Liner Production Research Articles

Daily Light Integral and Far-Red Radiation Influence Morphology and Quality of Liners and Subsequent Flowering and Development of Petunia in Controlled Greenhouses

Petunia stands as the top-selling bedding plant in the U.S., and improved lighting control in greenhouses holds the potential to reduce crop production time and optimize crop quality. This study investigated the impact of four distinct daily light integral (DLI) conditions with and without supplemental far-red (FR) radiation on the growth of petunia liners and subsequent development of finish plants. Two experiments were conducted in spring (9 April to 18 June 2021) and winter (28 October 2021 to 6 January 2022). Petunia cuttings were rooted in a common environment and then transferred to four greenhouse sections with different DLI treatments: 6, 9, 12, and 15 mol·m−2·d−1 for four weeks. Within each DLI condition, half of the plants were exposed to 28 μmol·m−2·s−1 supplemental FR radiation for 16 h daily (equivalent to 1.61 mol·m−2·d−1 light integral). The number of flower buds and open flowers were tracked daily. Representative liners were destructively harvested and evaluated after four weeks of lighting treatments. The remaining plants were transplanted and moved to a common DLI condition of 15 mol·m−2·d−1 for an additional three weeks before being destructively harvested and evaluated as finish plants. The primary finding reveals the promoting effect of DLI on flowering, branching, morphology, and biomass accumulation of petunia liners, with many effects persisting into the finish stage. A threshold DLI of 9 mol·m−2·d−1 was identified, as lower DLI (6 mol·m−2·d−1) resulted in extensive stem elongation, rendering the plants unmarketable. Higher DLI levels were found to be optimal in terms of flowering and morphology. Supplemental FR accelerated flowering by up to three days in the summer experiment and up to 12 days in the winter experiment. However, FR had limited impact on the number of flower buds and open flowers, branching, and shoot and root weight of the finish plants. Interactions between DLI and FR were observed on some parameters, whereby FR effects were more pronounced under lower DLI. Overall, both higher DLI and supplemental FR exhibited beneficial effects, but DLI had a more pronounced effect. Thus, DLI during petunia liner production appears more important than adding FR. This study well simulated the commercial propagation and production of petunia plants, providing practical insights for decision-making regarding lighting strategies.

Real-time ultrasonic water level IoT sensor for in-situ soil permeability testing

Soil permeability tests require a time series of water level measurements to determine system losses, including both infiltration and evaporation. Laboratory measurements of flow are standardised by international regulations such as ASTM International, ISO or UNE, but field measurements are not as well described and in some cases may require definition and specification of test conditions. This is the case for geosynthetic clay liner (GCL) products, where permeability is assessed by a laboratory measurement using a flexible wall permeameter as defined in standard test method D 5887-04. This method is not able to evaluate the performance of such products in the field and therefore cannot guarantee their ability to be used for the repair of landfill liner overlays. For this reason, we have defined a field test in a confined steel ring and developed a real-time ultrasonic IoT device to evaluate water losses over a period of time. The test method was applied in Mallorca (Spain) and as a result the quality of a landfill cover repair solution was evaluated, the corresponding civil works were carried out and the basis for future field measurements of soil permeability tests on different materials and conditions was established.

Transformation of waste carbon fiber prepreg into sustainable composites: Application in the automotive industry components

