Pile Height Research Articles

Compression behaviour of hand-tufted carpets: Part I–Effect of short-term static and dynamic loading

The effect of static and dynamic loading on the compression characteristics of hand tufted carpets has been studied using two types of pile materials. Wool tufted carpets are found to show better retention of thickness. Higher tuft density is found to assist retention of thickness, while higher pile height results in more thickness loss. Thickness loss is also found to be more at the initial impacts, while the recovery rate is found to be more at the initial stage

Propensity to self-heating ignition of open-circuit pouch lithium-ion battery pile on a hot boundary

The fire safety issue of Lithium-ion (Li-ion) batteries is an important obstacle for its market growth and applications. Although the open-circuit condition (e.g. storage, transport and disposal) accounts for the major part of battery lifespan, little research has investigated its self-ignition hazard during non-operating periods. In this work, we experimentally study the self-heating behavior of piled pouch Li-ion battery cells through the classical hot-plate experiments. Results show that the self-ignition of battery pile occurs under a hot plate temperature ranging from 199 °C to 265 °C, depending on the number of cells and environmental cooling. Thermal runaway always first occurs to the cell next to the hot plate and then propagates to upper cells. This critical temperature is increased by 20 °C under a good environmental cooling condition whereas it is reduced by 40 °C as the state of charge increases from 30% to 80%. Moreover, the critical plate temperature for self-ignition increases slightly with the height of battery pile, which is opposite to both hot-plate experiments of hydrocarbon materials and the oven experiments of battery. Therefore, the classical self-ignition theory may not be applicable for Li-ion batteries next to a hot boundary. This research reveals new self-ignition phenomena and helps understand the fire safety of Li-ion batteries in storage and transport.

Effect of some construction elements of terry towel fabrics on absorption property

The aim of this has been to study some of the construction elements of terry towel fabrics on the efficiency and ability of absorption for these kinds of fabrics. The specification of warp yarns is constant according to (count – material – density), and we used some different variables for wefts, and it represented in: 1- Different wefts materials: where we used three different wefts which are (cotton- viscose- microfiber). 2- Different weaves: where we used three different weaves on wefts for each repeat for every weave and which are (3 wefts, 4 wefts, 6 wefts). 3- Different pile height: where it was change on pile loop height on fabric surface Which are (130-160-190). The effect of these variables has been studied on absorption property for terry towel fabrics and statistical analysis has been performed for the results of absorption and discussion.

Options for Optimizing the Drying Process and Reducing Dry Matter Losses in Whole-Tree Storage of Poplar from Short-Rotation Coppices in Germany

For sustainable production of wood in short-rotation coppices and agroforestry systems, it is necessary to optimize the storage processes to achieve low dry matter losses together with low-cost drying. The harvesting of the trees can be carried out very efficiently with modified forage harvesters or tractor-powered mower-chippers. The wood chips produced can be dried naturally at low cost in open-air piles. However, this type of storage is connected with high dry matter losses of up to about one fourth in the course of seven-month storage. Although harvesting whole trees is connected with significantly higher costs, lower dry matter losses are to be expected from storing the trees in piles. Consequently, in this study, the storage and drying behavior of poplar under different German weather conditions and depending on the structure of the storage piles has been examined in detail. After a seven-months storage period, the trees still displayed moisture contents of 41–44% following an initial moisture content of 56% but achieved very low dry matter losses of only 4–7%. Moisture contents of 35–39% could only be achieved in October after a further two-months drying period under favorable weather conditions. All storage piles were built up on approximately 30 cm high support timbers for better ventilation. Additionally, covering the ground with a fleece did not have any influence on the drying behavior, nor did different pile heights. Smaller tree trunk diameters are not only connected with a higher share of bark or ash, but also thinner trunks tend to become damp again more quickly after rainfall. That is why whole-tree storage is suitable above all for medium or longer rotation periods with which, under favorable conditions, the higher harvesting costs can be compensated by a higher wood chip quality and lower storage losses.

