Double Polyethylene Research Articles

Formation of liquid and solid bridges under the interactions between droplet-polyethylene particle pairs

The formation mechanism of liquid and solid bridges between particles and their effects in a gas–solid fluidized bed with liquid injection on particle aggregation is essential for the operational controls and improve operations. We used high-speed imaging, infrared thermography, and scanning electron microscope (SEM) to study the liquid film behaviors during the collision between droplets and double polyethylene particles and the formation of solid bridges. Three modes of solid bridge formation were found: the liquid film stimulated slow growth, the liquid bridge stimulated intermittent growth, and the liquid bridge stimulated rapid growth. The different growth positions and growth rate of the solid bridge of the three forms show that the influence of particle wetting degree is stronger than the liquid holding capacity on the solid bridge growth characteristic.

Effect of sealing on the feed out face of trench silos on the performance of confined calves

ABSTRACT This study aimed to evaluate the productive performance, dry matter intake, apparent digestibility and ingestive behavior of feedlot calves fed corn silage from the feed out face of trench silos with different types of sealing. The animals were divided into three treatments with four repetitions: Conventional seal - double-sided polyethylene of 110µm thickness; Double-sided seal - double-sided polyethylene of 200µm thickness; and Double seal - composed of double face polyethylene with a thickness of 80µm superimposed on a polyamide translucent vacuum film with a thickness of 20µm. The use of double face sealing provided 12.63% increase in average daily gain and improved food conversion by 0.62 percentage points. The apparent digestibility of the diet with double-face sealing system silage was 4.30% higher than the diet with double-face sealing silage and 11.00% higher than the diet with conventional sealing silage. It is recommended to use the double face sealing with 200µm polyethylene and double face sealing with 80µm thick polyethylene on top of a 20µm thick polyamide translucent vacuum film.

Intranasal delivery of plasmids expressing bovine herpesvirus 1 gB/gC/gD proteins by polyethyleneimine magnetic beads activates long-term immune responses in mice

BackgroundDNA vaccine is one of the research hotspots in veterinary vaccine development. Several advantages, such as cost-effectiveness, ease of design and production, good biocompatibility of plasmid DNA, attractive biosafety, and DNA stability, are found in DNA vaccines.MethodsIn this study, the plasmids expressing bovine herpesvirus 1 (BoHV-1) gB, gC, and gD proteins were mixed at the same mass ratio and adsorbed polyethyleneimine (PEI) magnetic beads with a diameter of 50 nm. Further, the plasmid and PEI magnetic bead polymers were packaged into double carboxyl polyethylene glycol (PEG) 600 to use as a DNA vaccine. The prepared DNA vaccine was employed to vaccinate mice via the intranasal route. The immune responses were evaluated in mice after vaccination.ResultsThe expression of viral proteins could be largely detected in the lung and rarely in the spleen of mice subjected to a vaccination. The examination of biochemical indicators, anal temperature, and histology indicated that the DNA vaccine was safe in vivo. However, short-time toxicity was observed. The total antibody detected with ELISA in vaccinated mice showed a higher level than PBS, DNA, PEI + DNA, and PBS groups. The antibody level was significantly elevated at the 15th week and started to decrease since the 17th week. The neutralizing antibody titer was significantly higher in DNA vaccine than naked DNA vaccinated animals. The total IgA level was much greater in the DNA vaccine group compared to other component vaccinated groups. The examination of cellular cytokines and the percentage of CD4/CD8 indicated that the prepared DNA vaccine induced a strong cellular immunity.ConclusionThe mixed application of plasmids expressing BoHV-1 gB/gC/gD proteins by nano-carrier through intranasal route could effectively activate long-term humoral, cellular, and mucosal immune responses at high levels in mice. These data indicate PEI magnetic beads combining with PEG600 are an efficient vector for plasmid DNA to deliver intranasally as a DNA vaccine candidate.

Techno-economic analysis of solar greenhouses

ABSTRACTGreenhouses are used in agriculture to control climate allowing crops to be grown year-round. To evaluate greenhouse efficacy, the monthly heat requirement was determined using two types of 1-dimensional dynamic calculation models in two types of greenhouses at six locations. Climate parameters and geographical conditions of locations were determined. The cost of a gable-roofed double polyethylene (PE) greenhouse was 10% greater than an arc-roofed double PE greenhouse of the same size. The models demonstrated good agreement indicating use of either was valid. The arc-roofed type greenhouse had more heat loss than the gable-roofed greenhouse of the same size and decisions on type of greenhouse to use will have to be made based on a cost: benefit analysis of the greenhouse types and the crops grown.