AbstractCarbon fiber (CF) prepregs are employed in the manufacture of many different aeronautical structural and non‐structural components. Following the cure of the prepregs in molds, trimming is generally used to give the final shape to the components. Considering the aircraft's vast surface area and the use of multiple prepreg layers in each component, an extensive amount of carbon fiber prepreg is discarded. The unique characteristics of carbon fibers render this CF waste highly valuable and requires its efficient recycling. Cured waste CF prepregs were milled and processed in this research to produce chopped carbon fibers for use in the novel composite development. The matrix material used in the composites was selected as recycled polypropylene sourced from old surgical masks, which highlighted the sustainability of the developed composites. To enhance the quality of the fiber‐matrix interface and improve the impact resistance of the composites an anhydride‐grafted polyethylene (Fusabond) was employed in small quantities. From mechanical characterizations, synergistic effects of the fillers were observed. Besides, compositions containing CF and Fusabond are found more impact resistant than neat matrix. In addition, the use of carbon fibers increased fracture toughness of the matrix through various mechanisms including fiber bridging, fiber pullout, and matrix plastic deformation identified by scanning electron microscopy fractography. Thermomechanical characterizations using dynamic mechanical analysis revealed that carbon fiber raises the neat matrix's glass transition temperature. The developed materials are intended to be employed in the automotive industry to produce inner fender liners, with an optimal composition determined by an optimization research.Highlights Carbon fiber (CF) derived from aerospace fresh scraps significantly improved the mechanical properties of the polymer matrix. Anhydride‐grafted polyethylene incorporation remarkably enhanced the impact resistance of the polymer. CF demonstrated a bridge effect and improved the fracture toughness of the composites. The use of recycled CF presents encouraging prospects in the automotive industry for the production of inner fender liners.

FRACTIONATION OF OLD CORRUGATED CONTAINERS FOR MANUFACTURE OF TEST LINER AND FLUTING PAPER

Old corrugated container (OCC) pulp was fractionated and it was found that the longer fiber fraction represented 76.54% and the short fiber fraction – 21.3% of the OCC pulp. The fiber length was 1.22 mm for the long fiber fraction and 0.6 mm for the short fiber, which was longer and shorter, respectively, than the fiber length of the whole OCC pulp (0.95 mm). In addition to fibers in pulp, the cellulosic microparticles that pass through a mesh screen or a perforated plate with a hole diameter of 76 μm, called fines, also have an impact on the properties of the final paper product. The fines content in both longer and shorter fiber fractions was lower than in the whole OCC pulp, consequently, drainage resistance (°SR) in the longer fiber fraction decreased to 14 from 21 in the whole OCC pulp. The air permeability and papermaking properties of the longer fiber were higher than those corresponding to the whole OCC and shorter fiber pulp. Therefore, the longer fraction of pulps can be used to manufacture test liner products and the shorter fiber fraction – for fluting paper.

Use of Artificial Intelligence to Analyze Liner Production

Use of Artificial Intelligence to Analyze Liner Production

Mechanical and Chemical Behaviour of Water Treatment Sludge and Soft Soil Mixtures for Liner Production

Background: Clay-based and geosynthetic liners are generally used as hydraulic barriers in solid waste disposal facilities, mining tailing ponds, and soil-based wastewater treatment technologies, avoiding the leaching of hazardous compounds into subsoil and groundwater. Water treatment sludge (WTS) is a water treatment plant (WTP) residue which due to hydraulic properties seems to decrease the permeability in WTS:soil mixtures and may become an alternative material to produce sustainable waste-based liners. Objectives: This research aims to characterize and analyse physical, chemical and mechanical parameters of a WTS, a soft soil and four mixtures WTS:soil following 05:95%, 10:90%, 15:85%, 20:80% ratios, Thereby, evaluating the best ratio for producing waste-based liners for civil engineering applications. Methods: The geotechnical characterization was performed for particle size distribution, specific surface, specific gravity, Atterberg limits, and Normal Proctor compaction; chemical composition due to oxides analyses through X-ray fluorescence (XRF), mineralogical description by X-ray diffraction (XRD) and scanning electron microscope (SEM) with energy dispersive spectrometer (EDS) coupled for imaging; and mechanical behavior performing - –oedometric consolidation, consolidated undrained (CU) triaxial, and falling head permeability. Tests were conducted for all mixtures, the soil, and WTS, with pointed-out exceptions. Results and Discussion: The results showed that the fine-grained WTS filled the soil voids but rearranged soil particles, thus, compacted dry unit weight decreased with WTS addition, probably due to its chemical composition with high amounts of aluminium and silica. The compressibility of the compacted mixtures did not differ significantly compared to the soil, while the shear strength analysis demonstrated a reduction in cohesion and an increase in the effective internal friction angle proportional to WTS addition. Hydraulic conductivity increased with WTS until 10% of residue introduction, decreased for 15%, and continued to decrease for 20%, reaching optimum permeability at 15%. Conclusion: The incorporation of WTS can improve or just not interfere with soil’s properties to be used as liner material in solid wastes storage facilities, mining ponds and soil-based wastewater treatment technologies. Furthermore, 15% of WTS (15:85% mixture) incorporation provided the best results meeting the hydraulic conductivity requirement for liner materials, i.e., equal, or lower than 10-9 m/s. The reuse of WTS for this purpose would allow producing a new added-value material in the scope of circular economy.

