Wick Length Research Articles

Características productivas y tecnológicas de la fibra de alpacas Suri del Centro Experimental Chuquibambilla, Puno

This study seeks to determine the productive and technological characteristics of Suri alpaca fiber at the Chuquibambilla Experimental Center. Samples were taken from 110 alpacas during the 2022 shearing campaign, analyzed in the laboratory of INIA’s Quimsachata Experimental Station. The results showed a dirty fleece weight of 2118.64 ± 387.82 g, similar until four years and with a significant decrease from five years (P ≤ 0.05). The average wick length was 88.00 ± 16.13 mm, also similar up to four years. The mean fiber diameter (DMF) was 20.61 ± 0.33 μm, increasing with age (P ≤ 0.05), and the standard deviation of the DMF (DSDMF) was 4.74 ± 0.08 μm, with an age-related increase (P ≤ 0.05). The coefficient of variation of the DMF was 23.06%, with no significant differences between ages (P > 0.05). The comfort factor (HR) was 94.27%, decreasing with age (P ≤ 0.05). Fineness at yarn (FH) averaged 20.46 ± 0.37 μm, increasing with age (P ≤ 0.05), and the curvature index was 15.24 ± 0.37 °/mm, with a significant decrease (P ≤ 0.05). It is concluded that age influences the technological characteristics of the fiber, with positive and negative correlations of high magnitude between the variables analyzed.

Solute imbibition in paper strip: Pore-scale insights into the concentration-dependent permeability

Capillary wicking in a thicker gel blot microfluidics paper has been investigated through a combination of an analytical framework, experiments, and numerical simulations. The primary objectives of this work are to investigate the concentration-dependent wicking process inside thicker microfluidic paper and to estimate the concentration-dependent permeability using both theoretical models and experimental data. An additional goal is to estimate the parameters for saturation-dependent flow modeling in thicker microfluidic paper. To comprehend the wicking phenomenon on thicker gel blot paper, a series of experiments employing aqueous food dye solutions at varying concentrations has been conducted. In order to calculate the temporal wicking length analytically, the Brinkman-extended Darcy equation is implemented. By modifying the permeability expression for a simple rectangular unidirectional fiber cell and pure liquid, the expression of effective permeability for the analytical framework has also been introduced. The concentrations of the food dye solutions appear to have a substantial influence on the wicking phenomenon. Effective permeability and wicking length have been found to follow a decreasing pattern at lower concentrations while both increase at higher values. Intriguingly, employing a microfluidics paper with a relatively greater thickness facilitates the visualization of the fluid front. This phenomenon is identified by the formation of an acute angle at intermediate time instants, while the fluid front angle assumes an angle nearly ∼90° during smaller and higher time instants. In order to evaluate the saturation-dependent capillary pressure and permeability, the empirical correlation of concentration-dependent Brooks and Corey parameters is additionally determined experimentally. These parameters are subsequently employed in numerical simulations to illustrate the saturation-dependent flow field using Richards’ equation. Furthermore, numerical simulations based on these estimated model parameters have been conducted, and it turns out that the saturation field has an excellent agreement with the experimental results. The results of the current study can be used to design low-cost paper-based diagnostic devices for usage in healthcare and environmental applications.

Study on Comfort Characteristics of Moisture Management Finished Microdenier Polyester Knitted Fabrics

The influence of stitch length and knit structure on comfort characteristics of moisture management finish microdenier polyester knitted fabrics was determined to identify the suitable stitch length and knit structure. In order to study this effect, microdenier polyester filament yarn of 150 denier containing 108 filaments was taken. The yarn was converted to three knit structures such as single jersey, single airtex, and honeycomb, each containing three different stitch lengths of 2.6, 2.9, and 3.2 mm. The effect of stitch length and knit structure on comfort characteristics of moisture management finish knitted fabrics was significant. It was observed that single jersey fabrics showed quicker sinking times for the wetting test. In the wicking test, the wicking length increased continuously with stitch length for treated fabrics. In transverse wicking test for one drop of water and to reach saturation point, single jersey fabric shows a larger water spreading area. The time taken to reach saturation point is also shorter. In the moisture vapor transfer test for reduction in height and weight of water, single airtex fabrics show higher values. In the air permeability test, the single jersey structure exhibited higher air permeability values. It was observed that the single jersey structure with 2.9-mm stitch length had a superior performance with respect to comfort characteristics.