Novel method based on fourier transform infrared spectroscopy for determining fat acidity of cereal products

ABSTRACTA novel method based on Fourier transform infrared spectroscopy was developed to determine fat acidity (FA) in cereal products. Disposable double polyethylene films were used as a spectral acquisition accessory. Oil was extracted from cereal products using a solvent followed by ultrasonication. The calibration curve of peak height (1716/1600 cm−1) and FA was developed by using hexanoic acid added to rapeseed oil and solvent solution. The oil-dependent absorption of the calibration at a peak of 1716/1600 cm−1 was corrected by the first overtone of ester at 3479/3518 cm−1. Subsequently, different types of blind samples were used to validate the calibration. An excellent linear relationship was determined between the FA determined using the proposed method and the ISO 7305:1998 method, with a correlation coefficient of 0.9980. Therefore, the proposed procedure can be used as an alternative to the standard method in determining the FA of cereal products.

Stability of spray-dried chitosan salts derived from lobster chitin as a raw material

Aim. The objective of this work was to develop and validate a method for determining the degree of molar deacetylation of chitosan acetate and chitosan lactate, as well as to study the stability of both salts. Materials and Methods. A spectrophotometric method was validated according to internationally-established quantitative techniques. Three industrial batches of chitosan acetate and chitosan lactate, obtained by spray drying, were stored under shelf life conditions for twelve months. Organoleptic characteristics, the degree of molar deacetylation, pH, loss on drying and microbiological count were determined at the beginning and end of the study. Results and Discussion. The statistical data proved that the two methods complied with international standards for the validation of analytical techniques. It was shown that the procedures developed were linear, specific, precise and accurate, so they can be used for the purposes of quality control and stability study of the polymer salts. Salts remained in powder form, with a light-yellow to dark-yellow coloration. Values of loss on drying (2.5 - 5.2 %) of chitosan salt using acetic or lactic acid, as a solvent, indicated the good quality of spray-dried particles of chitosan. Similar behavior was obtained regarding pH. The two salts stayed within the parameters that determine their quality, both in the initial stage and after twelve months at room temperature. Conclusion: Spray drying chitosan acetate and chitosan lactate, stored at room temperature in a dry place, in double polyethylene bags and multilayer paper bags, kept their physical, chemical and microbiological characteristics for a period of twelve months.

Improvement of butt-welding characteristics of double wall polyethylene pipes

In this study, a new heat plate with a groove for butt-welding was developed to investigate the misalignment effects on the joining strengths of polyethylene double walled pipes. Thermal analyses of the material determined the temperature profile of the welding. After the welding, the joining characteristics of the pipes were compared with those welded by the conventional heat plate. The results of the stiffness and flattening tests showed that there were no big differences between the joints made from these two plates. In the leakage test, however, the pipes welded with the conventional heat plate leaked below the required test conditions, while the pipes welded with the grooved heat plate did not show any leakage, even in a range higher than the required conditions. The tensile and bending strength were also improved. The results demonstrated that the grooved heat plate accomplished more complete fusion at the pipe joints and induced high quality joints.

Enhanced Soil Solarization againstFusarium oxysporumf. sp.lycopersiciin the Uplands

Soil solarization tests againstFusarium oxysporumf. sp.lycopersici, the causal agent of tomato Fusarium wilt, were conducted for seven weeks through July and August 2008 and 2009 in the climatic conditions of Al-Aroub Agricultural Experimental Station, located in the southern mountains of the West Bank, Palestine. Double polyethylene (DPE) sheets, regular polyethylene (PE) sheets, and virtually impermeable films (VIF) were compared to examine their effects on soil temperature, disease severity, and plant growth. Results showed that in comparison to the control, PE, DPE, and VIF treatments increased the mean maximum soil temperatures by 10.2, 14.1, and 8.8°C, respectively, in 2008 and by 10.2, 12.6, and 8.3°C respectively, in 2009. The longest length of time recorded for temperature above 45°C under DPE sheets were 220 hours in 2008 and 218 hours in 2009. The treatments reduced the pathogen population by 86% and the disease by 43% under the DPE treatment in 2009 and to a lesser extent by the other treatments. Increases of up to 94% in fresh plant weight and up to 60% in plant dry weight were evident under the same treatment. The treatments also increased soil organic matter, both nitrogen forms, and major cations.