Ex Vitro Rooting of Cannabis sativa Microcuttings and Their Performance Compared to Retip and Stem Cuttings

There is demand for micropropagated Cannabis sativa liner plants, because they are uniform, vigorous, and pathogen free; however, availability is limited because of challenges with in vitro culture decline and ex vitro rooting. Ex vitro rooting success of microcuttings was evaluated for ‘Abacus’ and ‘Wife’ when cultures were 6, 9, 12, 15, and 18 weeks old from initiation. Microcuttings of ‘Wife’ harvested from 6, 9, and 12-week-old cultures rooted at or above 80%, but rooting declined to 50% and 30% for 15- and 18-week-old cultures, respectively. Rooting for ‘Abacus’ remained relatively constant between 47% and 70% for microcuttings harvested from 6- to 18-week-old cultures. ‘Wife’ plants grown from microcuttings, stem cuttings, and retip cuttings (cuttings taken from new shoots on recently micropropagated plants) had equivalent total shoot length, number of shoots, and flower dry weight, whereas micropropagated ‘Abacus’ plants had less shoot length and flower dry weight than plants from stem cuttings. However, when micropropagated ‘Abacus’ plants were provided an extra week of vegetative growth to reach an initial size equivalent to stem and retip plants, all plants performed the same. Propagation method did not change cannabinoid content for both ‘Abacus’ and ‘Wife’. Retip cuttings of ‘Abacus’ and ‘Wife’ rooted at 76% to 81% without rooting hormone, which is comparable to rates reported for stem cuttings of C. sativa treated with rooting hormone. Propagators should consider retipping to expand their liner production, because retips root well and possess the same desirable attributes as micropropagated plants.

Тенденції розвитку та конкурентна структура ринку целюлозо-паперової продукції України

Options of use of cardboard and paper packaging for goods and meeting the population's needs in hygiene products depends on the development of the pulp and paper products market. It is established that there are more than 2,5 thousand enterprises in the Ukrainian market of pulp and paper products yet 50 % of all products are produced by the 42 largest enterprises. The analysis of statistical data shows that the import of uncoated paper and cardboard significantly exceeds the export. The import of corrugated paper and cardboard, on the contrary, is lower than the export and is less than 1 %. Imports of household and sanitary paper are approximately equal to exports, but we can note its growth during 2020. Insignificant production of domestic pulp and wood pulp makes the Ukrainian pulp and paper industry very dependent on imports of raw materials. During 2015–2020, the production and import of household and sanitary paper show a steady upward trend, and the production, export, and import of uncoated and corrugated paper and cardboard are characterized by instability. Therefore, Ukrainian pulp and paper industry enterprises need to increase the number of waste collection points and to use innovative technologies to process straw for paper production. Coronavirus and quarantine restrictions in 2020 led to an increase in waste paper prices in Europe, first due to limited quantities and then due to growing demand. These prices increased in 2021 and not only in Europe but also in Ukraine, which causes rising prices for pulp and paper products. Analysis of the box cardboard market in Ukraine shows that in 2020 it was occupied by a large share of PJSC «KKPK» – 17 %, its share in the market of recycled coated cardboard is even greater – 44 %. There is strong competition in the market of liner products, which includes towels and toilet paper, but in 2020 it also retained the position of the leader of PJSC «KKPK», its share in this market was 42 %. Increased competition in the market of pulp and paper products forces its producers to pay more attention to the promotion of their products, including using the Internet. As part of the improvement of Internet communications, it is advisable to conduct SEO of the enterprise's website in order to increase traffic and convert visitors into customers by increasing the rank of the website. It is also advisable for manufacturers to create promotional websites for individual brands of their products in order to disseminate information about the company's paper products to target audiences. For promotional websites, considerable attention should be paid to the quality of advertising texts.