Spreading of water microdroplets simulating human sweating in polyester yarns and fabrics

Thermo-physiological comfort of human body is highly influenced by the moisture transmission behaviour of the fabric. For active sportswear, intimate apparels and inner layer of extreme cold weather clothing, moisture transport is very crucial. The liquid moisture transport of fabrics is analysed using standardised test methods like vertical wicking, absorbency test and moisture management through moisture management tester. These test methods use large reservoir of liquid in contrast to human sweating behaviour. The human skin generates sweats in the form of microdroplets through sweating glands. Hence, the standard test procedures employed to assess the fabric’s liquid moisture transport fail to capture preciously the sweat transport from human skin to the fabrics. Hence, in this work, the spreading behaviour of water microdroplets simulating human sweat through yarns which are the building block of fabrics and knitted fabrics that are widely used as sportswear or inner layer of extreme cold weather clothing are investigated. The purpose of this study is to understand how the microfluid move along the capillary channels in yarns (in the forms of network of yarns crossing over each other and fabric) by keeping yarn count and twist same for all yarns. A single micro drop representing accumulated sweat droplets and multiple drops showing continuous sweating through sweat glands were allowed to wick through the yarns made up of coarser and finer fibres to understand the role of fibre diameter on wicking kinetics. Results from the conventional wicking test were compared with microfluidic wicking. It is found that the initial wicking speed in coarser-fibres yarn is faster in comparison to finer-fibres yarn, but the final wicking height is longer in finer fibre yarn. Overall liquid spreading length found to be similar for both the yarns. Yarn to yarn liquid transfer at crossover junctions is faster with finer-fibre yarn compared to coarser-fibre yarn. Same trends are found in fabrics constructed with these yarns. The effect of yarn tortuosity on liquid spreading behaviour has also been studied. As the yarn path becomes torturous (straight yarn to fabric form) wicking length also decreases.

A highly efficient and sustainable heat sink via liquid film boiling in hybrid mesh with active liquid supply

Two-phase heat transfer holds great potential to achieve efficient thermal management for high-power applications. However, achieving high thermal performance and sustainability simultaneously could be mutually exclusive. Here, we develop a rational design of a heat sink via liquid film boiling in hybrid mesh with active liquid supply. The heat sink exhibits a high critical heat flux of over 600 W/cm2 and an average heat transfer coefficient of 38 W/cm2K at a flow rate of only 0.4 ml/s on a heating surface of 1 cm2 with water under atmospheric conditions. The proposed architecture that comprises a superhydrophilic porous layer maintaining efficient liquid film boiling via a 3-D manifold decreasing wicking length enables huge heat dissipation with small pumping power and water consumption. The visualizations and the results of theoretical modeling demonstrate that the critical heat flux of the liquid film boiling on our functional structure is mainly constrained by the venting of vapor bubbles and increases with increase in flow rate before the liquid wicking limit is reached. The proposed strategy of employing liquid film boiling with minimum liquid transport distance may suggest a new design direction for efficient and sustainable two-phase cooling.

Modeling capillary wick irrigation system for greenhouse crop production

Microirrigation system is an efficient irrigation method that saves up to 60% of water and nutrients. However, the huge investment for installation of modern microirrigation systems is beyond of many smallholder crop producers. Therefore, this study focuses to model and develop the capillary wick irrigation system for greenhouse crop production to address this issue. The results revealed on tested wick materials that the maximum capillary height and maximum water holding capacity were observed in cotton bonded non-woven wick material compared to other materials (p > 0.05). Water level, wick length, and pot size linearly affected the discharge of wick emitter in hanging and buried capillary wick irrigation system (CWIS). In this study, the discharge equations for wick emitter of hanging and buried CWIS were successfully developed. Comparison of calculated discharge using newly developed equation with actual measured discharge of buried wick for potted tomatoes in greenhouse proved the accuracy of the equation. The effects of evapotranspiration were also found linearly on discharge of wick emitter and the relation between emitter discharge, pot size and evapotranspiration were lead the development of wick discharge linear curve (WDLC). WDLC introduced to estimate the required discharge for potted crops under CWIS. Then, solver program was used to successfully simulate the wick discharge for different potted crops under a CWIS. Outcomes of the study can be beneficial for smallholder farmers for greenhouse crop production for adopting CWIS as low-cost and highly efficient microirrigation system.