Energy Saving Achieved by Retractable Liquid Foam between Double Polyethylene Films Covering Greenhouses

Heating is a major cost component in greenhouse crop production. A retractable liquid foam insulation technology was developed recently in Canada to reduce energy use for greenhouse heating. The system dynamically generates and injects liquid foam into the cavity between two polyethylene films in the greenhouse roof. Several experiments were conducted in southwestern Ontario, Canada, from December 2007 through May 2008 to evaluate the energy saving potential of this technology. The liquid foam system was installed in two independent greenhouses; in one of them, the system was shut off to serve as control. The foam was used only during the night for greenhouse insulation. In December 2007, no crop was grown inside the greenhouses. During the first five months of 2008, tomato (Lycopersicon esculentum) and sweet pepper (Capsicum annuum) plants were grown inside both greenhouses. Natural gas consumption for heating, and inside microclimate and outside climatic conditions (air and leaf temperature, humidity, solar radiation, and wind speed) were recorded. Heat loss from the roof with or without liquid foam was calculated. During December 2007, the liquid foam reduced the heat loss through the roof by 31%. During 2008, the heat loss was reduced by 29%, 36%, and 42% for January, February, and March, respectively. A larger reduction in roof heat loss (higher energy saving) was recorded during spring nights: 62% and 58% in April and May 2008, respectively. Therefore, the liquid foam showed a good energy saving potential (29% to 62%), but its energy saving decreased with low outside temperature. Further improvement in liquid foam formulation may be needed to increase its energy saving potential during the winter under low outside temperature conditions. Finally, liquid foam insulation resulted in higher greenhouse air temperature and plant leaf temperature; this should benefit plant growth and development and promote early yield.

Survival of Ucides cordatus (Decapoda: Ocypodidae) megalopae during transport under different conditions of density and duration

Target areas for Ucides cordatus (Linnaeus, 1763) restocking programs are often located far from the laboratory where larval rearing is developed. During translocation, the larvae are submitted to highly stressful conditions due to handling, packing, and transport activities. The aim of the present study was to assess the mortality rates of U. cordatus megalopae caused by different transportation procedures. Megalopae at loading densities of 50, 150, and 300 ind.L-1 were packed in double polyethylene 12 x 25 cm plastic bags with 200 ml of marine water at salinity 30. The bags were filled with oxygen at a proportion of 1:2 parts of water and sealed tightly. The trepidations during transport were simulated by the use of a shaker device (800 vibrations/minute) over periods of three and six hours inside a dark container. The survivorship rates of larvae after simulation were compared to those obtained in control groups, which consisted of plastic vials with megalopae at a loading density of 50 ind.L-1 maintained at rest. Immediately after the two transport simulations, there was no significant difference in survivorship between the treatments and the control. However, 24 hours after simulation some of the tested densities resulted in significantly lower survivorships. The results demonstrated that U. cordatus megalopae can tolerate six hours of shaking during transportation, at high densities with minimal mortality.

EFFECT OF LIGHT QUALITY ON GROWTH OF EVERBEARING STRAWBERRY PLANTS

The effects of various light sources for night irradiation on the growth of everbearing strawberry plants (Fragaria × ananassa Duch. 'Natsuakari') were investigated. The experiment was conducted in natural light-type phytotrons in which the day (6:00-18:00) / night (18:00-6:00) temperatures were controlled to 25/20°C. Plants were grown under natural daylight from 9:00 to 17:00, and were covered with a double silver polyethylene film from 17:00 to the following 9:00. Except in the case of plants receiving the 8-h photoperiod treatment (8-h), supplemental light was provided with white incandescent lamps (W), red fluorescent lamps (R), or far-red fluorescent lamps (FR) from 17:00 to 9:00. The experiment was carried out for 16 weeks, from 7 July 2006 to 26 October 2006. During the test period, leaves expanded continuously under all treatments, but more leaves expanded under the R light than under the 8-h, W, or FR light. In contrast, the number of inflorescences per plant was highest under the FR light, followed by the W, R, and 8-h light. Under the R light, the number of inflorescences was almost the same as that of under the 8-h light. These results indicated that inflorescence production of everbearing strawberry plants is promoted by FR light and leaf production is promoted by R light.

