographic and bathymetric measurements from a narrow shore platform along with a limited data set of nine cosmogenic 10Be concentrations extending ∼125 m from the cliff base to obtain modeled cliff retreat rates that steadily range from 5.0 to 12.5 cm yr−1 over the last two millennia until 100 years before present. These rates are consistent with modern retreat rates of about 2–19 cm yr−1 here. RSL rise in Southern California remained relatively constant during the late Holocene, potentially explaining the relatively stable modeled cliff retreat rate over this time. We also explore the relative influence of weathering, material resistance, and wave erosion efficacy and find that both weathering and wave‐driven erosion are necessary to replicate the measured data at this location, with the latter exerting a stronger control on model acceptance, suggesting that waves may provide a possible mechanism by which RSL rise may influence coastal cliff erosion in southern California.

Molecular dynamics simulation study on interfacial behaviors of betaines and extended surfactants

The mixed system between different surfactants has characteristic and synergy to reduce the oil/water interfacial tension (IFT). As the reservoir conditions become more and more severe, it is necessary to explore new surfactants suitable for complex geological environments. In this work, we designed the mixed systems between betaine and extended surfactants, and studied the interfacial properties at the decane/water interface by molecular dynamics (MD) simulations and interfacial tension measurements. The effects of betaine structure and oxypropylene (PO) chain length of extended surfactant on the interfacial behaviors were analyzed in detail from the density profile, tilt angle, average rising height of PO unit and radial distribution function. The results showed that the polar part of betaine extended into the water phase and the hydrophobic chain was more upright in the mixed system due to the electrostatic interaction. For the mixed system, the rise height change of the PO unit indicated that the interfacial behavior of short PO chain was controlled by betaine structure, while that of long PO chain was independent of betaine structure because of the poor deformation ability of it. IFT experiments showed that xylyl substituted alkyl sulfobetaine (XSB) mixing with the short PO chain extended surfactant system had a significant synergistic effect to produce ultra-low IFT but had a negative effect with the long PO chain extended surfactant. This work demonstrated that the steric hindrance of betaine and the PO chain length of extended surfactant synergistically affected the interfacial arrangement and IFT of surfactants, which was of significance for improving and designing more effective surfactant flooding systems to enhance oil recovery.

Using Oil and Lithium Carbonate to Predict New Energy Vehicle Sales in China by Linear Regression Analysis

Recently, a heated discussion has been centered on new energy vehicles, with derivative topics such as the violent rise and new height of oil price and also lithium price, the technical development, and sales volume of Lithium batteries, the rising price of new energy vehicles, and so on. As the new energy vehicle has been expected as one of the most important measures to protect the environment and save traditional fuel energy, it is crucial to accurately understand and explain how the price and import volume of oil and Lithium carbonate impact the sales of new energy vehicle in China and the relationships between each factor, based on linear regression analysis. In this paper, the output of Lithium batteries represents the sales of new energy vehicles in China. The result reveals that the price and import volume of oil and Lithium carbonate all have significant linear relationships with the output of Lithium batteries in China, while the most influential factor is Lithium carbonate price and the weakest factor is Oil import volume. Moreover, these factors interact with each other obviously when they affect the output of Lithium batteries together. The above results of the research provide a theoretical reference for relevant policies to slightly adjust the price of oil and lithium, for companies to modify sales strategies and for consumers to take action to accommodate the general trend of prosperous development of the new energy vehicle industry.

Calculation of the Technical Characteristics of the Irrigation Plant Operating Due to the Kinetic Energy of the River Flow Based on Mathematical Modeling

The article deals with the issue of irrigating pastures with the help of an irrigation plant that operates due to the kinetic energy of the river flow. The issue of pasture irrigation in conditions without electricity has been studied. Calculations were carried out to determine the technical characteristics of the irrigation system. The power, pressure at the height of the water, flow rate and productivity of the irrigation plant have been established. The power of the river flow, natural pressures for the installation of the pump are determined. The dependences of the efficiency factor on the supply of the pump operating due to the kinetic energy of the river flow in different values of the rise of water to a height are established. The dependences of the height of water rise on the pump delivery are investigated and the required delivery value for the required height is established.