Investigation of the mechanical properties and corrosion behaviour of hybrid L 80 Type 1 and duplex steel joints produced by magnetically impelled arc butt welding

In the field of deep geothermal energy, the mono-tube design will be increasingly used in the future, as significant cost savings can be expected in the production of boreholes up to depths of 6000 m. The previously used bolting of the pipe lengths by means of sleeves contributes significantly to the construction costs. In addition, there is an increased risk of failure for the sleeve bolting, especially if different materials have to be used in different layers for the purpose of increasing the corrosion resistance. Magnetically Impelled Arc Butt Welding (MIAB) was used for direct welding of pipe segments with complete elimination of socket bolting. In the process, the casing material (L80 Type 1), which is a cost-effective standard material, and a corrosion-resistant duplex steel (1.4462) were hybrid welded. The results show excellent properties both in terms of mechanical properties and corrosion resistance. It is shown that the advantages of the MIAB process in joining these different materials can successfully overcome the metallurgical challenges. This new approach for the production of borehole liners can contribute significantly to cost reduction in the construction of geothermal boreholes.

Product Processing Quality Classification Model for Small-Sample and Imbalanced Data Environment.

With the rapid development of machine learning technology, how to use machine learning technology to empower the manufacturing industry has become a research hotspot. In order to solve the problem of product quality classification in a small sample data and imbalanced data environment, this paper proposes a data generation model called MSMOTE-GAN, which is based on Mahalanobis Synthetic Minority Oversampling Technology (MSMOTE) and Generative Adversarial Network (GAN). Among them, MSMOTE is proposed to solve the problem of the sample biased to the majority class expanded by methods such as GAN in a sample imbalanced environment. Based on the traditional SMOTE method, the sample distance measurement method is modified from Euclidean distance to Mahalanobis distance, taking into account the correlation between attributes and the influence of dimensions on the sample distance. In the data generation model, MSMOTE is used to balance the positive and negative samples in the data. GAN generates fake data with the same distribution as the original data based on a balanced data set and expands the sample size to solve the problems of overfitting and insufficient model expression ability that occur when the sample size is too small. The quality classification framework of water heater liner based on the data generation model and Random Forest is constructed, and the process of the quality classification of water heater liner under the environment of small sample data and imbalanced data is fully described. This paper compares the MSMOTE-GAN model, Bootstrap, and tableGAN on the water heater liner production line data set and the public data set. The experimental result shows that the expanded data set of the MSMOTE-GAN model can effectively improve the performance of the classification model.

MICROSTRUCTURE, MECHANICAL PROPERTIES AND GEOMETRY OF A MODEL BATCH OF SEMI-SPHERICAL STEEL LINERS INTENDED FOR USE IN THE EXTRACTIVE INDUSTRY