Effect of silk yarn parameters on the liquid transport considering yarn interlacing

Wetting and wicking are among the essential behaviors of fabric. Woven fabric is interwoven by the warp and weft yarn, and it can be considered as a yarn network. To clarify the wicking phenomenon of woven fabric and simulate its water transport, the wicking behaviors in the vertical and horizontal directions of six yarn samples were examined. The moisture movement of these interlacing silk yarns was clarified. The wicking behaviors of the silk yarn were found to increase at the first initial stage, and decrease with time until the yarn is saturated. The wicking length of the vertical direction revealed that the fiber and void areas in the silk yarn have an essential effect on water transport. Further, the wicking relationship between single and interlaced yarns was also discussed. The good relationship between the wicking length of single and interlaced yarns shows the possibility of predicting the wicking ability of the textile through the initial wicking ability of the single yarn in the future.

Optimization of AB Fertilizer for Plant Growth in Fertigation Using Central Composite Design

A plant needs to consume sufficient essential nutrients for production speed. This study investigated the optimum condition for water spinach growth of wick technique fertigation. Fertigation is a fertilizer application process in which the drip system mixes fertilizer within the irrigation water. The fertilizer solution is uniformly distributed in the irrigation system. The chosen method is a hydroponic method and suitable in an urban area with no soil for planting. Fertigation is also an easy and cost-effective method. The water spinach height’s optimum condition was determined through the central composite design (CCD) as the experiment (DOE) design. The critical factors selected for this study were the concentration of AB fertilizer and wick length. Obtaining an adequate AB fertilizer concentration is crucial because it will affect the growth of water spinach. The statistical analysis based on a CCD showed that 1.5 mL of AB fertilizer concentration (volume/volume) and 12 cm of wick length were the optimum conditions to achieve the best water spinach growth in 21 days. The CCD as a response surface method was proved to help obtain optimum water spinach plant growth conditions.

Application of a binary mixture of bio-extract on organic cotton fabric

Rosmarinus officinalis and Psidium guajava plant leaves are having rich sources of natural nutrients and phytochemical compounds. These phytochemical compounds inhibit the growth of microorganisms present in fewer animals and the human body. In this study, wound healing property was developed on organic cotton fabric using an equal ratio of Rosmarinus officinalis and Psidium guajava extract by following the pad-dry-cure method. The presence of phytochemical compounds was ascertained through Thin Layer Chromatography (TLC) and the existence of the functional group in the herbal extract was analyzed by Fourier Transform Infrared Spectroscopy (FTIR). Microcapsules are prepared from the herbal extract using an ionic gelation process and applied to organic cotton fabric. The size of the particle present in the microencapsulated extract was confirmed using Scanning Electron Microscope. The antibacterial activity of the herbal extract and treated cotton fabric was evaluated using the agar well diffusion and parallel streak method. A high zone of inhibition attained against Escherichia coli and Staphylococcus aureus indicates antibacterial potency of the extract. The thickness, stiffness, air permeability, vertical wicking length, and water vapour permeability properties were marginally affected after treatment. The wound healing analysis of the treated fabrics was carried out using an in-vitro wound healing scratch assay.

Smart polyethylene textiles for radiative and evaporative cooling

Polyethylene (PE) textiles can be engineered through structural optimization for efficient wicking and drying to simultaneously offer radiative and evaporative cooling. The great advantages of smart PE textiles beyond conventional textiles in energy savings, water conservation and low environmental footprint are systematically investigated to drive sustainable energy and environmental development of the textile industry.