Rough capillary rise

Capillary rise within rough structures is a wetting phenomenon that is fundamental to survival in biological organisms, deterioration of our built environment, and performance of numerous innovations, from 3D microfluidics to carbon capture. Here, to accurately predict rough capillary rise, we must couple two wetting phenomena: capillary rise and hemiwicking. Experiments, simulations, and theory demonstrate how this coupling challenges our conventional understanding and intuitions of wetting and roughness. Firstly, the critical contact angle for hemiwicking becomes separation-dependent so that hemiwicking can vanish for even highly wetting liquids. Secondly, the rise heights for perfectly wetting liquids can differ between smooth and rough systems, even with the same 0∘ contact angle. Finally, the raised liquid volumes are substantially increased in rough compared to smooth systems. To explain and predict all rise heights and volumes with quantitative accuracy, we present the Dual-Rise model that is valid for general roughness, liquids, and surface wettabilities.

Capillary Rise in Layered Soils

Capillary rise tests were conducted on soil columns containing of three layers of sandy soils with coarser over finer over coarser sandy soil to investigate the effect of the relatively finer soil interlayer. The capillary rise height, rate, and water distribution were observed in laboratory tests of four layered soil columns, with two homogeneous (without the interlayer) soil columns serving as the controls. The final maximum height of the capillary rise in the soil column with the interlayer was larger than that of the column without the interlayer when the interlayer was laid around the water entry value of the underlying soil. The water content was not continuous in the entire soil profile with the interlayer, and a small matric suction gap was observed in the relatively fine soil between the soil column with and without the interlayer.

Laser Melt Infiltration of UHMWPE into the Binary Coatings of Strontium Apatite and Colloidal Silica

Medical-grade ultrahigh molecular weight polyethylene (UHMWPE) is the material of choice for sliding surfaces in various articular joint implants owing to its excellent biocompatibility and superior physical properties, such as an exceptionally low coefficient of friction and excellent durability. However, the bioinert nature of UHMWPE limits its extended use in rapidly advancing medical fronts. In this study, bioactive surface modifications of UHMWPE were addressed using a newly developed laser-melt infiltration technique. UHMWPE was coated with binary mixtures of strontium apatite and colloidal silica particles and irradiated using a 30 W CO2 laser to reach the maximum temperature of 150 ± 5 °C. UHMWPE melts infiltrated the porous matrices of the coatings by capillary force and formed surface-selective composite materials between them. Capillary rise heights were evaluated by observing the uplift of the substrate after the selective dissolution of the coating substances and were found to be much higher than the estimated values based on the Lucas–Washburn equation. This finding suggests that the melt viscosity of UHMWPE confined within the nanopores might be significantly lower than that measured at macroscopic scales. Both strontium and silicate ions are known osteo-inductive factors, and their concentrations eluted from the binary coatings were substantially higher than those found in the single coatings.

Two Decades of Monitoring Hydrothermal Plumes at the Brothers Submarine Volcano, Kermadec Arc, New Zealand