The article presents the results of investigation of the microstructure and mechanical properties of Fe-based materials intended for the production of semi-spherical liners for experimental shaped charges. The tests were carried out on samples taken in three directions in relation to the rolling direction: 0°, 45° and 90°, of the following materials: cold-rolled sheets made of DC04 steel, hot-rolled sheets made of 04J steel, and cold-rolled strips made of 004G steel developed at Łukasiewicz – IMŻ and annealed at 650°C. Semi-spherical drawpieces with a diameter of 106.4 mm, intended for liners, were made of the sheets with the use of cold stamping. Tests of the microstructure and HV hardness of samples taken from the test batch were carried out on cross-sections along the pressing direction and the model batch – on sections transverse to the stamping direction The geometry of the model batch drawpieces was also measured. The ferrite grain size evaluation was performed according to the ASTM E112 standard using μgrain software with a grain size evaluation module using counting the number of intersections of grain boundaries with a circle.

An equation for hole-spanning design of underground cast iron pipes lined with polymeric liners

Defects such as through-wall holes may significantly affect the performance of cast iron pipes lined with polymeric liners. Literature review reveals that the hole spanning design formulae in the Appendix X1 of ASTM F1216 (2016), also adopted in AWWA (2019), produce conservative results for holes with diameters smaller than the cut-off value defined in ASTM F1216 (2016) and AWWA (2019) for partially and fully deteriorated pipes but unconservative results for holes with diameters larger than the cut-off value, and the effect of holes on the mechanical behaviors of lined water pipes has not been thoroughly investigated. This paper aimed to address the issue in the hole spanning design formulae in ASTM F1216 (2016) and AWWA (2019), and numerically investigated and quantified the effect of holes in cast iron host pipes on the performance of lined pipes. A wide range of pipe dimensions, hole diameters, liner modulus, liner wall thickness, internal pressure and friction coefficients at the interface between the cast iron pipe and liner were considered. An equation for the maximum stresses in polymeric liners was derived based on the numerical results. It was found that the maximum stress in the polymeric liner increases with the diameter of the hole in the cast iron pipe until the hole size reaches a threshold level where the effect of hoop stresses takes over and the maximum stress will tend to plateau. It was also found that increasing the friction coefficient, the ratio of pipe modulus to liner modulus and the liner wall thickness will reduce the maximum stress in the liner. The outcome of this study can assist engineers in more accurate hole spanning design of polymeric liners for deteriorated cast iron pipes and quantifying the size of an unacceptable hole for a given host pipe and a liner product.

Automated ebb-and-flow subirrigation accelerates citrus liner production in treepots

Over the past decade, citrus production has sharply decreased in Florida because of citrus greening or Huanglongbing (HLB), a disease that reduces fruit yield and quality and eventually kills the citrus trees. With the increased mortality and need to resetting trees, the demand for healthy trees from citrus nurseries has risen drastically in the last few years. To meet the demand and accelerate tree growth, the citrus nursery industry should use modern horticultural practices such as more efficient irrigation methods, fertigation, and more vigorous rootstocks. This study evaluated the effect of subirrigation systems in tree production time, water and fertilizer inputs, and plant growth of commercial citrus rootstocks cultivated in treepots. We tested five irrigation methods [three ebb-and-flow subirrigation systems triggered at specific volumetric water contents (θ, 0.24, 0.36, and 0.48 m3 m−3), capillary mats, and a conventional drip irrigation system], and six commercial rootstocks (Kuharske, UFR-2, UFR-16, US-802, US-812, and X-639). The experiment was arranged in a split-plot design, with the main plot consisting of the five irrigation methods and sub-plots the different rootstocks. Ebb-and-flow subirrigation benches conserved 98% more water than conventional drip irrigation. Rootstocks grown under ebb-and-flow systems reached adequate stem diameter for grafting four weeks before the drip irrigation. Pummelo hybrids used in this study (UFR-16, UFR-2, and US-802) were 55% taller, 24% thicker, and 150% heavier on biomass production than the other varieties tested, irrespective of the irrigation method utilized. Although the substrate electrical conductivity was higher in all subirrigation methods, the values were below 1 dS cm−1, not causing symptoms of osmotic stress in plants. Our results show that the ebb-and-flow subirrigation system at θ of 0.24 m3 m−3 is the best option for accelerating citrus growth in treepots with peat: perlite substrate and to conserve water in Florida nurseries in comparison to capillary mats and drip irrigation.