Designing woven velour printed terry fabric for improved colour fastness

PurposeThe purpose of this paper is to investigate the effect of pick density, pile height and pile yarn count (both single- and double-ply yarn) on the colour fastness to crocking, colour fastness to washing, colour fastness to water of woven velour printed terry fabrics. These variables have also been optimized for developing high-quality fabrics.Design/methodology/approachVariables were selected on the basis of past research experience and samples were prepared according to the Box–Behnken design of experiments. The samples were tested for colour fastness to crocking, colour fastness to washing and colour fastness to water by following AATCC 8, AATCC 61, 2A and AATCC 107, respectively.FindingsThe colour fastness to crocking, washing and water of woven velour printed terry fabrics increases with the decrease in pile height and pick density. The colour fastness properties of the fabric increase with increase in fineness of the pile yarn count. Woven velour printed terry fabric with 16.25 picks per cm, 3.5 mm pile height and 16 Ne pile yarn will show best colour fastness. Woven velour printed terry fabric (plied pile yarn) with 16.25 picks per cm, 3.5 mm pile height and 2/24 Ne pile yarn will show best colour fastnessPractical implicationsProved a practical approach to control fastness properties of the fabric by changing fabric variables.Originality/valueColour fastness properties of woven velour printed terry fabrics have never been reported. The research work gives the better understanding to develop high quality of fabrics by reducing pile height and pick density. This will also reduce the cost of the fabric.

Callus Induction of Mangosteen (Garcinia mangostana L.) In Vitro with Addition of Growth Regulators

This research was conducted to determine the best combination of plant growth regulators on callus induction of shoot explants mangosteen (Garcinia mangostana L.). The research used complete randomized design (CRD) which is consisting of 12 treatments with 3 times repetitions. The parameters observed were time of callus formation, callus texture, callus color, callus pile height, callus surface area, callus weight, and callus performance. Data was analyzed by using ANOVA, and DMRT as follow up. The result showed that addition of plant growth regulators have effect on callus induction of shoot explant mangosteen (Garcinia mangostana L.). The best concentration and composition of media for induction of mangosteen callus is by giving sucrose 1,5 g / L + 2,4D 3 ppm because it was able to produce callus with the fastest time with a compact texture and color that is identical to green and white. The callus has 0.67a cm in height, 1.70a cm2 in width, and 0.51a g in weight. The callus performance is growing all over the surface.

Pineapple callus induction from Sipahutar North Sumatera Indonesia (Ananas comosus L.) with bud as a source explant

The preservation and development of Sipahutar pineapple is very important to do. One of the most effective ways is with tissue culture techniques. The aim of this research is to know the effect of 2,4-Diclorofenoxyacetic acid (2,4-D), kinetin, and interaction of both Plant Growth Regulator (PGR) to callus induction on pineapple (Ananas comosus L.) from Sipahutar Sumatera Utara Indonesia. The design of this study used a Factorial Completely Randomized Design, namely is 2.4-D with 3 doses of treatment (0, 1, 2 ppm) as the first and the second factor of kinetin with 3 doses (0, 0.5, 1 ppm). The observation process was conducted for 28 days and 35 days after induction. The parameters observed were the formation time of callus, callus color, callus biomass, and the height of callus pile. The results showed that 2,4-D, kinetin and interaction of 2,4-D and kinetin significantly influenced the time of callus formation, callus biomass, and significant effect on the height of callus pile. The time of callus formation is the fastest on day 8 after induction. The best of callus color is whitish green comes from 2,4-D 0 ppm and kinetin 1 ppm treatment. The highest biomass is 1.69 grams. The highest stack height of callus was 2.32 cm. The highest biomass, stack height, surface area of callus derived from the treatment of 2,4-D 0 ppm and kinetin 0 ppm.