Abstract Brothers volcano is arguably the most well-studied submarine arc volcano on Earth. Between 1996, when massive sulfides were first recovered by dredging, and 2018, when International Ocean Discovery Program (IODP) Expedition 376 recovered cores from as deep as 453 m below the sea floor at two chemically distinct hydrothermal upflow zones, over 60 conductivity-temperature-depth (CTD) vertical casts and tow-yo operations mapped hydrothermal plumes over and around the edifice by employing hydrothermal tracer-specific sensors. These surveys started in 1999 and were completed during nine separate expeditions at one- to three-year intervals, except for a six-year gap between 2011 and 2017. Hydrothermal plume distributions over this two-decade period show variability in the intensity and vertical rise height of plumes from the four main vent fields (Upper Cone, Lower Cone, NW Caldera, and Upper Caldera, with the latter not discovered until 2017). Upper Cone plumes were more intense than all other sites in 1999, 2002, 2007, and 2009, then significantly diminished from 2011 to 2018. The Lower Cone plume was the most intense in 2004, then the NW Caldera site became the dominant source of hydrothermal particles from 2011 to 2018. Despite the gap of six years between 2011 and 2017, hydrothermal output appears to have increased within the caldera sometime after the 2009 survey while simultaneously decreasing in intensity at the cone sites. This supports other evidence of linkages between the cone and caldera sites in the deep hydrothermal circulation system, and may be related to the predicted deepening of hydrothermal circulation, infiltration of seawater to facilitate “mining” of magmatic brines, and modulation of subseafloor mineralization processes associated with a modeled, pulsed injection of magmatic gasses. The surveys also revealed ways in which the highly variable regional hydrographic environment impacts the flux of hydrothermal products to the surrounding ocean. Plumes from sources located above the caldera rim disperse hydrothermal components without hindrance, but particles and heat from sources within the caldera become trapped and are dispersed episodically by caldera-flushing events. While on site for 18 days in 2018, repeat CTD casts into the deepest part of the caldera, which was isolated from the surrounding ocean, showed a progressive increase in temperature, representing a net heat flux of 79 MW from conductive and advective sources deeper than 1,570 m.

Hyperspectral imaging-based early damage degree representation of apple: a method of correlation coefficient

Early damage detection of fruit is a challenge in the postharvest treatment of agricultural products, especially the lack of early damage degree representation. In this study, the damage distribution of apples was experimentally investigated through impact tests based on hyperspectral imaging technology. A parameter–correlation coefficient Cfg is proposed to characterize the damage distribution of fruit. The damage index DIx is further defined to measure the damage degree. This method uses the distribution of the correlation coefficient field to evaluate the damage and determines the relationship between the reflectance and the drop height. The index gradually increases with the rise in drop height. The damage index DI0.6 was 0.2106, 0.2925, and 0.3585 at the drop heights of 0.3 m, 0.6 m, and 0.9 m, respectively. The results of the damage distribution were also interpreted using the finite element method. This non-destructive method can be used to reflect the damage distribution of apples under impact accurately, which provides a solid basis for assessing early damage in postharvest fruit.

Measurement of Total Air Entrainment, Disentrainment and Net Entrainment Flow Rates Utilizing Novel Downcomer Incorporating Al-Anzi’s Disentrainment Ring (ADR) in a Confined Plunging Jet Reactor

Plunging liquid jet reactor (PLJR) has gained popularity as a feasible and efficient aerator and mixer. However, the measurement of air disentrainment rate (Qads), which affects aeration performance, has been overlooked by many researchers. In this work, a newly invented Al-Anzi disentrainment ring (ADR) device was incorporated in CPLJR to experimentally measure Qads and its effect on the net air entrainment rate. Furthermore, the effect of new variables (lADR and ds) and old variables (Lj and VL) on Qanet were also investigated. Results showed that shorter ds and lADR produced higher Qanet for the same ADR device. A new net entrainment jet velocity at the impingement point (VLnet) was measured at about 651 cm/s, above which bubbles left the base of downcomer as Qanet. Qanet increased linearly with VL; however, Qads increased until it reached maximum value, and then decreased. Bubble penetration depth and liquid rise height increased for all VL until they reached maximum, and then leveled off for the same lADR. A significant increase in Qanet values was achieved with this downcomer in comparison with the conventional one. The increase in Qanet was measured to be approximately 2.5–15 times of that measured by the standalone downcomer.