Manufacturing Acetabular Liner UHMWPE using CNC Milling

Ultra High Molecular Weight Polyethylene (UHMWPE) is a biomedical polymer that is useful in the orthopedic field as a bearing component in artificial hip joints. In general, these polymers pair up and rub against each other with metallic biomaterials, namely 316L stainless steel, cobalt chromium (CoCr) and titanium, which can cause material wear problems. One way to increase the wear resistance of UHMWPE is through the manufacturing process. The purpose of this research is to manufacture acetabular liner products using a CNC milling machine to obtain high surface quality and dimensional accuracy. The CNC milling machine used is the type of YCM 1020 EV 20. The manufactured specimen is then measured for roughness and dimensional accuracy. Based on the measurement results, it is found that the acetabular liner specimens from the CNC milling process are still in accordance with the standard ASTM standard (F 2033-12).

Controlled Turning Process for the Production of Friction-Reduced Cylinder Liners with a Defined Free-Form Geometry

Controlled Turning Process for the Production of Friction-Reduced Cylinder Liners with a Defined Free-Form Geometry

Automated ebb-and-flow subirrigation conserves water and enhances citrus liner growth compared to capillary mat and overhead irrigation methods

Most citrus nurseries in Florida, USA use overhead irrigation, but subirrigation methods, including ebb-and-flow and capillary mats, have been shown to conserve water and accelerate plant growth relative to overhead irrigation for other nursery species and may be a viable alternative to overhead irrigation in citrus liner production. The objectives of this study were to (1) automate an ebb-and-flow system for citrus liner production using capacitance sensors, and (2) evaluate how subirrigation and overhead irrigation methods affect water use, plant growth parameters, and substrate chemical properties. A study was conducted from 22 May to 23 September 2018 in which liners of six commercially important rootstock cultivars in cone-shaped containers were subjected to one of the following irrigation methods: ebb-and-flow triggered at substrate volumetric water contents (θ) of 0.24, 0.36, or 0.48 m3 m−3, capillary mats, and overhead irrigation. Capacitance sensors successfully monitored irrigation throughout the study. Ebb-and-flow benches used substantially less water (~411 L) than either capillary mats (13,098 L) or overhead irrigation (3193 L). By the end of the study, rootstock cultivars propagated using subirrigation methods were approximately 22% taller with 7% more total biomass than plants subjected to overhead irrigation. Additionally, plant growth at the 0.24 m3 m−3 threshold used to trigger ebb-and-flow was as great or greater than growth at 0.36 and 0.48 m3 m−3 thresholds. During the final five weeks of the study, substrate electrical conductivity was higher using subirrigation methods (0.84–1.3 ds m−1) than under overhead irrigation (0.55–0.8 ds m−1), but there were no symptoms of salt stress observed in plants at any time. Results from this study show that ebb-and-flow is a viable alternative to overhead irrigation and is superior to capillary mats for water conservation. In automated ebb-and-flow systems in Florida, we recommend using the 0.24 m3 m−3 threshold to produce the citrus rootstock cultivars used in this study with peat: perlite substrate.

Incorporating a Ferrous Polymer Target into Elastomeric Liners for Socket Fit Sensing in Prosthesis Users.