Thermal modeling of greenhouse aquaculture raceway systems

A mechanistic model was developed to describe the thermal behavior of an indoor raceway system with an inflated double polyethylene cover. The model describes the heat balances of the two covers, the inside air, the water in the raceway and the soil beneath the raceway. On-site measurements were made with an experimental system at the Waddell Mariculture Center in South Carolina. The collected data were used to calibrate the model. Comparison of the predictions with observations showed that the average absolute errors of air temperature and water temperature were 1.4 and 0.5 °C, respectively and was 8% for the relative humidity. The accuracies are regarded as sufficient for the model to be useful for more general application. Model simulations were used to investigate the effects of the greenhouse on the air and water temperatures, to examine the heat fluxes and to calculate the heat consumption and costs at four different climatic locations. The results suggest that under the mild weather conditions in January near Charleston, SC where the daily mean temperature is 7.6 °C and solar radiation is 121 W m −2, the inside air temperature increases by 5.6 °C and water temperature increases by 9.7 °C on average for the system with the 0.85 m deep raceway covering 70% of the greenhouse floor. An examination of the heat fluxes suggests that thermal radiation is a major mechanism of heat loss for the greenhouse covers and the water surface. Convection from the water surface is also a significant mechanism for latent and sensible heat loss from the raceway. Reducing these heat flows will help conserve and utilize energy. The yearly heating requirements to keep the water temperature at 28 °C for the experimental system were estimated to be 870, 520, 274 and 221 kWh per square meter of raceway for Syracuse, NY, Roanoke, VA, Charleston, SC and Baton Rouge, LA, respectively. The model was deemed to be a useful tool for exploring the performance of greenhouse raceway systems under different scenarios, such as different cover materials, sizes and climates.

Microclimate Study Conditions in Different Types of Protected Spaces

The researches where carried out in the Vegetable Growing Department experimental plots between 2006-2008. For the comprehensive microclimate study where used the latest technology gadgets: termohigrometer Aquaterr T300 (used for soil temperature and humidity determination), termohigrometer HI 9161 (used for soil and environment temperature readings, air humidity readings), light intensity meter Testo 545. The paper wants to reveal the differences between microclimate conditions in two constructive types of unheated greenhouses. Regarding the soil evapotranspiration rate all the unmulched experimental variants recorded the highest evapotranspiration rate compared with the black plastic films mulched variants. The microclimate conditions where properly controlled in the double covered polyethylene tunnel compared with the unheated greenhouse. The temperature, air humidity and light intensity where efficient conducted in the case of double cover protection.

Gas-phase transfer of polymer cross-linking agents and by-products to solid oral pharmaceuticals

In the pharmaceutical industry, solid oral compressed tablets (OCT) are frequently transported in bulk containers prior to packaging. While in this state, the product is generally protected from interaction with liquid and solid contaminants by physical barriers (e.g., polyethylene bags, drums, etc.). Vapor phase contamination, although generally less frequently observed, is possible. A specific example of the detection and identification of volatile by-products (acetophenone and 2-phenyl-2-propanol) of a common polymer cross-linking agent (dicumyl peroxide) is presented. The product tablets were compressed, placed into double polyethylene bags, and subsequently placed into a polyethylene drum for shipment overseas. To cushion the product during transit, a cross-linked polyethylene foam disk (designed to fit into the bottom of the drum) was placed below the bag of tablets. Initially, these contaminants were detected by HPLC with UV detection at the receiving laboratory, and assumed to be degradates of the active components of the product. Further analysis showed that neither the collected UV absorbance data nor the observed levels of the contaminants were consistent with known degradates of the product. Liquid extraction followed by GC–MS analysis of the product as well as the cross-linked foam disk exhibited measurable quantities of the contaminants in question. Vapor phase transfer of these cross-linking agent by-products, originating in the cross-linked foam pads, was determined to be the root cause for the presence of these compounds in the product.

DYNAMIC MODELING OF MICROCLIMATE AND ENVIRONMENTAL CONTROL STRATEGIES IN A GREENHOUSE COUPLED WITH A HEAT PUMP SYSTEM

ISHS III International Symposium on Models for Plant Growth, Environmental Control and Farm Management in Protected Cultivation (HortiModel 2006) DYNAMIC MODELING OF MICROCLIMATE AND ENVIRONMENTAL CONTROL STRATEGIES IN A GREENHOUSE COUPLED WITH A HEAT PUMP SYSTEM

PENDUGAAN UMUR SIMPAN TEPUNG PISANG (MUSA PARADISIACA) DALAM KEMASAN KOMERSIAL

This research was done in orderto predict shelf life of banana fruit flour (Musa poradisiacai in commercial packaging storage, using Accelerated Storage Studies reffered lo Arrhenius model. The commercial packaging using cloths bag, polyethylene film (0,005 mm thickness), and double polyethylene film (0,0 IO thickness). Each bags contains 50 gram samples. These samples were storaged indifferent condition, i.e. 30°C, 35°C and 45°C, in 80% relative humidity (RH) atmosphere for six weeks storage. Once in every week, the samples were evaluated on its critical water content. The results showed that the sample packaged in cloths bag can survive until 2.4 month storage. in polyethylene mono layer until 2.8 month and in double polyethylene until 4.2 month.