Prediction of discharge flow rate beneath sheet piles using gene expression programming based on scaled boundary finite element modelling database

Sheet piles are of general water retaining structures. The discharge flow rate beneath sheet plies is an important parameter in the design of these structures. In this study, the Gene Expression Programming (GEP) as an Artificial Intelligence (AI) method is used for developing a model to predict the discharge flow rate. The input parameters include the sheet pile height, upstream head and hydraulic conductivity anisotropy ratio. In order to achieve better performance, the flow rate is normalized and selected as an output of the model. A database including 1000 cases are created from the Scaled Boundary Finite Element Method (SBFEM) for the seepage beneath sheet plies is employed to develop the model. The GEP-based model predictions demonstrate a reasonable agreement with the simulated data, which indicates the efficiency of the developed model. The results of the sensitivity analysis indicate that the upstream head is the most influential parameter in the discharge flow rate beneath the sheet piles. Furthermore, the outputs of the parametric analysis show the reasonable performance of the model in the prediction of normalized discharge flow rate.

Manufacturing and drop-weight impact properties of three-dimensional integrated-woven sandwich composite panels with hybrid core

This paper is concerned with the effect of core pile yarn hybridization on the low-velocity impact response of 3D integrated-woven sandwich composite panels. For this purpose, at first, hybrid yarn was produced by a co-wrapped technique that is composed of polyester and glass fibres as shell and core structure, respectively. Then, 3D-woven samples with glass and hybrid pile yarns were fabricated, and after the impregnation, the behaviour of fabricated samples under low-velocity impact was experimentally investigated. In order to characterize this new type of hybrid structure, the fabricated samples with different pile heights and pile distribution densities were subjected to low-velocity impact tests at an energy level of 8 J. The impact characteristics of all panels including the load–time and load–displacement curves, contact time, absorbed energy and extent of the damage have been studied. Also, the extent of damage is interpreted in terms of the compressive strength loss after the impact of samples. According to the results, in comparison with the homogeneous glass/epoxy composites, contact time and deflection increased in panels with hybrid pile yarn, whereas the impact load decreased for the hybrid one. On the other hand, hybrid samples have a lower impact index than the homogeneous glass/epoxy composites. The compression after impact test results showed that the residual strength in hybrid samples is higher than the glass/epoxy composites.

Effect of Particle Shape on Repose Angle Based on Hopper Flow Test and Discrete Element Method

The repose angle of granular material is an essential parameter to understand the microbehavior of the granular material and, then, to relate it with the macrobehavior. In this study, a self‐design large‐scale hopper flow test apparatus has been developed to measure the repose angle of the ballast using a fixed funnel method. Then, the numerical simulation using the realistic clump is compared with the experimental test to prove its validity. Meanwhile, the idealized clumps with custom shape parameters, including roughness of particle and ground, angularity, aspect ratio, and sphericity, were chosen to analyze the influences of particle shape on the repose angle. The results show that the angle of repose generally tends to increase with the increase of the friction coefficient of particles and the roughness of the ground. With the increase of the angularity from 0 to 4, the pile height and the repose angle increase. Meanwhile, the extended area decreases accordingly. For cuboid particles, with aspect ratio increasing from 1.0 to 1.67, the angle of repose increases firstly and then maintains a constant between aspect ratio 1.25–1.67. For ellipsoid particles, the angle of repose decreases, then reaches a minimum at aspect ratio around 1.3, and finally increases.

Exploring the reproductive ecology of the tropical semifossorial snake Ninia atrata.