Research on the submarine floating movement in waves involving the water holes

When a submarine with a large volume superstructure floats up, the water on the back of the superstructure is large. In order to ensure the safety of submarine floating, it is necessary to study the stability and attitude change of submarine floating. In the present study, STAR-CCM + software is used to construct a numerical wave pool based on the numerical wave making theory. Based on the overset grid, the calculation method for internal and external domains interaction is adopted, and the uncertainty of the numerical calculations is analyzed using the model floating test results. What's more, the numerical results of the hull longitudinal and vertical velocities, and heel and pitch angles are close to the test results, except for the peak values. Compared to the test results, the average error of the amplitude of the numerical results was within 10%.It can thus be concluded that the numerical simulations were credible, which confirmed that the proposed numerical method can be applied to simulating the emergency ascent of a submarine with flow holes. Finally, a numerical prediction method for submarine floating movement in waves considering the superstructure water hole is proposed. The characteristics of the submarine buoyancy and emergence in waves are explored for various wave directions, wave heights and wavelengths. The results indicate that beam waves have a greater impact on the lateral orientation of the submarine, while the head waves are more effective on the longitudinal direction. Furthermore, the heel angle of the submarine is higher in beam and oblique waves compared to that in head waves. The longitudinal displacement shows a descending trend as the wave height increases. As the submarine exits the water, the hull posture is affected by waves, and the heel and pitch angles tend to increase by the rise of wave height. Based on a given wavelength range of 1∼3L, the higher wavelengths increases the longitudinal and lateral displacements of the hull, and reduces its heel and yaw angles. For shorter wavelengths, the hull responds faster to variations induced by the wave disturbances. It can be concluded that submarines should avoid surfacing in shorter wavelengths as well as in beam waves. The proposed numerical methods and conclusions of the present study can be considered as a reference in the scope of submarine floating movement.

Vertical and lateral random vibration of high-temperature superconductor maglev under high-speed operation conditions

High-temperature superconductor (HTS) maglev systems shows significant potential to be applied to high-speed rail transportation based on its passive stable levitation owing to the coupling between the HTS bulks and permanent magnetic guideway (PMG). As one of the key factors to guarantee the safe and stable operation of HTS maglev, the dynamic characteristics of the HTS bulks reflecting the operational performance of the HTS maglev system under high-speed running conditions should be focused on. Therefore, this paper, based on H-formulation, established a finite element model of an HTS-PMG system, and assessed its feasibility by experiments. Moreover, the random free vibration of the HTS bulk caused by guideway random irregularity at high speed is also studied by this validated model. The random vibration characteristics and temperature variation of the HTS bulk at three high speeds (600 km h−1, 800 km h−1, and 1000 km h−1) under vertical vibration, lateral vibration, and vertical-lateral coupling vibration, respectively, are compared. The results show that at high speed, vertical vibration can only cause the fluctuation of levitation height, while lateral vibration and vertical-lateral coupled vibration will affect both lateral offset and levitation height. Compared with the mere vertical or lateral vibration mode, the levitation height attenuation and temperature rise of the coupling vibration mode is greater due to more energy loss caused by magnetic flux motion, but it can aid in the suppression of the vibration in the vertical and lateral directions. The increase of velocity intensifies the vibration strength of the HTS bulk and increases the fluctuation of the levitation height, lateral offset, and temperature rise. However, vibrations at a certain high speed causes a limited temperature rise and thus a limited influence on the bulk performance, and the HTS bulk is still in the safe operating range at a maximum speed of 1000 km h−1. These conclusions are anticipated to provide some references for future high-speed applications of the HTS maglev system.

Hygro-thermal characterization of the hemp concrete modified with the gum Arabic admixture