Experimental study on flammability limits of electrolyte solvents in lithium-ion batteries using a wick combustion method

To quantify the flammability limits of organic electrolyte solvents used in lithium-ion batteries, a unique wick combustion system was developed in conjunction with limiting oxygen concentration (LOC) of candle-like flame, named wick-LOC method. By controlling the oxygen-nitrogen ratio of external flow of the wick diffusion flame, the flammability limits (LOC) of electrolyte solvents were determined experimentally. To provide reproducible results under specified conditions, the effects of axial flow velocity, exposed wick length and elapsed time after ignition on the wick-LOC were studied, and the proper experimental conditions were selected for further applications. To validate the reliability of wick-LOC in flammability evaluation, correlation analyses to other flammability properties (flash point, auto-ignition temperature, the heat of combustion and other types of LOC) were conducted. The wick-LOC method was then applied to quantify the flammability of mixed solvents. The linear changes of wick-LOC with mixing ratios were found in the mixture of linear and cyclic carbonates, while the non-linear trends were found in carbonate-ether mixed solvents. To evaluate the flame-retardant effectiveness of organophosphorus compounds (OPCs) as additives in electrolyte solvents, a series of tests were conducted. Results showed that small amounts of OPCs had significant flame-retardant effects, but the efficiency decreased with the higher OPC additions. The effectiveness of four OPCs was distinguished as well. The results of this work provided valuable information about the flammability limits of single and mixed electrolyte solvents, and it may be useful for designing electrolyte balanced in both performance and safety.

Caracterización de planteles de los sistemas de producción alpaquera de la sierra central del Perú

El propósito del estudio fue caracterizar los planteles de tres sistemas de producción alpaquera de la sierra central: empresas y cooperativas comunales (ECC), granjas comunales (GC) y asociaciones de ganaderos (AG). Se realizó del 2006 al 2008, comprendiendo el diagnóstico estático de 28 hatos alpaqueros, evaluación de 30 planteles comunales y estimación de parámetros productivos del núcleo central de reproductores de alpacas (NCRA), procedentes de 22 unidades ganaderas. Los resultados fueron: a) Diagnóstico estático: las ECC exhibieron mejores indicadores que los otros sistemas de producción, en manejo y producción de fibra (ECC 5.2, GC 4.9, AG 5.0 lb/alpaca), extensión de tierras dedicadas a la crianza de alpacas (ECC 3225, GC 1024, AG 195 ha), acceso al mercado (ECC nacional, GC y AG local) y porcentaje de animales registrados (ECC 10.5, GC 0.9, AG 0%); b) Evaluación de planteles: las ECC mostraron mejores indicadores que los demás sistemas de producción, en proporción de madres clase Súper (ECC 23, GC 5, AG 0%) y padres Súper (ECC 86, GC 52, AG 0%), conformación del animal (ECC buena, GC y AG regular), finura de vellón (ECC fina, GC y AG media a gruesa), pasto cultivado (ECC 100, GC y AG 0%) y condición de pastizal (ECC y GC regular, AG pobre); y c) Parámetros productivos del NCRA: las alpacas provenientes de planteles de ECC respondieron mejor que los otros sistemas de producción en proporción de alpacas madres de clase Súper (ECC 13, GC 8, AG 2%), peso vivo a la esquila (ECC 59.3, GC 58.9, AG 53.1 kg), vellón sucio (ECC 2.4, GC 2.2, AG 2.4 kg) y longitud de mecha (ECC 8.9, GC 6.9, AG 7.0 cm). Los resultados muestran que las ECC muestran mejores parámetros que los otros sistemas de producción evaluados en el estudio.

Spontaneous imbibition of liquid in glass fiber wicks, Part II: Validation of a diffuse‐front model

In Part I (Zarandi MAF, Pillai KM. Spontaneous Imbibition of Liquids in Glass‐Fiber Wicks. Part I: Usefulness of a Sharp‐Front Approach. AIChE J, 64: 294–305, 2018), a model based on sharp liquid‐front was proposed where a good match with the experimental data was achieved. However, the model failed to account for partial saturations in the wicks. Here, Richard's equation to predict liquid saturation is tried where the equation is solved numerically in 3D using COMSOL and analytically in 1D using Mathematica for glass‐fiber wicks after treating them as transversely‐isotropic porous media. As a novel contribution, relative permeability and capillary pressure are determined directly from pore‐scale simulations in wick microstructure using the state‐of‐the‐art software GeoDict. The saturation along the wick length is determined experimentally through a new liquid‐N2 based freezing technique. After including the gravity effect, good agreements between the numerical/analytical predictions and experimental results are achieved in saturation distributions. We also validated the Richard's equation based model while predicting absorbed liquid‐mass into the wick as function of time. © 2017 American Institute of Chemical Engineers AIChE J, 63: 306–315, 2018