Based on histological analyses and field studies, this research describes the reproductive ecology of a population of Ninia atrata snakes inhabiting an oil palm plantation. Furthermore, through a multivariate approach, we explored the main drivers of reproductive output in N. atrata. Results showed that prey abundance and food intake were crucial variables contributing to reproductive output. Multiple linear regression models showed that neonates had high sensitivity (R2=55.29%) to extreme changes in climate, which was strongly related to slug and snail abundance variability and microhabitat quality. Reproductive cycles were markedly different between the sexes, being continuous in males and cyclical in females. Despite this variation, reproductive cycles at the population level were seasonal semi-synchronous. Constant recruitment of neonates all year, multiple clutches, high mating frequency, and continuous sperm production characterized the reproductive phenology of N. atrata. In addition, a significant number of previtellogenic females presented oviductal sperm as well as uterine scars, suggesting a high precocity in the species. The main drivers of reproductive output also differed between the sexes. In females, clutch size and secondary follicle variability were highly related to stomach bolus volume, fat body area, and body mass. In males, height of piles of palm leaves and body mass, rather than intrinsic reproductive traits, were the main drivers of sperm production. Nevertheless, in both cases, the relationship between body mass, prey abundance, and food intake suggests that N. atrata follows the income breeding strategy to compensate for reproductive costs and to maximize fitness.

Modelling of acrylic cut-pile carpet compression properties by means of expert systems based on carpet structural parameters

Compression properties of carpet are a detrimental factor influencing carpet wear performance. In fact, carpet compression behavior determines carpet serviceability which in turn affects carpet appearance. Therefore, it is important to predict the carpet compression behavior in order to reduce the product cost. In this paper, a fuzzy logic model for prediction of compressional properties of acrylic cut-pile carpets is implemented in terms of the carpet structural parameters including carpet pile density, linear density of pile yarns and carpet pile height. In order to provide experimental data, six different acrylic cut-pile carpet samples fabricated by using six different acrylic spun pile yarns with yarn count of 18/3, 21/3, 27/3, 30/3, 33/3 and 36/3 Nm. Half of each provided carpet subjected to re-shearing process. All 12 carpet samples in two different cases (normal and reduced pile height) have been tested by standard carpet static and dynamic loading tests to measure thickness-loss as one of compression properties. Fuzzy logic model has been implemented and improved using genetic algorithm. Results show that correlation coefficients of model predictions with experimental values are 0.97, 0.98, 0.98 and 0.98 for carpet thickness-loss after low dynamic, high dynamic and static loading with short and long relaxation times, respectively. Also, linear regression trend between predicted and experimental values represented with a slope near to 1 and almost small bias (intercept). The result indicates that the developed fuzzy logic model is a reliable model predicting the acrylic cut-pile compression behavior.

Mathematical Modeling of Heat-Exchange Processes in Outdoor Storage of Frozen Coal

The modeling procedure is developed to describe heat-exchange processes in outdoor summer storage piles of frozen coal produced in winter. This procedure takes into account thermophysical properties of coal and the pile bottom soil, pile structure, climatic factors and the presence of a heat-insulating coating over the pile. In terms of central Yakutia, it is shown that maximum transition of coal from frozen state (piling in January-March) to thawed condition at the pile height more than 5 m will make 25-35% by the end of the warm season (beginning of October). Application of simple and available heat-insulating materials can reduce thawing intensity by up to 2 times. Natural cold weakens the aggravating effect of oxidizing processes on coal quality in long-term storage of coal and its shipment to remote and hard-to-reach places.

Ice interaction processes during ice encroachment

Ice encroachment is the accumulation of ice atop a platform and results when ice drifts against a platform. Most often this occurs in shallow water but in principle can occur in deep water if the ice drift length is long enough. As the ice drifts against the platform it is broken and generates rubble and ice piles in front of the platform, and with sufficient drift duration blocks of ice can be pushed up and onto the platform. This must be taken into account when designing structures in the Caspian Sea and other shallow water areas where there is significant ice drift. Ice can encroach on the structure by ice ride-up and pile-up. Consequently, the height and extent of the ice piling up on top of the structures must be taken into account in designing the layout, and often a protective ice encroachment zone is made all around the structure. The aim of this paper is to provide an outline of various approaches and parameters to consider where ice encroachment may occur. The study is supported by analysis of dedicated ice model test data, numerical simulations using Discrete Element Models, and full scale data of ice encroachment events. The intent is to give an understanding of the physics of ice encroachment and support in the design of shallow water offshore structures. In particular, the results indicate the importance of ice strength in the process and especially the maximum pile height. If the ice is weaker, the pile grows horizontally in a seaward direction in front of the structure, and conversely, stronger ice forms ice encroachment with greater vertical and also horizontal extent on the platform. The results also show that once the maximum pile height is established subsequent drift enlarges the seaward extent of the rubble pile in front of the structure.