The capacity of benthos release panels to reduce the impacts of beam trawls on benthic communities

Ecosystem-based fishery management requires that both a fishery and the environment associated with that fishery should be sustainable. Beam trawling has widespread effects on the biomass, production and diversity of benthic communities and in some fisheries, the impact is deleterious. Beam trawls impact benthic communities because the ground gear crushes and dislodges animals on the seabed, and because animals are caught in the trawl and subsequently die. Based on a study of the relative performance of seven designs of benthic release panels in commercial beam trawl fisheries, we demonstrate that panel designs consisting of 150 mm × 5 mm ø double polyethylene square mesh or 150 mm × 6 mm ø single polyethylene square mesh, respectively, reduced invertebrate bycatches by 75 and 80%, and that >90% of the animals released survived. We conclude that the use of benthic release panels may reduce the overall environmental impact (expressed as invertebrate mortality) of beam trawl fisheries by 5–10% without affecting their profitability. Other techniques to reduce the environmental impact of beam trawling are also discussed.

A randomized prospective trial comparing the double layer™ stent and polyethylene stent for malignant biliary strictures: Preliminary results

A randomized prospective trial comparing the double layer™ stent and polyethylene stent for malignant biliary strictures: Preliminary results

264 Identification and Characterization of Overwintering Methods for Container-grown Herbaceous Perennials

A survey was conducted to identify and characterize the effectiveness of overwintering methods used to protect container-grown herbaceous perennials in USDA hardiness zones 3 through 8. Survey questionnaires were sent by first-class mail on 20 Aug. 1996 to 634 firms involved in growing and/or selling container-grown herbaceous perennials identified from the Perennial Plant Association Membership Directory. Completed questionnaires were received from 293 individuals (46.2% response rate) in 38 states, the District of Columbia, and six Canadian provinces. Survey participants reported using several overwintering methods: structureless systems (71.0%), polyhouses (52.9%), polyhouses with inflated double polyethylene covers (30.7%), and low-profile polyhuts (12.3%). Over three-fourths of the respondents (78.8%) said their winter protection methods resulted in minimal to no plant loss (0-10%). Only 53 respondents (18.1%) reported losses >10%. The most frequently cited reason for plant loss across all hardiness zones was excessive moisture inside the overwintering environment (50.2%). Equal percentages (33.4%) indicated low temperatures and damage from animals as the next most likely factors responsible for plant loss. Respondents identified, in descending order, Iris, Delphinium, Lavandula, Papaver, and Lupinus as the five genera most difficult to overwinter.

Efficiency of a New Covering System for the Environmental Control of Biopiles Used for the Treatment of Contaminated Soils

The objectives of the study were to first characterize a new covering system that allows the temperature inside the biopiles to be maintained at a level where biodeg-radation can take place despite unfavorable climatic conditions, and then second to develop a mathematical simulation of the biopile temperature profile knowing local meteorological conditions and the covering system used. A field study was undertaken with four 60 m3 biopiles of contaminated soil. The performance of conventional semipermeable black geotextile was compared with that of two sealed double polyethylene membrane systems (a white/white and a black/translucid polyethylene membrane). Heat transfer was favored or restricted by choosing the color of the polyethylene membranes and by the presence of an insulating air layer between the two polyethylene membranes. Results showed that the air layer allowed to increase soil temperature up to a range that could enhance biodegradation. For example, the biopile temperature was maintained above 10°C during fall conditions using the double membrane system, while it remained between of 5 to 10°C when using the conventional black geotextile. The white/white polyethylene membrane was considered to be the covering system offering the best performance because it allowed not only the temperature level to increase during fall conditions but also to reduce the temperature gradient within the biopile. A mathematical model describing the temperature profile within a biopile was developed, taking into account soil thermal properties, covering material properties, and local meteorological conditions. Close agreements between simulation results and actual measurements were found with maximum deviation within 2°C. This validated model can now be used to predict thermal profiles within biopiles without costly tests on site.