Gravimetric measurement of solid and liquid fuel burning rate near and at the low oxygen extinction limit

A precision mass balance coupled with a variable oxygen flow tunnel/nozzle enables us to measure the burning rate of solid and liquid fuels as a function of ambient oxygen percentage all the way to the extinction limit. Two sample configurations have been studied. The first is a liquid fueled wick flame (ethanol tea lamp). The total burning rate (mass/time) is measured as a function of wick length and oxygen percentage. Near the low oxygen limit, limit-cycle flame oscillation has been found that can last for many minutes to hours. The averaged mass burning rate of the oscillatory flame is about one-half that of the steady flame occurring at slightly higher oxygen. In the second configuration, local burning rate (mass/area/time) of poly(methyl methacrylate) spherical shell samples have been measured in the flame stabilization zone. Each sample has a different amount of heat loss and a different oxygen limit. The critical burning rate at their respective oxygen limits are different. This implies that critical burning rate is not a property of the material alone and it should not be used as the only criterion to judge the extinction or the ignition of materials.

A novel method for blood-typing using nitrocellulose.

Blood wicking in its steady-state form, i.e. the uniform distribution of blood cells in plasma, is completely different from that in its coagulated form on a porous surface like paper. The hydrophilic property of the cellulose leads to a significant wicking of the blood cells on paper fibers after rinsing with isotonic solution. The difference in the wicking length of the blood cells in steady state and that in the coagulated form could be considered as a criterion to recognize the blood type in a paper-based kit. However, owing to the molecular structure of the nitrocellulose, a better process occurs while separating the coagulated blood from the steady-state form of cells. Therefore, it is possible to use the nitrocellulose for the blood-typing kit which leads to a simpler way to diagnose a blood type. Two series of experiments were performed on nitrocellulose membrane. First, antibody solutions and blood samples were sequentially absorbed on nitrocellulose strips, allowed to interact, rinsed with an isotonic solution and distilled water, and image processing performed on a digital picture of the remaining blood cells. The efficiency of the agglutinated blood cell fixation was quantified by red color intensity. Then, it was demonstrated that there is no considerable difference in fixation of agglutinated blood cells with rinsing using isotonic and nonisotonic solutions. This fact can be a considerable advantage over paper since it can eliminate the probable mistake from using unisotonic solution for rinsing. Second, owing to the nonwicking property of the blood cells on the hydrophobic nitrocellulose fibers, we employed another diagnostic criterion and investigated nitrocellulose blood-typing prototypes. The nitrocellulose blood-typing kit provides more simple, sensitive and trustworthy assay for rapid blood typing in situations with no access to laboratory facilities.

Soot measurements in candle flames

Soot volume fractions and soot temperatures have been measured for the first time on candle flames. Measurements on laminar steady flames were carried out using candles with wick diameters of 2, 3 and 4mm. Wick length was varied between 4 and 10mm. The shape of the candle flame was obtained from CH∗ spontaneous emissions. Measured flame heights show an increase with wick dimensions, approaching an asymptotic value for increasing wick lengths. Soot volume fractions were obtained from laser extinction measurements with the Modulated Absorption/Emission (MAE) technique. A deconvolution technique and a regularization procedure were applied to the data. Radial profiles of soot volume fractions increase when varying the wick dimensions; this effect is produced by the greater amount of fuel released by the wick. Radially integrated soot volume fractions were also calculated, presenting a similar behavior to the soot volume fraction radial profiles. The peak integrated soot volume fraction was found at approximately half the flame height, independent of the wick dimensions and burning rates. Soot temperature was obtained from emission measurements at two different wavelengths considering the attenuation of the soot particles in the optical path length. A deconvolution and regularization procedure was carried out in order to obtain temperature profiles for different heights in the flame. The observed increase in soot production and soot temperature profiles was directly related to the higher burning rate experienced by the candle. The results show that peak integrated soot volume fractions are proportional to both the mass loss rates and the flame heights.