An experimental and numerical study of the aeolian erosion of isolated and successive piles

Open storage yards at industrial sites usually comprise several piles of granular materials, representing a particulate matter source that may significantly deteriorate air quality. The aeolian erosion of stockpiles is affected by changes in airflow patterns due to the pile shape and the presence of nearby piles or buildings. The aim of this study was to analyse the impact of wind erosion of successive parallel stockpiles on flow behaviour and particle emissions. A wind tunnel experiment was conducted in six configurations: one isolated pile and two successive piles separated by gaps of 0.9h and 1.8h (h is the pile height) oriented to 60° and 90° with respect to the main wind flow direction. The particles in the piles had a bimodal particle size distribution consisting of sand that was erodible (white) and non-erodible (black) in the investigated velocity range. The contrasting colours enabled the visualisation of the non-erodible sand accumulation. The mean field of the wall shear stress distribution and flow pathlines predicted by numerical simulation were associated with the experimental erosion patterns. The emitted mass was experimentally quantified as the difference between the initial and final stockpile weights. Downstream pile had a large impact on the aeolian erosion as it was highly eroded as a result of the impact of the particles emitted from the upstream pile. The emissions of the two consecutive stockpiles were greater than twice the emissions from an isolated stockpile for both orientations. Additionally, emissions were lower for configurations in which the piles were perpendicular.

Effect of Pile Height on the Mechanical Properties of 3D Woven Spacer Composites

Three-dimensional (3D) woven spacer fabric is produced by connecting two woven fabric layers with the vertical pile yarns in the center part. Their composites have great potential for use in construction, automotive, marine, and aerospace applications due to outstanding mechanical properties. In this paper, 3D woven spacer fabrics with three thickness levels (4 mm, 10 mm and 20 mm) made of E-glass fibre, were used. Then 3D woven spacer fabrics were fabricated into their corresponding composites by hand lay-up technique using green epoxy resin. Characterization was done at both stages i.e. fabric and composite. Bending length and modulus of 3D woven spacer fabrics were decreased while the stiffness of the fabric was increased with increase in sample thickness. While in 3D woven spacer composites, 20 mm thick composite was more needle penetration resistant as compared to the 10 mm and 4 mm thick composites. Flexural and slow velocity impact performance of the 3D woven spacer composites was reduced with the increase of sample thickness. Flexural behaviour was better in weft direction as compared to the warp direction in all samples. Furthermore, 4 mm thick composite showed the highest value of energy absorbed and least deformation during the drop weight impact test.

Inclined granular flow in a narrow chute.

In this paper we presents a detailed description of granular flow down a flat, narrow chute using discrete element method simulations, with emphasis on the influence of sidewalls on the flow. The overall phase diagram is provided and it is found that there are four flow regimes (no flow, bulk flow, surface flow, and gas flow). The H̃stop curve is very complicated and quite different from that in the case without sidewalls. The effective friction coefficient [Formula: see text] increases with pile height H̃ and a surface flow occurs when the inclination angle [Formula: see text] exceeds a critical value. The profile of [Formula: see text] shows that the [Formula: see text] rheology is valid in boundary layers. Furthermore, [Formula: see text] increases with the velocity of particles and there is a saturation to a nonzero value in static heap. For small H̃, the static heap vanishes and there is a bulk flow. A similarity between basal particles and sidewall particles indicates a universal role of the boundaries. In this bulk flow, there is a transition of the velocity profile with wall friction [Formula: see text]. When [Formula: see text] is large, the velocity is linear and decreases with increasing height. With small [Formula: see text], the velocity is nonlinear and the flow rate is roughly proportional to H̃3/2.