Liner-to-socket distance measurement using inductive sensing may be an effective means to continuously monitor socket fit in people using trans-tibial prostheses. A practical limitation, however, is a means to incorporate a thin uniform-thickness layer of conductive or magnetically permeable target material into the wide range of prosthetic liner products that people with limb amputation commonly use. In this paper, a method is presented whereby a 0.50-mm thickness ferrous polymer made from a SEEPS polymer and iron powder that is formed adjacent to a 0.25-mm thick non-ferrous layer of SEEPS polymer is assembled between two sheets of elastic fabric material. Bench testing showed that the fabrication procedure achieved a root-mean-square error in the thickness of this construct of 58 μm, helping to create a consistent calibration result over the entire surface. The original fabric backing of an off-the-shelf prosthetic liner was removed and replaced with the developed construct. When worn in the shoe of an able-bodied participant for 7.5 h per day for 28 days, the sensor well maintained the shape of its calibration curve at the start of wear, but a distance offset (shifting of the y-intercept) was introduced that increased during the initial approximately 12 days of wear. When the distance offset was corrected, for the primary distance range of clinical interest for this application (0.00–5.00 mm), the sensor maintained its calibration within 4.4%. Before being used in clinical application for liner-to-socket distance monitoring, new ferrous liners may need to be pre-worn so as to achieve a consistent distance reference.

Citrus Nursery Production Guide, Chapter 7: Seed and Budwood Production, Transport, and Conservation

The Florida citrus industry maintains a high demand for trees for replanting and resetting, as well as an interest in new releases of rootstocks and scions with improved disease and abiotic stress tolerances. One of the main constraints for liner production in great numbers is time. The consensus among citrus nurseries is that it takes two years to produce enough quantities of budwood to establish seed block trees when a new interesting rootstock is produced. This new 3-page article addresses the practices and challenges of producing seeds and budwood in Florida. This article, chapter 7 of the forthcoming Citrus Nursery Production Guide, was written by Fernando Alferez and Mireia Bordas and is a publication of the UF/IFAS Horticultural Sciences Department. https://edis.ifas.ufl.edu/hs1336

Chemical interaction and hydraulic performance of geosynthetic clay liners isothermally hydrated from silty sand subgrade

The effects of the silt aggregation, compaction density, and water content of the subgrade on the hydration of five different geosynthetic clay liner (GCL) products is reported based on a series of laboratory column experiments conducted over a six-year period. GCLs meeting typical specifications in terms of minimum hydraulic conductivity and swell index are hydrated to equilibrium from the same subgrade soil with sufficient cations to cause cation exchange during hydration. It is then shown that the GCL bentonite granularity and GCL structure can have a significant (~four orders of magnitude) effect on hydraulic conductivity under the same test conditions (from 8 × 10−12 m/s for one GCL to 6 × 10−8 m/s for another GCL product). The effect of subgrade water content on the hydraulic performance of GCLs are not self-evident and quite dependent on the bentonite granularity, GCL structure, and permeant. Varying the subgrade water content from 5 to 16% and allowing the GCL to hydrate to equilibrium before permeation led to up to 5-fold difference in hydraulic conductivity when permeated with tap water and up to 60-fold difference when the same product is permeated with synthetic municipal solid waste leachate. When permeated with synthetic leachate, increasing stress from 70 kPa to 150 kPa led to a slight (average 37%; maximum 2.7-fold) decrease in hydraulic conductivity due to a decrease in bulk void ratio. It is shown that hydraulic conductivity is lower for GCLs with a scrim-reinforced geotextile, and/or with finer bentonite. It is shown that selecting a GCL based on the initial hydraulic conductivity and swell index in a manufacturers product sheet provides no assurance of good performance in field applications and it is recommended that designers pay more attention to selection of a GCL and preparation of the subgrade for important projects.

Stock Plant and Tree Production: Irrigation and Fertilization

Citrus tree production in nurseries can be divided into three stages: production of rootstock liners, transplant of rootstocks into larger containers, and bud grafting. The objectives of this new 6-page publication of the UF/IFAS Horticultural Sciences Department are to provide general information on irrigation and fertilization for production of citrus nursery trees in seedbeds, nurseries and budwood multiplication blocks. This article, written by Rhuanito Soranz Ferrarezi, is chapter 8b of the forthcoming Citrus Nursery Production Guide. https://edis.ifas.ufl.edu/hs1333