Facile fabrication of polyester filament fabric with highly and durable hydrophilic surface by microwave‐assisted glycolysis

ABSTRACTPoly(ethylene terephthalate) (PET) fabric with highly and durable hydrophilic surface was fabricated using microwave‐assisted glycolysis. Sodium hydroxide (NaOH) as a catalyst was proven to be suitable for PET glycolysis under assistance of microwave. The modified PET fabric (0.5% NaOH, irradiation 120 s) showed high surface hydrophilicity with a contact angle of 17.4 ° and a wicking length of 19.36 mm. The exposure of the carboxyl‐ and hydroxyl‐end groups on the surface of PET and the introduction of etches were confirmed by Methylene Blue staining and field emission scanning electron microscopy (FESEM), receptively. Although the strength of PET fabric decreased after modification, it was still high enough for textile applications. The thermal properties of the modified PET fabrics were well maintained. The high hydrophilicity and its original properties of PET could be controlled by changing the irradiation time from 60 s to 120 s and adjusting the content of sodium hydroxide from 0.2% to 0.5%. These results suggest microwave‐assisted glycolysis with sodium hydroxide is an effective method for PET hydrophilic finishing. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44069.

Performance of the Solar Collector with Vacuum Tubes and Dual Heat Pipes Based on Wick Length Variation

The increasing number of non-renewable energy and the rising need of energy caused some global issue. We always interested to discuss how human being could create and improve an instrument that can extract energy from renewable energy resources, which is clean and applicable. One instrument that can extract energy from the sun is solar water heater. Solar water heater, consist of two main components. The first one is storage tank, and the other is solar collector. The purpose of this research is to design, manufacture, determine the performance of the solar collector with vacuum tubes and dual heat pipe based on the wick length variation. This experiment used a 150 Watt halogen lamp as the simulator of the sun. A copper fin was utilized to collect heat from the sun and transfer the heat to heat pipes. Adiabatic walls made from Styrofoam and plywood were set to prevent heat transfer to the environment due temperature difference. The performance of the heat pipe was investigated based on the wick length inside the heat pipe. The flow characteristic inside of the heat pipe and the thermal resistance depend on the wick length. The study found that the full-length wick heat pipe has the best performance with 0.37 K/W thermal resistance, and the efficiency of the system reach 34.95%. This is the highest value compared to the half-length and three-quarter length wick heat pipe.

Polyester fabric with inherent antibacterial, hydrophilic and UV protection properties

Polyethylene terephthalate (PET) yarn with multifunctional properties such as UV protection, antimicrobial property and cotton-like moisture transport properties was fabricated in a semi-commercial melt spinning machine. Effects of chemical modifications and additives on PET yarn with polyethylene glycol (PEG) and zinc oxide (ZnO) were studied and reported. It was found that ZnO imparts UV protection and antimicrobial properties and PEG helps to improve moisture management. Bacteriostatic activity above 3.5 was observed with ZnO incorporation. High wicking length of 15 cm was obtained as against 2 cm for control PET fabric of same construction.

Monoporous micropillar wick structures, II-optimization & theoretical limits

This article, the second of a two-part study, is aimed at finding optimal micropillar wick geometries and their theoretical performance limits. For the first time, the theoretical optimization results are experimentally verified. The permeability and capillary pressure models determined in the first part of this study are utilized in the optimization process. First, the existence of optimality is ascertained through constrained parametric sweeps of the individual variables in the wick performance model, which reveal the presence of optimal values of each variable for a specific combination of the other variables. Then, the overall optimization of wicks is accomplished through a genetic algorithm. It is established that a unique optimal geometry, i.e. a combination of diameter, spacing and height, exists at each wicking length. Finally, these results are used to determine the theoretical performance limits of micropillar array wicks. The results suggest that the theoretical performance limit is 3–4 times greater than the highest performance reported in literature.