Effects of tool wear on surface micro-topography in ultra-precision turning

In ultra-precision turning of large optical components, the surface quality deterioration caused by tool wear has severely restricted the optical performance of these components. To investigate the effects of tool wear on surface micro-topography, this paper conducts an experimental study on the ultra-precision turning of copper. The wear characteristics of the diamond tool and the micro-topography of the ultra-precision turned surface at different cutting distances are discussed and evaluated. The plastic deformation behavior of the workpiece material is investigated at various cutting parameters and tool wear conditions. Furthermore, the power spectral density (PSD) and the diffraction optical characteristics of the machined surface are achieved and analyzed quantitatively. The experimental results show that during diamond turning of copper, the tool wear is mainly characterized by the micro-breakages on the tool edge when the cutting distance is less than 24 km. With the increase of the cutting distance, the micro-breakages gradually develop into the continuous wear land, and the enlarged wear area is attributed to the cumulative cleavage fractures and uniform mechanical wear. Moreover, the increased tool wear can result in more pronounced periodic surface micro-topography and greater height of the material pile up, which will deteriorate the optical performance and enhance the diffraction effect of the ultra-precision turned surface.

Pile age and burn season influence fuelbed properties, combustion dynamics, fuel consumption, and charcoal formation when burning hand piles

Piling and burning is widely used to dispose of unmerchantable debris resulting from thinning in forests throughout the western United States. Quite often more piles are created than are burned in a given year, however, causing piles to persist, accumulate, and age on the landscape. The effects of burning piles of increasing age has not been studied. We examined the effects of time since construction (i.e., pile age, in roughly six month increments for two years) and burn season (fall and spring) on fuelbed properties, combustion dynamics, fuel consumption, and charcoal formation for hand-constructed piles in thinned ponderosa pine-dominated sites in New Mexico (n = 50 piles) and Washington (n = 49 piles). Piles compacted over time similarly for both study sites, losing approximately 15% of their height annually for the first two years following piling. Peak flame height decreased and the duration of flaming combustion increased with increasing pile age for both burn seasons in New Mexico, yet depended on burn season in Washington. Increasing fuel moisture and compaction reduced peak flame height and increased flaming duration modestly for both sites. Peak flame height was reduced 6–7 cm and flaming duration increased 0.9–2.3 min for every percentage increase in small fuel moisture. Similarly, peak flame height was reduced 4–5 cm and flaming duration increased 0.6–0.8 min for every percentage reduction in pile height. Fuel consumption was high, averaging 90% in New Mexico and 95% in Washington. Fuel consumption patterns differed between locations, however; fuel consumption decreased with age and was slightly higher for spring than fall burns in New Mexico, whereas, neither pile age nor burn season affected fuel consumption in Washington. Charcoal formation as a fraction of pre-burn pile weight averaged 2.8% in New Mexico and 1.2% in Washington, and was not affected by pile age or burn season. Fuel consumption and charcoal production were unaffected by fuel moisture or compaction levels at either site. Findings from this study will inform fuel and fire managers about the potential effects on fire behavior, fuel consumption, and charcoal formation of burning piles of different age in different seasons under different environmental conditions.

Seepage through homogeneous earth dams provided with a vertical sheet pile and formed on impervious foundation

Abstract This paper implements a 2D finite element numerical model to study the effect of adding a vertical sheet pile to an earth dam’s cross section that is formed on impervious foundation. The study aims to determine the effect of existence of sheet pile as well as its height and location on the total seepage discharge and velocities through the dam’s cross section. The research program involves different scenarios for the height and location of the sheet pile and tailwater depth. The results show that the sheet pile’s height has greater effect on the total seepage discharge rather than its location. Increasing the sheet pile’s height decreases the total seepage discharge by a ratio up to 34.4% of its value without sheet pile for (HSP/H) = 0.75. The maximum velocity was detected at the sheet pile’s upper end; and its value is directly proportional to the height of the vertical sheet pile.