This paper presents the investigation of the hygro-thermal properties of hemp concrete modified with gum Arabic (GA) admixture. The effects of modifying agents on the composite: density, total porosity, thermal conductivity, vapor permeability, sorption/desorption curves, and capillary uptake were studied. The main findings were the following. A slight tendency to increase density (i.e., from 444.2 to 450.2 kg/m3) and decrease porosity (i.e., from 79.5 to 79.0 %) with an increase in the admixture content was observed. The exception was the composite with the lowest amount of GA admixture (i.e., 1 % wt.), which had a lower density (i.e., 440.5 kg/m3) and higher porosity (i.e., 79.8 %) than the reference composite with no admixture. Thermal conductivity for dry composites rose by approximately 10 % for higher amounts of GA admixture (i.e., to 0.1179 and 0.1181 W/m/K for 3 and 5 % wt. of GA, respectively), while for lower ones (i.e., 1 % wt.), it was comparable to reference hempcrete (0.1067 W/m/K for reference vs 0.1053 W/m/K for 1 % wt. of GA). An increase in the moisture content of composites increased thermal conductivity but also reduced its variation for different GA contents. All composites had similar water vapor permeabilities on the levels of 3∙10-11 and 5∙10-11 kg/m/s/Pa for dry and wet caps, respectively, and no simple relationship was found between water vapor permeability and GA content. The addition of GA caused the shift of sorption/desorption curves in the direction of higher moisture contents, increasing amounts of absorbed water more than two times in higher relative humidities. The presence of higher amounts of GA (i.e., 3 and 5 % wt.) reduced the height of the water rise by capillaries, i.e., by 10.3 and 21.0 %, respectively, after 8 days of testing, and slowed down the progress of capillary uptake. However, the composite with 1 % wt. GA absorbed 16.7 % more water than the reference sample.

Plasma Treatment as a Sustainable Method for Enhancing the Wettability of Jute Fabrics

In this paper, raw jute fabric was subjected to atmospheric pressure dielectric barrier discharge (at 150 or 300 Hz) to enhance its wettability, i.e., capillarity and wetting time. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Field Emission Scanning Electron Microscopy (FE-SEM) were used to assess the changes in the fabrics’ surface chemistry and morphology induced by plasma treatments. The obtained results revealed that both plasma treatments enhanced the wettability of jute fabrics, which could be ascribed to the changes in the fibers’ surface chemistry (the removal of non-cellulosic components, exposure of the cellulose molecules, and oxidation) and morphology (increased roughness due to etching of the surface layers and partial fibrillation). Capillary rise heights increased by approximately 1.8 and 1.9 times, and wetting times were 35 and 34 times shorter 24 h after the plasma treatment at 150 and 300 Hz, respectively. Special attention was given to the aging effect of plasma treatment indicated no significant changes in the fabrics’ capillarity and wetting time after 28 and 7 days, respectively, proving the durability of the effects of plasma treatment. Plasma-treated raw jute fabrics could be used as water-binding geo-prebiotic polysaccharide supports to provide the necessary water for the initial growth of cyanobacterial biocrusts. The lack of moisture is the main constraint in biocrust development after cyanobacterial inoculation. The combination of such water-supportive fabrics and cyanobacterial strains could be used for the rehabilitation of various degraded lands, sediments, and substrates, as well as for air and water pollution control.

Investigation on Convection Heat Transfer Augment in Spirally Corrugated Pipe

A numerical simulation on the heat transport augmentation and flow drag behavior of spirally corrugated pipes was performed. The simulation was conducted on the basis of the experimental results documented in the published literature. The influence of the thread height and pitch on the hydraulic–thermal performance as well as the mechanism of the convection heat transport development inside the spirally corrugated pipe were explored. It was discovered that the convection heat transport performance elevates in the Reynolds number region of 4000~13,000 as the thread height rises or the Reynolds number enlarges, but it declines when the thread pitch extends. The convection heat transport performance marked by the Nusselt number of the spirally corrugated pipe could reach 2.77 times that of the plain pipe, while the flow resistance coefficients of spirally corrugated pipes are 89~324% above that of the plain pipe. It enlarges with the rise in thread height but declines with the extension of the thread pitch. It also reduces when the Reynolds number enlarges. The factors of overall heat transmission performance for all the spirally corrugated pipes are above 1.00, and they increase in the Reynolds number region of 4000~7000 and then decrease in the Reynolds number region of 7000 to 13,000. The secondary flow at the cross-sections and the vortex between two adjacent corrugated grooves are the basic causes of the promotion of convection heat transport inside the spirally corrugated pipes. The secondary flow near the pipe wall both disrupts the border layer and boosts the radial interfusion of the fluid. In addition, the existence of vortexes makes the secondary flow act on the convection heat transmission continuously and positively in the region close to the pipe wall.